Genotyping of KEL1 and KEL2 of the human Kell blood group system by the polymerase chain reaction with sequence-specific primers

BACKGROUND: Kell is a major antigenic system in human red cells, with more than 20 identified antigens. KEL1 and KEL2 are two opposing low- and high-frequency alleles. Immunization to KEL1 is clinically significant, because anti-KEL1 can cause severe reactions to transfusion of incompatible blood, as well as hemolytic disease of the newborn. At the nucleotide level, the difference between the KEL2 and KEL1 alleles is a single-base change within exon 6 that results in the substitution of methionine (ATG) for threonine (ACG) at position 193. STUDY DESIGN AND METHODS: An assay using polymerase chain reaction and sequence-specific primers to genotype for the KEL1 and KEL2 alleles has been developed. It uses two allele-specific forward primers for either KEL1 or KEL2 and a single reverse-consensus primer. RESULTS: A validation study of 42 serologically typed samples (5 KEL:1,-2 [K+k-]; 23 KEL:1,2 [K+k+]; and 14 KEL:-1,2 [K-k+]) was performed. A concordance rate of 100 percent (42/42 samples) was observed between polymerase chain reaction with sequence-specific primers and serologic typing. CONCLUSION: This rapid, nonradioactive, Kell system genotyping assay does not require the additional steps of probe hybridization or restriction enzyme digestion. This application of polymerase chain reaction with sequence-specific primers should prove particularly useful in Kell system genotyping of amniotic cells to identify pregnancies at risk for hemolytic disease of the newborn.     

Involvement of polyamines in selenomethionine induced apoptosis and mitotic alterations in human tumor cells

The efficacy of dietary selenium supplementation is currently being evaluated in intervention trials. However, the biological mechanisms underlying the cancer chemopreventive effects of selenium supplementation have yet to be elucidated. Selenium metabolism and polyamine biosynthesis are linked in their common requirement for S- adenosylmethionine. Selenomethionine was the predominant form of selenium in the dietary supplement, therefore we evaluated the anti- tumorigenic effects of selenomethionine. We found that selenomethionine inhibited tumor growth (both in A549 lung and HT29 colon cancer cells) in a dose-dependent manner. At 24 and 72 h, polyamine content of A549 and HT29 cancer cell lines was decreased at doses that inhibited 50% of normal growth. Selenomethionine treatment induced apoptosis in both cancer cell lines. Exogenous spermine administration, which replenishes intracellular polyamine levels, prevented selenomethionine induced apoptosis. Selenomethionine administration to the cancer cell lines increased the number of cells in metaphase. This cell cycle effect appeared to be reversed with the co-administration of selenomethionine and spermine. These data suggested that at least part of the anti- carcinogenic effects of selenium supplementation might be due to a depletion in polyamine levels. This depletion of polyamines leads to an induction in apoptosis and perturbations in the cell cycle.      

Hepatitis B among homeless and other impoverished US military veterans in residential care in Los Angeles

Findings are presented for a cross-sectional study of serological markers of hepatitis B virus (HBV) infection in an underserved population-impoverished veterans of the US armed forces in a Veterans Administration (VA) residential program in the US. We examine the demographic, background, and risk factors associated with HBV infection in this high-risk population. This paper presents a secondary analysis of cross-sectional survey and clinical data for 370 male veterans who were residents of a domiciliary care program for homeless veterans in Los Angeles, using chi(2), Fisher's Exact, and logistic regression analysis. About one-third (30.8%) of the sample tested positive for current or past HBV infection (ie, seropositive for either the HBV core antibody or surface antigen). After multivariate analysis, rates of HBV were significantly higher among veterans who were older, non-white, or who had a history of regular heroin use (a proxy measure for injection drug use), drug overdose, or drug detoxification treatment. The rate of current or past HBV infection among veterans in this sample (30.8%) was high compared to an estimated 5% to 8% of the general US population. Also, 3% of the sample were currently infected with HBV. Strategies for intervention include broader screening, immunization, and treatment interventions with this high-risk group.