1051
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Guo X, Lerner-Tung M, Chen HX, Chang CN, Zhu JL, Chang CP, Pizzorno G, Lin TS, Cheng YC. 5-Fluoro-2-pyrimidinone, a liver aldehyde oxidase-activated prodrug of 5-fluorouracil. Biochem Pharmacol 1995; 49:1111-6. [PMID: 7748192 DOI: 10.1016/0006-2952(95)98508-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
5-Fluorouracil (5-FU) is an effective antitumor agent used in treating various cancers. Because of its metabolism by intestinal and other cells, 5-FU has an inconsistent bioavailability that limits its oral use. 5-Fluoro-2-pyrimidione (5-FP), a 5-FU prodrug, was synthesized and found to be converted to 5-FU by aldehyde oxidase, an enzyme present in high concentrations in the livers of mice and humans but not in the gastrointestinal tract. Using BDF1 mice, the pharmacokinetics of 5-FP were studied and compared with those of 5-FU. The bioavailability of 5-FP given orally was 100% at a dosage of 25 mg/kg and 78% at a dosage of 50 mg/kg. The half-lives of both doses of 5-FP were at least 2-fold longer than the half-lives of the same doses of 5-FU, and the clearance rates of 5-FP were 3-fold slower. 5-FP was converted rapidly to 5-FU, in vivo. The resulting 5-FU was measured at a steady-state level of 40-70 microM in plasma, at a dosage of 25 mg/kg, that was sustained for at least 4 hr. Also, when given orally, 5-FP was shown to have potent activity against Colon 38 tumor cells and P388 leukemia cells in mice. The therapeutic index of 5-FP was similar to that of 5-FU in these mouse tumor models. The potential clinical use of 5-FP as a prodrug of 5-FU should be considered.
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1052
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Giergiel J, Pang AW, Hopster H, Guo X, Tong SY, Weller D. Surface structure of epitaxial Gd(0001) films on W(110) studied by quantitative LEED analysis. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:10201-10204. [PMID: 9977704 DOI: 10.1103/physrevb.51.10201] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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1053
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Guo X, Beerntsen BT, Zhao X, Christensen BM. Hemocyte alterations during melanotic encapsulation of Brugia malayi in the mosquito Armigeres subalbatus. J Parasitol 1995; 81:200-7. [PMID: 7535848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The involvement of hemocytes in melanotic encapsulation reactions against Brugia malayi was assessed in Armigeres subalbatus. Hemocyte populations, epitope changes, phenol oxidase (PO) activity, and the presence of an 84-kDa polypeptide were investigated in mosquitoes exposed to a B. malayi-infective bloodmeal (= immune-activated), in mosquitoes given a noninfective bloodmeal (= controls), in nonbloodfed mosquitoes (= naive), or in some combination of these. Total hemocyte populations in immune-activated mosquitoes significantly decreased at 24 hr postbloodmeal (PB) as compared with controls. At 48 and 72 hr PB, hemocyte population levels in immune-activated mosquitoes increased to control levels. Epitope changes, as indicated by wheat germ agglutinin (WGA) binding, also were observed. There was a significant increase in the percentage of hemocytes binding WGA in immune-activated mosquitoes at 24 hr PB as compared with controls. Furthermore, the activity of hemocyte PO, an enzyme involved in the melanotic encapsulation pathway, was significantly elevated at 12 hr PB in immune-activated mosquitoes as compared with controls. Analysis for the presence of an 84-kDa polypeptide in A. subalbatus indicates that a 2.0-kb message in total RNA hybridized to D6.12, an Aedes aegypti cDNA encoding an 84-kDa polypeptide that is associated with melanotic encapsulation responses. The hybridization of D6.12 to RNA was not greater in immune-activated as compared to control A. subalbatus, as has been observed in A. aegypti. Results indicate that these hemocyte changes correspond in time with the melanotic encapsulation reactions of A. subalbatus against filarial worms.
