Pediatric cartilaginous lateral femoral condyle Hoffa fracture: a case report and review of the literature

INTRODUCTION

Hoffa fractures are challenging coronally-oriented articular injuries of the femoral condyle. These fractures are rare in adults and extremely rare in the skeletally immature, with few cases reported in literature. To prevent mal- or non-union, Hoffa fractures require prompt surgical stabilisation with anatomic reduction and internal fixation.

CASE REPORT

We discuss the case of a lateral distal femoral condyle cartilaginous Hoffa fracture in a ten-year-old male patient. The patient presented after a football non-contact "twist and pop" injury with radiographic imaging described as an osteochondritis dissecans lesion. An MRI was obtained which demonstrated a lateral distal femoral condyle osteochondral fracture. An operative plan was formulated to perform arthroscopic reduction and bio-compression screw fixation to minimize damage to the physis and surrounding tissues. Hyperflexion of the knee allowed for anatomic fracture reduction with the placement of 2 bio-compression screws serving as maintenance of fixation. The patient did well postoperatively and returned to full activity after 6 months.

CONCLUSION

Hoffa fractures in the pediatric population are rare and can occur not only through bone but also through the thick chondral layer in younger patients. These are extremely difficult to diagnose through X-Ray alone. The prompt use of MRI imaging allows for operative fixation in a timely fashion, while an arthroscopic-only approach allows for minimal tissue damage. With an appropriate fracture type, hyper-flexion reduces and stabilizes the fracture, permitting the placement of minimally invasive bio-compression fixation.

Prevalence of elevated blood lead levels and risk factors among children living in Patna, Bihar, India 2020

Childhood lead exposure remains a key health concern for officials worldwide, contributing some 600,000 new cases of intellectually disabled children annually. Most children affected by high exposure to lead live in low- and middle-income countries. The leaded gasoline phase out in India was completed in 2000. Yet, in 2020, an estimated 275 million children aged 0 to 9 years had blood lead levels (BLLs) ≥ 5 μg/dL known to adversely affect intelligence and behavior. Lead sources reported in India include spices, cookware, paint, traditional medicines and cosmetics, and lead-acid battery recycling and repair. However, their relative contribution has not been characterized. More than 200 lead pollution sites related to battery recycling and repair activities were identified in Bihar and Jharkhand, India. Ninety percent of the recycling sites had soil lead concentrations exceeding the US Environmental Protection Agency's standards. We compared blood and environmental lead levels in two groups of children in Patna, Bihar. Households in proximity to battery recycling operations (Proximal n = 67) versus households distal to these operations (Distal n = 68). The average age of children was 40 months; 46% were female. Overall, the geometric mean (GM) BLL was 11.6 μg/dL. GM BLLs of children in Proximal and Distal households were not significantly different (10.2 μg/dL vs. 13.1 μg/dL respectively; p≤0.07). About 87% children, 56 Proximal and 62 Distal had BLLs ≥5 μg/dl. Lead concentrations in environmental samples were significantly higher in Proximal households (soil mean 9.8 vs. 1.6 μg/ft2; dust mean 52.9 vs. 29.9 μg/ft2 p<0.001; Proximal vs. Distal respectively) whereas concentrations in all spices were higher in Distal households (mean 46.8 vs 134.5 ppm p<0.001; Proximal vs. Distal respectively), and turmeric (mean 59.4 vs. 216.9 ppm Proximal vs. Distal respectively). In multivariate analyses for all children lead in spices and turmeric and number of rooms in the house were significant while for the Proximal group only lead in spices remained in the model. The predictive value of these models was poor. For the Distal group, a model with lead concentration in spices, turmeric and soil and number of rooms in the house was a much better fit. Of the 34 water samples collected, 7 were above the Indian standard of 10 ppb for lead in drinking water (2 in the Proximal area, 5 in the Distal area). Children in Patna, Bihar, India are exposed to multiple sources of lead, with lead levels in house dust and loose, locally sourced spices the most likely to increase blood lead levels. A holistic approach to blood lead testing and source identification and remediation are necessary to prevent lead exposure.

Multiscale Self-Assembly of Distinctive Weblike Structures from Evaporated Drops of Dilute American Whiskeys

When a sessile droplet of a complex mixture evaporates, its nonvolatile components may deposit into various patterns. One such phenomena, the coffee ring effect, has been a topic of interest for several decades. Here, we identify what we believe to be a fascinating phenomenon of droplet pattern deposition for another well-known beverage-what we have termed a "whiskey web". Nanoscale agglomerates were generated in diluted American whiskeys (20-25% alcohol by volume), which later stratified as microwebs on the liquid-air interface during evaporation. The web's strandlike features result from monolayer collapse, and the resulting pattern is a function of the intrinsic molecular constituents of the whiskey. Data suggest that, for our conditions (diluted 1.0 μL drops evaporated on cleaned glass substrates), whiskey webs were unique to diluted American whiskey; however, similar structures were generated with other whiskeys under different conditions. Further, each product forms their own distinct pattern, demonstrating that this phenomenon could be used for sample analysis and counterfeit identification.

Mediator and moderator effects on the relationship between HIV-positive status disclosure concerns and health-related quality of life

HIV-related stigma and the effect on quality of life is an on-going public health concern despite decades of education, prevention, and intervention efforts. The main purposes of this study were to examine the mediating role of four coping styles and the moderating role of gender on the relationship between HIV-positive status disclosure concerns and eight health-related quality of life outcomes. Data were collected from 346 women and men living with HIV. Results indicated that two coping styles - acquiring social support and positive reframing - mediated the negative relationship between disclosure concerns and health-related quality of life outcomes. There was no support for a moderated mediation. Interventions aimed at helping people living with HIV should focus on identifying and acquiring coping styles that transform perceptions of HIV-related stigma to support disclosure and improve health-related quality of life.

