Night shift work has often been associated with increasing degree and frequency of various psychologic complaints. The study examined whether psychologic states after night work are related to adaptive alterations of the cardiovascular and neuroendocrine systems. We studied 18 healthy nurses (age 29+/-2 years) engaged in a modified rapid shift rotation system (day work, 8:15-17:15; evening work, 16:00-22:00; night work, 21:30-8:30). Blood pressure, heart rate, RR interval variability (L/H and HF power spectrum for sympathetic and vagal activities), and physical activity were measured using a multibiomedical recorder for 24 h from the start of work during the night and day shifts. Plasma ACTH and cortisol concentrations were measured at the end of each shift and at 8:30 AM on a day of rest. Each subject's psychologic state was assessed using a validated questionnaire. Among the parameters measured, scores for confusion, depression, anger-hostility, fatigue and tension-anxiety were highest, and scores for vigor lowest, after a night shift. Systolic blood pressure and heart rate during work were lower during night shift than during day shift (119+/-2 vs. 123+/-1 mmHg, p<0.05 and 75+/-1 vs. 84+/-2 bpm, p<0.001, respectively). Both parameters were lower still (p<0.005 and p<0.05) when measured outside of the hospital under waking conditions following a night shift than following a day shift, even though the levels of physical activity were similar. The HF power spectrum of RR interval variability was greater not only during work (24.2+/-2.1 vs. 18.5+/-1.8 ms, p<0.005) but also during the awake period (29.1+/-2.5 vs. 24.4+/-2.6 ms, p<0.005) after the night shift compared with the day shift. Plasma ACTH and cortisol concentrations were lower after night work than in the day of rest (7.3+/-1.2 vs. 11.5+/-2.3 pg/ml, p<0.1 and 11.1+/-1.1 vs. 14.4+/-1.1 mg/dl, p< 0.05). Systolic and diastolic blood pressures during night shift work and the subsequent awake period correlated positively with scores for vigor and negatively with scores for confusion (p<0.05). Plasma ACTH and cortisol concentrations did not correlate with any psychologic scores. We conclude that psychologic disturbances after night work were associated with altered cardiovascular and endocrine responses in healthy nurses. Some of the psychologic complaints may be attributable to lower waking blood pressure.

SNP and 8-bromo-cGMP cause a negative inotropic effect and depress the rate of recovery from intracellular acidification that is mediated by Na(+)-H+ exchange in normal adult rat myocytes. In contrast, SNP and 8-bromo-cGMP do not modify cell contraction or pHi in hypertrophied myocytes.

No abstract

We compared the effects of endothelin-1 (ET-1) on intracellular pH, intracellular [

Objective The goal of this study was to determine the prevalence and clinical characteristics of headaches among socially active people working in the Tokyo metropolitan area. Methods We cross-sectionally surveyed 7,917 individuals. The survey assessed demographic characteristics, the prevalence and characteristics of headaches and physician attendance. Results The lifetime prevalence of migraines was 8.9%, while that of tension-type headaches was 14.7%. Women exhibited a higher prevalence of migraines than men (15% vs. 3.7%; p<0.001). The prevalence of migraines and tension-type headaches differed among occupations. Susceptibility to migraines and tensiontype headaches related to working overtime was observed. With respect to the influence of migraines on social activities, 22.4% of the migraineurs had been obliged to miss work due to headaches several times a year. As many as 59.4% of the sufferers had never consulted a physician about their headaches. Moreover, 24.6% of the migraineurs were not in touch with any physician at the time of the survey. The most common reason why they had stopped visiting their physician was that they had been told their headaches were not fatal. Conclusion Migraines adversely affect social activities. These data provide important information for understanding the features of migraines and tension-type headaches in socially active people working in the Tokyo metropolitan area.

A simplified polymerase chain reaction (PCR) assay was developed for fast and easy screening of mycoplasma mastitis in dairy cattle. Species of major mycoplasma strains [Mycoplasma (M.) bovis, M. arginini, M. bovigenitalium, M. californicum, M. bovirhinis, M. alkalescens and M. canadense] in cultured milk samples were detected by this simplified PCR-based method as well as a standard PCR technique. The minimum concentration limit for detecting mycoplasma by the simplified PCR was estimated to be about 2.5 × 103 cfu/mL and was similar to that of the standard PCR. We compared the specificity and sensitivity of the simplified PCR to those of a culture method. Out of 1,685 milk samples cultured in mycoplasma broth, the simplified PCR detected Mycoplasma DNA in 152 that were also positive according to the culture assay. The sensitivity and specificity of the simplified PCR were 98.7% and 99.7%, respectively, for detecting mycoplasma in those cultures. The results obtained by the simplified PCR were consistent with ones from standard PCR. This newly developed simplified PCR, which does not require DNA purification, can analyze about 300 cultured samples within 3 h. The results from our study suggest that the simplified PCR can be used for mycoplasma mastitis screening in large-scale dairy farms.

