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Liu W, Gu N, Feng G, Li S, Bai S, Zhang J, Shen T, Xue H, Breen G, St Clair D, He L. Tentative association of the serotonin transporter with schizophrenia and unipolar depression but not with bipolar disorder in Han Chinese. PHARMACOGENETICS 1999; 9:491-5. [PMID: 10780268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
The serotonin transporter gene (SERT) plays an important role in the serotonin uptake into neurons. Recently, several polymorphisms including a variable-number-tandem-repeat (VNTR) in the second intron and an insertion/deletion polymorphism (5-HTT linked polymorphic region, 5-HTTLPR) were identified and reported to be associated with a variety of mental illnesses, including major depression, bipolar disorder, anxiety-related traits, and autism. In our study, we performed an association study between the SERT VNTR polymorphism and schizophrenia (n = 260), bipolar disorder (n = 137), and unipolar depression (n = 33) in the Han Chinese. A large group of ethnically matched control individuals (n = 362) were also genotyped. Allele 12 of the VNTR polymorphism was associated with schizophrenia (P = 0.007) and unipolar depression (P = 0.011). Bipolar disorder was not associated with the VNTR (P = 0.93). Thus, we conclude that the SERT VNTR polymorphism may be a risk factor for both schizophrenia and unipolar depression, but not for bipolar disorder, in the Han Chinese.
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202
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Kelly MK, Miller KF, Fang G, Feng G. When days are numbered: calendar structure and the development of calendar processing in English and Chinese. J Exp Child Psychol 1999; 73:289-314. [PMID: 10419645 DOI: 10.1006/jecp.1999.2503] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Unlike English, Chinese uses a numerical system for naming months and days. This study explored whether this difference in naming affects the development of simple calendar calculation. Eight- and 10-year-old children as well as undergraduates in China and the United States were asked to name the day or month that comes a specified time before or after a given day or month. In each age group Chinese speakers primarily used calculation based on calendar names to solve these tasks, while English speakers primarily resorted to reciting the names. The magnitude of these differences was substantial; on difficult tasks Chinese fourth graders performed at speeds comparable to those of English-speaking adults. Implications for models of how linguistic structure affects cognition are discussed.
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203
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Yuang Z, Yang P, Feng G. [Study of the local anatomy and clinical practice about rhytidectomy of nasolabial fold]. ZHONGHUA ZHENG XING SHAO SHANG WAI KE ZA ZHI = ZHONGHUA ZHENG XING SHAO SHANG WAIKF [I.E. WAIKE] ZAZHI = CHINESE JOURNAL OF PLASTIC SURGERY AND BURNS 1999; 15:271-3. [PMID: 11593603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
OBJECTIVE A technique is introduced to improve the operative result of rhytidectomy of the nasolabial fold. METHODS Regional anatomy was studied on 10 adult cadavers together with histological examinations of tissue sections to investigate the formation mechanism of the nasolabial fold. 13 patients were operated on using a new technique of nasolabial fold rhytidectomy. RESULTS Prolonged and repeated movements of the facial mimetic muscles produce a shearing force between the skin-subcutaneous tissue and the SMAS-mimetic muscles, causing relative motion of adjacent tissues with different structure at the site of the nasolabial fold, thus producing the nasolabial fold. In clinical application of the finding, the nasolabial folds of 13 patients were corrected with remarkable early and long-term results postoperatively. CONCLUSION The operation should be performed between SMAS and the subcutaneous tissue. SMAS should be incised along the zygomatic major muscle. The fibro-fatty zygomatic pad should be replaced anatomically and the zygomatic ligament be reconstructed.
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204
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Harris RS, Feng G, Ross KJ, Sidhu R, Thulin C, Longerich S, Szigety SK, Hastings PJ, Winkler ME, Rosenberg SM. Mismatch repair is diminished during stationary-phase mutation. Mutat Res 1999; 437:51-60. [PMID: 10425389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
This paper is an invited Response to a recent Commentary [P.L. Foster, Rev. Mut. Res. 436 (1999) 179-184] entitled "Are adaptive mutations due to a decline in mismatch repair? The evidence is lacking". The Commentary argues that no evidence exists supporting the idea that mismatch repair is limiting specifically during stationary-phase mutation. A primary concern of the author is to question the method that we used previously to measure growth-dependent mutation. In this method, mutation rates are calculated using counts of mutant colonies taken at times when those colonies arise, rather than at a predetermined, fixed time. Here we show further data that illustrate why this must be done to ensure accurate mutation measurements. Such accuracy was necessary for our published determination that mismatch repair proteins are not limiting during growth-dependent mutation, but become so during stationary-phase mutation. We review the evidence supporting the idea that stationary-phase reversion of a lac frameshift mutation occurs in an environment of decreased mismatch repair capacity. Those data are substantial. The data presented in the Commentary, in apparent contradiction to this idea, do not justify the conclusion presented there.
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205
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Li Y, Feng G, Yi Y, Lin J. [The experimental investigation of epithelial healing in rabbit central corneal alkali wounds]. YAN KE XUE BAO = EYE SCIENCE 1999; 15:74-7. [PMID: 12579703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
PURPOSE To observe the morphologic changes of epithelium in the alkali wounds at the central corneal of rabbits. METHODS 38 rabbits weighing 2.5 kg were used. A alkali wound of the corneas was performed in the right eye of 38 New Zealand white rabbits with round filter paper, 8 mm in diameter, which were soaked in 0.5 mol/L NaOH for 5 seconds and then were placed centrally on the cornea for 60 seconds. The corneal burns were examined and photographed after the staining of 2% fluoresent staining with a slit lamp every day. The excised corneas were examined in the light microscope, electron microscope. RESULTS The epithelial cells had rapidly disappeared in the burned area. The epithelial cells regrowth started at 8 hours following the burn, and 1-2 layers epithelial cells covered the burned area by 24 hours. The epithelial defects occured again on the 4th day. The desmosome and microvilli of the regenerating epithelium had a reduced number. There was no basement membrane between the regenerating epithelium and the strom. There were increased intercellular spaces between the regenerating epithalial cells. CONCLUSION The epithelial healing were achieved through the division and migration of epithelial cells at the margin of the wound in rabbit central corneal alkali wound. The decrease of the junctions and the increase of intercellular spaces between the regenerating epithalial cells may be responsible for the second epithelial defects.
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206
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Zhang B, Feng G, He H, Zhang D, Li T, Li S, Wei Q, He Y, Huang P. [Study on cultivation of Dendrobium flexicaule by habitat imitation]. ZHONG YAO CAI = ZHONGYAOCAI = JOURNAL OF CHINESE MEDICINAL MATERIALS 1999; 22:217-20. [PMID: 12575071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
Dendrobium drug, a rare medicinal herb, reproduces differcut for growth environment to lead rare resources. By studying of cultivation for many many years in Fuliu mountain area, authors had found out the cultivated method simulating the habitat of wild Dendrobium flexicaule. The results could supply a basis for its development and utilization.
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Feng G, Krejci E, Molgo J, Cunningham JM, Massoulié J, Sanes JR. Genetic analysis of collagen Q: roles in acetylcholinesterase and butyrylcholinesterase assembly and in synaptic structure and function. J Cell Biol 1999; 144:1349-60. [PMID: 10087275 PMCID: PMC2150590 DOI: 10.1083/jcb.144.6.1349] [Citation(s) in RCA: 138] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Acetylcholinesterase (AChE) occurs in both asymmetric forms, covalently associated with a collagenous subunit called Q (ColQ), and globular forms that may be either soluble or membrane associated. At the skeletal neuromuscular junction, asymmetric AChE is anchored to the basal lamina of the synaptic cleft, where it hydrolyzes acetylcholine to terminate synaptic transmission. AChE has also been hypothesized to play developmental roles in the nervous system, and ColQ is also expressed in some AChE-poor tissues. To seek roles of ColQ and AChE at synapses and elsewhere, we generated ColQ-deficient mutant mice. ColQ-/- mice completely lacked asymmetric AChE in skeletal and cardiac muscles and brain; they also lacked asymmetric forms of the AChE homologue, butyrylcholinesterase. Thus, products of the ColQ gene are required for assembly of all detectable asymmetric AChE and butyrylcholinesterase. Surprisingly, globular AChE tetramers were also absent from neonatal ColQ-/- muscles, suggesting a role for the ColQ gene in assembly or stabilization of AChE forms that do not themselves contain a collagenous subunit. Histochemical, immunohistochemical, toxicological, and electrophysiological assays all indicated absence of AChE at ColQ-/- neuromuscular junctions. Nonetheless, neuromuscular function was initially robust, demonstrating that AChE and ColQ do not play obligatory roles in early phases of synaptogenesis. Moreover, because acute inhibition of synaptic AChE is fatal to normal animals, there must be compensatory mechanisms in the mutant that allow the synapse to function in the chronic absence of AChE. One structural mechanism appears to be a partial ensheathment of nerve terminals by Schwann cells. Compensation was incomplete, however, as animals lacking ColQ and synaptic AChE failed to thrive and most died before they reached maturity.
