Effects of exercise training in water and on land in patients with COPD: a randomised clinical trial.

OBJECTIVES: To compare the effects of two similar 6-month protocols of high-intensity exercise training, in water and on land, in patients with chronic obstructive pulmonary disease (COPD). DESIGN: Randomised controlled trial. SETTING: University-based outpatient clinic. PARTICIPANTS: Thirty-six patients with predominantly moderate-to-severe COPD completed the study. INTERVENTION: Patients were evaluated at baseline, at 3 months and at the end of the programme (i.e. 6 months). For both groups, the 6-month protocol consisted of high-intensity endurance and strength exercises with gradual increase in time and/or workload, totalling 60 sessions. MAIN OUTCOMES: Objective monitoring of physical activity in daily life (PADL, primary outcome), lung function, peripheral and respiratory muscle strength, body composition, maximal and submaximal exercise capacity, functional status, quality of life, and symptoms of anxiety and depression. RESULTS: After 6 months of training, a significant improvement in PADL was seen for both groups [mean difference (95% confidence interval): land group 993 (358 to 1628) steps/day; water group 1669 (404 to 2934) steps/day]. Significant improvements were also seen in inspiratory, expiratory and peripheral muscle strength; maximal and submaximal exercise capacity; quality of life and functional status for both groups. There were no significant improvements in lung function, body composition, and symptoms of anxiety and depression for either group. No difference was found in the magnitude of improvement between the two types of training for any outcome. CONCLUSION: High-intensity exercise training in water generates similar effects compared with training on land in patients with moderate-to-severe COPD, rendering it an equally beneficial therapeutic option for this population. CLINICAL TRIAL REGISTRATION NUMBER: NCT01691131.

Soluble CD30, Acute Rejection, and Graft Survival: Pre- and 6-Month Post-Transplant Determinations-When Is the Best Time to Measure?

BACKGROUND: Pretransplantation soluble CD30 (sCD30) has been shown to be a good predictor of acute rejection (AR) and graft loss. This study aimed to evaluate the effectiveness of sCD30 measured pretransplant and up to 6 months after transplantation as a predictor of AR, graft loss, and survival at 5 years post-transplantation. Subjects were patients receiving living donor renal transplants at Bonsucesso Federal Hospital (Rio de Janeiro) in 2006 and between August 2010 and May 2011. METHODS: sCD30 was analyzed in samples collected pretransplantation and 7, 14, and 21, 28 days and 3, 4, 5, and 6 months post-transplantation from 73 kidney recipients. RESULTS: Patients in the AR group did not present a positive correlation with the sCD30 levels pretransplant (P = .54); in the post-transplant period, the 7- to 14-day samples showed patients with AR had higher levels of this biomarker (P = .036). The graft survival in 5 years of follow-up was not different between groups. CONCLUSIONS: The best time to predict AR using sCD30 is the 7- to 14-day sample; however, identifying and following the decrease of this biomarker from pre- to post-transplant seems to be better than just 1 measurement. The sCD30 post-transplant is another tool that may be used in monitoring patients after renal transplantation.

Freshwater shrimps (Macrobrachium depressimanum and Macrobrachium jelskii) as biomonitors of Hg availability in the Madeira River Basin, Western Amazon.

Total mercury (THg) concentrations measured in two freshwater shrimp species (Macrobrachium depressimanum and Macrobrachium jelskii) showed a relationship with the location of artisanal and small-scale gold mining (ASGM) from the Madeira River Basin, Western Amazon. Between August 2009 and May 2010, 212 shrimp samples were collected in the confluence of the Madeira River with three of its tributaries (Western Amazon). THg concentration was quantified in the exoskeleton, hepatopancreas and muscle tissue of the shrimps by cold vapor atomic absorption spectrophotometry. There were no significant differences between the two shrimp species when samples came from the Madeira River, but Hg concentrations were significantly lower in a tributary outside the influence of the gold mining area. Average THg concentrations were higher in the hepatopancreas (up to 160.0 ng g-1) and lower in the exoskeleton and muscle tissue (10.0-35.0 ng g-1 and < 0.9-42.0 ng g-1, respectively). Freshwater shrimps from the Madeira River respond to local environmental levels of Hg and can be considered as biomonitors for environmental Hg at this spatial scale. These organisms are important for moving Hg up food webs including those that harbor economic significant fish species and thus enhancing human exposure.

Therapeutic salivary monitoring of IV busulfan in patients undergoing hematopoietic stem cell transplantation: a pilot study.

