A semiparametric model for between-subject attributes: Applications to beta-diversity of microbiome data

The human microbiome plays an important role in our health and identifying factors associated with microbiome composition provides insights into inherent disease mechanisms. By amplifying and sequencing the marker genes in high-throughput sequencing, with highly similar sequences binned together, we obtain operational taxonomic units (OTUs) profiles for each subject. Due to the high-dimensionality and nonnormality features of the OTUs, the measure of diversity is introduced as a summarization at the microbial community level, including the distance-based beta-diversity between individuals. Analyses of such between-subject attributes are not amenable to the predominant within-subject-based statistical paradigm, such as t-tests and linear regression. In this paper, we propose a new approach to model beta-diversity as a response within a regression setting by utilizing the functional response models (FRMs), a class of semiparametric models for between- as well as within-subject attributes. The new approach not only addresses limitations of current methods for beta-diversity with cross-sectional data, but also provides a premise for extending the approach to longitudinal and other clustered data in the future. The proposed approach is illustrated with both real and simulated data.

An Umbrella Converse for Data Exchange: Applied to Caching, Computing, and Shuffling

The problem of data exchange between multiple nodes with storage and communication capabilities models several current multi-user communication problems like Coded Caching, Data Shuffling, Coded Computing, etc. The goal in such problems is to design communication schemes which accomplish the desired data exchange between the nodes with the optimal (minimum) amount of communication load. In this work, we present a converse to such a general data exchange problem. The expression of the converse depends only on the number of bits to be moved between different subsets of nodes, and does not assume anything further specific about the parameters in the problem. Specific problem formulations, such as those in Coded Caching, Coded Data Shuffling, and Coded Distributed Computing, can be seen as instances of this generic data exchange problem. Applying our generic converse, we can efficiently recover known important converses in these formulations. Further, for a generic coded caching problem with heterogeneous cache sizes at the clients with or without a central server, we obtain a new general converse, which subsumes some existing results. Finally we relate a “centralized” version of our bound to the known generalized independence number bound in index coding and discuss our bound’s tightness in this context.

An Antiestrogenic Activity Score for tamoxifen and its metabolites is associated with breast cancer outcome

PURPOSE

Endoxifen concentrations have been associated with breast cancer recurrence in tamoxifen-treated patients. However, tamoxifen itself and other metabolites also show antiestrogenic anti-tumor activity. Therefore, the aim of this study was to develop a comprehensive Antiestrogenic Activity Score (AAS), which accounts for concentration and antiestrogenic activity of tamoxifen and three metabolites. An association between the AAS and recurrence-free survival was investigated and compared to a previously published threshold for endoxifen concentrations of 5.97 ng/mL.

PATIENTS AND METHODS

The antiestrogenic activities of tamoxifen, (Z)-endoxifen, (Z)-4-hydroxytamoxifen, and N-desmethyltamoxifen were determined in a cell proliferation assay. The AAS was determined by calculating the sum of each metabolite concentration multiplied by an IC₅₀ ratio, relative to tamoxifen. The AAS was calculated for 1370 patients with estrogen receptor alpha (ERα)-positive breast cancer. An association between AAS and recurrence was investigated using Cox regression and compared with the 5.97 ng/mL endoxifen threshold using concordance indices.

RESULTS

An AAS threshold of 1798 was associated with recurrence-free survival, hazard ratio (HR) 0.67 (95% confidence interval (CI) 0.47-0.96), bias corrected after bootstrap HR 0.69 (95% CI 0.48-0.99). The concordance indices for AAS and endoxifen did not significantly differ; however, using the AAS threshold instead of endoxifen led to different dose recommendations for 5.2% of the patients.

CONCLUSIONS

Endoxifen concentrations can serve as a proxy for the antiestrogenic effect of tamoxifen and metabolites. However, for the aggregate effect of tamoxifen and three metabolites, defined by an integrative algorithm, a trend towards improving treatment is seen and moreover, is significantly associated with breast cancer recurrence.

