Efeito da fração não-oleosa doRicinus communisna biodistribuição comTecnécio-99m em camundongos / Effect of non-oily fraction ofRicinus communis on the bio distribution with Technetium-99m in mice

RESUMO Ricinus communisé uma planta pertence à família Euforbiaceae. A partir de seus frutos é extraído o óleo de rícino e outra fração altamente tóxica (fração não-oleosa). Neste estudo, foi avaliado o efeito da fração não oleosa de R. communis(FNORC) na biodistribuição do Tc-99m em camundongos sadios e em animais transplantados com Sarcoma-180 (S180). Para avaliação da biodistribuição do Tc-99m, o percentual de atividade radioativa total injetada (ATI%) foi mensurada utilizando um contador gama. Os resultados mostraram que, em animais sadios, houve aumento da captação do Tc-99m após o tratamento com FNORC pelos rins, cérebro e estômago. Apenas houve diminuição da absorção deste radioisótopo nos músculos. Em animais com tumor, houve redução significativa da captação do Tc-99m no coração, pulmões e tumor, e foi observado o aumento da captação apenas nos rins. Foi observada também a diminuição da concentração das proteínas plasmáticas totais em animais com tumor após tratamento com FNORC e atividade antitumoral significativa. Diante desses dados, conclui-se que fração não oleosa de R. communis possui atividade antitumoral significativa, porém altera a biodistribuição do Tc-99m, fato este que pode resultar em falhas nos processos de diagnóstico por imagem que utilizem este radioisótopo como marcador.

ABSTRACT Ricinus communis is a plant belonging to the Euforbiaceae family. From its fruits, it is extracted the castor oil and another highly toxic fraction (non-oily fraction). In this study, we evaluated the effect of the non-oily fraction of R. communis (NOFRC) on the bio distribution of Tc-99m in healthy mice and in animals transplanted with Sarcoma-180 (S180). To evaluate the bio distribution of theTc-99m, the percentage of the total injected radioactivity (% TIR) was measured through a gamma counter. There was an increase in the capitation of Tc-99m after the treatment with NOFRC in the kidneys, brain, and stomach of healthy animals. A decrease in the reception of this radionuclide was only found in the muscles. In animals with tumour, there was a significant reduction in the uptake of Tc-99m in the heart, lungs and tumour. An increase in the capitation was only observed in the kidneys. It was also observed a reduction in the total plasma protein concentration in animals with tumours after the treatment with NOFRC, besides significant antitumor activity. We concluded that there is antitumor activity in the NOFRC, but that it alters the biodistribution of Tc-99m, a fact which may result in failures in the diagnostic imaging process using this radioisotope as a marker.

Aspartic peptidases of human pathogenic trypanosomatids: perspectives and trends for chemotherapy.

Aspartic peptidases are proteolytic enzymes present in many organisms like vertebrates, plants, fungi, protozoa and in some retroviruses such as human immunodeficiency virus (HIV). These enzymes are involved in important metabolic processes in microorganisms/virus and play major roles in infectious diseases. Although few studies have been performed in order to identify and characterize aspartic peptidase in trypanosomatids, which include the etiologic agents of leishmaniasis, Chagas' disease and sleeping sickness, some beneficial properties of aspartic peptidase inhibitors have been described on fundamental biological events of these pathogenic agents. In this context, aspartic peptidase inhibitors (PIs) used in the current chemotherapy against HIV (e.g., amprenavir, indinavir, lopinavir, nelfinavir, ritonavir and saquinavir) were able to inhibit the aspartic peptidase activity produced by different species of Leishmania. Moreover, the treatment of Leishmania promastigotes with HIV PIs induced several perturbations on the parasite homeostasis, including loss of the motility and arrest of proliferation/growth. The HIV PIs also induced an increase in the level of reactive oxygen species and the appearance of irreversible morphological alterations, triggering parasite death pathways such as programed cell death (apoptosis) and uncontrolled autophagy. The blockage of physiological parasite events as well as the induction of death pathways culminated in its incapacity to adhere, survive and escape of phagocytic cells. Collectively, these results support the data showing that parasites treated with HIV PIs have a significant reduction in the ability to cause in vivo infection. Similarly, the treatment of Trypanosoma cruzi cells with pepstatin A showed a significant inhibition on both aspartic peptidase activity and growth as well as promoted several and irreversible morphological changes. These studies indicate that aspartic peptidases can be promising targets in trypanosomatid cells and aspartic proteolytic inhibitors can be benefic chemotherapeutic agents against these human pathogenic microorganisms.