Individual therapeutic monitoring of busulfan (BU) minimizes its toxicity and improves the therapeutic outcomes during hematopoietic stem cell transplantation (HSCT). For individual dose adjustment, several blood collections are performed that are uncomfortable for patients. The aim of this pilot study was to validate a laboratory method for quantification of BU in saliva and to present the results obtained using this protocol in HSCT patients. We performed analyses of selectivity, precision and accuracy of saliva with standard concentrations of BU using ultra-high-performance liquid chromatography with diode array detection. We also determined salivary and plasmatic concentrations of BU in six HSCT patients. Saliva exhibited excellent selectivity, precision and accuracy for quantification of BU. In the patient samples, significant correlations were noted between plasmatic and salivary concentrations of BU (r=0.97, P<0.001 in the test dose; r=0.93, P<0.001 in the adjusted dose). Passing &Bablok regression revealed good agreement between the two methods (R2=0.956 for test dose; R2=0.927 for adjusted dose). In conclusion, the saliva is safe for laboratory BU measurement. The good agreement with plasma encourages further clinical studies using saliva for BU therapeutic monitoring.

Spatial-temporal dynamics and sources of total Hg in a hydroelectric reservoir in the Western Amazon, Brazil.

Damming rivers to construct hydroelectric reservoirs results in a series of impacts on the biogeochemical Hg cycle. For example, modifying the hydrodynamics of a natural watercourse can result in the suspension and transport of Hg deposits in the water column, which represents an exposure risk for biota. The objective of this study was to evaluate the influences of seasonality on the dispersion of total Hg in the Hydroelectric Power Plant (HPP)-Samuel Reservoir (Porto Velho/Brazil). Sampling campaigns were performed during the three following hydrological periods characteristic of the region: low (Oct/2011), ebbing (May/2012), and high (Feb/2013) water. Sediment profiles, suspended particulate matter (SPM), and aquatic macrophytes (Eicchornia crassipes and Oryza spp.) were collected, and their Hg concentrations and isotopic and elemental C and N signatures were determined. The drainage basin significantly influenced the SPM compositions during all the periods, with a small autochthonous influence from the reservoir during the low water. The highest SPM Hg concentrations inside the reservoir were observed during the high water period, suggesting that the hydrodynamics of this environment favor the suspension of fine SPM, which has a higher Hg adsorption capacity. The Hg concentrations in the sediment profiles were ten times lower than those in the SPM, indicating that large particles with low Hg concentrations were deposited to form the bottom sediment. Hg concentrations were higher in aquatic macrophyte roots than in their leaves and appeared to contribute to the formation of SPM during the low water period. In this environment, Hg transport mainly occurs in SPM from the Jamari River drainage basin, which is the primary source of Hg in this environment.

Role of sex hormones in hypercapnia-induced activation of the locus coeruleus in female and male rats.

The locus coeruleus (LC) has been suggested as a CO2 chemoreceptor site in mammals. Most of the studies involving the role of the LC in hypercapnic ventilatory responses have been performed in males. Since ovarian steroids modulate the activity of LC neurons and females have a different respiratory response to CO2 than males, we evaluated the activity of LC noradrenergic neurons during normocapnia and hypercapnia in female and male rats with distinct sex hormone levels. Ovariectomized (OVX), estradiol (E2)-treated ovariectomized (OVX+E2) and female rats on the diestrous day of the estrous cycle were evaluated. Concurrently, males were investigated as gonad-intact, orchidectomized (ORX), testosterone (T)-treated ORX (ORX+T), and E2-treated ORX (ORX+E2). Activation of LC neurons was determined by double-label immunohistochemistry to c-Fos and tyrosine hydroxylase (TH). Hypercapnia induced by 7% CO2 increased the number of c-Fos/TH-immunoreactive (ir) neurons in the LC of all groups when compared to air exposure. Hypercapnia-induced c-Fos expression did not differ between diestrous females and intact male rats. In the OVX+E2 group, there was attenuation in the c-Fos expression during normocapnia compared with OVX rats, but CO2 responsiveness was not altered. Moreover, in ORX rats, neither T nor E2 treatments changed c-Fos expression in LC noradrenergic neurons. Thus, in female rats, E2 reduces activation of LC noradrenergic neurons, whereas in males, sex hormones do not influence the LC activity.

Planned randomized conversion from tacrolimus to sirolimus-based immunosuppressive regimen in de novo kidney transplant recipients.

