Biomedical subjects

J Karlsson

Publications and source records attributed to J Karlsson.

At least 73 records · Page 4Linked to original sources

PubMed2000

Evaluation of harvested and normal patellar tendons: a reliability analyses of magnetic resonance imaging and ultrasonography.

This study compared the reliability (interchangeability) of magnetic resonance imaging (MRI) and ultrasonography (US) examinations of the patellar tendon after using central third patellar tendon autografts during anterior cruciate ligament reconstruction. Nineteen consecutive patients (7 women, 12 men) underwent bilateral MRI and US of the patellar tendons 27 (24-29) months after anterior cruciate ligament reconstruction using ipsilateral central third patellar tendon autografts. Two experienced radiologists blinded to one another evaluated the examinations. Measurements of the length of the noninjured patellar tendon showed the greatest reliability between MRI and US, with no systematic difference (P=0.48), a small mean difference (-0.1 mm), and an interclass correlation coefficient of 0.74. The measurements of the thickness and width of the noninjured side were also judged as reliable. However, on the injured side a lower reliability was found between MRI and US. We conclude that MRI and US are reliable (interchangeable) methods only for evaluating noninjured patellar tendons.

Adolescent↗

PubMed2000

A clinical and radiographic comparison of absorbable and non-absorbable suture anchors in open shoulder stabilisation.

The aim of this study was to compare the clinical and radiographic results using either absorbable or non-absorbable suture anchors in patients with recurrent unidirectional, post-traumatic shoulder dislocations. All patients had a Bankart lesion. One surgeon operated on 33 consecutive patients, 27 males and six females. Group A comprised 15 shoulders and group B 18 shoulders, all of which underwent a standardised open Bankart reconstruction using 3.7-mm TAG suture anchors. In group A, absorbable anchors were used, while in group B, non-absorbable ones were used. There was one re-dislocation in each group. In group A, the Rowe and Constant scores were 89 (69-98) and 89 (76-99) points, respectively. The corresponding values in group B were 87 (44-98) (not significant; NS) and 90 (71-100) points (NS). The strength measurements revealed 8.1 (3.8-12.3) kg in 90 degrees abduction in group A and 10.0 (6.7-12.0) kg in group B. Healthy control shoulders revealed 10.2 (4.5-13.2) kg (NS A and B versus controls). The external rotation in abduction was 70 degrees (40-90) in group A and 80 degrees (40-100) in group B. The value for the controls was 90 degrees (80-120) [P < 0.001 (A versus controls), P < 0.05 (A versus B) and P < 0.001 (B versus controls)]. The radiographs revealed that 9/15 (60%) in group A and 10/15 (66%) in group B had visible drill holes or cystic formations in conjunction with the drill holes (NS). Furthermore, 11/15 (73%) in group A and 10/15 (66%) in group B had signs of minor degeneration (NS). We conclude that, in terms of stability and clinical results, no differences were found between the study groups. Both groups demonstrated a restriction in external rotation as compared with the healthy shoulders in the same cohort. On the radiographs, visible drill holes or cystic formations in conjunction with the drill holes were seen with equal frequency, regardless of whether absorbable or non-absorbable suture anchors were used.

Absorbable Implants↗

PubMed2000

Anatomical reconstruction versus tenodesis for the treatment of chronic anterolateral instability of the ankle joint: a 2- to 10-year follow-up, multicenter study.

