Molecular characterization of Blastocystis subtypes isolated in the city of Uberaba, Minas Gerais State, Brazil.

INTRODUCTION: Blastocystis is an intestinal protozoan that may play a role in the pathogenicity of humans. This study aimed to (i) genetically characterize Blastocystis isolates obtained from human fecal samples and the water supply of the city of Uberaba, Minas Gerais, Brazil, and (ii) to verify the phylogenetic relationship between these isolates. METHODS: Blastocystis species present in 26 fecal samples obtained from humans and animals from Uberaba were genetically characterized by polymerase chain reaction-restriction fragment length polymorphism and polymerase chain reaction-sequence-tagged sites. All amplicons were partially sequenced and/or defined according to the GenBank classification. RESULTS: Polymerase chain reaction amplicons were generated from 21 human isolates and 18 water samples. The subtypes defined were ST1 (53.3%), ST3 (40.0%), and ST2 (6.7%) for human isolates; ST10 (100%) for bovine isolates; and ST5 (50.0%), ST1 (25%), and ST3 (25%) for pigs. Sequencing of polymerase chain reaction products showed a 98%-99% identity for the Blastocystis sequences deposited in GenBank, except for sequences from water samples that showed the identity of algae sequences. Phylogenetic analysis of Blastocystis sequences showed two distinct groups, one of which was principally formed by ST1, ST5, and ST10, and the other by isolates characterized as ST3 and ST7. Both clades showed human and animal sequences, reinforcing the notion that Blastocystis subtypes are not host-specific. CONCLUSIONS: The data showed that Blastocystis subtypes circulating in Uberaba are ST1-ST3, ST5, and ST10, present in both humans and animals, demonstrating that the Blastocystis subtypes are not host-specific; that is, zoonotic transmission is possible.

Biomarkers assessment in patients with Chagas disease and systemic arterial hypertension.

Chagas disease (ChD) and systemic arterial hypertension (SAH) are two severe comorbidities that lead to mortality and a reduction in people's quality of life, with an impact on public health. The aim of this study was to quantify the biomarkers of cardiac injury in patients with ChD and SAH. Eighty patients were divided into four groups: 20 hypertensive patients, 20 ChD-hypertensive patients, 20 ChD patients, and 20 normotensive volunteers; all of them came from outpatient's public health services. Among the evaluated markers for cardiac lesions (creatine kinase, creatine kinase-MB isoform, myoglobin, high-sensitive cardiac troponin T[hs-cTnT], B-type natriuretic peptide [BNP], and C-reactive protein), hs-cTnT and BNP were the most appropriate. Importantly, our results showed that the cut off point for hs-cTnT could be < 0.007 ng/mL, which could lead to the early detection of myocardial lesions. The BNP and hs-cTnT levels were high only in the ChD and ChD-hypertensive patient groups, suggesting that Chagas' disease may play an important role in the increase of these biomarkers. ChD patients, hypertensive or not, with cardiac or cardiodigestive involvement presented significantly higher values of hs-cTnT (p < 0.001) and BNP (p = 0.001) than ChD patients with indeterminate and digestive forms, which strengthens the validation of these markers for the follow-up of clinical cardiac form of ChD. This study suggests that the BNP and hs-cTnT can be used as possible indirect biomarkers of cardiac damage. In addition, the reference values of these biomarkers in Chagas and hypertensive cardiomyopathies should be better understood with further studies.

Evaluation of Different Oocyst DNA Extraction Methods for Cryptosporidium spp. Research in Environmental Samples.

