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Lu K, Lee TC, Chen HJ. Closed reduction of bilateral locked facets of the cervical spine under general anaesthesia. Acta Neurochir (Wien) 1998; 140:1055-61. [PMID: 9856249 DOI: 10.1007/s007010050214] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Bilateral facet interlocking of the cervical spine is a relatively uncommon type of cervical spinal injury. It is frequently associated with devastating neurological symptoms and signs. Early reduction of the locked facets is thought to be critical in preventing progressive secondary spinal cord injury. Whereas skull tong traction remains our primary option for closed reduction of bilateral locked facets of the cervical spine, it is not always successful, even with heavy traction weights. Other more aggressive measures may occasionally be required. The authors report their experience in reducing bilateral locked facets of the cervical spine by manual closed reduction. METHODS This small series consists of six cases of cervical spinal injury with bilateral locked facets in which manual closed reduction under general anaethesia and muscle relaxation was used. Three of them presented with complete quadriplegia (Frankel class A). One case presented with incomplete but severe neurological deficits (Frankel class B). After unsuccessful closed reduction with skull traction, these patients were treated by manual closed reduction under general anaesthesia and muscle relaxation, followed by anterior discectomy, interbody fusion and stabilization. RESULTS All cases made neurological improvement after the procedures. Even in cases with initial severe neurological deficits, the recovery was remarkable. The recovery was dramatic in two cases. Case 1 improved from Frankel class B to E; and Case 5 from Frankel class A to D. No case deteriorated neurologically after the procedures. Pneumonia occurred in Case 3; and stress ulcer accompanied by haemorrhage was noted in Case 4. None of these complications was directly related to the procedures. CONCLUSION The potential for improvement of neurological function following early and successful reduction and fixation of the dislocated spine is emphasized. With meticulous techniques, manual closed reduction may be an effective alternative to skull tong traction when the latter fails.
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Chen HJ, Zhang L, Cox J, Cunningham JA, Chung FL. DNA adducts of 2,3-epoxy-4-hydroxynonanal: detection of 7-(1', 2'-dihydroxyheptyl)-3H-imidazo[2,1-i]purine and 1,N6-ethenoadenine by gas chromatography/negative ion chemical ionization/mass spectrometry. Chem Res Toxicol 1998; 11:1474-80. [PMID: 9860490 DOI: 10.1021/tx980107o] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
2,3-Epoxy-4-hydroxynonanal (EH) is a bifunctional aldehyde formed by epoxidation of trans-4-hydroxy-2-nonenal, a peroxidation product of omega-6 polyunsaturated fatty acids. EH is mutagenic and tumorigenic and capable of modifying DNA bases forming etheno adducts in vitro. Recent studies showed that etheno adducts are present in tissue DNA of humans and untreated rodents, suggesting a potential endogenous role of EH in their formation. A sensitive assay is needed so we can determine whether EH is involved in etheno adduct formation in vivo and study the biological significance of the etheno adducts in DNA. In this study, we developed a gas chromatography/negative ion chemical ionization/mass spectrometry assay for the analysis of 1, N6-ethenoadenine (epsilonAde) and 7-(1', 2'-dihydroxyheptyl)-3H-imidazo[2,1-i]purine (DHH-epsilonAde) in DNA; both are products from the reaction of adenine with EH. The assay entails the following sequence of steps: (1) addition of [15N5]epsilonAde and [15N5]DHH-epsilonAde to DNA as internal standards, (2) acid hydrolysis of DNA, (3) adduct enrichment by C18 solid phase extraction (SPE), (4) derivatization by pentafluorobenzylation (PFB), (5) separation of PFB-epsilonAde and PFB-DHH-epsilonAde on a Si SPE column, (6) acetonide (ACT) formation of PFB-DHH-epsilonAde, and (7) GC/MS analysis with selective ion monitoring (SIM). The limit of detection by on-column injection for PFB-epsilonAde monitoring of the (M - PFB)- ion at m/z 158 was 30 amol and for ACT-PFB-DHH-epsilonAde monitoring of the (M - PFB)- ion at m/z 328 was 0.4 fmol; the detection limits for the entire assay were 6.3 fmol for epsilonAde and 36 fmol for DHH-epsilonAde. In calf thymus DNA modified with EH at 37 degreesC for 50 h, both epsilonAde and DHH-epsilonAde were detected at high levels by this method, 4.5 +/- 0.7 and 90.8 +/- 8.7 adducts/10(3) adenine, respectively. These levels were also verified by HPLC fluorescence analysis, indicating that EH extensively reacts with adenine in DNA, forming etheno adducts. The high sensitivity of the assay suggests that it may be used in the analysis of ethenoadenine adducts in vivo.
