Biomedical subjects

N Klug

Publications and source records attributed to N Klug.

At least 55 records · Page 3Linked to original sources

PubMed1998

Localization of language-related cortex with 15O-labeled water PET in patients with gliomas.

Measurement of relative cerebral blood flow (CBF) with 15O-labeled water PET has been widely used for brain mapping experiments on language functions in normal volunteers and patients with epilepsy. We focused on the question of whether PET during speech activation is an appropriate method for noninvasive determination of language-related cortex in patients with brain tumors. Furthermore, the suitability of the method for determination of hemispheric language dominance was examined and compared to the results of the Edinburgh Handedness Inventory. Ten right-handed and six left-handed patients with gliomas were examined prior to surgery while repeatedly performing word repetition and verb generation tasks. A set of volumes of interest (VOIs) was drawn on coregistered MRI in order to account for anatomic variability as well as anatomical alterations due to tumor mass effect. Repetition of nouns did not produce significant hemispheric differences. During stimulation by verb generation, reliable lateralized activations of Broca's area and supplementary motor area were detected in all right-handed patients. Of the left-handed patients, two showed clear right lateralization, two activated Broca's area bilaterally, and two had a pattern similar to that of right-handers. Patients with bilateral activations showed the strongest tendency toward bihandedness according to the handedness inventory. Lateralization of supplementary motor area in left-handers corresponded to lateralized activity in Broca's area. Tumors in the vicinity of language-related regions did not alter activation responses. In conclusion, measurement of CBF changes during verb generation permits identification of language-related areas in patients with gliomas with strong lateralization related to hemispheric dominance. These findings may be of particular clinical interest for left-handed patients.

Adult↗

PubMed1998

Somatostatin receptor imaging in intracranial tumours.

The somatostatin analogue [111In-DTPA-d-Phe1]-octreotide (111In-octreotide) allows scintigraphic visualization of somatostatin receptor-expressing tissue. While it is well known that a large variety of tissues express somatostatin receptors and 111In-octreotide scintigraphy has a clearly defined role in various neuroendocrine diseases, the clinical value of 111In-octreotide scintigraphy in brain tumours is still under clinical investigation. In 124 patients with 141 brain lesions (63 meningiomas, 24 pituitary adenomas, 10 gliomas WHO class I and II, 12 gliomas WHO class III and IV, 11 neurinomas and 2 neurofibromas, 7 metastases and 12 other varieties: three non-Hodgkin B-cell lymphomas, two epidermoids, one abscess, one angioleiomyoma, one chordoma, one haemangiopericytoma, one osteosarcoma, one plasmacytoma and one pseudocyst), 111In-octreotide scintigraphy was performed 4-6 and 24 h after i.v. injection of 110-220 MBq 111In-octreotide. Planar images of the head in four views with a 128x128 matrix and single-photon emission tomographic images (64x64 matrix) were acquired, and lesions were graded according to qualitative tracer uptake. Fifty-nine of the 63 meningiomas showed moderate to intense tracer uptake. Nine of 24 pituitary adenomas were visible; the remaining 15 did not show any tracer uptake. None of the class I and II gliomas with an intact blood-brain barrier were detected whereas 11/12 class III and IV gliomas showed 111In-octreotide uptake. None of the neurinomas or neurofibromas were positive. Five of seven metastases were classified as positive, as were the osteosarcoma, two of three non-Hodgkin B-cell lymphomas, one abscess, one angioleiomyoma, one chordoma and one haemangiopericytoma. The other varieties (one non-Hodgkin B-cell lymphoma, two epidermoids, one plasmacytoma and one pseudocyst) did not show 111In-octreotide uptake. The results demonstrate that a large variety of intracranial lesions express somatostatin receptors and therefore can be visualized by [111In-DTPA-d-Phe1]-octreotide scintigraphy. This technique can be valuable in the differentiation between meningiomas and pituitary adenomas, based on qualitative tracer uptake. [111In-DTPA-d-Phe1]-octreotide scintigraphy allows differentiation between meningiomas and neurinomas or neurofibromas and therefore provides complementary information to computed tomography or magnetic resonance imaging. Furthermore, this technique allows differentiation between scar tissue and recurrent meningiomas postoperatively and can help in non-invasive tumour differentiation of multiple intracranial lesions, which can be of value in defining the most adequate therapeutic strategy.

