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Biomedical subjects

M Miyao

Publications and source records attributed to M Miyao.

At least 109 records · Page 6Linked to original sources
PubMed1993

[Intraocular penetration of current antibiotics].

We studied the intraocular penetration of 42 antibiotics in white rabbit eyes between 1980 to 1990 in our department. The parenteral route (intravenous, intramuscular): the ratios of maximum aqueous humor to serum level were 5.28-11.6% in penicillins (PCs), 5.95-20.17% in cephems and 13.4-30.27% in aminoglycosides (AGs). The aqueous concentration of antibiotics reached a peak within 1/4-1 hour after injection. Oral administration: the ratios of aqueous to serum level were 8.52-20.6% in PCs, 3.62-20.11% in cephems, 22.8-75.8% in macrolides (MLs) and 6.38-23.6% in quinolones. The aqueous concentration of antibiotics reached a peak within 1-4 hours after oral administration. The ratio of aqueous to serum level was the highest in MLs. The aqueous level reached a peak faster and the ratio of aqueous to serum level was higher by injection than by oral administration.

Administration, Oral↗
PubMed1993

[A case of hypothalamic hamartoma with gelastic seizures, precocious puberty, poly- and syndactyly].

We reported a 6-month-old boy, patient of hypothalamic hamartoma with a rare association of poly- and syndactyly, which developed gelastic seizures and precocious puberty. His birth was complicated by poly- and syndactyly in both hands and polydactyly in both feet, but other physical signs were normal. At 5 month of age, he visited our hospital because of a suspected seizure. On admission, physical and neurological examinations revealed increased size in penis and testes, and delayed psychomotor development. Gelastic seizures occurred up to 100 times a day, and were resistant to many anticonvulsants. Ictal EEG showed bursts of generalized high voltage slow waves. His serum LH and testosterone levels were elevated for his age. Brain CT and MRI demonstrated a hypothalamic mass lesion, which proved to be hamartoma by biopsy.

Epilepsy↗
PubMed1992

Acute effects of tobacco smoking on the autonomic nervous system in comparison with alcohol drinking.

A total of 21 male university students were used to investigate the acute physical effects on the autonomic nervous system of two adult daily habits; smoking and drinking. A tobacco loading trial and an alcohol loading trial were conducted, keeping the conditions as uniform as possible. The nine subjects were instructed to smoke two cigarettes in 10 minutes, and their blood pressure, heart rate, and pupil diameter were measured. In addition, blood samples were taken 30 minutes after initiation of the trial, and the level of nicotine in the samples was measured (Trial 1). The twelve subjects were instructed to drink one large bottle of beer in 10 minutes, and the same parameters were measured. (Trial 2: trial for comparison). The pupil diameter decreased significantly 30 minutes after the subjects started smoking. Also, the heart rate increased suddenly as soon as the subjects started smoking, and the increase in the heart rate was pronounced for the 10 minutes that they were smoking. The maximal and minimal blood pressures generally did not fluctuate greatly. On the other hand, the pupil diameter tended to decrease slightly as soon as the subjects began drinking, and no significant difference in this value was noted. Also, even though the heart rate tended to increase slightly, no significant difference was noted in this value. In contrast, the maximal blood pressure increased significantly when the subjects started drinking, and tended to decrease gradually after they finished drinking.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Analysis of factors related to hypertension in Japanese middle-aged male workers.

A total of 789 Japanese male transport service workers between the ages of 35 and 50 were used as subjects in an analysis of daily lifestyle factors related to hypertension. Multiple logistic analysis showed positive dose-response relations between hypertension and age, obesity and alcohol consumption. Age and obesity were factors having a linearly increasing odds ratios for hypertension (including borderline cases and those under treatment). Alcohol consumption of 56 g ethyl alcohol per day or more had an odds ratio about double that of those who did not drink. Smokers had 1/2 the odds ratio of non-smokers. Subjects working a 24-hr shift comprised mostly of standby duty showed a slightly lower rate of hypertension, but it was statistically insignificant.

Adult↗
PubMed1991

Enhancement by chloride ions of photoactivation of oxygen evolution in manganese-depleted photosystem II membranes.

The Mn cluster that catalyzes photosynthetic oxygen evolution was removed from the photosystem II (PSII) complex by treating PSII membranes with 1.0 mM NH2OH with concomitant inactivation of oxygen evolution. The cluster was reconstituted by incubating the treated membranes with 1.0 mM Mn2+, 20 mM Ca2+, 10 microM 2,6-dichlorophenolindophenol, and Cl- under illumination with continuous or flashing light to restore the oxygen-evolving capacity. This light-dependent activation (photoactivation) of oxygen evolution did not occur to a significant extent at 3 mM Cl-, but markedly accelerated at higher Cl- concentrations without showing a saturation phenomenon even at 1 M Cl-. At 10 mM Cl- only about 10% of the oxygen-evolving activity before NH2OH treatment was restored by 5-min illumination with continuous light, whereas at 600 mM Cl- about 60% of the original activity was recovered. This acceleration resulted from at least two different actions of Cl-: (1) stabilization of the intermediate state involved in the photoactivation process and (2) increase in the quantum yield of photoactivation. The stabilization of the intermediate was saturated at about 150 mM Cl-, whereas the increase in yield did not show saturation. The Cl(-)-induced increase in quantum yield did not involve any changes in the affinity of either Mn2+ binding or Ca2+ binding for photoactivation, but was rather ascribed to a protective effect of Cl- against inhibition of photoactivation by high concentrations of Mn2+. We also found that removal of the extrinsic 33-kDa protein from the PSII complex increased the Cl- requirement for photoactivation.

