The impact of sedation on the quality of initial skeletal surveys performed for suspected physical abuse in children: a comparative two-centre audit.

BACKGROUND: The impact of sedation on the quality of initial skeletal surveys performed for suspected physical abuse in children is not known. OBJECTIVE: To assess whether sedation influenced the number of, reason for and effective dose of repeat radiographs obtained as part of initial skeletal surveys, and their mean examination times. MATERIALS AND METHODS: One hundred consecutive antemortem initial skeletal survey examinations performed for suspected physical abuse in children <2 years were retrieved from two tertiary paediatric hospitals: Centre 1, where sedation is not used for initial skeletal survey imaging; and Centre 2, where sedation is used routinely. RESULTS: In total, 4055 radiographic projections were performed, of which 93 (2.3%) were repeats. Comparing centres, there was a significant difference in the total number of repeats (P=0.001) and the number of repeats in children aged <12 months (P=0.008). Mean examination times were significantly shorter in unsedated children (P=0.005), even after outliers were excluded (P=0.002). There was no significant difference between the number of routine projections (P=0.587), incompletely imaged body parts (P=0.254), rotation/suboptimal positioning (P=0.527), repeats in children aged >12 months (P=0.089), routine projections in children aged <12 months (P=0.642) or >12 months (P=0.979) or the effective doses of repeats (P=0.286). CONCLUSION: There were fewer repeat projections in sedated children and those aged <12 months but examination times were significantly longer. There was no difference in the effective doses of repeated projections. The routine use of sedation is not supported when performing skeletal survey imaging if the primary considerations are reducing radiation dose and examination time.

Quantitative TMT-based proteomics revealing host, dietary and microbial proteins in bovine faeces including barley serpin Z4, a prominent component in the head of beer.

There has been little information about the proteome of bovine faeces or about the contribution to the faecal proteome of proteins from the host, the feed or the intestinal microbiome. Here, the bovine faecal proteome and the origin of its component proteins was assessed, while also determining the effect of treating barley, the major carbohydrate in the feed, with either ammonia (ATB) or sodium propionate (PTB) preservative. Healthy continental crossbreed steers were allocated to two groups and fed on either of the barley-based diets. Five faecal samples from each group were collected on Day 81 of the trial and analysed by quantitative proteomics using nLC-ESI-MS/MS after tandem mass tag labelling. In total, 281 bovine proteins, 199 barley proteins, 176 bacterial proteins and 190 archaeal proteins were identified in the faeces. Mucosal pentraxin, albumin and digestive enzymes were among bovine proteins identified. Serpin Z4 a protease inhibitor was the most abundant barley protein identified which is also found in barley-based beer, while numerous microbial proteins were identified, many originating bacteria from Clostridium, while Methanobrevibacter was the dominant archaeal genus. Thirty-nine proteins were differentially abundant between groups, the majority being more abundant in the PTB group compared to the ATB group. SIGNIFICANCE: Proteomic examination of faeces is becoming a valuable means to assess the health of the gastro-intestinal tract in several species, but knowledge on the proteins present in bovine faeces is limited. This investigation aimed to characterise the proteome of bovine faecal extracts in order to evaluate the potential for investigations of the proteome as a means to assess the health, disease and welfare of cattle in the future. The investigation was able to identify proteins in bovine faeces that had been (i) produced by the individual cattle, (ii) present in the barley-based feed eaten by the cattle or (iii) produced by bacteria and other microbes in the rumen or intestines. Bovine proteins identified included mucosal pentraxin, serum albumin and a variety of digestive enzymes. Barley proteins found in the faeces included serpin Z4, a protease inhibitor that is also found in beer having survived the brewing process. Bacterial and archaeal proteins in the faecal extracts were related to several pathways related to the metabolism of carbohydrates. The recognition of the range of proteins that can be identified in bovine faeces raises the possibility that non-invasive sample collection of this material could provide a novel diagnostic approach to cattle health and welfare.

Bayesian paternity analysis and mating patterns in a parasitic nematode, Trichostrongylus tenuis.