Biokinetics and dosimetric studies about 99mTc(V)-DMSA distribution.

Research for radiodiagnostic agents should considerate biological critical parameters which will give own contribution on the absorbed dose. The dimercaptosuccinic acid (DMSA) labeled with (99m)Tc(V) is a radiopharmaceutical which has well established role in medullar thyroid carcinoma and has been proposed in evaluation of bone metastasis. This work studied the biokinetics and dosimetry of (99m)Tc(V)-DMSA by animal model. The (99m)Tc(V)-DMSA was prepared from a (III)DMSA kit alkalized. Mice (n=5) received (99m)Tc(V)DMSA i.v., they were sacrificed (30 min, 1h, 5h and 12h), the organs excised and the activities measured by a gamma counter. The results were evaluated based on %activity/g and the absorbed dose was estimated (MIRDOSE 3.0 program) by extrapolation of data from animal to human scale. The results showed the majority of organs reached the top uptake at 30 min, the greatest kidney uptake was (4.81 +/- 1.38)% activity/g, while the bone presented its highest uptake at 1h (5.49+/- 0.47)% activity/g, after 1h all the organs had activity exponential decrease. The biokinetic profile of (99m)Tc(V)-DMSA was well established, allowing quantifying of residence time, and the radiation dose estimates were made for this agent. About the absorbed dose, the preliminary results showed higher value to bone, being the soft tissue dose relatively low.

Effects of the electromagnetic field, 60 Hz, 3 microT, on the hormonal and metabolic regulation of undernourished pregnant rats.

Epidemiological studies have implicated maternal protein-calorie deficiency as an important public health problem in developing countries. Over the last decades, a remarkable diffusion of electricity and an increased level of the electromagnetic field (EMF) in the environment have characterized modern societies. Therefore, researchers are concerned with the biological effects of 50-60 Hz, EMF. The aim of this paper is to show the effects of EMF of 60 Hz, 3 muT, exposure for two hours per day in the regulation of the hormonal and metabolic concentrations in pregnant rats, which were fed by Regional Basic Diet (RBD) during their pregnancy as compared with pregnant rats fed a standard diet. Pregnant rats exposed to EMF of 60 Hz, 3 muT, over the pregnancy and fed with RBD presented an increase in glucose release when compared with the Group subjected only to the RBD ration. Rats fed RBD presented a decrease in their insulin and cortisol serum levels when compared with the Group fed with casein. The T3 and T4 concentrations presented the greatest variation among the Groups. The relation T4:T3 was much exaggerated in the Group subjected to RDB and exposed to EMF when compared to the others. In conclusion, the group subjected to the association of EMF and undernutrition suffered a decrease in its serum concentration of T4 and T3 when compared to the well-nourished group and the relationship T4:T3 in the former group was almost eighteen-fold the later one.

Effects of the Electromagnetic field, 60 Hz, 3 µT, on the hormonal and metabolic regulation of undernourished pregnant rats / Efeitos do campo eletromagnético, 60 Hz, 3µT, na regulação hormonal e metabólica de ratas prenhes desnutridas

Epidemiological studies have implicated maternal protein-calorie deficiency as an important public health problem in developing countries. Over the last decades, a remarkable diffusion of electricity and an increased level of the electromagnetic field (EMF) in the environment have characterized modern societies. Therefore, researchers are concerned with the biological effects of 50-60 Hz, EMF. The aim of this paper is to show the effects of EMF of 60 Hz, 3 μT, exposure for two hours per day in the regulation of the hormonal and metabolic concentrations in pregnant rats, which were fed by Regional Basic Diet (RBD) during their pregnancy as compared with pregnant rats fed a standard diet. Pregnant rats exposed to EMF of 60 Hz, 3 μT, over the pregnancy and fed with RBD presented an increase in glucose release when compared with the Group subjected only to the RBD ration. Rats fed RBD presented a decrease in their insulin and cortisol serum levels when compared with the Group fed with casein. The T3 and T4 concentrations presented the greatest variation among the Groups. The relation T4:T3 was much exaggerated in the Group subjected to RDB and exposed to EMF when compared to the others. In conclusion, the group subjected to the association of EMF and undernutrition suffered a decrease in its serum concentration of T4 and T3 when compared to the well-nourished group and the relationship T4:T3 in the former group was almost eighteen-fold the later one.