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1054
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Ogle CK, Guo X, Wu JZ, Ogle JD, Fischer JE. Effect of hepatocytes from normal or endotoxin treated animals on the production of tumour necrosis factor, interleukin-6, and prostaglandin-E2 by macrophages incubated in vitro with various fatty acids. THE EUROPEAN JOURNAL OF SURGERY = ACTA CHIRURGICA 1995; 161:123-127. [PMID: 7772629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
OBJECTIVE To find out if the in vitro production of tumour necrosis factor (TNF), interleukin 6 (IL-6) and prostaglandin E2 (PGE2) by macrophages (P3888D1) were influenced by the addition to the culture media of hepatocytes from normal guinea pigs and from guinea pigs after infusion with endotoxin with and without fatty acids. DESIGN Laboratory experiment. SETTING University hospital, United States MATERIAL 12 male Hartley guinea pigs. MAIN OUTCOME MEASURES Concentrations of TNF-alpha, IL-6, and PGE2. RESULTS Hepatocytes inhibited the production of TNF by macrophages. Those from animals pretreated with endotoxin caused a large increase in the production of PGE2 and affected the production of IL-6 only in the presence of fatty acids. Fatty acids differed from each other in their effects on production of TNF-alpha and PGE2, but had no effect on the production of IL-6. CONCLUSION These results support the concept that hepatocytes and macrophages may interact in vivo, and this interaction may be influenced both by fatty acids that arise from lipid metabolism and from endotoxin present during sepsis and translocation.
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1055
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Guo X, Zhang YP, Mitchell DA, Denhardt DT, Chambers AF. Identification of a ras-activated enhancer in the mouse osteopontin promoter and its interaction with a putative ETS-related transcription factor whose activity correlates with the metastatic potential of the cell. Mol Cell Biol 1995; 15:476-87. [PMID: 7799957 PMCID: PMC231995 DOI: 10.1128/mcb.15.1.476] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The role of RAS in transducing signals from an activated receptor into altered gene expression is becoming clear, though some links in the chain are still missing. Cells possessing activated RAS express higher levels of osteopontin (OPN), an alpha v beta 3 integrin-binding secreted phosphoprotein implicated in a number of developmental, physiological, and pathological processes. We report that in T24 H-ras-transformed NIH 3T3 cells enhanced transcription contributes to the increased expression of OPN. Transient transfection studies, DNA-protein binding assays, and methylation protection experiments have identified a novel ras-activated enhancer, distinct from known ras response elements, that appears responsible for part of the increase in OPN transcription in cells with an activated RAS. In electrophoretic mobility shift assays, the protein-binding motif GGAGGCAGG was found to be essential for the formation of several complexes, one of which (complex A) was generated at elevated levels by cell lines that are metastatic. Southwestern blotting and UV light cross-linking studies indicated the presence of several proteins able to interact with this sequence. The proteins that form these complexes have molecular masses estimated at approximately 16, 28, 32, 45, 80, and 100 kDa. Because the approximately 16-kDa protein was responsible for complex A formation, we have designated it MATF for metastasis-associated transcription factor. The GGANNNAGG motif is also found in some other promoters, suggesting that they may be similarly controlled by MATF.
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1056
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Korczak JF, Pugh EW, Premkumar S, Guo X, Elston RC, Bailey-Wilson JE. Effects of marker information on sib-pair linkage analysis of a rare disease. Genet Epidemiol 1995; 12:625-30. [PMID: 8787984 DOI: 10.1002/gepi.1370120617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Model-free sib-pair linkage analysis was used to screen the GAW9-Problem 1 data set for evidence of linkage of a rare disease to any of 360 highly polymorphic marker loci. Negative regressions nominally significant at the alpha = 0.05 level were obtained for 44 markers; however all of these proved to be Type I errors. None of the four disease loci were detected by sib-pair linkage, which was not surprising, given the particular model and sampling scheme used to generate these data. Neither deleting parental marker genotypic information nor misspecifying marker allele frequency estimates substantially increased the Type I error rate. A two-stage testing procedure using a 10 or 20 cM map and a liberal first stage significance level gave the same overall results as a one-stage 2 cM map but required only about 42% or 22% as many markers, respectively.
