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Biomedical subjects

H Stefan

Publications and source records attributed to H Stefan.

At least 109 records · Page 6Linked to original sources
PubMed1996

Temporal lobe epilepsy: evidence for interictal uncoupling of blood flow and glucose metabolism in temporomesial structures.

Measurements of regional cerebral glucose metabolism (rCMRGlc) and blood flow (rCBF) are widely considered exchangeable for the detection of dysfunctional zones in temporal lobe epilepsy (TLE). However, the underlying assumption of preserved coupling of rCBF and rcMRGlc is questionable and requires verification. Thirteen patients with unilateral mesiolimbic TLE underwent interictal positron emission tomography (PET) measurements of rCBF using [15(O)]butanol and of rcMRGlc using (18)FDG. rcMRGlc, rCBF and glucose extraction fraction (rGEF) were obtained from temporomesial and temporolateral structures. When compared to the respective homotopic contralateral reference region, in temporomesial structures ipsilateral to the EEG-defined focus ('dysfunctional zone'), average rCMRGlc and rGEF were decreased while rCBF was unaffected. Analysis of (18)FDG kinetics revealed that (18)FDG transport was unaltered but the hexokinase reaction was specifically decreased. In the temporolateral structures, no such mismatch between metabolism and blood flow was observed. In mesiolimbic TLE, interictal rCMRGlc-PET is superior to rCBF-PET with respect to the sensitivity to detect regional functional abnormalities. This seems to be due to focal uncoupling of glucose metabolism and blood-brain barrier transport or blood flow. We hypothesize that the observed uncoupling of transport and metabolism may be characteristic of epileptogenic zones in TLE of typical etiology.

Adult↗
PubMed1996

[Dissection of the carotid artery and vertebral artery--diagnosis and therapy].

Carotid and vertebral artery dissections typically occur in young adults after major trauma, although they can arise spontaneously or after trivial injury. Many patients with carotid dissections have minor symptoms such as a subject bruit or Horner's syndrome. Cephalic pain is also frequent and often inaugural in carotid dissection. However, extracranial dissection is a well recognised cause of ischaemic stroke. The diagnosis of dissection was based on angiographic findings. Noninvasive imaging also allows prompt and reliable diagnosis. Our goal was to demonstrate the spectrum of neuroradiologic (CT, MR and angiographic) findings in craniocervical arterial dissection and compare the diagnostic utility of CT, MR, MR angiography. Clinical data imaging studies, and outcome were reviewed and compared with the results in four patients with carotid artery dissection.

Adolescent↗
PubMed1996

["Tailoring" resections in drug refractory temporal lobe epilepsy].

On the basis of results obtained from extensive pre- and intraoperative diagnostic investigations of 69 patients, minimalisation of epileptogenic brain tissue resection was strived for. The extent of resection ranged from selective amygdalohippocampectomy up to "en bloc" standard resections, and in rare cases even beyond these. In the majority of cases however, tailoring allowed smaller resections than the standard "en bloc" resections. The outcome of tailoring in regard to seizure control as well as verbal memory and visual performance show that this method should be favoured in epilepsy surgery of temporal lobe epilepsies.

Adolescent↗
PubMed1996

[Follow-up studies and disorders of endocrinologic function in MELAS syndrome].

The clinical course of MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, stroke-like episodes) is described in five cases. The age of onset was 9.2 years on average. Cerebral symptoms occurred at an age of 24.6 years on average. The diagnosis was only made later. Three patients died during the follow-up period. The mean age at death was 33.3 years, the average duration of the disease, 19.6 years. All patients suffered from progressive hearing loss, multiple strokes, and complex-partial and generalized seizures. They all had short stature, normal early development and 'ragged red fibers' in the muscle biopsy. Imaging studies (CT and MRI) showed bilateral calcification of basal ganglia and multiple strokes. One patient, admitted with epileptic status as initial symptom, showed lymphocytic pleocytosis in the cerebrospinal fluid; thus, in her case the differential diagnosis included encephalitis. Four patients were studied by dynamic endocrinological testing. Endocrinological disturbances were detected in three patients. Two of them suffered from hypothalamic-pituitary failure and one patient exhibited hyperprolactinemia. Endocrinological disturbances were considered an expression of the underlying cytopathy. Cerebral symptoms occurred rather late in the course of the disease and indicated poor prognosis.

Adolescent↗
PubMed1995

[Acute meningoencephalitis--diagnosis and therapy].

Meningoencephalitis is still associated with a mortality rate of up to 30% and early selective treatment is extremely important. Whenever the disease is suspected, lumbar puncture should be performed immediately with the aim of differentiating on the basis of the cell count and cell picture between the various forms of inflammation namely bacterial, viral, and other special forms (tuberculous, leptospiral, spirochaete-associated or fungus-associated infections). Bacterial meningoencephalitis requires immediate antibiotic treatment. The present article discusses the choice of suitable medication. When herpes encephalitis is suspected, acyclovir should be administered immediately. The diagnosis and treatment of tuberculous meningoencephalitis are also briefly discussed. Infections with less common pathogens are not considered in the present article.

