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Biomedical subjects

N Matsuo

Publications and source records attributed to N Matsuo.

At least 289 records · Page 16Linked to original sources
PubMed1989

[Effects of atrial natriuretic factor on the cardiovascular system and several parameters of renal excretory function in spontaneously hypertensive rats].

The influence of atrial natriuretic factor on several parameters of cardiovascular system and renal excretory function in spontaneously hypertensive rats has been investigated. The exogenously administered atrial natriuretic factor, not influencing the arterial pressure level and electrolyte concentration in the urine, at the same time breaks the links between APmax and the intensity of electrolyte excretion in urine.

Animals↗
PubMed1988

Accurate measurement of psoralen-crosslinked DNA: direct biochemical measurements and indirect measurement by hybridization.

This paper evaluates methods to measure crosslinkage due to psoralen plus light in total DNA and in specific sequences. DNA exposed in cells or in vitro to a bifunctional psoralen and near ultraviolet light accumulates interstrand crosslinks. Crosslinkage is the DNA mass fraction that is attached in both strands to a crosslink. We show here biochemical methods to measure psoralen photocrosslinkage accurately in total DNA. We also describe methods to measure photocrosslinkage indirectly, in specific sequences, by nucleic acid hybridization. We show that a single 4,5',8-trimethylpsoralen (TMP) crosslink causes at least 50 kbp of alkali-denatured DNA contiguous in both strands with it to snap back into the duplex form when the denatured preparation is returned to neutral pH. This process was so efficient that the DNA was not nicked by the single-strand nuclease S1 at 100-fold excess after snapping back. Uncrosslinked DNA was digested to acid-soluble material by the enzyme. Crosslinkage therefore equals the fraction of S1-resistant nucleotide in this kind of experiment. We alkali-denatured DNA samples crosslinked to varying degrees by varying TMP concentration at constant light exposure. We then measured crosslinkage by ethidium bromide (EtBr) fluorometry at pH 11.8; by EtBr fluorometry at neutral pH of S1 digests of the DNA; and by the fraction of radioactivity remaining acid insoluble in S1-digests of DNA labeled uniformly with [3H]deoxythymidine. These assays measure distinct physical properties of crosslinked DNA. Numerical agreement is expected only when all three measurements are accurate. Under optimum conditions, the three methods yielded identical results over the range of measurement. Using alkaline EtBr fluorescence in crude cell lysates, we detected crosslinks at frequencies in the range of 1.6 X 10(-7) per base pair. These levels were compatible with cell survival, attesting to the sensitivity of the measurement system. Crosslinkage affected hybridization as well. One crosslink prevented all alkali-denatured DNA contiguous in both strands with it from hybridizing to complementary DNA either on solid supports or in solution. Strand-length effects on crosslinkage and on reassociation caused solution hybridization levels to exceed those predicted by simple theory. In a quantitative, dot-blotting assay hybridization was linear up to membrane saturation by denatured, uncrosslinked DNA of any strand length.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1988

A proposed mild type of acute retinal necrosis syndrome.

Six patients had peripheral to midperipheral pale yellow retinal exudates typical of acute retinal necrosis syndrome but which extended gradually to the posterior pole and remained isolated without becoming confluent. These exudates resulted in localized retinochoroidal degeneration without retinal detachment, in contrast to acute retinal necrosis syndrome. Antibody titers in aqueous humor were increased to varicella-zoster virus in some of the patients examined. The findings led us to hypothesize that this mild, self-limiting course is one of the natural developments of acute retinal necrosis syndrome, although somewhat modified by corticosteroid or acyclovir therapy, and that acute retinal necrosis syndrome consists of varying degrees of severity from mild to fulminant types.

Acute Disease↗
PubMed1988

Inhibition of post-decapitation convulsions in the rat by dibenzothiepin neuroleptics via alpha 1-adrenoceptor blockade.

The mechanisms involved in inhibitory effects of isofloxythepin, a newly synthesized dibenzothiepin neuroleptic, on post-decapitation convulsions were studied in rats. Isofloxythepin (0.05-2.0 mg/kg s.c.) inhibited post-decapitation convulsions in a dose-dependent manner as shown by the decrease in the incidence and the shortening of the duration of convulsions. The convulsions were also inhibited by oxyprothepin, zotepine or chlorpromazine but not by haloperidol. Prazosin and bunazosin, both alpha 1-adrenoceptor antagonists, suppressed the post-decapitation convulsions but a non-selective alpha 2-adrenoceptor agonist, tolazoline, was without effect. The convulsions were inhibited dose dependently by clonidine, an alpha 2-adrenoceptor agonist, but were prolonged in duration by yohimbine, an alpha 2-adrenoceptor antagonist. Yohimbine antagonized the inhibitory effects of isofloxythepin, prazosin and clonidine. The noradrenaline-induced contraction of rat vas deferens was inhibited by isofloxythepin, prazosin or chlorpromazine. Isofloxythepin bound to alpha 1-receptors as did chlorpromazine in the rat brain cortex. The results imply that post-decapitation convulsions seem to be inhibited by a block of postsynaptic alpha 1-adrenoceptors, enhanced by a block of presynaptic alpha 2-adrenoceptors and reduced by isofloxythepin via the blocking of postsynaptic alpha 1-adrenoceptors. The convulsions thus could serve as a good model for studying the actions of drugs on the central nervous system alpha-adrenoceptors.

Adrenergic alpha-Agonists↗
PubMed1988

Computed tomography in the early detection of congenital lipoid adrenal hyperplasia.

This paper describes the successful use of abdominal computed tomography (CT) scan in diagnosing congenital lipoid adrenal hyperplasia in a Japanese male with no virilization at 9 days of age. The CT unequivocally delineated massively enlarged adrenal glands of fat-tissue attenuation, enabling early replacement therapy.

