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O Gratzl

Publications and source records attributed to O Gratzl.

At least 73 records · Page 4Linked to original sources
PubMed1993

Long-term survival of autologous adrenal medulla grafts in the great omentum of the rat.

The omentum, a rich source for trophic and angiogenic factors, was explored as a potential intermediate transplant site to facilitate long-term survival of chromaffin tissue. Autologous rat adrenal medullas were grafted into omental pockets. All grafts became densely vascularized. The grafted chromaffin tissue exhibited strong immunoreactivities for tyrosine hydroxylase, synaptophysin and chromogranin A throughout the observation period of 16 weeks. The expression of these markers implies that grafted chromaffin cells retained the key enzyme for catecholamine biosynthesis and the organelles required for catecholamine secretion. Moreover, intermediate transplant of chromaffin tissue to the omentum could provide a favourable conditioning microenvironment thus augmenting the potential for survival of functional chromaffin tissue.

Adrenal Medulla↗
PubMed1993

Penetration of rifampicin into the brain tissue and cerebral extracellular space of rats.

Rifampicin is used to treat neurosurgical shunt infections because of its excellent in-vitro activity against staphylococci and its adequate penetration into the CSF. However, nothing is known about rifampicin concentrations in the cerebral extra-cellular space (CES). We measured the penetration of rifampicin into the CES of anaesthetized rats by microdialysis using low-flow and equilibrium methods. Depending on the method, rifampicin concentrations in the CES were 0.3-1% of the serum concentration or 3-8% of brain tissue concentration, respectively. These experimental data in animals suggest that the recommended dose of rifampicin in man might be inadequate for treatment of some brain infections.

Animals↗
PubMed1993

Sonic stereometry in microsurgical procedures for deep-seated brain tumors and vascular malformations.

A frameless computerized navigating system was successfully employed in 20 cases of open microsurgical operations on deep-seated brain tumors and vascular malformations. Localization in space was made by measuring the traveling time of sonic waves (24 kHz) in air. This allowed the construction of mechanically simple, lightweight freehand targeting instruments. The tips can be localized with a measuring accuracy of +/- 1 mm intracranially on the basis of computed tomographic scans. This thoroughly redesigned sonic stereometrical device is being optimized for everyday use; magnetic resonance imaging, digital substraction angiography, and other diagnostic modalities will be implemented. Some perspectives on "computer-aided (neuro)surgery" are discussed.

Adolescent↗
PubMed1993

On-line monitoring of cerebral pH by microdialysis.

An on-line pH meter that can be mounted in microdialysis systems is described. The pH monitoring system was tested in rat cortex before and after middle cerebral artery occlusion (focal ischemia model). After probe implantation, pH values in the dialysate quickly reached a stable level that depended on perfusion medium (6.72, Ringer; 6.47, 0.9% saline) and flow rate (2 microliters/min). During ischemia, pH values sank rapidly and significantly, whereas lactic and ascorbic acid levels in the dialysate increased 9- to 12-fold. The pH of the dialysate is lower than that of the extracellular fluid because the relative recovery of carbon dioxide is about twice that of bicarbonate at the flow rate used, as shown in in vitro experiments. The pH meter would provide useful additional information during monitoring for ischemia, not only in experimental situations but also during neurosurgical intensive care. In the latter case, the on-line pH value would be a bedside parameter enabling fast feedback for setting analytical priorities and making therapeutical decisions.

Acid-Base Equilibrium↗
PubMed1993

T-cell receptor V-gene usage in neoplasms of the central nervous system. A comparative analysis in cultured tumor infiltrating and peripheral blood T cells.

