Burrow plugging in the crab Uca uruguayensis and its synchronization with photoperiod and tides.

Field observations and laboratory experiments were performed to analyze the burrow plugging behavior of U. uruguayensis and to analyze its relation to two environmental cycles: light-dark cycle and tides. Field observations showed that burrow plugging is a rhythmic behavior synchronized with both environmental cycles such that burrows are open during those periods of simultaneous light and low tide. Laboratory experiments suggested that the plugging rhythm is under endogenous circadian control, whereas its synchronization with the tidal cycle, particularly with periodic inundation, seems to be strongly exogenous, not showing clear circatidal components. It is proposed that burrow plugging is adaptive because it allows the animals to be within an air medium, more suitable for their respiration modality, during high tide and because it prevents burrow collapse. It is also proposed that both the endogenous circadian component and the lack of an endogenous circatidal component can also be explained on the basis of adaptive value, taking into account the regular temporal structure of the solar day and the irregular temporal structure of the tidal cycle.

Serological markers identify histologically latent coeliac disease among first-degree relatives.

BACKGROUND AND AIM: Serological markers detect asymptomatic coeliac disease among first-degree relatives of patients with sprue. However, some relatives with coeliac disease-related antibodies have 'normal' jejunal mucosa by conventional histology. Whether these serological abnormalities represent false-positives or are consequences of gluten sensitivity is not known. Our aim was to evaluate, through quantitative histology, intestinal biopsies of asymptomatic relatives of probands seeking abnormalities consistent with latent coeliac disease. MATERIALS: Fifty-nine intestinal biopsies obtained from asymptomatic relatives were evaluated; 40 samples were suitable for histological quantification. Seven samples showed severe mucosal atrophy (coeliac disease) and 33 were considered as 'normals'. In the 'normal' group, nine samples were obtained from patients with one or more positive serological tests and 24 from those with negative tests. Morphometry was compared for samples obtained from healthy control individuals (n = 10) and for those from coeliac patients (n = 7). METHODS: Serological tests used were: antigliadin antibodies type immunoglobulin (Ig)A and IgG (enzyme-linked immunosorbent assay), antirrecticulin antibody (immuno-fluorescence) and endomysial antibody (immunofluorescence). Biopsy samples were obtained with endoscopic forceps from the distal duodenum (second portion). Quantitative histology of duodenal biopsies was performed with a computerized image analysis system. RESULTS: Relatives with positive serology showed shorter villi (P < 0.05) and higher number (P < 0.01) and numerical density (P < 0.01) of intraepithelial lymphocytes in crypts than healthy controls. Numerical density of intraepithelial lymphocytes in crypts in antibody-positive patients was significantly higher than that observed in relatives with negative serology (P < 0.03). Four of nine (44%) relatives with positive serology had a number of intraepithelial lymphocytes in crypts within the range of coeliac disease patients. However, only one patient with negative serology (4%) was in this range. CONCLUSION: Our study shows quantitative histological evidence that relatives of probands with positive coeliac disease-related serology are not false-positives, and that they should be considered as individuals with latent coeliac sprue.

Immunocytochemical distribution of corticotropin-releasing factor in the brain and hypophysis of larval Bufo arenarum; effect of KClO4 during early development.

The maturation of the corticotropin-releasing factor (CRF) neuronal system was evaluated by immunocytochemistry and morphometry in Bufo arenarum, during spontaneous metamorphosis and in tadpoles with inhibited thyroid function. The first appearance of CRF immunoreactive fibers was at the end of premetamorphosis (stage VIII). These fibers were found in small numbers and weakly stained in the median eminence and infundibular stalk. With the advance of larval development, CRF-like material stained intensely and tended to aggregate in the external zone of the median eminence. At climax stages, immunoreactive fibers and perikarya (weakly stained) were identified in the interpeduncular nucleus and in the dorsal infundibular nucleus. Morphometric and immunocytochemical results indicate that the maturation of the CRF neuronal system in Bufo arenarum occurs just before metamorphic climax, coinciding with high levels of thyroid and steroid hormones. We have also found that in larvae with inhibited thyroid function, the CRF neuronal system is able to develop, and that thyroid hormone could exert a negative feedback control on the synthesis of CRF.

[Helicobacter pylori detection by polymerase chain reaction in gastric juice and its correlation with the histology (Giemsa)]. / Detección del Helicobacter pylori por reacción en cadena de polimerasa en jugo gástrico y su correlación con la histología (GIEMSA).

