HIV and AIDS in inpatient dermatology. Approach to the consultation.

In the inpatient setting, the dermatologic consultant is called on to address the whole spectrum of cutaneous disease seen in HIV/AIDS patients, with severity varying from severe life-threatening to less serious conditions that dramatically affect quality of life. Rather than reviewing a "laundry list" of conditions associated with HIV/AIDS or the most severe conditions, this article aims to demonstrate a systematic approach to inpatient dermatology consultation in HIV/AIDS patients and to briefly review several common and interesting topics frequently addressed in the inpatient setting (e.g., medications issues, and phototherapy in HIV-infected patients).

Mesothelioma and lung tumors attributable to asbestos among petroleum workers.

BACKGROUND: Asbestos exposure has been definitively found to be associated with both mesothelioma and lung cancer. Nevertheless, in the overall population of oil refinery workers potentially exposed to asbestos, many studies clearly show a definitely increased risk of mesothelioma, but no proven excess of lung cancer after comparison to the general population. Through the presentation of new data and the re-appraisal of two recent and independent epidemiological studies conducted in Liguria, Italy, and Ontario, Canada, we attempt to shed light on this apparently paradoxical finding. METHODS: Lung cancer mortality was studied among maintenance workers exposed to asbestos, and among two other subgroups of refinery employees: blue collar and white collar workers. The comparison with blue collar workers was performed in order to take into account the role of healthy worker effect, smoking habit, and the socioeconomic level. The comparison with white collar workers was performed to control for other occupational lung carcinogens. RESULTS AND CONCLUSIONS: Results reveal a consistency between the two studies and show that 96-100% of the mesotheliomas and 42-49% of the lung tumors arising among maintenance workers were attributable to asbestos exposure. Our new analysis, estimating two cases of asbestos-related lung cancer for each case of mesothelioma, confirms published findings on the magnitude of asbestos-related tumors in oil refineries.

Asbestos-associated cancers in the Ontario refinery and petrochemical sector.

Asbestos has been widely used in the refinery and petrochemical sector. Mesothelioma has occurred among maintenance employees, and it was hypothesized that mesothelioma is a marker for exposures which might increase lung cancer risk. A death certificate-based case-control study of mesothelioma and lung cancer from 1980 to 1992 was conducted in an Ontario county with a substantial presence of these industries. Each of the 17 men who died of mesothelioma and 424 with lung cancer were matched with controls who died of other causes. The Job and Industry fields on the death certificates were abstracted. Employment as a maintenance worker in the refinery and petrochemical sector was associated with an increased risk of mesothelioma (odds ratio: 24.5; 90% confidence interval 3.1-102). The risk of lung cancer among petrochemical workers, in comparison with all other workers in the county, was 0.88. In an internal comparison of maintenance employees with other blue-collar workers in the refinery and petrochemical sector, the odds ratio for lung cancer was 1.73 (90% confidence interval 0.83-3.6). This finding is consistent with no difference in risk between maintenance and other employees, but it is also compatible with study power being too low to achieve statistical significance. The hypothesis of increased lung cancer risk could be examined more fully with nested case-control studies in existing cohorts. Meanwhile, it would be prudent to reinforce adherence to asbestos control measures in the refinery and petrochemical sector.

Clinical measures, smoking, radon exposure, and risk of lung cancer in uranium miners.

OBJECTIVES: Exposure to the radioactive daughters of radon is associated with increased risk of lung cancer in mining populations. An investigation of incidence of lung cancer following a clinical survey of Ontario uranium miners was undertaken to explore whether risk associated with radon is modified by factors including smoking, radiographic silicosis, clinical symptoms, the results of lung function testing, and the temporal pattern of radon exposure. METHODS: Miners were examined in 1974 by a respiratory questionnaire, tests of lung function, and chest radiography. A random selection of 733 (75%) of the original 973 participants was followed up by linkage to the Ontario Mortality and Cancer Registries. RESULTS: Incidence of lung cancer was increased threefold. Risk of lung cancer among miners who had stopped smoking was half that of men who continued to smoke. There was no interaction between smoking and radon exposure. Men with lung function test results consistent with airways obstruction had an increased risk of lung cancer, even after adjustment for cigarette smoking. There was no association between radiographic silicosis and risk of lung cancer. Lung cancer was associated with exposures to radon daughters accumulated in a time window four to 14 years before diagnosis, but there was little association with exposures incurred earlier than 14 years before diagnosis. Among the men diagnosed with lung cancer, the mean and median dose rates were 2.6 working level months (WLM) a year and 1.8 WLM/year in the four to 14 year exposure window. CONCLUSIONS: Risk of lung cancer associated with radon is modified by dose and time from exposure. Risk can be substantially decreased by stopping smoking.

Effects of different techniques of endotracheal epinephrine administration in pediatric porcine hypoxic-hypercarbic cardiopulmonary arrest.

