Multiple nodules on the face and in the nasal cavity are the symptoms of vegetative pyoderma gangrenosum complicated with myelodysplastic syndrome

We have encountered and treated an unusual case of pyoderma gangrenosum (PG) characterized by multiple nodular lesions on the face and in the nasal meatus, which was complicated by myelodysplastic syndrome.

Weil's disease with elevated plasma D-dimer

We report a case of Weil's disease manifesting elevation of plasma D-dimer in the acute phase. Later, in the convalescent phase after treatment, the plasma levels of D-dimer returned to normal. Plasma D-dimer can be used as a marker of fibrin formation and degradation. Based on our observations, we conjecture that fibrin formation and fibrinolysis may occur in the acute phase of Weil's disease.

Discovery of a cool planet of 5.5 Earth masses through gravitational microlensing

In the favoured core-accretion model of formation of planetary systems, solid planetesimals accumulate to build up planetary cores, which then accrete nebular gas if they are sufficiently massive. Around M-dwarf stars (the most common stars in our Galaxy), this model favours the formation of Earth-mass (M(o)) to Neptune-mass planets with orbital radii of 1 to 10 astronomical units (au), which is consistent with the small number of gas giant planets known to orbit M-dwarf host stars. More than 170 extrasolar planets have been discovered with a wide range of masses and orbital periods, but planets of Neptune's mass or less have not hitherto been detected at separations of more than 0.15 au from normal stars. Here we report the discovery of a 5.5(+5.5)(-2.7) M(o) planetary companion at a separation of 2.6+1.5-0.6 au from a 0.22+0.21-0.11 M(o) M-dwarf star, where M(o) refers to a solar mass. (We propose to name it OGLE-2005-BLG-390Lb, indicating a planetary mass companion to the lens star of the microlensing event.) The mass is lower than that of GJ876d (ref. 5), although the error bars overlap. Our detection suggests that such cool, sub-Neptune-mass planets may be more common than gas giant planets, as predicted by the core accretion theory.

Association between IL-18 gene promoter polymorphisms and inflammatory bowel disease in a Japanese population

BACKGROUND

Interleukin-18 (IL-18) is a pleiotropic cytokine that induces the production of interferon (IFN)-gamma and also to regulate Th2 cytokines. Recently, association studies between IL-18 gene promoter polymorphisms and several Th1- or Th2-mediated inflammatory diseases were reported. In inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), recent evidence suggests that IL-18 is involved in the pathogenesis.

METHODS

Using DNA direct sequencing, we investigated IL-18 gene promoter polymorphisms at -607C/A and -137G/C. Allele, genotype, and haplotype frequencies were determined in 210 Japanese patients with UC, 205 patients with CD, and 212 controls.

RESULTS

In UC, the -137C allele frequency was significantly higher in the proctitis-type patients than in controls (Pc = 0.0068). The -137 genotype frequency was also significantly different in the proctitis-type patients than in controls (Pc = 0.032). No other allele and genotype frequencies were significantly associated with UC after Bonferroni correction. Furthermore, the frequency of haplotype 2 (-607A, -137C), which had a lower promoter activity and IFN-gamma mRNA level than the other haplotypes as previously reported, was significantly higher in the proctitis-type patients than in controls (Pc = 0.01). In CD, we could not find any significant differences.

CONCLUSIONS

IL-18 gene promoter polymorphisms may not be associated with disease susceptibility but related to the extent of disease in UC.

Efficacy of gemtuzumab ozogamicin on ATRA- and arsenic-resistant acute promyelocytic leukemia (APL) cells

