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Biomedical subjects

S Schwab

Publications and source records attributed to S Schwab.

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

[Extrajudicial expert assessment--what is the basis for complaints against internists?].

In 1981, the Swiss Medical Association (FMH) set up an expert medical evidence office, from which patients or their dependents could request an extra-judicial expert report in cases of suspected error in diagnosis or treatment. Up to the year 1995, this office issued a total of 1675 expert reports, of which 109 were for the specialty of Internal Medicine. Since the office was founded, the number of expert witnesses called upon has continued to increase. The most common accusation was "failure to investigate or delay in investigation" (41 times, 48.2%) followed by the accusation of a "diagnostic error" (35 times, 41.2%). In 13 cases (20%) the expert report confirmed there had been a medical error, 46 (70.8%) negated such a finding, and no firm conclusion was reached in 6 expert reports (9.2%). Expert reports are very often requested by patients with malignant neoplasms, particularly if the disease is first diagnosed at an advanced stage, and these are associated with the most frequent accusation of delayed investigation. Communication problems between doctor and patient are a recurrent theme throughout the expert reports and this shows the importance of taking the patient's concerns seriously, of a well-founded explanation, and of being ready to discuss matters.

Expert Testimony↗
PubMed1999

Brain-derived neurotrophic factor prevents neuronal death and glial activation after global ischemia in the rat.

The expression of brain-derived neurotrophic factor (BDNF) and its receptor tyrosine kinase B are both increased after global ischemia. Therefore, a protective action of BDNF against the delayed degeneration of vulnerable neurons has been suggested. We have investigated the neuroprotective action of BDNF in global ischemia induced by a four-vessel occlusion in the rat. Following reperfusion, 0.06 microg/hr BDNF was continuously administered intracerebroventricularly with an osmotic minipump. Rats were sacrificed up to 7 days after ischemia and neuronal degeneration was identified by terminal transferase and biotin-dUTP nick end labeling (TUNEL) staining. Additionally, the glial reaction was investigated immunohistochemically and by measuring the activation of immunological nitric oxide synthase protein expression. Postischemic intracerebroventricular infusion of BDNF prevented neuronal death in the vulnerable CA1 region of the hippocampus. Additionally, astroglial activation and macrophage infiltration, which were observed in association with neuronal death, were inhibited by BDNF. This was paralleled by an inhibition of inducible nitric oxide synthase (iNOS) expression in the hippocampus. Thus, the observed neuroprotective effects of continuous BDNF administration after reperfusion suggest a therapeutic potential for BDNF in cerebral ischemia.

Animals↗
PubMed1999

Epstein-Barr virus meningoencephalitis with a lymphoma-like response in an immunocompetent host.

We report the clinical and neuropathological findings in an immunocompetent 19-year-old patient with a fatal acute Epstein-Barr virus (EBV) meningoencephalitis and a lymphoma-like B-lymphocyte response. Our results suggest that an immunotoxic rather than direct viral neuronal invasion mediates brain damage in EBV encephalitis and rule out primary central nervous system lymphoma (PCNSL) in our patient. We discuss immunosuppression as a therapeutic option, because present strategies mainly consist of symptomatic therapy due to unclear pathogenesis and nonavailability of effective antiviral agents.

Adolescent↗
PubMed1999

Brain-derived neurotrophic factor improves long-term potentiation and cognitive functions after transient forebrain ischemia in the rat.

We investigated the effect of brain-derived neurotrophic factor (BDNF) on hippocampal long-term potentiation (LTP) and cognitive functions after global cerebral ischemia in the rat. After four-vessel occlusion, BDNF was administered via an osmotic minipump continuously over 14 days intracerebroventricularly. Electrophysiological experiments were performed 14 days after cerebral ischemia. Test stimuli and tetanization were delivered to the Schaffer collaterals of the hippocampus and field excitatory postsynaptic potentials (fEPSP) were recorded in the CA1 region. Cognitive impairment was analyzed repeatedly with a passive avoidance test, a hole-board test, and with an activity center on the same animal. In sham-operated animals, LTP was consistantly induced after delivering a tetanus (increase of initial slope of fEPSP to 173 +/- 12% of baseline; n = 6). After transient forebrain ischemia LTP could not be induced (117 +/- 4% of baseline; n = 7). In ischemic animals treated with BDNF, LTP could be induced (168 +/- 28% of baseline; n = 8). Transient forebrain ischemia resulted in a significant decrease in spatial discrimination performance but not of associative memory. The ratios for working memory (WM) and reference memory (RM) 15 days after ischemia were lower in the ischemic rats (n = 10) than in the sham-operated control animals (n = 10; WM: 22 +/- 6 vs 72 +/- 7; RM: 30 +/- 7 vs 72 +/- 5). Postischemic intracerebroventricular BDNF infusion increased both WM (63 +/- 4; n = 10) and RM (58 +/- 5; n = 10). The spontaneous locomotor activity did not differ significantly in the three groups. These data indicate a protective effect of BDNF for synaptic transmission and cognitive functions after transient forebrain ischemia.

