Noise-induced gastric lesions: a light and electron microscopy study of the rat gastric wall exposed to low frequency noise / Lesões gástricas induzidas pelo ruído: um estudo por microscopia ótica e eletrônica da parede gástrica do rato exposta a ruído de baixa frequência

CONTEXT: Only a few studies evaluated the digestive alterations caused by low frequency noise (LFN) and most focused only on mucosal alterations. OBJECTIVES: To investigate the morphological injury of LFN-exposed gastric wall, beyond the epithelial layer. METHODS: Wistar rats were exposed to low frequency noise (LFN), during increasing periods, 1 to 13 weeks. A control group was kept in silence. Gastric specimens were studied using: (i) light microscopy with hematoxylin-eosin and immunostaining for collagens; (ii) transmission electron microscopy; (iii) morphometry allowing statistical analysis. RESULTS: Submucosa of all LFN-exposed animals exhibit increased thickness with fibrous proliferation. Transmission electron microscopy showed massive collagen deposition. Immunostaining identified collagen IV as responsible for the increased thickness. Morphometry allowed the demonstration of a significant difference of thickness between control and exposed groups. Vascular alterations included: i) intima proliferation and thickening, rupture of the internal elastic lamina, thrombotic changes; ii) thickening of the media; iii) after 9 weeks of LFN-exposure, we found new formed vessel presenting tortuous and twisted. There is a significant difference of arterial wall thickness between control and exposed groups. CONCLUSIONS: Deeper layers of gastric wall undergo alterations, including fibrosis of the submucosa caused by collagen IV deposition, an early marker of neoangiogenesis. Vascular alterations included thickening and thrombotic phenomena, but also images of newly formed vessels. This study suggests that, at least in the stomach, LFN-induced fibrosis could be linked with neoangiogenesis.

CONTEXTO: Só um reduzido número de estudos avaliou as alterações digestivas causadas pelo ruído de baixa frequência (RBF) e, na sua maioria, focados nas alterações da mucosa. OBJETIVO: Avaliar as lesões morfológicas induzidas na parede gástrica pelo RBF, para além da camada mucosa. MÉTODOS: Ratos Wistar foram expostos a RBF, por períodos crescentes, desde 1 a 13 semanas. Um grupo controle foi mantido em silêncio. Fragmentos da parede gástrica foram estudados com recurso a: (i) microscopia ótica usando hematoxilina-eosina e imunomarcação para colágenos; (ii) microscopia eletrônica de transmissão; (iii) morfometria, permitindo a colheita de dados para análise estatística. RESULTADOS: Observaram-se espessamento e proliferação de tecido fibroso na submucosa de todos os animais expostos aos RBF. A microscopia eletrônica de transmissão mostrou marcada deposição de colágeno. A imunomarcação identificou o colágeno IV como responsável pelo espessamento da submucosa. A morfometria permitiu demonstrar que a diferença de espessura da submucosa entre o grupo controle e os grupos de animais expostos era estatisticamente significativo. As alterações vasculares incluíram: (i) proliferação e espessamento da íntima, com rotura da lâmina elástica interna e fenômenos trombóticos; (ii) espessamento da média; (iii) após 9 semanas de exposição ao RBF, observaram-se vasos neoformados tortuosos e contorcidos. A espessura dos vasos dos animais expostos ao ruído é significativamente maior que a espessura no grupo controle. CONCLUSÕES: As camadas profundas da parede gástrica sofrem alterações que incluem fibrose causada pela deposição de colágeno IV, marcador precoce de neoangiogênese. As alterações vasculares incluem espessamento e fenômenos trombóticos e vasos neoformados. O presente estudo sugere que, pelo menos no estômago, a fibrose associada ao RBF pode estar ligada à neoangiogênese.

Does commercial aloe vera protects the structure of the gastric mucosa against acute nonsteroidal anti-inflammatory drug [diclofenac sodium]-induced damage?

