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Biomedical subjects

A Ohlin

Publications and source records attributed to A Ohlin.

At least 19 recordsLinked to original sources
PubMed1999

Bone resorbing activity released from zymosan-activated mouse peritoneal macrophages--the role of prostanoids and interleukin-1.

OBJECTIVE: To study the effect of zymosan on the release of osteoclast stimulating activity from macrophages. MATERIALS: Calvarial bones from neonatal mice and peritoneal macrophages were incubated in the absence and presence of zymosan for 72 h and supernatants harvested for subsequent analysis of bone resorbing activities and prostaglandin concentration. METHODS: Bone resorption was assessed in vitro by analysing the release of 45Ca and 3H from neonatal mouse calvarial bones prelabelled in vivo by injections of [45Ca]CaCl2 or [3H]-proline. Prostaglandin E2 (PGE2) and I2 (PGI2) were analyzed using radioimmunoassays. RESULTS: Supernatants from macrophages treated with zymosan stimulated the release of 45Ca and 3H. The amount of bone resorbing activity present in the macrophage supernatants was dependent on the concentration of zymosan (0.1-100 microg/ml), as well as the number of macrophages present. The 45Ca release induced by zymosan treated macrophages was inhibited by three different inhibitors of osteoclastic bone resorption (calcitonin, acetazolamide, amino bisphosphonate). The bone resorbing activity released by the zymosan-activated macrophages was lost after ultrafiltration using a filter with a molecular weight cut off of 30,000 Daltons, but retained when using a filter with a cut off of 3000 Daltons. Time-course studies of the production of bone resorbing activity in macrophages showed that activity increased during the first hour of exposure to zymosan and then reached a plateau for 96 h. PGE2 and PGI2 release from macrophages was increased during the first three hours of exposure to zymosan. This prostanoid production, together with bone resorbing activity, was abolished by indomethacin. The bone resorbing activity present 3-72 h after zymosan exposure, however, was not inhibited by indomethacin. Bone resorption stimulated by conditioned media from zymosan treated macrophages after 3 h was inhibited by 60-75% in the presence of anti IL-1alpha, 0-20% by anti IL-1beta, and completely by antisera neutralizing both IL-1alpha and IL-1beta. In addition, an IL-1 receptor antagonist abolished the stimulatory effect of conditioned media from zymosan treated macrophages. CONCLUSIONS: These data indicate that treatment of mouse peritoneal macrophages with zymosan results in production of activities capable of stimulating bone resorption in vitro. The activity released initially appears to be due to a zymosan induced burst of prostanoid production, while the activity released during prolonged exposure to zymosan is due primarily to IL-1alpha.

Animals↗
PubMed1999

Spatial facilitation of motor evoked responses in monitoring during spinal surgery.

During spinal cord monitoring, motor responses in the tibialis anterior muscles were recorded on transcranial electrical stimulation of the motor cortex. In order to facilitate the responses, the cortical stimulus was preceded by a train of stimuli to the foot sole within the receptive field of the withdrawal reflex of the tibialis anterior muscle. This cutaneous input provides a spatial facilitation of the cortically elicited response. When the stimulus interval was 50-100 ms, large and reliable responses were seen in most cases.

Adolescent↗
PubMed1998

Gutta-percha-stimulated mouse macrophages release factors that activate the bone resorptive system of mouse calvarial bone.

This study investigated the capacity of macrophages exposed to gutta-percha particles to produce factors affecting bone metabolism. Peritoneal mouse macrophages were isolated and incubated with and without gutta-percha particles, and the supernatants were assessed for bone resorbing activity by adding macrophage-conditioned media to cultures of neonatal mouse calvarial bones. Bone resorption was measured by mineral mobilization (45Ca release) and matrix degradation (3H from [3H]proline labelled bones). The results showed that supernatant from gutta-percha-stimulated macrophages enhanced bone resorption. This effect was related to the amount of gutta-percha, and the concentration and time of exposure to the conditioned media. Stimulated macrophages released enhanced amounts of prostaglandins E2 and I2; however, indomethacin, which inhibits the prostanoid response, had no effect on bone resorbing activity. The stimulatory effect on bone resorption was inhibited by calcitonin, interleukin-1 receptor antagonistic protein, and by antiserum neutralizing mouse interleukin-1alpha(IL-1alpha), but not by anti-IL-1beta. Filtration experiments revealed that the molecules involved in the resorption activity had an apparent molecular weight between 3000 and 30,000 Da. These experiments show that mouse peritoneal macrophages, when exposed to gutta-percha particles, release factors which have a bone resorbing activity that is primarily due to enhanced production of IL-1alpha.

