Tools for opening new chapters in the book of Treponema pallidum evolutionary history

Treponema pallidum infections causing yaws disease and venereal syphilis are globally widespread in human populations, infecting hundreds of thousands and millions annually respectively; endemic syphilis is much less common, and pinta has not been observed in decades. We discuss controversy surrounding the origin, evolution and history of these pathogens in light of available molecular and anthropological evidence. These bacteria (or close relatives) seem to affect many wild African nonhuman primate (NHP) species, though to date only a single NHP Treponema pallidum genome has been published, hindering detection of spillover events and our understanding of potential wildlife reservoirs. Similarly, only ten genomes of Treponema pallidum infecting humans have been published, impeding a full understanding of their diversity and evolutionary history. Research efforts have been hampered by the difficulty of culturing and propagating Treponema pallidum. Here we highlight avenues of research recently opened by the coupling of hybridization capture and next-generation sequencing. We present data generated with such an approach suggesting that asymptomatic bones from NHP occasionally contain enough treponemal DNA to recover large fractions of their genomes. We expect that these methods, which naturally can be applied to modern biopsy samples and ancient human bones, will soon considerably improve our understanding of these enigmatic pathogens and lay rest to old yet unresolved controversies.

The association between metabolic syndrome and pressure ulcers among individuals living with spinal cord injury

OBJECTIVE

The objective of this study was to identify the relationship between metabolic syndrome (MetS) and pressure ulcers (PrU), after controlling for demographic and injury characteristics, socioeconomic factors, health behaviors and fatigue among participants with spinal cord injury (SCI).

METHODS

This cross-sectional study recruited 350 participants with SCI from a hospital in the western region of the USA. Blood tests and physical examination were performed. Waist circumference, high-density cholesterol, triglycerides, blood pressure and fasting glucose were used to diagnose MetS according to Criteria for Clinical Diagnosis of Metabolic Syndrome defined by the American Heart Association. All other variables were self-reported. Three-stage multivariate logistic regression models were conducted to evaluate the effects of three sequential sets of predictors, including demographic/injury, socio-environmental/behavioral and health factors, basing the order of analysis on the Theoretical Risk and Prevention Model.

RESULTS

The prevalence of PrU and MetS was 11.0% (n=36) and 35.3% (n=115), respectively. Ethnicity, smoking, alcohol consumption and MetS were statistically associated with PrU in the full model. Participants who were non-Hispanic (odds ratio (OR)=10.30, 95% confidence interval (CI): 3.46-30.65), smokers (OR=2.69, 95% CI: 1.00-7.27) and drank over 30 drinks per month (OR=5.26, 95% CI: 1.24-22.26) had greater odds of having a PrU compared with those who were Hispanic, non-smokers and non-drinkers, respectively. We also observed a positive association between MetS and PrU (OR_MetS=3.71, 95% CI: 1.45-9.52), even after controlling for all other factors.

CONCLUSION

Participants who had MetS had higher odds of PrU than those without MetS after adjusting for multiple covariates. Unhealthy behaviors such as smoking and excess drinking were positively associated with PrU.

Crimson Spotted Rainbowfish (Melanotaenia duboulayi) Change Their Spatial Position according to Nutritional Requirement

Decision making in moving animal groups has been shown to be disproportionately influenced by individuals at the front of groups. Therefore, an explanation of state-dependent positioning of individuals within animal groups may provide a mechanism for group movement decisions. Nutritional state is dynamic and can differ between members of the same group. It is also known to drive animal movement decisions. Therefore, we assayed 6 groups of 8 rainbowfish foraging in a flow tank. Half of the fish had been starved for 24h and half had been fed 1h prior to experimental start. Groups were assayed again one week later but individuals were allocated to the opposite nutritional treatment. During the assay the positions of individually identified fish were recorded as were the number of food items they each ate and the position within the group they acquired them from. Food-deprived fish were more often found towards the front of the shoal; the mean weighted positional score of food-deprived fish was significantly larger than that of well-fed fish. Individuals were not consistent in their position within a shoal between treatments. There was a significant positive correlation between mean weighted positional score and number of food items acquired which displays an obvious benefit to front positions. These results suggest that positional preferences are based on nutritional state and provide a mechanism for state-dependent influence on group decision-making as well as increasing our understanding of what factors are important for group functioning.

