Degree of cervical carotid artery stenosis and hemispheric stroke: duplex US findings

Duplex ultrasound (US) scans of 110 carotid arteries ipsilateral to hemispheric strokes were compared with scans of 90 asymptomatic vessels in the same patients to determine the relative prevalence of stenotic lesions. In addition, scans of paired carotid arteries in patients with stroke involving only one cerebral hemisphere were compared to determine whether the incriminated side demonstrated a greater degree of stenosis than the asymptomatic side. The duplex US findings demonstrated a positive correlation between stenosis and hemispheric stroke. However, only 20% of carotid arteries ipsilateral to hemispheric stroke showed a reduction in diameter greater than 70%, compared with 5% of asymptomatic vessels. A minimal difference was demonstrated between the symptomatic and asymptomatic groups with respect to lesser degrees of stenosis. In paired carotid arteries, the degree of stenosis of the symptomatic vessel exceeded that of the asymptomatic vessel in only 43% of cases. These results suggest that the prevalence of severe carotid stenosis in stroke patients has been previously overestimated. The findings also emphasize the need for further investigation of other plaque-related risk factors that may enhance stroke prevention through improved selection of surgical or medical therapy. Factors currently under investigation include plaque ulceration, intraplaque hemorrhage, plaque echogenicity, and the effects of sequential stenoses.     

Variation in the isocentre of a Philips Linear Accelerator (SL–20) used for stereotactic radiosurgery/stereotactic radiotherapy

Stereotactic irradiation, either in the form of stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT) of brain lesions requires high precision and submillimetre accuracy in the isocentre, the main determinants being gantry and couch rotations. It is thus necessary to evaluate the isocentre variation due to gantry and couch rotations in the particular setup for SRS/SRT. This paper describes variation in the isocentre of a Philips (now Elekta) SL-20 linear accelerator modified for adapting a couch-mounted radiosurgery system. By considering the isocentre as defined by a mechanical index as the standard, the variations in the isocentre of the linear accelerator were independently measured for the gantry and for couch rotations. The variation in the isocentre for gantry rotation was found to be between 0.1 mm and 0.9 mm, conforming to the submillimetre accuracy required for SRS/SRT. However, the isocentre variation due to couch rotation varied considerably, possibly because the couch is of the RAM type. The isocentre variation due to couch rotation is rectified by microadjusting the couch mount at the time of treatment using a laser target localizing frame. It is our conclusion that a modified linear accelerator can be used for performing SRS/SRT after careful and separate evaluation of the isocentre stability due to gantry and couch rotations.     

A study of immunological profile,disease characteristics and socioeconomic status of a population of rheumatoid arthritis patients in Sri Lanka

ObjectiveTo study the immunological profile, disease characteristics and socioeconomic status of a population of patients with rheumatoid arthritis (RA) in Sri Lanka.MethodsA case-control study was undertaken to characterize the immunoglobulin profiles of 105 RA and, age and gender matched osteoarthritis (OA) patients (n = 30) from the National Hospital, Sri Lanka. Healthy, non-arthritic individuals (n=30) served as controls. Sera were assayed for immunoglobulins [IgG, IgM, IgE and IgA isotypes] by establishing sandwich type ELISA. IgM, IgG and IgA rheumatoid factors (RFs) of 162RA patients were assayed by indirect ELISA. Disease characteristics and socioeconomic factors were accrued via an interviewer-administered questionnaire.ResultsHigher IgG, IgM, IgE, IgA and lower IgG1, IgG2 levels were observed in RA sera compared with controls (P < 0.05). Novel correlations between disease characteristics and immunoglobulins, as well as group-specific correlation matrices of immunoglobulins and RFs (P < 0.05) of seropositive and seronegative patients, were found. Higher IgM-RF and IgA-RF levels in seropositives and IgG-RF in seronegatives were evident compared with controls (P < 0.05). Immunoglobulin and RF profiles did not reflect gender disparity of RA (P > 0.05). Proportions of seropositives with nodules and erosions were significantly higher than seronegatives (P < 0.05). While IgM-RF and erosions positively correlated in the seropositives (P < 0.05), the seronegatives showed an inverse correlation between IgG-RF and erosions (P < 0.01). Familial clustering imposed a relative risk of 4.7 for developing seropositive RA.ConclusionsThis model study provides baseline information on pathogenetic aspects of RA in Sri Lanka, which may have implications for further research on management of the disease.     

