101
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Chen Q, Hu Y, Xia Z. [The effects of ZMS on learning and memory ability and brain choline acetyltransferase in scopolamine-induced mouse model]. Zhong Yao Cai 2001; 24:496-8. [PMID: 11668742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
OBJECTIVE To observe the effects of ZMS on learning and memory ability and on brain choline acetyltransferase activity. METHODS A single intraperitoneal injection of scopolamine was used to establish a dementia mouse model. The learning and memory ability was detected by step-through and sted-down tests. And the choline acetyltransferase activity in brain was determined by 3H-acetyl-CoA incorporation analysis. RESULTS ZMS could significantly reduce wrongness frequences, prolong incubation period of scopolamine-induced dementia mice in step-through and step-down tests (P < 0.01). ZMS could also significantly improve the activity of brain choline acetyltransferase (ChAT) (P < 0.01). CONCLUSION ZMS could improve the learning and memory ability and the activity of brain ChAT in scopolamine-induced dementia mice. However, ZMS had no significant dose-response effect on improving the activity of brain ChAT, and the effect of Tacrine was similar to that of ZMS, it seemed unlikely that ZMS had a direct action on the ChAT. More probably, ZMS exerted its effect on ChAT activity and on learning and memory ability via elevating brain M receptor density.
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Affiliation(s)
- Q Chen
- Shanghai Second Medical University, Shanghai 200025
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102
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Figueroa-Masot XA, Hetman M, Higgins MJ, Kokot N, Xia Z. Taxol induces apoptosis in cortical neurons by a mechanism independent of Bcl-2 phosphorylation. J Neurosci 2001; 21:4657-67. [PMID: 11425893 PMCID: PMC6762365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
Bcl-2, an antiapoptotic protein, protects cells against many but not all forms of apoptosis. For example, Bcl-2 does not protect non-neuronal cells against taxol, a microtubule-stabilizing agent. The underlying mechanism for the ineffectiveness of Bcl-2 against taxol has been the subject of intense interest. Data from non-neuronal cells indicate that taxol-induced apoptosis requires activation of N-terminal c-Jun protein kinase (JNK) that phosphorylates and inactivates Bcl-2. This suggests the interesting possibility that the apoptotic activity of JNK may be caused by phosphorylation of Bcl-2 and inhibition of the antiapoptotic activity of Bcl-2. Here we report that taxol induces apoptosis in cortical neurons but by a mechanism significantly different from that in non-neuronal cells. In contrast to human embryonic kidney 293 cells, expression of wild-type Bcl-2 in cortical neurons protected against taxol-induced apoptosis, and taxol did not induce Bcl-2 phosphorylation. Furthermore, cortical neurons express high basal JNK activity, and taxol did not stimulate total JNK activity. However, taxol activated a subpool of JNK in the nucleus and stimulated c-Jun phosphorylation. JNK inhibition or expression of a dominant-negative c-Jun abrogated taxol-induced apoptosis in cortical neurons, suggesting a role for JNK and JNK-mediated transcription in taxol-stimulated apoptosis. Furthermore, taxol-induced apoptosis in cortical neurons required inhibition of phosphatidylinositol 3-kinase signaling. These data suggest that taxol induces apoptosis in neurons by a mechanism quite distinct from that of non-neuronal cell lines and emphasize the importance of elucidating apoptotic mechanisms specific for neurons in the CNS.
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Affiliation(s)
- X A Figueroa-Masot
- Departments of Environmental Health and Pharmacology, Graduate Program in Neurobiology and Behavior, University of Washington, Seattle, Washington 98195-7234, USA
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103
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Abstract
The Ca2+-stimulated type 1 adenylyl cyclase (AC1) contributes to several forms of synaptic plasticity and is the only known neurospecific adenylyl cyclase. Furthermore, the protein and mRNA levels of AC1 undergo a circadian oscillation in the pineal gland, and AC1 may play a pivotal role in regulating nocturnal melatonin synthesis. To better understand the expression of AC1, we isolated mouse genomic DNA clones of AC1. The transcription and translation start regions of mouse AC1 share extensive homologies with the bovine counterpart. The upstream proximal region has potential binding sites for transcription factors, including the steroid receptor family, the E-box factors, and Sp1. A 280-bp fragment that contains the transcription start site directed reporter gene expression in cultured cortical neurons and pinealocytes functioning as a basal neuro- and pineal-directed promoter. Interestingly, pinealocyte expression of the reporter gene was inhibited by increases in cAMP. This cAMP sensitivity may explain why AC1 mRNA in the pineal is low at night when cAMP is elevated and high during the day when cAMP signals drop. An adjacent 330-bp fragment interacted specifically with nuclear factor(s) that we designate binary E-box factor (BEF). Methylation interference and DNase I footprinting identified the BEF-binding site sequence as 5'-CCAAGGTCACGTGGC-3'. When linked to the basal tissue-directed promoter, this 15-bp sequence further enhanced reporter expression in neurons and pinealocytes. We propose that this 15-bp sequence may contribute to increased expression of AC1 in neurons and pinealocytes relative to other cells.
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Affiliation(s)
- G C Chan
- Department of Pharmacology, Box 357280, University of Washington, Seattle, WA 98195, USA
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104
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Xia Z, Sait SN, Baer MR, Barcos M, Donohue KA, Lawrence D, Ford LA, Block AM, Baumann H, Wetzler M. Truncated STAT proteins are prevalent at relapse of acute myeloid leukemia. Leuk Res 2001; 25:473-82. [PMID: 11337019 DOI: 10.1016/s0145-2126(00)00158-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Signal transducer and activator of transcription (STAT) proteins are implicated in the control of cell survival, proliferation and differentiation in response to hematopoietic cytokines. C-terminally truncated STAT isoforms (STATbeta), as opposed to the full length form (STATalpha), have a competitive or even transdominant negative effect on gene induction mediated by the STAT pathway. We have previously demonstrated that while constitutively active STAT proteins were detected in ten of 36 (28%) for STAT3 and eight of 36 (22%) for STAT5 in pretreatment samples from newly diagnosed acute myeloid leukemia (AML) patients, a significantly larger fraction of samples [21 of 27 (78%)] expressed STATbeta proteins. To determine whether STATbeta expression was maintained or increased after relapse in AML, we compared STAT activity and isoform expression at diagnosis and at relapse in 17 patients. In this selected group, constitutively active STAT3 was detected in 13 of 17 (76%) AML samples at diagnosis but was detected in only four of these patients at relapse. Constitutively active STAT5 was detected in three of 17 (18%) AML samples at diagnosis; but only two at relapse. In contrast, STATbeta protein expression was observed in 12 of the 17 pretreatment samples (71%) and in 16 of 17 samples at relapse. Only one patient did not express STATbeta at relapse. Our results suggest that STATbeta isoform expression, rather than level of constitutive activity, may be involved in disease progression in AML.
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Affiliation(s)
- Z Xia
- Leukemia Section, Department of Medicine, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA
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105
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Abstract
Dendroamide A (1) was isolated from a blue-green alga on the basis of its ability to reverse drug resistance in tumor cells that overexpress either of the transport proteins, P-glycoprotein or MRP1. Because of this activity, methods for the synthesis of analogues of this oxazole- and thiazole-containing cyclic peptide have been developed, and the total synthesis of 1 has been completed. Highlights of the synthetic strategy are as follows: (1) a dicyclohexylcarbodiimide coupling of D-Ala and L-Thr, followed by reaction with Burgess reagent and DBU-assisted oxidation to form D-Ala-oxazole; (2) formation of D-Val-thiazole and D-Ala-thiazole via modified Hantzsch reactions; and (3) use of molecular modeling to select the preferred precursor for the final cyclization of the peptide analogue. Synthetic 1 demonstrated spectral properties identical to those of the natural product and reversed P-glycoprotein-mediated drug resistance more effectively than MRP1-mediated resistance. Certain of the synthetic precursors had biological activity, indicating that cell permeability and peptide cyclization are necessary for optimal activity. Thus, the structure and the biological activities of the natural product are confirmed, and methods for the synthesis of analogues for further structure-activity explorations are defined.
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Affiliation(s)
- Z Xia
- Department of Pharmacology, Pennsylvania State University, Hershey, PA 17033, USA
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106
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Xia Z, Shao J, Shen Q, Wang J, Li Y, Chen S, Yu S. The preparation of rat heme oxygenase-1 mutant to reduce the level of bilirubin. Chin Med J (Engl) 2001; 114:348-51. [PMID: 11780451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
OBJECTIVE To prepare rat heme oxygenase-1 (HO-1) mutants and to determine the activity and inhibition of this mutated enzyme. METHODS pcDNA3HO1 containing truncated native rat HO-1 cDNA and pcDNA3HO1 delta 25 carrying mutated rat HO-1 cDNA (His25Ala) were constructed, respectively. COS-1 cells transfected with pcDNA3HO1 and pcDNA3HO1 delta 25 were collected and their activities were analyzed. RESULTS Native rat HO-1 was highly expressed in transfected cells and its activity was 13,688-15,600 U/mg protein per hour. However, the enzyme activity of mutated HO-1 declined and the value was 1948-2160 U/mg protein per hour. When an equal amount of mutant was added to the enzyme reaction system, the level of bilirubin decreased by 42%. CONCLUSION The His25Ala mutant reduced the formation of bilirubin, suggesting that the mutant could completely bind the heme with native enzyme.
