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Biomedical subjects

N Cassidy

Publications and source records attributed to N Cassidy.

At least 19 recordsLinked to original sources
PubMed2005

Morbidity and mortality following inadvertent poisoning with decanted chemicals.

Decanting of chemicals from their original containers is a hazardous practice that can result in inadvertent poisoning. We conducted a four-year prospective observational study to analyse the epidemiology of accidental poisoning with decanted chemicals. 157 patients were poisoned following accidental exposure to chemicals transferred to innocuous containers. 106 patients attended hospital emergency departments, 17 attended a general practitioner and 34 were instructed to seek medical advice if symptomatic. 112 patients developed clinical features, 9 patients required admission to intensive care and 4 of these needed intubation and ventilation. There was 1 fatality following inadvertent ingestion of paraquat. The predominant symptoms were gastrointestinal upset and a burning sensation in the mouth, throat, and stomach. Decanted chemicals included household, industrial, automobile, and agricultural products. Caustic agents accounted for approximately 33% of decanted chemicals. Decanting of chemicals into innocuous containers results in significant morbidity, mortality, and cost to the health service.

Accidents↗
PubMed2002

Bupropion (Zyban) toxicity.

Bupropion is a monocyclic antidepressant structurally related to amphetamine. Zyban, a sustained-release formulation of bupropion hydrochloride, was recently released in Ireland, as a smoking cessation aid. In the initial 6 months since it's introduction, 12 overdose cases have been reported to The National Poisons Information Centre. 8 patients developed symptoms of toxicity. Common features included tachycardia, drowsiness, hallucinations and convulsions. Two patients developed severe cardiac arrhythmias, including one patient who was resuscitated following a cardiac arrest. All patients recovered without sequelae. We report a case of a 31 year old female who required admission to the Intensive Care Unit for ventilation and full supportive therapy, following ingestion of 13.5g bupropion. Recurrent seizures were treated with diazepam and broad complex tachycardia was successfully treated with adenosine. Zyban caused significant neurological and cardiovascular toxicity in overdose. The potential toxic effects should be considered when prescribing it as a smoking cessation aid.

Adult↗
PubMed1998

Quantitative microscopic analysis of inflammation in rheumatoid arthritis synovial membrane samples selected at arthroscopy compared with samples obtained blindly by needle biopsy.

OBJECTIVE: To evaluate microscopic measures of inflammation in rheumatoid arthritis synovial tissue samples selected at arthroscopy compared with those obtained blindly by needle biopsy from the suprapatellar pouch (SPP) of the same joint. METHODS: Samples were selected at knee arthroscopy from the SPP and the lateral and medial gutters. Immediately following arthroscopy, a biopsy needle was inserted through the same portal into the SPP by a second investigator, and 3 further samples were obtained blindly. Using standard immunohistologic methods, all samples were analyzed by a single investigator without knowledge of the original tissue location and biopsy technique. Following staining with anti-CD3 and anti-CD68 monoclonal antibodies, T lymphocyte and macrophage infiltration were measured by quantitative analysis. RESULTS: Synovial tissues from 14 patients were analyzed. In comparing microscopic measures of inflammation using the 2 procedures, mean scores of lining cell depth and the percentage of CD68+ cells in the lining layer correlated positively (tau = 0.59, P = 0.003 and tau = 0.73, P = 0.0003, respectively). In the sublining layer, CD3+ cell counts also correlated significantly (tau = 0.71, P = 0.0004). Sublining CD68+ cell counts did not correlate. This was explained by the observation that CD68+ cell infiltration in areas adjacent to articular cartilage was significantly greater than in the SPP (P = 0.01), suggesting preferential trafficking to this site by macrophages, but not by T lymphocytes. Macroscopic appearance at arthroscopy did not predict microscopic features. CONCLUSION: Most microscopic measures of inflammation in synovial tissue samples obtained blindly from the SPP were similar to those determined in samples selected at arthroscopy. However, measurements in samples from the SPP may underestimate the intensity of macrophage infiltration in areas more adjacent to cartilage. These observations have important implications for future study of macrophage function in synovial tissue.

Arthritis, Rheumatoid↗
PubMed1997

Comparative analysis of transforming growth factor-beta isoforms 1-3 in human and rabbit dentine matrices.

Previous studies have implicated transforming growth factor-beta (s)(TGF-beta) in both development. Here TGF-beta isoforms in dentine extracellular matrix were analysed because these molecules may participate in dental issue repair. EDTA-soluble and collagenase-released fractions were isolated from human crown and root and rabbit incisor dentine samples and analysed for TGF-beta isoforms. TGF-beta(1) was the major isoform detected in all samples and the only isoform detected in human dentine samples. TGF-beta(2) was detected only in the collagenase-released fraction of rabbit incisor dentine and was present at low levels. TGF-beta(3) was detected in both EDTA-soluble and collagenase-released fractions of rabbit dentine. Greater levels of the TGF-beta(1) isoform were detected in the rabbit than human dentine samples and some differences in distribution amongst the two tissue fractions were observed between these species. The presence of these isoforms of TGF-beta in dentine may provide a reservoir of growth factor in the matrix that could participate in processes leading to tissue repair after injury.

