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Biomedical subjects

B M Corcoran

Publications and source records attributed to B M Corcoran.

At least 19 recordsLinked to original sources
PubMed2007

Growth of probiotic lactobacilli in the presence of oleic acid enhances subsequent survival in gastric juice.

The effect of inclusion of various C18 fatty acids with 0-2 double bonds in either cis or trans configuration on Lactobacillus rhamnosus GG survival was analysed in simulated gastric juice at pH 2.5. The incorporation of Tween 80 (1 g l-1) in the growth media enhanced subsequent survival of stationary-phase cultures up to 1000-fold following 90 min acid exposure compared with controls grown without Tween 80. There was a significant (P<0.05) increase in bacterial content of oleic acid [C18:1 (9c), up to 55-fold] after growth of bacteria in MRS supplemented with Tween 80. The inclusion of various C18 fatty acids in the growth media revealed that only oleic and vaccenic acids [C18:1 (11t)] had protective effects on the survival of Lb. rhamnosus GG when exposed to the acidic environment. Comparative analysis with other lactobacilli indicated that all strains exhibited increased survival when grown in the presence of Tween 80. Further work with a neomycin-resistant mutant with 48% of the F0F1-ATPase activity of the parent indicated that the Tween 80 effect was independent of the complex. The mechanisms behind the effect of fatty acid protection were investigated and proton permeability assays showed that cultures grown in the presence of Tween 80 had higher extracellular pH than controls. Furthermore, there was a significant reduction of oleic acid and a significant increase in stearic acid (C18:0) (P<0.05) content of bacterial cells following exposure of Tween 80-supplemented cultures to simulated gastric juice. Overall, the data suggest that probiotic lactobacilli can use an exogenous oleic acid source to increase their acid survival and the underlying mechanism most likely involves the ability of increased membrane oleic acid to be reduced by H+ to stearic acid.

Culture Media↗
PubMed2006

Enhanced survival of GroESL-overproducing Lactobacillus paracasei NFBC 338 under stressful conditions induced by drying.

GroESL-overproducing Lactobacillus paracasei NFBC 338 was dried, and its viability was compared with that of controls. Spray- and freeze-dried cultures overproducing GroESL exhibited approximately 10-fold and 2-fold better survival, respectively, demonstrating the importance of GroESL in stress tolerance, which can be exploited to enhance the technological performance of sensitive probiotic cultures.

Bacterial Proteins↗
PubMed2005

Efficacy and safet of pimobendan in canine heart failure caused by myxomatous mitral valve disease.

OBJECTIVES: To evaluate the clinical efficacy and safety of pimobendan by comparing it with ramipril over a six-month period in dogs with mild to moderate heart failure (HF) caused by myxomatous mitral valve disease (MMVD). METHODS: This was a prospective randomised, single-blind, parallel-group trial. Client-owned dogs (n = 43) with mild to moderate HF caused by MMVD were randomly assigned to one of two groups, which received either pimobendan (P dogs) or ramipril (R dogs) for six months. The outcome measures studied were: adverse HF outcome, defined as failure to complete the trial as a direct consequence of HF; maximum furosemide dose (mg/kg/day) administered during the study period; and any requirement for additional visits to the clinic as a direct consequence of HF. RESULTS: Treatment with pimobendan was well tolerated compared with treatment with ramipril. P dogs were 25 per cent as likely as R dogs to have an adverse HF outcome (odds ratio 4.09, 95 per cent confidence interval 1.03 to 16.3, P = 0.046). CLINICAL SIGNIFICANCE: R dogs had a higher overall score and thus may have had more advanced disease than P dogs at baseline (P = 0.04). These results should be interpreted cautiously but such a high odds ratio warrants further investigation.

Animals↗
PubMed2005

Thoracic high-resolution computed tomographic findings in dogs with canine idiopathic pulmonary fibrosis.

