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Biomedical subjects

M Zhang

Publications and source records attributed to M Zhang.

At least 973 records · Page 54Linked to original sources
PubMed1993

[An experimental observation of effect of tetrandrine on pulmonary dysfunction in rabbit model of smoke inhalation injury].

A rabbit model with severe smoke inhalation injury was adopted to observe the effect of tetrandrine, a calcium antagonist, on pulmonary dysfunction after smoke inhalation during 24 hours post injury. It was found that tetrandrine could decrease the permeability of pulmonary and tracheal vascular permeability (p < 0.01), reduce lung edema and improve the function of respiration. These results imply that tetrandrine might be used in the treatment of inhalation injury.

Alkaloids↗
PubMed1993

[Maxillofacial tomography (MT tomography) in the diagnosis of diseases on the middle 1/3 of the face].

Maxillofacial tomography apparatus (MT tomography) is a panoramic tomographic unit, radiographing in recumbent position. Its image can show most of the anatomic structures of maxillofacial bones. Through comparative examination between the conventional roentgenograms (general radiographs, pantomographs and laminagrams) and MT tomography of 48 patients, it is found that MT tomography has certain advantages for the diagnosis of the range, extent and quality of fracture, tumour and tumour like disease in maxillofacial bones and that MT tomography can serve as an effective auxillary method of diagnosis for the conventional roentgenograms used for maxillofacial bones.

Adolescent↗
PubMed1993

[Study on 125I-labeled human chorinic gonadotropin after purification through gel electrophoresis].

Radioiodination of HCG with 125I Na using chloramine-T is widely employed. However, 125I-HCG damages in storage and thus results in decrease of immunological and biological activities. When 125I-HCG was in store as long as 30 days, the immunological activity and biological activity decreased from 100% to 33.1% and 44.0%, respectively. We used polyacrylamide gel electrophoresis to purify 125I-HCG which had been kept in store for 30 days since radiolabeling, and we found the binding capacities of purified 125I-HCG increased. The combination rates of purified 125I-HCG with antibody and receptors accounted for 90.5% and 95.3% of those of 125I-HCG 1 day after radiolabeling. These results suggest that 125I-HCG which has been stored for a period since radiolabeling should be purified before use.

Chorionic Gonadotropin↗
PubMed1993

[Study on albumin microspheres as drug carrier for liver targeting].

In this paper 6 factors and 12 levels of each variable were selected by Uniform Design Method and computer for preparing albumin microspheres with emulsion-chemical cross-linking. An optimal procedure for preparing albumin microspheres was established and the mean diameter of albumin microspheres is 0.41-0.47 micron. Albumin was labelled with 125I-isotope and 125I-albumin microspheres were prepared according to the optimal procedure. The suspension of 125I-albumin microspheres with 0.1% Tween-80 saline was injected via mice tail vein. The animals were sequentially killed and the radioactivity of blood, spleen, liver, kidney, stomach, heart, lung, thyroid and brain were measured. The results showed that albumin microspheres were accumulated mainly in the liver, about 68% of the injected dose at the peak concentration. The pharmacokinetics of albumin microspheres in liver was also studied and two-compartmental model can be used to describe the regulation.

Animals↗
PubMed1993

[Studies on a radioligand-receptor binding assay of human chorionic gonadotropin in rat testis].

A radioligand-receptor binding assay for human chorionic gonadotropin (HCG) has been established with cell membranes preparation of rat testis. Partially purified cell membranes preparation was prepared from rat testis by sucrose density gradient ultracentrifuge. The binding assay was performed by incubating 125I-HCG with rat testis cell membranes preparation at 30 degrees C for 1.5 h in a total incubation volume of 0.5 ml. Scatchard plot analysis for the binding assay revealed a linear binding plot and yielded a bound capacity of testis cell membranes receptors of 0.36 x 10(-12) mol/micrograms protein. KD of 0.45 x 10(-10) mol/L. Hill coefficient was 0.976. Studies on the kinetics of the reaction of radioligand-receptor binding showed that the mean values for the association rate (k1) and dissociation constants (k2) were individually 0.41 x 10(-3) pmol/min and 2.12 x 10(-3) pmol/min; the dissociation plot was two-phase, with 15 x 10(-3) pmol/min of fast-phase and 1.5 x 10(-3) pmol/min of slow-phase.

