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Biomedical subjects

E Grote

Publications and source records attributed to E Grote.

At least 37 records · Page 2Linked to original sources
PubMed1992

Periventricular neurocytoma: a pathological entity.

Three cases of periventricular neurocytomas are presented. All patients had a large but well-circumscribed, hyperdense tumor with insignificant contrast enhancement in the lateral and third ventricle, causing hydrocephalus. Calcification was present in one patient. Angiography revealed a blush tumor enhancement in two cases. Surgical removal was complete in two patients and incomplete in one. Light microscopy showed a cell pattern that resembled either ependymoma or oligodendroglioma. However, in all cases the tumor was confirmed to be a neurocytoma by immunocytochemical analysis that showed reactivity for synaptophysin and/or neuron-specific enolase in a high percentage of neoplastic cells. With respect to the literature it is concluded that neurocytomas represent an individual pathological entity of supratentorial midline tumors. Complete surgical removal without irradiation is the recommended treatment.

Adult↗
PubMed1991

Animal experiments with a new dura graft (polytetrafluorethylene)--results.

A comparative animal experiment study on rabbits was performed to test a synthetic dura (expanded polytetrafluorethylene = ePTFE = Gore-Tex Surgical Membrane). For the purpose of comparison with the ePTFE implanted in the left hemisphere, lyophilized natural dura (Lyodura) was used and removed from the subjects after two, eight and twelve weeks. There were no rejection reactions. The lyophilized dura showed pronounced environmental reaction, with cellular permeation and indications of revitalization. The ePTFE manifested only slight reaction and remained inert in an enclosing sheath of connective tissue. The biocompatibility and other properties, such as simple handling and resteriliziability, of ePTFE can thus be assessed as positive.

Animals↗
PubMed1990

Biogenesis of synaptic vesicle-like structures in a pheochromocytoma cell line PC-12.

The presence of unique proteins in synaptic vesicles of neurons suggests selective targeting during vesicle formation. Endocrine, but not other cells, also express synaptic vesicle membrane proteins and target them selectively to small intracellular vesicles. We show that the rat pheochromocytoma cell line, PC12, has a population of small vesicles with sedimentation and density properties very similar to those of rat brain synaptic vesicles. When synaptophysin is expressed in nonneuronal cells, it is found in intracellular organelles that are not the size of synaptic vesicles. The major protein in the small vesicles isolated from PC12 cells is found to be synaptophysin, which is also the major protein in rat brain vesicles. At least two of the minor proteins in the small vesicles are also known synaptic vesicle membrane proteins. Synaptic vesicle-like structures in PC12 cells can be shown to take up an exogenous bulk phase marker, HRP. Their proteins, including synaptophysin, are labeled if the cells are surface labeled and subsequently warmed. Although the PC12 vesicles can arise by endocytosis, they seem to exclude the receptor-mediated endocytosis marker, transferrin. We conclude that PC12 cells contain synaptic vesicle-like structures that resemble authentic synaptic vesicles in physical properties, protein composition and endocytotic origin.

Animals↗
PubMed1989

Intracerebral malignant fibrous histiocytoma at site of a previously excised low grade glioma.

The case of a 42-year-old patient is reported who developed an intracerebral malignant fibrous histiocytoma at the site of an oligoastrocytic mixed glioma which had been excised 2 1/2 years previously. Reasons for the extreme rarity of intracranial malignant fibrous histiocytomas, the probability of a traumatic aetiology of this particular tumour, and the possible significance of intratumoural cells positive for glial fibrillary acidic protein (GFAP) are discussed.

Adult↗
PubMed1988

False-negative brainstem auditory evoked potential recordings in a case of multiple acoustic neuroma.

A case history is reported to demonstrate that electrophysiological testing (brainstem auditory evoked potentials, BAEP and stapedius reflex) may fail in the search for cerebello-pontine angle tumours. The clinical history began with repeated episodes indicating a disorder of the vestibular system. Repeated testing of BAEP exhibited normal curves before and after surgery on the right side. This case serves as a reminder that normal BAEP do not necessarily exclude the presence of an acoustic neuroma developing in the immediate vicinity of the vestibular nerve.

Brain Stem↗
PubMed1988

The critical first minutes after subarachnoid hemorrhage.

Six patients were observed during recurrent subarachnoid hemorrhage (SAH). Three each had an open skull and intact dura mater and demonstrated an extreme increase in intracranial pressure (ICP) that developed within 1 minute and then declined over several minutes. Three other patients were investigated with transcranial Doppler sonography before, during, and after recurrent bleeding, and their hemodynamics were studied. There is conclusive evidence that acute spontaneous SAH is often followed by an intracranial circulatory arrest lasting for several minutes and caused by a peak of ICP in the range of mean arterial levels. The mechanisms involved are discussed. There are strong indications that this temporary intracranial circulatory arrest promotes hemostasis, but may constitute a severe ischemic event.

Female↗
PubMed1985

Giant pituitary adenomas.

