Is prosthesis retention effective for chronic infections in hip arthroplasties? A systematic literature review

The success rate of prosthesis removal as the standard approach to manage chronic infection in hip arthroplasties (HA) is 80-90 %. The effectiveness of prosthesis retention, with or without surgical debridement, to treat patients with chronic HA infection (symptom duration of more than 4 weeks) has not been well established, whereas this strategy is sometimes used in clinical practice. This study aimed to explore the cumulative incidence of failure of chronic HA infections treated with prosthesis retention, with or without debridement. A systematic literature review was conducted in accordance with the methods described in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Studies concerning patients with chronically infected HA treated with prosthesis retention were included. The primary outcome was the cumulative risk of failure. We searched the MEDLINE, Embase, and Cochrane databases up to April 2014. The database searches provided a total of 1,213 studies for potential inclusion in the review. Six relevant studies were finally identified, corresponding to 29 patients included. Their treatments consisted of prosthesis retention with debridement. This strategy failed for 14 out of these 29 patients after a 1-year follow-up. The failure rate of the prosthesis retention approach associated to debridement for chronic infection in HA is 48.3 % in this review. Debridement and prosthesis retention in association with prolonged antimicrobial treatment may be an advantageous alternative to arthroplasty exchange for frail patients. The difficulty in finding relevant studies illustrates the challenges of interpreting the existing literature for the management of chronic prosthetic joint infection (PJI).

Organic molecules in the Sheepbed Mudstone, Gale Crater, Mars

The Sample Analysis at Mars (SAM) instrument on board the Mars Science Laboratory Curiosity rover is designed to conduct inorganic and organic chemical analyses of the atmosphere and the surface regolith and rocks to help evaluate the past and present habitability potential of Mars at Gale Crater. Central to this task is the development of an inventory of any organic molecules present to elucidate processes associated with their origin, diagenesis, concentration, and long-term preservation. This will guide the future search for biosignatures. Here we report the definitive identification of chlorobenzene (150-300 parts per billion by weight (ppbw)) and C₂ to C₄ dichloroalkanes (up to 70 ppbw) with the SAM gas chromatograph mass spectrometer (GCMS) and detection of chlorobenzene in the direct evolved gas analysis (EGA) mode, in multiple portions of the fines from the Cumberland drill hole in the Sheepbed mudstone at Yellowknife Bay. When combined with GCMS and EGA data from multiple scooped and drilled samples, blank runs, and supporting laboratory analog studies, the elevated levels of chlorobenzene and the dichloroalkanes cannot be solely explained by instrument background sources known to be present in SAM. We conclude that these chlorinated hydrocarbons are the reaction products of Martian chlorine and organic carbon derived from Martian sources (e.g., igneous, hydrothermal, atmospheric, or biological) or exogenous sources such as meteorites, comets, or interplanetary dust particles.

KEY POINTS

First in situ evidence of nonterrestrial organics in Martian surface sediments Chlorinated hydrocarbons identified in the Sheepbed mudstone by SAM Organics preserved in sample exposed to ionizing radiation and oxidative condition.

Organic molecules in the Sheepbed Mudstone, Gale Crater, Mars

The Sample Analysis at Mars (SAM) instrument on board the Mars Science Laboratory Curiosity rover is designed to conduct inorganic and organic chemical analyses of the atmosphere and the surface regolith and rocks to help evaluate the past and present habitability potential of Mars at Gale Crater. Central to this task is the development of an inventory of any organic molecules present to elucidate processes associated with their origin, diagenesis, concentration, and long-term preservation. This will guide the future search for biosignatures. Here we report the definitive identification of chlorobenzene (150-300 parts per billion by weight (ppbw)) and C₂ to C₄ dichloroalkanes (up to 70 ppbw) with the SAM gas chromatograph mass spectrometer (GCMS) and detection of chlorobenzene in the direct evolved gas analysis (EGA) mode, in multiple portions of the fines from the Cumberland drill hole in the Sheepbed mudstone at Yellowknife Bay. When combined with GCMS and EGA data from multiple scooped and drilled samples, blank runs, and supporting laboratory analog studies, the elevated levels of chlorobenzene and the dichloroalkanes cannot be solely explained by instrument background sources known to be present in SAM. We conclude that these chlorinated hydrocarbons are the reaction products of Martian chlorine and organic carbon derived from Martian sources (e.g., igneous, hydrothermal, atmospheric, or biological) or exogenous sources such as meteorites, comets, or interplanetary dust particles.

