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Biomedical subjects

H Zhao

Publications and source records attributed to H Zhao.

At least 595 records · Page 33Linked to original sources
PubMed1989

[Slide culture and rapid sensitivity test for tubercle bacillus].

We use the slide culture and direct sensitivity test for tubercle bacillus. The sputum specimens was taken from 479 cases. The positive rates of slide culture method and thick smear were 50.5% and 47.8% respectively. The positive rates from slide culture and modified Loewenstein-Jensen medium were 48.2% and 51.9% respectively. The results of sensitivity test of both methods in 40 cases were quite similar. The slide culture technique is a simple, cheap and very rapid method for sensitivity test, it is particularly useful for treatment of pulmonary tuberculosis patients.

Drug Resistance, Microbial↗
PubMed1989

[Clinical and experimental studies of yiqi huoxue principles in treating ulcerative colitis].

Yiqi Huoxue principle (YH) was applied to treat 30 cases of ulcerative colitis while Yiqi Jianpi ( ) and Qingre Qushi ( ) principle (YJQQ), which had been proved its therapeutic effect, was used as the control therapy. The herbal medicines were taken by oral and enema. The course of treatment was 6 weeks. The length, wet and dry weights of thrombus, the platelet adherence and the r, k, Ma, M values of thrombelastogram were measured before and after medications. Before medication, the value mentioned above were all abnormal in both YH and YJQQ group. After medication, with alleviation of the symptoms and signs of the colitis, all these values trend gradually to normal levels (P less than 0.01). The rat models of ulcerative colitis were made by immunological and local stimulation methods. The models were divided into three groups: YH(I), YJQQ(II) and water group(III). Three weeks after medication, the results showed that the lesion degree of the colon, the length and weight both wet and dry thrombus were remarkably lower in group I than those in group III. It was also showed that there was a positive correlation between the lesion degree of colon and the dry weight of thrombus (r = 0.7941, P less than 0.01). It suggested that the therapeutic effects of YH was similar to those of YJQQ in treating ulcerative colitis.

Adult↗
PubMed1989

[Effects of epostane on chorio-trophoblast, co-culture of embryos with endometrium and corpora lutea in vitro].

Effects of epostane on human trophoblast cells, co-culture of mouse embryos with endometrium and guinea pig corpora lutea were studied in vitro. Human chorio-trophoblast cells were obtained from induced abortion (2-2.5 months of pregnancy). The tissue was incubated in control medium or in medium containing epostane. The results indicated that epostane at a concentration of 50 micrograms/ml could injure the human trophoblast cells and its function. Obviously damaged cells were observed at the concentration of 100 micrograms/ml. The cells were degenerated with pyknotic nuclei and sometimes only cell fragments were found. Guinea pig corpora lutea produced progesterone in vitro. In the incubation medium of the control group, the total luteal progesterone increased linearly with the prolongation of incubation during the first 30 min of incubation. The addition of hCG at concentration of 10 IU/ml clearly accelerated progesterone production. Epostane at a concentration of 50 micrograms/ml could significantly inhibit both basic and the hCG-stimulated luteal production of progesterone. Epostane at concentrations of 50 and 100 micrograms/ml showed no inhibitory effect on mouse embryos and endometrium in vitro.

Androstenols↗
PubMed1989

[Peripheral pathway of the blood pressure raised by exciting habenular nuclei].

The electrical stimulation of the habenula (4 V, 100 Hz, 9 s) raised the arterial blood pressure (P less than 0.01) and quickened the heart rate of rats (P less than 0.05). Also, splanchnic nerve discharges were increased (P less than 0.01), the pupils dilated and the ear arteries constricted. The pressor effect was obviously weakened by phentolamine iv (P less than 0.01) and strengthened by bilateral vagotomy (P less than 0.05). The pressor effect disappeared after spinal cord transected at C1. Morphine iv elevated pain threshold (P less than 0.01) and eliminated the pain threshold change caused by exciting habenula. The pressor response of habenula was not influenced by elevating the pain threshold. The results suggest that the pressor effect of habenula occurs via the sympathetic vasoconstrictor fibers, vagus nerve exerts inhibition on the effect and the pressor effect of habenula is not a pain response caused by exciting habenula itself.

Animals↗
PubMed1988

Clinical pharmacokinetics of controlled-release disopyramide in patients with cardiac arrhythmias.

