Exposure to PCB 77 affects partner preference but not sexual behavior in the female rat

In rats, exposure to the polychlorinated biphenyl congener 3, 4, 3′, 4′-tetrachlorobiphenyl (PCB 77) affects the brain and behavior of the offspring as well as the maternal behavior of the dams. In the present study, a cross-fostering design was used to examine the effects of pre- and/or postnatal exposure to PCB 77 on sexual behavior and partner preference in female rats, and to determine the role of altered maternal behavior in the mediation of these effects. Pregnant rats were treated with oil or PCB dissolved in oil (2 mg/kg b.w.) on gestation days 6-18 and then given pups that had been exposed to either the oil vehicle or PCB during gestation. As adults, the female offspring were tested for partner preference (that is, whether they preferred to spend time with a sexually receptive female or a sexually active male) and sexual behavior. None of the treatments affected female sexual behavior. However, both double exposure and postnatal exposure diminished the animals' preference for a male over a female stimulus, but partner preference was not affected by prenatal exposure alone. There were no significant correlations between the changes in partner preferences due to PCB exposure and the amount of maternal grooming and licking received by the treated litters. Thus, female partner preference is affected by early PCB exposure, and the effects depend upon whether the exposure is in utero or via lactation and may be independent of any effects of the PCB on maternal care.     

Identification of clinical coryneform bacterial isolates: comparison of biochemical methods and sequence analysis of 16S rRNA and rpoB genes

We compared the relative levels of effectiveness of three commercial identification kits and three nucleic acid amplification tests for the identification of coryneform bacteria by testing 50 diverse isolates, including 12 well-characterized control strains and 38 organisms obtained from pediatric oncology patients at our institution. Between 33.3 and 75.0% of control strains were correctly identified to the species level by phenotypic systems or nucleic acid amplification assays. The most sensitive tests were the API Coryne system and amplification and sequencing of the 16S rRNA gene using primers optimized for coryneform bacteria, which correctly identified 9 of 12 control isolates to the species level, and all strains with a high-confidence call were correctly identified. Organisms not correctly identified were species not included in the test kit databases or not producing a pattern of reactions included in kit databases or which could not be differentiated among several genospecies based on reaction patterns. Nucleic acid amplification assays had limited abilities to identify some bacteria to the species level, and comparison of sequence homologies was complicated by the inclusion of allele sequences obtained from uncultivated and uncharacterized strains in databases. The utility of rpoB genotyping was limited by the small number of representative gene sequences that are currently available for comparison. The correlation between identifications produced by different classification systems was poor, particularly for clinical isolates.     

Should genetic testing for BRCA1/2 be permitted for minors? Opinions of BRCA mutation carriers and their adult offspring

Although professional guidelines recommend against testing minors for adult-onset genetic conditions, the genetic testing of minors for BRCA1/2 alterations has been debated in the literature. To better understand the opinions of BRCA mutation carriers regarding the genetic testing of minors and the cognitive and affective processes underlying these opinions, we interviewed BRCA mutation carriers and their adult offspring who had learned of their parent's BRCA mutation. Semi-structured interviews were conducted with 53 parents and 22 offspring. In response to a closed-ended question, 52% (n = 39) of participants were opposed to the testing of minors. Responses to an open-ended question indicate that many participants (24%, n = 18) feel that testing could be permitted for some minor offspring. Psychological risks and the insufficient maturity of minors were frequent concerns of participants opposed to testing minors. The potential to impact health behaviors was frequently cited as a reason to support the genetic testing of minors. These preliminary results suggest that many BRCA mutation carriers and their adult offspring have concerns about, or are opposed to the genetic testing of minors. However, a significant minority in our study would support testing minors. Greater support for testing among offspring could indicate increasing requests for early genetic diagnosis. Further research is necessary to explore the risks and benefits of providing genetic testing to minors for adult-onset hereditary cancer syndromes in order to inform clinical practice and public policy and to ensure optimal psychosocial and medical outcomes for all members in families at risk for genetically determined disease.     

December 1998--16 year old female with headaches, lethargy and a sellar/suprasellar mass

A 16 year female with a history of developmental delay and shunted hydrocephalus presented with two months of progressive headaches, lethargy and visual disturbances. An MRI of the brain revealed a sellar and suprasellar cystic mass which was absent on a previous MRI six years earlier. The pre-operative clinical diagnosis was pituitary adenoma vs. craniopharyngioma. Histologically, the fibrous wall of the ciliated epithelial-lined cyst was thickened by non-caseating granulomatous inflammation, hemorrhage, hemosiderin, and cholesterol clefts, consistent with cyst rupture. Rathke's cleft cysts are uncommon symptomatic lesions in young people, and must be distinguished from craniopharyngioma.     

