Insulin resistance and chronic kidney disease progression, cardiovascular events, and death: findings from the chronic renal insufficiency cohort study

BACKGROUND

Insulin resistance contributes to the metabolic syndrome, which is associated with the development of kidney disease. However, it is unclear if insulin resistance independently contributes to an increased risk of chronic kidney disease (CKD) progression or CKD complications. Additionally, predisposing factors responsible for insulin resistance in the absence of diabetes in CKD are not well described. This study aimed to describe factors associated with insulin resistance and characterize the relationship of insulin resistance to CKD progression, cardiovascular events and death among a cohort of non-diabetics with CKD.

METHODS

Data was utilized from Chronic Renal Insufficiency Cohort Study participants without diabetes (N = 1883). Linear regression was used to assess associations with insulin resistance, defined using the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR). The relationship of HOMA-IR, fasting glucose, hemoglobin A1c (HbA1c), and C-peptide with CKD progression, cardiovascular events, and all-cause mortality was examined with Cox proportional hazards models.

RESULTS

Novel positive associations with HOMA-IR included serum albumin, uric acid, and hemoglobin A1c. After adjustment, HOMA-IR was not associated with CKD progression, cardiovascular events, or all-cause mortality. There was a notable positive association of one standard deviation increase in HbA1c with the cardiovascular endpoint (HR 1.16, 95% CI: 1.00-1.34).

CONCLUSION

We describe potential determinants of HOMA-IR among a cohort of non-diabetics with mild-moderate CKD. HOMA-IR was not associated with renal or cardiovascular events, or all-cause mortality, which adds to the growing literature describing an inconsistent relationship of insulin resistance with CKD-related outcomes.

Incident Type 2 Diabetes Among Individuals With CKD: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study

RATIONALE & OBJECTIVE

Few studies have examined incident type 2 diabetes mellitus (T2DM) in chronic kidney disease (CKD). Our objective was to examine rates of and risk factors for T2DM in CKD, using several alternative measures of glycemic control.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

1,713 participants with reduced glomerular filtration rates and without diabetes at baseline, enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study.

PREDICTORS

Measures of kidney function and damage, fasting blood glucose, hemoglobin A1c (HbA1c), HOMA-IR (homeostatic model assessment of insulin resistance), demographics, family history of diabetes mellitus (DM), smoking status, medication use, systolic blood pressure, triglyceride level, high-density lipoprotein cholesterol level, body mass index, and physical activity.

OUTCOME

Incident T2DM (defined as fasting blood glucose ≥ 126mg/dL or prescription of insulin or oral hypoglycemic agents).

ANALYTICAL APPROACH

Concordance between fasting blood glucose and HbA1c levels was assessed using κ. Cause-specific hazards modeling, treating death and end-stage kidney disease as competing events, was used to predict incident T2DM.

RESULTS

Overall T2DM incidence rate was 17.81 cases/1,000 person-years. Concordance between fasting blood glucose and HbA1c levels was low (κ for categorical versions of fasting blood glucose and HbA1c = 13%). Unadjusted associations of measures of kidney function and damage with incident T2DM were nonsignificant (P ≥ 0.4). In multivariable models, T2DM was significantly associated with fasting blood glucose level (P = 0.002) and family history of DM (P = 0.03). The adjusted association of HOMA-IR with T2DM was comparable to that of fasting blood glucose level; the association of HbA1c level was nonsignificant (P ≥ 0.1). Harrell's C for the models ranged from 0.62 to 0.68.

LIMITATIONS

Limited number of outcome events; predictors limited to measures taken at baseline.

CONCLUSIONS

The T2DM incidence rate among individuals with CKD is markedly higher than in the general population, supporting the need for greater vigilance in this population. Measures of glycemic control and family history of DM were independently associated with incident T2DM.

Health Behaviors in Younger and Older Adults With CKD: Results From the CRIC Study

INTRODUCTION

A cornerstone of kidney disease management is participation in guideline-recommended health behaviors. However, the relationship of these health behaviors with outcomes, and the identification of barriers to health behavior engagement, have not been described among younger and older adults with chronic kidney disease.

METHODS

Data from a cohort study of 5499 individuals with chronic kidney disease was used to identify health behavior patterns with latent class analysis stratified by age <65 and ≥65 years. Cox models, stratified by diabetes, assessed the association of health behavior patterns with chronic kidney disease (CKD) progression, atherosclerotic events, and death. Logistic regression was used to assess for barriers to health behavior engagement.

RESULTS

Three health behavior patterns were identified: 1 "healthy" pattern, and 2 "less healthy" patterns comprising 1 pattern with more obesity and sedentary activity and 1 with more smoking and less obesity. Less healthy patterns were associated with an increased hazard of poor outcomes. Among participants <65 years of age, the less healthy patterns (vs. healthy pattern) was associated with an increased hazard of death in diabetic individuals (hazard ratio [HR] = 2.17, 95% confidence interval [CI] = 1.09-4.29; and HR = 2.50, 95% CI = 1.39-4.50) and cardiovascular events among nondiabetic individuals (HR = 1.49, 95% CI = 1.04-2.43; and HR = 2.97, 95% CI = 1.49-5.90). Individuals with the more obese/sedentary pattern had an increased risk of CKD progression in those who were diabetic (HR = 1.34, 95% CI = 1.13-1.59). Among older adults, the less healthy patterns were associated with increased risk of death (HR = 2.97, 95% CI = 1.43-6.19; and HR = 3.47, 95% CI = 1.48-8.11) in those who were nondiabetic. Potential barriers to recommended health behaviors include lower health literacy and self-efficacy.

CONCLUSION

Identifying health behavior patterns and barriers may help target high-risk groups for strategies to increase participation in health behaviors.

Patient Experience with Primary Care Physician and Risk for Hospitalization in Hispanics with CKD

BACKGROUND AND OBJECTIVES

In the general population, the quality of the patient experience with their primary care physician may influence health outcomes but this has not been evaluated in CKD. This is relevant for the growing Hispanic CKD population, which potentially faces challenges to the quality of the patient experience related to language or cultural factors. We evaluated the association between the patient experience with their primary care physician and outcomes in Hispanics with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This prospective observational study included 252 English- and Spanish-speaking Hispanics with entry eGFR of 20-70 ml/min per 1.73 m2, enrolled in the Hispanic Chronic Renal Insufficiency Cohort study between 2005 and 2008. Patient experience with their primary care physician was assessed by the Ambulatory Care Experiences Survey subscales: communication quality, whole-person orientation, health promotion, interpersonal treatment, and trust. Poisson and proportional hazards models were used to assess the association between the patient experience and outcomes, which included hospitalization, ESKD, and all-cause death.

RESULTS

Participants had a mean age of 56 years, 38% were women, 80% were primary Spanish speakers, and had a mean eGFR of 38 ml/min per 1.73 m2. Over 4.8 years (median) follow-up, there were 619 hospitalizations, 103 ESKD events, and 56 deaths. As compared with higher subscale scores, lower scores on four of the five subscales were associated with a higher adjusted rate ratio (RR) for all-cause hospitalization (communication quality: RR, 1.54; 95% confidence interval [95% CI], 1.25 to 1.90; health promotion: RR, 1.31; 95% CI, 1.05 to 1.62; interpersonal treatment: RR, 1.50; 95% CI, 1.22 to 1.85; and trust: RR, 1.57; 95% CI, 1.27 to 1.93). There was no significant association of subscales with incident ESKD or all-cause death.

CONCLUSIONS

Lower perceived quality of the patient experience with their primary care physician was associated with a higher risk of hospitalization.

