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Biomedical subjects

F Mayer

Publications and source records attributed to F Mayer.

At least 73 records · Page 4Linked to original sources
PubMed1999

Metabolic and cardiocirculatory reactions after concentric and eccentric exercise of the shoulder.

Lower metabolic and cardiocirculatory reactions to eccentric compared to concentric exercise are known for large muscle groups. The extent of exercise reaction depends on the muscle mass involved and moreover differs between the various muscle groups, while it is unclear to which extent cardiovascular and metabolic reactions and differences between the types of work exist in the shoulder, also it is not known whether these reactions differ according to training status. Lactate production (LA), heart rate (HR), and blood pressure (BP) were examined following eccentric and concentric shoulder movements in 16 male gymnasts (GN) and 15 male untrained subjects (US). Differentiation was made according to the types of work for peak torque (PT) and local muscle endurance (LME). Following eccentric exercise, the increase of LA and HR was clearly lower than following concentric exercise (p<0.05). No difference was observed between the groups. Diastolic BP showed no changes, whereas systolic BP was higher following concentric exercise. Eccentric PT was higher than concentric PT in GN within a test-retest variability of 15%. LME showed a lower degree of fatigue under eccentric conditions, independent of the group. It is concluded that eccentric exercise of the shoulder leads to lower metabolic and cardiocirculatory reactions than concentric exercise, in spite of higher peak torque and less fatigue. Exercises consisting of a high proportion of eccentric movement may thus be beneficial in the therapy of shoulder complaints, especially in patients with cardiovascular disease.

Adult↗
PubMed1999

Ventilatory, lactate-derived and catecholamine thresholds during incremental treadmill running: relationship and reproducibility.

Anaerobic threshold as a basic criterion of training recommendation can be estimated by various parameters. The purpose of this study was to investigate the relationship and the reproducibility of ventilatory, lactate-derived and catecholamine thresholds of an incremental treadmill exercise. Therefore, 11 male subjects underwent two incremental treadmill tests within 7 days. The lactate threshold (LT) was determined at the lowest value of the lactate-equivalent (ratio lactate/performance). The individual anaerobic threshold (IAT) was calculated at LT+1.5 mmol/L lactate. The ventilatory thresholds, using mass-spectrometry, were defined by the V-slope method (AT) and at the deflection point of end-tidal CO2 (ET-CO2) concentration (RCP). The thresholds of epinephrine (TE) and norepinephrine (TNE) were calculated in the manner of LT. The running velocities were highly reproducible at LT (test-retest correlation coefficient r=0.90), IAT (r=0.97), AT (r=0.88) and RCP (r=0.95). By contrast TE (r=0.49) and TNE (r=0.46) showed a poor reproducibility. TE and TNE occurred 5-11% below LT and AT with a low correlation to LT and AT. LT was found 4% below AT, both were correlated with r=0.70 (p<0.01, test 1) and r=0.95 (p<0.01, test 2). IAT occurred 7-8% above RCP, in both tests a close correlation was found between IAT and RCP of r=0.97 (p<0.01). In summary, the ventilatory and lactate-derived thresholds show a high and similar reproducibility, but the catecholamine threshold does not. In the present exercise protocol, there are systematic differences between the lactate-derived and ventilatory thresholds, in spite of a close relationship, and these must be taken into account in recommendations derived for training.

Adult↗
PubMed1999

The influence of age on isokinetic torque of the upper and lower leg musculature in sedentary men.

While strength patterns in aging for the knee joint have been well investigated in the concentric mode, few data are available about the behaviour in the eccentric mode and for either modus in the ankle. The purpose of this study was to compile reference data for the lower extremities in untrained men between 20 and 60 years of age to determine the influence of age, especially in the eccentric work mode. Sixty-four male subjects between 20 and 60 years were divided into four age groups. Using a LIDO ACTIVE dynamometer, maximum torque was tested for the knee between 90 degrees to 0 degrees and for the ankle between 30 degrees to -10 degrees at velocities 60, 180, 240, 300 degrees/s concentric, 60 and 120 degrees/s eccentric and isometric with angles 15 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees for the knee and 30 degrees, 20 degrees, 10 degrees, 0 degrees , -10 degrees for the ankle. Individual parameters for age-dependence were checked using linear correlation calculation with p < 0.01 set as significant. The peak torque (PT) of the knee extensors and flexors showed a typical course with the highest values in the eccentric and isometric mode and a decrease in the concentric mode with increasing angular velocity. In the concentric mode there was a significant negative correlation between PT and age at all angular velocities, but none for isometric and eccentric mode. The greatest maximum torque in the ankle was attained in the eccentric mode at 60 degrees/s. The difference to the knee was smallest in this mode compared to isometric and concentric. The plantar flexion showed age-dependence at all concentric velocities, less in eccentric and none in isometric mode. There was no correlation in dorsiflexion. The influence of loss of muscle fiber and degeneration in the course of aging has thus less influence in eccentric measurements than in the concentric mode. On the contrary, it must be assumed that the high eccentric tensions which are possible due to the quasi-elastic structures in the muscle, are maintained by the increase in stiffness of the connective tissue.

