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Biomedical subjects

X Zhou

Publications and source records attributed to X Zhou.

At least 559 records · Page 31Linked to original sources
PubMed1997

[Liquid chromatographic separation of pepsinogens].

In this work, we reported a method for the purification of pepsinogens from human gastric mucosa with high pressure gel filtration chromatography (HPLC) and medium pressure anion exchange chromatography (MPLC). First, the two fractions of Pg1 and mixture of PGI and PGII were separated from pepsinogens with HPLC on a Bio-Sil SEC-125 column within 50min. Then the mixture of fractions of PGI and PGII was further separated with MPLC on a Bio-Scale Q2 column within 30min.

Chromatography, High Pressure Liquid↗
PubMed1997

Simulation study of the interaction between respiration and the cardiovascular system.

Many studies have been done on the respiratory and the cardiovascular system. Among them, only a few are on the interaction of these two physiologic systems. To explore the mechanism of the integration of these two physiological systems, computer simulation has been done; we report the preliminary results obtained in our laboratory. In this study, a mathematical model of the cardiovascular system integrated with the respiratory mechanical system has been established. The model is based on our previous work on cardiovascular modeling. The previous lumped lung model has been replaced by a multielement model with more detail. Interthoracic and abdominal pressures and modeled as external pressure sources on the related cardiovascular elements. Using this model, a sequence of simulation studies have been carried out. Different respiratory modes have been simulated and the different effects are observed in the simulation results. The results indicate that by following a certain respiratory pattern, the circulation status can be improved. These results agree with clinical observations.

Cardiovascular Physiological Phenomena↗
PubMed1997

Expression of antimetastatic gene nm23-H1 in epithelial ovarian cancer.

OBJECTIVE: To investigate the expression of nm23-H1 in epithelial ovarian cancer. METHODS: A total of 55 specimens from patients with epithelial ovarian cancers, 15 patients with serous cancers, 7 with mucinous cancers, 17 with endometrioid cancers and 16 with adenocarcinomas, were examined for the expression of nm23-H1 by means of the immunohistochemical technique. RESULTS: The total positive rate was 23.64% (13/55). The tissular nm23-H1 immunostaining had significantly higher expression in mucinous cancer (57.14%) than in other histologic types of epithelial ovarian cancer (P < 0.05). Compared to that in the primary tumor, nm23-H1 expression in the omental metastatic tumor in the same patient was reduced. CONCLUSIONS: The expression rate of nm23-H1 is higher in the primary tumors than in the metastatic tumors and is different in various histologic subtypes of epithelial ovarian cancer. The expression of nm23-H1 may participate in the inhibitory process of tumor invasion.

Adenocarcinoma↗
PubMed1997

Polymorphisms of vitamin D receptor gene and its association with bone mineral density and osteocalcin in Chinese.

OBJECTIVE: To explore the distribution frequencies of vitamin D receptor (VDR) gene polymorphisms in Chinese and the relationship between VDR genotypes and bone mineral density (BMD) or serum osteocalcin level in Chinese women. METHODS: Polymorphisms of VDR gene were analyzed by polymerase chain reaction (PCR) to amplify the DNA sequence and three restriction enzymes (namely BsmI, ApaI and TaqI) to digest the PCR products in 223 subjects. Some of the VDR genotypes were also confirmed by Southern hybridization analysis. BMD was measured at the spine and proximal femur by dual-energy X-ray absorptiometry (DEXA). Serum osteocalcin concentrations were determined by radioimmunoassay. RESULTS: Chinese had high frequencies of "b,a,T" alleles, 95%, 75% and 95% respectively, which were much different from Caucasians. "BB" or "AA" genotype had tendency for higher BMD at some sites in the group of young women, whereas in the group of postmenopausal women, "bb" or "aa" genotype had relationship with lower BMD at femoral neck and trochanter. Furthermore, no relationship were found between VDR genotypes and the serum osteocalcin level in Chinese women. CONCLUSIONS: Allele frequencies of VDR gene in Chinese are different from those in Caucasians. VDR gene polymorphisms are associated with BMD in Chinese, but in a different pattern from other reports. Further study on predicting function of VDR for osteoporosis is necessary.

