Functional characterization of a novel mutation localized in the start codon of the tissue-nonspecific alkaline phosphatase gene.

Hypophosphatasia (HPP) is a rare inborn disease caused by different mutations in the tissue-nonspecific alkaline phosphatase (ALPL) gene. Previous studies showed that gene mutations could exhibit a dominant negative effect leading to a mild HPP phenotype in heterozygous carriers. In the present report we describe the clinical and functional studies of a novel mutation localized in the start codon of transcript variant 1 of the ALPL gene from a female adult heterozygous carrier. The mutation results in translation of an N-terminally truncated protein, which might be identical to the deduced protein from ALPL transcript variant 2. When overexpressed in HEK-293 cells it does not exhibit any enzymatic activity and has no significant effect on the wild type ALPL protein. Furthermore it is not attached to the cell membrane. Due to the loss of the signal peptide an intracellular misrouting and a premature degradation is obvious. Hence the new isoform deposited in the database does not produce an active protein as it is the case in the natural mutation of our patient. Since the mutation does not produce a dominant negative protein in heterozygous carriers, the clinical phenotype in our patient and her relatives is very mild with only unspecific myalgia. However the patient developed bone marrow edema of both femoral heads during lactation after delivery of a healthy child, indicating a risk to develop alterations of bone metabolism in challenge situations. Her sister complains of identical symptoms, her father shows distinct symptoms of odonto-hypophosphatasia. The question if or if not carriers of ALPL mutations in general or only with distinct genotypes can be symptomatic in normal life or in challenge situations requires systematic clinical studies.

[Idiopathic thunderclap headache: reversible vasospasm of the Arteria basilaris]. / Primärer Donnerschlagkopfschmerz: Reversibler Vasospasmus der Arteria basilaris.

Thunderclap headache describes a rare headache syndrome characterized by abrupt-onset severe headache mimicking subarachnoidal bleeding, which has to be excluded by adequate diagnostic procedures such as digital subtraction angiography. The pathophysiology is still not clear but there are an increasing number of reports which describe some kind of vasospasm of the intracranial arteries during the headache episode. Here we describe a patient with a thunderclap headache and a mid-basilar narrowing due to a reversible vasospasm.

[Acute airway obstruction in acquired hemophilia A]. / Akute Atemwegsverlegung durch erworbene Hämophilie A.

We report the case of a 67 year old patient suffering from acute airway obstruction caused by hemorrhage localized to the tongue, mouth cavity and hypopharynx, with no evidence of bleeding in his history. The patient presented initially with a globus feeling of the neck, dysphagia and a sore throat. CT scan revealed a swelling of the lingual and sublingual areas and the pharyngeal wall. Next day, there was an immediate life-threatening event caused by progressive bleeding with airway obstruction and an inability to intubate requiring coniotomy. The etiology of the hemorrhage was confirmed by finding a depletion of factor VIII and the presence of auto-antibody directed against this factor. Based on this case report and a review of the literature, we discuss the diagnosis and treatment of acquired hemophilia.

[Molecular variants of fibrinogen]. / Molekulare Varianten des Fibrinogens.

In the final step of blood coagulation, fibrin monomers polymerize spontaneously and are covalently linked by factor XIIIa. Mutations in one of the three genes coding for the fibrinogen peptides may disturb this process and lead to diseases such as afibrinogenemia or dysfibrinogenemia, or may even cause hereditary renal amyloidosis. In the brief overview presented here we summarize some of the molecular aspects of these diseases.

Activated protein C resistance and acute ischaemic stroke: relation to stroke causation and age.

OBJECTIVES: Resistance to activated protein C (APC) is the most frequent cause of thrombophilia and a well known risk factor for deep and cerebral vein thrombosis. Its causative role in ischaemic stroke is still a matter of debate. We undertook this study to determine the prevalence of APC-resistance in a cohort of consecutive patients with acute ischaemic stroke, especially with respect to patients' age and the underlying stroke causation. MATERIALS AND METHODS: 489 patients with proven ischaemic stroke were included in this study. Subtypes of stroke were classified according to the TOAST criteria, i. e. large artery artherosclerosis (LAA), small vessel occlusion (SVO), cardioembolism (CE), stroke of other etiology (SOE), and stroke of undetermined etiology (SUE). APC-resistance was determined with a functional method with high sensitivity and specificity for the factor V Leiden mutation. The results were compared with the prevalence of APC-resistance in healthy volunteers, all born in the same area. RESULTS: APC-resistance was found in 24 of 489 patients (4.9 %) and in 6 of the 112 (5.4 %) control subjects. In the stroke patients, APC-resistance was distributed as follows: LAA 6.5 % (9/138), SVO 3,9 % (4/104), CE 6.7 % (7/104), SOE 3.6 % (1/28), SUE 2.6 % (3/115). Prevalence of APC-resistance was not significantly different between young stroke patients (6-45 years) and older patients (7.7 % [5/65] versus 4.5 % [19/424]). CONCLUSIONS: Prevalence of APC-resistance is not increased in patients with ischaemic stroke. Additionally, no significant differences in the prevalence of APC-resistance are evident within the various stroke subtypes.