Binding Sites↗
PubMed1991

Circulatory disturbances of the foot in vibration syndrome.

Circulatory disturbances of the foot in patients with vibration syndrome were studied by measuring the skin temperature of both index fingers and great toes through a 3-min immersion of the right foot in cold water at 10 degrees C. Subjects included 11 patients with vibration-induced white finger (VWF) [VWF(+) group], 12 patients without VWF [VWF(-) group], and 20 healthy referents not exposed to vibration. Patients were all male chain saw operators who had scarcely been exposed to vibration of the foot. The prevalence of coldness felt in the upper and lower extremities was greater than 90% in the VWF(+) group, about 60% in the VWF(-) group, and less than 10% in the referents. The extent of the coldness was greatest in the VWF(+) group. The skin temperature of both fingers and toes was lowest in the VWF(+) group, somewhat higher in the VWF(-) group, and highest in the referents both before and after immersion. These findings indicate that patients with vibration syndrome, especially those with VWF, have circulatory disturbances in the foot as well as in the hand. The disturbances in the foot may be related to long-term repeated vasoconstriction in the foot induced by hand-arm vibration through the sympathetic nervous system.

Aged↗
PubMed1991

Effect of vibration frequency on finger blood flow.

A total of 18 healthy subjects (9 men and 9 women) 20-35 years of age were used to study the effect of vibration frequency on finger blood flow. Seven vibration frequencies of 16, 31.5, 63, 125, 250, 500 and 1,000 Hz, at vibrational accelerations of 10 m/s2 (rms: root mean square) or 50 m/s2 (rms), with the exception of 16 Hz, which was measured at only 10 m/s2 (rms), were randomly applied to the palm of the right hand for 1 min at intervals of about 3 min. Finger blood flow was measured simultaneously in both the right and the left middle fingers with a blood flowmeter using a thermal diffusion method and in the left middle finger with a laser Doppler flowmeter. The experiments were performed in an artificial climate chamber set at 23 degrees C air temperature and 50% humidity. Relatively great responses were observed at frequencies of 31.5-63 and 250-500 Hz on the exposed and unexposed sides, respectively, as measured with a blood flowmeter using a thermal diffusion method and at 31.5-63 as well as 500 Hz on the unexposed side with a laser Doppler flowmeter. These results may be related to Meissner's and pacinian corpuscles.

Acoustics↗
PubMed1991

Effects of deoxyadenosine on ribonucleotide reductase in adenosine deaminase-deficient lymphocytes.

To explore the relationship between ribonucleotide reductase and immunodysfunction in adenosine deaminase deficiency, the effects of deoxyadenosine on ribonucleotide reductase in ADA-deficient lymphocytes was investigated. An assay system for ribonucleotide reductase in intact permeabilized lymphocytes was developed to approximate physiological conditions. The activity of cytidine diphosphate (CDP) reductase in resting but not in proliferating lymphocytes in culture was inhibited by 1 to 10 mumol/L deoxyadenosine. The resting cells were protected from the toxicity of 1 mumol/L deoxyadenosine by 5 mmol/L nicotinamide or 30 mumol/L deoxycytidine and from that of 10 mumol/L deoxyadenosine by 30 mumol/L deoxycytidine. These findings suggest that depletion of nicotinamide adenine dinucleotide might be the principal cause of death in resting lymphocytes with ADA deficiency. It is concluded that the mechanism of deoxyadenosine toxicity on non-replicating lymphocytes, which may not be mediated by ribonucleotide reductase inhibition, is closely related to the mechanism of immunodysfunction in patients with ADA deficiency.

Adenosine Deaminase↗
PubMed1991

High incidence of sleep apnea syndrome in a male diabetic population.

In order to study the possible relationship between sleep apnea syndrome (SAS) and diabetes mellitus, we first examined the prevalence of SAS among 12,787 general patients (6554 males and 6233 females) who visited Katsumata Hospital at Nagoya, Japan. Among them, thirty-five males and five females were diagnosed as having SAS. The male patients were statistically analysed by the corrected Mantel-Haenszel chi-square test taking the body type into account, and it was found that the prevalence of SAS was significantly high both in a diabetic population and in a hypertensive one. Among 40 SAS patients of both sexes, 34 were given a glucose tolerance test (GTT) with oral administration of 75 g glucose. Thirteen showed a diabetic pattern, 12 a borderline pattern and only 9 had a normal pattern. All 13 diabetic patients had non-insulin-dependent type diabetes (NIDDM). The present results showed that SAS has a close relationship not only to hypertension but also to NIDDM.

