Biomedical subjects

J Karlsson

Publications and source records attributed to J Karlsson.

At least 55 records · Page 3Linked to original sources

PubMed2001

Eccentric overload training for patients with chronic Achilles tendon pain--a randomised controlled study with reliability testing of the evaluation methods.

The purpose was to examine the reliability of measurement techniques and evaluate the effect of a treatment protocol including eccentric overload for patients with chronic pain from the Achilles tendon. Thirty-two patients with proximal achillodynia (44 involved Achilles tendons) participated in tests for reliability measures. No significant differences and strong (r=0.56-0.72) or very strong (r=0.90-0.93) correlations were found between pre-tests, except for the documentation of pain at rest (P<0.008, r=0.45). To evaluate the effect of a 12-week treatment protocol for patients with chronic proximal achillodynia (pain longer than three months) 40 patients (57 involved Achilles tendons) with a mean age of 45 years (range 19-77) were randomised into an experiment group (n=22) and a control group (n=18). Evaluations were performed after six weeks of treatment and after three and six months. The evaluations (including the pre-tests), performed by a physical therapist unaware of the group the patients belonged to, consisted of a questionnaire, a range of motion test, a jumping test, a toe-raise test, a pain on palpation test and pain evaluation during jumping, toe-raises and at rest. A follow-up was also performed after one year. There were no significant differences between groups at any of the evaluations, except that the experiment group jumped significantly lower than the control group at the six-week evaluation. There was, however, an overall better result for the experiment group with significant improvements in plantar flexion, and reduction in pain on palpation, number of patients having pain during walking, having periods when asymptomatic and having swollen Achilles tendon. The controls did not show such changes. Furthermore, at the one-year follow-up there were significantly more patients in the experiment group, compared with the control group, that were satisfied with their present physical activity level, considered themselves fully recovered, and had no pain during or after physical activity. The measurement techniques and the treatment protocol with eccentric overload used in the present study can be recommended for patients with chronic pain from the Achilles tendon.

Achilles Tendon↗

PubMed2001

Functional outcome of anterior cruciate ligament reconstruction in recreational and competitive athletes.

The aim of this study was to compare the outcome after anterior cruciate ligament reconstruction in recreational and competitive athletes, with a minimum follow-up of two years. Forty-nine patients (24 males and 25 females) who, at the time of the index injury, were classified as recreational athletes (Tegner level 2-5) were compared with 226 patients (61 females and 165 males) who, at the time of the index injury, were classified as competitive athletes (Tegner level 9-10). At the follow-up, no significant differences were found between the study groups in terms of the Lysholm score, IKDC evaluation system, one-leg-hop test, KT-1000 laxity measurements, anterior knee pain and the patients' subjective evaluation of the results. However, the competitive athletes displayed a significantly higher reduction in Tegner activity level than the recreational athletes. The functional and objective results after anterior cruciate ligament reconstruction were comparable for the recreational and competitive athletes. We, therefore, conclude that anterior cruciate ligament reconstruction could be recommended for recreational athletes as well as competitive athletes.

Adolescent↗

PubMed2001

Homologous expression and characterization of Cel61A (EG IV) of Trichoderma reesei.

There are currently four proteins in family 61 of the glycoside hydrolases, from Trichoderma reesei, Agaricus bisporus, Cryptococcus neoformans and Neurospora crassa. The enzymatic activity of these proteins has not been studied thoroughly. We report here the homologous expression and purification of T. reesei Cel61A [previously named endoglucanase (EG) IV]. The enzyme was expressed in high amounts with a histidine tag on the C-terminus and purified by metal affinity chromatography. This is the first time that a histidine tag has been used as a purification aid in the T. reesei expression system. The enzyme activity was studied on a series of carbohydrate polymers. The only activity exhibited by Cel61A was an endoglucanase activity observed on substrates containing beta-1,4 glycosidic bonds, e.g. carboxymethylcellulose (CMC), hydroxyethylcellulose (HEC) and beta-glucan. The endoglucanase activity on CMC and beta-glucan was determined by viscosity analysis, by measuring the production of reducing ends and by following the degradation of the polymer on a size exclusion chromatography system. The formation of soluble sugars by Cel61A from microcrystalline cellulose (Avicel; Merck), phosphoric acid swollen cellulose (PASC), and CMC were analysed on a HPLC system. Cel61A produced small amounts of oligosaccharides from these substrates. Furthermore, Cel61A showed activity against cellotetraose and cellopentaose. The activity of Cel61A was several orders of magnitude lower compared to Cel7B (previously EG I) of T. reesei on all substrates. One significant difference between Cel61A and Cel7B was that cellotriose was a poor substrate for Cel61A but was readily hydrolysed by Cel7B. The enzyme activity for Cel61A was further studied on a large number of carbohydrate substrates but the enzyme showed no activity towards any of these substrates.