Estudos epidemiológicos têm mostrado que a deficiência proteico-calórica é um importante problema nos países em desenvolvimento. Durante as últimas décadas, a sociedade moderna tem sido caracterizada pelo aumento no número de equipamentos elétricos e como consequência um aumento no nível do campo eletromagnético (CEM) no ambiente. No entanto, os pesquisadores estão preocupados com os efeitos biológicos dos CEM de 50-60 Hz. O objetivo deste artigo é mostrar os efeitos do CEM de 60 Hz, 3 μT, nas concentrações hormonais e metabólicas de ratas prenhes, expostas duas horas por dia ao CEM, alimentadas pela Dieta Básica Regional (DBR) comparando com ratas submetidas às mesmas condições, mas alimentas com dieta padrão. Ratas prenhes expostas ao CEM de 60 Hz, 3 μT, durante a prenhez e alimentadas com a DBR apresentaram um aumento na liberação de glicose quando comparadas com o grupo alimentado pela DBR sem CEM. As ratas alimentadas pela DBR apresentaram uma diminuição nos níveis de insulina e cortisol quando comparadas com o grupo alimentado pela caseína. As concentrações de T3 e T4 apresentaram a maior variação entre os grupos. A relação T4:T3 foi muito exagerada no grupo alimentado pela DBR e exposto ao CEM quando comparado com os outros. Conclusão, os animais que foram submetidos à desnutrição e ao CEM sofreram uma diminuição na concentração sérica de T4 e T3 quando comparados com os animais bem nutridos e a relação T4:T3 no primeiro grupo foi quase 18 vezes a relação de T4:T3 no grupo bem nutrido.

Influence of a 60 Hz, 3 microT, electromagnetic field on the somatic maturation of wistar rat offspring fed a regional basic diet during pregnancy.

The aim of the present study was to observe how the exposition of pregnant rats to an electromagnetic field (EMF), with frequency of 60 Hz, and a magnetic field of 3 microT for 2 hours per day and/or using the so-called Regional Basic Diet (RBD), influenced the somatic maturation in their offspring. Four groups were formed: Group A (casein), B (casein and EMF), C (RBD) and D (RBD and EMF). The diet manipulation occurred during pregnancy. The somatic maturation indexes--assessed daily between 12:00 AM and 2:00 PM--were: Eye Opening (EO), Auricle Opening (AO), Auditory Canal Opening (ACO), Low Incisor Eruption (LIE), and Upper Incisor Eruption (UIE). The association between EMF and deficient diet caused a delay in all Somatic Maturation Indexes (SMI) and the RBD caused delay only in the AO. Furthermore, the EMF caused delay in AO, ACO, LIE. In relation to the body weight, the EMF associated with the deficient diet caused change in the twenty-first day of life. The RBD, during pregnancy, caused lower body weight in the offspring in the first and third day of life. The body weight of the offspring whose mothers were fed casein and exposed to the EMF during pregnancy was lower in the third and sixth day of life. In conclusion, the EMF associated with under-nutrition caused delay in all SMI. In relation to the body weight, the EMF associated with under-nutrition caused a decrease in the body weight at the sixth day of life.

Influence of a 60 Hz, 3 µT, electromagnetic field on the somatic maturation of wistar rat offspring fed a regional basic diet during pregnancy / Influência do campo eletromagnético de 60 Hz, 3 µT, na maturação somática de filhotes de ratos wistar alimentados pela dieta básica regional durante a prenhez

The aim of the present study was to observe how the exposition of pregnant rats to an electromagnetic field (EMF), with frequency of 60 Hz, and a magnetic field of 3 µT for 2 hours per day and/or using the so-called Regional Basic Diet (RBD), influenced the somatic maturation in their offspring. Four groups were formed: Group A (casein), B (casein and EMF), C (RBD) and D (RBD and EMF). The diet manipulation occurred during pregnancy. The somatic maturation indexes - assessed daily between 12:00 AM and 2:00 PM - were: Eye Opening (EO), Auricle Opening (AO), Auditory Canal Opening (ACO), Low Incisor Eruption (LIE), and Upper Incisor Eruption (UIE). The association between EMF and deficient diet caused a delay in all Somatic Maturation Indexes (SMI) and the RBD caused delay only in the AO. Furthermore, the EMF caused delay in AO, ACO, LIE. In relation to the body weight, the EMF associated with the deficient diet caused change in the twenty-first day of life. The RBD, during pregnancy, caused lower body weight in the offspring in the first and third day of life. The body weight of the offspring whose mothers were fed casein and exposed to the EMF during pregnancy was lower in the third and sixth day of life. In conclusion, the EMF associated with under-nutrition caused delay in all SMI. In relation to the body weight, the EMF associated with under-nutrition caused a decrease in the body weight at the sixth day of life.

