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R Lahl

Publications and source records attributed to R Lahl.

At least 19 recordsLinked to original sources
PubMed2003

Stimulus-induced patterns of bioelectric activity in human neocortical tissue recorded by a voltage sensitive dye.

Stimulus-induced pattern of bioelectric activity in human neocortical tissue was investigated by use of the voltage sensitive dye RH795 and a fast optical recording system. During control conditions stimulation of layer I evoked activity predominantly in supragranular layers showing a spatial extent of up to 3000 microm along layer III. Stimulation in white matter evoked distinct activity in infragranular layers with a spatial extent of up to 3000 microm measured along layer V. The mean amplitude of optical signals close to the stimulated sites in layer I and white matter determined 25 ms following the stimulus, decreased by 50% at a lateral distance of approximately 900 microm and 1200 microm, respectively. Velocity of spread along the vertical stimulation axis reached 0.24 m/s in the supragranular layers (layers I to III) and then decreased to 0.09 m/s following layer I activation; stimulation of white matter induced a velocity of spread in layer V of 0.38 m/s, which slowed down to 0.12 m/s when passing the lower border of lamina IV. The horizontal velocities of spread determined from the stimulation site to a lateral distance of 500 microm reached 0.26-0.28 m/s and 0.28-0.35 m/s for layer I and white matter stimulation, respectively. At larger distances velocity of spread decreased. Increased excitability (Mg(2+)-free solution) had no significant effect on the spatio-temporal distribution of evoked activity as compared with control conditions. There were also no obvious differences between the results obtained in slices, which generated spontaneously sharp waves and those which were not spontaneously active. About 30% of the slices (n=7) displayed a greatly different response pattern, which seemed not to be related in a simple way to the stimulation as was the case in the majority of the investigated slices. The activity pattern of those slices appeared atypical in regard to their deviations of the vertical and horizontal extent of activity, to their reduced spatial extent of activity during increased excitability, to their layer-related distribution of activity, and to the appearance of afterdischarges.Concluding, in 30% of the human temporal lobe slices atypical activity pattern occurred which obviously reflect intrinsic epileptiform properties of the resected tissue. The majority of slices showed stereotyped activity pattern without evidence for increased excitability.

Adolescent↗
PubMed2003

MRI and EEG findings in surgically treated patients with partial seizures due to neuronal migration disorders, their relations to each other and to surgery outcome.

OBJECTIVES: To evaluate magnetic resonance imaging (MRI) and electro-encephalogram (EEG) findings of patients with therapy-resistant partial seizures due to neuronal migration disorders (NMD), and compare them with each other and with surgery outcome. MATERIAL AND METHODS: The MRI, interictal and ictal EEG findings, and their relations to each other in 41 patients with NMD were compared with class IA surgery outcome. RESULTS: The patients showed an MRI lesion in decreasing frequency from the frontal to the occipital areas. A predominantly extratemporal location of the interictal EEG foci (73.3%) and ictal patterns (82.4%) was therefore apparent, also showing a diminishing frequency from the anterior to the posterior areas. Comparing the EEG foci with the MRI lesions, the same location of the interictal foci was found in 68.4% and of the ictal foci in 52.7%, including several cases with a more widespread EEG focus or MRI lesion. The same location of interictal as well as ictal foci was evident in 85.7%. The most favourable surgery outcome (class IA) was, on average, apparent in patients with an MRI lesion (28.6% vs 25%), a main interictal EEG focus (50% vs 18%) and an ictal seizure pattern (37.5% vs 16.7%) located in the temporal area; likewise, if the interictal focus (30.8% vs 18.2%) and the ictal pattern (31.8% vs 12.5%) showed the same location as the MRI lesion, as well as when the interictal and ictal EEG changes had an equal location (30% vs 20%). CONCLUSION: MRI and EEG recordings show relatively close relations to each other and might be important methods to predict surgery outcome in NMD patients.

