Yuko Emoto

Autopsy report for a caffeine intoxication case and review of the current literature

Caffeine (1,3,7-trimethylxanthine) is a popular mild central nervous system stimulant found in the leaves, seeds and fruits of various plants and in foodstuffs such as coffee, tea, and chocolate, among others. Caffeine is widely used and is not associated with severe side effects when consumed at relatively low doses. Although rarely observed, overdoses can occur. However, only a few fatal caffeine intoxication cases have been reported in the literature. Herein, we report the pathological examination results and information on caffeine concentrations in the blood, urine and main organs in a fatal caffeine intoxication case. Even though high caffeine concentrations were found in the systemic organs, no caffeine-related pathological changes were detected.

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.

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.

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.

N‑methyl‑N‑nitrosourea‑induced cerebellar hypoplasia in rats: Effect of arachidonic acid supplementation during the gestational, lactational and post‑weaning periods

Arachidonic acid (AA) is a fatty acid that is important for visual and brain development and is commonly added as a functional food ingredient to commercial infant formulas worldwide. However, few studies have examined whether AA supplementation during neonatal life has an effect on neuronal abnormalities. In the present study, the effect of dietary AA supplementation in dams during gestation and lactation was investigated by examining N-methyl-N-nitrosourea (MNU)-induced cerebellar hypoplasia in 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. Brain weights were measured and a morphological analysis of macroscopic and histological specimens was conducted after 7, 14, 21, 28 and 60 days. Irrespective of whether the rats had been fed an AA diet, the brain weights of the MNU-treated rats, particularly the weights of the cerebellum, were decreased compared with those of the MNU-untreated rats from the 14th day following the MNU injection. Macroscopic reductions in the cerebellar length and/or width and histologically observed reductions in cerebellar vertex height and/or cortex width were also detected in the MNU-treated rats, irrespective of whether the rats had been fed with AA. Histopathologically, the MNU-treated rats (irrespective of AA supplementation) exhibited disorganization of the cerebellar cortex and disarrangement of the cortical layers (loss and/or disturbance of the molecular, Purkinje and granular cell layers). There were no significant differences in any parameters among the MNU-treated rats, irrespective of whether the rats had been fed an AA diet. In conclusion, an AA-rich diet for dams during gestation and lactation did not modify MNU-induced cerebellar hypoplasia in their offspring.

Green tea extract attenuates MNU-induced photoreceptor cell apoptosis via suppression of heme oxygenase-1

The effects of green tea extract (GTE) on N-methyl-N-nitrosourea (MNU)-induced photoreceptor cell apoptosis were examined, and the possible mechanisms of action of GTE were assessed. Alterations in the retinal morphological architecture were determined by hematoxylin-eosin staining, vimentin immunoreactivity, and photoreceptor cell apoptosis (TUNEL labeling). Expression of oxidant marker, heme oxygenase (HO)-1, mRNA levels in outer nuclear cells was assessed by laser capture microdissection (LCM). Sprague-Dawley rats were given 40 mg/kg MNU at 7 weeks of age in the absence and presence of 250 mg/kg GTE treatment (once daily from 3 days prior to MNU for a maximum 10 days). Although photoreceptor cell degeneration began 24 hr after MNU, the morphological effects of GTE at the time point were not definitive. However, GTE lowered TUNEL labeling and HO-1 mRNA expression. At 7 days after MNU, photoreceptor damage was attenuated by GTE treatment. Therefore, the ability of GTE to reduce MNU-induced photoreceptor cell apoptosis may be due to its antioxidant properties.

A spontaneously occurring malignant ovarian Sertoli cell tumor in a young Sprague Dawley rat

Primary ovarian tumors are generally uncommon in rats used in toxicologic studies. A malignant Sertoli cell tumor was present in the ovary of a 19-week-old female Sprague Dawley rat. Macroscopically, the mass was white and firm, 10 × 13 × 17 mm in size, and located in the right ovary. Histopathologically, the mass was composed of nests of pleomorphic cells, which formed seminiferous-like tubules separated by a thin fibrovascular stroma. The tubules were lined by tumor cells, which had basally located nuclei and abundant eosinophilic and vacuolated cytoplasm. In some areas, the tumor cells were arranged in a retiform growth pattern, mimicking a rete testis/ovarii. Disseminated metastases to the surfaces of the mesentery, spleen and liver were also present. Immunohistochemically, many tumor cells were strongly positive for vimentin, estrogen receptor α and Ki 67. Some tumor cells were positive for pancytokeratin and inhibin α. These findings closely resemble those of an ovarian-derived human malignant Sertoli cell tumor. From our review of the literature, we believe this is the first report of a spontaneous malignant Sertoli cell tumor in the ovary of a young laboratory rat. This case might provide useful historical control information for rat toxicity studies.