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Biomedical subjects

R Zhang

Publications and source records attributed to R Zhang.

At least 541 records · Page 30Linked to original sources
PubMed1990

[Life span and cercaria shedding of schistosome-infected snails in mountain region of Yunnan].

The life span and cercaria shedding of infected Oncomelania snails in a mountain region of Shitoudi village, Weishan County, Yunnan Province were observed in simulated local ecological environments. 135 infected snails were isolated for observation 3 months after exposure to miracidia in August, 1987. The snail survival rate from the day of initial cercaria shedding to next June, July, August and September was 27.4, 16.3, 13.3 and 11.9% respectively, and the average number of cercariae shed was 139.9, 29.6, 39.2 and 75 per month respectively. The average life span of infected snails was 171.6 days. The average number of cercariae shed per snail in its whole life was 673.0. It was estimated that the average patent period of infected snails was over half a year. As this is the first report in our country in respect to the life span and cercariae shedding of infected snails in a mountain region, the result might be useful for quantitative analysis of epidemiological factors of schistosomiasis in this kind of endemic areas as well as for formulation of control strategy.

Animals↗
PubMed1990

[Objective display on phenomena of propagated sensation along channels (PSC)--changes on the infrared thermal image channels pathway of upper extremity].

This paper reported the observed results on changes of the infrared thermal image of upper extremity induced by needle "Hega" (LI 4), "Daling" (P 7) and "Neiguan" (P6) points. The results indicated that 10 out of 23 cases whose higher and middle temperature bands of upper extremity distributed along the "Dachang" (Large Intestine) channels, when they felt phenomena of propagated sensation along the "Dachang" channels induced by needle "Hegu" points. Those effects did not appear in the objects who did not feel PSC along the "Dachang" channels induced by needled points. Above results provide an objective basis for the phenomena of channels and suggest that the phenomenon of PSC is an objective fact in human body.

Acupuncture Points↗
PubMed1990

[Objective observation on phenomena of sensation along channels (PSC) and QI reaching to affects area (QIRA)--the influence of acupuncture points on infrared thermal image of face].

Thirty three patients and nine volunteers were observed. 18 out of 33 patients felt PSC and Qi reaching to face induced by needle points. The QiRA rate was 80% in patients with face diseases. During acupuncture "Hegu" (LI 4) points, most of the patients felt PSC reaching to their faces and sensed heat in face. The infrared thermal image demonstrated that the temperature of face skin increase and the hyperthermal areas coincided basically with the pathway of "Yangming" channels. Those effects were more than the effects of the other objects who didn't feel PSC or sensed Qi reaching to face induced by needle "Hegu" (LI 4) or "Daling" (P 7) Points. The difference between the two groups was statistical significant. The temperature rising responses induced by needle points were not the results of natural fluctuation. The above results indicate that the PSC and QiRA is objective existence.

Acupuncture Points↗
PubMed1990

[Tentative study of geographical epidemiology of schistosomiasis japonica in Yunnan province].

Schistosomiasis prevails in 17 counties and cities in Yunnan Province. Approximately, a population of 301,511 were affected and the snail-ridden area amounted to 219,000,000m2 in the past years. These endemic areas were not evenly distributed, but rather scattered. The endemic foci were vertically distributed at an altitude of 1,350-2,450 metres above sea level. Human cases were found mostly in areas with an elevation of greater than or equal to 1,800 metres, and became progressively fewer with the ascent. However, in areas with an-elevation of less than or equal to 1800 metres, the infection rate in the inhabitants decreased with the descent. In areas with an average temperature of 11.8-19.5 degrees C and the annual rainfall up to 574-970mm, transmission of the schistosomiasis was always present, suggesting an annual mean temperature around 15.7 degrees C and rainfall 800-900mm were favourable factors for schistosomiasis transmission. The cultivated areas with paddy soils were most suitable for the breeding of Oncomelania snails, where schistosmiasis was severely prevalent. Only a few Oncomelania snails and patients were observed in areas covered with red loam. No patient or snail was found in areas with brown loam or mountain meadow soil.

Animals↗
PubMed1990

[Differential diagnosis of parotid gland masses by gray scale real-time ultrasound].

