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Biomedical subjects

V Bockermann

Publications and source records attributed to V Bockermann.

15 recordsLinked to original sources
PubMed2001

A pair of clamps for a safe removing and repositioning of beta and gamma angular settings of Brown-Roberts-Wells stereotactic system during operation.

The Brown-Roberts-Wells arc system is a non-target-centered design, i.e., without an independent approach angle. The approach angle of this system strictly depends on precalculated values (entry and target point). Therefore, some components of the system used sometimes prevent a direct insight into the operation field. Once the entry point has been set, the arc system normally has to be taken off to permit an unimpeded approach to the burr hole. To facilitate rotation and return to the primary beta and gamma angular settings during stereotactic craniotomy and other surgery, a pair of clamps was designed for the BRW arc system. These clamps help the approach to the entry point in such a way that some components of the arc (e.g., the guide block holder) are removed from the surgical field, thus giving wide visual access for the stereotactic approach. Consequently, it is no longer necessary to remove the entire arc system, resulting in an increased operation safety and shorter operation times.

Equipment Design↗
PubMed1998

A new forceps for the safe and easier insertion of subdural catheter: technical note.

A new forceps suitable for the safe and easier insertion of a silicon catheter into the subdural space is described. The use of this new tool has two advantages: Firstly, the insertion of the silicon subdural catheter is parallel to the brain surface and secondly, the movement of the catheter's end in the subdural space is controlled with greater accuracy. Thus, the surgeon has the opportunity to direct the catheter to the right position avoiding penetration or injury of the brain.

Catheters, Indwelling↗
PubMed1998

MiniMATCH: a simple method for local data transfer between MRI and CT scan sets.

A comparison of the spatial position of distinct locations within cranial MRI and CT scan sets can easily be done with a simple algorithm designed as a computer program. After determination of a basic system formed by the coordinates of anatomical landmarks in CT and MRI, arbitrary points can be identified on one scan set and transferred quantitatively to the other. Pros and cons of the method are discussed and opposed to the properties of specifically designed image processing systems.

Algorithms↗
PubMed1997

Determination of the burr hole-site using the Brown-Roberts-Wells stereotactic system. A simple marking technique: technical note.

The authors describe a new tool-set with which the determination of the burr hole-site using the BRW-stereotactic system can be done on a non-sterile-washed head. The described attainment permits an increased security, not only reducing exposure of the operative field to a minimum but also shortening the operative length. The use of this tool-set for marking smaller superficial cortical processes is also possible.

Computer Simulation↗
PubMed1996

Atypical and malignant meningiomas: evaluation of different radiological criteria based on CT and MRI.

The following are our results of a retrospective analysis of 214 patients, operated on meningiomas, in order to investigate radiological criteria of malignancy. Among these cases there were 31 patients with a histologically confirmed diagnosis of malignant subtypes. As uncertain signs of malignancy of ensuing radiological features are an irregular enhancement of contrast-media and the size of cerebral edema. Based upon CT and MR images we have developed a standardised, computerised evaluation method which enables us to study in detail the internal architecture of meningiomas.

Adult↗
PubMed1995

[Implantation of a phrenic stimulator in central respiratory paralysis].

Neoplastic or traumatic lesions of the brain stem or the upper spinal cord frequently cause respiratory insufficiency necessitating permanent mechanical ventilation. If the integrity of the diaphragm and its nerves is not affected, adequate ventilation can be achieved by electric stimulation of the phrenic nerves. Diaphragm pacing systems mean the patients can be independent of ventilator treatment. This is a psychological advantage for the patient, giving him or her the option of living in less specialized medical care units and perhaps even at home. CASE REPORT. We report the case of a 47-year-old man with a brain stem tumour, which was resected in large pieces. During the postoperative period an increasingly severe respiratory insufficiency developed, which finally made continuous mechanical ventilation necessary. After the viability of the phrenic nerves and contractility of the diaphragm had been shown by direct stimulation of the nerves to be still intact, it was decided that a diaphragm pacer system should be implanted. A "Diaphragm Pacer System S232 G" (Avery Laboratories, Glen Cove, N.Y., USA: external transmitter, antenna, implanted electrode and receiver) was implanted. Using a supraclavicular approach, phrenic nerve electrodes were placed around each nerve and connected with subcutaneous implants of radio signal receivers. Six days after implantation phrenic nerves were stimulated for a first short period. External antenna loops were taped to the skin over the implanted receiver sites (Fig. 3). The impulses produced by the transmitter were delivered via these antenna loops and led to contraction of the diaphragm, providing almost normal respiration. The duration of stimulation was increased stepwise from 1 h a day to full-time stimulation. Three weeks after implantation of the diaphragm pacer system the patient could be totally weaned from mechanical ventilation. After a further 2 weeks it was possible to discharge him from the intensive care unit, and he was then transferred to a rehabilitation centre.