HP infection is involved in the pathogenesis of several gastroduodenal diseases, as type B chronic gastritis, duodenal and gastric ulcer, MALT lymphoma and gastric cancer. The recent availability of molecular techniques, specifically the PCR, allow us to detect very low amounts of the bacterium. The aim of the study is to evaluate the presence of HP in gastric juice by PCR technique and to correlate this findings with histology (Giemsa) of gastric mucosa. Gastric juice PCR positive findings were found in 10/31 (32.3%) HP positive patients at histology. We concluded that HP in gastric juice is possible to detect by molecular techniques. In our study 32.3% of the patients showed the presence of HP in gastric juice.

[Methodology for the detection and analysis of activity patterns]. / Metodología para la detección y análisis de patrones de actividad.

A simple method for the recording of animal activity patterns is described, based upon a transduction made with piezoelectric sensors attached to a modified cage. The signal is then filtered and digitalized, and can be stored for later analysis.

Immunocytochemical and morphometric study of TSH, PRL, GH, and ACTH cells in Bufo arenarum larvae with inhibited thyroid function.

Changes in the pituitary cells involved in amphibian metamorphosis were studied in Bufo arenarum tadpoles with inhibited thyroid function. After hatching, larvae were treated for 5 months with potassium perchlorate (KClO4), a goitrogenic substance known to prevent absorption of iodine from water or food, resulting in impaired thyroid hormone synthesis. Treated larvae continued to grow but halted their development in premetamorphosis, showing hyperplastic thyroid glands with disorganized follicles lacking colloid. Thyrotrop (TSH), lactotrop (PRL), somatotrop (GH), and corticotrop (ACTH) cells were stained immunocytochemically and the changes observed were evaluated morphometrically using an automatic image analyzer. Pars distalis volume increased in treated larvae. Morphometric results showed that, in treated tadpoles, TSH and PRL cell populations and cell volumes increased compared to normal larvae at the same stage. Changes in the GH and ACTH cell morphometry were slight. These results indicate that in Bufo tadpoles, after chronic thyroid hormone withdrawal, TSH, PRL, GH, and ACTH cells are able to develop and that thyroid hormones exert a strong feedback control on the synthesis and storage of TSH and PRL.

Absence of apnea in armadillos covered by soil.

The armadillo Chaetophractus villosus shows a remarkable respiratory adaptation when the nostrils are completely covered by soil: it is able to maintain efficient respiratory movements with the corresponding filling of the lungs, thanks to a mechanism that allows it to use the air filling the space between the soil particles, without invasion of the nasal cavities by those particles.

Immunocytochemical and morphometric study on the changes of TSH, PRL, GH and ACTH cells during the development of Bufo arenarum.

The development and dynamics of thyrotropin (TSH), adrenocorticotropic hormone (ACTH), prolactin (PRL), and growth hormone (GH) cells have been studied using immunocytochemical techniques and rabbit antisera, raised against the relevant human hormone, in the pars distalis of Bufo arenarum larvae at different stages of development. The four types of cells studied were identified in different zones of the pars distalis: TSH cells occurred mainly in the centro-ventral zone, ACTH cells in the rostral and dorsal zones, GH cells in the central and caudal zones, and PRL cells in the anterior two-thirds of the gland. This distribution pattern does not show significant changes with development. Morphometry and stereology were used to evaluate the changes observed in the volume of the pars distalis and the immunoreactive cells during development. The former increased during larval growth and decreased throughout the metamorphic climax. The results obtained on cell number, volume density, and total volume suggest that, during larval growth (pre-prometamorphosis) of B. arenarum, TSH, PRL, GH and ACTH cells show a proliferative period with storage of their hormones; a second period involving hormone release occurs at the metamorphic climax.

The natural history of gluten sensitivity: report of two new celiac disease patients resulting from a long-term follow-up of nonatrophic, first-degree relatives.

OBJECTIVE: Early studies revealed that up to 50% of non-atrophic, first-degree relatives of celiac disease patients exhibit features of gluten sensitivity. However, whether these features progress to a fully expressed celiac disease remain partially known. Our aim was to report two new patients resulting from a prospective, long-term surveillance of relatives who were nonatrophic at initial assessment. METHODS: After a median time of 86 months (range: 42-102 months) from the baseline assessment, we re-evaluated 44 first-degree relatives of propositi who had taken part in family studies and in whom baseline small intestinal biopsies were normal. At the baseline screening, 21 relatives had positive serum antigliadin antibodies and/or increased intraepithelial lymphocyte infiltration, and 23 did not. In addition, 11 of 18 had a celiac-like response to rectal gluten challenge and 16 of 34 possessed the characteristic HLA DQ2 haplotype (DQA1 0501 DQB1 0201). Re-evaluation was based on celiac-related serology antigliadin (AGA) and endomysial (EmA) antibodies. EmA-positive subjects underwent intestinal biopsy. RESULTS: At the end of the study, EmA was positive in only two subjects. Histological examination revealed flat small bowel mucosa in both. At baseline, both cases were EmA-negative and no minor histological changes were observed. One was a woman with positive baseline IgA and IgG AGA and a rectal gluten challenge with a celiac-like response; the other patient has presented only with a positive IgG AGA. In both cases, progression was detected in a clinically silent context. Both new patients had the characteristic HLA DQ2 haplotype. CONCLUSIONS: Our data suggest the need to re-evaluate relatives who have been negative on initial screening for celiac disease. Up to now, the progression to severe enteropathy was only observed in relatives who had presented some evidence of gluten sensitivity and the characteristic HLA DQ2 haplotype. Longer longitudinal studies are necessary to obtain definitive conclusions.

