Full-gap superconductivity in spin-polarised surface states of topological semimetal β-PdBi2

A bulk superconductor possessing a topological surface state at the Fermi level is a promising system to realise long-sought topological superconductivity. Although several candidate materials have been proposed, experimental demonstrations concurrently exploring spin textures and superconductivity at the surface have remained elusive. Here we perform spectroscopic-imaging scanning tunnelling microscopy on the centrosymmetric superconductor β-PdBi2 that hosts a topological surface state. By combining first-principles electronic-structure calculations and quasiparticle interference experiments, we determine the spin textures at the surface, and show not only the topological surface state but also all other surface bands exhibit spin polarisations parallel to the surface. We find that the superconducting gap fully opens in all the spin-polarised surface states. This behaviour is consistent with a possible spin-triplet order parameter expected for such in-plane spin textures, but the observed superconducting gap amplitude is comparable to that of the bulk, suggesting that the spin-singlet component is predominant in β-PdBi2.Although several materials have been proposed as topological superconductors, spin textures and superconductivity at the surface remain elusive. Here, Iwaya et al. determine the spin textures at the surface of a superconductor β-PdBi2 and find the superconducting gap opening in all spin-polarised surface states.

High-temperature-required protein A2 as a predictive marker for response to chemotherapy and prognosis in patients with high-grade serous ovarian cancers

Background:

High-temperature-required protein A2 (HtrA2), a protein relating with apoptosis in a caspases-dependent and non-dependent manner, has been reported to be associated with chemosensitivity in several human cancers.

Methods:

Tissue microarrays made from 142 patients with high-grade serous ovarian adenocarcinoma were evaluated to assess whether HtrA2 expression was related with several clinical parameters.

Results:

Negative HtrA2 expression was observed in 36 cases (25%) of the patients, and related with significantly lower response rates of primary chemotherapy than those with positive HtrA2 expression (56% vs 83%, P<0.01). In addition, negative HtrA2 expression was identified as an independent worse prognostic factor for progression-free survival and overall survival by multivariate analyses. Furthermore, HtrA2 downregulation modulated sensitivity to platinum in serous ovarian cancer cells in vitro.

Conclusions:

HtrA2 expression was a predictor for sensitivity to chemotherapy, and could be a candidate of molecular target in the treatment of high-grade serous ovarian cancers.

Impact of lithium-ion ordering on surface electronic states of Li(x)CoO2

Li(x)CoO(2) exhibits intriguing electronic properties due to a strong electron correlation and complex interplay between Co and Li ions. However, fundamental understanding of the nanoscale distribution of Li ions and its effect on the electronic properties remains unclear. We use scanning tunneling microscopy and density functional theory to elucidate the degree of Li(x)CoO(2) surface electronic state modification that can be achieved by Li ordering. The surface Li ions are highly mobile and preferentially form a (1 × 1) hexagonal lattice, whereas the surface CoO(2) layer shows metallic and insulating phases, indicating the coexistence of ordered and disordered Li ions in the subsurface layer. These results provide evidence of novel electronic properties produced by spatially inhomogeneous Li-ordering patterns.

Fibrinogen γ-chain peptide-coated, ADP-encapsulated liposomes rescue thrombocytopenic rabbits from non-compressible liver hemorrhage

BACKGROUND

We developed a fibrinogen γ-chain (dodecapeptide HHLGGAKQAGDV [H12])-coated, ADP-encapsulated liposome (H12-[ADP]-liposome) that accumulates at bleeding sites via interaction with activated platelets via glycoprotein IIb-IIIa and augments platelet aggregation by releasing ADP.

OBJECTIVE

To evaluate the efficacy of H12-(ADP)-liposomes for treating liver hemorrhage in rabbits with acute thrombocytopenia.

METHODS

Thrombocytopenia (platelets < 50 000 μL(-1)) was induced in rabbits by repeated blood withdrawal (100 mL kg(-1) in total) and isovolemic transfusion of autologous washed red blood cells. H12-(ADP)-liposomes with platelet-poor plasma (PPP), platelet-rich plasma (PRP), PPP, ADP liposomes with PPP or H12-(PBS)-liposomes/PPP, were administered to the thrombocytopenic rabbits, and liver hemorrhage was induced by penetrating liver injury.

