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Biomedical subjects

A Stenström

Publications and source records attributed to A Stenström.

At least 37 records · Page 2Linked to original sources
PubMed1994

Chevron osteotomy for hallux valgus not improved by additional adductor tenotomy. A prospective, randomized study of 84 patients.

We investigated 106 feet in 84 patients in a prospective randomized series where the clinical and radiographic results of the original chevron osteotomy were compared to the same procedure with the addition of an adductor tenotomy in patients averaging 47 years of age and with a mean follow-up of 3 years. Clinically there was no difference in the satisfaction rate of the two groups, with 58 satisfied and partially satisfied in the 62 operated by chevron osteotomy alone, and 42 of 44 in the group where adductor tenotomy was added. The hallux valgus angle decreased by 7.5 degrees in the group operated with chevron osteotomy and by 9.8 degrees (P 0.04) when an adductor tenotomy was added. The major objective factor affecting satisfaction was the attainment of a decreased ball circumference, shown by the fact that dissatisfied patients had a greater postoperative ball circumference than both satisfied and partially satisfied patients, whereas there were no radiographic correlations to satisfaction. We cannot recommend adding adductor tenotomy to the chevron osteotomy.

Adolescent↗
PubMed1993

Effects of adrenergic and cholinergic stimulation on islet monoamine oxidase activity and insulin secretion in the mouse.

It has been shown that the pancreatic beta-cell monoamines are located in the secretory granules, and that they have an inhibitory influence on insulin secretion. Monoamines are inactivated by the enzyme, monoamine oxidase. We now studied in vivo the relation between adrenergic and cholinergic stimulation, insulin secretion and islet monoamine oxidase activity in the mouse. Monoamine oxidase was assayed with three different substrates, serotonin, dopamine and beta-phenylethylamine. The alpha 2-adrenoceptor agonist, clonidine, induced a moderate inhibition (12-18%) of islet monoamine oxidase activity, accompanied by reduced plasma insulin and elevated plasma glucose levels. The alpha 1-adrenoceptor agonist, phenylephrine, did not induce any changes in these parameters. A marked insulin release following the injection of a maximal dose of the beta 2-adrenoceptor agonist, terbutaline, was accompanied by an increase (30-50%) in islet monoamine oxidase activity. The largest increase in monoamine oxidase activity was observed with serotonin as substrate (50%). These effects on insulin secretion and monoamine oxidase activity could not be blocked by clonidine. Similarly, injection of the non-selective alpha-adrenoceptor agonist, adrenaline, which unlike clonidine does not penetrate the blood-brain barrier, had no effect on insulin release induced by a maximal dose of the nonselective beta-adrenoceptor agonist, isoprenaline. Adrenaline, however, markedly suppressed the insulin release induced by a maximal dose of glucose. Cholinergic muscarinic stimulation by a maximal insulin releasing dose of carbachol did not affect islet monoamine oxidase activity. The results suggest that beta 2-adrenoceptor stimulation of islet monoamine oxidase activity reduced the monoamine content and thereby facilitated the release of insulin.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Agonists↗
PubMed1993

Glucose modulation of islet monoamine oxidase activity in lean and obese hyperglycemic mice.

