551
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Thurman RG, Gao W, Connor HD, Adachi Y, Stachlewitz RF, Zhong Z, Knecht KT, Bradford BU, Mason RP, Lemasters JJ. Role of free radicals in failure of fatty livers following liver transplantation and alcoholic liver injury. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1996; 387:231-41. [PMID: 8794217 DOI: 10.1007/978-1-4757-9480-9_31] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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552
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Sidransky E, Fartasch M, Lee RE, Metlay LA, Abella S, Zimran A, Gao W, Elias PM, Ginns EI, Holleran WM. Epidermal abnormalities may distinguish type 2 from type 1 and type 3 of Gaucher disease. Pediatr Res 1996; 39:134-41. [PMID: 8825398 DOI: 10.1203/00006450-199601000-00020] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A major clinical challenge in Gaucher disease is the early and presymptomatic discrimination of type 2 (acute neuronopathic) from milder type 1 and type 3 Gaucher patients to enable appropriate management and counseling. Although most patients with Gaucher disease do not have skin abnormalities, a subset of patients with severe type 2 Gaucher disease display ichthyosiform skin. Analogous findings occur in the skin of type 2 (null allele) Gaucher mice. Ultrastructural and functional studies of epidermis from these mice reveal that glucocerebrosidase is required to generate functionally competent membranes for normal epidermal barrier function. We have extended our studies by examining the epidermal lipid content and ultrastructure in all three types of Gaucher patients. Only the type 2 Gaucher patients, some of whom had clinical ichthyosis, demonstrated an increased ratio of epidermal glucosylceramide to ceramide as well as extensive ultrastructural abnormalities, including the persistence of incompletely processed lamellar body-derived contents throughout the stratum corneum interstices. These epidermal alterations may provide a means for early differentiation of type 2 Gaucher disease.
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553
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Gao W, Li Z, Xiao P. [Preliminary study on physiology and biochemistry in Fritillaria thunbergii Miq. in the alternate process of new and old organs]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1995; 20:719-21, 762. [PMID: 8703333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The changes of weights, various sugars and diastase of the old scale and bud in Fritillaria thunbergii were studied in the alternate process of the new and old organs. The results showed that starch was finally disintegrated and inverted to sucrose before being transported to the new organ.
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554
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Zhong Z, Connor HD, Mason RP, Qu W, Gao W, Lemasters JJ, Thurman RG. Role of Kupffer cells in reperfusion injury in fat-loaded livers from ethanol-treated rats. J Pharmacol Exp Ther 1995; 275:1512-7. [PMID: 8531123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Reperfusion injury was studied in blood-free perfused livers from fat-loaded, ethanol-treated rats. Rats were pair-fed a modified Lieber-DeCarli liquid diet containing 36% calories as ethanol or isocaloric maltose-dextrin for 4 to 5 weeks. Reperfusion injury to the liver, which occurs in previously hypoxic regions upon reintroduction of oxygen, was studied in a low-flow, reflow perfusion model. Lactate dehydrogenase in effluent perfusate increased from basal levels of < 1 to 17 IU/g/h in livers from controls, whereas prior alcohol treatment elevated values to 37 IU/g/h. Pretreatment of rats with gadolinium chloride (GdCl3, 20 mg/kg i.v.), a selective Kupffer cell toxicant, minimized lactate dehydrogenase release during reperfusion to 7 to 8 IU/g/h in livers from both groups. Rates of malondialdehyde production were 144 and 166 nmol/g/h during reperfusion in control and alcohol-treated rats, respectively, but values reached only 54 and 79 nmol/g/h after GdCl3 treatment. Interestingly, a typical PBN/carbon-centered free radical adduct signal was detected in bile of livers from ethanol-treated rats, but not in controls or ethanol-treated rats given GdCl3. Portal pressure increased during the reperfusion period in livers from alcohol-treated rats, although not in controls, and GdCl3 reduced it significantly. Taken together, these data indicate that reperfusion injury is greater in fatty livers from alcohol-treated rats in a blood-free model. Inactivation of Kupffer cells minimized reperfusion injury in both control and alcohol-treated rats, most likely by diminishing lipid peroxidation thereby improving hepatic microcirculation.