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208
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Wu X, Jiang S, Lin S, Tang G, Feng G, Qian Y, Wang D, Ren D, Gu N. No association between the intronic presenilin 1 polymorphism and Alzheimer's disease in the Chinese population. AMERICAN JOURNAL OF MEDICAL GENETICS 1999; 88:1-3. [PMID: 10050959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Wragg et al. [1996: Lancet 347:509-512] recorded an association between the intron-based presenilin 1 (PS1) genotype 1/1 and late-onset Alzheimer's disease (AD). This study was performed to determine if there is a similar association in the Chinese population. Ninety-one AD cases, 50 multiinfarct dementia (MID) patients, and 73 age-matched normal controls were recruited. Genotyping of PS1 and apolipoprotein E (APOE) was performed by the methods of polymerase chain reaction and restriction fragment length polymorphism. In AD, MID, and normal controls PS1 allele 1 frequency was 0.6703, 0.5600, and 0.6301, respectively; PS1 allele 2 frequency was 0.3297, 0.4400, and 0.3699, respectively. No association was detected between these diseases and any PS1 allele or genotype. There was only a nearly significant negative association between MID and PS1 genotype 1/1 in the subgroup population bearing APOE allele E4 (odds ratio = 0.2753, P = 0.0776). Our results do not support the conclusion that the intronic PS1 polymorphism is associated with Alzheimer's disease.
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209
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Yang L, Kong X, Liu D, Xiao X, Feng G. Preliminary clinical application of contrast-enhanced MR portography. Curr Med Sci 1999; 19:323-7. [PMID: 12938529 DOI: 10.1007/bf02886974] [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] [Received: 11/27/1998] [Indexed: 11/26/2022]
Abstract
The clinical application of contrast enhanced (CE) MR was evaluated. A total of 66 CE MR portograms were obtained by performing fast imaging with steady procession (FISP) technique on a 1.5-T Siemens magnetom vision. A maximum intensity projection algorithm was also employed to include all vessels in a single image. The patency of portal venous system, the presence and extent of varices were also evaluated. The results showed that all images had diagnostic quality. Main portal vein (MPV) and its 4th-6th level intrahepatic branches were visualized in 10 normal persons serving as control. The diameter of MPV, splenic vein and superior mesenteric vein was 1.02 +/- 0.21, 0.8 +/- 0.15, 0.8 +/- 0.26 cm respectively, which were significantly lower than that in portal hypertension patients (1.38 +/- 0.27, 1.26 +/- 0.18, 1.24 +/- 0.18 cm, respectively). In 23 preoperative cases of portal hypertension, dilated portal vein and tortuous enlarged splenic vein were found in 23 cases; esophageal and coronary varices in 12 and 19 cases, respectively. In 7 postoperative re-examined cases with portal hypertension, the flow velocity and flow of MPV were decreased in all cases and esophageal varices could still be observed in 3 cases. New vessels appeared in the great curvature of stomach in 2 cases. In 20 cases of liver carcinoma, occlusion of MPV or its intrahepatic branches were showed in 14, compression and dislocation of intrahepatic portal vein were found in 6. In other 6 cases, 2 were splenic venous thrombosis and 4 were tumors in the intestine or retro-peritoneum. It is concluded that three-dimensional CE MR portography is an accurate technique for evaluating the portal venous system. It is a reliable and noninvasive technique that can provide important information for the evaluation of patients' condition before TIPSS and liver transplantation.
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Xu L, Wu Y, Feng G, Oguchi M, Yokota H, Nakagawa T, Yamamoto I. Endovascular irradiation prevents smooth muscle cell proliferation and neointimal hyperplasia in rabbits. Curr Med Sci 1999; 19:240-5. [PMID: 12840905 DOI: 10.1007/bf02887745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/1998] [Indexed: 10/19/2022]
Abstract
The present study examined the temporal responses and the efficacy of 192Ir-HDR endovascular irradiation for preventing smooth muscle cell proliferation of rabbit iliac arteries after PTA with a cutting balloon catheter. Endovascular irradiation with 12 Gy was randomly performed on the one side of iliac arterial segment with the unirradiated side serving as a control. Animals were euthanatized 1, 2, 3, 4, 8 and 12 week(s) after angioplasty. Histopathological and immunohistochemical studies were carried out. Histopathology showed repair of the dissection by cellular accumulation and a striking reduction in the amount of neointimal hyperplasia in the irradiated arteries as compared with control vessels. A peak of PCNA-positive ratio was in neointima of the control arterial segments at a week. 2-4 weeks after irradiation, the neointimal PCNA-positive ratio was still significantly increased in the control arterial segments compared with the irradiated arterial segments. After 8 weeks, PCNA-positive ratio was below 1% in both irradiated arterial segments and the control. Our results showed that the 192Ir-HDR afterloading irradiation with a dose of 12 Gy can be considered sufficient for inhibiting neointimal hyperplasia in angioplastized rabbit iliac arteries with cutting balloon catheter.
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211
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Serpinskaya AS, Feng G, Sanes JR, Craig AM. Synapse formation by hippocampal neurons from agrin-deficient mice. Dev Biol 1999; 205:65-78. [PMID: 9882498 DOI: 10.1006/dbio.1998.9112] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Agrin, a proteoglycan secreted by motoneurons, is a critical organizer of synaptic differentiation at skeletal neuromuscular junctions. Agrin is widely expressed in the nervous system so other functions seem likely, but none have been demonstrated. To test roles for agrin in interneuronal synapse formation, we studied hippocampi from mutant mice that completely lack the z+ splice form of agrin essential for neuromuscular differentiation and also exhibit severely ( approximately 90%) reduced levels of all agrin isoforms (M. Gautam et al., 1996, Cell 85, 525-535). The brains of neonatal homozygous agrin mutants were often smaller than those of heterozygous and wild-type littermates, but were morphologically and histologically indistinguishable. In particular, antibodies to pre- and postsynaptic components of glutamatergic synapses were similarly coaggregated at synaptic sites in both mutants and controls. Because mutants die at birth due to neuromuscular defects, we cultured neurons to assess later stages of synaptic maturation. In primary cultures, the agrin-deficient neurons formed MAP2-positive dendrites and tau-1-positive axons. Synaptic vesicle proteins, AMPA- and NMDA-type glutamate receptors, GABAA receptors, and the putative synapse-organizing proteins PSD-95, GKAP, and gephyrin formed numerous clusters at synaptic sites. Quantitatively, the number of SV2-labeled contacts per neuron at day 5 and the number of PSD-95 clusters per dendrite length at day 18 in culture showed no significant differences between genotypes. Furthermore, exogenous z+ agrin was unable to induce ectopic accumulation of components of central glutamatergic or GABAergic synapses as it does for neuromuscular cholinergic synapses. These results indicate that the z+ forms of agrin are dispensable for glutamatergic and GABAergic synaptic differentiation in the central nervous system.
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212
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Sun F, Sun Z, Feng G. An adaptive fuzzy controller based on sliding mode for robot manipulators. ACTA ACUST UNITED AC 1999; 29:661-7. [DOI: 10.1109/3477.790451] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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213
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Zhang J, Feng G, Luo Y. [Analysis of chemical constituents in the essential oil from Evodia fargesii by GC/MS]. ZHONG YAO CAI = ZHONGYAOCAI = JOURNAL OF CHINESE MEDICINAL MATERIALS 1999; 22:30-1. [PMID: 12575060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
In the essential oil from Evodia fargesii Dode, 33 constituents were identified by means of GC-MS-DS. The content of these compounds are 91.0% in the essential oil of this plant. The main compounds are eighteen terpenoids.
