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Biomedical subjects

G Zhang

Publications and source records attributed to G Zhang.

At least 595 records · Page 33Linked to original sources
PubMed1994

Stable and temperature-sensitive transformation of rat kidney epithelial cells suppresses expression of acidic fibroblast growth factor 1 but activates secretion of fibroblast growth factor 3 (int-2) and vascular endothelial growth factor.

Rat kidney proximal tubule epithelial cells (RPTE) in primary culture express acidic fibroblast growth factor 1 (FGF-1). Transformation of RPTE by SV40 (SV-RPTE) suppressed FGF-1 expression but activated secretion of FGF-like factor(s). SV-RPTE conditioned medium contained growth-promoting activity for SV-RPTE and human umbilical vein endothelial cells, indicating that both autocrine and angiogenic factors were secreted. Reverse transcriptase-polymerase chain reaction and Northern analysis for various FGFs showed that only FGF-3, also known as int-2, mRNA was expressed in SV-RPTE. In addition, expression of mRNA for the heparin-binding angiogenic factor vascular endothelial growth factor (VEGF) increased dramatically in SV-RPTE. Physical characterization of the activity in the SV-RPTE conditioned medium suggested that FGF-3 and VEGF contributed the autocrine and angiogenic activities, respectively. We also investigated FGF-3 and VEGF secretion in temperature-sensitive (ts) SV40-transformed RPTE. tsSV-RPTE had transformed properties resembling those of SV-RPTE only at the permissive temperature (33 degrees C), e.g., increased growth potential and anchorage-independent growth. FGF-1 was expressed only at the nonpermissive temperature. VEGF mRNA levels and secretion of the human umbilical vein endothelial cell growth-promoting activity were reduced by switching tsSV-RPTE cells from 33 degrees to 39 degrees C. However, FGF-3 mRNA levels were not affected significantly by the temperature switch suggesting that activation of VEGF and FGF-3 occurs through different mechanisms. These results indicate that FGF-1 expression in RPTE is suppressed by SV40 transformation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Prevalence of HIV and HCV among injecting drug users (IDUs) in Yunnan, China].

Prevalence of HIV and HCV was studied among 507 IDUs in Yunnan Province. The results reveal that sharing needles with other IDUs is one of the primary pathways to transmit both HIV and HCV. The rates of HIV and HCV infection in the IDU group is 66.5% and 94.9% respectively, which is significantly higher than those in the non-IDU group. There is a direct correlation between the rates of HIV and HCV antibody positive. 97.5% HCV (+) subjects are also HIV (+); and 57% HIV (+) subjects are HCV (+). It is suggested that all IDUs should be encouraged to stop using drugs to prevent HIV and HCV transmission.

Adult↗
PubMed1994

[Clinical application of neurovascular island flap in the hand].

From 1962 to 1992, four kinds of neurovascular island flaps of the hand were used for the treatment of skin defects in the hand in 72 cases. Of these flaps, 38 were pulp flaps of the finger, 24 were based on the first dorsal metacarpal artery, 7 were from second dorsal metacarpal artery and 3 were from hypothenar area. All the flaps survived except 1. Postoperative follow-up showed excellent or good results in 94.4%. The indications of the operation, flap design and surgical procedure are described. The anatomical feature, the advantages and disadvantages of the flap are discussed.

Adolescent↗
PubMed1994

Experimental diabetic renal growth: role of growth hormone and insulin-like growth factor-I.

We have compared the kidneys of two inbred strains of rats (Lewis and Lewis-Dwarf) 7 days after the induction of diabetes mellitus with streptozotocin, in order to examine the influence of a selective growth hormone (GH) deficiency on diabetic renal growth and insulin-like growth factor-I (IGF-I) content of the kidneys. Insulin-like growth factor-I (IGF-I) content of the kidneys. Insulin-like growth factor-I was measured by radioimmunoassay and its distribution within the kidney by immunohistochemical staining. We detected a significant increase in both the wet weight (32.9 +/- 5.3%, P = 0.0085) and dry weight (16.3 +/- 6.3%, P = 0.046) of the kidneys of diabetic Lewis rats but dwarf rats, selectively deficient in GH, did not show a significant increase in either parameter. Extractable IGF-I increased within the kidneys of diabetic rats of both strains but to a lesser extent in the dwarf rats (+105 +/- 28% and +65 +/- 21% respectively, P < 0.01). In diabetic Lewis rats a positive correlation was noted between the severity of glycaemia and kidney IGF-I content (r = 0.604, P < 0.05) but no such correlation was noted in dwarf rats. Inulin-like growth factor-I immunostaining increased in diabetic rats of both strains, mainly within cells of the thick ascending limb of the loop of Henle including damaged and vacuolated cells. However, morphometric analysis of the staining showed that it was significantly less widespread in the diabetic dwarf rats (P = 0.026).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Restrictive fragment length polymorphism analysis of gamma-crystallin in congenital cataract families].

