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Biomedical subjects

Z Xu

Publications and source records attributed to Z Xu.

At least 613 records · Page 34Linked to original sources
PubMed1989

[Effect of respiratory failure on water and sodium metabolism].

Water and sodium loading tests were undertaken in 27 cases of cor pulmonale with acute exacerbation. The results showed that ratio of 2 hour urine volume versus water load was 23- +/- 1.38% in respiratory failure (RF) group (17 cases), which was significantly lower than that of non-RF group (10 cases) 51.3 +/- 4.17%, (P less than 0.01) and control group (7 cases) 57.4 +/- 6.54%, (P less than 0.01); ratio of 4-hour urine sodium versus sodium load was 12.0 +/- 1.48% in RF group, which was also lower than that of non-RF group (29.6 +/- 1.93%, P less than 0.01) and control group (30.4 +/- 2.42%, P less than 0.01). It was suggested that excretions of water and sodium decreased in RF group. The incidences of hyponatremia and hyposmosemia were 47.1% and 64.7% respectively in RF group in 6 cases of RF with edema, the excretions of water and sodium increased after oxygen treatment. The mechanism and the clinical significance of hyponatremia and hyposmosemia and of impaired excretions of water and sodium in RF patients were discussed preliminarily. It is concluded that hypoxemia is one of the important causes of the disturbance in water and sodium metabolism.

Adult↗
PubMed1989

[Protective effects of berberine on spontaneous ventricular fibrillation in dogs after myocardial infarction].

The effects of berberine (Ber 5 mg/kg iv) on ventricular tachyarrhythmias and electrophysiologic consequences in both normal and ischemic myocardium were studied in the open-chest dogs subjected to programmed electrical stimulation (PES) and intimal surface anodal direct current stimulation of the circumflex coronary artery on 5-8 d after acute myocardial infarction. Its effects were compared with procainamide (PA). Both drugs distinctly lengthened the QTc interval and the effective refractory period (ERP) of normal and infarct myocardium in both ventricles and decreased the dispersion of ERP in infarct myocardium (IDR) as well as the dispersion of ERP in left ventricle (VDR). The PES-induced ventricular tachycardia (VT) or ventricular fibrillation (VF) was prevented in 4 out of 6 Ber treated and 5 out of 6 PA treated dogs. Ber prevented spontaneous VF in 4 dogs (n = 5). PA prevented spontaneous VF in 3 dogs (n = 5). Normal saline (NS) did not prevent PES-induced VT/VF and spontaneous VF. The results suggest that Ber may be effective in preventing the onset of reentrant ventricular tachyarrhythmias and sudden coronary death after myocardial ischemic damage.

Animals↗
PubMed1988

Ultrastructure and function of thrombocytes in a family with congenital bleeding tendency.

Freshly isolated blood from controls and from three members of a family with congenital bleeding tendency were examined with respect to ultrastructure of platelets. The fixation protocol, which included tannic acid, permitted the visualization of substructures in the marginal bundle. Whereas nearly all platelets from the controls had a discoid shape, those from one of the patients (mother of the other two cases) were mostly flat or else roundish with two or three marginal bundles in different orientations. One portion of the thrombocyte fraction of each person was briefly exposed to adenosine diphosphate in order to activate the platelets and thereby to induce shape changes. Most platelets from the controls reacted as expected by rounding up and by projecting some pseudopods. A certain percentage (between 10 and 20%) of the microtubules in these activated platelets had 14 or even 15 protofilaments. The platelets from patients (and in particular the mother) either reacted by an abnormal bulging of the cytoplasm or did not react visibly at all. The microtubules retained their 13-subunit composition or in the abnormally reacted ones often had an open C-shaped cross-sectional profile. The bleeding tendency in this family might be due to a defect in the cytoskeleton of the platelet making it unable to react properly to stimuli.

Adenosine Diphosphate↗
PubMed1988

The substructure of marginal bundles in human blood platelets.

A fixation protocol was worked out which permitted the visualization of the substructure of microtubules in human blood platelets. This protocol included a brief prefixation with 0.1% glutaraldehyde in a "polymerization mix buffer" including GTP, followed by a fixation mixture containing glutaraldehyde and tannic acid, and postfixation in 0.1% osmium tetroxide. The 13 individual protofilaments of the microtubules were clearly visible and had a triangular cross-sectional area. Filaments could be seen running alongside the microtubules and connected to them by many links. We term these filaments the "intertubular filaments." Some microtubules were incomplete and had a C-shaped profile; by serial sectioning it was seen that such microtubules were close to the terminal ends of the microtubules. A low percentage of the platelets had two marginal bundles oriented perpendicularly to each other.

Blood Platelets↗
PubMed1988

Early changes in the substructure of the marginal bundle in human blood platelets responding to adenosine diphosphate.

