Medial-lateral centre of mass displacement and base of support are equally good predictors of metabolic cost in amputee walking.

Amputees are known to walk with greater metabolic cost than able-bodied individuals and establishing predictors of metabolic cost from kinematic measures, such as centre of mass (CoM) motion, during walking are important from a rehabilitative perspective, as they can provide quantifiable measures to target during gait rehabilitation in amputees. While it is known that vertical CoM motion poorly predicts metabolic cost, CoM motion in the medial-lateral (ML) and anterior-posterior directions have not been investigated in the context of gait efficiency in the amputee population. Therefore, the aims of this study were to investigate the relationship between CoM motion in all three directions of motion, base of support and walking speed, and the metabolic cost of walking in both able-bodied individuals and different levels of lower limb amputee. 37 individuals were recruited to form groups of controls, unilateral above- and below-knee, and bilateral above-knee amputees respectively. Full-body optical motion and oxygen consumption data were collected during walking at a self-selected speed. CoM position was taken as the mass-weighted average of all body segments and compared to each individual's net non-dimensional metabolic cost. Base of support and ML CoM displacement were the strongest correlates to metabolic cost and the positive correlations suggest increased ML CoM displacement or Base of support will reduce walking efficiency. Rehabilitation protocols which indirectly reduce these indicators, rather than vertical CoM displacement will likely show improvements in amputee walking efficiency.

Energy flow analysis of amputee walking shows a proximally-directed transfer of energy in intact limbs, compared to a distally-directed transfer in prosthetic limbs at push-off.

Reduced capacity and increased metabolic cost of walking occurs in amputees, despite advances in prosthetic componentry. Joint powers can quantify deficiencies in prosthetic gait, but do not reveal how energy is exchanged between limb segments. This study aimed to quantify these energy exchanges during amputee walking. Optical motion and forceplate data collected during walking at a self-selected speed for cohorts of 10 controls, 10 unilateral trans-tibial, 10 unilateral trans-femoral and 10 bilateral trans-femoral amputees were used to determine the energy exchanges between lower limb segments. At push-off, consistent thigh and shank segment powers were observed between amputee groups (1.12W/kg vs. 1.05W/kg for intact limbs and 0.97W/kg vs. 0.99W/kg for prosthetic limbs), and reduced prosthetic ankle power, particularly in trans-femoral amputees (3.12W/kg vs. 0.87W/kg). Proximally-directed energy exchange was observed in the intact limbs of amputees and controls, while prosthetic limbs displayed distally-directed energy exchanges at the knee and hip. This study used energy flow analysis to show a reversal in the direction in which energy is exchanged between prosthetic limb segments at push-off. This reversal was required to provide sufficient energy to propel the limb segments and is likely a direct result of the lack of push-off power at the prosthetic ankle, particularly in trans-femoral amputees, and leads to their increased metabolic cost of walking.

Resolution of low-grade proteinuria is associated with improved outcomes after renal transplantation-a retrospective longitudinal study.

Low-grade proteinuria and systolic hypertension (SHT) are risk factors for allograft failure. Both are dynamic variables and their relationship is not independent. We have simultaneously analyzed the effects of proteinuria and SHT on graft outcomes in 805 adult Kidney Transplant Recipients and impact of their changes over time. Proteinuria and systolic blood pressure (SBP) were recorded for years 1 and 3 posttransplantation. Subjects with proteinuria >1 g/day were excluded. Patients were divided into groups based on proteinuria (Absent(A) <150 mg/day or low-grade(P)150 mg-1 g/day) and blood pressure (Normotensive-SBP <140 mmHg or hypertensive-SBP ≥ 140 mmHg). Graft survival was assessed in all four groups over 10 years by multivariate analysis. At the three annual time points (Year 1, 2 and 3) hypertensive patients with proteinuria had the worst graft survival. Patients with persistent proteinuria between years 1-2 and 2-3 had the poorest graft survival with an improvement if proteinuria regressed (P-A), especially in the Hypertensive group. The impact of proteinuria was highest in persistently hypertensive patients between years 1-3. Thus both proteinuria and SHT were associated with poor graft survival and the combination of the two led to the worst outcomes. Importantly, SHT was associated with significantly worse outcomes in patients with proteinuria. Patient cohort with SHT and low-grade proteinuria represent a selective group that might benefit from intervention.

