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Biomedical subjects

M McElroy

Publications and source records attributed to M McElroy.

16 recordsLinked to original sources
PubMed2005

Clinical and pathological features of experimental scrapie in Irish Blackface Mountain sheep.

There have been no reports of natural scrapie in Irish Blackface Mountain (BM) sheep which account for approximately 16% of the Irish national sheep flock. The aim of this study was to determine if Irish BM sheep had unusual clinical and/or pathological features of scrapie which would account for failure to diagnose the disease in this breed. BM (n=7), Texel (n=3) and Suffolk sheep (n=1) of scrapie-susceptible PrP genotypes (ARQ/ARQ and VRQ/ARQ) were orally challenged with scrapie-infected brain inoculum. The incubation period, clinical signs, pathology and distribution of disease specific prion protein (PrP(d)) in scrapie-affected BM sheep were similar to scrapie in the Texel and Suffolk sheep. It was concluded that there was no evidence to suggest that scrapie in BM sheep differs clinicopathologically from scrapie in other breeds of sheep.

Animals↗
PubMed2004

Immunohistochemical studies of scrapie archival material from Irish ARQ/ARQ sheep for evidence of bovine spongiform encephalopathy-derived disease.

Since scrapie and bovine spongiform encephalopathy (BSE) in sheep are clinicopathologically indistinguishable, BSE in sheep may have been misdiagnosed as scrapie. Disease-specific prion protein (PrP(d)) patterns in archival tissues of 38 Irish ARQ/ARQ sheep diagnosed as scrapie-affected were compared to those in four Dutch BSE-challenged sheep. When medulla oblongata was immunolabelled with an antibody directed against amino acids 93-99 of ovine prion protein (ovPrP), intraneuronal PrP(d) was apparent in all 38 Irish sheep but was absent in BSE-challenged sheep. When lymphoid follicles were immunolabelled with antibodies directed against amino acids 93-106 of ovPrP, granule clusters of PrP(d) were seen in 34 of the 38 Irish sheep. Follicles of the remaining four archive sheep contained either no PrP(d) or single PrP(d) granules, similar to follicles from BSE-challenged sheep. Based on the medulla results, none of the archival cases had BSE-derived disease. The identification of some scrapie sheep with little or no intrafollicular PrP(d) suggests that this technique may be limited in discriminating between the two diseases.

Animals↗
PubMed2002

A framework for integrating the songbird brain.

Biological systems by default involve complex components with complex relationships. To decipher how biological systems work, we assume that one needs to integrate information over multiple levels of complexity. The songbird vocal communication system is ideal for such integration due to many years of ethological investigation and a discreet dedicated brain network. Here we announce the beginnings of a songbird brain integrative project that involves high-throughput, molecular, anatomical, electrophysiological and behavioral levels of analysis. We first formed a rationale for inclusion of specific biological levels of analysis, then developed high-throughput molecular technologies on songbird brains, developed technologies for combined analysis of electrophysiological activity and gene regulation in awake behaving animals, and developed bioinformatic tools that predict causal interactions within and between biological levels of organization. This integrative brain project is fitting for the interdisciplinary approaches taken in the current songbird issue of the Journal of Comparative Physiology A and is expected to be conducive to deciphering how brains generate and perceive complex behaviors.

Animals↗
PubMed2002

A novel nonsuppurative meningoencephalitis in young greyhounds in Ireland.

Fourteen 4- to 18-month-old vaccinated Greyhounds (10 males, 4 females) from three kennels in southern Ireland presented over a 2-year period with acute or insidious onset neurological signs. Head tilting, ataxia, recumbency, circling, and blindness were commonly observed, and animals were dull, dehydrated, and had lost weight. Hematologic and biochemical parameters reflected dehydration but were otherwise unremarkable. Microscopic examination revealed severe diffuse and focal gliosis and gemistocytosis accompanied by mononuclear cell perivascular cuffing in caudate nucleus and cortical gray matter of the cerebrum and in the periventricular gray matter of the anterior brainstem. Milder lesions were noted in the caudal brainstem, cranial spinal cord, and in the molecular layer of the cerebellum. This was accompanied by a lymphocyte and plasma cell infiltration of the cerebral and cerebellar meninges. Demyelination, neuropil necrosis, neuronophagia, and vasculitis were not observed. No inclusion bodies, fungi, or protozoal cysts were seen. Additional serologic and molecular pathology tests also failed to determine a cause, suggesting that these cases may represent a previously undiagnosed condition in the dog.

