Intracerebral microdialysis of extracellular amino acids in the human epileptic focus.

Extracellular levels of aspartate (ASP), glutamate (GLU), serine (SER), asparagine (ASN), glycine (GLY), threonine (THR), arginine (ARG), alanine (ALA), taurine (TAU), tyrosine (TYR), phenylalanine (PHE), isoleucine (ILEU), and leucine (LEU) were monitored by using intracerebral microdialysis in seven patients with medically intractable epilepsy, undergoing epilepsy surgery. In association with focal seizures, dramatic increases of the extracellular ASP, GLU, GLY, and SER concentrations were observed. The other amino acids analyzed, including TAU, showed small changes. The results support the hypothesis that ASP, GLU, GLY, and possibly SER, play an important role in the mechanism of seizure activity and seizure-related brain damage in the human epileptic focus.

Paraganglioma of the cauda equina. A case report and review of the literature.

A 59-year-old man presented with clinical evidence of a primary tumor of the cauda equina region. It was well circumscribed and was completely removed by neurosurgery. Routine staining showed that it had structural similarities to an ependymoma, but immunohistochemistry with antisera to synaptophysin, NSE, chromogranin-A and PGP 9.5 proved it to be a neuroendocrine tumor, i.e. a paraganglioma. We propose the use of endocrine markers in cases with tumors of the cauda equina to differentiate a paraganglioma from an ependymoma. Paragangliomas appear to have a better clinical outcome than ependymomas. Recurrence after surgery for a paraganglioma in the cauda equina region, especially if it is encapsulated, is rarely encountered.

Dynamic study of supratentorial gliomas with L-methyl-11C-methionine and positron emission tomography.

The regional kinetics of intravenously injected L-methyl-11C-methionine (11C-L-methionine) in the brain was investigated by positron emission tomography (PET) in 14 patients with gliomas. In both tumor and unaffected brain the tracer uptake reached a nearly constant level in 5 min or less. The ratio between the uptake of 11C-L-methionine by high-grade tumors and the uptake by unaffected brain was 1.9-4.8. In two cases of low-grade astrocytoma the ratio was 0.8-1.0. High uptakes of 11C-L-methionine occurred in gliomas even in the absence of blood-brain barrier defects as observed by other methods. This indicates that besides active transport of amino acid, a larger extracellular space in tumor as compared with unaffected brain tissue may also contribute to the increased uptake of 11C-L-methionine--derived radioactivity. In some patients delineation of the tumors was improved by use of PET with 11C-L-methionine as compared with computed tomography, angiography, and, in some instances, PET with 68Ga-EDTA. PET with 11C-L-methionine permits better evaluation of the tumor extent and may affect preoperative grading.

Dental radiography after age 25 years, amalgam fillings and tumours of the central nervous system.

The aim of the study was to investigate the importance of diagnostic dental radiography and amalgam fillings as risk factors for tumours of the central nervous system (CNS). This population-based case-control study included subjects aged 25-74 years, living in the catchment area of the Neurosurgery Department of Uppsala University Hospital in Sweden. A total of 192 cases of glioma, 99 cases of meningioma and 42 cases of acoustic neurinoma were identified between 1987 and 1990. A control group of 343 subjects was matched on age, gender and parish. Information about dental exposure was obtained by a self-administered questionnaire and from dental records. For those who had a dental radiography at least once a year after age 25 years, a relative risk of 2.1 (95% confidence interval (CI) 1.0-4.3) was seen for meningioma, while for other subgroups of CNS tumours the relative risk was close to unity. No association was observed between the number of amalgam fillings and CNS tumours. In conclusion, there was no clear evidence that dental radiography or amalgam fillings is related to the development of tumours of the CNS.

[Clear connection between gun ownership and suicide. 92 per cent of attempts result in death]. / Klart samband vapeninnehav och självmord 92 procent avlider av skottskadan.

In a retrospective study involving 20 police districts in Sweden, 348 completed or attempted suicides with firearms were found to have occurred during the period, 1976-88. Statistics on civilian firearms ownership were obtained from police authorities. Firearm suicide was found to be significantly correlated to gun ownership, through the 25 per cent increase in gun ownership during the period was not accompanied by a corresponding increase in the overall suicide rate. The head was the primary target in suicide attempts, both with longarms (rifles and shotguns) and with handguns (pistols and revolvers). Handgun injuries were more common among the survivors. Only 4.6 per cent of the victims survived and could be discharged from hospital. Nearly 10 per cent of those using shotguns or rifles used a string, a rod or their toes to reach the trigger; all of them died. Apart from such well-known predisposing factors such as psychiatric disorders or alcohol abuse that were present in 43 per cent of cases, 24 per cent of the victims were found to have had somatic problems instead.