Base Sequence↗

PubMed2001

Plantar flexor muscle function in open and closed chain.

In the present study, the torque or work produced during isometric, pure concentric and eccentric-concentric plantar flexions, performed in sitting, standing and prone were measured. The electromyographic (EMG) activity was measured from the soleus, gastrocnemius medialis, tibialis anterior and rectus femoris muscles. The isometric tests showed the highest torques in the standing test. The rectus femoris and gastrocnemius activities were lower in the prone than in the standing test. The sitting test showed lower activities in all muscles of the lower leg compared with the standing test. No differences in work between the prone and sitting tests were found during the concentric phases. Higher rectus femoris activity in the eccentric-concentric test and lower activity in the triceps surae during the concentric phases were seen in the sitting compared with the prone test. We conclude that tests of overall functional ability should be performed in the standing position while specific tests of the plantar flexors should be performed in the prone position.

Adult↗

PubMed2001

Treatment efficacy of intermittent claudication by invasive therapy, supervised physical exercise training compared to no treatment in unselected randomised patients II: one-year results of health-related quality of life.

OBJECTIVE: to compare the effectiveness of invasive therapy, supervised physical training and no treatment in terms of health-related quality of life (HRQL) in patients with intermittent claudication (IC). DESIGN: a prospective, randomised, controlled study. MATERIALS: a total of 253 unselected patients with stable IC were sequentially randomised into 3 balanced treatment groups. At 1 year follow-up data from a battery of generic and disease specific HRQL questionnaires, and global indices of quality of life and physical condition were available in 171 patients. RESULTS: compared with a non-diseased reference group, claudicants were substantially limited in daily physical functioning, but little affected regarding emotional, cognitive and social functioning, or well-being. Invasive therapy yielded significantly greater improvements in some aspects of physical functioning and walk-related symptoms than training. Training was not superior to invasive therapy on any HRQL dimension and superior to no treatment on only one dimension. Treatment effects, however, were generally small-to-moderate and levels of physical dysfunction in all groups remained higher than reference values. CONCLUSIONS: invasive therapy is more effective than supervised training in alleviating illness-specific symptoms and improving certain aspects of physical functioning - the primary HRQL domains impacted on by IC and the principal goals of its treatment. However, since treatment effect sizes were at most moderate and given that untreated claudicants reported at most small deterioration in HRQL, the level of evidence supporting invasive therapy is modest.

Activities of Daily Living↗

PubMed2001

Treatment efficacy of intermittent claudication by surgical intervention, supervised physical exercise training compared to no treatment in unselected randomised patients I: one year results of functional and physiological improvements.

OBJECTIVES: to compare the effect of surgery, exercise and simple observation on maximum exercise power in claudicants. DESIGN: prospective, randomised study. METHODS: a total of 264 unselected claudicants were randomised to supervised exercise training, invasive treatment (open surgical or endovascular procedures) or observation. One year treatment outcomes were analysed on an intention to-treat basis. RESULTS: invasively treated patients showed a significant improvement in maximum walking power, stopping distance, post-ischaemic blood flow and big toe pressure at one year. Patients randomised to physical exercise training or to the control group did not improve in any outcome measure. CONCLUSION: invasive treatment increased walking capacity, leg blood pressure and flow. Supervised physical exercise training offered no therapeutic advantage compared to untreated controls.

Adult↗

PubMed2001

Kinematics after tear in the anterior cruciate ligament: dynamic bilateral radiostereometric studies in 11 patients.

We studied the kinematics of both knees using radiostereometry in 11 patients with unilateral injury of the anterior cruciate ligament and normal contralateral knee. Continuous radiostereometric exposures at a speed of 24 exposures a second were performed, when the patients ascended an 8 cm high platform. The tibial center was more dorsally displaced and the tibia more externally rotated on the injured side. This increasing external tibial rotation was associated with increased anterior displacement of the lateral femoral condyle. The latter also displayed less anterior-posterior translations during continuous extension. The anterior-posterior translation of the medial condyle was about the same as on the uninjured side. Changes in the kinematics of the knee joint due to rupture of the anterior cruciate ligament can result in an abnormal joint load, which may increase the risk of damage to the cartilage and the menisci.