Animals↗
PubMed2000

Molecular analysis of Irish sheep scrapie cases.

Different strains of transmissible spongiform encephalopathies in humans and rodent models are associated with the accumulation of PrP(Sc) of distinct molecular characteristics. These characteristics include glycosylation profiles, fragment sizes and long-term resistance of PrP(Sc) to proteinase K. The first objective of this study was to determine the applicability of these criteria to characterize and differentiate sheep scrapie PrP(Sc) and bovine spongiform encephalopathy (BSE) PrP(Sc). PrP(Sc) in sheep scrapie samples from Ireland had clearly distinct molecular characteristics to PrP(Sc) in cattle BSE samples using a monoclonal antibody (MAb P4) directed to position 89-104 of ovine PrP using either brain homogenates or semi-purified scrapie-associated fibrils. Similar glycoprofiles were found when analysing scrapie PrP(Sc) in six different CNS regions (thoracic spinal cord, thalamus, basal ganglia, mediobasal hypothalamus, medulla oblongata and cortex). While the long-term resistance results using a different monoclonal antibody (raised to ruminant PrP positions 145-163; MAb L42) were similar to the results obtained with MAb P4, different glycotyping results were obtained. Given the variation in glycosylation patterns using different antibodies, we conclude that standardization of methodology and antibodies is crucial to the applicability of molecular analysis of ruminant BSE and scrapie samples.

Animals↗
PubMed1999

Density and substrata are important in lung type II cell transdifferentiation in vitro.

Morphological techniques and metabolic cell marker assays were used to study the transdifferentiation of pulmonary type II epithelial cells to type I-like cells in vitro. In the lung this process is important during remodelling and alveolar repair. Type II cell phenotype was best maintained over eight days when densely packed cells were plated out on a commercially available extracellular matrix. Such cells retained type II cell characteristics (lamellar bodies, high activities of gamma glutamyl transpeptidase and alkaline phosphatase) but expressed low levels of rT1(40) a surface protein marker of type I cells. In contrast, low density cultures, irrespective of substratum, exhibited rapid cell spreading, loss of lamellar bodies, loss of type II cell enzyme markers and expressed high levels or rT1(40). Conditions have been described whereby the same isolate of type II cells can be used to produce differential epithelial phenotypes and use can be made of this for further characterisation or to investigate the effect of toxins on different lung cell types in vitro.

Alkaline Phosphatase↗
PubMed1999

Leptin inhibits gonadotrophin-stimulated granulosa cell progesterone production by antagonizing insulin action.

Recent evidence has demonstrated that expression of leptin and leptin receptors is expected in the human ovary, and that leptin alters ovarian steroidogenesis in animal models. This study was designed to determine whether leptin modulates basal, gonadotrophin-, and insulin-stimulated progesterone production by human luteinized granulosa cells (GC). GC were recovered from follicular aspirates obtained during transvaginal ultrasound-guided oocyte retrieval for in-vitro fertilization-embryo transfer, and cultured in defined medium with various combinations of chorionic gonadotrophin (HCG; 0 or 100 ng/ml), insulin (0-30 microg/ml), and leptin (0-100 ng/ml). Progesterone concentrations in media were determined at various time points (2 h to 6 days). Leptin time- and dose-dependently inhibited (P < 0.05) HCG-stimulated progesterone production by human luteinized GC, but did not alter basal steroidogenesis. Moreover, the inhibitory effect of leptin on gonadotrophin-stimulated progesterone production was only manifested in the presence of insulin. Leptin suppression of insulin-supported steroidogenesis was also time- and dose-dependent. We conclude that leptin inhibits gonadotrophin-stimulated GC progesterone production apparently by antagonizing insulin action. Leptin suppression of progesterone production by human luteinized GC is consistent with recent data from animal models, and supports the possible role of leptin as a regulator of human ovarian function.

Cells, Cultured↗
PubMed1995

Assessment of a specimen mount for biopsy of impalpable breast lesions.

Biopsy of the impalpable breast lesion is an increasing part of the surgical workload as a result of the National Breast Cancer Screening Programme. A specimen mount card has been described to orientate such specimens in three dimensions prior to radiological and pathological examination. Experience with 243 biopsies in this unit has shown it to be a useful aid in determining completeness of excision. It may also be used as a guide to further surgery when excision is incomplete and breast conservation is the treatment option of choice.

