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Biomedical subjects

K Roosen

Publications and source records attributed to K Roosen.

At least 73 records · Page 4Linked to original sources
PubMed1996

Prognostic significance of nuclear DNA content in human meningiomas: a prospective study.

Flow cytometric DNA analyses were performed to study the correlation between alterations of nuclear DNA content and clinical aggressive tumour behaviour in 134 cranial meningiomas. Forty-one meningiomas revealed an aneuploid DNA content with a distribution of n = 24 in benign, n = 12 in atypical and n = 5 in anaplastic tumours. Aneuploid DNA content was correlated with a significantly higher amount of histomorphological criteria like evidence of mitoses, necrosis, infiltration and increased cellularity. There was a significantly higher Ki 67 proliferation index in the aneuploid meningiomas in comparison to the diploid tumour group. The rate of aneuploid cell-lines was increased in recurrent tumours. No tumour recurrence could be found in diploid meningiomas during follow up (mean 37 months, range 22-46 months). However eight of forty-one aneuploid tumours showed meningioma recurrence. Nuclear DNA content has an important significance in predicting risk of recurrence and poor clinical outcome after benign meningioma surgery.

Aneuploidy↗
PubMed1996

Factors influencing morbidity and mortality after cranial meningioma surgery--a multivariate analysis.

In a retrospective analysis 385 patients with a histologically defined cranial meningioma were studied to analyze the impact of characteristic factors on morbidity and mortality after modern cranial meningioma surgery. Mortality was 4.2% one month and 7.3% six months after operation. 15.6% of the patients stayed more than one month in the hospital (defined as criteria of operative morbidity). Age, poor preoperative clinical condition (ASA score), intra- and postoperative bleeding and CSF disturbances were significantly associated with a subsequent decrease of quality of life. First symptoms like intracranial hypertension, seizures, aphasia and hemiparesis were correlated with an increase of postoperative Karnowsky index. Postoperative quality of life decreased in patients with optic and other cranial nerve disturbances significantly. Tumour size, location (exception: medial sphenoid wing) and histological diagnosis did not influence surgical outcome. This information may be useful in management decisions regarding asymptomatic meningiomas in elderly and high risk patients.

Adolescent↗
PubMed1996

Progesterone receptors in tumor fragment spheroids of human meningiomas.

Progesterone receptors (PgR) are detectable in about 60-70% of tissue specimens of human meningiomas. Despite these data, PgR are hardly to be found in monolayer tissue culture of meningiomas. Aim of this study was to elucidate whether PgR might be preserved in tumor fragment spheroids of meningiomas maintained in organ culture since the morphological appearance of the original tumor is preserved by this culture technique. Aliquots of meningioma specimens of 25 patients (17 females) were snap frozen in liquid nitrogen immediately after removal. Additionally, monolayer tissue cultures of the same specimen were obtained as primary culture and passage #3. Tumor fragment spheroids were kept on medium-agar with liquid medium overlay and harvested after 1 and 3 weeks in culture. PgR were detected by immunohistochemistry using a rat monoclonal antibody. 18/25 meningioma tissue specimens were positive for PgR. In 8 out of 15 PgR-positive tumors which formed spheroids we could detect PgR in fragment spheroids after 1 and 3 weeks in culture. In contrast, none of the monolayers depicted PgR. PgR is preserved in a considerable amount of tumor fragment spheroids of PgR-positive meningiomas. They remain detectable after 3 weeks of culture whereas monolayer tissue cultures are PgR-negative. Thus, tumor fragment spheroids seem to be a suitable tool to investigate progesterone/antiprogesterone effects in vitro.

Adult↗
PubMed1996

Correlation of intra-operative ultrasound with histopathologic findings after tumour resection in supratentorial gliomas. A method to improve gross total tumour resection.