This paper reports the ultrasonographic diagnoses in 18 cases of parotid gland masses confirmed by surgery and biopsy and pathology. The diagnostic accuracy was 100% (18/18) in the judgement in locations and was 72% (13/18) in the judgement in the nature of the disease. The clinical value of ultrasonographic diagnosis in parotid gland masses and the features of the sonographic images in benign and malignant tumors were analysed and discussed.

Adenocarcinoma, Papillary↗
PubMed1990

[Effect of high carbohydrate and high fat diets on plasma glucose, insulin and lipids in normal and hypertriglyceridemic subjects].

The fasting plasma glucose, insulin and lipids response to high-carbohydrate-low-fat diets and low-carbohydrate-high-fat diets in normal subjects and patients with endogenous hypertriglyceridemia was observed. The normal, high carbohydrate and high fat diets consisted of 60%, 80% and 40% carbohydrate, 25%, 5% and 45% fat and 15% protein of total calorie respectively. The fasting plasma glucose levels increased (P less than 0.01) on day 1, insulin increased on day 3 (P less than 0.01 and P less than 0.05) and TG levels increased on days 3 and 5 after taking high carbohydrate diets both in the normal and hypertriglyceridemic groups. The fasting plasma TC and HDL-C decreased on high carbohydrate diets mainly in the hypertriglyceridemic group. The fasting plasma glucose slightly decreased on day 5, TG decreased on day 1 (P less than 0.05) and TC increased on day 1 and 3 (P less than 0.01) after taking high fat diets, but no differences were observed in insulin levels. Fasting plasma HDL-C levels in the normal group remained unchanged, but significantly decreased 3 days after taking high fat diets in the hypertriglyceridemic group (P less than 0.001). Our results indicate that high carbohydrate intake may be an important cause of hypertriglyceridemia in our country. This diet may cause a slight increase in the blood glucose level, which in turn stimulates an increase in plasma lipids and decrease in HDL-C, which is associated with an increase in the incident of coronary heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[An epidemiological survey of gallstones with gray-scale ultrasound].

Gray-scale real-time ultrasound has been employed to investigate gallstone with a positive result of 553 cases out of 15,856 healthy subjects in city and countryside, the incidence being 34.88%. The feature of incidence is as follows: 1. The incidence of the simple gallbladder stone is more common than that of the other sites (male is about 81.15%, female is about 87.29%); 2. The incidence of gallstones of city residents is higher than that of the country people with significant difference statistically (P less than 0.01); 3. The incidence of gallstone in female city residents is higher than male, about 2.5:1, which shows significant difference. (P less than 0.01); 4. The incidence of gallstones in female city residents is higher than in countryside (P less than 0.01); 5. There is no significant difference in the incidence of gallstone between male and female in the countryside (P greater than 0.05); 6. There is no significant difference in the incidence of gallstones between city male and the male in the countryside (P greater than 0.05); 7. Either in the city or in the countryside, it has been shown that there is a tendency of increasing incidence of gallstone with age in both sexes (P less than 0.01). The relationship between the gallstone and the clinical symptoms has been discussed in this paper.

Adolescent↗
PubMed1990

[Development of passive hemagglutination assay of measles and utilization in serological diagnosis].

The passive hemagglutination assay (PHA) was developed. Preparation of antigen and its stability, sensitivity and specificity was studied. The result showed that the yield of ultrasonic treated antigen is high and its titer has no change in 4 degrees C storage at least 1 month. The sensitized sheep erythrocyte with this antigen have a high specificity and sensitivity. The lysophilized blood cells could stored for a long time in 4 degrees C. A comparison of PHA with hemagglutination inhibition test was carried out by examination of 354 samples of sera from healthy children. The GMT of titer of antibodies of measles were 26.20 and 13.92 respectively. The result showed that the two methods were highly related.

Antigens, Viral↗
PubMed1989

Heterogeneity of rat ovarian lactogen receptor species.

