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Biomedical subjects

Z J Zhang

Publications and source records attributed to Z J Zhang.

At least 19 recordsLinked to original sources
PubMed1992

Down-regulation of the immune response to histocompatibility antigens and prevention of sensitization by skin allografts by orally administered alloantigen.

The effects of oral administration of major histocompatibility antigens on the alloimmune response have not been investigated. Lymphocytes from inbred LEW (RT1u) rats that were pre-fed allogeneic WF (RT1l) splenocytes exhibited significant antigen specific reduction of the mixed lymphocyte response in vitro and delayed-type hypersensitivity response in vivo, when compared with unfed controls. In an accelerated allograft rejection model, LEW rats were presensitized with BN (RT1n) skin allografts 7 days before challenging them with (LEW x BN)F1 or BN vascularized cardiac allografts. While sensitized control animals hyperacutely reject their cardiac allografts within 2 days, animals prefed with BN splenocytes maintained cardiac allograft survival to 7 days, a time similar to that observed in unsensitized control recipients. This phenomenon was antigen-specific, as third-party WF grafts were rejected within 2 days. Immunohistologic examination of cardiac allografts harvested on day 2 from the fed animals had markedly reduced deposition of IgG, IgM, C3, and fibrin. In addition, there were significantly fewer cellular infiltrates of total white blood cells, neutrophils, macrophages, T cells, IL-2 receptor-positive T cells, and mononuclear cells with positive staining for the activation cytokines IL-2 and IFN-g. On day 6 posttransplant, the grafts from fed animals showed immunohistologic changes typical of acute cellular rejection usually seen in unsensitized rejecting controls. Feeding allogeneic splenocytes prevents sensitization by skin grafts and transforms accelerated rejection of vascularized cardiac allografts to an acute form typical of unsensitized recipients. Oral administration of alloantigen provides a novel approach to down-regulate the specific systemic alloimmune response against histocompatibility antigens.

Administration, Oral↗
PubMed1992

[Quantitative analysis of compound injection of aminopyrine by dual-wavelength linear regression spectrophotometry].

A dual-wavelength linear regression spectrophotometry has been introduced and evaluated. Depending on a group of standard mixture solutions the optimal wavelengths and calibration curve can be determined simultaneously by linear regression method. The deviation of absorption resulting from molecular interaction can be calibrated by this method and the results are more accurate. The validity of this method has been confirmed through its use in the analysis of compound injection of antipyrine with satisfactory recoveries. Results obtained by Kalman filtering (KF), partial least squares (PLS) and target factor analysis (TFA) are also given.

Aminopyrine↗
PubMed1992

[Effects of castration and testosterone-replacement on hypothalamic and plasma luteinizing hormone-releasing hormone levels in the aged male rat].

Hypothalamic and plasma luteinizing hormone-releasing hormone (LHRH) levels following orchidectomy (ORDX) and testosterone (T)-replacement were compared between young (2-3 months old) and aged (24-26 months old) male rats by radioimmunoassay. Plasma T level and hypothalamic LHRH content are markedly decreased in the aged rat as compared to those of the young rat, whereas plasma LHRH levels are similar in the two groups. Following ORDX and ORDX plus T-replacement, plasma T levels in both groups are about the same, whereas the rates of variation of hypothalamic and plasma LHRH levels in the aged rat are significantly lower than those in the young rat. These results suggest that the negative feedback mechanism of the hypothalamic LHRHergic system is impaired in the aged rat, which may be one of the important reasons causing age-dependent deterioration of the functional control of hypothalamic-pituitary-testicular axis.

Aging↗
PubMed1991

Suppression of diabetes in nonobese diabetic mice by oral administration of porcine insulin.

Nonobese diabetic (NOD) mice spontaneously develop an autoimmune form of diabetes associated with insulitis. A number of immunomodulatory therapies have been investigated as a treatment for the disease process. Oral administration of the autoantigens myelin basic protein and collagen type II suppresses experimental models of encephalomyelitis and arthritis. We have now found that oral administration of insulin delays the onset and reduces the incidence of diabetes in NOD mice over a 1-year period in animals administered 1 mg of porcine insulin orally twice a week for 5 weeks and then weekly until 1 year of age. As expected, orally administered insulin had no metabolic effect on blood glucose levels. The severity of lymphocytic infiltration of pancreatic islets was also reduced by oral administration of insulin. Furthermore, splenic T cells from animals orally treated with insulin adoptively transfer protection against diabetes, demonstrating that oral insulin administration generates active cellular mechanisms that suppress disease. These results show that oral insulin affects diabetes and the pancreatic cellular inflammatory process in the NOD mouse and raise the possibility that oral administration of insulin or other pancreatic autoantigens may provide a new approach for the treatment of autoimmune diabetes.

