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Biomedical subjects

O Fricke

Publications and source records attributed to O Fricke.

9 recordsLinked to original sources
PubMed2006

The principle of regulation in biology--from bone to eating behavior.

Cell physiology and molecular biology typically follow a reductionistic approach in science. In the last decade, molecular principles and pathogenetic factors involved in the development of many diseases have been successfully discovered. Therefore, early biological concepts based on systemic and cybernetic thoughts have been largely overshadowed by these more recent molecular and pathogenetic factors. This review highlights discoveries on bone development and hypothalamic controlled feeding and eating behavior with a cybernetic and systemic perspective. Interestingly, ancient ideas on bone development and hypothalamic function are still reasonable considerations to embed new molecular discoveries into a systemic concept of principles organizing nature.

Animals↗
PubMed2005

A cybernetic approach to osteoporosis in anorexia nervosa.

A group of 25 female individuals, who had been admitted to the University Hospital with the diagnosis of anorexia nervosa (AN) 3 to 10 years before, was seen for a follow-up visit in the hospital. These women got a psychiatric exploration to detect a present eating disorder. Moreover, parameters of the muskuloskeletal interaction were determined on the non-dominant forearm. Bone mineral content (BMC) of the radius was measured by pQCT and maximal grip force was evaluated by the use of a dynamometer. Eating disorders were present in 12 females. The mean of BMC standard deviation (SD) score was significantly reduced in comparison with reference values. Furthermore, the mean of BMC SD score was also significantly lower than the mean of grip force in SD score. These results gave the suggestion that the adaptation of bone mass to biomechanical forces is disturbed in AN. The linear regression analyses between the parameters grip force and BMC were compared between the study and the reference group. The comparison delivered a significantly lower constant in the regression equation of the study group. This result can be interpreted on the background of the mechanostat theory. The affection with an eating disorder decreases the set point in the feedback loop of bone modeling. The results offer for the first time the possibility to analyse osteoporosis in anorexic females under the paradigm of muskuloskeletal interaction.

Adolescent↗
PubMed2003

The regulation of bone development as a biological system.

A large number of molecular, cellular, and epidemiologic factors have been implicated in the regulation of bone development. A major unsolved problem is how to integrate these disparate findings into a concept that explains the development of bone as an organ. Often, events at the organ level are simply presented as the cumulative effect of all factors that individually are known to influence bone development. In such a cumulative model it must be assumed that each bone cell carries the construction plan of the entire skeletal anatomy in its genes. This scenario is implausible, because it would require an astronomical amount of positional information. We therefore propose a functional model of bone development, which is based on Frost's mechanostat theory. In this model, the genome only provides positional information for the basic outline of the skeleton as a cartilaginous template. Thereafter, bone cell action is coordinated by the mechanical requirements of the bone.

Animals↗
PubMed2001

Analysis of cancellous bone turnover by multiple slice analysis at distal radius: a study using peripheral quantitative computed tomography.

We compared the results of peripheral quantitative computed tomography (pQCT) measurements (XCT-900; Stratec) at the 4% site of the distal radius (section 1; slice thickness of 2 mm) and in two proximally adjacent sections (sections 2 and 3). The study population consisted of 138 ambulatory patients (age 16.4 +/- 5.6 yr; mean +/- SD; 71 female) who were referred to a pediatric densitometry unit. Total volumetric bone mineral density (BMD) increased, whereas the area of the radial cross-section decreased in a proximal direction. There was a decrease in bone mineral content between sections 1 and 3, which was more pronounced in subjects under age 16. Cancellous BMD significantly decreased from section 1 to 3 only under the age of 16. In 12 patients under age 17 who suffered from increased bone fragility, cancellous BMD decreased about 2.5 times more between sections 1 and 3 than in age-matched patients who received anticonvulsant therapy but had a normal neurologic and musculoskeletal status (-21.4% +/- 16.9 vs -8.1% +/- 6.3; p = 0.02). This suggests that in the bone fragility group, trabeculae were removed faster during longitudinal growth of the radius. In conclusion, multiple slice analysis may provide information on the dynamic turnover of metaphyseal trabeculae during growth.

Adolescent↗
PubMed2000

Chemiluminescence immunometric assay for measuring osteocalcin in healthy children.

Osteocalcin (OC) was measured in serum samples from 92 children and adolescents (57 females, 35 males) by a two-site chemiluminescence immunometric assay (Nichols Institute Diagnostics, USA), which recognizes the 1-19 region of the whole molecule as well as the large N-terminal midregion fragment representing the main part of OC in serum. The highest OC levels are measured between the age of 10-15 years. The linear correlations between OC and alkaline phosphatase were 0.65 (p < .01) for total alkaline phosphatase (TAP) and 0.61 (p < 0.1) for bone alkaline phosphatase (BAP).

Adolescent↗
PubMedDate not supplied

Examining the developing skeletal muscle: Why, what and how?

This review focuses on methodological concepts in the evaluation of skeletal muscle function, taking into account classical muscle physiology, the developing motor system in children and anthropometric parameters. Thereby, the classical concept of kinetic and thermodynamic description of muscle function is discussed in relation to data pertaining to human physiology. Emphasis is given to the specific problems that arise when assessing muscle function during development. Two important factors influencing muscle function are discussed in detail: changes in anthropometric characteristics and changes in co-ordinative skills in the developing individual. Finally, we discuss currently available methods for the evaluation of anaerobic muscle function in children and adolescents (maximal isometric grip force, peak jump force, peak jump power, Wingate test, Bosco test).

Adolescent↗