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Biomedical subjects

T Mimaki

Publications and source records attributed to T Mimaki.

At least 55 records · Page 3Linked to original sources
PubMed1987

Sensitivity to UV radiation of fibroblasts from a Japanese group A xeroderma pigmentosum patient with mild neurological abnormalities.

A 12-year-old girl, suffering from xeroderma pigmentosum (XP), had mild cutaneous and neurological abnormalities. She showed no neurological abnormalities at the age of seven, but areflexia of the patellar tendons at II. She had no malignant tumours. The skin fibroblasts from the patient were about twice as sensitive to the lethal effects of 254 nm ultraviolet (UV) radiation as those of Group C XP patients, and about twice as resistant as those of typical Group A XP patients. The ability of these fibroblasts to reactivate UV-damage adenovirus 5 was intermediate between those of Group C and typical Group A patients. The patient's cells were assigned to genetic complementation Group A by use of the cell-fusion technique. This is the first case in Japan of a Group A XP patient with mild neurological abnormalities. The mild cutaneous manifestations of this patient may be explained by the residual ability of the cells to repair UV-damaged DNA.

Adenoviruses, Human↗
PubMed1986

Neurological manifestations in xeroderma pigmentosum.

Xeroderma pigmentosum is an unusual neurocutaneous disorder. Recent studies have classified patients with xeroderma pigmentosum into 10 groups by somatic cell hybridization methods. In this report we describe 32 patients with Group A xeroderma pigmentosum, including 1 patient with an atypical case, who were assessed for neurological complications. Of these patients, 17 had microcephaly, 13 short stature, and 21 mental retardation. In patients over 7 years of age, sensorineural deafness and spinocerebellar signs such as nystagmus, dysarthria, tremor, and ataxia were frequently observed; no patients below 7 years of age had such neurological complications. Electroencephalographic studies revealed abnormal slow and low voltage background activity. Two patients had focal abnormal discharges, one of whom developed versive seizures. Cranial computed tomographic scans revealed abnormalities, including ventricular dilatation, cerebral atrophy, cerebellar and brainstem atrophy, and cranial bone thickening. A patient with an atypical case of Group A xeroderma pigmentosum had less skin and neurological involvement, and higher levels of postultraviolet colony-forming ability and host cell reactivation than did a typical Group A case. It is possible that these less severe cytological findings are responsible for the less severe skin lesions and neurological complications noted clinically.

Adolescent↗
PubMed1986

Effects of phenobarbital on lipid peroxidation in vitamin-E-deficient rats.

Increased serum lipid peroxide (LPO) and decreased vitamin E (VE) levels have been reported in epileptic children after long-term anticonvulsant therapy. The present study was designed to examine the acute effects of phenobarbital (PB) on lipid peroxidation in VE deficient rats. Five-day treatment with PB (75 mg/kg/day, IP) caused a significant increase in liver LPO levels (P less than 0.01), a decrease in plasma LPO levels (P less than 0.02), and a significant decrease in liver VE levels (P less than 0.05). It is suggested that PB plays an important role in lipid peroxidation in the liver by interfering with VE metabolism.

Animals↗
PubMed1985

Xanthine calculi in the patient with the Lesch-Nyhan syndrome associated with urinary tract infection.

A Japanese boy with Lesch-Nyhan syndrome who passed xanthine calculi is reported. After pyelolithotomy for a left renal stone, made up of ammonium urate, associated with urinary tract infection, a high dose of allopurinol was given because of the persistence of pyuria. In the present case, the administration of a high dose of allopurinol, given for the prevention of ammonium urate stone formation in infected urine, induced xanthine calculi formation and we had difficulty in the management of this patient with Lesch-Nyhan syndrome associated with urinary tract infection. However, we believe it a basic necessity to cure our patient of his urinary tract infection and prevent recurrent ammonium urate stone formation because of the risk of renal deterioration.

Allopurinol↗
PubMed1984

Antiepileptic effect and serum levels of clorazepate on children with refractory seizures.