Three distinct ovarian lactogen receptor species with unique and highly reproducible HPLC retention times gave corresponding peaks of binding activity and migrated as single bands of 80, 40, and 34 kDa on SDS-PAGE. Reduction of the 80 kDa protein failed to reveal any conversion to the lower molecular weight proteins by either SDS-PAGE analysis or reverse phase HPLC, suggesting that the three binding proteins are not related by disulfide bond formation. Immunological studies indicate an amino acid homology at a C terminal region among the 3 receptor forms and with the rat liver receptor. However, the 80 kDa ovarian receptor also contains a unique sequence derived from microsequencing that is not immunologically apparent in the ovarian lower molecular weight forms of the rat liver receptor. These findings substantiate the existence of at least two populations of ovarian lactogen receptors perhaps originating within the same gene, a high Mr form potentially capable of signal transduction, and truncated forms that could be involved in transport and/or clearance.

Animals↗
PubMed1989

Rare clonal karyotypic variants in primary cultures of human breast carcinoma cells.

Cytogenetic analyses were performed on 40 previously untreated primary human breast carcinomas, four untreated breast metastases, nine human breast fibroadenomas, and ten normal human mammary tissues, all in primary culture. The results revealed predominantly normal diploid cells with abnormal clones in two of 40 primary carcinomas and one of four metastases. 3p deletion [del(3)(p14-21)], similar to that associated with small cell lung cancer, was found in a primary tumor from a patient with bilateral breast cancer. In addition, a clone with t(1;4) was found in another primary breast carcinoma, while a t(1;5) clone was found in a metastatic tumor.

Breast↗
PubMed1989

Characterization and structure of ovarian and testicular LH/hCG receptors.

Ovarian and Leydig cell LH/hCG receptors purified to homogeneity were identified as a single protein of Mr 80,000 and 90,000 respectively. The homogeneity of this protein was confirmed by microsequencing of the first 18 amino acids of the ovarian receptor. The unblocked N-terminal peptide consisted of NH2-R-E-L-S-G-S-R-X-P-E-P-X-D-X-A-P-D-G. These receptors are N-linked sialoglycoproteins which accounts for the size difference between testicular and ovarian receptors and may participate in the interaction with gonadotropin. Crosslinking of pure receptor with hCG with 125I label in either subunit indicated significant interaction of alpha-hCG with the receptor, while beta-hCG seems involved mostly through association and conformational influence on the alpha-subunit. Comparison of Mr derived from SDS with those from FPLC suggested that the native LH receptor are dimers of identical subunits. Autoradiographs of blotted receptors demonstrated that both monomeric and dimeric forms can bind hCG. Receptors from both tissues can be phosphorylated by the catalytic subunit of cAMP-dependent protein kinase and phosphopeptide maps were identical. Receptor occupancy by agonist leads to a conformational change which facilitates its phosphorylation during initial binding and reduces the rate of phosphorylation after more prolonged exposure to gonadotropin. Aggregation or dimerization of the hCG/LH receptors could promote clustering and or crosslinking of receptors in the membrane favouring the initial transduction steps in the action of these hormones.

Amino Acid Sequence↗
PubMed1989

Sorption and metabolism of metolachlor by a bacterial community.

A stable bacterial community absorbed and transformed the herbicide metolachlor [2-chloro-N-(2-ethyl- 6-methylphenyl)-N-(2-methoxy-1-methylethyl)-acetamide] from a liquid medium. About 80% of the added ring-[U-C]metolachlor (50 mug/ml) disappeared from the medium and accumulated inside the cells. The ratio of cellular C to C in 1 mg of supernatant reached a value of 1.1 x 10 in a 10-day-old culture. C remaining in the medium consisted primarily of two dechlorinated products of metolachlor with m/z 233 and 263 as determined by mass spectrometry. The C-labeled material absorbed by the cells was strongly bound; only 2% of the C was released into deionized water after shaking for 3 h. Approximately 96% of the C associated with the biomass was extracted with acetone, and high-performance liquid chromatographic analysis of this fraction showed six peaks containing radioactivity. Since no metolachlor was detected by chromatographic analysis, it was concluded that the radioactivity recovered from the cells represented transformed products of metolachlor. Pure cultures isolated from the bacterial mixed culture were less effective in transforming and accumulating metolachlor. These results suggest that it may be advantageous to seed an aquatic environment with a mixture of microorganisms, rather than individual microbial species, as a method for removal or detoxification of metolachlor.

Journal Article↗
PubMed1988

Kinetics of disulfide exchange reactions of monomer and dimer loops of cysteine-valine-cysteine peptides.