Brain Neoplasms↗
PubMed1989

[Microsurgical resection of small brain tumor processes with stereotactic control].

From 1986 we have operated upon 13 patients with small neoplasms localised deep intracerebrally or subcortically in the central region with stereotactic guidance. Exact localisation of the tumour was one aim, whereas another one was to avoid damaging functionally important structures. In the first two patients we performed stereotactic marking of the tumour after craniotomy. The following procedure was found to be particularly useful: - determination of the tumour coordinates and planning of the approach - approach by means of a stereotactically guided probe, if necessary biopsy - stereotactically guided introduction of the leading catheter - removal of the stereotactic frame and bedding of the patient - craniotomy and microsurgical resection of the tumour This surgical procedure may be performed in one or two separate sessions. The accuracy of microsurgical tumour resection achieved by stereotactic means resulted in a remarkable reduction of postoperative neurological deficits.

Adult↗
PubMed1989

[Application of digital image processing techniques in cephalometry].

Digital image processing methods were applied to cephalometric analysis. Conventionally taken x-rays were captured by the aid of a video-camera. Digital processing was done using the IPS-System (Kontron). The resulting average error of the method at this stage of development was comparable to that of the traditional method using a light box.

Cephalometry↗
PubMed1988

Impulse cytophotometric DNA analysis in pituitary adenomas.

Flow cytometric DNA analysis was carried out on 32 microsurgically removed pituitary adenomas. Additionally, the histograms of tumor cell nuclei of 7 patients were compared with those of the cultured cells from the same tumor samples. The tumors were classified into 3 groups according to the proliferation index (PI) of the flow cytometric results: 1) tumors with DNA patterns of slow proliferation (PI under 10), to which the majority of the examined pituitary adenomas belonged; 2) pituitary adenomas with diploid karyograms and PI values from 10 to 15; 3) diploid or aneuploid karyograms with PI values above 15. The third group were characterized histologically by increased chromatin content, nuclear polymorphism, mitoses, and extrapituitary infiltration of the tumor cells, and were, therefore, no longer benign. However, there was no direct relationship between the intensity of hormone secretory activity of the tumors and DNA ploidy. Cultured adenoma cells examined by flow cytometry remained stable in all cases but one.

Adenoma↗
PubMed1988

[An applicator for the implantation of I125 seeds for interstitial therapy of brain tumors].

A compact magazine has been developed allowing a quick and easy implantation of I-125 seeds in interstitial therapy of intracranial tumors. The magazine is made of steel and has the shape of a right parallelepiped. One seed can be put each time into a movable insert. The magazine is connected to a normal application canula. It is easy to handle and contributes much to radioprotection.

Brachytherapy↗
PubMed1987

Five-and-a-half years' experience with percutaneous retrogasserian glycerol rhizotomy in treatment of trigeminal neuralgia.

The results of treating trigeminal neuralgia with percutaneous retroganglionic glycerol rhizotomy in 319 patients from an overall series of 394 patients with 459 operations carried out over a period of 5 1/2 years are reported. Idiopathic trigeminal neuralgia was the diagnosis in 252 patients. 34 patients had trigeminal neuralgia associated with multiple sclerosis. The remaining 33 patients suffered from symptomatic trigeminal neuralgia or atypical facial pain. 230 patients (91.3%) with idiopathic trigeminal neuralgia and 30 patients (88.2%) with multiple sclerosis reported complete freedom from pain. In 12 patients (4.8%) of those with tic douloureux and in 1 patient (2.9%) with multiple sclerosis, pain was alleviated, and the patients required a reduced pharmacotherapy. 10 patients (3.9%) and 3 patients (8.8%) were considered to be treatment failures. The rate of recurrences within the first 2 years was 10.9 and 40.0%, respectively. In the long-term, the rate of recurrences in patients with tic douloureux was 36.9%. 144 patients (45.1%) noticed a hypesthesia. 132 patients (41.4%) had hypalgesia following the procedure, and there was a decrease of symptoms in the long-term observation in 20.0% of the patients. 59 patients (18.5%) developed dysesthesia postoperatively which regressed only to an inappreciable extent in the long-term course. In 16 patients (5.0%) exclusively with a preexisting organic lesion or who had received surgical pretreatment, there was a loss of corneal sensation. The investigation showed on the one hand the effectiveness of the method, but on the other hand also the possibility of marked sensory disorder in selected cases.

Administration, Cutaneous↗
PubMedDate not supplied

Expression of nitric oxide synthase isozymes (NOS I-III) by immunohistochemistry and DNA in situ hybridization. Correlation with macrophage presence, vascular endothelial growth factor (VEGF) and oedema volumetric data in 220 glioblastomas.

