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Biomedical subjects

Y Maeda

Publications and source records attributed to Y Maeda.

At least 811 records · Page 45Linked to original sources
PubMed1989

Anabolic steroid-associated hypogonadism in male hemodialysis patients.

Hypogonadism in male hemodialysis patients has been previously reported. However, its precise pathogenesis has not yet been clarified. Mepitiostane and nandrolone decanoate are anabolic steroids prescribed for uremic anemia, and those may possibly exacerbate uremic gonadal damage. We studied the influences of these steroids on male gonadal function. Seventy-six hemodialysis patients were selected and examined for levels of luteinizing hormone (LH), follicular stimulating hormone (FSH), total testosterone, and prolactin. Twenty-three patients who received anabolic steroids showed lower testosterone values (205.2 +/- 35.6 ng/dl) than did patients without these steroids (449.7 +/- 21.3 ng/dl). Gonadotropins and prolactin showed no significant differences between the patients with and without the steroids. The testosterone values of three patients with mepitiostane increased after they stopped taking steroids. One patient suffering from complete aspermia recovered (sperm count: 0/ml to 1300 x 10(4)/ml) after discontinuation of mepitiostane and administration of human chorionic gonadotropin (HCG). This clinical study suggests that some anabolic steroids play a role in uremic hypogonadism; thus mepitiostane or its analogues should be carefully prescribed for young male patients.

Adult↗
PubMed1989

X-radiation-induced differentiation of xenotransplanted human undifferentiated rhabdomyosarcoma.

A serially xenotransplantable strain of undifferentiated embryonal rhabdomyosarcoma originating from the nasal cavity of a 42-year-old woman has been established in our laboratory. After radiotherapy for the tumor donor, distinct rhabdomyoblastic differentiation of the undifferentiated sarcoma cells appeared in the primary lesion, and it is a reasonable assumption that X-irradiation has a certain potentiality to induce morphologic differentiation of tumor cells. To study this possibility, tissue fragments of undifferentiated embryonal rhabdomyosarcoma that had grown to more than 10 mm after being transplanted to nude mice were selectively irradiated in situ. The degree of rhabdomyoblastic differentiation according to radiation dose was evaluated by light and electron microscopy and by immunostainability for myoglobin, creatine phosphokinase-MM, and desmin. Distinct morphologic differentiation of undifferentiated sarcoma cells could be induced by repeated X-irradiations at several-week intervals.

Adult↗
PubMed1988

Hair protein glycation as a long-term index of blood glucose in diabetics.

We used furosine, which is derived from fructose-lysine and is a glycation product, to measure the extent of hair protein glycation in diabetic patients. We took hair samples that were 12 cm long, corresponding roughly to 1 year's growth. While the furosine levels in these samples correlated poorly with fasting plasma glucose (FPG) and with hemoglobin A1c (HbA1c) levels at the time of sampling, better correlations were observed between glycation and the year-long average values of FPG, HbA1c, and the conduction velocities in two peripheral nerves. The glycation levels in these samples may thus reflect the year-long average of the patient's blood glucose. Hair glycation may serve as a valuable indicator both of long-term blood glucose trends and of the relationship between diabetic complications and blood glucose.

Adult↗
PubMed1988

Regulation of Fc epsilon R2/CD23 gene expression by cytokines and specific ligands (IgE and anti-Fc epsilon R2 monoclonal antibody). Variable regulation depending on the cell types.

