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Biomedical subjects

W Zou

Publications and source records attributed to W Zou.

At least 37 records · Page 2Linked to original sources
PubMed2001

Targeted disruption of luteinizing hormone/human chorionic gonadotropin receptor gene.

LH/hCG receptors were disrupted by gene targeting in embryonic stem cells. The disruption resulted in infertility in both sexes. The gonads contained no receptor mRNA or receptor protein. Serum LH levels were greatly elevated, and FSH levels were moderately elevated in both sexes; estradiol and progesterone levels decreased but were not totally suppressed in females; testosterone levels were dramatically decreased and estradiol levels moderately elevated in males. The external and internal genitalia were grossly underdeveloped in both sexes. Abnormalities included ambiguous vaginal opening, abdominal testes, micropenis, dramatically decreased weights of the gonads and reproductive tract, arrested follicular growth beyond antral stage, disarray of seminiferous tubules, diminished number and hypotrophy of Leydig cells, and spermatogenic arrest beyond the round spermatid stage. LH/hCG receptor gene disruption had no effect on FSH receptor mRNA levels in ovaries and testes, progesterone receptor (PR) levels in ovaries and androgen receptor (AR) levels in testes. However, it caused a dramatic decrease in StAR and estrogen receptor-alpha (ERalpha) mRNA levels and an increase in ERbeta mRNA levels in both ovaries and testes. Estradiol and progesterone replacement therapy in females and testosterone replacement in males, to determine whether phenotype and biochemical changes were a consequence of decreased gonadal steroid levels or due to a loss of LH signaling, revealed complete restoration of some and partial restoration of others. Nevertheless, the animals remained infertile. It is anticipated that the LH receptor knockout animals will increase our current understanding of gonadal and nongonadal actions of LH and hCG.

Animals↗
PubMed2001

Characterisation of cytokine mRNA expression in tumour-infiltrating mononuclear cells and tumour cells freshly isolated from human colorectal carcinomas.

The in situ function of tumour-infiltrating leukocytes (TIL) in human colorectal adenocarcinoma (CRC) is unclear. Local cytokine expression probably regulates the anti-tumour immune response and tumour immune surveillance. We examined the distribution of mRNA for IFN-gamma, TNF-alpha, IL-10 and IL-4 in TIL, and tumour cells freshly isolated from 21 surgically removed primary CRC, using a semiquantitative RT-PCR. Lamina propria-infiltrating leukocytes (LPL) and epithelial cells from normal colon mucosa of 10 CRC patients served as negative controls. Median levels of IFN-gamma and TNF-alpha mRNA were higher in TIL than LPL (p = 0.0002 and 0.0001). IL-10 mRNA was generally observed in TIL and LPL, but no or very small amounts of IL-4 transcripts were detected in TIL and LPL. TNF-alpha and IL-10 mRNA were more abundant in colorectal tumour cells than in the normal epithelial cells (p = 0.0136 and 0.0036). The number of IFN-gamma transcripts in TIL correlated negatively (p = 0.039) and the number of TNF-alpha transcripts in tumour cells correlated positively with the Dukes' stages (p = 0.0147). Our results suggest that TIL are characterized by a type 1 (Th1/Tc1-like) pattern of cytokine expression and function as T cells (and macrophages) in the local, cell-mediated anti-tumour immune response in early stages of CRC. Changes in IFN-gamma and TNF-alpha mRNA in TIL and tumour cells could be related to tumour progress (e.g. by T cell anergy) or forming of metastases, respectively.

Adenocarcinoma↗
PubMed2001

[Malignant hypertension presenting with renal damage: a clinical and pathological analyses].

