Non-invasive estimation of systolic blood pressure and diastolic blood pressure using photoplethysmograph components.

PURPOSE: Photoplethysmography (PPG) is a noninvasive optical technology that detects changes in blood volume in the vascular system. This study aimed to investigate the possibilities of monitoring the cardiovascular system status by using PPG. MATERIALS AND METHODS: Forced hemodynamic changes were induced using cardiac stimulants; dopamine and epinephrine, and PPG components were recorded by a noninvasive method at the peripheral blood vessels. The results were compared among 6 dogs. Endotracheal intubation was performed after an intramuscular injection of 25 mg/kg ketamine sulfate, and anesthesia was maintained with 2% enflurane. After stabilizing the animals for 15 min, 16 mg/mL diluted dopamine was injected into a vein for 2 min at 20 microg/kg min(-1) by using an infusion pump. Thereafter, the infusion pump was stopped, and 1 mg epinephrine was injected intravenously. Fluid administration was controlled to minimize preload change in blood pressure. RESULTS: After stimulant administration, systolic blood pressure (SBP) and diastolic blood pressures (DBP) increased. The direct current (DC) component, which reflects changes in blood volume, decreased while the alternating current (AC) component, which reflects changes in vascular compliance and resistance, increased. The correlation coefficient between SBP and the foot of the DC component was 0.939 (p < 0.01), while it was 0.942 (p < 0.01) for DBP and the peak of the DC component. The AC component could predict the increase in vascular resistance from a stable pulse blood volume, even with increased pulse pressure. CONCLUSION: These results support the possibility that PPG components may be used for easy and noninvasive measurement of hemodynamic changes in the cardiovascular system.

Inhibition of nitric oxide and tumor necrosis factor-alpha by moutan cortex in activated mouse peritoneal macrophages.

Moutan cortex (MC) is one of the most widely used Oriental herbal medicines for treating inflammatory diseases. In this study, the effect of MC on lipopolysaccharide (LPS) and recombinant interferon-gamma (rIFN-gamma)-induced production of nitric oxide (NO) and tumor necrosis factor (TNF)-alpha were examined using mouse peritoneal macrophages. MC inhibited the LPS/rIFN-gamma-induced expression of inducible nitric oxide synthase (iNOS) and TNF-alpha release. To clarify the mechanism involved, the effect of MC on the activation of nuclear factor (NF)-kappaB was examined. The LPS/rIFN-gamma-induced activation of NF-kappaB was almost completely blocked by MC at 0.5 mg/ml. These findings demonstrate that the inhibition of the LPS/rIFN-gamma-induced production of NO and TNF-alpha by MC is due to the inhibition of NF-kappaB activation.

Inequalities in nonfatal work injury: the significance of race, human capital, and occupations.

Little research is conducted to examine the determinants of nonfatal injury on the job. In particular, this study stresses the importance of race, human capital, and occupational conditions in explaining nonfatal injury at work. It measures nonfatal work injury as an episode of work injury, using the data from the 1988 Occupational Health Supplement (1988 OHS) to the National Health Interview Survey (NHIS). First, this study confirms no association between race and nonfatal injury at work. Second, the findings show that human capital, expressed through education and work experience, is the crucial determinant of nonfatal injury at work. In general, workers of more years of schooling and more work experience encounter less nonfatal injury at work than their counterparts. Third, the results also demonstrate the significance of occupational conditions (occupational positions and work activity) for nonfatal injury at work. Specifically, workers in professional occupations experience less work injury than workers in production occupations, but more work injury than workers engaged in clerical jobs. Even after controlling for occupational positions, there is a significant correlation between work activity and nonfatal work injury. Our study is a first step towards the causation of nonfatal injury on the job in terms of race, human capital, and occupational conditions. Therefore, the next step of work injury study needs to consider the influence of the other important determinants on nonfatal injury at work.