OBJECTIVES: To identify features of canine idiopathic pulmonary fibrosis (CIPF) using high-resolution computed tomography (HRCT), and to correlate these features with clinical stages of the disease. METHODS: Ten dogs with signalment, history and clinical signs highly suggestive of CIPF were investigated. Thoracic radiography, haematology and biochemistry profiles, bronchoscopy and bronchoalveolar lavage and HRCT were performed in each case. The dogs were classified as having mild, moderate or severe stages of the disease based on their clinical presentation and radiographic signs. Features identified by HRCT were correlated with these disease stages. RESULTS: HRCT showed a spectrum of pulmonary changes and it was possible to match some of these to the stage of CIPF. CLINICAL SIGNIFICANCE: HRCT is used extensively in humans in the diagnosis and treatment planning of idiopathic pulmonary fibrosis. This preliminary study identifies the high-resolution computed tomographic features of CIPF in a small group of dogs. With further work it may be possible to use HRCT as a non-invasive tool for diagnosing, staging and therapeutically monitoring CIPF.

Animals↗
PubMed2005

Survival of probiotic lactobacilli in acidic environments is enhanced in the presence of metabolizable sugars.

Lactobacillus rhamnosus GG is an industrially significant probiotic strain with proven health benefits. In this study, the effect of glucose on L. rhamnosus GG survival was analyzed in simulated gastric juice at pH 2.0. It was found that the presence of 19.4 mM glucose resulted in up to 6-log10-enhanced survival following 90 min of exposure. Further work with dilute HCl confirmed that glucose was the sole component responsible. Comparative analysis with other Lactobacillus strains revealed that enhanced survival was apparent in all strains, but at different pH values. The presence of glucose at concentrations from 1 to 19.4 mM enhanced L. rhamnosus GG survival from 6.4 to 8 log10 CFU ml(-1) in simulated gastric juice. The mechanisms behind the protective effect of glucose were investigated. Addition of N',N'-dicyclohexylcarbodiimide to simulated gastric juice caused survival to collapse, which was indicative of a prominent role in inhibition of F0F1-ATPase. Further work with neomycin-resistant mutants that exhibited 38% to 48% of the F0F1-ATPase activity of the parent confirmed this, as the survival in the presence of glucose of these mutants decreased 3 x 10(6)-fold compared with the survival of the wild type (which had a viability of 8.02 log10 CFU ml(-1)). L. rhamnosus GG survival in acidic conditions occurred only in the presence of sugars that it could metabolize efficiently. To confirm the involvement of glycolysis in the glucose effect, iodoacetic acid was used to inhibit glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity. The reduction in GAPDH activity caused survival to decrease by 8.30 log10 CFU ml(-1) in the presence of glucose. The data indicate that glucose provides ATP to F0F1-ATPase via glycolysis, enabling proton exclusion and thereby enhancing survival during gastric transit.

Adenosine Triphosphate↗
PubMed2004

Comparative survival of probiotic lactobacilli spray-dried in the presence of prebiotic substances.

AIMS: Probiotic milk-based formulations were spray-dried with various combinations of prebiotic substances in an effort to generate synbiotic powder products. METHODS AND RESULTS: To examine the effect of growth phase and inclusion of a prebiotic substance in the feed media on probiotic viability during spray-drying, Lactobacillus rhamnosus GG was spray-dried in lag, early log and stationary phases of growth in reconstituted skim milk (RSM) (20% w/v) or RSM (10% w/v), polydextrose (PD) (10% w/v) mixture at an outlet temperature of 85-90 degrees C. Stationary phase cultures survived best (31-50%) in both feed media and were the most stable during powder storage at 4-37 degrees C over 8 weeks, with 30-140-fold reductions in cell viability at 37 degrees C in RSM and PD/RSM powders, respectively. Stationary phase Lact. rhamnosus GG was subsequently spray-dried in the presence of the prebiotic inulin in the feed media, composed of RSM (10% w/v) and inulin (10% w/v), and survival following spray-drying was of the order 7.1-43%, while viability losses of 20,000-90,000-fold occurred in these powders after 8 weeks' storage at 37 degrees C. Survival of the Lactobacillus culture after spray-drying in powders produced using PD (20% w/v) or inulin (20% w/v) as the feed media was only 0.011-0.45%. To compare different probiotic lactobacilli during spray-drying, stationary phase Lact. rhamnosus E800 and Lact. salivarius UCC 500 were spray-dried using the same parameters as for Lact. rhamnosus GG in either RSM (20% w/v) or RSM (10% w/v) and PD (10% w/v). Lact. rhamnosus E800 experienced approx. 25-41% survival, yielding powders containing approximately 10(9) CFU g(-1), while Lact. salivarius UCC 500 performed poorly, experiencing over 99% loss in viability during spray-drying in both feed media. In addition to the superior survival of Lact. rhamnosus GG after spray-drying, both strains experienced higher viability losses (570-700-fold) during storage at 37 degrees C over 8 weeks compared with Lact. rhamnosus GG. CONCLUSIONS: Stationary phase cultures were most suitable for the spray-drying process, while lag phase was most susceptible. The presence of the prebiotics PD and inulin did not enhance viability during spray-drying or powder storage. SIGNIFICANCE AND IMPACT OF THE STUDY: High viability (approximately 10(9) CFU g(-1)) powders containing probiotic lactobacilli in combination with prebiotics were developed, which may be useful as functional food ingredients for the manufacture of probiotic foods.

