Enhancement of benzo(a)pyrene metabolism mediated by retinol acetate in cultured human bronchial epithelial-cells

As suggested by animal studies and human epidemiological data, retinoids possess significant cancer chemopreventive activity. Although the majority of studies in this area have focused on the ability of retinoids to prevent the promotion or progression of carcinogenesis, a significant amount of data suggest retinoids can alter initiation events. In the current report, we have evaluated the potential of retinol acetate to modulate benzo(a)pyrene metabolism in low-passage human bronchial epithelial cells in monolayer cultures, Of 16 different cell cultures, benzo(a)pyrene metabolism was increased in 14, decreased in one, and unchanged in one, when retinol acetate was added to the media, In a preliminary study with one of the cell cultures in which retinol acetate significantly enhanced benzo(a)pyrene metabolism, binding of carcinogen metabolites to;DNA was unaffected, Since retinoids are known cancer chemopreventive agents and carcinogen binding to DNA is the key event in the initiation of carcinogenesis, these results suggest that retinoids may decrease carcinogenic risk by increasing the detoxification of procarcinogens such as benzo(a)pyrene ina manner that does not yield a concomitant increase in damage to critical cellular targets such as DNA.     

Review of animal models in carotenoid research

Foods containing provitamin A carotenoids are the primary source of vitamin A in many countries, despite the poor bioavailability of carotenoids. In addition, epidemiologic studies suggest that dietary intake of carotenoids influences the risk for certain types of cancer, cardiovascular disease and other chronic diseases. Although it would be ideal to use humans directly to answer critical questions regarding carotenoid absorption, metabolism and effects on disease progression, appropriate animal models offer many advantages. This paper will review recent progress in the development of animal models with which to study this class of nutrients. Each potential model has strengths and weaknesses. Like humans, gerbils, ferrets and preruminant calves all absorb beta-carotene (betaC) intact, but only gerbils and calves convert betaC to vitamin A with efficiency similar to that of humans. Mice and rats efficiently convert betaC to vitamin A but absorb carotenoids intact only when they are provided in the diet at supraphysiologic levels. Mice, rats and ferrets can be used to study cancer, whereas primates and gerbils are probably more appropriate for studies on biomarkers of heart disease. No one animal model completely mimics human absorption and metabolism of carotenoids; thus the best model must be chosen with consideration of the specific application being studied, characteristics of the model, and the available funding and facilities.     

Information technology and under-served communities

Advances in information technology (IT) and telecommunications offer many potential benefits to Australia's under-served communities. However, there is also a risk that some of these communities will only be further disadvantaged, as IT will not contribute greatly to bringing groups such as the mentally ill and illiterate into the mainstream of the community. However, other under-served groups may experience service improvements. For people who do not have English as their first language, IT developments provide opportunities for cheaper and easier service and information delivery in their own languages. Telemedicine and IT also have the potential to make working in rural areas more attractive. On the other hand, telemedicine may be used as a means to bypass local health service providers, as has happened with other service industries. The health sector, though, is well behind these other industries in adopting IT and telecommunications. The growth of telemedicine projects is one indication that progress is being made, however. Two case studies--of telepsychiatry, and of medical education at Flinders University--provide examples of major Australian successes. The medical workforce implications will involve the overall numbers and mix of practitioners, their geographical distribution, changing professional boundaries and changing skill requirements. The only certain effect is that if IT changes the nature of medical work, large numbers of medical practitioners will need to improve their computer skills and older practitioners will find this most difficult.     

Can involuntary outpatient commitment reduce hospital recidivism?: Findings from a randomized trial with severely mentally ill individuals

OBJECTIVE: The goal of this study was to evaluate the effectiveness of involuntary outpatient commitment in reducing rehospitalizations among individuals with severe mental illnesses. METHOD: Subjects who were hospitalized involuntarily were randomly assigned to be released (N = 135) or to continue under outpatient commitment (N = 129) after hospital discharge and followed for 1 year. Each subject received case management services plus additional outpatient treatment. Outpatient treatment and hospital use data were collected. RESULTS: In bivariate analyses, the control and outpatient commitment groups did not differ significantly in hospital outcomes. However, subjects who underwent sustained periods of outpatient commitment beyond that of the initial court order had approximately 57% fewer readmissions and 20 fewer hospital days than control subjects. Sustained outpatient commitment was shown to be particularly effective for individuals with nonaffective psychotic disorders, reducing hospital readmissions approximately 72% and requiring 28 fewer hospital days. In repeated measures multivariable analyses, the outpatient commitment group had significantly better hospital outcomes, even without considering the total length of court-ordered outpatient commitments. However, in subsequent repeated measures analyses examining the role of outpatient treatment among psychotically disordered individuals, it was also found that sustained outpatient commitment reduced hospital readmissions only when combined with a higher intensity of outpatient treatment. CONCLUSIONS: Outpatient commitment can work to reduce hospital readmissions and total hospital days when court orders are sustained and combined with intensive treatment, particularly for individuals with psychotic disorders. This use of outpatient commitment is not a substitute for intensive treatment; it requires a substantial commitment of treatment resources to be effective.     