OBJECTIVE: To evaluate the clinical features and pathological characteristics of malignant hypertension (MHPT) with renal damage. METHODS: The blood pressure, eye ground, urinalysis, renal function and extrarenal presentations of malignant hypertension patients, who had been hospitalized in recent eleven years, were analyzed retrospectively. There were 27 patients, 21 males and 6 females, aged from 19 to 51 years. At the same time, the clinical and pathological features of primary MHPT were compared with those of renal parenchymal MHPT. RESULTS: Among these patients, primary hypertension was diagnosed in 10 cases (37%), glomerulonephritis in 10 cases (37%), renovascular hypertension in 1 case (3.7%), and undetermined etiology in 6 cases (22.3%). The common renal presentations were those of rapidly progressive glomerulonephritis (RPGN) and progressive renal failure. Compared with those who were diagnosed as renal parenchymal MHPT, primary MHPT patients had lower urinary protein excretion (P = 0.001) and most of them had family history of hypertension. Renal biopsy was done in 13 cases, revealing primary MHPT in 4 cases and glomerulonephritis in 9. Typical pathological findings for primary MHPT were fibroid necrosis, marked intimal hyperplasia ("onion skin" like change) and ischemic changes of glomeruli. Severe glomerulonephritis, hyalinosis and thickening of renal arterioles were the main changes in MHPT with renal parenchymal diseases. After intensive therapy, the renal functions of some primary MHPT patients improved markedly. CONCLUSION: Malignant hypertension presenting with renal damage was not very rare. It was usually misdiagnosed. The clinical presentations, pathological findings and prognosis of primary MHPT were different from those of renal parenchymal MHPT.

Adult↗
PubMed2001

[A clinical and pathological analysis of 41 patients with anti-glomerular basement membrane antibody related diseases].

OBJECTIVE: To investigate the clinical and pathological characteristics of anti-glomerular basement membrane (GBM) antibody associated diseases with different clinical patterns. METHODS: The clinical and pathological data of 41 patients with anti-GBM antibody associated diseases, screened in our institute in recent six years, were retrospectively analyzed. RESULTS: 22 of the 41 patients presented as Goodpasture syndrome, 2 of them having normal renal function. 32 of the 41 patients had anti-GBM antibody positive only (single positive). 31 of the 32 single positive patients were male with an average age of (26.8 +/- 9.7) years. The remaining 9 patients were both anti-GBM antibody and antineutrophil cytoplasmic antibody (ANCA) positive (double positive); 7 of the 9 were female with an average age of (44.5 +/- 19.6) years. There was significant difference in gender and age between the single and double positive groups (P < 0.05). 30 of the 32 patients with renal biopsy had crescentic glomerulonephritis and the remaining two with normal renal function had mild mesangial proliferative glomerulonephritis only. 24 of the 30 (80%) crescentic glomerulonephritis patients had all glomeruli affected by crescents with severe glomerular capillary loop and Bowman's capsule damage. With immunofluorescence examination, 16 of the 23 cases had typical IgG and C(3) linear deposition along glomerular capillary walls, but the remaining 7 had fine granular IgG and/or C(3) deposition. In a few cases, granular deposition was found even in mesangium. There was no correlation between the immunofluorescence patterns and the severity of glomerular damage (P > 0.05). All patients had anemia, hematuria and proteinuria, 7 of the 41 cases presented as nephrotic syndrome. After intensive immunosuppressive therapy, only four patients, including the two patients with normal renal functions, achieved remission, the remaining patients either were in renal replacement therapy or died. CONCLUSIONS: Anti-GBM antibody associated diseases are not rare in China. Single positive patients are mainly young male, while double positive patients are mainly middle-aged female. Most of the patients with anti-GBM antibody associated diseases have crescentic glomerulonephritis (rapidly progressive glomerulonephritis, RPGN) with a bad prognosis. However, not all the patients have typical linear deposition of IgG and C(3) along glomerular capillary walls. Only a few non-oliguric patients with normal renal function or mild renal damage may achieve remission.

Adolescent↗
PubMed2000

Cytochemical evaluation of localization and secretion of a heterologous enzyme displayed on yeast cell surface.

