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Biomedical subjects

B Kinner

Publications and source records attributed to B Kinner.

At least 19 recordsLinked to original sources
PubMed2006

[Training in sports medicine for medical students--Evaluation of a practice-oriented teaching concept].

INTRODUCTION: Education in Sports Medicine is offered heterogeneously in German medical schools. Efficacy and acceptance among medical students are unknown. The self-image of sports has changed from a traditional, competition-oriented way to adventure, entertainment, wellness and health. Therefore changes of our curricula to a practical oriented way of teaching are required. In this regard a new curriculum was developed. The main focus, besides an interdisciplinary class in sports medicine was to offer practical education in sports to the students. METHODS: Efficacy and acceptance of the class were evaluated using a questionnaire. 90 medical students (58 male, 32 female) were included into the study . RESULTS: The interdisciplinary topics of the class were graded positively. Most of the presentations were regarded as very useful for the future practice. Empathy and commitment of the professor were keystones to good scores. The "fun-factor" was the key for the success of the practical assignment. Practical training was regarded as fundamental for a sports medicine class. DISCUSSION: Evaluation of the new concept as well as a discussion of the current practice to teach sports medicine at medical school confirm the need of a more practical oriented education, in order to meet the requirements of sports medicine in a time with changing self image of sports.

Curriculum↗
PubMed2005

Regeneration of articular cartilage.

Loss of articular cartilage from the ends of bones forming diarthrodial joints can be the source of profound pain and disability, and eventually lead to complete degeneration of the joint, necessitating total joint replacement. Until a few years ago, there seemed little hope of treating such defects. Novel surgical procedures and cell therapies have recently been found, however, to stimulate the formation of reparative tissue resulting in the relief of pain and restoration of function, at least for a limited time period. Moreover, studies of the healing of chondral defects in animal models have revealed that there is some potential for regeneration of this connective tissue. The introduction of certain biomaterial scaffolds along with selected surgical procedures and cell therapies has been demonstrated in animal studies to facilitate the cartilage reparative process and now offers the promise of extending the longevity of clinical treatments of cartilage defects. Collectively these findings provide the basis for the rational development of approaches for the more complete regeneration of articular cartilage, and demonstrate that meaningful clinical outcomes can be achieved even if complete regeneration is not achieved.

Animals↗
PubMed2004

[Treatment of dislocated 3- and 4-part fractures of the proximal humerus with an angle-stabilizing fixation plate].

In the presented prospective study 35 consecutive patients with displaced 3- and 4-part fractures of the proximal humerus, including fracture dislocations, were treated with a fixator plate comprising angular stability between May 2001 and December 2002. After 18.5 (8-29) months 31 (89%) fractures were available for follow-up. Good and very good results were obtained in 64%. A poor result was documented in 23%. 64% of the patients had no or mild pain, 71% were able to abduct the arm over 90 degrees . Fracture classification according to Neer and AO had no influence on the outcome, with a mean Constant Score of 76 points. Partial avascular necrosis (AVN) of the humeral head was seen in 16% of all cases representing 4% of the fractures without dislocation and 80% of the fracture dislocations. Fracture dislocation (p=0.02) and AVN (p=0.005) had a negative effect on the Constant Score, with AVN being a predictor for a high level of pain (p=0.04). Secondary dislocation of the greater tuberosity was seen in two patients, loosening of screws in one patient and a fracture below the plate in another one. Secondary dislocation or loss of reduction of the head was not recorded. Angle stable plate fixation with tension band wiring of the tuberosities is an effective and safe option to treat this difficult fractures, also in elderly patients with osteoporotic bone. Because 40% of the 4-part fractures with fracture dislocation yielded a satisfactory or better result, the plate fixator with angular stability may be an alternative to prosthetic replacement in selected cases.

Adult↗
PubMed2003

Expression of smooth muscle actin in cells involved in distraction osteogenesis in a rat model.

