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Biomedical subjects

C Schmitz

Publications and source records attributed to C Schmitz.

At least 19 recordsLinked to original sources
PubMed2003

Impact of perinatal asphyxia on the GABAergic and locomotor system.

Perinatal asphyxia can cause neuronal loss and depletion of neurotransmitters within the striatum. The striatum plays an important role in motor control, sensorimotor integration and learning. In the present study we investigated whether perinatal asphyxia leads to motor deficits related to striatal damage, and in particular to the loss of GABAergic neurons. Perinatal asphyxia was induced in time-pregnant Wistar rats on the day of delivery by placing the uterus horns, containing the pups, in a 37 degrees C water bath for 20 min. Three motor performance tasks (open field, grip test and walking pattern) were performed at 3 and 6 weeks of age. Antibodies against calbindin and parvalbumin were used to stain GABAergic striatal projection neurons and interneurons, respectively. The motor tests revealed subtle effects of perinatal asphyxia, i.e. small decrease in motor activity. Analysis of the walking pattern revealed an increase in stride width at 6 weeks of age after perinatal asphyxia. Furthermore, a substantial loss of calbindin-immunoreactive (-22%) and parvalbumin-immunoreactive (-43%) cells was found in the striatum following perinatal asphyxia at two months of age. GABA(A) receptor autoradiography revealed no changes in GABA binding activity within the striatum, globus pallidus or substantia nigra. We conclude that perinatal asphyxia resulted in a loss of GABAergic projection neurons and interneurons in the striatum without alteration of GABA(A) receptor affinity. Despite a considerable loss of striatal neurons, only minor deficits in motor performance were found after perinatal asphyxia.

Animals↗
PubMed2003

Specific functions of the motor cortex in reorganizing coordinations during motor training in animals and humans.

The involvement of the motor cortex in learning movements has recently attracted much attention. One aspect of motor learning is the inhibition of innate synergies which interfere with performance of the acquired movement. Various models of operant responses in dogs have demonstrated the critical role of the motor cortex in the reorganization and inhibition of interfering synergies during learning. The role of the motor cortex and corticospinal influences in the formation of new coordinations in humans was studied here in patients with organic lesions of the cerebral circulation involving the internal capsule, using postural coordination and movements in a bimanual unloading response as an example. Formation of the forearm stabilization response was deeply lesioned on the afflicted side. Some degree of impairment was also seen on the ipsilateral side, but it was no different from the level of learning impairment in patients with lesions not involving the internal capsule or in patients with parkinsonism. The existence of specific contralateral influences of the motor cortex and non-specific descending influences on the process of motor learning is proposed.

Aged↗
PubMed2003

Pre-eclampsia and maternal anaemia display reduced apoptosis and opposite invasive phenotypes of extravillous trophoblast.

During pregnancy extravillous trophoblast invades maternal uterine tissues and remodels spiral arteries. Maternal anaemia and early onset pre-eclampsia are associated with perturbed trophoblast biology. We systematically compared numerical density, invasive depth and apoptosis rates of extravillous trophoblast in uterine tissues taken from hysterectomies following Caesarean section after normal pregnancies (n=4) or pregnancies complicated by pre-eclampsia (n=5) or anaemia (n=6). Full thickness sections of the placental bed were studied by immunohistochemistry using anti-active caspase 3, anti-cytokeratin 7, anti-lamin B, M30, Mib-1, anti-PARP, and by the TUNEL assay. In normal pregnancy extravillous trophoblast invaded 2.04+/-0.19 mm (mean+/-SEM ) from the endometrial-myometrial border into the myometrium; in pre-eclampsia 0.67+/-0.14 mm (P< 0.01), and in anaemia 3.84+/-0.21 mm (P< 0.001). The endometrial trophoblast density in normal pregnancy was 2.44+/-0.37 cells per 60,000 microm(3), in pre-eclampsia was 1.04+/-0.15 (P< 0.01), and in anaemia was 3.10+/-0.32. The rate of apoptotic extravillous trophoblast (M30-positive) in the endometrium in normal pregnancy was 7.17+/-1.46 per cent, in pre-eclampsia 4.4+/-0.71, and in anaemia 2.1+/-0.42 (P< 0.01). Maternal anaemia leads to general tissue hypoxia throughout gestation. Increased invasive depth could be explained by hypoxia-stimulated mitosis and decreased apoptosis of extravillous trophoblast. Reduced trophoblast invasion in pre-eclampsia cannot be explained by higher rates of apoptosis.

Adult↗
PubMed2003

Off-Pump versus on-pump coronary artery bypass: can OPCAB reduce neurologic injury?

