The mismatch of narratives and local ecologies in the everyday governance of water access and mosquito control in an urbanizing community.

Mosquito-borne disease presents a significant threat to urban populations, but risk can be uneven across a city due to underlying environmental patterns. Urban residents rely on social and economic processes to control the environment and mediate disease risk, a phenomenon known as everyday governance. We studied how households employed everyday governance of urban infrastructure relevant to mosquito-borne disease in Bengaluru, India to examine if and how inequalities in everyday governance manifest in differences in mosquito control. We found that governance mechanisms differed for water access and mosquitoes. Economic and social capital served different roles for each, influenced by global narratives of water and vector control.

Design, Modelling and Teleoperation of a 2 mm Diameter Compliant Instrument for the da Vinci Platform.

This work explores the feasibility of creating and accurately controlling an instrument for robotic surgery with a 2 mm diameter and a three degree-of-freedom (DoF) wrist which is compatible with the da Vinci platform. The instrument's wrist is composed of a two DoF bending notched-nitinol tube pattern, for which a kinematic model has been developed. A base mechanism for controlling the wrist is designed for integration with the da Vinci Research Kit. A basic teleoperation task is successfully performed using two of the miniature instruments. The performance and accuracy of the instrument suggest that creating and accurately controlling a 2 mm diameter instrument is feasible and the design and modelling proposed in this work provide a basis for future miniature instrument development.

Characterizing the phylogenetic specialism-generalism spectrum of mammal parasites.

The distribution of parasites across mammalian hosts is complex and represents a differential ability or opportunity to infect different host species. Here, we take a macroecological approach to investigate factors influencing why some parasites show a tendency to infect species widely distributed in the host phylogeny (phylogenetic generalism) while others infect only closely related hosts. Using a database on over 1400 parasite species that have been documented to infect up to 69 terrestrial mammal host species, we characterize the phylogenetic generalism of parasites using standard effect sizes for three metrics: mean pairwise phylogenetic distance (PD), maximum PD and phylogenetic aggregation. We identify a trend towards phylogenetic specialism, though statistically host relatedness is most often equivalent to that expected from a random sample of host species. Bacteria and arthropod parasites are typically the most generalist, viruses and helminths exhibit intermediate generalism, and protozoa are on average the most specialist. While viruses and helminths have similar mean pairwise PD on average, the viruses exhibit higher variation as a group. Close-contact transmission is the transmission mode most associated with specialism. Most parasites exhibiting phylogenetic aggregation (associating with discrete groups of species dispersed across the host phylogeny) are helminths and viruses.

Ultrasonic motor-induced geometric distortions in magnetic resonance images.

Ultrasonic motors (USMs) are common actuators that can be safely used in the magnetic resonance imaging (MRI) environment. However, lack of MRI compatibility results in issues such as image distortion. This fact led researchers to shift focus from USMs to pneumatic and hydraulic actuators in development of surgical robots. The aim is to quantify and compensate the geometric distortion of MR images as generated by the presence of USMs. An ultrasonic motor was positioned in three orientations with respect to the bore axis. The induced distortions were compared across four image sequences. To reduce the distortions, three artifact reduction methods were employed. Geometric distortion is the only artifact in image slices farther from the motor. The various motor orientations lead to different distortions, with the lowest distortion for the z orientation. The maximum measured distortion of ten pixels occurred. This maximal distortion is equal to a 1-cm displacement of the displayed points relative to their actual locations and it is beyond the acceptable level for medical display standards. Bandwidth reduction reduced the distortion, with a 50% reduction for a doubled bandwidth. In conclusion, USMs can be preferred alternative because accurate targeting of pathologies can occur in free distorted images.

ABCG2 loss-of-function polymorphism predicts poor response to allopurinol in patients with gout.

Many patients fail to achieve the recommended serum urate (SU) target (<6 mgdl-1) with allopurinol. The aim of our study was to examine the association of ABCG2 with SU target in response to standard doses of allopurinol using a cohort with confirmed adherence. Good response was defined as SU<6 mgdl-1 on allopurinol ⩽300 mgd-1 and poor response as SU⩾6 mgdl-1 despite allopurinol >300 mgd-1. Adherence was confirmed by oxypurinol concentrations. ABCG2 genotyping was performed using pre-designed single nucleotide polymorphism (SNP) TaqMan assays. Of 264 patients, 120 were good responders, 68 were poor responders and 76 were either non-adherent or could not be classified. The minor allele of ABCG2 SNP rs2231142 conferred a significantly increased risk of poor response to allopurinol (odds ratio=2.71 (1.70-4.48), P=6.0 × 10-5). This association remained significant after adjustment for age, sex, body mass index, ethnicity, estimated glomerular filtration rate, diuretic use and SU off urate-lowering therapy. ABCG2 rs2231142 predicts poor response to allopurinol, as defined by SU⩾6 mgdl-1 despite allopurinol >300 mgd-1.

