A large gastric rupture due to blunt trauma: a case report and a review of the Japanese literature.

Gastric rupture due to blunt trauma is rare, occurring in only 0.07-1.2% of all abdominal blunt traumas. We reported a case with a 10-cm-long hole and review 25 cases in Japan. A 22-year-old man was involved in a traffic accident, 2 h after eating a lot of food. He had suffered muscular defense in the abdomen. An abdominal computed tomography (CT) scan revealed free air, disruption of the gastric wall and a lot of food residue. The laparotomy showed a burst of 10 cm that ran parallel to the long axis from the cardia to the body. A simple closure was primarily performed and drains were placed in the abdominal cavity. The patient was discharged on the 32nd day. Most cases of gastric rupture are diagnosed intraoperatively, but careful evaluation of CT scans and patient interviews are needed to make an accurate preoperative diagnosis.

Therapeutic strategies for head and neck cancer based on p53 status.

Squamous cell carcinomas of the head and neck (HNSCC) are one of the most common types of cancers worldwide, and despite advances in treatment, they still represent a clinical challenge. Inactivation of one or more components in the p53 signaling pathway is an extremely common event in human neoplasia, including HNSCC. The loss of p53 function is responsible for increased aggressiveness in cancers, while tumor chemoresistance and radioresistance can depend on deleted p53 expression, or on the expression of mutated-p53 proteins. Thus, consideration and manipulation of the p53 status during HNSCC cancer therapy should be considered. This review discusses the p53 signaling pathways activated by various cellular stresses, including exposure to cancer therapies. The recognition of the p53 status in cancer cells is a significant factor and could provide valuable assistance during the selection of an effective therapeutic approach.

Depression of p53-independent Akt survival signals in human oral cancer cells bearing mutated p53 gene after exposure to high-LET radiation.

Although mutations and deletions in the p53 tumor suppressor gene lead to resistance to low linear energy transfer (LET) radiation, high-LET radiation efficiently induces cell lethality and apoptosis regardless of the p53 gene status in cancer cells. Recently, it has been suggested that the induction of p53-independent apoptosis takes place through the activation of Caspase-9 which results in the cleavage of Caspase-3 and poly (ADP-ribose) polymerase (PARP). This study was designed to examine if high-LET radiation depresses serine/threonine protein kinase B (PKB, also known as Akt) and Akt-related proteins. Human gingival cancer cells (Ca9-22 cells) harboring a mutated p53 (mp53) gene were irradiated with 2 Gy of X-rays or Fe-ion beams. The cellular contents of Akt-related proteins participating in cell survival signaling were analyzed with Western Blotting 1, 2, 3 and 6h after irradiation. Cell cycle distributions after irradiation were assayed with flow cytometric analysis. Akt-related protein levels decreased when cells were irradiated with high-LET radiation. High-LET radiation increased G(2)/M phase arrests and suppressed the progression of the cell cycle much more efficiently when compared to low-LET radiation. These results suggest that high-LET radiation enhances apoptosis through the activation of Caspase-3 and Caspase-9, and suppresses cell growth by suppressing Akt-related signaling, even in mp53 bearing cancer cells.

siRNA targeted for NBS1 enhances heat sensitivity in human anaplastic thyroid carcinoma cells.

Nijmegen breakage syndrome 1 (NBS1) plays an important role as a key protein in the repair of radiation-induced DNA double strand breaks (DSBs), and the work described here was designed to examine the effect of NBS1 on heat sensitivity for human anaplastic thyroid carcinoma 8305c cells. Cellular heat sensitivity was evaluated with colony formation assays. Apoptosis was detected and quantified with terminal deoxynucleotidyl transferase mediated dUTP nick end labelling (TUNEL) assay and Hoechst33342 staining assay. Heat-induced DSBs were measured with flow cytometry using γH2AX antibodies. The transfection of NBS1-siRNA into cells specifically inhibited the expression of NBS1, and enhanced heat sensitivity and the frequency of apoptosis through caspase pathway. In addition, more frequent γH2AX foci were observed in the NBS1-siRNA transfected cells than in control cells transfected with scrambled siRNA at 24 h after heat treatment with a pan-caspase inhibitor. These results suggest that heat sensitisation might result from NBS1-siRNA mediated suppression of heat-induced DSB repair, indicating that NBS1-siRNA could potentially function as a heat sensitiser for cancer patients.

Repair pathways independent of the Fanconi anemia nuclear core complex play a predominant role in mitigating formaldehyde-induced DNA damage.

