Protein profile of Brazilian Pythium insidiosum isolates.

Pythium insidiosum is an important aquatic Oomycota that causes pythiosis in mammals, especially horses, dogs, and humans; these inhabit marshy environments in tropical and subtropical areas. The aim of this study was to determine the protein profile, as well as identify likely immunodominant proteins, of Brazilian P. insidiosum isolates from southern Brazil, an important equine pythiosis endemic area. P. insidiosum isolates (horses, n = 20 and dogs, n = 02) were analyzed by SDS-PAGE and Western blot techniques. Horse, cattle, dog, and rabbit sera of both diseased and healthy animals were used to identify P. insidiosum proteins. SDS-PAGE protein profile detected antigens of molecular weights ranging from 100 to 20 KDa. Dog isolates revealed a protein profile similar to that of horse isolates. Anti-P. insidiosum antibodies in the sera of the four species could recognize proteins of different molecular weights (∼74 KDa to ∼24 KDa), and proteins ∼50-55 KDa and ∼34 KDa were shown to be immunodominant. Furthermore, ∼74 KDa, ∼60 KDa, ∼30 KDa and ∼24 KDa proteins were poorly recognized by host species antibodies. The Brazilian P. insidiosum isolates analyzed showed a similar protein profile; however, further studies are essential for the identification and characterization of proteins expressed by P. insidiosum, and an evaluation of the immunological profile of hosts susceptible to this Oomycota is necessary.

Rosuvastatin promotes benefits on induced periodontitis in hypertensive rats.

BACKGROUND AND OBJECTIVE: The potential benefits of statins in modulating periodontal disease is supported by in vitro and clinical studies showing statins can induce a lower expression of proinflammatory cytokines and matrix metalloproteinases. The aim of this study was to evaluate the effects of rosuvastatin (ST) on ligature-induced periodontitis in spontaneously hypertensive rats (SHR). MATERIAL AND METHODS: Fifty-four adult male rats were divided into three groups: SHR-C, SHR-L and SHR-L-ST (C, control; L, ligature groups). In the SHR-L-ST group, animals were treated with daily 2 mg/kg ST administration. In L groups, a ligature remained around mandibular first molars for 10 d. Each group was divided for killing at 10 or 21 d postoperatively. Microtomographic and histometric analyses were performed. Osteoclastogenesis was evaluated by tartrate-resistant acid phosphatase assay and gene expression of 84 proinflammatory mediators by polymerase chain reaction array. RESULTS: The SHR-L-ST group showed reduced bone loss and attachment loss in comparison with the SHR-L group at both 10 and 21 d postoperatively (p < 0.05). ST decreased the amount of tartrate-resistant acid phosphatase-positive cells compared with the SHR-L group at both 10 and 21 d (p < 0.05). The SHR-L-ST group presented 14 genes differentially expressed when compared with SHR-L group, featuring a downregulated gene profile at 10 d. CONCLUSION: Statin therapy may promote a protective effect against alveolar bone and connective tissue attachment losses attributable to periodontitis in hypertensive rats through inflammatory gene profile modulation.

Natural Outbreak of BVDV-1d-Induced Mucosal Disease Lacking Intestinal Lesions.

