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Biomedical subjects

Z H Liu

Publications and source records attributed to Z H Liu.

At least 55 records · Page 3Linked to original sources
PubMed1996

Localization of glutamic acid decarboxylase in the kidneys of nonobese diabetic mice.

Antibodies to glutamic acid decarboxylase (GAD), a pancreatic islet beta-cell antigen, are present in > 80% of newly diagnosed insulin-dependent diabetes mellitus (IDDM), and are found in nonobese diabetic (NOD) mice, a murine model of spontaneous IDDM. To determine whether GAD is a target antigen in the kidney damage of NOD mice, we studied GAD mRNAs (GAD65 and GAD67) by RT-PCR in mesangial cells, isolated glomeruli, and kidney cortex and medulla in NOD and SJL/C57BL mice. GAD mRNAs were detected in the cortex of both diabetic and nondiabetic NOD and SJL/C57BL mice and GAD antigen was present in proximal and distal tubules by immunofluorescence microscopy. Neither GAD antigen nor mRNA were present in mesangial cells or glomeruli of diabetic or nondiabetic mice. Thus, the expression of GAD in renal tubules raises the possibility that GAD antigens may play a role in diabetic tubulointerstitial disease, whereas the absence of these antigens in glomeruli suggests that GAD-triggered autoimmunity is not directly involved in the glomerular lesions.

Animals↗
PubMed1996

Immunoradiometric assay for follistatin: serum immunoreactive follistatin levels in normal adults and pregnant women.

A sensitive and specific immunoradiometric assay for follistatin was developed using antifollistatin mouse monoclonal and rabbit polyclonal antibodies. The sensitivity of the assay was 0.5 micrograms/L, and cross-reactivities with recombinant human activin A and bovine inhibin were less than 0.1%. The intra- and interassay coefficients of variation were less than 10%, and the recovery rate was about 90% in human serum. The addition of activin A to the same sample resulted in a minimal influence on follistatin recovery, indicating that this assay system can measure the total level of activin-bound and unbound follistatin. Gel filtration analysis of human serum showed that the majority of immunoreactivity was eluted in a larger molecular size position than that of free follistatin, suggesting that the large part of follistatin is bound to other proteins, presumably activins, in serum. Using this assay, immunoreactive follistatin levels in various biological fluids and human sera were examined. The dose-response curves of porcine follicular and amniotic fluids were parallel to the standard curve, and porcine follicular fluid contained extremely high follistatin immunoreactivity (5.6 mg/L). The serum follistatin level in normal human volunteers was 13.3 +/- 4.7 micrograms/L (mean +/- SD; n = 60), with a tendency to increase gradually with age. On the other hand, the serum follistatin level was remarkably elevated in pregnant women (62.7 +/- 35.3 micrograms/L; n = 57), with a positive correlation with weeks of pregnancy. These data indicated that circulating immunoreactive follistatin is detectable in human serum, and the levels vary with physiological conditions such as aging and pregnancy.

Activins↗
PubMed1996

Effects of LHRH, FSH and activin A on follistatin secretion from cultured rat anterior pituitary cells.

We demonstrated the release of follistatin, an activin-binding protein, from cultured rat anterior pituitary cells by measuring immunoreactive (ir-) follistatin in a specific immunoradiometric assay. Ir-follistatin release gradually increased in cultures over 1-18 days and reached its maximal level at 12-15 days of incubation. The basal ir-follistatin levels in the culture media increased about 3- (P < 0.01) and 5-fold (P < 0.001) in 2 and 10% fetal calf serum for 6 days, respectively. LHRH and activin A caused an approximately 2.0- (P < 0.05) and 1.8-fold (P < 0.05) rise in ir-follistatin release, respectively, in contrast to the lack of significant FSH effects. The culture medium condensed on sulfate-cellulofine gel was resolved by polyacrylamide gel electrophoresis and blotted with anti-follistatin polyclonal antibody, resulting in at least three protein bands ranging from 35 to 50 kDa under non-reducing conditions. These results indicated that follistatin is produced in anterior pituitary cells and that its secretion is regulated at least in part by LHRH and activin, implying an autocrine/paracrine role of activin and follistatin in the pituitary.