Change in Biotypic Diversity of Russian Wheat Aphid (Hemiptera: Aphididae) Populations in the United States

A key component of Russian wheat aphid, Diuraphis noxia (Kurdjumov), management has been through planting resistant wheat cultivars. A new biotype, RWA2, appeared in 2003 which caused widespread damage to wheat cultivars containing the Dn4 gene. Biotypic diversity in Russian wheat aphid populations has not been addressed since 2005 when RWA2 dominated the biotype complex. Our objectives were to determine the biotypic diversity in the Central Great Plains and Colorado Plateau at regional (2010, 2011, 2013) and local (2012) levels and detect the presence of new Russian wheat aphid biotypes. Regional and within-field aphid collections were screened against Russian wheat aphid-resistant wheat genotypes containing genes Dn3, Dn4, Dn6, Dn7, Dn9, CI2401; and resistant barley STARS 9301B. In 2010, all aphid collections from Texas were avirulent to the Dn4 resistance gene in wheat. Regional results revealed Dn4 avirulent RWA6 was widespread (55-84%) in populations infesting wheat in both regions. Biotypes RWA1, 2, and 3/7 were equally represented with percentages<20% each while RWA8 was rarely detected. Combining percentages of RWA1, 6, and 8 across regions to estimate avirulence to Dn4 gene revealed high percentages for both 2011 (64-80%) and 2013 (69-90%). In contrast, the biotype structure at the local level differed where biotype percentages varied up to ≥2-fold between fields. No new biotypes were detected; therefore, Dn7, CI2401, and STARS9301B remained resistant to all known Russian wheat aphid biotypes. This study documents a shift to Dn4 avirulent biotypes and serves as a valuable baseline for biotypic diversity in Russian wheat aphid populations prior to the deployment of new Russian wheat aphid-resistant wheat cultivars.

Information needs for the OR and PACU electronic medical record

OBJECTIVE

The amount of clinical information that anesthesia providers encounter creates an environment for information overload and medical error. In an effort to create more efficient OR and PACU EMR viewer platforms, we aimed to better understand the intraoperative and post-anesthesia clinical information needs among anesthesia providers.

MATERIALS AND METHODS

A web-based survey to evaluate 75 clinical data items was created and distributed to all anesthesia providers at our institution. Participants were asked to rate the importance of each data item in helping them make routine clinical decisions in the OR and PACU settings.

RESULTS

There were 107 survey responses with distribution throughout all clinical roles. 84% of the data items fell within the top 2 proportional quarters in the OR setting compared to only 65% in the PACU. Thirty of the 75 items (40%) received an absolutely necessary rating by more than half of the respondents for the OR setting as opposed to only 19 of the 75 items (25%) in the PACU. Only 1 item was rated by more than 20% of respondents as not needed in the OR compared to 20 data items (27%) in the PACU.

CONCLUSION

Anesthesia providers demonstrate a larger need for EMR data to help guide clinical decision making in the OR as compared to the PACU. When creating EMR platforms for these settings it is important to understand and include data items providers deem the most clinically useful. Minimizing the less relevant data items helps prevent information overload and reduces the risk for medical error.

Characterization of eight Russian wheat aphid (Hemiptera: Aphididae) biotypes using two-category resistant-susceptible plant responses

Eight biotypes of the Russian wheat aphid, Diuraphis noxia (Kurdjumov), have been discovered in the United States since 2003. Biotypes are identified by the distinct feeding damage responses they produce on wheat carrying different Russian wheat aphid resistance genes, namely, from Dn1 to Dn9. Each Russian wheat aphid biotype has been named using plant damage criteria and virulence categories that have varied between studies. The study was initiated to compare the plant damage caused by all the eight known Russian wheat aphid biotypes, and analyze the results to determine how Russian wheat aphid virulence should be classified. Each Russian wheat aphid biotype was evaluated on 16 resistant or susceptible cereal genotypes. Plant damage criteria included leaf roll, leaf chlorosis, and plant height. The distribution of chlorosis ratings followed a bimodal pattern indicating two categories of plant responses, resistant or susceptible. Correlations were significant between chlorosis ratings and leaf roll (r(2) = 0.72) and between chlorosis ratings and plant height (r(2) = 0.48). The response of 16 cereal genotypes to feeding by eight Russian wheat aphid biotypes found RWA1, RWA2, RWA6, and RWA8 to differ in virulence, while Russian wheat aphid biotypes RWA3, RWA4, RWA5, and RWA7 produced similar virulence profiles. These biotypes have accordingly been consolidated to what is hereafter referred to as RWA3/7. Our results indicated that the five main biotypes RWA1, RWA2, RWA3/7, RWA6, and RWA8 can be identified using only four wheat genotypes containing Dn3, Dn4, Dn6, and Dn9.

Influenza and congenital anomalies: a systematic review and meta-analysis

STUDY QUESTION

Does first trimester maternal influenza infection increase the risk of non-chromosomal congenital anomalies (CA)?

SUMMARY ANSWER

First trimester maternal influenza exposure is associated with raised risk of a number of non-chromosomal CA, including neural tube defects, hydrocephaly, congenital heart defects, cleft lip, digestive system defects and limb reduction defects.

WHAT IS KNOWN ALREADY

Hyperthermia is a well-established risk factor for neural tube defects. Previous studies suggest influenza may be a risk factor not only for neural tube defects, but also other CA. No systematic review has previously been undertaken.

STUDY DESIGN, SIZE, DURATION

Systematic review and meta-analysis. A search of EMBASE and PUBMED was performed for English and Dutch studies published up to July 2013. A total of 33 studies (15 case-control, 10 cohort and 8 ecological) were included in the systematic review of which 22 studies were included in the meta-analysis.

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

A total of 29 542 babies with congenital anomaly (1112 exposed) from case-control studies and 1608 exposed pregnancies resulting in 56 babies with congenital anomaly from cohort studies were included in the meta-analysis. Maternal influenza exposure was defined as any reported influenza, influenza-like illness or fever with flu, with or without serological or clinical confirmation during the first trimester of pregnancy. Data for 24 (sub)groups with congenital anomaly available from ≥3 studies were analysed using the DerSimonian-Laird random effects model. The hypothesis of publication bias was assessed using funnel plots and risk of bias of included studies was assessed using a slightly modified version of the Newcastle-Ottawa scale.

