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Biomedical subjects

C McAllister

Publications and source records attributed to C McAllister.

At least 19 recordsLinked to original sources
PubMed2004

Agreement between ambulance paramedic- and physician-recorded neurological signs with Face Arm Speech Test (FAST) in acute stroke patients.

BACKGROUND AND PURPOSE: Patients with suspected stroke first assessed by ambulance paramedics require early recognition to facilitate appropriate triage and early treatment. We determined paramedic's accuracy in detecting acute stroke signs by comparing agreement between neurological signs recorded in the Face Arm Speech Test (FAST), a stroke recognition instrument, by paramedics on the scene and by stroke physicians after admission. METHODS: Suspected stroke patients admitted by ambulance paramedics directly to an acute stroke unit through a rapid ambulance protocol were examined by a trainee stroke neurologist or admitting stroke physician over a 1-year period. Recorded neurological signs (facial weakness, arm weakness, speech disturbance) in confirmed acute stroke/transient ischemic attack (TIA) cases were compared between paramedics and the stroke neurologist/physician. RESULTS: Ambulance crews referred 278 suspected stroke patients of whom 217 (78%) had confirmed stroke (n=189) or TIA (n=28); 95% were examined by the stroke neurologist (median 18 hours after paramedic assessment). Recorded signs and agreement between paramedics and stroke physicians in confirmed stroke group were: facial weakness, 68% versus 70% (kappa=0.49; 95% CI: 0.36 to 0.62); arm weakness, 96% versus 95% (kappa=0.77; 95% CI: 0.55 to 0.99); and speech disturbance, 79% versus 77% (kappa=0.69; 95% CI: 0.56 to 0.82). Interrater agreement was complete for arm weakness in 98% cases. CONCLUSIONS: Recognition of neurological deficits by ambulance paramedics using FAST shows good agreement with physician assessment, even allowing for temporal evolution of deficits. The high prevalence and good agreement for arm weakness suggest that this sign may have the greatest usefulness for prehospital ambulance triage and paramedic-based neuroprotective trials.

Acute Disease↗
PubMed2002

Smoking behaviour and knowledge in high school students in Riyadh and Belfast.

UNLABELLED: Smoking is one of the risk factor associated with onset, severity and progression of periodontal disease. AIM: The aim of the study was to examine the smoking behaviour and dental health knowledge of high school students in Riyadh and Belfast. MATERIALS AND METHODS: Eight schools from Riyadh and 6 from Belfast were randomly selected by cluster distribution sampling method. Two hundred and ninety students from Riyadh and 144 from Belfast were included giving an overall response rate of 85%. The age range was between 16-17 years. A questionnaire was used to assess demography, smoking habits, dental health knowledge and oral hygiene practices. RESULTS: The results showed that 18% of students were smokers; 24% in Belfast and 15% in Riyadh (x2 (1) = 4.29: P = 0.04). 24% of students in Belfast and 56% in Riyadh smoked at least 1 cigarette per day. 61% of students had bleeding gums although 85% stated that they brushed their teeth at least daily. Bleeding on brushing was common with 53% of Belfast students compared with 65% from Riyadh. Students in Belfast (2.51 +/- 1.15) had significantly higher mean scores for their knowledge about gum health compared with Riyadh students (2.21 +/- 1.44) (t = 2.29: P = 0.02). There was no differences in knowledge about oral health and smoking between the students. However, non-smokers from Belfast and Riyadh (3.32 +/- 1.60) had greater knowledge about oral health and smoking than those who smoked (2.81 +/- 1.45) (t = 2.73: P = 0.007). There was no difference in knowledge about gum health between smokers and non-smokers. CONCLUSIONS/RECOMMENDATIONS: Smoking is more prevalent in Belfast but more cigarettes are smoked in Riyadh. As non-smokers had greater knowledge of the ill-effects of smoking upon their oral health, there is a need to develop location specific interventions to control smoking habits in late adolescence.

Adolescent↗
PubMed1997

Effect of enalapril therapy on glomerular accumulation of immune complexes and mesangial matrix in experimental glomerulonephritis in the nonhuman primate.