Adolescent↗

PubMed2001

Angiotensin converting enzyme gene polymorphism predicts blood pressure response to angiotensin II receptor type 1 antagonist treatment in hypertensive patients.

OBJECTIVES: To determine whether polymorphisms in the renin-angiotensin system can predict blood pressure-lowering response to antihypertensive treatment; more specifically, in response to treatment with irbesartan or atenolol. DESIGN AND METHODS: Eighty-six patients with hypertension were randomized to double-blind treatment with either the angiotensin II type 1 receptor antagonist irbesartan or the beta1 adrenergic receptor blocker atenolol and followed for 3 months. We analysed angiotensinogen T174M and M235T, angiotensin converting enzyme (ACE) I/D and angiotensin II type 1 receptor A1166C polymorphisms and related them to blood pressure reduction. RESULTS: The mean reductions in blood pressure were similar for both treatments. In the irbesartan group, individuals homozygous for the ACE gene I allele showed a greater reduction in diastolic blood pressure, exceeding those with the D allele (-18 +/- 11 SD versus -7 +/- 10 mmHg, P = 0.0096). This was not the case during treatment with atenolol, and the interaction term between type of treatment and ACE II genotype was significant (P = 0.0176). The angiotensinogen and angiotensin II type 1 receptor polymorhisms were not related to the response to treatment. CONCLUSIONS: ACE genotyping predicted the blood pressure-lowering response to antihypertensive treatment with irbesartan but not atenolol. Thus, specific genotypes might predict the response to specific antihypertensive treatment.

Adrenergic beta-Antagonists↗

PubMed2001

Long-term outcome of anatomical reconstruction versus tenodesis for the treatment of chronic anterolateral instability of the ankle joint: a multicenter study.

The long-term clinical outcome after anatomical reconstruction and tenodesis in the treatment of chronic anterolateral ankle instability was assessed in a retrospective multicentre study. The first group (AR) consisted of 25 patients (mean age at operation 22 yrs +/- 5.7) who underwent anatomical reconstruction and the second group (TE) of 29 patients (mean age 23 yrs +/- 6.6) who underwent tenodesis. For both groups, the mean follow-up period was 12.3 yrs (AR +/- 2.5 yrs, TE +/- 2.7 yrs). At physical examination, there were significantly more patients in the TE group (n=18) with a positive anterior drawer sign as compared with the AR group (n=7) (p=0.02). Medially located degenerative changes in the ankle joint as seen on standard radiographs were seen more often in the TE group (n=7) than in the AR group (n=1) (p=0.03). The mean talar tilt, 4.7 degrees in the AR group vs 6.9 degrees in the TE group, (p=0.02) and anterior talar translation, 2.9 mm in the AR group vs 4.3 mm in the TE group, (p=0.04) were significantly higher in the TE group at radiographic stress examination. According to the rating system developed by Good et al. (1975), significantly fewer patients in the TE group (n=8) had an excellent result as compared with the AR group (n=15) (p=0.03) and more patients in the TE group (n=9) had a fair or poor result (p=0.04) as compared with the AR group (n=2). We conclude that a tenodesis procedure does not restore the normal anatomy of the lateral ankle ligaments. When compared with anatomical reconstruction, a tenodesis leads to inferior results in terms of functional and mechanical stability, as well as overall satisfaction at long-term follow-up.

Adult↗

PubMed2001

Validation of the foot and ankle outcome score for ankle ligament reconstruction.

We studied the validity and reliability of the Foot and Ankle Outcome Score (FAOS) when used to evaluate the outcome of 213 patients (mean age 40 years, 85 females) who underwent anatomical reconstruction of the lateral ankle ligaments with an average postoperative follow-up of 12 years (range, three to 24 years). The FAOS is a 42-item questionnaire assessing patient-relevant outcomes in five separate subscales (Pain, Other Symptoms, Activities of Daily Living, Sport and Recreation Function, Foot- and Ankle-Related Quality of Life). The FAOS met set criteria of validity and reliability. The FAOS appears to be useful for the evaluation of patient-relevant outcomes related to ankle reconstruction.

Activities of Daily Living↗

PubMed2001

Acute rupture of tendon Achillis. A prospective randomised study of comparison between surgical and non-surgical treatment.

