Alpha zero-thalassemia due to recombination between the alpha 1-globin gene and an AluI repeat

A form of alpha zero-thalassemia found in subjects of Mediterranean origin has been analyzed by gene mapping and DNA sequencing. Homozygotes have the hemoglobin Bart's hydrops fetalis syndrome, while compound heterozygotes for this defect and alpha+-thalassemia have hemoglobin H disease. It results from a deletion that removes 20.5 kilobases of DNA from within the alpha-globin gene cluster. Sequence data from the regions adjacent to the breakpoint indicate that the recombination event that caused this deletion occurred between the alpha 1-gene and an unusual AluI sequence located between the embryonic zeta genes.     

Purification and characterization of the human neutrophil NADH- cytochrome b5 reductase

NADH-cytochrome b5 reductase is the predominant NADH-diaphorase found in the human neutrophil (Blood 62:152, 1983). Although this reductase segregates with the light membranes of nitrogen-cavitated neutrophils separated on Percoll gradients (which include the plasma membrane markers alkaline phosphatase and NADPH-oxidase), it is approximately 95% excluded from plasma membrane-enriched phagocytic vacuoles. The reductase constitutes approximately 5% of the light membrane fraction FAD-flavoprotein (14.8 +/- 5.5 pmol/mg protein) and was found in equimolar concentration with a high potential b cytochrome also present in this light membrane fraction and tentatively identified as cytochrome b5. Isolation of the reductase from human neutrophils was accomplished by Triton X-114 solubilization of the light Percoll gradient membranes, followed by temperature-dependent phase separation and then affinity chromatography on AMP-Sepharose. The active preparation contained 1.3 mol FAD/mol protein, migrated on sodium dodecyl sulfate-polyacrylamide gels as a single band corresponding to an apparent mol wt of 45,000 daltons, exhibited a pl of 5.7 on chromatofocusing and was obtained in greater than 70% yield, with an overall purification of almost 900-fold. The purified enzyme was characterized by a high specificity for NADH as electron donor (Km = 6.4 mumol/L v Km greater than 1.6 mmol/L for NADPH) and exhibited a maximal turnover of ca. 30,000 min-1 at 22 degrees C with either ferricyanide or cytochrome b5 (Km = 10 nmol/L) as electron acceptor. Although the physical characterization and biochemical properties described here demonstrate that this neutrophil NADH b5 reductase is similar to the corresponding liver and erythrocyte enzymes, its unique function in the neutrophil has yet to be determined.     

Assessing post-traumatic stress disorder in South African adolescents: using the child and adolescent trauma survey (CATS) as a screening tool

Background  

Several studies have demonstrated that South African children and adolescents are exposed to high levels of violent trauma with a significant proportion developing PTSD, however, limited resources make it difficult to accurately identify traumatized children.     

Repression of c-myc gene expression by the thiol and disulfide forms of the cytoprotector amifostine

The clinically approved cytoprotector amifostine, designated WR-2721, [S-2-(3-aminopropylamino)ethylphosphorothioic acid], protects against both radiation and drug-induced mutagenesis in animal systems. These effects extend over a wide concentration range making amifostine a strong candidate for evaluation as a possible cancer chemopreventive agent. To better identify and develop potential intermediate biomarkers for chemoprevention at the molecular level we applied the technique of differential display RT-PCR to assess the effects of both the thiol (SH), i.e. WR1065 and the disulfide (SS), i.e. WR-33278, metabolites of amifostine on gene expression in CHO-AA8 cells. Cells were exposed to either 40 microM or 4 mM of each agent for 30 min, and subsequent changes in gene expression were identified and contrasted to that found in corresponding untreated control cells. One band that showed a differential response was sequenced and was found to have 78% homology with a segment of the human pHL-1 cDNA clone contained in GenBank. This clone contains a COX III mitochondrial DNA insert and two exons of human c-myc. Northern blot analyses were performed by using the cloned human c-myc exon 1 probe to confirm whether c-myc gene expression was affected. Repression of c-myc expression was observed under all of the conditions evaluated. An exposure of cells to 40 microM of the disulfide form of amifostine was the most effective in repressing c- myc, i.e. 27% of control level. A concentration of 4 mM of the disulfide form reduced gene expression to 45% of the control level, while the thiol form was less effective, with 4 mM and 40 microM concentrations reducing c-myc gene expression to 65% and 46% of control levels, respectively.      

