Yuichi Kinoshita

Green Tea Extract-induced Acute Hepatotoxicity in Rats

Although green tea is considered to be a healthy beverage, hepatotoxicity associated with the consumption of green tea extract has been reported. In the present study, we characterized the hepatotoxicity of green tea extract in rats and explored the responsible mechanism. Six-week-old IGS rats received a single intraperitoneal (ip) injection of 200 mg/kg green tea extract (THEA-FLAN 90S). At 8, 24, 48 and 72 hrs and 1 and 3 months after exposure, liver damage was assessed by using blood-chemistry, histopathology, and immunohistochemistry to detect cell death (TUNEL and caspase-3) and proliferative activity (PCNA). Analyses of malondialdehyde (MDA) in serum and the liver and of MDA and thymidine glycol (TG) by immunohistochemistry, as oxidative stress markers, were performed. Placental glutathione S-transferase (GST-P), which is a marker of hepatocarcinogenesis, was also immunohistochemically stained. To examine toxicity at older ages, 200 mg/kg green tea extract was administered to 18-wk-old female rats. In 6-wk-old rats, 12% of males and 50% of females died within 72 hrs. In 18-wk-old rats, 88% died within 72 hrs. The serum levels of aspartate aminotransferase, alanine aminotransferase and/or total bilirubin increased in both males and females. Single-cell necrosis with positive signs of TUNEL and caspase-3 was seen in perilobular hepatocytes from 8 hrs onward in all lobular areas. PCNA-positive hepatocytes increased at 48 hrs. MDA levels in the serum and liver tended to increase, and MDA- and TG-positive hepatocytes were seen immunohistochemically. GST-P–positive hepatocellular altered foci were detected in one female rat at the 3-month time point. In conclusion, a single injection of green tea extract induced acute and severe hepatotoxicity, which might be associated with lipid peroxidation and DNA oxidative stress in hepatocytes.

Retrospective cytological study of intraocular lymphoma using vitreous and intraocular perfusion fluid

Intraocular lymphoma (IOL) is an extremely rare tumor. We carried out a retrospective cytopathological study with vitreous and intraocular perfusion fluid obtained on conducting a pars plana vitrectomy in 18 cases of IOL. In the 18 cases, nine were patients of Kansai Medical University Takii Hospital from 1991 to 2007, and the other nine had already been reported by other hospitals. Most patients were male, and the average age at onset was 60.4‐year‐old. The main symptoms were vitreous opacity, amblyopia, and blurred vision. Cases of primary intraocular lymphoma numbered 8/15 (53%), while cases of infiltration of malignant lymphoma from the brain numbered 2/15 (13%). Although IOL contains various subtypes of lymphoma, the most frequent subtype is diffuse large B‐cell type lymphoma.

N -ethyl- N -nitrosourea induces retinal photoreceptor damage in adult rats.

Seven-week-old male Lewis rats received a single intraperitoneal injection of N-ethyl-N-nitrosourea (ENU) (100, 200, 400 or 600 mg/kg), and retinal damage was evaluated 7 days after the treatment. Sequential morphological features of the retina and retinal DNA damage, as determined by a TUNEL assay and phospho-histone H2A.X (γ-H2AX), were analyzed 3, 6, 12, 24 and 72 hr, 7 days, and/or 30 days after 400 mg/kg ENU treatment. Activation of the nuclear enzyme poly (ADP-ribose) polymerase (PARP) was analyzed immunohistochemically by poly (ADP-ribose) (PAR) expression in response to DNA damage of the retina. All rats that received ≥ 400 mg/kg of ENU developed retinal degeneration characterized by the loss of photoreceptor cells in both the central and peripheral retina within 7 days. In the 400 mg/kg ENU-treated rats, TUNEL-positive signals were only located in the photoreceptor cells and peaked 24 hr after ENU treatment. The γ-H2AX signals in inner retinal cells appeared at 24 hr and peaked at 72 hr after ENU treatment, and the PAR signals selectively located in the photoreceptor cell nuclei appeared at 12 hr and peaked at 24 hr after ENU treatment. However, degeneration was restricted to photoreceptor cells, and no degenerative changes in inner retinal cells were seen at any time points. Retinal thickness and the photoreceptor cell ratio in the central and peripheral retina were significantly decreased, and the retinal damage ratio was significantly increased 7 days after ENU treatment. In conclusion, ENU induced retinal degeneration in adult rats that was characterized by photoreceptor cell apoptosis through PARP activity.

