Biomedical subjects

M Loew

Publications and source records attributed to M Loew.

At least 19 recordsLinked to original sources

PubMed2006

Discrimination of photon from proton irradiation using glow curve feature extraction and vector analysis.

Two types of thermoluminescence dosemeters (TLDs), the Harshaw LiF:Mg,Ti (TLD-100) and CaF(2):Tm (TLD-300) were investigated for their glow curve response to separate photon and proton irradiations. The TLDs were exposed to gamma irradiation from a (137)Cs source and proton irradiation using a positive ion accelerator. The glow curve peak structure for each individual TLD exposure was deconvolved to obtain peak height, width, and position. Simulated mixed-field glow curves were obtained by superposition of the experimentally obtained single field exposures. Feature vectors were composed of two kinds of features: those from deconvolution and those taken in the neighbourhood of several glow curve peaks. The inner product of the feature vectors was used to discriminate among the pure photon, pure proton and simulated mixed-field irradiations. In the pure cases, identification of radiation types is both straightforward and effective. Mixed-field discrimination did not succeed using deconvolution features, but the peak-neighbourhood features proved to discriminate reliably.

Algorithms↗

PubMed2006

[Intramuscular lengthening and range of motion after local tendon transfer for repair of retracted supraspinatus tendon defects. A biomechanical study].

BACKGROUND: The current cadaver study was performed to evaluate and compare infraspinatus (ISP) vs. subscapularis (SSC) tendon transfer used for the repair of a large supraspinatus (SSP) rotator cuff defect. The main outcome measures were the range of motion and intramuscular length changes during motion. METHODS: Thirteen fresh-frozen cadaver shoulders were used in the study. A supraspinatus defect extending to the apex of the humeral head (Patte size II) was created. Transosseous repair was then attempted with the ISP and with the SSC in all cases; intramuscular length changes were measured by Hall effect transducers during motion of the arm in steps of 30 degrees. RESULTS: Repair was successful in all cases when the ISP was used, while use of the SSC resulted in a successful repair in only 8 of the 13 (61.5%). Passive range of motion did not differ between ISP and SSC. ISP was shortened during flexion and abduction in contrast to the SSC that was lengthened during flexion (p<0.05) and shortened to a lesser degree (p<0.05). Length changes during rotation were not significantly different. CONCLUSIONS: In this cadaver model the ISP proved more favorable than the SSC for covering a Patte size II SSP defect if the assumption is true that lengthening of a muscle is less favorable than shortening because of the vascularization of the tendon.

Aged↗

PubMed2006

Influence of the design of the prosthesis on the outcome after hemiarthroplasty of the shoulder in displaced fractures of the head of the humerus.

We reviewed 39 patients with displaced three- and four-part fractures of the humerus. In 21 patients (group A) we had used an anatomical prosthesis for the humeral head and in 18 (group B) an implant designed for fractures. When followed up at a mean of 29.3 months after surgery the overall Constant score was 51.9 points; in group A it was 51.5 and in group B 52.4 points. The subjective satisfaction of the patients was assessed using a numerical rating scale and was similar in both groups. In group A complete healing of the tuberosities was found in 29% and 50% in group B. Partial integration was seen in 29% of group A and in only one patient in group B, while resorption was noted in 43% of group A and 44% of group B. The functional outcome was significantly better in patients with complete or partial healing of the tuberosities (p=0.022). The specific trauma prosthesis did not lead to better healing of the tuberosities. The difference in clinical outcome obtained by the two designs did not reach statistical significance.

Aged↗

PubMed2005

Incidence of rotator cuff tears in shoulder dislocations and results of therapy in older patients.

