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Biomedical subjects

H Sakata

Publications and source records attributed to H Sakata.

At least 235 records · Page 13Linked to original sources
PubMed1984

Saccade and blinking evoked by microstimulation of the posterior parietal association cortex of the monkey.

Electrical stimulation with microelectrodes of the posterior parietal association cortex in alert behaving monkeys elicited saccadic eye movements and blinking. The sites in which saccades were elicited by electrical stimulation were concentrated in the anteromedial part of area 7a, especially in the posterior bank of the intraparietal sulcus, in a region which sends efferent projections to the frontal eye field and the superior colliculus, but they were also found in the posterolateral part of area 7a. Compared with the frontal eye fields and the superior colliculus, the threshold current for eliciting saccades was relatively high, on the average 86 microA. Moreover, the elicitation of saccade was inconsistent even with suprathreshold stimulation and suppressed during visual fixation. Latencies of the saccades were relatively long, on the average 50ms; they were longer in the posterolateral part than in the anteromedial part. Direction and amplitude of evoked saccades depended on the site of stimulation, but was independent of eye position in most cases. However, "goal-directed" saccades which depended on initial eye position were elicited in three penetrations in the posterolateral part of area 7a. The threshold of mainly in the lateral part of area 7a. The threshold of blinking was 70 microA and the latency was 50 ms on the average. In contrast to saccades, blinking was elicited constantly with each stimulus even during attentive fixation. We occasionally recorded single unit activity at the site of stimulation with the same electrodes. More than half of the units recorded at the site of blinking responded to approaching visual stimulus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Enzyme-linked immunosorbent assay compared with neutralization tests for evaluation of live mumps vaccines.

Mumps-specific antibody levels before and after vaccination with live mumps vaccines were determined by enzyme-linked immunosorbent assay (ELISA) and neutralization tests. A correlation was found between neutralization titers and optical density in ELISA. However, postvaccination sera from some vaccinees who failed to seroconvert by neutralization contained significant levels of mumps-specific antibody detectable by ELISA. In some of these serum specimens, the antibody directed to the F polypeptide of mumps virus was predominant. Most sera positive in ELISA neutralized mumps virus upon the addition of fresh guinea pig serum to the virus-serum mixture.

Antibodies, Viral↗
PubMed1984

[Clinical and pharmacokinetic evaluation of ceftriaxone in children].

Twenty-eight pediatric patients were treated with ceftriaxone (Ro 13-9904, CTRX) in the doses ranging from 8.75 to 25 mg/kg every 12 hours for 3.5 to 11.5 days, and the clinical efficacy and side effects were evaluated. Among the 21 children with bacterial infections including pneumonia, acute bronchitis, otitis media, tonsillitis and urinary tract infections, the results were excellent in 9, good in 11, and fair in 1 patient. Out of the 28 patients, 2 patients had diarrhea, 3 patients had slightly elevated serum concentrations of transaminases, and 2 patients showed eosinophilia. The serum concentrations of CTRX in 5 children ranged from 50.0 to 93.8 micrograms/ml (mean 75.0 micrograms/ml) at 15 minutes and from 10.2 to 15.6 micrograms/ml (mean 13.4 micrograms/ml at 6 hours after 10 mg/kg intravenous bolus injection of CTRX. The serum half-lives were from 2.61 to 8.30 hours (mean 6.16 hours), and urinary recovery rates were from 43.3 to 58.0% (mean 48.5%) during 0-6 hours and from 52.0 to 66.1% (mean 59.4%) during 0-12 hours. After 20 mg/kg intravenous bolus injection of CTRX in 4 children, the serum concentrations of CTRX were from 118.8 to 162.5 micrograms/ml (mean 139.1 micrograms/ml) at 15 minutes and from 18.0 to 21.1 micrograms/ml (mean 19.2 micrograms/ml) at 6 hours. The serum half-lives were 4.07 to 6.34 hours (mean 5.13 hours), and urinary recovery rates were 38.6 to 51.1% (mean 45.4%) during 0-6 hours and from 54.8 to 64.0% (mean 59.0%) during 0-12 hours. Patients with impairment of renal function were excluded from this pharmacokinetic study.

