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T Steffen

Publications and source records attributed to T Steffen.

46 records · Page 3Linked to original sources
PubMed1997

A new technique for measuring lumbar segmental motion in vivo. Method, accuracy, and preliminary results.

STUDY DESIGN: A direct method for three-dimensional in vivo spine kinematic studies was developed and used to measure segmental motion patterns in healthy subjects. OBJECTIVES: To validate the new method, and to study the L3-L4 segmental motion patterns for complex dynamic movements. SUMMARY OF BACKGROUND DATA: Conventional two-dimensional and three-dimensional radiographic methods have been used in the past to study spine kinematics. Few studies provided a direct approach to study segmental kinematics. No dynamic recordings of three-dimensional segmental motion patterns have been reported previously. METHODS: In 16 healthy men, Kirschner wires were inserted in the spinous processes of L3 and L4. Electromagnetic tracking sensors were attached to the pins. Motion data recorded during ranging exercises were used with biplanar radiographs to calculate L3-L4 segmental motion patterns. Errors resulting from pin deformation and the dynamic accuracy of the tracking system were investigated thoroughly. RESULTS: The average range of motion for flexion-extension was 16.9 degrees, for one side lateral bending 6.3 degrees and for one side axial rotation 1.1 degrees. Large intersubject variation was found in flexion-extension with values ranging from 7.1 to 29.9 degrees. Coupled motion patterns were found to be consistent among subjects in active lateral bending and inconsistent for active axial rotation. CONCLUSIONS: This new method offers dynamic recording capabilities and a measurement error comparable with stereo radiographic methods. Repetitive ranging experiments are highly reproducible. The range of motion for axial rotation seems overestimated in previous cadaveric studies. Coupling patterns show large variations between individuals.

Electromagnetic Phenomena↗
PubMed1996

The human lumbar intervertebral disc: evidence for changes in the biosynthesis and denaturation of the extracellular matrix with growth, maturation, ageing, and degeneration.

Very little is known about the turnover of extracellular matrix in the human intervertebral disc. We measured concentrations of specific molecules reflecting matrix synthesis and degradation in predetermined regions of 121 human lumbar intervertebral discs and correlated them with ageing and Thompson grade of degeneration. Synthesis in intervertebral discs, measured by immunoassay of the content of a putative aggrecan biosynthesis marker (846) and the content of types I and II procollagen markers, is highest in the neonatal and 2-5-yr age groups. The contents of these epitopes/molecules progressively diminished with increasing age. However, in the oldest age group (60-80 yr) and in highly degenerated discs, the type I procollagen epitope level increased significantly. The percentage of denatured type II collagen, assessed by the presence of an epitope that is exposed with cleavage of type II collagen, increased twofold from the neonatal discs to the young 2-5-yr age group. Thereafter, the percentage progressively decreased with increasing age; however, it increased significantly in the oldest group and in highly degenerate discs. We identified three matrix turnover phases. Phase I (growth) is characterized by active synthesis of matrix molecules and active denaturation of type II collagen. Phase II (maturation and ageing) is distinguished by a progressive drop in synthetic activity and a progressive reduction in denaturation of type 11 collagen. Phase III (degeneration and fibrotic) is illustrated by evidence for a lack of increased synthesis of aggrecan and type II procollagen, but also by an increase in collagen type II denaturation and type I procollagen synthesis, both dependent on age and grade of tissue degeneration.

Adult↗
PubMed1996

The human lumbar endplate. Evidence of changes in biosynthesis and denaturation of the extracellular matrix with growth, maturation, aging, and degeneration.

STUDY DESIGN: The authors measured concentrations of specific molecules reflecting matrix synthesis and degradation in 121 human endplates and correlated them with aging and grade of degeneration. OBJECTIVES: Abnormal endplate development has been implicated in many spinal abnormalities, yet little is known about endplate matrix component turnover. SUMMARY OF BACKGROUND DATA: Techniques are available to perform an in situ investigation of matrix component turnover with aging and degeneration. METHODS: Newly synthesized aggrecan and Type I and Type II procollagens were measured with recently developed immunoassays. Percentage of denatured Type II collagen was assessed with a new enzyme-linked immunosorbent inhibition assay. RESULTS: Synthesis in endplates, measured by content of an aggrecan marker (846) and content of Types I and II procollagen markers (CPI and CPII), is highest in the neonatal and 2- to 5-year age groups and steadily diminishes with increasing age. However, in the oldest age group and in highly degenerated discs, the CPI epitope level increased significantly. Percentage of denatured Type II collagen, assessed by the presence of an epitope exposed with the cleavage of Type II collagen, increased from the neonatal to the 2- to 5-year age groups. The percentage progressively decreased with increasing age. However, it significantly increased in endplates from highly degenerated discs. CONCLUSIONS: The authors identified three matrix turnover phases, related to age and grade of degeneration. Phase I (growth) is characterized by active synthesis of matrix molecules and active denaturation of Type II collagen. Phase II (aging and maturation) is distinguished by a drop in synthetic activity and a reduction in denaturation of Type II collagen. Phase III (degenerative) is illustrated by an increase in Type II collagen denaturation and Type I procollagen synthesis, both related to grade of tissue degeneration.