Administration, Oral↗
PubMed1991

Metabolism of n-3 polyunsaturated fatty acids by the isolated perfused rat liver.

The hepatic metabolism of oleic acid and n-3 fatty acids (eicosapentaenoic acid, EPA and docosahexaenoic acid, DHA), and secretion of very low density lipoprotein (VLDL) were studied in isolated perfused rat livers from normal chow fed male rats. The basal perfusion medium contained 30% bovine erythrocytes, 6% bovine serum albumin (BSA), and 100 mg/dL glucose, in Krebs-Henseleit bicarbonate buffer (pH 7.4), which was recycled through the liver for 2 hr. Individual fatty acids (EPA, DHA or oleic acid), as complexes with 6% BSA, or albumin alone, were infused at a rate of 70 mumol/hr. When any of these fatty acids was infused at this rate, the ambient concentration in the medium was maintained at 0.3-0.4 mumol/mL, indicative of similar hepatic rates of uptake for each fatty acid (i.e., approximately 6 mumol/g liver/hr). When fatty acid was not infused, the ambient free fatty acid level was 0.16 mumol/mL. The concentrations of infused free fatty acids increased appropriately in the perfusion medium; however, with infusion of EPA, DHA, or oleate, the concentrations of perfusate palmitate and linoleate were the same as when fatty acid was not infused. Additionally, the perfusate concentration of oleate in the free fatty acid fraction was not affected by infusion of EPA and DHA. These data indicate a constant outflow of endogenous fatty acid unaffected by the presence of the exogenously supplied fatty acid. The net secretion rate of VLDL lipids and protein was stimulated by infusion of oleate, whereas when EPA was infused, secretion rates were lower and similar [except for VLDL cholesterol (C), which was greater] to those occurring when fatty acid was not provided.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[Low-dose aspirin preventing pregnancy induced hypertension].

A prospective randomized double-blind study was carried out in pregnant women with risk of pregnancy induced hypertension (PIH). Low dose Aspirin (50 mg/day) or placebo was given consecutively from the 28th weeks of gestation. The results have shown that 8% of the pregnant women in the aspirin treatment group had developed PIH, which was substantially lower than that in the control group (24%) (P less than 0.05). The ratio of TXB2/6-keto-PGF1 alpha increased significantly in the control group while it remained unchanged in treatment group. Increasing plasma fibronectin (Fn) and decreasing AT-III level were seen in the control group but no changes of these parameters in the treatment group. It was presumed that low dose aspirin may have prophylactic effect on PIH. The mechanism of aspirin may be the inhibition of TXA2 and Fn synthesis and decreased consumption of AT-III.

6-Ketoprostaglandin F1 alpha↗
PubMed1991

Case-control study on pathogenesis of pneumonia in children aged 0-2 years.

In order to know the incidence of risk factors predisposing children to pneumonia, case control study was carried out in six MCH Model Counties in 1986. Single factor analysis showed 29 factors were responsible for the increasing incidence of pneumonia. 13 of 29 factors were major pneumonia risk factors by the standard of means greater than 15 and OR greater than 3. They were malnutrition, anemia, riskets, pneumonia history, repeated colds, chronic diarrhoea, congenital malformation, asphyxia neonatorum, amniotic fluid aspiration, artificial feeding, too much clothing, family member with acute respiratory illness (ARI) and contact with ARI patients. Among them 7 factors were related to individual health condition. Therefore, it is important to improve general health of children so as to reduce the incidence of pneumonia.

Case-Control Studies↗
PubMed1991

Comparative efficacy of levo-praziquantel and praziquantel in treatment of schistosomiasis japonica at a single dose.

The result of a randomized double blind comparison of therapeutic efficacy of single doses of levo-praziquantel (L-PZQ) and praziquantel (PZQ) in the treatment of 139 matched pairs of proved cases of schistosomiasis japonica was reported, 268 were chronic early cases and 10 were late cases. The dosage of L-PQZ was 20 mg/kg, and that of PZQ was 40 mg/kg. Four and 6 months after treatment the stool-ova negative conversion rates were 94.8% and 96.3% for the L-PZQ group, and 97.1% and 94.0% for the PZQ group respectively (P greater than 0.05).

Adolescent↗
PubMed1990

The primary structure of rat liver glycogen synthase deduced by cDNA cloning. Absence of phosphorylation sites 1a and 1b.