The present study is a prospective, controlled, blinded trial of enalapril therapy in experimental immune complex (IC)-mediated glomerulonephritis (GN) in the nonhuman primate (cynomolgus monkey [CYN]). Two groups of CYNs were studied: those with established GN (study A) and those in which GN was being induced (study B). In study A, 12 CYNs had GN established by 8 or 10 weeks of daily intravenous infusion of bovine gamma-globulin (BGG). These CYNs were then assigned to either 4 weeks of daily oral enalapril therapy (n = 6) or daily oral placebo therapy (n = 6). The daily BGG infusions were continued during the 4 weeks of enalapril or placebo therapy. At the start of the enalapril/placebo protocol, the two groups were similar with respect to proteinuria and level of precipitating antibody to BGG, which determined the daily BGG dose. Renal biopsy was performed in each CYN at the start and end of the 4-week period of enalapril/placebo protocol. In study B, 15 normal CYNs were immunized to BGG over a period of 4 weeks. The CYNs were then assigned to daily oral enalapril therapy (n = 8) or placebo therapy (n = 7) based on level of precipitating antibody to BGG. At this point, daily intravenous BGG was begun along with daily enalapril or placebo for 8 weeks. Renal biopsy was performed in each CYN before and at the end of this 8-week period. In study A, enalapril therapy was associated with a significant decrease in mesangial matrix volume (mean change, -27.7%; P = 0.031) and a trend toward decreased mesangial matrix deposits (mean change, -34.1%; P = 0.188). By contrast, in CYNs receiving placebo therapy, mesangial matrix volume increased compared with the enalapril group (P = 0.002) and mesangial deposits were unchanged. In study B, both the enalapril and placebo groups showed significant increases in mesangial matrix volume, mesangial deposits, mesangial cell volume, and capillary wall deposits during the 8 weeks of daily BGG infusion. However, none of the differences between the groups achieved statistical significance. Changes in mesangial cell volume and capillary wall deposits were also evaluated in study A and study B, but were not found to be different between the enalapril and placebo groups. In both study A and study B, blood pressure was lower in the enalapril groups. In conclusion, in the initial phase of IC-GN induction (0 to 8 weeks), enalapril therapy does not significantly influence the glomerular accumulation of mesangial matrix or immune deposits. However, in established IC-GN (after 8 weeks of GN induction), enalapril therapy significantly decreases the further accumulation of mesangial matrix and may decrease the further accumulation of mesangial deposits. Whether this benefit of enalapril therapy was related to lower blood pressure or to other effects of angiotensin-converting enzyme (ACE) inhibition was not determined in this study.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1994

Effect of chronically increased erythrocyte complement receptors on immune complex nephritis.

Experimental studies in humans and other primates have shown that the erythrocyte (E) complement receptor Type 1 (CR1), which is unique to the primate, plays an important role in clearing immune complexes (IC) from the circulation by binding C3b/C4b opsonized immune complexes and carrying the IC to liver and spleen for disposal. The results of these acute experiments suggest that increasing E-CR1 levels chronically should protect against IC-mediated glomerulonephritis (IC-GN) induced by chronic formation of IC in the circulation. In the present study this hypothesis was tested in the cynomolgus monkey (CYN). IC-GN was induced by daily bolus intravenous infusion of BGG into immunized CYN for 8, 10, or 14 weeks. Prior to and during the daily bolus infusions of BGG, sustained differences in E-CR1 levels were achieved between the experimental group (increased E-CR1 levels) and the control group (maintained or decreased E-CR1 levels), by one of two methods: (1) Twice weekly exchange transfusion. The CYN donors were blood type compatible with the recipients and had either constitutive high E-CR1 expression (3,000 to 5,000 CR1/E) or constitutive low E-CR1 expression (< 100 CR/E). The recipients of the exchange transfusions (N = 2) had constitutive mid-level E-CR1 expression. (2) Weekly phlebotomy (PL) or sham PL. CYN with mid-level E-CR1 expression were randomly assigned to receive weekly either PL (causing increased E-CR1 expression by stimulating erythropoiesis) (N = 8) or sham PL (which has no effect on E-CR1 expression (N = 9).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

2'-substituted chalcone derivatives as inhibitors of interleukin-1 biosynthesis.

