Effect of Percoll wash on sperm motion parameters and subsequent fertility in intrauterine insemination cycles

Purpose This study examined sperm motion parameters as measured by computerized automated semen analysis before and after a Percoll wash and determined if differences in any parameter were correlated with fertility subsequent to intrauterine insemination (IUI).Results Total motile sperm decreased following the washing procedure from 79.0 ± 9.0 to 37.2 ± 7.6 million sperm. Motility increased from a mean of 43.4% to 61.7% (P<0.001). Other motility parameters also changed significantly (P<0.001) as follows: curvilinear velocity (VCL), 43.4 to 61.7 m/s; straight-line velocity (VSL), 21.3 to 26.7 m/s; linearity 53.1 to 45.2%; lateral head displacement (ALH), 2.97 to 3.94 m. Similar changes occurred following a swim-up preparation, although changes in mean motility, VCL, and ALH were significantly greater when compared to Percoll. The postwash changes were not accounted for merely by time lapse in preparation since reanalyzed untreated controls did not show the same changes in motion parameters. Prewash linearity in those specimens which resulted in pregnancies was greater than in those which did not (P=0.28). No other significant differences in pre-or post-Percoll washed sperm motion parameters were found between pregnant vs nonfertile cycles.Conclusion Following Percoll wash all CASA-generated motility parameters were significantly altered, but there was little association between these parameters and pregnancy achieved in IUI cycles.Presented at the 50th Annual Meeting of the American Fertility Society, San Antonio, Texas, November 5–10, 1994.     

Excitatory amino acid release from astrocytes during energy failure by reversal of sodium-dependent uptake

Non-synaptic release may be the major route of excitatory amino acid (EAA) efflux during cerebral ischemia. Possible routes of non-synaptic release include non-specific anion channels, reversal of Na⁺-, CI^?-, or Ca²⁺-dependent uptake, and cell lysis. In the present study we employ a novel approach to show reversal of Na⁺-dependent uptake as a major route of EAA efflux from astrocyte cultures under conditions of energy failure. Primary rat astrocyte cultures were subjected to combined blockade of glycolytic and oxidative metabolism after incubation with [³H]-D-aspartate (D-ASP). Energy failure produced an efflux of D-ASP that was maximal by 90 minutes. The efflux over this period was reduced by more than 50% in cells that had been pre-loaded with PDC (L-transpyrrolidine-2,4-dicarboxylic acid) or TBHA (threo-β-hydroxyaspartic acid), compounds that are competitive inhibitors of Na⁺-dependent glutamate uptake. The effect of pre-loading with the inhibitors was concentration dependent. No effect was seen if the inhibitors were added after induction of energy failure, suggesting that the attenuation of D-ASP efflux resulted from binding of the inhibitors to an intracellular site. These results provide strong evidence that EAA efflux from astrocytes under conditions of energy failure occurs largely through reversal of Na⁺-dependent uptake. © 1995 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

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.