2351
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Chen G, Wu Y, Xu X. [Mechanism of changes in coagulation after electric burns in rabbits]. 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 1994; 10:462-5. [PMID: 7720008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The changes in local lesion after high-voltage electric burns ares dependent on many factors. One of the important factors is the change in coagulation. In this paper, a high-voltage electrical burn model was reproduced in rabbits for the purpose of investigating the coagulation mechanism. It was found that AT-III and PC showed elevation and declination, respectively, at 6h and 12h postburn. PAI:A and t-PA:A also showed obvious changes, while FDP showed continuous elevation at 6h up to 5d postburn. The findings probable provided the explanation of the occurrence of thrombosis at 6h to 12h postburn, and the second episode of thrombosis on the 5th day.
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2352
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Luo J, Qi K, Chen G. [Anatomy of the eyebrow and upper eyelid region and its significance in ptosis 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 1994; 10:466-9. [PMID: 7720009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The article reports the results of the anatomic observations from dissecting 30 upper eyelids and 8 eyebrows of adult cadavers. In the eyebrow region, the anterior and posterior sheaths of the galea enclose the muscle plane where the frontalis, orbicularis and corrugator muscles are interdigitated. The posterior sheath attaches to supraorbital ridge through the brow fat pad. It was found that a few fibers of the frontalis muscle insert to the skin of the brow. In the upper eyelid, the orbital septum fuses with the aponeurosis at or just below the upper margin of the tarsus. The levator aponeurosis, Muller's muscle, particularly their attachments were carefully observed and measured. Finally, the application of the anatomy in the ptosis surgery is discussed.
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2353
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Mukamel S, Takahashi A, Wang HX, Chen G. Electronic Coherence and Nonlinear Susceptibilities of Conjugated Polyenes. Science 1994; 266:250-4. [PMID: 17771444 DOI: 10.1126/science.266.5183.250] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
A dynamic theory that connects electronic motions and the nonlinear optical response of conjugated polyenes is developed by introducing the concept of electronic normal modes. A useful picture for the mechanism of optical nonlinearities is obtained by identifying the few dominant modes. This quasi-particle electron-hole representation establishes a close analogy with small semiconductor particles (quantum dots) and is very different from the traditional approach based on electronic eigenstates. The effective conjugation length (coherence size), which controls the scaling and saturation of the static third-order susceptibility X((3)) with the number of double bonds, is related to the coherence of the relative motion of electron-hole pairs created upon optical excitation.
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2354
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Chen G, Müller M, Potrykus I, Hohn T, Fütterer J. Rice tungro bacilliform virus: transcription and translation in protoplasts. Virology 1994; 204:91-100. [PMID: 8091688 DOI: 10.1006/viro.1994.1513] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Protoplasts from cell suspension cultures of Oryza sativa (monocot) and Orychophragmus violaceus (dicot) support transcription from the rice tungro bacilliform virus (RTBV) promoter and translation of the resulting mRNA despite the presence of a long leader sequence with strong secondary structure and 12 short open reading frames. Transcriptional elements located both upstream and downstream of the transcription initiation site are defined by deletion analysis and the functional TATA motif is determined. Expression of an open reading frame downstream of the entire leader is more efficient than that downstream of truncated derivatives. For optimal expression sequences in the 5' and 3' parts of the leader are required.
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2355
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Gao X, Perchellet E, Chen G, Newell S, Perchellet J. Characterization of the tumor-promoting activity of thapsigargin in cf-1 mouse skin. Int J Oncol 1994; 5:793-803. [PMID: 21559644 DOI: 10.3892/ijo.5.4.793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The ornithine decarboxylase (ODC), hydroperoxide (HPx) and DNA responses to 12-O-tetradecanoylphorbol-13-acetate (TPA) and mezerein (MEZ) are similar in vivo. Thapsigargin (TG) respectively mimics about 15, 75 and 75% of the ODC, HPx and DNA responses to TPA and these differences persist after chronic treatments. The peak of ODC induction 5 h after 2 TG treatments at 12 to 48-h intervals is twice that produced 16 h after a single TG treatment or 5 h after 2 TG treatments at a 72-h interval. The ODC-inducing activity of TG is dose dependent from 1 to 15 nmol and its magnitude is maximal after 2 applications. The biochemical effects of TG and TPA are neither synergistic nor additive. But the ODC response to TG is greater when this compound is applied 48 h after TPA than after another TG treatment. In initiated skins promoted 2x/week with 5 nmol of TPA, MEZ, or TG, the Ist papillomas (PAs) appear at 7, 12 and 17 weeks, the tumor incidences are 100, 40 and 24%, and there are 17, 1 and 0.6 PAs/mouse, respectively. The tumor-promoting activity of TG is increased at a higher dose (15 nmol), slightly accelerated at a higher frequency (1x/2 days) and decreased at a lower frequency (1x/week). TPA applied 1x/3 weeks is insufficient to promote tumors but slightly enhances the tumor-promoting activity of TG. MEZ applied 1x/4 weeks in stage 2 also accelerates the tumor-promoting activity of TG. TG is effective as a stage 1 promoter but its promoting activity is not enhanced by stage 1 treatments with TPA. In contrast to TPA or even MEZ, TG may be a very weak tumor promoter because it is a very weak ODC inducer and mobilizes enough intracellular free Ca2+ to impair tumor cell proliferation.
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2356
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Chen G, Klimeck G, Datta S, Goddard WA. Resonant tunneling through quantum-dot arrays. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:8035-8038. [PMID: 9974804 DOI: 10.1103/physrevb.50.8035] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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2357
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Chen G, Birnbaum RS, Yablonka-Reuveni Z, Quinn LS. Separation of mouse crushed muscle extract into distinct mitogenic activities by heparin affinity chromatography. J Cell Physiol 1994; 160:563-72. [PMID: 8077294 DOI: 10.1002/jcp.1041600320] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Extracts from gently crushed adult mouse skeletal muscles (CMEs) contain potent myoblast mitogens, and may be used as a model system to investigate myotrophic factors released by adult muscles following injury. CME was separated into four peaks of mitogenic activity by heparin affinity chromatography. The fraction of CME that did not bind to heparin contained transferrin (Tf). Three peaks of mitogenic activity were eluted from the heparin-agarose columns at NaCl concentrations of 0.4 M, 0.9 M, and 2.0 M. A 46 kDa protein that shared antigenicity with the BB isoform of platelet-derived growth factor (PDGF-BB) was present in the 0.4 M NaCl eluant. Mitogenic activity in the 2.0 M NaCl peak eluted identically to purified basic fibroblast growth factor (bFGF), did not act additively to saturating amounts of purified bFGF, and was neutralized by anti-bFGF antibodies. The 0.9 M NaCl eluant acted additively to the combination of three known growth factors for myoblasts, bFGF, insulin-like growth factor 1, and epidermal growth factor, to stimulate C2 myoblast proliferation, suggesting this fraction contains a mitogenic activity which does not utilize (and hence compete for) receptors for the known mitogens for myoblasts. Additionally, the 0.9 M NaCl eluant did not stimulate proliferation of fibroblast-like cells derived from muscle tissue. The unbound, 0.4 M NaCl, 0.9 M NaCl, and 2.0 M NaCl eluants from the heparin-agarose column acted additively to one another to stimulate myoblast proliferation. Our data suggest that Tf, PDGF-BB-like molecules, bFGF-like activity, and an uncharacterized heparin-binding myoblast mitogen could be released after muscle injury and act to stimulate satellite cell proliferation.