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1057
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Guo X, Allen SK. Reproductive Potential and Genetics of Triploid Pacific Oysters, Crassostrea gigas (Thunberg). THE BIOLOGICAL BULLETIN 1994; 187:309-318. [PMID: 29281392 DOI: 10.2307/1542288] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The reproductive potential and genetics of triploidy were studied in the Pacific oyster. DNA content in sperm from triploids showed a single peak at 1.5c as determined by flow cytometry. In eggs from triploids, trivalents were the dominant form of synapsed chromosomes, although the degree of synapsis varied considerably within and among females. Some eggs went through complete synapsis and formed 10 trivalents, chromosomes; most had a mixture of 11-13 trivalents, bivalents, and univalents. Factorial matings were produced from diploid (D) and triploid (T) parent oysters, creating four crosses: DD, DT, TD, and TT (female first). Gametes from triploids were fully capable of fertilization. After fertilization, eggs from triploids went through two meioses and released two polar bodies as diploid eggs did. Karyological analyses showed that average ploidy of the resultant embryos was 2.0 n for DD, 2.46 n for DT, 2.52 n for TD, and 2.88 n for TT. Survival of fertilized eggs to metamorphosis and settlement was about 21% for DD, but considerably lower on other crosses: 0.0007% for DT, 0.0463% for TD, and 0.0085% for TT. Nine months after matings, all survivors from DT crosses were diploid. Survivors from TD crosses consisted of 33% diploids, 57% triploids, and 10% tetraploids. Survivors from the TT crosses consisted of 90% triploids, 4% diploids, and 6% mosaics. We hypothesize that differences in ploidy composition between DT and TD embryos and survivors were caused by pro-egg segregations that favor the retention, rather than loss, of extra chromosomes in the egg. The reproductive potential of triploids and evolutionary implications are discussed.
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1058
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Guo X, Allen SK. Sex determination and polyploid gigantism in the dwarf surfclam (Mulinia lateralis Say). Genetics 1994; 138:1199-206. [PMID: 7896101 PMCID: PMC1206258 DOI: 10.1093/genetics/138.4.1199] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Mulinia lateralis, the dwarf surfclam, is a suitable model for bivalve genetics because it is hardy and has a short generation time. In this study, gynogenetic and triploid M. lateralis were successfully induced. For gynogenesis, eggs were fertilized with sperm irradiated with ultraviolet light and subsequently treated with cytochalasin B to block the release of the second polar body (PB2). Triploidy was induced by blocking PB2 in normally fertilized eggs. The survival of gynogenetic diploids was very low, only 0.7% to 8 days post-fertilization (PF), compared with 15.2% in the triploid groups and 27.5% in the normal diploid control. Larvae in all groups metamorphosed at 8-10 days PF, and there was no significant post-larval mortality. At sexual maturation (2-3 months PF), all gynogenetic diploids were female, and there was no significant difference (P > 0.05) in sex ratio between diploids and triploids. These results suggested that the dwarf surfclam may have an XX-female, XY-male sex determination with Y-domination. Compared with diploids, triploids had a relative fecundity of 59% for females and 80% for males. Eggs produced by triploid females were 53% larger (P < 0.001) in volume than those from diploid females. In both length and weight measurements at three months PF, the gynogenetic diploids were not significantly (P > 0.33) different from normal diploid females, suggesting that inbreeding depression was minimal in meiosis II gynogens. Triploid clams were significantly larger (P < 0.001) than normal diploids. We hypothesize that the increased body-size in triploids was caused by a polyploid gigantism due to the increased cell volume and a lack of cell-number compensation.
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1059
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Zhang SY, Caamano J, Cooper F, Guo X, Klein-Szanto AJ. Immunohistochemistry of cyclin D1 in human breast cancer. Am J Clin Pathol 1994; 102:695-8. [PMID: 7942638 DOI: 10.1093/ajcp/102.5.695] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Cyclin D1/PRAD 1, a cell cycle-related gene mapped to chromosome 11q13, has been found to be amplified in some breast cancers and squamous cell carcinomas of the head and neck, and esophagus. In this study, overexpression of cyclin D1/PRAD1 gene was demonstrated immunohistochemically in 35 of 43 (81.3%) cases of human breast cancer, with a newly available anticyclin D antibody. Neither normal epithelial components nor glandular structures from samples of fibrocystic disease, were reactive. Amplification of the gene was detected in 4 of 23 (17%) cases by Southern analysis. Increased gene dosage does not seem to be the only mechanism that resulted in increased protein expression as detected by immunohistochemistry. Because the less differentiated high grade tumors exhibited a more intense nuclear stain and non-neoplastic epithelial components were not stained, the use of cyclin D1/PRAD1 has potential as a tumor marker.
