European hares in Chile: a different lagomorph reservoir for Mycobacterium avium subsp. paratuberculosis?

Ruminants are the principal host for infection by Mycobacterium avium subsp. paratuberculosis (Map), the cause of Johne's disease. Based on studies of a Map-infected population of European rabbits (Oryctolagus cuniculus) in Scotland, lagomorphs as a broad taxonomic order were proposed as potential nonruminant reservoirs for Map. To determine whether a different lagomorph species may serve as a wildlife reservoir, we investigated Map infection in European hares (Lepus europaeus) sharing habitat with known Map-infected dairy cattle in southern Chile. Fecal, mesenteric lymph node, and ileal samples were aseptically collected from 385 wild hares for liquid culture and real-time polymerase chain reaction identification of acid-fast isolates. All tissue samples were also acid-fast stained and examined microscopically. We isolated Map from at least one tissue from 48 hares (12.6%) and fecal samples from 16 hares (4.2%). No Map was found in tissues of eight of the fecal-culture-positive hares. Histologically, all tissues from all hares were within normal limits, and no acid-fast organisms were observed in any sample. Active infection, implying amplification of the organism secondary to resultant disease, was not evident. With this report Map isolations on a population versus incidental detection have now been made from two lagomorph species. However, although the rabbit population studied in Scotland appears to function as a Map reservoir, the hares studied in Chile appear to be a dead-end host, serving only as potential mechanical vectors for the organism.     

Switching to basal-bolus insulin therapy is effective and safe in long-term type 2 diabetes patients inadequately controlled with other insulin regimens

AimTo assess in standard clinical practice the feasibility, efficacy, and safety of switching patients with long-standing type 2 diabetes (T2DM) and poor or unstable blood glucose control to basal-bolus insulin therapy.Material and methodsThis was a prospective, single center study including 37 patients with T2DM (age 65 ± 8 years, 62.2% men, body mass index 28.8 ± 6.2 kg/m², diabetes duration 18 ± 8 years) with poor or unstable glycemic control, who were switched to a basal-bolus insulin regimen with glargine and rapid-acting insulin analogue at the discretion of their physicians. After a group-structured outpatient diabetes training program, patients were followed in a clinical practice setting for 6 months. Clinical and biochemical variables were collected before switching and at 3 and 6 months.ResultsAfter switching to basal-bolus therapy, glycosylated hemoglobin (HbA1c) decreased from 9 ± 1.2% to 8.1 ± 1.2% (p < 0.001) at 3 months and to 8.0 ± 1.2% at 6 months (p < 0.001) without changing total daily insulin dose. The proportion of patients with HbA1c ≥ 9% decreased from 51% to 13.8% at 3 months and to 18.9% at 6 months respectively. There was a single episode of severe hypoglycemia. No changes were seen in body weight and quality of life. The size of LDL (low density lipoprotein) particles significantly increased at 3 and 6 months, while all other lipid parameters remained unchanged.ConclusionsOur study confirmed that basal-bolus insulin therapy is feasible, effective, and safe in patients with long-standing T2DM, and does not impair their quality of life.     

Mice Long-Term High-Fat Diet Feeding Recapitulates Human Cardiovascular Alterations: An Animal Model to Study the Early Phases of Diabetic Cardiomyopathy

Background/Aim

Hypercaloric diet ingestion and sedentary lifestyle result in obesity. Metabolic syndrome is a cluster of clinical features secondary to obesity, considered as a pre-diabetic condition and recognized as an independent risk factor for cardiovascular diseases. To better understand the relationship between obesity, metabolic syndrome and cardiovascular disease as well as for the development of novel therapeutic strategies, animal models that reproduce the etiology, course and outcomes of these pathologies are required. The aim of this work was to characterize the long-term effects of high-fat diet-induced obesity on the mice cardiovascular system, in order to make available a new animal model for diabetic cardiomyopathy.