Enzymatic hydrolysis in an aqueous organic two-phase system using centrifugal partition chromatography

Multi-phase reaction systems, mostly aqueous organic systems, are used in enzyme catalysis to convert hydrophobic substrates which are almost insoluble in aqueous media. In this study, a Centrifugal Partition Chromatograph is used as a compact device for enzymatic multi-phase reaction that combines efficient substrate supply to the aqueous phase and separation of both phases in one apparatus. A process design procedure to systematically select the aqueous and organic phase to achieve stable and efficient reaction rates and operation conditions in Centrifugal Partition Chromatography for efficient mixing and separation of the phases is presented. The procedure is applied to the hydrolysis of 4-nitrophenyl palmitate with a lipase derived from Candida rugosa. It was found that the hydrolysis rate of 4-nitrophenyl palmitate was two times higher in Centrifugal Partition Chromatography than in comparable stirred tank reactor experiments.

Massenspektrometrische Bestimmung von Bindungsenergien in siliciumorganischen Verbindungen / Mass-spectrometric Determination of Bond Dissoziation Energies in Organosilicon Compounds

The appearance potentials for a large number of organosilicon ions have been measured. Combination of these values with thermochemical heats of combustion allow the determination of bond energy terms which may be used to calculate heats of formation for all silicon compounds containing hydrogen, alkyl and chlorine ligands. The bond dissoziation energies D(Si - H)= 89 ± 4, D(Si - C) = 85 ± 4 and D (Si - Si) =75 ± 8 kcal/Mol were found to be independent of the number of methylgroups attached to silicon. In addition the Si - Cl bond energy was found to be 116 and 104 kcal/Mol in (CH3)3SiCl and Cl3SiCl respectively.

[Controversies of partial nephrectomy for renal cell carcinoma : survey in the German-speaking countries]

BACKGROUND

The goal of this study was to evaluate how partial nephrectomy is technically performed in Germany, Austria, and Switzerland.

METHODS

A one-page anonymous questionnaire was designed to evaluate the indication, the technical procedure, and the follow-up of R1 situation after partial nephrectomy. Furthermore, the size of the hospitals and their catchment areas were recorded. The questionnaire was sent to 341 clinics and a statistical analysis was performed.

RESULTS

The response rate was 69 %. Up to 99 % of the clinics also perform partial resection in T1b tumors. Of those responding, 58 % perform this surgery laparoscopically, and 83 % of the surgeries are performed in warm ischemia. For the follow-up, 29 % suggest imaging within the first 6 weeks. According to this survey, maximum care clinics perform laparoscopic nephrectomy more frequently (p = 0.003).

CONCLUSION

The survey of 236 hospitals performing partial nephrectomy shows great variability in the indication, technique, and aftercare of organ-preserving renal tumor surgery. It also shows that a large proportion of tumors >4 cm undergo organ-preserving surgery, many of them minimally invasive. The diverse handling with positive instantaneous section and R1 results suggest the need for further studies concerning long-term follow-up after minimally invasive surgery with R1 situation and renal tumors > T1a.

How sailfish use their bills to capture schooling prey

The istiophorid family of billfishes is characterized by an extended rostrum or 'bill'. While various functions (e.g. foraging and hydrodynamic benefits) have been proposed for this structure, until now no study has directly investigated the mechanisms by which billfishes use their rostrum to feed on prey. Here, we present the first unequivocal evidence of how the bill is used by Atlantic sailfish (Istiophorus albicans) to attack schooling sardines in the open ocean. Using high-speed video-analysis, we show that (i) sailfish manage to insert their bill into sardine schools without eliciting an evasive response and (ii) subsequently use their bill to either tap on individual prey targets or to slash through the school with powerful lateral motions characterized by one of the highest accelerations ever recorded in an aquatic vertebrate. Our results demonstrate that the combination of stealth and rapid motion make the sailfish bill an extremely effective feeding adaptation for capturing schooling prey.

