Protection from environmental tobacco smoke in California. The case for a smoke-free workplace.

OBJECTIVE--To determine the extent of exposure of nonsmoking indoor workers to environmental tobacco smoke (ETS) according to type of work-site smoking policy, work area, workplace size, and demographic characteristics. DESIGN AND PARTICIPANTS--Participants included 7162 adult, nonsmoking, indoor workers who were interviewed as part of the 1990 California Tobacco Survey. Respondents were asked whether anyone had smoked in their work area within the past 2 weeks. RESULTS--An estimated 2.2 million California nonsmokers were exposed to tobacco smoke at indoor work sites in 1990. Nonsmoker exposure to ETS was 9.3% for those working in a smoke-free worksite, 23.2% for those working where there was only a work-area restriction, 46.7% for those working where there was a policy that did not include the work area, and 51.4% for those working where there was no work-site smoking policy. After adjustment for type of work area (eg, office, open area), workplace size, and demographic factors, it was determined that nonsmokers working where there was only a work-area ban were 2.8 times more likely to be exposed to ETS than those working in a smoke-free work site. In workplaces with no policy or a policy not covering the work area, nonsmokers were over eight times more likely to be exposed to ETS than those who worked in a smoke-free work site. Nonsmokers who were 18 to 24 years of age, male, or Hispanic, and those with less than a high school education had more exposure to ETS. CONCLUSION--These results indicate that adequate protection of nonsmokers from ETS exposure requires a smoke-free work site.     

Acute intracranial hemorrhage secondary to thrombocytopenia: CT appearances unaffected by absence of clot retraction.

PURPOSETo describe the in vivo CT appearance of acute intracerebral blood clots formed from anemic platelet-depleted blood.METHODSThree patients with intracerebral hemorrhage secondary only to thrombocytopenia were examined with CT within 2 1/2 hours after the onset of clinical symptoms.RESULTSThere were no unusual CT features found in the intracerebral hemorrhages of patients with only thrombocytopenia. Specifically, a hyperdense zone(s) surrounded by areas of decreased density was identified.CONCLUSIONClot retraction (which cannot occur in patients with severe thrombocytopenia) is not necessary for the CT appearance of acute intracerebral hemorrhage.     

Role of nucleotide pyrophosphatase in enflurane-induced reduction of UDP-glucuronic acid concentration in mouse liver

Because hepatic UDP-glucuronic acid levels decrease upon exposure to volatile anesthetics, the present study was designed to determine the mechanism by which enflurane decreases UDP-glucuronic acid in mice by measuring the concentrations of intermediates and the activities of enzymes in the UDP-glucuronic acid pathway. UDP-glucuronic acid concentrations were decreased by 40% in both male and female mice after 10 min of enflurane-induced narcosis. Concentration of UDP-glucose and the activities of diethylstilbestrol UDP-glucuronosyltransferase and UDP-glucose dehydrogenase were not affected by enflurane treatment. In contrast, nucleotide pyrophophatase activity was increased approximately 50% in both sexes. Thus, the decrease in hepatic UDP-glucuronic acid upon exposure of mice to enflurane is probably due to increased degradation by nucleotide pyrophosphatase.     

Impact of clinical history on fracture detection with radiography

The effect of knowledge of localizing symptoms and signs in the detection of fractures was studied. Forty radiographs of the extremities were examined twice by seven radiologists; the sessions were separated by 4 months. In 26 cases, a subtle fracture was present; 14 cases were normal. In half of the cases at each session, the precise location of pain, tenderness, or swelling was provided. The observer was asked to determine if the case was normal or abnormal (provide the exact location of the fracture) and to indicate the degree of confidence in the diagnosis. Responses were converted to a numeric scale for analysis. Analysis of receiver operator characteristic parameters indicates that clues regarding location of trauma facilitate detection of fractures. The improvement is based largely on an increased true-positive rate without an increased false-positive rate, regardless of the decision criteria of the radiologist (overall willingness to "overread" or "underread"). This has direct clinical applicability and reinforces the plea of radiologists for precise clinical information.     

Protection from pathogenic SIV challenge using multigenic DNA vaccines

To assess DNA immunization as a strategy for protecting against HIV infection in humans, we utilized SIVmne infection of Macaca fascicularis as a vaccine challenge model with moderate pathogenic potential. We compared the efficacy of DNA immunization alone and in combination with subunit protein boosts. All of the structural and regulatory genes of SIVmne clone 8 were cloned into mammalian expression vectors under the control of the CMV IE-1 promoter. Eight M. fascicularis were immunized twice with 3 mg of plasmid DNA divided between two sites; intramuscular and intradermal. Four primed macaques received a further two DNA immunizations at weeks 16-36, while the second group of four were boosted with 250 microg recombinant gp160 plus 250 microg recombinant Gag-Pol particles formulated in MF-59 adjuvant. Half of the controls received four immunizations of vector DNA; half received two vector DNA and two adjuvant immunizations. As expected, humoral immune responses were stronger in the macaques receiving subunit boosts, but responses were sustained in both groups. Significant neutralizing antibody titers to SIVmne were detected in one of the subunit-boosted animals and in none of the DNA-only animals prior to challenge. T-cell proliferative responses to gp160 and to Gag were detected in all immunized animals after three immunizations, and these responses increased after four immunizations. Cytokine profiles in PHA-stimulated PBMC taken on the day of challenge showed trends toward Thl responses in 2/4 macaques in the DNA vaccinated group and in 1/4 of the DNA plus subunit vaccinated macaques; Th2 responses in 3/4 DNA plus subunit-immunized macaques; and Th0 responses in 4/4 controls. In bulk CTL culture, SIV specific lysis was low or undetectable, even after four immunizations. However, stable SIV Gag-Pol- and env-specific T-cell clones (CD3+ CD8+) were isolated after only two DNA immunizations, and Gag-Pol- and Nef-specific CTL lines were isolated on the day of challenge. All animals were challenged at week 38 with SIVmne uncloned stock by the intrarectal route. Based on antibody anamnestic responses (western, ELISA, and neutralizing antibodies) and virus detection methods (co-culture of PBMC and LNMC, nested set PCR- of DNA from PBMC and LNMC, and plasma QC-PCR), there were major differences between the groups in the challenge outcome. Surprisingly, sustained low virus loads were observed only in the DNA group, suggesting that four immunizations with DNA only elicited more effective immune responses than two DNA primes combined with two protein boosts. Multigenic DNA vaccines such as these, bearing all structural and regulatory genes, show significant promise and may be a safe alternative to live-attenuated vaccines.