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Biomedical subjects

K Aoki

Publications and source records attributed to K Aoki.

At least 703 records · Page 39Linked to original sources
PubMed1987

Toward a theory for the evolution of cultural communication: coevolution of signal transmission and reception.

A haploid sexual two-locus model of gene-culture coevolution is examined, in which a dichotomous phenotype subject to natural selection is transmitted vertically with probabilities dependent on the chosen parent's genotype and phenotype and the offspring's genotype. Stability conditions for the genetically monomorphic corner equilibria are obtained. In a specialization of this general model, one locus controls the transmission and the other controls the reception of adaptive information. The corner and edge equilibria of this doubly coevolutionary model are fully analyzed, and conditions for transmission and reception to coevolve are derived in terms of the efficiency of vertical transmission, the selective advantage gained from possessing the information, the costs of transmission and reception, and the recombination fraction between the two loci. Possible applications of the model are to the evolution of semantic alarm calls in vervet monkeys and the phonetic aspects of human language. In a third model with diploid genetics, we consider the initial increase of cultural transmission from a mutation-selection balance in which the adaptive phenotype is the consequence of a dominant gene at one locus. A second gene controls the transmission of the phenotype in such a way that a new mutant at this second locus permits learning of the adaptive phenotype from a parent who has it. This new mutant cannot increase when rare.

Animal Communication↗
PubMed1987

Comparative studies on aetiology and epidemiology of viral conjunctivitis in three countries of East Asia--Japan, Taiwan and South Korea.

A total number of 1105 cases with viral conjunctivitis, mainly epidemic kerato-conjunctivitis (EKC) consisting of 354 cases from Sapporo, Japan, of 628 from Kaohsiung, Taiwan and of 123 from Busan, Korea, encountered during the periods, 1980-81 and/or 1983, were studied aetiologically and epidemiologically. Patients were aged from 27 days to 88 years with a peak in the 20-29 year age group. Aetiological diagnoses were established in 610 cases (55%), consisting of 536 cases (49%) caused by adenoviruses and of 74 (7%) by EV 70. The most frequently detected agent was Ad 8 (57%), followed by EV 70 (12%), Ad 3 (9%) and Ad 19 (7%). The aetiological profiles of viral conjunctivitis were generally similar in three cities of East Asia. EKC (70%) was mainly caused by Ad 8, Ad 19 and Ad 37, but AHC (13%) by EV 70 and PCF (5%) by Ad 3 and Ad 11. Ad 19 and Ad 37 isolates in three cities were compared with the cleavage patterns with restriction endonucleases, BamHl, Smal, Sall and Hindlll. All of the Ad 19 isolates tested were identical to Ad 19a reported by Wadell et al, and all but three isolates of Ad 37 were identical to the Ad 37 prototype prevalent in Europe and the US. The three isolates of Ad 37, different from the prototype in cleavage pattern with Hindlll, designated as Ad 37A, were detected in Sapporo and Kaohsiung in 1980. From the cleavage patterns with four restriction endonucleases, Hindlll, BamHl, Sa1l and Sstl, the Ad 8 isolates in 1983 were divided into three subtypes, which were associated with the cities isolated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoviridae↗
PubMed1987

Treatment of phenylketonuria with a formula consisting of low-phenylalanine peptide. A collaborative study.

A method of preparation of a more palatable therapeutic formula for phenylketonuria (PKU), consisting of low-phenylalanine peptide (LPP), was reported. There were no adverse effects and, in fact, there was a reduced frequency of diarrhea in patients who received LPP formula for more than 6 months. The LPP formula can be used not only as a more palatable therapeutic milk for PKU, but also as an ingredient to make more palatable foods of low-phenylalanine content.

Adolescent↗
PubMed1987

The pathophysiological role of renal dopaminergic activity in patients with essential hypertension.

To evaluate the role of the renal dopaminergic system on renal water-sodium metabolism patients with essential hypertension (EHT), urinary excretion of dopamine, urinary excretion of sodium (UNaV) and fractional excretion of sodium (FENa) were all investigated before and after the administration of dopamine (3 micrograms/kg/min, intravenous infusion for 60 minutes), dopamine antagonist, metoclopramide (8 mg/m2 BSA, intravenous injection) or mild sodium loading in both normotensive subjects and benign EHT. In the basal values, no significant difference in urinary excretion of free (u-fDA), conjugated (u-cDA) or total dopamine (u-tDA) was found between normotensives and hypertensives. However, low renin EHT showed a pronounced reduction in u-fDA compared with normotensis subject and (NT) normal renin EHT. In this study, a significant reduction of u-cDA and of u-tDA was also found in those patients with low renin essential hypertension. In the normotensive and essential hypertensive groups UNaV or FENa showed a positive correlation with u-fDA (measured simultaneously), but not with u-tDA or u-cDA. The regression line between u-fDA and UNaV or FENa in EHT was shifted towards a lower u-fDA level than in NT. UNaV and FENa were increased by dopamine infusion and were decreased by metoclopramide injection in both NT and EHT. Changes of UNaV and FENa following dopamine or metoclopramide, showed a negative correlation with u-fDA measured immediately before the administration of these drugs. The enhanced natriuretic response to infused dopamine and the attenuated antinatriuretic response to injected metoclopramide were significant in low renin EHT, when compared with NT or normal renin EHT patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

A workplace-based case-control study of gastric ulcer among male municipal employees in Japan.