Adolescent↗

PubMed1998

Insulin-like growth factor binding protein-3 levels during early and late follow-up after surgery in acromegalic patients.

Disease activity in acromegaly is accurately reflected by growth hormone (GH) concentration during oral glucose tolerance test (OGTT) and insulin-like growth factor-I (IGF-I) levels, representing an integrated index of GH activity. This prospective study was performed to evaluate whether plasma IGF binding protein 3 (IGFBP-3) might also reflect the hormonal disease activity in pituitary acromegaly after operative treatment during early and late follow-up. Twenty-two acromegalic patients were studied. Data were obtained pre-, intra- and post-operatively in 13 cases. In 9 patients the acromegalic activity was studied only after treatment. The hormonal assessment included repeated blood samples for estimation of IGF-I, IGFBP-3 and repeated OGTTs. In each case 100 sigma g octreotide (Sandostatin lambda, Sandoz, Basel) was injected to test the acute response of GH, IGF-I and IGFBP-3. Intraoperatively, GH levels were estimated to examine acutely the influence of tumour reduction on GH levels. Patients were considered cured when GH levels (GH60min) were less than 2 ng/ml during OGTT 4 weeks after surgery. The data outlined that in patients with normalized GH60min levels, normalized IGFBP-3 levels were noticed 4 weeks and 12 months post-operatively. In non-cured patients normalized IGFBP-3 concentrations were found in 11 out of 15 cases in the late post-treatment phase. In contrast only 1 of 7 cured patients had persistently elevated IGF-I levels within the first month post-operatively, whereas no case of the non-cured patients had IGF-I values in the normal range. Despite these observations a strong correlation of IGF-I and IGFBP-3 did not exist before one year post-operatively -- either in the cured or in the non-cured patients. Serum IGFBP-3 in patients with pituitary acromegaly does not provide a predictive value of appreciable magnitude concerning cure or non-cure from the disease- whether examined early or late in the post-operative period. Absolute levels of IGFBP-3 may thus cause misinterpretation concerning cure of acromegalics after surgery.

Acromegaly↗

PubMed1998

Pressor and depressor responses in thermocoagulation of the trigeminal ganglion.

We have undertaken a retrospective analysis in 126 patients with trigeminal neuralgia on which a free-hand percutaneous thermocoagulation of the Gasserian ganglion was performed in our department. We focused on the occurrence of intraoperative vagal reactions, i.e. significant bradycardia and changes in blood pressure during the course of the procedure. Operative and anaesthetic records of patients who underwent the procedure were evaluated and correlated with clinical data from the patient's history. We observed the occurrence of vagal reactions i.e. significant bradycardia (< 50/min) or syncope in 20% of patients (p < 0.0002) during or immediately after penetration of the foramen ovale. No correlation between the operated side and the occurrence of vagal reactions was found. A significant rise in blood pressure levels (about 180 mmHg systolic) was observed in 36% of patients during thermocoagulation. We concluded that painful stimuli arising from lesioning in the course of the trigeminal nerve reach the mid-brain and may irritate the dorsal nucleus of the vagus nerve resulting in significant bradycardia or cardiac synode. To prevent haemodynamic deterioration i.v. atropine (0.5-2 mg) should be available when advancing the needle, while anti-hypertensive medication (Esmolol) may be needed during coagulation.

Blood Pressure↗

PubMed1998

Nasal muscle F-wave for peri- and intraoperative diagnosis of facial nerve function.