Animals↗
PubMed1992

Cloning and intracellular localization of the U2 small nuclear ribonucleoprotein auxiliary factor small subunit.

U2 small nuclear ribonucleoprotein auxiliary factor (U2AF), an essential mammalian splicing factor, is composed of two subunits: a 65-kDa protein (U2AF65), which binds the pre-mRNA polypyrimidine tract and is required for in vitro splicing, and an associated 35-kDa protein (U2AF35). Here we report the isolation of a cDNA encoding U2AF35. U2AF35 contains sequence motifs found in several mammalian pre-mRNA splicing factors. We show directly that U2AF65 and U2AF35 interact with each other and delineate the regions of both proteins that mediate this interaction. Using anti-peptide antibodies against U2AF35, we show that the protein has the intracellular distribution characteristic of U2AF65. Both U2AF65 and U2AF35 are concentrated in a small number of nuclear foci corresponding to coiled bodies, subnuclear organelles first identified by light microscopy in 1903.

Amino Acid Sequence↗
PubMed1992

Mortality and incidence of bladder cancer in benzidine-exposed workers in China.

We examined bladder cancer mortality and incidence to 1981 in 1,972 workers employed in benzidine-exposed jobs in Tianjin, Shanghai, and Jilin, China, between 1972 and 1977, and in 1,974 unexposed workers employed during the same time period. In comparison to general population rates, in the benzidine-exposed group the ratio of observed to expected deaths (SMR) was 17.5 (95% C.I.: 7.5-34.5) and the ratio of observed to expected incident cases (SIR) was 25.0 (95% C.I.: 16.9-35.7). No excess was noted in the unexposed group. The 25-fold increase in bladder cancer incidence in the exposed group was related to level of exposure, with the SIR rising from 4.8 for low exposure to 36.2 for medium exposure, and 158.4 for high exposure. Risks were elevated both for producers of benzidine (SIR = 45.7; 95% C.I.: 20.9-86.8) and for users (SIR = 20.9; 95% C.I.: 12.9-32.0) of benzidine dyes. Benzidine-exposed workers who smoked tobacco had a 31-fold risk (95% C.I.: 20.4-46.4), while non-smoking workers had an 11-fold risk (95% C.I.: 3.6-25.8), suggestive of a multiplicative relationship between these two carcinogens.

Air Pollutants, Occupational↗
PubMed1992

Protection effects of procaine on oxidative stress and toxicities of renal cortical slices from rats caused by cisplatin in vitro.

Incubation of rat renal cortical slices with 2 mM cisplatin (CDDP) at 37 degrees C for different periods of time (15-180 min) increased malondialdehyde (MDA) formation, decreased intracellular glutathione (GSH), and inhibited gluconeogenesis in the slices. CDDP-induced MDA formation increased by 53% after 180 min of incubation and GSH decreased by 35% after 60 min of incubation. Both depletion of GSH and inhibition of gluconeogenesis preceded MDA formation. Procaine (2 mM) completely inhibited CDDP-induced lipid peroxidation without affecting depletion of GSH, but even potentiated gluconeogenesis inhibition, while 2 mM dithiothreitol (DTT) largely reversed all of these biochemical indices. After 240 min of incubation, 2 mM CDDP produced marked cytotoxicities, characterized by an increase in leakage of alkaline phosphatase (ALP) (132%), lactate dehydrogenase (LDH) (115%) and N-acetyl-beta-glucosaminidase (NAG) (157%), decrease in intracellular K+ (64%), and change in total water contents in the slices. Procaine (2 mM) showed protection against CDDP-induced cytotoxicities to a certain extent. These results suggest that depletion of GSH might be a determinant step in the oxidative stress and subsequent cytotoxicity, and that procaine is a powerful antioxidant and would be a promising drug for ameliorating some of the adverse effects of CDDP.