MAIN RESULTS AND THE ROLE OF CHANCE

First trimester maternal influenza exposure was associated with an increased risk of any congenital anomaly [adjusted odds ratio (AOR) 2.00, 95% CI: 1.62-2.48], neural tube defects [odds ratio (OR) 3.33, 2.05-5.40], hydrocephaly (5.74, 1.10-30.00), congenital heart defects (1.56, 1.13-2.14), aortic valve atresia/stenosis (AOR 2.59, 1.21-5.54), ventricular septal defect (AOR 1.59, 1.24-2.14), cleft lip (3.12, 2.20-4.42), digestive system (1.72, 1.09-2.68) and limb reduction defects (2.03, 1.27-3.27). An increased risk for cleft lip (but not for cleft palate) was also reported by ecological studies not included in the meta-analysis. Study outcomes reported for 27 subgroups of congenital anomaly could not be included in the meta-analysis. Visual inspection of funnel plots did not suggest evidence for publication bias.

LIMITATIONS, REASONS FOR CAUTION

This study enrolled observational studies that can be subject to limitations such as confounding, retrospective maternal exposure reports and non-response of intended participants. Influenza exposed pregnancies can also have been exposed to influenza related medication.

WIDER IMPLICATIONS OF THE FINDINGS

Prevention of influenza in pregnant women may reduce congenital anomaly risk, and would be relevant to more than just neural tube defects. More research is needed to determine whether influenza and/or its related medication is teratogenic, to determine the role of hyperthermia in teratogenicity and the role of other environmental factors such as nutritional status in determining susceptibility.

Biosurfactants for cosmetic applications

Synopsis Biosurfactants are biologically-produced, natural surface active agents and are synthesized by a range of microorganisms. These compounds include glycolipids, lipopeptides and phospholipids. The yields of biosurfactants in microbial fermentations may be as high as 150g l(-1) and may be increased by optimizing production conditions and by strain improvement. Biosurfactants display very low critical micelle concentration (CMC) values when compared with conventional surfactants and are stable at a wide range of temperatures, pH values and salinities. They show many promising characteristics for cosmetic applications.

An overview of the biology and status of undulate ray Raja undulata in the north-east Atlantic Ocean

The undulate ray Raja undulata is one of the lesser-known skates occurring on the continental shelf of the north-east Atlantic Ocean. It is patchily distributed throughout its range, with sites of local abundance in the central English Channel and off the coasts of Ireland, France, Spain and Portugal. Raja undulata is most abundant in coastal waters (<50 m deep) and is often found in proximity to large estuaries, rias and bays. It is a relatively large-bodied species, attaining a maximum total length (L(T) ) of at least 114 cm, with females maturing at an L(T) of c. 84 cm in Portuguese waters. Although infrequently taken in existing trawl surveys, it can be locally abundant in certain areas, where it can be the dominant skate species. Given its large size, patchy distribution and concern over the possibilities of localized depletions, the IUCN listed R. undulata as an endangered species and, since 2009, the European Union has established regulations to prohibit commercial fisheries landing the species. Given the increased interest in the species, a synopsis of current knowledge is provided, and available data from internationally co-ordinated trawl surveys presented.

Infusion with the antioxidant N-acetylcysteine attenuates early adaptive responses to exercise in human skeletal muscle

AIM

Production of reactive oxygen species (ROS) in skeletal muscle is markedly increased during exercise and may be essential for exercise adaptation. We, therefore, investigated the effects of infusion with the antioxidant N-acetylcysteine (NAC) on exercise-induced activation of signalling pathways and genes involved in exercise adaptation in human skeletal muscle.

METHODS

Subjects completed two exercise tests, 7 days apart, with saline (control, CON) or NAC infusion before and during exercise. Exercise tests comprised of cycling at 71% VO(2peak) for 45 min, and then 92% VO(2peak) to fatigue, with vastus lateralis biopsies at pre-infusion, after 45-min cycling and at fatigue.

RESULTS

Analysis was conducted on the mitogen-activated protein kinase signalling pathways, demonstrating that NAC infusion blocked the exercise-induced increase in JNK phosphorylation, but not ERK1/2, or p38 MAPK. Nuclear factor-κB p65 phosphorylation was unaffected by exercise; however, it was reduced in NAC at fatigue by 14% (P < 0.05) compared with pre-infusion. Analysis of exercise and/or ROS-sensitive genes demonstrated that exercise-induced mRNA expression is ROS dependent of MnSOD, but not PGC-1α, interleukin-6, monocyte chemotactic protein-1, or heat-shock protein 70.

CONCLUSION

These results suggest that inhibition of ROS attenuates some skeletal muscle cell signalling pathways and gene expression involved in adaptations to exercise.

Disseminated visceral coccidiosis in Eurasian cranes (Grus grus) in the UK

Clinical disease and mortalities due to disseminated visceral coccidiosis were identified for the first time in a group of captive juvenile Eurasian cranes (Grus grus) in the UK during 2008. Presumptive diagnosis was made from the finding of granulomatous nodules in the liver, spleen and other organs at gross postmortem examination, and confirmed histologically by the presence of intracellular coccidial stages within lesions. The species of coccidian was determined to be Eimeria reichenowi on the basis of faecal oocyst morphology and sequencing of 18S rDNA by PCR. A further outbreak of clinical disease occurred in the same enclosure in 2009, affecting a new group of juvenile Eurasian cranes and demoiselle cranes (Anthropoides virgo) and indicating the persistence of infective oocysts in the environment. Clinical sampling of birds during both years demonstrated positive results from examination of both faecal samples and peripheral blood smears.

A comparison of parametric and non-parametric approaches to target-controlled infusion of propofol

Nineteen adult patients of either gender received intravenous infusions of propofol, scaled to estimated lean body mass (LBM), for 150 minutes as part of a balanced anaesthetic. Arterial blood was assayed for whole blood propofol. The first subject received propofol at a fixed rate of 0.058 mg x min(-1) x kg(LBM)(-1). Subsequent groups received variable rate infusions based on the ratio of the infusion rate to the propofol concentration at each sampling point in the previous group, multiplied by the target concentration. After groups of one, two, five and 11 subjects, the median weighted residual was 0.040 and median absolute weighted residual was 0.153. Population pharmacokinetic analysis of the final group of six females and five males, aged 29 to 70 years and of 16.5 to 44.2% body fat, resulted in a two compartment pharmacokinetic model with coefficients and standard errors of V = 0.102 (0.0155) l/kg(LBM), V2 = 0.257 (0.079) l/kg(LBM), k10 = 0.423 (0.069)/min, k12 = 0.222 (0.051)/min, k21 = 0.084 (0.02)/min and clearance = 0.0418 (0.0023) L x min(-1) x kg(LBM)(-1). The only significant covariate was LBM. Within infusion data improved prediction when compared with data derived in previous studies from random observations.