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2358
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Lu JF, Chen G, Xiang BR, An DK. Pharmacokinetic-pharmacodynamic modeling of electroencephalographic effects of midazolam in eight Chinese men. ZHONGGUO YAO LI XUE BAO = ACTA PHARMACOLOGICA SINICA 1994; 15:399-403. [PMID: 7717060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The effects of midazolam (Mid) on the electroencephalogram (EEG) were related to Mid concentrations in serum in 8 Chinese healthy male volunteers for the assessment of concentration-effect relationship. The total number of waves per second within the frequency range of 12-30 Hz (TNW12-30) in the central-occipital (C1-O1) lead EEG obtained by aperiodic analysis was used as EEG effect of the drug. The PK-PD parameters were calculated by PK-PD software using the sigmoid Emax model. They were: T1(2)keo = 1.3 +/- 0.9 min-1, EC50 = 254 +/- 54 micrograms.L-1, N = 2.9 +/- 0.6. E0 and Emax were calculated from the observed values, being 3.4 +/- 1.3 and 11.4 +/- 2.2 TNW12-30, respectively. Our results showed that the concentration-EEG effect relationship of Mid could be characterized in individual Chinese man using TNW12-30 as a measure of pharmacological response.
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2359
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Chen G, Lin W, Feng X. Relationship between serum apolipoprotein levels and coronary heart disease in the Hainanese province of China. Atherosclerosis 1994. [DOI: 10.1016/0021-9150(94)93578-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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2360
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Yao Z, Feng X, Chen G. Serum lipids, lipoproteins and apolipoproteins in diabetes. Atherosclerosis 1994. [DOI: 10.1016/0021-9150(94)93997-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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2361
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Chen G, Wang SH, Converse CA. Glutathione increases interleukin-2 production in human lymphocytes. INTERNATIONAL JOURNAL OF IMMUNOPHARMACOLOGY 1994; 16:755-60. [PMID: 7806433 DOI: 10.1016/0192-0561(94)90095-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
It is known that glutathione (GSH) has an immunological effect on several features of the immune system. The present study investigated the effects of GSH on interleukin-2 (IL-2) production from normal human peripheral blood lymphocytes (PBL). The results showed that both exogenous GSH and 2-mercaptoethanol (2-ME) significantly increased intracellular GSH levels after PBL were incubated with both agents. IL-2 production from PBL was markedly increased at the presence of exogenous GSH (0.5-8 mmol/l) or 2-ME (12.5-50 mumol/l) which corresponded to 1.57-2.82 nmol/10(6) cells and 1.41 - 1.80 nmol/10(6) cells of intracellular concentrations of GSH, respectively. However, IL-2 production seemed to reach a steady level when exogenous GSH concentrations in cell culture were between 2 and 8 mmol/l. The findings also showed that there was a positive correlation between the IL-2 concentrations and intracellular GSH levels. This study indicated that both exogenous GSH and 2-ME were able to elevate intracellular GSH levels and the increased intracellular GSH could increase IL-2 production in vitro. It is suggested that GSH may exert its effects on the immune system via the regulation of IL-2 synthesis.
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2362
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Chen G, Wilson R, Boyd P, Mckillop JH, Leitch C, Walker JJ, Burdon RH. Normal superoxide dismutase (SOD) gene in pregnancy-induced hypertension: is the decreased SOD activity a secondary phenomenon? Free Radic Res 1994; 21:59-66. [PMID: 7921164 DOI: 10.3109/10715769409056557] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Reactive oxygen species (ROS) have been implicated in the pathogenesis of pregnancy-induced hypertension (PIH). A genetic factor is also thought to be associated with the disease. The aim of the present study was to investigate whether decreased superoxide dismutase (SOD) activity in PIH resulted from gene abnormalities. Fourteen patients with PIH were enrolled in the study. Normal pregnant women and normal nonpregnant women served as controls. Genomic DNA and mRNA were isolated from white cells and subjected to Southern and Northern blot analysis with a 600 bp CuZn-SOD probe. SOD activity was also determined in the white blood cells and red blood cells. The results showed that SOD activity was significantly reduced in patients with PIH compared to both control groups. There were no significant differences in the size of the CuZn-SOD gene and its expression between the patients with PIH and the controls. This study confirmed that there was a decreased SOD activity in PIH but revealed neither major structural changes in the genomic DNA nor mRNA size of CuZn-SOD. Our results suggest that the decreased SOD levels in PIH are not due to abnormalities in the CuZn-SOD gene and are an acquired phenomenon which occurs during the development of the disease.
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2363
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Chen G, Wilson R, McKillop JH, Walker JJ. The role of cytokines in the production of prostacyclin and thromboxane in human mononuclear cells. Immunol Invest 1994; 23:269-79. [PMID: 7959961 DOI: 10.3109/08820139409066823] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The aim of the present work was to study the regulatory effects of cytokines (TNF alpha, IL-1 beta and IL-2) on the production of the prostglandins (PGI2 and TXA2) from human mononuclear cells. Our major findings were: (1) TNF alpha, IL-1 beta and IL-2 were all able to induce PGI2 and TXA2 syntheses in mononuclear cells. (2) TNF alpha exerted a biphasic effect on prostaglandin production. The lower concentrations of TNF alpha enhanced prostaglandin synthesis while the higher concentrations did not. (3) TNF alpha had a positive effect after only a 30-minute incubation, whereas IL-1 beta and IL-2 required a 8-hour incubation to produce a significant effect. This suggests that the different mechanisms are involved in their actions. (4) The effects of cytokines on the production of PGI2 were greater than that on the production of TXA2. It is concluded that cytokines can not only regulate the production of prostaglandins but also change the pattern of their formation.