Diagnostic utility of vitreous humor fluid cytology for intraocular sarcoidosis: A clinicopathologic study of 7 cases

Sarcoidosis is an enigmatic multisystem sarcoid disease occurring mainly in the lungs, skin, and eyes. Sarcoidosis of the eyes (intraocular sarcoidosis) has been proposed as one of the causes of uveitis. We carried out a clinicopathological study involving seven patients with intraocular sarcoidosis based on vitreous humor fluid cytology.

Histopathological and immunohistochemical characterization of spontaneously occurring uterine deciduomas in young adult rats.

Uterine deciduomas were found in two female virgin rats, a 15-week-old Lewis rat and a 7-week-old Sprague-Dawley rat. The firm white nodules were located at the base of unilateral uterine horns and were approximately 6 mm and 4 mm in diameter. Histopathologically, the nodules were composed of three areas, each with a distinct type of proliferating cells: large epithelioid decidual cells with round nuclei, prominent nucleoli and abundant eosinophilic cytoplasm (antimesometrial region); compact spindle-shaped cells with oval nuclei and vacuolar cytoplasm (transitional region); and pleomorphic and spiny cells with round to oval nuclei and compact eosinophilic cytoplasm (mesometrial region). These cells proliferated in sheet-like arrangements and transformed into the other types of cells located in surrounding regions. Immunohistochemically, proliferating cells in all regions were strongly positive for proliferating cell nuclear antigen. The proliferating cells were positive for vimentin, and large decidual cells were positive for common acute lymphoblastic leukemia antigen 10, a marker of uterine interstitial cells. Large decidual cells were positive for α-smooth muscle actin and desmin, suggesting differentiation into muscular cells. Progesterone receptor was expressed in all cell types; however, estrogen receptor α was not expressed in the antimesometrial region. These extremely rare tumor-like nodules represent nonneoplastic lesions referred as decidual reactions of endometrial interstitial cells, and their biological behavior is that of a space-occupying benign tumor in young rats. Our cases might provide information as a historical control in toxicity and pharmacological studies in rats.

Two cases of malignant peritoneal mesothelioma without asbestos exposure: cytologic and immunohistochemical features

Approximately half a century has passed since asbestos was first reported to be the main cause of malignant mesothelioma; yet the incidence of this disease continues to increase worldwide. Twenty percent of cases occur without prior asbestos exposure, and in these patients, malignant peritoneal mesothelioma is more common than malignant pleural mesothelioma. Here, we report the cytomorphologic and immunohistochemical features of 2 cases of malignant peritoneal mesothelioma where there was no history of asbestos exposure. Ascitic cytology showed that most cells were isolated and that clusters were rarely observed, but the findings were consistent with malignant mesothelioma in both cases. Immunohistochemical analysis for epithelial membrane antigen, calretinin, vimentin, β-catenin, melan-A, glucose transporter-1, cytokeratin CAM5.2, Wilms tumor antigen-1, D2-40, CD146, progesterone receptor, estrogen receptor, and cytokeratin 5/6 was indicative of malignant mesothelioma. In malignant mesothelioma without prior asbestos exposure, the etiology and prognostic significance is still unclear. Further study is needed to clarify this point.

Leiomyomatosis Peritonealis Disseminata Positive for Progesterone Receptor

Patient: Female, 30 Final Diagnosis: Leiomyomatosis Symptoms: Abnormal finding in abdominal-pelvic CT scan Medication: — Clinical Procedure: Surgical tumorectomy Specialty: Oncology Objective: Rare disease Background: Leiomyomatosis peritonealis disseminata (LPD) is a rare condition that occurs in reproductive-age women. The pathogenesis of LPD is considered to be related to female sex hormones. Case Report: A 30-year-old woman who had undergone an ovariectomy due to calcified thecoma at 24 years of age and had delivered a baby boy at 29 years of age showed abnormal abdominal-pelvic masses in a computed tomography scan. The peritoneal nodules were resected and histologically diagnosed as LPD. Smooth muscle cells in LPD lesions expressed progesterone receptor, while estrogen receptor and luteinizing hormone/chorionic gonadotropin receptor were negative. Conclusions: LPD should be considered when multiple nodules mimicking dissemination of malignancies are found in the abdominal cavity. In the present case, progesterone may have been involved in the pathogenesis of LPD.