Methods/Results

Male C57BL/6 mice were fed with a standardized high-fat diet (obese) or regular diet (normal) for 16 months. Metabolic syndrome was evaluated testing plasma glucose, triglycerides, cholesterol, insulin, and glucose tolerance. Arterial pressure was measured using a sphygmomanometer (non invasive method) and by hemodynamic parameters (invasive method). Cardiac anatomy was described based on echocardiography and histological studies. Cardiac function was assessed by cardiac catheterization under a stress test. Cardiac remodelling and metabolic biomarkers were assessed by RT-qPCR and immunoblotting. As of month eight, the obese mice were overweight, hyperglycaemic, insulin resistant, hyperinsulinemic and hypercholesterolemic. At month 16, they also presented normal arterial pressure but altered vascular reactivity (vasoconstriction), and cardiac contractility reserve reduction, heart mass increase, cardiomyocyte hypertrophy, cardiac fibrosis, and heart metabolic compensations. By contrast, the normal mice remained healthy throughout the study.

Conclusions

Mice fed with a high-fat diet for prolonged time recapitulates the etiology, course and outcomes of the early phases of human diabetic cardiomyopathy.     

Insulin-stimulated L-arginine transport requires SLC7A1 gene expression and is associated with human umbilical vein relaxation

Insulin causes endothelium‐derived nitric oxide (NO)‐dependent vascular relaxation, and increases L ‐arginine transport via cationic amino acid transporter 1 (hCAT‐1) and endothelial NO synthase (eNOS) expression and activity in human umbilical vein endothelium (HUVEC). We studied insulin effect on SLC7A1 gene (hCAT‐1) expression and hCAT‐transport activity role in insulin‐modulated human fetal vascular reactivity. HUVEC were used for L ‐arginine transport and L ‐[³H]citrulline formation (NOS activity) assays in absence or presence of N‐ethylmaleimide (NEM) or L ‐lysine (L ‐arginine transport inhibitors). hCAT‐1 protein abundance was estimated by Western blot, mRNA quantification by real time PCR, and SLC7A1 promoter activity by Luciferase activity (?1,606 and ?650 bp promoter fragments from ATG). Specific protein 1 (Sp1), and total or phosphorylated eNOS protein was determined by Western blot. Sp1 activity (at four sites between ?177 and ?105 bp from ATG) was assayed by chromatin immunoprecipitation (ChIP) and vascular reactivity in umbilical vein rings. Insulin increased hCATs–L ‐arginine transport, maximal transport capacity (V_max/K_m), and hCAT‐1 expression. NEM and L ‐lysine blocked L ‐arginine transport. In addition, it was trans‐stimulated (～7.8‐fold) by L ‐lysine in absence of insulin, but unaltered (～1.4‐fold) in presence of insulin. Sp1 nuclear protein abundance and binding to DNA, and SLC7A1 promoter activity was increased by insulin. Insulin increased NO synthesis and caused endothelium‐dependent vessel relaxation and reduced U46619‐induced contraction, effects blocked by NEM and L ‐lysine, and dependent on extracellular L ‐arginine. We suggest that insulin induces human umbilical vein relaxation by increasing HUVEC L ‐arginine transport via hCATs (likely hCAT‐1) most likely requiring Sp1‐activated SLC7A1 expression. J. Cell. Physiol. 226: 2916–2924, 2011. © 2011 Wiley‐Liss, Inc.     

Radiative and Non-radiative Surface Plasmon Resonance: Comparison of Real-Time Sensing Performance

Plasmonics - The work presents a surface plasmon resonance sensor able to operate the non-radiative and radiative surface plasmons simultaneously. The optical coupling between photons and surface...     

Web-based virtual microscopy for parasitology: a novel tool for education and quality assurance

Background

The basis for correctly assessing the burden of parasitic infections and the effects of interventions relies on a somewhat shaky foundation as long as we do not know how reliable the reported laboratory findings are. Thus virtual microscopy, successfully introduced as a histopathology tool, has been adapted for medical parasitology.

