Morphological study of adult male worms of Schistosoma mansoni Sambon, 1907 by confocal laser scanning microscopy

Aiming to detail data obtained through brightfield microscopy (BM) on reproductive, excretory and digestive system, specimens of Schistosoma mansoni eight weeks old, were recovered from SW mice, stained with Langeron's carmine and analyzed under a confocal laser scanning microscope CLSM 410 (Carl Zeiss). The reproductive system presented a single and lobate testis, with intercommunications between the lobes without efferent duct. Supernumerary testicular lobe was amorphous and isolated from the normal ones. Collecting tubules (excretory ducts), followed by the excretory bladder, opening to the external media through the excretory pore, were observed at the posterior extremity of the body. In the digestive tract, a cecal swelling was noted at the junction that originates the single cecum. It was concluded that through confocal laser scanning microscopy, new interpretations of morphological structures of S. mansoni worms could be achieved, modifying adopted and current descriptions. The gonad consists of a single lobed testis, similar to that observed in some trematode species. Moreover, the same specimens can be observed either by BM or CLSM, considering that the latter causes only focal and limited damage in tissue structures.

Apport du bleu de toluidine en cancérologie bucco-pharyngo-oesophagienne [Contribution of Toluidine blue to bucco-pharyngo-oesophageal cancerology]

En muqueuse malpighienne lisse, le Bleu de Toluidine présente un intérêt diagnostic considérable, non seulement lors de l'endoscopie, mais lors de la chirurgie d'exérèse des carcinomes intra-épithéliaux et micro-invasifs de la voie digestive supérieure (bouche, pharynx, oesophage). L'utilisation systématique de ce colorant vital nous a permis le diagnostic et l'étude morphologique endoscopique de 18 carcinomes « précoces » de l'oesophage (9 in situ, 3 dysplasies sévères, 1 microinvasif, 5 limités à la sous-muqueuse). La multicentricité et la multifocalité de ces lésions est fréquente (80 à 90 % des cas), ce qui impose leur exérèse chirurgicale sous Bleu de Toluidine, afin de détecter les foyers de carcinome in situ à distance de la lésion primaire. La connaissance exacte des faux positifs et négatifs permet de limiter les erreurs d'interprétation lors de la coloration.

Penetration Sites and Migratory Routes of Angiostrongylus costaricensis in the Experimental Intermediate Host (Sarasinula marginata)

The intermediate hosts of Angiostrongylus costaricensis are terrestrian molluscs, mostly of the family Veronicellidae. The present work aimed at clarifying more accurately the sites of penetration and the migratory routes of A. costaricensis in the tissue slugs and at verifying the pattern of the perilarval reaction at different times of infection. Slugs were individually infected with 5,000 L1, and killed from 30 min to 30 days after infection. From 30 min up to 2 hr after infection, L1 were found within the lumen of different segments of the digestive tube having their number diminished in more advanced times after exposition until complete disappearance. After 30 min of exposition, percutaneous infection occurred, simultaneously to oral infection. Perilarval reaction was observed from 2 hr of infection around larvae in fibromuscular layer, appearing later (after 6 hr) around larvae located in the viscera. A pre-granulomatous reaction was characterized by gradative concentration of amebocytes around larvae, evolving two well-organized granulomas. In this work we confirmed the simultaneous occurrence of oral and percutaneous infections. Perilarval reaction, when very well developed, defined typical granulomatous structure, including epithelioid cell transformation. The infection also caused a systemic mobilization of amebocytes and provoked amebocyte-endothelium interactions.

Epidemiology of Chagas disease in Ecuador. A brief review

Chagas disease is a complex public health problem that has been underestimated in Ecuador. Here we review the relevant published information, and present unpublished and new data that help to understand the current Chagas disease epidemiological situation and its evolution in the country. Three main characteristics have been identified: (i) persistence of Trypanosoma cruzi transmission in already known foci; (ii) a marked endemicity in some urban areas of Guayaquil; and (iii) the transformation of new Amazon foci into truly endemic areas. The situation in other suspect areas remains uncertain. Five Triatominae species have been implicated in the transmission of T. cruzi to people in Ecuador (Triatoma dimidiata, Rhodnius ecuadoriensis, R. pictipes, R. robustus and Panstrongylus geniculatus), but some others may also play a role in some areas (P. rufotuberculatus, P. howardi, T. carrioni and P. chinai). Other Triatominae reported seem to have little or no epidemiological relevance (T. venosa, T. dispar, Eratyrus mucronatus, E. cuspidatus, P. lignarius and Cavernicola pilosa). High frequency of acute cases and severe chronic disease has been observed. Although cardiomyopathy is more frequent, serious digestive disease is also present. It is estimated that around 120,000-200,000 people may be infected. 2.2 to 3.8 million people are estimated to live under transmission risk conditions.