Mating behaviour is a fundamental aspect of the evolutionary ecology of sexually reproducing species, but one that has been under-researched in parasitic nematodes. We analysed mating behaviour in the parasitic nematode Trichostrongylus tenuis by performing a paternity analysis in a population from a single red grouse host. Paternity of the 150 larval offspring of 25 mothers (sampled from one of the two host caeca) was assigned among 294 candidate fathers (sampled from both caeca). Each candidate father's probability of paternity of each offspring was estimated from 10-locus microsatellite genotypes. Seventy-six (51%) offspring were assigned a father with a probability of >0.8, and the estimated number of unsampled males was 136 (95% credible interval (CI) 77-219). The probability of a male from one caecum fathering an offspring in the other caecum was estimated as 0.024 (95% CI 0.003-0.077), indicating that the junction of the caeca is a strong barrier to dispersal. Levels of promiscuity (defined as the probability of two of an adult's offspring sharing only one parent) were high for both sexes. Variance in male reproductive success was moderately high, possibly because of a combination of random mating and high variance in post-copulatory reproductive success. These results provide the first data on individual mating behaviour among parasitic nematodes.

Emergence of behavioural avoidance strategies of malaria vectors in areas of high LLIN coverage in Tanzania.

Despite significant reductions in malaria transmission across Africa since 2000, progress is stalling. This has been attributed to the development of insecticide resistance and behavioural adaptations in malaria vectors. Whilst insecticide resistance has been widely investigated, there is poorer understanding of the emergence, dynamics and impact of mosquito behavioural adaptations. We conducted a longitudinal investigation of malaria vector host choice over 3 years and resting behaviour over 4 years following a mass long-lasting insecticidal nets (LLINs) distribution in Tanzania. By pairing observations of mosquito ecology with environmental monitoring, we quantified longitudinal shifts in host-choice and resting behaviour that are consistent with adaptation to evade LLINs. The density of An. funestus s.l., declined significantly through time. In tandem, An. arabiensis and An. funestus s.l. exhibited an increased rate of outdoor relative to indoor resting; with An. arabiensis reducing the proportion of blood meals taken from humans in favour of cattle. By accounting for environmental variation, this study detected clear evidence of intra-specific shifts in mosquito behaviour that could be obscured in shorter-term or temporally-coarse surveys. This highlights the importance of mosquito behavioural adaptations to vector control, and the value of longer-term behavioural studies.

Influence of spaceflight on erythrokinetics in man.

A significant postflight reduction in the circulating red cell mass has been observed in both the American and Soviet manned programs. The mechanism and etiology of this loss were studied in blood samples from the four payload crewmen of Spacelab 1 taken before, during, and after flight. These samples and samples from control groups on the ground were analyzed for selected hematological and biochemical parameters, which were chosen on the basis of data previously collected, the restraints imposed by the use of human subjects, and the guidelines established for the first Spacelab mission. Twenty-two hours after weightless exposure, there was an increase in hemoglobin and hematocrit. On day 7 in flight, the hemoglobin and hematocrit remained high and there was a slight decrease in reticulocyte number. On landing, red cell mass, plasma volume, hematocrit, and reticulocyte number were decreased. Throughout the 2-week postflight sampling period, hemoglobin, hematocrit, and reticulocyte number remained below the preflight value. Since this crew was not exposed to 100 percent oxygen these results are viewed as evidence that other spaceflight factors cause the measured red cell mass reduction.

Analysing livestock network data for infectious disease control: an argument for routine data collection in emerging economies.

Livestock movements are an important mechanism of infectious disease transmission. Where these are well recorded, network analysis tools have been used to successfully identify system properties, highlight vulnerabilities to transmission, and inform targeted surveillance and control. Here we highlight the main uses of network properties in understanding livestock disease epidemiology and discuss statistical approaches to infer network characteristics from biased or fragmented datasets. We use a 'hurdle model' approach that predicts (i) the probability of movement and (ii) the number of livestock moved to generate synthetic 'complete' networks of movements between administrative wards, exploiting routinely collected government movement permit data from northern Tanzania. We demonstrate that this model captures a significant amount of the observed variation. Combining the cattle movement network with a spatial between-ward contact layer, we create a multiplex, over which we simulated the spread of 'fast' ( R0 = 3) and 'slow' ( R0 = 1.5) pathogens, and assess the effects of random versus targeted disease control interventions (vaccination and movement ban). The targeted interventions substantially outperform those randomly implemented for both fast and slow pathogens. Our findings provide motivation to encourage routine collection and centralization of movement data to construct representative networks. This article is part of the theme issue 'Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control'. This theme issue is linked with the earlier issue 'Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes'.

