Pattern of cerebral aneurysms in Morocco: review of the concept of their rarity in developing countries: report of 200 cases.

OBJECTIVE: Many neurosurgeons consider cerebral aneurysms to be rare in Africa and the Middle East. In this report, we describe the pattern of cerebral aneurysms in Morocco and call into question the idea of their rarity in developing countries. Our objective is to urge neurosurgeons in these areas to track them and to treat them under better conditions. METHODS: We report a retrospective study of 200 patients with cerebral aneurysms admitted to our department between 1983 and 1999. The results of this study are supported by pertinent epidemiological surveys, anatomic studies on the incidence of cerebral aneurysms in Morocco, and analysis of the literature related to the epidemiology of aneurysms in developing countries. RESULTS: The patients in our series ranged in age from 7 to 70 years (mean age, 52 yr), with a slight female predominance (52%). They presented with subarachnoid hemorrhage (173 patients), cranial nerve palsy (18 patients), or mass symptoms (9 patients). The delay between subarachnoid hemorrhage and admission ranged from 1 to 30 days (mean, 14 d). The aneurysm was located in the internal carotid artery in 42%, in the anterior communicating and anterior cerebral arteries in 28%, in the middle cerebral artery in 19%, and in the vertebrobasilar artery in 10%. Multiple aneurysms were encountered in 9% and giant aneurysms in 15.5%. Seventeen patients died before surgery (with vasospasm in 13 cases and rebleeding in 4 cases), and 19 died after surgery. Follow-up, ranging between 1 and 10 years, revealed good outcomes with complete recovery in 64.5% and recovery with major sequelae in 7%. Pre- and postoperative mortality represented 18%; there was no operative treatment and no follow-up in 11.5%. CONCLUSION: Some data in this study (the delay between subarachnoid hemorrhage and admission, the high incidence of urban patients [80%], and the high rate of giant aneurysms) explain why many cases of ruptured aneurysms are not diagnosed. The analysis of our clinical series and the results of the epidemiological surveys show that the incidence has doubled every 5 years. These findings confirm that cerebral aneurysms are not rare in Morocco. A critical reading of the published articles claiming a low incidence of cerebral aneurysms in Africa, the Middle East, and Asia shows that this conclusion is not based on accurate and reliable statistical studies. Neurosurgeons in these regions should abandon this idea of rarity, and they should search for arterial cerebral aneurysms and develop the optimum conditions for the treatment of patients with aneurysms.

The effect of prolactin and bombesin on the growth of meningioma-derived cells in monolayer culture.

Meningioma growth is thought to be stimulated by the sex hormones progesterone and possibly estrogen. We report here stimulation of growth of meningioma-derived cells in culture by prolactin. Fourteen human tumors taken from surgery were initially grown in Ham's medium F10 with 15% fetal calf serum. The tumors were then trypsinized and resuspended in medium in a multi-well plate with either prolactin or bombesin; the cells were incubated for 1 week, washed, and resuspended for cell counting. The growth-stimulating effect of prolactin at 10 and 200 micrograms/ml was compared with bombesin at 5 mM/ml or 15 mM/ml. A growth index compared cell count in the experimental well to the control well; growth at the rate of the control well was given an index of 1.0. The tumors included 7 meningiomas and 7 other neoplasms (3 astrocytomas, an ependymoma, a pineoblastoma, a hemangiopericytoma, and a metastatic adenocarcinoma). For meningiomas incubated in 10 micrograms/ml prolactin, the growth index was 3.08; for those incubated in 200 micrograms/ml prolactin, it was 2.28. Bombesin indices were 1.7 and 1.2 at 5 mM/ml and 15 mM/ml, respectively. By 2-tailed t-testing both prolactin concentrations stimulated the growth of meningiomas significantly (P < or = 0.02), while bombesin did not. Neither peptide enhanced the growth of the other tumors tested.

Intracranial epidermoid tumors. A continuing diagnostic challenge.