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1060
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Ge K, Weisell R, Guo X, Cheng L, Ma H, Zhai F, Popkin BM. The body mass index of Chinese adults in the 1980s. Eur J Clin Nutr 1994; 48 Suppl 3:S148-54. [PMID: 7843152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Patterns and trends in the body composition of Chinese adults are studied with data from the 1982 China Nationwide Nutrition Survey (CNS-82) and the 1989 China Health and Nutrition Survey (CHNS-89). The CNS-82 showed rural inhabitants were approximately 3 kg lighter than urban residents and approximately 2.2 cm shorter. Males were heavier (55.2 +/- 7.4 vs 50.7 +/- 8.0 kg) and taller (165.3 +/- 7.3 and 153.5 +/- 6.3 cm). Using a cut-off for underweight of a body mass index (BMI: kg/m2) < 18.5 and for obesity of > 25, 11.6% and 12.9% of the urban and rural sample were underweight and 9.8% and 6.9% respectively were overweight. The CHNS-89 surveyed 5138 adults aged 20-45 in eight selected provinces. The proportion of underweight in both urban and rural samples declined slightly (approximately 1.3%) but the proportion of obesity increased considerably (4.8% for the urban sample and 2% for the rural one). Increased income was significantly associated with reduced low body mass index (BMI: kg/m2) in the urban sample while, for the rural and overall samples, the opposite was found for obesity. Provincial patterns in energy intake were not associated with the distribution of BMI while occupation was. In particular, government officials and housewives were much more likely to be obese as also were subpopulation groups consuming greater proportions of energy from animal sources. Over 80% of the population fell in the normal BMI range (18.5-25). This may relate to the relatively even distribution of food in China during the past several decades.
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1061
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Yang Y, Wang X, Guo X. [Effects of high iodine and high fluorine on children's intelligence and the metabolism of iodine and fluorine]. ZHONGHUA LIU XING BING XUE ZA ZHI = ZHONGHUA LIUXINGBINGXUE ZAZHI 1994; 15:296-8. [PMID: 7859263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
An investigation on children's intelligence and the metabolism of iodine and fluorine in high iodine and fluorine regions was carried out. The results were as follows. In high iodine and high fluorine areas, the thyroid enlargement prevalence rate among inhabitants and that among children were 3.8% and 29.8%, respectively. The dental fluorosis prevalence rate among inhabitants and that among children was 35.48% and 72.9%, respectively. The pupils' average intelligence quotient (IQ) was 76.67 +/- 7.75, slightly lower than the control point, but that of low intelligent pupils was 16.7%. The urinary iodine and urinary fluoride were 816.25 +/- 1.80 micrograms/L and 2.08 +/- 1.03 mg/L, respectively, markedly higher than the control point. The thyroid iodine-131 (131I) uptake rate was markedly lower than the control point. The values at 3 h and 24 h were 9.36 +/- 1.55% and 9.26 +/- 4.63%, respectively. The serum TSH was obviously higher than the control point. These results indicate that high iodine and high fluorine exert severe damage to human body.