A new method for recording F-waves from facial muscles in order to assess the function of the intracranial and intracanalicular portion of the facial nerve peri- and intraoperatively has been developed: Direct (M) and F-responses were obtained from the nasal muscle after stimulation of the zygomatic branch of the facial nerve of healthy volunteers. We examined a number of patients with likely or obvious dysfunction of the facial nerve, mostly suffering from cerebellopontine angle (CPA) tumors. F-wave findings were compared to blink reflex and transcranial magnetoelectric evoked potential recordings, the latter obtained from the nasal muscle. The F-wave turned out to be a sensitive parameter for the diagnosis of facial nerve dysfunction. The feasibility of intraoperative nasal muscle F-wave recording and its prognostic value are demonstrated. The nasal muscle F-wave is considered to be a valid parameter for the diagnosis of clinically imperceptible facial nerve lesions, especially of its intracranial portion.

Brain Diseases↗

PubMed1997

Chronic subdural hematoma: surgical treatment and outcome in 104 patients.

BACKGROUND: The common occurrence of chronic subdural hematoma (CSDH) in older patients raises some diagnostic and therapeutic difficulties. Despite general agreement about the indication of operation, the extent of surgery is still discussed controversially. We have, therefore, reviewed operative findings and outcome in 104 patients with CSDH. METHODS: Retrospective analysis was performed by differentiating age < or = 60 years (n = 28) versus age > 60 years (n = 76) and burr hole craniostomy with a size range from 12-30 mm (n = 94) versus larger craniotomy (n = 10). All patients received closed-system drainage of the subdural space for 2-4 days. RESULTS: Four patients older than 60 years died within 30 days after surgery, two in each operative group. Excluding these postoperative deaths, 17 out of 92 patients (18.5%) after burr hole trepanation and one out of eight patients (12.5%) after craniotomy required reoperation due to rebleeding (n = 6), residual subdural fluid (n = 4), and residual thick hematoma membranes (n = 8). Eight patients, who had been initially treated by burr hole craniostomy despite preoperative detection of neomembranes by contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI), recovered without further intervention. Clinical outcome was good in both operative groups. The percentage of patients without or with only mild neurologic deficits at the time of discharge from the hospital was 72.3% in the burr hole and 70.0% in the craniotomy group, respectively. CONCLUSIONS: The clinical data of the present study suggest that burr hole craniostomy with closed-system drainage should be the method of choice for the initial treatment of CSDH, even in cases with preoperative detection of neomembranes. Craniotomy should be carried out only in patients with reaccumulating hematoma or residual hematoma membranes, which prevent reexpansion of the brain.

Adult↗

PubMed1997

The clinical and prognostic relevance of grading in intracranial ependymomas.

The clinical relevance of grading in ependymomas is almost always regarded as controversial. According to the classification of brain tumours revised by the World Health Organization (WHO) in 1993, brain tumours of ependymal origin are differentiated as subependymomas Grade I, ependymomas Grade II, and anaplastic (malignant) ependymomas Grade III. The purpose of the present retrospective study of 126 patients with intracranial ependymomas was to assess the clinical and prognostic significance of the topical classification and grading system by a uni- and multivariate statistical analysis. 87 Grade II ependymomas were predominantly located in the midline and in the fourth ventricle, whereas 39 anaplastic ependymomas Grade III were most often found in the cerebral hemispheres. Excluding the localization-linked operative mortality, progression-free survival (PFS) was significantly dependent on the histological grading. Median PFS time was 7.5 years in Grade II, but only 1.5 years in Grade III ependymomas. Stratifying for the two time intervals 1951-1970 and 1971-1990, and excluding the operative mortality, a multivariate Cox' model analysis of the covariates age, localization, grading, extent of surgery, and radiation therapy revealed that only the histological grading and radiation therapy had a significant impact on PFS. Thus, the WHO grading system has a statistically significant relevance for the long-term prognosis of intracranial ependymomas. However, the therapeutic management including radical tumour resection and additional local irradiation should be independent of the grading.

Adolescent↗

PubMed1997

Multimodal electrophysiological examinations in patients suffering from various tumors of the pineal region.

Multimodal electrophysiological examinations: blink-, glabella- and masseter-reflexes, as well as brain stem acoustic, somatosensory and visual evoked potentials were examined in thirteen patients with clear consciousness suffering from extra-axial, chronic, expanding processes in the tectal region. According to the data, the authors came to the conclusion that several modalities were often required to make a correct diagnosis or to the localization of the space occupying processes. Functional disturbances of the whole of the lower brain stem, but especially of the mesencephalon and of the lower pons were found in cases of expanding processes surrounding the tectum.

