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Biomedical subjects

Y Koike

Publications and source records attributed to Y Koike.

At least 307 records · Page 17Linked to original sources
PubMed1987

[Fundamental study of amikacin in the newborn].

Amikacin (AMK) is one of the aminoglycoside antibiotics, derived from kanamycin A. It has a broad spectrum against Gram-negative rods but its usefulness is mainly in the efficacy against Gram-negative rods which do not respond to commonly used kanamycin and gentamicin. The efficacy and the safety of AMK have been confirmed in children and mature babies. In the trial reported here, we evaluated AMK in newborn. 1. AMK was administered to 13 mature and 8 premature babies via intramuscular injection or intravenous drip infusion for 30 minutes or 1 hour and its blood concentrations were determined. These administrations resulted in blood concentrations 4.47-9.67 mcg/ml with dosage levels 2.3 mg/kg (mean 6.92 +/- 1.66 mcg/ml), 5.86-26.1 mcg/ml with 5-6 mg/kg (mean 15.4 +/- 4.63 mcg/ml) and 27.5-37.7 mcg/ml with 7.5 mg/kg (mean 31.0 +/- 4.76 mcg/ml). Blood half-lives were 1.88 to 9.66 hours, showing longer half-lives in younger subjects. 2. Exchange transfusion (150-180 ml/kg) was performed in 5 mature babies and the variation of blood concentrations of AMK was studied. The study showed that blood concentrations of AMK after the exchange transfusion were 25.6-41.5% (mean 32.3 +/- 5.4%) of the levels detected before the transfusion.

Amikacin↗
PubMed1986

Role of the nucleus of the optic tract in monkeys in relation to optokinetic nystagmus.

Nine monkeys were used in order to clarify the role of the nucleus of the optic tract (NOT) in the generation of optokinetic nystagmus (OKN). In 3 monkeys whose NOTs were almost totally damaged, optokinetic stimulus toward the lesioned side failed to generate either eye deviation or OKN and revealed only voluntary saccades, whereas that toward the side contralateral to the lesion generated normal gain of OKN. The phenomenon was identical in either monocular or binocular stimulation. In two of 3 monkeys whose NOTs were partially destroyed, optokinetic stimulus toward the lesioned side produced OKN, but the gain of OKN, but the gain of OKN was at maximum less than 60% in both binocular and monocular stimulation. In the remaining one monkey whose NOT was injured, but superficially, OKN showed normal gain in both directions. In 3 other monkeys whose NOTs were spared, this OKN asymmetry was not observed. Pursuit and saccadic eye movements were normal in all NOT-lesioned monkeys. Visually induced eye movements in the vertical axis were likewise normal. The present experiment suggests that the NOT in monkeys may be the first relay station in the horizontal optokinetic path and that in primates as in non-primates both crossed and uncrossed fibers reach motor centers for OKN via the NOT.

Animals↗
PubMed1986

Differential effects of cimetidine and ranitidine on imipramine demethylation and desmethylimipramine hydroxylation by human liver microsomes.

The effect of cimetidine and ranitidine on the demethylation of imipramine (IMI) and on the hydroxylation of desmethylimipramine (DMI) was studied in microsomes from four human livers. Cimetidine inhibited both demethylation of IMI and 2-hydroxylation of DMI, whilst the effect of ranitidine was not statistically significant. 2-hydroxylation of DMI is probably mediated by debrisoquine hydroxylase, a cytochrome P-450 isozyme that is monogenically controlled. The results suggest that cimetidine inhibits this enzyme.

Cimetidine↗
PubMed1986

Risk factors related to hearing impairment and screening with the Crib-O-Gram.

A "Crib-O-Gram" was employed for an automatic screening of hearing impaired newborns. A series of 502 neonates were tested, and 57 babies were judged to be "REFER." These "REFER'd" subjects were further examined with ABR, and 4 hearing impaired subjects were found. A detailed history was available in 427 neonates, and "risk factors" related to hearing impairment were investigated. The incidence of "REFER" judgment was found to be significantly higher for the group of neonates with risk factors than for those without risk factors. The rate of "REFER" judgment was computed for each risk factor, and the phi-coefficient of association was calculated to study the statistical relationship between the "REFER" judgment and each risk factor. A significant relationship was confirmed for anatomic malformations, positive family history of deafness, and congenital perinatal infection. The relationship between the existence of hearing impairment and each risk factor was similarly studied. Congenital perinatal infection and family history of deafness were significantly associated with hearing impairment, although anatomic malformation was not significantly related. The quantification theory (Hayashi type II) was applied to calculate a relative weight of each risk factor in reference to both the REFER judgment and hearing impairment. It was pointed out that proper weighting of each risk factor may be useful in improving the efficiency of screening.

Hearing Disorders↗
PubMed1986

Computer analysis of optokinetic nystagmus for clinical usefulness.

A computer program was developed for on-line analysis of nystagmus parameters using a microcomputer (SORD M243EX). In this paper, the clinical utilities of microcomputer analysis of optokinetic nystagmus (OKN) were described, and quantitative analysis of each parameter of OKN was performed in 20 normal subjects and 49 patients with central nervous system (CNS) disorders. The average gain was accurately measured and the maximal stimulus velocity during which time the gain was more than 0.8, was termed as the "optokinetic adaptation limit (OAL)," and used as a clinical index for evaluation of OKN abnormalities. All patients in the present study showed a remarkable decrease in OAL. The differences in OAL among these patients at each level of lesion site, however, proved to be statistically insignificant. The relationship between the direction of OKN limitation and the lesion side was investigated. In all patients who had lesions on the thalamus, midbrain, and cerebellum, OKN limitation was observed toward the lesion side. The OKN limitation, however, was seen toward the intact side in 7 of 11 patients with medullary lesions and in 2 of 11 patients with cerebellopontine angle (CPA) tumors. hence, OKN in a useful diagnostic tool for the assessment of infratentorial lesions and computer analysis of OKN may be clinically useful.

