Biomedical subjects
Publications and source records attributed to S Turtas.
Seven patients with redundant roots of the cauda equina were followed 2 1/2-10 years after surgical decompression. Improvement of signs and symptoms occurred in all patients. However, none of them was neurologically intact at the time of the last physical examination, although persistence of minimal neurological signs and/or occasional pain did not prevent a useful occupational activity.
Seventeen patients with minor cerebral contusion were selected from a series of patients with head injuries of various severity, who had undergone repeat evaluations of the regional cerebral blood flow. The mean global flow (expressed as mean global initial slope index) on early examination was found to be significantly lower, compared with that recorded in healthy volunteers. A tendency towards the recovery of higher flow values was apparent in repeat evaluations that were performed several weeks after the injury. Interhemispheric asymmetries of flow were a common occurrence, with lower perfusion and reduced attenuation values on computed tomography scans being, however, in good agreement only in approximately half of the cases.
The long-term results of operations to remove disc hernias were assessed clinically and electrophysiologically in two groups of patients treated by different surgical techniques. The electrophysiological parameters determined were the motor conduction speed of the sciatic nerve, the H reflex, the minimum latency of the F wave and quantitative analysis of the EMG by the Willison method. The preliminary results reported in the present paper are related to two comparable samples of patients who underwent hemilaminoarthrectomy or hemilaminectomy for disc hernia at L5-S1. They show that the incidence of after effects was lower in the patients treated by simple hemilaminectomy.
The third ventricle can be approached by performing a few surgical maneuvers: (a) dividing the ependyma on the inferolateral aspect of the choroid plexus of the lateral ventricle; (b) separating leptomeningeal bundles within the tela chorioidea, and (c) dividing the roof of the third ventricle along the stria medullaris. Main landmarks are the thalamostriate vein and the direct lateral vein. Small subependymal veins or neural branches of the posterior medical choroidal artery, or both, occasionally cross the access route. The third ventricle is seen through both the opening in the roof and the foramen of Monro. A wider exposure can be obtained by cutting the terminal segment of the thalamostriate vein.
The authors have critically reviewed 8 cases which have come under their observation of a lumbosciatic syndrome due to redundant nerve roots of the cauda equina. Some of the clinical and myeloradiculographic features appear to be characteristic of this rare syndrome. Surgical intervention by decompressing the nerve roots of the cauda equina offers a very favourable prognosis.
In vitro incorporation of 3H-leucine into proteins of subcellular fractions of brain tumors has been investigated. Protein-bound radioactivity of nuclei and soluble fraction significantly increased compared to values of the normal brain. Moreover, the study demonstrated that microsomes, the most active fraction in protein synthesis in the normal tissue, always showed lower values than neoplastic nuclei. The pattern of 3H-leucine subcellular uptake obtained in brain tumors might suggest some similarities to that seen in the early phases of brain maturation.
Transposition of lengthened omentum to the brain surface, transplantation of an omental graft, or superficial temporal artery--middle cerebral artery anastomosis were performed in dogs prior to transcranial occlusion of the ipsilateral middle cerebral artery at its origin, including the bifurcation of the internal carotid artery. Both omentum and by-pass were able to reduce the changes in cerebral blood flow, somatosensory evoked responses, cerebral water and electrolyte content, consequent to the ischaemic insult. In the experimental conditions adopted in this study, the effect of omental transposition in maintaining high levels of flow throughout the entire occluded hemisphere was more marked compared to that resulting from the other methods, while the onset of ischaemic cerebral oedema was affected approximately at the same degree by all procedures. The results point to the role of the transposed omentum in providing an effective collateral circulation to the ischaemic brain.
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A mobile neurinoma arising from a redundant nerve root of the cauda equina is reported. The abnormal length of the nerve root allowed the neoplasm to move in the cranio-caudal direction along two segments of the spine.
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Local cerebral ischaemia causes a significant decrease in norepinephrine, dopamine, 5-hydroxytryptamine in the cortical brain tissue of rabbits, associated with an increase in 5-hydroxyindoleacetic acid. Previous transposition of the omentum on to the brain surface maintains, to a large extent, physiological levels of these metabolites. This study stresses the role of the transposed omentum in reducing the effects of experimental occlusion of a major cerebral artery.
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Angiomas situated within the pontocerebellar cistern lie superficially on the ventrolateral aspect of the brain stem. Occasionally, minor extensions penetrate into the adjacent nervous structures. Five patients bearing such lesions were operated upon, using a microsurgical technique. Radical excision was performed in all cases. Within 2 to 12 months the patients had returned to their previous occupations, being fully able to work or attend school. There is increasing evidence for the effectiveness of surgical treatment of angiomas of the ventrolateral aspect of the brain stem and the cerebellopontine angle. The illness usually presents with hemorrhages of varying severity, ranging from mild to devastating. Impairment of consciousness, contralateral hemiparesis and ipsilateral cranial nerve palsies are the most frequent neurological signs after bleeding. The outcome following excision is primarily related to the preoperative condition. No additional deficits or only minor further impairment can be expected from surgical interference. Exploration is advisable whenever the malformation appears to lie on the surface rather than within the brain stem.
Two cases of reversible CT contrast-enhanced lesions simulating brain neoplasms are described. Following steroid therapy and shunting procedure normalization of the clinical signs and of the CT scans occurred. The role of a vasculomyelinopathy as a possible pathogenetic factor of these lesions is stressed.
Four cases of redundant nerve roots of the cauda equina are reported, and the pertinent literature is reviewed. This disorder mainly affects males. The clinical history ranges from months to decades. The illness often starts with low back pain or sciatica, or both. Motor and sensory impairment of the legs dominate the further course of the disease. Serpentine filling defects in the column of contrast are a characteristic (but inconstant) feature on myelograms. Abatement of signs and symptoms occurs following adequate decompression of the redundant roots.
Aminoacid incorporation into polyribosomes from the gerbil brain in a cellfree system is strongly affected by experimental ischaemia. Progression of the impairment of the protein synthesis in vitro occurs even following early reperfusion.
Occlusion of the middle cerebral artery severely affects the uptake of labelled leucine into various subcellular fractions from rabbit brain. Previous transposition of pedicled omentum to the cerebral surface maintains to a large extent the protein synthetic activity of the brain following arterial occlusion. The role of the transposed omentum in providing an effective collateral circulation and minimizing the occurrence of irreversible ischaemic lesions is stressed.
Occlusion of the middle cerebral artery induces a local decrease in percentage of tissue dry weight in rabbit brain, associated with flux of sodium and potassium in reciprocal directions. Cortical swelling occurs also in remote non-ischaemic areas. Previous transposition of the omentum majus to the brain minimizes the onset of oedema consequent on occlusion of a major cerebral artery. Increasing experimental evidence points to the role of omental transposition in providing an effective source of collateral circulation, thus strongly affecting the threshold for infarction.