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Biomedical subjects

D M Collins

Publications and source records attributed to D M Collins.

At least 73 records · Page 4Linked to original sources
PubMed1993

DNA fingerprinting of Mycobacterium bovis strains by restriction fragment analysis and hybridization with insertion elements IS1081 and IS6110.

Strains of Mycobacterium bovis, the causative organism of bovine tuberculosis, can be clearly distinguished from each other by restriction fragment analysis. This method of DNA fingerprinting has been used for many epidemiological studies in New Zealand, but the technique presents practical difficulties that hinder its widespread use. The insertion element IS6110 is being widely used as a DNA probe for distinguishing restriction fragment polymorphisms among strains of Mycobacterium tuberculosis. Both this element and another recently sequenced element, IS1081, are also present in M. bovis. We assessed the usefulness of these two elements for distinguishing between 160 strains of M. bovis. These strains, most of which were isolated in New Zealand, were selected to be representative of the 95 different types that were identified among 530 strains that were previously typed by restriction fragment analysis. Fifteen IS6110 types were identified, but more than half of the strains representing 46 restriction types had the same IS6110 type. Virtually all M. bovis strains as well as strains of M. tuberculosis and Mycobacterium africanum had the same IS1081 type. The results indicate that for M. bovis, IS1081 cannot be used to type strains, IS6110 can be used to distinguish strains into broad groups, but only restriction fragment analysis is sufficiently sensitive for detailed epidemiological studies. An investigation of the host range of IS1081 revealed that, apart from its presence in species of the tuberculosis complex, it is also present in a strain of Mycobacterium xenopi.

Animals↗
PubMed1993

Seals, seal trainers, and mycobacterial infection.

In 1986, three seals died in a marine park in Western Australia; culture of postmortem tissue suggested infection with Mycobacterium bovis. In 1988, a seal trainer who had been employed at the Western Australian marine park until 1985 developed pulmonary tuberculosis caused by M. bovis while working in a zoo 3,000 km away on the east coast of Australia. Culture characteristics, biochemical behavior, sodium dodecyl sulphate polyacrylamide gel electrophoresis, and restriction endonuclease analysis suggested that the strains of M. bovis infecting the seals and trainer were identical but unique and differed from reference strains and local cattle strains of M. bovis. The infection in both the seals and the trainer had a destructive but indolent course. This is the first time that M. bovis has been observed in seals and the first time that tuberculous infection has been documented to be transmitted from seals to humans. Further investigation of the extent of tuberculous infection in seal populations elsewhere in the world seems warranted, and those working with seals and other marine animals should be monitored for infection.

Animals↗
PubMed1993

Paratuberculosis in farmed deer: case reports and DNA characterization of isolates of Mycobacterium paratuberculosis.

Mycobacterium paratuberculosis was isolated from farmed deer in New Zealand on 21 occasions over a 7-year period. The number of cases increased during the last 3 years of the study. Clinical paratuberculosis was observed in 5 deer, 3 other cases came from grossly normal animals that reacted to a tuberculin skin test, and the remaining 13 animals had tuberculous lesions that were identified at meat inspection. Pathologic features of the lesions in these 13 cases included necrosis and mineralization in lymph nodes draining the gastrointestinal tract. The histologic changes in these lesions were very similar to those caused by Mycobacterium bovis and members of the M. avium complex. Characterization of 20 of the isolates of M. paratuberculosis by restriction endonuclease analysis and DNA hybridization revealed that 3 of these isolates were identical to New Zealand sheep isolates and 17 were the same as cattle isolates. The source of the cervine infections was not determined.

Animals↗
PubMed1993

Apparent valproic acid neurotoxicity in a hypoalbuminemic patient.

OBJECTIVE: To report a case of possible neurotoxicity caused by markedly elevated free valproic acid (VPA) plasma concentrations. CASE SUMMARY: A patient with a history of a mixed-type seizure disorder that had been treated with oral VPA 1000 mg four times daily for the previous two years was admitted to the neurology service with the chief complaint of increasing difficulty in walking and involuntary muscle jerks that were new in onset. The patient was hypersomnolent and dysarthric. The total plasma VPA concentration was 103 micrograms/mL, which was only slightly above the recommended therapeutic range (50-100 micrograms/mL). VPA free fraction and free plasma concentrations, however, were unexpectedly elevated (26 percent, 26.8 micrograms/mL, respectively). Further laboratory evaluation revealed a serum albumin concentration of 33 g/L. The neurologic symptoms resolved upon VPA dosage reduction. DISCUSSION: VPA displays concentration-dependent protein binding, resulting in disproportionate increases in drug free fraction with increasing drug concentration. This effect may be magnified in patients with decreased plasma protein-binding capacity. The plasma protein-binding kinetics of VPA are reviewed and the implications for therapeutic drug monitoring are discussed. CONCLUSIONS: It is likely that the markedly elevated free VPA plasma concentrations contributed to the neurologic symptoms displayed in this patient. In patients with decreased albumin concentrations, failure to recognize concentration-dependent protein binding, as well as exclusive reliance upon total drug concentrations, may lead to erroneous pharmacokinetic and therapeutic interpretations.