Adult↗
PubMed1997

[Analysis of the causes of neonatal deaths at term in pregnancy induced hypertension patients].

OBJECTIVE: To study the neonatal developmental status, its causes of death and their possible correlation in women complicated with pregnancy induced hypertension (PIH). METHODS: 46 autopsies of neonatal death at term with PIH and their clinical data were collected. The developmental status was evaluated by body weight, body length, and the weights of lungs, kidneys, liver and brain. The causes of death were reviewed by the clinicopathologic findings. RESULTS: The neonatal development features for mild PIH in term pregnancy approached to the normal levels of 37 to 38 gestation weeks. In the infants with moderate and severe PIH, the body weights, the weights of lungs and liver were significantly decreased in comparison with those of the mild PIH, respectively (P < 0.05), while the weights of kidneys and brain were not significantly decreased. The causes of death showed that pulmonary hypoplasia accounted for 23.9%, primary pulmonary atelectasis 10.9%, pulmonary hyaline membrane disease 21.7%, massive pulmonary hemorrhage 13.0%, the meconium aspiration 19.6% and others 10.9%. There was no difference in sex among the dead infants. CONCLUSIONS: The PIH syndrome had retarded the process of fetal growth and development, and associated with the severity of PIH, mostly involving the lung and the liver. The pulmonary hypoplasia and immaturity were the primary causes for neonatal death in PIH women.

Cause of Death↗
PubMed1997

[The relationship between the pathologic features of the uninvolved endometrium and prognosis in postmenopausal endometrial carcinoma].

OBJECTIVE: To investigate the relationship between the pathologic features of the uninvolved endometrium and prognosis in postmenopausal endometrial carcinoma. METHOD: The clinicopathologic features of 204 cases of endometrial carcinoma were analyzed retrospectively, according to the proliferative and atrophic uninvolved endometrium, a long term follow-up was done. RESULTS: The patients with proliferative uninvolved endometrium (PUE) were more much related with the clinical risk factors than those of atrophic uninvolved endometrium (AUE) (P < 0.001). AUE cases had more virulent types of nonendometrial carcinoma than those of PUE (27% vs 5.5%, P < 0.001), and had much worse grade, much deeper myometrial invasion and much vascular invasion (P < 0.001). The overall 5-year survival rate was 96.7% in the PUE cases and 86.2% in the AUE cases (P < 0.001). CONCLUSION: The histopathologic types of the uninvolved endometrium were related to the prognosis of the patients with endometrial carcinoma. The patients with proliferative uninvolved endometrium had better prognosis than those with atrophic uninvolved endometrium.

Adenocarcinoma↗
PubMed1997

[Expression of the integrin alpha 5 subunit in hepatocellular carcinoma].

OBJECTIVE: To elucidate the roles of integrins in tumorigenesis, progression, differentiation, invasiveness and metastasis, and the role of the integrin alpha 5 subunit in hepatocellular carcinoma (HCC). METHODS: 79 formalin-fixed sections of hepatocellular carcinoma (HCC) were obtained. The integrin alpha 5 subunit was measured by immunohistochemistry assay (ABC method). RESULTS: In 79 cases of HCC, cancerous tissues had lower expression than their adjacent non-tumor tissues (32.9% vs 81.0%, P < 0.01). The alpha 5 positive rate in small HCC (= < 5 cm in diameter) was higher than large HCC > 10 cm in diameter), being 55.6% and 10.0% respectively. Well-differentiated HCC expressed higher alpha 5 than poorly differentiated ones. The alpha 5 positive rates were lower in highly invasive HCC than those to low invasive ones. CONCLUSION: Our study indicated that expression of the integrin alpha 5 subunit is correlated with growth, differentiation, invasiveness and metastasis of HCC. It is possible that alpha 5 subunit is a negative regulator to these biological parameters of HCC.

Adult↗
PubMed1997

[Changes of calcitonin reserve function in patients with primary osteoporosis].

