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Biomedical subjects

R Schröder

Publications and source records attributed to R Schröder.

At least 19 recordsLinked to original sources
PubMed2004

[Optimization of microsurgical operation technique to insert auditory brainstem implants, taking into account the results of a morphometric study].

STATE OF THE ART: The surgical placement of auditory brainstem implants to stimulate the cochlear nuclear region in patients with acquired bilateral retrocochlear deafness allows limited restitution of hearing. However, there have been few studies on the topographical relations in the target region, particularly the floor of the IVth ventricle. TOPIC OF THE STUDY: Is it possible to obtain more precise anatomical data in order to improve the surgical approaches and techniques for the placement of auditory brainstem implants? AIMS. To obtain a more precise topo- anatomical orientation in the target region for microsurgical lateral and midline approaches or a stereotactic operative strategy. METHODS AND RESULTS: Landmarks for the placement of an auditory brainstem implant via the IVth ventricle were examined and measured in a series of formalin-fixed human brainstems ( n=28). These data, and knowledge of their variability, allow a more precise surgical lateral approach. It is essential to precisely localise the target region, as it can only be partly discerned under the microscope during an operation. For this reason, to date its precise localisation has been determined only electrophysiologically. CONCLUSION: Exact target localisation improves safety. From an anatomical point of view the midline approach gives the chance to enlarge the indication spectrum for an implant. The anatomical data obtained here could also be integrated into a stereotactic surgical strategy.

Adult↗
PubMed2004

[Isaacs' syndrome. Diagnosis and differential diagnosis of neuromyotonia].

Neuromyotonia is a clinical and electrophysiological syndrome of spontaneous muscle fiber activity due to hyperexcitability of peripheral nerve origin causing generalised, visible myokymia and muscular cramps. Electromyography shows abnormal doublet and triplet discharges of high intraburst frequency as well as myokymic and neuromyotonic discharges. Fasciculations and fibrillation potentials are common. Most commonly, neuromyotonia is an acquired immune-mediated disorder (Isaacs' syndrome) showing elevated antibody levels against presynaptic, voltage-gated, potassium channels. Some of these patients have additional autonomic (hyperhidrosis) and/or CNS symptoms similar to those from limbic encephalitis (referred to then as Morvan's syndrome). We report on a patient with Isaacs' syndrome and discuss the clinical and electrophysiological features, pathophysiology, diagnosis, and differential diagnosis of diseases with peripheral nerve hyperexcitability.

Diagnosis, Differential↗
PubMed2004

[Prediction of outcome in ST elevation myocardial infarction by the extent of ST segment deviation recovery. Which method is best?].

UNLABELLED: Simple and rapid measures are needed for timely assessment of the quality of reperfusion therapy early after fibrinolysis in acute STEMI. Sum ST segment elevation resolution (sum STR) categorized into the three groups of low risk (complete ST resolution), medium risk (partial ST resolution), and high risk (no ST resolution) has become an established method to predict infarct size, left ventricular function, epicardial vessel patency, and mortality. However, measurement of the sum of ST elevation from all leads of repeated ECG's is time-consuming. For routine practice more simple measures are needed. This report summarizes recent findings on direct comparisons between different modes of evaluation of ST segment deviation recovery employed for risk stratification in large-scale mortality trials. With respect to predictive accuracy combined with simplicity, two methods were superior to the conventional model of sum STR: 1) ST segment deviation resolution in only the one ECG lead showing the maximal deviation (single lead STR), and 2) the existing ST segment deviation in the single ECG lead of maximum deviation present 90 or 180 min after start of fibrinolysis (max STE). In multivariate analyses the ST segment deviation recovery models including sum STR were significant independent predictors of short- and long-term mortality. In receiver-operating characteristic (ROC) curves for predicting mortality the analysis of single lead STR and max STE performed better than sum STR. After categorization into risk groups patients are best classified by max STE. With an ECG recorded at 90 min in 2719 patients, the proportion of patients of sum STR, single lead STR, and max STE were 40, 34, and 43% in the low risk groups, and 24, 31, and 25% in the high risk groups. Cardiac mortality rates at 30 days were 2.0, 1.2, and 1.0% in low risk versus 9.6, 10.3, and 12.8% in the high risk groups, respectively. Long-term mortality with a followup of 5 years was best predicted by max STE risk groups. CONCLUSION: Single lead STR and max STE are very simple, inexpensive, non-invasive, and highly reliable measures which provide very strong early prognostic information. The relationship between degree of ST segment deviation recovery and subsequent mortality is remarkably consistent. Both methods perform better than sum STR in predicting mortality. They can be used for very early risk stratification and can form a basis for an individual treatment of patients after fibrinolysis for STEMI within 6 hours of symptom onset. Of the two methods max STE is even simpler to use and has better accuracy in predicting outcome.

