Citations

Abstract Thiopurine methyltransferase (TPMT) is an important enzyme in the metabolism of thiopurine medications such as azathioprine. In humans, activity varies widely among individuals, primarily because of genetic polymorphisms. Low TPMT activity increases the risk of myelosuppression from azathioprine and 6-mercaptopurine, whereas high TPMT activity is associated with poor drug efficacy. The purpose of this study was to determine whether dogs also show a wide range of TPMT activity. Heparinized blood samples were obtained from 177 dogs associated with a veterinary teaching hospital. Red blood cell (RBC) TPMT activity was measured by means of a modification of a radiochemical method as established for use in people. TPMT activity varied across a 9-fold range (7.9–71.8 U of RBC per milliliter; median, 21.7). Variation in TPMT activity was not associated with age, sex, or neutering status. Giant Schnauzers had much lower TPMT activity (7.9–20 U of RBC per milliliter; median, 13.1; P < .001) than did other breeds, and Alaskan Malamutes had much higher TPMT activity (22.7–71.8 U of RBC per milliliter; median, 36.0; P < .001) than did other breeds. Such variations in TPMT activity in the canine population and within groups of related dogs could affect thiopurine drug toxicity and efficacy in canine patients.

Background Often in randomized controlled trials of cancer screening, cause of death is determined by a mortality review committee. However, little is known regarding how findings from mortality review compare to those from death certificates alone. Purpose To examine the results of four different U. S. trials of cancer screening when death certificate data only were used, as compared to results using all available mortality review information. Methods Trials included were the Health Insurance Plan of New York breast screening trial (HIP), the Minnesota trial of fecal occult blood testing, and the Johns Hopkins and Mayo Lung Projects, which each examined chest x-ray and sputum cytology. The sensitivity, specificity, positive and negative predictive values, and Cohen’s kappa for death certificates were calculated for all arms of all trials. Separate intention-to-screen analyses were conducted for each trial using cause of death information from either death certificates alone or full mortality review data. Results Generally there was excellent agreement between the death certificates and the mortality review committee as to the underlying cause of death (kappa >0.85 in all cases); death certificate agreement was similar between arms in all trials. Modest changes in the screening effectiveness estimates were observed when mortality review information was utilized, ranging from a 9% decrease to a 2% increase in the calculated mortality rate ratios. However, in one instance (HIP) a statistically significant benefit of screening was observed when mortality review committee data were used (rate ratio (RR) 0.77, 95% confidence interval (CI) 0.62— 0.95) but not when death certificate data were used (RR 0.82, 95% CI 0.65—1.03). Limitations Although considered to be the gold standard, even carefully conducted mortality review may result in errors in cause of death assignment. Conclusions For each trial, results were similar regardless of the source of cause of death information. Clinical Trials 2010; 7: 69—77. http://ctj.sagepub.com

AbstractPursuing the hypothesis that quantitation of skeletal alkaline phosphatase (ALP) activity in canine serum would provide an index of the rate of bone formation, we compared three methods for isoenzyme-specific identification of skeletal ALP activity in canine serum: heat inactivation, wheat germ agglutinin (WGA) precipitation, and concanavalin A (ConA) precipitation. ALP isoenzyme activities were extracted from canine bone, intestine, and liver, diluted into heat-inactivated canine serum (i.e., serum without ALP activity), and used as calibrators of ALP isoenzyme activities. Differential sensitivity to inhibition by 10 mM L-homoarginine was used to distinguish intestinal ALP activity from hepatic and skeletal ALP activities (i.e., 9, 80, and 72% inhibition, respectively). To allow resolution of skeletal ALP activity from hepatic ALP activity, we tested two established methods (heat inactivation and WGA precipitation) and a novel method, ConA precipitation. The organ-derived skeletal and hepatic ALP isoenzyme activities were used to compare these three methods with respect to linearity, isoenzyme separation, and precision. All three methods were linear, but the WGA and ConA methods afforded greater isoenzyme separation and precision. The relative extent of isoenzyme separation (i.e., the difference in percentage remaining skeletal and hepatic ALP isoenzyme activities) averaged 23, 40, and 47% remaining ALP activity for the heat, WGA, and ConA methods, respectively. However, when these methods were applied to the quantitation of skeletal ALP activity in sera from 10 young and 10 adult beagles, the WGA method was found to be unacceptable because most of the results fell outside the range of the WGA assay calibrators (i.e., >100% skeletal ALP activity). The heat and ConA methods showed that the amount of skeletal ALP activity in the beagle sera decreased with age, both as ALP activity per liter and as percentage of total serum ALP activity (p < 0.001 for each). Skeletal ALP activity levels determined by ConA were correlated with values determined by heat inactivation (r = 0.87, p < 0.001) but not with WGA-determined levels (r = 0.26). Intestinal ALP activity was detected in only 1 of these 20 sera. We conclude that ConA precipitation can be used for quantitation of skeletal ALP activity in beagle serum.