Aloe plants have been used medicinally for centuries. Recent widespread importance of commercial aloe vera has encouraged scientists to scientifically assess these products. The aim of this study was to assess the possible protective role of oral commercial aloe vera on gastric mucosal acute damage induced by nonsteroidal anti-inflammatory drugs such as diclofenac sodium. Seventy adult male albino rats were divided randomly into four groups: group I [control], group II animals were given 200 mg/kg body weight of aloe vera once daily orally for 2 weeks, group III animals were administered a single oral dose of diclofenac sodium [80 mg/kg body weight] to induce acute gastric damage, group IV animals were given the same dose of aloe vera for 2 weeks followed by induction of acute gastric damage. Stomachs of animals of the four groups were studied macroscopically and microscopically. Morphometrical and statistical analyses were also carried out for determination of the percentage of area and depth of the mucosal lesion. This study showed that the percentage of area and depth of the mucosal lesions were significantly decreased in group IV in comparison with other groups. Microscopically, group IV and group III showed exfoliation of the surface epithelium, necrosis of some cells of the upper part of the gland, and loss of architecture of the basal part of the gland. Moreover, in group IV, periodic acid Schiff-Alcian blue-positive mucoussecreting cells appeared along the pits, neck, and isthmus with a thick periodic acid Schiff-Alcian blue-positive stained surface mucous film compared with a thin interrupted mucous film on the surface epithelium of the fundic mucosa in group III. Ultrathin sections showed predominance of mucous secretory cells with various types of mucoid granules in group IV. Commercial aloe vera provides a degree of protection against acute gastric mucosal damage mainly by increasing mucin secretion

Comparative study on the effect of long-term administration of non-steroidal anti-inflammatory drugs meloxicam and ketoprofen on the structure of the kidney and gastric mucosa in the adult albino rats

Ketoprofen is a widely used drug related to the group of the traditional non selective non-steroidal anti-inflamatory drugs [NSAIDs]. Meloxicam is related to the group of the cyclooxygenase-2 [COX-2] selective inhibitors which is a newer version of NSAIDs. To demonstrate and compare the effects of long-term administration of meloxicam and ketoprofen on the structure of the kidney and gastric mucosa in the healthy adult rats. A total number of 36 adult male albino rats were used in this study. They were equally divided into three groups. Group I was considered as a control. Group II included the rats treated with ketoprofen in a dose of 1mg/kg orally once daily for 10 weeks by a gastric tube, Group III included the rats treated with meloxicam in a dose of 0.2 mg/kg orally once daily for 10 weeks via gastric tube. At the end of the experiment animals were sacrificed and specimens of the kidney and stomach were processed for light and scanning electron microscopic studies. Some kidney specimens were also processed to be studied by transmission electron microscopy. The diameter of renal corpuscles was measured in the three studied groups and statistically analyzed. In ketoprofen treated rats [group II] the renal corpuscles exhibited marked shrinkage of glomeruli. Many renal tubules appeared to be lined with damaged epithelium. Ultrastructural study of the lining cells of the proximal and distal convoluted tubules revealed that the degenerative changes involved both the nucleus and the cytoplasmic organelles. The interstitial tissue had focal areas of fibrosis. In the meloxicam treated rats [group III], there was little shrinkage of the glomeruli. However, the interstitial tissue showed heavy cellular infiltration. SEM study revealed an enlargement of the processes of the podocytes with loss of their pedicles. The gastric mucosa in group II showed an extensive damage to the surface epithelial cells in the form of ulcers while in group III there was patchy areas of epithelial destruction. This study demonstrated that long-term administration of COX-2 selective inhibitors exerted deleterious effects on the kidney comparable to those exerted by the nonselective NSAIDs. However, their damaging effect on the gastric mucosa appeared to be less than the nonselective NSAIDs but it was not abolished

Modificaciones estructurales en el estómago y el hígado de Paralabrax maculatofasciatus (Steindacher, 1868) ante situaciones de estrés crónico / Structural modifications in the stomach and liver of Paralabrax maculatofasciatus (Steindacher, 1868) under chronic stress conditions

