In the treatment of patients with hypertension and renal-artery stenosis, angioplasty has little advantage over antihypertensive-drug therapy.

To study the metabolism and production of angiotensin I, highly purified monoiodinated [ synthesized mainly by the kidneys, acts on renin substrate (angiotensinogen) to form the decapeptide angiotensin I (Ang I), which is then converted to the octapeptide angiotensin II (Ang II) by angiotensin converting enzyme (ACE). All these components of the renin-angiotensin system are pres-

In approximately 60% of sporadic meningiomas, the tumour suppressor gene NF2, located on chromosome 22q, is inactivated. Mutations in the NF2 gene have been specifically reported in transitional and fibrous, but not meningothelial, meningiomas. Since meningothelial meningiomas frequently occur in anterior parts of the skull base, the association between tumour localization, size, histological subtype and NF2 status was investigated in a group of 42 sporadic meningiomas. NF2 status was determined by LOH analysis, karyotyping and FISH. Tumour size and site were evaluated by CT scans and MRIs. A strong correlation between tumour localization in the anterior skull base and intact 22q was revealed (p=0.003). On the other hand, tumour localization at the convexity was associated with disruption of NF2 (p=0.023). Furthermore, an association between chromosome 22 status and histological subtype was observed: abnormalities of chromosome 22q were more frequent in transitional and fibrous meningiomas than in the meningothelial variant (p<0.001). Also, the meningothelial meningiomas were more often located in the anterior skull base (p<0.006). Based on these findings, it is concluded that an alternative histogenesis and genetic pathway is likely to exist for meningiomas arising in the anterior skull base.

In craniofacial surgery, alloplastic materials are used for correcting bony defects. Porous polymethylmethacrylate (PMMA) is a biocompatible and nondegradable bone cement. Porous PMMA is formed by the classic bone cement formulation of methylmethacrylate liquid and PMMA powder in which an aqueous biodegradable carboxymethylcellulose gel is dispersed to create pores in the cement when cured. Pores give bone the opportunity to grow in, resulting in a better fixation of the prostheses. We evaluated the long-term results (n = 14), up to 20 years, of augmentations and defect fillings in the craniofacial area, with special interest in possible side effects and bone ingrowth. The evaluation consisted of a questionnaire, a physical examination, and a computed tomography (CT) scan. There were no side effects that could be ascribed to the porous PMMA. Twelve CT scans showed bone ingrowth into the prostheses, proving the validity behind the concept of porous PMMA.

Bilateral simultaneous inferior petrosal sinus blood sampling for plasma ACTH measurements before and after CRH stimulation successfully confirmed the diagnosis of pituitary dependent Cushing's disease in 15 of 17 patients (88%) in whom this diagnosis was suspected on the basis of conventional biochemical testing. Magnetic resonance imaging, however, is superior to bilateral simultaneous inferior petrosal sinus blood sampling for the localization/lateralization of pituitary microadenomas in patients with Cushing's disease. Therefore, bilateral simultaneous inferior petrosal sinus blood sampling should be reserved for the assessment of those patients with Cushing's syndrome in whom either the results of biochemical tests are equivocal and/or subsequent pituitary magnetic resonance imaging gives unconvincing results.