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Biomedical subjects

K Minoda

Publications and source records attributed to K Minoda.

At least 37 records · Page 2Linked to original sources
PubMed1990

Parental age and seasonal variation in the births of children with sporadic retinoblastoma: a mutation-epidemiologic study.

Statistical analysis of parental age data from 225 sporadic cases of bilateral retinoblastoma, plus ten sporadic cases of chromosome deletion or translocation involving 13q14 that was identified as of paternal origin, revealed no evidence of paternal or maternal age effect. Parental exposure to ionizing radiation or chemical mutagens, the effect of which is accumulated with advancing age, does not seem to play a major role in the production of germinal mutations at the responsible (RB) locus. Furthermore, analysis of variation in the month of birth of 753 children with sporadic unilateral retinoblastoma did not show any significant deviation from the controls or a cyclic trend. The occurrence of nonheritable retinoblastoma is not likely to be associated with certain viruses such as human adenovirus 12 whose activity varies markedly with season. These results, together with the fairly uniform pattern in the incidence of this tumor among different populations, suggest that most, if not all, cases of sporadic retinoblastoma are caused by some intrinsic biological mechanisms, and not by environmental mutagens that may vary with respect to time and place.

Adolescent↗
PubMed1990

Immunohistochemical studies of retinoblastoma.

Various immunohistochemical markers were detected in 27 cases of human retinoblastoma by immunohistochemical avidin-biotin-peroxidase complex and peroxidase-antiperoxidase techniques using mono- and polyclonal antibodies. The glial markers, glial fibrillary acidic protein and Leu-7, were detected in the natural retinal component and perivascular glial cells within the tumor mass. In 4 among 27 cases Leu-7 was positive in the glial cells which were interspersed randomly among tumor cells and not associated with blood vessels. The neural marker, neuron-specific enolase, stained strongly positive in undifferentiated tumor cells and weakly positive in rosettes and fleurettes in most of the cases (21/27). Opsin, the photoreceptor marker, which is present only in the outer segment of photoreceptor cells, was detected in tumor cells of fleurettes in one case and also in rosettes in 6 cases. These results support the view that retinoblastoma has a predominantly neuronal nature with significant photoreceptor-like differentiation and rarely glial differentiation.

Adult↗
PubMed1989

The N-myc gene product in primary retinoblastomas.

The N-myc gene product in retinoblastomas was examined using the antisera against the N-myc gene product, which was produced as a fusion protein by Escherichia coli. The N-myc gene product was detected not only in the retinoblastoma cell line Y79 but also in primary retinoblastomas as a pair of bands of approximately 62 kilodaltons (KD) by immunoblotting. Immunohistochemical analysis showed positively stained cells with the antibody against the N-myc gene product in a few rosettes or fleuretts containing area of the tumor. The nuclei of the cells were positively stained. The N-myc gene product was not detected in the normal part of the retina or in other parts of the eye. The results suggested that the level of the N-myc gene product may be inversely correlated with the differentiation of retinoblastoma cells and that the detection of the N-myc gene product may be useful in the diagnosis of retinoblastoma. Because the undifferentiated form of retinoblastoma carries a worse prognosis than the differentiated forms, the level of the N-myc gene product may be related to the aggressiveness of the tumor cells. It remains to be seen whether metastatic retinoblastoma has a higher concentration of the N-myc gene product.

Cell Line↗
PubMed1988

Effects of intracoronary injection of acetylcholine on coronary arterial hemodynamics and diameter.

To examine the effects of intracoronary injection of acetylcholine on coronary blood flow and on coronary arterial diameter in humans, acetylcholine was injected into the left coronary artery in 32 adult patients (21 men and 11 women with a mean age of 54 years, range 37 to 65) with normal or almost normal coronary arteriographic findings. Patients with angina pectoris, myocardial infarction and severe cardiac diseases were excluded. Temporary right ventricular pacing was set at a rate of 60 beats/min to prevent transient bradyarrhythmias during intracoronary injection of acetylcholine. Measurements of coronary sinus blood flow and coronary vascular resistance and quantification of coronary arterial diameters using a computer-assisted technique were performed before and after each injection of 20, 50 and 100 micrograms of acetylcholine. Significant increase in coronary sinus blood flow and significant decrease in coronary vascular resistance occurred after intracoronary injection of acetylcholine. In contrast, mean diameter of normal epicardial coronary artery tended to decrease and that of irregular epicardial coronary artery decreased significantly after intracoronary injection of acetylcholine. Intracoronary injection of acetylcholine increases coronary blood flow, suggesting vasodilation in the coronary arteriolar bed, while it induces vasoconstriction in most of epicardial coronary arteries in adult humans.