Adolescent↗
PubMed1984

[Clinical and pharmacokinetic evaluation of ceftazidime in children].

Forty-two pediatric patients were treated with ceftazidime ( CAZ ) in the doses ranging from 45.6 to 120 mg/kg/day for 2 to 10 days, and the clinical efficacy and side effects were evaluated. Among the 37 children with bacterial infections including pneumonia, bronchitis, tonsillitis, croup, cervical lymphadenitis, abdominal abscess and urinary tract infections, the results were excellent in 22, good in 12, fair in 2, and poor in 1 patient with pneumonia. Out of the 42 patients, 5 cases showed eosinophilia, but no clinical sign such as rash, fever or diarrhea, attributable to CAZ was observed during the study. The serum concentrations of CAZ in 4 patients ranged from 60.8 to 71.0 micrograms/ml (mean 66.1 micrograms/ml) at 30 minutes and from 0.5 to 1.2 micrograms/ml (mean 0.8 micrograms/ml) at 8 hours after 20 mg/kg intravenous bolus injection of the antibiotic. The mean serum half-life was 1.42 hours (85 minutes). Patients with impairment of renal function were excluded from this study.

Age Factors↗
PubMed1984

[An experimental study of the effect of fluorocarbon perfusion for amputated limb preservation. The effect of inhibition for replantation toxemia and muscle tissue destruction].

In replantation surgery, it is widely accepted that replantation toxemia or muscle destruction in replanted limbs might occur after a long time of ischemia. Their possibilities are particularly high after replantation of the amputated limbs which contain more muscle tissue than tendon and bones. The present study was performed to investigate the efficacy of fluorocarbon (FC: artificial blood) perfusion to the amputated limbs in preventing these problems after replantation. The hind limbs of dogs were completely amputated at mid-thigh. Amputated limbs were divided into two groups. One was stored in ice water and the other at room temperature for six hours. Each group was furthermore divided into four subgroups. The amputated limbs were perfused with oxygenated FC or Hartmann's solution before replantation and remaining limbs were not perfused. All of them were replanted under an operating microscope. The results were as follows: Perfusion with FC had an inhibiting effect on the anaerobic metabolism in an amputated limb and also decreased the rate of death due to replantation toxemia. Perfusion with FC was effective for inhibiting leakage of creatine phosphokinase from the replanted limb and preventing muscle destruction. Both these effects were detected biochemically and histologically. The reactive hyperemia of the replanted limb usually occurred after replantation. This rate, however, was significantly decreased after replantation of the amputated limb perfusion with FC. These effects described above were more remarkable when the amputated limb was perfused continuously rather than intermittently. It is therefore reasonable to conclude that for prevention of systemic ill effect after replantation and for preservation of function of the amputated limb, continuous perfusion with FC in ice water is more effective than ice water cooling alone.

Amputation, Traumatic↗
PubMed1983

Application of ACTH stimulation to adrenal imaging with radioiodocholesterol.

ACTH-stimulation adrenal imaging (ACTH-I) was performed in 14 patients after baseline imaging (B-I) was performed. In six patients with no adrenal diseases in whom the findings of B-I were equivocal, morphologic normality of the adrenals was confirmed by ACTH-I because of increased adrenal uptake of radioiodocholesterol. In three patients with cortisol-producing tumors, visualization of contralateral glands by ACTH-I provided indirect evidence for autonomous cortisol secretion of the tumors. In three patients with pheochromocytoma or cyst, ACTH-I increased adjacent cortical radioactivity to more clearly delineate the lesions. In two patients with primary adrenocortical insufficiency, exogenous ACTH had no effect on adrenal uptake of the tracer. Correlation was observed between response of the adrenal net counts and urinary excretion of 17-OHCS and 17-KS. ACTH-I is useful when B-I does not provide sufficient diagnostic information or further information is needed due to low or absent radioiodocholesterol uptake by the adrenal gland(s).

17-Ketosteroids↗
PubMed1983

Use of the immunoperoxidase technique for estimation of susceptibility of herpes simplex virus to IDU.