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2364
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Klimeck G, Chen G, Datta S. Conductance spectroscopy in coupled quantum dots. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:2316-2324. [PMID: 9976449 DOI: 10.1103/physrevb.50.2316] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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2365
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Xu W, Chen G, Peterson J. The blue up-conversion emission of glass ceramics doped with Er3+ ion upon green line (19436 cm−1) excitation. Chem Phys Lett 1994. [DOI: 10.1016/0009-2614(94)00531-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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2366
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Chen G, Zeller WJ. Increased poly(ADP-ribose) formation in cisplatin-resistant rat ovarian tumor cells. Anticancer Res 1994; 14:1461-7. [PMID: 7979172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Poly(ADP-ribose) polymerase (PARP) is well known for its involvement in DNA repair, although the underlying mechanisms remain unclear. Poly(ADP-ribose) is synthesized on nuclear proteins in response to DNA damage and consequently implicated in the toxicity of various xenobiotics, including anticancer agents. The metabolism of poly(ADP-ribose) in cisplatin (DDP)-sensitive (O342) and -resistant (O-342/DDP) rat ovarian tumor cells was investigated to explore its possible roles in DDP resistance. The poly(ADP-ribose) synthesis assayed as [3H]-NAD incorporation was higher by up to two-fold in the resistant O-342/DDP cells, when compared with that of its DDP-sensitive subline O-342. Furthermore, this difference still existed even in the presence of saturating concentrations of a double-stranded octameric deoxynucleotide that stimulates the enzyme directly, indicating a higher maximal poly(ADP-ribosyl)ation capacity of the resistant cells. In addition, acute treatment of O-342 cells with DDP also stimulated the polymer synthesis by up to 1.6-fold, which was totally suppressed by inclusion of 2.5 mM 3AB in the post-exposure incubation. Western blot analysis, however, failed to reveal higher levels of the enzyme proteins in the resistant cells. A higher level of endogenous DNA single strand breaks was also detected in both intact and permeabilized cells of O-342/DDP line. Taken together, these results demonstrate that the DDP resistance phenotype in these rat ovarian tumor cells is accompanied by a higher cellular poly(ADP-ribosyl)ation capacity, which may be linked with DDP resistance by enhancing the repair of DDP-inflicted DNA damage.
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2367
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Chen G, Janzen EG, Bray TM. Identification of 3-MI-derived N-centered radicals obtained from incubation of 3-MI with microsomal-NADPH system by EPR-HPLC spin trapping. Free Radic Biol Med 1994; 17:19-25. [PMID: 7959163 DOI: 10.1016/0891-5849(94)90004-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
3-Methylindole (3-MI) is a metabolite of tryptophan that causes acute pulmonary edema and emphysema in ruminants when administered orally or intravenously. Electron paramagnetic resonance (EPR) spin-trapping techniques have been used to investigate the in vitro and in vivo formation of free radicals during 3-MI metabolism by goat lung. Utilizing C-phenyl-N-tert-butyl nitrone (PBN), a nitrogen-centered free radical has been detected from 3-MI in goat lung microsomal incubation. The EPR spectrum of the spin adduct is identical to that observed when 3-MI is irradiated with ultraviolet light. The formation of a nitrogen-centered 3-MI free radical is followed by the appearance of a carbon-centered radical in microsomal preparations. The objective of the present study is to prove that the nitrogen-centered radical generated from the 3-MI incubation system is a 3-MI radical utilizing [14C]-3 MI and the EPR-HPLC technique. The HPLC chromatogram includes three peaks that give EPR signals. These peaks are assigned to nitrogen-, oxygen- and carbon-centered radical adducts. The polarity of the three peaks follows the order: carbon-centered radical adduct > oxygen-centered radical adduct > nitrogen-centered radical adduct. The last has a polarity that is weaker than 3-MI. Only the nitrogen-centered peak and the 3-MI peak possessed radioactivity. The retention time of the nitrogen centered radical is the same as the spin adduct generated by 3-MI irradiation with ultraviolet light. These results demonstrate that the nitrogen-centered radical is a 3-MI-PBN spin adduct, and supports the hypothesis that 3-MI-induced lung damage results from activation of 3-MI to a free radical. Also, in this study the stability of the radical spin adducts and the best conditions to produce the radicals in the incubation system was investigated.
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2368
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Cook GM, Rainey FA, Chen G, Stackebrandt E, Russell JB. Emendation of the description of Acidaminococcus fermentans, a trans-aconitate- and citrate-oxidizing bacterium. INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY 1994; 44:576-8. [PMID: 8068544 DOI: 10.1099/00207713-44-3-576] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Ruminal fluid which was enriched with trans-aconitate yielded a gram-negative diplococcus (strain AO) which was identified by 16S ribosomal DNA sequence analysis as Acidaminococcus fermentans. In contrast to the original description, the A. fermentans type strain and strain AO were found to utilize citrate as an energy source and to produce hydrogen and hydrogen sulfide. The descriptions of the genus and species are emended accordingly.
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2369
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Cheng-Bennett A, Chan MF, Chen G, Gac T, Garst ME, Gluchowski C, Kaplan LJ, Protzman CE, Roof MB, Sachs G. Studies on a novel series of acyl ester prodrugs of prostaglandin F2 alpha. Br J Ophthalmol 1994; 78:560-7. [PMID: 7918269 PMCID: PMC504864 DOI: 10.1136/bjo.78.7.560] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A novel series of prostaglandin F2 alpha (PGF2 alpha) prodrugs, with acyl ester groups at the 9, 11, and 15 positions, was prepared in order to design clinically acceptable prostaglandins for treating glaucoma. Studies involving isolated esterases and ocular tissue homogenates indicated that 9-acyl esters cannot provide a prodrug since PGF2 alpha would not be formed as a product. In contrast, 11-mono, 15-mono, and 11, 15-diesters were converted to PGF2 alpha in ocular tissues and could, therefore, be considered as prodrugs of PGF2 alpha. Carboxylesterase (CE) appeared critically important for the hydrolytic conversion of those PGF2 alpha prodrugs where the 11 or 15-OH group was esterified and such prodrugs were not substrates for acetylcholinesterase (ACHE) or butyrylcholinesterase (BuCHE). The enzymatic hydrolysis of PGF2 alpha-1-isopropyl ester was also investigated for comparative purposes. This PGF2 alpha prodrug was a good substrate for CE, but was also hydrolysed by BuCHE, albeit at a much slower rate. The most striking feature of the enzymatic hydrolysis of PGF2 alpha-1-isopropyl ester in ocular tissue homogenates was that it was much faster than for prodrugs esterified at the 11 and/or 15 positions. In terms of ocular hypotensive activity, all prodrugs which showed detectable conversion to nascent PGF2 alpha were potent ocular hypotensives. Although no separation of ocular hypotensive and ocular surface hyperaemic effects was apparent for PGF2 alpha-1-isopropyl ester, a temporal separation of these effects was apparent for the novel PGF2 alpha ester series. This difference may reflect an unfavourably rapid conversion of PGF2 alpha-1-isopropyl ester in ocular surface tissues compared with anterior segment tissues.
