Anterior Esophagus Research Articles

Emprego da submucosa de intestino delgado na correção de estenose esofágica em cães

OBJETIVO: Pesquisar a eficácia da Submucosa de lntestino Delgado (SID) porcina na correção de estenoses esofágicas cervicais em cães. MÉTODOS: Para produzir estenose, 12 animais foram submetidos a ressecções de porção elíptica de 3,5X2,0 cm, na parede anterior do esôfago cervical, suturado por pontos de fio de algodão. O processo evolui por 90 dias, atingindo a estenose desejada e comprovada por esofagograma. Na seqüência, a lesão cicatricial produzida foi ressecada e substituída por enxerto de SID. Transcorridos 2 meses os animais foram submetidos a novo esofagograma. Aferiu-se então a largura esofágica (nas porções proximal e média do esôfago cervical) após a realização da estenose e pós-correção. Os animais foram submetidos a eutanásia, ao 60º dia de pós-correção, e à necropsia os esôfagos foram retirados e enviados ao laboratório de Anatomia Patológica. RESULTADOS: Não houve fístula ou infecção. Ocorreram reepitelização completa da mucosa, discreta reação infamatória e neovascularização moderada. A luz esofágica foi ampliada em 70% dos animais (43% ± 13% em média) (p = 0,2135). A medida da porção proximal, passou de 0,76cm para 0,95cm em média (p=0,02). Não houve alteração significativa em relação a porção medial. CONCLUSÃO: A SID demonstrou ser, no cão, enxerto eficaz para correção de estenoses esofágicas, integrando-se nitidamente à sua parede e substituindo-a de forma adequada.

Organization of the musculature of schistosome cercariae.

Phalloidin-fluorescein isothiocyanate staining of filamentous actin was used to identify muscle systems within the cercariae of Schistosoma mansoni. Examination of labeled cercariae by confocal scanning laser microscopy revealed distinct organizational levels of myofiber arrangements within the body wall, anterior cone, acetabulum, and esophagus. The body wall throughout showed a typical latticelike arrangement of outer circular and inner longitudinal myofibers, with an additional innermost layer of diagonal fibers in the anterior portion of the body. Circular and longitudinal fibers were also evident in the anterior organ and esophagus and, to some extent, the ventral acetabulum. Most striking was the striation of the cercarial tail musculature.

Localization of Transmissible and Nontransmissible Viruses in the Vector Nematode Xiphinema americanum

ABSTRACT The inner lining of the food canal of nematodes that transmit plantinfecting viruses is regarded as the retention region of viruses. To characterize the location of transmissible and nontransmissible viruses in the vector nematode Xiphinema americanum, three nepoviruses, Tobacco ringspot virus (TRSV), Tomato ringspot virus(TomRSV), and Cherry leaf roll virus(CLRV), and one non-nematode-transmissible virus, Squash mosaic virus (SqMV), were evaluated for transmission efficiency and localization sites in the nematode. Transmission trials showed highest transmission efficiency for TomRSV (38% with 1 and 100% with 10 nematodes, respectively), intermediate efficiency for TRSV (27% with 1 and 65% with 10 nematodes, respectively), and no transmission for CLRV and SqMV. Electron microscopy and immunofluorescent labeling revealed that TRSV was primarily localized to the lining of the lumen of the stylet extension and the anterior esophagus, but only rarely in the triradiate lumen. Within a nematode population, particles of TRSV were no longer observed in these three regions 10 weeks after acquisition, and it is assumed that there was gradual and random loss of the virus from these areas. The percentage of nematodes that were labeled by virus-specific immunofluorescent labeling in a population of viruliferous nematodes decreased gradually after TRSV acquisition when the nematodes were placed on a nonhost of the virus, and the loss of immunofluorescent labeling paralleled the decrease in the ability of the nematode population to transmit the virus. TomRSV was localized only in the triradiate lumen based on thin-section electron microscopy. No virus-like particles were observed in any part of the food canal of nematodes that had fed on CLRV-infected plants. Virus-like particles that appeared to be partially degraded were observed only in the triradiate lumen of nematodes that had fed on SqMV-infected plants. These results clarified the status of localization of two nontransmissible viruses in X. americanum and presented evidence that two nematode-transmissible viruses, TRSV and TomRSV, are localized in different regions of the food canal of X. americanum.

