[Nephropathies are treated too late. 10,000 dialysis patients could have healthy kidneys].
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Germany↗
Biomedical subjects
M Weber
Publications and source records attributed to M Weber.
Simultaneous detection of ubiquinol-10, ubiquinone-10, and tocopherols in human plasma microsamples and macrosamples as a marker of oxidative damage in neonates and infants.
A HPLC-method was developed for the simultaneous detection of the lipophilic antioxidants ubiquinol-10, ubiquinone-10, alpha-tocopherol, and gamma-tocopherol in plasma macrosamples (100 microl) as well as microsamples (10 microl) using electrochemical detection with internal standardization (gamma-tocotrienol, ubiquinol-9, ubiquinone-9). The use of a mobile phase containing ammonium formate instead of lithium perchlorate as conductivity salt and the use of a PEEK column instead of a steel column improved the reproducibility of the method. The components were separated on a RP C18 column. The detection limits for all components were between 1 and 28 fmol. The within-day precision varied between 3 and 13% for all measured substances. The analytical recovery was between 93 and 109%. The plasma levels from 10 healthy donors were determined in microsamples and macrosamples taken by micropuncture or venous puncture, respectively. A good correlation of the antioxidant levels for both methods strengthened the reliability and the transferability of the results. The present method can be used to assess the role of these antioxidants in diseases associated with oxidative damage in childhood.
Antioxidants↗
Mapping the Hawaiian plume conduit with converted seismic waves
The volcanic edifice of the Hawaiian islands and seamounts, as well as the surrounding area of shallow sea floor known as the Hawaiian swell, are believed to result from the passage of the oceanic lithosphere over a mantle hotspot. Although geochemical and gravity observations indicate the existence of a mantle thermal plume beneath Hawaii, no direct seismic evidence for such a plume in the upper mantle has yet been found. Here we present an analysis of compressional-to-shear (P-to-S) converted seismic phases, recorded on seismograph stations on the Hawaiian islands, that indicate a zone of very low shear-wave velocity (< 4 km s(-1)) starting at 130-140 km depth beneath the central part of the island of Hawaii and extending deeper into the upper mantle. We also find that the upper-mantle transition zone (410-660 km depth) appears to be thinned by up to 40-50 km to the south-southwest of the island of Hawaii. We interpret these observations as localized effects of the Hawaiian plume conduit in the asthenosphere and mantle transition zone with excess temperature of approximately 300 degrees C. Large variations in the transition-zone thickness suggest a lower-mantle origin of the Hawaiian plume similar to the Iceland plume, but our results indicate a 100 degrees C higher temperature for the Hawaiian plume.
Journal Article↗
Identification of a penta- and hexapeptide of islet amyloid polypeptide (IAPP) with amyloidogenic and cytotoxic properties.
Pancreatic amyloid is found in more than 95 % of type II diabetes patients. Pancreatic amyloid is formed by the aggregation of islet amyloid polypeptide (hIAPP or amylin), which is a 37-residue peptide. Because pancreatic amyloid is cytotoxic, it is believed that its formation is directly associated with the development of the disease. We recently showed that hIAPP amyloid formation follows the nucleation-dependent polymerization mechanism and proceeds via a conformational transition of soluble hIAPP into aggregated beta-sheets. Here, we report that the penta- and hexapeptide sequences, hIAPP(23-27) (FGAIL) and hIAPP(22-27) (NFGAIL) of hIAPP are sufficient for the formation of beta-sheet-containing amyloid fibrils. Although these two peptides differ by only one amino acid residue, they aggregate into completely different fibrillar assemblies. hIAPP(23-27) (FGAIL) fibrils self-assemble laterally into unusually broad ribbons, whereas hIAPP(22-27) (NFGAIL) fibrils coil around each other in a typical amyloid fibril morphology. hIAPP(20-27) (SNNFGAIL) also aggregates into beta-sheet-containing fibrils, whereas no amyloidogenicity is found for hIAPP(24-27) (GAIL), indicating that hIAPP(23-27) (FGAIL) is the shortest fibrillogenic sequence of hIAPP. Insoluble amyloid formation by the partial hIAPP sequences followed kinetics that were consistent with a nucleation-dependent polymerization mechanism. hIAPP(22-27) (NFGAIL), hIAPP(20-27) (SNNFGAIL), and also the known fibrillogenic sequence, hIAPP(20-29) (SNNFGAILSS) exhibited significantly lower kinetic and thermodynamic solubilities than the pentapeptide hIAPP(23-27) (FGAIL). Fibrils formed by all short peptide sequences and also by hIAPP(20-29) were cytotoxic towards the pancreatic cell line RIN5fm, whereas no cytotoxicity was observed for the soluble form of the peptides, a notion that is consistent with hIAPP cytotoxicity. Our results suggest that a penta- and hexapeptide sequence of an appropriate amino acid composition can be sufficient for beta-sheet and amyloid fibril formation and cytotoxicity and may assist in the rational design of inhibitors of pancreatic amyloid formation or other amyloidosis-related diseases.
