PubMed Health⌕ Search

Biomedical subjects

D Prince

Publications and source records attributed to D Prince.

16 recordsLinked to original sources
PubMed2003

Characterization of Vibrio fluvialis-like strains implicated in limp lobster disease.

Studies were undertaken to characterize and determine the pathogenic mechanisms involved in a newly described systemic disease in Homarus americanus (American lobster) caused by a Vibrio fluvialis-like microorganism. Nineteen isolates were obtained from eight of nine lobsters sampled. Biochemically, the isolates resembled V. fluvialis, and the isolates grew optimally at 20 degrees C; none could grow at temperatures above 23 degrees C. The type strain (1AMA) displayed a thermal reduction time (D value) of 5.77 min at 37 degrees C. All of the isolates required at least 1% NaCl for growth. Collectively, the data suggest that these isolates may embody a new biotype. Pulsed-field gel electrophoresis (PFGE) analysis of the isolates revealed five closely related subgroups. Some isolates produced a sheep hemagglutinin that was neither an outer membrane protein nor a metalloprotease. Several isolates possessed capsules. The isolates were highly susceptible to a variety of antibiotics tested. However, six isolates were resistant to erythromycin. Seventeen isolates harbored plasmids. Lobster challenge studies revealed that the 50% lethal dose of a plasmid-positive strain was 100-fold lower than that of a plasmid-negative strain, suggesting that the plasmid may enhance the pathogenicity of these microorganisms in lobsters. Microorganisms that were recovered from experimentally infected lobsters exhibited biochemical and PFGE profiles that were indistinguishable from those of the challenge strain. Tissue affinity studies demonstrated that the challenge microorganisms accumulated in heart and midgut tissues as well as in the hemolymph. Culture supernatants and polymyxin B lysates of the strains caused elongation of CHO cells in tissue culture, suggesting the presence of a hitherto unknown enterotoxin. Both plasmid-positive and plasmid-negative strains caused significant dose-related intestinal fluid accumulations in suckling mice. Absence of viable organisms in the intestinal contents of mice suggests that these microorganisms cause diarrhea in mice by intoxication rather than by an infectious process. Further, these results support the thermal reduction data at 37 degrees C and suggest that the mechanism(s) that led to fluid accumulation in mice differs from the disease process observed in lobsters by requiring neither the persistence of viable microorganisms nor the presence of plasmids. In summary, results of lobster studies satisfy Koch's postulates at the organismal and molecular levels; the findings support the hypothesis that these V. fluvialis-like organisms were responsible for the originally described systemic disease, which is now called limp lobster disease.

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↗
PubMed1997

Removal of Mycobacterium species by breathing circuit filters.

Breathing circuit filters (BCFs) are used in respiratory and critical-care settings for humidification of air and to limit transmission of respiratory pathogens. Three types of BCFs (Pall BB 25A, BB 100, and HME 15-22) were evaluated (in triplicate) for removal of Mycobacterium species. Filters were challenged with aerosolized Mycobacterium bovis (a surrogate for Mycobacterium tuberculosis), at minimum total concentrations of 10(4) colony-forming units. No M bovis was recovered in the effluent, providing removal efficiencies of > 99.99% to > 99.999% for the filters tested.

Anesthesiology↗
PubMed1995

Teaching Spanish to emergency medicine residents.

OBJECTIVE: To determine the effects of teaching medical Spanish to eight PGY1 emergency medicine residents on their subsequent interactions with Spanish-speaking patients. METHODS: Eight PGY1 residents completed a 45-hour medical Spanish course administered during their first residency month. Thirty-four subsequent physician-patient interactions by these residents were audiotaped over a six-month period at a suburban teaching ED. The tapes were transcribed and analyzed for errors by a professional medical Spanish interpreter and a native Spanish speaker. RESULTS: Minor errors (e.g., technically incorrect grammar or vocabulary with generally appropriate patient understanding) were found in more than half of the interactions and major errors (e.g., misunderstanding duration of symptoms, misunderstanding of vocabulary) were found in 14% of the interactions. In addition, although the course was designed to supplement, not replace, professional interpreters, the residents called for an interpreter only 46% of the time. CONCLUSION: Although medical language courses may be a useful adjunct to interpreters, they are not designed to replace them. Significant errors may occur when participants in such courses assume their knowledge is sufficient to obtain a good history, give patient release instructions, and provide medical care in general without an interpreter present.