INTRODUCTION: In older patients we documented the incidence of additional injuries in shoulder dislocations in a non-randomised, prospective study and compared the results of conservative and of operative therapy of rotator cuff tears. MATERIAL AND METHODS: Between 1993 and 1999 a total of 87 patients were prospectively enrolled. In the case of documented tears of the rotator cuff in combination with symptoms persisting after conservative therapy patients were free to decide between surgical and conservative treatment. Patients were monitored for function, subjective stability, and satisfaction over a minimum follow-up period of 1 year. RESULTS: In 54% of the patients enrolled a cuff tear was documented; the frequency increased with advancing age to 100% in patients over the age of 70. Surgical treatment of the cuff tears resulted in better function and satisfaction. There were three recurrences in the conservative treatment group, while no recurrences were documented in surgically treated patients. The significant benefit of cuff repair was confirmed by regression analysis. CONCLUSION: In this selected patient group, we believe surgical repair of the symptomatic rotator cuff tear should be discussed with the patient.

Adult↗

PubMed2005

[Post-traumatic shoulder instability in adolescence].

BACKGROUND: Post-traumatic shoulder instability in adolescence represents a very rare condition. However, most of these patients develop recurrent shoulder dislocations over time. METHODS: We report about a retrospective study, which included 32 patients younger than 16 years of age. The mean follow-up was 5 years. Our evaluation focussed on patients' age at the time of first shoulder dislocation, type of injury, and the results after conservative and operative treatment. RESULTS: After the first dislocation, all shoulders were immobilized for 3 weeks and were treated with physiotherapy afterwards. Of these 32 patients, 30 (94%) developed recurrent shoulder dislocations. Eight patients remained in a conservative regimen (age <15 years) and 21 patients were operated for persistent shoulder instability (age >15 years). The recurrence rate was 8 of 21 patients (36.5%) in the operative group and 4 of 8 patients in the conservative group. At the time of follow-up, 4 of 8 conservatively treated patients had returned to their former sports activities and 15 of 21 (71%) in the operated group. CONCLUSIONS: Our results on post-traumatic shoulder instability in adolescence show high recurrence rates in both conservative and operative groups. After adolescence, including ossification of the glenoid, operative treatment is able to decrease the recurrence rate and to increase the sports ability of these young patients.

Adolescent↗

PubMed2002

Side-effects of extracorporeal shock wave therapy (ESWT) in the treatment of tennis elbow.

Apart from a few observational reports, there are no studies on the side-effects of extracorporeal shock wave therapy (ESWT) in the treatment of insertion tendopathies. Within the framework of a randomised, placebo-controlled, single-blind, multicentre study to test the effectiveness of ESWT in the case of lateral epicondylitis (LE), side-effects were systematically recorded. A total of 272 patients from 15 centres was allocated at random to active ESWT (3 x 2000 pulses, energy flux density ED(+) 0.04 to 0.22 mJ/mm(2) under local anaesthesia) or placebo ESWT. In all, 399 ESWT and 402 placebo treatments were analysed. More side-effects were documented in the ESWT group (OR = 4.3, CI = [2.9; 6.3]) than in the placebo group. Most frequently, transitory reddening of the skin (21.1%), pain (4.8%) and small haematomas (3.0%) were found. Migraine was registered in four and syncopes in three instances after ESWT. ESWT for LE with an energy flux density of ED(+) 0.04 to 0.22 mJ/mm(2) is a treatment method which has very few side-effects. The possibility of migraine being triggered by ESWT and the risk of a syncope should be taken into account in the future. No physical shock wave parameters could be definitely identified as the cause of the side-effects observed.

Adult↗

PubMed2002

[Extracorporeal shockwave therapy (ESWT) in tendinosis calcarea of the rotator cuff. Long-term results and efficacy].

