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Biomedical subjects

E Koh

Publications and source records attributed to E Koh.

At least 73 records · Page 4Linked to original sources
PubMed1991

[Presence of circulating suppressive factor for muscarinic acetylcholine receptor in senile dementia].

Alzheimer's disease is one of the main causes of senile dementia. Although its pathogenesis is not clear, some evidence has revealed that the activity of acetylcholine receptor in the brains of these patients is decreased. In the present study, possible circulating factors, affecting the muscarinic acetylcholine receptor of the synaptic vesicle from the rat brain, were evaluated in the serum of 95 senile subjects (34 males and 61 females, mean +/- SD age of 77.5 +/- 8.6 years). The cognitive function of these subjects was assessed by their Mini-Mental State scores, and they subjects were divided into non-dementic-subjects with a score of 21 or more, or subjects with dementia with a score of 20 or less. The latter were further divided into senile dementia with Alzheimer type (SDAT) and vascular type dementia (VS) using Hatchinski's ischemic score. The mean suppression rate by the serum from the SDAT patients on the binding of tritiated quinuclidinyl benzilate (3H-QNB), an antagonist for muscarinic acetylcholine receptor, to the rat synaptic membrane, was 18.1 +/- 7.2% of the control value, which was significantly greater than that of the non-dementic subjects, (4.7 +/- 3.8%). However, that in the VD group (8.4 +/- 6.8%), was not significantly different from the control value. Moreover the suppression rate of the serum on 3H-QNB binding showed significant positive correlated with score for the Mini-Mental State (r = 0.480, p less than 0.01) in the SDAT group. These data support the hypothesis that circulating suppression factors may participate in the pathogenesis of SDAT.

Aged↗
PubMed1991

[Evaluation of coronary hemodynamics and coronary reserve in children with coronary sequelae of Kawasaki disease].

We measured coronary blood flow by the continuous thermodilution method during coronary sinus catheterization via the femoral vein, and evaluated coronary reserve based on the findings of coronary hemodynamics and myocardial metabolism during atrial pacing. The study subjects consisted of 31 pediatric cases with a history of Kawasaki disease. Among them, 19 had normal coronary angiograms (Group A), 8 had dilated coronary lesions (Group B), and 4 had stenotic coronary lesions (Group C) on selective left coronary angiograms. 1. Coronary blood flow at rest: There were no significant differences between Groups A and B. In Group C, slightly low values were obtained in 2 patients with obstruction or recanalization in the left anterior descending artery. 2. Rate of an increase in coronary blood flow during atrial pacing: It was significantly lower in 5 of 19 patients in Group A, in 2 of 8 in Group B, and in one of 4 in Group C. However, in 2 patients with lower coronary blood flow at rest, the rate of an increase in coronary blood flow during atrial pacing was higher. 3. Following atrial pacing, enhanced anaerobic metabolism was observed in 6 of 17 patients (Group A, 2 of 5; Group B, 2 of 8; Group C, 2 of 4) who showed a poor increase in coronary blood flow during atrial pacing. These results indicate that coronary reserve may decrease even in patients without any coronary sequelae of Kawasaki disease on selective coronary angiograms possibly because of inadequate imaging of the microcirculation, i.e., the problem of the pathologic process at the level of small intramyocardial arterioles. To investigate the coronary sequelae of Kawasaki disease, the evaluation of coronary hemodynamics and myocardial metabolism by coronary sinus catheterization before and after atrial pacing is highly recommended.

Adolescent↗
PubMed1991

[A case of infected solitary renal cyst treated with percutaneous puncture and drainage].

A 29-year-old woman was admitted to our clinic with the chief complaint of high fever and right CVA tenderness. Treatment with antibiotics had not been completely effective in another hospital and she was referred to our hospital for further examination and treatment. Computed tomographic (CT) scan and ultrasonogram showed a right renal cyst. Therefore, we punctured and drained continuously the infected renal cyst for 16 days by a transcutaneous route. At her 3-month postoperative evaluation by CT scan, the cystic space vanished completely. We reviewed 43 cases of infected solitary renal cyst including our case in the Japanese literature and discussed the etiology and the treatment modality of infected renal cyst.

Adult↗
PubMed1990

Participation of both intracellular free Ca2+ and protein kinase C in tonic vasoconstriction induced by prostaglandin F2 alpha.