Effect of common agonists on cytoplasmic ionized calcium concentration in platelets. Measurement with 2-methyl-6-methoxy 8-nitroquinoline (quin2) and aequorin.

Because of controversy regarding the relationship of cytoplasmic ionized calcium concentration ([Cai2+]) to platelet activation, we studied the correlation of platelet aggregation and ATP secretion with [Cai2+] as determined by 2-methyl-6-methoxy 8-nitroquinoline (quin2) and aequorin in response to ADP, epinephrine, collagen, the Ca2+ ionophore A23187, and thrombin. Both indicators showed a concentration-dependent increase in [Cai2+] in response to all agonists except epinephrine when gel-filtered platelets were suspended in media containing 1 mM Ca2+. With epinephrine, a rise in [Cai2+] was indicated by aequorin, but not by quin2; [Cai2+] signals, aggregation, and secretion were suppressed by EGTA. ADP [0.5 microM] produced a rise in [Cai2+] that was registered by both aequorin and quin2 in platelets in Ca2+-containing media; addition of EGTA to the medium raised the threshold concentration of ADP to 5.0 microM for both indicators. Collagen produced progressive concentration-related increases in [Cai2+] and aggregation in aspirin-treated aequorin-loaded platelets. Quin2 failed to indicate a rise in [Cai2+]at lower collagen concentrations with EGTA or aspirin. [Cai2+] response to A23187 and thrombin was reduced by addition of EGTA to platelets loaded with either aequorin or quin2. With all five agonists in all conditions tested, aequorin [Cai2+] signals occurred at the same agonist concentration as that or lower than that which produced platelet shape change, aggregation, or secretion. Platelet activation was better correlated with changes in [Cai2+] indicated by aequorin than with the response of quin2, possibly because aequorin is more sensitive to local zones of [Cai2+] elevation.

Platelet protein phosphorylation, elevation of cytosolic calcium, and inositol phospholipid breakdown in platelet activation induced by plasmin.

Studies have been performed on the biochemical mechanism of platelet activation induced by the fibrinolytic protease plasmin. In washed human platelets, greater than or equal to 1.0 caseinolytic units (CU/ml plasmin induced aggregation. Platelet [14C]serotonin release was stimulated by 1.0 CU/ml plasmin to an extent comparable to that induced by 1.0 U/ml thrombin. A dose- and time-dependent phosphorylation of the platelet 47,000- and 20,000-kD proteins was noted in 32PO4-labeled platelets incubated with plasmin; phosphorylation was not affected by extracellular Ca2+, but was completely inhibited by an increase in platelet cyclic AMP. Phosphorylation of these platelet proteins suggested that plasmin may act on platelets by stimulating a rise in cytosolic calcium concentration ([Cai2+]) and activating inositol phospholipid-dependent phospholipase C and protein kinase C. Using both quin2 fluorescence and aequorin luminescence as indicators, plasmin was found to elevate platelet [Cai2+] in the presence or absence of extracellular Ca2+. Phospholipase C activation was shown by the generation of [3H]diglyceride in [3H]arachidonic acid-labeled platelets and [32P]phosphatidic acid in 32PO4 labeled platelets exposed to plasmin. Plasmin did not induce formation of thromboxane A2 (TXA2). Only small amounts of this eicosanoid were detected late in the time course after plasmin stimulation. Our results indicate that plasmin causes platelet aggregation and secretion associated with phosphorylation of the 47,000- and 20,000-kD proteins, Ca2+ mobilization, and phospholipase C and protein kinase C activation.

The isolation and characterization of a Norwalk virus-specific cDNA.

