Pathologically proven cavernous angiomas of the brain following radiation therapy for pediatric brain tumors

Lesions consistent with cavernous angiomas (CAs) of the brain are sometimes seen on MRI scans of the brains of patients who received radiation therapy for brain tumors as children. The lesions appear years later within brain tissue that was included in radiation fields. It is unclear whether these MRI-detected lesions are true CAs or a pathological variant. This study reports the clinical, radiographical, and pathological findings in 3 cases of radiation-induced CAs of the brain. From 1995 to 1997, 3 patients previously treated with radiation therapy (45-55 Gy) for pediatric brain tumors (medulloblastoma, ependymoma, and a presumed midbrain astrocytoma) underwent resections of symptomatic and enlarging lesions that were consistent with a CA of the brain. All of the lesions occurred within fields of prior irradiation. None of the patients had received chemotherapy as part of their cancer treatment. CA-presenting symptoms included seizures, cranial nerve deficits, and headaches. The lesions appeared 7-19 years after radiation therapy and slowly enlarged on subsequent imaging studies. MRI scans of the lesions revealed characteristics typical of CA. The lesions became symptomatic 1-5 years after they were initially noted. Surgical resection was performed 1-2 years after symptoms began. The age at resection ranged from 15 to 23 years (10-21 years after radiation therapy). Pathological analysis of the three lesions showed typical CA characteristics. Some CAs may be caused by radiation therapy for pediatric brain tumors. They are radiologically and pathologically similar to sporadically occurring CAs of the brain and may enlarge over time and become symptomatic. CAs can be safely resected using standard microsurgical techniques.     

beta-amyloid peptide-induced death of PC 12 cells and cerebellar granule cell neurons is inhibited by long-term lithium treatment

Treatment of rat pheochromocytoma cells (PC 12) cells with beta-amyloid peptide-(1-42) for 24 h induced a concentration-dependent decrease in cellular redox activity in the dose range of 1 to 20 microM. These effects were markedly attenuated by pretreatment with 2 mM LiCl for 7 days, whereas 1-day pretreatment was ineffective. Measurements of live and dead cells by double-staining with fluorescein diacetate and propidium iodide, respectively revealed that protracted lithium pretreatment attenuated PC 12 cell death induced by beta-amyloid-(1-42) and cerebellar granule cell death induced by beta-amyloid-(25-35). Preceding PC 12 cell death, beta-amyloid peptide elicited a slight decrease in protein levels of Bcl-2. Conversely, 7-day pretreatment with lithium resulted in an approximate doubling of Bcl-2 protein levels in cells treated with or without beta-amyloid peptide-(1-42). Lithium-induced Bcl-2 upregulation was temporally associated with the cytoprotective effects of this drug. Thus, lithium protection against beta-amyloid peptide neurotoxicity might involve Bcl-2 overexpression, and lithium treatment for Alzheimer's disease should be reexamined.     

Failure of penicillin to eradicate group B streptococcal colonization in the pregnant woman. A couple study.

Prophylactic treatment of couples with oral penicillin has been recommended as a means of eradicating GBS from the parturient female. In 1977 and 1978 this hypothesis was tested in an investigation of couples from a middle and upper socioeconomic group in Houston, Texas. A group of 40 women, known to be colonized with GBS during the third trimester of pregnancy, and their husbands were treated simultaneously with oral penicillin. Patients were recultured 3 weeks following completion of therapy and at the time of delivery. At the time of delivery 67% of the women remained colonized with GBS. This percentage does not differ substantially from that obtained in a series of untreated colonized women. This study demonstrates that oral penicillin treatment of couples is not an effective means of reducing maternal colonization at the time of delivery.     

Volumetric rendering of MR images

The authors developed new techniques for three-dimensional display of magnetic resonance (MR) images that preserve soft-tissue definition, are fully automatic, and work with routinely used section thicknesses. MR images are segmented, selectively enhanced, and displayed by means of a volumetric rendering algorithm. These techniques were used to illustrate normal anatomy of the brain, knee, and liver. Three-dimensional rendering of balanced spin-echo images shows the ventricles and extracerebral veins and of T1-weighted images, the sulci and gyri. The large hepatic and portal vessels can be seen with these enhancement techniques. Three-dimensional views of the knee reveal articular surfaces of the tibia and clearly depict menisci and posterior and anterior cruciate ligaments. These techniques make it possible to image multiple soft tissues simultaneously while preserving the detail contained in the original images. Three-dimensional presentation of complex, overlapping anatomic regions is helpful in surgical planning and should lead to improved diagnosis.     

Tolerance of iohexol, iopamidol, and metrizamide in lumbar myelography

Iohexol and iopamidol, two new nonionic contrast media, have been extensively studied in comparison with metrizamide for lumbar myelography. Review of the literature with statistical analysis indicates both agents are superior to metrizamide in terms of number of patients with adverse reactions (p < 0.001). Preliminary data suggest, but do not prove, that use of iohexol may result in fewer side effects than iopamidol.     

Extraspinal abnormalities identified on lumbar spine CT

Summary Retrospective review of 1517 lumbar CT examinations revealed extraspinal pathology in 22 (1.45%). Retroperitoneal tumors and lymphadenopathy as well as vascular, urinary tract and gynecologic abnormalities were identified. This study demonstrates the need to carefully evaluate the visualized portions of the abdomen and pelvis on all lumbar spine CT examinations even when the patient's symptomatology is suggestive of spinal abnormalities.