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Biomedical subjects

S Oishi

Publications and source records attributed to S Oishi.

At least 73 records · Page 4Linked to original sources
PubMed1992

Reproductive and neurobehavioural effects in three-generation toxicity study of piperonyl butoxide administered to mice.

Piperonyl butoxide (PB) was administered continuously to mice from 5 weeks of age in the F0 generation to weaning of the F2 generation. PB was administered in the diet at levels of 0 (control), 0.1, 0.2, 0.4 and 0.8%. Selected reproductive, developmental and behavioural parameters were measured. Litter size and litter weight were reduced in higher-dosed groups, and the body weight of the pups in the lactation period was reduced in dosed pups in each generation. The survival index at postnatal day 21 of the group receiving 0.8% PB was reduced in each generation. The developmental and behavioural parameters in the lactation period were little different from those of the controls, apart from olfactory orientation in the F1 generation. However, in the F2 generation mice, surface righting, cliff avoidance and olfactory orientation were adversely affected in treatment groups. The results suggest that PB had adverse effects on reproductive, developmental and behavioural parameters of mice, with increasing effects in subsequent generations of offspring.

Administration, Oral↗
PubMed1992

Sub-acute toxicity of piperonyl butoxide in F344 rats.

Piperonyl butoxide, alpha-[2-(2-Butoxyethoxy)ethoxy]-4,5-methylenedioxy- 2-propyltoluene, is a pesticide synergist. F344 rats of both sex were maintained on diets containing 0, 0.6, 1.2 or 2.4% of piperonyl butoxide for 13 weeks. At the end of experimental period, they were necropsied. Selected organs were weighted and serum was analyzed by clinical chemistry. In male and female rats of the 2.4%-group, body weight gains were depressed, macroscopically, hepatomegaly was marked and liver weights were significantly higher than those of the control group. In male and female rats of all treated groups, relative kidney weights were significantly increased in a dose-dependent manner. Rats of the 2.4%-group had increased levels of albumin, cholesterol, urea nitrogen and gamma-glutamyl transpeptidase. Examination of livers of the male 2.4%-group by light microscopy showed enlarged hepatocytes with glassy cytoplasm and fatty deposition. On occasion, there was coagulative necrosis of a few hepatocytes in the periportal area and oval cell proliferation. The kidney of treated rats showed atrophy of epithelium in the proximal convoluted tubules. These results indicated that toxicity of piperonyl butoxide in rats was directed primarily to the liver and kidney.

Animals↗
PubMed1992

Altered sympathetic tone in hypertensives with angina and lowered threshold for pacing ischemia.

To determine the role of the sympathetic nervous system in myocardial ischemia with essential hypertension, plasma norepinephrine, heart rate (HR), blood pressure (BP), and the HR.BP double product at the time of silent ischemia during pacing and exercise treadmill test (ETT) were compared with basal values in 20 patients with sustained essential hypertension and stable angina, 3 to 60 days (12.6 +/- 11.6) after discontinuation of all antihypertensive and coronary vasodilator therapy. Group I (N = 6) had silent ischemia with a higher HR.BP product at ETT than at pacing (ratio = 157 +/- 10.4% [+/- SD] v a value in group II [N = 5] of 102 +/- 18.8 [P less than .01]. Group III (N = 9) had no silent ischemia at ETT or pacing. Group I v group II plasma norepinephrine levels at rest and with pacing silent ischemia were 76 +/- 37 v 138 +/- 36 pg/mL, P less than .02, and 101 +/- 50 v 230 +/- 43 pg/mL, P less than .01, respectively. In groups I and II plasma norepinephrine levels were significantly lower than those of group III. Eleven of 20 patients had ischemia on pacing or ETT. Left ventricular myocardial mass were greater (224 +/- 49 v 180 +/- 28 g, p less than .05), HR (67 +/- 13 v 76 +/- 11 beats/min, P = NS) and plasma norepinephrine levels at rest (104 +/- 47 v 241 +/- 99 pg/mL, P less than .01), pacing (160 +/- 81 v 338 +/- 94 pg/mL, P less than .01), and ETT (758 +/- 268 v 1203 +/- 611 pg/mL, P less than .05), were lower in patients with ischemia (N = 11, group II) than in patients without ischemia (N = 9, group III) on pacing or ETT. Eight patients were on reserpine prestudy; reserpine prestudy was associated with lower basal HR (63 +/- 9 v 76 +/- 12 beats/min, P less than .05) and plasma norepinephrine (106 +/- 48 v 169 +/- pg/mL, P less than .07) and greater ratio of HR.BP double product on ETT/pacing, (141 +/- 33 v 111 +/- 19, P less than .02). The sympathetic nervous tone of group I was low at baseline but there may have been raised alpha/beta-receptor responsiveness to laboratory stresses with concomitant micro/macrovascular constriction at higher oxygen demand.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1992

Calcitonin release from medullary thyroid carcinoma by thyrotropin-releasing hormone: comparison with calcium injection.

