Research communications in molecular pathology and pharmacology最新文献

Hepatic drug metabolism (flavin-containing monooxygenase (FMO), glutathione related enzymes, phase II conjugation reactions) and the hepatic contents of glutathione were investigated in normal rats, alloxan induced diabetic rats and streptozotocin (STZ) induced diabetic rats. The hepatic content of reduced or oxidized glutathione, the activities of glutathione related enzymes (glutathione reductase and glutathione peroxidase) and several enzymes (p-nitrophenol glucuronosyltransferase, aryl sulphotransferase I and II) involved in conjugation reactions were lower in alloxan- and STZ-induced diabetic rats than those in normal rats. In contrast, the activities of FMO and aryl sulphotransferase IV were significantly higher in alloxan- and STZ-induced diabetic rats than those in normal rats. Glutathione S-transferase (GST) activity also was remarkably higher in STZ-induced diabetic rats than that in normal rats. Insulin administered to STZ-induced diabetic rats prevented the hyperglycemia indicative of STZ-induced diabetes, but had no effect on the increased activities of GST. Another diabetogenic agent, alloxan, did not alter the activities of GST. On the other hand, the fluctuations in the enzymatic activities of FMO, UDP-glucuronosyltransferase, aryl sulphotransferase and glutathione related enzymes were restored to normal level by treatment with insulin in both diabetic rats. These results show that STZ may be directly increasing activities of GST, and not as a result of the diabetic state the diabetogenic agent induces. However, the fluctuations of the activities of FMO, glutathione related enzymes and some phase II reactions were dependent on diabetic states.

Physical exercises have been recommended in the prevention of non-insulin dependent diabetes mellitus (NIDDM), but the mechanisms involved in this intervention are not yet fully understood. Experimental models offer the opportunity for the study of this matter. The present study was designed to analyze the diabetes evolution in rats submitted to neonatal treatment with alloxan with the objective of verifying the suitability of the model to future studies with exercises. For this, newly born rats (6 days old) received intraperitoneal alloxan (A=200 mg/kg of body weight). Rats injected with vehicle (citrate buffer) were used as controls (C). The fasting blood glucose level (mg/dL) was higher in the alloxan group at the day 28 (C=47.25 +/- 5.08; A=54.51 +/- 7.03) but not at the 60 day of age (C=69.18 +/- 8.31; A=66.81 +/- 6.08). The alloxan group presented higher blood glucose level during glucose tolerance test (GTT) (mg/dL. 120 min) in relation to the control group both at day 28 (C=16908.9 +/- 1078.8; A=21737.7 +/- 1106.4) and at day 60 (C=11463.45 +/- 655.30; A=15282.21 +/- 1221.84). Insulinaemia during GTT (ng/mL. 120 min) was lower at day 28 (C=158.67 +/- 33.34; A=123.90 +/- 19.80), but presented no difference at day 60 (C=118.83 +/- 26.02; A=97.88 +/- 10.88). At day 60, the glycogen concentration in the soleus muscle (mg/100 mg) was lower in the alloxan group (0.3 +/- 0.13) in relation to the control group (0.5 +/- 0.07). No difference was observed between groups in relation to (micromol/g.h): Glucose Uptake (C=5.8 +/- 0.63; A=5.2 +/- 0.73); Glucose Oxidation (C=4.3 +/- 1.13; A=3.9 +/- 0.44); Glycogen Synthesis (C=0.8 +/- 0.18; A=0.7 +/- 0.18) and Lactate Production (C=3.8 +/- 0.8; A=3.8 +/- 0.7) by the isolated soleus muscle. The glucose-stimulated insulin secretion (16.7mM) by the isolated islets (ng/5 islets. h) of the alloxan group was lower (14.3 +/- 4.7) than the control group (32.0 +/- 7.9). Thus, we may conclude that this neonatal diabetes induction model gathers interesting characteristics and may be useful for further studies on the role of the exercise in the diabetes mellitus appearance.

Pharmacokinetic parameters of DA-8159 and one of its metabolites, DA-8164, were compared after intravenous and oral administration of DA-8159 at a dose of 30 mg/kg to control rats and rats pretreated with Klebsiella pneumoniae lipopolysaccharide (KPLPS). After intravenous and oral administration of DA-8159, most of the pharmacokinetic parameters of DA-8159 and DA-8164 were not significantly different between two groups of rats. This suggested that the pharmacokinetic parameters of DA-8159 and DA-8164 were not affected considerably by KPLPS.

Diabetes and its metabolic changes in peripheral nerves contribute to cause a decrease of nitric oxide production and diminished nerve blood flow. Since lipid peroxides are thought to be formed by free radicals and may play an important role in the development of vascular disease, we have investigated the possible relationship between lipid peroxides (measured as thiobarbitouric acid reacting substances (TBARS) in diabetic patients with peripheral neuropathy. Seventy-seven patients with Type 2 diabetes (39 neuropathic and 38 non-neuropathic) and 38 control subjects were studied. The neuropathy study group had significantly lower levels of TBARS, 3.5micromol/l (2.2-5.6, 95% confidence limits) compared to controls 4.5microm/l (3.08-6.8), p < 0.001 and to diabetics without neuropathy 4.9micromol/l (3.09-8.05), p < 0.001. No differences were found in metabolic control between the two diabetic groups. In the neuropathy group there was a negative correlation between the score for nerve dysfunction with the TBARS levels (r = - 0.42, p < 0.01). In conclusion, in diabetic patients with neuropathy there are abnormalities of TBARS levels.

