Cellular and biochemical parameters of exercise-induced oxidative stress: relationship with training levels

To better clarify the relationship between physical activity and oxidative stress, we determined the effects of a maximal test in 18 young subjects with different training levels (six professional Athletes and 12 non-agonists (NA)). Redox homeostasis (total antioxidant activity (TAS), vitamin C and glutathione (GSH)), oxidative damage (diene conjugation and hemolysis), lymphocyte cell death and repair systems (apoptosis, micronuclei and Hsp70 expression) were evaluated. We found that agonistic training led to a chronic oxidative insult (high baseline values of oxidized glutathione (GSSG), micronuclei and hemolysis). On the contrary, NA with the lowest level of training frequency showed a well balanced profile at rest, but they were more susceptible to exercise-induced variations (GSSG/GSH and diene increased values), respect to the NA with an higher level of training. As almost all the parameters employed in this study showed inter-individual variations, the GSSG/GSH ratio remains the most sensitive and reliable marker of oxidative stress, accordingly with other data just reported in the literature.     

2-week triple therapy for Helicobacter pylori infection is better than 1-week in clinical practice: a large prospective single-center randomized study

BACKGROUND: Proton pump inhibitor (PPI)-based triple therapies are considered the standard regimens for Helicobacter pylori eradication, but the optimal duration of these regimens is still controversial. The aim of this study was to compare the efficacy of 1-week versus 2-week triple therapies in H. pylori-positive patients. MATERIALS AND METHODS: A total of 486 consecutive H. pylori-positive patients were randomized to receive omeprazole, 20 mg b.i.d., clarithromycin 500 mg b.i.d., and either amoxicillin 1 g b.i.d. or metronidazole 500 mg b.i.d. for 1 or 2 weeks. Upper gastrointestinal endoscopy and histology were performed at entry and 2 months after the end of therapy. H. pylori status was defined according to histology and urea breath test. RESULTS: At intention-to-treat analysis, 2-week therapy with omeprazole, amoxicillin, and clarithromycin achieved a significantly higher eradication rate than 1- or 2-week regimens with metronidazole (70% versus 52%, p = .003, versus 56%, p < .01) and the same therapy for 1-week (70% versus 57%, p = .05). At per-protocol analysis, 2-week therapy with omeprazole, amoxicillin, and clarithromycin showed a significantly higher eradication rate than 1-week of amoxicillin and metronidazole (77% versus 62%; p = .03) but no difference with 1-week same regimen (66%) or 2-week metronidazole and clarithromycin regimen (72%). Compliance and tolerability were good for all regimens. CONCLUSIONS: Two-week therapies, independently of antibiotic combination, lead to a significant increase of H. pylori eradication rate compared to 1-week therapies, with same compliance and tolerability, even if, taking account of low-eradication rates, one must question whether the triple therapy should still be used.     

Issues to consider for preparing ferrets as research subjects in the laboratory

The domestic or European ferret (Mustela putorius furo) has been domesticated for thousands of years. Ferrets have been used for hunting and fur production, as pets, and as models in biomedical research. Despite the relatively small numbers used in the laboratory, ferrets have some unique applications including study of human influenza and severe acute respiratory syndrome (SARS)-associated corona virus. They have served as models for peptic ulcer disease, carotenoid metabolism, cystic fibrosis, and drug emesis screening, among others. Most research ferrets are males, due to estrus-related health problems in females. They may be housed conventionally and are easy to care for when their biology and behavior are understood. Due to the small number of ferret suppliers, animals are often shipped long distances, requiring air transport and intermediate handlers. It is important to minimize shipment stress, especially with weanling and pregnant animals. Additional expertise is required for success with pregnant and whelping ferrets and for rearing of neonates. The animals have specific dietary requirements, and proper nutrition is key. Successful housing requires knowledge of ferret behaviors including social behavior, eating habits, a general inquisitive nature, and a species-typical need to burrow and hide. Regular handling is necessary to maintain well-being. A ferret health care program consists of physical examination, immunization, clinical pathology, and a working knowledge of common ferret diseases. Various research methodologies have been described, from basic procedures such as blood collection to major invasive survival surgery. Ferrets have a distinct niche in biomedical research and are hardy animals that thrive well in the laboratory.     

Antibiotic production improvement in the rare actinomycete Planobispora rosea by selection of mutants resistant to the Aminoglycosides Streptomycin and Gentamycin and to Rifamycin

During a strain improvement program, spontaneous mutants with single or combined resistance to streptomycin (Str^r), gentamycin (Gen^r) or rifamycin (Rif^r) were selected from the industrial strain of Planobispora rosea, which is the producer of thiazolylpeptide GE2270. Among the mutants resistant to each single antibiotic, higher producers occurred more frequently (60%) among Gen^r than in Rif^r (10%) and Str^r (24%) populations. Two Gen^r mutants showed up to 1.5-fold improvement in GE2270 production while single resistant mutants Str^r and Rif^r produced slightly more than the parental strains. The combination of Str^r and Rif^r in the same strain improved GE2270 yield up to 1.7-fold. Finally, a higher GE2270 producing strain (1.8-fold improvement with respect to the parental strain) was selected among those mutants with triple resistance to streptomycin, rifamycin and gentamycin. A hierarchical increase in aerial mycelium and spore formation was observed which paralleled GE2270 production improvement.     

