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Biomedical subjects

J Zhu

Publications and source records attributed to J Zhu.

At least 541 records · Page 30Linked to original sources
PubMed1997

[Effects of EDRF on the vasoconstrictor action of phenylephrine in rat aorta].

The influence of endothelium-derived relaxing factor (EDRF) on the vasoconstrictor effect of phenylephrine on rings of rat aorta was studied in this paper. Rings of rat aorta, with or without endothelium, were suspended in organ chambers for the measurement of contractive force and contractive speed. All experiments were performed in the presence of indomethacin (10 mumol/L) to prevent the production of vasoactive prostanoids. When the preparations with intact endothelium were treated with methylene blue (10 mumol/L), an inhibitor of the target enzyme of EDRF, or NG-nitro-L-arginine (30 mumol/L), an inhibitor of EDRF formation, dose-contractive force curves of phenylephrine shifted to left: the EC30 value decreased 5-fold and the maximal response ratios were 1.6 +/- 0.4 and 1.6 +/- 0.5 (n = 8) respectively. These results were similar to those observed after mechanical removal of the endothelium: a 3-fold decrease in the EC30 value and the maximal response ratio was 1.0 +/- 0.2 (n = 8), The latter results may be related to a little EDRF produced by vascular smooth muscle. Our results suggest that the vasoconstrictive effect induced by phenylephrine may also be regulated by EDRF production from vascular endothelium and smooth muscle.

Animals↗
PubMed1997

[Reoperations on prosthetic heart valves: an analysis of 64 cases].

During the period of Fabruary 1988 to May 1996, 64 reoperations were performed for prosthetic valve malfunction. Degeneration of bioprosthesis occurred in 46 patients, failure of mechanical prosthesis in 9, and periprosthetic leakage without evidence of infection in 9. In accordance with the status of cardiac function, 9 patients with acute dysfunction of mechanical prosthesis received emergency operations, and the remaining 55 patients with bioprosthetic valve failure or periprosthetic leakage received selective operation. There were 8 early deaths with a overall hsopital mortality rate of 12.5%. Three of the deaths occurred among the 55 selective procedures for a mortality of 5.3% and 3 of the deaths occurred among the 9 emergence procedures for mortality of 33.3%. The 56 long-term survivors were followed up from 3 months to 7 years (mean 2.1 years). There were 3 late deaths (5.3%). Forty-eight patients have been living more than 1 year. Their cardiac function after reoperation was class I (42 patients), class II (5), and class III (1). The timing of reoperation and surgical technique were discussed.

Adult↗
PubMed1997

[Effect of phentolamine on portal pressure in cirrhotic patients with portal hypertension].

Changes of hepatic venous wedge pressure (WHVP) and portal venous pressure (PVP) in fourteen patients with postnecrotic cirrhosis proved pathologically and seven patients with colon carcinoma without hepatopathy were observed before and after the infusion of alpha-adrenergic receptor antagonist phentolamine from peripheral venous. The results indicate that phentolamine can reduce WHVP and PVP of cirrhotic patients with portal hypertension efficiently (0.56-0.63 kPa, 0.42-0.50 kPa, respectively, P < 0.01), but it effects arterial diastolic pressure and heart rate simultaneously (arterial diastolic pressure reduced by 0.94-10.7 kPa, while heart rate increased by 8.67-10.67 per minute). Phentolamine doec not reduce portal pressure on patients without portal hypertension.

Adrenergic alpha-Antagonists↗
PubMed1997

[Perioperative plasma amino acid spectrum analysis in portal hypertensive cirrhotic patients undergoing portacaval H-graft shunt].

