Podocyte protease activated receptor 1 stimulation in mice produces focal segmental glomerulosclerosis mirroring human disease signaling events.

About 30% of patients who have a kidney transplant with underlying nephrotic syndrome (NS) experience rapid relapse of disease in their new graft. This is speculated to be due to a host-derived circulating factor acting on podocytes, the target cells in the kidney, leading to focal segmental glomerulosclerosis (FSGS). Our previous work suggests that podocyte membrane protease receptor 1 (PAR-1) is activated by a circulating factor in relapsing FSGS. Here, the role of PAR-1 was studied in human podocytes in vitro, and using a mouse model with developmental or inducible expression of podocyte-specific constitutively active PAR-1, and using biopsies from patients with nephrotic syndrome. In vitro podocyte PAR-1 activation caused a pro-migratory phenotype with phosphorylation of the kinase JNK, VASP protein and docking protein Paxillin. This signaling was mirrored in podocytes exposed to patient relapse-derived NS plasma and in patient disease biopsies. Both developmental and inducible activation of transgenic PAR-1 (NPHS2 Cre PAR-1Active+/-) caused early severe nephrotic syndrome, FSGS, kidney failure and, in the developmental model, premature death. We found that the non-selective cation channel protein TRPC6 could be a key modulator of PAR-1 signaling and TRPC6 knockout in our mouse model significantly improved proteinuria and extended lifespan. Thus, our work implicates podocyte PAR-1 activation as a key initiator of human NS circulating factor and that the PAR-1 signaling effects were partly modulated through TRPC6.

Building Public Health Surveillance 3.0: Emerging Timely Measures of Physical, Economic, and Social Environmental Conditions Affecting Health.

In response to rapidly changing societal conditions stemming from the COVID-19 pandemic, we summarize data sources with potential to produce timely and spatially granular measures of physical, economic, and social conditions relevant to public health surveillance, and we briefly describe emerging analytic methods to improve small-area estimation. To inform this article, we reviewed published systematic review articles set in the United States from 2015 to 2020 and conducted unstructured interviews with senior content experts in public heath practice, academia, and industry. We identified a modest number of data sources with high potential for generating timely and spatially granular measures of physical, economic, and social determinants of health. We also summarized modeling and machine-learning techniques useful to support development of time-sensitive surveillance measures that may be critical for responding to future major events such as the COVID-19 pandemic. (Am J Public Health. 2022;112(10):1436-1445. https://doi.org/10.2105/AJPH.2022.306917).

Transportal central femoral tunnel placement has a significantly higher revision rate than transtibial AM femoral tunnel placement in hamstring ACL reconstruction.

PURPOSE: It is proposed that central femoral ACL graft placement better controls rotational stability. This study evaluates the consequence of changing the femoral tunnel position from the AM position drilled transtibially to the central position drilled transportally. The difference in ACL graft failure is reported. METHODS: This prospective consecutive patient single surgeon study compares the revision rates of 1016 transtibial hamstring ACL reconstructions followed for 6-15 years with 464 transportal hamstring ACL reconstructions followed for 2-6 years. Sex, age, graft size, time to surgery, meniscal repair and meniscectomy data were evaluated as contributing factors for ACL graft failure to enable a multivariate analysis. To adjust for the variable follow-up a multivariate hazard ratio, failure per 100 graft years and Kaplan-Meier survivorship was determined. RESULTS: With transtibial ACLR 52/1016 failed (5.1%). With transportal ACLR 32/464 failed (6.9%). Significant differences between transportal and transtibial ACLR were seen for graft diameter, time to surgery, medial meniscal repair rates and meniscal tissue remaining after meniscectomy. Adjusting for these the multivariate hazard ratio was 2.3 times higher in the transportal group (p = 0.001). Central tunnel placement resulted in a significantly 3.5 times higher revision rate compared to an anteromedial tunnel placement per 100 graft years (p = 0.001). Five year survival was 980/1016 (96.5%) for transtibial versus 119/131 (90.5%) for transportal. Transportal ACLR also showed a significantly higher earlier failure rate with 20/32 (61%) of the transportal failing in the first year compared with 14/52 (27%) for transtibial. (p = 0.001.) CONCLUSION: Transportal central femoral tunnel ACLR has a higher failure rate and earlier failure than transtibial AM femoral tunnel ACLR. LEVEL OF EVIDENCE: Level II-prospective comparative study.