Distraction osteogenesis has proven to be of great value for the treatment of a variety of musculoskeletal problems. Little is still known, however, about the phenotypic changes in the cells participating in the bone formation process, induced by the procedure. Recent findings of the expression of a contractile muscle actin isoform, alpha-smooth muscle actin (SMA), in musculoskeletal connective tissue cells prompted this immunohistochemical study of the expression of SMA in cells participating in distraction osteogenesis in a rat model. The tissues within and adjacent to the distraction site could be distinguished histologically on the basis of cell morphology, density, and extracellular matrix make-up. The percentage of SMA-containing cells within each tissue zone was graded from 0 to 4. The majority of the cells in each of the zones stained positive for SMA within five days of the distraction period. The SMA-containing cells included those with elongated morphology in the center of the distraction site and the active osteoblasts on the surfaces of the newly forming bone. These finding warrant further investigation of the role of this contractile actin isoform in distraction osteogenesis and investigation of the effects of modulation of this actin isoform on the procedure.

Actins↗
PubMed2002

Regulation of smooth muscle actin expression and contraction in adult human mesenchymal stem cells.

Prior studies have demonstrated the expression of a contractile actin isoform, alpha-smooth muscle actin, in bone marrow stromal cells. One objective of the current study was to correlate contractility with alpha-smooth muscle actin expression in human bone marrow stroma-derived mesenchymal stem cells. A second objective was to determine the effects of transforming growth factor-beta1, platelet derived growth factor-BB, and a microfilament-modifying agent on alpha-smooth muscle actin expression and alpha-smooth muscle actin-enabled contraction. Adult human bone marrow stromal cells were passaged in monolayer and their inducibility to chondrocytic, osteoblastic, and adipogenic phenotypes was demonstrated. Western blot analysis was employed along with densitometry to quantify the alpha-smooth muscle actin content of the cells and their contractility was evaluated by their contraction of a type I collagen-glycosaminoglycan sponge-like matrix into which they were seeded. Transforming growth factor-beta1 (1 ng/ml) significantly increased and platelet-derived growth factor-BB (10 ng/ml) decreased alpha-smooth muscle actin expression and the contractility of the cells. Cytochalasin D also blocked cell contraction. There was a notably high correlation of cell-mediated contraction normalized to the DNA content of the matrices with alpha-smooth muscle actin content of the cells by linear regression analysis (R(2) = 0.88). These findings lay the groundwork for considering the role of alpha-smooth muscle actin-enabled contraction in mesenchymal stem cells and in their connective tissue cell progeny.

Actins↗
PubMed2002

Expression of smooth muscle actin in osteoblasts in human bone.

It is well known that certain connective tissue cells (viz., dermal fibroblasts) can express the gene for a muscle actin--alpha-smooth muscle actin--and can contract. This process contributes to skin wound closure and is responsible for Dupuytren's contracture. The objective of this study was to determine if human osteoblasts can also express the gene for alpha-smooth muscle actin. Immunohistochemistry using a monoclonal antibody for alpha-smooth muscle actin was performed on human cancellous bone samples obtained from 20 individuals at the time of total joint arthroplasty. The percentages of resting and active osteoblasts on the bone surfaces containing this muscle actin isoform were evaluated. Explants of human bone were also studied for the expression of alpha-smooth muscle actin in the tissue and in the outgrowing cells with time in culture. Western blot analysis was performed to quantify the alpha-smooth muscle actin content of the outgrowing cells relative to smooth muscle cell controls. Nine +/- 2% (mean +/- SEM; n = 20) of the cells classified as inactive osteoblasts and 69 +/- 3% (n = 19) of the cells identified as active osteoblasts on the bone surface contained alpha-smooth muscle actin. This difference was highly statistically significant (Student's t test, p < 0.0001). Similar profiles of alpha-smooth muscle actin-expressing cells were found in explants cultured for up to 12 weeks. Cells forming a layer on the surface of the explants and growing out from them in monolayer also contained alpha-smooth muscle actin by immunohistochemistry and Western blot analysis. Human osteoblasts can express the gene for alpha-smooth muscle actin. This expression should be considered a phenotypic characteristic of this cell type, conferred by its progenitor cells: bone marrow stromal-derived stem cells, and perhaps pericytes and smooth muscle cells.