The roles of intracellular free Ca2+ and protein kinase C in the tonic contraction induced by prostaglandin were studied. Prostaglandin F2 alpha induced tonic contraction of rat thoracic aorta in both control and Ca2(+)-free solution. Close correlations were observed between the contractile response of aortic strips and the changes in intracellular free Ca2+ concentration in vascular smooth muscle cells assessed with the fluorescent Ca2+ indicator fura 2, both in control and Ca2(+)-free solutions. Prostaglandin F2 alpha also enhanced the production of inositol 1,4,5-trisphosphate in vascular smooth muscle cells before the rise of the intracellular free Ca2+ concentration. Moreover, 1-(5-isoquinoline-sulfonyl)-2-methylpiperazine, an inhibitor of protein kinase C, inhibited the tonic contractions induced by PGF2 alpha and 12-O-tetradecanoyl phorbol-13-acetate, a direct activator of protein kinase C, at similar concentrations. These results suggest that both intracellular free Ca2+ and protein kinase C participate in prostaglandin F2 alpha-induced tonic contraction.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1990

Atrial septal aneurysm in infancy.

Thirteen infants were found to have atrial septal aneurysms (ASAs) on two-dimensional (2D) echocardiography and their characteristics and natural course have been studied by 2D Doppler echocardiography. Atrial septal aneurysm was accompanied by atrial septal defect (ASD) or other cardiac malformations in 12 of 13 patients, and as an isolated anomaly in one patient. Spontaneous closure of ASD by aneurysmal formation of the interatrial septum was observed in 10 patients. The aneurysms of all 13 patients showed a moderate reduction in size, 14 to 25 months (mean 18 months), after these aneurysms had been first diagnosed and 10 subsequently disappeared. It is likely that ASA occurring in infancy will develop in patients with spontaneous closure of an ASD, and that such an aneurysm has a tendency to regress as the patient grows up.

Echocardiography, Doppler↗
PubMed1990

Effects of 1,25-dihydroxyvitamin D3 on the syntheses of DNA and glycosaminoglycans by rat aortic smooth muscle cells in vitro.

Studies were made on the effects of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] on the syntheses of DNA and glycosaminoglycans (GAG) by rat aortic smooth muscle cells (SMC) in vitro. DNA synthesis in cell cultures without fetal calf serum (FCS) was stimulated by incubation for 24 hr with 1,25-(OH)2D3 at concentrations of more than 10(-12) M, stimulation being maximal at a concentration of 10(-8) M. On the other hand, GAG synthesis was inhibited dose-dependently by 1,25-(OH)2D3 at concentrations of more than 10(-11) M. Other vitamin D3 metabolites had similar, but weaker effects on the syntheses of DNA and GAG by SMC, which were proportional to their affinities for the 1,25-(OH)2D3 receptor. These effects of 1,25-(OH)2D3 were not seen after short-term incubation (1 hr). These findings suggested that 1,25-(OH)2D3 stimulated the proliferation of SMC independent of growth factors in FCS, and that its effects were dependent on its specific receptor. Excess 1,25-(OH)2D3 might cause arteriosclerosis not only by stimulating proliferation but also by suppressing GAG synthesis.

Animals↗
PubMed1990

Inverse relation between severity of psoriasis and serum 1,25-dihydroxy-vitamin D level.

The serum levels of calcium, inorganic phosphate, parathyroid hormone, calcitonin, 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were measured in 34 patients with psoriasis vulgaris and compared with the severity of skin lesions. Severity of psoriasis was evaluated by three indices, the area-severity index (ASI), the area index (AI) and the severity index (SI), determined as the product of the area and severity, the area, and the severity of the individual skin lesions, respectively. The mean basal levels of these serum parameters were within the normal range. ASI and SI showed significant inverse correlations (r = -0.387, P less than 0.05 and r = -0.638, P less than 0.01, respectively) with the serum level of 1,25-dihydroxyvitamin D, but not with any other serum parameters, but AI was not correlated with any of these serum parameters. These data suggest that psoriatic patients are not deficient in 1,25-dihydroxyvitamin D, but that development of this skin disease may be related to a slightly decreased level of active metabolites of vitamin D or abnormalities in the responsiveness of the skin cells to them.

Adolescent↗
PubMed1990

Effects of prostaglandin F2 alpha on the mobilization of cytosolic free calcium in vascular smooth muscle cells and on the tension of aortic strips from rats.

