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C M Swartz

Publications and source records attributed to C M Swartz.

At least 91 records · Page 5Linked to original sources
PubMed1988

Cell surface oligosaccharide modulation during differentiation: IV. Normal and transformed cell growth control.

In previous studies it was shown that cell surface oligosaccharide affinity class distributions and binding capacities were down-regulated as normal cells approach senescence. Using a sensitive, amplified, lectin/specific-ligand competition analysis three other growth regulation states were compared to that of cellular senescence. Non-senescent and senescent low-density and contact-induced growth inhibition was compared with neoplastic cell growth control. Non-senescent human fetal lung fibroblasts (IMR-90) down-regulated their mannosyl and galactosyl specificities in response to both low-density and contact-induced growth inhibition. Senescent IMR-90 down-regulate their mannosyl residues in response to contact conditions while they up-regulate their galactosyl residues under the same conditions. Growth-transformed transplantable canine glioma cells did not show density-dependent regulation of their cell surface oligosaccharide structures. Modulation of the CG cells with a specific alpha-mannosidase II inhibitor, Ricinus communis a galactosyl specific lectin, and pokeweed mitogen a cellular differentiating agent resulted in an altered growth phenotype and up-regulation of the mannosyl and galactosyl surface oligosaccharides. These data indicate a controller function for the cell surface oligosaccharides and a general influence on growth control.

Alkaloids↗
PubMed1987

Decreased epinephrine in familial alcoholism. Initial findings.

Stress-induced epinephrine release, measured in urine, was less in a group of 17 nonalcoholic adoptee probands, aged 18 to 36 years, with alcoholic biologic relatives than in 12 similar controls with no alcoholic relatives. This result is similar to previous observations of small stress-induced epinephrine release in humans with aggressive or hyperactive character traits. Resting epinephrine levels and epinephrine released by alcohol in soft drink were also lower in our probands than in controls. Familial alcoholism might be associated with a trait of globally decreased epinephrine responsiveness.

Adolescent↗
PubMed1987

Cell surface oligosaccharide modulation during differentiation. II. Membrane mobility of oligosaccharide lectin conjugates.

The quantitative, population doubling level (PDL) dependent changes in cell surface oligosaccharides on IMR-90 cells, were investigated from the perspective of membrane mobility of the lectin-oligosaccharide conjugates. Concanavalin-A (CON-A), wheat germ agglutinin (WGA), Ricinus communis agglutinin (RCA-120), and Dolichos biflorus agglutinin (DBA) were all observed to cluster, cap, and endocytose in cultured human diploid fibroblasts (IMR-90). Quantitative photometry at 37 degrees C over defined periods of time indicated that as the IMR-90s approached cellular senescence a specific lectin-dependent inability to either endocytose or process the capped complex occurred. The development of a biotin/avidin/enzyme amplification assay permitted the assignment of the accumulating signal to the internal compartment. Kinetic data indicate that there are at least three separate (and separable) mechanisms for the PDL related changes in lectin binding. Data for the CON-A complex indicates that at least two classes of functional complexes are present. Regression analysis of the kinetic data for the RCA-120 complex indicates a similar membrane clearance for the IMR-90s at all population doubling levels (PDL), suggesting that the quantitative differences observed earlier were due to simple quantitative reductions in the RCA complexing molecules. Data for WGA mobility on the membrane indicates that they are both changes in the number and mobility status of the complexes. These results indicate that the quantitative changes in lectin binding observed previously as IMR-90 cells approach senescence are correlated with alterations in membrane mobility patterns of the lectin oligosaccharide conjugates.

Cell Compartmentation↗
PubMed1987

Kinetic modeling of hormone release: application to time-averaged met-enkephalin release.

The time course of hormone concentrations in response to a stimulus can be characterized with kinetic methods to express rates of hormone release and elimination, total amount of hormone release and expected best times for blood sampling. Routine application of kinetic methods should increase the sensitivity and applicability of hormonal challenge tests. Applications to the TRH test and to prolactin release measurements are reviewed. A new kinetic model for continuously collected samples is applied to measurements of met-enkephalin release in rats. Calculations indicated an initial concentration of 1876 pg/ml and a ventricular volume of distribution of 0.25 ml. After exposure of rats to nitrous oxide, the rate of release of met-enkephalin-like activity into the ventricles rose from 3.4 to 8.3 pg/min.

