Choroid Plexus-Infiltrating T Cells as Drivers of Murine Neuropsychiatric Lupus

OBJECTIVE

T cells are critical in the pathogenesis of systemic lupus erythematosus (SLE) in that they secrete inflammatory cytokines, help autoantibody production, and form autoreactive memory T cells. Although the contribution of T cells to several forms of organ-mediated damage in SLE has been previously demonstrated, the role of T cells in neuropsychiatric SLE (NPSLE), which involves diffuse central nervous system manifestations and is observed in 20-40% of SLE patients, is not known. Therefore, we conducted this study to evaluate how behavioral deficits are altered after depletion or transfer of T cells, to directly assess the role of T cells in NPSLE.

METHODS

MRL/lpr mice, an NPSLE mouse model, were either systemically depleted of CD4+ T cells or intracerebroventricularly injected with choroid plexus (CP)-infiltrating T cells and subsequently evaluated for alterations in neuropsychiatric manifestations. Our study end points included evaluation of systemic disease and assessment of central nervous system changes.

RESULTS

Systemic depletion of CD4+ T cells ameliorated systemic disease and cognitive deficits. Intracerebroventricular injection of CP-infiltrating T cells exacerbated depressive-like behavior and worsened cognition in recipient mice compared with mice who received injection of splenic lupus T cells or phosphate buffered saline. Moreover, we observed enhanced activation in CP-infiltrating T cells when cocultured with brain lysate-pulsed dendritic cells in comparison to the activation levels observed in cocultures with splenic T cells.

CONCLUSION

T cells, and more specifically CP-infiltrating antigen-specific T cells, contributed to the pathogenesis of NPSLE in mice, indicating that, in the development of more targeted treatments for NPSLE, modulation of T cells may represent a potential therapeutic strategy.

Targeting retinoic acid receptor alpha-corepressor interaction activates chaperone-mediated autophagy and protects against retinal degeneration

Chaperone-mediated autophagy activity, essential in the cellular defense against proteotoxicity, declines with age, and preventing this decline in experimental genetic models has proven beneficial. Here, we have identified the mechanism of action of selective chaperone-mediated autophagy activators previously developed by our group and have leveraged that information to generate orally bioavailable chaperone-mediated autophagy activators with favorable brain exposure. Chaperone-mediated autophagy activating molecules stabilize the interaction between retinoic acid receptor alpha - a known endogenous inhibitor of chaperone-mediated autophagy - and its co-repressor, nuclear receptor corepressor 1, resulting in changes of a discrete subset of the retinoic acid receptor alpha transcriptional program that leads to selective chaperone-mediated autophagy activation. Chaperone-mediated autophagy activators molecules activate this pathway in vivo and ameliorate retinal degeneration in a retinitis pigmentosa mouse model. Our findings reveal a mechanism for pharmacological targeting of chaperone-mediated autophagy activation and suggest a therapeutic strategy for retinal degeneration.

Gomez-Sintes et al. have developed small molecules that selectively activate chaperone-mediated autophagy by stabilizing the interaction between retinoic acid receptor alpha and its co-repressor N-CoR1. They demonstrate the protective effect of boosting chaperone-mediated autophagy against retinal degeneration.

Who do we gain? Enhancement of blood supplies by additional testing for donors who travel

AIMS/OBJECTIVES

To describe the impact of additional testing on the England blood supply.

BACKGROUND

The blood service for England, NHS Blood and Transplant, applies a system of deferral and testing to donors with potential exposure to Chagas disease, malaria and West Nile virus; however, testing costs must be justified. Here, we describe the donations and donors gained by testing.

METHODS

Donation testing results and demographic data on donors in England where additional testing was applied were analysed in 2012-2016. The total number and proportion of donations tested, reactive and confirmed positive were calculated. Proportions of donors requiring additional tests were calculated by ethnic group for first-time and repeat donors.

RESULTS

Additional testing for travel was applied to 3·5% of NHSBT blood donations between 2012 and 2016. Over 98% of these tests were non-reactive. Only malaria tests were confirmed positive, in 1·7% of donations tested. In first-time donors, 45 and 40% of Asian and Black donors required an additional test, respectively, mainly for malaria. Testing for West Nile virus increased from 1·5% in 2012 to 2·2% of donations in 2016.

CONCLUSION

The majority of additional tests were screened negative, allowing approximately 64 000 donations to be released for issue annually. Donors most affected by malaria testing were more likely to have rare blood groups and be targeted for recruitment, whereas those given West Nile virus testing were mainly regular donors required for continuity of supply. These data show differences in the characteristics of donors by test and can be used to inform decisions about additional testing and deferrals.

The negative effect of lipid challenge on autophagy inhibits T cell responses

Obesity is associated with changes in the immune system that significantly hinder its ability to mount efficient immune responses. Previous studies have reported a dysregulation of immune responses caused by lipid challenge; however, the mechanisms underlying that dysregulation are still not completely understood. Autophagy is an essential catabolic process through which cellular components are degraded by the lysosomal machinery. In T cells, autophagy is an actively regulated process necessary to sustain homeostasis and activation. Here, we report that CD4⁺ T cell responses are inhibited when cells are challenged with increasing concentrations of fatty acids. Furthermore, analysis of T cells from diet-induced obese mice confirms that high lipid load inhibits activation-induced responses in T cells. We have found that autophagy is inhibited in CD4⁺ T cells exposed in vitro or in vivo to lipid stress, which causes decreased autophagosome formation and degradation. Supporting that inhibition of autophagy caused by high lipid load is a key mechanism that accounts for the effects on T cell function of lipid stress, we found that ATG7 (autophagy-related 7)-deficient T cells, unable to activate autophagy, did not show additional inhibitory effects on their responses to activation when subjected to lipid challenge. Our results indicate, thus, that increased lipid load can dysregulate autophagy and cause defective T cell responses, and suggest that inhibition of autophagy may underlie some of the characteristic obesity-associated defects in the T cell compartment.Abbreviations: ACTB: actin, beta; ATG: autophagy-related; CDKN1B: cyclin-dependent kinase inhibitor 1B; HFD: high-fat diet; IFNG: interferon gamma; IL: interleukin; MAPK1/ERK2: mitogen-activated protein kinase 1; MAPK3/ERK1: mitogen-activated protein kinase 3; MAPK8/JNK: mitogen-activated protein kinase 8; LC3-I: non-conjugated form of MAP1LC3B; LC3-II: phosphatidylethanolamine-conjugated form of MAP1LC3B; MAP1LC3B: microtubule-associated protein 1 light chain 3 beta; MS: mass spectrometry; MTOR: mechanistic target of rapamycin kinase; NFATC2: nuclear factor of activated T cells, cytoplasmic, calcineurin dependent 2; NLRP3: NLR family, pyrin domain containing 3; OA: oleic acid; PI: propidium iodide; ROS: reactive oxygen species; STAT5A: signal transducer and activator of transcription 5A; TCR: T cell receptor; T_H1: T helper cell type 1.

