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Biomedical subjects

H Nishimura

Publications and source records attributed to H Nishimura.

At least 901 records · Page 50Linked to original sources
PubMed1979

Modification of yeast uricase with polyethylene glycol: disappearance of binding ability towards anti-uricase serum.

Uricase from Candida utilis was modified with activated polyethylene glycol (2-O-methoxypolyethylene glycol-4,6-dichloro-s-triazine) of molecular weight of 5,000 daltons. The modification of 43% of the total amino groups in the uricase molecule gave rise to a complete loss of the binding ability towards anti-uricase serum from rabbit. This modified uricase retained 15% of the enzymic activity of non-modified uricase.

Animals↗
PubMed1978

Primary reconstruction by modified cervical island skin flap following resection of oral and pharyngeal cancer.

Reconstruction of the intraoral defect following cancer surgery often causes formation of fistula, impairment of lingual movement, and prolonged hospitalization by secondary reconstruction. To reduce such complications, the modified cervical island skin flap method as a one-stage intraoral reconstruction was used in 18 patients. Lateral cervical island flap was used in 15 cases and the median flap in three. This method proved to be successful for 17 patients. One patient who received a preoperative full dose of irradiation developed a fistula. There were two types of healing of the skin flap. The postoperative external appearance and function of the tongue were commendable.

Carcinoma, Squamous Cell↗
PubMed1978

Complete necrotization of hepatocellular carcinoma by chemotherapy and subsequent intravascular coagulation: a case report.

A 45-year-old man with hepatocellular carcinoma who developed intravascular coagulation following complete tumor regression by chemotherapy is described. After 2 doses of 10 mg of Mitomycin C given into the hepatic artery at the time of selective angiography, and 16 intravenous doses of 5-fluorouracil and Mitomycin C, 2 doses per week, subjective symptoms and hepatomegaly disappeared. Alpha-fetoprotein became negative and a remarkable change in tumor size and vasculature was noted in the arteriogram. Three months after chemotherapy, the patient developed thrombocytopenia, intravascular hemolysis, and acute renal failure. Autopsy disclosed a 8 X 7 X 5 cm solitary, encapsulated hepatocellular carcinoma in the right lobe. The tumor was surrounded by a thick capsule and completely necrotized. Neither intrahepatic invasion nor extrahepatic metastasis was observed. In the kidney, generalized fibrin thrombi were seen in the afferent arterioles of glomeruli as accounted for by intravascular coagulation.

Acute Kidney Injury↗
PubMed1978

Studies on 1-substituted 4-(1,2-diphenylethyl)piperazine derivatives and their analgesic activities. 2. Structure-activity relationships of 1-cycloalkyl-4-(1,2-diphenylethyl)piperazines.

Forty-six 1-cycloalkyl-4-(1,2-diphenylethyl)piperazines were synthesized. The influence of substituents on phenyl groups of 1-cycloalkyl-4-(1,2-diphenylethyl)piperazines 4a-c on the analgesic activity was investigated in experimental animals. The most active compounds, 5a-c, in this series had a m-hydroxyl group on the 2-phenyl group of 4a-c, while morphine has a phenolic hydroxyl group para to th- aminoethyl moiety. Their activities were 23-56 and 23-38 times those of their original compounds 4a-c and morphine, respectively, tested by the D'Amour-Smith method after subcutaneous administration.

Analgesics↗
PubMed1978

Lack of specific inhibition of angiotensin II in eels by angiotensin antagonists.

Synthetic angiotensins I and II (AI and AII) and natural eel angiotensin were injected with angiotensin antagonists into freshwater-adapted, unanesthetized American eels, Anguilla rostrata, in an attempt to characterize the vasopressor properties of angiotensins in a primitive vertebrate. A converting enzyme inhibitor, SQ 20,881, inhibited vasopressor responses to eel angiotensin (presumably AI) and [Val5,Ser9]AI, but not those to [Asn1,Val5]AII, suggesting that a converting enzyme-like substance may exist in eels. [Sar1,Thr8]AII (10 microgram/kg per min) and [Sar1,Ile8]AII (1 microgram/kg per min), which antagonize angiotensin's action in mammals, showed neither agonistic vasopressor nor antagonistic effects in eels against [Asn1,Val5]AII or eel angiotensin. [Tal8]AII ([8-thienylalanine]AII) and a higher dose of [Sar1,Ile8]AII increased eel aortic pressure themselves and reduced vasopressor responses to [Asn1,Val5]AII. This is presumably a nonspecific decrease in response during the agonistic phase of the analogs. Angiotensin receptors in the blood vessels of eels may differ from those in mammals. Alpha-adrenergic blocking drugs and reserpine partially inhibited the pressor effect of [Asn1,Val5]AII in eels.

