Biomedical subjects

E Hofmann

Publications and source records attributed to E Hofmann.

At least 73 records · Page 4Linked to original sources

PubMed1997

MR imaging-guided intravascular procedures: initial demonstration in a pig model.

With use of an open 1.5-T magnetic resonance (MR) imager and a tracking catheter, the authors successfully placed the catheter into the left or right sacral artery in pigs. The tracking catheter comprised a 5.3-F percutaneous transluminal angioplasty catheter with a small copper radio-frequency coil in its tip. With use of the coil as an antenna, the catheter tip position was projected in real time onto MR angiography road maps in two planes. Guidance of placement of the catheter with the MR angiography road maps allowed successful embolization, balloon occlusion, and transjugular intrahepatic puncture of the portal system. Specialized catheters can be tracked in vivo to allow MR guidance in intravascular interventional procedures.

Animals↗

PubMed1997

[Not Available].

Explore the source record for details and available documents.

Biotechnology↗

PubMed1997

[Cerebral cavernomas--clinical aspects and therapy].

Cavernomas are congenital cerebrovascular hamartomas which occur sporadic or familial. They are comprised of multiple sinusoidal spaces, filled with blood, without enlarged arterial feeders and draining veins. They occur in an estimated 0.4 to 0.5% of the population, with male and female patients equally affected and all ages represented. Lesions are singular or multiple (up to 20%) in the same patient and occur all over the central nervous system. Clinical representation is characterized by cross intracranial hemorrhage, seizures and focal neurological deficits. Unspecific symptoms, like headaches, vertigo and tinnitus were present in 25 to 30% of the patients. Asymptomatic cavernomas could be detected in up to 20% of the cases. The natural course revealed an annual risk of bleeding (0.6%) and a risk of developing epilepsy (1.5%). Microsurgical resection of a symptomatic lesion is the first choice of treatment. There is no mortality and the morbidity after resection of superficial cavernomas is below 5%. Deep seated cavernomas revealed a higher risk of postoperative neurological deficit. Therefore indication of operative removal in deep seated cavernomas should be carefully weighted up to the risk of natural course and generally neurological and radiological control is favoured. Radiosurgery is only indicated in progressively symptomatic cases which are surgical inaccessible.

Adolescent↗

PubMed1997

Clinical, morphological, biochemical, and neuroradiological features of mitochondrial encephalomyopathies. Presentation of 19 patients.

Nineteen patients (9 females, 10 males) with mitochondrial encephalomyopathies (ME) were studied. The diagnosis was established according to clinical and histopathological criteria. Leading clinical features were chronic progressive external ophthalmoplegia (CPEO) and muscle weakness in 95% of the patients. Pigmentary retinopathy was seen in 63%, and was always associated with CPEO. Hypacusis was present in 47% and cerebellar ataxia in 63% of patients. Clinical or electrophysiological signs of involvement of the central nervous system (CNS) were found in 21% of the patients. In muscle biopsy ragged red fibers were the predominant histopathological findings (100% of the patients), while COX-negative fibers were seen in 74%, deletions of the mitochondrial DNA in 42%, and defects of the respiratory chain in 32% of the patients. Increased blood lactate levels were found in 79% of the patients. Needle electromyography revealed myopathic features in 74%, features of denervation in 16%, and was normal in the remainder. Imaging studies showed cerebral atrophy in 58%, cerebellar atrophy in 16%, and hyperintense lesions of the white matter, pyramidal tract or extrapyramidal system in 16% of the cases. It is concluded that the clinical manifestations of ME can be very variable. Diagnosis of ME should be always considered in young patients presenting with CPEO and muscle weakness. In most cases, diagnosis can be made by a few selected investigations, while detection of genetic abnormalities may lead to the diagnosis in the remaining cases.

Adult↗

PubMed1996

Is computerized tomography ventricular abnormality related to cycloid psychosis?

