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Biomedical subjects

I Podreka

Publications and source records attributed to I Podreka.

At least 73 records · Page 4Linked to original sources
PubMed1988

Neurophysiological aspects of auditory hallucinations. 99mTc-(HMPAO)-SPECT investigations in patients with auditory hallucinations and normal controls--a preliminary report.

In a symptom-oriented study 17 patients suffering from chronic auditory hallucinations were investigated by means of 99mTc-HMPAO-SPECT and compared with healthy controls. The results confirm the relative frontal hypoactivity in junction with a relative hyperactivity in the basal ganglia and mesial limbic structures in both hemispheres found in a previous pilot study in auditorily hallucinating patients. Our results should fortify the symptom-oriented approach in psychiatric research.

Adult↗
PubMed1987

[Reversible opening of the blood-brain barrier in the chemotherapy of malignant gliomas].

The concept of a blood brain or blood tumour barrier blocking the passage of lipid insoluble cytoreductive drugs from blood into brain-tumor, leads to a protocol of intraarterial injection of high dose methotrexate (MTX) during reversible, osmotic blood brain barrier disruption (BBBD). Malignant Gliomas of grades III and IV in 9 patients and one primary CNS-lymphoma in one patient have been treated in 2 to 5 sessions per patient with BBBD plus polychemotherapy (MTX, cyclophosphamide, procarbazine). Median progression free intervals (PFI) which are still in continuation are 12.2 months. Median PFI which had been terminated by tumour recurrence are 7.75 months.

Antineoplastic Agents↗
PubMed1987

Patterns of regional cerebral blood flow related to memorizing of high and low imagery words--an emission computer tomography study.

Patterns of regional cerebral blood flow were investigated in healthy volunteers who were either resting or memorizing meaningless words, abstract nouns, or concrete nouns, the latter being given either with or without an instruction to use visual imagery. Relative regional count rates were subjected to smallest space analysis (SAA) to study the structure of covariations. Memorizing of concrete nouns gave rise to the formation of a continuous correlational subspace which comprised inferior temporal and occipital regions. When concrete nouns were memorized without an imagery instruction the mean hemispheric count rate was higher on the right side, whereas the intentional use of imagery gave rise to a left preponderance. Analysis of correlational structures, however, suggests that in both cases the left hemisphere was predominantly engaged in task solution, and that the difference in hemispheric asymmetries is to be attributed to different modes of interhemispheric collaboration.

Adult↗
PubMed1987

Initial experience with technetium-99m HM-PAO brain SPECT.

Technetium-99m hexamethylpropyleneamineoxime ([99mTc]HM-PAO) brain single photon emission computed tomography (SPECT) was performed with a dual head rotating scintillation camera. Normal tracer distribution and side/side differences of counting rates were obtained in 11 healthy volunteers. Almost stable gray/white matter ratios were found (1.97-2.1) in one normal subject during 2 hr after tracer administration. Eighty-three investigated patients had the following diagnoses (in parentheses is percent of positive findings in each group): cerebral vascular disease 18 (94.4%), epilepsy 23 (82.6%), extrapyramidal disorders 8 (100%), dementia 12 (100%), headache 11 (63.6%), psychiatric disorders 11 (27.3%). In addition, SPECT was performed in 28 male volunteers during motor or visual imagery tasks and a significant increase (p = 0.035) of relative tracer deposition was observed in the left inferior occipital region during visual imagery when compared with motor imagery. The results indicate that [99mTc]HM-PAO SPECT is valuable for demonstrating pathologic and physiologic changes of the brain.

Adult↗
PubMed1986

Blood brain barrier modification and chemotherapy. Interventional neuroradiology in the treatment of malignant gliomas.

Postoperative interventional neuroradiology was performed in patients with malignant gliomas to increase target efficacy of chemotherapy. In 8 glioma patients the blood brain or blood tumor barrier was reversibly opened by intraarterial injection of hyperosmolar fluid (Mannitol 25%). One additional patient had primary lymphoma of the central nervous system. During barrier modification chemotherapeutic agents were applied intraarterially and intravenously. A total of 22 blood brain barrier modification procedures have been carried out until now, ranging from one to five per patient. A presently continuing tumor regression or tumor progression free intervals have been noted in 5 patients. Therapeutic effects are being evaluated from repeated computed tomography and single photon emission computed tomography examinations.

Adult↗
PubMed1984

[Noninvasive measurement of cerebrovascular circulation with the scintillation camera. A neurologic nuclear medicine study].