Clorazepate dipotassium is rapidly decarboxylated to yield desmethyl diazepam. The antiepileptic effect of clorazepate was studied in 29 epileptic children with refractory seizures. Their ages were ranged from one year 9 months to 20 years (mean 11 years 6 months). Serum clorazepate levels were also determined in 16 patients. The mean initial dose was 0.91 mg/kg/day, and the dose was increased up to 3 mg/kg/day. Within several days after initiation of clorazepate therapy, a decrease in seizure frequency was seen in patients in whom clorazepate was effective. Excellent results (decrease in seizure frequency by more than 80%) were obtained in 7 patients (24.1%), a moderate improvement with a 50 to 80% decrease was seen in 7 patients (24.1%), and a partial improvement with less than 50% decrease was seen in 7 patients (24.1%). No benefit was seen in 8 patients (27.7%). Serum clorazepate levels in patients with excellent results were 31 to 77 ng/ml (mean 55 ng/ml), those in patients with a moderate improvement were 130 to 225 ng/ml (mean 163 ng/ml), and those in patients with a partial improvement were 142 to 518 ng/ml (mean 273 ng/ml). Serum clorazepate levels in patients with no benefit were 34 to 97 ng/ml (mean 56 ng/ml). There was no direct relationship between serum clorazepate levels and clinical response. The results of this study indicate the efficacy of clorazepate for epileptic children with refractory seizures.

Adolescent↗
PubMed1984

Effects of seizures and antiepileptic drugs on benzodiazepine receptors in rat brain.

Benzodiazepine receptors appear to be pharmacologically important as the modulator of anxiolytic, anticonvulsant, and muscle relaxant activities in the central nervous system. The acute effects of valproic acid (VPA), diazepam (DZ), phenobarbital (PB), and phenytoin (PHT) on benzodiazepine receptor binding as measured by 3H-flunitrazepam were studied in Sprague Dawley (S/D) rat cerebral cortices. The acute effects of seizures were also studied in both S/D rats and audiogenic seizure rats. In the VPA (100 mg/kg, IP) treated rats, there was a 11% increase in benzodiazepine receptor density (Bmax). This effect appear to be dose dependent as higher doses of VPA (200-500 mg/kg) resulted in more increase in Bmax. No significant change occurred in Kd after acute VPA treatment. However, acute PB (100 mg/kg), PHT (100-200 mg/kg), or DZ (50 mg/kg) did not produce any changes in Bmax or dissociation constants (Kd). In S/D rats, significant increases in Bmax were observed 30 minutes after seizures induced by electroshock or pentylenetetrazol (50 mg/kg) IP injection. However, audiogenic seizure rats had higher Bmax prior to the induction of seizures when compared to normal S/D rats, and no changes in Bmax occurred after seizures in audiogenic seizure rats. No changes in Kd were seen in either S/D rats or audiogenic seizure rats before and after seizures. These data suggest that an increase in benzodiazepine receptor density might correlate with the mechanism of anticonvulsant action of VPA, and that a possible disorder of the GABA/benzodiazepine receptor complex may be involved in the seizure susceptibility in audiogenic seizure rats.

Acoustic Stimulation↗
PubMed1984

A live varicella vaccine in a pediatric community.

A total of 663 children with various underlying diseases were immunized with a live varicella vaccine at the vaccine clinic of Osaka University Hospital during a period of seven years from October, 1975. Clinical reactions after vaccination occurred in 32.4% (24/74) of the children with malignancies and in 0.3% (2/591) of those in other groups. Vaccine-induced immunity was detected for more than 6 years, by FAMA (fluorescent antibody to membrane antigen) and IAHA (immune adherence hemagglutination) tests, and a skin-test for varicella-zoster virus (VZV). During an observation period of more than 7 years, clinical varicella developed in 12 children, 8 of whom were in the group with malignancies. Zoster occurred in only 4 (9.1%) of 44 vaccinees with acute leukemia, this incidence being significantly less (p less than 0.05) than that (21.6%, 8/37) in un-vaccinated leukemic children.

Antibodies, Viral↗