O objetivo deste estudo foi observar a influência do campo eletromagnético (CEM), com freqüência de 60Hz, campo magnético de 3 µT, durante 2 horas por dia, associado ou não à dieta básica regional (DBR) no desenvolvimento somático da prole. Quatro grupos foram formados: Grupo A (caseína), B (caseína e CEM), C (DBR) e D (DBR e CEM). A manipulação dietética ocorreu durante a prenhez. Os índices de maturação somática - Abertura dos Olhos (AO), Abertura do Pavilhão Auditivo (APA), Abertura do Conduto Auditivo (ACA), Erupção do Incisivo Inferior (EII), e Erupção do Incisivo Superior (EIS) - foram avaliados diariamente entre 12 e 14 horas. A associação entre o CEM e a dieta deficiente causou retardo em todos os índices de maturação somática (IMS) e a DBR causou retardo somente na APA. O CEM causou retardo na APA, ACA, EII. Em relação ao peso corporal, o CEM associado à dieta deficiente causou mudanças no 21º dia de vida. A DBR, durante a prenhez, causou diminuição do peso corporal dos filhotes no 1º e no 3º dia de vida. O peso corporal dos filhotes, cujas mães foram alimentadas pela caseína e expostas ao CEM, durante a prenhez, apresentaram uma diminuição no 3º e 6º dia de vida. Conclusão: o CEM, associado com a desnutrição, causou retardo em todos os IMS. Em relação ao peso corporal, o CEM, associado à desnutrição, causou uma diminuição no peso corporal no 6º dia de vida.

GenoMycDB: a database for comparative analysis of mycobacterial genes and genomes

Several databases and computational tools have been created with the aim of organizing, integrating and analyzing the wealth of information generated by large-scale sequencing projects of mycobacterial genomes and those of other organisms. However, with very few exceptions, these databases and tools do not allow for massive and/or dynamic comparison of these data. GenoMycDB (http://www.dbbm.fiocruz.br/GenoMycDB) is a relational database built for large-scale comparative analyses of completely sequenced mycobacterial genomes, based on their predicted protein content. Its central structure is composed of the results obtained after pair-wise sequence alignments among all the predicted proteins coded by the genomes of six mycobacteria: Mycobacterium tuberculosis (strains H37Rv and CDC1551), M. bovis AF2122/97, M. avium subsp. paratuberculosis K10, M. leprae TN, and M. smegmatis MC2 155. The database stores the computed similarity parameters of every aligned pair, providing for each protein sequence the predicted subcellular localization, the assigned cluster of orthologous groups, the features of the corresponding gene, and links to several important databases. Tables containing pairs or groups of potential homologs between selected species/strains can be produced dynamically by user-defined criteria, based on one or multiple sequence similarity parameters. In addition, searches can be restricted according to the predicted subcellular localization of the protein, the DNA strand of the corresponding gene and/or the description of the protein. Massive data search and/or retrieval are available, and different ways of exporting the result are offered. GenoMycDB provides an on-line resource for the functional classification of mycobacterial proteins as well as for the analysis of genome structure, organization, and evolution.

Cholesterol-dependent hemolytic activity of Passiflora quadrangularis leaves.

