Zinc Absorption from Micronutrient Powder Is Low but Is not Affected by Iron in Kenyan Infants

Interference with zinc absorption is a proposed explanation for adverse effects of supplemental iron in iron-replete children in malaria endemic settings. We examined the effects of iron in micronutrient powder (MNP) on zinc absorption after three months of home fortification with MNP in maize-based diets in rural Kenyan infants. In a double blind design, six-month-old, non-anemic infants were randomized to MNP containing 5 mg zinc, with or without 12.5 mg of iron (MNP + Fe and MNP − Fe, respectively); a control (C) group received placebo powder. After three months, duplicate diet collections and zinc stable isotopes were used to measure intake from MNP + non-breast milk foods and fractional absorption of zinc (FAZ) by dual isotope ratio method; total absorbed zinc (TAZ, mg/day) was calculated from intake × FAZ. Mean (SEM) TAZ was not different between MNP + Fe (n = 10) and MNP − Fe (n = 9) groups: 0.85 (0.22) and 0.72 (0.19), respectively, but both were higher than C (n = 9): 0.24 (0.03) (p = 0.04). Iron in MNP did not significantly alter zinc absorption, but despite intakes over double estimated dietary requirement, both MNP groups’ mean TAZ barely approximated the physiologic requirement for age. Impaired zinc absorption may dictate need for higher zinc doses in vulnerable populations.     

A multivariate model of determinants of change in gross-motor abilities and engagement in self-care and play of young children with cerebral palsy

A multivariate model of determinants of change in gross-motor ability and engagement in self-care and play provides physical and occupational therapists a framework for decisions on interventions and supports for young children with cerebral palsy and their families. Aspects of the child, family ecology, and rehabilitation and community services may influence children's activity and participation. Aspects of the child include primary and secondary impairments, associated and comorbid health conditions, and adaptive behaviors. Literature support for the model is reviewed. A clinical scenario illustrates the use of the model as a framework for practice. The model encourages therapists to broaden the focus of rehabilitation services for young children with CP to include not only development of motor abilities but also comprehensive interventions and supports to enhance participation in daily activities and routines. Therapists are encouraged to consider how child, family, and service factors interact when planning interventions and evaluating outcomes.     

Changes in the perceived quality of primary care in Shanghai and Shenzhen,China: a difference-in-difference analysis

ObjectiveTo assess changes in the quality of primary care in two megacities following the introduction of health system reforms in China.MethodsWe conducted multistage stratified random face-to-face surveys of patients visiting community health centres in Shanghai in 2011 and 2013, and Shenzhen in 2012 and 2013. Quality of primary care was measured using an assessment tool. Difference-in-difference analyses based on multiple linear regressions were used to compare the changes over time, after controlling for potential confounders.FindingsMost (2721) of the 3214 participants used a community health centre as their regular source of care and were included in our analyses. The mean total scores for quality of primary care were similar for Shanghai and Shenzhen at baseline. In Shenzhen, the mean total scores for all participants and those on low incomes had worsened by 0.922 (95% CI: 0.629 to 1.215) and 1.203 (95% CI: 0.397 to 2.009), respectively. In Shanghai, however, there were improvements in the mean total scores which included increases in the scores for first-contact utilization, continuity, coordination of information and comprehensiveness.ConclusionThe quality of primary care improved in Shanghai but not in Shenzhen. This may be because, in Shanghai, beneficial long-term relationships between patients and general practitioners were supported by capitation payments and the provision of services tailored to the local health priorities.     

Choroidal assessment in idiopathic panuveitis using optical coherence tomography

Background

Idiopathic panuveitis is a diagnosis of exclusion that lacks distinguishing features on fluorescein and indocyanine green angiography. Choroidal hypoperfusion or ischaemia has been implicated in panuveitis of different aetiologies. In this study, we use enhanced depth imaging optical coherence tomography (OCT) to examine the choroid and its vasculature in patients with this disease.

Methods

In this retrospective, cross-sectional study, OCT-derived measurements of retinal and choroidal thickness were obtained after manual segmentation using custom software. Choroidal measurements were further subdivided into Haller’s large vessel layer (HLVL) and Sattler’s medium vessel layer (SMVL), and correlated with clinical parameters.

