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Biomedical subjects

B Zeng

Publications and source records attributed to B Zeng.

30 records · Page 2Linked to original sources
PubMed1996

Closed anesthesia with nitrous oxide.

Anesthesia was induced with intravenous thiopental, fentanyl, and succinylcholine, and maintained with isoflurane, N2O-O2 and atracurium after denitrogenation in 20 adult patients. Inspired and end-tidal concentrations of O2, N2O, CO2, isoflurane and oxygen saturation of pulse oximeter (SpO2) were monitored. After intubation, N2O (750 ml/min) and O2 (250 ml/min) were administrated. When inspired N2O concentration (FiN2O) reached 60% the closed anesthesia was initiated by adjusting fresh gas flow rate in order to meet the oxygen demand of the patients. The N2O/O2 ratio was constantly kept at 0.7. The results revealed that during wash-in period, FiN2O increased, on average, to 30% at 3.83 min, 40% at 6.22 min, 50% at 14.13 min respectively. After 30 min of closed anesthesia, FiN2O decreased to 49.4%. It was 46.8% at 60 min. Thereafter it increased smoothly to 51.9% at 180 min. No hypoxia and hypercapnia occurred. Compared with commonly used high flow N2O-N2 inhalation, the technique of low flow wash-in and closed circuit maintenance with N2O-O2 may be less expensive and feasible and causes less pollution.

Abdomen↗
PubMed1996

[Expression of myelin basic protein gene in the developing human brain].

The expression of myelin basic protein (MBP) gene in the developing human brain was studied by using Northern dot blot and in situ hybridization with 32P- and biotin-labeled rat MBP cDNA and Diglabeled human MBP cRNA probes so as to explore the relation of temporal and spatial expression of human MBP gene to myelinogenesis and myelination. The results of dot blot analysis showed that the expression of MBP mRNA was near 2.0 A590/microgram of RNA in the fetal brain at 16 weeks of conceptional age, and it increased progressively with development to have 9-fold increment (18 A590/microgram of RNA) in the adult brain. The insitu hybridization was performed with the sections of fetal spinal cord and medulla oblongata at 8-25 weeks of conceptional age, and of pons, midbrain, thalamus, cerebellum and cerebrum at 20, 22 and 25 weeks. The results indicated that the expression of MBP mRNA was found as early as 8-9 weeks and localized within the perinuclear cytoplasm of the scattered cells in the ventral horn of spinal cord and near the basis of the fourth ventricle of medulla oblongata. Whether the above-mentioned labeled cells are neurons or precursors of glial cell remains to be identified because they are larger in size and have more abundant cytoplasm than oligodendrocytes. The labeling of MBP mRNA abruptly increased and spread with the processes of oligodendrocytes to form a network in spinal cord and medulla at 20 weeks; meanwhile, labeling was obvious in pons and scattering in the other brain regions examined.

Adult↗
PubMed1994

Sequencing of chromosome I of Saccharomyces cerevisiae: analysis of the 42 kbp SPO7-CENI-CDC15 region.

Determination of the DNA sequence and preliminary functional analysis of a 42 kbp centromeric section of chromosome I have been completed. The section spans the SPO7-CEN1-CDC15 loci and contains 19 open reading frames (ORFs). They include an apparently inactive Ty1 retrotransposon and eight new ORFs with no known homologs or function. The remaining ten genes have been previously characterized since this part of the yeast genome has been studied in an unusually intensive manner. Our directed sequencing allows a complete ordering of the region.

Chromosome Mapping↗
PubMed1993

Physical localization of yeast CYS3, a gene whose product resembles the rat gamma-cystathionase and Escherichia coli cystathionine gamma-synthase enzymes.

We have cloned, sequenced and physically mapped the CYS3 gene of Saccharomyces cerevisiae. This gene can complement the cys3-1 allele, and disruptions at this locus lead to cysteine auxotrophy. The predicted CYS3 product is closely related (46% identical) to the rat cystathionine gamma-lyase (Erickson et al., 1990), but differs in lacking cysteine residues. These results provide further evidence that the S288C strain of yeast resembles mammals in synthesizing cysteine solely via a trans-sulfuration pathway. The CYS3 product was found to have strong homology to three other enzymes involved in cysteine metabolism: the Escherichia coli metB and metC products and the S. cerevisiae MET25 gene product. The trans-sulfuration enzymes appear to form a diverged family and carry out related functions from bacteria to mammals.

Amino Acid Sequence↗
PubMed1993

Sequencing of chromosome I from Saccharomyces cerevisiae: analysis of a 32 kb region between the LTE1 and SPO7 genes.

The DNA sequencing and preliminary functional analysis of a 32 kb section of yeast chromosome I has been completed. This region lies on the left arm of the chromosome between the LTE1 and SPO7 genes and contains 14 open reading frames (ORFs) positioned closely together, with an average spacing of approximately 350 nucleotides between coding regions. Three of these ORFs correspond to previously identified genes, a further three show significant homology with other proteins, while the remaining eight ORFs share no significant homology to genes in the databases.

Amino Acid Sequence↗
PubMed1992

[Tumor necrosis factor alpha activity in peripheral blood in patients with acute leukemia: changes and clinical implications].

The production of tumor necrosis factor alpha (TNF alpha) of peripheral blood mononuclear cells was investigated in 58 patients with acute leukemia. The results showed that the production of TNF alpha was significantly lower in 41 of the 58 patients than that of normal controls. The TNF alpha activity levels from patients with acute monocytic leukemia and acute myelomonocytic leukemia were higher than those from patients with acute lymphoblastic leukemia and acute granulocytic leukemia (P < 0.05). The TNF alpha activity level changed in various courses of the disease and returned to normal during the period of complete remission. It was noted that patients with higher or normal TNF alpha levels had a higher complete remission rate than those with lower TNF alpha level (P < 0.01). These results indicated that determination of TNF alpha maybe helpful in observing changes of the disease and predicting prognosis.

