Melatonin Ingestion Prevents Liver Damage and Improves Biomarkers of Renal Function Following a Maximal Exercise.

Background: While the promotion of the beneficial effects of melatonin (MEL) ingestion on the modulation of oxidative stress is widespread, less attention is given to the biological influence that it could exert on the results of hematology and clinical chemistry parameters. This study was undertaken to assess the effects of acute MEL ingestion on these parameters during a maximal running exercise. Methods: In double blind randomized design, 12 professional soccer players [age: 17.54 ± 0.78 yrs, body mass: 70.31 ± 3.86 kg, body height: 1.8 ± 0.08 m; maximal aerobic speed (MAS): 16.85 ± 0.63 km/h; mean ± standard deviation], all males, performed a diurnal (17:00 h ± 30 h) running exercise test (RET) at 100% of their MAS following either MEL or placebo ingestion. Blood samples were obtained at rest and following the RET. Results: Compared to placebo, MEL intake decreased post-exercise biomarkers of liver damage (aspartate aminotransferase, p<0.001; alanine aminotransferase, p<0.001; gamma-glutamyltransferase; p<0.05) and improved post-exercise renal function markers (i.e., creatinine, p<0.001). However, lipid profile, glucose, lactate and leukocyte were not affected by MEL ingestion. Regarding the time to exhaustion, no difference was found between MEL (362.46 ± 42.06 s) and PLA (374.54 ± 57.97 s) conditions. Conclusion: The results of this investigation clearly attest that MEL ingestion before a maximal running exercise might protect athletes from liver damage and perturbation in renal function biomarkers. However, this study comprises an acute MEL supplementation and no assessment on chronic effects or circadian rhythm the day before was done.

Effect of nocturnal melatonin intake on cellular damage and recovery from repeated sprint performance during an intensive training schedule.

An optimal recovery between training sessions is of similar if not greater importance as the training content and program of the training, itself. One of the most used strategies for improving recovery is the ingestion of supplements. The present study aimed to evaluate the effect of 5 mg oral melatonin supplementation on the recovery from repeated sprint (RSA) of performance and biochemical responses (i.e. oxidative stress, leukocytosis cellular damage) after an intensive training camp (TC). Twenty soccer players performed an RSA test before and after an intensive six-day TC associated with nocturnal melatonin (n = 10) or placebo (n = 10) ingestion. Resting and post-RSA test blood samples were obtained before and after the TC. Compared to placebo, melatonin intake decreased resting oxidative stress markers (i.e, advanced oxidation protein products), leukocytosis (i.e. white blood cells (WBC), neutrophils (NE)) and biomarkers of cellular damage (i.e. creatine kinase (CK)). It also lowered post-exercise leukocytosis (i.e. WBC, NE, lymphocytes (LY), monocytes (MO)) and biomarkers of cellular damage (i.e. CK, aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT)) and raised the activity of the main antioxidant enzymes (i.e. glutathione peroxidase (GPx), glutathione reductase (GR)). In addition, compared to placebo, melatonin reduced the deterioration of the best and total time during the RSA test after the TC. In conclusion, nocturnal melatonin supplementation during an intensive TC alleviated oxidative stress, leukocytosis and cellular damage and improved recovery of RSA performance in soccer players.

Effect of freezing-thawing process and quercetin on human sperm survival and DNA integrity.

We aimed in the first part of our work to study the effect of cryopreservation on the human sperm DNA integrity and the activation of caspase 3, the main apoptosis indicator. In the second part, we were interested in testing the effect of quercetin, as an antioxidant, in preventing sperm damage during the freeze-thawing process. Seventeen semen samples were obtained from 17 men recruited for infertility investigations. Liquefied sperm was cryopreserved using spermfreeze®. Nine of the used samples were divided into two aliquots; the first one was cryopreserved with spermfreeze only (control) and the second one was cryopreserved with spermfreeze supplemented with quercetin to a final concentration of 50 µM. Sperm motility and viability were assessed according to WHO criteria. We used TUNEL assay and the Oxy DNA assay to assess sperm DNA integrity. Activated caspase 3 levels were measured in spermatozoa using fluorescein-labeled inhibitor of caspase (FLICA). Cryopreservation led to a significant increase in sperm DNA fragmentation, DNA oxidation and caspase 3 activation (p<0.01). Supplementation of the cryopreservation medium with quercetrin induced a significant improvement in post thaw sperm parameters, compared to those of control, regarding sperm motility (p=0.007), viability (p=0.008) and DNA integrity (p=0.02); however, it had no effect on caspase 3 activation (p=0.3). We conclude that oxidative stress plays a major role in inducing sperm cryodamage but implication of apoptosis in this impairment requires further investigations. Quercetin could have protective effect during cryopreservation but further research is needed to confirm this effect.

Sperm DNA fragmentation and oxidation are independent of malondialdheyde.

