Search PubMed⌕ Search

Biomedical subjects

M Yang

Publications and source records attributed to M Yang.

At least 487 records · Page 27Linked to original sources
PubMed1990

[Studies on the hypoglycemic effect of ginseng polypeptide].

Ginseng polypeptide (GPP) isolated from the root of Panax ginseng C. A. Meyer was demonstrated to decrease the levels of blood sugar and liver glycogen when injected intravenously to rats at doses of 50-200 mg/kg without affecting total blood lipid. when mice were injected subcutaneously daily at doses of 50 and 100 mg/kg for 7 successive days, GPP was also found to decrease blood glucose and liver glycogen. In addition, GPP was found to decrease various experimental hyperglycemia induced by injection of adrenaline, glucose and alloxan. However, GPP exhibited inhibiting effect on the glycogen enhancement induced by glucose, but strengthening effect on the glycogen decrease induced by adrenaline. When the levels of blood total lipid and liver glycogen were increased by alloxan, GPP was shown to inhibit these changes except its lowering of blood sugar. The toxicity of GPP is very low, its iv LD50 for mice was found to be 1.62 +/- 0.130 g/kg.

Animals↗
PubMed1990

Medication compliance, antidepressant blood levels, and side effects in Southeast Asian patients.

A study of medication compliance, side effects, and clinical change with the use of antidepressants in 32 Southeast Asian refugee patients seen at an urban mental health center is reported. Patients met criteria for either major depressive episode, posttraumatic stress disorder, or both. Only five of the 32 patients who stated that they were taking their medications regularly had antidepressant blood levels in the therapeutic range. Another 10 patients had subtherapeutic levels and the remaining 17 had undetectable blood levels. Patients with therapeutic blood levels had fewer side effects (p = 0.049) than patients with undetectable blood levels. Blood levels tended (p = 0.070) to be correlated with clinical improvement. The authors discuss cultural attitudes of Southeast Asian refugee patients toward medication use and side effects that appear to influence medication compliance.

Adult↗
PubMed1990

[Enhancement of absorption of tetramethylpyrazine by synthetic borneol].

Sprague-Dawley rats were given ig tetramethylpyrazine phosphate (TMP) 5 mg/kg with or without previous borneol 5 mg/kg. The plasma TMP concentrations were analysed by GC method, and the data were treated by NONLIN program. The Cmax were 931 and 562 ng/ml, respectively, (P less than 0.01); while the AUC were 68,849 and 37,174, respectively, (P less than 0.05). It is suggested that the borneol enhances the absorption of the TMP but not in elimination.

Absorption↗
PubMed1989

Receptors for insulin and insulin-like growth factor-I in the human adrenal gland.

Human adrenal glands contain high-affinity receptors for insulin and insulin-like growth factor I (IGF-I). Comparative studies with rat, hamster and human adrenal membranes confirmed that IGF-I receptors are most abundant in rat and hamster adrenals, whereas insulin and IGF-I receptors are present in equivalent numbers in human adrenal glands. Covalent crosslinking studies revealed that the human adrenal gland IGF-I receptor binding subunit migrated on dodecyl sulfate polyacrylamide gels with Mr = 135,000, which is identical to the migration of IGF-I receptor binding subunits isolated from other tissues. Autoradiography of frozen human adrenal slices incubated with [125I]insulin showed prominent, displaceable binding of this radioligand to the zona reticularis, zona glomerulosa, vasculature and medulla; in contrast, [125I]IGF-I binding to human adrenal tissue was most prominent in the zona reticularis and negligible in the medullary region.

Adrenal Glands↗
PubMed1989

Arterial baroreceptor resetting: contributions of chronic and acute processes.

1. Pressure threshold (Pth) and suprathreshold pressure sensitivity (Sth) are important measures of the pressure-discharge characteristics of arterial baroreceptors. An in vitro preparation of the rat aortic arch-aortic nerve has been used to assess the influence of extracellular ion concentration, distensibility, smooth muscle activation and rapid resetting on single fibre baroreceptor discharge. 2. Changes in extracellular cations alter Pth and Sth in a reciprocal manner, suggesting that these two properties share common excitatory mechanisms probably at the level of membrane ion conductance channels. 3. During normal development and ageing in normotensive rats, Pth and blood pressure are fairly constant even during periods of greatly changing aortic distensibility. Sth increases progressively to maturity and then decreases somewhat with advanced age. 4. During hypertension, changes in distensibility in spontaneously hypertensive rats do not account for changes in Pth and Sth. 5. The capacity of arterial baroreceptors to rapidly reset during acute changes in the conditioning mean arterial pressure is not altered by chronic resetting, decreases in distensibility or by differences in the initial Pth or Sth of individual baroreceptors. 6. Within the maximal physiological or pathophysiological range, the prevailing or conditioning mean arterial pressure appears to be the most potent modulator of arterial baroreceptor discharge.