Adolescent↗

PubMed1996

Clinical relevance of somatostatin receptor scintigraphy in patients with skull base tumours.

The differential diagnosis of tumours in the skull base is often difficult. With the experience that various intracranial tumours differ in their expression of somatostatin binding sites (SBS) somatostatin receptor scintigraphy (SRS) with the somatostatin analogue octreotide can give additional information of the tumour entity. Seventy patients with various tumours of the skull base were examined with 111Indium-labelled DTPA-octreotide injected i.v.. Planar and tomographic images were obtained with a gamma camera 4-6 and 24 hours after injection. All of the meningiomas (unifocal and multifocal tumours in various locations) showed a high density of SBS whereas in none of the examined neurinomas SR were found. Pituitary adenomas revealed in only 50% SR in different concentrations and independent of the endocrine activity. SRS can help in the differential diagnosis between meningiomas and other tumours, postoperative scar or radionecrosis at the skull base. A dural infiltration with meningioma tissue ("meningeal sign") may be discriminated from a reactive hypervascularisation in lesions with a diameter > 0.5 cm. We conclude that SRS can offer additional diagnostic aspects in the pre- and postoperative management of patients with skull base tumours.

Adenoma↗

PubMed1996

Polyamine metabolism in gliomas.

Biosynthesis of the polyamines putrescine, spermidine, and spermine has been found to be activated in tissues with cellular proliferation. In the present study we have investigated polyamine levels and the activity of the first rate-limiting enzyme ornithine decarboxylase (ODC) in tumour samples obtained during operation of 202 patients with gliomas. Biochemical data were closely related to the grading of malignancy and to the morphological characteristics of each sample. Mean ODC activity was significantly higher in all gliomas as compared to peritumoural non-neoplastic brain. Furthermore, it was significantly higher (p < or = 0.001) in anaplastic gliomas who grade III and IV (9.0 +/- 9.6 nmol/g/h) than in gliomas WHO grade I and II (3.3 +/- 4.2 nmol/g/h). Highest enzyme activity (58.5 nmol/g/h) was found in solid and vital parts of malignant tumours, whereas predominantly necrotic areas exhibited low ODC activity (< 1 nmol/g/h). Thus, intra- and interindividual variability of ODC activity corresponded well to histomorphological heterogeneity in high-grade gliomas. Putrescine levels also increased with rising grade of malignancy, whereas spermidine and spermine levels did not correlate with the histological grading. In conclusion, high ODC activity represents a biochemical marker of malignancy in gliomas, but low values do not prove benignity. The present study reinforces the need of further and more extensive tumour sampling closely related to follow-up investigations in the heterogeneous group of gliomas.

Adolescent↗

PubMed1996

Prognostic relevance of localization and grading in intracranial ependymomas of childhood.

Intracranial ependymomas represent one of the most frequent brain tumors in childhood. Their preferred midline localization and their often controversially discussed classification prompted the present study of 67 intracranial ependymomas in children less than 15 years of age who were operated on from 1951 to 1990. Clinical data and follow-up of all children were retrospectively analyzed by calculation and statistical comparison of progression-free survival (PFS). According to the WHO classification as revised in 1993, 1 grade I subependymoma, 38 grade II ependymomas, and 28 grade III anaplastic (malignant) ependymomas were differentiated. Grade II ependymomas were predominantly located in the IV ventricle and in the supratentorial midline, which often made complete tumor resection impossible. In contrast, the majority of grade III tumors, most often situated in the cerebral hemispheres, could be totally removed. Operative mortality was higher in grade II than in grade III tumors. After recovery from operation, PFS was mainly determined by the histological grading. Median postoperative PFS was 120 months in grade II, but only 18 months in grade III ependymomas (P = 0.1417). Thus, despite varying therapeutic concepts, analysis of this 40-year collective study confirms the prognostic relevance of localization and WHO grading in the case of intracranial ependymoma in children.

