Atovaquone-Proguanil Remains a Potential Stopgap Therapy for Multidrug-Resistant Plasmodium falciparum in Areas along the Thai-Cambodian Border

Our recent report of dihydroartemisinin-piperaquine failure to treat Plasmodium falciparum infections in Cambodia adds new urgency to the search for alternative treatments. Despite dihydroartemisinin-piperaquine failure, and higher piperaquine 50% inhibitory concentrations (IC₅₀s) following reanalysis than those previously reported, P. falciparum remained sensitive to atovaquone (ATQ) in vitro. There were no point mutations in the P. falciparum cytochrome b ATQ resistance gene. Mefloquine, artemisinin, chloroquine, and quinine IC₅₀s remained comparable to those from other recent reports. Atovaquone-proguanil may be a useful stopgap but remains susceptible to developing resistance when used as blood-stage therapy.     

The use of the hydrodynamic HBV animal model to study HBV biology and anti-viral therapy.

A simple reproducible and versatile small animal model for hepatitis B virus (HBV) infection is still unavailable. We have generated a simple transient liver-targeted transgenic mouse. Hydrodynamics tail vein injection of a head-to-tail dimer of adw HBV genome (pHBVadwHTD) into immunocompetent mice generated HBsAg and HBeAg expression in both serum and hepatocytes, followed by seroconversion. The injection of pHBVadwHTD into SCID mice generated prolonged HBsAg and HBeAg antigenemia and HBV viremia. Our results demonstrate that hydrodynamic injection of naked DNA could support the generation of HBV particles. We used this model for the assessment of anti-viral agents. Administration of our human monoclonal antibodies, HBV-Ab17(XTL) and HBV-Ab19(XTL), as well as Lamivudine (3TC) treatment suppressed HBV viremia. The model presented herein supports long and stable expression of HBV and will enable determination of various biological questions related to HBV life cycle, mutants and could enhance the development of anti-viral reagents.     

The urinary steroid profile in patients diagnosed with adrenal incidentaloma

Objective

The aim of this study was to investigate the possible urinary markers of hormonal activity in patients with non-functioning adrenal incidentalomas. In order to evaluate the endocrine activity of forementioned tumours, urinary steroid metabolite levels were analyzed in samples from patients and controls. Possible blocks in metabolic pathways of the examined hormones were determined by comparing selected urinary steroid metabolite sums and ratios in both groups of interest.

Design

Urine samples were collected from 20 patients with non-functioning adrenal incidentalomas and from 25 controls matched in terms of age, sex and BMI. Excretion of 19 major urinary steroid metabolites was analyzed by gas chromatography. The results were subjected to statistical analysis.

Results

In patients with adrenal incidentalomas sum of total urinary cortisol metabolites was significantly increased in respect to the control group. We also observed a shift towards tetrahydrocorticosterone, cortisol and etiocholanolone production in patients. No significant differences in production of other urinary steroid metabolites were noted in patients with adrenal incidentalomas in respect to control group.

Conclusions

Our data suggests that not only urinary free cortisol but also its metabolite such as tetrahydrocortisol and other steroids including etiocholanolone and corticosterone tetrahydrometabolite might be urinary markers for the endocrine activity of adrenal incidentalomas. Enhanced levels of these urinary steroid metabolites indicate an impairment of 11β-hydroxysteroid dehydrogenase activity and slightly increased activity of 5β-reductase in patients with adrenal incidentalomas.     

Characteristics of patients receiving vasopressors

Background

Patients receiving intensive care frequently need pharmacologic support of their blood pressure because of shock. In some patients, shock is so severe that extremely high doses of vasopressors are needed to elevate their blood pressure.

Objective

We sought to ascertain the maximal dose of vasopressors administered to patients, and to describe the population of patients receiving vasopressors in one intensive care unit.

Methods

All adult patients admitted in 2001 to a 10-bed surgical unit in a university hospital, and receiving a vasopressor agent for 1 hour or more, underwent recordings of their demographic data, diagnoses upon admission, Acute Physiological and Chronic Health Evaluation (APACHE) II scores, vasopressors (including type, initial dose, dose increases, and maximal dose), number of days administered, complications, and mortality.

Results

Of 689 patients whose charts were reviewed, 72 received vasopressors. The mean age was 65 ± 21.4 years, and 66% were male. The mean APACHE II scores were 24 ± 6.2. The administration of .5 μg/kg/minute of norepinephrine or epinephrine resulted in 96% sensitivity and a specificity of 76% for the likelihood of mortality. Using Kaplan-Meyer curves, those patients receiving less than .5 μg/kg/minute demonstrated an 80% 6-year survival. All 17 patients receiving more than 3.8 μg/kg/minute of norepinephrine, and all 5 patients receiving more than 9.6 μg/kg/minute of epinephrine, died. The length of time during which patients received less than their maximal dose of vasopressors had no influence on survival (P = .4). The elderly (aged ≥75 years) and the young (aged <75 years) had the same intensive care unit survival rates when receiving vasopressors.

