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Yin M, Kurvers HA, Buurman WA, Tangelder GJ, Tiebosch AT, Daemen JH, Kootstra G. Platelet-activating factor antagonist TCV-309 protects rat kidneys against ischemia-reperfusion injury. Transplant Proc 1995; 27:2844-6. [PMID: 7482939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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202
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Yin M, Kurvers HA, Tangelder GJ, Booster MH, Daemen JH, Kootstra G. Intravital microscope studies of the ischemically injured rat kidney during the early phase of reperfusion. Transplant Proc 1995; 27:2847-8. [PMID: 7482940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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203
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Diehl AM, Yang SQ, Yin M, Lin HZ, Nelson S, Bagby G. Tumor necrosis factor-alpha modulates CCAAT/enhancer binding proteins-DNA binding activities and promotes hepatocyte-specific gene expression during liver regeneration. Hepatology 1995; 22:252-61. [PMID: 7601419 DOI: 10.1016/0270-9139(95)90379-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Injury-related cytokines, such as tumor necrosis factor-alpha (TNF), may preserve liver-specific gene expression during the subsequent regenerative response by modulating the activity of transcription factors, including CCAAT/enhancer binding proteins (C/EBPs), which regulate differentiated gene expression in hepatocytes. To test this theory, rats were treated with neutralizing antibody to TNF or nonimmune immunoglobulin before partial hepatectomy (PH) and regenerative changes in the messenger RNAs (mRNAs), proteins, and DNA-binding activities of C/EBP isoforms and the expression of a C/EBP-regulated gene, phosphoenol pyruvate carboxykinase (PEPCK), were compared. Before PH, the expressions of C/EBP-alpha, C/EBP-beta, and C/EBP-gamma were similar in the two treatment groups. Dimers containing C/EBP-alpha and C/EBP-beta accounted for virtually all of the C/EBP DNA binding activity and mRNA for PEPCK, the rate limiting hepatocyte enzyme for gluconeogenesis, was barely detected. After PH, in control rats, mRNA and nuclear protein concentrations of C/EBP-beta and C/EBP-gamma increased approximately fivefold by 3 hours after PH. This was accompanied by increased DNA binding activity of these C/EBP isoforms and decreased DNA binding activity of C/EBP-alpha. mRNA levels of PEPCK, a gene that is strongly transactivated by non-alpha C/EBP isoforms, increased fivefold. Pretreatment with anti-TNF antibodies prevented regenerative induction of C/EBP beta and gamma expression and DNA-binding activity. The nature of dimers binding to C/EBP cis-acting elements remained similar to that observed in liver before PH and increases in PEPCK mRNA were blunted. These results support the theory that TNF helps maintain liver-specific gene expression during liver regeneration by altering transcription factor complexes that regulate differentiated gene expression in hepatocytes.
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Jiang ZH, Lu JL, Qu FJ, Yin M, Huang SK. [Synaptic connections between the neurons and catecholaminegic fibres in the hippocampal transplant of rat]. SHENG LI XUE BAO : [ACTA PHYSIOLOGICA SINICA] 1995; 47:281-6. [PMID: 7570115] [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 foetal hippocampal tissue (transplant) at 17th day of embryonic age was implanted into the ventral hippocampus of adult rats (host). The catecholaminergic fibre projections in the hippocampal transplants 90 days after operation were studied by immunohistochemical technique. It was observed that in the host hippocampus there was a large population of TH- immunoreactive slender fibres of only 0.5-1 microns in diameter. These fibres were distributed more densely in the hippocampal hilus and CA3 transparent layers than in molecular layers, but sparsely in pyramidal or granular layers. In the molecular and cellular layers of transplanted hippocampus some thicker (> 1 micron) TH-positive fibers were ended in a relatively dense branching. The immunoelectron-microscopic observations showed that many TH-positive boutons made synaptic contacts with immunonegative dendrites and dendritic spines in the hippocampal transplants, the majority of which were asymmetrical synapses with a 30 nm synaptic cleft and conspicuously thickened postsynaptic membranes. It is concluded that catecholaminergic fibres extend from the host brain into the hippocampal transplant to establish synapses with the target neurons.