Norwalk virus, an important cause of epidemic, acute, nonbacterial gastroenteritis in adults and children, has eluded adaptation to tissue culture, the development of an animal model, and molecular cloning. In this study, a portion of the Norwalk viral genome encoding an immunoreactive region was cloned from very small quantities of infected stool using sequence-independent single primer amplification. Six overlapping complementary DNA (cDNA) clones were isolated by immunologic screening. The expressed recombinant protein from a representative clone reacted with six of seven high titer. Norwalk-specific, postinfection sera but not with corresponding preinfection sera. Nucleic acid sequence for all clones defined a single open reading frame contiguous with the lambda gt11-expressed beta-galactosidase protein. Only oligonucleotide probes specific for the positive strand (defined by the open reading frame) hybridized to an RNaseA-sensitive, DNaseI-resistant nucleic acid sequence extracted from Norwalk-infected stool. Furthermore, RNA extracted from serial postinfection, but not preinfection, stools from three of five volunteers hybridized to a Norwalk virus cDNA probe. Clone-specific oligonucleotide probes hybridized with cesium chloride gradient fractions containing purified Norwalk virion. In conclusion, an antigenic, protein-coding region of the Norwalk virus genome has been identified. This epitope has potential utility in future sero- and molecular epidemiologic studies of Norwalk viral gastroenteritis.

Cytogenetic and flow cytometry DNA analysis of regional heterogeneity in a low grade human glioma.

This study combined flow cytometry with standard cytogenetic analysis of first division cells to evaluate regional heterogeneity in 38 spatially mapped regions of a low grade human oligoastrocytoma. Histologically, the tumor was relatively homogeneous. In contrast, flow cytometry and cytogenetic analyses identified variable percentages of near-diploid (ND; 35 to 57 chromosomes/metaphase) and near-tetraploid (81-103 chromosomes/metaphase) populations. The largest proportion of cells in the ND population was 46,XY with normal Giemsa bands; however, four karyotypically unrelated ND clones also were identified. The development of these clonal populations centered around a region in which more than 50% of the cells contained nonclonal abnormalities and which demonstrated more histological pleomorphism than any other region. The frequency of the nonclonal karyotypes suggested that this region was genetically unstable. Three of the clonal ND populations resided in small, spatially discreet areas of the tumor. The largest and the most widely distributed clonal population, 47,XY,+7, underwent further evolution to give rise to seven additional sidelines. This investigation demonstrates that low grade gliomas have areas of genetic instability capable of generating mutant cells with the capacity to proliferate and to form cellular foci. As a result, multiple, spatially distinct clonal populations can exist in low grade gliomas, some of which are capable of further cytogenetic evolution and clonal expansion, resulting in tumor progression.

Plastic debris in great skua (Stercorarius skua) pellets corresponds to seabird prey species.

Plastic is a common item in marine environments. Studies assessing seabird ingestion of plastics have focused on species that ingest plastics mistaken for prey items. Few studies have examined a scavenger and predatory species that are likely to ingest plastics indirectly through their prey items, such as the great skua (Stercorarius skua). We examined 1034 regurgitated pellets from a great skua colony in the Faroe Islands for plastics and found approximately 6% contained plastics. Pellets containing remains of Northern fulmars (Fulmarus glacialis) had the highest prevalence of plastic. Our findings support previous work showing that Northern fulmars have higher loads of plastics than other sympatric species. This study demonstrates that marine plastic debris is transferred from surface feeding seabird species to predatory great skuas. Examination of plastic ingestion in species that do not ingest plastics directly can provide insights into how plastic particles transfer vertically within the food web.

Statistical modelling studies examining the dimensional structure of psychopathology experienced by adults with intellectual disabilities: Systematic review.

Diagnosing mental ill-health using categorical classification systems has limited validity for clinical practice and research. Dimensions of psychopathology have greater validity than categorical diagnoses in the general population, but dimensional models have not had a significant impact on our understanding of mental ill-health and problem behaviours experienced by adults with intellectual disabilities. This paper systematically reviews the methods and findings from intellectual disabilities studies that use statistical methods to identify dimensions of psychopathology from data collected using structured assessments of psychopathology. The PRISMA framework for systematic review was used to identify studies for inclusion. Study methods were compared to best-practice guidelines on the use of exploratory factor analysis. Data from the 20 studies included suggest that it is possible to use statistical methods to model dimensions of psychopathology experienced by adults with intellectual disabilities. However, none of the studies used methods recommended for the analysis of non-continuous psychopathology data and all 20 studies used statistical methods that produce unstable results that lack reliability. Statistical modelling is a promising methodology to improve our understanding of mental ill-health experienced by adults with intellectual disabilities but future studies should use robust statistical methods to build on the existing evidence base.

