Biomarkers of exposure and dose: state of the art.

Biomarkers provide methods to measure changes in biological systems and to relate them to environmental insults and disease processes. Biomarkers can be classified as markers of exposure and dose, markers of sensitivity, and markers of disease. It is important that the differences and applications of the various types of biomarkers be clearly understood. The military is primarily interested in early biomarkers of exposure and dose that do not require high levels of sensitivity but can be used to rapidly triage war fighters under combat or terrorist conditions and determine which, if any, require medical attention. Biomarkers of long-term radiation risk represent the second area of interest for the military. Biomarkers of risk require high sensitivity and specificity for the disease and insult but do not require rapid data turnaround. Biomarkers will help provide information for quick command decisions in the field, characterise long-term troop risks and identify early stages of radiation-induced diseases. This information provides major positive reassurances about individual exposures and risk that will minimise the physical and psychological impact of wartime radiation exposures.     

Utility of expectancy theory in predicting occupational choices in college students.

Introductory psychology students responded to measures of Expectancy and Valence with respect to 6 male-dominated and 6 female-dominated careers. Likelihood of choosing each of the 12 occupations was used as an indicator of force of behavior in V. H. Vroom's (1964) expectancy model. Results indicated that the Expectancy?×?Valence interaction for an occupation accounted for from 12% to 41% of the variance in tendency to choose that occupation, although expectancy alone was as good a predictor as the product. Gender differences were marked and consistent across expectancy, valence, and likelihood of choosing each occupation, varying in accordance with the traditionality of the occupation. Limitations of the study and implications for both further research and for career counseling are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sequential bilateral isolated lung perfusion in the rat: an experimental model

BACKGROUND: A model of isolated single-lung perfusion in the rat has been established in our laboratory to study the chemotherapeutic treatment of pulmonary metastases. A sequential bilateral isolated lung perfusion model was designed to investigate the feasibility of staged perfusions in the rat. METHODS: Twenty-four Fischer rats were randomized into three experimental groups of 8 rats each. All rats underwent left isolated lung perfusion. One, 2, or 3 weeks later, the rats in groups I, II, and III, respectively, underwent contralateral (right) perfusion. Five control animals (group IV) underwent sequential bilateral sham thoracotomies 1 week apart. Arterial blood gas analysis was performed 1 week after the second operation in the rats in groups I and IV. RESULTS: All animals survived the first operation, with 100% (8/8), 75% (6/8), and 100% (8/8) of the animals in perfusion groups I, II, and III, respectively, surviving the second operation. All control animals (group IV) survived the second sham thoracotomy. Arterial blood gas analysis did not show a significant difference in the oxygen or carbon dioxide partial pressure or the pH between group I and IV (p = 0.32, 0.96, and 0.76, respectively). CONCLUSIONS: Our experiments demonstrate that sequential bilateral isolated lung perfusion is safe in and well tolerated by the rat. This model can be used to investigate the safety and efficacy of staged perfusions with chemotherapeutic agents in the treatment of bilateral pulmonary metastases in the rat.     

Captopril modifies gene expression in hypertrophied and failing hearts of aged spontaneously hypertensive rats

The spontaneously hypertensive rat (SHR) exhibits a transition from stable compensated left ventricular (LV) hypertrophy to heart failure (HF) at a mean age of 21 months that is characterized by a decrease in alpha-myosin heavy chain (alpha-MHC) gene expression and increases in the expression of the atrial natriuretic factor (ANF), pro-alpha1(III) collagen, and transforming growth factor beta1 (TGF-beta1) genes. We tested the hypotheses that angiotensin-converting enzyme inhibition (ACEI) in SHR would prevent and reverse HF-associated changes in gene expression when administered prior to and after the onset of HF, respectively. We also investigated the effect of ACEI on circulating and cardiac components of the renin-angiotensin system. ACEI (captopril 2 g/L in the drinking water) was initiated at 12, 18, and 21 months of age in SHR without HF and in SHR with HF. Results were compared with those of age-matched normotensive Wistar-Kyoto (WKY) rats, and to untreated SHR with and without evidence of HF. ACEI initiated prior to failure prevented the changes in alpha-MHC, ANF, pro-alpha1(III) collagen, and TGF-beta1 gene expression that are associated with the transition to HF. ACEI initiated after the onset of HF lowered levels of TGF-beta1 mRNA by 50% (P<.05) and elevated levels of alpha-MHC mRNA two- to threefold (P<.05). Circulating levels of renin and angiotensin I were elevated four- to sixfold by ACEI, but surprisingly, plasma levels of angiotensin II were not reduced. ACEI increased LV renin mRNA levels in WKY and SHR by two- to threefold but did not influence LV levels of angiotensinogen mRNA. The results suggest that the anti-HF benefits of ACEI in SHR may be mediated, at least in part, by effects on the expression of specific genes, including those encoding alpha-MHC, ANF, TGF-beta1, pro-alpha1(III) collagen, and renin-angiotensin system components.     

A slow wave investigation of working memory biases in mood disorders.

Mood-congruent working memory biases were examined in a delayed matching to sample paradigm using the slow wave (SW) event-related brain potential (ERP) component. Mood-congruent working memory biases, indexed by SW amplitudes, were demonstrated among individuals experiencing a major depressive episode (MDE) and nondepressed controls but not individuals with dysthymia. However, analyses of symptom severity demonstrated that those with dysthymia exhibited significantly less negative SW amplitudes with increasing depressive mood severity, whereas individuals with major depression demonstrated more negative SW amplitudes with increasing depressive mood severity. These results are discussed in the context of diagnostic specificity for cognitive biases associated with working memory of mood-disordered individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prediction of long-term mortality in patients with rheumatoid arthritis according to simple questionnaire and joint count measures

This study examined changes in employment status and quality of work in 109 chronic pain patients who underwent a cognitive-behavioural pain management course; 68% of patients were female, mean age was 45 years, mean pain chronicity 10.7 years, 70% had spinal pain, and mean impairment on the Sickness Impact Profile was 26%. Twenty-six per cent of patients were employed at pre-treatment; the remaining 74% had been unemployed for 4.3 years on average. Measures of work status and quality, mood, pain, self-efficacy and walking performance were taken before admission, and at 1-, 6-, and 12-month follow-ups. Among employed patients quality of work scores improved by 35% from pre- to post-treatment (p < 0.01). Thirty per cent of previously unemployed patients returned to work during the 1-year follow-up, although employment status fluctuated greatly during this period. Non-workers were generally more impaired than workers on most measures, but the same measures did not differentiate between those who successfully returned to work and those who remained unemployed.     

Bidirectional Mobile Code Trust Management Using Tamper Resistant Hardware

Trust management in a networked environment consists of authentication and integrity checking. In a mobile computing environment, both remote hosts and mobile code are suspect. We present a model that addresses trust negotiation between the remote host and the mobile code simultaneously. Our model uses tamper resistant hardware, public key cryptography, and one-way hash functions.