Acetylcholine↗
PubMed1988

Suppression of exercise-induced angina by magnesium sulfate in patients with variant angina.

The effects of intravenous magnesium on exercise-induced angina were examined in 15 patients with variant angina and in 13 patients with stable effort angina and were compared with those of placebo. Symptom-limited bicycle exercise and thallium-201 myocardial scintigraphy were performed after intravenous administration of 0.27 mmol/kg body weight of magnesium sulfate and after placebo on different days. In all patients, serum magnesium levels after administration of magnesium sulfate were about twofold higher than levels after placebo. Exercise-induced angina associated with transient ST segment elevation occurred in 11 patients with variant angina receiving placebo and in only 2 of these patients receiving magnesium (p less than 0.005). On the other hand, exercise-induced angina was not suppressed by magnesium in any patient with stable effort angina. In these patients there was no significant difference in exercise duration after administration of placebo versus after administration of magnesium. The size of the perfusion defect as measured by thallium-201 scintigraphy was significantly less in patients with variant angina receiving magnesium than that in those receiving placebo (p less than 0.001), whereas it was not significantly different in patients with stable effort angina receiving placebo versus magnesium. In conclusion, exercise-induced angina is suppressed by intravenous magnesium in patients with variant angina but not in patients with stable effort angina. This beneficial effect of magnesium in patients with variant angina is most likely due to improvement of regional myocardial blood flow by suppression of coronary artery spasm.

Adult↗
PubMed1988

Deletion of a single chromosome band 4q26 in a malformed girl: exclusion of Rieger syndrome associated gene(s) from the 4q26 segment.

We report a malformed girl with a single chromosome band deletion of 4q26 in peripheral lymphocytes. This patient is the fourth case reported with an interstitial deletion involving 4q26 and has the smallest deletion of those reported. Deletion mapping indicates that psychomotor retardation, coloboma, prominent forehead, epicanthus, broad based nose, and broad, thin upper lip are associated with monosomy 4q26, and that gene(s) associated with Rieger syndrome can be excluded from the 4q26 segment.

Abnormalities, Multiple↗
PubMed1987

Simultaneous multivessel coronary artery spasm demonstrated by quantitative analysis of thallium-201 single photon emission computed tomography.

Thallium-201 myocardial scintigraphy with quantitative analysis of emission computed tomography was performed during episodes of angina in 19 patients with variant angina and nearly normal coronary arteriographic findings. Eleven patients (group I) were shown by arteriography to have spasm in 2 or more large coronary arteries. Eight patients (group II) had spasm in only 1 coronary artery. In 7 patients in group I, significant diffuse perfusion defects simultaneously appeared in multiple coronary artery regions on the scintigram (group IA). The extent and severity of the perfusion defect as measured by thallium-201 tomography were significantly greater in group IA than in group II (p less than 0.001 and p less than 0.01, respectively). The duration of transient ST-segment elevation during the attack in group IA was significantly longer than in group II (p less than 0.001). The incidence of ventricular arrhythmias, including ventricular tachycardia, or complete atrioventricular block during the anginal attack was significantly higher (p less than 0.05) in group IA than in group II. In all study patients, neither attack nor scintigraphic perfusion defect appeared on the repeat test after oral administration of nifedipine. In conclusion, multivessel coronary artery spasm simultaneously appears and causes the attack in many patients with variant angina and nearly normal coronary arteriographic findings, and myocardial ischemia due to simultaneous multivessel coronary spasm is likely to be more extensive and severe, persist longer and have a higher frequency of potentially dangerous arrhythmias than that due to spasm of only 1 coronary artery.

Angina Pectoris, Variant↗
PubMed1987

In vitro effects of prostaglandins on human retinoblastoma cell line, Y-79 cells.

Prostaglandins (PGs) and their derivatives have been reported to modulate or inhibit a variety of tumor cells in vitro and in vivo. In the present study, an established retinoblastoma cell line, Y-79, was investigated for 1) its capacity to synthesize PGs and 2) its susceptibility to PGs and their derivative, 64E, exogenously given. The capacity of Y-79 cells to produce PGs was estimated by thin layer chromatography using [1-14C] arachidonic acid as a substrate, and it was found that no detectable amounts of PGD2, PGE2, PGF2 alpha, thromboxane B2, or 6-keto PGF1 alpha were produced by Y-79 cells. Furthermore, the effects of exogenously given PGs (PGA1, A2, D2, E1, E2, F2 alpha, and J2) and 64E on the cell proliferation of Y-79 cells in culture were examined. PGE1, E2, and F2 alpha showed no significant effects on the cell growth of Y-79 cells at all tested doses (1-20 micrograms/ml). On the other hand, PGA1, A2, D2, and J2, and 64E remarkably inhibited the cell growth of Y-79 cells. A dose-response study indicated that 64E was the most effective among these drugs, followed by PGJ2. PGD2, A1, and A2 were less effective than PGJ2. The present data demonstrate that Y-79 cells do not produce endogenous PGs, and that these cells are highly susceptible to exogenous PGs (PGJ2, D2, A1, and A2) as well as 64E.