Conclusion

In this study, little likelihood of intensive care unit survival was evident when patients received more than .5 μg/kg/minute of norepinephrine or epinephrine.     

Novel risk factors for peripheral arterial disease in young women

PURPOSE: To investigate traditional and novel risk factors (homocysteine and C-reactive protein levels, and exposure to infections) for peripheral arterial disease in young women. SUBJECTS AND METHODS: In a multicenter, population-based, case-control study, 212 young women (mean [+/- SD] age, 48.2 +/- 7.0 years) with peripheral arterial disease and 475 healthy control women (mean age, 45.5 +/- 8.1 years) completed a standardized questionnaire and provided blood samples. Peripheral arterial disease was angiographically confirmed if a stenotic lesion (more than 50% reduction of the lumen) was present in at least one major peripheral artery. Hyperhomocysteinemia was defined as a nonfasting plasma homocysteine level exceeding the 90th percentile of the control group. History of infectious diseases was determined by questionnaire. RESULTS: Elevated C-reactive protein levels were associated with an increased likelihood of peripheral arterial disease (odds ratio [OR] = 3.9; 95% confidence interval [CI]: 1.8 to 8.5 for women in the third quartile; OR = 3.1; 95% CI: 1.4 to 6.8 for women in the fourth quartile; both comparisons with women in the first quartile). Hyperhomocysteinemia was not associated with a significantly increased risk of peripheral arterial disease (OR = 1.6; 95% CI: 0.9 to 3.0). A history of chickenpox, shingles, mumps, pneumonia, chronic bronchitis, peptic ulcer, or periodontitis was independently related to peripheral arterial disease, with adjusted odds ratios varying from 1.7 (95% CI: 1.0 to 3.1) for mumps to 3.4 (95% CI: 1.5 to 7.7) for peptic ulcer. The risk of peripheral arterial disease increased with the number of these infections; exposure to five or more infections increased the odds 3.7-fold (95% CI: 1.7 to 8.2). This association was not affected by the level of C-reactive protein. CONCLUSION: Our results do not support a strong relation between homocysteine and peripheral arterial disease in young women. However, an elevated C-reactive protein level and several types of symptomatic infection were associated with peripheral arterial disease.     

Carriage of methicillin-resistant Staphylococcus aureus on admission to European rehabilitation centres--a prospective study

This study aimed to determine the prevalence of and risk factors for methicillin-resistant Staphylococcus aureus (MRSA) carriage among patients newly admitted to rehabilitation centres. It is a prospective study examining MRSA carriage on admission to seven rehabilitation wards in four countries. Risk factors for MRSA carriage were analysed using univariate and multivariate analyses. A total of 1204 patients were studied. Among them, 105 (8.7%) had a positive admission MRSA screening result. The MRSA carriers were more likely to be male, to have had a recent stay in another long-term-care facility or >2 weeks acute-care hospital stay, history of colonization with MRSA, reduced level of consciousness, peripheral vascular disease and pressure sores. In multivariable logistic regression male gender (odds ratio (OR) 2.2, 95% confidence interval (CI) 1.4-3.6, p 0.001), history of MRSA positivity (OR 6.8, 95% CI 3.8-12.3, p <0.001), peripheral vascular disease (OR 2.5, 95% CI 1.2-5, p 0.013), recent stay in another long-term-care facility (OR 2.1, 95% CI 1.3-3.5, p 0.004), or long (>2 weeks) acute-care hospital stay (OR 1.9, 95% CI 1.2-3, p 0.004), remained significant risk factors for MRSA carriage. MRSA carriage is common on admission to rehabilitation centres but less so, than previously described in long-term-care facilities. Male gender, history of MRSA positivity, previous hospitalization and peripheral vascular disease may predict MRSA carriage, and may serve as indicators for using pre-emptive infection control measures.     

A case of postpartum eosinophilic gastroenteritis and review of the literature

Eosinophilic gastroenteritis (EG) is a rare disease of unknown etiology that can involve any area of the gastrointestinal (GI) tract. It can be classified into three major types: predominantly mucosal, muscularis, or subserosal form. Diagnosis of EG is confirmed after the exclusion of other disorders having similar features, such as parasitic infection, carcinoma, allergy, and autoimmune conditions such as Churg-Strauss disease. Correct diagnosis hinges on the presence of eosinophilic infiltration of one or more areas of the GI tract, without extraintestinal involvement. We present the case of a 30-year-old female with symptoms of EG 26 days after delivery. After corticosteroid and montelukast treatment for 2 weeks, all symptoms and objective clinical findings disappeared. Although numerous cases of this disorder have been described, to our knowledge this is the first case of postpartum EG. This case highlights the need to include this entity in the differential diagnosis of postpartum GI disorders.     