Prolapsed lumbar intervertebral disc with partial or total occlusion of the spinal canal. A study of 30 patients with and 28 patients without cauda equina symptoms.

The clinical findings and operation results in two series of patients with medial prolapse of an intervertebral disc with total or partial occlusion of the spinal canal are reported. In one of the series (30 patients) symptoms of cauda equina compression, with bladder and rectal disturbances, were present, and in the other series (28 patients) these symptoms were absent. The observation period was five years (median value). The late results are evaluated in relation to the time interval between the onset of symptoms and operation. In the series with caudal compression syndrome, sphincter disturbances persisted in 10 patients, six of whom underwent operation during the first week after the onset of symptoms. The prognosis was most favourale when the symptoms developed slowly. Seventeen patients have returned to work. The importance of early operation in patients with classical compression syndrome of the cauda equina is emphasized. In the series without caudal compression syndrome, the symptomatalogy varied. The duration of symptoms was strikingly long. Only 19 patients are able to work. The others are prevented from working by persistent backache and leg pains, and in four cases by pareses of the extremities. In these cases also the importance of early operation is stressed.

Glioma and occupational exposure in Sweden, a case-control study.

OBJECTIVES: The aim of the study was to analyse whether any job titles, industrial codes, and certain occupational exposures were associated with an increased risk of glioma. METHODS: A population based case-control study of incident primary brain tumours in adults was carried out in Uppsala, Sweden in the period 1987-90. The study included 192 cases of glioma and 192 matched controls. It also included cases with other tumours of the central nervous system with matched controls. Information from all 343 controls was used in this study. Information was collected by means of a questionnaire that was sent to all subjects. An occupational hygienist reviewed the questionnaires for self reported exposures to substances and assessed whether these reported exposures were plausible or not in the corresponding occupation. RESULTS: The kappa coefficient for those classified by the two methods ranged between 0.46 and 0.88, and they were almost the same for cases and controls. For men exposed to solvents a relative risk (RR) of 2.6 (95% CI 1.3 to 5.2) was found. For men exposed to pesticides the RR was 1.8 (95% CI 0.6 to 5.1), and for plastic materials the RR was 3.6 (95% CI 1.0 to 12.4). For men employed in forestry and logging the RR was 2.2 (95% CI 0.9 to 5.3) and in basic metal industries 2.0 (95% CI 1.0 to 4.0). CONCLUSION: An increased risk of glioma was associated with use of solvents, pesticides, and plastic materials but this should be interpreted with some caution.

Reliability of computed tomography in assessing histopathological features of malignant supratentorial gliomas.

A new method was developed whereby close comparisons can be made between components of a computed tomography (CT) image and neuropathological findings. This was achieved by a combination of intravital (terminal) CT, postmortem CT, and whole brain sectioning of formalin-fixed tissue. The method was applied in seven cases of malignant supratentorial astrocytic gliomas (Kernohan Grades III and IV) and in one case of thalamic ependymoma. The glioblastoma-like parts of the astrocytic gliomas were usually correctly delineated by postcontrast CT, although there were exceptions to this rule. Tumor components consisting of diffusely growing malignant astrocytoma were difficult or impossible to delineate by CT. Necrotic areas within the tumors were accurately outlined by postcontrast CT. Peritumoral edema was correctly delineated by CT, but growth of diffuse astrocytoma or the presence of astrocytic gliosis within this edematous area seems difficult or impossible to evaluate by current CT techniques.

Positron emission tomography and computed tomography in differential diagnosis between recurrent or residual glioma and treatment-induced brain lesions.