UNLABELLED: The pharmacokinetics of the controlled-release preparation of disopyramide phosphate (Norpace CR, Searle Laboratories, Chicago, IL) were studied in ten patients with cardiac arrhythmias. Multiple-serum disopyramide concentrations were obtained after a 300-mg oral dose. Each patient then received chronic oral therapy with the controlled-release preparation (400 to 1000 mg/day) on an every-12-hour schedule. At steady state, disopyramide trough concentrations were obtained. Serum disopyramide concentrations were determined by high performance liquid chromatography. The regimen was well tolerated by all patients. The mean (+/- SD) time to maximum concentration, maximum concentration, and concentrations 11 and 24 hours after the initial dose were 5.5 +/- 1.3 hours and 2.8 +/- 0.8, 2.0 +/- 0.9, and 1.2 +/- 0.5 micrograms/mL, respectively. A low Cmax to trough concentration ratio of 1.35 +/- 0.26 was observed after the initial dose. Linear regression analysis of the serum disopyramide concentrations 11 hours after initial dose (trough) versus trough concentrations at steady state (dose adjusted) showed a strong correlation (r = 0.87, intercept = 0.03, and slope = 1.9). Regression analysis also showed a strong relationship between the area under the curve (AUC) from time 0 to 11 hours after the initial dose and the trough at steady state (r = 0.86). CONCLUSIONS: The controlled-release preparation of disopyramide, when administered every 12 hours in patients with cardiac arrhythmias, should produce low peaks to trough fluctuations. Because disopyramide concentrations after the initial dose correlate well with trough concentrations at steady state, these concentrations may provide a simple and convenient method for prospective monitoring of disopyramide therapy in patients receiving the controlled-release preparation.

Adult↗
PubMed1988

Effects of sex steroids on regulation of the levels of C1 peptide of rat prostatic steroid-binding protein mRNA evaluated by in-situ hybridization.

Prostatic steroid-binding protein (PBP) is the most abundant protein synthesized in the rat ventral prostate. The protein is under strict androgenic control and is made of two subunits containing the polypeptides C1, C2 and C3. Using an 35S-labelled cDNA probe, we have used quantitative in-situ hybridization to assess the regulation of polypeptide C1 mRNA levels by sex steroids in the adult male rat. Densitometric quantification of autoradiographic hybridization signals revealed that a significant decrease in C1 mRNA levels could be detected 5 h after castration. Levels of C1 mRNA decreased by 50% 2.5 days after castration, while undetectable levels were reached within 7 days. Administration of the potent androgen 5 alpha-dihydrotestosterone to castrated rats caused a progressive increase in C1 mRNA levels which became significant 5 h after the first injection, while prolonged treatment, for 3 and 7 days, caused 50 and 100% reversals respectively of the effect of castration on C1 mRNA levels. Similar results were obtained by dot-blot hybridization using the same 32P-labelled cDNA probe, thus confirming the specificity and quantification achieved by in-situ hybridization. Administration of oestradiol-17 beta to orchiectomized adult rats for 14 days had no effect on steady-state C1 mRNA levels. Progesterone, on the other hand, at the dose used (2 mg twice daily) caused a marked increase in C1 mRNA levels, measured by in-situ hybridization, which was completely reversed by concomitant administration of the pure antiandrogen flutamide. The present data clearly demonstrate that the expression of PBP C1 peptide mRNA is under strict androgenic control and is a very sensitive and specific parameter of androgenic activity. They also indicate that quantitative in-situ hybridization is a powerful, sensitive and most efficient tool to study the regulation of gene expression while, in addition, providing precise information about the site of mRNA localization as well as information about the histology of the tissue, particularly the heterogeneous nature of the acinar response to androgenic stimulation and deprivation.

Androgen-Binding Protein↗
PubMed1987

Distribution of red cell blood group systems in Yi, Tibetan and Manchu ethnic groups in China.

A survey on distribution of ten red cell blood group systems was carried out in 1985 in the Yi, Tibetan and Manchu nationalities in China. Significant differences were found in the distribution of Rh, MNSs, P and especially in the ABO system, while no significant difference was found for Diego, Duffy, Kell, Kidd and XG systems. The DI*a gene frequency was about 0.03, FY*a rather high (0.94), KEL*K extremely low (0.005) and JK*a was about 0.4. In the three nationalities under study, Yi is characterized by high frequencies of the alleles A, M and CDe and by the absence of CDE and Cde. Tibetans show a high frequency of O and a relatively high frequency of P*P1, while Manchus have the lowest frequency of M and in particular of MS.