The clinical outcome of anatomical reconstruction or tenodesis in the treatment of chronic anterolateral ankle instability was assessed in a retrospective multicenter study. The anatomical reconstruction group (group A) consisted of 106 patients (mean age at operation 24 +/- 8.4 years) and the tenodesis group (group B) of 110 patients (mean age at operation 26 +/- 11.4 years). Patients were evaluated at a mean follow-up of 5.5 +/- 2.8 years in group A and 5.2 +/- 2.9 years in group B. The review protocol included patient characteristics, physical examination, two ankle scoring scales to evaluate the functional results, and standard anteroposterior and lateral radiographs to evaluate degenerative changes. Mechanical stability was evaluated using standardized stress radiographs. A larger number of reoperations was performed in group B (P = 0.008). At physical examination, more patients in group B had a smaller range of ankle motion than those in group A (P = 0.009). A larger proportion of patients in group B had medially located osteophytes, as seen on standard radiographs (P = 0.04). On stress radiographic examination, the mean talar tilt (P = 0.001) and mean anterior talar translation (P < 0.001) were seen to be significantly greater in group B than in group A. There were no differences in mean Karlsson score between the groups, but more patients in group A had an excellent result on the Good score (P = 0.011). Unlike anatomical reconstructions, tenodeses do not restore the normal anatomy of the lateral ankle ligaments. This results in restricted range of ankle motion, reduced long-term stability, an increased risk of medially located degenerative changes, a larger number of reoperations, and less satisfactory overall results.

Adolescent↗

PubMed2000

A comparison of results in middle-aged and young patients after anterior cruciate ligament reconstruction.

The aim of this retrospective study was to compare the results after arthroscopic anterior cruciate ligament (ACL) reconstruction in middle-aged and young patients. From our database (including 604 patients with a follow-up rate of 95%), we extracted all the patients over 40 years of age (group A, n = 30) and compared them with a group of patients from the same material, aged between 20 and 24 years (group B, n = 37). The groups were comparable in terms of the male:female ratio and surgical techniques. The follow-up was performed by independent observers. The median follow-up period was 31 months (range, 22 to 60 months) in group A and 38 months (24 to 60 months) in group B (P =.014). Before injury, the Tegner activity level was 6 (4-9) in group A and 9 (4-9) in group B (P <.001). At follow-up, the Tegner activity level was 5 (3-9) in group A and 6 (3-9) in group B (P =.032). At the follow-up, there was no difference in terms of the Lysholm score, which was 91 (37-100) and 89 (38-100) points in group A and group B, respectively. Using the IKDC evaluation system, 10 patients (33%) were classified as normal, 12 (40%) as nearly normal, 6 (20%) as abnormal, and 2 (7%) as severely abnormal in group A, compared with 8 (22%) normal, 18 (48%) nearly normal, 10 (27%) abnormal, and 1 (3%) severely abnormal in group B (NS). The 1-leg hop quotient was 90% (52-167) in group A and 93% (70-118) in group B (P =.056). The KT-1000 measurement showed an anterior side-to-side laxity difference of 2.0 mm (-4 to 8.5 mm) in group A and 2.0 mm (-2.5 to 8.0 mm) in group B (not significant). The middle-aged patients were subjectively more pleased with the results than the younger patients. There were no differences in either early or late complications between the groups. At the index operation, 11 of 30 patients (37%) in group A and 1 of 37 (3%) in group B had cartilage lesions or degenerative changes (P <.001). Age does not appear to disqualify middle-aged patients with symptomatic ACL tears from undergoing reconstruction.

Adult↗

PubMed2000

Biological treatment of joint cartilage damage.

The structure and composition of articular cartilage provides unique mechanical properties which effectively dampen and distribute loads during weightbearing. Acute traumatic damage to the articular cartilage destroys the original structure and composition of the articular cartilage and impairs its function. Lesions in articular cartilage can cause patients severe disabling symptoms from the affected joint. These symptoms also run the risk of developing into degenerative osteoarthrosis with time. Unfortunately, articular cartilage does not have any real ability to heal itself after injury. Different treatment methods have been developed in an attempt to restore the function of the injured joint and to prevent further deterioration in the articular cartilage. Some of these methods have produced promising results in clinical studies, but further research is necessary to establish their efficacy and indications for treatment. Today, no controlled studies that compare these different methods are available.

Animals↗

PubMed2000

Psychometric properties and factor structure of the Three-Factor Eating Questionnaire (TFEQ) in obese men and women. Results from the Swedish Obese Subjects (SOS) study.

