Expression status of p16 protein is associated with human papillomavirus oncogenic potential in cervical and genital lesions

The p16 protein (p16) is a cyclin-dependent kinase (CDK) inhibitor that decelerates the cell cycle by inactivating the CDKs that phosphorylate retinoblastoma (Rb) protein. Recent biological studies have revealed that p16 expression is markedly influenced by the status of Rb expression, and p16 overexpression has been demonstrated in cervical cancers because of functional inactivation of Rb by human papillomavirus (HPV) E7 protein. To clarify the relationship between p16 overexpression and HPV infection in cervical carcinogenesis, immunohistochemical analysis of p16 and detection of HPV by in situ hybridization and polymerase chain reaction were performed on 139 formalin-fixed and paraffin-embedded samples of cervical and genital condylomatous and neoplastic lesions. Marked overexpression of p16 protein, ie, diffuse and strong immunostaining, was observed in all cervical cancers and preneoplastic lesions with infection by high- and intermediate-risk HPVs, ie, subtypes 16, 18, 31, 33, 52, and 58. Condylomata acuminata and low-grade squamous intraepithelial lesions with infection by low-risk HPV such as HPV-6/11 showed focal and weak immunohistochemical staining for p16. Our results clearly showed that the mode of p16 expression in lesions with high- and intermediate-risk HPVs differed from its expression in lesions with low-risk HPVs and thus might be attributable to differences in functional inactivation of Rb protein by different HPVs.

Allergic Rhinitis and its Impact on Asthma (ARIA): achievements in 10 years and future needs

Allergic rhinitis (AR) and asthma represent global health problems for all age groups. Asthma and rhinitis frequently coexist in the same subjects. Allergic Rhinitis and its Impact on Asthma (ARIA) was initiated during a World Health Organization workshop in 1999 (published in 2001). ARIA has reclassified AR as mild/moderate-severe and intermittent/persistent. This classification closely reflects patients' needs and underlines the close relationship between rhinitis and asthma. Patients, clinicians, and other health care professionals are confronted with various treatment choices for the management of AR. This contributes to considerable variation in clinical practice, and worldwide, patients, clinicians, and other health care professionals are faced with uncertainty about the relative merits and downsides of the various treatment options. In its 2010 Revision, ARIA developed clinical practice guidelines for the management of AR and asthma comorbidities based on the Grading of Recommendation, Assessment, Development and Evaluation (GRADE) system. ARIA is disseminated and implemented in more than 50 countries of the world. Ten years after the publication of the ARIA World Health Organization workshop report, it is important to make a summary of its achievements and identify the still unmet clinical, research, and implementation needs to strengthen the 2011 European Union Priority on allergy and asthma in children.

High expression of vascular endothelial growth factor is associated with liver metastasis and a poor prognosis for patients with ductal pancreatic adenocarcinoma

BACKGROUND

Vascular endothelial growth factor (VEGF), a recently identified growth factor with significant angiogenic properties, is a multifunctional angiogenic cytokine that is expressed in many tumors. High VEGF expression has been shown to correlate with the incidence of metastasis and poor prognosis in various cancers. In this study, the authors investigated VEGF expression and microvessel density (MVD) in ductal pancreatic adenocarcinoma and examined the correlations among VEGF expression, clinicopathologic factors, and clinical outcome. The authors especially focused on the correlation between VEGF expression and liver metastasis.

METHODS

Paraffin embedded tumor specimens of 142 surgically resected pancreas carcinoma were immunohistochemically stained for VEGF and MVD. The correlations among VEGF expression and MVD, clinicopathologic factors, and clinical outcome were then statistically analyzed.

RESULTS

One hundred thirty-two (93%) of 142 ductal pancreatic adenocarcinomas were positive for VEGF protein by immunohistochemistry. A significant correlation was observed between VEGF positivity and MVD (P < 0.0001). Multivariate logistic regression analysis indicated a significant association between high VEGF expression and liver metastasis (P = 0.010) but no other factors, such as age, tumor size, histologic type, lymph node metastasis, venous invasion, neural invasion, peritoneal metastasis, or local recurrence. Patients with tumors that showed moderate or high VEGF expression had significantly shorter survival than patients with low VEGF expression or none at all in their tumors (P < 0.05).

CONCLUSIONS

These results indicate that VEGF expression is closely correlated with MVD and seems to be an important predictor for both liver metastasis and poor prognosis in ductal pancreatic adenocarcinoma.