Bovine viral diarrhea virus (BVDV) belongs to the Pestivirus genus, which is further divided into subgenotypes (1a-1u and 2a-c). When persistent infection occurs, the calf will be immunotolerant to BVDV and possibly develop mucosal disease. This study describes an outbreak of BVDV-1d-induced mucosal disease lacking intestinal lesions. Eleven calves presented with anorexia, sialorrhea, lameness, recumbency, and death. Three calves were necropsied, showing ulceration of the interdigital skin and the oral and nasal mucosa; linear ulcers in the tongue, esophagus, and rumen; and rounded ulcers in the abomasum. Microscopically, mucosa and skin had superficial necrosis, with single-cell necrosis and vacuolation in epithelial cells, and severe parakeratosis. Immunohistochemistry (IHC) showed BVDV antigen in the cytoplasm of epithelial cells in skin and mucosa. All 11 dead calves were positive upon reverse transcription-polymerase chain reaction (RT-PCR) for the detection of Pestivirus along with another 11 live calves from the herd, which were positive again by RT-PCR and IHC after a 4-week interval. Sequencing of the 5' untranslated region and N-terminal protease showed that viruses from these 22 calves were homologous and of subgenotype BVDV-1d. Cytopathic BVDV was isolated from 8 of 11 dead calves, but only noncytopathic BVDV was isolated from the 11 live animals. The findings indicate that this was an outbreak of mucosal disease caused by BVDV-1d, with high morbidity, and lesions restricted to the upper alimentary system and skin and absent from intestine. Thus, the epidemiological and pathological features in this form of mucosal disease may be similar to vesicular diseases, including foot and mouth disease.

Association of CYP1A1 (cytochrome P450) MspI polymorphism in women with endometriosis.

Endometriosis is a disease that affects 10 to 15% of the women of reproductive age. It is characterized by the presence of endometrial-like tissues outside of the uterus. Some definitions claim that the functional ectopic tissue is sensitive to the action of hormones. Severity of endometriosis is defined according to a system proposed by the American Society for Reproductive Medicine, which is based on laparoscopic findings. A large number of genetic polymorphisms has been reported for CYP1A1, the gene that is responsible for enzymes involved in stage I detoxification of xenobiotics; this gene is located at 15q22-24, and encodes an isoenzyme that catalyzes the oxidation of polycyclic aromatic hydrocarbons present in phenolic compounds and epoxides. The aim of this study was to analyze the frequency of the MspI polymorphism and its relation to endometriosis. We obtained peripheral blood samples from 52 women with endometriosis (confirmed by laparoscopy) as well as 42 women without endometriosis (control group). In the case group, the women were between 25 and 35 years of age; the age range was between 25 and 57 years old in the control group. Molecular analysis was performed by polymerase chain reaction. We found a significant association (P = 0.039) between the polymorphic allele m1 and endometriosis (32.70%). In conclusion, this study showed that the m1 polymorphism is associated with endometriosis, and that W1/m1 and m1/m1 polymorphisms are more frequently observed in patients with infertility and severe endometriosis.

Kinetic study of biodegradation of BTX compounds in mono- and multicomponent systems in reactor with immobilized biomass.

In this study, kinetic parameters were determined for the biodegradation of BTX compounds in a fixed-bed reactor with immobilized biomass, fed with mono- and multicomponent systems. The parameter estimation was achieved through an algorithm using the finite volume method. Different kinetic models were evaluated. The Monod model proved to be suitable to predict the experimental data for the biodegradation individual BTX compound. In multicomponent systems, it was found that the presence of more than one compound tends to cause competitive inhibition. To identify the models that best fit the experimental data, a statistical analysis using the F test was applied. For the two- and three-component systems the presence of more than one compound tends to cause competitive inhibition. In this study, it was possible to predict kinetic parameters in mono- and multicomponent systems as well as different operation conditions for a fixed-bed reactor with immobilized biomass.

Recurrent high-grade cervical lesion after primary conization is associated with persistent human papillomavirus infection in Norway.