Islet beta-cell monoamines are known to influence the insulin-releasing mechanisms. These amines are localized in the insulin-secretory granules and are inactivated by the enzyme monoamine oxidase (MAO), a hydrogen peroxide (H2O2)-generating enzyme. The activity of islet MAO may consequently be of importance for insulin secretion. In the present investigation, we studied the relation between islet MAO activity and plasma levels of insulin and glucose in obese (ob/ob) hyperglycemic mice and their lean littermates. In addition, the effect of glucose on the MAO activity of in vitro-cultured islets was studied. MAO activity was assayed with serotonin, dopamine (DA), and beta-phenylethylamine (PEA) as substrates. After an overnight fast in adult (age, 6 months) lean mice, islet MAO activity was increased by 35% to 70%. Plasma levels of glucose and insulin were markedly decreased as expected. However, fasting in adult obese mice either did not affect islet MAO activity (PEA and DA) or induced a slight decrease (serotonin) of approximately 25% (P < .05). Plasma glucose levels in adult obese mice were not significantly affected by the overnight fast. However, a correlation analysis based on individual adult obese mice (fed and fasted) showed a negative correlation between plasma glucose concentration and islet MAO activity with PEA (r = -.65, P < .02) and DA (r = -.66, P < .02), respectively. Further, a positive correlation (r = +.58, P < .05) was found between glucose level and islet MAO activity when using serotonin as substrate. There was no difference in islet MAO activity with PEA and DA as substrates in fed obese versus fed lean mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Influence of beta 2-adrenoceptor stimulation and glucose on islet monoamine oxidase activity and insulin secretory response in the mouse.

Changes in the content of monoamines such as dopamine (DA) and serotonin (5-HT) in the insulin granules are known to influence insulin release. The monoamines are inactivated by monoamine oxidase (MAO), a hydrogen peroxide-generating enzyme, which may be of importance for the redox state of the beta-cell. We studied the action of two different insulin secretagogues, the beta 2-adrenoceptor agonist terbutaline and glucose, on islet MAO activity and the plasma levels of insulin and glucose. MAO was assayed with 5-HT, DA, and beta-phenylethylamine as substrates. At 6 min (but not at 2 or 30 min) after terbutaline injection, marked increases of islet MAO activity and the plasma insulin levels were recorded. The plasma glucose levels were of the same magnitude at all time points. Injection of glucose moderately suppressed enzyme activity at 2 min. This occurred concomitantly with the peak increase in plasma levels of insulin and glucose. At 60 min, when the plasma levels of glucose and insulin were restored to basal, a slight increase in MAO activity was observed. At 2 min after injection of different doses of glucose mixed with a maximal dose of terbutaline, the insulin secretory response was either increased (submaximal glucose dose) or unaffected (maximal dose of glucose) by the beta 2-adrenoceptor stimulator. However, when a maximal dose of glucose was given at 6 min after terbutaline, i.e., when islet MAO activity was increased, the insulin response to glucose was suppressed. Starvation for 24 h induced an increase in islet MAO activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Distal blood pressure as a predictor for the level of amputation in diabetic patients with foot ulcer.

The predictive value of distal blood pressure measurements for the level of amputation was studied prospectively in 161 consecutive diabetic patients with foot ulcers. The patients were treated as outpatients except for periods of surgery and when complications requiring hospital care occurred. All patients were treated pre- and postoperatively by the same multidisciplinary foot care team. Either ankle or toe blood pressure measurement was available in 86% of the patients. Incompressible arteries, ulcer or gangrene at the measuring site, previous amputation, poor general condition, and an emergency situation were factors that excluded standardized ankle and toe blood pressure measurements in 24% and 27% of the patients, respectively. An absolute lower ankle pressure level of 50 mm Hg was found, below which a minor amputation was never sufficient to achieve healing. An ankle pressure below 75 mm Hg was seldom sufficient, and at or above that pressure level, the ankle pressure had no predictive value in this respect. At a toe pressure below 15 mm Hg, a minor amputation was seldom sufficient. Ankle and toe pressure indices gave no further information.

Adult↗
PubMed1992

The influence of metal backing in unicompartmental tibial component fixation. An in vivo roentgen stereophotogrammetric analysis of micromotion.

The fixation of the tibial component in 36 patients with conventionally cemented unicompartmental knee arthroplasties for femorotibial gonarthrosis was studied using roentgen stereophotogrammetric analysis (RSA). Twenty-four tibial components were all-polyethylene while 12 were metal-backed. The follow-up was for 6 years. Significant migration was detected for all cases but two and ranged from 0.3 mm to 5.4 mm. The greater part of the migration occurred during the first 1-2 years, after which two-thirds of the prostheses remained stable. Seven all-polyethylene components were subjected to a stress examination after 1-2 years and displacement, induced by external forces, was found in all seven. A strong correlation was found between the extension of the radiolucent line and the migration. Otherwise, neither demographic, clinical, nor radiographic data correlated with the RSA results. In this study metal backing did not have any influence on prosthetic fixation as measured by RSA.

