Synthesis and thermodynamic studies of two new polymers carrying amido and amino groups in the side chains

Two linear vinyl polymers carrying amido and primary amino groups in the side chains were synthesized and characterized. Their behaviour in aqueous solution was investigated by potentiometric, viscometric and calorimetric techniques. In both cases, the basicity constants show a linear dependence on the degree of protonation α, while the enthalpy values of protonation do not. The thermodynamic results demonstrate the important role of hydrophobic interactions on the protonation process.     

Immunoblotting of Creutzfeldt-Jakob disease prion proteins: host species-specific epitopes

Creutzfeldt-Jakob disease (CJD) is a rare dementia that is generally found in older people and is caused by unusual infectious pathogens or prions. Using rabbit antisera raised against hamster scrapie prion proteins (HaPrPSc), we identified by immunoblotting human CJD prion proteins (HuPrPCJD) in the brains of 14 patients dying of CJD. Extracts from 6 of the patients were transmitted to mice after prolonged incubation. The rabbit antisera raised against HaPrPSc also reacted with the mouse CJD prion proteins (MoPrPCJD) found in the brains of these experimentally infected mice. When mice were immunized with HuPrPCJD, they produced antibodies that reacted with HuPrPCJD but not with MoPrPCJD. Mice immunized with MoPrPCJD produced antibodies to neither murine nor human prion proteins. Our results provide evidence for host species-specific epitopes on prion proteins. The existence of such epitopes is consistent with the apparent lack of an immune response during prion infections and the finding that prion protein molecules are encoded by host genes.     

Expansions and contractions of the FMR1 CGG repeat in 5,508 transmissions of normal,intermediate, and premutation alleles

Instability of the FMR1 repeat, commonly observed in transmissions of premutation alleles (55–200 repeats), is influenced by the size of the repeat, its internal structure and the sex of the transmitting parent. We assessed these three factors in unstable transmissions of 14/3,335 normal (~5 to 44 repeats), 54/293 intermediate (45–54 repeats), and 1561/1,880 premutation alleles. While most unstable transmissions led to expansions, contractions to smaller repeats were observed in all size classes. For normal alleles, instability was more frequent in paternal transmissions and in alleles with long 3′ uninterrupted repeat lengths. For premutation alleles, contractions also occurred more often in paternal than maternal transmissions and the frequency of paternal contractions increased linearly with repeat size. All paternal premutation allele contractions were transmitted as premutation alleles, but maternal premutation allele contractions were transmitted as premutation, intermediate, or normal alleles. The eight losses of AGG interruptions in the FMR1 repeat occurred exclusively in contractions of maternal premutation alleles. We propose a refined model of FMR1 repeat progression from normal to premutation size and suggest that most normal alleles without AGG interruptions are derived from contractions of maternal premutation alleles.     

Primary Immunodeficiency Syndrome in Spain: First Report of the National Registry in Children and Adults

The Spanish Registry for Primary Immunodeficiency Diseases (REDIP) was organized in 1993. One thousand sixty-nine cases of primary immunodeficiency diseases (PID) were registered in patients diagnosed between January 1980 and December 1995. PID diagnosis was made according to the World Health Organization criteria. The most frequent disorders were IgA deficiency (n = 394) and common variable immunodeficiency (n = 213), followed by severe combined immunodeficiency (n = 61), C1 inhibitor deficiency (n = 52), X-Iinked agammaglobulinemia (n = 49), IgG subclass deficiency (n = 48), and chronic granulomatous disease (n = 32). A comparative study between REDIP and data recently obtained from the European registry (ESID Report, 1995) revealed important differences between phagocytic disorders and complement deficiencies reported in both registries, 4.9 vs 8.7 and 6.0 vs 3.6, while percentages of predominantly antibody deficiencies and T cell and combined deficiencies concurred with those reported in the European registry, 69.3 vs 64.7 and 14.7 vs 20.2, respectively. The heterogeneous nature of the geographical distribution of cases submitted may indicate underdiagnosis of PID in some country areas; surprisingly, the interval between the onset of clinical symptoms and diagnosis was significant, even in immunodeficiency diseases, such as IgA deficiency, which are easy to diagnose.     

Laboratory toxicology of six forestry insecticides to four species of bee (hymenoptera: Apoidea)

Laboratory dose-response studies were conducted with four species of adult bees, Apis mellifera (workers), Andrena erythronii (females), Megachile rotundata (females), and Bombus terricola (workers), using six insecticides, permethrin, mexacarbate, aminocarb, fenitrothion, carbaryl, and trichlorfon. All insecticides were applied topically to the thorax of the bees as technical grade in an acetone carrier. Mortality was accumulated over 48 h, and probit analyses were conducted separately on data sets expressed in units of gAI (active ingredient)/g body weight and of gAI/bee. LD₅₀ values with 95% confidence limits and slopes with standard errors are provided for each bee/insecticide combination in each data set. Relative toxicities, relative susceptibilities, and fresh body weights are also provided. The analysis in units of gAI/g body weight indicated that the insecticides were typically ranked in order of decreasing toxicity—permethrin, mexacarbate, aminocarb, fenitrothion, carbaryl, and trichlorfon. Likewise, the bees ranked from the most to least susceptible in the order of A. mellifera, A. erythronii, M. rotundata and B. terricola. Trends within the data set for units of gAI/bee were less consistent. These data are discussed and compared with other published data on the toxicology of insecticides to bees and from the perspective of risk assessment.     

Circular DNA resulting from recombination between V-(D)-J joining signals and switch repetitive sequences in mouse thymocytes

During the course of analyzing circular DNA in mouse thymocytes, novel recombinants were identified with immunoglobulin heavy chain joining gene and switch region probes. These circles represent excision products of recombination between the heptamer-nonamer motif for V-(D)-J joining and a repetitive sequence for class switching. The molecular mechanisms that generate "hybrid circles" are discussed.