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1062
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Krudy GA, Kleerekoper Q, Guo X, Howarth JW, Solaro RJ, Rosevear PR. NMR studies delineating spatial relationships within the cardiac troponin I-troponin C complex. J Biol Chem 1994; 269:23731-5. [PMID: 8089144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
NMR spectroscopy and selective isotope labeling of both recombinant cardiac troponin C (cTnC3) and a truncated cardiac troponin I (cTnI/NH2) lacking the N-terminal 32-amino acid cardiac-specific sequence have been used to probe protein-protein interactions central to muscle contraction. Using [methyl-13C]Met-labeled cTnC3, all 10 cTnC Met residues of Ca(2+)-saturated cTnC3 could be resolved in the two-dimensional heteronuclear single- and multiple-quantum coherence spectrum of the cTnI.cTnC complex. Based on the known Met assignments in cTnC3, the largest chemical shift changes were observed for Met81, Met120, Met137, and Met157. Methionines 120, 137, and 157 are all located in the C-terminal domain of cTnC. Methionine 81 is located at the N terminus of the central helix. Minimal chemical shift changes were observed for Met45, Met47, and Met103 of cTnC3 in the cTnI.cTnC complex. All 6 Met residues in [methyl13C]Met-labeled cTnI/NH2 could be resolved in the cTnI.cTnC complex, suggesting that both cTnI and cTnC form a stable homogeneous binary complex under the conditions of the NMR experiment. In the absence of added protease inhibitors in the cTnI.cTnC complex, cTnI/NH2 was found to undergo selective proteolysis to yield a 5.5-kDa N-terminal fragment corresponding to residues 33-80. Judging from the NMR spectra of [methyl13C]Met-labeled cTnC3, cTnI-(33-80) was sufficient for interaction with the C-terminal domain of cTnC in a manner identical to that observed for native cTnI/NH2. However, in the presence of the proteolytic fragment cTnI-(33-80), the chemical shift of Met81 was not perturbed from its position in free cTnC3. Thus, residues located C-terminal to Arg80 in cTnI appear to be responsible for interaction with the N-terminal half of cTnC. Taken together, these results provide strong evidence for an antiparallel arrangement for the two proteins in the troponin complex such that the N-terminal portion of cTnI interacts with the C-terminal domain of cTnC. This interaction likely plays a role in maintaining the stability of the TnI.TnC complex.
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Waddill GD, Tobin JG, Guo X, Tong SY. Spin-polarized photoelectron diffraction using circularly polarized x rays. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:6774-6778. [PMID: 9974630 DOI: 10.1103/physrevb.50.6774] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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1064
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Guo X, Zhao Y. Treating subluxation of sacroiliac joint by manipulation--a report of 100 cases. J TRADIT CHIN MED 1994; 14:192-4. [PMID: 7799653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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1065
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Guo X, Spencer JW, Suess PE, Hickey JE, Better WE, Herning RI. Cognitive brain potential alterations in boys exposed to opiates: in utero and lifestyle comparisons. Addict Behav 1994; 19:429-41. [PMID: 7992677 DOI: 10.1016/0306-4603(94)90065-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Several studies have observed that intrauterine exposure to opiates results in emotional and cognitive complications for the child, but genetic and postnatal social-environmental factors may also affect the CNS development of these children. To assess the relative contribution of the in utero and social-environmental (lifestyle) effects of opiate exposure, event-related potentials (ERPs) and performance were studied in three groups of 7- to 12-year-old boys: (1) the in utero/lifestyle group (IU/LS) contained 16 boys who were exposed to opiates (in utero and lived with opiate-abusing mothers, (2) the lifestyle group (LS) included 14 boys who lived with opiate-abusing mothers, and (3) the control group (CON) composed of 13 boys. The cognitive ERP components and task performance were recorded in the Auditory Rare Event Monitoring (AREM) task and the Sternberg Memory task (Sternberg, 1975). On the AREM and Sternberg Memory tasks, P200 component was significantly decreased for the IU/LS and LS groups. On the Sternberg Memory task, percent correct was also significantly impaired in IU/LS and LS groups. The ERP alterations in the boys living with opiate-abusing mothers with and without intrauterine opiate exposure were similar. A dysfunctional social environment may contribute to the cognitive deficits seen in the sons of opiate-abusing mothers.