Angiotensin I↗
PubMed1978

Controlled locomotion in the mesencephalic cat: distribution of facilitatory and inhibitory regions within pontine tegmentum.

1. The contribution of postural tonus to controlled locomotion elicited by the stimulation of mesencephalic locomotor region (MLR) was studied in the acute precolicular-postmammillary decerebrate (mesencephalic) cat. 2. A microelectrode was placed in the unilateral MLR and another was placed systematically at 1-mm increments throughout the pons (H--4 to H--1O) at level ranging from P2 to P11 dorsoventrally and mediolaterally from 0 to L or R6. Depending on the general condition of the animal, stimuli through this second electrode were delivered preceding, succeeding, or simultaneous with the MLR stimulation. 3. Stimulation of the ventral part of the caudal tegmental field (P3 to P9, H--6 to H--8) increased extensor tonus of the hindlimbs, as assessed by recording muscle activity. Concomitant stimulation of this region converted MLR-elicited hindlimb stepping to coordinated four-legged locomotion and also elicited locomotion even when stimulation of the MLR alone failed to elicit locomotion. Stimulation of this ventral tegmental region alone at a larger stimulus intensity elicited spastic locomotor movements associated with a substantial increase in extensor tonus. 4. Stimulation of the lateral tegmented field surrounding the pontine locomotor region (PLR) also facilitated MLR effects, but had a relatively weaker facilitatory effect on postural tonus then stimulation of the ventrocaudal tegmental field. PLR stimulation alone was also ineffective when postural tonus was not well maintained. 5 Stimulation of the dorsal part of caudal tegmental field (P3 to P9, H--4 to H--6) in its midline dramatically decreased extensor tonus of the hindlimbs. MLR-elicited controlled locomotion was completely suppressed during concomitant stimulation of this inhibitory region. 6. These results indicated clearly that the degree of existing postural tonus greatly affects MLR-elicited locomotor movements and that an increase in postural tonus and an activation of the spinal stepping generator are not separate phenomenia.

Animals↗
PubMed1978

Physiological evolution of the renin-angiotensin system.

The renin-angiotensin system (RAS) in mammals may participate in the controls of blood pressure and aldosterone secretion, and possibly in the regulation of renal function. It has been shown that renin release is controlled by:1) two intrarenal receptors, the renal arteriolar receptor and the macula densa; 2) the sympathetic nervous system; and 3) several humoral agents. Recent studies indicate interrelations between the RAS and renal prostaglandins and the kallikrein-kinin system. Comparative studies have revealed that renal renin and the juxtaglomerular (JG) cells emerged during the early evolution of bony fishes, wherease the macula densa evolved later in the vertebrate phylogney. Exogenously administered angiotensins and renin produce vasopressor actions in representative species of all vertebrate classes from elasmobranchs to mammals, and increase secreations of mineralocorticoids from the adrenal cortex (interrenal) in amphibians, repitles, and possibly in teleosts. Angiotensin causes glomerular diuresis in teleosts and lung-fishes, which may be ascribed to increased dorsal aortic pressure, while angiotensin may have both glomerular and tubular actions in some amphibians. Intracranial injection of angiotensin stimulates drinking in teleosts, repites, and birds, but not in amphibians. Hemorrage and acute hypotension are potent stimuli for causing renin release in an aglomerular teleost and a bird. When we consider this fact together with the anatomical evidence that the evolution of the JG cells precedes that of the macula densa, it appears that the RAS HAS EVOLVED WITH A CLOSE RELATIONSHIP TO BLOOD PRESSURE HOEMOSTASIS. On the other hand, there is no clear evidence that the RAS is activated in depleted teleosts and amphibians. Although the RAS appears to exert several functions in man and other mammals, some of them may be more important in primitive animals, while a similar function remains in mammals as a relic of the primitive system. Comparative approaches provide a perspective of biological history and unique experimental model that will eventually aid in understanding of the underlying mechanisms operating in mammals.

Adrenal Cortex Hormones↗