Biomedical subjects

J I Kuiper

Publications and source records attributed to J I Kuiper.

6 recordsLinked to original sources

PubMed2005

Serum markers of collagen metabolism: construction workers compared to sedentary workers.

BACKGROUND: Evaluation of causal relations between physical load and musculoskeletal disorders is hampered by the lack of knowledge as to the biological relevance of different loading parameters and the large variability between individuals. As indicators of molecular changes in the extracellular matrices of structures of the musculoskeletal system, biomarkers of collagen metabolism may provide important information on biological effects of physical load. The carboxyterminal propeptide of type I collagen (PICP) is a serum marker of synthesis and the carboxyterminal telopeptide region of type I collagen (CTx) reflects degradation of type I collagen. AIMS: To explore the feasibility of biomarkers of type I collagen metabolism as measures of the effects of physical load at tissue level. METHODS: Serum concentrations of PICP and CTx were assessed in a group of male construction workers involved in heavy manual materials handling (n = 47) and in a group of male sedentary workers (n = 49). RESULTS: Serum concentrations of both PICP and CTx seemed to be related to heavy physical work. The ratio PICP/CTx, illustrative of the effective metabolic changes, did not differ between the two groups. CONCLUSIONS: The higher turnover rate but similar effective synthesis may be indicative of an increased type I collagen content in the connective tissues as a result of adaptive remodelling in response to years of exposure to physical load. Further validation of these biomarkers is required with respect to dose-response relations and temporal associations between exposure to back load and biomarker concentrations.

Adult↗

PubMed2004

Associations between serum markers of collagen metabolism and spinal shrinkage.

OBJECTIVES: To explore whether serum concentrations of the carboxyterminal propeptide of type I collagen and the carboxyterminal telopeptide region of type I collagen as biomarkers of the metabolic condition of spinal tissues are associated with spinal shrinkage as a measure of tissue response to physical loading. DESIGN: Association of biomarker concentrations in blood and spinal shrinkage in healthy young nurses. BACKGROUND: Certain biomarkers of type I collagen metabolism may be considered potential instruments to assess the biochemical condition of spinal tissues and alterations thereof in response to physical loading. Correlation of the serum concentrations of the biomarkers with spinal shrinkage, as a measure of the response of spinal tissues to physical loading, provides information on the validity of the biomarkers. METHODS: Concentrations of biomarkers of type I collagen synthesis and degradation have been monitored during a period of six months in 25 young nurses. Spinal shrinkage was assessed on a representative working day and related to shrinkage on a rest day. RESULTS: Larger relative spinal shrinkage was associated with a lower rate of collagen turnover and a higher relative synthesis. CONCLUSIONS: These results support the assumption that biomarkers of type I collagen metabolism are associated with structural and material properties of spinal tissues.

Adult↗

PubMed2001

Assessment of short-term physical loading of the back: is serum keratin sulfate an appropriate biomarker?

STUDY DESIGN: A prospective experimental study. OBJECTIVES: To investigate the potential of serum keratan sulfate (KS) as an indicator of biochemical changes in intervertebral discs induced by physical loading of the back. BACKGROUND: By providing objective information on exposure and effects at the tissue level, biomarkers may enable us to improve our understanding of the intermediate steps between exposure to physical loading and the occurrence of back disorders. Serum KS has been proposed as a potential biomarker of the molecular changes in intervertebral discs that occur because of physical loading and are a potential cause of back disorders. METHODS AND MEASURES: Thirty-two nonimpaired men volunteers with a mean age of 22.5+/-2.3 years participated in the experimental condition, a manual lifting task, as well as in the control condition, lying on the back. Serum KS levels were measured immediately before and after both conditions, as well as 24 hours and 1 week later. RESULTS: No significant changes in serum KS levels were found after exposure to physical loading (mean SD serum KS before, 287.4+/-83.9 ng/mL; immediately after, 279.5+/-65.5 ng/mL; 24 hours after, 266.6+/-71.9 ng/mL; and 1 week after, 268.9+/-79.3 ng/mL), and no significant changes were found after lying on the back for 8 hours (mean+/-SD serum KS before, 273.0+/-94.3 ng/mL; immediately after, 261.6+/-68.9 ng/mL; 24 hours after, 277.3+/-68.9 ng/mL; and 1 week after, 274.5+/-68.5 ng/mL). CONCLUSIONS: These results indicate that the serum KS level is not suitable as a biomarker of the effects of short-term physical loading of the back induced by a manual lifting task.