Dissecting a wildlife disease hotspot: the impact of multiple host species, environmental transmission and seasonality in migration, breeding and mortality.

Avian influenza viruses (AIVs) have been implicated in all human influenza pandemics in recent history. Despite this, surprisingly little is known about the mechanisms underlying the maintenance and spread of these viruses in their natural bird reservoirs. Surveillance has identified an AIV 'hotspot' in shorebirds at Delaware Bay, in which prevalence is estimated to exceed other monitored sites by an order of magnitude. To better understand the factors that create an AIV hotspot, we developed and parametrized a mechanistic transmission model to study the simultaneous epizootiological impacts of multi-species transmission, seasonal breeding, host migration and mixed transmission routes. We scrutinized our model to examine the potential for an AIV hotspot to serve as a 'gateway' for the spread of novel viruses into North America. Our findings identify the conditions under which a novel influenza virus, if introduced into the system, could successfully invade and proliferate.

Critical patch size generated by Allee effect in gypsy moth, Lymantria dispar (L.).

Allee effects are important dynamical mechanisms in small-density populations in which per capita population growth rate increases with density. When positive density dependence is sufficiently severe (a 'strong' Allee effect), a critical density arises below which populations do not persist. For spatially distributed populations subject to dispersal, theory predicts that the occupied area also exhibits a critical threshold for population persistence, but this result has not been confirmed in nature. We tested this prediction in patterns of population persistence across the invasion front of the European gypsy moth (Lymantria dispar) in the United States in data collected between 1996 and 2008. Our analysis consistently provided evidence for effects of both population area and density on persistence, as predicted by the general theory, and confirmed here using a mechanistic model developed for the gypsy moth system. We believe this study to be the first empirical documentation of critical patch size induced by an Allee effect.

Upper limb motor function in young adults with spina bifida and hydrocephalus.

OBJECTIVE: The objective of the study was to measure upper limb motor function in young adults with spina bifida meningomyelocele (SBM) and typically developing age peers. METHOD: Participants were 26 young adults with SBM, with a Verbal or Performance IQ score of at least 70 on the Wechsler scales, and 27 age- and gender-matched controls. Four upper limb motor function tasks were performed under four different visual and cognitive challenge conditions. Motor independence was assessed by questionnaire. RESULTS: Fewer SBM than control participants obtained perfect posture and rebound scores. The SBM group performed less accurately and was more disrupted by cognitive challenge than controls on limb dysmetria tasks. The SBM group was slower than controls on the diadochokinesis task. Adaptive motor independence was related to one upper limb motor task, arm posture, and upper rather than lower spinal lesions were associated with less motor independence. CONCLUSIONS: Young adults with SBM have significant limitations in upper limb function and are more disrupted by some challenges while performing upper limb motor tasks. Within the group of young adults with SBM, upper spinal lesions compromise motor independence more than lower spinal lesions.

The constitutive properties of the brain parenchyma Part 1. Strain energy approach.

In this paper we study several constitutive equations for the brain based on the strain energy density function. We use the polynomial function and hyper-elastic Ogden model for the strain energy and include the energy dissipation by a Prony series expansion. The models are compared with known unconfined compression experimental results of the human brain tissue to obtain the best fitted model and brain mechanical parameters. Finite element simulations are also performed using the given constitutive equations, and numerical solutions match the analytical results very closely. The results are compared with other analytical and numerical calculations.

Fatal ethibloc embolization of vertebrobasilar system following percutaneous injection into aneurysmal bone cyst of the second cervical vertebra.

A 4-year-old boy developed progressive neck pain and an expansile osteogenic lesion of C2; the diagnosis was an aneurysmal bone cyst. An image-guided biopsy with 3D CT planning was performed followed by Ethibloc injection into the aneurysmal bone cyst. Subsequent CT and MR images demonstrated embolization material in the vertebrobasilar system, and the patient died of brain stem and cerebellar infarction 23 hours after the intervention. The course of events and technical considerations are discussed.

Rapid formation of a multi-compartment neonatal arachnoid cyst.

A 3-day-old term infant born via vaginal delivery presented with irritability and tachypnoea. Cranial ultrasound, CT and MRI demonstrated a massive left temporal arachnoid cyst extending into the anterior and posterior fossa as well as the suprasellar area. In utero ultrasounds at 9.5, 19 and 32 weeks of gestation had been normal. Endoscopic exploration revealed that all cyst components were communicating, and a cystoperitoneal shunt was inserted with rapid resolution of symptoms and cyst decompression. Arachnoid cysts may develop rapidly in utero and may not be associated with underlying brain hypoplasia. Attempts at rapid and maximum decompression may be reasonable in this setting.