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Booster MH, Yin M, Maessen JG, Stubenitsky BM, Wijnen RM, Kootstra G. Protection of canine renal grafts by renin-angiotensin inhibition through nucleoside transport blockade. Transpl Int 1995; 8:207-13. [PMID: 7626181 DOI: 10.1007/bf00336539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The aims of this study were (1) to investigate the effect of R 75231, a nucleoside transport inhibitor, on renin-angiotensin release after renal ischemia-reperfusion and (2) to establish a possible protective effect of this drug on renal function. We used a canine model for auto- transplantation of kidneys that had been subjected to 30 min of warm ischemia and subsequently to 24h of cold storage in HTK preservation solution, with immediate contralateral nephrectomy. R 75231 was injected intravenously into six dogs in two equal portions of 0.05 mg/kg both 30 min and 10 min before reanastomosis was established. Another six dogs were used as a control group. At 2 weeks post-transplantation, five out of six dogs in the R 75231 group and one out of six in the control group were still alive. Starting on day 4, serum creatinine was lower in the R 75231 group than in the control group (p < 0.005). In contrast to the control group, an inversion of the median preischemia adenosine/inosine ratio was observed in the R 75231 group after reperfusion (0.4 preischemia vs 4.0 after 60 min of reperfusion). Reperfusion of the graft resulted in an immediate increase in renin, angiotensin I, and angiotensin II venous blood levels in the control group. In the R 75231 group, renin, angiotension I, and angiotensin II levels were significantly lower. We conclude that administration of R 75231 before reperfusion has a protective effect on post-transplant function of kidneys that have been subjected to prolonged warm ischemia. This effect may, at least in part, be ascribed to inhibition of the breakdown and disposal of endogenous adenosine which, in turn, inhibits the excessive stimulation of the renin-angiotensin system in the early phase of reperfusion.
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Booster M, Yin M, Maessen J, Stubenitsky B, Wijnen R, Kootstra G. Protection of canine renal grafts by reninangiotensin inhibition through nucleoside transport blockade. Transpl Int 1995. [DOI: 10.1111/j.1432-2277.1995.tb01505.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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207
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Booster M, Yin M, Kurvers HA, Tangelder GJ, Wijnen RM, Buurman WA, Heineman E, Stubenitsky BM, Kootstra G. Inhibition of CD18-dependent leukocyte adherence by mAb 6.5 E does not prevent ischemia-reperfusion injury as seen in grafted kidneys. Transpl Int 1995; 8:126-32. [PMID: 7766294 DOI: 10.1007/bf00344422] [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: 01/27/2023]
Abstract
The present study was designed to determine whether beta-2 integrin-mediated leukocyte adherence to the endothelium is involved in renal ischemia-reperfusion damage and to evaluate the therapeutic intervention potency of monoclonal antibody (mAb) 6.5 E, directed against the leukocyte CD18 adhesion molecule. To answer these questions, we used a clinically relevant canine model for the autotransplantation of kidneys that had been subjected to 30 min of normothermic ischemia, followed by 24 h of cold storage preservation. Intravital fluorescence microscopy of capsular microvessels showed that substantial leukocyte adherence occurred after renal ischemia and reperfusion. Leukocyte adherence was observed in both arterioles and venules, but predominantly in the latter. Reperfusion of the graft resulted in a statistically significant reduction of the venular red blood cell velocity (RBCV). Moreover, the venular diameter increased. No significant changes in the arteriolar RBCV or in the arteriolar diameter were observed. Administration of mAb 6.5 E, 1 h before reperfusion, inhibited leukocyte adherence to the renal microvascular endothelium, resulting in an improved venular flow 2 h after reperfusion. However, we observed no beneficial effect of mAb 6.5 E pretreatment on post-transplant graft function and survival. We conclude that leukocyte adherence does not play a critical role in the development of renal injury following reperfusion of kidneys that have been subjected to prolonged warm and cold ischemia.