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Liu W, Gu N, Feng G, Zhang J, Li S, Bai S, Shen T, Clair DS, He L. [Association of VNTR region of the human serotonin transporter gene with bipolar disorder among the Han Chinese]. ZHONGHUA YI XUE YI CHUAN XUE ZA ZHI = ZHONGHUA YIXUE YICHUANXUE ZAZHI = CHINESE JOURNAL OF MEDICAL GENETICS 1998; 15:345-8. [PMID: 9845763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
OBJECTIVE The serotonin transporter gene (SERT) plays an important role in the serotonin uptake into neurons. This paper reports a population and association study among the Han Chinese. METHODS DNA were extracted from peripheral blood samples of 50 patients with bipolar disorder (DSM-IIIR), 170 unrelated healthy Han Chinese individuals and 10 healthy trios for polymerase chain reaction. The VNTR locus was amplified and PCR products were separated on the 2% agrose gel. RESULTS All the three alleles(9,10 and 12 copies of repeat unit) reported in other studies were observed in this study with frequency 0.0029, 0.0676 and 0.9294, respectively. Four genotypes distributed in Caucasian: 12/12, 12/10, 12/9 and 10/10 were also found in the Han Chinese population. A significant difference in the allele frequency between the Han Chinese and Caucasian populations was found(P 0.000000001). No disequilibrium was observed after checking the Hardy-Weinberg equilibrium (P=0. 9995). The hereditary stability of this locus in accordance with the rules of Mendelian inheritance was demonstrated in the analysis of ten trios. In addition, a significant increase of frequency of the allele 10 in female patients with bipolar disorder was found (P=0. 043). CONCLUSION The data of association study might indicate a different mechanism of aetiology of bipolar disorder in male and female.
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215
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Zheng C, Feng G, Liang H. Bletilla striata as a vascular embolizing agent in interventional treatment of primary hepatic carcinoma. Chin Med J (Engl) 1998; 111:1060-3. [PMID: 11263363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
OBJECTIVE To evaluate Bletilla striata as a vascular embolizing agent in interventional treatment of primary hepatic carcinoma. METHODS We made a vascular embolizing agent from a Chinese medicinal herb, Bletilla striata (bai ji). From October 1991 to January 1995, 56 patients with primary hepatic carcinoma were treated by hepatic arterial chemoembolization with Bletilla striata angioembolus, and 50 patients with primary hepatic carcinoma who were treated by conventional gelfoam embolization served as controls. All patients were followed up for 10-48 months. RESULTS Embolization with the Bletilla striata powder produced extensive and permanent vascular obstruction, resulting in marked shrinkage of the tumor and significant decrease of serum alpha fetoprotein (AFP) level. After embolization, less collateral circulation formed later. The treatment interval was prolonged to an average of 7 months. The 1-, 2- and 3-year survival rates were 81.9%, 44.9%, and 33.6%, respectively, with a mean survival period of 19.8 months. All the clinical parameters were better than those in the control group treated by conventional gelfoam embolization. CONCLUSION Bletilla striata angioembolus is a good vascular embolizing agent for treating PHC.
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216
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Li H, Feng G, Fang Y, Li Y, Zheng J, Yi Y. [An investigation on chromosome aberration of SO-Rb50 cloned cell strains]. YAN KE XUE BAO = EYE SCIENCE 1998; 14:220-3. [PMID: 12579741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
PURPOSE To compare the differences of chromosome aberration among 3 cloning cells (MC2, MC3 and MC4) of SO-Rb50 cell line. METHOD G-banding and karyotype analysis were performed on the 11th passage cells of MC2, MC3 and MC4 cell strains. RESULTS Both numerical abnormal and structural aberrations of chromosomes could be observed in these 3 cloned cell strains. Diploid cells had the preponderance over the aneuploid cells. However, some cells showed pseudiploid karyotypes. Several kinds of structural chromosome aberrations were observed. The chromosome aberrations in the same passage of different cell strains were different. Aberration of chromosome 13 was rare and the aberration feature were different in 3 cloned cell strains. Five marker chromosomes were identified. M1, t(1;1) qterp35::q24-ter could be found in all cell strains. Other markers were seen in different cell strains respectively. In our experiment, two marker chromosome in chromosome 2, M4 and M5, were found in SO-Rb50 cell line for the first time. CONCLUSION Chromosome aberrations were different with different cloned cell strains. Combined with formerly study in SO-Rb50 cell line, we found the chromosome aberration had dynamic changes during the long-term culture in vitro. We suggest that aberration of chromosome 13 is not the only cause of Rb; aberration of chromosome 1, a common event in some neoplasias as well as in SO-Rb50, plays a meaningful role in the immortalization of this cell line; other aberrations observed in our experiment could be considered as evidences of genomic instability of the cell strains and presumably enhance the growth potential of the cells in which they develop.
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217
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Li Y, Feng G, Yi Y, Zhang P, Lin J, Chen Z. [Morphological observation of the endogenous endophthalmitis of cryptococcus neoformans]. YAN KE XUE BAO = EYE SCIENCE 1998; 14:229-31. [PMID: 12579744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
PURPOSE To observe the pathologic change of the endogenous endophthalmitis of cryptococcus neoformans. METHODS Light and electron microscope were used. RESULT The choroid was focally tumor-like by an inflammatory cells infiltrate, which consisted of multinucleated gicant, epithelioid cells and lymphocytes. Special stains (Grocott's methnamine silver, PAS, alcian blue) and electron microscope disclosed the budding form of cryptococcus neoformans. CONCLUSION The morphologic examinations are only an effectivel method of diagrosing the endogenous endophthalmitis of cryptococcus neoformans.
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Feng G, Tintrup H, Kirsch J, Nichol MC, Kuhse J, Betz H, Sanes JR. Dual requirement for gephyrin in glycine receptor clustering and molybdoenzyme activity. Science 1998; 282:1321-4. [PMID: 9812897 DOI: 10.1126/science.282.5392.1321] [Citation(s) in RCA: 321] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Glycine receptors are anchored at inhibitory chemical synapses by a cytoplasmic protein, gephyrin. Molecular cloning revealed the similarity of gephyrin to prokaryotic and invertebrate proteins essential for synthesizing a cofactor required for activity of molybdoenzymes. Gene targeting in mice showed that gephyrin is required both for synaptic clustering of glycine receptors in spinal cord and for molybdoenzyme activity in nonneural tissues. The mutant phenotype resembled that of humans with hereditary molybdenum cofactor deficiency and hyperekplexia (a failure of inhibitory neurotransmission), suggesting that gephyrin function may be impaired in both diseases.
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219
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Du D, Feng G, Liang H. [Embolotherapy of craniofacial tumors and vascular diseases: assessing the effect of different embolic agents]. LIN CHUANG ER BI YAN HOU KE ZA ZHI = JOURNAL OF CLINICAL OTORHINOLARYNGOLOGY 1998; 12:266-8. [PMID: 11189173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
To assess the effect of different embolic agents in curing craniofacial tumors and vascular diseases, 21 patients who were treated by intra-arterial embolization were divided into three groups: gelfoams, bletilla striatas and coils. The results showed that 8 cases of preoperative patients in gelfoams group had a good effect and bleeding were reduced during operation. One patient had vascular recanalization at 1 month after embolization with gelfoam. All patients in bletilla striatas had ideal effect. In coils group, collateral supplying arteries were found in 3 patients at once after embolization and the others had a good effect. In conclusion, craniofacial tumors and vascular diseases were fit to embolotherapy. The selection of embolic agents should be gelfoam in preoperative embolization and bletilla striata in palliative treatment There were not severe complications.
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Zheng J, Feng G, Li Y, Lin J, Yi Y. [The establishment, freezing-state preservation and resuscitation of retinoblastoma SO-Rb70 cell line]. YAN KE XUE BAO = EYE SCIENCE 1998; 14:80-2, 86. [PMID: 12580037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
PURPOSE To establish a new cell line of human retinoblastoma (Rb), frozen and resuscitated to provide a Rb cell reservoir for clinical and experimental research. METHODS The screening cells were washed and blown directly without centrifugation and then inoculated. Based on the cell-frozen principle, the Rb cell line was collected and established, then frozen in liquid nitrogen and resuscitated. RESULTS SO-Rb70 cell line was established successfully. 8 groups of cells were frozen. The resuscitation experiment was carried out for 6 times, 4 times being successful. CONCLUSION The preserved human Rb cells in liquid nitrogen grew normally after resuscitation with the maintenance of previous bioactivities and characteristics. This research helped to provide abundant material for further study of Rb.
