The first case of locally acquired tick-borne Babesia microti infection in Canada

A child with a complicated medical history that included asplenia acquired an infection with Babesia microti in the summer of 2013 and had not travelled outside of Manitoba. Although the clinical findings were subtle, astute laboratory work helped to reach a preliminary identification of Babesia species, while reference laboratory testing confirmed the diagnosis. Blacklegged ticks (Ixodes scapularis) are known to transmit Borrelia burgdorferi and Anaplasma phagocytophilum in the province; however, the present case represents the first known instance of tick-borne B microti, both in Manitoba and in Canada. The expanding territory of the blacklegged tick increases the relevance of this emerging infection. Clinicians, laboratory medical practitioners and public health officials should be aware of B microti as a potential locally acquired infection in Canada.     

The impact of periodontitis on oral health‐related quality of life: a review of the evidence from observational studies

Modern population based oral health management requires a complete understanding of the impact of disease in order to provide efficient and effective oral health care and guidance. Periodontitis is an important cause of tooth loss and has been shown to be associated with a number of systemic conditions. The impact of oral conditions and disorders on quality of life has been extensively studied. However, the impact of periodontitis on quality of life has received less attention. This review summarizes the literature on the impact of periodontitis on oral health‐related quality of life (OHRQoL). Relevant publications were identified after searching the MEDLINE and EMBASE electronic databases. Screening of titles and abstracts and data extraction was conducted. Only observational studies were included in this review. Most of the reviewed studies reported a negative impact of periodontitis on OHRQoL. However, the reporting standards varied across studies. Moreover, most of the studies were conducted in developed countries.     

Nitrite from inflammatory cells—A cancer risk factor in ulcerative colitis?

Elevated levels of luminal nitrite and a lowered luminal pH were found in 77 percent of patients with acute ulcerative colitis. No luminal nitrite was found in healthy control subjects. Nitrites are a secretory product of activated macrophages and neutrophils of the lamina propria, whereas the lowered luminal pH is due to diminished bicarbonate formation by impaired colonocytes. A hypothesis is put forward that nitrites, lowered pH, and bacterial amines are conducive to formation of carcinogenic n-nitroso compounds, which reflect a cancer risk in patients with ulcerative colitis dependent on the type and extent of inflammatory cell activation as well as metabolic impairment of colonic epithelial cells.     

Regulation of interleukin-12 expression in human monocytes: selective priming by interferon-gamma of lipopolysaccharide-inducible p35 and p40 genes

Interleukin-12 (IL-12) is a monocyte/macrophage-derived cytokine that is critical for T lymphocyte and natural killer cell activities and functions. In this study, we examined the regulation of IL-12 expression by human monocytes in response to bacterial lipopolysaccharide (LPS). Several novel aspects of IL-12 induction from monocytes were shown. Optimal expression of IL-12 mRNA and bioactivity required specific priming of monocytes by interferon-gamma (IFN-gamma) before LPS stimulation. Granulocyte-macrophage colony-stimulating factor (GM-CSF) provided an equivalent priming stimulus for LPS-induced tumor necrosis factor (TNF) and IL-12 p40 mRNA, but primed poorly for LPS-inducible p35 message and secreted IL-12 activity. Macrophage colony-stimulating factor (M-CSF), although a potent survival factor for monocytes, showed no priming activity for IL-12 production. Time course experiments demonstrated independent regulation of p40 and p35 by IFN-gamma and LPS. LPS inducibility of p40 expression required only a brief exposure to IFN-gamma (2 hours), while prolonged exposure (+/- 24 hours) to IFN-gamma resulted in diminishing levels of p40 mRNA. p35 inducibility (by LPS) required a longer exposure to IFN-gamma (8 to 16 hours), and continued to be inducible up to 40 hours following IFN- gamma priming. Both mRNAs were rapidly induced (1 to 2 hours) in IFN- gamma-primed monocytes; p35 message reached a plateau by 2 hours, while p40 continued to accumulate. Finally, both p40 and p35 were directly induced by LPS in the presence of cycloheximide. These results indicated that both p40 and p35 are LPS-inducible in monocytes following IFN-gamma pretreatment, and that the regulated expression of p35 controls the level of active IL-12 protein in purified human monocytes. The selectivity of priming by IFN-gamma is in accord with a putative role for IL-12 in the initiation and amplification of TH1-type responses.     