The use of tumor-infiltrating lymphocytes in the treatment of central nervous system (CNS) neoplasms has met with serious obstacles due to difficulty of culture and poor characterization. Since in other tumors the therapeutic effects of tumor-infiltrating lymphocytes have been shown to rely on T-cell receptor engagement, the authors addressed the question as to whether expression of T-cell receptor variable (V) domains in cultured tumor-infiltrating lymphocytes from CNS is different from that of autologous cultured peripheral blood mononuclear cells. Infiltrating lymphocytes from CNS neoplasms, including primary malignancies, metastatic cancers, and meningiomas, were cultured in the presence of interleukin-2 and anti-CD3 monoclonal antibodies (MoAb's) in order to obtain optimum growth of T cells. Autologous peripheral blood mononuclear cells from the same patients were similarly cultured. After 4 to 5 weeks of culture, 97.3% +/- 2.6% (mean +/- standard deviation) of the resulting cell populations were CD3-positive lymphocytes. The expression of T-cell receptor V domains was then studied by using a panel of 12 MoAb recognizing gene products from T-cell receptor V-alpha 2, V-beta 5, 6, 8, and 12, V-gamma 4 and 9 families, and from two subfamilies of V-delta 2. Remarkably, in over 70% of all paired measurements, percentages of T cells expressing discrete T-cell receptor V-gene products were found to be virtually identical in tumor- and peripheral blood-derived cultured cell populations, with differences never exceeding 1%. In contrast, a different expression of individual V-gene products, concerning both alpha/beta and gamma/delta T-cell receptors, could be detected between cultured tumor-infiltrating lymphocytes and autologous peripheral blood-derived T lymphocytes in seven of 12 patients. In two cases, significant differences between the two populations were also observed in the proliferative responses obtained upon stimulation with staphylococcal enterotoxins that trigger defined V-beta T-cell receptors. Altogether, these data suggest that the T-cell receptor repertoire of cultured tumor-infiltrating lymphocytes from CNS tumors, suitable for use in adoptive immunotherapies, differs from that of autologous cultured peripheral blood mononuclear cells.

Adult↗
PubMed1992

Significant lateralisation of supratentorial ICP after blunt head trauma.

After blunt head trauma simultaneous left and right hemispheric intracranial pressure (ICP) monitoring revealed a pressure gradient of about 30 mmHg persisting until the 5th day after the accident equilibrating thereafter. ICP was elevated over the radiologically more compressed hemisphere. The supratentorial space seems to allow considerable interhemispheric pressure gradients. As a consequence epidural ICP monitoring should be performed over the hemisphere with signs of greater compression.

Brain Edema↗
PubMed1992

Aspirin as a risk factor for hemorrhage in patients with head injuries.

The role of aspirin as a risk factor in the occurrence of intracranial bleeding following head injury was investigated. Chronic subdural hematoma appears to be a suitable model for the evaluation of risk factors in the development of hemorrhage. The most common risk factors found in our study were, apart from age, chronic alcohol abuse (28%), consumption of cumarin-derivates (21%), aspirin (13%), and heparin (5%). A patient undergoing aspirin treatment must be considered at risk of development of chronic subdural hematoma. Aspirin should not be prescribed to patients with post-traumatic headaches.

Adult↗
PubMed1992

The role of laminectomy in the combined treatment of metastatic spinal cord compression.

A retrospective analysis of clinical data concerning 140 patients with spinal cord compression is presented. Treatment consisted of a surgical decompressive laminectomy followed by radiation therapy in 127 cases. Primary radiation therapy supported by steroids was applied in only 26 cases. A dose of 30-40 Gy in 15-20 fractions was delivered to all patients. Treatment outcome was analyzed by comparing motor function (categories: no deficit, mild deficit ambulatory, paraparetic not ambulatory, paraplegic), sphincter function, and pain relief before and after treatment in both modalities. Following laminectomy and radiation therapy, 82% of paraparetic patients regained their ability to walk, sphincter function improved in 68%, pain relief was achieved in 88%. Following radiation therapy alone, 64% of paraparetic patients became ambulatory, 33% showed a normalization of sphincter function, and 72% became pain free. Our results indicate that laminectomy should play a major role in the treatment of patients with metastatic spinal cord compression. The decision as to the treatment of choice has to be made individually for each patient taking into consideration his general condition, life expectancy, and origin of the primary.

