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G Fries

Publications and source records attributed to G Fries.

At least 37 records · Page 2Linked to original sources
PubMed1994

Enhanced interleukin-1 beta release and longevity of glioma-associated peripheral blood monocytes in vitro.

Interleukin-1 (IL-1) plays a controversial role in the immune response. Besides its activation of immune cells and juvenile central nervous system cells, monocyte-derived IL-1 may be able to stimulate the malignant transformation and proliferation of glial brain tumor cells expressing IL-1 receptors. The aim of this study was to determine the growth pattern and the IL-1 beta release of long-term cultured peripheral blood monocytes of glioma patients. At 6- to 7-day intervals, the vital monocytes, characterized by CD14 immunophenotyping, were counted. By the use of a specific IL-1 beta enzyme-linked immunosorbent assay, the IL-1 beta content of monocyte culture supernatants derived from 13 subjects with glioma and from 12 controls were compared at Days 7, 21, and 100 of culture. Cell clusters of monocytes derived from glioblastoma patients survived more than 250 days in culture, whereas control monocytes survived only up to 114 days. The IL-1 beta release of glioma-associated peripheral blood monocyte cultures was about 50 times higher as compared with control monocyte cultures. Dexamethasone treatment at the time of blood sampling and recurrences of the gliomas did not influence the increase in the IL-1 beta expression of glioma monocytes. It seemed that at least subsets of glioma-associated blood monocytes, although they had been removed from the circulation, remained activated for a long period of time. We conclude that increased IL-1 beta production of glioma-associated peripheral blood monocytes and their longevity in vitro may be features of aberrant immune cell subsets. In future studies, the exact phenotyping of monocyte subsets will be mandatory.

Adult↗
PubMed1993

[Improvement of the absorption of the active substance 2'-hydroxy-5'-methyllaurophenoxamine (FLM 5011) with prodrugs and preparations].

Methods to improve the absorption of problem drugs are presented for the strongly lipophilic, poorly water-soluble, potential lipoxygenase inhibitor FLM 5011 (1). The water-solubility is improved by using prodrugs or by solubilizing. The characterization of solubility has been characterized with an suitable in vitro model system. The bioavailability of 1 in rabbits after oral administration is markedly increased using 1-prodrugs studied. The good correlation between the ABC measured in vitro and the AUC estimated in vivo demonstrates that it is possible to predict the bioavailability at the rabbit of highly lipophilic drugs such as 1 using the flow through model system.

Animals↗
PubMed1992

Neuroendoscopic technique for the operative treatment of septated syringomyelia.

The management of septated, chambered syringomyelia has until now been problematic because the usual operative methods cannot secure drainage of all chambers of the cavity. The development of a flexible neuroendoscope affords the possibility to perforate the septa under visual control which subdivide the cavity. We present our experiences with 11 cases of septated syringomyelia, which have been operated upon using a flexible neuroendoscope.

Endoscopes↗
PubMed1992

Suprasellar granular cell tumor.

A case of a suprasellar granular cell tumor, approximately 1.5 cm in diameter, in a 68-year-old woman is described. Diagnosis was established postoperatively by histopathological examination of the tumor tissue. The preoperative computed tomographic scan revealed a slightly hyperdense suprasellar mass with strong contrast enhancement. There was no evidence of calcification. The T1-weighted image on magnetic resonance imaging scan showed an isointense tumor with non-homogeneous enhancement after intravenous gadolinium diethylene-triamine-pentaacetic acid. In the proton-weighted image, the suprasellar mass presented a non-homogeneously enhanced signal. A non-homogeneous signal reduction was seen in the T2-weighted image.

Aged↗
PubMed1992

Occlusion of the pig superior sagittal sinus, bridging and cortical veins: multistep evolution of sinus-vein thrombosis.

Cerebral sinus-vein thrombosis may lead to severe hemodynamic changes, elevated intracranial pressure (ICP), and brain edema. It is supposed that progression of the thrombus from the sinus into bridging and cortical veins plays a key role in the development of these pathophysiological changes, but this hypothesis lacks experimental proof. The aim of this study, using a novel animal model of sinus-vein thrombosis, was to evaluate the effects of a standardized occlusion of the superior sagittal sinus and its bridging and cortical veins on hemodynamic alterations, on brain water content, and on ICP in domestic pigs. In 10 animals, the middle third of the superior sagittal sinus was occluded with a catheter-guided balloon. Five of these pigs received an additional injection of 1 ml fibrin glue into the superior sagittal sinus anterior to the inflated balloon, leading to an obstruction of bridging and cortical veins. In five control animals the balloon was inserted but not inflated. Five pigs underwent cerebral angiography. Four hours after occlusion, the brains were frozen in liquid nitrogen, and coronal slices were examined for Evans blue dye extravasation, regional water content, and histological changes. Occlusion of the superior sagittal sinus alone did not affect ICP or cerebral perfusion pressure (CPP). The additional injection of fibrin glue caused an obstruction of cortical and bridging veins as well as severe increases in mean (+/- standard deviation) ICP to 49.4 +/- 14.3 mm Hg, compared with 8.3 +/- 4.5 mm Hg in sham-treated controls and 7.1 +/- 3.9 mm Hg in animals with occlusion of the superior sagittal sinus alone. There was also a steep fall in the mean CPP to 34.2 +/- 19.6 mm Hg compared with 96.4 +/- 13.8 mm Hg in the control group. White-matter water content anterior to the occlusion site was elevated to 81.9 +/- 3.7 gm/100 gm frozen weight in the fibrin group as compared to 70.7 +/- 2.2 gm/100 gm in controls. Posterior to the occlusion site, water content did not differ among the three groups. Angiography demonstrated collateral flow via cortical and bridging veins in animals with occlusion of the superior sagittal sinus alone. Additional fibrin glue obstructed these collateral vessels. The data suggest a multistep process of pathophysiological alterations in patients with sinus-vein thrombosis and may explain why these patients present with a wide variety of symptoms: minor neurological deficits or headache might indicate thrombosis of the superior sagittal sinus and/or its bridging veins.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