PURPOSE: The major problem of the PCR method for the search of protozoan cysts/oocysts in environmental samples is the presence of inhibitors. DNA extraction methods capable of removing inhibitory substances of environmental origin and recovering the DNA are decisive for the efficiency of PCR. This study aimed to compare the efficiency of different DNA extraction methods for the search by Cryptosporidium oocysts in water samples by molecular methods. METHODS: DNA extraction from water samples was performed using four different methods. Two methods use a chaotropic buffer to extract DNA and promote the selective binding of DNA to a silica membrane (GuSCN-silica and GFX Kit). The other method is based on the lysis and digestion of the samples in buffer and proteinase K, adsorption of impurities by an "InhibitEX" insertion matrix and purification of the DNA by a silica column (QIAamp Kit). The fourth method uses ionic and non-ionic detergents and proteinase K, to solubilize and separate the DNA from proteins, and a paramagnetic resin for DNA purification in the presence of high concentrations of guanidine ions (MAGNEX DNA Kit). Nested-PCR was performed, and the Cryptosporidium SSU rDNA gene amplified. RESULTS: The results demonstrated that MAGNEX and GFX commercial kits showed higher sensitivity, with detection of up to 100 oocysts/mL and 104 oocysts/mL respectively. CONCLUSION: In conclusion, this study confirmed that for low-DNA environmental samples, extraction methods should include an efficient oocyst wall breaking step, and showed that the best Cryptosporidium DNA extraction methods are those that use paramagnetic resins.

Occurrence of Blastocystis spp. in domestic animals in Triângulo Mineiro area of Brazil.

INTRODUCTION: Currently, there are few studies regarding Blastocystis epidemiology. This study aimed to evaluate the occurrence of Blastocystis in animals in Uberaba, Brazil. METHODS: Fecal samples were examined by parasitological methods and screened for Blastocystis by polymerase chain reaction. RESULTS: Blastocystis spp. were observed in pigs, sheep, cattle, and dogs. Blastocystis polymerase chain reaction was positive in 14/22 samples positive by parasitological methods. CONCLUSIONS: The occurrence of Blastocystis in animals is high, with a predominance of subtype 1 in the region. This is the first study conducted in Brazil showing the genetic profile of Blastocystis isolated from animals.

Occurrence of Blastocystis spp. in domestic animals in Triângulo Mineiro area of Brazil

Abstract INTRODUCTION: Currently, there are few studies regarding Blastocystis epidemiology. This study aimed to evaluate the occurrence of Blastocystis in animals in Uberaba, Brazil. METHODS: Fecal samples were examined by parasitological methods and screened for Blastocystis by polymerase chain reaction. RESULTS: Blastocystis spp. were observed in pigs, sheep, cattle, and dogs. Blastocystis polymerase chain reaction was positive in 14/22 samples positive by parasitological methods. CONCLUSIONS: The occurrence of Blastocystis in animals is high, with a predominance of subtype 1 in the region. This is the first study conducted in Brazil showing the genetic profile of Blastocystis isolated from animals.

Semisolid liver infusion tryptose supplemented with human urine allows growth and isolation of Trypanosoma cruzi and Trypanosoma rangeli clonal lineages.

INTRODUCTION: This work shows that 3% (v/v) human urine (HU) in semisolid Liver Infusion Tryptose (SSL) medium favors the growth of Trypanosoma cruzi and T. rangeli. METHODS: Parasites were plated as individual or mixed strains on SSL medium and on SSL medium with 3% human urine (SSL-HU). Isolate DNA was analyzed using polymerase chain reaction (PCR) and pulsed-field gel electrophoresis (PFGE). RESULTS: SSL-HU medium improved clone isolation. PCR revealed that T. cruzi strains predominate on mixed-strain plates. PFGE confirmed that isolated parasites share the same molecular karyotype as parental cell lines. CONCLUSIONS: SSL-HU medium constitutes a novel tool for obtaining T. cruzi and T. rangeli clonal lineages.

OCCURRENCE OF Blastocystis spp. IN UBERABA, MINAS GERAIS, BRAZIL.

Intestinal parasites are a problem for public health all over the world. The infection with Blastocystis, a protozoan of controversial pathogenicity, is one of the most common among them all. In this study, the occurrence of intestinal parasites, with emphasis on Blastocystis, in patients at the Universidade Federal do Triângulo Mineiro was investigated in Uberaba (MG) through microscopy of direct smears and fecal concentrates using Ritchie's method. Feces of 1,323 patients were examined from April 2011 to May 2012. In 28.7% of them at least one intestinal parasite was identified, and the most frequent organisms were Blastocystis spp. (17.8%) and Giardia intestinalis (7.4%). The occurrence of parasitism was higher in children aged 6 -10 years old, and the infection with Blastocystis spp. was higher above the age of six (p < 0.001). The exclusive presence of G. intestinalis and of Blastocystis spp. was observed in 5.4% and 12.2% of the patients, respectively. Regarding patients with diarrheic feces, 8% revealed unique parasitism of Blastocystis spp. Other intestinal parasites observed in children were Ascaris lumbricoides (0.3%) and Entamoeba histolytica/dispar/moshkovskii (1.4%). The Ritchie's method was more sensitive (92.8%) when compared to direct microscopy (89.8%), with high agreement between them (97.7%, kappa = 0.92). In conclusion, the occurrence of Blastocystis spp. in Uberaba is high and the presence of diarrheic feces with exclusive presence of the parasite of Blastocystis spp. was observed.