Adult↗
PubMed1992

Extracellular antioxidants and amino acids in the cortex of the rat: monitoring by microdialysis of early ischemic changes.

Extracellular concentrations of ascorbic acid, glutathione, cysteine, uric acid, tyrosine, and tryptophan were monitored using intracerebral microdialysis in the left frontoparietal cortex of spontaneous hypertensive rats before, and for 3 h after, either focal ischemia [left middle cerebral artery occlusion (MCAO)] or sham operation. The size of the ischemic area and the position of the microdialysis probe were checked using the enzyme histotopochemical acid phosphatase reaction. The probe was always located in the cortex inside the stained area. Ascorbic acid levels rose immediately after MCAO and remained at about 12-fold for 3 h. There was a transient release of glutathione during 1-1.5 h. Uric acid concentrations were also increased but the differences did not reach significance. The levels of the amino acids tyrosine and tryptophan increased steadily after MCAO. The increases in cysteine were variable but significant. In some experiments, the pH of the dialysate was measured online. The parameters ascorbic acid, glutathione, cysteine, and pH are suitable for the early detection of cortical ischemic events by microdialysis.

Animals↗
PubMed1992

Does on-scene resuscitation affect in-hospital "do not resuscitate" decisions and mortality in patients with severe head injuries?

To evaluate the effect of on-scene versus in-hospital resuscitation of patients with severe head injuries with regard to "do not resuscitate" (DNR) decisions and in-hospital mortality, 561 patients were prospectively studied. Patients were grouped according to whether resuscitation initially occurred at the scene of the injury (group 1), in a regional hospital before transfer (group 2), or after direct admission to our neurosurgical center (group 3). The DNR and mortality rates within the first 48 hours (13%, 10%, 10%, respectively) as well as for the entire stay in the surgical intensive care unit (SICU) were comparable for the three groups. It has been pointed out that efficient resuscitation at the scene of the injury may, instead of improving overall outcome, increase morbidity and mortality rates because more severely injured patients now reach the hospital alive. We conclude, however, that primary aggressive treatment at the scene of the injury did not increase DNR and in-hospital mortality rates within the 48-hour follow-up period, nor for the total stay in the SICU. Investigation of long-term outcome will be important to further establish the efficacy of this approach.

Adult↗
PubMed1992

Lipoma of the cauda equina selectively involving lower sacral roots. Case report.

A 44-year-old male patient suffering from sexual and voiding dysfunction did not exhibit any sensorimotor deficit except for a lax anal sphincter with loss of the bulbocavernosus reflex (BCR). The absence of both the electrically induced BCR and cortical evoked responses to stimulation of the dorsal penile nerve as well as partial denervation of the pelvic floor musculature suggested damage to the lower sacral roots. The site of the lesion as indicated by electrophysiological findings was confirmed by computerized tomography and magnetic resonance imaging. The operation revealed a lipoma involving a few cauda fibers which produced a distension in the region of the conus medullaris.

Adult↗
PubMed1991

[Severe craniocerebral injuries: northwestern Switzerland 1984-1989].

Data from 561 severely head-injured patients treated in a Surgical Intensive Care Unit between 1984 and 1989 are analyzed. Age and sex distribution of the patients was comparable to findings in other studies. More than half of the patients were injured in road accidents, accidents involving cars representing the greatest risk. In 90% of all patients, severe head injury was the primary diagnosis. 60% of the patients were intubated within 30 minutes at the scene of the accident, as opposed to 17% of patients intubated in the emergency room within the same time interval. Patients resuscitated at the scene of the accident and admitted directly by helicopter arrived at the emergency room on average one hour after the accident; for those transported directly by ambulance, without intubation prior to admission, the average time interval was half an hour. Since the time interval between accident and onset of resuscitation is crucial, this difference in transportation times is not considered to be of major importance. Half of the patients who died in the Surgical Intensive Care Unit died within the first 48 hours, usually from primary severe brain damage. In 50% of the 446 patients from the first 4 years of this study the recoveries ranged from good to complete and 28% died. Only 3 (less than 1%) out of 446 patients were alive in a vegetative state, and 8% severely handicapped one year after the accident. Aggressive primary treatment did not increase the number of patients surviving in a vegetative or severely handicapped state.