Actins↗
PubMed2002

Expression of smooth muscle actin in connective tissue cells participating in fracture healing in a murine model.

The role of alpha-smooth muscle actin (SMA)-expressing fibroblasts in the contraction of skin wounds has been known for three decades. Recent studies have demonstrated that osteoblasts can also express the gene for this contractile muscle actin isoform and can contract a collagen-glycosaminoglycan analog of extracellular matrix in vitro. These findings provided rationale for the hypothesis that SMA-expressing cells contribute to fracture healing by drawing the bone ends together. To begin to test this hypothesis, immunohistochemistry was employed to evaluate the distribution of connective tissue cells expressing SMA in a mouse model of successful fracture healing. The results demonstrated that the majority of the cells comprising the mesenchymal tissue interposed between the fracture ends contained SMA after 7 and 21 days, supporting the working hypothesis. Most of the osteoblasts lining the surfaces of newly forming bone and the chondrocytes comprising the cartilaginous callus also expressed this contractile actin isoform. The maximal SMA expression extended from 7 to 21 days postfracture. The finding of high levels of SMA expression in connective tissue cells participating in fracture healing suggests that SMA-enabled contraction may be playing a role in the healing process. These results warrant further study of the specific SMA-dependent cell behavior.

Actins↗
PubMed2001

Growth factor regulation of smooth muscle actin expression and contraction of human articular chondrocytes and meniscal cells in a collagen-GAG matrix.

Recent work has demonstrated that human articular chondrocytes and meniscus cells can express the gene for a contractile actin isoform, alpha-smooth muscle actin (SMA), in vivo. The objective of the present study was to evaluate the effects of two growth factors, transforming growth factor (TGF)-beta1 and platelet-derived growth factor (PDGF)-BB, on the SMA content of these cells and their contraction of a collagen-glycosaminoglycan (GAG) analog of extracellular matrix in vitro. TGF-beta1 was found to markedly increase SMA content of the cells and PDGF-BB decreased SMA expression, with both findings achieving statistical significance. A notable finding was the increased contraction of the collagen-GAG matrix induced by TGF-beta1 and the decrease in contraction resulting from PDGF-BB treatment, indicating a causal relationship between expression of SMA and the contractility of the cells. A novel cell force monitor, employed to estimate the force exerted per cell, demonstrated a higher force exerted by the TGF-beta1-treated cells. The findings demonstrate that the expression of SMA by articular chondrocytes and meniscal cells and their associated contractile behavior can be regulated by selected growth factors. This work provides a foundation for the rational investigation of the mechanisms underlying SMA-enabled contraction of these cell types and the control of this behavior in tissue engineering.

Actins↗
PubMed2001

Smooth muscle actin expression by human articular chondrocytes and their contraction of a collagen-glycosaminoglycan matrix in vitro.

