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Biomedical subjects

D Martin

Publications and source records attributed to D Martin.

At least 829 records · Page 46Linked to original sources
PubMed1975

Induction of endogenous murine C-type virus in spleen cell cultures treated with mitogens and 5-bromo-2'-deoxyuridine.

In short-term cultures of BALB/c spleen cells, treatment with a combination of 5-bromo-2'-deoxyuridine (BrdU) and either lipopolysaccharide W. Escherichia coli or concanavalin A resulted in release of C-type virus into the medium. Only lipopolysaccharide induced virus release when given alone. This could be potentiated by a combined treatment with BrdU. In contrast, phytohemagglutinin at mitogenic concentration had no effect with or without BrdU, suggesting that inducibility may vary between various mitogen-responsive spleen cell populations. In AKR mice, spontaneous virus release was detectable in nonstimulated spleen cell cultures. This could be potentiated by lipopolysaccharide, whereas no further increase occurred upon additional BrdU treatment. The induced viruses had C-type characteristics in that they contained reverse transcriptase that could be distinguished from cellular enzymes by template-primer preference experiments. Furthermore, the enzyme activities were particle-associated, banding in isopycnic sucrose gradients at 1.15-1.17 g/cm-3. The presence of C-type viruses was confirmed by electron microscopy.

Animals↗
PubMed1973

Auditory perception.

Auditory perceptual tasks involving the discrimination of fine differences in frequency, duration, or rhythmic pattern were given to a group of sixth form schoolboys. The results indicate that there is a wide range of auditory skills for different individuals, even within a relatively homogeneous group. There are also differences in a person's ability to carry out distinct tasks; there does not necessarily appear to be any correlation between his ability for each task.The findings support observations arising out of consideration of hearing problems in children and adults that pure tone threshold audiometry and its derivatives give an inadequate definition of hearing disorder and a limited understanding of the nature of hearing.

Adolescent↗
PubMed1973

Progressive systemic sclerosis. "Something old, something new, something borrowed, something blue".

These discussions are selected from the weekly staff conferences in the Department of Medicine, University of California, San Francisco. Taken from transcriptions, they are prepared by Drs. David W. Martin, Jr., Assistant Professor of Medicine, and Kenneth A. Woeber, Associate Professor of Medicine, under the direction of Dr. Lloyd H. Smith, Jr., Professor of Medicine and Chairman of the Department of Medicine. Requests for reprints should be sent to the Department of Medicine, University of California, San Francisco, CA 94143.

Age Factors↗
PubMed1972

Alterations in thyroid iodine release and the peripheral metabolism of thyroxine during acute falciparum malaria in man.

Previous studies of thyroid function during various infections have yielded conflicting results, but most have suggested an acceleration of peripheral thyroxine (T(4)) turnover during the acute infectious illness. In the present studies, thyroid function was examined by a method allowing simultaneous analysis of both endogenous thyroidal release and peripheral T(4) disposal in normal volunteers after induction of acute falciparum malaria. Subjects received iodide-(125)I, followed in 5-7 days by (131)I-T(4) intravenously. 4 days later, infection was induced by the injection of parasitized red blood cells. Bidaily measurements of serum protein-bound (125)I and protein-bound (131)I, and urinary (125)I and (131)I, together with frequent estimates of serum (127)I-T(4) (Murphy-Pattee) and free T(4) (FT(4)), were made during a control period, during acute illness, and during convalescence. Alterations in the peripheral metabolism of (131)I-T(4) during infection included significant decreases in the fractional disappearance rate for T(4) [(k)], and in the clearance and daily disposal of T(4), all of which returned to control values during convalescence. Total serum (127)I-T(4) increased late in the infected period to become greater during convalescence than either before or during infection, while FT(4) did not increase significantly until convalescence. An analysis of serum (131)I-T(4)/(127)I-T(4) and (131)I-T(4)/PB(125)I ratios confirmed these observations. The slope with time of ratios for urinary (125)I/(131)I, a reflection of thyroidal iodine release, was decreased during infection, but rebounded to control values during the convalescent period. The observed increments in serum (127)I-T(4) concentration in the convalescent phase may reflect in part the slowing of (k), but together with the rising ratios of urine (125)I/(131)I suggests enhanced thyroidal T(4) secretion immediately after the acute illness. Thus, with malarial infection, there appears to be an initial depression followed by a rebound in rates of thyroidal iodine release. In contradistinction to other infections, fractional turnover and daily disposal of hormone is decreased in malaria, perhaps due to hepatic dysfunction and the consequent impairment in cellular deiodinative processes.

Antimalarials↗