An N-linked high-mannose type oligosaccharide, expressed at the major outer membrane protein of Chlamydia trachomatis, mediates attachment and infectivity of the microorganism to HeLa cells.

The structure of the carbohydrate of the 40-kD major outer membrane component of Chlamydia trachomatis and its role in defining infectivity of the organism were investigated. The oligosaccharides were released from the glycoprotein by N-glycanase digestion, coupled to a 2-aminopyridyl residue, and subjected to two-dimensional sugar mapping technique. The major fractions consisted of "high-mannose type" oligosaccharides containing 8-9 mannose residues. Bi- and tri-antennary "complex type" oligosaccharides having terminal galactose were detected as minor components. These oligosaccharides were N-linked and contained no sialic acid. This structural profile is consistent with our previous characterization based on lectin-binding and glycosidase digestion. Functional specificity of identified chlamydial oligosaccharides was analyzed using glycopeptides fractionated from ovalbumin and structurally defined oligosaccharides from other sources. The glycopeptide fraction having high-mannose type oligosaccharide, as compared to those having complex or hybrid-type, showed a stronger inhibitory effect on attachment and infectivity of chlamydial organisms to HeLa cells. Among high-mannose type oligosaccharides, the strongest inhibition was observed with mannose 8 as compared with mannose 6, 7, or 9. These results indicate that a specific high-mannose type oligosaccharide linked to the major outer membrane protein of C. trachomatis mediates attachment and infectivity of the organism to HeLa cells.     

An autoradiographic study of the organization of the efferent connections of the hippocampal formation in the rat.

The efferent connections of the hippocampal formation of the rat have been re-examined autoradiographically following the injection of small quantities of 3H-amino acids (usually 3H-proline) into different parts of Ammon's horn and the adjoining structures. The findings indicate quite clearly that each component of the hippocampal formation has a distinctive pattern of efferent connections and that each component of the fornix system arises from a specific subdivision of the hippocampus or the adjoining cortical fields. Thus, the precommissural fornix has been found to originate solely in fields CA1-3 of the hippocampus proper and from the subiculum; the projection to the anterior nuclear complex of the thalamus arises more posteriorly in the pre- and/or parasubiculum and the postsubicular area; the projection to the mammillary complex which comprises a major part of the descending columns of the fornix has its origin in the dorsal subiculum and the pre- and/or parasubiculum; and finally, the medial cortico-hypothalamic tract arises from the ventral subiculum. The lateral septal nuclei (and the adjoining parts of the posterior septal complex) constitute the only subcortical projection field of the pyramidal cells in fields CA1-3 of Ammon's horn. There is a rostral extension of the pre-commissural fornix to the bed nucleus of the stria terminalis, the nucleus accumbens, the medial and posterior parts of the anterior olfactory nucleus, the taenia tecta, and the infralimbic area, which appears to arise from the temporal part of field CA1 or the adjacent part of the ventral subiculum. The projection of Ammon's horn upon the lateral septal complex shows a high degree of topographic organization (such that different parts of fields CA1 and CA3 project in an ordered manner to different zones within the lateral septal nucleus). The septal projection of "CA2" and field CA3 is bilateral, while that of field CA1 is strictly unilateral. In addition to its subcortical projections, the hippocampus has been found to give rise to a surprisingly extensive series of intracortical association connections. For example, all parts of fields CA1, CA2 and CA3 project to the subiculum, and at least some parts of these fields send fibers to the pre- and parasubiculum, and to the entorhinal perirhinal, retrosplenial and cingulate areas. From the region of the pre- and parasubiculum there is a projection to the entorhinal cortex and the parasubiculum of both sides. That part of the postsubiculum (= dorsal part of the presubiculum) which we have examined has been found to project to the cingulate and retrosplenial areas ipsilaterally, and to the entorhinal cortex and parasubiculum bilaterally.     

Prediction of skating speed with off-ice testing in professional hockey players

Presented at the Sports Physical Therapy Section Team Concept Meeting, December 1991, New Orleans, LA. The purpose of this study was to determine the best off-ice predictors of sprint skating speed in professional ice hockey players. Off-ice functional tests included a 40-yd dash, standing long jump, and vertical jump, as well as isokinetic testing of the quadriceps and hamstrings at speeds of 60 and 180 degrees . Skating speed was determined by a 54.9-m sprint skate test. Nine professional ice hockey players served as subjects. Skating speed was significantly correlated with vertical jump anaerobic power as determined by the Lewis formula and with several isokinetic power measurements. The single best predictor of skating speed was vertical jump anaerobic power. An even better prediction of skating speed was possible using two isokinetic measurements, the average power of the left quadriceps at 180 degrees (APLQ180) and the average power of the right hamstrings at 60 degrees (APRH60). These measurements may be used to objectively evaluate off-ice training programs designed to enhance speed skating performance. J Orthop Sports Phys Ther 1992;15(2):92-98.