Serum osteoprotegerin levels and mammographic density among high-risk women

Purpose

Mammographic density is a risk factor for breast cancer but the mechanism behind this association is unclear. The receptor activator of nuclear factor κB (RANK)/RANK ligand (RANKL) pathway has been implicated in the development of breast cancer. Given the role of RANK signaling in mammary epithelial cell proliferation, we hypothesized this pathway may also be associated with mammographic density. Osteoprotegerin (OPG), a decoy receptor for RANKL, is known to inhibit RANK signaling. Thus, it is of interest to evaluate whether OPG levels modify breast cancer risk through mammographic density.

Methods

We quantified serum OPG levels in 57 premenopausal and 43 postmenopausal women using an enzyme-linked immunosorbent assay (ELISA). Cumulus was used to measure percent density, dense area, and non-dense area for each mammographic image. Subjects were classified into high versus low OPG levels based on the median serum OPG level in the entire cohort (115.1 pg/mL). Multivariate models were used to assess the relationship between serum OPG levels and the measures of mammographic density.

Results

Serum OPG levels were not associated with mammographic density among premenopausal women (P ≥ 0.42). Among postmenopausal women, those with low serum OPG levels had higher mean percent mammographic density (20.9% vs. 13.7%; P = 0.04) and mean dense area (23.4 cm² vs. 15.2 cm²; P = 0.02) compared to those with high serum OPG levels after covariate adjustment.

Conclusions

These findings suggest that low OPG levels may be associated with high mammographic density, particularly in postmenopausal women. Targeting RANK signaling may represent a plausible, non-surgical prevention option for high-risk women with high mammographic density, especially those with low circulating OPG levels.

     

Functional human CFTR produced by stable Chinese hamster ovary cell lines derived using yeast artificial chromosomes

The cystic fibrosis transmembrane conductance regulator gene (CFTR) encodes a transmembrane protein (CFTR) which functions in part as a cyclic adenosine monophosphate (cAMP)-regulated chloride channel. CFTR expression is controlled temporally and cell specifically by mechanisms that are poorly understood. Insight into CFTR regulation could be facilitated by the successful introduction of the entire 230 kb human CFTR and adjacent sequences into mammalian cells. To this end, we have introduced two different CFTR-containing yeast artificial chromosomes (YACs) (320 and 620 kb) into Chinese hamster ovary-K1 (CHO) cells. Clonal cell lines containing human CFTR were identified by PCR, and the genetic and functional analyses of one clone containing each YAC are described. Integration of the human CFTR-containing YACs into the CHO genome at a unique site in each cell line was demonstrated by fluorescence in situ hybridization (FISH). Southern blot analysis suggested that on the order of one copy of human CFTR was integrated per CHO cell genome. Fiber-FISH and restriction analysis suggested that CFTR remained grossly intact. Northern analysis showed full-length, human CFTR mRNA. Immunoprecipitation followed by phosphorylation with protein kinase demonstrated mature, glycosylated CFTR. Finally, chloride secretion in response to cAMP indicated the functional nature of the human CFTR. This study provides several novel results including: (i) functional human CFTR can be expressed from these YACs; (ii) CHO cells are a permissive environment for expression of human CFTR; (iii) the level of human CFTR expression in CHO cells is unexpectedly high given the lack of endogenous CFTR production; and (iv) the suggestion by Fiber-FISH of CFTR integrity correlates with functional gene expression. These YACs and the cell lines derived from them should be useful tools for the study of CFTR expression.      

The commissuro-mamillary plane in MRI of the brain (preliminary communication)

Summary MRI sections of the brain in the coronal plane through the line joining the anterior commissure and the mamillary bodies display the constituent parts of the basal forebrain. The visualisation of the septal nuclei and the anterior columns of the fornix show the importance of this plane in the study of behaviour disorders and amnesic syndromes.This work was carried out under CNAM/INSERM contract N^o 86 3 36E     

Quantitation of anti-NP (4-hydroxy-3-nitrophenyl)-acetyl idiotype expression on spleen and thymus cells

Direct binding of ¹²⁵I-labeled rabbit anti-NP^b idiotype antibodies (RaId) was used to quantitate the expression by immune spleen and thymus cells of NP^bId, the characteristic Id of the λ1-containing antibodies made by C57BL/6 (B6) mice to the (4-hydroxy-3-nitrophenyl)acetyl (NP) group. Direct binding of RaId by B and T cell preparations reached a maximum of 12 ng RaId per 10⁸ cells at 7 days after immunization. Spleen T cell preparations maintained similar levels of binding after positive selection for Thy-1.2⁺ cells and overnight culture. RaId binding was also demonstrated for immune B6 thymus cells and for spleen and thymus cells of immune SJL mice, which have the appropriate heavy chain allotype for NP^bId expression but have only barely detectable serum Id. However, the NP^bId of T and B cell preparations were indistinguishable by (a) the susceptibility of RaId binding by the cells to inhibition by hapten or by antibodies to the variable regions of λ light chains (anti-V_λ) and by (b) the ability of anti-V_λ and of monoclonal antibodies to the constant region of λ1 chains (anti-C_λ1) to immunoprecipitate antigen (NP₁₀-bovine serum albumin)-binding proteins from detergent extracts of isotopically labeled cells. The results strongly imply that virtually all of the NP^bId of T cell preparations is due to conventional NP^bId antibody that is tightly bound to T cells. The results do not, however, exclude the possibility that the T cell preparations contain a trace amount (≤ 1 ng/10⁸ cells) of unusual NP^bId-like molecules that lack λ chains.     