The aim of this study was to evaluate whether intra-operative ultrasound (= IOUS) is a suitable tool to detect residual tumour tissue after gross total resection in supratentorial gliomas. During a period of 18 months 45 patients with supratentorial gliomas (38 high-grade and 9 low-grade, according to the WHO-grading system [42]) were operated on. A series of 78 biopsies was taken from the resection cavity under continuous sonographic control at the end of surgery. Gross total tumour resection was intended in 34 patients (= 76%). The biopsy specimens were matched with the sonographic features at each biopsy site. The sonographic appearance of the resection margins were classified into 2 groups: (1) Irregular hyperechoic areas extending from the cavity into the iso-echogenic brain tissue and (2) a dense small (< or = 3 mm in diameter) rather regular hyperechoic rim surrounding the resection cavity. 47 out of 53 biopsies taken from hyperechoic areas (group I) (36 high-grade/11 low-grade) revealed solid tumour tissue (= 89%). 34 (= 72%) of these 47 areas were microscopically assessed as inconspicuous by the surgeon. 6 samples (4 high-grade/2 low-grade) contained tumour infiltration zone. 25 biopsies (23 high-grade/2 low-grade) taken from the hyperechoic rim [group 2] were diagnosed as follows: Normal brain tissue in 11, tumour infiltration zone in 8 and solid tumour tissue in 6 cases. Of 34 cases with "gross total removal" according to the surgeon's assessment 25 showed sonographic signs of residual tumour tissue, which was confirmed histologically as solid tumour tissue in 22 of these cases. It is concluded, that IOUS following resection of supratentorial gliomas can detect residual tumour tissue with high specificity and thus improve gross total resection. However, a thin hyperechoic rim surrounding the resection cavity (less than 3 mm in diameter) is a non-specific finding, which can mask thin residual tumour layers and therefore needs further evaluation of its nature.

Biopsy↗
PubMed1996

Brain tissue pO2 in relation to cerebral perfusion pressure, TCD findings and TCD-CO2-reactivity after severe head injury.

As a reliable continuous monitoring of cerebral blood flow and/or cerebral oxygen metabolism is necessary to prevent secondary ischaemic events after severe head injury (SHI) the authors introduced brain tissue pO2 (ptiO2) monitoring and compared this new parameter with TCD-findings, cerebral perfusion pressure (CPP) and CO2-reactivity over time on 17 patients with a SHI. PtiO2 reflects the balance between the oxygen offered by the cerebral blood flow and the oxygen consumption by the brain tissue. According to TCD-CO2-reactivity PtiO2-CO2-reactivity was introduced. After initially (day 0) low mean values (ptiO2 7.7 +/- 2.6 mmHg, TCD 60.5 +/- 32.0 cm/sec and CPP 64.5 +/- 16.0 mmHg/, ptiO2 increased together with an increase in blood flow velocity of the middle cerebral artery and CPP. The relative hyperaemic phase on days 3 and 4 was followed by a decrease of all three parameters. Although TCD-CO2-reactivity was except for day 0 (1.4 +/- 1.5%), sufficient, ptiO2-CO2-reactivity sometimes showed so-called paradox reactions from day 0 till day 3, meaning an increase of ptiO2 on hyperventilation. Thereafter ptiO2-CO2-reactivity increased, increasing the risk of inducing ischaemia by hyperventilation. The authors concluded that ptiO2-monitoring might become an important tool in our treatment regime for patients requiring haemodynamic monitoring.

Adolescent↗
PubMed1996

Primary Ki-1-positive T-cell lymphoma of the brain--an aggressive subtype of lymphoma: case report and review of the literature.

BACKGROUND: By detection of the Ki-1 antigen, Stein (1985) defined a new entity of anaplastic large cell lymphoma [24]. Apart from our case, only four further cases of Ki-1 positive primary central nervous system lymphoma (PCNSL) have been reported in the literature to date. CASE REPORT: A 63-year-old man presented with two frontal and parietal mass lesions and one ring lesion on computed tomography scan. Clinically, no evidence of brain metastases or abscesses could be found. Immunohistochemical investigations of biopsy specimens revealed a large cell anaplastic T-cell lymphoma positive to Ki-1 antigen. In spite of all therapeutic efforts, the patient died less than 3 months after the onset of symptoms. DISCUSSION: In all cases the clinical course was very rapid, suggesting that Ki-1 positive PCNSL might form an aggressive subtype of lymphomas. Since the radiologic appearance was atypical and clinical diagnosis was not possible, diagnostic biopsy for immunohistochemical diagnosis should be performed.

Brain Neoplasms↗
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

Critical increase of blood flow velocities after subarachnoid haemorrhage: vasospasm versus hyperaemia.

