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Biomedical subjects

G Zhang

Publications and source records attributed to G Zhang.

At least 559 records · Page 31Linked to original sources
PubMed1995

v-rel Induces ectopic expression of an adhesion molecule, DM-GRASP, during B-lymphoma development.

In an effort to identify aberrantly expressed genes in v-rel-induced tumors, monoclonal antibodies were developed that reacted selectively with avian B-cell tumors. One antibody, HY78, immunoprecipitated a 120-kDa glycoprotein (p120) from cells that express v-rel. N-terminal amino acid sequencing of p120 identified a 27-amino-acid sequence that is also present in DM-GRASP, an adhesion molecule belonging to the immunoglobulin superfamily. Evidence from tissue distribution, immunological cross-reaction, PCR amplification, cDNA cloning, and DNA sequence shows that p120 is indeed DM-GRASP. Northern (RNA) analysis using a probe from the DM-GRASP gene identified a 5.3-kb transcript in mRNA from bursa, thymus, and brain as well as from v-rel-induced B-cell lymphomas but not from bursal B cells. The induction of this protein by v-rel during the development of bursal B-cell lymphomas appears, therefore, to be ectopic in nature. Overexpression of v-rel or c-rel in chicken embryonic fibroblasts, B-cell lines, and spleen mononuclear cells induces the expression of DM-GRASP. The ratio of DM-GRASP to v-Rel was fivefold higher than that of DM-GRASP/c-Rel in a B-cell line, DT95. Interestingly, the presence of HY78 antibody inhibits the in vitro proliferation of v-rel-transformed cells but not cells that immortalized by myc. These data suggest that DM-GRASP is one of the genes induced during v-rel-mediated tumor development and that DM-GRASP may be involved in the growth of v-rel tumor cells.

Activated-Leukocyte Cell Adhesion Molecule↗
PubMed1995

FGF-1 in normal and regenerating kidney: expression in mononuclear, interstitial, and regenerating epithelial cells.

The proximal tubule epithelium regenerates following nephrotoxic damage. To determine the role of fibroblast growth factors (FGFs) in the regeneration of rat proximal tubule epithelial (RPTE) cells, we investigated proliferation, differentiation, and FGF-1 expression in vivo in rat kidney before and after nephrotoxic damage to the proximal tubule epithelium caused by S-(1,1,2,2-tetrafluoroethyl)-L-cysteine administration. In undamaged kidneys, FGF-1 was expressed in distal tubule elements, including cortical and medullary collecting ducts, as well as in blood vessels and glomeruli, but was absent in RPTE. One day after damage, there was an increase in proliferation of surviving proximal tubule epithelial cells and a coincident increase in FGF-1 expression in invading mononuclear cells. After this initial burst of proliferation, FGF-1 expression increased in poorly differentiated vimentin-positive regenerative epithelial cells, indicating that autocrine FGF-1 expression in the regenerative epithelium is a later event in the regeneration process. FGF-1 staining persisted in foci of macrophages, interstitial cells, and nephropathic tubules within areas of interstitial expansion 2 wk after damage. We concluded that transient paracrine and autocrine expression of FGF-1 could play mitogenic and/or morphogenic roles during tubular regeneration. Persistent expression in macrophages, fibroblasts, and nephropathic tubules may be associated with tubular degeneration. FGF-1 expression may be an important contributor to both tubular regeneration and degenerative disease following toxicant exposure.

Animals↗
PubMed1995

CT analysis of postoperative changes after thalamotomy for Parkinson's disease.

Stereotactic operations have long been used to relieve agitation and muscle rigidity in Parkinson disease. Because of its high-density resolution, CT is quite effective to portray the location, size, shape and density of the thermocoagulative focus. The foci were classified into different types according to their changes in different time periods. Correlation with pathological changes was discussed.

Adult↗
PubMed1995

Mutation T318M in the CYP11B2 gene encoding P450c11AS (aldosterone synthase) causes corticosterone methyl oxidase II deficiency.