CKD Self-management: Phenotypes and Associations With Clinical Outcomes

BACKGROUND

To slow chronic kidney disease (CKD) progression and its complications, patients need to engage in self-management behaviors. The objective of this study was to classify CKD self-management behaviors into phenotypes and assess the association of these phenotypes with clinical outcomes.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

Adults with mild to moderate CKD enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study. 3,939 participants in the CRIC Study recruited between 2003 and 2008 served as the derivation cohort and 1,560 participants recruited between 2013 and 2015 served as the validation cohort.

PREDICTORS

CKD self-management behavior phenotypes.

OUTCOMES

CKD progression, atherosclerotic events, heart failure events, death from any cause.

MEASUREMENTS

Latent class analysis stratified by diabetes was used to identify CKD self-management phenotypes based on measures of body mass index, diet, physical activity, blood pressure, smoking status, and hemoglobin A1c concentration (if diabetic); Cox proportional hazards models.

RESULTS

3 identified phenotypes varied according to the extent of implementation of recommended CKD self-management behaviors: phenotype I characterized study participants with the most recommended behaviors; phenotype II, participants with a mixture of recommended and not recommended behaviors; and phenotype III, participants with minimal recommended behaviors. In multivariable-adjusted models for those with and without diabetes, phenotype III was strongly associated with CKD progression (HRs of 1.82 and 1.49), death (HRs of 1.95 and 4.14), and atherosclerotic events (HRs of 2.54 and 1.90; each P < 0.05). Phenotype II was associated with atherosclerotic events and death among those with and without diabetes.

LIMITATIONS

No consensus definition of CKD self-management; limited to baseline behavior data.

CONCLUSIONS

There are potentially 3 CKD self-management behavior phenotypes that distinguish risk for clinical outcomes. These phenotypes may inform the development of studies and guidelines regarding optimal self-management.

Abstract PD5-04: Ki67 changes and PEPI score in the LORELEI trial: A phase II randomized, double-blind study of neoadjuvant letrozole plus taselisib versus letrozole plus placebo in postmenopausal women with ER-positive/HER2-negative early-stage breast cancer

Background: Taselisib is an oral, potent, selective inhibitor of Class I PI3-kinase (PI3K) alpha, gamma, and delta isoforms with enhanced activity against PIK3CA mutant cancer cells. LORELEI trial demonstrated a significant improvement in ORR (objective response rate) centrally assessed by MRI with neoadjuvant taselisib plus letrozole compared to letrozole plus placebo in all randomized patients as well as in the PIK3CA mutant cohort (Saura et al, ESMO 2017).

Methods: 334 postmenopausal women with newly diagnosed ER+/HER2-, untreated, Stage I-III operable breast cancer and evaluable tumor tissue for PIK3CA genotyping were randomized (1:1) to receive daily letrozole (2.5 mg) with either taselisib (4 mg on a 5 days on/ 2 days off schedule) or placebo for 16 weeks, followed by surgery. Tumor tissue collection was performed at baseline, week 3 (W3) and at surgery. Secondary objectives included, but were not restricted to, ORR assessed by MRI in patients with PIK3CA wild type (WT) tumors, ORR using alternative methods of tumor assessment (ultrasound, mammogram and clinical breast exam) in all patients and patients with PIK3CA mutant and WT tumors, central assessment of Ki67 at different timepoints (baseline, W3 and surgery), and the centrally derived PEPI score. Central Ki67 was assessed by two independent readers blinded to treatment arms and PIK3CA status (Vall D'Hebron Institute of Oncology, Barcelona).

Results: ORR by centrally assessed MRI was similar in the two treatment arms in patients with PIK3CA WT tumors (45.7 vs 40.4% for taselisib and placebo, respectively). ORR assessed by breast US was also significantly higher with taselisib compared to placebo in all randomized patients and in the PIK3CA mutant cohort. The highest concordance rate between MRI and other imaging modalities was found with breast ultrasound (53.7%). Centrally assessed Ki67 changes are reported in Table 1. Ki67 values decreased from baseline to W3 and from baseline to surgery in both treatment arms. No significant differences in the decrease of Ki67 values between treatment arms were detected. Unplanned analysis of Complete Cell Cycle Arrest (CCCA) at W3 was numerically higher with taselisib than with placebo in all randomized patients (49.6% vs 38.5%) and in the PIK3CA mutant cohort (60.9% vs 47.5%). Due to the variability in timing between the last dose of taselisib (median time 11 days; interquartile range 6-16 days) and tissue collection at surgery, considering the half-life of taselisib of approximately 40 hours, centrally derived PEPI score is not interpretable.

Ki67 proportional changes, %Taselisib + letrozolePlacebo + letrozoleBaseline to W3All patients-83.8-80.4PIK3CA mutant-84.5-79.1PIK3CA WT-82.8-81.1Baseline to surgeryAll patients-75.6-80.5PIK3CA mutant-71.9-79.9PIK3CA WT-78.2-81.2

Conclusion: Among the investigated alternative methods for assessing ORR, breast ultrasound performed similar to MRI. Decrease in the Ki67 values from baseline to W3 and to surgery were observed in both treatment arms. The time interval between taselisib cessation and tissue collection at surgery are being further investigated.

Clinical trial information: NCT02273973

Citation Format: de Azambuja E, Saura C, Nuciforo P, Frantal S, Oliveira M, Zardavas D, Jallitsch-Halper A, de la Pena L, Dubsky P, Lombard JM, Vuylsteke P, Castaneda Altamirano C, Sanchez C, Ballestrero A, Colleoni M, Santos Borges G, Ciruelos E, Bardia A, Fornier M, Boer K, Wilson TR, Stout TJ, Hsu JY, Shi Y, Piccart M, Baselga J, Gnant M. Ki67 changes and PEPI score in the LORELEI trial: A phase II randomized, double-blind study of neoadjuvant letrozole plus taselisib versus letrozole plus placebo in postmenopausal women with ER-positive/HER2-negative early-stage breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD5-04.

Estimation of discrete survival function for error-prone diagnostic tests

The product limit or Kaplan-Meier (KM) estimator is commonly used to estimate the survival function in the presence of incomplete time to event. Application of this method assumes inherently that the occurrence of an event is known with certainty. However, the clinical diagnosis of an event is often subject to misclassification due to assay error or adjudication error, by which the event is assessed with some uncertainty. In the presence of such errors, the true distribution of the time to first event would not be estimated accurately using the KM method. We develop a method to estimate the true survival distribution by incorporating negative predictive values and positive predictive values, into a KM-like method of estimation. This allows us to quantify the bias in the KM survival estimates due to the presence of misclassified events in the observed data. We present an unbiased estimator of the true survival function and its variance. Asymptotic properties of the proposed estimators are provided, and these properties are examined through simulations. We demonstrate our methods using data from the Viral Resistance to Antiviral Therapy of Hepatitis C study.

Statistical Methods for Modeling Time-Updated Exposures in Cohort Studies of Chronic Kidney Disease

When estimating the effect of an exposure on a time-to-event type of outcome, one can focus on the baseline exposure or the time-updated exposures. Cox regression models can be used in both situations. When time-dependent confounding exists, the Cox model with time-updated covariates may produce biased effect estimates. Marginal structural models, estimated through inverse-probability weighting, were developed to appropriately adjust for time-dependent confounding. We review the concept of time-dependent confounding and illustrate the process of inverse-probability weighting. We fit a marginal structural model to estimate the effect of time-updated systolic BP on the time to renal events such as ESRD in the Chronic Renal Insufficiency Cohort. We compare the Cox regression model and the marginal structural model on several attributes (effects estimated, result interpretation, and assumptions) and give recommendations for when to use each method.