Results

Twenty-one eyes from 21 patients were included. A reduction in hypo-reflective spaces, corresponding to vascular lumens, was observed in HLVL. The mean thickness of both the choroid (233.7?±?73.3 μm), and HLVL (167.8?±?53.7 μm), was less than that previously reported for normal eyes. Choroidal thickness expressed as a ratio to retina thickness showed significant correlation to visual acuity (r?=?0.58, p?=?0.006). This correlation was maintained in the ratio between HLVL and retinal thickness (r?=?0.56, p?=?0.009), but not in SMVL to retinal thickness (r?=?0.352, p?=?0.12).

Conclusions

This study reports novel OCT-derived parameters in patients with idiopathic panuveitis. We noted loss of hyporeflectivity in HLVL, and thinning of both HLVL and the choroid as a whole. The observed correlation between visual acuity and the ratio of choroidal to retinal thickness is a strong enhanced depth imaging (EDI)-OCT derived candidate for prospective validation in future studies.     

Minimally invasive plate osteosynthesis for humerus diaphyseal fractures

Background:

Minimally invasive plate osteosynthesis (MIPO) technique is reported as a satisfactory procedure for the treatment of humeral shaft fractures by the anterior approach by several authors. However, none of the published reports had a significant follow-up nor have they reported patient outcomes. We evaluated the clinical, radiographic, and functional outcome over a minimum follow-up of 2 years using the same MIPO technique to humeral shaft fracture.

Materials and Methods:

32 adult patients with diaphyseal fractures of the humerus treated with MIPO between June 2007 and October 2008 were included in the study. Patients with metabolic bone disease, polytrauma, and Gustilo and Anderson type 3 open fractures with injury severity score >16 were excluded from the study. All cases were treated with closed indirect reduction and locking plate fixation using the MIPO technique. The surgery time, radiation exposure, and time for union was noted. The shoulder and elbow function was assessed using the UCLA shoulder and Mayo elbow performance scores, respectively.

Results:

Of the 32 patients in the study, 19 were males and 13 were females. The mean age was 39 years (range: 22–70 years). Twenty-seven of the thirty-two patients (84.3%) had the dominant side fractured. We had eight cases of C2 type; five cases of C1 and A2 type; four cases of B2 type; three cases each of B3, B1, and A1 type; and one case of A3 type of fracture. The mean surgical time was 91.5 minutes (range: 70–120 minutes) and mean radiation exposure was 160.3 seconds (range: 100–220 seconds). The mean radiological fracture union time was 12.9 weeks (range: 10–20 weeks). Shoulder function was excellent in 27 cases (84.3%) and good in remaining 5 cases (15.6%) on the UCLA score. Elbow function was excellent in 26 cases (81.2%), good in 5 cases (15.6%), and fair in 1 case (3.1%) who had an associated olecranon fracture that was fixed by tension band wire in the same sitting.

Conclusion:

MIPO of the humerus gives good functional and cosmetic results and should be considered one of the management options in the treatment of humeral diaphyseal fractures.     

Dendritic Cells Inhibit the Progression of Listeria monocytogenes Intracellular Infection by Retaining Bacteria in Major Histocompatibility Complex Class II-Rich Phagosomes and by Limiting Cytosolic Growth

