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D L Barton

Publications and source records attributed to D L Barton.

14 recordsLinked to original sources
PubMed2001

Methodologic lessons learned from hot flash studies.

PURPOSE: In the course of conducting a series of prospective clinical trials devoted to defining new treatment opportunities for hot flashes in cancer survivors, considerable experience has been acquired with related methodologic issues. This article has been written in response to many queries regarding this methodology. PATIENTS AND METHODS: A series of seven different clinical trials that involved 968 patients was used for this work. Reliable and valid definitions of hot flash intensity were developed from patient-reported descriptions. Concomitant validity and reliability assessment of patient-completed diaries was undertaken to compare hot flash data with toxicity and quality-of-life (QOL) end points and to examine consistency across patient groups using variability analysis and correlation procedures. Parametric data from this meta-analysis was used to examine relative power considerations for the design of phase II and phase III clinical trials. RESULTS: Daily diaries used in these studies exhibited consistency and reliability and had few missing data. Hot flash frequency and hot flash score (frequency multiplied by average severity) variables produced almost identical end point results. For phase III placebo-controlled studies, 50 patients per treatment arm seem appropriate to provide sufficient power specifications to detect a clinically meaningful change in hot flash activity. For phase II trials, 25 patients per trial seem to provide reasonable estimates of eventual hot flash efficacy to screen potential agents for more definitive testing. CONCLUSION: Given the data gained from these experiences, we can plan and carry out more efficient trials to identify efficacious agents for the reduction of hot flash activity.

Analysis of Variance↗
PubMed2001

Management of hot flashes in breast-cancer survivors.

Hot flashes can be a major problem for patients with a history of breast cancer. Although oestrogen can alleviate hot flashes to a large extent in most patients, there has been debate about the safety of oestrogen use in survivors of breast cancer. The decrease in hot flashes achieved with progestational agents is similar to that seen with oestrogen therapy but, again, there is some debate about the safety of progestational agents in patients with a history of breast cancer. Several alternative substances have therefore been investigated. These include a belladonna alkaloid preparation, clonidine, soy phyto-oestrogens, vitamin E, gabapentin, and several of the newer antidepressants, with venlafaxine being the best studied to date. Several studies in progress may provide better non-hormonal means of treating hot flashes in the future.

Antidepressive Agents↗
PubMed2001

Seed-specific over-expression of an Arabidopsis cDNA encoding a diacylglycerol acyltransferase enhances seed oil content and seed weight.

We recently reported the cloning and characterization of an Arabidopsis (ecotype Columbia) diacylglycerol acyltransferase cDNA (Zou et al., 1999) and found that in Arabidopsis mutant line AS11, an ethyl methanesulfonate-induced mutation at a locus on chromosome II designated as Tag1 consists of a 147-bp insertion in the DNA, which results in a repeat of the 81-bp exon 2 in the Tag1 cDNA. This insertion mutation is correlated with an altered seed fatty acid composition, reduced diacylglycerol acyltransferase (DGAT; EC 2.3.1.20) activity, reduced seed triacylglycerol content, and delayed seed development in the AS11 mutant. The effect of the insertion mutation on microsomal acyl-coenzyme A-dependent DGAT is examined with respect to DGAT activity and its substrate specificity in the AS11 mutant relative to wild type. We demonstrate that transformation of mutant AS11 with a single copy of the wild-type Tag1 DGAT cDNA can complement the fatty acid and reduced oil phenotype of mutant AS11. More importantly, we show for the first time that seed-specific over-expression of the DGAT cDNA in wild-type Arabidopsis enhances oil deposition and average seed weight, which are correlated with DGAT transcript levels. The DGAT activity in developing seed of transgenic lines was enhanced by 10% to 70%. Thus, the current study confirms the important role of DGAT in regulating the quantity of seed triacylglycerols and the sink size in developing seeds.

Acyl Coenzyme A↗
PubMed2000

Venlafaxine in management of hot flashes in survivors of breast cancer: a randomised controlled trial.

