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Biomedical subjects

K Aoki

Publications and source records attributed to K Aoki.

At least 757 records · Page 42Linked to original sources
PubMed1986

Contractile effects of Bay k 8644, a dihydropyridine calcium agonist, on isolated femoral arteries from spontaneously hypertensive rats.

Agonist actions of methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)- pyridine-5-carboxylate (Bay k 8644) were investigated in femoral and mesenteric arteries from 6-week-old spontaneously hypertensive rats (SHRs), and data compared with findings in normotensive Wistar-Kyoto rats (WKYs). The addition of Bay k 8644 produced a dose-dependent contraction in SHR femoral artery with a pD2 value of 8.55. Maximum contraction induced by this agonist (1 X 10(-7) M) was comparable to the maximum developed by K+-depolarization. Bay k 8644 was much less effective in eliciting the contractile responses on WKY femoral artery. Contractile responses of mesenteric and tail arteries to Bay k 8644 were weak and were not significantly different between SHR and WKY. Thoracic aorta was sensitive to the contractile response to Bay k 8644, but the sensitivity was not significantly different between SHR and WKY. Increased responsiveness to exogenously applied K+ was also observed in SHR femoral artery as compared to WKY. Contractile responses of SHR femoral artery to Bay k 8644 were antagonized competitively by nifedipine (pA2 = 8.36), a dihydropyridine Ca++ antagonist, but noncompetitively by diltiazem, a non-dihydropyridine Ca++ antagonist. When the effect of nifedipine on the dose-response curve for Bay k 8644 was determined in WKY femoral artery, there was a similar extent of rightward displacement of the dose-response curve to that seen in SHR. Nifedipine was less efficacious in relaxing the contractile response to Bay k 8644 compared to the contractile response to K+ in SHRs femoral arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1986

Inactivation of [Leu5]-enkephalin in three isolated preparations: relative importance of aminopeptidase, endopeptidase-24.11 and peptidyl dipeptidase A.

Enkephalin had been shown to be almost exclusively hydrolyzed by three peptidases in the previous studies. In the present investigation, the relative importance of three enzymes in the inactivation of [Leu5]-enkephalin was examined in three isolated preparations. Results showed that amastatin-sensitive aminopeptidase played the greatest role in both guinea-pig ileum and rat vas deferens while it played the similar role to either phosphoramdidon-sensitive endopeptidase-24.11 or captopril-sensitive peptidyl dipeptidase A in mouse vas deferens.

Animals↗
PubMed1986

[Epidemiological aspects of cancer and dietary habits].

Causal association between dietary habits and cancer is supported by both epidemiological and laboratory studies and dietary factor is at present one of the most important risks in carcinogenesis. However, the mechanisms of long low-dose exposure to dietary metabolites in carcinogenesis are little known, and there could be many other factors intervening over a long latent period, even if initiation and promotion of cancer occurred as a result of such dietary factors. The purpose of this paper was to review very preliminary reports on epidemiological studies carried out by Ogata-Segi among Japanese in Japan and by Haenszel among Japanese-Americans in Hawaii, together with those of others in the recent years and to evaluate the role of dietary factors in carcinogenesis. Recent epidemiological studies have repeatedly confirmed such dietary effects on cancers, but short-term intervention trials based on certain nutrients such as vitamins and minerals failed to demonstrate any suppressive effects among human populations. A number of other prospective studies on dietary intervention are in progress, but it appears to be difficult to obtain direct evidence from such studies on the population level, due to a lack of knowledge of the complicated metabolic processes of nutrients and their carcinogenic influence on cells and tissues.

Body Weight↗
PubMed1986

Viral conjunctivitis with special reference to adenovirus type 37 and enterovirus 70 infection.

The clinical and etiological findings in 727 patients with viral conjunctivitis treated from January 1982 through December 1984 at Aoki Eye Clinic in Sapporo, Japan, were presented. The age of the patients ranged from 11 days to 88 years, and the monthly incidences of the disease from 18 to 131 cases, with a clustering in the summer season. The etiological diagnosis was established in 399 (54.9%) of the 727 patients: adenovirus (Ad) 3 in 45 cases; Ad4 in 98 cases; Ad8 in 57 cases; Ad19 in 23 cases; Ad37 in 51 cases; untyped Ad in 33 cases; enterovirus (EV) 70 in 60 cases; herpes simplex virus type I in 24 cases and varicella-zoster virus in 4 cases. The clinical pictures of adenovirus 37 conjunctivitis were generally similar to those of adenovirus 8 conjunctivitis, and subconjunctival hemorrhage was more frequently seen in cases of EV70 conjunctivitis. EV70 cases showed nosocomial infection. In addition to Ad8, Ad37 seems to play an important role as a causative agent of epidemic keratoconjunctivitis in Japan.

Adenoviridae Infections↗
PubMed1986

Some cardiotonics enhance the effectiveness of angiotensin II-induced hypertension cancer chemotherapy in mice.

Angiotensin II-induced hypertension chemotherapy proved to be more effective than conventional chemotherapy using cis-diamminedichloroplatinum (II) (DDP), when applied to an established mouse mammary carcinoma. In an attempt to improve the effectiveness, a cardiotonic such as aminophylline or trans-pi-oxocamphor was added to a solution containing angiotensin II and DDP. A remarkable improvement in therapeutic efficacy was apparent as compared to angiotensin II hypertension chemotherapy. A possible synergism between angiotensin II and the cardiotonic may result in selective delivery of the antitumor drug to the tumor tissue.