Catecholamine neurotransmitters and the heart

The possible role of adrenaline as a cardiac neurotransmitter was studied following its infusion in 6 healthy volunteers. After the end of the infusion, heart rate remained elevated for several hours despite a rapid fall in plasma adrenaline concentration. Stimulation of sympathetic activity by standing caused a further marked increase in heart rate, which was greater than that found on a control occasion. These effects were abolished or reduced by pretreatment with either desipramine or (in the dog) alpha-methyl-p-tyrosine, suggesting that they depend both on uptake of the adrenaline into sympathetic nerve endings during infusion and on increased release of endogenous noradrenaline. These results are consistent with stimulation of the beta-presynaptic receptor by adrenaline when re-released from sympathetic nerves.

The experiences of adults with intellectual disabilities and their carers in general hospitals: a focus group study

BACKGROUND

People with intellectual disabilities (ID) have higher levels of health needs compared with the general population, many of which are unrecognised and unmet. While there has been interest and research into the primary health provision for this group, there has been a more limited focus on addressing their care received in general hospitals. Access to health care has predominated in the literature, with less attention being paid to the experiences of people with ID as users of general hospital care.

METHOD

A qualitative focus group methodology was used. Eleven adults with ID, nine parents and five paid carers of adults with ID participated. The focus groups were audiotaped and transcriptions were analysed using principles of grounded theory.

RESULTS

The analysed data highlighted key themes identified from the experiences of participants. These were the interrelated issues of feelings, particularly anxiety and fear, communication and behaviour problems; the practicalities of being in or attending hospitals, including the role played by carers; and issues around perceived discrimination and negative comments.

CONCLUSIONS

The experiences of participants in this study concur with and add to concern expressed in recent reports and published research. Wide ranging implications are discussed for further research, wider policy development, clinical practice, local health service provision and education of health professionals.

Modeling Uhthoff's phenomenon in MS patients with internuclear ophthalmoparesis

OBJECTIVE

The goal of this investigation was to demonstrate that internuclear ophthalmoparesis (INO) can be utilized to model the effects of body temperature-induced changes on the fidelity of axonal conduction in multiple sclerosis (Uhthoff's phenomenon).

METHODS

Ocular motor function was measured using infrared oculography at 10-minute intervals in patients with multiple sclerosis (MS) with INO (MS-INO; n = 8), patients with MS without INO (MS-CON; n = 8), and matched healthy controls (CON; n = 8) at normothermic baseline, during whole-body heating (increase in core temperature 0.8 degrees C as measured by an ingestible temperature probe and transabdominal telemetry), and after whole-body cooling. The versional disconjugacy index (velocity-VDI), the ratio of abducting/adducting eye movements for velocity, was calculated to assess changes in interocular disconjugacy. The first pass amplitude (FPA), the position of the adducting eye when the abducting eye achieves a centrifugal fixation target, was also computed.

RESULTS

Velocity-VDI and FPA in MS-INO patients was elevated (p < 0.001) following whole body heating with respect to baseline measures, confirming a compromise in axonal electrical impulse transmission properties. Velocity-VDI and FPA in MS-INO patients was then restored to baseline values following whole-body cooling, confirming the reversible and stereotyped nature of this characteristic feature of demyelination.

CONCLUSIONS

We have developed a neurophysiologic model for objectively understanding temperature-related reversible changes in axonal conduction in multiple sclerosis. Our observations corroborate the hypothesis that changes in core body temperature (heating and cooling) are associated with stereotypic decay and restoration in axonal conduction mechanisms.

The use of 18-fluoro-dihydroxyphenylalanine and 18-fluorodeoxyglucose positron emission tomography scanning in the assessment of metaiodobenzylguanidine-negative phaeochromocytoma

123I-metaiodobenzylguanidine (123I-MIBG) scintigraphy scanning is commonly used in the imaging of phaeochromocytoma (and paraganglioma) to confirm the site of disease and whether any spread has occurred. However, 123I-MIBG imaging is negative in 15% of cases of benign phaeochromocytoma and around 50% of cases of malignant phaeochromocytoma. In recent years, positron emission tomography (PET) scanning using various different radiotracers has been shown to be a good alternative or supplementary investigation in phaeochromocytoma. We present the cases of four patients with symptoms and signs suggestive of phaeochromocytoma, but who had negative 123I-MIBG scans, and illustrate the usefulness of 18-fluoro-dihydroxyphenylalanine PET scanning in their assessment. In one of the patients, we illustrate how fluorodeoxyglucose PETscanning can provide useful information about the extent of malignant disease. These illustrative cases lend further support for the use of PET scanning in the assessment of phaeochromocytoma and suggest that it may have a particularly important role in the investigation of patients in whom 123I-MIBG scanning is negative.

The heritability of plasma homocysteine, and the influence of genetic variation in the homocysteine methylation pathway

BACKGROUND

The extent of genetic influence on plasma homocysteine, a risk factor for ischaemic heart disease, is uncertain. Many association studies have investigated common polymorphisms and their role in hyperhomocysteinaemia, but only the thermolabile variant of methylene tetrahydrofolate reductase (MTHFR) has shown an association (small but robust).

AIM

To estimate the heritability of plasma homocysteine and the contributions of well-studied common SNPs in the three main candidate genes in the homocysteine methylation pathway.

DESIGN

Twin study.

METHODS

We studied 216 monozygotic and 790 dizygotic pairs of twins; all were women. Blood was collected after overnight fasting for measurement of homocysteine, folate, vitamin B12, and extraction of DNA. Heritability was estimated by structural modelling, including correction for known environmental influences, particularly serum folate. The frequency of a common coding SNP in MTHFR and methionine synthase (MTR), and two coding SNPs in methionine synthase reductase (MTRR) were measured in dizygotic twins by ABI 7700 Sequence Detection, and the contribution of each to homocysteine variance was determined.