Chaperone mediated autophagy and T cell function

Autophagy is a cellular quality control mechanism that degrades and recycles cellular components in the lysosome to maintain cellular homeostasis and to regulates protein levels in response to stimuli. Chaperone mediated autophagy (CMA) is a selective form of autophagy that targets soluble cytoplasmic proteins for degradation. In CMA, the chaperone Hsc70 recognizes and binds a CMA-targeting motif in the substrate and brings it to the LAMP-2A receptor on the lysosomal membrane. The receptor multimerizes and the substrate translocates into the lysosome to be degraded. We have previously reported that CMA is upregulated in activated CD4+ T cells, where it is required to support proliferation and cytokine production. However, the signaling pathways that regulate CMA activity during the immune response and cell type-specific functions of CMA are not fully characterized.

We have found that retinoic acid receptor alpha (RARα) signaling inhibits CMA, and that modulation of RARα signaling with chemically modified retinoic acid derivatives leads to CMA activation. We have used these novel CMA activators to identify target genes involved in the regulation of CMA in T cells. Furthermore, our data supports that LAMP-2A expression and CMA activity are down-regulated in aged T cells, which correlates with the age-associated decreases in T cell function. Interestingly, genetic restoration of LAMP-2A expression in aged cells enhances T cell responses. Therefore, we have explored how CMA activating compounds may restore CMA activity in aged T cells boosting T cell function.

Dissecting the decline of hepatitis C in first-time donors in England and Wales

BACKGROUND AND OBJECTIVES

The rate of confirmed hepatitis C virus (HCV) cases, in first-time donors, is much lower in 2015 than 20 years ago. We investigate reasons for the decline.

MATERIALS AND METHODS

HCV rates were analysed by gender and birth cohort for 1996 to 2015 and ethnic group for 2006 to 2015. Variables for confirmed positive cases were compared for two ten-year periods (1996 to 2005 and 2006 to 2015) including genotyping data for 2006 to 2015.

RESULTS

There were 2007 confirmed HCV cases identified between 1996 and 2015. The rate per 100 000 donations fell from 78·6 in 1996 to 26·9 by 2015. By birth cohort, HCV rates were highest in donors born in the 1950s and 1960s who contributed a decreasing proportion of first-time donors. Between 2006 and 2015, there was no significant decline in HCV rate. The HCV-positive donor profile has changed in the last 10 years with increased proportions of younger donors, donors born abroad and decreased reported injecting drug use. Genotype 1a remains predominate, but genotype 1b has increased associated with this change in birth cohort and ethnicity.

CONCLUSION

The decline in number and rate of confirmed HCV-positive first-time donors is mainly due to a decrease in first-time donors born before 1970, with the highest rate of HCV. However, the decline has slowed and the profile of HCV-positive first-time donors is changing. A better understanding of behaviour and sources of HCV in younger and ethnic minority donors are needed.

Gene-environment interplay in depressive symptoms: moderation by age, sex, and physical illness

BACKGROUND

Numerous factors influence late-life depressive symptoms in adults, many not thoroughly characterized. We addressed whether genetic and environmental influences on depressive symptoms differed by age, sex, and physical illness.

METHOD

The analysis sample included 24 436 twins aged 40-90 years drawn from the Interplay of Genes and Environment across Multiple Studies (IGEMS) Consortium. Biometric analyses tested age, sex, and physical illness moderation of genetic and environmental variance in depressive symptoms.

RESULTS

Women reported greater depressive symptoms than men. After age 60, there was an accelerating increase in depressive symptom scores with age, but this did not appreciably affect genetic and environmental variances. Overlap in genetic influences between physical illness and depressive symptoms was greater in men than in women. Additionally, in men extent of overlap was greater with worse physical illness (the genetic correlation ranged from near 0.00 for the least physical illness to nearly 0.60 with physical illness 2 s.d. above the mean). For men and women, the same environmental factors that influenced depressive symptoms also influenced physical illness.

CONCLUSIONS

Findings suggested that genetic factors play a larger part in the association between depressive symptoms and physical illness for men than for women. For both sexes, across all ages, physical illness may similarly trigger social and health limitations that contribute to depressive symptoms.

Getting personal with blood donors - the rationale for, methodology of and an overview of participants in the UK blood donor survey

OBJECTIVE

To design and pilot a survey of UK blood donors to assess, on a large scale, their understanding of and compliance with the donor selection guidelines (DSG).

BACKGROUND

Compliance with the DSG is important for maintaining blood safety, however, little is currently known about the extent of this among UK donors.

MATERIALS AND METHODS

The online, unlinked survey was based on the donor health check form with a focus on behaviours associated with blood borne infections, sexual contact, drug use and travel. The survey materials were reviewed by a donor focus group and the survey was piloted among 2982 UK donors. Percentage responses were calculated, complaints monitored and answers to questions reviewed. The survey went live in 2013; 225 091 donors were invited via email to participate followed by two reminders.

RESULTS

The survey was well received by the focus group, with little concern about the sensitive and personal questions. Their feedback led to important refinement in the survey materials. In the pilots, 21·0% (627/2982) responded, a reminder was necessary to achieve this. Among responders, there was evidence of non-compliance and test seeking behaviour, and no evidence that intention to donate again was affected. In the live survey, 29% (65 439) responded; responders were generally representative of donors overall.

CONCLUSION

A large scale survey of donor compliances is feasible, acceptable and effective in ascertaining appropriate information; involving donors and the blood services in the development stages through a focus group and pilots was important to achieve this.

Serotonin concentrations in platelets, plasma, mitral valve leaflet, and left ventricular myocardial tissue in dogs with myxomatous mitral valve disease

HYPOTHESIS/OBJECTIVES

Altered serotonin (5-hydroxytryptamine, 5HT) signaling is postulated in development and progression of canine myxomatous mitral valve disease (MMVD). Little is known regarding platelet, plasma, valvular, or myocardial 5HT concentration ([5HT]) in affected dogs. We quantified [5HT] in platelet-rich plasma (PRP), platelet-poor plasma (PPP), mitral valve leaflets (MV), and left ventricular myocardium (LV).

ANIMALS

Forty-five dogs comprised 4 plasma groups of Cavalier King Charles Spaniels (CKCS) or non-CKCS, either healthy (CON) or MMVD affected: CKCS CON (n = 12); non-CKCS CON (n = 8); CKCS MMVD (n = 14); non-CKCS MMVD (n = 11). Twenty-four dogs comprised 3 tissue groups: MMVD (n = 8); other-HD (heart disease) (n = 7); non-HD, extracardiac disease (n = 9).

METHODS

High-performance liquid chromatography measured PRP, PPP, MV, and LV [5HT].

RESULTS

Platelet-rich plasma platelet [5HT] was greater in CKCS CON (1.83 femtograms/platelet [fg/plt]; range, 0.20-4.76; P = .002), CKCS MMVD (1.58 fg/plt; range, 0.70-4.03; P = .005), and non-CKCS MMVD (1.72 fg/plt; range, 0.85-4.44; P = .003) versus non-CKCS CON (0.92 fg/plt; range, 0.63-1.30). There was no group difference in PPP [5HT]. MV [5HT] was significantly higher in MMVD (32.4 ng/mg; range, 8.4-106.7) versus non-HD (3.6 ng/mg; range, 0-28.3; P = .01) and LV [5HT] was significantly higher in MMVD (11.9 ng/mg; range, 4.0-104.8) versus other-HD (0.9 ng/mg; range, 0-10.1; P = .011) and non-HD (2.5 ng/mg; range, 0-6.9; P = .001).

