Inactivation of the spxA1 or spxA2 gene of Streptococcus mutans decreases virulence in the rat caries model.

In oral biofilms, the major environmental challenges encountered by Streptococcus mutans are acid and oxidative stresses. Previously, we showed that the transcriptional regulators SpxA1 and SpxA2 are involved in general stress survival of S. mutans with SpxA1 playing a primary role in activation of antioxidant and detoxification strategies whereas SpxA2 serves as a back up activator of oxidative stress genes. We have also found that spxA1 mutant strains (∆spxA1 and ∆spxA1∆spxA2) are outcompeted by peroxigenic oral streptococci in vitro and have impaired abilities to colonize the teeth of rats fed a highly cariogenic diet. Here, we show that the Spx proteins can also exert regulatory roles in the expression of additional virulence attributes of S. mutans. Competence activation is significantly impaired in Δspx strains and the production of mutacin IV and V is virtually abolished in ΔspxA1 strains. Unexpectedly, the ∆spxA2 strain showed increased production of glucans from sucrose, without affecting the total amount of bacteria within biofilms when compared with the parent strain. By using the rat caries model, we showed that the capacity of the ΔspxA1 and ΔspxA2 strains to cause caries on smooth tooth surfaces is significantly impaired. The ∆spxA2 strain also formed fewer lesions on sulcal surfaces. This report reveals that global regulation via Spx contributes to the cariogenic potential of S. mutans and highlights that animal models are essential in the characterization of bacterial traits implicated in virulence.

Impairment of Interleukin-17A Expression in Canine Visceral Leishmaniosis is Correlated with Reduced Interferon-γ and Inducible Nitric Oxide Synthase Expression.

Dogs are the primary urban reservoir of Leishmania infantum and play a crucial role in the transmission of this parasite to man via sandflies. The spleen and liver are the main target organs of L. infantum infection, but few studies have evaluated the immune response to this infection in the canine liver. To identify the immunological mediators involved in resistance and/or susceptibility to canine visceral leishmaniosis (CVL), we selected 21 dogs naturally infected by L. infantum and classified as asymptomatic or symptomatic. Immunological parameters were analysed and correlations with clinical signs were determined. Symptomatic dogs showed higher numbers of parasites and less leucocyte infiltration in the liver compared with asymptomatic dogs. The progression of this disease was characterized not only by the down regulation of T helper (Th) 1-related cytokines, such as interferon (IFN)-γ and tumour necrosis factor (TNF)-α, but also by the down regulation of genes encoding interleukin (IL)-17A, inducible nitric oxide synthase (iNOS) and IL-10 in the spleen and liver in symptomatic dogs compared with asymptomatic dogs. Importantly, IL-17A gene transcription level was positively correlated with mRNA expression for iNOS and IFN-γ. Th1- and Th17-related cytokines therefore appear to play a role in restricting parasite growth via iNOS activation and decrease susceptibility of dogs to CVL.

Genetic analyses of Trypanosoma cruzi isolates from naturally infected triatomines and humans in northeastern Brazil.

Trypanosoma cruzi genetic diversity was investigated in 25 isolates (vectors and humans) from the semiarid zone of the State of Rio Grande do Norte, Brazil. Molecular markers (3' region of the 24Salpha rRNA; mitochondrial cytochrome oxidase subunit 2 (COII) gene; spliced leader intergenic region (SL-IR) gene; allelic size microsatellite polymorphism) identified 56% TcIII (100% Panstrongyluslutzi; 50% Triatomabrasiliensis); 40% TcII (91.7% humans; 50% T. brasiliensis) and 4% TcI (human). Microsatellite analysis revealed monoclonal and heterozygous patterns on one or more microsatellite loci in 64% of T. cruzi isolates (92.3% triatomines; 33.3% humans) and 36% putative polyclonal populations (66.7% humans; 7.7% triatomines) by loci SCLE10, SCLE11, TcTAT20, TcAAAT6, all belonging to TcII. Identical T. cruzi polyclonal profiles (88.9%) were detected, mostly from humans. The adaptative natural plasticity of TcII and TcIII and their potential for maintaining human infection in T. brasiliensis were confirmed. Intraspecific and phylogenetic T. cruzi diversity in the sylvatic and domestic transmission cycles in this specific region will provide exclusive control strategies.

Serological testing for celiac disease in women with endometriosis. A pilot study.