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Booster M, Yin M, Kurvers H, Tangelder G, Wijnen R, Buurman W, Heineman E, Stubenitsky B, Kootstra G. Inhibition of CD18-dependent leukocyte adherence by mAb 6.5 E does not prevent ischemia-reperfusion injury as seen in grafted kidneys. Transpl Int 1995. [DOI: 10.1111/j.1432-2277.1995.tb01487.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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209
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Yin M, Kurvers HA, Buurman WA, Tangelder GJ, Booster MH, Daemen JH, Kondracki S, Kootstra G. Beneficial effect of platelet-activating factor antagonist TCV-309 on renal ischemia-reperfusion injury. Transplant Proc 1995; 27:774-6. [PMID: 7879180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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210
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Booster MH, van der Vusse GJ, Wijnen RM, Yin M, Stubenitsky BM, Kootstra G. University of Wisconsin solution is superior to histidine tryptophan ketoglutarate for preservation of ischemically damaged kidneys. Transplantation 1994; 58:979-84. [PMID: 7974736 DOI: 10.1097/00007890-199411150-00001] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The current shortage of transplantable organs has renewed interest in kidneys obtained from non-heart-beating donors. Kidneys from these donors have suffered warm ischemia (WI). The effectiveness of two preservation solutions, i.e., the University of Wisconsin (UW) and the histidine tryptophan ketoglutarate (HTK) solutions, for preservation of kidneys that have been subjected to WI was tested in dogs. The left kidney was autotransplanted after 30 min of WI, and subsequent 24-hr cold storage (CS) in either UW (n = 6) or HTK (n = 6), with immediate contralateral nephrectomy. Surgical biopsies from the cortex were taken before WI, after 30 min of WI, after 24 hr of CS, and after 1 hr of reperfusion for electron microscopy and for analysis of energy metabolites. At 2 weeks after transplantation in the UW group, 4 out of 6 and, in the HTK group, 1 out of 6 dogs survived. As from day 2, serum creatinine was lower in the UW group as compared with the HTK group (P < 0.05). After 24 hr of CS, in the HTK group the luminal membranes of proximal tubular cells were partly denuded of microvilli. Moreover, the tubular lumen was filled with blebs and debris. In the UW group, the brush borders remained intact, although microvilli were swollen. Energy metabolites were analyzed with HPLC. Thirty minutes of WI resulted in a +/- 45% reduction of total adenine nucleotide (TAN) content. During CS, TAN levels further decreased in both groups; however, after 24 hr of CS, the levels of adenosine, inosine, hypoxanthine, and xanthine were significantly higher in the UW group as compared with the HTK group (P < 0.05, P < 0.01, P < 0.01, P < 0.01). At 1 hr of reperfusion, TAN levels were higher in the UW group as compared with the HTK group (4.66 +/- 0.16 vs. 4.02 +/- 0.28, P < 0.05). Our results show that UW is a superior solution compared with HTK in the preservation of ischemically damaged kidneys, demonstrating better survival, better recovery of kidney function, better protection against ischemia-induced ultrastructural damage, and better preservation of energy metabolism indicated by (a faster) regeneration of TAN levels after reperfusion.
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Diehl AM, Yin M, Fleckenstein J, Yang SQ, Lin HZ, Brenner DA, Westwick J, Bagby G, Nelson S. Tumor necrosis factor-alpha induces c-jun during the regenerative response to liver injury. THE AMERICAN JOURNAL OF PHYSIOLOGY 1994; 267:G552-61. [PMID: 7943321 DOI: 10.1152/ajpgi.1994.267.4.g552] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
After liver injury, remaining hepatocytes proliferate to regenerate the liver. Although the precise mechanisms that initiate and localize regeneration are unknown, local induction of c-jun is a critical, early step in the response. Treatment of rats with antibodies to tumor necrosis factor-alpha (TNF-alpha), a mediator of liver injury, inhibits regenerative induction of jun nuclear kinase activity and nuclear c-jun expression and alters the DNA binding activity of the c-jun transcription factor, AP-1, in liver. Pretreatment with anti-TNF antibodies does not affect pulmonary or renal c-jun expression or AP-1 binding activity post-partial hepatectomy. In primary hepatocyte cultures, TNF-alpha directly promotes the proliferative actions of mitogens, supporting in vivo evidence that it sensitizes hepatocytes to mitogens. Thus local release of TNF may act in a paracrine fashion to initiate regeneration in the injured liver by promoting induction of critical growth-related genes, such as c-jun.