Analytic Considerations for Repeated Measures of eGFR in Cohort Studies of CKD

Repeated measures of various biomarkers provide opportunities for us to enhance understanding of many important clinical aspects of CKD, including patterns of disease progression, rates of kidney function decline under different risk factors, and the degree of heterogeneity in disease manifestations across patients. However, because of unique features, such as correlations across visits and time dependency, these data must be appropriately handled using longitudinal data analysis methods. We provide a general overview of the characteristics of data collected in cohort studies and compare appropriate statistical methods for the analysis of longitudinal exposures and outcomes. We use examples from the Chronic Renal Insufficiency Cohort Study to illustrate these methods. More specifically, we model longitudinal kidney outcomes over annual clinical visits and assess the association with both baseline and longitudinal risk factors.

Statistical Methods for Cohort Studies of CKD: Prediction Modeling

Prediction models are often developed in and applied to CKD populations. These models can be used to inform patients and clinicians about the potential risks of disease development or progression. With increasing availability of large datasets from CKD cohorts, there is opportunity to develop better prediction models that will lead to more informed treatment decisions. It is important that prediction modeling be done using appropriate statistical methods to achieve the highest accuracy, while avoiding overfitting and poor calibration. In this paper, we review prediction modeling methods in general from model building to assessing model performance as well as the application to new patient populations. Throughout, the methods are illustrated using data from the Chronic Renal Insufficiency Cohort Study.

Development of a Clinically Actionable Incisional Hernia Risk Model after Colectomy Using the Healthcare Cost and Utilization Project

BACKGROUND

Incisional hernia remains a persistent and burdensome complication after colectomy. Through individualized risk-assessment and prediction models, we aimed to improve preoperative risk counseling for patients undergoing colectomy; identify modifiable preoperative risk factors; and encourage the use of evidence-based risk-prediction instruments in the clinical setting.

STUDY DESIGN

A retrospective review of the Healthcare Cost and Utilization Project data was conducted for all patients undergoing either open or laparoscopic colectomy as identified through the state inpatient databases of California, Florida, and New York in 2009. Incidence of incisional hernia repair was collected from both the state inpatient databases and the state ambulatory surgery and services databases in the 3 states between index surgery and 2011. Hernia risk was calculated with multivariable hierarchical logistic regression modeling and validated using bootstrapping techniques. Exclusion criteria included concurrent hernia, metastasis, mortality, and age younger than 18 years. Inflation-adjusted expenditure estimates were calculated.

RESULTS

Overall, 30,741 patients underwent colectomy, one-third of these procedures performed laparoscopically. Incisional hernia repair was performed in 2,563 patients (8.3%) (27-month follow-up). Fourteen significant risk factors were identified, including open surgery (odds ratio = 1.49; p < 0.0001), obesity (odds ratio = 1.49; p < 0.0001), and alcohol abuse (odds ratio = 1.39; p = 0.010). Extreme-risk patients experienced the highest incidence of incisional hernia (19.8%) vs low-risk patients (3.9%) (C-statistic = 0.67).

CONCLUSIONS

We present a clinically actionable model of incisional hernia using all-payer claims after colectomy. The data presented can structure preoperative risk counseling, identify modifiable patient-specific risk factors, and advance the field of risk prediction using claims data.

Lead-Time Bias and Interhospital Transfer after Injury: Trauma Center Admission Vital Signs Underpredict Mortality in Transferred Trauma Patients

BACKGROUND

Admission physiology predicts mortality after injury, but may be improved by resuscitation before transfer. This phenomenon, which has been termed lead-time bias, may lead to underprediction of mortality in transferred patients and inaccurate benchmarking in centers receiving large numbers of transfer patients. We sought to determine the impact of using vital signs on arrival at the referring center vs on arrival at the trauma center in mortality prediction models for transferred trauma patients.

STUDY DESIGN

We performed a retrospective cohort study using a state-wide trauma registry including all patients age 16 years or older, with Abbreviated Injury Scale scores ≥ 3, admitted to level I and II trauma centers in Pennsylvania, from 2011 to 2014. The primary outcomes measure was the risk-adjusted association between mortality and interhospital transfer (IHT) when adjusting for physiology (as measured by Revised Trauma Score [RTS]) using the referring hospital arrival vital signs (model 1) compared with trauma center arrival vital signs (model 2).

RESULTS

After adjusting for patient and injury factors, IHT was associated with reduced mortality (odds ratio [OR] 0.85; 95% CI 0.77 to 0.93) using the RTS from trauma center admission, but with increased mortality (OR 1.15; 95% CI 1.05 to 1.27) using RTS from the referring hospital. The greater the number of transfer patients seen by a center, the greater the difference in center-level mortality predicted by the 2 models (β -0.044; 95% CI -0.044 to -0.0043; p ≤ 0.001).

CONCLUSIONS

Trauma center vital signs underestimate mortality in transfer patients and may lead to incorrect estimates of expected mortality. Where possible, benchmarking efforts should use referring hospital vital signs to risk-adjust IHT patients.

Evaluating the impact of the laborist model of obstetric care on maternal and neonatal outcomes

BACKGROUND

The laborist model of obstetric care represents a change in care delivery with the potential of improving maternal and neonatal outcomes.

OBJECTIVE

We evaluated the effectiveness of the laborist model of care compared to the traditional model of obstetric care using specific maternal and neonatal outcome measures.

STUDY DESIGN

This is a population cohort study with laborist and nonlaborist hospitals matched 1:2 on delivery volume, geography, teaching status, and neonatal intensive care unit level using data from the National Perinatal Information Center/Quality Analytic Services database. A before-and-after study design with an untreated comparison group analyzed with the method of difference-in-differences was used to examine the impact of laborists on maternal and neonatal outcome measures within the 3 years after implementing the laborist system, after adjusting for secular trends, sociodemographic factors, and maternal medical conditions. The final outcome measures evaluated included cesarean delivery, chorioamnionitis, induction of labor, preterm birth, prolonged length of stay, Apgar at 5 minutes of <7, birth asphyxia, birth injury, birth trauma, and neonatal death.

RESULTS

We studied nearly 550,000 women from 24 hospitals (8 laborist and 16 nonlaborist hospitals) from 1998 through 2011. Implementation of laborists was associated with fewer labor inductions (adjusted odds ratio, 0.85; 95% confidence interval, 0.71-0.99) and decreased rate of preterm birth (adjusted odds ratio, 0.83; 95% confidence interval, 0.72-0.96) after controlling for confounders. Laborists did not impact the cesarean delivery rate, chorioamnionitis, or prolonged length of stay.

CONCLUSION

Implementation of the laborist model was associated with a significant reduction in labor induction rate and preterm birth without adversely affecting other outcomes.

CKD Progression and Mortality among Hispanics and Non-Hispanics

Although recommended approaches to CKD management are achieved less often in Hispanics than in non-Hispanics, whether long-term outcomes differ between these groups is unclear. In a prospective longitudinal analysis of participants enrolled into the Chronic Renal Insufficiency Cohort (CRIC) and Hispanic-CRIC Studies, we used Cox proportional hazards models to determine the association between race/ethnicity, CKD progression (50% eGFR loss or incident ESRD), incident ESRD, and all-cause mortality, and linear mixed-effects models to assess differences in eGFR slope. Among 3785 participants, 13% were Hispanic, 43% were non-Hispanic white (NHW), and 44% were non-Hispanic black (NHB). Over a median follow-up of 5.1 years for Hispanics and 6.8 years for non-Hispanics, 27.6% of all participants had CKD progression, 21.3% reached incident ESRD, and 18.3% died. Hispanics had significantly higher rates of CKD progression, incident ESRD, and mean annual decline in eGFR than did NHW (P<0.05) but not NHB. Hispanics had a mortality rate similar to that of NHW but lower than that of NHB (P<0.05). In adjusted analyses, the risk of CKD progression did not differ between Hispanics and NHW or NHB. However, among nondiabetic participants, compared with NHB, Hispanics had a lower risk of CKD progression (hazard ratio, 0.61; 95% confidence interval, 0.39 to 0.95) and incident ESRD (hazard ratio, 0.50; 95% confidence interval, 0.30 to 0.84). At higher levels of urine protein, Hispanics had a significantly lower risk of mortality than did non-Hispanics (P<0.05). Thus, important differences in CKD progression and mortality exist between Hispanics and non-Hispanics and may be affected by proteinuria and diabetes.

