Dietary and physical activity behaviors among adults successful at weight loss maintenance

Background  

There is limited population-based data on behavioral factors found to be important for successful weight loss maintenance among adults.     

Combined effects of tri-n-butyl tin (TBT) and diuron on marine periphyton communities detected as pollution-induced community tolerance

The effects of combined toxicity were studied, using marine periphyton communities exposed to mixtures of tri-n-butyl tin (TBT) and diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea, DCMU) in indoor aquaria during four weeks. The experimental design of the study followed a central composite design (CCD) and utilized dose-response surface methodology for evaluation of the results. The detection of pollution-induced community tolerance (PICT) was accomplished by short-term (1 h) tests on inhibition of photosynthesis. Both single-toxicant and two-toxicant short-term tests were used. Two tentative measures of tolerance are proposed to achieve convenient comparisons of the tolerances from the two-toxicant tests. With the detection of PICT, effects of the long-term exposure were recorded on diatom species richness, chlorophyll a accumulation and copepod abundance. The decrease of diatom species richness was accompanied by an increased tolerance (PICT), which was detectable by all tolerance measures used. Primary effects on microalgae were recorded as a decrease in chlorophyll a at higher toxicant concentrations. At lower concentrations, primary effects on copepods were found, which resulted in reduced grazing and increased chlorophyll a content.     

Modern Management of Chronic Myelogenous Leukemia (CML)

INTRODUCTION In the untreated state, patients with chronic myelogenous leukemia (CML) generally are asymptomatic and do not require urgent or intensive therapy. Resolution of the signs and symptoms of the disease using standard therapies is achievable without significant toxicity or risk to the patient. However, unlike acute myelogenous leukemia (AML), where true remissions can be obtained, in CML, despite attaining “hematologic” remission, persistence of the abnormal malignant clone as evidenced by the presence of the Philadelphia chromosome-positive (Ph+) cells is characteristic. Eventually all patients with CML, despite control of their disease in the chronic state, will enter a blastic or terminal phase resembling acute leukemia which, for the most part, is resistant to therapy. Patients with CML can expect a median survival of approximately 36-40 months (1) which has not changed appreciably in the last five decades. The recognition of this has led to the pursuit of more aggressive therapy using chemotherapy, immunotherapy, and chemoradiotherapy with marrow transplantation. This review focuses on the treatment of CML in the chronic phase, the use of aggressive therapy to obtain true remission and possible cure, and the therapeutic options available to patients who have entered the blastic phase.     

Expression of the c-myc, c-fos and c-rasHa protooncogenes during sex-differentiated rat liver carcinogenesis in the resistant hepatocyte model

The expression of the protooncogenes c-myc, c-fos and c-rasHa has been studied in rats treated according to the resistant hepatocyte model. Protooncogene expression was studied in male and female rat liver during the selection phase, when the outgrowth of putative preneoplastic foci/nodules is markedly faster in males, and compared with the expression in advanced nodules and hepatocellular carcinomas in males. During the first 16 h after partial hepatectomy the expression of c-fos and c-myc showed transient, 2- to 3-fold, increases in both sexes, both in initiated and in 'control' animals, receiving the selection/promotion regiment but no diethylnitrosamine, with a maximum at 0.5 and 2-4 h respectively. c-rasHa exhibited a moderate increase (1.5-fold) at 16-24 h in all groups. A second increase in c-myc expression (2-fold) started 24 h after partial hepatectomy and lasted over the entire selection period in initiated males, while it was unchanged in females and uninitiated males. The c-fos expression also showed a short-lived increase 24 h post partial hepatectomy in initiated males. The expression of c-myc and c-fos was increased 2- to 4-fold in both preneoplastic nodules and hepatocellular carcinomas, whereas c-rasHa expression was unchanged. In conclusion, sex differences were observed in the expression of c-myc and c-fos during the early outgrowth of preneoplastic lesions, possibly reflecting a connection between the expression of these genes and the sex differentiated response to promotion in the resistant hepatocyte model. Furthermore, an overexpression also in later stages of liver carcinogenesis might indicate that expression of the protooncogenes in question is related to the entire process of multistep carcinogenesis in this model.     

Selective transcatheter ablation of the fast and slow pathways using radiofrequency energy in patients with atrioventricular nodal reentrant tachycardia.

