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G Sager

Publications and source records attributed to G Sager.

At least 73 records · Page 4Linked to original sources
PubMed1990

Effects of insulin on human beta-adrenoceptors.

The effect of insulin on beta-adrenoceptor stimulation and binding in mononuclear leucocytes from healthy subjects was studied. After 1 min exposure to insulin, the sensitivity and maximum response to (-)-isoprenaline and the number of beta-adrenoceptors increased. After 35 min exposure to insulin, the sensitivity and maximal response to (-)-isoprenaline stimulation were lower than the pretreatment values. The beta-adrenoceptor density was similar to the control value after 35 min exposure to insulin. The present observations may account for some of the cardiovascular effects of insulin.

Adult↗
PubMed1990

[The capillarization of the M. pectoralis of the turkey (Meleagris gallopavo) from hatching to the 280th day of life].

The capillarization of the M. pectoralis was examined in the turkey as it changed with age. Examined was the density of the muscles fibers (per mm2), the density of the capillaries (per mm2) and the quotient muscle fibers/capillaries. In accordance with the sequence of the original data four functions of organismic growth (slightly altered) were utilized for the approximation of the data for descending amounts: Pütter/Bertalanffy (1920, 1934); Richards (1959); Janoschek enlarged after Sager (1980) and Richards enlarged after Sager (1980). The approximations were made via nonlinear regressions, whereby the sum of the error amounts and the sums of the error squares served as criteria of quality. The results including the deduced initial and end amounts are combined in tables which also contain the parameter of the way the computations were conducted.

Aging↗
PubMed1990

[Age characteristics of the normal human skeletal musculature--mathematical description of postnatal skeletal muscle growth].

The number of muscle fibres per mm2 is age dependent, and therefore briefly denoted as age specific number (Alterskennzahl AK). We determined the AKs for the age groups up to 25 years, separated after the sexes and for M. vastus lateralis et deltoideus. According to the trend of the original data the approximations have been carried out applying 4 functions of organismic growth in modified form, i.e. the Pütter (1920), Bertalanffy (1934), Richards (1959), Janoschek extended by Sager (1984) and Richards extended after Sager (1980). Curve fitting is reached by regression analysis and nonlinear regressions using the sums of the linear deviations as a criterion for the goodness of fit. Results including initial as well as final values are summarized in tables with the parameters of the calculation methods added. The AKs allow judging the degree of maturity in the skeletal musculature during childhood. Transposing of the equations for AK = W yields t as a function of the normally adjunctive age specific number. The difference against real age reveals to which degree the musculature is eventually underdeveloped. Concerning the interpretation the fact should be kept in mind that biological processes are involved. The relation of the fibre types too implies a characteristic age dependency. This statement and the fibre diameters gained from the same material allow a mutual control and an exact fixation in each case.

Adolescent↗
PubMed1989

Growth, differentiation and the beta-adrenergic signal system of HL-60 cells. Characterization in a medium with insulin as the only added protein.

The purpose of the present investigation was to define experimental conditions for studies on growth, differentiation and the beta-adrenergic signal system of HL-60 cells. The cell medium was completely devoid of added proteins and hormones other than insulin. The HL-60 cell was able to grow and differentiate in this medium. The spontaneous differentiation along the granulocytic pathway after 72 hr, as assessed by the Nitro Blue tetrazolium test, increased by 400% compared to the serum supplemented medium, but the response to 1 microM retinoic acid was equal in the two media. Induction of monocytic differentiation by 0.16 microM phorbol-13-acetate-12-myristate, as determined by surface adherence after 24 hr, was lower in the absence than in the presence of serum. cAMP levels were elevated in response to (-)-isoproterenol. The EC50 was 0.36 +/- 0.01 microM (mean +/- SE, N = 3). The beta-adrenergic ligand 3H-CGP 12177 was specifically bound to 1 single class of binding sites (Kd: 0.15 +/- 0.04 nM, Bmax: 2220 +/- 150, mean +/- SE, N = 3). These data are comparable to our previously reported findings in serum supplemented medium. The present data show that HL-60 cells are able to grow and differentiate in the absence of serum proteins and hormones other than insulin. Under the present experimental conditions, these cells possessed functional beta-adrenergic receptors.