Reconstruction of perineal defects.

INTRODUCTION: Perineal defects are commonly encountered in an oncological setting although they may also present as a result of trauma and infection (eg following Fournier's gangrene). Reconstruction of these poses functional as well as aesthetic challenges. Skin coverage and tissue volume may both be required in addition to anogenital preservation or reconstruction. General prerequisites of an adequate reconstruction of perineal defects include provision of skin cover, well vascularised tissue to fill the dead space (reducing fluid collection and infection), vulvovaginal reconstruction and no faecal or urinary contamination. METHODS: A literature search was performed using PubMed and MEDLINE ® . The search terms included 'perineal defects', 'perineal reconstruction', 'perforator flaps for perineum', 'vulval flaps', 'secondary healing of wound' and 'vacuum assisted closure'. Backward chaining of reference lists from retrieved papers was also used to expand the search. FINDINGS: Modern developments have led to an increased expectation in improved quality of life as the main goal of reconstruction, therefore necessitating surgery with less morbidity and early return to normal activity. Progress in microsurgical procedures has been the main recent advance in perineal reconstruction and, in future, refinements in perforator flap design and tissue engineering techniques will lead to even better reconstructions.

Enhanced differentiation of osteoclasts from mononuclear precursors in patients with Gaucher disease.

Gaucher disease (GD) is an autosomal recessive disorder caused by deficiency of ß-glucocerebrosidase. Storage of glucosylceramide in reticuloendothelial cells results in multiorgan pathology including bone disease. Established skeletal disease may remain problematic despite Gaucher-specific treatment. Both osteopenia and osteonecrosis have been described but the underlying pathophysiology, in particular the role of monocyte-derived osteoclasts is not well defined. The objective of this study was to explore the effect of glucocerebrosidase deficiency, inhibition and replacement on osteoclast development and function. In cultures derived from GD patients, or where GBA was chemically inhibited multinucleate giant cells expressing markers of osteoclast differentiation occurred earlier and in greater numbers compared to normal controls and the functional capacity of osteoclasts for bone resorption was enhanced. Increases in osteoclast number and activity correlated with radiological markers of active bone disease. Abnormalities were reversed by addition of specific therapies and were attenuated by co-culture with cells derived from healthy controls (HCs). Numbers of osteoblast lineage cells in the peripheral blood were mismatched to osteoclast precursors indicating uncoupling of osteoblast-osteoclast regulation which may further impact on bone remodelling. Elucidation of the underlying mechanisms of these changes will suggest rational therapies for the most disabling aspect of this condition.

An analysis of lymphocyte phenotype after steroid avoidance with either alemtuzumab or basiliximab induction in renal transplantation.

Several studies have analyzed the phenotype of repopulated T-lymphocytes following alemtuzumab induction; however there has been less scrutiny of the reconstituted B-cell compartment. In the context of a randomized controlled trial (RCT) comparing alemtuzumab induction with tacrolimus monotherapy against basiliximab induction with tacrolimus and mycophenolate mofetil (MMF) therapy in renal transplantation, we analyzed the peripheral B- and T-lymphocyte phenotypes of patients at a mean of 25 +/- 2 months after transplantation. We examined the relationship between peripheral lymphocyte phenotype and graft function. Patients who received alemtuzumab had significantly higher numbers of B cells including naïve, transitional and regulatory subsets. In contrast, the CD4(+) T-cell compartment was dominated by a memory cell phenotype. Following either basiliximab or alemtuzumab induction patients with lower numbers of B cells or B subsets had significantly worse graft function. For alemtuzumab there was also a correlation between these subsets the stability of graft function and the presence of HLA-specific antibodies. These results demonstrate that a significant expansion of regulatory type B cells is associated with superior graft function and that this pattern is more common after alemtuzumab induction. This phenomenon requires further prospective study to see whether this phenotype could be used to customize immunotherapy.