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221
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Feng G, Steinbach JH, Sanes JR. Rapsyn clusters neuronal acetylcholine receptors but is inessential for formation of an interneuronal cholinergic synapse. J Neurosci 1998; 18:4166-76. [PMID: 9592096 PMCID: PMC6792822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Nicotinic acetylcholine receptors (AChRs) are clustered at high density in the postsynaptic membranes of skeletal neuromuscular junctions and cholinergic interneuronal synapses. A cytoplasmic protein, rapsyn, is essential for AChR clustering in muscle. Here, we asked whether rapsyn mediates neuronal AChR clustering at cholinergic synapses in a mammalian sympathetic ganglion, the superior cervical ganglion (SCG). Several observations supported this possibility: (1) AChR clusters containing the alpha3-5 and beta2 subunits, homologs of the muscle AChR subunits, are present at SCG synapses; (2) rapsyn RNA is readily detectable in the SCG; and (3) expression of recombinant rapsyn in heterologous cells induces aggregation of coexpressed neuronal AChR subunits. However, rapsyn protein was undetectable at ganglionic synaptic sites. Moreover, aggregates of neuronal AChRs induced in heterologous cells by full-length rapsyn remained intracellular, whereas rapsyn-induced clusters of muscle AChRs reached the cell surface. Additional studies revealed a second rapsyn RNA species in SCG generated by alternative splicing and competent to encode a novel short rapsyn isoform. However, this isoform clustered neither neuronal nor muscle AChRs in heterologous cells. Most telling, the number, size, and density of AChR clusters in SCG did not differ significantly between neonatal mice bearing a targeted mutation of the rapsyn gene and littermate controls. Thus, rapsyn is dispensable for clustering of ganglionic neuronal nicotinic AChRs.
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Sanes JR, Apel ED, Burgess RW, Emerson RB, Feng G, Gautam M, Glass D, Grady RM, Krejci E, Lichtman JW, Lu JT, Massoulié J, Miner JH, Moscoso LM, Nguyen Q, Nichol M, Noakes PG, Patton BL, Son YJ, Yancopoulos GD, Zhou H. Development of the neuromuscular junction: genetic analysis in mice. JOURNAL OF PHYSIOLOGY, PARIS 1998; 92:167-72. [PMID: 9789802 DOI: 10.1016/s0928-4257(98)80004-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Formation of the skeletal neuromuscular junction is a multi-step process that requires communication between the nerve and muscle. Studies in many laboratories have led to identification of factors that seem likely to mediate these interactions. 'Knock-out' mice have now been generated with mutations in several genes that encode candidate transsynaptic messengers and components of their effector mechanisms. Using these mice, it is possible to test hypotheses about the control of synaptogenesis. Here, we review our studies on neuromuscular development in mutant mice lacking agrin alpha CGRP, rapsyn, MuSK, dystrophin, dystrobrevin, utrophin, laminin alpha 5, laminin beta 2, collagen alpha 3 (IV), the acetylcholine receptor epsilon subunit, the collagenous tail of acetylcholinesterase, fibroblast growth factor-5, the neural cell adhesion molecule, and tenascin-C.
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Feng G, Sun G, Yang X. [Techniques in fetal rabbit surgery]. ZHONGHUA ZHENG XING SHAO SHANG WAI KE ZA ZHI = ZHONGHUA ZHENG XING SHAO SHANG WAIKF [I.E. WAIKE] ZAZHI = CHINESE JOURNAL OF PLASTIC SURGERY AND BURNS 1998; 14:186-8. [PMID: 10452062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
OBJECTIVE Experimental fetal surgery has been a popular way to study growth and development and wound healing. The rabbit continues to be a reasonable animal model. The key to success of the experiment lies in keeping the survival rate of the operated animal above 80 percent. In this paper a simple experimental method for fetus surgery in rabbits is described. METHODS Intravenous thiopental sodium is used for general anesthesia. Surgery is performed inside the uterus through hysterotomy or with the caudal part of the fetus out of the uterus. Amniotic fluid is restituted by instillation of warm saline at 37 degrees C. Special care is taken to suture the amnion. RESULTS Using these techniques carefully, we have had 90 percent of success in fetal surgery experiment. CONCLUSION A technically simple procedure has been developed for fetal rabbit surgery.
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Eberl DF, Ren D, Feng G, Lorenz LJ, Van Vactor D, Hall LM. Genetic and developmental characterization of Dmca1D, a calcium channel alpha1 subunit gene in Drosophila melanogaster. Genetics 1998; 148:1159-69. [PMID: 9539432 PMCID: PMC1460043 DOI: 10.1093/genetics/148.3.1159] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
To begin unraveling the functional significance of calcium channel diversity, we identified mutations in Dmca1D, a Drosophila calcium channel alpha1 subunit cDNA that we recently cloned. These mutations constitute the l(2)35Fa lethal locus, which we rename Dmca1D. A severe allele, Dmca1D(X10), truncates the channel after the IV-S4 transmembrane domain. These mutants die as late embryos because they lack vigorous hatching movements. In the weaker allele, Dmca1D(AR66), a cysteine in transmembrane domain I-S1 is changed to tyrosine. Dmca1D(AR66) embryos hatch but pharate adults have difficulty eclosing. Those that do eclose have difficulty in fluid-filling of the wings. These studies show that this member of the calcium channel alpha1 subunit gene family plays a nonredundant, vital role in larvae and adults.
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Zhang P, Feng G, Yi Y, Wu Z, Li Y, Zheng J. [Assessment of six drug sensitivities in established cell lines of SO-Rb50 and SO-Rb70]. [ZHONGHUA YAN KE ZA ZHI] CHINESE JOURNAL OF OPHTHALMOLOGY 1998; 34:109-12. [PMID: 11877168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
OBJECTIVE With retinoblastoma (Rb) cell lines cultured in vitro to screen chemotherapeutic drugs that are effective on Rb. METHOD Sensitivity experiments were performed with the 3, -4, 5 Dimethyliazol-2, 5 diphenyl tetrazolium bromide (MTT) assay for the drugs: dactinomycin (DACT), vincristine (VCR), VM-26, daunorubicin (DNR), DDP, bleomycin (BLMA5) against the tumor cell lines of SO-Rb50 and SO-Rb70. RESULTS The IC(50) values (microg/ml) in order at 48 hours of the above pharmaceuticals against SO-Rb50 were respectively 0.0004, 0.0016, 0.0389, 0.047, 0.29, 0.44, and those at 72 hours were 0.00025, 0.00081, 0.0151, 0.0192, 0.097, 0.11. And the IC(50) values (microg/ml) in order at 48 hours of the above pharmaceuticals against SO-Rb70 were respectively 0.00065, 0.00149, 0.0282, 0.043, 0.37, 0.215, and those at 72 hours were 0.00042, 0.00082, 0.0146, 0.0176, 0.035, 0.084. CONCLUSION The tumor cell lines of SO-Rb50 and SO-Rb70 were sensitive to the above six pharmaceuticals. By their IC(50) values, the sensitivity order to the drugs, from higher to lower, was DACT, VCR, VM-26, DNR, DDP, BLMA5.
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226
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Qian J, Feng G, Liang H. [Action of DDPH in the interventional treatment of portal hypertension induced by liver cirrhosis in rabbits]. Curr Med Sci 1998; 18:108-12. [PMID: 10806837 DOI: 10.1007/bf02888479] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/1998] [Indexed: 11/30/2022]
Abstract
To explore a new way of utilizing intervential treatment to effectively decrease the portal hypertension, the animal models of liver cirrhosis accompanying portal hypertension were set up by intraportal vein injection of suspensions of Bletilla striata to 10 rabbits by means of prospective investigational method. The catheter filled with heparin solution was remained in theportal vein for infusion of drugs. Three weeks later, DDPH solution was injected into the portal vein via the catheter to determine its effect of decreasing portal vein pressure and its influence of peripheral blood pressure and heart rate. At the same time, other 10 rabbits with liver cirrhosis associated with portal hypertension were subjected to the injection of DDPH solution via the ear vein served as control group. The results showed that administration of DDPH by portal vein could rapidly, safely and effectively decrease the portal hypertenive pressure without side effects and partially reverse liver cirrhosis, as compared with injection of DDPH via peripheral veins. It was concluded that DDPH exerted its alpha 1-adrenoceptor blocking and calcium antagonistic effects, thereby significantly reduce the portal hypertension. Injection of DDPH via portal vein is a completely new and relaible method for the treatment of liver cirrhosis with portal hypertension.
