Influenza H2 haemagglutinin activates B cells via a MyD88-dependent pathway

Influenza viruses are serious respiratory pathogens, responsible for half a million deaths each year. The viral surface haemagglutinin (HA) protein has been shown to be an important determinant of viral pathogenicity. HA is the virion attachment and fusion protein, and the major target for neutralizing antibodies; however, it is also involved in triggering innate responses that may have an important impact on the disease course. We have examined the role of the toll-like receptor (TLR) family in innate responses to influenza virus and influenza HA. TLR7 has recently been found to mediate recognition of influenza RNA. Here, we show for the first time that influenza HA of the H2 subtype induces innate responses in murine B lymphocytes via a MyD88-dependent pathway distinct from that involved in sensing viral RNA. We also show that inactivated influenza virus induces activation of human B cells. Our findings suggest that the molecule mediating these responses may be a novel member of the TLR family.     

Fine-tuning of cross-bridge kinetics in cardiac muscle of rat and mouse by myosin light chain isoforms

Cross-bridge kinetics underlying stretch-induced force transients was studied in cardiac muscle strips with different myosin heavy chain (MHC) and myosin light chain (MLC) isoforms. The force transients were induced by stepwise stretches of maximally Ca²⁺-activated skinned muscle strips. The MHC and MLC isoforms were analyzed by electrophoreses after the mechanical experiments. Muscle strips of euthyroid rats and mice exclusively containing α-MHC were used. In addition, muscle strips of hyper- and hypothyroid rats containing different combinations of MHC and MLC isoforms were used. The thyroid hormone is known to alter the expression of MHC but not of MLC isoforms. In muscle strips containing exclusively α-MHC, atrial MLC isoforms (all atria of rats and mice) were associated with about 30% faster kinetics than ventricular MLC isoforms (ventricles of hyperthyroid rats and some muscle strips of ventricles of euthyroid rats and mice). On the other hand, in muscle strips containing exclusively ventricular MLC isoforms, α-MHC (ventricles of hyperthyroid rats) was associated with about 2.6 times faster kinetics than β-MHC (ventricles of hypothyroid rats). We conclude that the MLC isoforms fine-tune cross-bridge kinetics, which underlies stretch-induced force transients, whereas the MHC isoforms mainly determine this kinetics. The effect of MLC isoforms on the cross-bridge kinetics may partially contribute to the faster twitch contraction in atria than in ventricles. Furthermore, it may play a role in various cardiomyopathies where atrial MLC isoforms are partially expressed in ventricles or ventricular MLC isoforms are partially expressed in atria.     

Plagiarism detection and prevention: a primer for researchers

Plagiarism is an ethical misconduct affecting the quality, readability, and trustworthiness of scholarly publications. Improving researcher awareness of plagiarism of words, ideas, and graphics is essential for avoiding unacceptable writing practices. Global editorial associations have publicized their statements on strategies to clean literature from redundant, stolen, and misleading information. Consulting related documents is advisable for upgrading author instructions and warning plagiarists of academic and other consequences of the unethical conduct. A lack of creative thinking and poor academic English skills are believed to compound most instances of redundant and “copy-and-paste” writing. Plagiarism detection software largely relies on reporting text similarities. However, manual checks are required to reveal inappropriate referencing, copyright violations, and substandard English writing.Medical researchers and authors may improve their writing skills and avoid the same errors by consulting the list of retractions due to plagiarism which are tracked on the PubMed platform and discussed on the Retraction Watch blog.     

Role of colonoscopy in the diagnostic work-up of bowel endometriosis

AIM:To evaluate the accuracy of colonoscopy for the prediction of intestinal involvement in deep pelvic endometriosis.METHODS:This prospective observational study was performed between September 2011 and July 2014.Only women with both a clinical and imaging diagnosis of deep pelvic endometriosis were included.The study was approved by the local ethics committee and written informed consent was obtained in all cases.Both colonoscopy and laparoscopy were performed by expert surgeons with a high level of expertise with these techniques.Laparoscopy was performed within4 wk of colonoscopic examination.All hypothetical colonoscopy findings(eccentric wall thickening with or without surface nodularities and polypoid lesions with or without surface nodularities of endometriosis)were compared with laparoscopic and histological findings.We calculated the sensitivity,specificity,positive predictive value and negative predictive value for the presence of colonoscopic findings of intestinal endometriosis.RESULTS:A total of 174 consecutive women aged between 21-42 years with a diagnosis of deep pelvic endometriosis who underwent colonoscopy andsurgical intervention were included in our analysis.In 76 of the women(43.6%),intestinal endometrial implants were found at surgery and histopathological examination.Specifically,38 of the 76 lesions(50%)were characterized by the presence of serosal bowel nodules;28 of the 76 lesions(36.8%)reached the muscularis layer;8 of the 76 lesions(10.5%)reached the submucosa;and 2 of the 76 lesions(2.6%)reached the mucosa.Colonoscopic findings suggestive of intestinal endometriosis were detected in 7 of the174(4%)examinations.Colonoscopy failed to diagnose intestinal endometriosis in 70 of the 76 women(92.1%).A colonoscopic diagnosis of endometriosis was obtained in all cases of mucosal involvement,in 3of 8 cases(37.5%)of submucosal involvement,in no cases of muscularis layer involvement and in 1 of 38cases(2.6%)of serosa involvement.The sensitivity,specificity,positive predictive and negative predictive values of colonoscopy for the diagnosis of intestinal endometriosis were 7%,98%,85%and 58%,respectively.CONCLUSION:Being an invasive procedure,colonoscopy should not be routinely performed in the diagnostic work-up of bowel endometriosis.     

