External Validation of Equations that Use Demographic and Anthropometric Measurements to Predict Percent Body Fat.

OBJECTIVE: Numerous equation to predict percent body fat using demographics and anthropometrics have been published but external validation of these equations is limited. The objective of this study was to validate published equations that use anthropometrics for prediction of percent body fat using external data. METHODS: Data were from the Visceral Fat, Metabolic Rate, and Coronary Heart Disease Risk I (VIM I) Study and the Fels Longitudinal Study (Fels). VIM I was conducted in a subset of subjects from the CARDIA study and included black and white adults 28-40 years (n = 392). Fels consisted of white participants 8-88 years (n = 1,044). Percent body fat assessed by dual X-ray absorptiometry (DXA) in these two studies was compared to results calculated using 13 equations from Stevens et al. and nine other published equations. RESULTS: In general, the Stevens equations performed better than equations from other studies. For example, equation "I" in women in VIM I, Fels adults, and Fels youth, R2 estimates were 0.765, 0.757 and 0.789, respectively. In men the estimates were 0.702 in VIM I, 0.822 in Fels adults and 0.905 in Fels youth. None of the results from the nine published equations showed R2 this high in corresponding groups. CONCLUSIONS: Our results indicate that several of the Stevens equations have external validity superior to that of nine other published equations among varying age groups, genders and races.

Incidence of components of metabolic syndrome in the metabolically healthy obese over 9 years follow-up: the Atherosclerosis Risk In Communities study.

BACKGROUND: Some obese adults are not afflicted by the metabolic abnormalities often associated with obesity (the 'metabolically healthy obese' (MHO)); however, they may be at increased risk of developing cardiometabolic abnormalities in the future. Little is known about the relative incidence of individual components of metabolic syndrome (MetSyn). METHODS: We used data from a multicenter, community-based cohort aged 45-64 years at recruitment (the Atherosclerosis Risk In Communities study) to examine the first appearance of any MetSyn component, excluding waist circumference. Body mass index (BMI, kg m-2) and cardiometabolic data were collected at four triennial visits. Our analysis included 3969 adults who were not underweight and free of the components of MetSyn at the initial visit. Participants were classified as metabolically healthy normal weight (MHNW), overweight (MHOW) and MHO at each visit. Adjusted hazard ratios (HR) and 95% confidence intervals were estimated with proportional hazards regression models. RESULTS: The relative rate of developing each risk factor was higher among MHO than MHNW, with the strongest association noted for elevated fasting glucose (MHO vs MHNW, HR: 2.33 (1.77, 3.06)). MHO was also positively associated with elevated triglycerides (HR: 1.63 (1.27, 2.09)), low high-density lipoprotein-cholesterol (HR: 1.68 (1.32, 2.13)) and elevated blood pressure (HR: 1.54 (1.26, 1.88)). A similar, but less pronounced pattern was noted among the MHOW vs MHNW. CONCLUSIONS: We conclude that even among apparently healthy individuals, obesity and overweight are related to more rapid development of at least one cardiometabolic risk factor, and that elevations in blood glucose develop most rapidly.

Nationally representative equations that include resistance and reactance for the prediction of percent body fat in Americans.

BACKGROUND/OBJECTIVES: Resistance and reactance collected by bioelectrical impedance (BIA) can be used in equations to estimate percent body fat at relatively low cost and subject burden. To our knowledge, no such equations have been developed in a nationally representative sample. SUBJECTS/METHODS: Dual-energy X-ray absorptiometry assessed percent body fat from the 1999 to 2004 National Health and Nutrition Survey was the criterion method for development of sex-specific percent body fat equations using up to 6467 males or 4888 females 8-49 years of age. Candidate variables were studied in multiple mathematical forms and interactions using the Least Absolute Shrinkage and Selection Operator. Models were fit in 2/3's of the data and validated in 1/3 of the data selected at random. Final coefficients, R2 values and root mean square error (RMSE) were estimated in the full data set. RESULTS: Models that included age, ethnicity, height, weight, BMI and BIA assessments (resistance, reactance and height2/resistance) had R2 values of 0.831 in men and 0.864 in women in the full data set. RMSE measurements were between 2 and 3 body fat percentage points, and all equations showed low bias across groups formed by age, race/ethnicity or body mass index category. The addition of triceps skinfold and waist circumference increased the R2 to 0.905 in males and 0.883 in females. Adding other anthropometrics (plus menses in females) had little impact on performance. Reactance and resistance alone (in multiple mathematical forms) performed poorly with R2~0.2. CONCLUSIONS: Equations that included BIA assessments along with demographic and anthropometric variables provided percent body fat assessments that had high generalizability, strong predictive ability and low bias.

