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Biomedical subjects

Z Guo

Publications and source records attributed to Z Guo.

At least 325 records · Page 18Linked to original sources
PubMed1997

[The effect of calcium content in bovine cancellous bone as carrier on expression of tumor necrosis factor-alpha gene in mice].

We investigated the expression of tumor necrosis factor-alpha (TNF alpha) gene in the area of implanted calf cancellous bone with different calcium content and the influence of calcium salts on local cellular immunity. The particles of mineralized and partially demineralized bone were implanted in the mouse's muscle pouch, and removed 3, 5, 10 and 20 days after implantation of the bone particles. The specimens were processed for determining the expression of mRNA encoding TNF alpha, which was performed by a nonradioactive in situ hybridization technique. The expression of TNF alpha mRNA was markedly higher in the mineralized bone group than in the partially demineralized bone group (P < 0.01). The positive rate of TNF alpha gene expression was highest by 10 days after implantation. There was a strong hybridization signal localization to the cytoplasm of morphologically identifiable monocytes and multinucleated giant cells. Similar activity was detected in the cytoplasm or nuclei of mesenchymal cells, fibroblasts as well as striated muscle fibers. This finding suggests that the calcium content in calf cancellous bone possesses a significantly stimulative effect on TNF alpha mRNA expression, and calcium salts may be of importance for the modulation of local cellular immunity.

Animals↗
PubMed1997

[An experimental study on tissue renin-angiotensin-aldosterone system].

Aldosterone biosynthesis in kidney has been proved by means of kidney perfusion in vitro, high performance liquid chromatography, radioimmunoassay and TR-PCR, indicating that aldosterone biosynthesis is possible in tissues other than adrenal. Bilateral nephrectomy was carried out in male Wistar rats and the plasma renin activity would disappear after 30 hours. However, RT-PCR showed that the vasculature in the nephrectomized rats was still able to express renin mRNA. It means that the vasculature is different from the heart which depends on taking up renin from the circulation, while the vasculature takes renin produced locally in its own tissue to initiate the renin-angiotensin-aldosterone system. Perindopril, an angiotensin converting enzyme inhibitor (ACEI), inhibits not only the production of angiotensin II, but also the synthesis of aldosterone in the vasculature. ACEI reversion of vascular remodeling is probably related with its inhibition of aldosterone synthesis in the vasculature.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

Acupuncture methods for hemiplegic spasm.

Remitting hemiplegic spasticity in apoplexy (HSA) is an important problem in today's clinical study. Through teaching and clinical practice, the authors summed up the effective acupuncture methods for remitting HSA: puncture deeply the acupoints on the superior-spasm side (SSS) by filiform needles so as to obtain the intensive needling sensations in the deep tissues (ISDT) until the superior spasm is immediately remitted; tap the skin on the inferior-spasm side (ISS) by skin needles until the corresponding muscle contracts. The methods have showed a significant immediate and long-term therapeutic effect.

Acupuncture Therapy↗
PubMed1997

[Changes in contents of Zn, Cu, Fe, Ca, Mg in serum, urine and blister fluid after burn injury].

106 burned patients were divided into two groups: group L consisted of 57 patients with burns larger than 30% TBSA, and group S consisted of 49 patients with burns smaller than 30% TBSA. The contents of Zn, Cu, Fe, Ca, Mg in serum, urine and blister fluid were determined on 1, 2, 3, 7, 14, 21, 28 days after burn injury. The results indicated that all of the elements in serum were decreased except serum Fe on first day, and the levels were much lower in group L than in group S. The contents of Zn, Cu, Fe in urine were increased significantly and Ca, Mg in urine decreased. The contents of Zn, Fe, Ca in blister fluid were similar to normal values of serum, and Cu, Mg in blister fluid were less than that of serum. The studies indicated that the decrease in contents of Zn, Cu, Fe, Ca, Mg after burn injury was propably related to loss of these elements from urine and wound.

Adolescent↗
PubMed1997

[Effects of calcium channel blockers and calmodulin inhibitors on the secretion of endothelin-1 in cultured endothelial cells].

OBJECTIVE: The study is to investigate the effects of calcium channel blockers and calmodulin inhibitors on the secretion of endothelin-1 (ET-1) in cultured endothelial cells from human umbilical veins. RESULTS: Results showed that calcium channel blockers verapamil (5.5 x 10(-6) mol/L, 5.5 x 10(-5) mol/L), diltiazen (2.4 x 10(-4) mol/L) and calmodulin inhibitors chlorpromazine (3.1 x 10(-5) mol/L, 3.1 x 10(-4) mol/L), berbamine (1.6 x 10(-5) mol/L, 1.6 x 10(-4) mol/L) significantly decreased medium ET-1 levels in cultured endothelial cells. CONCLUSION: It was also indicated that extracellular calcium influx and calmodulin activity were necessary to the secretion of ET-1. In addition, nitroglycerine (2.2 x 10(-3) mol/L) remarkably reduced medium ET-1 levels in cultured endothelial cells, which suggested that nitric oxide might inhibit the secretion of ET-1.