Adolescent↗

PubMed1996

Diagnosis and staging of carpal tunnel syndrome: comparison of magnetic resonance imaging and intra-operative findings.

PURPOSE: In order to determine the reliability of magnetic resonance imaging (MRI) in the diagnosis and staging of carpal tunnel syndrome (CTS), the most common entrapment neuropathy, the following prospective study has been performed. METHODS: We compared clinical and electrophysiological studies in 58 cases of CTS with MRI investigations and confirmed the reliability by exact correspondence with intra-operative findings. RESULTS: Typical MRI characteristics of the median nerve in CTS have been established. There is a significant difference in flattening (p < 0.05), swelling (p < 0.01) and signal intensity (p < 0.05) of the median nerve between early and advanced CTS. Comparison of MRI and intra-operative findings revealed that median nerve compression was diagnosed correctly in 91% of cases. Additional lesions in the carpal tunnel, which are a primary cause of nerve compression, were established by MRI in 25 cases and confirmed by surgery. CONCLUSION: MRI is a reliable diagnostic tool for assessing as well as staging of CTS. Morphological changes following chronic nerve compression can be visualized. It is particularly useful in cases of suspected lesions within the carpal tunnel as a cause of CTS. The information provided may support the choice of adequate treatment modality.

Adult↗

PubMed1996

A case of delayed loss of facial nerve function after acoustic neuroma surgery.

We report on the uncommon delay of facial palsy in the course of a patient who underwent surgery for a left sided acoustic neuroma. Facial nerve function was preserved without clinical or electrophysiological deficit during the immediate postoperative phase and then lost almost totally over two days. This began on the seventh postoperative day. Recovery became visible under hypervolemic hemodilution and glucocorticoids a few days later and was complete after three months. Vasospasm in combination with neural edema might account for this uncommon delay of postoperative facial nerve deterioration.

Blinking↗

PubMed1996

F-wave recordings from nasal muscle for intraoperative monitoring of facial nerve function.

The generation of the F-wave in muscle after peripheral motor nerve stimulation depends upon the functional integrity of the entire motoaxon between its axon hillock and the motor endplates. Cerebellopontine angle (CPA) surgery bears the risk of damaging the facial nerve in its root exit zone; functional degradation should therefore be reflected by changes of the nasal muscle F-wave. Constant current pulses supraliminal for direct (M) muscular responses were applied subcutaneously to the zygomatic branch of the facial nerve ipsilateral to the operated side, EEG needle electrodes were placed in the nasal muscle and referred to glabella for recording of myoelectric activity. Anesthesia was achieved by application of fentanyl, midazolame and N2O and low doses of short acting muscular relaxants; the above-mentioned narcotics did not influence F-wave recordings, whereas the administration of muscle relax ants was often deleterious to F-wave monitoring. 22 patients with different tumors in the CPA, the cerebellum or the vicinity of the brainstem were subject to this monitoring procedure up to now. F-wave monitoring was effective in 12/22 cases. In 7/12 patients the signal was stable without any resulting dysfunction postoperatively. In 3/12 cases changes in amplitude and/or latency were observed indicating a subsequent facial palsy of a moderate degree. In 2 cases the F-wave was lost-these suffered from a facial paralysis afterwards. As an illustrative case the course of one of these is pointed out. In 10/22 procedures F-wave monitoring was ineffective due to the prolonged administration of muscle relaxants. The F-wave appears to be a valid tool for intraoperative prognosis of postoperative facial nerve function in CPA surgery. The borderlines of F-wave changes indicating damage to neural function by surgical manipulation are to be defined next.

Adult↗

PubMed1996

The acoustic evoked brainstem potential of the cat. An experimental study.

In 15 cats, the brainstem auditory evoked potentials were registered in far-field and near-field technique after surgical exposure of the rhomboid fossa. By alterations of the stimulus side and change in position of the registration electrodes on the one hand as well as by tract severance on the other hand, some interesting findings could be obtained never published before. Our investigations indicate that the far-field potentials registered from the scalp are generated axonally and constitute summation potentials of several generators. Accordingly, one should not refer to individual generators with regard to the scalp potentials, but rather to brainstem segments in which the individual potentials are generated.

