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Biomedical subjects

J Shen

Publications and source records attributed to J Shen.

At least 325 records · Page 18Linked to original sources

Pleural mesotheliomas have an integrin profile distinct from visceral carcinomas.

Cryosections of epithelial, sarcomatoid, and biphasic malignant mesotheliomas (EMM, n = 11; SMM, n = 5; BMM, n = 6) of the pleura were immunostained with monoclonal antibodies to integrin subunits alpha 1-6 and v, and beta 1-4. Localization patterns were compared with those known to occur in pulmonary and other adenocarcinomas (PADC, ADC). EMM and the epithelial component of BMM (ecBMM) expressed alpha 1,3,5,6, and v and beta 1 and 4. SMM and the sarcomatoid elements of BMM (scBMM) reacted variably for alpha 1,3,5,6 and v, and beta1. Reactions for alpha3, found in all tumors, were strongest in EMM, ecBMM, and PADC. Our findings indicate that EMM and ecBMM parallel PADC and most ADC in their expression of alpha6 beta4, underscoring that this laminin integrin receptor is intimately associated with these neoplastic epithelial phenotypes. Also, our observations on alpha3 beta1 suggest that this cell-cell adhesion-mediating integrin is related to the epithelial phenotype. Notably, all malignant mesotheliomas (MM), including those with distinct glandular structures, expressed the alpha5 beta1 fibronectin receptor, thus paralleling most sarcomas and differing from PADC and most other ADC. We conclude that irrespective of architectural and cytologic variants, transformed mesothelial cells possess an integrin repertory that differs significantly from that of most ADC, including those of the lung. These findings set mesothelium apart from epithelia and may prove helpful as adjunct tools for the differential diagnosis between EMM and AD.

Adenocarcinoma↗

Effects of age and gender on the AII-induced stimulation of prolactin release and inositol phosphate accumulation in rat anterior pituitary cells in vitro.

The stimulatory effects of Angiotensin II (AII) on prolactin secretion and inositol phosphate accumulation were examined in dispersed anterior pituitary cells collected from young (3-4 month), mature (7-8 month) and old (18-20 month) male and female rats. Physiological doses of AII (0.01-10 nM) stimulated prolactin release from cells collected from mature female rats only. This effect was antagonized by pretreatment with Saralasin, an AII receptor antagonist. Significant accumulation of the inositol phosphates was observed in cells obtained from the mature, female donors and this increase preceded the prolactin response. Although there was a small increase in total inositol phosphate accumulation in cells obtained from the old female rats, this was transient and did not coincide with a similar increase in prolactin release. These results indicate that pituitary sensitivity to AII stimulation is related to the age and the gender of the donor animal. The physiological role of pituitary AII needs to be examined in sexually mature female animals.

Aging↗

Role of multiple ArcA recognition sites in anaerobic regulation of succinate dehydrogenase (sdhCDAB) gene expression in Escherichia coli.

Succinate dehydrogenase (sdhCDAB) gene expression in Escherichia coli is negatively regulated by the arcA and fnr gene products during anaerobic cell growth conditions. The controlled synthesis of this sole membrane-bound enzyme of the tricarboxylic acid cycle allows optimal participation in the aerobic electron transport pathway for the generation of energy via oxidative phosphorylation reactions. To understand how ArcA participates in the anaerobic repression of sdhCDAB expression, a family of sdhC-lacZ fusions was constructed and analysed in vivo. DNase I footprint and gel shift assays using purified ArcA protein revealed the location of four distinct and independent ArcA binding sites in the sdhC promoter region. ArcA sites, designated sites 1 and 2, are centred at -205 bp and -119 bp upstream of the sdhC promoter, respectively, whereas ArcA site 3 overlaps the -35 and -10 regions of the sdhC promoter. A fourth ArcA site is centred at +257 bp downstream of the sdhC promoter. They are bound with differing affinity by ArcA and ArcA phosphate. The in vivo studies, in combination with the in vitro studies, indicate that ArcA site 3 is necessary and sufficient for the ArcA-dependent repression of sdhC gene expression, while the DNA region containing ArcA site 2 contributes to maximal gene expression. The DNA-containing ArcA sites 1 and 4 provide minor roles in the ArcA regulation of sdhC expression. Lastly, the Fnr-dependent control of sdhCDAB gene expression was shown to occur independently of the ArcA and to require DNA sequences near the start of sdhC transcription.