KEY POINTS

First in situ evidence of nonterrestrial organics in Martian surface sediments Chlorinated hydrocarbons identified in the Sheepbed mudstone by SAM Organics preserved in sample exposed to ionizing radiation and oxidative condition.

A protocol for testing expert-system reliability

We set out a protocol for giving a computerised medical decision system the label of expert-system meaning that its responses are of the same standard as those of an expert. We apply it to the validation of an expert-system, MENINGE, which is applied to diagnosis of meningitis in children. The proposed protocol can be widely used since it doesn't refer to the existence of correct responses for therapy or diagnosis, and since it involves simple statistical computations. First this validation rests on a comparison of agreement among experts and among physicians new to medical practice. Secondly, the agreement of the system with the experts is compared to the agreement of the system with physicians new to medical practice. In order to perform this comparison we recommend a standard agreement measure, the choice of which is an important issue in this paper.

[Evaluation of an obesity prevention program for school-aged children in deprived urban areas]

OBJECTIVE

Increasing prevalence of obesity particularly affects underprivileged families and children. This study aimed to estimate the efficiency of an obesity prevention program for school-aged children in deprived urban areas.

METHODS

This was an intervention trial with a before-and-after comparison of a cohort of school-aged children in preschool and primary school in three deprived urban areas in Grenoble, France. All school-aged children in the first and third year of preschool and the third year of primary school during the 2008-2009 and 2009-2010 school years, whose parents agreed to participate in the study, were included. Children were seen again 2 years later. The staff of the school health service measured and weighed the children during a medical check-up, thus determining their body mass index (BMI) and Z score. A school doctor suggested specific care to the parents of overweight children. A lifestyle questionnaire was completed. The primary outcome was changes in BMI and the Z score over 2 years. The secondary outcome was changes in lifestyle and eating habits.

RESULTS

A total of 2434 children were included in the screening campaign. Of the 2434 children included in screening, 1824 children were reviewed and evaluated at 2 years. At inclusion, overweight prevalence increased with age, from 6.4% in the first year of preschool to 21.9% in the third year of primary school. More than 60% of overweight children had a high social vulnerability score. Prevalence of overweight increased from 13.8% to 21.5% in 2 years in the entire cohort (P<0.001). In the 252 overweight children, the mean BMI increased from 20 kg/m(2) to 21.8 kg/m(2) (P<0.001), as did the mean Z score, which increased from 2.72 to 2.9 (P<0.001). There was no significant interaction depending on whether the family physician was in private practice or employed by a health center. According to their eating habits, fewer of the overweight children had a snack in the morning and more had a school lunch. More than half of the children thought they had improved their eating habits. They played more sports (30% versus 49.5%).

CONCLUSION

This study failed to demonstrate that incentive for medical management of excess weight had an effect on the short-term (2 years) evolution of the children's corpulence.

Evolving phenotypic networks in silico

Evolved gene networks are constrained by natural selection. Their structures and functions are consequently far from being random, as exemplified by the multiple instances of parallel/convergent evolution. One can thus ask if features of actual gene networks can be recovered from evolutionary first principles. I review a method for in silico evolution of small models of gene networks aiming at performing predefined biological functions. I summarize the current implementation of the algorithm, insisting on the construction of a proper "fitness" function. I illustrate the approach on three examples: biochemical adaptation, ligand discrimination and vertebrate segmentation (somitogenesis). While the structure of the evolved networks is variable, dynamics of our evolved networks are usually constrained and present many similar features to actual gene networks, including properties that were not explicitly selected for. In silico evolution can thus be used to predict biological behaviours without a detailed knowledge of the mapping between genotype and phenotype.