Brain Diseases↗
PubMed1986

Electronystagmographic assessment of cerebellar lesions.

Remarkable progress has been achieved in the neurophysiological study of the cerebellum. Based on these neurophysiological data, electronystagmographic (ENG) assessment of cerebellar lesions was made to ascertain to what extent cerebellar lesions could be diagnosed. In 13 patients out of 17 whose lesions were mainly localized on one side through CT, cerebellar lesions could be diagnosed by electronystagmographic findings. In the 1 patient with amyotrophic lateral sclerosis of the remaining 4, asymptomatic cerebellar infarction was detected unexpectedly through CT. In the remaining 3 patients, differential diagnosis from brainstem lesions was difficult to evaluate on the basis of ENG findings. In 13 patients showing cerebellar signs and symptoms, pursuit eye movements, optokinetic nystagmus (OKN), and fixation-suppression of caloric nystagmus were impaired on both sides, suggesting large mass effects upon the bilateral brainstem. However, either rebound nystagmus or opposing positioning nystagmus characteristic of cerebellar lesions was detected in 13 patients (81%). The same was true in patients with bilateral cerebellar lesions. ENG test, however, could not detect any patients who showed neither cerebellar signs nor symptoms. Further investigations are needed to supplement the gap between basic and clinical research.

Cerebellar Diseases↗
PubMed1986

Structural studies on N-acetylmannosaminuronic acid-containing and glucuronic acid-containing teichuronic acids in the cell wall of Bacillus megaterium AHU 1375.

Structural studies were carried out on two kinds of teichuronic acid-glycopeptide complexes (designated as TU-GP-I and TU-GP-II) isolated from lysozyme digest of N-acetylated cell walls of Bacillus megaterium AHU 1375 by ion-exchange chromatography and gel chromatography. TU-GP-I, accounting for about 25% of the cell walls, contained N-acetylmannosaminuronic acid, N-acetylglucosamine, glucose, galactose, glycerol, and phosphorus in an approximate molar ratio of 1:1:2:1:0.5:0.5, together with small amounts of glycopeptide components. TU-GP-II, accounting for about 9% of the cell walls, contained glucuronic acid, glucose, and fucose in a molar ratio of about 2:1.5:1, together with small amounts of glycopeptide components. The results of analyses involving Smith degradation, chromium oxidation, methylation, acetolysis, and H-NMR measurement led to the conclusion that the polysaccharide chain of TU-GP-I comprised repeating units,----6) Glc(alpha 1----3)-ManNAcUA(beta 1----4)[Gal(alpha 1----3)][Glc(beta 1----6)]GlcNAc(beta 1----. About half of the repeating units were substituted by glycerophosphoryl residues at C-6 of the beta-glucosyl residues linked to the N-acetylglucosamine residues. By means of a similar procedure, the polysaccharide chain of TU-GP-II was shown to comprise repeating units,----4)GlcUA(alpha 1----3)GlcUA(alpha 1----3)Glc(alpha 1----3)Fuc(alpha 1----, of which about half were substituted by alpha-glucosyl residues at C-3 of the 4-substituted glucuronosyl residues.

Bacillus megaterium↗
PubMed1986

[Multiple giant aneurysm--a case report].

We report a case of five aneurysms, including three giant aneurysms, a pair of symmetric aneurysms, and two fusiform aneurysms. The initial clinical symptom was a cerebral ischemic attack. On admission, the patient complained of sudden onset of speech disturbance. Physical examination showed left hemiparesis. Radiological studies, including computed tomography and cerebral arteriography, revealed multiple low density areas bilaterally in the basal ganglia and three fusiform giant aneurysms bilaterally in the middle cerebral arteries and basilar artery. Considering the difficulty of surgical treatment, the patient was discharged. Six months later, complaining of right hemiparesis and total dysphasia, the patient was readmitted to our department. CT scan on admission revealed no changes except for ischemic changes. During the second admission, another attack of subarachnoidal hemorrhage due to rupture of the left middle cerebral artery aneurysm occurred, and the patient died. Autopsy was performed, and two more aneurysms, not visualized in the former studies, were found in the right anterior communicating artery and the cortical branch of the right middle cerebral artery. The occurrence of aneurysms in such a fashion as seen in the present case is to be very rare in the aspect of the size, the multiplicity and the bilaterally development.

Cerebral Angiography↗
PubMed1986

[Sex differences in the physical dependence on barbital in rats].

Sex differences in physical dependence on barbital (BAR), which is not readily metabolized in rats, were studied by the drug-admixed food method. The concentration of BAR in the food was gradually increased from 1 and 2 up to 6 and 8 mg/g food concurrently available to each rat over a period of 36 days in both male and female Sprague-Dawley rats. Sedation and muscle relaxation were observed in males at the 4 and 6 mg/g condition and to a greater degree at 6 and 8 mg/g of food. This effect was seen only at the highest drug concentration, 6 and 8 mg/g food, in females. Physical dependence was assessed in both sexes after substitution of normal food for the BAR-admixed food. Various signs of BAR withdrawal were observed including vocalization, irritability, muscle rigidity, tremors and convulsions. The incidence of convulsions was 76.9% in females and 45.5% in males, respectively. Maximum weight loss was 15.4% in females and 12.1% in males. However, brain BAR concentrations in the male rats were higher than that in the female rats 9 hours before onset of withdrawal and at all later time points tested. Thus, we have demonstrated that weak sex differences in physical dependence on BAR exist and suggest that this difference resulted from a difference in CNS sensitivity to BAR.

Animals↗