Aged↗
PubMed2004

Potential risk factors for bovine Neospora caninum infection in Germany are not under the control of the farmers.

In the German state of Rhineland-Palatinate, herds were identified that were likely to have a Neospora caninum sero-prevalence > or = 10% by using a bulk milk ELISA. Individual herd data were obtained by a questionnaire. Univariate logistic regression showed that bulk milk positive farms had a significantly higher chance to report an increased abortion rate than negative farms (P(Wald)<0.1). The chance to have a bulk milk positive herd increased with the minimum number of years a farm had reported an increased abortion rate (P(Wald)<0.1). Questionnaire data, population and dog density as well as climatic data specific for the farm localization were used to identify potential risk factors for a herd to have acquired N. caninum infections. Within an optimized multiple logistic regression model 'Number of farm dogs', 'Herd size', and factors related to the municipality the farm was localized, i.e. 'Mean temperature in July', and 'Dog density' were significant risk factors (P(Wald)<0.1). The present study underlines the role farm dogs have in the epidemiology of neosporosis. In addition, it suggests that the risk a herd has to acquire N. caninum infections is also associated with factors related to the farm location, i.e. factors that are largely out of the control of farmers.

Abortion, Veterinary↗
PubMed2003

[Macrophagic myofasciitis: inflammatory, vaccination-associated muscular disease].

HISTORY AND ADMISSION FINDINGS: A 67-year-old man presented with a 6-week history of slowly progressive muscle pain and generalized muscular weakness. Neurological examination showed symmetrical proximal weakness (MRC grade 4/5). INVESTIGATIONS: Laboratory tests revealed an elevated CK level of 124 U/l (normal < 80). Needle EMG showed pathological spontaneous activity in proximal muscle groups. A diagnostic muscle biopsy taken from the left deltoid muscle revealed a characteristic infiltrate of PAS-positive and acid phosphatase-positive macrophages. Electron microscopic analysis of muscle tissue failed to demonstrate aluminium hydroxide inclusion. Serological analysis excluded antibodies against HAV and HBV but was compatible with a previous tetanus vaccination (antibody titre of 2.3 IE/ml). TREATMENT: A 2-year treatment with steroids and azathioprine led to complete recovery of muscle strength without relapse after discontinuing the immunosuppression. CONCLUSION: Macrophagic myofasciitis (MMF) is a rare inflammatory muscle disorder characterized by a characteristic infiltration of muscle tissue by PAS-positive macrophages, which is caused by pathological persistence of vaccine-derived aluminium hydroxide. The diagnosis can only be established by an open muscle biopsy from the muscle that was used for intramuscular vaccination.

Adrenal Cortex Hormones↗
PubMed2003

Filamin C accumulation is a strong but nonspecific immunohistochemical marker of core formation in muscle.

Filamin C is the muscle isoform of a group of large actin-crosslinking proteins. On the one hand, filamin C is associated with the Z-disk of the myofibrillar apparatus and binds to myotilin; on the other hand, it interacts with the sarcoglycan complex at the sarcolemma. Filamin C may be involved in reorganizing the cytoskeleton in response to signalling events and in muscle it may, in addition, fulfill structural functions at the Z-disk. An examination of biopsies from patients with multi-minicore myopathy, central core myopathy and neurogenic target fibers with core-like target formations (TF) revealed strong reactivity of all the cores and target formations with two different anti-filamin C antibodies. In all three conditions, the immunoreactivity in the cores for filamin C was considerably stronger than that for desmin. Only for alphaB-crystallin were comparable levels of immunoreactivity detected. There was no difference in intensity for filamin C between the three pathological conditions. Thus, filamin C along with alphaB-crystallin is a strong and robust, but nonspecific marker of core formation. The reason why filamin C accumulates in cores is unclear at present, but we postulate that it may be critically involved in the chain of events eventually leading to myofibrillar degeneration.

