High-resolution contrast-enhanced MRI of atherosclerosis with digital cardiac and respiratory gating in mice.

Atherosclerosis initially develops predominantly at the aortic root and carotid origin, where effective visualization in mice requires efficient cardiac and respiratory gating. The present study sought to first compare the high-resolution MRI gating performance of two digital gating strategies using: 1) separate cardiac and respiratory signals (double-sensor); and 2) a single-sensor cardiorespiratory signal (ECG demodulation), and second, to apply an optimized processing technique to dynamic contrast-enhanced (CE) carotid origin vessel-wall imaging in mice. High-resolution MR mouse heart and aortic arch images were acquired by ECG signal detection, digital signal processing, and gating signal generation modeled using Simulink (MathWorks, USA). Double-sensor gating used a respiratory sensor while single-sensor gating used breathing-modulated ECG to generate a demodulated respiratory signal. Pre- and postcontrast T(1)-weighted images were acquired to evaluate vessel-wall enhancement with a gadolinium blood-pool agent (P792; Guerbet, France) at the carotid origin in vivo in ApoE(-/-) and C57BL/6 mice, using the optimized cardiorespiratory gating processing technique. Both strategies provided images with improved spatial resolution, less artifacts, and 100% correct transistor-to-transistor logic (TTL) signals. Image quality allowed vessel-wall enhancement measurement in all the ApoE(-/-) mice, with maximal (32%) enhancement 27 min postinjection. The study demonstrated the efficiency of both cardiorespiratory gating strategies for dynamic contrast-enhanced vessel-wall imaging.     

In vitro non-rigid life-size model of aortic arch aneurysm for endovascular prosthesis assessment.

PURPOSE: It is essential to evaluate new stent designs before in vivo testing. The purpose of this study was to develop and validate a controlled and reproducible patient-derived process to produce a life-size in vitro model of aortic arch aneurysm for endovascular procedure simulation. METHODS: A three-dimensional magnetic resonance angiography (3D MRA) image derived from a 60-year-old patient with aortic arch aneurysm was segmented using a home-made software package which allows one-click automatic segmentation of the aorta, meshing, and conversion to standard tessellation language (STL) format. A rapid prototyping technique established a stereolithographic model to produce a replica of the whole aorta, including the arch aneurysm and supra-aortic arteries. RESULTS: The final model was made by pouring silicone rubber to obtain a sturdy, life-size, soft, transparent, plastic cast, accurately reproducing both the internal and external anatomy of the aortic aneurysm. This model was used under perfusion by an extracorporeal circulation pump, to test ex vivo stent deployment. CONCLUSION: The combination of easy segmentation and conversion to the STL format with industrial stereolithography techniques enabled a realistic silicon vascular phantom to be created for endovascular procedure simulation, image modality calibration, and new stent design.     

Heart stopper genes: would you recognize a high risk patient?

Coronary artery disease (CAD) is one of the leading causes of death in the United States. Eighty percent of people having heart attacks have normal cholesterol levels. A quarter of the population have a condition called low-density lipoprotein (LDL) pattern B that has been associated with a threefold risk of myocardial infarction. Although early intervention can often prevent an otherwise fatal event, these patients often go unrecognized until after a myocardial infarction has occurred because they may not have the usual risk factors associated with cardiovascular disease. In patients with LDL pattern B, the standard lipid panel may be normal and inadequate for diagnosis and treatment of the condition. This article discusses how to identify a potentially high risk patient, available laboratory tests, management options, and the role of nurses in identifying high risk patients. The second author tells his personal story of surviving multiple cardiac arrests at a young age before being diagnosed with this condition.     

An Observational Case Study of Near-peer Teaching in Medical and Pharmacy Experiential Training

Objective. To compare peer teaching in a medical and a pharmacy clinical teaching unit and to provide suggestions for future research in pharmacy near-peer teaching.Methods. This exploratory observational study used principles of ethnographic methodology for data collection and analysis. Observations were collected in a large downtown teaching hospital. An average of 4-6 hours per day were spent observing a team of medical trainees from the Faculty (School) of Medicine in the general internal medicine (unit for two weeks, followed by a team of pharmacy trainees in an ambulatory hemodialysis (HD) unit for two weeks. Data was collected through field notes and informal interviews that were audiotaped and subsequently transcribed. Data was interpreted by the observer and reviewed weekly by two impartial pharmacists.Results. Five major themes emerged: (1) influence of peer teaching hierarchy; (2) educational distance between peer learners and teachers; (3) effect of the clinical teaching unit size on peer learning; (4) trainees’ perception of their teaching role in the clinical teaching unit; and (5) influence of daily schedule and workload on peer teaching. As opposed to pharmacy, a hierarchy and pyramidal structure of peer teaching was observed in medical experiential training. There appeared to be no effect of educational distance on near peer teaching; however, perception of teaching role and influence of daily schedule affected near-peer teaching.Conclusion. Through initial comparisons of medical and pharmacy clinical teaching units, this study provides a reflection of elements that may be necessary to successfully implement near-peer teaching in pharmacy experiential training. Future studies in this area should assess learning outcomes and participant satisfaction, preceptor workload, and impact on patient care.     