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Chen HJ, Teng HC, Li SS. Molecular characterization of germline mutations in neurofibromatosis 2 in two families. J Formos Med Assoc 1998; 97:869-72. [PMID: 9884492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
Neurofibromatosis 2 (NF2) is an autosomal dominant disorder that predisposes patients to central nervous system tumors. It is caused by mutations in the NF2 tumor suppressor gene, which is located on chromosome 22q12. We studied 2 multigenerational NF2 families (three members of family 1 and the proband of the family) by gene mutation analysis and clinical assessment. One member of family 1 had a 169 C-->T point mutation at codon 57 of exon 2 and had a severe phenotype. His father had a silent 1113 C-->T point mutation at codon 371 of exon 11 and had a normal phenotype. The proband of family 2 had a deletion at nucleotide 720 G (codon 240) of exon 8. This led to a frameshift and termination at codon 250, and a severe NF2 phenotype. Our results indicate that clinical abnormalities can be present in carriers. Nonsense and frameshift mutations in the NF2 tumor suppressor gene are associated with phenotypes. The clinical abnormalities can develop at a young age.
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Chen HJ, Teng RJ, Tsou Yau KI, Yang CM. Optimal timing of retina examinations for premature infants. J Formos Med Assoc 1998; 97:552-6. [PMID: 9747066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Developments in modern neonatal intensive care have resulted in increased survival of very premature infants. Along with this increase in survival, there has been a concomitant increase in the frequency of retinopathy of prematurity (ROP). We investigated the relationship between the severity and the time course of ROP as well as the optimal time for retinal examinations of premature infants of various birth weights and gestational ages. A total of 80 premature infants were enrolled for analysis. The mean postnatal age of infants at the time of diagnosis was 7.3 +/- 3.4 weeks for stage 1 retinopathy, 9.2 +/- 5.8 for stage 2 retinopathy, 9.5 +/- 3.8 for stage 3 retinopathy, 10.7 +/- 3.7 for threshold disease, and 11.7 +/- 3.2 for stage 4 retinopathy. The mean postconceptional age of infants at the time of diagnosis was 35 +/- 3 for stage 1 retinopathy, 36.4 +/- 3 for stage 2 retinopathy, 37.6 +/- 3.5 for stage 3 retinopathy, 38.4 +/- 3.5 for threshold disease, and 40 +/- 3.7 for stage 4 retinopathy. The age at the time of the initial detection of ROP was from the ninth to 10th week among infants weighing less than 1,000 g at birth and from the fifth to seventh week among those weighing 1,000 g or more at birth. However, the postconceptional age at the time of initial detection of ROP for the whole group was 36 weeks and was not influenced by birth weight or gestational age. Therefore, we suggest that postconceptional age, rather than postnatal age, should be used to decide the timing of retinal examinations for premature infants.
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Wang W, Chen HJ, Sun J, Benimetskaya L, Schwartz A, Cannon P, Stein CA, Rabbani LE. A comparison of guanosine-quartet inhibitory effects versus cytidine homopolymer inhibitory effects on rat neointimal formation. ANTISENSE & NUCLEIC ACID DRUG DEVELOPMENT 1998; 8:227-36. [PMID: 9669660 DOI: 10.1089/oli.1.1998.8.227] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Phosphorothioate oligodeoxynucleotides (PS oligos) manifest antisense and G-quartet aptameric inhibitory effects on vascular smooth muscle cell (SMC) proliferation. PS oligo cytidine homopolymers also have nonsequence-specific, non-G-quartet inhibitory effects on in vitro and in vivo SMC proliferation. In this study, we compared the effects of S-dC18 and S-dC28, 18-mer and 28-mer cytidine homopolymers, respectively, which lack guanosines, with those of ZK10, a G-tetrad forming compound, on in vitro SMC proliferation and in vivo neointimal formation. ZK10 significantly inhibited in vitro human aortic SMC proliferation. At the same molar concentration, ZK10 had significantly greater inhibitory potency on SMC proliferation than either S-dC18, S-dC28, or 7DG-ZK10, which is a modified ZK10 with ten 7-deaza guanosine substitutions. ZK10 was significantly more potent than S-dC18 and S-dC28 in inhibiting PDGF-induced in vitro SMC migration. S-dC18, S-dC28, and ZK10 treatment significantly reduced the intima/media area ratio after rat carotid artery balloon injury compared with the values of the control groups. ZK10 was a more potent inhibitor of neointimal formation than the same chain length S-dC18. ZK10 formed higher-order structures, as shown on gel electrophoresis, in contrast to S-dC28 and 7DG-ZK10. Therefore, the 18-mer ZK10 has comparable in vivo SMC inhibitory effects to the 28-mer S-dC28, a fact that may have ramifications for the development of optimal PS oligos to inhibit angioplasty restenosis.
