N-break states in a chain of nonlinear oscillators.

In the present work we explore a prestretched oscillator chain where the nodes interact via a pairwise Lennard-Jones potential. In addition to a homogeneous solution, we identify solutions with one or more (so-called) "breaks," i.e., jumps. As a function of the canonical parameter of the system, namely, the precompression strain d, we find that the most fundamental one-break solution changes stability when the monotonicity of the Hamiltonian changes with d. We provide a proof for this (motivated by numerical computations) observation. This critical point separates stable and unstable segments of the one-break branch of solutions. We find similar branches for two- through five-break branches of solutions. Each of these higher "excited state" solutions possesses an additional unstable pair of eigenvalues. We thus conjecture that k-break solutions will possess at least k-1 (and at most k) pairs of unstable eigenvalues. Our stability analysis is corroborated by direct numerical computations of the evolutionary dynamics.

A new genome scan for primary nonsyndromic vesicoureteric reflux emphasizes high genetic heterogeneity and shows linkage and association with various genes already implicated in urinary tract development.

Primary vesicoureteric reflux (VUR), the retrograde flow of urine from the bladder toward the kidneys, results from a developmental anomaly of the vesicoureteric valve mechanism, and is often associated with other urinary tract anomalies. It is the most common urological problem in children, with an estimated prevalence of 1-2%, and is a major cause of hypertension in childhood and of renal failure in childhood or adult life. We present the results of a genetic linkage and association scan using 900,000 markers. Our linkage results show a large number of suggestive linkage peaks, with different results in two groups of families, suggesting that VUR is even more genetically heterogeneous than previously imagined. The only marker achieving P < 0.02 for linkage in both groups of families is 270 kb from EMX2. In three sibships, we found recessive linkage to KHDRBS3, previously reported in a Somali family. In another family we discovered sex-reversal associated with VUR, implicating PRKX, for which there was weak support for dominant linkage in the overall data set. Several other candidate genes are suggested by our linkage or association results, and four of our linkage peaks are within copy-number variants recently found to be associated with renal hypodysplasia. Undoubtedly there are many genes related to VUR. Our study gives support to some loci suggested by earlier studies as well as suggesting new ones, and provides numerous indications for further investigations.

Giant rectal gastrointestinal stromal tumours: a diagnostic and therapeutic challenge.

Gastrointestinal stromal tumour (GIST are the most common mesenchymal tumours; however, rectal GISTs account for <5%. In the pelvis they represent a diagnostic challenge with giant GISTs likely to be malignant. They may present with urological, gynaecological or rectal symptoms. Sphincter-preserving surgery can be aided by neoadjuvant therapy. We present an uncommon case of giant rectal GIST masquerading as acute urinary retention.

Metachronous bilateral adrenal metastases following curative treatment for colorectal carcinoma.

A delayed, metachronous presentation of bilateral adrenal metastases following colorectal cancer has never previously been reported. We describe the case of a 68-year-old man who underwent curative surgery and adjuvant chemotherapy for a locally invasive sigmoid adenocarcinoma, only to be diagnosed with metachronous bilateral adrenal metastasis necessitating further resection and chemotherapy. We discuss the literature surrounding this pathology and highlight the importance of continual, vigilant radiological surveillance of the adrenal glands after curative treatment of colorectal carcinoma with or without subsequent adrenal metastasis.

Minimally invasive surgical wound infections: laparoscopic surgery decreases morbidity of surgical site infections and decreases the cost of wound care.

AIM: The morbidity of surgical site infections (SSIs) were compared in patients who underwent open (OS) vs laparoscopic (LS) colorectal surgery. METHOD: Data from 603 consecutive LS patients and 2246 consecutive OS patients were prospectively recorded. Morbidity of SSIs was assessed by the need for emergency department (ED) evaluation, subsequent hospital re-admission and re-operation. The cost of wound care was measured by the need for home healthcare, wound vacuum assisted closure (VAC) or independent patient wound care. RESULTS: SSIs were identified in 5.8% (n = 25) of LS patients and 4.8% (n = 65) of OS patients. ED evaluation for the infection was needed in 24% of the LS group and 42% of the OS group. Hospital re-admission was needed in one LS patient and in 52% OS patients. No LS patient needed re-operation compared with 12% of OS patients. HHC ($162/dressing change) was required in 63% of the OS group compared with 8% of LS group. A home wound VAC system ($107/day) was utilized in 12% of the OS patients but in none of the LS patients. Dressing changes were managed independently by the patient in 92% of the LS compared with 37% of the OS patients. CONCLUSION: Laparoscopic colorectal surgery patients experience less morbidity when they develop SSIs incurring less cost compared with open colorectal surgery patients.

