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H Chin

Publications and source records attributed to H Chin.

69 records · Page 4Linked to original sources
PubMed1986

Glycoprotein properties of muscarinic acetylcholine receptors from bovine cerebral cortex.

Muscarinic acetylcholine receptors from bovine cerebral cortex were solubilized in digitonin for the subsequent determination of several biochemical properties. The digitonin-solubilized receptors were representative of the entire membrane-bound population of muscarinic receptors with respect to carbohydrate content, isoelectric point, and molecular weight. The glycoprotein nature of the solubilized receptors was demonstrated by their quantitative binding to wheat germ agglutinin-agarose. The presence of a bound antagonist did not decrease the extent of receptor binding to this lectin. Treatment of receptors with neuraminidase to remove N-acetylneuraminic acid residues reduced binding to wheat germ agglutinin-agarose by 40%; further treatment with endoglycosidases D and H, to remove all N-linked carbohydrate, decreased binding by a total of 67%. Removal of N-acetylneuraminic acid residues had no effect on agonist binding properties of the membrane-bound receptors. The carbohydrate-specific enzymes were further used to assess the contribution of carbohydrate to the isoelectric point and molecular weight of the receptor. Muscarinic receptors solubilized in either digitonin or Triton X-100 focused as one major species with a pI of 4.3. Neuraminidase treatment resulted in an increase of 0.17 units in the pI of the receptor. Muscarinic receptors labeled with the covalent muscarinic antagonist propylbenzilylcholine mustard migrated as a single major polypeptide with a molecular weight of 73,000 on sodium dodecyl sulfate-urea-polyacrylamide gels. The exclusion of urea from these gels severely retarded receptor mobility, indicating a strong tendency for aggregation of receptors in SDS. Removal of N-linked carbohydrate by endoglycosidase treatment reduced the molecular weight of the antagonist binding polypeptide by no more than 5%. These results demonstrate the glycoprotein nature of muscarinic receptors from mammalian cerebral cortex and provide evidence for their heterogeneity with respect to carbohydrate content.

Animals↗
PubMed1983

Evaluation of multidisciplinary treatment of bladder cancer, especially in chemoimmunotherapy (ADM and OK-432) as a consolidation therapy.

The relapse rate of bladder cancer (transitional cell Ca) is said to be about 45%-80% even after tumor resection. Multidisciplinary treatment was designed and studied to prevent such recurrence. This treatment was designed to have three steps: induction, consolidation, and maintenance therapy. Following surgical tumor removal, OK-432 and Adriamycin (ADM) were administered as consolidation therapy, followed by administration of PSK and carboquone (CQ) in small amounts as maintenance therapy continuously for about 3 years, and the course was observed. In both consolidation and maintenance groups various non-specific immunoparameters were superior in groups receiving combined immunotherapeutic agents. Thus, the use of immunotherapeutic agents in combination with chemotherapeutic agents was considered to be effective. The 3-year recurrence rate was only 8% in the multidisciplinary treatment group, while that in the non-multidisciplinary treatment group was 61%. This approach, especially with chemoimmunotherapy (ADM and OK-432) as a consolidation therapeutic mode, is therefore considered to be useful for the prevention of recurrence.

Adjuvants, Immunologic↗
PubMed1980

Adjuvant immunotherapy with a S. pyogenes preparation (OK432) in urogenital cancer patients.

We evaluated the immunostimulative activity of a Streptococcus pyogenes preparation (OK432) in 50 patients with urogenital carcinoma. Differential lymphocyte blastogenic response to mitogens and quantitation of the lymphocyte subpopulation bearing Fc receptor sites were the two immunoparameters used in this study to assess the status of the cancer-bearing host. Using these immunoparameters, we observed a pattern whereby a substantial deviation from unity in the mitogen reactive ratio and an increase in the number of IgGFcR+T cells were correlated with malignant progression; administration of the immunopotentiator OK432 had a marked effect on immunoparameters reflected by our assays, with a trend toward return to normal values with progression of immunotherapy.

Adult↗
PubMed1980

Fiber-type effects of castration on the cholinergic receptor population in skeletal muscle.

The effects of castration on the extensor digitorum longus, soleus and levator ani muscles of the adult male rat were examined. After castration, no change was observed in the number of sites or the binding affinity of [125I]-monoiodo-alpha-bungarotoxin to the nicotinic cholinergic receptor population of the slow fiber muscle (soleus). The two fast fiber muscles (extensor and levator) showed no change in binding affinity but a significant change in the number of sites. In these two fast fiber muscles, the number of sites begins to increase within the first few days after castration, peaks at 14 days and begins to decline. The results presented in this report demonstrate three major concepts: 1) influences on skeletal muscle mediated by one receptor population can change the characteristics of another receptor population; 2) at least some androgen effects on skeletal muscle are fiber type specific; and 3) the development of extrajunctional receptors is not solely the function of the nerve-muscle relationship.

Animals↗
PubMedDate not supplied

Activity of biotin-dependent and GABA metabolizing enzymes in chorionic villus samples: potential for 1st trimester prenatal diagnosis.

