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Biomedical subjects

S H Yoon

Publications and source records attributed to S H Yoon.

85 records · Page 5Linked to original sources
PubMed1989

The action of histamine on the isolated stomach muscle of the cat.

The effect of histamine on contractile and electric activity was studied in the isolated stomach muscle strips of 138 cats. Histamine dose-dependently produced tonic and phasic contractions of the muscle preparations from the fundus and the corpus but only phasic contraction of the antral muscle preparations. The frequency of gastric slow waves (SWs) was also increased dose-dependently by histamine. The responses of muscle contractions and gastric SW frequency to histamine were completely blocked by pretreatment with pyrilamine (10(-6) M) and were significantly inhibited by atropine (10(-5) M) but not by cimetidine (10(-5) M), hexamethonium (10(-5) M), phentolamine (10(-5) M), or propranolol (10(-5) M). The inhibition by pyrilamine was competitive. Although atropine inhibited the effect of histamine significantly, it could not completely block the effect of histamine even at a high concentration (3 x 10(-5) M). It is concluded that histamine may participate in the regulation of gastric motility in the cat by acting on the H1 receptor to cause the release of acetylcholine and also other contractile substance(s).

Animals↗
PubMed1989

Presence of erythroid and nonerythroid spectrin transcripts in human lens and cerebellum.

Spectrin is a major protein of the red cell membrane, and is composed of alpha- and beta-subunits. While spectrin was initially thought to be specific for erythrocytes, similar, but nonidentical peptides have recently been identified in other tissues, including lens, suggesting the existence of a spectrin gene family. To study the nature of spectrin-like peptides in the lens, we examined the transcription of erythroid and nonerythroid spectrin in human lens and cerebellum by direct hybridization with known human alpha- and beta-spectrin cDNA (erythroid probes), as well as with a human alpha-fodrin cDNA (nonerythroid probe). Northern blots of poly(A)+ RNA from erythroid, as well as several nonerythroid cells, and the total RNA from lens, showed that the beta-spectrin cDNA probe hybridized to two distinct bands of 8.6 and 7.4 kb mRNA in human lens, and was present in abundance. The erythroid beta-spectrin 11 kb mRNA transcript was also found in the human cerebellum. The beta-spectrin transcripts from these nonerythroid tissues were found to have different sizes compared to the major erythroid 7.8 kb beta-spectrin mRNA. Human lens contained a 7.5 kb transcript of the erythroid alpha-spectrin subunit. In addition, the human lens was found to have a 7.2 kb alpha-fodrin transcript; while the cerebellum had an 8.5 kb alpha-fodrin mRNA, the same size as that found in other nonerythroid tissues. The abundance of erythroid and nonerythroid spectrin transcripts in lens was significantly greater than in any other tissues examined. These data show that the human lens has abundant erythroid alpha- and beta-spectrin transcripts, as well as a unique alpha-fodrin transcript.(ABSTRACT TRUNCATED AT 250 WORDS)

Blotting, Northern↗
PubMed1987

Isolation and characterization of cDNA clones for human erythrocyte beta-spectrin.

Spectrin is an important structural component of the membrane skeleton that underlies and supports the erythrocyte plasma membrane. It is composed of nonidentical alpha (Mr 240,000) and beta (Mr 220,000) subunits, each of which contains multiple homologous 106-amino acid segments. We report here the isolation and characterization of a human erythroid-specific beta-spectrin cDNA clone that encodes parts of the beta-9 through beta-12 repeat segments. This cDNA was used as a hybridization probe to assign the beta-spectrin gene to human chromosome 14 and to begin molecular analysis of the gene and its mRNA transcripts. RNA transfer blot analysis showed that the reticulocyte beta-spectrin mRNA is 7.8 kilobases in length. Southern blot analysis of genomic DNA revealed the presence of restriction fragment length polymorphisms (RFLPs) within the beta-spectrin gene locus. The isolation of human spectrin cDNA probes and the identification of closely linked RFLPs will facilitate analysis of mutant spectrin genes causing congenital hemolytic anemias associated with quantitative and qualitative spectrin abnormalities.

Amino Acid Sequence↗
PubMed1987

An objective method of pulse diagnosis.

One component of Oriental medical diagnosis is pulse diagnosis. To make this method more objective, three pressure transducers were positioned over the radial artery and the absolute pressure of 50, 100 and 150 g was applied at three positions to simulate the classical pulse diagnosis. The transient pressure changes at the same absolute pressure were recorded. The pressure changes at the three positions were not equal even when the same absolute pressure was applied. Pressures were compared in superficial and deep locations, right and left wrist. The largest deflection was considered as excess and the smallest as depletion in twelve meridians.

Diagnostic Techniques and Procedures↗
PubMed1986

Clinical study of objective pulse diagnosis.

The recording of the objective pulse diagnosis was performed and the meridian points were selected from this recording. The proper meridian points (five element points) according to the five element theory and the improper points (non-five element points) were stimulated. Pain threshold was elevated by the stimulation of five element points and not raised by non-five element points in a patient who had nasal polypectomy under acupuncture analgesia and also in 6 of 9 healthy volunteers. Naloxone reversal of elevated pain threshold was also observed in volunteers.

Acupuncture Therapy↗
PubMed1985

Characterization of a soluble form of the C3b/C4b receptor (CR1) in human plasma.

A radioimmunoassay with the use of soluble 125I-Fab monoclonal anti-CR1 and rabbit IgG anti-CR1 bound to Staphylococcus aureus particles was employed to detect and quantitate CR1 antigen in human plasma. Among 16 normal individuals the concentration of soluble CR1 in plasma ranged from 13 to 81 ng/ml, and a similar range of concentration was found in plasma from 15 patients having systemic lupus erythematosus (SLE). The amount of plasma CR1 in normal donors, but not in SLE patients, significantly correlated with the number of CR1 sites on erythrocytes (r = 0.90, p less than 0.001), and was 7.1% of the amount of receptor that was present on erythrocytes in blood. The concentration of soluble CR1 was not diminished by ultracentrifugation or ultrafiltration of plasma, was not affected by various modes of anti-coagulation or even by clotting of blood, and did not change during incubation of blood at 4 degrees C for up to 4 hr. On sucrose density gradient ultracentrifugation of plasma the CR1 was distributed as a broad peak that overlapped the plasma protein profile. The Mr of plasma CR1 was identical to that of erythrocyte CR1 when assessed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and immunoblotting. In addition, the plasma form of CR1 exhibited the same structural phenotype as did receptor from erythrocytes of the same individual. CR1 antigen purified from plasma was as active as CR1 from erythrocytes in promoting the cleavage by factor I of C3b to iC3b, C3c, and C3dg. Therefore, a functionally and structurally intact form of soluble CR1 resides in plasma.

Animals↗
PubMedDate not supplied

High production of D-tagatose, a potential sugar substitute, using immobilized L-arabinose isomerase.

An L-arabinose isomerase of Escherichia coli was immobilized using covalent binding to agarose to produce D-tagatose, a bulking sweetener that can be economically used as a sugar substitute. The immobilized L-arabinose isomerase stably produced an average of 7.5 g-tagatose/L.day for 7 days with a productivity exceeding that of the free enzyme (0.47 vs 0.30 mg/U.day). Using a scaled-up immobilized enzyme system, 99.9 g-tagatose/L was produced from galactose with 20% equilibrium in 48 h. The process was repeated two more times with production of 104.1 and 103.5 g-tagatose/L. D-Tagatose production using an immobilized L-arabinose isomerase has a high potential for commercial application.

Aldose-Ketose Isomerases↗