Planned conversion from tacrolimus to sirolimus was evaluated in de novo kidney transplant recipients. In this multicenter, randomized, open-label study, 297 patients were initially treated with tacrolimus, mycophenolate sodium and prednisone. Of the 283 patients reaching 3 months, 97 were converted to sirolimus (SRL), 107 were maintained on tacrolimus (TAC) and 79 were patients receiving TAC without criteria to undergo intervention at month 3 (TACex). The primary objective was to show superior estimated glomerular filtration rate (eGFR) in the SRL group at month 24. Of the 258 patients who completed 24 months, 91 (94%) were in the SRL group, 101 (94%) in the TAC group and 66 (84%) in the TACex group. In the intention-to-treat population there were no differences in eGFR (66.2 ± 25.3 vs. 70.7 ± 25.1, p = 0.817) or in the severity of chronic sclerosing lesions scores in 24-month protocol biopsies. Higher mean urinary protein-to-creatinine ratio (0.36 ± 0.69 vs. 0.15 ± 0.53, p = 0.03) and higher incidence of treated acute rejection between months 3-24 (13.4% vs. 4.7%, p = 0.047) were observed in SRL compared to TAC group. In this population planned conversion from TAC to SRL 3 months after kidney transplantation was not associated with improved renal function at 24 months.

Molecular identification of the hybrid between the catfish species Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum using a set of eight microsatellite markers.

This study distinguished hybrids of surubim or pintado Pseudoplatystoma corruscans and cachara Pseudoplatystoma reticulatum from pure strains using a set of eight microsatellite markers and population assignment methods. Applications of this molecular tool range from certification of hybrid-free breeders in restocking conservation programmes to the identification of fish products lacking traditional morphological characteristics.

N-acetyl transferase 2 and cytochrome P450 2E1 genes and isoniazid-induced hepatotoxicity in Brazilian patients.

SETTING: Isoniazid (INH) is related to the development of hepatotoxicity in some patients. OBJECTIVE: To investigate the role of N-acetyl transferase 2 (NAT2) and cytochrome P450 2E1 (CYP2E1) in the hepatotoxicity of patients treated with INH in an Amazonian Brazilian population. DESIGN: Patients undergoing anti-tuberculosis treatment were investigated. Hepatotoxicity was defined as an increase of more than three times the upper limit of normal in serum alanine aminotransferase levels after treatment. NAT2 genotypes were identified by sequencing, whereas CYP2E1 alleles were detected using polymerase chain reaction based methods. RESULTS: Of the 270 individuals included in the study, 18 (6.7%) developed drug-related hepatotoxicity. A high association was found between slow acetylators and hepatotoxicity, particularly with regard to allele *5. The adjusted risk of developing hepatotoxicity was significant in individuals carrying two slow acetylation alleles (P = 0.036, OR 3.05, 95%CI 1.07-8.64). In all of the CYP2E1 markers examined, wild homozygous genotypes were more prevalent in subjects with hepatotoxicity than in controls; however, the difference was not statistically significant. Joint evaluation of the genes revealed a high risk of developing hepatotoxicity in slow acetylators with CYP2E1 wild alleles (adjusted OR 4.26; 95%CI 1.47-12.37, P = 0.008). CONCLUSIONS: Large-scale screening for NAT2 and CYP2E1 genotypes can prove useful in predicting the risk of adverse effects.

BCR-ABL-mediated upregulation of PRAME is responsible for knocking down TRAIL in CML patients.

Tumor necrosis factor-related apoptosis-inducing ligand-TNFSF10 (TRAIL), a member of the TNF-α family and a death receptor ligand, was shown to selectively kill tumor cells. Not surprisingly, TRAIL is downregulated in a variety of tumor cells, including BCR-ABL-positive leukemia. Although we know much about the molecular basis of TRAIL-mediated cell killing, the mechanism responsible for TRAIL inhibition in tumors remains elusive because (a) TRAIL can be regulated by retinoic acid (RA); (b) the tumor antigen preferentially expressed antigen of melanoma (PRAME) was shown to inhibit transcription of RA receptor target genes through the polycomb protein, enhancer of zeste homolog 2 (EZH2); and (c) we have found that TRAIL is inversely correlated with BCR-ABL in chronic myeloid leukemia (CML) patients. Thus, we decided to investigate the association of PRAME, EZH2 and TRAIL in BCR-ABL-positive leukemia. Here, we demonstrate that PRAME, but not EZH2, is upregulated in BCR-ABL cells and is associated with the progression of disease in CML patients. There is a positive correlation between PRAME and BCR-ABL and an inverse correlation between PRAME and TRAIL in these patients. Importantly, knocking down PRAME or EZH2 by RNA interference in a BCR-ABL-positive cell line restores TRAIL expression. Moreover, there is an enrichment of EZH2 binding on the promoter region of TRAIL in a CML cell line. This binding is lost after PRAME knockdown. Finally, knocking down PRAME or EZH2, and consequently induction of TRAIL expression, enhances Imatinib sensibility. Taken together, our data reveal a novel regulatory mechanism responsible for lowering TRAIL expression and provide the basis of alternative targets for combined therapeutic strategies for CML.

