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Biomedical subjects

J Zhu

Publications and source records attributed to J Zhu.

At least 667 records · Page 37Linked to original sources
PubMed1995

Cytomegalovirus infection induces expression of 60 KD/Ro antigen on human keratinocytes.

To investigate the effect of human cytomegalovirus (CMV) infection on the expression of Ro autoantigen in human keratinocytes, the binding of anti-Ro peptide antibodies (anti-60 KD/Ro, anti-52 KD/Ro and anti-calreticulin) to cultured human keratinocytes was detected by fixed cell enzyme-linked immunoassay (ELISA), immunofluorescence, flow cytometry (FACS) analysis and immunoblotting. There was a significant increase in the binding of anti-60 KD/Ro antibody but not anti-52 KD/Ro or anti-calreticulin antibody to the surface of cultured keratinocytes at 24 h after CMV infection compared with uninfected cells, by ELISA and immunofluorescence. Surface binding of anti-60 KD/Ro was found in 71.2% (+/- 5.5%) of CMV-infected cells compared with 26.2% (+/- 4.1%) of untreated cells (P < 0.05) by FACS analysis. Similar observations were made with a human serum which contained anti-60 KD/Ro antibodies. Immunoblotting was used to analyse total cellular 60 KD/Ro antigen expression in keratinocytes infected with CMV or without infection. No increase in the intensity of the 60 KD band was found in extracts of the CMV-infected cells, suggesting that the 60 KD/Ro antigen is redistributed from the cytoplasm to the cell surface after viral infection. The effects of CMV infection on cell cultures were compared with those of ultraviolet B (UVB) irradiation. The 60 KD/Ro, 52 KD/Ro and calreticulin were all induced on the UVB-irradiated cell surface but not significant synergistic effect of UVB and CMV was found. This study provides evidence that CMV infection induced 60 KD/Ro antigen expression on the surface of human keratinocytes, suggesting that CMV may play a role in development of skin lesions in systemic lupus erythematosus (SLE).

Amino Acid Sequence↗
PubMed1995

Differential display of messenger ribonucleic acid: a useful technique for analyzing differential gene expression in human brain tumors.

In this study, a differential display method for messenger ribonucleic acid was successfully used to identify genes differentially expressed between normal human brain and malignant glioma tissues. A total of 60 differentially expressed sequences were initially identified, of which 21 were cloned and sequenced. Twenty of the cloned sequences represented novel genes, and one sequence represented a kinesin heavy chain (KHC) gene isoform. The KHC isoform was selected for further characterization. Northern blots of total ribonucleic acid isolated from normal brain and a glioblastoma were probed with our KHC probe and confirmed the differential expression of this gene. Expression analysis of a variety of normal human tissues demonstrated that this KHC isoform is expressed only in brain tissues, with no detectable expression in placenta, spleen, kidney, lung, liver, or skeletal muscle. Our results confirm the rapid and sensitive nature of the differential display technique in identifying differential gene expression. This method offers a means to identify new genes of biological interest in human brain tumors such as oncogenes, tumor suppressor genes, and tumor-specific markers.

Adult↗
PubMed1995

Identification of a novel Ca(2+)-regulated protein that is associated with the marginal band and centrosomes of chicken erythrocytes.

We have identified a novel Ca(2+)-regulated protein, p23, that is expressed specifically in avian erythrocyte and thrombocyte lineages. Sequence analysis of this 23 kDa protein reveals that it bears no homology to any known sequence. In mature definitive erythrocytes p23 exists in equilibrium between a soluble and a cytoskeletal bound pool. The cytoskeletal fraction is associated with the marginal band of microtubules, centrosomes and nuclear membrane under conditions of low free [Ca2+]. An increase in free [Ca2+] to 10(-6) M is sufficient to induce dissociation of > 95% of bound p23 from its target cytoskeletal binding sites, yet this [Ca2+] has little effect on calmodulin-mediated MB depolymerization. Analysis of p23 expression and localization during erythropoiesis together with results from heterologous p23 expression in tissue cultured cells demonstrated that this protein does not behave as a bone fide microtubule-associated protein. In addition, the developmental analysis revealed that although p23 is expressed early in definitive erythropoeisis, its association with the MB, centrosome and nuclear membrane occurs only in the final stages of differentiation. This cytoskeletal association correlates with marked p23 stabilization and accumulation at a time p23 expression is being markedly downregulated. We hypothesize that the mechanism of p23 association to the MB and centrosomes may be induced in part by a decrease in intracellular [Ca2+] during the terminal stages of definitive erythropoiesis.

Amino Acid Sequence↗
PubMed1995

Novel centrosomal protein reveals the presence of multiple centrosomes in turkey (Meleagris gallopavo) bnbn binucleated erythrocytes.

