Study of mitochondrial membrane potential, reactive oxygen species, DNA fragmentation and cell viability by flow cytometry in human sperm.

BACKGROUND: Sperm cell death appears to be a cause of male infertility. The objective of this study was to determine the most reliable method for the evaluation of sperm quality in semen samples during sperm preparation for IVF. METHODS: Conventional analysis of semen samples was compared with several cytofluorometric methods detecting death-associated changes. Neat semen from infertile patients and sperm prepared by PureSperm gradient were studied by conventional microscopy and analysed for mitochondrial membrane potential (Delta Psi(m)), generation of reactive oxygen species, DNA fragmentation and cell viability. RESULTS: In neat semen, a positive correlation was found between the percentage of Delta Psi(m)(high) sperm cells and standard semen parameters (concentration/motility). Sperm cells depicting Delta Psi(m)(high) and cells with low DNA fragmentation displayed high fertilization rate after IVF. The only changes that could be detected in prepared sperm were changes in Delta Psi(m), with Delta Psi(m)(high) sperm positively correlated with forward motility and also with high fertilization rates after IVF. CONCLUSION: Analysis of mitochondrial membrane potential is the most sensitive test by which to determine sperm quality. These findings promise development of a test that may help to predict successful IVF.

Protective effects of cyclosporin A from endotoxin-induced myocardial dysfunction and apoptosis in rats.

Myocardial depression can be demonstrated following administration of endotoxin. Proposed mechanisms of endotoxin-induced myocardial dysfunction include the release of proinflammatory mediators, focal myocardial ischemia, and the presence of activated leukocytes within the myocardium. Recently, myocardial caspase activation and mitochondria-related apoptotic events (i.e., release of cytochrome c) were demonstrated in the failing septic heart. Here, we tested the hypothesis that immunosuppressors, cyclosporin A and tacrolimus (FK 506), would improve inflammation, heart nuclear apoptosis, and myocardial dysfunction in endotoxin-treated rats. Myocardial contractility was assessed using an isolated heart preparation. Heart leukocyte infiltration was assessed by measurement of heart myeloperoxidase activity. Leukocyte activation was studied using the intravital microscopy of the mesenteric venule. Apoptosis was detected as myocardial DNA fragmentation, downstream caspase activation, and mitochondrial cytochrome c release. Both cyclosporin A and FK 506 reduced heart leukocyte sequestration and venular adhesion in endotoxin-treated rats. Cyclosporin A, which blocks mitochondrial cytochrome c release, was able to reduce endotoxin-induced myocardial end-stage nuclear apoptosis and heart dysfunction, whereas tacrolimus had no such effects. These effects could be related to the unique properties of cyclosporin A to act on mitochondria.

Risk factors for anaemia in patients on prolonged linezolid therapy for chronic osteomyelitis: a case-control study.

OBJECTIVES: The intrinsic properties of the new antibiotic linezolid make it an attractive candidate for the treatment of chronic osteomyelitis. However, data regarding the tolerance of long-term linezolid administration are still lacking. METHODS: The medical charts of patients given linezolid for >4 weeks were retrospectively analysed, especially their haematology. In a case-control study, we compared the respective characteristics of patients who developed anaemia during linezolid therapy and those who did not. RESULTS: Forty-five adults with chronic osteomyelitis received 600 mg linezolid intravenously twice daily for 7 days, and then orally, for a mean total duration of 15.9 weeks (range, 6-36). Anaemia episodes requiring blood transfusion occurred in 13/45 patients (28.9%). Median time from treatment initiation to anaemia onset was 7.4 weeks (range, 4-16). Anaemia was significantly associated with premature linezolid therapy cessation (P = 0.0012). No linezolid-related thrombocytopenia was observed. By univariate analysis, four variables were associated with the occurrence of anaemia: age >58 years, alcohol abuse, diabetes mellitus and low haemoglobin before linezolid treatment. Logistic regression analysis revealed two independent risk factors for anaemia: age >58 years (OR = 20.5, 95% CI 0.69-599; P = 0.0001) and pre-treatment haemoglobin <10.5 g/dL (OR = 16.49, 95% CI 1.06-255; P = 0.04). CONCLUSIONS: Profound anaemia may occur in adult patients with chronic osteomyelitis on prolonged linezolid therapy, and often necessitates linezolid cessation. These patients are likely to be aged >58 years and to have low pre-treatment haemoglobin. The results for the present series might help physicians to identify patients who should not be given long-term linezolid treatment for chronic osteomyelitis.