Comparison of the safety and efficacy of cyclosporine minimization versus cyclosporine elimination in de novo renal allograft patients receiving sirolimus.

The safety and efficacy of concentration-controlled use of sirolimus (SRL) and cyclosporine (CsA) followed by CsA minimization (CsAm) or elimination (CsAe) beginning at week 13 was compared in a phase 4, open-label, randomized (1:1) trial of renal transplant recipients enrolled between March 2004 and November 2005. The primary endpoint was renal function, measured at 12 months using the Nankivell formula, in patients remaining on therapy. Though a total enrollment of 140 patients in each group was planned to provide an 80% power to detect a difference in means, only 207 subjects were enrolled in this study. Demographic characteristics were similar between groups, with 98.1% recipients of first grafts, 69.1% from living donors, and 7.2% diabetics. At 12 months, there were no differences in renal function (61.08 vs 65.24 mL/min, P = .132); incidence of biopsy-confirmed acute rejection (14.3% vs 22.5%, P = .152); and patient (89.5% vs 92.2%, P = .632), graft (87.6% vs 88.2%, P = .999), and death-censored graft (98.1% vs 94.1%, P = .166) survivals between CsAm and CsAe groups, respectively. There were no differences in the overall rate of study-drug discontinuation (32.4% vs 36.3%, P = .562) but more patients discontinued because of lack of efficacy/graft loss in the CsAe group (4.8% vs 14.7%, P = .018). This study was underpowered to demonstrate the superiority of one regimen over the other. In summary, SRL immunotherapy combined with CsA minimization or elimination showed comparative safety and efficacy. Both regimens offer potential treatment options for de novo renal allograft recipients.

Toxicity of phospholipases A2 D49 (6-1 and 6-2) and K49 (Bj-VII) from Bothrops jararacussu venom.

Purified phospholipase A2 (PLA2) enzymes from Bothrops jararacussu snake venom were examined to evaluate NIH 3T3 and COS7 fibroblast cytotoxicity, as well as muscle myotoxic and inflammatory activities. Separation of fractions Bj-VII (from BthTX-I; a Lys49 PLA2 homolog) and 6-1 and 6-2 (from BthTX-II; an Asp49 PLA2) from B. jararacussu snake venom by SDS-PAGE in tricine buffer in the absence and presence of dithiothreitol revealed a homodimer with an estimated molecular mass of approximately 30 kDa (monomer mass approximately 15 kDa). This finding indicates that these toxins form dimeric complexes-a previously reported tendency among PLA2s. These toxins were assayed for viability with the MTT assay, which is used to examine the effects of phospholipases on the mitochondrial viability of cells. The toxins were also assayed for cytolysis of the fibroblast cell lines NIH 3T3 and COS7 by quantification of lactate dehydrogenase released into the medium. The results indicate that the PLA2s 6-1, 6-2 and the Bj-VII PLA2 homolog studied here induce moderate footpad edema and local myotoxicity. Moreover, exposure to these phospholipases led to a reduction in fibroblast viability; at the 1 muM dose of PLA2 tested, a reduction of 50% in cell viability was observed. The present findings indicate that the inflammatory activity observed in envenomation may be correlated with the cytotoxicity observed in fibroblasts.

[Evaluation of the drug interaction between carbamazepine and lamotrigine in the treatment of refractory epilepsy patients]. / Evaluación de la interacción medicamentosa de la carbamacepina y la lamotrigina en el tratamiento de los pacientes epilépticos refractarios.

