Myopathy with tubular aggregates and gyrate atrophy of the choroid and retina due to hyperornithinaemia.
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Adult↗
Biomedical subjects
M Mohr
Publications and source records attributed to M Mohr.
Effect of temperature on skeletal muscle energy turnover during dynamic knee-extensor exercise in humans.
The present study examined the effect of elevated temperature on muscle energy turnover during dynamic exercise. Nine male subjects performed 10 min of dynamic knee-extensor exercise at an intensity of 43 W (SD 10) and a frequency of 60 contractions per minute. Exercise was performed under normal (C) and elevated muscle temperature (HT) through passive heating. Thigh oxygen uptake (V(O2)) was determined from measurements of thigh blood flow and femoral arterial-venous differences for oxygen content. Anaerobic energy turnover was estimated from measurements of lactate release as well as muscle lactate accumulation and phosphocreatine utilization based on analysis of muscle biopsies obtained before and after each exercise. At the start of exercise, muscle temperature was 34.5 degrees C (SD 1.7) in C compared with 37.2 degrees C (SD 0.5) during HT (P < 0.05). Thigh V(O2) after 3 min was 0.52 l/min (SD 0.11) in C and 0.63 l/min (SD 0.13) in HT, and at the end of exercise it was 0.60 l/min (SD 0.14) and 0.61 l/min (SD 0.10) in C and HT, respectively (not significant). Total lactate release was the same between the two temperature conditions, as was muscle lactate accumulation and PCr utilization. Total ATP production (aerobic + anaerobic) was the same between each temperature condition [505.0 mmol/kg (SD 107.2) vs. 527.1 mmol/kg (SD 117.6); C and HT, respectively]. In conclusion, within the range of temperatures studied, passively increasing muscle temperature before exercise has no effect on muscle energy turnover during dynamic exercise.
Adenosine Triphosphate↗
[Subthalamic stimulation in a patient with multiple system atrophy: a clinicopathological report].
INTRODUCTION: Efficacy of high frequency subthalamic nucleus (STN) stimulation has been demonstrated in idiopathic Parkinson's disease (IPD). However, since it may be difficult to differentiate IPD from multiple system atrophy with parkinsonian presentation (MSA-P), a few cases of MSA-P has been treated by deep brain stimulation (DBS) and showed no sustained improvement of clinical signs. We report a patient with a clinical misdiagnosed MSA-P, later confirmed by neuropathological study, who was improved by DBS for one year. CASE REPORT: A 63-year-old parkinsonian patient had been treated by levodopa for 6 years with a persistent good response. Over one year he progressively developed disabling fluctuations with severe axial syndrome and vegetative non motor symptoms in off periods. After checking usual contraindications, he was included in surgical procedure protocol (bilateral STN stimulation). During the first year after surgery, the clinical status improved with disappearance of non motor fluctuations, a 45 percent decrease of the OFF UPDRS III score, and a 39 percent reduction of the treatment. However after one year, axial symptoms reappeared with recurrent falls, as well as increasing dysarthry and swallowing difficulties which were only slightly improved by levodopa. He developed severe urinary disorders increased by a prostatic adenoma which led to surgical treatment. During the post operative period, 2 years after DBS, he died suddenly from an unexplained cause. A cerebral autopsy was performed and showed a good position of the two electrodes in the STN. Microscopic studies revealed severe neuronal depletion in the substantia nigra but no Lewy bodies. Immunohistochemical methods demonstrated numerous argyrophilic glial cytoplasmic inclusions positive for alpha-synuclein and ubiquitin in the STN, putamen, globus pallidus, pontine nuclei and cerebellar white matter, significant of MSA. CONCLUSION: This case shows that DBS can improve parkinsonian signs in MSA-P with persistent dopa sensitivity. However, probably because of striatal degeneration progression, this improvement is time limited and STN DBS cannot be recommended in MSA.
Adenoma↗
[Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) in patients with solid organ transplantation: a clinical, neurophysiological and neuropathological study of 4 cases].
