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Biomedical subjects

J Schramm

Publications and source records attributed to J Schramm.

At least 163 records · Page 9Linked to original sources
PubMed1996

Clinical, radiological, and therapeutic features of pleomorphic xanthoastrocytoma: report of three patients and review of the literature.

Two out of three patients with pleomorphic xanthoastrocytoma were initially misdiagnosed and correctly interpreted only at tumour recurrence, with progression to malignancy in one. The third patient presented with a remarkably long history of epilepsy. Pleomorphic xanthoastrocytoma is a low grade astrocytoma that is still confused with other tumours. Because pleomorphic xanthoastrocytoma can become malignant even after many years of benign behaviour, a long term follow up is necessary.

Adolescent↗
PubMed1996

Intrinsic tumors of the insula: a prospective surgical study of 30 patients.

Intrinsic insular tumors are frequently excluded from surgical treatment. The authors propose a more extensive approach to these lesions based on the results of this prospective series. From September 1993 to January 1995, 30 patients (18 males and 12 females; mean age 42 years) harboring benign (15 patients) or malignant (15 patients) tumors involving the insula underwent surgical treatment. The dominant and nondominant hemispheres were both affected in 15 cases. Two groups were defined on the basis of preoperative magnetic resonance (MR) imaging: 14 lesions were restricted to the insula and the corresponding opercula; the other 16 lesions also involved other mesocortical and/or allocortical areas. Most patients displayed only mild preoperative symptoms. The median score according to the Karnofsky performance scale was 90. Microsurgical removal was achieved via a transsylvian approach in nine cases and via a frontal and/or temporal approach in 21 cases. According to early postoperative MR imaging, complete tumor removal (100%) was seen in five patients, nearly complete (> 80%) in 21, and incomplete resection (50%-80%) in four patients. There was no operative mortality; 19 patients (63%) experienced immediate postoperative morbidity, including reduced performance. After a mean follow-up review of 8.5 months two of 21 patients suffered permanent deficits, accounting for an overall operative morbidity of 10%. At the mean time of review, three patients with Grade IV tumors had died of tumor recurrence. The authors conclude that low-grade intrinsic insular tumors, as well as Grade III tumors, can be removed with favorable results in the majority of patients. Surgery to excise glioblastomas should only be considered for patients with good preoperative performance and young age.

Adult↗
PubMed1996

Functional results after resective procedures involving the supplementary motor area.

In this article, the authors report their experience with surgically induced supplementary motor area (SMA) deficiency syndrome in a prospective clinical trial of 28 patients who underwent surgery for tumorous (19 patients) or nontumorous (nine patients) lesions. The dominant side was affected in 17 patients and the nondominant side in 11 patients. The primary presenting symptoms included seizure activity (23 patients), hemiparesis (four patients), and aphasia (one patient). Functional topographic mapping, achieved by phase reversal of somatosensory evoked potentials, allowed precise localization of the central sulcus in 25 of the 28 patients. Motor evoked potential (MEP) monitoring, which was performed successfully in 13 of 15 cases during the resective procedure, showed no significant changes in the potentials in any patient. Immediately after surgery, 25 (89%) of the 28 patients displayed additional neurological deficits (aphasia and/or hemiparesis) that depended on the extent of the SMA resection. In 12 patients the SMA was resected completely: nine of these patients demonstrated a complete and three an incomplete deficit. In 16 patients the SMA resection was incomplete: 13 of these patients displayed an incomplete deficit, whereas three had no deficit. Neurological disorders resolved completely within 3 to 42 days (mean 11 days), except for a minimal disturbance of fine motor and/or speech function in complex tasks or at high speed. Electromagnetically elicited MEPs, examined postoperatively in five patients, were initially absent but recovered with improvement of motor function. In conclusion, although the SMA is known to control important functions such as initiation of motor activity or speech, our findings show that unilateral SMA removal can be accomplished without resulting in significant permanent deficits. Functional topographic mapping and monitoring facilitate the exact delineation of the adequate resection plane along the precentral sulcus, and postoperative magnetic resonance imaging allows precise correlation of clinical and anatomical data.