OCCURRENCE OF Blastocystis spp. IN UBERABA, MINAS GERAIS, BRAZIL / Ocorrência de Blastocystis spp. em Uberaba, Minas Gerais, Brasil

Intestinal parasites are a problem for public health all over the world. The infection with Blastocystis, a protozoan of controversial pathogenicity, is one of the most common among them all. In this study, the occurrence of intestinal parasites, with emphasis on Blastocystis, in patients at the Universidade Federal do Triângulo Mineiro was investigated in Uberaba (MG) through microscopy of direct smears and fecal concentrates using Ritchie’s method. Feces of 1,323 patients were examined from April 2011 to May 2012. In 28.7% of them at least one intestinal parasite was identified, and the most frequent organisms were Blastocystis spp. (17.8%) and Giardia intestinalis (7.4%). The occurrence of parasitism was higher in children aged 6 -10 years old, and the infection with Blastocystis spp. was higher above the age of six (p < 0.001). The exclusive presence of G. intestinalis and of Blastocystis spp. was observed in 5.4% and 12.2% of the patients, respectively. Regarding patients with diarrheic feces, 8% revealed unique parasitism of Blastocystis spp. Other intestinal parasites observed in children were Ascaris lumbricoides (0.3%) and Entamoeba histolytica/dispar/moshkovskii (1.4%). The Ritchie’s method was more sensitive (92.8%) when compared to direct microscopy (89.8%), with high agreement between them (97.7%, kappa = 0.92). In conclusion, the occurrence of Blastocystis spp. in Uberaba is high and the presence of diarrheic feces with exclusive presence of the parasite of Blastocystis spp. was observed.

Parasitos intestinais são um problema de saúde pública no mundo e a infecção por Blastocystis, protozoário de patogenicidade controversa, é uma das mais frequentes. Nesse estudo foi investigada a ocorrência de parasitos intestinais em pacientes atendidos na Universidade Federal do Triângulo Mineiro, em Uberaba (MG), com ênfase em Blastocystis, pelos métodos parasitológicos direto e de Ritchie. Foram examinadas fezes de 1.323 pacientes de abril/2011 a maio/2012. Em 28,7% deles foi identificado um parasito intestinal, sendo Blastocystis spp. (17,8%) e Giardia intestinalis (7,4%) os mais frequentes. A ocorrência de parasitismo foi maior em crianças de 6-10 anos e a infecção por Blastocystis spp. foi maior acima de seis anos (p < 0,001). Presença exclusiva de G. intestinalis e de Blastocystis spp. foi observada em 5,4% e 12,2% dos pacientes, respectivamente, sendo que dos pacientes com fezes diarreicas, 8% apresentavam parasitismo exclusivo por Blastocystis spp. Outros parasitos intestinais observados em crianças foram Ascaris lumbricoides (0,3%) e Entamoeba histolytica/dispar/moshkovskii (1,4%). O método de Ritchie foi mais sensível (92,8%) que o direto (89,8%), com alta concordância entre eles (97,7%, kappa = 0,92). Em conclusão, a ocorrência de Blastocystis spp. em Uberaba é elevada e foi observada a presença de fezes diarreicas com parasitismo exclusivo por Blastocystis spp.

Ultrastructural aspects of Cystoisospora belli (syn. Isospora belli) in continuous cell lines.

