Different Roles of 8-Hydroxyguanine Formation and 2-Thiobarbituric Acid-reacting Substance Generation in the Early Phase of Liver Carcinogenesis Induced by a Choline-deficient, l-Amino Acid-defined Diet in Rats

The present study was performed to assess the roles of hepatocellular oxidative damage to DNA and constituents other than DNA in rat liver carcinogenesis caused by a choline-deficient, l -amino acid-defined (CDAA) diet by examining the effects of the antioxidant N, N' -diphenyl- p -phenylenediamine (DPPD). The parameters used for cellular oxidative damage were the level of 8-hydroxyguanine (8-OHGua) for DNA and that of 2-thiobarbituric acid-reacting substance (TBARS) for constituents other than DNA. A total of 40 male Fischer 344 rats, 6 weeks old, were fed the CDAA diet for 12 weeks with or without DPPD (0.05, 0.10 or 0.20%) or butylated hydroxytoluene (BHT, 0.25%). In the livers of the rats, the numbers and sizes of glutathione S -transferasc (EC 2.5.1.18) placental form (GSTP)- and/or γ-glutamyltransferase (GGT, EC 2.3.2.2)-positive lesions and levels of 8-OHGua and TBARS were determined. The GSTP-positive lesions of 0.08 mm² or larger were all stained positively for GGT as well in cross-sectional area, whereas the smaller lesions were generally negative for GGT. DPPD and BHT reduced the size of the GSTP-positive lesions without affecting their total numbers. At the same time, they reduced TBARS generation without affecting 8-OHGua formation in DNA. The present results indicate that oxidative DNA damage (represented by 8-OHGua formation) and damage to constituents other than DNA (represented by TBARS generation) may play different roles in rat liver carcinogenesis caused by the CDAA diet; the former appears to be involved in the induction of phenotypically altered hepatocyte populations while the latter may be related to the growth of such populations.     

Initiation of hepatocarcinogenesis by endogenously formed N-nitrosobis(2-hydroxypropyl)amine, N-nitrosodiethanolamine and N-nitroso-2,6-dimethylmorpholine in rats

Initiation activities of endogenously formed N-nitrosobis(2-hydroxypropyl)amine(NBHPA), N-nitrosodiethanolamine (NDELA) and N-nitroso-2,6-dimethylmorpholine(NDMM) were investigated in a modified short-term assay forrat hepatocarcinogenesis. Male Wistar rats were fed 1 % bis(2-hydroxypropyl)amine,0.5% diethanolamine or 0.25% 2,6-dimethylmorpholine in the dietplus 0.3% sodium nitrite in the drinking water. Two weeks afterstarting the experimental regimen they underwent 2/3 partialhepatectomy and were then maintained on the respective dietsfor a further week. Following a 2 week recovery period on basaldiet the rats were subjected to a resistant hepatocyte regimenconsisting of 0.02% 2-acetylaminofluorene in the diet for 2weeks and 1 mg carbon tetrachloride/kg body wt by gavage atthe midpoint. Initiation activity was assayed by measuring hepaticfoci positive for     

A case of aneurysmal subarachnoid hemorrhage associated with bilateral common carotid artery occlusion

Cerebral aneurysm may occur in some cases of major cerebral artery occlusion. However, according to our search of the literature, only four cases of aneurysmal subarchnoid hemorrhage (SAH) associated with bilateral common carotid artery occlusion (CCAO) have been reported in addition to the case we report here with a summary of the previously reported cases. A healthy 82-year-old female was found unconscious and admitted to our hospital where her neurological state was diagnosed as Hunt & Kosnik grade II, World Federation of Neurosurgical Societies grade II. General physical examination yielded no abnormal findings. A computed tomography (CT) scan of the head revealed a subarachnoid hemorrhage (Fisher's classification group 3). An aortogram demonstrated the presence of both vertebral arteries (VA), but the origins of the common carotid arteries (CCAS) were not visible at all. The left vertebral angiogram (VAG) revealed anastomosis between the muscle branch of the VA and the occipital artery, with retrograde blood flow through the external carotid artery supplying the internal carotid artery (ICA). These findings were also visible on the right VAG, but there was severe stenosis of the C2 portion of the right ICA. The right enlarged posterior communicating artery (Pcom) supplied the right ICA. Two saccular aneurysms arising from the junction of the right posterior cerebral artery (PCA) and the enlarged right Pcom and the P2 segment of right PCA, respectively were also observed. Aneurysm formation in this case was probably caused by hemodynamic stress secondary to bilateral CCAO induced by arteriosclerosis.     

