Biomedical subjects
Publications and source records attributed to H Kourtopoulos.
Castration increases the central nervous system (CNS) sensitivity to hexobarbital as measured by an EEG-threshold method. Testosterone treatment in doses from 1 to 5 mg/kg/day decreases CNS-sensitivity and restores threshold values in castrated rats to a level found in normal young adult male rats.
The penetration and distribution of labeled benzylpenicillin and cefuroxime into normal and infected rat brain was studied. 15 rats were injected intravenously with radiolabeled antibiotic; 5 of these served as uninfected controls and 10 were previously infected by stereotactic deposition of 10(11) B. fragilis in the right frontal lobe inducing bacterial cerebritis. The animals were killed after administration of antibiotic. The brains were immediately frozen and cut into 20/micron sections. Autoradiographic recordings showed that benzylpenicillin was mainly distributed in the cerebrospinal fluid and pial vessels but no activity was found in the deeper grey or white matter. In contrast, cefuroxime was found not only in the surrounding but also in the centre of the infected area. The autoradiographic technique provides a valuable method for studies of the distribution of antibiotics in the brain.
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A retrospective analysis of 162 consecutive cases with ruptured intracranial aneurysm treated during the years 1979-1981 is presented. Total mortality was 33%. Eighty-four patients were in Botterell grades I-II and 62 were operated with a direct attack on the aneurysm. Thirty-eight were operated early with a mortality of 5% compared with 13% for those operated late. There was no difference in morbidity between the two groups. Of the patients operated with clipping, 66% made a "complete recovery" and 21% were classified as independent. Signs of delayed ischaemia were recorded in 42% of patients operated early as compared with 25% in the late surgery group. The frequency of rebleedings in the total material was 15%. Hospitalization time was significantly reduced in the early operated group. The importance of analysing the total management mortality and morbidity for evaluation and comparison between early and delayed surgery is discussed.
Although the use of a temporary clip in intracranial aneurysm surgery has been proposed by several Neurosurgeons in the past, its use today is not generally accepted. Modern surgical techniques have contributed to safer exposure and direct attack on the aneurysm. However, aneurysm surgery continues to be a direct attack on the aneurysm. However, aneurysm surgery continues to be a challenge to the Surgeon and occasionally demands the use of a temporary clip. Eighteen cases operated on with the use of a temporary clip have been analysed. The occlusion time of the feeding vessel and location of the temporary clip have been related to the outcome. There was no relationship between occlusion time of the feeding vessel and outcome in this material, whereas location of the temporary clip seemed to be of importance for the outcome in cases with aneurysms located in the middle cerebral artery.
The surgical treatment of spontaneous intracerebral haemorrhage (SIH) is still a matter of controversy, although most Neurosurgeons agree that surgery is indicated in selected cases. The introduction of computer tomography (CT) permits a more accurate determination of the localization, size and expansion of an intracerebral haemorrhage. The aim of this study is to evaluate the results of surgical and conservative therapy in selected cases and to search for parameters that could help to predict the outcome and facilitate the decision between surgery and conservative therapy. Seventy-four patients treated following SIH during the years 1976-1980 were analyzed. The decision for surgical treatment was made on the basis of the patient's conditions and the findings in the CT scan. Thirty-nine patients with mainly medium-sized haemorrhages underwent surgery and 35 were conservatively treated. The mortality after three months was 5/39 (13%) in the surgical and 7/35 (20%) in the conservative group. The volume of haemorrhage was significantly larger in the patients who died and 9/10 patients with a haematoma volume above 80 ml died. Five of these 10 were operated and the other 5 not and surgery seemed to be of little benefit to this group. Dilatation of the contralateral ventricle is another indicator of a bad prognosis. Long-term follow-up investigation was carried out 4-38 months after the initial treatment. Total mortality was 19 out of 68 patients that could be reached for late follow-up. Eleven patients (29%) were fully recovered and 16 had minor neurological deficits. There was no difference in late results between the surgical and the conservative groups, but the patients in the surgical group were generally in a worse condition and had larger haemorrhages that the others. The fact that the total mortality in this material is lower than in other conservatively treated series favours surgery in selected cases of SIH. The use of CT gives valuable information as to the prognosis and especially the volume of haemorrhage seems to be a good prognostic factor.