Safety and Efficacy of Laparoscopic Nissen Fundoplication in Early Infancy

Purpose: When gastroesophageal reflux (GER) is unresponsive to medical management, life-threatening complications may mandate surgical intervention in the very young. The aim of this study was to determine whether laparoscopic Nissen fundoplication in babies less than 3 months of age or 3.5 kg is safe and effective. Methods: The medical records from three institutions of all patients younger than 3 months of age or <3.5 kg undergoing fundoplication were reviewed. The short gastric vessels were routinely divided, and the crura were reapproximated. Short floppy 360° wraps were fashioned over a bougie (22F-30F) with two to four sutures incorporating the anterior esophagus. Laparoscopic Nissen fundoplication was performed in 104 infants fulfilling the size or weight criteria. Eighty two patient had concurrent gastrostomies. The mean age and weight were 68 days and 3.1 kg, respectively. Results: The mean operative time was 60 minutes, and the patients were at full feedings by a mean of 3 days. The mean patient...

Development and evolution of adult feeding structures in Caenogastropods: overcoming larval functional constraints.

Comparative study of the developing foregut in three species of caenogastropods, including an herbivorous grazer (Lacuna vincta) and two carnivores (Euspira [Polinices] lewisii and Nassarius mendicus), suggests how the specialized adult foregut of a carnivorous neogastropod evolved within a life cycle having a planktotrophic larva. Postmetamorphic feeding structures (buccal cavity and radular sac) in all three species achieve advanced differentiation in the larval stage, permitting juvenile feeding at 3 days postmetamorphosis. Recent phylogenetic hypotheses for the Gastropoda predict that foregut developmental patterns in E. lewisii and N. mendicus are derived, relative to that of L. vincta. In hatching larvae of these three, the anlage of postmetamorphic feeding structures is a small patch of nonciliated cells embedded in the ventral wall of the larval foregut and the patch soon forms an outpocketing. During subsequent morphogenesis, Euspira lewisii and N. mendicus share a developmental novelty that involves semi-isolation of the developing, postmetamorphic buccal cavity and radular sac from the larval foregut and formation of a new, definitive mouth at metamorphosis. Nassarius mendicus, a neogastropod, embellishes this novelty by adding the entire anterior esophagus and valve of Leiblein (de novo structures) to the semi-isolated buccal cavity. Therefore, a valve and long stretch of muscular anterior esophagus, which are necessary for feeding with a pleurembolic proboscis, are preformed in the larval stage of this neogastropod without interfering with larval feeding. The inferred evolutionary events leading to postmetamorphic feeding specialization in N. mendicus are invisible in adults; they require reconstruction from comparative developmental analysis.

Ultrastructure of the digestive tract of Gyliauchen nahaensis (Platyhelminthes, Digenea), an inhabitant of the hindgut of herbivorous fishes.

Digenean parasites of vertebrates usually amplify the surface area of their gut by increasing the size of the absorptive caeca. Some members of the family Gyliauchenidae, however, have relatively small caeca but have a greatly expanded foregut. The morphology of the elongate gut of the digenean Gyliauchen nahaensis, an inhabitant of herbivorous fish of the family Siganidae, was examined by light and transmission electron microscopy. The extensive foregut, consisting of a mouth, pharynx, and esophagus, is lined with a syncytial tegument-like lining, which is connected to nucleated cell bodies sunken in the parenchyma. The apical cytoplasm in the mouth and anterior regions of the pharynx resembles that of the general body tegument, although some regional specialization is present. The lining of posterior regions of the pharynx is armed with large apical projections, which are thought to serve as filtration structures. The lining of the anterior and middle esophagus displays a peculiar form of surface amplification involving the formation of elongate flask-shaped invaginations of the apical cytoplasm. The cell bodies associated with these regions are rich in secretory vesicles and it is proposed that these regions of the esophagus are expanded to promote extracellular digestion. The posterior region of the esophagus lacks the invaginations of other esophageal regions, but displays instead large surface projections. The caeca consists of columnar cells lined by extensive apical microlamellae. The peculiar gut morphology of G. nahaensis, coupled with alterations in the arrangement of suckers, is interpreted to be an adaptation to the predominantly herbivorous diets of the definitive hosts.

Unavoidable outcomes vs misadventures. Autopsy Committee of the College of American Pathologists.