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212
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Yin M, Booster MH, vd Bogaard AE, Kootstra G. A simple technique to harvest two kidneys from one donor rat for transplantation. Lab Anim 1994; 28:387-90. [PMID: 7830381 DOI: 10.1258/002367794780745128] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Kidney transplantation in rats is a widely used and well established model in transplantation immunology and preservation research. With the conventional method, only one kidney is harvested from the donor rat. We developed a technique to harvest two kidneys separately from one donor, subsequently both kidneys were successfully implanted into two recipient rats. This technique which leads to a reduction of the number of experimental animals used is discussed in detail.
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213
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Rydel TJ, Yin M, Padmanabhan KP, Blankenship DT, Cardin AD, Correa PE, Fenton JW, Tulinsky A. Crystallographic structure of human gamma-thrombin. J Biol Chem 1994; 269:22000-6. [PMID: 8071320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
In an effort to prepare crystals and determine the structure of alpha-thrombin complexed to a synthetic peptide inhibitor (MDL-28050) of the hirudin 54-65 COOH-terminal region, it was discovered that the crystals were not those of the complex but of gamma-thrombin. Gel electrophoresis studies revealed that autolytic degradation had occurred prior to crystallization. NH2-terminal sequence analysis of these autolytic fragments confirmed the gamma-thrombin product (cleavages at Arg75-Tyr76 and/or Arg77A-Asn78, and Lys149E-Gly150; chymotrypsinogen numbering) with a minor amount of another autolysis product, beta-thrombin (first two cleavages only). The final structure has an R-factor of 0.156 for 7.0-2.5-A data, and includes 186 water molecules. A comparison of gamma-thrombin with the thrombin structure in the alpha-thrombin-hirugen complex revealed that the two structures agreed well (r.m.s. delta = 0.39 A for main chain atoms). These structures possess uninhibited active sites where the disposition of the catalytic triad residues is nearly identical. The electron density in the vicinity of the gamma-thrombin cleavage regions is poor, and only becomes well-defined several residues prior to and after the actual cleavage sites. The extensive disorder evoked by beta-cleavage(s) in the Lys70-Glu80 loop region indicates that this part of the molecule is severely disrupted by autolysis and is the reason exosite functions are dramatically impaired in beta-and gamma-thrombin. Since autolysis did not lead to a major reorganization of the folded structure of alpha-thrombin, the likely structural features of the interaction of thrombin substrate with thrombin enzyme during beta-cleavage have been modeled by docking the exosite region of one molecule at the active site of another.