We tested the hypothesis' that glycolytic inhibition by 2-deoxyglucose causes greater impairment of diastolic relaxation and intracellular calcium handling in well-oxygenated hypertrophied adult rat myocytes compared with control myocytes. We simultaneously measured cell motion and intracellular free calcium concentration ([Ca2]I,) with indo-1 in isolated paced myocytes from aortic-banded rats and sham-operated rats. There was no difference in either the end-diastolic or peak-systolic [Ca2"]I between control and hypertrophied myocytes (97±18 vs. 105±15 nM, 467±92 vs. 556±67 nM, respectively). Myocytes were first superfused with oxygenated Hepes-buffered solution containing 1.2 mM CaC12, 5.6 mM glucose, and 5 mM acetate, and paced at 3 Hz at 360C. Exposure to 20 mM 2-deoxyglucose as substitution of glucose for 15 min caused an upward shift of enddiastolic cell position in both control (n = 5) and hypertrophied myocytes (n = 10) (P < 0.001 vs. baseline), indicating an impaired extent of relaxation. Hypertrophied myocytes, however, showed a greater upward shift in end-diastolic cell position and slowing of relaxation compared with control myocytes (A144±28 vs. 55±15% of baseline diastolic position, P < 0.02). Exposure to 2-deoxyglucose increased enddiastolic [Ca2+ ]; in both groups (P < 0.001 vs. baseline), but there was no difference between hypertrophied and control myocytes (218±38 vs. 183±29 nM, respectively). The effects of 2-deoxyglucose were corroborated in isolated oxygenated perfused hearts in which glycolytic inhibition which caused severe elevation of isovolumic diastolic pressure and prolongation of relaxation in the hypertrophied hearts compared with controls. In summary, the inhibition of the glycolytic pathway impairs diastolic relaxation to a greater extent in hypertrophied myocytes than in control myocytes even in well-oxygenated conditions. The severe impairment of diastolic relaxation induced by 2-deoxyglucose in hypertrophied myocytes compared with control myocytes cannot be explained by greater diastolic Ca2" overload, which implicates an increase in myofflament Ca2+-responsiveness as a possible mechanism. (J. Clin.

Spinal sympathetic neurons are distributed in cord segments from Th1 to L3. High spinal cord injury demonstrates severe orthostatic hypotension, but not lower cord injury. It remains to be clarified as to where is the critical spinal level disturbing neural cardiovascular regulations in response to orthostatic stress. To address this issue, beat-to-beat blood pressure (BP) (measured using a Finapres device) and RR interval (measured electrocardiographically) were recorded at rest and in a 60 degree head-up position in 26 patients with varying levels of spinal cord injury (C4 to Th12) and in 15 healthy (control) subjects. Sympathetic vascular tone was examined by the Mayer wave power spectrum of systolic blood pressure (SBP) variability. Baroreflex sensitivity was examined by transfer function analysis of SBP and RR interval variabilities. The Mayer wave power spectrum increased in response to postural shift in most patients injured at Th4 or below, whereas this parameter either remained unchanged or decreased in patients with higher-level injury. Baroreflex sensitivity tended to decrease with postural shift in patients injured at Th3 or below, whereas this parameter increased in all patients with higher-level injury. We divided spinal patients into high-level injury (Th3 or above, n = 14) and low-level injury (Th4 or below, n = 12) groups. Systolic blood pressure significantly fell (-10 +/- 4 mm Hg, P < .05) with postural shift in high-level injury group but did not change in low-level injury group or in control subjects. The low-level injury group and the control group demonstrated essentially similar autonomic nervous responses to postural shift, ie, a significant increase in Mayer wave power and an insignificant decrease in baroreflex sensitivity. On the contrary, the high-level injury group showed opposite responses, ie, an insignificant decrease in Mayer wave power and a significant increase in baroreflex sensitivity in response to postural shift. We conclude that spinal cord injury at Th3 or above eliminates normal neural cardiovascular responses to mild orthostatic stress in humans.