Dependency of blood flow velocity in the middle cerebral artery on end-tidal carbon dioxide partial pressure--a transcranial ultrasound Doppler study.

The end-tidal carbon dioxide partial pressure (PCO2) response curves for the flow velocity in the middle cerebral artery were studied in 31 normal subjects with transcranial Doppler techniques. An exponential curve with an exponent of 0.034 mm Hg-1 was found to be a good fit to the recorded data. By means of this relationship, recordings of flow velocity in cerebral arteries can be normalized to a standard value of PCO2. Physiological aspects of cerebrovascular reactivity to PCO2 and the clinical implications of the PCO2 response curve are discussed. The normal material provides a reference for assessing pathological responses.

Chronic subdural hematomas: to drain or not to drain?

A consecutive series of 21 adult patients with chronic subdural hematoma was studied in respect to postoperative resolution of subdural collections and clinical improvement after burr hole evacuation without subdural drainage. This series was compared to a previously studied series of patients with chronic subdural hematoma in whom postoperative closed system drainage had been installed. Using the identical protocol for treatment and postoperative follow-up, we obtained identical results with respect to time-related neurological improvement and persistence of subdural collections in the undrained and drained series, except that the steadily progressive clinical improvement during the early postoperative phase (24 hours) in all cases of the drained series was not universal in the undrained cases. Our study suggests that, to avoid the possibility of early postoperative clinical deterioration, burr hole craniostomy and closed system drainage is advisable. We think that subdural drainage is not necessary when the installation of the drainage system seems to be technically difficult, as it may be in cases with considerable perioperative cortical expansion.

Clinicopathological relations of cerebral cavernous angiomas: observations in eleven cases.

Eleven cases of cerebral cavernous angiomas (cavernomas) were observed within a period of 3 years. Two patients presented with cerebral hemorrhage, five with epilepsy, three each with a progressive focal neurological deficit, and one with papilledema. The unruptured lesions had a heterogeneous density on computed tomography with relatively little contrast enhancement. Two lesions contained major cysts. In one of these cases, the cyst measured 5.5 cm in diameter, had an enhancing membrane, and was surrounded by brain edema. Angiography did not show hypervascularity in any instance. During exploration and histological processing, special attention was paid to signs of previous silent hemorrhages and to the degree of encapsulation of the lesion. Iron deposits (signs of previous hemorrhages) were seen to varying degrees inside all cavernomas as well as in the surrounding gliotic cerebrum, and a causal relation between iron deposits and epileptic seizures seems likely. Encapsulation was minimal with the ruptured cavernomas and particularly prominent with the cystic lesions. The membrane of the giant cystic lesion with peripheral brain edema had a histological structure similar to that of the membranes of chronic subdural hematomas. It is suggested that continuous growth of cavernoma cysts is the result of recurrent hemorrhages from sinusoids of the malformation and from the neocapillary network of the cyst membranes.

Noninvasive transcranial Doppler ultrasound recording of flow velocity in basal cerebral arteries.

In this report the authors describe a noninvasive transcranial method of determining the flow velocities in the basal cerebral arteries. Placement of the probe of a range-gated ultrasound Doppler instrument in the temporal area just above the zygomatic arch allowed the velocities in the middle cerebral artery (MCA) to be determined from the Doppler signals. The flow velocities in the proximal anterior (ACA) and posterior (PCA) cerebral arteries were also recorded at steady state and during test compression of the common carotid arteries. An investigation of 50 healthy subjects by this transcranial Doppler method revealed that the velocity in the MCA, ACA, and PCA was 62 +/- 12, 51 +/0 12, and 44 +/- 11 cm/sec, respectively. This method is of particular value for the detection of vasospasm following subarachnoid hemorrhage and for evaluating the cerebral circulation in occlusive disease of the carotid and vertebral arteries.

Meningioma of the anterior part of the third ventricle. Case report.

