Results of parenchymal and angiographic magnetic resonance imaging and neuropsychological testing of children after stroke as neonates

We describe the long-term follow up of infants after neonatal stroke of the middle cerebral artery (MCA). Stroke was diagnosed by CT scan in eight full-term neonates. Three dimensional (volume) magnetic resonance angiography (MRA) is a noninvasive technique that images the arterial vessels without contrast agents. All patients, aged from 1.5 to 8.4 years, were investigated by MRI and MRA and by neuropsychological tests. Cognitive development was investigated by intelligence tests, tests of visual perception, motor and language development. Out of the eight patients, seven had a retarded mental and motor development, and 50% of the children were treated for epilepsy. Seven patients had a spastic hemiparesis. Seven out of eight children showed major cognitive deficits. In all patients, MRI revealed clear parenchymal defects with variable distribution patterns. MRA studies showed abnormalities corresponding to the expected vascular distribution. Children with complications at delivery, with seizures, and an interruption of the main stem of MCA as demonstrated on MRA had the least favourable long-term follow up prognosis with severe cognitive delays.

Effects of metal ions, thiamine diphosphate analogues and subunit interactions on the reconstitution behaviour of pyruvate decarboxylase from brewer's yeast

The reconstitution of pyruvate decarboxylase starts with reversible binding of thiamine diphosphate and Mg2(+)-ions to the apoenzyme, followed by a rate-limiting conformational change to the catalytically active holoenzyme. Investigations with diphospho-esters of 4-methyl-5-(2-hydroxyethyl)thiazolium derivatives have shown that the diphosphate residue of thiamine diphosphate is the most important part of the coenzyme responsible for the first reversible binding step. Methylation of the N1'-atom of the pyrimidine ring of thiamine diphosphate or 4'-oxythiamine diphosphate prevents the coenzyme from binding stably to the apoenzyme, so that the methylated coenzyme displays no coenzyme activity. In contrast, thiamine diphosphate analogues with bulky residues on the neighbouring C2'-atom of the pyrimidine ring form active holoenzyme complexes. This result shows the essential role of the N1'-atom of thiamine diphosphate in stable cofactor binding. The cofactor binding rate to the dimeric and tetrameric apoenzymes indicates that the cofactor is located in the contact regions of the subunits in the tetrameric enzyme.

The influence of the effectors of yeast pyruvate decarboxylase (PDC) on the conformation of the dimers and tetramers and their pH-dependent equilibrium

The influence of effectors of yeast pyruvate decarboxylase, phosphate, pyruvamide, thiamin diphosphate and Mg++, on the pH-dependent equilibrium between dimers and tetramers was studied by synchrotron radiation X-ray solution scattering. Thiamin diphosphate and phosphate shift the equilibrium to higher pH values without altering the structure of the oligomers. Pyruvamide, a substrate analogue activator, induces a significant change in the structure of the tetramer. By eliminating radiation damage by addition of dithioerythrol to the buffers, the scattering curves could be measured accurately over a large angular range. They were expanded in terms of spherical harmonics to obtain the shapes of the dimers and tetramers with higher resolution than was hitherto possible. This also allowed us to position the dimers, which are centrosymmetric at low resolution, in the tetramers which have 222 symmetry. The results indicate that addition of pyruvamide results in a less compact tetramer owing to structural changes in the dimers and to their displacements.

[Stored intracardiac electrograms: accuracy of arrhythmia classification in patients with cardioverter/defibrillator system]

A cardioverter/defibrillator that is capable of storing endocardial electrograms before and after electrical device therapy was implanted in 29 patients presenting drug refractory ventricular arrhythmias. During a follow-up period of 7.5 +/- 4.6 months 15/29 patients (51%) experienced a total number of 112 pulse generator discharges. In 104 arrhythmia episodes the stored electrogram was analyzed. Morphological criterias of the stored electrogram as detectable P-waves and changes in the QRS-morphology during tachycardia compared to sinus rhythm served for classification of the documented arrhythmia. The analysis of the stored electrogram established a definitive diagnosis of the arrhythmia and allows to distinguish supraventricular arrhythmias from ventricular arrhythmias in every episode. 72/104 (69.2%) of the discharges were classified as appropriate, 32/104 (30.8%) of the device discharges were not appropriate and caused by atrial fibrillation and flutter, sinustachycardia and AV-nodal reentrant tachycardia. In two patients device discharges caused by a sensing malfunction ot the pulse generator was detected by the analysis of the stored electrogram. The new diagnostic feature of stored electrogram shows a high accuracy of rhythm classification and represents a major advance in the treatment with cardioverter/defibrillators.

