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Background: To assess the effects of alcohol on the histological changes in chronic hepatitis type C, we performed histopathological examination on liver biopsy specimens by using a semiquantitative method., Methods: Subjects were 91 patients with chronic hepatitis type C and 32 with alcoholic liver disease. The patients with chronic hepatitis type C were classified into three groups according to the total amount of alcohol intake: nondrinkers, moderate drinkers, and heavy drinkers. For each patient, we evaluated pathological changes of several items and awarded scores from 0 to 2 points, with severe to moderate scoring 2 points, mild 1, and negative 0; the total score was then compared between groups. The evaluated histological changes included virus-related histological changes (V1, inflammatory cell infiltration; V2, lymphoid follicle formation; and V3, bile duct damage) and alcohol-related changes (A1, perivenular fibrosis; A2, stellate/pericellular fibrosis; and A3, fatty change)., Results: The total scores of the hepatitis C virus-related histological changes were significantly lower in patients with alcoholic liver disease (ALD group) (p < 0.05). However, we found no significant difference between the different alcohol intake groups. The total score for alcohol-related histological changes significantly increased in line with increases in total alcoholic intake regardless of the presence or absence of hepatitis type C virus infection (p < 0.05)., Conclusions: The results suggest that both alcoholic-related liver damage and virus-related liver damage have specific features; in a addition, alcohol was found to have little effect on the histological liver damage observed in chronic hepatitis type C.

Background: Our study was undertaken to check the discordance between findings from 99mTc-Sn colloidal reticuloendothelial scintigraphy (RESS) and 99mTc-GSA asialo-scintigraphy (GSA, a technique for evaluation of liver parenchymal cell density and function) and to analyze the discordance in relation to functional disturbances. We compared data between patients with alcoholic liver diseases (ALD) and patients with viral liver diseases (VLD)., Methods: The subjects of this study were 40 patients with chronic liver disease (17 with ALD and 23 with VLD). We used the liver uptake ratio of the tracer of the Sn colloid (SnL15, %), the liver uptake rate (GSAL15, %), and the Rmax (an indicator of total liver receptors) as indices of liver scans., Results: GSAL15 was sometimes nondiscordant from SnL15. The patients were divided into two groups: the nondiscordant group (26 cases where the balance/sum of the two variables was <25%) and the discordant group (14 cases where the balance/sum was > or =25%). SnL15 was 41.6 +/- 16.2% in the nondiscordant group and 42.7 +/- 16.3% in the discordant group (p = 0.80). GSAL15 was 34.3 +/- 12.1% in the nondiscordant group and 21.5 +/- 8.1% in the discordant group (p = 0.001). Rmax was 0.33 +/- 0.17 in the nondiscordant group and 0.113 +/- 0.008 in the discordant group (p = 0.002). Thus, the SnL15, as determined by RESS, did not differ significantly between the nondiscordant and discordant groups, whereas GSAL15 was significantly unfavorable in the discordant group as compared with the nondiscordant group. SnL15 as determined by RESS did not differ significantly between the ALD group (40.4 +/- 18.7%) and the VLD group (43.5 +/- 15.0%) (p = 0.59), whereas Rmax as determined by GSA was significantly improved in the ALD group (0.34 +/- 0.20) compared with the VLD group (0.20 +/- 0.4) (p = 0.02)., Conclusions: Liver cell function was lower in cases that showed discordance between liver cell function and reticuloendothelial function compared with cases without such discordance, although reticuloendothelial function did not differ between discordant and nondiscordant groups. Liver cell function was better in cases of ALD than in cases of VLD, whereas reticuloendothelial function did not differ between the ALD group and the VLD group.

