SWI by 7T MR Imaging for the Microscopic Imaging Diagnosis of Astrocytic and Oligodendroglial Tumors.

BACKGROUND AND PURPOSE: Despite advances in molecular imaging, preoperative diagnosis of astrocytomas and oligodendrogliomas can be challenging. In the present study, we assessed whether 7T SWI can be used to distinguish astrocytomas and oligodendrogliomas and whether malignant grading of gliomas is possible. MATERIALS AND METHODS: 7T SWI was performed on 21 patients with gliomas before surgery with optimization for sharp visualization of the corticomedullary junction. Scoring for cortical thickening and displacement of medullary vessels, characteristic of oligodendroglial tumors, and cortical tapering, characteristic of astrocytic tumors, was performed. Additionally, characteristics of malignancy, including thickening of the medullary veins, the presence of microbleeds, and/or necrosis were scored. RESULTS: Scoring for oligodendroglial (highest possible score, +3) and astrocytic (lowest score possible, -3) characteristics yielded a significant difference between astrocytomas and oligodendrogliomas (mean, -1.93 versus +1.71, P < .01). Scoring for malignancy was significantly different among the World Health Organization grade II (n = 10), grade III (n = 4), and grade IV (n = 7) tumors (mean, 0.20 versus 1.38 versus 2.79). Cortical thickening was observed significantly more frequently in oligodendrogliomas (P < .02), with a sensitivity of 71.4% and specificity of 85.7%; observation of tapering of the cortex was higher in astrocytomas (P < .01) with a sensitivity of 85.7% and specificity of 100%. CONCLUSIONS: Visualization of the corticomedullary junction by 7T SWI was useful in distinguishing astrocytomas and oligodendrogliomas. Observation of tapering of the cortex was most sensitive and specific for diagnosing astrocytomas. Reliably predicting malignant grade was also possible by 7T SWI.

Tumor necrosis factor-α enhances RANKL expression in gingival epithelial cells via protein kinase A signaling.

OBJECTIVE AND BACKGROUND: Periodontitis is an inflammatory disorder of the supporting tissue of teeth, which is composed of gingival soft tissue, cementum covering the tooth root, alveolar bone and periodontal ligament. The receptor activator of nuclear factor kappa B ligand (RANKL) is known to be an essential factor for osteoclastogenesis. Recent clinical studies indicate that levels of RANKL in the gingival crevicular fluid are increased while levels of its decoy receptor, osteoprotegerin (OPG), are decreased in patients with periodontitis. Although the gingival sulcus is composed of gingival tissue, RANKL and OPG expression in gingival epithelial cells is not fully understood. The aim of this study is to investigate the expression of RANKL and OPG in gingival tissue and which factors regulate RANKL expression in gingival epithelial cells. MATERIAL AND METHODS: Reverse transcriptase polymerase chain reaction analysis, western blotting and immunohistochemistry were performed to confirm RANKL and OPG expression in gingival epithelial cells (GECs) and in gingival tissue. Immunostaining was also examined to confirm tumor necrosis factor (TNF)-α and TNF receptor type 1 (TNFR1) expression in gingival tissue. Ca9-22 cells, a human gingival epithelial cell line and human primary GECs were treated with TNF-α. Ca9-22 cells were treated by antibodies against TNF receptors, an inhibitor and an activator of protein kinase A (PKA) signaling and inhibitors of p38, Erk and NF-κB signaling to examine TNF-α-RANKL signaling pathways. RESULTS: RANKL mRNA and protein were expressed in GECs. Immunohistochemistry also showed RANKL expression in gingival tissue. On the other hand, the reverse transcriptase polymerase chain reaction and immunohistochemistry assay showed that GECs did not express OPG. In addition, TNF-α and TNFR1 proteins were expressed in junctional epithelium. TNF-α increased RANKL expression in GECs. TNF-α-induced RANKL expression was inhibited by an antibody against TNFR1 and an inhibitor of PKA signaling. Surprisingly, forskolin, a PKA activator, increased TNF-α-induced RANKL expression. CONCLUSION: RANKL, TNF and TNFR1 were coexpressed in junctional epithelium of gingival tissue. TNF-α induced RANKL expression via TNFR1 and PKA signaling in GECs of junctional epithelium.

