Numerical modeling of fiber specklegram sensors by using finite element method (FEM).

Although experimental advances in the implementation and characterization of fiber speckle sensor have been reported, a suitable model to interpret the speckle-pattern variation under perturbation is desirable but very challenging to be developed due to the various factors influencing the speckle pattern. In this work, a new methodology based on the finite element method (FEM) for modeling and optimizing fiber specklegram sensors (FSSs) is proposed. The numerical method allows computational visualization and quantification, in near field, of changes of a step multi-mode fiber (SMMF) specklegram, due to the application of a uniformly distributed force line (UDFL). In turn, the local modifications of the fiber speckle produce changes in the optical power captured by a step single-mode fiber (SSMF) located just at the output end of the SMMF, causing a filtering effect that explains the operation of the FSSs. For each external force, the stress distribution and the propagations modes supported by the SMMF are calculated numerically by means of FEM. Then, those modes are vectorially superposed to reconstruct each perturbed fiber specklegram. Finally, the performance of the sensing mechanism is evaluated for different radius of the filtering SSMF and force-gauges, what evidences design criteria for these kinds of measuring systems. Results are in agreement with those theoretical and experimental ones previously reported.

Spontaneous autoimmune gastritis and hypochlorhydria are manifest in the ileitis-prone SAMP1/YitFcs mice.

SAMP1/YitFcs mice serve as a model of Crohn's disease, and we have used them to assess gastritis. Gastritis was compared in SAMP1/YitFcs, AKR, and C57BL/6 mice by histology, immunohistochemistry, and flow cytometry. Gastric acid secretion was measured in ligated stomachs, while anti-parietal cell antibodies were assayed by immunofluorescence and enzyme-linked immunosorbent spot assay. SAMP1/YitFcs mice display a corpus-dominant, chronic gastritis with multifocal aggregates of mononuclear cells consisting of T and B lymphocytes. Relatively few aggregates were observed elsewhere in the stomach. The infiltrates in the oxyntic mucosa were associated with the loss of parietal cell mass. AKR mice, the founder strain of the SAMP1/YitFcs, also have gastritis, although they do not develop ileitis. Genetic studies using SAMP1/YitFcs-C57BL/6 congenic mice showed that the genetic regions regulating ileitis had comparable effects on gastritis. The majority of the cells in the aggregates expressed the T cell marker CD3 or the B cell marker B220. Adoptive transfer of SAMP1/YitFcs CD4(+) T helper cells, with or without B cells, into immunodeficient recipients induced a pangastritis and duodenitis. SAMP1/YitFcs and AKR mice manifest hypochlorhydria and anti-parietal cell antibodies. These data suggest that common genetic factors controlling gastroenteric disease in SAMP1/YitFcs mice regulate distinct pathogenic mechanisms causing inflammation in separate sites within the digestive tract.

Henipavirus: a review of laboratory animal pathology.

The genus Henipavirus contains two members-Hendra virus (HeV) and Nipah virus (NiV)-and each can cause fatal disease in humans and animals. HeV and Niv are currently classified as biosafety level 4, and NiV is classified as a category C priority pathogen. The aim of this article is to discuss the pathology of laboratory animal models of henipavirus infection and to assess their suitability as animal models for the development and testing of human therapeutics and vaccines. There has been considerable progress in the development of animal models for henipavirus disease. Suitable animal models include the golden hamster, ferrets, cats, and pigs, which develop disease resembling that observed in humans. Guinea pigs are a less reliable model for henipavirus disease, but they do develop henipavirus-induced encephalitis. Because human efficacy studies with henipaviruses are not permitted, animal studies are critical for the development of antiviral therapeutics and vaccines. Current research indicates that passive immunotherapy using monoclonal antibodies is protective of ferrets against NiV infection and that passive immunotherapy using NiV antibodies protects hamsters from HeV. Recombinant vaccines have been used to protect cats and pigs against NiV infection. Ribavirin and 6-aza-uridine were able to delay but not prevent NiV-induced mortality in hamsters. Further research is needed to develop a model and therapy for late-onset henipavirus encephalitis.

Localization of fibropapilloma-associated turtle herpesvirus in green turtles (Chelonia mydas) by in-situ hybridization.

Fibropapilloma-associated turtle herpesvirus (FPTHV) is the presumed aetiological agent of sea turtle fibropapillomatosis (FP). Intralesional DNA and RNA of the virus have been detected by polymerase chain reaction (PCR) and reverse transcriptase-PCR (RT-PCR), respectively, but the exact location and distribution of the virus within the tumours have not been addressed. In this study, in-situ hybridization (ISH) was used to investigate viral transcriptional activity and localization of FPTHV. Twenty-five tumours were obtained from the skin or conjunctiva of 105 green turtles (Chelonia mydas) examined on two islands in Puerto Rico (Culebra and Culebrita). These lesions comprised 19 fibropapillomas and six fibromas. FPTHV mRNA transcripts were detected by ISH in three fibropapillomas, with positive reactions confined to the nuclei of clusters of epithelial cells. Viral DNA was detected by riboprobe ISH combined with denaturation in 14 tumours, including both fibropapillomas and fibromas. Signals were confined to the nuclei of acanthotic epithelial cells and were not seen in the subepithelial fibrous areas of the tumours. These results suggest that FPTHV is present in epithelial cells and transcriptionally active in fibropapillomas.