Adolescent↗
PubMed1998

Flat and steep terminal negativity in the DC-potential after deprivation of oxygen and glucose in human neocortical slices.

The so-called terminal negativity (TN) of the DC-potential is a characteristic reaction of neuronal tissue to hypoxia or ischemia. In a previous study on human neocortical slices, two types of TN with flat and steep slopes of rise (< or >10 mV/min) were found with hypoxia. The aim of the present study was to further investigate causes underlying the occurrence of flat and steep TN. Experiments were performed on 23 human neocortical slices (500 micron) resected from 13 patients (epilepsy and tumour surgery). DC-potential and evoked potentials (white matter stimulation) were recorded in layer III. The extracellular potassium concentration ([K+]o) was measured by K+-sensitive microelectrodes. In an interface type chamber, ischemic episodes were induced by oxygen and glucose deprivation. They were terminated when TN had peaked. Both flat and steep TN also existed with ischemic conditions. There was a linear correlation between the slope of rise of TN and the associated slope of rise in [K+]o, respectively, but none regarding latencies of TN or recovery of evoked potentials. Peak levels in [K+]o were 13.9+/-0.9 mmol/l. Compared to control, the slope of rise and latency of TN were clearly increased by addition of dimethyl sulfoxide (DMSO, 0.4%) to the bath solution, whereas nimodipine (40 micromol/l) in 0.4% DMSO had neither an effect on slope of rise of TN nor on latency of TN. As a whole, our observations suggest, that the actual metabolic state determines the occurrence of flat or steep TN.

Brain Ischemia↗
PubMed1997

Secretory meningioma: clinical, histologic, and immunohistochemical findings in 31 cases.

BACKGROUND: Secretory meningioma is a rare histologic variant characterized by a unique epithelial differentiation of meningothelial cells resulting in the production of hyaline inclusions. Most previous reports have presented single case observations. The authors selected 31 cases for a clinicopathologic study to characterize this type of tumor further. METHODS: Clinical data were compiled and the extent of peritumoral edema was assessed from preoperative computed tomography or magnetic resonance imaging scans. Preparations of surgical specimens of all tumors were studied after both conventional histologic and immunohistochemical preparations were made. Immunostaining was performed by either the avidin-biotin complex method or the alkaline phosphatase-antialkaline phosphatase method using 22 primary antibodies. RESULTS: In the tumor collection used in this study, secretory meningiomas represented 3% of meningiomas. The female-to-male ratio was 9:1. Most tumors were located at the sphenoid ridge or at the frontal convexity, and recurrences were not observed. Eighty-four percent of tumors presented with slight to marked peritumoral edema. The MIB-1 staining index showed a mean of 3.8%. Inclusions and surrounding cells consistently expressed epithelial membrane antigen, cytokeratins, carcinoembryonic antigen, and carbohydrate antigen 19-9. In decreasing frequency, they also contained alpha1-antitrypsin, immunoglobulin (Ig)A, alpha1-antichymotrypsin, IgM, and IgG. Cells positive for vimentin and S-100 did not contain inclusions. All tumors were positive for progesterone receptors. Macrophages were stained with antibodies to factor XIIIa, human leukocyte antigen-DR, and alpha1-antitrypsin. In 64% of cases, tumor vessels lacked expression of glucose transporter protein 1. CONCLUSIONS: The classification of secretory meningioma as a distinct variant has been justified on clinical, histologic, and immunohistochemical grounds. The unique epithelial features call attention to the broad spectrum of differentiation properties found in meningiomas.

Adult↗
PubMed1996

Anoxic terminal negative DC-shift in human neocortical slices in vitro.