The distribution and expression of S100A8 and S100A9 in gingival epithelium of mice.

OBJECTIVE AND BACKGROUND: Gingival epithelium protects against bacterial infection by producing antimicrobial peptides such as calprotectin. Calprotectin consists of proteins S100A8 and S100A9. Although in vitro assay has shown that neutrophils and gingival epithelial cells express calprotectin, the expression of S100A8 and S100A9 and colocalization of both S100 proteins in gingival tissue in vivo are not fully understood. The aim of this study was to investigate the distribution of S100A8 and S100A9 expression in gingival epithelium of mice in the presence and absence of infection. MATERIALS AND METHODS: A quantitative analysis of S100A8 and S100A9 mRNA in junctional epithelium (JE) and oral gingival epithelium (OGE) of both germ-free mice and conventional mice was performed using laser microdissection and real-time polymerase chain reaction (PCR). Confirmation of S100A8 and S100A9 mRNA expression in the JE was conducted by fluorescent immunohistochemistry. RESULTS: Real-time PCR analysis indicated that S100A8 and S100A9 expressions were mainly detected in JE and only slightly or not detected in OGE. Levels of both S100A8 and S100A9 mRNA expression in JE of conventional mice were significantly higher than those in JE of germ-free mice. Additionally, fluorescent immunohistochemistry showed that S100A8 expression was observed in the JE of both conventional and germ-free mice, whereas S100A9 was expressed in the JE of conventional but not germ-free mice. CONCLUSION: S100A8 protein is expressed in JE cells of mice in the presence and in the absence of infection with oral bacteria. S100A9 expression in JE cells in the presence of microflora is significantly increased compared with the absence of microflora, which suggests that S100A9 expression may be induced by infection of microflora. The production of calprotectin in gingival epithelial cells may be mediated through S100A9 induction by bacterial infection.

Role of the junctional epithelium in periodontal innate defense and homeostasis.

BACKGROUND AND OBJECTIVE: The junctional epithelium provides the front-line defense against periodontal bacterial infection. The migration of neutrophils into the junctional epithelium might represent a protective reaction against bacterial infections. However, neutrophils penetrate into the junctional epithelium even under sterile conditions. In this study, we analyzed and compared the number of neutrophils and the cytokine expression related to neutrophil migration in the junctional epithelium in conventional and germ-free mice. MATERIAL AND METHODS: Germ-free and conventional ICR mice were used at 12 wk of age. Frozen sections were used for the detection of Gr-1, macrophage inflammatory protein-2 (MIP-2/CXCL2) and proliferating cell nuclear antigen-positive cells in the two groups of mice. Laser capture microdissection and RT-PCR analysis were used to evaluate the expression of keratinocyte-derived chemokine (KC/CXCL1), MIP-2, interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α) mRNAs in the two groups of mice. RESULTS: Morphometric examination indicated an increase in the area of the junctional epithelium upon bacterial infection. Immunohistochemical studies also detected an increased number of neutrophils in the junctional epithelium upon bacterial infection. Higher up-regulation of KC and MIP-2 were detected in the junctional epithelium of conventional mice than in germ-free mice, whereas the expression of Il-1ß and Tnfα mRNAs was not affected. CONCLUSION: Junctional epithelium cells constitutively expressed several types of chemokines and cytokines and the expression of chemokines was augmented by bacterial infection. Therefore, the constitutive expression of cytokines in junctional epithelium might be related to the morphological and functional homeostasis of the junctional epithelium in addition to the defense against the bacterial infection.

Histological study of the nasal septal cartilage in BALB/c-bm/bm mouse which spontaneously induces malocclusion.