Alkaloids↗
PubMed1997

[Further clinical analysis on the prognosis of chronic lymphocytic thyroiditis].

OBJECTIVE AND METHODS: There have been many reports on the incidence of hypothyroidism and thyroid carcinoma in chronic lymphocytic thyroiditis patients, however, the incidence of thyroid carcinoma had been a widely debated issue. Therefore 300 cases of chronic lymphocytic thyroiditis from 1964 to 1995 were reviewed. There were 37 males and 263 females, and 52 had a pathological diagnosis of chronic lymphocytic thyroiditis. RESULTS: Among 300 patients, 2 had coexistent thyroid papillary carcinoma. The original symptom in 64.3% patients was hypothyroidism, and the total incidence of hypothyroidism was 76%. It was also indicated in this study that the occurrence of hypothyroidism in chronic lymphocytic thyroiditis patient was associated with the elevated level of antithyroglobulin antibody, enlargement and tenderness of thyroid gland. CONCLUSION: In our study, as the low incidence of coexisted thyroid carcinoma, with the high incidence of hypothyroidism it seemed to be that the elevated antithyroglobulin antibody could be a more effective factor in the development of hypothyroidism in chronic lymphocytic thyroiditis.

Adolescent↗
PubMed1997

[Partial deletion of mitochondrial DNA in mitochondrial encephalomyopathies].

OBJECTIVE: To characterize the deletions of mitochondrial DNA (mtDNA) in Chinese patients with Kearns-Sayre syndrome (KSS) and chronic progressive external ophthalmolegia (CPEO) and identify deletion mutations of mtDNA be the etiology of these diseases. METHODS: Patients and preparation of total DNA: Two patients with KSS and two with CPEO and ten with other mitochondrial myopathies or encephalomyopathies were determined by histological and biochemical assays. Total DNA was isolated from 100 mg to 150 mg of frozen muscle obtained by biopsy using the methods described by Zeviani et al. (1988). Preparation of mtDNA probes: MtDNA were isolated and purified according to Palva's method (1985). The mtDNA was linearized by digestion with the restriction endonuclease Pvu II and separated by electrophoresis through low melting agarose gel. The 16.5 kb DNA band was recovered from the gel and labeled with alpha-p32 dCTP by random primer labeling. Southern blot analysis: Portions of five micrograms total DNA obtained from the patients and controls were digested with Pvu II, EcoR I, Hind III And Xba I respectively. The digested DNA was separated by agarose gel electrophoresis and transferred to nitrocellulose membrane and then hybridized with P32 labeled mtDNA as previously described (Zhang, 1991). RESULTS: A large-scale deletions of mtDNA were identified in two patients with KSS and two patients with CEPO. The deletions ranged in size from 2.4 kb to 5.5 kb. The proportion of mutated mtDNA in each patients ranged from 54.6% to 84.6% of total mtDNA. No detectable deletions were found in mtDNA of ten patients with other mitochondrial myopathies or encepholomyopathies and normal controls. CONCLUSIONS: Deletions of mtDNA were found in all KSS and CEPO patients detected. These results supported The view point of the deletions are important causes of physical defect in KSS and CEPO.

DNA, Mitochondrial↗
PubMed1997

[Clinical analysis of bilateral neck dissection in patients with laryngeal cancer].

The clinical materials of 54 cases with laryngeal cancer treated between 1980 and 1995 were retrospectively analysed. All patients had received bilateral neck dissection. The results indicated that if one internal jugular vein was preserved, bilateral neck dissection was safe and no fatal complications occur. In this series, most patients were of T3 and T4. The 3 and 5 year survival rates were 62% and 52% respectively. Cervical recurrence was the main reason for the deaths. It is suggested that for patients with advanced supraglottic laryngeal carcinoma, bilateral neck dissections are often needed, functional neck dissection, with preservation of at least one internal jugular vein is the best choice.

Adult↗
PubMed1997

[Expression of Epstein-Barr virus latent membrane protein (EBV-LMP) in human laryngeal carcinoma].