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Affiliation(s)
- Z Xia
- Department of Pediatrics, Rui Jin Hospital, Shanghai Second Medical University, Shanghai 200025, China
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107
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Liu L, Cui G, Xia Z. [Modeling research about bioremediation of organic pollutants in soil-water-microbes system]. Huan Jing Ke Xue 2001; 22:101-5. [PMID: 11432053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
A new Theory, organic pollutant sequestration inside soil particles, was applied in the research in order to explain the persistence of residual chemicals in remediation sites. Based on this theory, a mathematical model which simulates organic pollutant bioremediation process in soil-water-microbes system was developed. In the model, diffusion is represented by Fick's second law, reversible sorption-desorption by a linear isotherm, irreversible sequestration by a pseudo-first order kinetics, and biodegradation by Monod kinetics. Model results match successfully with experimental data. Model simulations are performed in the study. It is noteworthy that the mathematical model will be useful in quantitatively predicting the time and degradation extend of organic pollutant in remediation sites.
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Affiliation(s)
- L Liu
- Water Resources Development and Utilization Laboratory, Hehai University, Nanjing 210098, China.
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108
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Xia Z, Liu Y, Jiao H. [Researches on high frequency inverter in X-ray machine]. Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 2001; 18:156-7. [PMID: 11332100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
This paper mainly explicates the high frequency inverter circuit and its features and deliberates the question of how to prevent the short circuit of inverter.
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Affiliation(s)
- Z Xia
- First University Hospital, West China University of Medical Sciences, Chengdu 610041
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109
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Xia Z, Salzler RR, Kunz DP, Baer MR, Kazim L, Baumann H, Wetzler M. A novel serine-dependent proteolytic activity is responsible for truncated signal transducer and activator of transcription proteins in acute myeloid leukemia blasts. Cancer Res 2001; 61:1747-53. [PMID: 11245492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Hematopoietic cytokine receptor signaling involves activation of signal transducer and activator of transcription (STAT) proteins that are thought to control cellular differentiation. Truncated STAT isoforms (beta forms, rather than the normal alpha forms) have been described and found to block the normal signaling function of the alpha isoforms. We recently demonstrated STATbeta isoforms in bone marrow samples from 21 of 27 (78%) acute myeloid leukemia (AML) patients. We sought to determine the mechanism by which the STATbeta forms were generated. Samples from eight newly diagnosed AML patients were studied; four expressed predominantly STATalpha, and four expressed predominantly STATbeta. The reverse transcription-PCR generated identical products in the two groups, suggesting that alternate mRNA splicing is not responsible for the genesis of STATbeta. Extracts from cells expressing predominantly STATbeta incubated with cell extracts from the MO7E cell line, which expresses predominantly STATa, caused a decrease of the alpha isoforms and an increase of the beta isoforms, suggesting the presence of proteolytic activity. This proteolytic activity was: (a) specific for STAT3 and STAT5, but not for STAT6; (b) serine dependent; (c) equally present in nuclear and cytoplasmic fractions of the leukemic blasts; and (d) different than the activity detected in a murine hematopoietic cell line. The cleaved beta isoforms retained their DNA-binding activity. Because expression of truncated STATs may be involved in blocking differentiation of AML blasts, elucidation of the regulation of the proteolytic activity may contribute to our understanding of leukemogenesis.
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Affiliation(s)
- Z Xia
- Department of Medicine, Biopolymer Facility, Roswell Park Cancer Institute, Buffalo, New York 14263, USA
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110
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Abstract
OBJECTIVE To determine risk factors for pregnancy after tubal sterilization with silicone rubber bands or spring clips. METHODS A total of 3329 women sterilized using silicone rubber bands and 1595 women sterilized using spring clips were followed for up to 14 years as part of a prospective cohort study conducted in medical centers in nine US cities. We assessed the risk of pregnancy by cumulative life-table probabilities and proportional hazards analysis. RESULTS The risk of pregnancy for women who had silicone rubber band application differed by location of band application and study site. The 10-year cumulative probabilities of pregnancy varied from a low of 0.0 per 1000 procedures at one study site to a high of 42.5 per 1000 procedures in the four combined sites in which fewer than 100 procedures per site were performed. The risk of pregnancy for women who had spring clip application varied by location of clip application, study site, race or ethnicity, tubal disease, and history of abdominal or pelvic surgery. The probabilities across study sites ranged from 7.1 per 1000 procedures at 10 years to 78.0 per 1000 procedures at 5 years (follow-up was limited to 5 years at that site). CONCLUSION The 10-year cumulative probability of pregnancy after silicone rubber band and spring clip application is low but varies substantially by both clinical and demographic characteristics.
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Affiliation(s)
- H B Peterson
- Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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111
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Xia Z, Morales JC, Dunphy WG, Carpenter PB. Negative cell cycle regulation and DNA damage-inducible phosphorylation of the BRCT protein 53BP1. J Biol Chem 2001; 276:2708-18. [PMID: 11042216 DOI: 10.1074/jbc.m007665200] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In a screen designed to discover suppressors of mitotic catastrophe, we identified the Xenopus ortholog of 53BP1 (X53BP1), a BRCT protein previously identified in humans through its ability to bind the p53 tumor suppressor. X53BP1 transcripts are highly expressed in ovaries, and the protein interacts with Xp53 throughout the cell cycle in embryonic extracts. However, no interaction between X53BP1 and Xp53 can be detected in somatic cells, suggesting that the association between the two proteins may be developmentally regulated. X53BP1 is modified via phosphorylation in a DNA damage-dependent manner that correlates with the dispersal of X53BP1 into multiple foci throughout the nucleus in somatic cells. Thus, X53BP1 can be classified as a novel participant in the DNA damage response pathway. We demonstrate that X53BP1 and its human ortholog can serve as good substrates in vitro as well as in vivo for the ATM kinase. Collectively, our results reveal that 53BP1 plays an important role in the checkpoint response to DNA damage, possibly in collaboration with ATM.
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Affiliation(s)
- Z Xia
- Department of Biochemistry and Molecular Biology, University of Texas Health Sciences Center, Houston 77030, USA
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112
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Abstract
Although it is clear that soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor (SNARE) complex plays an essential role in synaptic vesicle fusion, the dynamics of SNARE assembly during vesicle fusion remain to be determined. In this report, we employ fluorescence resonance energy transfer technique to study the formation of SNARE complexes. Donor/acceptor pair variants of green fluorescent protein (GFP), cyan fluorescent protein (CFP), and yellow fluorescent protein (YFP) are fused with the N termini of SNAP-25 and synaptobrevin, respectively. In vitro assembly of SNARE core complex in the presence of syntaxin shows strong fluorescence resonance energy transfer (FRET) between the CFP-SNAP-25 and YFP-synaptobrevin. Under the same conditions, CFP fused to the C terminus of SNAP-25, and YFP- synaptobrevin have no FRET. Adenovirus-mediated gene transfer is used to express the fusion proteins in PC12 cells and cultured rat cerebellar granule cells. Strong FRET is associated with neurite membranes and vesicular structures in PC12 cells co-expressing CFP-SNAP-25 and YFP-synaptobrevin. In cultured rat cerebellar granule cells, FRET between CFP-SNAP-25 and YFP-synaptobrevin is mostly associated with sites presumed to be synaptic junctions. Neurosecretion in PC12 cells initiated by KCl depolarization leads to an increase in the extent of FRET. These results demonstrate that significant amounts of stable SNARE complex exist prior to evoked synaptic vesicle fusion and that the assembly of SNARE complex occurs during vesicle docking/priming stage. Moreover, it demonstrates that FRET can be used as an effective tool for investigating dynamic SNARE interactions during synaptic vesicle fusion.
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Affiliation(s)
- Z Xia
- Department of Pathology, the University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73190, USA
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113
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Cavanaugh JE, Ham J, Hetman M, Poser S, Yan C, Xia Z. Differential regulation of mitogen-activated protein kinases ERK1/2 and ERK5 by neurotrophins, neuronal activity, and cAMP in neurons. J Neurosci 2001; 21:434-43. [PMID: 11160424 PMCID: PMC6763829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
Activation of the extracellular signal-regulated kinase 1 (ERK1) and ERK2 by neurotrophins, neuronal activity, or cAMP has been strongly implicated in differentiation, survival, and adaptive responses of neurons during development and in the adult brain. Recently, a new member of the mitogen-activated protein (MAP) kinase family, ERK5, was discovered. Like ERK1 and ERK2, ERK5 is expressed in neurons, and ERK5 stimulation by epidermal growth factor is blocked by the MAP kinase/ERK kinase 1 (MEK1) inhibitors PD98059 and U0126. This suggests the interesting possibility that some of the functions attributed to ERK1/2 may be mediated by ERK5. However, the regulatory properties of ERK5 in primary cultured neurons have not been reported. Here we examined the regulation of ERK5 signaling in primary cultured cortical neurons. Our data demonstrate that, similar to ERK1/2, ERK5 is activated by neurotrophins including brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and NT-4. BDNF stimulation of ERK5 required the activity of MEK5. Surprisingly, ERK5 was not stimulated by cAMP or neuronal activity induced by glutamate or membrane depolarization. In contrast to ERK1/2, ERK5 strongly activated the transcriptional activity of myocyte enhancer factor 2C (MEF2C) in pheochromocytoma 12 (PC12) cells and was required for neurotrophin stimulation of MEF2C transcription in both PC12 cells and cortical neurons. Furthermore, ERK1/2, but not ERK5, induced transcription from Elk1 and the cAMP/ Ca(2+) response element in PC12 cells. Our data suggest that mechanisms for regulation of ERK5 and downstream transcriptional pathways regulated by ERK5 are distinct from those of ERK1/2 in neurons. Furthermore, ERK5 is the first MAP kinase identified whose activity is stimulated by neurotrophins but not by neuronal activity.