The effect of a single intraperitoneal dose of ethanol (2 g/kg) given 30. min. prior to intravenous administration of benzylpenicillin (20, 40 and 80 mg/kg) was studied in rats. Ethanol pretreated animals showed lower blood and brain tissue levels of penicillin, 15 and 30 min. after the administration of the two lower penicillin doses. This difference was not observed when the penicillin dose was raised to 80 mg/kg. The quotient between brain and serum concentrations was increased 45 min. after the injection of 20 mg/kg of penicillin. Urine collection during the following 2 days showed an increased urine volume during the first 4-hour period in animals pretreated with ethanol. During the same time period they excreted less benzylpenicillin than the controls.
Morphine has been determined in serum, cerebrospinal fluid (c.s.f.) and in five brain regions in the rat after a single intravenous dose, using high performance liquid chromatography with an electrochemical detector. In pure solution 50 pg morphine and 200 pg naloxone could be detected. Maximal concentrations of morphine were observed in serum and in most brain regions 5 min after administration of morphine. There was a rapid decline in morphine concentrations during the first 30 min, in serum and in all brian regions studied. The morphine concentration in the c.s.f. was constant for the first 30 min, but 30 min later there was a dramatic increase, suggesting that elimination through the c.s.f. could be an important way of eliminating morphine in the central nervous system.
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Explore the source record for details and available documents.
The heads of neurosurgical patients were subject to 2 scrubbings with hexachlorophene detergent, performed in the ward prior to operation. After this single change of routines the frequency of wound infections after craniotomy dropped 4-fold, from 2% to 0.5%. The result indicates that the scalp of the patient is the major source of the staphylococci that cause neurosurgical infections.
A neurosurgical patient with postoperative meningitis caused by Serratia marcescens was treated with intraventricular as well as intramuscular gentamicin. Gentamicin concentration in serum and CSF was determined at different times after the administration. Serratia marcescens could not be isolated from CSF after 3 days of therapy. Determination of gentamicin concentrations in CSF showed that gentamicin should not be given intraventricularly more than once a day to avoid accumulation of the drug. No adverse effect was noticed although the CSF concentration reached 450 mug/ml.
A quantitative and qualitative study of the superior laryngeal nerve (SLN) and its branches was performed on the intact nerve and after experimental denervation procedures. The distribution patterns of the myelinated fibers of the intact internal (SLNI) and external (SLNE) branches in the rat were unimodal with a fiber diameter range of 0.5-12 microns and with peaks at 2-4 microns. Numerous unmyelinated fibers, ranging in diameter from 0.1-2.3 microns, were evenly distributed all over the nerve. The SLNI contained no degenerated myelinated fibers after intracranial vagotomy, but about 25% of the unmyelinated fibers showed degenerative features. In the SLNE 2-10% of the myelinated fibers and about 25% of the unmyelinated fibers were degenerated after the same procedure. Extracranial vagotomy caused degeneration of nearly all fibers in the SLNI and SLNE. Single unmyelinated fibers appeared normal after this procedure. Occasional myelinated and a few unmyelinated fibers were degenerated after excision of the superior cervical ganglion. It is inferred from the results that a majority of the myelinated fibers in the SLN (96-99%) are sensory, with the cell bodies in the extracranial vagal ganglia. The SLNE was also found to be predominantly sensory, as only 2-10% of the myelinated fibers and about 25% of the unmyelinated fibers had their cell bodies in the brainstem. Single myelinated and a few unmyelinated fibers in both the SLNI and SLNE had their origin in the superior cervical ganglion.