Are non-allergenic environmental factors important in asthma?

OBJECTIVE: To review the roles of viral respiratory tract infections, environmental tobacco smoke and air pollution in asthma. DATA SOURCES: MEDLINE (1992-1995) searches were conducted for publications on asthma, environmental tobacco smoke, ozone, nitrogen dioxide and particulates. STUDY SELECTION: Representative original experimental and epidemiological studies and reviews of viral infections in asthma. DATA SYNTHESIS: Respiratory virus infections are the most common and important trigger of asthma attacks in children and probably also in adults. Their role in promoting development of asthma is not so clear. Exposure to environmental tobacco smoke is almost certainly responsible for some cases of childhood asthma, and can also trigger symptoms of bronchoconstriction in adults with asthma. Exposure to ozone or nitrogen dioxide is associated with symptoms, impaired lung function, bronchial hyperresponsiveness and hospital presentations for asthma. These pollutants may also act as cofactors in the development of allergen-specific bronchial hyperresponsiveness. CONCLUSIONS: Research on preventing upper respiratory viral infections may reduce asthma morbidity. The move to non-smoking workplaces is welcome, but new interventions are needed to prevent young women taking up smoking and subsequently exposing their children. The ambient air quality guideline for ozone should be revised and a health-based guideline for respirable particulates introduced.     

Lysogeny of blue-green alga Plectonema boryanum by long tailed virus

Lysogeny and its induction with mitomycin C by the long tailed virus is reported. The active virus was liberated in the medium during the growth period and ability of trichomes to produce virus was not reduced by treatment with EDTA.     

Alcohol use disorders and neuropsychological functioning in first-year undergraduates

The relation between alcohol use disorders and neuropsychological functioning was examined in 489 first-year undergraduates, approximately half of whom had a history of alcoholism in their biological fathers. Factor analyses of 17 neuropsychological tests and subtests produced the following 5 factors that were the basis of subsequent analyses: Language/Verbal Memory, Visuospatial Ability, Motor Speed, Booklet Category Performance, and Attention. Participants with alcohol use disorders showed deficits in visuospatial ability. Those who had alcohol dependence showed deficits in both visuospatial ability and motor speed relative to participants who abused alcohol. The differences in neuropsychological functioning remained even after several potential confounding variables were controlled statistically. Results suggest that alcohol use disorders in first-year college students are associated with deficits in neuropsychological measures that are not attributable to several potential third-variable explanations.     

Programmed cell death in the Müllerian duct induced by Müllerian inhibiting substance

The importance of a secretory product of the fetal testis, Müllerian Inhibiting Substance, in determining the fate of the Müllerian duct in the developing male fetus has been well documented. The present investigation has examined the mechanism of action of Müllerian Inhibiting Substance in the male rat fetus during the course of Müllerian duct degeneration. The action of Müllerian Inhibiting Substance mimics the general morphogenetic phenomenon of "programmed cell death," although important diferences were found compared to the majority of other studies of cell death. The initial morphological event in the degenerating Müllerian duct is an increase in lysosomes within the duct cells. Following loss of polarity and orientation, the duct cells are subsequently removed by invading macrophages from the surrounding mesenchyme. Concommitant with the differentiation of these macrophages, the adjacent mesenchyme assumes a characteristic whorled pattern around the degenerating Müllerian duct. Cytochemical localization of acid phosphatase confirmed the presence of newly formed lysosomes within the Müllerian duct cells and subsequently within the cytoplasm of the invading macrophages.     

Neomycin toxicity revisited

Nephrotoxicity and ototoxicity represent the most hazardous side effects of the clincial use of neomycin sulfate. Despite therapeutic restriction of the latter compound to topical, irrigant, and bowel sterilization use, serious toxicity is still encountered. A 69-year-old patient was recently treated by us for acute renal failure and total deafness induced as a result of intermittent seven-day lavage of a surgical cavity with neomycin. Peritoneal dialysis reduced the serum concentration of the antibiotic and promoted complete recovery of renal function. The patient, however, remained deaf. This case serves as a reminder that neomycin can be absorbed systemically following its use as an irrigant solution. In such cases, it may produce an unsuspected form of "high output" renal failure and concomitant hearing loss. The renal failure is usually reveesible, but the hearing loss is frequently permanent.     

Quantitative and qualitative analysis of the extracellular matrix protein, laminin, in Hirschsprung's disease

Previous immunohistochemical studies have shown an abnormal distribution of extracellular matrix (ECM) proteins, including laminin, in the smooth muscle layer of muscularis externa in Hirschsprung's disease (HD) bowel. These findings supported the hypothesis that an abnormal ECM microenvironment may be responsible for the failure of migration and/or development of the neural crest cells in the gut in HD. In order to determine the cause of the abnormality in laminin distribution, solid-phase enzyme-linked immunosorbent assays and immunoblots were used to quantitate the ECM protein laminin and characterize its subunits, respectively, in extracts of the dissected smooth muscle layer of the muscularis externa. In the aganglionic bowel, laminin (median concentration, 32.4 ng/mg of tissue) was found to be present in significantly greater quantity than in both the normoganglionic bowel of the same specimen (median, 17.2 ng/mg, P less than or equal to .05) and the normal bowel of age-matched controls (median, 9.7 ng/mg, P less than or equal to .05). Laminin concentration was also found to be significantly higher in normoganglionic HD bowel (median, 17.2 ng/mg) than in age-matched control specimens (median, 10.8 ng/mg, P less than or equal to .05). No difference was observed in the subunit composition of laminin in HD and control extracts analysed by immunoblot after polyacrylamide gel electrophoresis. This study demonstrates a quantitative abnormality of laminin in the bowel in HD, supporting the hypothesis that "abnormal microenvironment" may have a role in the pathogenesis of HD.     

Reduced sensitivity to linguistic context in schizophrenic thought disorder: evidence from on-line monitoring for words in linguistically anomalous sentences

The use of linguistic context in positively thought-disordered (TD) schizophrenics was investigated through examination of their performance on an on-line word-monitoring task. Controls and non-TD schizophrenics took longer to recognize words preceded by linguistic anomalies compared with words in normal sentences. Compared with both other groups, TD schizophrenics showed significantly smaller differences in reaction time, suggesting that they were relatively insensitive to linguistic violations. TD schizophrenics were also less sensitive to linguistic violations in an off-line version of the task, in which they judged whether the sentences "made sense." Finally, these participants produced more errors on a verbal fluency task than did non-TD schizophrenics or normal controls. These findings are consistent with the theory that schizophrenic thought disorder arises from a deficit in the use of linguistic context to process and produce speech.