Multiple Strains of Coxiella burnetii are Present in the Environment of St. Paul Island,Alaska

In 2010, Coxiella burnetii was identified at a high prevalence in the placentas of Northern fur seals (Callorhinus ursinus) collected at a single rookery on St. Paul Island Alaska; an area of the United States where the agent was not known to be present. As contamination was hypothesized as a potential cause of false positives, but nothing was known about environmental C. burnetii in the region, an environmental survey was conducted to look for the prevalence and distribution of the organism on the island. While environmental prevalence was low, two strains of the organism were identified using PCR targeting the COM1 and IS1111 genes. The two strains are consistent with the organism that has been increasingly identified in marine mammals as well as a strain type more commonly found in terrestrial environments and associated with disease in humans and terrestrial animals. Further work is needed to elucidate information regarding the ecology of this organism in this region, particularly in association with the coastal environment.     

Decision-support models for empiric antibiotic selection in Gram-negative bloodstream infections

Objectives

Early empiric antibiotic therapy in patients can improve clinical outcomes in Gram-negative bacteraemia. However, the widespread prevalence of antibiotic-resistant pathogens compromises our ability to provide adequate therapy while minimizing use of broad antibiotics. We sought to determine whether readily available electronic medical record data could be used to develop predictive models for decision support in Gram-negative bacteraemia.

Primary Stroke in a Woman With Sickle Cell Anemia Responsive to Hydroxyurea Therapy

The most common cause of stroke in children with sickle cell anemia is infarction due to ischemia. In adults, however, stroke is most commonly hemorrhagic in nature. Other causes of stroke in patients with sickle cell disease are very rare. In this short communication, we describe a woman with sickle cell anemia responsive to hydroxyurea (HU) therapy who had primary stroke due to paradoxical embolization caused by a large atrial septal defect. Successful management of the stroke included surgical closure of the defect with trans-esophageal echocardiographic guidance. To the best of our knowledge, this is the first patient with sickle cell anemia and stroke due to congenital heart disease who did not require open heart surgery for successful management.     

Stabilizing effect of exenatide in a patient with C‐peptide‐negative diabetes mellitus

Background Exenatide is an incretin mimetic licensed for treatment of Type 2 diabetes poorly controlled despite maximally tolerated doses of oral therapy. Similar in structure to the natural incretin hormone glucagon‐like peptide 1 (GLP‐1), it helps restore underlying pathophysiological abnormalities. Case report We report the successful use of exenatide, combined with insulin, in a 66‐year‐old woman initially diagnosed with Type 2 diabetes in 1989 but now exhibiting a Type 1 phenotype. Diet, lifestyle advice and oral glucose‐lowering agents were commenced but persisting poor control necessitated insulin therapy in 2005. She later presented twice in diabetic ketoacidosis, suggesting conversion to a Type 1 phenotype (postprandial C‐peptide < 94 pmol/l). Despite differing insulin regimens, control remained poor with frequent hyperglycaemic and hypoglycaemic excursions, severely impairing quality of life. Whilst an inpatient in 2007 [glycated haemoglobin (HbA_1c) 10.2%, body mass index (BMI) 31.5 kg/m²] exenatide was commenced in an attempt to stabilize glycaemic control. Dramatic improvements were seen and continued. Eight months later, HbA_1c had fallen by 2% with an 8‐kg weight loss and 10‐unit reduction in daily insulin dose. Quality of life dramatically improved. C‐peptide remains undetectable. Conclusions This patient with features of both Type 1 and Type 2 diabetes benefited greatly from exenatide with insulin therapy. The improvement seen in glycaemic control could not be attributable to enhanced insulin secretion but could be as a result of a combination of the other incretin effects (postprandial glucagon suppression, delayed gastric emptying and weight loss secondary to increased satiety) all improving insulin sensitivity, reducing insulin dose and smoothing control.     