Adolescent↗
PubMed1996

Dysembryoplastic neuroepithelial tumors: MR and CT evaluation.

PURPOSE: To evaluate dysembryoplastic neuroepithelial tumors (DNTs) on MR and CT studies and to compare DNT with other frequently encountered epileptogenic glioneuronal lesions. METHODS: We analyzed the MR images and CT scans of 16 patients who had complex partial epilepsy and DNT with respect to tumor location, size, CT density, MR signal intensity, mass effect, contrast enhancement, and heterogeneity, and compared these features with CT and MR findings in 51 cases of ganglioglioma and 33 cases of glioneuronal malformation. RESULTS: DNTs were located in the temporal lobe in 14 patients and in the frontal lobe in 2 patients. The cortex was involved in all cases and the subcortical white matter in 10 cases. Fifty percent of the tumors had poorly defined contours. On MR images, 14 DNTs had multiple cysts and 2 had single cysts. Contrast enhancement was observed in 6 DNTs, and mass effect was present in 9. CT scans disclosed moderately hypodense lesions in 7 patients and markedly hypodense cystic lesions in 6 patients. Two DNTs were calcified. Tumor hemorrhage with perifocal edema was observed in 1 case. Contrary to previous reports, slow but definite tumor growth was present during a 13-year period in 2 of 6 patients in whom serial CT or MR studies were obtained. CONCLUSION: A multicystic appearance on MR images is a characteristic feature of DNT and corresponds to its myxoid matrix and multinodular architecture. This feature is rare in gangliogliomas and glioneuronal malformations, and, as such, may help differentiate DNTs from these disorders.

Adolescent↗
PubMed1996

[Vertebral body replacement with a rib segment block in transthoracic intervention].

The aim of this clinical report is to describe the outcome of 7 patients regarding the efficiency of a vertebral body replacement with rib bone for destructive lesions in the thoracic spine. In these patients, an autologous bone block shaped from four rib segments, was used as a vertebral body replacement. In order to compose the bone block, the ribs were fused by means of one or two commercialized titanium screws. In a retrospective study the following parameters were analysed: neurological status, rate of bony fusion, primary correction gain, secondary correction loss. Mean time of follow-up was eleven months (range 6-20). Neurological improvement was found in 83.3% of patients treated with ventral decompression. Immediate postoperative gain of correction was 9.4 angle degrees, secondary loss of correction was 11.4 angle degrees, the latter resulting from the impression of the rib segments into the adjacent vertebrae. Radiological bony fusion of the rib implants could be observed in all cases. To avoid a secondary loss of correction, ventral fusion using an osteosynthesis plate and, in singular cases, the dorsal implantation of a fixateur interne is advantageous. An additional advantage of this new method is that autologous bone harvesting is accomplished during the surgical approach, rendering a separate approach for this purpose superfluous (thus shortening operation time, reducing morbidity and operative complications). We conclude from our results that the composed rib block is an attractive alternative vertebral body replacement which provides sufficient stability and osteogenic capacity.

Adult↗
PubMed1995

Titanium intervertebral disc and instrumentation for fusion in anterior cervical discectomy. Technical note.

A new titanium intervertebral disc for fusion in anterior cervical discectomy is described. The advantages of the device, apart from avoidance of graft explanation, include biocompatibility, simple instrumentation, availability of different forms and sizes, and restoration of physiologic lordosis. Following extensive biochemical testing and implantation in animals, first long-term experience in 15 patients with an average follow-up of three years (28-73 month) are described. Infections, anterior angulation deformities, and graft extrusions were not observed in this series.

Adult↗
PubMed1995

The clinical and prognostic relevance of the postictal slow focus in the electrocorticogram.