Selection of Trypanosoma cruzi clonal genotypes (clonet 20 and 39) isolated from Bolivian triatomines following subculture in liquid medium

Previous studies showed that two groups of Trypanosoma cruzi clonal genotypes named clonet 20 and clonet 39 were predominant in Triatoma infestans, the unique vector of Chagas disease in Bolivia. These groups of clones correspond to distinct genetic clusters. These clonets were detected in T. infestans and Rhodnius pictipes fecal samples before isolation and after culture by kDNA PCR (polymerase chain rreaction) and hybridization of the amplified products with clonet specific kDNA probes named 20 and 39 as previously reported. Forty eight T. infestans and three R. pictipes infected insects captured at random in different Bolivian departments were proceeded. As previously reported the direct identification of the two major clonets in fecal samples allowed the detection of abundant mixed infections: 41% in the original sample, however after culture, only 6% of mixed infections were detected. Among the 21 parasite stocks isolated from digestive tracts where mixed infections were initially detected (clonet 20 + 39) clonet 20 alone was detected in 81% of them. This result clearly showed that the culture step selected clonet 20 parasites over those belonging to clonet 39. The taxonomic status of the isolated stocks was also confirmed by isoenzyme typing, and correlation was observed between clustering topology and hybridization patterns with the probes 20 and 39.

Colitis induced in mice with dextran sulfate sodium (DSS) is mediated by the NLRP3 inflammasome.

BACKGROUND: The proinflammatory cytokines interleukin 1beta (IL-1beta) and IL-18 are central players in the pathogenesis of inflammatory bowel disease (IBD). In response to a variety of microbial components and crystalline substances, both cytokines are processed via the caspase-1-activating multiprotein complex, the NLRP3 inflammasome. Here, the role of the NLRP3 inflammasome in experimental colitis induced by dextran sodium sulfate (DSS) was examined. METHODS: IL-1beta production in response to DSS was studied in macrophages of wild-type, caspase-1(-/-), NLRP3(-/-), ASC(-/-), cathepsin B(-/-) or cathepsin L(-/-) mice. Colitis was induced in C57BL/6 and NLRP3(-/-) mice by oral DSS administration. A clinical disease activity score was evaluated daily. Histological colitis severity and expression of cytokines were determined in colonic tissue. RESULTS: Macrophages incubated with DSS in vitro secreted high levels of IL-1beta in a caspase-1-dependent manner. IL-1beta secretion was abrogated in macrophages lacking NLRP3, ASC or caspase-1, indicating that DSS activates caspase-1 via the NLRP3 inflammasome. Moreover, IL-1beta secretion was dependent on phagocytosis, lysosomal maturation, cathepsin B and L, and reactive oxygen species (ROS). After oral administration of DSS, NLRP3(-/-) mice developed a less severe colitis than wild-type mice and produced lower levels of proinflammatory cytokines in colonic tissue. Pharmacological inhibition of caspase-1 with pralnacasan achieved a level of mucosal protection comparable with NLRP3 deficiency. CONCLUSIONS: The NLRP3 inflammasome was identified as a critical mechanism of intestinal inflammation in the DSS colitis model. The NLRP3 inflammasome may serve as a potential target for the development of novel therapeutics for patients with IBD.

Underutilization of upper gastrointestinal endoscopy.

BACKGROUND & AIMS: Efforts to reduce costs in health care may raise concerns about underuse of medical procedures. This study prospectively assessed underuse of upper gastrointestinal endoscopy in a cohort of patients in whom we have recently published data on overuse of endoscopy. METHODS: Underuse was identified by formal necessity criteria for endoscopy, obtained by an explicit panel process. Outpatients were consecutively included in two clinical settings. Setting A consisted of 20 primary care physicians and 7215 patient visits that occurred within 1 month. Setting B consisted of 920 visits that occurred during 3 weeks at an outpatient clinic. RESULTS: During these 8135 visits, 611 patients complained of upper digestive symptoms; 63 of them underwent endoscopy. Underuse was identified in 72 patients (11.8%). The two clinical situations mainly responsible for underuse of endoscopy were uninvestigated peptic symptoms resistant to treatment and dysphagia. At first follow-up, 29 of the patients with initial underuse still fulfilled criteria of necessity (underuse rate, 4.7%). One-year follow-up showed underuse of endoscopy in 5 patients. CONCLUSIONS: This prospective evidence shows that underuse of a medical procedure exists. The estimated overuse and underuse of endoscopy in this cohort were approximately equal (5%). Improving quality of care will require reductions of both overuse and underuse of medical procedures.