Acute promyelocytic leukemia (APL) cells express a considerable level of CD33, which is a target of gemtuzumab ozogamicin (GO), and a significantly lower level of P-glycoprotein (P-gp). In this study, we examined whether GO was effective on all-trans retinoic acid (ATRA)- or arsenic trioxide (ATO)-resistant APL cells. Cells used were an APL cell line in which P-gp was undetectable (NB4), ATRA-resistant NB4 (NB4/RA), NB4 and NB4/RA that had been transfected with MDR-1 cDNA (NB4/MDR and NB4/RA/MDR, respectively), ATO-resistant NB4 (NB4/As) and blast cells from eight patients with clinically ATRA-resistant APL including two patients with ATRA- and ATO-resistant APL. The efficacy of GO was analyzed by (3)H-thymidine incorporation, the dye exclusion test and cell cycle distribution. GO suppressed the growth of NB4, NB4/RA and NB4/As cells in a dose-dependent manner. GO increased the percentage of hypodiploid cells significantly in NB4, NB4/RA and NB4/As cells, and by a limited degree in NB4/MDR and NB4/RA/MDR cells. Similar results were obtained using blast cells from the patients with APL. GO is effective against ATRA- or ATO-resistant APL cells that do not express P-gp, and the mechanism of resistance to GO is not related to the mechanism of resistance to ATRA or ATO in APL cells. Leukemia (2005) 19, 1306-1311. doi:10.1038/sj.leu.2403807; published online 26 May 2005.

Selective granulocyte and monocyte apheresis as a new adjunct to enhance the efficacy of interferon-alpha + ribavirin in patients with high plasma hepatitis C virus

BACKGROUND AND AIM

Selective granulocyte and monocyte/macrophage adsorptive apheresis is to increase the turnover of infected leucocytes and has increased CD4+ T cells, which are necessary for actions of interferon-alpha on hepatitis C virus. Therefore, granulocyte and monocyte apheresis was to enhance the efficacy of interferon + ribavirin.

METHODS

Fifteen patients, 12 had interferon resistant hepatitis C virus and 3 were interferon naive. Hepatitis C virus genotype was 1b in 11 and 2a in 4. The mean plasma HCV-RNA was 728.3 kU/mL and alanine aminotransferase was 107.5 U/L. Granulocyte and monocyte apheresis was with the Adacolumn, which contains carriers that adsorb granulocytes and monocytes/macrophages. After five consecutive granulocyte and monocyte apheresis sessions over 5 days, interferon daily 6 million units for 4 weeks, then three times/week for 20 weeks+ribavirin (600-800 mg per patient per day) were given and followed for another 24 weeks.

RESULTS

During granulocyte and monocyte apheresis, plasma HCV-RNA transiently fell by up to 55%. Similarly, incubation of blood with the Adacolumn carriers caused a significant fall in HCV-RNA. Four patients were unavailable for efficacy evaluation. In the other 11, alanine aminotransferase normalised and at 11 weeks, plasma HCV-RNA was negative; six of these (55%) maintained their remission during the follow up.

CONCLUSION

Granulocyte and monocyte apheresis appears to deplete extra-hepatic hepatitis C virus reservoirs and generate active complement opsonins, which contribute to hepatitis C virus killing. Additional mechanism(s) are also likely and need to be elucidated in future studies with larger cohort of patients.

SUMO-1 modification of the major immediate-early (IE) 1 and 2 proteins of human cytomegalovirus is regulated by different mechanisms and modulates the intracellular localization of the IE1, but not IE2, protein

We have previously shown that two proteins with apparent molecular masses of 91- and 102-kDa (p91 and p102, respectively) in human cytomegalovirus (HCMV)-infected cells are antigenically and structurally related to the major immediate-early (IE) 1 and 2 proteins (IE1p68 and IE2p80, respectively) of HCMV, respectively. In this study, we extended the characterization of p91 and p102 and our results were as follows; (i) Lysine at amino acid position 450 in IE1p68 and at amino acid position 175 or 180 in IE2p80, to which SUMO-1 has been shown to be covalently linked, are required for production of p91 and p102, respectively. (ii) A reversal of cycloheximide (CH) block in the presence of actinomycin D imposed at the time of infection inhibited production of p91, but not p102. (iii) The steady-state levels of p91, but not p102, were remarkably decreased by treatment with proteasome inhibitor MG132, but coincubation with CH inhibited this decrease of p91. (iv) Cell fractionation by differential detergent extraction demonstrated that p91 is preferentially found in detergent-insoluble fraction, although p102 as well as IE1p68 and IE2p80 distributes into all fractions. These results demonstrate that p91 and p102 correspond to SUMO-1-modified IE1p68 and IE2p80, respectively, that the production and degradation of SUMO-1-modified IE1p68 is regulated by mechanisms different from those of SUMO-1-modified IE2p80, and that SUMO-1 modification modulates the intracellular localization of IE1p68, but not IE2p80.