Biomarkers↗
PubMed2003

Beyond LGMD1A: myotilin is a component of central core lesions and nemaline rods.

Myotilin is a Z-disc protein that binds alpha-actinin, gamma-filamin and F-actin. The essential role of myotilin in skeletal muscle is highlighted by the recent observation that autosomal dominant limb girdle muscular dystrophy type 1A is caused by mutations in the human myotilin gene. We studied the expression and subcellular distribution of myotilin in nemaline myopathy, central core disease, centronuclear myopathy, and myopathies with tubular aggregates. A prominent myotilin immunostaining of nemaline rods and core lesions was detected in all ten cases of nemaline myopathy and five cases of central core disease. This renders myotilin a sensitive, though non-specific marker for these structural lesions. Western blot analysis did not indicate an increased myotilin expression in nemaline myopathy muscle. However, the analysis indicated upregulation of a 75 kDa immunoreactive band, very weak in control muscle but previously detected in limb girdle muscular dystrophy 1A samples. Our findings indicate that myotilin is a core structural molecule in nemaline rods and central core lesions and suggest modification of myotilin in nemaline myopathy, and further support the notion that myotilin may have a key role in the dynamic molecular events mediating myofibril assembly in normal and diseased human skeletal muscle.

Antibody Specificity↗
PubMed2003

Influence of TachoComb in comparison to local hemostyptic agents on epidural fibrosis in a rat laminectomy model.

This animal experimental study was designed to examine the effects of TachoComb, a fixed combination of collagen with tissue adhesive, as an interposition membrane on the development of spinal epidural fibrosis in comparison to other hemostyptic materials. In 10 Wistar rats, four laminectomies were performed at lumbar and sacral vertebrae. Alternately, a piece of TachoComb, Spongostan, or Tabotamp was placed into each laminectomy site. One laminectomy site served as an empty control (n = 10). 8 weeks later, the animals were sacrificed, and the spinal column including surrounding muscle tissue was removed en bloc from each rat and fixed in formaldehyde. After decalcification and staining the specimens were graded by a neuropathologist in a blindfold test for severity of epidural fibrosis as "light-moderate" or "marked". Epidural scarring of variable density was seen in all laminectomy sites. Light epidural fibrosis, without any adhesion to dura, as only noted in cases after application of TachoComb (n = 4/10) and Spongostan (n = 1/10). All other slices showed marked epidural fibrosis with dura adherence regardless of the implanted material. Statistical analysis revealed significantly lower epidural fibrosis after application of TachoComb compared to all other groups (p < 0.05). In this series, TachoComb is more effective in reducing the epidural fibrosis than Spongostan, and Tabotamp. However, complete prevention of scar tissue formation was not achieved.

Animals↗
PubMed2002

p38-avidity-ELISA: examination of herds experiencing epidemic or endemic Neospora caninum-associated bovine abortion.

An enzyme-linked immunosorbent assay (ELISA) was established to measure the avidity of bovine IgG directed against p38, a surface antigen (NCSRS2) of Neospora caninum tachyzoites. In the sera of dams intravenously infected with N. caninum NC-1, the p38-specific avidity increased from initially below 40% up to avidity indices between 50 and 80% after days 23 and 91 p.i. The p38-avidity-ELISA was used to examine various herds that had experienced endemic and epidemic N. caninum-associated bovine abortions. In herds with endemic abortion, generally high avidity indices of N. caninum-specific IgG were detected. This finding and the observation of an association between the seropositivity of dams and that of their offspring suggested a predominantly vertical transmission of the parasite among the animals of these herds, thus indicating chronic infection of these cattle. In contrast, for herds experiencing epidemic abortion: (i) an association regarding seropositivity of dams and their daughters could not be shown and (ii) a generally low avidity of p38-specific IgG in the sera from aborting dams was determined. This indicates recent postnatal transmission of N. caninum in these herds. A linear regression model explaining the avidity of p38-specific IgG was significantly influenced by the time span between sampling and the occurrence of the first abortion of the epidemic in herds with an N. caninum-associated abortion storm. Another factor significantly contributing to the model was the proportion of dams at risk that had aborted in the herds (i.e. the severity of the abortion epidemic). A possible explanation for this observation is that herds experiencing heavy abortion are sampled earlier after the onset of the epidemic than others that have a less severe abortion storm.

Abortion, Veterinary↗
PubMed2002

[Multifocal motor neuropathy: diagnosis and differential diagnosis].

