STUDIES ON THE SENSITIZATION OF ANIMALS WITH SIMPLE CHEMICAL COMPOUNDS : III. ANAPHYLAXIS INDUCED BY ARSPHENAMINE

Experiments are described which show that with a given treatment guinea pigs can be sensitized to arsphenamine, so that a considerable percentage die in anaphylactic shock on intravenous administration of the substance.

STUDIES ON THE SENSITIZATION OF ANIMALS WITH SIMPLE CHEMICAL COMPOUNDS. II

In continuation of previous work sensitization experiments have been made with various substances such as urushiol, benzyl chlorides, and acyl chlorides. In the case of a series of substituted benzenes (Cl, NO(2)) a connection between sensitizing capacity and lability of the Cl or NO(2) groups has been shown, indicating the formation of conjugated antigens in the animal. This led to the study of benzyl and acyl chlorides which, actually, were found to have sensitizing capacity. Most informative as to the relationship between reactions of the skin surface and anaphylaxis were experiments with acyl chlorides. Guinea pigs sensitized with p-chlorobenzoyl chloride showed, on the one hand, the usual surface lesions after application of the substance, and on the other typical anaphylactic shock following intravenous injection of a compound of p-chlorobenzoyl chloride and guinea pig serum; from which it may be inferred that the two types of allergic manifestation are closely related conditions.

How heritable is innate behaviour?

The relations between innateness and heritability of behaviour, environmental heterogeneity, genetic diversity of populations, and rates of evolution of behaviour are discussed on the basis of a simple quantitative model. An index I of innateness is proposed which can be related to the heritability index h2. I and h2 are positively related but the degree of correlation depends on the genetic variability of the population, the heterogeneity of the conditioning environment, and the level of spontaneous behavioural variability. The influence of innateness on rates of evolution is moderate. The frequency distributions of I and h2 are unimodal, there is no evidence for an innate-acquired dichotomy.

Simulation of 3D objects into breast tomosynthesis images

Digital breast tomosynthesis is a new three-dimensional (3D) breast-imaging modality that produces images of cross-sectional planes parallel to the detector plane from a limited number of X-ray projections over a limited angular range. Several technical and clinical parameters have not yet been completely optimised. Some of the open questions could be addressed experimentally; other parameter settings cannot be easily realised in practice and the associated optimisation process requires therefore a theoretical approach. Rather than simulating the complete 3D imaging chain, it is hypothesised that the simulation of small lesions into clinical (or test object) images can be of help in the optimisation process. In the present study, small 3D objects have been simulated into real projection images. Subsequently, these hybrid projection images are reconstructed using the routine clinical reconstruction tools. In this study, the validation of this simulation framework is reported through the comparison between simulated and real objects in reconstructed planes. The results confirm that there is no statistically significant difference between the simulated and the real objects. This suggests that other small mathematical or physiological objects could be simulated with the same approach.

The partial coherence method for assessment of impaired cerebral autoregulation using near-infrared spectroscopy: potential and limitations

The most important forms of brain injury in premature infants are partly caused by disturbances in cerebral autoregulation. As changes in cerebral intravascular oxygenation (HbD), regional cerebral oxygen saturation (rSO(2)), and cerebral tissue oxygenation (TOI) reflect changes in cerebral blood flow (CBF), impaired autoregulation can be measured by studying the concordance between HbD/rSO(2)/TOI and the mean arterial blood pressure (MABP), assuming no changes in oxygen consumption, arterial oxygen saturation (SaO(2)), and in blood volume. We investigated the performance of the partial coherence (PCOH) method, and compared it with the coherence method (COH). The PCOH method allows the elimination of the influence of SaO(2) on HbD/rSO(2)/TOI in a linear way. We started from long-term recordings measured in the first days of life simultaneously in 30 infants from three medical centres. We then compared the COH and PCOH results with patient clinical characteristics and outcomes, and concluded that PCOH might be a better method for assessing impaired autoregulation.

Unenhanced brain CT is useful to decide on further imaging in suspected venous sinus thrombosis

AIM

To assess the value of unenhanced brain computed tomography (CT) in the diagnosis of cerebral venous sinus thrombosis (CVST).