Using gamma-crystallin gene probe P5G1, we investigated the RFLP in two large families of congenital cataracts and normal people, calculated the allelic gene frequency and defined the haplotypes by genetic linkage analysis. In accordance with foreign reports, TaqI/p5G1 detected 3 polymorphic sites, and the allelic gene frequency was close to that in foreign reports. However, foreign reports claimed that the haplotype P was linked to Coppock cataracts, but we did not find such linkage by haplotype analysis. The result suggests that not all the inherited cataracts are linked to gamma-crystallin gene, and the haplotype P should not be simply regarded as genetic marker in prenatal diagnosis.

Cataract↗
PubMed1994

[The case-control study of hepatitis risk factors in Shashi City].

Hepatitis was regarded as a main health problem in Shashi city, Hubei province, according to DSP data at present. The case-control study of hepatitis risk factors were carried out among 115 hepatitis cases and 60 controls that all were negative serologically in Shashi city. The result indicates that economic status, way of having breakfast outside, habits of washing hands before meals and after feces, levels of knowing about route of infection of hepatitis are independently associated with morbidity probability of hepatitis A, the comprehensive preventive measures are presented in the light of these conclusions.

Case-Control Studies↗
PubMed1993

Purification, characterization, and cellular localization of the 100-kDa human placental GTPase-activating protein.

Human placenta contains, in addition to the ubiquitous p120-GTPase-activating protein (GAP), another isoform of 100 kDa, which is specific to this organ. We have established a method for purifying this placental p100-GAP to near homogeneity. The purified p100-GAP allowed the preparation of polyclonal and monoclonal anti Ras-GAP antibodies. Two monoclonal antibodies were selected for a two-site enzyme immunoassay. This simple and accurate assay in turn facilitated the detection of the GAPs during purification. The purified p100-GAP has a specific activity identical to and catalytic properties similar to those of native p120-GAP. Sequence analysis of p100-GAP revealed almost total identity to the known corresponding sequences predicted by the cDNA. The purified p100-GAP kept its activity for 1 year when stored at -80 degrees C. Our immunometric assay showed GAP to be present in human placental extracts at the exceptional abundance of about 0.1% of the total protein content. Quantitative assays showed p100-GAP to be up to 10 times more abundant than p120-GAP. Use of our antibodies allowed the specific localization of placental GAPs to cytotrophoblasts and in the syncytiotrophoblast barrier. Hence p100-GAP is shown to be found only in trophoblasts. The large quantity of p100-GAP in trophoblasts suggests that it may play a regulatory role in the proliferation or the differentiation of this cell type.

Amino Acid Sequence↗
PubMed1993

Ethanol inhibits tetraethylammonium chloride-induced synaptic plasticity in area CA1 of rat hippocampus.

Dendritic recordings of the rat hippocampal formation were used to assess the ability of ethanol to inhibit the induction of synaptic plasticity due to bath application of the K+ channel blocker, tetraethylammonium chloride (TEA). Brief application of TEA resulted in the enhancement of the population excitatory postsynaptic potential (EPSP) slope by an average of 26 +/- 3% over the pre-TEA baseline. However, coapplication of TEA and ethanol (100 mM) resulted in enhancement of only 10 +/- 2% of the EPSP slope. These data suggest that LTP (long-term potentiation) due to the activation of voltage-gated Ca2+ channels is also inhibited by ethanol.