Animals↗
PubMed1998

Bacteria inhibit biosynthesis of bone matrix proteins in human osteoblasts.

The effect of extracts from Staphylococcus aureus and Staphylococcus epidermidis on bone matrix production were assessed by analyzing the biosynthesis of osteocalcin and Type I collagen in a human osteoblastic osteosarcoma cell line (MG-63). In MG-63 cells, extracts from Staphylococcus aureus and Staphylococcus epidermidis decreased 1,25(OH)2-vitamin D3 stimulated osteocalcin biosynthesis, and insulin-like growth factor I induced production of Type I collagen in a concentration dependent manner. The basal rate of osteocalcin and Type I collagen formation was unaffected by the bacterial extracts. The inhibitory effect of the bacteria on osteocalcin biosynthesis was seen after 24 hours of treatment and was maintained for at least 96 hours. The extracts of Staphylococcus aureus and Staphylococcus epidermidis enhanced prostaglandin E2 formation in the MG-63 cells. Abolition of the prostaglandin E2 response by treatment with indomethacin and flurbiprofen did not affect bacteria induced inhibition of osteocalcin production. Stimulation of osteocalcin biosynthesis by 1,25(OH)2-vitamin D3 was associated with a decreased rate of cell proliferation. The inhibitory action of the bacterial extracts was not linked to any inhibition of [3H]-thymidine incorporation into deoxyribonucleic acid. These data show that extracts of Staphylococcus aureus and Staphylococcus epidermidis have the ability to inhibit the biosynthesis of bone matrix proteins by a nonprostaglandin and noncytotoxic dependent mechanism and suggest that bone loss in inflammatory processes containing Staphylococcus aureus or Staphylococcus epidermidis may not be caused only by enhanced bone resorption but also by decreased bone formation.

Calcitriol↗
PubMed1997

Remodeling of the spinal canal deformed by trauma.

Computed tomography (CT) examinations and functional scores were evaluated in 28 patients with thoracolumbar fractures with intraspinal fragments, of whom 20 underwent operation. The cross-sectional area and the sagittal and frontal diameters of the spinal canal were measured after the injury, postoperatively, and at follow-up (mean, 6 years). The operative reduction significantly increased both diameter and area of the spinal canal. During follow-up, a further significant increase of the sagittal diameter and the area was noted, in both surgically and conservatively treated patients. There was no difference in remodeling between the groups. Six patients in the surgically treated group had neurologic deficits at admission, five had improved, and one remained unchanged at follow-up. The presence or absence of intraspinal fragments should not influence the treatment strategy per se in cases without neurologic signs.

Adolescent↗
PubMed1996

Factors related to body weight changes during and after pregnancy: the Stockholm Pregnancy and Weight Development Study.

The Stockholm Pregnancy and Weight Development Study is a prospective study of body weight changes in women, whose maternity unit charts were reviewed and who were then invited for a 1-year follow-up, including weigh-in sessions and questionnaires on dietary habits, physical activity and socio-demographic factors. Total weight gain during pregnancy was related to weight gain already during the first trimester. Women reporting previous weight cycling had slightly higher weight gain during pregnancy. Successful return towards pre-pregnancy weight was found more often in women with regular breakfast and lunch habits. Lactation had only a small effect on weight loss after delivery, independent of eating habits. Lack of physical activity was more common in women who had low lactation scores. Twenty-eight percent reported an increased interest in sweets during pregnancy; these women increased 1 to 2 kg more than others in weight during pregnancy. Postpartum weight retention was more affected by lifestyle changes during and after pregnancy than by factors before pregnancy.

Body Mass Index↗
PubMed1996

Cytokine-induced inhibition of bone matrix proteins is not mediated by prostaglandins.