OBJECTIVE: To evaluate the construct validity of the Three-Factor Eating Questionnaire (TFEQ) in obese men and women. SUBJECTS: A total of 4377 middle-aged, obese subjects in the Swedish Obese Subjects (SOS) study. METHODS: The total sample was randomly split into two data subsets and psychometric testing was performed separately in each sample. Multitrait/multi-item analysis was conducted to test scaling assumptions and factor analysis was used to test the factor structure. Measures of mental well-being (MACL, HAD) were used for testing criterion-based validity. RESULTS: The Cognitive Restraint factor was consistently reproduced and scaling analysis demonstrated strong item-scale discriminant validity, while the item-scale convergent validity was unsatisfactory. The internal structure of the Disinhibition scale was weak. Most Disinhibition and Hunger items grouped in one global factor labeled Uncontrolled Eating. A third cluster containing items on Emotional Eating was also identified. The obtained three-factor structure was cross-validated and replicated across subgroups by gender, age and BMI. CONCLUSION: The original TFEQ factor structure was not replicated. A short, revised 18-item instrument was constructed, representing the derived factors of Cognitive Restraint, Uncontrolled Eating and Emotional Eating. The most efficient items were used to boost both the convergent and discriminant validity of the scales.

Adult↗

PubMed2000

trans-resveratrol protects embryonic mesencephalic cells from tert-butyl hydroperoxide: electron paramagnetic resonance spin trapping evidence for a radical scavenging mechanism.

In recent years, the antioxidant and other pharmacological properties of resveratrol, a natural product present in grapes and wine, have attracted considerable interest from the biomedical research community. In an examination of the potential neuroprotective properties of the compound, we have investigated the ability of resveratrol to protect rat embryonic mesencephalic tissue, rich in dopaminergic neurones, from the prooxidant tert-butyl hydroperoxide. Using the electron paramagnetic resonance (EPR) spin-trapping technique, the main radicals detected in cell suspensions were the tert-butoxyl radical and the methyl radical, indicating the one-electron reduction of the peroxide followed by a beta-scission reaction. The appearance of EPR signals from the trapped radicals preceded the onset of cytotoxicity, which was almost exclusively necrotic in nature. The inclusion of resveratrol in incubations resulted in the marked protection of cells from tert-butyl hydroperoxide. In parallel spin-trapping experiments, we were able to demonstrate the scavenging of radicals by resveratrol, which involved direct competition between resveratrol and the spin trap for reaction with the radicals. To our knowledge, this is the first example in which cytoprotection by resveratrol has been demonstrated by EPR spin-trapping competition kinetics to be due to its scavenging of the radicals responsible for the toxicity of a prooxidant.

Animals↗

PubMed2000

Intraarticular morphine after arthroscopic ACL reconstruction: a double-blind placebo-controlled study of 40 patients.

We compared analgesic effects and pharmacokinetics of intraarticular versus intravenous administration of morphine after arthroscopic anterior cruciate ligament surgery. In a double-blind placebo-controlled study, 40 patients were randomly allocated to one of four treatment groups. Group I received 1 mg morphine intraarticularly and saline intravenously; group II received 5 mg morphine intraarticularly and saline intravenously; group III received 5 mg saline intraarticularly and morphine intravenously and group IV, the control group, received saline both intraarticularly and intravenously. The pain scores were significantly lower in groups I and II at 24 hours postoperatively than in group IV, and in group II during the rest of the postoperative period, as compared to groups III and IV. After intraarticular injection of 1 mg and 5 mg morphine, respectively, low concentrations of morphine-6-glucuronide (M6G) were found in the circulation, while morphine-3-glucuronide (M3G) appeared late after the injection in concentrations that considerably exceeded those of morphine in groups I and II. The analgesic effect of intraarticular morphine together with the low levels of morphine and morphine-6-glucuronide in plasma further strengthens the view that opioids have a peripheral mechanism of action.

Adolescent↗

PubMed2000

Function after Achilles tendon rupture in the elderly: 25 patients older than 65 years followed for 3 years.