In animal models, the hallmark of a hypoxic condition is a strong negative shift of the DC potential (anoxic terminal negativity, ATN). This DC-shift is interpreted to be primarily due to a breakdown of the membrane potential of neurons. Such massive neuronal depolarizations have not been reported for all human neocortical neurons in vitro even during prolonged hypoxic periods. This poses the question whether ATN develop also in human neocortical slices made hypoxic. ATN could be observed when human brain slice preparations (n = 15, 13 patients) were subjected to periods of hypoxia (10 to 120 min). These ATN were usually monophasic and appeared with a latency of 16 +/- 4 min (mean +/- S.E.M.). Separating the ATN according to their slopes of rise, steep (> 10 mV/min) and flat (< 10 mV/min) ATN could be distinguished. Steep and flat ATN may be regarded as two different entities of reactions since steep ATN had also greater amplitudes and slopes of decay as compared a flat ATN. With repetitive hypoxias, the latency of both the steep and flat ATN was reduced for the following hypoxic episodes. During hypoxic DC-shifts, evoked potentials were suppressed. With the 1st through 4th hypoxia, they recovered fully within 30 min after reoxygenation when hypoxia was terminated at the plateau of ATN; with extension of hypoxia, recovery was only partial. From the 5th hypoxia onwards, recovery usually did not take place or was not complete.

Adolescent↗
PubMed1996

Lack of influence of histopathological changes on carbamazepine and carbamazepine-10, 11-epoxide concentrations in the brain cortex of epileptic patients.

Post-mortem concentrations of carbamazepine (CBZ) and its anticonvulsive metabolite carbamazepine-10,11-epoxide (CE) were determined in different lesions of the cerebral cortex and in the serum (total and free) from 13 epileptic patients. Twenty cortical specimens were obtained from the superior frontal gyrus, the temporopolar region and the neocerebellum. The cortical samples showed various pathological changes characterized by augmented glial cells, fibre gliosis or ulegyria as well as abundant corpora amylacea or encephalitic signs of viral type besides neuronal depletion. The CBZ and CE concentrations in the 20 cortical lesions were not significantly decreased when compared to the control specimens of 32 epileptic patients without essential histopathological alterations of the specified cortical areas (p < 0.05). A comparable result had been found in our former study on phenytoin (PHT) and phenobarbital (PB). Six patients with cortical lesions of the present series had already been included in this PHT/PB study. Five of these patients revealed unchanged CBZ and CE as well as PHT and PB concentrations. Only in one neocerebellar specimen the CE concentration was just above the upper 95% confidence limit of the control group. But, most probably this finding has no further relevance. The results greatly favour the nonspecific binding of CBZ and CE to cerebral tissue constituents.

Adult↗
PubMed1996

Relationship between ischemic damage and concentrations of phenytoin and phenobarbital in the brain cortex of epileptic patients in vegetative state at death.

Post-mortem concentrations of phenytoin (PHT) and phenobarbital (PB) were determined by high-performance liquid chromatography in the cortical matter of specified brain regions and in the serum (total and free) from 3 epileptic males in vegetative state and compared to the data of 45 deceased epileptic control patients. The duration of the vegetative state was 12 days, 15 days or about 4 months until death and was associated with corresponding stages of generalized ischemic brain damage. The histological examination was completed by immunohistochemical and morphometric methods. According to other investigators nerve cells are the major binding sites for PHT and PB in the cerebral cortex of rodents. But, in the 3 comatose patients the PHT and PB concentrations of the isocortex and neocerebellum were not significantly decreased in comparison with the control patients despite necrosis and loss of neurons as well as other distinct tissue alterations. The results strongly favor the non-specific binding of PHT and PB to cells and subcellular structures of the brain-mainly based on simple physico-chemical principles.

Adult↗
PubMed1995

Lack of effect of histological lesions on the phenytoin and phenobarbital concentrations in the brain cortex of epileptic patients.

