Identification of a unicellular,non-pigmented alga that mediates growth inhibition in anuran tadpoles: a new species of the genus Prototheca (Chlorophyceae: Chlorococcales)

A non-pigmented, unicellular alga isolated from the faeces of British anuran tadpoles and which is associated with growth inhibition in these tadpoles, was described and identified using cytological, ultrastructural, nutrient assimilation and immunological studies. The alga possessed all the distinctive morphological features of the genus Prototheca, it grew weakly on Prototheca Isolation Medium (PIM), it required thiamine for continued growth and replication, and it could assimilate the five major substrates used to speciate the protothecans. All of these characteristics, together with previous nucleic acid hybridisation studies, indicated that the microorganism belonged to the genus Prototheca. There are currently five species recognised as valid (Pore, 1985 & 1986): Prototheca zopfii Kruger, 1884, P. wickerhamii Tubaki & Soneda, 1959, P. moriformis Kruger, 1884, P. stagnora Cooke, 1968 and P. ulmea Pore, 1986.The immunology showed that the new species was related to two of the protothecans, but overall it showed that the alga was antigenically distinct from the other protothecans tested in the immunoassay. This, together with its inability to grow strongly on PIM, its ability to assimilate a wide rage of carbon substrates and its ability to mediate growth inhibition in anuran tadpoles, indicated a new species of Prototheca. We therefore propose the name Prototheca richardsi sp. n.     

Déficit androgénique lié à l’âge. Que faut-il attendre de l’androgénothérapie?

With the exception of disease or drug-induced changes in Leydig cell function, aging is accompanied by specific changes of androgen status in healthy men. The level of testosterone production decreases in contrast with the rise in plasma protein testosterone binding capacity. Free testosterone, considered to be the biologically active fraction, decreases, leading to tissue androgen deficiency. The resulting clinical picture mimics hypogonadism, including physical and psychological asthenia, decreased libido and sexual behaviour, increased fat mass and decreased lean mass, gynaecomastia, osteoporosis and pro-atherogenic metabolic changes. The cut-off value for plasma testosterone below which androgen deficiency can be considered to be responsible for clinical signs is a key point which determines the therapeutic approach. In the absence of clearly validated data in healthy aging males, this cut-off value has been consensually defined as the mean plasma testosterone levels of men between 30 and 50 years of age minus two standard deviations, corresponding to the zone of hypogonadism in adult males. The association of clinical signs compatible with hypogonadism and reduced total (or preferably bioavailable) plasma testosterone level justifies initiation of hormone replacement therapy after excluding any contraindications (especially prostatic). The aim of this treatment is to reverse the consequences of age-related hypogonadism. Some benefits of this treatment have been clearly demonstrated, such as a decrease of fat mass, and an increase of lean mass and muscle strength. Similarly, bone mineral density increases, particularly in men with the lowest pretreatment plasma testosterone levels. It must be stressed that these changes are observed in truly hypogonadal aging men, but not in aging men with normal plasma testosterone levels. Testosterone replacement therapy can promote the development of gynaecomastia, while dihydrotestosterone tends to reduce gynaecomastia. Finally, androgen replacement therapy appears to improve a hypogonadism-related decrease in libido or sexual behaviour, provided other associated non-endocrine factors have been previously treated. Androgen replacement therapy improves well-being, and physical and psychological asthenia in hypogonadal men. However, this treatment has not been demonstrated to be effective in healthy aging men. Although androgen replacement therapy does not have a negative impact on lipid parameters, its possible cardiovascular protective effects have not yet been demonstrated. In conclusion, androgen replacement therapy, respecting the contraindications, is beneficial in patients of all ages with clearly demonstrated hypogonadism, but has no efficacy on symptoms in other cases.     