We retrospectively analyzed the function after Achilles tendon rupture in 25 patients older than 65 years, 3 (1-5) years after the initial treatment. The patients' median age at the time of injury was 71 (65-86) years. The initial management was surgical in 14 patients and non-surgical (8-week immobilization) in 10, 1 patient was not treated. The ratio of the number of heel-raises on the injured to the uninjured side was median 0.64 (0-1.14), showing a reduction in performance. However, in both surgically- and non-surgically-treated patients, the subjective impairment was mild, and the patients were able to perform most walking activities. Only 9 patients reached their previous activity level. Co-morbidity was frequent: 17 patients had other diseases that affected their performance. 14 complications occurred in 11 patients. 5 patients sustained a rerupture (4 following initial closed treatment with plaster), 1 a deep venous thrombosis and 4 had superficial infections requiring antibiotic treatment. 1 patient sustained a fibular nerve injury following compression by the plaster cast and another a sural nerve injury during the operation. 2 patients had symptoms due to adhesions between the tendon and the skin. We conclude that Achilles tendon rupture in patients older than 65 years reduces lower limb function and that complications are common following surgical and non-surgical treatment.

Achilles Tendon↗

PubMed2000

Sequencing of the Francisella tularensis strain Schu 4 genome reveals the shikimate and purine metabolic pathways, targets for the construction of a rationally attenuated auxotrophic vaccine.

Francisella tularensis is the etiological agent of tularemia, a serious disease in several Northern hemisphere countries. The organism has fastidious growth requirements and is very poorly understood at the genetic and molecular levels. Given the lack of data on this organism, we undertook the sample sequencing of its genome. A random library of DNA fragments from a highly virulent strain (Schu 4) of F. tularensis was constructed and the nucleotide sequences of 13,904 cloned fragments were determined and assembled into 353 contigs. A total of 1.83 Mb of nucleotide sequence was obtained that had a G+C content of 33.2%. Genes located on plasmids pOM1 and pNFL10, which had been previously isolated from low virulence strains of F. tularensis, were absent but all of the other known F. tularensis genes were represented in the assembled data. F. tularensis Schu4 was able to grow in the absence of aromatic amino acids and orthologues of genes which could encode enzymes in the shikimate pathway in other bacteria were identified in the assembled data. Genes that could encode all of the enzymes in the purine biosynthetic and most of the en- zymes in the purine salvage pathways were also identified. This data will be used to develop defined rationally attenuated mutants of F. tularensis, which could be used as replacements for the existing genetically undefined live vaccine strain.

Bacterial Vaccines↗

PubMed2000

Preoperative skin traction in patients with hip fractures is not useful.

One hundred twenty patients with cervical or trochanteric hip fractures were allocated randomly to groups receiving either skin traction or no special treatment while awaiting surgery. No differences were found between the groups in terms of pain experienced, the need for supplementary analgesics, or complications during the hospital stay. In addition, the repositioning and percentage of united fractures after 4 months did not differ significantly between the groups. The application of skin traction offered no benefits, and thus routine use of preoperative skin traction in patients with hip fractures is not recommended.

Aged↗

PubMed2000

Data mining and structuring of executable data analysis reports: guideline development and implementation in a narrow sense.

In this paper we present a data mining scenario that supports development of automated web-based documentation of data analysis for diagnosis and treatment. The documents can be seen as guidelines in a narrow sense, and are designed to include executable modules for the corresponding decision support systems. Our aim is to discuss the possibilities of identifying certain types of diagnoses and treatments for which guidelines can be generated and computerised more systematically.

Artificial Intelligence↗

PubMed1999

9-cis-retinoic acid in combination with retinal pigment epithelium induces apoptosis in cultured retinal explants only during early postnatal development.