OBJECTIVE: This retrospective registry-based study aimed to assess the human papillomavirus (HPV)-type distribution in primary and recurrent high-grade cervical intraepithelial neoplasia (CIN2+), and to discriminate pre-existing from newly-acquired infections. METHODS: Cervical specimens from 58 women (median age (Q1-Q3): 37.6 (31.7-44.9)) who underwent primary (1998-2003) and repeat conizations were confirmed as CIN2+ during expert pathology review. HPV testing was performed using PCR MP-TS123 Luminex for 16 HPV types. Molecular HPV16 E6 and HPV18 LCR DNA sequencing was performed on specimens with persistent HPV16/18. RESULTS: All 58 paired cones were HPV positive; 49 had CIN3+ in the primary cone. Forty-seven (95.9%) women with primary CIN3+ and recurrent CIN2+ had persistent high-risk (hr) HPV infection, of which 74.5% were HPV16/18. Two women had probable newly-acquired HPV16/52/56 and HPV39 infections. One woman with persistent HPV52 also had a probable new HPV16 E6 variant in the recurrent CIN2+. Median time delay (Q1-Q3) between conizations was 2.0 years (1.1-4.0), being shorter for women older than 40 years: 2.6 years (1.1-3.7) than for women younger than 40 years: 6.0 years (2.0-8.7). Primary conization histology revealed CIN3, cervical adenocarcinoma in situ and microinvasive carcinomas in 43 (87.8%), 5 (10.2%) and 1 (2.0%) women, respectively. Primary HPV16- and HPV18-infected CIN3+ had a shorter delay between conizations: 1.8years (1.2-4.4) and 2.2 years (0.4-NE), respectively, compared to HPV33-: 3.8 years (3.3-7.8) or other HPV type-infected: 8.2 years (6.0-NE) CIN3+. CONCLUSIONS: Routine post-conization hr-HPV DNA testing together with cervical cytology may provide a better prediction for potential recurrent disease. Further, primary prevention through adolescent vaccination may prevent CIN2+ and its recurrence.

Efficacy of disinfection procedures to reduce Acinetobacter baumanii blaOXA-23 contamination rate of needleless connectors: an in-vitro study.

Aim: This study aimed to verify the efficacy of disinfection procedures to reduce Acinetobacter baumannii blaOXA-23 bacterial load in needleless connectors that had been experimentally contaminated. Methods: Two-way intermediate extender's hub and needle-free valve were contaminated with Acinetobacter baumannii blaOXA-23. To disinfect them, the following procedures were carried out: sterile gauze with 70% ethanol, sterile gauze with Incidin®, and 70% isopropyl alcohol single-use cap, with eight times friction for 10 s, followed by 5 s drying time. The statistical tests Kruskal-Wallis and post-hoc Conover were performed using MedCalc®. Results: A total of 82 experiments were conducted. All tested disinfection procedures were efficacious in reducing the A. baumannii blaOXA-23 load. The 70% IPA single-use cap was found to be the best method for disinfecting the two-way intermediate extender's hub (87.28%), while all the methods were efficacious for the disinfection of the needle-free valve (more than 90%). During the inoculation period, A. baumannii blaOXA-23 showed less adherence to the needle-free valve during the inoculation period, probably due to the device's design. Conclusion: The three tested disinfection procedures using sterile gauze with 70% ethanol, sterile gauze with Incidin®, and 70% IPA single-use cap were found to be efficacious in reducing the bacterial load of A. baumanni blaOXA-23 in needleless connectors. Proper disinfection of needleless connectors is a crucial nursing practice to prevent bloodstream infections, as it significantly reduces the bacterial load present in the device.

A pilot study evaluating 99mTc-anti-TNF-alpha scintigraphy in graves' ophtalmopathy patients with different clinical activity score.