The effects of thyrotropin-releasing hormone on the release of calcitonin were investigated in 15 normal subjects and 12 patients with medullary thyroid carcinoma. The present study also compared the effect of TRH stimulation with calcium infusion test on calcitonin release in patients with medullary thyroid carcinoma. In normal subjects, calcitonin increased from a basal value of 7.5 +/- 2.5 pmol/l to a peak value of 9.4 +/- 3.0 pmol/l (p less than 0.01) after iv injection of synthetic TRH (500 micrograms). Basal calcitonin values in patients with medullary thyroid carcinoma were high (1216 +/- 2230 pmol/l, p less than 0.05), and TRH induced a further increase in calcitonin to 1842 +/- 3149 pmol/l in all the patients (p less than 0.05). They had a peak value of 7891 +/- 13,528 pmol/l after the calcium infusion, which was significantly higher than the basal value of 1463 +/- 2630 pmol/l (p less than 0.05). All medullary thyroid carcinoma patients displayed a marked calcitonin increase after TRH and calcium stimulation. Although the increase in serum calcitonin after TRH injection was lower than that after calcium injection (1.6-fold vs 5.4-fold, p less than 0.05), there was no significant difference in mean peak calcitonin value following TRH and calcium injection in patients with medullary thyroid carcinoma. These results indicated that TRH could stimulate calcitonin release from the thyroid C-cells in both normal subjects and patients with medullary thyroid carcinoma.

Adult↗
PubMed1991

Application of schlieren optics to real-time monitoring of protein electrophoresis in crosslinker-free linear polyacrylamide solution.

Molecular sieving effect of crosslinker-free linear polyacrylamide solutions could be visualized in a real-time mode using schlieren optics for electrophoresis of proteins. Since linear polymer solutions are going to find application in capillary electrophoresis (Zhu, M., et al., J. Chromatogr. 1989, 480, 311-319), the above approach may be useful for obtaining basic data of electrophoresis of proteins and nucleic acids in such media under conditions free from the predominant wall effect pertinent to the use of a capillary.

Cross-Linking Reagents↗
PubMed1991

Comparison of labetalol versus enalapril as monotherapy in elderly patients with hypertension: results of 24-hour ambulatory blood pressure monitoring.

PURPOSE: This study compared the safety and efficacy of labetalol and enalapril as antihypertensive therapy for elderly patients. PATIENTS AND METHODS: A randomized, open-label, parallel controlled trial was conducted. After completing a 4-week placebo phase, 79 elderly (65 years or older) patients with an average standing diastolic blood pressure (BP) 95 mm Hg or above and 114 mm Hg or less were randomized to receive a 12-week course of either labetalol or enalapril in an open-label design. The patients' BP and heart rate were evaluated biweekly by trained observers unaware of the treatment status, and drug dosage was titrated (up to 400 mg twice a day of labetalol or 40 mg daily of enalapril) to achieve a standing diastolic BP of less than 90 mm Hg and a decrease of 10 mm Hg from baseline. Patients underwent 24-hour ambulatory BP monitoring (ABPM) at the end of the placebo phase and again after 8 weeks of active treatment. RESULTS: The treatment groups were comparable in their reduction of supine diastolic BP, with no significant differences between the two treatments. Labetalol demonstrated a significantly greater reduction (p less than 0.05) in standing diastolic BP at the end of the titration period compared to enalapril, but this difference was not significant by the end of the study period. Based on 24-hour ABPM readings, labetalol reduced mean 24-hour diastolic BP (p less than 0.05) and mean heart rate (p less than 0.05) more than enalapril. The labetalol-treated patients were significantly less often above their diastolic BP goal throughout the 24-hour ABPM period (p less than 0.01). The two treatments were equally well tolerated. CONCLUSIONS: The results indicate that labetalol and enalapril are equally effective in lowering supine diastolic BP in the elderly, but labetalol is more effective in lowering ambulatory BP and heart rate throughout the day.

Aged↗
PubMed1990

Effects of phthalic acid esters on testicular mitochondrial functions in the rat.