RESULTS

Administration of H12-(ADP)-liposomes and of PRP rescued all thrombocytopenic rabbits from liver hemorrhage as a result of potent hemostasis at the liver bleeding site, although rabbits receiving PPP or ADP liposomes showed 20% survival in the first 24 h. Administration of H12-(ADP)-liposomes and of PRP suppressed both bleeding volume and time from the site of liver injury. H12-(phosphate-buffered saline)-liposomes lacking ADP also improved rabbit survival after liver hemorrhage, although their hemostatic effect was weaker. In rabbits with severe thrombocytopenia (25 000 platelets μL(-1)), the hemostatic effects of H12-(ADP)-liposomes tended to be attenuated as compared with those of PRP treatment. Histologic examination revealed that H12-(ADP)-liposomes accumulated at the bleeding site in the liver. Notably, neither macrothombi nor microthrombi were detected in the lung, kidney or liver in rabbits treated with H12-(ADP)-liposomes.

CONCLUSIONS

H12-(ADP)-liposomes appear to be a safe and effective therapeutic tool for acute thrombocytopenic trauma patients with massive bleeding.

Abstract P1-13-09: Marked Inhibition of Both Invasion and Proliferation by Zoledronic Acid and the Epidermal Growth Factor Receptor Inhibitor Gefitinib in a Bone-Seeking Clone of Breast Cancer

Background: Zoledronic acid (Zol) is the most potent inhibitor of bone resorption in bisphosphonates. In order to examine whether the inhibitory effect is involved in the mechanism of bone metastasis in breast cancer, a bone-seeking clone was examined. It was established by repeated sequential passages of metastatic cells from bone in nude mice and in vitro, and it exclusively metastasizes to bone with larger osteolytic lesions than MDA-MB-231 parental cells. Recent findings indicate that epidermal growth factor (EGF) signaling is also an important mediator of bone metastasis. We examined the synergistic effects of gefitinib on the proliferation and invasion of a bone-seeking clone compared with MDA-MB-231. Materials and Methods: The cellular proliferation was estimated using WST-1. Migration in the matrigel in a Boyden chamber was applied to the invasion assay.

Results: Treatment with 1 µM of Zol reduced 51% of cell proliferation in the bone-seeking clone; however, the inhibited rate was 37% in MDA-MB-231. The migration was also inhibited with 10 µM of Zol (bone-seeking clone: 69% reduction, MDA-MB-231: 54% reduction). The reduction rates of both assays by Zol treatment were significantly higher in the bone-seeking clone than in MDA-MB-231. Treatment with 10 µM of Zol plus 1 µM of gefitinib resulted in a proliferation reduction rate of 27% compared to that with 10 µM Zol treatment in the bone-seeking clone and no reduction in MDA-MB-231.

The migration reduction rate was 88% in the bone-seeking clone and no reduction in MDA-MB-231.

There was a significant difference between the bone-seeking clone and MDA-MB-231 in the reduction rates of both cellular proliferation and migration. Although the effect of gefitinib was synergistic with that of Zol in the bone-seeking clone, it was not clear in MDA-MB-231.

Conclusion: There appear to be at least two independent signaling pathways that occur in osteolytic bone metastasis. One is involved in the bone resorption of bisphosphonates, and the other is an EGFR signaling pathway. Clinically, the combination of Zol and gefitinib is suggested to be a strong therapy specific to bone metastasis.

EGF-dependent enhancement of invasive ability in squamous cell carcinoma of the breast