Animals↗
PubMed2003

Changes in nasal mucosal innervation in horses with grass sickness.

REASONS FOR PERFORMING STUDY: Equine grass sickness is a dysautonomia characterised by widespread destruction of autonomic ganglia, resulting in the clinical signs of dysphagia, constipation, profuse sweating, tachycardia, rhinitis sicca and high mortality rate. Rhinitis sicca is a common finding in horses with the chronic form and we have postulated that alterations in autonomic innervation of the nasal mucosa might underlie this clinical presentation. OBJECTIVES: In this study, the expression and distribution of nerve fibres immunoreactive for calcitonin gene-related peptide (CGRP), substance P (SP), the general neuronal marker protein gene-product 9.5 (PGP 9.5; ubiquitin) and the intermediate neurofilaments (PAN-N; neurorfilaments L, M and H) in the nasal mucosa of normal horses (n = 10) and horses with EGS (n = 18; acute n = 8, subacute n = 3, chronic n = 7) was assessed. METHODS: Innervation density and distribution was investigated in the different groups using standard immunohistochemical techniques. RESULTS: Significant differences were noted when comparing the density and distribution of nerve fibres immunoreactive for PGP 95 and PAN-N, with PGP 95 consistently giving better staining in all groups and at all sites in the nasal mucosa. An apparent increase in the density of innervation was noted for acute vs. normal cases. A significant reduction in the density of innervation was noted only with PAN-N when comparing normal horses and acute cases with the chronic group (P < 0.05). CGRP and SP immunoreactive nerve fibres were typically most abundant in the epithelial and subepithelial layers, but the quality of staining and nerve fibre density was greater for SP, achieving significant difference in several comparisons. The density of innervation for SP was significantly reduced in the chronic group compared to the normal and acute groups (P < 0.01). A significant decrease was noted for CGRP only for the acute and chronic groups (P<0.05). CONCLUSIONS: These results demonstrate a reduction in the expression of the sensory neuropeptides in nasal mucosal innervation as a consequence of equine dysautonomia, and may underlie the clinical presentation of rhinitis sicca noted with this disease. POTENTIAL RELEVANCE: Nasal biopsy may be of use in antemortem diagnosis of grass sickness and identification of mucosal denervation; and might also be useful in the treatment of rhinitis in EGS cases.

Acute Disease↗
PubMed2002

Review of left-to-right shunting patent ductus arteriosus and short term outcome in 98 dogs.