Animals↗
PubMed1993

A role for fibroblast growth factor type-1 in nephrogenic repair. Autocrine expression in rat kidney proximal tubule epithelial cells in vitro and in the regenerating epithelium following nephrotoxic damage by S-(1,1,2,2-tetrafluoroethyl)-L-cysteine in vivo.

The regenerating proximal tubule epithelium in the rat has striking similarity with rat kidney proximal tubule epithelial cells (RPTE) in primary culture (Wallin, A., Zhang, G., Jones, T. W., Jaken, S., and Stevens, J. L. (1992) Lab. Invest. 66, 474-484). We used this in vitro model to investigate mechanisms which may regulate aspects of nephrogenic repair in vivo, and in particular the role of fibroblast (heparin-binding) growth factor type-1 (FGF-1) expression. FGF-1 was present predominantly as a 14.3-kDa polypeptide in rat kidney. Biological activity and mRNA for FGF-1 increased dramatically in primary RPTE in culture along with an increase in a 18.3-kDa FGF-1. Cycloheximide blocked FGF-1 expression in primary culture indicating that the increase represents newly synthesized factor rather than release from the extracellular matrix. The maximal increase in expression occurs after the peak of RPTE proliferation. Activity was not present in the medium but intracellular FGF-1 was released from RPTE by scrape wounding. Immunohistochemical analysis showed that FGF-1 expression increased in regenerating proximal tubule epithelial cells 5 days after nephrotoxic damage. Collectively, the data suggest that autocrine expression of FGF-1 by regenerating proximal tubule epithelial cells plays a role in the regulation of nephrogenic repair.

Animals↗
PubMed1993

Alterations of muscle activities and jaw movements after blocking individual jaw-closing muscles in the miniature pig.

Although the inactivation or removal of motoneurones and muscles are known to affect development and growth of the craniofacial skeleton and masticatory muscles, the effect of these on functional activity patterns is not clear. The goal of this study was to evaluate the immediate responses of masticatory muscle activities to temporary nerve blocks of individual jaw-closing muscles. Nineteen experiments were made with four miniature pigs (Sus scrofa). Electromyograms of the masticatory muscles and jaw movements were recorded during natural chewing. Then, the function of individual jaw-closing muscles was removed unilaterally by local anaesthesia, and the recording repeated. The results showed a general increase in the activities of the other jaw-closing muscles, particularly those that were synergistic with the blocked muscle in producing lateral movements. Furthermore, the lateral pterygoid showed stronger activity, and accordingly the lateral movement was increased. Digastric muscle activity and the magnitude of jaw opening also tended to increase. Thus, the response to loss of a muscle is a strong, immediate compensation by synergists.

Animals↗
PubMed1993

Value of transrectal ultrasound in identifying local disease after radical prostatectomy.

Transrectal ultrasound was performed on 15 men with clinical suspicion of local disease after radical retropubic prostatectomy. Clinical suspicion was defined as an elevation in serial serum prostate-specific antigen (PSA, above 0.4 ng/mL, Tandem-R + Assay) and/or palpable mass in the rectal vault. Post-radical prostatectomy ultrasound was normal if there was smooth tapering of the bladder neck to the urethra with no foci of variable echogenicity, and suspicious if any hyper- or hypo-echoic foci were present or if a mass was detected. Thirteen of 15 ultrasounds (87%) were described as suspicious while 2 of 15 (13%) were described as normal. Only 6 of 13 patients (46%) with suspicious findings on ultrasound had biopsy-proved carcinoma. Both patients with normal findings on post-radical prostatectomy ultrasound had biopsy-proved cancer. Transrectal ultrasound of the prostatic fossa when used independently is of no value in the diagnosis of local disease after radical prostatectomy. Transrectal ultrasound may help to direct systematic biopsies of the prostatic fossa in those patients in whom local disease is suspected on the basis of elevated serum PSA and/or a mass found on rectal examination.

Adenocarcinoma↗
PubMed1993

Extra-adrenal perirenal myelolipoma.

Extra-adrenal perirenal myelolipomas are rare benign tumors that consist of adipose and hematopoietic tissue. We report a case of perirenal myelolipoma in an otherwise healthy man and review the literature.

