Comet assay on gill cells and hemocytes from the blue mussel Mytilus edulis

Gill cells and hemocytes from the blue mussel Mytilus edulis were examined for DNA damage using the comet assay after laboratory exposure in vitro and in vivo to methyl methansulfonate (MMS). Hydrogen peroxide and UV radiation were used as positive control. Comet assay was also carried out on hemocytes from blue mussels sampled at polluted and unpolluted coastal areas. After 60 min in vitro exposure of gill cells to MMS, the highest response, a tail moment of 6.70+/-4.25, was obtained at 1.0mg/L. At higher doses the response decreased. After 2 days in vivo exposure a dose response was seen at concentrations between 1.0 and 33.0mg/L MMS for both gill cells and hemocytes. However, after 4 days in vivo exposure using the same concentrations of MMS, a maximum effect was seen at a 10 times lower concentration of 3.3mg/L. At the higher doses, the effect decreased. Hemocytes from blue mussels sampled at four polluted sites in K?ge Bay had a great variation in tail moments with the highest value of 5.38+/-4.39. The average of all samples from K?ge Bay had tail moments of 2.75+/-1.00(n=19), which was significantly higher (P<0.05) than the average, 1.72+/-1.16(n=10), of samples from unpolluted coastal waters.     

Insulin induces cobalt uptake in a subpopulation of rat cultured primary sensory neurons

Previous findings show that both the vanilloid receptor 1 and the insulin receptor are expressed on small primary sensory neurons. As insulin evokes activity in second messengers which could induce opening of the vanilloid receptor 1, we examined, by using the cobalt-uptake technique, whether or not insulin can activate cultured rat primary sensory neurons through activating the vanilloid receptor 1. Capsaicin (50, 100 and 500 nm) induced concentration-dependent labelling in primary sensory neurons. Preincubation of cells in insulin (10 micromoles) for 10 min followed by a 2-min wash did not produce significant change in the capsaicin-induced labelling. Coapplication of insulin (10 micromoles) with capsaicin, however, potentiated the 50 and 100 nm capsaicin-evoked staining. Insulin itself also produced cobalt labelling in a concentration-dependent manner. The size-frequency distributions of neurons showing capsaicin- or insulin-induced cobalt accumulation were similar. The insulin-induced cobalt labelling was significantly reduced by the tyrosine kinase inhibitor, tyrphostin AG1024, the vanilloid receptor 1 antagonists, ruthenium red and capsazepine, the protein kinase inhibitor, staurosporine and the phospholipase C inhibitor neomycin. Double immunostaining of cultured primary sensory neurons and sections from dorsal root ganglia revealed that about one-third of the cells coexpress the insulin receptor and vanilloid receptor 1. These findings suggest that insulin activates a subpopulation of primary sensory neurons, probably through phosphorylation- and/or phosphatidylinositol(4,5)biphosphate hydrolysis-evoked activation of the vanilloid receptor 1. Although the insulin-induced activation of vanilloid receptor 1 seems to be a short-lived effect in vitro, in vivo it might play a role in the development of burning pain sensation in hyperinsulinism.     

Medical Student Competence in Eliciting a History for “Chronic Fatigue”

Purpose: We report an observational study of medical students abilities in taking a complex history for which sleep disorders is one of several possible conditions. Methods: Students are observed taking a focused history from a simulated patient whose chief complaint is I am tired. I cannot get anything done. Nine groups of students (n = 360) completing the internal medicine core-clerkship were evaluated by one of three examiners. Students received full, partial, or no credit for each item on a uniform behavioral checklist, which included prompts for common medical and psychiatric disorders associated with chronic fatigue. Results: Observed means were lowest for items pertaining to sleep behaviors and head trauma. Fewer than half of the students inquired about whether or not the person had difficulty falling asleep at night, family history of sleep apnea, and frequency and length of naps. In contrast, the majority of students inquired about heart disease, metabolic disorders, the use of illicit drugs, alcohol consumption, and the taking of medications. Examiners accounted for a significant source of variance in scores; yet the station discriminated among top and bottom students as measured by the Objective Structured Clinical Examination (OSCE) overall. No statistically significant differences were observed on the basis of clerkship site, primary care versus traditional-track students, time of year, or gender. Conclusion: A majority of students do not adequately cover issues relevant to sleep in contrast to other associated disorders when taking a focused history for chronic fatigue.     

