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Biomedical subjects

E Koh

Publications and source records attributed to E Koh.

At least 91 records · Page 5Linked to original sources
PubMed1990

Interleukin-6 stimulates c-myc expression and proliferation of cultured vascular smooth muscle cells.

The effects of interleukin-6 (IL-6), a cytokine recently found to be secreted by monocytes and macrophages, on c-myc expression and proliferation of cultured vascular smooth muscle cells (VSMC) were investigated. Treatment with IL-6 caused rapid increase in the c-myc mRNA level of VSMC. It also stimulated DNA synthesis and proliferation of the cells significantly and dose-dependently at concentrations of more than 10 U/ml. These results suggest that IL-6 may be important in the proliferation of VSMC, which is a key event in the development of arteriosclerosis, as a factor mediating immune cell-VSMC interaction.

Animals↗
PubMed1990

Microsurgical transvaso-vasostomy.

We report a case of an infertile man treated successfully with microsurgical transvaso-vasostomy. The patient had a normal testicle with an obstructed vas deferens on one side and an atrophied testicle with a normal vas on the other side. We anastomosed the proximal vas from the functioning testicle to the opposite intact vas through the median scrotal raphe. As a result, the patient fathered a child 16 months after operation.

Adult↗
PubMed1989

Comparison of effects of a potassium channel opener BRL34915, a specific potassium ionophore valinomycin and calcium channel blockers on endothelin-induced vascular contraction.

The effects of a potassium (K+) channel opener BRL34915 and a specific K+ ionophore valinomycin on vasoconstriction induced by endothelin (ET) were compared with those of calcium (Ca2+) channel blockers, nicardipine and verapamil, using helical strips from rat thoracic aorta. ET induced potent and persistent contraction in control solution and similar but smaller contraction in Ca2+-free solution. BRL34915 and valinomycin inhibited the ET-induced contraction dose-dependently in control solution, but not in Ca2+-free solution. The ET-induced contraction was also inhibited by nicardipine and verapamil, though less strongly. On the other hand, high K+ (35 mM)-induced vasoconstriction was strongly inhibited by nicardipine and verapamil, but not by BRL34915 or valinomycin. These results support the idea that the extracellular Ca2+-dependent component of the ET-induced contraction may be mediated by Ca2+ influx by a route other than voltage-dependent Ca2+-channels.

Animals↗
PubMed1989

Effects of valinomycin on calcium mobilization in vascular smooth muscle cells induced by angiotensin II.

The effect of the specific potassium (K+) ionophore valinomycin on increase in intracellular calcium concentration [( Ca2+]i) was studied in vascular smooth muscle cells (VSMC). Valinomycin at more than 10(-9) M dose-dependently suppressed phasic increase in [Ca2+]i in VSMC induced by angiotensin II (AII) in both control and Ca2+-free solution, indicating that it suppressed the release of Ca2+ from intracellular Ca2+ stores. Nicorandil and cromakalim, which are both K+ channel openers, also suppressed the increases in [Ca2+]i induced by AII in the Ca2+ free solution. However, valinomycin did not suppress AII-induced production of inositol 1,4,5-trisphosphate (IP3), which is known to mediate the release of Ca2+. These results indicate that decrease of intracellular K+ induced by valinomycin suppressed the release of Ca2+ from intracellular Ca2+ stores induced by IP3.

Angiotensin II↗
PubMed1989

Congenital atresia of the left coronary ostium: diagnosis and surgical treatment.

An 11-year-old girl with congenital atresia of the left coronary ostium underwent coronary artery bypass grafting using the internal mammary artery. Before surgery, the patient complained of syncope on exertion. Exercise electrocardiogram (ECG), two-dimensional echocardiogram, and 201Tl myocardial scintigram were useful in establishing the diagnosis. Selective coronary angiograms showed typical findings. Postoperative recovery was uneventful; exercise ECG and stress 201Tl myocardial scintigram demonstrated improvement. Internal mammary artery graft is probably better than a saphenous vein graft as a coronary artery bypass graft in childhood and adolescence because of the long-term patency of this type of graft.

Angiography↗
PubMed1989

Correlative changes of plasma renin activity and serum testosterone in human internal spermatic vein after single administration of human chorionic gonadotropin.

To study changes in renin secretion from the human testis at various days after hCG treatment, plasma renin activity in the internal spermatic vein (ISV) and cubital vein (CV) was measured at the time of surgical repair of varicocele in 79 patients. Sixty-five of them were given a single administration of hCG (10,000 IU/m2) 1 to 10 days before operation. Although the mean PRA levels in CV in both treated and untreated groups were similar, the mean PRA levels in ISV obtained 1 to 5 days after hCG treatment were significantly higher than that in the untreated group. However, the mean PRA levels in ISV returned to that in the untreated group 6-10 days after treatment. Serum testosterone levels in the same ISV were also much higher 1 to 6 days after hCG treatment, compared with those in the untreated group. On the basis of these results it is concluded that (a) the secretion of renin from the testis into ISV can be demonstrated for 5 days after hCG treatment; (b) the parallel increases in PRA with testosterone in ISV seem to suggest a possible influence of androgen on renin production in Leydig cells of human testis.