PURPOSE OF INVESTIGATION: Celiac disease (CD) involves immunologically mediated intestinal damage with consequent micronutrient malabsorption and varied clinical manifestations, and there is a controversial association with infertility. The objective of the present study was to determine the presence of CD in a population of infertile women with endometriosis. METHODS: A total of 120 women with a diagnosis of endometriosis confirmed by laparoscopy (study group) and 1,500 healthy female donors aged 18 to 45 years were tested for CD by the determination of IgA-transglutaminase antibody against human tissue transglutaminase (t-TGA) and anti-endomysium (anti-EMA) antibodies. RESULTS: Nine of the 120 women in the study group were anti-tTGA positive and five of them were also anti-EMA positive. Four of these five patients were submitted to intestinal biopsy which revealed CD in three cases (2.5% prevalence). The overall CD prevalence among the population control group was 1:136 women (0.66%). CONCLUSION: This is the first study reporting the prevalence of CD among women with endometriosis, showing that CD is common in this population group (2.5%) and may be clinically relevant.

Random amplified polymorphic DNA profiles of Trypanosoma cruzi isolates from chagasic patients with different clinical forms.

The genetic variability of 61 Trypanosoma cruzi isolates from 47 chronic chagasic patients of Minas Gerais state was analyzed by random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) using M13-40, lambdagt11-F, and L15996 primers. Cluster analysis by unweighted pair group method analysis was applied to RAPD profiles, and cluster analysis used to verify a possible correlation among different clinical forms of the disease from these patients. The T. cruzi isolates showed distinct grouping on tree topology, with the isolates not being possible to establish a correlation to the clinical forms of Chagas' disease. These data showed that the T. cruzi isolates from these patients would compose a group of populations well correlated genetically.

New cladoceran records from Lake Paranoá, Central Brazil.

The zooplanktonic community of Lake Paranoá has been studied for more than thirty years. Until 1998, when it was considered eutrophic, only three cladoceran species were known from the reservoir. Since 1999, when Lake Paranoá underwent intentional flushing, definite changes in species diversity and composition were identified. At the same time, exploratory studies on littoral cladoceran species were being done. The present study aims to provide additional information on the cladoceran species composition of Lake Paranoá. Seven new species records are presented, four of them also representing the first record from the Federal District (Brasília). The population previously considered as belonging to Bosmina longirostris was reconsidered and re-identified as Bosmina freyi. Figures and comments on species taxonomy and distribution are also provided.

New cladoceran records from Lake Paranoá, Central Brazil

A comunidade zooplanctônica do Lago Paranoá vem sendo objeto de estudo há mais de 30 anos. Até 1998, quando o reservatório era considerado eutrófico, apenas 3 espécies de cladóceros haviam sido registradas. Com a aceleração do processo de reoligotrofização, a comunidade planctônica apresentou pronunciadas modificações. Ao mesmo tempo, estudos exploratórios das espécies litorâneas de cladóceros foram desenvolvidos. O objetivo do presente trabalho é apresentar informações adicionais sobre a composição de cladóceros do Lago Paranoá. São apresentados sete novos registros de ocorrência, sendo quatro deles também o primeiro para o Distrito Federal. A espécie anteriormente identificada como Bosmina longirostris foi revista, o que acarretou sua reidentificação como Bosmina freyi. Ilustrações e comentários sobre a taxonomia e distribuição das oito espécies são apresentados.

New cladoceran records from Lake Paranoá, Central Brazil

The zooplanktonic community of Lake Paranoá has been studied for more than thirty years. Until 1998, when it was considered eutrophic, only three cladoceran species were known from the reservoir. Since 1999, when Lake Paranoá underwent intentional flushing, definite changes in species diversity and composition were identified. At the same time, exploratory studies on littoral cladoceran species were being done. The present study aims to provide additional information on the cladoceran species composition of Lake Paranoá. Seven new species records are presented, four of them also representing the first record from the Federal District (Brasília). The population previously considered as belonging to Bosmina longirostris was reconsidered and re-identified as Bosmina freyi. Figures and comments on species taxonomy and distribution are also provided.

A comunidade zooplanctônica do Lago Paranoá vem sendo objeto de estudo há mais de 30 anos. Até 1998, quando o reservatório era considerado eutrófico, apenas 3 espécies de cladóceros haviam sido registradas. Com a aceleração do processo de reoligotrofização, a comunidade planctônica apresentou pronunciadas modificações. Ao mesmo tempo, estudos exploratórios das espécies litorâneas de cladóceros foram desenvolvidos. O objetivo do presente trabalho é apresentar informações adicionais sobre a composição de cladóceros do Lago Paranoá. São apresentados sete novos registros de ocorrência, sendo quatro deles também o primeiro para o Distrito Federal. A espécie anteriormente identificada como Bosmina longirostris foi revista, o que acarretou sua reidentificação como Bosmina freyi. Ilustrações e comentários sobre a taxonomia e distribuição das oito espécies são apresentados.