Cystoisospora belli is an opportunistic protozoan that causes human cystoisosporiasis, an infection characterized by diarrhea, steatorrhea, abdominal pain, fever, and weight loss. The lack of animal models susceptible to C. belli, and the difficulty in obtaining clinical samples with fair amounts of oocysts have limited the research pertaining to the basic biology of this parasite. This study aimed to describe the ultrastructure of endogenous stages of C. belli in Monkey Rhesus Kidney Cells (MK2) and Human Ileocecal Adenocarcinoma cells (HCT-8). Zoites of C. belli exhibited typical morphological features of coccidia, which included a trilaminar pellicle, an apical complex formed by a conoid, polar rings, rhoptries, and micronemes, in addition to dense granules and the endoplasmic reticulum. No crystalloid body was observed but various lipid and amylopectin granules were usually present in the cytoplasm of zoites. We observed a tendency of the endoplasmic reticulum of the host cell to be located near the parasitophorous vacuole membrane. Merozoites were formed by endodyogeny and during replication, the apical complex of the mother cell remained intact. The formation of gametes or oocysts was not observed. The ultrastructural findings of C. belli are further evidence of its proximity to Sarcocystidae family members and corroborate their reclassification as Cystoisospora spp.

Prevalence and genetic characterization of Cryptosporidium spp. and Cystoisospora belli in HIV-infected patients.

Cryptosporidium spp. and Cystoisospora belli are monoxenic protozoa that have been recognized as the causative agents of chronic diarrhea in immunocompromised individuals, especially HIV-infected subjects. The objective of this study was to evaluate the frequency of these intestinal protozoa in HIV-positive patients in the Triângulo Mineiro region of Brazil and to correlate the presence of these infections with clinical, epidemiological and laboratory data of the patients. Oocysts were detected in stool samples of 10 (16.9%) of the 59 patients studied, while Cryptosporidium spp. were present in 10.1% (6/59) and C. belli in 6.7% (4/59). The frequency of these parasites was higher among patients with diarrheic syndrome and CD4+ T lymphocyte counts < 200 cells/mm 3 , demonstrating the opportunistic characteristic of these infections. A significant association was observed between the lack of adherence to antiretroviral therapy and the presence of Cryptosporidium spp. and/or C. belli. Parasitism with Cryptosporidium spp. was more frequent in February and April, the months following the period of high rainfall. The same was not observed for C. belli. Genetic characterization of two isolates led to the identification of Cryptosporidium parvum, one of the main species associated with the zoonotic transmission of cryptosporidiosis.

Prevalence and genetic characterization of Cryptosporidium spp. and Cystoisospora belli in HIV-infected patients / Prevalência e caracterização genética de Cryptosporidium spp. e Cystoisospora belli em pacientes infectados pelo HIV

Cryptosporidium spp. and Cystoisospora belli are monoxenic protozoa that have been recognized as the causative agents of chronic diarrhea in immunocompromised individuals, especially HIV-infected subjects. The objective of this study was to evaluate the frequency of these intestinal protozoa in HIV-positive patients in the Triângulo Mineiro region of Brazil and to correlate the presence of these infections with clinical, epidemiological and laboratory data of the patients. Oocysts were detected in stool samples of 10 (16.9%) of the 59 patients studied, while Cryptosporidium spp. were present in 10.1% (6/59) and C. belli in 6.7% (4/59). The frequency of these parasites was higher among patients with diarrheic syndrome and CD4+ T lymphocyte counts < 200 cells/mm 3 , demonstrating the opportunistic characteristic of these infections. A significant association was observed between the lack of adherence to antiretroviral therapy and the presence of Cryptosporidium spp. and/or C. belli. Parasitism with Cryptosporidium spp. was more frequent in February and April, the months following the period of high rainfall. The same was not observed for C. belli. Genetic characterization of two isolates led to the identification of Cryptosporidium parvum, one of the main species associated with the zoonotic transmission of cryptosporidiosis.

