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Biomedical subjects

J R Martin

Publications and source records attributed to J R Martin.

At least 217 records · Page 12Linked to original sources
PubMed1979

Coeliactomy: differential toxiphobia conditioning with apomorphine and copper sulfate.

Thirsty coeliac ganglionectomized and sham operated rats consumed more of a novel fluid after a series of presentations, each followed by saline injection, than when apomorphine was injected or copper sulfate intragastrically intubated. Sham rats drank significantly more of this novel solution than ganglionectomized rats following treatments with a very low dose of the peripherally-acting emetic copper sulfate that locally irritates the gastric mucosa. However, sham and ganglionectomized rats drank comparable amounts of the novel fluid following treatments with saline and the two groups drank comparable amounts following treatments with the centrally-acting emetic apomorphine. The results suggest that coeliac ganglionectomy eliminates some, but not all, of the afferent nerves transmitting information concerning visceral toxicosis (produced with intragastric copper sulfate) to the brain.

Animals↗
PubMed1979

Pathogenesis of visna. IV. Spinal fluid studies.

Visna is a persistent retrovirus infection of sheep which produces a chronic progressive paralytic disease after an incubation period lasting from months to years. The cerebrospinal fluid (CSF) was repeatedly sampled in a group of Icelandic sheep which were infected intracerebrally and followed up to 42 months. Minimal levels of infectious virus were isolated from the cerebrospinal fluid (CSF) up to 4 months after infection after which CSF neutralizing antibodies appeared in many sheep. These antibodies varied in titer and in some animals exceeded serum antibody levels which were moderate to high. CSF antibody is apparently produced within the CNS by local proliferation of B cell clones, and is accompanied by the appearance of considerable numbers of plasma cells in the neural parenchyma. Some sheep raised serum antibody to a second serotype of visna virus and in a number of these animals heterotypic antibody was also found in the CSF. An increase in CSF leukocytes often occurs within 1 to 3 months following infection and may then persist or wane. A persistent high level of CSF cells is an indicator of progressive CNS disease and such animals are more likely to yield virus, have higher CSF antibody levels, more severe CNS lesions, and an enhanced risk of clinical illness (progressive paralysis). CSF cells are predominantly macrophages and lymphocytes, with a consistent minority of plasma cells.

Animals↗
PubMed1979

4-N-Aminoacylfortimicins E.

The conversion of fortimicin E, a minor metabolite from the Micromonospora olivoasterospora fermentation which also produces fortimicin A and fortimicin B, to four 4-N-aminoacylfortimicins E was accomplished. The new 4-N-aminoacylfortimicins E showed only weak antimicrobial activity against several Gram-negative and Gram-positive microorganisms.

Aminoglycosides↗
PubMed1978

Rapid Tween 80 hydrolysis test for mycobacteria.

A rapid Tween 80 hydrolysis test for mycobacteria utilizing gas-liquid chromatography is described. The test requires 1 h of incubation followed by simple extraction and chromatography of nonderivatized oleic acid.

Bacteriological Techniques↗
PubMed1978

Loss of glucagon suppression of feeding after vagotomy in rats.

Infusion of pancreatic glucagon through the hepatic-portal vein decreased short-term food intake in sham-vagotomized but not in subdiaphragmatically vagotomized rats. Measurement of hepatic glycogen storage showed that vagotomized rats maintain a lower glycogen level than control animals over the four fasting periods evaluated. To determine whether the absence of a glucagon effect on feeding in vagotomized rats was the result of the reduced amount of substrate for glycogenolysis, vagotomized rats were not fasted and control animals were food deprived for 8h to produce comparable hepatic glycogen levels. Hepatic-portal infusion of glucagon into these differentially fasted animals suppressed feeding in control rats but not in vagotomized rats. It is concluded that the ineffectiveness of glucagon in suppressing feeding in vagotomized rats is not due to reduced concentration of hepatic glycogen. Instead, it is likely that glucagon induces glycogenolysis, but the glucose, or some other correlate of glycogen breakdown, loses its ability to produce satiety subsequent to vagotomy.

Animals↗
PubMed1978

The structures of the m-chloroperbenzoic acid oxidation products of 8,9-anhydroerythromycins A- and B-6,9-hemiacetal and of (8S)-8-hydroxyerythromycin B.

13C-NMR studies have confirmed the structures of (8S)-8-hydroxyerythromycins A- and B-6,9;9,11-acetal proposed by KROWICKI and ZAMOJSKI2,3) for the products of the m-chloroperbenzoic acid oxidation of 8,9-anhydroerythromycins A- and B-6,9-hemiacetal. The preparations of (8S)-8-methylthiomethoxy- and (8S)-8-methoxyerythromycin B-6,9;9,11-acetals are described. The latter are stable in aqueous acetic acid under conditions which convert (8S)-8-hydroxyerythromycin B-6,9;9,11-acetal into (8S)-8-hydroxyerythromycin B.

Acetates↗
PubMed1978

Biotransformation of lankamycin, darcanolide, and 11-acetyllankolide by a blocked mutant of the erythromcyin producing organism Streptomyces erythreus.

The biotransformation of lankamycin and congeners darcanolide and 11-acetylankolide by a blocked mutant of the erythromycin-producing organism Streptomyces erythreus, which cannot synthesize erythromycin without supplementation with erythromycin precursors, was investigated. Darcanolide and 11-acetyllankolide were converted into the corresponding 15-deoxy-15-oxo derivatives. Lankamycin was transformed to 15-deoxy-15-oxolankamycin, 4''-deacetyl-15-deoxy-15-oxolankamycin and 3'-de-O-methylankamycin. None of the derivatives possessed high antimicrobial activity.

Anti-Bacterial Agents↗