Blood culture and polymerase chain reaction for the diagnosis of the chronic phase of human infection with Trypanosoma cruzi.

In the present study, we evaluated for the first time the profile of blood parasitism in untreated, chronic Chagas' disease. The study was conducted on 60 patients and a control group of nine serologically negative individuals. Analysis of three blood samples showed 70% cumulative positivity for blood culture and 86.7% positivity for PCR. The comparison of the two tests revealed that 41.1% (74/180) of the samples presented positive results for both PCR and blood culture, 22.2% (40/180) were positive for PCR alone, and 4.4% (8/180) were positive for blood culture and negative for PCR. The addition of the second sample raised positivity significantly for both blood culture ( P=0.0000) and PCR ( P=0.0369). Addition of the third sample was also statistically significant for blood culture ( P=0.0001) but not for PCR ( P=0.1186). These data point to the importance of studying the parasitemia of Trypanosoma cruzi-infected individuals before specific treatment. They also suggest that at least two blood samples should be collected and that two tests should be used, if possible--a procedure that considerably improves the parasitologic diagnosis of Chagas' disease and the evaluation of therapeutic efficacy.

Misoprostol use in obstetrics and gynecology in Brazil, Jamaica, and the United States.

OBJECTIVES: To investigate current clinical use of misoprostol for the treatment of a range of reproductive health indications by providers in Brazil, Jamaica, and the United States. METHODS: Using a 'snowball' sampling technique, we surveyed 228 gynecologists and obstetricians in Brazil (n=123), Jamaica (n=52), and the United States (n=53). RESULTS: Providers use misoprostol for labor induction (46%), postpartum hemorrhage (8%), intra-uterine fetal death (61%), cervical priming (21%), missed abortion (57%), and incomplete abortion (16%) as well as first and second trimester abortion induction (27% and 13%, respectively). CONCLUSIONS: There is considerable variation in the regimens used; moreover, the regimens commonly used in clinical practice often differ from those recommended in the medical literature. While misoprostol is an appealing alternative for many reproductive health indications in developing countries, the varied regimens and lack of registration raise critical medical and policy questions.

Cyclophosphamide-induced immunosuppression protects cardiac noradrenergic nerve terminals from damage by Trypanosoma cruzi infection in adult rats.

Trypanosoma cruzi-infected juvenile rats develop severe cardiac sympathetic denervation in parallel with acute myocarditis. This aspect has not been studied in adult rats, thought to be resistant to this infection. The mechanism involved in T. cruzi-induced neuronal damage remains to be completely elucidated. In juvenile rats, the mortality during the acute phase depends on T. cruzi populations, ranging from 30% to 100%. Therefore, studies of mechanisms through hazardous procedures such as immunosuppression are restricted. The current paper shows that adult rats infected with T. cruzi (Y strain) develop severe acute myocarditis and cardiac sympathetic denervation, despite null mortality and virtual absence of patent parasitaemia followed by negative haemoculture. Recovery from the myocarditis and denervation occurred but PCR studies showed persistence of parasite DNA at least until day 111 post inoculation. Immunosuppression by cyclophosphamide treatment increased the parasitaemia, prevented the acute myocarditis and the sympathetic denervation without significant alteration of the myocardial parasitism. These results argue against a direct role for parasite-derived products and implicate the inflammatory cells in the denervation process. As previous studies in juvenile animals have discarded an essential role for radiosensitive cells, the macrophages remain as the possible effectors for the T. cruzi-induced neuronal damage.

[Survival and infectious processes in pacients with AIDS: analysis based on initial serum vitamin A levels]. / Sobrevida e processos infecciosos em pacientes com AIDS: análise de acordo com os níveis séricos iniciais de vitamina A.

Patients with Aids (n = 39) were followed up for a maximum period of 36 weeks, after which the types and topographies of infectious complications presented and patient survival were analyzed and correlated with the vitamin A levels presented by the patients at the beginning of clinical follow-up. Twenty-one (53,8%) patients presented serum retinol levels below 1.6 micromol/L, 12 (57%) of whom had values lower than 1.05 micromol/L. There was no correlation between low serum vitamin A levels and the types or topographies of the infectious complications that occurred during the follow-up period. Although mean survival at the end of the 36 months follow-up period was similar for the two groups, patients with retinol deficiency presented a lower probability of survival during the first 24 months of follow-up compared to patients without hypovitaminosis A (8.44 x 1.42 months; p = 0.003).

Prevalence of antibodies to hepatitis B core antigen in blood donors in the middle West region of Brazil.