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Affiliation(s)
- J E Cavanaugh
- Departments of Environmental Health and Pharmacology, University of Washington, Seattle, Washington 98195-7234, USA
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114
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Quan GX, Mita K, Okano K, Shimada T, Ugajin N, Xia Z, Goto N, Kanke E, Kawasaki H. Isolation and expression of the ecdysteroid-inducible angiotensin-converting enzyme-related gene in wing discs of Bombyx mori. Insect Biochem Mol Biol 2001; 31:97-103. [PMID: 11102839 DOI: 10.1016/s0965-1748(00)00112-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We isolated a clone encoding a putative angiotensin-converting enzyme-related gene from the wing disc cDNA library of the silkworm, Bombyx mori (refer to as BmAcer). The predicted open reading frame encoded 648 amino acids with about 50% identities with the Drosophila melanogaster angiotensin-converting enzyme Ance and Acer. Northern analysis identified a 2.2-kilobase mRNA which was abundant in wing discs two days after the beginning of wandering. An accumulation of the transcript was observed approximately 2 h after 20-hydroxyecdysone (20E) exposure in vitro and was blocked slightly by a protein synthetic inhibitor. These data suggest that the transcription of the BmAcer gene is directly 20E-inducible.
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Affiliation(s)
- G X Quan
- Faculty of Agriculture, Utsunomiya University, 350 Mine, Utsunomiya, 321-8505, Tochigi, Japan
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115
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Abstract
Complementary DNA libraries from liver and ovary of an immature female channel catfish were screened with a homologous ERalpha cDNA probe. The hepatic library yielded two new channel catfish ER cDNAs that encode N-terminal ERalpha variants of different sizes. Relative to the catfish ERalpha (medium size; 581 residues) previously reported, these new cDNAs encode Long-ERalpha (36 residues longer) and Short-ERalpha (389 residues shorter). The 5'-end of Long-ERalpha cDNA is identical to that of Medium-ERalpha but has an additional 503-bp segment with an upstream, in-frame translation-start codon. Recombinant Long-ERalpha binds estrogen with high affinity (K(d) = 3. 4 nM), similar to that previously reported for Medium-ERalpha but lower than reported for catfish ERbeta. Short-ERalpha cDNA encodes a protein that lacks most of the receptor protein and does not bind estrogen. Northern hybridization confirmed the existence of multiple hepatic ERalpha RNAs that include the size range of the ERalpha cDNAs obtained from the libraries as well as additional sizes. Using primers for RT-PCR that target locations internal to the protein-coding sequence, we also established the presence of several ERalpha cDNA variants with in-frame insertions in the ligand-binding and DNA-binding domains and in-frame or out-of-frame deletions in the ligand-binding domain. These internal variants showed patterns of expression that differed between the ovary and liver. Further, the ovarian library yielded a full-length, ERalpha antisense cDNA containing a poly(A) signal and tail. A limited survey of histological preparations from juvenile catfish by in situ hybridization using directionally synthesized cRNA probes also suggested the expression of ERalpha antisense RNA in a tissue-specific manner. In conclusion, channel catfish seemingly have three broad classes of ERalpha mRNA variants: those encoding N-terminal truncated variants, those encoding internal variants (including C-terminal truncated variants), and antisense mRNA. The sense variants may encode functional ERalpha or related proteins that modulate ERalpha or ERbeta activity. The existence of ER antisense mRNA is reported in this study for the first time. Its role may be to participate in the regulation of ER gene expression.
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Affiliation(s)
- R Patiño
- Texas Cooperative Fish & Wildlife Research Unit, Texas Tech University, Lubbock, Texas 79409-2120, USA.
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116
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Li G, Shi Z, Jia H, Ju J, Wang X, Xia Z, Qin L, Ge C, Xu Y, Cheng L, Chen P, Yuan G. A clinical investigation on garlicin injectio for treatment of unstable angina pectoris and its actions on plasma endothelin and blood sugar levels. J TRADIT CHIN MED 2000; 20:243-6. [PMID: 11263272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
To investigate the therapeutic effects and mechanisms of garlicin for treatment of unstable angina pectoris (UAP), garlicin injectio was intravenously dripped 60 mg/day in 34 cases for 10 days. Nitroglycerine was used in 21 cases of the control group. The results showed that the total effective rates in improving symptoms and electrocardiogram after garlicin treatment were respectively 82% and 62%, and that the plasma endothelin and blood sugar levels were markedly lowered in cases with hyperglycemia.
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Affiliation(s)
- G Li
- TCM Department of Cardio-renal Diseases, Sino-Japanese Friendship Hospital, Beijing 100029
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117
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Shi X, Xia Z, Fang J. [Effects of Salvia miltiorrhiza compound injection on serum endothelin, prostaglandin I2/thromboxane A2 ratio alteration following myocardial ischemia-reperfusion in patients undergoing intracardiac surgery]. Zhongguo Zhong Xi Yi Jie He Za Zhi 2000; 20:896-8. [PMID: 11938858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
OBJECTIVE To investigate the effects of Salvia miltiorrhiza compound injection (SMCI) on serum endothelin (ET), prostaglandin I2(PGI2), thromboxane A2(TXA2), and PGI2/TXA2 ratio following myocardial ischemia-reperfusion in patients undergoing intracardiac surgery. METHODS Twenty patients, scheduled for selective surgery, were randomly divided into the SMCI group (group A, 10 cases) and the control group (group B, 10 cases). SMCI 200 mg/kg was given intravenously in group A before starting the operation and at the time of rewarming respectively, and equivalent volumes of normal saline were administered to group B. The central venous blood samples were collected to measure the serum concentration of ET, PGI2, TXA2, and PGI2/TXA2 ratio. RESULTS ET significantly reduced, while PGI2 and TXA2 obviously raised in both groups at the beginning (T1) of extracorporeal cardiopulmonary bypass (CPB) (P < 0.05). After cardiac ischemia-reperfusion, ET in group B increased rapidly and significantly (P < 0.05) and evidently higher than the corresponding value in group A 30 min after reperfusion (T3) till 24 hrs after reperfusion (T5). During reperfusion, PGI2 and TXA2 in group A decreased more rapidly than that of group B, while group A maintained higher PGI2/TXA2 ratio than that of group B. At T5, PGI2 and TXA2 in group A were significantly lower than those in group B, while PGI2/TXA2 ratio was higher than that in group B (P < 0.05). The serum ET level was obviously negatively correlated to PGI2/TXA2 ratio. The postoperative cardiac function recovered much better in group A than in that group B. CONCLUSION SMCI can significantly reduce serum ET level, raise PGI2/TXA2 ratio, thus facilitate the postoperative cardiac function recovery following intracardiac surgery under CPB.
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Affiliation(s)
- X Shi
- First Affiliated Hospital of Hubei Medical University, Wuhan 430060
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118
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Nishida T, Meyns B, Zietkiewicz M, Perek B, Xia Z, Goebel C, Reul H, Flameng W. The effect of sudden failure of a rotary blood pump on left ventricular performance in normal and failing hearts. Artif Organs 2000; 24:893-8. [PMID: 11119078 DOI: 10.1046/j.1525-1594.2000.06549.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We investigated the hemodynamic effect of regurgitation (or back-flow) due to sudden failure of a rotary blood pump (diagonal pump). Seven healthy sheep (Group C) and 7 with chronic heart failure (Group F) were studied. Chronic heart failure was obtained by intracoronary injection of microspheres several weeks earlier. Left ventricular function and ventricular efficacy were assessed by the pressure-volume relationship. The back-flow through the stopped pump was significantly lower in Group F (2.3 +/- 0.34 L/min) than in Group C (2.8 +/- 0.33 L/min). Mean aortic blood pressure dropped significantly from 68.3 +/- 9.65 to 61.9 +/- 9.75 mm Hg in Group C and from 62.5 +/- 9.12 to 51.5 +/- 9.08 in Group F but remained stable during the 15 min period of pump stop. Parameters of left ventricular contractility (preload recruitable stroke work) dropped significantly in both groups, remained stable during the pump stop, and returned to baseline values 30 min after the end of back-flow. The ventricular efficacy (in terms of energy transfer) was tolerant against this acute volume overload even in the failing hearts. Sudden pump failure of a rotary blood pump leads to an acute depression of the hemodynamic state and myocardial contractility. However, this depression remained stable over 15 min, did not lead to further deterioration of the animals, and was completely reversible.
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Abstract
The induction of yeast Saccharomyces cerevisiae gene PHO5 expression is mediated by transcriptional factors PHO2 and PHO4. PHO4 protein has been reported to be phosphorylated and inactivated by a cyclin-CDK (cyclin-dependent kinase) complex, PHO80-PHO85. We report here that PHO2 can also be phosphorylated. A Ser-230 to Ala mutation in the consensus sequence (SPIK) recognized by cdc2/CDC28-related kinase in PHO2 protein led to complete loss of its ability to activate the transcription of PHO5 gene. Further investigation showed that the Pro-231 to Ser mutation inactivated PHO2 protein as well, whereas the Ser-230 to Asp mutation did not affect PHO2 activity. Since the PHO2 Asp-230 mutant mimics Ser-230-phosphorylated PHO2, we postulate that only phosphorylated PHO2 protein could activate the transcription of PHO5 gene. Two hybrid assays showed that yeast CDC28 could interact with PHO2. CDC28 immunoprecipitate derived from the YPH499 strain grown under low phosphate conditions phosphorylated GST-PHO2 in vitro. A phosphate switch regulates the transcriptional activation activity of PHO2, and mutations of the (SPIK) site affect the transcriptional activation activity of PHO2 and the interaction between PHO2 and PHO4. BIAcore(R) analysis indicated that the negative charge in residue 230 of PHO2 was sufficient to help PHO2 interact with PHO4 in vitro.