Immunodéficience commune variable: ce qu'il faut savoir [Common variable immune deficiency: what you need to know].

Common variable immune deficiency is the most frequent primary immune deficiency, characterized mainly by a disorder of B lymphocytes differentiation and a deficit in immunoglobulins. The clinical manifestations include recurrent infections, non-infectious lung and digestive involvements, autoimmune diseases, and an increased susceptibility to cancers. Recent breakthroughs have been made in the understanding of some genetic mechanisms of the disease. Replacement therapy with intravenous immunoglobulins remains the treatment of choice, which allows significant improvement in the survival and quality of life. However progress should be made in the understanding of the pathophysiology and in the early detection of this disease, since a delay in the diagnosis may have harmful consequences in terms of morbidity and mortality.

Gut-derived signaling molecules and vagal afferents in the control of glucose and energy homeostasis.

PURPOSE OF REVIEW: The control of glucose and energy homeostasis, including feeding behaviour, is tightly regulated by gut-derived peptidic and nonpeptidic endocrine mediators, autonomic nervous signals, as well as nutrients such as glucose. We will review recent findings on the role of the gastrointestinal tract innervation and of portal vein glucose sensors; we will review selected data on the action of gastrointestinally released hormones. RECENT FINDINGS: The involvement of mechanosensory vagal afferents in postprandial meal termination has been clarified using mouse models with selective impairments of genes required for development of mechanosensory fibres. These activate central glucogen-like peptide-1/glucogen-like peptide-2 containing ascending pathways linking the visceroceptive brainstem neurons to hypothalamic nuclei. Mucosal terminals comprise the chemosensory vagal afferents responsive to postprandially released gastrointestinal hormones. The mechanism by which the hepatoportal glucose sensor stimulates glucose utilization by muscles was demonstrated, using genetically modified mice, to be insulin-independent but to require GLUT4 and AMP-kinase. This sensor is a key site of glucogen-like peptide-1 action and plays a critical role in triggering first phase insulin secretion. PeptideYY and ghrelin target intracerebral receptors as they are bidirectionally transported across the blood brain barrier. The anorectic functions of peripherally released peptideYY may however be mediated both via vagal afferents and intracerebral Y2 receptors in the brainstem and arcuate nucleus. SUMMARY: These recent findings demonstrate that the use of improved anatomical and physiological techniques and animal models with targeted gene modifications lead to an improved understanding of the complex role of gastrointestinal signals in the control of energy homeostasis.

Paper de la quinasa IKKalpha al càncer colorectal

Prèviament havíem identificat la presència d’una forma de l’IKKα de 45kD que s’expressa específicament en el nucli de les cèl.lules de cancer colorectal. A més havíem demostrat que aquesta forma estava fosforilada la qual cosa suggereix que es tracta d’una forma activa d’IKKa. Un dels objectius que ens varem plantejar va ser determinar el mecanisme per el qual es generava aquesta forma de la quinasa. Mitjançant eines bioinformàtiques hem identificat possibles llocs de processament proteolític en la seqüència d’IKKα que podrien ser responsables de generar el fragment de 45kD present en les cèl.lules tumorals. Després, hem demostrat que les proteases identificades in silico són capaces de processar IKKa in vitro, específicament en els llocs predits. S’ha pogut constatar, mitjançant la mutació dels possibles llocs de processament, que només un dels llocs identificats bioinformàticament corresponent a Cathepsin B/L era funcional in vitro, mentre que els altres llocs predits no ho eren. D’igual manera, l’expressió ectòpica de la Cathepsin B o L és capaç de produïr el processament d’IKKα. Pel contrari, la inhibició de l’activitat de la proteasa mitjançant inhibidors específics és capaç de bloquejar el processament d’IKKa en cèl.lules tumorals. Finalment, hem demostrat que els nivells de la Cathepsin B i L, proteases identificades com a responsables de processar IKKa es troben sobre-expressades en la majoria de les mostres humanes de càncer de colon analitzades comparat amb el teixit normal adjacent del mateixos pacients.