A series of 2'-substituted chalcone derivatives has been found to show potent inhibition of the production of IL-1 beta from human peripheral blood monocytes stimulated with lipopolysaccharide (LPS), with IC50 values in the 0.2-5.0-microM range. Some members of the series have also shown inhibition of septic shock induced in mice by injection of LPS, although with low potency. Qualitative structure-activity relationships have shown that the enone is required for activity, which may be mediated by conjugate addition of a biological nucleophile to the chalcone. Electron-poor aromatic rings beta to the ketone give enhanced potency. Although electronic effects in the other ring (directly attached to the ketone) are minimal, this ring must possess an ortho substituent for good activity without cytotoxicity, suggesting a degree of selectivity which would not be expected for simple, nonspecific alkylating agents.

Animals↗
PubMed1993

Platelet involvement in experimental immune complex-mediated glomerulonephritis in the nonhuman primate.

Abundant glomerular platelet deposition is a hallmark of certain animal models of immune complex (IC)-mediated glomerulonephritis (GN). By contrast, conspicuous platelet deposition is uncommon in the IC-GN seen in humans. This could result from intrinsic differences between human and animal platelets, which are known to be present. To assess whether abundant glomerular platelet deposition can occur in humans with IC-GN, the present studies were undertaken in nonhuman primates (cynomolgus monkeys, CYN), with active experimental IC-GN induced by 12 weeks of daily intravenous infusion of bovine gamma globulin (BGG). CYN are appropriate for these studies because, like humans, CYN platelets do not express the C3b receptor but do express receptors for the Fc region of IgG (FcR gamma II). Furthermore, in this model of IC-GN, which is indistinguishable from IC-GN seen in humans, it is possible to time the biopsy to coincide with a period of peak activity of the GN. The present studies proceeded as follows: ten CYN were studied before and after intravenous infusion of BGG sufficient to achieve conditions near antigen/antibody equivalence for circulating precipitating antibody to BGG. The infusion of BGG, which was given over 10 minutes, resulted in an acute reduction in circulating platelets (mean 43% +/- 5 SE, P < 0.001). However, renal biopsies performed before and five minutes after the acute reduction in circulating platelets showed that relatively few of the platelets removed from the circulation lodged in glomeruli (platelets/glomerular cross section: 0.2 +/- 0.06 before BGG vs. 0.88 +/- 0.31 after BGG, P = 0.035). In five of the CYN studied under the above protocol, autologous platelets were labeled with 111In and reinfused into the CYN just prior to the BGG infusion. These studies confirmed the paucity of platelet deposition in kidney but showed major uptake of the 111In-labeled platelets by liver and spleen (mean +/- SE 111In CPM/mg of tissue: kidney cortex 18 +/- 8, liver 132 +/- 42, and spleen 808 +/- 127, P = 0.038, comparing kidney to liver or spleen by paired t-test). Thus, the platelets removed from the circulation were taken up at the sites which are also the principal sites of IC uptake (liver and spleen), and over the time interval that coincides with the period of maximum uptake of IC by liver and spleen, after BGG infusion. In vitro studies, discussed herein, showed that BGG anti-BGG IC bind to CYN platelets via FcR gamma II.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

A comparison of five devices for the bedside monitoring of heparin therapy.

Five instruments were tested for their capacity to monitor heparin therapy on whole blood at the bedside. The instruments were 512 Coagulation Monitor (Ciba-Corning), Thrombotrack (Nycomed), Automated Coagulation Timer (Hemotec), Hemochron-ACT and Hemochron-APTT (International Technidyne Corporation). Fifty subjects with various levels of heparinisation were tested on each instrument and were also assayed for antithrombin III, fibrinogen, haematocrit, platelet count and plasma heparin level. The results were compared with a reference APTT performed on the Automated Coagulation Laboratory 300R (Instrumentation Laboratories). The Hemochron-ACT correlated least well. The Hemotec and Thrombotrack were unsuitable in a clinical setting because of pipetting requirements, although the Thrombotrack did correlate well with the reference parameters. The 512 Coagulation Monitor was the simplest to use, but its maximum response corresponded to the midpoint of the reference APTT therapeutic range. The Hemochron-APTT was simple to use, had an adequate response range and correlated well with reference parameters.

Blood Coagulation Tests↗
PubMed1990

Altered skin temperature and electromyographic activity in the irritable bowel syndrome.

