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Biomedical subjects

J Boss

Publications and source records attributed to J Boss.

30 records · Page 2Linked to original sources
PubMed1980

Structural changes in the perfused canine kidney exposed to the direct action of endotoxin.

We attempted to clarify whether structural damage or hemodynamic alterations is the primary cause of renal failure in the initial phases of endotoxic shock. Endotoxin (0.5 mg/kg) was infused directly into the renal artery and normal renal hemodynamics were maintained by cross-perfusion and controlled pressure. Direct exposure of renal parenchyma to endotoxin action was followed by changes in structure at the cellular and subcellular levels. The damage was unequally distributed and involved mainly the mitochondria and lysosomes of the distal and proximal convoluted tubules. No significant structural changes could be detected in the glomeruli or in the vascular compartment. There was no direct relationship between the degree of mitochondrial and lysosomal damage and the changes in enzymatic activity. The enzymatic systems associated with active Na transport and glycogen breakdown showed only slight alterations, while those related to energy production, hydrogen transfer and the respiratory activity of the cell were severely affected. These results indicate that structural damage in the nephron may contribute to the renal failure in the initial phase of endotoxemia.

Acid Phosphatase↗
PubMed1979

Thymic deficiency in Down's syndrome.

Children with Down's syndrome (DS) often have small and abnormal thymuses, with lymphocyte depletion, diminution of the cortex, and loss of corticomedullary demarcation--a picture resembling thymic involution. Besides this, they have markedly enlarged Hassall's corpuscles, some surrounded by a sheath of lymphocytes. Patients with DS are known to have increased numbers of respiratory infections; they also have a higher incidence of lymphatic leukemia than do individuals who do not have DS. Studies of cell-mediated (thymic-dependent) immunity demonstrate that children with DS have both diminished numbers of T cells as well as functional deficiency of these cells.

Child↗
PubMed1978

A method for photographic densitometry of scanning electron micrographs.

A method is described for the study of the surface structure of mammalian chromosomes. Densitometric analysis of scanning electron micrographs permits the detection of regularities where overlying material obscures these in directly inspected micrographs. The method has been applied to the study of mammalian chromosomes.

Animals↗
PubMedDate not supplied

Ligament and tendon substitution with composite carbon fiber strands.

Carbon fiber strands were used experimentally to substitute for tendons in dogs and clinically to reconstruct tendons and ligaments in human. The investigation was carried out to determine the histologic appearance of the new composite structure and its tensile strength in comparison to the natural structure. The histologic picture disclosed a remarkable structure evolved by continuous irritation of the carbon fibers and consisting of two interrelated components: synthetic carbon fibers and biologic collagenous tissue. This carbon fiber composite structure was composed of long cylindrical units containing concentric layers of collagenous fibers and cells enveloping the core of each carbon fiber. After one year of physiologic use in dogs, the average ultimate tensile strength of the composite structure which replaced the quadriceps and triceps was 372 N, or 88% the strength of the natural tendons. One year after implantation the histologic picture of the composite structure in human showed a relatively dense collagenous architecture. However, a significant proportion of the structure was taken up by histiofibroblasts produced by the irritation of the carbon fibers. Thus, the density of the collagen in the composite structure remained relatively deficient in comparison to the nature tendon, and the structural tensile strength continued to depend entirely on the integrity of the carbon fibers.

Animals↗
PubMedDate not supplied

The medical philosophy of Francis Bacon (1561-1626).

Francis Bacon's view of man is dualistic but, although he takes note of mental faculties, he makes the relation between mind and body, rather than the substance of mind, the basis for enquiry into mental processes and, more particularly, for the medically relevant study of mind. (He uses "mind" and "soul" as equivalent terms.) The healing of the body requires study of the body, and the ineffectiveness of physicians is due to their failure in this respect rather than to the body's complexity. To learn about the body requires clinical observation and recording, together with the comparison of bodies, experiments on living animals and attention to pathological changes. The aims of medicine should include not only the restoration of health but also the relief of suffering and they are not to be limited by putting aside a disease as incurable. To learn from treatment it must be fixed in its ordering with controlled and limited variation. Bacon has no separation of medicine from natural science; his philosophy of medicine is his general philosophy of the advancement of knowledge, but limited to a particular field of application. If medicine is separated from natural philosophy it is changed wholly or greatly into empiricism.

England↗