The authors present a case of meningioma located in the anterior part of the third ventricle. The mass was successfully removed through a right-sided transventricular approach after stereotaxic biopsy. A review of the relevant literature is included.

The course of chronic subdural hematomas after burr-hole craniostomy and closed-system drainage.

A consecutive series of 32 adult patients with chronic subdural hematoma was studied in respect to postoperative cerebral reexpansion (reduction in diameter of the subdural space) after burr-hole craniostomy and closed-system drainage. Patients with high subdural pressure showed the most rapid brain expansion and clinical improvement during the first 2 days. Nevertheless, a computerized tomography (CT) scan performed on the 10th day after surgery demonstrated persisting subdural fluid in 78% of cases. After 40 days, the CT scan was normal in 27 of the 32 patients. There was no mortality and no significant morbidity. Our study suggests that well developed subdural neomembranes are the crucial factors for cerebral reexpansion, a phenomenon that takes at least 10 to 20 days. However, blood vessel dysfunction and impairment of cerebral blood flow may participate in delay of brain reexpansion. It may be argued that additional surgical procedures, such as repeated tapping of the subdural fluid, craniotomy, and membranectomy or even craniectomy, should not be evaluated earlier than 20 days after the initial surgical procedure unless the patient has deteriorated markedly.

Estrogen and progestin receptors in meningiomas: clinicopathological correlations.

Estradiol and progesterone receptors were studied in 44 patients with meningiomas and correlated to the clinicopathological features and amount of preoperative corticosteroid therapy. Thirty-four (77%) of the meningiomas contained high titers of specific high-affinity cytosol [3H]promegestone (R 5020) binding sites (mean 2,902 fmol/g tumor; range 0-9,598 fmol/g tumor) whereas only miniscule amounts of a nonspecific cytoplasmic [3H]estradiol binding component (mean 48 fmol/g tumor; range 0-201 fmol/g tumor) were detectable. No nuclear binding activity for [3H]estradiol was demonstrable. There was no convincing correlation between high PR activity and the age, sex, or menopausal status of the patients. The correlation study between the amount of preoperative corticosteroid therapy with the amount of [3H]promegestone binding revealed no dose relationship. Correlating [3H]promegestone content with the histologic type, we found 96% of meningothelial, 71% of transitional, and 40% of fibroplastic meningiomas to contain progesterone receptors. The necessity of in vitro studies is stressed to assess the biosynthesis and biological activity of the progesterone receptor in meningiomas, which is apparently not estrogen regulated, as is the case in other estrogen target tissues.

Biological expression of steroid hormone receptors in primary meningioma cells in monolayer culture.

Primary meningiomas have been grown in monolayer culture and tested for the presence of steroid hormone receptors and sensitivity to various steroids and steroid antagonists. None of the 10 solid tumors or the primary cultures derived from them contained estrogen receptors, either in the cytoplasm or in the nucleus. Progesterone receptors were present in 50-70% of the solid tumors and some of the primary cultures. Four of four and five of five primary cultures contained, respectively, androgen and glucocorticoid receptors. When one of the primary cultures was tested for growth sensitivity to estrogen, tamoxifen, progesterone, hydrocortisone, and dihydrotestosterone, the last two had noticeable stimulatory effects on growth by day 5. Interestingly, only androgen and glucocorticoid receptors were present in the primary tumor cells in culture, suggesting that these receptors mediated the effects of their respective hormones on growth.

Failure to demonstrate a vasoconstrictive effect of vasopressin on the internal carotid and middle cerebral arteries: a transcranial ultrasound Doppler study.

Vasopressin (AVP) was infused into four healthy human volunteers to explore by Doppler ultrasound the vasoconstrictive action of AVP on the internal carotid (ICA) and the medial cerebral artery (MCA, transcranial Doppler technique). Although AVP levels rose to 74.2 pg/ml (+/- 13 pg, SEM) no significant changes of flow velocity were observed in the ICA as well as the MCA. There was no effect on the pulsatility index of the MCA velocity profile indicating that peripheral vascular resistance remained unchanged during AVP infusion. These results do not support an effect of AVP at high physiological levels on the vascular diameters of the ICA, MCA and cerebral arteriolar system in humans.