Time course of nitric oxide synthase generation after gluten exposure in the rectal mucosa of gluten-sensitive patients.

BACKGROUND: Nitric oxide is thought to play an important role in modulating chronic inflammatory responses as well as in immune-mediated inflammation. We reproduced a gluten-mediated mucosal response in the rectum of celiac and control subjects in order to determine the role of inducible and constitutive nitric oxide synthases in the pathogenesis of this process. MATERIAL: Nine patients with confirmed celiac disease and five healthy controls underwent a long-term rectal gluten challenge (48 h) after an enema of 6 g of crude gluten, and constitutive and inducible nitric oxide synthase activity were determined in rectal biopsies. The histological localization of inducible nitric oxide synthase was determined by immunohistochemistry. RESULTS: Activity of both isoforms of nitric oxide synthase in control subjects did not change significantly after gluten instillation. In celiac patients, constitutive nitric oxide synthase on rectal mucosa also showed no significant changes after challenge with gluten. Inducible nitric oxide synthase isoform exhibited a modest increase 4 h after gluten instillation in celiac patients (mean increase 35% compared with baseline levels) but, 8 h after challenge, generation of iNO synthase was significantly higher: 54% more than pre-challenge production (P < 0.05) and higher than control values (P < 0.05). Inducible nitric oxide synthase staining was mostly localized in mononuclear cells of the epithelium and the lamina propria. After gluten instillation, the enhanced staining was mainly localized in subepithelial areas of the lamina propria. CONCLUSION: Our data suggest a role for nitric oxide, generated by inducible nitric oxide synthase, in the process of rectal mucosa injury by local gluten instillation in sensitized patients. We could not, however, determine if the role of nitric oxide in the ensuing injury of this gluten-induced immune inflammation model is a protective one, or merely a by-product generated by the activation of the inflammatory cells.

Gluten sensitivity in patients with primary biliary cirrhosis.

OBJECTIVE: Whereas celiac disease and primary biliary cirrhosis have been reported to coexist in the same patient, the frequency of this relationship has not been clarified. Nowadays, the concept of celiac disease has been extended from that of a severe enteropathy to a broader concept of gluten-driven intestinal immunological response. In this study we assessed features of gluten sensitivity in a cohort of patients with primary biliary cirrhosis. METHODS: Ten patients with primary biliary cirrhosis were evaluated a mean of 2 yr after diagnosis. The following features of gluten sensitivity were assessed: serum antigliadin and endomysial antibodies, small bowel histology (degree of atrophy and quantitative histological parameters), the presence of the typical celiac HLA genotype (DQ2), and intraepithelial lymphocyte response in the rectal mucosa after local gluten instillation (rectal gluten challenge). RESULTS: Overall, three patients presented evidence of gluten sensitivity. All three had abnormal titers of antigliadin antibody type IgA and one was positive for endomysial antibody. Two patients had partial villous atrophy. The rectal gluten challenge showed a celiac-like response, evidenced by an increase in intraepithelial lymphocyte infiltration after gluten exposure, in the three patients. The characteristic celiac HLA genotypes (DQA1 0501 and DQB1 0201) were identified in three patients. One of them also exhibited other features of gluten sensitivity. However, despite evidence of gluten intolerance, patients had minimal or no symptoms characteristic of celiac disease. CONCLUSION: We detected features of gluten sensitivity in a high proportion of patients with primary biliary cirrhosis. Further studies should be performed to elucidate the clinical significance of this association.

Usefulness of videoduodenoscopy and vital dye staining as indicators of mucosal atrophy of celiac disease: assessment of interobserver agreement.