Immunomodulatory effects of selective leucocytapheresis as a new adjunct to interferon-alpha2b plus ribavirin combination therapy: a prospective study in patients with high plasma HCV viraemia

Efficacy of interferon-alpha2b (IFN) + ribavirin (IFN/RBV) combination in patients with high plasma hepatitis C virus (HCV) is very poor. Dysregulated CD4+ /CD8+ T cells is involved in both impaired cell-mediated immunity and resistance to IFN. Adsorptive granulocytes and monocytes apheresis (GMA) can remove infected leucocytes which are extrahepatic HCV reservoirs and also has been associated with intriguing immunomodulation and increases in CD4+ T cells. Our aim was to see if GMA enhances the efficacy of IFN/RBV. Twenty-four patients, 13 IFN resistant and 11 IFN naive were enrolled. Seventeen were genotype 1b and 7 were 2a or 2b. Mean plasma HCV-RNA was 612.9 (100-850) kIU/mL and alanine aminotransferase, 108 (41-373) U/L. GMA was performed with Adacolumn at one session/day for five consecutive days and IFN/RBV was started within 24 h after the last GMA session. Daily 6 million units of IFN, six times/week for 2 weeks and then three times/week for 22 weeks were given with RBV (600-800 mg/day/patient). Patients were followed for 6 months. GMA was associated with a significant increase in lymphocyte counts, complement activation fragment C3a and falls in tissue necrosis factor-alpha, and IL-8 produced by peripheral blood leucocytes. At week 24, 20 of 24 patients (83%) were HCV negative and by end of follow-up (week 49), the remission was sustained in 14 of 24 patients (58%) including 100% of patients with 2a or 2b. In conclusion, enhanced efficacy of IFN/RBV following GMA might be attributed to a more efficient immune function and a renewed IFN signaling towards HCV.

Anterior decompression and fusion for multiple thoracic disc herniation

Multiple thoracic disc herniations are rare and there are few reports in the literature. Between December 1998 and July 2002, we operated on 12 patients with multiple thoracic disc herniations. All underwent an anterior decompression and fusion through a transthoracic approach. The clinical outcomes were assessed using the Frankel neurological classification and the Japanese Orthopaedic Association (JOA) score. Under the Frankel classification, two patients improved by two grades (C to E), one patient improved by one grade (C to D), while nine patients who had been classified as grade D did not change. The JOA scores improved significantly after surgery with a mean recovery rate of 44.8% +/- 24.5%. Overall, clinical outcomes were excellent in two patients, good in two, fair in six and unchanged in two. Our results indicate that anterior decompression and fusion for multiple thoracic disc herniations through a transthoracic approach can provide satisfactory results.

Inverted repeat of a large segment unveiled on the right arm ofSaccharomyces cerevisiae chromosome II

By means of gene disruption analyses, Saccharomyces cerevisiae strain YPH499 was shown to have two, and only two, copies of ATP3 that encodes the gamma-subunit of H+-dependent ATP synthase and locates on the right arm of chromosome II. Linkage analyses of the two distinguishably marked copies of ATP3 indicated that the distance between them was about 43 cM. Since YBR030W, an ORF proximal to ATP3 by a distance of 17 kbp, was also found to be duplicated, we marked them with two distinguishable nutritional markers, which were also distinguishable from those used for marking the two copies of ATP3, and achieved four-point linkage analyses; CEN2 marked with an appropriate nutritional marker gene was included as a reference point. And, the following linkage map was deduced: CEN2- [11 cM]-YBR030Wa- [8 cM]-ATP3a-[47 cM]-ATP3b- [55 cM]-YBR030Wb. From this map, we suspected that a segment spanning at least YBR030W-ATP3 would be inversely duplicated on the right arm of chromosome II. We then carried out chromosome fragmentation analyses, using several laboratory strains including YPH499, and obtained data in accord with our speculation for all strains, although the distance between the two copies of ATP3 varied from 48 kbp to 192 kbp among the strains examined.