48-YEAR-OLD man presented at the hospital and described a 22.5-kg weight loss and progressive difficulty swallowing over the past 6 months. The following day, an esophageal biopsy showed squamous cell carcinoma. Radiographic studies indicated liver metastases. The tumor was judged to be inoperable and palliative treatment included placement of an esophageal endoprosthesis (a metallic metal mesh tube) and chemotherapy with fluorouracil and cisplatin. One week later the patient had an episode of major hematemesis and cardiopulmonary arrest that could not be reversed with resuscitation. It was apparent that the underlying cause of death was most likely esophageal squamous cell carcinoma, but the patient’s physician requested an autopsy to determine the immediate cause of death and the cause of the terminal gastrointestinal hemorrhage, with special interest in evaluating whether death resulted from a mechanical complication of the stent or its placement. AUTOPSY FINDINGS Autopsy showed an ulcerating tumor mass in the midesophagus with hepatic metastases and local infiltration into the surrounding soft tissues and substernal soft tissue. An aortoesophageal fistula existed between the posterior aortic arch and the anterior mid-upper esophagus. Two additional posterior esophageal perforations were present: 1 near each end of the stent. The stent was intact and there was no evidence that the stent itself had caused a traumatic perforation of the esophagus. The thoracic cavity did not contain blood but the esophagus and stomach contained copious blood and blood clots. Microscopic sections of each perforation site showed extensive tumor necrosis with multiple areas of tumor ulceration and an acute inflammatory infiltrate. Malignant tumor cells were identified at all levels of the esophagus that were sampled. The aortic fistula site showed acute inflammation extending from the intima through the wall and into the periadventitial soft tissues and tumor infiltrate. Based on these findings, a cause of death statement could be prepared as follows: COMMENT

Trichinella spiralis: proteinases in the larvae.

Under in vitro conditions, muscle larvae of Trichinella spiralis secreted minute amounts of a cysteine proteinase into the outer environment from the stichosome. The proteinase hydrolyzed azocoll at pH 5.0 but not a number of synthetic N-blocked and N-unsubstituted proteinase substrates at this pH. The reducing compound dithioerythritol enhanced the enzyme activity, but the thiol-blocking reagent sodium-p-hydroxymercuribenzoate (0.1 mM) was without effect. Phenylmethylsulfonyl fluoride (PMSF) (2 mM) and leupeptin (100 mM) produced partial and complete inhibition, respectively, whereas soybean trypsin inhibitor, pepstatin A, and 1,10-phenanthroline were non-inhibitory. Calcium (1 mM) produced a slight decrease in the activity that was reversed by 1 mM EGTA. Although multiple proteinase activities were detected histochemically in the somatic muscles, stichosome, midgut, and genital primordium of the muscle larvae, none of these enzymes appeared to be the one secreted. Several histochemically demonstrable proteinases were also found in the cells of 48- to 72-h-old juveniles of the parasite. One was localized in the esophageal lumen and at or around the anterior esophagus of the larvae, where developing stichocytes are believed to occur. The proteinase hydrolyzed N-acetyl-L-methionine-L-naphthyl ester and was sensitive to the metal cation-complexing compound EGTA as well as to PMSF, an inhibitor of serine proteinases.

Ultrastructure of the foregut and associated glands in the lung fluke, Paragonimus miyazakii (Digenea: Troglotrematidae), with particular reference to their functional roles.

The foregut and associated glands of a digenetic trematode, Paragonimus miyazakii, were examined in the forebody by transmission and scanning electron microscopy as well as by light microscopy, and their functional roles were discussed. The foregut is lined with a general tegument without spines and sensory receptors throughout its length, although it consists of the mouth, pharynx, and esophagus. This foregut tegument is regionally and intraregionally modified in appearance, suggesting the performance of auxiliary functions in digestion. This appearance is characterized by long, frequent cytoplasmic extensions of the apical tegument around the middle portion of the mouth and the anterior esophagus. Electron-dense granules and multimembranous and multilamellar bodies are developed in the tegument to various degrees, and elaborately in the apical layer of the prepharynx. A single type of unicellular gland is embedded in the antero-middle part of the worm in small groups. The gland cells synthesize clear secretory granules as a chief product, each granule with a pleomorphic, dense, core-like inclusion. Mature granules are elliptical in shape, approximately 500 nm in diameter, and are subsequently discharged into the prepharyngeal foregut lumen after passing through the elongated cytoplasm of the gland cell. In the prepharynx and pharynx, host blood cells are apparently processed for digestion. In the wide lumen of the esophagus, foodstuff could undergo sufficient digestion prior to absorption by the cecal epithelium.