A mechanism by which the Ras-mitogen-activated protein kinase (MAPK) signaling pathway mediates growth factor-dependent cell survival was characterized. The MAPK-activated kinases, the Rsks, catalyzed the phosphorylation of the pro-apoptotic protein BAD at serine 112 both in vitro and in vivo. The Rsk-induced phosphorylation of BAD at serine 112 suppressed BAD-mediated apoptosis in neurons. Rsks also are known to phosphorylate the transcription factor CREB (cAMP response element-binding protein) at serine 133. Activated CREB promoted cell survival, and inhibition of CREB phosphorylation at serine 133 triggered apoptosis. These findings suggest that the MAPK signaling pathway promotes cell survival by a dual mechanism comprising the posttranslational modification and inactivation of a component of the cell death machinery and the increased transcription of pro-survival genes.

The apoptosis-resistant phenotype of cloned high-metastatic A11 and low-metastatic P29 cells isolated from Lewis lung carcinoma was compared. The results showed that A11 cells were more resistant to apoptosis induced by microenvironmental stresses such as serum starvation, glucose deprivation and hypoxia than P29 cells as judged by viability, DNA laddering, and chromatin condensation and fragmentation. Both cell lines were insensitive to tumor necrosis factor-alpha-mediated apoptosis. P29 cells expressed a much higher level of Fas antigen on the cell surface than A11 cells. However, both cell lines were also insensitive to Fas-mediated apoptosis. The apoptosis resistant phenotype of A11 cells was associated with the expression level of caspase-3, but not with those of Bcl-2, Bcl-X(L) Bax, p27Kip1 and DAP kinase. There was no difference between A11 and P29 cells in the expression of E-cadherin, the adhesiveness to the extracellular matrix components or the expression levels of metastasis-associated genes such as c-Ha-ras, c-jun, p53 and nm23. Furthermore, A11 cells exhibited lower motile and invasive abilities than P29 cells. These results suggest that the apoptosis-resistant phenotype is an important factor for determining the metastatic ability of A11 cells. Supporting this, P29 cells became more apoptosis-resistant after treatment of the cells with dimethylsulfoxide which is reported to enhance the experimental metastatic potential of the cells.

The TTV DNA were examined in patients with chronic liver diseases B (n = 35), C (n = 44) and non-B non-C (n = 19). The clinical background, liver function and liver histological finding were compared in patients with or without TTV infection. The prevalence of TTV in patients with chronic liver diseases B, C and non-B non-C were 37.1%, 27.3% and 52.6%, respectively. There was no significant difference in liver function test between TTV positive and negative patients with chronic liver diseases B and C. The gamma-GTP level of TTV positive patients were significantly higher than that of TTV negative patients with chronic liver diseases non-B non-C. The histological findings were similar between patients with or without TTV infection. We concluded that even though the co-infection of TTV in patients with chronic liver diseases B and C was high, TTV does not act as a liver injury agent. The relationship between TTV and non-B non-C chronic liver diseases is unclear.

Background/aims: An unenveloped single-stranded DNA virus (TTV) has been reported in association with elevated transaminase levels in patients with posttransfusion hepatitis and in those with acute or chronic liver disease of unknown etiology. To further evaluate the association of TTV with liver disease, TTV DNA was searched for in patients with acute or chronic liver disease of various etiologies., Methods: TTV DNA was determined by polymerase chain reaction with hemi-nested primers in 64 patients with acute or chronic liver disease of unknown etiology and in 100 with acute or chronic liver disease positive for antibody to hepatitis C virus (HCV) as well as HCV RNA., Results: TTV DNA was detected in two of the seven (29%) patients with acute hepatitis of unknown etiology, but in none of the four patients with acute HCV-associated hepatitis. It was detected in 27 of the 57 (47%) patients with chronic liver disease of unknown etiology at a frequency significantly higher (p<0.001) than that in 17 of the 96 (18%) patients with chronic HCV-associated liver disease. By contrast, RNA of hepatitis G virus was detected in none of the patients with acute hepatitis, and only in one of the 57 (2%) patients with chronic liver disease of unknown etiology as well as in six of the 96 (6%) patients with chronic HCV-associated liver disease., Conclusions: Based on the obtained results, TTV has a role in the development of acute and chronic liver disease of unknown etiology.