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Rydel T, Yin M, Padmanabhan K, Blankenship D, Cardin A, Correa P, Fenton J, Tulinsky A. Crystallographic structure of human gamma-thrombin. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)31746-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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215
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Tsukamoto K, Yin M, Sved AF. Effect of atropine injected into the nucleus tractus solitarius on the regulation of blood pressure. Brain Res 1994; 648:9-15. [PMID: 7922532 DOI: 10.1016/0006-8993(94)91898-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Previous experiments have demonstrated that stimulation of muscarinic cholinergic receptors in the nucleus tractus solitarius (NTS) of the rat decreases arterial blood pressure and heart rate. The present studies were designed to examine the role of cholinergic mechanisms in the NTS in the tonic regulation of arterial pressure and the baroreceptor reflex. Atropine injected into the NTS of chloralose-anesthetized rats produced a dose-dependent inhibition of cardiovascular responses elicited by injection of acetylcholine into the same site; 240 pmol atropine eliminated acetylcholine-evoked responses. Atropine also increased arterial blood pressure but only at higher doses. Even larger doses of atropine were required to alter cardiovascular responses elicited by electrical stimulation of the aortic depressor nerve. Methylatropine injected into the NTS also blocked acetylcholine-evoked responses but, in contrast to the actions of atropine, did not increase arterial pressure in the dose range required to block acetylcholine-evoked responses. Furthermore, a dose of methylatropine (1 nmol) capable of blocking acetylcholine-evoked cardiovascular responses did not alter aortic depressor nerve-evoked cardiovascular responses. This lack of an effect of methylatropine on arterial pressure and aortic depressor nerve-evoked responses was not due to limited diffusion of the drug within the NTS since 1 nmol methylatropine completely blocked acetylcholine-evoked responses even when injected 0.5 mm distant from the site of acetylcholine injection. These results suggest that cholinergic mechanisms in the NTS are not involved in the tonic regulation of cardiovascular function or the baroreceptor reflex. Furthermore, these results highlight the importance of characterizing doses of drugs used in microinjection studies.
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216
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Basu A, Yin M, Waterland RA, Chance B. Kinetics of ligand binding of cytochrome oxidases: a comparative study. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1184:291-5. [PMID: 8130254 DOI: 10.1016/0005-2728(94)90235-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The plethora of microbial oxidases revealed by photochemical action spectra (Chance, B. (1989)) Biochim. Biophys. Acta 1000, 345-347) has led to detailed identification, purification and overproduction in many species, to the point where kinetic comparison of properties seems to allow structure/function deductions. This work compares the carbon monoxide recombination of five types of oxidases obtained from various organisms. The results are plotted in an Arrhenius-type plot and suggest that the carbon monoxide ligation is a sensitive indicator of the heme environment specific for an oxidase expressed under a given oxygen concentration. This survey of the carbon monoxide recombination kinetics of naturally occurring cytochrome oxidases in whole cells shows evidence for structural control of the reaction kinetics.
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217
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Seshadri TP, Skrzypczak-Jankun E, Yin M, Tulinsky A. Differences in the metal ion structure between Sr- and Ca-prothrombin fragment 1. Biochemistry 1994; 33:1087-92. [PMID: 8110739 DOI: 10.1021/bi00171a006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The structure of Sr-prothrombin fragment 1 has been solved and refined by restrained least-squares methods at 2.5-A resolution to a crystallographic R value of 0.167. The protein structure is very similar to that of Ca-fragment 1. A polymeric array of five Sr2+ ions separated by about 4.0 A is buried among six gamma-carboxyglutamic acid (Gla) residues; three other Sr2+ ions interact with other Gla residues and are located further apart. One of these was not found in the Ca-fragment 1 structure. The coordination of the Sr2+ ions resembles that of Ca2+, but there are some significant differences between them. The most notable is the lack of water coordination with Sr2+ ions and two conformations for Gla 8, which change the coordination of Sr-2 and Sr-3. A hexose moiety of an oligosaccharide was located in the vicinity of Asn101 that was flexibly disordered in Ca-fragment 1. The new Sr2+ ion found may be involved in metal ion phospholipid binding interactions along with Sr-1, and Sr-7, Sr-8.
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218
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Preisler HD, Banavali SD, Yin M, Venu G, Li YQ, Gaskins F, Raza A. Parallel studies of clonogenic leukaemia cells and the leukaemia cell population as a whole in acute myelogenous leukaemia. Eur J Cancer 1994; 30A:1511-6. [PMID: 7833110 DOI: 10.1016/0959-8049(94)00278-d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The clonogenic cells in patients with acute myelogenous leukaemia (AML) were evaluated with respect to the relationship between primary and secondary cloning capacity and the proliferative and molecular biological characteristics of the leukaemia cell population as a whole. Secondary cloning capacity was correlated with primary cloning efficiency, and with the ability of the clonogenic cells to produce large sized clones. The cloning capacity of AML cells was unrelated to the cell cycle characteristics of the leukaemia cell population in vivo or to the level of myc, myb, fms, or interleukin (IL)1 beta expression. The sensitivities of the clonogenic cells to cytosine arabinoside and daunorubicin were inversely correlated with the ability of the leukaemia cells to produce large sized clones in vitro. This latter observation may explain the reported relationships between the clonogenic capacity of AML cells and response to chemotherapy.