Twenty-eight psychiatric patients with computerized tomography (CT) findings of ventricular abnormality most likely to result from prenatal/perinatal lesions (VA group) were compared to 28 sex- and age-matched psychiatric patients with normal neuroradiological findings (NCT group). The neuroradiological rater was blind to clinical psychiatric diagnoses and, vice versa, clinical diagnoses were established without knowledge of neuroradiological findings. A polydiagnostic approach (DSM-III-R, ICD-10, Leonhard Classification) was used for psychiatric diagnostic workup. Significantly more patients with cycloid psychoses (according to Leonhard's original description) were found in VA as compared to NCT patients. According to DSM-III-R and ICD-10, VA and NCT groups did not differ significantly regarding diagnostic distribution. Ventricular abnormalities that may reflect sequels of birth complications and/or adverse events during pregnancy may constitute one of the risk factors for developing cycloid psychosis as originally described by Leonhard.

Adult↗

PubMed1996

Structural basis of light harvesting by carotenoids: peridinin-chlorophyll-protein from Amphidinium carterae.

Peridinin-chlorophyll-protein, a water-soluble light-harvesting complex that has a blue-green absorbing carotenoid as its main pigment, is present in most photosynthetic dinoflagellates. Its high-resolution (2.0 angstrom) x-ray structure reveals a noncrystallographic trimer in which each polypeptide contains an unusual jellyroll fold of the alpha-helical amino- and carboxyl-terminal domains. These domains constitute a scaffold with pseudo-twofold symmetry surrounding a hydrophobic cavity filled by two lipid, eight peridinin, and two chlorophyll a molecules. The structural basis for efficient excitonic energy transfer from peridinin to chlorophyll is found in the clustering of peridinins around the chlorophylls at van der Waals distances.

Animals↗

PubMed1996

Characterization of transmembrane domains 6, 7, and 8 of MalF by mutational analysis.

Oligonucleotide mutagenesis was used to isolate mutations in membrane-spanning segments 6, 7, and 8 of MalF. MalF is a cytoplasmic membrane component of the binding protein-dependent maltose transport system in Escherichia coli. The current structural model predicts eight transmembrane domains for MalF. Membrane-spanning segments 6, 7, and 8 of MalF flank or are part of the EAA-X3-G-X9-I-X-LP consensus region present in the cytoplasmic membrane subunits of the bacterial ABC transporter superfamily members. Mutations with two novel phenotypes with respect to substrate specificity of the maltose transport system were isolated. One mutant grew on minimal maltose media but not on media containing either maltoheptaose or maltoheptaose plus maltose and was thus termed dextrin dominant negative. The other class of mutations led to a maltose minus but maltoheptaose plus phenotype. Nine of the isolated mutations leading to changes in substrate specificity were tightly clustered on one face of the postulated transmembrane helix 6. A similar clustering of mutations was detected in transmembrane domain 7. The majority of mutations in membrane-spanning segment 7 led to a protease-sensitive or a conditional phenotype with respect to MalF function or both. Mutations in transmembrane domain 8 appeared to be more randomly distributed. The majority of mutations in membrane-spanning segment 8 caused a Mal+ Dex- phenotype. Six Mal+ suppressor mutations isolated to two mutations in transmembrane domain 7 changed amino acid residues in membrane-spanning segment 6 or 8.

ATP-Binding Cassette Transporters↗

PubMed1996

[Acute organic psychosis after malaria tropica].

Neuropsychiatric complications in the course of plasmodium falciparum infection are usually summarized as cerebral malaria. Heterogeneous clinical symptoms, different courses and inconstant parasitemia, however, suggest different pathogenic mechanisms. We report a case of an acute symptomatic psychosis occurring two weeks after successful therapy of a primary manifestation of plasmodium falciparum infection. The diagnosis of meningoencephalitis was based on lymphocytic pleocytosis of cerebrospinal fluid and hyperintense lesions in cranial magnetic resonance imaging. Due to the lack of plasmodium falciparum parasitemia and of serological evidence of viral infection a final diagnosis was not possible. Considering the pertinent literature, an immune-mediated complication of plasmodium falciparum infection (acute disseminated encephalomyelitis, ADEM) appears to be more probable than a direct viral or plasmodium CNS infection. We propose to reverse the term cerebral malaria for the cases with direct pathogenic influence of plasmodium falciparum, and to distinguish it from cases with possible immune-mediated pathogenesis.