Atlanto-axial fusion with transarticular screw fixation.

We reviewed 161 patients, from four centres in Switzerland, who had undergone posterior fusion of the upper cervical spine with transarticular screw fixation of the atlanto-axial joints. They were followed up for a mean 24.6 months. The vertebral artery and the medulla escaped injury and only 5.9% of the complications were directly related to the screws. The rate of pseudarthrosis was 0.6%.

The course of chronic subdural hematomas after burr-hole craniostomy with and without closed-system drainage.

The author provides a comprehensive review of the results of surgical treatment of chronic subdural hematomas (CSHs). The postoperative clinical course of CSH is studied with respect to the influence of neomembranous organization, cortical expansion, and subdural pressure. The importance of subdural drainage is emphasized.

Immunocytochemical evidence of progesterone receptors in human meningiomas.

The presence of progesterone receptors in meningioma tissue is demonstrated by use of highly specific monoclonal antibodies against the rabbit progesterone receptors which cross-react with human progesterone receptors in breast cancer cells, thus giving evidence of the existence of genuine progesterone receptors in human meningiomas.

Endocrine manipulation of meningiomas with medroxyprogesterone acetate. Effect of MPA on growth of primary meningioma cells in monolayer tissue culture.

Intracranial meningiomas from patients treated with medroxyprogesterone acetate as well as from untreated patients were studied in monolayer tissue culture with trials of in vitro hormonal modulation with medroxyprogesterone acetate. The following conclusions were drawn from investigations which comprise 37 cell culture assays: (a) tissue cultures of meningiomas inherit the disadvantages of loss of the progesterone receptor and frequent transformation to cells resembling fibroblasts after three to four passages. For these reasons, drug testing as well as the establishment of cell cultures that exhibit the characteristics of meningioma are impeded; (b) the progesterone receptor-content of the solid tumors does not reflect the response to medroxyprogesterone acetate-therapy in vitro; (c) medroxyprogesterone acetate-pretreated meningiomas showed sufficient in vitro growth in 38%, and untreated meningiomas grew well in 56% of the cases; (d) medroxyprogesterone acetate-induced inhibition or delay of growth was observed in 35%. These findings have resulted in criticism with respect to the value of meningioma tissue cultures for trials of hormonal manipulation and it is thought that another method, which consists of immunostaining of cycling cells, and has been tested in another study, may be superior to cell culture assays with respect to evaluation of the effect of hormonotherapy in meningiomas. Medroxyprogesterone acetate holds an interesting position because it reduces cell growth in some meningiomas in vitro.

Intracerebral ciliated epithelial cyst.

The authors describe a case of hemispheric brain cyst of possible neuroectodermal origin, presenting as a frontotemporoparietal mass lesion. The etiologic aspects of intracranial neuroepithelial cysts are discussed.

Intracranial ciliated neuroepithelial cyst mimicking arachnoid cyst.

We report a rare case of a left frontal ciliated neuroepithelial cyst that fulfilled all criteria (except histological) of an arachnoid cyst. The literature is reviewed, and the possible pathogenetic mechanisms of subarachnoid ependymal cysts are discussed.

Estrogen and progestin receptors in acoustic and spinal neurilemmomas. Clinicopathologic correlations.