High Bragg reflectivity of diamond crystals exposed to multi-kW†mm-2 X-ray beams.

X-ray free-electron lasers in the oscillator configuration (XFELO) are future fully coherent hard X-rays sources with ultrahigh spectral purity. X-ray beams circulate in an XFELO optical cavity comprising diamond single crystals. They function as high-reflectance (close to 100%), narrowband (∼10 meV) Bragg backscattering mirrors. The average power density of the X-ray beams in the XFELO cavity is predicted to be as high as ∼10 kW mm-2. Therefore, XFELO feasibility relies on the ability of diamond crystals to withstand such a high radiation load and preserve their high reflectivity. Here the endurance of diamond crystals to irradiation with multi-kW mm-2 power density X-ray beams is studied. It is shown that the high Bragg reflectivity of the diamond crystals is preserved after the irradiation, provided it is performed at ∼1 × 10-8 Torr high-vacuum conditions. Irradiation under 4 × 10-6 Torr results in a ∼1 meV shift of the Bragg peak, which corresponds to a relative lattice distortion of 4 × 10-8, while the high Bragg reflectivity stays intact.

Regional Intraosseous Administration of Prophylactic Antibiotics is More Effective Than Systemic Administration in a Mouse Model of TKA.

BACKGROUND: In human TKA studies, intraosseous regional administration (IORA) of prophylactic antibiotics achieves local tissue antibiotic concentrations 10 times greater than systemic administration. However, it is unclear if such high concentrations provide more effective prophylaxis. QUESTIONS/PURPOSES: We asked: (1) What prophylaxis dosage and route (intravenous [IV] versus IORA of prophylactic antibiotics) produce less in vivo bacterial burden compared with no-antibiotic controls? (2) Compared with controls, what prophylaxis dosage and route yield fewer colony-forming units (CFUs) in euthanized animals in a model of TKA? (3) Is prophylactic IORA of antibiotics more effective than same-dose IV antibiotic administration in reducing CFUs? METHODS: Mice (six to nine per group) were block randomized to one of six prophylaxis regimens: control, systemic cefazolin (C100IV), IORA of cefazolin (C100IORA), systemic vancomycin (V110IV), low-dose systemic vancomycin (V25IV), and low-dose IORA of vancomycin (V25IORA). Surgery involved placement of an intraarticular knee prosthesis, followed by an inoculum of bioluminescent Staphylococcus aureus strain Xen36. Biophotonic imaging assessed in vivo bacterial loads, and after 4 days bacterial load was quantified using culture-based techniques. Comparisons were made for each prophylactic regimen to controls and between same-dose IV and IORA of prophylactic antibiotic regimens. RESULTS: Mice treated with systemic high-dose vancomycin, IORA of vancomycin, or IORA of cefazolin had lower in vivo Staphylococcus aureus burdens (median area under curve, Control: 5.0 × 10(6); V110IV: 1.5 × 10(6), difference of medians 3.5 × 10(6), p = 0.003; V25IV: 1.94 × 10(6), difference 3.07 × 10(6), p = 0.49; V25IORA: 1.51 × 10(6), difference 3.5 × 10(6), p = 0.0011; C100IORA: 1.55 × 10(6), difference 3.46 × 10(6), p = 0.0016; C100IV: 2.35 × 10(6), difference 2.66 × 10(6), p = 0.23.) Similar findings were seen with culture-based techniques on recovered implants. IORA of prophylactic antibiotics was more effective than same-dose IV administration in reducing bacterial load on recovered implants (median CFUs < 7.0 × 10(0) vs 2.83 × 10(2), p = 0.0183). CONCLUSIONS: IORA of prophylactic cefazolin and vancomycin was more effective than the same dose of antibiotic given systemically. The effectiveness of vancomycin in particular was enhanced by IORA of prophylactic antibiotics despite using a lower dose. CLINICAL RELEVANCE: Our study supports previous studies of IORA of prophylactic antibiotics in humans and suggests this novel form of administration has the potential to enhance the effectiveness of prophylaxis in TKA. Because of concerns regarding antibiotic stewardship, IORA of prophylactic vancomycin may be more appropriately restricted to patients having TKA who are at greater risk of infection, and clinical trials are in progress.

