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Biomedical subjects

K Kokubun

Publications and source records attributed to K Kokubun.

At least 19 recordsLinked to original sources
PubMed1998

Microwave power absorption in a multilayered cylindrical model of man near a flat reflector.

There are usually objects in the vicinity when a person is exposed to electromagnetic waves. It is exceedingly difficult to calculate the whole-body average specific absorption rate (SAR) in the microwave frequency region using a realistic heterogeneous model of man. In this paper, we use a multilayered cylinder model to numerically examine the average SAR of an adult standing near a flat reflector exposed to microwave energy. We also offer a comparison with existing data from a realistic model for an E-polarized wave below 600MHz.

Absorption↗
PubMed1997

Further study of microwave power absorption in a multilayered cylindrical model of man.

The paper describes microwave power absorption in a typical human being, modeled as a multilayered dielectric cylinder. Average specific absorption rate (SAR) was calculated for E- and H- polarized incident wave for different conditions of the object. Comparison with an existing method is treated, and correction of an erroneous result therein is reported.

Absorption↗
PubMed1997

Multibody effects on microwave power absorption by multilayered cylindrical models of man.

This paper presents an analysis of the interactions among multiple human bodies, modeled by multilayered cylinders, exposed to microwaves. Cylinders are used because it is very difficult to compute the whole-body average specific absorption rate (SAR) at higher frequencies using a realistic human model. The average SAR is numerically discussed for a typical case of the linear array of two and three adult body models when the wave is vertically incident to the array.

Absorption↗
PubMed1992

[Prevalence and pathogenesis of iron deficiency in Japanese women (1981-1991)].

Iron deficiency anemia is the most prevalent among form of anemia in the world. In Japan, there is no overall report concerning prevalence and pathogenesis of iron deficiency. We estimated the prevalence of iron deficiency from the results of a survey of 3,015 Japanese women. The reference range for hemoglobin was derived from the average value of subjects with normal iron status (> or = 16% of transferrin saturation and > or = 12 ng/ml of serum ferritin). Using these reference standards, the prevalence of iron deficiency anemia, latent iron deficiency, storage iron deficiency, normal and others were 8.5%, 8.0%, 33.4%, 43.6% and 6.5%, respectively. The prevalence of iron deficiency anemia increased beginning in early lower teen girls, was highest in high teen-girls and, young women and decreased in elderly women. In elderly women, the cause of iron deficiency was often obvious associated with anemia of chronic disorders. The strategy for iron deficiency was discussed concerning iron fortification, mega-ingestion of vitamin C and low dose administration of iron tablets in the higher incidence group.

Adolescent↗
PubMed1990

[Sideroblastic anemia associated with adenine phosphoribosyltransferase deficiency].

We report a case of acquired idiopathic sideroblastic anemia associated with adenine phosphoribosyltransferase (APRT) deficiency. A 72-year-old male had been troubled with urolithiasis since his teens. In 1984, he was referred to us because of chronic renal failure and anemia. He was diagnosed as having sideroblastic anemia and required red cells transfusion regularly. In June 1989, he was admitted to our hospital because of cerebral infarction. Peripheral blood analysis showed pancytopenia. Bone marrow aspiration revealed hypercellularity with 36.2% erythroblasts, and 18.5% ringed sideroblasts of all nucleated cells. According to the FAB classification, a diagnosis of refractory anemia with ring sideroblasts was made. As his urinary stone consisted of 2, 8-dihydroxyadenine by analysis of infrared spectrum, genetic and enzymatic studies were performed. These studies indicated APRT deficiency. He died of pneumonia accompanied with progressive renal failure on August 9, 1989.

Adenine Phosphoribosyltransferase↗
PubMed1988

Ferrokinetic evaluation of erythropoiesis in patients with myelodysplastic syndromes.

Erythropoietic activity in patients with myelodysplastic syndrome (MDS) was evaluated by ferrokinetic measurements. Since the conventional plasma iron turnover of MDS patients increased with plasma iron levels after multiple blood transfusions, erythron transferrin uptake was chosen as a parameter of erythroid marrow activity. Although a correlation was shown between plasma iron level and plasma iron turnover (r = 0.50, 0.01 less than p less than 0.02), no correlation existed between the plasma iron level and erythron transferrin uptake (r = 0.25, p greater than 0.1). Erythron transferrin uptake, independent of plasma iron, was significantly higher in MDS patients than in normal subjects (110.6 +/- 67.6 and 67.6 +/- 18.8 mumol/l/dl, respectively; 0.01 less than p less than 0.02). An increased erythropoiesis occurring concomitantly with morphologically normal or increased erythroid cellularity was demonstrated in patients with MDS. The measurement of erythron transferrin uptake might be valuable as an accurate expression of erythroid activity in the hyperferremic state.

Erythropoiesis↗
PubMed1987

Candidate rotavirus vaccine (rhesus rotavirus strain) in children: an evaluation.

Fifty children, 3 months to 12 years of age, were given an experimental, orally administered, live attenuated rotavirus vaccine. Overall evidence of vaccine effectiveness as judged by vaccine virus shedding or a serologic response was seen in 82% of vaccinees. No clinical illness was seen in the rotavirus vaccinees when compared with 40 concurrently studied control children. No transmission to control children was observed even with close daily contact in a day-care setting. Young infants, generally less than 1 year of age, who had not previously experienced wild-type rotavirus infection shed significantly more vaccine virus. Limitation of virus shedding in those already exposed may be related to a prompt copro-IgA response which was significantly elevated by three days after vaccination. In summary, the development of this rotavirus vaccine, rhesus rotavirus-MMU-18006, is a promising step in the development of immunoprophylaxis against this major enteric pathogen.

Antibodies, Viral↗