Abstract P3-09-01: Intermittent fasting in breast cancer risk and survivorship: Insight from the women's healthy eating and living study

Intermittent fasting (IF) regimens have gained widespread attention in recent years for their possible role in human health and disease risk. In mice, IF schedules that are aligned with sleep-wake cycles appear to positively influence metabolic processes related to cancer risk and may have direct effects on carcinogenesis; however the impact of these regimens on cancer risk in humans remain unclear. We examined associations between nighttime fasting duration (a form of IF aligned with sleep-wake cycles) and (1) biomarkers demonstrated to be associated with breast cancer prognosis; and (2) long-term clinical outcomes in a sample of breast cancer survivors from the Women's Healthy Eating and Living (WHEL) Study.

Dietary data were available for 3,061 non-diabetic women enrolled in the WHEL Study. Nighttime fasting duration was calculated using time-stamped 24-hour dietary recalls collected at the baseline, Year 1, and Year 4 study assessment periods. Approximately 3-4 dietary records were collected per subject at each assessment period, and these records were averaged to yield a single estimate of nighttime fasting duration per time point. Glycosylated hemoglobin (HbA1c) and C-reactive protein (CRP) levels were ascertained from blood specimen collected at baseline. Clinical outcomes recorded during the study follow-up include breast cancer events (recurrence or new primary) and mortality. Linear regression models examined the associations of nighttime fasting with baseline concentrations of HbA1c and CRP. Delayed-entry Cox proportional hazard models were used to assess the association between nighttime fasting duration, recorded at the baseline, Year 1, and Year 4 assessments, with clinical outcomes. These models used a counting process method to account for repeated measures. All models controlled for basic demographic factors, participant characteristics (BMI, comorbidity status, sleep duration), breast cancer characteristics (stage, grade, anti-estrogen use), and dietary variables (total calories, evening calories, eating frequency).

Women fasted an average of 12.5 hours per night (SD=1.6 hours). There were 520 new breast cancer events, and 569 deaths during study follow up. HbA1c level was significantly and inversely related to nighttime fasting duration. Each 2-hour increase in the nighttime fasting duration was associated with a 0.2-unit decrease in HbA1c (β=-0.21; p=0.03 with HbA1c expressed as mmol/mol), and there was no evidence of mediation or effect modification by participant characteristics, e.g., BMI. No associations were observed between nighttime fasting duration and CRP. In longitudinal models, women who fasted less than 13.1 hours per night (bottom two tertiles of nightly fasting distribution) had roughly a 50% higher hazard for experiencing a breast cancer event, compared to women who fasted at least 13.1 hours per night (HR: 1.46; 95%CI: 1.11-1.93; p<0.01). Nighttime fasting duration was not associated with mortality.

Findings suggest that increasing the length of the nighttime fasting interval could be a simple, feasible, and novel strategy to improve glucose control and reduce breast cancer risk. Randomized trials confirming the link between nighttime fasting duration and breast cancer risk are warranted.

Citation Format: Marinac CR, Neslon SH, Natarajan L, Sears DD, Breen CI, Pierce JP, Patterson RE. Intermittent fasting in breast cancer risk and survivorship: Insight from the women's healthy eating and living study. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-09-01.

Surface morphology of electrospun PLA fibers: mechanisms of pore formation

Interaction of relative humidity with solvent(s) is relatively more important in obtaining surface pores than solvent volatility and phase separation.

Abstract P2-09-31: Circulating Ang-2 Predicts Distant Breast Cancer Recurrence in WHEL Study

Background: The cytokine ,Angiopoietin-2 (Ang-2), is associated with breast cancer invasion and metastasis in preclinical models and in clinicopathologic studies of breast cancer. Anti-angiogenic therapy (bevacizumab plus chemotherapy) has anti-tumor activity in metastatic breast cancer patients. Circulating Ang-2 may serve as a biomarker for distant breast cancer recurrence. Multiple small studies suggest that circulating IL-6, a cytokine that promotes migration and invasion of breast cancer cells, may also predict recurrence. The Women's Healthy Eating and Living (WHEL) study has a unique data set with serial blood samples, some within 6 months of recurrence, which allowed a focused test of circulating factors and distant recurrence. Using a standard 30 cytokine array chosen because it included both Ang-2 and IL-6, we examined associations between cytokine markers and short-term distant breast cancer recurrence.

