Enzootic transmission of the agent of human granulocytic ehrlichiosis among cottontail rabbits

To determine whether the agent of human granulocytic ehrlichiosis (HGE) (Anaplasma phagocytophilum) may be maintained in a parallel enzootic cycle between cottontail rabbits and their ticks, we sampled these hosts from a zoonotic site during five transmission seasons. Evidence of infection was sought by microscopy and polymerase chain reaction from rabbit blood or splenic tissue, and from ticks collected from rabbits or from vegetation. Approximately 27% of all rabbits sampled contained evidence of active infection, and 66% were seropositive. The vectorial capacity of Ixodes dentatus was demonstrated by xenodiagnosis studies; in addition, 2% of host-seeking nymphs were infected. Haemaphysalis leporispalustris was not a competent vector. Because of their propensity to densely inhabit peridomestic sites, and because I. dentatus may be transported by birds, a parallel cycle of transmission in cottontail rabbits would facilitate introduction and perpetuation of the agent of HGE.     

Does flecainide regain its antiarrhythmic activity after electrical cardioversion of persistent atrial fibrillation?

OBJECTIVES: The purpose of this study was to evaluate the hypothesis that presumed reversion of electrical remodeling after cardioversion of atrial fibrillation (AF) restores the efficacy of flecainide. BACKGROUND: Flecainide loses its efficacy to cardiovert when AF has been present for more than 24 hours. Most probably, the loss is caused by atrial electrical remodeling. Studies suggest electrical remodeling is completely reversible within 4 days after restoration of sinus rhythm (SR). METHODS: One hundred eighty-one patients with persistent AF (median duration 3 months) were included in this prospective study. After failure of pharmacologic cardioversion by flecainide 2 mg/kg IV (maximum 150 mg in 10 minutes) and subsequent successful electrical cardioversion, we performed intense transtelephonic rhythm monitoring three times daily for 1 month. In case of AF recurrence, a second cardioversion by flecainide was attempted as soon as possible. RESULTS: AF recurred in 123 patients (68%). Successful cardioversion by flecainide occurred only when SR had been maintained for more than 4 days (7/51 patients [14%]). Failure to cardiovert was associated with a prolonged duration of the recurrent AF episode and concurrent digoxin use. Multivariate logistic regression confirmed that successful cardioversion was determined by digoxin use (odds ratio [OR] 0.093, P = .047) and by the interaction between the duration of SR and the (inverse) duration of recurrent AF (OR 6.499, P < .001). When flecainide was administered within 10 hours after AF onset and the duration of SR was greater than 4 days, the success rate was 58%. CONCLUSIONS: Flecainide recovers its antiarrhythmic action after cardioversion of AF. However, successful pharmacologic cardioversion occurs only after SR has lasted at least 4 days and is expected only for recurrences having duration of a few hours. Immediate pharmacologic cardioversion of AF recurrence may be a worthwhile strategy for management of persistent AF.     

Absence of transplacental transmission of Lyme disease spirochetes from reservoir mice (Peromyscus leucopus) to their offspring

Lyme disease spirochetes (Borrelia burgdorferi) are naturally maintained in an enzootic cycle mainly by vector ticks (Ixodes dammini) infesting white-footed mice (Peromyscus leucopus). Suggestions that mice may become infected without exposure to ticks prompted a study to evaluate whether mice could transmit spirochetes transplacentally to their offspring. Mice were live-captured in two Massachusetts sites where Lyme disease spirochetes are intensely enzootic. Pregnant females were housed separately in the laboratory through delivery, and mothers and their offspring were caged together until weaning. Each female and two offspring were then examined for evidence of infection serologically and by tick xenodiagnosis. All 14 mother mice examined produced infected ticks and exhibited serum antibodies to B. burgdorferi. However, none of 28 offspring tested produced infected ticks and only a few had evidence of circulating antibody. In a separate experiment, no young CD-1 mice, born of infected mothers, had IgM antibody to B. burgdorferi. It would appear that immature mice are not transplacentally infected with spirochetes and must be exposed to infected ticks before becoming infected and infective themselves.     

Outcome of Repeat ERCP After Initial Failed Use of a Needle Knife for Biliary Access

Introduction  

A needle knife is often used to gain bile duct access when standard techniques have failed. If unsuccessful, the next step may involve either radiological- or endoscopic ultrasound-guided biliary access. However, repeat endoscopic retrograde cholangiopancreatography (ERCP) may be an option if the patient’s clinical condition permits.     