Bacterial Outer Membrane Proteins↗

Modelling regional population growth in China.

"This paper develops a forward demographic rates-based multiregional population model on the basis of a set of multiregional population accounts. Forward emigration rates and immigration flows are adopted to describe the external migrations. The model is used to make consistent multiregional population projections of China at a provincial level.... Three sets of multiregional population projections of China at provincial level are made for the period 1987-2087. It is found that the national population trend is a combination of various regional population trends. Some regions, such as Zhejiang, will reach their population peak as early as the beginning of the next century while other regions, such as Xinjiang, will face continuous population growth in the first half of the next century."

Asia↗

Characterization of susceptible chiasma configurations that increase the risk for maternal nondisjunction of chromosome 21.

Recent studies of trisomy 21 have shown that altered levels of recombination are associated with maternal non-disjunction occurring at both meiosis I (MI) and meiosis II (MII). To comprehend better the association of recombination with nondisjunction, an understanding of the pattern of meiotic exchange, i.e. the exchange of genetic material at the four-strand stage during prophase, is required. We examined this underlying exchange pattern to determine if specific meiotic configurations are associated with a higher risk of non-disjunction than others. We examined the crossover frequencies of chromosome 21 for three populations: (i) normal female meiotic events; (ii) meiotic events leading to MI non-disjunction; and (iii) those leading to MII non-disjunction. From these crossover frequencies, we estimated the array of meiotic tetrads that produced the observed crossovers. Using this approach, we found that nearly one-half of MI errors were estimated to be achiasmate. The majority of the remaining MI bivalents had exchanges that clustered at the telomere. In contrast, exchanges occurring among MII cases clustered at the pericentromeric region of the chromosome. Unlike the single exchange distributions, double exchanges from the non-disjoined populations seemed to approximate the distribution in the normal population. These data suggest that the location of certain exchanges makes a tetrad susceptible to non-disjunction. Specifically, this susceptibility is associated with the distance between the centromere and closest exchange. This result challenges the widely held concept that events occurring at MII are largely independent of events occurring at MI, and suggests that all non-disjunction events may be initiated during MI and simply resolved at either of the two meiotic stages.

Chromosomes, Human, Pair 21↗

Aerobic regulation of isocitrate dehydrogenase gene (icd) expression in Escherichia coli by the arcA and fnr gene products.

Isocitrate dehydrogenase, the icd gene product, has been studied extensively regarding the regulation of enzymatic activity and its relationship to the metabolic flux between the tricarboxylic acid cycle and the glyoxylate bypass. In this study, the transcriptional regulation of icd gene expression was monitored by using an icd-lacZ gene fusion and shown to vary over a 15-fold range in response to changes in oxygen and carbon availability. Anaerobic cell growth resulted in fivefold-lower icd-lacZ expression than during aerobic growth. This negative control is mediated by the arcA and fnr gene products. When different carbon compounds were used for cell growth, icd-lacZ expression varied threefold. The results of continuous cell culture studies indicated that this control may be due to variations in cell growth rate rather than to catabolite repression. DNase I footprinting at the icd promoter revealed a 42-bp ArcA-phosphate-protected region that overlaps the start site of icd transcription. Phosphorylation of ArcA considerably enhanced its binding to DNA, while ArcA-phosphate exhibited an apparent dissociation value of approximately 0.1 microM. Based on these studies, ArcA appears to function as a classical repressor of transcription by binding at a site overlapping the icd promoter during anaerobic cell growth conditions.