Methodology/Principal Findings

Specimens containing parasites in tissues, stools, and blood have been digitized and made accessible as a “webmicroscope for parasitology” (WMP) on the Internet (http://www.webmicroscope.net/parasitology).These digitized specimens can be viewed (“navigated” both in the x-axis and the y-axis) at the desired magnification by an unrestricted number of individuals simultaneously. For virtual microscopy of specimens containing stool parasites, it was necessary to develop the technique further in order to enable navigation in the z plane (i.e., “focusing”). Specimens were therefore scanned and photographed in two or more focal planes. The resulting digitized specimens consist of stacks of laterally “stiched” individual images covering the entire area of the sample photographed at high magnification. The digitized image information (∼10 GB uncompressed data per specimen) is accessible at data transfer speeds from 2 to 10 Mb/s via a network of five image servers located in different parts of Europe. Image streaming and rapid data transfer to an ordinary personal computer makes web-based virtual microscopy similar to conventional microscopy.

Conclusion/Significance

The potential of this novel technique in the field of medical parasitology to share identical parasitological specimens means that we can provide a “gold standard”, which can overcome several problems encountered in quality control of diagnostic parasitology. Thus, the WMP may have an impact on the reliability of data, which constitute the basis for our understanding of the vast problem of neglected tropical diseases. The WMP can be used also in the absence of a fast Internet communication. An ordinary PC, or even a laptop, may function as a local image server, e.g., in health centers in tropical endemic areas.     

Copper interaction on the long-term potentiation

The role of copper on the CA1 piramidal neurons and their sinaptic connections to the Schaffer's collateral was investigated using the field excitatory post-sinaptic potential (fEPSP). The same fEPSP was used to study copper effects on Long-term potentiation (LTP). We have found that copper 10 microM has an inhibitory action on the fEPSP. Similar effects were demonstrated with 10 microM of GABA. Moreover, copper showed a strong inhibitory action on the consolidated LTP. However, copper washout left a significant and persistent excitatory response. In our opinion, copper shows a dual sinaptic effect depending on the sinaptic experience.     

Nitric oxide and pH modulation in gynaecological cancer

Nitric oxide plays several roles in cellular physiology, including control of the vascular tone and defence against pathogen infection. Neuronal, inducible and endothelial nitric oxide synthase (NOS) isoforms synthesize nitric oxide. Cells generate acid and base equivalents, whose physiological intracellular concentrations are kept due to membrane transport systems, including Na⁺/H⁺ exchangers and Na⁺/HCO₃^? transporters, thus maintaining a physiological pH at the intracellular (~7.0) and extracellular (~7.4) medium. In several pathologies, including cancer, cells are exposed to an extracellular acidic microenvironment, and the role for these membrane transport mechanisms in this phenomenon is likely. As altered NOS expression and activity is seen in cancer cells and because this gas promotes a glycolytic phenotype leading to extracellular acidosis in gynaecological cancer cells, a pro‐inflammatory microenvironment increasing inducible NOS expression in this cell type is feasible. However, whether abnormal control of intracellular and extracellular pH by cancer cells regards with their ability to synthesize or respond to nitric oxide is unknown. We, here, discuss a potential link between pH alterations, pH controlling membrane transport systems and NOS function. We propose a potential association between inducible NOS induction and Na⁺/H⁺ exchanger expression and activity in human ovary cancer. A potentiation between nitric oxide generation and the maintenance of a low extracellular pH (i.e. acidic) is proposed to establish a sequence of events in ovarian cancer cells, thus preserving a pro‐proliferative acidic tumour extracellular microenvironment. We suggest that pharmacological therapeutic targeting of Na⁺/H⁺ exchangers and inducible NOS may have benefits in human epithelial ovarian cancer.