Estradiol and progestin receptors were studied in 20 patients with neuraxial Schwann cell tumors, and their presence was correlated to the clinicopathologic features and the amount of preoperative corticosteroid therapy. Based on an arbitrary cutoff value of 200 fmol per gram of tumor as indicative of a positive receptor value in breast cancer, 4 and 13 of the neurilemmoma tissue samples could be considered as positive for estrogen and progesterone receptors, respectively. Whereas there was no convincing correlation between the estrogen and progestin receptor activity and the age, sex, or menopausal status of the patients, overweight patients had significantly higher estrogen and progestin binding values. The correlation between the amount of preoperative prednisone therapy and the amount of [3H]estradiol and [3H]promegestone binding revealed no dose relationship. Correlating [3H]estradiol and [3H]promegestone content with the histologic type of the schwannomas (Antoni types A and B, respectively), we were not able to draw conclusions, because of the predominance of Antoni type A over Antoni type B tissues in our material. The necessity of nuclear receptor assays, ligand specificity testing, and in vitro studies is stressed as a prerequisite for answering the questions whether neurilemmomas contain genuine sexual steroid hormone receptors and whether these receptors are regulated via an estrogen-estrogen-receptor system as is the case in classical sexual steroid hormone target tissues.

Endocrine manipulation of meningiomas with medroxyprogesterone acetate. Effect of MPA on receptor status of meningioma cytosols.

Fifteen patients with intracranial or spinal meningiomas have been treated with the semisynthetic progestational agent medroxyprogesterone acetate (MPA, Depo-Provera) prior to surgical removal of the tumors in order to investigate the influence of MPA on the progesterone receptor (PR) status of meningioma cytosols. MPA acted as a competitive binder to meningioma-PR: The mean PR values were 15.6 fmol/mg protein (range 0-69) and 338.3 fmol/g tumor (range 0-1190), respectively. In comparison, mean PR values of our untreated meningioma series (n = 58) were 54.9 fmol/mg protein (range 0-586) and 2813 fmol/g tumor (range 0-17,168), respectively. In cases of two-stage resection of meningiomas MPA significantly decreased PR activity in the cytoplasm of meningioma cells. We conclude that MPA binds to meningioma PRs, however, its effect on the growth rate of meningiomas has still to be elucidated.

Estrogen and progesterone receptors in meningiomas in relation to clinical and pathologic features.

Tumor estradiol and progesterone binding sites were studied in 34 patients with meningioma. Twenty of the meningiomas contained very low titers (mean, 45 fmol/g of tumor; range, 0-201 fmol/g of tumor) of a nonspecific cytoplasmic [3H]estradiol binding component, whereas 26 of the tumors contained high titers of specific high-affinity cytosol [3H]promegestone (R5020; progesterone) binding sites (mean, 1476 fmol/g of tumor; range, 0-8328 fmol/g of tumor). No nuclear binding activity for [3H]estradiol could be detected in 12 of the 34 meningiomas studied, irrespective of the progesterone binding activity. There was no correlation between high progesterone binding activity and the age or the sex of the patient, nor between tumor location and cellular mitotic index. However, progesterone binding activity was present more frequently in meningothelial (95%, 18/21 patients) than in transitional (55%, 5/9 patients) or fibroplastic (25%, 1/4 patients) tumor histologic types. These data suggest that the cellular biosynthesis of the progesterone binding component in meningiomas is not estrogen regulated as it is in other classic estrogen target tissues, such as the breast.

Antiestrogenic therapy of meningiomas--a pilot study.

Six patients with inoperable, nonoperative, or recurrent meningiomas were treated with the antiestrogenic agent tamoxifen (Nolvadex) during an 8-12-month period. Computer tomographic, scintigraphic, and clinical evidence of an unspecific tumor response was only encountered in one patient after 4 months of therapy with tamoxifen. The 2-year results did not indicate a favorable response to antiestrogenic treatment. The significance of sex-steroid receptors and their possible prognostic value in endocrine therapy of meningiomas is discussed.

Primary intraventricular oligodendrogliomas.

Two cases of primary intraventricular oligodendrogliomas which were successfully removed by a transventricular approach using microtechniques are presented. Oligodendrogliomas in this location are very rare. The literature is reviewed.