Anomalous responses to stimulation and suppression tests in Cushing's syndrome due to a calcified adrenal adenoma

A case of Cushing's syndrome, due to an adrenal adenoma, which responded to dexamethasone with a rise in plasma urinary steroids is described. Further unusual features were radiologically visible calcification and a response to ACTH stimulation.

Pituitary apoplexy in five patients with pituitary tumours

Five cases of pituitary apoplexy occurring in patients with pituitary tumours are described. This uncommon condition is characterized by headache, sudden loss of vision, alteration in the level of consciousness, and usually an abnormal cerebrospinal fluid. The whole picture may be complicated by endocrine dysfunction. The diagnosis is strengthened by a radiologically abnormal pituitary fossa and confirmed by the operative finding of haemorrhagic necrotic tissue. Surgical decompression under steroid cover offers the only hope of restoration of vision. Frequent postoperative follow-up is obligatory.

Two categories of c/c ratios for higher plants

(13)C/(12)C ratios have been determined for plant tissue from 104 species representing 60 families. Higher plants fall into two categories, those with low delta(PDBI) (13)C values (-24 to -34 per thousand) and those with high delta (13)C values (-6 to -19 per thousand). Algae have delta (13)C values of -12 to -23 per thousand. Photosynthetic fractionation leading to such values is discussed.

Biogeochemistry of the stable isotopes of hydrogen and carbon in salt marsh biota

Deuterium to hydrogen ratios of 14 plant species from a salt marsh and lagoon were 55 per thousand depleted in deuterium relative to the environmental water. Carbon tetrachloride-extractable material from these plants was another 92 per thousand depleted in deuterium. This gave a fractionation factor from water to CCl(4) extract of 1.147. This over-all fractionation was remarkably constant for all species analyzed. Plants also discriminate against (13)C, particularly in the lipid fraction. Data suggest that different mechanisms for carbon fixation result in different fractionations of the carbon isotopes. Herbivore tissues reflected the isotopic ratios of plants ingested. Apparently different metabolic processes are responsible for the different degrees of fractionation observed for hydrogen and carbon isotopes.

Antarctic Ice Sheet: Stable Isotope Analyses of Byrd Station Cores and Interhemispheric Climatic Implications

Oxygen- and hydrogen-isotope analyses from the core hole through the Antarctic Ice Sheet at Byrd Station define temperature variations over more than 75,000 years. Synchronism between major climatic changes in Antarctica and the Northern Hemisphere is strongly indicated. The Wisconsin cold interval extended from 75,000 to 11,000 years ago. Three intra-Wisconsin warmer phases were all colder than pre- or post-Wisconsin times, which suggests that North American and Eurasian continental ice sheets did not disappear at any time during the Wisconsin.

18 O/ 16 O, 30 Si/ 28 Si, D/H, and 13 C/ 12 C Studies of Lunar Rocks and Minerals

The delta (18)O of minerals from lunar gabbros and basalts are: plgioclases +6.06 to +6.33), pyroxenes (+5.70 to +5.95), and ilmenites (+3.85 to +4.12). The uniformity of these results indicates isotopic equilibrium in the mineral assemblages. Estimated plagioclase-ilmenite temperautres range from 1150 degrees C to 1340 degrees C. The bulk (18)/ (16)O and (30)Si/ (28)Si ratios of these lunar rocks are identical with ratios of terrestrial basalts, but the lunar glass, breccia, and dust are slightly enriched in the heavier isotopes. The lunar hydrogen (formed from solar wind) has a delta D/H of less than-873 per mil and the value may be even lower, as it is probably contaminated with terrestrial hydrogen. The delta (13)C of lunar dust and breccia is unusually high relative to reduced carbon in meteorites or on earth.

The prevalence of carbon-13 in respiratory carbon dioxide as an indicator of the types of endogenous substrate. The change from lipid to carbohydrate during the respiratory rise in potato slices

Isotope discrimination is a common feature of biosynthesis in nature, with the result that different classes of carbon compounds frequently display different (13)C/(12)C ratios. The (13)C/(12)C ratio of lipid in potato tuber tissue is considerably lower than that for starch or protein. We have collected respiratory CO(2) from potato discs in successive periods through 24 hr from the time of cutting-an interval in which the respiration rate rises 3-5-fold. The (13)C/(12)C ratio of the evolved CO(2) was determined for each period, and compared with the (13)C/(12)C ratios of the major tissue metabolites. In the first hours the carbon isotope ratio of the CO(2) matches that of lipid. With time, the ratio approaches that typical of starch or protein. An estimation has been made of the contribution of lipid and carbohydrate to the total respiration at each juncture. In connection with additional observations, it was deduced that the basal, or initial, respiration represents lipid metabolism-possibly the alpha-oxidation of long chain fatty acids-while the developed repiration represents conventional tricarboxylic acid cycle oxidation of the products of carbohydrate glycolysis. The true isotopic composition of the respiratory CO(2) may be obscured by fractionation attending the refixation of CO(2) during respiration, and by CO(2) arising from dissolved CO(2) and bicarbonate preexisting in the tuber. Means are described for coping with both pitfalls.