Age-related mutations and chronic myelomonocytic leukemia.

Chronic myelomonocytic leukemia (CMML) is a hematologic malignancy nearly confined to the elderly. Previous studies to determine incidence and prognostic significance of somatic mutations in CMML have relied on candidate gene sequencing, although an unbiased mutational search has not been conducted. As many of the genes commonly mutated in CMML were recently associated with age-related clonal hematopoiesis (ARCH) and aged hematopoiesis is characterized by a myelomonocytic differentiation bias, we hypothesized that CMML and aged hematopoiesis may be closely related. We initially established the somatic mutation landscape of CMML by whole exome sequencing followed by gene-targeted validation. Genes mutated in ⩾10% of patients were SRSF2, TET2, ASXL1, RUNX1, SETBP1, KRAS, EZH2, CBL and NRAS, as well as the novel CMML genes FAT4, ARIH1, DNAH2 and CSMD1. Most CMML patients (71%) had mutations in ⩾2 ARCH genes and 52% had ⩾7 mutations overall. Higher mutation burden was associated with shorter survival. Age-adjusted population incidence and reported ARCH mutation rates are consistent with a model in which clinical CMML ensues when a sufficient number of stochastically acquired age-related mutations has accumulated, suggesting that CMML represents the leukemic conversion of the myelomonocytic-lineage-biased aged hematopoietic system.

ß-Catenin is required for intrinsic but not extrinsic BCR-ABL1 kinase-independent resistance to tyrosine kinase inhibitors in chronic myeloid leukemia.

Activation of nuclear ß-catenin and expression of its transcriptional targets promotes chronic myeloid leukemia (CML) progression, tyrosine kinase inhibitor (TKI) resistance, and leukemic stem cell self-renewal. We report that nuclear ß-catenin has a role in leukemia cell-intrinsic but not -extrinsic BCR-ABL1 kinase-independent TKI resistance. Upon imatinib inhibition of BCR-ABL1 kinase activity, ß-catenin expression was maintained in intrinsically resistant cells grown in suspension culture and sensitive cells cultured in direct contact (DC) with bone marrow (BM) stromal cells. Thus, TKI resistance uncouples ß-catenin expression from BCR-ABL1 kinase activity. In ß-catenin reporter assays, intrinsically resistant cells showed increased transcriptional activity versus parental TKI-sensitive controls, and this was associated with restored expression of ß-catenin target genes. In contrast, DC with BM stromal cells promoted TKI resistance, but had little effects on Lef/Tcf reporter activity and no consistent effects on cytoplasmic ß-catenin levels, arguing against a role for ß-catenin in extrinsic TKI resistance. N-cadherin or H-cadherin blocking antibodies abrogated DC-based resistance despite increasing Lef/Tcf reporter activity, suggesting that factors other than ß-catenin contribute to extrinsic, BM-derived TKI resistance. Our data indicate that, while nuclear ß-catenin enhances survival of intrinsically TKI-resistant CML progenitors, it is not required for extrinsic resistance mediated by the BM microenvironment.

A coiled-coil mimetic intercepts BCR-ABL1 dimerization in native and kinase-mutant chronic myeloid leukemia.

Targeted therapy of chronic myeloid leukemia (CML) is currently based on small-molecule inhibitors that directly bind the tyrosine kinase domain of BCR-ABL1. This strategy has generally been successful, but is subject to drug resistance because of point mutations in the kinase domain. Kinase activity requires transactivation of BCR-ABL1 following an oligomerization event, which is mediated by the coiled-coil (CC) domain at the N terminus of the protein. Here, we describe a rationally engineered mutant version of the CC domain, called CC(mut3), which interferes with BCR-ABL1 oligomerization and promotes apoptosis in BCR-ABL1-expressing cells, regardless of kinase domain mutation status. CC(mut3) exhibits strong proapoptotic and antiproliferative activity in cell lines expressing native BCR-ABL1, single kinase domain mutant BCR-ABL1 (E255V and T315I) or compound-mutant BCR-ABL1 (E255V/T315I). Moreover, CC(mut3) inhibits colony formation by primary CML CD34(+) cells ex vivo, including a sample expressing the T315I mutant. These data suggest that targeting BCR-ABL1 with CC mutants may provide a novel alternative strategy for treating patients with resistance to current targeted therapies.

Bromodeoxyuridine alternating with radiation for advanced uterine cervix cancer: a phase I and drug incorporation study.