The NMDA (N-methyl-D-aspartate) subclass of glutamate receptor is essential for the synaptic plasticity thought to underlie learning and memory and for synaptic refinement during development. It is currently believed that the NMDA receptor (NMDAR) is a heteromultimeric channel comprising the ubiquitous NR1 subunit and at least one regionally localized NR2 subunit. Here we report the characterization of a regulatory NMDAR subunit, NR3A (formerly termed NMDAR-L or chi-1), which is expressed primarily during brain development. NR3A co-immunoprecipitates with receptor subunits NR1 and NR2 in cerebrocortical extracts. In single-channel recordings from Xenopus oocytes, addition of NR3A to NR1 and NR2 leads to the appearance of a smaller unitary conductance. Genetic knockout of NR3A in mice results in enhanced NMDA responses and increased dendritic spines in early postnatal cerebrocortical neurons. These data suggest that NR3A is involved in the development of synaptic elements by modulating NMDAR activity.

We constructed a new fluorescein fundus angiography system using a speedy and sensitive fundus camera and an argon laser apparatus as the illumination source. The system consists of a fluorescein fundus camera, a high-speed camera, a digital recorder, an argon laser apparatus, and a cathode ray tube(CRT)monitor. The frame speed was 200 frames/s. It was possible to record high speed fluorescein angiography with lower illumination by using an argon laser as the illumination source. This system allowed us to measure the rate of blood flow in the retinal vessels because it easily detected the dye front in the retinal vessels.

Excitatory amino acid (EAA) receptors play an important role in neuronal cell death in acute cerebral ischemia. Blocking the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) subtype of EAA receptor has been shown to reduce cell death in global cerebral ischemia. However their role in focal stroke, although suggestive, has remained more contentious. To clarify this issue, we generated transgenic mice overexpressing the AMPA receptor (AMPAR) subunit GluR2-flip which would increase AMPAR-mediated currents. Excitatory neurons in these transgenic mice are thus predicted to be more susceptible than wild-type neurons to EAA (glutamate)-induced excitotoxic damage. Consistent with this prediction, cultured neurons from transgenic mice had a lower LD50 for exposure to glutamate (10(-3)-10(-5) M for 5 min) compared to wild-type neurons. Moreover, transgenic mice subjected to permanent focal ischemia of the middle cerebral artery (MCA) using the intralumenal filament model sustained larger infarctions compared to wild-type controls. Hence we have developed a genetic mouse model that demonstrates the crucial role of AMPAR containing GluR2-flip in the pathogenesis of focal hypoxic-ischemic neuronal cell death. This model will be a valuable tool in elucidating molecular mechanisms of glutamate excitotoxicity and evaluating the efficacy of glutamate receptor antagonists in attenuating post-ischemic neuronal cell death.

The evidence for the role of ascorbic acid in gene expression or protein synthesis in vivo is limited. To investigate this role of ascorbic acid, we surveyed proteins whose tissue levels are changed by ascorbic acid deficiency by using ODS rats with a hereditary defect in ascorbic acid biosynthesis. Male ODS rats (7 wk old, body weight approximately 130 g) were fed a basal diet containing ascorbic acid (300 mg/kg diet) or an ascorbic acid-free diet for 14 d. Ascorbic acid deficiency decreased a renal protein with an apparent molecular mass of 17 kDa. The amino-terminal amino acid sequence of 16 residues of this 17-kDa protein was identical to a kidney fatty acid-binding protein known to be generated by proteolytic degradation of alpha2u-globulin, a major urinary protein of adult male rats. alpha2u-Globulin is synthesized in liver, secreted into blood and excreted into urine, but partially reabsorbed by renal proximal tubules. It exists in kidney in a proteolytically modified form. Ascorbic acid deficiency lowered the renal level of kidney fatty acid-binding protein to 53% (P < 0.05) and lowered the serum level of alpha2u-globulin to 52% (P < 0.05) of the level of the control group, but did not affect the amount of alpha2u-globulin excreted into urine. The hepatic level of alpha2u-globulin mRNA of the ascorbic acid-deficient rats was significantly lower (30%) than that of the control rats. These results suggest that in male ODS rats, ascorbic acid deficiency decreases the renal level of kidney fatty acid-binding protein by lowering alpha2u-globulin gene expression in liver.