Postmortem concentrations of phenytoin (PHT) and phenobarbital (PB) were determined in 24 specimens of the frontal, temporal, occipital or neocerebellar cortex with different pathological changes and in the serum (total and free) from 11 epileptic patients. The cortical lesions were characterized by various degrees of neuronal loss or necrosis associated with other changes such as proliferated gliocytes, fibre gliosis, Rosenthal fibres or numerous corpora amylacea. According to other investigators neurons are the main binding sites of PHT and PB in rodent brains. The PHT and PB concentrations in 20 cortical lesions from nine patients were not significantly reduced as compared to the data of 46 deceased epileptic control patients. A significantly decreased PB value could only be demonstrated in the temporal specimen of an old scarred infarction with complete demyelination. On the other hand a slight but significant increase of PB was observed in three neocortical samples from a child exhibiting severe brain oedema and thrombosis of the sinuses. The results favour the unspecific binding of PHT and PB to cerebral tissue constituents and do not support the hypothesis of major binding to specific receptors.

Aged↗
PubMed1994

Dynamic changes of focal hypometabolism in relation to epileptic activity.

The interictal hypometabolism in patients with focal epilepsy is usually regarded as stationary. In this study we investigated to which extent the hypometabolism may depend on the activity of the epileptic focus. In focal penicillin-induced epilepsy in rats the epileptic focus is hypermetabolic. This focus is accompanied by hypometabolism in widespread areas of adjacent cerebral cortex. The experiments revealed that these metabolic alterations are transient. Data from a patient experiencing a focal seizure during PET scanning gave similar results. They showed that the transition from interictal to ictal activity was accompanied by the development of hypermetabolic epileptic focus and the dynamic enlargement of the surrounding hypometabolism. Both, the experimental and clinical data provide evidence that the cerebral hypometabolism may vary in size depending on the activity of the epileptic focus. It is hypothesized that in human PET studies the large interictal hypometabolism may prevent the identification of hyperactive interictal epileptic foci due to the partial volume effects resulting from the limited spatial resolution of PET cameras.

Animals↗
PubMed1994

Concentrations of carbamazepine and carbamazepine-10, 11-epoxide in serum, brain tumors and paratumorous cortex: a prospective study of 37 neurosurgically treated epileptic patients.

Concentrations of carbamazepine (CBZ) and its metabolite carbamazepine-10, 11-epoxide (CE) were determined in serum (free and total), brain tumors and paratumorous cortex from 37 epileptic patients. Tumor biopsies were available from 25 different gliomas, 5 hamartomas and 1 angioma. The free serum concentrations of CBZ and CE were highly correlated with the corresponding paratumorous concentrations (r = 0.94 and r = 0.93) and to a lower extent with the tumorous concentrations (r = 0.78 and r = 0.75). For CBZ the concentration ratios paratumorous cortex/serum free and tumor/serum free showed no significant differences between CBZ-resistant and -nonresistant patients. Apart from histological grade a significant influence of type and site of the tumors on their CBZ and CE concentration was not recognizable. The results indicate that resistance to CBZ therapy cannot be sufficiently explained by decreased paratumorous or tumorous levels of CBZ and CE.

Adolescent↗
PubMed1986

[Diagnostic significance of computerized tomography in cerebral manifestations caused by Whipple's disease].

A woman, who died at the age of sixty, showed different clinical symptoms for more than 3 years. The disease was characterized especially by neurologic and psychical symptoms and kachexia. By autopsy a cerebral manifestation of Whipple's disease was found. The difficulties in diagnosing the main central nervous disturbances were discussed. Besides the detection of SPC-cells in the CSF and in bioptical obtained brain tissue the diagnostical importance of CT-findings increases more and more. The hitherto known and in the special literature published changes of cranial CT in Whipple's disease were reported. In the present case the cranial CT was normal.

Atrophy↗
PubMed1985

[CNS involvement in primary angiitis--personal clinicomorphologic studies of 6 cases].