Aged↗
PubMed1992

Knee arthroscopy using local anesthesia.

This study confirms the feasibility of performing arthroscopy and arthroscopic surgery with patients under local anesthesia. Seventy patients underwent arthroscopy under local anesthesia using mepivacaine with adrenaline. In 49 patients, arthroscopic surgery was performed. It is important to wait at least 20 min after the injection of the anesthetic before surgery to anesthetize the medial part of the joint. There were few complications. Diagnostic and surgical arthroscopy can be successfully performed in the majority of patients with local anesthesia.

Adult↗
PubMed1992

Multicenter study of unicompartmental knee revision. PCA, Marmor, and St Georg compared in 3,777 cases of arthrosis.

The prospective Swedish Knee Arthroplasty Project contained 772 PCA, 1564 Marmor and 1441 St Georg unicompartment prostheses, implanted for gonarthrosis during the period December 1983-July 1990. Follow-up was performed in September 1991. There was a significant difference in the cumulative revision rate after only 2 years, increasing to 15 percent for the PCA, compared with 5-7 percent for the two other types. The difference between PCA and Marmor/St Georg was loosening of the femoral component. Major polyethylene wear was noted in a quarter of the revised PCA tibial components. The wear pattern of Marmor/St Georg was not analyzed in this study.

Actuarial Analysis↗
PubMed1992

Polyethylene wear of the PCA unicompartmental knee. Prospective 5 (4-8) year study of 120 arthrosis knees.

In Lund, 120 arthrosis knees had the PCA unicompartmental endoprosthesis during 1983-1987 and were followed prospectively for 5 (4-8) years. 17 knees were excluded from the final clinical follow-up because of the development of rheumatoid arthritis (2), severe neurologic disease (3), or death (12). Subjectively, 68 knees were much improved, 26 improved and 9 had failed. First-steps problems were only present in the uncemented group of 49 knees. Of the 9 failures (7 cemented and 2 uncemented) 6 were revised. The main reason for revision was loosening of the femoral component (2), tibial component (2), or both components (1), and polyethylene wear (1). However, all revised tibial components showed polyethylene wear, in 4 quite pronounced. Weight-bearing radiographs (61 knees) revealed major polyethylene wear in an additional 14 knees; not only in thin tibial components. There may be an increasing clinical problem due to polyethylene wear. With the presented findings the PCA unicompartmental knee endoprosthesis cannot be recommended.

Aged↗
PubMed1991

Temporal studies of the inhibition of voluntary ethanol intake in the rat induced by intermittent ethanol treatment and some long term neurochemical consequences.

Male rats were injected with ethanol (groups 3 and 5; 2.0 g/kg i.p.) or saline (groups 2 and 4) once a week for 52 weeks. The rats had access to ethanol as a voluntary choice for 24 h either once 6 days after the injection (groups 2 and 3) or twice 3 and 6 days after the injection (groups 4 and 5). At the beginning of the treatment ethanol injections inhibited voluntary ethanol intake if tested 6 days later (groups 3 and 5), but a tolerance developed to this inhibition. During tolerance development the rats in group 5 also drank less ethanol on day 3 than on day 6. No corresponding behaviour was seen in group 4. Thus part of the tolerance was a gradual reduction of the duration of inhibition. During the evaluation period (25 weeks) after the treatment, ethanol exposure (20 weeks) consisted of a continuous choice between ethanol and water. Of different ethanol concentrations both ethanol-injected groups (3 and 5) took the same voluntary dose of ethanol independent of the offered concentration. After 5 weeks without ethanol all rats were killed and a number of neurochemical variables were determined. Compared with almost unexposed rats (group 1) changes were seen in inositol phospholipid breakdown, muscarinic binding sites in hippocampus, noradrenaline concentrations in frontal cortex, hippocampus and hypothalamus, dopamine concentration in frontal cortex and 5-hydroxytryptamine concentration in hypothalamus. In most cases the largest changes were seen in group 5. None of the variables had a constant relation to ethanol intake in the total population. However, significant correlations were found in some of the groups.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1991

Effect of L-dopa administration on islet monoamine oxidase activity and glucose-induced insulin release in the mouse.

