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Biomedical subjects

G Sager

Publications and source records attributed to G Sager.

At least 109 records · Page 6Linked to original sources
PubMed1985

[Relations of standing height, sitting height and weight of male Americans].

Based on log/log graphs correlating weight with standing and sitting height of U.S. Americans as given by Altman and Dittmer (1962) allometric relations between both heights are tested and found to give relatively good results. With lacking dates of age the standing and sitting heights can only be put in loose time junction by comparison with the length/age tables of Maaser (1974). Approximate relations can be gained between the log weight and standing or sitting height respectively by following a method set up and applied by the author (Sager 1981a, b) with good success.

Age Factors↗
PubMed1985

[Mathematical treatment of a growth series for body mass in turkeys (male, female)].

Body weight values for 60 gobblers and 60 hens of 3 series of the turkey (Meleagris gallopavo silvestris) after data from Johnson (1953), Mosby and Handley (1943) are submitted to nonlinear regressions for selected functions of organismic growth. The results are compiled in 3 tables confronting natural with approximated and smoothed values. The tables imply the parameters of the growth functions and characteristical data as well as the amounts of deviations. Graphs show the body weight development for both sexes and the growth increase. The ratio of the amounts of body weight in the inflexion point to the theoretical final values ranges from 33 to 64% depending on the series and the growth function chosen.

Animals↗
PubMed1985

[Mathematical formulations of the fetal mass growth in cattle].

After a short review of investigations into fetal weight growth of cattle, the first mathematical treatment of values gained by Swett and collaborators (1948) and approximated by simple power functions after a proposal from Bereskin and Touchberry (1967) is recalled. Thereafter values for the weight of fetus and uterus with content as summarized by Huth (1962) are approximated with growth functions applying nonlinear regressions. The 6 functions taken into consideration range from classical to quite recent types. Results as listed in 2 tables show remarkable improvements. Parameters and an evaluation of 4 components of fetal development are added. Finally a comparison for the fetus of cattle and the domestic pig shows a lagging behind of cattle by temporarily about 20 percent in relative weight.

Animals↗
PubMed1985

[Length and weight growth of the Atlantic halibut (Hipoglossus hipoglossus male, female) off Norway according to Devold's data (1936)].

A short review on the behaviour and catching methods for the Atlantic halibut (Hippoglossus hippoglossus male, female) off Norway is given. Series of length and weight growth from 12 to 40 or 30 years of age respectively are submitted to nonlinear regressions in order to determine growth functions suited for optimal adaption. Results are presented in tables and graphs showing the extreme difference of development between the sexes. Finally the weight for age relation is determined in the allover conventional manner as well as for succeeding age groups confirming once more the sexual deviations.

Age Factors↗
PubMed1984

A comparison of the binding characteristics of the beta-adrenoceptor antagonists 3H-dihydroalprenolol and 125I-iodocyanopindolol in rat liver.

The binding characteristics of 3H-dihydroalprenolol and 125I-iodocyanopindolol have been compared in a particulate fraction from regenerating rat liver. When total 3H-dihydroalprenolol binding and inhibition of total 3H-dihydroalprenolol binding by (-)isoprenaline, (-)alprenolol and (+/-)cyanopindolol was investigated, it was found that all agents were bound to two classes of saturable binding sites. In the inhibition studies, the presence of two binding components was not obvious until the data were transformed into Hofstee plots and these were decomposed, except in the case of (+/-)cyanopindolol. Only (+/-)cyanopindolol was found to distinguish clearly between the two saturable binding sites identified by 3H-dihydroalprenolol, as indicated by a broad plateau in the inhibition curve. When 125I-iodocyanopindolol was used as radioligand, only one saturable binding site was identified, even in the presence of less selective inhibiting ligands. The lower affinity component of 3H-dihydroalprenolol binding could be inhibited by 10 microM phentolamine. However, binding experiments with 3H-prazosin indicated that the lower affinity component was not identical with the alpha-adrenoceptor. Phentolamine did not influence 125I-iodocyanopindolol binding. Thus, due to its higher specific activity and a high degree of selectivity, 125I-iodocyanopindolol appears to be the ligand of choice.

Adrenergic beta-Antagonists↗
PubMed1984

[Approximations of weight increase of the male and female Rattus norvegicus using Calhoun's (1952) data].

After a short review on weight series of rats and their approximation by rather different growth functions data from Calhoun (1952) are submitted to thorough investigations applying 14 functions altogether, 4 of which yield a definite growth time. The results for the best approximations are complied for the male and female in 2 tables together with the parameters as gained by nonlinear regressions and characteristic data of rat growth.

Age Factors↗
PubMed1984

[Seasonally modified forms of the revised Janoschek function].

Early attempts for modifying growth functions to annual variations dating back up to 2 decades are recalled together with examples for their application showing rather different degrees of approximation. In order to secure independence from special functions, Sager (1982) has proposed a general concept for the modification of growth functions. In this way, examples were treated with the Pütter-Bertalanffy's for crustaceans and clams, with the Gompertz' for the goby, and with the Richards' for the pollack - a near relative of the cod. In continuation of these endevours, the revised Janoschek's is presented in 2 forms, namely one adapted to birth data or in an unbound variant. Special attention is given to the evaluation of the parameters used in nonlinear regressions for both forms. The new equation for bound growth opens a chance for giving real birth values even in seasonally changing growth if one deciding parameter will surmount 1 as has been the case in many applications heretofore. As an example the mussel Mytilus edulis taken from marine "farms" in the Menai-Straits of North Wales is treated with the seasonally modified Janoschek function. Although the special case cannot be realized in this case, the curves for length growth and growth increase are rather instructive compared with the basic behaviour with lacking annual variations. Approximations from 0.5 to 2.7 a show very close agreement with natural values of length as can be verified from numerical and graphical displays.