A starch-utilizing Saccharomyces cerevisiae strain was constructed by cell surface engineering. Distribution of the heterologous glucoamylase-alpha-agglutinin fusion protein on the yeast cell was analyzed by indirect fluorescence microscopy using an anti-glucoamylase antibody. Most of the intense fluorescence was first localized in the small bud, then observed on the entire cell wall of the daughter and mother cells. Fluorescence also accumulated at the neck region. These observations suggest that the display of the heterologous protein on the cell surface is carried with other cell wall components to the areas in which the cell wall is newly synthesized; the distribution is controlled by the cell cycle. Then, the heterologous protein-encoding gene was expressed in a sec1 mutant, in which secretory vesicles accumulate under restrictive temperature, and the produced protein was detected by immunoelectron microscopy. Most of the gold particles that reacted with the fusion protein were not localized in vesicles but in expanding endoplasmic reticulum. This phenomenon may be due to overproduction of the heterologous protein which was designed to be displayed on the cell wall. Artificial production of heterologous protein may have caused a relative shortage of glycosyl phosphatidylinositol anchors.

Agglutinins↗
PubMed2000

Macrophage-derived dendritic cells have strong Th1-polarizing potential mediated by beta-chemokines rather than IL-12.

Monocyte-derived dendritic cells (MDDCs) activate naive T lymphocytes to induce adaptive immunity, effecting Th1 polarization through IL-12. However, little is known about other potential DC Th1 polarizing mechanisms, or how T cell polarization may be affected by DCs differentiating in, or exposed to, a proinflammatory environment. Macrophages (MPhis) are DC precursors abundant in inflamed tissues, lymph nodes, and tumors. Thus we studied the T cell-activating and -polarizing properties of MPhi-derived DCs (PhiDCs). Monocytes were cultured in MPhi-CSF (M-CSF) to produce MPhis, which were then differentiated into DCs following culture with GM-CSF plus IL-4. PhiDCs activated a significant allogeneic MLR and were significantly better than MDDCs in activating T cells with superantigen. Most strikingly, PhiDCs elicited up to 9-fold more IFN-gamma from naive or Ag-specific T cells compared with MDDCs (with equivalent IL-4 secretion), despite producing up to 9-fold less IL-12. Neutralization of MDDC, but not PhiDC IL-12 significantly inhibited T cell IFN-gamma induction. PhiDCs produced up to 12-fold more beta-chemokines (macrophage-inflammatory protein-1alpha, -1beta, and RANTES) than MDDCs. Ab blockade of CCR5, but not CXC chemokine receptor 4, inhibited T cell IFN-gamma induction by PhiDCs significantly greater than by MDDCs. Thus DCs differentiating from MPhis induce T cell IFN-gamma through beta-chemokines with little or no requirement for IL-12. Myeloid DCs arising from distinct precursor cells may have differing properties, including different mechanisms of Th1 polarization. These data are the first reports of IFN-gamma induction through chemokines by DCs.

Antigens, CD↗
PubMed2000

Genetic influence on the structural variations of the abnormal prion protein.

Prion diseases are characterized by the presence of the abnormal prion protein PrP(Sc), which is believed to be generated by the conversion of the alpha-helical structure that predominates in the normal PrP isoform into a beta-sheet structure resistant to proteinase K (PK). In human prion diseases, two major types of PrP(Sc), type 1 and 2, can be distinguished based on the difference in electrophoretic migration of the PK-resistant core fragment. In this study, protein sequencing was used to identify the PK cleavage sites of PrP(Sc) in 36 cases of prion diseases. We demonstrated two primary cleavage sites at residue 82 and residue 97 for type 1 and type 2 PrP(Sc), respectively, and numerous secondary cleavages distributed along the region spanning residues 74-102. Accordingly, we identify three regions in PrP(Sc): one N-terminal (residues 23-73) that is invariably PK-sensitive, one C-terminal (residues 103-231) that is invariably PK-resistant, and a third variable region (residues 74-102) where the site of the PK cleavage, likely reflecting the extent of the beta-sheet structure, varies mostly as a function of the PrP genotype at codon 129.