OBJECTIVE: To compare three endotracheal epinephrine instillation techniques in a pediatric porcine hypoxic-hypercarbic cardiopulmonary arrest model. DESIGN: Prospective, randomized, laboratory comparison of three instillation techniques. SETTING: Large animal research facility at a children's hospital. SUBJECTS: Thirty-six preadolescent anesthetized and paralyzed Yucatan swine (mean weight 10.0 +/- 1.9 kg) with apnea-induced hypoxic and hypercarbic cardiopulmonary arrest. INTERVENTIONS: After 8 mins of cardiopulmonary arrest and 1 min of cardiopulmonary resuscitation (CPR), 500 micrograms (51 +/- 9 micrograms/kg) of radiolabeled endotracheal epinephrine was administered by direct injection (n = 17), injection via feeding catheter (n = 10), or via monitoring lumen built into the sidewall of the endotracheal tube (n = 9). CPR was resumed and continued for 5 mins. If resuscitation occurred, monitoring was continued for 1 hr. Outcome variables included successful resuscitation, pulmonary distribution, heart rate, mean arterial pressure, plasma radiolabeled epinephrine counts, and total plasma epinephrine concentrations. Analysis by Fisher's exact test, one-way analysis of variance and Pearson's phi coefficient was performed. MEASUREMENTS AND MAIN RESULTS: Successful resuscitation occurred in 31% of all pigs with no difference between groups (p = .69). Bilateral distribution occurred in 39% with no difference between groups (p = .25). No correlation was noted between successful resuscitation and distribution (p = .65). HR, mean arterial pressure, plasma radiolabeled epinephrine counts, and total plasma epinephrine concentrations showed significant changes over time within groups, but no difference between groups at any time point. Adherence of the epinephrine dose to the endotracheal tube was < or = 1.5% in all cases. CONCLUSIONS: Instillation of 50 micrograms/kg of endotracheal epinephrine by three different techniques during pediatric porcine asphyxial arrest does not affect resuscitation rate, pulmonary distribution, hemodynamic response, or plasma exogenous and total epinephrine concentrations. No correlation was found between successful resuscitation and bilateral distribution. Therefore, currently recommended cumbersome endotracheal epinephrine instillation techniques may offer no resuscitation advantage over commonly used direct injection in this setting.

Aspartate-induced neuronal necrosis in infant mice: protective effect of carbohydrate and insulin.

Infant mice given large doses of glutamate or aspartate develop hypothalamic neuronal necrosis. Studies by others demonstrated that simultaneous administration of carbohydrate or prior injection with insulin markedly decreased glutamate-induced neuronal damage. We investigated whether carbohydrate and insulin exert a similar protective effect against aspartate-induced neuronal necrosis. Eight-day-old mice administered aspartate at 750 and 1000 mg/kg body weight developed neuronal necrosis (45.9 +/- 7.2 and 80.8 +/- 17.3 necrotic neurons/section, respectively). When carbohydrate (1 g/kg body weight) was administered simultaneously no lesions were detected in mice administered 750 mg/kg body weight aspartate, while 30.1 +/- 14.2 necrotic neurons/section were noted at 1000 mg aspartate/kg body weight. Mice administered 1000 mg/kg body weight aspartate with prior injection of insulin had 28.4 +/- 12.6 necrotic neurons/section, while 4.2 +/- 1.4 necrotic neurons/section were noted in insulin treated mice given 750 mg aspartate/kg body weight. Carbohydrate and insulin treatments has only minimal effects on plasma aspartate concentrations.

Correlation of aspartate dose, plasma dicarboxylic amino acid concentration, and neuronal necrosis in infant mice.

Eight-day-old mice were administered aspartate at 0, 1.88, 3.76, 4.89, 5.64 and 7.52 mmol/kg body wt and the degree and extent of neuronal necrosis determined. In addition, plasma aspartate and glutamate concentrations were determined at each aspartate dose. Animals administered aspartate at 0, 1.88 and 3.76 mmol/kg body wt did not develop neuronal necrosis. Hypothalamic neuronal necrosis (7.33 +/- 1.52 necrotic neurons/section of maximal damage) was found in 3 of 10 animals administered aspartate at 4.89 mmol/kg body wt. The extent of neuronal necrosis was proportional to dose once a neurotoxic dose of aspartate was reached. All 12 animals administered aspartate at 5.64 mmol/kg body wt developed lesions (49.5 +/- 7.2 necrotic neurons/section of maximal damage). Similarly, all 18 mice administered aspartate at 7.52 mmol/kg developed hypothalamic lesions (80.8 +/- 17.8 necrotic neurons/section of maximal damage). Infant mice administered the highest dose of aspartate not producing neuronal necrosis (3.76 mmol/kg) had a mean (+/- S.D.) peak plasma aspartate concentration of 87 +/- 23 mumol/dl and a mean peak plasma glutamate concentration of 64 +/- 22 mumol/dl. Thus, the toxic threshold for these amino acids must be greater than those values.

Comparison of large unilamellar vesicles prepared by a petroleum ether vaporization method with multilamellar vesicles: ESR, diffusion and entrapment analyses.

Large unilamellar vesicles, prepared by a petroleum ether vaporization method, were compared to multilamellar vesicles with respect to a number of physical and functional properties. Rotational correlation time approximations, derived from ESR spectra of both hydrophilic (3-doxyl cholestane) and hydrophobic (3-doxyl androstanol) steroid spin probes, indicated similar molecular packing of lipids in bilayers of multilamellar and large unilamellar liposomes. Light scattering measurements demonstrated a reduction in apparent absorbance of large unilamellar vesicles, suggesting loss of multilamellar structure which was confirmed by electron microscopy. Furthermore, large unilamellar vesicles exhibited enhanced passive diffusion rates of small solutes, releasing a greater percentage of their contents within 90 min than multilamellar vesicles, and reflecting the less restricted diffusion of a unilamellar system. The volume trapping capacity of large unilamellar vesicles far exceeded that of multilamellar liposomes, except in the presence of a trapped protein, soy bean trypsin inhibitor, which reduced the volume of the aqueous compartments of large unilamellar vesicles. Finally, measurement of vesicle diameters from electron micrographs of large unilamellar vesicles showed a vesicle size distribution predominantly in the range of 0.1--0.4 micron with a mean diameter of 0.21 micron.