Adult↗
PubMed1993

Potential interaction between carbamazepine and loxapine: case report and retrospective review.

OBJECTIVE: To report a potential interaction between carbamazepine (CBZ), an anticonvulsant medication, and loxapine, an antipsychotic. CBZ is being increasingly used to treat a variety of psychiatric disorders. Because of this, the potential for multiple-drug therapy and subsequent drug interactions is increased. METHODS: We prospectively monitored plasma CBZ and carbamazepine epoxide (CBZE) concentrations in a single patient during and after withdrawal of loxapine comedication. Additionally, we retrospectively evaluated four patients who had received concomitant therapy with CBZ and loxapine. RESULTS: Plasma CBZE/CBZ ratios decreased from 0.76 to 0.18 following discontinuation of loxapine. Absolute CBZE plasma concentrations also decreased from 1.7 to 0.6 micrograms/mL after loxapine therapy was stopped. Retrospectively screened patients who were receiving concomitant loxapine-CBZ therapy all had unusually elevated CBZE/CBZ plasma concentration ratios (0.75-1.91). CONCLUSIONS: These cases suggest that an interaction occurs between loxapine and CBZ. Possible mechanisms include either induction of CBZ metabolism to its epoxide metabolite, or inhibition of the enzymatic metabolism of CBZE (epoxide hydrolase).

Adult↗
PubMed1993

Tolerance of hemodialysis: a randomized prospective trial of high-flux versus conventional high-efficiency hemodialysis.

Hemodialysis is frequently complicated by hypotension and associated symptoms. It has been suggested that these symptoms may be related to the biochemical changes caused by cellulosic dialysis membranes. In this study, a prospective randomized crossover trial was conducted comparing the incidence of hypotension and acute symptoms during dialysis with large-surface-area (1.6 m2) cellulosic (cuprophane [CUP]) and noncellulosic (polyacrylonitrile [PAN], AN69) membranes. Dialyzers were used for a single use only. There was no difference in predialysis BUN, predialysis blood pressure, intradialytic weight gain, blood flow, dialysis efficiency (urea reduction), dialysis duration, hematocrit, or erythropoietin dose between the two study phases. When these clinical characteristics were matched, there was no difference in the number of episodes of hypotension (CUP, 19 +/- 3; PAN, 22 +/- 3; P = not significant [NS]). The incidence of symptomatic hypotension, as reflected by the number of episodes of hypotension requiring more than 100 mL of saline for correction, was also not different between study phases (CUP, 10 +/- 1; AN69, 11 +/- 2; P = NS). The incidence of intradialytic symptoms, including emesis, cramping, headache, angina, pruritus, and bronchospasm, was similar during the two study phases (CUP, 11 +/- 2; AN69, 10 +/- 1; P = NS). It was concluded that noncellulosic membranes do not offer any significant advantage over cellulosic membranes in reducing the acute complications of hemodialysis.

Acrylic Resins↗
PubMed1992

General practitioners' views on the role of the community pharmacist.

AIM: to determine the views of general practitioners on the roles and activities of community pharmacists. METHOD: the views of 137 general practitioners in Otago and Southland were canvassed by postal questionnaire. RESULTS: one hundred and three completed questionnaires were returned. All of the general practitioners reported that their professional contact with pharmacists was useful. Seventy-five percent expressed a desire for greater cooperation. Nearly all respondents (99%) accepted that pharmacists have a role in screening prescriptions for possible problems and preparing and dispensing medicines. They also accepted that pharmacists were capable of treating and advising in the management of minor illnesses. Providing drug information to general practitioners, information about previously diagnosed conditions to patients, and advice on personal and home hygiene were less widely accepted activities. The majority indicated that they considered it inappropriate for pharmacists to undertake screening programmes (blood pressure (70.6%), cholesterol (70.6%), glucose (60.8%), haemoglobin (72.5%)). Younger general practitioners objected more often than older general practitioners to reclassification of Acetopt eye drops from prescription only to availability through pharmacies (p < 0.05). Female general practitioners were more often in favour of reclassification of Gyno-Daktarin than their male colleagues (p < 0.05). CONCLUSION: this study shows that general practitioners accept several aspects of the current role of pharmacists in providing primary health care. However, there is room for improved communication between general practitioners and pharmacists to ensure optimum patient care.

