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Biomedical subjects

T Kojima

Publications and source records attributed to T Kojima.

At least 793 records · Page 44Linked to original sources
PubMed1987

Inhibition by amiloride of contractile elements in smooth muscle of guinea pig taenia cecum and chicken gizzard.

The relaxant action of amiloride was investigated in the smooth muscles of guinea pig taenia ceci and chicken gizzard. Amiloride inhibited the contractions induced by high K+ (45.4 mM) and carbachol (10 microM) in the taenia with the concentrations needed to induce 50% inhibition (IC50) of approximately 41 microM. A prolonged incubation period (greater than 1 hr) was necessary to obtain the full inhibition of these contractions. The taenia gradually accumulated amiloride and the tissue/medium ratio exceeded 2.0 after a 120-min incubation period. Amiloride had no effect on the high K+-stimulated 45Ca++ uptake or the ATP content of the taenia. Amiloride inhibited the Ca++-induced contraction of the saponin-treated taenia with an IC50 of 186 microM. Amiloride (10-1000 microM) also inhibited superprecipitation and Mg++-adenosine triphosphatase activity of the gizzard native actomyosin as well as the phosphorylation of myosin light chain. The inhibition of the phosphorylation was antagonized competitively by ATP. Amiloride (1 mM) had no effect on the dephosphorylation of myosin light chain upon removal of Ca++ from reaction medium. Amiloride, at concentrations up to 1 mM, had not effect on calmodulin activity as monitored by the Ca++-calmodulin-activated erythrocyte membrane (Ca++ + Mg++)-adenosine triphosphatase and phosphodiesterase activities. In contrast to this, trifluoperazine inhibited the calmodulin activity at the concentration needed to inhibit the Ca++-induced contraction of the permeabilized taenia and the superprecipitation and the phosphorylation of myosin light chain of gizzard. We conclude that amiloride, unlike trifluoperazine, may inhibit directly the myosin light chain kinase activity to induce muscle relaxation.

Actomyosin↗
PubMed1987

Possible absence of common polymorphisms in coagulation factor IX gene in Japanese subjects.

Four distinct intragenic polymorphisms in the coagulation factor IX gene which have been reported to be important for family diagnosis of Caucasian hemophilia B were studied in 51 normal Japanese subjects (21 males and 30 females). High-molecular-weight DNA prepared from peripheral blood lymphocytes were digested with endonuclease, Ddel, Mspl, Taql or Xmnl, and were studied by Southern blot analysis with factor IX complementary DNA as a probe. None of the minor fragments produced by these enzymes was found in the normal Japanese DNA samples tested, although the probe detects minor allelic forms in control Caucasian DNA samples. Our data suggest that the frequent polymorphic sites found in Caucasians are possibly absent in the Japanese population.

Asian People↗
PubMed1987

Changes in serum glucose and serum growth hormone levels during pituitary surgery.

During transsphenoidal surgery, serum growth hormone (GH) and serum glucose levels were measured in five acromegalic patients with diabetes or glucose intolerance, three acromegalic patients without diabetes or glucose intolerance, and six patients with prolactinoma. Preoperative steroid administration produced a significant increase in serum glucose level in acromegalic patients with diabetes or glucose intolerance, whereas in the other two groups no significant change in serum glucose level was found. After surgery started, there was a statistically significant increase in serum glucose level above baseline levels in all three groups. Serum GH levels decreased after commencement of surgery in acromegalic patients, and tumor manipulation did not produce a statistically significant increase in serum GH levels. Simultaneous increases in serum glucose and serum GH levels upon tumor manipulation did not occur in any group. We conclude that preoperative steroid administration in patients with high serum levels of GH in association with diabetes or glucose intolerance increases serum glucose levels, and that, after commencement of surgery, GH has only a minor role in the changes of serum glucose levels.

Acromegaly↗
PubMed1987

Liquid chromatography with multichannel ultraviolet detection used for studying disorders of purine metabolism.

We used a reversed-phase "high-performance" liquid-chromatographic system equipped with a multichannel ultraviolet spectrometric detector and a micro-computer for analyzing urine samples from patients with disorders of purine metabolism. This system recorded a series of absorption-spectrum data from a single chromatographic run and stored them for subsequent analysis. Because the retention times and ultraviolet absorption spectra of the eluates were recorded simultaneously, identification of peaks was easy and quite accurate for simultaneous quantification of orotidine, adenine, hypoxanthine, uric acid, xanthine, allopurinol (4-hydroxypyrazolo[3,4-d]pyrimidine), oxypurinol (4,6-dihydroxypyrazolo[3,4-d]pyrimidine), inosine, and 2,8-dihydroxyadenine--compounds extremely difficult or even impossible to quantify simultaneously with a conventional single-wavelength spectrometer. We used this method to investigate purine metabolites in urines from a patient with hereditary xanthinuria, three patients with 2,8-dihydroxyadenine urolithiasis, and a gouty subject taking allopurinol.

Adenine↗