Self-Reported Zygosity and the Equal-Environments Assumption for Psychiatric Disorders in the Vietnam Era Twin Registry

The equal-environments assumption (EEA) in twin studies of psychiatric disorders assumes that the family environment which contributes to risk for a disorder is equally correlated between monozygotic (MZ) and dizygotic (DZ) twin pairs. In a study of psychiatric disorders in female twins, Kendler and colleagues (1993) have demonstrated the utility of a test of the EEA which includes a specified family environmental factor defined by using measures of perceived zygosity. We tested the EEA assumption among 3155 male—male twin pair members of the Vietnam Era Twin Registry for the following DSM-III-R lifetime disorders: alcohol dependence, marijuana dependence, any illicit drug dependence, nicotine dependence, major depression, and posttraumatic stress disorder. The majority of MZ (81.6%; n = 1593) and DZ (90.2%; n = 1086) twin pairs agreed with the investigator's assigned zygosity. The best-fitting model for each of these disorders did not allow for a specified family environmental influence. These results support the usefulness of perceived zygosity in tests of the EEA. In male twin pairs, perceived zygosity has little impact on twin similarity for common psychiatric disorders.     

Acute pulmonary responses among automobile workers exposed to aerosols of machining fluids

Previous investigations of workers exposed to machining fluids have shown increased rates of cough and phlegm and have shown that these exposures may cause occupational asthma. To examine acute responses to these agents, cross-shift lung function changes related to machining fluid aerosols among 89 machine operators at two factories producing automobile parts were measured and compared with the findings for 42 unexposed assembly workers studied similarly at the same factories. Workers wore a personal air-sampling device on a Monday and Friday of a working week, and spirometry was performed before and after the work shifts on both days. On Mondays, a 5% or greater decrease in the forced expiratory volume in 1-second (FEV1), regarded as an "FEV1-response," occurred in 23.6% of the machinists and in only 9.5% of the assembly workers (relative risk = 2.5, p less than .05). After adjusting statistically for a history of childhood asthma, for smoking prior to lung function testing, and for race, odds ratios for an FEV1-response of 4.4 among workers exposed to aerosols of straight mineral oils, 5.8 for oil emulsions, and 6.9 for synthetic fluids were found. The FEV1-responses on Fridays were similar to those on Mondays. There was no progressive decline in FEV1 over the work week. Personal air samples, collected with a two-stage impactor, allowed aerosol masses to be measured in three size fractions: less than 3.5 microns, 3.5-9.8 microns, and greater than 9.8 microns aerodynamic diameter. Exposure levels to each type of machining fluid were remarkably similar within each size fraction and for total aerosol levels. Total aerosol concentrations for assembly workers ranged from 0.07 to 0.44 mg/M3, and for machinists from 0.16 to 2.03 mg/m3. Inhalable particle (less than or equal to 9.8 microns) levels were derived from the sum of the air concentrations in the two smallest-size fractions, and significant cross-shift decrements in FEV1 on Mondays and Fridays were associated with inhalable aerosol levels greater than 0.20 mg/m3. These findings show that acute airflow obstruction is associated with exposures to aerosols of various machining fluids and that airway responses occur well below current recommended exposure limits.     

Immunophenotypic characterization of sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease)

Histochemical and immunohistochemical studies have been reported in only a few cases of sinus histiocytosis with massive lymphadenopathy (SHML) to date. These indicate that SHML cells belong to the macrophage/histiocyte family, but their exact origin is still unknown. We determined the antigenic phenotype of SHML cells in sections from 20 cases of routinely fixed, paraffin-embedded tissue and from two cases of fresh frozen tissue using a broad panel of antibodies to macrophage/histocyte, B-, and T-cell antigens. SHML cells expressed the following: (1) S-100 protein, (2) "pan-macrophage" antigens such as EBM11, HAM 56, and Leu-M3, (3) antigens functionally associated with phagocytosis (Fc receptor for IgG, complement receptor 3), and lysosomal activity (lysozyme, alpha 1-antichymotrypsin, and alpha 1-antitrypsyn), (4) antigens associated with early inflammation (Mac-387, 27E10), (5) antigens commonly found on monocytes, but not tissue macrophages (OKM5, Leu-M1), and (6) "activation" antigens (Ki-1 and receptors for transferrin and interleukin 2). These data suggest that SHML cells are true functionally activated macrophages that may be recently derived from circulating monocytes.     

Electromyography of respiratory muscles in amyotrophic lateral sclerosis.

We reviewed the records of 52 amyotrophic lateral sclerosis (ALS) patients examined between 1995 and 2000 who had needle electromyography (EMG) of their respiratory muscles, including the diaphragm, at or near the time of their diagnosis. With respiratory function testing, patients with abnormal diaphragmatic EMG at diagnosis (Group 1, n=23) had significantly lower forced vital capacity (FVC), lower daytime arterial PO(2) and higher PCO(2) measurements (p<0.05) than patients with normal diaphragmatic EMG (Group 2, n=29). Twenty-eight percent of the patients without symptoms or signs of respiratory insufficiency at the time they were examined had an abnormal diaphragm EMG. Mean survival of Groups 1 and 2 were similar. However, sub-analysis of patients within each group, comparing those treated with non-invasive positive pressure ventilation (NIPPV) with those not treated, showed that treated patients in Group 1 (abnormal diaphragm EMG) survived significantly longer (p<0.05) than untreated patients. They also started NIPPV earlier than treated patients in Group 2. We conclude that respiratory muscle EMG was simply and safely performed on ALS patients at or around the time of diagnosis. The procedure can detect sub-clinical respiratory muscle dysfunction. The technique used for EMG of the respiratory muscles, its pitfalls and contraindications are also reviewed.