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Biomedical subjects

H Helwin

Publications and source records attributed to H Helwin.

18 recordsLinked to original sources
PubMed1992

[Hyperextension somersault trauma].

Neurological failure can occur as one feature of hyperextension trauma of the cervical spine. Apart from predisposing factors, such as dorsal osteophytes and congenital spinal stenosis, an acute narrowing of the spinal canal caused by a hyperextension somersault trauma can cause such a trauma. We observed three cases of paraplegic syndrome resulting from hyperextension somersault trauma of the cervical spine. Fast recovery from the symptoms within 12 h indicates vascular damage. The mechanism of the accident is shown with reference to clinical and experimental investigations. Hyperextension somersault trauma is characterized by a plunge from a low height, with the danger of somersaulting of the body and impact at the forehead while the head is retroflected. For this reason, extension treatment ought to be contraindicated if an accident of this kind has happened. Emphasis should be placed on adequate positioning of the patient.

Adolescent↗
PubMed1989

[Periodic local approximation for the model free description of measurement courses of biorhythmic processes--demonstration example for the selection of smoothness parameters].

Measured time series with known basic periodicity may be modelfreely evaluated by procedures of local adjusted approximation. Examples of motility time series recorded in chronobiological experiments in the seasonal course of a year demonstrate aspects of choosing values of the smoothing parameter and the resulting effects for the quantitative description of the measured variations as well as for their interpretation.

Animals↗
PubMed1988

Creatine kinase in hypo- and hyperthyroid rats under consideration of the circadian oscillations.

Thyroxine level (T4) and total creatine kinase-activity (CK) were measured in serum samples from male Wistar-rats to investigate the relationships of serum titers after exposure to cold and thyroidectomy (TX). 72 hours exposure to cold (10 degrees C) produced a statistically significant elevation of T4 and a diminuation of CK-activity. In contrast to this protocol, TX (90 days after operations) reduced the T4 level and enhanced the CK-activity. These reactions were likewise statistically significant. The presented results are in agreement with the previous proposal which consists in inverse correlation between the T4 level and the CK-activity at hypo- and hyperthyroid states. Additionally it was shown that the highest activity of the serum CK appears in the first half of the light phase of the day under normal ambient temperature (24 degrees C) as well as under exposure to cold (10 degrees C).

Animals↗
PubMed1979

[Quantification of environmentally influenced differences in physical and mental development of infants by a phenomenologic-mathematical separation of the body length growth into growth spurts (author's transl)].

Retardation phenomena in the physical development--especially in the increase of body length--of infants taken care of in social institutions (day-nursery, week-nursery, residential nursery) in relation to those growing up in the family will be represented in a quantitative-analytical form on the basis of a phenomenologic-mathematical model. This kind of modelling consists in the separation into 7 successive growth periods (growth spurts) of the whole growth process during the time interval from conception until the age of 3 years. For the time interval from birth until the end of 3 years we have 4 such growth spurts. The second one (fifth in the former numbering) determines mainly the growth during the 2nd year of the individual's life and makes evident the delay in the mean increase of body length of infants taken care of in social institutions, which is most evident for children who grow up in a residential nursery. The quantitative statements derived from the mathematical model concerning the physical development will be confronted with the known facts concerning the retardation in the mental-psychial development--especially in the ontogenesis of speech--of the same groups of children. There is an astonishingly close accordance of the values of time delays in reaching the levels of the physical and of the psychical development. The model may help to perceive and to diagnose the complex of causes responsible for these retardation phenomena from a social-medical and biological point of view. On the other hand this may also give a critizism and assessment of the real relevance of the biomathematical separation of the growth process into single growth spurts practiced here.

Body Height↗
PubMed1979

[Quantitative mathematical evaluation of growth studies from the viewpoint of exogenously or genetically influenced variability].

Firstly, the ideas are sketched which serve as the basis for the phenomenologic-mathematical kind of modeling of the body length growth process of man. For proving the biological relevance of the spurts analyzed by numerical procedures one has to consider the social and the biological circumstances in which the growth process takes place. An analysis of longitudinal data series of the body length of (monozygotic) twins will give further hints to the possible meaning of the growth spurts by way of separation of exogenous and of genetic determined endogenous agents on the growth process. The data available for our examinations cover the time interval of the praepubertal and the postpuberal development as well as the time interval in which the puberal growth spurt takes place. The way to proceed in evaluation these time series will be presented.

Adolescent↗
PubMed1977

[Phenomenologic-mathematical modeling of the human-body-length growth through the analysis of growth periods and their quantitative-analytical registration].

The body height growth (of masculine beings) was modelled in a phenomenologic-mathematical manner by partitioning the time course of measured growth curve in parts every of which corresponds to a separated growth period. This partitioning was reached in a natural way so that a superposition of the single spurts yields the whole measured course. Every growth batch will be described in its time course by one term of inverse tangent function. The biological meaning and an explanation of the succession of the growth spurt as an effect of control circuits need further exploratory work. For detailed statements on acceleration phenomena concerning the body height growth this analysis gives possibilities for comparing the single growth spurts of the mean growth process of two populations in question. For measured values given by BROCK (1954) and SALZLER (1967) there are five growth periods in the time intervall reaching from time of conception until the end of the first year. Comparing the mathematical functions of the corresponding growth spurts for these two groups one can conclude that the second spurt (fetal spurt) is responsible for an increase of birth body height and the fourth for an increase of body height in the suckling age of the latter group against the former one.

Adolescent↗
PubMed1977

[Quantitative analytical registration of body-length growth in man].

Measured values concerning the body hight growth process of male human beings, and reaching from praenatal to adult state are taken from anthropometric literature. After a discussion of the mathematical tools for description (differential equation, analytical function), and of the problems connected with subdividing the whole growth period in subsequent periods the results of numerical adjustments of growth functions to measured courses of these subperiods are presented. The obtained goodness of fit is excellent so that for the purpose of formal quantitative description of the whole growth process a set of mathematical functions is available. Each of these expressions is effective only in the time interval of the corresponding growth subperiod. This set of mathematical functions will provide a objective basis for further investigations, especially for comparisons between populations, and for a mathematical analysis of acceleration phenomena in development. In the last part of the paper a mathematical-phenomenological model for the growth process is sketched. The main features of this model consist in a subdividing of the whole process in growth parts with a biological meaning, and in a mathematical description of these parts which are mutually independent but superposing one with another. Therefore the number of growth parts and also of mathematical terms are determined by biological (theoretical or phenomenological) arguments. Now each of these calculated function terms is valid for the whole time intervals in which the body hight growth process performs. The entirety of all these terms gives a seamless steady description of the changes of the growth variable in time.

Adolescent↗
PubMed1976

[Quantitative description of growth processes in man as a basis for the objective comparison of sex-specific data for various body measurements].

To compare growth processes of feminine human beings with such one of masculine we have taken as realizations of the growth characteristic the morphological height of face (distance between nasion and gnathion), length of nose (distance between nasion and subnasale) and body length of two spatially and temporally different populations. Measured values of these characteristics for different ages of individuals provide the basis for mathematical evaluation. The parameters of the following three types of mathematical functions were adjusted to the measured time course of the growth characteristics: Gompertz' function, inverse tangent and the generalized logistic growth function. The principal possibilities are explained which a mathematical expression can offer for qualitative and quantitative description of dynamical processes. The results of fitting the 3 competitive function types to the course of the measured values are given and several quantitative conclusions are demonstrated arising from comparisons of corresponding growth processes of feminine and masculine human beings.

Anthropometry↗