The present study describes the preliminary results of the use of 99mTc-anti-TNF-α scintigraphy as a new diagnostic approach to evaluate patients presenting with Graves' ophthalmopathy (GO). Patients (n=25) presenting at different inflammatory stages of GO and 10 healthy volunteers underwent 99mTc-anti-TNF-α scintigraphy. Images were obtained 15 min after the intravenous injection of 370 MBq (10 mCi) 99mTc-anti-TNF-α. Planar images were obtained in a 256×256 matrix (each lasting 5 min) and single photon emission computed tomography (SPECT) scan lasting 13 min. Regions of interest (ROI) were drawn on the orbit and cerebral hemispheres. The uptake of 99m Tc-anti-TNF-α in these regions was compared and positive scintigraphy established when the ROI was >2.5. In addition, uptake for each positive exam was scored as either slight (2.6-5.1), moderate (5.2-7.6), or high (>7.6). In this pilot study, 69 orbits were evaluated (1 patient had only 1 eye), and 27 had a positive CAS (≥3/7). Scintigraphies were positive in 38 orbits. Comparing the results of the exams with CAS, a high sensitivity and negative predictive values were determined for scintigraphy (96.3% and 96.7%, respectively). However, the specificity and the positive predictive values were 71.4% and 68.4%, respectively, with an accuracy of 81.2%. The exclusion of examinations that were slightly positive from the analysis resulted in an improvement in test accuracy (95.5%). The preliminary results suggest that 99mTc-anti-TNF-α scintigraphy is a promising procedure for the evaluation of active orbital inflammation in GO.

Measuring changes after multidisciplinary rehabilitation of obese individuals.

BACKGROUND: In 2009, the Italian Society of Obesity developed the short-form questionnaire for Obesity-related Disabilities (TSD-OC). AIMS: To stage the degree of disability in obese patients using TSD-OC; to verify its sensitivity to change after rehabilitation. SUBJECTS: Three hundred and fifty-five adult obese individuals [body mass index (BMI) >30 kg/m2] undergoing rehabilitation. Exclusion criteria were severe cardiovascular or respiratory diseases, neurological and psychological conditions. Sensitivity to change of TSD-OC was evaluated in 194 patients out of the initial sample. METHODS: To define the disability levels according to TSD-OC, the method of interquartile range was applied to the initial sample. The 194 in-patients were assessed with Roland-Morris Disability Questionnaire, Functional Independence Measure (FIM), Functional Visual Analogue Scale, and TSD-OC before (S0) and after 4 weeks (S1) of intensive (3 h daily) rehabilitation multidisciplinary program. Individuals were grouped according to age (1: age 30-59 yr; 2: age over 60 yr) and degree of obesity (BMI: A, 30-40 kg/m2; B, 40-50 kg/m2). RESULTS: At S1, BMI and all the clinical scores improved significantly in the whole study sample. The younger individuals with higher level of obesity showed a higher functional improvement (-51.3%). In the older subjects, improvement was not statistically different when varying BMI (A2 -13.7% vs B2 -14.6%). In the whole group, the TSD-OC improvement was statistically greater than the physical FIM gain (-25.9% vs +5.4%, p<0.05). CONCLUSIONS: Our data evidenced that the TSD-OC is a sensitive measure of short-term changes in disability status of obese individuals after rehabilitation.

"Extended Fitness" hypothesis: a link between individual and group selection.

What are the targets of natural selection remains a controversial issue in Biology. Here I propose the "Extended Fitness" hypothesis, in which extended phenotypes emerge as a link between individual and group selection. The basic premise of the extended fitness hypothesis is that extended phenotypes can be used by members of the same group since they are adapted to use them. Thus, extended phenotypes can also contribute to the fitness of members of the same species. Group selection emerges as a natural consequence of the shared use of extended phenotypes, which allow the evolutionary forces acting on individuals to become effective at the group level. The extended fitness hypothesis is supported by several observations found in nature. The hypothesis presented here provides a theoretical framework for the design of both modeling and experimental approaches to studying the role of extended phenotypes in group selection.

Construction and validation of metagenomic DNA libraries from landfarm soil microorganisms.

