A consistent region of deletion on 1p36 in meningiomas: identification and relation to malignant progression

We analyzed the genetic aberrations on chromosome arms 1p, 10q, and 14q, which are thought to be loci that include putative tumor suppressor genes in meningiomas. We initially conducted molecular genetic testing on a total of 72 tumors including 15 atypical and 8 anaplastic meningiomas using double-target fluorescence in situ hybridization. An incidence of deletion of 1p was observed in 16.3% of histologically benign, 86.7% of atypical, and 87.5% of anaplastic meningiomas. Microsatellite analysis for loss of heterozygosity on 1p, 10q, and 14q was performed in 15 tumors (6 benign, 6 atypical, and 3 anaplastic meningiomas). We detected a limited deleted region on 1p36 in two tumors and suggest a new consistent region of deletion at 1p36.21p23 distal to D1S507 and proximal to D1S214, which spans 8.21 megabases. In addition, loss of 10q was detected in two of three secondary atypical meningiomas, and loss of 14q in two of three primary anaplastic meningiomas. We suggest that one of the putative suppressor genes is located at 1p36.21p23, and that 10q loss may contribute to the malignant progression from benign to atypical meningiomas.     

Tubular aggregates in the skeletal muscle of the senescence-accelerated mouse; SAM

We investigated the skeletal muscles of nine strains of senescence accelerated mouse (SAM), DDD, AKR/J, C57BL/6J, A/J and BALB/c mice. We found that male SAMP8, SAMP7, C57BL/6J, A/J and BALB/c mice expressed tubular aggregates (TAs) in their skeletal muscle. Among these strains, the SAMP8 strain, which exhibits a short life span and various age-associated neurodegenerative disorders plus mitochondrial dysfunction, showed TAs more markedly than the others. Thus, we compared SAMP8 mice against SAMR1 mice, an accelerated senescence-resistant strain. Light- and electron micrographs showed that male SAMP8 mice exhibited an age-dependent aggravation of TA accumulation. There were no significant differences in the serum lactate/pyruvate levels between the SAMP8 and SAMR1 mice. However, the serum creatine kinase (CK) levels of the 3 and 6-month-old SAMP8 mice were higher than that of the corresponding SAMR1 mice. Considering the serum CK levels and the mitochondrial dysfunction of SAMP8 mice, we conclude that the TAs may be involved in the homeostasis of energy metabolism that is not appropriately regulated in the SAMP8 mouse mitochondrion.     

Grading score system: A method for evaluation of the degree of senescence in Senescence Accelerated Mouse (SAM)

For evaluation of the degree of senescence in SAM-P, accelerated senescence prone mouse, formerly called SAM or prone series or P-series, consisting of SAM-P/1, SAM-P/2, SAM-P/3 and SAM-P/4 corresponding to P-1, P-2, P-3 and P-4 series, respectively, in the previous reports, and in SAM-R, accelerated senescence resistant mouse, formerly called resistant series or R-series, consisting of SAM-R/1, SAM-R/2 and SAM-R/3 corresponding to R-1, R-2 and R-3 series, respectively, in the previous reports, the grading score system was adopted. The items to be examined in this system include 11 categories selected from the clinical signs and gross lesions considered to be associated with the aging process. The degree of the senescence in each category was graded from 0 to 4 according to the detailed criteria devised in our laboratory. After 8 months of age each mouse was examined every 4 months, and some of the mice were examined after 2 months of age.In almost all categories, the grading score and incidence began to increase from 4 or 6 months of age and continued to increase with advancing age in both SAM-P and SAM-R. The increase, however, was more marked in SAM-P than in SAM-R. The slow but steady increase in the SAM-R levelled out at 24 months of age and was comparable to that of 12 months of age in SAM-P. In both SAM-P/1 at 8 months of age and SAM-R/2 at 12 months of age, there was a significant reverse correlation between total score of this grading score system and length of residual life after examination.Systematic and extensive studies using the grading score system showed that if the validity of the system is, based on “irreversibility” and “universality” of the changes in     

Studies on B-cell memory. II. T-cell independent antigen can induce B-cell memory.

Both athymic nude mice and normal mice primed with a T-cell independent antigen, i.e. dinitrophenylated dextran (DNP-DE), at a sub-immunogenic dose, produced very poor anti-DNP responses to a later challenge with the same antigen. B-cell memory was expressed, however, as an enhanced IgM response after the challenge of the DNP-DE-primed mice with the T-cell dependent antigen (dinitrophenylated haemocyanin, DNP-KLH) in the presence of functional T-cells. Moreover, DNP-DE-primed spleen cells also revealed an enhanced IgM response after adoptive transfer into irradiated recipients and challenge with DNP-DE. The injections of DNP-DE-primed nude mouse serum into unprimed mice resulted in the reduction of anti-DNP response to the immunization with DNP-DE. These results indicate that (a) T-cell independent DNP-DE causes the differentiation of B cells not only into antibody-forming cells but also into memory cells, (b) these memory cells can be triggered in situ by the T-cell dependent DNP-KLH in the presence of helper T cells but not by T-cell independent antigen, and (c) some humoral factor(s) induced by DNP-DE-priming seems to interfere with the expression of B-cell memory only when challenged with T-cell independent DNP-DE.     