The phenotype of the bnbn hemolytic anemia mutation in the domestic turkey is manifested as binucleation specifically in the definitive erythrocyte lineage, most likely as the consequence of anomolous centrosomal activity (Bloom et al., 1970; Searle and Bloom, 1979). Here we have identified in turkey two variants of the novel, centrosomally-associated erythroid-specific protein p23. One variant is Ca(2+)-sensitive and is highly homologous to its chick counterpart (Zhu et al., 1995, accompanying paper). The other, p21 is a truncated form resulting from a 62 amino acid deletion from the 3' end and a 40 amino acid insertion at the 5' end, and appears to lack Ca(2+)-sensitivity. These proteins are localized at the marginal band, centrosomes and nuclear membrane of differentiated erythrocytes. Anti-p23/p21 immunofluorescence revealed the presence of multiple centrosomes in bnbn erythrocytes. We therefore undertook a detailed genetic analysis to determine whether the p21 variant represented the bn mutation. Initial tests of normal BnBn and mutant bnbn individuals suggested that the p23/p21 proteins might be encoded by the Bn/bn genes. However, further genetic tests demonstrated independent segregation for these two genetic loci. Thus, these proteins are encoded by the heretofore undescribed genes, p23/p21, mapping to an autosomal locus in the turkey genome.

Amino Acid Sequence↗
PubMed1995

Influence of ion channel modulation on in vitro interferon-gamma induced MHC class I and II expression on macrophages.

The in vitro effect of K+ channel blockers quinidine and verapamil, anion channel blocker SITS and K+ channel openers diazoxide, pinacidil, and BRL 38227 on interferon-gamma (IFN-gamma) induced MHC class I and II expression of Lewis rat peritoneal macrophages was investigated by cell ELISA assay. MHC class I expression was significantly enhanced by diazoxide at concentrations of 10(-5)M to 10(-6)M and by pinacidil and BRL 38227 at the concentration of 10(-6)M. MHC class II expression was enhanced by pinacidil and BRL 38227 at concentrations of 10(-5)M to 10(-6)M. The enhancing effect of pinacidil could be blocked by inhibitors of the protein kinases PKA and PKC suggesting that activation of both is required for optimum induction of MHC molecule expression. K+ and anion channel blockers were less active in modulation of MHC molecule expression. Verapamil had no influence, quinidine suppressed MHC class I expression at concentrations of 10(-4)M to 10(-5)M, and SITS suppressed MHC class I expression at the concentration of 10(-3)M. Since MHC class II expression is essential for efficient antigen presentation to T helper cells and MHC class I expression is required for target cell lysis by cytotoxic T cells, ion channel modulating drugs may be potential candidates for immunopharmacological intervention in inflammatory diseases.

Animals↗
PubMed1995

Survey of major histocompatibility complex class II haplotypes in four turkey lines using restriction fragment length polymorphism analysis with nonradioactive DNA detection.

Four turkey lines were typed for MHC Class II haplotypes with restriction fragment length polymorphism (RFLP) analysis using a nonradioactive probe made from a chicken genomic clone of MHC Class II genes. The RFLP analysis detected 18 new patterns in the populations. There were three new haplotypes that had a frequency of about 10% or more in a population, whereas the rest appeared only once. The haplotype frequencies were significantly different in the E line, selected only for increased egg production, and the F line, selected only for increased body weight, compared with their respective randombred control lines. The shift of haplotype frequencies in the two selected lines seemed to be in opposite directions. One, but not the same, haplotype predominated in the selected lines, with about 50% of total haplotypes. Fewer haplotypes were frequent in the selected lines, whereas the frequencies in the control lines were relatively widely distributed, with the most frequent haplotype being below 35%. The frequency of homozygotes of the Class II haplotypes was the highest in the F line.

Animals↗
PubMed1995

Neuropeptide Y (18-36) modulates chromaffin cell catecholamine secretion by blocking the nicotinic receptor ion channel.

