Serine/threonine kinase AKT is frequently activated in human bile duct cancer and is associated with increased radioresistance

The prognosis for patients with bile duct cancer (BDC) remains poor. Although BDC cells are essentially radioresistant, recent reports have suggested that radiation therapy, in addition to its palliative role in the management of BDC, may improve patient survival. A better understanding of the mechanisms that lead to cellular radioresistance may assist in the development of more effective BDC therapies based on radiotherapy in combination with radiosensitizing agents. The serine/threonine kinase AKT/protein kinase B, a downstream effector of phosphatidylinositol 3'-kinase, is a well-characterized kinase that is known to play a critical role in antiapoptotic signaling pathways. In this investigation, we sought to clarify the role of AKT signaling in the radioresistance in BDC cells. First, to examine whether activated AKT is expressed in BDCs, tumor specimens were obtained from 19 consecutive BDC cases. Immunohistochemical staining using an anti-phosphorylated-AKT antibody showed that phosphorylated (activated) AKT was expressed in cancer cells but not in neighboring normal mucosa in 16 cases (84.2%). Next, to evaluate the role of AKT activation in the regulation of BDC cell radiosensitivity, clonogenic assays were performed using the phosphatidylinositol 3'-kinase inhibitor LY294002 with and without irradiation. LY294002 inhibited AKT activation in BDC cells and, on irradiation, decreased clonogenic survival in a radiation dose-dependent manner. Only a small decrease in cell viability was observed in cells exposed to LY294002. Expression of constitutively active AKT in BDC cells resulted in decreased radiosensitivity, whereas a dominant-negative AKT increased radiosensitivity. Furthermore, constitutively active AKT also inhibited radiation-induced apoptosis. Collectively, these results indicate that activated AKT in BDC cells is associated with radioresistance and suggest that pharmacological or genetic modulation of AKT activity may have important therapeutic implications in BDC patients treated with radiation.     

Involvement of V(D)J recombinase in the generation of intragenic deletions in the Rit1/Bcl11b tumor suppressor gene in gamma-ray-induced thymic lymphomas and in normal thymus of the mouse

Mouse thymic lymphomas induced by gamma-irradiation exhibited homozygous deletions of the Rit1/Bcl11b tumor suppressor gene on chromosome 12 at high frequencies. Internal deletions of one allele were frequently accompanied by loss of the other allele. In order to elucidate the mechanism of these internal deletions, the sites of breakage and rejoining were examined by PCR mapping and sequencing. The 5' site of the deletions clustered within an approximately 5 kb region of intron 1 and the 3' site was confined to a site in intron 3. These sites contained P and/or N nucleotides and cryptic sequences recognizable by the RAG1/2 recombinase in the vicinity. This suggests that the Rit1 intragenic deletions were generated by endogenous illegitimate V(D)J recombinase activity and such aberrant recombination was also detected by nested PCR of DNA from the thymus of unirradiated mice but not of RAG2-deficient mice. A rough estimate indicated that there reside as many as 10(3)-10(4) thymocytes having Rit1 deletions, assuming the presence of 10(8) thymocytes in the thymus of unirradiated mice. Moreover, the recombination frequency was not affected by gamma-irradiation. These results show no effect of radiation on Rit1 mutations and suggest an indirect mechanism for its role in lymphomagenesis.     

NY-ESO-1 expression and its serum immunoreactivity in esophageal cancer

Purpose NY-ESO-1, a member of the cancer/testis antigen (CTA) family, elicits humoral and cellular immune responses in patients with advanced cancer. Unresectable or metastatic esophageal carcinoma patients do not benefit from the present multimodality treatment regimens in terms of survival. The objectives of this study were to analyze the antibody response to NY-ESO-1 antigen in patients with esophageal cancer and to determine the potential of NY-ESO-1 for use in tumor-specific immunotherapy.Methods Serum from 69 patients with esophageal cancer was investigated for antibody production against NY-ESO-1 by Western blot analysis. Also analyzed by immunohistochemistry were 56 tissue samples from these patients for NY-ESO-1 protein expression.Results NY-ESO-1 protein expression was found in 18 of 56 (32%) esophageal carcinomas. Serum immunoreactivity specific for NY-ESO-1 was found in 9 patients (13%) of whom 8 were in the advanced stage (stages III and IV). There was no relationship between clinicopathologic features and serum immunoreactivity for NY-ESO-1. NY-ESO-1 protein expression was detected in three of five antibody-positive patients whose tissue was available for analysis. Survival analysis showed no significant difference between antibody-positive and antibody-negative patient groups.Conclusions A humoral immune response to NY-ESO-1 antigen was established in patients with advanced esophageal cancer. NY-ESO-1 is a good candidate for vaccine-based immunotherapy for advanced esophageal carcinoma.     