CONCLUSIONS AND CLINICAL IMPORTANCE

Platelet [5HT] was highest in healthy CKCS and both MMVD groups, but plasma [5HT] showed no group differences. Tissue [5HT] was highest in MV and LV of MMVD-affected dogs, suggesting altered 5HT signaling as a potential feature of MMVD. Interactions of platelet, valvular, and myocardial 5HT signaling warrant further investigation.

Serum serotonin concentrations in dogs with degenerative mitral valve disease

BACKGROUND

Increased serotonin (5HT) signaling has been implicated in valvular disease of humans and animals, including canine degenerative mitral valve disease (DMVD). High circulating 5HT concentration is a potential source of increased signaling, and serum 5HT concentrations have not been previously reported in dogs with DMVD.

HYPOTHESIS

Dogs with DMVD and small breed dogs predisposed to DMVD have higher serum 5HT concentrations than large breed controls.

ANIMALS

Fifty dogs affected with DMVD, 34 dogs predisposed to DMVD but without cardiac murmur or echocardiographic evidence of DMVD, and 36 healthy large breed control dogs.

METHODS

Prospective analysis. Serum 5HT concentration was measured by an ELISA test.

RESULTS

Median serum 5HT concentration was significantly higher in dogs with DMVD and in dogs predisposed to DMVD as compared with controls (DMVD, 765.5 ng/mL [interquartile range, 561.3-944.4]; predisposed, 774.9 ng/mL [528.3-1,026]; control, 509.8 ng/mL [320.8-708.8]; P= .0001). Subgroup analysis of predisposed dogs indicated significantly higher serum 5HT concentrations in Cavalier King Charles Spaniel (CKCS) dogs than in other breeds (CKCS, 855.0 ng/mL [635.8-1,088]; non-CKCS, 554.2 ng/mL [380.6-648.4]; P= .0023). Age, platelet count, and platelet morphology were not correlated with 5HT concentration in any group.

CONCLUSIONS AND CLINICAL IMPORTANCE

Dogs with DMVD had significantly higher serum 5HT concentrations when compared with large breed control dogs. Healthy CKCS dogs had significantly higher serum 5HT concentrations than other healthy dogs predisposed to DMVD. Additional investigation into a possible role of 5HT in the pathogenesis of DMVD is warranted.

Decreased triadin and increased calstabin2 expression in Great Danes with dilated cardiomyopathy

BACKGROUND

Dilated cardiomyopathy (DCM) is a common cardiac disease of Great Dane dogs, yet very little is known about the underlying molecular abnormalities that contribute to disease.

OBJECTIVE

Discover a set of genes that are differentially expressed in Great Dane dogs with DCM as a way to identify candidate genes for further study as well as to better understand the molecular abnormalities that underlie the disease.

ANIMALS

Three Great Dane dogs with end-stage DCM and 3 large breed control dogs.

METHODS

Prospective study. Transcriptional activity of 42,869 canine DNA sequences was determined with a canine-specific oligonucleotide microarray. Genome expression patterns of left ventricular tissue samples from affected Great Dane dogs were evaluated by measuring the relative amount of complementary RNA hybridization to the microarray probes and comparing it with expression from large breed dogs with noncardiac disease.

RESULTS

Three hundred and twenty-three transcripts were differentially expressed (> or = 2-fold change). The transcript with the greatest degree of upregulation (+61.3-fold) was calstabin2 (FKBP12.6), whereas the transcript with the greatest degree of downregulation (-9.07-fold) was triadin. Calstabin2 and triadin are both regulatory components of the cardiac ryanodine receptor (RyR2) and are critical to normal intracellular Ca2+ release and excitation-contraction coupling.

CONCLUSION AND CLINICAL IMPORTANCE

Great Dane dogs with DCM demonstrate abnormal calstabin2 and triadin expression. These changes likely affect Ca2+ flux within cardiac cells and may contribute to the pathophysiology of disease. Microarray-based analysis identifies calstabin2, triadin, and RyR2 function as targets of future study.

Effect of azotemia on serum N-terminal proBNP concentration in dogs with normal cardiac function: a pilot study

OBJECTIVES

To evaluate amino-terminal pro-B type natriuretic peptide (NT-proBNP) concentration in dogs with renal dysfunction and normal cardiac structure and function.

ANIMALS

Eight dogs with renal disease, 23 healthy control dogs.

METHODS

Serum NT-proBNP concentration was measured in healthy dogs and dogs with renal disease using an ELISA validated for use in dogs. Affected dogs were eligible for inclusion if renal dysfunction was diagnosed based on urinalysis and serum chemistry, and if they were free of cardiovascular disease based on physical exam, systolic blood pressure, and echocardiography.

RESULTS

The geometric mean serum NT-proBNP concentration was significantly higher in dogs with renal disease (617 pmol/L; 95% CI, 260-1467 pmol/L) than in healthy control dogs (261 pmol/L; 95% CI, 225-303 pmol/L; P=0.0014). There was a modest positive correlation between NT-proBNP and BUN and creatinine. Median NT-proBNP concentration was not significantly different between groups when indexed to BUN (median NT-proBNP:BUN ratio; renal, 14.2, IQR, 3.93-17.7 vs. control, 16.3, IQR, 9.94-21.2; P=0.29) or creatinine (median NT-proBNP:creatinine ratio; renal, 204, IQR, 72.6-448 vs. control, 227, IQR, 179-308; P=0.67).

CONCLUSION

Dogs with renal disease had significantly higher mean serum concentration of NT-proBNP than control dogs. Renal function should be considered when interpreting NT-proBNP results as concentrations may be falsely elevated in dogs with renal dysfunction and normal cardiac function. The effect of renal disease was lessened by indexing NT-proBNP to BUN or creatinine. Future studies in dogs with both renal and heart disease are warranted.

