Quinupristin-dalfopristin combined with beta-lactams for treatment of experimental endocarditis due to Staphylococcus aureus constitutively resistant to macrolide-lincosamide-streptogramin B antibiotics.

Quinupristin-dalfopristin (Q-D) is an injectable streptogramin active against most gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). In experimental endocarditis, however, Q-D was less efficacious against MRSA isolates constitutively resistant to macrolide-lincosamide-streptogram B (C-MLS(B)) than against MLS(B)-susceptible isolates. To circumvent this problem, we used the checkerboard method to screen drug combinations that would increase the efficacy of Q-D against such bacteria. beta-Lactams consistently exhibited additive or synergistic activity with Q-D. Glycopeptides, quinolones, and aminoglycosides were indifferent. No drugs were antagonistic. The positive Q-D-beta-lactam interaction was independent of MLS(B) or beta-lactam resistance. Moreover, addition of Q-D at one-fourth the MIC to flucloxacillin-containing plates decreased the flucloxacillin MIC for MRSA from 500 to 1,000 mg/liter to 30 to 60 mg/liter. Yet, Q-D-beta-lactam combinations were not synergistic in bactericidal tests. Rats with aortic vegetations were infected with two C-MLS(B)-resistant MRSA isolates (isolates AW7 and P8) and were treated for 3 or 5 days with drug dosages simulating the following treatments in humans: (i) Q-D at 7 mg/kg two times a day (b.i.d.) (a relatively low dosage purposely used to help detect positive drug interactions), (ii) cefamandole at constant levels in serum of 30 mg/liter, (iii) cefepime at 2 g b.i.d., (iv) Q-D combined with either cefamandole or cefepime. Any of the drugs used alone resulted in treatment failure. In contrast, Q-D plus either cefamandole or cefepime significantly decreased valve infection compared to the levels of infection for both untreated controls and those that received monotherapy (P < 0.05). Importantly, Q-D prevented the growth of highly beta-lactam-resistant MRSA in vivo. The mechanism of this beneficial drug interaction is unknown. However, Q-D-beta-lactam combinations might be useful for the treatment of complicated infections caused by multiple organisms, including MRSA.

Thermogenic effect of the new beta-adrenoreceptor agonist Ro 16-8714 in healthy male volunteers.

Previous investigations in experimental animals have shown that a new type of beta-adrenoceptor agonist (Ro 16-8714) possesses both thermogenic and antihyperglycemic properties. The aim of the study was to assess the thermogenic capacity of the compound in man after acute administration. Following an overnight fast three different doses (5, 10 and 20 mg) and a placebo were given per os to six normal-weight young men. The rate of energy expenditure (EE) and substrate utilization were determined by indirect calorimetry (hood system) before and for 6 h following the drug administration. Heart rate and blood pressure as well as plasma glucose, insulin and free fatty acid (FFA) concentrations were also measured at regular intervals throughout the study. The increment relative to base-line (mean +/- s.e.m.) in EE with placebo, 5, 10 and 20 mg was 4 +/- 3, 10 +/- 2, 11 +/- 2 and 21 +/- 2 percent respectively whereas heart rate was enhanced by 2 +/- 2, 8 +/- 3, 22 +/- 2, and 49 +/- 8 percent. Systolic blood pressure increased less (1 +/- 2, 8 +/- 1, 11 +/- 1 and 13 +/- 2 percent), and diastolic blood pressure did not change significantly. Simultaneously we observed a slight and transient increase in blood glucose, insulin and FFA concentrations. It is concluded that in lean individuals Ro 16-8714 is a potent thermogenic agent; however, new beta-adrenoceptor agonists should be developed in order to avoid the tachycardia associated with the thermogenic effect.

Horizontal transfer of exosomal microRNAs transduce apoptotic signals between pancreatic beta-cells.