The role of sFRP4, a secreted frizzled-related protein, in ovulation.

Ovulation is a complex, multi-factorial event that involves the degeneration of a specific area of the follicular and ovarian surface via apoptosis. Many apoptosis related genes have been identified in the ovary. Secreted Frizzled Related Protein 4 (sFRP4) is a protein that appears to antagonize a molecular pathway for cell survival. sFRP4 gene expression is known to be upregulated with apoptosis in the ovarian corpus luteum. In this study, ovulation was hormonally induced in immature Wistar rats and their ovaries collected for analysis of apoptosis and sFRP4. TUNEL staining identified a greater amount of dying cells in the thecal layer of treated rat ovaries compared to controls. The results of 3'-end labelling revealed a significant increase (p < 0.01) in apoptosis at 12 hours following treatment compared to other time points and control. In situ hybridization exhibited a visible increase in amounts of sFRP4 mRNA expression in the thecal layers of follicles from treated rats compared to controls. Quantitative RT-PCR revealed no significant difference in sFRP4 expression levels between treated and control tissues although a clear trend towards an increase was observed in the treated group. This study demonstrates an association between sFRP4 and apoptosis in rat ovulation.

Medulloblastoma in a child with Rubenstein-Taybi Syndrome: case report and review of the literature.

Although medulloblastoma is usually sporadic, there are a number of uncommon predisposing germline mutation syndromes, including: Gorlin's Syndrome, Turcot's Syndrome and Li-Fraumeni Syndrome. Patients with Rubenstein-Taybi Syndrome secondary to mutation/deletion of the CBP gene on chromosome 16 are predisposed to a variety of developmental anomalies as well as cancer. We report a child with Rubenstein-Taybi syndrome who developed a cerebellar medulloblastoma and review the literature on Rubenstein-Taybi Syndrome and pediatric medulloblastoma. As the product of the CBP gene functions in a variety of signaling pathways, we discuss the molecular implications of findings a medulloblastoma in a child with Rubenstein-Taybi Syndrome.

Repeat cerebrospinal fluid shunt infection in children.

BACKGROUND: In this study, we investigated the treatment of cerebrospinal fluid (CSF) shunt infection and the risk factors for repeat shunt infection (RSI) in a cohort of children treated at the Hospital for Sick Children, Toronto, Canada. METHODS: Between 1996 and 2000, a total of 51 children were identified with shunt infection (mean age 5.8 years). The medical records of these children were reviewed to identify cases of RSI within 6 months of the initial shunt infection (ISI). RESULTS: In the 51 ISIs, the infecting organisms were coagulase-negative Staphylococcus (43.1%), Staphylococcus aureus (37.3%) and others (19.6%). The initial mode of treatment of the shunt infection was using an external ventricular drain (EVD) with removal of the shunt apparatus (54.9%), externalization of the shunt (37.3%) or shunt removal only (7.8%). The mean number of days of external CSF drainage (either EVD or externalized shunt) was 11.2 days. Ten patients (19.6%) developed RSI. The actuarial risk of RSI plateaued after 90 days at 24.4%. The following variables were tested as risk factors for RSI using survival analysis, although none reached statistical significance: initial organism (p = 0.09), age (p = 0.42), etiology of hydrocephalus (p = 0.45), number of days of CSF drainage (p = 0.45), type of surgical treatment of the ISI (p = 0.58) and the presence of bacteriologically positive CSF at ISI (p = 0.85). CONCLUSIONS: The risk of RSI is substantial and greater effort needs to be directed towards understanding the risk factors. Such studies will need a greater sample size in order to obtain sufficient statistical power.

Shunt malfunctions.

Shunt failure remains a disheartening complication of shunt surgery. The number of adjustable factors in attempting to reduce the rate is small. The clinical presentation and timing of shunt malfunction are well documented. Although the shunt design trials have been negative to date, valves have important effects that have not as yet been translated to improved outcome.

Spontaneous intraparenchymal hemorrhage in full-term neonates.