Acute Disease↗
PubMed1995

Effects of vagus nerve stimulation on amino acids and other metabolites in the CSF of patients with partial seizures.

Electrical stimulation of the vagus nerve (VNS) is a new method for the treatment of patients with medically intractable epilepsy. Sixteen patients, ten of whom participated in a larger multicenter double-blind trial on the efficacy of VNS in epilepsy, and six who participated in pilot studies, consented to participate in the present study. Ten patients received HIGH stimulation and six patients LOW stimulation for the 3-month trial. Cerebrospinal fluid (CSF) samples (16 ml) were collected both before and after 3 months of VNS. Amino acid and neurotransmitter metabolites were analyzed. Four patients responded to VS with more than a 25% seizure reduction after 3 months. Mean and median concentrations of phosphoethanolamine (PEA) increased in responders and decreased in nonresponders. Free GABA increased in both groups but more so in the nonresponders. After 9 months of VS (6-9 months on HIGH stimulation) 4 of 15 patients had more than 40% seizure reduction. There were significant correlations between seizure reduction and increases in asparagine, phenylalanine, PEA, alanine and tryptophan concentrations. Comparison between patients with HIGH or LOW stimulation showed a significant increase in ethanolamine (EA) in the HIGH group and a decrease in glutamine in the LOW group. All patients regardless of response or stimulation intensity showed significantly increased total and free GABA levels. A decrease in CSF aspartate was marginally significant. Other trends were decreases in glutamate and increases in 5-hydroxyindoleacetic acid. Chronic VNS appears to have an effect on various amino acids pools in the brain.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Purulent meningoencephalitis--studies of disease progression and prognosis].

The course of acute purulent meningitis and meningocephalitis was investigated in 101 patients using records and a questionnaire directed to all patients. Patients who survived meningoencephalitis were asked to come to a neurological examination. Neuropsychological status, EEG and Tc-HMPAO-Spect were also performed in these patients. The patients were treated with a combination of three antimicrobial agents which was commonly used at our hospital during the investigation time consisting of penicillin, a cephalosporine of the third generation and an aminoglycoside. 40% of the patients suffered from more or less severe neurologic sequelae; remaining cognitive deficits were also frequent. On the whole there was a tendency towards improvement in patients who suffered from less severe deficits at the time of discharge from hospital, patients with more severe deficits also showed slight improvement but generally did not reach a restitutio ad integrum. Regarding this, in our opinion a broad initial antimicrobial therapy should be used, although a statistically significant improvement of the patient's outcome by this could not be shown. Lethality as well as the frequency of complications do not seem to differ over many years although antimicrobial and intensive care treatment were improved. Thus, the outcome seems to depend largely on the occurrence of secondary focal complications or brain oedema.

Adult↗
PubMed1995

Chemosensory event-related potentials in patients with temporal lobe epilepsy.

We investigated chemosensory functions in patients with temporal lobe epilepsy (TLE) to discover whether olfactory and trigeminal stimuli applied either ipsilaterally or contralaterally to the epileptic focus are processed differently. Twenty-two patients were investigated, 12 of whom had epilepsy with a focus located in left temporal lobe (LTL). The remaining 10 patients had a right temporal lobe (RTL) focus. Input from the trigeminal system was examined by use of CO2; input from the olfactory system was evaluated with vanillin and hydrogen sulfide as stimuli. Chemosensory function was assessed by evaluation of chemosensory event-related potentials (CSERP) and the patients' verbal reports in an odor identification test. In both groups of patients, prolonged CSERP latencies were noted after stimulation of the left nostril with CO2 as compared with stimulation of the right nostril. In contrast, a different pattern emerged for olfactory stimuli. After right-sided olfactory stimulation, latencies were prolonged in patients with right-sided epileptical foci. Similarly, when the left nostril was stimulated in patients with a left-sided focus, CSERP latencies were prolonged. Thus, neocortical processing of olfactory, but not trigeminally mediated information evidently is affected by functional lesions of the temporal lobe. After olfactory stimulation in patients with a right-sided focus, the distribution of amplitudes was different from normal. Moreover, analyses showed nonoverlapping 95% confidence intervals (CI) for latency N1 when vanillin was applied to the right nostril. These results indicate that RTL may play a different role in processing of olfactory information as compared with LTL.

Adult↗
PubMed1995

[Diagnostic methods in the assessment of anosmia in neurologic diseases].

Several important neurological diseases can impair the sense of smell. In the past the substances generally used for testing were not well defined, and the testing procedures did not follow the rules of psychophysical test procedures. Therefore, in this paper standardized new methods of testing the olfactory system are presented. Based on published data, the University of Pennsylvania Smell Identification Test is the most suitable test for screening purposes. More detailed information can be obtained when using the Connecticut Chemosensory Clinical Research Center's Odor Identification Test that includes the possibility of determining the olfactory threshold. Additionally, a new method that combines the testing of olfactory threshold, odor discrimination and odor identification with the recording of specific olfactory-evoked potentials is described. The latter test is especially useful when objective neurophysiological data are requested.

Cerebral Cortex↗
PubMed1995

[Disorders of intestinal rotation and fixation in older children].

