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Biomedical subjects

I Matsui

Publications and source records attributed to I Matsui.

At least 91 records · Page 5Linked to original sources

A new malformation syndrome of long palpebral fissures, large ears, depressed nasal tip, and skeletal anomalies associated with postnatal dwarfism and mental retardation.

Five unrelated patients with a previously unrecognized mental retardation malformation syndrome are presented. Clinical features common to them include moderate mental retardation, postnatal dwarfism, susceptibility to infection in infancy, and peculiar craniofacial dysmorphia characterized by long palpebral fissures, high-arched and abnormal eyebrows, heavy and long eyelashes, large ears, short nasal septum and/or depressed nasal tip, and cleft palate. Other anomalies are stubby fingers, deformed vertebra and other bone and joint anomalies, and abnormal dermatoglyphics. The absence of familial occurrence and of consanguinity suggests some environmental causation, but the possibility of an autosomal dominant or X-linked mode of inheritance remains. Based upon our five patients and other five of Niikawa et al, we propose this syndrome as a new disease entity.

Abnormalities, Multiple↗

Dermatoglyphics in typical cleft hand.

Dermatoglyphic prints of the typical cleft hand with a rudiment of the middle metacarpal showed that a whorl pattern was present on the ulnar margin of the V-shaped defect, suggesting the fingertip pattern of the middle finger.

Adolescent↗

Mortality and survival for Down syndrome in Japan.

Mortality and survival data for 1,052 Japanese patients with Down syndrome who were born between 1966 and 1975 were analyzed. The survival rate at age 10 was estimated to be about 86%. Mortality in each age group for Down syndrome was elevated over that of the general population. In the survival rate at age 10, there was no significant difference between males and females, but the difference between cases with and without congenital heart disease was highly significant. Using data from this study-for mortality up to age 10-and from the study of institutionalized cases for mortality over age 10, a hypothetical life table was constructed; it shows that the life expectancy at birth for cases with Down syndrome is nearly 50 years.

Adolescent↗

Formation of putrescine in rat liver.

Two pathways exist for the formation of putrescine in rat liver. Putrescine can be produced by the action of L-ornithine decarboxylase, an inducible enzyme which can be irreversibly inhibited by the drug, alpha-difluoromethylornithine. A method for quantitating the amount of active ornithine decarboxylase protein present in the liver under various conditions by measuring the binding of [5-14C]alpha-difluoromethylornithine is described. The results indicated that, even when maximally induced, less than 0.0002% of the liver cytosol protein is ornithine decarboxylase. A second pathway for the production of putrescine occurs in the liver by means of the acetylation of spermidine to N1-acetylspermidine and its oxidation to putrescine and N-acetyl-3-aminopropionaldehyde by polyamine oxidase. This pathway is controlled by the activity of spermidine N1-acetyltransferase which is induced by hepatotoxins. Both ornithine decarboxylase and spermidine N1-acetyltransferase turn over rapidly as indicated by the loss of activity in response to cycloheximide. Following treatment with either carbon tetrachloride or thioacetamide, changes in spermidine N1-acetyltransferase activity precede those in ornithine decarboxylase and experiments with appropriate inhibitors indicate that the early enhancement of hepatic putrescine levels if brought about by the acetylase/oxidase pathway. Subsequently, enhanced ornithine decarboxylase activity maintains the putrescine levels and restores the depleted spermidine content of the liver.

Acetyltransferases↗

Effect of thioacetamide, growth hormone or partial hepatectomy on spermidine acetylase activity of rat liver cytosol.

Rat liver cytosol extracts catalyzed the formation of monoacetylspermidine when incubated with acetyl-CoA and spermidine. This activity was enhanced 15-fold by administration of thioacetamide (150 mg/kg). The peak of activity occurred 18-24 h after treatment with the drug and then declined reaching control levels by 76 h. Previous studies have shown that ornithine decarboxylase activity was also greatly increased over this time period. Putrescine content in the liver was increased 80-90-fold at 18-24 h and then declined. Spermidine levels were decreased significantly over the period 12-24 h after thioacetamide treatment and then increased substantially at later times. These results are consistent with the hypothesis that, at early times after administration of thioacetamide, the increase in putrescine content is brought about both by decarboxylation of ornithine and by degradation of monoacetylspermidine. Spermidine acetylase activity was also measured in liver extracts prepared after two other physiological stimuli known to enhance ornithine decarboxylase activity were used. Both growth hormone treatment and partial hepatectomy produced an early 2-3-fold increase in the cytosolic spermidine acetylase activity.

Acetamides↗

The "happy puppet" syndrome in two siblings.

Two siblings with the "happy puppet" syndrome are presented. Their clinical features are quite similar and closely resemble those of previously reported cases. These features include severe mental retardation, epileptic seizures, easily provoked and prolonged paroxysms of laughter, atactic jerky movements, hypotonia, large mandible with prognathia, and 2-3 cps spike and wave activity in the EEG. The occurrence of this syndrome in the two siblings suggests a genetic etiology possible as an autosomal recessive trait.

Child↗

Effect of urethan on polyamine and DNA synthesis in the regenerating rat liver.

When a single dose of urethan was injected into the peritoneal cavity of rats immediately after partial hepatectomy, DNA synthesis was delayed by 12 h. The induction of ornithine decarboxylase which was induced biphasically following partial hepatectomy was also reduced and delayed by 14-15 h by the administration of urethan. S-Adenosylmethionine decarboxylase activity in urethan-treated rat liver at 20 h and 29 h after operation was significantly lower than that of untreated animals. This enzyme activity was shown to increase thereafter, reaching a higher level than in untreated rats at 37-42 h. Hepatic spermidine content changed biphasically in a manner similar to DNA synthesis. These results suggest that the activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase may correlate with DNA synthesis and that an increase of spermidine concentration is necessary to DNA synthesis.

Adenosylmethionine Decarboxylase↗

Effect of urethan on the induction of ornithine decarboxylase in regenerating rat liver.

The effect of urethan on the induction of ornithine decarboxylase in the early stage of the regeneration of rat liver was studied. The induced activity of ornithine decarboxylase was suppressed by administration of urethan immediately after partial hepatectomy. Although ornithine decarboxylase was induced biphasically by partial hepatectomy, a single intraperitoneal injection of urethan resulted in the reduction of both phases. However, the ornithine decarboxylase activity induced by glucocorticoids and growth hormone was not suppressed by urethan. The increased level of 3',5'-cyclic adenosine monophosphate induced by partial hepatectomy was also reduced by urethan and this suppression was proportional to the suppression of ornithine decarboxylase activity. Reversal of the urethan-induced suppression of ornithine decarboxylase by administration of dibutyryl 3',5'-cyclic adenosine monophosphate was also observed.

Animals↗