Activation of B cell apoptotic pathways in the course of Francisella tularensis infection

Francisella tularensis is a facultative intracellular, gram-negative bacterium that induces apoptosis in macrophages and B cells. Here we show apoptotic pathways that are activated in the Ramos human B cell line in the course of F. tularensis infection. Live bacteria F. tularensis FSC200 activate caspases 8, 9 and 3, as well as Bid; release cytochrome c and apoptosis-inducing factor from mitochondria; and induce depolarization of mitochondrial membrane potential in the Ramos cell line, thus leading these cells to apoptosis. Unlike live bacteria, killed F. tularensis FSC200 bacteria activated only caspase 3, and did not cause apoptosis of Ramos cells as measured by annexin V. Killed bacteria also caused accumulation of anti-apoptotic protein Bclx_L in mitochondrial membranes. Thus, live F. tularensis activates both caspase pathways (receptor-mediated and intrinsic) as well as caspase-independent mitochondrial death.     

Young adolescents' independent mobility,related factors and association with transport to school. A cross-sectional study

Background  

Children's independent mobility differs between groups of adolescents, but knowledge is lacking on how mobility-limiting factors interact. This study explores the association between factors that can affect young adolescents' mobility, searching for typical patterns within a geographical area where mobility is both relatively high and promoted (in this case Stockholm County, Sweden). An additional question is how clusters of limiting factors and demographic attributes relate to active commuting to school.     

The application of Item Response Theory on a teaching strategy profile questionnaire

Background  

In medical education research, various questionnaires are often used to study possible relationships between strategies and approaches to teaching and learning and the outcome of these. However, judging the applicability of such questionnaires or the interpretation of the results is not trivial.     

Nebivolol and metoprolol for treating migraine: an advance on beta-blocker treatment?

OBJECTIVE: To evaluate the efficacy of oral treatment with nebivolol and metoprolol in the prophylaxis of migraine attacks. BACKGROUND: Beta-blockers such as propranolol and metoprolol are known to be effective in preventing migraine attacks. Following earlier observations of successful use of nebivolol in a few hypertensive patients with concomitant migraine, we conducted a prospective study to ascertain whether nebivolol would be effective and better tolerated, in a methodologically strict, randomized and double-blind setting. DESIGN AND METHODS: Randomized, double-blind study in 30 patients with confirmed migraine diagnosis, a minimum 1-year history, onset prior to 50 years of age, written records of attacks for the previous 3 months, and minimum 2 attacks per month. Primary endpoint was frequency of attacks (prevention of migraine attacks) in the final 4 weeks of a 14-week treatment on full dose of metoprolol and nebivolol. Secondary endpoints were time to therapeutic effect, duration of attacks, intensity of headache, consumption of analgesics, evaluation of accompanying symptoms, migraine disability assessment, clinical global impression, quality of life, and responder rates. The statistical analysis was prospectively planned and conducted for all randomized patients. RESULTS: Both metoprolol and nebivolol where similarly effective regarding the main endpoint (prevention of migraine attacks) as well as the secondary ones, and both had a fast onset of action, typically within 4 weeks from starting therapy, with responder rates increasing relatively little over time after the first 4 weeks. Use of acute pain medication decreased on both drugs, as well as accompanying symptoms. Both patients' and physicians' evaluations of disability and disease status were similarly favorable to the 2 treatments. Regarding safety, nebivolol was considerably better tolerated than metoprolol in terms of all reported events, treatment-related events, and event severity. CONCLUSIONS: Our results suggest that nebivolol is as effective as metoprolol in the prophylaxis of migraine attacks, with the advantages of being better tolerated and not requiring up-titration to achieve therapeutic levels. Further and larger trials should be conducted on nebivolol in the prevention of migraine attacks as it may provide an improvement in current migraine prophylaxis with beta-blockers.     

The visual impact of fractionated stereotactic conformal radiotherapy on seven eyes with optic nerve sheath meningiomas.

BACKGROUND: Treatment of primary optic nerve sheath meningiomas (ONSMs) remains controversial. Although recent studies have suggested a favorable outcome of radiotherapy, controlled data on the efficacy of fractionated stereotactic conformal radiotherapy (SCRT) in primary ONSMs are still lacking. METHODS: Seven eyes treated with SCRT (total dose: 54 Gy) were compared with six eyes that were not treated because of patient or physician preference. The indication for intervention was deterioration of visual function with or without imaging evidence of tumor progression. Patients with secondary ONSMs and those with neurofibromatosis type 2 were excluded. The mean follow-up period was 57 months for the treated eyes and 61 months for the untreated eyes. RESULTS: Among the seven treated eyes, visual acuity improved in six, five of which sustained improvement of three or more Snellen lines. One eye deteriorated by two lines. Visual field improved in four eyes, remained stable in two, and deteriorated in one. Four untreated eyes showed worsening of visual acuity and two remained stable. Visual field deteriorated in three eyes and was stable in three. None of the untreated eyes experienced improvement in visual acuity or visual field. No complications of treatment were documented. CONCLUSIONS: In agreement with previous reports, these results indicate that SCRT is superior to observation in its impact on visual function in eyes with primary ONSMs.     