MATERIALS AND METHODS

Unenhanced brain CT images of 26 patients with proven CVST were mixed with 26 age and sex-matched images from patients without CVST. Four readers reviewed the 52 brain CT images and were asked to score the examinations for the absence or presence of CVST on a scale from 0 to 4. The mean density in the different venous sinuses was measured by one radiologist.

RESULTS

The sensitivity of unenhanced brain CT for the diagnosis of CVST was 73%. There were no false-positive readings. A receiver-operating characteristic (ROC) analysis on these data resulted in an area under the curve of 0.86. Density measurements proved to be helpful, but could not detect all cases of CVST.

CONCLUSION

Unenhanced brain CT is a valid initial radiological examination in the diagnosis of CVST. Due to the absence of false-positives in the present series, unenhanced CT can be used to decide whether further imaging with CT angiography or magnetic resonance angiography is required.

Prevalence and risk factors for stunting and severe stunting among under-fives in North Maluku province of Indonesia

BACKGROUND

Adequate nutrition is needed to ensure optimum growth and development of infants and young children. Understanding of the risk factors for stunting and severe stunting among children aged less than five years in North Maluku province is important to guide Indonesian government public health planners to develop nutrition programs and interventions in a post conflict area. The purpose of the current study was to assess the prevalence of and the risk factors associated with stunting and severe stunting among children aged less than five years in North Maluku province of Indonesia.

METHODS

The health and nutritional status of children aged less than five years was assessed in North Maluku province of Indonesia in 2004 using a cross-sectional multi-stage survey conducted on 750 households from each of the four island groups in North Maluku province. A total of 2168 children aged 0-59 months were used in the analysis.

RESULTS

Prevalence of stunting and severe stunting were 29% (95%CI: 26.0-32.2) and 14.1% (95%CI: 11.7-17.0) for children aged 0-23 months and 38.4% (95%CI: 35.9-41.0) and 18.4% (95%CI: 16.1-20.9) for children aged 0-59 months, respectively. After controlling for potential confounders, multivariate analysis revealed that the risk factors for stunted children were child's age in months, male sex and number of family meals per day (<or=2 times), for children aged 0-23 months, and income (poorest and middle-class family), child's age in months and male sex for children aged 0-59 months. The risk factors for severe stunting in children aged 0-23 months were income (poorest family), male sex and child's age in months and for children aged 0-59 months were income (poorest family), father's occupation (not working), male sex and child's age in months.

CONCLUSION

Programmes aimed at improving stunting in North Maluku province of Indonesia should focus on children under two years of age, of male sex and from families of low socioeconomic status.

A new interspecific, Gossypium hirsutum x G. barbadense, RIL population: towards a unified consensus linkage map of tetraploid cotton

We report the development of a new interspecific cotton recombinant inbred line (RIL) population of 140 lines deriving from an interspecific cross between Gossypium hirsutum (Gh) and G. barbadense (Gb), using the same two parents that have served for the construction of a BC(1) map and for the marker-assisted backcross selection program underway at CIRAD. Two marker systems, microsatellites and AFLPs, were used. An important feature of the RIL population was its marked segregation distortion with a genome-wide bias to Gh alleles (parental genome ratio is 71/29). The RIL map displays an excellent colinearity with the BC(1) map, although it is severely contracted in terms of map size. Existence of 255 loci in common (between 6 and 14 per chromosome) allowed the integration of the two data sets. A consensus BC(1)-RIL map based upon 215 individuals (75 BC1 + 140 RIL) was built. It consisted of 1,745 loci, spanned 3,637 cM, intermediate between the sizes of the two component maps, and constituted a solid framework to cross align cotton maps using common markers. The new RIL population will be further exploited for fiber property QTL mapping and eQTL mapping.