Adult↗
PubMed1992

Fistula dysfunction: effect on rapid hemodialysis.

Rapid hemodialysis (Qb 400 to 500 ml/min) places considerable demands on hemodialysis vascular access. This six-month prospective study enrolled 52 patients and evaluated urea recirculation as a means of detecting fistula dysfunction. It evaluated the effects of fistula location and dialysis blood flow on urea recirculation during rapid hemodialysis and assessed the effect of rapid dialysis on fistula thrombosis. Urea recirculation increased as Qb increased from 300 to 400 ml/min (8 +/- 3% to 16 +/- 3%, P less than 0.05). The extent of urea recirculation was also fistula site dependent (radial fistulas 18 +/- 4%, upper arm fistulas 11 +/- 3%, Qb 400 ml/min, P less than 0.05). Site and blood flow dependent urea recirculations were an indicator of venous stenoses. When venous stenoses were corrected, urea recirculation rates improved (36 +/- 3% to 21 +/- 3%, P less than 0.05). There were no differences between methods of determining urea recirculation early in dialysis (contralateral arm venepuncture vs. stop flow technique; 30 to 60 min). However, at 120 minutes urea recirculation was significantly greater with the contralateral arm venepuncture technique. Venous dialysis pressure at Qb 400 ml/min had limited use as a predictor of venous stenoses unlike its value at lower Qb. Fistula thrombosis (0.26/patient year of dialysis) and fistula replacement (0.09/patient year of dialysis) were similar to our observations in a conventional hemodialysis facility where prospective correction of fistula dysfunction was also used.

Arteriovenous Shunt, Surgical↗
PubMed1991

Identification of an insertion sequence, IS1081, in Mycobacterium bovis.

An insertion sequence, IS1081, in the genome of Mycobacterium bovis has been identified and sequenced. It is 1324 bp long with 15 bp inverted repeat ends and contains a large ORF. There are six copies of IS1081 in the genome of M. bovis and the element is also present in Mycobacterium tuberculosis. IS1081 is not closely related to other DNA elements described in actinomycetes but its putative transposase bears some resemblance to that of IS256 from Staphylococcus aureus. IS1081 may be useful for genetic manipulations and for developing a diagnostic test for bovine tuberculosis based on the polymerase chain reaction.

Base Sequence↗
PubMed1990

A report of tuberculosis in cats in New Zealand, and the examination of strains of Mycobacterium bovis by DNA restriction endonuclease analysis.

Mycobacterium bovis was isolated from diagnostic samples from 57 cats submitted to New Zealand Animal Health Laboratories from 1974 to 1986. With six exceptions, these cats came from suburban and rural areas of New Zealand where M.bovis was also present in feral and wild animals, especially the brush-tailed possum. Tuberculous skin lesions were seen in 33 (58%) of the cats. Histologically, these lesions had some similarities to those of cat leprosy. Included in the 57 cats was a group of 12 tuberculous animals which were diagnosed in a suburban veterinary practice over a 3 month period. When these 12 M. bovis isolates were examined by DNA restriction endonuclease analysis, they were found to be identical. This evidence, together with the relatively short period during which the cases occurred, suggested that these cats were exposed to a single source of infection.

Journal Article↗
PubMed1990

Prevotella, a new genus to include Bacteroides melaninogenicus and related species formerly classified in the genus Bacteroides.

It was recently proposed that the genus Bacteroides should be restricted to Bacteroides fragilis (the type species) and closely related organisms (viz., B. caccae, B. distasonis, B. eggerthii, B. merdae, B. ovatus, B. stercoris, B. thetaiotaomicron, B. uniformis, and B. vulgatus). By contrast, the moderately saccharolytic, predominantly oral Bacteroides species, which include B. melaninogenicus, B. oralis, and related species, form a phenotypically and phylogenetically coherent group of species which differ so significantly from the emended description of the genus Bacteroides that they should not be classified in the same genus. Therefore, we formally propose that these species be reclassified in a new genus, Prevotella. The type species is Prevotella melaninogenica.

Bacteria↗
PubMed1990

Identification of two groups of Mycobacterium paratuberculosis strains by restriction endonuclease analysis and DNA hybridization.

