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Biomedical subjects

S M Yang

Publications and source records attributed to S M Yang.

At least 19 recordsLinked to original sources
PubMed1991

The effects of atropine on pharmacokinetics of theophylline in rabbits.

The effects of atropine on serum concentrations and pharmacokinetics of theophylline were studied in six rabbits (2.07 +/- 0.11 kg). Theophylline serum concentration was determined by ultraviolet spectrophotometry. After i.v. administration of aminophylline 12.5 mg/kg, i.m. atropine 1 mg/kg decreased significantly the maximal serum concentration of theophylline from 23.6 +/- 1.1 to 19.6 +/- 1.1 mg/l, and increased that of theophylline at the time of 6 and 8 hours after injection. After i.v. aminophylline administration without or with atropine, the pharmacokinetic parameters of theophylline calculated using a one compartment open model were: K (elimination rate constant) = 0.23 +/- 0.03, 0.19 +/- 0.02/h; t1/2 (half life) = 3.04 +/- 0.40, 3.66 +/- 0.40 h; Cl (clearance) = 0.26 +/- 0.04, 0.23 +/- 0.03 l/kg/h, respectively (P less than 0.01). But there was no significant variation in modification of volume of distribution (Vd). The results suggested that there is a significant drug interaction between atropine and theophylline.

Animals↗
PubMed1990

Up-regulation of androgen receptor binding in male rat fat pad adipose precursor cells exposed to testosterone: study in a whole cell assay system.

Binding of androgens to adipocytes has previously been evaluated using cytosol fractions without taking into account nuclear binding, although the latter is suggested to be close to the physiological site of action. In the present study, performed in differentiated fat pad adipose precursor cells, we describe a simple, reliable and reproducible androgen binding assay in a system with intact cells. Tritiated and unlabeled methyltrienolone (R1881) were used to define specific and unspecific androgen binding. Triamcinolone acetonide was added to prevent the binding of R1881 to other types of receptors. Differentiated adipose precursor cells contain a homogeneous class of high affinity androgen binding sites, and binding is saturable and reversible. Binding apparently occurs at one site, with a Kd in the range of physiological androgen concentration (about 4 nM). Competition studies indicate that the receptor is specific for R1881, testosterone and dihydrotestosterone, which have approximately the same affinity, while progesterone, estradiol and dexamethasone show much lower affinity. Androgen binding was markedly enhanced after cellular exposure to R1881 and testosterone but not dihydrotestosterone, and this increase was dependent on protein synthesis, suggesting the formation of new receptors by these androgens. In conclusion, fully differentiated adipocytes contain a specific, high affinity receptor, the density of which is dependent on androgens.

Adipose Tissue↗
PubMed1990

Identification of cyclic metabolites of isopropylated phenyl phosphates in rabbit bile.

Some organophosphorous compounds, especially tri-o-cresylphosphate (TOCP), induce delay neuropathy. The cyclic saligenin phosphate (PSP) has been suggested to be the active metabolite of the protoxicant TOCP. The o-isopropylated triphenyl phosphates have been proven not to be neurotoxic. Studying the metabolism of these compounds we found the following cyclic metabolites: 2-phenyl-4H-4,4-dimethyl-1,1,3,2-benzodioxaphosphoran-2-oxide and 2-(o-isopropylphenyl)-4H-4,4-dimethyl-1,1,3,2-benzodioxaphospho ran-2-oxide. Additionally, monohydroxylated metabolites of the parent esters were detectable. The effect of glucuronidation on the formation of the cyclic metabolites is discussed in this paper.

Animals↗
PubMed1990

[Oblique muscle dysfunction and cyclotropia].