Methods: Fasting bloods were collected at 5 time points during the 6 year intervention of the WHEL study. There were 100 women who provided this sample within 6 months of diagnosis of recurrent metastatic cancer (oncologist confirmed). We tightly matched 100 non-recurrers from the main study who provided blood at the equivalent study time point. Matching variables included follow-up interval, age, clinical stage of the original tumor and enrollment site (WHEL had 7 sites). 30 chemo/cytokines were measured in each plasma sample using the Quantibody® Human Angiogenesis Array 2 (RayBiotech, Inc., Norcross, GA). Cytokine concentrations were log transformed. We used paired t-tests (P<0.20) to remove cytokines that did not differ between groups. Cox proportional hazard models were used to identify cytokines predictive of breast cancer recurrence after adjustment for covariates. Each Cox model was stratified by case/control pair number and contained one cytokine. The hazard ratio (95% Confidence Interval [CI]) was the measure of association per unit log transformed cytokine concentration. In further exploratory analysis, we applied a tree-based recursive partitioning method, Classification and Regression Trees (CART), which identifies high or low risk sub-group thresholds by sequentially choosing the most predictive marker. Results: The groups were successfully matched as only tumor grade met the criteria for inclusion as a covariate in the final models. Ang-2 and IL-6 differed between cases and controls in the paired t-test analyses, as did 3 other cytokines: RANTES, HB-EGF, and MCP-1. However, in the Cox proportional hazard models, only Ang-2 (HR=2.32; 95% C.I.= 1.16-4.66, p=0.02) reached statistical significance, although IL-6 was borderline significant (HR=1.52; 95% C.I.=0.94-2.47; p=0.09). Ang-2 was also the first marker chosen by the CART program and it identified 15 of the 200 in the study sample (8%) as protected (87% did not recur) and these were characterized with Ang-2 concentrations below 12.3 ng/ml. Discussion: This efficient nested case-control study tested whether circulating cytokines in the fasting blood predicts the onset of a distant recurrence within the next 6 months. This exploratory analysis identified Ang-2 as having prognostic value for metastatic breast cancer, but IL-6 was not a strong predictor in this study.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-09-31.

Hot flashes are associated with CYP2D6 genotype in breast cancer survivors taking tamoxifen

Abstract #6045

Background: We have previously shown that participants in the Women's Healthy Eating and Living (WHEL) study comparison group who reported hot flashes after breast cancer treatment had more favorable disease-free survival than women who did not report hot flashes. However, this was not the case in the intervention group. The polymorphic CYP450 enzyme CYP2D6 catalyzes the conversion of tamoxifen (TAM) to one of its key active metabolites, endoxifen. Some studies have suggested that certain genetic variants of CYP2D6 are associated with a decreased likelihood of hot flashes, reduced endoxifen levels and an increased risk of disease recurrence in women receiving adjuvant TAM therapy. This analysis was performed to estimate the association between CYP2D6 genotype and hot flashes in early stage breast cancer survivors who took adjuvant TAM in the WHEL study.
 Methods: The WHEL study was a randomized trial of a dietary intervention in breast cancer survivors, who enrolled in the study within 4 years of diagnosis from 1995-2000. Participants self-reported TAM use, hot flash severity and menopausal status at study entry. Clinical characteristics (tumor stage, estrogen receptor status, chemotherapy) were extracted from medical records. Blood samples were obtained by venipuncture, separated and stored at -80 deg. DNA was extracted from stored buffy coat and analyzed using the Roche AmpliChip CYP450 Test. Women were classified according to their predicted CYP2D6 phenotype as Extensive (EM), Heterozygous Extensive (Het EM), Intermediate (IM), Poor (PM), or Ultrarapid (UM) Metabolizers.
 Results: Overall, 1434 WHEL participants had verified estrogen receptor-positive stage I or II breast cancers and reported taking TAM at baseline for at least 4 months. A total of 1411 women were successfully genotyped and their CYP2D6 phenotypes were classified as follows: 468 EM (33.2%); 665 Het EM(47.1%), 164 IM (11.6%), 86 PM (6.1%) and 28 UM (2.0%). In univariate analyses, there was a significant difference among CYP2D6 genotype in relation to hot flashes reported at baseline: 79.8% of EMs, 76.3% of Het EMs, 80.1% of IMs, 63.9% of PMs, and 75% of UMs reported hot flashes (χ2= 11.3, p=0.02). After controlling for age, menopausal status, and time since diagnosis, the PM group was half as likely to report hot flashes as the referent EM group (OR= 0.46; 95% CI= 0.28-0.78; p=0.003). Additional analyses of serum endoxifen levels and associations with disease outcome are underway.
 Conclusion: In the WHEL study, women who were classified as Poor Metabolizers of TAM, based on their CYP2D6 genotype, were half as likely as Extensive Metabolizers to report experiencing hot flashes while receiving adjuvant TAM treatment for early stage breast cancer.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6045.

