Citations

ABSTRACT Mycobacterium peregrinum consists of two taxa: types I and II. We evaluated 43 clinical type II strains from throughout the United States. They were responsible for soft-tissue and bone infections, catheter-related infections, and possible pneumonitis. By carbohydrate utilization, they were indistinguishable from type I strains, being d -mannitol and trehalose positive. However, they had a distinct susceptibility pattern that included intermediate ciprofloxacin MICs but low clarithromycin and doxycycline MICs of ≤1 μg/ml. These features were also shared by reference isolates of Mycobacterium senegalense from African bovine cases of “farcy.” By 16S rRNA gene sequencing, the type II isolates shared 100% sequence identity with M. senegalense . Partial sequencing of the type II hsp65 gene (441 bp) revealed four sequevars showing ≥98.4% identity with each other and ≥98.6% identity with the sequence of five bovine strains of M. senegalense . There was ≤97.1% identity with M. peregrinum type I isolates and other Mycobacterium fortuitum group species. Sequencing of additional gene targets including the 16S-23S rDNA internal transcribed spacer region and the rpoB gene (partial sequence) revealed a similar phylogenetic grouping. DNA-DNA hybridization showed 76 to 99% relatedness between the bovine and human strains. These studies demonstrate that type II isolates are not isolates of M. peregrinum but represent human strains of M. senegalense . This study is the first to demonstrate this species as a human pathogen. Representative human M. senegalense strains include ATCC 35755 and newly submitted strains ATCC BAA-849, ATCC BAA-850, and ATCC BAA-851.

Abstract Polychlorinated biphenyls (PCB) have been suspected as possible contributors to increasing non-Hodgkin's lymphoma incidence during the latter half of the 20th century based on their toxicologic properties and provocative epidemiologic reports. We investigated PCBs and other organochlorines and risk of non-Hodgkin's lymphoma in a population-based case-control study in the United States. Congeners of PCBs (including coplanar congeners), dioxins, furans and pesticides or pesticide metabolites were measured in plasma of 100 untreated cases and 100 control subjects. We used a multiple imputation procedure to fill in missing values of levels determined to be below the detection limits. Risks of non-Hodgkin's lymphoma associated with each analyte were estimated using conditional logistic regression for the continuous measure, exposure quartiles, trend across quartile categories, and exposures above the 95th percentile. Certain PCB congeners were associated with increased risk of non-Hodgkin's lymphoma, including coplanar PCBs 156, 180, and 194, with odds ratios for the highest versus lowest quartile ranging from 2.7 to 3.5, and significant trends. Each of the furan congeners was associated with risk of non-Hodgkin's lymphoma, as were total furans, with 3.5-fold increased risk for the highest versus lowest quartile and a significant trend across quartiles (P = 0.006). The toxic equivalency quotient (TEQ), a summed metric that weights congeners by their dioxin-like potency, was associated with non-Hodgkin's lymphoma, with 35% increased risk per 10 TEQ pg/g lipid (95% confidence interval, 1.02-1.79). Our results add to existing literature, which suggests that exposure to organochlorines contributes to non-Hodgkin's lymphoma risk; these risks were most apparent for certain PCBs and furans.

Abstract Aromatase [cytochrome P450 19 (CYP19)] is a critical enzyme for estrogen biosynthesis, and aromatase inhibitors are of increasing importance in the treatment of breast cancer. We set out to identify and characterize genetic polymorphisms in the aromatase gene, CYP19, as a step toward pharmacogenomic studies of aromatase inhibitors. Specifically, we “resequenced” all coding exons, all upstream untranslated exons plus their presumed core promoter regions, all exon-intron splice junctions, and a portion of the 3′-untranslated region of CYP19 using 240 DNA samples from four ethnic groups. Eighty-eight polymorphisms were identified, resulting in 44 haplotypes. Functional genomic studies were done with the four nonsynonymous coding single nucleotide polymorphisms (cSNP) that we observed, two of which were novel. Those cSNPs altered the following amino acids: Trp39Arg, Thr201Met, Arg264Cys, and Met364Thr. The Cys264, Thr364, and double variant Arg39Cys264 allozymes showed significant decreases in levels of activity and immunoreactive protein when compared with the wild-type (WT) enzyme after transient expression in COS-1 cells. A slight decrease in protein level was also observed for the Arg39 allozyme, whereas Met201 displayed no significant changes in either activity or protein level when compared with the WT enzyme. There was also a 4-fold increase in apparent Km value for Thr364 with androstenedione as substrate. Of the recombinant allozymes, only the double mutant (Arg39Cys264) displayed a significant change from the WT enzyme in inhibitor constant for the aromatase inhibitors exemestane and letrozole. These observations indicate that genetic variation in CYP19 might contribute to variation in the pathophysiology of estrogen-dependent disease.