Alleles↗
PubMed1986

Expression and function of a nonglycosylated major histocompatibility class I antigen.

The major histocompatibility class I antigens, expressed in most somatic cells, have carbohydrate moieties. We constructed mutant mouse MHC class I genes in which codons for the N-linked glycosylation sites were replaced by those of other amino acids. L cell transformants expressing the nonglycosylated class I antigens allowed us to investigate biological roles of carbohydrates with the highest specificity possible. The nonglycosylated antigen was unchanged in its overall serological specificities, and was recognized by alloreactive cytotoxic T cells. Further, the antigen was capable of mediating cytotoxic activity of vesicular stomatitis virus-specific T cells. These studies indicate that carbohydrates are not essential for immunological function of the MHC class I antigens. Cell surface expression of the nonglycosylated antigen was markedly reduced as compared with the native antigen, which was not attributable to accelerated degradation or rapid shedding. We conclude that the primary role of carbohydrates of the class I antigens is to facilitate the intracellular transport of the nascent proteins to the plasma membrane. The possible involvement of carbohydrate-receptor interactions in this process is discussed.

Animals↗
PubMed1985

2.8-A Structure of penicillin-sensitive D-alanyl carboxypeptidase-transpeptidase from Streptomyces R61 and complexes with beta-lactams.

The crystallographic structure of the penicillin-sensitive D-alanyl carboxypeptidase-transpeptidase from Streptomyces R61 has been solved to 2.8-A resolution. The 38,000-dalton serine peptidase has two regions of secondary structure, an alpha/beta cluster, and a region which contains five helical segments. The beta sheet is composed of five beta strands. The tertiary structure has no homology with the classic serine proteases or with the zinc carboxypeptidases. The binding at a common site of three types of beta-lactam (a penicillin, a cephalosporin, a monocyclic beta-lactam) and a desazacyclobutanone has been observed in Fourier difference maps. The binding site sequence is Val-Gly-Ser-Val-Thr-Lys. The beta-lactam ring lies near the enzyme's catalytic serine at position 37, and the C3 substituent of a cephalosporin falls near lysine 40.

Anti-Bacterial Agents↗
PubMed1985

Crystallization and preliminary X-ray data for the exocellular beta-lactamase of Bacillus licheniformis 749/C.

The exocellular beta-lactamase from Bacillus licheniformis 749/C has been crystallized from polyethylene glycol solution at pH 5.5. An X-ray examination of the monoclinic crystals shows the space group is P21, with unit cell dimensions a = 66.77 A, b = 93.77 A, c = 43.57 A and beta = 104.5 degrees. The asymmetric unit consists of two molecules of 28,500 Mr each. The crystals are suitable for structure analysis to at least 2 A resolution.

Bacillus↗
PubMedDate not supplied

Time of symptom onset of eight common medical emergencies.

Specific time periods of the day may be associated with different frequencies of symptom onset in different diseases. The purpose of the current study was to examine times of symptom onset in eight commonly encountered emergent conditions--cerebral infarction, cerebral hemorrhage, transient ischemic attacks, cardiac dysrhythmias, angina pectoris, acute myocardial infarction, gastrointestinal bleeding, and acute asthma. Data from 4554 cases were retrospectively reviewed. Symptom onset frequency curve diagrams were derived, illustrating peak hours of symptom presentation for each of the eight emergent conditions. Hormonal and metabolic factors that may be related to diurnal variations in symptom onset of the eight diseases are briefly discussed.

Acute Disease↗
PubMedDate not supplied

Determination of immunoreactivity of doxorubicin antibody immunoconjugates by a Le(y) competitive RIA.