How can one platelet injection after tendon injury lead to a stronger tendon after 4 weeks? Interplay between early regeneration and mechanical stimulation

BACKGROUND: Mechanical stimulation improves the repair of ruptured tendons. Injection of a platelet concentrate (platelet-rich plasma, PRP) can also improve repair in several animal models. In a rat Achilles tendon transection model, 1 postoperative injection resulted in increased strength after 4 weeks. Considering the short half-lives of factors released by platelets, this very late effect calls for an explanation. METHODS: We studied the effects of platelets on Achilles tendon regenerates in rats 3, 5 and 14 days after transection. The tendons were either unloaded by Botulinum toxin A (Botox) injections into the calf muscles, or mechanically stimulated in activity cages. No Botox injections and ordinary cages, respectively, served as controls. Repair was evaluated by tensile testing. RESULTS: At 14 days, unloading (with Botox) abolished any effect of the platelets and reduced the mechanical properties of the repair tissue to less than half of normal. Thus, some mechanical stimulation is a prerequisite for the effect of platelets at 14 days. Without Botox, both activity and platelets increased repair independently of each other. However, at 3 and 5 days, platelets improved the mechanical properties in Botox-treated rats. INTERPRETATION: Platelets influence only the early phases of regeneration, but this allows mechanical stimulation to start driving neo-tendon development at an earlier time point, which kept it constantly ahead of the controls.     

Audio computer assisted self interview and face to face interview modes in assessing response bias among STD clinic patients

BACKGROUND: Audio computer assisted self interview (ACASI) may minimise social desirability bias in the ascertainment of sensitive behaviours. The aim of this study was to describe the difference in reporting risk behaviour in ACASI compared to a face to face interview (FFI) among public sexually transmitted diseases (STD) clinic attendees. STUDY DESIGN: Randomly selected patients attending a public STD clinic in Baltimore, Maryland, sequentially took an ACASI formatted risk behaviour assessment followed by an FFI conducted by a single clinician, with both interview modalities surveying sexual and drug use behaviours. Binary responses were compared using the sign test, and categorical responses were compared using the Wilcoxon signed rank test to account for repeated measures. RESULTS: 671 (52% men, mean age 30 years, 95% African American) of 795 clinic attendees screened consented to participate. Subjects affirmed sensitive sexual behaviours such as same sex contact (p = 0.012), receptive rectal sexual exposure (p < 0.001), orogenital contact (p < 0.001), and a greater number of sex partners in the past month (p < 0.001) more frequently with ACASI than with an FFI. However, there were no differences in participant responses to questions on use of illicit drugs or needle sharing. CONCLUSIONS: Among STD clinic patients, reporting of sensitive sexual risk behaviours to clinicians was much more susceptible to social desirability bias than was reporting of illegal drug use behaviours. In STD clinics where screening of sexual risk is an essential component of STD prevention, the use of ACASI may be a more reliable assessment method than traditional FFI.     

Assessing the antifungal activity and toxicity profile of amphotericin B lipid complex (ABLC; Abelcet) in combination with caspofungin in experimental systemic aspergillosis