Adolescent↗
PubMed1995

Audit of the value of double reading magnetic resonance imaging films.

100 consecutive magnetic resonance imaging (MRI) examinations were reviewed independently by two radiologists. Patients were selected so that the anatomical areas of clinical interest coincided with the special interests of the reviewers. The reviewers were both consultant radiologists, one with 3 years' and the other with 6 years' experience of MRI. Hard copy images from the MRI examinations were reported independently by both reviewers. Of the 100 MRI examinations, there was full concordance of opinion in 61/100. Of the remaining 39 cases, four (10%) were considered "minor unrelated" differences, 12 (31%) "minor related" differences and 23 (59%) "major related" differences resulting in a significant change in patient management.

Humans↗
PubMed1988

Severe diabetes induced in subtotally depancreatized dogs by sustained hyperglycemia.

Chronic clamping of plasma glucose levels at greater than or equal to 250 mg/dl in four partially depancreatized but previously nondiabetic dogs was followed within 2 wk by persistent hyperglycemia and glycosuria of less than or equal to 500 g/day, ketonuria, and weight loss. Three of the four dogs required daily insulin injections to control these catabolic manifestations. There was no evidence of spontaneous improvement of the severe diabetic state during the 39-69 days of observation after discontinuation of intravenous glucose infusion. Impairment of intravenous glucose tolerance, loss of the insulin response to glucose and arginine, fasting hyperglucagonemia, exaggerated glucagon responsiveness to arginine, and a significant reduction in sensitivity to insulin were characteristic of all diabetic dogs. Morphometric analysis of the endocrine pancreas revealed a profound reduction in the number and size of identifiable islets of the hyperglycemic dogs compared with islets from their own pancreases resected months earlier and with those from pancreatic remnants of eight subtotally depancreatized control dogs that had not been subjected to chronic hyperglycemic clamping. The reduction in number and size of islets of the hyperglycemic dogs was largely the consequence of depletion of insulin-containing cells and was similar to that of dogs with long-standing alloxan-induced diabetes. In the eight control dogs, clinical evidence of diabetes did not develop during a follow-up period of 193-296 days. In this group, there was no evidence of diminution of intravenous glucose tolerance, of the insulin response to glucose or arginine, or of insulin sensitivity as determined by an acute hyperinsulinemic hyperglycemic clamp. The number and size of islets and number of beta-cells in pancreatic remnants from these dogs did not differ morphometrically from those of the pancreatic segment that had been resected. We conclude that in subtotally depancreatized but nondiabetic dogs, maintenance of constant hyperglycemia of greater than or equal to 250 mg/dl by means of intravenous glucose infusion causes a severe, persistent, and often insulin-requiring diabetic state that does not occur in the absence of the hyperglycemia.

Animals↗
PubMedDate not supplied

Characteristics of PAHs, PCDD/Fs and PCBs in sediment following forest fires in northern Alberta.

Extensive forest fires occurred in northern Alberta, Canada, in 1998. Polynuclear aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) were studied following these forest fires in order to explore natural and anthropogenic influences on the affected forest fire area. Specifically, concentrations and profiles of these compounds were determined in sediment samples. A predominance of alkylated PAH derivatives over parent PAHs were observed at the burned and reference sites. Naturally dervied PAHs were abundant at all sites. A high proportion and concentration of retene was observed at the totally burned site and indicates some inputs from forest fires. Very low concentrations of PCDD/Fs and PCBs were observed at all sites, and the profiles were very similar. This likely reflects common atmospheric contributing sources to the study area.

Air Pollutants↗