Landfarming biodegradation is a strategy used by the petrochemical industry to reduce pollutants in petroleum-contaminated soil. We constructed 2 metagenomic libraries from landfarming soil in order to determine the pathway used for mineralization of benzene and to examine protein expression of the bacteria in these soils. The DNA of landfarm soil, collected from Ilhéus, BA, Brazil, was extracted and a metagenomic library was constructed with the Copy Control(TM) Fosmid Library Production Kit, which clones 25-45-kb DNA fragments. The clones were selected for their ability to express enzymes capable of cleaving aromatic compounds. These clones were grown in Luria-Bertani broth plus L-arabinose, benzene, and chloramphenicol as induction substances; they were tested for activity in the catechol cleavage pathway, an intermediate step in benzene degradation. Nine clones were positive for ortho-cleavage and one was positive for meta-cleavage. Protein band patterns determined by SDS-polyacrylamide gel electrophoresis differed in bacteria grown on induced versus non-induced media (Luria-Bertani broth). We concluded that the DNA of landfarm soil is an important source of genes involved in mineralization of xenobiotic compounds, which are common in gasoline and oil spills. Metagenomic library allows identification of non-culturable microorganisms that have potential in the bioremediation of contaminated sites.

Residual entropy and magnetocaloric effect in a diluted sawtooth spin model of hole-doped CuO chains.

Ground-state and magnetocaloric properties of a site-diluted sawtooth magnetic chain in the presence of an external magnetic field are exactly investigated by using the transfer-matrix method. The model captures the main magnetic interactions along CuO chains present in some hole-doped cuprates. The ground-state diagram is exhibited and analytical expressions for the residual entropy within each ground state and along the transition lines are derived. We explicitly discuss the role of the underlying pairing correlations and the entropy maximization principle. The isothermal entropy change is determined as a function of interaction parameters, doping concentration, and magnetic-field amplitude. Normal and inverse magnetocaloric effects are reported. Adiabatic demagnetization curves are discussed in connection with configurational and spin contributions to the residual entropy.

Bioinformatics construction of the human cell surfaceome.

Cell surface proteins are excellent targets for diagnostic and therapeutic interventions. By using bioinformatics tools, we generated a catalog of 3,702 transmembrane proteins located at the surface of human cells (human cell surfaceome). We explored the genetic diversity of the human cell surfaceome at different levels, including the distribution of polymorphisms, conservation among eukaryotic species, and patterns of gene expression. By integrating expression information from a variety of sources, we were able to identify surfaceome genes with a restricted expression in normal tissues and/or differential expression in tumors, important characteristics for putative tumor targets. A high-throughput and efficient quantitative real-time PCR approach was used to validate 593 surfaceome genes selected on the basis of their expression pattern in normal and tumor samples. A number of candidates were identified as potential diagnostic and therapeutic targets for colorectal tumors and glioblastoma. Several candidate genes were also identified as coding for cell surface cancer/testis antigens. The human cell surfaceome will serve as a reference for further studies aimed at characterizing tumor targets at the surface of human cells.

Perinatal nutrient restriction induces long-lasting alterations in the circadian expression pattern of genes regulating food intake and energy metabolism.

OBJECTIVE: Several lines of evidence indicate that nutrient restriction during perinatal development sensitizes the offspring to the development of obesity, insulin resistance and cardiovascular disease in adulthood via the programming of hyperphagia and reduced energy expenditure. Given the link between the circadian clock and energy metabolism, and the resetting action of food on the circadian clock, in this study, we have investigated whether perinatal undernutrition affects the circadian expression rhythms of genes regulating food intake in the hypothalamus and energy metabolism in the liver. DESIGN: Pregnant Sprague-Dawley rats were fed ad libitum either a control (20% protein) or a low-protein (8% protein) diet throughout pregnancy and lactation. At weaning, pups received a standard diet and at 17 and 35 days of age, their daily patterns of gene expression were analyzed by real-time quantitative PCR experiments. RESULTS: 17-day-old pups exposed to perinatal undernutrition exhibited significant alterations in the circadian expression profile of the transcripts encoding diverse genes regulating food intake, the metabolic enzymes fatty acid synthase and glucokinase as well as the clock genes BMAL1 and Period1. These effects persisted after weaning, were associated with hyperphagia and mirrored the results of the behavioral analysis of feeding. Thus, perinatally undernourished rats exhibited an increased hypothalamic expression of the orexigenic peptides agouti-related protein and neuropeptide Y. Conversely, the mRNA levels of the anorexigenic peptides pro-opiomelanocortin and cocaine and amphetamine-related transcripts were decreased. CONCLUSION: These observations indicate that the circadian clock undergoes nutritional programming. The programming of the circadian clock may contribute to the alterations in feeding and energy metabolism associated with malnutrition in early life, which might promote the development of metabolic disorders in adulthood.

