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Biomedical subjects

H Okazaki

Publications and source records attributed to H Okazaki.

At least 361 records · Page 20Linked to original sources
PubMed1981

Comparative effects of three calcium antagonists, diltiazem, verapamil and nifedipine, on the sinoatrial and atrioventricular nodes. Experimental and clinical studies.

Diltiazem, verapamil and nifedipine suppress sinoatrial (SA) nodal function in the excised rabbit heart. Clinically, however, their suppressive effect on the SA node is modified considerably by the reflex increase in sympathetic tone as a result of the fall in blood pressure caused by the vasodilating action of the calcium antagonists. Diltiazem, verapamil and nifedipine suppress atrioventricular (AV) nodal conduction and prolong refractory periods in the excised rabbit AV node. Clinically, diltiazem and verapamil exert a similar suppressive effect on the AV node and are useful for treating and preventing AV nodal reentrant tachycardia. Nifedipine, in clinically practical doses, has no antiarrhythmic properties, probably because of reflex activation of the sympathetic system secondary to its hypotensive effect, which is greater than that of the other two calcium antagonists. Diltiazem and verapamil may sometimes worsen AV conduction, especially in patients with conduction disturbances. Nifedipine, on the other hand, can be used as a coronary vasodilator with the least untoward effect on AV conduction.

Adolescent↗
PubMed1981

The splanchnic autonomic outflow in amyloid neuropathy and Tangier disease.

The splanchnic outflow is important in the maintenance of postural normotension in humans. Pathology of outflow is usually associated with postural hypotension. Morphometric analyses were performed on the intermediolateral column neuron cell bodies at the T7 level in four cases of amyloid neuropathy and one case of Tangier disease. In amyloid neuropathy, postural hypotension is common; cell counts were reduced and ranged from 50 to 79% of control values. In Tangier disease, postural hypotension has not been reported; cell counts were normal.

Adult↗
PubMed1981

Metabolism of 5-fluorouracil in various human normal and tumor tissues.

The metabolism of 5-fluorouracil (5-FU) in tumors and normal tissues of humans was investigated in vitro. Phosphorylation of 5-FU was faster in tumor tissues than in normal tissues. Phosphorylating activity with 2-deoxy-alpha-D-ribose 1-phosphate (dRiblP) and ATP as cofactors was more active than that with alpha D-ribose 1-phosphate (RiblP) and ATP, or 5-phospho-alpha-D-ribosyldiphosphate (PPRibP) as cofactors. Phosphorylating activity in squamous cell carcinoma of the lung was similar to that in adenocarcinomas. Degradation of 5-FU was much faster in the liver than in other tissues including tumor tissues.

Adenocarcinoma↗
PubMed1980

Adenosine diphosphate ribosylation of histone H1 by purified calf thymus polyadenosine diphosphate ribose polymerase.

The mechanism of poly ADPR synthesis and the transfer of poly ADPR to histone H1 molecule by electrophoretically homogenous calf thymus poly ADPR polymerase containing DNA was examined. 1) An acid insoluble radioactive complex (I) was obtained after incubation of purified enzyme with [3H] NAD. The stability of (I) was examined by SDS-polyacrylamide gel electrophoresis. The complex (I) was stable against acid, SDS, urea, DNase and RNase, but labile against pronase, trypsin, alkali and snake venom phosphodiesterase treatment. The molecular weight of (I) was about 130 000 daltons estimated by SDS-gel electrophoresis. The radioactive products of successive alkali, venom phosphodiesterase and Pronase hydrolysis of (I) were PR-AMP and AMP. The mean chain length of poly ADPR of (I) was 20--30. These results suggest that the complex (I) is poly ADP-ribosylated poly ADPR polymerase. 2) Besides (I), a second radioactive peak (II) was observed when acid insoluble products obtained from an incubation mixture containing purified poly ADPR polymerase, [3H] NAD and purified histone H1 were analyzed on SDS-polyacrylamide gel electrophoresis. The molecular weight of (II) was estimated to be about 23 000 daltons. The complex (II) is eluted like histone H1 on CM-cellulose columns and hydrolyzed by alkali, trypsin and snake venom phosphodiesterase but not by DNase, or RNase. The comples (II) was extracted selectively by 5 per cent perchloric acid or 5 per cent trichloroacetic acid from mixture of (I) and (II). The mean chain length of poly ADPR of complex (II) and 5--20; these results suggest that the complex (II) is poly ADP-ribosylated histone H1. 3) Results 1) and 2) indicate that purified DNA containing, thus DNA independent, poly ADPR polymerase catalyzes two different reactions, the ADPR transfer onto the enzyme itself and onto histone H1 and the elongation of ADPR chains. Dimeric forms of ADP-ribosylated histone H1 was not observed. Free poly ADPR was observed only when very small quantities of enzyme were used for incubation.