Neuropeptide Y (NPY) is a widely distributed peptide with varied activities including inhibition of [3H]NE secretion from chromaffin cells. In the present study, we investigated the mechanism through which NPY and NPY fragments inhibit nicotinic receptor induced influx of 22Na+ and 45Ca++ into bovine chromaffin cells. Fragments of NPY, including NPY13-36, NPY18-36 and NPY26-36, are more potent inhibitors of 45Ca++ and 22Na+ influx than NPY. High [K+]- and BAY K 8644-induced 45Ca++ influx and veratridine-induced 22Na+ influx are not inhibited by either NPY or NPY fragments. Thus, the site of NPY or NPY fragment action is not voltage-gated Ca++ or Na+ channels. A significant amount of acetylcholine-induced 45Ca++ influx still occurs in the presence of the voltage-gated Ca++ channel blockers: nifedipine (L-type), omega-conotoxin-GVIA (N-type) and omega-agatoxin-IVA (P-type). NPY18-36, in the presence of these channel blockers, inhibited the residual nicotinic receptor-induced Ca++ influx. The response to NPY 18-36 is not pertussis toxin sensitive. The rank orders of potency for inhibition of 45Ca++ and 22Na+ are the same: NPY18-36 > or = NPY26-36 > NPY13-36 > NPY13-36 > NPY > or = NPYfree acid. Moreover, the IC50 values for NPY18-36 inhibition of 45Ca++ influx and 22Na+ influx are similar, 0.9 x 10(-6) M and 2.03 x 10(-6) M, respectively. Regression analysis for inhibition of these two phenomena produced a correlation coefficient of .9697 (P < .0003).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[Transrectal hyperthermia in the treatment of benign prostatic hyperplasia].

A group of 53 patients with benign prostatic hyperplasia underwent transrectal hyperthermia using Prostathermer (Biodan) from September 1992 to March 1993. 41 of the 53 patients were followed up for 6 months. The subjective symptoms improved in 75.6% (31/41) of the treated patients. The mean maximum urine flow rate increased by 3.1 +/- 2.6 ml/s. The mean residual urine reduced 38.4 +/- 25.2 ml. The mean prostate volume remained almost unchanged. The results showed that transrectal hyperthermia of the prostate gland is as effective as transurethral approach for the treatment of benign prostatic hyperplasia.

Aged↗
PubMed1995

[Bone histomorphometry study in post-menopausal women with osteopenia].

OBJECTIVES: To investigate the histological features of bone, the turnover status of bone remodeling in postmenopausal women with osteopenia. To observe the influence of age on the changes of bone turnover. METHODS: Two hundred ninety three bone biopsies were obtained from posterior iliac crests of postmenopausal white women with osteopenia after taking fluorescence-labelled tetracyclin. All these specimens were embedded in methacrylate, the nondecalcified sections were stained routinely and measured by computerized histomorphometry. RESULTS: The mean trabecular bone volume was 10.6% +/- 5.47%, which is 29.3% less than the low limit of normal range (15%) established in our laboratory. There were 186 cases (63.5%) in normal turnover status, 75 cases (25.6%) in high turnover, and 32 cases (10.9%) in low turnover. In comparison with the normal turnover group, the osteoclast number, corrected bone mineralization rate and bone formation rate were elevated and mineralization lag time was reduced in the high turnover group (P < 0.01). In contrary, all the above parameters in the low turnover group were on the opposite (P < 0.05-0.01). Comparison of three age groups (51-60, 61-70, > 70 years) showed that the bone volume and osteoid volume decreased as the age increased. The proportion of high and low turnover types began to increase in the 51-60 age group, peaked in the 61-70 age group and dropped to nadir in the > 70 age group. CONCLUSIONS: Bone histomorphometry examination is not only valuable in distinguishing osteoporosis from osteomalacia, but also beneficial for determination of the bone turnover status and, therefore, is useful for the direction of clinical treatment in patients with postmenopausal osteopenia.

Aged↗
PubMed1995

Interaction of silkworm larvae expressed monomeric hM-CSF with its receptor on murine bone marrow derived macrophage.

Human macrophage colony-stimulating factor (hM-CSF) expressed in the silkworm larvae was monomeric. The nature of the interaction of iodinated monomeric M-CSF with murine bone marrow derived macrophage (BMM) was studied. On incubation with 2 nM [125I]M-CSF at 4 degrees C, approximately 90% of the maximal binding occurred within 15 min with a plateau around 1hr which then gradually declined. Scatchard plot analysis showed that the Kd for the monomeric M-CSF is 5.3 x 10(-10) M and the number of binding sites per cell is 4 x 10(4). Competition experiment indicated that cellular binding of the iodinated monomeric rhM-CSF was almost as effective as the native M-CSF. The results show that the interchain disulfide bond of M-CSF is not essential for the natural folding of active M-CSF.

Animals↗
PubMed1995

Acute intra-abomasal toxicity of tannic acid in sheep.

