Search PubMed⌕ Search

Biomedical subjects

C H Zhang

Publications and source records attributed to C H Zhang.

At least 55 records · Page 3Linked to original sources
PubMed1994

[Effects of NG-nitro-L-arginine and reduced hemoglobin on endothelium-dependent relaxation of mesenteric artery in SHRsp].

It was verified in our previous study that endothelium-dependent relaxation (EDR) in the mesenteric artery strip of adult spontaneously hypertensive rats (SHR and SHRsp) was decreased upon addition of acetylcholine (ACh). In order to explore further the mechanism of this decrease of EDR, the effects of NG-nitro-L-arginine (L-NNA) (a NO synthase inhibitor) and reduced hemoglobin (RHb) (a scavenger of EDRF) on this ACh EDR were investigated in both stroke-prone SHR (SHRsp) and control WKYs. Our results showed that the difference of EDR (ACh 10(-8)-10(-5) mol/L) between SHRsp and WKY disappeared in the presence of L-NNA (10(-3) mol/L), but addition of RHb (10(-5) mol/L) would abolish such a difference only at ACh 10(-7)-10(-8) mol/L. In comparison to changes of EDR (ACh 10(-8)-10(-5) mol/L) between post L-NNA and post RHb in WKY and in SHRsp, no significant difference was found in WKY, but significant difference was found in SHRsp. And also, it appeared that the sensitivity of intact endothelium mesenteric artery of SHRsp to RHb was similar to WKY, but that to L-NNA is lower than that of WKY. Consequently it is considered that in the attenuation of EDR in hypertensive visceral vessels, the EDRF mechanism and endothelial L-arg-NO pathway are not identical.

Animals↗
PubMed1994

[Planned delivery by oxytocin infusion in relation to cephalic dystocia].

To investigate the effect of initiating labor by oxytocin infusion on the outcome of delivery in cephalic presentation, the dystocia rate and final modes of delivery were analyzed in 3,090 cases of head presentation using oxytocin infusion and 2,982 cases with spontaneous onset of labor as control group. The results showed that 562 of the cases using oxytocin developed cephalic dystocia, a rate of 18.2%, while 371(12.4%) of the control group had dystocia. Besides, cephalic dystocia, rates of episiotomy, vacuum extraction and cesarean section were all significantly higher in the oxytocin group than those in the control (P < 0.005). Data also showed that the higher dosage, the more frequency and the longer time of pitocin infusion the higher the rate of dystocia.

Dystocia↗
PubMed1994

[Relation of HSP70 gene and spontaneously hypertension in rats].

The level of heat shock protein 70 messenger RNA was examined in aortic smooth muscle cells (ASMC) and hepatic tissue of Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). The restriction fragment length polymorphism (RFLP) was also analysed in hepatic DNA. It was demonstrated that the basic level of heat shock protein 70 messenger RNA in ASMC and hepatic tissue of SHR were lower than that of the WKY rats. The extent of heat shock protein 70 messenger RNA accumulated in ASMC was higher in SHR than in WKY rats when the cells were heated by immersing the culture bottles in 42 degrees C water bath for 15 min and allowed to recover at 37 degrees C for 2 h. In contrast with WKY rats, the Bam HI restricted bepatic DNA showed that a fragment about 5.6 kb was lost in heat shock protein 70 gene from hepatic DNA of SHR. The results suggest that the ASMC of SHR is more sensitive to heat stress than that of WKY rats and the changes of heat shock protein gene sequence may be related to genetic hypertension.

Animals↗
PubMed1994

[Transcription of HSP 70 gene induced by pressure overload in left ventricule of rats].

The changes of heat shock protein 70 (HSP70) messenger RNA was examined in rats after abdominal aortic partial ligation. Four hours after ligation, the systemic arterial pressure was increased and thereafter maintained at a high level. The ratio of left ventricule weight to body weight began to increase at the third day and increased by 59%, comparing with that of the sham-operated rats at 4 w. Accumulation of HSP 70 mRNA was observed at 4 h and maintained at high level at 1 d, 2 d, 1 w and then gradually disappeared there after. The above experimental results suggest that transcription of HSP 70 gene was induced at an early stage of cardiac hypertrophy caused by pressure overload.

Animals↗
PubMed1993

Gene expression of Na+/Ca2+ exchanger in brain ischemia.