Application of interphase cytogenetics for the detection of t(11;14)(q13;q32) in mantle cell lymphomas.

BACKGROUND: The chromosomal translocation t(11;14)(q13;q32) is the hallmark of mantle cell lymphoma (MCL) in which it can be detected cytogenetically in about 75% of cases. The t(11;14) translocation juxtaposes the bcl-1 locus in chromosome band 11q13 next to the IgH locus in chromosome band 14q32 and, thus, leads to deregulation of the cell cycle regulatory protein cyclin D1, which is encoded by the CCND1 gene localized at the telomeric border of the bcl-1-locus. MCL has the worst prognosis of all low-grade non-Hodgkin's lymphomas (NHL). In some instances, however, histopathologic differentiation between MCL and other low-grade B-cell NHL is difficult. Therefore, detection of the t(11;14) translocation is of essential diagnostic value for the risk-adjusted management of patients with MCL. Unfortunately, chromosome analyses are frequently hampered by the low yield and quality of tumor metaphases. As the 11q13 breakpoints are scattered over a region of more than 120 kb the application of molecular genetic techniques is also limited. PATIENTS AND METHODS: We established an interphase fluorescence in situ hybridization (FISH) approach for the detection of the t(11;14) translocation by use of a cosmid probe hybridizing to the IgH constant region and a YAC spanning the bcl-1 region. Cells containing a t(11;14) translocation show a colocalisation of the signals for IgH and bcl-1. Eight control samples and 15 MCL specimens were investigated. RESULTS: According to our control studies, samples containing more than 10% of cells with this signal constellation can be diagnosed as carrying a clonal t(11;14) translocation. All eleven MCL found to carry the t(11;14) translocation by chromosome analysis were positive in our FISH assay. Additionally, two of four MCL lacking a clonal t(11;14) translocation by chromosome analysis were shown to carry this aberration in 14% and 37% of interphase nuclei. Southern blot data indicate that our FISH assay reliably detects the t(11;14) translocation irrespective of the location of the breakpoints within the bcl-1 region. CONCLUSIONS: The described interphase FISH assay provides a reliable and routinely applicable tool for diagnosis of the t(11;14) translocation.

Detection of the t(14;18) chromosomal translocation by interphase cytogenetics with yeast-artificial-chromosome probes in follicular lymphoma and nonneoplastic lymphoproliferation.

PURPOSE: The aim of this study was to establish a fluorescence in situ hybridization (FISH) technique for the detection of t(14;18)(q32;q21), characteristic for follicular lymphoma (Kiel classification: centroblastic centrocytic [cb-cc] lymphoma). MATERIALS AND METHODS: After the FISH system had been established, parallel studies of lymph node biopsy specimens from 30 patients with cb-cc lymphoma and from 32 patients with nonneoplastic lymphoproliferation were performed by means of chromosome analysis, polymerase chain reaction (PCR), and FISH analysis. Two differently labeled yeast-artificial-chromosome (YAC) probes that contained the entire bcl-2 gene and the C-region of the immunoglobulin H (IgH) gene, respectively, were used to detect t(14;18) by FISH. RESULTS: The presence of the translocation is indicated by a red (Cy3)/green (fluorescien isothiocyanate [FITC]) double signal, which corresponds to the IgH/bcl-2 fusion gene, whereas in normal cells the signals are separate. Control studies showed that the double signal is visible in less than 1% of normal cells. FISH analysis was able to identify the t(14;18) in all cases of cb-cc lymphoma we studied. All bcl-2 breakpoints can be detected. Combined immunophenotyping and interphase cytogenetics demonstrated that t(14;18) was restricted to CD22+ B lymphocytes and never occurred in CD3+ T lymphocytes. In four of 32 cases of nonneoplastic lymphoproliferation, t(14;18) was also detected. CONCLUSION: FISH turned out to be the most sensitive method to detect t(14;18). Our FISH results confirm PCR data from other groups that found evidence for the presence of t(14;18) in nonneoplastic lymphoproliferation. It needs to be determined whether, in morphologically nonneoplastic processes, t(14;18) is associated with an increased risk for the development of non-Hodgkin's lymphoma.

Simultaneous presence of t(11;14) and a variant Burkitt's translocation in the terminal phase of a mantle cell lymphoma.