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219
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Daemen JW, Kootstra G, Wijnen RM, Yin M, Heineman E. Nonheart-beating donors: the Maastricht experience. CLINICAL TRANSPLANTS 1994:303-316. [PMID: 7547551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The growing gap between the number of organs available for transplantation and patients on waiting lists demands additional donor sources. Nonheart-beating (NHB)-donor programs are known to increase the number of kidneys available. The group of potential NHB donors is very diverse and therefore 4 categories have been identified. At the University Hospital Maastricht, a NHB-donor program was implemented in 1980 to harvest kidneys after an in situ perfusion technique. In order to evaluate the function of kidney grafts from NHB donors, a retrospective multicenter study on the NHB-donor kidneys transplanted until 1992 was performed, using a control group of kidneys from heart-beating (HB) donors. The short-term results showed more delayed function (DF) in the NHB-donor group accompanied by higher serum creatinine levels at one-month posttransplant. The long-term outcome, however, was equal in both groups showing similar graft and patient survival rates up to 5 years. Apart from the type of donor, HB or NHB, only the number of HLA-DR mismatches could be identified as a potential risk factor for delayed graft function. NHB donors contribute considerably to reducing the gap between offer and demand in kidney transplantation and transplant centers should include NHB donors in their procurement programs. Meanwhile, efforts should be made to improve the short-term posttransplant graft function. Together with reducing DF, searching for valuable tools in viability assessment should also be an objective. Past viability tests never found broad clinical use but might be important in the optimal and safe usage of the potential NHB donor pool.
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220
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Yin M, Lee CC, Ohta H, Talman WT. Hemodynamic effects elicited by stimulation of the nucleus tractus solitarii. Hypertension 1994; 23:I73-7. [PMID: 7904259 DOI: 10.1161/01.hyp.23.1_suppl.i73] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Microinjection of the excitatory amino acid L-glutamate into the nucleus tractus solitarii (NTS) elicits decreases in arterial pressure and heart rate. In the present study, we sought to determine the regional hemodynamic effects that were correlated with changes in arterial pressure and heart rate produced by stimulation of the NTS. In anesthetized rats, blood flow in the renal (RBF), superior mesenteric (MBF), and hindquarter (HBF) vascular beds was measured by pulsed Doppler flowmeters. Relative vascular resistances (RVR, MVR, and HVR) were calculated by dividing mean arterial pressure (mm Hg) by the Doppler shift (kHz). Microinjection of L-glutamate into the NTS caused rapid, transient, dose-related decreases in mean arterial pressure and heart rate. MVR and RVR were minimally changed immediately after injections, but both demonstrated delayed dilatation. In contrast, HVR fell immediately but demonstrated delayed constriction. Identical changes occurred in intact rats and in those with interruption of the baroreflex by sinoaortic denervation. Ganglionic blockade with hexamethonium abolished virtually all L-glutamate-induced responses. This study suggests that NTS neurons exert differential effects on renal, mesenteric, and hindquarter vascular beds and that glutamate-induced regional hemodynamic changes are mediated predominantly through autonomic pathways.