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2370
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DeLisi LE, Devoto M, Lofthouse R, Poulter M, Smith A, Shields G, Bass N, Chen G, Vita A, Morganti C. Search for linkage to schizophrenia on the X and Y chromosomes. AMERICAN JOURNAL OF MEDICAL GENETICS 1994; 54:113-21. [PMID: 8074161 DOI: 10.1002/ajmg.1320540206] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Markers for X chromosome loci were used in linkage studies of a large group of small families (n = 126) with at least two schizophrenic members in one sibship. Based on the hypothesis that a gene for schizophrenia could be X-Y linked, with homologous loci on both X and Y, our analyses included all families regardless of the pattern of familial inheritance. Lod scores were computed with both standard X-linked and a novel X-Y model, and sib-pair analyses were performed for all markers examining the sharing of maternal alleles. Small positive lod scores were obtained for loci pericentromeric, from Xp11.4 to Xq12. Lod scores were also computed separately in families selected for evidence of maternal inheritance and absence of male to male transmission of psychosis. The lod score for linkage to the locus DXS7 reached a maximum of 1.83 at 0.08% recombination, assuming dominant inheritance on the X chromosome in these families (n = 34). Further investigation of the X-Y homologous gene hypothesis focussing on this region is warranted.
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2371
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Ji MX, He NS, Wang P, Chen G. Use of selective embolization of the bilateral cavernous arteries for posttraumatic arterial priapism. J Urol 1994; 151:1641-2. [PMID: 8189586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Nonischemic arterial high flow priapism caused by traumatic laceration of a branch of the penile cavernous artery is rare. We report a case of laceration of the left and right branches of the intracavernous artery, which was confirmed by selective internal pudendal arteriography. Bilateral cavernous artery embolization was performed using gelatin sponge and detumescence occurred immediately. Normal potency was evident 4 months later. Our case demonstrates that selective cavernous arterial embolization is a safe and effective therapy for arterial priapism and that erectile function can return to normal.
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2372
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Wang J, Yang S, Chen G, Li D, Pang A, Tian H. Contents of trace elements in the hair of aplastic anemia patients and their treatment based on an overall analysis of symptoms and signs. J TRADIT CHIN MED 1994; 14:98-100. [PMID: 7967704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The content of 12 trace elements in the hair of 20 aplastic anemia patients was determined and compared with that of normal subjects as control. The results showed that patients with deficiency of yin had a significant decrease in lithium, calcium, strontium, and chromium, those with deficiency of yang had a distinct decrease in zinc magnesium barium, strontium, calcium, and lithium, and those with deficiency of both yin and yang had a general decrease in all the 12 trace elements. Changes in trace element content in hair may serve as a guide to opening up new vistas in the treatment of aplastic anemia on the basis of an overall analysis of symptoms and signs.
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2373
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Mackow ER, Fay ME, Shaw R, Tao H, Chen G. Cloning sequencing and expression of the gene encoding the VP2 protein of the human group B rotavirus, ADRV. Virology 1994; 201:162-8. [PMID: 8178482 DOI: 10.1006/viro.1994.1279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Adult diarrheal rotavirus, ADRV, is a noncultivable human group B rotavirus. A complete cDNA copy of ADRV gene segment 2 has been cloned and sequenced. Gene segment 2 contains 2844 bases and encodes one long open reading frame beginning at base 14 and terminating at base 2812. Gene 2 encodes a protein containing 933 amino acids with a calculated molecular weight of 105.6 kDa and a pl of 5.5. The gene 2 polypeptide contains significant homology with the VP2 protein which comprises the core of group A rotavirus strains. The gene 2 protein has been expressed in a rabbit reticulocyte lysate in vitro and is identical in molecular mass with a protein previously demonstrated to be present on iodinated EDTA-treated virions and from in vitro translations of total ADRV mRNA. A recombinant baculovirus containing gene segment 2 has been constructed and used to express the encoded VP2 equivalent protein. The expressed VP2 protein is immunoprecipitable by hyperimmune anti-ADRV serum, porcine group B infection serum, and human convalescent serum but not by hyperimmune serum to group A rotavirus. Our results suggest that ADRV gene segment 2 encodes the VP2 protein equivalent to group A rotavirus strains present in the core of the group B virion.
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2374
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Kong Q, Williams M, Chen G. The indefinite closed world assumption. DATA KNOWL ENG 1994. [DOI: 10.1016/0169-023x(94)90030-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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2375
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Reddick WE, Langston JW, Meyer WH, Gronemeyer SA, Steen RG, Chen G, Taylor JS. Discrete signal processing of dynamic contrast-enhanced MR imaging: statistical validation and preliminary clinical application. J Magn Reson Imaging 1994; 4:397-404. [PMID: 8061439 DOI: 10.1002/jmri.1880040327] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
A high-resolution image-based method was developed to analyze dynamic contrast agent-enhanced magnetic resonance images quantitatively. This method determines the initial rate of contrast agent accumulation, the delayed rate of accumulation, and the maximum enhancement in each pixel. These three parameters allow characterization of the dynamic signal features. Simulated noisy test sets of dynamic enhancement curves have shown this method to yield a fast and accurate characterization of the dynamic signal. Clinical examples of both qualitative image parameter maps and quantitative statistical analysis of the parameter distributions demonstrated the quality and potential of the technique. The technique is designed to yield imaging and quantitative information on contrast agent accumulation that can be useful in detecting residual tumor and evaluating response to therapy, while requiring less than 7 minutes of imaging time and 5 minutes of processing time per study.