Animals↗

PubMed1995

Multimodality electroneurophysiological findings in intra-axial and extra-axial lesions of the brain stem.

In 330 patients with a space occupying lesion of the posterior cranial fossa, the blink (BR) and masseter (MR) reflexes and brain stem auditory (BAEP) and somatosensory evoked potentials (SEP) were registered. The aim of our study was to look for electrophysiological criteria of differentiating between lesions within or outside the brain stem. The ipsilateral loss of BAEP in cerebellopontine angle tumours and the altered SEP in tumours within the brain stem turned out as frequent, almost specific findings. Prolonged ipsi-and contralateral late BR responses and prolonged MR responses, a long somatosensory central conduction time of the SEP and a prolonged wave III latency as well as a prolonged interpeak latency of the BAEP are not indicative but highly suspicious for a lesion within the brain stem. Prolonged early responses of the BR together with prolonged interpeak latencies of the BAEP are characteristic findings in cerebello-pontine angle tumours.

Blinking↗

PubMed1995

[Dura-plasty in intracranial operations].

Due to recent reports of slow-virus infections related to the use of lyophilized homologous grafts for duraplasty, we have reviewed the concept of dura substitution in cranial neurosurgery. The present study is based upon 2,115 cranial operations from 1991 to 1994. Frequency and complications of different grafts were investigated retrospectively. Within this time period, dura substitution was required with a frequency of 23.4%. In most cases, autologous tissue was used (47.5%), followed by lyophilized or dehydrated and gamma-radiated homologous cadaveric dura and fascia lata (41.8%). In addition, a synthetic polyesterurethane fleece was used since April 1994. In transsphenoidal approaches to the pituitary gland, autologous fascia lata with or without muscle was used exclusively (100%). In frontobasal trauma, plastic covering of the frontal skull base was performed predominantly by autologous galea-periost (84.8%). In contrast, homologous tissues were preferred for duraplasty in the posterior cranial fossa (77.9%). Complications, including CSF fistula, inflammation, pneumatocephalus, and pseudocysts were observed in 13.1% of operations with dura substitution. The rate of complications was highest in infratentorial (20.0%) and frontobasal operations (18.8%). Application of synthetic grafts for 9 months has reduced complications (6.3%). In conclusion, duraplasty should be generally performed by implantation of autologous grafts such as galea-periost or fascia lata. No restriction of this principle should be accepted for surgery in inflammation, after open brain injury, in the frontobasal region and in transsphenoidal approaches to the pituitary gland. In all other cases, insertion of synthetic grafts seems to be equal to the use of autologous tissue, and even superior in large dural defects.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological Dressings↗

PubMed1994

High sensitivity of the in vivo detection of somatostatin receptors by 111indium (DTPA-octreotide)-scintigraphy in meningioma patients.

The recent availability of isotope-labelled somatostatin analogues has allowed one to detect somatostatin receptors in normal tissue as well as in endocrine or non-endocrine cranial tumours. The purpose of the present study was to establish the value of somatostatin receptor scintigraphy using an 111Indium-labelled somatostatin analogue, octreotide, in the diagnostic work-up of meningioma patients. Twenty-two patients (16 women, 6 men, aged from 19-70 years) with newly diagnosed, residual or recurrent cranial meningiomas were examined. 111Indium-labelled DTPA-octreotide was injected i.v.. Planar and tomographic images were obtained with a gamma camera 4-6, and 24 hours after injection. In all of the meningiomas studied a high density of somatostatin receptors was detected by scintigraphy. No false negative test result was found. Due to this, a 100% predictive value of a negative test was calculated. However, when the tumours were taken in culture differing staining intensity could be seen in the light- and electron microscopic level even on individual cells of a single culture when silver intensified somatostatin-gold was used as ligand. We conclude, that in vivo somatostatin receptor scintigraphy may aid in the pre-operative differential diagnosis of skull base tumours.

Adult↗