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Biomedical subjects

K J Obrant

Publications and source records attributed to K J Obrant.

At least 37 records · Page 2Linked to original sources
PubMed1999

Ethanol and its effects on fracture healing and bone mass in male rats.

Operatively induced, standardized tibia fractures in 42 10-week-old male rats were fixed with intramedullary nails. 21 of the rats were fed liquid containing 15% ethanol. 5 weeks after inducing the fracture, the rats were killed and the total body bone mineral density (BMD) was analyzed with the DEXA technique, and the mechanical properties of the fractured and the unfractured tibiae as well as the ipsi- and contralateral femoral shaft and femoral neck were tested. The rats given a liquid containing 15% ethanol were found to have significantly lower total BMD and total calcium than the controls. We also found a significantly lower bending moment and bending stiffness both in the fractured and unfractured tibiae among rats fed on ethanol. The energy absorption until refracture was less in rats fed on ethanol. Posttraumatic osteopenia was present, as judged by the mechanical tests of the ipsilateral femoral shaft and the femoral neck in all animals. There was no difference in this respect between the animals fed on ethanol and the controls. We found that ethanol disturbs bone metabolism which reduces the mechanical properties of the tibiae and femora of rats, but the healing process of an induced tibial shaft fracture was not affected.

Absorptiometry, Photon↗
PubMed1998

Balance and gait performance in an urban and a rural population.

OBJECTIVE: To compare the differences in standing balance and gait performance between two populations, correlated with age and physical activities of daily living. DESIGN: A cross-sectional study. SETTINGS: Malmö, the third largest city in Sweden, and Sjöbo, a typical agricultural community 60 km east of Malmö. PARTICIPANTS: Participants were 570 men and women from the urban community (urban) and 391 from the rural community (rural), born in 1938, 1928, 1918, and 1908, and women born in 1948. The two cohorts were subdivided into true urbans, who had lived only in the city (n = 269), and true rurals, who had never lived in a city (n = 354). MEASUREMENTS: Information about workload, housing, spare time activities, medication, and illness during different decades of life was gathered using two questionnaires. The first questionnaire was sent to the home after agreement to participate, and the second was presented at the test session. The clinical measurements were standing balance, gait speed, and step length. RESULTS: The urban subjects had significantly (P < .001) impaired balance compared with rural subjects. This difference increased with increasing age. The urban subjects walked faster than the rural subjects (P < .001), and the urban subjects used fewer steps than their rural counterparts (P < .001). Spare time activities had a significant influence on the above tests, but, except for gait velocity (P = .011), workload was of minor importance according to analysis of covariance. CONCLUSION: Background factors such as usual daily activities of living and lifestyle seem to be of importance when evaluating and comparing different populations with respect to their balance and gait performance.

Adult↗
PubMed1998

Bone mineral density assessed by quantitative ultrasound and dual energy X-ray absorptiometry. Normative data in Malmö, Sweden.

We measured bone mineral density (BMD) in 128 men and 143 women, aged 22-90, by dual energy X-ray absorptiometry (DEXA) and quantitative ultrasound (QUS). We found reduced bone mineral density in relation to age as measured both by DEXA and QUS. There was a correlation between 0.28 and 0.52 in men and between 0.53 and 0.77 in women when comparing DEXA and QUS measurements. When including only persons with low bone mass, the correlation was less.

Absorptiometry, Photon↗
PubMed1997

Effects of clodronate on cortical and trabecular bone in ovariectomized rats on a low calcium diet.

