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Biomedical subjects

J D Walter

Publications and source records attributed to J D Walter.

At least 37 records · Page 2Linked to original sources
PubMed1995

A study of partial denture designs produced by an alumni group of dentists in health service practice.

Seventy-three dental surgeons working in general dental practice, all members of an alumni group, were given identical casts and produced designs for a mandibular partial denture. The designs were subsequently analysed and the dentists' skills in communicating their design intentions to technicians were also assessed. In this instance a preference for simple straightforward designs was demonstrated with a tendency to favour stereotype responses to detailed design challenges, which were not necessarily apposite. More recent graduates produced designs which were more likely to be understood by the technician.

Communication↗
PubMed1994

A scanning electronmicroscopy investigation of the structure of colonies of different morphologies produced by phenotypic switching of Candida albicans.

Variant colony formation by Candida albicans has been described and the phenomenon of phenotypic switching has been studied extensively. Whereas the microstructure of non-variant colonies has been investigated by scanning electronmicroscopy (SEM), the relationship between switched variant colonies and microstructure has not been described. The object of this study was to investigate and compared by SEM the microstructure of the normal colony type and five common variant colony types of C. albicans and to determine whether a pattern of dimorphic growth could account for the characteristic colony morphologies. A general relationship between colony type and structure was observed; smooth colonies consisted entirely of blastospores whereas regular, irregular-wrinkled and semi-rough colonies consisted of different proportion of true hyphae and blastospores. Regular extreme-jagged shaped colonies consisted of an almost pure culture of pseudohyphae, and colonies producing aerial hyphae were composed of pseudo- and true hyphae, as well as blastospores. These results show a clear relationship between colony morphology and development of particular cell types.

Candida albicans↗
PubMed1993

Accuracy of fit of cobalt-chromium removable partial denture frameworks on master casts.

Fifty-six cobalt-chromium removable partial denture frameworks made to the same design were found to fit their master casts poorly. Spaces were significantly greater between palatal aspects of abutment teeth and palatal reciprocal arms, and between buccal aspects of occlusal rests and rest seats. Excessive contraction towards the centre of the palate was found. Expansion of the refractory investment may not have compensated adequately for solidification and cooling contraction of the cobalt-chromium alloy. Although dimensional changes in investment and casting are by volume, no evidence of anisotropic expansion of castings in a vertical direction was found.

Chromium Alloys↗
PubMed1993

Relationship of lactate and ventilatory thresholds in cardiac transplant patients.

The ventilatory threshold (VT) has been suggested as a method for determining exercise training intensity in cardiac transplant patients (CTPs). Since the VT has not been validated against the more accepted marker of the anaerobic threshold, the lactate threshold (LT), in CTPs, the purpose of this investigation was to compare the VT to the LT within, as well as between, CTPs and normal subjects (NLs). Ten male orthotopic CTPs and 10 age, size, and gender matched NLs were exercised to symptom-limited maximal levels following incremental treadmill protocols. The VT was determined using the V-slope method, and the LT was identified using the log-log transformation method. The NLs and significantly higher absolute levels of VO2 at both the VT (1298.6 +/- 78.5 vs 919.0 +/- 57.2 ml.min-1) and LT (1561.1 +/- 144.2 vs 921.6 +/- 47.6 ml.min-1) compared with the CTPs. However, there was no significant difference in the relative VO2 (% peak) between CTPs and NLs at the VT (57.2 +/- 3.0 vs 49.0 +/- 3.5%) or LT (58.2 +/- 3.3 vs 58.5 +/- 4.9%), respectively. Within groups there was no significant difference between the VT and LT for either CTPs (919.0 +/- 57.2 vs 921.6 +/- 47.6 ml.min-1 or NLs (1298.6 +/- 78.5 vs 1561.1 +/- 144.2 ml.min-1). From the results of this investigation it appears that the VT may be used as an indicator of LT in CTPs and is within a range acceptable for clinical application.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Palatopharyngeal activity in cleft palate subjects.

A literature review of the nature of the musculature of the cleft palate and the pharynx is provided and a rationale presented for determining the anatomic level at which muscle activity occurs. Nasal endoscopy with a rigid telescope and the placement of miniaturized pressure transducers against the pharyngeal walls were the techniques used to investigate palatopharyngeal defects in cleft palate subjects. Ten basic patterns of palatopharyngeal movement are described and the likely interplay of the various muscles in producing these complex movements is discussed. Closure patterns of the palatopharyngeal isthmus varied according to whether the subjects were speaking, sucking, or swallowing. It was concluded that the presence of an obturator in the pharynx affects the pattern of activity and that the obturator should be developed to speech function rather than to swallowing.

Cleft Palate↗
PubMed1990

Webbing of the pharyngeal recess in adults with cleft palate.

The limited literature on the lateral pharyngeal recess of Rosenmüller and the various presentations of pharyngeal webbing are reviewed. Webbing across the lateral pharyngeal recess is described in 28 of 31 adults with cleft palate examined. The phenomenon has not been reported before and does not appear to be a feature of the nasopharyngeal wall in noncleft individuals.

Aged↗
PubMed1987

A study of the long term results achieved by the Gillies Fry procedure.

Renewed interest in delayed closure for cleft palate subjects revealed that no evaluation had been undertaken of patients who underwent the original Gillies Fry procedure. In the present investigation, 10 subjects operated upon prior to 1948 according to the Gillies Fry recommendations were evaluated for facial development, occlusal relationship, speech performance and velopharyngeal seal. Comparison of the cephalometric findings with accepted norms and examination of study casts gave encouraging results for facial and occlusal development. Speech quality covered a wide range of attainment, the best being rated highly. Endoscopic examination demonstrated regular velopharyngeal seal during swallowing but only one subject who regularly achieved velopharyngeal seal in speech. It was concluded that, although some claims for the procedure may have been a little enthusiastic, advantages accrued from it which were not accorded by other surgical approaches of the time, particularly so far as facial development and occlusion were concerned.

Adult↗