Femtosecond laser cataract surgery: challenging cases.

PURPOSE OF REVIEW: Emerging data in the peer-reviewed literature indicate that femtosecond laser-assisted cataract surgery (LCS) is a well tolerated and effective alternative to conventional phacoemulsification. Initial reports have largely been based on findings from an optimal patient selection. As confidence with the technology has grown, clinical indications have expanded and the benefit of LCS in high-risk patients with complex cataracts is increasingly being considered. RECENT FINDINGS: We discuss challenging cataract surgery cases, citing the currently available literature alongside experience from over 3000 completed LCS cases at our centre. SUMMARY: Current experience is limited. However, LCS platforms are continuously evolving and improving. The results collected to date would suggest that the precision and safety offered by LCS may improve outcomes in these challenging cases.

Development of a complex amino acid supplement, Fatigue Reviva™, for oral ingestion: initial evaluations of product concept and impact on symptoms of sub-health in a group of males.

BACKGROUND: A new dietary supplement, Fatigue Reviva™, has been recently developed to address issues related to amino acid depletion following illness or in conditions of sub-health where altered amino acid homeostasis has been associated with fatigue. Complex formulations of amino acids present significant challenges due to solubility and taste constraints. This initial study sets out to provide an initial appraisal of product palatability and to gather pilot evidence for efficacy. METHODS: Males reporting symptoms of sub-health were recruited on the basis of being free from any significant medical or psychological condition. Each participant took an amino acid based dietary supplement (Fatigue Reviva™) daily for 30 days. Comparisons were then made between pre- and post-supplement general health symptoms and urinary amino acid profiles. RESULTS: Seventeen men took part in the study. Following amino acid supplementation the total Chalder fatigue score improved significantly (mean ± SEM, 12.5 ± 0.9 versus 10.0 ± 1.0, P<0.03). When asked whether they thought that the supplement had improved their health, 65% of participants responded positively. A subgroup of participants reported gastrointestinal symptoms which were attributed to the supplement and which were believed to result from the component fructooligosaccharide. Analysis of urinary amino acids revealed significant alterations in the relative abundances of a number of amino acids after supplementation including an increase in valine, isoleucine and glutamic acid and reduced levels of glutamine and ornithine. Discriminant function analysis of the urinary amino acid data revealed significant differences between the pre- and post-supplement urine excretion profiles. CONCLUSIONS: The results indicated that Fatigue Reviva™ was palatable and that 65% of the study group reported that they felt the product had improved their health. The product could provide an effective tool for the management of unexplained fatigue and symptoms of sub-health. Further product development may yield additional options for those patients susceptible to fructooligosaccharide.

Significant Changes in Cytoplasmic Amino Acid Composition Occur in the Transition between Mid-Exponential and Stationary Phases of Growth of Staphylococcus aureus: An Example of Adaptive Homeostasis in Response to Nutrient Limitations.