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Huang HY, Huang CC, Lui CC, Chen HJ, Chen WJ. Isolated intracranial Rosai-Dorfman disease: case report and literature review. Pathol Int 1998; 48:396-402. [PMID: 9704347 DOI: 10.1111/j.1440-1827.1998.tb03923.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rosai-Dorfman disease, first described in 1969, is a rare idiopathic histioproliferative disease affecting the lymph nodes. Typical clinical features include bilateral painless lymphadenopathy, fever and polyclonal hypergammaglobulinemia. In approximately 43% of cases, extranodal sites may be involved and occasionally represent the initial or sole manifestation of the disease. Central nervous system manifestations are exceedingly rare, and only 17 cases have been recorded, among which there are merely seven isolated intracranial cases without concurrent nodal or other extranodal involvement. Herein, we report a 38-year-old male presenting with generalized tonic-clonic seizure and radiological findings indicative of meningioma. Complete physical examinations and laboratory surveys demonstrate the absence of involvement at other body sites. Microscopically, the lesion consists of proliferative histiocytes exhibiting emperipolesis coupled with the characteristic cytoplasmic staining against S-100 protein. The differential diagnosis of polymorphic inflammatory meningioma-mimicking masses is discussed, and a review of previously reported intracranial Rosai-Dorfman disease is presented.
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Chen HJ, Rojas-Soto M, Oguni A, Kennedy MB. A synaptic Ras-GTPase activating protein (p135 SynGAP) inhibited by CaM kinase II. Neuron 1998; 20:895-904. [PMID: 9620694 DOI: 10.1016/s0896-6273(00)80471-7] [Citation(s) in RCA: 444] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Ca2+ influx through N-methyl-D-aspartate- (NMDA-) type glutamate receptors plays a critical role in synaptic plasticity in the brain. One of the proteins activated by the increase in Ca2+ is CaM kinase II (CaMKII). Here, we report a novel synaptic Ras-GTPase activating protein (p135 SynGAP) that is a major component of the postsynaptic density, a complex of proteins associated with synaptic NMDA receptors. p135 SynGAP is almost exclusively localized at synapses in hippocampal neurons where it binds to and closely colocalizes with the scaffold protein PSD-95 and colocalizes with NMDA receptors. The Ras-GTPase activating activity of p135 SynGAP is inhibited by phosphorylation by CaMKII located in the PSD protein complex. Inhibition of p135 SynGAP by CaMKII will stop inactivation of GTP-bound Ras and thus could result in activation of the mitogen-activated protein (MAP) kinase pathway in hippocampal neurons upon activation of NMDA receptors.
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Chen HJ, Gonzalez FJ, Shou M, Chung FL. 2,3-epoxy-4-hydroxynonanal, a potential lipid peroxidation product for etheno adduct formation, is not a substrate of human epoxide hydrolase. Carcinogenesis 1998; 19:939-43. [PMID: 9635886 DOI: 10.1093/carcin/19.5.939] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Our previous studies have shown that 2,3-epoxy-4-hydroxynonanal, a reactive epoxy aldehyde capable of forming etheno adducts with DNA bases, is mutagenic and tumorigenic (Carcinogenesis, 14, 2073). The epoxy aldehyde can be generated from trans-4-hydroxy-2-nonenal, a lipid peroxidation product of omega-6 polyunsaturated fatty acids, by autoxidation or by incubation with fatty acid hydroperoxides or hydrogen peroxides (Chem. Res. Toxicol., 9, 306). These are plausible in vivo pathways for the formation of 2,3-epoxy-4-hydroxynonanal. The possibility that 2,3-epoxy-4-hydroxynonanal is a tumorigen of endogenous origin is suggested by recent observations that etheno bases are detected as background DNA lesions in untreated rodents and humans. A metabolic pathway critical for detoxification of 2,3-epoxy-4-hydroxynonanal involves the ring-opening by epoxide hydrolase, which abolishes its ability to form cyclic etheno DNA adducts. In this study, we examined whether 2,3-epoxy-4-hydroxynonanal is a substrate of cDNA expressed human epoxide hydrolase. Human epoxide hydrolase was expressed in TK- 143 cells (thymidine kinase-deficient human embryoblast) infected with recombinant vaccinia virus encoding human epoxide hydrolase cDNA. Controls consisted of the cells infected with vaccinia virus in the absence of human epoxide hydrolase cDNA. No hydrolysis occurred when [2,3-(3)H]2,3-epoxy-4-hydroxynonanal was incubated at 37 degrees C for 30 min at pH 7.4 with cells expressing human epoxide hydrolase, as indicated by the presence of a pair of radioactive peaks in reversed-phase HPLC chromatography, which comigrated with the UV standards of the two diastereomers of the epoxy aldehyde. The identity of these compounds as the intact epoxy aldehyde was further supported by derivatization to the 2,4-dinitrophenylhydrazones followed by reversed phase HPLC analysis. Similar results were observed with the control cells or with the heat deactivated human epoxide hydrolase. The epoxide hydrolase activity in the expressed cells was demonstrated by their ability to convert benzo[a]pyrene-4,5-dihydroepoxide to benzo[a]pyrene-trans-4,5-dihydrodiol under the same conditions. These results clearly indicate that 2,3-epoxy-4-hydroxynonanal is not a substrate of human epoxide hydrolase, and, thus strengthen its possible endogenous role in the formation of promutagenic exocyclic etheno adducts in vivo.
