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Biomedical subjects

M S Yang

Publications and source records attributed to M S Yang.

At least 73 records · Page 4Linked to original sources
PubMed1994

Hydrolysis of 2-oxoquazepam in alkaline solution.

2-Oxoquazepam [7-chloro-1-(N-2,2,2-trifluoroethyl)-5-(2'-fluorophenyl)-1,3- dihydro-2H-1,4-benzodiazepin-2-one, OQZ], a major pharmacologically active metabolite of quazepam, was hydrolyzed in NaOH solution to form a sodium salt of 2-(N-2,2,2-trifluoroethyl)amino-5-chloro-alpha-(2'- fluorophenylbenzylidene)glycine. The hydrolysis product was formed via a rapidly established acid-base equilibrium, followed by a rate-determining, ring-opening reaction involving two negatively charged ions. Following neutralization, the hydrolysis product was isolated by reversed-phase HPLC and subsequently identified by its UV-vis absorption and MS analyses. Kinetics of the hydrolysis reaction in acetonitrile/water mixture was studied by reversed-phase HPLC analysis as a function of water content, NaOH concentration, temperature, and ionic strength. In acetonitrile:0.05 N NaOH (1:1, v/v), the hydrolysis of OQZ had an energy of activation of 14.4 kcal/mol and at 25 degrees C (delta H++ = 13.8 kcal/mol, delta S++ = -31.2 cal/K/mol, and delta G++ = 23.1 kcal/mol).

Anti-Anxiety Agents↗
PubMed1994

Clinical measurement of antibodies against acetylcholine receptor (AchR), SOD and LPO in patients with myasthenia gravis (MG) before and after thymectomy.

The antibodies against acetylcholine receptor AchR and levels of SOD and LPO were measured in 11 patients with myasthenia gravis (MG), and the results were compared with normal controls and patients with diseases other than MG. The results showed that the antibodies against AchR were higher as compared with other groups before and after operation. The post-operative level of antibodies was obviously lower than the pre-operative value. An slight increase in SOD and significant decrease in mean value of LPO after surgery were noted. The possible mechanism was discussed.

Autoantibodies↗
PubMed1994

Effect of digested sewage sludge on the ventilation and coughing rates of two fresh water fish.

Addition of digested sewage sludge at concentrations of 2% and 10% (v/v) to the water increased coughing rate in big head and tilapia (P < 0.05). Ventilation rate was significantly decreased (P < 0.05) in big head and tilapia at sludge concentrations of 6% and 2% (v/v) respectively. Copper (Cu), cadmium (Cd) and zinc (Zn) are trace metals which are commonly found in sludge. Cu caused a significant increase (P < 0.05) in coughing rate in both tilapia and big head at concentrations of 0.3 and 0.2 microgram/ml respectively. Zn caused significant increase (P < 0.05) in coughing rate only in big head at 2 microgram/ml. Neither fish responded to Cd of up to 2 micrograms/ml in the water. However, when the levels of these trace metals in the digested sludge were measured, they were below that which can cause significant changes in the respiratory movements. Therefore, the changes in ventilation and coughing rates after addition of sludge may be due to the presence of substances other than these metals. The results of this experiment provides a guideline to control the level of sludge that can be used in rearing these fresh water fish in ponds.

Animals↗
PubMed1993

Independent actions of asparagine and high levels of free Ca2+ in the induction of ornithine decarboxylase.

During growth stimulation of cells, Ca2+ and amino acids of the A, ASC and N transport systems are important for the induction of ornithine decarboxylase (ODC, L-ornithine carboxylase, EC 4.1.1.17). In order to clarify the relationship between Ca2+ and amino acids, we studied the induction of ODC by asparagine under three different Ca2+ states in H-35 rat hepatoma cells. First, in normal cells, extracellular Ca2+ above 0.1 mM and 10 mM asparagine separately stimulated ODC activity and their effects were approximately additive. In these normal cells, asparagine could act in the absence of medium Ca2+. TMB-8, a sequestered-Ca2+ release antagonist, had no effect on ODC induction whilst the asparagine action is sensitive to treatment with W7, a Ca-calmodulin antagonist, or lanthanum, a Ca2+ antagonist. Secondly, in cells treated with 0.5 mM EGTA in Ca(2+)-free medium, the asparagine action on ODC induction was blocked but the inhibition could be reversed by the addition of Ca2+ to the medium. Thirdly, ionomycin treatment in the absence of medium Ca2+ did not block the asparagine effect. Furthermore, in ionomycin-treated cells, the presence of high levels of medium Ca2+ increased ODC activity, but this increase was additive to, and could not replace, the action of asparagine. Our results indicate that the asparagine action does not depend on an increase of intracellular free-Ca2+.

Animals↗
PubMed1992

[The functional assessment of chronic pain patients activity of daily living and psychosocial disability].