The bacterial pathogen Staphylococcus aureus causes a wide range of infections that result in high morbidity and mortality rates worldwide. S. aureus is known for its capacity to survive harsh environments between hosts and certain strains are very efficient as opportunistic pathogens. It is important to understand their capacities for metabolic adaptation in response to changing environmental conditions. This investigation aimed to explore the alterations in the amino acid compositions of the cytoplasm as nutrients became limiting during the growth of S. aureus. Cells were grown under optimal growth conditions and harvested at the mid-exponential and stationary phases of growth and then extracted for the analyses of amino acids in the cytoplasm. The analyses revealed that the stationary phase cells had a significantly higher concentration of total cytoplasmic amino acids compared with cells at the mid-exponential phase and displayed substantial alterations in amino acid composition. Aspartic acid was the major amino acid in the stationary phase cells, whereas glutamic acid was the most abundant in the mid-exponential cells. The glutamic acid was reduced by 47% of its original value when the growth was extended to the stationary phase. Interestingly, certain amino acids were either absent or present depending on the phase of growth. These outcomes are in line with the premise that bacterial cells of S. aureus transition into a different form of metabolic homeostasis in the shift between the exponential and stationary phases of growth, as nutrients become depleted and waste products accumulate in the external medium. The ability of S. aureus to continually and promptly adapt to differences within growth phases may represent an essential strategy assisting its virulence as a successful opportunistic pathogen to establish infections. An understanding of the switch mechanisms controlling these obvious alterations in amino acids through the growth/life cycle of this virulent pathogen may provide novel clinical strategies to battle infection.

Cytoplasmic amino acid profiles of clinical and ATCC 29213 strains of Staphylococcus aureus harvested at different growth phases.

Staphylococcus aureus strains are a great contributor to both hospital acquired infections as well as community acquired infections. The objective of the present investigation was to compare potential differences in cytoplasmic amino acid levels between clinical and ATCC 29213 strains of S. aureus. The two strains were grown under ideal conditions to mid-exponential and stationary growth phases, after which they were harvested to analyze their amino acid profiles. Initially, the amino acid patterns of both strains were compared at the mid-exponential phase when grown in controlled conditions. At the mid-exponential phase, both strains shared common features in cytoplasmic amino acid levels, with glutamic acid, aspartic acid, proline, and alanine identified as key amino acids. However, the concentration profiles of seven amino acids exhibited major variances between the strains, even though the total cytoplasmic levels of amino acids did not alter significantly. At the stationary phase, the magnitudes of the amino acids abundant in the mid-exponential phase were altered. Aspartic acid became the most abundant amino acid in both strains accounting for 44% and 59% of the total amino acids in the clinical and ATCC 29213 strains, respectively. Lysine was the second most abundant amino acid in both strains, accounting for 16% of the total cytoplasmic amino acids, followed by glutamic acid, the concentration of which was significantly higher in the clinical strain than in the ATCC 29213 strain. Interestingly, histidine was clearly present in the clinical strain but was virtually lacking in the ATCC 29213 strain. This study reveals the dynamic diversity of amino acid levels among strains, which is an essential step toward illustrating the variability in S. aureus cytoplasmic amino acid profiles and could be significant in explaining variances among strains of S. aureus.

Changes in Amino Acid Metabolism of Staphylococcus aureus following Growth to the Stationary Phase under Adjusted Growth Conditions.

The sharp increase in infections due to Staphylococcus aureus is associated with its ability to adapt to changes in its habitat. This study aimed to investigate the differences in the cytoplasmic amino acid profiles of a clinical strain of S. aureus under five combinations of stress-induced conditions representative of a wound site by varying temperature 35-37 °C, adding 0-5% NaCl and adjusting pH 6-8. The results indicated that aspartic acid, lysine, glutamic acid and histidine were the most abundant cytoplasmic amino acids in the control samples grown under optimal growth conditions. However, the magnitudes and levels of these amino acids were altered under the various wound site conditions, which led to differential cytoplasmic amino acid profiles as characterized by multivariate analyses (PLS-DA). The total cytoplasmic amino acid content was significantly reduced in the cells grown with 2.5% NaCl added at pH 7 and 37 °C relative to the control samples and other growth regimes. However, all combinations of enhanced stress conditions showed unique and characteristic changes in the concentration profiles of the cytoplasmic amino acids. These outcomes supported the hypothesis that bacterial cells of S. aureus maintain different metabolic homeostasis under various stress-induced conditions. The potent capability of S. aureus to constantly and rapidly acclimatize to variations within the environment may reflect the crucial feature supporting its virulence as an opportunistic pathogenic bacterium to invade the wound site. Understanding the control systems governing these marked changes in amino acids during the adaptation to the potential wound site conditions of this dangerous bacterium may offer new clinical controls to combat infection.