THE ONTOGENY OF THE PLEUREMBOLIC PROBOSCIS IN NUCELLA LAPILLUS (GASTROPODA: MURICIDAE)

The ontogeny of the proboscis in Nucella lapillus was investigated using light and scanning electron microscopy. The proboscis develops by elongation of the body wall surrounding the mouth, whilst the rhynchocoel is formed by imagination of the body wall surrounding the proboscis. Elongation of the snout during development of the proboscis results in the anterior movement of the anterior oesophagus and part of the mid-oesophagus (the valve of Leiblein) which is drawn through the circum-oesophageal nerve ring. The acinous salivary glands and the radular sac also come to lie anterior to the nerve ring. The mid-oesophageal gland of Leiblein and the glandular dorsal folds are not drawn through the nerve ring, and develop behind it. The anterior oesophagus elongates at a later stage of development to produce the oesophageal length required for extension of the adult proboscis. Modifications to this sequence of events, or changes in the rate of growth of the various parts of the foregut, might account for the differences between the neogastropod and neotaenioglossan pleurembolic proboscis. The intraembolic proboscis found in the Conoidea and the Pseudolivoidea may have been derived via a modification of the developmental sequence which produces the muricoidean pleurembolic proboscis.

Feeding behaviour in Cylindrophis and its bearing on the evolution of alethinophidian snakes

Cylindrophis ruffus ingests prey using two distinct mechanisms. During initial phases of prey transport, lateral movements of the rear of the braincase combine with small unilateral movements of the toothed bones of each side; prey is usually constricted during this phase to permit the snake to push its head over the prey. Once transport has carried the leading part of the prey into the anterior oesophagus, Cylindrophis begins to use bilaterally synchronized movements of the jaw apparatus combined with low‐amplitude, short wave‐length flexions of the anterior vertebral column. Transport of prey is many times faster during the bilateral phase than during the unilateral phase.Radiographic and cinematographic evidence indicates that the mandibular tips of Cylindrophis do not separate more than 1.5–2.0 times the resting distance between the dentary tips. Although this limits potential gape size, the intramandibular joint is highly mobile, allowing the mandibles to conform to a variety of prey shapes. Manipulations of anaesthetized and fresh, dead specimens revealed that the palatomaxillary arches are tightly attached to the ventral bones of the snout, movements of each arch being reflected in equivalent movements of the ipsilateral elements of the snout. Cylindrophis represents a functional stage intermediate between most lizards with limited palatomaxillary kinesis and advanced snakes with considerable palatomaxillary mobility. Contrary to previous hypotheses, however, upper jaw liberation in Cylindrophis is due to liberation of the ventral snout, not to reduction of attachments to the braincase and snout. This suggests that the nose played a crucial role in the evolution of the feeding apparatus in alethinophidian snakes.

Heterotopic pig model for direct revascularization and venous drainage of tracheal allografts

A macrosurgical technique of thyrotracheal harvesting and direct revascularization with and without venous drainage in a heterotopic thyrotracheal and immunosuppressed allograft in the pig model is described. Harvesting included en bloc cervicothoracic exenteration of the aortic arch and its supraortic trunks, anterior vena cava, jugular veins, subclavian vessels, thyroid gland, cervicothoracic trachea, and esophagus. This technique conserves the tracheal arterial supply provided by either the right or left subclavian artery, directly or indirectly via the inferior thyroid artery, and venous return provided by the anterior vena cava, directly or indirectly via the descending cervical vein. In recipients, implantation included (1) arterial end-to-end anastomoses of the proximal and postscalenic stumps of donor's subclavian artery to the proximal and prescalenic stumps of recipient's subclavian artery; (2) end-to-side venous anastomosis of the donor's anterior vena cava to the recipient's brachiocephalic venous trunk; and (3) heterotopic implantation of the proximal and distal orifices of the grafted trachea into the neck. Ten adult Large White pigs underwent direct revascularization of a thyrotracheal allograft with (n = 6, group 1) and without (n = 4, group 2) venous drainage. All grafts of group 2 exhibited a venous infarction, extensive inferior thyroid artery thrombosis, and ischemic and suppurative thyrotracheal necrosis 1 to 2 days after transplantation. In group 1, the length of the grafted trachea and number of rings were 9.75 +/- 1.5 cm and 22.1 +/- 3.3, respectively; ischemic time was 236.3 +/- 338.3 minutes. Group 1 pigs were put to death 4 (n = 4) and 3 (n =2) weeks after transplantation. All tracheal grafts had histologically normal airway epithelium; isolated areas of necrotic ischemia of the chorion and submucosa lasted for the first 7 days after transplantation but disappeared after epithelial regeneration. Premortem angiograms showed that all vascular anastomoses were patent. Grafts were histologically normal at postmortem examinations and all but one had no rejection. This large animal model demonstrates that long tracheal allografts might be transplanted by means of this direct revascularization and venous drainage technique.