Plants used in traditional medicine are rich sources of hemolysins and cytolysins, which are potential bactericidal and anticancer drugs. The present study demonstrates for the first time the presence of a hemolysin in the leaves of Passiflora quadrangularis L. This hemolysin is heat stable, resistant to trypsin treatment, has the capacity to froth, and acts very rapidly. The hemolysin activity is dose-dependent, with a slope greater than 1 in a double-logarithmic plot. Polyethylene glycols of high molecular weight were able to reduce the rate of hemolysis, while liposomes containing cholesterol completely inhibited it. In contrast, liposomes containing phosphatidylcholine were ineffective. The Passiflora hemolysin markedly increased the conductance of planar lipid bilayers containing cholesterol but was ineffective in cholesterol-free bilayers. Successive extraction of the crude hemolysin with n-hexane, chloroform, ethyl acetate, and n-butanol resulted in a 10-fold purification, with the hemolytic activity being recovered in the n-butanol fraction. The data suggest that membrane cholesterol is the primary target for this hemolysin and that several hemolysin molecules form a large transmembrane water pore. The properties of the Passiflora hemolysin, such as its frothing ability, positive color reaction with vanillin, selective extraction with n-butanol, HPLC profile, cholesterol-dependent membrane susceptibility, formation of a stable complex with cholesterol, and rapid erythrocyte lysis kinetics indicate that it is probably a saponin.

Cholesterol-dependent hemolytic activity of Passiflora quadrangularis leaves

Plants used in traditional medicine are rich sources of hemolysins and cytolysins, which are potential bactericidal and anticancer drugs. The present study demonstrates for the first time the presence of a hemolysin in the leaves of Passiflora quadrangularis L. This hemolysin is heat stable, resistant to trypsin treatment, has the capacity to froth, and acts very rapidly. The hemolysin activity is dose-dependent, with a slope greater than 1 in a double-logarithmic plot. Polyethylene glycols of high molecular weight were able to reduce the rate of hemolysis, while liposomes containing cholesterol completely inhibited it. In contrast, liposomes containing phosphatidylcholine were ineffective. The Passiflora hemolysin markedly increased the conductance of planar lipid bilayers containing cholesterol but was ineffective in cholesterol-free bilayers. Successive extraction of the crude hemolysin with n-hexane, chloroform, ethyl acetate, and n-butanol resulted in a 10-fold purification, with the hemolytic activity being recovered in the n-butanol fraction. The data suggest that membrane cholesterol is the primary target for this hemolysin and that several hemolysin molecules form a large transmembrane water pore. The properties of the Passiflora hemolysin, such as its frothing ability, positive color reaction with vanillin, selective extraction with n-butanol, HPLC profile, cholesterol-dependent membrane susceptibility, formation of a stable complex with cholesterol, and rapid erythrocyte lysis kinetics indicate that it is probably a saponin.

Assessment of the effect of Punica granatum (pomegranata) on the bioavailability of the radiopharmaceutical sodium pertechnetate (99mTc) in Wistar rats.

The many desirable characteristics of technetium-99m (99mTc) have stimulated the development of labeling techniques for different molecular and cellular structures. It is generally accepted that a variety of factors other than disease can alter the bioavailability of radiopharmaceuticals and one such factor is the drug therapy. The use of medicinal plants has increased in the last decades all over the world. Punica granatum (pomegranata) is used as food or as medication in folk medicine for antiviral, anthelmintic, antifungal, antibacterial and antimicrobial activity. We have studied in rats, the effect of the medicinal plant Punica granatum on the bioavailability of the radiopharmaceutical 99mTc-sodium pertechnetate (Na(99m)TcO4). The infusion of pomegranata was administered by intragastric via into Wistar rats during seven days. After that, the animals received by ocular plexus via, 0.1 ml of the Na(99m)TcO4 (3.7MBq) and the animals were rapidly sacrificed after 5, 20 and 40 min. The organs were isolated (brain, heart, thyroid, liver, lungs, kidneys, stomach, testis, intestines, pancreas, spleen, bladder, muscle and bone), the radioactivity determined in a well counter, the percentages of radioactivity (%ATI) in the organs were calculated and statistical analyses were performed by Wilcoxon test (p < 0.05). The results have shown a significant (p < 0.05) increase of the activity of the Na(99m)TcO4 in spleen, heart, stomach, liver, stout bowel, pancreas, lungs and testis at 5 min. Twenty minutes after the administration of the radiopharmaceutical, the analysis of the results reveals a significant (p < 0.05) increase of the %ATI in heart, stomach, femur, pancreas, lungs and kidneys. Forty minutes after the administration of the Na(99m)TcO4, the results show a significant (p < 0.05) increase in spleen, brain, heart, stomach, liver, stout bowel, muscle, femur, lungs, pancreas, kidneys and testis. These results can be justified by therapeutic effect of this extract and/or by generation of active metabolites capable to interfere with the biodistribution of the studied radiopharmaceutical.

