Mechanistic study on liver tumor promoting effects of flutamide in rats.

Flutamide (FLU), a nonsteroidal anti-androgen, is used for the treatment of prostate cancer but is also a cytochrome P450 (CYP) 1A inducer. Some CYP1A inducers are known to exert hepatocellular tumor-promoting activities in rodents, and reactive oxygen species (ROS) produced by CYP1A1 induction via a metabolism of FLU is probably involved in the liver tumor promotion. In the present study, to clarify the possible liver tumor promoting effect of FLU, a two-stage liver carcinogenesis assay was performed using male F344 rats. Rats received an intraperitoneal (ip) injection of 200 mg/kg body weight of N-diethylnitrosamine (DEN) and fed a diet containing 0, 0.1 or 0.2% FLU for 6 weeks. After 2 weeks of DEN treatment, all rats were subjected to two-thirds partial hepatectomy. Animals were killed 8 weeks after ip injection of DEN. Immunohistochemically, the number and area of glutathione S-transferase placental form (GST-P)-positive foci significantly increased in the liver of rats given 0.2% FLU as compared with the control. Ki-67-positive cell ratio also increased in rats given FLU at both concentrations. ROS generation in the microsomal fraction and production of thiobarbituric acid-reactive substance [TBARS] and 8-hydroxy-2'-deoxyguanosine (8-OHdG) content in the liver did not increase in any of the FLU-treated groups. The results of microarray and real-time RT-PCR revealed that phase 1 drug-metabolizing enzymes such as CYP1A1, Ugt1a61 and Nqo1 and phase II drug-metabolizing enzymes such as Yc2, Akr1b7, Akr1b8, Akr1b10, Aldh1a1, Gpx2 and Me1 were up-regulated in rats treated with FLU. In addition, the MAPK pathway family-related genes such as Prkcα, Mek1, Rafb, Myc, Mek2, Raf1 and Egfr were also up-regulated in FLU-treated groups. The results of the present study indicate that FLU is a CYP1A inducer but does not cause any production of microsomal ROS in the liver and suggest that microsomal ROS is not involved in the liver tumor promoting effect of FLU.

Effects of opium inhalation on physical and biochemical parameters of stray dogs in Kabul city, Afghanistan.

Background: Afghanistan is one of the biggest opium-producing countries in the world. There are more than a million drug addicts in the country, and most of them are living in public places. Stray dogs who live with drug addicts are at the highest risk of inhaling drugs. Aim: The aim of this study is to evaluate changes in physical and biochemical parameters of stray dogs inhaling drugs. Methods: A total of 12 dogs were assigned into two groups healthy and infected (stray dogs who inhale drugs) dogs. The physical and biochemical parameters of both groups were evaluated. Results: Subjective evaluation showed clinical changes such as congestion of conjunctiva in the infected group. Biochemical examination showed a significantly higher level of glucose (p < 0.05) and total protein (TP) (p < 0.01) in the infected group compared to the healthy group. The ratio of other biochemical parameters was slightly decreased as compared to healthy dogs. Conclusion: Drug inhalation can alter biochemical parameters like glucose and TP in dogs.

Evaluation of in vivo genotoxic potential of fenofibrate in rats subjected to two-week repeated oral administration.

Fenofibrate (FF), a peroxisome proliferator-activated receptor-alpha agonist, has been used as one of the hypolipidemic drugs in man and induces oxidative stress and promotes hepatocarcinogenesis in the liver of rodents. This chemical belongs to a class of non-genotoxic carcinogens, but DNA damage secondary to oxidative stress resulting from reactive oxygen species (ROS) generation is suspected in rodents given this chemical. To examine whether FF has genotoxic potential, partially hepatectomized F344 male rats were treated orally with 0, 1,000 or 2,000 mg/kg of FF for 2 weeks, followed by diet containing 0.15% 2 acetyl aminofluorene (2 AAF) for enhancement the tumor-promoting effect for 10 days and a single oral dose of carbon tetrachloride (CCl4) as the first experiment (liver initiation assay). As the second experiment, the in vivo liver comet assay was performed in hepatectomized rats, and the expression of some DNA repair genes was examined. In the liver initiation assay, the number and area of glutathione S-transferase placental form (GST-P)-positive single cells and foci did not increase in the FF treated groups. In the comet assay, positive results were obtained after 3 h of the last treatment of FF, and the expression of some DNA repair genes such as Apex1, Ogg1 and Mlh1 were upregulated in rats given the high dose of FF at 3 h after the treatment but not in 24 h after the treatment. The results of the present study suggest that FF causes some DNA damage in livers of rats, but is not a strong genotoxic substance leading to a DNA mutation since such DNA damage was repaired by the increased activity of some DNA repair genes.

Utility of serum thymidine kinase activity measurements for cases of bovine leukosis with difficult clinical diagnoses.

