Multicenter evaluation of the performance and clinical utility in longitudinal monitoring of the Bayer Immuno 1 complexed PSA assay.

We conducted a multicenter evaluation of the analytical and clinical performance of the automated Bayer Immuno 1 complexed PSA (cPSA) assay, and compared assay performance to the Bayer Immuno 1 PSA assay. We sought to determine whether measurements of cPSA could be of clinical utility in the management of patients with prostate cancer. Results of the 10-day imprecision across three evaluation sites produced total CV < 2.50% and an analytical sensitivity of 0.02 microgram/L. There was an increased trend in clinical sensitivity for prostate cancer with increasing stage of disease (71-86%). Clinical specificity for patients with benign urogenital disease was 74.8%, and for other nonprostate diseases ranged from 91.1-100%. Retrospective serial monitoring of 155 patients with prostate cancer demonstrated concordance of cPSA measurements to clinical status for 97% of the patients analyzed. Results from the clinical studies using the Bayer Immuno 1 cPSA assay were comparable to results obtained with the Bayer Immuno 1 PSA assay. The Bayer Immuno 1 cPSA assay demonstrates analytical performance and clinical effectiveness in the management of prostate cancer patients during the course of disease and therapy.     

Patterns of meiotic double-strand breakage on native and artificial yeast chromosomes

The preferred positions for meiotic double-strand breakage were mapped on Saccharomyces cerevisiae chromosomes I and VI, and on a number of yeast artificial chromosomes carrying human DNA inserts. Each chromosome had strong and weak double-strand break (DSB) sites. On average one DSB-prone region was detected by pulsed-field gel electrophoresis per 25 kb of DNA, but each chromosome had a unique distribution of DSB sites. There were no preferred meiotic DSB sites near the telomeres. DSB-prone regions were associated with all of the known ”hot spots” for meiotic recombination on chromosomes I, III and VI. Received: 19 March 1996; in revised form: 26 July 1996 / Accepted: 18 August 1996     

Chromatin structure visualization by immunoelectron microscopy

Antibodies elicited in rabbits by chromatin and by purified histone H2B have been used to study the structure of chromatin by immunoelectron microscopy. Chromatin spread on grids reveals a structure of closely packed spherical particles with an average diameter of 104 Å, arranged either in clusters or in linear arrays of beads, some of which have a supercoil-like arrangement. No DNA strings connecting the beads could be observed. Upon antibody binding, the diameter of the particles increases up to 300 Å. This size is compatible with a model where one layer of gamma globulin molecules 110 Å long encircles a sphere of chromatin 100 Å in diameter. The presence of rabbit gamma globulins on the enlarged beads has been verified by the addition of ferritin-labeled goat anti-rabbit gamma globulins. Anti-chromatin sera which react with nonhistone proteins but not with free histones or DNA react with more than 95% of the beads; this suggests that most of the beads contain nonhistone proteins. Since the number of nonhistone proteins is large, it is improbable that each sphere contains a full complement of these proteins. We therefore suggest that the various chromatin spheres contain different types of nonhistone proteins. About 90% of the chromatin spheres reacted with antibodies to histone H2B, suggesting that most of the chromatin beads contain this type of histone.     

Revision of the bulbous Iridaceae of North America

The native bulbous Iridaceae of North America excluding Mexico comprise seven species in four genera. The type species ofAlophia Herb. (1836) is shown to belong toEustylis Engelm. & Gray (1836), hence the latter genus is reduced to synonymy. The well known genusAlophia (sensu auct. non Herb.) (Herbertia Sweet) now takes the nameTrifurcia. As a result of the new interpretation ofAlophia, new combinations are made for the North American and Latin American species ofTrifurcia andAlophia. New chromosome counts are given forNemastylis floridana (2n = 56) andTrifurcia lahue (2n = 56).     

Exposure of histone antigenic determinants in chromatin.