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2376
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Li Z, Chen G. [Evaluation of theophylline population pharmacokinetics in adult hospitalized patients using NONMEM analysis]. ZHONGGUO YAO LI XUE BAO = ACTA PHARMACOLOGICA SINICA 1994; 15:267-70. [PMID: 7976385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The population pharmacokinetics of theophylline was evaluated using 374 theophylline serum concentration measurements from 72 hospitalized patients through NONMEM analysis. An one-compartment open pharmacokinetic model with first-order absorption and first-order elimination was used. The effects of a variety of factors on Cl and Vd were investigated. Hypothesis testing to evaluated potentially significant factors produced a final regression model. There were about 1.25% per year decrease in Cl at the age of 18-77. Cl was reduced by 26.8% for patients with long history of theophylline administration and multiple dosings, and reduced by 33.9% in OLD patients. Sex, body weight, and coadministration of acetylspiramycin had no significant effects on Cl. Vd was proportional to body weight. The final regression model allowed a priori estimate of the theophylline pharmacokinetic parameters in the patients. These results may be helpful to a rational individualized theophylline dosage regimen.
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2377
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Chen G, Wu Y, Xu X. [An experimental model of electric injury by high voltage]. 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 1994; 10:209-11. [PMID: 7834527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A standardized 10,000-volt, 2 + 0.15-A, 5-s electric burn rabbit model was established. Microscopic examination revealed that there was patchy cellular necrosis intermingled with viable cells in the muscle in the burn area. Grossly, there was a distinct interface between viable and nonviable tissues. The resulted injury correlated well with clinical features of electric burn.
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2378
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Chen G, Bressler BH, Quinn LS. Extracts from mdx and normal mouse skeletal muscle contain similar levels of mitogenic activity for myoblasts. Cell Biol Int 1994; 18:229-35. [PMID: 8044140 DOI: 10.1006/cbir.1994.1068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The mdx mouse has been used as an animal model for human Duchenne muscular dystrophy (DMD). Unlike DMD, skeletal muscles of mdx mice undergo successful regeneration and do not show extensive fibrosis and functional impairment. Growth factors have been proposed to be involved in muscle growth and regeneration. We compared mitogenic activity for skeletal myoblasts released after injury in mdx and control mice, using crushed muscle extract (CME) as a model system. We found that CMEs from normal and mdx mice contained similar mitogenic activities per microgram protein, and produced similar maximal levels of mitogenic stimulation. Skeletal muscles from mdx mice, however, released higher amounts of CME protein per gram of muscle weight compared to controls, possibly as a result of histological or physiological alterations in mdx muscle tissue. Adequate mitogenic activity in CME from mdx muscles may be related to successful muscle regeneration in mdx mice.
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2379
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Chen G, Waxman DJ. Role of cellular glutathione and glutathione S-transferase in the expression of alkylating agent cytotoxicity in human breast cancer cells. Biochem Pharmacol 1994; 47:1079-87. [PMID: 8147907 DOI: 10.1016/0006-2952(94)90420-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Glutathione (GSH) and glutathione S-transferases (GSTs) play an important role in the protection of cells against toxic effects of many electrophilic drugs and chemicals. Modulation of cellular GSH and/or GST activity levels provides a potentially useful approach to sensitizing tumor cells to electrophilic anti-cancer drugs. In this study, we describe the interactions of four representative alkylating agents (AAs), melphalan, 4-hydroperoxy-cyclophosphamide (4HC), an an activated form of cyclophosphamide, 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), and cisplatin, with GSH and GST in the human breast cancer cell line MCF-7. Depletion of cellular GSH pools by approximately 80% by treatment of the cells with the GSH synthesis inhibitor buthionine sulfoximine (BSO) sensitized the tumor cells to each AA to a different extent, with dose-modifying factors of 2.39, 2.21, 1.64, and 1.27 observed for melphalan, 4HC, cisplatin, and BCNU, respectively. Treatment of the cells with the GST inhibitor ethacrynic acid (EA) failed to show any significant effects on the cytotoxicity of these AAs. However, EA did potentiate the cytotoxicity of melphalan when given in combination with BSO, an effect that may be due to a more complete depletion of cellular GSH levels by the combined modulator treatment. Following a 1-hr exposure to cytotoxic-equivalent concentrations of these AAs, GSH levels decreased substantially in the case of 4HC and BCNU, but increased by 30-50% in the case of cisplatin and melphalan. BSO pretreatment largely blocked this effect of cisplatin and melphalan on cellular GSH, while it further enhanced the GSH-depleting activity of both 4HC and BCNU. On the basis of these results, it is concluded that (a) GSH affects the cytotoxicity of different AAs to different extents, (b) basal GST expression in MCF-7 cells does not play a major role in AA metabolism, (c) EA can potentiate the enhancing effect of BSO on melphalan cytotoxicity in MCF-7 cells, and (d) depletion of cellular GSH by pretreatment with BCNU or cyclophosphamide may correspond to a useful strategy for enhancing the anti-tumor activity of other AAs given in a sequential combination.
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2380
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Chen G, Wilson R, Cumming G, Walker JJ, McKillop JH. Immunological changes in pregnancy-induced hypertension. Eur J Obstet Gynecol Reprod Biol 1994; 53:21-5. [PMID: 8187916 DOI: 10.1016/0028-2243(94)90132-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Aspects of T and B cell function were studied in women with pregnancy-induced hypertension (PIH) and normotensive pregnant women by determining the proliferation of peripheral blood mononuclear cells (PBMC) with or without stimulation by mitogens (PHA, ConA and PWM) and by determining IgG and IgM levels in the culture supernatant. The results showed that the proliferation of PBMC without mitogens was significantly increased in PIH women without proteinuria compared with normotensive pregnant women. In the presence of PHA, [3H]thymidine uptake in PBMC was statistically higher in PIH women both with and without proteinuria than that in normotensive pregnant women. ConA and PWM mitogen activities were not significantly different between PIH women and normotensive pregnant women. Compared with normotensive pregnant women, IgG production was significantly increased in PIH women with proteinuria but not in those without proteinuria. IgM production was not changed in PIH women. We concluded that immunologic responses in PIH women were increased rather than decreased. This increased immunologic activity is in accordance with some important changes seen in PIH, such as an increase in intracellular calcium, the presence of blood-borne mitogenic factor and a decrease in prostaglandin E series. These findings also support the hypothesis that PIH might result from the imbalance between fetal antigenic load and maternal production of immunologic blockade.