Amino Acid Sequence↗
Focal myopathy induced by chronic heroin injection is reversible.
We report a patient who developed a focal myopathy with prominent contractures of his thigh muscles induced by chronic heroin injection. Muscle biopsy and magnetic resonance imaging (MRI) were indicative of a fibrotic and inflammatory process. Treatment with steroids, D-penicillamine, and physical therapy led to full functional recovery within 6 months. Sequential electromyographic (EMG) studies and muscle biopsies showed evidence of regenerating muscle fibers and absence of inflammatory cells. We conclude that heroin-induced focal myopathy is reversible and that combination therapy with D-penicillamine and steroids may be useful.
Adult↗
Complex fasciculations and their origin in amyotrophic lateral sclerosis and Kennedy's disease.
Complex fasciculations are common in patients with amyotrophic lateral sclerosis (ALS). Combined fasciculations, defined as a complex fasciculation consisting of two or more components that occur independently but also in combination with another component, also occur in ALS. To test the hypothesis that combined fasciculations originate at the supraspinal level, we analyzed 2681 fasciculation potentials from 17 patients with definite or probable ALS by the El Escorial criteria. Results were compared with 304 fasciculation potentials recorded from 6 patients with Kennedy's disease, in which the upper motoneurons are spared. The mean firing frequency of the fasciculations was 24.4 +/- 25.6 per minute in ALS, significantly higher than the 2.9 +/- 3.4 per minute found in Kennedy's disease (P < 0.0001). In ALS, the mean combination ratio (the number of times that a combined fasciculation occurred divided by the total number of fasciculations) was 4.6 +/- 8.3% (range 0-33). Fourteen of 17 ALS patients had combined fasciculations, but only one combined fasciculation was found in a patient with Kennedy's disease. Combined fasciculations are distinctive in ALS, and we hypothesize that they are triggered by a supraspinal mechanism reflecting dysfunction of descending motor pathways.
Electromyography↗
Conditioned changes in ultrasonic vocalizations to an aversive olfactory stimulus are lateralized in 6-day-old rats.
Using a soft rubber plug to block airflow in one naris, Kucharski, Johanson, and Hall (1986) found that some forms of olfactory memory (e.g., odor preferences) were lateralized in young rats while other forms (e.g., conditioned activation and mouthing) were not. The present experiments extended that research by showing that conditioned increases in ultrasonic vocalizations were also lateralized. That is, when exposed to an odor that was previously paired with footshock, 6-day-old rats significantly increased their rate of vocalizing. This response only occurred, however, when the naris open at training was also open at test. The use of the developing rat as a natural split-brain preparation appears to be an effective procedure with which to broaden current approaches to the analysis of learning, memory, and emotion.
Age Factors↗
Sporadic case of X-chromosomal Alport syndrome in a consanguineous family.