Impact of age matching of donors to recipients on renal transplant outcomes following donation after cardiac death.

Organ donation after cardiac death (DCD) provides a valuable supply of grafts for renal transplantation. Age matching of donors to recipients is often used. We sought to determine the impact of age matching on the outcomes among our cohort of DCD renal transplant recipients. Using our institutional database, we gathered information on all DCD renal transplants performed between April 2002 and December 2009. We divided the cohort into two groups based upon the donor:recipient age ratio: age-matched (between 25th and 75th percentiles, n = 99) and non-age-matched (<25th percentile and >75th centile, n = 100). We failed to demonstrate any significant difference between the two groups in terms of early complications or long-term outcome or function. Age matching did not appear to affect graft outcomes, particularly for young donors, but may have a role in older donors.

Pathology and viral antigen distribution of lethal pneumonia in domestic cats due to pandemic (H1N1) 2009 influenza A virus.

A novel swine-origin H1N1 influenza A virus has been identified as the cause of the 2009 influenza pandemic in humans. Since then, infections with the pandemic (H1N1) 2009 influenza virus have been documented in a number of animal species. The first known cases of lethal respiratory disease associated with pandemic (H1N1) 2009 influenza virus infection in house pets occurred in domestic cats in Oregon. A 10-year-old neutered domestic shorthair and an 8-year-old spayed domestic shorthair died shortly after developing severe respiratory disease. Grossly, lung lobes of both cats were diffusely firm and incompletely collapsed. Histologically, moderate to severe necrotizing to pyonecrotizing bronchointerstitial pneumonia was accompanied by serofibrinous exudation and hyaline membranes in the alveolar spaces. Influenza A virus was isolated from nasal secretions of the male cat and from lung homogenate of the female cat. Both isolates were confirmed as pandemic (H1N1) 2009 influenza virus by real-time reverse transcriptase polymerase chain reaction. With immunohistochemistry, influenza A viral antigen was demonstrated in bronchiolar epithelial cells, pneumocytes, and alveolar macrophages in pneumonic areas. The most likely sources of infection were people in the household with influenza-like illness or confirmed pandemic (H1N1) 2009 influenza. The 2 cases reported here provide, to the best of the authors' knowledge, the first description of the pathology and viral antigen distribution of lethal respiratory disease in domestic cats after natural pandemic (H1N1) 2009 influenza virus infection, probably transmitted from humans.

Minimal-change nephrotic syndrome due to occupational mercury vapor inhalation.

A 25-year-old man developed nephrotic syndrome and severe hypertension following occupational exposure to mercury vapor whilst working at a fluorescent light factory. A renal biopsy confirmed minimal-change disease on light microscopy, immunofluorescence and electron microscopy. He was also noted to be polycythemic which was initially treated with venesection. His blood and urinary mercury levels were elevated and so he was given chelation therapy with 2,3-dimercaptopropane-1-sulfonate (DMPS), along with steroids for his minimal-change disease, resulting in full resolution of his nephrotic syndrome within 6 weeks. He remains well with normal renal function, blood pressure and normal blood and urine mercury concentrations.

Patterns of chromosomal evolution in Sigmodon, evidence from whole chromosome paints.

Of the superfamily Muroidea (31 genera, 1578 species), the Sigmodontinae (74 genera, 377 species) is the second largest subfamily in number of species and represents a significant radiation of rodent biodiversity. Only 2 of the 74 genera are found in both North and South America (Sigmodon and Oryzomys) and the remainder are exclusively from South America. In recent molecular studies, the genus Sigmodon (Cricetidae, Sigmodontinae) has been considered sister to many other South American Sigmodontines [Steppan et al., 2004]. We examine the chromosomal evolution of 9 species of Sigmodon utilizing chromosomal paints isolated from S. hispidus, proposed to be similar to the ancestral karyotype [Elder, 1980]. Utilizing a phylogenetic hypothesis of a molecular phylogeny of Sigmodon [Henson and Bradley, 2009], we mapped shared chromosomal rearrangements of taxa on a molecular tree to estimate the evolutionary position of each rearrangement. For several species (S. hirsutus, S. leucotis, S. ochrognathus, S. peruanus, and S. toltecus), the karyotype accumulated few or no changes, but in three species (S. arizonae, S. fulviventer, and S. mascotensis) numerous karyotype rearrangements were observed. These rearrangements involved heterochromatic additions, centric fusions, tandem fusions, pericentric inversions, as well as the addition of interstitial DNA not identified by chromosome paints or C-banding. The hypothesis that the ancestral karyotype for this complex had a diploid number of 52, a fundamental number of 52, and a G-band pattern of which most, if not all are similar to that present in modern day S. hispidus fails to be rejected. This hypothesis remains viable as an explanation of chromosomal evolution in Sigmodontine rodents.