Dendritic cells (DC) provide a suboptimal niche for the growth of Listeria monocytogenes, a facultative intracellular bacterial pathogen of immunocompromised and pregnant hosts. This is due in part to a failure of large numbers of bacteria to escape to the cytosol, an essential step in the intracellular life cycle that is mediated by listeriolysin O (LLO). Here, we demonstrate that wild-type bacteria that failed to enter the cytosol of bone marrow-derived DC were retained in a LAMP2⁺ compartment. An isogenic L. monocytogenes strain that produces an LLO protein with reduced pore-forming activity had a severe escape and growth phenotype in DC. Few mutant bacteria entered the cytosol in the first 2 h and were instead found in LAMP2⁺, major histocompatibility complex class II⁺ (MHC-II⁺) H2-DM vesicles characteristic of MHC-II antigen loading compartments (MIIC). In contrast, the mutant had a minor phenotype in bone marrow-derived macrophages (BMM) despite the reduced LLO activity. In the first hour, DC phagosomes acidified to a pH that was, on average, half a point higher than that of BMM phagosomes. Unlike BMM, L. monocytogenes growth in DC was minimal after 5 h, and consequently, DC remained viable and matured late in infection. Taken together, the data are consistent with a model in which phagosomal maturation events associated with the acquisition of MHC-II molecules present a suboptimal environment for L. monocytogenes escape to the DC cytosol, possibly by limiting the activity of LLO. This, in combination with an undefined mechanism that controls bacterial growth late in infection, promotes DC survival during the critical maturation response.Dendritic cells (DC) comprise a heterogeneous group of antigen-presenting cells (APC) that have the unique capacity to activate naïve T cells, and thus they are required for the initiation of an adaptive immune response (4). Immature DC link the innate to the adaptive immune response by sampling material from the local environment and differentiating in a manner appropriate to the ingested cargo. Maturation into APC capable of presenting antigens for the initiation of an adaptive immune response results when DC pattern recognition receptors encounter molecular signatures associated with pathogens (4, 25). In recent years, studies using predominantly bone marrow-derived myeloid DC and model antigens have indicated that the unique ability of DC to induce primary T-cell responses is a function of endosomal/lysosomal specializations that effectively preserve immunogenic peptides (26, 34, 43). Unlike other professional APC, antigen processing and presentation in DC is coupled to the receipt of appropriate maturation signals (25, 26). Immature DC have a high capacity to ingest soluble and particulate material and sequester it in major histocompatibility complex class II (MHC-II)-rich compartments (MIIC) (19, 30). The degradation and loading of peptides onto MHC-II, as well as the delivery to and retention of peptide-MHC complexes on the cell surface, is enhanced after the receipt and assimilation of inflammatory signals (11, 19, 30, 44). Recent evidence suggests that antigen degradation is limited in immature DC endosomes and lysosomes relative to that of macrophages by lower protease content as well as by an acidification response that controls the rate and extent of proteolysis (14, 26, 42). These adaptations have been proposed to prevent the destruction of immunogenic epitopes destined for presentation to T cells (14, 26, 35).Listeria monocytogenes belongs to a class of intracellular pathogens that must escape the host cell endosomal/lysosomal system in order to grow. L. monocytogenes infects a broad range of cell types, including DC, and the intracellular life cycle has been characterized in detail (31). The growth stage of the L. monocytogenes life cycle proceeds after the rupture of the phagosomal membrane by a pH- and cholesterol-dependent pore-forming cytolysin, listeriolysin O (LLO), with the assistance of a bacterial phosphatidylinositol-specific phospholipase C (PI-PLC). Within 30 min of uptake by macrophages, L. monocytogenes escapes from LAMP1-negative, late endosomal vesicles, which acidify to pH 5.5, providing an optimal environment for LLO-mediated pore formation (5, 18, 28). Consequently, the majority of L. monocytogenes can be found free and replicating in the macrophage cytosol in the first hour of infection. Bacterial escape is inefficient after phagosomal fusion with lysosomes (18), presumably due to a harsh environment (low pH, high proteolysis) that does not support LLO activity. L. monocytogenes thus takes advantage of a small window of opportunity within minutes after ingestion by macrophages, during which the phagosomal conditions are favorable for LLO to mediate bacterial escape to the cytosol. Once in the cytosol, L. monocytogenes recruits the host cell actin machinery to spread to adjacent cells by a process of intercellular spread. Escape from secondary spreading vacuoles, mediated by LLO in combination with two bacterial phospholipases (PI-PLC and a broad-range PLC, PC-PLC) (1), allows the infection to progress while shielding the bacteria from extracellular immune defenses of the host. The intracellular lifestyle dictates that clearance of the pathogen requires the processing and presentation of bacterial antigens via the MHC-I pathway and the activation of a CD8⁺ T-cell response (22). The presentation of antigens via the MHC-II pathway and activation of a CD4⁺ T-cell response is necessary for the maintenance of long-term CD8⁺ T-cell memory (41).DC mature in response to infection with wild-type (WT) L. monocytogenes (3, 9, 27) and are required for the initiation of an adaptive immune response in the murine intravenous model (21). We have previously reported that bone marrow-derived DC have the capacity to restrict large numbers of L. monocytogenes to a membrane-bound compartment and, consequently, to limit their intracellular growth (50). This is in contrast to bone marrow-derived macrophages (BMM), which support relatively unrestricted bacterial growth in the cytosol. Consistent with these findings, DC become infected with L. monocytogenes in vivo, but unlike macrophages, they do not appear to provide a significant niche for bacterial replication (2, 27). Given the critical role of DC in the immune response, the limitation of intracellular bacterial infection may preserve and enhance their specialized antigen-presenting function. Therefore, to begin to address how DC control L. monocytogenes growth, we examined the characteristics of DC phagosomes early after infection. Evidence is provided that phagosomal maturation events associated with the acquisition of MHC-II molecules reduce the efficiency of L. monocytogenes escape to the DC cytosol, possibly by presenting suboptimal environmental conditions for LLO. Along with an additional as-yet undefined mechanism that controls the extent of bacterial growth in the cytosol, these DC-specific responses to L. monocytogenes infection preserve cellular integrity during the course of the maturation response.     