BACKGROUND: Nitric oxide (NO) is synthesized from arginine by three different isozymes of nitric oxide synthase (NOS I-III). NO has been identified as a powerful metabolite of vascular smooth muscle cell function, cerebral blood circulation and oedema induction. NOS induction by different cytokines has been shown previously in glioblastoma cell cultures and NOS III expression due to astrocytoma grading has been shown in several tumors recently. The aim of the present study was to study the coexpression of NOS I-III, macrophage and capillary presence with VEGF, EGF and their receptors and to investigate a possible mechanism in peritumoral oedema generation. MATERIALS AND METHODS: We have investigated the expression (4-grade values, blinded assay by two observers) of NOS I-III together with those of VEGF, VEGF- R (Flt-1), EGF-R1, von-Willebrand-factor (VWF) and a pan-macrophage marker (Ki-M1P) immunohistochemically in tumor specimens from 220 patients and performed tumor volume morphometry by image analysis in a subgroup of 32 cases to test for any correlation with the peritumoral oedema volumes. Inducible NOS II was further investigated by in situ labelling with a DNA oligonucleotide probe cocktail. RESULTS: All of the specimens revealed some NOS expression, NOS II was expressed in macrophages, microglia and endothelial cells, NOS III and I was localized in glioblastoma cells, NOS III in endothelial cells as well. The highest degrees of expression were observed in 46% (NOS I), 22% (NOS II) and 75% (NOS III) of all specimens. Inducible NOS II in any expression grade was observed in 47.5% of the specimens. Significant correlations were observed for the expression of the macrophage marker Ki-M1P with NOS II (p = 0.024), endothelial NOS III with NOS I (p = 0.0003), VEGF-R1 with NOS II (p = 0.0008) and NOS III (p = 0.011) The oedema volumes could not be correlated significantly with NOS or VEGF-R1 expression values but with those of endothelial staining (p = 0.02). We observed a trend towards higher Ki-M1P expression values together with higher oedema volume extensions. In situ hybridization demonstrated reaction products in endothelial and perivascular regions and sometimes scattered throughout the specimens revealing the labelling of macrophages. CONCLUSIONS: The main source of NO is NOS I and NOS III. The latter is located in endothelial cells and glioblastoma cells. The expression of NOS II in glioblastomas is restricted to infiltrating macrophages. NOS II and III expressions were observed significantly together with that of VEGF-R1. Neither NOS I-III nor VEGF-R expression could be correlated with the extension of the peritumoral oedema.

Antibodies, Monoclonal↗
PubMedDate not supplied

Oedema extension in cerebral metastasis and correlation with the expression of nitric oxide synthase isozymes (NOS I-III).

BACKGROUND: The development of a peritumoral oedema is a common radiological sign in preoperative CT- and MRI scans of patients with cerebral metastasis. Large tumours can be accompanied by a marginally extended oedema and vice versa. Several cytokines (VEGF) have been identified as mediators of vascular induction and permeability. Transmitters such as nitric oxide (NO) have been identified as specific mediators of vascular dilation and tumour blood flow in primary brain tumours in which different NOS isozymes (NOS I and III) are induced as a result of the latent hypoxic metabolic scenery. Other authors have considered NO as an endothelial stabilising metabolite. Inducible NOS II is expressed by microglia and macrophages invading during tumour growth. At present, no data exist on NO synthesising enzymes in cerebral metastasis. MATERIALS AND PATIENTS: Cryosections (N = 96) of metastatic resections were investigated immunohistologically using a 4-step grading evaluation for the expression of NOS I-III, VEGF-receptor FLT-1, a pan-macrophage marker Ki-M1P, and capillary vessel presence by endothelial Von-Willebrand-Factor staining. The tumour and oedema extension was measured in preoperative MRI scans by an image processing device (Kontron) and calculated for the ratios of oedema volumes to total tumour volumes. The data were analysed statistically (Pearson Chi2 and Kruskal-Wallis analysis of variances) and correlated with the clinical data. Inducible NOS II was further investigated by in situ hybridization with a (4x30 mer) DNA oligoprobe cocktail. RESULTS: Between 1987 and 1996 289 patients in our department suffered from a metastatic disease in the brain or spinal cord. In 96 cases resected tumour material was processed for the immunohistological investigation. The age distribution ranged from 14 to 85 years with a median age of 58 years. The mean duration of symptoms before diagnosis was estimated as 53 days. The expression of NO synthase was frequently observed. NOS I was detected in 83.6%, gradings 2 and 3 in 40.5% of them. NOS III, the endothelial isoform, was observed in 39.4% (gradings 2 and 3), inducible NOS II in 29.4% (grading 2 and 3) of the specimens. The VEGF receptor FLT-1 could be detected in 70% of them, 24% in higher expression 2 and 3. The pan macrophage marker Ki-M1P was observed in 72% of all cases. Fifty seven percent of the specimens exhibited strong labelling with antibodies against VWF. Coexpressions were statistically significant for the VEGF receptor and NOS I-III (p < 0.01), Ki-M1P and NOS I and II (p < 0.05). A negative correlation was detected for the oedema index (oedema volume/total volume) and the labelling data for NOS III (r = -0.44, p = 0.13) and VEGF-R (r = -0.42, p = 0.022). No correlation existed for Ki-M1P, VWF and NOS I. CONCLUSIONS: The objective of the study was to investigate oedema morphometry, expression of NOS I-III and VEGF-R, presence of capillary vessels and macrophages in cerebral metastasis. A further aim was to investigate a putative oedema induction by NO producing isozymes. Nitric oxide synthase expression was statistically significantly correlated with the expression of the VEGF receptor and the presence of macrophages and microglia. There was a negative correlation between oedema extension and the presence of NOS III and VEGF-R. The results seem to indicate a specific oedema modulating role of NO in cerebral metastasis.