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Lee TC, Yang LC, Chen HJ. Effect of patient position and hypotensive anesthesia on inferior vena caval pressure. Spine (Phila Pa 1976) 1998; 23:941-7; discussion 947-8. [PMID: 9580963 DOI: 10.1097/00007632-199804150-00019] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
STUDY DESIGN This is a prospective study to measure the inferior vena caval pressure of 20 patients in different positions and different states of blood pressure. OBJECTIVES Because the inferior vena caval pressure could affect the vertebral venous pressure, which in turn may influence blood loss during lumbar spinal surgery, this study was designed to provide the quantitative data necessary to stress the importance of patient positioning and to assess the effect of controlled hypotension on inferior vena caval pressure. SUMMARY OF BACKGROUND DATA Positioning patients with a pendulous abdomen and controlled hypotension has been practiced widely during lumbar spinal surgery. It is generally believed that the former will help reduce vertebral venous engorgement and the latter will produce a bloodless surgical wound. However, there have been no complete studies in which quantitative changes of inferior vena caval pressure resulting from different positions was examined. In addition, it would be interesting to know what happens to inferior vena caval pressure during induced hypotension. Could there be an adverse effect on the inferior vena caval pressure during the hypotensive state? METHODS An intravenous catheter was introduced into the inferior vena cava in each of 20 patients undergoing spinal surgery. In each patient, the inferior vena caval pressure was measured when the patient was supine, prone on a conventional pad, and prone on a Relton-Hall frame. It was followed by isoflurane-induced hypotension with reduction of mean arterial pressure by 20 mm Hg. RESULTS In this series, the inferior vena caval pressure ranged from 8.2 to 23.4 mm Hg (with a mean of 15.3 mm Hg) when patients were positioned prone on a conventional pad. However, when they were subsequently positioned prone on a Relton-Hall frame, the inferior vena caval pressure decreased dramatically to a range of 4.6 to 13.6 mm Hg (with a mean of 8.2 mm Hg). In each patient the measured inferior vena caval pressure when positioned prone on a conventional pad was 1.5 times greater than that measured with the patient positioned on a Relton-Hall frame. There was a statistically significant difference between these two positions (F = 75.996; P < 0.05). The patients' mean arterial pressure ranged from 92 to 105 mm Hg before induced hypotension. During this time, the inferior vena caval pressure ranged from 4.1 to 13.1 mm Hg (mean, 8.2 mm Hg). During the hypotensive state, the patients' inferior vena caval pressure was found to range from 4.2 to 13.6 mm Hg (mean, 8.1 mm Hg). In each patient the hypotensive interior vena caval pressure may be slightly higher or lower than the baseline pressure. However, the variation never exceeded 1.7 mm Hg. Statistically, there was no significant difference between these two periods (t = 0.956; P > 0.05). CONCLUSIONS A device allowing the patient's abdominaL viscera to hang freely while the patient is in a prone position significantly reduces their inferior vena caval pressure. The patients also has a constant inferior vena caval pressure during isoflurane-induced hypotension.
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Barraclough R, Chen HJ, Davies BR, Davies MP, Ke Y, Lloyd BH, Oates A, Rudland PS. Use of DNA transfer in the induction of metastasis in experimental mammary systems. BIOCHEMICAL SOCIETY SYMPOSIUM 1998; 63:273-94. [PMID: 9513730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The metastatic spread of cancer is a little understood process, in part because it is difficult to model the entire process using experimental approaches in vitro. The ability to transfer DNA into non-metastatic mammary cells and to observe the induction of metastasis in vivo provides a means for identifying DNA sequences that are associated with the development of metastatic capability. Using these techniques, a metastasis-associated cytoskeletal calcium binding protein, S100A4 (p9Ka), has been identified as an inducer of metastatic capability in benign rat mammary epithelial cells. Metastasis can also be induced in the rat mammary epithelial cells by fragments of DNA from metastatic, but not from benign, human breast tumour cells. These non-coding fragments of DNA act via the induction of osteopontin, an extracellular, integrin binding, calcium binding protein. Since both osteopontin and S100A4 are thought to be associated with malignancy in human breast cancer specimens, gene transfer techniques can identify genes for metastasis-inducing proteins that may play a role in breast cancer, and further suggest that cell migration/motility might be important in the metastatic process.