Immunological detection of proteins associated with the Epstein-Barr virus nuclear antigen 2A

The Epstein-Barr virus nuclear antigen 2A (EBNA-2A) has been strongly implicated in the EBV-mediated B-cell transformation process. Since EBNA-2A might exert this function through interaction with proteins of the infected cell, we studied the association of EBNA-2A with cellular proteins. Immunoprecipitation of EBNA-2A from 32P-labeled cell extracts separated by sucrose gradient centrifugation revealed the presence of phosphoproteins complexed with the two forms of the EBNA-2A sedimenting at 13 S and 34 S. Prominent bands were observed at 250, 170, 120, 110, 105, and 95 kDa with minor species at 78, 52, 45, 31, 26, 22 and 18 kDa. By "West-Western" or "Far-Western" blotting using EBNA-2A protein from insect cells as a probe we detected binding to proteins migrating with apparent molecular masses of about 200, 130, 110, 105, 95, and 31 kDa with minor species detectable at 90, 68, 50-55, 40, and 17 kDa. The protein with an apparent molecular mass of 31 kDa was identified by competition experiments as histone H1. Some of the EBNA-2A-complexed phosphoproteins, notably the proteins of 110 and 95 kDa, comigrated with the proteins detectable by "West-Western" analysis. The binding of EBNA-2A to the 130-kDa protein was stable against up to 1.5 M NaCl and could not be competed with histone H1. In a similar experiment, the less transforming EBNA-2B which is encoded by the subtype 2 virus bound to most of the proteins detected with EBNA-2A but with strongly reduced efficiency to the protein of 130 kDa indicating that this protein might be a target for EBNA-2 during EBV-mediated transformation.

[Ultrasound study of the elbow joint in patients with chronic inflammatory joint diseases--an enrichment of diagnosis?]

After clinical and radiological examination, the elbows of 74 patients with rheumatoid arthritis were examined by ultrasound. Clinical examination gives a good impression of the inflammatory changes of the elbow joint. Sonography was very useful in detecting synovitis and joint effusion and their distribution in the different parts of the joint. It is a good method to document the therapeutic effects; therefore, beside the clinical and radiological findings ultrasound may be helpful in planning further therapeutic measures for the patient.

[Ultrasound in inflammatory rheumatic joint diseases]

Inflammatory changes of the shoulder joint could be detected at a very early stage, when the clinical and radiological examinations were unremarkable. In 50% of the cases a rupture of the rotator cuff could be demonstrated. Only 10% of the shoulder joints had normal sonographic findings, whereas 50% were normal on clinical or radiological examination. Synovitis and effusion of the hand can be diagnosed very well by clinical examination, and can be documented in ultrasound. The sonographic diagnostic accuracy in tendon ruptures of the hand is lower than accuracy of the clinical examination. New technical developments may yield better results. Inflammatory changes of the hip joint are very difficult to diagnose by clinical examination. Synovitis, effusion and changes of the capsule can be better detected by ultrasound. Sonography of the hip joint has become part of our routine diagnostic programme, especially because early changes of the joint do not present clear symptoms.

Correlation of cofactor binding and the quaternary structure of pyruvate decarboxylase as revealed by 31P NMR spectroscopy

The pH dependence of the quaternary structure of pyruvate decarboxylase (EC 4.1.1.1) has recently been discovered [(1990) FEBS Lett. 266, 17-20; (1992) Biochemistry (in press)]. In the present study we have investigated the change in quaternary structure by observing the binding of the cofactor, thiamine pyrophosphate, using 31P NMR spectroscopy. The dissociation of the native tetramers into dimers when increasing the pH coincides with a weaker binding of the cofactor and loss of enzyme activity. The results provide further evidence that thiamine pyrophosphate is bound primarily via the beta-phosphate moiety. In addition, a phosphoserine has been discovered in two of the four subunits.

Synchrotron radiation solution X-ray scattering study of the pH dependence of the quaternary structure of yeast pyruvate decarboxylase

The pH dependence of the quaternary structure of pyruvate decarboxylase from yeast was studied in the range 6.2 less than pH less than 8.4. There is an equilibrium with a midpoint around pH 7.5 between tetramers and dimers, and the catalytic activity of the enzyme depends on the volume fraction of tetramer. This equilibrium may provide an additional regulating mechanism besides substrate activation since accumulation of pyruvate would lead to a reduction in pH and hence an increase of the concentration of the catalytically active tetramer. Radiation damage during the X-ray scattering experiments results in a shift of this equilibrium and in the formation of octamers. These effects could be circumvented and analyzed using experimental and data processing methods which can be readily applied to other radiation-sensitive systems. The low-resolution shapes of the dimers and tetramers were determined from the scattering curves using spherical harmonics. The results indicate that a conformational change must occur in the dimers upon formation of the tetramers, in agreement with earlier circular dichroism measurements.