Out of a series of 515 pituitary adenomas 77 giant tumours seen between 1953 and 1983 were selected and the current problems of their management discussed. Since CT became available the incidence of discovery of giant pituitary adenoma became higher at 20% against 11%, especially in elderly patients. The extent and the form of giant adenomas and the different types of expanding and invasive adenomas are described in detail. A large group--most invasive adenomas of younger aged patients comprises mostly giant prolactinomas. A second large group of expansive endocrine inactive group seems to be characteristic for older age groups. Previously reported extremely high mortality can be lowered thanks to microsurgery and in our experience also due to the use of CUSA and Laser. In this series mortality dropped from 30% to 10%, and even to 6% in the last five years. However the morbidity rate, even if transient, remained high. Operative approaches, according to site and extent are discussed. The preoperative therapy with Dopamine-agonists in form of depot-injection, may open up a new possibility of lowering the operative risk in giant prolactinomas, by reducing the tumour size and signs.

Adenoma↗
PubMed1983

The fibrinolytic activity of cerebrospinal fluid after subarachnoid hemorrhage.

Fibrinolytic activity of cerebrospinal fluid and peripheral blood was studied in 14 patients with subarachnoid hemorrhage during the high-risk period of subarachnoid rebleeding. Fibrinolytic activity of cerebrospinal fluid or peripheral blood could not be demonstrated. Determination of fibrin degradation products showed high levels in cerebrospinal fluid, being a result of meningeal irritation. The findings in this study--as well as other observations--suggest, that antifibrinolytic therapy should not be administered in patients with subarachnoid hemorrhage.

Antifibrinolytic Agents↗
PubMed1982

Recurrent cerebral embolization from a carotid bifurcation aneurysm.

In addition to heart disease and ulcers of the carotid artery, partially thrombosed large or giant aneurysms of the carotid territory may be the source of emboli into the middle cerebral distribution. Recurrent ischaemic attacks, characteristic of embolization, ceased after clipping of a sclerotic carotid bifurcation aneurysm that had never bled. Relevant literature is reviewed.

Carotid Arteries↗
PubMed1982

Characteristics of giant pituitary adenomas.

An analysis of 21 giant pituitary adenomas is presented. Giant pituitary adenomas with a diameter of more than four cm mostly perforate dura and diaphragm, invade the cavernous sinus, and spread extradurally into anterior and middle cranial fossae or into the frontal or temporal lobes. Endocrinologically, a third are prolactinomas, and a half are non-secreting tumours leading to pituitary failure. Clinical, radiological, and operative characteristics lead to the conclusions that multishaped dura-penetrating extension is not due to locally destructive growth, but is the result of late diagnosis. Because radical cure by operation and radiotherapy is hardly likely, early operative treatment is necessary even when an excellent endocrinological response to medical therapy is present.

Adenoma, Chromophobe↗
PubMed1981

Formation and Location of 1,4-beta-Glucanases and 1,4-beta-Glucosidases from Penicillium janthinellum.

Formation and location of 1,4-beta-glucanases and 1,4-beta-glucosidases were studied in cultures of Penicillium janthinellum grown on Avicel, sodium carboxymethyl cellulose, cellobiose, glucose, mannose, and maltose. Endo-1,4-beta-glucanases were found to be cell free, and their formation was induced by cellobiose. 1,4-beta-Glucosidases, on the other hand, were formed constitutively and were primarily cell free, but with a small amount strongly associated with the cell wall. Low 1,4-beta-glucosidase activities of periplasmic or intracellular origin were also found. A rotational viscosimetric method was developed to measure the total endo-1,4-beta-glucanase activity of the culture (broth and solids). By this method, it was possible to determine the endo-1,4-beta-glucanase activity not only in the supernatant of the culture but also on the surface of the mycelium or absorbed on residual Avicel. During a 70-liter batch cultivation of P. janthinellum, the adsorption of endo-1,4-beta-glucanases by residual and newly added 10% Avicel was measured. The adsorption of soluble protein and endo-1,4-beta-glucanases by Avicel was found to be largely independent of the pH value but dependent on temperature.

Journal Article↗
PubMed1980

Clinical and Endocrinological findings in ectopic pinealoma and spongioblastoma of the hypothalamus.

Cystic spongioblastoma and ectopic pinealoma occurring simultaneously were found in a 16-year-old male patient, and produced destruction of the hypothalamus. The clinical course extended for over four years. The clinical picture was characterized by a defect of osmo- and thermoregulation and by defective function of diencephalic nuclei and the sympathetic nervous system. The releasing factors for ACTH, TSH, LH, and FSH were lacking and produced corresponding disturbances of pituitary function. Because of the lack of hypothalamic inhibiting factors the prolactin level was increased, and the HGH level was stimulated by arginine loading and inhibited in the glucose test. The intact neurones in the ventromedial nucleus of the hypothalamus could be seen on microscopical examination. Clinical and endrocrinological findings were more suggestive of the diagnosis than the radiological ones. Computerized tomography showed multiple "tumour" localizations without any displacement signs. The occurrence of ectopic pinealoma and spongioblastoma in the same case would suggest, from the pathological point of view, a common dysontogenetic origin developing from the local elements of the nervous tissue.

Adolescent↗