The role of individuality in collective group movement

How different levels of biological organization interact to shape each other's function is a central question in biology. One particularly important topic in this context is how individuals' variation in behaviour shapes group-level characteristics. We investigated how fish that express different locomotory behaviour in an asocial context move collectively when in groups. First, we established that individual fish have characteristic, repeatable locomotion behaviours (i.e. median speeds, variance in speeds and median turning speeds) when tested on their own. When tested in groups of two, four or eight fish, we found individuals partly maintained their asocial median speed and median turning speed preferences, while their variance in speed preference was lost. The strength of this individuality decreased as group size increased, with individuals conforming to the speed of the group, while also decreasing the variability in their own speed. Further, individuals adopted movement characteristics that were dependent on what group size they were in. This study therefore shows the influence of social context on individual behaviour. If the results found here can be generalized across species and contexts, then although individuality is not entirely lost in groups, social conformity and group-size-dependent effects drive how individuals will adjust their behaviour in groups.

Angiofibroma: a flow cytometric evaluation of 31 cases

Angiofibromas are histologically benign but locally aggressive tumors that often extend beyond the nasopharynx to involve contiguous structures. In addition, attempts to remove the tumors surgically are often frustrated by local recurrences. We studied 31 angiofibromas by flow cytometry to determine if tumor ploidy could be used to identify those tumors that might behave more aggressively. The patients, all males between 5 and 23 years of age, were divided into two groups. The 21 patients with tumors confined to the nasopharynx or paranasal sinuses were regarded as having local disease, the ten with tumors involving the infratemporal fossa, orbit, cheek, or intracranial structures were regarded as having extensive disease. Of the ten with extensive disease, six bad intracranial involvement. All patients were treated with surgery and only one received postoperative irradiation. Follow-up was available in 24, eight of which developed local recurrences (33%). All tumors, including recurrences and those with intracranial extension, were found to be diploid. We therefore conclude that tumor ploidy cannot be used to predict the clinical course of angiofibromas.

[Smokers develop a nasal obstruction in supine position]

BACKGROUND

We found in a previous study a healthy non-smoker nose does not develop obstruction lying in supine position . We examined whether a designated smoker nose behaves consistently.

MATERIAL AND METHODS

39 healthy young smokers participated. The daily consumption was Ø 21 cigarettes. 9 test positions have been realized. Acoustic rhinometry was used for the estimation of nasal volumes and the nasal minimum cross-sectional areas as parameters for nasal respiration. Additionally, blood pressure and heart rate were measured to control the cardiovascular behavior.

RESULTS

The total nasal volume decreased significantly lying down. Only one third of the volunteers noticed this obstruction. Going upstairs all measured parameters increased. 2 min later all rhinometric parameters, the diastolic blood pressure and heart rate had reached its baseline level. Systolic blood pressure took about 4 min.

CONCLUSIONS

A cigarette smoke-induced nasal obstruction can be demonstrated during supine position using the acoustic rhinometry. One third of smokers noted a deterioration of nasal breathing. During stairs climbing the sympathic tone is increasing followed by nasal decongestion, raised blood pressure and heart rate. If smokers complaint of nasal obstruction in lying position - whether alert or during sleep - it is advisable to lift the bed-head. In medium term a therapy of chronic rhinitis with topical corticosteroids, in longer term a smoking cessation is recommended.