Perioperative plasma amino acid spectrum (PAAS) was analysed in 10 portal hypertensive patients (PH) receiving portacaval H-graft shunt (D = 8 mm) and 10 gastroenteropathic patients (GE) without hepatic disease. In both groups, arterial, peripheral and hepatic venous blood was drawn for analysis immediately pre- and post-operation on the table, postoperative day 1 and 3, respectively. It was found that amino acid concentration decreased in both groups but in PH group it was changed significantly. The preoperative branched chain amino acid (BCAA)/aromatic amino acid (AAA) ratio was less than 2 in the PH group and larger than 3 in the GE group after operation. The ratio did not change significantly in both groups after operation. In the PH group, the pre- and post-operative BCAA and AAA level in hepatic vein was higher than in other sites. The immediately BCAA and AAA levels were lower than preoperative levels. Among the changes the postoperative decrease of VAL and LEU was significant. Both BCAA and AAA reached preoperative level at postoperative day3. The results reveal that small diameter portacaval shunt has no significant influence on PAAS. The temporary decrease of amino acid levels postoperatively may be related to the stress of operation and liver impairement.

Adult↗
PubMed1997

[The use of microwave for immunohistochemical technology in forensic pathology].

A microwave oven (MWO) of National brand was applied for Labeled Streptavidin Biotin immunohistochemical staining (LSAB method) on autopsy materials of 20 cases to detect 10 kinds of antigen of heart and brain: The keys to manipulate MWO as follows: (1) Recovery of antigen: submerge sections in 0.01M citrate buffer (pH 6.0), turn MWO to the position of DEF (210W) for 10 min, reaching temperature 92 degrees C-98 degrees C. (2) add normal serum, first antibody, second biotinylated antibody and streptavidin complex, then turn MWO to the position of LOW (70W) for 5 min, reaching temperature 20 degrees C-37 degrees C. Other steps were the same as the standards. Results showed: MWO can recover the destroyed or covered antigen, improve positive staining degree, reduce background's stain and shorten staining time.

Antigens↗
PubMed1997

[Maze procedure for chronic atrial fibrillation associated with mitral valve disease].

From May 1995 to October 1996, 20 patients with mitral valve disease underwent the maze procedure for chronic atrial fibrillation and mitral valve replacement or mitral valvuloplasty. Epicardial mapping data demonstrated that the large macrorecurre flutter circuit was located in left atrium (14/20) and complex fibrillation in right atrium (18/20) of the majority of patients. No early death occurred. 20 patients were followed up for at least 3 months (range 3-20 months) and 14 patients for at least 1 year after operation, sinus rhythm and atrioventricular synchrony were restored (100%), atrial fibrillation was not induced by electrophysiologic study. The right and left atrial transport function was preserved (100%) by Doppler echocardiogram tracings. One patient died from acute necrotic hepatitis, 4 and half months after operation. Cox maze procedure was modified, atrial flutter and atrial fibrillation never occurred. In this study, the electrophysiologic mechanism of chronic atrial fibrillation associated with mitral valve disease, indications of operation and clinical results are discussed.

Adult↗
PubMed1997

[The prognostic values of FCM determination of primary tumor and axillary lymph node of the patients with breast cancer].

Using Flow cytometry, we determined the ploidy and SPF on the primary tumor and axillary lymph node of 58 patients with breast cancer. Follow up for 5 years evealed that 23 patients had recurrence. 21 of them died. We conclude that the patients with aneuploid and high SPF have a higher relapce rate than those with diploid and low SPF, especially in those with advanced stage tumor or metastatic lymph node. It seems that ploidy and SPF of primary tumors affect more strong the prognosis of the patient than those of axillary lymph node. The probable cause of the recurrence of diploid tumor patients suggest post operation treatment for the patients with aneuploid cancer.

Adult↗
PubMed1997

[A preliminary study on the effect of estrogen on nasal mucosal hyperreactivity].

To understand the mechanism of the effect of estrogen on nasal mucosal hyperreactivity, animal models (guinea pigs) with different levels of estradiol (E2) were observed as follows: 1. effect of the change of E2 levels on E2 receptors (E2R) content in nasal mucosa; 2. effect of E2 level changes on histamine content in nasal mucosa and on nasal mucosal eosinophil and mast cell counts; 3. effect of E2 on release of cytokine IL-6 from macrophages. The results showed that high level of E2 might reduce the E2R content and eoinophil count but no significant effect on mast cells count and histamine content. The secretion of IL-6 from the macrophages was suppressed by E2 within concentration range of 3.13-50 micrograms/L. It was suggested that estradiol may play a complicated role in nasal mucosal hyperreactivity.

