Biomedical subjects

A Ekelund

Publications and source records attributed to A Ekelund.

At least 19 recordsLinked to original sources

PubMed2005

Biochemical markers of bone turnover in the dairy cow during lactation and the dry period.

We measured a bone-formation marker recognizing osteocalcin, and a bone-resorption marker recognizing C-telopeptide (CT(x)) fragments of collagen type I, in a longitudinal study. The levels of these markers in the plasma of dairy cows (n=11) were recorded over a 12 month postpartum period, including a full lactation and a dry period. The plasma concentration of CT(x) was highest in the first week after parturition. It then declined slowly over the next 33 weeks and remained low until the next parturition. Osteocalcin concentration was lowest around parturition, reached a plateau during mid-lactation, then fell again towards term. There were large variations in bone metabolism during a lactation, that were not directly related to milk production. These results may be used to facilitate appropriate adjustments to calcium and phosphorous concentrations in the diet, reflecting the specific needs of each stage of the reproductive cycle.

Animals↗

PubMed2002

Effects of iso- and hypervolemic hemodilution on regional cerebral blood flow and oxygen delivery for patients with vasospasm after aneurysmal subarachnoid hemorrhage.

BACKGROUND: Arterial vasospasm after subarachnoid hemorrhage may cause cerebral ischemia. Treatment with hemodilution, reducing blood viscosity, and hypervolemia, increasing cardiac performance and distending the vasospastic artery, are clinically established methods to improve blood flow through the vasospastic arterial bed. METHOD: Eight patients with transcranial Doppler verified vasospasm after subarachnoid hemorrhage were investigated with global (two-dimensional (133)Xenon) and regional (three-dimensional (99 m)Tc-HMPAO) cerebral blood flow (CBF) measurements, before and after 1/iso- and 2/hypervolemic hemodilution. Hematocrit was reduced to 0.28 from 0.36. Hypervolemia was achieved by increasing blood volume by 1100 ml. FINDINGS: Isovolemic hemodilution increased global cerebral blood flow from 52.25+/-10.12 to 58.56+/-11.73 ml * 100 g(-1) * min(-1) (p<0.05), but after hypervolemic hemodilution CBF returned to 51.38+/-11.34 ml * 100 g(-1) * min(-1). Global cerebral delivery rate of oxygen (CDRO(2)) decreased from 7.94+/-1.92 to 6.98+/-1.66 ml * 100 g(-1) * min(-1) (p<0.001) during isovolemic hemodilution and remained reduced, 6.77+/-1.60 ml * 100 g(-1) * min(-1) (p<0.001), after the hypervolemic hemodilution. As a test of the hemodilution effect on regional CDRO(2) an ischemic threshold was defined as the maximal amount of oxygen transported by a CBF of 10 ml * 100 g(-1) * min(-1) at a Hb 140 g/l which corresponds to a CDRO(2) of 1.83 ml * 100 g(-1) * min(-1). The brain volume with a CDRO(2) exceeding the ichemic threshold was 1300+/-236 ml before intervention. After isovolemic hemodilution the non-ischemic brain volume was reduced to 1206+/-341 (p<0,003). After hypervolemic hemodilution the non-ischemic brain volume remained reduced at 1228+/-347 ml (p<0.05). INTERPRETATION: The present study of controlled isovolemic hemodilution demonstrated increased global CBF, but there was a pronounced reduction in oxygen delivery capacity. Both CBF and CDRO(2) remained decreased during further hypervolemic hemodilution. We conclude that hemodilution to hematocrit 0.28 is not beneficial for patients with cerebral vasospasm after SAH.

Adult↗

PubMed1999

Arthroscopic lavage reduced the recurrence rate following primary anterior shoulder dislocation. A randomised multicentre study with 1-year follow-up.