INTRODUCTION: Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) rarely develops in patients with solid organ transplantation. PATIENTS AND METHOD: We describe the clinical, biological, electrophysiological and neuropathological features of 4 patients with solid organ transplantation who developed CIDP. Two patients had liver transplantation, one had kidney transplantation and one had lung transplantation. RESULTS: All 4 patients developed in the months following transplantation a syndrome that fulfilled criteria for definite CIDP. All patients had immunosuppressive therapy, with ciclosporin + prednisolone in 2 cases, tacrolimus in 1 case and azathioprine + prednisolone + ciclosporin in one case. One patient had chronic HCV and HBV infection. Treatment with intravenous immune globulin (IVIG) and/or a change in immunosuppressive therapy improved the neuropathy in all cases. CONCLUSION: CIDP is a rare and potentially treatable condition that should be considered in all patients with solid organ transplantation who develop a rapidly disabling sensorimotor polyneuropathy.
Humans↗
A semi-empirical molecular orbital scheme to study electron transfer in iron-sulphur proteins.
We describe the use of the semi-empirical molecular orbital method PM3 (parametric method 3) to study the electronic structure of iron-sulphur proteins. We first develop appropriate parameters to describe models of the redox site of rubredoxins, followed by some preliminary calculations of multinuclear iron systems of relevance to hydrogenases.
Electrons↗
[Advance directives in the prehospital setting -- emergency physicians' attitudes].
OBJECTIVE: The German physician based emergency medical system (EMS) might confront physicians with advance directives in the field. A multi-question survey was used to evaluate emergency physicians' experience with advance directives in the prehospital setting and to assess their attitudes towards forms and statements of advance directives. METHODS: A questionnaire was mailed to the members of the Association of Emergency Physicians of Northern Germany ("AGNN"), an interest group of emergency physicians, in 2001. RESULTS: 511 emergency physicians (50,4 % of the AGNN members) filled in the questionnaire completely and sent it back for evaluation. 75 % of the participants were working as emergency physicians at present, 72 % had emergency experiences of more than 5 years. One third had previously dealt with advance directives in the prehospital setting. 77 % of these physicians thought advance directives generally helpful. Nevertheless 88 % based their management on the context of the individual circumstances (e. g. emergency conditions, underlying diseases, expected prognosis), only 7 % said they would always exactly follow the statements of the directive. In the view of the emergency physicians the advance directive should contain information on cardiopulmonary resuscitation (CPR: 88 %), intensive care-treatment (75 %) and preclinical emergency treatment (55 %). Information on underlying diseases (87 %) and a legal substitute (84 %) should be contained as well. As formal requirements, 47 % of the physicians wanted the family doctor to be involved, 49 % desired a notary authenticity confirmation, additionally or solely. Pragmatically, the advance directive should be kept with the personal documents (84 %). A regular reconfirmation was deemed necessary (twice to once a year: 64 %). The current legal situation was regarded as unclear by 81 % of the emergency physicians, 85 % favored a unique, officially authorized type of directive. CONCLUSION: The high number of returned questionnaires shows the importance of the topic "advance directives" for emergency physicians. Despite some practical and legal problems, a big majority of the experienced emergency physicians in this survey thought the advance directives in the prehospital setting to be helpful. A clear statement on resuscitation as well as simplification of the many existing types of directives are the most essential requirements demanded by the emergency physicians. A solution could be the creation of an extra "emergency advance directive".
Attitude of Health Personnel↗
Elevations in core and muscle temperature impairs repeated sprint performance.