A novel platelet-derived renal vasoconstrictor agent in normotensives and essential hypertensives

Platelet homogenates from 200 ml blood of essential hypertensives (n = 28) and normotensives (n = 13) were deproteinized and separated by gel chromatography. The fractions obtained were then tested for vasopressor activity in the isolated perfused rat kidney. In both normotensives and hypertensives, two vasopressor fractions appeared. There was no difference in vasopressor activity in the first vasoactive fraction between normotensives and hypertensives. In the second vasoactive fraction, the hypertensive patients showed a significant higher activity than the normotensive subjects (increase in perfusion pressure by 35.9 +/- 11.5 vs. 6.8 +/- 5.3 mmHg, p less than 0.01). This vasopressor fraction was not inhibited by saralasin, phentolamine, ketanserin, nitroprusside and daltroban and was effective after pretreatment with indomethacin and reserpine and in enzymatically deendothelialized kidneys. The effect was reduced by nifedipine and unchanged by heating the fraction at 100 degrees C and by incubation with proteinase K. It is concluded that a yet unidentified platelet-derived vasopressor agent may contribute to the enhanced vasoconstriction in essential hypertension.

Phosphorylation of SV40 large T antigen at threonine residues results in conversion to a lower apparent molecular weight form

Simian virus 40 large T antigen (large T) was dephosphorylated with potato acid phosphatase at pH 5.5. Phosphate residues bound to serine were more susceptible to potato acid phosphatase than threonine-bound phosphate residues. Dephosphorylation of the threonine residues with potato acid phosphatase resulted in a reduced gel-electrophoretic mobility, while removal of the remaining phosphate groups had no effect on the mobility of large T. Pulse-chase experiments revealed a slower migrating form of newly synthesized large T which was converted by phosphorylation to a faster migrating form and had a half-life of approximately 1 h.

Inhibition of cardiac sympathetic nerve activity during swallowing evoked by laryngeal afferent stimulation in the cat

Spontaneous swallowing or the buccopharyngeal phase of swallowing evoked by electrical stimulation of the superior laryngeal nerve was accompanied by a pronounced decrease of sympathetic activity in the cardiac nerve. This reduction of sympathetic activity was not related to other influences such as postinspiratory inhibition or baroreceptor-mediated inhibition. Intracellular recordings from sympathetic preganglionic neurones revealed hyperpolarization during the buccopharyngeal phase of swallowing, possibly due to postsynaptic inhibition.

Chemosensitivity of sympathoexcitatory neurones in the rostroventrolateral medulla of the cat

The hypothesis that sympathoexcitatory neurones within the rostroventrolateral medulla (RVLM) may be chemosensitive was tested in chloralose-anaesthetized cats by artificial perfusion of the RVLM via the left vertebral artery. The baroreceptors and peripheral chemoreceptors were denervated by bilaterally dissecting the carotid sinus and vagus nerves. Either white ramus T3 (WR-T3) or the renal nerve was recorded to monitor sympathetic activity. Perfusion with saline or Ringer solution bubbled with CO2 (10%-100%) produced a rapid and pronounced increase in sympathetic activity and blood pressure. Solutions adjusted to the same pH (pH 5.2 for 100% CO2) with HCl resulted in a much weaker excitation. A linear relationship between PCO2 and sympathetic activity was demonstrated. During prolonged perfusion (90 s) sympathetic activity returned to the control level after initial excitation and fell below control levels when perfusion ceased. The sympathetic activity response to CO2-bubbled solutions was unaffected by blockade of synaptic input by microinjection of CoCl2 into the RVLM, whereas spontaneous sympathetic activity and the supraspinal somato-sympathetic reflex from intercostal nerve T4 to WR-T3 were markedly reduced. It is therefore concluded that sympathoexcitatory bulbospinal neurones in the RVLM are directly chemosensitive to changes in arterial PCO2 and pH.

Follow-up of antibiotically treated and untreated neuroborreliosis

Follow-up of 57 patients who suffered from antibiotically untreated acute, monophasic neuroborreliosis 5 to 27 years ago shows no significant difference in comparison with the follow-up of 66 patients who suffered from antibiotically treated acute, monophasic neuroborreliosis during the last 5 years. In both groups, the involution of clinical symptoms and the normalization of pathological CSF findings were nearly identical. We found no significant difference of sequelae between the groups. Following acute neuroborreliosis, neither the antibiotically untreated nor the antibiotically treated patients developed chronic neuroborreliosis. Only in rare cases of primary chronic neuroborreliosis with CNS involvement did we observe convincing effects of antibiotics, which were given mostly in combination with glucocorticosteroids.