Characterization of a novel alphaherpesvirus associated with fatal infections of domestic rabbits.

A virus was found to be associated with a severe disease affecting rabbits on a farm near Anchorage, Alaska. Extracts from the skin of infected rabbits produced syncytia and cell lysis in cultured rabbit skin, rabbit kidney, and Vero cells. Examination of the infectious agent by electron microscopy revealed an icosahedral nucleocapsid surrounded by an envelope with a diameter of about 120 nm, suggesting that it was a herpesvirus. The viral genome was determined to be composed of double-stranded DNA of 120-130 kbp. PCR using degenerate primers to conserved herpesvirus genes was used to amplify sequences from purified viral DNA. Sequencing of these products allowed the design of specific primers so that complete sequence data for a number of genes could be determined. Analysis of these data indicated that the virus is most closely related to bovine herpesvirus 2. The next most closely related viruses are human herpesviruses 1 and 2, and a number of cercopithecine herpesviruses. Experimental exposure of domestic rabbits to the isolate resulted in severe clinical disease and necrosis in the spleen and lymph node. In addition, viral DNA was identified in a variety of tissues by PCR, consistent with a systemic infection. Taken together, these data suggest that this virus is highly pathogenic for domestic rabbits and belongs to the family Herpesviridae, subfamily Alphaherpesvirinae, genus Simplexvirus.

An outbreak of fatal herpesvirus infection in domestic rabbits in Alaska.

A herpesvirus infection affecting mini Rex and crossbred meat rabbits was identified in a rabbitry in Alaska. Illness affected over half of the 55 rabbits on the premises, and 16 rabbits died or were euthanatized because of illness. Disease affected all ages from adults to nursing young and occurred over an approximately 2-month period. Clinical signs included conjunctivitis and periocular swelling, ulcerative dermatitis, progressive weakness, anorexia, respiratory distress, and abortion. Hemorrhagic dermatitis and panniculitis were associated with epidermal microvesicular degeneration, dermal and subcutaneous vascular necrosis, and thrombosis. Eosinophilic intranuclear inclusions consistent with herpesvirus were found within the epidermis and superficial follicular epithelium and within mesenchymal cells within the dermis and subcutis. Syncytial cells containing viral inclusions occurred within the epidermal and superficial follicular epithelium. Other findings were hemorrhagic necrosis of the myocardium with rare intranuclear inclusions within stromal cells, multifocal pulmonary hemorrhage, hemorrhage with sinus erythrophagocytosis in lymph nodes, and massive necrosis and fibrin deposition within red pulp of the spleen. A virus isolated from the skin produced syncytia, intranuclear inclusions, and cell lysis typical of herpesvirus in rabbit kidney cells in vitro. The viral isolate was characterized ultrastructurally as an enveloped virus with icosahedral nucleocapsids 100 nm diameter, consistent with a herpesvirus.

Impact of Single pMOSFET Dielectric Degradation on NAND Circuit Performance.