Adult↗
PubMed1989

Association of increased intracellular free Ca2+ by platelet-derived growth factor with mitogenesis but not with proteoglycan synthesis in chondrocytes--effect of suramin.

The effects of platelet-derived growth factor (PDGF) on the intracellular free Ca2+ concentration [( Ca2+]i) in chondrocytes were studied with a fluorescent Ca2+ indicator, fura 2, and compared with the effects of PDGF on mitogenesis and proteoglycan synthesis. PDGF evoked phasic and then tonic increase in [Ca2+]i dose-dependently in quiescent cultures of chondrocytes, and it also stimulated both DNA and proteoglycan syntheses dose-dependently similar to somatomedins. Suramin, which inhibits the interaction of PDGF with its receptors, caused dose-dependent inhibition of both the PDGF-evoked increase in [Ca2+]i and stimulation of DNA synthesis by PDGF. However, suramin rather enhanced the proteoglycan synthesis induced by PDGF without affecting the basal level of proteoglycan synthesis directly. These results suggest that [Ca2+]i may be an important signal for the action of PDGF on cell proliferation in chondrocytes, and that the initial signal for proteoglycan synthesis is different from that for DNA synthesis induced by PDGF after the activation of PDGF receptor.

Animals↗
PubMed1989

Relation between mixed venous blood oxygen saturation and cardiac pumping function at the acute phase of myocardial infarction.

In this study, we monitored changes in the mixed venous blood oxygen saturation (Sv-O2) level of 45 patients with acute myocardial infarction and compared these results to the traditional parameters. The Sv-O2 level was found to correlate well with the clinical course of patients and their hemodynamic conditions. The mean Sv-O2 level of the group having congestive heart failure (53.3 +/- 8.4%) was found to be statistically lower than those without (69.8 +/- 5.6). Furthermore, patients whose Sv-O2 level was lower than 60% were found to be at greater risk for heart failure and a very high mortality rate. Patients were classified into four subsets according to Forrester's hemodynamic classification; their Sv-O2 levels were 70.7 +/- 4.1% (I: 23 cases), 54.7 +/- 6.9% (II: 8 cases), 55.8 +/- 9.4% (III: 10 cases), and 47.0 +/- 8.0 (IV: 4 cases), respectively. A severe relationship between pulmonary capillary wedge pressure and Sv-O2 having a correlation coefficient of r = -0.64 was observed, and a logarithmic curvilinear relation between cardiac index approximately Sv-O2, stroke volume index approximately Sv-O2 and left ventricular stroke work index approximately Sv-O2 was also evident. When the decrease in the Sv-O2 level was more than 5%, it always showed a significant decrease in the cardiac index. This study suggested tht continuous monitoring of the Sv-O2 level revealed simultaneous changes in the hemodynamic state, which lead to the assistance and aid for treating patients with critical conditions of acute myocardial infarction. In such circumstances, it was noted that the Sv-O2 level should be maintained above 60% in order to stabilize the hemodynamic state.

Aged↗
PubMed1989

Circulating levels of calcitonin gene-related peptide in patients with medullary thyroid carcinoma.

Calcitonin gene-related peptide, originally found in rat medullary thyroid carcinoma cells, was measured by radioimmunoassay in plasma samples with added aprotinin from 17 normal volunteers and 21 patients with medullary thyroid carcinoma. The concentrations were below 75 pmol/l in all 17 normal subjects with a mean of 33 +/- 19 pmol/l plasma. In the patients, the plasma calcitonin gene-related peptide concentrations ranged from below 5 pmol/l to 236 pmol/l, although the mean (36 +/- 48 pmol/l) was not significantly different from the mean normal level. Increase in the plasma calcitonin gene-related peptide level was observed in 2 of 5 patients in response to infusion of 4.3 mg/kg of calcium for 10 minutes and in 3 of 5 patients in response to infusion of 4 micrograms/kg of tetragastrin for 5 minutes. These observations suggest that measurement of calcitonin gene-related peptide level may be helpful in determination of diseases in which the level of calcitonin is of less diagnostic value.

Adolescent↗
PubMed1989

DNA and RNA synthesis by postpubertal undescended testis in vitro.