Adrenal Hyperplasia, Congenital↗
PubMed1988

Effects of isofloxythepin enantiomers on prolactin secretion and postdecapitation convulsions in rats.

Racemic isofloxythepin and its enantiomers (0.05-1.0 mg/kg) administered subcutaneously increased serum prolactin levels in a dose-dependent manner in rats. The potencies of the drugs were equal for this variable. They (0.05-1.0 mg/kg, SC) also decreased dose-dependently the incidence and duration of postdecapitation convulsions, the convulsions being abolished at 1.0 mg/kg in all groups. Although (-)-enantiomer had slightly stronger effects than those of raceme and (+)-enantiomer, there were no great differences in their inhibitory effects on postdecapitation convulsions. The results indicate that isofloxythepin enantiomers in addition to raceme increase serum prolactin levels and inhibit postdecapitation convulsions and that they seem to have similar potency in blocking of dopamine receptors and alpha 1-adrenoceptors.

Animals↗
PubMed1988

Computed tomography detection of small daughter nodules in hepatocellular carcinoma after iodized oil infusion into the hepatic artery.

The detectability of small daughter nodules of hepatocellular carcinoma by computed tomography after hepatic arterial infusion of Lipiodol (iodized oil) and by infusion hepatic angiography was studied in 102 cases. The Lipiodol was selectively accumulated by the tumor. Tumors and small daughter nodules appeared as high-density areas on computed tomography. In 24 cases daughter nodules were identified only by computed tomography. In 50 cases computed tomography demonstrated superior ability to detect the daughter nodules when compared with infusion hepatic angiography. In 21 cases the daughter nodules were detected for the first time in areas other than the main site of the primary tumor. Lipiodol-computed tomography is very effective in the diagnosis of daughter nodules of hepatocellular carcinoma.

Angiography↗
PubMed1988

Effect of Ca2+ deprivation on short-term desensitization of isolated smooth muscle cells showing an all-or-none response to acetylcholine.

1. Short-term desensitization of the contractile response of isolated smooth muscle cells from guinea pig taenia caecum to acetylcholine was examined in the absence of external Ca2+. 2. Isolated smooth muscle cells contracted to 10(-7)-10(-6) M acetylcholine, showing an all-or-none response. 3. Desensitization was induced by incubating the cells with 10(-4) M acetylcholine for 10 min in Ca2+-free solution. 4. Desensitized cells showed an all-or-none response but required a higher concentration of acetylcholine for induction of contraction, indicating that the desensitization was due to a change in the threshold concentration. 5. Desensitization is suggested to be induced before massive influx of Ca2+ into the cells.

Acetylcholine↗
PubMed1988

Unusual clear regenerative nodules of the liver with accumulation of orcein and victoria blue-positive granules.

An unusual nodular transformation of the liver was found in a 53-year-old man with meningoencephalitis who died of brain stem herniation. Postmortem examination revealed marked neuronal ischemic changes and bronchopneumonia as well as meningoencephalitis. The liver showed no significant lesions macroscopically. Histologically, there were many small nodules, less than 1 mm in diameter and composed of clear hepatocytes, throughout the liver. The liver cells in these nodules showed mild hyperplastic changes. Many fine granules, stained by orcein and Victoria blue, were found exclusively in the hepatocytes of these nodules. We describe the peculiar histopathology of this case with reference to some related lesions.

Carrier Proteins↗
PubMed1988

Proximal renal tubular acidosis associated with glycogen storage disease, type 9.

A 2 1/2-year-old Japanese boy with glycogen storage disease, type 9, developed proximal renal tubular acidosis (RTA). The RTA significantly improved in response to cornstarch therapy, implying a direct causal relationship between subtle metabolic derangements in glycogen storage disease, type 9, and proximal RTA.

Acidosis, Renal Tubular↗
PubMed1988

Effects of minaprine, a novel antidepressant, on prolactin secretion in the rat.

The effect of minaprine, a novel psychotropic drug with antidepressant properties, on prolactin secretion has been investigated in the rat. On intraperitoneal administration (10 and 20 mg kg-1) it significantly decreased basal prolactin levels. In contrast, both haloperidol (1 mg kg-1 i.p.) and morphine (20 mg kg-1 i.p.) increased serum prolactin levels and daily treatment with oestradiol (100 micrograms kg-1 s.c.) for 4 days also elevated the levels. Minaprine at a dose of 20 mg kg-1 failed to antagonize the elevation of serum prolactin levels induced by these drugs. The results imply that minaprine may not exert a direct inhibitory action on prolactin secretion at the pituitary gland.

Animals↗
PubMed1988

Keratomalacia in a child with familial hypo-retinol-binding proteinemia.

Retinol-binding protein (RBP) is a plasma protein with a molecular weight of 21,000 synthesized in the hepatocytes, binding with retinol (vitamin A), and transporting retinol to peripheral tissues. Keratomalacia is caused by a deficiency of vitamin A itself and/or protein-calorie malnutrition. In the latter condition, production of RBP is inhibited. We report herein familial hypo-retinol-binding proteinemia in a child aged 19 months who developed keratomalacia during measles infection in spite of good nourishment. To the best of our knowledge this is the first description of such a case. The patient, her sister and mother showed persistent low levels, about half the normal levels, of retinol and RBP which were unresponsive to oral vitamin A and protein-rich diet. They had normal liver function tests, normal serum levels of other proteins and fat-soluble vitamins and lipids. This hypo-retinol-binding proteinemia was thought to predispose the child to develop keratomalacia during measles. Family members would be heterozygous with one normal RBP gene and one defective RBP gene.

Child↗