Human blood platelets were exposed to 10 microM adenosine diphosphate in order to induce shape changes and their ultrastructure was examined in preparations fixed with a glutaraldehyde-tannic acid mixture. Within 5 sec after the addition of ADP the marginal bundle along the perimeter of the platelet had undergone profound changes. The intertubular filaments of the marginal bundle were lost and, probably as a consequence, the microtubules were dispersed. The microtubules also had fragmented and appeared as straight rods rather than smoothly curved coils. Profiles with 14 or 15 protofilaments rather than the common 13-unit pattern were seen in 16% of the cross-sectioned microtubules. The proportion of incomplete (C-shaped) microtubules or of microtubules with an electron-dense interior also had increased and were interpreted as sections near the terminal ends of a microtubule. We interpret the C-shaped and the "filled" microtubules as signs of a disassembled microtubule and the 14- and 15-protofilament profiles as probably representing new (ends of) microtubules reassembled with a defective control of the proper structure.

Adenosine Diphosphate↗
PubMed1985

Trends in mortality from malignant mesothelioma of the pleura, and production and use of asbestos in Australia.

Annual mortality from malignant mesothelioma of the pleura (MMP) in Australia (as represented by ICD8 codes 163.0 and 212.4, and ICD9 codes 163 and 212.4) increased in men aged 30 years and older from about 0.5/100 000 in 1968-1970 to 2.1/100 000 in 1983. Corresponding rates in women varied from 0.1/100 000 to 0.2/100 000 between 1968 and 1980, then rose to 0.3/100 000 in 1983. The rise in MMP mortality in men probably corresponds to the increasing use of asbestos, particularly amosite, in Australia during and after World War II. That production and importation of amosite and crocidolite in Australia reached a peak in 1958 may mean that peak mortality from MMP will not be reached until the 1990s (allowing a 35-year lag period). Substantial increases in importation and later production, of chrysotile in the 1950s, 1960s and 1970s may lead to increases in the incidence of other asbestos-related cancers, not reflected in trends in the incidence of MMP.

Adult↗
PubMed1985

Cutaneous malignant melanoma and fluorescent lighting.

A population-based case-control study of cutaneous malignant melanoma occurring during 1980-81 was conducted in Perth, Western Australia. Three hundred and thirty-seven cases and 349 matched controls were reinterviewed in 1983 with regard to their fluorescent light exposure. The incidence rate of all melanomas was not associated with rate of exposure or cumulative exposure to all fluorescent lights or just those without diffusers. Separate analyses by histogenetic type and, where possible, body site of melanoma showed, in most instances, no consistent association between incidence rate of melanoma and exposure to fluorescent lights without diffusers. Incidence of melanomas of unclassifiable histogenetic type, however, increased with increasing duration of exposure (P-value for trend .02). This association was weaker and the P-value higher (.11) when exposure was considered only in residential rooms and offices, where light fittings are closest to the subject. Adjustment for the effects of total and intermittent sun exposure on melanoma rates did not alter the above trends appreciably.

Adolescent↗
PubMed1984

Schistosoma japonicum and colorectal cancer: an epidemiological study in the People's Republic of China.

Prevalence of infestation with Schistosoma japonicum was highly correlated with mortality from colorectal cancer in 89 communes in four counties of Jiangsu province, China (rank correlation coefficient = 0.68) in 1973-75, and with incidence of colorectal cancer in 24 communes of Haining county, Zhejiang province in 1977-79. No similar correlations were seen with lung cancer. The presence or absence of a past history of schistosomiasis was ascertained from 154 patients with cancer of the rectum, 98 patients with cancer of the colon and two sets of individually matched control patients. One set consisted of patients with non-gastrointestinal cancer and the other of near neighbours of the colorectal cancer patients. In patients with a history of schistosomiasis, relative risk of rectal cancer was 8.3 (95% confidence interval 3.1 to 22.6) when other cancer patients were used as controls and 4.5 (95% confidence interval 1.7 to 12.1) with neighbourhood controls. Relative risk of colon cancer was not significantly increased (1.20 with 95% confidence interval 0.48 to 3.18 in a matched triplet analysis) in association with schistosomiasis.

Adult↗
PubMed1984

The in situ activation of cytotoxic properties in murine Kupffer cells by the systemic administration of whole Mycobacterium bovis organisms or muramyl tripeptide.

We determined whether the systemic administration of viable Mycobacterium bovis organisms (BCG) or a lipophilic derivative of muramyl tripeptide (MTP-PE) would lead to the activation of antitumor properties in murine Kupffer cells (KC). KC-mediated tumor cytolysis was determined by the release of radiolabeled nuclear breakdown products of target cells. KC harvested from either C57BL/6 or C3H/HEN mice treated with saline exhibited no cytotoxicity against syngeneic B16 melanoma or UV-2237 fibrosarcoma cells. In contrast, KC harvested from BCG or MTP-PE-injected mice were highly cytotoxic against the tumor targets, as measured by an in vitro radiorelease assay. The demonstration that the administration of macrophage activators can generate in situ tumoricidal activity in KC suggests that these cells can be important in the control of hepatic micrometastases.

Acetylmuramyl-Alanyl-Isoglutamine↗