A prospective study to determine the presence or absence of any difference in skin temperature and electromyographic (EMG) activity in 20 patients with irritable bowel syndrome (IBS) compared with 20 age- and sex-matched controls was conducted. A representative digital temperature and EMG activity during 4 phases, baseline, mental activity (arithmetic), unpleasant thoughts and audio biofeedback relaxation, were recorded using standard biofeedback equipment. Results showed the IBS group to have a significantly lower digital temperature and significantly higher EMG activity during the baseline and arithmetic phases. No difference was found in EMG activity for the unpleasant thought or audio biofeedback relaxation phases. Indeed, the IBS group were able to achieve a level of EMG activity during the audio feedback relaxation phase that approximated very closely that of the control group. These results provide further evidence suggestive of altered autonomic nervous system function in IBS patients and indicate that further studies should be undertaken to determine whether the reduction achieved in EMG activity post-relaxation is sustained, and if so, if it is associated with a corresponding improvement in symptoms.

Adolescent↗
PubMed1988

Patients with pulse rate changes in irritable bowel syndrome. Further evidence of altered autonomic function.

Patients with the irritable bowel syndrome have significantly more rapid and significantly greater slowing of the pulse rate than do age-, sex-, and stressor-matched controls when their pulse rate is measured at initial outpatient clinic attendance. These findings provide further evidence that altered autonomic function exists in patients with the irritable bowel syndrome.

Adolescent↗
PubMed1987

Retinal vascular endothelium expresses fibronectin and class II histocompatibility complex antigens in experimental autoimmune uveitis.

To analyze the role of the retinal vascular endothelial cells in the development of experimental autoimmune uveitis (EAU), we studied the presence of Ia antigen and FN in retinal vessels of Lewis rats immunized with retinal S antigen. Immunopathologic studies were performed on frozen tissues obtained during various stages of the disease. Our results show that Ia antigen was not present in the normal rat retina, and there was very little FN present in a few retinal vessels. One to two days prior to the histologic and clinical onset of EAU, FN was found to be increased in the retinal vessels. Ia antigen was found to be present in the retinal vessels coincident with the first signs of cellular infiltration. During the stage of maximal cellular infiltration, FN was present diffusely throughout the retina, as well as in the subretinal space, and Ia antigen was found diffusely in the cellular infiltrate. Therefore, FN and Ia antigen reflect the immunomodulation of vascular endothelial cells in EAU, which may be very important in the pathogenesis of retinal S antigen-induced uveitis. Two possible mechanisms for the role of the activation of the retinal vascular endothelium in the development of retinal inflammation in uveitis are discussed.

Animals↗
PubMed1986

Is hypertrophic osteoarthropathy really so rare in regional enteritis?

We describe a patient with hypertrophic osteoarthropathy secondary to regional enteritis, and review the literature on their association. The apparent different distribution of hypertrophic osteoarthropathy secondary to other causes may be artifactual and related to inadequate radiological investigation. Hypertrophic osteoarthropathy does not appear to be related to regional enteritis activity.

Crohn Disease↗
PubMed1985

T-lymphocyte subsets in experimental autoimmune uveitis.

The dynamic changes of the lymphocyte subsets in the inflamed ocular tissue in Lewis rats with experimental autoimmune uveitis (EAU) were studied by immunohistopathological evaluation at varying intervals after initiation of the disease. Monoclonal antibodies to specific markers of the rat T-helper/inducer lymphocyte (W3/25) and T-suppressor/cytotoxic lymphocyte (OX-8) were used in the avidin-biotin-peroxidase complex (ABC) method. During the early stages of the disease following the acute inflammatory reaction, the T-helper/inducer lymphocytes are found in larger numbers within the infiltrates, the relative number of the T-suppressor/cytotoxic cells is very low during the initial phases, with a ratio as low as 5 to 1. During the later stages, there is a continuous increase in the relative number of suppressor/cytotoxic cells that reaches the ratio of 1 to 1, or even 1 to 2. It is postulated that the observed changes in the ratios between T-helper/inducer and T-suppressor/cytotoxic cells during the different stages of EAU may reflect the kinetics and regulation of the inflammatory response in autoimmune diseases.

Animals↗