Personality in the context of social networks

There is great interest in environmental effects on the development and evolution of animal personality traits. An important component of an individual's environment is its social environment. However, few studies look beyond dyadic relationships and try to place the personality of individuals in the context of a social network. Social network analysis provides us with many new metrics to characterize the social fine-structure of populations and, therefore, with an opportunity to gain an understanding of the role that different personalities play in groups, communities and populations regarding information or disease transmission or in terms of cooperation and policing of social conflicts. The network position of an individual is largely a consequence of its interactive strategies. However, the network position can also shape an individual's experiences (especially in the case of juveniles) and therefore can influence the way in which it interacts with others in future. Finally, over evolutionary time, the social fine-structure of animal populations (as quantified by social network analysis) can have important consequences for the evolution of personalities-an approach that goes beyond the conventional game-theoretic analyses that assumed random mixing of individuals in populations.

[Digital volume tomography (DVT) and multislice spiral CT (MSCT): an objective examination of dose and image quality]

PURPOSE

In the last five years digital volume tomographs (DVT) have found their way into the diagnostic imaging of the facial skull. In this study both the image quality and dose of DVT and multislice spiral CT (MSCT) in this field of application were investigated using established physical methods for CT.

MATERIALS AND METHODS

Measurements on DVT scanners of various manufacturers and on a modern MSCT scanner were performed. The investigation was based on equivalent dose levels for both modalities (CT dose index, CTDI). For this purpose, the dose was measured with an ionization chamber in a cylindrical PMMA phantom. For the evaluation of image quality, the spatial resolution, contrast and noise were investigated with phantoms established for CT.

RESULTS

MSCT exhibited spatial resolution values of 1.0 to 1.6 lp/mm, while DVT provided resolution between 0.6 and 1.0 lp/mm only. Thus, MSCT offered similar or better resolution at an equivalent dose. For soft tissue resolution, DVT showed significant image artifacts. MSCT yielded higher homogeneity and no significant artifacts, and the contrast steps of the phantom were more verifiable. The different DVT devices, from image intensifiers to modern flat-detector (FD) devices, showed significant differences in favor of the FD devices.

CONCLUSION

For medium and high contrast applications (teeth/bones), DVT scanners can be an alternative to MSCT at comparable radiation exposure. However, MSCT offers advantages in terms of constantly good and controlled image quality with significantly more flexible scan parameters at a constant or lower dose and should therefore be given preference.

Social network theory in the behavioural sciences: potential applications

Social network theory has made major contributions to our understanding of human social organisation but has found relatively little application in the field of animal behaviour. In this review, we identify several broad research areas where the networks approach could greatly enhance our understanding of social patterns and processes in animals. The network theory provides a quantitative framework that can be used to characterise social structure both at the level of the individual and the population. These novel quantitative variables may provide a new tool in addressing key questions in behavioural ecology particularly in relation to the evolution of social organisation and the impact of social structure on evolutionary processes. For example, network measures could be used to compare social networks of different species or populations making full use of the comparative approach. However, the networks approach can in principle go beyond identifying structural patterns and also can help with the understanding of processes within animal populations such as disease transmission and information transfer. Finally, understanding the pattern of interactions in the network (i.e. who is connected to whom) can also shed some light on the evolution of behavioural strategies.

The effects of different predator species on antipredator behavior in the Trinidadian guppy, Poecilia reticulata

Different types of predators often elicit different antipredator responses in a common type of prey. Alternatively, some prey species may adopt a general response, which provides limited protection from many different types of predator. The Trinidadian guppy, Poecilia reticulata, is faced with a wide range of different predators throughout its range and is known to display varying levels of antipredator behavior depending on the predator assemblage. Pike cichlids, Crenicichla frenata, are regarded as the primary aquatic guppy predator in streams in the northern mountain range in Trinidad. As such, they are seen to be responsible for many of the differences in morphology, life history traits, and behavior between guppy populations from areas with few predators and those from areas with many pike cichlids. In this study we investigated how guppies responded when faced with different predator species using three common aquatic predators. We exposed shoals of ten guppies to one out of four treatments: no predator (control), pike cichlid, acara cichlid (Aequidens pulcher), and wolf fish (Hoplias malabaricus); and we made behavioral observations on both focal individuals and the shoal as a whole. Guppies showed significantly greater levels of predator inspection and shoaling behavior, foraged less, spent more time in the surface water, and stayed in significantly larger shoals when faced with pike cichlids than in other treatments. We discuss these results in the context of multiple predator effects.