Calcifying tendinitis (TC) of the rotator cuff is a transient shoulder disease with a high rate of spontaneous resorption of the deposit. Therefore, primary treatment should be conservative. In cases of persistent pain despite conservative treatment, extracorporeal shock wave therapy (ESWT) can be performed as an alternative minimally invasive method. Various short-term studies have demonstrated the efficiency of ESWT for TC. To evaluate the short- and long-term results, complications, and the number of operations avoided by ESWT, a prospective study with 115 patients was performed over a period of 4 years. The patients had received high-energy ESWT once (group A: n = 56) or twice (group B: n = 59). Six months after therapy, 47% in group A and 77% in group B showed evidence of disappearance or disintegration of the calcium deposits. Pain relief was achieved in 45% of group A and 53% of group B. Four years after treatment, 20% of the patients had undergone surgery on the involved shoulder. Of the remaining patients, 59% (68 patients) were seen for follow-up. Subjectively, 78% of group A and 87% of group B judged the treatment to be successful. X-ray examination revealed complete or partial resorption of the calcium deposit in 93% in both groups. The Constant score increased from 45 before treatment to 88 in group A and 85 in group B after treatment. ESWT was successful for about 70% of the treated patients with no long-term complications seen.

Adult↗

PubMed2002

[Etiology of rotator-cuff-tears and consequences for legal assessment].

Traumatic or degenerative etiology of rotator-cuff-tears is a matter of controversial discussion in legal proceedings. This article presents a review on the literature about current knowledge of anatomy, biomechanics and pathogenesis of rotator-cuff pathology. According to this a catalogue of potentially adequate and inadequate trauma mechanisms is proposed. Furthermore clinical history and examination as well as sonographic and radiologic findings and intraoperative pathology may help to distinguish between traumatic and degenerative changes of rotator-cuff lesions. The keypoints for and against traumatic etiology of rotator-cuff-tears are mentioned that could help the expert in the preparation of an adequate expert opinion.

Diagnosis, Differential↗

PubMed2002

Glow curve analysis applied to the discrimination of X ray versus proton irradiation.

Three types of thermoluminescence dosemeters (TLDs): LiF:Mg,Ti (TLD-100), CaF2:Tm (TLD-300), and alpha-Al2O3:C (TLD-500), were investigated for their glow curve response to separate X ray and proton irradiations. The glow curve structure for each individual TLD's exposure to the X ray and proton irradiations was analysed and compared. Distinguishable differences between the glow curve structure characteristic of each type of radiation were observed. The proton TLD-100 glow curve has revealed a complex high-temperature peak structure that was used for the proton/X ray discrimination algorithm. Proton irradiation of TLD-300 resulted in an apparent switch in the relative heights of peaks 3 and 5 as compared to X ray. In TLD-500, proton irradiation produced a more subtle difference in the glow curve with an increase in the ratio between high- and low-temperature peaks. Results demonstrate promising differences in glow curve structure present allowing for discrimination between X ray and proton radiation field exposures.

Calcium Fluoride↗

PubMed2001

Chondrocyte expressed protein-68 (CEP-68), a novel human marker gene for cultured chondrocytes.

In the search for new marker genes suitable to distinguish chondrocytes from osteoblasts and mesenchymal stem cells in culture, we have identified and characterized a novel gene called chondrocyte expressed protein-68 (CEP-68), harbouring an N-terminal leader peptide and an epidermal growth factor-like calcium-binding domain. CEP-68 defines a new family of proteins and complements collagen type II as a new marker for stem-cell-based chondrogenic tissue engineering.

Amino Acid Sequence↗

PubMed2001

Analysis of the first heart sound using the matching pursuit method.

It is acknowledged that the first heart sound S1 consists of two major, high-frequency components M1 and T1, corresponding, respectively, to the vibrations of the mitral and tricuspid valves and their surrounding tissues following valve closure in early systole. In this study, the matching pursuit (MP) method was used to decompose S1 into a series of time-frequency atoms. M1 and T1 were separated from the parameterised atoms of S1. The first two dominant frequencies of M1 were identified and used as features of a linear classifier to diagnose mitral valve abnormality. This method was applied to two sets of S1 data recorded from 15 patients with normal, and 15 patients with abnormal, bioprosthetic mitral valves, respectively. It was found that the two features exhibit significant differences between the normal and abnormal sets (p< 0.001). Using these two features, a correct classification of 93% was obtained. In addition, when the Wigner distribution of S1 was calculated from the decomposed atoms and compared with a spectrogram, the MP method provided better results. The study demonstrates that the MP method may be a promising technique for heart sound analysis.