The exposure of antigenic determinants of histones present in "native" chromatin was studied by: (1) testing their ability to elicit anti-histone antibodies and (2) measuring their ability to interact with anti-histone sera. To this end, antisera specific to purified histone fractions and to purified rat liver chromatin were elicited in rabbits. The anti-chromatin sera did not react with pure histone fractions and pure histone fractions F2b, F3, F2a1, and F2a2 failed to inhibit the complement fixation resulting from the binding of anti-chromatin to chromatin. These results suggest that in native chromatin, determinants in these histones are not immunogenic. Histone F1, however, inhibited the reaction between chromatin and anti-chromatin. Antisera elicited by histone fractions reacted weakly with "native" chromatin. The maximal complement fixations (obtained with 5-10 mug of chromatin DNA) were as follows: 60% with anti-F2b, 20% with anti-F1 and anti-F3, and less than 5% with either anti-F2a1 or anti-F2a2. Studies of the interaction between anti-histone antibodies and chromatin in which chromatin was used as an immunoadsorbent indicated that antibodies against different histones were adsorbed to a different degree by the same amount of chromatin. Differences in the immunoadsorbing capacity between sonicated and nonsonicated chromatin were found. Quantitative adsorbtion studies revealed that in the "native" chromatin structure, antigenic determinants of F1 and F2b were more available to interact with homologous antibody than those of F3 and F2a1 and that determinants in F2a2 were the least available. It could be calculated that the "equivalent antigenicity" of the histones in chromatin was 9.6% for F1, 3.2% for F2b, and 0.90% for F3 and F2a1. Upon sonication these values did not change for F1 but increased two-, three-, and fourfold for F2b, F3, and F2a1, respectively. Digestion of chromatin with trypsin totally abolished the ability of chromatin to adsorb anti-histone antibodies.     

Pediatric Invasive Pneumococcal Disease Caused by Vaccine Serotypes following the Introduction of Conjugate Vaccination in Denmark

A seven-valent pneumococcal conjugate vaccine (PCV7) was introduced in the Danish childhood immunization program (2+1 schedule) in October 2007, followed by PCV13 starting from April 2010. The nationwide incidence of IPD among children younger than 5 years nearly halved after the introduction of PCV7 in the program, mainly due to a decline in IPD caused by PCV7-serotypes. We report the results from a nationwide population-based cohort study of laboratory confirmed IPD cases in children younger than 5 years during October 1, 2007 to December 31, 2010 and describe the characteristics of children suspected to present with a vaccine failure. The period between April 19 and December 31, 2010 was considered a PCV7/PCV13 transitional period, where both vaccines were offered. We identified 45 episodes of IPD caused by a PCV7 serotype (23% of the total number) and 105 (55%) caused by one of the 6 additional serotypes in PCV13. Ten children had received at least one PCV7 dose before the onset of IPD caused by a PCV7 serotype. Seven children were considered to be incompletely vaccinated before IPD, but only three cases fulfilled the criteria of vaccine failure (caused by serotypes 14, 19F and 23F). One case of vaccine failure was observed in a severely immunosuppressed child following three PCV7 doses, and two cases were observed in immunocompetent children following two infant doses before they were eligible for their booster. None of the IPD cases caused by the additional PCV13 serotypes had been vaccinated by PCV13 and there were therefore no PCV13-vaccine failures in the first 8-months after PCV13 introduction in Denmark.     

Prevalence and Correlates of HIV Infection among Street Boys in Kisumu,Kenya

Introduction

Despite their perceived vulnerability to HIV, East African street youth have been neglected in HIV prevention research. We examined HIV seroprevalence and correlates of HIV infection in a sample of male street youth in Kisumu, Kenya.

Methods

We enrolled a street-recruited sample of 13–21 year old street youth. Participants completed a survey followed by voluntary HIV counseling and testing. Survey items included demographics, homelessness history, survival activities, sexual behavior and substance use. We examined the relationship between predictor variables, markers of coercion and marginalization and HIV.