Aminophylline↗
PubMed1986

[Anencephalus immunogenetic factor].

The T/t complex in the mouse is considered to be a gene locus that brings about neural tube defects. This locus is found to exist near the H-2 complex, which is the MHC of the mouse. Accordingly, it is conceivable that there exists a T/t-like complex near the HLA complex in humans. Studies on the HLA-A, -B, -DR, -DRw52, -53 and DQ loci of parents with anencephalus and affected offspring were undertaken with the aim of revealing the relationship between anencephalus and the HLA complex. The following results were obtained: The gene frequency of HLA-DR5 in a mother with anencephalus was significantly higher than in controls. HLA-DR materno-paternal compatibility was significantly higher than in control couples. An increase in HLA-DR, -DRw52, -53 and DQ homozygosity were observed among the affected offspring. These results indicated that there may exist an anencephalus immunogenetic factor in the HLA-D region.

Adult↗
PubMed1986

[Dietary habits among smokers].

Differences in dietary habits between smokers and non-smokers were examined, using the data of well-designed case-control study of colon cancer. Smokers took much more coffee, beef and sake than non-smokers, and smokers tended to take meals irregularly. These dietary habits showed dose-response relationship in the amount of smoking. Odds ratio of proportion of smokers with the above four factors to those without any factors was 10.5, and those with two or three factors were 2-6. These results suggest that the interaction of smoking and dietary habits should be analysed in epidemiological study on cancer.

Adult↗
PubMed1986

[Prevention of colonic ischemia following abdominal aortic aneurysmectomy by measurement of inferior mesenteric artery stump pressure].

To prevent postoperative colon ischemia, the inferior mesenteric artery (IMA) stump pressure measurement was performed in 60 patients undergoing unruptured abdominal aortic aneurysmectomy. IMA stump pressures were more than 40mmHg and IMA/systemic pressure ratios were more than 0.4 in 58 patients. The IMA was ligated in all of these patients. Colon ischemia developed in two of these 58 patients. In one, vigorous retractive trauma to the colon and the mesenterium seemed to be causative, and in the other, division of the branches of the IMA was causative. None of the other 56 patients developed colon ischemia. In remaining two patients, IMA stump pressures were less than 40mmHg and/or IMA/systemic pressure ratios were less than 0.4. In one of these two, reimplantation of the IMA was not performed until 12 hours after ligation of the IMA and postoperative ischemic colitis developed. In the other, the IMA was implanted into the prosthesis and colon ischemia did not develop. These results indicated that IMA stump pressure measurement is simple and very useful method to predict the risk of postoperative colon ischemia following abdominal aortic aneurysmectomy, and when IMA stump pressure or IMA/systemic pressure ratio is less than 40mmHg or 0.4, the IMA should be revascularised.

Adult↗
PubMed1986

[Cavoatrial bypass in obstruction of the inferior vena cava in the hepatic portion through the posterior route of the hepatic caudate lobe].

In a 32-year-old Japanese female who had a history of Sjögren's syndrome, the obstruction of the inferior vena cava in the hepatic portion was found associated with Budd-Chiari syndrome. The obstruction of the inferior vena cava was about 6 cm in length by cavography. Cavoatrial bypass grafting was successfully performed with a 16 mm ring reinforced expanded polytetrafluoroethylene graft, which ran behind the caudate lobe of the liver and connected to the right atrium via right pleural cavity. This may be the first report of the posterior route of the hepatic caudate lobe in cavoatrial bypass grafting in Japanese and English literature.

Adult↗
PubMed1985

Inactivation of cis-diamminedichloroplatinum (II) in blood and protection of its toxicity by sodium thiosulfate in rabbits.

The mode of inactivation of cis-diamminedichloroplatinum(II) (DDP) in the bloodstream and protection from its toxicity by sodium thiosulfate (STS) were investigated in rabbits. Plasma ultrafiltrate in rabbits given 5 mg/kg DDP IV and various excess molar ratios of STS IV were assayed for the active platinum levels with a new microbiological assay system using an E. coli strain. The active platinum species in the plasma were inactivated completely by co-administration of a 400-fold excess of STS IV. The rabbits were almost completely protected against both BUN increase and body weight loss normally caused by DDP when 400-fold doses of STS were given. Diuretic effects were also observed. Our data provide evidence for the basis of optimum use of STS to protect against DDP toxicity.

Animals↗
PubMed1985

A screening method for urinary methamphetamine--latex agglutination inhibition reaction test.

Methamphetamine in urine samples from abusers was detected by the latex agglutination inhibition reaction test with latex-antibody (Latex-Ab) and latex-methamphetamine (Latex-MA) reagents. Anti-methamphetamine antibody was produced in rabbits by immunization with bovine serum albumin (BSA)-methamphetamine conjugate. Latex particles were coated with antibodies or with rabbit serum albumin (RSA)-methamphetamine conjugate to obtain Latex-Ab and Latex-MA reagents, respectively. The results are read at 4-5 min after mixing the latex reagents. The sensitivity of this method for methamphetamine was 0.4 micrograms/ml urine. Methamphetamine analogs (methylephedrine, amphetamine, phentermine, methoxyphenamine, ephedrine, beta-phenylethylamine, OH-methamphetamine, OH-amphetamine, and OH-ephedrine) all cross-react in varying degrees, while glucosiurea and albuminurea give false positive results in the tests. Though attention must be paid to these effects this simple and rapid test is suitable for the mass screening of urine samples.

Alkaline Phosphatase↗