Objective: There are no Food and Drug Administration (FDA)-approved medications indicated for the treatment of frontotemporal dementia (FTD). We sought to determine the most commonly used drugs used to treat behavioral variant FTD (bvFTD) in specialized dementia clinics. Methods: Medication and demographic data from the Alzheimer’s Disease Research Centers of California (ARCC) and a multicenter FTD natural history study (NHS) data set were compared in bvFTD and Alzheimer’s disease (AD), and effects of demographic variables were assessed using logistic regression. Results: Overall, the percentage of patients taking one or more FDA-approved AD or psychiatric medications was similar in bvFTD and AD; however, after controlling for demographic variables, acetylcholinesterase inhibitor (AChI) use was less common in bvFTD, whereas memantine use remained similar in the 2 groups. Conclusions: Despite lack of evidence for efficacy, the use of AChIs and memantine is common in bvFTD. Clinical trials should be pursued to determine the optimal therapeutic interventions for bvFTD.

OBJECTIVE: Despite the magnitude of the problem of catheter-associated bloodstream infections (CA-BSIs) in children, relatively little research has been performed to identify effective strategies to reduce these complications. In this study, we aimed to develop and evaluate effective catheter-care practices to reduce pediatric CA-BSIs. STUDY DESIGN AND METHODS: Our study was a multi-institutional, interrupted time-series design with historical control data and was conducted in 29 PICUs across the United States. Two central venous catheter–care practice bundles comprised our intervention: the insertion bundle of pediatric-tailored care elements derived from adult efforts and the maintenance bundle derived from the Centers for Disease Control and Prevention recommendations and expert pediatric clinician consensus. The bundles were deployed with quality-improvement teaching and methods to support their adoption by teams at the participating PICUs. The main outcome measures were the rate of CA-BSIs from January 2004 to September 2007 and compliance with each element of the insertion and maintenance bundles from October 2006 to September 2007. RESULTS: Average CA-BSI rates were reduced by 43% across 29 PICUs (5.4 vs 3.1 CA-BSIs per 1000 central-line-days; P < .0001). By September 2007, insertion-bundle compliance was 84% and maintenance-bundle compliance was 82%. Hierarchical regression modeling showed that the only significant predictor of an observed decrease in infection rates was the collective use of the insertion and maintenance bundles, as demonstrated by the relative rate (RR) and confidence intervals (CIs) (RR: 0.57 [95% CI: 0.45–0.74]; P < .0001). We used comparable modeling to assess the relative importance of the insertion versus maintenance bundles; the results showed that the only significant predictor of an infection-rate decrease was maintenance-bundle compliance (RR: 0.41 [95% CI: 0.20–0.85]; P = .017). CONCLUSIONS: In contrast with adult ICU care, maximizing insertion-bundle compliance alone cannot help PICUs to eliminate CA-BSIs. The main drivers for additional reductions in pediatric CA-BSI rates are issues that surround daily maintenance care for central lines, as defined in our maintenance bundle. Additional research is needed to define the optimal maintenance bundle that will facilitate elimination of CA-BSIs for children.

Abstract Aromatase (CYP19) is a critical enzyme in estrogen biosynthesis and aromatase inhibitors (AI) are employed widely for endocrine therapy in postmenopausal women with breast cancer. We hypothesized that single nucleotide polymorphisms (SNPs) in the CYP19 gene may alter the effectiveness of AI therapy in the neoadjuvant setting. Genomic DNA was obtained for sequencing from 52 women pre-AI and post-AI treatment in this setting. Additionally, genomic DNA obtained from 82 samples of breast cancer and 19 samples of normal breast tissue was subjected to resequencing. No differences in CYP19 sequence were observed between tumor and germ-line DNA in the same patient. A total of 48 SNPs were identified including 4 novel SNPs when compared with previous resequencing data. For genotype-phenotype association studies, we determined the levels of aromatase activity, estrone, estradiol, and tumor size in patients pre-AI and post-AI treatment. We defined two tightly linked SNPs (rs6493497 and rs7176005 in the 5'-flanking region of CYP19 exon 1.1) that were significantly associated with a greater change in aromatase activity after AI treatment. In a follow-up study of 200 women with early-stage breast cancer who were treated with adjuvant anastrozole, these same two SNPs were also associated with higher plasma estradiol levels in patients pre-AI and post-AI treatment. Electrophoretic mobility shift and reporter gene assays confirmed likely functional effects of these two SNPs on transcription of CYP19. Our findings indicate that two common genetic polymorphisms in the aromatase gene CYP19 vary the response of breast cancer patients to aromatase inhibitors. Cancer Res; 70(1); 319–28