Probiotics, their action modality and the use of multi-omics in metamorphosis of commensal microbiota into target-based probiotics.

This review article addresses the strategic formulation of human probiotics and allows the reader to walk along the journey that metamorphoses commensal microbiota into target-based probiotics. It recapitulates what are probiotics, their history, and the main mechanisms through which probiotics exert beneficial effects on the host. It articulates how a given probiotic preparation could not be all-encompassing and how each probiotic strain has its unique repertoire of functional genes. It answers what criteria should be met to formulate probiotics intended for human use, and why certain probiotics meet ill-fate in pre-clinical and clinical trials? It communicates the reasons that taint the reputation of probiotics and cause discord between the industry, medical and scientific communities. It revisits the notion of host-adapted strains carrying niche-specific genetic modifications. Lastly, this paper emphasizes the strategic development of target-based probiotics using host-adapted microbial isolates with known molecular effectors that would serve as better candidates for bioprophylactic and biotherapeutic interventions in disease-susceptible individuals.

Natural history of untreated syringomyelia in pediatric patients.

OBJECT: The natural history of syringomyelia in pediatric patients remains uncertain. Although symptomatic and operative cases of syringomyelia are well studied, there are fewer articles in the literature on the nonoperative syrinx and its clinical and radiological course. The purpose of this research was to analyze the natural history of untreated syringomyelia in pediatric patients presenting with minimal neurological symptoms. METHODS: A review of the neurosurgery database at British Columbia's Children's Hospital identified all pediatric patients (< 18 years of age) with syringes identified on MR imaging. Patients were included in this study if they had at least 2 MR images of the spine, at least 1 year apart, while receiving nonoperative treatment. Magnetic resonance imaging was used to determine changes in the size of the syrinx over time. Clinic notes were analyzed to establish demographic and clinical features and to determine any clinical changes over time. RESULTS: A total of 17 patients were included in the study. Symptoms at presentation were often mild and included limb numbness (3 cases), headaches (2 cases), mild sensory deficits (2 cases), mild motor deficits (3 cases), and intermittent incontinence (7 cases). The consultant neurosurgeon believed that the syrinx was not contributing to the symptoms in these 17 patients. The syrinx either remained unchanged (7 cases) or diminished in size (8 cases) in a total of 15 patients (88%). In the remaining 2 patients the authors noted an increase in syrinx size, in 1 of whom the clinical course also worsened. Both of these patients had a Chiari malformation and subsequently underwent craniocervical decompression. Overall, the mean change was -0.7 mm of maximal axial diameter (range -2.6 to +2.7 mm). Sixteen patients (94%) exhibited no worsening of symptoms over time. CONCLUSIONS: Syringomyelia often remains stable in patients receiving nonoperative treatment. However, given that 2 (12%) of 17 syringes in this series enlarged, it is likely appropriate to include periodic imaging in the follow-up of these cases.

Effect of chorioamnionitis on brain development and injury in premature newborns.

