Biomedical subjects

Z Peng

Publications and source records attributed to Z Peng.

At least 55 records · Page 3Linked to original sources

PubMed2000

Interferon-gamma-responsive neuronal sites in the normal rat brain: receptor protein distribution and cell activation revealed by Fos induction.

Constitutive expression of the interferon-gamma receptor protein (IFN-gammaR), and the distribution of cells in which Fos, a marker of cell activation, is induced by intracerebroventricular administration of IFN-gamma, were studied in the rat brain by immunohistochemistry. IFN-gammaR immunopositivity was found in neuronal elements, which exhibited a selective distribution being concentrated in the piriform and entorhinal cortex, midline thalamus and medial hypothalamic structures, brainstem nociceptive relays (including the periaqueductal gray, the parabrachial nuclei and the caudal part of the spinal trigeminal nuclei), and circumventricular organs such as the median eminence and area postrema. IFN-gamma-induced Fos expression mostly corresponded to neuronal sites of receptor distribution. Because of its topographical distribution, it is suggested that activation of the IFN-gammaR in neurons may play a role to limit spread of infections in the brain and, in concert with other proinflammatory cytokines, to modulate adaptive responses to an antigen challenge mediated by the central nervous system.

Animals↗

PubMed2000

Hierarchical unfolding of the alpha-lactalbumin molten globule: presence of a compact intermediate without a unique tertiary fold.

The difference between the framework model and the hydrophobic collapse model of protein folding largely rests on whether a secondary-structure framework can exist independently of native tertiary interactions. Here, we used circular dichroism and disulfide exchange experiments to examine the unfolding mechanism of alpha-LA(alpha), a two- disulfide variant of human alpha-lactalbumin (alpha-LA) that adopts a molten globule conformation under near physiological conditions. Our results show that as the concentration of denaturant increases, the alpha-LA molten globule first loses its ability to form a specific, native-like tertiary fold. Subsequently, at a higher denaturant concentration, the protein loses its secondary structure and adopts an extended conformation. A compact, non-native disulfide bond isomer, which does not form significantly under both native and strongly denaturing conditions, was found to be moderately populated in approximately 2 M guanidine hydrochloride (GuHCl). Qualitatively the same result was also obtained in urea. These results suggest that formation of secondary structure is a necessary, but not sufficient condition for formation of the native-like tertiary fold and support a hierarchical model of protein folding.

Amino Acid Substitution↗

PubMed2000

Cloning and overexpression of a tyrosinase gene mel from Pseudomonas maltophila.

The tyrosinase gene (mel), which is responsible for melanin formation, was isolated by shotgun cloning of SalI fragments of Pseudomonas maltophila DNA. A 0.7-kb SalI fragment in the recombinant plasmid pWSY8 imparted the ability to synthesize melanin to an Escherichia coli host HB101. The nucleotide sequence of this DNA fragment revealed an open reading frame of 504 bp, encoding a protein of 169 amino acids. The fragment containing the mel gene was then cloned into an expression plasmid pPAS1 under the control of a promoter isolated from the host, P. maltophilia AT18. This strain increased the melanin production by 70.6% compared with the strain HB101/pWSY8, in which the cloned mel gene was under the control of the lac promoter from the vector pUC18.

Amino Acid Sequence↗

PubMed2000

Analysis of diversity and genetic relationships between four Chinese indigenous pig breeds and one Australian commercial pig breed.

The genetic diversities and relationships of four Chinese indigenous pig breeds and one Australian commercial pig breed have been evaluated using 27 microsatellites recommended by the International Society of Animal Genetics (ISAG) and the Food and Agriculture Organization (FAO). The allele frequencies, effective numbers of alleles and the polymorphic information content have been calculated. Nei's standard genetic distances have been used to construct a UPGMA dendrogram, which has been evaluated by the Bootstrap test. The utility of microsatellites for evaluating genetic diversity of pigs is discussed.

Alleles↗

PubMed2000

Ordering three microsatellites on porcine chromosome 12 by single sperm typing.

Three microsatellite loci on porcine chromosome 12 were ordered by single sperm typing to expand the limited genetic map of this region. Individual sperm cells from a Chinese indigenous Qingping boar triply heterozygous at SW874, SW1350 and SW1553 were amplified using PEP and heminesting primer design at each locus. Analysis of the sperm typing data by the SPERM.FOR program showed that the most likely order was SW1553-SW1350-SW874.