We applied the direct immunoperoxidase method to estimate the susceptibility to IDU of 17 strains of the virus which were isolated from the patients with active epithelial lesions of herpetic keratitis. All the strains were found to be sensitive below the IDU concentration of 5 micrograms/ml. The findings obtained by this method were in good agreement with those by the fluorescent antibody technique. The present method is specific and simple. It offers clear-cut interpretation and a permanent record of the results.

Drug Resistance, Microbial↗
PubMed1983

Effects of 5-iodo-2'-deoxyuridine on ultrastructural localization of viral antigens in cultured cells infected with herpes simplex virus.

Changes in viral morphology and localization of viral antigens induced by 5-iodo-2'-deoxyuridine (IDU) were studied using herpes simplex virus-infected monolayers of cultured rabbit corneal cells. A direct antibody enzyme method was employed for immunoelectron and light microscopy. There was no significant difference between the control and the IDU groups in the intracellular distribution of antigen up to 2 hours after infection. At 2 hours after infection, intracytoplasmic antigen began to appear in control and IDU-treated cells either in patchy distributions or in association with rough endoplasmic reticulum. Intranuclear staining appeared also at 2 hours after infection as a diffuse fine granular reaction. At 3 hours after infection, the intracytoplasmic reaction became more or less diffuse and there was slightly more cytoplasmic staining in the untreated group. At 6 hours after infection, reaction products increased in the cytoplasm and the nuclei in both groups but IDU-treated cells showed less intracytoplasmic and more intranuclear staining. The nuclear envelope was stained positive in both groups but IDU-treated cells showed a decreased reaction in the cytoplasmic membranous structure and fewer reaction deposits on the cell surface. At 12 and 18 hours after infection, the intranuclear accumulation of reaction products after IDU treatment became more evident. Progeny virus particles were significantly fewer in the presence of IDU: Nucleocapsids were found but in a greatly reduced number and only one incompletely enveloped particle was found. The morphology of the individual nucleocapsid, however, was not significantly altered by treatment with IDU. The preponderance of reaction substances in the nuclei compared to the cytoplasm in treatment groups may reflect distorted protein synthesis and may provide morphological evidence of the biochemical hypothesis of IDU efficacy: IDU exerts its antiviral effects through abnormal protein synthesis and the resultant defects in capsid assembly. Decreased reaction substances in the membranous structures of the cytoplasm may be related to reduced or abnormal production of envelope-associated viral antigens.

Animals↗
PubMed1983

Comparative pharmacological evaluation of oral benzathine penicillin G and phenoxymethyl penicillin potassium in children.

Serum penicillin concentrations and urine excretion rates of oral benzathine penicillin G and phenoxymethyl penicillin potassium were evaluated in children. Mean peak serum concentration of 0.134 microgram/ml of benzathine penicillin G and 1.018 microgram/ml of phenoxymethyl penicillin potassium were measured at 125 and 35 min. The mean half-life times were 1.36 and 0.74 hr, and for area under the curve, the values were 0.34 and 1.68 microgram . hr/ml for benzathine penicillin G and phenoxymethyl penicillin potassium groups, respectively. Phenoxymethyl penicillin potassium had more reliable pharmacokinetic properties and would be the preferred forms of oral penicillin. However, all patients receiving penicillin G had penicillinemia, which was enough to inhibit most strains of Streptococcus pyogenes for a longer period than phenoxymethyl penicillin potassium. Palatability of phenoxymethyl penicillin is less than for benzathine penicillin G; the latter may be used for children in whom compliance may be a problem.

Biological Availability↗
PubMed1983

[Clinical evaluation of cefotetan in pediatrics].

Fifteen children with acute bacterial infections, including pneumonia (8), pharyngitis (2), cervical lymphadenitis (1), perforative peritonitis (1), gastroenteritis (1) and urinary tract infection (2), were treated with cefotetan. This drug was effective to all of the patients. In 2 patients the result was excellent and in 9 it was satisfactory. No adverse reactions were observed in the above cases and 2 other patients, during and after the dosage of 30-60 mg/kg/day for 4-11 days.

Age Factors↗