OBJECTIVES: The BALB/c-bm/bm mouse is characterized by short limbs and short tail attributed to undersulfated glycosaminoglycans. Anterior transverse crossbite sometimes spontaneously appears in BALB/c-bm/bm mice. The BALB/c-bm/bm mouse shows a short nose and cranium. The reason for hypo-growth of anterior craniofacial structures has not been clarified, although the nasal septal cartilage might be related to the growth of anterior craniofacial structures. Therefore, the purpose of this study was to evaluate histological findings of the nasal septal cartilage at the border region of the ethmoid and sphenoid bone in BALB/c-bm/bm mice. MATERIALS AND METHODS: BALB/c mice (wild type) and BALB/c-bm/bm mice with normal occlusion (bm/bm) were used. Sagittal sections of female mice aged 2, 4, and 8 weeks were stained with hematoxylin and eosin for histological analysis. RESULTS: At the border region between the nasal septal cartilage and the ethmoid bone in bm/bm, the area of proliferative zone was significantly smaller than that in wild type. At the border regions between the nasal septal cartilage and both the ethmoid and sphenoid bones, the number of proliferative chondrocytes was significantly smaller. Normal endochondral ossification was not observed at the border region between the nasal septal cartilage and the sphenoid bone in bm/bm. CONCLUSION: The findings suggest that disorder of endochondral ossification in the nasal septal cartilage contributes to the hypo-growth of anterior craniofacial structures in bm/bm.

Morphological evaluation of cranial and maxillary shape differences of the brachymorphic mouse with spontaneous malocclusion using three-dimensional micro-computed tomography.

OBJECTIVES: The aim of this study was to determine whether significant cranial and maxillary deformity exists in BALB/c-bm/bm (brachymorphism) mouse with spontaneous malocclusion using three-dimensional (3D) images. MATERIALS AND METHODS: Thirty female mice were divided into the following three groups: control group (BALB/c mice, n = 10), Norm group (BALB/c-bm/bm mice with normal occlusion, n = 10), and Mal group (BALB/c-bm/bm mice with malocclusion, n = 10). Nine points in the skull were selected, and transverse and antero-posterior distances were measured using three-dimensional images of micro-computed tomography (CT). Moreover, 3D images were superimposed at the median plane to visualize the skull shape asymmetry. RESULTS: The transverse distances at the posterior cranial and maxillary region and the antero-posterior distances in the Norm and Mal groups were significantly shorter than those in the control group. The nasal septum of the Mal group was significantly shorter than that of the Norm group. Morphological measurements and superimposed 3D images showed that lateral deviation occurred at the anterior cranial and maxillary region in the Mal group. CONCLUSION: The 3D micro-CT images revealed that the antero-posterior length and posterior transverse width at the cranium and maxilla in BALB/c-bm/bm mice were significantly smaller than those in BALB/c mice. It was quantitatively and morphologically clear that BALB/c-bm/bm mice show a spontaneous transverse crossbite owing to lateral deviation of the maxilla and nasal bone.

Serum adiponectin level is not only decreased in metabolic syndrome but also in borderline metabolic abnormalities.

OBJECTIVE: Along with the increasing prevalence of obesity and related diseases, particularly atherosclerotic diseases, metabolic syndrome (MetS) is now a common and major public health issue in many countries around the world. Adiponectin, a protein secreted by the adipose tissue, has become recognized as a key player in the development of MetS. These days, not only MetS but also borderline metabolic/physiological abnormalities, such as impaired fasting glucose, high normal blood pressure and high normal plasma cholesterol, have been reported to be risk factors for atherosclerotic disease. Therefore, we undertook this study to determine the relationship between adiponectin and borderline metabolic/physiological abnormalities, as well as MetS. DESIGN: A cross-sectional study performed from April 2007 to November 2009. SUBJECTS: In 16 892 Japanese adults (10 008 men and 6884 women), we examined the relationship between the serum adiponectin concentration and borderline metabolic/physiological abnormalities or MetS by a questionnaire survey about medical treatment, body size measurement and measurement of laboratory parameters including the serum adiponectin concentration. RESULTS: Adiponectin showed a significant negative correlation with the number of MetS components. In subjects without overt diabetes mellitus, hypertension or dyslipidemia, the adiponectin concentration also showed a significant negative correlation with the number of borderline metabolic abnormalities. CONCLUSION: The decrease of circulating adiponectin may start before the development of diabetes mellitus, hypertension, dyslipidemia or MetS. Adiponectin is an important biomarker for reflecting the adverse influence of visceral fat in persons with MetS, and also in these subclinical states.