The possible mechanism of action of prostaglandin F2 alpha on vascular smooth muscle was investigated. Prostaglandin F2 alpha induced sustained tonic vasoconstriction of rat aortic strips, accompanied by rapid increase in the cytosolic free Ca2+ concentration [( Ca2+]i) in the vascular smooth muscle cells. Prostaglandin F2 alpha also evoked rapid increase in production of inositol 1,4,5,-trisphosphate (Ins-P3). Moreover, it increased release of Ca2+ from nonmitochondrial pools in digitonin-permeabilized vascular smooth muscle cells, although this effect was much weaker than that of Ins-P3. These results suggest that the sustained action of prostaglandin F2 alpha may involve not only a rise in [Ca2+]i mediated by Ins-P3, but also a direct stimulation of Ca2+ from intracellular stores.

Animals↗
PubMed1990

Comparison of the production of cyclic AMP in response to parathyroid hormone in fibroblasts from aged subjects and young subjects: lack of an age-dependent decrease.

An age-dependent effect on the ability to produce cyclic AMP in response to parathyroid hormone (PTH) stimulation was examined using culture skin fibroblasts from both young and elderly female subjects. The mean values of both absolute and comparative production of intracellular cyclic AMP due to various concentrations of PTH administration did not differ between the two age groups, although the mean serum PTH level was significantly higher in the elderly subjects. These results indicate that the decreased response of the target organ to PTH in aged subjects can be explained mainly by the decreased number of intact cells rather than a decreased response of individual cells to PTH.

Adolescent↗
PubMed1990

Improvement of semen characteristics after surgical repair of bilateral testicular varicocele as compared to unilateral varicocele patients.

The operative treatment for surgical repair of bilateral testicular varicoceles was evaluated in terms of the improvement achieved in the sperm density and percentage progressive motile sperm. These parameters were compared for 27 cases of bilateral varicocele diagnosed by palpation and subjected to bilateral high ligation of the internal spermatic vein and for 40 cases of left unilateral testicular varicocele. There were no significant differences in preoperative values (such as sperm density; progressive motile sperm; serum levels of luteinizing hormone, follicle-stimulating hormone, and testosterone; and Johnson's score count) between the bilateral and unilateral testicular varicocele groups. The improvement in postoperative sperm density in the cases with bilateral testicular varicocele was apparently less satisfactory than in the cases with testicular varicocele only on the left side.

Adult↗
PubMed1990

Testicular macromolecular synthesis in men with varicocele.

The synthesis of DNA, RNA, and protein by varicocele testes with spermatogenic dysfunction was studied by examination of the levels of incorporation of [3H]thymidine, [14C]uridine, and [14C]leucine into the testicular tissue at 31 degrees C in vitro. The results suggest that DNA synthesis by the testis with moderate tubular damage is impaired whereas synthesis of RNA and protein is not. The cell regenerative ability of the testis with moderate tubular damage may be poor in spite of the preservation of testicular cell RNA and protein synthesis.

Adult↗
PubMed1990

Testicular steroids in spermatic and peripheral veins after single injection of hCG in patients with varicocele.

To determine the function of Leydig cells in patients with varicocele, hCG-stimulated levels of progesterone (Prog), 17 alpha-Hydroxy-4-pregnene-3,20-dione (17OHP), 4-Androstene-3,17-dione (A-dione), testosterone (T), and estradiol-17 beta (E2) in both spermatic and peripheral veins were measured. Seventy-two patients with idiopathic varicocele were divided into four groups: patients in group 1 were untreated, whereas patients in groups 2, 3, and 4 were given a single i.m. injection of 10,000 IU hCG 24 h, 96 h, and 168 h before surgery, respectively. In the spermatic and peripheral veins, levels of Prog, 17OHP, and E2 showed peaks at 24 h, whereas levels of A-dione and T showed peaks at 96 h. Significant increases in the ratios of spermatic veins 17OHP to A-dione and 17OHP to T, and a significant decrease in the ratio of T to E2, was found 24 h following hCG treatment. These results demonstrate that, following hCG injection, there is a transient inhibition of testicular C17-20-lyase activity, probably mediated by E2, even in subfertile males with varicocele.

Adult↗
PubMed1990

[Biochemical, molecular biological and immunohistochemical studies on androgen receptors in human Leydig cells].

