Entamoeba histolytica and amoebic liver abscess in northern Sri Lanka: a public health problem.

Entamoeba histolytica (E. histolytica) is a facultative protozoan parasite implicated in amoebic liver abscesses (ALA), the most common extraintestinal manifestation of this infection. E. histolytica is endemic to sub-tropical and tropical countries and has been a major public health concern in northern Sri Lanka (SLK) for the last three decades. This has been attributed to a multitude of factors such as poor sanitation, hygiene, male sex, middle age, overcrowding, unsanitary practices in the production of indigenous alcoholic beverages, and alcohol consumption. Additionally, while rates of E. histolytica have declined substantially throughout the rest of the island, largely due to better infrastructure, it remains pervasive in the northern peninsula, which is generally less developed. Infection arises primarily from fecal-oral transmission through the consumption of contaminated drinking water containing cysts. Upon ingestion, cysts multiply into trophozoites and colonize the host colonic mucosa using lectin and cysteine proteases as virulence factors, leading to host invasion. Symptoms occur along a spectrum, from asymptomatology, to pyrexia, abdominal cramping, and amoebic dysentery. Colonization of the colon results in the formation of distinct flask-shaped ulcers along the epithelium, and eventual penetration of the lamina propria via the production of matrix metalloproteinases. ALA then develops through trophozoite migration via the mesenteric hepatic portal circulation, where microabscesses coalesce to form a single, large right-lobe abscess, commonly on the posterior aspect. The progression of infection to invasive disease is contingent on the unique interplay between host and pathogen factors, such as the strength of host-immunity to overcome infection and inherent pathogenicity of the Entamoeba species. As a preventable illness, E. histolytica complications such as ALA impose a significant burden on the healthcare system. This mini-review highlights epidemiological trends, risk factors, diagnostic modalities, treatment approaches, and opportunities for prevention of E. histolytica-induced ALA, to help address this endemic problem on the island of SLK.

The Role of Physical Activity Prescription in Cardiovascular Disease Prevention Amongst South Asian Canadians.

Unequivocal evidence suggests an increased prevalence of cardiovascular disease (CVD) amongst South Asian Canadians (SACs) compared to other ethnic cohorts, due to a combination of their unique cardiometabolic profile and environmental factors. This unfavorable CVD profile is characterized by an elevated risk of dyslipidemia, high apolipoprotein B/apolipoprotein A1 ratio, hypertension, glucose intolerance, type 2 diabetes mellitus, as well as increased BMI, body fat percentage, abdominal and visceral adiposity. Despite the overwhelming evidence for the effectiveness of physical activity (PA) in circumventing the onset of CVD and in the reduction of CVD risk factors, SACs are among the most physically inactive cohorts in Canada. This relates to a set of common and unique socio-cultural barriers, such as gender, beliefs and perceptions about illness, immigration, unfavorable PA environments, and their high prevalence of debilitating chronic diseases. Several strategies to improve PA participation rates in this high-risk population have been suggested, and include the implementation of culturally sensitive PA interventions, as well as clinician training in PA prescription through workshops that emphasize knowledge translation into clinical practice. Therefore, the purpose of this mini-review is to highlight and discuss: (1) the burden of heart disease in SACs (2) the cardiovascular benefits of PA for SACs; (3) factors affecting PA participation among SACs and how they can be addressed; (4) the impact of culturally sensitive PA prescription on CVD prevention; (5) barriers to culture-specific PA prescription by clinicians, and strategies to improve its use and impact.

Ventral, but not dorsal, hippocampus inactivation impairs reward memory expression and retrieval in contexts defined by proximal cues.

The hippocampus (HPC) has been widely implicated in the contextual control of appetitive and aversive conditioning. However, whole hippocampal lesions do not invariably impair all forms of contextual processing, as in the case of complex biconditional context discrimination, leading to contention over the exact nature of the contribution of the HPC in contextual processing. Moreover, the increasingly well-established functional dissociation between the dorsal (dHPC) and ventral (vHPC) subregions of the HPC has been largely overlooked in the existing literature on hippocampal-based contextual memory processing in appetitively motivated tasks. Thus, the present study sought to investigate the individual roles of the dHPC and the vHPC in contextual biconditional discrimination (CBD) performance and memory retrieval. To this end, we examined the effects of transient post-acquisition pharmacological inactivation (using a combination of GABAA and GABAB receptor agonists muscimol and baclofen) of functionally distinct subregions of the HPC (CA1/CA3 subfields of the dHPC and vHPC) on CBD memory retrieval. Additional behavioral assays including novelty preference, light-dark box and locomotor activity test were also performed to confirm that the respective sites of inactivation were functionally silent. We observed robust deficits in CBD performance and memory retrieval following inactivation of the vHPC, but not the dHPC. Our data provides novel insight into the differential roles of the ventral and dorsal HPC in reward contextual processing, under conditions in which the context is defined by proximal cues.