Aging↗
PubMed1989

Augmentation of labour: does oxytocin titration to achieve preset active contraction area values produce better obstetric outcome?

The value of quantifying active contraction area to guide oxytocin titration in augmentation of labour was investigated by a randomised trial. Sixty-eight nulliparae with slow progress of labour had oxytocin titrated to achieve preset "optimal" active contraction area or "optimal" frequency of contractions in a randomised manner. There was no difference in maternal characteristics of age and height, pre-augmentation period of observed labour or cervical dilatation at the onset of augmentation between the 2 groups. The maximum dose of oxytocin, post-augmentation period and the number of operative deliveries were similar. There was no difference in the mean birth weight of neonates, or in the number of neonates who had low Apgar score or acidotic cord arterial blood pH. Our results suggest that there may be no advantage in oxytocin titration to achieve preset "optimal" active contraction area compared with "optimal" frequency of uterine contractions in nulliparae with slow progress of labour.

Female↗
PubMed1989

Interaction among unitary spike trains: implications for whole nerve measurements.

Interaction among action potential trains was examined in electroneurograms (ENGs) from filaments containing several fibers. In an in vitro preparation, increasing aortic pressure generated trains of action potentials (spikes) from regularly discharging aortic baroreceptors. Multifiber records were electronically sorted, and spikes from each separate baroreceptor were identified. "True" discharge rates, measured as the instantaneous frequency of the sorted records, were compared with the results of three quantitation approaches commonly used for multifiber or whole nerve activity in mass ENGs: "spike" counts per unit time, ENG voltage integration, and normalizations of counts or integration. Even in ENGs containing only two active baroreceptors, numerous interactions of the two spike trains occurred. Of 33 paired recordings (66 baroreceptors), 77.3% of the individual baroreceptors had spike trains that could not be clearly discriminated because of interactions with signals from other baroreceptors. Virtually all baroreceptors (96.3%) in nine three-fiber ENGs (27 baroreceptors) showed evidence of missed spikes. Corrected or true spike rates were always greater than activity rates measured by simple counting. Similarity of discharge frequencies in the different baroreceptors was the most important determinant of the rate of voltage signal interaction. Simple count or integration methods underestimated slopes of pressure-response curves and peak activity values by 20-40% compared with sorted instantaneous frequency. Not all coincidence of action potentials in the ENG resulted in simple additions of peak voltages. We conclude that simple counting and integrative techniques substantially underestimate multifiber nerve activity and such quantitation techniques should be used cautiously, particularly in experimental comparisons across groups of animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1989

Depression and posttraumatic stress disorder in Southeast Asian refugees.

The authors report on 404 Southeast Asian refugees seen at a community clinic. Approximately three-quarters of these patients met DSM-III criteria for major depressive episode, and 14% had posttraumatic stress disorder. Complaints of pain and sleep disturbances were the predominant presenting symptoms. Most of the men were married, but more than 40% of the women were widowed. Between 15% and 30% of the patients reported specific traumatic experiences either in their homeland or during their escape. Widowhood and such traumatic experiences were positively correlated with more symptoms of depression and anxiety.

Acculturation↗
PubMed1989

Interaction between mitochondria and the nucleus.

The interaction between the mitochondrial and the nuclear genome is in part mediated by proteins (and possibly also RNAs) which are encoded in the nucleus and imported into mitochondria. We are beginning to understand how proteins can penetrate across both mitochondrial membranes and how some of these proteins can regulate the expression of specific mitochondrial genes.

Amino Acid Sequence↗
PubMed1989

[A study on traditional processing methods using drug juice].

The traditional processing with drug juice has a long history, rich contents, rigid regularities and a variety of method. It is one of the important processing methods in Chinese medicine. To systematize and make better use of the traditional methods of processing drug juices, this paper has conducted an investigation from such angles as historical background, approximate rules of composing and clinical application.

Drugs, Chinese Herbal↗
PubMed1989

[Differences in length and weight growth patterns between urban and rural infants].

