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Biomedical subjects

S C Olson

Publications and source records attributed to S C Olson.

60 records · Page 4Linked to original sources
PubMed1986

Cortical atrophy in young adults with a history of hyperactivity in childhood.

A computed tomographic (CT) brain scan study was conducted in 24 young males treated and followed up for hyperactivity since childhood. Compared to 27 matched controls, adults with a history of hyperactivity had a significantly greater frequency of cerebral atrophy. No differences in cerebellar atrophy frequency or in lateral cerebral ventricle-to-brain ratio (VBR) were found. The possible associations of hyperactivity or perhaps stimulant drug treatment to atrophic brain changes are discussed.

Adult↗
PubMed1986

Pharmacologic approaches to psychogenic polydipsia: case reports.

Psychiatric patients presenting with chronic psychogenic polydipsia are often difficult to treat with standard psychiatric interventions. Pharmacologic intervention was attempted in three patients and was successful in one. One patient had a significant and sustained reduction of water intake while on 160 mg of propranolol. One patient did not improve with either propranolol or captopril while a third patient showed no improvement of serum sodium with demeclocycline nor reduction of water intake with propranolol. The potential mechanisms by which these pharmacologic agents might alter thirst in patients with primary polydipsia are discussed.

Adult↗
PubMed1985

Effect of food and tablet age on relative bioavailability and pharmacodynamics of two tolbutamide products.

Relative bioavailability and pharmacodynamics of tolbutamide from two different commercially available tablet products have been evaluated in healthy subjects in a single-dose crossover study. "Fresh" tablets and tablets aged by exposure to 98% relative humidity for 3 d at ambient temperature were studied. Aging was found to differentially affect both the rate and extent of absorption for the two products. Differences were reflected by log AUC (generic product AUC 10% lower than the product of the innovator, p = 0.047), peak concentration (generic product 27% lower than the product of the innovator, p = 0.0001), mean absorption time (generic product 119% longer than the product of the innovator, p = 0.0008), and mean residence time (generic product 17% longer than the product of the innovator, p = 0.011). Aged product from the innovator produced statistically significantly higher serum tolbutamide concentrations for the first 8 h postdose and a greater glucose depression than aged generic product. Administration of unaged tablets with food produced differences in the rate of absorption, manifested in time-to-peak (generic product 69% later than the product of the innovator, p = 0.006), peak concentration (generic product 18% lower than the product of the innovator, p = 0.001), and mean absorption time (generic product 104% greater than the product of the innovator, p = 0.007), which resulted in statistically significantly higher tolbutamide concentrations for the product of the innovator than for the generic product for the first 3 h postdose.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

1-O-alkyl-2-arachidonoyl-sn-glycero-3-phosphocholine. A common source of platelet-activating factor and arachidonate in human polymorphonuclear leukocytes.

1-O-[3H]Alkyl-2-lyso-sn-glycero-3-phosphocholine (1-O-[3H]alkyl-2-lyso-GPC) incubated with human polymorphonuclear leukocytes (PMN) for 30 min is metabolized to 1-O-alkyl-2-acyl-GPC containing greater than 80% arachidonate at the 2 position (Chilton, F. H., O'Flaherty, J. T., Ellis, J. M., Swendsen, C. L., and Wykle, R. L. (1983) J. Biol. Chem. 258, 7268-7271). PMN containing 1-O-[3H]alkyl-2-arachidonoyl-GPC incorporated into their cellular phospholipids in this manner were stimulated with Ca2+ ionophore (A23187). Within 5 min after stimulation, 14%, 7%, and 7% of the total 1-O-[3H]alkyl-2-arachidonoyl-GPC in the cells had been converted to 1-O-[3H]alkyl-2-acetyl-GPC (platelet-activating factor), 1-O-[3H]alkyl-2-lyso-GPC, and 3H-labeled neutral lipid, respectively. Stimulation by opsonized zymosan yielded similar results. In related studies, cells were labeled with 1-O-hexadecyl-2-arachidonoyl-GPC containing a [methyl-14C] choline moiety. The nature of the long-chain acyl residues in the sn-2 position of the labeled 1-O-hexadecyl-2-acyl-GPC remaining after stimulation with A23187 was examined. Analysis by high-performance liquid chromatography using synthetic 1-O-hexadecyl-2-acyl-GPC standards indicated there is a time-dependent loss of arachidonate from the 2 position of the labeled 1-O-hexadecyl-2-arachidonoyl-GPC followed by reacylation by other fatty acids (primarily linoleic and oleic). This shift in the acylation pattern exhibited after Ca2+ ionophore stimulation was further examined in PMN preincubated with A23187 and subsequently incubated with labeled 1-O-alkyl-2-lyso-GPC; the stimulated cells produced 1-O-[3H]alkyl-2-acetyl-GPC (greater than 15% of total label) and 1-O-[3H]alkyl-2-acyl-GPC containing linoleic acid and oleic acid, rather than arachidonic acid in the sn-2 position. The findings demonstrate that upon stimulation of PMN, 1-O-alkyl-2-arachidonoyl-GPC can yield arachidonate and 1-O-alkyl-2-lyso-GPC; the 1-O-alkyl-2-lyso-GPC formed may be acetylated producing platelet-activating factor or reacylated with fatty acyl residues other than arachidonate.

Arachidonic Acid↗
PubMedDate not supplied

Midsagittal cerebral anatomy by magnetic resonance imaging. The importance of slice position and thickness.

Several recent studies of psychiatric patients have relied upon magnetic resonance imaging (MRI) to demonstrate features of cerebral anatomy in the midsagittal plane. Methodologies have varied somewhat in relation to thickness and position of planes of view. Due to concerns over the effects of slice thickness and position on measurements, the authors used a multislice thin plane method to assess these effects in 143 individuals (34 controls, 58 schizophrenics, and 51 with bipolar or schizoaffective disorder). Substantial variance in area measurements attributable to slice position emerged, especially in ventricular, cerebral and cerebellar area. Of greater importance would be the demonstrated interaction of position with diagnosis and sex in measures of several regions. The implications of these findings for MRI studies are discussed.

Adult↗