BACKGROUND: The present study was designed to determine the diagnostic usefulness of videoduodenoscopic inspection alone and the addition of vital dye staining in the detection of celiac disease. We additionally sought to evaluate interobserver agreement for specific duodenoscopic markers of mucosal atrophy. METHODS: One hundred sixty-seven consecutive subjects who underwent duodenoscopy for intestinal biopsy were included in a prospective controlled study. Endoscopic examination was performed by experienced endoscopists according to a set protocol using methylene blue (1%) dye. All procedures were recorded on videotape, but only 20 (10 with atrophy and 10 normal) were used in a blinded, independent, randomized analysis by five reviewers to evaluate interobserver agreement. Endoscopic signs indicative of mucosal atrophy were as follows: reduction in the number or loss of Kerkring's folds, "scalloped" folds, "mosaic pattern," and visualization of the underlying blood vessels. RESULTS: Eighty-seven patients had celiac disease (57 newly diagnosed, 30 when treated). Seven treated patients had nonatrophic mucosa. In 80 patients the final diagnosis excluded celiac disease. Videoendoscopic inspection alone correctly identified 75 of 80 patients with complete mucosal atrophy and 86 of 87 with normal mucosa. False-negative diagnoses occurred in treated celiac patients with mild atrophy. Mosaic pattern (89%) and scalloped folds (86%) were the most useful endoscopic signs. Vital dye staining, as assessed by experienced endoscopists, provided identical results to those obtained by inspection alone. Sensitivity, specificity, and positive and negative predictive values for the presence of one or more than one feature were 94%, 100%, 100%, and 96%, respectively. The agreement (kappa statistics) among observers was excellent for the mosaic pattern (kappa: 0.76 for both the videoendoscopic inspection alone and dye staining) and the scalloped folds (kappa: 0.83 and 0.76, respectively) and was fair (kappa: 0.41 and 0.59, respectively) for the reduction in the number or loss of duodenal folds. CONCLUSION: This study confirms that videoduodenoscopy is useful in the detection of intestinal atrophy. Dye staining produces a better delineation of scalloped folds and mosaic pattern in the atrophic mucosa, but did not provide additional information to the expert endoscopist. Finally, interobserver agreement was excellent for the most prevalent signs.

Gluten sensitivity in the rectal mucosa of first-degree relatives of celiac disease patients.

BACKGROUND/AIMS: Rectal gluten challenge is a simple, sensitive, and specific test of mucosal gluten sensitivity. Our aims in this study were to evaluate gluten sensitivity in a group of relatives of celiac patients and to compare these findings with those obtained on small bowel histology, celiac disease-related serology, and HLA typing. METHODS: A 4-h rectal gluten challenge was performed with 6 g of crude gluten in saline solution in 29 first-degree relatives, 20 well-diagnosed celiac patients, and 10 subjects in whom celiac disease had been excluded. The number of intraepithelial lymphocytes in pre- and postchallenge frozen rectal biopsies (pan T-cell immunocytochemistry) was quantified by computerized image analysis. RESULTS: The intraepithelial lymphocyte response after gluten instillation was significantly higher in celiac disease patients (median, 126% increase above the baseline count; 95% confidence interval: 61-213%) compared with control subjects (median, -5%; 95% confidence interval: -29-5%). Using a cut-off of 20% change in intraepithelial lymphocyte count, 14 relatives (48%) showed a celiac-like response. Two of these subjects had partial villous atrophy and increased lymphocyte counts in the small bowel mucosa. One of them also exhibited a positive celiac disease-related serology and the typical celiac human lymphocyte antibody (HLA) DQ2. The remaining 12, and all those relatives with a negative challenge, had normal small bowel mucosa and were negative for antigliadin and endomysial antibodies. The characteristic celiac HLA (DQA1 0501 DQB1 0201 heterodimer) was identified in five relatives with positive challenge (including the patient with more severe mucosal atrophy) but was also present in eight relatives with no evidence of gluten sensitivity in the rectal mucosa. CONCLUSIONS: Our study characterizes a subgroup of relatives of celiac patients who show mucosal evidence of sensitization after local instillation of gluten in the rectum but who have no other features of celiac disease.

Deteccion del Helicobacter pylori por reaccion en cadena de polimerasa en jugo gastrico y su correlacion con la histologia (Giemza) / Helicobacter pylori detection by in gastric juice and its correlation with the histology (Giemsa)

Mediante técnicas de biología molecular (PCR), hemos podido detectar la presencia de HP en el jugo gástrico en la tercera parte (10/31 pacientes - 32,3 por ciento) de los infectados con la bacteria, según determinación histológica. La demostración de la presencia de HP en jugo gástrico permitirá a traves de nuevos estudios mejorar los conocimientos acerca de los mecanismos de diseminación y complementar la metodología diagnóstica.