In a prospective, randomised, multicentre study, 112 patients (99 men and 13 women, aged between 21 and 63 years) with acute, complete rupture of tendo Achillis were allocated either to surgical treatment followed by early functional rehabilitation, using a brace, or to non-surgical treatment, with plaster splintage for eight weeks. The period of follow-up was for two years. Evaluation was undertaken by independent observers and comprised interviews, clinical measurements, isokinetic muscle performance tests, heel-raise tests and an overall outcome score. The rate of rerupture was 20.8% after non-surgical and 1.7% after surgical treatment (p < 0.001). Surgical and non-surgical treatment produced equally good functional results if complications were avoided. However, the rate of rerupture after non-surgical treatment was unacceptably high.

Achilles Tendon↗

PubMed2001

Obesity-related coping and distress and relationship to treatment preference.

OBJECTIVES: The primary purpose was to define obesity-related strategies for coping with psychological problems connected with obesity. We also wanted to identify obesity-related distress and explore the effect of coping on distress. Thirdly, we wanted to investigate differences in coping and distress related to choice of surgery or conventional treatment. DESIGN: Cross-sectional data from patients in the Swedish Obese Subjects (SOS) intervention study. METHODS: An obesity-related questionnaire concerning coping and distress was created and evaluated in 2510 patients from the SOS study, using multitrait, exploratory and confirmatory factor analysis procedures. RESULTS: Three coping factors were defined. Social Trust and Fighting Spirit were problem-focused, whereas Wishful Thinking was emotion-focused. Surgical candidates displayed lower levels of problem-focused and higher levels of emotion-focused coping. We also identified two distress factors: Intrusion and Helplessness. Wishful Thinking was positively related to distress, and Social Trust and Fighting Spirit were inversely related, thus explaining the higher levels of distress reported by the surgical candidates. CONCLUSIONS: In our sample, emotion-focused coping proved maladaptive and was associated with increased distress. Problem-focused coping, however, was adaptive and associated with reduced distress. These findings partly explain psychological morbidity and should be taken into consideration in the treatment of obese people.

Adaptation, Psychological↗

PubMed2001

Workflow design as a basis for component interaction.

This paper presents a workflow case study on radiation therapy. The workflow model was developed with a conventional CASE tool aiming to effectively support further developments in respective directions of simulation, effects on organisational structures, quality assurance, component interaction and logistics of information with efficient human-computer interactions.

Computer Simulation↗

PubMed2000

Expression of specific markers and particle transport in a new human intestinal M-cell model.

The aim of this work was to establish a new, simplified in vitro model of the human M-cell. Cocultures of physically separated human intestinal epithelial Caco-2 cells and B-cell lymphoma Raji cells were established. The cocultures were characterized under the criteria of morphology, integrity, expression of M-cell markers and cell adhesion molecules (CAMs), and altered particle transport. Using this construct, the epithelial cells were transformed to cells with an M-cell-like morphology and had altered expression of potential human M-cell markers (alkaline phosphatase down-regulation and Sialyl Lewis A antigen up-regulation). The expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule was altered and there was an increased binding of lectins wheat germ agglutinin and peanut agglutinin with a 40-fold increase in microparticle transport. The particle transport was size-dependent and could be inhibited at 4 degrees C or by replacing the Raji B-cells with Jurkat T-cells. This new coculture model will enable controlled studies of M-cell development and function in vitro.

Alkaline Phosphatase↗

PubMed2000

Impairment of mitochondrial respiration after cerebral hypoxia-ischemia in immature rats: relationship to activation of caspase-3 and neuronal injury.

Mitochondrial damage may play a key role in the development of necrotic and apoptotic hypoxic-ischemic (HI) brain damage. It has previously been shown that mitochondrial respiration is depressed in the cerebral cortex after HI in neonatal animals. The aim of the present study was to further characterize the time course of the mitochondrial impairment during reperfusion and the correlation between the respiratory control ratio and brain injury and activation of caspase-3. Rat pups were subjected to unilateral carotid artery ligation and exposed to hypoxia (7.7% oxygen). Mitochondrial respiration was measured 0-72 h after HI in a mitochondrial fraction isolated from cerebral cortex. Microtubule associated protein-2 (MAP2) and caspase-3 were analyzed with immunoblotting in cerebral cortex homogenates. In addition, the time course of caspase-3 activation was measured as DEVD cleavage. The mitochondrial respiratory control ratio in cerebral cortex decreased immediately after HI followed by a partial recovery at 3-8 h. Thereafter, a secondary drop occurred with a minimum reached at 24 h of reperfusion. The secondary loss of respiratory function was accompanied by depletion of MAP2, cleavage of caspase-3 and an increased caspase-3 -like activity at 3-24 h after the insult. In conclusion, the primary phase of mitochondrial dysfunction was paralleled by a moderate decrease of MAP2 and a limited activation of caspase-3. The secondary mitochondrial impairment was associated with neuronal injury and pronounced activation of caspase-3.