OBJECTIVE: Coronary artery bypass grafting (CABG) with cardiopulmonary bypass is still the gold standard for surgical myocardial revascularization. Despite advances in techniques and technologies, documented evidence indicates that cardiopulmonary bypass remains the major source of intraoperative brain injury. This study was set up to test whether offpump coronary artery bypass (OPCAB) is superior to CABG regarding postoperative neurologic outcome or neurocognitive function. METHODS: Between January 1999 and June 2001, 251 patients scheduled for coronary revascularization were divided into 2 groups, CABG (control) and OPCAB. All patients underwent an extensive neurologic and neurocognitive battery of tests preoperatively and postoperatively at 48 hours, 7 days, and 3 months following surgery. RESULTS: There were no statistically significant differences between the 2 groups regarding the preoperative or intraoperative data. The means for patient age, number of grafts, and number of central anastomoses were, respectively, 65.4 years (CABG) and 64.6 years (OPCAB), 3.0 (CABG) and 2.2 (OPCAB), and 2.0 (CABG) and 1.2 (OPCAB). The occurrence of stroke was 2.3% (CABG) and 0% (OPCAB). CONCLUSION: Neurologic complications and postoperative neurocognitive dysfunction remain major concerns in coronary artery surgery. Besides the occurrence of stroke, which dramatically reduces the success of the heart operation, the importance of neurocognitive disorders for postoperative quality of life is not yet well defined. OPCAB significantly improves postoperative neurocognitive function, which may in turn improve the postoperative quality of life.

Aged↗
PubMed2002

[Physical-technical principles of extracorporeal shockwave therapy (ESWT)].

Extracorporeal shock waves in orthopaedics are currently applied in the treatment of chronic enthesiopathies such as lateral epicondylitis, plantar heel spur, as well as in calcifying tendinitis of the shoulder or in bony nonunions. Detailed knowledge of physical parameters and properties of shock waves appear to be necessary to determine clinically relevant dose-effect relations and to make shock wave devices, clinical results, and basic science in shock wave therapy more comparable. This study gives an overview of physical parameters and properties in shock wave therapy. Measurement technologies, types of shock wave devices, and mechanisms of shock waves are also described.

Computer Simulation↗
PubMed2002

[Basic research of applying extracorporeal shockwaves on the musculoskeletal system. An assessment of current status].

Detailed knowledge concerning the action of extracorporeal shock waves on the locomotor system as well as concerning possible side effects of extracorporeal shock wave therapy (ESWT) are crucial to optimize the clinical use of ESWT for the treatment of illnesses such as calcific tendinitis of the shoulder, tennis elbow, plantar fasciitis, aseptic pseudarthrosis, and aseptic hip necrosis. This study presents the current knowledge gained from animal experiments, which have yielded important findings, in particular concerning possible side effects of ESWT. Very recent studies have also provided valuable insights into the molecular actions of extracorporeal shock waves on the locomotor system. Further intensified experimental animal research will greatly improve the scientific basis for the clinical use of ESWT in the near future.

Animals↗
PubMed2002

[Micro-coil embolization of a fistula of the circumflex ramus in the coronary sinus. Case report, differential therapy and review of the literature].

A 45 year old male suffered from typical exercise-induced dyspnoea and angina. Crohn's disease treated with glucocorticoids was present for 18 years. Coronary angiography revealed small left anterior descending and right coronary arteries without reference to coronary artery disease, while the main stem and circumflex artery were severely dilated due to a fistula (diameter 5.5 mm) into the coronary sinus with a left/right shunt amounting to 35%. Haemodynamics, significant risk of endocarditis with chronic inflammatory bowel disease and obligatory glucocorticoid treatment were indications for fistula closure. As an alternative to surgical correction, the coronary fistula was totally occluded by antegrade micro-coil embolization. The present report offers a review on differential therapeutic considerations and specific treatment options including novel interventional modalities for coronary fistulas.

Arteriovenous Fistula↗
PubMed2002

Depression: reduced number of granule cells in the hippocampus of female, but not male, rats due to prenatal restraint stress.

It has been hypothesized that decreased neurogenesis in the dentate gyrus may be involved in mediating depressive disorders, which are 1.5-3 times more frequent in women than in men. Additionally, prenatal stress may increase the risk of developing depression in adulthood. However, the interrelations between prenatal stress and the development of depression in adulthood, preferentially in females, are not understood. Here, we subjected pregnant rats to a single 20-min period of restraint stress on day 18 after mating. When the offspring were 75 days of age, the numbers of granule cells and pyramidal cells (area CA1-3) in the hippocampus were analyzed with the optical fractionator. The Cavalieri's principle was applied to analyze the volumes of both granule cell layer and pyramidal cell layer in the hippocampus. Prenatally stressed females, but not males, had reduced numbers of hippocampal granule cells compared to their non-prenatally stressed counterparts. This is the first report of a sex-specific difference concerning the reduction of the number of hippocampal granule cells due to prenatal stress. In humans, prenatal stress may induce cell loss in the granule cells of the hippocampus preferentially in females compared to males, and this may be a sex-specific predisposing factor for the development of depression in adulthood.