Animals↗
PubMed1997

[Correlation analysis of radiation effects on potential doubling time (Tpot) for human nasopharyngeal carcinoma cells].

OBJECTIVE: To understand radiation-induced cell kinetic changes of human nasopharyngeal carcinoma CNE cells and clarify cell biology basis of repopulation. METHODS: Either exponential growing stage or plateau stage human nasopharyngeal carcinoma CNE cells were measured by BrdUrd/DNA bivariate flow cytometry for phase fraction, BrdUrd labeling index, S phase duration, potential doubling time (Tpot), etc. Correlation analysis of Tpot with other kinetic parameters was made. RESULTS: (1) For exponentially growing CNE cells, shortening of Tpot after irradiation was closely correlated with increased BrdUrd labeled S phase fraction (P < 0.05), whereas no correlation was found between Tpot and other kinetic parameters measured; (2) for plateau stage CNE cells, shortening of Tpot with various radiation doses was closely correlated with decreased G0/G1 phase fraction (P < 0.05) and increased G2M phase fraction (P = 0.002), whereas no correlation was found between Tpot and other parameters measured. CONCLUSION: In a range of 0-8 Gy of irradiation, an increased accelerated repopulation rate was resulted from increasing radiation dose. Recruitment of G0 cells into cell cycle might play a major role in radiation-induced accelerated repopulation for plateau stage CNE cells, while it was contributed by an increased DNA synthesis manifested by an increased BrdUrd labeled S phase fraction for exponential growing CNE cells.

Cell Division↗
PubMed1997

The effects of monoamine reuptake inhibiting antidepressants in experimental allergic neuritis.

Experimental allergic neuritis (EAN) is a CD4+ T cell mediated autoimmune disease that is characterized by inflammation and demyelination affecting the peripheral nervous system (PNS). EAN represents an animal model for the study of the immunopathogenesis, immunoregulation and immunotherapy of human Guillain-Barré syndrome (GBS). Although the pathogenesis of EAN remains an enigma, growing evidence points to a possible involvement of an integrated attack by T cells, B cells and macrophages. Th1 related inflammatory cytokines like interferon-gamma (IFN-gamma), tumour necrosis factor-beta (TNF-beta) and TNF-alpha, IL-6 as well as IL-12 could play a major role in the development of tissue damage in EAN. The monoamine reuptake inhibiting antidepressants show immunomodulatory effects on clinical signs and immune response of EAN. The mechanisms behind the suppressive effect of zimeldine, norzimeldine, clomipramine and imipramine on EAN symptoms may include an action on T cell autoreactivities that are directed against myelin proteins. Suppression may be the net result of local accumulation of 5-HT and noradrenalin in regional lymph nodes and peripheral nerves as well as direct and indirect drug effects on cytokine release by peripheral lymphocytes. These antidepressant drugs also exert modulatory effects on MHC class I and II in EAN rat macrophages even in the absence of IFN-gamma. The modulatory effect of antidepressant drugs on IFN-gamma induced MHC class I and II expression may contribute to their influence on demyelinating autoimmune diseases, and may have implications for their clinical use.

Animals↗
PubMed1997

[Design of CA-1680 biochemical analyzer].

The paper provides the design idea structure of key parts software and hardware of microprocessor of CA-1680 Biochemical Analyzer. The instrument uses the specific flow cell high properties photodiode and programmable amplifier. The 16 bit programmable A/D conversion is completed with V/F convertor and programmable counter. Logarithm conversion is completed with software. On Using these methods, the instrument has not only simpler circuit, better reliability, but also the characteristics of accuracy, precision and widely linearity.

Biochemistry↗
PubMed1997

[The preparation of poly (DL-lactide) hollow fiber and the release of drug in vitro].

The biodegradable hollow fibers of DL-PLA were prepared by a dry-wet phase inversion spinning process. By using four different spinning systems, DL-PLA hollow fibers with varying asymmetric membrane structure were obtained. The structure of hollow fiber wall was examined by SEM. In vitro release of norethisterone from the DL-PLA hollow fibers was also investigated. The hollow fibers were filled with a 50 wt% NET in castor oil. The DL-PLA hollow fibers NET release was found to be dependent on the membrane structure of the hollow fiber wall. Possible release mechanisms were discussed.