Small cardioactive peptide B increases the responsiveness of the neural system underlying prey capture reactions in the pteropod mollusc, Clione limacina.

Effects of small cardioactive peptide B (SCPB) on cerebral neurons which underlie prey capture in the carnivorous pteropod mollusc, Clione limacina, were investigated. SCPB in concentrations of 10 microM and higher produced direct activation of cerebral ganglion neurons underlying extrusion of buccal cones used in prey capture. SCPB in lower concentrations, between 1 and 5 microM, did not have a noticeable effect on the membrane potentials of these neurons; however, it significantly increased their responsiveness to sensory inputs from the tactile stimulation of the head, and their ability to generate afterdischarge activity. SCPB immunoreactivity was observed in cell bodies in buccal, cerebral, pedal, and intestinal ganglia, as well as in the anterior esophagus and in buccal cones where fibers stained intensely. These electrophysiological and immunohistochemical data suggest that SCPB may have a physiological role in feeding arousal in Clione.

A New Bioassay for the Investigation of a Membrane-Associated Ecdysteroid Receptor in Decapod Crustaceans

A new bioassay was designed to test the sensitivity and structure specificity of the membrane-associated ecdysteroid receptor in decapod crustaceans. The oesophagus dilatation assay (ODA) is based on an immediate reflex-like dilatation of the anterior oesophagus that occurs in decapod crustaceans in response to overcritical concentrations of ecdysteroids.

Predatory shell drilling by two species of Austroginella (Gastropoda: Marginellidae)

Predatory shell drilling of bivalve mollusc shells is reported for the gastropods Austroginella johnstoni and A. muscaria from south-eastern Australia. This is the first record of this feeding behaviour in the family Marginellidae. The drill holes are circular and paraboloid, with a small inner penetration hole. The corroded nature of the aragonite crystals within the drill holes suggests a chemical dissolution drilling mechanism. No obvious accessory boring organ was located. The gastropods have subepithelial gland cells in the proboscis, a pair of small salivary glands and a large foregut gland. The latter has a duct bypassing the valve of Leiblein and joining the anterior oesophagus.

The digestive tract of the amberjack Seriola dumerili, Risso: a light and scanning electron microscope study

The histology of the digestive tract of the amberjack (Seriola dumerili, Risso) was studied using light and scanning electron microscopy. The anterior oesophagus mucosa displays primary and secondary folds lined with a stratified squamous epithelium with fingerprint‐like microridges which is substituted, on the top of the oesogaster folds, by a simple columnar epithelium with short microvilli. Only primary folds are present in the stomach. The anterior portion is rich in simple tubular glands, whereas the oesogaster and the pyloric region are devoid of them. Pyloric caeca and anterior and middle intestine mucosa display the same pattern of folding. The dominant cell type is the enterocyte, which exhibits larger and thinner microvilli in the caeca than in the intestine. The columnar epithelium of the rectum is replaced, in the anal sphincter, by a stratified flattened epithelium. Goblet cells are numerous throughout the whole length of the tract with the exception of the initial part of the oesophagus, the oesogaster, the stomach and the anal sphincter. Mucosubstances have been shown to vary in the different regions of the gut: acid mucines are found in the oesophagus, pyloric stomach, caeca, intestine and rectum, whereas neutral mucosubstances dominate in the anterior portion of the stomach. The muscularis is well developed throughout the length of the tract: two layers of striated muscle at the oesophageal level; two layers of smooth muscle in the stomach wall and three at the intestinal level.