Abstract #2061

The factors promoting the clinical aggressiveness of squamous cell carcinoma of the breast is still not well understood. In order to examine whether the mechanism of cell motility is involved in the aggressive behavior of squamous cell carcinoma, we established a squamous cell carcinoma cell line from breast primary (HBC 9) and assayed its invasiveness. The number of HBC9 cells migrating through matrigel was significantly increased by stimulation with epidermal growth factor (EGF). This enhancement of cell motility was distinctly detected in comparison with four ductal carcinoma cell lines (MCF7, BT474, HBC5, and MDA-MB-231). EGF stimulation also induced surface protrusions of HBC9 cells. To examine the interaction between Arp2/3 complex and N-WASP which is the final intracellular signal of invadopodia formation that is downstream from EGF stimulation, we observed surface protrusion of HBC 9 by laser microscopy. Co-localization of Arp2 and N-WASP was detected with actin polymerization visualized by phalloidin. Furthermore, the localization of cortactin was found to agree with that of N-WASP and Arp2/3 complex in the invadopodia. The cortactin gene copy number was evaluated using real time PCR by comparison between 12 DNA samples extracted from primary mammary squamous cell cancer tissue and those from corresponding normal breast tissue. A higher level of cortactin was detected in cancer tissue than in normal tissue in 10 cases (83%). At a protein level, intense immunostaining of cortactin was detected in all 12 cases, among which expression was confirmed in 2 cases by Western blot analysis. These results suggest that one of the causes of clinical aggressiveness of squamous cell carcinoma of the breast is the enhancement of cell motility by invadopodial formation. Overexpression of cortactin may result in the formation of invadopodium.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2061.

Local tunneling spectroscopy across a metamagnetic critical point in the bilayer ruthenate Sr3Ru2O7

The local spectroscopic signatures of metamagnetic criticality in Sr(3)Ru(2)O(7) were explored using scanning tunneling microscopy (STM). Singular features in the tunneling spectrum were found close to the Fermi level, as would be expected in a Stoner picture of itinerant electron metamagnetism. These features showed a pronounced magnetic field dependence across the metamagnetic critical point, which cannot be understood in terms of a naive Stoner theory. In addition, a pseudogap structure was observed over several tens of meV, accompanied by a c(2 x 2) superstructure in STM images. This result represents a new electronic ordering at the surface in the absence of any measurable surface reconstruction.

Imaging nanoscale electronic inhomogeneity in the lightly doped Mott insulator Ca(2-x)NaxCuO2Cl2

The spatial variation of electronic states was imaged in the lightly doped Mott insulator Ca(2-x)NaxCuO2Cl2 using scanning tunneling microscopy or spectroscopy. We observed nanoscale domains with a high local density of states within an insulating background. The observed domains have a characteristic length scale of 2 nm (approximately 4-5a, a: lattice constant) with preferred orientations along the tetragonal [100] direction. We argue that such spatially inhomogeneous electronic states are inherent to slightly doped Mott insulators and play an important role for the insulator to metal transition.

Dioxin suppresses the checkpoint protein, MAD2, by an aryl hydrocarbon receptor-independent pathway

The compound 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been shown recently to be carcinogenic, but little is currently known about the molecular mechanism of TCDD affecting cell proliferation and carcinogenesis. In this report, we demonstrate that TCDD suppresses the expression of the checkpoint protein, Mad2. Suppression of Mad2 was also observed in aryl hydrocarbon receptor-deficient mouse embryonic fibroblasts, suggesting that TCDD suppresses Mad2 by a novel TCDD receptor signaling mechanism. In addition, HeLa cells treated with TCDD failed to arrest in mitosis after nocodazole treatment. The Mad2 protein plays a significant role in accurate chromosome segregation in mitotic cells. Our data suggest that TCDD may increase chromosomal instability through the suppression of Mad2 expression.

Determination of enantiomeric purity of hyoscyamine from scopolia extract using HPLC-CD system without chiral separation

Enantiomeric ratio of hyoscyamine from Scopolia extract was determined by chiral HPLC-CD analysis. It was found that circular dichroism (CD) detection allowed the analysis of the sample without any special pretreatment whereas UV detection required an ammonia-ether extraction. To obtain a shorter analysis time for the determination, reversed-phase HPLC-CD analysis was applied by using a g-factor calibration curve (EE% vs. CD/UV). The analysis time was shortened from 35 to 18 min. EE% values obtained were consistent with those by chiral HPLC analysis.