Acute tannic acid toxicity was studied in 6 adult Merino ewes by administering 7-10% (w/v) tannic acid solution once into the abomasum via an abomasal fistula at dose rates of 0.5, 1.0 or 2.0 g tannic acid/kg body weight. Samples of blood, urine and abomasal fluid were collected over a 48-h period before the sheep were necropsied 48 h after dosing. Dose rates of 1.0 and 2.0 g tannic acid/kg body weight produced abomasal, liver and kidney lesions. The abomasum had superficial mucosal erosions, hemorrhage and submucosal edema; the liver showed midzonal or periacinar coagulative necrosis; and the kidneys had focal tubular vacuolation and necrosis. In sheep dosed with 1.0 g tannic acid/kg body weight, there was a significant (P < 0.01) decrease in plasma phosphate and an increase in plasma aspartate aminotransferase and urea levels. Plasma total protein concentrations significantly (P < 0.05) decreased 24 h after dosing, but returned to normal by 48 h. By 4 h after dosing, abomasal fluid pH was significantly (P < 0.01) higher than predosing value, whereas urine pH significantly (P < 0.05) decreased. Both abomasal fluid and urine pH returned to normal 48 h after dosing. The liver and kidney damage seen in this study, in contrast to the methemoglobinemia without liver and kidney lesions previously reported when sheep were given tannic acid by oral gavage (1), suggest that, in cases of natural poisoning, tannins are not released from plant material until it enters the abomasum.

Abomasum↗
PubMed1995

Assessing intratumor distribution and uptake with MBBG versus MIBG imaging and targeting xenografted PC12-pheochromocytoma cell line.

UNLABELLED: The heterogeneity of tumor uptake is likely to substantially limit the effectiveness of metaiodobenzylguanidine (MIBG) therapy. This study was done to establish whether metabromobenzylguanidine (MBBG) can target neuroendocrine tumors and to provide intratumor biodistribution and uptake information in comparison to MIBG. METHODS: MBBG and MIBG tumor uptake and kinetic studies were performed in experimental PC-12 pheochromocytoma grown in nude mice. Intratumor distribution studies were performed using autoradiography and secondary ion mass spectrometry (SIMS) microscopy, because the latter technique can detect and potentially quantify both drugs concomitantly within the same tumor specimen. RESULTS: MBBG uptake in PC12 tumors was early (2 hr) and intense (80% ID/g). Retention values were similar for both drugs 24 hr postinjection. At the cellular level, MBBG mostly accumulated in the cytosol. At the multicellular level, cells exhibited staining, but in many areas, SIMS images of both drugs were not spatially correlated. CONCLUSION: MBBG targeted experimental pheochromocytoma efficiently with high early uptake values. Bromine-76-MBBG is a promising means of imaging and quantifying tumor uptake with PET. Both drugs were localized in the cytosol, but the correlation between the two distributions, as assessed by the values of the standardized local concentrations, was weak although significant multicellularly.

3-Iodobenzylguanidine↗
PubMed1995

[3 retinoic acid isomers on proliferation and differentiation properties of APL cell line-NB4].

We examined the effect of three RA isomers, including ATRA, 13C-RA and 9C-RA, on the proliferation and differentiation properties of NB4 cells, a cell line established from APL patient and carrying the typical translocation t (15;17). Standard parameters such as cell morphology, cell growth curve, dynamics of cell cycle, expression of clusters of differentiation and reduction of nitro blue tetrazolium (NBT) were used to evaluate the effects of the three isomers. During the first 48 hours of RA treatment, the APL cell maturation was coupled with the cell proliferation. Moreover, significant differences of differentiation-induced effect among RA isomers were observed. ATRA showed better results than 13C-RA while 9C-RA functioned even better than ATRA. These data are helpful to understand the mechanisms, by which RAs induce promyelocytic leukemia cell differentiation and open a new prospect for the clinical use of novel retinoic acid isomers.

Cell Division↗
PubMed1995

[Hemofiltration ameliorating reperfusion injury after complete cerebral ischemia: an experimental study].

The effects of hemofiltration on cerebral resuscitation were studied by using resuscitation model of potassemia-induced cardiac arrest and cardiopulmonary bypass. Sixteen rabbits were divided into control group (CG) and hemofiltration group (HFG). Blood lactic acid, lipid peroxidant (LPO), serum iron, middle molecular substance (MMS) were determined. Neurologic deficit score (NDS) system was used to evaluate neurologic function. The level of blood lactic acid was increased in both CG and HFG. It was higher in CG than in HFG (P > 0.05). Serum iron was increased in CG, however, it was decreased in HFG. The difference between the two groups was significant (P < 0.01). LPO was increased significantly in CG and there was no obvious changes in HFG. MMS was increased gradually during reperfusion in CG, whereas it was decreased in HFG. There was significant difference in the corresponding times of the two groups. NDS of CG was higher than that of HFG (32 +/- 12 vs 18 +/- 10) (P < 0.01). These data demonstrate that hemofiltration is able to eliminate ischemic and reperfusional toxic products quickly. Additionally, free iron, agonist factor of catalyzing free radical reaction, does not increase because free radicals and lactic acid are eliminated quickly, inhibiting free radical tissue injury and improving cerebral resuscitation.

Animals↗