Abstract Transforming growth factor-β (TGF-β) stimulates cellular proliferation and transformation to a myofibroblast phenotype in vivo and in a subset of fibroblast cell lines. As the Smad pathway is activated by TGF-β in essentially all cell types, it is unlikely to be the sole mediator of cell type–specific outcomes to TGF-β stimulation. In the current study, we determined that TGF-β receptor signaling activates phosphatidylinositol 3-kinase (PI3K) in several fibroblast but not epithelial cultures independently of Smad2 and Smad3. PI3K activation occurs in the presence of dominant-negative dynamin and is required for p21-activated kinase-2 kinase activity and the increased proliferation and morphologic change induced by TGF-β in vitro.

Purpose Individuals whose diabetes is being treated in the outpatient setting via an insulin pump often wish to maintain this therapy during hospitalization. The authors propose guidelines for management of patients on insulin pumps who require a hospital admission. Methods A collaborative interinstitutional task force reviewed current available information regarding the use of insulin pumps in the hospital. Results There was little information in the medical literature on how to manage individuals on established insulin pump therapy during a hospital stay. The task force believed that a policy that promotes patient independence through continuation of insulin pump therapy while ensuring patient safety was possible. A set of contraindications for continued use of pump therapy in the hospital are proposed. A sample patient consent form and order set are presented. Finally, measures that can be used to assess effectiveness of an inpatient insulin pump policy are outlined. Conclusions Patients on established insulin pump therapy do not necessarily have to discontinue treatment while hospitalized. However, clear policies and procedures should be established at the institutional level to guide continued use of the technology in the acute care setting.

Pulse pressure, the difference between systolic and diastolic blood pressure, is an independent risk factor for cardiovascular disease. Increased pulse pressure reflects reduced compliance of arteries and is a marker of atherosclerosis. To locate genes that affect pulse pressure, a genome-wide linkage scan for quantitative trait loci influencing pulse pressure was performed using variance components methods as implemented in sequential oligogenic linkage analysis routines. The analysis sample included 10 798 participants in 3320 families who were recruited as part of the Family Blood Pressure Program and were phenotyped with an oscillometric blood pressure measurement device using a consistent protocol across centers. Pulse pressure was adjusted for the effects of sex, age, age 2 , age-by-sex interaction, age 2 -by-sex interaction, body mass index, and field center to remove sources of variation other than the genetic effects related to pulse pressure. Significant linkage was observed on chromosome 18 (logarithm of odds [LOD]=3.2) in a combined racial sample, chromosome 20 (LOD=4.4), and 17 (LOD=3.6) in Hispanics, chromosome 21 (LOD=4.3) in whites, chromosome 19 (LOD=3.1) in a combined sample of blacks and whites, and chromosome 7 (logarithm of odds [LOD]=3.1) in blacks from the GenNet Network. Our genome scan shows significant evidence for linkage for pulse pressure in multiple areas of the genome, supporting previous published linkage studies. The identification of these loci for pulse pressure and the apparent congruence with other blood pressure phenotypes provide increased support that these regions contain genes influencing blood pressure phenotypes.

Abstract Deletion of phenylalanine 508 (ΔF508) accounts for nearly 70% of all mutations that occur in the cystic fibrosis transmembrane conductance regulator (CFTR). The ΔF508 mutation is a class II processing mutation that results in very little or no mature CFTR protein reaching the apical membrane and thus no cAMP-mediated Cl− conductance. Therapeutic strategies have been developed to enhance processing of the defective ΔF508 CFTR molecule so that a functional cAMP-regulated Cl− channel targets to the apical membrane. Sarcoplasmic/endoplasmic reticulum calcium (SERCA) inhibitors, curcumin and thapsigargin, have been reported to effectively correct the CF ion transport defects observed in the ΔF508 CF mice. We investigated the effect of these compounds in human airway epithelial cells to determine if they could induce ΔF508 CFTR maturation, and Cl− secretion. We also used Baby Hamster Kidney cells, heterologously expressing ΔF508 CFTR, to determine if SERCA inhibitors could interfere with the interaction between calnexin and CFTR and thereby correct the ΔF508 CFTR misfolding defect. Finally, at the whole animal level, we tested the ability of curcumin and thapsigargin to (1) induce Cl− secretion and reduce hyperabsorption of Na+ in the nasal epithelia of the ΔF508 mouse in vivo, and (2) induce Cl− secretion in intestine (jejunum and distal colon) and the gallbladder of the ΔF508 CF mouse. We conclude that curcumin and thapsigargin failed to induce maturation of ΔF508 CFTR, or induce Cl− secretion, as measured by biochemical and electrophysiologic techniques in a variety of model systems ranging from cultured cells to in vivo studies.