Brain Chemistry↗
PubMed2000

Modifier effects on column efficiency in packed-column supercritical fluid chromatography

We investigate the effects on column efficiency of methanol, acetonitrile, ethanol, and 1-propanol used as modifiers in packed-column SFC. C-18, phenyl, and cyano columns were used with both nonpolar and polar solutes. For highly retained nonpolar solutes, addition of modifier significantly increased apparent column efficiency, especially for the C-18 column. For polar solutes, the presence of modifier dramatically improved retention and efficiency with an apparent efficiency dependence on modifier type and amount. Temperature and pressure effects on efficiency were also studied.

Journal Article↗
PubMed2000

Establishment of a simple system to analyse the molecular interaction in the agglutination of Saccharomyces cerevisiae.

Saccharomyces cerevisiae a-agglutinin, which is involved in mating and covalently anchoring to the cell wall, consists of two components, Aga1p and Aga2p, whose syntheses are individually regulated. To facilitate the analysis of the protein-protein interaction on agglutination between a- and alpha-agglutinins, the construction of a yeast strain (MATa) with the functional protein prepared by genetic fusion of Aga1p- and Aga2p-encoding genes and by the expression system using the UPR-ICL promoter derived from the n-alkane-assimilating yeast, Candida tropicalis, which is functional under the condition of lower glucose concentration was tried and the agglutination ability of the constructed strain was evaluated with a yeast strain (MATa) which expressed AGalpha1 encoding alpha-agglutinin under the control of the same promoter. The genes were integrated into the yeast chromosomes. Cell agglutination between both (MATa) strains was observed microscopically when these two strains were mix-cultured to a glucose-decreased concentration. The agglutination was further confirmed by the sedimentation test and by the quantification using a filter. These results proved that the constructed Aga1p-Aga2p fusion protein was enoughly functional for the interaction with the Agalpha1 protein, and that this phenomenon occurred dependent on glucose concentration, but independent of the peptide pheromones secreted by the cells of the opposite mating types. Using this system, the role of two disulphide linkages between Aga1p and Aga2p on the binding activity between Aga2p and Aga1p was first evaluated. Under the treatment by the SH-compound (dithiothreitol), in which Agalpha2p is easily released into the medium from the intact cell surface, the Aga1p and Aga2p fusion protein was a good tool to make clear the role of the disulphide linkages. As a result, the linkages had a significant effect on not only the assembly but also the binding activity. The novel and simple system described here may further facilitate the study of molecular interaction in agglutination.

Alkanes↗
PubMed2000

Screening of genes involved in isooctane tolerance in Saccharomyces cerevisiae by using mRNA differential display.

A Saccharomyces cerevisiae strain, KK-211, isolated by the long-term bioprocess of stereoselective reduction in isooctane, showed extremely high tolerance to the solvent, which is toxic to yeast cells, but, in comparison with its wild-type parent, DY-1, showed low tolerance to hydrophilic organic solvents, such as dimethyl sulfoxide and ethanol. In order to detect the isooctane tolerance-associated genes, mRNA differential display (DD) was employed using mRNAs isolated from strains DY-1 and KK-211 cultivated without isooctane, and from strain KK-211 cultivated with isooctane. Thirty genes were identified as being differentially expressed in these three types of cells and were classified into three groups according to their expression patterns. These patterns were further confirmed and quantified by Northern blot analysis. On the DD fingerprints, the expression of 14 genes, including MUQ1, PRY2, HAC1, AGT1, GAC1, and ICT1 (YLR099c) was induced, while the expression of the remaining 16 genes, including JEN1, PRY1, PRY3, and KRE1, was decreased, in strain KK-211 cultivated with isooctane. The genes represented by HAC1, PRY1, and ICT1 have been reported to be associated with cell stress, and AGT1 and GAC1 have been reported to be involved in the uptake of trehalose and the production of glycogen, respectively. MUQ1 and KRE1, encoding proteins associated with cell surface maintenance, were also detected. Based on these results, we concluded that alteration of expression levels of multiple genes, not of a single gene, might be the critical determinant for isooctane tolerance in strain KK-211.