We have documented the presence of five mitochondrial enzymes in samples of chorionic villus tissue and measured the levels of activity. Three of the enzymes catalyse biotin-dependent reactions. These are propionyl-CoA carboxylase, 3-methylcrotonyl-CoA carboxylase and pyruvate carboxylase. The other enzymes, 4-aminobutyric acid aminotransferase and succinic semialdehyde dehydrogenase, are involved in the degradation of the central inhibitory neurotransmitter GABA. Distinct diseases in which there is deficiency of each of these enzymes have been documented in man. Significant levels of activity were observed for all five enzymes in chorionic villus tissue. This methodology should permit early prenatal diagnosis of deficiencies of these enzymes by chorionic villus biopsy in the first trimester.

4-Aminobutyrate Transaminase↗
PubMedDate not supplied

Forearm and wrist radiology: Part II.

The emergency physician must be well versed in diagnosing forearm and wrist injuries. Although many of these injuries are readily apparent, others require more sophistication to appreciate. Careful attention to radiographic findings given the assistance of a well-directed history and physical examination is imperative. Both the more common and the more subtle injuries will be discussed.

Carpal Bones↗
PubMedDate not supplied

Forearm and wrist radiology--Part I.

The emergency physician must be well versed in diagnosing forearm and wrist injuries. Although many of these injuries are readily apparent, others require more sophistication to appreciate. Careful attention to radiographic findings given the assistance of a well-directed history and physical examination is imperative. Both the more common and the more subtle injuries are discussed.

Carpal Bones↗
PubMedDate not supplied

Supine bicycle stress echocardiography versus tomographic thallium-201 exercise imaging for the detection of coronary artery disease.

To compare the accuracy of supine bicycle stress echocardiography (SBSE), a new technique for evaluating coronary disease during peak exercise, with tomographic thallium-201 exercise imaging (SPECT), 71 patients were evaluated by SBSE, SPECT, and coronary arteriography. Twenty patients had normal coronary vessels; 22 had single-vessel, 14 had double-vessel, and 15 had triple-vessel disease. There were no differences in sensitivity (90% vs 92%), specificity (80% vs 65%), and accuracy (87% vs 85%) between SBSE and SPECT for the group of 71 patients. The results were similar in patients with and without prior myocardial infarction and with single-, double-, or triple-vessel disease. There were no differences between SBSE and SPECT for disease detection for the group of 213 individual vessels in sensitivity (88% vs 80%), specificity (87% vs 84%), and accuracy (88% vs 82%), but SBSE was more sensitive for the left anterior descending artery (97% vs 82%, p < 0.005) and for arteries involved in triple-vessel disease (93% vs 69%, p < 0.01) and more specific for the right coronary artery (88% vs 66%, p < 0.01). Supine bicycle exercise was associated with significantly lower maximal heart rates than treadmill exercise but with significantly higher systolic and diastolic blood pressures. There were no differences in heart rate x systolic blood pressure. We conclude that SBSE and SPECT are equally reliable for coronary disease detection in patients and for evaluation of disease in specific arteries with the exception of SBSE's higher sensitivity for the left anterior descending artery and arteries involved in triple-vessel disease and higher specificity for the right coronary artery.

Coronary Disease↗
PubMedDate not supplied

Synovial T cell receptor heterogeneity in early arthritis.

Rheumatoid arthritis (RA) has been postulated to result from a synovial immune response to an unidentified antigen(s), which should be mirrored by the T cell response. Here we investigate the T cell receptor (TCR) repertoire in the synovial tissue of patients with arthritis of early to moderate duration. We developed a nested polymerase chain reaction (PCR) technique to examine the TCR repertoire of small biopsy specimens, and show that the method is highly sensitive. We apply this technique to synovial biopsies obtained from the knee joints of patients with early to moderate duration arthritis (average duration of arthritis 1 year, range 0. 02-2.75 years). We examined biopsies from 5 normal individuals, 32 RA patients, 7 patients with seronegative spondyloarthropathy (Sp), and 12 patients with undifferentiated arthritis (UA). TCR message was detectable in 4/5 normals, 15/32 RA, 5/7 Sp, and 8/11 UA biopsies, with sampling error likely accounting for most negative biopsies. The average numbers of TCR Vbetas detected per TCR-positive biopsy were 5.0 +/- 3.7 for normals, 12.7 +/- 8.4 for RA, 18.0 +/- 7.4 for Sp patients, and 14.4 +/- 10.2 for UA. Examination of TCR messages by single-stranded conformational polymorphism analysis showed similar proportions of dominant clones in the normals compared with the patients with inflammatory arthritis. Sequence analysis was performed on 33 dominant clones from 16 patients. Sequence alignment of the third hypervariable regions showed some evidence of disease-specific sequence clustering for Sp, while some RA sequences showed similarity to previously described motifs. These data indicate greater TCR heterogeneity in early Sp and UA compared with normal synovium. Disease-specific TCR sequences may occur in early RA and Sp.

Adult↗