BACKGROUND: Diabetes mellitus is a common metabolic disorder characterized by dysfunction of insulin-secreting pancreatic beta-cells. MicroRNAs are important regulators of beta-cell activities. These non-coding RNAs have recently been discovered to exert their effects not only inside the cell producing them but, upon exosome-mediated transfer, also in other recipient cells. This novel communication mode remains unexplored in pancreatic beta-cells. In the present study, the microRNA content of exosomes released by beta-cells in physiological and physiopathological conditions was analyzed and the biological impact of their transfer to recipient cells investigated. RESULTS: Exosomes were isolated from the culture media of MIN6B1 and INS-1 derived 832/13 beta-cell lines and from mice, rat or human islets. Global profiling revealed that the microRNAs released in MIN6B1 exosomes do not simply reflect the content of the cells of origin. Indeed, while a subset of microRNAs was preferentially released in exosomes others were selectively retained in the cells. Moreover, exposure of MIN6B1 cells to inflammatory cytokines changed the release of several microRNAs. The dynamics of microRNA secretion and their potential transfer to recipient cells were next investigated. As a proof-of-concept, we demonstrate that if cel-miR-238, a C. Elegans microRNA not present in mammalian cells, is expressed in MIN6B1 cells a fraction of it is released in exosomes and is transferred to recipient beta-cells. Furthermore, incubation of untreated MIN6B1 or mice islet cells in the presence of microRNA-containing exosomes isolated from the culture media of cytokine-treated MIN6B1 cells triggers apoptosis of recipient cells. In contrast, exosomes originating from cells not exposed to cytokines have no impact on cell survival. Apoptosis induced by exosomes produced by cytokine-treated cells was prevented by down-regulation of the microRNA-mediating silencing protein Ago2 in recipient cells, suggesting that the effect is mediated by the non-coding RNAs. CONCLUSIONS: Taken together, our results suggest that beta-cells secrete microRNAs that can be transferred to neighboring beta-cells. Exposure of donor cells to pathophysiological conditions commonly associated with diabetes modifies the release of microRNAs and affects survival of recipient beta-cells. Our results support the concept that exosomal microRNAs transfer constitutes a novel cell-to-cell communication mechanism regulating the activity of pancreatic beta-cells.

Delayed presentation of deep penetrating trauma to the subaxial cervical spine.

PURPOSE: To present a rare case of deep penetrating neck trauma in which a retained foreign body in the cervical spine (a broken knife blade) resulted in delayed radicular injury. We describe the surgical management using a retrojugular approach. CASE REPORT: Our patient sustained a stab wound to the supraclavicular triangle from a small pocketknife. He was initially managed in a local hospital by simple primary wound closure without any radiological examinations, and was discharged home. The patient re-consulted in a delayed fashion with mild local persistent neck pain. Subsequent radiological investigations revealed a foreign body (the broken blade of a pocket knife) embedded in the left neural foramen between the C6 and C7 vertebrae penetrating the disc space. The blade was lying between the left C7 nerve root and the ipsilateral vertebral artery (VA) at the transition of V1 and V2 segments. Initial neurological evaluation was normal. Some days later, the patient developed a delayed left C7 radicular deficit. We undertook urgent exploration along the wound corridor through a retrojugular, transforaminal approach with successful removal of the blade. DISCUSSION: To our knowledge, this is a unique case where a retained foreign body penetrated the soft tissues of the neck, embedding deep in the vertebral column without vascular, aerodigestive or significant primary neurological injury, while causing delayed neck pain and delayed onset radicular injury. We describe our surgical management for removal of the retained blade. The retrojugular approach gives excellent access to all of the important anatomical structures of the neck from an anterolateral approach.

Nuclear receptor peroxisome proliferator activated receptor (PPAR) beta/delta in skin wound healing and cancer

We review the functions of peroxisome proliferator activated receptor (PPAR) beta/delta in skin wound healing and cancer. In particular, we highlight the roles of PPAR beta/delta in inhibiting keratinocyte apoptosis at wound edges via activation of the PI3K/PKB alpha/Akt1 pathway and its role during re-epithelialization in regulating keratinocyte adhesion and migration. In fibroblasts, PPAR beta/delta controls IL-1 signalling and thereby contributes to the homeostatic control of keratinocyte proliferation. We discuss its therapeutic potential for treating diabetic wounds and inflammatory skin diseases such as psoriasis and acne vulgaris. PPAR beta/delta is classified as a tumour growth modifier; it is activated by chronic low-grade inflammation, which promotes the production of lipids that, in turn, enhance PPAR beta/delta transcription activity. Our earlier,work unveiled a cascade of events triggered by PPAR beta/delta that involve the oncogene Src, which promotes ultraviolet-induced skin cancer in mice via enhanced EGFR/Erk1/2 signalling and the expression of epithelial-to-mesenchymal transition (EMT) markers. Interestingly, PPAR beta/delta expression is correlated with the expression of SRC and EMT markers in human skin squamous cell carcinoma. Furthermore, there is a positive interaction between PPAR beta/delta, SRC, and TGF beta 1 at the transcriptional level in various human epithelial cancers. Taken together, these observations suggest the need for evaluating PPAR beta/delta modulators that attenuate or increase its activity, depending on the therapeutic target.

The use of beta-blockers is associated with the occurrence of acute kidney injury in severe alcoholic hepatitis.

