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Biomedical subjects

M Uchiyama

Publications and source records attributed to M Uchiyama.

At least 181 records · Page 10Linked to original sources
PubMed1998

Effects of homologous natriuretic peptides in isolated skin of the bullfrog, Rana catesbeiana.

The effects of frog atrial (fANP), brain (fBNP) and C-type natriuretic peptide (fCNP) on transepithelial ion transport were investigated in the bullfrog, Rana catesbeiana. The transepithelial potential difference (PD) and short-circuit current (Isc) of the abdominal skin were measured according to the technique of Ussing and Zerahn. When the abdominal skin was exposed to homologous natriuretic peptides (NPs) at concentrations ranging from 4 x 10(-13) to 5 x 10(-7) M, no significant changes in PD or Isc were observed. The influence of the NPs on the arginine vasotocin (AVT)-induced increase in Isc was then examined. Treatments with ANP and BNP (4 x 10(-9)-4 x 10(-8) M) inhibited the increase in the AVT (10(-8) M)-induced Isc. Furthermore, fCNP I and fCNP II (5 x 10(-13)-5 x 10(-7) M) did not significantly inhibit the increase in the AVT-induced Isc. The cyclic GMP analog, 8-BrcGMP, (> 10(-4) M) with AVT inhibited the increase of AVT-induced ISc, as well as fANP and fBNP. HS-142-1, an inhibitor of particulate guanylyl cyclase, (10(-5) g ml-1) significantly reduced the inhibitory action of fANP on the increase of AVT-induced Isc. These results suggest that fANP and fBNP act through the guanylyl cyclase systems to increase cellular cGMP and modulate AVT-induced epithelial transport in a concentration-dependent manner. It is also suggested that fCNPs have no effect on the natriferic response in the skin of the bullfrog.

Animals↗
PubMed1998

Bronchiolitis obliterans after bone marrow transplantation: evaluation with lung scintigraphy.

Bronchiolitis obliterans (BO) has been described as a main pulmonary complication following allogeneic bone marrow transplantation (BMT). Diagnosis of BO is usually based on clinical findings, pulmonary function tests, and computed tomography scan. However, histological examination of an open-lung biopsy specimen may sometimes be necessary to confirm the diagnosis, despite its relative invasiveness. The ventilation lung scan is another useful but non-invasive diagnostic method. In this study, we present two post-transplant BO cases, each showing different clinical conditions, characterized by delayed wash-out on 133Xe gas and airway depositions on radioaerosol inhalation scans. These methods succeeded in revealing pulmonary obstruction in cases where the pulmonary function tests were within normal range and the high-resolution CT scans (HR-CT) of the chest were only minimally abnormal, suggesting their usefulness as an additional tool in the diagnosis of post-transplant BO, as well as in the follow-up to pulmonary obstruction.

Adult↗
PubMed1998

Periodic fatigue symptoms due to desynchronization in a patient with non-24-h sleep-wake syndrome.

A 43-year-old man complaining of recurrent fatigue symptoms and sleep disorders occurring periodically every 4 weeks was studied. Using a wrist worn actigraphy and an ambulatory rectal temperature monitoring apparatus, his sleep-wake cycle and rectal temperature were measured continuously for 4 months, while diagnostic evaluation and therapeutic interventions were conducted. It was found that after he gave up an attempt to keep to a 24-h-day, a free-running sleep wake pattern appeared but his fatigue symptoms disappeared. An analysis of the relationship between his sleep-wake cycle and the rectal temperature rhythm found that his fatigue symptoms did not appear when both rhythms were synchronized with each other. Artificial bright light therapy entrained him to a 24-h day without relapsing of fatigue symptoms. Desynchronization between a 24-h sleep-wake schedule and his circadian pacemaker may have caused his periodically appearing fatigue symptoms.

Adult↗
PubMed1998

Circadian rhythm sleep disorders in adolescents: clinical trials of combined treatments based on chronobiology.