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Wang W, Chen HJ, Schwartz A, Cannon PJ, Stein CA, Rabbani LE. Inhibitory nonsequence-specific effects of cytidine homopolymers on in vivo neointimal formation. ANTISENSE & NUCLEIC ACID DRUG DEVELOPMENT 1997; 7:559-66. [PMID: 9450913 DOI: 10.1089/oli.1.1997.7.559] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Phosphorothioate oligodeoxynucleotides (PS oligos) manifest both antisense and G-quartet aptameric inhibitory effects on vascular smooth muscle cell (SMC) proliferation. In this study, we examined the effects of three cytidine (S-dC) homopolymers lacking any guanosines of various chain length-S-dC28, S-dC18 and S-dC12-on in vitro SMC proliferation and in vivo neointimal formation. S-dC18 significantly inhibited human vascular SMC proliferation, although it had only half the potency as the same dose of S-dC28. Furthermore, S-dC12 at the same concentrations as S-dC18 did not significantly inhibit vascular SMC proliferation. S-dC28 and S-dC18 inhibited PDGF-induced in vitro SMC migration, whereas D-dC12 had no significant effect on PDGF-induced in vitro SMC migration. We determined the effects of S-dC28, S-dC18, and S-dC12 on neointimal SMC formation in the rat carotid balloon injury model. Rat carotid artery neointimal formation after balloon injury was significantly attenuated by S-dC28 treatment compared with the control group and by S-dC18 treatment compared with the control group. S-dC28 and S-dC18 treatment significantly reduced the intima/media area ratio compared with the values of the control groups. However, S-dC12 did not significantly inhibit neointimal formation. We investigated the time course of the inhibitory effects of S-dC28 on rat carotid artery neointimal formation. S-dC28 significantly inhibited rat carotid artery intimal area and intima/media area ratio at 4 weeks and 8 weeks. Fluoresceinated S-dC28 (FITC-S-dC28) was found to be present throughout the rat carotid arterial wall within 6 hours after balloon injury. Taken together, the potent non-G-quartet, nonsequence-specific inhibitory effects of S-dC compounds on in vitro SMC proliferation and in vivo neointimal formation in the rat carotid balloon injury model are chain length dependent and long lasting.
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Chen HJ, Smith DL, Starrett DA, Zhou D, Tucker ML, Solomos T, Gross KC. Cloning and characterization of a rhamnogalacturonan hydrolase gene from Botrytis cinerea. BIOCHEMISTRY AND MOLECULAR BIOLOGY INTERNATIONAL 1997; 43:823-38. [PMID: 9385443 DOI: 10.1080/15216549700204641] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Rhamnogalacturonan hydrolase (Rgase A) cleaves alpha 1--2 linkages between rhamnosyl and galacturonosyl residues in pectin. A 1.9 kb RGase A cDNA clone (BCRHGA) was isolated from a B. cinerea cDNA library using a PCR-amplified Aspergillus aculeatus RGase A probe. It's 1.7 kb open reading frame had 62% identity at the amino acid level with A. aculeatus RGase A. Northern blots of B. cinerea total RNA probed with BCRHGA revealed a 2 kb band, suggesting the cDNA clone is full or nearly-full length. To determine mRNA expression of the gene, B. cinerea was grown in media containing 0.5% apple pectin, 0.5% rhamnogalacturonan-I and 1% glucose carbon sources. Northern analysis revealed the BCRHGA gene was expressed on all carbon sources, but with different patterns of expression. B. cinerea RGase A appeared to be coded for by a single or low copy number gene based on Southern analysis.
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Kim J, Johnson K, Chen HJ, Carroll S, Laughon A. Drosophila Mad binds to DNA and directly mediates activation of vestigial by Decapentaplegic. Nature 1997; 388:304-8. [PMID: 9230443 DOI: 10.1038/40906] [Citation(s) in RCA: 419] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The TGF-beta (transforming growth factor-beta)-related signalling proteins, including Decapentaplegic (Dpp) in Drosophila-and bone morphogenic proteins and activin in vertebrates, affect the growth and patterning of a great variety of structures. However, the mechanisms by which these ligands regulate gene expression are not understood. Activation of complexes of type I with type II receptors results in the phosphorylation and nuclear localization of members of the SMAD protein family, which are thought to act as co-activators of transcription, perhaps in conjunction with sequence-specific cofactors. Here we show that the amino-terminal domain of the Drosophila Mothers against dpp protein (Mad), a mediator of Dpp signalling, possesses a sequence-specific DNA-binding activity that becomes apparent when carboxy-terminal residues are removed. Mad binds to and is required for the activation of an enhancer within the vestigial wing-patterning gene in cells across the entire developing wing blade. Mad also binds to Dpp-response elements in other genes. These results suggest that Dpp signalling regulates gene expression by activating Mad binding to target gene enhancers.
