Nutrient signalling in the regulation of human muscle protein synthesis

The mammalian target of rapamycin (mTOR) and AMP-activated protein kinase (AMPK) are important nutrient- and energy-sensing and signalling proteins in skeletal muscle. AMPK activation decreases muscle protein synthesis by inhibiting mTOR signalling to regulatory proteins associated with translation initiation and elongation. On the other hand, essential amino acids (leucine in particular) and insulin stimulate mTOR signalling and protein synthesis. We hypothesized that anabolic nutrients would be sensed by both AMPK and mTOR, resulting in an acute and potent stimulation of human skeletal muscle protein synthesis via enhanced translation initiation and elongation.
We measured muscle protein synthesis and mTOR-associated upstream and downstream signalling proteins in young male subjects ( n = 14) using stable isotopic and immunoblotting techniques. Following a first muscle biopsy, subjects in the 'Nutrition' group ingested a leucine-enriched essential amino acid–carbohydrate mixture (EAC). Subjects in the Control group did not consume nutrients. A second biopsy was obtained 1 h later. Ingestion of EAC significantly increased muscle protein synthesis, modestly reduced AMPK phosphorylation, and increased Akt/PKB (protein kinase B) and mTOR phosphorylation ( P < 0.05). mTOR signalling to its downstream effectors (S6 kinase 1 (S6K1) and 4E-binding protein 1 (4E-BP1) phosphorylation status) was also increased ( P < 0.05). In addition, eukaryotic elongation factor 2 (eEF2) phosphorylation was significantly reduced ( P < 0.05). Protein synthesis and cell signalling (phosphorylation status) was unchanged in the control group ( P > 0.05).
We conclude that anabolic nutrients alter the phosphorylation status of both AMPK- and mTOR-associated signalling proteins in human muscle, in association with an increase in protein synthesis not only via enhanced translation initiation but also through signalling promoting translation elongation.     

The effect of acriflavine on the complement sensitive and resistant strains of Escherichia coli and on complement resistant mutants

Complement sensitive and resistant smooth strains of Escherichia coli have been distinguished by their different reaction with acriflavine analysed spectrophotometrically. Resistant mutants of sensitive strains were obtained and found to react like wild type resistant strains.     

Methicillin-resistant Staphylococcus aureus: laboratory detection methods in use in the Republic of Ireland and Northern Ireland

There is no universally agreed laboratory protocol for the detection of methicillin-resistant Staphylococcus aureus (MRSA) and hence a variety of approaches are used. As part of an all-island survey of MRSA in the Republic of Ireland (the South) and Northern Ireland (the North), a questionnaire was circulated to 14 participating laboratories in the North and 49 in the South, to determine the methods used to isolate MRSA from clinical specimens, identify S. aureus and test for susceptibility to methicillin. Almost two-thirds (64%) of laboratories in the North but only 16% of laboratories in the South use enrichment culture. There is heavy reliance on commercial kits to confirm the identification of S. aureus in the South but all laboratories in the North use the staphylocoagulase test. More than 90% of all laboratories use a disc method for susceptibility testing and 71% of laboratories in the North supplement this with the E-test; however, a range of methicillin disk concentrations are in use. There is a need to review current laboratory methods used to detect MRSA, with follow-up audit on their implementation. Additional resources may be needed in some laboratories to comply with revised guidelines, and reference facilities are required to assess new commercially available techniques and to confirm the identification of unusual or difficult strains.     

An adjustable microplate platform

Summary An adjustable platform has been designed to facilitate the addition of biological assay components to a multiwell microplate. Nonmanifold additions of liquid components to microplate wells are made especially easy by using this device. The microplate platform can accommodate any of the common formats of disposable microplates. Moreover, it can be adjusted to varying angles allowing the investigator to view into all the wells as assay components are being added.     