Acetates↗

Early E-selectin, VCAM-1, ICAM-1, and late major histocompatibility complex antigen induction on human endothelial cells by flavivirus and comodulation of adhesion molecule expression by immune cytokines.

Expression of E-selectin (ELAM-1, CD62E) on human umbilical vein endothelial cells significantly increased 30 min postinfection with the flavivirus West Nile virus (WNV), was maximal by 2 h postinfection, and declined to baseline levels within 24 h. Expression of ICAM-1 (CD54) and VCAM-1 (CD106) was significantly increased by 2 h and maximal at 4 h after infection. P-selectin (CD62P) expression was unaffected by WNV. Upregulation occurred earlier than that caused by tumor necrosis factor alpha (TNF-alpha) or interleukin 1 (IL-1) and could not be inhibited by neutralizing TNF-alpha, IL-1alpha, or alpha/beta interferon (IFN-alpha/beta) antibodies, suggesting a direct, virus-mediated phenomenon. TNF-alpha significantly enhanced WNV-induced increases in E-selectin, P-selectin, ICAM-1, and VCAM-1 expression, while IFN-gamma enhanced WNV-induced ICAM-1 expression. In contrast, IL-4 abrogated WNV-induced E-selectin expression increases but acted in synergy with WNV to increase P-selectin and VCAM-1 expression. WNV increased the expression of class I and II major histocompatibility complex antigens (MHC-I and MHC-II, respectively) at 24 and 72 h, respectively. IFN-gamma, TNF-alpha, or IL-1 acted in synergy with WNV to produce greater increases in MHC-I expression than WNV or cytokines alone, while IFN-alpha/beta or IL-4 had no effect. MHC-II induction in cytokine-treated, WNV-infected cells was similar to that caused by cytokines alone. Neutralizing IFN-alpha/beta antibody inhibited WNV-induced MHC-I expression by 30% at 24 h and by 100% by 72 h. The differential kinetics of modulation suggest sequential adhesion of leukocyte subpopulations to infected endothelial cells, which may be important in initial viral spread in vivo.

Animals↗

Polymorphic markers of the glycogen debranching enzyme gene allowing linkage analysis in families with glycogen storage disease type III.

Glycogen storage disease type III (GSD-III), an autosomal recessive disease, is caused by deficient glycogen debranching enzyme (GDE) activity. We identified three polymorphic markers in the GDE gene using single strand conformation polymorphism (SSCP) analysis and DNA sequencing. They were -10G/A in the 5' non-translated region of exon 3,2001 + 8C/T in intron 16, and 3199C/T (P1067S) in exon 25. Two polymorphic markers (-10G/A and 2001 + 8C/T) were highly informative in both controls and GSD-III patients with heterozygosity values of 0.50 and 0.46, respectively. The third marker (3199C/T) had a heterozygosity value of 0.26. Restriction analysis of the PCR amplified genomic DNA products in two GSD-III families showed for the first time the potential use of these markers for carrier detection and prenatal diagnosis in this disease.

Base Sequence↗

[Suppressive effects of a plant-origin polyol, dulcitol on collagen-induced arthritis in mice].

Dulcitol was isolated chemically from Celastrus obiculatus Thumb and determined by HPLC. Effects of dulcitol were examined on collagen-induced arthritis (CIA) in DBA/1J mice. From 6 weeks after the first immunization with bovine type II collagen, dulcitol (100 mg/kg body weight/day) was administered orally to immunized mice for 9 weeks. Clinical score of CIA was improved significantly by dulcitol intervention compared with the non-treated CIA mice. Radiographic score of phalangeal destruction was also improved by dulcitol treatment. These findings suggest that dulcitol may play a role in regulation of some inflammatory responses in the present arthritis model. Significant reduction of percentage of CD4+ and CD8+ T cell subsets in the spleen leucocytes of CIA mice was observed by flow cytometry. Almost normal level of CD4+ and CD8+ T cells was observed in dulcitol-treated groups, suggesting T cell-modifying effect of dulcitol in CIA. Weight of spleen was larger in CIA mice and it was not affected by dulcitol. Anti-collagen antibody titer was increased in CIA mice, and it was not affected by dulcitol, either. Improvement of the changes of CD4+ and CD8+ T cells in the spleen by dulcitol may suggest its modulatory effect on cellular immunity.