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Grant DM, Hughes NC, Janezic SA, Goodfellow GH, Chen HJ, Gaedigk A, Yu VL, Grewal R. Human acetyltransferase polymorphisms. Mutat Res 1997; 376:61-70. [PMID: 9202739 DOI: 10.1016/s0027-5107(97)00026-2] [Citation(s) in RCA: 158] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Conjugation of primary amino and hydroxylamino groups with acetate, catalyzed by acetyl CoA-dependent arylamine acetyltransferase (NAT) enzymes, may play an important role in the intricate series of metabolic pathways that produce or prevent toxicity following exposure to homo- and heterocyclic arylamine and hydrazine xenobiotics. Two independently regulated and kinetically distinct human acetyltransferases are now known to exist, namely NAT1 and NAT2. Interindividual variation in NAT2 function is associated with the classical isoniazid acetylation polymorphism which was discovered over forty years ago. At last count, fifteen variant alleles at the NAT2 gene locus have been linked to the isoniazid 'acetylator phenotype', and each of these can be identified in population studies using specific PCR-based genotyping tests. On the other hand, NAT1 shows kinetic selectivity for compounds whose disposition is unrelated to the classical isoniazid acetylation polymorphism. NAT1 expression is also phenotypically variable in human populations, at least in part due to allelic differences at the NAT1 gene locus. Nine NAT1 variant alleles have been described to date, of which NAT1* 14 and NAT1* 15 clearly produce defective NAT1 proteins and lead to functional impairment in the metabolism of NAT1-selective substrates both in vivo and in vitro. On the other hand, it has been reported that the NAT1* 10 variant associates with elevated NAT1 activity and increased risk for cancers of the bladder and colon. Because of the important toxicologic consequences of allelic variation in NAT1 and NAT2 function for the metabolic activation of arylamine and heterocyclic amine procarcinogens, further studies are needed to improve our understanding of the extent of NAT allelic variation, to determine the functional capacity of each variant gene product, and to develop accurate methods of detecting them in population and epidemiological studies.
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Wang W, Chen HJ, Warshofsky M, Schwartz A, Stein CA, Rabbani LE. Effects of S-dC28 on vascular smooth muscle cell adhesion and plasminogen activator production. ANTISENSE & NUCLEIC ACID DRUG DEVELOPMENT 1997; 7:101-7. [PMID: 9149845 DOI: 10.1089/oli.1.1997.7.101] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We sought to examine phosphorothioate oligodeoxynucleotide (PS oligo) non-G-quartet, nonsequence specific effects on smooth muscle cell (SMC) adhesion by using S-dC28, a 28-mer cytidine homopolymer that lacks contiguous guanosine residues. Human aortic SMC were incubated with vehicle or various doses of S-dC28, and the number of SMC adhered to noncoated plates was determined using a Coulter Counter. S-dC28 significantly inhibited SMC adhesion. SMC adhesion dramatically improved with S-dC28 in fibronectin-coated plates. When laminin-coated plates were used, the inhibition of SMC adhesion by S-dC28 was completely reversed. Replacement of serum-free medium with 5% fetal bovine serum medium for SMC cultured on non-coated plates also greatly attenuated inhibition of adhesion by S-dC28. Human SMC TPA, UPA, and PAI-1 antigen levels were determined by ELISAs. PDGF significantly induced SMC TPA antigen production measured by an ELISA. Coincubation of PDGF with S-dC28 significantly attenuated SMC TPA antigen levels. SMC UPA antigen levels after coincubation with PDGF and S-dC28 were significantly greater than the values observed in SMC incubated in medium containing PDGF alone. SMC PAI-1 antigen levels were not altered by the addition of S-dC28. We conclude that S-dC28 inhibits human SMC adhesion and that this inhibition can be diminished by fibronectin or laminin coating of culture plates or by the presence of serum in the culture medium. Furthermore, S-dC28 attenuates SMC TPA production, thereby inhibiting SMC migration, whereas S-dC28 augments SMC UPA production, thus diminishing SMC cellular adhesion.
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Chen HJ, Yuan J, Lobel P. Systematic mutational analysis of the cation-independent mannose 6-phosphate/insulin-like growth factor II receptor cytoplasmic domain. An acidic cluster containing a key aspartate is important for function in lysosomal enzyme sorting. J Biol Chem 1997; 272:7003-12. [PMID: 9054390 DOI: 10.1074/jbc.272.11.7003] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We have used systematic mutational analysis to identify signals in the 166-residue murine cation-independent mannose 6-phosphate/insulin-like growth factor II receptor cytoplasmic domain required for efficient sorting of lysosomal enzymes. Alanine cluster mutagenesis on all conserved residues apart from the endocytosis signal demonstrates that the major sorting determinant is a conserved casein kinase II site followed by a dileucine motif (157DDSDEDLL164). Small deletions or additions outside this region have severe to mild effects, indicating that context is important. Single residue mutagenesis indicates that cycles of serine phosphorylation/dephosphorylation are not obligatory for sorting. In addition, the two leucine residues and four of the five negatively charged residues can readily tolerate conservative substitutions. In contrast, aspartate 160 could not tolerate isoelectric or isosteric substitutions, implicating it as a critical component of the sorting signal.