INTRODUCTION: Carbamazepine (CBZ) is a pharmacological agent used to control epileptic syndromes. In refractory epilepsy patients, however, a second anticonvulsive drug such as lamotrigine (LTG) is often added. This association can reduce the frequency of the epileptic seizures and favour control over them. AIMS: This study was conducted to evaluate the plasma concentration of CBZ throughout a period of mono and polytherapy. Furthermore, tests were also carried out to determine whether any alterations were caused in the haematological parameters or in plasma concentrations by adding LTG to the therapy with CBZ. PATIENTS AND METHODS: This study involved a sample of refractory epilepsy patients who were following monotherapy with CBZ and who had a wholly unsatisfactory control over their bouts of seizures. LTG was thus added to these patients' treatment in an attempt to improve their control over the seizures. RESULTS AND CONCLUSIONS: On ending the study, we found that LTG did not interfere with the plasma concentrations of CBZ or give rise to any kind of alteration in the haematological parameters of any of the patients. Nevertheless, one patient did break out in a rash, which shows that therapeutic monitoring may be a key tool, especially when the treatment that is prescribed includes two drugs with a narrow therapeutic range.

Incidence of delayed graft function in cadaveric kidney transplants in Brazil: a multicenter analysis.

To evaluate the frequency of delayed graft function (DGF) in kidney transplant centers in Brazil, we sent a questionnaire requesting information on the number of cadaveric donor kidney transplants performed during the years 2000, 2001, and 2002, the number of early nonfunctioning grafts, and the number of patients on dialysis during the first posttransplant week with subsequent recovery. Among all centers performing more than 50 kidney transplants during the last year of evaluation, 6, performing 612 cadaveric kidney transplants during the study period, replied to the questionnaire. Sixty procedures (9.7%) resulted in nonfunctioning grafts, while 312 (55.6%) patients required dialysis during the first Ptx week: 216 (53.9%) in 2000, 189 (62.3%) in 2001, and 216 (51.6%) in 2002. The frequency of DGF during the study period was higher than that noted by several previous foreign studies. To better evaluate the possible causes of this finding, a more extensive and focused study is warranted.

Energy expenditure during rest and treadmill gait training in quadriplegic subjects.

STUDY DESIGN: The analysis of oxygen uptake (VO(2)) and energy consumption in quadriplegics after 6 months of treadmill gait with neuromuscular electrical stimulation (NMES). OBJECTIVES: To compare metabolic responses in quadriplegics after 6 months of treadmill training, with NMES (30-50% body weight relief), with quadriplegics who did not perform gait. SETTING: Ambulatory of University Hospital, Brazil. METHODS: Quadriplegics were separated into gait and control groups (CGs). On inclusion, all subjects performed VO(2) test. In the gait group (GG) (n=11), the protocol consisted of 8 min of rest, 10 min of treadmill walking using NMES and 10 min of recovery. In the CG (n=10), testing consisted of 8 min rest, 15 min of quadriceps endurance exercise in sitting position with NMES and 10 min recovery. VO(2), carbon dioxide production (VCO(2)) and energy consumption were measured. The GG performed 6 months of treadmill training, using NMES, for 20 min, twice a week. The CG did not practice any activity with NMES, performing conventional physiotherapy only; the CG was stimulated only during the cardiorespiratory test. RESULTS: All parameters increased significantly for the GG: 36% for VO(2) (l/min), 43% for VCO(2) (l/min) and 32.5% for energy consumption (J/kg/s). For the CG, during knee extension exercise, VO(2) increased without changes in the energy consumption (P<0.05); smaller values were obtained for all parameters when compared to those obtained during gait. CONCLUSIONS: Quadriplegic gait was efficient towards increasing VO(2) and energy consumption, which can decrease the risk of cardiovascular diseases.

Tuberculosis in renal transplants in Rio de Janeiro.

Retrospective analysis of 982 renal transplants over 21 years (1981 to 2002) sought to evaluate the prevalence of tuberculosis (TB). This analysis included 74 patients: 30 with a past TB history, who had INH prophylaxis since the beginning of immunosuppression, and 44 who only became TB infected after receiving transplants. The diagnosis of TB was made by a compatible medical situation with bacteriological/histological confirmation, which when not possible, underwent a therapeutic test occur. The average time for the illness to surge was 3 years. The mortality rate was 34.9% (15/44). Patients with hepatitis C were more affected. Among those who used INH prophylaxis only one contracted TB, showing that the drug displayed a protection rate of 96.6% (29/30).

Effect of BJcuL (a lectin from the venom of the snake Bothrops jararacussu) on adhesion and growth of tumor and endothelial cells.