Adult↗
PubMed1999

[Muscle strength after surgical treatment of ruptures of the long biceps tendon by refixation to the short head].

Operative treatment for ruptures of the long biceps tendon still is discussed controversially. In the present literature surgical repair is advised for sporting and high demand patients due to favourable functional results and low loss of strength. Until now only few objective and reproducible results were published. In the present literature the keyhole-technique is recommended due to favourable bio-mechanical conditions. To evaluate postoperative strength 19 patients were investigated after an average follow-up of 6.5 years, by clinical examination and isokinetic measurement. Compared with the non-operated shoulder isokinetic determination of isometric maximal peak torque and strength during concentric stress for elbow-flexion, shoulder-abduction and shoulder-flexion yield to almost identical results for the operated shoulder. According to the criteria of the Constant-Score all patients achieved very good and good results. Refixation to the short head can be advised for treatment of ruptures of the long biceps tendon due to the certain technique with a low complication rate and very good functional outcome.

Adult↗
PubMed1999

Mitomycin C continuous infusion as salvage chemotherapy in pretreated patients with advanced gastric cancer.

UNLABELLED: Our purpose was to evaluate the safety and therapeutic activity of continuously infused mitomycin C in patients with recurring or progressive metastatic gastric cancer following first-line chemotherapy. Patients were treated with mitomycin C 20 mg/m2 i.v. over a time period of 120 h followed by a 3-week rest period. All patients received prednisone 50 mg p.o. prophylactically for 5 days to prevent hemolytic uremic syndrome and pulmonary side effects. Twenty-two consecutively enrolled patients were assessable for toxicity and 20 for response evaluation completing at least one full course of chemotherapy (two patients evaluable but not measurable). PATIENT CHARACTERISTICS: median age: 63 years (39-76); Sex (M/ F): 13/9; median Karnofsky status: 70% (50-100%); resection of primary tumor n = 12 (55%); sites of metastases: liver n = 17 (77%), locally advanced n = 10 (45%), peritoneum n = 13 (59%), lungs n=5 (23%), bone n=3 (14%) and lymph nodes n=14 (64%). Previous chemotherapy regimens: bolus 5-FU/folinic acid n=6 (27%), ELF n=4 (18%), EAP n=3 (14%) and continuous 5-FU/folinic acid/cisplatin/paclitaxel n=9 (41%). In 20 evaluable patients one complete and five partial remissions were observed; overall response rate 30.0% [95% confidence interval (CI): 9.1-50.9%] with a median response duration of 2.1 months (range: 2-6). The median survival was 3.6 months (95% CI: 2.1-6.0) resulting in a 6-month survival rate of 30% since start of mitomycin C. WHO grade III/IV mucositis, diarrhea and fever/infection occurred in 9% of patients each. Cumulative thrombo- and leukocytopenia (WHO grade II/IV) were observed in four and two patients, respectively. Treatment had to be stopped early in two patients. No severe renal dysfunction, pulmonary toxicity or evidence of hemolytic uremic syndrome was observed. Fatigue during the 120 h infusion of mitomycin C was common (11 of 22 patients). We conclude that continuous infusion of mitomycin C is feasible on an outpatient basis, revealing an acceptable toxicity. Mitomycin C demonstrates single-agent activity in pretreated gastric cancer, but has only limited efficacy following cisplatin/paclitaxel-based first-line chemotherapy.

Adult↗
PubMed1999

Bilateral segmental dystonia in a professional tennis player.