BACKGROUND. The safety and efficacy of selective fast versus slow pathway ablation using radiofrequency energy and a transcatheter technique in patients with atrioventricular nodal reentrant tachycardia (AVNRT) were evaluated. METHODS AND RESULTS. Forty-nine consecutive patients with symptomatic AVNRT were included. There were 37 women and 12 men (mean age, 43 +/- 20 years). The first 16 patients underwent a fast pathway ablation with radiofrequency current applied in the anterior/superior aspect of the tricuspid annulus. The remaining 33 patients initially had their slow pathway targeted at the posterior/inferior aspect of the right interatrial septum. The fast pathway was successfully ablated in the initial 16 patients and in three additional patients after an unsuccessful slow pathway ablation. A mean of 10 +/- 8 radiofrequency pulses were delivered; the last (successful) pulse was at a power of 24 +/- 7 W for a duration of 22 +/- 15 seconds. Four of these 19 patients developed complete atrioventricular (AV) block. In the remaining 15 patients, the post-ablation atrio-His intervals prolonged from 89 +/- 30 to 138 +/- 43 msec (p less than 0.001), whereas the shortest 1:1 AV conduction and effective refractory period of the AV node remained unchanged. Ten patients lost their ventriculoatrial (VA) conduction, and the other five had a significant prolongation of the shortest cycle length of 1:1 VA conduction (280 +/- 35 versus 468 +/- 30 msec, p less than 0.0001). Slow pathway ablation was attempted initially in 33 patients and in another two who developed uncommon AVNRT after successful fast pathway ablation. Of these 35 patients, 32 had no AVNRT inducible after 6 +/- 4 radiofrequency pulses with the last (successful) pulse given at a power of 36 +/- 12 W for a duration of 35 +/- 15 seconds. After successful slow pathway ablation, the shortest cycle length of 1:1 AV conduction prolonged from 295 +/- 44 to 332 +/- 66 msec (p less than 0.0005), the AV nodal effective refractory period increased from 232 +/- 36 to 281 +/- 61 msec (p less than 0.0001), and the atrio-His interval as well as the shortest cycle length of 1:1 VA conduction remained unchanged. No patients developed AV block. Among the last 33 patients who underwent a slow pathway ablation as the initial attempt and a fast pathway ablation only when the former failed, 32 (97%) had successful AVNRT abolition with intact AV conduction. During a mean follow-up of 6.5 +/- 3.0 months, none of the 49 patients had recurrent tachycardia. Forty patients had repeat electrophysiological studies 4-8 weeks after their successful ablation, and AVNRT could not be induced in 39 patients. CONCLUSIONS. These data suggest that both fast and slow pathways can be selectively ablated for control of AVNRT. Slow pathway ablation, however, by obviating the risk of AV block, appears to be safer and should be considered as the first approach.     

Genetic variation in cytochrome P-450 and xenobiotic metabolism in Drosophila melanogaster

A marked genetic variation in the capacity to perform xenobiotic metabolism was observed in microsomal fractions from the seven Drosophila strains studied. A 1,5 to 2-fold variation was found in the content of cytochrome P-450 and in the NADPH-cytochrome c reductase activity. The two insecticide-resistant strains Hikone R and Oregon R differed markedly when compared to sensitive strains by having a 3 to 17-fold higher p-nitroanisole (PNA) demethylase activity and biphenyl-3-hydroxylase activity. SDS-polyacrylamide gel electrophoresis of the microsomes also revealed an increased content of a protein band with an apparent mol. wt of 54,000 in the resistant strains. The 4-hydroxylation of biphenyl was also 2-7-fold higher in the Oregon R strain, and the band with a mol. wt of 56,000 had a higher protein content compared to the other strains. The biphenyl-4-hydroxylation was several-fold lower in the strain Berlin K. 2-OH-biphenyl was formed only in trace amounts by all strains. 7-Ethoxycoumarin (EC) deethylase activity and benzo(a)pyrene (BP) monooxygenase activity was 2-6-fold lower in the Hikone R strain. An increased amount of the protein with a mol. wt of 58,000 was noted in the Canton S strain. No concomitant increase in any enzyme activity was observed. A genetic variation between the strains was observed after phenobarbital (PB) treatment in the content of cytochrome P-450 and in the various enzyme activities, varying from non-responsiveness to a 4- to 5-fold increase. Aroclor 1254 (PCB) was less efficient in enhancing the activities. It caused maximally a 3-fold increase, had often no effect and in some cases even decreased the metabolism. beta-naphthoflavone (BNF) caused only marginal increases in the activities in most strains. The only significant effects were an increased formation of 3-OH-biphenyl in Berlin K and an enhanced NADPH-cytochrome c reductase activity in Lausanne-S. In conclusion, the variations observed in this study provide a basis for further studies on the genetic regulation of the cytochrome P-450 system in Drosophila. Furthermore, similarities in the regulation when compared to mammals indicate that studies on this genetically well characterized organism might contribute to the general understanding of the genetics of xenobiotic metabolism.     

Dietary energy density is associated with energy intake and weight status in US adults

BACKGROUND: Laboratory-based investigations indicate that the consumption of foods with a low energy density (kcal/g) decreases energy intake. Although low-energy-dense diets are recommended for weight management, relations between energy density, energy intake, and weight status have not been clearly shown in free-living persons. OBJECTIVES: A representative US sample was used to determine whether dietary energy density is associated with energy intake, the weight of food consumed, and body weight and to explore the influence of food choices (fruit, vegetable, and fat consumption) on energy density and body weight. DESIGN: A cross-sectional survey of adults (n = 7356) from the 1994-1996 Continuing Survey of Food Intakes by Individuals and two 24-h dietary recalls were used. RESULTS: Men and women with a low-energy-dense diet had lower energy intakes (approximately 425 and 275 kcal/d less, respectively) than did those with a high-energy-dense diet, even though they consumed more food (approximately 400 and 300 g/d more, respectively). Normal-weight persons had diets with a lower energy density than did obese persons. Persons with a high fruit and vegetable intake had the lowest energy density values and the lowest obesity prevalence. CONCLUSIONS: Adults consuming a low-energy-dense diet are likely to consume more food (by weight) but to have a lower energy intake than do those consuming a higher-energy-dense diet. The energy density of a variety of dietary patterns, including higher-fat diets, can be lowered by adding fruit and vegetables. Our findings support the hypothesis that a relation exists between the consumption of an energy-dense diet and obesity and provide evidence of the importance of fruit and vegetable consumption for weight management.