A case of neurosyphilis showing a marked improvement of clinical symptoms and cerebral blood flow on single photon emission computed tomography with quantitative penicillin treatment

A 31-year-old woman manifested significant emotional symptoms and personality change due to neurosyphilis; her clinical symptoms were improved with quantitative penicillin treatment. On admission, magnetic resonance imaging (MRI) showed no abnormal findings, while N-isopropyl-p-[123I] iodoamphetamine single photon emission computed tomography (123I-IMP SPECT) initially showed a remarkable increase in cerebral blood flow (CBF) in the cerebral cortex. This increase disappeared after improvement of the patient's clinical symptoms with treatment. It appears that the increase in CBF might have reflected an active inflammatory state of neurosyphilis and that its disappearance might therefore represent successful treatment with penicillin for neurosyphilis. Our case study suggests that single photon emission computed tomography (SPECT) is a useful method for evaluating an inflammatory state and for assessing the effect of therapy on neurosyphilis.     

Overexpression of glyceraldehyde-3-phospahe dehydrogenase is not involved in 5-hydroxytryptamine (5-HT)-induced necrosis in cultured cerebrocortical neurons

Cerebrocortical cell cultures were prepared from 1-d-old rats. On post-culture day 6, 5-hydroxytryptamine (5-HT) was added to the medium and cells were exposed for another 3 d. 5-HT elicited cytotoxicity in a dose-dependent manner, and the survival rate of neuronal cells was decreased to 64.9+/-5.0% at 0.1 mM concentration. Chromatin staining with Hoechst 33258 and electron microscopy revealed that the 5-HT-induced neuronal death was entirely due to necrosis. Pretreatments with glyceraldehyde-3-phosphate dehydrogenase (GAPDH) antisense oligonucleotide and several classical apoptotic inhibitors did not exhibit neuroprotection in this paradigm. Northern blot analysis showed that the enhancement of GAPDH mRNA levels was undetected during cell death. The present results demonstrate that GAPDH overexpression is not involved in the 5-HT-induced necrotic death pathway.     

Cholangiographic criteria for anomalous union of the pancreatic and biliary ducts

BACKGROUND: Anomalous union of the pancreatic and biliary ducts (AUPBD) is characterized by the intersection of these ducts proximal to the sphincter of Oddi. Thus, the relative anatomic relationship between the pancreaticobiliary ductal union and the narrow distal segment of the bile duct, which represents the functional sphincter, on cholangiopancreatograms determines whether the ductal union is normal or anomalous. This study examined whether the length of the common channel or that of the narrow distal segment is more closely associated with AUPBD and defined radiographic criteria for AUPBD. METHODS: The length of the common channel and of the narrow distal segment were measured directly on cholangiopancreatograms from 350 patients. RESULTS: AUPBD was found in 36 patients (10%). The common channel was significantly longer in patients with AUPBD (p < 0.001), whereas the length of the narrow distal segment was comparable between patients with and without AUPBD (p = 0.38). There was considerable overlap in the range of the length of the common channel between patients with and without AUPBD. CONCLUSIONS: The length of the common channel is closely associated with the presence of AUPBD. However, a diagnosis of AUPBD based on the length of the common channel is not reliable. The diagnosis of AUPBD continues to rely on the radiographic criterion of a pancreaticobiliary ductal union located proximal to the narrow distal segment, which represents the sphincter of Oddi.     

Influence of patient variables and sensor location on regional cerebral oxygen saturation measured by INVOS 4100 near-infrared spectrophotometers

Cerebral oximeter based on near-infrared spectroscopy has been used as a continuous, noninvasive monitoring of regional cerebral oxygen saturation (rSO2). Although the absolute rSO2 values have a wide range of variability, the factors affecting a variability of rSO2 values have not been extensively investigated. The authors investigated the influence of patient variables and sensor location on rSO2 measured by the cerebral oximeter INVOS 4100 in 111 patients anesthetized with sevoflurane, fentanyl, and nitrous oxide in oxygen. The sensors for rSO2 measurements were applied on the right forehead (R), 1 cm lateral to R (R1), on the left forehead (L), 1 cm lateral to L (L1), and on the center of the forehead (C). The relationship between the rSO2 values and patient variables were also analyzed. Values of rSO2 at R1 and L1 were significantly lower than those at R and L, respectively. Values of rSO2 at C were significantly higher compared with those at other sites. There were no significant correlations between the rSO2 values and values of weight, height, and head size. Values of rSO2 were similar between males and females. A significant negative correlation between the rSO2 values and age and a positive correlation between the rSO2 values and hemoglobin concentration were observed. These data indicate that patient age, hemoglobin concentration at the measurement, and sensor location can affect rSO2 values.