Genomic DNA was prepared from four reference strains of Mycobacterium paratuberculosis and 46 isolates of this organism from New Zealand, Australia, Canada, and Norway and also from two mycobactin-dependent "wood pigeon" strains. The DNA was characterized by restriction endonuclease analysis, both with and without DNA hybridization, with a probe specific to a repetitive DNA sequence in M. paratuberculosis. Both techniques differentiated M. paratuberculosis strains into two groups, but DNA hybridization revealed more differences between strains within the larger group. All the strains from cattle and many strains from other animals belonged to this group. The second group of nine strains included the Faroe Islands strain, all New Zealand sheep strains, and one New Zealand goat strain. Primary isolation of strains belonging to this group was difficult to achieve. DNA from acid-fast organisms harvested directly from intestinal tissues of sheep with Johne's disease was shown to have restriction and hybridization patterns identical to those of DNA obtained from M. paratuberculosis isolates cultured from the same tissues. Two Norwegian goat strains and the wood pigeon strains did not hybridize to the M. paratuberculosis probe and had restriction patterns very different from those of other M. paratuberculosis strains. The wood pigeon strains had restriction patterns very similar to those of strains of Mycobacterium avium, indicating that they should be classified as that species. The presence of two distinct groups of M. paratuberculosis strains and their predominant distribution in different host animals may be significant in management of mixed-animal farming operations.

Animals↗
PubMed1990

Tuberculosis in captive seals: bacteriological studies on an isolate belonging to the Mycobacterium tuberculosis complex.

Culture of tuberculous lesions from six of 14 captive seals yielded an organism which, on the basis of biochemical and drug sensitivity tests, was identified as Mycobacterium bovis, although the organism showed a weak cording pattern and was glycerol tolerant. It was pathogenic in rabbits and guinea pigs and after passage the organism exhibited strong cord formation and was glycerol intolerant. Restriction endonuclease analysis and sodium dodecyl-sulphate polyacrylamide gel electrophoresis indicated that the organism belonged to the Mycobacterium tuberculosis complex. Restriction patterns indicated that infection in the six seals was from a single source. Western blotting with monoclonal antibody to M bovis identified antigens at 23 and 27 kDa in M bovis which were absent from the seal isolates.

Animals↗
PubMed1989

Identification of a repetitive DNA sequence specific to Mycobacterium paratuberculosis.

A 0.2-kb DNA sequence specific to Mycobacterium paratuberculosis, the causative organism of Johne's disease, was isolated from a partial genomic library. The sequence was part of a larger repetitive DNA element and was present in strains of M. paratuberculosis from cattle, sheep, goat, deer and also a woman with Crohn's disease but not in M. paratuberculosis strain 18. The sequence was not present in strains of 19 other mycobacterial species including 31 reference serotype strains of the M. avium-M. intracellular-M. scrofulaceum (MAIS) complex, some strains of which are closely related to M. paratuberculosis. The sequence may be useful for developing a diagnostic test for Johne's disease.

Animals↗
PubMed1989

Distribution of fatty acid binding proteins in tissues and plasma of Gallus domesticus.

1. Fatty acid binding activity associated with a 14,000-15,000 mol. wt protein was observed in the cytosolic fraction of liver, duodenum, myocardium, adipose, pectoral and gastrocnemius muscles of chickens. 2. Polyclonal antisera prepared against chicken liver fatty acid binding protein affinity for only liver FABP and a 14,000 mol. wt fatty acid binding protein in the intestine. 3. A fatty acid binding protein was not detected in chicken plasma.

Animals↗
PubMed1989

High-protein feeding stimulates renal thromboxane production in rats with streptozocin-induced diabetes.

In diabetic rats glomerular morphologic damage is exacerbated by feeding a protein-rich diet. Protein feeding alters arachidonic acid metabolism in other models of renal disease, and there is evidence that the arachidonic acid metabolite thromboxane plays a pathophysiologic role in protein-induced renal injury. In this study we evaluated the effect of high-protein feeding on renal thromboxane production, renal hemodynamics, and renal morphologic condition in rats with experimentally induced diabetes. We induced diabetes in male Sprague-Dawley rats by streptozocin administration. Rats then received high (60% casein)- or low (8% casein)-protein diets. Eight to 11 weeks later, clearance of inulin and PAH and renal blood flow were measured. Rats fed 60% casein had higher glomerular filtration rate and renal blood flow than rats fed low-protein diets. Rats fed high-protein diets had more glomerular hypercellularity, tubular hypertrophy, and arteriolar thickening than their protein-restricted counterparts. Renal production of 6-keto-PGF1a and PGE2 was not different between dietary groups. Renal thromboxane production, however, was greater in rats fed 60% protein than in rats fed 8% protein. We conclude that protein feeding stimulates renal thromboxane production and exacerbates morphologic injury in the diabetic rat. Short-term administration of the thromboxane synthetase-inhibitor UK 38,485 did not further increase glomerular filtration rate or renal blood flow in animals fed high protein. Thus thromboxane did not appear to play a role in protein-induced injury in this model by a vasoconstrictive mechanism. Other possible mechanisms by which thromboxane may contribute to the renal damage observed are discussed.

Animals↗