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Ker CG, Kuo KK, Chen HJ, Chen JS, Lee KT, Sheen PC. Morphology of intrahepatic duct in surgical treatment of hepatolithiasis. HEPATO-GASTROENTEROLOGY 1997; 44:317-21. [PMID: 9164497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
BACKGROUND/AIMS Surgery is the usual treatment for hepatolithiasis. However, the method of choice is based on intrahepatic duct morphology. MATERIAL AND METHODS Six hundred sixty-two patients with hepatolithiasis were operated on in the period between 1980-1994. Hepatolithiasis was clinically classified into primary (75.8%) and secondary (24.2%) types. RESULTS Patients treated between 1990-1994 (35.9%), liver resection was performed in 71 patients (69 of left and 2 of the right liver). However, liver resection was chosen only in 6.7% (11/163) during the 1970s. Candidacy for liver resection increased recently due to the increase in primary type. According to the morphology of intrahepatic ducts, the location of stricture was classified into: Central type (n = 59, 30%), Segmental type (n = 101, 51%), and Subsegmental type (n = 21, 10.6%), and unclassified (n = 17, 8.4%). Liver resection was recommended for patients of segmental or subsegmental type. Choledocho-lithotomy with T-tube drainage was indicated in two third of the patients with hepatolithiasis. However, the incidence of post-operative retained stones was very high, and post-operative choledochoscopic lithotripsy was used to treat these post-operative problems easily. The mortality of this disease was 1% (2/198) in the 1990s compared with that of 4.1% (19/464) in 1980s and 10.1% (15/148) in 1970s. CONCLUSION We strongly recommend that liver resection for patients with adequate indications will have good results. In addition, one should pay attention to the abnormal pattern of intrahepatic ducts that are commonly found in patients with hepatolithiasis during liver resection. Liver resection is an ideal surgical method for the eradication of diseased lesions and to prevent malignant changes from bile duct with stones. Concise information concerning the anatomic structure was found to be important in determining post-operative results in the management of hepatolithiasis.
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Wang W, Chen HJ, Schwartz A, Cannon PJ, Rabbani LE. T cell lymphokines modulate bFGF-induced smooth muscle cell fibrinolysis and migration. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 272:C392-8. [PMID: 9124280 DOI: 10.1152/ajpcell.1997.272.2.c392] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Smooth muscle cell (SMC) fibrinolysis is necessary for SMC migration. To determine whether the T cell lymphokines interleukin 4 (IL-4) and interferon-gamma (IFN-gamma) modulate SMC fibrinolysis and migration induced by basic fibroblast growth factor (bFGF), we examined the effects of IL-4 and IFN-gamma on human SMC tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (UPA), and plasminogen activator inhibitor 1 (PAI-1) antigen production, determined by enzyme-linked immunosorbent assays. Although IL-4 had no effects on SMC tPA, UPA, and PAI-1 production, it potentiated bFGF-induced tPA, UPA, and PAI-1 antigens. IL-4 plus bFGF resulted in a net increase in SMC fibrinolytic activity. IFN-gamma did not significantly affect bFGF induction of SMC tPA and PAI-1 antigens. However, IFN-gamma significantly decreased bFGF-mediated induction of SMC UPA antigen. IFN-gamma decreased the IL-4 plus bFGF induction of both tPA and UPA antigens. IL-4 increased and IFN-gamma abrogated bFGF induction of in vitro SMC migration through a modified micro-Boyden chamber. Therefore, IL-4 and IFN-gamma modulate bFGF-mediated induction of in vitro vascular SMC fibrinolysis and migration.
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Erdman SE, Chen HJ, Burtis KC. Functional and genetic characterization of the oligomerization and DNA binding properties of the Drosophila doublesex proteins. Genetics 1996; 144:1639-52. [PMID: 8978051 PMCID: PMC1207715 DOI: 10.1093/genetics/144.4.1639] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The doublesex (dsx) gene of Drosophila melanogaster encodes both male-specific (DSXM) and female-specific (DSXF) polypeptides, which are required for normal differentiation of numerous sexually dimorphic somatic traits. The DSX polypeptides are transcription factors and have been shown previously to bind through a zinc finger-like domain to specific sites in an enhancer regulating sex-specific expression of yolk protein genes. We have determined the consensus target sequence for this DNA binding domain to be a palindromic sequence AGNNACTAAATGTNNTC composed of two half-sites around a central (A/T) base pair. As predicted by the symmetric nature of this site, we have found that the DSX proteins exist as dimers in vivo and have mapped two independent dimerization domains by the yeast two-hybrid method; one in the non-sex-specific amino-terminal region of the protein and one that includes the partially sex-specific carboxy-terminal domains of both the male and female polypeptides. We have further identified a missense mutation that eliminates dsx function in female flies, and shown that the same mutation prevents dimerization of DSXF in the yeast two-hybrid system, indicating a critical role for dimerization in dsx function in vivo.