Although it is well established that high dose administration of di(2-ethylhexyl) phthalate (DEHP) and its monoester metabolite (MEHP) induces severe testicular atrophy in rats, the mechanisms of this testicular injury is not clear. The present experiment was undertaken to examine the effects of DEHP and MEHP on mitochondrial functions of rat testis. DEHP and di-n-octyl phthalate (DOP), a DEHP isomer which causes less severe testicular injury, did not inhibit the state 3 oxygen consumption up to 0.65 mumole/ml in vitro. On the other hand, MEHP and mono-n-octyl phthalate (MOP), a metabolite of DOP, inhibited the state 3 oxygen consumption down to a concentration of 0.065 mumole/ml. Testicular mitochondrial respiratory functions of rats administered 2 g/kg DEHP were lower than those of control or DOP-treated rats. These differences were verified by characteristics of pharmacokinetic parameters and testicular concentrations of MEHP and MOP. It may be suggested that a possible mechanism of testicular atrophy induced by DEHP may be due to direct inhibition by MEHP (and partially DEHP) of the respiratory functions of Sertoli cell mitochondria in rat testis.

Animals↗
PubMed1990

Rheumatoid factor modulation of neutrophil superoxide generation enhancing activity of preformed immune complexes.

Heat aggregated human (HAG) IgG pretreated with total rheumatoid factors isolated from the serum of rheumatoid arthritis patients showed decreased superoxide generation enhancing activity as compared with HAG pretreated with buffer alone. Similarly, monoclonal IgM rheumatoid factor isolated from the serum of a patient with macroglobulinemia complicated by rheumatoid arthritis inhibited superoxide generation enhancing activity of HAG. On the other hand, superoxide generation enhancing activity of BSA-antiBSA immune complexes was not affected by preincubation with rheumatoid factors isolated from the sera of either rheumatoid arthritis patients or the macroglobulinemia patient. Rheumatoid factors isolated from rheumatoid arthritis serum were fractionated by high performance liquid chromatography and IgM-class and IgG-class rheumatoid factors were obtained. IgG-class rheumatoid factor significantly enhanced the superoxide generation enhancing activity of HAG, whereas IgM rheumatoid factor inhibited it. Rheumatoid arthritis sera showed significantly higher superoxide generation enhancing activity than normal sera. HAG preincubated with rheumatoid arthritis sera showed significantly lower superoxide generation enhancing activity than HAG preincubated with normal sera. These results suggest that factors inhibiting superoxide generation enhancing activity of HAG are present in rheumatoid arthritis sera, and that the responsible is IgM rheumatoid factor, whereas IgG rheumatoid factor enhances it. The factors that express superoxide generation enhancing activity in rheumatoid arthritis sera are suggested to be intermediate size immune complexes.

Antigen-Antibody Complex↗
PubMed1990

Isolation and characterization of the minor components associated with microcystins LR and RR in the cyanobacterium (blue-green algae).

Two structurally similar analogues of microcystins LR and RR, cyclic peptide hepatotoxins from Microcystis, were isolated by chromatographic methods. Although they have the same mol. wt and amino acid compositions as those of the parent toxins, they do not possess similar toxicities. Ultraviolet and 1H-NMR spectral data for both components demonstrate clear structural difference of these cyclic peptides from the parent toxins, which are probably responsible for the marked decreases in their observed toxicities.

Amino Acids↗
PubMed1990

Analysis of eight Sipple's syndrome patients and review of eighty-two cases from the Japanese literature.

Eight Sipple's syndrome patients from four families have been reviewed. One family had the largest number of members with pheochromocytoma and/or medullary thyroid carcinoma. A total of 82 cases (47 females and 35 males) collected from the Japanese literature during the period 1960-1989, are also reviewed. The ages ranged from 22 to 73 (median 41) years, 13%, being over the age of 60 years (elderly patients). Pheochromocytoma occurred bilaterally in 72% of cases. With Sipple's syndrome, a relatively high urinary excretion of the epinephrine fraction and a high content of epinephrine in the tumor tissues were thought to be characteristic. Seventy-three patients underwent adrenalectomy with a successful outcome for 62 (85%). There needs to be careful periodic follow-up after unilateral adrenalectomy. Medullary thyroid carcinoma (MTC) also occurred bilaterally and was multicentric in 66% of cases, and was often found to be metastasized to the cervical lymph nodes at the time of surgery (35%). Parathyroid disease was found in 22% of cases: parathyroid adenoma in nine, hyperplasia in 10. Fourteen patients (17%) died of surgical complications, hypertensive crisis caused by excessive catecholamine release and/or widespread MTC metastases.

Adrenal Gland Neoplasms↗
PubMed1989

Effects of co-administration of di(2-ethylhexyl)phthalate and testosterone on several parameters in the testis and pharmacokinetics of its mono-de-esterified metabolite.