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Feng G, Zhou Y, Yang Z. [Changes of thromboxane A2 receptors and their mRNA expression and effects of their antagonist phenol red in the lung of acute lung injury of rats]. ZHONGHUA JIE HE HE HU XI ZA ZHI = ZHONGHUA JIEHE HE HUXI ZAZHI = CHINESE JOURNAL OF TUBERCULOSIS AND RESPIRATORY DISEASES 1998; 21:19-22. [PMID: 11263294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
OBJECTIVE To investigate the changes of thromboxane A2 receptors and the influence of their antagonist phenol red, and to study in molecular level the mechanism of action of thromboxane A2 in acute lung injury. METHODS Acute lung injury model of rats was produced by oleic acid, and phenol red (5 mg/kg, 50 mg/kg) was injected via vein 5 minutes before oleic acid injection. Changes of thromboxane A2 receptors and their mRNA expression in the lung were determined at 6 hours after oleic acid injection. RESULTS Down-regulation of thromboxane A2 receptors were observed, but their mRNA transcription increased significantly in the lung after oleic acid injection. The injection of phenol red before oleic acid could induce down-regulation of thromboxane A2 receptors and abolish the increase of their mRNA transcription after oleic acid injection. Phenol red could reduce LBI, RLW and improve PaO2. Histological examination of lung tissues demonstrated that the degree of lung injury had been reduced significantly. CONCLUSION Thromboxane A2 plays an important role plays in pathological processes of acute lung injury. Phenol red in vivo could effectively reduce severity of acute lung injury by blocking thromboxane A2 receptors and regulating the expression of thromboxane A2 receptors.
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Abstract
To distinguish the mass loading effect from the total frequency change is a problem in the application of a quartz crystal microbalance (QCM) biosensor in the liquid phase. Based on the characteristic damping theory, this paper proposes a new method of dual modulation to solve this problem. Using polyethyleneimine to immobilize anti-SE (staphylococcin enterotoxin) antibody (C2 type), a dual modulated QCM SE biosensor was developed and the experiment proved that it has little cross-reaction with B-type SE. The measuring curve of the sensor was also determined through experiment.
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Ettinger AJ, Feng G, Sanes JR. epsilon-Sarcoglycan, a broadly expressed homologue of the gene mutated in limb-girdle muscular dystrophy 2D. J Biol Chem 1997; 272:32534-8. [PMID: 9405466 DOI: 10.1074/jbc.272.51.32534] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The sarcoglycans are transmembrane components of the dystrophin-glycoprotein complex, which links the cytoskeleton to the extracellular matrix in adult muscle fibers. Mutations in all four known sarcoglycan genes (alpha, beta, gamma, and delta) have been found in humans with limb-girdle muscular dystrophy. We have identified a novel protein, epsilon-sarcoglycan, that shares 44% amino acid identity with alpha-sarcoglycan (adhalin). We show that epsilon-sarcoglycan is a membrane-associated glycoprotein and document its expression by Northern blotting, immunoblotting, and immunofluorescence. In contrast to alpha-delta sarcoglycans, which are expressed predominantly or exclusively in striated muscle, epsilon-sarcoglycan is broadly distributed in muscle and nonmuscle cells of both embryos and adults. These results raise the possibility that sarcoglycan-containing complexes mediate membrane-matrix interactions in many cell types.
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Zheng C, Feng G, Yang J, Liang H, Tian Z. Renal angiomyolipoma: diagnosis with B-ultrasonography, CT scanning, DSA and its interventional treatment. JOURNAL OF TONGJI MEDICAL UNIVERSITY = TONG JI YI KE DA XUE XUE BAO 1997; 16:241-4, 252. [PMID: 9389091 DOI: 10.1007/bf02888116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
From 1989, 15 cases of renal angiomyolipoma (AML) have been diagnosed by ultrasonography. CT scanning and digital subtraction angiography (DSA) at our hospital. In 8 patients with uneven hyperechoes on B-mode ultrasonography (B-US) (8/15) and 7 with low density of fat on CT scanning (7/12) accurate diagnosis was established preoperatively. DSA revealed the "berry-like" pseudoaneurysms in the arterial phase (14 cases), the defined lucent area in the nephrogram phase (10 cases) and the "onion-peel appearances" during venous phases (8 cases), correct diagnosis was achieved in all patients. 8 cases were surgically treated and 7 treated by subselective embolization of renal artery. Effects in all cases were good. The diagnostic value of B-US, CT scanning, DSA and interventional treatment of AML was discussed. It was believed that the diagnosis with DSA was a technique with high specificity, and embolization therapy was simple and effective for AML.
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Tsui HC, Feng G, Winkler ME. Negative regulation of mutS and mutH repair gene expression by the Hfq and RpoS global regulators of Escherichia coli K-12. J Bacteriol 1997; 179:7476-87. [PMID: 9393714 PMCID: PMC179700 DOI: 10.1128/jb.179.23.7476-7487.1997] [Citation(s) in RCA: 166] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The MutS, MutL, and MutH proteins play major roles in several DNA repair pathways. We previously reported that the cellular amounts of MutS and MutH decreased by as much as 10-fold in stationary-phase cultures. Consequently, we tested whether the amounts of MutS, MutL, and MutH were regulated by two global regulators, RpoS (sigma38) and Hfq (HF-I [putative RNA chaperone]), which are involved in stationary-phase transition. We report here that mutations in hfq and rpoS reversed the stationary-phase down-regulation of the amounts of MutS and MutH. hfq regulation of the amount of MutS in stationary-phase cultures was mediated by RpoS-dependent and -independent mechanisms, whereas hfq regulation of the amount of MutH was mediated only through RpoS. Consistent with this interpretation, the amount of MutS but not MutH was regulated by Hfq, but not RpoS, in exponentially growing cells. The amount of MutL remained unchanged in rpoS, hfq-1, and rpoS+, hfq+ strains in exponentially growing and stationary-phase cultures and served as a control. The beta-galactosidase activities of single-copy mutS-lacZ operon and gene fusions suggested that hfq regulates mutS posttranscriptionally in exponentially growing cultures. RNase T2 protection assays revealed increased amounts of mutS transcript that are attributed to increased mutS transcript stability in hfq-1 mutants. Lack of Hfq also increased the amounts and stabilities of transcripts initiated from P(miaA) and P1hfqHS, two of the promoters for hfq, suggesting autoregulation, but did not change the half-life of bulk mRNA. These results suggest that the amounts of MutS and MutH may be adjusted in cells subjected to different stress conditions by an RpoS-dependent mechanism. In addition, Hfq directly or indirectly regulates several genes, including mutS, hfq, and miaA, by an RpoS-independent mechanism that destabilizes transcripts.
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232
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Zhou X, Feng G, Yu B. [Serial modifications of bacon's pull through resection for low rectal cancer]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 1997; 35:716-8. [PMID: 10677988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Four modifications of Bacon's pull-thru resection were undertaken to improve postoperative defecatory control and to avoid the 2nd stage resection of the pull-thru colon stump. 54 cases of modified Bacon's rectal resection (9.64% of sphincter saving resections) were performed between 1954-1989. The 1st modification (1954) preserves the levator ani and the intact anorectal ring. The 2nd modification (1964) preserves the dentate margin and anal transitional zone (acute anal sensation), thus greatly improving defecatory control. The 3rd modification (1980) simplified intraanal resective procedure. The 4th modification (1991) was to encircle and ligate the distal end of colon over a sterilized corrugated intraluminal splinting tube (The other end of which is already connected to a long latex tube prior to operation). The latex tube was pulled out thru anus, until the colonic ligature reaches the Dentate margin, to substitute for colonic pull-thru and to divert feces during & after operation, 4-8 fine stitches approximate the colon wall 1 cm proximal to the ligature, to the cut edge of anal mucosa. The colon wall distal to the ligature sloughed in 7-10 days, the proximal colon has partially healed to the raw areas of anal canal without infection. The 2nd stage colon stump resection is thus obviated and hospitalization shortened. The postoperative anal function was good in 86.66%. Modified Bacon's operation is indicated for very low rectal cancer when the rectal remnant above levator ani after adequate resection is less than 1 cm which is difficult for intraabdominal anastomosis. It extends the scope of sphincter-saving operation. It is a good substitute for Park's coloanal anastomosis.
