Biomedical subjects

J Peil

Publications and source records attributed to J Peil.

At least 37 records · Page 2Linked to original sources

PubMed1986

[Age dependent changes in the collagen content of the human oviduct].

On the basis of present investigations, namely on account of the hydroxyproline determinations and the biomathematical analysis of data, the ageing of the human Fallopian tube with regard to its collagen content can be characterized as follows: Collagen concentration of the oviduct increases slightly and almost linearly up to the 5th decade of woman life. In the 2nd half of the fifth decade, i.e. already in the premenopausal years, this increase is accelerated, then changing into a yet almost linear but stronger rise of the collagen content.

Adult↗

PubMed1986

[Thyroid reactions in Wistar rats during the circadian rhythm after ganglionectomy at normal temperature and under cold exposure with regard to the influence of the epiphysis cerebri].

Serum thyroxin (T4), serum TSH, and pituitary TSH were measured by radioimmunoassay (RIA) and serum cholesterol by Liebermann-Burchard reaction in rats 4 times a day (light-dark cycle: 14 L: 10 D) after gangliectomy (bilateral extirpation of the Ganglia cervicalia superiora) at cold and normal temperature conditions. 80 male Wistar rats were divided into 4 groups: sham-operated group, 24 degrees C (297 K); sham-operated group, 10 degrees C (283 K); gangliectomy, 24 degrees C (297 K), and gangliectomy, 10 degrees C (283 K). We have sacrificed the rats 30 d after operations at the following day-times: middle light, middle darkness, 1 h after light "on" and 1 h after light "off" (they were exposed to cold 72 h before killing). It was found that gangliectomy significantly depressed blood level of thyroxin. On the other hand, it enhanced the serum cholesterol and TSH levels as well as the pituitary TSH content. Exposure to cold increased thyroxin, serum TSH and pituitary TSH. The cholesterol level, however, was significantly decreased. Gangliectomy causes a reduction of the cold-induced stimulation of thyroxin (significant), serum TSH, and pituitary TSH content (significant). The cholesterol (in relation to the cold-exposure alone) was significantly increased under these conditions. We have found similar results in another long-time experiment (90 d exposure) after gangliectomy as well as after pinealectomy. There also appears a lowered thyroxin and an increased cholesterol level (in dependency on the seasons). Gangliectomy induced a decrease of the pineal weight and a compensatory thyroid growth. Exposure to cold induced an increase of pituitary and pineal weights. Gangliectomy provokes a reduction of the cold-induced augmentation of the pineal weight. The results indicate that gangliectomy diminishes the total levels of circulating T4 in the presence of an intact pineal gland and reduces the cold-induced increase of T4 in long-time experiments (30 and 90 d post operationem). Both gangliectomy and cold condition led to an enhancement of serum TSH and pituitary TSH content. The exposure to cold was found to have a more severe influence. In the present study, we also have discussed the sympathetic denervation effect of the gangliectomy in relation to the thyroid and pineal gland. Due to certain contradictory data in the literature, we have also discussed the TRH-5-hydroxytryptamine (respectively melatonin) antagonism, though we were not able to determine whether peripheral and/or central mechanisms play the more important role in their regulation.

Animals↗

PubMed1986

[Model-free biomathematical analysis and description of correlations].

Modelfree methods for nonparametric estimation of unknown continuous functions from measured values and their advantages as against fitting of analytical expressions are discussed. The main features are stated especially of the empirical regression and of the local adjusted polynomial approximation. These topics and problems of application of the procedures are illustrated by 3 examples coming from chronobiological, neuromorphometrical, and histochemical examinations.

Adult↗

PubMed1986

[Effect of ganglionectomy (superior cervical ganglia) at normal temperature and exposure to cold on the circadian rhythm of liver glycogen and blood glucose levels of the Wistar rat with regard to the pineal gland].

