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Biomedical subjects

D Doyle

Publications and source records attributed to D Doyle.

At least 145 records · Page 8Linked to original sources
PubMed1983

Fifty-four months' experience with an improved tilting disk valve (Medtronic-Hall).

Between 1978 and 1982, 230 consecutive patients underwent valve replacement with the Medtronic-Hall valve prosthesis. There were 95 patients with aortic valve replacement (AVR), 107 with mitral valve replacement (MVR) and 28 with aortic and mitral valve replacement (DVR). Operative mortality was 7.8%. Follow-up studies included 212 patients with a mean follow-up time of 26.5 months. Incidence of thromboembolism was 1.2%/patient year after AVR, 2.4%/patient year after MVR and 0 after DVR. Freedom from any kind of complications was 80% at 3 years. Recatheterization showed mean pressure gradients of between 0.0 and 6.0 mmHg in aortic prostheses and between 0.0 and 3.5 mmHg in mitral prostheses. It is concluded that the Medtronic-Hall valve prosthesis is a durable substitute with a low complication rate and good hemodynamic performance.

Adult↗
PubMed1983

Establishment of plasma membrane domains in hepatocytes. I. Characterization and localization to the bile canaliculus of three antigens externally oriented in the plasma membrane.

A membrane fraction denoted N2 upper was isolated from homogenates of rat liver by sucrose gradient centrifugation. This fraction, which was enriched 65-fold over the homogenate in 5'-nucleotidase activity, was used as an immunogen in goats. The antisera obtained contained antibodies to three predominant polypeptides in the N2 upper membrane fraction, as shown by crossed immunoelectrophoresis. These polypeptides had molecular weights of 105,000, 110,000, and 160,000 after recovery from the crossed immunoelectrophoretic gels and are denoted PM105, PM110, and PM160. Each was a distinct polypeptide, as shown by the distinct peptide patterns resulting from limited proteolysis in the presence of detergents. The three polypeptides were synthesized by primary cultures of hepatocytes and were externally oriented at the surface of these cells, as shown by their accessibility in situ to iodination catalyzed by lactoperoxidase. They were not detectable in the serum by crossed immunoelectrophoresis. The three antigens were present at very low (PM110) or nondetectable (PM105, PM160) concentrations in intracellular membrane fractions derived from the Golgi and smooth and rough endoplasmic reticulum of liver. The antigens also were reduced in concentration in a plasma membrane fraction most likely derived from the sinusoidal surface of the hepatocyte. The three membrane antigens bind to concanavalin A; hence, they are probably glycoprotein constituents of a discrete domain of the hepatocyte plasma membrane. Immune complexes were isolated after crossed immunoelectrophoresis and injected into rabbits. Each of the antisera obtained was reactive to one of the membrane polypeptides. Sections of fixed rat livers were reacted with each of the antibodies and then the primary antibody was localized by indirect immunocytochemical methods using horseradish peroxidase or colloidal gold as labels. Each of the three antigens was localized by this method to the bile canalicular domain of the hepatocyte plasma membrane.

Animals↗
PubMed1983

Glioma of the optic chiasm and its management.

The clinical features, radiological investigation and pathology of 9 cases of glioma of the optic chiasm are described and the place of radiotherapy in their management considered.

Adolescent↗
PubMed1983

The oxygen cost of an escape from an underground coal mine.

Six 27- to 63-year-old coal miners performed an "escape" maneuver from an underground mine along a passageway that required walking and running erect or stooped, duck walking and crawling. The miners traveled at different speeds, for each mode of locomotion. The minute pulmonary ventilation (VE), O2 uptake (VO2) and heart rate (HR), recorded continuously on a magnetic tape via lightweight meters carried on the miners' waists, indicated similar average and peak values for all modes of locomotion. The mean VE, VO2 (L X min1, STPD) and HR (b X min1) were, respectively, 49, 1.63 and 143 for the average values, and 52, 1.92 and 161 for the peak values. Compared to the aerobic capacity obtained during graded treadmill test to exhaustion, the average effort of the "escape" was performed at 64% and the peak effort at 70% of the miners aerobic capacity for an "escape" time of 58 minutes.

Adult↗
PubMed1982

Morphologic and functional evidence of reinnervation of the gastric parietal cell mass after parietal cell vagotomy.