Priority water research questions as determined by UK practitioners and policy makers.

Several recent studies have emphasised the need for a more integrated process in which researchers, policy makers and practitioners interact to identify research priorities. This paper discusses such a process with respect to the UK water sector, detailing how questions were developed through inter-disciplinary collaboration using online questionnaires and a stakeholder workshop. The paper details the 94 key questions arising, and provides commentary on their scale and scope. Prioritization voting divided the nine research themes into three categories: (1) extreme events (primarily flooding), valuing freshwater services, and water supply, treatment and distribution [each >150/1109 votes]; (2) freshwater pollution and integrated catchment management [100-150 votes] and; (3) freshwater biodiversity, water industry governance, understanding and managing demand and communicating water research [50-100 votes]. The biggest demand was for research to improve understanding of intervention impacts in the water environment, while a need for improved understanding of basic processes was also clearly expressed, particularly with respect to impacts of pollution and aquatic ecosystems. Questions that addressed aspects of appraisal, particularly incorporation of ecological service values into decision making, were also strongly represented. The findings revealed that sustainability has entered the lexicon of the UK water sector, but much remains to be done to embed the concept operationally, with key sustainability issues such as resilience and interaction with related key sectors, such as energy and agriculture, relatively poorly addressed. However, the exercise also revealed that a necessary condition for sustainable development, effective communication between scientists, practitioners and policy makers, already appears to be relatively well established in the UK water sector.

High sodium and low potassium intake in patients with Type 2 diabetes.

AIMS: To document dietary sodium and potassium intake and adherence to the Australian National Heart Foundation (NHF) guidelines in patients with Type 2 diabetes mellitus attending an Australian tertiary referral and university teaching hospital. METHODS: In a longitudinal study, 24h urinary sodium (uNa), potassium (uK), creatinine (uCr), urea (uUrea) and glucose (uGlu) excretions, urine volume (uVol) and body mass index were recorded in 122 regular attenders over an 8 year period (2001-2008; mean of 1.9 samples/patient/year). In a cross-sectional study, the same measurements were recorded in patients providing urine samples in the month of June from 2001 to 2009 (782 patients, averaging 87/year). RESULTS: In the longitudinal study, uNa (mmol/24 h) was 170 ± 53 (mean ± SD) in males and 142 ± 51 in females, whereas uK (mmol/24 h) was 75 ± 22 in males and 62 ± 18 in females. Once adjusted for insensible losses, only 3% of males and 14% of females met the NHF dietary sodium intake guidelines, and 14% of males and 3% of female patients met the NHF dietary potassium guidelines. Body mass index, uUrea, uVol and uGlu were independent predictors of uNa (adjusted r(2) =0.57, P<0.0001). The mean intra-individual coefficient of variation of the corrected uNa was 21 ± 1%. The cross-sectional study confirmed these findings, and no temporal trends were observed. There was no correlation with glycated haemoglobin to suggest natriuresis with hyperglycaemia. CONCLUSIONS: Most patients with Type 2 diabetes mellitus do not meet NHF sodium or potassium intake guidelines. A diet high in sodium and low in potassium may contribute to the development of hypertension and to resistance to blood-pressure-lowering therapies.

Traumatic anterior shoulder instability: current concepts in management.

This review will give an overview of the current management practice and ethos of recurrent anterior shoulder instability, a condition which continues to puzzle and intrigue the shoulder surgeon.

Is there a role for magnetic resonance imaging in diagnosing colovesical fistulas?