Physical health and cancer-free survival in women diagnosed with breast cancer

Abstract #1114

Background: A protective effect of physical activity (PA) after breast cancer diagnosis is not a consistent finding across studies. It is possible that a beneficial effect from higher PA levels may be limited to a sub-group defined by level of physical health (PH). We investigated the role of PA and PH in predicting breast cancer free survival.
 Methods: The Women's Healthy Eating and Living (WHEL) Study enrolled 3088 women within 4 years of early stage breast cancer diagnosis from 1995 to 2000. At study entry, participants completed the RAND-36 Health Survey that includes a physical health summary score comprised of physical functioning, general health, pain, and role limitations due to PH subscales. PA was assessed with a questionnaire developed for the Women's Health Initiative and validated for the WHEL Study. Additional breast cancer events (recurrence or new breast primary; n = 518) were queried semi-annually through June 2006 and confirmed by oncologist review of medical records. Multivariate Cox modeling was used to associate PA and PH with additional breast cancer events, adjusting for demographic, lifestyle, tumor, and treatment-related covariates.
 Results: In the unadjusted analysis, quartiles of PA were not related to additional breast cancer events, whereas the PH summary score was [Hazard ratios (HR) for quintiles (Q), Q1 (reference): Q2= 0.90, Q3 =0.69, Q4=0.55, and Q5=0.74; p-values = 0.45, 0.01, <0.0001, and 0.03 respectively]. For further analysis, we grouped the bottom two quintiles (“poor” PH) and the upper three quintiles (“adequate” PH). In the adjusted Cox model, poor PH was associated with a 42% higher risk of additional breast cancer events (HR: 1.42, 95% CI: 1.15, 1.74).
 We compared participants in poor versus adequate PH group. Those in the poor PH group were much more likely to report role limitations (91% vs. 17%) and bodily pain (44% vs. 4%). They were much more likely to be minimally physically active (<90 MET-minutes/week) (23% vs. 12%, p>0.0001) and obese (37% vs. 19%; p <0.0001). We included an interaction term into the Cox model using the binary PH measure and a binary PA measure (540 ≥ vs. < 540 MET-minutes/week, equivalent to 30 minutes moderate walking 6 days/week). Compared to those with adequate PH and higher PA, only those with poor PH and lower PA were at increased risk (HR 1.46, 95% CI: 1.15, 1.74).
 Among those in this higher risk subgroup (poor PH, lower PA), the majority indicated that they would not be limited a lot in walking a mile (79%) or climbing several flights of stairs (73%) and a substantial proportion indicated that they could undertake vigorous activity (37%).
 Discussion: Breast cancer survivors categorized as in poor PH had a 42% worse prognosis than those in adequate PH. This was particularly the case for those in poor PH who did less PA. This suggests that a motivational intervention to increase physical activity in this subgroup may improve their prognosis following breast cancer.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1114.

