Ultrastructure of the excretory duct in the silk gland of the sugarcane borer Diatraea saccharalis (Lepidoptera : Pyralidae)

The excretory duct in the silk gland of the sugarcane borer Diatraea saccharalis consists of two morphologically distinct regions, recognized by scanning and transmission electron microscopy. The thin posterior region, adjacent to the glandular region, presents a regular surface. Secretory vesicles containing either electron-dense or fibrillar cuticular-like materials are observed in their apical cytoplasm; the same cuticular materials were detected as extracellular deposits among the microvilli. The short anterior region, near the common duct, exhibits surface protrusions; there are no secretory vesicles in their apical cytoplasm. These results show that only the duct cells at the posterior region are involved in the secretion of the cuticular intima elements. Desmosome-like structures were visualized linking together adjacent microvillar membranes only in the cells of anterior duct region, with unknown function. The transition between the duct and the glandular region is abrupt; the cells of the glandular and posterior duct regions present large amounts of microtubules. Nerve fibers can be observed between the duct cells in their two regions, suggesting that control of silk secretion may occur in the excretory duct via neurotransmitter liberation. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Isolation of Campylobacter jejuni from viscera and bile secretion of broiler chickens with diarrhea

Since chickens are important reservoirs of Campylobacter jejuni and their meat is the most frequent route of transmission for human campylobacteriosis, the purpouse of the present study was to investigate the presence of Campylobacter in viscera of chickens with diarrhea, evaluating the frequency of isolation of this microorganism from organs considered to be preferential for its isolation. A total of 107 visceral samples from chickens with diarrhea from different farms in the Ribeirao Preto region, SP, were examined for the presence of Campylobacter jejuni. The material consisted of 73 livers and 34 spleens, plus 29 bile secretion samples. The frequency of Campylobacter jejuni isolation was 54.79% for the liver samples, 35,29% for the spleens and 6,89% for the bile secretion samples. The data suggest that, under the conditions of the present study, the liver may be the organ of choice for the isolation of Campylobacter in the presence of diarrhea and liver involvement in chickens.

The element-free Galerkin method applied to the study of fully developed magnetohydrodynamic duct flows

In this paper, the meshless method is introduced to magnetohydrodynamics. A numerical scheme based on the element-free Galerkin method is used to solve the laminar steady-state two-dimensional fully developed magnetohydrodynamic flow in a rectangular duct. Accurate and convergent solutions are achieved for low to moderately high Hartmann numbers.

An application of the Adomian's decomposition method to the analysis of MHD duct flows

A new approach is proposed in this work for the treatment of boundary value problems through the Adomian's decomposition method. Although frequently claimed as accurate and having fast convergence rates, the original formulation of Adomian's method does not allow the treatment of homogeneous boundary conditions along closed boundaries. The technique here presented overcomes this difficulty, and is applied to the analysis of magnetohydrodynamic duct flows. Results are in good agreement with finite element method calculations and analytical solutions for square ducts. Therefore, new possibilities appear for the application of Adomian's method in electromagnetics.

REDUCTION OF CELL PROLIFERATIVE ACTIVITIES OF GASTRIC STUMP ADENOMATOUS HYPERPLASIAS AFTER BILE REFLUX DIVERSION IN RATS

Previously we reported the majority of lesions induced hy bile reflux, in the absence of chemical carcinogens, in the rat remnant stomach to consist primarily of gastric type and secondarily of intestinal type cells, and that they are reversible after diversion of bile reflux. The present study was designed to evaluate changes in proliferative activities in cells of each type under these conditions. The frequency of adenomatous hyperplasia (AH) induced in the gastric stump mucosa by duodenal content reflux after Billroth II partial gastrectomy (BII) increased until the 54th week of the experiment. Roux-en-Y (RY) surgical procedure which prevents duodenal reflux performed at the 24th or 36th week after BII led to a decrease in AH. Cell content of the lesions was analyzed using routine H&E staining, immunohistochemical staining for pepsinogen isoenzyme 1 and histochemical procedures for mucins (paradoxical concanavalin A, galactose oxidase Schiff and sialidase galactose oxidase Schiff reactions) and proliferation in each compartment evaluated by an immunohistochemical method using bromodeoxyuridine (BrdU) and a monoclonal antibody against BrdU. At the 54th week the number of BrdU-labeled cells per normal pyloric column was significantly (P < 0.05) increased to 10.63/pit after the BII operation, while it diminished to 5.23/pit after RY diversion, this being the same level as with the RY procedure alone. AH maintained a high rate of BrdU incorporation at 12.7% after BII operation, which was also significantly reduced (P < 0.01) to 7.0% by the RY surgery. The intestinal type cell showed highest (22.2%), the surface mucous type cell showed the next (16.5%) and the pyloric gland type cell showed lowest (5.2%) BrdU labeling indices after BII operation. All the cell types in AH showed similar proportional decreases in BrdU incorporation after RY diversion. Thus surgical intervention reverses the cell proliferation caused by bile reflux in the gastric stump.

Three-dimensional finite element analysis of MHD duct flow by the penalty function formulation

A numerical scheme based on the Finite Element Method (FEM) is presented to calculate the full solution of a three-dimensional steady magnetohydrodynamic (MHD) flow with moderately high Hartmann numbers and interaction parameters. An incompressible, viscous and electrically conducting liquid-metal is considered. Assuming a low magnetic Reynolds number, the solution method solves the coupled Navier-Stokes and Maxwell's equations through the use of a penalty function method. Results are presented for Hartmann numbers in the range 10(2)-10(3).

Gingival metastasis from salivary duct carcinoma of the parotid gland

Background: This article reports a rare case of metastasis of salivary duct carcinoma of the parotid gland to the gingiva and reviews the occurrence of metastatic processes to the oral mucosa.Methods: A 67-year-old white male presented with a chief complaint of a painless nodular tissue growth on the gingiva with reportedly 5 months of evolution. The intraoral examination revealed a reddish, superflcially ulcerated nodular lesion (similar to 2 cm in diameter) on the right mandibular buccal attached gingiva, and the clinical aspect was that of a benign reactive lesion. The patient had undergone a parotidectomy for removal of a salivary duct carcinoma of the parotid gland almost 1 year before. A biopsy of the gingival lesion was performed, and the biopsied tissue was forwarded for histopathologic examination.Results: The analysis of the histopathologic sections of the gingival lesion revealed histomorphologic characteristics very similar to those of the primary parotid gland tumor. The definitive diagnosis was gingival metastasis from a salivary duct carcinoma of the parotid gland. The patient died of complications of a pulmonary metastasis I month after the diagnosis of the oral metastatic lesion.Conclusions: Gingival lesions that mimic reactive and hyperplastic lesions may be metastases from malignant neoplasias of diverse origins. An accurate and timely diagnosis is crucial to establish proper and immediate treatment of the metastatic tumor and possibly identify an occult primary malignant neoplasia.