Young individuals have a high recurrence rate following non-operative treatment of traumatic primary anterior shoulder dislocation. The present multicentre study was undertaken to find out whether the results could be improved by using arthroscopic lavage as treatment. Sixty patients aged 16-30 years, with traumatic primary anterior shoulder dislocation were randomised into two groups. One group was treated with arthroscopic lavage within 10 days, while the other group was treated non-operatively. Rehabilitation was otherwise identical. At 1-year follow-up, 4 of 30 patients (13%) in the lavage group had had redislocation compared with 13 of 30 (43%) in the group treated non-operatively (P = 0.01). The difference in recurrence rate was more pronounced in younger patients. The functional outcome according to the Rowe shoulder score was better in the lavage group (P = 0.003), as was the anterior stability according to the apprehension test (P = 0.008). We conclude that arthroscopic lavage reduced the recurrence rate and produced a better functional outcome at 1-year follow-up than the non-operative treatment in young individuals.

Absenteeism↗

PubMed1999

Additional colloids have only a minor haemodilutive effect after surgery for aneurysmal subarachnoid haemorrhage.

Haemodilution is commonly used as prophylaxis, as well as treatment for cerebral ischaemia after aneurysmal subarachnoid haemorrhage (SAH). Thirty-six patients operated for aneurysmal SAH were evaluated retrospectively; 24 received haemodilutive therapy and 12 patients, as a control group, received no additional therapy. There was a 'spontaneous' drop in haematocrit by 22% in both groups, and a corresponding drop in haemoglobin by 23% in the treatment group and 19% in the non-haemodiluted group, during the first 4 days after the SAH. After the initial decrease the haematocrit remained stable between 0.28 and 0.33 until day 14 in both groups. The haemodilutive group had only a minor lower haematocrit level during days 8-12 as the additional fluid resulted in increased renal excretion. This minor difference was, however, significant (p < 0.02).

Adult↗

PubMed1999

No effect of immunosuppression with cyclosporin A detected on bone ingrowth into cancellous allo- and xenografts in the rat.

We studied the effects of the immunosuppressant cyclosporin A on bone ingrowth into allo- and xenografts in the rat using titanium bone chambers. The bone chambers were implanted bilaterally in the tibia. Each rat had one allograft and one xenograft. At 6 weeks the distance of soft tissue and bone ingrowth was measured on histological slides. In xenografts, soft-tissue ingrowth was only slightly less than in allografts, but the ingrown tissue became much less ossified. These differences were unaffected by cyclosporin A treatment, suggesting that the lesser amount of bone formation in xenografts is only weakly associated with T-cell-dependent immune reactions.

Animals↗

PubMed1998

[New knowledge of the mysterious "frozen shoulder". Surgical treatment can accelerate the recovery in more serious cases].

Frozen shoulder (adhesive capsulitis) affects 2-5 per cent of the population, but is most common in the 40-60-year-old age group. The disorder is divided into three phases, the painful, the stiff and the recovery phases. In most cases the condition is self-limiting with negligible residual manifestations, though its average duration is about 30 months. New findings suggest frozen shoulder to be a Dupuytren-like disorder. Pain relief and physiotherapy are usually sufficient, but in more severe cases manipulation with the patient under anaesthesia, possibly combined with distension arthrography or arthroscopic release, may yield rapid improvement in shoulder function.

Adult↗

PubMed1998

Transcranial cerebral oximetry related to transcranial Doppler after aneurysmal subarachnoid haemorrhage.

Noninvasive methods for detecting cerebral artery vasospasm, still a serious complication following aneurysmal subarachnoid haemorrhage, are of vital interest. Up-to-date transcranial Doppler ultrasound (TCD) has proved to be sensitive in detecting vasospasm in the middle cerebral artery, but has less accuracy for other cerebral arteries. Transcranial cerebral oximetry (TCCO) is a new non-invasive technique which may increase the reliability for detecting cerebral ischaemia. The purpose of the present study was to evaluate a putative correlation between TCCO and TCD. We examined the two hemispheres in 14 patients with the aim of evaluating a proposed correlation between TCD and TCCO. Analysis of all absolute values (maximum TCD mFV and minimum TCCO saturation, respectively) in all series indicate a correlation between TCCO and TCD, p < 0.01, r = -0.62. All patients with TCD mean flow velocity > 120 cm/s also presented TCCO saturation < 60%. Conversely, all patients with normal TCCO saturation (> or = 63%) presented normal or moderately increased TCD velocities. In clinical neurosurgical practice it is of great interest if a true correlation between TCD and TCCO exists. The present results support the assumption that TCCO may enhance the reliability for detecting cerebral ischaemia after aneurysmal subarachnoid haemorrhage.