Linkage analysis of candidate regions for coeliac disease genes

A strong HLA association is seen in coeliac disease [specifically to the DQ(alpha1*0501,beta1*0201 heterodimer], but this cannot entirely account for the increased risk seen in relatives of affected cases. One or more genes at HLA-unlinked loci also predispose to coeliac disease and are probably stronger determinants of disease susceptibility than HLA. A recent study has proposed a number of candidate regions on chromosomes 6p23 (distinct from HLA), 6p12, 3q27, 5q33.3, 7q31.3, 11p11, 15q26, 19p13.3, 19q13.1, 19q13.4 and 22cen for the location of a non-HLA linked susceptibility gene. We have examined these regions in 28 coeliac disease families by linkage analysis. There was excess sharing of chromosome 6p markers, but no support for a predisposition locus telomeric to HLA. No significant evidence in favour of linkage to coeliac disease was obtained for chromosomes 3q27, 5q33.3, 7q31.3, 11p11, 19p13.3, 19q13.1, 19q13.4 or 22cen. There was, however, excess sharing close to D15S642. The maximum non-parametric linkage score was 1.99 (P = 0.03). Although the evidence for linkage of coeliac disease to chromosome 15q26 is not strong, the well established association between coeliac disease and insulin dependent diabetes mellitus, together with the mapping of an IDDM susceptibility locus (IDDM3) to chromosome 15q26, provide indirect support for this as a candidate locus conferring susceptibility to coeliac disease in some families.      

Building a robust, scalable and standards-driven infrastructure for secondary use of EHR data: the SHARPn project

The Strategic Health IT Advanced Research Projects (SHARP) Program, established by the Office of the National Coordinator for Health Information Technology in 2010 supports research findings that remove barriers for increased adoption of health IT. The improvements envisioned by the SHARP Area 4 Consortium (SHARPn) will enable the use of the electronic health record (EHR) for secondary purposes, such as care process and outcomes improvement, biomedical research and epidemiologic monitoring of the nation's health. One of the primary informatics problem areas in this endeavor is the standardization of disparate health data from the nation's many health care organizations and providers. The SHARPn team is developing open source services and components to support the ubiquitous exchange, sharing and reuse or 'liquidity' of operational clinical data stored in electronic health records. One year into the design and development of the SHARPn framework, we demonstrated end to end data flow and a prototype SHARPn platform, using thousands of patient electronic records sourced from two large healthcare organizations: Mayo Clinic and Intermountain Healthcare. The platform was deployed to (1) receive source EHR data in several formats, (2) generate structured data from EHR narrative text, and (3) normalize the EHR data using common detailed clinical models and Consolidated Health Informatics standard terminologies, which were (4) accessed by a phenotyping service using normalized data specifications. The architecture of this prototype SHARPn platform is presented. The EHR data throughput demonstration showed success in normalizing native EHR data, both structured and narrative, from two independent organizations and EHR systems. Based on the demonstration, observed challenges for standardization of EHR data for interoperable secondary use are discussed.     

Steel occlusion coils: pretreatment with thrombin

Stainless steel vascular occlusion coils provide a convenient and effective means for occluding large vessels. Occasionally, coagulopathies or extremely high-flow states delay or preclude the formation of an effective thrombus around this device. A technique is described for pretreating these coils with a thrombin solution. This pretreatment assures a prompt and effective occlusion of the target vessel.