Animals↗

PubMed2000

Molecular regulation of constitutive expression of interleukin-8 in human pancreatic adenocarcinoma.

Recent studies have shown that interleukin-8 (IL-8) plays an important role in the growth and metastasis of human pancreatic cancer. In the present study, we determined the molecular regulation of constitutive IL-8 expression in human pancreatic cancer cells. Various human pancreatic cancer cell lines were incubated in vitro. Sixty-seven percent of the cell lines constitutively secreted high levels of IL-8, as determined using enzyme-linked immunosorbent assay. Consistently, these cells constitutively expressed high levels of IL-8 mRNA, as determined using Northern blot analysis. To determine the mechanisms of the high steady-state levels of IL-8 mRNA, the IL-8 half-life and transcription rate were measured. There was no significant difference in IL-8 half-life between cells expressing high and low levels of IL-8. However, higher transcription rates and increased IL-8 promoter activity were observed in the cells constitutively expressing high levels of IL-8. Detailed IL-8 promoter analysis using deletion mutation revealed that the region from -85 to -133 bp was essential for the constitutive IL-8 promoter activity. Also, point-mutation analysis indicated that mutation of NF-kappaB, AP-1, or NF-IL-6 binding sites significantly reduced or eliminated the constitutive IL-8 promoter activity. Consistent with the constitutive IL-8 transcription activity, high levels of constitutive NF-kappaB and AP-1 activity were detected in the cells overexpressing IL-8, as determined using electrophoretic mobility shift assay. In addition, transfection of a dominant-negative I-kappaBalpha expression vector (I-kappaBalphaM) inhibited constitutive NF-kappaB activity and IL-8 expression in pancreatic cancer cells. Collectively, our data demonstrated that constitutive NF-kappaB and AP-1 activation contributes to the overexpression of IL-8, which in turn plays an important role in tumor angiogenesis and contributes to the aggressive biology of human pancreatic cancer.

Adenocarcinoma↗

PubMed2000

Non-penetrating chest blows and sudden death in the young.

Sudden death in the young after low energy anterior chest wall impact is an under-recognised phenomenon in this country. Review of the literature yields several American references to commotio cordis, mainly in the context of sporting events. Two cases are reported of sudden death in young men as a result of blunt impact anterior chest wall trauma. It is suggested that these cases draw attention to a lethal condition of which many practitioners are unaware.

Adolescent↗

PubMed2000

Selective estrogenic effects of a novel triphenylethylene compound, FC1271a, on bone, cholesterol level, and reproductive tissues in intact and ovariectomized rats.

FC1271a is a novel triphenylethylene compound with a tissue-selective profile of estrogen agonistic and weak antagonistic effects. It specifically binds to the estrogen receptor alpha and beta with affinity closely similar to that of toremifene and tamoxifen. To study the in vivo effects of the compound, 4-month-old rats were sham operated (sham) or ovariectomized (OVX) and treated daily for 4 weeks with various doses of FC1271a or vehicle (orally). FC1271a was able to oppose OVX-induced bone loss by maintaining the trabecular bone volume of the distal femur. Accordingly, the OVX-induced loss of bone strength was prevented at doses of 1 and 10 mg/kg. FC1271a also prevented the OVX-induced increase in serum cholesterol in a dose-dependent manner. No significant changes in uterine wet weight or morphology were observed in the OVX-rats treated with 0.1 or 1 mg/kg FC1271a, but at a dose of 10 mg/kg it had a slightly estrogenic effect. In immature rats the effect of FC1271a on uterine wet weight was less stimulatory than that of toremifene or tamoxifen, but more stimulatory than that of raloxifene or droloxifene. The appearance of the dimethylbenzanthracene (DMBA)-induced mammary tumors was inhibited by treatment of DMBA-treated rats with FC1271a in a dose-dependent manner. In human MCF-7 breast cancer cell tumors raised in nude mice in the presence of estrogen, the growth and expression of pS2 marker gene could not be maintained after estrogen withdrawal by treatment with FC1271a. No formation of DNA adducts was observed in the liver of the FC1271a-treated rats. In conclusion, the bone-sparing, antitumor, and cholesterol-lowering effects of FC1271a combined with a low uterotropic activity and lack of liver toxicity indicate that FC1271a could be an important alternative in planning antiosteoporosis therapy for estrogen deficiency.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed2000

[Induction of apoptosis in ovarian carcinoma cells by HSP70 antisense oligodeoxynucleotides].

