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Biomedical subjects

B G Martin

Publications and source records attributed to B G Martin.

At least 37 records · Page 2Linked to original sources
PubMed1983

The effect of positive and negative air ions on bronchial asthma.

The effect of prolonged exposure to either positive or negative small air ions was studied in nine patients with bronchial asthma, of whom seven had reported increased respiratory symptoms in association with weather changes. On consecutive days, while grounded, patients were exposed for six hours to approximately 10,000/cc of either positive or negative ions. Pulmonary function, pulse and blood pressure were measured throughout the exposure. Questionnaires to assess emotional state and physical symptoms were completed after 15 minutes and five hours each day. Urinary 5-hydroxy indoleacetic acid (5HIAA) excretion was measured. Patients were continued on theophylline but adrenergics and corticosteroids were withheld. No patient experienced an exacerbation of asthma. Symptoms, pulmonary function, pulse and blood pressure, urinary 5HIAA excretion and the response to the questionnaires did not differ significantly between the two ion exposures. Thus moderately long exposure to positive or negative small air ions did not influence the clinical condition of these patients, many of whom reported exacerbations with weather changes. The findings do not support a significant role of small air ions in exacerbations or treatment of bronchial asthma.

Adult↗
PubMed1982

A matrix technic for comprehensive methods documentation.

This article presents an approach to total documentation of clinical laboratory methods that is practical and comprehensive. Primary reference documents including the bench method, all aspects of instrumentation, calibration, quality control, safety, results, and reporting conventions and back-up research data are entered into a matrix by section. This system has proved to be of great utility particularly in meeting regulatory demands and for the use and orientation of staff technologists.

Blood Banks↗
PubMed1979

Membrane specializations and cytoplasmic channels of Schwann cells in mammalian peripheral nerve as seen in freeze-fracture replicas.

Mammalian Schwann cells in rat, rabbit and human fetal nerves were studied using several cryoprotective agents for electron microscopic study of freeze-fracture replicas. The findings in fixed and unfixed tissue reveal surface plasmalemma caveolar specializations and the outer layer membrane junctional complexes found in non-mammalian species. The plasmalemma also reveals a complex arrangement of contours outlining cytoplasmic channel networks distinct from the long-recognized Schmidt-Lanterman incisures and paranodal cytoplasmic loops. A specialized interconnected channel system in the outer "loose" myelin layer displays relatively uniform dimensions comparable in diameter to nodal microvilli, paranodal loops and some incisures. An adaxonal tubular channel system constituting the "axon-Schwann network" is found in the internodal region in addition to other variants of the adaxonal Schwann plasmalemma. The several forms of sequestration of Schwann cell cytoplasm presumably underlie the specialized needs of cytoplasmic continuity in a dynamic functional entity in which large domains of cytoplasm have been displaced by the formation of compact myelin.

Animals↗
PubMed1976

The ultrastructural changes in the skin in dermatitis herpetiformis after withdrawal of dapsone.

The development of skin lesions in patients with dermatitis herpetiformis after the withdrawal of their dapsone therapy was studied with the electron microscope. In control biopsies from patients prior to cessation of treatment, membrane-bound vacuoles were found beneath the basal lamina of the epidermis as previously described. After dapsone withdrawal, there was an apparent increase in the number of vacuoles and occasionally several vacuoles appeared to have coalesced forming an early blister. At this stage, the basal lamina and associated hemidesmosomes were normal although in places there were small discontinuities in the basal lamina. Where the reaction was more intense, vacuoles and cells, mainly eosinophils, were embedded in fibrin de posits. Above this, the basal lamina was usually disrupted with involvement of the basal epidermal cells. These results suggest that the vacuoles do play a part in the formation of the pathological lesion in dermatitis herpetiformis. In addition, the basal lamina is shown to be only secondarily involved. The nature of the vacuoles has still to be elucidated.

Biopsy↗
PubMed1976

Ureteric vascular and muscle coat innervation in the rat. A quantitative ultrastructural study.