Effects of mild hypothermia and alkalizing agents on brain injuries in rats with acute subdural hematomas

Brain ischemia is the leading pathopysiological mechanism in the development of secondary brain damage after acute subdural hematoma (SDH). Hypothermia has been employed as an effective cerebroprotective treatment on brain injuries, but the control of the general condition is very difficult under hypothermia, and various severe complications have been reported. Cerebral acidosis in the ischemic area is one of the important factors augmenting the brain edema formation. Tris-(hydroxymethyl)-aminomethane (THAM) has been used as an alkalizing agent for acidosis on brain injury and is reported to be effective. In the present study, we used a rat acute SDH model to assess the effect of mild (35 degrees C) hypothermia and THAM combined treatment on brain water content, brain ischemia, and blood-brain barrier (BBB) permeability at 4 h after hematoma induction. Mild hypothermia did not significantly reduce the brain water content beneath the hematoma (79.5 +/- 0.2%) compared to normothermia (80.2 +/- 0.2%), but mild hypothermia combined to THAM resulted in a significant reduction (78.7 +/- 0.0%; p < 0.01). Combined with mild hypothermia, THAM treatment significantly reduced the Evan's blue extravasation (35 +/- 7 ng/g wet tissue; p < 0.05) compared to normothermia (63 +/- 7 ng/g wet tissue). Furthermore, the volume of infarction at 24 h after the hematoma induction (54 +/- 3 mm(3); p < 0.01) was significantly smaller by the combined treatment compared with normothermia (70 +/- 2 mm(3)). The present findings indicate that mild hypothermia of 35 degrees C combined with THAM presents a potent cerebroprotective strategy. The protection of the BBB is one of the possible cerebroprotective mechanisms in this rat acute SDH model.     

Solitary Intraperitoneal Recurrence of α-Fetoprotein-Producing Gastric Carcinoma: Report of a Case

Abstact A solitary recurrence of gastric carcinoma in the peritoneal cavity is extremely rare. We herein present a case of solitary intraperitoneal recurrence in a patient with α-fetoprotein (AFP)-producing gastric carcinoma. As far as we can determine, this is the first report of such a form of recurrence in a patient with gastric carcinoma who underwent a successful resection. A review of our eight patients who had AFP-producing gastric carcinoma showed a frequent association with hepatic metastasis and a poor prognosis as has been reported previously. Our patient received intra-arterial chemotherapy with low-dose cisplatin and 5-fluorouracil to prevent hepatic recurrence, but eventually developed multiple hepatic metastases after ceasing this therapy. Therefore, adjuvant intra-arterial chemotherapy may have altered the site of first recurrence in this patient. Received: June 6, 2001 / Accepted: November 20, 2001     

ABCA4 gene mutations in Japanese patients with Stargardt disease and retinitis pigmentosa