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2381
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Lin X, Chen G, Li J. [Hepatic ultrasonographic imaging and serum amino acid levels in cured schistosomiasis cases]. ZHONGGUO JI SHENG CHONG XUE YU JI SHENG CHONG BING ZA ZHI = CHINESE JOURNAL OF PARASITOLOGY & PARASITIC DISEASES 1994; 12:143-146. [PMID: 7955167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Ultrasonography (B mode) of liver and serum amino-acid levels were studied in 15 cases of schistosomiasis japonica who had been cured for more than 5-15 years. Typical B-ultrasonic images of hepatic fibrosis due to schistosomiasis were found in all patients which could be classified into three types, namely, the spotty type (I), the tortoise-shell type (II) and the net-patchy type (III) according to the patterns of echogenic bands. Moderate to marked echogenic thickening of portal vein wall, and dilation of portal and splenic veins were revealed in patients with type II and III images. Free amino acids in sera were determined by using HPLC-AAAS. The result revealed that the concentration of 8 nonessential and 3 essential amino acids (threonine, valine, tryptophan) were significantly decreased in the 15 patients. The ratio of aromatic to aliphatic amino acid was markedly elevated in 3 patients of type III. The serum amino acid imbalance was attributed to the severe hepatic damage and impaired liver function.
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2382
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Woodward DF, Chan MF, Burke JA, Cheng-Bennett A, Chen G, Fairbairn CE, Gac T, Garst ME, Gluchowski C, Kaplan LJ. Studies on the ocular hypotensive effects of prostaglandin F2 alpha ester prodrugs and receptor selective prostaglandin analogs. JOURNAL OF OCULAR PHARMACOLOGY 1994; 10:177-93. [PMID: 8207325 DOI: 10.1089/jop.1994.10.177] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The use of natural prostaglandins (PG), such as PGD2, PGE2, PGF2 alpha, and PGI2, for treating glaucoma is limited by their ocular side effects. One approach to achieve the required separation of ocular hypotensive activity from side effects is to employ ester prodrugs. From a novel series of 11- and 15-mono and 11,15-diacyl esters of PGF2 alpha we identified prodrugs where PGF2 alpha formation rates in the iris-ciliary body exceeded those in the conjunctiva, sclera, and corneal endothelium. Compared to PGF2 alpha-1-isopropyl ester the ocular tissue hydrolysis rates of the 11-monopivaloyl, the 11,15-dipivaloyl ester and the 1,11-lactone were up to 1000 fold less. Despite this large disparity in hydrolysis rates, the pivaloyl esters and the 1,11-lactone were potent ocular hypotensives in our animal models. In studying prostaglandin analogs, we found that a diverse variety of prostanoid receptor selective agonists lowered intraocular pressure in dogs and/or monkeys. These included DP-, EP1-, EP2-, EP3-, and FP-receptor selective compounds. These findings were surprising and prompted us to re-examine the receptor selectivity of these agonists by radioligand binding studies. Using radiolabelled PGE2, 17-phenyl PGF2 alpha, and sulprostone we were able to confirm the selectivity of the agonists currently used for receptor characterization directly by radioligand binding competition studies. It appears that multiple prostanoid receptor subtypes may be involved in regulating intraocular pressure.
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2383
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Chen G, Hoffman AS. Synthesis of carboxylated poly(NIPAAm) oligomers and their application to form thermo-reversible polymer-enzyme conjugates. JOURNAL OF BIOMATERIALS SCIENCE. POLYMER EDITION 1994; 5:371-82. [PMID: 8025032 DOI: 10.1163/156856294x00086] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A thermo-reversible poly(N-isopropylacrylamide) poly(NIPAAm) oligomer with a carboxyl functional end group has been synthesized by radical polymerization using beta-mercaptopropionic acid as a chain transfer reagent. This polymer has been conjugated to an enzyme, beta-D-glucosidase, to form a thermo-reversible water soluble-insoluble polymer-enzyme conjugate. This conjugate can be used for separation, recovery and recycle of an enzyme simply by applying small temperature changes to the reaction medium. In contrast to the random polymer-enzyme conjugates reported in the literature, in this study the enzyme is coupled to each polymer chain by a single end attachment. These preliminary studies show that the conjugated enzyme exhibits very high retention of activity (> 90%) compared to the native enzyme and shows improved thermal stability.
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2384
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Clarke HM, Chen G. Enhanced peripheral neovascularization of musculocutaneous flaps following pedicle ligation in the pig. Plast Surg (Oakv) 1994. [DOI: 10.4172/plastic-surgery.1000084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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2385
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Li Z, Chen G, Zhuo HT. Application of NONMEM method for evaluation of relative biological availability of ofloxacin. ZHONGGUO YAO LI XUE BAO = ACTA PHARMACOLOGICA SINICA 1994; 15:39-42. [PMID: 8010083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The nonlinear mixed effect model (NONMEM) method for analysis of population pharmacokinetics, was applied to evaluate the relative biological availability of 2 ofloxacin (Ofl) products. The data of randomized crossover study of 2 kinds of Ofl tablets in 12 healthy volunteers were analyzed by NONMEM, as well as standard approach. The relative biological availability evaluated by NONMEM (F = 97.3 +/- 5.0%) was close to that by standard approach (F = 98.2 +/- 3.6%). NONMEM was also valid in accurately evaluating the relative biological availability using sparse clinical data (F = 91.7 +/- 8.0%) which could not be analyzed by standard approach. Thus, the usefulness and advantages of NONMEM were ascertained for the evaluation of biological availability using observational or experimental data.
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2386
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Jain SC, Boldy D, Chen G. Attributes of effective managers and implications for health care management education in the Asia-Pacific region. Asia Pac J Public Health 1994; 7:39-59. [PMID: 8074945 DOI: 10.1177/101053959400700108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This paper explores the perceptions of managers and students from 11 countries in the Asia-Pacific region regarding the attributes needed for becoming effective managers and the broad implications of these findings for health care management education. The study forms part of a wider international project aimed at exploring the role of national culture in managerial behavior and effectiveness.
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2387
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Chen G, Wilson R, Cumming G, Walker JJ, Smith WE, McKillop JH. Intracellular and extracellular antioxidant buffering levels in erythrocytes from pregnancy-induced hypertension. J Hum Hypertens 1994; 8:37-42. [PMID: 8151605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Both intracellular (lysate thiol, lysate glutathione and lysate superoxide dismutase) and extracellular (plasma thiol, plasma glutathione and membrane thiol) antioxidant buffering levels were measured in red blood cells from patients with pregnancy-induced hypertension (PIH). We found the following. (1) The levels of plasma thiol and plasma glutathione in PIH women with proteinuria were markedly lower than that in the normal pregnancy. (2) The concentrations of lysate glutathione and superoxide dismutase in PIH women with proteinuria were significantly decreased compared with that in the normal pregnancy. (3) With the exception of plasma and lysate glutathione, all the tested antioxidant markers were not significantly different between PIH women without proteinuria and normal pregnancy. (4) There was no statistical correlation between antioxidant buffering level and BP in patients with PIH. We concluded that both extracellular and intracellular antioxidant buffering levels were decreased in patients with PIH, especially in those with proteinuria. The reduction of the antioxidant buffering level could account for several important pathophysiological features of PIH, such as the elevation of intracellular calcium, decreased red blood cell deformability and endothelial damage.