Variations in otolith patterns, sizes and body morphometrics of jack mackerel Trachurus japonicus juveniles.

Variations in otolith patterns, sizes and body morphometrics of jack mackerel Trachurus japonicus juveniles were investigated. Under transmitted light, translucent (W(t)) and opaque otoliths (W(o)) were detected in juveniles collected from Wakasa Bay between July 2005 and April 2006, whereas only opaque otoliths (G(o)) were detected in Goto-nada Sea individuals between May and June 2006. Three groups of juveniles were distinguished based on differences in hatch season, otolith size and growth history, and body morphometrics. As T. japonicus has different spawning seasons according to spawning grounds, each group was estimated to hatch in different waters. Juveniles with W(t) otoliths were considered to have stayed in coastal habitat longer, as the hatch area was estimated to be near Wakasa Bay. Juveniles with W(o) and G(o) otoliths appear to recruit to coastal waters at larger size, since their hatch areas were estimated to be far from each collection area. Larger otoliths of W(t) were attributed to otolith accretion after the second growth flexion, which was observed only for W(t) . Standard length of W(t) fish at the second otolith growth flexion was estimated to correspond to recruitment size to coastal rocky reefs in Wakasa Bay. Body morphometrics were correlated with otolith size after removing body size effect, suggesting that morphological variations of T. japonicus juveniles were also associated with the timing of recruitment to coastal habitat.

Clinical relevance of cagPAI intactness in Helicobacter pylori isolates from Vietnam.

The purpose of this paper is to investigate the relationship between clinical outcome and the intactness of cagPAI in Helicobacter pylori strains from Vietnam. The presence or absence of 30 cagPAI genes was investigated by polymerase chain reaction (PCR) and dot-blotting. H. pylori-induced interleukin-8 secretion and hummingbird phenotype, and H. pylori adhesion to gastric epithelial cells were examined. The serum concentration of pepsinogen 1, pepsinogen 2, and gastrin was also measured in all patients. cagPAI was present in all 103 Vietnamese H. pylori isolates, of which 91 had intact cagPAI and 12 contained only a part of cagPAI. Infection with the partial cagPAI strains was less likely to be associated with peptic ulcer and chronic gastric mucosal inflammation than infection with strains possessing intact cagPAI. The partial cagPAI strains lacked almost all ability to induce interleukin-8 secretion and the hummingbird phenotype in gastric cells. Their adhesion to epithelial cells was significantly decreased in comparison with intact cagPAI strains. Moreover, for the first time, we found an association between cagPAI status and the serum concentration of pepsinogens 1 and 2 in infected patients. H. pylori strains with internal deletion within cagPAI are less virulent and, thus, less likely to be associated with severe clinical outcomes.

Helicobacter pylori dupA gene is not associated with clinical outcomes in the Japanese population.

The dupA gene of Helicobacter pylori was suggested to be a risk factor for duodenal ulcer but protective against gastric cancer. The present study aimed to re-examine the role of dupA in H. pylori-infected Japanese patients. We found that dupA status was not associated with any gastroduodenal disease, histological score of chronic gastritis or with the extent of interleukin-8 production from gastric cell lines. These results indicate that dupA is unlikely to be a virulence factor of H. pylori in the Japanese population.

Genome-wide microRNA expression profiling in renal cell carcinoma: significant down-regulation of miR-141 and miR-200c.