Benign breast disease and breast cancer risk in young women

Abstract #62

Background: Breast cancer is the leading cause of cancer deaths in younger women (25 to 49 years of age). Young women with breast cancer also have worse overall survival and increased risk of recurrence compared to older women with breast cancer. Innovative approaches to understanding risk factors and tissue characteristics for the younger population can improve understanding of breast cancer etiology and enhance risk-stratification for these women. This study was aimed at examining breast cancer risk factors among young women (<50 years) with BBD. Materials and Methods: Utilizing the Mayo Clinic Surgical and Pathology Indices, women ages 18 to 85 who had benign excisional breast biopsy between January 1, 1967 and December 31, 1991 were identified. The diagnosis of breast cancer served as the study endpoint and was determined using the Mayo medical record and questionnaire information from study participants. The breast pathologist, blinded to the initial diagnosis and clinical outcome, performed pathology review. BBD was classified as non-proliferative disease (NPD), proliferative disease without atypia (PDWA), or atypical hyperplasia (AH). Age-related lobular involution (reduction in number and size of acini per lobule) was classified as none-0%, partial- 1 to74%, or complete- >75% involution. Relative risk (RR) was estimated by comparing the number of observed breast cancers with the number expected, based on breast cancer rates in the Iowa Surveillance, Epidemiology, and End Results registry. Results: Of the 9376 women in the Mayo BBD cohort, 4460 women were aged <50 years at BBD diagnosis and formed the study cohort. The mean age at BBD diagnosis was 39.4 (+ 8.3) years. With a median follow-up of 20 years, 326 breast cancer cases were identified. The histologic findings were NPD in 72% of women, PDWA in 26%, and AH in 2%. The relative risk of breast cancer for the overall cohort of young women with BBD was 1.5 (95% CI [1.4, 1.7]). The relative risk among those with AH was 6.9 (95% CI [4.6, 10.1), compared with a RR of 2.0 (95% CI [1.7, 2.4]) for PDWA, and RR of 1.2 (95% CI [1.0, 1.4]) for NPD. Risk was associated with extent of lobular involution (RR for no involution was 1.7 (95%CI [1.4, 2.1]); partial involution 1.4 (95%CI [1.2, 1.7]); complete involution 0.7 (95%CI [0.3, 1.4]). Family history was available for 83% of the cohort and RR was 2.2 (95% CI [1.7, 2.8]) for women with strong family history and was 1.3 (95% CI [1.1, 1.6]) for women with no family history. Discussion: Young women with BBD are at increased risk of breast cancer. Risk is high in women with atypical hyperplasia, and those with a family history of breast cancer. Lobular involution is associated with reduced breast cancer risk in this population, suggesting a role in modifying breast cancer risk. These findings suggest the need for further research in this population, along with tissue-based studies to examine the processes leading to breast cancer, and enable identification of those women at highest risk.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 62.

A novel breast tissue feature strongly associated with risk of breast cancer

Abstract #5008

Background: Accurate, individualized risk prediction for breast cancer is lacking. Tissue-based features, such as the terminal duct lobular unit (TDLU), may help to stratify women into different risk levels as breast lobules are the anatomic sites of origin of breast cancer. As women age, these lobular structures should regress, which results in reduced breast cancer risk. Regression, however, does not occur in all women.
 Materials and Methods: We have quantified the extent of lobule regression on a benign breast biopsy in 85 breast cancer cases and 142 age-matched controls from the Mayo Benign Breast Disease Cohort, by determining number of acini/lobule and lobular area. We also calculated Gail model 5-year predicted risks for these women.
 Results: There is a step-wise increase in breast cancer risk with increasing numbers of acini/lobule (p=0.0004). Adjusting for Gail model score, parity, histology, and family history did not attenuate this association.
 
 Lobular area was similarly associated with risk. The Gail model estimates were associated with risk of breast cancer (p=0.03). We examined the individual accuracy of these measures using the concordance (c) statistic. The Gail model c-statistic was 0.60 (95% CI; 0.50-0.70); the acinar count c-statistic was 0.65 (95% CI; 0.54-0.75). Combining acinar count and lobular area, the c-statistic was 0.68 (95% GI; 0.58-0.78). Adding the Gail model to these did not improve the c-statistic.
 
 Discussion: Novel, tissue-based features that reflect the status of a woman's normal breast lobules are strongly associated with breast cancer risk. These features appear to provide more accurate risk assessment than the currently used Gail model.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5008.

Histologic markers of mammographic breast density: core-needle biopsy tissue from healthy volunteers

Abstract #4037

Background: Mammographic breast density is a strong and consistent risk factor for breast cancer. Women with dense tissue in over 60 to 75% of the breast are at 4 to 6 times greater risk than women with little or no density. However, the biology of breast density is not well understood and studies at the tissue level are limited. We present the first report of a tissue-based study of breast density, sampling mammographically dense and non-dense areas of the breast of healthy women with the goal of examining histologic correlates.
 Materials and Methods: Healthy women volunteers aged 40 to 85 years, with no breast symptoms, normal screening mammogram within 6 months, and no personal history of breast cancer were considered eligible. Women with breast-related symptoms, those on endocrine therapy, or with bleeding tendencies were excluded from participation. Sixty consecutive eligible women were enrolled in the study- results are based on the first 34 participants. Eligible women underwent an ultrasound-guided, core-needle breast biopsy of mammographically dense and non-dense areas of the breast, performed by a single experienced radiologist. Quantitative assessment of breast tissue from dense and non-dense areas was performed for epithelium, stroma, and fat. In addition, we assessed the difference in the extent of lobular involution (complete, partial and none) between dense and non-dense areas. We used means and SD to describe distributions in each tissue type. Signed rank test was used to assess within woman differences between dense and non-dense tissue.
 Results: The mean age of the participants was 50.1 years (range 40 to 79 years). The histological findings are outlined below.
 
 Dense tissue is comprised of increased stroma and epithelium and decreased fat, consistent with prior reports on breast density. The finding of 'no involution' was greater in dense tissue compared to non-dense tissue (24% versus 8.8%); non-dense tissue had greater proportion of complete involution compared to dense tissue (82.5% versus 35.2%).
 Discussion: This report is the first to quantify histology in tissue sampled from dense and non-dense regions of the healthy breast. We find a dramatic difference in tissue composition between dense and non-dense tissue in the breast. Future studies using this tissue to assess molecular markers will further help to characterize pathways through which density may increase breast cancer risk.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4037.

Computational studies of Family A and Family B GPCRs

A full picture of the similarities between Family A and Family B GPCRs (G-protein coupled receptors) has been frustrated by the lack of clear homology between the respective sequences. Here, we review previous computational studies on GPCR dimerization in which the putative dimerization interfaces have been analysed using entropy, the ET (evolutionary trace) method and related methods. The results derived from multiple sequence alignments of Family A subfamilies have been mapped on to the rhodopsin crystal structure using standard alignments. Similarly, the results for the Family B alignments have been mapped on to the rhodopsin crystal structure using the 'cold-spot' alignment. For both Family A and Family B GPCRs, the sequence analysis indicates that there are functional sites on essentially all transmembrane helices, consistent with the parallel daisy chain model of GPCR oligomerization in which each GPCR makes interactions with a number of neighbouring GPCRs. The results are not too sensitive to the quality of the alignment. Molecular Dynamics simulations of the activation process within a single transmembrane bundle of the rhodopsin and the beta(2)-adrenergic receptor have been reviewed; the key observation, which is consistent with other computational studies, is that there is a translation and bending of helix 6, which contributes to a significant opening out of the intracellular face of the receptor, as shown in the accompanying movies. The simulations required the application of specific experiment-derived harmonic and half-harmonic distance restraints and so the application of such simulations to Family B GPCRs requires considerable care because of the alignment problem. Thus, in order to address the alignment problem, we have exploited the observation that GCR1, a plant GPCR, has homology with Family A, Family B and Family E GPCRs. The resulting alignment for transmembrane helix 3 is presented.

