Gender, relationships, and crack cocaine: a content analysis

Past research has indicated gender differences among narcotic users that have implications for the prevention and treatment of substance abuse; however, little is known about these differences among crack cocaine users. The purpose of this secondary analysis was to compare the relational context of male and female crack cocaine use. Data from open-ended, structured interviews with 46 predominantly African-American women (n = 23) and men (n = 23) were compared using manifest content analysis. Women were more likely to begin, use and/or maintain their use of crack in the context of more intimate opposite sex relationships, while men were more likely to begin their use with male friends and associates and to maintain drug use with income from jobs and selling drugs. Overall, relationships (both sexual and familial) were a more prominent aspect of crack use for women while enterpreneurship was more salient for men. These findings suggest the need for gender-sensitive prevention and treatment strategies.

Early embryonic failure associated with uniparental disomy for human chromosome 21

As many as 16% of all recognized pregnancies may be anembryonic, with failure of the embryo at a very early stage of development leaving only the extraembryonic components of the conceptus to proliferate. Studies in the mouse have shown that the maternal and paternal contributions to the genome of the zygote are not functionally equivalent, due to parental genomic imprinting. Uniparental disomy can reveal imprinting effects, as in this phenomenon both members of a chromosome pair are inherited from the same parent. We have carried out a systematic search for uniparental disomy in tissues from 23 cases of early embryonic failure, using variable number tandem repeat (VNTR) analysis and PCR amplification of polymorphic short sequence repeats. Two cases of maternal uniparental heterodisomy for chromosome 21 were identified. One case occurred in conjunction with trisomy for chromosomes 7 and 9, but in the other case maternal uniparental heterodisomy for chromosome 21 was the only chromosomal abnormality found. We therefore postulate that there may be developmentally important genes on human chromosome 21 which are imprinted such that both parental copies are essential for normal embryogenesis.

Linkage analysis of 62 X-chromosomal loci excludes the X chromosome in an Icelandic family showing apparent X-linked recessive inheritance of neural tube defects

We report here the findings of a linkage analysis, involving numerous markers from the human X chromosome, in an attempt to localise a putative gene causing apparent X-linked spina bifida and anencephaly (SBA) in a large Icelandic pedigree. Two-point linkage analysis was performed using markers from 62 informative loci in this family. Although small positive lod scores were found at a number of these loci, none reached the significance level for linkage. Haplotypes were extensively analysed and found to exclude linkage to the X chromosome.

Transposition of IS117, the 2.5 kb Streptomyces coelicolor A3(2) 'minicircle': roles of open reading frames and origin of tandem insertions

IS117 is a 2527 bp transposable element from Streptomyces coelicolor A3(2) with a circular transposition intermediate. Disruption of ORF1 of IS117, presumed to encode a transposase, abolished transposition. Deletion or mutation of ORF2 and ORF3, which overlap each other on opposite strands of IS117, caused a c. 20-fold reduction in integration frequency of the circular form of IS117 into the Streptomyces lividans chromosome or into the preferred chromosomal target site cloned on a plasmid in transformation experiments. In contrast, inactivation of ORF2/3 did not significantly influence transposition of IS117 derivatives from an already integrated state in the chromosome to the preferred target site cloned on a plasmid. ORF2 mutants apparently excised readily from the S. lividans chromosome, whereas excision of integrated wild-type IS117 derivatives to yield the unoccupied site was not detected; presumably, therefore, the circular transposition intermediate normally arises replicatively. Attempts to promote integration of a plasmid carrying the attachment site of IS117 by providing the ORF1 product in trans were unsuccessful. Most transformation of S. lividans with circular IS117 derivatives yielded tandem chromosomal insertions, which arose by co-transformation rather than dimerization of a monomeric insert. Typically, two to three transforming elements gave a transformed strain, suggesting a local concentration of transposase as a limit on integration.