OBJECTIVE: The association of chorioamnionitis and noncystic white matter injury, a common brain injury in premature newborns, remains controversial. Our objectives were to determine the association of chorioamnionitis and postnatal risk factors with white matter injury, and the effects of chorioamnionitis on early brain development, using advanced magnetic resonance imaging. METHODS: Ninety-two preterm newborns (24-32 weeks gestation) were studied at a median age of 31.9 weeks and again at 40.3 weeks gestation. Histopathological chorioamnionitis and white matter injury were scored using validated systems. Measures of brain metabolism (N-acetylaspartate/choline and lactate/choline) on magnetic resonance spectroscopy, and microstructure (average diffusivity and fractional anisotropy) on diffusion tensor imaging were calculated from predefined brain regions. RESULTS: Thirty-one (34%) newborns were exposed to histopathological chorioamnionitis, and 26 (28%) had white matter injury. Histopathological chorioamnionitis was not associated with an increased risk of white matter injury (relative risk: 1.2; p = 0.6). Newborns with postnatal infections and hypotension requiring therapy were at higher risk of white matter injury (p < 0.03). Adjusting for gestational age at scan and regions of interest, histopathological chorioamnionitis did not significantly affect brain metabolic and microstructural development (p > 0.1). In contrast, white matter injury was associated with lower N-acetylaspartate/choline (-8.9%; p = 0.009) and lower white matter fractional anisotropy (-11.9%; p = 0.01). INTERPRETATION: Histopathological chorioamnionitis does not appear to be associated with an increased risk of white matter injury on magnetic resonance imaging or with abnormalities of brain development. In contrast, postnatal infections and hypotension are associated with an increased risk of white matter injury in the premature newborn.

Safety and efficacy of continuous morphine infusions following pediatric cranial surgery in a surgical ward setting.

PURPOSE: Morphine is avoided by many neurosurgeons following cranial surgery. There exists a concern regarding the potential complications and a perception that cranial surgery is less painful than other surgical procedures. At British Columbia Children's Hospital continuous morphine infusions (CMI) have been used to control pain in pediatric neurosurgical patients. The purpose of this study was to compare the safety and efficacy of continuous intravenous morphine infusion to standard oral analgesics in a neurosurgical ward setting. METHODS: A retrospective review of medical records for 71 children was completed. The patients underwent either cranial reconstruction (2002-2007) or craniotomies for intradural pathology (2005-2007) at British Columbia Children's Hospital. Outcome measures included pain control and adverse events. Comparison was made between patients receiving a CMI and patients receiving acetaminophen and codeine. RESULTS: Thirty-seven children received CMI on the ward (30 cranial reconstruction and 7 craniotomy), while 34 (10 cranial reconstruction and 24 craniotomy) received acetaminophen and codeine. There was no statistical difference in pain control. There was significantly more nausea on post-operative day one in the CMI group (p = 0.002). There were no other significant adverse events. CONCLUSIONS: These findings suggest that CMI is comparable to acetaminophen and codeine with respect to analgesia and serious side effects. We recommend the use of CMIs as an alternative when pain is poorly controlled in post-operative pediatric neurosurgical patients to prevent the potential adverse consequences of inadequate analgesia.

Analysis of Cytoplasmic and Secreted Proteins of Staphylococcus aureus Revealed Adaptive Metabolic Homeostasis in Response to Changes in the Environmental Conditions Representative of the Human Wound Site.

The pathogenesis of Staphylococcus aureus is mainly attributed to its capability to adjust to changes in environmental conditions, including those present on human skin or within a wound site. This study investigated the changes in the cytoplasmic and secreted proteins in S. aureus that occurred in response to alterations in the environmental parameters that could be found in the human wound site. In total, sixty differentially regulated cytoplasmic proteins were detected using a label-free quantification approach, and these proteins were classified into ten molecular functions: protein biosynthesis, glycolysis, signal transduction, metabolism, cell cycle, transport, energy generation, cell anchorage, nucleotide biosynthesis and unknown. These changes represented characteristic protein profiles when evaluated by principal component analysis. The bacterium responded to elevated NaCl at pH 6 by decreasing the abundance of the majority of cytoplasmic proteins, while at pH 8 there was an increase in the levels of cytoplasmic proteins in comparison to the untreated cells. The analysis of the secreted proteins showed that there was a high degree of difference in both the intensity and the distribution of many individual protein bands in response to environmental challenges. From these results, it was deduced that specific metabolic homeostasis occurred under each combination of defined environmental conditions.