OBJECTIVE: To investigate the role of HSP70 in the proliferation and survival of ovarian carcinoma cells by inhibiting HSP70 expression with HSP70 antisense oligomer. METHODS: Morphological changes of apoptotic cells were investigated by light microscopy. DNA fragmentation was analysed by agarose gel electrophoresis. Kinetics of induction of apoptosis and cell cycle were analysed by flow cytometry. RESULTS: The HSP70 antisense oligomer treated ovarian carcinoma cells showed apparent inhibition of proliferation and characteristic morphological changes of apoptosis. Also, a ladder-like pattern of DNA fragments was demonstrated on agarose gel electrophoresis. HSP70 antisense-oligomer induced apoptosis of ovarian carcinoma cells mainly in G(1)/S phase in 8.3% to 41% at 1 to 20micromol/L. The apoptosis-inducting effect of HSP70 antisense oligomer was in a dose- and time-dependent manner. CONCLUSION: HSP70 antisense oligomer could not only inhibit the proliferation but also induce the apoptosis in ovarian carcinoma cells.

Apoptosis↗

PubMed2000

Progress in the molecular genetic research of multinodular goiter.

Multinodular goiter is a worldwide-distributed disease, but yet its pathology and genetic etiology are not clear. At present, most researches have been restrained to traditional epidemiological survey and the disease has been rarely studied at the level of molecular genetics. The pathogenesis of multinodular goiter, as is generally accepted by most researchers, can be attributed to many factors such as hormones, growth factors and the inherent functional heterogeneity of thyroid follicles. Since hormone and iodine metabolization are widely recognized as a major mechanism in determining the formation of multinodular goiter, some reports in literature are mainly focused on such genes that are responsible for hormone synthesis and iodine metabolization. Mapping experimental data were available to support location of multinodular goiter gene(s) onto chromosome 14q by whole genome scanning in a large pedigree analysis. Additional data, particularly those extracted from large scaled marker-assisted mapping experiments, are important so as to confirm the gene location, to improve resolution of the location, and finally to dissect the genes underlying the disease at molecular level.

Chromosome Mapping↗

PubMed2000

[The effect of polylactide screws on fracture healing].

This experiment aimed at investigating the effect of a kind of home-bred poly-DL-lactide screws on fracture healing. An operation was performed so as to make bilateral lateral condylar fractures of the femur in 8 dogs. The left sides were fixed with 2 home-bred PDLLA(Mv = 43 x 10(4)) screws, and the contralateral sides were fixed with 2 metalic screws to be used as controls. The animals were sacrificed at 2, 4, 8, and 12 weeks after surgery. Optic microscopy and SEM photography were done. The results of optic microscopy showed that fibrous callus formed already in both groups by 2 weeks after surgery, and bilateral fractures united uneventfully by 12 weeks. Although the course of fracture healing in experimental group was slower than that in control group, the osteogenesis in experimental group appeared to be normal. The SEM examination demonstrated that collagenous fibers arranged regularly and calcified normally in both groups at 12 weeks. And many square and rhomboid granules produced from the degradation of PDLLA material were found in experimental group at 12 weeks. Therefore, it is suggested that this kind of home-bred PDLLA screws should be applicable to fractures where the tissues are rich in blood supply.

Animals↗

PubMed2000

[Study on the carcinogenic mechanism of human papillomavirus typel6 E7 protein in cervical carcinoma].

OBJECTIVE: To determine the relationship between HPVl6 E7-Rb protein binding (Rb protein was dissociated from pRb-E2F-l complex) and the occurrence of cervical carcinoma. METHODS: HPV16 DNA infection rate was tested in cervical carcinoma and normal cervical tissues by polymerase chain reaction (PCR) technique. Then using Western blot analysis to find the presence HPVl6E7 protein and pRb-E2F-1 complex in HPV16 DNA positive cervical carcinoma tissues. The normal cervical tissues were used as control. RESULTS: Out of 67 samples with cervical carcinomas, 34 samples were HPV16 DNA positive (50.7%), no HPVl6 DNA were detected in 10 samples of normal cervical tissues. In cervical carcinoma tissues, the HPV16E7-pRb complex, the free E2F-1 were detected by Western blot, but no complex of pRb-E2F-l was found. CONCLUSIONS: Our results seem to suggest that HPV 16 E7 protein could interact with pRb through separating the complex of pRb-E2F-1, release free E2F- 1, resulted in disordered cell cycle and cell malignant transformation.