AIM: The present study investigated the effects of hyperthermia on intermittent exercise and repeated sprint performance. METHODS: Seven men completed 40 min of intermittent cycling comprising of 15 s exercise (306 +/- 22 W) and 15 s rest periods (0 W) followed by 5 x 15 s maximal sprints on a cycle ergometer in normal (approximately 20 degrees C, control) and hot (40 degrees C, hyperthermia) environments. RESULTS: Completion of the intermittent protocol in the heat elevated core and muscle temperatures (39.5 +/- 0.2 degrees C; 40.2 +/- 0.4 degrees C), heart rate (178 +/- 11 beats min(-1)), rating of perceived exertion (RPE) (18 +/- 1) and noradrenaline (38.9 +/- 13.2 micromol l(-1)) (all P < 0.05). During the first sprint (n = 6), both peak and mean power output were similar across the environmental conditions. However, mean power over the last four sprints declined to a larger extent during hyperthermia compared with the control trial (P < 0.05). Consequently, average mean power output during the five sprints was lower in hyperthermia (558.0 +/- 146.9 W) compared with control (617.5 +/- 122.6 W; P < 0.05). Power output during the repeated sprints was reduced by hyperthermia despite an elevated muscle temperature that should promote sprint performance. Venous plasma potassium concentrations (H; 5.3 +/- 0.8 mmol l(-1) vs. C; 6.3 +/- 1.0 mmol l(-1), P = 0.06) and muscle lactate levels (H; 76.6 +/- 24.3 mmol kg(-1) dry weight vs. C; 108.8 +/- 20.1 mmol kg(-1) dry weight) were lower following the hyperthermic sprints compared to control. CONCLUSION: Although an elevated muscle temperature is expected to promote sprint performance, power output during the repeated sprints was reduced by hyperthermia. The impaired performance does not seem to relate to the accumulation of recognized metabolic fatigue agents and we, therefore, suggest that it may relate to the influence of high core temperature on the function of the central nervous system.
Adult↗
New method for time-resolved diesel engine exhaust particle mass measurement.
The Dekati mass monitor (DMM; Dekati Ltd., Finland), a relatively new real-time mass measurement instrument, was investigated in this project. In contrast to the existing gravimetric filter method also used as a standard for regulation purposes, this instrument provides second-by-second data on mass concentration in the engine exhaust gas. The principle of the DMM is based on particle charging, inertial and electrical size classification, and electrical detection of aerosol particles. This study focuses on the instrument's practical performance. Details on calibration and the theory of operation will be published elsewhere. The exhaust emissions of two heavy-duty engines complying with the Euro III emission standard were measured on a dynamic engine test bench. We looked atthe particle number and mass emissions of the engines in different transient test cycles and steady-state conditions. The ability to follow transient test cycles and the response times of the DMM were investigated. The aerosol mass concentration measured by the DMM was compared with the mass concentration obtained by the standard gravimetric filter method with Teflon-coated glass fiber filters. The total mass concentration (integral over the whole cycle) measured by the DMM is about 20% higher than that measured by the standard gravimetric filter method. The total mass concentration from the DMM was also compared with the volume concentration calculated from the electrical low-pressure impactor (ELPI) measurements. Correlations were made with other particle measuring systems. The DMM correlates very well with the particulate mass (R2 = 0.95) and exhibits good linearity and repeatability. The response time to a well-defined change in exhaust concentration was observed to be fast and stable. The DMM was able to follow transient test cycles and provides good results on a second-by-second basis. The instrument used in this study was still under development, and there is therefore no complete scientific background reference for the DMM. This study therefore focuses more on the measurements than on the scientific background. The measurements have shown thatthe DMM is an adequate instrument for measuring the mass concentration of engine exhaust, with results comparable to those from the standard gravimetric filter method. In addition, the DMM provides real-time second-by-second data of the mass concentration during transient test cycles.
Environmental Monitoring↗
Finite helical axes of motion are a useful tool to describe the three-dimensional in vitro kinematics of the intact, injured and stabilised spine.
