Modification of an Experimental Model GDI Tumbling Flow by Direct Injection

Deoxynivalenol (DON), also known as vomitoxin, is a mycotoxin that can cause antifeeding and vomiting in animals. However, the mechanism of DON inducing anorexia is complicated. Studies have shown that intestinal hormones play a significant part in the anorexia caused by DON. We adopted the “modeling of acute antifeeding in mice” as the basic experimental model, and used two methods of gavage and intraperitoneal injection to explore the effect of intestinal hormones on the antifeedant response induced by DON in mice. We found that 1 and 2.5 mg/kg·bw of DON can acutely induce anorexia and increase the plasma intestinal hormones CCK, PYY, GIP, and GLP-1 in mice within 3 h. Direct injection of exogenous intestinal hormones CCK, PYY, GIP, and GLP-1 can trigger anorexia behavior in mice. Furthermore, the PYY receptor antagonist JNJ-31020028, GLP-1 receptor antagonist Exendin(9-39), CCK receptor antagonist Proglumide, GIP receptor antagonist GIP(3-30)NH2 attenuated both intestinal hormone and DON-induced anorectic responses. These results indicate that intestinal hormones play a critical role in the anorexia response induced by DON.

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Intraoperative study of the functional perforasome - an experimental model

Medicine and Pharmacy Reports ◽

10.15386/mpr-1896 ◽

2021 ◽

Author(s):

Maria-Eliza Nedu ◽

Alexandru Dan Valentin Georgescu

Keyword(s):

Methylene Blue ◽

Experimental Model ◽

Direct Injection ◽

Fluorescent Dye ◽

Medial Branch ◽

Perforator Flaps ◽

Epigastric Artery ◽

Blue Solution ◽

Minimal Concentration

Background and aims. The aim of this study is to find the most suitable protocol based on an animal experimental model, through the use of a fluorescent dye, determining also its minimal concentration needed to stain the skin after arterial injection, in order to be evidence the functional perforasome by visual examination. Methods. Methylene blue solution was used in order to determine the territory vascularized by one perforator on fresh cadavers in many studies which introduced, as a final result, the concept of perforasome. One of the most frequent complications of perforator flaps is partial flap necrosis which could be avoided by correctly assessing pre-operatively the functional perforasome surface. Two groups of seven rats were used in order to establish a proper surgical protocol to evaluate the functional perforasome in vivo by injecting the dye. Also, the minimal concentration for methylene blue was experimentally determined. Results. The direct injection into the femoral artery of the proper concentration of dye, 1mM for methylene blue and the clamping of all the branches except the medial branch of the superficial epigastric artery is a reliable model to study the functional perforasome. Conclusions. Our study demonstrates that the intraoperative assessment with fluorescent dye of the functional perforasome by intra-arterial injection of methylene blue is an easy, affordable and very efficient method to reduce the number of partial necrosis of the perforator flaps.

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Ultrastructure of melanocyte-keratinocyte interactions and pigment transfer in vitro

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084120 ◽

1978 ◽

Vol 36 (2) ◽

pp. 650-651

Author(s):

Raul I. Garcia ◽

Evelyn A. Flynn ◽

George Szabo

Keyword(s):

Direct Injection ◽

Skin Pigmentation ◽

Freeze Fracture ◽

Pigment Granule ◽

Time Lapse ◽

Ultrastructural Level ◽

Lanthanum Tracer ◽

A Cell

Skin pigmentation in mammals involves the interaction of epidermal melanocytes and keratinocytes in the structural and functional unit known as the Epidermal Melanin Unit. Melanocytes(M) synthesize melanin within specialized membrane-bound organelles, the melanosome or pigment granule. These are subsequently transferred by way of M dendrites to keratinocytes(K) by a mechanism still to be clearly defined. Three different, though not necessarily mutually exclusive, mechanisms of melanosome transfer have been proposed: cytophagocytosis by K of M dendrite tips containing melanosomes, direct injection of melanosomes into the K cytoplasm through a cell-to-cell pore or communicating channel formed by localized fusion of M and K cell membranes, release of melanosomes into the extracellular space(ECS) by exocytosis followed by K uptake using conventional phagocytosis. Variability in methods of transfer has been noted both in vivo and in vitro and there is evidence in support of each transfer mechanism. We Have previously studied M-K interactions in vitro using time-lapse cinemicrography and in vivo at the ultrastructural level using lanthanum tracer and freeze-fracture.

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Ultrastructural Alterations in Sinusoidal Endothelial Fenestrae as a Result of Hypoxia

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100090828 ◽

1976 ◽

Vol 34 ◽

pp. 168-169

Author(s):

Waykin Nopanitaya ◽

Raeford E. Brown ◽

Joe W. Grisham ◽

Johnny L. Carson

Keyword(s):

Endothelial Cells ◽

Experimental Model ◽

Hepatic Lobule ◽

Ultrastructural Alterations ◽

Large Type ◽

Sinusoidal Endothelial Fenestrae ◽

General Size ◽

Sem Studies

Mammalian endothelial cells lining hepatic sinusoids have been found to be widely fenestrated. Previous SEM studies (1,2) have noted two general size catagories of fenestrations; large fenestrae were distributed randomly while the small type occurred in groups. These investigations also reported that large fenestrae were more numerous and larger in the endothelial cells at the afferent ends of sinusoids or around the portal areas, whereas small fenestrae were more numerous around the centrilobular portion of the hepatic lobule. It has been further suggested that under some physiologic conditions small fenestrae could fuse and subsequently become the large type, but this is, as yet, unproven.We have used a reproducible experimental model of hypoxia to study the ultrastructural alterations in sinusoidal endothelial fenestrations in order to investigate the origin of occurrence of large fenestrae.

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