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Biomedical subjects

Aya Kobayashi

Publications and source records attributed to Aya Kobayashi.

7 recordsLinked to original sources
PubMed2006

Efflux of sphingomyelin, cholesterol, and phosphatidylcholine by ABCG1.

Cholesterol and phospholipids are essential to the body, but an excess of cholesterol or lipids is toxic and a risk factor for arteriosclerosis. ABCG1, one of the half-type ABC proteins, is thought to be involved in cholesterol homeostasis. To explore the role of ABCG1 in cholesterol homeostasis, we examined its subcellular localization and function. ABCG1 and ABCG1-K120M, a WalkerA lysine mutant, were localized to the plasma membrane in HEK293 cells stably expressing ABCG1 and formed a homodimer. A stable transformant expressing ABCG1 exhibited efflux of cholesterol and choline phospholipids in the presence of BSA, and the cholesterol efflux was enhanced by the presence of HDL, whereas cells expressing ABCG1-K120M did not, suggesting that ATP binding and/or hydrolysis is required for the efflux. Mass and TLC analyses revealed that ABCG1 and ABCA1 secrete several species of sphingomyelin (SM) and phosphatidylcholine (PC), and SMs were preferentially secreted by ABCG1, whereas PCs were preferentially secreted by ABCA1. These results suggest that ABCA1 and ABCG1 mediate the lipid efflux in different mechanisms, in which different species of phospholipids are secreted, and function coordinately in the removal of cholesterol and phospholipids from peripheral cells.

ATP Binding Cassette Transporter, Subfamily G, Mem↗
PubMed2006

[A case of multi-drug resistant recurrent breast cancer with multiple bone metastasis responding to TS-1 and trastuzumab].

We experienced a case of multi-drug resistant recurrent breast cancer with multiple bone metastases achieving a significant improvement by TS-1 and trastuzumab. The prior treatments including taxane or vinorelbine and trastuzumab were changed in the regimen to TS-1 and trastuzumab because of the progressive disease. TS-1 was administered orally at 100 mg/day everyday for 2 weeks, followed by a 1-week rest interval as 1 cycle, and trastuzumab was injected at 2 mg/kg/week for 4 weeks, followed by a 1-week rest interval as 1 cycle. After 3 cycles of the treatment, the level of tumor markers and tumor sizes of bone metastases became reduced. In conclusion, the combination treatment of TS-1 and trastuzumab is thought to be effective for multi-drug resistant recurrent breast cancer.

Antibodies, Monoclonal↗
PubMed2003

Genetic variation of sex allocation in the parasitoid wasp Heterospilus prosopidis.

The genetic variation of sex ratio and sex allocation were examined in a series of half-sib analyses on the sex ratio of braconid parasitoid wasp Heterospilus prosopidis populations collected in Hawaii and Arizona. The mean threshold value and the range of the threshold for change in the sex of offspring in response to resource quality (host size) were determined. Estimates of the narrow-sense heritability (h2) of sex ratio at a specific host size ranged from 0.185 to 0.315, and those of the sex changing point (threshold value) ranged from 0.220 to 0.342. The coefficient of variation (CV(A)) of sex ratio was significantly larger than CV(A) of body weight. We discuss factors that maintained the significant additive genetic variation of sex ratio.

Analysis of Variance↗
PubMedDate not supplied

Factors associated with attitude and hypothetical behaviour regarding brain death and organ transplantation: comparison between medical and other university students.

The aim of this study was to investigate the factors, including knowledge, that determine an individual's attitudes and behaviours regarding brain death and organ transplantation using questionnaires among medical and other university students. A total of 522 students (388 medical and 134 other) answered a questionnaire. The survey included the individual's knowledge about brain death, attitudes towards brain death and organ transplantation, and hypothetical behaviours assuming their willingness to donate their own or their family's organs. Medical students were more likely to have knowledge about brain death and to accept brain death and organ transplantation compared with other students, while there was no difference in their willingness to donate their own or their family's organs. Logistic regression analysis was used to assess the effects of various factors on the attitudes and behaviours. In both medical and other students, confidence in brain-death diagnosis by doctors was independently associated with their willingness to donate their own organs after the adjustment for other factors, including knowledge (odds ratio [OR], 1.85; 95% confidence interval [CI], 1.15 to 2.97 and OR, 4.97; 95% CI, 1.01 to 24.39, respectively). An increase in knowledge may cause positive attitudes towards brain death and organ transplant. Meanwhile, reducing uncertainty about the brain-death diagnostic process might have a beneficial effect on the willingness to donate organs.

Adult↗