Activins↗
PubMed1996

Regulation of immunoreactive activin A secretion from cultured rat anterior pituitary cells.

Immunoreactive activin A (ir-activin A) release from cultured rat anterior pituitary cells was examined by measuring ir-activin A in culture medium by a specific radioimmunoassay. Ir-activin A release into the medium increased over 1-18 days, and reached a maximal level at 12-15 days. The basal levels of ir-activin A in the culture media were 0.70 +/- 0.10 (mean +/- SD), 1.30 +/- 0.36 and 1.83 +/- 0.44 ng/10(6) cells, when cultured for 6 days with 0, 2 and 10% fetal calf serum, respectively. LHRH induced an approximate 1.4-fold increase in ir-activin A release in contrast to a 40-60% inhibition with FSH, but LH did not affect the activin A release. In the presence of 12-o-tetradecanoylphorbol acetate (TPA), iractivin A release was enhanced, but no significant effect was induced by forskolin. Activin A was distinctly immunostained in cultured rat anterior pituitary cells. These results suggested that activin A release from the pituitary is modified by FSH and LHRH, and that the activation of protein kinase C may be involved in the action of LHRH.

Activins↗
PubMed1996

Effect of emodin on c-myc proto-oncongen expression in cultured rat mesangial cells.

AIM: To explore the possible molecular mechanism of emodin on the inhibition of glomerular mesangial cells (MC). METHODS: In rat MC culture, c-myc mRNA level was detected by dot-blotting as expressed by the dilutions of the total RNA on the visible dots. RESULTS: Low level c-myc mRNA was found in serum-free cultured quiescent MC. Addition of lipopolysaccharide (LPS 10 mg.L-1) induced a higher level expression of c-myc mRNA within 30 min, maximal expression at 2.5 h and persisted for 6 h. This over-expressing of c-myc mRNA was markedly suppressed by emodin (25 mg.L-1), the inhibition of emodin on c-myc mRNA expression was still seen at 6 h, and the greatest suppressive effect was at 2.5 h. CONCLUSION: Emodin participating in its down-regulatory effect of c-myc mRNA over-expression contributes to its inhibitory action on MC.

Animals↗
PubMed1996

Molecular analysis of glomerular diseases in renal biopsies: initial results of a collaborative international study. The International Study Group for Molecular Study of Kidney Biopsies.

An accurate assessment of which patient with glomerular disease will progress to end-stage renal failure would be an important addition to establishing prognosis and evaluating therapeutic strategies. We previously found the development of glomerular scarring in animal models was preceded by an increase in glomerular type IV collagen mRNAs and that the level of scarring predicted the rate of progression. The purpose of this study was to determine whether these findings apply to human glomerular diseases using microdissected glomeruli and assessment of mRNA by competitive PCR. After showing that the levels of type IV collagen mRNAs were elevated in sclerotic glomeruli isolated from nephrectomies, we undertook this preliminary cross-sectional study of type IV collagen subchain mRNAs in renal biopsies in two of the leading causes of glomerulosclerosis, diabetic nephropathy, and membranous glomerulopathy. We found that glomerular type IV collagen mRNA levels were altered in disease-specific ways. The relative levels of the individual alpha-chains of type IV collagen depended on the anatomic site of the glomerular lesions. The alpha 2 type IV/alpha 3 type IV collagen mRNA ratio was high in diabetes mellitus, but not in membranous glomerulopathy. These data, coupled with those obtained from experimental animals, suggest that a dysregulation of basement collagen synthesis underlies progressive glomerular scarring. If these conclusions are verified in prospective studies it will be feasible to assess the risk of developing progressive glomerulosclerosis in the individual patient and to quantitatively assess therapeutic responses in a timely manner.

Aged↗
PubMed1996

Tolerance of oocyte plasma membrane to electric current changes after fertilisation.