Animals↗
PubMed1992

Differentiation of myoblasts and CNS cells grown either separately or as co-cultures on microcarriers.

Dispersed neuronal and muscular elements from fetal or neonatal origin, can organize and mature in culture when grown on positively charged cylindrical microcarriers (MCS), to a stage which simulate in vivo maturation. Cells arrange themselves on the MCS to form aggregates which remain floating in the nutrient medium. In such a tridimensional organization, the neuronal tissue is capable of regenerating a network of nerve fibers which establish synapse interconnections and undergo myelination. Oligodendrocytes organize on MCS in a tridimensional pattern and produce extensive myelin-like membranes. Myoblasts in MC-cultures fuse into polynucleated myotubes which become striated and contract spontaneously. Creatine kinase and acetylcholine receptor (AChR) are formed during myogenesis in similar quantities in MC-cultures and in monolayers. When both neuronal and muscle tissues are prepared from the same fetus (autologous nerve-muscle co-cultures) and are cultured on MCS, they interconnect to form neuro-muscular junctions. Cells from both tissues, exhibit better differentiation, for longer periods in MC-cultures than they do in monolayers. The floating functional entities are easy to sample and can be harvested for ultrastructural, immunocytochemical and biochemical analysis. In addition, MC-cultures can be used as a good tool for the study of acute and chronic exposures to toxicological agents, as well as for implantation into demyelinated, injured or dystrophic tissues. In this case the MCS in the implanted entities will serve as identifiable markers.

Animals↗
PubMed1992

Simultaneous measurement of left atrial pressure by Doppler echocardiography and catheterization.

Simultaneous, continuous wave Doppler echocardiography, left ventricular systolic and mean pulmonary capillary wedge pressure measurements were performed during cardiac catheterization in 54 patients with mitral regurgitation. Doppler-derived left atrial pressure, which was calculated by subtracting mitral regurgitant gradient from brachial artery systolic pressure, correlated well with mean pulmonary capillary wedge pressure by catheter (r = 0.933, SEE = 2.9 mmHg, P < 0.001); a comparison between non-invasive and invasive systolic gradients across the mitral valve yielded a high correlation (r = 0.91, SEE = 6.0 mmHg, P < 0.001); and there was also a high correlation between brachial artery and left ventricular systolic pressures (r = 0.93, SEE = 4.9 mmHg, P < 0.01). It is concluded that Doppler echocardiography provides a reliable and accurate method for complete non-invasive assessment of left atrial pressure in patients with mitral regurgitation.

Adolescent↗
PubMed1992

Stroke in China (Sino-MONICA-Beijing study) 1984-1986.

We present here the results of the Sino-MONICA-Beijing stroke study based on 700,000 Beijing residents in 1984-1986. To compare incidence rates for stroke with other communities and countries, we adopted the criteria of the WHO Collaborative Study of 17 centers which used the same definition and methodology as was used in this study. Over the 3-year period of the study, 2,593 stroke events were registered in the 25- to 74-year age-group. The incidence rate for all strokes was 189.5/100,000 and the incidence rate for first strokes was 133.6/100,000. Men had a significantly higher incidence rate than women (all strokes 219.7/100,000 for male vs. 160.5/100,000 for female, OR = 1.32, 99% limits 1.19-1.46; first strokes 151.6/100,000 for male vs. 116.4/100,000 for female, OR = 1.25, 99% limits 1.11-1.42). In comparison with other studies, age-adjusted incidence rate of stroke in Beijing was higher than in other countries, especially for hemorrhagic stroke. The proportion of hemorrhagic stroke related to other types of stroke was also higher in Beijing. Further analysis of the cases confirmed by computerized tomography also supported this finding. Unlike the incidence rates, the 4-week case fatality rate for women, 39.5%, was higher than for men, 32.8%. This finding was confirmed by a multiple logistic analysis controlling for age (p less than 0.001) and for previous stroke (p less than 0.001). The adjusted sex difference is also significant (OR = 1.37, p less than 0.001). In addition, results showed that men had a higher hospitalization rate than women. More women than men were treated at home, possibly indicating better medical care for men.