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Affiliation(s)
- C Liu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry, Chinese Academy of Sciences, Shanghai 200031, People's Republic of China
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120
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Abstract
Synaptosomal associated protein of 25 kDa (SNAP-25) is a member of the SNARE protein complex that has been implicated in synaptic vesicle docking and fusion. In this report, we have generated SNAP-25 mutants and assayed their functions in SNARE complex formation and glutamate release from cultured rat cerebellar granule cells. In vitro binding studies show that a deletion mutant lacking the C-terminal 181-206 amino acid sequence inhibits the formation of the SNARE core complex. Additional deletion of an N-terminal 1-31 amino acid sequence abolished this inhibitory activity. Adenovirus-mediated gene transfer is used to overexpress wild-type and mutant SNAP-25 in cerebellar granule cells. Neurons overexpressing the wild-type protein show slight reductions in glutamate release, ranging from 10 to 15% in both the developing and mature granule cells. A 30-35% inhibition is obtained with the C-terminal deletion mutant, and the inhibitory effect is abolished in the N- and C-terminal double deletion mutant. These results demonstrate that the SNARE core complex exists in a dynamic and reversible state, and the formation of the core complex is necessary for neurotransmitter release in neurons.
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Affiliation(s)
- Y Yang
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73190, USA
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121
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Abstract
Recent evidence indicates that phosphatidylinositol 3-kinase (PI3K) is a central regulator of mitosis, apoptosis and oncogenesis. Nevertheless, the mechanisms by which PI3K regulates proliferation are not well characterized. Mitogens stimulate entry into the cell cycle by inducing the expression of immediate early genes (IEGs) that in turn trigger the expression of G(1) cyclins. Here we describe a novel PI3K- regulated transcriptional cascade that is critical for mitogen regulation of the IEG, c-fos. We show that PI3K activates gene expression by transactivating SRF-dependent transcription independently of the previously described Rho and ETS TCF pathways. PI3K-stimulated cell cycle progression requires transactivation of SRF and expression of dominant- negative PI3K blocks mitogen-stimulated cell cycle progression. Furthermore, dominant-interfering SRF mutants attenuate mitogen-stimulated cell cycle progression, but are without effect on MEK-stimulated cell cycle entry. Moreover, expression of constitutively active SRF is sufficient for cell cycle entry. Thus, we delineate a novel SRF-dependent mitogenic cascade that is critical for PI3K- and growth factor-mediated cell cycle progression.
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Affiliation(s)
- S Poser
- Department of Pharmacology, School of Medicine, University of Washington, Seattle, 98195, USA
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122
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Yawn BP, Xia Z, Edmonson L, Jacobson RM, Jacobsen SJ. Barriers to immunization in a relatively affluent community. J Am Board Fam Pract 2000; 13:325-32. [PMID: 11001002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
Abstract
BACKGROUND Although Healthy People 2000 calls for the complete immunization of at least 90% of children by age 20 months, few communities can claim such success. We wanted to determine the parent-reported barriers associated with underimmunization of infants in a relatively affluent midwestern population. METHODS We undertook a case-control study of a population-based sample of parents and guardians of children who were either fully immunized or underimmunized at 20 months of age in Olmsted County, Minn. RESULTS In this study, 596 of 1,216 parents (46%) of both immunized and underimmunized children participated. Of these participants, 281 (47%) reported barriers to immunizations, but only 15 (3%) reported major barriers. Whereas the most commonly reported barriers were barriers of inconvenience (waiting too long, inconvenient office hours), only delays caused by a sick child, fear of reactions, trouble remembering an appointment, not knowing when the next shot was due, and transportation problems were significantly associated with underimmunization when controlling for demographic factors. Fear of reactions, sick child delays, and not knowing when the next shot was due had the highest attributable risk for underimmunization. Taken together, parent-reported barriers and demographic factors explained less than 30% of the underimmunization status of children. Parents' most common recommendations for improving immunization status were the use of a recall or reminder system and a single unified schedule for immunizations. CONCLUSIONS In this relatively affluent community, barriers to immunization were commonly reported but few (fear of reactions, sick child delays, and not knowing when the next shot was due) were associated with underimmunization. The types of barriers reported were similar to those reported in other communities, but unlike many populations studied, cost was not reported as an important barrier.
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Affiliation(s)
- B P Yawn
- Olmsted Medical Center, Department of Research, Rochester, Minn 55904, USA
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123
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Namgung U, Xia Z. Arsenite-induced apoptosis in cortical neurons is mediated by c-Jun N-terminal protein kinase 3 and p38 mitogen-activated protein kinase. J Neurosci 2000; 20:6442-51. [PMID: 10964950 PMCID: PMC6772983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
c-Jun N-terminal protein kinase (JNK) and p38 mitogen-activated protein kinase are activated by stress and are implicated in regulation of apoptosis in several tissues. However, their contribution to stress-induced apoptosis in CNS neurons is not well defined. Here we investigated the role of JNK and p38 in cortical neuron apoptosis caused by sodium arsenite treatment. Sodium arsenite is an environmental toxicant that causes developmental defects in the CNS. Treatment of cortical neurons with sodium arsenite activated p38 and JNK3 but not JNK1 or JNK2. It also induced c-Jun phosphorylation. Furthermore, sodium arsenite induced cortical neuron apoptosis. This apoptosis was attenuated by SB203580, an inhibitor of p38, and by CEP-1347, an inhibitor of JNK activation. Expression of dominant-interfering mutants of the JNK or p38 pathways inhibited apoptosis induced by arsenite, whereas expression of constitutive active mutants for either pathway induced apoptosis. Moreover, the caspase inhibitor zVAD-fluoromethylketone as well as expression of bcl-2 or bcl-xL inhibited cortical neuron apoptosis induced by arsenite or by constitutive activation of JNK or p38. These data indicate that both JNK and p38 contribute to arsenite-induced apoptosis in primary CNS neurons, and this apoptosis requires the bcl-2-caspase pathway. This is the first evidence that a specific JNK isoform is differentially activated by stress and contributes to neuronal apoptosis.
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Affiliation(s)
- U Namgung
- Toxicology Program, Department of Environmental Health, and Graduate Programs in Neurobiology and Behavior and Molecular and Cell Biology, University of Washington, Seattle, Washington 98195, USA
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Wong ST, Trinh K, Hacker B, Chan GC, Lowe G, Gaggar A, Xia Z, Gold GH, Storm DR. Disruption of the type III adenylyl cyclase gene leads to peripheral and behavioral anosmia in transgenic mice. Neuron 2000; 27:487-97. [PMID: 11055432 DOI: 10.1016/s0896-6273(00)00060-x] [Citation(s) in RCA: 319] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Cyclic nucleotide-gated ion channels in olfactory sensory neurons (OSNs) are hypothesized to play a critical role in olfaction. However, it has not been demonstrated that the cAMP signaling is required for olfactory-based behavioral responses, and the contributions of specific adenylyl cyclases to olfaction have not been defined. Here, we report the presence of adenylyl cyclases 2, 3, and 4 in olfactory cilia. To evaluate the role of AC3 in olfactory responses, we disrupted the gene for AC3 in mice. Interestingly, electroolfactogram (EOG) responses stimulated by either cAMP- or inositol 1,4,5-triphosphate- (IP3-) inducing odorants were completely ablated in AC3 mutants, despite the presence of AC2 and AC4 in olfactory cilia. Furthermore, AC3 mutants failed several olfaction-based behavioral tests, indicating that AC3 and cAMP signaling are critical for olfactory-dependent behavior.
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Affiliation(s)
- S T Wong
- Department of Pharmacology, University of Washington, Seattle 98195, USA
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125
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Xia Z, Sorock GS, Zhu J, Courtney TK, Fu H, Liang Y, Christiani DC. Fatal occupational injuries in the construction industry of a new development area in east China, 1991 to 1997. AIHAJ 2000; 61:733-7. [PMID: 11071426 DOI: 10.1080/15298660008984584] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Two hundred thirty-five work-related deaths occurred in the construction industry in a new economic development area in eastern China between 1991 and 1997. These fatalities represented 55% of all occupational deaths. The average annual mortality rate was 51.5 per 100,000 construction workers. Falls were the leading cause of death (46.4%). Falls, collisions, struck by/against something, electrocutions, and excavation cave-ins were the main fatality antecedents, accounting for nearly 93.6% of all fatalities. The most common antecedents for incidents with multiple fatalities were falls, crane-related events, poisoning, and fire. These categories of antecedents were similar to those encountered in the construction industry in the United States. These data suggest that organizations need to focus on these event types when planning their prevention activities. Moreover, improved surveillance systems including computerized databases with narrative descriptions of injury events, antecedent factors, and person-time at-risk data are needed to target interventions more precisely.
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Affiliation(s)
- Z Xia
- School of Public Health, Shanghai Medical University, PR China
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126
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Abstract
We have recently reported that the tricyclic antidepressants (TCAs) imipramine, clomipramine, and citalopram induce apoptosis in human peripheral lymphocytes. This system is well suited for studies on the pathophysiology/physiology of apoptosis regulation. Apoptosis was determined using both DNA gel electrophoresis and flow cytometric analysis. TCA-induced apoptosis in lymphocytes was monitored in the presence of the protein synthesis inhibitor cycloheximide (CHX), the RNA synthesis inhibitor actinomycin D (Act D), the antioxidant reduced glutathione (GSH), the nuclease inhibitor aurintricarboxylic acid (ATA), the cytokine interleukin-2 (IL-2), and the immunostimulator linomide. CHX and Act D failed to prevent and actually enhanced TCA-induced apoptosis in lymphocytes, indicating that protein and RNA syntheses are not required for this process. Exogenous IL-2, GSH, and ATA protected the lymphocytes from apoptosis induced by TCAs in a dose-dependent manner, whereas linomide had no effect on TCA-induced apoptosis under our in vitro conditions. Our data demonstrate that TCA-induced apoptosis in human lymphocytes shares many common features with other stimuli-induced apoptotic processes.