The regulation of human low affinity FcR for IgE (Fc epsilon R2/CD23) and the soluble Fc epsilon R2 [IgE binding factor (BF)] of monocyte (U937), T (ED), and B (JIJOYE) cell lines was examined by anti-Fc epsilon R2 mAb (H107, Mab176) and the cDNA probe for Fc epsilon R2. The effect of IL-4 and IFN-gamma on Fc epsilon R2 regulation was variable among these three cell lines. IL-4 and IFN-gamma enhanced the Fc epsilon R2 gene expression and the production of Fc epsilon R2 and IgE-BF on U937, whereas IL-4 and IFN-gamma had no significant effect on the Fc epsilon R2 expression on ED. On JIJOYE, IL-4 enhanced the Fc epsilon R2 and IgE-BF production on both protein and mRNA levels. In U937 and JIJOYE cells, there was a marked increase of Fc epsilon R2 mRNA after combined stimulation with IFN-gamma and IL-4. However, in JIJOYE cells, there was a dissociation between the surface expression of Fc epsilon R2 and Fc epsilon R2 mRNA treated with IFN-gamma plus IL-4. In these cells. IFN-gamma even down-regulated the IL-4-induced expression of surface Fc epsilon R2. Stimulation of JIJOYE cells with both IFN-gamma and IL-4 resulted in the increase of the IgE-BF in the supernatant, suggesting that IFN-gamma enhanced the release of IgE-BF from Fc epsilon R2. The results indicated that Fc epsilon R2 and IgE-BF expression is regulated by IFN-gamma at least on two different levels: on transcriptional levels and the levels of cleavage of the surface Fc epsilon R2 to release soluble Fc epsilon R2 (IgE-BF). Ligands binding to the Fc epsilon R2 such as IgE and anti-Fc epsilon R2 mAb enhanced the surface expression of Fc epsilon R2 on these Fc epsilon R2(+) cell lines. This was mainly due to the surface accumulation of the receptors on JIJOYE and U937. However, the stimulation of ED by H107 and anti-Fc epsilon R2 mAb significantly enhanced the mRNA expression, indicating that Fc epsilon R2 synthesis may also be up-regulated by the specific ligands in some cell types.

Antibodies, Monoclonal↗
PubMed1988

The oriC unwinding by dam methylation in Escherichia coli.

It has been shown that dam methylation is important in the regulation of initiation of DNA replication in E.coli. The question then arises as to whether dam methylation in the oriC region mediates any structural changes in DNA involved in the regulation of initiation of DNA replication. We demonstrate that the thermal melting temperature of the oriC region is lowered by adenine methylation at GATC sites. The regulation of initiation of DNA replication by dam methylation may be attributed to the ease of unwinding at GATC sites in oriC.

Adenine↗
PubMed1988

Coordinates transformation and learning control for visually-guided voluntary movement with iteration: a Newton-like method in a function space.

In order to control visually-guided voluntary movements, the central nervous system (CNS) must solve the following three computational problems at different levels: (1) determination of a desired trajectory in the visual coordinates, (2) transformation of the coordinates of the desired trajectory to the body coordinates and (3) generation of motor command. In this paper, the second and the third problems are treated at computational, representational and hardware levels of Marr. We first study the problems at the computational level, and then propose an iterative learning scheme as a possible algorithm. This is a trial and error type learning such as repetitive training of golf swing. The amount of motor command needed to coordinate activities of many muscles is not determined at once, but in a step-wise, trial and error fashion in the course of a set of repetitions. Actually, the motor command in the (n + 1)-th iteration is a sum of the motor command in the n-th iteration plus two modification terms which are, respectively, proportional to acceleration and speed errors between the desired trajectory and the realized trajectory in the n-th iteration. We mathematically formulate this iterative learning control as a Newton-like method in functional spaces and prove its convergence under appropriate mathematical conditions with use of dynamical system theory and functional analysis. Computer simulations of this iterative learning control of a robotic manipulator in the body or visual coordinates are shown. Finally, we propose that areas 2, 5, and 7 of the sensory association cortex are possible sites of this learning control. Further we propose neural network model which acquires transformation matrices from acceleration or velocity to motor command, which are used in these schemes.

Central Nervous System↗
PubMed1988

TRH test and DST in schizoaffective mania, mania, and schizophrenia.

The thyrotropin-releasing hormone (TRH) test and the Dexamethasone Suppression Test (DST) were given to 10 patients who met Research Diagnostic Criteria (RDC) for schizoaffective disorder, manic type, 9 who met the criteria for mania, and 27 who met the criteria for schizophrenia. A blunted thyrotropin (TSH) response to TRH was observed in 3 of the 10 schizoaffective manics, 4 of the 9 manics, and 3 of the 27 schizophrenics. Nonsuppression on the DST was observed in 5 of the 10 schizoaffective manics, 2 of the 9 manics, and 2 of 22 schizophrenics. The schizoaffective manic and the manic patients had similar rates of TSH blunting and DST nonsuppression, and these were significantly higher than the rates in the schizophrenic patients. This difference was not attributable to baseline TSH and cortisol levels or to neuroleptic treatment. It is suggested that patients with RDC schizoaffective mania and mania have more disturbance in the hypothalamic-pituitary adrenal and thyroid axes than patients with schizophrenia.