RESULTS

The heritability of homocysteine was 57% (95%CI 51-63%). The highest contribution to homocysteine was serum folate, accounting for 10.13% of variance. This was twice the total genetic contribution of 4.56%, and only the C1763T SNP of MTRR showed significant association with homocysteine.

DISCUSSION

Homocysteine has one of the highest heritabilities of common risk factors for ischaemic heart disease. This is not accounted for by the commonly studied SNPs in MTHFR, MTR and MTRR.

Grand Rounds at the British Hypertension Society: renal artery stenosis

Renal artery angioplasty for renovascular hypertension is a controversial subject with considerable data but few certainties. This article is a summary of the Grand Round on Renovascular Hypertension held at the British Hypertension Society Annual Conference in September 2006.

Transient conduction block following acute peripheral nerve ischemia

We studied the effects of transient focal ischemia on the electrophysiologic function of rat sciatic nerves. Focal and generalized impairment of impulse conduction, measured by falling evoked muscle and nerve compound action potential amplitudes, occurred within 10 minutes of femoral artery occlusion. Conduction failure reached a nadir at 45-60 minutes and then improved to normal within 24 hours. Fastest motor and mixed nerve conduction velocities were reduced less than 15% of baseline values during the period of acute conduction block. There were no detectable morphological abnormalities at the site of conduction failure. Transient ischemia produces reversible conduction block without evident structural changes. The fall in amplitude without significant conduction slowing implies that slower conducting myelinated fibers are relatively more sensitive to the effect of acute ischemia.

Use of an enzyme-linked immunosorbent asay to diagnose avian tuberculosis in a captive collection of wildfowl

The current study assessed the diagnostic accuracy of an enzyme-linked immunosorbent assay (ELISA) and evaluated it as a diagnostic screening aid for avian tuberculosis (TB) in a wildfowl collection at the Wildfowl and Wetlands Trust Centre at Llanelli, Wales, U.K.. Four hundred and eighteen birds of the collection, including geese, ducks, and swans, were screened for mycobacterial antibody levels. Of those birds tested, 40 died during the period of this study and gross post mortem examinations were performed. The ELISA showed a sensitivity of 76.9% and a specificity of 55.6% using post-mortem findings as the 'gold standard'. Thirteen of the examined birds showed evidence of avian TB at necropsy. In addition, liver and spleen biopsies of 19 birds were examined histopathologically. There was minimal agreement between gross post mortem and histopathological findings. PCR performed on 13 of the specimens prepared for histopathology did not identify the presence of mycobacterial DNA. The findings reveal a need for further research to improve the sensitivity and specificity of this ELISA and the accurate diagnosis of avian TB.

Differential expression of adenylyl cyclase subtypes in human cardiovascular system

In human myocardium, beta1-adrenoceptor stimulation achieves maximal inotropic response but less than 50% of maximal adenylyl cyclase activation, whereas the reverse is true of the beta2-adrenoceptor. Four types of adenylyl cyclase, type IV-VII, have been described in mammalian heart, but their expression and relative distribution in human heart and blood vessels is not known. We found that type IV, V, VI and VII adenylyl cyclases were all expressed in cardiomyocytes. Whereas types IV and VII RNA were more abundant in extra-cardiac than cardiac tissues, both absolute and relative expression of type VI was greatest in heart, and lower in tissues lacking a beta1-adrenoceptor. Type V expression was virtually confined to atrium. In situ mRNA hybridisation showed that the beta1-adrenoceptor co-localised with type VI adenylyl cyclase but not other subtypes in juxtoglomerular cells of human kidney. The tissue specific expression of these adenylyl cyclase subtypes may favour its coupling to corresponding receptors expressed in the given tissue type.

N-acetylcysteine enhances muscle cysteine and glutathione availability and attenuates fatigue during prolonged exercise in endurance-trained individuals

The production of reactive oxygen species in skeletal muscle is linked with muscle fatigue. This study investigated the effects of the antioxidant compound N-acetylcysteine (NAC) on muscle cysteine, cystine, and glutathione and on time to fatigue during prolonged, submaximal exercise in endurance athletes. Eight men completed a double-blind, crossover study, receiving NAC or placebo before and during cycling for 45 min at 71% peak oxygen consumption (VO2 peak) and then to fatigue at 92% VO2 peak. NAC was intravenously infused at 125 mg.kg(-1).h(-1) for 15 min and then at 25 mg.kg(-1).h(-1) for 20 min before and throughout exercise. Arterialized venous blood was analyzed for NAC, glutathione status, and cysteine concentration. A vastus lateralis biopsy was taken preinfusion, at 45 min of exercise, and at fatigue and was analyzed for NAC, total glutathione (TGSH), reduced glutathione (GSH), cysteine, and cystine. Time to fatigue at 92% VO2 peak was reproducible in preliminary trials (coefficient of variation 5.6 +/- 0.6%) and with NAC was enhanced by 26.3 +/- 9.1% (NAC 6.4 +/- 0.6 min vs. Con 5.3 +/- 0.7 min; P <0.05). NAC increased muscle total and reduced NAC at both 45 min and fatigue (P <0.005). Muscle cysteine and cystine were unchanged during Con, but were elevated above preinfusion levels with NAC (P <0.001). Muscle TGSH (P <0.05) declined and muscle GSH tended to decline (P=0.06) during exercise. Both were greater with NAC (P <0.05). Neither exercise nor NAC affected whole blood TGSH. Whereas blood GSH was decreased and calculated oxidized glutathione increased with exercise (P <0.05), both were unaffected by NAC. In conclusion, NAC improved performance in well-trained individuals, with enhanced muscle cysteine and GSH availability a likely mechanism.