Aneurysm, Ruptured↗

PubMed1998

Arthroscopic shoulder stabilization using transglenoid sutures.

The results of arthroscopic stabilization using multiple transglenoid sutures in 24 patients with posttraumatic recurrent anterior shoulder instability are presented with a minimum follow-up of 2 years. No serious complications were recorded. There were 2 recurrences. The remaining 22 patients had good or excellent results according to the modified Rowe score, with a median score of 89. The median value for loss of external rotation was 5 degrees. Seventeen patients were active in sports and 11 returned to the same sports at the same competitive level.

Adolescent↗

PubMed1997

Acute hemiarthroplasty after proximal humerus fracture in old patients. A retrospective evaluation of 18 patients followed for 2-7 years.

We evaluated the outcome of acute shoulder hemiarthroplasty in 18 patients following displaced three- and four-part fractures of the proximal humerus. The mean age of the patients was 82 (70-92) years and the average follow-up time was 3.5 (2-7) years. No revision due to loosening was performed. All patients were evaluated concerning activities of daily living, degree of pain (VAS-scale, 0-100 mm) and range of motion. The patients had a low functional level, but were able to sleep on the operated side and keep up their hobby. 11 patients were painfree and the worst pain recorded was 28 mm. Range of motion for all movements, except extension, was statistically significant lower than for the non-operated side. We conclude that in elderly patients acute hemiarthroplasty following three- or four-part fractures of the proximal humerus results in good pain relief, but a more limited range of motion than that reported for younger patients.

Activities of Daily Living↗

PubMed1997

Neuropeptides in heterotopic bone induced by bone matrix in immunosuppressed rats.

The effects of cyclosporin A on the occurrence of neuroendocrine peptides in bone induced by demineralized allogeneic and xenogeneic bone matrix were studied in rats. Cyclosporin A enhanced bone induction in demineralized allogeneic bone matrix implants by 40% to 50% at 4 weeks, whereas there was no difference to the control group at 8 weeks. In demineralized xenogeneic bone matrix implants there was virtually no cartilage or bone formation at 4 weeks, but some bone and cartilage formation was seen at 8 weeks. In both cyclosporin A treated groups the net bone formation in demineralized xenogeneic bone matrix implants was increased four to five times at 4 weeks. Cyclosporin A treatment did not alter the temporal occurrence or distribution of neuropeptide containing nerve fibers in the bone induced by allogeneic bone matrix. Fibers containing substance P, calcitonin gene related peptide, neuropeptide Y, vasoactive intestinal peptide, and tyrosine hydroxylase were detected in the ossicles of cyclosporin A treated and control rats. In the xenogeneic bone matrix of the control group, no immunoreactive nerve fibers could be detected at 4 weeks, but at 8 weeks all five neuropeptides were detected. However, after cyclosporin A treatment immunoreactive nerve fibers could be seen at 4 weeks in the demineralized xenogeneic bone matrix implants. Thus, immunologic properties of the inductive matrix affect the yield of mineralized bone and the degree of innervation. Cyclosporin A decreases the immune response and enhances the formation of bone and the number of transmitter identified nerves in demineralized xenogeneic bone matrix induced ossicles.

Animals↗

PubMed1996

Is transcranial Doppler sonography useful in detecting late cerebral ischaemia after aneurysmal subarachnoid haemorrhage?

Transcranial Doppler (TCD) examination was performed in 109 patients with aneurysmal subarachnoid haemorrhage. Fifty-seven demonstrated flow velocities exceeding 120 cm/s in the middle cerebral artery. Of these, 23 developed delayed ischaemic deficit (DID). Mean flow velocity in this group was 170, SD 12.8 cm/s, in comparison with 155, SD 11.2 cm/s in the 34 patients without late signs of cerebral ischaemia. This difference is significant (p = 0.0269). In the 34 patients without DID, but TCD > 120 cm/s, 17 received anti-ischaemic therapy based on TCD values only, while 17 were given no additional treatment. The mean TCD values and the neurological outcome in the two groups were similar. A rapid increase in flow velocities of 50 cm/s or more during a 24-h period seemed to be a strong predictor of symptomatic vasospasm as seven out of 12 patients developed DID, five with permanent neurological sequelae. The study confirms results from other centres, that a strict correlation between high TCD flow velocities and occurrence of DID does not exist.