Binding Sites↗
PubMed1989

The effect of the plasticizers TBEP (tris-(2-butoxyethyl)-phosphate) and DEHP (di-(2-ethylhexyl)-phthalate) on beta-adrenergic ligand binding to alpha 1-acid glycoprotein and mononuclear leukocytes.

The plasticizers tris-(2-butoxyethyl)-phosphate (TBEP) and di-(2-ethylhexyl)-phthalate (DEHP) and the beta-adrenergic receptor-blockers [3H]-(-)-dihydroalprenolol ([3H]-(-)-DHA) and [3H]-(-)-CGP 12177 were tested for their ability to interact with beta-adrenergic binding to alpha 1-acid glycoprotein (AAG) and mononuclear leukocytes (MNL). The IC50-values, obtained by displacement of [3H]-(-)-DHA bound to AAG, were 3.5 nM, 2 microM and 4 microM for TBEP, (-)-alprenolol and DEHP, respectively. (+/-)-CGP 12177 had virtually no effect on radioligand binding to AAG. The [3H]-(-)-CGP 12177 binding to MNL consisted of beta-adrenergic receptor binding (Kd = 210 pM) and non-saturable binding. [3H]-(-)-DHA was bound to two different classes of binding sites on MNL, the beta-adrenergic receptors (Kd = 440 pM) and a secondary class of binding sites (Kd = 64 nM). (+/-)-CGP 12177 displaced about 30% of [3H]-(-)-DHA from MNL with an IC50-value of 190 pm. (-)-ALP displaced about 85% of total bound radioligand and gave a biphasic displacement curve with IC50-values of 320 pM and 690 mM, respectively. TBEP displaced a considerable fraction of [3H]-(-)-CGP 12177 and [3H]-(-)-DHA bound to MNL beta-adrenergic receptors, whereas DEHP had no effect. In contrast, DEHP caused displacement of [3H]-(-)-DHA from the MNL low affinity sites, but was a markedly less potent displacer compared to TBEP. The present study shows that TBEP and DEHP interact with beta-adrenergic transport proteins, non-specific tissue binding sites and beta-adrenergic receptors coupled to adenylate cyclase. Plasticizers may thus affect the biology and pharmacology of the beta-adrenergic signal system.

Adult↗
PubMed1989

Binding of prazosin and propranolol at variable alpha 1-acid glycoprotein and albumin concentrations.

1. The effect of variable alpha 1-acid glycoprotein (AAG) and albumin (HSA) concentrations on the binding of prazosin and propranolol was assessed in plasma after surgery and in mixtures of AAG/HSA with concentrations mimicking those found in vivo. 2. On the pre-operative day the binding of prazosin and propranolol was 94.8% and 89.0%, respectively and 97.3% and 93.2%, respectively, 5 days after surgery. 3. In solutions containing mixtures of highly purified AAG and HSA representing the pre-operative state, 88.6% and 83.9% binding of prazosin and propranolol was observed, whereas for solutions mimicking post-operative plasma, the equivalent values were 94.6% and 91.4%, respectively. 4. The ratios between bound and unbound concentrations of both drugs were closely correlated to the concentrations of AAG, but not to the concentrations of HSA. 5. The present study demonstrates that AAG is responsible for the binding variability of prazosin and propranolol in plasma from post-operative patients.

Aged↗
PubMed1989

Binding of prazosin to alpha 1-acid glycoprotein and albumin: effect of protein purity and concentrations.

Prazosin is extensively bound in human serum/plasma. In the present study a bound fraction of 93-95% was observed at 37 degrees for therapeutic drug concentrations. Both alpha 1-acid glycoprotein (AAG) and albumin (HSA) are established as transport proteins for prazosin, but their individual contribution to the extent and variability of protein binding in serum/plasma is unclear. The present study showed that AAG possesses one binding site per molecule with high affinity (Kd approximately 0.8 microM) for prazosin. HSA, essentially globulin-free, bound prazosin with lower affinity (Kd approximately 30 microM) with an average of 0.3 binding sites per molecule. However, less purified HSA, containing globulins, exhibited apparently higher affinity (Kd approximately 8 microM), but lower binding capacity (0.07 sites per molecule) for prazosin. In mixtures of highly purified proteins, the concentrations of AAG, and not HSA, determined the extent and variability of prazosin binding.