Alport syndrome (AS) is a genetic disorder of basement membranes caused by mutations in type IV collagen genes that is characterized by chronic hematuria and progressive nephropathy leading to renal failure. The main extrarenal features include sensorineural hearing loss and ocular lesions. The mode of inheritance is X-linked dominant in about 80%-85% of the affected families, whereas autosomal transmission is rarely encountered. We report a male patient originating from a healthy consanguineous Lebanese family who presented with an unusual association of obstructive uropathy and AS. Hematuria and proteinuria were initially attributed to a suspected poststreptococcal glomerulonephritis (GN) and high-grade subpelvic ureteral stenosis. Persistence of symptoms after medical treatment of poststreptococcal GN and surgical correction of obstructive uropathy finally led to renal biopsy. The observed ultrastructural changes of the glomerular basement membrane were typical for AS. Molecular genetic studies revealed a previously undescribed de novo mutation in the COL4A5 gene, excluding maternal heterozygotic carrier status. This case report emphasizes the importance of hereditary nephritis in the differential diagnosis of chronic hematuria, and demonstrates the value of molecular studies for genetic counselling in AS.
Basement Membrane↗
[Somatoparaphrenia. A positive variant of anosognosia for hemiplegia].
Anosognosia for hemiplegia (AHP), i.e., unawareness of motor deficits and associated disorders, has been frequently reported, pre-dominantly following right hemispheric lesions. To a smaller extent, there are case reports of patients who give accounts of a feeling of strangeness concerning the contralesional limbs and sometimes attribute them to other persons. This "positive-variant" of AHP has been labeled "somatoparaphrenia" (SP). We report a case of SP in a 85-year-old woman with infarction of the right posterior cerebral artery and posterior parts of the right thalamus. She showed AHP and described her left side alternatively as her handicapped nephew and a clumsy cat. Misidentification of her daughter also occurred. With respect to the literature the predominant neuroanatomical features involved are lesions including right parietal cortex and/or posterior parts of the thalamus. Theories concerning the pathogenesis of this phenomenon comprise a denial of the illness, a lack of awareness caused by reduced sensory feedback and neglect, a misidentification or disturbance of the active discovery process considered necessary for realizing one's disorder.
Aged↗
Experimental tissue acidosis leads to increased pain in complex regional pain syndrome (CRPS).
The aim of this study was to investigate the role of local acidosis in the generation of pain in complex regional pain syndrome (CRPS). We investigated ten patients with CRPS of the upper extremity with a mean duration of the disease of 43 weeks (range 4-280 weeks) and ten control subjects for sensitivity to infusion of fluids with low pH (pH 6.1). Another group of five CRPS patients and three healthy controls was investigated using the same protocol but neutral infusion fluid (pH 7.4). A motorized syringe pump was installed for a constant infusion of synthetic interstitial fluid (SIF, either acidified (pH 6.1) or neutral) into the skin at the back of the hands and, thereafter, into the interosseus I muscle on both sides. A flow rate of 30 ml/h was chosen for intradermal and 7.5 ml/h for intramuscular infusion over a period of 10 min. The magnitude of pain was rated on an electronic visual analogue scale. Patients were requested to give their ratings every 10 s during the whole stimulation period. The ratings were normalized as fractions of individual grand mean values. We found significantly increased pain perception during infusion of acidified SIF on the affected side in CRPS patients. Low pH fluid into the skin was significantly more painful between 4 and 6 min (ipsi 1.27 normalized rating (NR) (0. 19-1.94), contra 0.31 NR (0.03-0.51), P<0.02) and between 8 and 10 min (ipsi 1.38 NR (0.19-1.94), contra 0.08 NR (0-0.27), P<0.03) on the affected side, while analysis over the whole stimulation period just failed to reach statistical significance (ipsi 281 area under the curve (AUC) (187-834), contra 87 AUC (28-293), P=0.059). Low pH infusion into the muscle was significantly more painful on the affected side during the whole infusion time (ipsi 861 AUC (308-1377), contra 190 AUC (96-528), P<0.01). The quality of the deep pain during infusion into the muscle was described by the patients as very similar to the CRPS-related pain. In controls we found no side differences of pain intensity during low pH stimulation. Neutral SIF evoked no pain at all, neither in CRPS patients (ipsi 0 AUC, contra 0 AUC) nor in healthy controls. Our results suggest that hyperalgesia to protons is present in patients with CRPS. Further, we could demonstrate that pain is not only restricted to the skin but is also generated in deep somatic tissue of the affected limb.
Acidosis↗
Clusters of ventricular tachycardias signify impaired survival in patients with idiopathic dilated cardiomyopathy and implantable cardioverter defibrillators.