Delayed sleep phase syndrome (DSPS) and non-24-h sleep-wake rhythm are circadian rhythm sleep disorders that are common in adolescents. Most patients have difficulty adjusting to school life, poor class attendance or refuse to go to school. Since a treatment has not been established, the present paper is presented to propose a strategy for treating circadian rhythm sleep disorders in adolescents, based on our clinical studies. Twenty subjects (12 males and eight females, mean age 16.2+/-1.7 years) participated in the study. The onset of sleep disorder occurred between the ages of 11 and 17. The most common factors affecting the onset of disorders were changes in social environment. The subjects kept a sleep-log for the periods before and during treatments. The treatments were based on chronobiology: resetting the daily life schedule, chronotherapy, regulation of the lighting environment, methylcobalamin, and/or melatonin. Bright light exposure was successful in 10 patients, of whom four were treated with methylcobalamin. Melatonin treatment was successful in two patients (one with and one without chronotherapy). Thirteen of the 20 patients were successfully, treated with therapies based on chronobiology. After consideration of these results, a step-by-step procedure of combined treatments for the circadian rhythm sleep disorders is proposed.

Absenteeism↗
PubMed1998

Antimetastatic efficacy of orally administered ginsenoside Rb1 in dependence on intestinal bacterial hydrolyzing potential and significance of treatment with an active bacterial metabolite.

The antimetastatic effects of orally administered ginsenoside Rb1 (Rb1) and an active metabolite by intestinal bacteria, 20-O-beta-D-glucopyranosyl-20(S)-protopanaxadiol (I), were studied, by using a spontaneous metastasis model produced by subcutaneous injection of Lewis lung carcinoma (LLC) in syngeneic C57BL/6 mice. A thorough analysis of the hydrolyzing potential (transformation by intestinal bacteria) was first done and the data found were positively correlated to the antimetastatic effect of Rb1 through the medium of I. The transformation rate by 41% fecal specimens was less than 10% and consecutive Ginseng administrations were ineffective for the mice with hydrolyzing potential of less than 10%, which limited the antimetastatic efficacy of Rb1- In contrast, the efficacy of I was greater than that of Rb1 and at least comparable to that of S-FU. No effect of I on the primary tumor growth was found, indicating a specific antimetastatic activity. In a leg amputation model with the LLC-line, an effect on survival time of I (8 mg/kg/day) equal to that of 5-FU (10 mg/kg/day) was seen and 38% mice were cured as compared with 13% cured by amputation alone. These findings suggest that the active drug is the bacterial metabolite I which should be administered rather than Rb1.

Administration, Oral↗
PubMed1998

Prevalence of childhood and adolescent atopic dermatitis in a Japanese population: comparison with the disease frequency examined 20 years ago.

To ascertain the prevalence of childhood and adolescent atopic dermatitis in a Japanese population, we clinically observed the total body of 5 to 6-year-old children (994 cases), 7 to 9-year-old children (1,240 cases), 10 to 12-year-old children (1,152 cases), 13 to 15-year-old children (1,670 cases), and 16 to 18-year-old adolescents (2,159 cases). The examination was performed in the spring of 1994-96, when exacerbation of childhood and adolescent atopic dermatitis most frequently occurs in Japan. Atopic dermatitis was observed in 24% of the 5 to 6-year group, in 19% of the 7 to 9-year group, in 15% of the 10 to 12-year group, in 14% of the 13 to 15-year group, and in 11% of the 16 to 18-year group. The prevalence of atopic dermatitis in 9 to 12-year-old children was two times and in 18-year-old adolescents five times as high as in similar age groups examined 20 years ago.

Adolescent↗
PubMed1998

Plasma levels of carboxy terminal propeptide of type I procollagen and pyridinoline cross-linked telopeptide of type I collagen in healthy school children.