Pneumocystis jirovecii (Pj) quantitative PCR to differentiate Pj pneumonia from Pj colonization in immunocompromised patients

Conventional polymerase chain reaction (PCR) in respiratory samples does not differentiate between Pneumocystis pneumonia (PCP) and Pneumocystis jirovecii (Pj) colonization. We used Pj real-time quantitative PCR (qPCR) with the objective to discriminate PCP from Pj colonization in immunocompromised patients. All positive Pj qPCR [targeting the major surface glycoprotein (MSG) gene] obtained in respiratory samples from immunocompromised patients presenting pneumonia at the Grenoble University Hospital, France, were collected between August 2009 and April 2011. Diagnoses were retrospectively determined by a multidisciplinary group of experts blinded to the Pj qPCR results. Thirty-one bronchoalveolar lavages and four broncho aspirations positive for the Pj qPCR were obtained from 35 immunocompromised patients. Diagnoses of definite, probable, and possible PCP, and pneumonia from another etiology were retrospectively made for 7, 4, 5, and 19 patients, respectively. Copy numbers were significantly higher in the “definite group” (median 465,000 copies/ml) than in the “probable group” (median 38,600 copies/ml), the “possible group” (median 1,032 copies/ml), and the “other diagnosis group” (median 390 copies/ml). With the value of 3,160 copies/ml, the sensitivity and specificity of qPCR for the diagnosis of PCP were 100 % and 70 %, respectively. With the value of 31,600 copies/ml, the sensitivity and specificity were 80 % and 100 %, respectively. The positive predictive value was 100 % for results with more than 31,600 copies/ml and the negative predictive value was 100 % for results with fewer than 3,160 copies/ml. qPCR targeting the MSG gene can be helpful to discriminate PCP from Pj colonization in immunocompromised patients, using two cut-off values, with a gray zone between them.

[Ptosis secondary to cavernous sinus meningioma]

INTRODUCTION

Meningiomas of the cavernous sinus are often the cause of neuro-ophthalmologic manifestations. Fifty percent of affected patients present with ptosis. We report a case of ptosis acquired during the first year of life due to oculomotor nerve palsy secondary to a cavernous sinus meningioma. We then discuss the causes of third cranial nerve palsy and treatment options for ptosis associated with CN III palsy.

OBSERVATION

A fifteen-year-old female patient presented with ptosis due to a third cranial nerve palsy appearing within the first year of life. Magnetic resonance imaging (MRI) revealed a cavernous sinus meningioma. The ptosis was treated by frontalis suspension using autologous temporalis fascia. The meningioma required regular follow-up.

DISCUSSION

Ptosis due to third cranial nerve palsy is rare in children. The most common etiologies are congenital and represent 33 to 40% of cases in various studies. Other etiologies are traumatic, tumoral, vascular and infectious. The cause needs to be found by imaging over the entire course of the nerve. Cavernous sinus meningioma is one cause of third cranial nerve palsy. The surgical treatment of ptosis due to third cranial nerve palsy is levator resection or frontalis suspension with a strip of fascia lata or temporalis fascia.

Principles of adaptive sorting revealed by in silico evolution

Many biological networks have to filter out useful information from a vast excess of spurious interactions. In this Letter, we use computational evolution to predict design features of networks processing ligand categorization. The important problem of early immune response is considered as a case study. Rounds of evolution with different constraints uncover elaborations of the same network motif we name "adaptive sorting." Corresponding network substructures can be identified in current models of immune recognition. Our work draws a deep analogy between immune recognition and biochemical adaptation.

Anterior fossa schwannoma mimicking an olfactory groove meningioma: case report and literature review

Intracranial schwannomas not associated with cranial nerves account for less than 1% of surgically treated schwannomas of the central and peripheral nervous system. With only 45 cases reported to date, subfrontal schwannomas are very rare tumors, leaving the issue of their origin controversial. A 66-year-old woman presented with a 1-year history of progressive headaches. Clinical examination revealed hypoesthesia of the nasal tip. CT-scan and MRI studies revealed a large subfrontal tumor thought preoperatively to be a meningioma. Intraoperatively, a large extra-axial tumor arising from the floor of the right frontal fossa was encountered. Histopathology identified the tumor as a schwannoma. This current case gives strong clinical presumption of an origin from the anterior ethmoidal nerve. We reviewed the literature in order to establish the epidemiology of these tumors, from which there appear to be divergent profiles depending on tumor origin and histology. Despite close similarities with olfactory groove meningiomas, patient history and radiological findings provide substantial evidence for differential diagnosis.