Detection of Extended-Spectrum-β-Lactamase-Producing Escherichia coli ST131 and ST405 Clonal Groups by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

Escherichia coli sequence type 131 (ST131) and ST405 are important clonal groups, because they are associated with the global increase of extended-spectrum-β-lactamase (ESBL) producers. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) is emerging as a rapid, inexpensive, and accurate method for bacterial identification. We investigated the detection performance of MALDI-TOF for the ST131 and ST405 clonal groups using 41 ST131-O25b, 26 ST131-O16, and 41 ST405 ESBL-producing isolates and 41 ESBL-producing isolates frrom other STs. The main spectra representing each clonal group were used for classification with Biotyper (Bruker Daltonics GmbH, Bremen, Germany). The peak that had the highest area under the receiver-operating characteristic curve generated by ClinProTools (Bruker) was detected with FlexAnalysis (Bruker), and an optimal signal-to-noise ratio cutoff was determined. The optimal detection models were generated by ClinProTools. Classification by Biotyper could detect the ST131-whole (O25b and O16 together) group with a sensitivity of 98.5% and a specificity of 93.9%. With FlexAnalysis, a peak of 9,720 Da detected the ST131-whole group with a sensitivity of 97.0% and a specificity of 91.5% at a cutoff value of 8.0. The ClinProTools models exhibited good performance for the detection of the ST131-whole group (sensitivity and specificity, 94.0% and 92.7%, respectively), the ST131-O25b group (95.1% and 98.2%, respectively), and the ST405 group (90.2% and 96.3%, respectively). MALDI-TOF MS had high detection performance for the ST131-whole, ST131-O25b, and ST405 clonal groups. MALDI-TOF MS should be considered as an alternative method to monitor the epidemiology of the ESBL-producing E. coli ST131 and ST405 clonal groups.     

Intravenous IgA complexed with antigen reduces primary antibody response to the antigen and anaphylaxis upon antigen re-exposure by inhibiting Th1 and Th2 activation in mice

Context: Serum IgG, IgE and IgM have been shown to enhance the primary antibody responses upon exposure to the soluble antigens recognized by those antibodies. However, how IgA affects these responses remains unknown.

Objective: We investigated the effects of intravenously administered monoclonal IgA on the immune responses in mice.

Materials and methods: DBA/1J mice were immunized with ovalbumin in the presence or absence of anti-ovalbumin monoclonal IgA. The Th1 and Th2 immune responses to ovalbumin and the anaphylaxis induced by re-exposure to ovalbumin were measured.

Results: IgA complexed with antigen attenuated the primary antibody responses to the antigen in mice, in contrast to IgG2b and IgE. The primary antibody responses, i.e. the de novo synthesis of anti-ovalbumin IgG2a, IgG1 and IgE in the serum, and the subsequent anaphylaxis induced with re-exposure to ovalbumin were reduced by the co-injection of anti-ovalbumin monoclonal IgA at ovalbumin immunization. The Th1, Th2 and Tr1 cytokines interferon-γ, interleukin-4 and interleukin-10, respectively, released from ovalbumin-restimulated cultured splenocytes collected from allergic mice were also reduced by the treatment. The induction of interferon-γ and interleukin-4 secretion by splenocytes from ovalbumin-immunized mice stimulated in vitro with ovalbumin was also significantly reduced by the antigen complexed with anti-ovalbumin IgA.

Conclusion: These data suggest that the direct inhibition of Th1 and Th2 activation by anti-ovalbumin monoclonal IgA participates in the inhibition of the primary antibody responses. IgA plays important immunosuppressive roles under physiological and pathological conditions and is a promising candidate drug for the treatment of immune disorders.     

Apelin Inhibits Diet-Induced Obesity by Enhancing Lymphatic and Blood Vessel Integrity

