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Biomedical subjects

X Yang

Publications and source records attributed to X Yang.

At least 1,099 records · Page 61Linked to original sources
PubMed1992

An essential Saccharomyces cerevisiae gene homologous to SNF2 encodes a helicase-related protein in a new family.

The Saccharomyces cerevisiae SNF2 gene affects the expression of many diversely regulated genes and has been implicated in transcriptional activation. We report here the cloning and characterization of STH1, a gene that is homologous to SNF2. STH1 is essential for mitotic growth and is functionally distinct from SNF2. A bifunctional STH1-beta-galactosidase protein is located in the nucleus. The predicted 155,914-Da STH1 protein is 72% identical to SNF2 over 661 amino acids and 46% identical over another stretch of 66 amino acids. Both STH1 and SNF2 contain a putative nucleoside triphosphate-binding site and sequences resembling the consensus helicase motifs. The large region of homology shared by STH1 and SNF2 is conserved among other eukaryotic proteins, and STH1 and SNF2 appear to define a novel family of proteins related to helicases.

Adenosine Triphosphatases↗
PubMed1992

Inherited congenital adrenal hyperplasia in the rabbit: absent cholesterol side-chain cleavage cytochrome P450 gene expression.

We investigated adrenal steroidogenic enzymes, their activity and mRNA expression, and in vitro biosynthesis of an enzyme in rabbits with congenital adrenal hyperplasia (CAH; weight: CAH, 19 +/- 5 mg/adrenal; normal, 2.7 +/- 1.0 mg/adrenal). Serum pregnenolone (delta 5-P) levels in CAH newborn rabbits (12-36 h) were normal (mean/range, 438/51-2191 ng/dl), but corticosterone levels were low [0.05 +/- 0.05 microgram/dl; P less than 0.001 vs. normal (0.66 +/- 0.57)]. Serum Na+ levels in CAH newborn rabbits were in the normal range (143 +/- 30 meq/liter), but K+ levels were elevated [7 +/- 1.1 meq/liter; P less than 0.05 vs. normal (5.9 +/- 0.6 meq/liter)]. Minced normal adrenal tissue incubated with [3H] cholesterol (30-100 pmol/flask) and ACTH (100 mU/flask) produced [3H]delta 5-P (newborn, 21 and 45 fmol/100 mg; adult, 3 and 5 fmol/100 mg) and [3H]corticosterone (newborn, 23 fmol/100 mg; adult, 11.3 fmol/100 mg), but CAH adrenals produced no product (less than 1.3 fmol/100 mg). Adrenal mitochondria from normal newborn rabbits produced delta 5-P (4.4-7 nmol/mg protein), but CAH adrenals did not, while CAH adrenal mitochondria demonstrated over 4 times greater 11 beta-hydroxylase activity. A Western blot of adrenal homogenate from normal newborn rabbits revealed a cholesterol side-chain cleavage cytochrome P450 (P450scc)-immunoreactive species (mol wt, 53 x 10(3), but this species was absent in CAH adrenals; CAH adrenals had a normal adrenodoxin and intensified 17 alpha-hydroxylase cytochrome P450 (P450(17)alpha) band compared to normal adrenals. In vitro translation of RNA in a cell-free rabbit reticulocyte lysate system containing [35S] methionine yielded a precursor P450scc protein (mol wt, 58.5 x 10(3)) with normal adrenal RNA, but not with CAH adrenal RNA. P450scc mRNA was detected in all normal adrenals, but was not detected in all CAH adrenals. 21-Hydroxylase cytochrome P450 mRNA expression was detected at a similar level in both normal and CAH adrenals. We conclude that CAH in the rabbit is caused by inherited absent P450scc gene expression. The clinical, pathological, and biochemical manifestations of P450scc deficiency in the rabbit are nearly identical to the human disorder. Increased 11 beta-hydroxylase activity and increased P450(17)alpha on Western blot of CAH adrenals indicate altered gene expression of other steroidogenic enzymes due to CAH. Further molecular analysis of the P450scc gene in this animal CAH model will facilitate understanding of P450scc deficiency CAH.