Antipsychotic Agents↗
PubMed1988

Retinyl and 3-dehydroretinyl esters in the crayfish retina.

We have studied chemical nature and localization of retinyl esters stored in the retina of the crayfish, Procambarus clarkii, which has a rhodopsin-porphyropsin visual pigment system. The crayfish kept at 10 degrees C in the constant dark had 3-dehydroretinal along with retinal in the retina as the chromophore of visual pigment. Both retinyl and 3-dehydroretinyl esters were found in the retina, more than 95% of them in the 11-cis configuration. Of three kinds of fatty acid detected in the esters, the major component (about 80%) was the polyunsaturated fatty acid, docosahexaenoic acid (C22 = 6). Observations with electron and fluorescence microscopy and the results of fractionation experiments showed that the esters were stored in photoreceptor cells as oil droplets. The ratio of 3-dehydroretinal/retinal as visual pigment chromophore was always higher than that of 3-dehydroretinol/retinol in the stored esters. This result suggests a mechanism of selective utilization of 3-dehydroretinol for the chromophore of visual pigment in the crayfish retina.

Animals↗
PubMed1988

Hepatocellular carcinoma among HBsAg positive blood donors in Fukuoka, Japan.

In order to examine the association between hepatitis B virus carriage and hepatocellular carcinoma, 3765 HBsAg positive blood donors were followed from 1977 to 1983 in Fukuoka, Japan. The observed number of deaths was compared with the expected deaths calculated by applying cause-, sex- and age-specific death rates for Fukuoka in 1980 to sex- and age-specific population at risk of the subjects. Among 2595 male blood donors, mortality from liver cancer (or hepatocellular carcinoma) was specifically elevated compared with the general population, where the observed, expected deaths and O/E were 15, 2.07 and 7.25, respectively (P less than 0.001). This relative risk was assumed to be underestimated partly because of a healthy donor effect. Neither the HBsAg titer nor the HBeAg-Ab system was related to the risk. Relative risk and population attributable risk % in Japan and various countries were estimated.

Blood Donors↗
PubMed1988

Glycation of cataractous lens in non-diabetic senile subjects and in diabetic patients.

Early- and advanced-stage products in the Maillard reaction, glycation, were measured in patients with diabetic or senile cataracts. Early-stage products were measured by means of furosine, which is an acid-hydrolysis product derived from fructose-lysine. Advanced-stage products were measured by fluorometry using high-performance liquid chromatography. Furosine levels were high (listed in descending order) in capsule, cortex and nucleus in both diabetic and senile cataracts. The advanced-stage products were also high (listed in descending order) in nucleus, cortex and capsule in both diabetic and senile cataracts. These results suggest that advanced-stage products might accumulate in larger amounts in the nucleus and cortex than in the capsule, resulting in the formation of cataracts. The study also revealed that the Maillard reaction plays an important role in causing not only diabetic cataracts but also senile cataracts.

Aged↗
PubMed1988

Child-parent relationships in the care of epileptic children.

We investigated the attitudes of parents toward their epileptic children with the "Taken" diagnostic test for child-parent relationships. Included were 70 epileptic children, 31 boys and 39 girls, and their parents, 16 fathers and 59 mothers. Patients were divided into group A, 35 children without neurologic complications other than seizures, and group B, 35 children with complications. The results were evaluated by comparing with the normal standard revised by Akasaka et al. The parents of group A and the fathers of group B showed rejection toward their children. The mothers of group B showed attitudes of dotage and anxiety, especially when their children were over 12 years of age and the seizures were not controlled. Our observations suggest that mental health care for the parents of epileptic children is necessary to decrease the psychological conflicts and to prevent untoward effects on their offspring.

Adolescent↗