The aim of this study was to evaluate the contribution of a low calcium diet to the cortical and trabecular osteoporosis seen in ovariectomized rats after 7 weeks on a low calcium diet and to investigate the effects of the bisphosphonate clodronate on this development of osteoporosis. Thirty-six mature, female Wistar rats were randomized into four groups: Ovx-B (bisphosphonate) and Ovx-C (control) were ovariectomized, and Sham-Ca (low calcium) and Sham+Ca (normal calcium) were sham operated. The first three groups were fed a low calcium diet (0.01%) and Sham+Ca normal rat chow (Ca 1.1%). The Ovx-B received 10 mg/kg s.c. clodronate daily for nine weeks, and Ovx-C, Sham-Ca, and Sham+Ca received the same volumes of saline. Bone mineral turnover measured as 85Sr-uptake was increased in all low calcium groups compared to Sham+Ca. The Sham+Ca femora had higher dry weight and ash weight than the other groups, and Ovx-C had higher dry weight compared with Ovx-B and Sham-Ca. Calcium content was lower in both Ovx groups compared to both Sham groups. Magnesium was lower in all groups compared to Sham+Ca and higher in Ovx-B compared with Ovx-C. In the femoral shaft, Sham+Ca had significantly higher ultimate bending moment, energy absorption, and deflection compared to the other three groups. Ultimate bending moment was higher in Sham-Ca than in Ovx-C. Stiffness was increased in both Sham+Ca and Ovx-B compared to Ovx-C. The maximum stress in the femoral midshaft was higher in Sham+Ca than in the other groups, and higher in Ovx-B than in Ovx-C. Histomorphometry showed increased medullary area in all low calcium groups compared to Sham+Ca and larger cortical area in Sham+Ca and Ovx-B compared to Ovx-C. Compared to Sham+Ca the trabecular bone volume was decreased to 30% in Sham-Ca and to 9% in Ovx-C, but was unchanged in Ovx-B. The low calcium diet generally increased bone mineral turnover and reduced the tibial bone volume. Femoral changes led to a reduction of cortical fracture strength and maximal stress. Ovariectomy in addition to a low calcium diet reduced femoral strength even more. Daily injections of clodronate to ovariectomized rats on a low calcium diet increased femoral shaft stiffness and maximum stress, and clodronate preserved both trabecular and cortical tibial bone volume completely.

Animals↗
PubMed1997

What is the impact of osteoporosis?

A body of evidence points towards a close connection between susceptibility to fractures and osteoporosis. The incidence of osteoporotic fractures, both in absolute figures and in age-specific figures, has increased worldwide throughout this century. Although some reports show that the age-specific incidence is levelling-off, there will be a continuously increasing number of individuals with such fractures that will have implications from an economical point of view not only for the affected individual but for society as a whole. The outcome after such fractures, especially those of the hip, is by no means always favourable, partly due to insufficient results after orthopaedic treatment and partly due to an already high comorbidity. Therefore, trying to prevent osteoporotic fractures by non-pharmacological or pharmacological regimens is of utmost importance.

Aged↗
PubMed1997

Effect of intensive training on lower leg structural strength: an in vivo study in ovariectomized rats.

The aim of this study was to investigate the effect of training on the in vivo tibial structural strength during the development of post-ovariectomy osteoporosis. Seventeen mature Wistar rats (215 g) were ovariectomized and randomized into two groups. The sedentary control group was kept cage confined, while 3 days postoperatively the trained group started treadmill running with high intensity for 1 h 5 days a week. All were given a low calcium diet (Ca 0.01%). After 8 weeks the animals were anaesthetized and the right lower legs fractured during muscle contraction in three-point ventral bending. The left legs were fractured at the same level after removal of all soft tissues. Histomorphometry of the meta- and diaphysis of the distal tibiae was performed. Weight-gain was higher in sedentary (108 g) than in trained (61 g) rats (P<0.0001). There were no significant differences in mechanical results between the groups at in vivo or in vitro fracture. Correcting for weight-gain differences did not change these results. Histomorphometry showed no differences between the groups. Corticosterone was higher in trained than in sedentary rats (P<0.02), and corticosterone may have had a negative influence both on muscle and bone. The study could not show an effect of high intensity training in the early phase after ovariectomy on in vivo or in vitro fracture strength.

Animals↗
PubMed1996

Bone mineral density in athletes during and after career: a comparison between loaded and unloaded skeletal regions.