Little is known about the clinical significance of secondary chromosome aberrations in lymphomas with t(11;14)(q13;q32), the characteristic change of mantle cell lymphomas. Here we present a patient with mantle cell lymphoma, who showed a variant Burkitt's translocation t(2;8)(p12;q24) in addition to t(11;14) during the progression of the disease. An involvement of chromosome 8q24, the localization of the c-myc gene, has so far been described in only four patients, who seemed to have a fatal clinical course. Although no blastic transformation occurred in our patient, no remission could be induce by intensified treatment and survival was only 5 months. This case demonstrates that secondary chromosome aberrations can determine the clinical course of patients, even if morphologic and immunophenotypic findings fail to predict the poor outcome.

Movement-related cortical potentials in persistent mirror movements.

Mirror movements (MMs) are involuntary movements executed on one side of the body during voluntary movements of the contralateral homologous body parts which may abnormally persist into adulthood. In 6 subjects affected by persistent MM with autosomal dominant inheritance, movement-related cortical potentials (MRCPs) during self-paced, voluntary extensions of either the left or right middle finger were recorded from 30 EEG electrodes simultaneously with the electromyogram (EMG) of both extensor digitorum communis muscles. The negative potentials before and during EMG onset were evaluated statistically for the two electrodes next to the cortical hand areas. A comparison with 7 normal subjects revealed no marked differences for the Bereitschaftspotential (BP) and the negative slope (NS'). Only in the periods around EMG onset (from -50 to +50 msec) a significant difference between both groups was found. The MM subjects showed fairly symmetric potentials over the right and left hemispheres, whereas the potentials of the control subjects were lateralized to the hemisphere contralateral to the intended movement. No difference was found for the amplitude of the maximum negative peak of MRCP following EMG onset. Our data showed no evidence for a different type of movement preparation in MM subjects as compared to normals. We propose that the additional ipsilateral cortical activation around movement onset may be the cortical mechanism, which compensates for abnormal ipsilateral corticospinal pathways in subjects with persistent MM.

Clonal t(8;14)(p11;q31) in a case of reactive lymphoproliferation.

A clone with an unbalanced translocation t(8;14)(p11;q31), resulting in deletion of the distal part of the long arm of chromosome 14, 14q31 --> 14qter, was detected in a case of Piringer's lymphadenitis. Histopathologically no atypical cells or other signs of malignant lymphoma were found. Southern blot analyses showed no rearrangement of the immunoglobulin heavy chain gene (IGH) or the T-cell receptor gamma chain (TCRG) gene. The case exemplifies that the detection of a chromosomally aberrant clone does not necessarily prove that a lymphoproliferative process is malignant.

Bereitschaftspotential: is there a contribution of the supplementary motor area?

Bereitschaftspotentials (BPs) preceding simple repetitive finger movements were recorded in 11 normal volunteers. By modeling the recorded data with multiple equivalent dipoles we found that bilateral sources in the motor cortex were the best fitting hypothesis for the early BP. The activity of the source contralateral to the moving finger was increased during the steep slope of the late BP before and during the motor potential. Around and after electromyogram (EMG) onset, separate sources were detected for the motor potential close to the anterior wall of the central sulcus, and for the reafferent somatosensory potential in the postcentral gyrus. Their source wave forms showed short transient deflections peaking about 10 msec and 100 msec, respectively, after EMG onset. No evidence was found for significant source currents in the supplementary motor area (SMA), which has been suggested as the main generator of the BP. Placing probe dipoles arbitrarily into the region of the SMA did not result in the detection of a large source activity. Therefore, we conclude that the SMA does not provide a major contribution to the scalp BP during simple repetitive finger movements.

Bereitschaftspotential in idiopathic and symptomatic restless legs syndrome.

Patients with idiopathic and symptomatic restless legs syndrome (RLS) suffer from "dyskinesia while awake" or "daytime myoclonus" when at rest preceded by sensory symptoms. In order to characterise the RLS either as reflex movement or as voluntary movement we measured movement-related cortical potentials in 5 idiopathic and 8 uraemic RLS patients. Movements from both legs were polygraphically recorded concomitantly with cortical activity 2000 msec before to 500 msec after onset of EMG activity. These data were compared with a voluntary simulation of each patient's movement pattern and with 5 age-matched controls performing dorsiflexion of the right, left and both feet. Cortical activity preceding daytime myoclonus was absent in RLS patients whereas self-initiated leg movements in patients elicited onset times (1180-1380 msec) and amplitudes of Bereitschaftspotential (readiness potential) not significantly different from readiness potentials in control subjects (P > 0.05). Lack of movement-related potentials in myoclonus and/or dyskinesias during daytime in RLS patients is compatible with an involuntary mechanism of induction and points towards a subcortical or spinal origin of RLS.

The time course and location of cerebral evoked activity associated with the processing of colour stimuli in man.