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555
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Guo Z, Gao W, He L. [The effect of different topical agents on pseudomonas infection of burn wound]. 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 1995; 11:421-4. [PMID: 8728928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
48 Wistar rats were scalded resulting in 15% TBSA full-thickness burn. Pseudomonas aeruginosa (10(9)/ml was inoculated to the wounds. The rats were divided into 6 groups. 5 different topical agents were separately applied to the wounds constituting 5 groups, and no drug was used in control group. Through observing the appearance of wound, the quantity of bacteria in the subeschar tissue and histo-pathological changes, we confirmed that AgSD-ZnSD-A cream was a satisfactory topical agent.
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556
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Lemasters JJ, Peng XX, Bachmann S, Currin RT, Gao W, Thurman RG. Dual role of Kupffer cell activation and endothelial cell damage in reperfusion injury to livers stored for transplantation surgery. J Gastroenterol Hepatol 1995; 10 Suppl 1:S84-7. [PMID: 8589353 DOI: 10.1111/j.1440-1746.1995.tb01808.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In rat models of liver preservation, the primary event leading to liver graft failure after cold storage is a reperfusion injury causing damage to sinusoidal endothelial cells and activation of Kupffer cells (KC). After storage for longer than 16 h in University of Wisconsin solution, reperfusion induces rapid endothelial cell killing. Kupffer cell activation also occurs as indicated by cell surface ruffling, degranulation, release of hydrolytic enzymes, generation of oxygen radicals, and increased phagocytosis. Down-regulation of KC activity with nisoldipine or pentoxifylline improves graft survival. Moreover, pretreatment of donors with small amounts of endotoxin to activate KC causes a drastic reduction of graft survival. Together, KC activation and endothelial damage cause marked microcirculatory disturbances after transplantation characterized by reduced and uneven blood flow and increased leucocyte and platelet adhesion. Such events culminate in inflammation, necrosis and fulminant graft failure. Modification of reperfusion conditions can reduce the extent of injury. In particular, flushing livers with Carolina rinse solution (CRS) at the end of storage reduces endothelial cell killing, suppresses KC activation, improves the microcirculation, and increases graft survival. Active ingredients in CRS include antioxidants (allopurinol, desferrioxamine and glutathione), adenosine and slightly acidic pH (6.5). Other potentially important ingredients are nicardipine, a calcium channel blocker, and fructose, glucose and insulin to promote glycolysis. The cytoprotective amino acid, glycine, further improves the performance of Carolina rinse solution. Reperfusion-induced changes to nonparenchymal cells play an essential role in damage to livers preserved for transplantation surgery. Understanding the role of sinusoidal endothelial cells and KC in this injury has led to promising new strategies to prolong organ storage and reduce graft failure.
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557
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Thurman RG, Gao W, Connor HD, Adachi Y, Stachlewitz RF, Zhong Z, Knecht KT, Bradford BU, Mason RP, Lemasters JJ. Role of Kupffer cells in failure of fatty livers following liver transplantation and alcoholic liver injury. J Gastroenterol Hepatol 1995; 10 Suppl 1:S24-30. [PMID: 8589336 DOI: 10.1111/j.1440-1746.1995.tb01791.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Kupffer cells have been implicated in mechanisms of pathophysiology following liver transplantation. Recently, postoperative injury in ethanol-induced fatty liver has been evaluated because fatty livers often fail following transplantation. The low-flow, reflow liver perfusion model was used to study the role of Kupffer cells (KC) in reperfusion injury to fatty livers from rats fed a diet containing ethanol for 4-5 weeks. Treatment with GdCl3, which selectively destroys KC, decreased cell death significantly. Thus, destruction of KC minimized hepatic reperfusion injury, most likely by inhibiting free radical formation and improving microcirculation. Since it was demonstrated recently that destruction of KC prevented the hypermetabolic state observed with acute alcohol exposure, their involvement in events leading to alcohol-induced liver disease was investigated. In rats exposed to ethanol continuously via intragastric feeding for up to 4 weeks, GdCl3 treatment prevented elevation of aspartate aminotransferase (AST) and dramatically reduced the average hepatic pathological score. These results indicate that KC participate in the early phases of alcohol-induced liver injury. Endotoxaemia occurs in alcoholics and activates KC; therefore, we evaluated the effect of minimizing bacterial endotoxin by intestinal sterilization with the antibiotics polymyxin B and neomycin. Antibiotics diminished plasma endotoxin levels significantly and prevented ethanol-induced increases in AST values. These results indicate that endotoxin is involved in the mechanism of ethanol-induced liver injury. A six-line radical spectrum was detected with electron paramagnetic resonance spectroscopy in bile from alcohol-treated rats which was blocked by GdCl3. The free radical adducts had hyperfine coupling constants characteristic of lipid-derived free radical products. In conclusion, these studies demonstrate that KC are involved in reperfusion injury to ethanol-induced fatty livers and hepatic injury due to long-term treatment with ethanol.