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Feng G, Kramann B, Zheng C, Zhou R. [Comparative study on the long-term effect of permanent embolization of hepatic artery with Bletilla striata in patients with primary liver cancer]. JOURNAL OF TONGJI MEDICAL UNIVERSITY = TONG JI YI KE DA XUE XUE BAO 1997; 16:111-6. [PMID: 9324524 DOI: 10.1007/bf02887970] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
From May, 1990 to Sept., 1993 106 cases of primary liver cancer were treated by temporary or permanent hepatic arterial embolization with Bletilla striata powders (permanent, 56 cases) or gelfoam powders (temporary, 50 cases) under controlled technical conditions, in term of degree of tumor necrosis, revascularization of tumor, and long-term effect, the results of Bletilla striata group were better as compared with those of gelfoam group. The 1, 2 and 3 year survival rates were 44.9%, 33.6% and 33.6% in Beltilla striata group while the rates were 48.9%, 31.1% and 16.0% in gelfoam group, suggesting that Bletilla striata is superior to gelfoam as an embolizing agent for hepatic carcinoma.
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Harris RS, Feng G, Ross KJ, Sidhu R, Thulin C, Longerich S, Szigety SK, Winkler ME, Rosenberg SM. Mismatch repair protein MutL becomes limiting during stationary-phase mutation. Genes Dev 1997; 11:2426-37. [PMID: 9308969 PMCID: PMC316514 DOI: 10.1101/gad.11.18.2426] [Citation(s) in RCA: 130] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/1997] [Accepted: 07/18/1997] [Indexed: 02/05/2023]
Abstract
Postsynthesis mismatch repair is an important contributor to mutation avoidance and genomic stability in bacteria, yeast, and humans. Regulation of its activity would allow organisms to regulate their ability to evolve. That mismatch repair might be down-regulated in stationary-phase Escherichia coli was suggested by the sequence spectrum of some stationary-phase ("adaptive") mutations and by the observations that MutS and MutH levels decline during stationary phase. We report that overproduction of MutL inhibits mutation in stationary phase but not during growth. MutS overproduction has no such effect, and MutL overproduction does not prevent stationary-phase decline of either MutS or MutH. These results imply that MutS and MutH decline to levels appropriate for the decreased DNA synthesis in stationary phase, whereas functional MutL is limiting for mismatch repair specifically during stationary phase. Modulation of mutation rate and genetic stability in response to environmental or developmental cues, such as stationary phase and stress, could be important in evolution, development, microbial pathogenicity, and the origins of cancer.
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235
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Li Y, Yi Y, Feng G, Chen J, Lin J. [Clinical and histological findings of retrocorneal membrane after keratoplasty]. YAN KE XUE BAO = EYE SCIENCE 1997; 13:82-4, 81. [PMID: 11189340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
PURPOSE To observe the clinicopathologic changes of retrocorneal membrane after keratoplasty. METHODS Light microscope and histochemical technique were used. RESULTS The clinicopathologic review of 108 unsuccessful keratoplasties revealed the presence of 45 retrocorneal membrane, which seems to depend on the wound abnormality, rejection of corneal transplantion, epithelium in growth, hyphema, and iris synechias. CONCLUSION The retrocorneal membrane derives from the host corneal stromal keratocytes and the metaplasia of corneal endothelial cells and monocytes.
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Dai E, Feng G, He Z, Cui D. Organic vapor sensors based on SAW resonator and organic films. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 1997; 44:309-314. [PMID: 18244128 DOI: 10.1109/58.585115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The majority of investigations of SAW devices used as chemical sensors are based on delay line oscillators. However, SAW resonator oscillator offers some advantages over the SAW delay line oscillator for its higher stability. In the incipient stage of fabricating gas sensors based upon SAW resonator, taking detection of organic vapor as an example, the analysis method that combines the SAW theory with organic film technology has been adopted to give an intensive insight into the responses of two-port SAW resonator coated with LB-film and cast-film after exposure to organic vapors.
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237
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Feng G. A new stable tracking control scheme for robotic manipulators. IEEE TRANSACTIONS ON SYSTEMS, MAN, AND CYBERNETICS. PART B, CYBERNETICS : A PUBLICATION OF THE IEEE SYSTEMS, MAN, AND CYBERNETICS SOCIETY 1997; 27:510-6. [PMID: 18255889 DOI: 10.1109/3477.584957] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The paper considers tracking control of robots in joint space. A new control algorithm is proposed based on the well known computed torque method and a compensating controller. The compensating controller is realized by using a switch type structure and an RBF neural network. It is shown that stability of the closed loop system and better tracking performance can be established based on Lyapunov theory. Simulation results are also provided to support our analysis.
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Feng G, Cao S, Rees N, Ma J. Quadratic Stabilization of Fuzzy Control Systems Using Output Feedback. JOURNAL OF INTELLIGENT & FUZZY SYSTEMS 1997. [DOI: 10.3233/ifs-1997-5304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Li Y, Feng G, Yi Y, Lin J, Zheng G, Zhang J. [Observation of the invasion of retinoblastoma cells to ocular tissues in vitro]. YAN KE XUE BAO = EYE SCIENCE 1996; 12:173-7. [PMID: 15508248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
PURPOSE To study the invasion of retinoblastoma cells to ocular tissues. METHODS The SO-Rb50 cells of retinoblastoma and various ocular tissue cells were co-cultured. The morphological change of the SO-Rb50 cells adherent to ocular tissue cells was observed. RESULTS SO-Rb50 cells can adhere to the various ocular tissues. The adherent ability of SO-Rb50 cell to different ocular tissue cells was different. Tumor cells could be adhesive to keratocyte, scleral fibrocyte, the fibrocyte and the melanocyte of iris and choroid, the epithelial cells of lens, and the astrocyte of optic nerve and grow, but can not be adhesive to the corneal epithelial cell and retinal pigment epithelial cell. CONCLUSIONS We consider that the interactions of tumor cells with host cells, as with extracellular matrix, also play an important role in the selective growth of organ and tissue of tumor cell metastasis. Retinoblastoma cells can not adhere to retinal pigment epithelial cell, which may serve as a barrier to obstruct the invasion of tumor cell to the choroid. Being adherent to the glial cells of optic nerve, tumor cells grow in flat and the shape of tumor cell changes, which may be the cause of tumor cell migrate rapidly and grow in the brain while the optic nerve was invaded by tumor cells.
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Li Y, Feng G, Yi Y. [Observation of the invasion of retinoblastoma cells to the corneal epithelial cells and keratocytes in culture]. [ZHONGHUA YAN KE ZA ZHI] CHINESE JOURNAL OF OPHTHALMOLOGY 1996; 32:417-20. [PMID: 9590806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To study the invasive ability of retinoblastoma cells into the corneal epithelial cells and keratocytes in culture. METHODS SO-Rb50 cells of retinoblastoma, corneal epithelial cells and keratocytes were co-cultured. The morphological changes of SO-Rb50 cells adherent to the corneal epithelial cells and keratocytes were observed. The distribution of proteoglycans in the SO-Rb50 cells, corneal cells and keratocytes was analyzed by histochemical method and electron microscopy. RESULTS SO-Rb50 cells could adhere to the keratocytes, but did not adhere to the corneal epithelial cells. There are common hyaluronidase-resistant and chondroitinase-resistant proteoglycans on the surface of SO-Rb50 cells and corneal epithelial cells. Chondroitin is present on the surface of keratocytes. CONCLUSION It is considered that the cell surface proteoglycans may play an important role in mediating SO-Rb50 tumor cell adhesion and non-adhesion to normal cells.