The antigenicity of some synthetic poly-iminoacids: I. Antigenic properties of poly-L-proline

The antigenic properties of a group of synthetic poly-iminoacids have been tested in guinea-pigs and rabbits by active cutaneous anaphylaxis, delayed skin hypersensitivity reactions, passive cutaneous anaphylaxis, (PCA), tanned cell agglutination and agglutination-inhibition. The antigenicity of a linear homopolymer, poly-L-proline, has been demonstrated in guinea-pigs. This polymer exists in two forms differing only in their secondary structure, Form I having a right-handed helix and Form II a left-handed helix. That both forms are antigenic and yet non-cross-reacting emphasizes the importance of secondary structure in this system.Comparison of polyprolines of different molecular weights suggests the presence of more than one antigenic determinant; a polymer of an average molecular weight of 1500 was antigenically deficient compared with a polyproline of a molecular weight of 17,000.No cross-reactions were detected between anti-polyproline or anti-polyproline-glycine and collagen or its derivatives.The possible structure of the antigenic determinants involved is discussed.     

Is the smoking decision an 'informed choice'? Effect of smoking risk factors on smoking beliefs

The argument that people freely choose to smoke assumes that individuals at the point of initiation of smoking (often in adolescence) hold accurate beliefs about smoking. Smoking beliefs and the presence of known smoking risk factors were assessed in interviews with a sample of 895 urban young people. The respondents greatly overestimated the prevalence of adult and peer smoking, negative attitudes of their peers were greatly underestimated, a large proportion believed that they would be less likely than other people to contract a smoking-related illness if they became smokers, and there was a general lack of understanding of the adverse consequences experienced upon smoking cessation. These misperceptions were more common among youngsters who were smokers, who intended to smoke, or who had friends or family members who smoked. Because misinformation among young people is widespread and those at greatest risk for smoking are the most misinformed, the tobacco industry's argument that the decision to smoke reflects an "informed choice" is without merit.     

Aneurysmal subarachnoid hemorrhage during pregnancy: a comprehensive and systematic review of the literature

Neurosurgical Review - Aneurysmal subarachnoid hemorrhage (aSAH) is an emergent condition requiring rapid intervention and prolonged monitoring. There are few recommendations regarding the...     

Role of Staphylococcus aureus cell wall antigens in the stimulation of delayed hypersensitivity after staphylococcal infection.

In Staphylococcus aureus-infected mice, prior treatment with cyclophosphamide enhanced delayed hypersensitivity to cell walls and peptidoglycan. S. aureus did not cross react with S. epidermidis or S. saprophyticus.     

Otolaryngology Consultation for Peritonsillar Abscess in the Pediatric Population

Objective To assess clinical outcomes of children seen in consultation for peritonsillar abscess treated without the routine use of computed tomography or needle aspiration. Study Design Retrospective review of patients evaluated in the emergency department for possible peritonsillar abscess. Patient outcomes are reviewed with a statistical analysis of children grouped according to age. Methods A series of 102 patients, ages 8 months to 19 years, who were evaluated by the emergency department with otolaryngology consultation for possible peritonsillar abscess. All patients were admitted and given intravenous fluid replacement, antibiotics, and analgesia. Patients who responded to 24 hours of medical treatment were discharged, whereas patients who did not respond underwent elective tonsillectomy. Main Outcome Measure Outcome of patients evaluated for peritonsillar abscess treated without immediate surgery, needle aspiration, or computed tomography. Outcomes are correlated with age and clinical findings. Results Fifty‐two patients were discharged after initial medical therapy. Fifty patients underwent elective tonsillectomy; 40 of these patients were found to have abscesses at the time of surgery. When analyzed according to age, patients ages 8 months to 6 years were more likely to respond to medical treatment than children ages 7 to 12 and 12 to 19 (P = .023). Significant differences in the mean age of children requiring surgery (11.0 y) compared with those who responded to medical treatment (7.9 y) were observed (P = .003). Younger children who underwent tonsillectomy had a lower incidence of surgically confirmed abscess. Conclusions A significant number of children presenting with odynophagia, malaise, pharyngotonsillar bulge, and decreased oral intake respond to medical therapy without radiological evaluation or surgical intervention. Additionally, younger children (1–6 y) are more likely to respond to medical treatment than older children. Pertinent clinical data, as well as advantages and disadvantages of this approach, are discussed.