Sensitization by glycerol for CDDP-therapy against human cultured cancer cells and tumors bearing mutated p53 gene

To clarify effective chemotherapeutic regimens against cancer, we examined the effects of glycerol on apoptosis induced by CDDP treatment using cultured human cancer cells (in vitro) and transplanted tumor in mice (in vivo). Human tongue cell carcinoma (SAS) cells transfected with mutated p53 gene (SAS/m p53) showed CDDP-resistance compared with the cells with neo control gene (SAS/ neo). When those cultured cells were pre-treated with glycerol, CDDP-induced apoptosis was enhanced by glycerol in SAS/m p53 cells but not in SAS/ neo cells. In tumor-transplanted mice, the glycerol treatment to tumors enhanced growth delay induced by CDDP in mp53 tumors transplanted with SAS/m p53 cells, but not in wtp53 tumors transplanted with SAS/ neo cells. When transplanted tumors were treated with CDDP alone, the cells positive for active caspase-3, 85 kDa PARP and apoptosis were observed by immunohistochemical staining in wtp53 tumors but not in mp53 tumors. When the tumors were treated with CDDP combined with glycerol, positive cells were observed not only in wtp53 tumors but also in mp53 tumors. These results showed that the CDDP-induced growth inhibition of the tumors is p53 -dependent and that the enhanced growth delay by glycerol may be due to the increased apoptosis. Glycerol might be available for cancer chemotherapy in patients with mp53 tumors.

Effects of a heat shock protein inhibitor KNK437 on heat sensitivity and heat tolerance in human squamous cell carcinoma cell lines differing in p53 status

PURPOSE

The effects of a heat shock protein (hsp) inhibitor KNK437 (N-formyl-3,4-methylenedioxy-benzylidene-gamma-butyrolactam) were examined on the heat sensitivity and heat tolerance of human cancer cells with special reference to p53 status.

MATERIALS AND METHODS

Human squamous cell carcinoma (SAS) and glioblastoma cell lines (A-172) transfected with mutant p53 (mp53) or control neo genes were used. KNK437 was added in culture medium at a final concentration of 50, 100 or 300 microM 1 h before heating (42 degrees C). Surviving fractions of cells were measured by use of a clonogenic assay. Effects of KNK437 on the accumulation of heat shock proteins and DNA binding activity of heat shock factor 1 were examined with Western blot analysis and gel mobility-shift assay, respectively. Heat-induced apoptotic bodies were detected by Hoechst 33342 staining.

RESULTS

The mp53-transfected SAS (SAS/mp53) and A-172 (A-172/mp53) cells were more resistant to heat than the neomycin (neo)-transfected SAS (SAS/neo) and A-172 (A-172/neo) cells. The constitutive amount of hsp27 was larger in SAS/mp53 than in SAS/neo cells. Clear differences in the constitutive amounts of hsp40, hsp72 and hsp90 were not observed between SAS/mp53 and SAS/neo cells. KNK437 enhanced the heat sensitivity in SAS/mp53 and A-172/mp53 cells more effectively than in neo control cells. Heat tolerance was suppressed by KNK437 in SAS/mp53 and SAS/neo cells and also in A-172/mp53 and A-172/neo cells. Along with suppression of heat tolerance, KNK437 suppressed heat-induced accumulation of both hsp27 and hsp72. Heat-induced apoptotic bodies were enhanced by KNK437 in SAS/mp53 and SAS/neo cells.

CONCLUSION

The results suggest a possible mechanism for the heat sensitivity of SAS cells. Heat sensitivity depends on p53 status regulating the amount of hsp27. Heat tolerance is suppressed by KNK437 through the suppression of heat-induced accumulations of hsp27 and hsp72 and the induction of p53-independent apoptosis.

