The Use of Kits in the Analysis of Tissue Lipids Requires Validation.

The ready availability and ease of use of kits for the measurement of serum lipids has greatly facilitated these measurements. In many cases it would be convenient to use these kits in the determination of lipid concentrations in tissues. The successful application of serum kits in tissue analysis requires that two important issues be considered. First, the solvent system for the extraction of the lipids and the solvent used for analysis by the kit must be compatible with the reactions in the kit. Second, the concentration range in the analyzed solution must be within the range for which the kit is used. We report here that lipids in liver and adipose tissues may be significantly underestimated by the use of some kits. We recommend that the use of kits for tissue analysis of lipids be validated for the specific analysis.

The effect of olestra on the absorption, excretion and storage of 2,2',5,5' tetrachlorobiphenyl; 3,3',4,4' tetrachlorobiphenyl; and perfluorooctanoic acid.

Mice were gavaged with either (14)C-labeled 2,2'5,5' tetrachlorobiphenyl; 3,3',4,4' tetrachlorobiphenyl; or perfluorooctanoic acid. Absorption of these compounds was determined by assay of feces collected for 48 h after the gavage. Part of the animals received test diets containing olestra during this 48-hour period to determine its effect on absorption of the compounds. Mice that received the diet without olestra during this period were divided into groups that either continued the diet without olestra or changed to a diet containing olestra. These diets were continued for 7 days, and a second 48-hour fecal collection was made to measure the effect of olestra on enterohepatic circulation of the compounds and their metabolites. The animals were sacrificed, and blood, fat, and liver concentrations of (14)C were measured. Olestra decreased the absorption of 2,2',5,5' tetrachlorobiphenyl. It also reduced tissue and blood concentrations of this compound. Olestra also decreased the absorption of 3,3',4,4' tetrachlorobiphenyl, but it did not alter enterohepatic circulation or tissue concentrations. Olestra significantly increased the excretion of perfluorooctanoic acid in the second 48-hour collection, suggesting an effect on enterohepatic circulation. It did not, however, alter tissue concentrations of perfluorooctanoic acid. These data are consistent with previously observed effects of olestra on the absorption and storage of lipophilic compounds.

Management of a major box jellyfish (Chironex fleckeri) sting. Lessons from the first minutes and hours.

OBJECTIVE: To report the management of a serious box jellyfish (Chironex fleckeri) envenomation from the first minutes of bystander first aid and treatment by ambulance personnel to subsequent treatment in hospital. CLINICAL FEATURES: A 14-year-old girl sustained a serious Chironex fleckeri sting. There was no loss of consciousness, but the patient suffered severe pain, myocardial irritability, acute pulmonary oedema and mild systemic hypotension, due to the direct toxic effects of the venom. Thirst was a dominant symptom. INTERVENTION AND OUTCOME: Management involved rapid bystander action and call for ambulance assistance; and early intervention with oxygen/nitrous oxide administration, compression bandaging, antivenom administration and electrocardiographic monitoring at the site by ambulance personnel. Echocardiography in hospital three hours after the sting showed a normal myocardium. In hospital management resulted in recovery. Nocturnal itching of the sting persisted for six weeks. CONCLUSIONS: (i) Vinegar dousing may irritate freshly stung skin, but as a nematocyst inhibitor vinegar remains an essential part of the first aid treatment for cubozoan jellyfish stings. (ii) Compression/immobilisation bandaging was not associated with long-term harm to the sting area. (iii) The pain of an intramuscular antivenom injection may not be felt by a chirodropid sting victim, so safe injection protocols must be strictly observed. (iv) Ambulance services in other States whereas there is a risk of box jellyfish (Chironex fleckeri or Chiropsalmus quadrigatus) stings should be similarly trained and equipped to deal with serious jellyfish envenomations.

Cardioprotection and attenuation of endothelial dysfunction by organic nitric oxide donors in myocardial ischemia-reperfusion.

The effects of two nitric oxide (NO) donors were evaluated in a 6-h model of feline myocardial ischemia-reperfusion. After 80 min of a 90-min ischemic period, SIN-1 or C87-3754 or their respective controls (i.e., 0.9% NaCl or C88-3934, a control compound which does not release NO) were given i.v. as a bolus (0.1 mg/kg) and infused at 1 mg/kg/h for the entire 4.5-h reperfusion period. Administration of the active NO donors significantly decreased the necrotic area/area-at-risk ratio from 29 +/- 3% in the vehicle group to 9 +/- 2 and 11 +/- 5% in the SIN-1 and C87-3754 groups, respectively (P less than .001). The inactive NO donor C88-3934 failed to reduce infarct size (31 +/- 3%). Neither NO donor reduced the accumulation of neutrophils in the necrotic area when compared to their respective control groups, but both agents significantly attenuated coronary endothelial dysfunction as shown by a vasorelaxation to acetylcholine of 62 +/- 2 and 64 +/- 3% in the SIN-1- and C87-3754-treated arteries, as compared to only a 27 +/- 3 and 34 +/- 4% vasorelaxation in the vehicle and inactive NO donor groups, respectively (P less than .001). Our studies show that SIN-1 and C87-3754 exert beneficial effects in a 6-h model of myocardial ischemia-reperfusion. Both NO donors decreased myocardial necrosis and decreased the reperfusion-induced endothelial dysfunction without significantly altering the pressure-rate index (i.e., an index of myocardial oxygen demand).

Local bone mineral response to brief exercise that stresses the skeleton.

OBJECTIVE: To compare grip strength and bone mineral content in the forearm in women and to test the effects on bone mineral content of short periods of exercise that stresses the skeleton. DESIGN: Assessment of both wrists in 69 volunteers and of the non-fractured wrist in 30 patients followed by an exercise regimen entailing squeezing a tennis ball as hard as possible for 30 seconds each day for six weeks. SETTING: Old people's homes and outpatient departments of Hammersmith and Northampton general hospitals. PATIENTS: 99 Women, of whom 69 were volunteers and 30 had a fractured forearm. MAIN OUTCOME MEASURE: Grip strength and bone mineral content after six weeks and at six months after the exercises had stopped. RESULTS: The bone mineral content of the women's forearms was measured with a densitometer and the grip strength with a semi-inflated bag connected to an anaeroid barometer. Measurements before exercise showed that the two variables correlated closely, irrespective of age, and that there were significant differences in both between the dominant and non-dominant arms of the volunteers. After six weeks of exercise there was a mean increase in grip strength of 14.5% (95% confidence interval 9.9 to 19.2%) and in bone mineral content of 3.4% (1.4 to 5.3%) in the stressed forearms of the 77 women who attended for examination. After six months without exercise the improvements in the 33 women who attended for follow up had reversed. Women who had had a fractured forearm (n = 13), however, had continued to gain grip strength and bone mineral content in the arm that had not been injured. CONCLUSIONS: Grip strength in the forearm is a good indicator of bone mineral content. Both variables may be increased by brief periods of stressful exercise. If this principle can be applied to the whole skeleton it may provide a means of reversing osteoporosis.

A thermographic study of heat distribution during ultra-speed cavity preparation.

Thermography was employed to determine the pattern of heat generation, distribution and dissipation during ultra-high speed cavity preparation. Results indicate an increase in intrapulpal temperature during cutting procedures. No significant differences in the cooling effectiveness between air-water spray and air alone were found. Thermography appears to be an effective research tool for determining thermal changes.