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Biomedical subjects

V James

Publications and source records attributed to V James.

60 records · Page 4Linked to original sources
PubMed1971

A new method of destroying adrenergic nerves in adult animals using guanethidine.

1. The structure of sympathetic neurones in the rat has been examined with histological, fluorescence histochemical and electron microscopical methods after chronic treatment for 6 weeks with guanethidine (25 or 30 mg/kg/day i.p.).2. Less than 2% of the nerve cell bodies in the superior cervical ganglion remained at this time and in these cells the mitochondria were badly damaged. Few fluorescent adrenergic nerve fibres were found outside the central nervous system. This situation persisted even 4 months (the longest period studied) after cessation of treatment.3. This procedure is proposed as a new method of producing sympathectomy. It has the advantage of being applicable to adult animals in a variety of experimental and pathological situations. It is uniquely advantageous for denervation of the male reproductive tract.

Animals↗
PubMedDate not supplied

Immunolocalization of elastin, collagen type I and type III, fibronectin, and vitronectin in extracellular matrix components of normal and myxomatous mitral heart valve chordae tendineae.

The identification, distribution, and localization of matrix proteins and the proteins associated with normal and degenerated elastic fibers and collagen fibrils of myxomatous chordae tendineae were studied with immunoelectron microscopy. Ultrathin sections of L R White-embedded tissue were processed by indirect immunogold cytochemistry using primary antibodies against human alpha elastin, collagen types I and III, fibronectin, and vitronectin. In normal chordae tendineae, alpha elastin antibody heavily labeled the elastic fibers in spongiosa and fibrosa, but microfibrils around them were not labeled. Antibodies to collagen type I, collagen type III, and fibronectin all labeled the collagen fibers and microfibrils in the spongiosa. Fibronectin antibody labeling was higher than collagen type III, whereas labeling by anticollagen type I was lower. Intense labeling by vitronectin was observed on the microfibrils in the spongiosa and on electron-dense material around elastic fibers in the spongiosa and fibrosa. In myxomatous chordae tendineae, alpha elastin antibody heavily labeled degenerated elastic fibers, previously unidentified reticulated structures, and other moderately electron-dense material, both in the spongiosa and in the fibrosa, but not the electron-dense fibrous material around them. Antibodies to collagen types I, III, and fibronectin heavy labeled electron-dense aggregates of fibrous material. Vitronectin labeling was observed on electron-dense longitudinally running microfibrils and on the electron-dense microfibrils around degenerated elastic fibers.

Aged↗
PubMedDate not supplied

Ultrastructure abnormalities in proteoglycans, collagen fibrils, and elastic fibers in normal and myxomatous mitral valve chordae tendineae.

Normal and myxomatous chordae tendineae were studied using light and electron microscopy, to assess the alterations in the appearance and mutual arrangement of proteoglycans, collagen fibrils, and elastic fibers. Specific staining with ruthenium red and cuprolinic blue in a critical electrolyte concentration mode were used to localize proteoglycans. Fresh tissues were fixed in glutaraldehyde containing the cationic dyes and embedded into Spurr resin. Semithin sections of LR White (London Resin Co., Basingstoke, U.K.)-embedded tissue were used for histochemistry. In normal chordae tendineae, the fibrosa comprised close-packed collagen fibrils intermixed with elastic fibers. These were surrounded by a thin layer of elastic fibers and collagen fibrils, both of which were closely associated with proteoglycans. In myxomatous chordae tendineae, alterations were observed in the connective tissue. Proteoglycans were more abundant and were distributed throughout the tissue. The outermost layer was transformed into an undifferentiated electron-dense mass surrounding the central fibrosa, which contained degraded elastic fibers and collagen fibrils. Collagen fibrils had faint banding or lacked a banding pattern altogether. Spaces between collagen fibrils were occupied by abnormal proteoglycans or proteoglycan aggregates. Elastic fibers showed varying degrees of degeneration and were occasionally replaced by electron-lucent spaces containing microfibrils. Accumulation of abnormal proteoglycan was also observed around degenerated elastic fibres and collagen fibrils.

Aged↗
PubMedDate not supplied

Health care provision: the six key players.

The new language of health care tends to assume a duality between purchasers and providers. This article argues that, in fact, a plurality of groups are involved with health services. These include not only purchasers and providers, but politicians, policy developers, practitioners and punters. The author suggests that attention should be focused on the true experience of health services, where practitioners and punters meet.

Delivery of Health Care↗