Adolescent↗
PubMed1991

[Computed cranial tomography, magnetic resonance imaging and brain echo imaging in Japanese B encephalitis].

We reported computed cranial tomography (CCT), magnetic resonance imaging (MRI) and brain echo imaging in Japanese B encephalitis. The result were assessed in comparison with the clinical feature of the disease. CCT of the three patients showed low density in thalamus and basal ganglia. In two, the lesions were detected in the acute phase, and changed to high density in the chronic phase. Their prognosis was poor, psychomotor delay and paresis persisted. Among the previously reported sixteen patients of Japanese B encephalitis in Japan, the four developed thalamic lesions on CCT and the prognosis was poor in all patients. Brain echo detected the lesions in the acute phase before CCT visualised them clearly. MRI demonstrated thalamic hemosiderin deposits and calcification. These findings were compatible with the pathological findings, or past hemorrhage and organization. The distribution of the lesion were closely connected with the prognosis.

Brain↗
PubMed1991

The deterioration of visual acuity by exercise under a mesopic vision environment.

Visual acuity deteriorated following 15-minute bicycle ergometer pedaling under the condition of a mesopic vision environment. Visual acuity decreased sharply as the load increased. The visual functions which changed significantly after the exercise in the mesopic vision environment were visual acuity (deterioration) and accommodative near point distance (extension).

Accommodation, Ocular↗
PubMed1991

Change of pupil size as a function of exercise.

Exercise was found to dilate the pupil area while the exercise took place, while the area showed constriction following the exercise period. Exercise-induced change in the size of the pupil was minimal. Pupillary dilation was greatest under conditions of maximal exercise. In exercise under a consistent load, pupillary dilation increased as the exercise time was prolonged. With lower lighting, there was virtually no dilation with exercise.

Adult↗
PubMed1991

Working hours and fatigue of Japanese flight attendants (FA).

There have been some reports concerning high complaint rates of fatigue or fatigue-related symptoms including lower back pain in flight attendants (FA). Thus, the relations of working conditions with work stress and fatigue symptoms were studied chiefly by focusing on working hours. From analysis of the time-table and fatigue symptoms of workers on international flights, it was suspected that there were some work-related factors jointly causing serious FA fatigue symptoms; night time and early morning work, long flight hours and a large time difference, thus disturbing their biological rhythms. On domestic flights, showing up early in the morning and debriefing late in the night were often observed together with a highly irregular FA time schedule. By statistical analyses, some factors including long working hours, frequent landing and late debriefing hours were considered to contribute significantly to the high fatigue complaint rates. Thus, it should be emphasized that many countermeasures are necessary to improve FA working conditions including working hours, rest on the airplane (ONO et al., 1990) and sleep during layover, in order to reduce their work stress and fatigue symptoms.

Aerospace Medicine↗
PubMed1991

Effects of color CRT display on pupil size in color-blind subjects.

The effects of color cathode ray tube (CRT) display on the pupil size in color-blind subjects were studied experimentally. Red, magenta, green, cyan, yellow, and white were presented on the CRT. Five protan subjects, five deutans, and five normal subjects were tested using infrared pupillography. In the protan group, the pupils were significantly less sensitive to red (wavelength: 600 nm) targets compared to the other colors. In the deutans and the control group, there were non-significant changes in pupil size in response to the colors. Dominant wavelengths above 600 nm in color CRTs should be avoided in routine work presentation because of less sensitivity in protanopias.

Adult↗
PubMed1991

[Intraocular penetration of DR-3355, a new quinolone derivative].

We studied the intraocular penetration of DR-3355, a new quinolone derivative in white mature rabbits. DR-3355 concentration in the aqueous humor reached the maximum, 1.06 micrograms/ml, at 2 hours after oral administration of 20 mg/kg in single dose. Six hours after it was 0.37 micrograms/ml. At 2 hours, the concentration ratio in the aqueous humor and serum was 23.3%. The pharmacokinetic parameters of DR-3355 levels in both of the aqueous humor and serum were: Cmax, 1.02 micrograms/ml and 4.56 micrograms/ml; Tmax, 1.42 hours and 1.47 hours; T 1/2, 0.96 hours and 1.57 hours; and AUC, 3.91 micrograms.hr/ml and 19.70 micrograms.hr/ml, respectively. At 2 hours after oral administration, the ocular tissue concentrations were 3.84-16.10 micrograms/g in the outer parts of the eye, and 0.70-13.52 micrograms/g or ml in the inner parts of the eye. Those concentrations decreased to about 1/2 to 1/32 in the outer parts, and 1/2 to 1/7 in the inner parts of the eye at 6 hours. Those ocular tissue concentrations of DR-3355 exceeded the MIC90 of the compound against various bacteria of ocular pathogens, such as Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella pneumoniae and Serratia marcescens.

Administration, Oral↗