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Biomedical subjects

D Platt

Publications and source records attributed to D Platt.

At least 127 records · Page 7Linked to original sources
PubMed1987

[Pharmacokinetics and pharmacodynamics of theophylline in geriatric patients with multiple diseases].

The pharmacokinetics of theophylline (200 mg i.v.) were determined in 20 geriatric patients with multiple diseases. Serum concentrations were fitted to an open 2-compartment model. Percent changes in venous pCO2 and pO2 were used as parameters of the pharmacodynamic action. Total clearance was decreased and elimination half-life of theophylline was found to be prolonged in the elderly patients compared with data of a study with young healthy volunteers. The stronger the pharmacodynamic action of theophylline (percent change of venous pCO2 after 30 min), the faster was its elimination and the lower were measured concentrations after 2, 6, and 12 h.

Age Factors↗
PubMed1987

Ophthalmic surgical complications in Werner's syndrome: report on 18 eyes of nine patients.

In ten of 18 eyes from nine patients with Werner's syndrome cataract surgery was complicated by wound dehiscence and its consequences: peripheral anterior synechiae (4X), secondary epiretinal gliosis (4X), cystoid macular edema (3X) in the framework of Hruby-Irvine-Gass syndrome, unplanned filtering bleb (2X), and postoperative anterior ischemic optic neuropathy (1X). Additionally, corneal endothelial decompensation occurred in eight eyes. In view of the fibroblasts' reduced growth potential, we suggest small surgical incisions, extracapsular cataract surgery using phacoemulsification, intraocular irrigation solutions protecting corneal endothelium, nonabsorbable single knot sutures not removed before 1 year after surgery, and no local or systemic use of cortisone.

Adult↗
PubMed1986

Steroid receptor activation: the glucocorticoid receptor as a model system.

The glucocorticoid receptor has been used as a model for steroid receptor activation. Because of recent evidence for the essentially nuclear location of the unoccupied receptors of 1,25-dihydroxycholecalciferol and 17 beta-estradiol, the significance of the activation mechanism converting unactivated receptor complexes to DNA-binding forms is unclear for some receptors. Up to now the weight of evidence favors a cytoplasmic location of the unactivated glucocorticoid receptor. In this article we describe studies on the nature of the activation mechanism and of regulatory factors.

Animals↗
PubMed1986

Serum level, half-life and apparent volume of distribution of doxycycline in geriatric patients.

The serum level, half-life and apparent volume of distribution of doxycycline were determined in geriatric patients. The serum level and apparent volume of distribution were higher than those reported for younger persons. The apparent volume of distribution was correlated with the serum iron and beta-globulin levels. The possible influence of binding of doxycycline to serum iron on its pharmacokinetics is discussed.

Age Factors↗
PubMed1986

The effect of different fat supplemented diets on the erythrocyte ghosts and plasma lipid composition of geriatric subjects.

The responses of the lipid composition of erythrocyte ghosts and plasma phospholipid fatty acids of 20 female donors, aged older than 70 years, to different margarine and butter supplemented diets were investigated. On a low level of daily caloric intake (1900 kcal) there were no changes in phospholipid and cholesterol content of the red cell membranes, but statistically significant changes were found in erythrocyte and plasma phospholipid fatty acid patterns. These results demonstrate the influence of the fatty acid composition of the dietary fats with special reference to saturated, trans-isomeric monoene, and polyunsaturated acids.

Aged↗
PubMed1986

Plasma lipids and composition of red cells in four cases of Werner's syndrome.

Four cases of accelerated aging, known as Werner's syndrome (WS), are presented. Plasma lipid and lipoprotein findings and lipid compositions of red cell membranes are compared to those of old and young healthy people. Typical clinical findings, as reported in the literature, confirmed the diagnosis. Furthermore, an elevated osmotic fragility of red blood cells (RBC) was observed. RBC membranes of WS patients showed phospholipid concentrations similar to those found in people aged over 70 years, which have been reported to be lower than those of mature donors aged below 30 years. Fatty acid patterns of RBC membranes and plasma phospholipids were indicative of some disturbance in phospholipid subclass distributions in WS-patients.

Adult↗
PubMed1986

Pharmacokinetics and pharmacodynamics of furosemide in geriatric patients.

Twenty geriatric patients with multiple diseases were administered a single intravenous dose of 40 mg furosemide. Furosemide plasma and urine concentrations were measured using a thin-layer chromatography method and were fitted to an open 2-compartment model. Furosemide half-life was prolonged two-fold in the elderly patients compared with a control group of younger adults. In the same way renal clearance and total clearance were markedly reduced in the geriatric group. The non-renal clearance and the volume of distribution were not significantly altered. There were many significant correlations between clinical and biochemical data and pharmacokinetic parameters, especially between blood pressure and the area under the curve (AUC O-infinity), total clearance and non-renal clearance of furosemide. Our data suggest a special function of alpha-2-globulins in binding of furosemide. Renal function (i.e. creatinine clearance) was shown to be an important parameter for estimating the elimination rate of furosemide. In addition, pharmacodynamic action (volume of excreted urine) was closely correlated with the elimination rate: furosemide is apparently triggering its own elimination.