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Abstract
The authors describe the case of a 53-year-old woman who suffered from a hemifacial spasm caused by a venous angioma in the posterior fossa. At operation the parenchymal segment of the angioma was preserved and vascular decompression was performed by placing pieces of shredded Teflon between the vessel and nerve. After decompression the patient was completely free from spasm.
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Pan BT, Shi JP, Chen HJ, Roberts C, Chen DH, Wang JW. Identification of a potential physiological substrate for oncogenic Ras-activated protein kinases in activated Xenopus egg extracts: correlation with oncogenic Ras-induced cell cycle arrest. J Cell Physiol 1996; 169:149-58. [PMID: 8841431 DOI: 10.1002/(sici)1097-4652(199610)169:1<149::aid-jcp15>3.0.co;2-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Activated Xenopus egg extracts are capable of undergoing cell-free cell cycling. Using these activated extracts, we previously showed that purified, bacterially expressed oncogenic human RasH protein arrests cell cycle progression. Because oncogenic Ras activates many serine/threonine protein kinases in Xenopus oocytes and egg extracts, it is possible that induction of cell cycle arrest involves the action of oncogenic Ras-activated kinases. Thus, the identification of the physiological substrates for oncogenic Ras-activated kinases is important for elucidating the molecular mechanism underlying oncogenic Ras-induced cell cycle arrest. We used 32P-orthophosphate as a label to identify the potential substrates. Our results demonstrated that the 32P-labeling of both a 32 and a 33 kDa protein were greatly enhanced by oncogenic Ras during the incubation of activated Xenopus egg extracts. The enhanced labeling correlated with the induced cell cycle arrest and was contributed by serine phosphorylation. Moreover, the 33 kDa protein was detected only in the presence of oncogenic Ras and was a serine-hyperphosphorylated form of the 32 kDa protein. Furthermore, new protein synthesis was not required for the enhanced labeling, consistent with the concept that the enhanced serine phosphorylation of the 32 kDa protein is by oncogenic Ras-activated protein kinases. In addition to serine phosphorylation, our results also suggested that an as yet unidentified modification of the 32 kDa protein might also be induced by oncogenic Ras. Our results suggest that the 32 kDa protein is a potential physiological substrate for oncogenic Ras-activated protein kinases.
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Yian MT, Chen HJ, Chu TY, Yin CS. Postcoital hemoperitoneum without identifiable bleeding source: a case report. ZHONGHUA YI XUE ZA ZHI = CHINESE MEDICAL JOURNAL; FREE CHINA ED 1996; 58:291-3. [PMID: 8994336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Spontaneous intra-abdominal bleeding has been called abdominal apoplexy. It has been so named because its nature and spontaneity closely resemble those of its more common cerebral counterpart. The bleeding source commonly came from a ruptured branch of celiac axis or superior mesenteric artery. Rarely, hemoperitoneum occurs spontaneously post coitus without evident vaginal injury. There were only twelve cases reported in the medical literature to date. Nearly, all of them showed injury of pelvic organs including round or broad ligaments, ovarian cysts or adhesion bands. A case of massive hemoperitoneum after coitus, with no definite bleeding source, is reported.
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Chung FL, Chen HJ, Nath RG. Lipid peroxidation as a potential endogenous source for the formation of exocyclic DNA adducts. Carcinogenesis 1996; 17:2105-11. [PMID: 8895475 DOI: 10.1093/carcin/17.10.2105] [Citation(s) in RCA: 262] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A number of promutagenic exocyclic DNA adducts have recently been detected in both humans and rodents without carcinogen treatment. These observations raised questions about their origins and potential significance in carcinogenesis. In this commentary, we present our views pertaining to the in vivo sources of these cyclic adducts, specifically the cyclic propano and etheno adducts. The basis for our discussion comes mainly from the information generated through a span of more than a decade from several laboratories, including ours. This commentary summarizes the data from the chemical and biochemical studies that provide support for the hypothesis that lipid peroxidation is involved in the endogenous formation of these exocyclic adducts.
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Abstract
The case of an interdural arachnoid cyst of traumatic origin at the C3-5 level in an 18-year-old man was admitted to our hospital with a 1-year history of progressive weakness in left limbs and numbness below the clavicles is reported. He had had a C-2 fracture at the age of 9 years without definite neurological deficits. Magnetic resonance imaging revealed a cystic lesion in the C3-5 level. Laminectomy was performed, and an interdural cyst was found. Histological examination revealed fibrous thickening of the arachnoid membrane. A cyst located in the interdural space of upper cervical spine is extremely rare.
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