The purpose of this study was to investigate the impact of activity of daily living and psychosocial function in patients with chronic nonmalignant pain. From Jun. 1989 to Nov. 1989, one hundred and eleven cases were assessed by Sickness Impact Profile (SIP) and Taita Symptom Check List (TSCL) to evaluate the disabilities associated with chronic pain. Patients showed significant impairment in the functions of physical psychosocial work and recreational activities. It was also apparent that the psychosocial disabilities were more severe than physical disabilities. Specifically, they showed anxiety depression and significant somatization. Analysis by stepwise multiple regression indicates that sex age educational level employment status diagnosis and pain intensity were the significant influencing factors related to the disabilities of activity of daily living and psychosocial function. The results supported the validity of the SIP as a measurement of functional status with chronic pain patients. Specifically, the psychosocial dimension was significantly correlated with the psychological and psychosocial distress categories of the TSCL. Based upon its reliability validity breadth of assessment and ease of administration, the SIP appeared to be well suited for the assessment of patients with chronic pain and for evaluating the efficacy of multidisciplinary pain treatment.

Activities of Daily Living↗
PubMed1991

Surgical treatment of myasthenia gravis and evaluation of its efficacy.

This paper reports 30 cases of myasthenia gravis (MG) treated by thymectomy from 1965 to 1990 in our hospital. Of all the 30 cases of MG, peripheral blood lymphocyte subpopulation was determined in 10, and anti-acetylcholine receptor antibody titer in 6, before and after operation. The results demonstrated the efficacy of thymectomy against MG. We considered that with application of hormone before and after operation to regulate immune function of the body, and/or with plasma exchange to remiss symptoms, all the patients with generalized MG may be indicated for treatment by thymectomy. Indication of treatment does not depend on age, sex and the course of the disease. But radical operation, proper anesthesia and appropriate use of antibiotics may ensure safety of the operation and its curative effect.

Adolescent↗
PubMed1991

Subcellular localization and immunological detection of proteins encoded by the vir locus of Bordetella pertussis.

The DNA sequence of the central regulatory locus vir of Bordetella pertussis predicts that three gene products, BvgA, BvgB, and BvgC, are encoded. Features of the predicted primary structures of these proteins and their homology to other two-component systems suggest that BvgA is located in the cytoplasm, BvgB is located in the periplasm, and BvgC spans the inner membrane. We have used gene fusions to the phoA and lacZ genes of Escherichia coli to investigate the subcellular localization and membrane topology of these proteins. PhoA fusion proteins were also purified and used to raise antibodies that allowed visualization of the vir-encoded polypeptides by Western immunoblotting. Our results have largely confirmed the predictions of the DNA sequence, with the exception that BvgB and BvgC were found to constitute one larger protein that was homologous to the sensor class of two-component systems. We propose that this protein be named BvgS (for sensor) and that its gene be named bvgS.

Amino Acid Sequence↗
PubMed1991

Genetic and immunological studies on polypeptides encoded by the vir locus of Bordetella pertussis.

We report here the results of genetic and immunological studies of the vir locus of Bordetella pertussis. These studies have allowed the determination of the cellular compartment that each of the vir-encoded polypeptides occupies, and have allowed the detection of each of them in crude extracts of Bordetella pertussis cells. From these studies it can be seen that the vir locus encodes two polypeptides, one a transmembrane sensing and signalling protein and the second a cytoplasmic regulatory protein. These proteins belong to the family of bacterial regulatory proteins known as two-component systems. A simple model for signal transduction in this organism is put forward.

Bacterial Proteins↗
PubMed1989

Study on the immunity to measles in pre-school children.

One hundred and ninety-seven pre-school children, composed of 109 boys and 88 girls, who resided in a rural community in southern Taiwan were studied. The age range was from 6 months to 5 years old (y/o) and vaccination coverage was determined by home visits and the vaccination records of the health station. Immunological status was tested by an enzyme-linked immunosorbent assay (ELISA) to determine the positive rate of measles-specific IgG. The results were as follows: 1, vaccination coverage in the studied sample was 87.9%; 2, the educational level of fathers had a significant influence on vaccination; 3, the positive rate of measles antibody in the vaccinated children was 73.9%; 4, the measles immunity level in the studied sample was 67.8%; and 5, the positive rate of measles antibody, as analyzed by a stratified test, indicated that vaccination age, the current age, and the number of siblings were the significant influence factors. When adjusted to the above variables, it was found that the number of siblings was the significant influencing factor.

Age Factors↗
PubMed1987

Aluminum deposition in the central nervous system. Preferential accumulation in the hippocampus in weanling rats.

Simultaneous administration of 1,25-dihydroxyvitamin-D3, citrate, and aluminum-containing phosphate binders is frequently used in patients with chronic renal failure. In order to investigate whether citrate may represent a risk factor of aluminum intoxication, 16 Sprague-Dawley weanling rats were randomly assigned to four groups: 1,25-dihydroxyvitamin-D3 at 16 ng/kg/day was given to all groups except the control; in addition, two groups received either aluminum hydroxide at 160 mg elemental aluminum/kg/day, or aluminum citrate at 160 mg elemental aluminum/kg/day, respectively. The control group received only the vehicle. Extremely high aluminum concentrations were detected in the hippocampus of rats receiving aluminum compounds. This content of aluminum (microgram/g dry weight) was far higher than that found in other brain areas of the same animals (146.40 +/- 51.23 versus 4.49 +/- 0.62, P less than 0.001) as well as that detected in the hippocampus of the control animals (2.73 +/- 0.40). Thus, in non-uremic, weanling rats supplemented with 1,25-dihydroxyvitamin-D3, the administration of aluminum favors selective accumulation in the hippocampus. No differences between aluminum hydroxide and aluminum citrate administration were observed.