Cryptosporidium spp. e Cystoisospora belli são protozoários monoxenos reconhecidos como agentes causadores de diarréia crônica em indivíduos imunocomprometidos, especialmente aqueles infectados pelo HIV. Os objetivos deste estudo foram o de avaliar a frequência destes protozoários em pacientes HIV - positivos na região do Triângulo Mineiro, Brasil, e correlacionar a presença destas infecções com dados clínicos, epidemiológicos e laboratoriais dos pacientes. Oocistos foram detectados em amostras fecais de 10 (16,9%) dos 59 pacientes estudados, sendo 10.1% (6/59) das amostras positivas para Cryptosporidium spp. e 6,7% (4/59) das amostras positivas para C. belli. A frequência destes parasitos foi maior entre pacientes com síndrome diarreica e contagem de linfócitos T CD4+ < 200 cells/mm 3 , o que demonstra o caráter oportunista destas infecções. Foi observada uma associação significativa entre a falta de aderência à terapia antiretroviral e a presença de Cryptosporidium spp. e/ou C. belli. Parasitismo por Cryptosporidium spp. foi mais frequente em fevereiro e abril, meses subsequentes ao período chuvoso. O mesmo não foi observado para C. belli. A caracterização genética de dois isolados levou à identificação de Cryptosporidium parvum, uma das principais espécies associadas com a transmissão zoonótica da criptosporidiose.

Sequencing and analysis of chromosomal extremities of Trypanosoma rangeli in comparison with Trypanosoma cruzi lineages.

The aim of this study was to investigate the genetic variability of sequences present in the chromosome ends of Trypanosoma rangeli strains defined by the presence (+) or absence (-) of KP1 minicircles, and to compare the mean terminal restriction fragment (TRF) lengths to those of Trypanosoma cruzi populations representative of groups TcI, TcII, TcIV, and TcVI. Southern blots containing RsaI-digested genomic DNA of T. rangeli KP1(+) strains, T. rangeli KP1(-) strains, and T. cruzi strains were probed with the previously described subtelomeric sequences (170 bp) of T. rangeli and with telomeric hexamer repeats. Mean TRF length analysis showed that the chromosome ends of T. rangeli are distinctly organized, with TRFs ranging from 1.3 to 9 kb for KP1(+) strains and from 0.3 to 5.0 kb for KP1(-) strains. In T. cruzi, TRF length ranged from 0.2 to 9 kb and no association with the genotype of the parasite could be established. Sequence analysis of the 170-bp amplicons revealed the occurrence of sequence polymorphisms in the subtelomeric region between and within KP1(+) and KP1(-) strains. The GTT triplet was detected in all KP1(+) strains, except for strain Cas4, but not in any of the KP1(-) strains. The dendrogram constructed by alignment of all T. rangeli strains showed the division into two main groups, mainly related to the presence or absence of the KP1 minicircle. In conclusion, the present results extend the genotype differences demonstrated by kDNA and karyotype analysis in T. rangeli to the chromosome ends of the parasite.

Polymorphisms in the 18S rDNA gene of Cystoisospora belli and clinical features of cystoisosporosis in HIV-infected patients.

Intraspecific variability among Cystoisospora belli isolates and its clinical implications in human cystoisosporosis have not been established. In this study, the restriction fragment length polymorphisms in a 1.8-kb amplicon of the small subunit ribosomal DNA (SSU rDNA) of the parasite was investigated in 20 C. belli-positive stool samples obtained from 15 HIV-infected patients. Diarrheic syndrome was observed in all patients with cystoisosporosis and the number of diarrheic episodes per patient during hospitalization ranged from 1 to 26 (mean of 9.64 ± 9.30), with a mean duration of 2 to 12 days (mean of 5.90 ± 3 days). Three restriction profiles (RF) were generated with MboII digestion, which were named RFI, RFII, and RFIII. Two isolates obtained from a patient with extraintestinal cystoisosporosis showed distinct restriction profiles with MboII. This study demonstrates that patients can be infected with different C. belli genotypes, and this information may be useful for identifying new C. belli genotypes infecting humans.

Karyotype variability in KP1(+) and KP1(-) strains of Trypanosoma rangeli isolated in Brazil and Colombia.