Epidermoid tumors are benign, slowly growing intracranial masses that still present difficulty in preoperative diagnosis. This article reviews six cases of histologically proven epidermoid tumors. Computed tomography and magnetic resonance imaging were complementary in their evaluation. Computed tomography demonstrated a hypodense, smoothly contoured extra-axial paramedian mass with lower density than cerebrospinal fluid. Magnetic resonance imaging usually demonstrated an irregularly but sharply marginated mass with inhomogeneous density, variable enhancement with gadolinium, lack of edema in adjacent normal structures, extensive insinuation into cisternal and other cerebrospinal fluid spaces, and a high-signal intensity on proton-weighted images. Multiplanar magnetic resonance imaging was extremely helpful in displaying the full anatomic extent of the lesion and its relationship with other structures.

Estrogen increases galanin immunoreactivity in hyperplastic prolactin-secreting cells in Fisher 344 rats.

Galanin is a widely distributed regulatory peptide which modulates the pituitary secretion of PRL and GH. Estrogen administration strongly stimulates galanin gene expression in the rat anterior pituitary. In adult female Fischer 344 rats, estrogen also induces hyperplasia of lactotropes. We used immunocytochemical analysis to assess the effects of estrogen on galanin-like immunoreactivity (Gal-IR) in the rat pituitary and hypothalamus during sc diethylstilbestrol (DES) implantation and after its removal at 30 days. In the anterior pituitary, DES implantation increased the portion of Gal-IR-containing cells from less than 2% in the control rats to 18.3% after 3 days of DES and 36% after 30 days. These changes paralleled the lactotrope hyperplasia exhibited in response to DES exposure. Ten and 30 days after removal of the DES capsules, the percentage of Gal-IR-containing cells in the anterior pituitary decreased to 6.3% and 1.5%, respectively. Colocalization studies revealed that Gal-IR-containing cells were predominantly lactotropes. Immunoelectron microscopy demonstrated that Gal-IR was concentrated in the Golgi region of these hyperplastic lactotropes and suggests that little of the synthesized galanin is secreted. The distribution of Gal-IR in the hypothalamus, median eminence, and neurohypophysis was unaffected by DES treatment. These data demonstrate that galanin is synthesized by hyperplastic pituitary lactotropes of Fischer 344 rats and that peptide accumulation is dependent on the presence of circulating estrogens. In contrast, neuronal galanin synthesis in the hypothalamus does not appear to be regulated by estrogen.

Transsphenoidal surgery for visual loss in patients with pituitary adenomas.

This paper presents the results of transsphenoidal surgery in 41 consecutive patients with visual loss from pituitary adenomas. The most common pattern of loss was bitemporal hemianopia. Transsphenoidal decompression resulted in visual improvement in 78% of patients. If patients with optic atrophy and pre-operative complete blindness were excluded, improvement extended to 94% of patients. Because of its efficacy and low morbidity, transsphenoidal resection of pituitary tumours is the procedure of choice for most adenomas with extrasellar extension and visual field loss.

The importance of dopamine in the pathogenesis of experimental prolactinomas.

The factors responsible for the production of prolactin-secreting tumors are obscure. One hypothesis, that chronic loss of dopamine control from the hypothalamus may be associated with prolactinoma formation, was tested. Female adult Fischer 344 rats were subjected to ovariectomy and were then given subcutaneous implants of diethylstilbestrol (DES) Silastic capsules to produce lactotrophic hyperplasia. Sequential studies assessed the neuronal activity of the tuberoinfundibular dopaminergic neurons of the arcuate nucleus of the hypothalamus (A12) during and after this estrogen-induced pituitary growth. Immunocytochemical staining for tyrosine hydroxylase was used as a marker for dopamine synthesis, plasma radioimmunoassay provided plasma prolactin levels, and magnetic resonance imaging and histological studies were performed to examine the structural changes occurring in the pituitary gland. Animals were sacrificed from 3 to 67 days after DES implantation. To determine the reversibility of the estrogen-induced changes, rats were also sacrificed at different time intervals after the removal of 30-, 40-, or 60-day DES implants. After 30 days of DES treatment, plasma prolactin levels increased 40-fold and pituitary weight increased more than threefold. Tyrosine hydroxylase immunoreactivity diminished gradually and was almost completely depleted at 30 days. Pituitary histology revealed marked prolactin cell hyperplasia. These changes were completely reversible; removal of the capsule after 30 days resulted in eventual normalization of plasma prolactin levels and pituitary size and in restoration of tyrosine hydroxylase immunoreactivity in the A12 region. Sixty days of DES treatment produced large hemorrhagic tumors with sustained high plasma prolactin levels and an irreversibly distorted A12 area. These observations suggest that in these animals loss of dopamine regulation secondary to estrogen stimulation initially produces prolactin hyperplasia but that prolonged loss leads to adenoma formation.