Para determinar el efecto del estrés a nivel del aparato digestivo, organismos de la especie Paralabrax maculatofasciatus fueron sometidos a dos modelos de estrés: el primero por descenso en el nivel del agua (n=84) por 30 y 60 minutos diariamente, y el segundo por cultivo a altas densidades (n=96) de 1,6 y 3,2 kg/100 1. Se tomaron muestras de estómago e hígado y se fijaron en formol al 10%. Los tejidos fueron incluidos en parafina, realizándose cortes de 6 um que se tiñeron con H-E. En ambas condiciones de estrés el estómago presentó cambios morfológicos importantes tales como hipertrofia y atrofia en la capa mucosa. En el hígado se observaron cambios de coloración y textura, así como hemolisis, inflamación y necrosis. Por descenso en el nivel del agua el estómago presentó diferencias morfométricas significativas (P<0,05), entre los diferentes tiempos de exposición al estrés y/o entre los días de muestreo en algunos de los parámetros medidos. Por cultivo a altas densidades, se observaron diferencias significativas en algunos parámetros, 4 de ellos presentaron interacción densidad-muestreo y el resto presentaron diferencias significativas sin interacción. El hígado presentó diferencias significativas (P<0,05) en el perímetro nuclear entre los diferentes días de muestreo. El estrés provocado por alta densidad de cultivo resultó ser el factor que provocó daños tisulares más severos en los órganos estudiados, de ahí la importancia de mantener las condiciones adecuadas en los cultivos, como son el nivel de agua y el número de organismos por estanque.

To determine stress effects at histological level in the digestive system, organisms of Paralabrax maculatofasciatus were submitted to 2 stress models. One of decreasing the water level (n=84) for 30 and 60 min daily, and another at high density cultures (n=96) of 1.6 and 3.2 Kg/1001. Stomach and the liver samples were fixed in 10% formalin, embedded in paraffin wax, sectioned at 6 urn and stained with haematoxylin-eosin. In both stress conditions, the stomach showed important morphological changes in the mucosa layer, such as hypertrophy and atrophy. In the liver, coloration and texture changes were observed as well as haemolisis, inflammation and necrosis. In the water decrease model, the mucosa layer of stomach showed significant morphometric differences (P<0.05), between different times of stress exposure and/or between different days, in some of the measured parameters. In the high-density model, significant differences in the stomach mucosa showed a sampling-density interaction in 4 parameters and 6 other parameters showed differences with no interaction. Liver showed significant differences in nuclear perimeter between sampling-days. Stress caused by high-density culture proved to be the factor that caused the most serious tissue damage.

Evaluation of the role of garlic on the structure of liver and gastric mucosa in aged male albino rat: a histological and histochemical study

Age related changes in the hepatic and gastric tissues have been discovered and are considered to be implicated in the pathogenesis of some diseases. To evaluate the effect of garlic as a prophylactic or a therapeutic tool against age related changes in the liver and stomach. 80 male albino rats were used. Classified into four groups: group 1: 15 rats served as control adult, group 2: 15 rats served as control aged, group 3: 25 adult rat treated with Tomax in a dose of 100 mg/kg orally daily till aging and group 4: 25 aged rats treated with Tomax in the same previous dose for 4 months. Animals were sacrificed and specimens from the liver and stomach were prepared for light and electron microscopy. Light and electron microscopic examination of liver and stomach of group 1 revealed the normal structure. Age related changes were detected in group 2 in the form of vacuolation of cells lining the gastric glands and disturbed hepatic architecture. Ultrastructurally, degenerative changes in parietal and chief cells were observed. Hepatocytes showed variable sized nuclei with marginated hetero chromatin clumps, areas of rarified cytoplasm, fragmented endoplasmic reticulum and interrupted cell membrane. Tomax treatment in group 3 greatly improved the aging changes in liver and gastric mucosa. Decreased vacuolation of gastric epithelial cells and restored hepatic architecture were observed. Ultrastructural degenerative changes were less pronounced in both tissues. In group 4 there was no obvious improvement but they were more or less similar to group 2. It could be concluded that garlic could be used as a prophylactic measure against age induced structural changes in the liver and stomach rather than being used as a therapeutic one