Previous studies have shown that the amine precursor L-3,4-dihydroxyphenylalanine (L-DOPA) is rapidly converted to its corresponding amine, dopamine, in islet beta-cells. In the present investigation, we studied the effect of acute L-DOPA administration on islet monoamine oxidase (MAO) activity and on glucose-induced insulin secretory response in mice. It was observed that at 2 min after intravenous L-DOPA administration, there was a marked increase (+35%) in islet MAO activity, with serotonin as substrate. At 7 min, MAO activity towards dopamine was enhanced by 32% and that towards serotonin and phenylethylamine (PEA) was decreased by 23 and 25%, respectively. The inhibitor of L-aromatic amino acid decarboxylase, benserazide, abolished L-DOPA-induced changes of MAO activity, suggesting that the formed dopamine, and not L-DOPA itself, was responsible for the observed effects. At 60 min, no effect by L-DOPA administration on islet MAO activity was noticed. L-DOPA (125 or 250 mumol/kg), given together with glucose, induced a decrease in glucose-induced insulin response. L-DOPA (125 mumol/kg), given 7 min before glucose, totally suppressed glucose-induced insulin response. This inhibition was eliminated through pretreatment with benserazide. Enhancement of glucose-stimulated insulin response, after deposition of horseradish peroxidase (HRP) in beta-cell vacuolar system, was suppressed by L-DOPA. We conclude that acute L-DOPA-induced dopamine accumulation in pancreatic islets is accompanied by rapid changes in MAO activity, concomitant with an inhibitory effect on glucose-stimulated insulin response. Increased hydrogen peroxide production, following increased MAO activity, may possibly augment the inhibitory effect of dopamine accumulation on insulin release.

Animals↗
PubMed1990

Topical treatment of necrotic foot ulcers in diabetic patients: a comparative trial of DuoDerm and MeZinc.

An open randomized controlled study was carried out of 44 diabetic patients with necrotic foot ulcers treated with adhesive zinc oxide tape (MeZinc) or with an adhesive occlusive hydrocolloid dressing (DuoDerm). Fourteen of the 21 patients treated with MeZinc had their necrotic ulcers improved by at least 50% compared to six out of 21 with the hydrocolloid dressing (P less than 0.025). Fifteen patients showed an increase in the area of necrosis during the course of the 5-week study and of these, 10 had been treated with the hydrocolloid dressing.

Administration, Topical↗
PubMed1990

The treatment of tarsometatarsal injuries.

In order to analyze the value of operative treatment for tarsometatarsal injuries, 31 consecutive fracture-dislocation injuries from 1975 to 1988, and 11 cases of undislocated injuries were reviewed. Forty patients (41 injuries) could be contacted. The average follow up was 5 years. Twenty-two of the dislocated injuries were treated with open reduction and fixation, usually K-wires. All injuries were classified radiologically. By means of a questionnaire, it was found that 7 had excellent results, 13 good, and 21 poor. No case where anatomical reduction was not achieved could be classified as excellent, and half (5 of 10) received full disability pension. When anatomical reduction was achieved, half had good or excellent results and only 5 of 20 received a disability pension. Initially undislocated injuries had a better prognosis, with 8 of 11 having excellent or good results, and none receiving pension. These injuries should be treated aggressively with open reduction and fixation when there is any displacement. Despite this treatment, one-half of patients with dislocated injuries as well as one-fourth of those with initially undislocated injuries will still suffer from pain and permanent disability probably due to soft tissue damage and instability.

