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Biomedical subjects

M J McCabe

Publications and source records attributed to M J McCabe.

32 records · Page 2Linked to original sources
PubMed1992

Acute myocardial infarction related to smoke inhalation and myocardial bridging.

A previously healthy 26 year old woman who was exposed to smoke during a house fire developed acute anterior myocardial infarction complicated by ventricular fibrillation. Subsequent left ventriculography confirmed anterior infarction, but coronary arteriography was normal apart from myocardial bridging over a segment of the left anterior descending artery. The development of acute myocardial infarction in this patient suggests that, in the presence of bridging, carbon monoxide inhalation may cause regional infarction.

Adult↗
PubMed1992

Audit of an emergency ambulance service: impact of a paramedic system.

The purpose of this survey was to assess the workload of an emergency ambulance service, to describe the use of paramedic skills by those staff with full extended training, and to predict the impact upon the provision of pre-hospital care of deploying a paramedic on every emergency ambulance. Accordingly, a week-long survey was undertaken of all urgent and emergency calls received by an ambulance service covering a mixed urban and semi-rural area of 187 square miles with a population of 396,000. Of the total 682 emergency calls 351 (51.5%) originated from the '999' system: 291 of these patients were taken to hospital where 51% were thought to have minor conditions and 141 were admitted. General practitioners made 236 (34.6%) emergency calls: 234 patients were taken to hospital where 76.4% were thought to have potentially serious conditions or an acute risk to life and 217 were admitted. There was no difference in the type or severity of conditions attended by paramedic or non-paramedic crews. Time spent on-scene was significantly longer when paramedics were present (mean 11.0 min, 95% confidence interval 9.54-12.46 min v 8.31 min, 7.49-9.13 min) (p less than 0.01). Extended skills were used by paramedics in 42 (23.6%) of their patients, most of whom were medical cases. One patient was resuscitated from cardiac arrest. The presence of a paramedic on every emergency ambulance increases the time spent on-scene and offers advanced pre-hospital skills to patients who need them. Care should be taken to ensure that the benefits of time spent on-scene using such skills outweigh the disadvantage of delayed hospital admission.

Allied Health Personnel↗
PubMed1991

Lead influences translational or posttranslational regulation of Ia expression and increases invariant chain expression in mouse B cells.

The molecular mechanisms governing the increased cell surface expression of major histocompatibility complex (MHC) class II molecules (Ia) on lead-treated mouse B cells was investigated. Lead has been shown to directly cause a selective, two-fold increase in the B cell's surface density of both products of the I region of the mouse MHC, I-A and I-E. In the present study, Western blot analysis showed that Pb increases the total cellular pool of I-A beta-chain by twofold. The increase in cellular I-A was not found to be due to increased messenger RNA (mRNA) for either the alpha- or the beta-chain of I-A. Biosynthetic labeling studies showed that Pb increases the translation or the stability of the Ia-associated invariant chain (Ii or gamma) and possibly the beta-chain of Ia. Collectively these results suggest that Pb increases the B cell's surface Ia by influencing translational or posttranslational regulation of Ia and/or Ia-associated chains.

Animals↗
PubMed1991

Lead, a major environmental pollutant, is immunomodulatory by its differential effects on CD4+ T cells subsets.

Studies were undertaken to address the necessity of B-T cell contact for the enhancement of B cell differentiation caused by the heavy metal lead (Pb). Membrane segregated cultures were used so that the influences of direct B-T cell contact and T cell factors on B cell differentiation could be independently evaluated. B-T cell contact was not absolutely required for Pb's enhancement of B cell maturation to antibody forming cells (AFCs); however, enhancement of the AFC response by Pb was optimal when B-T cell interactions were allowed. These results were corroborated by use of anti-L3T4 (mouse CD4) to block CD4+ T cell-B cell interaction. Blockade of B-T cell contact with anti-L3T4 did not inhibit the enhancement of the AFC response by Pb. Additional experimentation showed that Pb enhanced the AFC response and Ig production in the presence of antigen-specific T cell help, suggesting that Pb enhances B cell differentiation by augmenting cognate help rather than by inducing a response to Pb-altered-self. In studies employing antigen-specific T cell clones, Pb was found to differentially modulate antigen presentation to TH1 versus TH2 T cell clones, in that TH1 activation was inhibited and TH2 activation was enhanced by Pb.

Animals↗
PubMed1990

The heavy metal lead exhibits B cell-stimulatory factor activity by enhancing B cell Ia expression and differentiation.

Lead (Pb) has been shown to enhance B cell differentiation and to induce T cell proliferation in vitro. Our work demonstrates a direct enhancing effect of Pb on IgM production by T cell depleted-, LPS-activated B cells. Pb also caused a significant, dose-dependent increase in the B cell surface density of both products from the I-region of the murine MHC, I-A and I-E, that was comparable to and within the same time frame as other conventional B cell activators. Pb did not alter B cell surface density of MHC class-I molecules, but it did modulate the levels of other relevant activation Ag such as sIgD and Fc epsilon R. The modulation of the B cell phenotype caused by Pb was not due to release of IL-4 from residual T cells or endotoxin contamination of any culture reagents. Hg also increased cell surface MHC class II molecule density; however, neither Ni, Zn, nor Cd modulated Ia, indicating that immunomodulatory metals have different mechanisms of action. These results suggest that the mechanism of Pb immunopotentiation might be due to increased B-Th cell collaboration and that Pb can act as a B cell stimulatory factor. In addition to the obvious environmental implications of these results, determining Pbs mechanism of action on B cells may yield important information relevant to B cell activation in general.

Animals↗
PubMed1987

Deaths in three accident and emergency departments.

A survey of three London hospitals found that approximately 0.45 patients per thousand new attenders die in the accident and emergency department and that there is evidence of poor management in about 10% of these deaths. The commonest faults were excessive delay before starting appropriate treatment and neglect of the basic principles of emergency medicine. These points need to be emphasized in the training of accident and emergency staff.

Cause of Death↗
PubMed1986

Diagnostic neuroimaging in stroke. The complementary roles of referring physician and neuroradiologist.

The number and sophistication of neuroimaging methods for identifying location, size, type, and causes of stroke or stroke-like syndromes have expanded rapidly. In acute stroke, computed tomography is used to distinguish between nonhemorrhagic and hemorrhagic infarction and to eliminate several potential alternative diagnoses. Cerebral angiography can identify surgically treatable lesions in patients experiencing transient ischemic attacks and thus aid in preventing stroke. The superb sensitivity of magnetic resonance imaging has opened new vistas in the ongoing investigation of multiinfarct dementia and small infarcts in neurologically "noneloquent" regions of the brain. The more complete the referring physician's clinical and neurologic workup, the more able is the neuroradiologist to structure and coordinate the safest, fastest, and most cost-effective plan of neuroimaging to diagnose a patient's neurologic problem.

Cerebral Angiography↗
PubMed1984

Ice-skating and roller disco injuries in Dublin.

A comparative study was carried out on a series of 72 ice-skating and 57 roller skating injuries over a sixteen month period. The average patient age was 20.5 years in the ice-skating group and 16.5 years in the roller skating group. Females predominated in both groups accounting for 72% of ice-skaters injured and 77% of roller skaters injured. Ice-skaters sustained more serious injuries than roller skaters as was evident from the significant difference in fracture numbers in the two groups. Ice-skating fractures accounted for 40% of all injuries while roller skating fractures were only 14% of their total injuries. The majority of ice-skating fractures occurred in females. As a result of our study we recommended several preventative measures.

Adolescent↗