The incidence of recurrent ulceration after parietal cell vagotomy varies greatly and the cause is largely unknown. Whether the vagus nerve can regenerate or reinnervate the gastric parietal cell mass after parietal cell vagotomy was investigated. Careful microscopic dissection of the neurovascular bundle in 130 rats allowed the vagus nerve to be divided to the gastric body with preservation of the antropyloric nerve and gastric vasculature. Gastric secretory tests were performed under basal and stimulated conditions after secretagogue and insulin hypoglycemia stimulation. Rats were killed weekly and the vagal nerve distribution examined by electron microscopy. Stimulated gastric acid output decreased from 164 to 26 mumol/hour immediately after operation (p less than 0.001). One week after parietal cell vagotomy the nerves were swollen with fibroblast infiltration and collagen around axon groups showed degeneration. By the third week after parietal cell vagotomy, the axons were more densely packed with neurofilaments and acid output had increased to 183 mumol/hour. In the fourth and fifth weeks, the enlarged Schwann cell processes had more axons and acid output increased to 262 mumol/hour. By the seventh week, both large and small axons were identified and the acid output was 93 percent higher than the preoperative level (p less than 0.001). The sequential neuropathologic changes of vagus nerve degeneration, regeneration and functional reinnervation of the gastric parietal cell mass after parietal cell vagotomy are shown by this study. If this occurs in man, it may be an important cause of recurrent peptic ulceration after parietal cell vagotomy.

Animals↗
PubMed1982

Hospice--an education center for professionals.

The need for further improved professional training in the care of the dying is now being recognized by doctors themselves, and increasingly they are turning to hospices for such education. The ways in which such training might be provided are outlined and some of the problems discussed in the light of British experience. It is suggested that no major hospice program should ever be initiated unless it incorporates an education program aimed to meet the deficiencies revealed in recent studies.

Awareness↗
PubMed1982

Synovial fluid lactic acid measurement in the diagnosis and management of septic arthritis.

An improved method of lactic acid estimation by gas liquid chromatography (GLC) is described. Synovial fluid lactic acid estimation was performed on 52 patients (15 with septic arthritis and 37 with non-septic arthropathies) and compared to routine microbiological methods and white cell counts. Lactic acid was found to be a useful and rapid test for differentiating between septic and non-septic arthritis being markedly raised (greater than 12 mmol/l) in all the septic joints. Raised lactic acid concentrations were of particular diagnostic value in patients in whom antibiotic therapy had commenced before joint aspiration. The results of lactic acid estimation on sequential samples were helpful in assessing the response of septic arthritis to treatment.

Arthritis↗
PubMed1982

Anterior horn cell dysfunction in Alzheimer's disease.

Electrophysiological studies were undertaken on 29 patients with Alzheimer's Disease. A reduction in the number of functioning motor units was found in the extensor digitorum brevis muscle. The electrophysiological parameters of the motor unit potentials were increased compared to control values. Four of seven muscle biopsies showed abnormalities ranging from mild to severe. The results suggest dysfunction in the lower motor neurone in this disease.

Aged↗
PubMed1982

Domiciliary terminal care: demands on statutory services.

The work of a specialist advisory home care service for the terminally ill during 1980 is reported, with reference to the demands it made on community services. Whilst there was no change in demand for home helps, there was a 44 per cent increase in visiting by community nurses for male patients and a 117 per cent increase for female patients. Commodes, ripple mattresses and backrests were all essential and an increased need of over 100 per cent in each was recorded. Patients were attended on average for three months (men) and six months (women) and 41 per cent were able to remain at home until their death.

Adolescent↗
PubMed1982

Education in terminal care.

A survey of the education in terminal care received by a wide range of doctors in Scotland showed that clinical instruction in the physical and emotional aspects of the care of the dying had been generally inadequate, and that the educational influence of a special unit or hospice could be significant. Doctors who had undertaken traineeships in general practice tended to have had more comprehensive training in terminal care-and to be more enthusiastic about further education-than others. We conclude that planned vocational training schemes in all disciplines need to be re-examined for the provision they make for education in terminal care, and that continuing education in the subject may need to be improved for all doctors.

Consultants↗