Expression of human chorionic gonadotrophin alpha and beta subunits is depressed in trophoblast from pregnancies with early embryonic failure

The expression of the placental proteins human chorionic gonadotrophin alpha (HCG alpha), beta (HCG beta) and human placental lactogen (HPL) was examined in trophoblast from human normal pregnancy and early embryonic failure (EEF) using Northern blot analysis. Trophoblast from EEF expressed significantly depressed levels of HCG alpha (P < 0.05) and HCG beta (P < 0.01) when compared to normal pregnancy. Levels of expression of HPL in EEF were not significantly different to those from normal pregnancy. The gestational ages of the two groups were not significantly different. Immunocytochemistry on paraffin-fixed tissue sections supported these data and showed that mRNA levels reflected protein production of HCG within the tissue. It appears from these data that the depressed level of HCG found in the serum of women with early pregnancy failure is not solely a consequence of diminished placentation in these pregnancies, or placental necrosis, but that the genes of the alpha and beta HCG subunits are down-regulated. This study further suggests that there are two subsets of women with early pregnancy failure; those with apparently normal levels of placental proteins, and those with severely depressed levels. It would seem likely that these two groups have different aetiologies.

Toward culturally sensitive research in a multicultural society

Applying research methods and techniques developed in a dominant culture to other cultures can threaten the validity and generalizability of research conducted with other cultures. Guidelines are proposed for increasing the cultural sensitivity of research, and a case example is discussed.

Changes in expression of the cyclooxygenase gene in human fetal membranes and placenta with labor

OBJECTIVE

Our objective was to examine the expression of the gene coding for cyclooxygenase, the central enzyme in prostaglandin synthesis, in human placenta and fetal membranes during pregnancy and before and after labor at term.

STUDY DESIGN

Expression of the gene for cyclooxygenase was examined with Northern hybridization to ribonucleic acid from human placenta throughout pregnancy and human amnion and chorion decidua in the late third trimester.

RESULTS

Expression was undetectable in trophoblast during the first and second trimesters. Expression in amnion and trophoblast increased 3.5- and 2.5-fold, respectively, in association with labor.

CONCLUSIONS

Our results suggest that the increase in prostaglandin synthesis within the uterus that is seen with the onset of labor is associated with an increase in the expression of the gene cyclooxygenase.

Trophoblast from anembryonic pregnancy has both a maternal and a paternal contribution to its genome

In a series of 14 anembryonic pregnancies, deoxyribonucleic acid from trophoblast was examined with locus-specific minisatellite probes. It was found in each case that trophoblast from anembryonic pregnancy has both a maternal and a paternal contribution to its genome. This means that although anembryonic pregnancy shares characteristics with complete hydatidiform mole and androgenetic development in the mouse in that there is no embryo, it does not arise by the same genetic process. Of three anembryonic pregnancies that were successfully karyotyped, two had normal female 46,XX chromosome constitutions and one had an abnormal 47,XX + 16 complement. The sex of the trophoblast in each anembryonic pregnancy was determined with a deoxyribonucleic acid probe with Y-specific bands. A male-to-female ratio of 6:8 was found, which is not significantly different from normal.

Comparison of the effects of FK-506, cyclosporin A and rapamycin on IL-2 production

The immunosuppressive compounds FK-506, cyclosporin A (CsA) and rapamycin inhibit both the human and mouse mixed lymphocyte reactions (MLR) with IC50s of 2-5 x 10(-10) M for FK-506 and rapamycin and 10(-8) M for CsA. FK-506 and CsA were also potent inhibitors of A23187/PMA-stimulated IL-2 production by Jurkat and HuT-78 cells but had no effect on the response of mouse CTLL cells to IL-2. IC50 values for inhibition of IL-2 production closely matched those for inhibition of the MLR and both drugs were active only during the first 4-6 hr following stimulation. In contrast, rapamycin was a poor inhibitor of IL-2 production, although it inhibited cellular responses to IL-2. The IC50 values for these two activities indicated that neither alone accounted for rapamycin inhibition of the MLR. FK-506 and CsA affected IL-2 gene transcription in Jurkat cells by the same mechanism. Both inhibited the appearance of the transcription factor, NFAT, whereas rapamycin did not. The appearance of another transcription factor, NFK beta, was unaffected by all three drugs. The effects of FK-506 and CsA on IL-2 gene expression, therefore, are similar even though the two drugs act through distinct cytosolic receptors.

Two RFLPs at the D12S51 locus

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