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2388
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Abstract
Tumor suppressor genes have been identified by the occurrence of mutations in many families with hereditary forms of cancer, exposed during development of the tumor by loss of heterozygosity. They have a number of diverse functions. For example, both the RB gene of retinoblastoma and the p53 gene, which is commonly mutated in breast and colon cancer among others, produce proteins involved in distinct steps of cell cycle control, while the nm23 product prevents metastasis. Here we review the data developed until now on the possible presence and role of mutations in these and other tumor suppressor genes in breast cancer. A more complete understanding of the tumor suppressor genes could not only provide diagnostic information, but could lead to specific gene therapy to replace suppressor functions lost in individual tumors.
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2389
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Chen G, Wilson R, McKillop JH, Smith WE, Walker JJ. Calcium channel blockers and antioxidant levels. J Clin Pharm Ther 1993. [DOI: 10.1111/j.1365-2710.1993.tb00878.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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2390
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Morris SA, Florant G, Saxon M, Chen G, Bilezikian JP. Adaptations of myocardial beta-adrenergic receptor complex in hibernating marmots. THE AMERICAN JOURNAL OF PHYSIOLOGY 1993; 265:R1430-8. [PMID: 8285287 DOI: 10.1152/ajpregu.1993.265.6.r1430] [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: 01/29/2023]
Abstract
Properties of marmot (Marmota flaviventris) myocardial beta-adrenergic receptor complex (beta-AR) were evaluated during hibernation (H), in summer (S) animals, and in animals aroused from hibernation (C). The results obtained for S and C animals were identical, and only the results for C animals are shown. In H-animal myocardial membrane preparations assayed at 37 degrees C, isoproterenol-dependent adenylate cyclase activity (ACA) was consistently higher, whereas the synergistic contribution of 5'-guanylylimidodiphosphate [Gpp(NH)p] in this reaction was reduced. When assayed at 10 degrees C, only the ACA in H animals responded to the combination of isoproterenol and Gpp(NH)p. In contrast, at 10 degrees C, ACA in response to Gpp(NH)p alone is essentially equal in H and C animals. Hibernation did not change myocardial beta-AR receptor density or affinity. In contrast, analysis of isoproterenol displacement of [125I]iodocyanopindolol revealed that the proportion of beta-AR in the high-affinity state was substantially greater in H than in C animals, and this relationship was retained even in the presence of Gpp-(NH)p. In an evaluation of the role of the GTP binding proteins that couple the beta-AR to the effector adenyl cyclase, we determined that there was no change in the cholera toxin- or pertussis toxin-dependent ADP ribosylation patterns. Immunochemical detection of the individual GTP binding proteins revealed no change in the levels of G alpha i1, G alpha i2, or G alpha i3. In contrast, we observed a hibernation-associated decrease in G alpha o associated with the plasma membrane-enriched particulate fraction. (ABSTRACT TRUNCATED AT 250 WORDS)
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2391
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Manji HK, Etcheberrigaray R, Chen G, Olds JL. Lithium decreases membrane-associated protein kinase C in hippocampus: selectivity for the alpha isozyme. J Neurochem 1993; 61:2303-10. [PMID: 8245981 DOI: 10.1111/j.1471-4159.1993.tb07474.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We investigated the effects of lithium on alterations in the amount and distribution of protein kinase C (PKC) in discrete areas of rat brain by using [3H]phorbol 12,13-dibutyrate quantitative autoradiography as well as western blotting. Chronic administration of lithium resulted in a significant decrease in membrane-associated PKC in several hippocampal structures, most notably the subiculum and the CA1 region. In contrast, only modest changes in [3H]phorbol 12,13-dibutyrate binding were observed in the various other cortical and subcortical structures examined. Immunoblotting using monoclonal anti-PKC antibodies revealed an isozyme-specific 30% decrease in hippocampal membrane-associated PKC alpha, in the absence of any changes in the labeling of either the beta (I/II) or gamma isozymes. These changes were observed only after chronic (4 week) treatment with lithium, and not after acute (5 days) treatment, suggesting potential clinical relevance. Given the critical role of PKC in regulating neuronal signal transduction, lithium's effects on PKC in the limbic system represent an attractive molecular mechanism for its efficacy in treating both poles of manic-depressive illness. In addition, the decreased hippocampal membrane-associated PKC observed in the present study offers a possible explanation for lithium-induced memory impairment.
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2392
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Chen G, Mazumder MM, Chemla YR, Serpenguzel A, Chang RK, Hill SC. Wavelength variation of laser emission along the entire rim of slightly deformed microdroplets. OPTICS LETTERS 1993; 18:1993. [PMID: 19829469 DOI: 10.1364/ol.18.001993] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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2393
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Molchan SE, Manji H, Chen G, Dou L, Little J, Potter WZ, Sunderland T. Effects of chronic lithium treatment on platelet PKC isozymes in Alzheimer's and elderly control subjects. Neurosci Lett 1993; 162:187-91. [PMID: 8121626 DOI: 10.1016/0304-3940(93)90592-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Patients with Alzheimer's disease (AD) have been reported to have abnormalities in peripheral cells similar to some of those found in the brain, including decreased levels of protein kinase C (PKC) in fibroblasts. Since increasing evidence suggests that lithium affects PKC function, we investigated the effects of 3 weeks of lithium administration on the immunolabeling of 4 PKC isozymes (alpha, beta, epsilon, and zeta) in particulate and soluble fractions from platelets of 7 patients with probable AD and 6 age-matched controls. AD patients had significantly less particulate or membrane-associated PKC zeta than normals during the placebo phase (P < 0.003). After 3 weeks of lithium treatment, AD patients had significantly less membrane-associated PKC alpha (P < 0.002), epsilon (P < 0.003), and zeta (P < 0.001) than normals. This is the first report of a difference in PKC in blood cells between AD and control subjects. These findings appear to indicate that some PKC isozymes may be differentially regulated in AD versus elderly controls, at least as evidenced in this peripheral cellular system.
