Building the Perfect Parasite: Cell Division in Apicomplexa

Apicomplexans are pathogens responsible for malaria, toxoplasmosis, and crytposporidiosis in humans, and a wide range of livestock diseases. These unicellular eukaryotes are stealthy invaders, sheltering from the immune response in the cells of their hosts, while at the same time tapping into these cells as source of nutrients. The complexity and beauty of the structures formed during their intracellular development have made apicomplexans the darling of electron microscopists. Dramatic technological progress over the last decade has transformed apicomplexans into respectable genetic model organisms. Extensive genomic resources are now available for many apicomplexan species. At the same time, parasite transfection has enabled researchers to test the function of specific genes through reverse and forward genetic approaches with increasing sophistication. Transfection also introduced the use of fluorescent reporters, opening the field to dynamic real time microscopic observation. Parasite cell biologists have used these tools to take a fresh look at a classic problem: how do apicomplexans build the perfect invasion machine, the zoite, and how is this process fine-tuned to fit the specific niche of each pathogen in this ancient and very diverse group? This work has unearthed a treasure trove of novel structures and mechanisms that are the focus of this review

Small Intestine Early Innate Immunity Response during Intestinal Colonization by Escherichia coli Depends on Its Extra-Intestinal Virulence Status

International audienceUropathogenic Escherichia coli (UPEC) strains live as commensals in the digestive tract of the host, but they can also initiate urinary tract infections. The aim of this work was to determine how a host detects the presence of a new UPEC strain in the digestive tract. Mice were orally challenged with UPEC strains 536 and CFT073, non-pathogenic strain K12 MG1655, and ΔPAI-536, an isogenic mutant of strain 536 lacking all 7 pathogenicity islands whose virulence is drastically attenuated. Intestinal colonization was measured, and cytokine expression was determined in various organs recovered from mice after oral challenge. UPEC strain 536 efficiently colonized the mouse digestive tract, and prior Enterobacteriaceae colonization was found to impact strain 536 colonization efficiency. An innate immune response, detected as the production of TNFα, IL-6 and IL-10 cytokines, was activated in the ileum 48 hours after oral challenge with strain 536, and returned to baseline within 8 days, without a drop in fecal pathogen load. Although inflammation was detected in the ileum, histology was normal at the time of cytokine peak. Comparison of cytokine secretion 48h after oral gavage with E. coli strain 536, CFT073, MG1655 or ΔPAI-536 showed that inflammation was more pronounced with UPECs than with non-pathogenic or attenuated strains. Pathogenicity islands also seemed to be involved in host detection, as IL-6 intestinal secretion was increased after administration of E. coli strain 536, but not after administration of ΔPAI-536. In conclusion, UPEC colonization of the mouse digestive tract activates acute phase inflammatory cytokine secretion but does not trigger any pathological changes, illustrating the opportunistic nature of UPECs. This digestive tract colonization model will be useful for studying the factors controlling the switch from commensalism to pathogenicity

Desipramine attenuates working memory impairments induced by partial loss of catecholamines in the rat medial prefrontal cortex

The density of tyrosine hydroxylase-immunoreactive (TH-IR) axons in the prefrontal cortex of schizophrenic subjects may be reduced by as much as 50% in the deep cortical layers (Am J Psychiatry 156:1580–1589, 1999). Previously, we demonstrated that ~60% loss of TH-IR axons in the rat medial prefrontal cortex (mPFC) decreases local basal and stress-evoked extracellular dopamine (DA) concentrations, suggesting that moderate loss of DA axons in the mPFC is sufficient to alter the neurochemical activity of the remaining DA neurons (Neuroscience 93:497–505, 1999).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46372/1/213_2005_Article_221.pd

Enteric helminths promote Salmonella co-infection by altering the intestinal metabolome