Degradation of CMOS NAND logic circuits resulting from dielectric degradation of a single pMOSFET using constant voltage stress has been examined by means of a switch matrix technique. As a result, the NAND gate rise time increases by greater than 65%, which may lead to timing errors in high frequency digital circuits. In addition, the NAND gate DC switching point voltage shifts by nearly 11% which may be of consequence for analog or mixed signal applications. Experimental results for the degraded pMOSFET reveal a decrease in drive current by approximately 43%. There is also an increase in threshold voltage by 23%, a decrease in source to drain conductance of 30%, and an increase in channel resistance of about 44%. A linear relationship between the degradation of the pMOSFET channel resistance and the increase in NAND gate rise time is demonstrated, thereby providing experimental evidence of the impact of a single degraded pMOSFET on NAND circuit performance.

Analysis of the genome sequence of an alpaca coronavirus.

Coronaviral infection of New World camelids was first identified in 1998 in llamas and alpacas with severe diarrhea. In order to understand this infection, one of the coronavirus isolates was sequenced and analyzed. It has a genome of 31,076 nt including the poly A tail at the 3' end. This virus designated as ACoV-00-1381 (ACoV) encodes all 10 open reading frames (ORFs) characteristic of Group 2 bovine coronavirus (BCoV). Phylogenetic analysis showed that the ACoV genome is clustered closely (>99.5% identity) with two BCoV strains, ENT and LUN, and was also closely related to other BCoV strains (Mebus, Quebec, DB2), a human corona virus (strain 043) (>96%), and porcine hemagglutinating encephalomyelitis virus (>93% identity). A total of 145 point mutations and one nucleotide deletion were found relative to the BCoV ENT. Most of the ORFs were highly conserved; however, the predicted spike protein (S) has 9 and 12 amino acid differences from BCoV LUN and ENT, respectively, and shows a higher relative number of changes than the other proteins. Phylogenetic analysis suggests that ACoV shares the same ancestor as BCoV ENT and LUN.

Comparative phylogeography of short-tailed bats (Carollia: Phyllostomidae).

This is the first study of comparative phylogeography involving closely related species of Neotropical bats of the family Phyllostomidae. We compared patterns of geographical variation within the five species of fruit-eating bats currently recognized in the genus Carollia using the complete mitochondrial cytochrome-b gene. Our results suggest that the combined effect of the uplift of the Andes and the Panamanian land bridge has been as important for bats as for terrestrial mammals in shaping present-day biodiversity in the New World tropics. Species in this genus can be arranged in two highly supported clades, with a deep subdivision within each that corresponds well to differences across the Andes. We found three congruent phylogeographical patterns across species in this genus. First, the closer relationship between samples from western Ecuador and those from Central America, compared with populations east of the Andes in C. brevicauda, C. castanea and C. perspicillata. Second, the likelihood of a similar timing in South America for the arrival and diversification of C. brevicauda and C. perspicillata from their Central America ancestors. Third, the expansion of C. perspicillata and C. sowelli into northwestern Central America in the relatively recent past. Using a molecular clock, with rates ranging from 2.3 to 5% per 10(6) years, diversification within Carollia would have occurred over the last 1-4.5 Myr. These estimates agree well with the last rise of the Northern Andes and the Panama isthmus.

The use of nuclear and mitochondrial single nucleotide polymorphisms to identify cryptic species.

There is growing interest in the use of single nucleotide polymorphisms for evolutionary and population genetics. We tested the efficacy of one of the available single nucleotide polymorphism techniques, single-base extension, in distinguishing four cryptic species of Microtus. Sequence data were available for these species at nuclear and mitochondrial loci and their identity could be independently confirmed using karyotypes. We found that the development and optimization of single nucleotide polymorphisms required extensive effort, and that the method accurately identified the correct nucleotide at single nucleotide polymorphism sites approximately 90% of the time at the conserved nuclear locus. Correct identification rates were much lower at the highly variable mitochondrial locus.

Walking speed in children and young adults with neuromuscular disease: comparison between two assessment methods.

Self-selected walking speed is being increasingly used as a primary outcome measure in the management of neuromuscular disease. It would be useful if the speed recorded in the gait laboratory represented the child's walking speed in the community. This study investigated the difference in self-selected walking speeds between a 10-meter walk, as measured during instrumented gait analysis, and a 10-minute walk. The authors found that self-selected walking speed during the 10-minute walk was slower than the self-selected walking speed recorded during the 10-meter walk. The former may be more representative of walking speed in the community setting. Walking speed measured during walks of 10 minutes or more should become an integral part of gait laboratory evaluation.

