PubMed Health⌕ Search

Biomedical subjects

D A Luke

Publications and source records attributed to D A Luke.

At least 19 recordsLinked to original sources
PubMed1995

Aortic arch dissection from patent ductus arteriosus.

An unusual case of aortic arch dissection from a patent ductus arteriosus (PDA) is described. An adult man had been diagnosed as suffering from pectus excavatum and PDA 10 years before. At that time the pectus was repaired, but he failed to return for surgery on the PDA and the sub-sternal strut for pectus repair was also never removed. Recently he was admitted in a peripheral hospital with chest infection. Patent ductus arteriosus murmur was audible on clinical examination. The chest X-ray showed a widened mediastinum and the pectus strut. On further investigations dissection of the aortic arch was discovered and arch replacement performed.

Adult↗
PubMed1994

Imaging of bronchial carcinoid tumours with indium-111 pentetreotide.

Neuroendocrine tumours are characterised by the expression of high affinity binding sites for somatostatin. The detection of bronchial carcinoid tumours through scintigraphic imaging is described in two patients using the novel radiolabelled somatostatin analogue indium-111 pentetreotide.

Bronchial Neoplasms↗
PubMed1993

Charting the process of change: a primer on survival analysis.

Survival analysis is a powerful and useful technique for understanding qualitative change. This article provides a practical, nontechnical introduction to the use of survival analysis for social scientists. Important issues in using survival analysis are discussed, including research design, data preparation and management, and data analysis. Attendance data from a self-help organization are used to illustrate common survival analysis tasks such as describing the overall survival and hazard functions, examining covariate effects, and modeling the form of the hazard function over time. An appendix that discusses the strengths and weaknesses of current survival analysis computer programs is included.

Data Collection↗
PubMed1992

The structure and functions of the dentogingival junction and periodontal ligament.

The dentogingival junction and periodontal ligament perform unique functions. The former makes a seal where a tooth punctures the integument; the latter, nominally a ligament, cushions the tooth during mastication, while sheltering the delicate cells which remodel the bony socket. A special feature of both tissues is the rapid turnover of their major components.

Bite Force↗
PubMed1992

Operation for cavitating invasive pulmonary aspergillosis in immunocompromised patients.

Invasive pulmonary aspergillosis is a specific form of pulmonary Aspergillus infection that occurs almost exclusively in immunocompromised patients. It differs both histologically and in its clinical course from classic aspergillomas. During a 5-year period (1986-1990), 8 patients underwent resection for cavitating invasive pulmonary aspergillosis that developed as a consequence of neutropenia during chemotherapy for malignancy. There were no perioperative deaths and no complications. This contrasts with reports of operation for classic aspergillomas. Histologic examination of the resected specimens showed that cavitating invasive pulmonary aspergillosis differed from classic aspergillomas. They consisted of necrotic lung tissue invaded by fungus with separation from the surrounding lung so that the sequestrum had the appearance of a fungus ball. Pulmonary aspergillosis is a common complication of profound neutropenia. The first hemoptysis in this group of patients is often life-threatening. The excellent results of operation in our series of patients may be attributed to their young age, good pulmonary function, and limited operation. This has lead us to recommend early surgical intervention in invasive aspergillosis once cavitation develops.

Adolescent↗
PubMed1991

Charting uncharted terrain: a behavioral observation system for mutual help groups.

Describes the development of a behavioral observation system for mutual help meetings and presents evidence supporting its reliability, validity, and utility. The MHOS-BIC (Mutual Help Observation System-Behavioral Interaction Codes) was used by 10 observers to record the sequential flow of group interaction in 527 meetings. Psychometric analyses indicate that the system performed consistently with measurement objectives. Mean kappas for each of the 12 coding categories ranged from .62 to .87; the system demonstrated sensitivity to setting and time differences; and a predictable pattern of correlations was found among BIC categories and conceptually related participant and observer ratings. Studies using the BIC to address substantive questions about mutual help are reviewed, providing further evidence for its validity and utility. An empirical description of mutual help is presented using BIC data, and the promises and limitations of the system are discussed.

Affective Symptoms↗
PubMed1991

Setting phenotypes in a mutual help organization: expanding behavior setting theory.

Expands Barker's theory of behavior settings by proposing an additional method of classifying settings based on their functional/behavioral aspects--the setting phenotype. Although behavior setting theory has been widely hailed as a revolutionary contribution to behavioral science, it has had limited impact on general psychology. This may be due in part to a reliance on a purely structural method of classifying behavior settings--the setting genotype. Behavioral data were collected from 510 meetings of 13 self-help groups from a mutual help organization for persons with problems in living. A cluster analysis was performed to uncover meaningful behavioral patterns among the groups. Four phenotypes were identified: personal, impersonal, small talk, and advising. Mutual help group phenotype was found to be related to a set of setting characteristics as well as to overall rated change of group members. The results are discussed in light of the significance of the phenotype construct for making behavior setting theory more relevant for social scientists.

Activities of Daily Living↗
PubMed1991

Prophylactic minitracheotomy in lung resections. A randomized controlled study.