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221
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Booster MH, Yin M, Stubenitsky BM, Kemerink GJ, van Kroonenburgh MJ, Heidendal GA, Halders SG, Heineman E, Buurman WA, Wijnen RM. Beneficial effect of machine perfusion on the preservation of renal microcirculatory integrity in ischemically damaged kidneys. Transplant Proc 1993; 25:3012-6. [PMID: 8266433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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222
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Booster MH, Wijnen RM, Yin M, Tiebosch AT, Heineman E, Maessen JG, Buurman WA, Kurvers HA, Stubenitsky BM, Bonke H. Enhanced resistance to the effects of normothermic ischemia in kidneys using pulsatile machine perfusion. Transplant Proc 1993; 25:3006-11. [PMID: 8266432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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223
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Zhuang P, Yin M, Holland JC, Peterson CB, Howell EE. Artificial duplication of the R67 dihydrofolate reductase gene to create protein asymmetry. Effects on protein activity and folding. J Biol Chem 1993; 268:22672-9. [PMID: 8226776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
R67 dihydrofolate reductase (DHFR), encoded by an R plasmid, provides resistance to the antibacterial drug trimethoprim. This enzyme does not exhibit any structural or sequence homologies with chromosomal DHFR. A recent crystal structure of tetrameric R67 DHFR (D. Matthews, X. Nguyen-huu, and N. Narayana, personal communication) shows a single pore traversing the length of the molecule. Numerous physical and kinetic experiments suggest the pore is the active site. Since the center of the pore possesses exact 222 symmetry, mutagenesis of residues designed to explore substrate binding will probably also affect cofactor binding. As a first step in breaking this inevitable symmetry in R67 DHFR, the gene has been duplicated. The protein product, R67 DHFRdouble, is twice the molecular mass of native R67 DHFR and is fully active with kcat = 1.2 s-1, Km(NADPH) = 2.7 microM and Km(dihydrofolate) = 6.3 microM. Equilibrium unfolding studies in guanidine-HCl indicate R67 DHFRdouble is more stable than native R67 DHFR at physically reasonable protein concentrations. Microcalorimetry studies show native R67 DHFR undergoes fully reversible thermal unfolding. Unfolding can be described by a two-state process since a ratio of delta Hcalorimetric to delta Hvan't Hoff equals 0.96. In contrast, thermal unfolding of R67 DHFRdouble is not fully reversible and possesses an oligomerization component introduced by the gene duplication event.
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Zhuang P, Yin M, Holland J, Peterson C, Howell E. Artificial duplication of the R67 dihydrofolate reductase gene to create protein asymmetry. Effects on protein activity and folding. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)41580-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Qiu X, Yin M, Padmanabhan KP, Krstenansky JL, Tulinsky A. Structures of thrombin complexes with a designed and a natural exosite peptide inhibitor. J Biol Chem 1993; 268:20318-26. [PMID: 8376390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The structures of two hirudin-based fibrinogen recognition exosite peptide inhibitors with significantly different sequences complexed with alpha-thrombin at a site distinct from the active site (exosite) have been determined crystallographically at 2.2 and 2.3 A resolution. One is a designed synthetic peptide with some nonconventional amino acid residues (MDL-28050), and the other is a natural COOH-terminal peptide isolated from the leech Hirudinaria manillensis (hirullin P18). The structures have been refined by restrained least squares methods to R values of 0.161 and 0.155, respectively. The first stretch of each peptide, corresponding to hirudin 55-59, associates with thrombin similar to hirudin and hirugen (hirudin 53-64). Although the remaining residues of the inhibitors interact with and bind to thrombin, the binding is accomplished. through a rigid body conformational adjustment of the peptide with respect to the conformation displayed by hirudin and hirugen (40 degrees rotation about the Ile59, CA-C bond). This causes the side groups of cyclohexylalanine 64' of MDL-28050 and Ile60, of hirullin to point in the opposite direction of the all important Tyr63, ring of hirudin and hirugen but permits the residues to penetrate and interact with the 3(10) turn hydrophobic binding pocket of thrombin. Thus, the hydrophobic interaction is accomplished in a different way by virtue of the substrate conformational readjustment. The results show that the first stretch of peptide makes concerted and efficient binding interactions with thrombin, and the peptide positions of the inhibitors are fairly specific and homologous so that the stretch appears to be related to specific recognition associated with the exosite. The relative flexibility of structure and sequence of the second stretch is a display of tolerance of imprecision by thrombin in its COOH-terminal hydrophobic association with hirudin-based inhibitors.
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