Characterisation of a subtype of colorectal cancer combining features of the suppressor and mild mutator pathways

BACKGROUND: 10% of sporadic colorectal cancers are characterised by a low level of microsatellite instability (MSI-L). These are not thought to differ substantially from microsatelite-stable (MSS) cancers, but MSI-L and MSS cancers are distinguished clinicopathologically and in their spectrum of genetic alterations from cancers showing high level microsatellite instability (MSI-H). AIMS: To study the distribution of molecular alterations in a series of colorectal cancers stratified by DNA microsatellite instability. METHODS: A subset of an unselected series of colorectal cancers was grouped by the finding of DNA MSI at 0 loci (MSS) (n = 51), 1-2 loci (MSI-L) (n = 38) and 3-6 loci (MSI-H) (n = 25). The frequency of K-ras mutation, loss of heterozygosity (LOH) at 5q, 17p and 18q, and patterns of p53 and beta catenin immunohistochemistry was determined in the three groups. RESULTS: MSI-H cancers had a low frequency of K-ras mutation (7%), LOH on chromosomes 5q (0%), 17p (0%) and 18q (12.5%), and a normal pattern of immunostaining for p53 and beta catenin. MSI-L cancers differed from MSS cancers in terms of a higher frequency of K-ras mutation (54% v 27%) (p = 0.01) and lower frequency of 5q LOH (23% v 48%) (p = 0.047). Whereas aberrant beta catenin expression and 5q LOH were concordant (both present or both absent) in 57% of MSS cancers, concordance was observed in only 20% of MSI-L cancers (p = 0.01). CONCLUSIONS: MSI-L colorectal cancers are distinct from both MSI-H and MSS cancers. This subset combines features of the suppressor and mutator pathways, may be more dependent on K-ras than on the APC gene in the early stages of neoplastic evolution, and a proportion may be related histogenetically to the serrated (hyperplastic) polyp.     

Instillation of allogeneic lung antigen-presenting cells deficient in expression of major histocompatibility complex class I or II antigens have differential effects on local cellular and humoral immunity and on pathology in recipient murine lungs

Recognition of allogeneic major histocompatibility complex (MHC) molecules expressed on donor lung antigen-presenting cells (APCs) by host T lymphocytes is believed to stimulate lung allograft rejection. However, the specific roles of donor MHC molecules in the rejection response is unknown. We report a murine model in which instilling allogeneic lung APCs into recipient lungs induces pathology analogous to acute rejection, and the production of interferon (IFN)-gamma, immunoglobulin (Ig) G2a, and alloantibodies in recipient lungs. Using allogeneic lung APCs (C57BL/6, I-a(b), H-2(b)) deficient in MHC class I, II, or both for instillation into lungs of BALB/c mice (I-a(d), H-2(d)), the purpose of the current study was to determine the specific roles of donor MHC molecules in stimulating local alloimmune responses. The data show that MHC class I or II on donor APCs induced IFN-gamma and IgG2a synthesis locally, though less than that induced by wild-type cells. Both MHC class I and II were required to induce alloantibody production. Instillation of wild-type or class I- or class II-deficient APCs induced comparable pathologic lesions in recipient lungs, and more severe than that induced by MHC-deficient cells. These data show that donor MHC class I and II molecules have differential effects in the stimulation of local alloimmune responses.     

Comparison of physical and emotional side effects of progesterone or medroxyprogesterone in early postmenopausal women

OBJECTIVE: To compare the mood and somatic effects during the initial 2 months of medroxyprogesterone acetate (MPA) or progesterone combined with conjugated equine estrogen (CEE) in early postmenopausal women. DESIGN: Twenty-three nondepressed, early postmenopausal women (average age, 52.5 years) completed a 91-day, single-blind pilot study with the following sequence of treatments: 1 week of no substance; 2 weeks of placebo; 2 weeks of progestogen only; 1 week of placebo; and 2 months of "standard hormone replacement therapy cycles," which consisted of (in order) 2 weeks of 0.625 mg CEE, 2 weeks of CEE plus progestogen, 2 weeks of CEE, and 2 weeks of CEE plus progestogen. Ten women who completed the study received MPA (5 mg/day) as their progestogen, and 13 who completed the study received micronized, oil-suspended progesterone (200 mg/day) as their progestogen. All participants made daily assessments of mood using the Profile of Mood States and daily recordings of somatic symptoms. All subjects had plasma follicle-stimulating hormone of greater than 35 IU/L and had not had spontaneous vaginal bleeding for more than 1 year. RESULTS: None of the hormone treatments had a detectable effect on mood. MPA users reported more vaginal bleeding and breast tenderness than progesterone users. CONCLUSIONS: In contrast with the widely held belief among psychiatrists that progesterone depresses mood, neither of the progestogens we used in normal, nondepressed and nonanxious women showed this effect. Absence of an effect on mood was also found when the results of the two progestogens were combined. The lesser side effects of the micronized progesterone-containing regimen suggest that some women may prefer it to an MPA-containing regimen.