Dimerization of G-protein-coupled receptors

The evolutionary trace (ET) method, a data mining approach for determining significant levels of amino acid conservation, has been applied to over 700 aligned G-protein-coupled receptor (GPCR) sequences. The method predicted the occurrence of functionally important clusters of residues on the external faces of helices 5 and 6 for each family or subfamily of receptors; similar clusters were observed on helices 2 and 3. The probability that these clusters are not random was determined using Monte Carlo techniques. The cluster on helices 5 and 6 is consistent with both 5,6-contact and 5,6-domain swapped dimer formation; the possible equivalence of these two types of dimer is discussed because this relates to activation by homo- and heterodimers. The observation of a functionally important cluster of residues on helices 2 and 3 is novel, and some possible interpretations are given, including heterodimerization and oligomerization. The application of the evolutionary trace method to 113 aligned G-protein sequences resulted in the identification of two functional sites. One large, well-defined site is clearly identified with adenyl cyclase, beta/gamma and regulator of G-protein signaling (RGS) binding. The other G-protein functional site, which extends from the ras-like domain onto the helical domain, has the correct size and electrostatic properties for GPCR dimer binding. The implications of these results are discussed in terms of the conformational changes required in the G-protein for activation by a receptor dimer. Further, the implications of GPCR dimerization for medicinal chemistry are discussed in the context of these ET results.

Deficits in controlled processing may predict dementia: a twin study

This study tested for differential patterns of cognitive decline in 33 twin pairs for which both were nondemented, but 1 member of the pair went on to develop dementia. Compared with their nondemented twin partners, twins who later developed dementia already showed poorer performance on tests of memory and attention, visuospatial-reasoning skills, and perceptual speed and the Mini-Mental State Examination (MMSE). The authors suggest that this cluster of tests reflects deficits in controlled rather than automatic cognitive processes. Nondemented twin partners of the twins who became demented were also compared with 33 matched controls selected from pairs in which both members remained nondemented. Nondemented twin partners scored lower than matched controls on tests of verbal ability, memory and attention, and perceptual speed and the MMSE. This finding indicates that nondemented twin partners of demented twins are at elevated risk themselves for becoming demented, and further suggests that certain areas of cognition are compromised prior to diagnosis of dementia.

Lipid-facing correlated mutations and dimerization in G-protein coupled receptors

A correlated mutation analysis has been performed on the aligned protein sequences of a number of class A G-protein coupled receptor families, including the chemokine, neurokinin, opioid, somatostatin, thyrotrophin and the whole biogenic amine family. Many of the correlated mutations are observed flanking or neighbouring conserved residues. The correlated residues have been plotted onto the transmembrane portion of the rhodopsin crystal structure. The structure shows that a significant proportion of the correlated mutations are located on the external (lipid-facing) region of the helices. The occurrence of these highly correlated patterns of change amongst the external residues suggest that they are sites for protein-protein interactions. In particular, it is suggested that the correlated residues may be involved in either large conformational changes, the formation of heterodimers or homodimers (which may be domain swapped) or oligomers required for activation or internalization. The results are discussed in the light of the subtype-specific heterodimerization observed for the chemokine, opioid and somatostatin receptors.

Towards new transition metal-based hypoxic selective agents for therapy and imaging

The greater lability of Co(II) relative to Co(III) can potentially be used to achieve selective delivery of nitrogen mustard type molecules to hypoxic cells. Attempts to improve the stability of the Co(II) state by utilising tripodal tetradentate ligands are described, together with the results of DF calculations. Rhenium has two beta-emitting isotopes (186)Re and (188)Re that have potential for use to treat cancer if the complexes can be targeted with sufficient specificity. We describe some new rapid low temperature routes using hydrazines to labile Re(V) and Re(III) species which provide potential convenient access to a wide range of oxo- and diazenido-complexes. The synthesis of new Re(V) and Re(III) thiosemicarbazone complexes is presented in the context of obtaining hypoxic selective species. Copper(II) bis(thiosemicarbazone) complexes are known to be hypoxic selective and spectroscopic, cyclic voltammetric and computational studies of the mechanism are presented, together with the synthesis of new Cu(II) complexes directed towards the hypoxic selective delivery of nitrogen mustard type molecules.

Three-factor model of schizotypal personality: invariance across culture, gender, religious affiliation, family adversity, and psychopathology

Whilst the syndrome approach to schizotypy has recently demonstrated differential correlates of a three-factor model of schizotypal personality, variations in the nature of these factors question a basic assumption of this approach. This study tested competing models of the factor structure of schizotypal personality using the Schizotypal Personality Questionnaire (SPQ) in a sample of 1,201 Mauritians. Factor invariance across gender, ethnicity, family adversity, and religion and across a psychopathologically select group was also assessed. Results suggest that a three-factor model, Cognitive-Perceptual Deficits, Interpersonal Deficits, and Disorganization, underlies individual differences across widely varying groups. Other competing three-factor schizotypal personality models did not fit the data better. It is argued that the three-factor Disorganized model is a well-replicated model of DSM schizotypal personality in community samples but possibly not in some clinical samples.

Age-related differences and change in positive and negative affect over 23 years

Positive and negative affect, measured by the Bradburn Affect Balance Scale, were studied in a longitudinal sample spanning from 1971 to 1994. The sample (N = 2,804) represented 4 generations of families. Linear trend analyses compared generations over time for positive and negative affect and also examined the possible influences of neuroticism and extraversion on initial levels of affect and patterns of change in affect. Negative affect decreased with age for all generations, although the rate was attenuated among the oldest adults. Higher neuroticism scores also attenuated the decrease in negative affect across time. For positive affect, the younger and middle-aged adults showed marked stability, but the older group evidenced a small decrease over time. Higher levels of extraversion were related to more stability in positive affect.

Multivariate models of mixed assortment: phenotypic assortment and social homogamy for education and fluid ability

Phenotypic assortment is assumed to be the principal mechanism of spouse similarity in most biometrical studies. Other assortment mechanisms, such as social homogamy, may be plausible. Two models are presented that consider phenotypic assortment and social homogamy simultaneously (i.e., mixed assortment), where selective associations between social background factors (Model I) versus selective associations between total environments (Model II) distinguish the models. A series of illustrative analyses was undertaken for education and fluid ability available on a sample of 116 Swedish twin pairs and their spouses. On the basis of several fit criteria Model I was preferred over Model II. Both social homogamy and phenotypic assortment may contribute to spouse similarity for educational attainment and fluid ability. Furthermore, spouse similarity for fluid ability may arise indirectly from social homogamy and phenotypic assortment for educational attainment. Power analyses indicated greater observed power for Model I than Model II. Additional power analyses indicated that considerably more twin-spouse sets would be needed for Model II than Model I, to resolve social homogamy and phenotypic assortment. Effects of misspecification of mechanisms of spouse similarity are also briefly discussed.