We investigated expression profiles of microRNA (miRNA) in renal cell carcinoma [clear cell carcinomas (CCC) and chromophobe renal cell carcinomas (ChCC)] and in normal kidneys by using a miRNA microarray platform which covers a total of 470 human miRNAs (Sanger miRBase release 9.1). Unsupervised hierarchical cluster analysis revealed that CCC and ChCC were separable and that no subgroups were identified in CCCs. We found that 43 miRNAs were differentially expressed between CCC and normal kidney, of which 37 were significantly down-regulated in CCC and the other 6 were up-regulated. We also found that 57 miRNAs were differentially expressed between ChCC and normal kidney, of which 51 were significantly down-regulated in ChCC and the other 6 were up-regulated. Together, these observations indicate that expression of miRNAs tends to be down-regulated in both CCC and ChCC compared with normal kidney. We observed that miR-141 and miR-200c were the most significantly down-regulated miRNAs in CCCs. Indeed, in all cases of CCC analysed, both miR-141 and miR-200c were down-regulated in comparison with normal kidney. Microarray data and quantitative RT-PCR showed that these two miRNAs were expressed concordantly. TargetScan algorithm revealed that ZFHX1B mRNA is a hypothetical target of both miR-141 and -200c. We established by quantitative RT-PCR that, in CCCs in which miR-141 and miR-200c were down-regulated, ZFHX1B, a transcriptional repressor for CDH1/E-cadherin, tended to be up-regulated. Furthermore, we found that overexpression of miR-141 and miR-200c caused down-regulation of ZFHX1B and up-regulation of E-cadherin in two renal carcinoma cell lines, ACHN and 786-O. On the basis of these findings, we suggest that down-regulation of miR-141 and miR-200c in CCCs might be involved in suppression of CDH1/E-cadherin transcription via up-regulation of ZFHX1B.

Genome-wide analysis of DNA copy number alterations and gene expression in gastric cancer.

Genomic copy number aberrations (CNAs) are believed to play a major role in the development and progression of human cancers. Although many CNAs have been reported in gastric cancer, their genome-wide transcriptional consequences are poorly understood. In this study, to reveal the impact of CNAs on genome-wide expression in gastric cancer, we analysed 30 cases of gastric cancers for their CNAs by array comparative genomic hybridization (array CGH) and 24 of these 30 cases for their expression profiles by oligonucleotide-expression microarray. We found that with the application of laser microdissection, most CNAs were detected at higher frequency than in previous studies. Notably, gain at 20q13 was detected in almost all cases (97%), suggesting that this may play an important role in the pathogenesis of gastric cancer. By comparing the array CGH data with expression profiles of the same samples, we showed that both genomic amplification and deletion strongly influence the expression of genes in altered genomic regions. Furthermore, we identified 125 candidate genes, consisting of 114 up-regulated genes located in recurrent regions (>10%) of amplification and 11 down-regulated genes located in recurrent regions of deletion. Up-regulation of several candidate genes, such as CDC6, SEC61G, ANP32E, BYSL and FDFT1, was confirmed by immunohistochemistry. Interestingly, some candidate genes were localized at genomic loci adjacent to well-known genes such as EGFR, ERBB2 and SMAD4, and concordantly deregulated by genomic alterations. Based on these results, we propose that our list of candidate genes may contain novel genes involved in the pathogenesis of advanced gastric cancer.

High-resolution analysis of DNA copy number alterations and gene expression in renal clear cell carcinoma.