Animals↗
PubMed1980

[Bilateral cysts of the brain, an unusual manifestation of multiple sclerosis in childhood (author's transl)].

In a 14 year old boy symptoms of an acute demyelinating disease (Multiple Sclerosis) were characterized by the history of retrobulbar neuritis, signs of increased intracranial pressure, asymmetric bilateral hemiparesis and generalized convulsion. Computerized tomograms and neuropathologic examinations revealed large bilateral cystic lesions one of which had to be operated. Clinical and pathological relations of this unique acute myelinoclastic form of severe demyelination are shown and discussed.

Acute Disease↗
PubMed1980

Effect of a single transfusion of donor-specific and nonspecific blood on skin allograft survival in mice.

The effect of a single transfusion of donor-specific or nonspecific blood on skin allograft survival was studied in ALS-treated mice. In the weak H-2-incompatible C3H/He to B6AF1 combination, transfusion of outbred CF1 blood induced significant prolongation of C3H/He skin graft survival when given over a wide interval of days between transfusion and skin grafting. In contrast, donor-specific C3H/He blood was effective only when given 10 days before grafting. Transfusion of either red blood cells or lymphocytes separated from CF1 or C3H/He whole blood also prolonged C3H/He skin graft survival. In the relatively strong H-2 incompatible DBA/2 to B6AF1 combination, significant prolongation of DBA/2 skin grafts was induced only by transfusion of donor-specific DBA/2- and H-2-compatible BALB/c blood. A single transfusion of C3H/He or CF1 blood failed to prolong DBA/2 skin graft survival. In the strong H-2-incompatible DBA/1 to B6AF1 combination, donor-specific DBA/1 blood was effective in prolonging DBA/1 skin graft survival. These results demonstrate that the effectiveness of donor-specific or nonspecific blood is dependent on (1) the degree of H-2 incompatibility of donor-recipient pairs and (2) timing of the blood transfusion relative to skin grafting.

Animals↗
PubMed1980

ALS in Rochester, Minnesota, 1925-1977.

The incidence, trend, and survivorship of ALS in the population of Rochester, Minnesota, was determined for the years 1925 through 1977. The average annual incidence was 1.76 per 100,000 population. There was a small but nonsignificant increase in the rate during the 53-year period. The male:female ratio was 1.1, and the male:female ratio of incidence rates was 1.6. The median age at onset was 66 years; the incidence rates increased with increasing age. Median survivorship was 22.5 months, and was longer for younger patients than for patients with an advanced age at onset. The demographic characteristics in this total community experience are believed to reflect the pattern of ALS more accurately than previously reported clinical series.

Age Factors↗
PubMed1980

[The hormonal regulation of the hepatic glycogenolysis in the newborn (author's transl)].

Through the hepatic glycogenolysis is the most important metabolism for energy source, the hormonal regulation in neonate is unknown yet. The neonatal rats were investigated chronologically in regard to liver wet weight, blood glucose, liver glycogen, liver glucose and liver cyclic AMP. And the influence of epinephrine and glucagon on the glycogenolysis were observed using isolated perifused rat liver. As a result, following conclusions were drawn. 1. In the earlier neonate, the source of the blood glucose mainly depended on the liver glycogen restored before birth. In the later neonate, the liver glycogen was reaccumulated by the progression of the suckling. 2. Although, in the earlier neonate, the influence of epinephrine on the glycogenolysis was more dominant than that of glucagon, the hepatic glycogenolysis was completely established by both hormones since the fifth day from birth. 3. In respect to the glucose output of liver, it was regulated by the interaction of these two hormones chronologically. 4. In the hepatic glycogenolysis of the neonates, just like that of the adults, cyclic AMP was also the second messenger of epinephrine and glucagon. 5. The third day after birth in the neonate was the critical period in the carbohydrate metabolism.

Age Factors↗