Adrenal Glands↗
PubMed1992

[Experimental study on monitor of microcirculation of random skin flaps and early division of their pedicles].

In a series of 30 random skin flaps formed in pigs, the skin capillary blood flow was measured with laser doppler flowmetry (LDF) pre-, and postoperatively and within 48 hours after pedicle division. The results showed that the change in the microcirculation can be divided into three phases: (1) rapid rising, (2) plateau, and (3) slow rising. The plateau stage may be considered as the critical period. Division of the flap before this "critical" period causes flap necrosis, while division after the period resulted in flap survival (100 percent). Comparison of preoperative and postoperative LDF values can be regarded as a reliable objective criterion for division of the pedicle.

Animals↗
PubMed1992

The effect of multi-glycosides of Tripterygium wilfordii Hook f. (GTW) on the survival time of cardiac allografts in rats.

Heterotopic heart transplantation was carried out in rats and the influence of multi-glycosides of Tripterygium wilfordii Hook f. (GTW) and a subtherapeutic dose of cyclosporine A (CsA) on the mean survival time (MST) of the cardiac allografts was investigated. The results showed that the MSTs of cardiac allografts in both the GTW and CsA-treated groups were significantly prolonged (P < 0.01 vs control). The rate of allograft rejection in the drug-treated groups was much lower than that in the control group.

Abdomen↗
PubMed1992

[Erythrocyte membrane band 3 protein and HCO3-/Cl- exchange function in cor pulmonale patients].

The changes of erythrocyte membrane band 3 protein, blood gases and electrolytes of intraerythrocyte and extra-erythrocyte were investigated in 3 groups: type I respiratory failure (group I, n = 36), type II respiratory failure (group II, n = 33) and control group (CG, n = 50). The distribution of band 3 protein was narrow and the staining intensity of band 3 protein was lower in the electrophotogram of group II. The relative composition of band 3 protein in group II was significantly lower than that in group I and CG (P less than 0.01). The intraerythrocyte HCO3- in group II was significantly higher than that in group I and CG (P less than 0.01), but the extra-erythrocyte Cl- in group II was significantly lower than that in group I and CG (P less than 0.01). These findings suggested that (1) The relative composition reduction of erythrocyte membrane band 3 protein and HCO3-/Cl- exchange restrain may be one of the reasons that aggravated CO2 retention and respiratory acidosis in cor pulmonale patients with type II respiratory failure. (2) Because there was hypochloremia in the most cor pulmonale patients with type II respiratory failure, it was necessary to supply them enough chloride in time, which could not only correct hypochloremia, but also accelerate the rate of HCO3-/Cl- exchange and promote to eliminate CO2.

Acidosis, Respiratory↗
PubMed1992

Miniature urea sensor based on H(+)-ion sensitive field effect transistor and its application in clinical analysis.

An urea-ENFET (Enzyme field effect transistor) probe was made by covering one of the grids of the dual ISFET (Ion sensitive field effect transistor) with a membrane of cross-linked bovine serum albumin (BSA)-urease and the other with cross-linked BSA, and the response characteristics of the probe was then tested through differential measurements. In different concentrations of phosphate buffer, the sensor responded to various concentrations of urea solution within 10-60s. From the calibration curve plotted on logarithmic scales a linear concentration range of 1.0-8.0 mg/dl was acquired, and the correlation coefficient and response sensitivity were 0.997 and 50mV/dec. (mg/dl), respectively. However, in dilute urea solution, the sensor responded linearly to the contents of urea over the range of concentration of 0.1-1.0 mg/dl with a correlation coefficient of 0.998 and a response sensitivity of 12-15mV/mg/dl. The standard deviation and the variation coefficient for 20 performances responding to 100mg/dl urea in 0.01M pH7.0 phosphate buffer were found to be 1.39mV and 1.44%, respectively. The urea-ENFET was used for the determination of BUN (Blood urea nitrogen) and the BUN values were compared with those determined by enzymatic method, the repression equation and correlation coefficient for 50 assays were y = -0.1272 + 0.9695x and r = 0.9912, respectively. When the urea-ENFET was used for determining urea either in buffer solution or in serum for 250 runs over a period of 1.5 months (the enzyme FET was stored at 4 degrees C between measurements during this period), the observed decrease of response sensitivity was only about 10%.(ABSTRACT TRUNCATED AT 250 WORDS)

Biosensing Techniques↗
PubMed1992

Reduction of infarct size with coronary venous retroperfusion.