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558
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Gao W, Jakubowski H, Goldman E. Evidence that uncharged tRNA can inhibit a programmed translational frameshift in Escherichia coli. J Mol Biol 1995; 251:210-6. [PMID: 7643397 DOI: 10.1006/jmbi.1995.0428] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In the modified release factor 2 (RF2) programmed translational frameshift (with a sense codon replacing the wild-type in-frame UGA codon at the shift site), ribosomes shift +1 into the reading frame for an out-of-frame reporter fused to the frameshift sequence. Partitioning of ribosomes between the out-of-frame shift and in-frame reading depends on the codon at the shift site and on the levels of tRNA decoding the in-frame codon. Overexpression of a tRNA species cognate to the in-frame codon at the shift site significantly reduces the frequency of frame-shifting, presumably by facilitating in-frame reading, which would reduce production of the out-of-frame reporter. However, since overexpression of a tRNA increases levels of both charged and uncharged tRNA, it is possible that uncharged cognate tRNA might be able to reduce the frequency of the frameshift, by entering the A site on the ribosome. To test this, we manipulated charged and uncharged tRNA levels in vivo, using the tryptophan analog tryptophan hydroxamate, which increases the proportion of uncharged tRNA(Trp) by competing with cognate amino acid tryptophan for tryptophanyl-tRNA synthetase, thereby reducing protein synthesis. We report here that a slight but reproducible reduction in the relative frequency of the frameshift is observed when tryptophan hydroxamate is added to cells containing the modified RF2 shift with UGG (Trp codon) at the shift site. When tRNA(Trp) is overexpressed from another plasmid, the shift frequency drops three- to fourfold, as expected, however, this reduction is still seen in the presence of the analog. Thus, under conditions when most of the tRNA(Trp) is apparently uncharged, excess tRNA(Trp) still causes a significant reduction in the frameshift when UGG is at the shift site, providing evidence that uncharged cognate tRNA also can inhibit this frameshift.
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559
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Guo Z, Sheng Z, Gao W. [Escharectomy during burn shock stage contributed to controlling or alleviating infectious complication]. ZHONGHUA WAI KE ZA ZHI [CHINESE JOURNAL OF SURGERY] 1995; 33:406-8. [PMID: 8565728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Among 29 patients with extensive burn, 14 received escharectomy during the shock period, and the other 15 after 96 hrs. LPS and TNF were determined before and after escharectomy 3, 7, 14 and 21 PBD. Incidence of sepsis and subeschar bacterial count were analyzed. Clinical conditions were compared. The results showed that escharectomy during burn shock stage significantly reduced infectious complications in extensively burned patients. We believe that as long as general condition of the patient allowed, early removal of eschar was beneficial in reducing the threat of sepsis.