Adult↗

PubMed1998

Keratan sulfate as a potential biomarker of loading of the intervertebral disc.

STUDY DESIGN: A review of the literature. OBJECTIVE: To investigate the potential of serum levels of keratan sulfate as a biomarker of the effects of loading of the spine. SUMMARY OF BACKGROUND DATA: Exposure to mechanical loading of the spine causes changes in metabolism of intervertebral discs, eventually leading to accelerated disc degeneration. This process is characterized by the degradation of proteoglycans, which is reflected by an increase in the blood level of proteoglycan components. The serum level of keratan sulfate, an epitope present on these proteoglycan components, has been suggested as a marker of changes in metabolism of cartilaginous tissues. METHODS: A review of the literature on serum keratan sulfate levels in relation to degenerative changes in cartilaginous tissue. RESULTS: In a number of studies keratan sulfate in serum was reported to be related to degeneration of articular cartilage in patients with osteoarthritis. In addition, massive and rapid degradation of intervertebral discs was determined to result in a large rise in serum keratan sulfate levels. Whether degenerative changes of intervertebral discs induced by mechanical stress also cause a detectable increase in serum keratan sulfate should be subjected to further investigation. CONCLUSION: Quantification of keratan sulfate in serum offers a promising measure for the early effects of mechanical loading of the spine, but research is needed for validation.

Biomarkers↗

PubMed1995

Lorry drivers' work stress evaluated by catecholamines excreted in urine.

OBJECTIVES: To evaluate lorry drivers' work stress by measurement of adrenaline and noradrenaline excreted in the urine, and to find out which factors in their working situation are related to the excretion rates of these catecholamines. METHODS: The urinary excretion of adrenaline and noradrenaline of 32 lorry drivers, who also had loading and unloading activities to perform, was studied for one working day and one rest day. Each driver was asked to provide six urine samples on both days. RESULTS: For all samples, except the first (overnight) sample, the excretion rates of both catecholamines on the working day were higher than those on the rest day. Hierarchical multiple regression analyses were carried out to find out which factors in the drivers' working situation were related to the excretion rate of the working day. The excretion rate of adrenaline on the rest day, age, and psychosomatic complaints were positively related to the excretion rate on the working day (all P < 0.05). Body mass index and physical workload during loading and unloading were positively related to noradrenaline excretion rate (both P < 0.01). Psychosocial job strain did not significantly contribute to the proportion of variance explained in the excretion rates of both catecholamines. CONCLUSIONS: The excretion rates of adrenaline and, especially, noradrenaline on the working day were higher than those found in earlier studies among professional drivers and insufficient recovery took place after the work was ended. The only association between excretion rate on the working day and work stressors was found for noradrenaline and physical workload. The drivers' sympathoadrenal medullary reactivity to everyday work demands shows the characteristics of sustained activation.

Adult↗

PubMed1995

Sources of variance in exposure to nonneutral trunk postures in varying work situations.

OBJECTIVES: The purpose of this study was to estimate the different components of variance in exposure to nonneutral trunk postures. METHODS: The percentages of worktime spent in trunk flexion and trunk rotation or lateroflexion during 10-min observation periods were used as primary measures in analyses of variance to separate the total variance in its components. For two occupational groups six observation periods were selected per worker, and for four other groups 10 periods were used. Most of the 35 subjects were not restricted to one workplace, and they performed dynamic work while being observed. RESULTS: The variance within workers contributed around 80% to the total variability of exposure to both unfavorable postures. These results indicate that it is difficult to achieve an unbiased estimate of exposure to postural stress for individual workers who perform dynamic tasks in varying work situations. CONCLUSIONS: The results indicate that it is difficult to achieve an unbiased estimate of exposure to postural stress for individual workers who perform dynamic tasks in varying work situations. Measurement strategy for exposure assessment requires many repeated observations per worker.

Adult↗