C-terminal peptides of p53 molecules enhance radiation-induced apoptosis in human mutant p53 cancer cells

We propose here a novel p53-targeting radio-cancer therapy using p53 C-terminal peptides for patients having mutated p53. Hoechst 33342 staining showed that X-ray irradiation alone efficiently induced apoptotic bodies in wild-type p53 (wt p53) human head and neck cancer cells transfected with a neo control vector (SAS/neo cells), but hardly induced apoptotic bodies in mutation-type p53 (m p53) cells transfected with a vector carrying the m p53 gene (SAS/m p53). In contrast, transfection of p53 C-terminal peptides (amino acid residues 361-382 or 353-374) via liposomes caused a remarkable increase of apoptotic bodies in X-ray-irradiated SAS/m p53 cells, but did not enhance apoptotic bodies in X-ray-irradiated SAS/neo cells. In immunocytochemical analysis, positively stained cells for active type caspase-3 were observed at high frequency after X-ray irradiation in the SAS/m p53 cells pre-treated with p53 C-terminal peptides. In SAS/neo cells, positively stained cells for active type caspase-3 were observed with X-ray irradiation alone. Furthermore, protein extracts from X-ray-irradiated SAS/m p53 cells showed higher DNA-binding activity of p53 to p53 consensus sequence when supplemented in vitro with p53 C-terminal peptides than extracts from non-irradiated SAS/m p53 cells. These results suggest that radiation treatment in the presence of p53 C-terminal peptides is more effective for inducing p53 -mediated apoptosis than radiation treatment alone or p53 C-terminal peptide treatment alone, especially in m p53 cancer cells. This novel tool for enhancement of apoptosis induction in m p53 cells might be useful for p53-targeted radio-cancer therapy.

Heat-induced growth inhibition and apoptosis in transplanted human head and neck squamous cell carcinomas with different status of p53

To examine p53-dependency in hyperthermic cancer therapy, heat-induced growth inhibition and apoptosis in transplanted human head and neck squamous cell carcinoma (HNSCC) tumours were analysed with different status of p53 into nude mice. The tumour tissue from HNSCC cell line (SAS) transfected with mutant p53 gene (SAS/mp53) or control vector containing neo gene (SAS/neo) was transplanted into the subcutaneous tissue of the thigh of nude mice using a trocar. Hyperthermia was performed at 42 degrees C when the mean diameter of tumour was 5-6mm. The diameter of tumours was measured using vernier calipers and tumour weight (TW) and the relative tumour weight (RW) was calculated. Tumour regrowth delay was evaluated when the RW reached 5-fold against the control group. The accumulation of p53 and Bax proteins was examined by an immunohistochemical technique. Apoptotic cells in the sections were detected by staining of DNA ends using an immunohistochemical technique. SAS/mp53 tumours showed more heat-resistance than SAS/neo tumours. The p53-positively staining cells were observed in untreated SAS/mp53 tumours, but not in untreated SAS/neo tumours. After heat treatment, the accumulation of p53 and Bax proteins was observed in SAS/neo tumours, but little in SAS/mp53 tumours. The incidence of apoptotic cells induced by heat treatment was very low in SAS/mp53 tumours compared with SAS/neo tumours. In conclusion, the heat-induced growth inhibition of a transplanted HNSCC may be correlated with the induction of p53-dependent Bax-mediated apoptosis. Thus, p53 status appears to be one of the useful parameters for the predictive assays in hyperthermic cancer therapy.