Aluminum↗
PubMed1986

Prognostic significance of ventricular CSF lactic acidosis in severe head injury.

Brain-tissue acidosis inferred by cerebrospinal fluid (CSF) lactic acidosis is considered to play an important role in the clinical course of severe head injury. Ventricular CSF lactate concentration was studied in 19 patients during the first 5 days after severe head injury. All patients were intubated, paralyzed, and artificially ventilated so that PaCO2 was kept at 33.2 +/- 5.0 mm Hg and PaO2 at 122 +/- 18 mm Hg (mean +/- standard deviation). The mean Glasgow Coma Scale score on admission was 5.73 +/- 2.42. The first CSF sample was drawn within 18 hours after head injury. Over the first 4 days postinjury, patients with a poor outcome had significantly higher ventricular CSF lactate levels than did those with moderate disabilities or a good outcome. Patients showing favorable outcome had a significant decrease in ventricular CSF lactate levels 48 hours after injury. This decrease was not observed in patients with a poor outcome. Increased ventricular CSF lactate concentration was also reliably associated with increased intracranial pressure (ICP). Ventricular CSF lactate levels did not correlate with the magnitude of intraventricular bleeding. Arterial and jugular venous blood lactate levels, although high after head injury, were usually lower than the levels in the ventricular CSF and reached a normal range by the 3rd day following head trauma. At that time, the ventricular CSF lactate concentration was still above normal in patients with a poor outcome but had decreased to normal in patients with moderate disabilities or a good outcome. Ventricular CSF pH did not generally correlate with the ventricular CSF lactate concentration in patients under controlled ventilation; however, in a few patients close to death or with ventricular infection, a correlation was noted. Ventricular CSF lactate levels were not related to cerebral blood flow. In this study, profiles of ventricular CSF lactate concentration are defined in relation to the patients' clinical course and outcome. High ventricular CSF lactate concentration is present within 18 hours after severe head injury. Its decrease to normal in the following 48 hours is a reliable sign of clinical improvement; however, ventricular CSF lactate levels that are persistently high or that increase over time indicate the patient's deterioration. Serial assessment of ventricular CSF for acid-base status and metabolites in head-injured patients with a ventricular catheter already placed for ICP monitoring is useful in the evaluation of prognosis and clinical course.

Acidosis, Lactic↗
PubMed1985

Regional brain metabolite levels following mild experimental head injury in the cat.

Glucose, adenosine triphosphate, phosphocreatine, and lactate levels in the cortex, striatum, diencephalon, hippocampus, cerebellum, and brain stem were measured in cats 1 hour after they were subjected to low-level (2 atm) fluid-percussion injury. Following injury, there was a mild but significant increase in lactate levels in the majority of regions studied. The hippocampus exhibited the highest percentage increase in lactate (fourfold). The cortical area directly under the trauma device showed a threefold lactate increase, while there was a twofold increase in other brain regions studied. Although there were consistent decreases in phosphocreatine levels, these decreases were significant only in the hippocampus (p less than 0.05). Glucose levels in all brain regions studied were no different from control levels at the time of study. The unchanged glucose levels, together with previous studies of identically injured cats showing that cerebral blood flow was unimpaired, suggest that excess lactate was not a consequence of cerebral ischemia. Rather, the increase in lactate levels may indicate that concussive injury can produce a mild derangement of brain energy metabolism in the absence of substrate limitations. This derangement may reflect altered mitochondrial function.

Adenosine Triphosphate↗
PubMed1985

Pharmacologic studies of central actions of zopiclone: influence on brain monoamines in rats under stressful condition.

In order to investigate the central action of zopiclone, the rat brain was divided into 8 regions and the changes in monoamines (MA) in each region were examined. The effect of zopiclone on stress was also examined from changes in brain monoamines under electro-footshock stress load in comparison with that of nitrazepam and flurazepam. The animals were decapitated at 1 h after administration of zopiclone, nitrazepam and flurazepam at each dose of 1 and 10 mg/kg (p.o.). No changes in MA at each region of the brain were noted, but the metabolite, homovanillic acid (HVA) was reduced at the cortex, hippocampus, hypothalamus and cerebellum. 5-hydroxyindoleacetic acid (5-HIAA) was reduced at the amygdala. Noradrenaline (NA) turnover accelerated by electro-footshock stress load was inhibited by zopiclone. From the results of this experiment, it was found that the effects of zopiclone on brain MA were similar to those of nitrazepam and flurazepam: inhibition of 5-HT turnover at the amygdala was common to these three compounds. This result suggests that zopiclone has similar pharmacological properties to benzodiazepines as an antianxiety agent.

Amygdala↗