Corticosterone methyl oxidase (CMO) deficiency refers to disorders of aldosterone synthesis due to mutations in the CYP11B2 gene encoding cytochrome P450c11AS, which is the adrenal aldosterone synthase. Type I CMO deficiency is associated with low concentrations of 18OH-corticosterone and aldosterone, due to severe mutations in P450c11AS; while type II CMO deficiency is associated with high concentrations of 18OH-corticosterone and low concentrations of aldosterone, due to less severe mutations of P450c11AS. A single type of mutation, compound homozygosity for R181W and V386A, has been reported as the cause of CMOII deficiency in an inbred population. We now report a patient with a typical clinical and hormonal picture of CMOII deficiency. Direct sequencing of patient and parent DNAs showed that the mother's allele contributed R181W and the deletion/frameshift mutation delta C372, while the father's allele contributed T318M and V386A. These mutants were recreated in cDNA expression vectors singly and in the parental pairs, showing that neither allele contributed any measurable activity. This would suggest the patient should have CMOI deficiency. These studies suggest that other factors besides P450c11AS are involved in the genesis of the distinctive CMOI and CMOII phenotypes.

Base Sequence↗
PubMed1995

[An approach to determining the effect on salivary amylase by green tea extract].

The inhibition effect of three Chinese tea and a kind of acid tea without fluoride to human salivary amylase were studied. The inhibited ability of polyphenols and fluoride were further studied, simultaneously, the tea: saliva ratio were also tested in vitro. The results indicated that the inhibition effect was in this order: acid tea, Ulong tea, longjing, huacha. The polyphenols play important role in the inhibition of salivary amylase, the optimal ratio between tea and saliva was 0.6:1.

Amylases↗
PubMed1995

Platelet-derived growth factor in experimental glomerulonephritis.

Growth factors and in particular platelet-derived growth factor (PDGF) have been implicated in the pathogenesis of glomerulonephritis and glomerulosclerosis. We have studied the distribution of immunoreactive PDGF (iPDGF) within serial kidney biopsies (days 7, 15, 30, 90 and 120) of eight rats with an accelerated form of nephrotoxic serum nephritis (NTN). The course of NTN was mild in five rats and seere in three. Two patterns of immunostain for PDGF were noted. The first consisted of iPDGF-B chain in a glomerular segmental distribution similar to that of infiltrating monocytes (OX6+cells). At all stages of NTN the distribution of iPDGF-B chain correlated closely with the immunostain for monocytes. The second pattern of immunostain showed iPDGF-A chain in a diffuse distribution along the glomerular capillary lining and to a lesser extent in some mesangial cells. In severely affected rats the magnitude of the iPDGF-A increased along with glomerulosclerosis but disappeared later from areas of segmental and global glomerular obsolescence. By contrast, in rats with milder NTN glomerular iPDGF-A chain peaked early and decreased subsequently.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[Ecological studies on the growth of Pinellia ternata (Thunb.) Breit].

The results show that the following ecological requirements must be met for Pinellia ternata to grow well: warm climate (appropriately 10-27 degrees C), adequate humidity and scattering sunlight. Burning sunlight and high temperature, as well as waterlogging are harmful to its growth.

Humidity↗
PubMed1995

[A preliminary study on bioactivity of orange and tangerine peel extracts against aphis and mites].

An assay was made on the bioactivity of the extracts of tangerine peel from Cinocitrus tangerina, orange peel from Citrus sinensis and mixed tangerine peel from Cinocitrus sp. against aphis Semia phis heraclei, Aphis craccivora, Uroleucon gobonis and Myzus persicae using residual film or topical method, and against mites Tetranychus viennensis and T. trancatus using slide-dip or immersion method. Test results show that these extracts have strong bioactivity against aphids and mites. The corrected mortality regression equations and LC50 (or LD50) of these extracts to pests are presented.

Animals↗
PubMed1995

Changes of endothelin during cerebral vasospasm after experimental subarachnoid hemorrhage.

Laser-Doppler flowmetry was employed in the observation of regional cortical blood flow (rCBF) after experimental subarachnoid hemorrhage (SAH) in anesthetized rats and the contents of endothelin (ET) in the cerebral-spinal fluid (CSF), plasma, hypothalamus, cerebral cortex, cerebellum and medulla were simultaneously measured. There was a biphasic change of rCBF after SAH. The contents of ET in CSF, plasma and hypothalamus rose prominently in the early stage after SAH, and the ET-increase in CSF and hypothalamus was earlier than that in plasma. The changes of ET contents in CSF correlated well with that in hypothalamus. Our results suggest that ET probably is an early important factor which induces cerebral vasospasm (CVS) after SAH. The increase of ET in CSF, which may originate from the hypothalamus, might play a more important role in the development of CVS after SAH than that in plasma.