The prevalence of antibodies to hepatitis B core antigen in 552 prime blood donors was of 9.4%. The majority (71.2%) has antibodies to hepatitis B surface antigen. The hepatitis B surface antigen was present in 0.7%, all of them antibodies to hepatitis B core antigen positive.

Human leukocyte antigen class II alleles in white Brazilian patients with celiac disease.

BACKGROUND: Celiac disease (CD) is a permanent gluten intolerance disorder characterized by malabsorption, intestinal mucosa villus atrophy, and crypt hyperplasia. Clinical and histologic features improve in persons consuming a gluten free diet. The pathogenesis of CD involves environmental, genetic, and immunologic factors. METHODS: The frequencies of human leukocyte antigen (HLA) class II alleles were evaluated in white Brazilian patients who had CD and compared with those observed in healthy individuals from the same geographical area (Ribeirão Preto, São Paulo) and of similar ethnic background. Twenty-five patients with CD, 11 females and 14 males, and 91 control individuals were studied. The HLA class II alleles were typed using amplified DNA hybridized with sequence-specific primers. Statistical analysis was performed using the two-tailed Fisher exact test. The relative risk (RR), etiologic fraction (EF), and preventive fraction (PF) were also estimated. The EF represents the attributable risk for the development of CD at the population level, whereas PF represents the protective risk. RESULTS: The frequency of the HLA-DRB1*03, HLA-DRB1*07, and HLA-DQB1*02 alleles was significantly increased in patients. The RR conferred by these alleles was 5.35, 7.15, and 10.6, respectively, and the EF was 48.7%, 44.7%, and 76%, respectively. The frequency of HLA-DQB1*06 alleles was significantly decreased in CD patients, conferring an RR of 0.08 and a PF of 48%. CONCLUSIONS: The results show that HLA-DRB1*03, HLA-DRB1*07, and HLA-DQB1*02 alleles conferred susceptibility to CD in Brazilian patients. In contrast, HLADQB1*06 alleles conferred protection against development of the disease.

Therapeutic trial in experimental tegumentary leishmaniasis caused by Leishmania (Leishmania) amazonensis. A comparative study between mefloquine and aminosidine.

One hundred and eighty-two male inbred C57/BL/6 mice were infected with 3 x 10(6) Leishmania (Leishmania) amazonensis promastigotes of the MHOM/BR/PH8 strain by means of a subcutaneous injection in the right ear. The animals were separated in three groups: 1) oral mefloquine hydrochloride treatment (16 mg/kg/day/10 days), 2) intramuscular aminosidine (Paromomycin) treatment (20 mg/kg/20 days) and 3) control. Twenty-six mice of each treated group were sacrificed, one at the end of treatment (nine weeks after inoculation), and one six weeks later (fifteen weeks after inoculation). Control Group animals were sacrificed at weeks six, nine and fifteen after inoculation. There was no significant difference between Group 1 (mefloquine) and Group 3 (control) subjects. Group 2 animals (aminosidine) presented the smallest differences of all, both at the end of the treatment and six weeks later. The histopato-logical parameters have shown the following findings: a) there was no significant difference between the mefloquine treated group and the control group; the group treated with aminosidine showed fewer of vacuolated macrophages than the control group, at week 9 (end of treatment). b) both at the end of treatment and six weeks later, evaluation of tissue necrosis and tissue fibrosis revealed no differences between the treated groups. It was found that six weeks after the end of treatment, mice in the control group presented significantly more severe degrees of fibrosis than mice in the other groups. It can be concluded that mefloquine showed limited therapeutic effect in this experimental model, whereas aminosidine had a significant effect. Nevertheless, neither of them resulted in cure of the lesions.

Relation of the disaccharidases in the small intestine of the rat to the degree of experimentally induced iron-deficiency anemia

Hypolactasia associated with severe iron-deficiency anemia has been reported in several studies. The objective of the present study was to determine whether hypolactasia is associated with the degree and duration of iron-deficiency anemia. Newly weaned male Wistar rats were divided into a control group receiving a diet supplemented with iron (C) and an experimental group (E) receiving a diet not supplemented with iron (iron-deficiency diet). The animals were studied on the 3rd, 5th, 7th, 14th, 21st, 28th and 35th days of the experiment, when overall and iron nutritional status and disaccharidase activity in the small intestine were determined by the Dahlqvist method. A reduction in weight occurred in the anemic animals starting on the 5th day of the study. Anemia was present in the experimental animals, with a progressive worsening up to the 14th day (hemoglobin: C = 13.27 and E = 5.37) and stabilizing thereafter. Saccharase and maltase activities did not differ significantly between groups, whereas lactase showed a significant reduction in total (TA) and specific activity (SA) in the anemic animals starting on the 21st day of the study. Median lactase TA for the C and E groups was 2.27 and 1.25 U on the 21st day, 2.87 and 1.88 U on the 28th day, and 4.20 and 1.59 U on the 35th day, respectively. Median lactase SA was 0.31 and 0.20 U/g wet weight on the 21st day, 0.39 and 0.24 U/g wet weight on the 28th day, and 0.42 and 0.23 U/g wet weight on the 35th day, respectively. These findings suggest a relationship between the enzymatic alterations observed and both the degree and duration of the anemic process. Analysis of other studies on intestinal disaccharidases in anemia suggests that the mechanism of these changes may be functional, i.e., that the enterocytes may suffer a reduction in their ability to synthesize these enzymes.