Dimerization and domain swapping in G-protein-coupled receptors: a computational study

In recent years there has been an increasing number of reports describing G protein-coupled receptor (GPCR) dimerization and heterodimerization. However, the evidence on the nature of the dimers and their role in GPCR activation is inconclusive. Consequently, we present here a review of our computational studies on G protein-coupled receptor dimerization and domain swapping. The studies described include molecular dynamics simulations on receptor monomers and dimers in the absence of ligand, in the presence of an agonist, and in the presence of an antagonist (or more precisely an inverse agonist). Two distinct sequence-based approaches to studying protein interfaces are also described, namely correlated mutation analysis and evolutionary trace analysis. All three approaches concur in supporting the proposal that the dimerization interface includes transmembrane helices 5 and 6. These studies cannot distinguish between domain swapped dimers and contact dimers as the models used were restricted to the helical part of the receptor. However, it is proposed that for the purpose of signalling, the domain swapped dimer and the corresponding contact dimer are equivalent. The evolutionary trace analysis suggests that every GPCR family and subfamily (for which sufficient sequence data is available) has the potential to dimerize through this common functional site on helices 5 and 6. The evolutionary trace results on the G protein are briefly described and these are consistent with GPCR dimerization. In addition to the functional site on helices 5 and 6, the evolutionary trace analysis identified a second functional site on helices 2 and 3. Possible roles for this site are suggested, including oligomerization.

Cyclophosphamides as hypoxia-activated diffusible cytotoxins: a theoretical study

Cyclophosphamides have been in clinical use as anti-cancer drugs for a long time and much research has been directed towards reducing their side effects. Here we have performed a theoretical investigation into the possibility of designing bioreductive analogues of cyclophosphamides. Our calculations have employed semiempirical molecular orbital AM1-SM2 and PM3-SM3 calculations, as implemented in MOPAC 93, which include a modified Born method for the treatment of solvation. We have investigated the effect of bioreductive activation on the beta-elimination reaction that is central to the activation of cyclophosphamides. The approach was tested on two known bioreductive agents, including CB1954, and gave results in agreement with experiment. Non-local density functional calculations on CB1954 and its metabolites, including the radical anion, were in agreement with the semiempirical calculations. The calculations have identified a number of potentially novel bioreductive cyclophosphamides. In particular, our calculations identified compounds in which the initial one-electron reduction was not activating. Such compounds are likely to be more effective bioreductive agents, as the beta-elimination will not compete under oxic conditions with the important re-oxidation required for the protection of oxic tissue.

Breast MR imaging in patients with axillary node metastases and unknown primary malignancy

PURPOSE

To assess the usefulness of magnetic resonance (MR) imaging of the breast in patients with malignant axillary adenopathy and unknown primary malignancy.

MATERIALS AND METHODS

Between October 1993 and December 1997, 38 women with malignant axillary adenopathy and negative mammographic and physical examination findings underwent contrast material-enhanced MR imaging. Sixteen patients were excluded due to axillary tail cancer (n = 7), lack of follow-up (n = 4), second primary malignancy (n = 3), or chemotherapy before MR imaging (n = 2). The study population comprised the remaining 22 patients. Histopathologic findings were available in 20 patients; follow-up MR imaging findings were available in two patients.

RESULTS

MR imaging depicted a primary breast cancer in 19 patients (86%; identified at excisional biopsy or mastectomy in 17, resolved on follow-up MR images during treatment in two). MR imaging depicted 4-30-mm cancers (mean, 17 mm), which correlated closely with histopathologic size. Two patients (9%) had false-negative findings: (a) One had a 2-mm invasive ductal carcinoma, and (b) one had 17- and 20-mm invasive ductal carcinomas. Of the 19 patients, 11 underwent mastectomy, seven underwent breast-conservation therapy, and one did not undergo a surgical procedure.

CONCLUSION

MR imaging is very sensitive for the detection of mammographically and clinically occult breast cancer in patients with malignant axillary adenopathy. In these patients, MR imaging offers potential not only for cancer detection but also for staging the cancer within the breast, which may be useful for treatment planning.

Correlation of lesion appearance and histologic findings for the nodes of a breast MR imaging interpretation model

An interpretation model for evaluating magnetic resonance (MR) images of the breast was constructed that allowed differentiation of benign from malignant palpable or mammographically visible abnormalities. Architectural features define each node of the model. Investigation was subsequently made of the histologic findings in individuals within each node and of the frequency with which each histologic finding manifested as a particular architectural feature to determine whether nodal location and specific histologic findings are mutually predictive. The strongest associations were found between fibrocystic change and smooth masses, fibroadenoma and lobulated masses with nonenhancing internal septations, invasive ductal carcinoma (with or without ductal carcinoma in situ [DCIS]) and enhancing irregular or spiculated masses, invasive tubular carcinoma or radial scar and spiculated masses, medullary or colloid carcinoma and enhancing lobulated masses, invasive lobular carcinoma and the absence of a focal mass, DCIS and ductal enhancement, and DCIS (with or without invasive ductal carcinoma) and regional enhancement. Nodal location and histologic findings proved to be mutually predictive within the model; that is, the nodal location of MR imaging features within the model can be used to predict histologic findings and vice versa.

Domain swapping in G-protein coupled receptor dimers

Computer simulations were performed on models of the beta2-adrenergic receptor dimer, including 5,6-domain swapped dimers which have been proposed as the active, high affinity form (here the dimer interface lies between helices 5 and 6). The calculations suggest that the domain swapped dimer is a high energy structure in both the apo dimer and in the presence of propranolol. In the presence of agonist the energy of the domain swapped dimer is significantly lowered. Analysis of the dimer structure suggests that the agonist-induced conformational change optimizes the helix-helix interactions at the 5-6 interface. An antagonist on the other hand has little effect on these interactions. These observations are consistent with the hypothesis that the agonist functions by shifting the equilibrium in favour of the domain swapped dimer. Indirect support for the domain swapping hypothesis was obtained from the correlated mutations amongst the external residues of the known beta2-adrenergic receptors. These occur mainly at the 5-6 interface at precisely the locations predicted by the simulations; site-directed mutagenesis data in support of a functional role for these lipid-facing correlated residues is presented. The article includes a review of the experimental evidence for G-protein coupled receptor dimerization. Many other aspects of G-protein coupled receptor activation are discussed in terms of this domain swapping hypothesis

A new approach to docking in the beta 2-adrenergic receptor that exploits the domain structure of G-protein-coupled receptors

A novel technique for docking ligands to the beta 2-adrenergic receptor is described which exploits the domain structure of this class of receptors. The ligands (norepinephrine, an agonist; pindolol, a partial agonist; and propranolol, an antagonist) were docked into the receptor using the key conserved aspartate on helix 3 (D113) as an initial guide to the placement of the amino group and GRID maps (Goodford, P. J. J. Med. Chem, 1985, 28, 849) to identify the likely binding regions of the hydrophobic (and hydroxyl) moieties on the A domain (comprising of helices 1-5). The essence of the new approach involved pulling the B domain, which includes helices 6 and 7, away from the other domain by 5-7 A. During the subsequent minimization and molecular dynamics, the receptor ligand complex reformed to yield structures which were very well supported by site-directed mutagenesis data. In particular, the model predicted a number of important interactions between the antagonist and key residues on helix 7 (notably Leu311 and Asn312) which have not been described in many previous computer simulation studies. The justification for this new approach is discussed in terms of (a) phase space sampling and (b) mimicking the natural domain dynamics which may include domain swapping and dimerization to form a 5,6-domain-swapped dimer. The observed structural changes in the receptor when pindolol, the partial agonist, was docked were midway between those observed for propranolol and norepinephrine. These structural changes, particularly the changes in helix-helix interactions at the dimer interface, support the idea that the receptors have a very dynamic structure and may shed some light on the activation process. The receptor model used in these studies is well supported by experiment, including site-directed mutagenesis (helices 1-7), zinc binding studies (helices 2, 3, 5, and 6), the substituted cysteine accessibility method (helices 3, 5, and 7), and site-directed spin-labeling studies (helices 3-6).