BACKGROUND: The purpose of this study was to determine whether coronary venous retroperfusion with pressure-controlled intermittent coronary sinus occlusion (PICSO) alone and in combination with coronary venous substrate enhancement using L-glutamate would decrease ischemic damage after surgical revascularization for an acute coronary occlusion. METHODS AND RESULTS: In 40 pigs, the second and third diagonal vessels were occluded with snares for 90 minutes followed by 30 minutes of cardioplegic arrest and 180 minutes of reperfusion with the coronary snares released. During the period of coronary occlusion, 10 pigs received PICSO using a balloon-tipped triple-lumen catheter in the coronary sinus; 10 pigs received PICSO plus oxygenated blood transfused retrograde via the PICSO catheter (7 ml/min), 10 pigs received PICSO plus an oxygenated blood L-glutamate (13 mM) solution, and 10 pigs received neither PICSO, blood, nor L-glutamate through the coronary sinus (unmodified). Hearts treated with PICSO had higher wall motion scores (1.27 +/- 0.33 for unmodified, 2.40 +/- 0.40* for PICSO, 2.45 +/- 0.20* for PICSO plus blood, 2.85 +/- 0.30* for PICSO plus L-glutamate; *p < 0.05 from unmodified where 4 is normal to -1 is dyskinesia), lower area of necrosis-to-area of risk ratio using histochemical staining techniques (73 +/- 4% for unmodified, 27 +/- 4 for PICSO; 18 +/- 2* for PICSO plus blood, 12 +/- 1* PICSO plus L-glutamate; *p < 0.05 from unmodified), significantly less tissue acidosis (pH) compared with the unmodified group (pH, -0.41 +/- 0.13 for unmodified, -0.16 +/- 0.03* for PICSO, -0.19 +/- 0.02* for PICSO plus blood, -0.20 +/- 0.08* for PICSO plus L-glutamate; *p < 0.05 from unmodified). CONCLUSIONS: Coronary venous retroperfusion with PICSO alone and in combination with coronary venous substrate enhancement using L-glutamate significantly decreases ischemic damage during urgent surgical revascularization.

Angioplasty, Balloon, Coronary↗
PubMed1992

[Development of a database for registration of journals in the library of NIHS].

A database for registration and management of journals in the library of NIHS was developed using dBASE III PLUS software. The database was shown to be useful in searching for journals subscribed in the various divisions of NIHS and for those already expired. Additional data related to accounting on and arrangement of journals will help management of the library.

Database Management Systems↗
PubMed1992

Clinical and electrophysiologic studies of R61748 (transcainide): a new class Ic antiarrhythmic drug.

The electrophysiology and antiarrhythmic efficacy of R61748, a 4-OH metabolite of R54718 (transcainide), have been studied in patients and animal experiments. The results indicated that R61748 (1 mg/l) decreased the rate of rise of the transmembrane action potential (Vmax) by 40% and shortened the action potential duration (APD) by 10% in guinea-pig right ventricular papillary muscle. ERP/APD increased by 10%. The effect was dose-dependent. Clinical electrophysiologic studies (EPS) in 6 patients with ventricular premature beats showed that R61748 (0.1 mg/kg) prolonged PA duration by 30%, AH interval by 13% and HV duration by 24%. ECG revealed prolonged P duration by 16%, P-R interval by 16% and QRS duration by 17%. R61748 has also been used in 14 patients with idiopathic premature ventricular contraction (PVCs). PVCs were abolished in 6 patients and decreased more than 93% in 2 patients. The average reduction of PVCs was 80%. R61748 (0.075 mg/kg) abolished an episode of repetitive ventricular tachycardia in 1 patient. It is concluded that R61748 is a potent new class Ic antiarrhythmic agent with slow kinetics. R61748 is the 4-OH metabolite of R54718 (transcainide) (Stroobandt et al., 1987) which is a new class Ic antiarrhythmic agent. Up to now no reports have been published about R61748. This paper presents the initial studies of cellular and clinical electrophysiologic effects and the evaluation of antiarrhythmic efficacy of R61748.

