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Biomedical subjects

J Meixensberger

Publications and source records attributed to J Meixensberger.

81 records · Page 5Linked to original sources
PubMed1991

Cerebral blood flow and cerebrovascular reserve 5 years after EC-IC bypass.

CBF-studies using the Xenon-133-inhalation technique were performed in 18 patients with a unilateral carotid artery occlusion, 5.4 years after a STA-MCA procedure. For comparison we used the CBF data of 29 patients with the same diseases who had had conservative treatment for a variable period of time. CBF was measured during rest and after the intravenous administration of 1 g acetazolamide. During rest we found a significant interhemispheric difference in both groups. After activation with acetazolamide this difference disappeared in the bypass group, but not in the conservatively treated patients. Our data show that the bypass procedure obviously affects the vascular reserve capacity in a positive way over a long period of time. One criteria for success of STA-MCA procedures might be the cerebral reserve capacity tested with CBF-studies under activation.

Acetazolamide↗
PubMed1990

Hemispheric CBF-alterations in the time course of focal and diffuse brain injury.

Hemispheric CBF-alterations were studied in the time course of focal and diffuse-brain injury in a series of 25 head injured patients. Repeated 133 Xe CBF measurements with a mobile 10 detector system were performed in order to evaluate hemispheric CBF and cerebral vasoreactivity after change of PaCO2. Focal brain injury influenced hemispheric CBF varying in the time course: A hyperperfusion could be found within the first seven days after injury in 55 percent, whereas a hypoperfusion could be detected during the whole examination period in 18 percent. In diffuse injury we never saw such CBF abnormalities. On the other hand hemispheric CO2-reactivity was disturbed in focal and diffuse lesions, whereas a correlation between altered CBF at rest and CO2-reactivity could be only detected in 40% in focal injury. This investigations demonstrates no significant general, however, a partial influence of morphological damage upon cerebral microcirculation.

Adolescent↗
PubMed1990

Eleven times recurrences of a parasagittal falxmeningioma. Case report.

Although meningiomas are of benign character and generally of encapsulated growth, recurrence is a known problem in treatment. The authors present the time course of a recurrent parasagittal meningioma of the falx, which recurred eleven times. Despite modern radiological diagnostic methods, which made early diagnosis of recurrent tumour possible, and the use of modern microsurgical techniques with radical tumour extirpation and followed by radiotherapy, the fatal course of benign tumour disease could not be stopped.

Adult↗
PubMed1990

Factors influencing meningioma recurrence rate.

The authors studied retrospectively 23 recurrent meningiomas of a total series of 277 intracranial meningiomas operated upon in the Department of Neurosurgery, University of Würzburg, between 1983 and 1989. All tumours were diagnosed by CT scan or MRI and operated upon using modern neurosurgical operation technology such as CUSA, Neodym-YAG-laser and if necessary operating microscope. Age, sex and tumour site could not be demonstrated as an influencing factor of tumour recurrence. Histological subtype and cellular criteria (mitoses, nuclear pleomorphism, focal necrosis) also were not predictive for tumour recurrence in the individual case. We found longer recurrence-free intervals after complete tumour removal (Simpson's grade I or II) than after subtotal tumour excision (Simpson's grade III or IV), but this tendency was not statistically significant. Obviously the analysed factors especially histomorphological criteria and surgical grading do not reflect the total biological behaviour of recurrent meningiomas. Further studies on growth kinetics and tumours metabolism may help to solve this problems.

Adult↗
PubMed1990

Maffucci's syndrome with bilateral cartilaginous tumors of the cerebellopontine angle.

Maffucci's syndrome is characterized by the combination of multiple enchondromas (Ollier's disease) and hemangiomatosis. These hemangiomas develop in the subcutaneous tissue and form red-blue tumors dispersed over the whole body. Intracranial involvement is rare, making a preoperative radiological diagnosis and differentiation from other tumors rather difficult. The radiological characteristics and successful removal of the intracranial part of a chondrosarcoma of the cerebellopontine angle in a case of Maffucci's syndrome are reported in this paper.

Adult↗
PubMed1987

Association of polyomaviruses JC, SV40, and BK with human brain tumors.

Human brain tumors of 11 different types were analyzed by Southern blot analysis for the presence of JCV, SV40, and BKV. In 21 tumor specimens examined with JCV- and SV40-specific probes no positive hybridizations were obtained. Analysis for BKV DNA, however, revealed the presence of BKV-specific sequences in 11 of 24 tumor specimens. No hybridization was found in DNA from CNS tissues from different areas of 29 individuals without CNS tumors. The BKV DNA sequences were associated with high molecular weight cellular DNA, suggesting a chromosomal location. These data provide evidence for the involvement of BKV in the development of human brain tumors.

BK Virus↗
PubMedDate not supplied

Progesterone receptors are detectable in tumor fragment spheroids of meningiomas in vitro.

Progesterone receptors (PgR) are hardly to be found in monolayer tissue culture of meningiomas although 60-70% of native tissue specimens are PgR positive. Thus we examined whether RgR might be detectable in fragment spheroids of meningiomas in vitro. 25 meningiomas of 17 women and 8 men were investigated as native tissue, monolayer cell culture (primary passage and passage 3) and as fragment spheroid culture after 1 and 3 weeks. 18/25 native tissue samples revealed the PgR. There was no prevalence of sex or histological subtypes discernible. PgR was preserved in cell clumps of the primary passage but was completely lost when cells grew as monolayers (primary passage and passage 3). 21 meningiomas formed spheroids in vitro. In 8 out of 15 native PgR positive tumors the fragment spheroids showed PgR on cryosections after 1 and 3 weeks of culture. We conclude that PgR are preserved in a considerable amount of tumor fragment spheroids of meningiomas in contrast to monolayer culture. Thus spheroids seem to be a suitable tool to investigate progesterone/anti-progesterone effects in meningiomas in vitro.

Culture Techniques↗
PubMedDate not supplied

Dynamics of the immune system response in cerebrospinal fluid and blood of SIVmac-infected rhesus monkeys.

Paired sera and CSF samples were collected from SIVmac-infected macaques. Animals infected with SIVmac251 maintained low gag and high env-specific antibody levels in plasma. Increasing env-specific antibody titers in CSF were associated in one animal with strong intrathecal synthesis. SIVmac239-infected monkeys revealed high antibody titers of gag and env-specificity, in one animal accompanied by weak intrathecal synthesis of virus-specific antibodies. In all animals, the CD4/CD8 ratio in CSF decreased faster compared to blood.

Animals↗