The administration of 1 g/kg di(2-ethylhexyl)phthalate (DEHP) or 5 mg/kg testosterone for 1 week did not affect the testicular and prostatic gland weights in rats. However, co-administration of DEHP and testosterone induced severe testicular atrophy accompanied by a decrease of zinc concentration in the testis and reduction of the activity of testicular specific lactate dehydrogenase isozyme. These changes were similar to the results of high dose administration of DEHP alone. Values of biological half-life and area under the concentration-time curve (AUC) of mono(2-ethylhexyl)phthalate, the main metabolite of DEHP, in testes after a single co-administration of DEHP (p.o.) and testosterone (i.p.) were higher than those after DEHP administration alone. Results suggest that the co-administration of DEHP and testosterone enhanced the adverse effects of DEHP on testes as the result of changes in pharmacokinetic values of MEHP.

Animals↗
PubMed1989

Enhancing effects of luteinizing hormone-releasing hormone on testicular damage induced by di-(2-ethylhexyl)phthalate in rats.

The administration of 1.5 g/kg of di-(2-ethylhexyl)phthalate (DEHP), 50 or 10 micrograms/kg of luteinizing hormone-releasing hormone (LRH) to male Crj:Wistar rats for 1 week did not affect their testicular and prostatic gland weights. Co-administration of DEHP and LRH, however, induced testicular atrophy coincident with decreases in zinc and sulfhydryl concentration in the testis and reduction of the activity of testicular specific lactate dehydrogenase isozyme. These changes were similar to the results of high-dose administration of DEHP alone. Liver enlargement and hypolipidemia (reduction of serum cholesterol, triglycerides and phospholipids) occurred sometimes after co-administration of DEHP and LRH.

Animals↗
PubMed1989

Pheochromocytoma associated with Behçet's disease.

A 32-yr-old man was admitted to our clinic complaining chiefly of paroxysmal attacks of headaches and palpitations. He had had intermittent episodes of joint pains, erythema nodosum-like eruptions of the lower limbs, oral aphtha, and a fever lasting for three years. Ultrasonography, computerized tomography and magnetic resonance imaging scanning showed a mass in the left adrenal gland. A diagnosis of pheochromocytoma was made from the elevated plasma and urinary catecholamines and abnormal uptake of 131I-metaiodobenzylguanidine. The tumor was successfully removed, and the patient's plasma and urinary catecholamine levels returned to within the normal range. High fever, aphtha of the mouth, erythema of the lower extremities and genital ulcers were, however, frequently observed. A diagnosis of Behçet's disease was then established. The association of the pheochromocytoma with Behçet's disease was thought to be a chance one: to our knowlege, this has been the first case of a pheochromocytoma associated with Behçet's disease.

Adrenal Gland Neoplasms↗
PubMed1988

Analysis and purification of toxic peptides from cyanobacteria by reversed-phase high-performance liquid chromatography.

A simple, rapid and reliable chemical analysis method for microcystins (cyanoginosins) has been studied. Three different mobile phases for high-performance liquid chromatography were selected and optimized. Also the adsorptive powers of three commercially available C18 cartridges were compared and the results successfully applied to the clean up of three of the toxins. Finally a total system for the analysis and isolation of microcystins was established.

Chromatography, High Pressure Liquid↗
PubMed1988

Elevated serum neuron-specific enolase in patients with malignant pheochromocytoma.

Neuron-specific enolase (NSE), an isomer of glycolytic enzyme enolase, is found exclusively in neuroendocrine cells and in neuroendocrine tumors in a considerably large quantity. Circulating levels of serum NSE were measured by radioimmunoassay in 24 normal adults, 23 patients with benign pheochromocytoma, three patients with malignant pheochromocytoma, and seven patients with medullary thyroid carcinoma. The mean serum NSE in normal adults was 5.8 +/- 1.3 ng/ml (mean +/- standard deviation [SD], and the range was 3.8 to 8.9 ng/ml). It also was normal in patients with benign pheochromocytoma (5.7 +/- 1.8 ng/ml; range, 2.2 to 9.3 ng/ml). However, serum NSE was elevated significantly (17.2 +/- 7.2 ng/ml; range, 10.4 to 27.3 ng/ml) in all three patients with malignant pheochromocytoma (P less than 0.01). In patients with medullary thyroid carcinoma the serum NSE remained within normal limits (5.5 +/- 1.7 ng/ml; range, 3.9 to 8.2 ng/ml). These results suggest that serum NSE might be a useful marker for screening of malignant pheochromocytoma.

Adrenal Gland Neoplasms↗