Dermal nerves in human diabetic subjects.

The lack of a nerve tissue source that is easily, safely, and repeatedly available has been a major impediment to the study of human diabetic neuropathy. In this study dermal nerves from skin, obtained at biopsy and autopsy from the lower leg and at autopsy from the mid-abdomen, were subjected to quantitative electron microscopy to assess for diabetic perineurial cell basement membrane thickening, a change previously reported in sural nerve. A highly significant degree of perineurial cell basement membrane thickening was found in the diabetic subjects. Other structures in dermal nerves, such as axons, myelin, Schwann cells, and their organelles are also amenable to quantitative ultrastructural study. Skin biopsy is a way to obtain samples of peripheral nervous system tissue safely and repeatedly for the study of diabetic neuropathy.

Comparison of measurement methods for capillary basement membrane thickness. Collapsed-ellipse technique.

Both the grid method of Siperstein et al. (tSIP) and the minimum-points method of Williamson et al. (tWIL) for measurement of capillary basement membrane thickness are inaccurate for assessing mean true membrane thickness of a give section (tTRUE) for various reasons, including errors in selectivity, sensitivity, and geometry. In general, it is agreed that tSIP greater than tTRUE greater than tWIL, but estimates of tTRUE beyond this have not been made. In this study, a collapsed-ellipse method for approximating tTRUE is presented that measures thickness by areas (tEA). One hundred-twenty capillaries from the forearm skin of 12 diabetic subjects and 12 age-matched controls were measured to examine these concepts. We found that, whereas tWIL was up to 63% below tTRUE, tEA was less than 30% too low. Although tSIP, tWIL, and tEA did not distinguish between diabetic and normal subjects, tEA and tWIL measurements had highly predictable and small errors, and tSIP had unpredictable ranges of error, especially when tSIP was low.

Relationships between microvascular function and capillary structure in diabetic and nondiabetic human skin.

Despite the commonly held view that abnormalities in capillary morphology, in particular thickening of the capillary basement membrane, are partly responsible for diabetic ischemia, few studies have correlated anatomic and hemodynamic variables in the same diabetic subjects. In a previous study of 24 type II (non-insulin-dependent) diabetic subjects and 24 age-matched control subjects, we showed that a standard finger exercise vasodilated cutaneous forearm vessels nearly equally (51%), but the postarteriolar flow responded differently between groups. Nondiabetic subjects increased flow by recruitment of capillaries, whereas diabetic subjects did so by capillary flow augmentation. Moreover, resting permeability-surface area product (PS) to pentetic acid was 85% higher in diabetic than nondiabetic subjects. In this study, these same subjects had their forearm skin biopsied and examined morphometrically by electron microscopy for capillary radius, basement membrane thickness, endothelial cell density, and a folding index of luminal membrane reduplication. All morphological variables were correlated stepwise in a saturated, analysis of covariance model with the physiological results. The correlations were sparse and specifically excluded basement membrane thickness. The highest r2 value was .432 between resting PS and a ratio of capillary density to endothelial cell number per capillary. These studies show little evidence that diabetic microvascular physiological variables are tightly connected to morphometric changes except for minor permeability changes, which rise with capillary density and decrease with endothelial cell number. Because PS to pentetic acid is increased in diabetic subjects at any level of capillary density, it seems reasonable that permeability may be increased above that of nondiabetic subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological and molecular analysis of a low-grade recurrence of a glioblastoma multiforme.

We and others have reported that human malignant gliomas demonstrate intratumor heterogeneity in which many regions may be benign; however, the presence of regions of increased malignancy in these same tumors is generally indicative of poor patient prognosis. These data suggested that tumor progression may be a local phenomenon, resulting in regions that progress to a more malignant type prior to the progression of the entire tumor. Implicit in this premise is the idea that molecular markers of tumor progression may be detectable prior to histological evidence of progression. This report details analyses performed on a primary and recurrent tumor obtained from the same patient in which the primary tumor was of a higher histological grade than the recurrent tumor. Results of molecular, cytogenetic, flow cytometric, and histological analyses of the primary tumor were indicative of a grade 4 glioblastoma multiforme. Standard cytogenetic and flow cytometric analyses demonstrated that the cells were near-diploid with a stem line population of 46,XX normal G-banded karyotypes. In contrast, tissue resected from the recurrent tumor 5 months later was histologically less malignant; however, the molecular, cytogenetic, and flow cytometric analyses of this sample demonstrated the presence of specific genetic abnormalities typically found in more malignant tumors. These data demonstrate that specific molecular and/or genetic changes leading to tumor progression may become detectable in a glioma prior to the appearance of histological features of a higher grade tumor.