Diverse innate stimuli activate basophils through pathways involving Syk and IκB kinases

Mature basophils play critical inflammatory roles during helminthic, autoimmune, and allergic diseases through their secretion of histamine and the type 2 cytokines interleukin 4 (IL-4) and IL-13. Basophils are activated typically by allergen-mediated IgE cross-linking but also by endogenous “innate” factors. The aim of this study was to identify the innate stimuli (cytokines, chemokines, growth factors, hormones, neuropeptides, metabolites, and bacterial products) and signaling pathways inducing primary basophil activation. Basophils from naïve mice or helminth-infected mice were cultured with up to 96 distinct stimuli and their influence on basophil survival, activation, degranulation, and IL-4 or IL-13 expression were investigated. Activated basophils show a heterogeneous phenotype and segregate into distinct subsets expressing IL-4, IL-13, activation, or degranulation markers. We find that several innate stimuli including epithelial derived inflammatory cytokines (IL-33, IL-18, TSLP, and GM-CSF), growth factors (IL-3, IL-7, TGFβ, and VEGF), eicosanoids, metabolites, TLR ligands, and type I IFN exert significant direct effects on basophils. Basophil activation mediated by distinct upstream signaling pathways is always sensitive to Syk and IκB kinases-specific inhibitors but not necessarily to NFAT, STAT5, adenylate cyclase, or c-fos/AP-1 inhibitors. Thus, basophils are activated by very diverse mediators, but their activation seem controlled by a core checkpoint involving Syk and IκB kinases.

Basophils are rare circulating granulocytes activated by immunoglobulin E (IgE)-mediated cross-linking of the high affinity receptor for IgE (FcεRI), which induces their degranulation and synthesis of the type 2 cytokines, interleukin 4 (IL-4) and IL-13 in autoimmune, allergic diseases and helminthiases (1). Basophils are also sensitive to innate signals, including the cytokine IL-3, the alarmins IL-18, IL-33, and Thymic stromal Lymphopoietin (TSLP), the prostaglandin D2 (PGD2), ATP, and various chemokines or growth factors (1–4). Some of these stimuli might regulate basophil immunoregulatory functions during homeostasis (5). Secretion of IL-4 and histamine release by human basophils is sensitive to FK506 (a calcineurin inhibitor), while secretion of IL-13 is not affected, indicating that distinct signaling pathways regulate the expression of these type 2 cytokines (6–8). By contrast, activation of basophils by IgE or IL-18/33 involves distinct receptors and upstream signaling pathways but results in expression of both IL-4 and IL-13 (5, 7, 9–11). Despite common evolutionary ancestry, it is currently thought that IL-4 and IL-13 show divergent functions in immunity and physiology (12, 13). Basophil IL-4 secretion has been implicated in T helper type 2 (Th2) differentiation and M2 skewing. Basophils are an important source of IL-13 in the lungs, where they control the phenotype of alveolar macrophages during development (1, 5).The Il4/13 locus is subject to a differential regulation between distinct cell types but has been mostly studied in T cells. The locus contains elements regulated by cAMP, c-fos/AP-1, NFAT, NF-κB, GATA3, STAT5, and STAT6 that have been associated with the regulation of Il4/13 expression (6, 14–19). Basophils produce IL-4 and IL-13 after the cross-linking of their surface-bound IgE by antigen or by exposure to IL-3. IgE- or IL-3-mediated basophil activation are both controlled by the tyrosine kinase Syk (6, 20, 21). IgE-induced cytokine expression is also promoted by IκB kinase (IKK) through NF-κB-dependent or -independent signals (22, 23).To date, studies of murine basophils have focused on cultured bone marrow-derived basophils (BMBa) or primary bone marrow (BM) basophils, with circulating mature basophils too few in number for useful studies (6). We used B8 × 4C13R IL-4/IL-13 triple reporter mice (24) to follow and compare the ex vivo responses of primary mature basophils to 96 common stimuli and found that basophils were highly sensitive to type 2 and epithelial-derived cytokines and growth factors. Single-cell analysis revealed that basophils displayed distinct phenotypes upon stimulation with IL-3, expressing IL-4, and/or IL-13, Ly6C, or the degranulation marker CD63 (25). During helminth infection, basophils were found to be hyper- and hyporeactive to distinct stimuli (“Hp-basophils”). Purified Hp-basophils were also sensitive to homeostatic growth factors and antiviral response elements. Basophil reactivity was always sensitive to Syk and IKKs specific inhibitors. In conclusion, we found basophils to be sensitive to a complex array of distinct innate stimuli that worked through core common signaling pathways.