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Tsui HC, Feng G, Winkler ME. Transcription of the mutL repair, miaA tRNA modification, hfq pleiotropic regulator, and hflA region protease genes of Escherichia coli K-12 from clustered Esigma32-specific promoters during heat shock. J Bacteriol 1996; 178:5719-31. [PMID: 8824618 PMCID: PMC178412 DOI: 10.1128/jb.178.19.5719-5731.1996] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The amiB-mutL-miaA-hfq-hflX-hflK-hflC superoperon of Escherichia coli contains genes that are important for diverse cellular functions, including DNA mismatch repair (mutL), tRNA modification (miaA), pleiotropic regulation (hfq), and proteolysis (hflX-hflK-hflC). We show that this superoperon contains three E simga(32)-dependent heat shock promoters, P(mutL)HS,P(miaA)HS, and P1(hfq)HS, in addition to four E sigma(70)-dependent promoters, P(mutL), P(miaA), P2(hfq), and P3(hfq). Transcripts from P(mutL)HS and P(miaA)HS were most prominent in vivo during extreme heat shock (50 degrees C), whereas P1(hfq)HS transcripts were detectable under nonshock conditions and increased significantly after heat shock at 50 degrees C. The P(mutL)HS, P(miaA)HS, and P1(hfq)HS transcripts were not detected in an rpoH null mutant. All three promoters were transcribed by E sigma (32) in vitro at 37 degrees C and contain -35 and -10 regions that resemble the E sigma(32) consensus. In experiments to assess the possible physiological relevance of the P(mutL)HS and P(miaA)HS promoters, we found that E. coli prototrophic strain MG 1655 increased in cell mass and remained nearly 100% viable for several hours at 50 degrees C in enriched media. In these cells, a significant fraction of mutL and hfq-hflA region transcripts were from P(mutL)HS and P1(hfq)HS, respectively, and the amounts of the miaA, hfq, hflX, hflK, and hflC transcripts increased in comparison with those in nonstressed cells. The cellular amounts of MutL and the hfq gene product (HF-I protein) were maintained during heat shock at 44 or 50 degrees C. Consistent with their expression patterns, miaA and hfq were essential for growth and viability, respectively, at temperatures of 45 degrees C and above. Together, these results suggest that there is a class of E sigma(32) promoters that functions mainly at high temperatures to ensure E. coli function and survival.
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Zhang-Sun G, Yang C, Viallet J, Feng G, Bergeron JJ, Posner BI. A 60-kilodalton protein in rat hepatoma cells overexpressing insulin receptor was tyrosine phosphorylated and associated with Syp, phophatidylinositol 3-kinase, and Grb2 in an insulin-dependent manner. Endocrinology 1996; 137:2649-58. [PMID: 8770882 DOI: 10.1210/endo.137.7.8770882] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Tyrosine phosphorylation of cellular proteins is an early and key step after activation of the insulin receptor kinase (IRK). The study of the properties of these proteins should contribute to our understanding of insulin action. In rat hepatoma cells overexpressing human insulin receptors (HTC-IR), insulin treatment resulted in rapid tyrosine phosphorylation of proteins of 180, 94, 68, and 60 kDa. When lysates from insulin-treated cells were immunoprecipitated with anti-Syp antibody, subsequent immunoblotting identified p65 and p68, which reacted with anti-Syp, and p6O and p68, which reacted with antiphosphotyrosine antibody. Thus, insulin treatment yielded tyrosine phosphorylation of both Syp and a Syp-associated p6O molecule. When lysates from insulin-treated cells were adsorbed with a glutathione S-transferase (GST)-Syp-Src homology-2 (SH2) fusion protein, tyrosine- phosphorylated p6O was sequestered. After subjecting lysates to SDS-PAGE, the GST-SypSH2 fusion protein was found to bind to p18O, p94, and p6O. Thus, Syp associates directly with a 60-kDa IRK substrate via its SH2 domains. Syp-associated p6O differed from the 60- to 62-kDa proteins, associating with ras guanosine triphosphatase-activating protein, which also underwent modest tyrosine phosphorylation in response to insulin. Preadsorption of cell lystates with antibody against the 85-kDa subunit (p85) of phosphatidylinositol 3-kinase substantially reduced the amount of p60 subsequently immunoprecipitated by anti-Syp. Thus, p60 associates with both Syp and p85. The amount of tyrosine-phosphorylated p60 exceeded that of p180 in anti-Syp immunoprecipitates, whereas their proportion was comparable in anti-p85 immunoprecipitates. Grb2 was also observed in the anti-Syp immunoprecipitates. When lysates from insulin-treated cells were adsorbed with GST-p85SH2 domains or GST-Grb2, the subsequent eluates contained tyrosine-phosphorylated p60, as determined by immunoblotting with antiphosphotyrosine. Membrane binding assays using GST fusion proteins showed that these associations were direct. Studies in rat liver, muscle, and adipose tissue identified insulin-dependent association of Syp, Grb2, and p85 with tyrosine-phosphorylated p60 in adipose tissue only. We conclude that insulin treatment of HTC-IR cells and rat adipose tissue results in the tyrosine phosphorylation of p60, which might participate in the recruitment of downstream effectors involved in insulin signal transduction.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Adipose Tissue/metabolism
- Animals
- Blotting, Western
- Electrophoresis, Polyacrylamide Gel
- ErbB Receptors/metabolism
- Female
- GRB2 Adaptor Protein
- Glutathione Transferase/biosynthesis
- Humans
- Insulin/pharmacology
- Intracellular Signaling Peptides and Proteins
- Kinetics
- Liver/metabolism
- Liver Neoplasms, Experimental
- Male
- Molecular Weight
- Muscle, Skeletal/metabolism
- Organ Specificity
- Phosphatidylinositol 3-Kinases
- Phosphoproteins/analysis
- Phosphoproteins/metabolism
- Phosphotransferases (Alcohol Group Acceptor)/metabolism
- Phosphotyrosine/metabolism
- Protein Tyrosine Phosphatase, Non-Receptor Type 11
- Protein Tyrosine Phosphatase, Non-Receptor Type 6
- Protein Tyrosine Phosphatases/analysis
- Protein Tyrosine Phosphatases/metabolism
- Proteins/analysis
- Proteins/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptor, Insulin/biosynthesis
- Receptor, Insulin/metabolism
- Receptor, Insulin/physiology
- Recombinant Fusion Proteins/biosynthesis
- Transfection
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243
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Zheng C, Feng G, Zhou R. [New use of Bletilla striata as embolizing agent in the intervention treatment of hepatic carcinoma]. ZHONGHUA ZHONG LIU ZA ZHI [CHINESE JOURNAL OF ONCOLOGY] 1996; 18:305-7. [PMID: 9387329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A Chinese herb, Bletilla striata, was used as embolizing agent in order to improve the therapeutic results of intervention treatment of liver cancer. From October 1991 to January 1995, 56 cases of hepatic carcinoma were treated with Bletilla striata by hepatic artery embolization, with conventional gelform embolization in 50 cases as control. Patients were followed-up for 10-48 months. Embolization with Bletilla striata led to extensive and permanent vascular obstruction, accompanied with marked shrinkage of tumor size and significant decrease in serum AFP levels. Collaterals were few in number and collateral circulation was established late so that the treatment intervals could be prolonged, with an average of 7 months. The 1-, 2-, and 3-year survival rate was 81.9%, 44.9% and 33.6%, respectively, with a median survival time of 19.8 months. All the clinical parameters were better than those treated with conventional gelform embolization. The results indicate that Bletilla striata is an ideal vascular embolizing agent.
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244
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Feng G, Hannan F, Reale V, Hon YY, Kousky CT, Evans PD, Hall LM. Cloning and functional characterization of a novel dopamine receptor from Drosophila melanogaster. J Neurosci 1996; 16:3925-33. [PMID: 8656286 PMCID: PMC6578617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1995] [Revised: 03/26/1996] [Accepted: 04/02/1996] [Indexed: 02/01/2023] Open
Abstract
A cDNA clone is described that encodes a novel G-protein-coupled dopamine receptor (DopR99B) expressed in Drosophila heads. The DopR99B receptor maps to 99B3-5, close to the position of the octopamine/tyramine receptor gene at 99A10-B1, suggesting that the two may be related through a gene duplication. Agonist stimulation of DopR99B receptors expressed in Xenopus oocytes increased intracellular Ca2+ levels monitored as changes in an endogenous inward Ca2+-dependent chloride current. In addition to initiating this intracellular Ca2+ signal, stimulation of DopR99B increased cAMP levels. The rank order of potency of agonists in stimulating the chloride current is: dopamine > norepinephrine > epinephrine > tyramine. Octopamine and 5-hydroxytryptamine are not active (< 100 microM). This pharmacological profile plus the second-messenger coupling pattern suggest that the DopR99B receptor is a D1-like dopamine receptor. However, the hydrophobic core region of the DopR99B receptor shows almost equal amino acid sequence identity (40-48%) with vertebrate serotonergic, alpha 1- and beta-adrenergic, and D1-like and D2-like dopaminergic receptors. Thus, this Drosophila receptor defines a novel structural class of dopamine receptors. Because DopR99B is the second dopamine receptor cloned from Drosophila, this work establishes dopamine receptor diversity in a system amenable to genetic dissection.