Abstract OT1-03-06: LORELEI: A phase II randomized, double-blind study of neoadjuvant letrozole plus taselisib (GDC-0032) versus letrozole plus placebo in postmenopausal women with ER-positive/ HER2-negative, early-stage breast cancer

Background: Taselisib is an orally bioavailable, potent, selective inhibitor of Class I PI3-kinase (PI3K) alpha, gamma, and delta isoforms, with 30-fold less inhibition of the PI3K beta isoform relative to the alpha isoform showing enhanced activity against PIK3CA mutant cancer cell lines. Clinical data have demonstrated confirmed partial responses in patients with PIK3CA mutant breast cancer (BC) treated with single-agent taselisib. Enhanced antitumor activity has been noted when taselisib is combined with either letrozole or fulvestrant in preclinical and Phase Ib clinical studies.

Methods: LORELEI is a Phase II, two-arm, randomized, double-blind, multicenter, study of neoadjuvant letrozole and taselisib versus letrozole and placebo in postmenopausal women with newly diagnosed ER+/HER2-, untreated, Stage I-III operable BC. Other eligibility criteria include tumor size  2 cm by magnetic resonance imaging (MRI), ECOG PS 0-1, and evaluable tumor tissue for PIK3CA genotyping. Patients treated with anti-diabetic drugs are not eligible. Patients are randomized (1:1) to receive continuous letrozole (2.5 mg) with either taselisib (4 mg on a 5 days on/ 2 days off schedule) or placebo for 16 weeks, followed by surgery. Stratification is based on tumor size and nodal status. The co-primary endpoints are overall objective response rate (ORR) by centrally assessed breast MRI via modified RECIST criteria and pathologic complete response (pCR) rate in breast and axilla at time of surgery in all randomized patients and PIK3CA mutant patients. Secondary endpoints include ORR by centrally-assessed MRI and pCR rate in PIK3CA wild-type patients. The sample size was calculated to detect an absolute percentage increase of 24% in ORR with 80% power and an absolute percentage increase of 18% in pCR rate. An interim safety analysis will be conducted by an Independent Data Monitoring Committee. As of 1st Jun 2015, 54 of the 330 patients have been enrolled, and global enrollment is ongoing (clinicaltrials.gov NCT02273973).

Contact information:

Reference Study ID Numbers: GO28888/BIG-3-13/SOLTI 1205/ABCSG 38

Phone: 888-662-6728 (US Only)

Email Address: global.rochegenentechtrials@roche.com

Citation Format: Oliveira M, de Azambuja E, Saura C, Dubsky P, Zardavas D, Fesl C, Bardia A, Soberino J, Ciruelos Gil E, Ng V, Fredrickson J, Stout TJ, Singel SM, Hsu JY, Piccart M, Gnant M, Baselga J. LORELEI: A phase II randomized, double-blind study of neoadjuvant letrozole plus taselisib (GDC-0032) versus letrozole plus placebo in postmenopausal women with ER-positive/ HER2-negative, early-stage breast cancer. [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 OT1-03-06.

Surrogate markers for time-varying treatments and outcomes

BACKGROUND

A surrogate marker is a variable commonly used in clinical trials to guide treatment decisions when the outcome of ultimate interest is not available. A good surrogate marker is one where the treatment effect on the surrogate is a strong predictor of the effect of treatment on the outcome. We review the situation when there is one treatment delivered at baseline, one surrogate measured at one later time point, and one ultimate outcome of interest and discuss new issues arising when variables are time-varying.

METHODS

Most of the literature on surrogate markers has only considered simple settings with one treatment, one surrogate, and one outcome of interest at a fixed time point. However, more complicated time-varying settings are common in practice. In this article, we describe the unique challenges in two settings, time-varying treatments and time-varying surrogates, while relating the ideas back to the causal-effects and causal-association paradigms.

CONCLUSION

In addition to discussing and extending popular notions of surrogacy to time-varying settings, we give examples illustrating that one can be misled by not taking into account time-varying information about the surrogate or treatment. We hope this article has provided some motivation for future work on estimation and inference in such settings.

Relation of aortic valve calcium to chronic kidney disease (from the Chronic Renal Insufficiency Cohort Study)

Although subjects with chronic kidney disease (CKD) are at markedly increased risk for cardiovascular mortality, the relation between CKD and aortic valve calcification has not been fully elucidated. Also, few data are available on the relation of aortic valve calcification and earlier stages of CKD. We sought to assess the relation of aortic valve calcium (AVC) with estimated glomerular filtration rate (eGFR), traditional and novel cardiovascular risk factors, and markers of bone metabolism in the Chronic Renal Insufficiency Cohort (CRIC) Study. All patients who underwent aortic valve scanning in the CRIC study were included. The relation between AVC and eGFR, traditional and novel cardiovascular risk factors, and markers of calcium metabolism were analyzed using both unadjusted and adjusted regression models. A total of 1,964 CRIC participants underwent computed tomography for AVC quantification. Decreased renal function was independently associated with increased levels of AVC (eGFR 47.11, 44.17, and 39 ml/min/1.73 m2, respectively, p<0.001). This association persisted after adjusting for traditional, but not novel, AVC risk factors. Adjusted regression models identified several traditional and novel risk factors for AVC in patients with CKD. There was a difference in AVC risk factors between black and nonblack patients. In conclusion, our study shows that eGFR is associated in a dose-dependent manner with AVC in patients with CKD, and this association is independent of traditional cardiovascular risk factors.

Hepatic pathology among patients without known liver disease undergoing bariatric surgery: observations and a perspective from the longitudinal assessment of bariatric surgery (LABS) study

Liver biopsy is not routine during bariatric surgery. Alanine aminotransferase (ALT) is widely used to screen for liver disease. We assessed the relationship between ALT and pathology in biopsies from Longitudinal Assessment of Bariatric Surgery (LABS) patients with normal preoperative ALTs. Biopsies from the LABS-1 and LABS-2 studies were scored using the NASH CRN and Ishak systems. Diagnosis and histology were examined in relation to alanine aminotransferase (ALT) values. Six-hundred ninety-three suitable biopsies were evaluated. Biopsied patients had a median age of 45 years; 78.6% were female and 35.1% diabetic; median body mass index was 46 kg/m(2). Six-hundred thirty-five biopsied patients had preoperative ALTs. Median ALT was 25 IU/L (interquartile range [IQR] 19-36 IU/L); 26.6% had an ALT > 35 IU/L and 29.9% exceeded the more restrictive Prati criteria for normal. Using the Prati criteria, 7.9% of participants with normal ALT had steatohepatitis and 5.3% had ≥ stage 2 fibrosis. Logistic regression models were used to predict the probabilities of having bridging fibrosis/cirrhosis or a diagnosis of borderline/definite steatohepatitis in the unbiopsied LABS-2 sample. The proportion of biopsied participants with these findings was very similar to the modeled results from the unbiopsied cohorts. We estimated that 86.0% of participants with advanced fibrosis and 88.1% of participants with borderline/definite steatohepatitis were not biopsied and went undiagnosed. As ALT did not reliably exclude significant obesity-related liver disease in bariatric surgery patients, consideration should be given to routine liver biopsy during bariatric surgery and medical follow-up of significant hepatic pathology.