We analysed chromosomal copy number aberrations (CNAs) in renal cell carcinomas by array-based comparative genomic hybridization, using a genome-wide scanning array with 2304 BAC and PAC clones covering the whole human genome at a resolution of roughly 1.3 Mb. A total of 30 samples of renal cell carcinoma were analysed, including 26 cases of clear cell carcinoma (CCC) and four cases of chromophobe renal cell carcinoma (ChCC). In CCCs, gains of chromosomes 5q33.1-qter (58%), 7q11.22-q35 (35%) and 16p12.3-p13.12 (19%), and losses of chromosomes 3p25.1-p25.3 (77%), 3p21.31-p22.3 (81%), 3p14.1-p14.2 (77%), 8p23.3 (31%), 9q21.13-qter (19%) and 14q32.32-qter (38%) were detected. On the other hand, the patterns of CNAs differed markedly between CCCs and ChCCs. Next, we examined the correlation of CNAs with expression profiles in the same tumour samples in 22/26 cases of CCC, using oligonucleotide microarray. We extracted genes that were differentially expressed between cases with and without CNAs, and found that significantly more up-regulated genes were localized on chromosomes 5 and 7, where recurrent genomic gains have been detected. Conversely, significantly more down-regulated genes were localized on chromosomes 14 and 3, where recurrent genomic losses have been detected. These results revealed that CNAs were correlated with deregulation of gene expression in CCCs. Furthermore, we compared the patterns of genomic imbalance with histopathological features, and found that loss of 14q appeared to be a specific and additional genetic abnormality in high-grade CCC. When we compared the expression profiles of low-grade CCCs with those of high-grade CCCs, differentially down-regulated genes tended to be localized on chromosomes 14 and 9. Thus, it is suggested that copy number loss at 14q in high-grade CCC may be involved in the down-regulation of genes located in this region.

[Extrapleural pneumonectomy for relapsed solitary fibrous tumors of the pleura with pleural dissemination].

We report a case of a 62-year-old female with a prior thoracotomy for solitary fibrous tumor of the diaphragmatic pleura. There was no clear evidence of malignant solitary fibrous tumor of the pleura (SFTP). In the 19th postoperative month, she had a disseminated recurrence of SFTP in the left thoracic cavity. There was no evidence of metastasis from medical imaging. Accordingly, a left extrapleural pneumonectomy was performed. Pathological examination revealed a disseminated recurrence of malignant SFTP, showing a higher grade of malignancy, because the resected specimen was identical to the only section suspicious of malignancy in the previous tumor. She had no complaint and kept better performance status until the 7th postoperative month after the re-resection, when she had a recurrence in the left thoracic cavity and dissemination in the peritoneal cavity. She died of the recurrence 15 months after the re-resection and 34 months after the prior thoracotomy.

Real-time PCR quantification of nitrite reductase (nirS) genes in a nitrogen removing fluidized bed reactor.

Molecular approaches were applied to identify and enumerate denitrifying bacteria subsisting in a fluidized bed reactor (FBR). The FBR was continuously operated as a unit for the removal of nitrogen from the effluents of domestic sewage treatment plant, with an additional supply of methanol as a carbon source. By denaturing gradient gel electrophoresis (DGGE) and sequence analysis of 16S ribosomal RNA genes, Thauera group was found to be dominant among the denitrifying bacteria in the FBR sludge. Oligonucleotide probe THA155 for fluorescence in situ hybridization (FISH) was newly designed for specifically targeting the Thauera group. However, the THA155 signal obtained from the sludge was only 0.9-5.7% of the DAPI-stained total cells. The real-time polymerase chain reaction (PCR) targeting the sequences of nitrite reductase (NIR) gene, a key enzyme of denitrification processes, was performed to quantify the cells of denitrifying bacteria cells including the Thauera group in FBR sludge. An excellent correlation was obtained between the numbers of nirS genes and the activity of denitrifiers in the FBR sludge.

Tumour lines from a spontaneous rat endometrial stromal sarcoma, showing dendritic cell-like and myofibroblastic cell-like phenotypes.

A transplantable tumour (RY) and cell lines (RY-PB and clone RY-B-E3 isolated from RY-PB) were established from a naturally occurring endometrial stromal sarcoma (ESS) found in a 24-month-old female F344 rat. The primary tumour and RY tumours, which had been serially passaged in syngeneic female rats up to the 10th generation, consisted of spindle or round cells arranged in ill-defined bundles or sheets. Neoplastic cells of the primary and RY tumours, as well as cultured cells of RY-PB and RY-B-E3, showed positive reactions to vimentin, ED1/ED2 (both for rat macrophages/histiocytes), OX6 (for dendritic cells expressing rat MHC class II antigens), and lysosomal enzymes such as acid phosphatase and non-specific esterase, in varying degrees. Ultrastructurally, neoplastic cells characteristically had tubulovesicular system-like structures and variously developed lysosomes in the cytoplasm. Neoplastic cells also exhibited immunoexpression to an alpha-smooth muscle actin (alpha-SMA). The addition of transforming growth factor (TGF)-beta1 to RY-PB and RY-B-E3 cultures increased the number of alpha-SMA-positive cells, whilst the positive cell number was decreased by anti-TGF-beta antibody. The RT-PCR method revealed the expression of TGF-beta1 mRNA in the cultured cells. The present study showed that rat ESS-derived cells exhibited dendritic cell-like and myofibroblastic cell-like phenotypes. The histogenesis of ESSs in human beings and rats remains poorly understood, and these tumour lines may therefore become useful tools for further research.