Characterization of the amino acids involved in substrate specificity of methionine sulfoxide reductase A

Methionine sulfoxide reductases (Msrs) are ubiquitous enzymes that catalyze the thioredoxin-dependent reduction of methionine sulfoxide (MetSO) back to methionine. In vivo, Msrs are essential in protecting cells against oxidative damages on proteins and in the virulence of some bacteria. There exists two structurally unrelated classes of Msrs. MsrAs are stereo-specific toward the S epimer on the sulfur of the sulfoxide, whereas MsrBs are specific toward the R isomer. Both classes of Msrs display a similar catalytic mechanism of sulfoxide reduction by thiols via the sulfenic acid chemistry and a better affinity for protein-bound MetSO than for free MetSO. Recently, the role of the amino acids implicated in the catalysis of the reductase step of Neisseria meningitidis MsrA was determined. In the present study, the invariant amino acids potentially involved in substrate binding, i.e. Phe-52, Trp-53, Asp-129, His-186, Tyr-189, and Tyr-197, were substituted. The catalytic parameters under steady-state conditions and of the reductase step of the mutated MsrAs were determined and compared with those of the wild type. Altogether, the results support the presence of at least two binding subsites. The first one, whose contribution is major in the efficiency of the reductase step and in which the epsilon-methyl group of MetSO binds, is the hydrophobic pocket formed by Phe-52 and Trp-53, the position of the indole ring being stabilized by interactions with His-186 and Tyr-189. The second subsite composed of Asp-129 and Tyr-197 contributes to the binding of the main chain of the substrate but to a lesser extent.     

A Rhodococcus qsdA-encoded enzyme defines a novel class of large-spectrum quorum-quenching lactonases

A gene involved in N-acyl homoserine lactone (N-AHSL) degradation was identified by screening a genomic library of Rhodococcus erythropolis strain W2. This gene, named qsdA (for quorum-sensing signal degradation), encodes an N-AHSL lactonase unrelated to the two previously characterized N-AHSL-degrading enzymes, i.e., the lactonase AiiA and the amidohydrolase AiiD. QsdA is related to phosphotriesterases and constitutes the reference of a novel class of N-AHSL degradation enzymes. It confers the ability to inactivate N-AHSLs with an acyl chain ranging from C(6) to C(14), with or without substitution at carbon 3. Screening of a collection of 15 Rhodococcus strains and strains closely related to this genus clearly highlighted the relationship between the ability to degrade N-AHSLs and the presence of the qsdA gene in Rhodococcus. Bacteria harboring the qsdA gene interfere very efficiently with quorum-sensing-regulated functions, demonstrating that qsdA is a valuable tool for developing quorum-quenching procedures.     

ELLIPSE Study: A Phase 1 study evaluating the tolerance of bevacizumab nasal spray in the treatment of epistaxis in hereditary hemorrhagic telangiectasia

Background: Hereditary hemorrhagic telangiectasia (HHT) is a dominantly inherited genetic vascular disorder in which epistaxis is the most frequent manifestation, responsible for high morbidity. Management of this symptom has no standard, and local treatments are often aggressive. Their efficacy is variable and has not been proven. Anti-angiogenic drugs, such as bevacizumab, are a new treatment strategy. Its systemic administration in patients with HHT improves liver damage-related symptoms and epistaxis. To limit the systemic adverse effects of bevacizumab and to ease administration, a local administration seems suitable. Primary objective: To evaluate the tolerance of increasing doses of bevacizumab administered as a nasal spray in patients with HHT-related epistaxis. Secondary objectives were to study the bioavailability and efficacy of bevacizumab against epistaxis when given as a nasal spray. Methodology: Phase 1, randomized, double-blind, placebo-controlled, monocentric study performed sequentially (dose escalation) on 5 groups of 8 patients. Each group was made up of 6 verum and 2 placebos. Five increasing doses of bevacizumab nasal spray (25 mg/mL) were evaluated: 12.5, 25, 50, 75 and 100 mg. Results: A total of 40 patients were included between October 2011 and October 2012. Bevacizumab nasal spray was well tolerated in all patients and the drug was not detected in their serum. No dose limiting toxicity was observed. No efficacy was observed at any dose in this study. Conclusion: Based on these results, bevacizumab nasal spray is a safe treatment of epistaxis in HHT. However, a randomized Phase 2 study is needed to determine its efficacy. Trial Registration: ClinicalTrials.gov Identifier #{"type":"clinical-trial","attrs":{"text":"NCT01507480","term_id":"NCT01507480"}}NCT01507480     

Doing No Harm? Adverse Events in a Nation-Wide Cohort of Patients with Multidrug-Resistant Tuberculosis in Nigeria

Background

Adverse events (AEs) of second line anti-tuberculosis drugs (SLDs) are relatively well documented. However, the actual burden has rarely been described in detail in programmatic settings. We investigated the occurrence of these events in the national cohort of multidrug-resistant tuberculosis (MDR-TB) patients in Nigeria.

