The toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD] and its congeners involves binding to a specific TCDD [Ah] receptor, interaction of this complex with chromatin, and the ultimate production of pleiotropic responses. The mechanism whereby these effects are produced following interaction of TCDD with the receptor complex is not known. Oxidative stress following the production of reactive oxygen species (ROS) may play an important role in the toxic manifestations of TCDD. Thus, the dose and time-dependent effects of TCDD on the production of superoxide anion by peritoneal lavage cells (primarily macrophages) from rats were examined. A maximum increase in superoxide anion production occurred on day 1 after treatment in rats with 50 and 125 micrograms TCDD/kg. At 6 h after a single dose of 125 micrograms TCDD/kg, a 2.4-fold increase in superoxide anion production was observed in peritoneal lavage cells from rats. A single dose of 5 micrograms TCDD/kg had no effect on superoxide anion production by peritoneal lavage cells. A significant increase in DNA single strand breaks within peritoneal lavage cells occurred at 12 h after the oral administration of 50 micrograms TCDD/kg, and a maximum increase in DNA single strand breaks was observed on days 3-5 after treatment. No DNA damage was detected at a dose of 5 micrograms TCDD/kg. No difference was observed with respect to dose and time in the composition of the peritoneal lavage cells. The results clearly indicate that the oral administration of TCDD activates peritoneal lavage cells in rats, and that the activation precedes the formation of DNA single strand breaks.(ABSTRACT TRUNCATED AT 250 WORDS)
We previously demonstrated that near-infrared spectroscopy can be used to measure blood flow. The spectrum of blood is dominated by hemoglobin. Therefore, it should be possible to determine the concentration of hemoglobin in tissue using near-infrared transmittance. We attempted to do this in the finger using a unique handheld multiple wavelength spectrophotometer. We took samples from 73 subjects and performed repeat measurements in several subjects. Hemoglobin level was determined at the time of near-infrared measurement. We performed correlation analysis between the hemoglobin values and the absorbance values. There was a strong correlation between hemoglobin levels and the 14 wavelengths (r = 0.738, n = 121, SEE = 1.7). We categorized the patients by hemoglobin level as either normal (12-16 g/dl), mildly anemic (10-12 g/dl), or moderately anemic (<10 g/dl). There were 21 patients in the low hemoglobin group, 29 in the middle range, and 23 in the normal range. The mean hemoglobin levels were 8.4 +/- 0.3 g/dl for the low group, 10.9 +/- 0.1 g/dl for the mildly anemic group, and 13.8 +/- 0.3 g/dl for the group with normal hemoglobin. There was a clear separation of absorbance values among the three groups. The major differences seen were in the midrange of the spectrum. It is encouraging that this first study of hemoglobin measurement yielded data permitting a discrimination of hemoglobin levels. It is hoped that future refinements will lead eventually to a non-invasive technique for the measurement of blood hemoglobin concentration.
Randomly assigned streptokinase or heparin therapy was studied in 50 patients with deep vein thrombosis of less than 2 weeks' duration. Venography was performed prior to therapy, after 3 days, and after 10 days. Two radiologists who were unaware of the patient's therapy compiled a single average lytic score for each patient at each time interval. Lysis of venous thrombi was significantly greater with streptokinase than with heparin after 3 days, but not after 10 days of treatment. Lytic scores achieved with streptokinase were significantly better than those achieved with heparin therapy (P less than .01) in male patients who were symptomatic for 3 days or less. In females, regardless of the duration of symptoms, thrombolytic results obtained with streptokinase were not significantly different than results obtained with heparin.
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