An X-ray solution scattering study of the cofactor and activator induced structural changes in yeast pyruvate decarboxylase (PDC)

Structure and activation pattern of pyruvate decarboxylase (PDC) from yeast was studied by synchrotron radiation X-ray solution scattering. The results give a direct proof that the reversible deactivation of PDC at pH 8.0 is accompanied by the dissociation of the tetrameric holoenzyme into dimeric halves. The kinetics of this process was followed. At pH 6.5 the dimeric halves reassociate to a tetramer even in the absence of cofactors. The changes of the scattering pattern upon binding of the substrate-like activator pyruvamide indicate that the structure expands in the course of the enzyme activation.

[Results of plate osteosynthesis in comminuted fracture of the olecranon]

Comminuted fractures of the olecranon are an absolute indication for operative treatment. Adequate therapy is only possible when open reduction and plating are performed. In the last 20 years, 31 of our patients, i.e. 0.0001% of all patients treated for injuries, had this type of olecranon fracture, and in 25 follow-up examination was possible. The fracture type was classified according to the ASIF system. The range of motion, i.e., extension, flexion, pro- and supination, and pain, physical strength and rehabilitation were classified according to our own system. In cases with concomitant fracture of the radial head, reconstruction is necessary to provide adequate axial movement and strength in the forearm. Brief plaster fixation after the operation makes it possible to restrict the development of ankylosis in the elbow joint. The results were excellent in 10 patients, good in 5 patients, fair in 4 and poor in 6 patients. In 3 patients, i.e. 10% ankylosis was present in the elbow joint; this was considered to constitute an indication for arthroplasty, which gave a better postoperative range of motion.

[Function of the right ventricle in patients with mitral valve diseases]

To investigate right ventricular function in mitral valve disease, biplane cineventriculograms of the right and left ventricle were performed in 96 patients-35 with mitral stenosis, 26 with mitral regurgitation, 12 with combined mitral valve disease, 14 with mitral stenosis and tricuspid regurgitation, and nine with mitral regurgitation and tricuspid regurgitation, compared to 18 normals (N). Right ventricular enddiastolic volume index was moderately elevated in patients with mitral stenosis and concomitant tricuspid regurgitation (111.6 +/- 35.3 ml/m2, no significance compared to N: 95.9 +/- 21.8 ml/m2) and with mitral regurgitation and tricuspid regurgitation (107.9 +/- 45.1 ml/m2, no significance compared to N). A reduced right ventricular ejection fraction (RVEF less than or equal to 50%) was found in 40 of the 96 patients. Right ventricular ejection fraction was frequently reduced in patients with mitral regurgitation and tricuspid regurgitation (46.7% +/- 15.1%) and significantly reduced in patients with combined mitral valve disease (45.0 +/- 17.6%, compared to N: 58.0 +/- 7.1%, p less than 0.01). No significant correlations were found between right ventricular ejection fraction and left ventricular enddiastolic volume or left ventricular ejection fraction in patients with mitral valve disease. Moreover, right ventricular ejection fraction did not correlate with systolic pulmonary artery pressure, mean pulmonary artery pressure or mean pulmonary capillary wedge pressure. Local wall motion (mean systolic shortening) was determined for the anterior, anteroapical, and inferior segment in the RAO-projection and for the right ventricular free wall in the LAO-projection. 63% of the patients (n = 25) with reduced right ventricular function (RVEF less than of equal to 50%) showed local wall motion abnormalities, preferably in the anterior segment of the RAO- projection (48%) and the right ventricular free wall (30%).(ABSTRACT TRUNCATED AT 250 WORDS)

Fatal liver failure in 16 children with valproate therapy

The data of 16 children who died while receiving valproate (VPA) therapy in West Germany were analyzed. Five were normally developed, 5 were receiving VPA-monotherapy, and only 2 patients were aged less than 3 years. The first clinical symptoms of impending hepatotoxicity usually included nausea, vomiting, and apathy; pathologic laboratory tests reflected liver failure. Liver histology revealed microvesicular steatosis, cell necrosis, and bile duct proliferation of varying degree. An abnormal metabolite, 4-ene-VPA, was detected in all examined patients (six of six) and persisted after drug withdrawal. The pathogenesis of fatal liver failure during VPA treatment remains unknown. World-wide, approximately 100 fatalities have been reported in relation to VPA treatment. More than 90% were aged less than 20 years, 95% developed their first symptoms within the first 6 months of treatment, and 16 were treated with VPA alone. Since it is difficult precisely to define a group at risk for fatalities with VPA, careful clinical and laboratory monitoring with a special focus on vomiting and apathy, liver enzymes, and coagulation tests seem mandatory during the first 6 months after introduction of VPA. Taking into account the considerable number of fatalities during VPA treatment, the indication for its use requires careful reevaluation.