PPAR-gamma agonist rosiglitazone reverses increased cerebral venous hydraulic conductivity during hypertension.

Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists have been shown to protect the cerebral vasculature, including the blood-brain barrier. In the present study, we investigated the effect of the PPAR-gamma agonist rosiglitazone on changes in venous permeability during chronic hypertension induced by nitric oxide synthase inhibition. Female Sprague-Dawley rats were either treated with N(G)-nitro-L-arginine methyl ester (L-NAME; 0.5 g/l in drinking water) for 5 wk (HTN; n = 8), L-NAME for 5 wk plus the PPAR-gamma agonist rosiglitazone (20 mg/kg in food) for the last 3 wk (HTN + Rosi; n = 5), L-NAME for 5 wk plus the superoxide dismutase mimetic Tempol (1 mmol/l in drinking water) for the last 3 wk (HTN + Tempol; n = 8), or were untreated controls (n = 9). Fluid filtration (J(v)/S) and hydraulic conductivity (L(p)) of cerebral veins were compared in vitro between groups after a step increase in pressure from 10 to 25 mmHg to mimic the change in hydrostatic pressure during acute hypertension. Hypertension increased J(v)/S by 2.2-fold and L(p) by 3.2-fold. Rosiglitazone treatment after 2 wk of hypertension completely reversed the increased J(v)/S and L(p) that occurred during hypertension, whereas Tempol had no effect. These results demonstrate that rosiglitazone was effective at reversing changes in venous permeability that occurred during chronic hypertension, an effect that does not appear to be related to its antioxidant properties. Our findings suggest that PPAR-gamma may be a key regulator of blood-brain barrier permeability and a potential therapeutic target during hypertension.

Electrophysiologically guided versus non-electrophysiologically guided selective dorsal rhizotomy for spastic cerebral palsy: a comparison of outcomes.

BACKGROUND: The perceived need for electrophysiological guidance (EPG) during selective dorsal rhizotomy (SDR) has limited the frequency with which SDR is performed. The need for EPG during SDR has been questioned. At our institution, of >200 children with SDR for spastic cerebral palsy, 22 children underwent SDR without EPG using clinical guidance (no EPG group). Electrophysiological stimulation was used to distinguish dorsal from ventral roots. The remainder had SDR with EPG. The purpose of this study was to compare outcomes between the groups having SDR with and without EPG. METHODS: The 22 patients in the no EPG group were matched with 22 controls in whom EPG was used, with respect to Gross Motor Function Classification System score (GMFCS) and age. The 12-month outcomes with respect to motor function score, hip adductor spasticity (Ashworth), hip abduction range of motion (ROM), quadriceps power [Medical Research Council (MRC)], WeeFIM, Quality of Upper Extremities Skills Test (QUEST), and incidence of complications were compared. RESULTS: There were no statistically significant differences preoperatively with respect to GMFCS, age, gross motor function, Ashworth or MRC scores, joint ROM, WeeFIM, or QUEST. At 1 year after SDR, there were no differences between the groups in the incidence of complications or outcome measures. Percentage of dorsal roots cut was similar, but the duration of surgery was significantly shorter in the no EPG group. CONCLUSIONS: There was no advantage of doing SDR with EPG compared to no EPG. SDR can reasonably be done in centers where EPG is not available, but electrophysiological stimulation to distinguish dorsal from ventral roots may be useful in avoiding complications.

The Uptake and Release of Amino Acids by Staphylococcus aureus at Mid-Exponential and Stationary Phases and Their Corresponding Responses to Changes in Temperature, pH and Osmolality.