9°Yttrium-hydroxyapatite: a new therapeutic option for radioactive synovectomy in haemophilic synovitis.

Recurrent haemarthroses often lead to chronic synovitis in patients with haemophilia and von Willebrand disease. Radioactive synovectomy with yttrium-90 (9°Y) citrate is frequently used to treat this complication, usually with good results. Since 2006, the Nuclear Energy Research Institute (IPEN, Sao Paulo, Brazil) has produced hydroxyapatite particles labelled with 9°Y for radioactive synovectomy. The aim of this study was to compare the results achieved by both forms of 9°Y in the treatment of haemophilic synovitis. We included 221 joints from 136 patients (age range: 6-20 years), treated by one of the two radiopharmaceuticals, at the Hemocenter of Mato Grosso, Brazil. The outcomes analysed were the annual frequency of haemarthrosis, articular pain and joint range of motion before and 1 year after RS. Similar results were achieved regardless of whether 9°Y hydroxyapatite or 9°Y citrate was used, and results were independent of the joint type, age, gender, radiologic stage and presence of inhibitors. 9°Y hydroxyapatite appears to be equivalent to the reference product 9°Y citrate in the treatment of chronic synovitis associated with bleeding disorders.

Complementary hydropathy identifies a cellular prion protein receptor.

Prions, the etiological agents for infectious degenerative encephalopathies, act by entering the cell and inducing conformational changes in PrPC (a normal cell membrane sialoglycoprotein), which result in cell death. A specific cell-surface receptor to mediate PrPC and prion endocytosis has been predicted. Complementary hydropathy let us generate a hypothetical peptide mimicking the receptor binding site. Antibodies raised against this peptide stain the surface of mouse neurons and recognize a 66-kDa membrane protein that binds PrPC both in vitro and in vivo. Furthermore, both the complementary prion peptide and antiserum against it inhibit the toxicity of a prion-derived peptide toward neuronal cells in culture. Such reagents might therefore have therapeutic applications.

Low-temperature pseudo-phase-transition in an extended Hubbard diamond chain.

We consider the extended Hubbard diamond chain with an arbitrary number of particles driven by chemical potential. The interaction between dimer diamond chain and nodal couplings is considered in the atomic limit (no hopping), whereas the dimer interaction includes the hopping term. We demonstrate that this model exhibits a pseudo-transition effect in the low-temperature regime. Here, we explore the pseudo-transition rigorously by analyzing several physical quantities. The internal energy and entropy depict sudden, although continuous, jumps which closely resembles discontinuous or first-order phase-transition. At the same time, the correlation length and specific heat exhibit astonishing strong sharp peaks quite similar to a second-order phase-transition. We associate the ascending and descending parts of the peak with power-law "pseudo-critical" exponents. We determine the pseudo-critical exponents in the temperature range where these peaks are developed, namely, ν=1 for the correlation length and α=3 for the specific heat. We also study the behavior of the electron density and isothermal compressibility around the pseudo-critical temperature.

Peculiarities in pseudo-transitions of a mixed spin-(1/2, 1) Ising-Heisenberg double-tetrahedral chain in an external magnetic field.