Animals↗

PubMed2000

Increased survival of embryonic nigral neurons when grafted to hypothermic rats.

Hypothermia can reduce neuronal death caused by ischemia and traumatic brain injury. We therefore investigated whether mild hypothermia in rats receiving a transplant of embryonic mesencephalic rat tissue increases survival of the implanted dopaminergic neurons. Mild hypothermia (32-33 degrees C) during graft implantation and for the following 90 min significantly increased the survival of transplanted dopaminergic neurons to 171% of control values in normothermic (37 degrees C) rats. This demonstrates that treatment of the graft recipient for a relatively short period during and after surgery has a favorable effect on the survival of grafted dopaminergic neurons. These findings may be of importance for clinical neural transplantation trials which are in need of procedures that improve transplant survival.

Animals↗

PubMed2000

In vivo kinematics of total knee arthroplasty: flat compared with concave tibial joint surface.

This study evaluated the influence of the geometric configuration of the tibial joint area on the kinematics of the knee. Twenty-two patients with noninflammatory arthritis and minor preoperative deformity were studied. They each received an AMK total knee replacement with retention of the posterior cruciate ligament. Eleven patients without any knee abnormalities were used as controls. The patients were stratified to either the flat (terminology of the manufacturer: standard) or concave (terminology of the manufacturer: constrained) polyethylene insert (n = 11 in each group). Knee kinematics were assessed 1 year after the operation by having the patient ascend a platform corresponding to an extension of the knee from 50 to 70 degrees of flexion. During this motion, two film-exchangers simultaneously exposed six to 13 pairs of serial stereoradiographs. The concave geometric configuration of the tibial insert resulted paradoxically in increased anterior-posterior translations compared with the flat insert but no significant change of rotations and translations in the other directions. Compared with normal knees, the most obvious abnormality was increased anterior-posterior translations (p < 0.004). At 50 degrees of flexion, the implants with the flat tibial polyethylene insert had displaced 2 times and the concave ones had displaced 2.5 times more posteriorly than the normal knees (p < or = 0.001). Less internal tibial rotation was also recorded in the flexed positions for both types of inserts compared with the normal knees (p < 0.02). Four knees in four patients, who reported symptoms of instability and abnormal knee function, showed significantly increased proximal displacement of the center of the tibial plateau in the flexed position. The findings suggest that current prosthetic designs and surgical technique do not restore normal knee kinematics and indicate that design improvements should rely on in vivo kinematic studies.

Aged↗

PubMed2000

Additive effects of caspase inhibitor and lazaroid on the survival of transplanted rat and human embryonic dopamine neurons.

Major practical constraints on neural grafting in Parkinson's disease are the shortage of human donor tissue and the great loss of dopamine neurons during the grafting procedure. The vast majority of implanted embryonic dopamine neurons are believed to die within a few days of transplantation surgery, at least in part through apoptosis. We have previously found that survival of nigral grafts in rodents can be significantly augmented by pretreatment with the caspase inhibitor Ac-YVAD-cmk or by lazaroids (lipid peroxidation inhibitors). We now report that pretreatment with the caspase inhibitor Ac-DEVD-cmk, but not z-VAD-fmk, results in a significantly improved survival of transplanted dopamine neurons of similar magnitude to that achieved in this study using Ac-YVAD-cmk (both 220-230% of control). In addition, we found that treatment of the graft tissue with tirilazad mesylate (a lazaroid allowed for clinical use) almost doubled the survival of grafted dopamine neurons. When Ac-YVAD-cmk and tirilazad mesylate treatments were combined, the number of surviving dopamine neurons increased significantly further to 280% of control. Importantly, the same combination of neuroprotectants enhanced the survival of human dopamine neurons xenotransplanted to immunosuppressed rats (to 240% of control). In conclusion, these results suggest that combining treatments that counteract oxidative stress and caspase activation is a valuable strategy to enhance nigral graft survival that should be considered for clinical application.

Amino Acid Chloromethyl Ketones↗