Recent studies have demonstrated that human articular chondrocytes can express the gene for a contractile muscle actin, alpha-smooth muscle actin (SMA), in situ. One objective of this work was to evaluate the SMA-content of isolated human articular chondrocytes using Western blot analysis and to correlate the amount of SMA in the cells with passage number and the number of days in culture. A second objective was to determine if articular cartilage-derived cells expressing the gene for SMA in vitro also continue to express type II collagen. A final aim of the current study was to determine if SMA-containing cartilage-derived cells were capable of contracting a collagen glycosaminoglycan analog of extracellular matrix in vitro. Articular chondrocytes were isolated from 13 patients undergoing total joint arthroplasty. Cells were serially passaged through passage 7. Samples were allocated for Western blot analysis of SMA. Cells in monolayer culture were also stained immunohistochemically for SMA and type II collagen. Cells from passage 3 and 7 were seeded into a porous type I collagen-glycosaminoglycan matrix and the diameter of the scaffolds measured every other day for 21 days. Immunohistochemistry of the articular cartilage samples revealed SMA in the articular chondrocytes in situ with a greater percentage of cells staining positive in the superficial half (60 +/- 1.2%; mean +/- SEM) of the cartilage than in the basal half (28 +/- 1.3%). There was an increasing amount of SMA in the cells in monolayer culture with passage number and a meaningful correlation of the SMA content with the days in culture (linear regression analysis; R2 = 0.72). Double staining for SMA and type II collagen showed that type II collagen-expressing cells in monolayer could also express SMA. SMA-containing cells were found to contract the collagen glycosaminoglycan matrix, with the cells containing more SMA (passage 7 cells) displaying more matrix contraction than those with a lesser amount of SMA (passage 3 cells). The results indicate that control of the expression of SMA may be important when employing articular chondrocytes, expanded in monolayer culture, for implantation alone or in a cell-seeded matrix for cartilage repair procedures.

Actins↗
PubMed1998

[Effect of adenosine on intravascular accumulation of leukocytes and tissue damage in striated muscle in endotoxemia].

Under the experimental conditions of endotoxinemia, the therapeutic use of an intravenous infusion of adenosine (110 micrograms x kg-1 x min-1) has been investigated in the microcirculation model of the BALB/c mouse. Injection of S. abortus-equi endotoxin (2 mg x kg-1 body wt. i.v.) elicited a significant increase of sticking leukocytes in postcapillary venules of striated skin muscle, which was associated with a swelling of microvascular endothelium and striated skin muscle. Infusion of adenosine effectively attenuated the endotoxin induced enhancement of leukocyte sticking and preserved microvascular endothelial and striated muscle integrity. These results imply the use of adenosine as therapeutic concept during endotoxinemia.

Adenosine↗
PubMed1989

[The relation of anthropometric parameters and echocardiography findings in the evaluation of left ventricular form and function in extreme obesity].

For the characterization of the left-ventricular thickness of the wall, of the diameter and of the functional parameters in obesity in a short-term investigation on 18 extremely adipose female normotonics and 17 normotonics with normal weight the echocardiographic investigation in the M-mode in the short parasternal axis was performed. The women with overweight had a by 28% (p less than 0.001) greater fractional shortening, a by 8% (p less than 0.01) greater ejection fraction, a by 23% (p less than 0.05) greater stroke volume and a by 34% (p less than 0.001) greater cardiac output as well as a by 13% smaller left-ventricular end-systolic volume than normotonic women with normal weight. Index of stroke volume and cardiac output did not differ. The women with overweight had a significantly larger left-ventricular end-diastolic diameter and a thicker interventricular septum as well as a larger thickness of the left-ventricular posterior wall in the systole. The results allowed the conclusion that changed left-ventricular parameters both with regard to the form and to the function in obesity per se might be the expression of the physiological adaptation to an increased requirement and the borderlines to the transition into a disturbed left-ventricular function and development of a left-ventricular hypertrophy were not fixed. Long-term studies should bring further explanation concerning these problems.

Adult↗
PubMed1986

[Nutrition and aging].

Proceeding from experiences with animal-experimental studies is tried to show all those mechanisms which have influence on the ageing process of man. In these cases in the experimental part of the study is particularly investigated the influence of the restriction of food in obese patients on the cardiovascular system, the lipid metabolism and the biological age. In obese patients of middle age by isocaloric reduction diet a normalisation of the at present changed non-invasive cardiodynamic parameters could be achieved. Apart from a normalisation of cholesterol and LDL-cholesterol, however, a decrease of the HDL-cholesterol of the same intensity was found. The biological age could be influenced under restriction of food. To what extent overweight and food restriction in man closely correlate with the life expectancy remains the subject of further investigations.