The finite helical-axes method can be used to describe the three-dimensional in vitro kinematics of the spine. However, this method still suffers from large stochastic calculation errors and poorly conceived visualisation techniques. The aim of the present study, therefore, was to improve the currently used finite helical axes description, by use of a less error-prone calculation algorithm and a new visualisation technique, and to apply this improved method to the study of the three-dimensional in vitro kinematics of the spine. Three-dimensional, continuous motion data of spinal motion segments were used to calculate the position and orientation of the finite helical axes (FHAs). The axes were then projected on plane antero-posterior, lateral and axial radiographs in order to depict the relation to the anatomy of each individual specimen. A hinge joint was used to estimate the measurement error of data collection and axes calculation. In an exemplary in vitro experiment, this method was used to demonstrate the ability of a prosthetic disc nucleus to restore the three-dimensional motion pattern of lumbar motion segments. In the validation experiment with the hinge joint, the calculated FHAs were lying within +/-2.5 mm of the actual joint axis and were inclined relative to this axis at up to +/-1.5 degrees . In the exemplary in vitro experiment, the position and orientation of the FHAs of the intact specimens were subject to large inter-individual differences in all loading directions. Nucleotomy of the lumbar segments caused the axes to spread out, indicating complex coupled motions. The implantation of the prosthetic disc nucleus, for the most part, more than reversed this effect: the axes became oriented almost parallel to each other. The experiments showed that the present improved description of finite helical axes is a valid and useful tool to characterise the three-dimensional in vitro kinematics of the intact, injured and stabilised spine. The main advantage of this new method is the comprehensive visualisation of joint function with respect to the individual anatomy.
Algorithms↗
Muscle temperature and sprint performance during soccer matches--beneficial effect of re-warm-up at half-time.
The relationship between quadriceps muscle temperature (T(m)) and sprint performance was evaluated during soccer matches in 25 competitive players. In one game, T(m) was determined frequently (n=9). In another game, eight players performed low-intensity activities at half-time (re-warm-up, (RW), whereas another eight players recovered passively (CON). T(m) was 36.0+/-0.2 degrees C at rest and increased (P<0.05) to 39.4+/-0.2 degrees C before the game and remained unaltered during the first half. At half-time, T(m) decreased (P<0.05) to 37.4+/-0.2 degrees C, but increased (P<0.05) to 39.2+/- degrees C during the second half. In CON and RW, T(m) and core temperature (T(c)) were similar before and after the first half, but 2.1+/-0.1 and 0.9+/-0.1 degrees C higher (P<0.05), respectively, in RW prior to the second half. At the onset of the second half, the sprint performance was reduced (P<0.05) by 2.4% in CON, but unchanged in RW. The decrease in T(m) was correlated to the decrease in performance (r=0.60, P<0.05, n=16). This study demonstrates that in soccer, the decline in T(m) and T(c) during half-time is associated with a lowered sprint capacity at the onset of the second half, whereas sprint performance is maintained when low-intensity activities preserve muscle temperature.
Body Temperature↗
Comparing iterative solvers for linear systems associated with the finite difference discretisation of the forward problem in electro-encephalographic source analysis.
Model-based reconstruction of electrical brain activity from electro-encephalographic measurements is of growing importance in neurology and neurosurgery. Algorithms for this task involve the solution of a 3D Poisson problem on a realistic head geometry obtained from medical imaging. In the model, several compartments with different conductivities have to be distinguished, leading to a problem with jumping coefficients. Furthermore, the Poisson problem needs to be solved repeatedly for different source contributions. Thus efficient solvers for this subtask are required. Experience with different iterative solvers is reported, i.e. successive over-relaxation, (preconditioned) conjugate gradients and algebraic multigrid, for a discretisation based on cell-centred finite differences. It was found that: first, the multigrid-based solver performed the task 1.8-3.5 times faster, depending on the platform, than the second-best contender; secondly, there was no need to introduce a reference potential that forced a unique solution; and, thirdly, neither the grid- nor matrix-based implementation of the solvers consistently gave a smaller run time.
Algorithms↗
[To resuscitate or not? The emergency physician's decision in the prehospital setting].