Dialysis↗
PubMed1989

Tumoral calcinosis. Case presentation and review.

Tumoral calcinosis is a disease of unknown etiology with a greater prevalence among blacks, in which subcutaneous calcifications are found around the extensor surface of the hip, shoulder, hand and occasionally the knee. They must be differentiated from other more common causes of calcification.

Aged↗
PubMed1988

Interactions with the protein binding of 7-hydroxy-methotrexate in human serum in vitro.

7-Hydroxy-methotrexate (7-OH-MTX), the major extracellular methotrexate (MTX) metabolite, is 90-95% bound in human serum, with albumin (HSA) as the major binding protein. Reports of an interaction with concomitantly administered non-steroidal antiinflammatory drugs (NSAIDs) during MTX therapy led us to investigate whether these compounds could reduce the binding of 7-OH-MTX in vitro. Equilibrium dialysis experiments demonstrated that naproxen and indomethacin concentration dependently reduced the binding of 1 microM 7-OH-MTX. After ingestion of 1000 mg naproxen, per cent unbound 7-OH-MTX in sera from volunteers increased 2-3-fold in vitro, positively correlated to naproxen concentrations (P less than 0.00015). In addition, etacrynic acid, bilirubin, sulphamethizole and acetylsalicylic acid displaced 7-OH-MTX from its binding protein(s) in a competitive manner. The data suggest that 7-OH-MTX interacts with several exogenous and endogenous substances associated with HSA in human serum. Displacement of 7-OH-MTX from HSA may contribute to the interaction between NSAIDs and MTX.

Adult↗
PubMed1988

The human promyelocytic leukemia cell (HL-60 cell) beta-adrenergic receptor.

We have characterized the beta-adrenergic receptor binding site and the beta-adrenergic cAMP response of the HL-60 cell. The hydrophilic ligand [3H]-(-)-CGP-12177 was specifically and reversibly bound to one single class of binding sites (Kd 220 pM and Bmax 1,970 sites/cell). The adrenergic agonists inhibited the specific radioligand binding. The order of potency was isoproterenol greater than epinephrine greater than norepinephrine. The beta-2 selective antagonist ICI 118551 had a binding affinity 3 orders of potency higher than the beta-1 selective antagonist, atenolol. The adrenergic agonists elevated the cAMP accumulation in a concentration-dependent mode. The order of potency was isoproterenol greater than epinephrine greater than norepinephrine. Both the binding and the functional studies revealed stereospecificity and reversibility. The present data show that HL-60 cells possess beta-2 adrenergic receptors functionally coupled to adenylate cyclase.

Cyclic AMP↗
PubMed1988

Catecholamine binding and concentrations in acute phase plasma after surgery.

The present study was undertaken to decide whether the bound fractions and/or total concentrations of catecholamines were determinative for the variability of biologically active concentrations in human plasma. The binding and concentrations of noradrenaline (NA) and adrenalin (Adr) were determined in acute phase plasma after major hip surgery in five subjects. The bound fractions before surgery were 23.0% and 18.4% for NA and Adr, respectively. The binding of catecholamines increased in the post-operative period. Five days after surgery the binding of NA and Adr was 30.9% and 24.0%, respectively. The surgical trauma induced an acute phase reaction in plasma with a decrease of albumin (HSA) concentrations whereas the concentrations of alpha-1 acid glycoprotein (AAG) increased. The catecholamine concentrations showed a considerable inter- and intraindividual variability. However, the present work shows that the variability of the biologically active catecholamine concentrations is mainly dependent on the total plasma concentrations and not the plasma protein binding.

Acute-Phase Reaction↗
PubMed1988

Elevated level of beta-adrenoceptors in intact hepatocytes from partially hepatectomized rats.