The role of the Fanconi anemia (FA) repair pathway for DNA damage induced by formaldehyde was examined in the work described here. The following cell types were used: mouse embryonic fibroblast cell lines FANCA(-/-), FANCC(-/-), FANCA(-/-)C(-/-), FANCD2(-/-) and their parental cells, the Chinese hamster cell lines FANCD1 mutant (mt), FANCGmt, their revertant cells, and the corresponding wild-type (wt) cells. Cell survival rates were determined with colony formation assays after formaldehyde treatment. DNA double strand breaks (DSBs) were detected with an immunocytochemical γH2AX-staining assay. Although the sensitivity of FANCA(-/-), FANCC(-/-) and FANCA(-/-)C(-/-) cells to formaldehyde was comparable to that of proficient cells, FANCD1mt, FANCGmt and FANCD2(-/-) cells were more sensitive to formaldehyde than the corresponding proficient cells. It was found that homologous recombination (HR) repair was induced by formaldehyde. In addition, γH2AX foci in FANCD1mt cells persisted for longer times than in FANCD1wt cells. These findings suggest that formaldehyde-induced DSBs are repaired by HR through the FA repair pathway which is independent of the FA nuclear core complex.

ATM is the predominant kinase involved in the phosphorylation of histone H2AX after heating.

Heating induces histone H2AX phosphorylation at serine 139 (gammaH2AX). Phosphorylated H2AX subsequently forms foci in numerous mammalian cell lines. The aim of this study was to clarify details in the mechanisms involved in the phosphorylation of H2AX after heating. The cell lines used were DNA-PKcs knockout cells, ATM knockout cells, and their parental cell lines. To elucidate mechanisms of induction of phosphorylation of H2AX after heating, ATM/ATR inhibitor (CGK733) and DNA-PK inhibitor (NU7026) were used. The intensity of gammaH2AX signals was assayed with flow cytometry. The thermal dose-response curve for the fluorescence intensity of gammaH2AX appearance in DNA-PKcs-/- cells during the heating period was similar to that observed in DNA-PKcs+/+ cells. On the other hand, the slope of thermal dose-response curve for them in ATM-/- cells was lower than that in ATM+/+ cells. Phosphorylation of H2AX after heating was suppressed by a combination of CGK733 and NU7026 in the culture medium in DNA-PKcs-/- cells, ATM-/- cells and in their parental cells. Although the phosphorylation of H2AX after heating was not suppressed by NU7026 in their parental cells, such phosphorylation was suppressed by CGK733 in their parental cells. These results indicate that ATM is the predominant protein which is active in the phosphorylation of histone H2AX after heating.

Biphasic effects of nitric oxide radicals on radiation-induced lethality and chromosome aberrations in human lung cancer cells carrying different p53 gene status.

PURPOSE: The aim of this study was to clarify the effects of nitric oxide (NO) on radiation-induced cell killing and chromosome aberrations in two human lung cancer cell lines with a different p53 gene status. METHODS AND MATERIALS: We used wild-type (wt) p53 and mutated (m) p53 cell lines that were derived from the human lung cancer H1299 cell line, which is p53 null. The wtp53 and mp53 cell lines were generated by transfection of the appropriate p53 constructs into the parental cells. Cells were pretreated with different concentrations of isosorbide dinitrate (ISDN) (an NO donor) and/or 2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO) (an NO scavenger) and then exposed to X-rays. Cell survival, apoptosis, and chromosome aberrations were scored by use of a colony-forming assay, Hoechst 33342 staining assay and TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP [deoxyuridine triphosphate] nick end labeling) assay, and chromosomal banding techniques, respectively. RESULTS: In wtp53 cells the induction of radioresistance and the inhibition of apoptosis and chromosome aberrations were observed in the presence of ISDN at low 2- to 10-mumol/L concentrations before X-irradiation. The addition of c-PTIO and ISDN into the culture medium 6 h before irradiation almost completely suppressed these effects. However, at high concentrations of ISDN (100-500 mumol/L), clear evidence of radiosensitization, enhancement of apoptosis, and chromosome aberrations was detected. However, these phenomena were not observed in mp53 cells at either concentration range with ISDN. CONCLUSIONS: These results indicate that low and high concentrations of NO radicals can choreograph inverse radiosensitivity, apoptosis, and chromosome aberrations in human lung cancer cells and that NO radicals can affect the fate of wtp53 cells.

siRNA targeting NBS1 or XIAP increases radiation sensitivity of human cancer cells independent of TP53 status.