Method

This was a retrospective, observational cohort study, using pharmacovigilance data systematically collected at all MDR-TB treatment centers in Nigeria. Characteristics of AEs during the intensive phase treatment were documented, and risk factors for development of AEs were assessed.

Results

Four hundred and sixty patients were included in the analysis: 62% were male; median age was 33 years [Interquartile Range (IQR):28–42] and median weight was 51 kg (IQR: 45–59). Two hundred and three (44%) patients experienced AEs; four died of conditions associated with SLD AEs. Gastro-intestinal (n = 100), neurological (n = 75), ototoxic (n = 72) and psychiatric (n = 60) AEs were the most commonly reported, whereas ototoxic and psychiatric AEs were the most debilitating. Majority of AEs developed after 1–2 months of therapy, and resolved in less than a month after treatment. Some treatment centers were twice as likely to report AEs compared with others, highlighting significant inconsistencies in reporting at different treatment centers. Patients with a higher body weight had an increased risk of experiencing AEs. No differences were observed in risk of AEs between HIV-infected and uninfected patients. Similarly, age was not significantly associated with AEs.

Conclusion

Patients in the Nigerian MDR-TB cohort experienced a wide range of AEs, some of which were disabling and fatal. Early identification and prompt management as well as standardized reporting of AEs at all levels of healthcare, including the community is urgently needed. Safer regimens for drug-resistant TB with the shortest duration are advocated.     

Identification of human populations with a high incidence of cellular immunity against breast carcinoma

Summary Cell mediated immunity specifically directed against breast carcinoma, but not against osteogenic sarcoma or other carcinomas, was found to occur in the household contacts of patients with active breast carcinoma (primary and metastatic). Such immunity was not found in the normal population, nor in household contacts of patients with osteogenic sarcoma; it was also not found in household contacts of breast carcinoma patients who had been disease free for two or more years. Patients with breast carcinoma had cytotoxicity indexes (CI) comparable to the normal population, regardless of their clinical condition.     

Ontogeny of Toll-like receptor mediated cytokine responses of human blood mononuclear cells

Newborns and young infants suffer increased infectious morbidity and mortality as compared to older children and adults. Morbidity and mortality due to infection are highest during the first weeks of life, decreasing over several years. Furthermore, most vaccines are not administered around birth, but over the first few years of life. A more complete understanding of the ontogeny of the immune system over the first years of life is thus urgently needed. Here, we applied the most comprehensive analysis focused on the innate immune response following TLR stimulation over the first 2 years of life in the largest such longitudinal cohort studied to-date (35 subjects). We found that innate TLR responses (i) known to support Th17 adaptive immune responses (IL-23, IL-6) peaked around birth and declined over the following 2 years only to increase again by adulthood; (ii) potentially supporting antiviral defense (IFN-α) reached adult level function by 1 year of age; (iii) known to support Th1 type immunity (IL-12p70, IFN-γ) slowly rose from a low at birth but remained far below adult responses even at 2 years of age; (iv) inducing IL-10 production steadily declined from a high around birth to adult levels by 1 or 2 years of age, and; (v) leading to production of TNF-α or IL-1β varied by stimuli. Our data contradict the notion of a linear progression from an 'immature' neonatal to a 'mature' adult pattern, but instead indicate the existence of qualitative and quantitative age-specific changes in innate immune reactivity in response to TLR stimulation.     

From dormant to germinating spores of Streptomyces coelicolor A3(2): new perspectives from the crp null mutant

The complete understanding of the morphological differentiation of streptomycetes is an ambitious challenge as diverse sensors and pathways sensitive to various environmental stimuli control the process. Germination occupies a particular position in the life cycle as the good achievement of the process depends on events occurring both during the preceding sporulation and during germination per se. The cyclic AMP receptor protein (crp) null mutant of Streptomyces coelicolor, affected in both sporulation and germination, was therefore presented as a privileged candidate to highlight new proteins involved in the shift from dormant to germinating spores. Our multidisciplinary approach-combining in vivo data, the analysis of spores morphological properties, and a proteome study-has shown that Crp is a central regulatory protein of the life cycle in S. coelicolor; and has identified spores proteins with statistically significant increased or decreased expression that should be listed as priority targets for further investigations on proteins that trigger both ends of the life cycle.