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Biomedical subjects

R Bond

Publications and source records attributed to R Bond.

71 records · Page 4Linked to original sources

Population sizes and frequency of Malassezia pachydermatis at skin and mucosal sites on healthy dogs.

Skin and mucosal carriage of Malassezia pachydermatis was studied in 20 healthy pet dogs of various breeds and in 20 kennelled beagles. Using swabs, anal carriage was detected in 10 pet dogs and 11 beagles and the nose, mouth, prepuce and vulva were shown to be infrequently colonised. M pachydermatis was isolated from the external ear canal of 11 beagles and two pet dogs; both the population sizes and frequency of isolation were significantly (P < 0.05) greater in the beagles. The yeast was infrequently isolated from the axilla and groin in low numbers using contact plates and detergent scrub samples but was often cultured from the lower lip and the dorsal interdigital spaces; isolation frequencies and population sizes in the two groups of dogs were not significantly different. These results demonstrate that the anus, external ear canal and lip and interdigital skin of healthy dogs are frequently colonised by M pachydermatis.

Animals↗

Evaluation of two enzyme-linked immunosorbent assays for the diagnosis of canine atopy.

Serum samples from 10 dogs without skin disease, 10 with non-atopic pruritic skin disease, and 10 atopic dogs were tested blind by using two enzyme-linked immunosorbent assays (ELISAS) (Veterinary Allergy Test Kit; All-Vet [test A] and Elisarest; Bloxham Laboratories [test B]) designed to detect immunoglobulin E antibodies to environmental allergens. All the dogs tested had at least three positive reactions when using test A, and 28 of the dogs had at least one positive reaction when using test B. The median numbers of positive reactions observed in the three groups of dogs were not significantly different for each test. Significantly more reactions were observed with test A in each group (P < 0.001) than with test B. The sensitivity of both the tests was 100 per cent, but the specificity of test A was 0 per cent and the specificity of test B was 10 per cent. The positive predictive values of tests A and B were 33.3 per cent and 35.7 per cent, respectively, and the negative predictive values were 0 and 100 per cent. The poor specificities and low positive predictive values indicate that the positive results obtained when using these ELISAS are of no diagnostic value in canine atopy.

Allergens↗

Combined treatment with concentrated essential fatty acids and prednisolone in the management of canine atopy.

Eleven perennially affected atopic dogs which had previously responded poorly to dietary supplementation with a combination of evening primrose oil and fish oil were studied to determine whether a concentrated essential fatty acid supplement containing gammalinolenic acid and eicosapentaenoic acid would reduce their prednisolone requirements. The prednisolone dose required for satisfactory control of the dogs' clinical signs was reduced in eight of the 11 cases when assessed after 12 weeks of supplementation, but there were no significant differences in mean clinical scores during the same period. The mean plasma phospholipid linoleic acid concentrations after eight and 12 weeks of supplementation were significantly lower than the initial mean value but there were no significant differences in the mean plasma phospholipid concentrations of dihomogammalinolenic acid, arachidonic acid and eicosapentaenoic acid.

Administration, Oral↗

The sydnonimine C87-3754 evokes endothelium-independent relaxations and prevents endothelium-dependent contractions in blood vessels of the dog.

Experiments were designed to compare the relaxing activities of the new sydnonimine C87-3754 with SIN-1 in arteries and veins of the dog, and to determine whether C87-3754 can prevent endothelium-dependent contractions. Rings of coronary and femoral arteries, and saphenous veins were suspended in organ chambers for the measurement of changes in isometric tension. SIN-1 and C87-3754 evoked concentration-dependent relaxations in all rings of blood vessels contracted with a submaximal concentration of either prostaglandin F2 alpha, endothelin-1, phenylephrine, or norepinephrine. In both arteries and veins, the concentration-relaxation curves to C87-3754 were shifted significantly to the right (by two to three logarithmic units) of that to SIN-1. The presence of endothelium significantly inhibited the relaxations to SIN-1 but did not affect those to C87-3754. The treatment of coronary arteries with methylene blue or oxyhemoglobin significantly impaired the relaxation to SIN-1 and C87-3754. Neither C87-3754 nor its prodrug pirsidomine (CAS 936) affected the membrane potential in coronary arteries. The endothelium-dependent contractions evoked by nitro L-arginine, arachidonic acid, and the calcium ionophore A23187 in basilar arteries of the dog were inhibited by C87-3754. These results indicate that the sydnonimine C87-3754 is a dilator of both arterial and venous smooth muscle, and can prevent endothelium-mediated contractions in cerebral arteries of the dog. The inhibition of vascular tone is likely to involve the activation of soluble guanylate cyclase, causing enhanced production of cyclic guanosine monophosphate in the smooth muscle without a change in membrane potential.