Assessment of lymphocyte-mediated cytotoxicity using flow cytometry

Cytotoxic lymphocytes, including cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells, kill target cells by releasing granules containing perforin and granzymes, and/or via Fas-Fas ligand interactions. Both pathways lead to prompt activation within target cells of caspase cascades responsible for apoptosis induction and cell death. We have utilized cell-permeable fluorogenic caspase substrates and multiparameter flow cytometry to detect caspase activation in target cells, and applied these tools to quantify and visualize cytotoxic lymphocyte activities. This novel assay, referred to as the flow cytometric cytotoxicity (FCC) assay, is a nonradioactive single-cell-based assay that provides a more rapid, biologically informative, and sensitive approach to measure cytotoxic lymphocyte activity when compared to other assays such as the 51chromium (51Cr) release assay. In addition, the FCC assay can be used to study CTL-mediated killing of primary target cells of different cell lineages that are frequently not amenable to study by the 51Cr release assay. Furthermore, the FCC assay enables evaluation of the phenotype and fate of both target and effector cells, and as such, provides a useful new approach to illuminate the biology of cytotoxic lymphocytes.

Chemokine stimulation of human peripheral blood T lymphocytes induces rapid dephosphorylation of ERM proteins, which facilitates loss of microvilli and polarization

Lymphocyte microvilli mediate initial rolling-adhesion along endothelium but are lost during transmigration from circulation to tissue. However, the mechanism for resorption of lymphocyte microvilli remains unexplored. We show that chemokine stimulation of human peripheral blood T (PBT) cells is sufficient to induce rapid resorption of microvilli. Microvilli in other cells are regulated by ezrin/radixin/moesin (ERM) proteins, which link the plasma membrane to the cortical F-actin cytoskeleton; maintenance of these linkages requires ERM activation, reflected by phosphorylation at a specific carboxy-terminal threonine residue. Carboxyphosphorylated-ERM (cpERM) proteins in resting PBT cells show a punctate peripheral distribution consistent with localization to microvilli. cpERM dephosphorylation begins within seconds of stimulation by chemokines (stromal derived factor 1 alpha [SDF-1 alpha] or secondary lymphoid tissue cytokine), and ERM proteins lose their punctate distribution with kinetics paralleling the loss of microvilli. The cpERM proteins are preferentially associated with the cytoskeleton at rest and this association is lost with chemokine-induced dephosphorylation. Transfection studies show that a dominant-negative ERM construct destroys microvilli, whereas a construct mimicking cpERM facilitates formation of microvilli, retards chemokine-induced loss of microvilli, and markedly impairs chemokine-induced polarization. Thus, chemokine induces rapid dephosphorylation and inactivation of cpERM, which may in turn facilitate 2 aspects of cytoskeletal reorganization involved in lymphocyte recruitment: loss of microvilli and polarization.

The Methylerythritol Phosphate Pathway and its Significance as a Novel Drug Target

Isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) are the precursors for all isoprenoid compounds. Two pathways are found in Nature for their biosynthesis. The mevalonate (MVA) pathway is found in eukaryotes, algae, archae and some gram-positive bacteria. Gram-negative bacteria, plants and some gram-positive bacteria utilize the methyl erythritol phosphate (MEP) pathway. The distribution and the orthogonal nature of the pathways make the MEP pathway an attractive new target for antibiotics and herbicides. The MEP pathway is essential for bacterial viability. Inhibitors to the MEP pathway represent a "dual-use technology" because potential targets include potential biological warfare agents in addition to common human pathogens. The CDC has three categories designated for Biological Diseases/Agents. Three of the six entities designated as the highest priority (Category A) are organisms that utilize, or appear to utilize, the MEP pathway. Among the 12 second highest priority agents (Category B) listed, 8 are organisms that appear to utilize the MEP pathway. Common human pathogens that can be targeted include the organisms responsible for peptic ulcers, tuberculosis, malaria, food safety threats, and sexually transmitted diseases. There is so far only one inhibitor reported that specifically blocks the MEP pathway and is being investigated clinically. This compound, fosmidomycin, has been shown to be somewhat effective in treating Plasmodium falciparum, the parasite responsible for malaria. We foresee that new MEP pathway inhibitors will open up an entirely new class of antibiotics. An MEP pathway intermediate has also been shown to be the most potent gammadelta T cell activator.

N-acetylcysteine infusion alters blood redox status but not time to fatigue during intense exercise in humans

Infusion of the antioxidant N-acetylcysteine (NAC) reduces fatigability in electrically evoked human muscle contraction, but due to reported adverse reactions, no studies have investigated NAC infusion effects during voluntary exercise in humans. We investigated whether a modified NAC-infusion protocol (125 mg. kg(-1). h(-1) for 15 min, then 25 mg. kg(-1). h(-1)) altered blood redox status and enhanced performance during intense, intermittent exercise. Eight untrained men participated in a counterbalanced, double-blind, crossover study in which they received NAC or saline (control) before and during cycling exercise, which comprised three 45-s bouts and a fourth bout that continued to fatigue, at 130% peak oxygen consumption. Arterialized venous blood was analyzed for glutathione status, hematology, and plasma electrolytes. NAC infusion induced no severe adverse reactions. Exercise decreased the reduced glutathione (P < 0.005) and increased oxidized glutathione concentrations (P < 0.005); NAC attenuated both effects (P < 0.05). NAC increased the rise in plasma K(+) concentration-to-work ratio (P < 0.05), indicating impaired K(+) regulation, although time to fatigue was unchanged (NAC 102 +/- 45 s; saline 107 +/- 53 s). Thus NAC infusion altered blood redox status during intense, intermittent exercise but did not attenuate fatigue.

Better blood pressure control: how to combine drugs

Prospective comparisons of different drug classes have shown that differences in blood pressure control, rather than differences between drug classes, have the over-riding influence on overall outcome. The same studies have also reinforced the need, in the majority of patients, to use combinations of drugs in order to achieve the target of <140/85 mmHg. By contrast, most patients in routine practice receive single agents and consequently fail to achieve target blood pressure. This failure reflects in part the emphasis in individual studies and subsequent guidelines on comparison of individual drugs. In this article we show how the consistency of both theory and a broad range of evidence permits a didactic approach to combination therapy. Our advice is based on the growing recognition that essential hypertension and its treatment fall into two main categories. Younger Caucasians usually have renin-dependent hypertension that responds well to angiotensin-converting-enzyme inhibition or angiotensin receptor blockade (A) or ss blockade (B). Most other patients have low-renin hypertension that responds better to calcium channel blockade (C) or diuretics (D). These latter drugs activate the renin system rendering patients responsive to the addition of renin suppressive therapy. Coincidence of the initials of these main drug classes with the first four letters of the alphabet permits an AB/CD rule, according to which recommended combinations are one drug from each of the "AB" and "CD" categories of drugs. However, the diabetogenic potential of the older "B" and "D" classes leads us to advise against combining "B" and "D" in older patients, and to recommend "A" + "C" + "D" as standard triple therapy for resistant hypertension.

