Sources of stress and psychological disturbance among dental students in the West Indies

The aim of this study was to investigate sources of stress and psychological disturbance in dental students across the five years of undergraduate study at a dental school in Trinidad. Eighty-three percent of students completed a modified version of the Dental Environment Stress questionnaire (DES) and the Brief Symptom Inventory (BSI). On a scale ranging from 0 (not stressful) to 5 (highly stressful), overall mean DES scores for each of the five years of study were 1.58, 1.83, 2.65, 2.39, and 2.61 respectively, suggesting that levels of stress increase over the five years with a noticeable spike at the transition between the preclinical and clinical phases. Significant differences were found between specific stressors across the five years of study. Seven specific stressors and the stressor domains of Academic work and Clinical factors were more stressful for female students (t-test p < 0.05). The Global Severity Index of the BSI indicated that 54.8 percent of males and 44.2 percent of females were in the clinical range indicating significant psychological disturbance. Psychological disturbance was significantly associated with stress levels for male students (Spearmans rank correlation r = 0.56; p < 0.001), but not generally for female students. Further development is needed of dental educational programs that enhance students' psychosocial well-being.     

HIV-1 and HIV-2 seroprevalence and risk factors among hospital outpatients in the Eastern Region of Ghana, West Africa

A cross-sectional study of 854 outpatients seen at three hospitals in the Eastern Region of Ghana, West Africa assessed HIV-1 and HIV-2 seroprevalence rates and associated risk factors. During mid-1999, patients were tested in an anonymous study linked to a questionnaire and abstracted record data in three distinct communities with differing levels of urbanization. Combined HIV seroprevalence rates were 19.2% for Agomanya, the most rural community, 5.1% for Akwatia, and 3.4% for Nkawkaw, the most urbanized community. HIV-1 infection alone accounted for 84.5% of cases, compared with 9.5% and 6.0% for HIV-2 and dual infection, respectively. In a multivariable model, the Agomanya location was significantly associated with HIV status (odds ratio [OR], 7.7; 95% confidence interval [CI], 2.9-20.1; p <.0001). Employed people were also more likely to be infected (OR, 4.3; 95% CI, 1.02-18.3; p =.047). Among prenatal patients, those from Agomanya were more likely to report no live-in partner or spouse compared with Nkawkaw and Akwatia (p <.0001). These findings suggest sexual partner exchange patterns may be more useful in explaining HIV seroprevalence rates than level of community urbanization. Intervention programs directed at these high risk populations for HIV infection in Ghana are urgently needed.     

Prevalence of blood-borne infectious diseases in blood donors in Ghana

Transfusion-transmissible infections among 808 blood donors in Ghana were investigated in 1999. Antibody seroprevalences of 3.8, 0.7, 8.4, and 13.5%, respectively, for human immunodeficiency virus, human T-cell lymphotrophic virus type 1, hepatitis C virus (HCV), and Treponema pallidum were obtained. The seroprevalence of HCV infection was confirmed to be 0.9% after supplementary testing, and the transfusion risk potential of these pathogens was demonstrated.     

Response to desipramine treatment in adolescent major depression

Thirty adolescents (ages 15-20) who met DSM-III-R criteria for major depressive disorder completed a double-blind, placebo-controlled, 6-week, fixed-dose (200 mg daily) study of desipramine (DMI). Thirty-three percent of the placebo group and 50 percent of the DMI group improved (greater than or equal to 50% change on the Hamilton Rating Scale for Depression). Subjective reports of adverse effects did not significantly differentiate the two groups. Major adverse effects, necessitating study discontinuation, occurred solely in the DMI group.     

正交试验法优选右旋糖酐40葡萄糖注射液澄明度的工艺

目的：应用正交试验法优选右旋糖酐４０葡萄糖注射液澄明度的工艺。方法；选择活性髅用量，中间品ｐＨ值与砂棒回流时间等三因素，每个因素取２个水平，按Ｌ８（２＾７）正交安排实验，用２个指标评定工艺的优劣。结果；采用活性炭用量为３．０％，中间品ｐＨ值为４．５，砂棒回流时间４５ｍｉｎ的工艺条件最佳。     

Compensation for respiratory motion by gated radiotherapy: an experimental study

Respiratory organ motion is known to be one of the largest intrafractional organ motions. Therefore, it is important to investigate the potential benefit of gated dose delivery approaches which aim to account for the respective dose uncertainties. In this study respiration is simulated by a moving lung phantom; the movement is not restricted to a normal sinusoidal progression and simulates the one of the embedded lung tumour in the cranial-caudal direction. An IMRT plan with a total of 29 beam segments was designed for the treatment of this tumour. It was irradiated in its resting position-which is the position at exhalation-and during movement. Furthermore the irradiation was triggered using different amplitude thresholds, which means that the irradiation only proceeded if the deviation of the tumour's position from its resting position is smaller than the given threshold. We determined the gating-related increase of the treatment time for various gating procedures. We also measured the resulting dose distribution in specific slices of the phantom perpendicular to the direction of the movement using film dosimetry and compared it to the dose distribution of the static case. Since these film measurements cannot be done inside the whole tumour, additionally the movement and gating was simulated using the planning software to calculate the 3D dose distribution inside the tumour and to generate dose volume histograms for different treatment modalities. The total treatment time was observed to increase by 20%-100% depending on the individual gating threshold and can be calculated easily. The analysis of the films showed that irradiation without gating leads to significant underdosages up to 33%, especially at the edge of the tumour. With gating it is possible to considerably reduce this underdosage down to 9% depending on the trigger threshold. The calculation of the dose volume histograms makes it possible to find a reasonable compromise between the improvement of the dose distribution and the increase of the treatment time.