An experimental in-vivo canine model for adult shunt infection

<p>Abstract</p> <p>Background</p> <p>Detailed human studies of the mechanisms and development of shunt infection in real time are not possible, and we have developed a canine hydrocephalus model to overcome this. The intention of this pilot study was to show that the canine hydrocephalus model could be shunted using conventional "human" shunts, and that a shunt infection could be established so that further studies could then be planned.</p> <p>Methods</p> <p>Hydrocephalus was induced in seven dogs (<it>Canis familiaris</it>) by fourth ventricle obstruction. Four weeks later they were shunted using a Hakim Precision valve. Four of the dogs received shunts whose ventricular catheter had been inoculated with <it>Staphylococcus epidermidis</it>, and three were uninoculated controls. Four weeks after shunting the dogs were sacrificed and necropsy was performed. Removed shunts and tissue samples were examined microbiologically and isolates were subjected to detailed identification and genomic comparison.</p> <p>Results</p> <p>All the dogs remained well after shunting. Examination of removed shunt components revealed <it>S. epidermidis </it>in the brain and throughout the shunt system in the four inoculated animals, but in two of these <it>Staphylococcus intermedius </it>was also found. <it>S. intermedius </it>was also isolated from all three "negative" controls. There were slight differences between <it>S. intermedius </it>strains suggesting endogenous infection rather than cross- infection from a point source.</p> <p>Conclusion</p> <p>Shunt infection was established in the canine model, and had the experiment been extended beyond four weeks the typical microbiological, pathological and clinical features might have appeared. The occurrence of unplanned shunt infections in control animals due to canine normal skin flora reflects human clinical experience and underlines the usual source of bacteria causing shunt infection.</p

Hydrodynamics of the Certas™ programmable valve for the treatment of hydrocephalus

<p>Abstract</p> <p>Background</p> <p>The new Certas™ shunt for the treatment of hydrocephalus has seven standard pressure settings that according to the manufacturer range from 36 to 238 mmH₂O, and an additional “Virtual Off” setting with an opening pressure >400 mmH₂O. Information on actual pressure response and reliability of shunt performance is important in clinical application, especially the “Virtual Off” setting as a non-surgical replacement for shunt ligation. The objective of this study was to evaluate the <it>in-vitro</it> hydrodynamic performance of the Certas™ shunt.</p> <p>Methods</p> <p>Six new Certas™ shunts with proximal and distal catheters were tested with an automated, computerized test system that raised the pressure from zero to a maximum pressure and back to zero at each valve setting. Opening pressure and flow resistance were determined.</p> <p>Results</p> <p>For settings 1–7 the measured opening pressure range was 26 to 247 mmH₂O, and the mean change in opening pressure for a one-step adjustment was between 33 and 38 mmH₂O. For setting 8 (“Virtual Off”) the measured mean opening pressure was 494 ± 34 mmH₂O (range 451 to 556 mmH₂O). The mean outflow resistance was 7.0 mmHg/ml/min (outflow conductance 17.9 μl/s/kPa).</p> <p>Conclusions</p> <p>The six shunts had similar characteristics and closely matched the manufacturer’s specifications for opening pressure at settings 1–7. The opening pressure for the “Virtual Off” setting was nearly 500 mmH₂O, which is 100 mmH₂O higher than the manufacturer’s specification of “>400” and should be functionally off for most patients with communicating hydrocephalus. Clinical studies are needed to evaluate if the CSF dynamic profile persists after implantation in patients.</p

Text messaging and financial incentives to encourage weight loss in men with obesity: the Game of Stones feasibility RCT

Funding: This project was funded by the National Institute for Health Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 8, No. 11. See the NIHR Journals Library website for further project information.Peer reviewedPublisher PD

High Levels of Antiretroviral Use and Viral Suppression Among Persons in HIV Care in the United States, 2010

Contemporary data on patterns of antiretroviral therapy (ART) use in the U.S. are needed to inform efforts to improve the HIV care cascade