Greater inotropic and cyclic AMP responses evoked by noradrenaline through Arg389 beta 1-adrenoceptors versus Gly389 beta 1-adrenoceptors in isolated human atrial myocardium

1. We studied the biochemical and contractile responses of isolated human myocardial tissue expressing native receptor variants of the 389G>R beta(1)-adrenoceptor polymorphism. 2. Right atrial appendage was obtained from homozygous RR patients (n=37) and homozygous GG patients (n=17) undergoing elective cardiac surgery. The positive inotropic effect of noradrenaline in these tissues, mediated through beta(1)-adrenoceptors, was studied using electrically stimulated (1 Hz) atrial strips, as well as the effects of noradrenaline on cyclic AMP levels and cyclic AMP-dependent protein kinase. 3. Tissue from RR homozygotes (n=14) showed significantly increased inotropic potency to noradrenaline (-log EC(50), M=6.92+/-0.12) compared to GG homozygotes (n=8, -log EC(50), M=6.36+/-0.11, P<0.005). This difference was not dependent on tissue basal force. 4. Tissue cyclic AMP levels (pmol mg(-1)) were also greater in RR homozygotes (basal 34.8+/-3.7 n=12, 300 nM noradrenaline 41.4+/-7.6 n=9, 30 micro M noradrenaline 45.2+/-3.2 n=22, 0.2 mM isoprenaline 48.3+/-4.2 n=16) compared to GG homozygotes (basal 30.7+/-4.4 n=5, 300 nM noradrenaline 32.6+/-6.92 n=5, 30 micro M noradrenaline 38.1+/-3.1 n=8, 0.2 mM isoprenaline 42.6+/-5.2 n=6, P=0.007). There were no differences between the variants in terms of cyclic AMP-dependent protein kinase activity. 5. These data provide the first evidence that enhanced G-protein coupling of the R389 beta(1)-adrenoceptor variant reported in rodent fibroblast expression systems is also present in native human receptors. The functional consequence of this is to significantly alter the inotropic potency of beta(1)-adrenoceptor activation depending on its genotype at the 389 position.

Noise exposure and hearing loss among student employees working in university entertainment venues

OBJECTIVES

Most studies to date on sound levels in entertainment establishments have concentrated on exposure levels for the attending public, rather than employees who may be at greater risk of hearing loss. Of particular concern are young employees. The aim of this pilot study was to (i) estimate typical sound levels in different areas where amplified music was played, (ii) measure temporary threshold shift (TTS) and (iii) estimate the dependence of hearing threshold shifts on measured noise levels.

METHODS

This study focused on students working part-time (up to 16 h/week) in music bars and discotheques in a university entertainment venue. All 28 staff were invited to participate in the study. Pre- and post-exposure audiometry was used to determine hearing threshold at both high and low frequencies. Personal dosemeters and static measurements were made to assess noise levels and frequency characteristics. A questionnaire was used to determine patterns of noise exposure and attitudes to noise levels and hearing loss.

RESULTS

Of the 28 student employees working in the three areas, 14 (50%) agreed to take part in the study, giving 21 pre- and post-shift audiograms. The mean personal exposure levels for security staff were higher than those of bar staff, with both groups exceeding 90 dB(A). The maximum peak pressure reading for security staff was 124 dB. Although TTS values were moderate, they were found to be highly significant at both low and high frequencies and for both ears. Twenty-nine per cent of subjects showed permanent hearing loss of more than 30 dB at either low or high frequencies. The correlation between TTS and personal exposure was higher at 4 kHz than the low and high frequencies.

CONCLUSIONS

Contemporary music may be an important yet little considered contributor to total personal noise exposure, especially amongst young employees. Employees need to be better informed of risks of hearing loss and the need to report changes in hearing acuity. Suggestions are made on strategies for improving the assessment of noise exposure in entertainment venues.

Evaluation of land use/land cover datasets for urban watershed modeling

Land use/land cover (LULC) data are a vital component for nonpoint source pollution modeling. Most watershed hydrology and pollutant loading models use, in some capacity, LULC information to generate runoff and pollutant loading estimates. Simple equation methods predict runoff and pollutant loads using runoff coefficients or pollutant export coefficients that are often correlated to LULC type. Complex models use input variables and parameters to represent watershed characteristics and pollutant buildup and washoff rates as a function of LULC type. Whether using simple or complex models an accurate LULC dataset with an appropriate spatial resolution and level of detail is paramount for reliable predictions. The study presented in this paper compared and evaluated several LULC dataset sources for application in urban environmental modeling. The commonly used USGS LULC datasets have coarser spatial resolution and lower levels of classification than other LULC datasets. In addition, the USGS datasets do not accurately represent the land use in areas that have undergone significant land use change during the past two decades. We performed a watershed modeling analysis of three urban catchments in Los Angeles, California, USA to investigate the relative difference in average annual runoff volumes and total suspended solids (TSS) loads when using the USGS LULC dataset versus using a more detailed and current LULC dataset. When the two LULC datasets were aggregated to the same land use categories, the relative differences in predicted average annual runoff volumes and TSS loads from the three catchments were 8 to 14% and 13 to 40%, respectively. The relative differences did not have a predictable relationship with catchment size.