Animals↗
PubMed2002

[Submillimeter 3D coronary MR angiography with real-time navigator correction in 107 patients with suspected coronary artery disease].

PURPOSE: To evaluate the clinical value of high-resolution coronary MR angiography (coronary MRA) in a large group of patients with suspected coronary artery disease. METHODS AND MATERIAL: 107 patients with suspected coronary artery disease underwent free-breathing coronary MRA (Intera, 1.5 T, Philips Medical Systems). To compensate for artefacts due to respiratory motion, a right hemidiaphragmatic navigator with real time-time slice correction was used. An ECG-gated, fat-suppressed, 3D segmented-k-space gradient echo sequence (in plane resolution 0.70 x 0.79 mm(2)) was used. Cardiac catheterization with selective coronary angiography was performed in all patients. Visualization of the coronary arteries (CA) was qualitatively assessed using a four-point grading scale. RESULTS: Image quality of grade 1 was achieved in 24 %, grade 2 in 48 %, grade 3 in 24 % and grade in in 4 % of patients. Based on an evaluation of the coronary MRAs of all patients (n = 107) sensitivity and specificity for the detection of stenoses > 60 % in the proximal and middle main coronary arteries were 74 % and 63 %, respectively. In coronary MRAs with good quality [grade 1 and 2, n = 77/107 (72 %)] sensitivity and specificity for the detection of coronary stenoses were 88 % and 91 %, respectively. CONCLUSION: Submillimeter 3D coronary MRA with real-time navigator correction allows high quality imaging of the proximal and middle main coronary arteries with good sensitivity and specificity for detection of stenoses > 50 % in selected patients. However, in about 28 % of patients image quality is severely impaired.

Adult↗
PubMed2002

Influence of extracorporeal shock-wave application on normal bone in an animal model in vivo. Scintigraphy, MRI and histopathology.

There is little information about the effects of extracorporeal shock-wave application (ESWA) on normal bone physiology. We have therefore investigated the effects of ESWA on intact distal rabbit femora in vivo. The animals received 1500 shock-wave pulses each of different energy flux densities (EFD) on either the left or right femur or remained untreated. The effects were studied by bone scintigraphy, MRI and histopathological examination. Ten days after ESWA (0.5 mJ/mm2 and 0.9 mJ/mm2 EFD), local blood flow and bone metabolism were decreased, but were increased 28 days after ESWA (0.9 mJ/mm2). One day after ESWA with 0.9 mJ/mm2 EFD but not with 0.5 mJ/mm2, there were signs of soft-tissue oedema, epiperiosteal fluid and bone-marrow oedema on MRI. In addition, deposits of haemosiderin were found epiperiosteally and within the marrow cavity ten days after ESWA. We conclude that ESWA with both 0.5 mJ/mm2 and 0.9 mJ/mm2 EFD affected the normal bone physiology in the distal rabbit femur. Considerable damaging side-effects were observed with 0.9 mJ/mm2 EFD on periosteal soft tissue and tissue within the bone-marrow cavity.

Animals↗
PubMed2002

Direct aortic cannulation in minimally invasive mitral-valve operations.

The minimally invasive Port-Access (Heartport, Redwood City, CA) approach in mitral-valve operations originally required femoral arterial cannulation, which is considered a disadvantage, especially in patients with peripheral vessel disease. In this study 20 patients were prospectively randomized into 2 groups, to undergo either standard femoral (group A) or direct aortic cannulation (group B). Pre- and postoperative data as well as markers for myocardial damage were assessed. Postoperatively, patients of group B showed lower levels of damage, indicating that direct aortic cannulation might provide better myocardial protection. Furthermore, the direct aortic cannulation technique may eliminate complications associated with the standard femoral artery cannulation.

Aged↗
PubMed2001

ADP-ribose gating of the calcium-permeable LTRPC2 channel revealed by Nudix motif homology.

Free ADP-ribose (ADPR), a product of NAD hydrolysis and a breakdown product of the calcium-release second messenger cyclic ADPR (cADPR), has no defined role as an intracellular signalling molecule in vertebrate systems. Here we show that a 350-amino-acid protein (designated NUDT9) and a homologous domain (NUDT9 homology domain) near the carboxy terminus of the LTRPC2/TrpC7 putative cation channel both function as specific ADPR pyrophosphatases. Whole-cell and single-channel analysis of HEK-293 cells expressing LTRPC2 show that LTRPC2 functions as a calcium-permeable cation channel that is specifically gated by free ADPR. The expression of native LTRPC2 transcripts is detectable in many tissues including the U937 monocyte cell line, in which ADPR induces large cation currents (designated IADPR) that closely match those mediated by recombinant LTRPC2. These results indicate that intracellular ADPR regulates calcium entry into cells that express LTRPC2.