Animals↗
PubMed1997

Informed consent from whom?

To obtain legally safe informed consent requires that the patient has a 'substantial understanding' of the proposed procedure and that the doctor obtaining the informed consent has sufficient knowledge to explain the nature of the procedure to the patient. In this paper we have shown that significant misunderstanding exists among non-specialist junior doctors of certain common orthopaedic procedures and conditions. Junior doctors often lack sufficient technical training to fully inform their patients and thus meet legal requirements. The implications of this are that the onus falls even more on specialists to ensure that their patients receive a more detailed explanation of the proposed intervention.

Arthroscopy↗
PubMed1995

Influence of substrate nature and immobilization of implanted dentin matrix components during induction of reparative dentinogenesis.

The biological effects of isolated soluble dentin extracellular matrix components on the induction of reparative dentinogenesis in exposed cavities in ferret canine teeth have been shown to be blocked by immobilizing the extracellular matrix components on nitrocellulose or Millipore membranes during implantation. This contrasts with the picture of induction of odontoblast-like cell differentiation and reparative dentin deposition on existing insoluble dentin matrix of the exposure walls when the extracellular matrix components are implanted in lyophilized form. These data indicate the importance of an existing insoluble dentin matrix in providing a substrate to potentiate the growth factor-like activity of soluble isolated dentin extracellular matrix components in the induction of reparative dentinogenesis.

Animals↗
PubMed1995

Reactionary dentinogenesis.

Reactionary dentinogenesis is the secretion of a tertiary dentine matrix by surviving odontoblast cells in response to an appropriate stimulus. Whilst this stimulus may be exogenous in nature, it may also be from endogenous tissue components released from the matrix during pathological processes. Implantation of isolated dentine extracellular matrix components in unexposed cavities of ferret teeth led to stimulation of underlying odontoblasts and a response of reactionary dentinogenesis. Affinity chromatography of the active components prior to implantation and assay for growth factors indicated that this material contained significant amounts of TGF-beta 1, a growth factor previously shown to influence odontoblast differentiation and secretory behavior. Reactionary dentinogenesis during dental caries probably results from solubilization of growth factors, TGF-beta in particular, from the dentine matrix which then are responsible for initiating the stimulatory effect on the odontoblasts. Compositional differences in tertiary dentine matrices beneath carious lesions in human teeth have also been shown indicating modulation of odontoblast secretion during reactionary and reparative dentinogenesis.

Animals↗
PubMed1994

Odontoblast stimulation in ferrets by dentine matrix components.

The possible effects of isolated dentine matrix components on odontoblast secretory activity were investigated in vivo by implantation of lyophilized fractions of these components into cavities prepared in ferret canine teeth. After implantations as short as 14 days there was significant deposition of reactionary dentine by the odontoblasts beneath the cavity and this response increased in a non-linear manner with time of implantation. In contrast, control cavities lacking the dentine matrix components showed no evidence of reactionary dentine deposition. Examination of teeth at early periods of implantation (2 and 5 days) indicated that odontoblast death had not occurred as a result of the operative procedures and that the response was one of stimulation of existing odontoblasts rather than that of induction of a new generation of odontoblast-like cells. The mechanisms of odontoblast stimulation by the dentine matrix components remain to be elucidated, but could be mediated by growth factors within the dentine matrix preparations.

Animals↗
PubMed1993

Role of magnetic resonance imaging in the assessment of spinal injuries.

Magnetic Resonance Imaging (MRI) examination was carried out on 44 patients who had spinal injuries with neurological involvement. The technique provided valuable information about the nature of the injuries and, in particular, about the state of the spinal cord. The appearances of the cord on MRI ranged from normal, to oedema, to more severe damage such as cord haemorrhage or transection or, in later cases, myelomalacia. The appearance of the cord on MRI correlated strongly with both the severity of the neurological deficit and also the degree of subsequent recovery. In the assessment of the acute spinal injury, MRI has been shown to be a good prognostic indicator; it may also help to identify which patients are likely to benefit from early decompression.

Acute Disease↗
PubMed1992

Perforation through undiagnosed small bowel involvement in primary thyroid lymphoma during chemotherapy.

A case is described of fatal perforation of the small bowel through an area of undiagnosed secondary involvement from primary thyroid lymphoma during treatment by chemotherapy. There is a known association between primary thyroid lymphoma and gastrointestinal metastases. To avoid this lethal complication, a specific search should be made for gastrointestinal involvement before chemotherapy is started in patients with advanced thyroid lymphoma.

Aged↗