Topographical and cytopathological lesion analysis of the white matter in Binswanger's disease brains

The purpose of the present study was to document the topographical and cytopathological lesions in the white matter (WM) of Binswanger's disease (BD) brains. Subcortical WM lesions in each lobe and fiber bundle lesions related to the medial thalamic and hippocampal structures in clinicopathologically proven BD brains were evaluated by Klüver-Barrera staining using a grading score. Lesions in the frontal subcortical WM of BD brains, brains from non-neurological patients, and brains with cerebral hemorrhage or large cortical infarcts were also examined immunohistochemically using molecular markers for axonal flow damage: amyloid precursor protein (APP); and for demyelinating axonopathy: encephalitogenic peptide (EP). Our results indicated that the WM lesions in BD were significantly more prominent in the frontal periventricular and subcortical regions as compared with other subcortical WM lesions, in the order of the parietal, occipital and temporal lobes. Fiber bundle lesions in the capsular genu, including the anterior thalamic peduncle, were also significantly more prominent in BD brains as compared with the other bundle lesions. Furthermore, the frequency of damaged nerve fibers labeled by the EP antiserum and APP immunoreactive fibers was significantly higher in BD brains as compared with the control brains. The grading scores for the WM damage correlated significantly with those for the APP and EP immunoreactive fibers in all brains, including the control brains. The axonal damage in the frontal WM lesions of the BD brains was clearly revealed in our study using immunohistochemistry for APP and EP.

Present characteristics of symptomatic Entamoeba histolytica infection in the big cities of Japan

Medical records, for 2000 and 2001, of symptomatic amoebic patients who were treated at our hospitals in Tokyo, Yokohama and Osaka were studied retrospectively for the purpose of gathering epidemiological data on symptomatic Entamoeba histolytica infection. A total of 58 patients were treated. Fifty-five of them were male, and 96% of the male patients were Japanese. The mean age of patients was 44.9 years old, and 91% of patients contracted the disease in Japan. Fifty-six per cent of the male patients indicated that they were practising homosexuals, and 44% of the male patients denied these practices or left the question unanswered. The serum Treponema pallidum haemagglutination test was positive in 45% of the patients, and antibody to human immunodeficiency virus (HIV) was positive in 45%. Our study revealed that recent symptomatic E. histolytica infection almost exclusively afflicted middle-aged males in the big cities of Japan, that a majority of the patients were probably exposed to the causative organism during homosexual activity, and that an increasing number of patients will be co-infected with HIV.

Purification and characterization of the flagellar basal body of Rhodobacter sphaeroides

Flagellar hook-basal body (HBB) complexes were purified from Rhodobacter sphaeroides. The HBB was more acid labile but more heat stable than that of Salmonella species, and protein identification revealed that HBB components were expressed only from one of the two sets of flagellar gene clusters on the R. sphaeroides genome, under the heterotrophic growth conditions tested here.

Treatment of acute promyelocytic leukemia: strategy toward further increase of cure rate

Acute promyelocytic leukemia (APL) has become a curable disease by all-trans retinoic acid (ATRA)-based induction therapy followed by two or three courses of consolidation chemotherapy. Currently around 90% of newly diagnosed patients with APL achieve complete remission (CR) and over 70% of patients are curable. To further increase the CR and cure rates, detection and diagnosis of this disease at its early stage is very important, hopefully before the appearance of APL-associated coagulopathy. In induction therapy, concomitant chemotherapy is indispensable, except for patients with low initial leukocyte counts. Prophylactic use of intrathecal methotrexate and cytarabine should be done, particularly for patients with hyperleukocytosis. If patients relapse hematologically or even molecularly, arsenic trioxide will be the treatment of choice under careful electrocardiogram monitoring. Am80, liposomal ATRA, gemtuzumab ozogamicin or ATRA in combination with cytotoxic drugs may be used at this stage or later. Allogeneic SCT will be the treatment of choice after patients of age <50 years have relapsed, provided that they have HLA-identical family donors or DNA-identical unrelated donors.

