Challenges of Francisella classification exemplified by an atypical clinical isolate

The accumulation of sequenced Francisella strains has made it increasingly apparent that the 16S rRNA gene alone is not enough to stratify the Francisella genus into precise and clinically useful classifications. Continued whole-genome sequencing of isolates will provide a larger base of knowledge for targeted approaches with broad applicability. Additionally, examination of genomic information on a case-by-case basis will help resolve outstanding questions regarding strain stratification. We report the complete genome sequence of a clinical isolate, designated here as F. novicida-like strain TCH2015, acquired from the lymph node of a 6-year-old male. Two features were atypical for F. novicida: exhibition of functional oxidase activity and additional gene content, including proposed virulence determinants. These differences, which could potentially impact virulence and clinical diagnosis, emphasize the need for more comprehensive methods to profile Francisella isolates. This study highlights the value of whole-genome sequencing, which will lead to a more robust database of environmental and clinical genomes and inform strategies to improve detection and classification of Francisella strains.     

护士对院内卒中识别和救治流程的知晓率及教学需求调查分析

目的     调查护士对院内卒中识别和救治的知晓率和教学需求,为针对性地制订培训内容和计划提供借鉴,以提高培训质量。     

Stimulation of brainstem nuclei in the cat: Effect on neuronal activity in the primary visual cortex of relevance to cerebral blood flow and migraine

The electrical activity of single neurons was recorded in the primary visual cortex of anesthetized cats in order to test the hypothesis that changes in their activity might be the cause of the changes in blood flow seen after stimulation of the brainstem and in migraine. Discharge evoked by optic radiation stimulation was facilitated by conditioning stimulation (6 pulses over 24 msec) of the locus coeruleus (LC), whereas no consistent effect was exerted on resting discharge. No clear difference could be demonstrated between the effect on resting discharge of short-duration stimulation of the LC, midbrain reticular formation and dorsal raphe nucleus (DRN). Stimulation of these structures at 5/sec for 10 sec was also studied to ascertain whether long-term changes in neuronal activity could be produced, and to indicate whether changes in cerebral blood flow previously described with these parameters of stimulation were secondary to alterations in metabolic demand due to increased or decreased bulk neuronal activity. The vast majority of single neurons were unaltered by these parameters of stimulation, suggesting that cortical blood flow changes following LC and DRN stimulation are due to a direct action on the cortical microcirculation.     

Prevalence of antibody to Trypanosoma cruzi among blood donors in Los Angeles, California

Transfusion-associated Chagas' disease is a serious public health problem in Central and South America. With the recent influx of immigrants from Chagas' disease-endemic areas, concern about the risk of disease from blood transfusion has increased in the United States. To assess the prevalence of Trypanosoma cruzi infection in one area, 1024 consecutive blood donations from 988 voluntary blood donors at a medical center in Los Angeles County were screened serologically. The median age of donors screened was 32.5 years; 53.4 percent were male, and 38.4 percent were born in Chagas' disease-endemic countries. All donor sera were tested by complement fixation (CF) and indirect immunofluorescence (IIF) tests. A radioimmunoprecipitation assay (RIPA) was also done on all sera from CF- or IIF-reactive donors and an equal number of sera from nonreactive donors. A second serum specimen was obtained, and interviews were completed for 18 (67%) of 27 donors with an initial CF titer greater than or equal to 8 or an IIF titer greater than or equal to 64. The overall seroreactivity (by CF and IIF) was 1.1 percent (11/988). One donor (0.1%) had antibody specific to the 72- and 90-kDa antigens of T. cruzi on RIPA. Seven recipients of blood components from the seroreactive donors were located and were seronegative at 3 to 6 months. Seroreactive donors were 3.6 times more likely to have been born or to have resided in Mexico or Central America, 8.7 times more likely to have donated blood in the past, and 11.8 times more likely to have a history of malaria prophylaxis or treatment.