Delayed-Action Preparations↗
PubMed1997

[Synthesis and antifungal activities of 1-(2-[(substituted-phenyl) methyl]thio)-2-(2,4-difluorophenyl)ethyl-1H-1,2,4-triazoles].

Twenty-one 1-[2-[[(substituted-phenyl) methyl] thio]-2-(2, 4-difluorophenyl) ethyl]-1H-1,2,4-triazoles were synthesized and 19 compounds are reported for the first time. Results of biological tests in vitro showed that the antifungal activities of all title compounds were better than or comparable to the activities of fluconazole. The antifungal activities of compounds 1-7 and 11-17 were better than or comparable to the activities of sulconazole. Compounds 1, 2 and 5 were 512 times more active than sulconazole against epidermophyton floccosum; compound 5 was 32 times more active against Candida albicans, compound 2 was 32 times more active against Sporotrichum schenckii; compounds 2 and 14 were shown to be 64 and 32 times more active against Cryptococcus neoformans; compounds 1 and 5 were 16 times more active against Aspergillus fumigatus.

Antifungal Agents↗
PubMed1997

[Comparative molecular field analysis (CoMFA) of allylamine antimycotics].

Active analog approach has been applied to determine the pharmacophoric conformations of the allylamine antimycotics. Comparative molecular field analysis (CoMFA) has been used to establish 3D-QSAR of 48 allylamine antimycotics against six common human pathogenic fungi. Two different alignment rules were compared in the meantime. Five new synthetic compounds have been successfully employed to examine the predictive abilities of the CoMFA models against Trichophyton mentagrophytes and Aspergillus fumigatus.

Allylamine↗
PubMed1997

[Preliminary studies on proliferation of hemorrhagic fever with renal syndrome virus in Leptotrombidium (L.) Scutellare].

In order to observe further the proliferation and kinetic changes of hemorrhagic fever with renal syndrome virus (HFRSV) in Leptotrombidium (L.) Scutellare infected with HFRSV, the raised Leptotrombidium (L.) Scutellare which were at larve stage or at nymph stage were grinded and sterilized by filtration at interval of 20 days, each batch of the filtrate was inoculated separately to Vero-E6 cells and the titre (TCID50/ml) of HFRSV was measured. The results confirmed: HFRSV were isolated from each batch of larve besides the batch at the 60th days, and the titre of HFRSV was -10(-1)-10(-4); HFRSV were also isolated from two batches of nymph. The isolated HFRSV were amplified by PCR technique and the HFRSV RNA were positive. The above results give rise to evidence that Leptotrombidium (L.) Scutellare might be the transmission vector of HFRSV.

Animals↗
PubMed1997

[Cloning and sequencing of nucleoprotein gene of Chinese rabies virus vaccine strain (5aG)].

Rabies virus 5aG strain (5aGRV) is used to produce primary hamster kidney tissue culture vaccine against Rabies in China. Nucleoprotein (NP), an important constituent of rabies virus, can intrigue Th cell and induce B cell to produce antibody. In order to study the molecular and biological characteristics of 5aG NP, we have cloned and sequenced the nucleoprotein gene. First, total RNA was extracted from infected mouse brain by Guanidine Isothiocyanate one-step method, then the first strand cDNA was synthesized by reverse transcription with oligo (dT) 18 as primer. After RACE (Rapid Amplification of cDNA Ends), one pair of oligonucleotide primers designed referring to the nucleoprotein gene of other strains, were used in PCR to amplify the fragments of nucleoprotein gene (1.4kb). When these fragments were inserted into vector pUC18, sequences of the nucleoprotein gene were obtained by double-stranded sequencing. Comparing the nucleic acid and deduced amino acid sequence of 5aGRV nucleoprotein gene with available NP sequences of other RV strains, we found that the nucleoprotein has less variation than glycoprotein, so nucleoprotein is more suitable to be used as a diagnostic reagent and a subunit vaccine.

Animals↗