Adenosine Diphosphate Ribose↗
PubMed2001

N-Nitrosomorpholine induced alterations of unscheduled DNA synthesis, mitochondrial DNA synthesis and cell proliferation in different cell types of liver, kidney, and urogenital organs in the rat.

In order to measure rates of unscheduled DNA synthesis (UDS), mitochondrial DNA synthesis, and cell proliferation, i.e. factors relevant in the early phase of carcinogenesis, young rats received by gavage 200 mg/kg N-nitrosomorpholine (NNM) or vehicle (distilled water), and were injected with 3H-thymidine 24 h later. Autoradiographs from liver, kidney, urethra, prostate, seminal vesicle, and ductus deferens were prepared from deparaffinized sections, using a 250-day exposure time. In the liver, UDS was at least doubled in 2n and 4n hepatocytes. Approximately 3% of these hepatocytes exhibited a fourfold increase in UDS. Such strongly labeled cells were only observed in the liver following NNM exposure. With the exception of renal epithelial cells of the proximal tubule, UDS in epithelial cells of bladder, urethra, ductus deferens, seminal vesicle and prostate was decreased in NNM-exposed rats. Mitochondrial DNA synthesis and cell proliferation were significantly increased only in hepatocytes, and were decreased in all other monitored organs in NNM-exposed rats. The strongly increased UDS and more moderately increased mitochondrial DNA synthesis in a subgroup of hepatocytes suggest that possibly some unrepaired damage persists in the DNA of these cells. The latter cells may be the precursors of so-called foci of hepatocellular alteration, which appear later during the process of carcinogenesis. The increased UDS but decreased rate of proliferation in the renal proximal tubule cells might be related to renal carcinogenesis which is observed in NNM-exposed rats after a long latency period.

Animals↗
PubMed2001

On the impact of calcified deposits within the rotator cuff tendons in shoulders of patients with shoulder pain and dysfunction.

We wanted to prove the hypothesis that calcified deposits within the rotator cuff tendons are merely an epiphenomenon of complex morphological alterations in the shoulders of patients with shoulder pain and dysfunction. The shoulders of 92 patients with calcified deposits within the rotator cuff tendons as noted on plain radiographs were investigated by means of magnetic resonance imaging (MRI; mean age of patient 51.1 years), as well as the shoulders of 28 age- and sex-matched patients with similar clinical symptoms but without any signs of such calcified deposits on plain radiographs. The MRI protocol comprised a coronal, oblique, T1-weighted, spin-echo sequence, a T2-weighted, turbo spin-echo sequence, a sagittal, oblique, T2-weighted, turbo spin-echo sequence, and an axial, T1-weighted, spin-echo sequence. Furthermore, a coronal, oblique, short tau-inversion recovery sequence and a gradient echo sequence were used. The results were compared with data from healthy, asymptomatic volunteers as reported in the literature. The MRI investigations showed no substantial differences between patients with or without calcified deposits within the rotator cuff tendons, but distinct differences between such patients and healthy, asymptomatic volunteers. For patients with shoulder pain, shoulder dysfunction, and calcified deposits within the rotator cuff tendons, these calcified deposits are most probably not the main cause of the clinical symptoms. Rather, it seems to be useful to consider the results of MRI investigations whenever planning therapeutic procedures for patients with shoulder pain and dysfunction, irrespective of whether or not there are signs of calcified deposits within the rotator cuff tendons on plain radiographs.

Adult↗
PubMed2001

Extracorporeal shock-wave therapy for chronic lateral tennis elbow--prediction of outcome by imaging.

Today the clinical use of extracorporeal shockwave application (ESWA) for the treatment of lateral tennis elbow is hampered by the lack of results from randomized controlled trials and of predictive parameters of clinical outcome. The present prospective study aimed to provide the latter by means of magnetic resonance imaging (MRI). Twenty-three female and 19 male patients with unilateral chronic tennis elbow of the dominant site were clinically examined before and after repetitive low-energy ESWA. MRI was performed before ESWA to evaluate signal intensity changes or contrast enhancement of the common extensor tendon and the lateral epicondyle. After ESWA (mean follow-up period 18.6 months for all patients), clinical evaluation showed a significantly better mean clinical performance after ESWA than before treatment. Interestingly, male patients showed a significantly better mean clinical performance after ESWA than female patients, and male and female patients differed significantly in the signal intensity of the common extension tendon cross-section and tendon thickening on MRI. For female patients, MRI scans could be applied for predicting a positive clinical outcome of ESWA. This study reports the first indication of predictability of positive clinical outcome of the treatment of chronic lateral tennis elbow by ESWA using imaging prior to treatment. This may serve as an important step towards overcoming the therapeutic nihilism with respect to the non-operative management of this condition recently in the literature.

Adult↗