Bone mineral density (BMD) was measured in the upper part of the skull, the femoral neck, and the total body by dual energy X-ray absorptiometry in 56 male and 33 female active athletes, 18-40 years of age, together with 64 male ex-weight lifters, 35-79 years of age. The active athletes were compared with 41 male and 54 female controls, the ex-weight lifters with 133 male controls. The purpose of the study was to see if BMD in the upper part of the skull, a region virtually unaffected by physical load, is different in athletes and controls. The male athletes had a 3% higher BMD for the total body and 12% for the hip, whereas the BMD for the upper part of the skull was 10% lower than controls. Corresponding BMD values for the female athletes were 4% higher for total body and 10% for the femoral neck, and the upper part of the skull was 7% lower than in controls. After 65 years of age there was no difference in BMD comparing ex-weightlifters and controls. Using a constructed ratio BMD total body to BMD upper part of the skull, the ex-weight lifters had 10% higher values also after age 65. It appears that bone mass is higher in weight-loaded areas and lower in an unloaded region, such as the upper part of the skull, in exercising athletes. After cessation of the active career, the bone mass approaches that of the controls and after 65 years of age, no difference was found comparing ex-weight lifters and controls. Due to the apparent bone mass shift from unloaded skeletal regions to loaded skeletal regions that seems to take place in active athletes, the constructed ratio, BMD total body to BMD upper part of the skull, seems to discriminate the influence on the skeleton in a more sensitive way than measuring the BMD in defined skeletal regions on their own. By using this constructed ratio, the influence on bone mass of physical exercise early in life is also detectable at older ages.

Adult↗
PubMed1996

Changes of bone mineral mass and soft tissue composition after hip fracture.

The aim of this prospective longitudinal study was to measure prospectively the bone mineral density (BMD) and anthropometric variables after a hip fracture. In particular, we studied changes in the BMD in both the injured and uninjured hips, and examined if the postoperative mortality rate and complications, including pseudarthrosis of the fracture and late segmental collapse of the head of the femur, could be predicted by early bone mass measurements. The bone mineral density and the body composition were measured with dual energy X-ray absorptiometry in 102 consecutive hip fracture patients, 31 men and 71 women, with a mean age of 74 and 79 years, respectively. All cases were operated on within 3 days. The measurements were undertaken within 10 days after the fracture, after 4 and after 12 months. The BMD of the hip fracture cases decreased, especially in the lower extremities where the patients lost 7%, during the first year after the fracture. The patients also lost lean body mass (5%) but gained fat (11%) during the same period. They lost significantly more bone mass in the fractured hip than in the uninjured hip (p < 0.05). No difference was found between those patients who survived and those who died within 2 years after their hip fracture in neither the initial measurement nor in the follow-up measurements. Also, we found no difference between those patients whose hip fracture healed and those who developed late segmental collapse or pseudarthrosis. In conclusion, osteoporotic hip fracture cases lose bone mass at an increased rate, especially in the fractured hip. Also, their soft tissue composition changes, gaining fat while losing muscle mass. Furthermore, it seems that early bone mineral measurements cannot predict postoperative failures or postoperative mortality.

Aged↗
PubMed1996

Femoral neck geometry and radiographic signs of osteoporosis as predictors of hip fracture.

A total of 125 consecutive hip fracture patients were investigated regarding hip geometry. There were 33 men of mean age 76 +/- 10 years, and 92 women of mean age 78 +/- 9 years. Patients with previous hip surgery were excluded. Hip geometry (hip-axis length, width of collum femoris, and femoral shaft and neck-shaft angle) were registered on both plain radiographs and DEXA scans performed within 2 weeks after fracture. On the radiographs, the calcar femorale, the Singh index, and the femoral neck index (FNI) were also calculated and compared with earlier published values of bone mineral density hip in the hip fracture patients. The fracture cases were compared with controls, 192 DEXA scans and 163 radiographs, in patients without hip surgery or known hip disease. As measured on the DEXA scans we found a wider collum femoris and a wider femoral shaft in both the male and female fracture cases, compared to controls. Also, the fracture cases showed signs of osteoporosis as measured by the calcar femorale, the Singh index, and the femoral neck index. These measurements showed good correlation with bone mineral density of the hip as measured by the DEXA scans.