Identification of evolutionarily conserved promoter elements and amino acids required for function of the C. elegans beta-catenin homolog BAR-1

beta-catenins are conserved transcription factors regulated posttranslationally by Wnt signaling. bar-1 encodes a Caenorhabditis elegans beta-catenin acting in multiple Wnt-mediated processes, including cell fate specification by vulval precursor cells (VPCs) and migration of the Q(L) neuroblast progeny. We took two approaches to extend our knowledge of bar-1 function. First, we undertook a bar-1 promoter analysis using transcriptional GFP reporter fusions and found that bar-1 expression is regulated in specific cells at the transcriptional level. We identified promoter elements necessary for bar-1 expression in several cell types, including a 321-bp element sufficient for expression in ventral cord neurons (VCNs) and a 1.1-kb element sufficient for expression in the developing vulva and adult seam cells. Expression of bar-1 from the 321-bp element rescued the Uncoordinated (Unc) phenotype of bar-1 mutants, but not the vulval phenotype, suggesting that a Wnt pathway may act in ventral cord neurons to mediate proper locomotion. By comparison of the 1.1-kb element to homologous sequences from Caenorhabditis briggsae, we identified evolutionarily conserved sequences necessary for expression in vulval or seam cells. Second, we analyzed 24 mutations in bar-1 and identified several residues required for BAR-1 activity in C. elegans. By phylogenetic comparison, we found that most of these residues are conserved and may identify amino acids necessary for beta-catenin function in all species.

Transcriptional regulation of vascular endothelial cell responses to hypoxia by HIF-1

Hypoxia-inducible factor 1 (HIF-1) activates transcription of genes encoding angiogenic growth factors, which are secreted by hypoxic cells and stimulate endothelial cells, leading to angiogenesis. To determine whether HIF-1 also mediates cell-autonomous responses to hypoxia, we have compared gene expression profiles in arterial endothelial cells cultured under nonhypoxic versus hypoxic conditions and in nonhypoxic cells infected with adenovirus encoding beta-galactosidase versus a constitutively active form of HIF-1alpha (AdCA5). There were 245 gene probes that showed at least 1.5-fold increase in expression in response to hypoxia and in response to AdCA5; 325 gene probes showed at least 1.5-fold decrease in expression in response to hypoxia and in response to AdCA5. The largest category of genes down-regulated by both hypoxia and AdCA5 encoded proteins involved in cell growth/proliferation. Many genes up-regulated by both hypoxia and AdCA5 encoded cytokines/growth factors, receptors, and other signaling proteins. Transcription factors accounted for the largest group of HIF-1-regulated genes, indicating that HIF-1 controls a network of transcriptional responses to hypoxia in endothelial cells. Infection of endothelial cells with AdCA5 under nonhypoxic conditions was sufficient to induce increased basement membrane invasion and tube formation similar to the responses induced by hypoxia, indicating that HIF-1 mediates cell-autonomous activation of endothelial cells.

Correlates of obesity in postmenopausal women with breast cancer: comparison of genetic, demographic, disease-related, life history and dietary factors

BACKGROUND

Obesity in women has been associated with a variety of factors, including genetic predisposition, social class, early age at menarche, exercise, alcohol consumption and diet. Obesity is a risk factor for the occurrence and the recurrence of breast cancer in postmenopausal women, perhaps because of increased exposure to estrogen, insulin and insulin-like growth factors (IGFs). The progesterone receptor (PR) and the steroid hormone receptor coactivator pCIP/ACTR/AIB1/TRAM1/RAC3 (AIB1) are hypothesized to mediate signaling crosstalk between these hormonal pathways. Polymorphisms in both genes have been described and their association with breast cancer risk reported. If genetic factors contribute to obesity, and the PR and AIB1 genes influence estrogenic, insulin and IGF pathways, then genetic patterns resulting from PR and AIB1 polymorphisms may be associated with obesity in postmenopausal women.