Laboratory observations on the feeding behaviour, reproduction and morphology of Galeodea echinophora (Gastropoda: Cassidae)

Galeodea echinophora fed on Echinocardium cordatum in an aquarium. Every few days, each G. echinophora emerged from the sand and foraged for 1–3 h. On detecting an Echinocardium, the Galeodea stopped locomotion and attacked the buried prey from the surface of the sand. The proboscis was extended down to the prey and a small area of test was cleared of spines. A disc was cut out of the softened test, leaving a hole of about 2 mm in diameter. All flesh except the gut was removed from the prey, the entire procedure taking 50–180 min. One Galeodea echinophora laid 120 egg capsules on the side of the aquarium. These were kept at 13oC and hatched after 112–159 days. Within the capsule, veligers fed on the yolk cells of abortive embryos. Juveniles hatched at the crawling stage, and at first secreted strings of mucus acting as drogues, but after 1 day the juveniles crawled over the substratum. They readily attached themselves to adult Echinocardium cordatum, apparently feeding on the epithelium between the spines or tube feet. Dissection revealed entry of the acinar glands into the proboscis gland ducts, a widening of these ducts as they empty into the buccal cavity and a dorsal fold in the anterior oesophagus. Radular teeth and jaws of Galeodea differ little among species; a taxonomic review of the genus is needed.

Species of Discolaimus (Nematoda: Dorylaimoidea) From Australia

Five species of Discolaimus collected from Australian mallee soils are described: D. major, D. texanus and three new species. In each species the lip region is an expanded, saucer shaped disc with distinct rim, divided by grooves into six sectors on the anterior surface, and variously lobed on the under surface. D. agricolus n. sp., monosexual, L = 1.30-1.73 mm, V = 45-48, odontostyle = 21-23 μm, has a multi-lobed lip region similar to D. major and an anterior oesophagus of uniform diameter throughout. D. silvicolus n. sp., monosexual, L = 1.16-1.89 mm, V = 51-53, odontostyle 20-22 μm, has a distinctively lobed lip region and prominent sheath around the basal oesophageal expansion. D. elegans n. sp., monosexual, L = 1.11 to 1. 20 mm, V = 50-53, odontostyle 14-15 μm, has three rows of lateral body pores. In D. major, D. agricolus and D. silvicolus a group of large cells of unknown function is present in the cardiac region. Two subventral longitudinal grooves in the odontostyle and numerous ventral and dorsal body pores are present in all five species.

A study of the innervation of the anterior esophagus of Busycon canaliculatum—I. Innervation pattern and evidence of the presence of catecholaminergic neurohumors

1. 1. The distal and proximal segments of the anterior esophagus of Busycon canaliculatum were examined for the presence of biogenic amines using histochemical and chromatographic techniques. 2. 2. Glyoxylic acid treatment of the esophagus, esophageal nerve and buccal ganglia revealed green fluorescing, catecholaminergic, varicose axons. 3. 3. Chromatographic analysis using high performance liquid chromatography indicated the presence of dopamine in all structures containing fluorescent nervous structures. 4. 4. The possible function of dopamine in the esophageal musculature is considered.

Scanning electron microscopic study of the gut mucosa of the rainbow trout Salmo gairdneri Richardson.

The topological characteristics of the entire gut surface of the rainbow trout were investigated utilizing the scanning electron microscope. The mucosa exhibited longitudinal ridges in the oesophagus and stomach, villi in the intestine, fine longitudinal ridges in the caeca and annular folds in the rectum, arranged as a stack of caudally‐directed funnels starting from the intestino‐rectal valve to the vent. Detailed study revealed taste pores in the anterior oesophagus and the sculpting of the luminal plasmalemma of the surface cells into micro‐ridges with complicated patterns. The surfaces of the posterior oesophagus and stomach were demarcated into polygons by rows of stubby microvilli—each polygon representing the luminal surface of an epithelial cell. Each rectal fold consisted of a smooth, caudally‐directed apex and a base which was supported by perpendicular buttress‐like secondary folds. The functional significance of these features which emphasize the vast difference in the physical length of the gut and the effective surface area is discussed.