Aged↗
PubMed1993

Complete nucleotide sequence of a coxsackie B5 virus and its relationship to swine vesicular disease virus.

We report the first complete nucleotide sequence of the picornavirus coxsackievirus B5 (CB5), strain 1954/UK/85, an isolate from a case of hand-foot-and-mouth disease. We have compared the sequence with those of other coxsackie B viruses, coxsackievirus A9, poliovirus and swine vesicular disease virus (SVDV). The genes encoding the three major capsid proteins are most closely related to those of SVDV but the 5' and 3' noncoding regions and the P3 gene are more similar to the corresponding regions in the other coxsackie B viruses than to those of SVDV. These observations are considered in the light of the antigenic and biochemical relationships between SVDV and CB5.

Amino Acid Sequence↗
PubMed1993

CT and pathological study on radiofrequency-induced lesion in cat thalamus.

In order to observe the postoperative focal changes caused by radiofrequency lesions in the ventrolateral nucleus of the thalamus in stereotactic treatment of Parkinson's disease, similar lesions were produced in cat. The CT features and their correlative pathologic changes at different intervals were divided into three types, four stages and three zones. The degree of susceptibility of nervous tissue to radiofrequency, repair characteristics and the mechanism of CT enhancement are discussed in light of the pathologic changes.

Animals↗
PubMed1993

Compartmentalization in the pig latissimus dorsi muscle.

Portions of the latissimus dorsi (LD) muscle are frequently employed as free muscle or myocutaneous grafts. The functional consequences for both the graft and the remaining donor tissue must depend in part on the neural organization of the muscle. Previous anatomical and clinical reports have suggested that the LD is organized into independently innervated segments, but experimental documentation has been lacking. This study investigated the neural organization of the LD in pigs using (1) synchronous electromyography (EMG) of several sites within the LD and motion analysis of the shoulder and forelimb, and (2) dissection and stimulation of the primary branches of the thoracodorsal nerve, followed by histochemical analysis, to delineate the areas innervated by each. The findings indicated that while there is minor overlap between adjacent segments, the LD can be considered as consisting of three semi-independent compartments. Further, the teres major is linked to the LD functionally as well as anatomically, so that the two muscles can be considered as a four-part complex.

Animals↗
PubMed1993

Effects of oral sensory afferents on mastication in the miniature pig.

The performance of mastication is presumed to be influenced by afferent stimulation, but little information is available from awake, intact animals. Thirteen experiments were carried out with four miniature pigs. Electromyographic signals from the jaw muscles were recorded simultaneously with jaw movements during natural chewing of foods of differing hardnesses. Harder foods were found to be associated with higher activity levels of jaw-closing muscles and greater lateral deviation, but reduced jaw opening. The sensory supply from one side of the oral cavity was then removed by injected local anesthetic, and the recordings repeated. In addition to decreased activity levels, the jaw-closing muscles showed reduced ability to adjust to different foods. The frequency of mastication fell slightly, and the animals preferred to chew on the uninjected side. Lateral deviation was reduced, but at the same time the jaw-opening muscles usually became more active and accordingly the jaw opened more widely. These findings provide new information on the role of oral sensory afferents in regulating natural chewing patterns. The decreased activities of the jaw-closing muscles are consistent with, although they do not demonstrate, the existence of a positive feedback from periodontal afferents.

Afferent Pathways↗
PubMed1993

[The cohort study on inapparent infection of HFRS in population of Apodemus-type endemic area and in that of Rattus-type endemic area].

Between 1988 and 1990, the positive seroconversion rates of HFRS were tested with a random sample of 7,145 persons in Apodemus-type endemic area and Rattus-type endemic area(type A; type R) in Shandong Province. The results showed that: (1) the highest positive seroconversion rate was in the group of peasants of 20 to 49 years of age in the area of type A; (2) in the area of type R, there was no statistically significant difference in positive seroconversion rates of age, and housewives had the highest rate. The male/female ratio was 2.1-2.2:1 and 0.9:1, respectively in the two types of endemic area. The ratio of apparent infection to inapparent infection was 1:22.6 and 1:42, respectively in the two types of area. It is concluded that inapparent infection is dominant in HFRS infection and there are probably many potential inapparent infections among the population.

Adolescent↗