Area V4 has been located in man in the region of the fusiform gyrus on the inferior surface of the occipital lobe. Using multiple dipole source analysis on multichannel EEG recordings of visual evoked potentials to coloured 'Mondrian' stimuli in man, we have confirmed that activity is consistently seen in this area regardless of the retinal area stimulated and have obtained new information concerning its time course. Three different localized centres of activity follow the visual stimulus, with peak latencies of 90, 110 and 160 ms, and arising respectively in the region of visual areas V1, V2/V3 and V4. The time course and character of the V4 dipole activity to a colourless black-and-white Mondrian is indistinguishable from that to the coloured Mondrian, supporting the evidence that the cells of V4 are not exclusively concerned with colour processing.

Identification of the visual motion area (area V5) in the human brain by dipole source analysis.

The retinal periphery of nine healthy subjects was stimulated with computer-generated random-dot kinematograms. These stimuli provided almost isolated visual motion information and minimal position cues. Pattern-reversal stimuli at the same location in the visual field were used for control. Stimulus-related electrical brain activity was recorded from 29 scalp electrodes. Total mean and individual data were analyzed with a spatiotemporal multiple dipole model. The scalp potentials showed a different spatial distribution for motion and pattern stimulation in the time range of 160-200 ms. In this epoch, the predominant motion-related source activity was localized in the region of the contralateral occipital-temporal-parietal border. A significant ipsilateral source activity was not found. The predominant source activity related to the pattern stimulus occurred in the same epoch. The corresponding equivalent dipole was localized more medially and deeper in the brain. The orientation of these major dipole activities was markedly different. These dipoles appeared to represent activity of distinct extrastriate areas, in contrast to earlier activity which was modelled by more posterior dipoles in the occipital lobe. The latter dipoles were at comparable contralateral locations and had similar peak activities around 100 ms, suggesting an origin in the striate cortex.

Transcranial magnetic stimulation (TMS) of the brain in patients with mesiotemporal epileptic foci.

Transcranial magnetic stimulation (TMS) of the human brain is mainly used for the diagnosis of diseases with disturbed central motor conduction. Recent studies revealed controversial results concerning the possibility of a TMS-induced specific activation of epileptogenic foci in patients with localization-related epilepsies, which would make TMS an additional diagnostic tool for the presurgical localization of the primary epileptogenic zone. We applied TMS to 19 patients with complex-partial seizures and investigated its effects and safety. In 12 patients we performed TMS during scalp electroencephalogram (EEG) recordings. The remaining 7 patients with localization-related epilepsies of mesiobasal limbic seizure origin underwent EEG with additionally implanted foramen-ovale-electrodes (FOE). We did not notice any significant spike activation and even observed bilateral reduction of epileptic activity in some patients. On the contrary, hyperventilation induced a marked activation of the epileptic focus. Our findings support that TMS is safe since adverse effects did not occur. However, due to possible safety hazards, TMS in epileptic patients still requires cautious application until more data will be available.

[Gustatory sweating demonstrated by infrared thermography]. / Gustatorisches Schwitzen. Nachweis mit Infrarot-Thermographie.

A 35-year-old man, previously healthy except for a grade 1 goitre, sustained a spontaneous left pneumothorax treated with a Bülau drain. When the left pneumothorax recurred 2 months later a left thoracotomy was performed. Two bullae at the lung apex were resected and a pleurodesis performed. After the operation the patient noted hypaesthesia of the dorsum of the left upper arm, mild ptosis of the left eyelid as well as reduced sweat secretion over the left half of the face and the left rib cage. The hypaesthesia improved, but the sympathetic nerve deficits remained. There were no other neurological signs. 9 months later, within one minute of eating a sour apple, the patient developed severe sweating over the left half of the face and the left chest. The reaction was confirmed by infra-red thermography which proved that the skin temperature in the sweating region had fallen to 3 degrees C. The likely cause of localized gustatory sweating is intra-operative damage of the stellate ganglion or its preganglionic nerve connections. Treatment is limited to avoidance of the precipitating gustatory stimulus.

Isoelectric focusing pattern of human amniotic fluid alpha-fetoprotein.

Isoelectric focusing (IEF) of amniotic fluid alpha-fetoprotein (AFP) in thin-layer polyacrylamide gels containing 8 M urea followed by immunoblotting reveals at least nine bands, band I lying next to the cathode. Compared with 298 amniotic fluid samples from normal pregnancies, we found that the density of band V was increased in seven cases of fetal death. In 16 amniotic fluid samples from pregnancies with open neural tube defects (ONTD), band V disappeared or was markedly decreased. In seven cases with elevated AFP and positive acetylcholinesterase (AChE) due to contamination with fetal blood, no difference in pattern was observed compared with samples from normal pregnancies. It is suggested that IEF of AFP and subsequent immunoblotting are an apparently diagnostic test for ONTD and intrauterine fetal death (IUFD).