In previous studies of supratentorial gliomas with positron emission tomography (PET) and computed tomography (CT), high uptakes of L-methyl-11C-methionine (11C-L-methionine) were found even in astrocytomas without blood-brain barrier defects as judged by CT or 68Ga-EDTA PET. In a number of patients examined after radiation therapy, there were no consistent changes in the high uptake values. In the present investigation PET and CT were compared with regard to their abilities to visualize and delineate recurrent tumors and treatment-induced brain defects and to differentiate between them. The study was undertaken on four patients who were long-term survivors after treatment for high-grade gliomas. For PET, 11C-L-methionine and 68Ga-EDTA were used. In two patients recurrent/residual tumors appeared considerably larger with 11C-L-methionine PET than with CT or 68Ga-EDTA PET. In one patient, no signs of recurrence were seen with any of these three methods, and in a fourth patient, whose condition was clinically stable, the findings at PET with 11C-L-methionine were non-specific. In areas corresponding to the surgical parenchymal defects, the 11C-L-methionine uptake and, except in one case, the local blood volume was markedly reduced. PET with 11C-L-methionine thus has a potential for distinguishing between postoperative brain lesions and tumor recurrence with a higher accuracy than CT.

Occupational factors associated with astrocytomas: a case-control study.

The most malignant form of all brain tumors is the supratentorial astrocytoma. Little is known about its etiology, but exogenous factors have been blamed. In this case-control study, 78 astrocytoma patients have been compared with 197 clinical and 92 population controls. An extensive questionnaire was used to gather information about occupational and residential environment exposure. Inquiries concerning groups of or individual chemicals elicited low rates of affirmative response, with negligible differences between cases and controls. However, the questions "working at an airfield" and "living near a petrochemical plant" indicated elevated risks in comparison with both control groups; so too did "living near a municipal sewage treatment plant." These results focus attention on exposure to organic compounds and should be considered together with similar findings in current research. No other occupation, branch of industry, or vicinity questions showed differences between cases and controls, with the exception of "living in the neighborhood of a paper mill or a saw mill," which gave moderately increased relative risks. A separate report gives the results from the nonoccupational part of the study.

In vitro quantitative autoradiography of [3H]-L-deprenyl and [3H]-PK 11195 binding sites in human epileptic hippocampus.

Distribution of the enzyme monoamine oxidase B (MAO-B) and the peripheral benzodiazepine binding site (omega 3 site) was studied by quantitative autoradiography using [3H]L-deprenyl and [3H]PK 11195, two tentative glial markers, as ligands. Sclerotic hippocampus from seven patients who had had anterotemporal lobe resection because of intractable complex partial epilepsy were investigated and compared with postmortem hippocampus from three nonepileptic controls. A significantly higher degree of L-deprenyl and PK 11195 binding was observed in the epileptic cases. The increased binding of both ligands correlated to extent of neuronal loss, but only PK 11195 showed correlation to degree of gliosis. We concluded that both ligands could provide useful markers for quantitating the degree of gliosis in pathologic states such as epilepsy. They may be applicable in future in vivo studies with positron emission tomography (PET).

Nonoccupational risk indicators for astrocytomas in adults.

We performed a case-control study on astrocytomas to test previous hypotheses and to generate new ones. The study groups consisted of 78 cases, 197 clinical controls, and 92 population controls. Comparisons with both groups of controls showed an excess risk for persons who had lived in the vicinity of a farm. The risk for persons exposed to herbicides or insecticides was elevated, although less so compared with the population controls. Frequent intake of smoked food was associated with an excess risk compared with the population controls but not when compared with the clinical controls.

Occupational exposure to magnetic fields and brain tumours in central Sweden.

Occupations with exposure to magnetic fields were studied in a population-based case-control study of male glioma and meningioma in Central Sweden. The study included 84 cases of glioma, 20 cases of meningioma and 155 controls. Information about job titles was obtained by means of a questionnaire. Three different methods were used to classify exposure 1) 'electrical occupations', 2) assessment of magnetic fields by an electrical engineer, 3) job values based on magnetic field measurements at work sites for occupational groups. When analyses were based on 'electrical occupations' a relative risk (RR) of 1.0 (95% CI: 0.4-2.4) was seen for glioma and 1.8 (95% CI: 0.3-3.6) for meningioma. When analyses were based on measurements a relative risk of 1.9 (95% CI: 0.8-5.0) was seen for glioma and 1.6 (95% CI: 0.3-10.2) for those ever in an exposed job of an average mean value of > 0.4 microT. A larger number of individuals was classified as exposed, when exposure was based on measurements. Information was available regarding several potential confounders, but none of them seemed to be of any importance. Our conclusion is that the results based on magnetic field measurements give some support to the hypothesis that magnetic fields exposure may play a role in the development of brain tumours.