The content of microsomal protein is the same in both kidneys and small intestine, corresponding to 57% of the control value expressed as 100% in the untreated liver. The contents of P450 and cytochrome b(5), and the activity of NADPH-cytochrome c reductase in the kidney were higher than those in the small intestine, which were 17%, 22% and 41% of controls, respectively, in the former and 5%, 11% and 22% of controls in the latter. As compared with similar measurements made in the liver, the activities of substrate-metabolizing enzymes in these extrahepatic organs were very low. The activities of renal aniline hydroxylase, aminopyrine N-demethylase, 7-ethoxycoumarin O-deethylase, 7-methoxycoumarin O-demethylase and benzo(a)pyrene hydroxylase were 6%, 5%, 3%, 0.6% and 0.2% of controls, respectively. The activities of these enzymes in the small intestine were lower than those in the kidney or below the limits of detection. These results suggested that isoforms or their contents of P450 responsible for these substrate biotransformations are different among liver, kidneys and small intestine. Meantime, this study showed similar significant inductions by phenobarbital and rifampin of small intestinal and hepatic microsomal drug-metabolizing enzymes. In contrast, neither phenobarbital nor rifampin was capable of increasing renal microsomal enzymes, with the exception of benzo(a)pyrene hydroxylase which was induced by rifampin. These findings indicated that both liver and small intestine, but not kidneys contain the same phenobarbital- and rifampin-inducible P450 isoforms, cytochrome b(5) and NADPH-cytochrome c reductase. In addition, CCl(4) could be bioactivated by CYP2E1 to free radicals in the kidney which caused destruction of microsomal enzymes. In mice pretreated with phenobarbital, CCl(4) also attenuated the increase in content of P450 in the small intestine, which appeared to be a result of induction by phenobarbital of CYP2E1.

Rifampicin conferred significant protection against carbon tetrachloride (CCl4)-induced liver injury. Serum alanine transaminase (ALT) and aspartate transaminase (AST) activities were not markedly altered and only hepatocellular fatty degeneration was found in mice pretreated with rifampicin (200 mg/kg), whereas severe centrilobular necrosis was observed and serum ALT and AST activities were as high as 281 and 271 I.U./l, respectively, in the control group following administration of CCl4 (400 microliters/kg). The contents and activities of microsomal drug-metabolizing enzymes in rifampicin-pretreated animals were also much higher than those of the controls. CCl4-mediated malondialdehyde (MDA) formation was increased in rifampicin-treated liver microsomes, demonstrating that rifampicin was capable of increasing the NADPH-dependent metabolism of CCl4 catalyzed by P-450 2E1 to produce free radicals. However, MDA formation was obviously depressed by rifampicin at varying concentrations from 2 to 32 x 10(-6) M in an in vitro cytochrome P-450 (P-450) enzyme system. On the other hand, NADPH oxidation in the metabolism of CCl4 and aniline hydroxylation were not suppressed in the presence of rifampicin in this systems, suggesting that rifampicin did not influence the biotransformation of CCl4 by P-450 2E1 in vitro. Therefore, the protective effect of rifampicin against CCl4 hepatotoxicity appeared to result from the direct inhibition of lipid peroxidation generated by CCl4-derived free radicals.