Microarchitectural adaptations in the stomach of African tree pangolin (Manis tricuspis) / Adaptaciones microarquitecturales en el estómago del pangolin africano (Manis tricuspis)

The microarchitecture of the pangolin's stomach favouring the high chitinous diet has been less waived into, despite extensive morphological investigations. Histological analysis of the microanatomy will provide powerful tools for interpretation to yield reliable insights. We investigated this by fixing the tissues in 10 percent formol saline for histological analysis. Serial sections at 5 micron m thickness were subjected to general staining methods for light microscopic study (Haematoxylin and eosin, Van Gieson's and Verhoeff's). The results revealed basic structural arrangements in their coats, with a modification of the epithelial lining of cardia and fundus into stratified squamous keratinized epithelium. These modifications were also reflected in the distribution of collagen and elastic fibers in the various layers (coats) of the stomach. The present study has shown that there was an adaptation of the stomach of African tree pangolin to its diet as reflected in the microarchitectural configuration.

La micro arquitectura del estómago de los pangolines que favorece la alta dieta de chitinous sido poco tomada en cuenta, a pesar de las amplias investigaciones morfológicas. El análisis histológico de la microanatomía proporcionará herramientas de gran importancia para la interpretación, junto con dar una información confiable. Se investigó mediante la fijación de los tejidos en solución salina de formol al 10 por ciento para análisis histológico. Las serie de secciones fueron sometidos a métodos de tinción estándar para el estudio con microscopía de luz (hematoxilina y eosina, Van Gieson y Verhoeff s). Los resultados revelaron adaptaciones estructurales básicas en sus capas, con una modificación del revestimiento epitelial del cardias y fundus en epitelio escamoso estratificado (queratinizado). Estas modificaciones también se reflejan en la distribución de colágeno y fibras elásticas en las diversas capas del estómago. El presente estudio ha demostrado que es una adaptación del estómago a la dieta como se refleja en la configuración de la microarquitectura.

Protective effect of Zuroor-e-Qula' against gastric mucosal damage: an ultrastructural study

The gastro-protective activity of the PHF [Zuroor-e-qula'] and its extracts was assessed in three different models of experimentally induced gastric ulcers in rats. In case of both preventive and curative treatments at 400 mg/kg dose the PHF and the aqueous and alcoholic extracts reduced gastric lesions significantly which were induced by HCl/ethanol. Significant changes in gastric parameters such as pH, volume of gastric juice and gastric acidity after oral administration of the samples under ligated pylorus [Shay] conditions. Also, in this paper, we report the ultrastructural observations of gastric mucosa. The ultrastructural changes were observed by Scanning Electron Microscopy [SEM]. The preventive as well as curative treatments in rats revealed a protective action against HCl/ethanol induced gastric mucosal damage. Probably, polyphenols, flavonoids, essential and fixed oils of the formulation were involved

Local and systemic effects of ketoprofen [a light and ultrastructural study]

Ketoprofen is one of the non steroidal anti-inflammatory drugs widely used in our population. Due to its easy access, drug abuse is very common leading to verious side effects. The effect of ketoprofen was seen on gastric mucosa and bone marrow of adult albino rats. Two regimen of the treatment were followed; either six regular interrupted doses, one week interval, given to starved rats or daily administration of the drug for six weeks. Samples from the gastric mucosa were examined both by light microscope and scanning electron microscope. Samples of the bone marrow were prepared for semithin sections, stained with toluidine blue, and examined by light microscope. Quantitative study was done using image analyser computer system. The data obtained was statistically analysed. Gastric lesions were demonstrated in both methods of treatment, although lesions were severer in chronic course. Bone marrow affection in the form of decreased granulocytic and increased erythrocytic precursors occurred only in chronically treated rats

Deteccao gastrica de Helicobacter pylori em pacientes pediatricos sintomaticos atraves da reacao em cadeia de polimerase (PCR), teste de urease e exame histologico / Gastric detection of Helicobacter pylori in symptomatic children through polymerase chain reaction, urease test and histological exam

Avaliar a PCR, o teste de urease e o exame histologico na deteccao do Helicobacter pylori no estomago de criancas sintomaticas...