Interleukin-1 (IL-1) and tumor necrosis factor (TNF), two pleiotropic cytokines produced in inflammatory processes, inhibit bone matrix biosynthesis and stimulate prostanoid formation in osteoblasts. In the present study, the importance of prostaglandin formation in IL-1 and TNF-induced inhibition of osteocalcin and type I collagen formation has been examined. In the human osteoblastic cell line MG-63, IL-1 alpha (10-1000 pg/ml), IL-1 beta (3-300 pg/ml) and TNF-alpha (1-30 ng/ml) stimulated prostaglandin E2 (PGE2) formation and inhibited 1,25(OH)2-vitamin D3-induced osteocalcin biosynthesis as well as basal production of type I collagen. Addition of PGE2 or increasing the endogenous formation of PGE2 by treating the cells with arachidonic acid, bradykinin, Lys-bradykinin or des-Arg9-bradykinin, did not affect osteocalcin and type I collagen formation in unstimulated or 1,25(OH)2-vitamin D3-stimulated osteoblasts. Four non-steroidal antiinflammatory drugs, indomethacin, flurbiprofen, naproxen and meclofenamic acid, inhibited basal, IL-1 beta- and TNF-alpha-stimulated PGE2 formation in the MG-63 cells without affecting IL-1 beta- or TNF-alpha-induced inhibition of osteocalcin and type I collagen formation. In isolated, non-transformed, human osteoblast-like cells, IL-1 beta and TNF-alpha stimulated PGE2 formation and concomitantly inhibited 1,25(OH)2-vitamin D3-stimulated osteocalcin biosynthesis, without affecting type I collagen formation. In these cells, indomethacin and flurbiprofen abolished the effects of IL-1 beta and TNF-alpha on prostaglandin formation without affecting the inhibitory effects of the cytokines on osteocalcin biosynthesis. These data show that IL-1 and TNF inhibit osteocalcin and type I collagen formation in osteoblasts independently of prostaglandin biosynthesis and that non-steroidal antiinflammatory drugs do not affect the effects of IL-1 and TNF on bone matrix biosynthesis.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1996

Comparative susceptibilities of human embryonic fibroblasts and HeLa cells for isolation of human rhinoviruses.

The recovery of human rhinovirus (HRV) from nasal washings and nasal and pharyngeal swabs from volunteers with naturally acquired colds was compared in different cell types. Human embryonic lung fibroblast (HELF) strain WI-38 (sensitivity, 61 to 84%) and HeLa-I, an HRV-susceptible HeLa clone (sensitivity, 86 to 94%), were the most sensitive cell types used. HELF-WI-38 cells showed a cytopathic effect earlier than the other cells used, and the different strains of HRV-susceptible HeLa cells varied in their sensitivities for HRV isolation. HRV was detected in a single cell type in 20 to 35% of the positive samples, suggesting that use of a combination of different HRV-susceptible cell lines is the best approach for the recovery of HRV. Although nasal washings tended to yield more HRV isolates than nasal and pharyngeal swabs, the two sampling methods were not found to be significantly different.

Cell Line↗
PubMed1995

Pregnancy as a risk factor for obesity: lessons from the Stockholm Pregnancy and Weight Development Study.

Pregnancy and maternal body weight development are intertwined in complicated patterns. In most studies, an increase in maternal body weight with age and parity has been reported. For women who develop obesity, pregnancies can, in retrospect, be identified as important triggering life events. In a retrospective analysis of 128 women at our Obesity Unit, 73% of these severely obese patients had retained more than 10 kg in connection with a pregnancy. For the general population, the effect of a pregnancy on future weight development is surprisingly difficult to predict. In The Stockholm Pregnancy and Weight Development Study, the effects of pregnancy on weight retention one year after delivery were studied in 1423 women. Data were collected retrospectively from routine pregnancy records and then extended prospectively 6 and 12 months after delivery. The mean weight retention associated with a pregnancy one year after delivery was estimated to about 0.5 kg, with a range of -12 to +26 kg. Fourteen percent of the women gained more than 5 kg. Weight increase during pregnancy was the strongest predictor for sustained weight retention 1 year later. Prepregnancy weight did not predict the weight development outcome. The lactation pattern had only a minor influence on weight development. Smoking cessation was an important predictor for sustained weight increase. More weight retention was observed in those women who reported a change in lifestyle as regarded eating habits, meal patterns, and physical activity, suggesting that eventual body weight after pregnancy is more determined by the changes in association with that particular pregnancy than with the lifestyle before.

Adolescent↗
PubMed1994

Complications after transpedicular stabilization of the spine. A survivorship analysis of 163 cases.