Absorptiometry, Photon↗
PubMed1995

Assessment of biochemical markers of bone metabolism in relation to the occurrence of fracture: a retrospective and prospective population-based study of women.

We have in a population-based setting evaluated biochemical markers of bone metabolism in 328 women, aged 40-80 years, and related it to contents of bone mineral measurements and the retrospective and prospective presence of fracture. The participants were recruited from the city population files. Serum samples for analysis of osteocalcin (Oc), procollagen I carboxy-terminal extension peptide (PICP), and carboxy-terminal telopeptide of type I collagen (ICTP) were taken, and forearm bone mineral content (BMC) was measured by single photon absorptiometry (SPA). Fracture history was recorded, and the information was verified and supplemented from both radiologic and orthopedic files. Five years later the registration of fractures was repeated. At the initial investigation, Oc was 23% lower in women who had sustained a fracture (n = 37) within 6 years before measurement (6.3 +/- 3.6 microgram/l vs 8.2 +/- 4.2 microgram/l (p = 0.006)), after adjusting for age and BMC difference. PICP and ICTP were not different from values in the women without fracture. However, in women aged 70-80 years with a fracture sustained during the previous 6 years, PICP was lower (128 +/- 32 microgram/l vs 144 +/- 34 microgram/l, p = 0.046). Oc and ICTP were significantly correlated to age and BMC (Oc-age r = 0.36, Oc-BMC r = -0.31, ICTP-age r = 0.44, ICTP-BMC r = -0.24). The correlations of PICP were weaker. Prospectively, logistic regression gave an odds ratio (OR) of 1.8 (p = 0.015) for a low PICP and fracture susceptibility, at a change of 1 SD, independent of age and BMC. In the age bracket 70-80, the odds ratio was 2.4 (p = 0.036). The odds ratio for ICTP, independent of age and BMC, was 1.9 (P = 0.043) for 1 SD decrease and subsequent fracture risk. We concluded that women who had sustained at least one recent fracture had an altered bone turnover with decreased bone formation but an unaltered resorption. Women with retrospectively registered fractures also sustained subsequent fractures. A decrease from the mean of the collagen markers PICP and ICTP was associated with an increased risk for future fracture. Utilizing these biochemical markers of bone metabolism in a female population, PICP and ICTP had a similar influence on the risk of future fracture as forearm BMC (OR = 1.6, p = 0.03).

Adult↗
PubMed1995

Indicators of bone formation in weight lifters.

Physical activity has been suggested to be one of the determinants of bone turnover and to prevent age-related bone loss. To examine this we measured the serum levels of osteocalcin (bone Gla-protein, BGP), C-terminal procollagen peptide (PICP), serum alkaline phosphatase, bone-specific alkaline phosphatase, and S-calcium as indices of bone formation in 19 actively performing and 15 ex-lifters. All were nationally or internationally ranked male athletes. Their values were compared with those from 38 age- and gender-matched controls. Actively performing weight lifters had 35% higher (P < 0.05) serum concentration of osteocalcin than the controls. The ex-lifters did not differ from the age-matched controls. Also serum calcium was elevated in active lifters (6%) (P < 0.01) but not in ex-lifters. No difference was found for serum-ALP, B-ALP, or PICP in either of the groups. Our study indicates that in addition to an already documented and well-known higher bone mineral density in heavily exercising athletes, they have an indication of higher bone formation as measured by biochemical markers. In athletes who have retired from competitional training, however, the bone formation does not differ from that of more sedentary controls.

Adult↗
PubMed1995

Is bone mineral density advantage maintained long-term in previous weight lifters?