In order to study the role of calcitonin (CT) in osteoporosis, the calcium loading calcitonin stimulated test (calcium element 3 mg/kg body weight, i.v., 10 min) was used to investigate calcitonin reserve function in 21 women with osteoporosis. The sesults were compared with those in 48 healthy women and 7 women with osteopenia. After calcium infusion, there was no significant difference in the basal CT, the peak CT value, the CT increase range, and the area under the curve (AUC) between pre- and post-menopausal healthy women. In patients with primary osteoporosis, the four parameters were significantly lower than those in normal controls, and the CT peak value and increase range were lower than those in patients with osteopenia. In the osteopenia group, the basal CT value and its AUC were lower than those in the age-matched control group, but no difference was found in the peak CT value and the increase range between the two groups. The results showed no evident effect of menopause on calcitonin reserve function, but suggested a possible relationship between the decrease of CT reserve function and osteoporosis in patients with osteoporosis. Calcitonin deficiency has something to do with the development of osteoporosis.

Aged↗
PubMed1997

[Analysis of familial aggregation of chronic obstructive pulmonary diseases].

Data from 206 pairs of nuclear family members were analyzed to study the influence of genetic factors on the occurrence of chronic obstructive pulmonary disease (COPD) and its familial aggregation. Results showed that occurrence of COPD appeared in family aggregation. Risk of occurrence of COPD in the relatives (father, mother, brothers and sisters) of the proband with COPD increased by 2.07 times, as compared with relatives of the controls. Significant differences of the risk of COPD in fathers, brothers and sisters between proband and controls were observed, but not in mothers. It suggests relatives of the proband are more susceptible to COPD than those of the controls, and genetic factor may contribute to pathogenesis of COPD.

Air Pollution, Indoor↗
PubMed1996

The inactive pT181 initiator heterodimer, RepC/C, binds but fails to induce melting of the plasmid replication origin.

Staphylococcus aureus plasmid pT181 replicates via a rolling circle mechanism. The synthesis of the pT181 initiator protein (RepC) is regulated by antisense RNAs, and RepC is inactivated after usage by the attachment of an oligonucleotide to one of its subunits. The inactivated heterodimeric RepC/C* has been shown be unable to initiate replication in vitro (Rasooly, A., and Novick, R. P. (1993) Science 262, 1048-1050). The inactive RepC/C* has been found to be very stable and constitute about 90-95% of the total RepC antigen inside the cell. We studied the specific interaction of the RepC/C and RepC/C* complex with the pT181 double strand origin. The results indicated that RepC/C and RepC/C* footprint supercoiled DNA differently although their footprints on linear DNA are similar; we also find that RepC/C is able to enhance cruciform extrusion while RepC/C* cannot. RepC/C* binds and bends the double strand origin much more weakly than does RepC/C. These results suggest that the attached oligonucleotide induces a conformational change in the RepC/C* molecule that is responsible for its lack of activity.

Bacterial Proteins↗
PubMed1996

Infrequent DPC4 gene mutation in esophageal cancer, gastric cancer and ulcerative colitis-associated neoplasms.

Homozygously Deleted in Pancreatic Cancer 4 (DPC4), a recently identified candidate tumor suppressor gene, was previously shown to be altered in human pancreatic cancers. We examined DPC4 mutation in 30 examples of three other types of gastrointestinal malignancy: 10 esophageal cancers, 10 gastric cancers and 10 colorectal cancers occurring in the preneoplastic condition, ulcerative colitis. The entire coding region of DPC4 (including all 11 exons) was analysed by either direct sequencing of PCR product or the in vitro synthesized protein assay. No coding region mutations of DPC4 were found in any of the samples examined. Our results suggest that inactivation of DPC4 may not be important in the majority of these types of gastrointestinal cancer.

Colitis, Ulcerative↗
PubMed1996

Neutrophil cathepsin G is specifically decreased under vitamin A deficiency.