Intestinal helminth infections occur pre dominantly in regions where exposure to enteric bacterial pathogens is also common. Helminth infections inhibit host immunity against microbial pathogens, which has largely been attributed to the induction of regulatory or type 2 (Th2) immune responses. Here we demonstrate an additional three-way interaction in which helminth infection alters the metabolic environment of the host intestine to enhance bacterial pathogenicity. We show that an ongoing helminth infection increased colonization by Salmonella independently of T regulatory or Th2 cells. Instead, helminth infection altered the metabolic profile of the intestine, which directly enhanced bacterial expression of Salmonella pathogenicity island 1 (SPI-1) genes and increased intracellular invasion. These data reveal a novel mechanism by which a helminth-modified metabolome promotes susceptibility to bacterial co-infection

Predicting 1-year mortality among patients with decompensated cirrhosis:results of a multicentre evaluation of the Bristol Prognostic Score

Objective Chronic liver disease continues to be a significant cause of morbidity and mortality yet remains challenging to prognosticate. This has been one of the barriers to implementing palliative care, particularly at an early stage. The Bristol Prognostic Score (BPS) was developed to identify patients with life expectancy less than 12 months and to act as a trigger for referral to palliative care services. This study retrospectively evaluated the BPS in a cohort of patients admitted to three Scottish hospitals. Method Routinely collated healthcare data were used to obtain demographics, BPS and analyse 1-year mortality for patients with decompensated liver disease admitted to three gastroenterology units over two 90-day periods. Statistical analysis was undertaken to assess performance of BPS in predicting mortality. Results 276 patients were included in the final analysis. Participants tended to be late middle-aged men, socioeconomically deprived and have alcohol-related liver disease. A similar proportion was BPS+ve (>3) in this study compared with the original Bristol cohort though had more hospital admissions, higher ongoing alcohol use and poorer performance status. BPS performed poorer in this non-Bristol group with sensitivity 54.9% (72.2% in original study), specificity 58% (83.8%) and positive predictive value (PPV) 43.4% (81.3%). Conclusion BPS was unable to accurately predict mortality in this Scottish cohort. This highlights the ongoing challenge of prognostication in patients with chronic liver disease, furthering the call for more work in this field.Publisher PDFPeer reviewe

Is There Any Interaction Between Sex and Renal Function Change During Hospital Stay in Patients Hospitalized With Acute Heart Failure?

Background: Renal dysfunction is a strong predictor of outcomes in patients with acute heart failure (AHF). However. less is known about how sex may influence the prognostic import of renal function in AHF. Methods and Results: In a post hoc analysis of the ASCEND-HF trial including 5377 patients with AHF (33% female), patients were categorized into 3 groups based on the changes in renal function during their hospital stay. Worsening. stable, and improving renal functions were defined as a >= 20% decrease, a = 20% increase in the estimated glomentlar filtration rate, respectively. The primary outcome was the composite of 30-day all-cause mortality or HF rehospitalization. The median baseline and discharge estimated glomerular filtration rate were 58.4 and 56.9 mL/min/l.73 m(2), respectively. Worsening, stable, and improving renal function was observed in 31.9%, 63.2, and 4.9% of patients. respectively. Worsening renal function was associated with adverse outcomes at 30 days (adjusted hazard ratio [aHR] 1.47, 95% confidence interval [CI] 1.22-1.76). This association existed in both males and females (aHR 1.42 and aHR 1.56, respectively, both P < .01). There was an interaction between renal function changes and sex (P = .025), because improving renal function was associated with better outcomes in men(aHR 0.29, 95% CI 0.13 0.66) as compared with women (aHR 1.18, 95% CI 0.59 2.35). There was no interaction between the ejection fraction and renal function in association with subsequent outcomes. Conclusions: Irrespective of sex, worsening renal function was associated with poorer outcomes at 30 days in patients with AHF. More studies are warranted to further delineate the possible sex differences in this setting

SCOPE New Photographic Practices

The photographic practices brought together for this exhibition and publication provide a broad scope of how photographic and lens based media may be used in order to have a visceral and conceptual impact. The methods on show demonstrate the way that artists might pick and choose from the approaches, processes and debates that have arisen through the medium’s history. This collection of work features film, video and photography that demand a renegotiation of the relationship between camera, subject and viewer. Visual Art Centre Gallery, Tsinghua University, Beijing, Chin