Results

The sample included 296 males. Survival activities included garbage picking (55%), helping market vendors (55%), begging (17%), and working as porters (46%) or domestic workers (4%). Forty-nine percent of participants reported at least weekly use of alcohol and 32% marijuana. Forty-six percent of participants reported lifetime inhalation of glue and 8% fuel. Seventy-nine percent of participants reported lifetime vaginal sex, 6% reported lifetime insertive anal sex and 8% reported lifetime receptive anal sex. Twelve (4.1%; 95% CI: 2.3–7.0) participants tested positive for HIV. Of those, all had been on the street for at least one year and all had engaged in vaginal sex. Occupations placing youth at particular risk of coercion by adults, including helping market vendors (prevalence ratio (PR) = 8.8; 95% CI: 1.2–67.5) and working as domestic workers (PR = 4.6; 95% CI: 1.1–19.0), were associated with HIV infection. Both insertive anal sex (PR = 10.2; 95% CI: 3.6–29.4) and receptive anal sex (PR = 3.9; 95% CI: 1.1–13.4) were associated with HIV infection. Drug use, begging, and garbage picking were not associated with HIV infection.

Conclusions

Although HIV prevalence in our sample of street youth is comparable to that of similarly-aged male youth in Nyanza Province, our findings highlight behavioral factors associated with HIV infection that offer opportunities for targeted prevention among street youth in East Africa.     

Mammalian meiosis involves DNA double-strand breaks with 3′ overhangs

Meiotic recombination in yeast is initiated at DNA double-strand breaks (DSBs), processed into 3′ single-strand overhangs that are active in homology search, repair and formation of recombinant molecules. Are 3′ overhangs recombination intermediaries in mouse germ cells too? To answer this question we developed a novel approach based on the properties of the Klenow enzyme. We carried out two different, successive in situ Klenow enzyme-based reactions on sectioned preparations of testicular tubules. Signals showing 3′ overhangs were observed during wild-type mouse spermatogenesis, but not in Spo11 ^?/? males, which lack meiotic DSBs. In Atm ^?/? mice, abundant positively stained spermatocytes were present, indicating an accumulation of non-repaired DSBs, suggesting the involvement of ATM in repair of meiotic DSBs. Thus the processing of DSBs into 3′ overhangs is common to meiotic cells in mammals and yeast, and probably in all eukaryotes.     

Explaining disparities in species richness between Mediterranean floristic regions: a case study in Gladiolus (Iridaceae)

Aim The causes of geographical variation in species richness in clades that do not follow the latitudinal diversity gradient have rarely been investigated. Here, we examine spatial asymmetries of diversity in Gladiolus (Iridaceae), a large genus (> 260 species) that is present in two mediterranean climate biomes: the Cape of southern Africa (106 species) and the Mediterranean Basin (7 species). Despite convergence of climatic conditions between the two regions, the species density of Gladiolus is over one order of magnitude higher in the Cape than in the Mediterranean Basin. We investigate whether the diversity disparities observed in the genus are better explained by recent colonization of species‐poor areas (temporal hypothesis) or by differential rates of diversification (evolutionary hypothesis). Location Africa, Madagascar and Eurasia Methods We employ a recently developed Bayesian method for the estimation of diversification rates and a biogeographical optimization approach within a phylogenetic framework. Results In Gladiolus, the ‘diversity anomaly’ between the two Mediterranean climate regions cannot be explained solely by the time available for speciation in the Cape, but is also due to locally reduced rates of diversification in the Mediterranean Basin. Furthermore, high overall diversity in southern Africa stems from an ancient origin in the Cape allied with high rates of diversification in the summer‐rainfall region of the subcontinent. Main conclusions Both evolutionary and temporal hypotheses must be taken into account in order to explain the diversity anomaly between the Mediterranean Basin and the Cape. Our results suggest that regions at comparable latitudes and/or with similar climate may not converge in diversity levels due to heterogeneity of diversification rates and contrasting biogeographical histories.