Thirty cases of subarachnoid haemorrhage (SAH), who underwent early aneurysm clipping, were studied to clarify the significance of a critical increase of blood flow velocities in correlation to neurological disability and cerebral blood flow. Three different groups of patients could be distinguished: 57% (17) of the cases showed increased TCD-values at the affected side corresponding to secondary neurological deficits (Vasospasm-group). The CBF-results pointed out a side difference according to the flow acceleration. In 7 patients (23%) we detected a similar side difference in blood flow velocity, but no secondary deficit appeared. The corresponding CBF-measurements showed risen values with no side difference (Hyperaemia-group). The third group of patients (20% i.e.6 cases) developed neurological deficits and corresponding side difference in CBF-measurements, but the transcranial Doppler sonography could not detect a significant side difference and even showed normal values (Blind-TCD-group). Critical increased blood flow velocities after SAH without secondary neurological deficits does not indicate vasospasm but hyperaemia.

Adult↗
PubMed1996

Transcranial duplex-sonography in intracranial hemorrhage. Evaluation of transcranial duplex-sonography in the diagnosis of spontaneous and traumatic intracranial hemorrhage.

The aim of this prospective clinical study was to evaluate the potential of bedside transcranial color-coded duplex sonography (TDS) in the assessment of patients with acute intracranial hemorrhage and respective complications. 74 patients (35 with spontaneous and 27 with traumatic hemorrhage, 12 excluded due to insufficient insonability) underwent 152 TDS examinations. The results were compared to computer-tomography (CT) as well as conventional transcranial Doppler sonography (TcD). The size and localisation of intracerebral hemorrhages as detected in TDS coincided in 39/42 examinations with CT findings; in cases of traumatic intracranial extracerebral hematoma TDS correlated in all but one case (18/19). The TDS findings for the diameter of third and lateral ventricles (n = 126) as for midline-shift (n = 26) showed a good correlation (p < 0.0005) to CT-measurements. TDS appears to be a useful bedside, non-invasive tool in order to detect and exclude intracranial complications in patients with intracranial hemorrhages.

Cerebral Hemorrhage↗
PubMed1996

Continuous monitoring of brain tissue PO2: a new tool to minimize the risk of ischemia caused by hyperventilation therapy.

Secondary ischemic events worsen the outcome of patients with severe head injury. Such a secondary ischemic event may be caused by a forced hyperventilation. A consequence of the induced vasoconstriction is the risk of ischemia with an adverse effect on outcome. As a reliable and on-line technique, brain tissue pO2 (p(ti)O2) is used for monitoring regional microcirculation, to detect critical hypoperfusion. On 22 patients with a severe head injury 70 hyperventilation tests were performed from day 0-9 after trauma, calculating TCD-CO2-reactivity (% change of mean flow velocity per mm Hg paCO2 change). Additionally brain p(ti)O2-CO2-reactivity (% change of brain p(ti)O2 per mm Hg paCO2 change) was calculated and introduced. Group A +2 (p(ti)O2 < or = 15 mm Hg, TCD-CO2-reactivity > or = 2.5%, p(ti)O2-CO2-reactivity > 0%) and group B +2 (p(ti)O2 > 15 mm Hg, TCD-CO2-reactivity > or = 2.5%. p(ti)O2-CO2-reactivity > 0%) was formed. P(ti)O2 values in group A+2 decreased to an ischemic level or ischemia aggravated during hyperventilation. In group B+2 no ischemic events occurred. TCD-CO2-reactivity, p(ti)O2-CO2-reactivity and decrease of paCO2 were not significantly different in both groups. 6 out of 22 patients showed, from day 0-9, at least once a risk of (aggravating) ischemia by hyperventilation therapy.

Brain↗
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↗
PubMed1995

Differential effects of vincristine and phenytoin on the proliferation, migration, and invasion of human glioma cell lines.