Adult↗

PubMed1995

Transcranial Doppler ultrasound in hypertensive versus normotensive patients after aneurysmal subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Arterial hypertension is a negative prognostic risk factor after aneurysmal subarachnoid hemorrhage (SAH). Transcranial Doppler ultrasound is commonly used for measuring blood flow velocities to predict cerebral ischemia due to vasospasm after SAH. Our purpose was to evaluate the influence of arterial hypertension on blood flow velocities in the cerebral circulation after aneurysmal SAH. METHODS: With transcranial Doppler ultrasound we compared the blood flow velocities in matched groups of hypertensive and normotensive patients with aneurysmal SAH. Twenty-four patients with arterial hypertension were examined daily during a 2-week period. As controls, 24 normotensive patients, also with SAH, were matched by age, sex, neurological status, and clinical outcome. RESULTS: Minimum, mean, and maximum flow velocities in the middle cerebral artery in the hypertensive patients were significantly lower than in the normotensive individuals, with P = .02 for minimum, P = .02 for mean, and P = .02 for maximum. There was no statistical significance for pulsatility index differences in these groups (P = .45). Diastolic notch was noted in two of the hypertensive and in six of the normotensive patients. CONCLUSIONS: The results indicate that even moderately increased flow velocities in hypertensive patients may represent significant vasospasm.

Adult↗

PubMed1993

Trochanteric osteotomy for recurrent dislocation of total hip arthroplasty.

Twenty-one patients with recurrent dislocation of total hip arthroplasty were treated by trochanteric osteotomy and distal advancement of the greater trochanter. There were no malpositioned prostheses. In 17 patients no further dislocations occurred. One patient, who had the hip arthroplasty in a paretic leg, continued to dislocate after the osteotomy and the prosthetic components were removed 5 months after surgery. The remaining three patients became stable after further surgery: cup augmentation in one and reattachment of the greater trochanter in two. Advancement of the greater trochanter is recommended in patients with recurrent dislocation of their total hip arthroplasty when no apparent malposition of the prosthetic components can be identified.

Aged↗

PubMed1992

Effects of cyclosporin A on experimental new bone formation in rats.

The effects of the immunosuppressive drug cyclosporin A (CsA) on bone induction by demineralized allogeneic (rat) bone matrix (DABM) and demineralized xenogeneic (rabbit) bone matrix (DXBM) were studied. Growing rats were implanted with three samples each of DABM and DXBM. Groups of eight rats were treated with 0.5 or 2 mg CsA/kg body weight for four weeks and compared with a placebo group. Cyclosporin A treatment enhanced bone induction in DABM implants by 40 to 50% at four weeks, whereas there was no difference from the control group at eight weeks. Demineralized xenogeneic bone matrix induced virtually no bone in control rats at four weeks, whereas the net bone formation increased four to five times in both groups of CsA-treated rats. At eight weeks, DXBM without CsA had induced some bone formation, and the amount was almost equal to that of DABM implants in CsA-treated groups. Also, the mineral accretion rates of DXBM were equal to DABM implants in CsA-treated rats. Cyclosporin A treatment doubled the uptake of 45Ca in the orthotopic skeleton (femora) at four weeks without affecting the mineral content, indicating an increased mineral turnover. Immunologic reactions may inhibit bone induction by DXBM, which can be counteracted by treatment with CsA.

Animals↗

PubMed1992

Total hip arthroplasty in patients 80 years of age and older.