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Affiliation(s)
- Z Xia
- Department of Biochemistry, Wallenberg Laboratory, Stockholm University, Sweden
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127
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Xia Z, Bergstrand A, DePierre JW, Nässberger L. The antidepressants imipramine, clomipramine, and citalopram induce apoptosis in human acute myeloid leukemia HL-60 cells via caspase-3 activation. J Biochem Mol Toxicol 2000; 13:338-47. [PMID: 10487422 DOI: 10.1002/(sici)1099-0461(1999)13:6<338::aid-jbt8>3.0.co;2-7] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Some widely used antidepressants such as imipramine, clomipramine, and citalopram have been found to possess antineoplastic effects. In the present study, these compounds were found to induce apoptotic cell death in human acute myeloid leukemia HL-60 cells. Apoptosis induced by the antidepressants was identified by electron microscopy and conventional agarose gel electrophoresis and was quantitated by propodium iodide staining and the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) via flow cytometry. Treatment with apoptosis-inducing concentrations of the antidepressants (80 microM imipramine, 35 microM clomipramine, or 220 microM citalopram) caused induction of caspase-3/caspase-3-like activity, which was monitored by the cleavage of poly(ADP-ribose) polymerase (PARP), the loss of the 32 kD caspase-3 (CPP32) precursor, and the cleavage of the fluorescent CPP32-like substrate PhiPhiLux. Pretreatment with a potent caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl-ketone (zVAD-fmk) inhibited antidepressant-induced CPP32/CPP32-like activity and apoptosis. Furthermore, activation of caspase induced by the antidepressants was preceded by the hypergeneration of intracellular reactive oxygen species (ROS). These results suggested that the antidepressants may induce apoptosis via a caspase-3-dependent pathway, and induction of apoptosis by the antidepressants may provide a clue for the mechanism of their antineoplastic effects.
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Affiliation(s)
- Z Xia
- Department of Biochemistry, Wallenberg Laboratory, Stockholm University, Sweden.
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128
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Xia Z, Shen H, Chen Y. [Alterations of anabolism in hepatic cells of burned rats measured by (13)C NMR spectroscopy]. Zhonghua Shao Shang Za Zhi 2000; 16:210-4. [PMID: 11876872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
OBJECTIVE To introduce a safe and specific approach of (13)C NMR spectroscopy and investigate the alterations in hepatic anabolism functions including pyruvate recycling, gluconeogenesis and anaplerosis in severely burned rats. METHODS Adult Spreque -- Dawley (SD) rats were catheterized arteriovenously via left carotid and right external jugular vein under inhalation anesthesia and were randomly divided into burn group (B) and sham burn group (S). Fluid resuscitation started 20 min postburn. Sodium [1, 2, 3 -- (13)C] propionate (SP) was intravenously administered as a tracer at 72 postburn hour (PBH). (13)C NMR spectroscopy of extracted plasma and liver, arterial blood pressure, heart rate and plasma glucose and sodium levels were measured. Metabolic parameters were calculated using a mathematical model of input -- output matrix to feed the tricarboxylic acid cycle. RESULTS When compared to those in C group, burned rats exhibited a lower arterial blood pressure, but normal blood glucose at 72 PBH. Intravenous SP infusion did not alter MAP, heart rate and plasma sodium. The form of blood sugar labeled by (13)C isotopomer was in excellent agreement with that from liver. After continuous infusion of SP for 45 mins, SP could reach metabolic steady status. The hepatic cellular gluconeogenesis, anaplerosis and the carbon flow rate in pyruvate recycling significantly increased in B group when comparing to those in C group. But the carbon flow rate in Kreb's cycle decreased relatively, and hepatic pools of alanine, glutamic acid and glutamine were enlarged obviously in burned rats relative to sham burn group. CONCLUSION These data suggested that intravenous infusion of SP would not alter MAP, heart rate and blood sodium. Forty -- five mins after the intravenous infusion, the tracer could reach metabolic steady status. The form of blood sugar labeled by (13)C could represent that of hepatic sugar. Seventy -- two hours after major burns, there were increased hepatic anaplerosis, gluconeogenesis and pyruvate recycling and a correspondent increased utilization ratio of blood sugar by peripheral tissue.
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Affiliation(s)
- Z Xia
- Department of Burns, Changhai Hospital, The Second Military Medical University, Shanghai, 200433, P. R. China
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129
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Yoshioka K, Domi M, Wang S, Li Y, Xia Z, Oyamada T, Yoshikawa H, Yoshikawa T. Hepatic ceroid-lipofuscinosis in enzootic cardiomyopathy of sika deer (Cervus nippon temminck). J Comp Pathol 2000; 123:67-71. [PMID: 10906259 DOI: 10.1053/jcpa.2000.0387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Hepatic lesions in 25 sika deer (Cervus nippon Temminck) aged 1-15 days, affected by selenium-deficiency cardiomyopathy, were examined histopathologically. Characteristic pathological findings, induced by stagnation of the plasma proteins of the cytoplasm, consisted of vacuolar degeneration of hepatocytes, formation of hyalin droplets, and ceroid-lipofuscinosis. Electron microscopically, these changes were closely associated with degeneration of the endoplasmic reticulum and mitochondria. Peroxisomes, which were observed around the vacuoles, were regarded as a reactive result of membrane disturbance caused by a decrease in glutathione peroxidase (GSH-Px)
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Affiliation(s)
- K Yoshioka
- Department of Veterinary Pathology, School of Veterinary Medicine and Animal Sciences, Kitasato University, Towada, Aomori 034, Japan
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130
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Li B, Xia Z, Chen D. [Combined treatment of pseudohermaphroditism]. Zhonghua Zheng Xing Wai Ke Za Zhi 2000; 16:206-7. [PMID: 11593672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
OBJECTIVE To diagnose and treat female pseudohermaphroditism caused by 21-hydroxylase deficiencies. METHODS Four female patients with 21-hydroxylase deficiencies have received combined treatment of reconstructive surgery and supplementary glucocorticoid in our hospital since 1990. RESULTS The patients obtained a female external genitalia through the operation. Various symptoms resulted from 21-hydroxylase deficiency were improved with glucocorticoid therapy. CONCLUSION A satisfying result can be achieved for pseudohermaphroditism by combination of surgery and medicine.
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Affiliation(s)
- B Li
- Department of Plastic Surgery, Quanzhou First Hospital, Quanzhou 362000, PR China
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131
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Xia C, Xia Z. Nuclear volume estimation using different sampling, measurement and calculation methods. Anal Quant Cytol Histol 2000; 22:258-62. [PMID: 10872044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
OBJECTIVE To study the reliability of volume parameter measured on tissue sections through different sampling, measurement and calculation methods. STUDY DESIGN The largest nuclear profile image under a 100x, NA 1.30 oil immersion objective of primary spermatocytes and spherical spermatoblasts on 11-micron-thick seminiferous tubule sections and tissue images, under a 20x objective, on 4-micron sections were captured. Their volumes were measured and calculated by the five methods provided by the Technology for Image and Graphics Engineering Research cell image analysis system. RESULTS The nuclear volumes obtained by nucleator and area equivalent diameter on the largest nuclear profile image were almost the same, including binary images by automated and manual interactive nucleator and grey scale images only by the latter. Nuclear volumes, calculated by random Feret diameter and equivalent diameter of the perimeter, the minimal circumference of the largest nuclear profile binary image, were obviously larger than those of the nucleator and area equivalent diameter. Due to different-sized nuclear slices entrapped in the same section, those nuclear volumes from the seminiferous tubule tissue images were strikingly lower than that of the largest nuclei profile image. The shape factors of primary spermatocytes and spherical spermatoblast nuclei under 100x and 20x objectives were approximately the same. CONCLUSION The sample preparation, sampling methods and calculation formulas suitable to nuclear form are necessary to obtain reproducible volume parameters.
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Affiliation(s)
- C Xia
- Department of Histology and Embryology, Medical College, Jinan University, Guangzhou, People's Republic of China.
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132
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Xia Z, Nguyen BD, La Mar GN. The use of chemical shift temperature gradients to establish the paramagnetic susceptibility tensor orientation: implication for structure determination/refinement in paramagnetic metalloproteins. J Biomol NMR 2000; 17:167-174. [PMID: 10921780 DOI: 10.1023/a:1008309121949] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The use of dipolar shifts as important constraints in refining molecular structure of paramagnetic metalloproteins by solution NMR is now well established. A crucial initial step in this procedure is the determination of the orientation. of the anisotropic paramagnetic susceptibility tensor in the molecular frame which is generated interactively with the structure refinement. The use of dipolar shifts as constraints demands knowledge of the diamagnetic shift. which, however, is very often not directly and easily accessible. We demonstrate that temperature gradients of dipolar shifts can serve as alternative constraints for determining the orientation of the magnetic axes, thereby eliminating the need to estimate the diamagnetic shifts. This approach is tested on low-spin, ferric sperm whale cyanometmyoglobin by determining the orientation, anisotropies and anisotropy temperature gradients by the alternate routes of using dipolar shifts and dipolar shift gradients as constraints. The alternate routes ultimately lead to very similar orientation of the magnetic axes, magnetic anisotropies and magnetic anisotropy temperature gradients which, by inference, would lead to an equally valid description of the molecular structure. It is expected that the use of the dipolar shift temperature gradients, rather than the dipolar shifts directly, as constraints will provide an accurate shortcut in a solution structure determination of a paramagnetic metalloprotein.
