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Biomedical subjects

C H Yan

Publications and source records attributed to C H Yan.

18 recordsLinked to original sources
PubMed1994

[Reference values for blood, hair, and organ selenium levels in adults of Beijing].

Two hundred and four blood specimens and 202 hair specimens, and 72 tissue specimens of heart, liver, spleen, lung, kidney, muscle and skeleton from adults living in Beijing suddenly died were collected during 1990-1991. Selenium levels were determined by 2,3-diamine naphthalene fluorescence method with serum, human hair and calf liver as standard references to assure the quality of determination, and their reference values for adults in Beijing were established. Selenium nutritional status of the adults was evaluated preliminarily. Dietary selenium intake was estimated based on serum selenium levels, and the body total selenium content was estimated by biological monitoring.

Adolescent↗
PubMed1994

[Effects of methylflavonolamine hydrochloride on tension and cAMP of isolated guinea pig trachea].

Effects of methylflavonolamine (4'-methyl-7-(2-hydroxy-3-isopropylaminopropoxy)-flavone hydrochloride, MFA) on the tension and cAMP content of isolated guinea pig tracheal smooth muscle strips were studied. MFA (0.03-0.6 mmol.L-1) dose-dependently reduced KCl, acetylcholine (ACh) and histamine (Hist)-induced contractions with intracellular increase in cyclic AMP. The reduction in contraction and increase in cAMP were well correlated positively. MFA (0.03 mmol.L-1) showed synergism with isoprenaline (Iso) and aminophylline (Ami) in bronchodilation. The synergism with Iso but not Ami was accompanied by an increase in cAMP levels. It is suggested that the MFA-induced bronchodilation is related to the increase in intracellular cAMP level. The calcium antagonistic effect may be involved in MFA-induced bronchodilation.

Aminophylline↗
PubMed1992

[Effects of methylflavonolamine hydrochloride on contractility of isolated rabbit ileum].

Methylflavonolamine hydrochloride (MFA), verapamil (Ver), and trifluoperazine (Tri) inhibited the contractions induced by submaximal concentrations of acetylcholine (ACh) and serotonin (5-HT). IC50 values (mumol.L-1) were 33.2 +/- 0.7, 0.276 +/- 0.018, 3.83 +/- 0.23, and 15.31 +/- 0.10, 0.233 +/- 0.017, 2.33 +/- 0.20, respectively. MFA, Ver, and Tri inhibited the contractions induced by CaCl2 and pD'2 values were 4.3 +/- 0.3, 6.23 +/- 0.22, 4.99 +/- 0.24, respectively. MFA 3 mumol.L-1, Ver 0.03 mumol.L-1, and Tri 3 mumol.L-1 inhibited the contractions induced by ACh in Ca(2+)-free medium, while MFA 60 mumol.L-1, Tri 30 mumol.L-1, but not Ver 0.6 mumol.L-1, had pronounced inhibitions on extracellular calcium-dependent contractions induced by ACh. These results suggest that MFA has a calcium antagonistic effect and that MFA is similar to Tri, but not Ver, in mechanism.

Animals↗
PubMed1991

Spontaneous coronary artery dissection in a young man with anterior myocardial infarction.

A case of spontaneous coronary artery dissection in a young male with subsequent myocardial infarction is reported. In addition, distal vessel occlusion is noted, presumably from embolization of thrombotic material originating from the site of dissection. Postulated mechanisms of this uncommon cause of myocardial infarction and subsequent therapeutic options are reviewed.

Adult↗
PubMed1991

Anticancer gelatin microspheres with multiple functions.

Biodegradable, hydrophilic gelatin microspheres (GM) with an average diameter of 70 microns were prepared by cross-linking gelatin with glutaraldehyde for hepatic intra-arterial infusion. An anticancer agent, mitomycin C (MMC), together with a radioisotope, 131I, were bound to the GM for chemotherapy and local internal radiotherapy. The 131I-labelled MMC-GM (131I-MMC-GM) could accumulate in the specific site and embolize the hepatic arteries after the hepatic intra-arterial infusion, while it caused various effects to the liver cells. The 131I-MMC-GM remained within the hepatic arteries for at least one month. In vitro release of drugs from the GM was also quantified using a dynamic dialysis method.

Animals↗
PubMed1989

Direct examination of chemical kinetic laws by visual imagery. IV. Association processes between antigen- and fragmented antibody carrying fluorescent latex particles.

The binary association process was further examined by direct visual observation using a fluorescence microscope connected to an image-processing system and by a spectrophotometric method. In the present paper, we used human serum albumin (HSA)- and fragmented anti-HSA antibody-carrying fluorescent latex particles in order to attain higher sensitivities and exclude complexities that might be caused by dissociation of the association product. The rate constant of the binary association process was estimated to be 6.0 x 10(8) M-1 s-1 at 30 degrees C and pH 7.6. The activation parameters of the association process were evaluated. The effects of pH and viscosity of the suspension on the association process were also examined.

Antigen-Antibody Complex↗
PubMed1989

[The significance of mummy cell in the diagnosis of Hodgkin's disease].

The mummy cell is a necrotic single cell in lympho-reticular lesion, and it is characterized by the pattern of distributing isolated in a lympho-reticular background without detachment from the surrounding cells, staining deeply or amphibic in mature both nuclei and cytoplasm and the ghost nuclei are often recognized. Totally, 95 lympho-node biopsies were reviewed, the mummy cells can be found in 21/24 of Hodgkin's disease and 18/71 of other lesions (NHL, reactive hyperplasia etc.). They are more common in nodular sclerosis (NS) and lymphocyte depletion (LD) among the four subtypes of Hodgkin's disease. It is worthwhile to note the suggestive role of mummy cells in pathological diagnosis of Hodgkin's disease.

Hodgkin Disease↗
PubMed1989

[Blood gas analysis of varicocele, spermatic vein and peripheral vein].

Blood gas analysis was carried out in 80 cases of varicocele. The PO2 of the spermatic vein was lower than that of peripheral vein (P less than 0.01). There was also a significant difference of PO2 between I. and III. of varicocele (P less than 0.05). Blood of the spermatic vein showed metabolic acidosis. It is suggested that hypoxemia of the testes may affect spermatogenic function.

Adolescent↗
PubMed1988

Functional properties of proteins immobilized on albumin microspheres.

Bovine serum albumin (BSA) microspheres with an average diameter of 12.5 micron were prepared by crosslinking of BSA molecules with glutaraldehyde in the presence of polymethylmethacrylate dissolved in chloroform-toluene. Trypsin and anti-human IgG antibody were immobilized onto their surfaces by the glutaraldehyde-activation method. The catalytic activity and storage stability of the immobilized trypsin were satisfactorily high. The enzyme immunoassay (EIA) method using BSA-microspheres as a solid phase has a high sensitivity (the minimum concentration of detectable antigen in the sample: 0.2 ng/ml) and a wide concentration range (final concentration 0.027-3000 ng/ml) for the detection of human IgG.

Enzyme-Linked Immunosorbent Assay↗