Nuclear accumulation of beta-catenin in intestinal-type gastric carcinoma: correlation with early tumor invasion

Mutation of the adenomatous polyposis coli gene, which is known to be an early event in the carcinogenesis of intestinal-type gastric carcinoma, leads to accumulation of beta-catenin. In addition, beta-catenin has been found to activate down stream signaling molecules in the wingless/Wnt pathway. In this study, the clinical significance of nuclear accumulation of beta-catenin was evaluated in gastric carcinoma. Immunohistochemical staining showed nuclear localization in 16 (12%) of 139 (94 intestinal-type and 45 diffuse-type) gastric carcinomas, and all 16 lesions with nuclear staining were intestinal-type adenocarcinomas. Of the 16 cases, 15 were in the early clinical stage. In the remaining case, the lesion had invaded the subserosal layer and showed strong nuclear staining at the invasive front. In 14 of the 16 cases with nuclear localization, there were no abnormal mobility shifts detected using polymerase chain reaction-single strand conformational polymorphism analysis. This was confirmed using direct sequencing analysis, which revealed the wild-type sequence in the 12 cases tested. Nuclear accumulation of beta-catenin did not correlate with lymph node metastasis or 5-year survival. These findings suggest that high intranuclear levels of beta-catenin protein play an important role in early tumor growth and may function in initiation of invasive processes in intestinal-type gastric carcinoma.

Direct observation of the washboard noise of a driven vortex lattice in a high-temperature superconductor, Bi2Sr2CaCu2O(y)

We studied the conduction noise spectrum in the vortex state of a high-temperature superconductor, Bi(2)Sr(2)CaCu(2)O(y), subject to a uniform driving force. Two characteristic features, a broad-band noise (BBN) and a narrow-band noise (NBN), were observed in the vortex-solid phase. The origin of the large BBN was determined to be plastic motion of the vortices, whereas the NBN was found to originate from the washboard modulation of the translational velocity of the driven vortices. We believe this to be the first observation of washboard noise of dc driven vortices in any superconductor.

A case of cytophagic histiocytic panniculitis associated with exertional rhabdomyolysis

An 18-year-old man who suffered from panniculitis involving the entire left lower limb after exertional rhabdomyolysis is reported. A high fever (>39 degrees C) and leukocytosis (>20,000/microL) persisted for 1 week, and his general status deteriorated rapidly into pre-disseminated intravascular coagulation, complicated by pleural effusion and prolonged clotting time. His condition was dramatically improved by steroid pulse therapy and he has remained in good health for the 20 months since discharge. Histologic examination of subcutaneous tissue from the swollen left lower limb revealed pleomorphic small, medium or large lymphocytes, macrophages and neutrophils infiltrating the edematous subcutaneous adipose tissue in a lobular panniculitis-like pattern. The majority of inflammatory cells were T lymphocytes, with equal proportions of CD4+ and CD8+ cells. As polymerase chain reaction did not show bands suggesting T cell receptor gamma gene rearrangement, the proliferation of T lymphocytes was considered to be polyclonal. The T lymphocytes also expressed Fas ligand, suggesting the involvement of Fas-mediated cytotoxicity. This case may represent a new category of cytophagic histiocytic panniculitis induced by exertional rhabdomyolysis.

Neurotrophic agents in fibrin glue mediate adult dorsal root regeneration into spinal cord

OBJECTIVE

The aim of the present study was to determine whether neurotrophic factors (NTFs) exogenously administered in fibrin glue assisted cut dorsal root axons of adult rats to regenerate into the spinal cord.

METHODS

Rats received intraspinal implants of fibrin glue containing neurotrophin-3, brain-derived NTF, ciliary NTF, or Dulbecco's modified Eagle's medium (control) into left dorsal quadrant cavities aspirated in the lumbar enlargement. The transected L5 dorsal root stump was placed at the bottom of the lesion cavity and was secured between the fibrin glue and the spinal cord. Regenerated dorsal root axons were subsequently labeled with immunohistochemical methods to demonstrate those that contained calcitonin gene-related peptide.

RESULTS

Calcitonin gene-related peptide-immunoreactive dorsal root axons regenerated across the dorsal root-spinal cord interface of rats with fibrin glue containing neurotrophin-3, brain-derived NTF, or ciliary NTF, entered the spinal cord, and frequently arborized within clusters of motoneuronal cell bodies. Only a few axons regenerated into the spinal cord of animals with fibrin glue implants that lacked NTF, and their growth within the spinal cord was extremely limited. The results of quantitative studies confirmed these observations.

