Radiometric studies of mycobacterium tuberculosis

An in vitro assay system that included automated radiometric quantification of 14CO2 released as a result of oxidation of 14C- substrates was applied for studying the metabolic activity of M. tuberculosis under various experimental conditions. These experiments included the study of a) mtabolic pathways, b) detection times for various inoculum sizes, c) effect of filtration on reproducibility of results, d) influence of stress environment e) minimal inhibitory concentrations for isoniazid, streptomycin, ethambutol and rifampin, and f) generation times of M. tuberculosis and M. bovis. These organisms were found to metabolize 14C-for-mate, (U-14C) acetate, (U-14C) glycerol, (1-14C) palmitic acid, 1-14C) lauric acid, (U-14C) L-malic acid, (U-14C) D-glucose, and (U-14C) D-glucose, but not (1-14C) L-glucose, (U-14C) glycine, or (U-14C) pyruvate to 14CO2. By using either 14C-for-mate, (1-14C) palmitic acid, or (1-14C) lauric acid, 10(7) organisms/vial could be detected within 24 48 hours and as few as 10 organisms/vial within 16-20 days. Reproducible results could be obtained without filtering the bacterial suspension, provided that the organisms were grown in liquid 7H9 medium with 0.05% polysorbate 80 and homogenized prior to the study. Drugs that block protein synthesis were found to have lower minimal inhibitory concentrations with the radiometric method when compared to the conventional agar dilution method. The mean generation time obtained for M. bovis and different strains of M. tuberculosis with various substrates was 9 ± 1 hours.

Gender influence on treatment of chronic hepatitis C genotype 1

INTRODUCTION: Although various studies have been published regarding the treatment of chronic hepatitis C (CHC) with peginterferon (Peg-IFN) and ribavirin, little is known regarding the real impact of gender on the characteristics that influence the effectiveness and safety of antiviral treatment for CHC patients. The objective of this study was to evaluate the influence of gender on HCV treatment outcomes. METHODS: A retrospective analytical study was conducted among selected carriers of CHC genotype 1, who were treated with Peg-IFN α-2b at a dose of 1.5 μg/kg or Peg-IFN α-2a at a dose of 180 μg/week plus a ribavirin dose of 1,000-1,250 mg/day, according to weight, between 2001 and 2007. RESULTS: Among 181 patients undergoing treatment, the mean age was 46.4 ± 11.0 years and 46% were women. At baseline, 32% of the patients had advanced fibrosis (F3-F4 Scheuer), and 83% of the subjects had viral load > 400,000 IU/ml, without significant difference between the genders (p = 0.428 and p = 0.452, respectively). When compared with men, women had higher incidence of many adverse events such as anemia (p < 0.001) and higher need for dose reduction, for both Peg-IFN (p = 0.004) and ribavirin (p = 0.006). However, the rate of sustained virological response (SVR) did not differ between the genders: 45% (female) vs 41% (male); p=0.464. CONCLUSIONS: This study suggests that women and men react differently to combined therapy, especially in relation to the incidence of adverse events and the need for dose modification. Nevertheless, these differences do not influence the SVR rate.

Absence of HTLV-1/2 infection and dermatological diseases in Manaus, State of Amazonas, Brazil

Introduction The prevalence of human T-cell lymphotropic virus types 1 and 2 (HTLV-1/2) infection is heterogeneous across different populations. We tested the hypothesis that HTLV-1/2 infection occurs more often in dermatological patients. Methods A total of 1,091 patients from a tropical dermatology clinic were tested for HTLV-1/2. In parallel, 6865 first-time blood donors from the same geographic area were screened for HTLV-1/2; HTLV-1/2 positive blood donors underwent dermatological examinations. Results The prevalence of HTLV-1/2 in first-time blood donors was 0.14%. No co-occurrence of HTLV-1/2 infection and dermatological conditions was observed. Conclusions Our results challenge the hypothesis that HTLV-1/2 infection occurs more often in dermatological patients.