OBJECTIVES: This retrospective study was undertaken to provide data on occurrence, significance and therapy of ventricular tachyarrhythmia (VT) clusters (VTCs) in patients with dilated cardiomyopathy (DCM) and implantable cardioverter defibrillators (ICDs). BACKGROUND: Data on the clinical significance of VTCs are lacking in patients with DCM and ICDs. METHODS: Baseline characteristics of 106 consecutive patients with DCM and ICDs were prospectively collected, and chart reviews and episode data retrospectively analyzed. A VTC was defined as > or =3 sustained VTs/24 h. RESULTS: During a mean follow-up of 33+/-23 months, 73 patients (68.9%) had recurrent VT or ventricular fibrillation (VF), 43 patients (40.6%) suffered only single VTs and 30 patients (28.3%) experienced 52 clusters of VTs. Actuarial survival free of VT or VF was 44.6%, 33.0% and 26.5%, and survival free of VTC was 77.3%, 72.2% and 67.1% after one, two and three years, respectively. Independent predictors of VT clusters were heart failure before ICD implantation (p = 0.033), presenting monomorphic VT (p = 0.044), EF <0.40 (p = 0.014) and inducible mVT, especially with right bundle branch block and superior axis configuration (p<0.001). Survival free of recurrent VTCs was 50.8%, 38.1% and 19.0% after one, two and three years, respectively. Once a VTC had occurred, only 56.7%, 46.4%, 30.9% and 15.5% of patients survived and were not transplanted after one, two, three and four years, respectively. Survival was even more reduced if a VTC was associated with cardiac decompensation: 65.6% and 21.9% after one and two years, respectively. CONCLUSIONS: Despite antiarrhythmic intervention, clusters of VTs occur and recur frequently in patients with DCM. They signify impaired survival, especially if they are associated with cardiac decompensation, and may be a harbinger of progressive myocardial deterioration rather than a primarily arrhythmic problem. The benefit of ICD therapy may therefore be low in these patients.
Aged↗
Corticomotoneuronal activity in ALS: changes in the peristimulus time histogram over time.
OBJECTIVE: The primary peak in the peristimulus time histogram (PSTH) reflects the initial rising phase of the excitatory post-synaptic potential (EPSP) evoked at the anterior horn cell. In ALS the primary peak is delayed in onset. increased in duration and desynchronized. abnormalities reflecting dysfunction of the corticomotoneurons. It is not known whether these abnormalities change over time in amyotrophic lateral sclerosis (ALS). METHODS: PSTHs were constructed from changes in the firing probability of single, voluntarily activated motor units subjected to subthreshold transcranial magnetic stimuli. We studied 58 motor units in 12 patients with ALS on two separate occasions (mean time interval of 10.6 +/- 1.6 months). Results were compared with 49 motor units in 11 age matched controls. RESULTS: All the parameters except the amplitude differed significantly between normals and patients. In general the primary peak in ALS was complex, desynchronized and occasionally consisted of a double peak. The abnormalities persisted or were accentuated at tile follow up visit. This was reflected by an increase in the number of excess bins, longer duration and latency and decrease of synchrony. CONCLUSIONS: Increasing desynchronization of the primary peak over time in ALS reflects dysfunction of the monosynaptic corticomotoneuronal pathway and may also reflect activation of additional slow conducting and/or polysynaptic corticomotoneuronal connections.
Adult↗
Are motor evoked potentials (MEPs) helpful in the differential diagnosis of spondylotic cervical myelopathy (SCM)?
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Diagnosis, Differential↗
The structure of a pyoverdine from Pseudomonas sp. CFML 96.188 and its relation to other pyoverdines with a cyclic C-terminus.
From Pseudomonas sp. CFML 96.188 a pyoverdine was isolated and its primary structure was elucidated by spectroscopic methods and degradation reactions. This strain is of interest as it accepts the structurally different pyoverdines from several other Pseudomonas strains. They all have in common as a specific structural feature a C-terminal cyclic substructure, the importance of which for the recognition of a pyoverdine at the cell surface of a given strain will be discussed.
Amino Acid Sequence↗
[Principles of surgical treatment of morbid obesity].