One hundred fifty-seven consecutive patients (162 total hip arthroplasties) 80 years of age and older were observed for one year after total hip arthroplasty (THA). Clinical results and complications were recorded. The indication for surgery was degenerative joint disease (DJD) in one half of the patients and complications to proximal femoral fractures in the other half. The mean age was 83 years old in both groups. In 80% of the patients, no complications were recorded during the first year. Three patients died during the first three months. Two deep infections occurred (1.2%). The dislocation rate was 9.2% (15/162). There was a lower dislocation rate (4/84) in the DJD group compared to the fracture group (11/78). All nine recurrent dislocations occurred in the fracture group and were treated with either trochanteric osteotomy (five) or removal of the prosthesis (four). In the patients operated on with trochanteric osteotomy, no further dislocations occurred. The mean hospital stay was 13 days. After one year, 88% (112/127) of the patients who could be observed had good or excellent results. Total hip arthroplasty in the elderly is a reasonably safe method and yields good functional results. Dislocations, however, were common in patients operated on for complications from proximal femoral fractures, and the risk for recurrent dislocation was high (9/11). In these patients, trochanteric osteotomy is recommended.

Aged↗

PubMed1991

Tissue adhesives inhibit experimental new bone formation.

The effect of the cyanoacrylate tissue adhesive Histoacryl on new bone formation was studied in rats. Experimental heterotopic new bone formation was induced by implanting pieces of demineralized allogeneic bone matrix (DABM) in the abdominal wall of 10 growing Sprague-Dawley rats. This produces cartilage formation within and around the implants after 10 days, followed by enchondral ossification and the formation of an ossicle with remodelling bone and bone marrow after three weeks. Prior to implantation, the DABM-implants were treated with increasing amounts of the tissue adhesive n-Butyl-2-cyanoacrylate-monomer (Histoacryl). New bone formation was quantified at three weeks by assay of the ash content of the implants as a measure of net bone formation, by 45calcium uptake prior to sacrifice, and by histology. Treatment of DABM with the cyanoacrylate caused an intense inflammatory process with a foreign body reaction, and abolished bone induction and new bone formation. Tissue adhesives should be used with caution in fracture surgery since they inhibit new bone formation, cause a foreign body reaction, and may impede fracture healing.

Animals↗

PubMed1991

Experimental induction of heterotopic bone.

Heterotopic bone can be induced in experimental animals by trauma to the soft tissues, by induction from living cells, or by extracts from bone and teeth. In the first two types, the mechanism of the inductive process is not known, whereas in the latter, a factor isolated from bone matrix induces bone formation. Mesenchymal cells in bone marrow are determined for development into cartilage and bone cells and only an unspecific stimulus, such as trauma or autotransplantation, is sufficient for the development into mature osteogenic tissue. Mesenchymal cells will not differentiate into bone cells unless stimulated by a specific inductive substance, bone morphogenetic protein (BMP). Implanted to a heterotopic site, BMP induces undifferentiated mesenchymal cells into a bone morphogenetic pathway of development, causing heterotopic bone formation. The quantitative inductive response is dependent on the source of the BMP, and the bone formation is also determined by the recruitment of inducible target cells and by the environment at the implantation site. Hence, the environment at the implantation site is of major importance for the amount of bone formed. BMP initiates a cascade of events that is modulated by endocrine and paracrine factors. The heterotopic bone has all the morphologic and biochemical characteristics of orthotopic bone, is subjected to turnover, and even has the intriguing ability to generate the formation of bone marrow. Experimental induction of heterotopic bone has become a most useful method to study osteoneogenesis and has supplied important information on the prerequisites for new bone formation and on the regulation of bone metabolism.

Animals↗

PubMed1990

Heterotopic new bone formation causes resorption of the inductive bone matrix.

The bone matrix of growing rats was labeled by multiple injections of 3H-proline, and demineralized bone matrix (DBM) was prepared. The DBM was allotransplanted heterotopically into growing rats. New bone formation was induced in and around the implants. The new bone formation was accompanied by a decrease in the content of 3H; 20 and 30 days after implantation, 72% and 46%, respectively, of the activity remained in the implants. Daily injections of indomethacin (2 mg/kg) inhibited calcium uptake by about 20% at 20 and 30 days and inhibited the release of 3H from the DBM to a similar degree. Heterotopic bone induction by DBM is accompanied by matrix resorption, and inhibition of the new bone formation decreases the resorption of DBM.

Animals↗