Blotting, Western↗

PubMed2000

[Expression of mismatch repair gene hMSH2 in human malignant ovarian tumors and its clinical significance].

OBJECTIVES: To study the expression of hMSH2 gene in human malignant ovarian tumor and its relationship to clinicopathological characteristics. METHODS: The expression of hMSH2 gene in 42 patients with malignant ovarian tumor was detected by immunohistochemistry streptomycin peroxidel method using monoclonal antibody to hMSH2 protein. RESULTS: hMSH2 expression was observed in the 26 of 42 malignant ovarian tumors (62%), more frequently present in serous and mucinous adenocarcinoma (80%, 80%) than in endometrioid adenocarcinoma and malignant germinal tumors (1/6, 1/6) (P < 0.05). It was significantly higher in high grade than in low grade (P < 0.05), and the reduced expression of hMSH2 was also significantly more often in lymphnodes metastasized cases. Statistical analysis indicated that hMSH2 expression wasn't related to the stage of the tumors. CONCLUSIONS: These results suggest that the abnormal expression of hMSH2 might be involved in the carcinogenesis process and progression of malignant tumor, and that the loss of the hMSH2 protein expression might be a useful predictor of early diagnosis and prognosis of malignant ovarian tumor.

Base Pair Mismatch↗

PubMed2000

[Clinical observation of tiaojining recipe in combination with corticosterone in infantile primary nephrotic syndrome].

OBJECTIVE: To investigate the effects of Tiaojining recipe (TJNR) combined with corticosterone (CS) in treating infantile primary nephrotic syndrome (IPNS). METHODS: Sixty inpatients with IPNS were divided into two groups, which consisted of 30 cases as the treated group treated by TJNR combined with CS and 30 cases of the control group were treated by CS alone for 8 weeks. The changes of urinary protein, serum albumin, blood cholesterol, platelet and blood pressure before and after treatment were observed. RESULTS: The total effective rate of the treated group was significantly higher than that of the control group (P < 0.01). The times for urinary protein disappearance of the treated group was significantly shorter than that of the control group (P < 0.05). Compared with the control group. TINR could prevent hypertension, lower lipidemia and platelets (P < 0.01). CONCLUSION: TJNR could enhance the curative effects of CS on IPNS and reduce the side-effects of CS safely and effectively.

Child↗

PubMed2000

[The effect of pentoxifylline on endotoxin-induced biopterin formation in rabbits].

OBJECTIVE: To observe the potential effect of pentoxifylline on endotoxin-mediated biopterin (tetrahydrobiopterin and more oxidized species) formation and systemic hemodynamics. METHODS: Rabbits were subjected to endotoxic shock induced by a bolus intravenous injection of E. coli O26B6 lipopolysaccharide (400 microg/kg). 28 animals were divided into sham-operation group (n = 8), endotoxic shock group (n = 10), and pentoxifylline-treated group (n = 10). Plasma biopterin and tumor necrosis factor-alpha (TNF) levels, and guanosine triphosphate cyclohydrolase I (GTP-CHI) activity in tissues were determined at various intervals. RESULTS: Treatment with pentoxifylline significantly decreased plasma biopterin and TNF levels at 2 to 8 hours after endotoxin challenge (P < 0.05, P < 0.01), and inhibited GTP-CHI activities in the liver, lung, and myocardial tissues (P < 0.05). Meanwhile, systemic hemodynamic parameters, including mean arterial pressure, cardiac output, and total peripheral resistance, in the treatment group were much higher than those in the endotoxic shock group. CONCLUSIONS: These data suggest that early treatment with pentoxifylline can effectively inhibit endotoxin-induced biopterin synthesis and release, and markedly improve systemic hemodynamics during septic shock.

Animals↗

PubMed2000

[A study on the epidemiology and preventive measure on epidemic haemorrhage fever in army barrack area in Shandong].