CONCLUSION

Our results indicate that neurotrophin-3, brain-derived NTF, and ciliary NTF enhance dorsal root regeneration into spinal cord and that fibrin glue is an effective medium for intraspinal delivery of NTF. This method of delivering NTF may therefore provide a strategy for restoring injured spinal reflex arcs.

Increased ubiquitin immunoreactivity in hepatocellular carcinomas and precancerous lesions of the liver

BACKGROUND/AIMS

Ubiquitin covalently attaches to abnormal and short-lived proteins, thus marking them for ATP-dependent proteolysis in eukaryotic cells. Increased ubiquitin immunoreactivity was recently observed immunohistochemically in human malignant tumors. To clarify the change in protein metabolism during hepatocarcinogenesis, we studied ubiquitin immunoreactivity in hepatocellular carcinomas (HCCs) and precancerous lesions using immunohistochemistry and immunoblot analysis.

METHODS

A total of 72 HCCs (37 advanced, 19 early, 16 early-advanced (advanced HCC component in early HCC nodule) type HCCs) and 18 precancerous lesions (8 atypical adenomatous hyperplasias (AAHs), 10 adenomatous hyperplasias (AHs)) were studied immunohistochemically. Immunoblot analysis was also performed in advanced HCC and early HCC cases.

RESULTS

Non-tumorous hepatocytes were either immunonegative or weakly stained in their nuclei. Advanced HCCs showed strong immunoreactivity in most cases, while early HCCs showed relatively weaker immunoreactivity. In 14 of 16 early-advanced type tumors, the inner portion of the nodules, which corresponds to advanced HCC, showed stronger immunoreactivity than the outer low-grade portion. In 8 of 8 AAHs and 7 of 10 AHs, positive but weak staining was found. Immunoblot analysis showed an increase in 42 kDa ubiquitinated protein(s) in 8 of 16 advanced HCC cases (50%) and in 1 of 6 early HCC cases (16.7%), as well as an increase in several other bands in tumor tissues.

CONCLUSIONS

The intensity of ubiquitin staining appeared to increase in a stepwise manner from AH to advanced HCC, and the results suggest a possible correlation between changes in the ubiquitinated proteins and multistep hepatocarcinogenesis.

Immunoreaction at 43 kDa with anti-ubiquitin antibody in breast neoplasms

Protein ubiquitination has been implicated in ATP-dependent protein turnover and normal cell proliferation. To investigate whether the ubiquitin-mediated system is functionally involved in the cancerous state, we examined changes in protein ubiquitination in 52 surgically resected primary breast tumors. Immunohistochemically, ubiquitin (Ub) was identified in the cytoplasm of cancer cells, which were stained more strongly than adjacent normal ductal epithelium. Corresponding immunoblot analysis of normal and neoplastic regions of human breast showed that the immunoreaction for Ub at about 43 kDa was increased in all of the tumors (100%), regardless of the clinical stage or histologic grade. This protein, which gave a single spot on two-dimensional gel electrophoresis, had partial amino acid sequences which were identical to those of actin family members. Our results suggest that ubiquitination of this 43-kDa protein may be involved in the carcinogenesis or biological characteristics of human breast neoplasms.

Histologic grade and p53 immunoreaction as indicators of early recurrence of node-negative breast cancer

Even among breast cancer patients without metastasis to axillary lymph nodes, early recurrence can occur. To determine the risk factors for early recurrence, we performed a case-control study between 32 patients with an early recurrence of breast cancer and 122 patients without recurrence, in which tumor size, age of patient and date of operation were matched. In all 154 node-negative patients, followed up over a 13.1-year median period, expression of p53, c-erbB-2 and cathepsin D in the primary tumor were studied immunohistochemically in paraffin-embedded tissues and were compared with morphologic factors such as histologic grade and invasive growth. Univariate analysis showed that nuclear p53 immunoreaction was significantly predictive of early recurrence [risk ratio (RR) 3.3]. Likewise, cathepsin D (RR 0.22) was significantly negatively associated; however, when the risk ratio was analyzed in terms of intensity of cathepsin D staining, no superior survival was found for patients with strongly positive tumors. Overexpression of c-erbB-2 protein was not associated with outcome by either univariate or multivariate analysis. As a whole, histologic grade was confirmed as being a strong predictor (RR 42.6) and multivariate analysis showed that only histologic grade was a significant risk factor for early recurrence. p53 immunoreaction was not a significant independent factor because it was closely linked to histologic grade (P = 0.002), especially to a high mitotic index (P < 0.001). Moreover, in 14 patients with "special histologic types' of invasive carcinomas and no recurrence, all were p53-negative except one medullary carcinoma. Nuclear p53 immunoreaction is useful in supporting histologic grade to detect a high-risk for early recurrence in node-negative patients who may be eligible for systemic adjuvant therapy.