This cross-sectional study was done in order to ascertain whether there is a lifelong beneficial effect on bone mineral density (BMD) of early, long-lasting, and intense physical exercise. Forty-eight male ex-weight lifters, mean age 64 years (range 50-79) participated. They had followed a training program of an average of 10 hours/week (range 4-20) for an average of 13 years (range 1-34). They had all retired from competitive sport an average of 30 years (range 7-50) ago. Sixty-six age-matched volunteers served as controls. The bone mineral density (BMD, areal density, g/cm2) in the total body, spine, and hips and the fat content and lean body mass were measured with the LUNAR DPX bone mass scanner. In ex-weight lifters 50-64 years of age, the BMD was greater than in controls. After 65 years, no difference was found between the former weight lifters and their controls.

Absorptiometry, Photon↗
PubMed1995

Serum osteocalcin increases during fracture healing in elderly women with hip fracture.

The purpose of this study was to define the bone metabolic properties during the postfracture period in elderly women with hip fracture. Osteocalcin (Oc), a marker of bone formation, was measured in 58 women with hip fracture (77 +/- 7 years) admitted to the hospital from their own homes. Serum samples were taken on average 5 h (range 1-21) from fracture and at follow-up, on average 4.6 months later. Comparison was made with 58 age-matched (79 +/- 5 years) women. Women with hip fracture had initially 30% lower Oc levels compared to the controls (p = 0.0001). The Oc level was independent of time elapsed from trauma, within 18 h, after which the level further decreased. At follow-up, Oc showed a 44% increase (p = 0.0001) and had reached the level of the controls, but not beyond it. A concomitant, but less marked increase was noted for alkaline phosphatase (ALP) (p = 0.0001). We conclude that although the bone formation, as assessed by Oc, is apparently lower in elderly women who sustain a hip fracture, the ability to induce a fracture response, with an increased bone turnover during fracture healing is intact. Subsequently, it is essential that a time perspective is applied, as the bone metabolic changes in patients having sustained a fracture are related to the time elapsed from fracture.

Aged↗
PubMed1995

Micromotion of the acetabular component and periacetabular bone morphology.

The quality of the periacetabular bone might be an explanation for the increase in the rate of socket loosening seen radiographically in patients with rheumatoid arthritis as compared with patients with osteoarthrosis. Early implant micromotion, as measured by roentgen stereophotogrammetric analysis, is of predictive value with regard to long time retention. For uncemented porous sockets, the initial fixation might be decisive for the degree of bone ingrowth. Roentgen stereophotogrammetry was used to study cemented Charnley acetabular components in 32 hips with rheumatoid arthritis and 30 hips with osteoarthrosis, and uncemented Harris-Galante acetabular components in 19 hips with osteoarthrosis. Micromotions as long as 24 months after surgery were related to the periacetabular cancellous bone quality, as assessed by histomorphometric methods from samples taken during surgery. Acetabular components migrated more in hips with rheumatoid arthritis than in those with osteoarthrosis (p < 0.04). Hips with rheumatoid arthritis had approximately 4 times more nonmineralized bone than hips with osteoarthrosis (p < 0.0002). However, within each diagnostic group, no correlation was found between migration and the degree of mineralization (r < or = 0.24, p > or = 0.07). Migration of uncemented acetabular components did not correlate with the histomorphometric variables (r < or = 0.20, p > or = 0.42). Histomorphologic characteristics of the periacetabular trabecular bone do not seem to be of importance for acetabular component micromotion.

Acetabulum↗
PubMed1995

Migration of the Charnley stem in rheumatoid arthritis and osteoarthritis. A roentgen stereophotogrammetric study.