The cDNA for rat liver glycogen synthase was isolated by screening a rat liver cDNA library constructed in lambda gt11. The cDNA was 2.4 kilobases in length and encoded a protein of 703 amino acid residues with a molecular mass of 80.5 kDa. Comparison of the rat liver and the human muscle sequences show that the amino- and carboxyl-terminal regions are quite divergent as compared to the internal sequences which show an 80% identity. The rat liver carboxyl-terminal region is truncated by 33 residues and has only 46% identity with the muscle sequence but retains the common feature of a low content of hydrophobic amino acids (13%). Phosphorylation sites 1a and 1b, which are the primary targets for phosphorylation by cAMP-dependent protein kinase, are absent in the liver sequence. The presence of these divergent, structurally anomalous carboxyl-terminal regions in liver and muscle glycogen synthase suggests the absence of the requirement that they possess a tertiary structure that is integral to that of the protein core. A model is proposed in which this region interacts with a catalytic core to maintain the I state, and in which phosphorylation serves to uncouple this interaction.

Amino Acid Sequence↗
PubMed1990

Maximum acceptable repetitive lifting workload by Chinese subjects.

This study used psychophysical methods to determine the acceptable mean maximum lifting workload for eight Chinese young male subjects, and examined the effects of lifting technique (including freestyle, stoop and squat), lifting frequency (including 2, 3, 4, 5 and 6 lifts/min) and physical characteristics on the maximum acceptable workload. The results are described as follows: (1) The maximum acceptable weights selected by subjects varied from 11.34 to 18.33 kg with changes in lifting technique and frequency. These data were lower than those previously obtained; (2) The upper limit of physiological tolerance over an 8 h workday was also generally lower than previously suggested. However, this upper limit varied with changes in lifting technique and frequency, and in some circumstances it was the same as or even higher than previous limit; (3) Lifting efficiency was affected significantly by technique and frequency. The rank order of efficiency for three lifting techniques were freestyle, stoop and squat. Efficiency was greatest when lifting frequency was between 5 and 6 lifts/min; and (4) The correlations between the maximum acceptable workloads selected by subjects and anthropometric sizes were significant, but those between maximum acceptable workload and isometric strength were not.

Adult↗
PubMed1990

[Study of Doppler flow velocity wave forms of the fetal umbilical artery].

400 umbilical arterial wave forms were determined in 120 cases of normal pregnancy. The systolic/diastolic (S/D) ratio of umbilical doppler flow velocity wave declined gradually from 3.3 to 2.2 during the period of 28th to 40th week, It was shown that the utero resistance was reduced and the placental blood perfusion was good. 67 umbilical arterial wave forms were determined in 33 cases of pregnancy induced hypertension. There were 20 cases of IUGR or fetal distress with abnormal umbilical arterial S/D ratio. The incidence of IUGR was 27% (9/33). The results show that this is a good, non-invasive and practical method for predicting fetal outcome. In combination with NST and biophysical profile it can serve as an antepartum assessment of fetal well being and is of much valve to eugenics and perinatology.

Blood Flow Velocity↗
PubMed1990

[Cesarean section in pregnancy complicated by severe hepatitis and heart disease].

In this article, we reported the analysis of two severe diseases complicating pregnancy: 1,918 cases of heart disease in last 36 years and 22 cases of severe hepatitis in last 16 years. The conclusion was that on active therapy and close cooperation with cardiologist, pregnancy complicated with heart disease of grade III-IV cardiac function can be taken as an indication of Cesarean section. This operation performed at a proper time is good for the mother and also the baby. The traditional idea that Cesarean section could only be done for an obstetrical reason is not quite adequate. For primiparas with severe hepatitis, a supportive therapy with fresh blood transfusion, albumin and Cesarean section under local anesthesia might be the method of choice, its mortality rate being much lower than a vaginal delivery.

Cesarean Section↗
PubMed1990

[Surveillance and control of ARI among urban nurseries in Beijing].

A study on acute respiratory infectious was carried out in four kindergartens in Beijing from September, 1984 to August, 1987. The results showed that ARI incidence rate in the children aged 0-7 years was 348.3%. Most of the cases were upper respiratory infectious. The incidence rate of pneumonia was 2.7%. The relationship between ARI incidence rate and age group showed that incidence of URI of 0-2 age group was 1.5 times higher than that of 5-7 age group, while the incidence of LRI of that 0-2 age group was 6.3 times higher than the later age group. The peak season of ARI was from October to January each year. The virus infections showed its priority in ARI. Duplicate samples of sera of 240 cases were tested. In which 122 cases were proved positive. Some strains of virus were isolated as well. It was showed that the influenza virus and adenovirus were the common pathogens of ARI. The effect of killed BCG(orally) on preventing ARI was observed. The preliminary date indicated the potential effect for the prevention of ARI by this measure.

BCG Vaccine↗