The purpose of this study was to assess the antifungal activity and renal and hepatic toxicity of amphotericin B lipid complex (ABLC; Abelcet) following co-administration of Caspofungin to rats infected with Aspergillus fumigatus. Aspergillus fumigatus inoculum (1.3-2.3 x 10(7) colony forming units [CFU]) was injected via the jugular vein; 48 h later male albino Sprague-Dawley rats (350-400 g) were administered either a single intravenous (i.v.) dose of Fungizone(R) (1 mg AmpB/kg), ABLC (1 or 5 mg AmpB/kg), or an equivalent volume of normal saline (NS) (vehicle control) once daily for 4 days. Rats were further randomized into groups to receive 3 mg/kg Caspofungin or physiologic saline i.v. once daily for 4 days. To assess antifungal activity, brain, lung, heart, liver, spleen, and kidney sections were homogenized with NS (2 mL; 1 g of each tissue/mL) and a 0.1-mL aliquot was spread plated onto a Sabouraud dextrose agar plate. The plates were incubated for 48 h at 37 degrees C, at which time the numbers of CFU were determined and corrected for tissue weight. To assess renal and hepatic toxicity, serum creatinine and aspartate aminotransferase levels were determined. Fungizone and ABLC at a dosing regimen of 1 mg/kg i.v. once daily for four consecutive days and Caspofungin at a dosing regimen of 3 mg/kg i.v. once daily for four consecutive days had similar effectiveness in decreasing the total number of Aspergillus fumigatus CFUs found in all organs analyzed compared to non-treated controls. A combination of ABLC (1 mg/kg i.v. x 4 days) and Caspofungin (3 mg/kg i.v. x 4 days) significantly decreased the total number of Aspergillus fumigatus CFUs found in all organs analyzed compared to Caspofungin alone and non-treated controls. ABLC at a dosing regiment of 5 mg/kg i.v. once daily for four consecutive days was more effective in decreasing the total number of Aspergillus fumigatus CFUs found in all organs analyzed compared to Fungizone or ABLC alone at 1 mg/kg and Caspofungin alone at 3 mg/kg. However, a combination of ABLC (5 mg/kg i.v. x 4 days) and Caspofungin (3 mg/kg i.v. x 4 days) was not more effective than ABLC at 5 mg/kg or the combination of ABLC at 1 mg/kg and Caspofungin 3 mg/kg in reducing the total number of Aspergillus fumigatus CFUs compared to controls. Except for non-treated infected control rats, none of the treatment groups tested displayed a greater than 50% increase in serum creatinine concentrations from baseline. In addition, only ABLC at a dosing regimen of 1 mg/kg i.v. once daily for four consecutive days displayed a greater than 50% increase in AST concentration from baseline. Taken together, these findings suggest that ABLC at 5 mg/kg once daily x 4 days appears to be the best therapeutic choice in this animal model.     

Modular arrangement of viral cis-acting RNA domains in a tombusvirus satellite RNA

Satellite (sat) RNAs are parasitic sub-viral RNA replicons found associated with certain positive-strand RNA viruses. Typical sat RNAs, such as those associated with members of the genus Tombusvirus, share little or no sequence identity with their helper virus genomes. Here, we have investigated a tombusvirus sat RNA and determined that it contains two functionally-relevant higher-order RNA domains, a T-shaped domain and a downstream domain, that are similar to elements shown previously to be present in the 5' untranslated regions (UTRs) of tombusvirus genomes. Although the two sat RNA domains showed only limited sequence identity with their viral counterparts, they were able to adopt comparably-folded RNA secondary structures. Interestingly, the relative spacing between the domains in the viral and satellite contexts was notably different. In the viral 5' UTR, the two domains are adjacent and separated by a small hairpin, however, in the sat RNA they are separated by a 137-nt long segment. Despite this distal modular arrangement, the two domains were found to be united spatially in the sat RNA through the formation of an RNA-RNA bridge. This co-localization facilitated an important inter-domain interaction and was essential for efficient helper-mediated sat RNA accumulation in protoplasts. These results indicate that the tombusvirus sat RNA and helper genome contain structurally and functionally equivalent RNA domains. It is proposed that the limited sequence identity observed between these corresponding higher-order RNA structures is related to a strategy that reduces the induction of gene silencing, which presumably would be detrimental to both viral and sat RNA replicons.     

Radiation-induced DNA damage and its repair in lymphocytes of patients with head and neck cancer and healthy donors

BACKGROUND: DNA repair capacity may be an important factor in determining both individual susceptibility to cancer and the response to cancer therapy. The aim of this work was to compare DNA damage and the repair process in cells originating from healthy donors and cancer patients. MATERIALS AND METHODS: Using the micronucleus and comet assays, we compared the induction of DNA damage and its repair in lymphocytes isolated from blood samples of 14 healthy donors and 24 patients with head and neck tumours. Gamma-rays at the dose of 2 or 4 Gy were used as the damaging factor. The micronucleus test was performed according to Fenech (1) and the comet assay according to Green et al. (2). RESULTS AND CONCLUSION: Lymphocytes of both healthy donors and tumour patients showed great diversification in reaction to the same dose of gamma irradiation as well as differences in the kinetics of DNA repair. The patient group contained significantly more individuals whose lymphocytes were characterized by higher background DNA damage and higher damage inducibility. Blood cells of donors showing high damage inducibility also showed increased levels of micronuclei induced by ionizing radiation. Micronuclei induction did not correlate with a high level of unrepaired DNA damage.