[Positron emission tomographic evaluation for frontal hypertrophic cranial pachymeningitis using 11C-methyl-L-methionine]

A case of frontal hypertrophic cranial pachymeningitis was presented with positron emission tomography (PET) using (11C-methyl)-L-methionine (11C-Met). A 55-year-old male developed right hemiparesis after generalized tonic convulsion one month prior to admission. MR images revealed patchy enhancement extending from the dura mater to the cerebral parenchyma surrounding high T2-weighted signal in the left frontal region. Left carotid angiogram showed atresia of the rostral superior sagittal sinus and obliteration of the cortical veins associated with compensatory venous channels coursing in the frontal deep white matter. PET demonstrated high 11C-Met uptake in the area corresponding to the enhancing lesion on the MR images. The ratio of lesion/normal cortex was 1.58 as an indicator of selective uptake in the lesion. The contralateral temporal gray matter was representative of a normal cortex. In contrast, 11C-Met did not accumulate in the frontal white matter where T2-weighted MR images showed abnormal high intensity lesion. This suggested that the frontal white matter lesion was derived from vasogenic edema due to venous infarction. The patient underwent an uneventful exploratory biopsy. The dura mater had proliferated to a thickness of 3.5mm and was tightly adherent to the left middle frontal gyrus. Microscopically, the thickened dura mater where the tracers had accumulated was composed of abundant collagenous fibers together with diffuse infiltration of inflammatory cells, including predominantly lymphocytes, plasma cells, and neutrocytes. The lymphocytes, which proved positive in both UCHL-1 and L26 staining, had no atypism. Histological findings corresponded to hypertrophic pachymeningitis. Met-PET clearly represented viable and infiltrative zones of inflammatory cells. The patient's neurological symptoms and signs gradually improved. Follow-up MR images three months after the surgery showed the enhancing lesion to be diminished and a marked regression of the vasogenic edema. Spatial determination of viable lesions permitting differentiation from biological inactive or vasogenic edema is an important guideline in selecting an appropriate surgical procedure in the diagnosis and treatment of hypertrophic cranial pachymeningitis. Met-PET would appear useful in delineating inflammatory lesions such as hypertrophic cranial pachymeningitis.

Natural state of mutant p53 protein and heat shock protein 70 in breast cancer tissues

BACKGROUND

Nuclear accumulation of p53 protein in breast cancer cells is generally accepted as a marker for the presence of p53 gene mutation and as an indicator of poor prognosis. Mutation in the p53 gene has been shown to cause conformational change in the p53 protein, which gives rise to a complex with heat shock protein 70 (hsp70).

EXPERIMENTAL DESIGN

To clarify whether the p53 protein that accumulates in the nuclei of human cancer cells is bound to hsp70 in vivo, we compared the immunohistochemical localization of both p53 and hsp70 in 65 surgically resected cases of primary breast cancer. In four cases showing both nuclear accumulation of p53 protein and mutation of the p53 gene, identified by single-strand conformation polymorphism and direct sequence analysis, the presence of the p53-hsp70 complex was examined by coimmunoprecipitation assay. In 12 human cancer cell lines showing nuclear accumulation of the p53 protein, the presence of the p53-hsp70 complex was also examined by immunoprecipitation with two anti-p53 Ab after labeling with [35S]methionine.