In order to investigate the expression of Epstein-Barr virus in human laryngeal carcinoma, immunohistochemical study for Epstein-Barr virus latent membrane protein (EBV LMP) was performed on 90 laryngeal specimens taken from laryngeal carcinoma patients. The results showed that LMP was localized on the cell membrane and in cytoplasm. LMP was detected in 41 of 90 (45.5%) laryngeal squamous cell carcinoma, among them the positive rates of poorly differentiated, middle differentiated and well differentiated squamous carcinoma were 44% (12/27), 52% (25/47) and 26.6% (4/15) respectively. This study indicated that EB virus was not only presented in poorly differentiated carcinoma, it was also presented in well differentiated carcinoma. The development of laryngeal squamous carcinoma is related to the infection of EB virus.

Adult↗
PubMed1997

[Microwave extraction technique].

A new microwave aided extraction (MAE) technique is introduced in this paper. It gives the extraction method as well as reagents, equipment and conditions used in the technique. In temperature controlled pressurized vessels, polar solvent (eg. acetone) and the combinations of polar and non-polar solvents can be heated to approximately 100 degrees C above their normal boiling points. It is told that the higher the extraction temperature the more the recovery is. The ratio of polar to non-polar solvents affects not only the microwave heating rate but also the extraction recovery. The highest recovery ratios are gotten at the solvent ratio of three parts of acetone to two parts of hexane. We can see from the pesticides chromatogram with MAE, that very little break-down of endrin or DDT are detected and they are well below the EPA specified tolerance limits. We can find from the comparison of MAE with sonication and Soxhlet extraction techniques that microwave extraction technique has not only higher average recoveries (%) but also good precision (RSD, %). The data and comparison results illustrate that the microwave extraction is a rapid method (about 15 minutes) with less solvent consumption (about 30-50 mL), good recovery, and easy to be controlled automatically in comparison with the Soxhlet extraction, sonication and other extraction methods.

Chemical Fractionation↗
PubMed1997

[Studies on the packings of high performance strong cation exchange chromatography for the separation of proteins].

In this paper, the studies on the synthesis, chromatographic characteristics and application of new packings of high performance strong cation exchange chromatography with sulfonic group for the separation of proteins have been reported. The silica with the end hydroxyl group reacted with chlorosulfonic acid and thus packings for high performance strong cation exchange chromatography were obtained. The recovery of bioactivity for lysozyme of these high resolution packings is over 76%. The packings can be used for the separation of proteins and biotechnological products.

Animals↗
PubMed1997

[Spectrophotometric studies on and applications of the reaction of copper with 2-hydroxy-3-carboxy-5-sulfobenzenediazoaminoazobenzene].

A highly sensitive color reaction of copper(II) with 2-hydroxy-3-carboxy-5-sulfobenzenediazoaminoazobenzene (HCSDAA) in the presence of Triton N-101 was studied in detail. In borax buffer medium at pH 10.4-11.5, the red complex formed has a maximum absorption at 530 nm and its apparent molar absorptivity is 1.31 x 10(5)L x mol(-1) x cm(-1) and sandell sensitivity is 4.85 x 10(-4) microg x cm(-2). The molar ratio of copper(II) to HCSDAA in the complex is found to be 1:2. Beer's law is obeyed in the concentraction range of 0-0.24 microg/mL for copper. The proposed method has been applied to the spectrophotometric determination of microamounts of copper in ore and peanut with the relative error and the relative standard deviation (n = 6) of less than 3.7% and 1.6%, respectively.

English Abstract↗
PubMed1997

Orphenadrine and methimazole inhibit multiple cytochrome P450 enzymes in human liver microsomes.

The specificities of orphenadrine and methimazole on eight human liver P450 enzyme activities were evaluated by studying the extent of inhibition at different concentrations in two protocols: competitive inhibition and preincubation. In the competitive inhibition protocol, orphenadrine decreased CYP2B6 marker activity up to 45-57% in human liver microsomes and up to 80-97% in cell microsomes containing cDNA-expressed CYP2B6. Orphenadrine strongly decreased CYP2D6 marker activity by 80-90%. Orphenadrine also partially decreased the CYP1A2, CYP2A6, CYP3A4, and CYP2C19 marker activities. In the preincubation protocol, orphenadrine decreased the CYP2B6 activity in cDNA-expressed cell microsomes to completion. In human liver microsomes, orphenadrine strongly decreased the marker activities of CYP2B6, CYP2D6, as well as CYP2C9; and partially decreased the marker activities of CYP1A2, CYP2A6, CYP3A4, and CYP2C19. In the competitive inhibition protocol, methimazole had no effect on the marker activities of CYP2E1 and CYP2A6; slightly decreased CYP2D6 marker activity; partially decreased the marker activities of CYP2C19, CYP2C9, and CYP2B6; and dramatically decreased CYP3A4 marker activity. Methimazole decreased CYP1A2 marker activity at lower concentrations, but not at the highest concentration studied (1 mM). In the preincubation protocol, methimazole was shown to be a potent and nonspecific inhibitor of all the enzyme activities. Marker activities of CYP2C9, CYP2C19, and CYP3A4 were completely inhibited at relatively low concentrations. This study indicates orphenadrine cannot be used as a selective inhibitor of CYP2B6 in human liver microsomes and that methimazole is not a selective inhibitor of the flavin-containing monooxygenase in human liver microsomes.

