A novel method for preparation of animal models of liver damage: liver targeting of carbon tetrachloride in rats

Animal models prepared by treatment with toxic compounds such as a carbon tetrachloride have been used to examine drug disposition in hepatic diseases. However, it is possible that these compounds accumulate and cause damage to other organs as they are administered systemically. In this study, we used the liver surface application technique to deliver a toxic compound to the liver to prepare an appropriate animal model in which only the liver is significantly damaged. To restrict the absorption area in the liver, a cylindrical diffusion cell was attached to the liver surface of male Wistar rats. Twenty-four hours after direct addition of carbon tetrachloride to the diffusion cell, plasma levels of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT), and hepatic malondialdehyde (MDA) concentration were increased, while there were no changes in plasma creatinine or renal MDA level. On the other hand, not only GOT, GPT and hepatic MDA, but also creatinine and renal MDA levels were markedly increased by p.o. and i.p. administration of carbon tetrachloride, suggesting renal damage. These results indicated that the animal models of liver damage prepared by utilizing drug delivery techniques to accumulate toxic compounds in the liver would enable us to investigate the precise effects of hepatic disorder on drug disposition.     

Frequency of common bile duct motion artifacts caused by inferior vena cava pulsation on magnetic resonance cholangiopancreatography.

PURPOSE: We assessed the frequency of common bile duct (CBD) motion artifacts caused by inferior vena cava (IVC) pulsation on magnetic resonance cholangiopancreatography (MRCP). METHODS: We retrospectively evaluated CBD motion artifacts in 4 MRCP sequences from each of 115 consecutive patients. RESULTS: We observed 37 (32.2%) ghost artifacts at the ventral and dorsal aspects of the CBD on transaxial, half-Fourier acquisition single-shot turbo spin-echo (HASTE-ax) images; no such artifacts were observed on transaxial T(2)-weighted turbo spin-echo images. In 10 patients, we observed 9 (7.8%) pseudo-defects of the CBD on 3-dimensional T(2)-weighted turbo spin-echo with navigator-triggered prospective acquisition correction technique MRCP and 6 (5.2%) pseudo-defects on single-shot rapid acquisition with relaxation enhancement MRCP. Pseudo-defects were significantly more frequent in patients with ghost artifacts than without (9 of 37 [24.3%] versus one of 78 [1.3%]; P<0.01, McNemar test). CONCLUSION: Although uncommon, pseudo-defects of the CBD caused by IVC pulsation are observed on MRCP. MRCP interpretation that includes comparison with HASTE-ax images can diminish the potential misinterpretation of such CBD motion artifact as bile duct tumor or biliary stone.     

Photocrosslinking behavior of poly(vinyl alcohol)s with pendent styrylpyridinium or styrylquinolinium groups

Poly(vinyl alcohols) (PVA's) with pendent styrylpyridinium (SbQ), styrylquinolinium (QQ), or oxystyrylquinolinium (OQQ) exhibit anomalously high photosensitivity, even if the content of photosensitive groups is very low. This phenomenon was studied by measuring the sensitivity to crosslinking quantitatively using monochromatic light. When the content of SbQ or OQQ exceeds ca. 1 mol-%, the photoinduced gelation behaviour was found to be in the line with Charlesby's equation, suggesting that the absorbed light energy leads specifically to interamacromolecular photodimerization of SbQ or OQQ. Under these circumstances, the quantum efficiency for the photodimerization of SbQ and OQQ was estimated to be in the ranges of 0,31–0,37 and 0,10–0,17, respectively. The applicability of PVA-SbQ to water-developable photoresists for microfabrications is discussed. The sensitivity characteristics of PVA having OQQ and analogous groups is also mentioned in view of the application to Ar laser resists.