Abstract PD1-3: Ph1b study of the PI3K inhibitor GDC-0032 in combination with fulvestrant in patients with hormone receptor-positive advanced breast cancer

Background: GDC-0032 is a next-generation PI3K inhibitor with increased anti-tumor activity against PIK3CA mutant cancers. GDC-0032 is an orally bioavailable, potent, and selective inhibitor of Class I PI3K alpha, delta, and gamma isoforms, with 30-fold less inhibition of the PI3K beta isoform relative to the PI3K alpha isoform. Preclinical data show that GDC-0032 has enhanced activity against PI3K alpha isoform (PIK3CA) mutant breast cancer cell lines. Preclinical data also show enhanced antitumor activity when GDC-0032 is combined with fulvestrant.

Material and Methods: A Phase 1b dose escalation study was conducted with evaluation of GDC-0032 doses ranging from 6-9 mg QD in combination with fulvestrant 500mg q4wk (with loading dose of 500mg at day 1, 14 and 28) in a modified 3+3 design. A dose expansion cohort was conducted at the recommended Phase 2 dose of 6 mg QD. Safety and tolerability of GDC-0032 was assessed, as well as pharmacokinetics (PK), pharmacodynamic (PD) assessment of PI3K pathway inhibition by paired tumor biopsies and by FDG-PET, and anti-tumor activity by RECIST.

Results: As of 1 Mar 2013, 17 patients were enrolled onto this study with the completion of dose escalation. No dose limiting toxicities (DLTs) were observed at either the 6 mg or 9 mg dose levels. Adverse events (AEs) assessed by the investigator as related to GDC-0032 in ≥10% of patients, were diarrhea, hyperglycemia, stomatitis, fatigue, asthenia, decreased appetite, nausea, mucosal inflammation and rash. No observed apparent PK interactions were observed between GDC-0032 and fulvestrant. The median number of prior systemic therapies was 6. Metabolic partial responses via FDG-PET (≥ 20% decrease in mSUVmax) were observed in 8 out of 11 patients assessed (73%). Confirmed partial responses by RECIST have been observed at both the 6mg and 9mg GDC-0032 dose levels. These include patients who have had prior treatment with fulvestrant. As of 29 May 2013, enrollment onto the dose escalation and expansion cohort has been completed (n = 27). Updated data on safety, pharmacodynamics, efficacy, and biomarker correlates will be presented.

Conclusions: The combination of GDC-0032 and fulvestrant is a well-tolerated regimen with promising preliminary efficacy. GDC-0032 is being further investigated in combination with fulvestrant for patients with hormone receptor-positive advanced breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr PD1-3.

Reporting weight change: standardized reporting accounting for baseline weight

BACKGROUND

Although it is recognized that a standardized approach to reporting weight change is essential to meaningful comparisons among cohorts and across studies, consensus is lacking. This study aimed to propose a method of reporting weight change that would allow meaningful comparisons among studies of patients who underwent bariatric surgery and to demonstrate its utility using an example from the Longitudinal Assessment of Bariatric Surgery (LABS).

METHODS

Relationships among several measures of weight change are described. Results from an observational, longitudinal cohort study of adults undergoing bariatric surgery and from simulation studies are used to illustrate the proposed method.

RESULTS

Baseline weight is a critical parameter when assessing weight change. Men undergoing a bariatric procedure other than gastric bypass or adjustable band tended to have greater weight loss 12 months after surgery than men undergoing gastric bypass when not accounting for baseline weight, but the opposite was found when results were adjusted for baseline weight. Simulation results show that with relatively modest sample sizes, the adjusted weight loss was significantly different between the 2 groups of men.

CONCLUSION

A consistent metric for reporting weight loss after bariatric surgery is essential to interpret outcomes across studies and among subgroups. The baseline weight adjusted percent of weight loss (A%WL) uses a standard population (e.g., the LABS cohort) to account for differences between cohorts with respect to baseline weight, and its use can change the interpretation of results compared with an unadjusted measure.

Pre- to postoperative changes in physical activity: report from the longitudinal assessment of bariatric surgery-2 (LABS-2)

BACKGROUND

Numerous studies have reported that bariatric surgery patients report more physical activity (PA) after surgery than before; however, the quality of the PA assessment has been questionable.

METHODS

The longitudinal assessment of bariatric surgery-2 is a 10-center longitudinal study of adults undergoing bariatric surgery. Of 2458 participants, 455 were given an activity monitor, which records the steps per minute, and an exercise diary before and 1 year after surgery. The mean number of steps/d, active min/d, and high-cadence min/wk were calculated for 310 participants who wore the monitor ≥10 hr/d for ≥3 days at both evaluations. Pre- and postoperative PA were compared for differences using the Wilcoxon signed-rank test. Generalized estimating equations were used to identify independent preoperative predictors of postoperative PA.

RESULTS

PA increased significantly (P < .0001) from before to after surgery for all PA measures. The median values before and after surgery were 7563 and 8788 steps/d, 309 and 340 active min/d, and 72 and 112 high-cadence min/wk, respectively. However, depending on the PA measure, 24-29% of participants were ≥5% less active postoperatively than preoperatively. Controlling for surgical procedure, gender, age, and body mass index, more PA preoperatively independently predicted for more PA postoperatively (P < .0001, for all PA measures). Less pain, not having asthma, and the self-report of increasing PA as a weight loss strategy preoperatively also independently predicted for more high-cadence min/wk postoperatively (P < .05).

CONCLUSIONS

The majority of adults increase their PA level after bariatric surgery. However, most remain insufficiently active, and some become less active. Increasing PA, addressing pain, and treating asthma before surgery might have a positive effect on postoperative PA.

Classical reflux symptoms, hiatus hernia and overweight independently predict pharyngeal acid exposure in patients with suspected reflux laryngitis

BACKGROUND

Gastro-oesophageal reflux disease (GERD) has been associated with reflux laryngitis.

AIMS

To investigate the risk factors and the predictors of pharyngeal acid reflux (PAR) in Taiwanese patients with suspected reflux laryngitis.

METHODS

With referral from ENT physicians, 104 patients with symptoms and signs suggestive of reflux laryngitis completed a validated symptom questionnaire, an upper endoscopy exam and ambulatory 24-h pH tests with three sensors located at the hypopharynx, proximal and distal oesophagus. Patients with one or more episodes of PAR were considered abnormal.

RESULTS

Pharyngeal acid reflux was identified in 17% (18/104) of patients. In multivariate logistic regression analysis, PAR was independently associated with classical reflux symptoms [adjusted odds ratio (aOR) = 3.5, 95% confidence interval (CI): 1.0-12.8], hiatus hernia (aOR = 6.7, 95% CI: 1.5-30.2) and overweight (aOR = 3.4, 95% CI: 1.0-11.0). In predicting PAR, classical reflux symptoms had a sensitivity of 78% and hiatus hernia had a specificity of 95%. With all three factors, the positive predictive value for PAR was 80%. Classical reflux symptoms included heartburn, chest pain, dyspepsia and acid regurgitation.

CONCLUSIONS

Classical reflux symptoms, hiatus hernia and overweight are independent risk factors that may predict pharyngeal acid reflux in patients with suspected reflux laryngitis.

Nanolayer parametric instability in near-field optics

Parametric decay of electromagnetic waves into two Langmuir oscillations near the quarter critical density is suggested as being attributable to an enhanced electric field and to surface-enhanced Raman scattering in near-field optics. A nanolayer of silver aggregates localizes the wave in the evanescent region to a one-wavelength span and results in a wave-number mismatch as well as in a reduced growth rate. The fastest-growing mode has a growth rate that scales with the square root of the nanolayer's thickness.

