Redistribution Of Air Within The Lungs May Potentiate "Fright" Bradycardia In Submerged Crocodiles (Crocodylus porosus)

1. Voluntary undisturbed dives by Crocodylus porosus were short in duration (3.08 + 1.87 min, mean + SD) and accompanied by a small but significant bradycardia (14.3 + 5.9% drop). 2. When crocodiles were disturbed underwater there was a rapid onset of "fright" bradycardia, to 65 + 6.0% of surface heart rates and dive durations were prolonged to 19.6 + 1.8 min. 3. The development of "fright" bradycardia was not accompanied by any increase in intratracheal pressure or expulsion of lung gas. However, sustained contraction of the abdomen and expansion of the thorax revealed a redistribution of air anteriorly within the lungs. 4. We propose that the redistribution of air within the lungs may generate an afferent signal which potentiates the initiation of a severe, dive-prolonging bradycardia

The Sub-Pulmonary Conus And The Arterial Anastomosis As Important Sites Of Cardiovascular Regulation In The Crocodile Crocodylus porosus

We present evidence to support the hypothesis that the arterial anastomosis and the cogteeth-like valves located in the sub-pulmonary conus in the right ventricle are important sites of cardiovascular regulation in the crocodile Crocodylus porosus. The influence of the arterial anastomosis on the development of the 'foramen spike' in the left aortic pressure trace, which occurs at the onset of diastole when the pressures in the right and left aortas become equal, and on gastrointestinal blood flow was examined in unanaesthetised C. porosus using blood vessel occluders. Measurements of blood flow in the arterial anastomosis showed that, during non-shunting conditions, there was a substantial systolic blood flow from the right aorta into the coeliac artery. The total coeliac artery blood flow was the sum of the anastomosis flow from the right aorta plus the left aortic flow originating from the right aorta via the foramen of Panizza during diastole. During mechanically induced pulmonary-to-systemic shunting, the anastomosis blood flow was reversed, with blood flowing from the left to the right aorta. The magnitude of the 'foramen spike' was directly related to the vascular resistance in the anastomosis. When vascular resistance in the anastomosis was high, such as during mechanical occlusion, there was an increase in the right aortic to left aortic pressure gradient during systole which resulted in an increase the foramen spike amplitude. Recordings of right intraventricular pressure in unanaesthetised C. porosus showed spontaneous changes in right intracardiac systolic pressure. The pressure recordings were biphasic, with the second contraction (isometric) being highly variable in size, indicating the control of pulmonary outflow resistance, possibly via the 'cogteeth valves' located in the sub-pulmonary conus in the right ventricle

Transcriptomes of parents identify parenting strategies and sexual conflict in a subsocial beetle

This work was funded by UK NERC grants to M.G.R. and A.J.M. an NERC studentship to D.J.P. the University of Georgia and a US NSF grant to A.J.M. and M.G.R.Parenting in the burying beetle Nicrophorus vespilloides is complex and, unusually, the sex and number of parents that can be present is flexible. Such flexibility is expected to involve specialized behaviour by the two sexes under biparental conditions. Here, we show that offspring fare equally well regardless of the sex or number of parents present. Comparing transcriptomes, we find a largely overlapping set of differentially expressed genes in both uniparental and biparental females and in uniparental males including vitellogenin, associated with reproduction, and takeout, influencing sex-specific mating and feeding behaviour. Gene expression in biparental males is similar to that in non-caring states. Thus, being ‘biparental’ in N. vespilloides describes the family social organization rather than the number of directly parenting individuals. There was no specialization; instead, in biparental families, direct male parental care appears to be limited with female behaviour unchanged. This should lead to strong sexual conflict.Publisher PDFPeer reviewe

Early Contrast Enhancement: a novel Magnetic Resonance Imaging biomarker of pleural malignancy

Introduction: Pleural Malignancy (PM) is often occult on subjective radiological assessment. We sought to define a novel, semi-objective Magnetic Resonance Imaging (MRI) biomarker of PM, targeted to increased tumour microvessel density (MVD) and applicable to minimal pleural thickening. Materials and methods: 60 consecutive patients with suspected PM underwent contrast-enhanced 3-T MRI then pleural biopsy. In 58/60, parietal pleura signal intensity (SI) was measured in multiple regions of interest (ROI) at multiple time-points, generating ROI SI/time curves and Mean SI gradient (MSIG: SI increment/time). The diagnostic performance of Early Contrast Enhancement (ECE; which was defined as a SI peak in at least one ROI at or before 4.5 min) was compared with subjective MRI and Computed Tomography (CT) morphology results. MSIG was correlated against tumour MVD (based on Factor VIII immunostain) in 31 patients with Mesothelioma. Results: 71% (41/58) patients had PM. Pleural thickening was <10 mm in 49/58 (84%). ECE sensitivity was 83% (95% CI 61–94%), specificity 83% (95% CI 68–91%), positive predictive value 68% (95% CI 47–84%), negative predictive value 92% (78–97%). ECE performance was similar or superior to subjective CT and MRI. MSIG correlated with MVD (r = 0.4258, p = .02). Discussion: ECE is a semi-objective, perfusion-based biomarker of PM, measurable in minimal pleural thickening. Further studies are warranted

Spectral isolation of naturally reductive metrics on simple Lie groups

We show that within the class of left-invariant naturally reductive metrics $\mathcal{M}_{\operatorname{Nat}}(G)$ on a compact simple Lie group $G$, every metric is spectrally isolated. We also observe that any collection of isospectral compact symmetric spaces is finite; this follows from a somewhat stronger statement involving only a finite part of the spectrum.Comment: 19 pages, new title and abstract, revised introduction, new result demonstrating that any collection of isospectral compact symmetric spaces must be finite, to appear Math Z. (published online Dec. 2009