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Affiliation(s)
- Z Xia
- Department of Chemistry, University of California, Davis 95616, USA
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133
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Gu Y, Chen W, Xia Z. Molecular modeling of the interactions of trichosanthin with four substrate analogs. J Protein Chem 2000; 19:291-7. [PMID: 11043934 DOI: 10.1023/a:1007047413373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Trichosanthin (TCS) is a ribosome-inactivating protein (RIP) that possesses N-glycosidase activity. It inactivates ribosomes and arrests protein synthesis by removing a specific adenine from 28S rRNA. A molecular dynamics simulated annealing method was applied to study the binding modes of TCS with substrate analogs, three oligonucleotides GAG, GAGA, and CGAGAG, based on the crystal structures of the stable complexes of TCS with NADPH and with the reaction product adenine. A water molecule proposed to be responsible for hydrolyzing the N-glycosidic bond was included in the model. All the oligoribonucleotides can dock into the active cleft of TCS without unfavorable contacts. The interaction energies between TCS and the three oligonucleotides were calculated. The interactions of TCS with NADH were also studied by a molecular dynamics simulated annealing method. The interaction energy between NADH and TCS was compared with that between NADPH and TCS, showing that the lack of 2'-phosphate group leads to an energy rise of 20 kcal/mol.
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Affiliation(s)
- Y Gu
- State Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences
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134
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Hetman M, Cavanaugh JE, Kimelman D, Xia Z. Role of glycogen synthase kinase-3beta in neuronal apoptosis induced by trophic withdrawal. J Neurosci 2000; 20:2567-74. [PMID: 10729337 PMCID: PMC6772233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
Glycogen synthase kinase-3beta (GSK3beta) activity is negatively regulated by several signal transduction cascades that protect neurons against apoptosis, including the phosphatidylinositol-3 kinase (PI-3 kinase) pathway. This suggests the interesting possibility that activation of GSK3beta may contribute to neuronal apoptosis. Consequently, we evaluated the role of GSK3beta in apoptosis in cultured cortical neurons induced by trophic factor withdrawal or by PI-3 kinase inhibition. Neurons were subjected to several apoptotic paradigms, including serum deprivation, serum deprivation combined with exposure to NMDA receptor antagonists, or treatment with PI-3 kinase inhibitors. These treatments all led to stimulation of GSK3beta activity in cortical neurons, which preceded the induction of apoptosis. Expression of an inhibitory GSK3beta binding protein or a dominant interfering form of GSK3beta reduced neuronal apoptosis, suggesting that GSK3beta contributes to trophic factor withdrawal-induced apoptosis. Furthermore, overexpression of GSK3beta in neurons increased apoptosis, indicating that activation of this enzyme is sufficient to trigger programmed cell death. Although destabilization of beta-catenin is an important physiological effect of GSK3beta activation, expression of a mutant beta-catenin that is not destabilized by GSK3beta did not protect against apoptosis. We conclude that inhibition of GSK3beta is one of the mechanisms by which PI-3 kinase activation protects neurons from programmed cell death.
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Affiliation(s)
- M Hetman
- Toxicology Program in the Department of Environmental Health, University of Washington, Seattle, Washington 98195-7234, USA
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135
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Xia Z, Gale WL, Chang X, Langenau D, Patiño R, Maule AG, Densmore LD. Phylogenetic sequence analysis, recombinant expression, and tissue distribution of a channel catfish estrogen receptor beta. Gen Comp Endocrinol 2000; 118:139-49. [PMID: 10753576 DOI: 10.1006/gcen.1999.7447] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
An estrogen receptor beta (ERbeta) cDNA fragment was amplified by RT-PCR of total RNA extracted from liver and ovary of immature channel catfish. This cDNA fragment was used to screen an ovarian cDNA library made from an immature female fish. A clone was obtained that contained an open reading frame encoding a 575-amino-acid protein with a deduced molecular weight of 63.9 kDa. Maximum parsimony and Neighbor Joining analyses were used to generate a phylogenetic classification of channel catfish ERbeta on the basis of 25 full-length teleost and tetrapod ER sequences. The consensus tree obtained indicated the existence of two major vertebrate ER subtypes, alpha and beta. Within each subtype, and in accordance with established phylogenetic relationships, teleost and tetrapod ER were monophyletic confirming the results of a previous analysis (Z. Xia et al., 1999, Gen. Comp. Endocrinol. 113, 360-368). Extracts of COS-7 cells transfected with channel catfish ERbeta cDNA bound estrogen with high affinity (K(d) = 0.21 nM) and specificity. The affinity of channel catfish ERbeta for estrogen was higher than previously reported for channel catfish ERalpha. As determined by qualitative RT-PCR, the tissue distributions of ERalpha and ERbeta were similar but not identical. Both ER subtypes were present in ovary and testis. ERalpha was found in all other tissues examined from juvenile and mature fish of both sexes. ERbeta was also found in most tissues except, in most cases, whole blood and head kidney. Interestingly, the pattern of expression of ER subtypes in head kidney always corresponded to the pattern in whole blood. In conclusion, we isolated a channel catfish ERbeta with ligand-binding affinity and tissue expression patterns different from ERalpha. Also, we confirmed the validity of our previously proposed general classification scheme for vertebrate ER into alpha and beta subtypes and within each subtype, into teleost and tetrapod clades.
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Affiliation(s)
- Z Xia
- Texas Cooperative Fish & Wildlife Research Unit, Texas Tech University, Lubbock, Texas 79409-2120, USA
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Xia Z, Ying G, Hansson AL, Karlsson H, Xie Y, Bergstrand A, DePierre JW, Nässberger L. Antidepressant-induced lipidosis with special reference to tricyclic compounds. Prog Neurobiol 2000; 60:501-12. [PMID: 10739086 DOI: 10.1016/s0301-0082(99)00036-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cationic amphiphilic drugs, in general, induce phospholipid disturbances. Tricyclic, as well as other antidepressants belong to this group. In experimental animals, antidepressants induce lipid storage disorders in cells of most organs, a so-called generalized phospholipidosis. This disorder is conveniently detected by electron microscopic examination revealing myelin figures. Myelin figures or myeloid bodies are subcellular organelles containing unicentric lamellar layers. The lipidotic induction potency during in vivo is related to the apolarity of the compound. Metabolism of phospholipids takes place within the cell continuously. Several underlying mechanisms may be responsible for the induction of the phospholipid disturbance. For instance, it has been suggested that the compounds bind to phospholipids and such binding may alter the phospholipid's suitability as a substrate for phospholipases. Free TCA or metabolites thereof may also inhibit phospholipases directly, as has been demonstrated for sphingomyelinase in glioma and neuroblastoma cells. Both these mechanisms might result in phospholipidosis. Interaction between drug and phospholipid bilayer has been investigated by nuclear magnetic resonance technique. There seems to be large differences in the sensitivities amongst different organs. Steroid-producing cells of the adrenal cortex, testis and ovaries are in particular susceptible to drug-induced lipidosis. The so-called foam cells are lung macrophages located in the interstitium which become densely packed with myelin figures during TCA exposure. It requires about 3-6 weeks of treatment to develop this converted cell. In cell cultures however, phospholipidosis is demonstrated already after 24 h only. It appears that the cells that undergo TCA-induced lipidosis may recover after withdrawal of the drug. The time required to achieve complete recovery ranges from 3-4 weeks to several months, depending on the organ affected. Little is known about the functional significance of lipidosis. Even if TCA and other antidepressants show other effects, it has not been possible to exclusively relate it to phospholipidosis. However, few attempts have been made to correlate the physiological effects of TCAs in experimental animals to the morphological changes associated with phospholipidosis. There is an increasing evidence however, that cationic amphiphilic drugs may have effects on immune function, signal transduction and receptor-mediated events, effects that to some extent might be related to disturbances in phospholipid metabolism.
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Affiliation(s)
- Z Xia
- Department of Biochemistry, Stockholm University, Sweden
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137
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Fan C, Shi K, Chen S, Xia Z. [Detection of human cytomegalovirus by PCR in patients with gastrointestinal disease]. Hunan Yi Ke Da Xue Xue Bao 2000; 23:229-31. [PMID: 10681744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Human cytomegalovirus (HCMV) genomes was detected by PCR in 51 patients' biopsy or operation specimens with gastrointestinal disease. The positive rate was 9.80%. At the same time, 41 patients' serum HCMV-IgM was detected by indirect immunofluorescence assay (IFA); the positive rate was 46.34%. Patients with cancer and colitis exhibited a higher HCMV infection rate than those without cancer and colitis. The results suggest that PCR is sensitive and specific in detection of gastrointestinal HCMV infection, and the examination of biopsy or surgical specimen is superior than that of IFA of serum HMCV-IgG.
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Affiliation(s)
- C Fan
- Department of Microbiology, Hunan Medical University, Changsha
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138
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Abstract
A number of clinical studies have suggested that radiant heat improves the healing of selected acute and chronic wounds. The purpose of this study was to investigate in vitro the effect of intermittent radiant heating on the growth of human skin fibroblasts using a radiant heat-producing dressing with a designated temperature of 38 degrees C. In initial experiments cells were seeded in six well-plates, maintained in culture at 33-34 degrees C, and warmed daily for three cycles of 1 hour with 1.5 hour intervals. Changes in cell growth and metabolism were determined in sets of triplicate wells by cell counts and a colorimetric assay before and after one week's treatment. After eight days the number of cells in the radiant heat-treated group was 30% higher and the metabolic activity 47%- 90% higher than in the control group. In quiescent fibroblasts which had been maintained for four weeks in low-serum medium, the warming regime completely prevented the decrease in cell number observed in control cells. Our findings suggest that the stimulation of cell proliferation induced by intermittent heating in vitro may indicate a possible mechanism contributing to in vivo effects.
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Affiliation(s)
- Z Xia
- Wound Healing Institutea, Churchill Hospital, Oxford, UK
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139
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Xia Z, Liu Y, Jiao H. [Research on the parameters of Mark V injector]. Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 2000; 17:114-6. [PMID: 10879208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
This study sought to correctly preset the parameters of Mark v injection. The emphasis was laid on the flow rate in that, it ought to be set more carefully and more accurately for ensuring success in angiography. The authors analyzed the influential factors of flow rate and the relationship between flow rate and pressure limiting and hence proposed a set of typical presetting injection parameters. Experimental results demonstrated that with the contrast media concentration around 75%, high quality images could be obtained by setting the pressure limiting within 2068-5515 kPa.
