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Biomedical subjects

D Robertson

Publications and source records attributed to D Robertson.

At least 505 records · Page 28Linked to original sources
PubMed1977

A community-based continuing care program for the elderly disabled: an evaluation of planned intermittent hospital readmission.

Fifty of 217 patients on the Continuing Care Program of a Department of Geriatric Medicine have been studied in detail. All patients had sufficient disability to justify permanent admission to a traditional long stay or chronic unit. Utilizing flexible community-supporting services integrated with a hospital-based program of planned intermittent relief of the patients' supporters, patients were maintained in the community at an average cost of 79.5 hospital bed days per patient per annum. Within the near future, unprecedented numbers of persons over 75 years of age, with a high prevalence of chronic disability, will become the financial responsibility of health care systems of Western countries. The Continuing Care Program described may help contain the increasing demand for permanent admission to hospital and allow the disabled elderly citizen an alternative to institutionalization.

Aged↗
PubMed1977

Differential enhancement of early and late components of the cerebral somatosensory evoked potentials during forced-paced cognitive tasks in man.

1. Cerebral potentials evoked by random sequences of electrical stimuli to four fingers were recorded in intact man performing selective attention tasks. Eye movements and other artifacts were excluded from the averaged traces. Different finger stimuli were designated as targets to be mentally counted in alternate runs of each experiment. The high mean random rate of stimuli (150/min) fully involved the processing capacities of the subject. Vigilance changes or differential expectancy effects were excluded by the reciprocal random design with four different sensory channels. Task-related enhancements of somatosensory evoked potentials (s.e.p.) components were estimated by comparison with the s.e.p.s to physically identical finger stimuli recorded in runs when the subject attended signals in the opposite hand. The experimental design avoided subject's fatigue.2. The primary s.e.p. components N(20) and P(45) were not significantly influenced and this excluded centrifugal gating of the corticipetal signals as a mechanism.3. The earliest task-related changes in s.e.p. occurred 55-135 msec (mean 77.7 msec) after the target finger stimuli. In most cases the negative N(140) component was markedly enhanced both for target signals and for non-targets in the adjacent finger of the same hand. However, in several subjects the targets elicited a positive P(100) component instead. Both N(104) and P(100) were larger at the contralateral parietal focus than ipsilaterally. They were definitely smaller at the vertex and frontal scalp locations.4. Enhancements of N(140) were not observed in similar random four-finger experiments carried out at a 4 times slower mean rate, but they occurred in a bisensory paradigm with finger shocks and acoustic clicks at that slower rate.5. A large positive P(400) component was only elicited by target stimuli. Its voltage was maximum over the parietal region and was equal on both sides.6. At least three categories of components can be differentiated in the cortical s.e.p. on the basis of their time domains (roughly 18-70 msec, 70 to 200-250 msec and over 200 msec after the finger stimuli), cerebral hemispheres topography and cognitive parameters. Verbal instructions defining specific perceptual tasks can to a large extent switch on and off the components of the second and third categories when the processing resources of motivated subjects are fully committed in a well designed forced paced paradigm. In certain individuals physiological evidence for a different ;stimulus set' processing of target (P(100)) and non-target (N(140)) signals was documented for the first time.

Adult↗
PubMed1977

Predicting mortality after elective abdominal aortic aneurysmectomy in the elderly.

40 non-emergency cases of abdominal aortic aneurysmectomy were reviewed. Of the 20 cases who died during the follow-up period, a significant number had more evidence of pre-existing multiple diseases than had the survivors. The results of the study suggest that there is an association between the amount of coincident disease, length of survival, and mortality following elective abdominal aortic aneurysmectomy.

Age Factors↗
PubMed1977

A comparison of real-time, two dimensional echocardiography and cineangiography in detecting left ventricular asynergy.

Left ventricular wall motion was assessed in 105 consecutive patients both invasively, using biplane cineangiography, and noninvasively, by a real-time, phased-array, two-dimensional echocardiography system. Ventricular wall motion in five anatomic areas of the ventricle (anterolateral, posterolateral, apical, septal, and inferior) was analyzed by both methods in a double-blind manner. Two-dimensional echocardiographic images were deemed adequate for analysis in 82% of the regions (430 of 525). Fifty-five discrepancies were noted in the comparison of the remaining 430 regions. The reasons for discrepancies in interpretation between the two methods were established for 54 during retrospective review: 33 were due to echocardiography (inadequate target visualization, observer error, or tangential echo views). Fifteen were related to angiography (overlay of silhouettes or observer error), and six were due to other reasons including definition problems or spatial orientation difficulties. Both real-time, two-dimensional echocardiography and cineangiography have advantages and disadvantages. The techniques used together could provide more complete information concerning ventricular wall movement than is now currently available.

Cineangiography↗
PubMed1977

The effect of the Valsalva maneuver on echocardiographic dimensions in man.

Physiologic changes in the circulatory system caused by performing the Valsalva maneuver are blunted or absent in patients with congestive heart failure. Previously there has been no noninvasive method for examining cardiac chamber size during this maneuver. M-mode echocardiography was used to evaluate possible changes in cardiac chamber dimensions in 12 normal subjects (group I) and 15 patients with cardiovascular disease (group II). In group I, the left ventricular end-diastolic dimension decreased 11.2% (+/- 1.5%) and the end-systolic dimension 9.5% (+/- 1.32%), with a fall in stroke volume of 29%. The left atrial (LA) dimension decreased 30%. In group II, only the response of the LA dimension is reported. There was a diminished response to Valsalva related to the severity of congestive heart failure. Patients in NYHA classes III and IV decreased LA dimension by only 3.8%, significantly less (P less than 0.001) than those in classes I and II who had essentially normal responses. Echocardiographically-determined changes in left atrial size in response to the Valsalva maneuver may provide an objective, noninvasive means of evaluating and following patients with suspected or proven congestive heart failure. Possible mechanisms for the changes observed are discussed.

Adult↗
PubMed1977

Tonometry screening on the medical service.

Screening for glaucoma by Schiotz tonometry was carried out for two years on a general medical service. Of the 61% of patients who were over the age of 45 years, 5.5% had pressures equal to or greater than 21 mm Hg and were referred for ophthalmologic evaluation; 44% of those referred were diagnosed as having glaucoma or suspected glaucoma. The overall prevalence of glaucoma in patients on the general medical inpatient service was 3.3%. Because of the high prevalence of glaucoma in the population surveyed, the low incidence of side-effects of tonometry, the small amount of time required to perform tonometry, and the relatively high percentage of glaucoma patients found by routine tonometry used regularly, the present experience supports the view that Schiotz tonometry is a useful procedure for the internist to perform.

Evaluation Studies as Topic↗
PubMed1976

Possible relation between structure and spike shapes of neurones in guinea pig cochlear ganglion.

A two-component positive single unit spike could be recorded extracellularly from neurones in the acoustic ganglion of the guinea pig cochlea. Light and electron microscopy showed that the bipolar afferent neurones and their processes were myelinated except at nodes of Ranvier on either side of the cell soma, about 40 mum from the point of emergence of the myelinated processes. This anatomical finding and the properties of the two-component spike suggest that impulse conduction in these cells is achieved by rapid successive activation of the low threshold nodes on either side of the cell soma. The possible advantages of such a conduction system are discussed.

Animals↗