Radioactive choline metabolism in guinea pig gallbladder

Acetylcholine may be released from gallbladder intrinsic nerves in response to cholecystokinin stimulation. This study characterized metabolites of [¹⁴C]choline produced in the gallbladder and released during incubation, with or without cholecystokinin-octapeptide. Radiolabeled [¹⁴C]choline was applied to the mucosal or muscle surface of intact guinea pig gallbladders in an organ bath. After radiolabeling, gallbladders were incubated with or without the contractile agonist cholecystokinin-octapeptide. Metabolites of [¹⁴C]choline were identified in gallbladder tissue and incubation buffers using HPLC and thin-layer chromatography. The major metabolites of [¹⁴C]choline were betaine and phosphocholine. [¹⁴C]Phosphocholine was incorporated slowly into [¹⁴C]phosphatidylcholine. [¹⁴C]Choline was released into buffers during incubation. [¹⁴C]Acetylcholine constituted less than 1% of radiolabel in the gallbladder. There was no identifiable [¹⁴C]acetylcholine released in buffers. Cholecystokinin-octapeptide did not affect choline metabolism. These studies showed that choline in the gallbladder is metabolized along pathways similar to those in the liver. Gallbladders released mostly choline, rather than acetylcholine, even during hormonally induced contraction.This project was supported by the Research and Development Office of the Department of Veterans Affairs.     

The epitopes for some antiphospholipid antibodies are adducts of oxidized phospholipid and β2 glycoprotein 1 (and other proteins)

Circulating autoantibodies to phospholipids (aPLs), such as cardiolipin (CL), are found in patients with antiphospholipid antibody syndrome (APS). We recently demonstrated that many aPLs bound to CL only after it had been oxidized (OxCL), but not to a reduced CL analogue that could not undergo oxidation. We now show that the neoepitopes recognized by some aPLs consist of adducts formed between breakdown products of oxidized phospholipid and associated proteins, such as β₂ glycoprotein 1 (β₂GP1). Addition of human β₂GP1, polylysine, native low-density lipoprotein, or apolipoprotein AI to OxCL-coated wells increased the anticardiolipin antibody (aCL) binding from APS sera that first had been diluted so that no aCL binding to OxCL could be detected. No increase in aCL binding was observed when these proteins were added to wells coated with reduced CL. The ability of β₂GP1, polylysine, or low-density lipoprotein to be a “cofactor” for aCL binding to OxCL was greatly reduced when the proteins were methylated. Incubation of β₂GP1 with oxidized 1-palmitoyl-2-linoleyl-[1-¹⁴C]-phosphatidylcholine (PC), but not with dipalmitoyl-[1-¹⁴C]-PC, led to formation of covalent adducts with β₂GP1 recognized by APS sera. These data suggest that the reactive groups of OxCL, such as aldehydes generated during the decomposition of oxidized polyunsaturated fatty acids, form covalent adducts with β₂GP1 (and other proteins) and that these are epitopes for aCLs. Knowledge that the epitopes recognized by many aPLs are adducts of oxidized phospholipid and associated proteins, including β₂GP1, may give new insights into the pathogenic events underlying the clinical manifestations of APS.     

Foodborne botulism in a six-month-old infant caused by home-canned baby food

Previously reported cases of botulism in infants have been diagnosed as infant botulism; that is, botulism caused by intestinal colonization by Clostridium botulinum with intraluminal production and absorption of toxin. Foodborne botulism is caused by ingestion of preformed toxin. We describe an unusual case of foodborne botulism in a 6-month-old infant caused by the ingestion of improperly prepared home-canned baby food. This represents the youngest age of onset for foodborne botulism in the United States of which we are aware and illustrates the need to rule out foodborne botulism, which represents a public health emergency, regardless of the patient's age. The diagnosis could have been readily missed or delayed in this case because the weakness was rapidly progressive rather than insidious, as is typical of infant botulism.     