Genetics and developmental psychopathology: 2. The main effects of genes and environment on behavioral problems in the Virginia Twin Study of Adolescent Behavioral Development

Little is known about the contribution of genetic and environmental factors to risk for juvenile psychopathology. The Virginia Twin Study of Adolescent Behavioral Development allows these contributions to be estimated. A population-based, unselected sample of 1412 Caucasian twin pairs aged 8-16 years was ascertained through Virginia schools. Assessment of the children involved semi-structured face-to-face interviews with both twins and both parents using the Child and Adolescent Psychiatric Assessment (CAPA). Self-report questionnaires were also completed by parents, children, and teachers. Measures assessed DSM-III-R symptoms of Attention Deficit Hyperactivity Disorder (ADHD). Conduct Disorder, Oppositional Defiant Disorder, Overanxious Disorder, Separation Anxiety, and Depressive Disorder. Factorially derived questionnaire scales were also extracted. Scores were normalized and standardized by age and sex. Maximum likelihood methods were used to estimate contributions of additive and nonadditive genetic effects, the shared and unique environment, and sibling imitation or contrast effects. Estimates were tested for heterogeneity over sexes. Generally, monozygotic (MZ) twins correlated more highly than dizygotic (DZ) twins, parental ratings more than child ratings, and questionnaire scales more highly than interviews. DZ correlations were very low for measures of ADHD and DZ variances were greater than MZ variances for these variables. Correlations sometimes differed between sexes but those for boy-girl pairs were usually similar to those for like-sex pairs. Most of the measures showed small to moderate additive genetic effects and moderate to large effects of the unique individual environment. Measures of ADHD and related constructs showed marked sibling contrast effects. Some measures of oppositional behavior and conduct disorder showed shared environmental effects. There were marked sex differences in the genetic contribution to separation anxiety, otherwise similar genetic effects appear to be expressed in boys and girls. Effects of rater biases on the genetic analysis are considered. The study supports a widespread influence of genetic factors on risk to adolescent psychopathology and suggests that the contribution of different types of social influence may vary consistently across domains of measurement.

Inclusion of conserved buried water molecules in the model structure of rat submaxillary kallikrein

A new approach to the molecular modelling of homologous serine proteases is adopted, by including a set of 21 buried waters known to be preserved in enzymes sharing the primary specificity of trypsin, in the homology modelling of rat submaxillary gland kallikrein. Buried waters--water molecules sequestered from bulk solvent within a protein matrix--appear to be integral conserved components of all serine proteases of known structure and should be incorporated into serine protease models built on the basis of sequence/structural homology to this family. The absence of such waters might induce errors in a force field simulation, favouring the formation of nonexistent hydrogen bonds and locally inaccurate structure. The kallikrein model refinement has led to the conclusion that an additional buried water should be added to the original rigid matrix of 21 conserved water molecules. The structurally preserved protein cavities of such waters validate the modelled structure.

Genetics and developmental psychopathology: 1. Phenotypic assessment in the Virginia Twin Study of Adolescent Behavioral Development

We introduce an overlapping cohort sequential longitudinal study of behavioral development and psychopathology in a representative sample of 1412 pairs of twins aged 8 through 16 years. Multiple phenotypic assessments involve a full psychiatric interview with each child and each parent, and supplementary parental, teacher, and child interview material and questionnaires. For the first wave of assessments, the numbers of reported DSM-III-R symptoms of Major Depressive Disorder (MDD), Separation Anxiety Disorder (SAD), Overanxious Disorder (OAD), Oppositional Defiant Disorder (ODD), Conduct Disorder (CD), and Attention Deficit Hyperactivity Disorder (ADHD), assessed through interviews, confirm patterns of age and sex trends found in other epidemiological samples, but underscore their dependence on whether the child or the parent is the informant. Correlations across domains for symptoms reported by the same informant are often as large as correlations across informants for the same domain of symptoms. Factor analyses of these symptom counts, taking account of informant view and unreliability of assessment, show the high degree of correlation between SAD and OAD, between MDD and OAD, and between CD and ODD. ADHD symptoms are relatively independent of the other domains, but show moderate correlations with CD, ODD, and MDD. Factorially derived dimensional questionnaire scales, based on child, parental, and teacher reports, show patterns of relationship to symptom counts consistent with both convergent and discriminant validity as indices of liability to clinical symptoms. Across informants, questionnaire scales provide as good a prediction of symptoms as do clinical interviews. Multitrait-multimethod confirmatory factor analysis reveals the patterns of relationship between symptoms of psychiatric disorder in children taking due account of informant and unique sources of variance. Gender differences are consistent within the correlated clusters of ODD/CD and MDD/SAD/OAD, although there are disorder-specific age trends. There are large informant-specific influences on the reporting of symptoms in clinical interviews. Dimensional questionnaire scales provide a useful source of additional information. In subsequent analyses of genetic and environmental etiology of childhood psychopathology we must expect that results may differ by informant and method of assessment. Multivariate and developmental analyses that explore the sources of these differences will shed new light on the relationship between genetic and environmentally influenced vulnerability and the manifestation of psychopathology in specific circumstances.

Diagnostic performance characteristics of architectural features revealed by high spatial-resolution MR imaging of the breast

OBJECTIVE

Our objective was twofold: to determine which architectural features revealed by high spatial-resolution MR imaging of the breast contribute to diagnostic accuracy and to evaluate the diagnostic performance characteristics of those architectural features.

MATERIALS AND METHODS

Eligible patients with suspicious mammographic or palpable findings or both underwent MR imaging. Ninety-three patients whose MR images revealed lesions that corresponded to the mammographically visible or palpable findings were included in the study. Patients were examined with sagittal T1-weighted spin-echo MR imaging, fat-saturated T2-weighted fast spin-echo MR imaging, and dynamically enhanced fat-saturated fast gradient-echo MR imaging. All patients underwent subsequent excisional biopsy or cyst aspiration. Lesions were identified initially by an experienced radiologist who was aware of the patient's clinical or mammographic information. Two radiologists who were unaware of the patients' histories and who had less experience in MR imaging of the breast then independently evaluated each lesion for the architectural-features and predicted each lesion's potential for malignancy.