OBJECTIVES: Colovesical fistula is a devastating complication, usually secondary to diverticulitis or colon cancer. Imaging plays a crucial role in delineating the underlying anatomy and identifying an etiologic factor. Barium enema, computed tomography, and cystoscopy have been the mainstays of investigation, but they have less than ideal sensitivity and specificity. This study assessed the role of magnetic resonance imaging (MRI) in the investigation of patients with probable colovesical fistulas. METHODS: A total of 22 patients with presentations suspicious for enterovesical fistulas who underwent evaluation with axial T(1)-weighted and axial, coronal, and sagittal T(2)-weighted 1.5T MRI (body-phased array) were identified. Of the 22 patients, 19 underwent laparotomy and repair. RESULTS: MRI correctly identified the presence of a fistula and defined the underlying etiology in 18 of 19 patients. Colovesical fistula was correctly excluded in 1 of 19 patients. The remaining 3 patients were either unfit for surgery or refused. CONCLUSIONS: The results of our study have shown that MRI is an accurate method of evaluating patients with suspicion of colovesical fistulas, identifying the anatomy of the tract, as well as the etiology. This is not only useful for diagnosis, but also for surgical planning.

Training the trainers.

Our understanding of how adults learn has undergone many advances in the last few years. This information needs to be used to build more effective training in anaesthesia throughout the world, especially in those countries where the need to train large numbers is critical to the development of effective medical services. Training a new generation of teachers is a key part of this.

Molecular analysis of Francisella tularensis subspecies tularensis and holarctica.

Rapid methods are needed for public health and military applications to specifically identify Francisella tularensis, the causative agent of tularemia in humans. A comparative analysis of the capabilities of multiple technologies was performed using a well-defined set of organisms to determine which approach would provide the most information in the shortest time. High-resolution molecular techniques, including pulsed-field gel electrophoresis, amplified fragment length polymorphism, and ribotyping, provided subspecies level identification within approximately 24 hours after obtaining an isolate, whereas multilocus variable number tandem repeat analysis with 8 or 25 targets provided strain level discrimination within about 12 hours. In contrast, Raman spectroscopy provided species level identification in 10 minutes but could not differentiate between subspecies tularensis and holarctica.

Genomic deletion marking an emerging subclone of Francisella tularensis subsp. holarctica in France and the Iberian Peninsula.

Francisella tularensis subsp. holarctica is widely disseminated in North America and the boreal and temperate regions of the Eurasian continent. Comparative genomic analyses identified a 1.59-kb genomic deletion specific to F. tularensis subsp. holarctica isolates from Spain and France. Phylogenetic analysis of strains carrying this deletion by multiple-locus variable-number tandem repeat analysis showed that the strains comprise a highly related set of genotypes, implying that these strains were recently introduced or recently emerged by clonal expansion in France and the Iberian Peninsula.

Impact of Helicobacter pylori on the management of dyspepsia in primary care.

BACKGROUND: It is unclear what impact Helicobacter pylori infection has had on the management of dyspepsia in primary care and to what extent published guidelines on H. pylori are implemented in routine clinical practice. AIM: To assess the impact of H. pylori infection on the management of dyspepsia in primary care. METHODS: Patients referred by primary care doctors to an open-access 13-carbon urea breath test service over a 2-year period for their first urea breath test were included in the study. Individual breath results were linked with data on prescribing obtained from the General Medical Services prescription database. RESULTS: Of 805 patients, 374 (47%) had a positive urea breath test and 431 (54%) a negative urea breath test. Of positive urea breath test patients, only 245 (64%) were prescribed eradication therapy in the 3 months after the breath test and only 43% were referred back for re-testing. In the year after the urea breath test, there was a significant fall in prescribing of antisecretory therapy which was greatest in the patients who received H. pylori therapy (P < 0.001). CONCLUSIONS: There appears to be under and inappropriate treatment of H. pylori infection in primary care, and a low rate of re-testing after eradication, indicating that current guidelines are not well implemented in practice.

MRI appearances of pelvic malakoplakia.

We report the MRI appearances in a patient with parametrial malakoplakia. The patient complained of pelvic pain and vaginal discharge. Physical examination revealed a "frozen" pelvis suggestive of malignancy. MRI showed bilateral parametrial "infiltration", but no overt primary pelvic tumour. The combination of these findings together with the inflammatory symptoms suggested an inflammatory condition. Malakoplakia was confirmed at resective biopsy.