Migration of 65 Charnley stems implanted with modern cementing techniques was studied by roentgen stereophotogrammetry. There were 25 patients with rheumatoid arthritis (RA) and 40 with osteoarthritis (OA) followed up for two years. In 43 cases a bone sample for histomorphometric analysis was obtained from the femur during the operation. In 22 cases the mean subsidence of the prosthetic head was 0.40 mm and in 20 the mean posterior migration was 1.25 mm. There was no difference in migration between the two diagnostic groups (p = 0.8) after adjusting for variations in gender, age and weight. Male gender was associated with increased subsidence (p = 0.006). Histological examination showed that the RA series had more osteoid surface (p = 0.04), but neither this, nor any of the other histomorphometric variables, influenced migration. These results suggest that, unlike the acetabular socket, the cemented Charnley femoral component is equally secure in osteoarthritis and in rheumatoid arthritis, and that its initial fixation is not influenced by the quality of the local cancellous bone. Our results provide data with which the early performance of new prosthetic designs and fixation methods can be compared.

Analysis of Variance↗
PubMed1994

Muscle contraction increases the in vivo structural strength to the same degree in osteopenic and normal rat tibiae.

The increase in structural capacity due to muscle contraction in the lower leg was investigated in osteopenic and normal rats. Osteopenia was induced by ovariectomy combined with a low-calcium diet (0.01%). The control rats were sham operated and fed a diet containing 1.1% calcium. After 7 weeks the right lower leg of all animals were fractured in three-point ventral cantilever bending during muscle contraction induced by electrical stimulation of the ischiatic nerve. The left tibiae were resected and fractured as each animal's control. During muscle contraction in vivo, the ultimate bending moment, energy absorption, bending stiffness, and deflection were significantly lower in the osteopenic than in the sham-operated animals. However, the increase in mechanical parameters due to muscle contraction comparing the in vivo and resected tibiae in each animal were equally high in the osteopenic and sham-operated animals. Ultimate bending moment in the resected tibiae was 10% higher in the sham-operated animals compared with the ovariectomized, proving mechanically weaker tibiae in the osteopenic rats. In accordance with this, the medullary area of the osteopenic rats was 46% larger in the distal tibial diaphysis, and the ultimate stress the tibiae could withstand was 15% lower in the osteopenic compared with the sham-operated rats. The trabecular bone volume in the distal tibial metaphysis of the osteopenic rats was reduced by 70% compared with the sham operated. This study shows that muscle protection against fracture can be substantial in osteopenic tibia and that it is of the same magnitude as in rats with normal bone mass.

Animals↗
PubMed1994

Energy-dispersive X-ray microanalysis of the bone mineral content in human trabecular bone: a comparison with ICPES and neutron activation analysis.

To evaluate the accuracy of bone mineral composition determination by electron microprobe analysis (EDX) the measurements have been compared to instrumental neutron activation analysis (INAA) and chemical analysis (ICPES). Bone specimens from five femoral heads were used. The trabecular content of calcium (Ca) and phosphorus (P) was analyzed by the three different methods. The EDX method allows for a microstructural analysis of intact, methylmetacrylate-embedded, undecalcified bone and the measuring points can thus be distinctly identified centrally in each trabecula. The analysis yielded 25.8 +/- 0.7 wt % Ca and 10.5 +/- 0.1 wt % P, compared with 22.2 +/- 0.5 and 23.0 +/- 1.0 wt % Ca, and 9.83 +/- 0.21 and 10.02 +/- 0.44 wt % P for INAA and ICPES, respectively. The EDX analysis was calibrated by consecutive measurements of a hard, pressed tablet of hydroxyapatit of known content. The mean Ca content deviated with -0.38 wt % from the given content and P with -0.89 wt %. We could not verify any particular interference from the embedding procedure, however, it is possible that the relatively lower P content still may reflect this. The magnesium (Mg) concentration was 0.31 +/- 0.02 wt % by EDX and 0.26 +/- 0.02 wt % by INAA. The EDX analytical method provides a useful tool for simultaneous elemental quantification in bone. It has the advantage of permitting the use of regular bone biopsy material and thus allowing for a unique microstructural evaluation of the degree of mineralization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