It is known that intracellular Ca2+ is overloaded during ischemia as a result of the altered activity of the Na+/Ca2+ exchanger, one of the major pathways of Ca2+ efflux. But the molecular mechanism of the alteration is still unknown. We cloned a -500bp cDNA fragment of rat cerebellar Na+/Ca2+ exchanger gene. Using this cDNA fragment as the probe, we found that the Na+/Ca2+ exchanger mRNA is widely distributed in rat central and peripheral nervous system such as in cerebra, heart, lung and kidney. Using focal cerebral ischemic model, we detected the gene expression of Na+/Ca2+ exchanger in ischemic brain by Northern bolt and in situ hybridization, and found that in ischemic tissues, the mRNA level of Na+/Ca2+ exchanger is lowered.

Animals↗
PubMed1993

[Analysis of 24 cases of misdiagnosed orbital tumors with visual impairment as the presenting symptom].

24 cases of orbital tumors misdiagnosed as optic neuritis or optic atrophy were located at the orbital apex or on the optic nerve, comprising meningioma 9 cases, cavernous hemangioma 5 cases, neurilemmoma 5 cases, neogrowths form the nasal cavity or paranasal sinuses 3 cases, leiomyoma 1 case and hemangiopericytoma 1 case. The authors analyzed the causes of CT examination in early differential diagnosis.

Adolescent↗
PubMed1992

[Histopathologic study on lymphadenopathy in HIV infected patients].

Histopathologic study on the lymphadenopathy of 38 HIV infected patients in Zambia are reported. The histologic type of lymph node changes might be divided as follows: follicular hyperplasia, mixed follicular hyperplasia, follicular involution, and lymphocyte depletion. The author points out that although each individual histologic change in lymph node is not specific, the summation of changes in lymph node are characteristic. A diagnosis of HIV infection might be considered, and appropriate test is warranted, when histologic changes are found in enlarged lymph nodes at two or more noningunal sites for several months. Lymph node biopsy is recommended and significant in discovering HIV infected cases, making diagnosis of AIDS as well as AIDS-related complex, and evaluation of prognosis of these patients.

AIDS-Related Complex↗
PubMed1992

Preparation and in vitro antiviral activity of liposomes of lipophilic esters of acyclovir.

The long chain acyclovir such as the acyclovir laurate and acyclovir palmitate were prepared directly from acyclovir by application of the usual esterification methods with appropriate acyl chlorides. The lipophilic prodrugs were found to be retained easier by liposomes whereas acyclovir escaped readily from liposomes. When assayed in African green monkey cell cultures against herpes simplex virus type I strain, the acyclovir palmitate liposomes proved to be more active compared with the parent drug and its liposome, suggesting an enhanced compatibility between the ester and liposomal lipids and an increased uptake of encapsulated prodrug by infected cells.

Acyclovir↗
PubMed1991

[Decrease in the concentration of tobramycin, vancomycin and phenobarbital in administration with infusion filter].

To assess the loss of drugs to in-line filters, concentrations of tobramycin, vancomycin, and phenobarbitone were determined in vitro in samples recovered upstream and downstream of the filter. Binding of the drugs to new filters was higher than to used filters. With bolus administration, the concentrations of vancomycin and phenobarbitone were reduced by 1% when using old filters and by 4% when using new filters. Tobramycin concentrations were reduced by 7 and 12%, respectively. With continuous administration of the drugs, binding was highest during the first half hour. Differences between new and used filters were also seen with continuous administration: The cumulative loss was 5% higher with new than with old filters. This difference in binding between filters may stem from a saturation of free binding sites. Tobramycin showed the highest binding to the in-line filter. The extent of adsorption of tobramycin to intravenous filters may be considered moderately important in adult patients. The adsorption of vancomycin and phenobarbitone is not clinically relevant in adult patients.

Adsorption↗
PubMed1990

Invasive equine trophoblast expresses conventional class I major histocompatibility complex antigens.

Monoclonal antibodies and alloantisera were used in an indirect immunohistochemical assay to determine the expression of class I and class II Major Histocompatibility Complex (MHC) antigens by equine placental cells and the endometrial tissues at the fetal-maternal interface. MHC class I antigens were expressed at high density on the surface of the trophoblast cells of the chorionic girdle at days 32-36, just prior to their invasion of the endometrium. The mature gonadotrophin-secreting cells of the endometrial cups, which are derived from the chorionic girdle cells, had greatly reduced levels of MHC class I antigen expression while no MHC class I antigens were detectable on the non-invasive trophoblast cells of the allantochorion, except in small isolated patches. MHC class I antigens immunoprecipitated from chorionic girdle cells with either monoclonal antibodies or alloantisera had a relative molecular mass of 44,000, which was identical to that of MHC class I antigens precipitated from lymphocytes with the same reagents. MHC class II antigens were not detected on any trophoblast cells, although they were expressed at high levels by the endometrial glandular and lumenal epithelium immediately bordering the endometrial cups. MHC class I antigens were also expressed at high levels by endometrial tissues in the area of the cups. The high level of MHC class I antigen expression by endometrial glands within and bordering the cups was in sharp contrast to the greatly reduced class I antigen expression by the mature endometrial cup cells themselves.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Effects of the preparation of xiao long ling on experimental prostatic hyperplasia in mice].