Biopsy↗
PubMed1994

Should breast biopsy cavities be drained?

A total of 112 women was entered into a randomised study to investigate the effects of suction drainage on haematoma formation in breast biopsy wounds. Of 107 evaluable patients, 52 received drainage and 55 had no drain. The wounds were examined 1 week after operation when the volume of wound haematoma was measured using ultrasonography. Haematomas were present in 48 (87%) patients with undrained wounds compared with 34 (65%) patients with drained wounds (P = 0.014, chi 2 test). Median haematoma volume was 20 ml (range 0-172.5 ml) in the undrained group compared with 2 ml (range 0-100 ml) in the drained group (P = 0.001, Mann-Whitney U test). There was one wound infection in each group. There was no difference in median pain score or duration of pain between the groups. While suction drainage significantly reduces the incidence and volume of wound haematomas, this does not appear to influence outcome.

Adult↗
PubMed1991

27-year mortality in the Western Collaborative Group Study: construction of risk groups by recursive partitioning.

The relationship of selected biological and behavioral characteristics measured at baseline examination to 27-year mortality due to coronary heart disease (CHD), cancers of all sites, and total mortality in the 3154 men that form the Western Collaborative Group Study was investigated using tree-structured survival analysis or recursive partitioning (RP). Intake (1960-61) characteristics included in the present analyses were age, serum cholesterol, systolic blood pressure (SBP), cigarette smoking, body mass index (BMI), Type A/B behavior, and behavioral hostility. Tree-structured survival analysis for CHD mortality partitioned the cohort into six groups and identified five groups with distinct survival experience. Exceptionally high CHD mortality rates (17.3 and 14.6 per thousand) were experienced by 89 older men with elevated hostility ratings and SBP less than or equal to 150, and 238 men whose initial SBP was greater than 150 mmHg. Younger men (age less than or equal to 48) with SBP less than or equal to 150 and with serum cholesterol levels greater than 227 had a death rate of 4.8 per thousand, compared with a rate of 1.7 in similar men with lower cholesterol levels. Applied to 27-year cancer mortality, the RP algorithm partitioned the cohort into four distinct survival groups. Younger (age less than 45) Type B men had superior survival compared with Type A men of similar ages, and the proportion of ever cigarette smokers in these two groups was not statistically different. The results obtained by tree-structured survival analyses were compared with results obtained by Cox regression survival analyses.

Adult↗
PubMed1988

Long-term efficacy of mexiletine alone and in combination with class Ia antiarrhythmic drugs for refractory ventricular arrhythmias.

The efficacy of mexiletine used alone, and in combination with a class Ia antiarrhythmic drug, was assessed in 159 previously drug-refractory patients with ventricular tachycardia (VT) during serial electrophysiologic studies and during long-term (5-year) clinical follow-up. Electrically-inducible ventricular tachycardia was suppressed by mexiletine alone in 23% of patients tested, and a combined antiarrhythmic drug regimen was effective in 29% of the trials performed. Mexiletine was much more likely to be effective in patients presenting with nonsustained VT or ventricular fibrillation than in patients with sustained VT (p less than 0.005). After 1 and 4 years of treatment, 18% and 42% of the patients treated with mexiletine alone had died suddenly or suffered recurrent symptomatic VT, compared to 11% and 25% of patients treated with the combined antiarrhythmic drug regimens (p = NS). Mexiletine therapy was associated with frequent, though readily reversible, adverse reactions. However, mexiletine treatment had to be discontinued permanently in 8 of 92 patients (9%) because of intolerable side effects. We conclude that the added efficacy and possible improved arrhythmia-free survival associated with combining mexiletine with a class Ia agent should be further investigated.

Anti-Arrhythmia Agents↗
PubMed1976

Bone disease in long-term haemodialysis: the association of radiological with histological abnormalities.

The radiological findings in the skeletal surveys of 70 patients receiving long-term haemodialysis for chronic renal failure have been correlated with histological findings in a specimen obtained by biopsy of the iliac crest. Many significant associations were found, and the ones presented are those thought to be most useful in the interpretation of the radiological abnormalities. The main conclusions are that fractures and severe medullary rarefaction appear to be most commonly the result of osteomalacia; subperiosteal erosions are associated with the more severe grades of osteitis fibrosa; cortical striations and sclerosis are associated with an increased amount of osteoid, and sclerosis is diagnosed more frequently by radiological means than by iliac-crest biopsy.

Adult↗