Angiogenesis is tightly associated with the outgrowth of adipose tissue, leading to obesity, which is a risk factor for type 2 diabetes and hypertension, mainly because expanding adipose tissue requires an increased nutrient supply from blood vessels. Therefore, induction of vessel abnormality by adipokines has been well-studied, whereas how altered vascular function promotes obesity is relatively unexplored. Also, surviving Prox1 heterozygous mice have shown abnormal lymphatic patterning and adult-onset obesity, indicating that accumulation of adipocytes could be closely linked with lymphatic function. Here, we propose a new antiobesity strategy based on enhancement of lymphatic and blood vessel integrity with apelin. Apelin knockout (KO) mice fed a high-fat diet (HFD) showed an obese phenotype associated with abnormal lymphatic and blood vessel enlargement. Fatty acids present in the HFD induced hyperpermeability of endothelial cells, causing adipocyte differentiation, whereas apelin promoted vascular stabilization. Moreover, treatment of apelin KO mice with a selective cyclooxygenase-2 inhibitor, celecoxib, that were fed an HFD improved vascular function and also attenuated obesity. Finally, apelin transgenic mice showed decreased subcutaneous adipose tissue attributable to inhibition of HFD-induced hyperpermeability of vessels. These results indicate that apelin inhibits HFD-induced obesity by enhancing vessel integrity. Apelin could serve as a therapeutic target for treating obesity and related diseases.Obesity appears to be associated with a combination of genetic susceptibility, increased consumption of high-energy foods, and decreased physical activity, leading to excessive accumulation of white adipose tissues that serve to store surplus energy in the form of lipid within adipocytes (1). It is correlated with type 2 diabetes, cardiovascular disease, and certain types of cancer, and therefore represents a serious public health problem. Although the molecular mechanisms underlying obesity have not been fully clarified, effective therapeutic approaches are needed.The blood and lymphatic systems are composed of dense networks of capillaries. Blood vessels are indispensable to import and carry fluid, dissolved proteins, and cells into interstitial space, whereas lymphatic vessels drain protein-rich lymph and traffic immune cells from the extracellular space (2). Adipose tissue is mainly composed of adipocytes surrounded by stromal vascular tissue. The balance of adipokine production is disrupted by excess adipose tissue, leading to chronic vascular inflammation, which in turn may lead to cardiovascular disease (3). The outgrowth of adipose tissue is tightly correlated with angiogenesis (4). Thus, antiangiogenesis therapy has emerged as a potential treatment of obesity. However, this idea remains controversial not only because angiogenesis is physiologically important but also because brown adipose tissue consumes more energy if angiogenesis is increased (5). Moreover, there is an increasing emphasis on lymphatic function in obesity research. Chy mice, a naturally occurring mouse model of lymphedema attributable to heterozygous inactivating mutations in vascular endothelial growth factor receptor (VEGFR)-3, exhibit adipose layer accumulation (6). Also, surviving Prox1 heterozygous mice show abnormal lymphatic patterning and adult-onset obesity (7). Thus, accumulation of adipocytes could be closely linked with the structure and function of lymphatic vessels. However, little is known about how vessel integrity influences adipocyte dynamics.The apelin gene encodes a 77-amino-acid preprotein, which is cleaved to shorter active peptides that bind to the apelin receptor (APJ), a G-protein-coupled receptor (8). The full-length mature peptide comprises 36 amino acids (apelin-36), and other active fragments, including a 13-amino-acid peptide known as apelin-13, also are formed. Apelin is expressed widely in the vascular endothelium and acts both locally and via endocrine signaling to activate APJ, which is expressed in cardiomyocytes, endothelial cells, and vascular smooth muscle cells (9). Apelin/APJ signaling is located downstream of angiopoietin-1/Tie2 signaling in endothelial cells (10). Apelin transgenic mice develop enlarged, but not leaky, blood vessels in ischemia, leading to functional recovery (11). More recently, we have shown that apelin attenuates edema formation and inflammation by promoting lymphatic function in vivo (12).Herein, we show that the apelin/APJ system enhances the integrity of lymphatic and blood vessels exposed to dietary fatty acids, resulting in inhibition of high-fat diet (HFD)-induced obesity. These results suggest that apelin may be a new therapeutic target in the treatment of obesity and its related diseases.     

Serum leptin level mediates the association of body composition and serum C-reactive protein in HIV-infected persons on antiretroviral therapy

Higher body mass index (BMI) is associated with increased serum C-reactive protein (CRP) levels in HIV-infected individuals on antiretroviral therapy (ART), but the relationship of adipose tissue mass to systemic inflammation is not well described in this population. We hypothesized that serum adipokine levels (i.e., hormones produced by adipocytes) are a superior predictor of CRP compared to anthropometric or radiographic measures of body composition in patients on effective, stable ART. We evaluated the relationship of serum leptin, adiponectin, and resistin, BMI, and dual energy x-ray absorptiometry (DEXA) measurements with serum highly sensitive CRP (hsCRP) in a cross-sectional cohort of 106 predominantly virologically suppressed, HIV-infected adults on ART for ≥24 weeks using multivariable linear regression and formal criteria to assess statistical mediation. Median BMI, hsCRP, and leptin values were 25.2?kg/m(2), 3.0?mg/liter, and 3.8?ng/ml, respectively. BMI and DEXA limb fat, body fat, and trunk fat measurements were significantly associated with both serum leptin and hsCRP levels (all p≤0.02). Leptin was also associated with hsCRP (p<0.01). The regression coefficient for the effect of BMI or DEXA measurements on hsCRP was reduced, and the relationship was no longer statistically significant, after adjusting for leptin, indicating leptin functioned as a mediating variable within these relationships. Adiponectin and resistin levels did not demonstrate similar effects. Serum leptin was a superior predictor of hsCRP compared to BMI and DEXA body fat measurements, which may reflect alterations in body composition in treated HIV infection and the important contribution of adipose tissue to inflammation in this population.     

Efficacy and safety of the pterional keyhole approach for the treatment of anterior circulation aneurysms

Keyhole surgery is partly replacing the standard pterional approach in patients undergoing surgery to treat aneurysms of the anterior circulation. We describe the pterional keyhole approach for the clipping of anterior circulation aneurysms and discuss the efficacy and safety of our keyhole craniotomy procedure. We treated 103 patients with 111 intracranial aneurysms by surgical clipping via the pterional keyhole approach and retrospectively compared the characteristics and clinical outcomes of the keyhole procedure and the standard pterional approach. We also compared the surgical results of the keyhole approach when the operator was an experienced neurosurgeon or a less experienced neurosurgeon guided by an experienced colleague. All keyhole operations were carried out successfully without enlargement of the craniotomy or a change to a different approach. The outcomes of the keyhole and the standard pterional approach in patients with subarachnoid hemorrhage were not significantly different. Favorable outcomes were obtained in patients with unruptured aneurysms treated by either experienced or less experienced surgeons. The pterional keyhole approach offers the same surgical possibilities as conventional pterional approaches for the treatment of anterior circulation aneurysms. It is safe and simple and yields favorable outcomes even if the operators are less experienced neurosurgeons. Careful patient selection and sufficient opening of the sylvian fissure are the key points for good outcomes and the prevention of intraoperative complications.