Animals↗

[A study on the cytotoxicity of six filling materials in vitro].

This paper deals with the cytotoxicologic analyses on 6 filling materials with morphology of cells, ultraviolet light spectrophotometry and incorporation test using mouse L-929 fibroblasts labelled 3H-TdR. The results showed that the cytotoxicity of Silver amalgam and the Gallium-Silver alloys, which were produced by mixing the conventional dental alloys powder or high copper alloys powder with Gallium, was significantly stronger than that of light curing composites and the Gallium-Silver alloys that were produced by the spherical amalgam alloys powder and Gallium. It suggested that the level of mercury and copper in the alloys can influence their cytotoxic properties.

Animals↗

[The development of a multivision glare tester].

This paper presents a new kind of multivision glare tester. Its composition, function, hardware, software and application are introduced. The tester provides a practical tool for evaluating visual function change under glare-producing conditions.

Contrast Sensitivity↗

[Chemical studies on Campylotropis hirtella (Franch. Schindl.)].

From the roots of Campylotropis hirtella 6 compounds were isolated. Based on the extensive spectrae analysis their chemical structures were identified as beta-sitosterol, oleanolic acid, ursolic acid, euscaphic acid, tomentic acid and rosamultin.

Drugs, Chinese Herbal↗

Evidence of increased endogenous carbon monoxide production in newborn rat endotoxicosis.

Carbon monoxide is thought to serve as a new endogenous mediator in the pathogenesis of sepsis and septic shock. In newborn rat endotoxicosis, carbon monoxide levels in the circulation as well as liver, kidney and lung were found to be significantly increased (P < 0.05). Moreover, the elevations of carbon monoxide correlated with enhanced nitric oxide production as indicated by nitrite/nitrate levels (P < 0.05). Our present data showed for the first time that endogenously produced carbon monoxide was increased during the course of shock-like states, which suggested that the role of carbon monoxide in sepsis and septic shock might worth further study.

Animals↗

[Interstitial tubercle in Chinese and Japanese young adults]

A comparative study on the incidence of interstitial tubercle from standardized stone casts of 160 Chinese and 190 Japanese young adults,ages from 20-30.The following results were obtained:(1)No significant difference in the incidence of interstitial tubercle on maxillary first premolar between Chinese and Japanese groups(P>0.05),but on maxillary second premolar,Japanese is higher than Chinese(P<0.05).(2)The incidence of interstitial tubercle on maxillary first premolar is higher than second premolar in two groups(P<0.05).(3)The intestitial tubercle occurs in unilateral more frequently than in bilateral.The incidence of maxillary first premolar in mesial of occlusal is higher than in distal.No difference between mesial and distal on occlusal of maxillary second premolar in the Chinese group,and the incidence in mesial is higher than in distal in the Japanese group.

Journal Article↗

[Morphological study on occlusal grove of mandibular molar of Chinese adults]

During human evolution,the morphology of mandibular molar occlusal grooves have changed from the pattern "Y" to pattern "+".Six types of occlusal grooves were classified as:Y5,Y4,+5,+5,X5 and X4. Using computer analysis,we get the result.(1)The rate of "Y5" in first mandibular molar is the highest,the rate of "X4" is the lowest.(2)The rate of "+4" in second mandibular molar is the highest,while the rate of "Y5" is the lowest. (3)The rates of each type groove between male and remale have no significant difference.Our conclusion coincides in the evolution of human mandibular molar,that is helpful to direct the clinic and anthropology study.

Journal Article↗