Evaluation of the phytic acid effect on the labeling of blood elements with technetium-99m and on the survival of a strain of Escherichia coli treated with stannous fluoride.

The labeling of red blood cells with technetium-99m (99mTc) depends on a reducing agent and stannous ions, as chloride or fluoride, are widely utilized. This labeling may also be altered by drugs. Moreover, some authors have reported that the survival of Escherichia coli (E. coli) cultures decreases in presence of stannous ions. Phytic acid is present in the daily diet and we evaluated its influence on: (i) the labeling of blood elements with 99mTc and (ii) on the survival of an E. coli strain treated with stannous fluoride. Heparinized whole blood was withdrawn from Wistar rats and it was incubated with stannous chloride and with 99mTc, as sodium pertechnetate, centrifuged and plasma (P) and blood cells (BC) were isolated. Samples of P and BC were also precipitated with trichloroacetic acid, centrifuged and soluble (SF) and insoluble fractions (IF) isolated. E. coli culture was treated with stannous fluoride in presence of phytic acid. As phytic acid altered the fixation of 99mTc on BC, on IF-P and on IF-BC and, moreover, it abolished the lethal effect of stannous fluoride on the E. coli culture, we can suggest that, probably, phytic acid would have chelating properties to the stannous ions.

Assessment of the effect of Fucus vesiculosus extract on the labeling of blood constituents with technetium-99m and the histological modifications on the shape of the red blood cells.

Natural products are widely used as food or food additives or medicines for humans. We are trying to develop a model to assess the possible toxic properties of natural products, such as Fucus vesiculosus, utilized in popular medicine. Red blood cells (RBC) labeled with technetium-99m (99mTc) are used in various procedures in nuclear medicine. This labeling procedure depends on a reducing agent, and stannous chloride is used. There is evidence that this labeling may be altered by drugs. We have investigated the possibility that F. vesiculosus extract is capable of altering the labeling of blood elements with 99mTc. Blood was incubated with F. vesiculosus extract and stannous chloride solution and Tc-99m added. Blood was centrifuged and plasma (P) and blood cells (BC) were isolated. Samples of P or BC were also precipitated, centrifuged and insoluble (IF) and soluble (SF) were separated. The percentages of radioativity (%ATI) in BC, IF-P and IF-BC were calculated. Histological preparations of the RBC treated with F. vesiculosus revealed that this extract is capable of promoting important modifications on the shape of the RBC. The%ATI decreased on BC from 93.6+/-2.3 to 29.0+/-2.7, on IF-P from 77.6+/-1.2 to 7.5+/-1.0 and on IF-BC from 80.0+/-3.4 to 12.6+/-4.8. Once the RBC labeling procedure with 99mTc depends on the presence of stannous (+2) ions, the substances present in the F. vesiculosus extract should increase the valence of these ions to stannic (+4). This would decrease the%ATI on blood elements and indicate the presence of oxidant agents in the F. vesiculosus extract.

Effects of the glucantime on the kinetic of biodistribution of radiopharmaceuticals in Wistar rats.

There are evidences that some drugs used for the human diseases can modify the biodistribution of radiopharmaceuticals. The N-methyl meglumine antimoniate, commercially known as glucantime (Rhodia, Brazil), is the elected drug for the treatment of all the clinical forms of leishmaniasis. As therapeutic drugs can present important toxic effects, we studied the effects of the glucantime on the kinetic of biodistribution of radiopharmaceuticals. To study the glucantime effect on the biodistribution of technetium-99m-methylenediphosphonic acid (99mTc-MDP), glucantime IM (80 mg/kg/day) was administered into male Wistar rats (3 months old age) in single dose during 7 days. 99mTc-MDP was injected 1 hr after the last dose. The animals (n = 24) were divided into two groups: treated (n = 12) and control (n = 12) and they were rapidly sacrificed, respectively, in 3 periods (5, 30 and 120 min) after administration of the 99mTc-MDP. The organs were isolated (brain, heart, thyroid, lungs, kidneys, testis, stomach, intestines, pancreas, spleen, liver, muscle, bone and bladder) and the percentages of radioactivity (%ATI) in each organ were calculated. The results were analyzed by the Wilcoxon test (p < 0.05). The analysis of the results has shown a significant increase of the %ATI after 5 min administration of the 99mTc-MDP in spleen, kidneys, testis, heart, liver and a reduction of %ATI in bladder. Thirty minutes after administration of the 99mTc-MDP, the analysis ofthe results reveals a significant reduction of the %ATI in femur, kidneys, thin bowel, lungs, heart, liver and an increase in abdominal muscle and stout bowel. One hundred-twenty min after administration of the 99mTc-MDP, the analysis of the results shows a significant reduction of the %ATI in spleen, thyroid, blood, femur, kidneys, liver and an increase in bladder, pancreas and lungs. Biochemical dosages were also performed before (control group, n = 12) and after (treated group, n = 12) treatment with glucantime. There was a significant (p < 0.05) decrease to the biochemical levels after the treatment with glucantime in following dosages: blood urea nitrogen, creatinine, alkaline phosphatase, lactic dehydrogenase, aspartate amino transferase, total creatine kinase, total protein, globulin and albumin. These results were compared with the control group, without glucantime, and statistical analyses were performed (t-student test, p < 0.05). These results could be associated with the biological effects and/or metabolization of the studied drug.