Adolescent↗
PubMed1990

Cold flow reduced by metal backing. An in vivo roentgen stereophotogrammetric analysis of unicompartmental tibial components.

Thirty-six cases of unicompartmental arthroplasty for gonarthrosis were followed for 6 years. The arthroplasties were prepared for roentgen stereophotogrammetric analysis (RSA) by marking the tibial components and the tibial methaphysis with tantalum balls. Nineteen out of 24 cases with a polyethylene tibial component had an increase in intermarker distances signifying progressive enlargement of the prosthesis due to cold flow. The enlargement was up to 2.8 percent of the circumference and was greater for 9 mm than for 12 mm thick components. Twelve cases with a metal-backed tibial component showed no cold flow. No correlation between cold flow and demographic, clinical, or radiographic data was found.

Aged↗
PubMed1990

Porous coated anatomic tricompartmental tibial components. The relationship between prosthetic position and micromotion.

Micromotion of the tibial component, both as migration over time and as inducible displacement in response to external physiologic forces, was studied in 20 cases of gonarthrosis. The patients had Porous Coated Anatomic primary total knee arthroplasty and were followed for four years. All cases but one were clinically successful. Thirteen components were inserted without cement, while in seven, high-viscosity Palacos cement was used. Full postoperative weight bearing was allowed in all cases. During the first year, noncemented components migrated a mean of 2.6 mm, while cemented components migrated a mean of 1.1 mm. About 1 mm of migration of noncemented components was in the downward direction, i.e., subsidence occurred, mostly during the first year. After one year, the noncemented components had stabilized more than the cemented ones. There was a significant correlation between the migration after one year and the postoperative prosthetic position and alignment of the leg. A mean maximum inducible displacement (the total vector displacement of the prosthetic marker that moved the most) of 0.7 mm and 0.4 mm was found for noncemented and cemented components, respectively. The micromotion found was of the same magnitude as that for other cemented and noncemented prosthetic systems previously reported.

Aged↗
PubMed1990

A long-term follow-up study of total meniscectomy in children.

The long-term effects of single meniscectomy in 89 children have been analyzed at an average of 16.8 years after surgery. Seventy-four percent were pleased with the outcome, but only 52% or 58% had objectively satisfactory results according to the two scoring systems used. Significantly poorer results were achieved with lateral meniscectomies. The range of movement was significantly decreased after lateral meniscectomy. Minor instabilities were recorded in 45% of the patients and major instabilities in 15%. Anteroposterior and rotatory instabilities were objectively measured, and a significant increase was noted in knees that had lateral meniscectomy. Grade I gonarthrosis was recorded in 39% of the surgically treated knees and Grades II and III gonarthroses in 9%. The joint space was significantly reduced in all knees irrespective of the injured compartment.

Adolescent↗
PubMed1989

Wound classification is more important than site of ulceration in the outcome of diabetic foot ulcers.

The importance of wound classification and site of ulceration was evaluated in 314 consecutive diabetic patients with foot ulcers. The ulcers were classified as superficial (through the full thickness of the dermis; n = 150), deep (n = 50), osteomyelitis and/or abscess (n = 46), minor gangrene (n = 39) or major gangrene (n = 29). Wound healing was defined as intact skin for at least 6 months. In patients with superficial and deep ulcers, primary healing occurred in 88% and 78%, respectively, compared with 57% in those patient who developed an abscess and/or osteomyelitis. Only 2 out of 68 patients with gangrene healed (through mummification) without amputation. Patients with gangrene had lower ankle and toe blood pressure than patients with all other types of ulcers. There were only marginal differences in primary healing rate between different ulcer sites. The highest rate was seen in ulcers localized to the metatarsal heads (78%). Patients with multiple ulcers had the lowest primary healing rate (5%) compared with single ulcers at all sites. These differences were probably due to circulatory factors, since patients with multiple ulcers had lower distal perfusion pressures compared with all other groups.

Blood Pressure↗