Elucidation of productive alanine recognition mechanism by Escherichia coli alanyl-tRNA synthetase.

Alanyl-tRNA synthetase (AlaRS) incorrectly recognizes both a slightly smaller glycine and a slightly larger serine in addition to alanine, and the probability of incorrect identification is extremely low at 1/300 and 1/170, respectively. Alanine is the second smallest amino acid after glycine; however, the mechanism by which AlaRS specifically identifies small differences in side chains with high accuracy remains unknown. In this study, using a malachite green assay, we aimed to elucidate the alanine recognition mechanism of a fragment (AlaRS368N) containing only the amino acid activation domain of Escherichia coli AlaRS. This method quantifies monophosphate by decomposing pyrophosphate generated during aminoacyl-AMP production. AlaRS368N produced far more pyrophosphate when glycine or serine was used as a substrate than when alanine was used. Among several mutants tested, an AlaRS mutant in which the widely conserved aspartic acid at the 235th position (D235) near the active center was replaced with glutamic acid (D235E) increased pyrophosphate release for the alanine substrate, compared to that from glycine and serine. These results suggested that D235 is optimal for AlaRS to specifically recognize alanine. Alanylation activities of an RNA minihelix by the mutants of valine at the 214th position (V214) of another fragment (AlaRS442N), which is the smallest AlaRS with alanine charging activity, suggest the existence of the van der Waals-like interaction between the side chain of V214 and the methyl group of the alanine substrate.

What Triggers a Diagnosis of HIV Infection in the Tokyo Metropolitan Area? Implications for Preventing the Spread of HIV Infection in Japan.

BACKGROUND: Japan has not succeeded in reducing the annual number of new HIV-infected patients, although the prevalence of HIV infection is low (0.02%). METHODS: A single-center observational study was conducted at the largest HIV clinic in Tokyo, which treats 15% of the total patients in Japan, to determine the reasons for having diagnostic tests in newly infected individuals. HIV-infected patients who visited our clinic for the first time between 2011 and 2014 were analyzed. RESULTS: The 598 study patients comprised one-third of the total reported number of new patients in Tokyo during the study period. 76% were Japanese MSM. The reasons for being tested which led to the diagnosis was voluntary testing in 32%, existing diseases in 53% (AIDS-defining diseases in 22%, sexually transmitted infections (STI) in 8%, diseases other than AIDS or STIs in 23%) and routine pre-surgery or on admission screening in 15%. 52% and 74% of the study patients and patients presented with AIDS, respectively, had never been tested. The median CD4 count in patients with history of previous testing (315/µL) was significantly higher than that of patients who had never been tested (203/µL, p<0.001). CONCLUSIONS: Only 32% of the newly HIV diagnosed patients were diagnosed because of voluntary testing, and 53% were diagnosed due to presence of other diseases. These results remain unchanged from our previous report 10 years earlier (2000-2004) on newly diagnosed patients at the same clinic. HIV testing has not been widely used by newly diagnosed patients in the Tokyo metropolitan area.

Improvement of endocardial border delineation during dobutamine stress echocardiography with Levovist.

OBJECTIVES: This study evaluated whether the use of Levovist improves endocardial border delineation during dobutamine stress echocardiography. METHODS: Thirty patients (20 men and 10 women) were enrolled in this study. Dobutamine was infused intravenously using an incremental regimen of 5, 10, 20, 30, and 40 micrograms/kg/min, each dose for 3 min. Levovist (277 mg/ml), dissolved in 9 ml of 5% dextrose, was infused intravenously. Two ml was infused at rest, 10, and 20 micrograms/kg/min. Three ml was infused at peak dobutamine dosage. Echocardiograms were recorded on videotapes. A endocardial border delineation score index (EDSI) was used for image analysis. The EDSI was obtained from each of 12 segments of the left ventricular wall (30 patients) in the rest and peak stress periods, before and after Levovist. Data from a total of 1,440 segments were analyzed separately. RESULTS: The mean EDSI at rest was 2.2 +/- 0.6 without contrast medium, and 2.4 +/- 0.7 with contrast medium (p < 0.05). The mean EDSI during peak stress was 2.0 +/- 0.7 without contrast medium, and 2.2 +/- 0.6 with contrast medium (p < 0.05). The wall-by-wall EDSI revealed that the delineation of apical-septal, mid- and apical-lateral, apical-inferior, and apical-anterior segments was improved significantly with Levovist in the rest and peak stress periods. CONCLUSIONS: Delineation of the apical-septal, mid- and apical-lateral, apical-inferior, and apical-anterior segments was improved significantly with Levovist during dobutamine stress echocardiography.

A women's support group for Asian international students.

International students underuse counseling services, which are grounded in Western cultural values. The authors describe a support group for Asian international students that they launched at a large midwestern university to help students feel at ease with American university life, address homesickness, language problems, and academic and social stressors. Co-leaders created a safe and culturally sensitive atmosphere where the women could network, socialize, and address their issues. Group treatment offers many advantages over individual counseling and can enhance the health of international students.

Personal dimensions of identity and empirical research in APA journals.

This study reviewed 402 empirical research papers published during 1999 in 9 American Psychological Association journals from the perspective of the Personal Dimensions of Identity (PDI) model. Descriptions of participants were reviewed to determine whether researchers reported information concerning Dimensions A, B, and C of the PDI model. PDI A and B Dimensions of age, gender, education, and geographic location were reported with the highest frequency: 88.56%, 89.30%, 78.50%, and 73.88%, respectively, whereas race/ethnicity was reported with moderate frequency, 60.70%. The remaining PDI A Dimensions of language, physical disability, sexual orientation, and social class, and the remaining B Dimensions of citizenship status, employment status, income, marital status, military experience, occupation, and religion, were reported in relatively low percentages of studies.