Heart rate and respiratory rhythm dynamics on ascent to high altitude

OBJECTIVE: To investigate the alterations in autonomic control of heart rate at high altitude and to test the hypothesis that hypoxaemic stress during exposure to high altitude induces non-linear, periodic heart rate oscillations, similar to those seen in heart failure and the sleep apnoea syndrome. SUBJECTS: 11 healthy subjects aged 24-64. MAIN OUTCOME MEASURES: 24 hour ambulatory electrocardiogram records obtained at baseline (1524 m) and at 4700 m. Simultaneous heart rate and respiratory dynamics during 2.5 hours of sleep by fast Fourier transform analysis of beat to beat heart rate and of an electrocardiographically derived respiration signal. RESULTS: All subjects had resting hypoxaemia at high altitude, with an average oxyhaemoglobin saturation of 81% (5%). There was no significant change in mean heart rate, but low frequency (0.01-0.05 Hz) spectral power was increased (P < 0.01) at high altitude. Time series analysis showed a complex range of non-linear sinus rhythm dynamics. Striking low frequency (0.04-0.06 Hz) heart rate oscillations were observed during sleep in eight subjects at high altitude. Analysis of the electrocardiographically derived respiration signal indicated that these heart rate oscillations correlated with low frequency respiratory oscillations. CONCLUSIONS: These data suggest (a) that increased low frequency power during high altitude exposure is not simply attributable to increased sympathetic modulation of heart rate, but relates to distinctive cardiopulmonary oscillations at approximately 0.05 Hz and (b) that the emergence of periodic heart rate oscillations at high altitude is consistent with an unstable cardiopulmonary control system that may develop on acute exposure to hypoxaemic stress.     

Renal interstitial sclerosis in aging: effects of enalapril and nifedipine

Microwave effects on drosophila morphogenesis were studied. Drosophila embryo were exposed by continuous wave 460 MHz at SAR = 1-5 Wt/kg. It was found that irradiation induced some morphosis such as imago legs and wings form alterations. These effects depended on embryo age, SAR and period exposure. It was proposed that the local microwave heating is responsible for describe effects.     

Comparison of thermal expansion of wood and epoxy adhesives

and Iroko, Clorophora excelsa) and four different epoxy resins have been compared using a modified test method that allows for nearly iso-hygric conditions of the wood specimens. Minor differences in TEC have been observed between wood in the transversal-to-the-grain direction and an experimental epoxy adhesive, which is considered highly compatible with wood on the basis of mechanical and ageing tests. Other commercial epoxy adhesives show greater differences in terms of TEC and a proportionally decreasing mechanical compatibility. According to these results, the evaluation of thermal properties can be considered very useful for a modelling approach to predict the long term behaviour of wood-epoxy adhesive interface.     

The pharmacokinetics and metabolism of heptapeptide--a prospective synthetic analog of tuftsin with psychostimulating action in rats

The lymphocyte blast transformation test (LBTT) with three tuberculin dilutions was used to examine 190 patients with varying pulmonary tuberculosis activity, of them 63 patients received chemotherapy. According to the blast formation in the patients' cultured peripheral blood cells by three tuberculin dilutions, a correlation was found between the clinical manifestations of the process and the functional activity of T lymphocytes. Thus, the greatest percentage (500 TU) of blasts in LBTT per mean PPD dose was detectable in patients with low LBTT results by three tuberculin dilutions with positive dynamics during chemotherapy. With further positive dynamics, the proportion of blasts in the cultured peripheral blood cells was highest per high PPD doses (5000 TU). On the contrary, patients with progressive tuberculosis displayed a oppositely directed phasic pattern.     

Which workers smoke?

OBJECTIVES: This article examines differences by occupation in daily cigarette smoking prevalence and intensity among full-time workers, and how these differences are associated with smoking restrictions at work. DATA SOURCES: Most of the data are from a Health Canada-sponsored Supplement to the 1994/95 National Population Health Survey (NPHS). The analysis is based on 5,674 respondents aged 15 to 64 who were full-time workers at the time of their interview. Comparable information is presented from the 1978/79 Canada Health Survey and the 1986 Labour Force Survey Smoking Supplement. MAIN RESULTS: In 1994/95, 28% of full-time workers were daily smokers, and about a third of them smoked 25 or more cigarettes a day. Smoking prevalence and intensity were lowest among white-collar workers and highest among blue-collar workers. Since 1978/79, there has been an overall decline in smoking prevalence, and since 1986, a decline in smoking intensity among all workers except those in outdoor blue-collar occupations. About 6 in 10 full-time workers who smoked daily encountered restrictions at work.     

Notch1 and Notch2 inhibit myeloid differentiation in response to different cytokines

We have compared the ability of two mammalian Notch homologs, mouse Notchl and Notch2, to inhibit the granulocytic differentiation of 32D myeloid progenitor cells. 32D cells undergo granulocytic differentiation when stimulated with either granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage colony-stimulating factor (GM-CSF). Expression of the activated intracellular domain of Notch1 inhibits the differentiation induced by G-CSF but not by GM-CSF; conversely, the corresponding domain of Notch2 inhibits differentiation in response to GM-CSF but not to G-CSF. The region immediately C-terminal to the cdc10 domain of Notch confers cytokine specificity on the cdc10 domain. The cytokine response patterns of Notch1 and Notch2 are transferred with this region, which we have termed the Notch cytokine response (NCR) region. The NCR region is also associated with differences in posttranslational modification and subcellular localization of the different Notch molecules. These findings suggest that the multiple forms of Notch found in mammals have structural differences that allow their function to be modulated by specific differentiation signals.     

Answering questions with an electroencephalogram-based brain-computer interface

OBJECTIVE: To demonstrate that humans can learn to control selected electroencephalographic components and use that control to answer simple questions. METHODS: Four adults (one with amyotrophic lateral sclerosis) learned to use electroencephalogram (EEG) mu rhythm (8 to 12Hz) or beta rhythm (18 to 25Hz) activity over sensorimotor cortex to control vertical cursor movement to targets at the top or bottom edge of a video screen. In subsequent sessions, the targets were replaced with the words YES and NO, and individuals used the cursor to answer spoken YES/NO questions from single- or multiple-topic question sets. They confirmed their answers through the response verification (RV) procedure, in which the word positions were switched and the question was answered again. RESULTS: For 5 consecutive sessions after initial question training, individuals were asked an average of 4.0 to 4.6 questions per minute; 64% to 87% of their answers were confirmed by the RV procedure and 93% to 99% of these answers were correct. Performances for single- and multiple-topic question sets did not differ significantly. CONCLUSIONS: The results indicate that (1) EEG-based cursor control can be used to answer simple questions with a high degree of accuracy, (2) attention to auditory queries and formulation of answers does not interfere with EEG-based cursor control, (3) question complexity (at least as represented by single versus multiple-topic question sets) does not noticeably affect performance, and (4) the RV procedure improves accuracy as expected. Several options for increasing the speed of communication appear promising. An EEG-based brain-computer interface could provide a new communication and control modality for people with severe motor disabilities.