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2394
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Chen G, Wilson R, Cumming G, Walker JJ, McKillop JH. Production of prostacyclin and thromboxane A2 in mononuclear cells from preeclamptic women. Am J Obstet Gynecol 1993; 169:1106-11. [PMID: 8238168 DOI: 10.1016/0002-9378(93)90264-j] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE Although the changes in prostacyclin and thromboxane A2 levels in preeclampsia have been well studied, little work has previously been done on mononuclear cells, and the cause of the changes in unclear. We determined the prostacyclin and thromboxane A2 production in mononuclear cells and investigated the effect of preeclamptic serum on this production. STUDY DESIGN The production of prostacyclin and thromboxane A2 was measured by enzyme immunoassay in 16 normal pregnant women, nine preeclamptic women with proteinuria, and six preeclamptic women without proteinuria. Sera from these three groups of women were investigated to see whether the sera have any effect on prostaglandin production. RESULTS The levels of thromboxane A2 in preeclamptic patients were found to be much higher than those of normal pregnancy, whereas the levels of prostacyclin tended to be lower. Such changes lead to a markedly increased ratio of thromboxane A2 to prostacyclin in preeclamptic patients. There was no difference in the levels of prostacyclin and thromboxane A2 between the preeclamptic patients with and without proteinuria. Serum from preeclamptic patients with proteinuria slightly reduced prostacyclin synthesis in normal pregnancy but significantly increased increased thromboxane A2 production, resulting in a ratio of thromboxane A2 to prostacyclin similar to that of preeclampsia. However, serum from preeclamptic patients without proteinuria failed to exert such effects. CONCLUSION The imbalance between prostacyclin and thromboxane A2 occurs in mononuclear cells from preeclamptic women, and there is a factor(s) in proteinuric-preeclamptic serum to contribute, in part, to these changes. Our findings also suggested that the cause of abnormal prostaglandin production in preeclampsia was complicated and multifactorial.
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2395
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Lu JF, Wu MF, Chen G, Xiang BR, An DK. Midazolam pharmacokinetics and electroencephalographic changes in eight Chinese men. ZHONGGUO YAO LI XUE BAO = ACTA PHARMACOLOGICA SINICA 1993; 14:485-8. [PMID: 8010043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Eight Chinese healthy male volunteers aged 27 +/- s 4 a were injected i.v. midazolam (Mid) 15 mg. Blood samples were collected at 0, 2, 5, 7, 10, 20, 30, 45, 60, 90, 120, 180, and 240 min. A HPLC method was established for determining the Mid concentrations in serum. The concentration-time data was fitted with biexponential curve. Pharmacokinetic parameters were: T1/2 alpha = 6.8 +2- 2.5 min, T1/2 beta = 118 +/- 27 min, Vc = 25 +/- 7 L, Cl = 393 +/- 79 ml.min-1, Vdss = 59 +/- 13 L, AUC0-infinity = 39.6 +/- 8.6 g.min.L-1. The electroencephalogram (EEG) showed a decrease in alpha activity and an increase in beta activity. The EEG pattern reverted toward baseline after 2-3 h. Pharmacokinetic and EEG findings suggest that Mid is a preferable anesthesia inducing agent.
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2396
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Chen G, Guo Y, Karasawa N, Goddard WA. Electron-phonon interactions and superconductivity in K3C60. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 48:13959-13970. [PMID: 10007797 DOI: 10.1103/physrevb.48.13959] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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2397
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Chen G, Hoffman AS. Preparation and properties of thermoreversible, phase-separating enzyme-oligo(N-isopropylacrylamide) conjugates. Bioconjug Chem 1993; 4:509-14. [PMID: 8305520 DOI: 10.1021/bc00024a013] [Citation(s) in RCA: 131] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A thermoreversible N-isopropylacrylamide (NIPAAm) oligomer with an N-hydroxysuccinimide (NHS) ester functional end group has been prepared for coupling to an enzyme, beta-D-glucosidase, to form a thermoreversible, phase-separating polymer-enzyme conjugate. This conjugate can be used for separation, recovery, and recycle of an enzyme simply by applying small temperature changes to the reaction medium. In contrast to the random polymer-enzyme conjugates previously reported by us and others in the literature, in this study the conjugate is formed by a single, end attachment of each oligomer chain to the enzyme. Preliminary studies show that the conjugated enzyme exhibits very high retention of activity, even higher than native enzyme, and shows improved thermal stability compared to native enzyme.
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2398
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Sack GH, Alpern M, Webster T, Feil RP, Morrell JC, Chen G, Chen W, Caskey CT, Moser HW. Chromosomal rearrangement segregating with adrenoleukodystrophy: a molecular analysis. Proc Natl Acad Sci U S A 1993; 90:9489-93. [PMID: 8415728 PMCID: PMC47594 DOI: 10.1073/pnas.90.20.9489] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The relationship between X chromosome-linked adrenoleukodystrophy and the red/green color pigment gene cluster on Xq28 was investigated in a large kindred. The DNA in a hemizygous male showed altered restriction fragment sizes compatible with at least a deletion extending from the 5' end of the color pigment genes. Segregation analysis using a DNA probe within the color pigment gene cluster showed significant linkage with adrenoleukodystrophy (logarithm of odds score of 3.19 at theta = 0.0). These data demonstrate linkage, rather than association, between a unique molecular rearrangement in the color pigment gene cluster and adrenoleukodystrophy. The DNA changes in this region are thus likely to be helpful for determining the location and identity of the responsible gene.
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2399
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Crow TJ, Poulter M, Lofthouse R, Chen G, Shah T, Bass N, Morganti C, Vita A, Smith C, Boccio-Smith A. Male siblings with schizophrenia share alleles at the androgen receptor above chance expectation. AMERICAN JOURNAL OF MEDICAL GENETICS 1993; 48:159-60. [PMID: 8291571 DOI: 10.1002/ajmg.1320480309] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In families that included two or more siblings with schizophrenia or schizo-affective disorder male-male pairs were found to share alleles at the androgen receptor (AR) gene (in Xq11.2-q12) above chance expectation (p < 0.003); female-female and mixed sex pairs showed no such tendency. The findings are compatible with X-Y linkage or with an X-linked contribution to liability in males.
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2400
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Chen W, Xu R, Chen G, Zao J, Chen T. Changes of the prevalence of endemic fluorosis after changing water sources in two villages in Guangdong, China. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 1993; 51:479-482. [PMID: 8400647 DOI: 10.1007/bf00192160] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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