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1066
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Guo X, Wattanapermpool J, Palmiter KA, Murphy AM, Solaro RJ. Mutagenesis of cardiac troponin I. Role of the unique NH2-terminal peptide in myofilament activation. J Biol Chem 1994; 269:15210-6. [PMID: 8195157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Phosphorylation of Ser residues in the NH2-terminal extension unique to cardiac troponin I (cTnI) is known to occur through protein kinase A and to alter myofilament Ca2+ activation (Robertson, S. P., Johnson, J. D., Holroyde, M. J., Kranias, E. G., Potter, J. D., and Solaro, R. J. (1982) J. Biol. Chem. 257, 260-263). Yet, how the NH2-terminal extension may itself affect thin filament Ca2+ signaling is unknown. To approach this question we have used molecular cloning, mutagenesis, and bacterial synthesis of a full-length cTnI and a truncated mutant (cTnI/NH2) missing the 32 amino acids. Using reconstituted preparations we could show no differences between cTnI and cTnI/NH2 either in inhibition of actomyosin ATPase activity, in Ca(2+)-reversible inhibitory activity, or in the relation between pCa and Ca2+ binding to the regulatory site of cTnC at either pH 7.0 or 6.5. There were also no significant differences at either pH in the pCa-MgATPase activity relation of myofibrils into which the various species of TnI has been exchanged. Our results indicate: 1) that phosphorylation most likely induces a new state of TnI activity rather than altering an intrinsic effect of the NH2-terminal peptide on Ca2+ activation; and 2) that domains outside the NH2-terminal extension are important with regard to differences in effects of acidic pH on Ca2+ activation on cardiac and skeletal myofilaments.
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Ling Q, Guo ZG, Su Z, Guo X. Regression of cardiac hypertrophy and myosin isoenzyme patterns by losartan and captopril in renovascular hypertensive rats. ZHONGGUO YAO LI XUE BAO = ACTA PHARMACOLOGICA SINICA 1994; 15:206-210. [PMID: 7976371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
To test the effect of losartan and captopril on cardiac hypertrophy and myosin isoenzyme, two-kidney, one-clip (2K 1C) renovascular hypertensive rats (RHR) were used. Eight weeks after the onset of hypertension, losartan 5 mg.kg-1.d-1 and captopril 50 mg.kg-1.d-1 were administered p.o. to 2 groups of RHR, respectively for 8 wk. The results showed that captopril significantly decreased the cardiac mass (607 +/- 169 mg vs 1029 +/- 132 mg) and total protein content (120 +/- 38 mg vs 198 +/- 31 mg), concomitant with significant decrease of arterial blood pressure (BP) (15.4 +/- 5.2 kPa vs 28.5 +/- 4.9 kPa). Losartan also induced a significant decrease in cardiac mass (671 +/- 116 mg vs 1029 +/- 132 mg) and protein content (142 +/- 29 mg vs 198 +/- 31 mg), as well as significantly lowered the BP (15.2 +/- 2.1 kPa vs 28.5 +/- 4.9 kPa). It is important to be note that both drugs normalized the shift of myosin isoenzyme in RHR. These results indicated that both drugs, having potent antihypertensive effects, can effectively reverse the cardiac hypertrophy and abnormal distribution of myosin isoenzyme patterns.
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1068
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Guo X, Wattanapermpool J, Palmiter K, Murphy A, Solaro R. Mutagenesis of cardiac troponin I. Role of the unique NH2-terminal peptide in myofilament activation. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36593-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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1069
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Ogle CK, Guo X, Szczur K, Hartmann S, Ogle JD. Production of tumor necrosis factor, interleukin-6 and prostaglandin E2 by LPS-stimulated rat bone marrow macrophages after thermal injury: effect of indomethacin. Inflammation 1994; 18:175-85. [PMID: 8070901 DOI: 10.1007/bf01534558] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The effect of thermal injury on the in vitro production of TNF, IL-6, and PGE2 by bone marrow-derived, LPS-stimulated rat macrophages was studied. Thermal injury caused a general hyperactivity in the production of the mediators by the cells. Indomethacin, a cyclooxygenase inhibitor of PGE2 synthesis, inhibited the production of IL-6 and PGE2 but had no effect on the production of TNF. These results suggest that the observed low concentration of PGE2 produced by the cells was insufficient to cause inhibition of TNF synthesis; thus, the effect of indomethacin would be undetectable. The results also suggest that indomethacin may act directly in inhibiting the production of IL-6 by the macrophages. The hyperactive effect of thermal injury on the production of inflammatory mediators by newly differentiated bone marrow derived macrophages can be important in the overall systemic response to the insult.