Assessment of the stannous fluoride and phytic acid effect in the yeast Saccharomyces cerevislae.

Stannous fluoride (SnF2) is a powerful reducing agent in 99mTc-labelled radiopharmaceuticals for nuclear medicine procedures. SnF2 may enhance reactive oxidative species (ROS) in prokaryotic cells. Phytic acid (PA) is a wide-ranging regulator of many important cellular functions such as intracellular regulations of surface receptions channels and it is known to have antioxidant and chelating properties. In order to analyze whether membrane transporters of the facilitator or the ABC type (SNQ1 and SNQ2) have an influence on Sn2+ toxicity in yeast we used the respective mutants and compared their responses to the wild type (WT). Since ABC transporters are YAP1p transcription activator inducible, we included a yap1 mutant in our Sn2+ toxicity assay. Finally, we tested the PA influence on Sn2+ toxicity in these strains. Yeast cells in stationary growth phase were exposed to different concentrations of SnF2 (ranging from 2 to 6 mg/ml) and PA (0.1 M) for one hour. The snq1 mutant exhibited the highest sensitivity to SnF2 while the snq2 and snq3/yap1 mutants had an equally intermediate sensitivity. The presence of PA was not able to produce a significant protection against the cytotoxicity of SnF2. This is probably due to its reduced chelating power in complex liquid media Our results with yeast support the genotoxic effects described for SnF2 in bacteria andindicate that the biological effect of this reducing agent could be related to the generation of reactive oxygen species.

Bovine cumulus/oocyte complex: quantification of LH/hCG receptors.

LH/hCG receptors of the bovine cumulus/oocyte complex were quantified, and their maximum binding capacities and affinity constants were determined by Scatchard analysis. Specific binding of these gonadotropins to receptors in follicles of different sizes was also determined by radiolabeling techniques. A greater number of receptors was observed to be bound to LH than to hCG (P < 0.05); however, affinity constants did not significantly differ (P > 0.05). The results of specific binding of the gonadotropins presented differences in relation to follicle size. Differences in the specific binding values of LH and hCG were verified (P < 0.05), but when submitted to linear regression analysis, presented similar behaviors in relation to follicle size. It is concluded that receptors of bovine cumulus/oocyte complex cells bind specifically to LH/hCG, that binding capacity is inversely proportional to follicle size, and that the behavior of hCG is similar to that of LH, suggesting that hCG can also promote the maturation of bovine oocytes when used in concentrations greater than LH.

Growth changes induced by gamma radiation on Biomphalaria straminea (Dunker, 1848).

Doses of 60Co gamma radiation with 2.5; 5; 7.5; 10; 15; 20; 25; 30; 35; 40; 45; 50; 55; 60; 80; 160; 320 and 640 Gy were applied to 1, 080 snails Biomphalaria straminea, an intermediate host of Schistosoma mansoni, divided in groups containing 30 mollusks. In addition, 60 non irradiated snails were kept as control. Fifty percent of the population was kept in colonies (allowing cross fertilization) while the other half was maintained in sexual isolation (allowing self fertilization) and during one month their growth was observed through the daily measurement of the shell diameter. Results showed that after 20 Gy doses the growth in shell diameter of irradiated snails was greater than that of the control group after 30 days. At this dose the snail size was the greatest, among all isolated groups. The 80 Gy doses also induced the final shell diameter of isolated snails to be greater then that observed in the control groups. As this effect was most evident among the isolated snails, a possible hormonal role may have been involved in the observed phenomena, which is under investigation with the objective of identifying any future applications that this could have to schistosomiasis control.