Liver glycogen content and blood glucose level of 80 male Wistar rats were measured 4 times a day, 30 d after following surgeries: sham-operation without exposure to cold, sham-operation with exposure to cold (283 K, 72 h before killing), extirpation of the ganglia cervicalia superiora (GX) without exposure to cold, extirpation of the ganglia cervicalia superiora with exposure to cold (283 K, 72 h before killing). Exposure to cold alone as well as GX with and without exposure to cold modify the unimodal daily patterns (curves were calculated by means of empirical regression) of liver glycogen content and blood glucose level: there are changes from contrary localization of the maxima (and minima) of both, liver glycogen content and blood glucose level (exposure to cold alone) to nearly equal localization (GX alone). Compared to control group, all surgeries reduce the liver glycogen content statistical-significantly and also enhance the blood glucose level. Combination of GX with exposure to cold shows the strongest effect. In this case, the influence of GX is visible, but the effect is not significantly different from this of exposure to cold alone, which causes a high activation of the metabolism. To the contrary, a statistically significant influence is to be seen after GX alone, but the effect is lower than this one of exposure to cold. Extirpation of the ganglia cervicalia superiora and the resulting sympathetic denervation of the pineal gland is answered by comparable reactions of the investigated parameters as the extirpation of the pineal gland itself (90 d post operationem). Diminuation of liver glycogen content and enhancement of blood glucose level characterize the influence of gangliectomy (30 d post operationem) in this way, that the ratio of effect of factors causing hypo- and hyperglycemia is changed in favour of the latter.

Animals↗

PubMed1986

Improvement of the method of kernel estimation by local polynomial approximation of the empirical distribution function and its application to empirical regression.

The kernel estimation of an unknown density function derived from measured values has at least one disadvantage: the second central moment of the estimated density is greater than the sample variance. This is unsatisfactory. It is possible to reduce the difference between both variances by an improvement of the method of kernel estimation. But for improved GAUSS-kernels it is not possible to reduce it to zero.

Biometry↗

PubMed1986

[Acute normovolemic hemodilution in extensive surgical interventions].

In order to ascertain the effect of acute isovolaemic haemodilution on haemodynamics and various laboratory parameters as well as homologous blood consumption 44 patients undergoing major liver surgery were investigated in two groups: group I (n = 22) underwent acute normovolaemic haemodilution after induction of anaesthesia; group II (n = 22) had no blood withdrawn and served as control. Haemodilution led to typical haemodynamic effects such as increase in cardiac index and decrease in systemic as well as pulmonary vascular resistance; no detrimental effect of the procedure could be observed. Haemodilution led to a marked reduction in the consumption of banked blood which was on the average 1.8 units/patient against control intraoperatively and 3.1 units/patient postoperatively summing up to a total of 4.9 units/patient.

Adult↗

PubMed1986

[Case studies of the use of the locally adjusted polynomial regression].

Firstly the operation mode of the procedures of local adjusted polynomial regression is explained by an artificial example of data. After that, the properties of these nonparametric estimation procedures of unknown continuous functions from measured data are demonstrated by some examples arising in experimental examinations. Especially the aspect is discussed how far the main task of separating the deterministic component from the random one in the course of measured values may be fulfilled by using different degrees of polynomials in connection with different values of the smoothing parameter.

Biometry↗

PubMed1985

[Procedures of local approximation for nonparametric estimation of unknown continuous functions from given measurements].

There exists a lot of literature about the nonparametric estimation of unknown continuous functions from measured values. Many formulas of different shape were discussed. In this paper, we show that a great part of those formulas may be developed by using a uniformly mathematical principle which we name the local approximation by the least squares method. The knowledge of the principle enables one to develop new estimating formulas with special properties. The LOKONREG-, LOLINREG- and LOQUAREG-estimation are compared with each other by means of two biometric examples.

Animals↗

PubMed1984

[Quantitative and qualitative aspects of the representation of aging curves for the histological composition of the human submandibular gland by empirical regression].

A discussion of the possibilities is given of parametric and of nonparametric description of measured aging processes. As examples serve the counted volume portions of different histological structures in the human submandibular gland. As best suited approach the nonparametric evaluation of data by empirical regression is recommended. It is studied which qualitative changes are shown by the empirical regression curves if the sample size will be modified. For this the original sample size of 42 measured values is reduced in 2 steps to 35 and 29 values by removing at random firstly 7 and secondly additional 6 values. The tendencies in the aging courses represented by empirical regression curves will hardly altered by these reductions whereas a nonrandom elimination of outstanding points yields to marked changes in the calculated empirical regression curves. The influence of different local sample variances and densities of the measured points on the shape of the aging curves is stressed.

