The stress response to sensory contact in mice: genotype effect of the stimulus animal

Male wild house mice selectively bred for long and short attack latency (LAL and SAL, respectively) were previously shown to respond differently to chronic sensory contact stress with another SAL male. In the present study, it was investigated whether the genotype of the opponent played a role in the differential stress response of LAL and SAL mice. To this end, a LAL or SAL male was housed either under standard conditions (i.e. with a female), single, or in sensory contact with another LAL or SAL male for a period of 5 days. This period was chosen in order to study stress response adaptations. Although social isolation (singly housed) already induced changes in some physiological markers, in particular in LAL mice, the highest number of stress-induced changes was observed in LAL and SAL males living opposite a male of the other genotype. This was indicated in LAL mice by higher corticosterone levels, adrenal hypertrophy, and reduced seminal vesicle weight, and in SAL mice by higher ACTH levels and adrenal hypertrophy. Some mechanisms through which LAL and SAL mice could perceive each other as being different are proposed in the discussion, but it remains unclear why these mice show a differential stress response depending on the genotype of the opponent. In conclusion, it was demonstrated that a psychosocial stressor triggered line-specific changes in LAL and SAL mice, which were shown to be determined by the genotype of the stressor. These results open a new avenue to investigate mechanisms underlying genotypic-dependent stress responses.     

Early diagnosis in hypertrophic cardiomyopathy--case report

Disproportionate heart muscle enlargement compared with little or no chamber enlargement are characteristic for hypertrophic cardiomyopathy (HCM). The clinical course of HCM is highly variable. Many patients are asymptomatic or mildly symptomatic and may be relatives of patients with known disease. Unfortunately, the first clinical manifestation of the disease may be sudden death, frequently occurring in children and young adults, often during or after physical exertion. We present 2 cases of HCM who emphasize the variability of clinical and ECG modifications and underline the importance of routine echocardiography in patients with atypical cardiac symptoms in order to identify the disease and prevent high risk for sudden death.     

Risk of sudden death in patients with chronic renal failure and hemodialysis

Cardiovascular mortality in uremic patients treated by hemodialysis overrates ten times cardiovascular mortality in general population. Approximatively 40% of patients on iterative hemodialysis die from cardiac diseases, half of cases by sudden death. Several risk factors for sudden death are well known: QTc interval prolongation, decrease of RR interval <750 msec, decrease of heart rate variability, presence of late ventricular potentials (LVP), presence of high risk ventricular extrasystoles, decrease of ejection fraction (EF) <40 %, presence of left ventricular hypertrophy. Our study evaluated the above-mentioned risk factors for sudden death in patients with chronic renal failure on hemodialysis. We studied 37 patients, 22 males and 15 females, with mean age of 42 years old, without diabetes, heart failure and arrhythmias, without myocardial ischemia on ECG, being on hemodialysis (HD) programme for minimum 1 year (HD parameters are: 4 h x 3/week, qB = 300 ml/min, buffer = bicarbonate, Ca dialysate = 1.75 mmol/l, K dialysate = 2.1 mmol/l, conductivity = 135 mS). The patients were evaluated by echocardiography, standard and Holter ECG. Statistics evaluation was performed in SPSS v.9.0. Program. The results proved that 80% of patients on HD have risk factors for sudden death, which are closely related with age and hyperhydration. Statistics proved that presence of high-risk arrhythmias is connected with heart rate variability and prolongation of QTc interval (favored by HD). 50% of our patients have 2 to 4 risk factors for sudden death, which increase incidence of sudden death in patients on HD.     

Raman spectroscopy of tissue samples irradiated by protons

PURPOSE: Since the number of cancer patients treated by proton irradiation has increased in the last few years, it seems appropriate to study dose-dependent effects of proton irradiation on mammalian tissues in more detail. MATERIALS AND METHODS: Tissue samples of normal skin of mouse and swine, of a human tumour model xenograph, and of normal skin and a skin tumour (basal cell carcinoma) of a human patient of about 1 mm thickness were irradiated by 24 MeV protons (uniform delivered doses of 1, 7 and 50 Gy: skin of mouse and a human tumour model xenograph, and 0.5, 5 and 50 Gy: swine and human skin). Raman spectra of non-irradiated and irradiated samples were recorded and analysed. RESULTS: Amide I, P=O and C-O bond vibrations and aromatics were sensitive to the proton irradiation dose. In the C-H stretching region, the irradiation-mediated change of Raman spectra was significant only in the case of the skin tumour. CONCLUSIONS: It has been shown that Raman spectroscopy is suited to assess the radiation damage done to biological samples by protons. Proteins of the human skin tumour seem to be more sensitive to proton irradiation than proteins of normal human skin.     