Vitamin A deficiency leads to an increased susceptibility to infections, increased severity of infections and increased mortality. Because the neutrophil is the first cell to respond to infection, this study explores the effect of vitamin A deficiency on neutrophil proteinases. We found that neutrophils from vitamin A-deficient rats had lower levels of two cathepsin G-like enzymes (28 and 24 kDa) when compared to neutrophils from weight-matched pair-fed rats, vitamin A-deficient rats which were repleted with retinyl palmitate and nonrestricted vitamin A complete diet rats. The 28 kDa cathepsin G-like enzyme, which migrated with the same mobility as elastase on SDS-polyacrylamide gels, was quantified using Western blots. The 24 kDa cathepsin G-like enzyme was quantified using zymogram gels. This activity was inhibited by chymostatin. Other neutrophil proteinases, elastase, plasminogen activators and gelatinase, were not altered significantly by vitamin A deficiency. The low levels of cathepsin G may contribute to differences in the inflammatory process observed under vitamin A deficiency.

Animals↗
PubMed1996

Basic fibroblast growth factor (FGF-2) affects development of acoustico-vestibular neurons in the chick embryo brain in vitro.

The effects of basic fibroblast growth factor (FGF-2) on presumptive auditory and vestibular neurons from the medulla were studied in primary cell cultures. The part of the rhombic lip that forms nucleus magnocellularis (homologue of the mammalian anteroventral cochlear nucleus) was explanted from white leghorn chicken embryos at Hamburger-Hamilton stage 28 (E5.5), the time when precursors of the magnocellularis bushy cells migrate and begin to differentiate in situ. In vitro the neuroblasts migrated onto 2-D substrates of purified collagen, differentiated, and expressed neuronal markers. One-half of the cultures were supplemented with human recombinant FGF-2 (10 ng/ml daily) for 5-7 days; the others, with fetal bovine serum. FGF-2 more than doubled the length of neurite outgrowth during the first 3 day treatment compared to serum, but the number of migrating neuroblasts was unaffected. Although neurites attained greater lengths in FGF-2, they usually degenerated after 4-5 days; in serum their growth continued for several weeks. Differentiation of neuronal structure, including axons and dendrites, began within 1-2 days in bFGF but required at least 5-7 days in serum. Histochemical observations in vitro and in situ with antibodies to FGF receptor demonstrated immunopositive patches on acoustico-vestibular neuroblasts at stage 28, when they are migrating and first forming their axons. The findings suggest that FGF-2 stimulates neurite outgrowth in the cochlear and vestibular nuclei. FGF-2 may accelerate cell death by overstimulating neuroblasts, but other factors are needed to sustain their further development.

Analysis of Variance↗
PubMed1996

P2X purinoceptors in cultured myenteric neurons of guinea-pig small intestine.

1. Fast excitatory postsynaptic currents (fEPSCs) and responses to exogenously applied purinoceptor agonists were studied in primary cultures of myenteric neurons from guinea-pig small intestine. Whole-cell and outside-out configurations of the patch clamp technique were used. Hexamethonium (100 microM) partly inhibited fEPSCs in 28% of neurons. Hexamethonium-resistant fEPSCs were inhibited by 97 +/- 2% by the P2X receptor antagonist, pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid (PPADS, 10 microM). 2. ATP caused two types of inward currents. In 92% of neurons (n = 123), ATP caused a slowly desensitizing current that declined with a double exponential time course (tau 1 = 7.1 +/- 2.0 s; tau 2 = 57 +/- 7.4 s, n = 4). The rank order potency for purinoceptor agonists in these neurons was ATP > 2-methylthio-ATP (2-MeSATP) > > alpha, beta-methylene ATP (alpha, beta-me ATP) > beta, gamma-meATP > ADP. The EC50 values for ATP and 2-MeSATP were 40 and 65 microM, respectively. alpha, beta-MeATP acted as a partial agonist at these receptors. In 8% of neurons (n = 11), ATP-induced currents desensitized rapidly with a double exponential time course (tau 1 = 0.13 +/- 0.015 s; tau 2 = 2.2 +/- 1.3 s, n = 4); alpha, beta-meATP caused similar responses in these cells. Both types of ATP-induced current were associated with an increased conductance and an inwardly rectifying I-V relationship (Erev = 10 mV). Halving [Na+]o shifted the reversal potential of ATP currents by -22 +/- 6 mV. 3. ATP activated single channel currents in outside-out patches. The single channel I-V relationship was linear between -120 and 60 mV (Erev approximately 0 mV). Single channel conductance between -100 and -60 mV was 25 +/- 2 pS. Single channel open probability was voltage dependent and decreased from 0.05 +/- 0.01 at -100 mV to 0.007 +/- 0.002 at +40 mV. 4. These data show that P2X purinoceptors mediate some fEPSCs in cultured myenteric neurons. Myenteric neurons express the fast-desensitizing alpha, beta-me ATP-sensitive subtype of P2X receptor that has the properties of cloned P2X1 receptors and is similar to native receptors in smooth muscle cells. Myenteric neurons also express a P2X receptor that desensitized slowly and was alpha, beta-meATP-insensitive. This receptor has the properties of cloned P2X2 or P2X5 receptors and is similar to native receptors found in PC-12 cells and superior cervical ganglion neurons. The known distribution of P2X2 and P2X5 receptors suggests that myenteric neurons are likely to express predominantly P2X2 receptors.

