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Biomedical subjects

Y Uchida

Publications and source records attributed to Y Uchida.

At least 667 records · Page 37Linked to original sources

Prophylactic effect of neuroleptics in symptom-free schizophrenics: a comparative dose-response study of haloperidol and propericiazine.

Remitted schizophrenic outpatients were treated in order to prevent relapse with three doses of haloperidol or propericiazine for 1 year in a double-blind controlled study employing a randomized design. The drug's ability to prevent relapse was evaluated by counting the number of symptom-free days for each patient before any sign of relapse or over-dose appeared. Patients were randomly assigned to the following drugs orally administered once per day at night: placebo; haloperidol 1 mg, 3 mg, and 6 mg; propericiazine 10 mg, 30 mg, and 60 mg. Serum prolactin levels in each patient were estimated by radioimmunoassay. All patients treated with placebo relapsed within 1 year and the relapse rate with placebo was significantly higher than with any dose of the two neuroleptics. Haloperidol increased the number of symptom-free days in a dose-dependent manner. Propericiazine at 10 mg and 30 mg also increased the number of symptom-free days dose-dependently but at 60 mg, the number decreased. It appears that propericiazine shows an inverted U-shaped dose-response curve. Prolactin levels were elevated dose-dependently by both drugs but failed to show a significant correlation with the number of symptom-free days. The present results indicate that haloperidol is superior to propericiazine from the viewpoint of the wider "therapeutic window" in maintenance treatment and antidopaminergic properties of neuroleptics, wherein it is important to prevent relapse even in remitted schizophrenics.

Adult↗

Reduction of prostacyclin synthesis as a possible cause of transient flow reduction in a partially constricted canine coronary artery.

Coronary blood flow decreases cyclically in a partially occluded coronary artery of anesthetized dogs. Spontaneous aggregation and deaggregation of platelet plugs in the constricted artery have been indicated to be responsible for this phenomenon. A current hypothesis is that platelet aggregation may be determined by a balance between proaggregatory platelet product, thromboxane A2 (TXA2), and antiaggregatory substance, prostacyclin (PGI2). To elucidate the relationship between the cyclical reduction of coronary flow (CRCF) and metabolic alterations of TXA2 and PGI2, we attempted to determine the plasma levels of their stable catabolites, thromboxane B2 (TXB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), in the coronary circulation of 69 dogs. Of 40 cases, 20 cases exhibited CRCF accompanying a significant increase in TXB2 in the coronary sinus (CS) (P less than 0.05) and constant levels of 6-keto-PGF1 alpha in the CS and aorta (Ao). Another 20 cases did not exhibit CRCF that accompanied a marked increase in 6-keto-PGF1 alpha (P less than 0.05) with virtually no change in TXB2 in the CS and Ao. A higher dose of indomethacin (10 mg/kg, i.v.) was capable of evoking CRCF in cases not exhibiting CRCF spontaneously. Under these conditions, a significant decrease in 6-keto-PGF1 alpha was seen both in the CS and Ao compared with lower doses of indomethacin (1 to 3 mg/kg, P less than 0.01), that produced less pronounced reduction of 6-keto-PGF1 alpha without CRCF. Intravenous infusion of PGI2 (0.1 microgram/kg/min.) completely abolished spontaneously and indomethacin-induced CRCF with a marked elevation of 6-keto-PGF1 alpha in the CS and Ao. Although OKY-1580, a TXA2 synthetase inhibitor, relieved spontaneously-evoked CRCF with a marked increase in 6-keto-PGF1 alpha and a slight reduction of TXB2, indomethacin-induced CRCF was not abolished by this agent. These results are consistent with the hypothesis that the reduction of endogenous PGI2 synthesis in the vascular wall is related to the occurrence of CRCF after partial constriction of coronary artery and indomethacin.

6-Ketoprostaglandin F1 alpha↗

Pathophysiology of positional vertigo of the malignant paroxysmal type.

It is well known that paroxysmal positional vertigo is induced by change of head position and subsides immediately when the head is returned to the original position. There are two types of paroxysmal positional vertigo. One is what DIX and HALLPIKE (1952) call the benign type which is thought to be caused by otolith lesions. Another is a malignant type, in contrast to the former and is related to a lesion in the central nervous system. Otologists are usually familiar with the former, but the latter is not known among neurologists and neurosurgeons. We experienced 37 cases of the malignant type and found that this type of paroxysmal vertigo is induced by various diseases. Furthermore, we believe that the mechanism of this paroxysmal vertigo is the lack of inhibitory function of the vestibular cerebellum, and not abrupt malfunction of communication of the cerebrospinal fluid in the ventricular system. We also believe that this symptom is a very useful sign for diagnosing lesions of the cerebellar vermis.

Adult↗

Purification and properties of N-acetylneuraminate lyase from Escherichia coli.

