Frank Reilly

Hepatic microvascular regulatory mechanisms. I. Adrenergic mechanisms

Abstract The neural and pharmacologic responses of the hepatic microvasculature were evaluated in Sprague-Dawley rats anesthetized with urethane or pentobarbital. Various concentrations of several potential vasoactive substances alone or in combination with appropriate blocking agents were administered topically to the livers of these rats while changes in the microvasculature were measured using in vivo microscopic methods. The results provided logarithmic dose-response data for these substances in order to establish the relative sensitivity of various segments of the microvasculature and demonstrated adrenergic receptors in the microvasculature. Alpha receptors were demonstrated on all segments of the microvasculature while beta receptors (beta2) were isolated on portal venules and sinusoids. In the sinusoids, the lining cells were the site responsive to adrenergic substances. These cells appear to be the primary site for locally regulating flow through the sinusoids. Electrical stimulation of the celiac ganglion and the nerves associated with the celiac artery elicited alpha-mediated constriction of portal venules, hepatic arterioles, and sinusoids while stimulation of the nerves associated with the portal vein elicited responses of a lesser magnitude in these vessels. The constriction of hepatic arterioles was of a much larger magnitude than that of portal venules. All of the microvascular responses to neural stimulation were antagonized by alpha-receptor blockade.

The Fluorescent Staining of Heparin in Mast Cells Using Berberine Sulfate: Compatibility with Paraformaldehyde or o-Phthalaldehyde Induced Fluorescence and Metachromasia

The berberine sulfate technique of Enerback (1974) for the demonstration of heparin was applied to freeze-dried or routinely fixed paraffin embedded sections from various tissues. Sections from tissue which had been freeze-dried were deparaffinized, fixed in Carnoy Formula A for 15 minutes, rinsed in ethanol, hydrated, stained for 20 minutes in a 0.02% aqueous solution of berberine sulfate at a pH of 1, 2, 3, 4, 5 or 6 and rinsed in distilled water at a pH corresponding to the staining solutions. Carnoy Formula A or formalin-fixed tissues were routinely processed and sections were stained as above. Also, sections of freeze-dried tissues which had been deparaffinized and treated with paraformaldehyde or o-phthalaldehyde were hydrated to quench the fluorescence due to serotonin or histamine and restained with aqueous solutions of berberine sulfate (pH 1—6). In sections of tissue at a pH above 4, yellow fluorescence was produced by berberine sulfate in both cartilage and mast cells while in those treated at ...

Identification of genes induced by rapid intraoperative tissue expansion in mouse skin

Abstract. A method of rapid skin stretching, i.e. hemispherical load cycling with an inflated subcutaneous silicone balloon (Rapid Intraoperative Tissue Expansion or RITE), permits the surgeon to rapidly elongate skin and create a flap of greater length for reconstructive plastic surgery. We have previously developed an experimental mouse model to evaluate RITE, and have shown that rapid stretching prevents ischemia and significantly reduces necrosis. Although the advantages of RITE have been demonstrated both clinically and experimentally, the cellular and molecular mechanisms underlying these benefits were unknown. In the study reported here, we used differential display reverse transcription polymerase chain reaction to identify genes that are specifically induced by RITE. Among four differential gene fragments, the expression of one was confirmed by Northern blot hybridization. The cDNA fragment was extended and the resultant sequence analyzed to reveal induction of truncated long interspersed nucleotide element 1 (LINE-1 or L1). Truncated L1 elements are located inside introns of many genes and among these genes myotubularin and insulin I are known to regulate cell growth. Northern hybridization using specific cDNA probes for myotubularin and insulin I demonstrated that it also was induced by RITE. This is the first reported study to show that L1, myotubularin and insulin I are responsive to rapid hemispherical and not rapid linear stretch.

Elevated Blood Glucose after Compound 48/80 Treatment Is Not Related to Hepatic Mast Cell Degranulation in Rats

Abstract Blood glucose, hepatic glycogen, and the histological integrity of hepatic mast cells, were evaluated in anesthetized rats receiving iv injections of 0.125 mg/kg body weight compound 48/80 (a mast cell degranulator) and/or of 0.001 to 10.0 mg/kg body weight lodoxamide tromethamine (an inhibitor of mast cell degranulation). A nonglucogenic dose of lodoxamide, 0.001 mg/kg body weight, prevented dissipation of histochemically demonstrable fluorescence in mast cells (degranulation) without inhibiting compound 48/80-induced hyperglycemia and hepatic glycogenosis. These results suggest that this glucotropic response is independent of compound 48/80-evoked release of mediators such as serotonin from mast cells.