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1070
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Guo X, Wakade AR. Differential secretion of catecholamines in response to peptidergic and cholinergic transmitters in rat adrenals. J Physiol 1994; 475:539-45. [PMID: 8006835 PMCID: PMC1160404 DOI: 10.1113/jphysiol.1994.sp020092] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
1. Rat adrenal medulla is stimulated by cholinergic and peptidergic transmitters released from splanchnic nerves. The peptidergic transmitter has been identified as vasoactive intestinal polypeptide (VIP) and its contribution in comparison to that of acetylcholine (ACh) is more prominent at low neuronal activity. The purpose of this study is to determine if ACh and VIP cause differential secretion of adrenaline and noradrenaline and whether the differential secretion also occurs when splanchnic nerves are stimulated at different frequencies. 2. Perfusion of the left adrenal gland with Krebs solution for several hours did not change adrenaline and noradrenaline contents (15.2 micrograms and 3.5 micrograms, respectively) and their ratio (4.4) from those of the unperfused right adrenal medulla (15.2 micrograms, 3.3 micrograms and 4.8, respectively). 3. Perfusion with ACh (10 microM for 4 min) resulted in the secretion of 109 ng of catecholamines and the ratio of adrenaline to noradrenaline was 3.8. Although the secretion increased with increased concentrations of ACh (30 and 100 microM), the ratios remained between 3 and 4. 4. Perfusion with VIP (10 microM for 4 min) resulted in the secretion of 27 ng of catecholamines and the ratio of adrenaline to noradrenaline was 9.7. A higher concentration of VIP (20 microM for 4 min) resulted in the secretion of greater amounts of catecholamines (102 ng) without significantly altering the ratio of adrenaline to noradrenaline (10.9). 5. Perfusion with as low as 0.01 microM pituitary adenylate cyclase-activating polypeptide (PACAP) increased the secretion of catecholamines to 31 ng and the secretion increased in a dose-dependent manner up to 0.3 microM.(ABSTRACT TRUNCATED AT 250 WORDS)
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Chowdhury PS, Guo X, Wakade TD, Przywara DA, Wakade AR. Exocytosis from a single rat chromaffin cell by cholinergic and peptidergic neurotransmitters. Neuroscience 1994; 59:1-5. [PMID: 7910672 DOI: 10.1016/0306-4522(94)90092-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Secretion of catecholamines from chromaffin cells is mediated by cholinergic and peptidergic neurotransmitters. The cholinergic transmitter acetylcholine activates both nicotinic and muscarinic receptors to trigger catecholamine secretion in rat adrenal medulla. Vasoactive intestinal polypeptide (VIP) has been identified as the peptidergic transmitter in rat adrenal medulla and may also be the non-cholinergic transmitter in bovine adrenal. Pituitary adenylate cyclase activating polypeptide (PACAP), a VIP-like secretin peptide, is also found in the adrenal, and is a potent secretagogue. Thus, PACAP may be another peptidergic transmitter at the adrenal synapse. A most intriguing property of rat chromaffin cells is that stimulation of nicotinic, muscarinic, VIP or PACAP receptors are each able to produce robust catecholamine secretion on their own. This raises the question of whether a single chromaffin cell can respond to each of the above agonists or whether the secretion is due to subpopulations of chromaffin cells. This issue was addressed by using electrochemical techniques to monitor exocytosis from individual chromaffin cells in culture. We demonstrate that acetylcholine, nicotine, muscarine, VIP and PACAP are each able to evoke catecholamine secretion from a single chromaffin cell. Some cells only responded to acetylcholine. Furthermore, each agonist produced a distinct pattern of exocytosis. Muscarine-evoked secretion exhibited a latency of 0.5-2 s, but exocytosis persisted up to 30 s following 500 ms stimulation. Nicotine produced an immediate response which usually ended within 10 s. The secretory pattern following acetylcholine appeared to be the sum of the nicotinic and muscarinic patterns, showing both rapid onset and longer duration.(ABSTRACT TRUNCATED AT 250 WORDS)
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Zhang YL, Guo X, Cheng YC, Lee KH. Antitumor agents. 148. Synthesis and biological evaluation of novel 4 beta-amino derivatives of etoposide with better pharmacological profiles. J Med Chem 1994; 37:446-52. [PMID: 8120864 DOI: 10.1021/jm00030a003] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A series of novel 4 beta-amino derivatives of etoposide (1), which can form water-soluble salts and demonstrate excellent activity against mdr- and topo II-resistant cell lines, have been synthesized. Compared with etoposide, compounds 5-6, 8, and 10-16 show comparable or greater inhibition of human DNA topo II. In a cellular protein-DNA complex formation assay, compounds 5-6, 8, 10-14, and 16 are more potent than 1. A dose-response study of 8 shows that it is 20 times more active in formation of protein-linked DNA breaks than etoposide. Furthermore, both 8 and its free base 7 were found to be highly active toward etoposide-resistant KB cell lines. All compounds were also evaluated in vitro against a total of 56 human tumor cell lines derived from seven cancer types. Comparison of the log10 GI50 mean graph midpoints of 5-19 (-4.89 to -7.30) with that of 1 (-4.08) shows these new analogs to be 6-1659-fold more active than 1.