Histopathologic and immunohistochemical characterization of Nipah virus infection in the guinea pig.

Mortality rate in humans infected with Nipah virus (NiV) has been reported as high as 92%. Humans infected with NiV show a widespread multisystemic vasculitis with most severe clinical and pathologic manifestations in the brain, lungs, and spleen. The purpose of this study was to study pathologic and immunohistochemical findings in guinea pigs infected with NiV. Of 28 animals inoculated intraperitoneally, only 2 survived the infection, and most died between 4 and 8 days postinoculation (dpi). Viral antigen with minimal pathologic changes was first detected 2 dpi in lymph nodes and spleen. More severe changes were noted in these organs 4-8 dpi, where pathologic damage had a vasocentric distribution and viral antigen was abundant in vascular endothelium, tunica media, adventitia, as well as in macrophages lining sinuses. The urinary bladder, uterus, and ovaries were also affected with necrosis and acute inflammation. In these organs, immunohistochemical positive staining was intense in blood vessels, epithelial cells, and ovarian follicles. Approximately 50% of the animals that died or were euthanized in extremis had evidence of viral antigen and histopathologic changes in brain, especially involving meninges and ependymal cells, with lesser changes in the neural parenchyma. A unifying feature of the damage for all affected tissues was necrosis and inflammation of the vasculature, chiefly in arterioles, capillaries, and venules. Inoculation of guinea pigs intraperitoneally with NiV produces a disease with considerable resemblance to the disease in humans, but with reduced pulmonary involvement and marked infection of urinary bladder and the female reproductive tract.

Rib-muscle pedicle flap for the repair of congenital tracheal stenosis.

Congenital tracheal stenosis (CTS) is an uncommon congenital anomaly that presents early in life with symptoms of biphasic stridor. Most cases require surgical correction. Techniques have included dilation, resection of the involved segment, and tracheoplasty. Today pericardium and costal cartilage are the most frequently used materials for tracheoplasty, but patients still often encounter problems with the graft, with the procedure, or with late complications. This preliminary study was undertaken to determine the feasibility of a rib-intercostal muscle pedicle flap for the treatment of CTS. Tracheoplasties were performed on seven 3.5- to 5.5-kg piglets with a pedicled segment of the right fourth rib via a lateral thoracotomy incision. The method was found to be technically feasible, and pedicles of greater than 2.5 cm were easily developed. The repair provided good structural support and an airtight seal at high ventilator pressures. Histologic examination after 2 weeks showed the flap to be incorporating into the native trachea and to be without degenerative changes. This "vital" composite flap has several real and theoretic advantages over current methods of repair and may prove to be valuable in the treatment of CTS. The clinical application of this myo-osseous pedicle graft in the treatment of patients with stenoses not amenable to surgical resection and primary anastomosis should be explored.

Nefrectomía laparoscópica por hidronefrosis: presentación de 1 caso y revisión del tema / Laparoscopic nephrectomy for the treatment of hydronephrosis: case presentation and subject review

Se presenta 1 caso de reseccion completa de un riñon hidronefrotico gigante mediante acceso laparoscopico en una mujer de 28 años con una estenosis pieloureteral izquierda y atrofia renal severa. La evolucion posquirurgica fue excelente.

Parathyroid re-exploration.

The authors evaluated their experience with 27 patients who required parathyroid re-explorations. The initial exploration was unsuccessful in 20 patients: in 8 because of ectopic lesions, in 2 because of undetected supernumerary glands, and in 10 because of inadequate exploration of the neck. All of the patients with inadequate neck explorations were found to have eutopic disease. Seven patients required re-exploration because of recurrent disease. Localization studies were performed prior to re-explorative surgery in 26 of 27 patients, which resulted in successful placement in 21. Invasive procedures, selective vein catheterization, and/or arteriography were effective in 12 of 15 patients. Noninvasive procedures, including thallium-technetium scintigraphy, magnetic resonance imaging, computed tomography, and ultrasonography, were accurate in 14 of 21 patients. Twenty-three (85%) of 27 patients were cured, including 17 of 20 patients after an unsuccessful initial exploration and 6 of 7 patients with recurrent disease. Careful review of operative and pathology reports from the initial surgery was essential in determining the adequacy of the exploration, the presence of microscopic abnormalities, and the glands that were positively identified. Such analysis, in conjunction with noninvasive localization studies, will lead to successful re-exploration in the majority of cases.

Stercoraceous perforation of the right colon.

We have reported a case of stercoraceous perforation of the right colon with peritonitis. Stercoraceous perforation should be considered in patients with an acute condition of the abdomen, radiologic evidence of a perforated viscus, and a long-standing history of constipation. The condition is rare and has a high mortality. The treatment of choice is always surgical.