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J D Buck

Publications and source records attributed to J D Buck.

31 records · Page 2Linked to original sources
PubMed1980

A reemphasis-Germ tubes diagnostic for Candida albicans have no constrictions.

Descriptive and illustrative material in several recent diagnostic manuals for medical mycology are unclear with respect to proper designation of germ tubes formed by Candida albicans. Because of the increasing significance of this and other yeast species in human disease, mycologists should be aware that germ tubes, unlike buds or pseudohyphae, do not have constrictions at the point of origin. Light and scanning electron micrographs are presented to emphasize this diagnostic characteristic.

Candida albicans↗
PubMed1980

Occurrence of human-associated yeasts in the feces and pool waters of captive bottlenosed dolphins (Tursiops truncatus).

Total yeast counts at 20 and 37 C incubation from chlorinated salt water pools containing marine mammals averaged 40 per L and 12 per L, respectively. Candida albicans, the etiological agent of candidiasis in mammals, was found in 32% of 123 water samples although numbers were low (average of 1.2 cells per L). The yeast was isolated only once from feces from one Atlantic bottlenosed dolphin (Tursiops truncatus) but was recovered from three fecal samples from an asymptomatic beluga whale (Delphinapteras leucas) which suggested that this animal may be a carrier. Three yeasts (Candida tropicalis, C. parapsilosis, and Torulopsis glabrata) associated with human disease accounted for 73% and 88%, respectively, of the 37 C isolates from water and animals. The data indicate the routine presence of potentially pathogenic yeasts in water and various marine mammals. Captive environments characterized by antimicrobial treatment (e.g., chlorine) may provide appropriate conditions for resistant microorganisms, including yeasts, to become opportunistic pathogens in susceptible marine mammals or to become established in others which act as healthy carriers.

Animals↗
PubMed1978

Membrane filter procedure for enumeration of Candida albicans in natural waters.

A membrane filter procedure is described for the enumeration of Candida albicans in natural waters. Several hundred milliliters of sample can be examined by filtration through 1.2-micrometer membranes. Selectivity is achieved by the use of a defined (yeast-nitrogen base plus maltos-) agar medium inclusion of the antimicrobial agents chloramphenicol and cycloheximide, and incubation at 37 degrees C. C. albicans colonies are differentiated primarily through color by use of a bismuth salt indicator system. Average recovery of various strains of C. albicans stressed in seawater at 4 degrees C was 82%, compared with those of spread plate controls on a noninhibitory medium. With river water and raw sewage, 90% of typical C. albicans colonies were confirmed as such in a simplified germ tube test. Atypical colonies verified as C. albicans were infrequent (3%). C. tropicalis and Torulopsis candida were the most common false-positive colonies.

Candida albicans↗
PubMed1977

Occurrence of human-associated yeasts in bivalve shellfish from Long Island Sound.

Candida parapsilosis, C. tropicalis, and Torulopsis glabrata were the human-associated yeasts most frequently isolated from quahogs, oysters, and mussels collected from four estuarine areas along the northern shore of Long Island Sound. Some inconsistency and seasonal variation in the occurrence of these and other yeast species were noted. In particular, C. albicans densities were greatest during colder months in the more heavily polluted waters. A total of 347 yeasts were isolated and cultured at 37 degrees C and, of these, 219 of 62% were human-associated forms. Generally, these yeasts in the animals sampled reflected the overall pollution status of the estuary from which they were taken. This study represents a clear demonstration of potentially pathogenic yeasts in a valuable marine resource.

Animals↗
PubMed1969

Occurrence of false-positive most probable number tests for fecal streptococci in marine waters.

By the use of the most probable number technique with azide dextrose and ethyl violet azide broths for enterococci, the common occurrence of false-positive tests was noted when marine and estuarine waters were sampled. Organisms isolated included a marine bacterium, gram-positive and gram-negative nonmarine bacteria, and yeasts. All cultures were capable of growth in azide-dextrose, ethyl violet-azide, and KF broths. Representative isolates grew in media containing 0.08% NaN(3). The tentatively accepted most probable number method for fecal streptococci is thus of dubious value in assessment of sewage pollution levels in estuarine waters. All positive tubes must be examined microscopically for the presence of nonstreptococcal forms.

Bacteriological Techniques↗
PubMedDate not supplied

Beneficial actions of bevantolol on subendocardial blood flow and contractile function in ischemic myocardium.

The effect of a new cardioselective beta adrenergic antagonist, bevantolol (CI-775), on regional myocardial blood flow and contractile function distal to a severe flow-limiting stenosis of the left circumflex coronary artery was studied in open-chest dogs. Bevantolol (1 mg/kg, i.v.) or saline was administered 30 min after production of left circumflex stenosis sufficient to reduce resting coronary blood flow and contractile force approximately 40%. Regional myocardial blood flow and contractile force were measured with radiolabeled microspheres and Brodie-Walton strain gauge arches, respectively. No significant changes were observed in the saline-treated group. Following bevantolol treatment subendocardial blood flow (1.30 +/- 0.29 to 0.93 +/- 0.19 ml/min/g) and contractile force decreased (11.4 +/- 4.4%) significantly (p less than 0.05) in nonischemic myocardium. Subendocardial blood flow (0.59 +/- 0.14 to 0.81 +/- 0.14 ml/min/g) and contractile force increased (29.3 +/- 3.6%) significantly (p less than 0.05) in ischemic myocardium. These results suggest that bevantolol produces a favorable redistribution of flow to ischemic subendocardium. The increase in flow results in an improvement of contractile function in the ischemic region.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Separation of overlap and collateral perfusion of ischemic canine myocardium: important considerations in the analysis of vasodilator-induced coronary steal.

Coronary steal was studied in dogs with a left anterior descending (LAD) coronary artery occlusion by use of a special technique to exclude contamination from overlapping circulations with true collateral blood flow. Different degrees of vasodilation in nonischemic myocardium were produced by the selective coronary dilator, chromonar, at a constant heart rate and aortic blood pressure. A map of the ischemic area was made, and criteria used to identify ischemic tissue samples included: (1) all samples within the LAD perfusion area, as defined by a dye technique; (2) tissue samples with blood flows less than 25% normal area flow; (3) samples from within the central ischemic zone; and (4) tissue samples with overlap blood flow less than 2% normal area flow. When criteria 1 and 2 were used to identify ischemic myocardium, chromonar (5 and 7.5 mg/kg, i.v.) produced no change in ischemic blood flow. On the other hand, when tissue samples from the central ischemic zone or those which had less than 2% overlap flow (criteria 3 and 4) were used to identify ischemic myocardium, chromonar produced a dose-related decrease (p less than 0.01) in transmural collateral perfusion (25 +/- 4 and 33 +/- +/- 5;33 +/- 3 and 41 +/- 6%, respectively). Other indices of collateral function, peripheral coronary pressure (23 +/- 4 and 25 +/- 3%), retrograde flow (20 +/- 3 and 26 +/- 4%), and retrograde conductance (21 +/- 4 and 30 +/- 4%), also decreased significantly. These results indicate that moderate to maximal coronary vasodilation produces a true coronary steal in the absence of changes in aortic pressure and heart rate. In addition, these data demonstrate that significant amounts of overlap flow are contained in superior, inferior, and lateral borders of the ischemic zone, and that strict criteria to identify ischemic myocardium are needed when studying the effect of drugs on true coronary collateral blood flow.

Animals↗