Adolescent↗
PubMed1996

Cholesterol screening in childhood: results of a 9-year follow-up study in Swiss and Italian children in Switzerland.

Mass screening for blood cholesterol as part of routine preventive health care of children continues to be discussed in several countries. Results of longitudinal studies underline the importance of the predictive value of cholesterol levels assessed during childhood. Some countries have changed their recommendations during the past years to blood cholesterol screening for obese children only or for children of high risk families. In the Kindergarten-study Basel, a follow-up study on somatic, psychic and social development of Swiss and immigrant schoolchildren, cardiovascular risk factors were assessed at the ages of 5, 10 and 14 years. The age-specific levels of total and LDL-cholesterol found in our study were slightly higher and HDL-cholesterol lower than, for example, those found in the Bogalusa Heart Study. For total cholesterol no significant tracking correlations over the 5 and 9 year periods were found. Tracking of LDL- and HDL-cholesterol differed between nationalities and sexes. The total cholesterol/HDL-cholesterol index tracked slightly better. Italian girls showed the best 9-year tracking for HDL-cholesterol (r = 0.56). The differences between this and other studies can only partially be explained by different sampling and laboratory methods. Individual changes in cholesterol levels between the ages of 5 and 14 were marked. Sexual maturation was found to be of minor influence. Body mass index was the most consistent risk factor in our population. Changes of sex or growth hormone levels during puberty, but also changes of nutritional habits or physical activity might influence the individual cholesterol levels. Before recommendations on mass screening of cholesterol in children are made, the different longitudinal patterns of changes in cholesterol levels, and subpopulation-specific changes of nutritional habits and physical activity, should be discussed. The results of the Kindergarten study Basel suggest that attention should be paid to screening for obesity and to health education regarding nutrition and physical activity.

Adolescent↗
PubMed1994

Twelve years follow-up of fractures of the distal radius treated with the AO external fixator.

From 1977 to 1982 a total of 55 patients suffering comminuted fracture of the distal radius were treated with the external fixator. Fifty of these were followed up in 1983/85 and 32 of them were available for assessment in this study (1992). The follow-up period was 11.6 years on average. All patients had suffered an intra-articular fracture (91% a C-fracture, 9% a B-fracture according to the AO classification), 27 patients had also fractured the ulnar styloid process and in 11 a dye-punch fragment was present. Both wrists were assessed on the basis of case history, clinical examination, radiographs in two planes and visual analogue scales (VAS). The results were evaluated using established scoring systems. On the Gartland and Werley scale 75% of the results were good or very good, 63% according to Castaing. In general, there was no statistically significant difference between the results of this study and those of 1983/85. It could be demonstrated that there was a relationship between arthritis as a late complication and the existence of an intra-articular step-off of at least 2 mm at implant removal. This also has a negative influence on the range of motion and strength. Radial shortening affects the functional result whereas a die-punch fragment does not. On VAS patients identified performance restriction and disability as the worst consequences of the accident; these criteria correlated best with the results of objective evaluations. In contrast, patients were more satisfied with the result of treatment than would be expected from the objective analyses. The overall results indicate that exact reduction was extremely important. Long-term follow-up showed that the use of the external fixator in the treatment of comminuted intra-articular fractures of the distal radius was an adequate method. Prospective and possibly multicentric studies would be required to investigate more detailed relationships between treatment and long-term results.

Adult↗
PubMed1992

[Language competence of 14-year-old adolescents in relation to their sociocultural origin: results from a logopedic study in the framework of the Basel kindergarten study].

Between 1986 and 1988 speech and language abilities of a representative sample of 341 fourteen-year-old Basle schoolchildren were assessed as part of the 2nd Follow-up examination of the Basle Kindergarten-study. The language and speech test consisted of retelling and writing two stories, one of them played by tape-recorder, the other by video recorder. In addition three established language tests (Mottier-, IMK- and KLI-speechtest) were used. The results show significant differences between Swiss children and children of Italian workers in different test parts. There are also differences between boys and girls and between social classes. The high proportion of children with language difficulties is alarming. Parts of the tests used in this study were found to be appropriate for a screening of speech and language abilities.