The possible existence of androgen receptors (ARs) in human Leydig cells was examined by means of a biochemical AR assay, Western blot analysis, Northern blot analysis and immunohistochemistry. Percoll gradients were utilized to isolate highly purified Leydig cells from human testicular tissue. After these cells were confirmed to retain their morphological and biochemical integrity, they were used for the AR assay, Western blot analysis and Northern blot analysis. ARs in the purified Leydig cells were measured using 3H-methyltrienolone as the labeled ligand. A high affinity AR was detected in total cell extracts of both purified Leydig cells and whole testicular tissues, but the Bmax was less in the former than the latter. In Western blot analysis with anti-human AR (hAR) monoclonal antibody, two bands, different in molecular weight, were positively stained. These two 97 kDa and 80 kDa proteins were thought to be the specific AR proteins which were translated from the first and second initiation site of hAR cDNA, respectively. Northern blot analysis of RNA from purified Leydig cells as well as RNAs from prostatic and total testicular tissues proved the presence of AR using the hAR cDNA probe, and showed that the molecular size of AR mRNA is about 9.5 kb. Immunoreactive ARs in the human testicular tissue with anti-hAR monoclonal antibody were found predominantly in the nuclei of Leydig cells, suggesting that ARs, like other steroid receptors, exist mainly in nuclei of them. These findings provided the evidence that ARs are present in human Leydig cells and suggested that some local auto-regulations may exist in the human testis.

Aged↗
PubMed1990

Nicorandil is a potent dilator of endothelin-induced vascular contraction.

Nicorandil, an antianginal drug, is known to open K+ channel and to increase cGMP production. The effects of nicorandil on vascular contraction induced by endothelin (ET), a potent newly discovered vasoconstrictor peptide, were investigated using helical strips from rat thoracic aorta. ET at a concentration of 5 x 10(-9) M induced strong and persistent contraction in the presence of extracellular Ca2+ and similar persistent but smaller contraction in the absence of extracellular Ca2+. Nicorandil at concentrations greater than 10(-7) M, strongly and dose-dependently inhibited ET-induced contraction in the presence of extracellular Ca2+. Nicorandil also suppressed ET-induced contraction in the presence of 10(-4) M methylene blue, an inhibitor of cGMP production, in the presence of extracellular Ca2+ but not in the absence of extracellular Ca2+. ET-induced contraction was also inhibited to lesser extents by the Ca2+ channel blockers nicardipine and verapamil. Nicorandil also strongly suppressed ET-induced increase in cytosolic free Ca2+ concentration in cultured vascular smooth muscle cells. These results suggest that nicorandil is a potent dilator of ET-induced vasoconstriction.

Animals↗
PubMed1990

Endothelin stimulates Na+/H+ exchange in vascular smooth muscle cells.

The effect of endothelin (ET) on the intracellular pH (pHi) of vascular smooth muscle cells (VSMC), was investigated using a fluorescent pH indicator 2',7'-bis(carboxyethyl)carboxyfluorescein (BCECF). ET at concentrations of over 10(-9) M caused dose-dependent transient acidification followed by Na(+)-dependent and amiloride-sensitive alkalization of the cells due to stimulation of Na+/H+ exchange. The alkalization induced by ET was Ca2(+)-dependent and was inhibited by a calcium channel blocker, nicardipine. Pretreatment with H-7, an inhibitor of protein kinase C, also inhibited the ET-induced cell alkalization. These results indicate that ET stimulates Na+/H+ exchange, resulting in alkalization of VSMC and that this ET-induced cell-alkalization is probably linked to Ca2+ influx and activation of protein kinase C.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1990

The action of low density lipoprotein on vascular smooth muscle cells involves increase in intracellular pH.

The effect of low density lipoprotein (LDL) on the intracellular pH (pHi) of vascular smooth muscle cells (VSMC) was investigated using a fluorescent pH indicator, 2',7'-bis(carboxyethyl)carboxyfluorescein (BCECF). LDL and apoprotein B (apo-B), a binding protein for the LDL receptor, caused transient acidification followed by Na(+)-dependent and amiloride-sensitive alkalization of the cells due to stimulation of Na+/H+ exchanger. NH4Cl also caused intracellular alkalization, but independently of extracellular Na+. LDL, apo-B and NH4Cl all stimulated thymidine incorporation. These results indicate that the binding of LDL to its receptor stimulates Na+/H+ exchanger, resulting in alkalization of VSMC and suggest that this may function as a massage in stimulation of DNA synthesis evoked by LDL.

Amiloride↗