OBJECTIVES: The authors studied complications of transpedicular stabilization methods. SUMMARY OF BACKGROUND DATA: One hundred and sixty-three consecutive transpedicular stabilization procedures were performed between January 1987 and December 1991. The indications for stabilization were trauma (33 cases), metastatic spinal disorder (30 cases), spinal stenosis (33 cases), spondylolisthesis (27 cases), ankylosing spondylitis (6 cases), low back pain (22 cases), and miscellaneous (12 cases). METHODS: Patients records and the entire series of radiographs for each case were scrutinized by independent observers. All per- and postoperative complications, including implant loosening and fatigue, were recorded. Clinical and radiographic survivorship analyses of the implants were performed. RESULTS: Early complications were unusual and none were associated with permanent morbidity. The probability of not having the implant removed in the first postoperative year was 85%. There was a 40% risk of radiographic failure, defined as loosening or implant fatigue, at 6 months. The outcome was more favorable in cases in which anterior vertebral interbody fusion was also performed. CONCLUSIONS: Transpedicular fixation is a safe procedure with a low incidence of serious per- and early postoperative complications. The mechanical durability of transpedicular fixators used alone is a cause for concern.

Adolescent↗
PubMed1994

Trends in eating patterns, physical activity and socio-demographic factors in relation to postpartum body weight development.

'The Stockholm Pregnancy and Weight Development Study' was conducted to identify risk factors for postpartum weight retention, such as dietary habits, physical activity and socio-demographic factors. The body weight development of 1423 pregnant women was studied prospectively from the beginning of the pregnancy until 1 year postpartum. Data were collected from routine pregnancy records and from questionnaires 6 and 12 months postpartum. Mean weight retention 1 year postpartum was 0.5 kg compared with the prepregnancy body weight. A 'trend method' was constructed to identify a number of pre-defined major patterns of behaviour. The weight retention 1 year postpartum was greater in women who (a) increased their energy intake during and after pregnancy, (b) increased their snack eating after pregnancy to three or more snacks/d, and (c) decreased their lunch frequency starting during or after the pregnancy. Women who had retained > or = 5 kg 1 year postpartum were more seldom physically active in their leisure time throughout the study period compared with women with a smaller weight gain. Postpartum weight retention correlated negatively with the degree of physical activity in the second half year postpartum. These results indicate that postpartum weight retention is more affected by a change in lifestyle during, and above all after, pregnancy than by factors before pregnancy.

Adolescent↗
PubMed1994

Spectrum of activity of soluble intercellular adhesion molecule-1 against rhinovirus reference strains and field isolates.

The antiviral potency of soluble intercellular adhesion molecule-1 (ICAM-1; the major receptor for human rhinoviruses) was determined for a subset of American Type Culture Collection reference serotypes and field isolates of rhinovirus. The results indicate that soluble ICAM-1 exhibits a broad spectrum of activity against rhinoviruses and that field isolates have a sensitivity indistinguishable from that of laboratory strains.

Cell Adhesion Molecules↗
PubMed1994

Migration of acetabular components, inserted with and without cement, in one-stage bilateral hip arthroplasty. A controlled, randomized study using roentgenstereophotogrammetric analysis.

Twenty-one patients who had primary osteoarthrosis were managed with a bilateral total hip arthroplasty with insertion of a Charnley femoral component. In each patient, one hip was randomly allocated to have a Harris-Galante acetabular component inserted without cement, and the contralateral hip was treated with an all-polyethylene Charnley acetabular component fixed with cement. The clinical result was satisfactory in all patients. All forty-two hips were followed, with respect to migration of the acetabular component, with use of roentgenstereophotogrammetric analysis for a median of twenty-seven months (range, twenty-three to forty-nine months). Each patient served as his or her own control. Maximum migration in any direction was 1.7 and 2.1 millimeters, and maximum rotation was 2.2 and 2.0 degrees for the Harris-Galante and Charnley acetabular components, respectively. There was no significant difference in migration between the two designs of acetabular components (p = 0.98, p = 0.75, and p = 0.06 for the transverse, longitudinal, and sagittal axes, respectively). However, the Harris-Galante acetabular components rotated significantly more than the Charnley acetabular components around two of the three axes (p = 0.008, p = 0.08, and p = 0.03 for the transverse, longitudinal, and sagittal axes, respectively). The Charnley hip implant has been used clinically for a long time, with successful results. Comparison of new designs of implants with the Charnley prosthesis is therefore important. Roentgenstereophotogrammetric analysis provides a potential for detection of problems with fixation at an early stage rather than after long-term follow-up. No major difference in terms of skeletal fixation was found between the two designs of components after short to medium-term follow-up.