OBJECTIVE

We compared the PR and AIB1 genotypes of postmenopausal women with breast cancer with demographic, disease-related, reproductive, lifestyle and dietary variables in terms of the strength of their relationship with obesity (BMI> or =30 kg/m2).

SUBJECTS

A total of 301 postmenopausal women previously diagnosed with Stage I, II or IIIA breast cancer, who are enrolled in the Women's Healthy Eating and Living (WHEL) study (age: 34.5-70.8 y, BMI: 17.8-54.6 kg/m2).

MEASUREMENTS

The PR polymorphism PROGINS was identified by PCR. The length of the AIB1 polyglutamine repeat was determined by PCR and nondenaturing gel electrophoresis or DNA sequencing. BMI was obtained at the baseline clinic visit upon entry into the WHEL study. Information about date of diagnosis, stage of disease, tumor hormone receptor status and adjuvant treatment received were obtained from medical records. Reproductive, menstrual history, demographic, family history of cancer, smoking history and exercise frequency and intensity information were obtained from questionnaires. Dietary and alcohol intake data came from four 24-h telephone recalls of food intake obtained at the study entry.

RESULTS

The combined inheritance of PROGINS A1/A1 and AIB1 28/29, 28/30, 28/31, 29/29 or 29/30 (AIB1 LG) genotypes (adjusted odds ratio (OR)=2.22 (95% confidence interval 1.25-3.93)) and early age at menarche (<12 y) (adjusted OR=2.34 (1.12-4.86)) were each associated with the risk for obesity. Current use of tamoxifen (adjusted OR=0.49 (0.28-0.87)) and an alcohol intake > or =10 g/day (adjusted OR=0.28 (0.11-0.77)) were inversely associated with BMI > or =30 kg/m2.

CONCLUSION

Early age at menarche and a PROGINS A1/A1+AIB1 LG genetic pattern had comparable levels of association with obesity in this cross-sectional sample of postmenopausal women with breast cancer. Since this was a cross-sectional rather than a case-control design, the association between PROGINS and AIB1 genotype and obesity found in this sample should be considered preliminary, and must be re-evaluated with a new and larger sample.

Switchable orthorhombic F photonic crystals formed by holographic polymerization-induced phase separation of liquid crystal

Electrically switchable photonic crystals are simply and rapidly formed by holographic polymerization-induced phase separation of liquid crystal from a monomer-liquid crystal mixture. We report the fabrication and electro-optical properties of liquid-crystal-filled polymer photonic crystals of orthorhombic F symmetry. Inverse opal and fcc structures can also be obtained. The crystals exhibit electrically switchable Bragg diffraction at ~8-10 V/microm with crystal structure in good agreement with theoretical expectations. These photonic crystals compare favorably with liquid-crystal-imbibed colloidal crystal arrays.

A prospective study of stress among women undergoing in vitro fertilization or gamete intrafallopian transfer

OBJECTIVE

To evaluate whether baseline or procedural stress during in vitro fertilization (IVF) or gamete intrafallopian transfer (GIFT) affects pregnancy or live birth delivery rates.

DESIGN

Prospective study.

SETTING

Seven clinics in Southern California between 1993 and 1998.

PATIENT(S)

One hundred and fifty-one women completed two questionnaires.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The number of oocytes aspirated and fertilized, the number of embryos transferred, the achievement of a pregnancy, live birth delivery, and infant outcomes.

RESULT(S)

Positive-affect negative-affect score at baseline negatively influenced the number of oocytes retrieved and embryos transferred. A higher expectation of pregnancy was associated with greater numbers of oocytes fertilized and embryos transferred. At baseline, the risk of no live birth was 93% lower for women who had the highest positive-affect score compared to those with the lowest score. Furthermore, the score on the Infertility Reaction Scale was related to negative outcomes in live birth delivery, infant birth weight, and multiple births. During the time of the procedure, the PANAS and Bipolar Profile of Moods States results were related to the number of oocytes fertilized and embryos transferred; stress did not affect pregnancy or delivery.