Disruption of the Bcl6 gene results in an impaired germinal center formation

The Bcl6 gene has been identified from the chromosomal translocation breakpoint in B cell lymphomas, and its products are expressed highly in germinal center (GC) B cells. To investigate the function of Bcl6 in lymphocytes, we have generated RAG1-deficient mice reconstituted with bone marrow cells from Bcl6-deficient mice (Bcl6(-/-)RM). Lymphogenesis in primary lymphoid tissues of Bcl6(-/-)RM is normal, and Bcl6(-/-)RM produced control levels of primary IgG1 antibodies specific to T cell-dependent antigens. However, GCs were not found in these mice. This defect was mainly due to the abnormalities of B cells. Therefore, Bcl6 is essential for the differentiation of GC B cells.

A novel mitochondrial ubiquitin ligase plays a critical role in mitochondrial dynamics

In this study, we have identified a novel mitochondrial ubiquitin ligase, designated MITOL, which is localized in the mitochondrial outer membrane. MITOL possesses a Plant Homeo-Domain (PHD) motif responsible for E3 ubiquitin ligase activity and predicted four-transmembrane domains. MITOL displayed a rapid degradation by autoubiquitination activity in a PHD-dependent manner. HeLa cells stably expressing a MITOL mutant lacking ubiquitin ligase activity or MITOL-deficient cells by small interfering RNA showed an aberrant mitochondrial morphology such as fragmentation, suggesting the enhancement of mitochondrial fission by MITOL dysfunction. Indeed, a dominant-negative expression of Drp1 mutant blocked mitochondrial fragmentation induced by MITOL depletion. We found that MITOL associated with and ubiquitinated mitochondrial fission protein hFis1 and Drp1. Pulse-chase experiment showed that MITOL overexpression increased turnover of these fission proteins. In addition, overexpression phenotype of hFis1 could be reverted by MITOL co-overexpression. Our finding indicates that MITOL plays a critical role in mitochondrial dynamics through the control of mitochondrial fission proteins.

Multistage regulation of Th1-type immune responses by the transcription factor IRF-1

Eradication of a given pathogen is dependent on the selective differentiation of T helper (Th) cells into Th1 or Th2 types. We show here that T cells from mice lacking the transcription factor IRF-1 fail to mount Th1 responses and instead exclusively undergo Th2 differentiation in vitro. Compromised Th1 differentiation is found to be associated with defects in multiple cell types, namely impaired production of interleukin-12 by macrophages, hyporesponsiveness of CD4+ T cells to interleukin-12, and defective development of natural killer cells. These results indicate the involvement of IRF-1 in multiple stages of the Th1 limb of the immune response.

Long-term results of balloon-occluded retrograde transvenous obliteration for the treatment of gastric varices and hepatic encephalopathy

PURPOSE

To evaluate the long-term results of balloon-occluded retrograde transvenous obliteration (B-RTO) for the treatment of gastric varices (GV) and hepatic encephalopathy.

MATERIALS AND METHODS

A total of 43 patients who had undergone B-RTO were evaluated, 32 with GV, two with hepatic encephalopathy, and nine with both. All but one had been consecutively followed up with gastrointestinal endoscopy for more than 1 year (3-60 months; mean, 30.44 months). Collateral veins of gastric varices were graded using balloon-occluded retrograde left adrenal venography. The relation of both worsening of esophageal varices (EV) and improved Child-Pugh score after B-RTO to the grades of collateral vein development was analyzed. The relapse-free survival and the prognostic factors for survival after B-RTO were also assessed.

RESULTS

GV disappeared or decreased markedly in size, and hepatic encephalopathy was completely cured in all patients. Improvement in Child-Pugh score was observed in 21 patient (50.0%) 6 months after B-RTO, but in only 11 patients (25.6%) 1 year after B-RTO. Worsening of EV was seen in eight patients and was related to a worsened grade of collateral veins. Cumulative relapse-free survival rate was 90.8% at 1 year and 87.4% at 3 years after B-RTO. The most significant prognostic factor was Child-Pugh classification (relative risk: 4.16)

CONCLUSION

B-RTO is a safe and effective treatment for patients with GV and hepatic encephalopathy. The most important prognostic factors are the extent of Child-Pugh classification.

Expression of glucose transporter-1 in human gastric carcinoma: association with tumor aggressiveness, metastasis, and patient survival

BACKGROUND

Malignant cells show increased glucose uptake in vitro and in vivo, which is believed to be facilitated by glucose transporters (Gluts). Expression of Glut1, one of the Gluts, has been described in malignancies of the esophagus, colon, pancreas, lung, and brain, but to the authors' knowledge the significance of Glut1 expression in human gastric carcinoma has not been elucidated. The objective of the current study was to examine the expression and distribution of Glut1 and its relation to clinicopathologic parameters in patients with gastric carcinoma.