Fc receptor gamma-chain activation via hOSCAR induces survival and maturation of dendritic cells and modulates Toll-like receptor responses

We previously reported the characterization of human osteoclast-associated receptor (hOSCAR), a novel Fc receptor gamma-chain (FcRgamma)-associated receptor expressed by myeloid cells. Here we show that ligation of hOSCAR by specific antibodies promotes dendritic cell (DC) survival by an extracellular signal-regulated kinase (ERK)- and phosphatidylinositol 3-kinase (PI3K)-dependent pathway, linked to expression of the Bcl-2 and Bcl-x(L) antiapoptotic molecules. Crosslinking of hOSCAR leads to maturation of DCs, as demonstrated by up-regulation of maturation markers, decrease in dextran uptake capacity, and secretion of immunesystem effectors such as interleukin-8 (IL-8)/CXC chemokine ligand 8 (CXCL8), IL-12 p40, monocyte chemoattractant protein-1 (MCP-1)/chemokine receptor ligand 2 (CCL2) and macrophage-derived chemokine (MDC)/CCL22. Stimulation of hOSCAR acts in conjunction with the Toll-like receptor (TLR) ligands, lipopolysaccharide (LPS), R-848, and polyinosinic-polycytidylic acid (poly(I:C)), to increase the expression of maturation markers, and to modulate cytokine release. A PI3K-dependent up-regulation of IL-10 release is observed with all the TLR ligands used, whereas regulation of IL-12 production is variable depending on the TLR stimulated. hOSCAR engagement on DCs did not significantly increase the proliferation of naive T cells; however, when co-incubated with TLR ligands, an enhanced proliferation was observed. The percentage of interferon (IFN)-gamma-producing T cells is decreased when hOSCAR engagement is combined with LPS stimulation. Altogether, these data suggest that hOSCAR may modulate the responses of both innate resistance and adaptive immunity.     

Human pancreatic precursor cells secrete FGF2 to stimulate clustering into hormone-expressing islet-like cell aggregates

Development of the endocrine pancreas includes a series of early events wherein precursor cells cluster, that is migrate to form cell aggregates, which subsequently differentiate into islets of Langerhans. We show that PANC-1 cells, a human pancreatic cell line, differentiates into hormone-producing islet-like cell aggregates after exposure to a defined serum-free medium. These cells were used to provide the following evidence that fibroblast growth factor (FGF)2 is a paracrine chemoattractant during PANC-1 cell clustering: (i) FGF2 is secreted and remains bound to the extracellular matrix from where it may diffuse to form chemoattractive gradients; (ii) a subset of cells expresses FGF receptors (FGFRs) -1, -2, -3, and -4; (iii) inhibition of FGFR tyrosine kinase inhibits cell clustering; and (iv) FGF2 neutralizing antibody inhibits clustering. In addition, adult human islet-derived precursor cells, which cluster and differentiate in a manner similar to PANC-1 cells, also secrete FGF2 and express FGFRs. We conclude that FGF2, acting as a paracrine chemoattractant, stimulates clustering of precursor cells, an early step leading to islet-like cell aggregate formation. Similar processes may occur during development of the islet of Langerhans in humans.     

Efficacy and safety of fixed combinations of irbesartan/hydrochlorothiazide in older vs younger patients with hypertension uncontrolled with monotherapy

Subgroup analysis of the Irbesartan/Hydrochlorothiazide Blood Pressure Reductions in Diverse Patient Populations (INCLUSIVE) trial evaluated the efficacy and safety of irbesartan/hydrochlorothiazide (HCTZ) fixed combinations in patients aged 65 years or older with uncontrolled systolic blood pressure (SBP) after >or= 4 weeks of antihypertensive monotherapy. The INCLUSIVE trial was a prospective, open-label, single-arm trial carried out in 119 sites. Of 844 patients completing placebo treatment, 212 were aged 65 years or older. Participants received treatment with placebo (4-5 weeks), HCTZ 12.5 mg (2 weeks), irbesartan/HCTZ 150/12.5 mg (8 weeks), and then irbesartan/HCTZ 300/25 mg (8 weeks). From baseline to week 18 (n=184, intent-to-treat population), mean change in SBP was -23.0+/-13.3 mm Hg (P<.001) and diastolic BP (DBP) was -10.9+/-7.7 mm Hg (P<.001). Mean SBP/DBP at study end was 134.0+/-14.7/75.1+/-8.4 mm Hg, and SBP, DBP, and SBP/DBP goal was achieved in 73%, 96%, and 72% of patients, respectively. Irbesartan/HCTZ combination therapy allowed SBP goal attainment in 73% of patients aged 65 years or older whose hypertension was previously uncontrolled with antihypertensive monotherapy.     