Electrocorticograms of 192 complex partial seizures which were recorded via chronically implanted subdural electrodes during presurgical evaluation of 64 patients with medically intractable epilepsy were visually analysed. The objective was to assess the diagnostic and prognostic relevance of postictal slow foci (PISF) in the electrocorticogram which were defined as focal isoelectric activity or as a focal burst-suppression pattern. The following results were obtained: (1) PISF were seen in a total of 114 of 192 seizures (59.4%), (2) 48 of 64 patients (75%) demonstrated at least 1 PISF in 3 seizures, (3) PISF were more frequent in seizures of temporal lobe origin (66%) than in those of extratemporal origin (33.3%), (4) no PISF developed if the electrographic seizure duration was < 32 sec, (5) PISF were (predominantly) localized in the lobe of seizure origin in 85% of the seizures, (6) there was a strong correlation between frequent occurrence of temporal PISF and favourable seizure outcome following temporal lobe surgery. In conclusion, PISF contribute valuable data as to the localization of the epileptogenic zone during presurgical evaluation of epilepsy and indicate favourable seizure outcome following temporal lobe surgery.

Adolescent↗
PubMed1995

Multiple polymorphisms, but no mutations, in the WAF1/CIP1 gene in human brain tumours.

The cyclin kinase inhibitor WAF1/CIP1, also termed CDKN1, mediates p53-induced cell cycle arrest in response to DNA damage. This property makes it an attractive tumour-suppressor candidate for a p53-associated tumour-suppressor gene. In order to investigate the role of WAF1/CIP1 in the pathogenesis of primary human brain tumours we performed single-stranded conformation polymorphism (SSCP) analysis and direct sequencing of exon 2 of the gene in a representative series of 158 brain tumours and corresponding blood samples. In addition, all tumours were examined for mutations in exons 5-8 of the p53 gene. Analysis of WAF1/CIP1 revealed multiple polymorphisms, the most abundant being AGC-->AGA (Ser-->Arg) at codon 31 with an allele frequency of 8.5%. Less common polymorphisms included GTG-->GGG (Val-->Gly) at codon 25, GCC-->ACC (Ala-->Thr) at codon 64, CGC-->CTC (Arg-->Leu) at codon 32, GGC-->AGC (Gly-->Ser) at codon 14 and GCG-->GTG (Ala-->Val) at codon 39 each with an allele frequency of 0.3%. These polymorphisms were all located in a conserved region of exon 2. Two of the polymorphisms were also seen in a group of 157 healthy controls indicating that WAF1/CIP1 polymorphisms do not predispose to cancer. None of the tumours included in our series showed a somatic mutation in WAF1/CIP1. All samples were also analysed for loss of heterozygosity on the short arm of chromosome 6 in the region of the WAF1/CIP1 locus. Allelic loss was observed in only one patient with a glioblastoma. Mutations in the p53 gene were found in 22 of 158 tumours. No association was found between any polymorphism of the WAF1/CIP1 gene, p53 mutations and histopathological tumour type. Our data indicate that WAF1/CIP1 mutations are probably not involved in the formation of primary human brain tumours.

Base Sequence↗
PubMed1995

Shared allelic losses on chromosomes 1p and 19q suggest a common origin of oligodendroglioma and oligoastrocytoma.

Loss of heterozygosity (LOH) in specific chromosomal regions, which are likely to harbor tumor suppressor genes, has been associated with human gliomas. In this study we have analyzed astrocytic and oligodendroglial tumors for LOH on chromosomes 1 and 19. By microsatellite analysis LOH was found on chromosome arm 1p in 6/15 oligodendrogliomas WHO grade II and III, 12/25 oligoastrocytomas WHO grade II and III, 6/79 glioblastomas WHO grade IV, 5/44 astrocytomas WHO grade II and III and 0/23 pilocytic astrocytomas WHO grade I. The high incidence of LOH on chromosome arm 1p in oligodendrogliomas and oligoastrocytomas indicates that a putative tumor suppressor gene in this region is involved in the formation of gliomas with oligodendroglial features. Furthermore, the frequent involvement of chromosome arm 1p in oligodendrogliomas and oligoastrocytomas, but not in astrocytomas, suggests that genetically oligoastrocytoma is more similar to oligodendroglioma than to astrocytoma. In order to support this hypothesis, oligodendroglial and astrocytic areas in three mixed oligoastrocytomas were examined differentially for LOH 1p and for LOH 19q, the second genetic region believed to be affected in these tumors. All three tumors had LOH of 1p and LOH of 19q in both areas of oligodendroglial and of astrocytic differentiation. These findings show that the astrocytic and oligodendroglial portions of oligoastrocytoma share molecular genetic features and probably are of monoclonal origin.