Animals↗

A double-blind comparison of olive oil and a combination of evening primrose oil and fish oil in the management of canine atopy.

A randomised double-blind parallel study lasting eight weeks was used to assess the effects of olive oil in a group of atopic dogs whose clinical signs were well controlled by dietary supplementation with a combination of evening primrose oil and fish oil. Nine of the 11 dogs which continued to receive this combination were considered unchanged at the conclusion of the study, whereas eight of the 10 dogs switched to olive oil had deteriorated. The mean plasma concentration of dihomogammalinolenic acid, a precursor of potentially antiinflammatory mediators, was significantly reduced (P < 0.05) in the olive oil-treated group at the end of the study. There were no significant differences between the mean plasma linoleic, eicosapentaenoic and arachidonic acid concentrations in the two groups. These findings suggest that olive oil is not an effective therapeutic agent in the control of canine atopy.

Animal Feed↗

Serial serum drug concentrations and prolonged anticholinergic toxicity after benztropine (Cogentin) overdose.

A 38-year-old man overdosed on benztropine mesylate (Cogentin; Merck Sharpe & Dohme, West Point, PA) and developed anticholinergic poisoning syndrome, which lasted nine days. Serial serum benztropine concentrations were obtained during his hospitalization. Fluctuating benztropine levels suggested that his lengthy intoxication may have been secondary to prolonged, intermittent absorption rather than from slow plasma clearance. This is believed to be the first report of serial serum benztropine concentrations after overdose.

Adult↗

Monoclonal antibodies specific for ganglion cells in the embryonic chicken neural retina.

Monoclonal antibodies have been produced which recognize antigens on the surface of embryonic chicken neural retina cells. Two monoclonal antibodies, obtained from separate fusions, have been shown by fluorescence-activated cell-sorter analysis to bind to antigens on a subpopulation of neural retina cells. Immunohistochemical methods demonstrate that both monoclonal antibodies bind to the nerve fiber and inner plexiform layers of the embryonic neural retina. These monoclonal antibodies also bind to cell bodies and neurites of cultured retinal neurons and therefore selectively recognize antigens localized to the surface ganglion cells. One of the monoclonal antibodies binds to a 260 kdalton polypeptide, which has been shown to be developmentally regulated by immunoblotting and immunocytochemistry, as it is not detected in late embryonic neural retina. The second monoclonal antibody appears to bind to different antigens in neural and non-neural tissue. In liver extracts the monoclonal antibody recognizes a trypsin-sensitive antigen, but the antibody reacts with trypsin-resistant molecules in neural tissue. This monoclonal antibody may therefore bind a glycolipid component in the neural retina, although this remains to be determined. These antibodies can be used to obtain cell populations highly enriched in retinal ganglion cells.

Animals↗

Platelet collection using the IBM 2997 cell separator.

Platelets were collected using the dual-channel module on the IBM 2997 Blood Fraction Separator. We carried out 320 procedures to harvest platelets for therapeutic purposes and yielded 5.1 +/- 1.5 X 10(11) platelets (mean +/- SD). Infusion into previously unsensitized recipients with hypomegakaryocytic thrombocytopenia achieved increments at 1 hr of 19 +/- 7.3 X 10(9)/liter/m2 (mean +/- SD) and at 24 hr of 15 +/- 6.3 X 10(9)/liter/m2. The only consistent donor reaction was mild hypocalcaemia, easily corrected by calcium gluconate infusion. Changes in donor packed-cell volume and white cell count were not statistically altered (p greater than 0.05) but donor platelet counts fell from 216 +/- 43.1 X 10(9)/liter to 162.5 +2- 41.7 X 10(9)/liter (mean +/- SD) (p less than 0.01). Additional plateletphereses were carried out in seven normal volunteers, using the same technique, in order that the function of the harvested platelets could be studied. Following radiochromium labelling and reinfusion into the same donors, normal in vivo recoveries were obtained at 10 min (59.4 +/- 3.4%; mean +/- SD) and platelet mean life span was also normal (218 +/- 12 hr; mean +/- SD). Furthermore, in vitro platelet factor III availability and aggregation patterns of the harvested platelets did not differ from control values and their ultrastructural appearance was normal.

Blood Platelets↗

Comparison of filtration to continuous-flow centrifugation for plasma exchange.