Prevention of bone marrow graft failure by an anti LFA-1 monoclonal antibody

Graft rejection is the major cause of failure of HLA mismatched bone marrow transplantation because of residual host immunity. we have proposed to use a monoclonal murine antibody specific for the LFA-1 molecule (25-3) to prevent graft failure in HLA mismatched bone marrow transplantation (BMT). The rationale for this approach is three fold: LFA-1 deficient patients (3/3) do not reject HLA mismatched BMT; anti LFA-1 blocka in vitro the induction of T cell responses and T/ non T cytotoxic functions; LFA-1 is not expressed by other cells than leucocytes. We have accordingly treated twenty two patients with inherited diseases and 8 with leikemia. The bone marrow was T cells depled by E rosetting of Campath antibody. The antibody was given at days -3, -1, +1, +3, +5 at dose of .1 mg/kg/d for the first 9 and then .2mg/kg/d from day -3 to +6. Engraftment occured in 23/30 patients as shown by at least HLA typing. Hematological recovery was rapid, GVH was limited. Side effects of antibody infusion included fever and possibly an increased incidence of early bacteral infection (sepsis, 1 death). Immunological reconstitution occured slowly leading in six cases to EBV-induced B cell poliferation (1 death and in two others to transient auto immune hemolytic anemia. There has been only one secondary graft rejection. Sisteen patients are alive 3 to 26 months post transplant with functional grafts. Although the number of patients treated is still low the absence of late rejection so far, gives hope for long term maintenance of the graft using anti LFA-1. Since the antibody is an IgG 1 unable to bind human complement, and since it is known to inhibit phagocytosis, there is a good suggestion that 25-3 act through functional blocking of host T and non T luymphocytes at both induction and effector levels.

Stomach content analyses of Simulium perflavum Roubaud 1906 (Diptera: Simuliidae) larvae from streams in Central Amazônia, Brazil

Stomach contents of Simulium perflavum Roubaud larvae were analyzed and compared with plankton and periphyton collected in five streams, in Central Amazonia (Manaus and Presidente Figueiredo counties), in Sep./Oct.1996 (dry season) and Feb./Mar. 1997 (rainy season). A total of 1,400 last-instar larvae were dissected; the stomach contents were analyzed using different methods: fresh and after oxidation. A total of 87 taxa (algae, diatoms and rotifers) were found in the stomach contents. In each stream, qualitative samples of plankton and periphyton were collected; these were mounted between slides and cover slips. A total of 94 taxa of plankton and 54 taxa of periphyton were collected. One species of Rotifera was present in the stomach contents, plankton and periphyton. Cluster analysis based on species composition of the organisms present in the stomach contents grouped the streams into two major groups, each belonging to a different drainage area. Correlations based on presence/absence of species of microalgae in the stomach contents, plankton and periphyton indicated significant associations (p<0.05) between stomach contents and plankton and between plankton and periphyton (z test); the Sorensen coefficient and cluster analysis corroborate the same associations.

Molluscicidal action of the latex of Euphorbia splendens var. hislopii N.E.B. ("Christ's Crown") (Euphorbiaceae) against Lymnaea columella (Say, 1817) (Pulmonata: Lymnaeidae), intermediate host of Fasciola hepatica Linnaeus, 1758 (Trematode: Fasciolidae): 1- test in laboratory

The latex action of Euphorbia splendens var. hislopii (Christ's Crown) against snails Lymnaea columella, intermediate host of Fasciola hepatica, derived from irrigation ditches of the Station of Pisciculture at Universidade Federal Rural do Rio de Janeiro, was studied in the laboratory. Lab bioassays, using aqueous solutions of the latex, varying between 0.1 and 10 mg/l, have proven molluscicidal activity of the product collected on the same day the tests were performed, during the four seasons of the year, finding the following lethal concentrations (LC90): 1.51 mg/l in the spring; 0.55 mg/l in the summer; 0.74 mg/l in the fall and 0.93 mg/l in winter, after 24 h exposure of the snails, showing significant differences among the seasons of the year (ANOVA test, F = 11.01, G.L.= 3/33, p < 0.05), as well as among the concentrations (ANOVA test, F = 27.38, G.L.= 11/33, p < 0.05). In the summer, mortality reached 100% from concentration at 0.6 mg/l, the same during fall and in winter as of 1 mg/l, while in spring it only reached 100% mortality as of 2 mg/l. Mortality in the controls was low, reaching 5% in the summer and winter and 10% in the fall and spring. None of the samples died. During the assay, with an aqueous solution of the latex at a concentration of 5 mg/l, in order to check the time of duration of the product effect, in the laboratory, it was observed that the molluscicidal activity remained stable up to the 15th day after the beginning of the test with 100% mortality of L. columella, gradually losing its effect until the 23rd day, when we no longer observed animal mortality. In the control group, there was a random daily variation in mortality rate ranging 0-50% after 48 h of observation for 30 days.