The application of a quantitative ultrastructural approach to the study of the innervation of the smooth muscle in the wall of the ureter of the rat has revealed major differences in the structure of the nerves in the muscle coat and in the walls of the arterioles. The high density of adrenergic terminals in the periarteriolar nerves is consistent with the distribution of many of the postganglionic sympathetic axons that run in the ureteric nerves to blood vessels and the low density of both adrenergic and cholinergic terminals in the intramuscular nerves implies that the autonomic nervous system plays only a secondary role in controlling the activity of the muscle. The mean size of the intramuscular nerves corresponds to that of the nerves in the submucosa and terminals of the kind that occur in the submucosal nerves are numerous. The function of axons with such terminals and their possible involvement in the transmission to the central nervous system of pain impulses is discussed.

Animals↗
PubMed1975

Comparative ultrastructure of the nerves innervating the muscle of the body of the bladder.

The distribution and structure of the nerves supplying the muscle of the body of the bladder in mammals such as the mouse, guinea-pig, rabbit, cat and dog was compared with that previously demonstrated in the rat. The muscle of the arterioles located between the muscle bundles is innervated by a fine perivascular plexus and the nerves forming the muscular plexus can be divided into inter- and intra-fascicular nerves and the intrafascicular nerves are characterised by large numbers of terminals with the features of those of cholinergic axons. In addition to many small clear vesicles, the cholinergic terminals contained some small dense-cored vesicles, and it is suggested that, as in the rat, these contain a second transmitter which is released with acetylcholine at the terminals during impulse transmission. Adrenergic term-nals are more common in the muscular plexuses of the guinea-pig, dog and cat than in those of the other animals studied and there is evidence for the presence of two types of such terminal in the nerves. Of these, one contains a much smaller proportion of small vesicles with dense cores and many more large dense-dored vesicles than the second, and the possibility of a relationship between such terminals and those of short adrenergic neurones and neurones associated with non-adrenergic patterns of impulse transmission is discussed.

Animals↗
PubMed1975

Comparative ultrastructure of ureteric innervation.

The distribution and structure of the ureteric nerves in a small series of mammals was compared with that previously demonstrated in the rat. There was marked interspecies variation in the extent to which the nerves penetrated the wall of the ureter and in the degree of development of the deep submucous plexus. In animals with a highly developed deep submucous plexus, terminal arterioles frequently passed through the muscle coat before breaking up into capillaries. These vessels were surrounded by a fine periarteriolar plexus and were accompanied in their course through the muscle coat by one or more branches of the adventitial nerves. Intramuscular nerves not related to arterioles contained few axons with terminals classifiable as either adrenergic or cholinergic, and in animals in which the muscle cells were arranged in fascicles rather than in sheets, the nerves were typically interfascicular in position. As in the rat, only the periarteriolar plexuses contained large numbers of adrenergic axons. Cholinergic axons were generally few, but were not uncommon in the deep submucous plexus when this was well-developed. The majority of the terminals encountered in the intramural nerves contained variable and usually small numbers of both clear and large dense-cored vesicles. The relationship between these terminals and those defined in the submucous nerves of the rat ureter was discussed and it was suggested that the marked variations in the diameter of the axons in the terminal areas and in the number of vesicles in the terminals were related to the effects of the mechanical and other derangements which occur during processing.

Animals↗
PubMed1975

Blockade of renin release by lanthanum.

1. The effects of lanthanum on renin release and renal vasoconstriction were studied in the isolated perfused rat kidney. 2. Lanthanum reduced noradrenaline-induced renal vasoconstriction. 3. Lanthanum prevented isoprenaline-induced and glucagon-induced stimulation of renin secretion.

Animals↗
PubMed1975

Ultrastructure of the submucous nerves of the rat ureter.

The fine structure and distribution of the nerves in the submucosa of the middle part of the ureter were studied in the adult rat. As in the rabbit, the nerves were concentrated on the inner surface of the muscle and beneath the epithelium. The nerves beneath the epithelium were smaller than those on the surface of the muscle, but they were much more numerous. They gave off small branches which ran for only short distances in the subepithelial connective tissue before terminating. Axonal varicosities were common and almost all appeared to represent the terminals of a single type of axon. The varicosities contained clusters of clear vesicles and variable numbers of larger dense-cored vesicles. The dense-cored vesicles were unaffected by short-term treatment with 6-OHDA and in this and other respects compared well with those of the terminals classified by Burnstock (1972) as purinergic. The possibility that the axons are sensory, and are the source of impulses which are recognized as being painful in nature, is discussed.

Animals↗