Many monoclonal antibody-drug immunoconjugates have been evaluated for their ability to deliver cytotoxic drugs to tumors. It is essential to establish that the ability of the conjugates to bind antigen, i.e. their immunoreactivity, is not adversely affected by the drug conjugation procedure. We have described herein a measurement of the immunoreactivity of BR96-DOX, a conjugate comprised of BR96, a chimeric monoclonal antibody specific for the Le(y) tetrasaccharide commonly expressed on human carcinomas, and doxorubicin, an anticancer agent in widespread clinical use. We have employed a competitive RIA, in which microtiter wells were coated with synthetic Le(y) conjugated to human serum albumin and then incubated with 125I-labeled antibody BR96 in the presence of test conjugate or intact BR96 mAb. The test conjugates were found to compete as effectively as unconjugated BR96. This assay is highly applicable to QC processes with the intra-assay CV = 2.0% and the interassay CV = 4.3%.

Antibodies, Monoclonal↗
PubMedDate not supplied

[Expression of the neurotrophin-receptor TrkB predicts outcome in nephroblastomas: results of a pilot-study].

BACKGROUND: The neurotrophin-receptor TrkB plays an important role in pathogenesis, biology and prognosis of neuroblastoma. Expression of TrkB on aggressive neuroblastomas leads to proliferation and survival of the tumor cells and is associated with an unfavorable prognosis. It is now known that Trk receptors are also expressed in extraneural tissues including the kidney. PATIENTS AND METHODS: To study the role of the neurotrophin-receptor TrkB in nephroblastoma/Wilms' Tumor (WT), we determined TrkB mRNA expression by semiquantitative duplex RT-PCR in 39 primary WT. Comparison of mRNA expression levels with clinical variables was performed using Cox regression analysis. RESULTS: The 5-year overall survival was significantly worse for patients with tumors expressing high levels of a functional TrkB-receptor (TrkBfull) in comparison to patients with low levels of TrkBfull (70 % versus 100 %, p=0.005). Conversely, children with tumors expressing high mRNA levels of a functionally inactive truncated TrkB receptor (TrkBtrunc) had a significantly higher 5-year overall survival rate in comparison to patients with low levels of TrkBtrunc (100 % versus 68 %, p=0.003). The hazard ratios for TrkBfull and TrkBtrunc remained significant after adjusting for tumor stage. All WT with high levels of TrkB also expressed the ligand brain-derived neurotrophic factor (BDNF). CONCLUSIONS: Full-length and truncated TrkB appear to be important prognostic factors in WT. Their expression should be assessed prospectively in a larger panel of WT and may have a future role in patient assignment to risk-based treatment strategies. TrkB signaling may be reduced in WT with favorable outcome due to low numbers of TrkB receptors or a competitive effect of functionally inactive TrkBtrunc.

Adolescent↗
PubMedDate not supplied

Profiles of urine samples taken from Ecstasy users at Rave parties: analysis by immunoassays, HPLC, and GC-MS.

The abuse of the designer amphetamines such as 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy) is increasing throughout the world. They have become popular drugs, especially at all-night techno dance parties (Raves), and their detection is becoming an important issue. Presently, there are no MDMA- or MDA-specific immunoassays on the market, and detection of the designer amphetamines is dependent upon the use of commercially available amphetamine assays. The success of this approach has been difficult to assess because of the general unavailability of significant numbers of samples from known drug users. The objectives of the present study are to characterize the drug content of urine samples from admitted Ecstasy users by chromatographic methods and to assess the ability of the available amphetamine/methamphetamine immunoassays to detect methylenedioxyamphetamines. We found that, when analyzed by high-performance liquid chromatography with diode-array detection (HPLC-DAD), 64% of 70 urine samples (by gas chromatography-mass spectrometry [GC-MS]: 88% of 64 urine samples) obtained from Rave attendees contained MDMA and/or 3,4-methylenedioxyamphetamine (MDA) alone or in combination with amphetamine, methamphetamine, or other designer amphetamines such as 3,4-methylenedioxyethylamphetamine (MDEA). This suggests that the majority of the Ravers are multidrug users. At the manufacturer's suggested cutoffs, the Abbott TDx Amphetamine/Methamphetamine II and the new Roche HS Amphetamine/MDMA assays demonstrated greater detection sensitivity for MDMA than the other amphetamine immunoassays tested (Abuscreen OnLine Hitachi AMPS, Abuscreen OnLine Integra AMPS, Abuscreen OnLine Integra AMPSX, CEDIA AMPS, and EMIT II AMPS). There is 100% agreement between each of the two immunoassays with the reference chromatographic methods, HPLC-DAD and GC-MS, for the detection of methylenedioxyamphetamines.

Central Nervous System Stimulants↗