Blotting, Northern↗
PubMed2000

Pretreatment expression of the perforin gene by circulating CD8(+) T lymphocytes predicts biochemical response to interferon-alpha in patients with chronic hepatitis C.

It would be of great value to be able to predict, before the initiation of treatment, which patients with hepatitis C virus-induced chronic hepatitis will be cured by interferon-alpha (IFN-alpha). Competitive RT-PCR was used to evaluate spontaneous expression of the perforin gene, a marker of cytotoxic cell activation, by circulating mononuclear cells in 17 patients undergoing IFN-alpha treatment. IFN-alpha increased perforin gene expression (p < 0.003), but this was not correlated with outcome. In contrast, pretreatment perforin gene expression levels were higher in the 8 patients with a sustained biochemical response after treatment than in the 9 non-responsive patients (p = 0.01). This factor predicted favorable clinical outcome with a sensitivity of 75% and a specificity of 89%. Thus, pretreatment immunological status has a major influence on the ability of IFN-alpha to cure chronic hepatitis C, and the evaluation of perforin gene expression may help to select patients that will benefit from IFN-alpha treatment.

Adult↗
PubMed2000

[Comparison of the expression and activity of phosphatidylethanolamine N-methyltransferase 2 between primary cultured hepatocytes and hepatoma cells in rats].

OBJECTIVE: To compare the expression and activity of phosphatidyl-ethanolamine N-methyltransferase 2 (PEMT(2)) between the primary cultured hepatocytes and CBRH7919 hepatoma cells in rats. METHODS: The expression and activity of PEMT(2) were demonstrated by immunochemistry, Western immunoblotting and [(3)H-CH(3)] SAM incorporation. Flow cytometry (FCM) was used to investigate the DNA content of the cells. RESULTS: PEMT(2) expression and activity were higher in the primary cultured hepatocytes than in hepatoma cells. Cell cycle analysis showed that the proportion of the hepatocytes was higher in G(1) phase and lower in S phase in the primary cultured hepatocytes than hepatoma cell lines. CONCLUSION: There is an intimate relationship between the expression of PEMT(2) and the proliferation of hepatocytes.

Animals↗
PubMed2000

PrP(Sc) typing by N-terminal sequencing and mass spectrometry.

The heterogeneity of the clinicopathological phenotype in human prion diseases is associated with the presence of the different forms of the abnormal prion protein, PrP(Sc). We have previously shown that PrP(Sc) in FFI and a subtype of familial CJD linked to the D178N mutation can be distinguished by their difference in gel mobility following proteinase K (PK) treatment. To further characterize the structural difference of PrP(Sc) in familial prion diseases, N-terminal sequencing and mass spectrometry were used to identify the protease cleavage sites in PrP(Sc) extracted from affected brains. We found that the main PK cleavage sites of PrP(Sc) are located at residue 97 in FFI, and residue 82 in both CJD178 and a GSS subtype linked to the P102L mutation. The differential accessibility to protease in the native PrP(Sc) suggests that PrP(Sc) exist as distinct conformers in different disease states.

Brain↗
PubMed2000

[Two-phase linear models of leaf emergence at different tillering positions in wheat and effects of different varieties and sowing dates].

Dynamics of leaf emergence shows the development progress and its relationship with growth in wheat. It was found that two-phase linear model equations (phase I faster than phase II) divided by glum differentiation stage could describe leaf emergence progress in relation to growing degree days (GDD) after sowing in wheat. This pattern was consistent in main stems and tillers of normal development with both winter-and-spring type varieties. The beginning of phase II shifted to an earlier development stage on main stems of winter type varieties of early planting (EP, September 30) and late planting (LP, March 2), and on T3 of both varieties of EP, MP (middle planting, on October 30) and LP due to their abnormal development. The thermal rate of leaf emergence on main stem was relatively high and steady during development for winter type variety of MP, and quickened with the postponing of sowing for spring type variety. The above results illustrated the difference of leaf emergence at different tillering positions, and the biological characteristics affected by different varieties and sowing dates.