Trousseau's Syndrome Caused by Intrahepatic Cholangiocarcinoma: An Autopsy Case Report and Literature Review

An autopsy case report of Trousseaus syndrome caused by intrahepatic cholangiocarcinoma is presented, and seven previously reported cases are reviewed. A 73-year-old woman experiencing light-headedness and dementia of unknown cause for 6 months developed severe hypotonia. A hypointense lesion compatible with acute cerebral infarction was detected by magnetic resonance imaging. Abdominal computed tomography revealed an ill-defined large liver mass in the right lobe. The mass was not further investigated because of the patients poor condition. She died of multiple organ failure, and an autopsy was conducted. Postmortem examination revealed intrahepatic cholangiocarcinoma, fibrous vegetations on the mitral valves and multiple thromboemboli in the cerebrum, spleen and rectum. Trousseaus syndrome is defined as an idiopathic thromboembolism in patients with undiagnosed or concomitantly diagnosed malignancy. This syndrome is encountered frequently in patients with mucin-producing carcinomas, while the incidence in patients with intrahepatic cholangiocarcinoma is uncommon. We found that tissue factor and mucin tumor marker (CA19-9, CA15-3 and CA-125) expression in cancer cells may be involved in the pathogenesis of thromboembolism. A patient with unexplained thromboembolism may have occult visceral malignancy; thus, mucin tumor markers may indicate the origin of a mucin-producing carcinoma, and postmortem examination may play an important role in revealing the hidden malignancy.

Arachidonic acid supplementation does not affect N-methyl-N-nitrosourea-induced renal preneoplastic lesions in young Lewis rats

Arachidonic acid (AA) is naturally found in human breast milk. AA, together with docosahexaenoic acid, is commonly added as a functional food ingredient to commercial infant formula worldwide, in accordance with the international standards of Codex Alimentarius. However, few studies of the possible renal carcinogenic effects of AA supplementation during neonatal life have been performed. The effect of dietary AA supplementation in dams during gestation and lactation was investigated on N-methyl-N-nitrosourea (MNU)-induced preneoplastic lesions in the kidneys of young Lewis rats. Dams were fed a 2.0% AA diet or a basal diet (<0.01% AA). At birth (postnatal day 0), male and female pups received a single intraperitoneal injection of 35 mg/kg MNU or vehicle. Renal morphology was examined after 7, 14, 21, 28 and 60 days. Histopathologically, renal preneoplastic lesions, such as nephroblastomatosis and mesenchymal cell proliferation, were found on day 60 in both the MNU-treated groups. There was no significant difference in lesion incidence of 38% in the basal diet group and 31% in the AA diet group. In conclusion, an AA-rich diet for dams during gestation and lactation does not modify MNU-induced renal preneoplastic lesions in their offspring.

Susceptibility to N-methyl-N-nitrosourea-induced retinal degeneration in different rat strains

To evaluate the potential role of genetic background in the susceptibility to retinal degeneration induced by N-methyl-N-nitrosourea (MNU), female rats of the Sprague-Dawley (SD), Long-Evans (LE) and Copenhagen (CH) strains were administered 50 mg/kg MNU or saline at 7 weeks of age. Retina morphology and morphometric analysis of all rats was performed 7 days after MNU administration. Atrophy of both the peripheral and central outer retina occurred in all rat strains exposed to MNU. Decreased photoreceptor cell ratio and increased retinal damage ratio were observed. The severities of the retinal atrophy were similar among all three rat strains. In conclusion, MNU-induced photoreceptor degeneration developed consistently in all three strains regardless of the absence (SD rats) or presence (LE and CH rats) of melanin in the retina, suggesting that genetic and melanin factors did not affect photoreceptor cell death after MNU.