Neural correlates of retrieval orientation: effects of study-test similarity

ERPs elicited by correctly classified unstudied items in tests of yes/no recognition memory were used to investigate the neural correlates of retrieval cue processing. Items in Experiment 1 consisted of pictures and their corresponding names, allowing study and test material to be factorially crossed in four separate study-test cycles. The ERPs elicited by unstudied pictures and words were, in each case, more negative-going when the study material belonged to the alternative rather than the same class of items. These findings demonstrate that previously reported ERP "retrieval orientation effects" depend on differences in similarity between study and test items, and not on the form of the sought for material. In Experiments 2a and 2b, study materials were auditory words and pictures, and the test items were visual words. In both experiments, ERPs elicited by unstudied test words were more negative-going when pictures rather than auditory words were the study material. Thus, ERP retrieval orientation effects do not depend on the employment of a copy cue condition. It is proposed that the effects reflect differences in the processing necessary to maximize overlap between cue and memory representations.     

Managing and analysing data from a large-scale study on Framingham Offspring relating brain structure to cognitive function

At the Framingham Heart Study under separate research grant funding from the National Institute of Aging, NIH, we are gathering brain structure and cognitive information on the Framingham Offspring, creating one of the largest known data sets to assess changes in brain structure associated with normative ageing and cognitive decline. Subject recruitment, data collection, data management and statistical analysis require a collaborative integrated effort on the part of the Framingham project team. Here we describe this effort, as well as the various brain structure and cognitive function parameters we are now collecting. We are currently performing analyses of data collected through 2002, and we discuss the statistical issues arising relating brain structure parameters to cognitive function.     

Impact of ambulatory,family-focused teamwork intervention on glycemic control in youth with type 1 diabetes

OBJECTIVE: To evaluate an ambulatory, family-focused intervention aimed at optimizing STUDY DESIGN: Study design We randomly assigned 105 children and adolescents, 8 to 17 years of age, with T1DM for < or =6 years, to a family-focused teamwork (TW) intervention or to standard multidisciplinary diabetes care (SC). Patients in both study groups were seen at 3- to 4-month intervals and were followed prospectively for 1 year. Measures of family involvement in diabetes tasks, DFC, and quality of life were performed at baseline and after 1 year. Hemoglobin A1c was measured at each visit. RESULTS: Patients (n = 100) completed follow-up, (50 in TW and 50 in SC). At entry, A1c was 8.4% +/- 1.3% in TW and 8.3% +/- 1.0% in SC. After 1 year, A1c was 8.2% +/- 1.1% in TW compared with 8.7% +/- 1.5% in SC (P <.05). Both groups had similar frequencies of blood glucose monitoring (BGM) and insulin dosing. Families exposed to the TW intervention maintained or increased family involvement significantly more than families exposed to SC (P =.05). In multivariate analysis, the TW intervention and the daily frequency of BGM significantly predicted A1c (R (2) = 0.17, P =.05). Despite increased family involvement, the TW group reported no increase in DFC or decrease in quality of life. CONCLUSIONS: The ambulatory TW intervention prevented the expected deterioration in glycemic control seen with SC in youths with T1DM of < or =6 years' duration. Successful family involvement may assist in the preservation of health and the prevention of long-term diabetes complications for youth with diabetes.     

The decision to take hormone replacement therapy among women with disabilities

Whereas making decisions during menopause can be challenging for all women, those with physical impairments face special issues with respect to menopause in general and hormone replacement therapy (HRT) in particular. In this correlational study the authors explored the factors such women consider when making decisions about HRT One hundred sixty-seven women with physical impairments throughout the United States completed surveys concerning their attitudes and knowledge about HRT Approximately half the menopausal women were currently taking HRT The strongest predictor of HRT use was women's perceptions of their health care providers opinions about their taking HRT, combined with their motivation to comply with the provider's recommendation. Thisfinding points to the significant role that nurses and other health care providers play in assisting women to make informed health care choices during menopause.     

Preshaping and continuous evolution of motor cortical representations during movement preparation

While a goal-directed movement is prepared, motor cortical neurons selectively change their activity in relation to prior information about movement direction. Only little is known, however, about the neuronal representation of partial information about this parameter. We investigated this question by training monkeys in a multidirectional centre-out pointing task. A preparatory signal provided prior information about one, two or three possible adjacent targets, thus manipulating the level of certainty about movement direction. After a 1-s delay, the response signal specified one of the precued targets to indicate the actual movement to be performed. Based on the directional tuning curves of individual motor cortical neurons determined during the reaction time interval, we constructed distributions of the population activation (DPAs), which we were then able to estimate as well during the preparatory period. We found that these distributions were preshaped by prior information, with peaks of activation centred over the range of precued movement directions. These peaks sharpened as the response signal approached, and shifted to the specified movement direction subsequent to that signal. Wider ranges of precued movement directions were represented by broader DPAs. Trials in which monkeys produced short reaction times were characterized by narrower distributions than trials with long reaction times. Our study thus provides evidence for (i) a graded preshaping of the neuronal population representation of movement direction by partial information about this parameter, and (ii) the continuous evolution of the preshaped population representation during the preparatory period towards movement initiation.