Fluorescein angiographic examination may be prevented by vitreous hemorrhage or opacities in vitreoretinal diseases before vitrectomy. We performed intraoperative fluorescein angiography for such cases, using a conventional light source and an ultrasensitive video camera equipped with a silicone intensifier target tube to avoid retinal phototoxicity. Intraoperative fluorescein angiograms allowed evaluation of neovascular vessels, proliferative tissues, and avascular areas associated with diabetic retinopathy. Indentation of the pars plicata enabled us to also record fluorescein images of the area. This device may aid intraoperative assessment of vitreoretinal diseases including diabetic retinopathy.

Background: The incidence of hepatocellular carcinoma (HCC) in southern China, including Guangxi Province, is among the highest in the world. Investigations of the etiology of HCC in this area have focused on hepatitis B virus (HBV) and aflatoxin. However, hepatitis C virus (HCV) has been shown to be a possible pathogenic agent for HCC in a number of countries., Methods: Antibodies to HCV (anti-HCV), determined by second-generation enzyme immunoassay, and hepatitis B surface antigen (HBsAg) were assayed in the sera of 186 patients with HCC and 48 healthy control subjects from Guangxi Province in southern China., Results: HBsAg was detected in 131 (70.4%) of 186 patients with HCC, whereas only 10 (5.4%) patients were found to be positive for anti-HCV. The prevalence of anti-HCV in patients with HBsAg-positive HCC was 6.9% (9 of 131) and that in patients with HBsAg-negative HCC was 1.8% (1 of 55); there was no significant difference between these two groups. Anti-HCV was not detected in any of the healthy control subjects, in whom the prevalence of HBsAg was 10.4% (5 of 48)., Conclusions: These findings indicate that HCV does not seem to play an important role in the development of HCC in Guangxi Province; however, HBV infection appears to be a major pathogenic factor for HCC in this area.

The depressant effect of interferon beta on drug-metabolizing activity in the human liver was investigated. Seven patients with chronic hepatitis C were treated with interferon beta at doses of 3 x 10(6) to 9 x 10(6) IU/day for 8 wk. The activities of 7-methoxycoumarin O-demethylase and 7-ethoxycoumarin O-deethylase in specimens obtained by liver biopsy were examined before and after interferon treatment. Theophylline pharmacokinetics were also examined before and after interferon treatment. Interferon beta treatment reduced the activities of both O-dealkylases from 6.0 (100%) to 3.2 (53%) nmol/gm liver per minute and from 1.9 (100%) to 1.1 (58%) nmol/gm liver per minute, respectively (p < 0.05). The total body clearance of theophylline was also decreased (from 0.76 to 0.56 ml/kg/min; p < 0.05), and its elimination half-life was increased (from 8.4 to 11.7 hr; p < 0.05); however, the volume of distribution was not significantly affected. The magnitude of the decreases in enzyme activities and in theophylline clearance varied widely in individual patients and did not correlate with the dose of interferon administered. This study provides the first direct evidence that interferon beta can depress the activity of drug-metabolizing enzymes in the human liver.

Background: Hypothyroidism may result from the production of antibodies that block the actions of thyrotropin. How often these thyrotropin-blocking antibodies are a cause of hypothyroidism and whether their production may cease, causing hypothyroidism to disappear, have not been extensively studied., Methods: We determined the frequency with which thyrotropin-blocking antibodies were present in 172 hypothyroid patients with goitrous autoimmune thyroiditis (Hashimoto's disease) and 64 hypothyroid patients with atrophic autoimmune thyroiditis (idiopathic primary hypothyroidism). For 6 to 11 years we then followed 21 of these patients who were found to have thyrotropin-blocking antibodies. They received levothyroxine therapy for 3.5 to 8 years, after which it was discontinued. At frequent intervals during this time we measured the patients' serum concentrations of thyroxine, triiodothyronine, thyrotropin, and thyrotropin-blocking antibodies (measured as immunoglobulins that inhibit thyrotropin binding and immunoglobulins that inhibit thyrotropin bioactivity)., Results: Thyrotropin-blocking antibodies were detected in 9 percent of the patients with goitrous autoimmune thyroiditis and in 25 percent of those with atrophic autoimmune thyroiditis. Among the 21 patients studied serially while receiving levothyroxine, thyrotropin-blocking antibodies disappeared in 15 (group 1), 7 of whom had goiter initially, and persisted in 6 (group 2), none of whom had goiter initially. Levothyroxine therapy was subsequently discontinued in these 21 patients. Six of those in group 1 (four with goiter) remained euthyroid (mean follow-up after discontinuation of therapy, 2.1 years), and nine became hypothyroid again within 3 months. All six patients in group 2 remained hypothyroid., Conclusions: Hypothyroidism in some patients with autoimmune thyroiditis may be due to thyrotropin-blocking antibodies. The production of thyrotropin-blocking antibodies may subside, producing remissions of hypothyroidism. Chronic autoimmune thyroiditis may therefore cause transient as well as permanent hypothyroidism.