RESULTS

Architectural features that were highly predictive of benign disease included smooth or lobulated borders (97-100%), the absence of mass enhancement (100%), and enhancement that was less than the enhancement of surrounding breast fibroglandular tissue (93-100%). Nonenhancing internal septations were specific for the diagnosis of fibroadenoma. Architectural features that were highly predictive of malignant disease included spiculated borders (76-88%) and peripheral rim enhancement in the presence of central lesion enhancement (79-92%).

CONCLUSION

Architectural features revealed by high spatial-resolution MR imaging of the breast can help distinguish benign from malignant disease.

Fibroadenomas: MR imaging appearances with radiologic-histopathologic correlation

PURPOSE

To identify histopathologic correlates for the varied magnetic resonance (MR) imaging appearances of fibroadenomas.

MATERIALS AND METHODS

Twenty-three fibroadenomas in 21 patients (aged 23-66 years) examined with gadolinium-enhanced MR imaging were graded for signal intensity on T2-weighted images, contrast material enhancement, shape, and internal septations and were correlated with histopathologic findings.

RESULTS

Fibroadenomas demonstrated high T2 signal intensity with enhancement (n = 11), low T2 signal intensity with enhancement (n = 3), or low T2 signal intensity without enhancement (n = 9). Low T2 signal intensity and lack of enhancement were associated with more sclerotic stroma and older patient age. Lesion shape was lobular, oval, or round in 19 of 23 fibroadenomas (83%). Internal septations were identified within nine of 14 enhancing fibroadenomas (64%) and appeared to correlate with collagenous bands at histopathologic analysis.

CONCLUSION

Fibroadenomas demonstrate marked histopathologic variability. The resultant variability in the MR appearance limits the ability to distinguish between benign and malignant masses on the basis of signal intensity and enhancement alone. Lobulation and internal septation, which appear to reflect intrinsic growth patterns of fibroadenomas, may provide a more reliable basis for distinction.

Breast MR imaging: interpretation model

PURPOSE

To develop an interpretation model based on architectural features of suspicious breast findings on magnetic resonance (MR) images.

MATERIALS AND METHODS

One hundred ninety-two patients with mammographically visible or palpable findings underwent T1- and fat-saturated T2-weighted spin-echo and contrast agent-enhanced fat-saturated gradient-echo MR imaging. Patients underwent subsequent excisional biopsy for histopathologic confirmation. An interpretation model was constructed by using 98 cases and was tested prospectively and expanded by using 94 different cases. Sensitivity, specificity, predictive values, and receiver operating characteristic curves were computed for all models.

RESULTS

Individual features with high predictive values were MR visibility, enhancement degree and pattern, focal mass border characteristics, and focal mass internal septations. Feature combinations with high negative predictive values for malignancy were absence of an MR-visible abnormality, focal masses with smooth borders, lobulated or irregular masses with nonenhancing internal septations, and focal masses with no (or minimal) enhancement. The validated- and revised-model performance characteristics were, respectively, as follows: sensitivity, 100% and 96%; specificity, 69% and 79%; positive predictive value, 75% and 76%; negative predictive value, 100% and 97%; and overall accuracy, 83% and 86%.

CONCLUSION

An interpretation model that incorporates breast MR architectural features can achieve high sensitivity and improve specificity for diagnosing breast cancer.

The genetics of children's oral reading performance

Measures of reading achievement and verbal ability have been shown to be heritable. Additionally, recent evidence has been suggestive of a major gene effect on reading disability and for problem reading in a sample of normal readers. We report on the etiology of individual differences in oral reading performance, the Slosson Oral Reading Test (SORT), for which biometrical analyses have not been reported in the literature previously. Oral reading performance was measured in a large population-based sample of twins of the Virginia Twin Study of Adolescent Behavioral Development. Biometrical analyses of the SORT suggested that, in both males and females, 69% of the phenotypic variation was due to heritable influences and 13% of the variation due to shared environmental effects. While the relative importance of genetic and environmental influences is equivalent for males and females, males showed greater phenotypic variability than females.

Sources of covariation among Mini-Mental State Examination scores, education, and cognitive abilities

An adoption/twin design was used to address issues concerning the relationship between education and Mini-Mental State Examination (MMSE) performance. Data on general cognitive abilities, education, and MMSE from 110 identical twin pairs and 177 fraternal pairs aged 50 through 88 were analyzed using multivariate quantitative genetic methods. Genetic influences account for 32% and 19% of the variation in MMSE for men and women, respectively. Furthermore, all of the genetic variation in MMSE is in common with genetic variation for cognitive abilities and education. Finally, correlations between education and MMSE (.21 and .16 for men and women, respectively), which were reduced to near zero when cognitive abilities were partialed out, are primarily attributable to genetic effects for cognitive abilities. These results support the hypothesis that the association between education and MMSE performance predominantly reflects genetically mediated cerebral capacity rather than test bias or health-endangering life styles in less educated individuals.

Genetics of educational attainment in Australian twins: sex differences and secular changes

The relative effects of genetic and environmental factors in producing individual differences in educational achievement are compared across women and men and over birth cohorts. In a large sample of Australian twin pairs, the heritability of self-reported educational attainment did not vary among women and men born before and after 1950. In a "psychometric" model of twin resemblance, based on separate self-reports in 1981 and 1989, genetic factors explained 57% of the stable variance in educational achievement, while environmental factors shared by twins accounted for 24% of the variance. Corrections for phenotypic assortative mating for educational level, however, suggested that estimated common-environmental effects could be entirely explained by the correlation between additive genetic values for mates. Taking this into account, heritability "true" educational attainment in Australia may be as high as 82% with the remaining variation being due to individual environments or experiences. Unlike previous studies in Scandinavian countries, results in Australia suggest that factors influencing educational success are comparable between women and men and for individuals born at different points during this century.

Models of spouse similarity: applications to fluid ability measured in twins and their spouses

Genetic influences have consistently been reported to be the principal explanation for resemblance among relatives for intelligence, with shared environmental effects playing a much smaller role. However, crucial to understanding the nature of environmental influences are the mechanisms of assortative mating. Phenotypic assortment, albeit widely assumed or modeled in biometrical analyses, may be less important than other assortment processes, such as social homogamy. Consequently, effects of shared environment may play a greater role than prior studies have suggested. The goal of this study was to resolve environmental and genetic influences on fluid ability based on alternative models of assortment by examining the similarity of monozygotic (MZ) and dizygotic (DZ) twins and their spouses. Raven's Progressive Matrices scores were available from a population-based Swedish sample of 138 twin kinships. The effects of both social homogamy and phenotypic assortment were tested simultaneously in each of two alternate assortment models. A factor/delta path model represented social homogamy as a common factor and phenotypic assortment as a delta path, while a delta/delta path model represented both social homogamy and phenotypic assortment as delta paths. Overall, the factor/delta path model was found to be superior. Results suggested that social homogamy completely explained spouse similarity; phenotypic assortment was not significant. The results of these analyses suggest the presence of shared environmental effects among twins and their spouses, which would have been underestimated if only phenotypic modeled phenotypic assortment may have underestimated the effects of environment.