Assortative interactions and social networks in fish

The mechanisms underpinning the structure of social networks in multiple fish populations were investigated. To our knowledge this is the first study to provide replication of social networks and therefore probably the first that allows general conclusions to be drawn. The social networks were all found to have a non-random structure and exhibited 'social cliquishness'. A number of factors were observed to contribute to this structuring. Firstly, social network structure was influenced by body length and shoaling tendency, with individuals interacting more frequently with conspecifics of similar body length and shoaling tendency. Secondly, individuals with many social contacts were found to interact with each other more often than with other conspecifics, a phenomenon known as a 'positive degree correlation'. Finally, repeated interactions between pairs of individuals occurred within the networks more often than expected by random interactions. The observed network structures will have ecological and evolutionary implications. For example, the occurrence of positive degree correlations suggests the possibility that pathogens and information (that are socially transmitted) could spread very fast within the populations. Furthermore, the occurrence of repeated interactions between pairs of individuals fulfils an important pre-requisite for the evolution of reciprocal altruism.

Geometry for mutualistic and selfish herds: the limited domain of danger

We present a two-dimensional individual-based model of aggregation behaviour in animals by introducing the concept of a "limited domain of danger", which represents either a limited detection range or a limited attack range of predators. The limited domain of danger provides a suitable framework for the analysis of individual movement rules under real-life conditions because it takes into account the predator's prey detection and capture abilities. For the first time, a single geometrical construct can be used to analyse the predation risk of both peripheral and central individuals in a group. Furthermore, our model provides a conceptual framework that can be equally applied to aggregation behaviour and refuge use and thus presents a conceptual advance on current theory that treats these antipredator behaviours separately. An analysis of individual movement rules using limited domains of danger showed that the time minimization strategy outcompetes the nearest neighbour strategy proposed by Hamilton's (J. Theor. Biol. 31 (1971) 295) selfish herd model, whereas a random strategy confers no benefit and can even be disadvantageous. The superior performance of the time minimization strategy highlights the importance of taking biological constraints, such as an animal's orientation relative to its neighbours, into account when searching for efficient movement rules underlying the aggregation process.

Changes in hemorheological and biochemical parameters following short-term and long-term smoking cessation induced by nicotine replacement therapy (NRT)

OBJECTIVES

Cigarette smoking causes cardiovascular (CV) disease, but the relative roles of nicotine and other components of tobacco smoke remain unclear. We investigated the effect of stopping smoking by using nicotine replacement therapy (NRT) on hemorheology parameters, on the cotinine and thiocyanate plasma concentrations and the exhaled carbon monoxide (CO).

DESIGN

Open, parallel-group trial (intervention group and control smokers).

SUBJECTS

197 males, aged 25-45 years, smoking > 20 cigarettes per day (cpd).

INTERVENTIONS

164 subjects were instructed to stop smoking and received NRT for 12 weeks and 33 acted as controls. After 12 weeks, NRT was discontinued and all subjects were followed-up at 26 weeks. Beginning with week 4, the treated subjects were divided into abstainers (self-reported, verified by exhaled CO < 10 ppm) and nonabstainers, not able to stay abstinent since baseline. The group of the nonabstainers was stratified in 2 subgroups, the reducers (smoked < 50% of baseline number of cpd) and relapsers (smoked 50-100% of baseline cpd).

MAIN OUTCOME MEASURES

Plasma viscosity, erythrocyte deformability, fibrinogen, transcutaneous partial oxygen tension (tcpO2), hematocrit, white blood cells, cotinine and thiocyanate plasma concentrations and exhaled CO, all assessed at 4, 8, 12 and 26 weeks.