We report on the clinical symptomatology, diagnostic difficulty and inadequate possibilities for treatment of 6 patients suffering from primary agiitis of intracranial vessels. They died at age 36 to 64 years. The duration of the disease varied between 6 weeks and 11 1/2 years and was diagnosed, autoptically in all cases, as giant cell angiitis (2 cases) and, trombangiitis obliterans (4 cases). A degenerative cerebrovascular process had already been assumed clinically in four of the cases, and intracranial veins were also involved in three (very distinctly in one). The vascular disease was generalised or multilocular in four observations. Although autoimmunological processes were probably involved, the etiopathogenesis is still, in the final analysis, more or less unknown.

Adult↗
PubMed1985

[Complications following myelography with positive contrast media (Pantopaque, Amipaque). Pathomorphologic findings in 2 fatal cases].

It is reported on three patients which suffered from severe side effects after cervical myelography using Amipaque (cases 1 and 3) and Pantopaque (case 2). In 2 cases death occurred after 13 days (case 2) respectively 17 days (case 3). Worsening of the clinical symptoms appeared in all cases within four days after myelography. In the first 2 cases inflammatory alterations prevailed whereas in the third case complications probably based on mechanical irritations of nerval and vascular structures. In the 2 lethal cases autopsy offered a prostatic cancer with vertebral and intraspinal metastases respectively syringobulbia and cervical syringomyelia beside an ependymoma of the cervical spinal cord as incurrable complaints. The various side effects and complications after myelography using positive contrast media as well as their causes are discussed.

Aged↗
PubMed1984

[Clinical manifestation of thrombendangiitis obliterans of the central nervous system].

It is reported on the clinical and morphological findings of two women with obliterating thrombendangiitis who finally died of the sequelae of this vascular disease at the age of 36 years and 64 years, respectively, after a 14-year and 10-month duration of the disease. Despite generalisation or multilocalisation of the disease only the cerebral symptomatology was clinically manifest. The diagnosis obliterating thrombendangiitis could be verified only by histological investigations post mortem. In the second case intracranially exclusively a venous affection of the vessels of the cerebral sinuses, of ascending veins of the cerebral covering and profound cerebral veins with differently old inflammation foci in the sense of an obliterating thrombendangiitis was present. It is referred to the general problems of diagnosis, etiopathogenesis and therapy of the obliterating thrombendangiitis.

Adult↗
PubMed1984

[Psychological and sexual effects of hormonal contraceptives--results of a survey].

Subject of our examination are emotional-affective, vegetative and psycho-sexual disturbances which are possibly caused by oral contraceptives. 511 women, taking different oral contraceptives, were questioned. For that purpose we used a schedule of sociological dates, attitudes and complaints devised by ourself and connected with a part of Böttcher's Introversion-Neurotizism-Rigidity-Questionnaire. Neurotic and introverted persons are tending to suppose a connection between the "Pill" and certain inconvenient sensations as affective disturbances, diminished concentration, dyssomnia and an avoidance behavior in sexuality. But the results of investigation gave also evidence for a distinct increase of sexual unaffectedness without disadvantageous uninhibition. A classification of the disturbances relative to the particular drugs did not reveal any differences within our cases. The sample "Gravistat" had significantly raised scores of neurotizism and here can also be observed an increase of inconvenient psychical disturbances. We recommend to give better information on the mode of action of the respective contraceptives. In cases of neurotic attitude a psychotherapeutical consultation between doctor and patient may diminish psychosexual disturbances as symptoms of the application of oral contraceptives.

Adult↗
PubMed1984

[Case report of tumors in the area of the foramen magnum].

This case study describes a spindle cell glioblastoma of the medulla oblongata (foramen magnum region) in a decreased patient aged 35 years. At the beginning of the illness which lasted about 7 months, the symptoms were quite uncharacteristic, and major neurological failure accompanied by tetraparesis and bulbar symptoms appeared only during the terminal phase, which was of several weeks duration. The specific clinical and diagnostic features of tumours at the magnum foramen, which account for only about 1% of all tumours of the CNS, and the difficulties they entail are described.

Adult↗