Retinoic acid is one of the active metabolites of vitamin A and has profound effects on the development of the CNS including retina. Previously, we have shown that rod-specific apoptosis is induced in retinal explants from neonatal mice by exposure to 9-cis-retinoic acid (9CRA) when the retinal pigment epithelium (RPE) is present. In explants lacking RPE, it instead has a differentiation-promoting effect seen as an accelerated opsin expression on postnatal day 3. To investigate the long-term effect of 9CRA exposure, we have explanted retinas from neonatal C3H mice with or without RPE attached and placed in organ culture. After 19 or 48 h in culture or 7, 8 or 13 days in culture, the explants were either fixed for histochemical examination or frozen for assay of DEVDase activity. We found that long-term exposure to 9CRA caused a decrease in the number of cell layers in the outer nuclear layer (ONL) only in explants with the RPE attached. When explants with RPE attached were exposed to 9CRA only during the second postnatal week, neither an increase in DEVDase activity, TUNEL-positive cells, nor a decrease in cell layers of the ONL could be demonstrated, indicating that the retina was insensitive to the apoptosis-inducing effect of 9CRA after the first postnatal week. The absence of RPE in control explants resulted in a higher number of rosettes and the extrusion of cells into the subretinal space.

Aging↗

PubMed1999

Effects of anaesthetics and lazaroid U-83836E on survival of transplanted rat dopaminergic neurones.

We investigated whether different methods of anaesthesia, used on the pregnant rat when collecting embryonic donor tissue, and a lipid peroxidation inhibitor (lazaroid U-83836E) affect the survival of grafted embryonic dopaminergic neurones in hemiparkinsonian rats. There was no difference in either functional recovery or survival of dopaminergic neurones between the different euthanasia groups: (a) isoflurane sedation followed by cervical dislocation, (b) equithesin- or (c) euthatal-anaesthesia. However, lazaroid-treatment enhanced both behavioural recovery and transplant survival.

Anesthetics, Combined↗

PubMed1999

Role of a novel photosystem II-associated carbonic anhydrase in photosynthetic carbon assimilation in Chlamydomonas reinhardtii.

Intracellular carbonic anhydrases (CA) in aquatic photosynthetic organisms are involved in the CO2-concentrating mechanism (CCM), which helps to overcome CO2 limitation in the environment. In the green alga Chlamydomonas reinhardtii, this CCM is initiated and maintained by the pH gradient created across the chloroplast thylakoid membranes by photosystem (PS) II-mediated electron transport. We show here that photosynthesis is stimulated by a novel, intracellular alpha-CA bound to the chloroplast thylakoids. It is associated with PSII on the lumenal side of the thylakoid membranes. We demonstrate that PSII in association with this lumenal CA operates to provide an ample flux of CO2 for carboxylation.

Algal Proteins↗

PubMed1999

Patterns of cell death and dopaminergic neuron survival in intrastriatal nigral grafts.

Previous studies indicate that 80-95% of grafted dopamine neurons die following implantation of embryonic ventral mesencephalic tissue into the striatum. It is believed that the majority die within the first 1-3 weeks after surgery. The aim of this study was to study when and where the implanted neurons die, using the novel fluorescent stain Fluoro-Jade. Fluoro-Jade has recently been shown to stain cell bodies, dendrites, axons, and terminals of degenerating neurons. We transplanted dissociated ventral mesencephalic tissue from embryonic day 14 rat embryos into intact adult rat striatum. After perfusion and sectioning of the implanted rat brains, the number and distribution of Fluoro-Jade and tyrosine hydroxylase-positive neurons were evaluated at 6, 10, 14, and 42 days posttransplantation. Intensely Fluoro-Jade stained neurons were numerous in the grafts at 6 and 10 days after graft surgery; appeared in reduced numbers at 14 days; and had disappeared by the 42-day time point. The number of surviving tyrosine hydroxylase-positive, dopaminergic neurons in the grafts did not change between 6 and 42 days and the low survival rate confirmed that over 90% of these neurons had died during the first week. Assessment of the distribution of neurons positive for Fluoro-Jade or tyrosine hydroxylase revealed higher numbers of neurons stained for these markers located at the periphery than the center of the grafts, and this pattern did not change over time. This study indicates that transplanted neurons continue to die up to 14 days after grafting. Since the majority of transplanted tyrosine hydroxylase-positive neurons most probably die before 6 days after transplantation, neuroprotective strategies should primarily focus on the transplantation procedure and the first week after implantation.