Antibiotic resistance among bacterial pathogens in Central Africa: a review of the published literature between 1955 and 2008

A systematic review of the published literature on bacterial resistance in Central Africa between 1955 and 2008 was performed. Eighty-three publications from seven countries were retrieved, the majority presenting data on enteric and other gram-negative pathogens. Despite methodological limitations in many studies, alarming resistance rates are noted in nearly all pathogens. Of special concern are multidrug resistance in Shigella and Salmonella spp. and the emergence of meticillin-resistant Staphylococcus aureus, high-level penicillin-resistant Streptococcus pneumoniae and extended-spectrum beta-lactamases among gram-negative pathogens. These findings make clear that the Central African region shares the worldwide trend of increasing antimicrobial resistance and is in urgent need of sound surveillance based on competent and affordable microbiology to provide clear data on antimicrobial resistance. These data could enable redaction of local treatment guidelines and fuel national and regional policies to contain antimicrobial resistance.

High-frequency oscillations mirror disease activity in patients with epilepsy

OBJECTIVE

High-frequency oscillations (HFOs) can be recorded in epileptic patients with clinical intracranial EEG. HFOs have been associated with seizure genesis because they occur in the seizure focus and during seizure onset. HFOs are also found interictally, partly co-occurring with epileptic spikes. We studied how HFOs are influenced by antiepileptic medication and seizure occurrence, to improve understanding of the pathophysiology and clinical meaning of HFOs.

METHODS

Intracerebral depth EEG was partly sampled at 2,000 Hz in 42 patients with intractable focal epilepsy. Patients with five or more usable nights of recording were selected. A sample of slow-wave sleep from each night was analyzed, and HFOs (ripples: 80-250 Hz, fast ripples: 250-500 Hz) and spikes were identified on all artifact-free channels. The HFOs and spikes were compared before and after seizures with stable medication dose and during medication reduction with no intervening seizures.

RESULTS

Twelve patients with five to eight nights were included. After seizures, there was an increase in spikes, whereas HFO rates remained the same. Medication reduction was followed by an increase in HFO rates and mean duration.

CONCLUSIONS

Contrary to spikes, high-frequency oscillations (HFOs) do not increase after seizures, but do so after medication reduction, similarly to seizures. This implies that spikes and HFOs have different pathophysiologic mechanisms and that HFOs are more tightly linked to seizures than spikes. HFOs seem to play an important role in seizure genesis and can be a useful clinical marker for disease activity.

Effect of Flavobacterium columnare inoculation, antibiotic treatments and resident bacteria on rainbow trout Oncorhynchus mykiss eyed egg survival and external membrane structure

This study was conducted to evaluate the potential pathogenicity of the bacterium Flavobacterium columnare on rainbow trout Oncorhynchus mykiss eyed eggs. Survival to hatching was unaffected by the inclusion in the incubation water of either 300 colony-forming units (CFU) ml(-1) or 3000 CFU ml(-1) of F. columnare at either 10 or 12 degrees C in either McConaughy or Shasta strain eyed eggs. Bacterial numbers, obtained via scanning electron microscopy or culture, and external membrane morphology were also not significantly different among eggs receiving different concentrations of F. columnare. Initial F. columnare burdens were significantly and positively correlated to the presence of biofilm on the egg external membrane, and biofilm was in turn significantly correlated with increased membrane degradation. The use of either streptomycin or tetracyclin antibiotics significantly reduced bacterial numbers on McConaughy strain eggs, and more eggs survived to hatch in those dishes treated with antibiotics.

Lumped flow modeling in dynamically loaded coronary vessels

Most of the myriad (order of 10(9)) interconnected coronary vessels interact nonlinearly with their embedding contracting myocardium. Their dynamic flow can be simulated based on a nonlinear distributive segmental flow model involving highly nonlinear partial differential equations. Such network flow analysis, although of high accuracy, is computationally excessively complex. On the other hand, a corresponding nonlinear lumped analysis is significantly less demanding since it involves ordinary differential equations. This is, however, at the detriment of accuracy. In the present technical report, a nonlinear lumped representation of coronary segmental flow is presented and tested against predictions of the corresponding distributive analysis. The results suggest that under physiological conditions, the proposed lumped model achieves similar accuracy to the distributive one, yet with considerably higher computational speed.