Repeated CBF-measurements can be performed after inhalation or intravenous injection of 133Xe. After the development of a bicompartmental model by Obrist et al. in 1975 atraumatic CBF-measurements became widely used but there were still some difficulties concerning the sensitivity of different flow-indices towards CBF changes in normals under test conditions or ischemia in stroke patients. Due to the "slippage phenomenon" mostly noncompartmental flow-indices are used for the detection of ischemic brain areas. In this study a scintillation camera, that is usually available in every nuclear medicine department, was used for atraumatic CBF-studies. A collimator consisting of hexagonal lead tubes (septa 0.2 mm thick; FWHM 1.7 cm in 10 cm) was constructed for this purpose. The obtained counting rate varied between 2432 and 9081 cps over the whole hemisphere and 116-1094 cps in regions of approximately 2.5 X 2.5 cm. In 31 patients with CVD CBF was measured with the intracarotid (i.c.) technique and 1 hour later after i.v. 133Xe-injection. Intravenous flow values were comparable to those obtained after i.c. 133Xe injection (fB X MFr = 0.904; p less than 0.001). In 12 of the used 13 regions also significant correlation coefficients were found. In order to estimate the reproducibility of the intravenous injection method CBF-measurements were performed in both hemispheres of 10 patients on two consecutive days. Highly significant correlation coefficients were found for hemispheric blood flow (r = 0.933; p less than 0.001) and temporal, frontotemporal, temporoparietal and praecentral regions, while in the high parietal, frontal and occipital region lower reporducibility was found. Normal CBF-values were obtained from 12 healthy volunteers (MF right hemisphere: 50.7 +/- 4.6 ml/100 g/min; MF left hemisphere: 50.6 +/- 4.6 ml/100 g/min). MF did not show any hyperfrontality, while F1 and the ISI gave highest flow values in frontal regions. The clinical status of 76 patients suffering from cerebral ischemia (68 with flow disturbances in one hemisphere, 8 with vertebrobasilar insufficiency) was estimated by a semiquantitative scorescale at time of admission and after an observation period lasting from 6 to 35 months. In each case CBF was measured twice: once in the subacute stage after onset of symptoms and once after the observation period. The duration of neurologic symptoms (TIA, RIND, CS) was compared to the obtained flow values. A significant relationship was found between the duration of symptoms and impairment of CBF, thus showing the prognostic value of intravenous CBF measurements.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1981

[Diagnostic value of dynamic scintigraphy in cases of cerebrovascular disease (author's transl)].

Serial and sequential scintigraphy is amongst the most important noninvasive screening methods for the diagnosis of stenosing or obliterative processes in the carotid territory. In order to check the reliability of the method, the scintigraphic findings in 150 patients were compared with the results of cerebral panarteriography. In the proximal portion (in the neck) there was agreement in 78.7%. Some under-estimation and over-estimation was found in 9% and 8.3%. False positive scintigraphic results were obtained in 2.3%, false negative results in 1.7% of vessels. In the distal territory (carotid syphon/middle cerebral artery) there was agreement in 87.9%. Some over and under estimates occurred in 5.7% and 6.4% respectively. The commonest causes for false positive and false negative results are discussed.

Adolescent↗
PubMed1980

Diagnostic and pathomorphological aspects of glioma multiplicity.

A series of 11 patients with multiple glioma foci is reported with emphasis upon isotope brain scan, angiography, and CT findings; autopsy data is available in 8 cases. In many patients it was necessary to combine the results of several diagnostic techniques in order to demonstrate all the foci proven at autopsy. Thus, the desirability of combining diagnostic techniques in the investigation of glioma patients must be stressed. In spite of this approach, however, multiple metastases and the various types of multiple gliomas are often indistinguishable from each other by current diagnostic techniques.

Adult↗
PubMed1980

[Electrophysiological studies in vincristin-polyneuropathy (author's transl)].

21 Patients with malignant brain tumors were treated with vincristine (1,4 mg/m2) in the course of combination chemotherapie, given in 14 days series over 3 months up to 26 month. 18 patients developed clinical signs of a sensory and 4 patients of a sensomotoric polyneuropathy. Changes in nerve conduction velocity of the N. peronaeus and N. suralis and amplitude of the evoked muscle response (M. extensor digitorum brevis) and nerve action potential were studied in dependency of the total vincristine dosage. The following conclusions were drawn. 1. Clinical occurrence of vincristine polyneuropathy and decrease of nerve conduction velocity of peroneal and sural nerve and the amplitude of the muscle response and nerve action potential are dosage dependent. 2. Sensory fibres appear to be damaged earlier and more severe than motor fibers, but this difference was statistically not significant. 3. Nerve conduction velocity of peroneal and sural nerve is normal or slightly decreased in vincristine polyneuropathy, but the amplitude of the evoked response in extensor digitorum brevis muscle and of the nerve action potential of the suralis nerve are markedly diminished. This result indicates that vincristine polyneuropathy is of primary axonal orgin. 4. If vincristine dosage is reduced to half or vincristine is discontinued after a reduction of the potential amplitude in the extensor digitorum brevis muscle below 1 mV, severe, not reversible polyneuropathies may be avoided.