Thirty consecutive patients undergoing lung resections were randomized into two groups: Group A (n = 15) received minitracheotomy postoperatively and group B (n = 15) were control patients. Postoperative respiratory course was monitored by serial clinical assessments, chest x-ray examination, arterial blood gases, sputa bacterial cultures, and the patient's requirement and response to chest physiotherpy. The two groups were similarly matched in age (mean 58.5 years), smoking habits, pulmonary functions, and surgical procedures. Postoperative pulmonary complications of collapse/consolidation developed in 11 patients (two in group A and nine in group B) (p less than 0.03). Four patients (all in group B) required nimitracheotomy in addition to antibiotics and chest physiotherapy to treat their pneumonia. Chest physiotherapy requirement was less in group A than in group B, with a mean number of sessions of seven in group A and eight in group B and a mean total time of 92 minutes in group A and 112 minutes in group B. The mean duration of minitracheotomy was 4.13 days. Minor temporary symptoms resulted from the minitracheotomy in eight patients (42%) and included discomfort, voice changes, subcutaneous emphysema, and stridor. There was one case of long-term morbidity (5%)-skin scarring from wound infection at the site of the minitracheotomy. No postoperative deaths resulted. We conclude that the prophylactic use of minitracheotomy is safe and effective in decreasing postoperative respiratory complications in patients undergoing lung resections.

Adult↗
PubMed1990

Effects of 5-fluoro-2'-deoxyuridine on cell proliferation in the developing mouse palate.

Cell proliferation following the administration of 5-fluoro-2'-deoxyuridine (FUdR) to pregnant mice was studied in the vertical palatal processes of fetuses using 3H-thymidine and autoradiography. Doses of 30 and 80 mg FUdR per kilogram maternal body weight substantially reduced the number of labelled nuclei in the epithelium and mesenchyme. Both doses of FUdR also decreased the mean number of silver grains over mesenchymal nuclei. It is concluded that an important mechanism, whereby FUdR induces cleft palate in experimental animals, is by reducing cell proliferation and the rate of DNA synthesis in the palatal processes.

Animals↗
PubMed1989

'Locked-in' syndrome. Occurrence after coronary artery bypass graft surgery.

The 'locked-in' syndrome has not previously been described in the immediate period after open-heart surgery. We describe the case of a patient who remained tetraplegic and mute, but alert, after graft surgery. A brief review of the aetiological factors in the development of this type of stroke after coronary artery bypass is presented.

Coronary Artery Bypass↗
PubMed1988

The development of mast cells in facial skin, palate and tongue of the mouse.

This was examined in connective tissues of facial skin, palatal mucosa and tongue in fetal and adult mice. Mast cells were first observed in skin at 15 days of fetal age, but until 17 days in palate and tongue. With increasing age they increased in size and granularity. At birth they were 6-7 times more numerous per unit volume of tissue in skin compared with palate or tongue but, in the adult, numbers were similar in each region. Either mast cells enter developing tissues at different times or they differentiate and proliferate in some regions before they do so in others.

Animals↗
PubMed1988

Development and growth of palatal rugae in the mouse.

Palatal rugae began to develop in the mouse, before the elevation of the palatal shelves, as localized regions of epithelial proliferation and thickening. Subsequently, fibroblasts and collagen fibres accumulated in the connective tissue subjacent to the thickened epithelium and later assumed a distinctive orientation, the fibres running anteroposteriorly within the core and in concentric curves across the base of each ruga. The role of collagen in rugal morphogenesis was examined after inhibiting its formation by feeding the lathyritic agent beta-aminopropionitrile to pregnant females. This substance markedly affected the eventual height of the rugae at birth, confirming the importance of collagen in rugal development.

Animals↗
PubMed1986

A simulation approach to understanding the masticatory process.

An analysis of the reduction of food particle sizes during human mastication is presented in terms of the probability of a particle being broken (selection function) and the distribution of fragment sizes produced when it fails (breakage function). Both selection and breakage functions are defined and a general equation produced. Several feasible behaviours for these two variables that have been suggested in the literature are modelled by computer simulation and the results are compared to published breakdown patterns. The conclusions are that selection and breakage functions probably behave very simply with respect to particle size, and that these behaviours could be deduced from an analysis of food particle size distributions and the rate at which particle sizes are reduced per chew.

Computers↗
PubMed1986

Is food particle size a criterion for the initiation of swallowing?

A small study on fifteen subjects found that brazil nut particles always broke down much more rapidly per chew than raw carrot particles. Both foods were swallowed, on average, after similar numbers of chews. However, a relationship was found which suggested that subjects that swallowed after few chews took less for carrots than brazils and vice versa for those that took more chews. An extended study with carrot showed a significant correlation between the rate of size breakdown and the number of chews required for swallowing in dentate subjects (r = 0.69) but not in full denture wearers. The whole sample (n = 79 including six wearers of partial dentures) gave a significant correlation of r = 0.65. It is concluded that some consideration of the physical properties (texture) of foods is necessary before results from this type of study can be interpreted as relevant or not for dentistry.

Adolescent↗
PubMed1986

Food breakdown patterns produced by human subjects possessing artificial and natural teeth.

The abilities of thirty-two complete denture wearers and thirty-two dentate subjects to break down raw carrot particles were compared. The particle size distributions produced were broader in those subjects that broke down food rapidly per chew and, conversely, narrower in those that were slower. This did not appear to depend on dental status. An analysis of mastication as composed of two separable processes, one describing the means by which particles come to be broken (selection) and the other, the size distributions of a particle upon fracturing (breakage), indicated that both processes were variable. It is concluded that no qualitative differences in the manner by which the two groups reduce food is apparent. To support this, a small study on dentate subjects suggests the covering of the palatal mucosa with an acrylic plate does not affect masticatory performance.

Adult↗