In the present study, the molecular karyotypes of 12 KP1(+) and KP1(-) Trypanosoma rangeli strains were determined and 10 different molecular markers were hybridized to the chromosomes of the parasite, including seven obtained from T. rangeli [ubiquitin hydrolase (UH), a predicted serine/threonine protein kinase (STK), hexose transporter, hypothetical protein, three anonymous sequences] and three from Trypanosoma cruzi [ubiquitin-conjugating enzyme E2 (UBE2), ribosomal RNA methyltransferase (rRNAmtr), proteasome non-ATPase regulatory subunit 6 (PSMD6)]. Despite intraspecific variation, analysis of the karyotype profiles permitted the division of the T. rangeli strains into two groups coinciding with the KP1(+) and KP1(-) genotypes. Southern blot hybridization showed that, except for the hexose transporter probe, all other probes produced distinct patterns able to differentiate the KP1(+) and KP1(-) genotypes. The UH, STK and An-1A04 probes exclusively hybridized to the chromosomes of KP1(+) strains and can be used as markers of this group. In addition, the UBE2, rRNAmtr and PSMD6 markers, which are present in a conserved region in all trypanosomatid species sequenced so far, co-hybridized to the same T. rangeli chromosomal bands, suggesting the occurrence of gene synteny in these species. The finding of distinct molecular karyotypes in KP1(+) and KP1(-) strains of T. rangeli is noteworthy and might be used as a new approach to the study of genetic variability in this parasite. Together with the Southern blot hybridization results, these findings demonstrate that differences at the kDNA level might be associated with variations in nuclear DNA.

Interstitial cells of Cajal in chagasic megaesophagus.

Chagasic visceromegalies are the most important digestive manifestations of Chagas disease and are characterized by motor disorders and dilation of organs such as esophagus and colon. One of the theories raised to explain the physiopathogenesis of chagasic megas is the plexus theory. Recent studies have shown a reduction of interstitial cells of Cajal (ICCs) in the colon of chagasic patients. These cells are present throughout the gastrointestinal tract and are considered to be pacemaker cells, that is, they are responsible for coordinating peristalsis and for mediating nerve impulses. In view of the lack of studies on these cells in megaesophagus and the previous observation of a reduction of ICCs in chagasic megacolons, we compared the distribution of ICCs in the esophagus of chagasic and nonchagasic patients to contribute to a better understanding of the physiopathogenesis of this esophageal disease. Esophageal biopsy samples from 10 chagasic and 5 nonchagasic patients were used. Cells were identified with the anti-CD117 antibody. The number of ICCs was quantified in longitudinal and circular muscle layers and myenteric plexus. The results were analyzed statistically by comparison of means. An intense reduction in the number of ICCs was observed in muscle layers and in the myenteric plexus of patients with megaesophagus. We conclude that there is an intense reduction of ICCs in the esophagus of chagasic patients when compared to nonchagasic patients, a finding supporting the important role of these cells in gastrointestinal tract motility. A deficiency in these cells might be implied in the genesis of megaesophagus.

Susceptibility of different triatomine species to Trypanosoma rangeli experimental infection.

Trypanosoma rangeli is a kinetoplastid protozoan parasite that has been found in the majority of Latin American countries, overlapping its distribution area with that of Trypanosoma cruzi, the causative agent of Chagas disease. This parasite shares the same reservoirs and vectors as T. cruzi. Triatomines from genus Rhodnius are considered the most susceptible hosts to infection. In this work, we report the susceptibility of different triatomine species (Rhodnius neglectus, Panstrongylus megistus, Triatoma infestans, T. sordida, T. braziliensis, and T. vitticeps) to experimental infection by T. rangeli isolated from Didelphis albiventris in a highly endemic region for Chagas disease. An intense parasitism was evidenced in feces (56% to 81%) of the majority of the species studied on the 10th day after infection, decreasing during the period of the experiment (30 days). T. vitticeps did not present parasites in feces at any time. All triatomine species presented parasites in the hemolymph. In T. vitticeps and P. megistus, this parasitism was scarce (6.3% and 6.6%, respectively). In the other species, the parasitism was variable (62.5% to 100%). Triatomine mortality varied between 3% to 40%, increasing during the infection in all species studied. The lowest mortality was observed for T. infestans. Also, we showed that only trypomastigotes forms from salivary glands, and hemolymph were infective for mice. We conclude that all triatomine species used were susceptible to infection by T. rangeli at different levels. There was no direct correlation between intensity of parasitism and mortality.