Adult↗

PubMed1996

Median corpectomy in cervical spondylotic multisegmental stenosis.

Cervical median corpectomy as an alternative to laminoplasty and laminectomy has been suggested as an effective treatment for cervical spondylotic myelopathy (CSM) in cases of multisegmental spondylotic stenosis. We report on our experience with this procedure with particular reference to neurological outcome and complications. Median corpectomy was performed in 17 cases (3 female, 14 male; mean age 59 yrs, (41-80 yrs.) with cervical myelopathy (CM) and radiologically diagnosed multisegmental spondylotic stenosis and spinal cord compression seen on MRI. The degree of stenosis was determined by means of the modified Pavlov's index (ratio between spinal canal width at the level of the intervertebral disc and the diameter of the vertebral body itself). 3/17 patients suffered from acute, 4/17 from subacute and 10/17 from chronic CM. Single level corpectomy was performed in 9 cases, one and a half vertebrae were removed in 2 cases and dual level corpectomy was performed in the remaining 6 cases. All patients received an autologous bone graft and AO - anterior plate stabilization or were stabilized as described by Morscher. Postoperative follow - up was possible in 16/17 cases over a mean time of 13.5 months. Myelopathy was graded according to Nurick's scale. Postoperatively, 12% with chronic CM improved by two grades, 38% (2 pts, with acute, 3 with subacute and 1 with chronic CM) improved by one grade. The other patients remained stable, none showed worsening of their myelopathy. Paresis improved in 92%, sensory deficits in 69%, spasticity in 73%, pain in 60%, and vegetative disturbances in 100% of all patients presenting these preoperative symptoms respectively. One patient died due to esophageal perforation and subsequent lethal mediastinitis caused by screw loosening 4 months following surgery and after initial neurological improvement. 4 other patients experienced screw loosening, three with acataposis, one remained clinically asymptomatic with concomitant graft displacement in two of these. One patient had to be re-operated due to a hematoma at the iliac crest and 2 suffered from a pelvic fracture of the spina iliaca at the site of graft removal. With respect to the neurological improvement, especially to the motor function and spasticity, median corpectomy can be regarded as an effective procedure in selected cases with cervical myelopathy, even when treatment related complications are taken into consideration.

Adult↗

PubMed1996

Interobserver agreement in assessing early CT signs of middle cerebral artery infarction.

PURPOSE: To assess the reliability of detecting signs of hemispheric infarction on CT scans obtained within 6 hours of the onset of symptoms. METHODS: A neuroradiologist selected 12 normal and 33 abnormal CT studies showing the hyperdense middle cerebral artery sign (HMCAS) (n = 10), brain swelling (n = 22), and parenchymal hypodensity (n = 33) from two series of 750 patients with recent onset of middle cerebral artery stroke. These selections served as the reference source for a nonblinded analysis of the initial and follow-up CT scans. Six neuroradiologists then reviewed the CT scans twice, first blinded then not blinded to clinical symptoms. They assessed the signs of infarction for each hemisphere separately and estimated the volume of abnormal parenchymal hypodensity in increments of 20% within the territory of the middle cerebral artery. RESULTS: Unblinding the reviewers did not change interobserver agreement significantly. The chance adjusted agreement was moderate to substantial: kappa = .62 (95% confidence interval [CI], .46 to .78) and kappa = .57 (95% CI, .33 to .81) for the HMCAS of the right and left hemisphere, respectively; kappa = .59 (95% CI, .47 to .71) and kappa = .56 (95% CI, .38 to .74) for focal brain swelling of the right and left hemisphere, respectively; and kappa = .58 (95% CI, .50 to .66) and kappa = .55 (95% CI, .32 to .67) for parenchymal hypodensity of the right and left hemisphere, respectively. Weighted kappa was .65 and .57 for the estimation of the hypodense tissue volume in the right and left hemisphere, respectively. Agreement with the reference source ranged from 73% to 93% for all variables and both hemispheres. CONCLUSION: Even with no clinical information, neuroradiologists can assess subtle CT signs of cerebral infarction within the first 6 hours of symptom onset with moderate to substantial interobserver agreement.