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560
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Guo Z, Sheng Z, Diao L, Gao W, Yang H, Lin H, Han J. Extensive wound excision in shock stage in patients with major burns. Chin Med J (Engl) 1995; 108:273-7. [PMID: 7789215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
To stop excessive plasma loss, alleviate noxious effects of devitalized tissues on the body and shorten the hospitalization time, we performed extensive escharectomy during the shock period in extensively burned patients. Group A consisted of 21 patients aged 9-45 years (26.1 +/- 7.9 years), with a mean total burn area of 63.2% +/- 18.1% TBSA, and full-thickness injury involving 35.9% +/- 19.6% TBSA. The first escharectomy was done at 24.1 +/- 13.9 hours postburn, and excision area averaged 32.3% +/- 6.7% TBSA (24%-46%). In 15 of them, Swan-Ganz catheter was introduced to monitor the hemodynamic changes. It was found that RAP, PAP, PAWP, ABP, HR, CO and CI were all stable during and after the operation. Group B consisted of 29 patients aged 11-50 years (30.4 +/- 11.7 years), in whom escharectomy was begun 4-5 days postburn. The mean healing time of the patients in group A was 33.1 days, shorter than that of group B patients (40.1 days). The duration of hemoconcentration was shorter in group A. The amount of blood transfusion was almost 700 ml less in group A during the first two weeks. Less antibiotics were used with fewer visceral complications in group A. We believe that escharectomy during the burn shock stage is feasible.
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561
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Gao W, Connor HD, Lemasters JJ, Mason RP, Thurman RG. Primary nonfunction of fatty livers produced by alcohol is associated with a new, antioxidant-insensitive free radical species. Transplantation 1995; 59:674-9. [PMID: 7886790 DOI: 10.1097/00007890-199503150-00005] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The formation of free radicals after orthotopic liver transplantation in the rat correlates with graft failure. Fatty livers from alcoholics transplant poorly, so these studies were designed to examine the effect of alcohol on free radical formation in a rearterialized rat liver transplantation model. Treatment of rats for 3-5 weeks with either a high-fat or an ethanol-containing liquid diet caused characteristic pericentral lipid accumulation. After storage in University of Wisconsin cold storage solution (UW) and transplantation, a reperfusion injury characterized by increased postoperative AST levels (greater than 1500 U/l in about 3 hours) was observed in rats fed high-fat or alcohol-containing diets, whereas parenchymal cell injury was seen much less in low-fat controls. Survival was around 63% in the low-fat group but decreased to 12 and 18% in the high-fat and alcohol groups, respectively. Furthermore, intracellular lipid content correlated inversely with survival. In untransplanted livers, the spin trap alpha-phenyl N-tert-butylnitrone (PBN) was infused, and blood samples were collected and extracted with chloroform:methanol. Signals indicative of carbon-centered PBN radical adducts were barely detectable in all untransplanted groups studied by electron paramagnetic resonance. In contrast, a robust 6-line complex spectrum was obtained from all groups studied immediately after 48 hours of cold storage in UW solution and transplantation. A mixture of 3 radical species was identified. Two had coupling constants similar to lipid-derived free radicals, whereas the third is a new species with unique coupling constants and is most likely oxygen derived. In low-fat controls, the signal was reduced significantly by superoxide dismutase (SOD)/catalase; however, SOD/catalase had no effect on free radicals in lipid-loaded livers. Thus, both dietary high fat and alcohol exposure produce a unique SOD/catalase-insensitive free radical species that may be involved in the mechanism of failure of fatty livers after orthotopic liver transplantation.
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562
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Liu M, Gao W, Huo Y. [Percutanous transluminal coronary angioplasty for unstable angina]. ZHONGHUA NEI KE ZA ZHI 1995; 34:169-72. [PMID: 7648937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Percutanous transluminal coronary angioplasty (PTCA) was performed in 190 patients with 250 diseased vessels and 278 lesions from Dec. 1987 to Feb. 1994. All the patients had unstable angina (UA). There were 52 (18.7%) type A lesions, 175 (62.9%) type B lesions and 51 (18.3%) type C lesions. Of the 190 patients undergoing PTCA, 134 (70.5%) patients had dilatation of a single vessel, 46 (24.2%) of two vessels and 10 (5.3%) of three or more vessels. In 121 patients with multivessel disease, 98 (81.0%) had incomplete revascularization of the ischemia-related vessel (the culprit vessel) and only 23 (19.0%) had complete vessel revascularization. Kissing balloon technique was used in six patients and autoperfusion balloon in five. There were four patients undergoing directional coronary atherectomy (DCA) and four intracoronary stent. The clinical (patient) success rate was 94.7% (180/190) and technical (vessel) success rate 95.2% (238/250). The average degree of vessel stenosis was 88.7% +/- 8.3% before PTCA and the residual tenosis was 17.9% +/- 9.2% after PTCA. Acute vascular complications occurred in 18 (6.5%) lesions. 15 were managed successfully, two developed Q wave myocardial infarct and one died. None needed emergency coronary bypass operation. PTCA was not successful in 10 patients. In 180 patients with successful PTCA, 165 (91.7%) were free from UA, 15 (8.3%) patients had symptoms improved and oxygen need reduced. During a six-month follow-up, 26 patients had chest pain again with confirmed restenosis, repeated PTCA was performed successfully.