N-Terminal Pro–B-Type Natriuretic Peptide in the Emergency Department: The ICON-RELOADED Study

Background

Contemporary reconsideration of diagnostic N-terminal pro–B-type natriuretic peptide (NT-proBNP) cutoffs for diagnosis of heart failure (HF) is needed.

Interventions in labour and birth and satisfaction with care: The Canadian Maternity Experiences Survey Findings

Objective: To examine whether interventions in labour and birth contributed to ratings of satisfaction with these experiences, in women giving birth vaginally or attempting a vaginal birth prior to giving birth by caesarean section. Background: Ratings of satisfaction with women’s overall experience of labour and birth have long been encouraged, yet remain challenging to assess or to interpret. Methods: Data from the Canadian Maternity Experiences Survey (MES) – a nationally representative sample of women who had a singleton live birth in 2005–2006 – were analysed. Associations between the number of and type of labour and birth interventions, and women’s satisfaction with the overall labour and birth experience and six aspects of caregiver interactions, were assessed. Results: Among women having vaginal births, fewer interventions during labour was significantly associated with higher overall satisfaction with the labour and birth experience (ranging from 75% of women having no interventions to 46.4% having eight or more interventions rating their experiences as ‘very postive’). The same pattern was observed for satisfaction with women’s perceptions of caregiver’s respect, concern for dignity, compassion shown to them, the information given to them, their involvement in decision making, and caregiver’s competence. Among women having unplanned caesarean sections following attempted vaginal birth, the number of interventions was not associated with satisfaction ratings; however, satisfaction ratings were consistently lower than among women giving birth vaginally. Conclusion: These findings provide support for demedicalising vaginal labour and birth as well as for optimising the potential for a vaginal birth rather than caesarean section.     

Association of NT-ProBNP,Blood Pressure,and Cardiovascular Events: The ARIC Study

BackgroundAlthough intensive blood pressure reduction has cardiovascular benefits, the absolute benefit is greater in those at higher cardiovascular disease (CVD) risk.ObjectivesThis study examined whether N-terminal pro–B-type natriuretic peptide (NT-proBNP) helps identify subjects at higher risk for CVD events across systolic blood pressure (SBP), diastolic blood pressure (DBP), or pulse pressure (PP) categories.MethodsParticipants from the ARIC (Atherosclerosis Risk In Communities) study visit 4 (1996 to 98) were grouped according to SBP, DBP, or PP categories and further stratified by NT-proBNP categories. Cox regression models were used to estimate hazard ratios for incident CVD (coronary heart disease, ischemic stroke, or heart failure hospitalization) and mortality across combined NT-proBNP and/or BP categories, adjusting for CVD risk factors.ResultsThere were 9,309 participants (age: 62.6 ± 5.6 years; 58.3% women) with 2,416 CVD events over a median follow-up of 16.7 years. Within each SBP, DBP, or PP category, a higher category of NT-proBNP (100 to <300 or 300 pg/ml, compared with NT-proBNP <100 pg/ml) was associated with a graded increased risk for CVD events and mortality. Participants with SBP 130 to 139 mm Hg but NT-proBNP ≥300 pg/ml had a hazards ratio of 3.4 for CVD (95% confidence interval: 2.44 to 4.77) compared with a NT-proBNP of <100 pg/ml and SBP of 140 to 149 mm Hg.ConclusionsElevated NT-proBNP is independently associated with CVD and mortality across SBP, DBP, and PP categories and helps identify subjects at the highest risk. Participants with stage 1 hypertension but elevated NT-proBNP had greater cardiovascular risk compared with those with stage 2 SBP but lower NT-proBNP. Future studies are needed to evaluate use of biomarker-based strategies for CVD risk assessment to assist with initiation or intensification of BP treatment.