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Palmer MJ, Bantle JA, Guo X, Fargo WS. Genome size and organization in the ixodid tick Amblyomma americanum (L.). INSECT MOLECULAR BIOLOGY 1994; 3:57-62. [PMID: 8069417 DOI: 10.1111/j.1365-2583.1994.tb00151.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We used DNA reassociation kinetics to determine genome size and organization in the ixodid tick Amblyomma americanum. We calculated the genome size of A. americanum to be approximately 1.08 pg or 1.04 x 10(9) base pairs and to consist of 35.8% unique DNA, 4.2% foldback sequences, 17.9% highly repetitive sequences, and 42.1% moderately repetitive sequences. Comparison of the reassociation kinetics of long and short fragments revealed repetitive sequences to be distributed in a pattern of long period interspersion, a feature that, to date, has been associated with arthropod genomes that lack a high percentage of repetitive DNA.
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Gong YH, Guo X, Zhang XQ. [Immunoelectron microscopic studies on the process of tumor cytolysis mediated by lymphokine activated NK cells]. ZHONGHUA BING LI XUE ZA ZHI = CHINESE JOURNAL OF PATHOLOGY 1994; 23:17-9. [PMID: 8044855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The second fraction (F2) cells isolated from PBL by discontinuous Percoll density gradient centrifugation were used as the enriched natural killer (NK) cells. After being incubated with rIL2, the activated F2 cells (F2 LAK) acquired the cytolytic ability upon NK resistant tumor cell lines. In F2 LAK, about 45% of the cells were CD16+, therefore F2 LAK were used as the enriched CD16+LAK cells (or lymphokine activated NK cells). The cytolysis process of lung adenocarcinoma LTEPa-2 or K562 tumor cells mediated by CD16+LAK cells were investigated with colloidal gold labelled Ab via scanning and transmission immunoelectron microscopy. The results showed that the CD16+LAK cells extended their protrusions deep into the target cells. Crypts of various diameter and depth were observed on the surface of the target cells with membrane injury at the bottom of the crypts. It was found that the cytoplasmic granules and vacuoles of CD16+LAK cells were concentrated in the area close to the E-T conjugated side, and sometimes the granules were found within the LAK protrusions. The attacked target cells died by apoptosis and necrosis. This study provided direct evidence that lymphokine activated NK cells are effectors of LAK cells.
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Zhou XM, Lee KJ, Cheng J, Wu SS, Chen HX, Guo X, Cheng YC, Lee KH. Antitumor agents. 144. New gamma-lactone ring-modified arylamino etoposide analogs as inhibitors of human DNA topoisomerase II. J Med Chem 1994; 37:287-92. [PMID: 8295216 DOI: 10.1021/jm00028a012] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The trans-fused gamma-lactone ring of etoposide is readily epimerized to its cis epimer, which is biologically inactive, or is metabolized to the inactive ring-opened hydroxy acids. Modification of this gamma-lactone ring of 4 beta-(arylamino)-4'-O-demethyl-4-desoxypodophyllotoxin resulted in several compounds (15-16, 21-22, and 24) that should block this epimerization and the resulting biological deactivation. In a topoisomerase II inhibition assay, compounds 21, 22, and 24 showed comparable activity to etoposide. In a protein-linked DNA complex formation assay, compounds 21 and 22 were more active than etoposide.
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