RESULTS

After 6 months, plasma fibrinogen (228.2 vs. 275.4 mg/dl at baseline, p < 0.001), tcpO2 (50.4 vs. 34.9 mm mercury at baseline, p < 0.0001) were significantly improved in abstainers, but changes in plasma viscosity and erythrocyte deformability were inconclusive. Cotinine and thiocyanate (abstainers: 6.2 ng/ml at week 26 vs. 10.4 ng/ml at baseline, p < 0.0001) and expired CO (abstainers: 30.4 vs. 4.2 ppm, control vs. week 26, p < 0.0001) accurately followed the changes in smoking and/or NRT use in all of the groups. Other CV risk factors such as hematocrit and white blood cell count decreased to a greater extent in abstainers than in reducers and relapsers. Not only abstainers but also reducers did benefit of the temporarily stop smoking.

CONCLUSIONS

Smoking cessation improved CV parameters despite the measured cotinine and thiocyanate plasma levels, and use of nicotine medications did not negate these improvements. A smoking cessation for a short time and smoking of reduced cpd also improved these parameters temporarily.

Cross-species familiarity in shoaling fishes

Preferential association with familiar shoal mates confers a number of potentially important benefits to individuals, including improved anti-predator effects and the reduction of aggression in competitive interactions. Until now, however, familiarity has been demonstrated purely between conspecifics. Here, we present evidence that familiarity preferences can override natural preferences for conspecifics. Individual focal fishes (chub, Leuciscus cephalus) were given a choice of two stimulus shoals of the same size composed of conspecifics or of heterospecifics (minnows, Phoxinus phoxinus) in a flow tank. A series of four treatments was carried out to investigate the effects of familiarity, induced by a 15 day association between the focal fish and the stimulus fishes, on the choices made by the focal fish. Focal fishes showed a significant preference for conspecifics over heterospecifics when both stimulus shoals were composed of non-familiar individuals. Focal fishes also showed a significant preference for stimulus shoals composed of familiar fishes over stimulus shoals composed of non-familiar fishes when both shoals were conspecific and when both shoals were heterospecific. Finally, the preference of focal fishes for conspecifics disappeared when the alternative, a shoal of heterospecifics, was composed of familiar individuals. The importance of this work is discussed in the context of species interactions in free-ranging shoals.

[Intraoperative neurolysis of the celiac plexus in patients with unresectable pancreatic cancer]

BACKGROUND

The analgetic treatment of inoperable pancreatic cancer patients is of paramount importance. The relative ineffectiveness of pharmacological agents has led many investigators to recommend chemical neurolysis of the celiac ganglions for pain control. However, the assessment of the results and the effectiveness of the block carried out during laparotomy have been unclear.

PATIENTS AND METHODS

After 41 intraoperative celiac neurolytic blocks pain intensity was retrospectively analysed in 38 patients suffering from unresectable pancreatic carcinoma. The mean age of the patients was 59 years, the observation period after neurolysis ranged to 6 months. All patients underwent definitive neurolysis using 50 % ethanol in 0.5 % prilocaine. Immediate and long-term efficacy, analgetic consumption and mortality were evaluated at follow-up. The calculated parenteral equivalent morphine dosage (mg per day) was evaluated before as well as at different time points after treatment as an objective parameter to describe pain intensity.

RESULTS

7 to 34 days (at discharge from the hospital) after block pain intensity was statistically highly significant reduced (p=0.016). Long-term results were obtained from 17 (10 to 12 weeks after intervention) and 9 (up to 20 weeks after intervention) patients respectively, demonstrating a long-lasting effect of the neurolysis. A statistical analysis was not possible because of the small patient 's number.

CONCLUSIONS

Intraoperative celiac neurolytic block is a safe and effective method of pain treatment in patients with unresectable pancreatic carcinoma. However, it alone provides complete pain relief until death only in a few cases. Therefore, it should be considered as an adjuvant treatment in the analgesic strategy. Combined palliative therapy is necessary in most of the cases.