Ultrastructural study of the effect of hydrocortisone on the fundic glands in albino rats and the possible protective role of lycopene

Hydrocortisone is widely used in the treatment of a variety of conditions. A common side effect of its use is gastritis and peptic ulceration. Lycopene is one of the major carotenoids in diet, particularly in tomato and tomato products. It is an active antioxidant that has recently received great concern for its protective effect against several pathological lesions. The aim of the present work was to evaluate the effect of hydrocortisone on the ultrastructure of fundic glands of albino rats and the possible protective effect of lycopene. The study was conducted on 20 adult male albino rats that were divided into four equal group: group I [control group], group II [positive control group] that received by gastric intubation a lycopene rich diet "Ketchup" which was calculated to equal a dose of 1 mg/Kg b.w./day, group III [treated group] that received intraperitoneal injection of hydrocortisone in a dose of 50 mg/Kg b.w./day, and group IV [protected group] that received lycopene simultaneously with hydrocortisone. The duration of the experiment was 20 days. Examination of the fundic glands of the treated group revealed ultrastructural changes in all the lining cells. In the protected group, such changes were almost completely absent

Morphologic considerations about the wall of the glandular stomach of young rabbits, oryctolagus cuniculus

La morfología del estómago puede variar de una especie a otra, en función de sus hábitos alimenticios, constitución celular de la mucosa de la pared estomacal y de las funciones realizadas por las células constituyentes. Variaciones morfofuncionales del estómago existentes entre los animales de la escala filogenética, nos llevaron a investigar la morfología de la pared del estómago glandular de los conejos. Utilizamos estómagos de 32 conejos (Oryctolagus cuniculus ), jóvenes, raza Neozelandés Blanco, provenientes de la Estancia Experimental de Iguatemí, de la Universidad Estadual de Maringá, Brasil. Los estómagos fueron recolectados y conservados en solución de Bouin; se les practicaron cortes de 5 y 12 µm, alcanzando la región que va desde la curvatura gástrica mayor hasta la curvatura gástrica menor, verificación histológica de rutina y coloración con Hematoxilina-Eosina, P.A.S. y Azan. Se observaron las muestras a través del microscopio óptico y luego fueron fotografiados. Observamos diferencias de estratisgrafía en la pared del estómago al comparar los cortes practicados en las curvaturas gástricas mayor y menor del estómago glandular de los conejos. Verificamos que la pared de la región glandular del estómago de los conejos presenta diferencias con relación a la morfología de las túnicas mucosa, submucosa, muscular y serosa, no presentando, por lo tanto, pared uniforme a lo largo de la circunferencia estomacal

Prelminary evaluation of quercetin effect on diclofenac sodium associated gastric ulcer in rats

The effect of quercetin [QRT] in preventing or reducing the diclofenac sodium-induced gastric ulcers was evaluated in rats following over night fasting by using a scanning electron microscopy. The scanning micrographs of stomach specimens showed a marked reduction in the gastric ulceration only when the quercetin is given before the administration of diclofenac sodium. The physicochemical characteristics of diclofenac sodium and quercetin combination were studied using differential scanning calorimetry, IR spectroscopy and X-ray diffractometery. The results revealed that a chemical incompatibility of diclofenac sodium and quercetin undoubtedly has been occurred when they were mixed in one combination. According to aforementioned results, we advise orally taking quercetin only before administration of diclofenac sodium as a prophylactic treatment to protect against its expected gastric disturbances