Acetabulum↗
PubMed1993

Tumor necrosis factors alpha and beta can stimulate bone resorption in cultured mouse calvariae by a prostaglandin-independent mechanism.

Human recombinant tumor necrosis factors alpha and beta (TNF-alpha and TNF-beta), at and above 1 ng/ml (approximately equal to 70 pM), caused a dose- and time-dependent enhancement of 45Ca release from neonatal mouse calvarial bones in vitro. In addition, TNF-alpha and TNF-beta (3-100 ng/ml) caused a dose-dependent stimulation of prostaglandin E2 (PGE2) formation in the calvarial bones. TNF-alpha also enhanced the biosynthesis of PGI2, as assessed by analysis of the stable breakdown product 6-keto-PGF1 alpha. The stimulatory actions of TNF-alpha and TNF-beta on PGE2 formation was maximal at 12 h. Indomethacin, flurbiprofen, and meclofenamic acid, three structurally unrelated nonsteroidal antiinflammatory drugs, abolished PGE2 biosynthesis induced by TNF-alpha and TNF-beta (100 ng/ml). The 45Ca release stimulated by TNF-alpha and TNF-beta (100 ng/ml), however, was only slightly reduced by indomethacin, flurbiprofen, and meclofenamic acid. The partial inhibitory effect of indomethacin on 45Ca release was seen over a wide range of TNF-alpha concentrations, without affecting the concentration producing half-maximal stimulatory response. TNF-alpha and TNF-beta (100 ng/ml) stimulated bone matrix breakdown, as assessed by analysis of the release of 3H from bone prelabeled with [3H]proline. Also, the stimulatory effect of TNF-alpha and TNF-beta on bone matrix degradation was partially reduced by indomethacin. Hydrocortisone (1 microM) and dexamethasone (0.1 microM) abolished TNF-alpha- and TNF-beta-induced production of PGE2. In contrast to the cyclooxygenase inhibitors, the corticosteroids did not affect the stimulatory action by the cytokines on 45Ca release.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗
PubMed1993

Biocompatibility of polyoxymethylene (Delrin) in bone.

The bone tissue reaction to bulk polyoxymethylene (Delrin) was studied in eight adult albino rabbits followed for up to 5 months after insertion of implants into the tibial metaphyses. Each animal received two implants, one of pure Delrin, the other a 'mosaic' plug with alternating areas of commercially pure titanium and Delrin. At the passage through the cortex, a direct bone-Delrin contact was seen in more than half of the cases, but the contact was usually limited in extent. At the same time, in virtually all sections, a foreign-body reaction with macrophages and giant cells was prominent. It was concluded that bulk Delrin has inferior biocompatibility to titanium, and the advisability of using Delrin as a biomaterial for bone anchorage is questionable.

Animals↗
PubMed1993

Bone-resorbing activity of different periprosthetic tissues in aseptic loosening of total hip arthroplasty.

Using bone organ culture techniques, we studied the production of bone-resorption stimulating factors by the different tissues surrounding loosened total hip arthroplasties. Revision arthroplasties were performed in 13 patients. Various periprosthetic tissues were obtained from these patients. Culture media conditioned by the newly formed capsules contained higher bone-resorption activity when compared to the resorptive activity found in media conditioned by bone-cement membranes. Addition of indomethacin or structurally unrelated non-steroidal anti-inflammatory drugs, or corticosteroids, to bone-cement membrane cultures altered the process of bone resorption in the vicinity of cemented joint implants suggesting that both prostaglandin and other mediators may be involved in the mechanism by which bone-resorbing osteoclasts are stimulated. Our observations indicate that, in the sequence of events that leads to loosening of implants, mediators released from the joint capsules may be more important than those produced by the bone-cement membranes.

Aged↗
PubMed1993

Socket wear assessment. A comparison of three different radiographic methods.

Three different methods to measure wear of total hip sockets from plain radiographs were compared with the results obtained by direct assessment of the internal deformity of 28 retrieved sockets by means of a coordinate measuring machine. The values obtained by the uni-radiographic, the duo-radiographic, and the radiographic methods based on the change of distance between the centers of the socket and the prosthetic head (CEN) all correlated significantly with the standard obtained by the coordinate measuring machine, provided the sockets were not loose. The most accurate radiographic measurements were obtained with the CEN method. A prerequisite for a reliable estimation of socket wear rate is that it be based on observations of radiographically intact sockets.

Hip Joint↗