Studies on the ATP3 gene of Saccharomyces cerevisiae: presence of two closely linked copies, ATP3a and ATP3b, on the right arm of chromosome II

In this paper, we present evidence that there are two closely linked copies of the ATP3 gene coding for the gamma subunit of the F(1)F(0)-ATPase complex (EC3.6.1.34) in four laboratory strains of Saccharomyces cerevisiae, even though the yeast genome project has reported that ATP3 is a single-copy gene on chromosome II. We previously reported that the gene dosage (three copies) of ATP1 and ATP2 is coincident with the subunit number of F(1)-alpha and F(1)-beta, but that the gene dosage of ATP3 was not consistent with the subunit stoichiometry of F(1)F(0)-ATPase. By applying long PCR and gene walking analyses, we estimated that the two copies of ATP3 were approximately 20 kb apart, and we designated that which is proximal to the centromere ATP3a, while we named that which is distal ATP3b. The nucleotide sequences of the two copies of ATP3 were identical to the reported sequence in the W303-1A, W303-1B and LL20 strains, while only the DC5 strain had a single base substitution in its ATP3a. With the exception of this substitution, the other nucleotide sequences were identical to the upstream 860 bp and the downstream 150 bp. The differences between ATP3 with the single base substitution (Ser(308) to Phe) and ATP3 without the substitution on the complementation of the ATP3 disruptant and on the maintenance of the mitochondrial DNA were observed, suggesting that Atp3ap and Atp3bp in the DC5 strain might have different functions. However, it should not always be necessary for yeast cells to carry different types of ATP3 because the other three strains carry the same type of ATP3. It was also demonstrated that the disruption of the ATP3 genes basically leads to a loss of wild-type mtDNA, but the stability of the mtDNA is not dependent on the ATP3 alone.

Deterioration in learning and memory of inferential tasks for evaluation of transitivity and symmetry in aged SAMP8 mice

This study examined age-dependent deficits in the learning and memory of inferential tasks, using an established senescence-accelerated mouse model in age-related brain dysfunction (SAMP8) and its genetically related inbred strain (SAMR1). The mice learned two sets of nonspatial odor-odor pairs by association learning successively (i.e., A-->B, X-->Y, then B-->C, Y-->Z). They were tested in transitive inference (i.e., A-->C, X-->Z) and symmetrical inference (i.e., C-->B, Z-->Y). In the probe test of A-->C, X-->Z transitive inference, 1-month-old SAMP8 and control SAMR1 at the same age significantly chose the alternative based on transitive inference, but 4- and 7-month-old SAMP8 performed at a random chance level, in comparison with unambiguous inference by control SAMR1 at the same ages. During the test of C-->B, Z-->Y symmetrical inference, SAMP8 at 1 month of age made errors as frequently as control SAMR1 at the same age, but SAMP8 at 4 and 7 months of age made more errors than SAMR1 at the same ages. At 4 and 7 months of age, SAMP8 made more errors than 1-month-old SAMP8. Control SAMR1 did not show such an age-related deficient. These results indicate that SAMP8 mice have age-related learning and memory deficits in the ability to perform inferential tasks. Age-related hippocampal dysfunction is suggested to be the cause of these age-related deficits in old SAMP8 mice during the performance of inferential tasks mediated by declarative memory.

p53-dependent hyperthermic enhancement of tumour growth inhibition by X-ray or carbon-ion beam irradiation

To elucidate p53-dependency on combined treatment with radiation and hyperthermia, growth inhibition and apoptosis were analysed using transplantable human tumour. Human head and neck squamous cell carcinoma (HNSCC) cells carrying different p53 genes were transplanted into the thigh of nude mice. When the mean diameter of tumour reached 5-6 mm, the tumours were exposed to X-rays (2 Gy) or Carbon-ion (C-) beams (1 Gy) followed by heating at 42 degrees C for 20 min. Tumour growth inhibition was evaluated by measuring the diameters of tumour. The induction of apoptosis and accumulation of apoptosis-related proteins were also analysed by immunohistochemical staining. Synergistic enhancement of tumour growth inhibition by hyperthermia was observed in wild-type p53 tumours treated with X-rays or C-beams but not in mutant p53 tumours. The incidence of apoptotic cells and activated-caspase-3-positive cells after combined treatment with them were significantly high in wild-type p53 tumours compared with that in mutant p53 tumours. The hyperthermic enhancement of tumour growth inhibition by X-ray- or C-beam-irradiation was p53-dependent, suggesting that it might be highly correlated with p53-dependent apoptosis.