Dystonias occur frequently as repetitive movements, persistent elevations of muscle tone, or tonic contortions, whereby the cause is assumed to be an impairment of basal ganglia function. Focal dystonias are especially known in musicians, although little is reported on focal dystonias in athletic stress. The present case report describes the case of a 34-yr-old professional tennis player with bilateral segmental dystonia. The symptoms were expressed in involuntary movements when he intended to hit the ball and in a progredient tremor, initially in one hand, later in both, making him unable to write. The altered mobility during athletic stress was confirmed by video analysis, the altered innervation with excessive, uncoordinated impulse influx by means of electromyography during sport-type specific stress, and writing incapacity during a writing test. The symptoms abated under therapy with trihexyphenidyl-HCL, so that the patient has been able to work as a tennis coach with improved athletic performance for the past 3 yr. It is concluded that the various forms of dystonia should be included in the differential diagnosis of impaired coordinative movements under athletic exercise, especially of the upper extremities.

Adult↗
PubMed1999

[Phototherapeutic keratectomy in the treatment of Groenouw's type I corneal dystrophy].

PURPOSE: This study was designed to investigate the therapeutic potential of phototherapeutic keratectomy (PTK) for the treatment of corneal granular dystrophy. PATIENTS AND METHODS: PTK was performed with the Excimed UV 200, (Summit Technology, Inc) on a series of 27 eyes of 22 patients with corneal granular dystrophy. Mean patients' age was 34.6 years. The mean follow-up period was 31 months (ranged from 6 to 52 months). The changes in best corrected visual acuity and spherical equivalent were evaluated at 6, 12, 18 and 24 months. RESULTS: All of patients achieved visual improvement. Mean preoperative best corrected visual acuity (BCVA) was 20/100 and mean postoperative BCVA was 20/30 at one year. The mean hyperopic shift caused by tissue ablation was +/- 2.8 D after one year. CONCLUSION: Corneal grafting was the standard treatment for visually disabling granular dystrophy, but PTK has significant advantages over this procedure and must now be the standard method of managing corneal granular dystrophy when intervention is required.

Adult↗
PubMed1999

UFT/calcium folinate plus weekly paclitaxel for solid tumors.

Since cancer is incurable in many patients, palliation of symptoms and quality-of-life issues are important aspects of therapy. Uracil and tegafur (UFT) plus calcium folinate are the components of the oral agent known as Orzel, which offers activity comparable to intravenously administered 5-fluorouracil (5-FU) combined with calcium folinate. Paclitaxel (Taxol), administered intravenously on a weekly schedule, offers high dose intensity and high response rates with limited hematologic toxicity. It is the aim of this phase I study to define the dose-limiting toxicity, possible antitumor activity, and appropriate phase II study dose for the combination of UFT plus calcium folinate administered orally for 4 weeks plus weekly doses of paclitaxel. The daily dose will be fixed at UFT 300 mg/m2 plus calcium folinate 90 mg, both divided into three doses per day; paclitaxel will be escalated in each cohort of patients in 10-mg/m2 steps, starting with 50 mg/m2 weekly. This protocol will take the success of protracted 5-FU infusion--here achieved orally with UFT plus calcium folinate--in combination with paclitaxel one step further by using paclitaxel in a dose-dense, less toxic weekly schedule. It may be anticipated that an active outpatient therapy for a variety of solid tumors will result.

Adolescent↗
PubMed1998

Structure of the Na+-driven flagellum from the homoacetogenic bacterium Acetobacterium woodii.

The Na+-dependent flagellum of Acetobacterium woodii was characterised. Flagellin and whole flagella were purified and analysed by SDS-PAGE and electron microscopy. The structure and dimensions of the filament and the hook-basal body, as revealed by electron microscopy, resemble those of H+-dependent flagella from gram-positive bacteria. Intramembrane particle rings were present at the cell pole in freeze-fractured A. woodii cells, which might correspond to the mot complex.

Bacterial Proteins↗
PubMed1998

Immunoelectron microscopic studies indicate the existence of a cell shape preserving cytoskeleton in prokaryotes.

Immunoelectron microscopic studies of prokaryotes were performed with anti-actin antibodies directed against the C terminus of actin. Studies on ultrathin sections revealed high proportions of the overall label close to the cell periphery in Escherichia coli, Ralstonia eutropha, Thermoanaerobacterium thermosulfurigenes, T. thermosaccharolyticum, and Methanococcus jannaschii. Substantial label also in the cytoplasm was observed in Bacillus sp., Methanococcus voltae, and Methanobacterium thermoautotrophicum. Only very minor amounts of label were found in the nucleoid region of the cells. Whole-mount immunogold studies, combined with negative staining, revealed the existence of an intracellular network of fibrils which could be labeled by anti-actin antibodies. This network is assumed to be located below the cytoplasmic membrane all around the cytoplasm. It appears to have properties that would allow its function as a cytoskeleton-like structure preserving cell shape.