Rate constants have been determined in 3 M guanidine hydrochloride for disulfide exchange reactions between glutathione and two synthetic peptides containing a cysteine-valine-cysteine region. Equilibrium experiments demonstrate the absence of noncovalent peptide aggregation in this solvent. Procedures are given for separating seven different components in quenched reactions, including the fully reduced cysteine cluster, the monomeric disulfide loop, parallel and antiparallel dimer loops, and the three monomers containing one or two mixed disulfides with glutathione. Intramolecular rate constants for (1) formation of a sterically strained monomer loop, (2) transfer of glutathione between the two cysteines on the same peptide chain, and (3) formation of unstrained dimer loops correspond to a series of processes forming rings of increasing size. In one sequence, these rate constants are 3, 6, and about 21 s-1, respectively. The larger loops are formed more easily. In the other sequence, rate constants for formation and opening of monomer loops are accelerated 180- and 1300-fold, respectively, relative to analogous reactions in a peptide containing eight residues between the two cysteines. This gives a 7-fold smaller equilibrium constant for ring closure in the cysteine cluster. Dimer formation occurs by a mechanism utilizing the accelerated opening of monomer loops. Results provide information assisting efforts to develop strategies for directing disulfide pairing in novel protein structures. Results also help define factors contributing to formation of undesired oligomers during efforts to refold cysteine-containing proteins obtained by bacterial expression of mammalian genes.

Chromatography, High Pressure Liquid↗
PubMed1988

Cytokinin Biochemistry in Relation to Leaf Senescence: IV. Cytokinin Metabolism in Soybean Explants.

When [(3)H]dihydrozeatin riboside and [(3)H]zeatin riboside were supplied to soybean (Glycine max L.) explants (comprising one leaf, associated pods, and subtending stem) via the xylem at mid to late podfill, 0.1% of the supplied (3)H was extracted from the seeds. The distribution of (3)H in the explants was similar to that bound previously following uptake of [(3)H]zeatin riboside at earlier stages of pod development. Metabolites formed in the explants from (3)H-labeled zeatin, zeatin riboside, and dihydrozeatin riboside were identified and related to the endogenous cytokinins shown to be present. When zeatin riboside and zeatin were supplied for 1 hour, zeatin nucleotide was the principal metabolite formed and this appeared to be the precursor of the other metabolites detected subsequently. Explants supplied with zeatin riboside or dihydrozeatin riboside for 1 hour, and then transferred to water for 20 to 24 hours, yielded leaf blades in which the main metabolites were O-glucosyldihydrozeatin, adenosine, and adenine. The metabolism of zeatin riboside in blades of explants at pre-podfill, early podfill, and mid to late podfill did not differ appreciably. The results are discussed in relation to leaf senescence and seed development.

Journal Article↗
PubMed1988

A new macromolecular antitumor antibiotic, C-1027. I. Discovery, taxonomy of producing organism, fermentation and biological activity.

Strain C-1027, an actinomycete isolated from a soil sample collected in China, was found to produce the new antibiotic, C-1027. From taxonomical studies on its morphological, cultural and physiological characteristics, this antibiotic-producing strain was identified as Streptomyces globisporus C-1027. Antibiotic C-1027 has antimicrobial activity against most Gram-positive bacteria but not against Mycobacterium sp. or Gram-negative bacteria. This antibiotic shows remarkable activity in spermatogonial assay and potent cytotoxicity against KB carcinoma cells in vitro, and exhibits inhibition on transplantable tumors in mice.

Aminoglycosides↗
PubMed1988

A new macromolecular antitumor antibiotic, C-1027. II. Isolation and physico-chemical properties.

A new macromolecular antibiotic C-1027 was obtained from the broth filtrate of Streptomyces globisporus C-1027 by precipitation with ammonium sulfate, DEAE-cellulose column chromatography and gel filtration chromatography on a Sephadex G-75 column. This antibiotic, prepared as a white powder, is an acidic polypeptide having an isoelectric point of pH 3.5-3.7 and a molecular weight of 15,000 as determined by SDS-polyacrylamide gel electrophoresis and gel filtration chromatography. The acid hydrolysate of the purified antibiotic C-1027 contained no methionine or tryptophan. From the physico-chemical data, it may be considered to possess a very labile non-protein chromophore.

Amino Acids↗