The case records of 98 dogs with a left-to-right shunting patent ductus arteriosus (PDA) were reviewed. There were 35 breeds represented, with a female to male ratio of 3:1. Forty per cent of the dogs were older than one year at initial presentation and 31 per cent had clinical signs attributable to PDA. A left heart base continuous murmur of grade IV/VI or higher was noted in 90 per cent of the dogs. On electrocardiography, the most common abnormalities were tall R waves (63 per cent) and deep QII waves (62 per cent). The radiographic triad of dilation of the descending aorta with enlargement of the main pulmonary artery segment and left atrium, typical of PDA, was noted in only 26 per cent of cases. Two-dimensional (2D) and M-mode echocardiography detected left atrial enlargement (35 per cent) and an increased left ventricular diameter in diastole (82 per cent) and systole (84 per cent) as the most common abnormalities. Doppler echocardiography demonstrated increased aortic outflow velocities in 66 per cent of cases. The overall short-term successful outcome in this study was 95 per cent. There was no significant difference between surgical ductal ligation using a standard technique or the Jackson-Henderson technique in terms of survival, occurrence of haemorrhage or residual shunting. The number of interventional procedures used in this study was too low for statistical comparison, but there appeared to be a trend towards a higher rate of residual shunting and a lower fatality rate using a coil occlusion technique.

Animals↗
PubMed2001

Sick sinus syndrome in nine West Highland white terriers.

Sick sinus syndrome is a clinical term used to describe the clinical signs of sinus node dysfunction. This paper describes the clinical data from nine West Highland white terriers, eight females and one male, in which a diagnosis of sick sinus syndrome was made. The most common clinical signs were episodic weakness and presyncope. Electrocardiographic findings included sinus bradycardia, sinus arrest with or without escape complexes, disturbances of atrioventricular conduction, paroxysmal supraventricular tachycardia, or some combination of these dysrhythmias. The main radiographic changes were mild right-sided cardiomegaly in five cases, and a slight increase in bronchial and interstitial markings in four, but there was no evidence of congestive heart failure in any of the dogs. Echocardiography revealed mild to moderate mitral endocardiosis in three cases with no other significant abnormalities. The dogs' responses to parenteral atropine were variable and were not necessarily related to their response to oral anticholinergic agents. Five of the dogs were initially treated with propantheline bromide, but in only two of them were the clinical signs controlled in the long term. Six of the dogs were successfully treated by the implantation of a transvenous pacemaker.

Animals↗
PubMed2001

Immunohistochemical study of the distribution of adrenergic and peptidergic innervation in the equine uterus and the cervix.

Little is known about neurogenic regulation of uterine contractility in mares. The present study investigated the distribution of adrenergic and peptidergic nerves in the mare uterus. Samples from the uterine horn, body and cervix were collected from 18 cyclic mares for immunohistochemistry. The uterus was well supplied with adrenergic nerves. A large number of tyrosine hydroxylase- and dopamine beta-hydroxylase-immunoreactive nerve bundles and fibres were present in the myometrium and endometrium in all regions of the uterus and cervix. These adrenergic nerve bundles and fibres travelled parallel to the muscle layers and were often associated with blood vessels. The density of peptidergic nerves was less than that of adrenergic nerves, but the pattern of distribution was similar. Neuropeptide Y-immunoreactive nerve fibres were the most abundant, whereas vasoactive intestinal polypeptide- and calcitonin gene-related peptide-immunoreactive nerve fibres were less frequently seen. Substance P-immunoreactive nerve fibres were the most sparse. Peptidergic nerves were distributed among the smooth muscle layers and near endometrial glands and were often associated with blood vessels in all regions of the uterus. The density of peptidergic nerve fibres was similar in the uterine horn and body but was slightly denser in the cervix. These findings indicate that uterine innervation may have an important role in controlling reproductive functions in mares.

Animals↗
PubMed2000

Spontaneous laryngeal paralysis in four white-coated German shepherd dogs.

Four cases of spontaneous laryngeal paralysis in juvenile white-coated German shepherd dogs are described. The presenting signs were typical for laryngeal paralysis, with stridor present in all four cases. Laryngoscopy revealed bilateral laryngeal paralysis in three cases, and unilateral paralysis in one. Concurrent megaoesophagus was also identified in one dog. All dogs underwent surgical treatment for laryngeal paralysis. Euthanasia was performed in one case due to intractable regurgitation and aspiration pneumonia. A possible association with white coat colour is discussed.

Animals↗
PubMed2000

Expression of vasoactive intestinal peptide, calcitonin gene-related peptide, substance P, and intermediate neurofilaments in nasal mucosal nerve fibers of horses without nasal disease.