Actins↗
PubMed1998

Confocal microscopy of cystic disorders of the corneal epithelium.

OBJECTIVE: This study aimed to describe the morphology of cystic disorders of the corneal epithelium by confocal microscopy. DESIGN: The study design was a prospective evaluation of confocal microscopic images of patients with cystic corneal disorders. PARTICIPANTS: Thirteen patients (19 eyes) were included. The corneal disorders included four patients with corneal decompensation (Fuchs' dystrophy), five patients with epithelial basement membrane dystrophy (e.g., Cogan's microcystic and map-dot dystrophies), one patient with Meesmann's dystrophy, and three patients with recurrent erosion syndrome of unknown etiology. Confocal images of diseased corneas were compared with those of ten normal control eyes (ten subjects). INTERVENTION: All patients were examined by slit-lamp biomicroscopic analysis and confocal microscopic analysis (Tomey, Erlangen-Temmenlohe, Germany). Image analysis was used to identify the corneal epithelial structures correlated with the corresponding pathology. MAIN OUTCOMES MEASURES: Confocal microscopy was used to assess the size, shape, light scatter, and reflection of the cysts. RESULTS: Slit-lamp examination results showed corneal epithelial cystic lesions in all cases. Confocal microscopy was able to identify cystic lesions in 9 (69.2%) of 13 patients. Of the four patients in whom lesions could not be found by confocal microscopy, three had recurrent erosion syndrome and the other one had epithelial basement membrane dystrophy. The confocal images were compatible with the clinical and histologic pictures of the disease. Normal control eyes did not show any epithelial lesion, either by biomicroscopy or confocal microscopy. CONCLUSIONS: Confocal microscopy provides an in vivo evaluation of cystic epithelial corneal lesions. This study shows that confocal microscopy is suitable for examining cystic lesions of the corneal epithelium. Nevertheless, it is not as sensitive as biomicroscopy in detecting cystic lesions in certain corneal conditions.

Corneal Diseases↗
PubMed1998

[Traumatology and sports injuries in equestrian acrobatics in the adolescent].

The objective of this study was to compile knowledge of athletic injuries and complaint patterns related specifically to equestrian acrobatics (e.a.). A 20-page standardized questionnaire was sent to 114 e.a. participants. The mean age of the participants in e.a. groups was 15 +/- 3 years, that of independent participants 21 +/- 3 years. A total of 489 injuries was reported, mainly to muscles and tendons (35%), skin (33%) and joints and ligaments (25%). Bone injuries (6%) and head injuries (2%) were infrequent. Analysis of the localization showed that the head-face-neck region was involved in the injury in 3.9%, the torso in 5.5%, the upper extremities in 28%, pelvis and hip region in 3.9%, and the lower extremities in 52%. More than half the injuries were categorized in severity grade I (55%) (not requiring medical attention), 25% were grade II (single medical treatment), 15% grade III (several outpatient medical treatments) and 5% grade IV (requiring hospitalization). Nearly half of the injuries to the lower extremities resulted from jumping exercises, while the cause in upper-extremity injuries was mostly falling (37%). The importance of fall training and limitation of difficulty as well as the number and height of the jumps is discussed. Regular medical examination and improved education of the trainers are demanded.

Accidental Falls↗
PubMed1998

[Quantification of shoulder power in trained and untrained paraplegic wheelchair athletes].

Shoulder complaints are frequently observed to result from the increased stress to the upper extremities of wheelchair users. The cause may be muscle dysbalances of the stressed musculature, whereby the changed situation in the wheelchair during everyday and athletic exercise is important. To demonstrate the different importance of altered shoulder stress in the wheelchair situation and in additional athletic stress, maximum strength in the dominant shoulder was recorded in 14 trained and 13 untrained paraplegics. The goal was to examine the differences between the groups during concentric (60 degrees/s) and eccentric (60 degrees/s) shoulder exercise. Based on the strength/velocity curve, differentiation was also made between the shoulder movements in dependence on various movement velocities. Finally, a comparison was to be made with the test results of untrained and trained, non-paralyzed subjects examined by the same test methods in earlier studies. The results show higher maximum torques in both groups under eccentric stress (p < 0.001), more expressed in trained paraplegics (p < 0.001). In group comparison, there are only slight differences in concentric exercise. The comparison between untrained paraplegics and untrained normal persons (non-paralyzed) show hardly any differences. Trained paraplegics attain values comparable to those of non-paralyzed athletes in eccentric and isometric shoulder exercise. It is concluded, that objective data for determination of the strength situation in the shoulder musculature can be obtained by isokinetic strength measurements in paraplegics. Obviously, eccentric forms of exercise are particularly important. Valuable information can be obtained by determining shoulder strength in dependence on work mode and comparison with non-paralyzed subjects; the information must be interpreted according to the movement.