Derivation of the density functional theory from the cluster expansion

The density functional theory is derived from a cluster expansion by truncating the higher-order correlations in one and only one term in the kinetic energy. The formulation allows self-consistent calculation of the exchange correlation effect without imposing additional assumptions to generalize the local density approximation. The pair correlation is described as a two-body collision of bound-state electrons, and modifies the electron- electron interaction energy as well as the kinetic energy. The theory admits excited states, and has no self-interaction energy.

Emi1 is a mitotic regulator that interacts with Cdc20 and inhibits the anaphase promoting complex

We have discovered an early mitotic inhibitor, Emi1, which regulates mitosis by inhibiting the anaphase promoting complex/cyclosome (APC). Emi1 is a conserved F box protein containing a zinc binding region essential for APC inhibition. Emi1 accumulates before mitosis and is ubiquitylated and destroyed in mitosis, independent of the APC. Emi1 immunodepletion from cycling Xenopus extracts strongly delays cyclin B accumulation and mitotic entry, whereas nondestructible Emi1 stabilizes APC substrates and causes a mitotic block. Emi1 binds the APC activator Cdc20, and Cdc20 can rescue an Emi1-induced block to cyclin B destruction. Our results suggest that Emi1 regulates progression through early mitosis by preventing premature APC activation, and may help explain the well-known delay between cyclin B/Cdc2 activation and cyclin B destruction.

Reduced 1alpha-hydroxylase activity in human prostate cancer cells correlates with decreased susceptibility to 25-hydroxyvitamin D3-induced growth inhibition

Evidence from epidemiological, molecular, and genetic studies suggests a role for vitamin D in the development and/or progression of prostate cancer. In experimental models and clinical trials, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] was shown to exert antiproliferative, prodifferentiating, and antimetastatic/invasive effects on prostatic epithelial cells. Because the direct clinical application of 1,25(OH)2D3 is limited by the major side effect of hypercalcemia, we investigated the potential therapeutic utility of its less calcemic precursor, 25-hydroxyvitamin D3 [25(OH)D3], which is converted locally within the prostate to 1,25(OH)2D3 by 1alpha-hydroxylase. Quantification of 1alpha-hydroxylase activity in human prostatic epithelial cells by enzyme-substrate reaction analyses revealed a significantly decreased activity in cells derived from adenocarcinomas compared with cells derived from normal tissues or benign prostatic hyperplasia (BPH). In growth assays, we found that 25(OH)D3 inhibited growth of normal or BPH cells similarly to 1,25(OH)2D3. In contrast, in primary cultures of cancer cells and established cell lines, the antiproliferative action of 25(OH)D3 was significantly less pronounced than that of 1,25(OH)2D3. Our results indicate that growth inhibition by 25(OH)D3 depends on endogenous 1alpha-hydroxylase activity, and that this activity is deficient in prostate cancer cells. This finding has ramifications for both the prevention and therapy of prostate cancer with vitamin D compounds.

Diffuse leiomyomatosis of the esophagus

BACKGROUND

Leiomyomas are rare esophagus neoplasms. They are usually solitary, and the diffuse lesion is extremely rare.

CASE REPORT

A 19-year-old male presented with a 3-year history of occasional dysphagia and postprandial regurgitation. The chest radiographs showed a huge mass in the posterior mediastinum. Barium esophagograms showed narrowing of the middle third esophagus with proximal dilatation. The fibroesophagoscopy demonstrated multiple submucosal nodules below a level 22 cm from the incisor and covered with intact mucosa. CT scans of the chest showed a long segment of circumferential soft tissue in the posterior mediastinum which encircled and involved the upper two thirds of the esophagus. An intrathoracic esophagectomy with cervical esophagogastrostomy via the substernal route was performed. Grossly, multiple confluent myomatous nodules circumferentially involved the upper and middle third of the esophagus. Histologic findings showed diffuse leiomyomatosis of the esophagus.

CONCLUSION

Esophageal leiomyomatosis should be considered in a young patient with long-standing dysphagia in whom smooth, tapered esophageal narrowing on barium study and circumferential esophageal wall thickening on CT scan are seen. An esophagectomy combined with a reconstruction procedure is indicated.

The lore of the RINGs: substrate recognition and catalysis by ubiquitin ligases

Recently, many new examples of E3 ubiquitin ligases or E3 enzymes have been found to regulate a host of cellular processes. These E3 enzymes direct the formation of multiubiquitin chains on specific protein substrates, and - typically - the subsequent destruction of those proteins. We discuss how the modular architecture of E3 enzymes connects one of two distinct classes of catalytic domains to a wide range of substrate-binding domains. In one catalytic class, a HECT domain transfers ubiquitin directly to substrate bound to a non-catalytic domain. Members of the other catalytic class, found in the SCF, VBC and APC complexes, use a RING finger domain to facilitate ubiquitylation. The separable substrate-recognition domains of E3 enzymes provides a flexible means of linking a conserved ubiquitylation function to potentially thousands of ubiquitylated substrates in eukaryotic cells.

Mitotic phosphorylation of histone H3 is governed by Ipl1/aurora kinase and Glc7/PP1 phosphatase in budding yeast and nematodes

Phosphorylation of histone H3 at serine 10 occurs during mitosis and meiosis in a wide range of eukaryotes and has been shown to be required for proper chromosome transmission in Tetrahymena. Here we report that Ipl1/aurora kinase and its genetically interacting phosphatase, Glc7/PP1, are responsible for the balance of H3 phosphorylation during mitosis in Saccharomyces cerevisiae and Caenorhabditis elegans. In these models, both enzymes are required for H3 phosphorylation and chromosome segregation, although a causal link between the two processes has not been demonstrated. Deregulation of human aurora kinases has been implicated in oncogenesis as a consequence of chromosome missegregation. Our findings reveal an enzyme system that regulates chromosome dynamics and controls histone phosphorylation that is conserved among diverse eukaryotes.

Phosphorylation of serine 10 in histone H3 is functionally linked in vitro and in vivo to Gcn5-mediated acetylation at lysine 14

Multiple covalent modifications exist in the amino-terminal tails of core histones, but whether a relationship exists between them is unknown. We examined the relationship between serine 10 phosphorylation and lysine 14 acetylation in histone H3 and have found that, in vitro, several HAT enzymes displayed increased activity on H3 peptides bearing phospho-Ser-10. This augmenting effect of Ser-10 phosphorylation on acetylation by yGcn5 was lost by substitution of alanine for arginine 164 [Gcn5(R164A)], a residue close to Ser-10 in the structure of the ternary tGcn5/CoA/histone H3 complex. Gcn5(R164A) had reduced activity in vivo at a subset of Gcn5-dependent promoters, and, strikingly, transcription of this same subset of genes was also impaired by substitution of serine 10 to alanine in the histone H3 tail. These observations suggest that transcriptional regulation occurs by multiple mechanistically linked covalent modifications of histones.

E-cadherin expression in melanoma cells restores keratinocyte-mediated growth control and down-regulates expression of invasion-related adhesion receptors

In human epidermis, functional symbiosis requires homeostatic balance between keratinocytes and melanocytes. Compelling evidence from co-culture studies demonstrated a sophisticated, multileveled regulation of normal melanocytic phenotype orchestrated by undifferentiated, basal-type keratinocytes. Keratinocytes control cell growth and dendricity, as well as expression of melanoma-associated cell surface molecules of normal melanocytes. In contrast, melanoma cells are refractory to the keratinocyte-mediated regulation. The loss of regulatory dominance by keratinocytes occurs in concert with down-regulation of E-cadherin expression in melanoma cells. To investigate the potential role of E-cadherin in melanoma-keratinocyte interaction, we transduced E-cadherin-negative melanoma cells with full-length E-cadherin cDNA using an adenoviral vector. Our results show that functional E-cadherin expression in melanoma cells leads to cell adhesion to keratinocytes rendering them susceptible for keratinocyte-mediated control. In a skin reconstruction model, ectopic E-cadherin expression inhibits invasion of melanoma cells into dermis by down-regulating invasion-related adhesion receptors, MelCAM/MUC18 and beta3 integrin subunit, and by induction of apoptosis. Thus, disruption of the E-cadherin-mediated, normal regulatory control from keratinocytes may represent one of the mechanisms accounting for melanocyte transformation.