OBJECTIVE: To identify factors affecting the decision to withhold resuscitative attempts or to terminate cardiopulmonary resuscitation (CPR) in the prehospital setting. METHODS: In a physician-based emergency medical system (EMS) standardised interviews with the emergency physicians were performed within 24 hours after unsuccessful or withheld CPR-efforts. RESULTS: Over a period of one year 170 prehospital cardiac arrests were evaluated. 47 patients (28 %) were declared dead on arrival by the emergency physician. The decision to withhold CPR was based on obvious clinical signs of death (32 patients) or the diagnosis of cardiac arrest due to severe trauma (8 patients). In 4 cases the terminal state of a fatal illness was the emergency physician's criterion not to initiate resuscitative efforts. In 3 patients an extended response time (more than 10 minutes) was mentioned, in combination with a primary rhythm of either asystole or electromechanical dissociation and additional information given by the family doctor. In 123 patients CPR was attempted. In 72 cases (59 %) resuscitative efforts were terminated as no return and stabilisation of spontaneous circulation was achieved. In 58 patients the decision to stop CPR was based on the evidence of cardiac death. Additional criteria for the termination of the resuscitation attempt were the duration of CPR, an extended response time, pre-existing diseases, age, pupillary status, missing brain stem reflexes, the reason of cardiac arrest, information given by the family or the family doctor and secondarily evolving signs of death. In 14 patients the emergency physicians reported that their decision to terminate CPR was primarily based on these co-factors, the evidence of cardiac death was not explicitly mentioned in these cases. CONCLUSION: In the pre-hospital setting the decision to withhold or to withdraw CPR is mostly based on reliable criteria such as obvious clinical signs of death, fatal trauma or evidence of cardiac death. Nevertheless, in a small but considerable number of cases exceptions to this rule are made by emergency physicians.
Adolescent↗
Linkage to 18qter differentiates two clinically overlapping syndromes: congenital cataracts-facial dysmorphism-neuropathy (CCFDN) syndrome and Marinesco-Sjögren syndrome.
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Abnormalities, Multiple↗
Early tandem high-dose ifosfamide, carboplatin, etoposide therapy with stem cell rescue for small-cell lung cancer: brief report on the results of a phase-I/II trial.
OBJECTIVE: High-dose therapy (HDT) for small-cell lung cancer is experimental. Late intensification HDT for chemosensitive disease can increase the number and quality of remissions and prolong relapse-free survival, but has not yet shown impact on overall survival. This is possibly due to resistant residual disease. To overcome the development of resistance, we have tested early intensification tandem HDT. METHODS: We performed a phase-I/II trial using 1 conventional cycle of ifosfamide, carboplatin, etoposide (ICE) plus granulocyte colony-stimulating factor for stem cell recruitment followed by 2 cycles of high-dose ICE with rescue by CD34+ cell-enriched peripheral blood mononuclear cells. Dose escalation was performed for the 2 high-dose ICE cycles. Radiotherapy for limited disease was according to standard protocols. RESULTS: 17 patients were entered: 2 female patients; 15 male patients; median age 53 (range 36-65) years; 2 patients with limited disease, and 15 patients with extensive disease. We treated 4 patients at dose level 1, 11 patients at level 2, and 2 patients at level 3. The maximum tolerable dose was at level 2 with neuropathy being dose-limiting. Overall, toxicity was < or = grade 2 for all patients up to dose level 2 with hematotoxicity being grade 4 for all patients. There were 15 partial remissions (88%), 1 no change (6%), and 1 progressive disease (6%). Median time to progression was 7.9 months. Overall survival was 12.9 months (median). CONCLUSIONS: Early intensification with this protocol is feasible. Although a comparatively good response rate and median time to progression have been observed in this group dominated by patients with extensive disease, overall survival is short and no substantial long-term survival was found.
Adult↗
Comparison of macroscopic models of excitation and force propagation in the heart.
Computer aided simulations of the heart provide knowledge of phenomena, which are commonly neither visible nor measurable with current techniques. This knowledge can be applied e.g. in cardiologic diagnosis and therapy. A variety of models was created to reconstruct cardiac processes, e.g. electrical propagation and force development. In this work different macroscopic models were compared, i.e. models based on excitation-diffusion equations and cellular automata. The comparison was carried out concerning reconstruct-ability of cardiac phenomena, mathematical and biophysical foundation as well as computational expense. Particularly, the reconstruct-ability of electromechanic feedback mechanisms was examined. Perspectives for further developments and improvements of models were given.