Staphylococcus aureus is an important pathogen that is associated with nosocomial infections, as well as food poisoning. This bacterium is resistant to antimicrobial agents and can survive in a wide range of environmental conditions. The aim of this study was to measure the uptake and release of amino acids by S. aureus at mid-exponential and stationary phases of growth following exposure to a combination of conditions including variations in temperature, pH and NaCl. Bacterial cells were grown up to mid-exponential and stationary phases in tryptic soy broth (TSB), where the supernatants were collected for analyses of amino acids to determine the uptake and release characteristics. The uptake/release of amino acids was estimated by subtracting the initial levels of the free amino acids in the media from those measured at mid-exponential and stationary phases of growth. When cells were grown at ideal conditions, the analyses revealed that significant uptake of amino acids had occurred by stationary phase compared with the mid-exponential phase. A substantial release of valine and tyrosine into the external media was observed by cells at stationary phase. At both phases, the uptake and release patterns were significantly different between cells grown under ideal control conditions, when compared with those grown under various combinations of sub-optimal environmental conditions. The analyses of the supernatants harvested from controls and treatment groups at exponential phase indicated that the total uptake of amino acids was reduced approximately five times by cells grown with addition of 2.5% NaCl or with pH6 at 35°C, and 2-fold by cells grown at pH8 at 35°C. However, the final quantities of amino acids taken up by cells grown to stationary phase did not significantly alter between control and treated samples. Valine was found to be the most abundant amino acid that was significantly released into the media at stationary phase by both control and treated samples. It was evident that diverse environmental conditions resulted in differential patterns of amino acid uptake and release during adaptation to designated conditions.

Amino acids and proteomic acclimation of Staphylococcus aureus when incubated in a defined minimal medium supplemented with 5% sodium chloride.

Staphylococcus aureus is a versatile bacterium that can adapt to survive and grow in a wide range of salt concentrations. This study investigated whether the cells could mount a response to survive a challenge of 5% NaCl in a minimal incubation medium that would not support cell replication. Cells were grown in liquid culture, washed and then incubated for 90 min at 37°C in a medium that contained only glycine and glucose as substrates in PBS plus trace elements. The control cells were compared with a treatment group which was incubated with an additional 5% NaCl. Significantly more glycine was taken up by the cells exposed to 5% NaCl compared with control cells, and both groups consumed 99% of the glucose supplied. The NaCl treated cells had significantly higher cytoplasmic levels of proline and glutamic acid as well as lower levels of alanine and methionine compared with the controls (p < 0.05). The levels of the two major cytoplasmic amino acids, aspartic acid and glycine, remained constant in control and treated cells. Proteomic analyses revealed that 10 proteins showed differential responses between the control and treatment groups. The reductions in proteins were primarily associated with processes of protein biosynthesis, pathogenicity, and cell adhesion. Since cell numbers remained constant during the incubation period in minimal medium, it was concluded that there was no cell division to support population growth. The results provided evidence that the cells in the minimal medium exposed to the NaCl treatment underwent in situ homeostatic changes to adjust to the new environmental conditions. It was proposed that this represented a phenotypic shift to form cells akin to small colony variants, with lower metabolic rates and lower levels of key proteins associated with pathogenicity.

Altered amino acid excretion in children with autism.

Autism is a complex and life-long behavioural disorder of unknown aetiology. Recent reports have indicated the involvement of digestive tract dysfunction and possible complications from inadequate nutrition. In this study, 34 autistic children (12 untreated and 22 receiving therapeutic treatments related to digestive function and nutritional uptake) and 29 control subjects (all 5-15 years of age) were investigated to determine whether there were any anomalies in the urinary excretion of amino acids, glucose, sucrose, arabinose and tartaric acid using GC/FID and GC/MS analysis techniques. Significantly lower relative urinary levels of essential amino acids were revealed for both the untreated (mean +/- SEM, 32.53 +/- 3.09%) and treated (31.98 +/- 2.87%) autistic children compared with the controls (37.87 +/- 1.50%). There were no significant differences in measured excretions of sugars or tartaric acid. It was concluded that the untreated autistic children had evidence of altered metabolic homeostasis.