Histo-pathological, histo-chemical and ultrastructural changes of gastric mucosa in Egyptian patients with type C chronic active hepatitis [CAH]

Histopathological, histochemical and ultrastructural examinations of gastric mucosa were done in 20 cases with CAH post-virus C versus 20 healthy control individuals. The histopathological study of gastric mucosa in cases with type C CAH revealed chronic inflammatory cellular infiltrate with lymphocyte aggregation, hypoplasia of some glands with some cellular degeneration and an increase of fibrous tissues. There was a highly statistical significance between both groups regarding histopathological changes concerning histochemical changes of gastric mucosa in the diseased group. There was a highly statistical significant decrease of PAS positive-materials, succinic dehydrogenase and alkaline phosphatase stains and reactions, while there was a highly statistical significant increase of acidic phosphatase reaction as compared with the control group. The electron microscopic studies of gastric mucosa in cases with type C CAH revealed that oxyntic cells showed a decreased number of mitochondria with degenerative changes and peptic cells showing secretory granules, a decrease in the number of mitochondria, dilated endoplasmic reticulum and degenerative values

Comparative and morphologic evaluation of aspirin and ranitidine effects on wound repair of gastric mucosa

Esta investigación se realizó con el objetivo de verificar los efectos comparativos de la aspirina y de la ranitidina en la recomposición de la mucosa gástrica después de una agresión quirúrgica. La incisión quirúrgica, dentro de patrones definidos, fue efectuada en la mucosa gástrica de 12 ratones divididos en 3 grupos: placebo (PG), aspirina (AG) y ranitidina (RG). Las paredes gástricas y abdominal fueron suturadas en dos planos. A los ratones de los grupos PG, AG y RG se le administraron diariamente, por vía intragástrica, 1 ml de agua destilada, 250 mg/ka de aspirina y 25 mg/kg de ranitidina, respectivamente. Los estudios de la recomposición de la incisión en la mucosa en el 7º día pós-operatorio, a través de las microscopías de luz y electrónica de barrido, nos mostraron una reepitelización del tejido de granulación y de las células del epitelio que envuelven los bordes de la incisión quirúrgica. La importancia de las alteraciones fue observada de forma decreciente en la mucosa gástrica en los grupos AG, PG y RG

Electron microscopic observations in gastric mucosa of habitual tobacco chewers.

Clinical evaluation, upper gastrointestinal endoscopy and electron microscopy of mucosal biopsies from antrum, body and fundus of stomach were performed in three control subjects and 17 habitual tobacco chewers. Electron microscopic abnormalities such as discontinuous, fragmented basement membrane with reduction in hemidesmosomes, and widened intercellular spaces filled with clusters of desmosomes were found in the gastric mucosa of habitual tobacco chewers; these were similar to those reported in experimental carcinogenesis and leukoplakia. It is concluded that habitual chewing of tobacco produces electron microscopic alterations in the human gastric mucosa which may be important precursors for gastric malignancy.

Parietal cells contain most of the myosin, filamin and actin present in rat gastric glands

The association of myosin and a filamin-like protein to the F-actin cytoskeleton of parietal cells was studied in the rat gastric mucosa. Myosin and the filamin-like protein were localized by indirect immunofluorescence microscopy while the distribution of actin was established by using FITC-phalloidin. These cytoskeletal proteins, concentrated in the parietal cells, changed their distribution in correlation with the hydrochloric acid (HCl) secretory state of the cells and the appearance of a developed intracellular canaliculus. Thus,in resting parietal cells, actin showed a patchy distribution, delimiting the poorly developed secretory canaliculi, while myosin and the filamin-like protein distributed diffusely over the cytoplasm. In secreting cells, F-actin was concentrated in the cytoplasmic projections filling the canalicular lumen, while myosin and the filamin-like protein were excluded from this region, concentrating in the adjoining cytoplasm. The present results show that myosin and the filamin-like protein change their association with the secretory membranes in relation to the development of the secretory canaliculus of parietal cells. In resting cells, both proteins associate with the endocellular secretory membranes. In secreting cells, the microvillar projections of the canalicular surface formed by these membranes bind F-actin, but exclude myosin and the filamin-like protein