BACKGROUND: Hot flashes can be troublesome, especially when hormonal therapy is contraindicated. Preliminary data have suggested that newer antidepressants, such as venlafaxine, can diminish hot flashes. We undertook a double-blind, placebo-controlled, randomised trial to assess the efficacy of venlafaxine in women with a history of breast cancer or reluctance to take hormonal treatment because of fear of breast cancer. METHODS: Participants were assigned placebo (n=56) or venlafaxine 37.5 mg daily (n=56), 75 mg daily (n=55), or 150 mg daily (n=54). After a baseline assessment week, patients took the study medication for 4 weeks. All venlafaxine treatment started at 37.5 mg daily and gradually increased in the 75 mg and 150 mg groups. Patients completed daily hot-flash questionnaire diaries. The primary endpoint was average daily hot-flash activity (number of flashes and a score combining number and severity). Analyses were based on the women who provided data throughout the baseline and study weeks. FINDINGS: 191 patients had evaluable data for the whole study period (50 placebo, 49 venlafaxine 37.5 mg, 43 venlafaxine 75 mg, 49 venlafaxine 150 mg). After week 4 of treatment, median hot flash scores were reduced from baseline by 27% (95% CI 11-34), 37% (26-54), 61% (50-68), and 61% (48-75) in the four groups. Frequencies of some side-effects (mouth dryness, decreased appetite, nausea, and constipation) were significantly higher in the venlafaxine 75 mg and 150 mg groups than in the placebo group. INTERPRETATION: Venlafaxine is an effective non-hormonal treatment for hot flashes, though the efficacy must be balanced against the drug's side-effects. Confirmation of the results of this 4-week study awaits the completion of three ongoing randomised studies to assess the effects of other related antidepressants for the treatment of hot flashes.

Antidepressive Agents, Second-Generation↗
PubMed2000

The plastidic phosphoglucomutase from Arabidopsis. A reversible enzyme reaction with an important role in metabolic control.

An Arabidopsis cDNA (AtPGMp) encoding the plastidic phosphoglucomutase (PGM) predicted a 623-amino acid protein with an N-terminal sequence typical of a plastid signal peptide. Expression of a recombinant protein in Escherichia coli confirmed its enzyme activity. The recombinant enzyme had an apparent K(m) value of 98.5 microM and a V(max) of 4.48 micromol min(-1) (mg protein)(-1). The Calvin cycle intermediates fructose-1,6-bisphosphate and ribulose-1, 5-bisphosphate exerted an inhibitory effect on PGM activity, supporting its proposed involvement in controlling photosynthetic carbon flow. A point mutation was identified in the AtPGMp gene of the Arabidopsis pgm-1 mutant. The mutation in the mutant transcript generated a stop codon at about one third of the wild-type open reading frame, and thus rendered the polypeptide nonfunctional. Storage lipid analysis of the pgm-1 mutant seeds showed a 40% reduction in oil content compared with that of wild type. Our results indicate that plastidic PGM is an important factor affecting carbon flux in triacylglycerol accumulation in oilseed plants, most likely through its essential role in starch synthesis.

Amino Acid Sequence↗
PubMed2000

Sex differences in fluorouracil-induced stomatitis.

PURPOSE: A meta-analysis of six North Central Cancer Treatment Group (NCCTG) trials involving patients receiving their first ever fluorouracil (5-FU)-based chemotherapy was undertaken to explore the association of sex with reports of the incidence and severity of stomatitis. PATIENTS AND METHODS: Data were obtained on a total of 731 patients (402 men and 329 women). Comparisons of incidence and severity rates and average stomatitis across sex were performed using standard binomial testing and t tests, respectively. Logistic regression analysis and a weighted analysis using data summarized to study level served as evidence of cross-validation. RESULTS: Women reported stomatitis both more often and with greater severity than did men. The incidence of any stomatitis for women was 63% versus 52% for men (P =.002). The incidence of severe or very severe stomatitis for men and women was 22% and 12%, respectively (P =. 0006). On average, women reported stomatitis of roughly 0.4 points higher than men on a 0 to 4 ordinal scale (P <.00001). Comparison of results across treatment and placebo arms was carried out to validate the initial findings. Logistic regression modelling further confirmed the results conditional on the presence of a number of potentially confounding covariates. Women were also 11% more likely than men to experience leukopenia of common toxicity criteria grade >/= 1, (70% v 59%, respectively; P <.00001) and grade 3+ (18% v 11%, respectively; P =.004). CONCLUSION: More women than men reported 5-FU-induced stomatitis. The precise mechanism resulting in different degrees of stomatitis across sex is not evident.

Adult↗
PubMed2000

Evaluation of soy phytoestrogens for the treatment of hot flashes in breast cancer survivors: A North Central Cancer Treatment Group Trial.