BACKGROUND & AIMS: The beneficial effect of nonselective beta-blockers (NSBB) has recently been questioned in patients with end-stage cirrhosis. We analysed the impact of NSBB on outcomes in severe alcoholic hepatitis (AH). METHODS: This study was based on a prospective database of patients with severe, biopsy-proven AH. Patients admitted from July, 2006 to July, 2014 were retrospectively studied. Patients were divided into two groups (with and without NSBB) and assessed for the occurrence of Acute Kidney Injury (AKI) and transplant-free mortality during a 168-day follow-up period. RESULTS: One hundred thirty-nine patients were included, the mean Maddrey score was 71 ± 34 and 86 patients (61.9%) developed AKI. Forty-eight patients (34.5%) received NSBB. The overall 168-day transplant-free mortality was 50.5% (95%CI, 41.3-60.0%). The overall 168-day cumulative incidence of AKI was 61.9% (95%CI, 53.2-69.4%). When compared, patients with NSBB had a lower heart rate (65 ± 13 vs 92 ± 12, P < 0.0001) and a lower mean arterial pressure (MAP, 78 ± 3 vs 87 ± 5, P < 0.0001). Patients with NSBB had comparable MELD scores, Maddrey scores, and medical histories. The 168-day transplant-free mortality was 56.8% (95%CI, 41.3-69.7%) in patients with NSBB and 46.7% (95%CI, 35.0-57.6%) without NSBB (P = 0.25). The 168-day cumulative incidence of AKI was 89.6% (95%CI, 74.9-95.9%) with NSBB compared to 50.4% (95%CI: 39.0-60.7) for no NSBB (P = 0.0001). The independent factors predicting AKI were a higher MELD score and the presence of NSBB. CONCLUSIONS: The use of NSBB in patients with severe AH is independently associated with a higher cumulative incidence of AKI.

Involvement of long non-coding RNAs in beta cell failure at the onset of type 1 diabetes in NOD mice.

AIMS/HYPOTHESIS: Exposure of pancreatic beta cells to cytokines released by islet-infiltrating immune cells induces alterations in gene expression, leading to impaired insulin secretion and apoptosis in the initial phases of type 1 diabetes. Long non-coding RNAs (lncRNAs) are a new class of transcripts participating in the development of many diseases. As little is known about their role in insulin-secreting cells, this study aimed to evaluate their contribution to beta cell dysfunction. METHODS: The expression of lncRNAs was determined by microarray in the MIN6 beta cell line exposed to proinflammatory cytokines. The changes induced by cytokines were further assessed by real-time PCR in islets of control and NOD mice. The involvement of selected lncRNAs modified by cytokines was assessed after their overexpression in MIN6 cells and primary islet cells. RESULTS: MIN6 cells were found to express a large number of lncRNAs, many of which were modified by cytokine treatment. The changes in the level of selected lncRNAs were confirmed in mouse islets and an increase in these lncRNAs was also seen in prediabetic NOD mice. Overexpression of these lncRNAs in MIN6 and mouse islet cells, either alone or in combination with cytokines, favoured beta cell apoptosis without affecting insulin production or secretion. Furthermore, overexpression of lncRNA-1 promoted nuclear translocation of nuclear factor of κ light polypeptide gene enhancer in B cells 1 (NF-κB). CONCLUSIONS/INTERPRETATION: Our study shows that lncRNAs are modulated during the development of type 1 diabetes in NOD mice, and that their overexpression sensitises beta cells to apoptosis, probably contributing to their failure during the initial phases of the disease.

Early versus delayed application of Thomas splints in patients with isolated femur shaft fractures: The benefits quantified.

AIMS: To investigate and quantify the clinical benefits of early versus delayed application of Thomas splints in patients with isolated femur shaft fractures. MATERIALS AND METHODS: Level IV retrospective clinical and radiological analysis of patients presenting from January to December 2012 at a Level 1 Trauma Unit. All skeletally mature patients with isolated femur shaft fractures independently of their mechanism of injury were included. Exclusion criteria were: ipsilateral fracture of the lower limb, neck and supracondylar femur fractures, periprosthetic and incomplete fractures. Their clinical records were analysed for blood transfusion requirements, pulmonary complications, surgery time, duration of hospital stay and analgesic requirements. RESULTS: A total of 106 patients met our inclusion criteria. There were 74 males and 32 females. Fifty seven (54%) patients were in the 'early splinted' group and 49 patients (46%) were in the 'delayed splinted' group (P>0.05). The need for blood transfusion was significantly reduced in the 'early splinted' group (P=0.04). There was a significantly higher rate of pulmonary complications in the 'delayed splinted' group (P=0.008). All other parameters were similar between the two groups. CONCLUSION: The early application of Thomas splints for isolated femur fractures in non-polytraumatised patients has a clinically and statistically significant benefit of reducing the need for blood transfusions and the incidence of pulmonary complications.