METHODS

Immunohistochemistry with anti-Glut1 antibody was performed on 617 gastric carcinomas and 50 tubular adenomas of the stomach. Glut1-positive and Glut1-negative carcinomas were analyzed for their clinicopathologic characteristics including histologic subtype, depth of invasion, vascular permeation, lymph node and hepatic metastasis, peritoneal dissemination, and prognosis.

RESULTS

None of the adenomas expressed Glut1, whereas 182 of 617 carcinomas (29.5%) were positive for the protein. Signet ring cell carcinoma and mucinous adenocarcinoma rarely were positive (2.0% and 6.3%, respectively) and papillary adenocarcinoma (44%) showed slightly higher positivity for Glut1 than tubular (32%) or poorly differentiated adenocarcinoma (28%). Glut1-positive tumor cells were localized mainly in the central part of tumor nests with or without peripheral distribution (92%) but peripheral distribution alone was very limited (8%) (P = 0.0001). Glut1 positivity was associated with depth of invasion (P = 0.0001), lymphatic permeation (P = 0.0001), venous invasion (P = 0.0001), lymph node metastasis (P = 0.0001), hepatic metastasis (P = 0.0001), and carcinoma stage (P = 0.0001). However, peritoneal dissemination was not found to be associated with Glut1 positivity (P = 0.0833). The survival of patients who had tumors that expressed Glut1 was significantly shorter than that of patients with Glut1-negative tumors (P = 0.0001).

CONCLUSIONS

In human gastric carcinoma, Glut1 is expressed late in carcinogesis and increases with disease progression. Glut1 expression is associated with tumor aggressiveness and patient survival.

The effect of antimicrobial periodontal treatment on circulating tumor necrosis factor-alpha and glycated hemoglobin level in patients with type 2 diabetes

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha) may play an important role in insulin resistance. In this study, we hypothesized that TNF-alpha produced due to periodontal inflammation synergistically affects insulin resistance as well as TNF-alpha produced from adipose tissues in insulin-resistant type 2 diabetes patients. Therefore, to understand the effects of antimicrobial periodontal therapy on serum TNF-alpha concentration and subsequent metabolic control of diabetes, we examined the periodontal and diabetic status on 13 type-2 diabetes patients.

METHODS

These patients were treated with local minocycline administration in every periodontal pocket around all existing teeth once a week for a month. Before and after treatment, the number of total bacteria in the periodontal pockets and circulating TNF-alpha concentration were measured and the HbA1c value was assessed.

RESULTS

Antimicrobial therapy significantly reduced the number of microorganisms in periodontal pockets (P <0.01). After treatment, the circulating TNF-alpha level was significantly reduced (P <0.015). The HbA1c value was also reduced significantly (P <0.007). In addition, the 6 patients who were not receiving insulin therapy demonstrated decreased fasting insulin levels (P <0.03), and HOMA-R (P <0.03) indices. The average reductions in circulating TNF-alpha concentration and HbA1c value were 0.49 pg/ml and 0.8%, respectively.

CONCLUSION

The results indicate that anti-infectious treatment is effective in improving metabolic control in diabetics, possibly through reduced serum TNF-alpha and improved insulin resistance.

Complications associated with transcatheter arterial embolization for hepatic tumors

Transcatheter arterial embolization (TAE) is widely used in the treatment of hepatic tumors. A total of 2,300 TAE procedures were performed with a 2-15-mL injection of a mixture or suspension of anticancer drugs and iodized oil, followed by administration of gelatin sponge particles. One or two chemotherapeutic drugs, including doxorubicin hydrochloride (10-30 mg), epirubicin hydrochloride (10-30 mg), mitomycin C (10-20 mg), and cisplatin (25-100 mg), were used for each procedure. Complications were encountered in 4.4% of cases (n = 102) and were related to the use of chemoembolic agents or the manipulation of a catheter or guide wire. These complications included acute hepatic failure (n = 6), liver infarction (n = 4) or abscess (n = 5), intrahepatic biloma (n = 20), multiple intrahepatic aneurysms (n = 6), cholecystitis (n = 7), splenic infarction (n = 2), gastrointestinal mucosal lesions (n = 5), pulmonary embolism or infarction (n = 4), tumor rupture (n = 1), variceal bleeding (n = 3), and iatrogenic dissection (n = 35) or perforation (n = 4) of the celiac artery and its branches. Knowledge of these complications is important for correct diagnosis and appropriate management.