To study the spermatogenic potential of postpubertal undescended testis, the 3H-thymidine and 14C-uridine incorporations into normally descended and inguinal undescended testes were examined. The results suggest that DNA synthesis by the inguinal undescended testis is remarkably inhibited but, on the contrary, RNA synthesis is not. The cell-proliferative ability of postpubertal undescended testis may be impaired in spite of the retention of cell viability in the testis.

Adult↗
PubMed1989

Impaired DNA synthesis by early pubertal cryptorchid testis in vitro.

To study the spermatogenic potential of the early pubertal cryptorchid testis, testicular DNA synthesis was examined in vitro. DNA synthesis by early pubertal cryptorchid testis was inhibited and lost its normal temperature sensitivity. The spermatogenic potential of the cryptorchid testis may be impaired as early as puberty.

Cryptorchidism↗
PubMed1989

In vitro responsiveness of human testicular DNA synthesis to gonadotropins.

To evaluate the responsiveness of spermatogenesis in the normal human testis to human menopausal gonadotropin (hMG) and human chorionic gonadotropin (hCG), the DNA synthesis of spermatogonia was investigated using 3H-thymidine uptake by cultured tissue fragments of human testis with or without treatment with hCG and/or hMG. Two groups treated with different concentrations of hCG showed no difference in 3H-thymidine incorporation into testicular tissue compared with untreated control. In two other groups treatment with combined hMG/hCG in different concentrations induced significant changes in 3H-thymidine incorporation compared with control (p less than 0.01, p less than 0.01). Combined hMG/hCG treatment was effective in inducing spermatogenesis by normal human testicular tissue.

Chorionic Gonadotropin↗
PubMed1989

Effectiveness of hMG-hCG treatment for DNA/RNA syntheses in subfertile human testis in vitro.

To evaluate the effect of hMG-hCG treatment on spermatogenic impairment, DNA/RNA syntheses were measured in 25 patients with idiopathic male infertility by estimating the values of 3H-thymidine and 14C-uridine incorporation into the testicular tissue cultured with or without the hormonal treatment. Without the hormonal treatment, the levels of 3H-thymidine incorporation were in inverse correlation with the progress of spermatogenic impairment, whereas disturbances in responsiveness to the hormonal treatment directly correlated with spermatogenic impairment. Although the 14C-uridine incorporation increased both with and without the hormonal treatment, the values showed different patterns from those of 3H-thymidine incorporation. It would appear that the DNA synthesis in testicular tissue cultured with or without hMG-hCG treatment might predict the responsiveness to hormonal treatment for patients with idiopathic male infertility.

Chorionic Gonadotropin↗
PubMed1989

Induction of testicular DNA synthesis in vitro by hCG and hMG treatments in men with hypogonadotropic hypogonadism.

To study the effectiveness of hCG and hMG administration on spermatogenesis of patients with hypogonadotropic hypogonadism (HH), the DNA synthesis of spermatogonia was investigated by the method of 3H-thymidine uptake by cultured tissue fragments of human testis with or without treatment with hCG and/or hMG. Although in two groups treated with different concentrations of hCG the value of 3H-thymidine incorporation into testicular tissue showed no significant difference compared with the untreated control group, treatment with both hCG and hMG induced significant changes in the value of 3H-thymidine incorporation compared with the untreated control group. Combined hCG and hMG therapy was effective for induction of spermatogenesis in patients with HH.

Adolescent↗
PubMed1989

Testicular FSH and hCG receptors in Sertoli-cell-only syndrome.

Testicular FSH and hCG receptors were measured in patients with Sertoli-cell-only syndrome (SCOS), and the value of Bmax for each hormone was compared with the value in subjects with normal testes. FSH receptor was detectable in only four of 10 patients, and the mean value of Bmax in four of the 10 patients was clearly lower than that in normal testes (p less than 0.005). On the other hand, hCG receptors were detected in all of six tested patients, and the mean value of Bmax was lower, but not remarkably so, than that in the normal testes. The function of Sertoli cells was remarkably impaired in most men with SCOS, whereas the function of Leydig cells was relatively preserved.

Adult↗
PubMed1989

Plasminogen activator activity of testicular cells of subfertile men and FSH in vitro.

SDS-polyacrylamide gel electrophoresis followed by enzymography of a human testicular cell culture medium demonstrated that the molecular weight of plasminogen activator (PA) secreted was similar to that of human urokinase and it was also confirmed that follicle-stimulating hormone (FSH) stimulated PA secretion. To further investigate the correlation between spermatogenic impairment and secretory potential of PA in human testicular cells in vivo, the maximum increment in PA activity as a result of treatment with ovine FSH was measured for two groups of patients with different degrees of spermatogenic impairment. The mean value of maximum increment in PA activity in one group with severely impaired testes was remarkably lower than that in another group with slightly impaired testes. Protein biosynthesis in human testicular cells dependent on FSH appears to be impaired with the progression of spermatogenic impairment.

Cells, Cultured↗