Distribution of LINEs and other repetitive elements in the karyotype of the bat Carollia: implications for X-chromosome inactivation.

The Lyon repeat hypothesis postulates that long interspersed elements (LINEs) play a role in X-chromosome inactivation. Evidence to support this hypothesis includes the observation that the degree of inactivation of autosomes translocated to the X chromosome is correlated with LINE density on that autosome. We examined the distribution of LINEs in the fruit bat Carollia brevicauda, which has an autosomal translocation to the X that occurred at least 7 million years ago. A quantitative analysis of LINE accumulation on multiple metaphase chromosome spreads revealed a significant accumulation on the original X relative to the attached autosome, the homolog of that autosome (Y(2)), and chromosome 1. Previous replication studies indicate that for the X and attached autosome, only the original X chromosome replicates late in Carollia females, and that the attached autosome replicates in the same timeframe as other autosomes. These data are compatible with the Lyon repeat hypothesis, and the possibility that LINEs act as booster elements for X inactivation remains a viable hypothesis. We address the procedures and limitations of quantitative analysis based on in situ hybridization.

Distribution and characterization of microsatellites in the emu (Dromaius novaehollandiae) genome.

This study generates data concerning the genome of a flightless species of bird, the emu. We examined and ultimately rejected the following hypotheses: (1) Microsatellites are randomly distributed throughout the emu genome. (2) The relative order of abundance of dinucleotides will be constant across genomes. (3) Interspersion distances for a given dinucleotide will be equal across vertebrate genomes. (4) In all genomes, a dinucleotide will be more frequent than any trinucleotide. (5) The percentage of single-copy DNA will remain the same in emus as in other volant birds. A cosmid library representing 4.48% of the emu genome was probed with 23 microsatellites. Hybridizations were scored on a scale of 0-3. The average insert size, approximately 40 kb, was used to determine frequency and interspersion. The cosmid library was probed with genomic DNA to determine the percent single copy. Co-occurrence frequencies and confidence intervals were compared to expected using chi-squared. The genome is estimated to contain a microsatellite repeat every 48 kb. Of 1632 clones probed for single-copy DNA, 643 displayed maximal hybridization, 220 displayed moderate hybridization, and 202 had minimal hybridization. After 3 days, 567 showed no hybridization.

The effect of gadolinium-based MRI contrast agents on the biodistribution of (67)Ga.

It has been reported that administration of the paramagnetic contrast agent Gd-diethylenetriaminepentaacetic acid (Gd-DTPA, gadopentate) prior to 67Ga citrate could lead to poor quality scans, characterized by pronounced bone uptake and a loss of tumour avidity. Suggestions to account for this behaviour included in vivo dissociation or the presence of free DTPA in the formulation. The objective of this study was to assess this potential interference in 67Ga imaging using a mouse model. Commercial gadopentate and gadodiamide contrast agents at doses up to 5mmol*kg(-1) were injected into mature female Balb/c mice 4h before i.v. 67Ga citrate, then the biodistribution was determined at 24h. Gd-DTPA solutions containing excess Gd or DTPA were examined as well. The model was verified by identical studies using inactive Ga(III) or Fe(III) at 0.1mmol*kg(-1). The effects of Gd(III) or the DTPA ligand at this dose were also determined. Administration of Gd-DTPA was found to produce no marked changes in 67Ga biodistribution. Minor changes occurred after 0.1mmol*kg(-1) Gd(III) or the DTPA ligand, but could not account for the scan changes reported above. Inactive Ga(III) or Fe(III), as expected, caused a marked reduction of 67Ga uptake in all tissues except bone, leading to greatly increased total bone:total soft tissue ratios. It is concluded that Gd-DTPA or its constituents do not significantly alter the biodistribution of 67Ga citrate in mice. Extrapolating these findings to the human situation suggests that the previously reported scan changes may have been the result of other undetermined factors.