Animals↗
[Prion diseases].
Creutzfeldt-Jakob disease, kuru, Gerstmann Sträussler Scheinker syndrome and fatal familial insomnia in humans, as well as scrapie and bovine spongiform encephalopathy, in animals, are fatal disorders of the central nervous system that are part of the group of transmissible spongiform encephalopathies, (TSE) or prion diseases. Neuronal intracellular spongiosis and the accumulation of abnormal, protease resistant prion protein in the nervous central system characterize TSE. The conformational change of a host protein, prion protein, into a pathological isoform is the key pathogenetic event in TSE. Despite their relative rarity, prion diseases have a great impact on the scientific community and society in general. There are two major reasons: first, the heretical hypothesis of a disease transmitted by an "infectious protein" in the absence of nucleic acid, the basis of the conformational transmissibility concept; second, the panic originated from the appearance of new variant Creutzfeldt-Jakob disease and the evidence linking it to the exposure of humans to bovine spongiform encephalopathy via food contaminated by affected bovine tissue. Novel therapeutic approaches are examined.
Brain↗
Autologous peripheral blood stem cell transplantation and anti-B-cell directed immunotherapy for refractory auto-immune haemolytic anaemia.
UNLABELLED: We report the clinical course of a 6.5-year-old boy with refractory auto-immune haemolytic anaemia. Due to failure of conventional immunosuppressive therapy, an autologous peripheral blood stem cell transplantation was performed. The conditioning regimen consisted of cyclophosphamide and anti-thymocyte globulin. The patient was reinfused with 2.6 x 10(6) CD34 positive selected, B- and T-cell-depleted peripheral blood stem cells per kg body weight. He showed a partial response with a reduced demand for red blood cell transfusions. However, due to persistence of the haemolytic process he was started on rituximab therapy on day +40 post-transplant. Following two doses of rituximab, the patient improved rapidly and developed a sustained complete response. After 10 months, haemolysis recurred and responded again to rituximab therapy without the necessity for red blood cell transfusions. 15 months after initial antibody treatment, however, the patient developed a second relapse which was now refractory to rituximab therapy although CD20+ B-lymphocytes were cleared from the peripheral blood. CONCLUSION: Our case report suggests that rituximab and autologous peripheral blood stem cell transplantation are important though not curative elements in the treatment of patients with severe auto-immune haemolytic anaemia who are refractory to conventional immunosuppressive therapy.
Anemia, Hemolytic, Autoimmune↗
Kinetics of standardized large volume leukapheresis (LVL) in patients do not show a recruitment phenomenon of peripheral blood progenitor cells (PBPC).
Although several studies have demonstrated the efficacy of large volume leukapheresis (LVL) to yield high numbers of peripheral blood progenitor cells (PBPC), the mechanisms of stem cell release into circulation and the postulated phenomenon of PBPC recruitment during apheresis have not been investigated in detail. Therefore, we analyzed the kinetics of stem cell enrichment in a total of 34 standardized LVL for patients with hematologic malignancies (lymphoma, multiple myeloma) and solid tumors (breast cancer, rhabdomyosarcoma). LVL was started 2 h after administration of G-CSF processing six times the patient's blood volume. Cells were sequentially collected into six bags and the numbers of leukocytes, mononuclear cells (MNC), CD34+ cells and colony-forming cells (CFU-GM) in each collection bag were analyzed. The numbers of PBPC collected demonstrated a continuous decrease starting after an early maximum during the second processed blood volume (P = 0.001). Interestingly, these kinetics of decreasing stem cell yields during LVL were similar for both entities of patients with hematologic malignancies as well as for both groups of patients with solid tumors. In summary, a recruitment phenomenon, defined as a time-dependent and LVL-induced increase of PBPC, could not be demonstrated in any of the diseases investigated.
Adolescent↗