Heparin/endothelial cell growth supplement regulates matrix gene expression and prolongs life span of vascular smooth muscle cells through modulation of interleukin-1

Vascular smooth muscle cells produce and respond to interleukin-1, a cytokine which modifies inflammation-associated vascular activities including the synthesis of extracellular matrix proteins. We have established vascular smooth muscle cells culture conditions in which heparin, in the presence of endothelial cell growth supplement, promotes cell proliferation and inhibits interleukin-1 and matrix protein expression. To test whether interleukin-1 mediates growth and matrix modulation by heparin/endothelial cell growth supplement, vascular smooth muscle cells were transfected with an Epstein-Barr virus-derived expression vector designed to express interleukin-1 antisense transcripts. RNase protection and ELISA assays demonstrated a complete block of interleukin-1 transcription and protein synthesis. Northern blot analysis also showed that interleukin-1 antisense decreased the expression of matrix genes such as type I collagen, fibronectin, and decorin similar to downregulation after heparin/endothelial cell growth supplement treatment. In contrast, the expression of versican was not affected, indicating a selective suppression of matrix proteins. In addition, interleukin-1 antisense significantly prolonged the life span of vascular smooth muscle cells in culture. Our data suggest that heparin/endothelial cell growth supplement induces matrix remodeling and controls growth and senescence of vascular smooth muscle cells through down-regulation of interleukin-1.

Expression and cellular localization of ribonucleotide reductase small subunit M2 protein in hydroxyurea-resistant Leishmania mexicana amazonensis

We raised a specific antiserum against the recombinant M2 subunit protein of ribonucleotide reductase of Leishmania mexicana amazonensis in rabbit. This antiserum was used to study the expression and cellular location of the M2 protein in wildtype as well as hydroxyurea-resistant variants (HuR) of the parasite. The protein increased with increasing dose of the drug used for selection of resistance. The increase in protein level was accompanied by an increase in the copy numbers of mRNA of the M2 gene in the variants. In contrast to mammalian cells, the M2 protein of Leishmania is located in the nucleus rather than in the cytoplasm. The number of cells expressing M2 protein is also different in mammalian cells versus Leishmania. In mammalian cells, expression of M2 protein is a strictly S-phase-correlated event and in exponentially growing cells only approximately 50% of the cells are in S-phase and only these cells synthesize M2 protein. In L. m. amazonensis, however, almost all exponentially growing cells are positive for M2 protein. This makes it unlikely that M2 protein expression in Leishmania is S-phase dependent. In view of these findings, a fresh look in the future into the regulatory mechanisms of synthesis and the site of action of RNR in L. m. amazonensis is warranted.

Characterization by pulse-field electrophoresis of a new region of DNA amplification containing the M2 subunit of ribonucleotide reductase in hydroxyurea-resistant Leishmania

An extrachromosomal circular DNA of of approximately 50-kb size was amplified in the hydroxyurea-resistant variant of Leishmania mexicana amazonensis. The amplicon carried the M2 gene of ribonuleotide reductase as part of the gene encoding resistance to hydroxyurea. The amplicon was unstable. It disappeared rapidly as shown in pulse-field gradient electrophoresis gels after reversion of the cells for 20-80 days. This loss of amplified DNA was accompanied by a rapid loss of resistance to hydroxyurea during the same period. The amplicon was not hybridized to specific probes from any of the four regions of DNA amplification previously reported for Leishmania. This region of amplification thus appears to be a new region of DNA amplification in Leishmania.

ET-1 expression and growth inhibition of prostate cancer cells: a retinoid target with novel specificity

Endothelin-1 (ET-1) is not only a potent vasoconstrictor but also serves as an important growth stimulator in various cancers, including breast, cervical, pancreatic, and prostate cancer. This suggests that blockage of ET-1 production may suppress tumor growth and possibly metastasis. We observed that certain synthetic retinoids, and all-trans-retinoic acid can repress LNCaP prostate cancer cell growth in vitro. In addition, these retinoid compounds counteracted exogenous ET-1-induced growth stimulation. Retinoid-dependent growth retardation of LNCaP cells coincided with suppression of ET-1 gene expression to a level undetectable by reverse transcription-PCR. Contrarily, the androgen-insensitive DU145 cells were refractory to retinoid treatment. To investigate the underlying mechanisms of the cell-specific response to retinoids, we transfected ET-1 promoter constructs containing wild-type or mutated AP-1 or GATA-2 site into prostate cancer cells. Distinct regulations of ET-1 promoter activity were found; in LNCaP cells, both binding sites are essential for optimal promoter activation, whereas in DU145 cells, additional promoter sequences and/or transcriptional factors seem to be involved. Furthermore, several anti-AP-1 selective retinoids failed to repress ET-1 promoter activity and to exhibit a cell growth-inhibitory effect on LNCaP cells, suggesting that different retinoid structural configurations are required for the inhibition of an AP-1 complex versus an AP-1/GATA-2 complex.

Adenoviral gene transfer of beta3 integrin subunit induces conversion from radial to vertical growth phase in primary human melanoma

Expression of the beta3 subunit of the alphavbeta3 vitronectin receptor on melanoma cells is associated with tumor thickness and the ability to invade and metastasize. To address the role of alphavbeta3 in the complex process of progression from the nontumorigenic radial to the tumorigenic vertical growth phase of primary melanoma, we examined the biological consequences of overexpressing alphavbeta3 in early-stage melanoma cells using an adenoviral vector for gene transfer. Overexpression of functional alphavbeta3 in radial growth phase primary melanoma cells 1) promotes both anchorage-dependent and -independent growth, 2) initiates invasive growth from the epidermis into the dermis in three-dimensional skin reconstructs, 3) prevents apoptosis of invading cells, and 4) increases tumor growth in vivo. Thus, alphavbeta3 serves diverse biological functions during the progression from the nontumorigenic radial growth phase to the tumorigenic and-invasive vertical growth phase primary melanoma.

Preliminary result of phase II study of paclitaxel and cisplatin chemotherapy for advanced non-small-cell lung cancer in Chinese patients

This phase II study was designed to assess the response rate and toxicity of paclitaxel and cisplatin chemotherapy in Chinese patients with untreated advanced non-small-cell lung cancer (NSCLC). Eligibility requirements included histologically confirmed stage IIIb-IV NSCLC, Eastern Cooperative Oncology Group performance status less than 2, no previous chemotherapy, and adequate bone marrow, renal, and hepatic function. From April 1996 through March 1997, 32 patients were treated. The dose of paclitaxel was 135 mg/m2 as a 3-hour infusion on day 1 and cisplatin 75 mg/m2 on day 2. The regimen was repeated every 3 to 4 weeks for up to 6 to 8 cycles unless there was evidence of tumor progression. The median age was 57 years (range, 31-77 years). Sixty-five percent were men. Sixty-nine percent had adenocarcinoma, and 75% had stage IV disease. One hundred seventy-two cycles were administrated; 18 patients (56%) completed all six cycles. Peripheral neuropathy and myelosuppression were the principle toxicities. Neurotoxicity appeared to be dose limiting and manifested primarily as paresthesia. Grade 2 neurotoxicity was observed in 5% of courses, which was slowly reversible. However, the severity of myelosuppression was generally mild to moderate. No episode of neutropenic fever was noted. Thrombocytopenia remained infrequent throughout the study. Other nonhematologic toxicities were also generally mild. The objective response rate was 50%. In conclusion, this combination of paclitaxel and cisplatin is active in Chinese patients with advanced NSCLC. It merits further investigation in phase III trials.