Female pelvic autonomic neuroanatomy based on conventional macroscopic and computer-assisted anatomic dissections

Purpose  

To confront nerve dissection, tissue staining, nerve immunolabelling and Computer-Assisted Anatomic Dissection (CAAD) in identifying the precise location and origin of intrapelvic autonomic nerve fibers and to provide a three-dimensional (3D) representation of their relationship to other anatomical structures.     

Evolution in the concept of erection anatomy

Purpose  

To review and to summarize the literature on anatomy and physiology of erection in the past three decades, especially the work done in our institution.     

Responses to pandemic AS03-adjuvanted A/California/07/09 H1N1 influenza vaccine in human immunodeficiency virus-infected individuals

ABSTRACT: BACKGROUND: Influenza infection may be more serious in human immunodeficiency virus (HIV)-infected individuals, therefore, vaccination against seasonal and pandemic strains is highly advised. Seasonal influenza vaccines have had no significant negative effects in well controlled HIV infection, but the impact of adjuvanted pandemic A/California/07/2009 H1N1 influenza hemaglutinin (HA) vaccine, which was used for the first time in the Canadian population as an authorized vaccine in autumn 2009, has not been extensively studied. OBJECTIVE: Assess vaccine-related effects on CD4+ T cell counts and humoral responses to the vaccine in individuals attending the Newfoundland and Labrador Provincial HIV clinic. METHODS: A single dose of ArepanrixTM split vaccine including 3.75 mug A/California/07/2009 H1N1 HA antigen and ASO3 adjuvant was administered to 81 HIV-infected individuals by intramuscular injection. Plasma samples from shortly before, and 1--5 months after vaccination were collected from 80/81 individuals to assess humoral anti-H1N1 HA responses using a sensitive microbead-based array assay. Data on CD4+ T cell counts, plasma viral load, antiretroviral therapy and patient age were collected from clinical records of 81 individuals. RESULTS: Overall, 36/80 responded to vaccination either by seroconversion to H1N1 HA or with a clear increase in anti-H1N1 HA antibody levels. Approximately 1/3 (28/80) had pre-existing anti-H1N1 HA antibodies and were more likely to respond to vaccination (22/28). Responders had higher baseline CD4+ T cell counts and responders without pre-existing antibodies against H1N1 HA were younger than either non-responders or responders with pre-existing antibodies. Compared to changes in their CD4+ T cell counts observed over a similar time period one year later, vaccine recipients displayed a minor, transient fall in CD4+ T cell numbers, which was greater amongst responders. CONCLUSIONS: We observed low response rates to the 2009 pandemic influenza vaccine among HIV-infected individuals without pre-existing antibodies against H1N1 HA and a minor transient fall in CD4+ T cell numbers, which was accentuated in responders. A single injection of the ArepanrixTM pandemic A/California/07/2009 H1N1 HA split vaccine may be insufficient to induce protective immunity in HIV-infected individuals without pre-existing anti-H1N1 HA responses.     

Profiling cellular bioenergetics,glutathione levels,and caspase activities in stomach biopsies of patients with upper gastrointestinal symptoms

AIM: To measure biochemical parameters in stomach biopsies and test their suitability as diagnostic biomarkers for gastritis and precancerous lesions.METHODS: Biopsies were obtained from the stomachs of two groups of patients(n = 40) undergoing fiberoptic endoscopy due to upper gastrointestinal symptoms. In the first group(n = 17), only the corpus region was examined. Biopsies were processed for microscopic examination and measurement of mitochondrial O2 consumption(cellular respiration), cellular adenosine triphosphate(ATP), glutathione(GSH), and caspase activity. In the second group of patients(n = 23), both corpus and antral regions were studied. Some biopsies were processed for microscopic examination, while the others were used for measurements of cellular respiration and GSH level.RESULTS: Microscopic examinations of gastric corpus biopsies from 17 patients revealed normal mucosae in 8 patients, superficial gastritis in 7 patients, and chronic atrophic gastritis in 1 patient. In patients with normal histology, the rate(mean ± SD) of cellular respiration was 0.17 ± 0.02 μmol/L O2 min-1 mg-1, ATP content was 487 ± 493 pmol/mg, and GSH was 469 ± 98 pmol/mg. Caspase activity was detected in 3 out of 8 specimens. The values of ATP and caspase activity were highly variable. The presence of superficial gastritis had insignificant effects on the measured biomarkers. In the patient with atrophic gastritis, cellular respiration was high andATP was relatively low, suggesting uncoupling oxidative phosphorylation. In the second cohort of patients, the examined biopsies showed either normal or superficial gastritis. The rate of cellular respiration(O2. μmol/L min-1 mg-1) was slightly higher in the corpus than the antrum(0.18 ± 0.05 vs 0.15 ± 0.04, P = 0.019). The value of GSH was about the same in both tissues(310 ± 135 vs 322 ± 155, P = 0.692).CONCLUSION: The corpus mucosa was metabolically more active than the antrum tissue. The data in this study will help in understanding the pathophysiology of gastric mucosa.