Recently, it has been rigorously verified that several one-dimensional (1D) spin models may exhibit a peculiar pseudo-transition accompanied with anomalous response of thermodynamic quantities in a close vicinity of pseudo-critical temperature. In the present work we will introduce and exactly solve a mixed spin-(1/2,1) Ising-Heisenberg double-tetrahedral chain in an external magnetic field as another particular example of 1D lattice-statistical model with short-range interactions that displays a pseudo-transition of this type. The investigated model exhibits at zero temperature three ferrimagnetic phases, three frustrated phases, and one saturated paramagnetic phase. The ground-state phase diagram involves five unusual interfaces (phase boundaries), at which the residual entropy per site equals to a larger entropy of one of two coexisting phases. Four such interfaces are between a non-degenerate ferrimagnetic phase and a macroscopically degenerate frustrated phase, while one interface is between two non-degenerate ferrimagnetic phases. Though thermal excitations typically destroy all fingerprints of zero-temperature phase transitions of 1D lattice-statistical models with short-range forces, the mixed spin-(1/2,1) Ising-Heisenberg double-tetrahedral chain is quite robust with respect to thermal excitations and it displays peculiar pseudo-transitions close to all five aforementioned interfaces.

Anatomical description of the aortic arch of a rare species "the giant armadillo" (Priodontes maximus; Kerr, 1792).

The giant armadillo (Priodontes maximus) is found in diverse habitats from South America. A female adult giant armadillo with a body mass of 45 kg was used. The animal was a victim of trampling on highway AC-40, at 70 km, near the municipality of Capixaba-Acre and the corpse donated to the Animal Anatomy Laboratory at Federal University of Acre (UFAC). The arterial system was filled with natural latex via the thoracic aorta in a direction opposite the blood flow to facilitate the description of the aortic arch and its side branches. The study was approved by CEUA/UFAC - no. 053/2015 and SISBIO no. 47124-1. The aortic arch issued side groups, which had the following sequence: brachycephalic trunk, left carotid artery, left subclavian artery. The brachycephalic trunk forked forming the right subclavian artery and the right common carotid artery. The arrangement allowed the whole carotid blood supply to the brain and surrounding structures present in the animal's head. The subclavian arteries, of homologous way, originated the arteries: vertebral, thoracic, and cervical costocervical trunk. The aortic arch armadillo showed the same pattern as that described for the Euphractus sexcinctus and different from those reported for the Dasypus novemcinctus and Tamandua tetradactyla. In addition, the function assigned to each branch was the same regardless of the species with which it was compared.

Susceptibility to chemical insecticides of two Brazilian populations of the visceral leishmaniasis vector Lutzomyia longipalpis (Diptera: Psychodidae).

OBJECTIVES: To investigate the insecticide susceptibility of two geographically separated Lutzomyia longipalpis populations (Lapinha and Montes Claros) with different histories of insecticide exposure (i.e. no exposure and repeated exposure, respectively). METHODS: (i) Bioassay monitoring of sand fly survival over time when exposed to a range of insecticides; and (ii) analysis of the level of insecticide detoxification enzymes in individual sand flies caught at both study sites. Insecticides tested were the organophosphates malathion and fenitrothion and the pyrethroids lambda-cyhalothrin, permethrin and deltamethrin. RESULTS: Survival analyses showed that whilst there was no overall significant difference in susceptibility of both populations to organophosphates, Lapinha sand flies were significantly more susceptible to pyrethroids than those from Montes Claros. Multiple regression analyses also showed that insecticide susceptibility in both locations varied with sand fly sex. The relative susceptibilities of the two sand fly populations to tested insecticides were also compared. Thus, Montes Claros sand flies were most susceptible to malathion, followed by fenitrothion, deltamethrin and permethrin. Those from Lapinha were most susceptible to lambda-cyhalothrin, followed by malathion, permethrin, deltamethrin and fenitrothion. Biochemical analyses demonstrated that Montes Claros sand flies had significantly lower insecticide detoxification enzyme activity than Lapinha sand flies. CONCLUSIONS: Our results are the first record of significantly reduced susceptibility to the insecticides used in control of wild populations of Lu. longipalpis. They demonstrate the importance of evaluating chemicals against this species by conventional bioassay and microplate assays before and during spraying programmes.