Adolescent↗
PubMed1981

Immunohistological analysis of Hodgkin's and Sternberg-reed cells: detection of a new antigen and evidence for selective IgG uptake in the absence of B cell, T cell and histiocytic markers.

To help clarify the origin and nature of Hodgkin's (H) and Sternberg-Reed (SR) cells, three different sets of experiments were performed. First, it was shown that cytoplasmic gamma, kappa, lambda occur not only in H and SR cells, but also in polymorphic tumor cells of epithelial, neurogenic, and lymphoid origin. Furthermore, human IgG that was injected i.v. into rats penetrated many rat liver cells, whereas injected human alpha 1-antitrypsin did not. Second, staining of frozen sections revealed that H and SR cells lack surface immunoglobulin and peripheral T-cell antigen. Third, an antiserum raised against the L 428 cell line (derived from Hodgkin's disease) and absorbed with human serum and normal cells did not react with any cells of tonsil tissue (lymphoid cells, histiocytes, and interdigitating reticulum cells), whereas it reacted strongly with the L 428 cell line cells and with H and SR cells of 10 different cases. In all ten cases, the antiserum stained the surface of H and SR cells; in two cases, it also stained the nucleoli and some chromatin spots in H and SR cells. The results obtained in these experiments indicate that H and SR cells are not closely related to lymphoid cells, histiocytes, or interdigitating reticulum cells. The findings also suggest that H and SR cells express one or more antigens that have not yet been detected on or in normal cells.

Animals↗
PubMedDate not supplied

The efficacy of L-Deprenyl in dogs with pituitary-dependent hyperadrenocorticism.

Ten dogs with pituitary-dependent hyperadrenocorticism (PDH) received 2 mg/kg of L-Deprenyl once daily for 6 months. Monthly patient assessment consisted of evaluation of the owner's daily observation protocol, a standardized owner questionnaire, physical examination, CBC, biochemical profile, determination of the urine cortisol/creatinine ratio (UC/C), low-dose dexamethasone suppression (LDDS) test, corticotropin releasing hormone (CRH) test, and adrenal ultrasonography. At the beginning and the end of the study, an adrenocorticotropic hormone (ACTH) stimulation test and computed tomography also were performed. Two dogs developed neurologic signs and 2 dogs developed acute pancreatitis. An increase in activity, decrease in polyphagia, and decrease in panting were reported by 6, 4, and 2 owners, respectively. Seven owners believed that water intake decreased, but this was confirmed in only 3 dogs. Water intake increased in 2 dogs and remained unchanged in 5 dogs. The condition of the hair coat and skin improved in 2 dogs, worsened in 3, and remained unchanged in 5. Urine specific gravity, urine osmolality, ACTH test results, UC/C, and adrenal gland size did not change significantly throughout the study. In 4 of 8 dogs, LDDS was abnormal at the start of the study but normal at the end of the study, and in 2 dogs, the opposite occurred. Marked individual variation was noted in the CRH test, with a tendency for smaller increases in ACTH toward the end of the study. A marked increase in hypophyseal tumor size occured in 4 dogs. Treatment with L-Deprenyl resulted in improvement, deterioration, and stagnation of clinical signs in 2, 4, and 4 dogs, respectively. The results of this study indicate that L-Deprenyl cannot be recommended as the sole treatment for canine PDH.

Adrenal Glands↗
PubMedDate not supplied

[Heroin-assisted treatment of opiate addicts--former and current research emphasis].

Heroin-assisted treatment has been examined broadly in Switzerland since 1994 within the context of scientific studies. The goal was to clarify the suitability of this treatment for opiate addicts whom previous therapy had failed to reach. Results of the initial research phase show that the target group could be reached for treatment extending 18 months with a satisfactory retention rate of 69%. The patients could improve their health and social situation during treatment and reduce illegal consumption of narcotics. Studies during the initial years primarily examined the viability of heroin-assisted treatment and its effects on the patients' psychosocial and somatic development. A second study phase ongoing since 1998 pursues the specific importance of medical and psychosocial treatment for patients' health and social development in heroin-assisted treatment. The focal point is the effort to optimise treatment of patients with comorbidity of psychiatric disorders and severe somatic diseases, particularly AIDS. Investigations carried out in Switzerland have been discussed broadly at an international level. Studies on heroin-assisted treatment are also being conducted at present in various countries. In future, co-operation should be further intensified with researchers on an international scale.

Adolescent↗