Antigen expression level threshold tunes the fate of CD8 T cells during primary hepatic immune responses

CD8 T-cell responses to liver-expressed antigens range from deletional tolerance to full effector differentiation resulting in overt hepatotoxicity. The reasons for these heterogeneous outcomes are not well understood. To identify factors that govern the fate of CD8 T cells activated by hepatocyte-expressed antigen, we exploited recombinant adenoassociated viral vectors that enabled us to vary potential parameters determining these outcomes in vivo. Our findings reveal a threshold of antigen expression within the liver as the dominant factor determining T-cell fate, irrespective of T-cell receptor affinity or antigen cross-presentation. Thus, when a low percentage of hepatocytes expressed cognate antigen, high-affinity T cells developed and maintained effector function, whereas, at a high percentage, they became functionally exhausted and silenced. Exhaustion was not irreversibly determined by initial activation, but was maintained by high intrahepatic antigen load during the early phase of the response; cytolytic function was restored when T cells primed under high antigen load conditions were transferred into an environment of low-level antigen expression. Our study reveals a hierarchy of factors dictating the fate of CD8 T cells during hepatic immune responses, and provides an explanation for the different immune outcomes observed in a variety of immune-mediated liver pathologic conditions.The liver is acknowledged to possess unique tolerogenic properties, which have likely evolved to maintain immunological unresponsiveness toward food-derived and microbial antigens that enter the circulation via the gut (1, 2). This tolerogenic capability of the liver is demonstrated in animal models of liver transplantation, in which liver allografts are accepted across complete MHC mismatch barriers and are able to protect other donor tissues from rejection (reviewed in ref. 3). In humans, the tolerogenic hepatic environment is likely to contribute to impaired immune clearance of the hepatitis B virus (HBV) and hepatitis C virus (HCV), which result in persistent infection in a significant proportion of exposed individuals and are associated with major morbidity and mortality. In contrast, effective immune responses to hepatotropic pathogens leading to resolution of infection are observed in most hepatitis A and E virus infections, the majority of individuals infected with HBV during adulthood, and a minority of those infected by HCV (reviewed in refs. 4, 5). The liver is also susceptible to a variety of autoimmune-mediated conditions (6). Collectively, these observations indicate that effective immune responses can be initiated and/or sustained in the liver despite its apparent predisposition toward the generation of tolerance. Unfortunately, there is no small animal model in which to study the parameters that determine the balance between intrahepatic immunity and tolerance in viral hepatitis. Thus, the factors that shape immune outcome have not yet been identified.By studying the fate of antigen-specific CD8 T cells transferred into mice expressing antigen in the liver, it has been shown that, despite being a nonlymphoid organ, the liver is able to support primary CD8 T-cell activation (7). However, depending on the choice of antigen expressed and mode of delivery, the outcome of intrahepatic CD8 T-cell activation has been varied, ranging from deletion and/or functional silencing (8–10) to cytotoxic T lymphocyte (CTL) development (11, 12). This observed diversity of T-cell fates parallels the heterogeneous outcomes of liver-immune interactions observed during hepatotropic viral infections in humans. Thus, reconciliation of these findings holds the potential to yield critical insights into the immunopathological basis of immune-mediated liver disease as well as liver-associated tolerance.In this study, we developed an integrated system in which we manipulated parameters predicted to influence the generation of effector CD8 T cells encountering their cognate antigen on hepatocytes. By identifying three key determinants of the generation of functional effector cells in response to hepatocyte-expressed antigen, this study provides, for the first time to our knowledge, a unified model that explains and predicts the functional outcome of CD8 T-cell activation by liver-expressed antigen and reconciles findings from a number of previous studies that addressed this question.     

Clinical outcome of double crown-retained implant overdentures with zirconia primary crowns

PURPOSEThis retrospective study aims at the evaluation of implant-supported overdentures (IODs) supported by ceramo-galvanic double crowns (CGDCs: zirconia primary crowns + galvano-formed secondary crown).RESULTSOne of the 86 inserted implants failed during the healing period (cumulative survival rate (CSR) implants: 98.8%). During the prosthetic functional period (mean: 5.9 ± 2.2 years), 1 implant demonstrated an abutment fracture (CSR-abutments: 98.2%), and one case of peri-implantitis was detected. All IODs remained in function (CSR-denture: 100%). A total of 15 technical complications required interventions to maintain function (technical complication rate: 0.178 treatments/patients/year).CONCLUSIONConsidering the small sample size, the use of CGDCs for the attachment of IODs is possible without an increased risk of technical complications. However, for a final evaluation, results from a larger cohort are required.