Mixed longitudinal data of length and weight growth from 595 rural and 337 urban infants were analysed. Count models were fitted to the means of length and weight in different ages, sexes and feedings separately. The curve fitting to the data was rather satisfactory. Comparison of model parameters between urban and rural infants suggested that rural infants had a higher length level at birth but lower accelerative growth afterwards than urban ones, which was even more obvious in breast-fed infants. The difference in birth weight between them was not significant; and the urban infants had a faster linear growth velocity than rural ones. These results might be caused by the fact that food supplementing in urban infants was significantly earlier and better than in rural ones.

Body Height↗
PubMed1989

Carcinoid tumor of the testicle.

Carcinoid tumors commonly are found in the gastrointestinal tract; they rarely are found in the testicle. An illustrative case is presented and the entity discussed. Variables regarding prognosis are reviewed.

Adult↗
PubMed1988

Import of proteins into yeast mitochondria: the purified matrix processing protease contains two subunits which are encoded by the nuclear MAS1 and MAS2 genes.

We have purified the metalloprotease which is localized in the soluble matrix space of Saccharomyces cerevisiae mitochondria and cleaves the amino-terminal matrix-targeting sequences from imported mitochondrial precursor proteins. The enzyme consists of two loosely associated non-identical subunits of mol. wt 48,000 and 51,000, respectively. Attempts to separate the two subunits from each other caused loss of activity. The smaller subunit had been identified as the product of the nuclear MAS1 gene (Witte et al., 1988). The larger subunit is now identified as the product of the nuclear MAS2 gene.

Alcohol Dehydrogenase↗
PubMed1988

Distribution of receptors for insulin and insulin-like growth factor I (somatomedin C) in the adrenal gland.

Rat adrenal glands contain cell surface high-affinity receptors for several peptide hormones. Receptors for IGF-I were abundant in this tissue, but receptors for insulin were relatively scarce. The behavior of adrenal membrane IGF-I receptors in radioligand binding assays was similar to the behavior of IGF-I receptors from other tissues, with a KD congruent to 6.2 x 10(-9) M. Covalent cross-linking studies with [125I]IGF-I revealed an IGF-I receptor alpha-subunit with Mr congruent to 135,000 on dodecyl sulfate polyacrylamide gel electrophoresis under reducing conditions, as well as a smaller radiolabeled peptide, Mr = 116,000. In contrast, little binding of [125I]insulin to adrenal membranes was observed and no labeling occurred in cross-linking studies using [125I]insulin. These results contrast with the findings of whole-body autoradiographic studies that indicated substantial binding of [125I]insulin to adrenal glands and suggest that IGF-I, rather than insulin, may play a critical role in the growth and development of the adrenal gland.

Adrenal Glands↗
PubMed1988

High-frequency switching in Dictyostelium.

A high-frequency switching system is demonstrated to exist in Dictyostelium discoideum. Switch phenotypes are distinguished by colony morphology and include changes in developmental timing as well as blocks in morphogenesis. The switching system exhibits the following characteristics: (1) a "low" spontaneous frequency of switching (approximately 10(-2] in the parent strain; (2) stimulation of the basal level of switching roughly fivefold with low doses of ultraviolet light; (3) "high" spontaneous frequencies of switching (as high as 10(-1] in particular variant strains; (4) high spontaneous frequencies of interconvertibility between variant phenotypes; (5) high spontaneous frequencies of reversion to the wild-type phenotype; (6) a set of reproducible switch phenotypes; (7) heritability of switch phenotypes; and (8) a rough correlation between switch phenotype and switching frequency. The extraordinary similarity between the switching systems in D. discoideum and Candida albicans is discussed.

Dictyostelium↗
PubMed1988

Localization of Bacillus subtilis sacU(Hy) mutations to two linked genes with similarities to the conserved procaryotic family of two-component signalling systems.

Mutations in the sacU region have a pleiotropic phenotype. Certain mutations designated sacU(Hy), for example, express degradative enzymes at high levels, are able to sporulate in the presence of glucose, have severely reduced transformation efficiencies, and are nonmotile. We isolated and sequenced the sacU gene region of Bacillus subtilis. Two open reading frames were found in the sacU region, and sacU(Hy) mutations were localized to both of these open reading frames. The two open reading frames have similarities to two widespread families of proteins that mediate responses to environmental stimuli.

Amino Acid Sequence↗