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Biomedical subjects

K Tarumi

Publications and source records attributed to K Tarumi.

11 recordsLinked to original sources
PubMed1995

Functional interactions of gene 32, 41, and 59 proteins of bacteriophage T4.

Genes 41 and 59 of bacteriophage T4 are involved in DNA recombination as well as in DNA replication. The 41 protein has a DNA helicase activity. The 59 protein has been recently purified and found to have a specific affinity for both 32 protein (single-stranded DNA-binding protein) and 41 protein (Yonesaki 1994, J. Biol. Chem. 269, 1284-1289). We examined the effects of 59 protein on ssDNA-dependent ATPase activity and DNA helicase activity of 41 protein in the presence or absence of 32 protein. The ATPase activity of 41 protein was strongly inhibited by 32 protein over a wide range of amounts from subsaturation to oversaturation of ssDNA. The 32 protein was also inhibitory toward DNA helicase activity. Addition of 59 protein effectively eliminated these inhibitory effects of 32 protein. Moreover, 59 protein facilitated 41 protein to overcome the barrier to initiate the unwinding reaction with a duplex flanking a single-stranded DNA gap. Intriguingly, 32 protein at an amount optimal for saturation of ssDNA stimulated the overcoming of the barrier when 59 protein was present. For the best circumvention of this initiation barrier, only eight monomers of 59 protein/one DNA substrate molecule containing 2900 nucleotides of ssDNA were required. These results strongly suggest that 59 protein modulates 41 protein activities by forming a complex with 41 protein and that 41 protein can produce recombinogenic ssDNA with the aid of 32 and 59 proteins.

Adenosine Triphosphate↗
PubMed1995

An investigation of the effects of lifestyle on care-seeking behavior using data from health insurance claims.

To clarify the effects of lifestyle on care-seeking behavior, we conducted a questionnaire survey using Morimoto's 8 lifestyle factors and tabulated the medical evaluations at annual medical checkup of 1212 male white-collar employees of a company (aged 21-60 years in 1991), and then extracted the health insurance data for these subjects for the first half of 1992 from the health insurance-carrier computer system. The percentage of employees who visited medical facilities, the number of days of medical care, and the medical fees reported on the health insurance claims were chosen as indices of care-seeking behavior, and the relationship of each index to lifestyle and medical checkup data was examined. The health practice index (HPI), which was obtained by summing the scores for the 8 lifestyle factors was associated with the medical evaluation as expected, but was inversely correlated with the indices of care-seeking behavior. The percentage of employees who visited medical facilities, the number of the days of medical care, and the total medical fees were all higher for the subjects with high HPI scores than for those with low HPIs. Our findings are consistent with those of other researchers who have found an inverse relationship between tobacco smoking and health insurance claims, which has been attributed to the degree of consciousness of health. Compared to smokers, non-smokers have high consciousness of health and tend to consult a doctor more frequently, with resulting increased frequency of medical facility consultation and days of medical care, as well as medical fees. Lifestyle is an important aspect of physical and mental health status.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[A survey of the inclinations of medical students towards becoming occupational physicians].

We conducted a survey to investigate medical students awareness of the activities of occupational physicians and their willingness to do postgraduate courses in this field. Those surveyed were fifth grade students in six universities in the Kinki district of Japan in 1993. In analyzing the responses of 368 eligible subjects, the response rate was 68.4% and the following results were obtained. 1) Only one of the 368 subjects expressed a desire to become an occupational physician after graduation, however 24.2% of those surveyed had considered becoming occupational physicians. More female students and, males over the age of 25, had considered becoming occupational physicians. Anxiety about a possible surplus of medical doctors in the near future was a factor that led them to consider becoming occupational physicians. 2) There were few negative responses concerning the activities of occupational physicians, even among those who had not considered becoming occupational physicians. 88.3% of those surveyed complained of a lack of information regarding postgraduate courses. 3) Responses were varied concerning conditions in the practice of occupational physicians. Those who had considered becoming occupational physicians were mostly concerned with the establishment of a system for the acceptance of occupational physicians in industry, while those who had not thought of becoming occupational physicians, considered practicing as occupational physicians as a sideline to regular clinic duties. 4) Having considered the above results and those of other researchers, we concluded that supplying more information related to the activities of occupational physicians and offering further postgraduate training programs in occupational medicine would encourage more medical students to become occupational physicians.

Career Choice↗
PubMed1993

An inquiry into the relationship between job strain and blood pressure in male white-collar workers.