Animals↗
PubMed1984

[Problems in the mathematical representation of mass growth in domestic chickens].

Mass growth of the domestic chicken as demonstrated for 2 races, namely the Rhode Island Red and the White Leghorn, gives rise to problems in mathematical representation. The reason is the rather deviating location of the inflexion point in the growth curve when compared with mammals. Most growth functions have been developed for animals reaching the inflexion point when about 1/3 or less of the final growth value has been reached as is mostly the case with mammals and fishes. Treating of domestic fowl, however, demands for possibilities of reflecting an inflexion point beyond the values of about 1/3 in the quotient Ww/W infinity as is shown by 2 series quoted by Parks from the Department of Animal Husbandry from the University of Sydney. Checking of the familiar growth functions leads to a rather critical result as almost all renowned functions fail to meet this demand. Besides the traditional logistic function with the rigid relation Ww/W infinity = 1/2, only few expressions for mass growth remain to cover the demands for fowl, among them the modified Janoschek with 0 less than Ww/W infinity less than (1-1/e) or less than 0.6321 respectively, and 2 formulations by Sager allowing for the total range 0 less than Ww/W infinity less than 1. Results are given in tables for 4 functions and in graphs for growth and growth increase for the best approximations with less than 25 g of mean single deviation.

Animals↗
PubMed1984

[Comparison of growth functions as exemplified by the southern smooth whale Eubalaena australis].

6 year's observations of the southern right whale in the San José Golf off Argentina by an American research team have yielded graphical growth curves. As the values are in good agreement with older results from 1908 to 1969 mathematical approximations are performed giving interesting results and allowing for a better insight into the properties of the growth functions applied. The different course of 3 functions as gained by nonlinear regressions is demonstrated by a graph. The results for 9 growth functions are combined in tables together with the values of the parameters and characteristic data.

Animals↗
PubMed1984

[Formation of mean values in growth spurts and incremental growth humps].

When averaging growth spurts and increase humps the question arises as to how much this procedure will affect the shape of the combined curves. It is shown that the frequency distribution is the main bar, reducing effects of disshaping . Examples for the growth spurts and humps show this influence in selected cases. Generally anxieties about unaccountable deformances can be cut down for the growth spurts and restricted for the increase humps.

Adolescent↗
PubMed1984

[Chest circumference of East German children in mathematical analysis].

Determinations of chest circumference for GDR children and youth in the years 1956 to 1958 as compiled by Marcusson and Oehmisch ( Marcusson 1961) are submitted to nonlinear regressions using a growth function proposed by the author. In addition the puberal growth spurt and growth velocities are calculated and represented in tables and graphs. Finally specific properties of growth development in chest circumference are confronted with those of the foot, tibia and radius as well as head circumference and body height. Possible changes due to acceleration will scarcely effect the latter considerations.

Adolescent↗
PubMed1983

Binding of theophylline in human serum determined by ultrafiltration and equilibrium dialysis.

1 Binding of theophylline (80 mumol/l) was determined in serum from healthy subjects by equilibrium dialysis and by ultrafiltration, using [3H]-theophylline, at 22 degrees C and at different pH-values. pH was regulated by gassing with CO2 or by dialysing the serum against a phosphate buffer before use. 2 Binding of theophylline in serum was 34-38% determined by equilibrium dialysis and 41-45% determined by ultrafiltration at pH 7.4-7.5. The protein concentration in serum decreased by 12-16% during equilibrium dialysis and increased by 20% during ultrafiltration. The intersubject variation in binding was small. 3 Binding of theophylline in serum was pH-dependent with 25-30% bound at pH 7.0 and 58-60% bound at pH 8.1-8.3. Binding was significantly correlated to the fraction of ionized theophylline. 4 The binding of theophylline in normal human serum is about 35-40% at pH 7.4 and 22 degrees C. The difference in binding observed between equilibrium dialysis and ultrafiltration may be explained by the opposite changes in protein concentration during the experiment. 5 Control of pH is necessary to obtain physiologically relevant data on drug binding in serum.

Adolescent↗
PubMed1983

[Formulation on the growth of the human tibia based on Gindhart's data (1976)].

Length data for the tibia as gained at the Fels Research Institute for the Study of Human Development and published by Gindhart (1976) are used for mathematical formulation following the method set up by the author for the representation of human length growth and recently applied to the radius development. The data for the tibia leave smaller room for the validity of the short term power function characteristic for younger age. Difficulties were encountered but overcome for the growth function proper (Sager 1981 a), whilst some uncertainties remain for the growth spurt of the female due to irregularities in the basic material.

Adolescent↗
PubMed1983

[Properties of harmonically season-modified Bertalanffy function of growth in length].

For individuals submitted to a moderate seasonal influence upon length growth the Bertalanffy function can be modified to show suppressed or stagnating growth as was already demonstrated by the author for nyctiphanes couchii (euphausiids) off the coast of Britanny (Sagér 1983a). In this paper the properties of the revised structure of the formula are shown implying the growth function proper and the increase function. Moreover the influence of a shifting birth date upon the growth behaviour is followed up leading to a catching-up phenomenon or growth compensation within 12 months when all factors acting on length development remain strictly periodic. Graphs for the modified function and its increase values are added for a given example.

Animals↗