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563
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Gao W, Din J, Jin F. [The result of re-resection of lung cancer]. ZHONGHUA ZHONG LIU ZA ZHI [CHINESE JOURNAL OF ONCOLOGY] 1995; 17:30-2. [PMID: 7656783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In 38 cases of primary lung cancer with post-operative recurrence and metastasis or second primary lung cancer, re-resection was performed. The time interval between the first operation and re-resection was 2 months-9 years. The resectibility rate was 89.5%. Postoperative complication rate was 23.7% and the operative mortality rate within 1 months was 5.3%. With radical re-resection the one, three and five year-survival rate were 80%, 45.8% and 35% respectively. The survival time depends more on the thoroughness of resection than on the histologic type of the tumor and the time interval. It is of the opinion that wherever recurrence and/or metastasis occur. Radical reresection is the treatment of choice.
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564
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Gao W. Parameterization of subgrid-scale land surface fluxes with emphasis on distributing mean atmospheric forcing and using satellite-derived vegetation index. ACTA ACUST UNITED AC 1995. [DOI: 10.1029/95jd01464] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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565
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Adachi Y, Moore LE, Bradford BU, Gao W, Thurman RG. Antibiotics prevent liver injury in rats following long-term exposure to ethanol. Gastroenterology 1995; 108:218-24. [PMID: 7806045 DOI: 10.1016/0016-5085(95)90027-6] [Citation(s) in RCA: 491] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND/AIMS Kupffer's cells participate in alcohol-induced liver injury, and endotoxemia is observed in human alcoholics and in a rat model. This study evaluated the effect of reducing bacterial endotoxin production by intestinal sterilization on alcohol-induced liver injury. METHODS Male Wistar rats were exposed to ethanol continuously for up to 3 weeks via intragastric feeding. The gut was sterilized with polymyxin B and neomycin. RESULTS Fecal culture of stool samples from ethanol-fed rats treated with antibiotics showed virtually no growth of gram-negative bacteria. Endotoxin levels of 80-90 pg/mL in plasma of ethanol-fed rats were reduced to < 25 pg/mL by antibiotics. Antibiotic treatment also completely prevented elevated aspartate aminotransferase levels and significantly reduced the average hepatic pathological score in rats exposed to ethanol. Oxygen tension on the surface of the liver measured in vivo was decreased significantly from control values of 48 +/- 1 to 39 +/- 1 mumol/L in ethanol-treated rats. This hypoxia was prevented by treatment with antibiotics. Moreover, the increase in rates of ethanol elimination due to long-term ethanol treatment was prevented by antibiotic treatment. CONCLUSIONS Intestinal sterilization prevented alcohol-induced liver injury in the rat, supporting the idea that hypermetabolism and consequent hypoxia caused by activation of Kupffer's cells by endotoxin is involved in the mechanism.
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566
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Gao W, Feddes J, Robinson F, Cook H. Effect of Stocking Density on the Incidence of Usage of Enrichment Devices by White Leghorn Hens. J APPL POULTRY RES 1994. [DOI: 10.1093/japr/3.4.336] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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567
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Lau KW, Ding ZP, Gao W, Susan Q, Abdullah J. Pseudo-dissection in percutaneous transluminal coronary angioplasty. THE JOURNAL OF INVASIVE CARDIOLOGY 1994; 6:296-9. [PMID: 10155086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Percutaneous transluminal coronary angioplasty (PTCA) is a well-established and effective treatment modality for significant coronary artery disease. Because it enlarges the arterial lumen by plaque disruption, minor wall dissection is not infrequent. Complex dissections are, however, uncommon but may lead to acute vessel closure with its attendant major clinical morbidity and mortality. We describe here a case of pseudo-dissection and its potential for misinterpretation and subsequent inappropriate management.