Aged↗
PubMed1986

Age-dependent phagocytosis of erythrocytes by the isolated perfused rat liver after galactosamine hepatitis and alpha-naphthylisothiocyanate cholestasis.

UNLABELLED: Isolated rat livers were perfused with an immunoglobulin-free fluid containing homologous rat erythrocytes suspended in an isotonic saline solution. Galactosamine hepatitis and alpha-naphthylisothiocyanate cholestasis were induced as experimental liver diseases. The glutamic oxalacetic transaminase (GOT) and guanosine triphosphate (GPT) activities, the potassium level as well as the redox quotients of lactate/pyruvate and beta-hydroxybutyrate/acetoacetate were determined as liver function parameters. RESULTS: The same dose of galactosamine led to two different types of reaction. The group suffering more damage (rendering maximum GOT activities) phagocytosed significantly (p less than or equal to 0.05) more erythrocytes than the other group. Galactosamine hepatitis significantly slows down the phagocytosis of erythrocytes. The function of the mononuclear phagocytosing cells in the liver is intact. The alpha-naphthylisothiocyanate (ANIT) cholestasis significantly reduces the capacity of the mononuclear phagocytosing cells in the liver. Young erythrocytes were phagocytosed significantly better than old ones in either type of liver damage, in galactosamine hepatitis and in ANIT cholestasis as well as by healthy livers.

1-Naphthylisothiocyanate↗
PubMed1986

[The effect of heparin, prednisolone and triamterene on the elimination of India ink by the reticulohistiocyte system of the isolated perfused rat liver].

The influence of heparin, prednisolone and triamterene on the elimination of colloidal carbon (India ink) by the reticulohistiocytary system of the isolated perfused rat liver was measured. The drugs were given directly to the perfusion medium. A significant reduction of the phagocytic capacity of Kupffer's cells for colloidal carbon under the influence of heparin, prednisolone and triamterene could be demonstrated.

Alanine Transaminase↗
PubMed1985

Methyl enol ethers as artefacts in capillary gas chromatographic profiles of aldehyde dimethyl acetals.

Methyl enol ethers are detected within the capillary gas chromatographic profiles of aldehyde dimethyl acetals derived from human red cell plasmalogens or from a synthetic aldehyde mixture. They arise from the dimethyl acetals via methanol elimination as artefacts of the injection technique. In a nutritional experiment, the probands showed a rising proportion of dimethyl acetals in the phospholipid fraction of their erythrocyte ghosts; this fact is seen as an effect of the lipid composition of the milk fat administered.

Acetals↗
PubMed1985

Phagocytosis of erythrocyte membranes (white ghosts) from different species by the isolated perfused rat liver.

Autologous and heterologous erythrocyte membranes (white ghosts) - suspended in a perfusion medium free of immunoglobulins, proteins and hemoglobin - were offered for phagocytosis to isolated perfused livers of different rat strains. The mononuclear phagocyte system of the liver was able to phagocytize these membranes without opsonization. An immunological reaction between Kupffer cells and red cell membranes cannot be excluded, since autologous cell membranes are phagocytized at a higher rate than heterologous cell membranes.

3-Hydroxybutyric Acid↗
PubMed1985

ABO blood group system, age, sex, risk factors and cardiac infarction.

In a retrospective study in 3100 patients of different ages the relationship between blood group and cardiac infarction was investigated in 450 patients. The patients were divided in two age groups: those who were 65 yr old and older and younger patients (age less than 65 yr). The predominance of blood group A in patients with cardiac infarction was highly significant in both age groups (P less than 0.005, two-tailed Chi-square test). Step-wise excluding all patients with at least one of the risk factors, hypertension, hyperuricemia, diabetes mellitus, smoking, and hyperlipemia similar results were found: the predominance of blood group A in the elderly patients with cardiac infarction was even higher than before excluding the risk factors (P less than 0.001). The predominance of blood group A was also demonstrated at a lower level in younger patients with cardiac infarction (P less than 0.05). Our investigation strongly suggests the existence of a genetic factor associated with blood group A and independent of the other risk factors which is also responsible for a greater incidence of cardiac infarction.

ABO Blood-Group System↗
PubMed1985

Aging in vivo and neuraminidase treatment of rat erythrocytes and their sequestration by the isolated perfused rat liver.

The isolated perfused rat liver as a model for phagocytosis leaves the specific arrangement of macrophages in the original tissue structure intact. Therefore phagocytosis may occur under terms closely approaching physiological conditions. Separation of rat erythrocytes according to their density in 13% young, 75% mature and 12% old cells permits the establishment of differences in the mean cellular volume (MCV), mean cellular hemoglobin concentration (MCHC) and content of N-acetylneuraminic acid per red blood cell (NANA/RBC). Perfusion of these fractions does not result in significant differences of sequestration of the isolated liver. Enzymatic release of 90% of membrane-bound sialic acid causes a significant increase of 20% in the elimination of erythrocytes from the perfusate. Treatment with neuraminidase is a trigger for sequestration either by adherence or by complete phagocytosis. Incubation of neuraminidase-treated erythrocytes with plasma does not increase the removal rate of cells during perfusion.

Animals↗