Among the known causes for the occurrence of hepatocellular carcinoma (HCC), chemical carcinogens, chronic alcoholic intake and hepatitis B virus (HBV), especially in Asia, has been emphasized. HBV has been industriously studied and many queries about the relationship between HBV infection and hepatocarcinogenesis have been clarified. Recent descovery of hepatitis C virus (HCV) revealed that there may be the participation of this virus in hepatocarcinogenesis. However, a precise mechanism in such a viral infection has not been known. Host immunological defence mechanisms including the role of cytokines should be also taken into consideration. Cellular gene abnormalities have been noted in the late period of cancer cell progression. The technical development in the clinically available diagnostic procedures have enabled us to detect early phase of HCC. Some new concepts in the pathological diagnosis of precancerous lesions of HCC and also early HCC have been reported recently. We gave an outline of the recent advances and references in the study of HCC.
To investigate roles of prostaglandins in the regulation of cerebral blood flow, we compared effects of indomethacin, a cyclooxygenase inhibitor, on the cerebrovascular CO2 responsiveness with those on the cerebrovascular dilatory action of diltiazem, a Ca2+-channel blocker. Fifteen adult cats were used. The cerebral tissue oxygen tension, carbon dioxide tension, pH and blood pressure were measured continuously. Indomethacin (1mg/kg) was infused into the carotid artery. In 8 cats, 3min inhalation of 5% CO2 in air was performed before and after the indomethacin infusion. In 7 cats, diltiazem (100μg/kg) was infused into the carotid artery for 3min before and after the indomethacin infusion. The cerebrovascular CO2 responsiveness was significantly decreased (p<0.05) after the administration of indomethacin. On the other hand, the cerebrovascular dilatation induced by the Ca2+-channel blocker was significantly increased (p<0.05) after the administration of indomethacin. It is concluded that the products of cyclooxygenase system are involved in the cerebrovascular responsiveness both to CO2 and to Ca2+-channel blocker, but action mechanisms of prostaglandins may be different, that is, prostaglandians may enhanced cerebrovascular responsiveness to CO2 but diminish it to Ca2+-channel blocker.
Contrast sensitivity and glare sensitivity are often abnormal in cataract patients. However, despite significant subjective complains, relatively good visual acuities are obtained with high-contrast optotypes. Using Variable Contrast Visual Acuity Charts with contrast levels of 90, 15, and 2.5% and reverse polarity of 90% contrast, contrast visual acuities were measured in 24 normal subjects (40 eyes) (Landolt visual acuity ≥1.0); 28 cataract patients (40 eyes)(Landolt visual acuity ≥0.6); and 75 patients (100 eyes) [best-corrected Landolt visual acuity ≥0.8 after intraocular lens (IOL) implantation]. The cataract group experienced the greatest decrease of contrast visual acuity when the high-contrast chart (chart 1) measurements were compared with the 15% (0.71 vs 0.52-0.64 octave) and the 2.5% contrast charts (1.75 vs 1.21-1.48 octaves), followed by the IOL group, and the normal subjects. In the cataract group, 23/40 eyes (57.5%) showed better contrast visual acuity with chart 4 than chart 1. Although much less in frequency, 28/100 (28%) eyes with IOLs also showed better contrast acuity measured with chart 4 than with chart 1. In addition to high-contrast optotypes, acuity measurements using intermediate-to low-contrast optotypes, combined with the reverse polarity chart, seem effective to analyze visual disabilities caused by early cataract. The pattern of the contrast acuity profile of the IOL patients was comparable to normal subjects, but the glare effect still existed after IOL implantation, though to a lesser degree than in cataractous eyes.
We have used overcrowding stress to study the pathogenesis of depression and the action of antidepressant drugs. In the present study, the influence of overcrowding on behavior was assessed by the forced swimming test. All the stressed rats revealed highly characteristic head twitching movement, which was not inhibited by repeated administration of diazepam and haloperidol, but was markedly suppressed by repeated administration of desipramine and mianserine. A significant positive correlation in the number of twitching episodes in each stressed rat between the first and second forced swimming test was seen. These findings support the use of overcrowding of rats as a stressor in the animal depression model because it fulfills the criteria of the model; face validity, construct validity and predictive validity. We propose the adoption of “swimming head twitching” as a new marker in the animal model of depression.