Adolescent↗
PubMedDate not supplied

Expression of focal adhesion kinase (p125 FAK) and proline-rich tyrosine kinase 2 (PYK2/CAKb) in cerebral metastases, correlation with VEGF-R-, ecNOS III-labelling and morphometric data.

BACKGROUND: Cerebral metastasis occurs in about 20% of all neurosurgical patients. Cerebral metastases have a typical spherical morphology with a common central necrosis and perifocal oedema. It has been proposed that oedema extension, tumour volumes and infiltrative behaviour are partially mediated by vascular endothelial growth factor (VEGF) and nitric oxide (NO). In several systemic tumour entities NO is suggested as a factor which influences the metastatic potential. VEGF has recently been reported to influence the matrix related migratory activity by interaction with focal adhesion kinase (p125FAK) and proline-rich tyrosine kinase beta (PYK2/CAK beta). Nitric oxide, which is produced in metastases by three different NOS isozymes is capable of antagonizing the binding of FAK to matrix integrins. NO, VEGF and FAK/PYK 2 are therefore considered to be important mediators of the cerebral metastatic incidence, growth, infiltration and oedema extension. The aim of our present study was to investigate the expression of p125FAK and the coexpression with PYK2/CAK beta, VEGF-receptor FLT-1, NOS isozymes NOS I-III, capillary density and the histology in 130 specimens of resected cerebral metastatic tumours. A further analysis was performed to morphometrically evaluate tumour and oedema volumes and to correlate the immunohistochemical data in a subgroup of 40 patients. MATERIALS AND METHODS: Cryosections (N = 130) of metastatic resections were investigated immunohistologically using a 4-step scoring evaluation for the expression of NOS I-III, VEGF-receptor FLT-1, and capillary vessel presence by endothelial Von-Willebrand-Factor (VWF) staining. Tumour and oedema extension was measured in preoperative MRI (N = 40) scans by an image-processing device (Kontron) and the ratios of oedema volumes to total tumour volumes were calculated. The data were analysed statistically (Spearman rank order correlation and Kruskal-Wallis ANOVA) and correlated with the clinical data. RESULTS: FAK immunoexpression was observed in 50% of the specimens (31.2% gradings 2 and 3). We observed a significant coexpression (p = 0.0001) with PYK 2 labelling which occurred frequently in 74% of the specimens (42% gradings 2 and 3). The VEGF receptor FLT-1 could be detected in 70% of them, 24% at higher expression values 2 and 3. The expression of NO synthase was frequently observed. NOS I was detected in 83.6% of the specimens, values 2 and 3 in 40.5%. NOS III, the endothelial isoform, was observed in 39.4% of the specimens (gradings 2 and 3) and inducible NOS II in 29.4% (grading 2 and 3) of them. Coexpressions were statistically significant for FAK and NOS III (Spearman p = 0.008) and FAK and VEGF-R (p = 0.03). The morphometric evaluation resulted in tumour volumes between 2.0 and 83 cm3 (mean 22.5 +/- 19.1 SD) with oedema ratios between 0 and 100% (mean 62.2 +/- 22.5 SD). FAK expression correlated significantly (p = 0.06) with tumour volumes and histology. CONCLUSION: The frequent histotypic occurrence of FAK and PYK2 in metastases could be an important factor in the modulation of metastatic capacity and infiltrative behaviour and might influence the disease course. Judging from its frequent expression PYK2 may generate the more relevant signals. A further aspect is the possible interaction with endothelial NOS III and VEGF receptor, which could be important for the infiltrative behaviour in a latent hypoxic scenery and environment.

Brain Neoplasms↗