Animals↗
PubMed1995

[Cloning of anti-breast cancer monoclonal antibodies from phage antibody libraries].

Rodent monoclonal antibodies (McAbs) with anti-tumor specificity can be isolated from hybridomas by screening reactivity against tumor cells. Here, as an approach to bypass hybridoma technology, we attempted to isolate anti-tumor rodent McAbs directly from phage antibody libraries. We first used RT-PCR reactions to amplify diverse repertoires of heavy (Fd part) and light chains from spleen lymphocytes of Balb/c mice immunized with human cancer cell line BCap37 and then, by recombination of the repertoires in bacteria, generated a repertoire (1.0 x 10(7)) of Fab fragments displayed on filamentous phage. Four rounds of selection against living cancer cells showed specific enrichment of phage antibodies. After the fourth round of selection 174 out of 182 clones exhibited cancer cell binding capacity. The specificity of those clones was verified by reactivity against 12 human tumor cell lines, human lymphocytes and fibroblasts. In the production of monoclonal antibodies toward human cancer, this strategy may provide an alternative approach, and even surpass the hybridoma technology.

Animals↗
PubMed1995

[Repair of soft tissue defect on the hand using antebrachial posterior interosseous artery retrograde island flap].

Eight cases of hand defects have been repaired with the antebrachial posterior interosseous artery retrograde island flap. The vessel of the flap is constant and rich in cutaneous branches. The flap has good blood supply, larger surface, appropriate thickness and good skin texture with well-matched color. The operation is simple with high rate of success and does not need to sacrifice a major artery in the forearm.

Adult↗
PubMed1995

[Effects of manganese on learning abilities in school children].

Manganese in drinking water of Wu Village, Qingchu County, Taiyuan, Shanxi Province persisted in an excessive level all the year round, hair and blood manganese contents in its primary school pupils, averaged 1.242 micrograms/g and 617 nmol/L (3.39 micrograms/dl), respectively, were higher than those in normal children, and the school records of the former were poorer than those of the latter. Levels of serum 5-hydroxytryptamine (5-HT), dopamine, norepinephrine and acetylcholine esterase of those 92 school children were determined to study their relationship with poor learning abilities. Results showed levels of four neurotransmitter in them all were lower than those in control children. School records for Chinese language and mathematics correlated positively to the levels of most neurotransmitter. Multiple linear regression analysis showed the order of the effects of neurotransmitter on school records of Chinese language was 5-HT, norepinephrine, acetylcholine esterase and dopamine, and those on mathematics was norepinephrine, 5-HT, acetylcholine esterase and dopamine.

Adolescent↗
PubMed1995

[Urinary calcium excretion in patients with pregnant hypertension syndrome].

We observed the urinary calcium in 103 patients in the third trimester of pregnancy and the relation between the 24 hour calcium excretion and the calcium/creatinine ratio of a single void urine sample. The study population included 75 normal pregnant women and 28 pregnant woman with pregnant hypertension syndrome. The 24 hour urinary calcium excretion in the patients with pregnant hypertension syndrome was significantly lower (0.70 +/- 0.36 mmol/L) than that in normal pregnant women (4.00 +/- 1.90 mml/L) P < 0.0005. The 24 hour calcium excretion correlated well with the calcium to creatinine ratio of a single void morning urine sample in the two groups. We conclude that the urinary calcium excretion can be used as an indicator for pregnant hypertension syndrome. The 24 hour urinary calcium excretion can be estimated from a single void urine sample. Pregnant hypertension syndrome is associated with hypocalciuria, probably due to increased tubular reabsorption of calcium.

Adult↗
PubMed1995

[Pharmacological studies of Polygonum capitatum Buch-Ham. ex D. Don].

The pharmacological effect of aqueous extract of Polygonum capitatum has been studied. The experimental results show that Polygonum capitatum markedly decreases WBC and RBC in urine of pyelonephritis mode in rats, the death rate of Escherichia coli infected mice, and the temperature of feverish rabbits. It has also been found that after oral administration of Polygonum capitatum the animal urine markedly inhibits the growth of Escherichia coli, but diuretic action of the herb has not been observed.