OBJECTIVE: To determine the distribution of nerve fibers containing calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal peptide (VIP), and intermediate neurofilaments in nasal mucosa of horses. ANIMALS: 6 horses without evidence of nasal disease. PROCEDURE: Full-thickness nasal tissue specimens were obtained from the rostral portion of the nasal septum at necropsy, and fluorescence immunohistochemistry was performed to assess mucosal distribution of nerve fibers. RESULTS: Nerve fibers with CGRP-like immunoreactivity (CGRP-Li) formed a dense subepithelial network, and a large number of fibers were found coursing between epithelial cells. Fibers with CGRP-Li were also associated with blood vessels and mucous glands. Fibers with SP-like immunoreactivity (SP-Li) had a similar distribution and density. In contrast, there were few fibers with VIP-like immunoreactivity. Fibers containing intermediate neurofilaments were prominent and appeared as large nerve fiber bundles mainly adjacent to the nasal septum but also close to mucous glands and within the lamina propria. Intermediate neurofilaments were also identified in single nerve fibers at all sites, but the density of fibers with intermediate neurofilaments did not match that of fibers with CGRP- or SP-Li. CONCLUSIONS: The density and distribution of nerve fibers containing SP- or CGRP-Li in nasal mucosa of horses was similar to that reported for other species. However, expression of VIP in nerve fibers was low. Antibodies against intermediate neurofilaments identified many nerve fibers in nasal mucosa of horses but did not appear to identify small diameter fibers expressing SP or VIP.

Animals↗
PubMed1999

Chronic pulmonary disease in West Highland white terriers.

This paper describes the clinical features, and diagnostic findings of a chronic respiratory condition in 29 West Highland white terriers. Typically, the dogs were coughing chronically, had dyspnoea and tachypnoea of varying severity, and had deteriorated progressively over months to years. The mean (sem) survival time in months from the clinical signs being first noted by the owners was 17.9 (2.3). Most cases had a combination of respiratory signs, but coughing was the predominant sign in 18 cases. Inspiratory crackles were audible on chest auscultation in 28 cases, 10 of which were also wheezing. Rhonchi were the predominant sound in the remaining case. The main radiographic changes were mild to severe increased Interstitial markings in all cases, with additional bronchial markings in 14 of the dogs. Right-sided cardiomegaly (cor pulmonale) was recorded in 15. Bronchoscopic findings in 17 of the dogs were either normal or involved a mild airway mucoid reaction in eight. Chronic mucosal changes were observed in eight, but in two this finding was equivocal. Dynamic changes to the lumen of the airway were present in seven cases. No significant haematological or biochemical changes could be detected in 20 cases, but four cases were hypercholestrolaemic. A histopathological assessment of four cases revealed alveolar septal fibrosis to be the predominant change. Prednisolone, with or without bronchodilators, was the most commonly used therapy, and the response was variable. The condition appears to be associated with significant pulmonary interstitial fibrosis of unknown aetiology and has clinical similarities to idiopathic pulmonary fibrosis (cryptogenic fibrosing alveolitis) in human beings.

Animals↗
PubMed1999

Obstructive inflammatory laryngeal disease in three cats.

Three cats with upper respiratory tract obstruction due to laryngeal inflammation are presented. Cervical radiography showed the presence of a soft tissue mass in the laryngeal region in all cases, and laryngoscopy allowed direct visualization of a mass associated with the larynx. Laryngeal samples were obtained by a combination of fine needle aspiration, cutting biopsy forceps, by ventral laryngotomy, and at post-mortem. Histopathology of the laryngeal samples showed the presence of a predominantly granulomatous inflammation, with macrophage and lymphocyte infiltration. One case was euthanased due to severe dyspnoea. The remaining two cases underwent combined medical (corticosteroid and antibiotic) and surgical (permanent tracheostomy or excision of laryngeal tissue by ventral laryngotomy) treatment. One case died of an undetermined cause 15 weeks after surgery while the other case remains clinically well 20 months after diagnosis. Recognition of the existence of granulomatous laryngitis is important as clinical signs and radiographic findings are indistinguishable from laryngeal neoplasia.