Cell Division↗
PubMed1987

In vivo effects of prostaglandins on human retinoblastoma cells in nude mice.

Prostaglandin D2 (PGD2) and 64E, a derivative of PGs, were tested for their capacity to suppress the growth of retinoblastoma in the nude mouse. Ten million cells of an established cell line of human retinoblastoma, Y-79 cells, were transferred subcutaneously into the nude mouse, and after the transferred cells became a tumor with a diameter larger than 7.5 mm, either PGD2 (1, 2, or 4 mg/kg/day) or 64E (4 mg/kg/day) dissolved in Hanks' solution was daily injected subcutaneously near the tumor for 14 days. The estimated tumor weight as defined by the formula of (length) X (width)2/2 was evaluated at various time intervals after the treatment. Although a low dose of PGD2, 1 mg/kg/day, had no effect, higher doses of PGD2 had a clear effect in suppressing the growth of retinoblastoma in the nude mouse. Tumors in 64E-treated animals were also markedly suppressed in their growth. Histological examination revealed that tumors treated with these drugs had a much larger area of necrosis with fewer tumor cells than the tumors in control animals.

Animals↗
PubMed1986

Does 'extended' pelvic lymphadenectomy truly contribute to the management of bladder carcinoma?

During a 3-year period, 41 patients with primary bladder carcinoma were treated with cystectomy along with pelvic lymphadenectomy. Although lymphadenectomy was useful for more accurate staging in patients with T2 or more invasive disease, it contributed little to the surgical curability of the disease, irrespective of extensive nodal dissection in the pelvis. Based on the characteristic lymphatic spread of the disease, limited dissection to the regional nodal area seemed to be satisfactory in the surgical management of bladder carcinoma.

Follow-Up Studies↗
PubMed1986

Bladder tumor occurring in the contracted bladder following urinary tract tuberculosis.

We report a case of bladder squamous cell carcinoma which occurred in the contracted bladder following urinary tract tuberculosis 20 years earlier. The patient came to our hospital complaining of gross hematuria, so we suspected recurrence of urinary tract tuberculosis. We administered rifampicin and ethanbutol. However, urine culture was negative and urine cytology was positive. Following internal urethrotomy, cystoscopy was performed and a bladder tumor was found. Although in this case there was a long time lag between urinary tract tuberculosis and bladder tumor, it was very difficult to make an exact diagnosis. It would have been even more difficult if there had been coexistence of active tuberculosis. We discuss the points of diagnosis and treatment.

Carcinoma, Squamous Cell↗
PubMed1985

Multiple primary malignancies in childhood cancer.

A total of 2,609 cases of childhood cancer (9,012 person-years), among which there were nine cases of second primary malignant neoplasms, were collected from six institutions. The expected number of second primary cancers was 0.88, and the observed/expected (O/E) ratio was 10.22. The estimated incidence of multiple primary cancers in children with primary cancers was 99.9 per 100,000. The tumor registry of Kanagawa Prefecture had 1,317 cases of childhood cancer with 3,326.4 person-years, among which six multiple primary cancer cases were reported. The O/E ratio was 18.4 with 180.3/100,000 person-years at risk in this series. A total of 51 cases of multiple primary cancer, including 20 synchronous cases, were reported by four major registries of childhood cancers. Frequent association with nervous tissue tumors was noted. In 17 cases the second tumor followed retinoblastoma, and most second tumors were related to radiation therapy. In the remaining 14 cases the second tumors varied; hematopoietic neoplasms in seven, thyroid carcinoma in three, and bone and connective tissue tumors in four.

Adolescent↗
PubMed1984

A decreasing tendency for cytogenetic abnormality in peripheral lymphocytes of retinoblastoma patients with 13q14 deletion mosaicism.

A significant decrease in the proportion of 13q14-deleted cells over a 9-month period was observed in a boy with retinoblastoma and 13q14 deletion mosaicism. To evaluate whether this phenomenon is generally the case, the bloods of three retinoblastoma patients with 13q14 deletion mosaicism reported in 1981 and 1982 were reexamined. A significant decrease in the proportion of abnormal cells was observed in three of four patients including the present case, suggesting that a 13q14 deletion mosaicism might disappear with age in some individuals.

Age Factors↗