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245
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Heisler LM, Feng G, Jin DJ, Gross CA, Landick R. Amino acid substitutions in the two largest subunits of Escherichia coli RNA polymerase that suppress a defective Rho termination factor affect different parts of the transcription complex. J Biol Chem 1996; 271:14572-83. [PMID: 8662850 DOI: 10.1074/jbc.271.24.14572] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Among the earliest rpoBC mutations identified are three suppressors of the conditional lethal rho allele, rho201. These three mutations are of particular interest because, unlike rpoB8, they do not increase termination at all rho-dependent and rho-independent terminators. rpoB211 and rpoB212 both change Asn-1072 to His in conserved region H of rpoB (betaN1072H), whereas rpoC214 changes Arg-352 to Cys in conserved region C of rpoC (beta'R352C). Both substitutions significantly reduce the overall rate of transcript elongation in vitro relative to wild-type RNA polymerase; however, they probably slow elongation for different reasons. The nucleotide triphosphate concentrations required at the T7 A1 promoter for both abortive trinucleotide synthesis and for promoter escape are much greater for betaN1072H. In contrast, beta'R352C and two adjacent substitutions (beta'G351S and beta'S350F), but not betaN1072H, formed open complexes of greatly reduced stability. The sequence in this region of beta' modestly resembles a region of Escherichia coli DNA polymerase I that contacts the phosphate backbone of DNA in co-crystals. Core determinants affecting open complex formation do not reside exclusively in beta', however, since the Rifr mutation rpoB2 in beta also dramatically destabilized open complexes. We suggest that the principal defects of the two Rho-suppressing substitutions may differ, perhaps reflecting a greater role of beta region H in nucleoside triphosphate-binding and nucleotide addition and of beta' region C in contacts to the DNA strands that could be important for translocation. Although both probably suppress rho201 by slowing RNA chain elongation, these differences may lead to terminator specificity that depends on the rate-limiting step at different sites.
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246
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Feng G, Castelli E. Some acoustic features of nasal and nasalized vowels: a target for vowel nasalization. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 1996; 99:3694-3706. [PMID: 8655801 DOI: 10.1121/1.414967] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In order to characterize acoustic properties of nasal and nasalized vowels, these sounds will be considered as a dynamic trend from an oral configuration toward an [n]-like configuration. The latter can be viewed as a target for vowel nasalization. This target corresponds to the pharyngonasal tract and it can be modeled, with some simplifications, by a single tract without any parallel paths. Thus the first two resonance frequencies (at about 300 and 1000 Hz) characterize this target well. A series of measurements has been carried out in order to describe the acoustic characteristics of the target. Measured transfer functions confirm the resonator nature of the low-frequency peak. The introduction of such a target allows the conception of the nasal vowels as a trend beginning with a simple configuration, which is terminated in the same manner, so allowing the complex nasal phenomena to be bounded. A complete study of pole-zero evolutions for the nasalization of the 11 French vowels is presented. It allows the proposition of a common strategy for the nasalization of all vowels, so a true nasal vowel can be placed in this nasalization frame. The measured transfer functions for several French nasal vowels are also given.
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247
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Ping Z, Feng G, Yi Y, Wu Z, Li Y, Zheng J. [Assessment of the toxicity of TAH on the cell lines of SO-Rb50 and SO-Rb70]. YAN KE XUE BAO = EYE SCIENCE 1996; 12:83-7. [PMID: 9639853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE MTT assay was evaluated on cytoxicity for suspension growing cell lines of SO-Rb50 and SO-Rb70, and the toxicity of TAH (the total alkaloid of peqanum harmala L) on the above cell lines was assessed. METHODS The relationships between cell number and optical density, between optical density and exposure time of MTT, and the stability of formazan crystal solution in MDSO were determined. And the toxicity of TAH on the cell lines of SO-Rb50 and SO-Rb70 in vitro with MTT assay was assessed. RESULTS There was a direct proportional relationship between the amount of cell number and its optical density; The optical density increased gradully within 12 hours of the MTT incubation time; The stable time of the formazan crystal solved in DMSO was 11 hours. The IC50 values (micrograms/ml) of TAH on SO-Rb50 were 10.66, 4.82 respectively for 48 and 72 hours; and on SO-Rb70 were 6.38, 4.2 respectively for 48 and 72 hours. CONCLUSION MTT assay can be used for suspension growing cell lines of SO-Rb50 and SO-Rb70: TAH has obvious toxicity to these two cell lines.
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248
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Zheng J, Feng G, Li Y, Yi Y. [The approach of cloned method in a human retinoblastoma cell line SO-Rb50]. YAN KE XUE BAO = EYE SCIENCE 1996; 12:79-82. [PMID: 9639852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE In order to obtain the same characteristic tumor cells in genetical and biological aspect, the cloned human retinoblastoma cell line SO-Rb50 established in our department is reported in this paper. METHOD SO-Rb50 cells were cloned in multi-well plates. RESULT Non-rosette Rb cells were successfully cloned while rosette Rb cells failed. CONCLUSION The result suggested that high differentiated Rb cells were difficult to be cloned.
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249
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Feng G, Tsui HC, Winkler ME. Depletion of the cellular amounts of the MutS and MutH methyl-directed mismatch repair proteins in stationary-phase Escherichia coli K-12 cells. J Bacteriol 1996; 178:2388-96. [PMID: 8636043 PMCID: PMC177950 DOI: 10.1128/jb.178.8.2388-2396.1996] [Citation(s) in RCA: 138] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The MutL, MutS, and MutH proteins mediate methyl-directed mismatch (MDM) repair and help to maintain chromosome stability in Escherichia coli. We determined the amounts of the MDM repair proteins in exponentially growing, stationary-phase, and nutrient-starved bacteria by quantitative Western immunoblotting. Extracts of null mutants containing various amounts of purified MDM repair proteins were used as quantitation standards. In bacteria growing exponentially in enriched minimal salts-glucose medium, about 113 MutL dimers, 186 MutS dimers, and 135 MutH monomers were present per cell. Calculations with the in vitro dissociation constants of MutS binding to different mismatches suggested that MutS is not present in excess, and may be nearly limiting in some cases, for MDM repair in exponentially growing cells. Remarkably, when bacteria entered late stationary phase or were deprived of a utilizable carbon source for several days, the cellular amount of MutS dropped at least 10-fold and became barely detectable by the methods used. In contrast, the amount of MutH dropped only about threefold and the amount of MutL remained essentially constant in late-stationary-phase and carbon-starved cells compared with those in exponentially growing bacteria. RNase T2 protection assays showed that the amounts of mutS, mutH, and mutL, but not miaA, transcripts decreased to undetectable levels in late-stationary-phase cells. These results suggested that depletion of MutS in nutritionally stressed cells was possibly caused by the relative instability of MutS compared with MutL and MutH. Our findings suggest that the MDM repair capacity is repressed in nutritionally stressed bacteria and correlate with conclusions from recent studies of adaptive mutagenesis. On the other hand, we did not detect induction of MutS or MutL in cells containing stable mismatches in multicopy single-stranded DNA encoded by bacterial retrons.
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250
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Cao SG, Rees NW, Feng G. Stability analysis of fuzzy control systems. IEEE TRANSACTIONS ON SYSTEMS, MAN, AND CYBERNETICS. PART B, CYBERNETICS : A PUBLICATION OF THE IEEE SYSTEMS, MAN, AND CYBERNETICS SOCIETY 1996; 26:201-4. [PMID: 18263023 DOI: 10.1109/3477.484455] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A discrete-time fuzzy control system which is composed of a dynamic fuzzy model and a fuzzy state feedback controller is proposed. Stability of the fuzzy control system is discussed and a sufficient condition to guarantee the stability of the system is given in terms of uncertain linear system theory. The results in this paper improve our previous stability results. An example is used to show the proposed method.
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