Heart Murmurs↗

PubMed2001

[Injury pattern in shoulder dislocation in the elderly patient].

PROBLEM: Recurrent shoulder dislocation is reported to be rare in older patients. While injuries of the glenoid labrum and the anterior capsule following primary dislocation in younger patients seem to determine the rate of instability, the pattern of damages in the elderly has rarely been studied. METHODS: 91 patients with an age older than 40 years with the diagnosis of primary (group A, n = 50) or recurrent (group B, n = 41) anterior shoulder dislocation were included in a prospective study. By analysis of the findings in x-rays, MRI, CT-scans and in 36 patients of diagnostic arthroscopy the pattern of intra- and periarticular pathology was evaluated. RESULTS: While the incidence of bony Bankart- and Hill-Sachs lesions was constantly spread over the age groups the pattern of soft tissue damages was different. Up to the age of 60 years lesions of the glenoid labrum were leading while in older patients the prevalence of rotator cuff tears became about 70 percent. CONCLUSIONS: The development of secondary osteoarthritis and persisting symptoms in older patients with rotator cuff tears after traumatic shoulder dislocation requires early diagnosis and appropriate treatment.

Adult↗

PubMed2001

[Kinematics and biomechanics of the elbow joint].

An attempt has been made to describe the interaction of the different joint morphologies and the ligaments of the elbow in terms of the current literature. The physics of joint kinematics and biomechanics will be discussed and used to resolve current incomplete interpretations. The elbow is a very stable functional unit due to its bony tracking and "self-stabilising" ability especially in the humeroradial joint. In reconstruction and in total joint replacement, the different radii of curvature of the various surfaces have to be respected to redevelop full joint function.

Biomechanical Phenomena↗

PubMed2001

[Contracture of the elbow joint. Etiological review and general treatment concepts].

The contracture of the elbow joint is a symptom of various local changes and systemic disorders. Appropriate therapy requires a distinct knowledge of the relevant anatomical structures as well as of the etiology and pathogenesis of the functional restriction. Systematically, intrinsic contractures coming from the synovial membrane and intra-articular structures are distinguished from extrinsic contractures involving extra-articular soft tissues. The etiology of heterotopic ossifications is still widely unknown. The classification of the contracture is defined by the by extent of the remaining range of motion. Indications for surgery in severe cases depend on the degree of pain and of functional loss. Surgical arthrolysis includes a large spectrum of possibilities ranging from endocopical procedures to prosthetic joint replacement. Complications are relatively frequent after surgery and the individual gain of function is not always predictable.

Arthroplasty, Replacement↗

PubMed2001

Osteoporosis in patients with paralysis after spinal cord injury. A cross sectional study in 46 male patients with dual-energy X-ray absorptiometry.

In a cross-sectional study, 46 male patients with paralysis after spinal cord injury (average age 32 years; injuries sustained from 1 to 26 years ago; 33 Frankel A, 13 Frankel B, C, D) were examined clinically and by dual-energy X-ray absorptiometry (DEXA). Their bone mineral density (BMD) values were compared with age-related controls and correlated to clinical parameters. BMD was reduced in the proximal femur (p < 0.05) and the distal forearm (p < 0.05), but not in the lumbar spine. Demineralisation was influenced in the proximal femur (Z-score -2.95) by immobilisation after surgical treatment. Patients suffering from complete lesions had significantly lower BMD in the lumbar spine (-1.47) compared with patients with incomplete lesions (+0.02). BMD was not significantly influenced by the level of the lesion and the ambulatory status. Long-term monitoring showed significant demineralisation in the proximal femur (r = -0.36) and the distal forearm (r = -0.4), but not in the lumbar spine (r = -0.21). By correlating BMD with clinical parameters, it can be deduced that, firstly, immobilisation after surgical treatment should be reduced to a minimum; secondly, that every effort must be expended to prevent turning an incomplete into a complete lesion; and finally, that rehabilitation treatment should be lifelong.

