Estimation of Rabbit Pancreas Dispersion Between 400 and 1000 nm

Current biophotonics methods cover the entire optical spectrum from the deep ultraviolet to the terahertz. To optimize such methods for diagnostic and therapeutic applications, the need to obtain the wideband dispersion of tissues is high. The pancreas is a very important organ in the human body, since it produces insulin and its malfunction may induce diabetes. A reduced number of biophotonics publications regarding the pancreas is available, meaning that studies to determine its optical properties and their variation during optical clearing treatments are necessary. Considering this fact, we used the total internal reflection method to measure the refractive index of the rabbit pancreas for wavelengths between 400 and 850 nm. The experimental results allowed to calculate the pancreas dispersion with the Cauchy, Conrady and Cornu equations. It was observed that all those equations provided good data fitting in the spectral range of the measurements, but differences were observed outside these limits. Considering the wavelength of 633 nm, the mean value from the three dispersions was 1.3521, while the one published for porcine pancreas is 1.3517. The dispersion calculated with the Conrady equation does not present a fast decreasing behavior for shorter wavelengths as the ones calculated with the Cauchy and Cornu equations, but comparing these curves with a dispersion for a tissue-like material, all seem to have good agreement.

Experimental Model of Pancreonecrosis Induced by Auto-bile Injection

AIM: The aim of the study is to create an easily reproducible experimental model of pancreonecrosis with the least aggressive technique of the operation. METHODS: Twenty-two outbred rabbits of comparable weight and age were included in the study. The animals were removed from the experiment 12, 24, and 48 h after the injection of auto-bile into the parenchyma of the pancreas. RESULTS: After completion of the experiment, rabbit pancreas was extracted, macroscopic and microscopic description was given. CONCLUSION: According to the results of the study, the proposed model is considered as consistent for reproducing pancreonecrosis in an experiment with less aggressive surgical technique.

Development of the Rabbit Pancreas with Particular Regard to the Argyrophilic Cells

The aim of the study was the description of the prenatal development of rabbit pancreas, cell modifications, and changes in their volume and mitotic activity. Immunohistochemical, light and electron microscopic procedures were employed. Stereological methods were used for estimation of cellular and nuclear volumes. hits on epithelial cells, tubular lumens, and endocrine progenitor cells were counted by systematic field sampling using test grid. Number of mitoses was registered in various cellular types after colchicine treatment. Data obtained were converted to 1 mm3 tissue. First granules were observed in cells on day 10 and 18 hours, however two different granular types are distinguishable by electron microscopy only on day 15, when insulin and glucagon can be detected immunohistochemically. Cellular volume increased remarkably in harmony with findings of granules in serous cells. Number of epithelial cells increased also exponentially. The increase was more rapid between days 13 and 15, later it appeared exponential. Value of mitotic index and length of cell cycle did not change considerably between days 15 and 24. Mitoses were observed in ductal, exocrine, as well as endocrine cells. The dividing endocrine cells were those that contained fine dense granules (progenitor cells). The sub-population of progenitor cells is able to divide, however, this source of cells appears insufficient for exponential growth. Results after colchicine treatment show the increase of cell population but the life-span and a period necessary for volume multiplication vary. Mitoses decrease in both sub-populations during the prenatal period. The progenitor cells arise probably by differentiation from the ducts, because their number increases proportionally to the main cell population.