Brain Edema↗

PubMed1996

[Psychiatric sequelae of craniocerebral trauma--a review of the literature].

In a brief review psychiatric aspects of head-injured patients are discussed. The topic is put into a historical perspective. Examples of recent developments in head-trauma research are given. Differentiation between focal and diffuse brain injury is suggested to be of clinical relevance. Little is known as yet about the neuropsychologic and psychiatric sequelae of diffuse axonal injury to the brain.

Brain Concussion↗

PubMed1996

Cerebellar arachnoid cyst in a firesetter: the weight of organic lesions in arson.

A 52-year-old female patient was accused of arson; the patient had had an arachnoid cyst of the cerebellar vermis. Even after surgery, she showed marked instability of mood and pseudologia fantastica, but did not suffer from cognitive impairment. Possible associations of the presence of this cerebellar arachnoid cyst and behavioral disturbances are discussed.

Arachnoid Cysts↗

PubMed1996

[Radiofrequency catheter ablation of an accessory atrioventricular conduction pathway with persistent left superior vena cava and hypertrophic cardiomyopathy].

A 43-year-old man with a 30-year history of WPW-syndrome and a hypertrophic cardiomyopathy developed acute heart failure after onset of atrial fibrillation with fast antegrade conduction, which could be converted to sinus rhythm with antiarrhythmic medication. Catheterization of the coronary sinus during EP testing demonstrated a persistent left superior vena cava. The accessory pathway could be localized at the orifice of an atypical epicardial vein. It was successfully abolished after subvalvular placement of the electrode catheter in the left ventricle. This constellation indicates a combined defect during the regression of the sinus venosus to the sinus coronarius with persistence of conducting muscle fibers. Successful RF ablation procedure provides an obvious risk reduction as a result of a lower frequency of atrial fibrillation and the eliminated risk of ventricular fibrillation due to rapid conduction via an accessory pathway. Beyond that, harmless therapeutic treatment of hypertrophic cardiomyopathy with a calcium-channel-blocker (verapamil type) can follow RF ablation.

Adult↗

PubMed1995

Some methodological issues in neuroradiological research in psychiatry.

An outline is given of some of the methodological issues discussed in neuroradiological research on psychiatric illness. Strengths and shortcomings of magnetic resonance imaging (MRI) in depicting and quantifying brain structures are described. Temporal lobe anatomy and pathology are easily accessible to MRI, whereas limits on anatomical delineation hamper approaches to frontal lobe study. White matter hyperintense lesions are sensitively depicted by MRI, but specificity is limited. Distinction of vascular and primary degenerative dementia is considerably improved by CT and MRI analysis. Computed tomography (CT) and MRI have enhanced the understanding of treatable organic psychiatric disorders, e.g., normal pressure hydrocephalus. Subcortical and white matter pathology has been replicated in CT and MRI studies of late-onset psychiatric disorders, clinical overlap with cerebrovascular disease or neurodegeneration may be of import. Transcranial sonography findings of brainstem structural change specific to unipolar depression may contribute to the understanding of affective psychoses. Magnetic resonance spectroscopy and functional MRI are likely to stimulate psychiatric research in the future.

Brain↗

PubMed1995

Disturbances of cerebrospinal fluid (CSF) circulation--neuropsychiatric symptoms and neuroradiological contribution.

The present study aimed at relating dementia, pseudo-neurasthenic and affective organic brain syndromes to underlying type of CSF flow disorder and to subsequent alteration of anatomy. T2*-weighted magnetic resonance imaging (MRI) in the midsagittal plane permitted an analysis of aqueductal CSF flow phenomena and hydrocephalus-induced elevation, thinning and dorsal impingement of the corpus callosum. Furthermore, the width of the third ventricle was measured on the transverse scout images. 72 patients with communicating hydrocephalus (increased aqueductal CSF pulsations) and 26 patients with aqueductal stenosis (absence of aqueductal flow phenomena) were compared with 22 controls. Dementia and affective disorders were distributed equally among both CSF flow subgroups whereas pseudo-neurasthenic syndromes were observed more frequently in non-communicating hydrocephalus (p < 0.03). Alzheimer-type and multiinfarct dementia syndromes were found more frequently in communicating hydrocephalus whereas non-classifiable dementia showed some predilection for non-communicating hydrocephalus. Callosal height, area and third ventricular width did not predict affective or pseudoneurasthenic disorder whereas third ventricular width (p < 0.01) and callosal area (p < 0.05) discriminated between demented and non-demented patients. Dorsal impingement of the corpus callosum by the falx was a non-specific finding.