Effect of CO2 and 1-octen-3-ol attractants for estimating species richness and the abundance of diurnal mosquitoes in the southeastern Atlantic forest, Brazil

Studies have shown that both carbon dioxide (CO2) and octenol (1-octen-3-ol) are effective attractants for mosquitoes. The objective of the present study was to evaluate the attractiveness of 1-octen-3-ol and CO2 for diurnal mosquitoes in the southeastern Atlantic forest. A Latin square experimental design was employed with four treatments: CDC-light trap (CDC-LT), CDC-LT and 1-octen-3-ol, CDC-LT and CO2 and CDC-LT with 1-octen-3-ol and CO2. Results demonstrated that both CDC-CO2 and CDC-CO2-1-octen-3-ol captured a greater number of mosquito species and specimens compared to CDC-1-octen-3-ol; CDC-LT was used as the control. Interestingly, Anopheles (Kerteszia) sp. was generally attracted to 1-octen-3-ol, whereas Aedes serratus was the most abundant species in all Latin square collections. This species was recently shown to be competent to transmit the yellow fever virus and may therefore play a role as a disease vector in rural areas of Brazil.

Inferences about the global scenario of human T-cell lymphotropic virus type 1 infection using data mining of viral sequences

Human T-cell lymphotropic virus type 1 (HTLV-1) is mainly associated with two diseases: tropical spastic paraparesis/HTLV-1-associated myelopathy (TSP/HAM) and adult T-cell leukaemia/lymphoma. This retrovirus infects five-10 million individuals throughout the world. Previously, we developed a database that annotates sequence data from GenBank and the present study aimed to describe the clinical, molecular and epidemiological scenarios of HTLV-1 infection through the stored sequences in this database. A total of 2,545 registered complete and partial sequences of HTLV-1 were collected and 1,967 (77.3%) of those sequences represented unique isolates. Among these isolates, 93% contained geographic origin information and only 39% were related to any clinical status. A total of 1,091 sequences contained information about the geographic origin and viral subtype and 93% of these sequences were identified as subtype “a”. Ethnicity data are very scarce. Regarding clinical status data, 29% of the sequences were generated from TSP/HAM and 67.8% from healthy carrier individuals. Although the data mining enabled some inferences about specific aspects of HTLV-1 infection to be made, due to the relative scarcity of data of available sequences, it was not possible to delineate a global scenario of HTLV-1 infection.

Conservation of 'Pedro Sato' guavas under treatment with 1-methylcyclopropene

The search for techniques that extend shelf life of guava (Psidium guajava) fruits, and reduce its postharvest losses is desirable. The objective of this work was to evaluate the effects of concentrations of competitive ethylene antagonist 1-methylcyclopropene (1-MCP) on conservation of 'Pedro Sato' guava fruits. Treatments consisted of 0, 100, 300 or 900 nL L-1 of 1-MCP for 3 hours followed by storage at 25ºC, and 10ºC with 90±5% RH. The application of 900 nL L-1 1-MCP for 3 hours was efficient in delaying loss of skin color, and in keeping fruit firmness at both storage temperatures. The 300 nL L-1 of 1-MCP concentration was efficient in delaying skin color loss only when fruits were stored at 10ºC. The effect of 1-MCP was quite significant on the reduction of rot incidence at both storage temperatures. The respiratory rate was lower in fruits treated with 300 and 900 nL L-1 of 1-MCP during storage at 25ºC. The product was efficient in delaying the ripening of fruits, and the concentration of 900 nL L-1 showed the best effect.

