Chinese Med J Peking
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Chinese Med J Peking · Dec 1993
Comparative StudyContribution of differences in plasma binding of propranolol to ethnic differences in sensitivity. Comparison between Chinese and Caucasians.
Chinese are more sensitive to the beta-blocking and hypotensive effects of propranolol than Caucasians. To determine the contribution of ethnic differences in the plasma binding of propranolol to the differences in sensitivity, 8 Caucasians (22.8 +/- 1.5 yr) and 8 Chinese (31.8 +/- 2.1 yr) were studied following single doses of 0, 10, 20, 40 and 80 mg propranolol orally. The binding of propranolol in plasma was determined by equilibrium dialysis after addition of 300 mg racemic propranolol to the plasma. ⋯ The unbound fractions of both (-)-propranolol (16.06 +/- 0.79% vs 12.41 +/- 0.93%, P < 0.05) and (+)-propranolol (17.73 +/- 0.81% vs 14.33 +/- 0.89%, P < 0.01) were greater in Chinese than Caucasians, respectively. In both groups, the ratio of unbound (-) to (+)-propranolol was less than 1 (P < 0.01) and was greater in Chinese (0.91 +/- 0.01 vs 0.88 +/- 0.01) (P < 0.01), implying that in Chinese less isomers of both types were bound and there was a greater unbound proportion of the pharmacologically active (-)-propranolol which may contribute to their increased sensitivity to propranolol. It is demonstrated that ethnic differences in stereoselective protein binding may be an important variable in interindividual determinants of drug response.
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Chinese Med J Peking · Nov 1993
Guillain-Barre syndrome and Campylobacter jejuni infection. A study on the etiological characteristics of Guillain-Barre syndrome in China.
Fecal culture for Campylobacter jejuni with the method of Skirrow and serum class specific antibodies (IgG, IgM, IgA) against Campylobacter jejuni using a solid phase enzyme linked immunosorbent assay were performed in 17 cases of Guillain-Barre Syndrome, 17 other neurological disease controls, and 33 normal controls. The results revealed: 1. the incidence of Campylobacter jejuni infection, especially the recent one in Guillain-Barre Syndrome was much higher than in the other two groups; 2. the recent incidence of infection in those below 30 years old and those within the period of summer and autumn was higher than that above 30 years old and that in the other seasons. The results suggested that Campylobacter jejuni infection might be one of the important precipitating factors of Guillain-Barre syndrome and might play an important role in the epidemiological pattern of Guillain-Barre Syndrome in China.
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The effects of caffeine on diaphragmatic contractility and fatigue was investigated in 21 dogs. Diaphragmatic contractility was assessed by measuring transdiaphragmatic pressure (Pdi) during supermaximal stimulation of the phrenic nerves at different frequencies, and Pdi was measured with a pair of balloons. In protocol 1, the effect of caffeine on contractility of non-fatigued diaphragm was studied in 7 dogs. ⋯ In another group of 9 dogs, caffeine was infused during stable fatigue period and Pdi increased significantly at all frequencies of stimulation after caffeine infusion. The increase in Pdi was not due to changes in cardiac output or lung mechanics (Cdyn and Rtot), neither of which changed significantly after caffeine infusion. We conclude that caffeine improves muscle contractility both in non-fatigued and fatigued diaphragm in dogs.
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A study on the incidence and high risk factors of hypothermia in the newborn was carried out in a period of four months (Nov. 1988-Feb. 1989) in 6 counties of 3 provinces. Totally 14,809 newborns were studied, in whom 100 cases were found to be ill with sclerema, having an incidence of 6.7%. Gestational age, body weight, low room temperature, improper methods of thermopreservation during delivery and asphyxia are determined as the most probable high risk factors, in which gestational age and body weight are negatively correlated with the contraction of the disease. It suggests that the prevention of prematurity and asphyxia, and promotion of thermopreservation during delivery should be helpful in preventing sclerema of newborns.