Action Potentials↗
PubMed1992

[Technique of measuring esophageal pressure in rabbits and its application to measurement of pulmonary compliance and resistance].

Esophageal pressure (Pes) was measured under non-invasive condition by an esophageal balloon made by ourselves, and the optimal position of rabbits for measuring Pes was explored. The correspondence between Pes and pleural pressure (Ppl) was examined in rabbits during different depths of breathing with varied lengths of balloon and varied depths of insertion of balloon into the esophagus. The results showed that the amplitude of Pes only on supine position was higher than that on the left and right lateral and prone positions, but no significant difference was noticed among the 3 positions. The optimal balloon length was 4-6 cm. The optimal depth of insertion of balloon into the esophagus was 20 cm. The pulmonary dynamic compliance and pulmonary resistance were measured in 11 white rabbits with 5 cm balloon, 20 cm depth of insertion, on the left lateral position. The results were correspondent with other authors. No significant difference was noticed in repeated measurements on 8 of the 11 rabbits 5 days later.

Airway Resistance↗
PubMed1992

[A review on the chemical constituents of Annona plants].

The paper reviews the progress in the research on Annona plants, including the structure of chemical constituents, spectroscopic characteristics and physiological activities. A new kind of anticancer constituent is also introduced.

Alkaloids↗
PubMed1992

Skin test inhibition by astemizole.

For the purpose of evaluating the therapeutic effect of antihistamines, we have set up an assay method called the "Skin Test Inhibition Index" (STII). Twenty subjects with hay fever were given astemizole (10 mg/d) for 7 days. Skin titration tests were carried out before and after treatment. Significant inhibition of the skin test reaction by astemizole was demonstrated (STII = 91). Another group of 6 hay fever patients was given astemizole (10 mg/d) for 10 days, and STII was determined on days 5 and 10 and on days 7, 14 and 21 after treatment. STII were calculated as 12, 108, 90, 10 and 7, respectively. These results demonstrate that astemizole is a long-acting antihistamine.

Adult↗
PubMed1992

[Preliminary experimental and clinical study of the treatment of chronic renal insufficiency by granule of yi-qi bu-shen].

The effects of the granule of Yi-Qi Bu-Shen on the chronic renal insufficiency (CRI) was studied. 30 cases of CRI patients using the granule was compared with other 23 CRI patients by using Aldehyde-coating Oxidated Starch in same conditions. The effective rate of these 2 groups were 53, 3% and 42.9% respectively (P > 0.05). According to laboratory observation, the granule had the ability to reduce BUN, Scr, Ch, TG and increase Ccr, Hb. The granule also could relieve symptom of Kidney-deficiency. Animal experimental research suggested the granule had the function of reducing BUN, Scr and could improve pathological changes in rat kidneys. The conclusion were that the granule was effective on treating CRI and could postpone the progress of CRI.

Adenine↗
PubMed1992

[Identification of medicinal gualou (fruit-rind of Trichosanthes) and its mixed fruits in Sichuan].

Our investigation shows that in Sichuan Province there are 7 species of medicinal gualou (fruid-rind of Trichosanthes) and its confused fruits (6 species of Trichosanthes and 1 species of Citrullus), among which 2 species are included in the Chinese Pharmacopoeia. The drug and its confused fruits are similar in shape. This paper emphatically deals with the tissue identification of the above mentioned 7 species.

Drug Contamination↗
PubMed1992

Indoor air pollution and pulmonary function in children.

Pulmonary function in winter time in 1,343 school children aged 10-13 years was measured in four cities located in northern and southern part of China. The results showed that FVC, FEV1, PEF, V75, V50 and V25 in children living in homes with coal stoves were decreased by 1.5-10.7% compared with children living in homes with gas or LPG stoves in Chengde and Shanghai. In contrast to this, no significant difference in pulmonary function was found in Shenyang and Wuhan. It suggested that this phenomenon was related to indoor air pollution, and partly related to passive smoking or outdoor air pollution.

Air Pollution, Indoor↗