Functional and histopathological study of the pancreas in hamsters (Mesocricetus auratus) infected and reinfected with Trypanosoma cruzi.

Histopathological and functional changes in the pancreas were studied in 94 hamsters infected and reinfected with Trypanosoma cruzi VIC strain and in 73 non-infected normal controls. Infection in each animal was verified by microhematocrit, hemoculture, specific peroxidase anti-peroxidase, polymerase chain reaction and seroagglutination. Blood glucose and insulin were determined. The number of islets per section and the number of islet cells marked with antibodies were counted. Insulitis, neuritis, fibrosis, atrophy and inflammatory infiltrates were evaluated. Experimental chagasic infection caused pancreatitis similar to human Chagas' disease, involving acini, islets and nerves, with atrophy and fibrosis, although without correlation to the number of reinfections. Erratic blood glucose levels and a tendency to hypoinsulinemia were observed in infected animals. During the acute phase, the number of somatostatin and pancreatic polipeptide producer islet cells was lower in infected hamsters, which was eventually related to changes in blood sugar levels and hypoinsulinemia. Our findings favor the hypothesis of the existence of an endocrine form of chronic chagasic infection.

Genitourinary changes in hamsters infected and reinfected with Trypanosoma cruzi.

Authors describe genitourinary changes in male hamsters infected and reinfected with Trypanosoma cruzi. Changes in genital organs have been described in human and in experimental chagasic infection. Genital dysfunctions in chronic chagasic patients affect ejaculation, libido and sexual potency, and testis biopsies may show arrested maturation of germ cells, oligozoospermia and azoospermia. Sixty-five male hamsters were inoculated and reinoculated with 2x10 trypomastigotes of T. cruzi VIC strain, and 22 non-infected animals constituted the control group. Animals were necropsied and fragments from testis, epididymis, seminal vesicle and bladder were collected and stained with hematoxylin-eosin. Peroxidase anti-peroxidase procedure was utilized to detect tissue parasitism. T. cruzi nests were found in testis, epididymis and seminal vesicle of these hamsters. Such parasitism plays a role in the origin of genital lesions observed in humans and laboratory animals during chronic chagasic infection.

Genitourinary changes in hamsters infected and reinfected with Trypanosoma cruzi

Authors describe genitourinary changes in male hamsters infected and reinfected with Trypanosoma cruzi. Changes in genital organs have been described in human and in experimental chagasic infection. Genital dysfunctions in chronic chagasic patients affect ejaculation, libido and sexual potency, and testis biopsies may show arrested maturation of germ cells, oligozoospermia and azoospermia. Sixty-five male hamsters were inoculated and reinoculated with 2x10 trypomastigotes of T. cruzi VIC strain, and 22 non-infected animals constituted the control group. Animals were necropsied and fragments from testis, epididymis, seminal vesicle and bladder were collected and stained with hematoxylin-eosin. Peroxidase anti-peroxidase procedure was utilized to detect tissue parasitism. T. cruzi nests were found in testis, epididymis and seminal vesicle of these hamsters. Such parasitism plays a role in the origin of genital lesions observed in humans and laboratory animals during chronic chagasic infection

Pancreatic hepatocytes in hamsters (Mesocricetus auratus) infected with Trypanosoma cruzi.

Hepatocytic metaplasia may be induced in hamsters by carcinogens, and associated with aging, diabetes or chronic pancreatitis. By means of histopathologic and immunohistochemic studies, we observed pancreatic hepatocytes in hamsters infected and reinfected with Trypanosoma cruzi. The change was seen in 18 (19%) out of 94 infected animals, and was not found among 53 controls, Normal islet cells were immunoreactive for neuron-specific enolase and not reactive for NCL-HAS. Metaplastic cells were immunoreactive for NCL-HAS and not reactive for islet hormones and enolase. No relationship was observed between number of inoculations and metaplasia; however, the intensity of the inflammatory process and sequels seems to favor the development of metaplastic cells. Hamsters infected with T. cruzi may be useful to study hepatocytic metaplasia, and contribute to clarify aspects of Chagas' disease and pancreatic changes. Our data indicate that aging, in addition to inflammation and atrophy, plays a role in this change.