The structure of phosphorylated GSK-3beta complexed with a peptide, FRATtide, that inhibits beta-catenin phosphorylation

BACKGROUND

Glycogen synthase kinase-3 (GSK-3) sequentially phosphorylates four serine residues on glycogen synthase (GS), in the sequence SxxxSxxxSxxx-SxxxS(p), by recognizing and phosphorylating the first serine in the sequence motif SxxxS(P) (where S(p) represents a phosphoserine). FRATtide (a peptide derived from a GSK-3 binding protein) binds to GSK-3 and blocks GSK-3 from interacting with Axin. This inhibits the Axin-dependent phosphorylation of beta-catenin by GSK-3.

RESULTS

Structures of uncomplexed Tyr216 phosphorylated GSK-3beta and of its complex with a peptide and a sulfate ion both show the activation loop adopting a conformation similar to that in the phosphorylated and active forms of the related kinases CDK2 and ERK2. The sulfate ion, adjacent to Val214 on the activation loop, represents the binding site for the phosphoserine residue on 'primed' substrates. The peptide FRATtide forms a helix-turn-helix motif in binding to the C-terminal lobe of the kinase domain; the FRATtide binding site is close to, but does not obstruct, the substrate binding channel of GSK-3. FRATtide (and FRAT1) does not inhibit the activity of GSK-3 toward GS.

CONCLUSIONS

The Axin binding site on GSK-3 presumably overlaps with that for FRATtide; its proximity to the active site explains how Axin may act as a scaffold protein promoting beta-catenin phosphorylation. Tyrosine 216 phosphorylation can induce an active conformation in the activation loop. Pre-phosphorylated substrate peptides can be modeled into the active site of the enzyme, with the P1 residue occupying a pocket partially formed by phosphotyrosine 216 and the P4 phosphoserine occupying the 'primed' binding site.

GSK-3 inhibition by adenoviral FRAT1 overexpression is neuroprotective and induces Tau dephosphorylation and beta-catenin stabilisation without elevation of glycogen synthase activity

Glycogen synthase kinase 3 (GSK-3) has previously been shown to play an important role in the regulation of apoptosis. However, the nature of GSK-3 effector pathways that are relevant to neuroprotection remains poorly defined. Here, we have compared neuroprotection resulting from modulation of GSK-3 activity in PC12 cells using either selective small molecule ATP-competitive GSK-3 inhibitors (SB-216763 and SB-415286), or adenovirus overexpressing frequently rearranged in advanced T-cell lymphomas 1 (FRAT1), a protein proposed as a negative regulator of GSK-3 activity towards Axin and beta-catenin. Our data demonstrate that cellular overexpression of FRAT1 is sufficient to confer neuroprotection and correlates with inhibition of GSK-3 activity towards Tau and beta-catenin, but not modulation of glycogen synthase (GS) activity. By comparison, treatment with SB-216763 and SB-415286 proved more potent in terms of neuroprotection, and correlated with inhibition of GSK-3 activity towards GS in addition to Tau and beta-catenin.

Dietary obesity in the rat induces endothelial dysfunction without causing insulin resistance: a possible role for triacylglycerols

Impaired arterial vasorelaxation, due primarily to endothelial dysfunction, is associated with obesity. To clarify the relationship with insulin resistance and other metabolic disturbances, we studied endothelial-dependent and -independent vascular responses in rats with dietary-induced obesity. Dietary-obese rats had significantly higher body weights (10-32%; P<0.001) and fat-pad masses (220-280%; P<0.001) than lean controls, together with raised plasma levels of triacylglycerols (15-80%; P<0.001), non-esterified fatty acids (13-38%; P<0.05) and leptin (85-180%; P<0.001). However, measures of insulin sensitivity (including the hyperinsulinaemic-euglycaemic clamp in a parallel experiment) were comparable with those in controls. Contractions induced in mesenteric arteries by noradrenaline (0.5-8 micromol/l) were comparable in lean and obese groups, but vasorelaxation in noradrenaline-preconstricted arteries was markedly reduced in dietary-obese rats of both sexes. Concentration-response curves to endothelium-dependent vasorelaxants (acetylcholine, A23187 and insulin) showed significant reductions in maximal relaxation (20-95% less than in leans; P<0.001) and significant rightward shifts in EC(40) (concentration giving 40% of maximal response) (P<0.01). Relaxation in response to the direct NO donor, sodium nitroprusside, showed a lesser impairment (12%; P<0.01) in dietary-obese rats. Maximal relaxation to acetylcholine was correlated inversely in both sexes with fat-pad mass (r(2)=0.37, P<0.05) and plasma triacylglycerols (r(2)=0.51, P<0.01), and with leptin in males only (r(2)=0.35, P<0.05). Independent determinants of acetylcholine-induced relaxation were fat mass and plasma triacylglycerols; plasma insulin and insulin sensitivity had no effect. Dietary-induced obesity severely impaired arterial relaxation in both sexes, particularly at the endothelial level. This is not attributable to insulin resistance, but may be related to moderate hypertriglyceridaemia.

Childhood methanol ingestion treated with fomepizole and hemodialysis

Fomepizole (4-methylpyrazole; Antizol) is used increasingly in the treatment of methanol toxicity in adults. Little experience exists with this drug in the pediatric population, however. We present a case of methanol poisoning in a child in whom the use of fomepizole averted intravenous ethanol infusion and the attendant side effects of this therapy.

Real experiences of uHTS: a prototypic 1536-well fluorescence anisotropy-based uHTS screen and application of well-level quality control procedures

This paper describes, for the first time, a true ultra-high throughput screen (uHTS) based upon fluorescence anisotropy and performed entirely in 1536-well assay plates. The assay is based upon binding and displacement of a BODIPY-FL-labeled antibiotic to a specific binding site on 70S ribosomes from Escherichia coli (Kd approximately 15 nM). The screen was performed at uHTS rates (i.e., >100,000 assay wells/24 h) using entirely commercially available equipment. In order to examine the reproducibility of detection of test compound effects, assays were performed in duplicate. Both overall assay statistics and reproducibility for individual compound results were excellent, at least equivalent to conventional HTS assays. Interference artifacts occurred mainly as a result of autofluorescence from test compounds. Well-level quality control procedures were developed to detect, eliminate, or even correct for such effects. Moreover, development of a brighter, longer wavelength probe (based upon Cy3B) markedly reduced such interferences. Overall, the data demonstrate that fluorescence anisotropy-based uHTS is now a practical reality.