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Biomedical subjects

P Armstrong

Publications and source records attributed to P Armstrong.

At least 55 records · Page 3Linked to original sources
PubMed1996

The MR appearance of vaginal fistulas.

OBJECTIVE: The aim of this study was to determine the accuracy of MR imaging in revealing complex vaginal fistulas. SUBJECTS AND METHODS: Fifteen patients with clinical symptoms of vaginal fistulas were examined with MR imaging, using a combination of T1-weighted, T2-weighted, and fast multiplanar inversion recovery sequences in the axial plane, along with T2-weighted and fast multiplanar inversion recovery sequences in the sagittal plane. Observers examined the scans for a fistula and any associated masses or collections. The MR findings were recorded with the observers unaware of the results of cystoscopy and sigmoidoscopy under anesthesia. The MR findings were correlated with examination under anesthesia. RESULTS: Vaginal fistulas were seen in ten patients. All fistulas were confirmed surgically. Of the five patients with no fistulas revealed on MR imaging, examination under anesthesia also revealed no fistulas in four. However, in the fifth patient, examination under anesthesia revealed an epithelialized track, which was not seen on MR imaging. CONCLUSION: MR imaging was accurate in revealing and delineating the extent of vaginal fistulas in patients with clinical symptoms of such fistulas.

Adult↗
PubMed1996

Unstable angina--report from a Canadian expert roundtable.

Unstable angina is generally considered to encompass a spectrum of symptomatic manifestations of ischemic heart disease, intermediate between stable angina and acute myocardial infarction. Approximately 75,000 Canadians are hospitalized yearly with unstable angina. The pathophysiology of unstable angina is still imperfectly understood, but is related to the same pathophysiological factors underlying myocardial infarction and sudden cardiac death. In March 1995 a group of Canadian cardiologists met to review the current understanding of unstable angina and to define a Canadian approach to this common problem. Important issues and questions regarding the diagnosis and management of unstable angina were defined. The objective was to outline approaches to the management of unstable angina that would be appropriate in Canada. Topics discussed included definition, incidence, clinical presentations, pathophysiology, initial diagnostic and risk stratification approaches, acute medical management, role of invasive interventions and long term management.

Angina, Unstable↗
PubMed1995

The typing of fetal antigen 2 in human amniotic fluid.

Fetal antigen 2 (FA-2) has been identified in amniotic fluid and shown to be of fetal origin. In this study we have extended previous observations on FA-2 heterogeneity with respect to both size and charge using gel filtration, ion-exchange chromatography, non-dissociating polyacrylamide gel electrophoresis and sodium dodecyl sulphate polyacrylamide gel electrophoresis. From the diversity of forms we have been able to define two principal FA-2 types, type A and type B. Type A has a high molecular mass (140 kDa), has subunits of 33 kDa and 29 kDa, and elutes at approximately 0.27 mol/l sodium chloride from diethylaminoethyl (DEAE)-Sephacel. Type B has the same mass and subunits as type A, but elutes at approximately 0.24 mol/l sodium chloride from DEAE-Sephacel. Other low molecular mass forms of FA-2 have also been identified. All FA-2 forms described were shown to be common to all amniotic fluid samples studied and were not attributable to artefacts of collection or storage. It was also demonstrated that the recently described FA-2 RIA is specific for FA-2 types A and B and the conversion of arbitrary units FA-2 into micrograms applies to type A. The typing is discussed with respect to (i) the aminopropeptide of the alpha 1 chain of human procollagen type I, (ii) the 24 kDa phosphoprotein in developing bone and (iii) fetal calf ligament protein 1 (FCL-1), suggesting that they are the same protein.

Amniotic Fluid↗
PubMed1995

Sensitive and specific colorimetric dot assay to detect eastern equine encephalomyelitis viral RNA in mosquitoes (Diptera: Culicidae) after polymerase chain reaction amplification.

A sensitive and specific colorimetric dot assay following polymerase chain reaction (PCR) method has been developed to detect 0.1 pg of eastern equine encephalomyelitis viral (EEEV) RNA. The assay is 250-fold more sensitive than analysis by electrophoresis and is based on converting a 291-nucleotide sequence of the viral coat protein amino terminus into a double-stranded DNA (dsDNA) and amplifying the DNA using a specific primer pair and PCR. The amplified complementary DNA (cDNA) is denatured adsorbed onto a nylon strip, baked, and detected with a digoxigenin-labeled probe. Dots with viral cDNA are stained dark red, whereas controls do not stain or stain lightly. The assay is very specific and sensitive and detects only EEEV. RNA of Venezuelan equine encephalitis, St. Louis encephalitis, Keystone, Flanders, Tensaw, and western equine encephalitis viruses were not detected. EEEV (Ten Broeck) RNA was detected at the 10-ng level, indicating that the prototype we used may have different nucleotides in the region where the primer pair binds. The PCR amplified EEEV cDNA that was 92% homologous to the consensus sequence of EEEV. The detection of EEEV in the liver of an infected Emu bird and in field-collected mosquitoes from Florida and Massachusetts that were analyzed concurrently as blind samples by tissue culture plaque assay and by PCR dot analysis proved that the assay is sensitive and can be used to detect infected mosquitoes. The assay can detect at least 1 infected mosquito in a pool of 1,000 uninfected mosquitoes.