Enzyme activities and pectin breakdown of sapodilla submitted to 1-methylcyclopropene

The objective of this work was to investigate the influence of 1-methylcyclopropene (1-MCP) at 300 nL L-1 on activities of cell wall hidrolytic enzymes and pectin breakdown changes which Sapodilla (Manilkara zapota cv. Itapirema 31) cell wall undergoes during ripening. Sapodilla were treated with ethylene antagonist 1-MCP at 300 nL L-1 for 12 hours and then, stored under a modified atmosphere at 25º C for 23 days. Firmness, total and soluble pectin and cell wall enzymes were monitored during storage. 1-MCP at 300 nL L-1 for 12 hours delayed significantly softening of sapodilla for 11 days at 25º C. 1-MCP postharvest treatment affected the activities of cell wall degrading enzymes pectinmethylesterase and polygalacturonase and completely suppressed increases in beta-galactosidase for 8 days, resulting in less pectin solubilization. Beta-galactosidase seems relevant to softening of sapodilla and is probably responsible for modification of both pectin and xyloglucan-cellulose microfibril network.

Dimetildioxirano. 1. Oxidação de compostos de enxofre

A brief review of the chemistry of dimethyldioxirane is presented. This article specifically foccus on the preparation of dimethyldioxirane, its chemical reactivity, and specially on the oxidation of sulfur compounds.

Iron oxide and pyrocatechol: a spectroscopy study of the reaction products

The reaction of 1,2-dihydroxy-benzene (pyrocatechol) (C6H6O2) with iron oxide (Fe2O3) and sodium thiosulfate (Na2S2O3) in aqueous medium (pH 7) was investigated. Pyrocatechol suffers autoxidation and coordinates with Fe3+ in solution. The presence of S2O3(2-) in solution was fundamental to generate and stabilize the pyrocatechol oxidation products as o-semiquinones. This compound was isolated and its structure characterized using FT-IR, EPR and UV-Vis Spectroscopy as [CTA][Fe(SQ)2(Cat)]. A thermal mass loss mechanism was proposed based on Thermogravimetric Analysis (TG) to support the structural characterization.

Flow-injection spectrophotometric determination of tetracycline and doxycycline in pharmaceutical formulations using chloramine-T as oxidizing agent

A flow-injection (FI) spectrophotometric procedure is proposed for tetracycline (TC) and doxycycline (DXC) determination in pharmaceuticals. The method is based on the reaction of oxidation of these drugs by chloramine-T in alkaline medium producing red color products (λmax = 535 and 525 nm). Beer´s law is obeyed in the concentration range from 6.62 x 10-5 to 7.72 x 10-4 mol L-1 and 5.37 x 10-5 to 7.16 x 10-4 mol L-1 for TC and DXC, respectively. The analytical frequency was 50 h"1 and 45 h-1 for TC and DXC, respectively. The results obtained by the proposed method were in good agreement with those obtained by the official method at 95% confidence level.

Preliminary study of insect attraction by a mixture of semiochemicals containing 1,2,4-Trimethoxybenzene in domestic citric-culture

In this work we describe a new efficient strategy for the preparation of 1,2,4-trimethoxybenzene (3) in 56% overall yield. The compound 3 was used in a preliminary study of insect attraction by a mixture of semiochemicals called TIV, composed of indol (1), vanillin (2) and 1,2,4-trimethoxybenzene (3), in eight Mc Phail style traps installed at a domestic orchard of citric-culture, containing 120 trees not infected by plagues in Bom Jesus Farm, located next to a patch of the Atlantic Forest, at Silva Jardim, Rio de Janeiro, Brazil.

Utilization of Sn/Nb2O5 composite for the removal of methylene blue

In this work, the oxidation of methylene blue textile dye in the presence of hydrogen peroxide, using niobium oxide impregnated with different proportions of tin (1, 5 and 10% in mass) as catalyst was studied. The materials were characterized by TPR, XPS, XRD and FTIR. The oxidation tests monitored by ESI-MS showed that the composite containing the higher amount of tin was the most efficient in the removal of the dye. The XRD, XPS, and TPR data presented evidence of the formation of the tin-niobium oxide composite containing Sn0 and supported SnO2.