The authors discuss five older children where malrotation of the gut was diagnosed. The youngest child was three years old, the oldest 16 years. In three children the malrotation was diagnosed from clinical symptoms and examination by imaging methods, in two it was detected by chance during operation. In the two children where the impaired rotation of the gut was detected on operation, non-rotation was involved. In the remaining three children twice a left side paraduodenal hernia was diagnosed and once an external stenosis of the duodenum by Ladd's bands.

Adolescent↗
PubMed1994

[Mechanical lesions of the peripheral nervous system. Possible damage at work and leisure].

For the most part, mechanical injuries to peripheral nerves occurring at work or at play as a result of closed traumatization, are caused by compressive, stretching/shearing or vibrational forces. In a patient in whom various compression lesions of peripheral nerves recur, the possible presence of a predisposing hereditary neuropathy must be considered. Modern magnetic resonance imaging is capable of clarifying the causes and conditions of compression injuries, in particular in the region of the tunnel: presence of osteophytes, other space-consuming processes or anatomical narrowing of the tunnel. Injury sequelae, for example in the case of carpal tunnel syndrome affecting the median nerve, or tendinopathies, can also be visualized. A number of lesions and their triggering mechanisms that occur during work or leisure are described.

Accidents, Occupational↗
PubMed1994

Reconstruction of the penis after necrosis due to circumcision burn.

Penile necrosis secondary to circumcision by an electrical scalpel in a 2 years and-2-months-old boy occurred. After healing of the electric burn only stumps of the erectile bodies and strictured urethral meatus remained. Penile shaft reconstruction by corpora mobilisation and detachment of the crura from the pubo-ischial rami was performed. This procedure gained 6 cm of a new length of the penis. To prevent readhesions to the pubo-ischial rami the penis was buried in a scrotal tunnel. Six months later the denuded shaft was resurfaced with one split-thickness skin graft and a zigzag seam on the ventral side was made. The patient voids with good stream, has spontaneous erections and nocturnal emissions. During 10 years of follow-up after the reconstruction two complications, namely a stricture of the urethra and a slight dorsal tethering of the penis caused by a scarred pubic skin were treated. The problems of reconstruction and resurfacing of the penis in childhood are discussed.

Child, Preschool↗
PubMed1994

Magnetic source localization and morphological changes in temporal lobe epilepsy: comparison of MEG/EEG, ECoG and volumetric MRI in presurgical evaluation of operated patients.

Is MEG source analysis able to precisely locate the primary focal epileptic activity? 22 patients with pharmacoresistant temporal lobe epilepsy were recorded during presurgical evaluation simultaneously with multichannel MEG/EEG and invasive (subdural) electrodes to evaluate the increase of information gained by MEG concerning the localization of focal epileptic activity and lesions. With this systematic study it should become clearer how often MEG can establish a diagnostic bridge between function and morphology. In addition, MEG localization accuracy of focal epileptic activity was to be validated empirically by invasive EEG recordings and postsurgical outcome. Spikes in the MEG were used for magnetic source localization, and the result was combined with magnetic resonance imaging (MRI). All patients definitely suffered from temporal lobe epilepsy and revealed a structural abnormality in MRI. 17 patients with lesions in the temporal lobe were operated meanwhile and became markedly improved or seizure free. In 7 of 8 patients with a tumor and validated operation outcome, a very close correlation of the 3D-magnetic source localization and the border of the tumor in the brain was found (distance less than 10 mm). In 8 of 9 patients with a temporal/hippocampal atrophy and validated operation outcome, dipoles of epileptiform activity were located within the atrophic lobe.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed1994

[Continent enterocystoplasty in urinary bladder exstrophy].

During the last two years from 1992 to February 1994 5 patients (2 girls and 3 boys with median age 7 years) underwent construction of continent large-capacity low pressure reservoir for failed bladder exstrophy reconstruction. Small bladder with inadequate capacity, decreased detrusor compliance and urinary incontinence were the indication for enterocystoplasty. The pouches were reconstructed from detubularized, reconfigured bowel using incorporated bladder remnant. Bowel segments included ileocecum in 4 patients and ascendig colon in one. Reconstruction of the vesical neck was accomplished by the Young-Dees-Leadbetter procedure in 4 patients. Two children underwent reimplantation of ureters into the bladder and three ureters of two patients were reimplanted by the Goodwin technique into the colon. The Mitrofanoff continence mechanism using appendix was applied in 3 patients. Preoperation bladder capacities were 12 up to 100 mL and after enterocystoplasties improved to mean 300 mL and maximum 550 mL. Four patients are in complete urinary retention and are managed by clean intermittent catheterisation every 3 to 4 hours. One patient voids spontaneously with little residual urine by abdominal straining and pelvic muscle relaxation alone. Short-term follow-up (3 months to 2 years) showed stable renal function in all patients. In 2 patients with preoperative hydronephrosis caliectasis decreased. This series supports the efficacy of continent enterocystoplasty as an alternative procedure to previous forms of urinary diversion in the management of failed exstrophy reconstruction.

Bladder Exstrophy↗