Animals↗
PubMed1995

Abnormal amniotic fetal antigen 2 concentrations in trisomy 18 and trisomy 21.

Fetal antigen 2 (FA-2) is a human protein, first identified in amniotic fluid, and shown to be identical to the aminopropeptide of the alpha 1 chain of collagen type I. It exists in several different size and charge forms. In the present study, FA-2 was measured in amniotic fluid using two different assays: a rocket line immunoelectrophoretic assay which measured total FA-2, and a radioimmunoassay which was specific for the high molecular mass forms of FA-2. Both assays gave similar results. FA-2 concentrations were measured in amniotic fluid samples collected from normal pregnancies at 10-23 weeks gestation; they were shown to rise steeply from 10-14 weeks, peak at 17 weeks and then fall slightly by 23 weeks. Comparison between amniotic fluid from normal pregnancies and pregnancies affected by trisomy, showed significantly higher FA-2 concentrations in trisomy 21 and significantly lower concentrations in trisomy 18.

Amniotic Fluid↗
PubMed1994

Importance of ST-segment depression as a determinant of ventricular premature complex frequency after thrombolysis for acute myocardial infarction. Tissue Plasminogen Activator: Toronto (TPAT) Study Group.

Ventricular premature complexes (VPCs) after acute myocardial infarction (AMI) remain important determinants of survival in the post-thrombolytic era. The role of thrombolysis, left ventricular function, and Holter ST-segment depression in modulating VPC frequency is unclear. In a placebo-controlled, randomized study of tissue-type plasminogen activator (t-PA) in 103 patients with AMI (Tissue Plasminogen Activator: Toronto study), VPC frequency and ST depression on Holter monitoring (day 7), ejection fraction by radionuclide scan (day 9), and infarct artery patency and cross-sectional area on day 1 (n = 42) were assessed. After administering t-PA, VPC frequency was 10 +/- 58/hour (mean +/- SD), similar to that after placebo (23.5 +/- 91.7, p = NS). However, patients with ST depression had greater VPC frequency (56 +/- 140/hour) than those without it (1.3 +/- 2.6/hour, p = 0.05). Ejection fraction was negatively correlated with VPC frequency (r = -0.33, p < 0.001). By multivariate analysis, ejection fraction (F = 7.0, p < 0.01) and ST depression (F = 5.8, p < 0.02) were the only independent predictors of VPC frequency. In this placebo-controlled study, VPC frequency after AMI was not related to thrombolytic administration but was associated with ST depression and ejection fraction. This suggests that the underlying extent of both infarcted and ischemic myocardium is important in modulating ventricular arrhythmias after AMI.

Aged↗
PubMed1994

Magnetic resonance imaging of fistula-in-ano.

PURPOSE: Successful management of anal fistulas depends upon accurate assessment of the primary tract and any secondary extensions. Preoperative imaging has, to date, been disappointing. METHODS: A prospective study of 35 patients with a clinical diagnosis of fistula-in-ano was performed comparing magnetic resonance imaging with the independently documented operative findings. Magnetic resonance imaging was also compared with anal endosonography in 20 patients. RESULTS: Magnetic resonance imaging is accurate and demonstrates pathology missed at surgery by experienced coloproctologists. Magnetic resonance imaging is superior to anal endosonography. CONCLUSIONS: Magnetic resonance imaging is advocated as the method of choice when imaging is required for anal fistulas.

Adult↗
PubMed1994

The size of normal adrenal glands on computed tomography.

The aim of our study was to determine the size of normal adrenal glands. Measurements of the adrenal glands were obtained from computed tomographic (CT) images in 55 patients already undergoing CT for routine clinical indications. Patients with conditions known to affect the size of adrenal glands or cases with focal adrenal enlargement suggesting a mass were excluded. The following dimensions were measured: the maximum width perpendicular to the long axis of the body of the gland, and maximum width of the medial and lateral limbs. The average measurements for the right adrenal gland were: maximum width 0.61 cm (S.D. 0.2), width of the medial limb 0.28 cm (S.D. 0.08), and width of the lateral limb 0.28 cm (S.D. 0.06). The average measurements for the left adrenal gland were: maximum width 0.79 cm (S.D. 0.21), width of the medial limb 0.33 cm (S.D. 0.09), and width of the lateral limb 0.30 cm (S.D. 0.10) [corrected].