Differentiation of oxyntic cells and cell-matrix interactions during avian gastric gland morphogenesis

The relation between the expression of the oxyntic cell phenotype and the modifications of the extracellular matrix during development of the gastric glands, was studied in 10 to 21 day-old chick embryos. Cytodifferentiation of the oxyntic cells was established by ultrastructural methods, while the expression of pepsinogen, mitochondrial enzyme markers and apical secretory membranes was determined by histochemical and biochemical procedures. Results show that the morphogenesis of the glandular lobules occurs between days 8 and 15 of gestation. Later on, the lobules enlarge but maintain their basic morphology. Until day 13, the developing glands consist of primary tubes lined by a stratified columnar epithelium. The apical poles of the cells that contact the lumen show cytoplasmic processes, and Mg-ATPase activity and F-actin are concentrated at the apical cell borders. From day 13 on, the cells of the simple epithelium that lines secondary tubules budding from the primary tube, show all the features that define differentiated oxyntic cells. The synthesis of glycosaminoglycans during glandular morphogenesis was studied measuring the incorporation of radioactive sulfate into developing chick embryo proventriculi. An important increase in isotope incorporation was found between days 13 and 18 of development. Histochemical localization of these macromolecules shows that glycosaminoglycans are closely associated with the developing glandular lobules. Variations in the structure of epithelial cells undergoing morphogenesis and in the composition of the extracellular matrix are synchronous, suggesting that interactions between them may be significant in terms of the establishment and maintenance of the adult gastric gland phenotype

Análisis morfológico comparado de la región fúndica entre un cánido (canis familiaris) y un camélido sudamericano (lama glama) / Comparative morphological analysis of the fundic region between a canidae (canis familiaris) and a southamerican camelidae (lama glama)

Los hábitos alimentarios que presentan los cánidos (monogástricos) respecto de los camélidos (poligástricos), son diferentes. Los primeros consumen dietas pobres en fibras, en tanto que los camélidos consumen una dieta rica en fibra que consiste en pastos cortos y duros (bofedal). Sin embargo son capaces de aprovechar eficientemente estos alimentos. Por ello, fueron analizados comparativamente las regiones fúndicas de ambas especies, donde encontramos diferencias morfológicas adaptativas. Para la realización del presente trabajo, se obtuvieron muestras de las regionnes fúndicas, provenientes de estómagos de perro (Canis familiaris) y de llama (Lama glama), adultos. estas muestras fueron procesadas de acuerdo a las técnicas histológicas corrientes e histoquímica de Picrosirius y analizadas comparativamente al microscopio óptico. Los resultados revelaron que existen diferencias importantes en las regiones fúndicas de ambas especies en estudio. Estas diferencias se encuentran especialmente a nivel de la mucosa, donde la profundidad de las glándulas fúndicas, número de células parietales (oxínticas) y la irrigación sanguínea son mucho mayores en la llama. La pared abdomasal presenta un refuerzo de tejido conjuntivo compacto de haces paralelos, entre la serosa y la muscular longitudinal externa. Estas adaptaciones redundarían en una mayor eficiencia digestiva por parte de los camélidos, dadas las características de su dieta habitual

Absence of zinc cytotoxicity: Effect of short-term zinc oral administration on rat gastric mucosa

Zinc ions have been reported to stabilize cellular membranes, protecting the gastric mucosa against a wide variety of ulcerative agents. The treatment with zinc sulfate intragastrically administered as one dose (20 mg/Kg body weight) daily for 30 consecutive days did not modify the normal aspect of rat gastric mucosa as observed by electron sanning microscopy. Furthermore, the X-ray microanalysis of the lysosome content performed on different gastric mucosa cells did not show the zinc element. These results suggest that zinc ion is a relatively nontoxic element for the rat gastric mucosa