Paraoxonase polymorphisms PON1 192 and 55 and longevity in Italian centenarians and Irish nonagenarians. A pooled analysis

BACKGROUND: PON1, an arylesterase, associated with high density lipoprotein (HDL), protects low density lipoprotein (LDL) against oxidative modification. Common polymorphisms PON1 55 (L/M) and 192 (Q/R) in the PON1 gene associate with atherosclerosis and heart disease. Because long-lived people seem protected from premature vascular death, we conducted a pooled statistical analysis to assess any association between these polymorphisms and longevity in a large combined group of Italian centenarians and octo/nonagenarians from Northern Ireland (NI). MATERIALS AND METHODS: Separated DNA was available from 1479 subjects from Italy and Northern Ireland (NI). In Italy 308 centenarians (males 67, females 241, mean age 100.8, SD2.1 years) and 579 young controls (males 347, females 232, mean age 40.7, SD 12.7 years) were included in the study. In NI, 296 octo/nonagenarians (males 92, females 204, mean age 89.8, SD 5.7 years) and 296 young sex-matched subjects (mean age 13.0, SD 1.4 years) had available DNA. PON1 55 (L/M) and 192 (Q/R) polymorphisms were studied using a PCR-RFLP approach. RESULTS: There was a significant difference in PON1 192 genotypes in Italian centenarians compared to younger controls (X(2)= 6.8, df = 2 p= 0.03) and a similar but non significant trend between octo/nonagenarian and young subjects in NI (X(2) = 4.0, df=2, p=0.14). Using logistic regression analysis on the combined Italian and Irish datasets, there was a small survival advantage for centenarian and octo/nonagenarian subjects who were heterozygous for PON1 192 R allele, (OR 1.3, CI 1-1.6; p=0.04 with a stepwise increase for RR homozygous subjects (OR 1.7, CI 1.1-2.6; p = 0.02) compared to QQ subjects. Comparing R and Q alleles there was a survival advantage for octo/nonagenarian/centenarian subjects who carried the R allele (OR 1.3, CI 1.1-1.5; p = 0.007) but there was no sex-specific effect p =0.77) LL, LM and MM genotypes of PON 55 polymorphisms showed similar frequencies in Italy (39.9, 47.0, 13.1%) and Ireland (39.5, 48.6, 11.9%) with no age or sex-related differences. The PON1 192R/Q and PON55L/M loci were in strong linkage disequilibrium with a Lewontin's D' coefficient -0.928 (elderly) and -0.965 (young). There was a significant difference in haplotype frequency of these linked loci in older compared to younger subjects (Likelihood Ratio X(2) = 9.60, df = 3, p= 0.02). CONCLUSION: These data suggest a modest association between the 192R allele and longevity in two very elderly populations in two European countries. Being homozygous for 192 RR further enhances survival advantage but this effect was not found to be sex specific. This finding is of interest because the 192R allele has previously been associated with increased risk of coronary heart disease. On the other hand, the 192R allele shows higher enzymatic activity, using paraoxon as substrate, and we postulate that its role in the metabolism of potentially toxic chemicals or other metabolic pathways may be important in survival to very old age.     

Aging reduces neural specialization in ventral visual cortex

The present study investigated whether neural structures become less functionally differentiated and specialized with age. We studied ventral visual cortex, an area of the brain that responds selectively to visual categories (faces, places, and words) in young adults, and that shows little atrophy with age. Functional MRI was used to estimate neural activity in this cortical area, while young and old adults viewed faces, houses, pseudowords, and chairs. The results demonstrated significantly less neural specialization for these stimulus categories in older adults across a range of analyses.     

Detection of ischemic wall dysfunction: Comparison between M-mode echocardiography and sonomicrometry

The quantification of regional ventricular function by M-mode echocardiography was compared to that by sonomicrometry in 10 closed-chest, sedated swine during temporary occlusions of the left circumflex coronary artery. Wall thickening during systole (%WT) was calculated to quantitate regional myocardial function, and percentage of fractional shortening (%FS) was calculated from both sonomicrometer tracings and M-mode echocardiograms. Ventricular dimensions at end diastole and end systole were also compared before and after 2 minutes of coronary artery occlusion. Both techniques detected significant changes in wall thickness, %WT, and %FS after occlusion. Changes in %WT during coronary artery occlusion detected by M-mode echocardiography and sonomicrometry had a significant linear relationship (p < 0.05). Discrepancy between the two techniques in the measurement of wall thickness at end diastole was attributed to the difficulty in measuring relatively small distances with M-mode echocardiograms. However, we conclude that the clinical M-mode echocardiogram is capable of detecting acute regional wall dysfunction associated with ischemia.