Animals↗
PubMed1987

Low serum testosterone and myocardial infarction in geriatric male inpatients.

A survey of serum testosterone levels and a range of medical and behavioral factors was conducted on 71 males aged 46 to 89 years in an extended care medical facility. Histories of myocardial infarction or heavy drinking were separately associated with diminished testosterone levels (P less than .002 and P less than .006, respectively). No other factor was associated with testosterone level, including age and mobility. A testosterone level of no more than 438 ng/dl best discriminated patients with myocardial infarction (P less than .005, sensitivity 86.2%, and selectivity 50%). Increased incidence of myocardial infarction appeared to be influenced by testosterone in a threshold manner, since the incidence did not rise further with lesser testosterone levels once the level was below 438 ng/dl. The incidence of myocardial infarction among patients with testosterone levels below this threshold was unaffected by their exposure to alcohol. Among the 21 formerly heavy drinkers, many (62%) showed testosterone levels less than or equal to 300 ng/dl. Formerly heavy drinkers should be routinely considered for serum testosterone determination.

Age Factors↗
PubMed1987

Correction of lithium levels for dose and blood sampling times.

Inconsistencies inherent in the clinical application of morning serum lithium levels can be eliminated by correcting the levels for variations in dosage schedule, rate of lithium elimination, and blood sampling time. In this report, graphs constructed from an accurate pharmacokinetic model of lithium elimination are used to convert the serum lithium level into the daily exposure of the body to lithium. This method facilitates safety and effectiveness in lithium treatment and enables outpatient blood samples for lithium levels to be conveniently drawn in the afternoon.

Ambulatory Care↗
PubMed1986

Generalization of the effects of unilateral and bilateral ECT.

The correlation coefficients among four different measures of seizure duration (motor activity, EEG spikes, EEG total, tachycardia) were substantially lower with unilateral than bilateral ECT. This suggests that unilateral ECT is less well generalized through the brain than bilateral ECT.

Brain↗
PubMed1986

Characterization of the pituitary response in the TRH test by kinetic modeling.

Applying the principles of chemical kinetics to the time course of TSH concentrations after TRH infusion, individual values for total TSH release from the pituitary, TSH elimination and release rates, and latency for TSH release were found for 40 patients. Justification for using the observed peak TSH elevation as a consistent reflection of the total TSH release was provided by the high correlation between these two (r = 0.97, P less than 0.001). Kinetic modeling indicated that the most consistent reflection of total pituitary TSH response is the TSH elevation over baseline 35 min after TRH (with the peak expected 30 min post-TRH), rather than the area under the curve.

Humans↗
PubMed1984

Characterization and prediction of lithium blood levels and clearances.

Mathematical simulations and nonlinear numerical methods for characterizing the serum elimination half-life, volume of distribution, and renal clearance of lithium after multiple oral doses of lithium carbonate and two or more blood level determinations were constructed and adapted for clinical use. These characteristics were measured for 24 inpatients; predictions were made with the simulation and compared with actual succeeding blood levels. The average elimination half-life of 25.9 hours was compared with half-lives reported after single oral doses. Average and median errors of prediction were negligible; the root mean square error was 0.12 mEq/L, near the coefficient of variation of 0.082 mEq/L. The correlation between predicted and observed levels (r) was .82; a small systematic effect of weight was found.

Administration, Oral↗
PubMed1984

The treatment of tricyclic antidepressant overdose with repeated charcoal.

Activated charcoal given repeatedly through a nasogastric tube to three patients in coma from amitriptyline overdose greatly accelerated tricyclic elimination: the apparent half-life fell below 10 hours for each patient to as low as 4 hours. This contrasts with extended half-lives for amitriptyline elimination averaging 36.8 hours and regularly over 60 hours previously reported for overdoses treated without repeated charcoal. The enterohepatic recirculation of amitriptyline and nortriptyline appears to be a major influence on keeping their blood levels up. In one case, intravenous diazepam inhibited tricyclic elimination.

Adolescent↗