Adrenal Glands↗
PubMed1994

Computed tomography of diffuse, non-metastatic enlargement of the adrenal glands in patients with malignant disease.

The aim of this study was to test the hypothesis that diffuse non-metastatic enlargement of the adrenal glands occurs in patients with malignant disease. Measurements of the adrenal glands were obtained from computed tomographic (CT) images in two groups of patients with malignant disease (47 patients with lymphoma and 144 patients with other primary tumours) and a control group consisting of 55 patients without malignant disease. Patients with conditions known to affect the adrenal glands were excluded. Adrenal glands with focal mass lesions, as judged by CT, were also excluded. The following measurements were obtained: the maximum width perpendicular to the long axis of the gland; and maximum width of the medial and lateral limbs. There was a statistically significant difference in all measurements between the control group and the groups with lymphoma and other tumours. No significant difference was demonstrated in the size of the adrenal glands in patients with different stages of malignancy. We have shown that the adrenal glands are enlarged in patients with malignant tumours, including lymphoma. We believe that this enlargement is due to adrenal hyperplasia rather than to metastatic neoplasm.

Adrenal Glands↗
PubMed1994

The radiology of non-Hodgkin's lymphoma in childhood: a review of 80 cases.

The clinical spectrum of childhood non-Hodgkin's lymphoma (NHL) is different from that in adults, with frequent extranodal involvement. CT scanning as part of routine staging appears to show more frequent sites of extranodal disease than were previously recognized. We have reviewed the CT and other radiological findings in 80 children with NHL to document the incidence and radiological appearance of visceral involvement, to compare this with the pattern of adult disease, and to assess how frequently clinical stage of disease was altered by radiological findings. The age of the children ranged from 9 months to 17 years 4 months (mean 9 years 2 months). The presenting site was in the abdomen in 21 (27%), extranodal sites in the head and neck in 18 (23%), mediastinum in 16 (20%), peripheral lymph nodes in 15 (19%), pelvic organs in four, skin in four, and bone in two. Fifteen children had gastrointestinal lymphoma, the majority involving the ileocaecal junction. The kidneys were involved in 10 children, the pancreas in three; no child with renal or pancreatic involvement had associated retroperitoneal lymph node enlargement. Eight children had bone involvement and only two of the 80 children had pulmonary nodules at presentation. In this series, of the 44 children who had CT of the chest and abdomen, only five had stage of disease increased as a result, three with the primary disease in peripheral lymph nodes, and two with the primary disease in extranodal sites in the head and neck.

Abdominal Neoplasms↗
PubMed1994

Magnetic resonance imaging of fistula-in-ano: technique, interpretation and accuracy.

The aim of this study was to document the appearances of fistula-in-ano on magnetic resonance imaging (MRI) and to prospectively evaluate the accuracy of MRI in the pre-operative assessment of anal fistulae. Patients with a clinical diagnosis of fistula-in-ano and awaiting surgery (n = 35) were examined with MRI. The fistulous tracks with their secondary extensions and abscesses are readily seen as low signal on T1-weighted images and high signal areas on STIR images. In order to determine the accuracy of the MRI interpretations, an experienced coloproctologist operated on all 35 patients without the knowledge of the scan interpretations and the findings at surgery were compared with the MRI scan interpretations. Concordance rates between MRI and operative findings were 86% for presence and course of the primary track, 91% for the presence and site of secondary extensions or abscesses and 97% for the presence of horse-shoeing. Although operative findings by an experienced coloproctologist were taken as the gold standard, we have shown that in 9% of our study group, failure of healing was related to pathology missed at surgery which had been documented on pre-operative MRI. It is probable, therefore, that the accuracy of MRI is higher than the figures quoted above. MRI is advocated as the imaging method of choice in the assessment of anal fistulae and its use may lead to a reduction in the recurrence rate due to inaccurate surgical assessment.

Adult↗
PubMed1994

General practitioners' views of clinical guidelines for the management of asthma.

OBJECTIVES: To assess the views of GPs on the value of clinical guidelines for the management of asthma. DESIGN: Structured questionnaire survey. SETTING: Bromley Health District. SUBJECTS: All (160) GPs in health district. MAIN OUTCOME MEASURES: Evaluation of each item of clinical guidelines as to whether 'obvious', 'useful' or 'controversial'. RESULTS: Ninety-four (59%) of GPs responded. There was considerable variation in views on all 26 guideline items in the questionnaire. The average GP thought that 11.5 items were obvious, 8.5 useful and 5.7 controversial, but these views showed no relationship to the GP's age, sex, ethnicity or partnership size. CONCLUSION: Clinical guidelines are usually written to be of value to a wide number of clinicians, but it appears that GPs at least have more individual needs on issues of clinical management. This may explain the reported limited impact of guidelines on clinical practice.

Analysis of Variance↗
PubMed1994

The adrenal gland.

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Adrenal Gland Diseases↗