Alleles↗
PubMed1995

Evidence for subarachnoid spread in the development of multiple meningiomas.

Meningiomas are among the most common human brain tumors. Occasionally patients develop multiple meningiomas. While it has been surmised that these are multiple primary meningiomas, it is possible that they represent spread of a single primary tumor. Recently, the neurofibromatosis type 2 (NF2) tumor suppressor gene has been shown to carry mutations in meningiomas. In the present study we have analyzed multiple meningiomas from two patients for point mutations in the NF2 gene by SSCP analysis and direct sequencing. We detected point mutations in the meningiomas from both patients. The first patient from which six tumors were available had a three base pair deletion in the splice donor region of exon 7. All tumors showed the identical mutation. The second patient with two independent meningiomas had a nonsense mutation in exon 8 which was the same in both tumors. Analysis of constitutional DNA revealed a wildtype DNA sequence in both cases. There was no family history of neurofibromatosis type 2 in either patient. These data provide strong evidence for a monoclonal origin of multiple meningiomas. Early subarachnoid spread is the most likely mechanism for the formation of these tumors.

Aged↗
PubMed1995

Surgical treatment of temporal lobe epilepsy: clinical, radiological, and histopathological findings in 178 patients.

The surgical treatment of pharmacoresistant temporal lobe epilepsy is increasing rapidly. The correlation of preoperative MRI, histopathological findings, and postoperative seizure control is reported for 178 patients with chronic medically intractable temporal lobe epilepsy who were operated on between November 1987 and January 1993. Histopathologically there were distinct structural abnormalities in 97.2% of the surgical specimens. Signal abnormalities on MRI were present in 98.7% of patients with neoplastic lesions (n = 79), 76.6% of patients with non-neoplastic focal lesions (n = 55), and 69.2% of patients with Ammon's horn sclerosis (n = 39). Overall, structural abnormalities were detected by MRI in 82.7% of all patients. The mean postoperative follow up period was three years. Some 92% of the patients benefited from surgery: 103 patients (61.7%) were seizure free, 26 (15.5%) had no more than two seizures a year, and 24 (14.4%) showed a reduction of seizure frequency of at least 75%. Fourteen patients (8.4%) had a < 75% reduction of seizure frequency. The percentage of patients who were completely free of seizures after operation was 68.5% for patients with neoplastic lesions, 66.7% for Ammon's horn sclerosis, and 54.0% for patients with non-neoplastic focal lesions. By contrast, none of the patients in whom histopathological findings were normal became seizure free postoperatively. The data show that the presence of focal lesions or Ammon's horn sclerosis as determined by histopathological examination is associated with improved postoperative seizure control compared with patients without specific pathological findings. Brain MRI was very sensitive in detecting neoplasms; however, its sensitivity and specificity were limited with respect to non-neoplastic focal lesions and Ammon's horn sclerosis. Improvement of imaging techniques may provide a more precise definition of structural lesions in these cases and facilitate limited surgical resections of the epileptogenic area rather than standardised anatomical resections.

Adolescent↗
PubMed1995

Hemispherical deafferentation: an alternative to functional hemispherectomy.