We conducted a cross-sectional study to investigate the relationship between psychological load and blood pressure using white-collar male employees of a company located in an urban area in June, 1991. Excluding those with diseases which might induce hypertension or those under 20 yr and over 60 yr of age, 570 male subjects were eligible for analysis. Logistic regression analysis was applied to 461 subjects excluding 109 who showed unstable blood pressure level; the dependent variable was blood pressure class which contained 386 normotensives and 75 hypertensives. The explanatory variables were age, obesity, alcohol intake, cigarette smoking, habitual physical exercise, all well-known factors affecting blood pressure level, working time, commuting time, paid annual leave, and type of living (with family or alone) as objective workload, and Karasek's job strain as psychological workload. Odds ratio of job strain was statistically significant after adjusting for the foregoing factors, but in the case of high job strain, the prevalence of hypertension was low. Theorell has pointed out that contrary to the usual recognition those having a family history of hypertension tended to have a non-complaining life attitude and this indication seems to be the reason for the results of this analysis. Blood pressure is one of the most important problems in the field of industrial health and because of our highly industrialized society, it is necessary to consider psychological workload. Longitudinal observations which take into account psychological workloads must be planned, and personal traits represented by a family history of hypertension should be always taken into consideration.

Adult↗
PubMed1991

Co2+ and Ni2+ resistance in Saccharomyces cerevisiae associated with a reduction in the accumulation of Mg2+.

A mutant strain of Saccharomyces cerevisiae (NR 6), which can be associated with a reduction in the accumulation of Mg2+ has been isolated. This mutant strain displays resistance to both Ni2+ and Co2+, but not, however, towards Cu2+, Cd2+, Mn2+, Zn2+ and Cr2O7(2-). Both Co2+ and Ni2+ uptake by the mutant strain is less than by the wild type (CMR-50). The inhibitory effects of Ni2+ and Co2+ on the growth of both strains NR-6 and CMR-50 can be cancelled by increasing the concentrations of Mg2+ in the medium and to a lower extent by the addition of Ca2+ which results in a decreased uptake of these metals. It therefore appears that the resistant mechanisms of this mutant strain NR-6 is due to a reduction in the uptake of Co2+ and Ni2+ via a Mg2+ transport system.

Biological Transport↗
PubMed1990

[An inquiry into the factors affecting the complaints of subjective symptoms in VDT operators].

In a study of VDT workers the relationship between 1) their general life condition and working environment and 2) their eye, shoulder, neck, arm, waist and back complaints and their psychological symptoms was investigated. The subjects of the study were (147 workers whose age ranged from 18 to 39 years, and who had used VDT for a monthly average of more than 40 h. The results were as follows: 1) For most of the symptoms, a tendency was observed for females to complain more than males and for younger workers to complain more than the older workers. Neck, shoulder, arm, waist and back complaints were more common than psychological symptoms. These physical complaints appeared to be the most common among VDT workers. 2) The occurrence of eye-related symptoms is related to items directly affecting sight. This reaffirms the importance of illumination for the visual system. 3) This investigation showed that a relatively good VDT working environment was secured for the subjects of the present study. It is important that consideration be given to labor management such as provision of rest period and supervision.

Adolescent↗
PubMed1986

The "protocell": a mathematical model of self-maintenance.

The concepts of self-generation, autonomous boundary and self-maintenance are explained briefly. The "protocell" is presented as a model of self-maintenance which is based on simple physical mechanisms of diffusion and reaction. The time evolution of the surface of the protocell is taken into account explicitly in the form of a Stefan condition giving rise to a non-linear feedback of the surface motion to the reaction and diffusion processes inside the protocell. The spatio-temporal dynamics are investigated, particularly in the neighbourhood of the stationary states, showing a self-maintaining behaviour under a certain range of nutritional conditions. Under another set of conditions we find an instability leading to a division process so that the population of protocells becomes self-maintaining instead of the single individual. The presented formulation of the protocell model is crucially improved compared with a previous version which required boundary conditions at infinity. The previous version was not strictly self-maintaining since dynamics outside the cell were essential for its behaviour.

Animals↗
PubMed1985

Physico-chemical model of a protocell.

A physico-chemical model of a self-maintaining unity or protocell is constructed on the basis of reaction and diffusion processes. The surface motion of the protocell is taken into account explicitly by a so-called Stefan condition, which leads to a nonlinear feedback to the reaction and diffusion processes. The spatio-temporal dynamics in the neighbourhood of the steady states is investigated in the framework of linear stability analysis with the use of an expansion in terms of spherical harmonics Ylm. It is shown that modes with l greater than or equal to 2 become successively unstable with increasing nutrient supply. The leading instability with l = 2 initiates a process of the nonlinear dynamics which is interpreted as the onset of division. A stabilizing effect of surface tension is also discussed.

Cell Division↗
PubMed1983

Oscillating spatial structures of a tissue.

We present a simple mathematical model for the self-controlled growth of a tissue giving rise to an oscillating tissue size under certain conditions. The control is brought about by two substances (two inhibitors or one inhibitor and one nutrient) which influence the cell kinetics locally. The inhibitors are produced by the tissue itself (whereas the nutrient comes from outside but is consumed by the tissue which produces the same effect). Both diffuse freely throughout the tissue, and thus realize a communication between different parts of the tissue. In any case the tissue approaches a self-maintaining space-time structure with properties depending on the parameters of proliferation, death and inhibiting control. We discuss the conditions for this structure not to be time-independent but oscillating.

Cell Communication↗