Effects of the Ca2+ sensitizers EMD 57033 and CGP 48506 on myocardial contractility and Ca2+ transients in human ventricular and atrial myocardium

Zusammenfassung Ca²⁺-Sensitizer, wie z.B. EMD 57033 (EMD) und CGP 48506 (CGP) erhöhen die Kontraktionskraft ohne dabei den intrazellulären Ca²⁺-Transienten zu erhöhen und sind somit möglicherweise für die Behandlung der menschlichen Herzinsuffizienz von Bedeutung. Es ist jedoch unklar, ob sich Ca²⁺-Sensitizer in ihrem pharmakokinetischen Wirkprinzip am menschlichen Myokard unterscheiden. Daher wurde der Einfluss von EMD und CGP auf die Kontraktionskraft und den intrazellulären Ca²⁺-Transienten (Fura 2) an linksventrikulären Papillarmuskelstreifen (PAP) von menschlichem insuffizientem Myokard sowie in rechtsatrialen Trabekeln (RA) von Patienten untersucht, die sich einer aortokoronaren Bypass-Operation unterziehen mussten. In PAP wurde die Kraft effizienter und stärker nach Applikation von EMD (EC₅₀ EMD: 4,7ǃ,0 7mol/l, max. PIE EMD: +12,0DŽ,0 mN/mm²) erhöht als nach CGP (EC₅₀: 16,9lj,6 7mol/l, max. PIE: +6,4DŽ,8 mN/mm²). Ähnliche Ergebnisse wurden an RA erhalten. Carbachol (100 7mol/l) hatte keinen Einfluss auf die positiv inotrope Wirkung von EMD und CGP. Beide Ca²⁺-Sensitizer erhöhten signifikant die Relaxationszeit und die diastolischen Spannung. EMD und CGP veränderten den intrazellulären Ca²⁺-Transienten nicht. Schlussfolgerung Die Ca²⁺-Sensitizer EMD und CGP erhöhen cAMP- und Ca²⁺-unabhängig die Kontraktionskraft am menschlichen Myokard. Da sie die Relaxation beeinträchtigen, ist ihr therapeutischer Nutzen für die Herzinsuffizienz begrenzt. Summary Ca²⁺ sensitizers like EMD 57033 (EMD) and CGP 48506 (CGP) may be advantageous for the treatment of human heart failure, as they increase force of contraction without increasing the intracellular Ca²⁺ transients or energy consumption. However, whether or not Ca²⁺ sensitizers differ in their mode of action in human myocardium is not fully understood. The present study investigates the influence of EMD and CGP on force of contraction (FOC) and the intracellular Ca²⁺ transient (fura-2 ratio method) in left ventricular papillary muscle strips from left ventricular failing human myocardium (DCM, n=28) as well as in right atrial trabeculae (RA, n=21) obtained from patients undergoing cardiac bypass surgery. In isolated trabeculae of DCM, FOC was more efficacious and potently increased after application of EMD (EC₅₀ EMD: 4.7ǃ.0 7mol/l, max. PIE EMD: +12.0DŽ.0 mN/mm²) than CGP (EC₅₀: 16.9lj.6 7mol/l, max. PIE: +6.4DŽ.8 mN/mm²). Similar results were obtained in RA. Application of carbachol (100 7mol/l) had no effect on the positive inotropic effect of EMD or CGP. Both Ca²⁺ sensitizers significantly increased time to half peak relaxation as well as diastolic tension in DCM. EMD (10 7mol/l) and CGP (30 7mol/l) did not affect the Ca²⁺ transients in RA. The Ca²⁺ sensitizers EMD and CGP increase cAMP and Ca²⁺ independently from the force of contraction in the human myocardium. However, their therapeutic use in human heart failure may be limited as they impair relaxation.     

Does continuous flow apheresis influence viability in allogeneic hematopoietic stem cell harvest?

One of the important clinical variables determining the success of hematopoietic stem cell transplantation is the number of viable CD34+ stem cells transfused to the patient. G-CSF mobilized peripheral blood stem cells from 17 healthy donors were collected by continuous flow apheresis. The median (range) proportions of early apoptotic (Annexin V-FITC(pos)/7-AAD(neg)) and viable (Annexin V-FITC(neg)/7-AAD(neg)) CD45(dim)CD34+ stem cells were 1.5 (0.9-3.7)% and 97.7 (82.8-100)% in the peripheral blood before apheresis and 2.6 (0.8-7.9)% and 97.3 (91.9-99)% in the apheresis products, respectively. Despite an increase in the number of apoptotic cells among all cell compartments, this was statistically significant only in CD34+ cells and granulocytes. The majority of the cells still retained their viability.