Gregarine Cephaloidophora communis mawrodiadi, 1908 in the barnacle Euraphia rhyzophorae, Oliveira, 1940 from Brazil

The gregarine Cephaloidophora communis was observed for the first time in Brazil in the barnacles Euraphia rhyzophorae collected in Angra dos Reis, Rio de Janeiro, Brazil, between 1990 and 1996. Histological studies showed growth phases of the parasite in specific parts of the digestive system. The intracellular forms occurred in the vacuoles of the intestinal cells. Syzygy was frequent, and the most common form following syzygy was cylindrical, with a single membrane. The cytoplasm of the gregarines was always irregular, dense, and occasionally presenting a dark stoch area.

Small Bowel Bacterial Overgrowth is found in 71% of IBS patients and associated symptoms respond wel to Rifaximin in a phase IV trial

Background: The prevalence of small intestinal bowel bacterial overgrowth (SIBO) in patients with irritable bowel syndrome (IBS) ranges from 43% to 78% as determined by the lactulose hydrogen breath (LHBT) test. Although rifaximine, a non-absorbable antibiotic, has been able to decrease global IBS symptoms as well as bloating in placebo-controlled randomized trials, these results were not repeated in phase IV studies in daily clinical practice. Aim: To assess the prevalence of SIBO in an IBS cohort and to evaluate the treatment response in the IBS cohort affected by SIBO. Methods: Enrolled patients were diagnosed with IBS using the following criteria: fulfillment of the Rome III criteria, absence of alarm symptoms (anemia, weight loss, nocturnal symptoms etc), normal fecal calproectin, normal endoscopic workup including histology. Celiac disease was excluded by serology and/or duodenal biopsy. All patients underwent lactulose hydrogen breath testing (LHBT) for SIBO diagnosis. Patients with SIBO were treated with rifaximine tablets (400mg twice daily for 14 days). Both before and at week 6 after rifaximin treatment, patients completed a questionnaire, where the following criteria were assessed individually using 11-point Likert scales: the bloating, flatulence, abdominal pain, diarrhea, and overall well-being. Results: Hundred-fifty IBS patients were enrolled (76% female, mean age 44 ± 16 years), of whom 106 (71%) were diagnosed with SIBO and consequently treated with rifaximine. Rifaximine treatment significantly reduced the following symptoms as assessed by the symptom questionnaire: bloating (5.5 ± 2.6 before vs. 3.6 ± 2.7 after treatment, p <0.001), flatulence (5 ± 2.7 vs. 4 ± 2.7, p = 0.015), diarrhea (2.9 ± 2.4 vs. 2 ± 2.4, p = 0.005), abdominal pain (4.8 ± 2.7 vs. 3.3 ± 2.5, p <0.001) and resulted in improved overall well-being (3.9 ± 2.4 vs. 2.7 ± 2.3, p <0.001). Thirteen of the 106 treated patients were lost to follow-up (12%). The LHBT was repeated 2-4 weeks after rifaximine treatment in 65/93 (70%) patients. Eradication of SIBO was documented in 85% of all patients (55/65), whereas 15% of patients (10/65) tested positive for SIBO as determined by the LHBT testing. Conclusions: The results of our phase IV trial indicate that a high proportion of IBS patients tested positive for SIBO. IBS symptoms (bloating, flatulence, diarrhea, pain, overall well-being) were significantly diminished following a 2-week treatment with rifaximine. These results support the previous findings of randomized controlled trials that the presence of SIBO is associated with symptom generation in IBS patients and that reduction and/or elimination of SIBO may help to alleviate IBSassociated symptoms.

Surgical indication in Schistosomiasis mansoni portal hypertension: follow-up from 1985 to 2001

The study had the objective to evaluate the benefits of surgical indication for portal hypertension in schistosomiasis patients followed from 1985 to 2001. Schistosoma mansoni eggs were confirmed by at least six stool examinations or rectal biopsy. Clinical examination, abdominal ultrasonography, and digestive endoscopy confirmed the diagnosis of esophageal varices. A hundred and two patients, 61.3% male (14-53 years old) were studied. Digestive hemorrhage, hypersplenism, left hypochondrial pain, abdominal discomfort, and hypogonadism were, in a decreasing order, the major signs and symptoms determining surgical indication. Among the surgical techniques employed, either splenectomy associated to splenorenal anastomosis or azigoportal desvascularization, esophageal gastric descompression and esophageal sclerosis were used. Follow-up of patients revealed that, independent on the technique utilized, a 9.9% of death occurred, caused mainly by digestive hemorrhage due to the persistence of post-treatment varices. The authors emphasize the benefits of elective surgical indication allowing a normal active life.