211 resultados para Anabolic androgenic steroids - Chemotherapeutic treatment

em University of Queensland eSpace - Australia


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Interactions between testosterone, estradiol, and inhibin in the control of gonadotrophin secretion in males are poorly understood. Castrated rams were treated with steroid-free bovine follicular fluid (bFF), testosterone, or estradiol and for 7 d (2 x 2 x 2 factorial design). Given independently, none of the exogenous hormones affected follicle-stimulating hormone (FSH) concentrations, but the combination of one or both steroids with bFF reduced FSH secretion. Testosterone and estradiol reduced luteinizing hormone (LH) pulse frequency (there was no synergism), and bFF had no effect. Plasma prolactin concentrations were not affected by any treatment. To locate the central sites of steroid action, castrated rams were bilaterally implanted in the preoptic area (POA), ventromedial nucleus (VMH), or arcuate nucleus (ARC). These implants did not affect FSH or prolactin concentrations, or LH pulse amplitude. The frequency of the LH pulses was not affected by testosterone in any site. Estradiol located in the ARC, but not the POA or VMH, decreased LH pulse frequency. In summary, FSH secretion is controlled by synergistic interactions between inhibin and estradiol or testosterone, whereas GnRH/LH pulse frequency is controlled by testicular steroids. Estradiol acts partly, at least, in the ARC, but the central site of action, testosterone remains unknown.

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Nude rats bearing melanomas on their hindlimbs were treated by isolated limb infusion (ILI) with increasing doses (7.5-400 mug/ml) of melphalan. The response of tumours to treatment at the end of the observation period was graded, according to diameter, as complete response (CR), partial response (PR), no change (NC) or progressive disease (PD). No linear relationship between the dose of melphalan and the tumour response was observed. All doses above a threshold of 15 mug/ml achieved a PR or CR. The achievement of CR was not related to increased dose. Two major implications arise from this work. Firstly, the typically two-to three-fold increase in cytotoxic drug concentration given in high dose chemotherapy compared with standard drug concentration may not be sufficient to produce the expected increase in tumour response and possibly survival, and the controversial results of high dose chemotherapy in different studies may thus be explained. Secondly, since an increase in melphalan dose above a certain threshold does not greatly increase tumour response, the use of combination therapies would seem to be more likely to be effective than increased chemotherapeutic drug doses in achieving better tumour responses.

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We report our experience with the combination of anti-thymocyte globulin (ATGAM) and tacrolimus in the treatment of 20 patients with steroid refractory and dependent acute graft-versus-host disease (GVHD) transplanted between August 1996 and February 2000. All patients received cyclosporine-based GVHD prophylaxis. Thirteen patients developed a maximum of grade TV, five grade III and two grade II acute GVHD, with 15 patients being refractory to steroids and five dependent on steroids. Patients were treated with ATGAM (15 mg/kg for 5 d) and tacrolimus (0.025-0.1 mg/kg/d) in addition to continuation of their high-dose steroids and cessation of their cyclosporine. Within 28 d of treatment, we observed eight complete responses (CR), six partial responses (PR) and six with no response. Overall response (CR + PR) was predicted by GVHD severity. Infectious complications occurred in 80% of patients. The median survival was 86.5 d (range, 21-1081 d) with 35% of patients remaining alive, Survival following combination therapy was significantly more likely in men (P < 0.001), skin-only GVHD (P = 0.027), less severe GVHD (P = 0.048), and in responders to tacrolimus and ATGAM (P< 0.001). In conclusion, concurrent introduction of ATGAM and tacrolimus is a promising therapeutic combination for GVHD refractory to steroids and cyclosporine.

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Background: Tuberculosis is an important cause of wasting. The functional consequences of wasting and recovery may depend on the distribution of lost and gained nutrient stores between protein and fat masses. Objective: The goal was to study nutrient partitioning, ie, the proportion of weight change attributable to changes in fat mass (FM) versus protein mass (PM), during anti mycobacterial treatment. Design: Body-composition measures were made of 21 men and 9 women with pulmonary tuberculosis at baseline and after 1 and 6 mo of treatment. All subjects underwent dual-energy X-ray absorptiometry and deuterium bromide dilution tests, and a four-compartment model of FM, total body water (TBW), bone minerals (BM), and PM was derived. The ratio of PM to FM at any time was expressed as the energy content (p-ratio). Changes in the p-ratio were related to disease severity as measured by radiologic criteria. Results: Patients gained 10% in body weight (P < 0.001) from baseline to month 6. This was mainly due to a 44% gain in FM (P < 0.001); PM, BM, and TBW did not change significantly. Results were similar in men and women. The p-ratio decreased from baseline to month 1 and then fell further by month 6. Radiologic disease severity was not correlated with changes in the p-ratio. Conclusions: Microbiological cure of tuberculosis does not restore PM within 6 mo, despite a strong anabolic response. Change in the p-ratio is a suitable parameter for use in studying the effect of disease on body composition because it allows transformation of such effects into a normal distribution across a wide range of baseline proportion between fat and protein mass.