N-Acetylneuraminate lyase [N-acetylneuraminic acid aldolase EC 4.1.3.3] from Escherichia coli was purified by protamine sulfate treatment, fractionation with ammonium sulfate, column chromatography on DEAE-Sephacel, gel filtration on Ultrogel AcA 44, and preparative polyacrylamide gel electrophoresis. The purified enzyme preparation was homogeneous on analytical polyacrylamide gel electrophoresis, and was free from contaminating enzymes including NADH oxidase and NADH dehydrogenase. The enzyme catalyzed the cleavage of N-acetylneuraminic acid to N-acetylmannosamine and pyruvate in a reversible reaction. Both cleavage and synthesis of N-acetylneuraminic acid had the same pH optimum around 7.7. The enzyme was stable between pH 6.0 to 9.0, and was thermostable up to 60 degrees C. The thermal stability increased up to 75 degrees C in the presence of pyruvate. No metal ion was required for the enzyme activity, but heavy metal ions such as Ag+ and Hg2+ were potent inhibitors. Oxidizing agents such as N-bromosuccinimide, iodine, and hydrogen peroxide, and SH-inhibitors such as p-chloromercuribenzoic acid and mercuric chloride were also potent inhibitors. The Km values for N-acetylneuraminic acid and N-glycolylneuraminic acid were 3.6 mM and 4.3 mM, respectively. Pyruvate inhibited the cleavage reaction competitively; Ki was calculated to be 1.0 mM. In the condensation reaction, N-acetylglucosamine, N-acetylgalactosamine, glucosamine, and galactosamine could not replace N-acetylmannosamine as substrate, and phosphoenolpyruvate, lactate, beta-hydroxypyruvate, and other pyruvate derivatives could not replace pyruvate as substrate. The molecular weight of the native enzyme was estimated to be 98,000 by gel filtration methods. After denaturation in sodium dodecyl sulfate or in 6 M guanidine-HCl, the molecular weight was reduced to 33,000, indicating the existence of 3 identical subunits. The enzyme could be used for the enzymatic determination of sialic acid; reaction conditions were devised for determining the bound form of sialic acid by coupling neuraminidase from Arthrobacter ureafaciens, lactate dehydrogenase, and NADH.

Escherichia coli↗

Clonidine therapy for tardive dyskinesia and related syndromes.

Twenty-nine patients with tardive dyskinesia (n = 20) or related syndromes [spontaneous dyskinesia (n = 3), levodopa-induced dyskinesia (n = 3), tardive dystonia (n = 3)] were treated with clonidine. Clinical effects of this drug were observed for up to 4 years. Seventy-five percent of patients showed at least moderate improvement, and in 50% of patients, full resolution occurred. In most cases, patients received concomitant medications, including neuroleptics and benzodiazepines. Two patients received clonidine alone, and dyskinesia was only minimally improved; however, when bromocriptine was added, prompt improvement occurred on this combined regimen. On the basis of these findings, we suggest that not only receptor supersensitivity of dopaminergic neurons but also involvement of noradrenergic neurons is important in the pathophysiology of tardive dyskinesia and related syndromes.

Adult↗

Chronic granulomatous disease of childhood and sea-blue histiocytosis. A pathologic study of an autopsy case.

A boy, who started remittent fever reaching 40 degrees C at the age of 4 years and 9 months and gradually developed hepatosplenomegaly, lymphadenopathy, pancytopenia, and hypergammaglobulinemia, is reported. Aspirated bone marrows contained sea-blue histiocytes, and nitroblue tetrazolium test was abnormal. X-ray examination revealed a tumor mass in the right lung, uremia occurred terminally, and he died at the age of 10 years and 3 months. Surgical specimens, obtained by splenectomy, and necropsy revealed the presence of characteristic sea-blue cells in the bone marrow, spleen, lymph nodes, liver, and kidneys, and pseudotuberculous granulomas with or without aspergillus in the lungs, epicardium, liver, and lymph nodes. Histochemically, sea-blue granules accumulating in the cytoplasm of the histiocytes were proved to be a lipogenic ceroid-like pigment. Electron microscopically, these granules were comprised of round or ovoid, membrane-bound or free lipid droplets of various sizes and electron densities, occasionally containing poorly oriented, lamellar structures. The nature and possible pathogenesis of the sea-blue histiocytosis in this case are discussed briefly.

Autopsy↗

Corneal findings in a foetus with Fabry's disease.

The cornea of a 22-week foetus with Fabry's disease was examined biochemically and histopathologically. The alpha-galactosidase activity in the cornea was very low compared with that of the normal control. Histopathologic examination revealed that intracytoplasmic lamellar bodies surrounded by a single membrane were present in the epithelial cells. The lamellar bodies were thought to result from the abnormal accumulation of ceramide trihexoside. We conclude that ceramide trihexoside already has begun to accumulate progressively in the epithelial cells in the mid-trimester of gestation.

Adult↗