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Biomedical subjects

D Smith

Publications and source records attributed to D Smith.

At least 1,135 records · Page 63Linked to original sources
PubMed1980

Enhancement of tactile perception in palpation.

We studied tactile perception in palpation of the precordium to determine the frequency response of the hand and to improve, if possible, the sensitivity of the hand as a transducer for precordial movement. The threshold of tactile sensation was determined for 10 subjects by manipulating the amplitude of movement of an impulse generator at each of a series of frequency settings in the subaudible range (1-40 Hz.) Relatively gross movements were necessary to achieve threshold in the lowest frequencies. A more than four-fold increase in sensitivity was obtained by restraining the fingers with the application of a light but unyielding disc to their dorsal surface. Clinical application of this device permitted the easy perception of a systolic thrust as well as a rapid filling wave in normal adult subjects over the right ventricle at the left sternal edge, an area generally considered to be motionless by conventional palpation.

Hand↗
PubMed1980

Size of the subarachnoid space in stenosis of the lumbar canal.

Measurements of the subarachnoid space at myelography were carried out in three groups of patients, one group with stenosis of the lumbar spinal canal, one group without stenosis, and one intermediate group. Although spinal canal stenosis is most prominent at disc levels, the results demonstrate decreased sagittal diameter at mid-vertebral body level as well. The mean transverse diameters did not differ in three groups. This points towards congenital or developmental factors as the basic abnormality in the majority of patients with stenosis of the lumbar spinal canal.

Adolescent↗
PubMed1980

Vertebral body size in lumbar spinal canal stenosis.

The transverse and sagittal diameters of the lumbar vertebral bodies have been compared in patients with symptoms and myelographic findings consistent with stenosis of the lumbar canal, in patients with some narrowing of the lumbar canal, and in patients without clinical or myelographic indication of stenosis. No significant difference in the measured diameters was found.

Female↗
PubMed1980

Arachnoidal diverticula and cystlike dilatations of the nerve-root sheaths in lumbar myelography.

Diverticulum-like widening of one or several nerve-root sheaths was found in 24 of 136 patients examined by lumbar myelography. No clinical significance of the diverticula was demonstrated. The roots most commonly affected were the S 1 and S 2 roots, carrying approximately 60 per cent of the diverticula. A system of classification according to morphology and to size compared with the root involved is proposed. A relationship between magasac and arachnoidal diverticula is confirmed.

Arachnoid↗
PubMed1980

Fibronectin presence in native collagen fibrils of human fibroblasts: immunoperoxidase and immunoferritin localization.

Fibronectin is a major constituent of the fibroblast extracellular matrix. Fibronectin binds to collagen, mediates fibroblast adhesion to collagen, and is synthesized and secreted into the medium of cultured fibroblasts. Affinity-purified antibodies to fibronectin and collagen were localized using the peroxidase-antiperoxidase method or with ferritin-coupled secondary antibodies. Using human fibroblasts cultured under routine conditions, fibronectin and procollagen I react in a nonperiodic manner with: 1) approximately 10 nm extracellular fibrils, 2) cell membrane, and 3) membrane-associated vesicles. All fibrils react with both antibodies, suggesting some form of codistribution of fibronectin and collagen in these fibrils. Treatment with ascorbate leads to the development of a larger diameter extracellular fibril, approximately 40 nm in diameter. These large diameter fibrils are clearly collagen fibrils as documented by the procollagen antibody reaction. Importantly, fibronectin is bound to or a constituent of these "native" or cellular made collagen fibrils. Fibronectin and procollagen antibodies localized with the peroxidase-antiperoxidase method have a 70 nm axial repeat of reaction product on ascorbate-treated fibroblasts. Localization of antibodies with ferritin-labeled secondary antibodies is less satisfactory, but supports the basic observations made with the unlabeled antibody enzyme method. This observation rules out any potential criticisms. Although it is more difficult to observe with immunoferritin, there is an indication that antibodies to fibronectin react with an axial periodicity on cellular produced collagen fibrils.

Collagen↗
PubMed1980

Neuronal cell damage in the brain: possible involvement of oxidative mechanisms.

Neuronal lesions in the brain occur in conditions associated with a reduced supply of oxygen (hypoxia and ischemia) and glucose (hypoglycemia) as well as in those associated with a pathologically enhanced neuronal activity (status epilepticus). In only two of these conditions (hypoxia and ischemia) are the lesions correlated to cellular oxygen lack, and gross energy failure is absent in one condition (status epilepticus). Although anaerobic mechanisms seem responsible for the cell injury in hypoxia and ischemia, oxidative mechanisms could operate in hypoglycemia and status epilepticus. Since the supply of oxygen has not ceased altogether in hypoxia and incomplete ischemia, and since reoxygenation/recirculation leads to a transient increase in tissue oxygen tensions, one cannot exclude the possibility that oxidative mechanisms contribute to the final damage following all types of cellular oxygen lack. We have failed to obtain evidence that peroxidative degradation of cellular constituents occurs in hypoglycemia and status epilepticus. Thus, there is neither a perturbation of the redox state of the glutathione pool of the tissue nor a measurable degradation of polyenoic phospholipid-bound fatty acids. It is emphasized that the cascade of events triggered by an accumulation of free polyenoic fatty acids, mainly arachidonic acid, may contribute to cell lesions by leading to cell edema and/or microcirculatory changes. During seizures, such an accumulation occurs even though energy failure is moderate and it may conceivably contribute to cell damage. In general, though, mechanisms of cell damage in the brain remain partly elusive.

Animals↗
PubMed1979

Playing consequences.

Explore the source record for details and available documents.

Regional Health Planning↗
PubMed1979

Joint care: promoting the generalist.

A new model of personal social service based on primary care and covering every citizen, with or without problems, is suggested by author. This, he feels, would make up for the inadequacies of the present service.

Continuity of Patient Care↗
PubMed1979

On the symmetry and asymmetry of the bifurcation of the common carotid artery: a study of bilateral carotid angiograms in 100 adults.

Bilateral carotid angiograms of the neck in 100 consecutive adult patients show the bifurcation of the left common carotid artery to be located cranial to the right in 50% of the cases, while the right bifurcation was higher in 22%. The origin of the internal carotid artery was at the dorsal or dorsolateral aspect of the common carotid artery in 82% on the right side and in 94% on the left, while a dorsomedial or medial origin was found in 18% on the right side and in 6% on the left.

Adult↗