PURPOSE: Hot flashes represent a significant clinical problem for some breast cancer survivors. Safe, effective treatment is needed for this prominent clinical problem. Although it has been shown that estrogen or progesterone replacement therapy can alleviate this problem, there are continued safety concerns regarding the use of hormonal therapies in these women. Based on anecdotal information, we hypothesized that soy-derived phytoestrogens, weak estrogen-like substances in the soybean that demonstrate estrogen agonist and/or antagonist effects when they bind to estrogen receptors, could alleviate hot flashes. This current trial was designed to investigate this hypothesis. PATIENTS AND METHODS: This double-blind clinical trial involved breast cancer survivors with substantial hot flashes. After randomization, patients underwent a 1-week baseline period with no therapy. This was followed by 4 weeks of either soy tablets or placebo. The patients then crossed over to the opposite arm in a double-blind manner for the last 4 weeks. Patients completed a daily questionnaire documenting hot flash frequency, intensity, and perceived side effects. RESULTS: Of the 177 women who were randomized and started the study substance, 155 (88%) provided useable data over the first 5 weeks; 149 provided usable data over the entire 9 weeks. There was no suggestion that the soy product was more effective in reducing hot flashes than the placebo. At study completion, patients preferred the soy product 33% of the time, the placebo 37% of the time, and neither substance 31% of the time. No toxicity was observed. CONCLUSION: The soy product did not alleviate hot flashes in breast cancer survivors.

Adolescent↗
PubMed2000

Utility of the Arabidopsis FAE1 and yeast SLC1-1 genes for improvements in erucic acid and oil content in rapeseed.

High-erucic acid (HEA) Brassica napus cultivars are regaining interest in industrial contexts. Erucic acid and its derivatives are important renewable raw materials utilized in the manufacture of plastic films, in the synthesis of Nylon 13,13, and in the lubricant and emollient industries. Theoretically, the highest level of erucic acid that can be achieved by means of classical breeding is 66 mol%; however, using new approaches on the basis of genetic engineering, it might be possible to develop a B. napus cultivar containing levels of erucic acid significantly above 66 mol% (>80 mol%). In an attempt to increase the amounts of very-long-chain fatty acids (VLCFAs), and erucic acid in particular, in Canadian HEA B. napus cultivars, we have focused on two targets using a transgenic approach. We examined both the role/function of the Arabidopsis thaliana FAE1 (fatty acid elongase) gene by expressing it under the control of the seed-specific napin promoter in B. napus germplasm with analysis of the changes in VLCFA content in the seed oil of transgenic lines, and the performance of the yeast SLC1-1 (sphingolipid compensation mutant) in B. napus cv. Hero transgenic progeny in the field. Here, we report analyses of the contents of 22:1, total VLCFAand oil in the seed oil, as well as seed yield of the field-grown FAE1 and SLC1-1 B. napus cv. Hero progeny.

Acetyltransferases↗
PubMed1998

Definitions of hot flashes in breast cancer survivors.

Menopause is an expected event in a woman's life. Treatment for breast cancer can impact the onset of menopause and precipitate symptoms such as hot flashes. Yet this sequelae of events is not well measured, defined or assimilated into quality of life assessments for cancer survivors. Though not life threatening, hot flashes can greatly impact a woman's quality of life or functional ability. It is important for health care professionals to more fully understand the nature of the experience of hot flashes so as not to underestimate their disruptive potential. As part of a larger clinical trial to look at the effectiveness of vitamin E for hot flashes, breast cancer survivors kept a log of both the frequency and intensity of their hot flashes. These women then wrote descriptions to define the severity of those hot flashes. The purpose of this paper is to provide insight into the experience of hot flashes in breast cancer survivors and to describe the severity of hot flashes with narratives given by the women experiencing them.

Adult↗
PubMed1998

Prospective evaluation of vitamin E for hot flashes in breast cancer survivors.

PURPOSE: Hot flashes represent a substantial clinical problem for some breast cancer survivors. Although estrogen or progesterone preparations can alleviate these symptoms in many patients, concern remains regarding the use of hormonal preparations in such women. Thus, there is a perceived need for nonhormonal treatments for hot flashes for breast cancer survivors. Based on anecdotal evidence that vitamin E was helpful, we designed a trial to investigate this matter. METHODS: We developed and conducted a placebo-controlled, randomized, crossover trial where, after a 1 week baseline period, patients received 4 weeks of vitamin E 800 IU daily, then 4 weeks of an identical-appearing placebo, or vice versa. Diaries were used to measure potential toxicities and hot flashes during the baseline week and the two subsequent 4-week treatment periods. RESULTS: The 120 patients evaluated for toxicity failed to show any. The 105 patients who finished the first treatment period showed a similar reduction in hot flash frequencies (25% v 22%; P = .90) for the two study arms. A crossover analysis, however, showed that vitamin E was associated with a minimal decrease in hot flashes (one less hot flash per day than was seen with a placebo) (P < or = .05). At the study end, patients did not prefer vitamin E over the placebo (32% v 29%, respectively). CONCLUSION: Although this trial was able to show a statistically significant hot flash reduction with vitamin E compared to a placebo, the clinical magnitude of this reduction was marginal.

