Dynamic erectile responses of a novel penile organ model utilizing two photon excitation microscopy (TPEM)†

Male penis is required to become erect during copulation. In the upper (dorsal) part of penis, the erectile tissue termed corpus cavernosum (CC) plays fundamental roles for erection by regulating the inner blood flow. When blood flows into the CC, the microvascular complex termed sinusoidal space is reported to expand during erection. A novel in vitro explant system to analyze the dynamic erectile responses during contraction/relaxation is established. The current data show regulatory contraction/relaxation processes induced by phenylephrine (PE) and nitric oxide (NO) donor mimicking dynamic erectile responses by in vitro CC explants. Two photon excitation microscopy (TPEM) observation shows the synchronous movement of sinusoidal space and the entire CC. By taking advantages of the CC explant system, tadalafil (cialis) was shown to increase sinusoidal relaxation. Histopathological changes have been generally reported associating with erection in several pathological conditions. Various stressed statuses have been suggested to occur in the erectile responses by previous studies. The current CC explant model enables to analyze such conditions through directly manipulating CC in the repeated contraction/relaxation processes. Expression of oxidative stress marker and contraction related genes, Hif1a, Gpx1, RhoA, Rock was significantly increased in such repeated contraction/relaxation. Altogether, it is suggested that the system is valuable for analyzing structural changes and physiological responses to several regulators in the field of penile medicine.

A Mathematical Model of Blood Circulation in the Liver Lobule

The liver has a specialized circulation. It is supplied by two main vessels: the hepatic portal vein, carrying nutrient-rich deoxygenated blood, and the hepatic artery, carrying oxygenated blood. The hepatic portal vein supplies up to 80% of the blood. Within the liver, both the portal vein and the hepatic artery undergo a series of successive bifurcations, which end at the portal tracts. Each portal tract contains three vessels: a portal vein, an artery and a bile duct. Blood drains out from the portal tracts into the sinusoidal space and from there into the central veins. The central veins, after a series of converging bifurcations, end at the hepatic veins, which carry blood out of the liver. The sinusoidal space consists of a network of tortuous, interconnected channels called sinusoids. One of the most common and widely accepted descriptions of the primitive units of the liver is the “classic lobule”. A diagram of an idealized arrangement of liver lobules is shown in Figure 1. Each lobule has the shape of a hexagonal prism with a portal tract running along each of the parallel edges and a central vein on the central axis. The remainder of the space is made up of sinusoids.

REVERSAL BY ADENINE OF THE ETHIONINE-INDUCED LIPID ACCUMULATION IN THE ENDOPLASMIC RETICULUM OF THE RAT LIVER

Within 3.5 to 4 hours after thionine administration, numerous small osmiophilic bodies, liposomes, appear in the endoplasmic reticulum of the liver cells. By fusion, the liposomes lead to the formation of larger collections of fat, giant liposomes. Adenine administration to ethionine-treated rats removes the liposomes from the hepatocytes and causes the transitory appearance of osmiophilic droplets in the sinusoidal space of Disse. The characteristic disaggregation of hepatic polysomes seen in the liver after ethionine administration is corrected by the injection of adenine.