Absorptiometry, Photon↗

PubMed2001

Quantitative assessment of in vitro jets based on three-dimensional color Doppler reconstruction.

Three-dimensional (3-D) color Doppler imaging of flow jets was performed to investigate the effects of flow rate and orifice size on jet volumes. Flow jets were generated using a flow model to simulate mitral regurgitation. This flow model consisted of a ventricular chamber, a valvular plate and an atrial chamber. Steady flow was driven through circular orifices having diameters of 2.5, 3.5, 4.5, and 6 mm, respectively, with flow rates of 5, 10, 15, 20, and 25 mL/s to form free jets in the atrial chamber. An ATL Ultramark 9 HDI system was used to perform 3-D color Doppler imaging of the flow jets. A transesophageal probe was rotated by a stepper motor to create 3-D color Doppler images of the jets. The color jet volumes for different hemodynamic conditions were measured and then compared with the theoretical predictions. Results showed that the jet volume estimated from the 3-D color Doppler was directly proportional to the flow rate and inversely proportional to the orifice size. The estimated jet volumes correlated well (r > 0.95) with theoretical predictions. This study supports the use of color jet volume as a parameter to quantify mitral regurgitation.

Blood Flow Velocity↗

PubMed2001

[Depressive disorders in neurologic rehabilitation: therapy with paroxetine].

OBJECTIVE: Depression is a common problem in neurological rehabilitation. Although three double-blind studies have shown the efficacy of trazodone, citalopram and nortriptyline, antidepressant drug therapy of poststroke depression is not yet considered a state-of-the-art strategy. In a hospital for neurological rehabilitation we have performed an open study on the effects of the SSRI, paroxetine, in depressive disorders caused by neurological diseases. METHOD: 111 consecutive admissions were screened for depression and 9 patients were admitted to the study having a HDRS score > or = 14. RESULTS: 10-40 mg of paroxetine were well tolerated and led to a > or = 50% reduction of the HDRS score in 8/9 patients. A patient with pathological crying, but without depression, was also successfully treated with 20 mg of paroxetine. CONCLUSIONS: We conclude that the SSRI, paroxetine, is an effective and well-tolerated therapy of depressive disorders caused by various neurological diseases, including also other diagnoses than stroke.

Adult↗

PubMed2001

Long term changes of the throwing arm of former elite javelin throwers.

The aim of this study was to determine long term changes in shoulder and elbow joints of former elite javelin throwers. Twenty-one elite javelin throwers were examined at an average of 19 years after the end of their high performance phase. Mean age at examination was 50 years. Functional assessment of both shoulders was determined by the Constant-score. The shoulder of the throwing arm was examined by magnetic resonance imaging. Both elbow joints were examined clinically and radiographically. Five athletes complained about transient shoulder pain in their throwing arm affecting activities of daily living, fourteen athletes had a deficit of internal rotation of at least ten degrees. Constant-scores of throwing arms were six points lower than those of non-throwing arms (P < 0.05). Complete ruptures and partial tears of the rotator cuff were frequent. Three athletes complained about transient elbow pain in their throwing arm affecting activities of daily living; ten athletes had a deficit of extension of more than five degrees. All dominant elbows had advanced arthrotic alterations (osteophytes, sclerosis) compared to the non-dominant side. Athletes who trained with weights of more than 3 kg had a significantly higher risk of degenerative changes than athletes who did not (P < 0.01). We therefore recommend to avoid throwing training with weights of more than 3 kg.

Activities of Daily Living↗