Adult↗
PubMed1998

Effects of intensive endurance exercise on DNA damage in leucocytes.

OBJECTIVE: It has been shown that highly intensive anaerobic exercise induces DNA damage in leucocytes (LEU). The present study was designed to investigate whether intensive endurance exercise is capable of inducing comparable effects. EXPERIMENTAL DESIGN: A prospective study. PARTICIPANTS: Twelve men (aged 27.3 +/- 4.1 years) who undertook a regular training of different extent (running volume 45 +/- 25 km.week-1) volunteered in the study. INTERVENTIONS: The subjects competed in a half marathon (HM) of 21.1 km, 93.0 +/- 10.4 min. MEASUREMENTS: Blood was taken at rest, 1 and 24 hrs after HM for determination of creatine kinase, neutrophil (PMN), lymphocyte and monocyte counts. DNA damage in LEU at rest and 24 hrs after HM was quantified using the single cell gel-electrophoresis (SCG) assay. RESULTS: PMN increased from 2.81 +/- 0.69 to 13.13 +/- 2.91 1 hrs after HM (p < 0.01) and returned to 3.26 +/- 0.47 10(9) cells.l-1 by 24 hr recovery. DNA migration (image length, IL) reflecting the extent of DNA damage was elevated significantly in 10 of 12 subjects one day after HM. IL rose from 32.7 +/- 2.2 to 40.7 +/- 3.9 microns (p < 0.01). Correlation analysis revealed a relationship between DNA migration 24 hrs after HM and PMN count 1 hr post-exercise (r = 0.67, p < 0.05). CONCLUSIONS: The results confirm the hypothesis that DNA damage in LEU occurs after intensive endurance exercise. We suppose our observation of exercise-induced DNA damage in LEU is affected by reactive oxygen species which are released from PMN. It is quite unclear whether DNA damage in LEU is causal involved in exercise-induced modifications of the immune system.

Adult↗
PubMed1998

[Reis-Buckler dystrophy: therapeutic photo-ablation with the excimer laser].

PURPOSE: Reis-Buckler's corneal dystrophy consist of superficial reticulated opacities with recurring attacks of corneal erosion. Lamellar and penetrating keratoplasties were the traditional surgical means of improving recurrent erosions and vision but the dystrophy recurs following surgery. Phototherapeutic keratectomy (PTK) is now the standard method of managing this anterior corneal disease when intervention is required. MATERIAL AND METHODS: We have treated ten eyes with Reis-Buckler's dystrophy using Excimer laser PTK. RESULTS: All of patients achieved visual improvement (preoperative corrected visual acuity: average 0.3 +/- 0.2 SD, postoperative at one month 0.6 +/- 0.3 SD and 0.7 +/- 0.2 SD at one year. The refractive shift changed from a spherical equivalent of -0.92 D to a postoperative refraction of +1.80 D at one month and +1.65 D at one year.

Adult↗
PubMed1997

Analysis of the PHA granule-associated proteins GA20 and GA11 in Methylobacterium extorquens and Methylobacterium rhodesianum.

Electrophoretic analysis of the proteins bound to poly(3-hydroxybutyric acid), PHB-, granules in Methylobacterium extorquens, M. rhodesianum as well as the PHB-leaky mutants Mu 1 and Mu 11, which were isolated from the latter, resulted in two dominant low-molecular weight proteins, which were referred to as GA11 and GA20. After purification of these proteins antibodies against the GA11 and GA20 protein of M. extorquens were obtained. Both proteins bound to the surface of PHB granules as revealed by immunoelectron microscopy of whole cells of M. extorquens and M. rhodesianum. With cells of the PHB-leaky mutants Mu 1 and Mu 11 no specific labeling was observed. The N-terminal amino acid sequences of the GA11 and the GA20 protein were determined. We found significant homologies between the sequences of the investigated strains. The use of oligonucleotide probes based on the N-terminal sequences of the GA20 protein from M. rhodesianum to identify the corresponding structural genes in various genomic libraries failed.

Acetyl-CoA C-Acyltransferase↗