OBJECTIVE: In order to guide the army and civilians to carry out the prevention on epidemic haemorrhage fever (EHF), it's necessary to elucidate the epidemic feature of natural epidemic foci and the risk factors of EHF in the army - stationed areas. METHODS: Samples were tested by pathogenic and serologic means before data was collected and analyzed by case - control or family - control studies. RESULTS: Cases belong to house - mouse type (91.48%), field - mouse type (7.21%) and unclassified (1.31%) coexist in the stationed area. In the two types of noticed cases, no significant difference in distributions of sex, profession and ages. Most house - mouse type cases occurred in the peak time from March to June and field - mouse type in November to next February. The type of EHF virus antigen of mice and the type of serum were both accordant with their host types. Dwelling in border area, living rooms with mice, dogs raising, injury of mouth tissue, eating food contaminated by mice, and household with mice living around were more frequently seen in cases themselves and in families of the cases than in controls of both groups (P < 0.05). The mice intensity could be under control to 1.0%, if comprehensive measure on mice control can be implemented. CONCLUSIONS: The stationed area is an epidemic area mixed with both house - mouse and field - mouse types, with majority of house - mouse type. It was house - mouse type virus infection that caused the epidemic area expanded and the number of cases increased radically these years. EHF was epidemic in spring and summer season in the stationed area mainly because the infections were among family members. Food contaminated by mice or close contact with mice played an important role. Mice eradication and prevention were the leading measures to prevent EHF, from our more than ten years of experiences.

Adult↗

PubMed2000

[Study of estrogen and progesterone receptors in endometrial carcinoma].

This study was conducted to immunohistochemical and biochemical measurements of estrogen receptor (ER) and progesterone receptor (PR) in endometrial carcinoma and elucidate the relationship between ER/PR contents and the clinico-pathologic features. Specific monoclonal antibodies to human ER and PR were used and the immunohistochemical (IHC) assay was performed on 36 specimens of endometrial carcinomas. Twenty-eight out of 36 specimens' ER and PR contents were also measured by dextran-coated charcoal analysis (DCC). ER and PR positive rates were 44.4% and 52.8% by IHC, and 50% and 57.1% by DCC, respectively. The two methods correlated significantly, the correlation coefficient between DCC and IHC being 0.565 for ER and 0.563 for PR (P < 0.05). ER and PR contents were much lower in grade 3 than in grades 1 and 2 endometrial carcinomas (P < 0.01). The authors conclude that the levels of ER and PR are associated with the differentiation of endometrial carcinoma. The immunohistochemical and biochemical methods correlate well. A combination of the two methods may be more useful in predicting the prognosis and choosing the treatment.

Adenocarcinoma↗

PubMed2000

[The effect of intraperitoneal chemotherapy on retroperitoneal lymph node metastasis of ovarian cancer].

The objective of this study was to investigate the effect of intraperitoneal chemotherapy(repeated injections of cisplatin in small doses during a short time) on retroperitoneal lymph node metastasis of ovarian cancer. Thirty patients with ovarian cancer were selected and divided into two groups. The patients in the first group received intraperitoneal chemotherapy only once (48 hours before operation); the patients in the second group received intraperitoneal chemotherapy twice (96 hours and 48 hours before operation). After the intraperitoneal chemotherapy, according to the predicted time, the Pt concentrations of the tissues were measured by flameless atomic absorption spectrometry; the pathologic examinations of the lymph nodes were carried out. The results showed that the drug concentrations of the aortic, obturator and iliac lymph nodes of the first group were not significantly different, neither were the drug concentrations of the lymph nodes of the second group. The drug concentrations of the lymph nodes of the first and the second groups were 2.06 and 1.91 times that of the surrounding tissues respectively. Also, the drug concentrations of peritoneum of the first and the second groups were 4.14 and 2.50 times that of the lymph nodes. The drug concentrations of the iliac, obturator and aortic lymph nodes of the second group were 2.27, 2.75 and 2.54 times that of the first group (P < 0.005). Under light microscope, the metastatic cancer tissues in lymph nodes showed liquefaction necrosis in the second group. The results indicate that small doses of cisplatin given by repeated injections during a short time can lead to drug accumulation and consequently high efficacy with low toxicity, suggesting that this method may be used for the treatment of lymphatic metastasis of ovarian cancer.

Antineoplastic Agents↗