Evaluation of three substitutes for Percoll in sperm isolation by density gradient centrifugation

Silane-coated silica particle solutions (ISolate(TM) and PureSperm)TM)) and iodixanol (OptiPrep(TM)) were compared to polyvinylpyrrolidone (PVP)-coated silica particles (Percoll(TM)) in their efficacy to recover spermatozoa by gradient centrifugation for use in assisted reproductive procedures. Efficacy was assessed in terms of percentages of sperm recovery, sperm vitality and motility, normal sperm morphology and normal sperm chromatin condensation. No significant difference was found in the recovery of spermatozoa for men with both normal sperm counts and oligozoospermia, between PVP-coated and silane-coated particle solutions. Iodixanol had significantly lower sperm recovery compared to the other products. Sperm vitality, progressive motility, normal morphology and normal chromatin condensation did not differ significantly between any of the sperm isolation products.      

Protective cytotoxic T lymphocyte responses against paramyxoviruses induced by epitope-based DNA vaccines: involvement of IFN-gamma

Plasmid DNA vectors have been constructed with minigenes encoding a single cytotoxic T lymphocyte (CTL) epitope from either the M2 protein of respiratory syncytial virus (RSV) or from the nucleoprotein of measles virus (MV) with or without a signal sequence (also called secretory or leader sequence). Following intradermal immunization, plasmids in which the CTL epitopes were expressed in-frame with the signal sequence were more effective at inducing peptide- and virus- specific CTL responses than plasmids expressing CTL epitopes without the signal sequence. This immunization resulted in protection against MV-induced encephalitis and a significant reduction in viral load following RSV challenge. The reduction of viral load following RSV challenge was abrogated by prior injection with anti-IFN-gamma antibodies. These results highlight the ability of epitope-based DNA immunization to induce protective immune responses to well-defined epitopes and indicate the potential of this approach for the development of vaccines against infectious diseases.      

The relationship of myocarditis to dilated cardiomyopathy

Three patients with congestive cardiomyopathy are reported inwhom high neutralizing antibody titres to Coxsackie B viruseswere detected. At post-mortem examination, all three had histologicallydemonstrable chronic inflammation of the myocardium. The heartsof ten patients dying in cardiac failure due to other causesshowed no comparable inflammatory infiltration. This providesfurther evidence that Coxsackie B viral myocarditis is involvedin the pathogenesis of some cases of dilated cardiomyopathy. One patient also had pulmonary veno-occlusive disease. Thishas been reported in association with myocarditis once previouslyin an infant. A viral aetiology has been postulated. It seemslikely in this patient to have also been due to a CoxsackieB virus.     

The Translocation of Inhaled Silicon Dioxide: An Empirically Derived Compartmental Model

The Translocation of Inhaled Silicon Dioxide: An EmpiricallyDerived Compartmental Model. VACEK, P. M., HEMENWAY, D. R.,ABSHER, M. P., AND GOODWIN, G. D. (1991). Fundam. Appl Toxicol.17, 614–626. The movement of inhaled silicon dioxide particleswas studied by measuring the amounts in alveolar fluid and cells,lung tissue, and lymphoid tissue during the 6 months followingshort-term aerosol exposure of Fischer 344 rats. A variety offirst-order compartmental models were fit to data from nineexposure experiments to identify the most feasible biologicpathways for the transfer of material among these sites andout of the body. A multivariate least-squares approach was usedto simultaneously fit the data from several compartments. Theresults indicate that transfer between alveolar cells and lungtissue occurs in both directions, suggesting that silica canreenter the alveolar space from the lung tissue. This featurehas not been included in previously published models. The resultsalso indicate that transfer from lung tissue to the mediastinallymph nodes and thymus is indirect; there are one or more unidentifiedextrapulmonary compartments that receive silica from the lung.Rates of transfer among compartments were dependent on mineraltype (quartz or cristobalite), heat treatment, and exposuredose. There was no evidence for direct clearance from the alveolarspace via the tracheobronchial tract.     

Two decades of atrial tumour

We have reported 19 patients with atrial tumour. The long follow-up(5–19 years, mean 10 years) of the 17 patients with leftatrial myxoma has been described. No patient showed evidenceof recurrence of the tumour, although three patients have unexplainedshadows—probably artifactual—on echocardiography.The limitations ofechocardiography and importance of clinicalindicators are stressed. One patient had a rhabdomyosarcoma of the left atrium and diedone year after operation. Certain features differentiated thispatient from those with myxoma. It is concluded that true atrial myxoma does not metastasize.Reports in the literature of metastasizing left atrial myxomaprobably refer to malignant tumours simulating myxoma. Variationsfrom the typical clinical and haemodynamic picture of atrialmyxoma should arouse suspicion of malignancy. Careful microscopicexamination of the tumour is essential.     

Anicteric hepatoxicity: a potential health risk of occupational exposures in Nigerian petroleum oil refining and distribution industry

Background

Literature abounds linking one’s job to certain unpalatable health outcomes. Since exposures to hazardous conditions in industrial environments often results in sundry health effects among workers, we embarked on this study to investigate the hepatic health effects of occupational activities in the petroleum refining and distribution industry.

Method

Biochemical markers of liver functions were assayed in plasma, using Reflotron dry chemistry spectrophotometric system. The study was conducted on randomly selected workers of Port Harcourt Refining Company (PHRC) and Pipelines and Petroleum Product Marketing Company (PPMC) both in Alesa-Eleme near Port Harcourt, Nigeria, as well as non-oil work civil servants serving as control subjects.

Result and conclusion

Results showed that, bilirubin ranged 0.3-1.6 mg/dl with a mean of 0.66±0.20mg/dl among the oil workers as against 0.5-1.00mg/dl with a mean of 0.58±0.13mg/dl in non-oil workers, Alkaline phosphatase ranged 50.00-296.00u/l (mean: 126.21±39.49u/l) in oil workers as against 40.20-111u/l (mean: 66.83±18.54u/l) for non-oil workers, Aspartic transaminases (AST) ranged 5.80-140.20u/l (mean: 21.81±11.49u/l) in oil workers against 18.00-44.00u/l (mean: 26.89±6.99u/l) for non-oil workers, while Alanine transaminases (ALT) ranged 4.90-86.00u/l (mean: 22.14±11.28u/l) in oil workers as against 10.00-86.60u/l (mean: 22.30±10.22u/l) for the non-oil workers. A close study of the results revealed that although the mean values for all the studied parameters were still within the parametric reference ranges, however, relative to the referents, there were significant increases (P<0.05) in plasma bilirubin (though anicteric) and alkaline phosphatase that was not matched with a corresponding increase in the plasma transaminases, suggesting a possibility that toxic anicteric hepatoxicity is part of the potential health effects of sundry exposures in the Nigeria petroleum oil refining and distribution industry. Gender differentiation data showed that though the mean values for the parameters were higher in males than females, the increases were not significant in most cases (P>0.05), whereas data for age and exposure period classifications revealed that irrespective of the age of the worker, the effects are likely to start after the first five years, manifesting fully after the first decade of occupational exposures. Thus, an update of industrial/occupational health measures is necessary for a safer and healthier work environment.