CONCLUSION(S)

Baseline (acute and chronic) stress affected biologic end points (i.e., number of oocytes retrieved and fertilized), as well as pregnancy, live birth delivery, birth weight, and multiple gestations, whereas (procedural) stress only influenced biologic end points.

The divergent Caenorhabditis elegans beta-catenin proteins BAR-1, WRM-1 and HMP-2 make distinct protein interactions but retain functional redundancy in vivo

beta-Catenins function both in cell adhesion as part of the cadherin/catenin complex and in Wnt signal transduction as transcription factors. Vertebrates express two related proteins, beta-catenin and plakoglobin, while Drosophila has a single family member, Armadillo. Caenorhabditis elegans expresses three beta-catenin-related proteins, BAR-1, HMP-2, and WRM-1, which are quite diverged in sequence from each other and other beta-catenins. While BAR-1 and WRM-1 are known to act in Wnt-mediated processes, and HMP-2 acts in a complex with cadherin/alpha-catenin homologs, it is unclear whether all three proteins retain the other functions of beta-catenin. Here we show that BAR-1, like vertebrate beta-catenin, has redundant transcription activation domains in its amino- and carboxyl-terminal regions but that HMP-2 and WRM-1 also possess the ability to activate transcription. We show via yeast two-hybrid analysis that these three proteins display distinct patterns of protein interactions. Surprisingly, we find that both WRM-1 and HMP-2 can substitute for BAR-1 in C. elegans when expressed from the bar-1 promoter. Therefore, although their mutant phenotypes and protein interaction patterns strongly suggest that the functions of beta-catenin in other species have been segregated among three diverged proteins in C. elegans, these proteins still retain sufficient similarity to display functional redundancy in vivo.

Effects of female and male smoking on success rates of IVF and gamete intra-Fallopian transfer

BACKGROUND

Smoking by both male and female partners may play a significant role in the success rates of assisted reproductive technologies. The objective of this 5-year prospective study was to investigate the influence of cigarette smoking by the wife, husband, and couple at various time points (e.g. lifetime, week prior, or during the procedures) on different biological parameters of IVF and gamete intra-Fallopian transfer (GIFT).

METHODS AND RESULTS

A total of 221 couples, aged >20 years, of Caucasian, Black, Asian or Hispanic descent were recruited from seven infertility clinics located in Southern California. Couples (i.e. either female or male or both) who ever smoked compared with non-smokers, had adjusted relative risks (RR) of 2.41 (95% CI 1.07-5.45, P = 0.03) of not achieving a pregnancy, and 3.76 (95% CI 1.40-10.03, P < 0.01) of not having a live birth delivery, while adjusting for potential confounders. For couples who smoked for >5 years, there was an adjusted RR = 4.27 of not achieving a pregnancy (95% CI l.53-11.97, P = 0.01). The number of oocytes retrieved decreased by 40% for couples (smokers, n = 6) and by 46% for men who smoked during the week of the visit for IVF or GIFT. Women who smoked in their lifetime had adjusted risks of 2.71 of not achieving a pregnancy (95% CI 1.37-5.35, P < 0.01), and 2.51 (95% CI 1.11-5.67, P < 0.03) of not having a live birth delivery.

CONCLUSIONS

There is compelling evidence that couples should be made aware that smoking years before undergoing IVF and GIFT can impact treatment outcome. This study may also provide insight into the timing and effects of male and female smoking on natural reproduction.

Evaluation of gentamicin pharmacokinetics during peritoneal dialysis

The pharmacokinetics of gentamicin were examined in two functionally anephric patients undergoing peritoneal dialysis (PD). Peritoneal dialysis effectively decreased the gentamicin half-life (t1/2 beta) by 73 and 78% while increasing total body clearance [QB(ml/min/kg] of gentamicin 4.3- and 3.4-fold. The appreciable variability in gentamicin pharmacokinetics among renal failure patients being peritoneally dialyzed may necessitate dosage adjustments based on rapid and accurate measurement of serum gentamicin concentrations.