The incidence of morbid obesity has steadily increased over the last few years. Although conservative treatment of morbidly obese patients made some progress (e.g. Xenical), a persistent weight reduction can hardly be achieved in these patients. The possibility of a minimal invasive approach lead to a revival of the surgical therapy of morbid adiposity. The laparoscopic gastric banding became an attractive therapy for patients presenting with a body mass index greater than 40 kg/m2. However, the long-term follow-up after laparoscopic gastric banding increasingly shows the limit of this surgical approach and emphasises the importance of a determined preoperative patient selection. This article reviews the clinical basics and functional mechanisms of different surgical methods to treat morbid obesity comparing their advantages and disadvantages. Due to the widely and nowadays very popular application of laparoscopic gastric banding, this operative method is described in detail.
Anastomosis, Roux-en-Y↗
Primary small bowel carcinoma--case report.
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Adenocarcinoma↗
Neurological findings in complex regional pain syndromes--analysis of 145 cases.
Early diagnosis is a prerequisite for a successful treatment of complex regional pain syndrome (CRPS). In order to describe neurological symptoms which characterize CRPS, we evaluated 145 patients prospectively. Two-thirds of these were women, the mean age at time of investigation was 50.4 years. CRPS followed limb trauma, surgery and nerve lesion. Employing the current IASP criteria 122 patients were classified as CRPS I and 23 as CRPS II. All patients were assessed clinically pain was quantified using the McGill pain questionnaire, skin temperature was measured by an infrared thermometer and a subgroup of 57 patients was retested in order to determine thermal thresholds (QST). Of our patients 42% reported stressful life events in a close relationship to the onset of CRPS and 41% had a history of chronic pain before CRPS. The latter group of patients gave a higher rating of CRPS pain (P<0.05). The major symptoms were pain at rest in 77% and hyperalgesia in 94%. Typical pain was deep in the limb having a tearing character. Patients getting physical therapy had significantly less pain than those without (P<0.04). Autonomic signs were frequent (98%) and often changed with the duration of CRPS. Skin temperature was warmer in acute and colder in chronic stages (P<0.001). Likewise edema had a higher incidence in acute stages (P<0.001). We found no correlation between pain and autonomic dysfunction. Motor dysfunction (present in 97%) included weakness, tremor, exaggerated tendon reflexes, dystonia or myoclonic jerks. QST revealed increased warm perception thresholds (P<0.02) and decreased cold pain thresholds (P<0.03) of the affected limb. The detailed knowledge of clinical features of CRPS could help physicians early to recognize the disease and thus to improve therapy outcome.
Adolescent↗
Are anaphylactic reactions to snake bites immunoglobulin E-mediated?
BACKGROUND: Bites by poisonous European snakes of the genus Vipera lead to local tissue damage and systemic symptoms such as generalized oedema, hypotension, gastrointestinal symptoms, haemolysis and renal dysfunction. Not rarely anaphylactic symptoms like urticaria, localized angioedema and asthma are observed. OBJECTIVE: To look for snake venom-specific immunoglobulin (Ig) E antibodies in patients with a history of bites by European vipers and for cross-reactions with Hymenoptera venoms, that have a similar composition. METHOD: Ten patients with a history of bites by Vipera aspis or Vipera berus were investigated. Three patients had been bitten only once, and two of these had developed only local reactions. Four reported previous allergic reactions to Hymenoptera stings. All patients, 10 Hymenoptera venom-allergic and five nonallergic individuals who served as controls underwent i.c. skin test endpoint titration with snake (V. aspis, V. berus) and Hymenoptera venoms (honey bee, Vespula spp.) and were investigated for specific serum IgE antibodies to the same venoms. RESULTS: Seven of the eight patients with systemic snake bite reactions had both positive skin tests and serum IgE antibodies to snake venoms, while these tests were negative in the two patients with only local reactions to snake bites and all controls. Seven of the eight patients with systemic snake bite reaction also had positive skin tests and specific IgE with one or both Hymenoptera venoms. By RAST-inhibition with sera of four patients with high IgE to both Vipera and Hymenoptera venoms, partial cross-reactivity could be demonstrated in one. CONCLUSIONS: Anaphylactic reactions following snake bites may be IgE-mediated, especially in patients with repeated bites.
Adult↗