Adolescent↗
PubMed1997

Modification of seed oil content and acyl composition in the brassicaceae by expression of a yeast sn-2 acyltransferase gene.

A putative yeast sn-2 acyltransferase gene (SLC1-1), reportedly a variant acyltransferase that suppresses a genetic defect in sphingolipid long-chain base biosynthesis, has been expressed in a yeast SLC deletion strain. The SLC1-1 gene product was shown in vitro to encode an sn-2 acyltransferase capable of acylating sn-1 oleoyl-lysophosphatidic acid, using a range of acyl-CoA thioesters, including 18:1-, 22:1-, and 24:0-CoAs. The SLC1-1 gene was introduced into Arabidopsis and a high erucic acid-containing Brassica napus cv Hero under the control of a constitutive (tandem cauliflower mosaic virus 35S) promoter. The resulting transgenic plants showed substantial increases of 8 to 48% in seed oil content (expressed on the basis of seed dry weight) and increases in both overall proportions and amounts of very-long-chain fatty acids in seed triacylglycerols (TAGs). Furthermore, the proportion of very-long-chain fatty acids found at the sn-2 position of TAGs was increased, and homogenates prepared from developing seeds of transformed plants exhibited elevated lysophosphatidic acid acyltransferase (EC 2.3.1.51) activity. Thus, the yeast sn-2 acyltransferase has been shown to encode a protein that can exhibit lysophosphatidic acid acyltransferase activity and that can be used to change total fatty acid content and composition as well as to alter the stereospecific acyl distribution of fatty acids in seed TAGs.

1-Acylglycerol-3-Phosphate O-Acyltransferase↗
PubMed1995

A randomized, crossover evaluation of methylphenidate in cancer patients receiving strong narcotics.

Sedation may be a dose-limiting side-effect of opioid therapy in some cancer patients. This study was designed to evaluate further the use of the psychostimulant, methylphenidate, an agent that has been reported to counter-act opioid-induced sedation, in patients with cancer-related pain. Patients receiving a stable dose of an opioid for cancer-related pain were recruited for this randomized, double-blind, crossover clinical trial. In addition to their regular dose of narcotics, they received 5 days of methylphenidate followed by 5 days of placebo, or vice versa. Our data did not definitively demonstrate any statistically significant benefit for methylphenidate, but did suggest that this drug could mildly decrease narcotic-induced drowsiness and could increase night-time sleep. These data, in conjunction with other published data, suggest that methylphenidate can counteract narcotic-induced daytime sedation to a limited degree.

Adolescent↗
PubMed1995

Alteration of seed fatty acid composition by an ethyl methanesulfonate-induced mutation in Arabidopsis thaliana affecting diacylglycerol acyltransferase activity.

In characterizing the enzymes involved in the formation of very long-chain fatty acids (VLCFAs) in the Brassicaceae, we have generated a series of mutants of Arabidopsis thaliana that have reduced VLCFA content. Here we report the characterization of a seed lipid mutant, AS11, which, in comparison to wild type (WT), has reduced levels of 20:1 and 18:1 and accumulates 18:3 as the major fatty acid in triacylglycerols. Proportions of 18:2 remain similar to WT. Genetic analyses indicate that the fatty acid phenotype is caused by a semidominant mutation in a single nuclear gene, designated TAG1, located on chromosome 2. Biochemical analyses have shown that the AS11 phenotype is not due to a deficiency in the capacity to elongate 18:1 or to an increase in the relative delta 15 or delta 12 desaturase activities. Indeed, the ratio of desaturase/elongase activities measured in vitro is virtually identical in developing WT and AS11 seed homogenates. Rather, the fatty acid phenotype of AS11 is the result of reduced diacylglycerol acyltransferase activity throughout development, such that triacylglycerol biosynthesis is reduced. This leads to a reduction in 20:1 biosynthesis during seed development, leaving more 18:1 available for desaturation. Thus, we have demonstrated that changes to triacylglycerol biosynthesis can result in dramatic changes in fatty acid composition and, in particular, in the accumulation of VLCFAs in seed storage lipids.

Acyltransferases↗