The results of the experiments indicate that the prostatic hyperplasia caused by Testosteroni Propionatis in mice, cotton oil-induced local swollen ears of mice and the proliferation of granuloma produced by subcutaneous implantation of cotton pill in rats are inhibited significantly by the preparation of Xiao Long Ling. Xiao Long Ling depresses the increase of vascular permeability induced by a variety of inflammatory media such as histamine, 5-HT and PGE. Xiao Long Ling is found capable of inhibiting the platelet aggregation induced by ADP as well as depolymerizing the aggregated platelets.

Animals↗
PubMed1989

[Further studies on the mongolian jird model of Giardia lamblia].

Seventy-seven Meriones unguiculatus were inoculated intra-esophageal with Giardia lamblia cysts isolated from the stool of a Giardia infected child. Correlation between oral dosage, course of infection, trophozoite distribution and the pathological changes in the small intestine of the infected jirds were studied. One (12.5%) of eight animals became infected with only 5 cysts. 10(4) cysts/jird or more was infective to nearly all the animals. Most of the infected animals (83%) excreted cysts and/or trophozoites intermittently. The extent of trophozoite colonization and their distribution in the small intestine varied with the time of infection, but not with the number of Giardia found in the feces. There was no direct correlation between the size of inoculum and the course of infection, the fecal output of cysts and/or trophozoites, or the intensity of pathological changes in the small intestine. The histopathological lesions induced by G. lamblia included cellular infiltration of the mucosa of the small bowel, nodular lymphoid hyperplasia, edema of the lamina propria and increase in mucous secretion. Necrobiosis and shedding of the epithelium was evident, and the mitotic figures of intestinal crypt increased significantly. The reduction of the villi to crypts ratio may indicate that the villi of small intestine were covered by relatively immature enterocytes, which may, partially, account for the malabsorption in giardiasis (Figs. 1-3).

Animals↗
PubMed1988

Estimating a treatment effect under biased sampling.

Methods are presented for the estimation of a treatment effect based on before- and after-treatment values, where for ethical reasons all and only those patients are treated whose before-treatment values exceed a given constant.

Mathematics↗
PubMed1988

At least two loci encode polymorphic class I MHC antigens in the horse.

Six monoclonal antibodies and ten alloantisera were used to precipitate cell surface molecules of approximately 44 kDa (class I MHC antigens) from radiolabelled equine peripheral blood lymphocytes. All ten antisera were raised against antigens of a single donor horse (horse 0834, ELA-A2,-A2). Four methods of producing antisera were compared: one or two pregnancies, skin allografting, and skin grafting followed by pregnancy. Immunization by pregnancy appeared to produce antibodies against class I products only, while skin grafting raised antibodies to class II antigens as well. Nine of the antisera were raised across an entire MHC haplotype barrier, while one recipient carried the ELA-A2 antigen of the donor. The pregnancy antiserum raised across this barrier probably identifies a second polymorphic class I locus in the horse. Sequential immunoprecipitation using this antiserum in the first stage and an anti-MHC haplotype antiserum or monoclonal antibody reagent in the second stage supported this hypothesis. Gene products of this second ELA class I locus are immunogenic in pregnancy.

Animals↗
PubMed1988

[Pathologic study and prognostic factors in 28 patients with ovarian immature teratoma].

28 patients with ovarian immature teratoma were studied pathologically. Neoplasms with other germ cell elements were excluded. The ages ranged from 11 to 38. 71% were women under 25 years. Each primary tumor and metastatic lesion was graded histologically according to the criteria of Norris. Of these 28 cases, 11 were grade I; 11 grade II; and 6 grade III. The study showed that the stage of primary tumor is closely related to the prognosis. The likelihood of recurrence and metastasis could be determined by the grade of the primary tumor. The recurrence rate of grade I, II, and III were 0%, 44% and 100%, respectively. It also showed that the addition of hysterectomy and contralateral adnexectomy for grades II and III lesions did not improve the survival. One patient had been operated for 3 times to remove recurrences in the abdominal cavity and liver in a period of 25 months. The first and second recurrent tumors were grade III, but the third one was grade II showing that the immature teratoma tends to mature, but this conversion needs time. The authors support the opinion that repeated operations to remove the recurrences may improve the survival.

Adolescent↗