The disc-fovea angle was calculated from the fundus photo by measuring the distance of fovea to the geometric center of the disc and the distance of fovea to the horizontal meridian through the disc center. The authors found the average disc-fovea angle of 40 normal individuals to be extorsion 7.43 degrees; and the diagnosis of cyclotropia was made for patients with extorsion over 14.20 degrees or intorsion, and those in whom the disc-fovea angle difference between both eyes was 8 degrees or over. In 9 cases of AV syndrome, 86% (12/14) of the V pattern cases associated with inferior oblique overaction were excyclotropic, and 75% (3/4) of the A pattern cases were incyclotropic. In 5 cases of superior oblique paresis, 86% (6/7) of the diseased eyes were excyclotropic, whether the function of the antagonistic was normal. The authors concluded that fundus photos could serve as a basis for diagnosis of cyclotropia.

Anthropometry↗
PubMed1990

[The retinal visual acuity of amblyopia].

The authors studied the relationship between the retinal visual acuity (grating acuity) and recognition acuity (E acuity) in 94 normal eyes and 169 amblyopic eyes with the results that the RVA in 84% of the normal eyes was the same as E acuity, while in 66% of the amblyopic eyes, especially the strabismic category, RVA was better than E acuity. RVA was not affected by the orientation (0 degrees, 45 degrees, 90 degrees, or 135 degrees) of the grating or the size of the light field (1.5 degrees or 3.5 degrees). Factors which could contribute to the difference between the RVA and the E acuity and the difference between strabismic and refractive amblyopia were discussed. It was put forward that grating acuity was reliable in the diagnosis of amblyopia.

Adolescent↗
PubMed1990

[The relationship between corneal dellen and tearfilm breakup time].

In 51 patients (102 eyes) after strabismus operation, the incidence of corneal dellen was 22.54%. The average preoperative tearfilm breakup time was 28.75 sec, while the postoperative BUT in the dellen formation group was markedly reduced from the average 23.22 sec to 8.61 sec. The incidence of dellen after rectus resection (47.75%) was much higher than that after rectus recession (5.13%). It was believed that elevation of the bulbar conjunctiva after operation disturbed stability of the precorneal tearfilm to result in reduced BUT and local desiccation of the cornea, leading to dellen formation.

Adolescent↗
PubMed1989

A preliminary study on the use of enzyme-linked immunosorbent assay (ELISA) for detection of Trichinella spiralis infections in dogs.

An enzyme-linked immunosorbent assay (ELISA) was developed to detect Trichinella spiralis infections in dogs using rabbit anti-canine IgG-horseradish peroxidase prepared according to the improved periodate method and an antigen purified from T. spiralis larvae by Sephadex G-200 chromatography. Sixty-six canine sera were tested for trichinosis by the ELISA and it showed a detection rate which was significantly higher than that by trichinoscopy. This antigen of T. spiralis appeared not to cross-react with the sera of dogs infected with Ancylostoma caninum or Taenia spp. A comparison of ortho-phenylenediamine and 5-amino-2-hydroxybenzoic acid as substrates in the ELISA did not reveal a significant difference. Pieces of filter paper saturated with a defined quantity of whole blood can be substituted for serum as a source material for the test. The relationship between worm burden and the absorbance value in ELISA is discussed.

Animals↗
PubMed1989

[Contrast sensitivity in amblyopia].

The contrast sensitivity function for sinusoid gratings of various spatial frequencies was determined for both eyes of 21 cases with unilateral amblyopia. The CSF of all amblyopic eyes except one was reduced in comparison with the non-amblyopic eye of the same person. The CS curve was depressed, especially with the middle and high spatial frequencies. The cut-off high frequency shifted toward to the left, as was the peak sensitivity. The changes in CSF with respect to different degrees of amblyopia, and the possible errors that could be made during the examination were also discussed.

Adolescent↗
PubMed1986

[Endocrine cells in gastric carcinoma].

A few endocrine cells were observed in 7 of 16 specimens of gastric carcinoma studied by electronmicroscopy. They were closely mixed with other types of tumor cells infiltrating into the stroma. Some endocrine cells contained both neuroendocrine and mucous granules. This conforms well to the hypothesis that the endocrine cells as well as other types of tumor cells in gastric carcinoma, originate from the endoderm. The endocrine cells and other varieties of tumor cells were found in both intestinal and diffuse types of gastric carcinoma. The heterogeneity and histogenesis of gastric carcinoma are discussed.

APUD Cells↗