Erythrocyte ferritin in patients with chronic renal failure and heterozygous beta-thalassemia.

Aim: The aim of this research is to study the variance of erythrocyte ferritin (EF) in patients with chronic renal failure (CRF) and heterozygous beta-thalassemia (beta-TA), as well as the use of EF as a more reliable index for assessing the body iron status.

Methods: We studied 63 subjects with CRF, 40 subjects with heterozygous beta-TA, 53 subjects with CRF and heterozygous beta-TA and 24 normal subjects. In 11 patients with CRF and heterozygous beta-TA, sternal bone marrow aspiration was performed to evaluate iron stores in the bone marrow.

A T42A Ran mutation: differential interactions with effectors and regulators, and defect in nuclear protein import.

Ran, the small, predominantly nuclear GTPase, has been implicated in the regulation of a variety of cellular processes including cell cycle progression, nuclear-cytoplasmic trafficking of RNA and protein, nuclear structure, and DNA synthesis. It is not known whether Ran functions directly in each process or whether many of its roles may be secondary to a direct role in only one, for example, nuclear protein import. To identify biochemical links between Ran and its functional target(s), we have generated and examined the properties of a putative Ran effector mutation, T42A-Ran.

The small nuclear GTPase Ran: how much does it run?

Ran is one of the most abundant and best conserved of the small GTP binding and hydrolyzing proteins of eukaryotes. It is located predominantly in cell nuclei. Ran is a member of the Ras family of GTPases, which includes the Ras and Ras-like proteins that regulate cell growth and division, the Rho and Rac proteins that regulate cytoskeletal organization and the Rab proteins that regulate vesicular sorting.

Tissue-specific expression of Ran isoforms in the mouse.

Ran genes encode a family of well-conserve small nuclear GTPases (Ras-related nuclear proteins), whose function is implicated in both normal cell cycle progression and the transport of RNA and proteins between the nucleus and the cytoplasm. Previous studies of Ran proteins have utilized cell-free systems, yeasts, and cultured mammalian cells. We have now characterized patterns of Ran gene expression in the mouse.

Aberrant function of the Ras-related protein TC21/R-Ras2 triggers malignant transformation.

Although the human Ras proteins are members of a large superfamily of Ras-related proteins, to date, only the proteins encoded by the three mammalian ras genes have been found to possess oncogenic potential. Among the known Ras-related proteins, TC21/R-Ras2 exhibits the most significant amino acid identity (55%) to Ras proteins. We have generated mutant forms of TC21 that possess amino acid substitutions analogous to those that activate Ras oncogenic potential [designated TC21(22V) and TC21(71L)] and compared the biological properties of TC21 with those of Ras proteins in NIH 3T3 and Rat-1 transformation assays.

Ran/TC4: a small nuclear GTP-binding protein that regulates DNA synthesis.

Ran/TC4, first identified as a well-conserved gene distantly related to H-RAS, encodes a protein which has recently been shown in yeast and mammalian systems to interact with RCC1, a protein whose function is required for the normal coupling of the completion of DNA synthesis and the initiation of mitosis. Here, we present data indicating that the nuclear localization of Ran/TC4 requires the presence of RCC1. Transient expression of a Ran/TC4 protein with mutations expected to perturb GTP hydrolysis disrupts host cell DNA synthesis.

Evolutionary grouping of the RAS-protein family.

Over 50 proteins related to the mammalian H-, K-, and N-RAS GTP binding and hydrolyzing proteins are known. These relatively low molecular weight proteins are usually grouped into four subfamilies, termed true RAS, RAS-like, RHO, and RAB/YPT, based on the presence of shared amino acid sequence motifs in addition to those involved in guanine nucleotide binding. Here, we apply parsimony analysis to the overall amino acid sequences of these proteins to infer possible phylogenetic relationships among them.

Identification and characterization of a human homolog of the Schizosaccharomyces pombe ras-like gene YPT-3.

The Polymerase Chain Reaction was used to amplify ras and ras-like sequences from two human cDNA libraries. Members corresponding to each of the three major ras-subfamilies (ras, rho, and rab/YPT) were identified. The one homologous to rab/YPT, referred to here as YL8, appears to be the human homolog of the recently reported Schizosaccharomyces pombe YPT3 gene.

Ras-like genes and gene families in the mouse.

Four human RAS-like cDNAs and a mouse genomic DNA fragment were used to define novel mouse Ras-like genes and gene families. Inheritance of DNA restriction fragment length variants associated with these genes in recombinant inbred and backcross mice allowed definition of 12 genetic loci, nine of which were mapped, to chromosomes (Chr) 2, 4, 7, 8, 9, and 17. Two possible clusters of Ras-like and/or G protein genes were identified, on Chrs 9 and 17.

Characterization of four novel ras-like genes expressed in a human teratocarcinoma cell line.

A mixed-oligonucleotide probe was used to identify four ras-like coding sequences in a human teratocarcinoma cDNA library. Two of these sequences resembled the rho genes, one was closely related to H-, K-, and N-ras, and one shared only the four sequence domains that define the ras gene superfamily. Homologs of the four genes were found in genomic DNA from a variety of mammals and from chicken.

Comparative study between iohexol and iopromide for aortofemoral arteriography.

A double-blind clinical trial was performed on 50 patients in order to compare omnipague (iohexol) and Ultravist-300 (iopromide) for peripheral arteriography. Both contrast media were well tolerated, but there was less body heat and pain in the Ultravist group. There were no idiosyncratic reactions or significant changes in blood pressure before and after the injection.

Is there a "gold standard" for human serum vitamin B12 assay?

In a study from four laboratories using two commercial vitamin B12 radioassays (impure hog intrinsic factor concentrate containing both intrinsic factor and R binders (IF + R) to measure total corrinoids and the same concentrate presaturated with cobinamide (Cbi) to block B12 binding sites on R binder (IF + R + Cbi) to measure only cobalamins), the rank order of results was generally the same. The concordance between the two tests for classifying sera as normal or deficient was 91% in 311 serum samples. Three percent of sera below the "true B12" (B12 binding to IF + R + Cbi) normal cut-off point were not below the cut-off point for normal "total B12" (B12 binding to IF + R); 6% of sera below the total B12 normal cut-off point were not below true B12 cut-off point.

A simultaneous study of the polymorphism of five proteins in the serum and the urine of nephrotic patients.

The phenotypes of the haptoglobin (Hp), ceruloplasmin (Cp), group-specific component (Gc), transferrin (Tf), and third component of complement (C3) were determined simultaneously in the serum and urine of patients with proteinuria secondary to nephrotic syndrome of various types. In a large number of cases the patterns of Hp, Cp, and C3 phenotypes in the urine showed marked deviations from those in the corresponding serum either in the mobility or the number of their electrophoretic bands. The monomeric Hp and the Cp were found to have a very augmented urine/serum ration in some cases.

Serum and erythrocyte glutathione reductase activity in chronic renal failure.

The activity of serum and erythrocyte glutathione reductase was studied in 66 undialysed uremic patients, 19 patients under treatment by chronic hemodialysis and 38 normal subjects. A statistically significant increase of the enzyme activity was found both in serum and erythrocytes in the uremic patients. This increase was in positive correlation with blood urea and creatinine.