BACKGROUND: There is clinical evidence to show that sperm DNA damage could be a marker of sperm quality and extensive data exist on the relationship between DNA damage and male fertility status. Detecting such damage in sperm could provide new elements besides semen parameters in diagnosing male infertility. We aimed to assess sperm DNA fragmentation and oxidation and to study the association between these two markers, routine semen parameters and malondialdehyde formation. METHODS: Semen samples from 55 men attending the Histology-Embryology Laboratory of Sfax Faculty of Medicine, Tunisia, for semen investigations were analysed for sperm DNA fragmentation and oxidation using flow cytometry. The Sperm was also assessed spectrophotometrically for malondialdehyde formation. RESULTS: Within the studied group, 21 patients were nonasthenozoospermic (sperm motility ≥ 50%) and 34 patients were considered asthenozoospermic (sperm motility < 50%). A positive correlation was found between sperm DNA fragmentation and oxidation (p = 0.01; r = 0.33). We also found a negative correlation between sperm DNA fragmentation and some sperm parameters: total motility (p = 0.001; r = -0.43), rapid progressive motility (type a motility) (p = 0.04; r = -0.27), slow progressive motility (type b motility) (p = 0.03; r = -0.28), and vitality (p < 0.001; r = -0.65). Sperm DNA fragmentation was positively correlated with coiled tail (p = 0.01; r = 0.34). The two parameters that were found to be correlated with oxidative DNA damage were leucocytes concentrations (p = 0.01; r = 0.38) and broken neck (p = 0.02; r = 0.29). Sperm MDA levels were negatively correlated with sperm concentration (p < 0.001; r = -0.57), total motility (p = 0.01; r = -0.35) and type a motility (p = 0.03; r = -0.32); but not correlated with DNA fragmentation and DNA oxidation. CONCLUSIONS: Our results support the evidence that oxidative stress plays a key role in inducing DNA damage; but nuclear alterations and malondialdehyde don't seem to be synchronous.

The same genetic defect in three Tunisian families with Bernard Soulier syndrome: a probable founder Stop mutation in GPIbß.

GPIbα, GPIbß, and GPIX are three candidate genes for a rare genetic bleeding disorder named Bernard Soulier syndrome (BSS). These genes are unique in the genome and encode for glycoprotein subunits of the GPIb-IX complex. Quantitative or qualitative deficiency in this complex is often associated with BSS. Here, we report the novel variant of BSS in which Ser23 of GPIbß is substituted by a Stop codon causing a premature termination of translation, recently described in one family. This genetic defect is revealed in three unrelated BSS patients. The pedigree was determined for two families (F1 and F2) and revealed the homozygosity of the mutation in the two patients and its heterozygosity in parents. In the third family, the patient DNA was heterozygote with the same Ser23 Stop mutation in addition to two missense heterozygote mutations (Asp 51 Gly) and (Ala 55 to Pro). We studied the effect of the Ser23 Stop mutation on the expression of the complex. Our findings confirm that the identified GPIbß mutation is responsible for the BSS phenotype and hampers the GPIb-IX complex to form on the platelets' surface. Regarding the scarcity of the BSS syndrome, the occurrence of the same mutation in three unrelated families would suggest a BSS founder mutation in Tunisia.

Bernard-Soulier syndrome: novel nonsense mutation in GPIbbeta gene affecting GPIb-IX complex expression.

Bernard-Soulier syndrome (BSS) is a rare autosomal recessive genetic disorder characterized by thrombocytopenia, circulating giant platelets, and prolonged bleeding time. BSS is explained by a defect in primary hemostasis owing to quantitative or qualitative defect in the GPIb-IX-V complex, composed of four subunits: GPIbalpha, GPIbbeta, GPIX, and GPV. In this study, we report a novel GPIbbeta defect in a Tunisian family, in which Serine 23 is substituted by a Stop codon causing a premature termination of translation. This defect was homozygous in the BSS patient and heterozygote in both the parents and sisters of the patient. We studied the effect of this mutation on the expression of the GPIb-IX complex by western blot, flow cytometry, and confocal microscopy: GPIbalpha and GPIX were absent on the surface of platelets, whereas they were present in the cytoplasm. These results led to conclude that the novel Ser 23 Stop mutation in GPIbbeta is responsible of BSS in the studied family and hampers the complex to form on the platelets surface.

Human p53 induces cell death and downregulates thioredoxin expression in Saccharomyces cerevisiae.

The p53 tumour suppressor protein has a crucial role in controlling cell cycle and apoptosis in human cells and its inactivation by selective point mutations is associated with human cancers. Here we show that overexpression of the human wild-type (wt) p53 in Saccharomyces cerevisiae completely inhibits yeast growth under minimal media conditions. In contrast, the R248W 'hot spot' p53 mutant (one of the most frequent p53 mutations encountered in human cancers) does not impair yeast growth. Moreover, we report, for the first time, that the human wt p53 induces yeast cell death with characteristic markers of apoptosis: exposure of phosphatidylserine and DNA strand cleavage as shown by Annexin V staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling assay, respectively. In addition, p53 also has an impact on the expression of yeast genes. Using differential display and Northern blot analysis, we demonstrated that human wt p53 expression in yeast leads to gene repression of thioredoxin (TRX1/2), a highly conserved multifunctional antioxidative and antiapoptotic protein family. Accordingly, we demonstrated that reactive oxygen species (ROS) are highly produced in p53 yeast induced cell death as shown by dihydrorhodamine 123 staining. These results suggest that the generation of ROS is a key event in p53 yeast induced cell death.

[A programmed autologous transfusion. A study of 47 patients]. / La transfusion autologue programmée. Etude à propos de 47 patients.

From December 1994 to January 2002, 44 among the 47 patients proposed have been integrated in the protocol of programed autologous transfusion. 18 patients were belonged to the male sex and 26 others belonged to the female one. The average age was 53.2 years (range 15-82 years old). 39 among the patients admitted in the protocol had an orthopaedic pathology. The protocol has associated the teams of surgery, of anesthesia and of transfusion and has occurred in the respect of the regulation (circular 91/2000). The blood taking have led to a significant modification of the hemoglobin rate (average decrease of 2 g/100 ml), of hematocrit (average decrease of 6.1%) and of the rate of platelets (average increase of 29,324 platelets/mm3). On the other hand, a transfusional complement by the concentrated homologous red corpuscles was necessary for 2 patients (2/40).