PURPOSE: To evaluate photoreceptor cell-specific adenosine triphosphate (ATP)-binding cassette transporter (ABCA4) gene mutations in Japanese patients with Stargardt disease (STGD) and the correlation of these mutations to clinical phenotypes. METHODS: Serum was obtained from 10 unrelated Japanese patients with STGD and 96 unrelated Japanese patients with autosomal recessive retinitis pigmentosa (arRP). All 50 ABCA4 gene exons of the patients with STGD were screened for mutations by a combination of single-strand conformation polymorphism analysis and polymerase chain reaction (PCR) direct-sequencing techniques. By restriction enzyme digestion, primer extension analysis, and PCR direct sequencing techniques, the patients with arRP were screened for three segregated, presumably null ABCA4 gene mutations observed in Japanese patients with STGD. RESULTS: Three novel, presumably null mutations of the ABCA4 gene, IVS7-45_952delinsTCTGACC, IVS12+2T-->G, and 1894delA, were identified. The Arg2149stop mutation that had been found in a white patient with STGD in a prior study was also found in a Japanese patient. Two arRP-affected siblings and two unrelated patients with STGD were found to be homozygous for the same IVS12+2T-->G mutation, and three other arRP-affected siblings were carriers of the IVS12+2T-->G mutation and/or the IVS7-45_952delinsTCTGACC mutation. These three siblings with arRP showed only atrophic degeneration in the macula early after the onset of the disease, and STGD had been diagnosed. CONCLUSIONS: Three novel ABCA4 gene mutations were identified in Japanese patients with STGD and arRP. Mutations in the ABCA4 gene can cause panretinal degeneration that changes its clinical appearance from STGD to arRP over time.     

Apoptosis and microglial activation in influenza encephalopathy

During influenza epidemics in Japan, the number of children with acute encephalopathies and encephalitis has recently increased. Although the pathophysiologies remain unclear, there is usually brain edema with evidence of damage to the blood-brain-barrier (BBB). We investigated the glial reaction and apoptosis in brains of eight such cases comprising two of acute necrotizing encephalopathy and six of influenza encephalopathy, and compared the results with those in five control brains. Apoptosis, evidenced by chromatin condensation and fragmentation in hematoxylin sections, in situ end labeling of fragmented DNA (TUNEL) and DNA laddering, was observed in neurons and glial cells in four brains with influenza encephalopathy. In the TUNEL-positive brains, the increase in microglia was greater than in the TUNEL-negative brains. Immunoreactivity for active-caspase 3, demonstrated by immunohistochemistry, and the overexpression of a caspase-cleaved fragment of poly(ADP-ribose) polymerase, demonstrated by Western blotting, indicated that activation of caspase 3 is involved in the apoptotic pathway in the brains of influenza encephalopathy cases. Apoptosis or specific pathological processes that cause apoptosis may give rise to aggravated encephalopathy.     

Nestin expression after experimental intracerebral hemorrhage

The current study examines nestin expression after intracerebral hemorrhage (ICH), the role of different blood components in nestin upregulation, and the possibility that low doses of thrombin that induce tolerance to brain injury (thrombin preconditioning) might also induce nestin expression. Adult male Sprague-Dawley rats received an intracaudate injection of either whole blood, thrombin (1 or 5 U) or red blood cells (RBCs). Animals were sacrificed for single and double labeling immunohistochemistry to identify which cells express nestin, and for Western blotting to quantify nestin expression. By immunohistochemistry, nestin immunoreactivity was present in large numbers of astrocytes, surrounding the hematoma from day 3 to 1 week after ICH. After 2 weeks, nestin immunoreactivity was co-localized with a neuronal marker (neuronal specific enolase). By Western blot analysis, nestin was strongly expressed at day 3 (P<0.01) and 1 week (P<0.01), and expression persisted for at least 1 month (P<0.05). Intracerebral injection of thrombin or lysed RBCs resulted in a marked increase in nestin expression. Interestingly, injection of a low dose of thrombin that induces brain tolerance also upregulated nestin. The ICH-induced nestin expression in astrocytes may reflect an early response of these cells to injury, while the delayed expression in neurons might be a part of the adaptative response to injury perhaps leading to recovery of function. Nestin induction by a low dose of thrombin suggests that specific receptor-mediated pathways are involved in inducing nestin expression and that nestin may play a role in thrombin preconditioning.