A Rocket-Base Study of Auroral Electrodynamics Within the Current Closure Ionosphere

The Auroral Current and Electrodynamics Structure (ACES) mission consisted of two sounding rockets launched nearly simultaneously from Poker Flat Research Range, AK on January 29, 2009 into a dynamic multiple-arc aurora. The ACES rocket mission, in conjunction with the PFISR Radar, was designed to observe the three-dimensional current system of a stable auroral arc system. ACES utilized two well instrumented payloads flown along very similar magnetic field footprints, at various altitudes with small temporal separation between both payloads. ACES High, the higher altitude payload (apogee 360 km), took in-situ measurements of the plasma parameters above the current closure region to provide the input signature into the lower ionosphere. ACES Low, the low-altitude payload (apogee 130 km), took similar observations within the current closure region, where cross-field currents can flow. We present results comparing observations of the electric fields, magnetic fields, electron flux, and the electron temperature at similar magnetic footpoints between both payloads. We further present data from all-sky imagers and PFISR detailing the evolution of the auroral event as the payloads traversed regions connected by similar magnetic footpoints. Current measurements derived from the magnetometers on both payloads are further compared. We examine data from both PFISR and observations on the high-altitude payload which we interpreted as a signature of electron acceleration by means of Alfv n waves. We further examine all measurements to understand ionospheric conductivity and how energy is being deposited into the ionosphere through Joule heating. Data from ACES is compared against models of Joule heating to make inferences regarding the effect of collisions at various altitudes

Health behaviors and their relationship with disease control in people attending genetic clinics with a family history of breast or colorectal cancer

The current work aimed to assess health behaviors, perceived risk and control over breast/colorectal cancer risk and views on lifestyle advice amongst attendees at cancer family history clinics. Participants attending the East of Scotland Genetics Service were invited to complete a questionnaire (demographic data, weight and height, health behaviors and psycho-social measures of risk and perceived control) and to participate in an in-depth interview. The questionnaire was completed by 237 (49%) of attendees, ranging from 18 to 77years (mean age 46 (&plusmn;10) years). Reported smoking rates (11%) were modest, most (54%) had a BMI&gt;25kg/m2, 55% had low levels of physical activity, 58% reported inappropriate alcohol intakes and 90% had fiber intakes indicative of a low plant diet. Regression analysis indicated that belief in health professional control was associated with higher, and belief in fatalism with poorer health behavior. Qualitative findings highlighted doubts about the link between lifestyle and cancer, and few were familiar with the current evidence. Whilst lifestyle advice was considered interesting in general there was little appetite for non-tailored guidance. In conclusion, current health behaviors are incongruent with cancer risk reduction guidance amongst patients who have actively sought advice on disease risk. There are some indications that lifestyle advice would be welcomed but endorsement requires a sensitive and flexible approach, and the acceptability of lifestyle interventions remains to be explored

Auroral Current and Electrodynamics Structure (ACES) Observations of Ionospheric Feedback in the Alfven Resonator

In 2009, the Auroral Current and Electrodynamics Structure (ACES) High and Low sounding rockets were launched from the Poker Flat Rocket Range (PFRR) in Alaska, with the science objective of gathering in-situ data to quantify current closure in a discrete auroral arc. As ACES High crossed through the return current of an arc (that was monitored using an all sky camera from the ground at Fort Yukon), its instruments recorded clear Alfv nic signatures both poleward and equatorward of the return current region, but not within the main region of the return current itself. These data provide an excellent opportunity to study ionospheric feedback and how it interacts with the Alfv n resonator. We compare the observations with predictions and new results from a model of ionospheric feedback in the ionospheric Alfv n resonator (IAR) and report the significance and impact of these new data for the Magnetosphere-Ionosphere Coupling in the Alfv n Resonator (MICA) rocket mission to launch from PFRR this winter. MICA s primary science objectives specifically focus on better understanding the small-scale structure that the model predicts should exist within the return current region