Adult↗
PubMed1992

[The production and identification of partial serogroup--specific monoclonal antibodies against leptospires hebdomadis serogroup].

Hebdomadis is one of the major serogroups found in China. In Sichuan, this serogroup appears to have a close relationship with local outbreak of leptospirosis. BALB/c mice were immunized intrasplenically with outer envelope of serogroup Hendomadis serovar hebdomadis strain 245. Spleen cells were fused with SP2/0 myeloma cells, two monoclonal antibodies Af2 and Bb2 were produced by hybridoma technique. McAb Af2 and McAb Bb2 were identified to be IgG1 and IgG3 by immunodiffusion respectively. Specificities of these two McAbs were determined by MAT; both reacted to 8 serovars (hebdomadis, nona, kambale, kremastos, worsfoldi, jules, maruborincana) of Hebdomadis serogroup. The agglutination titres of McAb Af2 and McAb Bb2 were 1:640-1:2,500,000 and 1:320-1:2,500,000, respectively. The two McAbs did not agglutinate with serovar kabura of Hebdomadis serogroup, they did not agglutinate with 11 serovars of Sejroe serogroup, 4 serovars of Mini serogroup, 18 representive serovars of L. interrogans in 18 serogroups, L. biflexa strain Patoc I and Leptonema illini. So it was found that McAb Af2 and McAb Bb2 showed partial serogroup specificity for Hebdomadis by agglutination.

Animals↗
PubMed1992

Interim report of Sino-Monica-Beijing for the years 1985-1989.

Interim results of Sino-Monica-Beijing for the 5 year period 1985-1989 are reported. The cardiovascular disease (CVD) risk factors increased between the surveys carried out in 1984-1985 and 1988-1989, especially blood cholesterol and body mass index.

Adult↗
PubMed1992

[Doppler echocardiography for measuring the right ventricular diastolic function].

To noninvasively measure the right ventricular diastolic function, continuous wave Doppler echocardiography was used in 31 patients with tricuspid regurgitation (TR). The right ventricular pressure (RVP) curves were analyzed mathematically, showing that RVP declined exponentially after maximum-dP/dt. The instantaneous RVPs during isovolumetric relaxation were measured from RVP curves and also calculated by using exponential equations. There were high correlations between measured and calculated RVPs (r = 0.83-0.98). The tricuspid regurgitant velocities were recorded by CWD and converted into pressure gradients (PG) using a simplified Bornoulli equation. The instantaneous RVPs were then obtained by adding an assumed right atrial pressure to PGs. The maximum-dP/dt, the instantaneous RVP at the time of -dP/dt max (PO) and the time constant of right ventricular relaxation (T) were calculated from both RVP curves and Doppler spectra. The results showed that there were high correlations of -dP/dt max, PO and T measured by two techniques (r = 0.95, 0.98 and 0.92). We conclude that T can be used to quantitate right ventricular myocardial relaxation, and CWD offers a new technique for noninvasively measuring T in patients with TR.

Adolescent↗
PubMed1992

[Clinical pharmacokinetics of cis-diamminedichloroplatinum (DDP)].

We studied the pharmacokinetics of DDP in 9 cancer patients who received iv infusion of DDP (100-120 mg/m2). Platinum concentration was measured by high performance liquid chromatography (HPLC). Plasma clearance of platinum was biphasic. There was a short initial phase with a half life of 19.8 min and a long second phase with a half life of 41.13 hours. A small peak was noted in 5 hours after the end of DDP infusion in about 50% of patients. This suggested tissue reabsorption, release and entero-hepatic circulation. Plasma ultrafiltrable platinum concentration fell with a half life of 21 min. Nearly 75-96% of the platinum in the plasma was protein bound 24 minutes after DDP infusion. The urinary excretion of platinum was found to be 9.52-21.35% in 24 hours with 6.69-19.57% eliminated within the first three hours.

Adult↗