OBJECTIVE: Spontaneous intraparenchymal hemorrhage is extremely rare in full-term newborns. Reports to date have been limited to descriptions of individual cases, small groups within larger studies of intracranial hemorrhage, and one series of four patients. Structural lesions are rarely identified, and the majority of patients described have been managed without surgical intervention. METHODS: Analysis of a computerized database of pediatric neurosurgical patients from January 1960 to February 2000 identified full-term newborns younger than 3 months of age with nontraumatic intraparenchymal hemorrhages. Prenatal histories, labor and delivery histories, clinical presentations, imaging studies, management, and outcomes were reviewed. RESULTS: Eleven full-term newborns with spontaneous intraparenchymal hemorrhages were identified. The majority had normal prenatal courses. Most presented within the first 2 days of life (6 of 11 patients), and the most common presenting sign was seizure (7 of 11 patients). No cause was identified in 6 of 11 patients; the remainder were attributed to coagulopathy (n = 3), ruptured intracranial aneurysm (n = 1), or hemorrhagic infarction (n = 1). Eight patients underwent surgical hematoma evacuation on the basis of radiographic evidence of significant mass effect, evidence of signs of elevated intracranial pressure, or both. Three patients did not receive surgical intervention. There were no subsequent hemorrhages or deaths during a mean follow-up period of 4.5 years (range, 1-16 yr). Four patients had normal neurological outcomes, four had motor deficits (one of whom additionally demonstrated cognitive delay), and three had delayed speech. CONCLUSION: No cause is identified in most newborns with spontaneous intraparenchymal hemorrhage. Radiographic evidence of mass effect or signs of elevated intracranial pressure may necessitate surgical hematoma evacuation. Outcome varies widely and may be normal, even in patients with sizeable intraparenchymal hemorrhages.

Cerebrospinal fluid shunt infection: a prospective study of risk factors.

OBJECT: Hydrocephalus is a common condition of childhood that usually requires insertion of a cerebrospinal fluid (CSF) shunt. Infection is one of the most devastating complications that may arise from the presence of CSF shunts. In this study, the authors prospectively analyzed perioperative risk factors for CSF shunt infection in a cohort of children. METHODS: Between 1996 and 1999, 299 eligible patients underwent CSF shunt operations (insertions and revisions) that were observed by a research nurse at a tertiary care pediatric hospital. Several perioperative variables were recorded. All cases were followed postoperatively for 6 months to note any development of CSF shunt infection. A Cox proportional hazards model was used to analyze the relationship between the variables and the development of shunt infection. Thirty-one patients (10.4%) experienced shunt infection. Three perioperative variables were significantly associated with an increased risk of shunt infection: 1) the presence of a postoperative CSF leak (hazard ratio [HR] 19.16, 95% confidence interval [CI] 6.96-52.91); 2) patient prematurity (< 40 weeks' gestation at the time of shunt surgery: HR 4.72, 95% CI 1.71-13.06), and 3) the number of times the shunt system was inadvertently exposed to breached surgical gloves (HR 1.07, 95% CI 1.02-1.12). CONCLUSIONS: Three variables associated with an increased incidence of shunt infection have been identified. Changes in clinical practice should address these variables, as follows. 1) Great care should be taken intraoperatively to avoid a postoperative CSF leak. 2) Alternatives to placement of a CSF shunt in premature infants should be studied. 3) Surgeons should minimize manual contact with the shunt system and consider the use of double gloves.

Predicting shunt failure on the basis of clinical symptoms and signs in children.

OBJECT: In evaluating pediatric patients for shunt malfunction, predictive values for symptoms and signs are important in deciding which patients should undergo an imaging study, whereas determining clinical findings that correlate with a low probability of shunt failure could simplify management. METHODS: Data obtained during the recently completed Pediatric Shunt Design Trial (PSDT) were analyzed. Predictive values were calculated for symptoms and signs of shunt failure. To refine predictive capability, a shunt score based on a cluster of signs and symptoms was derived and validated using multivariate methods. Four hundred thirty-one patient encounters after recent shunt insertions were analyzed. For encounters that took place within 5 months after shunt insertion (early encounters), predictive values for symptoms and signs included the following: nausea and vomiting (positive predictive value [PPV] 79%, likelihood ratio [LR] 10.4), irritability (PPV 78%, LR 9.8), decreased level of consciousness (LOC) (PPV 100%), erythema (PPV 100%), and bulging fontanelle (PPV 92%, LR 33.1). Between 9 months and 2 years after shunt insertion (late encounters), only loss of developmental milestones (PPV 83%, LR 36.7) and decreased LOC (PPV 100%) were strongly associated with shunt failure. However, the absence of a symptom or sign still left a 15 to 29% (early encounter group) or 9 to 13% (late encounter group) chance of shunt failure. Using the shunt score developed for early encounters, which sums from 1 to 3 points according to the specific symptoms or signs present, patients with scores of 0, 1, 2, and 3 or greater had shunt failure rates of 4%, 50%, 75%, and 100%, respectively. Using the shunt score derived from late encounters, patients with scores of 0, 1, and 2 or greater had shunt failure rates of 8%, 38%, and 100%, respectively. CONCLUSIONS: In children, certain symptoms and signs that occur during the first several months following shunt insertion are strongly associated with shunt failure; however, the individual absence of these symptoms and signs offers the clinician only a limited ability to rule out a shunt malfunction. Combining them in a weighted scoring system improves the ability to predict shunt failure based on clinical findings.