HEPATIC ARTERY ANEURYSM: AN UNUSUAL PRESENTATION

SUMMARY The natural history of visceral artery aneurysms, and in particular those of the hepatic artery, is unclear. The clinical presentation can include upper abdominal pain, bleeding into the gastrointestinal tract, and obstructive jaundice. We present the case of a middle-aged woman with right upper quadrant pain and a palpable mass, in whom a thrombosed hepatic artery aneurysm was found to be the cause.     

Clinical interest in determinations of cellular radiation sensitivity

Determinations of cell sensitivity in terms of survival fraction after doses employed in clinical radiation therapy, say 1-3 Gy, are of increasing interest to clinicians as they provide direct experimental data which can be employed without reference to models of cell inactivation. SF2 values are expected ultimately to prove valuable as response predictors. Even so, SF2 values would surely be combined with other predictors also under development to give the best feasible estimate of response of tumor and normal tissue. There are, however, several concerns with the SF2 data currently available. These include: SF2 depends upon the cell system employed (established cell lines vs primary cultures) and the method of assaying survival fraction (colony formation vs population growth); dose-response curves for inactivation of tumors characterized by the reported distribution of SF2 values are, in many instances, not close to those judged to obtain in clinical practice; the broad distribution of SF2 values indicates a rather flatter dose-response curve for tumor control or normal tissue than seems true from clinical experience. There appears to be a potential for clinical gain by determination of sensitivity of normal tissues in order to identify patients who are of increased sensitivity (for example heterozygotes for AT, 5-oxoprolinuria, etc.). Although the absolute SF2 values obtained by current technologies of culturing human cells often appear to be poorly related to values expected from observed radiation response in patients, intensive research on cell viability assays will almost certainly yield more realistic results.     

Lymphocyte subsets in normal bone marrow

Bone marrow aspirates and biopsies from ten normal donors were stained directly with monoclonal antibodies specific for lymphocyte, monocyte, and myeloid antigens, and were analyzed by flow cytometry. To avoid cell loss, lymphocytes were not specifically isolated prior to staining. T cells comprised 46% of aspirate lymphocytes and 22% of biopsy lymphocytes. Further, the Leu-3:Leu-2 ratio of bone marrow T cells was below 1.0. B cells comprised 8% to 11% of bone marrow lymphocytes in both aspirates and biopsies, and there was a substantial percentage of cells in the lymphocyte window that was negative for all B and T cell markers. The lymphocyte window had very little myeloid contamination; however, when the myeloid window was examined, staining was greater than 90%.     

Detection and significance of alpha granule membrane protein 140 expression on platelets collected by apheresis

Activation of platelets may be measured by using the monoclonal antibody S12 to detect alpha granule membrane protein 140 (GMP-140) antigen expressed only on activated platelets. S12 was used to measure activation of apheresis platelet concentrates by flow cytometry. Eleven platelet concentrates obtained by one method and nine obtained by another were analyzed 4 hours after collection. Means +/- 1SD of 25.3 +/- 14.8 percent and 28.9 +/- 11.6 percent, respectively, of platelets were found to be activated (range, 4.8-53.1%). Six of the platelet concentrates obtained by the second method were filtered. There was a drop of 17.8 percent (range, 10-25%) in the mean total number of platelets recovered after filtration, but there was no difference in the proportion of activated platelets measured immediately before and after filtration. The 1-hour posttransfusion platelet count increment was obtained after 12 of these apheresis platelet concentrates were transfused to eight patients who were not refractory from either a clinical or alloimmune standpoint. There was a significant inverse correlation between the platelet count increment and the proportion of activated platelets in the component (p less than 0.05, r = -.58). These data suggest that apheresis platelet concentrates with more activated platelets have a reduced 1-hour recovery. Filtration did not enhance activation or selectively remove activated platelets. Expression of GMP-140 may serve as a useful quality control measurement.