The Asahi Plasmaflo Hollow Nylon Fibre Filtration System (n = 13) was directly compared to the NCI-IBM 2990 Continuous-Flow Blood Fraction Separator (n = 10) for plasma exchange. The systems were equally efficient in achieving plasma separation. There were significant differences favouring filtration for clearance of fibrinogen (P less than 0.05), and the fourth component of complement (P less than 0.01). Greater loss of urea (P less than 0.05) was found after plasma exchange, using the cell separator. The flow characteristics were markedly different. In a standardised 4-L plasma exchange, filtration took place at 35 ml/minute, with a procedure time of 109 +/- 45 minutes in contrast to centrifugation at a plasma flow collection rate of 19 ml/minute, requiring 208 +/- 17 minutes. This time advantage for the former procedure was offset by 195 minutes required to regenerate the hollow nylon fibre unit and a further 90 minutes required for cleaning under strictly controlled aseptic techniques prior to reuse. Each filter was regenerated at least twice and reused without infection, but there was incremental loss of filtration efficiency demonstrated by decreasing clearance of an intravascular marker dye. In two of the 13 procedures using the Plasmaflo system, serious reactions necessitated termination of the procedure; this did not occur using the cell separator. Restriction of the number of times that the filter unit could be regenerated without loss of efficiency, the prolonged time required for regeneration and cleaning, coupled with the need for artificial vascular access to meet high blood flow rates required, limit the usefulness of this technique for plasma exchange.

Blood Chemical Analysis↗

Limitation of the atrial extrastimulus technique for assessment of the His-Purkinje system in patients with right bundle branch block.

A prospective study of the usefulness of the atrial extrastimulus technique for assessment of the His-Purkinje system was undertaken in 19 consecutive patients with complete RBBB and an abnormal or indeterminate frontal QRS axis. A total of 59 basic cycle lengths (BCLs) could be analyzed in detail. The most common patterns of His-Purkinje conduction seen were simple linear (V1V2 vs H1H2, N = 49) or flat (H2V2 vs H1H2, N = 44) curves. This finding is related to the limitation imposed by interposition of the slowly conducting AV node between the site of the extrastimulus and the His-Purkinje system. One or more refractory periods could be measured in only 27% of BCLs (10 Effective Refractory Periods of the remaining intact His-Purkinje system plus 16 Functional Refractory Periods and 19 Relative Refractory Periods). No refractory periods of the His-Purkinje system could be determined in 8 of 19 patients (42%), the major limitation being slowed AV node conduction. The results suggest limited likelihood that additional clinically useful information about His-Purkinje system conduction can be obtained by the atrial extrastimulus technique, as used in this study, although it may be helpful in assessing other parts of the conduction system.

Adult↗

Coronary angiography and bypass surgery in Manitoba and the United States: a first comparison.

OBJECTIVE: To compare the appropriateness of use of coronary angiography (CA) and bypass surgery (CABS) in the early 1980s in one Canadian hospital and several American hospitals using explicit case-based criteria. Procedure rates were much lower in Canada during this period. SUBJECTS: Canadian subjects, 502 Manitoba residents undergoing CA at one hospital in 1981-82 were tracked forward to determine whether and when they underwent CABS. CA comparisons were made with 351 Canadian patients aged 55 years or older; 1677 American CA patients aged 65 years or older and were drawn in 1981 from three hospitals. Two hundred and forty-five patients undergoing CABS within 12 months of CA made up the Canadian sample. American CABS patients were sampled from three hospitals during 1979-82. Manitoba patients assigned to medical treatment after CA were also appraised. METHODS: Criteria were derived by an American panel of clinicians following a Delphi process; indications were rated appropriate, equivocal and inappropriate. A trained abstractor reviewed charts and assigned ratings. Results of exercise electrocardiograms were not available in the Manitoba data set, hence sensitivity analyses were performed to determine how differing proportions of positive exercise electrocardiograms might affect the Manitoba results. RESULTS: Even assuming only 50% of treadmill tests were positive in the Manitoba sample, the proportion of inappropriate CA was lower in Manitoba than for the American hospitals: 9% versus 15 to 18%. For CABS, only one of the three comparison American hospitals approached the Manitoba hospital level of appropriateness. CONCLUSIONS: In the early 1980s, there was more appropriate use of CA and CABS in a Manitoba hospital compared with several American hospitals. Many Canadian patients undergoing CA and treated medically met American indications for appropriate use of CABS. Whether this represents underprovision of necessary care remains uncertain.

Aged↗

Isolation of Malassezia sympodialis from feline skin.

Carriage of Malassezia yeasts was investigated in 17 cats in two colonies using a lipid-supplemented culture medium. Malassezia pachydermatis was isolated from one cat. Lipid-dependent Malassezia yeasts with electrophoretic karyotypes consistent with M. sympodialis were isolated from all six cats in one group and from one of 11 in the second group. To our knowledge, this is the first report of the isolation of lipid-dependent yeasts from cats.

Animals↗