Color Doppler ultrasound pulsatile flow signals of thoracic lesions: comparison of lung cancers and benign lesions

Color Doppler ultrasound (US) was performed in 153 patients (including 102 with lung cancer and 51 with benign lesions) to assess pulsatile flow signals in thoracic lesions. The values of resistive index (RI) and pulsatility index (PI) of color Doppler US pulsatile flow signals in lung cancers and benign lesions were measured, analyzed, and compared. In the enrolled 153 patients with thoracic lesions, 61 lung cancers and 34 benign lesions had detectable color Doppler US pulsatile flow signals, and lung cancers had lower RI and PI values than benign lesions (RI: 0.70+/-0.03 vs. 0.79+/-0.04, p < 0.05; PI: 1.61+/-0.15 vs. 2.44+/-0.25, p < 0.005). However, overlapping RI and PI values in lung cancers and benign lesions somewhat limited color Doppler US pulsatile flow signals to differentiate lung cancers from benign lesions. Further analysis of RI and PI values in subgroups of lung cancers [squamous cell carcinoma (SCC, n = 34), adenocarcinoma (AC, n = 18), and small-cell lung cancer (SCLC, n = 6)] and benign lesions [cavitary benign lesions (CBL, n = 8), and noncavitary benign lesions (NCBL, n = 26)] revealed that all different cell types of lung cancers (SCC, AC, and SCLC), indeed, had lower RI and PI values than NCBL (for RI, all p < 0.01; for PI, all p< or =0.001). Moreover, the mean RI and PI values showed a significant incremental decrease from NCBL (mean RI, PI = 0.88, 2.94) toward SCC and AC (for SCC, mean RI, PI = 0.71, 1.68; for AC, mean RI, PI = 0.68, 1.67) and, finally, to SCLC (mean RI, PI = 0.62, 1.05). In contrast, CBL had relatively lower RI and PI values than AC and SCLC (for CBL, mean RI, PI = 0.53, 0.80; both p > 0.05 for RI and PI), and even a significant difference from SCC (p < 0.05 for RI and PI). We conclude that color Doppler US pulsatile flow signal is somewhat limited to differentiate lung cancers from benign lesions, but provides a noninvasive in vivo model to assess the neovascularity intensity of lung cancers.

Ultrasound-guided small-bore Elecath tube insertion for the rapid sclerotherapy of malignant pleural effusion

BACKGROUND

Traditional pleurodesis for malignant pleural effusion is performed by large-bore chest tube insertion with the instillation of sclerosing agents after the compressed lung re-expansion and pleural fluid drainage of 100-150 ml/day. This study was carried out to evaluate the possibility of rapid sclerotherapy for malignant pleural effusions by insertion of a small-bore Elecath tube (12-French) under ultrasound guidance and intrapleural injection of bleomycin 60 IU.

METHODS

Twenty-six patients, with 28 cytopathologically proven malignant pleural effusions (two patients had bilateral pleural effusions) and receiving the insertion of the Elecath tube for drainage, were included in our series. This rapid and short-term sclerosing method was performed and completed by intrapleural injection of bleomycin when the pleural effusion had been clearly drained by the small-bore Elecath tube and the compressed lung had fully re-expanded on follow-up chest radiographs.

RESULTS

Twenty patients with 22 pleural effusions underwent the intrapleural injection of bleomycin, with the results of pleurodesis being complete response 41% (9/22), partial response 36% (8/22) and failure 23% (5/22). Interestingly, among the 17 successful procedures of pleurodesis (complete response and partial response), 71% (12) procedures could be completed within 2 days (seven within one day and five within 2 days). The remaining unsuccessful procedures carried out on six patients without the injection of bleomycin were due to a non-re-expanded lung (n = 3) and inadequate drainage (n = 3); of these, four patients also received the large-bore chest tube insertion after the removal of the Elecath tube, but the compressed lung still could not re-expand. The complications of the bleomycin injection were fever [77% (17/22)], vomiting [14% (3/22)] and hiccup [5% (1/22)].

CONCLUSION

The method of rapid sclerotherapy for malignant pleural effusions by small-bore Elecath tube is promising, with a success rate achieving 77%, usually within 2 days.

Ultrasound-guided fine needle aspiration biopsy in the diagnosis of chronic pulmonary infection

Fourteen patients, with abnormalities on their chest radiographs found over a period of > or = 4 weeks and diagnosed as chronic pulmonary infections in the follow-up, underwent ultrasound-guided fine-needle aspiration biopsy (US-guided FNAB). Six patients also underwent color Doppler ultrasound examination before needle aspiration biopsy. Nine patients had a confirmed diagnosis [tuberculosis (n = 1), cryptococcosis (n = 3), actinomycosis (n = 2), and aspergillosis (n = 1)] or a suggestive diagnosis [caseating granulomatous inflammation (n = 1) and caseous necrosis (n = 1)] made after US-guided FNAB. The remaining 5 patients were finally diagnosed by US-guided large-bore cutting biopsy (n = 1, tuberculosis) and surgical resection [aspergillosis and organized pneumonia (n = 1), mucormycosis and organized pneumonia (n = 1), penicillium infection and organized pneumonia (n = 1), and cryptococcosis (n = 1)]. In 8 patients receiving gray scale US examination only, complications developed in 2 patients after US-guided FNAB [minimal pneumothorax (n = 1) and hemoptysis (n = 1)]. Of the 6 patients who also underwent color Doppler US examination, 4 had detectable blood vessels within the lesion. Thus, the site for US-guided FNAB was changed in 2 patients to prevent injury to prominent blood vessels. There were no complications observed following color Doppler US examination. We conclude that US-guided FNAB is useful for diagnosing chronic pulmonary infections, and color Doppler US is valuable for preventing injury to blood vessels.

Importance of sputum differential cell counting in the diagnosis of airway diseases

We examined the sputum of 114 subjects by noninvasive methods (voluntary coughing or induced cough with hypertonic saline) to determine whether sputum examination could be used to separate patients with episodic wheezing, dyspnea or cough of unknown origin into different diagnostic categories. An increased percentage of sputum eosinophils was seen in 92% (48/52) of asthmatics, 36% (9/25) of patients with chronic obstructive pulmonary disease (COPD) and 28% (7/25) of chronic coughers, but not in any of the 12 patients with congestive heart failure (CHF). Eight patients with combined symptoms of COPD and asthma (mixed COPD subgroup) showed above average diurnal peak expiratory flow variation (10.3 +/- 2.1% vs 2.5 +/- 1.4%, p < 0.05) and an above average percentage of sputum eosinophils (19.8 +/- 9.1 vs 2.1 +/- 3.2, p < 0.01) than those in the pure COPD group. After therapeutic corticosteroid trial, all of the mixed COPD patients and six of the 17 pure COPD patients were steroid responders. Seven of the 25 chronic coughers had sputum eosinophilia, but no asthmatic symptoms. The cough symptoms subsided in five of these seven patients after steroid treatment but not in the other 18 chronic coughers. Further study is indicated to determine if simple eosinophilic bronchitis is an early stage of asthma. In conclusion, sputum differential cell counting is a useful noninvasive diagnostic tool in differentiating diseases with episodic wheezing or chronic cough.