Adolescent↗
PubMed1991

[Change of T lymphocyte subsets in peripherial blood of children with malnutrition and zinc deficiency].

Sixty children with malnutrition were investigated in this study. The results showed a reduction of serum zinc in moderate and severe cases compared with the mild and normal groups. OKT3+, OKT4+ and OKT8+ cells in peripheral blood of mild malnutrition were significantly decreased in contrast to normal control. The reductive degree of OKT8+ and OKT4+ cells correlated with the severity of malnutrition. OKT8+, OKT4+ and OKT4+/OKT8+ ratio of moderate and severe malnutrition with infection were much lower than those without infection. Our findings suggested that main effective and regulative cells of cell-mediated immunity were impaired. OKT3+ and OKT4+ cells might be used as a sensitive index for early assessment of the immune function in malnutrition children.

CD4-CD8 Ratio↗
PubMed1991

[Effect of tetrandrine and verapamil on left ventricular diastolic and systolic function in essential hypertension].

By using apexcardiography and echocardiography, the diastolic and systolic function of 34 hypertensive patients were studied. The results indicated that left ventricular (LV) hypertrophy is one of the important factors in impairing LV diastolic function in essential hypertension. By using self-control method, Verapamil(V) was injected intravenously. Relative A wave to total diastolic amplitude (A/D), total apexcardiographic relaxation time index (TARTI), diastolic amplitude time index (DATI) and PEP/LVET were measured. After 5 half-lives of V, intravenous Tetrandrine (T) was given, all the measurements were repeated in the same way. The data revealed that A/D, TRATI and DATI improved significantly after intravenous T and V as well, yet PEP/LVET showed no significant change. It, therefore, seems clear that both T and V could induce a significant improvement in LV diastolic function without any apparent adverse influence on systolic function.

Adult↗
PubMed1990

Intravenous tetrandrine in terminating acute episodes of paroxysmal supraventricular tachycardia.

The use of intravenous tetrandrine on paroxysmal supraventricular tachycardia (PSVT) in 32 episodes of 27 cases were studied. The single blind test was done by injecting normal saline as placebo for self-control. Ambulatory ECG was recorded continuously. The dose of tetrandrine ranged from 0.12 to 0.21 g. The success rates of conversion of the placebo and tetrandrine were 3.1% and 83.9% respectively, being statistically significant (P less than 0.001). The efficacy of tetrandrine was comparable to that of verapamil (85%). In 4 cases of WPW syndrome one was converted by the placebo, the other 3 by tetrandrine. Those who did not respond to tetrandrine were mostly suffering from organic heart disease and were supposed to have automatic atrial tachycardia. The time needed for conversion ranged from immediacy after intravenous injection to 20 minutes, with an average of 4.6 minutes. The ECG changes of the termination of PSVT were similar to that of verapamil and can be explained as the effect of slow channel antagonists. Tetrandrine may be an alternative to verapamil in the treatment of PSVT.

Adolescent↗
PubMed1989

Spontaneous variability of premature ventricular complexes and its significance in assessing anti-arrhythmic drug efficacy.

Using ambulatory electrocardiography (AE), the spontaneous variability in 40 cases of chronic stable premature ventricular complexes (PVCs) was studied. The mean hourly PVC frequencies over 24 hours ranged 2-1 682. When analysing pooled data, there was significant variance between different monitoring periods and between patients as well. The most appropriate duration of AE recording was found to be 24 hours. The lower the mean hourly PVC frequencies, the bigger the coefficient of variation. Using linean regression analysis, the reduction of PVC frequency attributable to spontaneous variability with 95% confidence intervals ranged from 59 to 81% being related to the number of hospitalization days. Clinically, to evaluate antiarrhythmic drug efficacy, one should assess the reduction in PVC frequency of spontaneous variability advance, and a greater reduction rate is required to be considered as true drug effect. The previous fixed standard for assessing an antiarrhythmic drug response is no longer advisable.

Adult↗
PubMedDate not supplied

A stable ovine congestive heart failure model. A suitable substrate for left ventricular assist device assessment.

Similarities in coronary circulation and heart size of sheep to that of humans are specific advantages of a sheep model of congestive heart failure (CHF). CHF was created in 11 sheep (51 +/- 4 kg) by selective sequential intracoronary injection of 90 microns microspheres under 1.5% isoflurane anesthesia. Hemodynamic characteristics were assessed at baseline, 4 weeks after establishment of CHF (ejection fraction [EF] < 35%, n = 11), and 26 weeks (n = 7) later. Baseline echocardiographic EF was 59 +/- 5% and fell to 26 +/- 5% after 5 +/- 2 embolizations. The left ventricular (LV) pressure-volume relationship showed stable decreases in LV end-systolic elastance (Ees) and preload recruitable stroke work. Intravenous infusion of dobutamine increased Ees from 2.8 +/- 1.7 to 4.3 +/- 2.2 and 4.5 +/- 1.4 mmHg/ml at heart rates of 140 and 160/min, respectively, at baseline. Increases of Ees (from 1.3 +/- 0.5 to 2.3 +/- 0.7 and 1.9 +/- 0.5 mmHg/ml at heart rates of 140 and 160/min, respectively) with dobutamine under CHF conditions did not exceed Ees values at baseline without dobutamine. This response to dobutamine infusion did not change 26 weeks after establishment of CHF. This stable ovine CHF model is proposed for studies on the long-term effects of cardiac assist devices.

Animals↗