RESULTS

Among the 65 cases, p53 and hsp70 immunoreaction in cancer cell nuclei was detected immunohistochemically in 16 (25%) and 23 (35%) cases, respectively. The localizations of the two proteins were significantly correlated, but there was a discrepancy in the localization patterns in 23 cases. Although the p53-hsp70 complex was detected in all of the four cases in which the p53 mutation was identified, the expression levels of hsp70 detected by coimmunoprecipitation assay were much weaker than those of p53 protein. In all of the 12 cancer cell lines with nuclear accumulation of p53, no distinct 70-kDa bands were immunoprecipitated with the p53 protein.

CONCLUSIONS

In human breast cancer tissue, only part of the pool of p53 is bound to hsp70.

Monoamine release in the rat striatum is induced by delta-guanidinovaleric acid and inhibited by GABA agonists

delta-Guanidinovaleric acid (GVA) is an endogenous convulsant and is thought to be a specific gamma-aminobutyric acid (GABA) antagonist. In this study, we examined the effects of GVA and GABA agonists, GABA, muscimol and baclofen, on the release of dopamine (DA) and serotonin (5-HT) in the rat striatum using a brain dialysis technique. GVA produced a significant increase in the amount of DA and 5-HT released compared with controls. Both GABA (10mM) and muscimol (10mM) inhibited the GVA-induced release of DA and 5-HT. Muscimol was a more potent inhibitor of 5-HT release than DA release. Baclofen (10mM) inhibited only the GVA-induced DA release. These results suggest that the activation of GABA receptors inhibits the release of DA and 5-HT in the striatum, and that the dopaminergic system regulates GABA-B receptors and the serotonergic system mainly regulates GABA-A receptors.

p53 mutations and c-erbB-2 amplification in intraductal and invasive breast carcinomas of high histologic grade

In order to clarify the clinical significance of mutations of the p53 gene and amplification of the c-erbB-2 gene in breast carcinoma, these gene alterations were examined in 101 invasive, seven predominantly intraductal and 10 intraductal breast carcinomas by single-strand conformation polymorphism-direct sequencing or Southern blot-hybridization analysis. p53 mutations were detected in 32 (32%) of the invasive cases and two (12%) of the 17 intraductal/predominantly intraductal cases, whereas c-erbB-2 amplification was detected in 14 (14%) of the invasive and six (35%) of the intraductal/predominantly intraductal cases. Irrespective of differences in the positions and types of the mutations, cases carrying p53 mutations were almost always Grade 3 histologically and with a low hormone-receptor value. Since p53 mutations as well as c-erbB-2 amplification were detected almost selectively in Grade 3 cases but were not associated with lymph nodal status in invasive breast cancer, these two gene alterations could be indicators of prognosis of disease independent of lymph nodal status. Even in intraductal/predominantly intraductal carcinoma, these gene alterations were almost always detected in tumors of higher histologic grade. Thus, it is suggested that these gene alterations occur in breast cancers showing a high proliferation rate irrespective of the presence of invasion, and that other molecular alterations are involved in the process of breast cancer invasion.

Nuclear p53 immunoreaction associated with poor prognosis of breast cancer

p53 protein has been frequently detected at high levels in the nuclei of human breast cancer cells. We analyzed immunohistochemically the association between nuclear localization of p53 protein and clinical and histological parameters of breast cancer patients. Surgically resected tissues of 73 primary breast cancers were processed by acetone fixation and paraffin embedding and examined using an anti-p53 monoclonal antibody, PAb1801. p53 immunoreactivity was detected in the nuclei of cancer cells in 17 cases (23%). The nuclear p53 immunoreaction was closely associated with overexpression of c-erbB-2 protein (P less than 0.05), high histologic grade (P less than 0.01), advanced clinical stage (P less than 0.05), and negative estrogen receptor status (P less than 0.01). When 31 cases which had been followed up for more than 50 months were examined, a positive nuclear p53 immunoreaction was found to be significantly associated with shorter overall survival of patients (P less than 0.01). These results suggest that immunohistochemical examination of nuclear p53 protein is clinically useful as an indicator of breast cancer aggressiveness.

Detection of platelet consumption in aortic graft with 111In-labeled platelets

Increased platelet consumption in two patients with aortic graft was detected by scintiphotography using 111In-labeled autologous platelets. There was shortened platelet survival time in these patients. These findings might suggest that platelet consumption in aortic prosthesis is related to thrombogenesis.