Apoptosis and atrophy in rat slow skeletal muscles in chronic heart failure

Congestive heart failure is characterized by a skeletal musclemyopathy with muscle bulk loss. The mechanisms responsible for thesechanges are not clear at present. We have investigated the role ofapoptosis in the rat "slow" soleus muscle during the developmentof heart failure, which was induced by injection of monocrotaline (30 mg/kg). We looked at the time course of apoptosis by studying sixanimals at each of the following time points: 0, 17, 24, and 30 days.We found a decreased expression of the antiapoptotic protein Bcl-2,which was accompanied by a rise of proapoptotic caspase-3. Ubiquitinlevels did not change. DNA nick-end labeling showed an increased numberof apoptotic nuclei both in myofibers and interstitial cells when heartfailure occurred. At variance with previous observations in thefast-twitch tibialis anterior muscle in the same animals, in whichtumor necrosis factor- (TNF-) increased at the time thatapoptosis occurred, the magnitude of apoptosis is lower in soleusmuscle and there is no appearance of muscle atrophy. In soleus muscle,apoptosis is accompanied by activation of the caspase-3 system. Thereis no activation of the TNF-- and ubiquitin-dependent protein waste.In conclusion, slow muscles are less prone to develop apoptosis thanfast muscles. Muscle atrophy appears earlier in these latter ones.

     

Hypoxia inhibits myogenic differentiation through accelerated MyoD degradation

Cells undergo a variety of biological responses when placed in hypoxic conditions, including alterations in metabolic state and growth rate. Here we investigated the effect of hypoxia on the ability of myogenic cells to differentiate in culture. Exposure of myoblasts to hypoxia strongly inhibited multinucleated myotube formation and the expression of differentiation markers. We showed that hypoxia reversibly inhibited MyoD, Myf5, and myogenin expression. One key step in skeletal muscle differentiation involves the up-regulation of the cell cycle-dependent kinase inhibitors p21 and p27 as well as the product of the retinoblastoma gene (pRb). Myoblasts cultured under hypoxic conditions in differentiation medium failed to up-regulate both p21 and pRb despite the G1 cell cycle arrest, as evidenced by p27 accumulation and pRb hypophosphorylation. Hypoxia-dependent inhibition of differentiation was associated with MyoD degradation by the ubiquitin-proteasome pathway. MyoD overexpression in C2C12 myoblasts overrode the differentiation block imposed by hypoxic conditions. Thus, hypoxia by inducing MyoD degradation blocked accumulation of early myogenic differentiation markers such as myogenin and p21 and pRb, preventing both permanent cell cycle withdraw and terminal differentiation. Our study revealed a novel anti-differentiation effect exerted by hypoxia in myogenic cells and identified MyoD degradation as a relevant target of hypoxia.     

Adenosine triphosphate concentration and beta-D-glucuronidase activity as indicators of sea bass semen quality

The most common parameters used to evaluate sperm quality are motility rate and duration and fertilization ability. In this study, chemical and biochemical parameters of sea bass (Dicentrarchus labrax) sperm were investigated to find an alternative method for evaluating sperm fertilization ability before and after cryopreservation. The biochemical and chemical analyses were performed with fresh and frozen-thawed sperm and seminal plasma. To cryopreserve sperm, 250-microl straws were used. Fertilization ability was evaluated by inseminating eggs (obtained from hormonally stimulated females) with fresh and cryopreserved sperm. The results revealed a linear relationship (P < 0.05) between semen fertilization capacity and some seminal plasma (beta-D-glucuronidase activity, potassium concentration) and sperm (ATP concentration, aspartate aminotransferase activity) parameters. Variations in semen fertilization rate could be best described by two multiple regression models: one including the sperm parameters and another including the seminal plasma parameters. For practical application, the use of simple regression models is of value. Fertilization rate in both fresh and cryopreserved sperm was reliably predicted by determining the ATP concentration or the beta-D-glucuronidase activity or both.     

Phylogeographic analysis of haplogroup E3b (E-M215) y chromosomes reveals multiple migratory events within and out of Africa

We explored the phylogeography of human Y-chromosomal haplogroup E3b by analyzing 3401 individuals from five continents. Our data refine the phylogeny of the entire haplogroup, which appears as a collection of lineages with very different evolutionary histories, and reveal signatures of several distinct processes of migrations and/or recurrent gene flow that occurred in Africa and western Eurasia over the past 25000 years. In Europe, the overall frequency pattern of haplogroup E-M78 does not support the hypothesis of a uniform spread of people from a single parental Near Eastern population. The distribution of E-M81 chromosomes in Africa closely matches the present area of distribution of Berber-speaking populations on the continent, suggesting a close haplogroup-ethnic group parallelism. E-M34 chromosomes were more likely introduced in Ethiopia from the Near East. In conclusion, the present study shows that earlier work based on fewer Y-chromosome markers led to rather simple historical interpretations and highlights the fact that many population-genetic analyses are not robust to a poorly resolved phylogeny.