[Harvey Cushing: neurosurgeon and artist]. / Harvey Cushing: neurochirurgien et artiste.

Harvey Cushing was a man of many talents. He was a skilled, surgeon, scientist, author and bibliophile. In addition, he was an accomplished artist for both medical non-medical subjects. In this paper, we present three surgical drawings of Dr Cushing's that are representative of the nearly one hundred drawings we have thus far found with his operative notes in the Peter Bent Brigham Archives. We will also discuss Cushing's non-medical art, some of the best of which is of the French countryside.

Loss of distinct regions on the short arm of chromosome 17 associated with tumorigenesis of human astrocytomas.

Astrocytomas, including glioblastoma multiforme, represent the most frequent and deadly primary neoplasms of the human nervous system. Despite a number of previous cytogenetic and oncogene studies primarily focusing on malignant astrocytomas, the primary mechanism of tumor initiation has remained obscure. The loss or inactivation of "tumor suppressor" genes are thought to play a fundamental role in the development of many human cancers. Thus, we have analyzed astrocytomas of various histological malignancy grades with polymorphic DNA markers to search for specific chromosomal deletions potentially pointing to loci containing tumor suppressor genes. Loss of constitutional heterozygosity indicating chromosomal loss or deletions was most frequently seen for markers on the short arm of chromosome 17 in 50% of the informative tumors (5 of 10 informative cases) and, to a lesser extent, for markers on chromosomes 1 and 10. Deletions on chromosome 17p were seen in both low-grade and high-grade malignant astrocytomas, suggesting that this chromosome may contain a tumor suppressor gene associated with the early events in tumorigenesis. The common region of deletions on the short arm of chromosome 17 is, therefore, clearly distinct from the gene causing von Recklinghausen neurofibromatosis (NF1), a tumor syndrome associated with glial tumors that maps to the long arm of chromosome 17. The search for progressively smaller deletions on chromosome 17p in astrocytomas may be the way to clone and characterize this locus, thus leading to insights into normal and abnormal growth and differentiation of glial cells.

Mucinous cysts of the pituitary stalk. Report of two cases.

This report describes two cases of a mucinous cyst (Rathke's cleft cyst) in the pituitary stalk: the first was found in a 29-year-old woman 5 years following pregnancy and the second in a 30-year-old woman 6 years after pregnancy. The presenting symptoms are analyzed and the diagnosis is discussed, with emphasis on the role of magnetic resonance imaging.

[The concept of suppressor genes in the molecular biology of central nervous system tumors]. / Le concept de gène suppresseur dans la biologie moléculaire des tumeurs du système nerveux central.

Recently, major advances have resulted from the application of molecular biology to the understanding of central nervous system neoplasia. Schematically, two fundamental mechanisms of tumorigenesis have been described: the activation of oncogenes, and the inactivation of so called recessive "tumor suppressor" genes or "anti-oncogenes". The present report deals with the second mechanism. We discuss its basic concept and techniques, and illustrate it by specifc examples of recent work on brain tumors. The goal of this review is to familiarize Neurosurgeons with the terminology and techniques in this field. Molecular genetics suggest that cancer is a molecular disease which involves regulator genes. These play a major role in growth control, differentiation, and physiology. In the near future molecular biology may identify the structure of proteins coded by suppressor genes, possibly allowing a better tumor classification creating a new "genetic therapy", based on a better comprehension of the role of these genes in dividing and differentiating cells.