The binding characteristics of 125I-iodocyanopindolol (125I-ICYP) and 3H-CGP-12177 to intact hepatocytes and a particulate fraction prepared from hepatocytes from sham-operated and partially hepatectomized rats were compared. In the particulate fraction, the beta-adrenoceptor number increased 4-10-fold after partial hepatectomy. 125I-ICYP binding to intact cells demonstrated a high fraction of non-specific binding, although phentolamine was included in the assay to reduce non-specific binding. 3H-CGP-12177 binding to intact cells also demonstrated a higher fraction of non-specific binding than in most cell types. In intact cells, the beta-adrenoceptor number increased 5-6-fold after partial hepatectomy. The number of receptors was comparable in intact cells and the broken cell preparation, indicating that receptors are conserved during the preparation of the particulate fraction.

Adrenergic beta-Antagonists↗
PubMed1988

Distribution of 7-hydroxymethotrexate in human blood.

We have examined the in-vitro distribution of 7-hydroxymethotrexate (7-OH-MTX), a cytotoxic metabolite of methotrexate (MTX), in human blood, and its protein binding in serum. The distribution of 7-OH-MTX (10(-6) M) in fresh samples of whole blood was studied at 37 degrees C and pH 7.51 +/- 0.05 (mean +/- s.d.), and its protein binding was assessed by equilibrium dialysis of serum against Krebs Ringer phosphate buffer at 37 degrees C and pH 7.41 +/- 0.07 (mean +/- s.d.). 7-OH-MTX had a mean cell/plasma concentration ratio of 0.03 (range 0-0.27, n = 18). It was extensively bound in human serum, with a bound fraction of 90.4 +/- 3.3% (mean +/- s.d.) in healthy volunteers (n = 11), and significantly lower, 82.3 +/- 4.0% (mean +/- s.d.), in hypoalbuminaemic surgical patients (n = 7). The binding of 7-OH-MTX was correlated with serum albumin (HSA) concentrations (r = 0.72, P less than 0.0007, n = 18). Blood distribution data support the contention that 7-OH-MTX has a small volume of distribution, and HSA appears to be mainly responsible for the high degree of its protein binding in serum.

Adult↗
PubMed1988

[Gathering measurement data of human growth in height].

After a short review of 2 centuries' measurements in human body height and the growing effectivity of acceleration, the problems in gaining and processing of the data are considered. Among these there are the methods of measurement, selection of adequate personnel, influence of the time of day, and of seasons, transition from supine length to standing height at about 2 years of age, converting of the datum to chronological age etc. Difficulties in treating different sequences and length intervals of measurements are explained by 2 examples, namely a supposed parabolic course of the growth curve for a shorter interval and a growth specific course from the postnatal phase until pubescence. The influence of the factors mentioned is expressed in tables resulting from specially developed formulae for interpolation. Further considerations concern the adaptation of measurements at ad hoc times to values for full, half, and quarterly years of chronological age. As graphical representations for percentiles of body height cannot meet this requirement, numerical data after Tanner et al. for British children have been used in the form of relative values. All contemplations in this contribution should be taken as recommendations to give anthropometrists a basis for further reflections.

Body Height↗
PubMed1988

[Definition and application of 8 anthropologic indices].

Quite recently, the existing 3 indices for the evaluation of human body constitution in adults have been supplemented by 5 further ones proposed by Komenda of the Institute of Medical Biophysics and Nuclear Medicine of the Palacký University of Olomouc, CSSR. This gives rise to considerations and comparisons of the now 8 indices the definitions of which are presented first. In contrast to the indices by Quetelet-Bouchard, Quetelet-Kaup-Gould and Rohrer-Buffon-Bardeen combining body weight W and a power of body height L, the Komenda group of indices comprises either interrelations of weight and chest circumference U or of all 3 somatic seizes. For reason of adequate interpretation, the transfer from chest circumference to chest cross-section of the elliptical against a circular form is investigated and assured. Thereafter, the range of application is extended to the whole process of development from birth to adulthood, using growth series of L, U, and W as given by Marcusson and Oehmisch and treated with growth specific approximations after models of Sager. As a result tables and graphs for the improved somatic values and the course of the 8 indices are given complemented by the U/L-curves for males and females.

Adult↗