The tolerance of the oocyte plasma membrane (oolemma) to electrical pulses (TEP) was investigated for oocytes, zygotes, and embryos at the early and late 2-cell stage. The oocyte survival rate after two electrical pulses (1.4 kV/cm for 640 microns each) was used as an indicator of the TEP of the oolemma. Survival rate of mid-pronuclear zygotes (94.3% +/- 2.3%) was significantly (p < 0.05) higher than that of recently ovulated (2.1% +/- 1.9%) and in vivo aged (25.1% +/- 2.6%) oocytes; survival rate of in vivo aged oocytes was also significantly higher than that of recently ovulated oocytes. Soon after fertilisation, the survival rate of the oocytes markedly increased, up to 94% at the mid-pronuclear stage. Survival rate dropped thereafter. These results suggest that the characteristics of the oocyte plasma membrane (oolemma) change after fertilisation.

Animals↗
PubMed1996

[Experimental study on effect of Cordyceps sinensis in ameliorating aminoglycoside induced nephrotoxicity].

In order to evaluate the effect of Cordyceps sinensis (CS) on aminoglycoside (AG) induced nephrotoxicity, gentamycin was imposed on the young and old rats with CS administration. The renal tubular injury was ameliorated as evidenced by less prominent increment of BUN, SCr, sodium excretion, urinary NAGase and less severity of histopathological changes as compared with control. In addition, the use of CS could promote an earlier recovery of renal oxygen consumption insulin clearance, and sodium absorption in isolated perfused kidney from CS treated intoxicated rat than that from control. Possible mechanisms of CS on drug-induced nephrotoxicity include: (1) Accelerating the regeneration of tubular cells; (2) Protecting the sodium pump activity of tubular cells; (3) Attenuating the tubular cell lysosome hyperfunction stimulated by phagocytosis of AG as well as decreasing the tubular cell lipoperoxidation in response to toxic injury; (4) Reducing the tissue Ca++ content.

Acute Kidney Injury↗
PubMed1996

[Structure determination of korepimedoside A and korepimedoside B from Epimedium koreanum Nakai].

Two new flavonol glycosides were isolated from the aerial parts of Epimedium koreanum Nakai. On the basis of spectroscopic and chemical evidence, they were elucidated as anhydroicaritin 3-O-beta-D-(6-acetyl) glucopyranosyl (1-->3)-alpha-L-(4-acetyl) rhamnopyranoside and anhydroicaritin 3-O-beta-D-(2, 6-diacetyl) glucopyranosyl (1-->3)-alpha-L-(4-acetyl) rhamnopyranoside-7-O-beta-D-glucopyranoside, which were named korepimedoside A and korepimedoside B respectively.

Drugs, Chinese Herbal↗
PubMed1995

Calmodulin gene family in potato: developmental and touch-induced expression of the mRNA encoding a novel isoform.

Eight genomic clones of potato calmodulin (PCM1 to 8) were isolated and characterized. Sequence comparisons of different genes revealed that the deduced amino acid sequence of PCM1 had several unique substitutions, especially in the fourth Ca(2+)-binding area. The expression patterns of different genes were studied by northern analysis using the 3'-untranslated regions as probes. The expression of PCM1, 5, and 8 was highest in the stolon tip and it decreased during tuber development. The expression of PCM6 did not vary much in the tissues tested, except in the leaves, where the expression was lower; whereas, the expression of PCM4 was very low in all the tissues. The expression of PCM2 and PCM3 was not detected in any of the tissues tested. Among these genes, only PCM1 showed increased expression following touch stimulation. To study the regulation of PCM1, transgenic potato plants carrying the PCM1 promoter fused to the beta-glucuronidase (GUS) reporter gene were produced. GUS expression was found to be developmentally regulated and touch-responsive, indicating a positive correlation between the expression of PCM1 and GUS mRNAs. These results suggest that the 5'-flanking region of PCM1 controls developmental and touch-induced expression. X-Gluc staining patterns revealed that GUS localization is high in meristematic tissues such as the stem apex, stolon tip, and vascular regions.

Amino Acid Sequence↗
PubMed1995

Collagen and collagenase mRNAs in normal and sclerotic glomeruli: predictors of progression and response to therapy.