Use of an in vitro absorption model system for predicting sustained release of verapamil.

It is shown that it is possible to characterize sustained release formulations in vitro using not only dissolution data but also an absorption model system. The mean dissolution time (MDT) has been shown to be a suitable parameter for evaluating sustained release formulations in vitro. t1/2 and mean residence time (MRT) have been shown to be convenient pharmacokinetic parameters for characterizing sustained release formulations. For comparing in vitro and in vivo results the quotients MDT normal/MDT retard and MRT normal/MRT retard do seem to be useful.

Adult↗
PubMed1991

Evaluation of collateral flow capacity in patients with vascular or tumorous lesions of the skull base by Doppler sonography.

In 12 patients with vascular or tumorous lesions of the skull base, the collateral flow capacity was examined by transcranial Doppler sonography and carotid compression studies. In four patients no cross flow mechanism was found, in two patients the test remained unclear, and in six patients the examination suggested a good collateral flow capacity. However, for this application of Doppler sonography no borderlines have yet been defined and thus interpretation is difficult. Intraoperative Doppler sonography was used in five patients and proved to be helpful for localisation of the internal carotid artery within skull base tumors.

Adult↗
PubMed1990

Brain oedema and intracranial pressure in superior sagittal sinus balloon occlusion. An experimental study in pigs.

About 2/3 of all patients with thrombosis of the superior sagittal sinus (SSS) develop signs of increased ICP and/or brain oedema (BE). The time of onset and the spectrum of symptoms in SSS thrombosis vary extremely. This variability might be caused by differences in pathomechanism like BE and rise of ICP, parameters studied in the present contribution. 10 domestic pigs received a standardized occlusion of the SSS with two different balloon types (spherical and cylindrical). They were monitored for several systemic and intracranial pressures. After 4 hours of occlusion the brains were examined for BE (Evans blue, water content). They were compared with those of 4 sham-operated control animals. 4 animals underwent cerebral angiography. Within 4 hours ICP rose to 60 mm Hg in the group with the spherical balloon. Normal ICP of 5-10 mm Hg was seen in the group with the cylindrical balloon and in the sham-operated controls. The water content of the white matter was elevated in both occlusion groups differing significantly from the control group. Haemorrhagic infarction of the frontal parts of the cerebrum occurred in animals with concomitant obliteration of bridging and cortical veins. We conclude from our experiments that SSS occlusion may initiate a multitude of possible pathomechanisms depending on the involvement of bridging veins, cortical veins and inner brain veins.

Animals↗
PubMed1988

Pathomechanism of brain oedema in experimental intracerebral mass haemorrhage.

The prognosis of intracerebral haemorrhage is extremely poor when arterial hypertension is present. We investigated elastance of the brain tissue and brain hydraulic conductivity in normotensive (MAP approximately 110 mmHg) and hypertensive (MAP approximately 170 mmHg/angiotensin infusion) cats following a stereotactically produced intracerebral haemorrhage. For 12 hours after the onset of haemorrhage we registered the course of ICP, subsequently the water content of cortex, white matter and basal ganglia as well as the interstitial concentration of serum proteins in the corresponding regions were determined (Evans-Blue, immunofluorescence). Hypertension was associated with a slight increase in ICP and tissue water content but with a 3 fold more elevated content of interstitial serum proteins. Immunofluorescence analysis showed the oedema in the hypertensive group to be vasogenic in nature and in the normotensive cats to originate from the haematoma itself. The generally poor outcome of intracerebral mass haemorrhage in hypertensive subjects could be ascribed to the nature of the concomitant brain oedema, as described in this study.

Animals↗
PubMed1988

Tissue elastance and fluid conduction in normotensive and hypertensive intracerebral mass haematomas.

This is an investigation into the prognostic factors of 117 patients with spontaneous normo- and hypertensive intracerebral haematomas, supported by animal experiments. Preserved tissue elastance and fluid conduction enables the drainage of intrinsic haematoma serum into the CSF spaces in normotensive patients, who showed an increased extension of a perifocal hypodensity in the CT. Arterial hypertension decreased the possibility of fluid resolution. Our experimental studies showed that in hypertensive cases the serum remained trapped in the haematoma, which explains the small hypodense area around the haematoma in most of the hypertensive cases. If as an exception in hypertensives of perifocal hypodensity develops then it acts as additional space-occupying factor. Corresponding observations were made in hypertensive animals which showed a reduced serum movement out of the haematoma, but an increased Evans-Blue content in the perifocal tissue. Both pathological mechanisms explain the poorer prognosis in patients with intracerebral haematomas associated with high arterial blood pressure.

Adult↗