PURPOSE: Preclinical studies show a significant increase in the ratio of the radiosensitizer bromodeoxyuridine (BUdR) in tumors versus the intestinal mucosa during the drug elimination period, compared with the ratio during drug infusion. We constructed a phase I study in patients with locally advanced cervix cancer, using alternating cycles of BUdR and radiation therapy (RT). PATIENTS AND METHODS: Eighteen patients with stage IIB to IVA cervix cancer participated. A treatment cycle consisted of a 4-day BUdR infusion followed by a week of pelvic RT, 15 Gy twice daily in 1.5-Gy fractions. After three cycles, additional BUdR was infused, followed by brachytherapy. The fraction of thymidine replaced by BUdR and the fraction of cells incorporating BUdR were determined in rectal mucosa and tumor biopsies at the end of the first BUdR infusion (day 5), at the middle of the first RT week (day 10), and at the time of brachytherapy. RESULTS: Dose-limiting toxicity was observed in one of 16 patients receiving 1,000 mg/m2/d x 4 days and in both patients receiving 1,333 mg/m2/d x 4 days each cycle. After a median follow-up of 39 months, 12 patients (66%) were free of pelvic disease and nine (50%) were alive and disease free. The ratio of tumor to rectum BUdR incorporation averaged 1.5 to 1.8 and did not differ significantly between day 5 and day 10. A trend toward reduced ratio was observed at brachytherapy. Drug-containing cells in rectal biopsies migrated from the crypts to the mucosal surface. CONCLUSION: In this schedule, 1,000 mg/m2/d is the maximum-tolerated dose of BUdR. BUdR incorporation levels in tumors were consistent with clinically significant radiosensitization. The migration of BUdR-containing rectal mucosa cells from the crypts to the surface at the time of RT suggests that this regimen may offer a relative sparing of the mucosa from radiosensitization.

Customized gynecologic interstitial implants: CT-based planning, dose evaluation, and optimization aided by laparotomy.

PURPOSE: Interstitial perineal implants may be utilized to deliver a high local radiation dose in the treatment of advanced gynecologic malignancies. Lack of knowledge of the precise anatomic relationships between the implant and the target and critical organs may limit efficacy and increase complication risks. Computed tomography (CT)-based planning, dose evaluation, and optimization of customized interstitial implants, aided by laparotomy, have been developed to overcome these limitations. METHODS AND MATERIALS: Twenty patients with locally advanced gynecologic malignancies treated between May 1990 to October 1996 with external irradiation and one or two implants. Interstitial implants were performed when intracavitary brachytherapy was judged to be inadequate or when the response to external radiation and an intracavitary implant was not satisfactory. Customized interstitial implants were planned using preimplantation CT to determine catheter angles and paths that best implanted the target while avoiding pelvic bones and organs. Laparotomy aimed at lysing bowel adhesions, placement of omental carpet, and refining needle placement. Postimplantation CT was used for loading optimization and dose evaluation. RESULTS: Catheter angles 15-25 degrees were found to adequately implant anteriorly laying targets while avoiding pubic bones and bladder. Adhesiolysis of bowel loops from the vaginal apex was required in patients with prior hysterectomy. Small modifications in catheter placements were made during laparotomy in all implants. Postimplantation CTs showed deviations of the catheter positions compared with the planning CTs and were essential in determining target and organ doses and loading optimization. At a median follow-up of 42 months (range: 9-80 months), local control rate is 55% and disease-free survival 40%. Late complications occurred in 2 of 11 of patients without local recurrence. CONCLUSIONS: CT-based planning, loading optimization, and dose evaluation of customized implants improve radiation dose delivery. Laparotomy enhances implant accuracy and safety. Local tumor control rate is still unsatisfactory. It reflects the shortcomings of technical advances alone in poor prognosis tumors like those selected for this series.

Temperature-dependent binding of hydrophilic beta-adrenergic receptor ligands to intact human lymphocytes.

Important differences in binding characteristics between agonists and antagonists of the beta-adrenergic receptor have been described. However, these observations have been complicated since most available antagonists are much more lipophilic than agonists. In order to separate out those binding characteristics of agonist vs. antagonist from those characteristics of lipophilic vs. hydrophilic ligands, we have studied competition of the hydrophilic ligands isoproterenol (agonist) and CGP-12177 (antagonist) with [125I]iodopindolol binding in intact human lymphocytes. Analyzing competition curves from assays performed at 13 degrees C, 25 degrees C and 37 degrees C we demonstrated that at lower temperatures there was a decrease in IC50 for isoproterenol but not for CGP-12177. Using cells preincubated with isoproterenol then extensively washed, competition curves with both isoproterenol and CGP-12177 were biphasic, and characterized by the appearance of a population of receptors with a low affinity for both hydrophilic ligands. Furthermore, at lower temperatures the biphasic nature of these curves was accentuated and was characterized by a 6-fold and 40-fold increase in the apparent KD of a population of low affinity sites for isoproterenol and CGP-12177, respectively.