Animals↗
PubMed1999

The distribution of nerve fibres immunoreactive for vasoactive intestinal peptide, calcitonin gene-related peptide, substance P and dopamine beta-hydroxylase in the normal equine larynx.

The autonomic innervation of the mammalian respiratory system is complex, and involves a wide variety of peptide and non-peptide neurotransmitters which will have an important role in normal laryngeal function and the response to disease. This innervation has been partially described in the horse airway and lung, but there is no information on the equine larynx. This paper describes the expression and distribution of nerve fibres immunoreactive for vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP), substance P (SP) and the adrenergic enzymatic marker dopamine beta-hydroxylase (DBetaH) in the mucosa of the equine larynx. The overall relative density of nerve fibres immunoreactive for the different antigens was VIP>>CGRP>SP>>DBetaH. There were differences in the distribution of nerve fibre types, although each antigen was found in nerve fibres adjacent to blood vessels and mucous glands. VIP -like immunoreactivity (VIP -Li) was particularly extensive in association with mucous glands. SP - and CGRP -like immunoreactivity (SP -Li, CGRP -Li) were also seen close to the epithelium, with occasional nerve fibres coursing beneath and between the epithelial cells. Fragments of SP -Li and CGRP -Li fibres were also present in large nerve fibre bundles and ganglionic cell clusters, but not in the neurons themselves. The density of nerve fibres immunoreactive for DBetaH was very low and restricted to blood vessels and mucous glands. There was marked variation in the density of nerve fibres at the different sites, with the greatest density, particularly for VIP, over the arytenoid cartilage. Immunoreactive nerve fibres were less plentiful over the epiglottis, and the density of all types of nerve fibres was low over the cricoid cartilage. Overall VIP -Li nerve fibres were the most plentiful.

Animals↗
PubMed1999

Idiopathic pulmonary fibrosis in a Staffordshire bull terrier with hypothyroidism.

Radiographic evidence of chronic interstitial lung changes, usually believed to be attributable to lung fibrosis, is readily recognised in canine practice. Furthermore, there is a body of anecdotal evidence suggesting that a specific clinical entity consistent with chronic lung fibrosis occurs in specific breeds of terrier dogs. However, there is little pathological data to confirm these radiographic and clinical findings and, therefore, chronic interstitial lung disease of dogs is poorly characterised. In this report, a case of chronic pulmonary fibrosis is described in which histopathological confirmation was possible, and suggested that the condition might be analogous to idiopathic pulmonary fibrosis (cryptogenic fibrosing alveolitis) in humans.

Animals↗
PubMed1996

Distribution of calcitonin gene-related peptide, vasoactive intestinal polypeptide, neuropeptide Y, substance P and dopamine beta-hydroxylase immunoreactive nerve fibres in the trachea of sheep.

The distribution of nerve fibres containing calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), substance P (SP) and the catecholamine enzyme marker dopamine beta-hydroxylase (DBH) in the trachea of sheep was investigated by immunohistochemical methods. A semi-quantitative assessment of the extent of the nerve fibres immunoreactive for the various antigens was also made. Moderate to large numbers of CGRP-like immunoreactive (CGRP-Li) nerve fibres were present in all parts of the trachea including the epithelial layer, lamina propria, smooth muscle, closer to the mucous glands and blood vessels, and in the elastic fibre connective tissue layer. Although SP-Li nerve fibres had a similar distribution to CGRP, they were absent from the epithelial layer and only small numbers of fibres were present in other areas. Moderate numbers of VIP-Li fibres were present in the smooth muscle and close to mucous glands and blood vessels. Moderate numbers of NPY-Li fibres were present in the smooth muscle with smaller numbers close to mucous glands and blood vessels. Large numbers of DBH-Li nerve fibres were present in the smooth muscle and they had a similar distribution to NPY. The presence of both NPY and DBH in most DBH-Li nerve fibres was established by a double-straining technique, but not all the DBH-Li fibres contained NPY. The DBH/NPY-Li nerve fibres in the smooth muscle formed an extensive and dense interconnecting network and were the most common types of nerve fibres observed.

Animals↗