The depressant effect of interferon-alpha on drug metabolizing activity in the liver has been investigated in 12 patients with chronic active hepatitis B. 7-methoxy-coumarin (7-MC) O-demethylase and 7-ethoxycoumarin (7-EC) O-deethylase, in specimens obtained by liver biopsy, were measured before and after interferon treatment. 7-MC and 7-EC O-dealkylase activity were significantly reduced after interferon treatment, from 13.4 to 9.24 nmol.g-1 liver.min-1, and from 3.22 to 2.16 nmol.g-1 liver.min-1, respectively. The magnitude of the fall varied widely between individual patients. The study provides the first direct evidence that interferon-alpha can impair the activity of drug metabolizing enzymes in the human liver.

Insulin-like growth factor (IGF-I) stimulates thyroid cell proliferation. Using primary cultured porcine thyroid cells, we studied the intracellular pathways that mediate the action of IGF-I on thyroid cell proliferation. IGF-I stimulates inositol phosphate accumulation, a rise in cytoplasmic free calcium [( Ca2+]i), and cell proliferation. Exposure to IGF-I results in a time- and dose-dependent accumulation of inositol monophosphate, inositol bisphosphate, and inositol trisphosphate. IGF-I also increases [Ca2+]i, measured using fura-2, a fluorescent Ca2+ indicator; the IGF-I-induced [Ca2+]i response occurs immediately, reaches a maximum within 1 min, and then slowly declines. IGF-I stimulates thyroid cell proliferation, stimulates thymidine incorporation, and increases cell numbers. The IGF-I-induced inositol phosphate accumulation and [Ca2+]i response parallel thyroid cell proliferation in a dose-dependent manner; the maximal response is observed at a concentration of 100 ng/ml IGF-I, with half-maximal stimulation at approximately 10 ng/ml. Inositol phosphate accumulation and [Ca2+]i response after IGF-I stimulation may function as intracellular messengers for thyroid cell proliferation. This report may constitute the first demonstration of IGF-I-stimulated inositol phosphate accumulation and [Ca2+]i response in the cells.

The initial signal for thyroid cell proliferation is unknown. This is the first report to show that epidermal growth factor (EGF) produces inositol phosphates and increases cytoplasmic free calcium ([Ca2+]i) in the thyroid gland. In cultured porcine thyroid cells, 10 nM EGF produces a breakdown of phosphatidylinositol and stimulates inositol phosphate production. Ten nM EGF increases [Ca2+]i, measured using fura-2, a fluorescent Ca2+ indicator; the EGF-induced [Ca2+]i response occurs immediately, reaches a maximum within several seconds, and then slowly declines. EGF stimulates production of inositol phosphates, which seem to increase [Ca2+]i. Inositol phosphate production and an increase in [Ca2+]i after EGF-stimulation may function as an initial signal for thyroid cell proliferation.