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568
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Gao W, Goldman E, Jakubowski H. Role of carboxy-terminal region in proofreading function of methionyl-tRNA synthetase in Escherichia coli. Biochemistry 1994; 33:11528-35. [PMID: 7918366 DOI: 10.1021/bi00204a015] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The synthetic and editing functions of three forms of Escherichia coli methionyl-tRNA synthetase with different C-terminal sequences have been compared in vivo and in vitro. These forms include a full-length wild-type dimer (MRS676), a truncated monomer (MRS547) believed to be equivalent to the biologically active large tryptic fragment, and a third form denoted MRS581*. DNA sequencing revealed that MRS581* is predicted to contain 18 additional amino acids from the wild-type full-length sequence at the carboxy terminus of truncated form MRS547, and this is then fused to an additional 16 amino acids encoded by vector pBR322. Both MRS676 and MRS581* were found to edit endogenous homocysteine about 20-fold more efficiently than MRS547 in vivo. However, the three methionyl-tRNA synthetases edited exogenously supplied homocysteine in bacterial cultures to similar extents. Purified proteins exhibited no significant differences in editing function in vitro. Synthetic activity of purified MRS676 in vitro was found to be about 2.5-fold higher per subunit compared to the shorter forms of the enzyme. The C-terminal region in E. coli methionyl-tRNA synthetase is thus suggested to play an important role in editing in vivo, most likely by allowing interaction of the enzyme with the methionine biosynthetic pathway. These data support a model of channeling of at least some metabolites in bacterial protein synthesis.
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569
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Adachi Y, Bradford BU, Gao W, Bojes HK, Thurman RG. Inactivation of Kupffer cells prevents early alcohol-induced liver injury. Hepatology 1994. [PMID: 8045507 DOI: 10.1002/hep.1840200227] [Citation(s) in RCA: 284] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
It is well recognized that consumption of alcohol leads to liver disease in a dose-dependent manner; however, the exact mechanisms remain unclear. Hypoxia subsequent to a hypermetabolic state may be involved; therefore, when it was observed recently that inactivation of Kupffer cells prevented stimulation of hepatic oxygen uptake by alcohol, the idea that Kupffer cells participate in early events that ultimately lead to alcohol-induced liver disease became a real possibility. The purpose of this study was to test that hypothesis. Male Wistar rats were exposed to ethanol continuously by means of intragastric feeding for up to 4 weeks using the model developed by Tsukamoto and French. In this model, ethanol causes fatty liver, necrosis and inflammation--changes characteristic of alcohol-induced liver disease in human beings. Kupffer cells were inactivated by twice weekly treatment with gadolinium chloride (GdCl3), a selective Kupffer cell toxicant. AST levels were elevated to 192 +/- 13 and 244 +/- 56 IU/L in rats exposed to ethanol for 2 and 4 wk, respectively (control value, 88 +/- 7). This injury was prevented almost completely by GdCl3 treatment. Fatty changes, inflammation and necrosis were also all reduced dramatically by GdCl3 treatment. The average hepatic pathological score of rats treated with ethanol for 4 wk was 4.3 +/- 0.6, which was reduced significantly in ethanol- and GdCl3-treated rats to 1.8 +/- 0.5 (p < 0.05). Rates of ethanol elimination were elevated 2- to 3-fold in rats exposed to ethanol for 2 to 4 wk. This elevation was blocked by GdCl3 treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
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570
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Gao W, Wesely ML. Numerical Modeling of the Turbulent Fluxes of Chemically Reactive Trace Gases in the Atmospheric Boundary Layer. ACTA ACUST UNITED AC 1994. [DOI: 10.1175/1520-0450(1994)033<0835:nmottf>2.0.co;2] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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571
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Gao W, Ling J, Zhong X, Liu W, Zhang R, Yang H, Cao H, Zhang Z. Luffin-S--a small novel ribosome-inactivating protein from Luffa cylindrica. Characterization and mechanism studies. FEBS Lett 1994; 347:257-60. [PMID: 8034014 DOI: 10.1016/0014-5793(94)00554-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We purified and characterized a novel RIP (ribosome inactivating protein), Luffin-S from the seeds of Luffa cylindrica. Different from Luffin-A and B, which are RNA N-glycosidases with molecular weights of 27 and 28 kDa, respectively, Luffin-S has an M.W. of only approx. 10 kDa, much smaller than any other RIPs so far investigated. Its abundant resources, toxicity similar to TCS in a cell-free protein synthesis system and unique mechanism as phosphodiesterase, like alpha-sarcin, promisingly make it a potential toxic moiety of immunotoxin.
