Pheochromocytoma manifesting with shock presents a clinical paradox: a case report

A 46-year-old man presented with shock and adult respiratory distress syndrome. Investigations revealed an adrenal mass that was diagnosed, by fine-needle aspiration biopsy, as pheochromocytoma. Because biopsy is contraindicated in patients with pheochromocytoma, this confusing presentation underscores the value of excluding this diagnosis by biochemical means before performing fine-needle aspiration of adrenal tumours.     

Effects of MR imaging on murine natural killer cell cytotoxicity

To determine the effect of MR imaging on the immune system, 21 male C57BL/6 X DBA/2 F1 mice were exposed to MR imaging at a field strength of 0.15 T for 2 hr. Another nine mice (controls) were sham exposed for the same amount of time. Mice were sacrificed and their spleens removed 24, 72, and 144 hr after the exposure (MR or sham). Spleen cell suspensions were passed over nylon wool columns and then used as effector cells in a short-term natural killer cell cytotoxicity assay with 51Cr-labeled YAC-1 cells as target cells. The results showed no evidence of decreased cytotoxicity due to exposure to MR. On the contrary, at all three times after exposure and for all target-to-effector cell ratios, mean cytotoxicity was greater for MR-exposed groups than for sham-exposed groups. The results show that MR exposure has no adverse effect on the immune system, as evidenced by natural killer cell activity.     

Cypress (Cupressus sempervirens) pollen allergens: identification by protein blotting and improved detection of specific IgE antibodies

On the basis of results of an investigation of the effects of different treatments employed, a dialysed and reduced extract of Cupressus sempervirens was separated electrophoretically on sodium dodecylsulphate-polyacrylamide gels before being transferred and then fixed with glutaraldehyde to nitrocellulose membrane. Probing with sera from 91 subjects allergic to C. sempervirens pollen followed by detection of bound IgE antibodies with [125I]-labelled anti-human IgE revealed 17 IgE-binding proteins in the molecular weight range 14-96 kilodaltons (kDa). One component, of molecular weight approximately 42 kDa, reacted with IgE antibodies in the sera of 81.3% of the allergic subjects and, for each of the subjects, this component bound the greatest quantity of IgE. Almost 50% of the sera recognized only the approximately 42 kDa component, reinforcing the conclusion that this component is the major allergen of C. sempervirens pollen. A comparative study employing C. sempervirens pollen allergen discs prepared commercially or in the laboratory showed that values of the uptakes of [125I]-anti-IgE indicating the presence of pollen-reactive IgE antibodies obtained with the latter discs were consistently higher (means 4.5 vs. 0.88), and that false-negative results were obtained when many sera were used with the commercial discs. The results of this study provide an essential basis for the production of standardized, safe and effective C. sempervirens pollen extract applicable to diagnosis and therapy of cypress pollen allergy.     

Normative data of hemoglobin concentration and free erythrocyte protoporphyrin in a private pediatric practice: a 1990 update

Free erythrocyte protoporphyrin (FEP) and hemoglobin (Hgb) concentrations were tested in 790 children in a private pediatric office; results were compared to those obtained in 1984. Only 16 children (2%) had abnormal FEPs in 1990 compared to 76 children (9.6%) in the earlier study. The mean FEP in the normal group also decreased significantly in each age group studied. The hemoglobin concentrations were not significantly different in most of the age groups studied. Screening for iron deficiency in our pediatric practice by determining hemoglobin and FEP concentrations had a much lower yield in 1990 than in 1984.     

Large-scale identification of mammalian proteins localized to nuclear sub-compartments

Many nuclear components participating in related pathways appear concentrated in specific areas of the mammalian nucleus. The importance of this organization is attested to by the dysfunction that correlates with mis-localization of nuclear proteins in human disease and cancer. Determining the sub-nuclear localization of proteins is therefore important for understanding genome regulation and function, and it also provides clues to function for novel proteins. However, the complexity of proteins in the mammalian nucleus is too large to tackle this on a protein by protein basis. Large-scale approaches to determining protein function and sub-cellular localization are required. We have used a visual gene trap screen to identify more than 100 proteins, many of which are normal, located within compartments of the mouse nucleus. The most common discrete localizations detected are at the nucleolus and the splicing speckles and on chromosomes. Proteins at the nuclear periphery, or in other nuclear foci, have also been identified. Several of the proteins have been implicated in human disease or cancer, e.g. ATRX, HMGI-C, NBS1 and EWS, and the gene-trapped proteins provide a route into further understanding their function. We find that sequence motifs are often shared amongst proteins co-localized within the same sub-nuclear compartment. Conversely, some generally abundant motifs are lacking from the proteins concentrated in specific areas of the nucleus. This suggests that we may be able to predict sub-nuclear localization for proteins in databases based on their sequence.     

Regulation of renin gene expression in kidneys of eNOS- and nNOS-deficient mice

Our study aimed to assess the roles of nitric oxide derived from endothelium NO-synthase (eNOS) and macula densa neuronal NO-synthase (nNOS) in the regulation of renal renin expression. For this purpose renin mRNA levels and renin content were determined in kidneys of wild-type (wt), nNOS-deficient (nNOS-/-), and eNOS-deficient (eNOS-/-) mice, in which the renin system was suppressed by feeding a high-salt diet (NaCl 4%), or was stimulated by feeding a low-salt (NaCl 0.02%) diet together with the converting-enzyme inhibitor ramipril (10 mg kg(-1) day(-1)). In all mouse strains, renin mRNA levels were inversely related to the rate of sodium intake. In eNOS-/- mice renin mRNA levels and renal renin content were 50% lower than in wt mice at each level of salt intake, whilst in nNOS-/- mice renin expression was not different from wt controls. Administration of the general NO-synthase inhibitor nitro-L-arginine methyl ester (L-NAME, 50 mg kg(-1) day(-1)) to mice kept on the low-salt/ramipril regimen caused a decrease of renal renin mRNA levels in wt and nNOS-/- mice, but not in eNOS-/- mice. These observations suggest that neither eNOS nor nNOS is essential for up- or downregulation of renin expression. eNOS-derived NO appears to enhance renin expression, whereas nNOS-derived NO does not.     

Calorie restriction extends yeast life span by lowering the level of NADH

Calorie restriction (CR) extends life span in a wide variety of species. Previously, we showed that calorie restriction increases the replicative life span in yeast by activating Sir2, a highly conserved NAD-dependent deacetylase. Here we test whether CR activates Sir2 by increasing the NAD/NADH ratio or by regulating the level of nicotinamide, a known inhibitor of Sir2. We show that CR decreases NADH levels, and that NADH is a competitive inhibitor of Sir2. A genetic intervention that specifically decreases NADH levels increases life span, validating the model that NADH regulates yeast longevity in response to CR.