Adult↗
PubMed1985

[Changes in noninvasive cardiovascular parameters by inpatient weight reduction].

36 normotensive obese and 23 hypertensive obese were treated with an isokaloric reduction diet of 800 kcal/a day under clinical conditions over a 4-week span. Blood pressure and cardiac performance were investigated by means of non-invasive techniques such as systolic time intervals (STI) and calculated indices. A significant decrease was established in systolic time intervals such as left ventricular ejection time and total electromechanical systole, systolic and diastolic blood pressure, myocardial oxygen consumption and cardiac output. Heart rate, preejection index and stroke volume were not diminished under dietary treatment. No decrease of all parameters was found in obese normotensives with a weight reduction greater than 5% after dietary treatment.

Adult↗
PubMed1983

[Effect of obesity on cardiovascular performance].

On 55 healthy test persons with normal weight and 76 healthy middle-aged obese test persons the measurement of systolic time intervals was performed standing and lying. In 39 obese patients and 55 test persons with normal weight a load ergometry was carried out. No significant difference between persons with normal weight and extreme overweight was recognized with regard to the index of tension. However, there were clear differences between persons with normal and overweight as to the time of tension and left-ventricular ejection time lying and standing, independent of the behaviour of blood pressure. In persons with overweight a significantly lower cardiac output was found. The index of tension of obese persons with a degree of efficacy below 75 Watt was on an average 1.04. Only half of the persons with overweight reached a degree of efficacy of 100 Watt. In 32 obese persons with a degree of efficacy of more than 75 Watt the regulation of frequency and blood pressure did not differ from that of persons with normal weight.

Adult↗
PubMed1981

[Metabolic risk factors in the very old].

55 patients well advanced in years of the vitality group I after Franke were examined according to clinical and laboratory-chemical criteria as well as by means of ECG in rest. The particular relations between metabolic risk factors and the occurrence of diseases of heart and circulation in persons well advanced in years were explained. Here could be established that persons who advanced in years, on the one hand, from the epidemiologic point of view show favourable laboratory parameters for the metabolic risk factors, on the other hand, however, slightly increased serum values of the risk factors may also be connected with old age. In a similar way the finding from the ECG in rest could be interpreted.

Aged↗
PubMed1981

[Preconditions for attaining advanced old age (author's transl)].

Generally speaking, we can say that the incidence of certain diseases in the various blood groups of the ABO system do not demonstrate a direct connection which might be used for the assessment of life expectancy, but that exogenic and genetic factors form a genetically determined functional unity in the development of certain characteristic features and of diseases. Innumerable influences of various types can cause diseases, primarily the high incidence of certain tumours in old age, climatic influences, overeating and malnutrition, furthermore abuse of coffee, tea, tobacco and alcohol, medicines and insufficient movement. It can be assumed that wherever blood group A is prevailing the genes of blood group A constitute a factor in the respective polygenic system. The impact of the blood group genes varies as a function of the underlying disease, the effectiveness of the exogenic factors and the general constitution of the individual patient.

ABO Blood-Group System↗
PubMed1981

[Electrocardiographic studies and cardiovascular radiographic findings in the aged].

Humans far advanced in years represent, in many respects, a positive selection of people showing particularly favorable adaptation to life circumstances. Correlated with the behavior of blood pressure were not only electrocardiographic results but cardiovascular x-ray results as well. Pathological ECG changes which are not affected by a specific therapy are entirely consistent with old age, with pronounced ECG changes accompanied by a marked variation in hemodynamics having not been observed in the aged in the sense of a positive selection. The aged, despite a large number of subjects showing development of particular conditions, did not generally include R1 patients with strain on both the left and right heart. On an average, the width of the aorta was not seen to increase further in the aged. Also, hypertension had no effect upon the width of the aorta in humans of advanced age. There was no evidence for an increase in the incidence of aortic sclerosis in the aged.

Adult↗