Antiparkinson Agents↗
PubMed1997

Free fatty acid turnover measured using ultralow doses of [U-13C]palmitate.

Low intravenous infusion rates of [U-13C]palmitate were used to measure systemic palmitate flux at rest (0.5 nmol . kg-1 . min-1) and during exercise (2 nmol . kg-1 . min-1) in healthy adults. The 13C enrichment of plasma palmitate was determined by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Palmitate flux was also measured using palmitate radiotracers, which were infused simultaneously to serve as a reference method. Flux values obtained using the two different methods were virtually identical. Overnight postabsorptive palmitate flux was measured on four occasions in three individuals; the flux values were highly reproducible with a coefficient of variation of 11% and 12% for intra-day measurement, and 13% and 8% for inter-day measurement, for [1-(14)C]palmitate and [U-(13)C]palmitate, respectively. During exercise, palmitate turnover measured with [U-(13)C]palmitate and [3H]palmitate were well correlated (r = 0.91). Compared to conventional stable isotope approaches, (e.g., [1-(13)C]palmitate analyzed by GC/MS), [U-(13)C]palmitate reduces the tracer dose by two orders of magnitude when the samples are analyzed with GC/C/IRMS. Uniformly labeled [13C]palmitate is suitable for the measurement of free fatty acid flux in humans.

Adult↗
PubMed1997

Studies on efficacy of praziquantel and mebendazole-medicated salt in treatment of Echinochasmus fujianensis infection.

The therapeutic effect of praziquantel and mebendazole-medicated salt has been studied in 109 cases with Echinochasmus fujianensis infection. These cases were randomly divided into four groups: 2 groups with a single dose of praziquantel 5 mg/kg or 2.5 mg/kg; and other 2 groups with mebendazole 800mg or 400 mg in 10d table salt. Four weeks after treatment, the egg negative conversion rates were 100%, 92.3%, 85.2% and 71.4% respectively, the egg reduction rates were 84.8-100%, and side-effects were mild. The symptoms caused by infection such as abdominal pain, diarrhea, distension and anorexia were obviously relieved. These data indicated that praziquantel is the drug of choice in the treatment of Echinochasmus fujianensis. The dosage is only 2.5 mg/kg, and its egg negative conversion rate and reduction rate reach 92.3% and 95.4%, respectively. For convenience, the dosage can be made according to their age. Children under 12 take half a tablet (100 mg), and one tablet (200 mg) for those over 12. This dosage is approximately equal to 2.5-5.0 mg/kg. Although the efficacy of mebendazole is lower than praziquantel, its egg negative conversion rate also reaches 71.4-85%. Mebendazole-medicated salt can be used for treating Echinochasmus fujianensis infection as the presence of co-infection with nematodes.

Adolescent↗
PubMed1997

An observation of the anastomoses of intrahepatic veins in normal human adults.

OBJECTIVE: To determine whether the hepatovenous intrahepatic anastomoses exist in normal humans. METHODS: A total of 13 livers were isolated during the early autopsies of normal men who died in accidents. Perfusion venography of the branches of hepatic veins using meglucamine diatrizoate was performed in 6 cases. This method of investigation has not been reported in the literature. In one case, a portal venography was done. In the remaining 6 cases, liver substance stainings were done by injecting ink through the middle hepatic vein, and the tissue sections of these livers were observed under light microscope. RESULTS: There were intrahepatic anastomoses between the hepatic veins within the liver. These anastomoses belonged to the 4th or 5th branch of hepatic vein near the capsule. There were also anastomoses between the middle hepatic vein and the hepatic short veins. Shunts existed between the portal veins and hepatic veins. CONCLUSIONS: The detection of anastomoses of intrahepatic veins in normal individuals provide anatomical rationale for the performance of irregular hepatectomy, as well as rationale for the ligation of one or two hepatic veins should such veins be traumatized or invaded by liver cancer.

Adult↗