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Biomedical subjects

J R Martin

Publications and source records attributed to J R Martin.

At least 235 records · Page 13Linked to original sources
PubMed1977

Rapid urease test for mycobacteria: preliminary observations.

A rapid and sensitive urease test for mycobacteria utilizing a cumulative radiometric technique is described. Definitive results were obtained within a 30-min incubation period. The procedure is simple and economical. Technical time involved is no greater than in conventional procedures.

Bacteriological Techniques↗
PubMed1977

Fortimicins A and B, new aminoglycoside antibiotics. III. Structural identification.

The structures of fortimicins A and B have been determined by PMR, CMR, mass spectra and CD combined with chemical degradations. Both antibiotics are pseudodisaccharides and incorporate a novel aminocyclitol, fortamine. In contrast to the diaminocyclitol moieties of known aminoglycosides, fortamine is a 1,4-diamine, contains both N- and O-methyl groups and possesses chiro stereochemistry. Both antibiotics are glycosides of 6-epi-purpurosamine B, but fortimicin A differs from fortimicin B by being a glycyl amide.

Aminoglycosides↗
PubMed1976

Painful diabetic neuropathy. A morphometric study.

We investigated three diabetic patients whose neuropathy was characterized by pain, hypesthesia, and autonomic dysfunction, with preservation of epicritic sensation and muscle-stretch reflexes. Two sural nerves were studied qualitatively and quantitatively, using teased fiber, light, and electron microscopical techniques. The most striking alterations were encountered in unmyelinated and small myelinated fibers. Unmyelinated nerve fiber sprouting was evident. The clinical features, which suggested small-fiber involvement, correlated with the pathological findings in biopsied cutaneous nerve. The balance of evidence indicates that the painful small-fiber neuropathy of diabetes is an axonal disorder.

Adult↗
PubMed1976

A review of concepts of silver amalgam retention.

Retention grooves and undercuts are not advantageous to an amalgam cavity preparation. These mechanical locks do not prevent fracture of the proximal portion in vivo, do not inhibit marginal fracture, are not necessary for retention, and are a factor in the split-tooth syndrome. The tensile stress needed to dislodge the restorations would be impossible to achieve in the oral environment, and therefore, additional retention is not worth the added risk of endangering the integrity of the tooth and the pulp. All factors considered, a properly prepared, conservative Class II Black's type of cavity preparation not only remains the easiest to prepare with conventional instrumentation but also is totally adequate to withstand the stresses of mastication, magnifying the desirable properties of the amalgam restoration.

Dental Amalgam↗
PubMed1976

Motivated behaviors elicited from hypothalamus, midbrain, and pons of the guinea pig (Cavia porcellus).

Eating, drinking, biting attack, male mating behavior, and gnawing were elicited by electrical stimulation through electrodes located predominantly in a region extending from the preoptic area through the lateral hypothalamus into the ventral midbrain. Escape and digging were elicited from a parallel but more medial region that overlapped the lateral zone only in the preoptic-anterior hypothalamic area. Several differentiable vocalizations were produced from sites distributed through most, although not all, areas explored. Sites yielding painlike responses were located principally in the vicinity of the presumed pain pathway traced after anterolateral cordotomy in other species. Reward was obtained from widespread sites that were generally congruent with catecholaminergic systems as described in the rat. Although there was considerable overlap of the effective zones for many responses, their underlying mechanisms were differentiated anatomically by localized differences in their distribution or functionally by the elicitation of pure responses from some electrodes. Response mechanisms localized in the brain stem of the guinea pig generally resembled those in the rat, although there were differences in details, especially in the posterior midbrain and pons.

Aggression↗