In order to detect risk factors of gastric ulcer among male workers in Japan, a workplace-based case-control study was conducted in a municipal government, using cases registered during 1981 to 1983 with individually matched controls. Statistically significant factors in univariate analysis were smoking, time interval from waking up to leaving home for job, meal time for supper, sleeping hours, anxiety, and gloomy feeling. Logistic analysis showed that among the above factors the significant relative risks were 11.9 (95% confidence interval: 1.6-89.4) for 1-9 cigarettes per day, 9.9 (2.6-37.7) for 10 cigarettes or more per day, and 5.3 (1.6-17.5) for gloomy feeling. These findings obtained among the male Japanese workers were almost consistent with those epidemiologic results in other developed countries that smoking and personality traits are major risk factors of gastric ulcer.

Adult↗
PubMed1987

Effects of Bay k 8644 and nifedipine on isolated dog cerebral, coronary and mesenteric arteries.

Vasoconstrictor effects of Bay k 8644, a dihydropyridine Ca++ agonist, and vasorelaxant effects of nifedipine were investigated in helical strips of dog cerebral (basilar, posterior cerebral and middle cerebral) and peripheral (coronary and mesenteric) arteries. The addition of Bay k 8644 produced a dose-dependent contraction in the absence of any contractile agent in the basilar artery with a pD2 value of 8.53. Similar sensitivity to Bay k 8644 was observed in the posterior cerebral, middle cerebral or coronary artery. Bay k 8644 was much less effective in producing a contraction in the mesenteric artery. An elevation of the concentration of extracellular K+ eliminated the difference between the responses to Bay k 8644 in the basilar and mesenteric artery. Contractile responses of the basilar artery to Bay k 8644 were antagonized competitively by nifedipine (pA2 = 8.17), but non-competitively by diltiazem. The pA2 values for nifedipine antagonism of Bay k 8644 responses with the elevated K+ were the same between the basilar and mesenteric arteries. Increased sensitivity to exogenously added K+ also was observed in cerebral and coronary arteries when compared with the mesenteric artery. The addition of nifedipine to an unstimulated strip produced a dose-dependent relaxation in cerebral and coronary arteries, but not in the mesenteric artery. When the cerebral and peripheral arteries were contracted with K+ to the same magnitude, nifedipine produced similar relaxations among these arteries. Nifedipine was less efficacious in antagonizing the contractile response to Bay k 8644 compared with the contractile response to K+ in cerebral arteries. These results suggest that 1) the voltage-dependent Ca++ channels in the cerebral and coronary arteries are in different states of activation from those in the mesenteric artery, 2) Bay k 8644 contracts the cerebral and coronary arteries by acting primarily on the same site, presumably dihydropyridine receptors of the voltage-dependent Ca++ channels at which nifedipine acts, 3) the dihydropyridine receptors were the same between the basilar and mesenteric arteries and 4) there may be a difference in the state of the Ca++ channel in the arteries between the stimulation with Bay k 8644 and K+-depolarization.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1987

Increased responsiveness to calcium agonist BAY k 8644 and calcium antagonist nifedipine in femoral arteries of spontaneously hypertensive rats.

Calcium (Ca2+) channel functions were compared in femoral arteries isolated from 6-week-old spontaneously hypertensive rats (SHR) and from age-matched normotensive Wistar-Kyoto (WKY) rats. BAY k 8644 (BAY), a dihydropyridine Ca2+ channel agonist, elicited a dose-dependent contraction in strips of SHR femoral arteries 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 KCl (K+) depolarization. BAY was less effective in eliciting a contraction in strips of WKY rat femoral arteries. Increased sensitivity to K+ was also observed in SHR femoral arteries. Contractile responses of SHR femoral arteries to BAY were antagonized competitively by nifedipine with a pA2 value of 8.36. When the effects of an elevation in the level of extracellular K+ on the contractile responses to BAY were determined in SHR and WKY rat femoral arteries, dose-response curves for BAY were not significantly different between the SHR and WKY rats. Femoral arteries from SHR, but not from WKY rats, relaxed when placed in a Ca2+-free solution. The addition of nifedipine (10(-10)-10(-7) M) to unstimulated strips produced a dose-dependent relaxation in femoral arteries from SHR, but not from WKY rats. These results suggest that (1) the increased responsiveness to BAY seen in SHR femoral arteries appears to occur because these arteries are more depolarized than WKY rat femoral arteries; and (2) BAY acts primarily on the same site, presumably the dihydropyridine receptors of the voltage-dependent Ca2+ channels, at which nifedipine acts.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1987

An epidemic of acute hemorrhagic conjunctivitis in the city of Sao Paulo.