Multifocal motor neuropathy (MMN) is an acquired immune mediated motor neuropathy with characteristic clinical and neurographic features.Clinically, MMN is characterized by progressive, predominantly distal and asymmetrical limb weakness. Neurographic recordings demonstrate features of multifocal demyelination with or without conduction block. Sensory nerves are not affected. Due to strict diagnostic criteria,MMN may be underdiagnosed in patients with motor neuropathies. Since intravenous immunglobulins are an efficient therapy for MMN,clinical and electrophysiological differentiation from other neuromuscular disorders is mandatory to prevent progressive impairment of motor function. We present a patient with MMN and review the clinical, electrophysiological, and histological features. In addition,pathogenesis, differential diagnosis and treatment of MMN are discussed.

Adult↗
PubMed2002

The spectrum of pathology in central core disease.

Central core disease is a congenital myopathy with muscle weakness defined pathologically by the presence of extensive areas in muscle fibres that are devoid of oxidative enzyme activity. The gene responsible has been shown to be the ryanodine receptor 1 on chromosome 19q13 and mutations have now been identified in several patients. Some cases with the morphological defect remain molecularly undefined, particularly those studied before molecular studies were available. We have studied three families with congenital onset, each with a dominantly inherited mutation in a C-terminal exon of the ryanodine receptor 1. They illustrate the spectrum of pathology that can be observed in patients with the myopathic features of central core disease. We show that extensive fibrosis and fat may be present, type 1 fibre uniformity may occur in the absence of cores; cores may be central or peripheral, single or multiple; and that an appearance of multiple focal minicores might cause a diagnostic pathological dilemma. In addition, we show the value of immunocytochemistry in identifying cores, in particular the use of antibodies to desmin and gamma-filamin.

Adult↗
PubMed2002

[Comparison between endorectal MRI (EMRTI) and endorectal sonography (ES) after surgery or therapy for rectal tumors to exclude recurrent or residual tumor].

PURPOSE: This study was designed to evaluate the accuracy and limitations for staging of contrast-enhanced endorectal MR imaging comparing with transrectal US for restaging of rectal lesions after surgery or after therapeutic radiation. Both methods were correlated with histologic findings. METHOD/MATERIALS: The efficacy of these both methods was evaluated in 30 patients with supposed residual or recurrent rectal neoplasms. Contrast enhanced (bolus injection of 0.1 mmol/kg b.w. Gd-DTPA) endorectal MR imaging was performed using a 1.5 Tesla Magnetom. In addition endosonography (7.5 x or 10-MHz transducer) was used. RESULTS: In 8 patients with rectal adenoma after electro-laser resection, 8 patients with rectal carcinoma stage pT1 after transanal resection, 8 patients with rectal carcinoma stage pT2 and 6 patients with rectal carcinoma stage pT3 after regional hyperthermia with radiochemo-therapy, the following results were obtained during the postsurgical or posttherapeutical follow-up with respect to histopathological evaluation: exact staging in 86.6 % with EMRI and 63.3 % in ES, overstaging in 8 % (EMRI) and 23 % (ES), understaging in 0 % (EMRI) and 7 % (ES). The highest diagnostic accuracy was shown in EMRT in patients with rectal adenoma and rectal carcinoma (pT1) and after electro-laser resection or transanal resection during follow-up. CONCLUSIONS: Contrast enhanced endorectal MR imaging appears to be very promising for accurate posttherapeutical staging of rectal cancer and helpful in the diagnosis of recurrence or the differentiation between scar tissue and residual rectal tumor.

Adenoma↗
PubMed2002

[Quantitative analysis of cardiovascular interactions in patients with cardiomyopathy and after myocardial infarct].

The aim of this study was to detect pathological changes of the complex autonomous regulation of ecg, blood pressure and respiration (synchronously recordings of 30 minutes) in patients with cardiac diseases. We investigated the cardiovascular and cardiorespiratory linear and nonlinear interactions in 10 patients with dilative cardiomyopathy (dcm) and in 10 patients after myocardial infarction (mi). We compared results from the classical linear correlation function analysis with results from the mutual information method (transinformation) for analysis of nonlinear and linear interactions. Both methods yield high significant parameters (p < 0.01). Thus, we found both linear and nonlinear interactions with partly different specificity in patients with dcm and mi compared to healthy subjects (ref).

Blood Pressure Monitors↗