Dominant-negative hypoxia-inducible factor-1 alpha reduces tumorigenicity of pancreatic cancer cells through the suppression of glucose metabolism

In the tumor cells exposed to hypoxia, hypoxia-inducible factor-1 (HIF-1)-mediated adaptation responses such as angiogenesis and anaerobic metabolism are induced for their survival. We have recently reported that the constitutive expression of HIF-1 alpha renders pancreatic cancer cells resistant to apoptosis induced by hypoxia and glucose deprivation. We then established dominant-negative HIF-1 alpha (dnHIF-1 alpha) transfectants and examined their susceptibility to apoptosis and growth inhibition induced by hypoxia and glucose deprivation in vitro and their tumorigenicity in SCID mice. We further examined the expressions of aldolase A and Glut-1 in vitro and Glut-1 expression and glucose uptake in the tumor tissues and microvessel counts in the tumor tissues. As a result, dnHIF-1 alpha rendered the pancreatic cancer cells sensitive to apoptosis and growth inhibition induced by hypoxia and glucose deprivation. Also it abrogated the enhanced expression of Glut-1 and aldolase A mRNAs under hypoxia and reduced the expression of Glut-1 and the glucose uptake in the tumor tissues and consequently in vivo tumorigenicity. We found no significant difference in the microvessel counts among the tumor tissues. From these results, we suggest that the disruption of the HIF-1 pathway might be effective in the treatment of pancreatic cancers.     

Correspondence of cue activity to reward activity in the macaque orbitofrontal cortex

It has been reported that neurons in the orbitofrontal cortex (OFC) respond to emotionally significant events such as reward-predicting cues and/or the reward itself. The responses to reward-predicting cues are considered to carry the information of the predicted reward. However, few studies have focused on the relationship of the neuronal activity during a cue period with that during a reward period. We can infer that the cue responses of OFC neurons are correlated to the reward responses if they carry the information of the predicted reward. In this study, we focused on neurons that showed responses during both the cue and reward periods, and compared the response characteristics between these periods. We found 94 of 369 OFC neurons showed significant responses during both the cue and reward periods, and 43 of which preserved their selectivity between these periods. Furthermore, population analysis showed that stronger cue responses corresponded to stronger reward responses, and stronger reward responses corresponded to stronger cue responses. These results suggest that individual neurons in the OFC associate visual information with reward information, and contribute to the prediction of future rewards by forming reward representations.     

Immune responses in newly developed short-lived SAM mice. IV. Chromosomal location of a gene controlling defective helper T-cell activity.

Short-lived SAMP-P/1 mice are low responders in in vitro antibody responses because of a selectively impaired helper T(Th)-cell activity. After crossing with high responders (B10.BR mice), about 12% of (B10.BR x SAM-P/1) (BRP)F2 mice showed low responsiveness, as did SAM-P/1 mice, against two T-dependent antigens, sheep and horse red blood cells (RBC), both of which were not cross-reactive to each other at helper T- and B-cell levels. The immune activities against the two antigens in individual BRPF2 mice showed a good correlation (r = 0.81), thereby suggesting that SAM-P/1 mice have an antigen non-specific Th cell dysfunction. Based on the incidence of the low responders in F2 generation and statistical analyses, the hypo-responsiveness was postulated to be controlled by two genes. To survey the location of these genes, linkage analyses were performed in the F2 mice using a large set of genetic markers. Low responders in the F2 generation showed a significantly higher incidence of SAM-P/1 genotype at the Gpi-1 as well as c locus on chromosome 7 (Chr.7). However, no linkage of low responsiveness to the Hbb locus was evident, an area present at a more distal site to the centromere on the same chromosome. These results suggest that one of the genes controlling the hypo-responsiveness of SAM-P/1 mice is linked to both Gpi-1 and c loci and that it locates at a more proximal site on Chr.7.     

Establishment of FSH-responsive cell lines by transfection of pre-ovulatory human granulosa cells with mutated p53 (p53val135) and Ha-ras genes.

Human granulosa cells were immortalized by transfection of the primary cells with a mutated p53 gene in combination with the Harvey-ras oncogene, yielding established cell lines designated HGP53. Here we report that forskolin, 8-Br-cAMP and FSH modulate cell growth and steroidogenesis in HGP53 cells. Low concentrations of 8-Br-cAMP or FSH stimulated cell proliferation, while higher doses attenuated cell proliferation. Progesterone production was already evident at an FSH concentration of 0.3 mIU/ml and was maximally stimulated (50-135-fold) at 50 mIU/ml of FSH. Expression levels of steroidogenic acute regulatory protein (StAR), adrenodoxin and cytochrome P450scc were enhanced 64-, 48- and 3.1-fold respectively by FSH stimulation. Dexamethasone enhanced FSH/cAMP-induced steroidogenesis and this effect involved a marked elevation in the intracellular level of adrenodoxin and P450scc, concomitantly with a marked decrease in StAR. Conversely, basic fibroblast growth factor attenuated FSH-stimulated progesterone production, and this effect involved reductions in adrenodoxin, P450scc and StAR levels. These data suggest that the rate of steroidogenesis may be determined by the ratio of StAR and P450scc, rather than by the level of each protein alone. Whereas FSH at a low dose slightly reduced apoptosis induced by serum withdrawal from HGP53 cells, higher doses enhanced it. Dexamethasone dramatically attenuated FSH- or forskolin-enhanced apoptosis. In conclusion, FSH-dependent mechanisms of differentiation, luteinization and apoptosis can be preserved in human granulosa cells immortalized by mutated p53. Moreover, this system lends itself to studies on cross-talk between the endocrine and paracrine factors that control these processes.