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Biomedical subjects

L Brown

Publications and source records attributed to L Brown.

At least 19 recordsLinked to original sources
PubMed1979

Cardenolide analogues: 10--characterization of cardiac glycosides by chemical ionization mass spectrometry.

The potential of chemical ionization mass spectrometry for the characterization of naturally occurring and semi-synthetic cardiac glycosides has been investigated. Methane, isobutane and ammonia were used as reactant gases. With the exception of ouabain, the ammonia chemical ionization mass spectra of the cardiac glycosides examined in this work contained abundant [M + NH4]+ions and abundant fragment ions formed by cleavage of glycoside bonds. Ammonia chemical ionization mass spectrometry was found to provide a rapid and sensitive method for the characterization of the products of glycosidation reactions. In contrast, the methane and isobutane chemical ionization mass spectra of the cardiac glycosides, with the exception of ouabain, did not contain protonated molecular ions and did not contain abundant fragment ions above m/z 400.

Ammonia↗
PubMed1979

Potentiation of neuromuscular weakness in infant botulism by aminoglycosides.

A retrospective study of ten patients with infant botulism who received gentamicin or kanamycin suggests that aminoglycoside antibiotics potentiate muscular weakness and precipitate respiratory failure as late as 27 days after onset of the disease. Although it is difficult to separate progression of the disease from the effects of antibiotics, the rapidity of deterioration following aminoglycoside treatment and the rapidity of recovery following cessation of aminoglycoside therapy is highly suggestive. A review of five patients who received only penicillin or a semisynthetic derivative of penicillin did not reveal any temporal deterioration with onset of penicillin therapy or improvement with cessation of penicillin therapy.

Ampicillin↗
PubMed1978

Anatomical correlates of electrical and behavioral events related to amygdaloid kindling.

Anatomical structures demonstrating increased glucose uptake during the various stages of amygdaloid kindling in rats were identified by the 14C-2-deoxyglucose (DG) autoradiographic technique. Partial (stages 1 and 2) seizures were correlated with increased DG uptake in the ipsilateral amygdala and its direct projection fields. The appearance of generalized motor (stages 3,4, and 5) seizures was accompanied by less limbic involvement and recruitment of a bilateral system including substantia nigra, specific and nonspecific thalamic nuclei, globus pallidus, and neocortex. Increased hippocampal DG uptake was correlated with prolonged amygdaloid after discharge duration but not with the behavioral seizure stage. This study does not reveal which of these structures are responsible for the observed behavioral and electrical events and which are activated by them. It does suggest, however, that three discrete anatomical systems underlie the generation of partial seizures, generalized motor seizures, and local after discharge.

Amygdala↗
PubMed1978

Computed tomography in meningitis.

Computed tomography in 34 cases of meningitis has revealed a spectrum of findings. In acute cases these include enlargement of the subarachnoid spaces, generalized contrast enhancement of the meninges and ependyma, sterile and pyogenic subdural collections, cortical infarction, and cerebral necrosis.

Age Factors↗
PubMed1978

Plasma membrane associated metabolic parameters and the aging of human diploid fibroblasts.

Substrate uptake, portions of the cyclic AMP system, membrane fluidity and cellular phospholipid content are some of the parameters which are structurally associated with the plasma membrane and which have been linked to the control of cell proliferation. These parameters were studied with respect to cellular aging of human embryo lung fibroblasts (HELF) in culture. We observed in late passage an increase in the rate of uridine transport and in cellular cyclic AMP levels. These results were examined in relation to the increase in cell volume which occurs in senescing HELF. We also observed an increase in Vmax of uridine transport, and a decrease in the Km of cyclic AMP phosphodiesterase (PDE) as quiescent, passage 18-25, HELF were stimulated to divide with fresh serum. A similar effect of serum occurred in late passage (p. 43) cells despite the inability of these late passage cultures to undergo further proliferation. There was no change in cAMP-PDE activity with increasing passage number suggesting that the observed alterations of the cAMP levels, basal and in response to extracellular effectors, were due to alterations in the adenyl cyclase system. We observed no change in senescent HELF in membrane fluidity or phospholipid and neutral fat content.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1978

"Ghost" forms of Giardia lamblia cysts initially misdiagnosed as Isospora.

Because of their distinctive morphology the cysts of Giardia lamblia usually are not mistaken for cysts or eggs of other intestinal parasites. At a hospital laboratory in Kentucky a case of giardiasis was encountered in which the initial fecal examination revealed only degenerated cysts of Giardia which were mistaken for the oocysts of Isospora at the one-sporoblast stage.

Adult↗
PubMed1977

Tuberculosis bacteriologic reliability. Sputum specimens submitted by mail.

The reliability of examining mailed specimens of sputum for tubercle bacilli was studied by dividing 132 sputum specimens. One half of each specimen was examined on the same day as collection (fresh); the other half was examined after a delay of from one to eight days (mailed). There were a few discrepancies, but no advantage was shown for use of the fresh portion of the specimens. The rate of contamination was slightly greater in the mailed portions (6.6%).

Culture Media↗
PubMed1977

Health expenditure.

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Health Expenditures↗