NBS1 is essential for the repair of radiation-induced DNA double-strand breaks (DSBs) in yeast and higher vertebrate cells. In this study, we examined whether suppressed NBS1 expression by small interference RNA (siRNA) could enhance radiation sensitivity in cancer cells with different TP53 status. We used human non-small cell lung cancer cells differing in TP53 gene status (H1299/wtp53 cells bearing wild-type TP53 or H1299/mp53 cells bearing mutant TP53). A DNA cassette expressing siRNA targeted for the NBS1 gene was transfected into those cell lines, and radiation sensitivity was examined with a colony-forming assay. Cellular levels of NBS1 and other proteins were analyzed using Western blotting. We found that the radiation sensitivity of H1299/wtp53 and H1299/mp53 cells was enhanced by transfection of the DNA cassette. In the NBS1-siRNA-transfected cells, we observed decreased constitutive expression of NBS1 protein and decreased radiation-induced accumulation of phosphorylated NBS1 protein. In addition, radiation-induced expression of the transcription factor NF-kappaB (NFKB) and XIAP (X-chromosome-linked inhibitor of apoptosis protein) was suppressed by NBS1-siRNA. Enhanced X-ray sensitivity after NBS1-siRNA transfection was achieved in TP53 wild-type cells and sensitivity was even more pronounced in TP53 mutant cells. The transfection of siRNA targeted for XIAP also enhanced X-ray sensitivity even more for TP53 mutant cells compared to TP53 wild-type cells. Our data suggest that the sensitization to radiation results from NBS1-siRNA-mediated suppression of DNA repair and/ or X-ray-induced cell survival signaling pathways through NFKB and XIAP. siRNA targeting appears to be a novel radiation-sensitizing agent, particularly in human TP53 mutant cancer cells.

Heat-induced phosphorylation of NBS1 in human skin fibroblast cells.

NBS1 is known to be involved in DNA damage-induced cellular responses after exposure to ionizing radiation (IR). Phosphorylation of NBS1 contributes to cell-cycle checkpoints. The aim of this study was to determine whether heat exposure induces or stimulates cellular responses mediated by the phosphorylation of NBS1 in human skin fibroblast cell lines. The results of immunofluorescent staining and Western blot analysis showed that NBS1 proteins are phosphorylated after exposure to heat in the nucleus of a normal skin fibroblast cell line (82-6 cells). This suggests that the NBS1-mediated signal transduction could be induced by heat. We further examined whether a deficiency in the NBS1 protein modifies heat sensitivity in human skin fibroblast cell lines. A skin fibroblast cell line (Gmtert), derived from a Nijmegen breakage syndrome (NBS) patient containing mutant NBS1, showed higher sensitivity to heat than the same cell line transfected with the wild-type copy of the NBS1 gene. We also showed that transfection of a DNA cassette expressing small interference RNA (siRNA) targeted to NBS1 into 82-6 cells enhanced cell sensitivity to heat. These results suggest that NBS1 is involved in cellular responses to DNA damage which is induced by heat exposure as well as by radiation exposure in human skin fibroblast cells.

The effect of clinorotation on vestibular compensation in upside-down swimming catfish.

Upside-down swimming catfish Synodontis nigriventris can keep upside-down swimming posture stably under pseudo-microgravity generated by clinostat. When the vestibular organ is unilaterally ablated, the operated S. nigriventris shows disturbed swimming postures under the clinorotation condition. However, about 1 month after the operation, unilateral vestibular organ-ablated S. nigriventris shows stable upside-down swimming posture under the condition (vestibular compensation). In contrast, a closely related upside-up swimming catfish Synodontis multipunctatus belonging to same Synodontis family can not keep stable swimming postures under the clinorotation conditions. In this study, we examined the effect of continuous clinorotation on vestibular compensation in intact and unilateral vestibular organ-ablated Synodontis nigriventris and Synodontis multipunctatus. After the exposure to continuous clinorotation, the postures of the catfish were observed under microgravity provided by parabolic flights of an aircraft. Unilateral vestibular organ-ablated S. nigriventris which had been exposed to continuous clinorotation showed stable swimming postures and did not show dorsal light reaction (DLR) under microgravity. This postural control pattern of the operated catfish was similar to that of intact catfish. Intact and unilateral vestibular organ-ablated S. multipunctatus showed DLR during microgravity. Our results confirmed that S. nigriventris has a novel balance sensation which is not affected by microgravity. DLR seems not to play an important role in postural control. It remains unclear that the continuous clinorotation effects on vestibular compensation because we could not keep used unilateral vestibular organ-ablated fish alive under continuous clinorotation for uninterrupted 25 days. This study suggests that space flight experiments are required to explore whether gravity information is essential for vestibular compensation.