Progressive glomerulosclerosis is associated with decreasing kidney function, eventuating in end-stage renal failure. There are multiple components of the extracellular matrix, and the exact composition in various renal diseases is not known. Thus, we examined some of the major components of the extracellular matrix (ECM) in murine and human glomerular diseases. We studied matrix synthesis and degradation at the level of gene expression and ECM composition in the intact glomerulus. To determine whether the composition of sclerosis was similar among diseases, we examined a normal mouse strain and compared it with strains which spontaneously developed glomerulosclerosis. The baseline levels of matrix components varied between different mouse strains, and this level correlated with their propensity to develop glomerulosclerosis. In addition, when glomerulosclerosis was induced, the baseline ECM mRNA level predicted the subsequent outcome. We studied mice transgenic for bovine growth hormone, since they develop progressive glomerulosclerosis. Treatment with heparin substantially decreased the lesions without changes in type IV collagen mRNAs. However, there was an up-regulation of both the mRNA and enzyme activity for the 92 kD matrix metalloproteinase. In contrast, when these mice were treated with either angiotensin converting enzyme inhibitors or angiotensin II (Ang II) receptor antagonists, the glomerulosclerosis was accentuated histologically and the ECM synthetic and degradative mRNAs were elevated. These data suggest that the mRNA levels reflect response to therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Effects of Paeonia-glycyrrhiza decoction on changes induced by cisplatin in rats].

In order to study the effects of Paeonia-Glycyrrhiza decoction (PGD) on the changes induced by cisplatin in rats, platinum-wire bipolar electrodes were inserted into the serosal membrane of the small intestine and migrating myoelectric complex (MMC) was used as index. After intravenous injection of cisplatin at doses of 4 mg/kg, the duration of the MMC cycles was significantly shorter than that of normal MMC cycles (P < 0.05) while the duration of phase III was remarkably prolonged comparing with that of normal phase III (P < 0.01) with latent period of 53.2 +/- 20.4 minutes. Taking PGD orally, cisplatin no longer induced the changes of MMC. The results suggest that PGD has marked adjusting effects on the changes of MMC induced by cisplatin. This might be one of the causes of PGD in relieving diarrhea induced by cisplatin in rats.

Animals↗
PubMed1994

[Study of treatment on acquired infantile mental retardation with traditional Chinese and Western medicine].

80 cases with acquired infantile mental retardation caused by perinatal brain injury was treated with large doses of hyoscyamus, self made Retarded Recovery Pill and acupuncture. At the same time, 50 cases were taken as control group treated with Nao An Tai, Nao Fu Kang, etc. After 3 month treatment, the Intelligence Quotient (IQ) increased by 15 points in 29 cases of treatment group, while 3 cases in control group, chi 2 = 15.2, P < 0.01. After treatment for 6 month the IQ increased in 41 and 5 cases respectively, t = 5.53, P < 0.01. In 58.75% of the faculty of speech and motion greatly improved. It revealed that to treat the acquired infantile mental retardation, the combined therapy of traditional Chinese and Western medicine is effective.

Acupuncture Therapy↗
PubMed1994

Ethnic differences in disposition of antipyrine and acetaminophen between Tibetan and Han healthy volunteers.

The differences in disposition of antipyrine and acetaminophen between Tibetan and Han healthy volunteers were studied in a randomized crossover design. The half-life of antipyrine was found to be 18.8 +/- 4.89 h in 16 Han and 15.0 +/- 3.02 h in 17 Tibetan (P < 0.05) and the clearance was 1.35 +/- 0.37 L.h-1 in Han and 1.71 +/- 0.44 L.h-1 in Tibetan (P < 0.05). The half-life of acetaminophen was 3.1 +/- 0.86 h in Han and 3.2 +/- 1.12 h in Tibetan (P > 0.05). The experimental results indicate that the disposition of antipyrine between Tibetan and Han healthy volunteers significantly differed, the clearance of antipyrine in Tibetan increased by 20%, but the disposition of acetaminophen between the two ethnic groups showed no difference.

Acetaminophen↗