The Effect of Court Location and Available Time on the Tactical Shot Selection of Elite Squash Players

No previous research in squash has considered the time between shots or the proximity of the ball to a wall, which are two important variables that influence shot outcomes. The aim of this paper was to analyse shot types to determine the extent to which they are played in different court areas and a more detailed analysis to determine whether the time available had an influence on the shot selected. Ten elite matches, contested by fifteen of the world’s top right handed squash players (age 27 ± 3.2, height 1.81 ± 0.06 m, weight 76.3 ± 3.7 kg), at the men’s World Team Championships were processed using the SAGIT/Squash tracking system with shot information manually added to the system. Results suggested that shot responses were dependent upon court location and the time between shots. When these factors were considered repeatable performance existed to the extent that one of two shots was typically played when there was limited time to play the shot (< 1.20s). For example, it was clear that when players did not have a lot of time to hit the ball (low time i.e. < 1.06s, and mid time i.e. 1.06 - 1.20s) in the front left corner close to the side wall, the crosscourt lob was used frequently (44.30% and 36.31% respectively) whereas when there was more time this shot was seldom used (13.64%). Consequently variant and invariant behaviour were shown to exist in elite squash although for the first time it was suggested that the availability of time to play a shot contributed to which of these behaviours was evident. This analysis could be extended by adopting a case study approach to see how individual differences in strategy and tactics affect shot selections.

Key points

• Previous research has suggested that a playing strategy, elements decided in advance of the match, may be evident for elite players by examining court location and preceding shot type, however these parameters alone are unlikely to be sufficient predictors.
• At present there is no known analysis in squash, or indeed in any of the racket sports, that has quantified the time available to respond to different shot types. An understanding of the time interval between shots and the movement characteristics of the player responding to different shots according to the court positions might facilitate a better understanding of the dynamics that determine shot selection.
• Some elements of a general playing strategy were evident e.g. predominately hitting to the back left of the court, but tactical differences in shot selection were also evident on the basis of court location and time available to play a shot.

Key words: Strategy, tactics, SAGIT, invariant behaviour.     

Neuroimaging in children, adolescents and young adults with psychological trauma

Childhood psychological trauma is a strong predictor of psychopathology. Preclinical research points to the influence of this type of trauma on brain development. However, the effects of psychological trauma on the developing human brain are less known and a challenging question is whether the effects can be reversed or even prevented. The aim of this review is to give an overview of neuroimaging studies in traumatized juveniles and young adults up till 2012. Neuroimaging studies in children and adolescents with traumatic experiences were found to be scarce. Most studies were performed by a small number of research groups in the United States and examined structural abnormalities. The reduction in hippocampal volume reported in adults with PTSD could not be confirmed in juveniles. The most consistent finding in children and adolescents, who experienced psychological trauma are structural abnormalities of the corpus callosum. We could not identify any studies investigating treatment effects. Neuroimaging studies in traumatized children and adolescents clearly lag behind studies in traumatized adults as well as studies on ADHD and autism.     

Transient bacteraemia: a possible cause of sudden life threatening events

The concept proposed is that transient bacteraemia occurring in otherwise healthy individuals can cause acute life threatening events due to bacterial toxaemia even though the bacteraemia is rapidly cleared (<20 min). This is most likely to occur in infancy at around two to three months of age when anti-toxin IgG reaches its nadir. Sudden unexpected death in infancy, acute life threatening events, haemorrhagic shock and encephalopathy, and the triad of retinal haemorrhage, encephalopathy and bilateral thin film subdural haematomata are conditions which could be caused by this mechanism. Investigations need to be directed to measuring bacterial toxins in blood, CSF and urine; anti-toxin IgG in blood; and bacterial specific nucleic acid sequences in blood, CSF and urine using polymerase chain reaction in order to confirm recent bacteraemia. Furthermore the upper respiratory tract bacterial flora should be mapped in cases and appropriately matched live healthy community controls. Sudden onset, profound life threatening physiological dysfunction occurring in later life could also be caused by a similar mechanism and should be investigated in a similar way; candidate conditions include epilepsy, migraine, stroke and cardiac arrhythmias.     

Assessing the use of the Family Affluence Scale (FAS) among Irish schoolchildren

The objective of this analysis was to examine the answering rates, internal reliability and external validity of the Family Affluence Scale (FAS) employing data from the 2002 Irish Health Behaviour in School-aged Children study HBSC; a cross-sectional survey of 8,424 Irish schoolchildren aged 10-18. Father's occupation was reported by 80.6% of the schoolchildren and 60.6% reported on mother's occupation, while over 96% reported on the FAS items. Lower answering rates on parental occupation were found among younger schoolchildren and among those with poorer material circumstances. Analysis of the FAS revealed a moderate internal reliability and FAS scores were significantly associated with reported parental occupation. The traditional SES measures suffer from poor answering rates that pose a serious methodological threat. The FAS has moderate internal reliability and does not capture the SES status in full, but it has high completion rates, and can be used as an additional measure of SES in late childhood and adolescence.