Animals↗

PubMed1999

Complications following arthroscopic anterior cruciate ligament reconstruction. A 2-5-year follow-up of 604 patients with special emphasis on anterior knee pain.

The aim of the study was to assess knee function after arthroscopic anterior cruciate ligament reconstruction and to analyse complications impeding rehabilitation, additional surgery until the final follow-up, as well as residual patellofemoral pain and donor-site problems. Between 1991 and 1994, 635 patients were operated on using patellar tendon autografts and interference screw fixation. Of these, 604 (95.1%) patients (403 male and 201 female) were re-examined by independent observers at the final follow-up 38 (range 21-68) months post-operatively. The Lysholm score was 85 (range 14-100) points and the Tegner activity level was 6 (range 1-10). Using the IKDC score, 206 patients (34.1%) were classified as normal, 244 (40.4%) as nearly normal, 122 (20.2%) as abnormal and 32 (5.3%) as severely abnormal. In patients with an uninjured contralateral knee (n = 527), the KT-1000 revealed a total side-to-side difference of 1.5 (range -7-11) mm, and 384/527 (72.9%) had a side-to-side difference of < or = 3 mm. The one-leg-hop test was 95% (range 0%-167%). One or more complications impeding rehabilitation were recorded in 184/604 patients (30.5%). The most common was an extension deficit (> 5 degrees), in 81 patients (13.4%). During the period until the final follow-up, 196 re-operations were performed in 161/604 (26.7%) patients. More than one re-operation was required in 27 patients. Shaving and anterior scar resection due to extension deficit were the most common procedures performed (on 65 occasions). Moderate to severe subjective anterior knee pain related to activity, walking up and down stairs, and sitting with the knee flexed was found in 203/604 patients (33.6%). The median loss of anterior knee sensitivity was 16 (range 0-288) cm2. Patients with a full range of motion had less anterior knee pain than patients with isolated flexion or extension deficits, or combined flexion and extension deficits (P < 0.05, P = 0.08 and P < 0.001, respectively). Patients with a full range of motion had less anterior knee pain than patients with extension deficits (with and without flexion deficits) (P < 0.001). Patients with a full range of motion and a minimal loss (< or = 4 cm2) of anterior knee sensitivity had significantly (P < 0.01) less subjective anterior knee pain than patients who did not fulfil these criteria. A considerable number of complications hindering the rehabilitation and conditions requiring additional surgery until the final follow-up were recorded. Anterior knee pain and problems with knee-walking were correlated with the loss of range of motion and anterior knee sensitivity.

Adolescent↗

PubMed1999

Serial magnetic resonance imaging of the donor site after harvesting the central third of the patellar tendon. A prospective study of 37 patients after arthroscopic anterior cruciate ligament reconstruction.

The aim of this prospective study was to follow the development of repair tissue in the donor-site area using serial magnetic resonance imaging (MRI) evaluation and to assess whether the MRI findings were correlated with donor-site morbidity. Thirty-seven consecutive patients with unilateral anterior cruciate ligament injuries undergoing elective reconstruction of the ligament were included in the study. They were aged 27 (range 14-50) years. The graft was harvested through two 25-mm vertical incisions with the aim of protecting the infrapatellar nerve and sparing the paratenon. The tendon defect was left open. The patients underwent MRI evaluation at 6 weeks, 6 months and 27 months postoperatively. A final clinical follow-up was made 25 (range 23-29) months postoperatively. MRI demonstrated that the donor-site gap, i.e. the area corresponding to a pathological non-tendinous-like tissue signal, was 9 (range 4-18) mm at 6 weeks, 5 (range 2-14) mm at 6 months and 2 (range 0-5) mm at 27 months. The size of the donor-site gap had significantly decreased at 6 months compared with 6 weeks (P = 0.0001), as well as at 27 months compared with 6 months (P = 0.0001). We conclude that the patellar tendon at the donor site healed gradually, as expressed by a decrease in the area of non-tendinous-like tissue signal on the serial MRI evaluations.

Adolescent↗