Transmission in double quantum dots in the Kondo regime: Quantum-critical transitions and interference effects

We study the transmission through a double quantum-dot system in the Kondo regime. An exact expression for the transmission coefficient in terms of fully interacting many-body Green's functions is obtained. By mapping the system into an effective Anderson impurity model, one can determine the transmission using numerical renormalization-group methods. The transmission exhibits signatures of the different Kondo regimes of the effective model, including an unusual Kondo phase with split peaks in the spectral function, as well as a pseudogapped regime exhibiting a quantum critical transition between Kondo and unscreened phases.Comment: 4 pages, 3 figures; Submitted to Physica E (EP2DS-17 proceedings, oral presentation), updated Ref

A clinical pathway for total shoulder arthroplasty-a pilot study

BACKGROUND: Appropriate pain management after total shoulder arthroplasty (TSA) facilitates rehabilitation and may improve clinical outcomes.; QUESTIONS/PURPOSES: This prospective, observational study evaluated a multimodal analgesia clinical pathway for TSA.; METHODS: Ten TSA patients received an interscalene nerve block (25cm(3) 0.375% ropivacaine) with intraoperative general anesthesia. Postoperative analgesia included regularly scheduled non-opioid analgesics (meloxicam, acetaminophen, and pregabalin) and opioids on demand (oral oxycodone and intravenous patient-controlled hydromorphone). Patients were evaluated twice daily to assess pain, anterior deltoid strength, handgrip strength, and sensory function.; RESULTS: The nerve block lasted an average of 18h. Patients had minimal pain after surgery; 0 (median score on a 0-10 scale) in the Post-Anesthesia Care Unit (PACU) but increased on postoperative day (POD) 1 to 2.3 (0.0, 3.8; median (25%, 75%)) at rest and 3.8 (2.1, 6.1) with movement. Half of the patients activated the patient-controlled analgesia four or fewer times in the first 24h after surgery. Operative anterior deltoid strength was 0 in the PACU but returned to 68% by POD 1. Operative hand strength was 0 (median) in the PACU, but the third quartile (75%) had normalized strength 49% of preoperative value.; CONCLUSIONS: Patients did well with this multimodal analgesic protocol. Pain scores were low, half of the patients used little or no intravenous opiate, and some patients had good handgrip strength. Future research can focus on increasing duration of analgesia from the nerve block, minimizing motor block, lowering pain scores, and avoiding intravenous opioids

Candida albicans biofilm heterogeneity does not influence denture stomatitis but strongly influences denture cleansing capacity

Approximately 20  % of the UK population wear some form of denture prosthesis, resulting in denture stomatitis in half of these individuals. Candida albicans is primarily attributed as the causative agent, due to its biofilm -forming ability. Recently, there has been increasing evidence of C. albicans biofilm heterogeneity and the negative impact it can have clinically; however, this phenomenon has yet to be studied in relation to denture isolates. The aims of this study were to evaluate C. albicans biofilm formation of clinical denture isolates in a denture environment and to assess antimicrobial activity of common denture cleansers against these tenacious communities. C. albicans isolated from dentures of healthy and diseased individuals was quantified using real-time PCR and biofilm biomass assessed using crystal violet. Biofilm development on the denture substratum poly(methyl methacrylate), Molloplast B and Ufi-gel was determined. Biofilm formation was assessed using metabolic and biomass stains, following treatment with denture hygiene products. Although C. albicans was detected in greater quantities in diseased individuals, it was not associated with increased biofilm biomass. Denture substrata were shown to influence biofilm biomass, with poly(methyl methacrylate) providing the most suitable environment for C. albicans to reside. Of all denture hygiene products tested, Milton had the most effective antimicrobial activity, reducing biofilm biomass and viability the greatest. Overall, our results highlight the complex nature of denture- related disease, and disease development cannot always be attributed to a sole cause. It is the distinct combination of various factors that ultimately determines the pathogenic outcome

Non-immunological complications following kidney transplantation [version 1; referees: 3 approved]

Kidney transplantation (KT) is the most effective way to decrease the high morbidity and mortality of patients with end-stage renal disease. However, KT does not completely reverse the damage done by years of decreased kidney function and dialysis. Furthermore, new offending agents (in particular, immunosuppression) added in the post-transplant period increase the risk of complications. Cardiovascular (CV) disease, the leading cause of death in KT recipients, warrants pre-transplant screening based on risk factors. Nevertheless, the screening methods currently used have many shortcomings and a perfect screening modality does not exist. Risk factor modification in the pre- and post-transplant periods is of paramount importance to decrease the rate of CV complications post-transplant, either by lifestyle modification (for example, diet, exercise, and smoking cessation) or by pharmacological means (for example, statins, anti-hyperglycemics, and so on). Post-transplantation diabetes mellitus (PTDM) is a major contributor to mortality in this patient population. Although tacrolimus is a major contributor to PTDM development, changes in immunosuppression are limited by the higher risk of rejection with other agents. Immunosuppression has also been implicated in higher risk of malignancy; therefore, proper cancer screening is needed. Cancer immunotherapy is drastically changing the way certain types of cancer are treated in the general population; however, its use post-transplant is limited by the risk of allograft rejection. As expected, higher risk of infections is also encountered in transplant recipients. When caring for KT recipients, special attention is needed in screening methods, preventive measures, and treatment of infection with BK virus and cytomegalovirus. Hepatitis C virus infection is common in transplant candidates and in the deceased donor pool; however, newly developed direct-acting antivirals have been proven safe and effective in the pre- and post-transplant periods. The most important and recent developments on complications following KT are reviewed in this article