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Histone deacetylase inhibitors (HDACi) are a promising new class of chemotherapeutic drug currently in early phase clinical trials. A large number of structurally diverse HDACi have been purified or synthesised that mostly inhibit the activity of all eleven class I and II HDACs. While these agents demonstrate many features required for anti-cancer activity such as low toxicity against normal cells and an ability to inhibit tumor cell growth and survival at nanomolar concentrations, their mechanisms of action are largely unknown. Initially, a model was proposed whereby HDACi-mediated transactivation of a specific gene or set of genes was responsible for the inhibition of cell cycle progression or induction of apoptosis. Given that HDACs can regulate the activity of a number of nonhistone proteins and that histone acetylation is important for events such as DNA replication and mitosis that do not directly involve gene transcription, it appears that the initial mechanistic model for HDACi may have been too simple. Herein, we provide an update on the transcription-dependent and - independent events that may be important for the anti-tumor activities of HDACi and discuss the use of these compounds in combination with other chemotherapeutic drugs.

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The effects of free ammonia (FA; NH3) and free nitrous acid (FNA; HNO2) concentrations on the metabolisms of an enriched ammonia oxidizing bacteria (AOB) culture were investigated using a method allowing the decoupling of growth and energy generation processes. A lab-scale sequencing batch reactor (SBR) was operated for the enrichment of an AOB culture. Fluorescent in-situ hybridization (FISH) analysis showed that 82% of the bacterial population in the SBR bound to the NEU probe specifically designed for Nitrosomonas europaea. Batch tests were carried out to measure the oxygen and ammonium consumption rates by the culture at various FA and FNA levels, in the presence or absence of inorganic carbon (CO2, HCO3, and CO32-). It was revealed that FA of up to 16.0 mgNH(3)-N (.) L-1, which was the highest concentration used in this study, did not have any inhibitory effect on either the catabolic or anabolic processes of the Nitrosomonas culture. In contrast, FNA inhibited both the growth and energy production capabilities of the Nitrosomonas culture. The inhibition on growth initiated at approximately 0.10 mgHNO(2)-(NL-1)-L-., and the data suggested that the biosynthesis was completely stopped at an FNA concentration of 0.40 mgHNO(2)-N (.) L-1. The inhibition on energy generation initiated at a slightly lower level but the Nitrosomonas culture was still oxidizing ammonia at half of the maximum rate at an FNA concentration of 0.50-0.63 mgHNO(2)-N (.) L-1. The affinity constant of the Nitrosomonas culture with respect to ammonia was determined to be 0.36 mgNH3-N (.) L-1, independent of the presence or absence of inorganic carbon. (c) 2006 Wiley Periodicals, Inc.

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To evaluate the effects of adding exercise and maintenance to cognitive-behavior therapy (CBT) for binge eating disorder (BED) in obese women. One hundred fourteen obese female binge eaters were randomized into four groups: CBT with exercise and maintenance, CBT with exercise, CBT with maintenance, and CBT only. Eighty-four women completed the 16-month study. Subjects who received CBT with exercise experienced significant reductions in binge eating frequency compared with subjects who received CBT only. The CBT with exercise and maintenance group had a 58% abstinence rate at the end of the study period and an average reduction of 2.2 body mass index (BMI) units (approximately 14 lb). BMI was significantly reduced in the subjects in both the exercise and maintenance conditions. The results suggest that adding exercise to CBT, and extending the duration of treatment, enhances outcome and contributes to reductions in binge eating and BMI.

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This study investigated the ability of negatively versus positively perceived stress to predict outcome of treatment for binge eating disorder (BED). Participants were 62 obese women satisfying the DSMIV research criteria for BED. Stress was measured using an instrument based on the Recent Life Change Questionnaire (RLCQ). Participants experiencing high negative stress during the study period reported a binge eating frequency three times greater than that reported by subjects experiencing low negative stress (2.14 vs. 0.65 binge-days/week). Negative stress predicted how fast an individual would reduce binge eating and demonstrated more predictive power than positive stress.

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A Pilot-Scale Engineered Ecosystem (PSEE) operated for over two years in sub-tropical conditions, produced an effluent with COD (median 38 mg/L) and TSS (median 3 mg/L) levels comparable to that required by the AS/NZS 1547:2000 Onsite Domestic Wastewater Management standard. Only partial nitrification was achieved as dissimilatory nitrate reduction to ammonia occurred; however the level of NH4-N was reduced by 75% and total inorganic nitrogen by 53%. Phosphorus was not removed by the system due to the lack of regular sludge removal. Mass balances around the system showed that bacteria removed 36% of the influent nitrogen and 76% of the influent COD. Algae and plants were shown to remove 5% of the influent nitrogen, and 6% of the influent phosphorus. Challenges in developing a sustainable on-site wastewater treatment system were largely met by minimising chemical, energy and labour inputs, eliminating the need for frequent sludge handling, and creating an effluent quality suitable for re-use in non-potable applications. However, the sludge removal from the system needs to be adequately managed to avoid excessive accumulation as this can cause a range of negative impacts.

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A method is presented for the direct extraction of the recombinant protein Long-R-3-IGF-I from inclusion bodies located in the cytoplasm of intact Escherichia coli cells. Chemical treatment with 6M urea, 3 mM EDTA, and 20 mM dithiothreitol (DTT) at pH 9.0 proved an effective combination for extracting recombinant protein from intact cells. Comparable levels of Long-R-3-IGF-I were recovered by direct extraction as achieved by in vitro dissolution following mechanical disruption. However, the purity of directly extracted recombinant protein was lower due to contamination by bacterial cell components. The kinetics of direct extraction are described using a first-order equation with the time constant of 3 min. Urea appears important for permeabilization of the cell and dissolution of the inclusion body. Conversely, EDTA is involved in permeabilization of the cell wall and DTT enhances protein release. pH proved to be important with lower levels of protein release achieved at low pH values (