Animals↗
PubMed1999

[Status epilepticus. Rational diagnosis and current therapeutic concepts].

Status epilepticus (SE) is defined as a seizure persisting over 10 min or repeated seizures without recovery between the attacks. SE is a frequent medical emergency with a high mortality, requiring aggressive and prompt treatment and a systematic, coordinated approach. A variety of new drugs has been introduced for the treatment of SE, including midazolam, propofol, fosphenytoin, and valproate. However, there are very few controlled clinical trials. Benzodiazepines are highly effective in terminating the SE in most patients and should be used as initial treatment. Phenytoin and Phenobarbital are employed if Benzodiazepines are not successful. The optimal therapeutic approach for the patient with refractory SE remains to be defined. Refractory SE has a poor prognosis and should be treated in a specialized ICU with EEG-monitoring. Barbiturates, propofol, and midazolam are substances that can be used alternatively.

Humans↗
PubMed1999

[Enzyme defects of the urea cycle in differential acute encephalopathy diagnosis in adulthood. Diagnosis and current therapy concepts].

Six enzyme defects of the urea cycle have been described. Ornithine transcarbamylase deficiency is the most frequent of these diseases. The cumulative frequency is 1:8000. Most patients become symptomatic in childhood, but onset of symptoms may occur later in childhood or even adulthood. The patients present with recurrent episodes of an unspecific acute encephalopathy, seizures and clouding of consciousness to a variable degree. Focal neurological signs such as hemiparesis, aphasia or ataxia may also occur. These episodes may be triggered by infection, protein overload or drugs. Diagnostic are increased blood ammonia levels. Characteristic patterns of plasma amino acids and the determination of orotic acid in the urine mostly discriminate the individual disorders. Further diagnostic steps include the allopurinol challenge test, liver or skin biopsy for measurement of enzyme activity and molecular genetic studies. Treatment requires restriction of protein intake, supplementation of arginine and activation of alternative pathways of nitrogen excretion with benzoate or phenylbutyrate. Untreated, the acute episode may be lethal. Long-term treatment improves the clinical outcome considerably. Urea cycle defects should be included in the differential diagnosis of any encephalopathy or coma of unclear origin, and blood ammonia should be determined early in the evaluation of such patients.

Adult↗
PubMed1999

[Fibrinolysis of intraventricular hematoma with rt-PA].

Intraventricular administration of recombinant tissue plasminogen activator (rt-PA) is an experimental therapy to hasten the lysis of intraventricular hemorrhages. We report nine patients (7 male, 2 female, mean age 64a) with intracerebral hematoma with ventricular extension who were treated with intraventricular infusion of rt-PA (2-32 mg, mean dose 17 mg). In two patients, clinically significant bleeding complications were associated with the fibrinolytic therapy. In one of these patients, fibrinolytic therapy was stopped. Other complications could not be observed. In eight of all nine patients, a rapid and extensive reduction of the amount of intraventricular blood occurred. A persistent shunt became necessary in two patients. We conclude, that intraventricular fibrinolysis probably leads to a faster clearance of intraventricular blood. Despite of fibrinolytic treatment, a permanent shunt becomes necessary in some cases. Intraventricular fibrinolysis is a potentially hazardous therapy with the risks of bleeding complications and infection.

Adult↗
PubMed1999

[Moderate hypothermia for the treatment of malignant middle cerebral artery infarct].

Moderate hypothermia was induced in 30 patients with malignant middle cerebral artery (MCA) territory infarction. Patients were kept at 33 degrees C body-core temperature for 48 to 72 h, and ICP, CPP, and brain temperature were monitored. Outcome at 4 weeks and at 3 months after the stroke as well as side effects of moderate hypothermia were analysed. Mortality of malignant MCA infarction could be reduced from 80% in historical controls, to 43% (13/30) under hypothermia. During hypothermia elevated ICP values could be significantly reduced. Herniation due to a secondary rise of ICP after rewarming was the cause of death in all 13 patients. The most frequent complication of moderate hypothermia was pneumonia in 12 of the 30 patients (40%). Other severe side effects of hypothermia could not be detected. Moderate hypothermia may improve clinical outcome in patients with malignant MCA infarction.

Adolescent↗
PubMed1999

[Genetics of schizophrenic disorders. New concepts and findings].

Schizophrenia is a genetic complex disease as it does not follow monogenic transmission while non-familial environmental factors have a strong additional impact. A heterogeneous, continuous phenotype is transmitted in families which can now be more precisely characterized. Genes coding for proteins with presumed pathophysiological relevance are apparently not playing a major causal role. However, in the last three years several (currently seven) candidate regions have been identified in a replicable manner by linkage studies. These regions are likely to host susceptibility genes for schizophrenia, but none of them has been identified up to now. Given these findings, polygenic transmission has now become very likely. The candidate regions are currently being narrowed down by various promising techniques.

Biomarkers↗
PubMed1999

Presentation of out-of-frame peptide/MHC class I complexes by a novel translation initiation mechanism.