Adolescent↗

PubMed1984

[Methodological aspects of the preparation of measurements in animal experiment studies of metabolism].

Methodical aspects are discussed concerning an analysis of time series which result from experimental investigations of metabolic parameters in rats. Especially there are 2 questions. Should the measured temporal variations of the metabolic parameters be recorded model-free by empirical regression or by functional expression? Before treatment, a time-period was designed in which the rats could become a stable group. Should be chosen a steady description of the temporal parameter changes for the whole time-period of the experiment or should they be described separately for the periods of acclimating and of treatment? Especially due to the discrete time points of measurements, the 1st approach also allows the description of possible jumps in the parameter changing at the begin of the treatment. As consequence of the 2nd mode of description always a jump results. Further parametric and non-parametric statistical procedures are used for analysis of the time series and for comparisons of the time courses. In detail following statistical problems are discussed: Homogeneity of dispersion along a single-measurements course or along a mean value course, equality resp. parallelism of 2 courses, and local or global level differences between 2 courses. Finally it is pointed out that besides the characterization of the mean temporal variations of a parameter also the description of correlation between 2 parameters by empirical regression curve may give information on the mechanisms which give rise to the observed phenomena.

Animal Feed↗

PubMed1984

[Nonparametric estimation of 1-dimensional continuous distribution density functions using the continuous LOLINREG approximation].

A nonparametric method for estimation of one-dimensional continuous probability distribution functions is presented. Procedures for calculation of estimation of the unknown distribution function and the distribution density will be discussed in their application. 2 items are what type of weight function may be chosen for the proposed local-linear continuous approximation of the empirical distribution function by the least squares method (LOLINREG), and upon what value of bandwidth- or smoothing parameter one optimally should settle. The latter problem is practically very important with respect to the quality of the estimation results. Examples of simulated measurements which come from a standardized normal distribution as random numbers serve to demonstrate the mode of working, the advantages as well as the limits of the presented continuous LOLINREG-approximation.

Hip Dislocation, Congenital↗

PubMed1984

[A new procedure for estimating the distribution of measured values--demonstrated by morphometric examples].

The local approximation of the empirical distribution function of a one-dimensional continuous random variable leads to a continuous estimation of the distribution function. The first derivative of it gives the estimation of the density function. At a sample of growth data the advantages will be demonstrated of the continuous estimation compared with the classical approaches by histogram or frequency polygon respectively. Further advantageous aspects of the new approach will be illustrated by an example of a stomatologic-morphometrical examination and at one of caryometric research. Especially for comparison of 2 samples conclusions may be drawn by inspection and discussion of the obtained graphs of the empirical distribution functions and of the estimated density functions of the samples to be compared.

Body Height↗

PubMed1984

[On the concept of "information"].

The recent approaches of generalization of "information" beyond the classical field of communication theory are characterized by explication and by first suggestions of generalized information theories. A critical assessment of the two books "Information I" and "Information II" written by H. VOLZ are given to what extent they may contribute to this discussion. Especially, the new definition of an all-embracing notion of information given in these books is criticized because it seems not to be suited as basis for a generalized theory. In contrast to this, the idea of information as a measure of structural differences between probability distributions in a state space is proposed for mathematical description of specific biological properties in general. In this view, the one distribution is that of the physical possibilities and the other is that which is connected with the realizations by the biological system. The latter consists of the states which are optimal for the function of the biological system. They are selected from the set of physically possible states. As abstract mathematical quantity the statistical entropy of a random experiment is used. Finally it is indicated that this information-theoretical description may contribute to the understanding of the connections between physics, cybernetics, and biology.

Information Theory↗

PubMed1983

[Methodologic aspects of biomathematical description of growth processes].