Porcine thyroid cells were cultured on collagen gel-coated cover glasses. They were reorganized into polarized monolayer cells; the basal cell membranes were in contact with the collagen gel, and the apical ones faced the culture medium. We studied cytoskeleton organization, resting membrane potentials, and iodine uptake of these cells. The quick-freezing and deep-etching replica method provided three-dimensional images of the cytoskeleton organization. Networks of microfilaments were observed under the apical cell membrane. In the deep cytoplasm and near the basal cell membranes, intermediate filaments predominated and were interlinked with the microfilaments. When the cells were cultured in the presence of TSH, TSH induced the formation of microvilli at the apical cell membranes and the accumulation of microfilaments under these membranes; in the deep cytoplasm, the intermediate filaments were more closely interlinked with the microfilaments. The microfilaments were immunostained with antiactin antibody. Thus, collagen is a factor in determining the cell polarity, and TSH further augments polarization through reorganizing the cytoskeletons. Electrophysiological study revealed that the resting membrane potential of cells cultured in the absence of TSH was -46 mV, and that of cells cultured in the presence of TSH was -58 mV. TSH hyperpolarized resting membrane potentials. These cells took up iodine. TSH in the medium augmented this uptake. TSH augments thyroid cell polarization through reorganizing the cytoskeletons and hyperpolarizing the resting membrane potentials and enhances iodine uptake by the cells.

Bilateral congenitally short fourth metatarsal bones were osteotomized subperiosteally, held in neutral position for 3 weeks by a small external fixator, and then subjected to slow axial distraction (0.25 mm/12h). The overall treatment time was 11 weeks, and the final increase in length was 14 mm for the left and 12 mm for the right metatarsal bone.

The effects of six inducers and malotilate on 7-alkoxycoumarin O-dealkylase activities in rat liver microsomes were examined. Phenobarbital (PB) (100 mg/kg) was administered intraperitoneally to rats for 6 days; 3-methylcholanthrene (3-MC) (40 mg/kg), beta-naphthoflavone (beta-NF) (40 mg/kg), isosafrole (150 mg/kg) and polychlorinated biphenyls (PCB) (100 mg/kg) were administered intraperitoneally for 3 days; isoniazid (INH) (50 mg/kg) was administered intraperitoneally for 10 days; and malotilate (500 mg/kg) was administered orally for 3 days. The O-dealkylase activities toward 7-methoxycoumarin (7-MC), 7-ethoxycoumarin (7-EC) and 7-propoxycoumarin (7-PC) were examined 24 hr after the final administration of the drugs. The ratios of 7-EC O-deethylase and 7-PC O-depropylase to 7-MC O-demethylase activity in the control and six inducer-treated groups were compared. The ratios in the groups treated with the six compounds, each of which induces a different form(s) of cytochrome P-450 (P-450), were clearly different from each other. Therefore, the measurement of 7-alkoxycoumarin O-dealkylase activities should be extremely useful for the routine determination of the molecular species of P-450. On the other hand, the ratio in the malotilate-treated group was different from that in any other inducer-treated group, so that there might be a possibility that malotilate induced a form(s) of P-450 that is different from any of the already known species.

The physical dependence liability of guanabenz, a hypotensive agent with central noradrenergic alpha 2-agonistic activity, was investigated. 1) Guanabenz showed a potent analgesic effect nearly equipotent to morphine by the modified Haffner's method, and repeated p.o. treatment resulted in the development of tolerance to the effect. 2) In the combined treatment of guanabenz with morphine or hexobarbital, it potentiated morphine analgesia and prolonged hexobarbital hypnosis in a dose dependent manner. 3) The natural withdrawal signs appearing in morphine or barbital dependent mice was suppressed by guanabenz; however, the effect was accompanied by a marked loss of body weight and weakness of the animals, and especially the dose required for the suppression of barbital withdrawal signs was extremely high and was even lethal in some cases. A substitution test in barbital dependent mice showed that guanabenz could not substitute for barbital. In the primary dependence test after 30 days oral treatment with guanabenz, no appreciable withdrawal signs were observed after discontinuation of the administration. Thus, from the results obtained in the present experiments, it is revealed that guanabenz possesses no physical dependence liability of the morphine or barbital type.