Cerebral Aqueduct↗

PubMed1995

The corpus callosum in communicating and noncommunicating hydrocephalus.

To investigate morphological changes in the corpus callosum in hydrocephalus and to correlate them with clinical findings we studied sagittal T2*-weighted cine MR images of 163 patients with hydrocephalus. The height, length and cross-sectional area of the corpus callosum were measured and related to the type of cerebrospinal fluid flow anomaly and to clinical features, especially dementia. With expansion of the lateral ventricles the corpus callosum showed mainly elevation of its body and, to a lesser degree, increase in length. Upward bowing was more pronounced in noncommunicating than in communicating hydrocephalus. Dorsal impingement on the corpus callosum by the free edge of the falx correlated with the height of the corpus callosum. Cross-sectional area did not correlate with either height, length or impingement; it was, however, the strongest anatomical discriminator between demented and nondemented patients. The area of the corpus callosum was significantly smaller in patients with white matter disease. Our findings suggest that, due to its plasticity, the corpus callosum can to some degree resist distortion in hydrocephalus. Dementia, although statistically related to atrophy of the corpus callosum, is possibly more directly related to white matter disease.

Case-Control Studies↗

PubMed1995

Isolated meningeal tuberculoma mimicking meningioma: case report.

A 47-year-old German female patient is described with intracranial tuberculoma of the dura mater without history or evidence of tuberculosis and a negative tuberculin reaction. Computed tomography and magnetic resonance imaging and angiography resembled a meningioma. Diagnosis was verified by histology and identification of mycobacterium tuberculosis. After removal of the granuloma and high-dose chemotherapy, the patient was free of disease. Tuberculoma of the dura mater is an extremely rare disease in the Western European population.

Diagnosis, Differential↗

PubMed1995

Preoperative and postoperative follow-up in high-grade gliomas: comparison of transcranial color-coded real-time sonography and computed tomography findings.

Twenty patients with high-grade gliomas were prospectively studied by pre- and postoperative transcranial color-coded real-time sonography (TCCS) and CT, to determine the sensitivity of TCCS in the identification of residual tumor and tumor regrowth. Each patient was subjected to preoperative and early postoperative CT (postoperative day 1) and TCCS examinations (postoperative days 6 to 8) and subsequent CT and TCCS follow-up examinations within a time interval of 6 weeks to 3 months. In eight patients, a total of 15 biopsy specimens were intraoperatively obtained from the wall of the resection cavity. Histological findings of intraoperative biopsy specimens showed that hyperechogenic areas adjacent to the resection cavity always contained residual tumor tissue. Early postoperative TCCS identified these hyperechogenic areas in 19 of 20 patients. In 12 patients, postoperative CT revealed contrast enhancement at the resection margin, indicating residual tumor. In these patients the extension of these hyperechogenic areas on TCCS exceeded the contrast-enhancing areas on CT by a mean of 58%. In eight patients, postoperative CT displayed no contrast enhancement along the border of resection. TCCS and histological findings indicated residual tumor in seven of these eight patients. The size of the hyperechogenic lesions identified by postoperative TCCS increased in time and follow-up examinations revealed that tumor regrowth arose from these hyperechogenic areas in all patients. In four patients, tumor regrowth was identified, on average 0.7 months earlier by TCCS than by CT. From these data we conclude that the sensitivity of TCCS in detection of residual tumor and tumor regrowth seems to be superior to CT. The value of TCCS requires further clarification by comparative studies including histology and MRI.

Biopsy↗