The biomathematical processing of growth data aims the separation of the deterministic variation of the growth variable from the superposed random fluctuations. For the quantitative representation of the deterministic component, 3 possibilities are noted (mean values polygon, empirical regression, and least squares fitting of functions). By 2 examples of measured growth data, the suitability of these approaches will be discussed to give reproducible results and to avoid artifacts. The model free recording of the deterministic component by empirical regression is recommended.

Body Height↗

PubMed1983

[Locally adjusted linear regression and its possibilities for application].

A new numerical method is presented for a model free representation of the mean course in a series of measured data of an unknown functional connection. The usefulness of the method is demonstrated by some examples of different time series (chemical reaction kinetics, growth, damped oscillations of a physiological system, pharmacokinetics). The advantages of the new method compared with nonlinear regression or segmented linear regression are noted. For any argument within the interval of measurements, the local adjusted linear regression value may be calculated. In this way one get a continuous curve with a continuous 1st derivative, too. This local adjustment will be obtained by using a weight function which is from Gaussianlike type in our procedure. The calculated continuous approximation curve represents the mean course in the measured values and may serve for a further quantitative evaluation of the measured functional connection, for interpolative and smoothing purposes, or even for model construction and model proving procedures. The nonparametric estimation of a continuous (1 dimensional) distribution density function from realizations of a continuous random variable is another field of application of this method.

Animals↗

PubMed1983

[Comparative quantitative studies of mental and physical development of children up to age 3].

Biomathematical-methodical aspects are exposed of quantitative recording of mean growth courses which will be taken as basis for comparisons between different sample curves. In the paper the body length growth process of children in the age period from 0 to 3 years is considered. There are samples of children growing up under different social conditions and data of corresponding samples collected about 20 years ago. After remarks on the correlation between physical and psychical development of infants several possibilities for representing mean body length growth curves are discussed. The advantages of empirical regression are explained as the best suited method for a modelfree data evaluation. The nonparametric location trend test of Cox and Stuart is used for statistical proving of global difference or parallelism in the course of 2 mean growth curves. Level differences in the global sense between 2 compared curves may be tested by constructing a Scheffé confidence region for a properly defined constrast. Local level differences can be proved by the t-test for those pairs of corresponding mean values for which the conditions of applying this test are fulfilled. The calculation of a curve-related normal belt as a succession of 95%-tolerance regions (without confidence probability) is demonstrated by an example.

Age Factors↗

PubMed1983

[A method of non-parametric evaluation of one-dimensional continuous distribution density].

A continuous density function f(x) of a one-dimensional continuous random variable X is estimated from independent measured values xi, i = 1 (1) n, by a nonparametric procedure. If the measuring precision is sufficiently high, then the density estimation f(x) will be received from the 1st derivative of the LOLINREG-approximation of the empirical distribution function which is generated by the measured values. If the measured values are granulated by a lower measuring precision, then the density estimation f(x) may be obtained from the 1st derivative of the LOLINREG-approximation of an empirical distribution function which is calculated from the natural histogram by integration. The procedure is demonstrated by examples from biometrical research.

Animals↗

PubMed1982

[Morphometric studies of the aging of human submaxillary glands (author's transl)].

Morphometric examinations were made on hematoxylin-stained paraffin sections of 43 human submaxillary glands, in order to determine and describe histological changes of this organ during the aging thereof. The number of fat cells per unit area increases in the first decades, whereas that of the striated ducts decreases. Obviously, striated ducts differentiate earlier than serous acini, with the former thus being less subject to involution with aging than the latter. In old age, the nuclei of the epithelial cells of serous acini and striated ducts are characterized by the formation of certain classes of size, of which the association with polyploidization is, however, questionable. In a 44-year-old male, differences in the size of nuclei between different striated ducts of one section, which were due perhaps to functional peculiarities, indicated the existence of inactive and active glandular regions. The volume density of serous acini decreases continuously in the course of life, while that of the striated ducts decreases in the first decennia only. On the other hand, there was observed a continuous increase in the volume density of fat cells in the entire course of life and an increase of the volume density of connective tissue in the second half of life. The mucous fractions were observed to increase up through the fifth decade of life, after which they were seen to decrease continuously.

Adolescent↗