Purpose A traditional end point for colon adjuvant clinical trials is overall survival (OS), with 5 years demonstrating adequate follow-up. A shorter-term end point providing convincing evidence to allow treatment comparisons could significantly speed the translation of advances into practice. Methods Individual patient data were pooled from 18 randomized phase III colon cancer adjuvant clinical trials. Trials included 43 arms, with a pooled sample size of 20,898 patients. The primary hypothesis was that disease-free survival (DFS), with 3 years of follow-up, is an appropriate primary end point to replace OS with 5 years of follow-up. Results The recurrence rates for years 1 through 5 were 12%, 14%, 8%, 5%, and 3%, respectively. Median time from recurrence to death was 12 months. Eighty percent of recurrences were in the first 3 years; 91% of patients with recurrence by 3 years died before 5 years. Correlation between 3-year DFS and 5-year OS was 0.89. Comparing control versus experimental arms within each trial, the correlation between hazard ratios for DFS and OS was 0.92. Within-trial log-rank testing using both DFS and OS provided the same conclusion in 23 (92%) of 25 cases. Formal measures of surrogacy were satisfied. Conclusion In patients treated on phase III adjuvant colon clinical trials, DFS and OS are highly correlated, both within patients and across trials. These results suggest that DFS after 3 years of median follow-up is an appropriate end point for adjuvant colon cancer clinical trials of fluorouracil-based regimens, although marginally significant DFS improvements may not translate into significant OS benefits.

Background and Purpose— Mitral annular calcification (MAC) and aortic valve (AV) sclerosis have each been linked to cardiovascular disease. Whether MAC and AV sclerosis are risk factors for stroke independent of other echocardiographic or laboratory predictors has not been established. We evaluated the relationship between MAC, AV sclerosis, and first stroke events in a population-based cohort. Methods— Our study cohort consisted of 2723 American Indians participating in the Strong Heart Study who were free of prevalent cardiovascular disease. Participants underwent standardized clinical, echocardiographic, and laboratory evaluation, and incident stroke was ascertained using validated methods. Results— During a median follow-up of 7 years, 86 strokes occurred. Age- and sex-adjusted incidence rates of stroke were significantly increased for MAC (rate ratio [RR], 3.12; 95% CI, 1.77 to 5.25) but not for AV sclerosis (RR, 1.15; 95% CI, 0.45 to 2.49). MAC was also associated with a reduced time to first stroke events after adjustment for clinical variables and the inflammatory markers C-reactive protein and fibrinogen (hazard ratio [HR], 2.42; 95% CI, 1.39 to 4.21) or the echocardiographic covariates left ventricular hypertrophy and left atrial enlargement (HR, 1.89; 95% CI, 1.04 to 3.41). Individuals with and without AV sclerosis showed no significant difference in stroke-free survival in unadjusted analyses ( P =0.698). Crossing of the survival curves precluded multivariable analysis using Cox models. Conclusions— In this cohort of American Indians without clinical cardiovascular disease, the presence of MAC, but not AV sclerosis, proved to be a strong risk factor for incident stroke after extensive adjustment for other predictors. Individuals exhibiting MAC may benefit from aggressive risk factor modification, but this will require further investigation.

Purpose Surgical resection of liver-only metastases from colorectal cancer has undergone extensive evaluation and review. The use of neoadjuvant chemotherapy to improve the likelihood of resection in disease that is not optimally resectable has not been as well studied. Patients and Methods Patients with liver-only metastases from colorectal cancer deemed not optimally resectable by a surgeon with expertise in liver surgery received fluorouracil, leucovorin, and oxaliplatin (FOLFOX4). Patients were periodically reassessed for resectability. Surgical response was classified as completely resectable (S-CR), partially resectable (S-PR), or unresectable (S-UR). Study design specified the accrual of 39 patients, with two or more S-CRs considered evidence of promising activity with respect to increasing the S-CR rate. Results Forty-two of 44 patients were assessable for this analysis. Twenty-five patients (60%) had tumor reduction by serial imaging. Seventeen patients (40%) underwent surgery (S-CR, n = 14; S-PR, n = 1; and S-UR, n = 2) after a median of 6 months of chemotherapy. With a median postsurgical follow-up of 22 months (range, 13 to 32 months), 11 recurrences have occurred in the 15 S-CR and S-PR patients. Median survival time was 26 months. Conclusion Our data suggest that FOLFOX4 has a high response rate (complete response, partial response, or reduction) in patients with liver-only metastases from colorectal cancer, allowing for successful resection of disease in a portion of patients initially not judged to be optimally resectable. However, a high recurrence rate after surgery was observed, which, in 73% of patients, involved the liver. Further trials are indicated based on the promising results observed in this trial.