Hyperthermia-induced cellular response has been widely investigated for understanding cell physiology in stressful conditions as well as for therapeutic application using heat shock. In this study, the protective effect of mild hyperthermia-induced cellular response was investigated in RKO human colon cell lines, which harbor wild-type p53. Our data showed that the accumulation of p53 protein was induced without DNA damage in response to mild hyperthermia. Interestingly, the sub-lethal of heat shock at 40 degrees C for 30 minutes in RKO cells showed the protective effect against UV mimetic agent 4-nitroquinoline-1-oxide (4NQO) with the decrease in mitotic index, although other papers had shown the induction of apoptosis in RKO cells under the higher dose of heat stress. Thus, we suggest that the protective effect of sub-lethal heat shock might be applicable for a novel preventive approach to clinical applications of mild hyperthermia.

Poly(ADP-ribose) polymerase-1 (PARP-1) is a nuclear enzyme involved in the detection of DNA strand termini. Extensive cellular damage can overactivate PARP-1, which rapidly depletes the cellular stores of NAD+ and ATP, resulting in necrotic cell death. The purpose of the present study was to determine whether 6(5H)-phenanthridinone, a potent inhibitor of PARP-1, could attenuate the hepatotoxicity of carbon tetrachloride (CCl4). Male ICR mice treated via the intraperitoneal route with CCl4 exhibited severe necrotic centrilobular lesions and significantly elevated serum transaminases. In contrast, the histopathology and serum biochemistry of animals treated concomitantly with CCl4 and 6(5H)-phenanthridinone were not significantly different versus controls. In conclusion, the results of this study demonstrate that the hepatotoxicity of CCl4 can be blocked independently of its metabolism and suggest the predominant role of PARP-1 overactivation in chemical-induced toxicity.

The procalcitonin (PCT) level in the blood was determined in cases of acute pancreatitis. The PCT level was found to show a significant correlation with the severity of acute pancreatitis. Furthermore, the PCT level was significantly higher in the cases which developed MODS than in those which did not. The PCT level was significantly higher in the patients who eventually died than in those who survived. A significant correlation was observed between the serum PCT level and the serum tumor necrosis factor alpha level. Thus, PCT level was found to be a reliable indicator of the severity of acute pancreatitis.

This investigation was performed to evaluate the effects of nimesulide (NIM), a selective cyclo-oxygenase-2 (COX-2) inhibitor, on forebrain ischemia-induced in vivo oxidative stress damage in the rat hippocampus. Hippocampal tissue glutathione (GSH) and malondialdehyde (MDA) contents, the activities of the antioxidants superoxide dismutase (SOD) and catalase as well as nitric oxide (NO) concentration were estimated. A clinically relevant dose of NIM (18 mg x kg(-1) x d(-1), p.o.) was administered immediately after induction of forebrain ischemia for 7 consecutive days. Forebrain ischemia induced oxidative stress after 7 days manifested by significant decrease in GSH and increase in MDA levels as compared to control (p < 0.05). Also, in rats subjected to ischemia, SOD and catalase activities were decreased significantly compared to the control group (p < 0 .05). On the other hand, ischemic rats showed a significant increase in NO concentration compared to those in the control group (p < 0.05). Treatment with NIM protected the rats from ischemia-induced oxidative stress as evident by normalization of measured parameters. The present study indicates the ability of NIM to reduce oxidative stress induced by transient forebrain ischemia. This suggests that the induction of COX-2 might be involved in transient forebrain ischemia-induced oxidative damage and hence the selective COX-2 inhibitors might be a valuable therapeutic strategy against ischemic brain injury.

Matrix metalloproteinases (MMPs) have been implicated in the tumor invasion and growth through the degradation of extracellular matrix. In this study, we selected 46 hepatocellular carcinoma (HCC) cases, at random, and we immunohistologically examined the expression of MMP-1, MMP-2, MMP-3, MMP-7, MMP-9, tissue inhibitor of metalloproteinases (TIMP)-1, TIMP-2, in cancerous and non-cancerous areas using avidin-biotin-peroxidase complex method. In all cases, cancer cells, hepatocytes, sinusoidal lining cells, leukocytes, and bile ducts were positive for all the primary antibodies. The expressions of MMPs and TIMPs in most of the HCC tissues were equal or low compared with those in the surrounding non-tumor tissues, although mixed expression pattern were recognized in some HCC tissues. The difference of MMP and TIMP expression was not related with the histological differentiation of HCC and the condition of non-cancerous area. These findings suggested little association of the clinicopathological findings of HCC with the histological expression of MMPs and TIMPs.

N-acetylation plays an important role in the metabolism of arylamine drugs and carcinogens and is catalyzed by cytosolic N-acetyltransferase (NAT). Gypenosides are the major components of Gynostemma pentaphyllum Makino which had been used as a natural folk medicine in the Chinese populations. Gypenosides were selected for examining the inhibition on the N-acetylation of 2-aminofluorene (AF), DNA-AF adduct formation and NAT gene expression in the human cervix epithelioid carcinoma cell line (HeLa). Various concentrations of gypenosides were individually added to the culture medium of human cervix epithelioid carcinoma cells (HeLa). The N-acetylation of AF was determined by high performance liquid chromatography (HPLC) assaying for the amounts of acetylated 2-aminofluorene (AAF) and nonacetylated 2-aminofluorene (AF). The N-acetylation of AF in the human HeLa cancer cells was suppressed by gypenosides in a dose-dependent manner. The data also demonstrated that gene expression (NAT1 mRNA) of NAT in human cervix epithelioid carcinoma cells (HeLa) was inhibited and decreased by gypenosides. After the incubation of HeLa cells with 30 or 60 microM AF and with or without 350 microg/ml gypenosides cotreatment, DNA was isolated and hydrolyzed to nucleotides, adducted nucleotides were extracted into butanol and analyzed DNA-AF adducts by HPLC. The data demonstrated that gypenosides decrease the levels of DNA-AF adduct formation in HeLa cells.