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Affiliation(s)
- Z Xia
- First Affiliated Hospital, West China University of Medical Sciences, Chengdu
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140
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Wang G, Yu B, Xia Z. [Myocardial apoptosis induced by delayed fluid resuscitation in a burned rat model]. Zhonghua Shao Shang Za Zhi 2000; 16:40-2. [PMID: 11876842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
OBJECTIVE To explore the possibility and the mechanism of myocardial apoptosis induced by delayed fluid resuscitation in a burned rat model and its relationship with nitric oxide (NO) and oxygen-derived free radicals. METHODS In a rat model with 30% III degree burn, the genomic DNA of the myocardial tissue was detected with ApoAlert(TMLM)-PCR Ladder Assay Kit and visualized with agarose gel electrophoresis. Meanwhile, the NO and the content of unsaturated fatty acids were measured. RESULTS In rats receiving delayed fluid resuscitation following burn, the myocardial genomic DNA exhibited DNA ladder-index of apoptosis, and the contents of myocardial NO and unsaturated fatty acid were much lower than those in rats receiving immediate resuscitation (P < 0.05). CONCLUSION The myocardial tissue undergoes apoptosis in burned rats receiving delayed fluid resuscitation, and the decreased NO and the production of oxygen-derived free radicals are also observed in this process.
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Affiliation(s)
- G Wang
- Burns Center, Changhai Hospital, Second Military Medical University, Shanghai 200433, China
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141
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Nguyen BD, Xia Z, Cutruzzolá F, Allocatelli CT, Brunori M, La Mar GN. Solution (1)H NMR study of the influence of distal hydrogen bonding and N terminus acetylation on the active site electronic and molecular structure of Aplysia limacina cyanomet myoglobin. J Biol Chem 2000; 275:742-51. [PMID: 10625603 DOI: 10.1074/jbc.275.2.742] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The sea hare Aplysia limacina possesses a myoglobin in which a distal H-bond is provided by Arg E10 rather than the common His E7. Solution (1)H NMR studies of the cyanomet complexes of true wild-type (WT), recombinant wild-type (rWT), and the V(E7)H/R(E10)T and V(E7)H mutants of Aplysia Mb designed to mimic the mammalian Mb heme pocket reveal that the distal His in the mutants is rotated out of the heme pocket and is unable to provide a stabilizing H-bond to bound ligand and that WT and rWT differ both in the thermodynamics of heme orientational disorder and in heme contact shift pattern. The mean of the four heme methyl shifts is shown to serve as a sensitive indicator of variations in distal H-bonding among a set of mutant cyanomet globins. The heme pocket perturbations in rWT relative to WT were traced to the absence of the N-terminal acetyl group in rWT that participates in an H-bond to the EF corner in WT. Analysis of dipolar contacts between heme and axial His and between heme and the protein matrix reveal a small approximately 2 degrees rotation of the axial His in rWT relative to true WT and a approximately 3 degrees rotation of the heme in the double mutant relative to rWT Mb. It is demonstrated that both the direction and magnitude of the rotation of the axial His relative to the heme can be determined from the change in the pattern of the contact-dominated heme methyl shift and from the dipolar-dominated heme meso-H shift. However, only NOE data can determine whether it is the His or heme that actually rotates in the protein matrix.
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Affiliation(s)
- B D Nguyen
- Department of Chemistry, University of California, Davis, California 95616, USA
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142
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Hetman M, Xia Z. Signaling pathways mediating anti-apoptotic action of neurotrophins. Acta Neurobiol Exp (Wars) 2000; 60:531-45. [PMID: 11200182 DOI: 10.55782/ane-2000-1374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Neurotrophins promote survival and suppress apoptosis in many populations of neurons. Currently, phosphatidylinositol-3 kinase (PI-3K) is recognized as the main mediator of this protective effect. However, most of the data collected so far on the anti-apoptotic signaling of neurotrophins were obtained using trophic withdrawal paradigms. Recent data from our and other groups indicate that extracellular-signal-regulated kinase 1/2 (Erk 1/2) may play a critical role in suppressing neuronal apoptosis triggered by cellular damage. Thus, it appears that either Erk1/2 or PI-3K, depending on the nature of the death-inducing stimulus, can mediate anti-apoptotic signaling of neurotrophins. In this review, we discuss the contribution of Erk1/2 and PI-3K to neuroprotection by neurotrophins. We also present data suggesting possible mechanisms by which these pathways might suppress neuronal death.
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Affiliation(s)
- M Hetman
- Department of Environmental Health, University of Washington, Seattle, WA 98195-7234, USA.
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143
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Xia Z, Zhang W, Nguyen BD, Mar GN, Kloek AP, Goldberg DE. 1H NMR investigation of the distal hydrogen bonding network and ligand tilt in the cyanomet complex of oxygen-avid Ascaris suum hemoglobin. J Biol Chem 1999; 274:31819-26. [PMID: 10542205 DOI: 10.1074/jbc.274.45.31819] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The O(2)-avid hemoglobin from the parasitic nematode Ascaris suum exhibits one of the slowest known O(2) off rates. Solution (1)H NMR has been used to investigate the electronic and molecular structural properties of the active site for the cyano-met derivative of the recombinant first domain of this protein. Assignment of the heme, axial His, and majority of the residues in contact with the heme reveals a molecular structure that is the same as reported in the A. suum HbO(2) crystal structure (Yang, J., Kloek, A., Goldberg, D. E., and Mathews, F. S. (1995) Proc. Natl. Acad. Sci. U. S. A. 92, 4224-4228) with the exception that the heme in solution is rotated by 180 degrees about the alpha,gamma-meso axis relative to that in the crystal. The observed dipolar shifts, together with the crystal coordinates of HbO(2), provide the orientation of the magnetic axes in the molecular framework. The major magnetic axis, which correlates with the Fe-CN vector, is found oriented approximately 30 degrees away from the heme normal and indicates significant steric tilt because of interaction with Tyr(30)(B10). The three side chain labile protons for the distal residues Tyr(30)(B10) and Gln(64)(E7) were identified, and their relaxation, dipolar shifts, and nuclear Overhauser effects to adjacent residues used to place them in the distal pocket. It is shown that these two distal residues exhibit the same orientations ideal for H bonding to the ligand and to each other, as found in the A. suum HbO(2) crystal. It is concluded that the ligated cyanide participates in the same distal H bonding network as ligated O(2). The combination of the strong steric tilt of the bound cyanide and slow ring reorientation of the Tyr(30)(B10) side chain supports a crowded and constrained distal pocket.
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Affiliation(s)
- Z Xia
- Department of Chemistry, University of California, Davis, California 95616, USA
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144
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Xia Z, Bergstrand A, DePierre JW, Nässberger L. The antidepressants imipramine, clomipramine, and citalopram induce apoptosis in human acute myeloid leukemia HL-60 cells via caspase-3 activation. J Biochem Mol Toxicol 1999. [PMID: 10487422 DOI: 10.1002/(sici)1099-0461(1999)13:6%3c338::aid-jbt8%3e3.0.co;2-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Some widely used antidepressants such as imipramine, clomipramine, and citalopram have been found to possess antineoplastic effects. In the present study, these compounds were found to induce apoptotic cell death in human acute myeloid leukemia HL-60 cells. Apoptosis induced by the antidepressants was identified by electron microscopy and conventional agarose gel electrophoresis and was quantitated by propodium iodide staining and the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) via flow cytometry. Treatment with apoptosis-inducing concentrations of the antidepressants (80 microM imipramine, 35 microM clomipramine, or 220 microM citalopram) caused induction of caspase-3/caspase-3-like activity, which was monitored by the cleavage of poly(ADP-ribose) polymerase (PARP), the loss of the 32 kD caspase-3 (CPP32) precursor, and the cleavage of the fluorescent CPP32-like substrate PhiPhiLux. Pretreatment with a potent caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl-ketone (zVAD-fmk) inhibited antidepressant-induced CPP32/CPP32-like activity and apoptosis. Furthermore, activation of caspase induced by the antidepressants was preceded by the hypergeneration of intracellular reactive oxygen species (ROS). These results suggested that the antidepressants may induce apoptosis via a caspase-3-dependent pathway, and induction of apoptosis by the antidepressants may provide a clue for the mechanism of their antineoplastic effects.
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Affiliation(s)
- Z Xia
- Department of Biochemistry, Wallenberg Laboratory, Stockholm University, Sweden.
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145
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Hetman M, Kanning K, Cavanaugh JE, Xia Z. Neuroprotection by brain-derived neurotrophic factor is mediated by extracellular signal-regulated kinase and phosphatidylinositol 3-kinase. J Biol Chem 1999; 274:22569-80. [PMID: 10428835 DOI: 10.1074/jbc.274.32.22569] [Citation(s) in RCA: 459] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apoptosis is a form of programmed cell death that plays a pivotal role during development and in the homeostasis of the adult nervous systems. However, mechanisms that regulate neuronal apoptosis are not well defined. Here, we report that brain-derived neurotrophic factor (BDNF) protects cortical neurons against apoptosis induced by camptothecin or serum deprivation and activates the extracellular-signal-regulated kinase (ERK) and the phosphatidylinositol 3-kinase (PI 3-kinase) pathways. Using pharmacological agents and transient transfection with dominant interfering or constitutive active components of the ERK or the PI 3-kinase pathway, we demonstrate that the ERK pathway plays a major role in BDNF neuroprotection against camptothecin. Furthermore, ERK is activated in cortical neurons during camptothecin-induced apoptosis, and inhibition of ERK increases apoptosis. In contrast, the PI 3-kinase pathway is the dominant survival mechanism for serum-dependent survival under normal culture conditions and for BDNF protection against serum withdrawal. These results suggest that the ERK pathway is one of several neuroprotective mechanisms that are activated by stress to counteract death signals in central nervous system neurons. Furthermore, the relative contribution of the ERK and PI 3-kinase pathways to neuronal survival may depend on the type of cellular injury.