Adenosine Diphosphate↗
PubMed1996

Genomic structure and expression of the murine Hmgi-c gene.

The murine Hmgi-c gene, a member of the Hmgi gene family, contains five exons encompassing >110 kb of genomic DNA at the pygmy locus on mouse chromosome 10. Northern analysis identified a 4.1 kb transcript which contains a 324 bp open reading frame encoding a 12 kDa HMGI-C protein. Further analysis defined both the 5' and 3' untranslated regions of the Hmgi-c mRNA species as 658 and 2967 bp respectively. The HMGI-C protein has three consecutive AT hook DNA binding domains and an acidic domain, each of which are encoded by individual exons; such an organization is conserved among the HMGI gene family members from insects to mammals. Similar to the HMGI/Y proteins, the HMGI-C protein does not function as a typical transcriptional activator. Developmental studies revealed that the Hmgi-c gene is expressed predominantly during mouse embryogenesis. Since the human homolog is disrupted in a number of tumors, HMGI-C could play an important role in cell proliferation and differentiation during mammalian development.

Amino Acid Sequence↗
PubMed1996

Late ischemic preconditioning is mediated in myocytes by enhanced endogenous antioxidant activity stimulated by oxygen-derived free radicals.

The primary objective of the study was to test the hypothesis that oxygen radical during initial anoxia stimulate endogenous antioxidant activity in late preconditioning in myocytes. Isolated rat myocytes were preconditioned in one group with two cycles of 5 minutes of anoxia and 5 minutes of reoxygenation and in another group with exogenous superoxide anion (.O2-) generated by reaction of xanthine oxidase with xanthine. Myocytes were kept for 24 hours, after which they were exposed to 60 minutes of anoxia and 60 minutes of reoxygenation. Preconditioned myocytes exhibited decreased LDH release, reduced malondialdehyde formation, increased cell viability, and well-preserved cell structure. .O2- production was increased in myocytes immediately after treatment with repetitive anoxia (1.65 +/- 0.08 nmol/mg protein) or exogenous .O2- (1.42 +/- 0.11 nmol/mg protein). Allopurinol, a xanthine oxidase inhibitor, abolished .O2- production during the initial preconditioning period. Twenty-four hours later, Mn SOD activity declined in anoxic control myocytes (0.38 +/- 0.06 U/mg protein), whereas it increased significantly in myocytes preconditioned with repetitive anoxia (3.25 +/- 0.15 nmol/mg protein) or with exogenous .O2- (2.27 +/- 0.10 nmol/mg protein). The increase in Mn SOD activity and myocardial protective effects observed in preconditioned myocytes were totally blocked by allopurinol. These results indicate that oxygen radicals generated during the initial preconditioning period activate endogenous antioxidant defense (increased Mn SOD activity) 24 hours later, which contributes to the late cardioprotection of preconditioning.

Animals↗