A cost-effectiveness comparison of the use of antimicrobial agents for treatment or prophylaxis of travelers' diarrhea.

We conducted a decision analysis to compare the cost-effectiveness of antimicrobial agents used for treatment with their use for prophylaxis of travelers' diarrhea. Estimates of the likelihood and the cost of various outcomes were obtained from a panel of experts using the Delphi group opinion technique. Treatment with sulfamethoxazole-trimethoprim for three days was compared with daily prophylaxis with sulfamethoxazole-trimethoprim or doxycycline. The cost-effectiveness of prophylaxis with either agent (75% to 83%) was greater than that of treatment (38%). Treatment would become more cost-effective than prophylaxis when the cumulative risk of acquiring travelers' diarrhea was less than 0.05 episodes per person per week or if the effectiveness of prophylaxis fell below 35% for doxycycline and 46% for sulfamethoxazole-trimethoprim. The most important contributor to the mean cost of travelers' diarrhea in this analysis was the cost associated with a day of incapacitation due to illness. On the basis of the results of this decision analysis, we conclude that prophylaxis of travelers' diarrhea is an option that should be considered for individual situations and recommend further studies of its cost-effectiveness.

A large nontypical outbreak of Norwalk virus. Gastroenteritis associated with exposing celery to nonpotable water and with Citrobacter freundii.

The US Air Force Academy experienced a point-source outbreak of gastroenteritis originally believed to be caused by Salmonella. The overall attack rate was 48% among approximately 3000 cadets and staff. Food-specific attack rates implicated chicken salad. The odds ratio for chicken salad consumption in ill cadets was 10.7 (95% confidence interval: 8.2; 13.8). The celery component had been exposed to nonpotable water. Citrobacter freundii were statistically associated with consumption of the suspected vehicle and subsequent illness. Most aspects were consistent with the epidemiology of Norwalk gastroenteritis. However, the clinical presentation was not typical of reported outbreaks. One hundred five cadets required intravenous rehydration. Serum samples implicated Norwalk virus as the most probable cause of this outbreak. The Centers for Disease Control (Atlanta, Ga) recently began national surveillance for viral gastroenteritis. All outbreaks of gastroenteritis associated with nonpotable water should be investigated for evidence of viral cause.

Microvascular and tissue oxygen distribution.

Understanding of oxygen delivery by the microcirculation has been dominated by the unitary component analysis of Krogh and Erlangen focussed on oxygen transport mediated by single capillaries, oxygenation of tissue as a whole being extrapolated from findings on oxygen exchange in these vessels. This analysis is under revision since capillaries are not sole sources of oxygen. It is increasingly apparent that arterioles are a significant equivalent source, while venules may serve as sinks for capillary and arteriolar oxygen. As a consequence detailed descriptions of the architecture of the microcirculation based on the tissue cylinder conceptualization does not yield new information given the non-exclusive role of capillaries as purveyors of oxygen to tissue. In the present study we investigate how tissue is oxygenated directly from the arteriolar supply on the basis of current results with newly developed optical techniques for the measurement of local intra- and extravascular pO2 by phosphorescence decay. This methodology shows that tissue regions between arterioles and venules have essentially uniform tissue pO2. The only experimentally detectable gradients in pO2 are those present in the immediate vicinity of arterioles. Findings on vascular longitudinal gradients are used to devise a model that links convective and diffusive processes, showing how blood viscosity, blood oxygen-carrying capacity and the slope of the oxygen dissociation curve are linked in determining intravascular and tissue pO2. The integrated approach provides a numerical basis for interpreting consequences of alterations in transport properties of blood applicable to the field of blood substitutes.