Germination↗
PubMed2000

[The role of bFGF in renal tubular injury and the interstitial lesion].

OBJECTIVE: The role of bFGF in renal tubular injury, regeneration and interstitial lesion of rats was studied. METHODS: The renal tubular injury model of rat was induced by intraperitoneal injection of gentamicin. The expression of bFGF and FGFR1 was examined by Northern blot, in situ hybridization and immunohistochemistry. (3)H-TdR incorporation was used to detect the role of bFGF in promoting the proliferation of renal tubular epithelial cells and renal fibroblasts. RESULTS: The expression of bFGF mRNA and protein synthesis of bFGF and FGFR1 increased during the process of injury and regeneration of tubular epithelial cells. In contrast, normal tubular epithelium failed to express bFGF, except renal interstitial fibroblasts and monocytes/macrophages. bFGF promoted proliferation of renal tubular epithelium as well as renal interstitial fibroblasts. CONCLUSION: bFGF is secreted by tubular epithelial cells damaged by nephrotoxicity of gentamicin, and FGFR1 expressed in damaged renal tubules and interstitial fibroblasts. bFGF not only can promote tubular epithelia to proliferate, but can also stimulate interstitial fibroblasts to proliferate. Correlation exists between bFGF, renal tubular injury and interstitial lesions.

Animals↗
PubMed2000

[Protein kinase B and its role in the signal transduction pathway mediated by phosphoinositide 3-kinase].

Protein kinase B (PKB) is the expression product of a proto-oncongen (c-akt), which is involved in the signaling pathways initiated by some growth factors and mediated by phosphoinositide 3-kinase (PI3K). PKB is a direct target of PI3K. Similar to many protein kinases, PKB has a specific AH/PH domain which can mediate the interaction between signaling molecules. The lipid second messengers, PI-3, 4-P2 and PI-3,4,5-P3 produced by PI3K, can bind to the AH/PH domain of PKB and of PDK (phosphoinositide dependent protein kinase). This binding translocates PKB and PDK to the plasma membrane, and activates them. PKB is also activated via phosphorylation by PDK and, in turn, will activate the anti-apoptotic machinery, glucose metabolism (glycogen synthesis, glycolysis and glucose uptake) and protein synthesis. All these lead to cell growth and proliferation.

3-Phosphoinositide-Dependent Protein Kinases↗
PubMed1999

Acute activation of CD8+ T lymphocytes in interleukin-2-treated HIV-infected patients. ANRS-048 IL-2 Study Group. Agence Nationale de Recherches sur le SIDA.

CD8+ T lymphocytes play a key role in the control of HIV infection, through both cytotoxic and noncytotoxic mechanisms. To study in vivo effects of interleukin-2 (IL-2) treatment on this cell compartment, the level of activation of CD8+ T lymphocytes was evaluated before and just after 5-day administration of IL-2 in 16 HIV-infected patients. The serum level of soluble CD25 and of soluble CD8 significantly increased following IL-2 administration. The number of mRNA molecules coding for perforin and granzyme B, two enzymes that are contained in granules of cytotoxic cells, also significantly increased in peripheral blood mononuclear cells and in purified CD8+ cells (p < .001). Variations of plasma HIV viremia and perforin gene expression following IL-2 administration were inversely correlated (p = .023), suggesting that IL-2-induced activation of CD8+ T lymphocytes contributes to limit HIV replication in vivo. In contrast to perforin and granzyme B gene expression, IL-2 administration did not increase the expression of macrophage inhibitory protein-1alpha (MIP-1alpha), MIP-1beta, and regulated-on-activation normal T-expressed and secreted (RANTES) genes. These findings indicate that CD8+ T lymphocytes in HIV-infected patients are acutely activated by IL-2 treatment, which may improve long-term control of HIV infection.

CD8 Antigens↗