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572
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Connor HD, Gao W, Mason RP, Thurman RG. New reactive oxidizing species causes formation of carbon-centered radical adducts in organic extracts of blood following liver transplantation. Free Radic Biol Med 1994; 16:871-5. [PMID: 8070695 DOI: 10.1016/0891-5849(94)90207-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
alpha-(4-pyridyl-1-oxide)-N-t-butylnitrone (4-POBN) radical adducts from Folch (chloroform:methanol) extraction of blood of transplanted livers exhibited a large 6-line electron paramagnetic resonance (EPR) spectrum. Slow EPR sample preparation involving freezing and thawing prior to extraction over 15 min yielded a spectrum assigned as a lipid-derived free radical species, whereas rapid (< 1 min) extraction without a freeze-thaw cycle yielded a mixture of radicals, one with coupling constants similar to the alpha-hydroxymethyl-4-POBN adduct (4-POBN/.CH2OH). Extraction with purified chloroform, however, yielded a much weaker, probably lipid-derived signal. Use of 13C-methanol in the Folch extracting solution yielded a 12-line EPR spectrum, indicating that a new, highly reactive oxidant species from blood following liver transplantation can convert organic solvents used in tissue extractions to free radicals. This hypothesis was supported by simulation of EPR spectra of free radicals extracted rapidly with Folch, which indicated that the spectrum contained two carbon-centered species, one with hyperfine coupling constants similar to the alpha-methylhydroxyl-4-POBN adduct, the other probably lipid-derived. Because the former originates from methanol in the Folch, extraction of samples with alcohol-free organic solvent is most likely superior when the potential for formation of stable oxidant species exists, such as after liver transplantation.
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573
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Zhu GY, Gao W, Huo Y, Feng DL, Wang LH. Percutaneous transluminal coronary angioplasty. Its success rate and affecting factors. Chin Med J (Engl) 1994; 107:355-9. [PMID: 7924576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
From December 1987 to October 1983, percutaneous transluminal coronary angioplasty (PTCA) was performed in 302 patients with 392 diseased vessels and 440 lesions. The success rate was 93.71% in 302 patients, 94.90% in 392 diseased vessels and 95.00% in 440 lesions. The success rate was 98.92% in Type A lesion, 95.71% in Type B lesion, and 86.57% in Type C lesion (A vs B P = NS, A vs C P < 0.01). There were 55 lesions with total or subtotal occlusion, the success rate was 89.09% (93.10% in Type B lesion and 84.62% in Type C lesion). As to the diseased vessels, the success rate was 95.65% in LAD, 94.38% in LCX and 93.75% in RCA. The results showed no significant difference. In this series, acute ischemic complications were found in 6.59% (29/440). Of these 29 lesions, 23 were treated successfully, 5 developed Q wave myocardial infarction and 1 died.
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574
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Behboo R, Carroll PB, Ukah F, Gao W, Kirsch D, Dedousis N, Phipps J, Ricordi C. One-hour of hypothermic incubation in Euro-Collins improves islet purification. Transplant Proc 1994; 26:645. [PMID: 7513460] [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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575
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Gao W. Atmosphere-biosphere exchange flux of carbon dioxide in a tallgrass prairie modeled with satellite spectral data. ACTA ACUST UNITED AC 1994. [DOI: 10.1029/93jd03039] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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