Minicircle variable region probes for characterization of Leishmania (Viannia) species.

The minicircle molecules present in the kinetoplast DNA (kDNA) network constitute a particularly useful molecular tool because they are a multicopy target and present a variable region that differs among minicircle classes in the same network. Using the polymerase chain reaction (PCR) and a set of primers directed outwardly from the minicircle conserved region, it is possible to prepare molecular probes representing the pool of variable regions from the different minicircle classes in the kDNA. In order to examine the specificity of the minicircle variable region as hybridization probes in Leishmania (Viannia) species, such fragments were amplified from reference strains and from a panel of isolates representing the zymodeme diversity of Leishmania (Viannia) in Colombia. The size of the amplified products was conserved in Leishmania (Viannia) braziliensis, Leishmania (Viannia) guyanensis, and Leishmania (Viannia) panamensis (650 bp) and diverged in Leishmania (Viannia) equatorensis and Leishmania (Viannia) colombiensis (850 bp). The amplified products were further hybridized to variable region pools of Leishmania braziliensis, Leishmania panamensis, Leishmania guyanensis, and Leishmania equatorensis reference strains. The results obtained from the hybridization experiments support this approach as a means of defining relationships among strains. Hybridization allowed homologies to be perceived, whereas restriction fragment length analysis of the amplified products yielded strain-specific profiles. Apparently, L. (V.) equatorensis and L. (V.) colombiensis minicircle variable regions have no or only low homology with those of other Leishmania (Viannia) species, showing the divergence of those species within the subgenus.

Use of PCR in diagnosis of human american tegumentary leishmaniasis in Rio de Janeiro, Brazil.

In Brazil, the most common etiological agent of American tegumentary leishmaniasis is Leishmania (Viannia) braziliensis. In general, diagnostic techniques envisage the visualization of the parasite, but that technique has a low sensitivity. The main purpose of the present work was to evaluate the PCR as a routine tool for the diagnosis of leishmaniasis. Biopsy specimens from cutaneous or mucosal lesions were taken from 230 individuals from areas where Leishmania is endemic: 216 patients who had a clinical picture suggestive of leishmaniasis and 14 individuals with cutaneous lesions due to other causes. Each specimen was processed for histopathologic examination, culture, touch preparation, and DNA isolation. Oligonucleotides that amplify the conserved region of the minicircle molecules of Leishmania were used in a hot-start PCR. While at least one conventional technique was positive for Leishmania for 62% (134 of 216) of the patients, PCR coupled to hybridization was positive for 94% (203 of 216) of the patients. The 14 patients whose clinical picture was not suggestive of leishmaniasis had negative results by all techniques. The impact of the PCR was striking in mucosal disease. While the disease in only 17% (4 of 24) of the patients could be diagnosed by conventional techniques, PCR was positive for 71% (17 of 24) of the patients. Hybridization showed that all cases of disease were caused by parasites belonging to the Viannia subgenus. Altogether, the results indicate that PCR is a valuable tool for the diagnosis of leishmaniasis on a routine basis and is likely to provide valuable epidemiological information about the disease in countries where it is endemic.

Genetic data showing evolutionary links between Leishmania and Endotrypanum.

Striking similarities at the morphological, molecular and biological levels exist between many trypanosomatids isolated from sylvatic insects and/or vertebrate reservoir hosts that make the identification of medically important parasites demanding. Some molecular data have pointed to the relationship between some Leishmania species and Endotrypanum, which has an important epidemiological significance and can be helpful to understand the evolution of those parasites. In this study, we have demonstrated a close genetic relationship between Endotrypanum and two new leishmanial species, L. (V.) colombiensis and L. (V.) equatorensis. We have used (a) numerical zymotaxonomy and (b) the variability of the internal transcribed spacers of the rRNA genes to examine relationships in this group. The evolutionary trees obtained revealed high genetic similarity between L. (V.) colombiensis, L. (V.) equatorensis and Endotrypanum, forming a tight cluster of parasites. Based on further results of (c) minicircle kDNA heterogeneity analysis and (d) measurement of the sialidase activity these parasites were also grouped together.