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Biomedical subjects

Y Maeda

Publications and source records attributed to Y Maeda.

At least 865 records · Page 48Linked to original sources
PubMed1987

Thyrotropin, prolactin, and growth hormone responses to thyrotropin-releasing hormone in anorexia nervosa and bulimia.

Serum thyrotropin (TSH), prolactin (PRL), and growth hormone (GH) levels were measured before and after stimulation with thyrotropin-releasing hormone (TRH) in 10 patients with bulimia, 7 with features of the restricting subtype of anorexia nervosa, and 6 with bulimic subtype of anorexia nervosa. The mean basal levels of TSH, PRL, and GH did not differ among the three groups. A delayed TSH response was found in 86% of the restricting anorectics, 80% of the bulimic anorectics, and 22% of the bulimics. The PRL response was normal in all patients, with no significant difference among the three groups. Elevated basal GH levels were found in 29% of the restricting anorectics, 33% of the bulimic anorectics, and 33% of the bulimics. An abnormal GH increase after TRH stimulation was observed in 50% of the restricting anorectics, 20% of the bulimic anorectics, and 13% of the bulimics. These results suggest that some patients with bulimia, and some with anorexia nervosa, have a hypothalamic dysfunction. These neuroendocrine abnormalities do not appear to be due solely to low weight or to metabolic changes resulting from binge eating and are not associated with depressive symptoms.

Anorexia Nervosa↗
PubMed1987

The developmental fate of Dictyostelium discoideum cells depends greatly on the cell-cycle position at the onset of starvation.

The relationship between the development of Dictyostelium discoideum Ax-2 and the cell cycle at the onset of starvation was analysed with special reference to sorting behaviors during the formation of polarized cell masses (slugs), using a method for inducing good synchrony. Cells starved at different cell-cycle positions showed different developmental features during further culture. For example, cells just before mitosis and dividing cells were sorted out into the anterior prestalk zone of migrating slugs, while cells starved during most of the G2-phase, into the posterior prespore zone. Time courses of cell aggregation and tip formation were also found to vary greatly in a cell-cycle-related manner, and cells starved during the late G2-phase showed the most rapid development. Differential chemotaxis and cohesiveness are generally considered to be important for cell sorting in Dictyostelium development. In fact, remarkable differences in the chemotactic ability to a chemoattractant, cAMP, were detected among cells starved at any particular phase of the cell cycle. EDTA-resistant cohesiveness was also acquired differently depending on the cell cycle, and it was stronger in the cells showing more rapid aggregation. These findings indicate a close relation of the cell cycle to the cell sorting and pattern formation. The possible significance of the cell-cycle-related events presented here is discussed, with special emphasis on the process of cell aggregation.

Cell Adhesion↗
PubMed1987

Accelerated glycation of the aorta in diabetic rats.

Glycation of the aorta in rats with streptozotocin-induced diabetes was estimated by determining the early-stage product and the advanced product of the Maillard reaction. The early-stage product of the Maillard reaction was determined using furosine, which is derived from glycated lysine residues by acid hydrolysis. The advanced product was determined by fluorescence high-performance liquid chromatography. The levels of both early-stage and advanced products in diabetic rats were significantly higher than those in non-diabetic rats at the age of both 20 and 50 weeks. The levels of both early-stage and advanced products at 50 weeks in rats tended to be higher than those at 20 weeks. However, the level of glycated hemoglobin in both non-diabetic and diabetic rats showed no significant change between 20 and 50 weeks of age. These results suggest that tissue glycation may be involved in the development of diabetic complications and may be related to the aging mechanism.

Animals↗
PubMed1987

Clinico-pathologic studies on post-operative maxillary cysts.

Microscopic and clinical observations on 70 post-operative maxillary cysts were performed. Cysts of 47 cases were lined with the ciliatal epithelium, and 12 cases were composed of both squamous and ciliated cells. Squamous only and cuboidal lining were found in 9 and 2 cases, respectively. Duration after the antrum operation and the non-vital tooth related to the cyst did not affect the epithelial type, though many of the cases of squamous epithelium possessed infectious histories. From the results, the squamous change seemed to be accelerated by inflammatory irritations, and mucous cells in the lining epithelium were depleted as a part of the metaplastic sequence.

Epithelium↗
PubMed1987

Clinical features of intractable epilepsy in Japanese children.

The clinical features of refractory epilepsy were studied in comparison between 135 patients in a refractory group and 103 in a controlled group. All the children were Japanese. The clinical features of the refractory group were the onset of epilepsy during the first year of life, absence of family history, retarded development before the onset, phakomatoses, daily or weekly seizures, secondarily generalized epilepsy, and marked EEG abnormalities at the initial visit, a change of types in epilepsy, no improvement in EEG findings, mental deterioration or severe retardation during the follow-up. The number of drugs was increased and relatively new drugs such as carbamazepine, valproic acid or clonazepam were frequently administered. The side effects, including gum hypertrophy, drowsiness, hypertrichosis, ataxia or increased serum-GTP, were more frequent in the refractory group.

Age Factors↗
PubMed1987

Effects of estrogen and vanadate on the proliferation of newly established transformed mouse Leydig cell line in vitro.

