Attenuation numbers of various organic liquids were measured in a phantom at the low and high X-ray beam settings of the Mark I and CT 1010. The readings were translated into absolute units and ratios computed. There is a nonlinear relationship between this ratio and the effective atomic number of the compounds tested. A ratio of one defines a substance with energy dependence like water. Ratios below one definite anhydrous substances composed of elements with low atomic numbers. Ratios greater than one defined substances containing elements with high atomic numbers.

Technology, Radiologic↗

PubMedDate not supplied

Massive doses of steroids in cryogenic cerebral injury and edema.

Cryogenic lesions were produced in the brains of rhesus monkeys and the accompanying edema measured by quantitative chemical methods. No effect on this type of edema could be demonstrated in animals treated with massive doses of steroids.

Animals↗

PubMedDate not supplied

Silent corticotroph adenoma: case report and literature review.

OBJECTIVE: To review the initial clinical manifestations and diagnosis of silent corticotroph adenoma. METHODS: We report a case and summarize the relevant literature. RESULTS: A 52-year-old patient with hypopituitarism underwent resection of a silent corticotroph adenoma. A circulating species was detected postoperatively, reactive in a highly sensitive adrenocorticotropic hormone (ACTH) 1-39 immunoradiometric assay (IRMA) and beta-endorphin or beta-lipotropin radioimmunoassay. The basal morning cortisol concentration consistently was <10 microg/dL. Dynamic testing was performed to screen for Addison's disease, congenital adrenal hyperplasia, and Cushing's syndrome. During dexamethasone suppression, the molar concentration of circulating ACTH precursors by a two-site IRMA was 55-fold greater than the concentration of ACTH 1-39 by IRMA. We concluded that the tumor displayed impaired processing of pro-opiomelanocortin (POMC) and secreted a bioinactive POMC-derived peptide that was reactive in the ACTH 1-39 IRMA. CONCLUSION: Patients with silent corticotroph adenoma do not have clinically evident Cushing's syndrome. In some cases, bioinactive ACTH precursors may be detected by a sensitive ACTH 1-39 IRMA.

Journal Article↗

PubMedDate not supplied

Severe cerebral damage in ornithine transcarbamylase deficiency.

Two patients are described with hyperammonemia due to ornithine transcarbamylase (OTC) deficiency who suffered severe shrinkage and collapse of the brain. The cerebral cortex was spongy and cavitated, containing only a few residual neurons, and was markedly gliosed. In one patient the basal ganglia were affected and harbored Alzheimer type II astrocytes. These lesions resemble those of acquired hepatocerebral degeneration and occur especially in female children with the milder form of the disease, who have a potential to survive. Strict observance of dietary restrictions is mandatory to avoid catastrophic damage to the brain.

Ammonia↗