Adolescent↗
PubMed1991

MR-imaging of chronic spinal cord injury. Association with neurologic function.

Twenty-two para- and tetraplegic patients with chronic spinal cord injuries were examined with magnetic resonance imaging (MRI). The clinical course in the entire rehabilitation period was recorded and an attempt was made to associate the functional status of the patients with the morphologic findings on MRI. Small and large spinal cord cysts and syringomyelia, cord atrophy, and spinal stenosis were found. Additionally, in a number of patients regions of increased signal intensity within the cord, interpreted as myelomalacia, and obliteration of the intradural extramedullary space, interpreted as arachnopathy, were noted. The large number (13/22) of cystic lesions in our patients was unexpected. It was in contrast to the rate reported in autopsy studies of paraplegics which note only few cysts. Whereas a direct association of morphologic findings with neurologic symptoms and the clinical course was difficult, it was found that patients with large cysts and spinal cord atrophy generally showed no tendency to improve in spite of the measures taken during the rehabilitation period. It is difficult to decide whether the initial trauma with cord hemorrhage is limiting the chance of neurological improvement or if a sequence of events leading from hemorrhage to gliosis and cystic necrosis is the determining factor.

Adolescent↗
PubMed1991

[Microsurgical removal of deep vascular malformations using sonar-stereometry].

The advantages of a new, dynamic sonar technology in open stereotactic microsurgery are demonstrated by means of three surgical procedures for deep-seated vascular malformations that are not easy of access. With this method, targets can be aimed at without using rigid, obstructive pointing devices as in conventional stereotaxy. On the contrary, it is possible to take advantage of preformed anatomical spaces reaching the lesion most carefully by means of light-weight, free-hand on-target instruments. The spatial information, correlated with a CT data set, is displayed in real time with an accuracy of +/- 1 mm. Additional image data from MR and digital angiography can be used interactively.

Adult↗
PubMed1991

Diagnosis and surgery of cerebellopontine-angle tumors.

The present report is based on the analysis of clinical data collected from 80 patients with cerebellopontine-angle tumors. Special reference is made to the history of the patient, the neurootologic test battery, particularly to the sensitivity and specificity of audiological and vestibular diagnostic procedures. The postoperative findings are evaluated especially with respect to postoperative morbidity and the preservation of facial nerve and auditory functions.

Audiometry↗
PubMed1990

Differential expression of the neural cell adhesion molecule NCAM 140 in human pituitary tumors.

We have analyzed the expression of the intracellular marker protein neuron specific enolase (NSE), synaptophysin (SYN) and of the cell surface marker NCAM (neural cell adhesion molecule) in both normal hypophysis and in pituitary adenomas in order to explore their potential use as diagnostic tools. All adenomas (4 prolactinomas, 3 growth hormone (GH) producing adenomas and 4 inactive adenomas) showed SYN and NSE immunoreactivity on tissue sections and this was confirmed by immunoblots. NCAM 140 (an isoform of NCAM with molecular mass 140 kDa) was detected by immunoblotting in normal human adenohypophysis, in all GH adenomas, and in three out of four inactive adenomas, but not in prolactinomas. Using highly sensitive techniques, NCAM immunoreactivity was observed by electron microscopy in all adenomas. These data indicate that NCAM 140 is a constituent of the cell surface of endocrine cells in both normal human adenohypophysis and its tumors. Since prolactinomas express very low levels of NCAM 140 compared to other hypophyseal tumors its virtual absence could be used for differential diagnosis. A combined analysis of NCAM, SYN and NSE could be useful to characterize inactive adenomas which are not immunoreactive for pituitary hormones and which may contain no or only low levels of the alpha chain of the glycoprotein hormones.

Adenoma↗