Lectins are polyvalent carbohydrate-binding proteins of non-immune origin. Recently, we have isolated and characterized a lectin from the venom of the snake Bothrops jararacussu. This lectin (BJcuL) has been shown to bind to lactose moieties and induce agglutination of erythrocytes. In the present work, we observed that cells from human metastatic breast cancer (MDA-MB-435) and human ovarian carcinoma (OVCAR-5) cell lines adhere, although weakly, to BJcuL. However, BJcuL did not inhibit adhesion of these cells to the extracellular matrix proteins fibronectin, laminin and type I collagen. Importantly, viability of these tumor cells and cells from other human tumor cell lines and a bovine brain endothelial cell line was suppressed by BJcuL. These findings suggest that the lectin BJcuL may serve as an interesting tool for combating tumor progression by inhibiting tumor cell and endothelial cell growth.

[The various meanings of Brazil's certification as free of Chagas disease]. / Os diferentes significados da certificação conferida ao Brasil como estando livre da doença de Chagas.

The article discusses Brazil's recent certification as free of Chagas disease transmission by Triatoma infestans, analyzing the various meanings ascribed to this position. Resulting mainly from measures by both the Chagas Disease Control Program (PCDCh) established in Brazil in 1975 and the Southern Cone Initiative launched in 1991, this certification has been interpreted in ways that lead to confusion between the elimination of Chagas disease transmission by T. infestans and eradication of the disease. The present status of vector transmission control in Brazil is discussed, with emphasis on the Northeast, in most States of which T. infestans is not the main species involved in transmission. The article highlights the need to broaden the discussion of the readings and consequences involved in the present control achievements in light of possible harm from misinterpretations that might jeopardize further efforts to control the disease.

Characterization and distribution of extracellular matrix components and receptors in GH3B6 prolactin cells.

GH3B6 cells, a rat pituitary tumor cell line, synthesize and secrete large amounts of prolactin (PRL) in vitro. In the present work, we evaluated the capacity of these cells to express extracellular matrix (ECM) components and receptors in vitro. The expression of laminin (LN), fibronectin (FN) and type IV collagen (CIV) was investigated by immunofluorescence assays. In comparison to PRL distribution, where around 50-70% of the cells contained PRL concentrated in the Golgi region, a variable immunolabeling for the three ECM components could be observed in the majority of GH3B6 cells. Importantly, this pattern was not modified when cells were cultured in the presence of 30 nM thyroliberin (TRH). The expression of the ECM receptors: alpha5beta1 (FN receptor), alpha6beta1 (LN receptor) and CD44 (hyaluronic acid receptor) could be demonstrated by cytofluorometric analysis. Using biochemical procedures, we analyzed the synthesis and secretion of glycosaminoglycans (GAGs). The cells synthesized and secreted mainly heparan sulfate (75%) with a minor amount of chondroitin sulfate/dermatan sulfate. In an attempt to evaluate the individual contribution of the ECM components to influence cell morphology and PRL distribution in vitro, GH3B6 cells were cultivated separately on LN, FN and CIV substrates. Under all conditions, it was possible to observe an increase of cell adherence to the substrate, accompanied with changes of cellular morphology, characterized by the appearance of cytoplasmatic processes. However, no changes on PRL distribution could be observed. Our results suggest that endocrine tumor cell lines are involved in synthesis of ECM components and receptors.

A dual role of 20-hydroxyecdysone in the control of protein synthesis related to DNA puff activity in the anterior region of Bradysia hygida (Diptera, Sciaridae) salivary gland.

During the last 30 h of the larval stage, the salivary glands of Bradysia hygida show the amplification of some genes, resulting in the formation of two successive groups of DNA puffs, which direct the synthesis of two different sets of polypeptides. Incubation of anterior (S1) salivary gland regions, at age E7, beginning of first group of DNA puffs activity, in culture medium for 2 to 10 h results in a decrease in the synthesis of the polypeptides characteristic of this period. However, during subsequent incubation (from E7 to E7+12 h-24 h), when the second group of DNA puffs is active, S1 regions were able to synthesize some polypeptides characteristic of this period. The role of 20-OH ecdysone was studied, in vitro and in vivo, during these two periods of protein synthesis in S1 regions. The presence of the hormone was shown to be necessary to maintain, in vitro, the synthesis of the first set of polypeptides and was strongly inhibitory, in vitro and in vivo, to the synthesis of the second set of polypeptides. Thus, it is likely that the activity of the two distinct groups of DNA puffs is under opposite 20-OH-ecdysone control mechanisms.