Adipose tissue of human omentum is a major source of dendritic cells, which lose MHC Class II and stimulatory function in Crohn's disease

Adipose tissue is reported to contain monocyte-like pre-adipocytes, which may mature into macrophages, contributing to local inflammation. Dendritic cells (DC) can be derived from monocytes and initiate and regulate primary immune responses. We hypothesized, therefore, that adipose tissue may provide DC involved in local immune activity. To test this, we studied cells from human omental adipose tissue samples from 17 patients with benign gynecological disease. The hypothesis that adipose tissue DC are involved in inflammatory disease was tested by comparing these cells with those from 18 patients with Crohn's disease, where hypertrophy of adipose tissue suggests involvement in disease. A high proportion of the 1.33 +/- 0.12 x 10(5) CD45-positive cells/mg, obtained from control omenta, expressed CD11c, CD1a, and CD83; costimulatory molecules CD40, CD80, and CD86; and major histocompatibility complex (MHC) Class II but little CD14, CD16, or CD33. Omental cells showing morphological characteristics of DC were also observed. Metrizamide gradient-enriched DC from these populations were potent stimulators of primary proliferation of allogeneic T cells in mixed leukocyte reactions. Increased numbers of CD45+ cells from omentum of Crohn's patients (4.50+/-1.08 x 10(5) CD45+ cells/mg) contained higher percentages of CD11c+ and CD40+ cells (80.8+/-3.8% vs. 63.4+/-6, P=0.032; 77.9+/-4% vs. 58.8+/-6.5, P=0.029, respectively), but MHC Class II and stimulatory capacity were almost completely lost (P= <0.001), suggesting innate activation but lost capacity to stimulate adaptive immune responses. Granulocytes were also present amongst the omental cells from Crohn's patients. Results indicated that omentum may provide DC, which could "police" local infections and contribute to and/or reflect local inflammatory activity.     

Selective downregulation of prostaglandin E2-related pathways by the Th2 cytokine IL-13

BACKGROUND: Levels of COX-2 and downstream products, such as prostaglandin (PG) E2, are increased in inflammatory settings after stimulation by IL-1beta, LPS, and other innate factors. Although the TH2 cytokines IL-4 and IL-13 have been reported to decrease COX-2 levels in some cell types, neither the effect of these cytokines on other PGE2-related pathways nor their effect in primary human airway epithelial cells has been evaluated. OBJECTIVE: To determine the impact of IL-13 on PGE2 pathways in primary human airway epithelial cells. METHODS: Because PGE2 has anti-inflammatory, antifibrotic, and bronchodilating properties of relevance to asthma, the effect of IL-13 (10 ng/mL for 10 days) on PGE2 pathway elements in first-passage air-liquid interface epithelial cells from 8 endobronchial brushings (5 asthmatic subjects and 3 healthy subjects) was evaluated. mRNA and protein levels for COX-1 and COX-2, membrane-bound PGE synthase 1, 15-PG dehydrogenase, and the receptors EP2 and EP4 were quantified by means of real-time PCR and Western blotting. PGE2 levels in the supernatants were measured by means of enzyme immunoassay. RESULTS: IL-13 significantly inhibited the PGE2 synthetic pathways COX-2 and PGE synthase 1 while upregulating the PGE2 metabolizing enzyme 15-PG dehydrogenase. These enzymatic changes associated and correlated with decreased supernatant PGE2 levels. Significant reductions in the mRNA for EP2 (but not EP4) were also observed. Changes in the PG pathway were both time and dose dependent (n = 3). CONCLUSION: These data suggest that IL-13 induces systematic modulation of proteins related to the production, catabolism, and function of PGE2, which might alter inflammatory and immune responses at the level of the epithelium and the submucosa below. CLINICAL IMPLICATIONS: Modulation of PGE2 pathways by IL-13 might alter inflammatory and repair processes in asthma.