Synaptically activated Cl- accumulation responsible for depolarizing GABAergic responses in mature hippocampal neurons.

It is known that GABA, a major inhibitory transmitter in the CNS, acts as an excitatory (or depolarizing) transmitter transiently after intense GABAA receptor activation in adult brains. The depolarizing effect is considered to be dependent on two GABAA receptor-permeable anions, chloride (Cl-) and bicarbonate (HCO3-). However, little is known about their spatial and temporal profiles during the GABAergic depolarization in postsynaptic neurons. In the present study, we show that the amplitude of synaptically induced depolarizing response was correlated with intracellular Cl- accumulation in the soma of mature hippocampal CA1 pyramidal cells, by using whole cell patch-clamp recording and Cl- imaging technique with a Cl- indicator 6-methoxy-N-ethylquinolinium iodide (MEQ). The synaptically activated Cl- accumulation was mediated dominantly through GABAA receptors. Basket cells, a subclass of fast-spiking interneurons innervating the somatic portion of the pyramidal cells, actually fired at high frequency during the Cl- accumulation accompanying the depolarizing responses. These results suggest synaptically activated GABAA-mediated Cl- accumulation may play a critical role in generation of an excitatory GABAergic response in the mature pyramidal cells receiving intense synaptic inputs. This may be the first demonstration of microscopic visualization of intracellular Cl- accumulation during synaptic activation.

Characterization of newly established tumor lines from a spontaneous malignant schwannoma in F344 rats: nerve growth factor production, growth inhibition by transforming growth factor-beta1, and macrophage-like phenotype expression.

Transplantable tumor (KE) and clone cell (KE-F11) lines were established from a spontaneous malignant schwannoma found in an aged F344 rat. The primary tumor and KE tumors consisted of oval or spindle cells arranged in ill-defined bundles. Cultured KE-F11 cells exhibited polygonal or spindle configurations. Immunohistochemically, neoplastic cells in KE and KE-F11 reacted to vimentin, S-100 protein, neuron-specific enolase, myelin basic protein, and glial fibrillary acidic protein in varying degrees, indicating neurogenic features; occasional cells reacted to alpha-smooth muscle actin. Cells positive for lysosomal enzymes (acid phosphatase and non-specific esterase), and ED1 (rat macrophage specific) were observed in KE-F11, and electron microscopically, cells with many lysosomes were frequently present, indicating expression of macrophage-like phenotypes. Bioassay analysis revealed that KE-F11 cells produced high levels of nerve growth factor. DNA synthesis was inhibited by addition of transforming growth factor-beta1 (TGF-beta1), and Northern blot analysis revealed that expression of c-myc, a cell cycle-related immediate early gene, was depressed by TGF-beta1. Likely, TGF-beta1 is a factor capable of inhibiting cellular growth of Schwann cells. mRNA expression of the low-density lipoprotein receptor-related protein (LRP) was seen in KE-F11 cells by Northern blot analysis, and the level was decreased by lipopolysaccharide (LPS) treatment. LRP may be attributable to regulation of Schwann cell functions. KE-F11 cells seeded on laminin-coated dishes exhibited more extended cytoplasmic projections than on collagen type I-coated dishes. The present study provides evidence that biological properties of malignant schwannoma-derived cells might be affected by exogenous factors such as TGF-beta1, LPS and laminin. These tumor lines may be useful for studies on pathobiological characteristics of Schwann cells.