A permanent cell line (B-1-A-2) derived from an estrogen-responsive mouse Leydig cell tumor (T 124958-R) was established in culture. Although this cell line showed estrogen-induced enhancement of cell proliferation in vitro, a moderately high concentration (10(-8) M) of estradiol was required to stimulate maximum growth. A whole cell binding assay revealed that the B-1-A-2 cells contained estrogen receptors with relatively low affinity for estradiol (Kd, 10(-9)-10(-8) M). This estrogen receptor was found to have a mol wt of 65,000. In addition, incubation of the cells with [32P]orthophosphate and subsequent purification revealed that the estrogen receptor is phosphorylated. This finding prompted us to study the effect of phosphatase inhibitors on cell proliferation. The inclusion of vanadate (25 microM) in the culture medium resulted in a significant increase in estrogen sensitivity, showing a maximal growth stimulatory effect of estradiol at concentrations of 10(-10)-10(-9) M. Simultaneously, the conversion of the low affinity to the high affinity receptor (Kd, 10(-10)-10(-9) M) was induced by treatment of cells with vanadate. These data suggest that estrogen directly stimulates the growth of B-1-A-2 cells in culture, and that the sensitivity to estrogen can be altered by modulating the estrogen receptor possibly via a phosphorylation-dephosphorylation mechanism.

Animals↗
PubMed1987

Suppression of ventricular premature contractions possibly related to triggered activity by oral diltiazem and atenolol.

The clinical importance of triggered activity as a cause of arrhythmias is uncertain. We assumed that ventricular premature contractions (VPCs) caused by triggered activity could be increased at higher heart rates and be suppressed by calcium channel blockers and beta-adrenoceptor blocker. Thus, we evaluated VPC frequency as a function of underlying heart rate and examined the efficacy of diltiazem and atenolol on VPCs, using 24 hour ECG recording. Plots of VPC frequency vs. heart rate were made at 1-beat/min intervals for all heart rates recorded for at least 5 min during 24 hours. Diltiazem (90-180 mg/day) and atenolol (50 mg/day) were given orally for 4 weeks, respectively in 36 and 16 patients with VPCs of more than 2000/day. Patterns of relationship between VPC frequency and heart rate observed before diltiazem therapy included: an increase of VPCs at higher heart rates (positive correlation) in 16 patients, an increase at low heart rates and a decrease at high heart rates (bidirectional correlation) in 13 patients, an increase at low heart rates and flat curve at high heart rates (positive-flat correlation) in 5 patients, a linear decrease (negative correlation) in 1 patient, and flat curve (flat correlation) in 1 patient. The patterns of correlation in patients treated with atenolol were positive in 6, bidirectional in 7, positive-flat in 2 and negative in 1. Both drugs significantly reduced the VPC frequency per 24 hours for patients with a positive correlation (P group), but induced no significant change for those with the other patterns of correlation (NP group). At the 70% VPC suppression level, diltiazem was effective in 9 of 16 patients of P group and only 1 of 20 patients of NP group (p less than 0.01); atenolol was effective in 5 of 6 patients of P group and only 1 of 10 patients of NP group (p less than 0.05). Both drugs reduced the slope of a positive correlation. These results suggest that: VPCs which increase at higher heart rates may be related to triggered activity, and an evaluation of VPC frequency as a function of heart rate predicts the response of VPCs to diltiazem and atenolol, and probably to other calcium antagonists and beta blockers.

Administration, Oral↗
PubMed1987

High-performance liquid chromatographic method for the analysis of N tau-methylhistidine in food, chicken excreta, and rat urine.

A reliable high-performance liquid chromatographic method that utilizes a reversed-phase separation with ion-pairing and post-column fluorescence derivatization for the analysis of N tau-methylhistidine in food, chicken excreta, and rat urine is described. N tau-Methylhistidine in the hydrolyzed sample is first roughly separated from acid and neutral amino acids by an ion-exchange column. The N tau-methylhistidine fraction is then evaporated and the residue is dissolved in the mobile phase (15 mM sodium octane sulfonate in 20 mM potassium phosphate), and subjected to high-performance liquid chromatography.

Animal Feed↗
PubMed1987

Fractional rates of muscle protein synthesis and degradation in chickens with genetic muscular dystrophy.

Rates of synthesis (ks) and degradation (Kd) of muscle protein of normal (+/+) and muscular dystrophic (am/am) chicks of the GNS/2 strain obtained from a Fayoumi population were estimated based on the urinary excretion of N tau-methylhistidine. Both fractional rates of muscle protein synthesis and degradation of the line with muscular dystrophy at 4 and 20 weeks of age were greater than that of normal chicks. The muscular dystrophy gene affected the increase in rate of degradation more than the increase in fractional rate of synthesis.

Animals↗
PubMed1987

Hepatocellular carcinoma among female Japanese hepatitis B virus carriers.

In order to examine the association between hepatitis B virus carriage and hepatocellular carcinoma 3,769 female hepatitis B surface antigen positive blood donors were followed-up from 1977 to 1985 in Fukuoka, Japan. The observed number of deaths was compared with the expected deaths calculated by applying cause- and age-specific death rates among females for Fukuoka in 1980 to age-specific population at risk of the subjects. Mortalities from all causes and from all malignant neoplasms were decreased. Mortality from liver cancer (or hepatocellular carcinoma) was specifically elevated as compared with the general population; where observed, expected deaths, and O/E were 4, 0.71, and 5.63, respectively (p less than 0.05). Population attributable risk was estimated to be 6.5%. These values were assumed to be somewhat underestimated, in part because of a healthy donor effect and limited observation period.

Adult↗