An alternative technique for so-called functional hemispherectomy has been developed to be used for the classical indications of hemispherectomy or the various modifications of functional hemispherectomy. The technique entails a smaller trepanation, less operation time, and less blood loss, and it leaves more brain tissue in place as compared with other functional hemispherectomy techniques. It starts with either hippocampectomy alone or with hippocampectomy and anterior temporal lobectomy. After this, deafferentation of the white matter of the temporal, occipital, parietal, and frontal lobe, using either a transcortical transventricular approach along the outline of the lateral ventricle or a sylvian key hole approach, is performed. The technique includes a transventricular callosotomy, and it leaves in place only a small portion of the suprainsular cortex and the insular cortex. However, as one modification, removal of the insular cortex can easily be performed, if necessary, and, as a second modification, the entire transventricular deafferentation can be performed through a sylvian key hole. In this report, the technique is described and the surgical experience for the first 13 patients is outlined. The immediate seizure relief with an average follow-up of 12 months was similar to that for patients with functional hemispherectomy, but the follow-up period for these 13 patients is not long enough to allow definite conclusions concerning long-term control of seizures and long-term complications.

Adolescent↗
PubMed1995

Association of venous and true arteriovenous malformation: a rare entity among mixed vascular malformations of the brain. Case report.

In this article the authors report the case of a mixed cerebrovascular malformation in which a true arteriovenous malformation (AVM), harboring a nidus, is associated with a venous malformation that serves as the draining vein for the nidus. Despite the authors' preoperative rationale for exclusive extirpation of the AVM, an inadvertent injury and the obliteration of the venous malformation generated delayed postoperative neurological deterioration, which could clearly be attributed to venous hemorrhagic infarction. Because this is only the second instance of this type of mixed vascular malformation of the brain reported, which also underscores the concept of nonsurgical treatment of venous malformations, the authors discuss the diverse literature regarding mixed vascular malformations and the treatment of venous malformations.

Abnormalities, Multiple↗
PubMed1995

Analysis of the neurofibromatosis 2 gene reveals molecular variants of meningioma.

There is evidence from cytogenetic and loss of heterozygosity studies for the involvement of a tumor suppressor gene on chromosome 22 in the formation of meningiomas. Recently, the NF2 gene, which causes neurofibromatosis type 2 and which is located in the affected region on chromosome 22, has been identified. A previous study on 8 of the 17 exons of the NF2 gene described mutations in 16% of meningiomas. We have analyzed the entire coding region of the NF2 gene in 70 sporadic meningiomas and identified 43 mutations in 41 patients. These resulted predominantly in immediate truncation, splicing abnormalities, or an altered reading frame of the predicted protein product. Although there was no evidence for distinct hotspots, all mutations occurred in the first 13 exons, the region of homology with the filopodial proteins moesin, ezrin, and radixin. The association of loss of heterozygosity on chromosome 22 with mutations in the NF2 gene was significant. These data suggest that NF2 represents the meningioma locus on chromosome 22. NF2 mutations occurred significantly more frequently in fibroblastic meningioma (70%) and transitional meningioma (83%) than in meningiothelial meningioma (25%), thus indicating a differential molecular pathogenesis of these meningioma variants.

Adult↗
PubMed1994

[Chronic mesenteric ischemia].

Thirty-four patients (twelve men, 22 women, mean age 53[16-71] years) with chronic mesenteric ischaemia were operated upon between 1979 and 1992. The most frequent symptom was loss of weight (50%) and postprandial pain (44%). The mean interval between onset of symptoms and diagnosis was 35 months. Angiography revealed disease of the coeliac trunk (CT) or the superior mesenteric artery (SMA) in 16 patients, of only the SMA in ten, and of only the CT in eight. Revascularisation was obtained with an autologous vein graft in 21 patients (on the TC in 12, AMS in nine), while transaortic endarterectomy was performed in 15 (on the CT in seven, the AMS in nine). There was one perioperative death. 20 patients were symptom-free 1-126 months after the operation, while five still had residual symptoms even though improved in three. Seven patients had a recurrence of symptoms, three immediately after operation and four after an initial symptom-free period. These results show that freedom from symptoms can be achieved even in advanced stages of chronic mesenteric ischaemia by reconstructive surgery of the intestinal and visceral arteries. However, residual symptoms that are possibly not of a vascular nature may persist after successful vascular reconstruction. Patients with recurrent obstruction may become symptom-free by repeat surgery even many years later.