Action Potentials↗
PubMed1978

Assessment of pharmacological effects on cerebral blood flow.

The effect of various drugs on hemispheric and regional cerebral blood flow (CBF) was investigated in a total of 410 patients. While a few drugs (midodrin, proxazole, vincamine, hexobendine, extract of ginkgo biloba, dextran and ouabain) were able to improve hemispheric CBF, only ephedrine combined with xanthines decreased CBF. For vincamine the dependency of the effect on certain plasma levels was established. Only ouabain of the tested cardiac glycosides effected CBF; their similar hemodynamic actions suggest here an influence of ouabain on cerebral vessels. For the evaluation of drug effects on rCBF the detection of heterogeneous responses is important. Such responses may be quantified by regression analysis. While intracerebral steal effects were observed only under certain circumstances, inverse cerebral steal phenomena may be caused by diverging actions of several drugs. If treatment is aimed at improvement of cerebral hemodynamics, only drugs with a demonstrated effect, at least on perfusion of ischemic regions, should be employed.

Cerebrovascular Circulation↗
PubMed1977

Electrophysiological studies on the "stiff-man" syndrome.

In addition to anamnestic and clinical data electrophysiological and pharmacokinetic investigations may be necessary for the diagnosis of stiff man syndrome. Continuous activity of motor units with superimposed bursts during muscular spasms was found by electromyography in the two patients reported. Rigidity and continuous activity disappears during sleep, after i.v. application of Tubocurarine and Diazepam, during Thiopenal anesthesia and after neural block with Procaine. Dipropylacetate and Baclofen improved the condition but did not lead to complete relaxation. Biperidenlactat and Magnesiumlaevulinat have only a temporary effect on rigidity. Neostigmine, Phenytoine, Glycine, Dopa and 5-Hydroxy-Tryptophan had no effect. Passive shortening or stretching of the m. biceps brachii as well as touching the skin increased motor activity which spread to other segments and to the contralateral side. The H/M ratio was increased but the silent period was normal. A combination of Diazepam and Dipropylacetate or Clonazepam was therapeutically effective in the cases reported. A central genesis, of the pathogenetic mechanisms discussed, is the most probable in our cases.

Brain↗
PubMed1977

[Abnormal scintigrams in demyelinating diseases of the brain (author's transl)].

In 6 patients with acute or exacerbating demyelinating disease and in 2 cases suffering from adrenoleucodystrophy (Schilder's disease) brain scintigraphy revealed areas with increased isotope uptake. The pathological foci were verified by autopsy in 4 cases and by inspection in 1. These foci are difficult to distinguish from other localized brain diseases causing increased isotope uptake; in addition to the clinical course and to spinal fluid abnormalities reversibility of the scintigraphic lesions indicate demyelinating diseases. The typical pattern of symmetrical lesions within the white matter and the progression of abnormalities from the occipital to the frontal lobe speak in favor of Schilder's disease.

Adult↗
PubMed1977

[The effect of vincamine on cerebral blood flow as a function of application rate (author's transl)].

The effect of infusions of 14,15-dihydro-14beta-hydroxy-(3alpha, 16alpha)-eburamenine-14-carbonic acid methylester (vincamine; Vincopront) on cerebral blood flow (CBF) was investigated by the xenon clearance method. In 12 patients receiving 30 mg vincamine within 35--40 min no significant changes in hemispheric or regional CBF were observed. 14 patients received 40 mg vincamine within 35--40 min: in this group hemispheric CBF was significantly increased (p less than 0.01) when compared to the spontaneous changes observed in a control group. The increase was particularly prominent in poorly supplied brain regions. This effect was proved statistically by regression analysis. In a patient with astrocytoma the tumor-hyperperfusion was diminished by vincamine while the flow to the surrounding brain improved. The results indicate the dependency of the vincamine effect on the rate of application and thereby on the plasma concentration of the drug.

Adult↗