The aim of this study was to reveal the relationship of the plasma levels of the carboxy terminal propeptide of type I procollagen (PICP) and the pyridinoline cross-linked carboxyterminal telopeptide domains of type I collagen (ICTP) to age and height velocity (HV), and to compare PICP and ICTP levels in those who have not reached their final height with those who have. PICP and ICTP levels were measured by RIA in 271 healthy children (161M, 110F) aged from 10 to 15 y. The HV was calculated from their health check-up cards. The subjects were divided into two groups in this study: the final height (FH) group whose HV was <1.0 cm/y, and the non-final height (NFH) group whose HV in the last year was > or =1.0 cm/y. PICP and ICTP levels almost paralleled the values of age-related changes of HV. Furthermore PICP and ICTP levels significantly correlated with HV. PICP and ICTP levels of the FH group were higher than those of adults previously reported. The values will be useful as reference for healthy children and growth disorder. Before reaching final height, PICP and ICTP can be useful makers of not only bone turnover but also of linear growth. Bone turnover rate is still increasingly active just after linear growth has been completed, and then it become similar to the levels of adults.

Adolescent↗
PubMed1998

Incidence of febrile convulsions in children with congenital hypothyroidism.

Brain excitability has been inconsistently reported to be increased both in hypo- and hyperthyroidism, but there have been few studies on the effects of thyroid hormones on brain excitability in children. With this in mind, we investigated the incidence of febrile convulsions (FCs) among patients with congenital hypothyroidism, who have been taking L-thyroxine since the age of 1 month. The incidence of FCs among congenital hypothyroid patients was 1.6% (1/63) which was significantly low (p < 0.05) compared with that of normal control children who visited our hospitals as outpatients (28/341, 8.2%) and that of others (322/3301, 9.8%) investigated 33 years ago in the same area. The incidence of FC among siblings of the 63 patients (7/74, 9.5%) was not statistically different from the controls. At least 8 of the 126 parents (6.4%) had experienced FC, however, only one child was affected in the 8 families. In conclusion, it seems likely that patients with congenital hypothyroidism on regular L-T4 replacement are less prone to experience FC. More studies on the incidence of convulsive disorders in children with thyroid diseases are needed to clarify the effects of thyroid hormones on brain excitability.

Adolescent↗
PubMed1998

The blood-gas partition coefficient of xenon may be lower than generally accepted.

The blood-gas partition coefficients of xenon, reported more than 25 yr ago in the literature, vary considerably from 0.13 to 0.20. Consequently, we have determined this variable by directly injecting xenon-saturated blood into a gas chromatograph-mass spectrometer. This technique yielded a blood-gas partition coefficient for xenon of 0.115 (95% confidence interval 0.107-0.123). The solubility in water measured identically was 0.096, consistent with the reported value of 0.085. These data and a detailed review of the literature strongly suggest that the blood-gas partition coefficient of xenon may be lower than the generally accepted value of 0.14.

Anesthetics, Inhalation↗
PubMed1998

Latent cerebral artery stenoses on magnetic resonance angiography in a patient diagnosed as probable Alzheimer disease.

A 65-year-old woman with hypertension developed slowly progressive memory disturbance and disorientation. She was diagnosed as having Alzheimer-type dementia according to clinical criteria. Later her cognitive deterioration was noted to fluctuate in parallel to her blood pressure. Magnetic resonance angiography and single photon emission computed tomography showed bilateral middle cerebral artery stenoses and middle cerebral artery watershed dominant hypoperfusion. It is postulated that the patient's cognitive disturbance may have originated from vascular lesions.

Aged↗
PubMed1998

Observational assessment of patient's sleep complaints in the coronary care unit.

Sleep-wake disorders are common in patients who are treated in coronary care units (CCU). We report a clinical trial aimed at developing an observational assessment of patients sleep complaints in a CCU. Thirty-four inpatients with coronary heart diseases in the CCU (Tokyo Metropolitan Hiroo General Hospital) participated in the study. The patient's sleep state was assessed by nursing staff and classified as wakefulness, drowsy and asleep according to a semi-structured observation. Subjective sleep feelings upon rising was also investigated. Sleep disruptions during the latter half of the night was found to be an important determining factor of sleep feeling upon rising.