Relation of the disaccharidases in the small intestine of the rat to the degree of experimentally induced iron-deficiency anemia.

Hypolactasia associated with severe iron-deficiency anemia has been reported in several studies. The objective of the present study was to determine whether hypolactasia is associated with the degree and duration of iron-deficiency anemia. Newly weaned male Wistar rats were divided into a control group receiving a diet supplemented with iron (C) and an experimental group (E) receiving a diet not supplemented with iron (iron-deficiency diet). The animals were studied on the 3rd, 5th, 7th, 14th, 21st, 28th and 35th days of the experiment, when overall and iron nutritional status and disaccharidase activity in the small intestine were determined by the Dahlqvist method. A reduction in weight occurred in the anemic animals starting on the 5th day of the study. Anemia was present in the experimental animals, with a progressive worsening up to the 14th day (hemoglobin: C = 13.27 and E = 5.37) and stabilizing thereafter. Saccharase and maltase activities did not differ significantly between groups, whereas lactase showed a significant reduction in total (TA) and specific activity (SA) in the anemic animals starting on the 21st day of the study. Median lactase TA for the C and E groups was 2.27 and 1.25 U on the 21st day, 2.87 and 1. 88 U on the 28th day, and 4.20 and 1.59 U on the 35th day, respectively. Median lactase SA was 0.31 and 0.20 U/g wet weight on the 21st day, 0.39 and 0.24 U/g wet weight on the 28th day, and 0.42 and 0.23 U/g wet weight on the 35th day, respectively. These findings suggest a relationship between the enzymatic alterations observed and both the degree and duration of the anemic process. Analysis of other studies on intestinal disaccharidases in anemia suggests that the mechanism of these changes may be functional, i.e., that the enterocytes may suffer a reduction in their ability to synthesize these enzymes.

[Study of lung involvement in patients with cystic fibrosis] / Estudo do quadro pulmonar de pacientes com fibrose cística.

OBJECTIVE: To characterize the involvement of the respiratory apparatus of patients with cystic fibrosis in order to obtain a comprehensive view of their pulmonary picture.METHODS: Data were obtained retrospectively from the medical records of 16 patients with cystic fibrosis; arterial gas and spirometry data were obtained prospectively for the same patients, who were not in an acute pulmonary situation. The patients were subjects of both sexes aged 6 years or older who were followed up at the Pediatrics Outpatient Clinic of the University Hospital, Faculty of Medicine of Ribeirão Preto, USP.RESULTS: Median patient age was 114 months (9 years and 6 months) ranging between 72 - 360 months, and 68.75% were males. Productive cough was the most frequent symptom observed in 75% of the population studied. All patients had positive sputum culture obtained at least one year before, with Pseudomonas aeruginosa being detected in 81.25% of the cases. Arterial gases revealed some abnormalities in 81.25% of the patients and spirometry revealed abnormalities in 56.25%.CONCLUSION: All patients presented at least one type of pulmonary alteration. Measurement of arterial gases detected a larger number of patients with altered pulmonary function than did spirometry, but the two examinations complemented each other for a good evaluation of pulmonary function.

Postmortem tooth loss in human identification processes.

Teeth provide essential data for human identification. However, they are frequently lost during the process of skeletonization or under manipulation during exhumation. Because of the high frequency of postmortem tooth loss, this phenomenon was examined in three different samples, in an attempt to simulate the actual circumstances experienced in the forensic processes of identification of human remains. The method employed aimed to describe and quantify dental spaces, distinguishing between loss after death or before by extraction. The results showed a high prevalence of postmortem tooth loss: 41.37% in sample A, 56.83% in sample B and 3.96% in sample C. These losses were most frequent in the maxillary incisor group in all three samples analysed. These data underline the need for redoubled care in recovery, transportation and storage of crania, so that teeth are not lost, which could seriously compromise the identification process.