Animals↗
PubMed1995

Identification and classification of Neisseria gonorrhoeae by RAPD fingerprinting.

Using the RAPD method, we identified and classified Neisseria gonorrhoeae on the basis of the DNA level. Except OPG20 the other 19 primers of OPG arbitrary primer kit showed informative arrays of amplified prominent segments. Most of the segments were common to all three Neisseria gonorrhoeae groups; some segments were amplified from two groups or only one group so that the fingerprint maps of different Neisseria gonorrhoeae groups were distinctive. Based on these findings, i.e. on the genomic level, we can classify the three Neisseria gonorrhoeae groups. Using OPG10 and OPG11 to amplify the five Neisseria species, we found marked diversity among them, which made it easy for us to identify Neisseria gonorrhoeae from four other Neisseria species. The use of the RAPD method needs some special reaction conditions, e.g. annealing temperature that should not be too low or too high and should be consistently stable. The quality of Taq polymerase is also very important. The reproducibility of the results under these conditions was very good.

Base Sequence↗
PubMed1995

[The effect of sagittal split ramus osteotomy advancement and setback mandible on occlusal force and masticatory efficiency].

21 patients (mandibular prognathism = 11, mandibular retrognathism = 10) whose occlusal force and masticatory efficiency were measured and analysed preoperatively, three and six months following sagittal split ramus osteotomy. The result shows that, in individuals with mandibular retrognathism treated by lengthening of the mandible, the occlusal force and masticatory efficiency would decrease, in individuals with mandibular prognathism treated by reduction in mandibular length, the occlusal force and masticatory efficiency would increase. There is no linear correlation relationship between the change of the occlusal force and the movement of the angle and the distance of the mandible.

Adult↗
PubMed1995

Nonpeptide glycoprotein IIb/IIIa inhibitors. 5. Antithrombotic effects of MK-0383.

The antiaggregatory and antithrombotic actions of MK-0383, a low molecular weight, nonpeptide antagonist of the platelet glycoprotein IIb/IIIa, were evaluated in a variety of canine models. Inhibition of ex vivo platelet aggregation responses to ADP and collagen were observed after the acute sequential i.v. administrations of 10 to 500 micrograms/kg or 360-min continuous i.v. infusions of 1 to 10 micrograms/kg/min of MK-0383. Hemostatic function normalized within 30 (platelet response to collagen, template bleeding times) to 90 min (platelet response and sensitivity to ADP) after the termination of 360-min i.v. MK-0383 infusions, suggesting no protracted, direct effects on platelet function. With acute sequential i.v. administrations of MK-0383, platelet response to ADP was abolished without significant extension of bleeding time. In a model of platelet-dependent cyclic flow reductions in injured, stenosed left circumflex coronary artery, the bolus i.v. administrations of 300 and 1000 micrograms/kg of MK-0383 totally abolished cyclic flow reductions for periods of 18 +/- 1 and 37 +/- 5 min, respectively. In a model of electrically induced left circumflex coronary artery occlusive thrombosis, 10 micrograms/kg/min i.v. of MK-0383 initiated 15 min before electrical injury prevented occlusive thrombosis in three of six preparations despite continued electrical stimulation of the vessel for 300 min, delayed occlusion in three of six preparations (160.3 +/- 5.5 min) and reduced thrombus mass (5.1 +/- 1.3 mg), compared to the development of occlusive thrombosis in six of six saline-treated preparations (50.5 +/- 8.7 min; 19.1 +/- 3.0 mg). When administered as an adjunct to thrombolytic agents in the presence of background heparin for lysis of electrically induced left circumflex coronary artery occlusive thrombus, 10 micrograms/kg/min i.v. of MK-0383 initiated 15 min before tissue-type plasminogen activator or streptokinase increased the incidence of (tissue-type plasminogen activator: eight of nine MK-0383 vs. three of eight saline; streptokinase: eight of eight MK-0383 vs. two of eight saline) and accelerated reperfusion, and reduced the incidence of acute thrombotic reocclusion during continued MK-0383 infusion. These findings indicate significant antithrombotic potential for MK-0383 alone or as an adjunct to thrombolytic therapy in the treatment of coronary artery ischemic syndromes.

Adenosine Diphosphate↗