The aim of this study was to investigate the antimigratory and antiinvasive potential of vincristine sulfate (VCR) on human glioma cells and to analyze whether phenytoin (5,5-diphenylhydantoin; DPH) might act synergistically with VCR. Vincristine affects the cytoplasmic microtubules; DPH has been reported to enhance VCR cytotoxicity in murine cells. In two human glioma cell lines, GaMG and D-37MG, we found VCR to reduce monolayer growth and colony formation in a dose-dependent fashion at concentrations of 10 ng/ml and above. Phenytoin increased the cytotoxic and cytostatic effects of VCR in monolayer cells but not in spheroids. Multicellular spheroids were used to investigate directional migration. A coculture system of GaMG and D-37MG spheroids with fetal rat brain aggregates was used to analyze and quantify tumor cell invasion. A dose-dependent inhibition of migration and invasion by VCR was observed in both cell lines without further enhancement by DPH. Immunofluorescence microscopy with antibodies against alpha-tubulin revealed dose-dependent morphological alterations in the microtubules when the cells were exposed to VCR but not after incubation with DPH. Based on the combination of standardized in vitro model systems currently in use and the present data, the authors strongly suggest that VCR inhibits migration and invasion of human glioma cells. This is not altered by DPH, which inhibits cell proliferation in combination with VCR.

Antineoplastic Agents↗
PubMed1994

Vascularization of primary central nervous system tumors: detection with contrast-enhanced transcranial color-coded real-time sonography.

PURPOSE: To study the potential of contrast material-enhanced transcranial color-coded real-time sonography (TCCS) in detection of primary intracranial tumor vascularization. MATERIALS AND METHODS: Primary central nervous system (CNS) tumors in 28 patients were examined with TCCS before and during administration of a transpulmonary, stable, galactose, microparticle-based ultrasound (US) contrast agent. All patients underwent cranial computed tomography and magnetic resonance imaging; nine patients also underwent intraarterial digital subtraction angiography. RESULTS: All lesions were hyperechoic on B-mode US scans except one grade 2 astrocytoma. The location and extent of hyperechoic lesions correlated well with findings on CT scans and MR images. After injection of contrast material, color Doppler flow signals were seen in nine of 14 low-grade lesions and 14 of 14 high-grade lesions. High-grade malignant tumors always had atypical arterial and venous Doppler spectra with irregular distribution of Doppler shift and signal intensities; these atypical flow patterns were also detected in some low-grade tumors. CONCLUSION: In addition to depiction of primary CNS tumors in B-mode, contrast-enhanced TCCS enables evaluation of vascularization associated with tumor parenchyma.

Adult↗
PubMed1993

Studies of tissue PO2 in normal and pathological human brain cortex.

Brain cortex PO2 was measured after craniotomy and opening of the dura mater in 26 patients. We determined the brain tissue PO2 under standard narcotic conditions and after changing arterial PO2 and PCO2. Patients were divided into two groups (normal and pathological), depending on the aspect of their cortex on Ct/MRI and intraoperative appearance of the cortex. No statistical significantly difference was seen between tissue PO2 of the normal and the pathological group. A significant difference was seen only between the normal group and a subgroup with brain swelling (p = 0.0344). In the normal group no correlation was seen between tissue PO2 and arterial PO2 (r = 0.1541, p = 0.3076), whereas in the pathological group and especially in the oedema subgroup there was a highly significant correlation between tissue PO2 and PaO2 (r = 0.754, p = 0.0015 and r = 0.888, p = 0.0007). Breathing 100% oxygen changed tissue PO2 to 137.8 or 352 mmHg in the normal or the pathological group, respectively. Again, there was no correlation between tissue PO2 and PaO2 in the normal group (r = 0.1071, p = 0.392), whereas this correlation was significant in the pathological and the oedema subgroup (r = 0.6291, p = 0.0473 and r = 0.8385, p = 0.0185). This is evidence for regulatory mechanisms of tissue PO2. During hyperventilation no significant difference in tissue PO2 between the normal and the pathological group was seen. Low tissue PO2 values, however, indicate a risk for inducing ischemia.

Adult↗
PubMed1993

[Ventral or dorsal spondylodesis in dens basal fracture--a new classification for choice of surgical approach].

The conservative treatment of the fracture of the densbasis (type 2 according to Anderson and D'Alonzo) bears the risk of developing a pseudarthrosis in about 30%. Therefore the anterior screw fixation according to Magerl/Böhler is general accepted. When the fracture line runs from top back to front base in this method the risk of developing a pseudarthrosis increases. With an own classification in accordance to the run of fracture line type A, B and C is differentiated. In Type A and B the anterior screw fixation is recommended. In case of type C the posterior fusion of the arches C1 and C2 is biomechanically more advisable--it results an axial compression on the fracture fissure. The usefulness of the classification is demonstrated with clinical cases.

Adult↗