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Affiliation(s)
- M Hetman
- Toxicology Program, Department of Environmental Health, the Graduate Program in Neurobiology and Behavior, the Graduate Program in Molecular and Cell Biology, University of Washington, Seattle, Washington 98195-7234, USA
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Peterson HB, Xia Z, Wilcox LS, Tylor LR, Trussell J. Pregnancy after tubal sterilization with bipolar electrocoagulation. U.S. Collaborative Review of Sterilization Working Group. Obstet Gynecol 1999; 94:163-7. [PMID: 10432120 DOI: 10.1016/s0029-7844(99)00316-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To determine risk factors for pregnancy after tubal sterilization with bipolar electrocoagulation. METHODS A total of 2267 women who had bipolar electrocoagulation were followed for up to 8 to 14 years as part of a multicenter, prospective, cohort study conducted in medical centers in nine United States cities. We used proportional hazards analysis and cumulative life-table probabilities to assess pregnancy risk in these women. RESULTS The 5-year cumulative probability of pregnancy for women sterilized in 1978-1982 was 19.5 per 1000 procedures (95% confidence interval [CI], 12.2, 26.9); the comparable probability for women sterilized in 1985-1987 was significantly lower, 6.3 per 1000 procedures (95% CI, 0.0, 13.5) (one-tailed P = .01). Women enrolled in 1985-1987 who had fewer than three sites of coagulation had a probability of failure of 12.9 per 1000 procedures (95% CI, 0.0, 38.0); by contrast, women who had three or more sites coagulated had a probability of failure of 3.2 per 1000 procedures (95% CI, 0.0, 9.6) (one-tailed P = .01). CONCLUSION The long-term probability of pregnancy after tubal sterilization with bipolar coagulation was very low when three or more sites of the fallopian tube were coagulated. Bipolar coagulating systems can be highly effective for sterilization when the fallopian tube is coagulated adequately.
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Affiliation(s)
- H B Peterson
- Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia 30341-3724, USA
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147
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Xia Z, Wiebe LI, Miller GG, Knaus EE. Synthesis and biological evaluation of butanoate, retinoate, and bis(2,2,2-trichloroethyl)phosphate derivatives of 5-fluoro-2'-deoxyuridine and 2',5-difluoro-2'-deoxyuridine as potential dual action anticancer prodrugs. Arch Pharm (Weinheim) 1999; 332:286-94. [PMID: 10489539 DOI: 10.1002/(sici)1521-4184(19998)332:8<286::aid-ardp286>3.0.co;2-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A group of 3'-O-butanoyl, 5'-O-butanoyl, and 3',5'-di-O-butanoyl esters of 5-fluoro-2'-deoxyuridine (FDU), and 2',5-difluoro-2'-deoxyuridine (DFDU), 3'-O-retinoyl, and 3',5'-di-O-retinoyl esters of FDU, and 5'-O-bis(2,2,2-trichloroethyl)phosphoryl-FDU and its 3'-O-butanoyl ester, was synthesized. These compounds were designed to act as double prodrugs that would serve as a depot to release two active drugs that act through different mechanisms. Thus, a nucleotide derivative of FDU or DFDU could act as a competitive inhibitor for thymidylate synthase, whereas retinoic acid and butyric acid would be expected to induce cell differentiation. The in vitro anticancer activities for these prodrugs were determined against a panel of nine tumor types (leukemia, non-small cell lung, colon, CNS, melanoma, ovarian, renal, prostate, breast) that encompassed about 60 human tumor cell lines. Structure-activity relationships indicate that O-butanoyl esters of FDU are approximately equipotent to FDU, the O-butanoyl esters of DFDU are less active than FDU, and the retinoyl and bis(2,2,2-trichloroethyl)phosphate derivatives of FDU exhibit comparable activity to FDU. In addition to their cytotoxic effect, 3'-O-retinoyl-FDU (12) and 3'-O-butanoyl-5'-O-bis(2,2,2-trichloroethyl)phosphoryl-FD U (16) also induced in vitro cell differentiation of promyelocytic leukemia HL60 cells. These combined cytotoxic and cell differentiation effects exhibited by 12 and 16 produced greater morphological drug-induced granulation and neutrophil vacuolation, and more cell apoptosis, than observed upon exposure to either retinoic acid or sodium butanoate. Dose-escalation studies in mice showed that 12 or 16 did not induce any acute or chronic toxicity, change in plasma clinical chemistry parameters, or gross histapathological changes at 60 days following an initial dosage regimen of 0.013 mmol/kg i.p. for 7-consecutive days. The in vivo growth delay response of murine mammary EMT6 solid tumors suggests that 3'-O-retinoyl-FDU (12) delays tumor growth relative to the other prodrugs investigated, sodium butyrate, retinoic acid, FDU, or a combination of retinoic acid and FDU. These preliminary results suggest that 3'-O-retinoyl-FDU (12) warrants further in vivo investigation to determine its tissue biodistribution and pharmacokinetic parameters that would be of value in assessing its potential usefulness as an anticancer prodrug.
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Affiliation(s)
- Z Xia
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Canada
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148
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Xia Z, Roberts RO, Schottenfeld D, Lieber MM, Jacobsen SJ. Trends in prostatectomy for benign prostatic hyperplasia among black and white men in the United States: 1980 to 1994. Urology 1999; 53:1154-9. [PMID: 10367845 DOI: 10.1016/s0090-4295(98)00660-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES To estimate the annual rate of discharge for prostatectomy for benign prostatic hyperplasia (BPH) in black and white men from 1980 to 1994 using the National Hospital Discharge Survey. METHODS Overall and race-, age-, and year-specific utilization rates were estimated for the civilian population in the United States. Length of stay was calculated for each discharge, and the results were plotted over time. An expected number of discharges based on the rates observed in 1980 was estimated to determine the impact of decreased prostatectomy rates on the number of procedures that would have been expected in this aging population. RESULTS Discharge rates for whites were within a narrow range (233.2 to 274.5 per 100,000) from 1980 through 1990 and then displayed a monotonic decline after 1991 to 131.3 per 100,000 in 1994. Rates for blacks were 10% to 24% lower from 1980 to 1991; the decline in discharge rates began in 1993 for blacks, and by 1994 the racial gap had closed. Length of stay decreased throughout the period but length of stay averaged 30% longer for blacks throughout. On the basis of the observed rates of 1980, there were more than 140,000 fewer prostatectomies performed for BPH in 1994 than would have been expected owing to the aging of the population. CONCLUSIONS These data demonstrate that the black/white differences in prostatectomy for BPH that were observed in the 1980s have disappeared in recent years. Furthermore, rates have declined dramatically in all age- and race-specific groups. Further work is needed to determine whether this convergence in discharge rates is due to equalization of access to medical care or to differences in utilization of alternative therapies.
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Affiliation(s)
- Z Xia
- Department of Health Sciences Research, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA
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149
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Xia Z, Lundgren B, Bergstrand A, DePierre JW, Nässberger L. Changes in the generation of reactive oxygen species and in mitochondrial membrane potential during apoptosis induced by the antidepressants imipramine, clomipramine, and citalopram and the effects on these changes by Bcl-2 and Bcl-X(L). Biochem Pharmacol 1999; 57:1199-208. [PMID: 11230808 DOI: 10.1016/s0006-2952(99)00009-x] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
In order to investigate the molecular mechanism of the antineoplastic effects exerted by the antidepressive agents imipramine, clomipramine, and citalopram, we examined the effects of these compounds on cell viability, generation of reactive oxygen species (ROS), and mitochondrial membrane potential (DeltaPsi(m)) in human acute myeloid leukemia HL-60 cells. Our results indicate that exposure to these compounds causes a loss in cell viability by activating the apoptotic process, as identified by electron microscopy, DNA gel electrophoresis, and flow cytometry. The increased generation of ROS induced by these drugs was a relatively early event and preceded the loss of DeltaPsi(m). Overexpression of the antiapoptotic protein Bcl-2 or Bcl-X(L) prevents antidepressant-induced apoptosis, as well as loss of DeltaPsi(m), but does not affect the generation of ROS.
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Affiliation(s)
- Z Xia
- Unit for Biochemical Toxicology, Department of Biochemistry, Stockholm University, S-106 91, Stockholm, Sweden.
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150
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Beresford PJ, Xia Z, Greenberg AH, Lieberman J. Granzyme A loading induces rapid cytolysis and a novel form of DNA damage independently of caspase activation. Immunity 1999; 10:585-94. [PMID: 10367904 DOI: 10.1016/s1074-7613(00)80058-8] [Citation(s) in RCA: 166] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cytotoxic lymphocytes trigger apoptosis by releasing perforin and granzymes (Grn). GrnB activates the caspase apoptotic pathway, but little is known about GrnA-induced cell death. Perforin was used to load recombinant GrnA and GrnB and enzymatically inactive variants into target cells. GrnA induces single-strand DNA breaks that can be labeled with Klenow polymerase and visualized on alkaline gels. GrnA-induced DNA damage but not cytolysis requires GrnA proteolysis. GrnA-induced membrane perturbation, nuclear condensation, and DNA damage are unimpaired by caspase blockade. GrnA fails to induce cleavage of caspase-3, lamin B, rho-GTPase, or PARP. GrnA-induced cytotoxicity and cleavage of PHAP II, a previously identified GrnA substrate, are unimpaired in Jurkat cells that overexpress bcl-2. Therefore, GrnA activates a novel apoptotic pathway.
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Affiliation(s)
- P J Beresford
- Center for Blood Research and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA
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