Immune surveillance by CD8 T cells requires that peptides derived from intracellular proteins be presented by MHC class I molecules on the target cell surface. Interestingly, MHC molecules can also present peptides encoded in alternate translational reading frames, some even without conventional AUG initiation codons. Using T cells to measure expression of MHC bound peptides, we identified the non-AUG translation initiation codons and established that their activity was at the level of translational rather than DNA replication or transcription mechanisms. This translation mechanism decoded the CUG initiation codon not as the canonical methionine but as the leucine residue, and its activity was independent of upstream translation initiation events. Naturally processed peptide/MHC complexes can thus arise from "noncoding" mRNAs via a novel translation initiation mechanism.

Amino Acid Sequence↗
PubMed1999

Favorable recovery from bilateral loss of somatosensory evoked potentials.

OBJECTIVES: Bilateral loss of the cortical somatosensory evoked potentials (SEP) is usually regarded as a strong predictor for a very poor clinical outcome. We present four patients with a favorable recovery from bilaterally absent cortical SEP. DESIGN: Case series. SETTING: Neurocritical care unit at the University of Heidelberg. PATIENTS: Four patients with viral encephalitis, carbamazepine intoxication, head trauma, and left-side, space-occupying hemispheric infarction, respectively. INTERVENTIONS: Serial recording of somatosensory and auditory evoked potentials, therapy of increased intracranial pressure, including decompressive surgery, hypothermia, and barbiturate coma. MEASUREMENTS AND MAIN RESULTS: Three patients had an excellent outcome (Glasgow Outcome Scale 4 and 5). In those three patients, the SEP became completely normal during the clinical course. In one patient who remained severely disabled, the SEP became detectable again over the contralateral hemisphere, but remained abnormal. Possible influencing factors were sedative and analgetic drugs in all patients, and hypothermia and barbiturate coma in one of the patients. CONCLUSIONS: The absence of cortical SEP does not invariably imply an unfavorable prognosis. Absent cortical SEP indicates a severe neuronal dysfunction, which may be completely reversible if the underlying disease does not lead to permanent structural damage.

Acute Disease↗
PubMed1999

Dialysis or transplantation: fitting the treatment to the patient.

Early referral of the patient with chronic renal failure will give the nephrologist time to fit the treatment to the patient. Planning for dialysis and transplantation should be undertaken concurrently. If the patient is not of advanced age and is not afflicted with severe comorbid illness, renal transplantation is the preferred form of renal replacement therapy. Living donor transplantation is preferred to cadaveric transplantation. For the patient who awaits or who cannot undergo transplantation, either peritoneal dialysis or hemodialysis may be chosen. Although the mortality rate for peritoneal dialysis appears to be higher than that for hemodialysis, especially among elderly diabetic patients, peritoneal dialysis remains an acceptable therapy for the highly motivated patient. In the United States, the mortality rate for chronic dialysis patients is high. We expect mortality rates for both peritoneal dialysis and hemodialysis to fall, however, as we strive to achieve optimal solute clearance and to more effectively treat comorbid illness.

Age Factors↗
PubMed1999

Familial hemiplegic migraine with cerebellar ataxia and paroxysmal psychosis.

Familial hemiplegic migraine is a rare autosomal dominant disorder associated with stereotypic neurologic aura phenomena including hemiparesis. So far two chromosomal loci have been identified. Families linked to the chromosome 19 locus display missense mutations within the CACNL1A4 gene. Here we report on a family with familial hemiplegic migraine and cerebellar ataxia with recurrent episodes of acute paranoid psychosis with anxiety and visual hallucinations associated with migraine attacks. Based on the clinical and haplotype evidence indicating linkage to chromosome 19 in this family, we hypothesize that a dysfunction of the mutated calcium channel may be involved not only in the development of hemiplegic migraine but also in the acute psychotic episodes observed in these patients.

Adolescent↗
PubMed1999

Neurochemical monitoring of fatal middle cerebral artery infarction.

BACKGROUND: Microdialysis is a method for neurochemical monitoring that has been applied more frequently over the past few years in patients suffering from subarachnoid hemorrhage, acute brain injury, and stroke. It is used to study the course of extracellular molecules of low molecular weight, such as excitatory amino acids or metabolic end products. CASE DESCRIPTION: We report the case of a 43-year-old patient suffering from left hemispheric stroke with a space-occupying postischemic edema leading to a considerable mass effect on the contralateral side. For treatment of severe edema, hypothermia was initiated. The microdialysis and intracranial pressure probe were placed into the noninfarcted hemisphere. A massive increase in levels of glutamate, glycerine, and the lactate-pyruvate ratio was measured 24 hours before intracranial pressure elevation was observed and brain death occurred. CONCLUSIONS: Monitoring excitatory amino acids, glycerine as a membrane component, and lactate-pyruvate ratio as an energy marker by microdialysis is a useful tool to increase our understanding of biochemical events in secondary brain damage. For future prevention of secondary ischemia in patients with massive stroke, close neurochemical monitoring might be valuable to improve therapy, particularly in the critically ill.

Adult↗