First come, first serve: "sit and wait" behavior in dung beetles at the source of primate dung

Dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) compete intensively for dung resources, and most species forage in the understory. Here, we describe the unique behavior of one dung beetle species, Canthon aff. quadriguttatus (Olivier), associated with two species of monkeys from Peru. We observed this beetle species on the genital and anal regions of the brown titi monkey, Callicebus brunneus (Wagner), and subsequently falling with dung as the monkeys defecated. The same association was also observed with the bald-faced saki monkey, Pithecia irrorata irrorata (Gray). Using the ' sit and wait' at the source behavior, C. quadriguttus may arrive first at the dung resource, possibly out-competing other dung beetle species. This paper is the first report of this behavior for C. aff. quadriguttatus on the brown titi monkey and bald-faced saki monkey from southeastern, Amazonian Peru. We discuss this behavior in the context of competition and resource partitioning, and also speculate as to why C. aff. quadriguttatus has been found on both monkey species.

Artifacts in digital mammography

In April 2005 screening with digital mammography was allowed in the Flemish part of Belgium. A rigorous physical-technical Quality Control (QC) procedure based on the European guidelines (EUREF) was then implemented. Besides quality control, there is also quality assurance (QA). Detection of artifacts is part of the QA. During the central second reading, a continuous evaluation of the image quality is done. All visible artifacts in the digital images are registered and collected. All systems participate also in a daily quality control, with a daily exposure of a phantom image which is sent to the certified quality control group. The collected artifacts were divided into 5 different categories: patient related artifacts, technologist related artifacts, mammography unit related artifacts, processing related artifacts and viewing conditions related artifacts. Patient related artifacts are comparable with film screen mammography (FSM) and are therefore not discussed. One of the main artifacts in the group of technologist related artifacts is dust in the cassette of computed radiography (CR) systems. In the group of mammography unit related artifacts a distinction is made between the artifacts of CR systems and direct radiography (DR) systems. In the CR group, the artifacts originate in the reader, whereas in the DR group they originate in the detector, which in our study was a Selenium detector. Artifacts due to failure of the Selenium detector are most frequent in this last group. Processing related artifacts are found when the reading of the processing algorithm by the system or by the PACS software made mistakes. Because there is a daily quality control of the monitors of the soft copy work stations, we didn't recognize viewing conditions related artifacts. Some of the artifacts can simulate breast lesions or can disturb the reading of the images. In order to avoid misinterpretation, recognizing artifacts and understanding their physical-technical background are of great importance in digital breast imaging.

Results of a European dose survey for mammography

For the dose study, a semi-automated method of data collection is used in this study. The participating centres were asked to fill out a spreadsheet with all necessary data and return it. For direct digital (DR) systems, the relevant data available in the DICOM header were used. All data is automatically added to a database and processed. The data were used to calculate the mean glandular dose for every image and for different thicknesses of polymethyl methacrylate phantoms using available conversion factors. Second-degree polynomials were fitted to the patient dose data and a reference dose curve was constructed for a range of thicknesses instead of a dose reference level at a single point. The dose reference curve rises from 1.57 mGy for a thickness of 30 mm to 2.50 mGy for 55 mm and 3.83 mGy for 75 mm. The results show centres that exceed this curve lie only in the lower or higher range of thicknesses and would remain undetected using a dose reference value in a single point. This gives better information to radiographers on where there is room for improvement of the dose levels in their system.

A quantitative method for evaluating the detectability of lesions in digital mammography

This study presents a quantitative method for evaluating the detectability of microcalcifications in digital mammography. Four hundred and twenty microcalcifications (with various morphology, size and contrast), simulated with a previously validated method, were used for the creation of image datasets. Lesions were inserted into 163 regions of interests of 59 selected raw digital mammograms with various anatomical backgrounds and acquired with a Siemens Novation DR. After processing, these composite images were scored by experienced radiologists, who located multiple simulated lesions and rated them under conditions of free-search. For statistical analysis, free-response receiver-operating characteristic curves are plotted; the use of jackknife free-response receiver-operating characteristic method has also been investigated. The main advantage of this methodology is that the exact number of inserted microcalcifications is well known and that the lesions are fully characterised in terms of pathology, size, morphology and peak contrast. A first application has been the evaluation of the effect of anatomical background on microcalcifications detection. Preliminary findings in this study indicate that this method may be a promising tool to evaluate factors that have an influence on the detectability of lesions, such as the clinical processing or the viewing conditions.