This is a clinical and laboratory report on 98 patients with acute viral conjunctivitis who were referred to the Eye Clinic of the Escola Paulista de Medicina of Sao Paulo, Brazil, from February 1983 to February 1984. It was planned with the objective of confirming the importance of adenovirus and enterovirus 70 as etiological agents of viral conjunctivitis. The occurrence of an outbreak of acute hemorrhagic conjunctivitis during the summer of 1984 permitted a better study of enterovirus 70. In addition, we could demonstrate that sporadic cases, from March to July 1983, were caused by the same virus. This fact confirmed the idea that the spread of the disease was not related to the recent arrival of the virus in the community, but to weather conditions of heat and high humidity.

Adenovirus Infections, Human↗
PubMed1987

Molecular epidemiology of adenoviral conjunctivitis in Sapporo, Japan, and Manila, the Philippines.

DNA restriction endonuclease analysis was carried out on 48 adenovirus isolates from the conjunctival swabs of patients with acute conjunctivitis. Samples were obtained in Sapporo, Japan, and Manila, the Philippines, from October 1983 to October 1984. We identified new genomic variants among the isolates of Ad3 in Sapporo, and Ad4 and Ad11 in Manila, and these were designated as Ad3f, Ad4b, Ad11a and Ad11b, respectively. Ad7 isolates in Manila were identical to Ad7b reported by Wadell et al. In Sapporo, no Ad7 was isolated during the period of this study. One isolate in Sapporo, which was neutralized by both Ad34 and Ad35 antisera, showed identical restriction patterns to Ad35 prototype strain (Holden) with SmaI, BamHI and HpaI. However, with HindIII, the pattern was identical to that of Ad34 prototype strain (Compton). This isolate was tentatively designated as Ad34/35. Ad8 isolates in Sapporo were identical to Ad8B detected there from 1977 to 1981, while Ad8 isolates in Manila were prototype (Trim) strains. In both cities Ad19 isolates were all identical to Ad19a and Ad37 isolates were all prototype (GW). Genomic variants of Ad isolates in both cities are as follows: (Table: see text).

Adenoviridae Infections↗
PubMed1987

Potentiation of cytotoxicity of zinostatin under acidic conditions in vitro and in vivo.

The cytotoxicity and antitumor effects of zinostatin (NCS) were examined under various conditions of pH using cultured HeLa cells and a transplantable tumor line of WKA rats. The cytotoxicity of NCS against HeLa cells was highly dependent on the pH at ranges of 6-8. When HeLa cells were treated with 0.075 microgram/ml of NCS, the survival rate was about 1% at pH 6.0, while it was near 90% at pH 7.4 and pH 8.0. Even at pH 6.5-6.75, the survival rate was about 50% lower than that seen with pH 7.4 and pH 8.0. The ratio of the dose of NCS for a 90% cell mortality at pH 6.0 to that at pH 7.4 was less than one-seventh. Antitumor effects were assessed by local intra-arterial infusion against tumors 4 or 9 days after inoculation of 10(6) RBT-1 tumor cells into the thigh of rats. When NCS (0.7 mg/kg) in phosphate-buffered saline (PBS) (pH 7.4) or 5 mM lactate (about pH 3.0) was administered, the ratio of average tumor weight about 2 weeks after treatment (tumor weight of the rats given NCS in PBS/tumor weight of the rats given NCS in lactate) was 3.2 or 1.7 for the rats treated 4 or 9 days after tumor inoculation, respectively. Lactate or PBS alone had no effect on the growth of tumor. After treatment there was no difference in body weight change between the group treated with NCS in lactate and the group treated with NCS in PBS. We conclude that the cytotoxicity of NCS was potentiated under acidic conditions, both in vitro and in vivo.

Animals↗
PubMed1987

The long-term prognosis of patients gastrectomized for benign gastroduodenal diseases.

To study the long-term prognosis after gastrectomy, a total of 6,662 gastrectomized patients who had been operated on for benign gastroduodenal diseases between 1965 and 1980 were followed up from September 1, 1984 to May 30, 1986. The final vital status for the observed period could not be confirmed in 493 patients (7.4%), giving a follow-up rate of 92.6%. The average observation period was 13.1 years. The mortality from total deaths was almost identical to that of the general population adjusted for sex, age, and time trends of mortality, except for lower mortality among males in the first five years after operation. The risk of cancer mortality at all sites was lower than that of the general population, mainly due to the lower mortality from stomach cancer. This trend was not affected either by the type of gastroduodenal disease or by the method of operation. However, lung cancer mortality among males was significantly higher and one of the reasons for that could be excess smoking by males.

Alcohol Drinking↗