Confusion↗
PubMed1998

Continuous measurement of temperature in non-24 hour sleep-wake syndrome.

The onset of the low temperature (LT) zone which was defined as a period when the rectal temperature was below its daily mean is a convenient circadian phase marker. In this study, we document three cases of non-24 h sleep-wake syndrome in which identification of the LT zone as an evening circadian phase marker contributed to clinical judgments. We found that the LT zone was correlated well with dim light melatonin onset. Moreover, calculating the LT zone was useful in determining phase position in irregular sleep pattern and in determining the timing of bright light therapy.

Adult↗
PubMed1998

Human time production under constant routine.

Previous reports have suggested that human time production of several seconds fluctuates across the day. In order to test whether human time production was controlled by the circadian process or by the homeostatic process, we investigate diurnal fluctuation of human time production under constant routine conditions. We found a common circadian feature in time production tests of 10 s by calculating Z-score for each subject; afternoon troughs and morning peaks. These results may suggest that human time production was modulated by the circadian process.

Adult↗
PubMed1998

Twenty-four hour profiles of four hormones under constant routine.

We studied the circadian features of melatonin, cortisol, thyroid stimulating hormone (TSH), and growth hormone (GH) together with rectal temperature during 36 h continuous forced wakefulness without physical exercise under dim light condition (constant routine). Subjects consisted of four healthy men aged 22-24 years. Blood sampling was conducted hourly, and food and water were supplied bi-hourly during the constant routine. Melatonin, TSH and cortisol displayed clear circadian rhythms under constant routine condition. While GH secretion was unlikely to be driven solely by the circadian pacemaker, its suppression round BT nadir may indicate that GH secretion was modulated to some extent by circadian rhythm.

Adult↗
PubMed1998

Effects of evening light on body temperature.

Six healthy male subjects aged 21-35 years participated in the present study. The subjects were exposed to dim light (150 lux) or bright light (3000 lux) at eye level, from 19.00 to 21.30 h for 5 days. Rectal temperature and wrist activity were monitored throughout the study period. Rectal temperature nadir was delayed significantly after the bright light exposure. Ease in sleep initiation and overall sleep quality, measured by questionnaire, were aggravated significantly by the evening bright light exposure. These results suggest that strong illumination at night may disturb nocturnal sleep.

Adult↗
PubMed1998

Melatonin treatment for circadian rhythm sleep disorders.

We administered 1-3 mg melatonin to 11 patients (eight men, three women, aged 16-46 years) with circadian rhythm sleep disorders; nine with delayed sleep phase syndrome and two with non-24-hour sleep-wake syndrome. Sleep logs were recorded throughout the study periods and actigraph and rectal temperature were monitored during treatment periods. Melatonin was administered 1-2 h before the desirable bedtime for expected phase-shifting, or 0.5-1 h before habitual bedtime for gradual advance expecting an hypnotic effect of the melatonin. Melatonin treatments were successful in 6/11 patients. Timing and dose of melatonin administration, together with its pharmacological properties for circadian rhythm sleep disorders, should be further studied.

Adolescent↗
PubMed1998

Trials of bright light exposure and melatonin administration in a patient with non-24 hour sleep-wake syndrome.

We report a patient with non-24 h sleep-wake syndrome (non-24) whose free-running sleep-wake cycle was successfully treated with both scheduled bright light exposure and melatonin treatment. In the present study, morning bright light as well as evening melatonin phase-advanced sleep-wake cycles and melatonin rhythm. Both these procedures achieved appropriate entrainment to a 24 h day. However, the patient did not continue morning bright light therapy after the discharge. Rising at appropriate times in the morning for bright light therapy was difficult for him to continue. Melatonin treatment was better tolerated because of its ease of application.

Adult↗