Adolescent↗
PubMed1994

Deletion mapping of chromosome 19 in human gliomas.

There is evidence that a putative glioma tumor suppressor locus resides on the long arm of chromosome 19. We present data on 161 gliomas from 156 patients, which were studied by microsatellite analysis for loss of heterozygosity (LOH) on chromosome 19. Eight loci on the long arm and 2 loci on the short arm of chromosome 19 were examined. LOH on 19q was observed in 3/19 astrocytomas (WHO grade II), 12/27 anaplastic astrocytomas (WHO grade III), 16/76 cases of glioblastoma multiforme WHO (grade IV), 4/9 oligodendrogliomas (WHO grade II), 3/5 anaplastic oligodendrogliomas (WHO grade III), 5/9 mixed oligo-astrocytomas (WHO grade II) and 8/10 anaplastic oligo-astrocytomas (WHO grade III). While 31 of the tumors with LOH on chromosomal arm 19q exhibited allelic loss at every informative locus, 20 tumors showed terminal or interstitial deletions. In contrast to astrocytomas and glioblastomas, tumors with an oligodendroglial component had predominantly lost the entire long arm of chromosome 19. The common region of overlap in gliomas was located on 19q13.2-q13.4 between the markers D19S178 and D19S180. Our data confirm the involvement of a putative tumor suppressor gene on chromosomal arm 19q in gliomas and assign this gene to 19q13.2-q13.4.

Astrocytoma↗
PubMed1994

Quantitative and qualitative evaluation of patterns of cerebral language dominance. An amobarbital study.

As a part of presurgical evaluation, 173 patients received bilateral intracarotid amobarbital tests for determination of cerebral language dominance. Language testing during intracarotid amobarbital procedures (IAP) consisted of the following tasks: automatic speech, sentence comprehension, body commands, naming, repetition, reading, and spontaneous speech. Patterns of cerebral language dominance were evaluated and discussed on five levels of analysis: (1) quantification of language dominance on the basis of a lateralization index derived from the total language scores in each IAP; (2) determination of five dominance subpatterns (left or right dominant, strongly bilateral, and incomplete left or right dominant) according to quantification performed on level (1) and clinical judgement; (3) qualitative differentiation of three kinds of bilaterality (positive, negative, and general) according to total language performance in left and right IAP; (4) analysis of grouped linguistic subfunctions extracted from performance in specific IAP subtests; (5) extraordinary individual case histories. The distribution of lateralization indices revealed only partially continuous degrees of lateralization, especially between the left-dominant and bilateral subgroups. As for the clinically oriented classification, incomplete left dominance is frequent (16.2%), while incomplete right dominance does not occur at all. Atypical dominance patterns are mostly correlated to bilateral and/or extratemporal foci. Concerning grouped subfunctions, a rotated factor matrix statistic yields an analysis of clusters of IAP subtests, where functions involving expressive language capacities are separated from those that are purely receptive. Further analyses of bilaterality subpatterns suggest that there are mainly four bilaterality phenomena, namely interhemispheric dissociation, double representation, unilateral representation of subfunctions, and partial representation of subfunctions in either hemisphere. Application of these differentiations to individual cases yields additional evidence that can be used in patient selection for operation in order to avoid postoperative neuropsychological deficits, especially in candidates for extratemporal surgery. In conclusion, a multilevel analysis of IAP language data is recommended since it permits a detailed account of varieties of language dominance patterns and contributes to more adequate presurgical decision-making in planned operations in cognitively relevant brain areas.

Adolescent↗