This study evaluated the clinical usefulness of serum thymidine kinase (TK) activity for diagnosing bovine leukosis cases for which clinical diagnosis was difficult ('BL with difficult diagnosis'). Median TK activity values in 24 'BL with difficult diagnosis' and 36 cattle for which BL was clinically confirmed by cytology findings of enlarged superficial lymph nodes ('clinically confirmed BL') were 36.8 and 39.4 U/l, respectively (no significant difference). The percentage with positive TK activity (> 5.4 U/l) was also similar in both groups (83.3% for 'BL with difficult diagnosis' and 97.2% for 'clinically confirmed BL'). TK activity was significantly higher in cows with 'BL with difficult diagnosis' compared to those with other tumors (N = 13) and those with inflammatory diseases (N = 14). Maximum TK activity in cows with other tumors and inflammatory diseases was not high (< 10 U/l). Median TK activities in cows with other tumors and those with inflammatory diseases were 1.8 and 1.4 IU/l, respectively. Positive TK activity was found in a significantly higher percentage of cows with 'BL with difficult diagnosis' (83.3%) relative to the percentages of cows with other tumors (15.3%) and inflammatory diseases (21.4%). Thus, TK activity is an appropriate marker for detecting BL onset in cows with 'BL with difficult diagnosis' as well as 'clinically confirmed BL' group. While the specificity of TK activity required for BL diagnosis is not clear, simultaneous evaluation of serum lactate dehydrogenase activity may assist in the differential diagnoses of other tumors and inflammatory diseases from BL.

Evaluation of gene expression in peripheral blood cells as a potential biomarker for enzootic bovine leukosis.

Expression of six selective genes in peripheral blood cells was evaluated as diagnostic biomarkers for enzootic bovine leukosis (EBL) by using 10 EBL and 15 clinically healthy cattle. The clinically healthy cattle generally showed lower gene expression levels. Although wide variations of gene expression were found in some clinical cases of EBL, 4 and 5 among 10 EBL cattle showed higher expression of interleukin 2 receptor gene (IL2R) and Wilms' tumor gene (WT1), respectively. Expression of IL2R in peripheral blood cells in EBL cattle was statistically increased; however, the lower sensitivity and higher variation in the gene expressions among clinical cases of EBL would be problems as diagnostic biomarkers.

Thymic lymphosarcoma with brain involvement in a Holstein heifer.

An 8-month-old Holstein heifer with cervical enlargement was suspected of thymic lymphosarcoma given clinical signs of depression, tendency to lie down, cervical mass, jugular vein distension, conjunctival hyperemia, and ruminal tympany. Unilateral Horner's syndrome was also observed. Increased serum total lactate dehydrogenase (LDH), LDH isozyme (LDH-2, and LDH-3) and serum thymidine kinase activity were observed. The findings of fine needle aspiration cytology of the cervical mass revealed large lymphoblasts with mitoses present. These findings strongly suggested the diagnosis of lymphosarcoma. Necropsy revealed a large mass in the cervical thymic region, which compressed the esophagus and trachea. Cranial masses in the frontal sinus and multiple extradural sites throughout the cranial vault were also recorded. Histopathological examination confirmed the diagnosis of thymic lymphosarcoma and demonstrated the brain involvement of neoplastic lymphoid cells in the cerebrum. This is a rare clinical case of thymic lymphosarcoma accompanied by brain metastasis in a Holstein heifer.

Overexpression of interleukin 2 receptor, thymidine kinase and immunoglobulin-associated alpha-1 messenger RNA in a clinical case of enzootic bovine leukosis.

A 49-month-old Holstein cow with anorexia, tachypnea, enlarged peripheral lymph nodes, and difficulty standing up was suspected of bovine leukosis. Hematological examination revealed lymphocytosis with the presence of neoplastic cells. Increased total lactate dehydrogenase (LDH) activity, isozymes of LDH-2 and LDH-3 activities and thymidine kinase activity were observed. Cytological findings of fine needle aspiration of subiliac lymph nodes indicated lymphosarcoma. Histopathology and antibody analysis confirmed the diagnosis of enzootic bovine leukosis, a B-cell bovine lymphoma caused by bovine leukemia virus. Gene expressions known as biomarkers of hematopoietic neoplasia in human were also examined in the present case. Increased messenger RNA expression of interleukin 2 receptor, thymidine kinase, and immunoglobulin-associated alpha-1 was observed in the case animal.

Calf form bovine leukosis with lameness in a Holstein heifer.

A 12-month-old Holstein heifer with anorexia, lameness, and enlargement of peripheral lymph nodes was suspected of having bovine leukosis. Although lymphocytosis was not observed, cytology of fine needle aspirate from a superficial cervical node, and increased serum lactate dehydrogenase and thymidine kinase activities, strongly suggested lymphosarcoma. Increased numbers of mononuclear cells as well as mitotic cells were observed in synovial fluid collected from swollen joints. Pathological examination confirmed B-cell calf form bovine leukosis and joint swelling related to neoplastic cell infiltration. Both interleukin-2 receptor and thymidine kinase 1 genes were highly expressed in cells from superficial cervical lymph node aspirate.