Preferential localization of c-kit product in tissue mast cells, basal cells of skin, epithelial cells of breast, small cell lung carcinoma and seminoma/dysgerminoma in human: immunohistochemical study on formalin-fixed, paraffin-embedded tissues

Eighteen hundred and eighty-four cases of human solid tumours and 833 samples of normal human tissues, formalin-fixed and paraffin-embedded, were examined immunohistochemically for expression of c-kit oncogene product using polyclonal antibody against synthesized c-kit peptide. Seminoma/dysgerminoma and small cell lung carcinoma (SCLC) show preferential c-kit expression at 92% and 36% frequency, respectively, whereas only sporadic cases of cervical carcinoma and non-SCLC lung carcinoma show c-kit positivity. A normal tissue counterpart positive for c-kit product is detected in the testis (spermatocyte) and ovary (oocyte) but not in the lung or the cervix. In contrast, normal epithelial cells of the breast, skin basal cells and tissue mast cells harbour c-kit product, but transformed cells of the former two are largely deficient in the c-kit protein. One hundred and thirty-nine neuroendocrine tumours and 39 non-pulmonary small cell carcinomas were all negative, except for two cases of neuroblastoma. This indicates a distinct character for SCLC in c-kit expression. The c-kit product may be a useful marker in diagnostic pathology of seminoma/dysgerminoma and SCLC among human solid tumours, and in distinction of SCLC from non-pulmonary small cell carcinoma.

Airway hyperresponsiveness, increased intracellular spaces of bronchial epithelium, and increased infiltration of eosinophils and lymphocytes in bronchial mucosa in asthma

Inflammation of the airway wall and airway hyperresponsiveness are consistent features of chronic asthma. We investigated how damage of the bronchial epithelium is related to airway hyperresponsiveness and how bronchial infiltration of eosinophils and lymphocytes is related to bronchial epithelial damage. We examined the biopsy specimens of bronchial mucosa taken from 19 patients with chronic asthma by electron microscopy. We also measured the incidence of opening of epithelial tight junctions, the widening of intercellular spaces in the epithelium, and the density of infiltrated eosinophils and lymphocytes in bronchial mucosa. Airway responsiveness was accessed by measuring PC20-acetylcholine (PC20-ACh). The inflammatory cells in the airway mucosa were counted by electron microscopy. Lymphocytes were most abundant, being 54.5% of the cells counted; eosinophils were 22.1%, neutrophils were 4.9%, and mast cells were 4.6%. A significant correlation was noted between the density of eosinophils and that of lymphocytes infiltrated in the airway mucosa (r = 0.80, p less than 0.01), suggesting that T cells may potentiate eosinophil infiltration. With increased density of eosinophils infiltrated in bronchial mucosa, both the incidence of opening of tight junctions of epithelial ciliary cells and the degree of widening of intercellular spaces in epithelium increased significantly (r = 0.51, p less than 0.05; r = 0.52, p less than 0.05), suggesting that eosinophils are related to damage of the bronchial epithelium. No correlation was observed between the density of lymphocyte infiltration and the degree of epithelial damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Modulation of cell-adhesive activity of fibronectin by the alternatively spliced EDA segment

Fibronectin (FN) has a complex pattern of alternative splicing at the mRNA level. One of the alternatively spliced segments, EDA, is prominently expressed during biological processes involving substantial cell migration and proliferation, such as embryonic development, malignant transformation, and wound healing. To examine the function of the EDA segment, we overexpressed recombinant FN isoforms with or without EDA in CHO cells and compared their cell-adhesive activities using purified proteins. EDA+ FN was significantly more potent than EDA- FN in promoting cell spreading and cell migration, irrespective of the presence or absence of a second alternatively spliced segment, EDB. The cell spreading activity of EDA+ FN was not affected by antibodies recognizing the EDA segment but was abolished by antibodies against integrin alpha5 and beta1 subunits and by Gly-Arg-Gly-Asp-Ser-Pro peptide, indicating that the EDA segment enhanced the cell-adhesive activity of FN by potentiating the interaction of FN with integrin alpha5beta1. In support of this conclusion, purified integrin alpha5beta1 bound more avidly to EDA+ FN than to EDA- FN. Augmentation of integrin binding by the EDA segment was, however, observed only in the context of the intact FN molecule, since the difference in integrin-binding activity between EDA+ FN and EDA- FN was abolished after limited proteolysis with thermolysin. Consistent with this observation, binding of integrin alpha5beta1 to a recombinant FN fragment, consisting of the central cell-binding domain and the adjacent heparin-binding domain Hep2, was not affected by insertion of the EDA segment. Since the insertion of an extra type III module such as EDA into an array of repeated type III modules is expected to rotate the polypeptide up to 180 degrees at the position of the insertion, the conformation of the FN molecule may be globally altered upon insertion of the EDA segment, resulting in an increased exposure of the RGD motif in III10 module and/or local unfolding of the module. Our results suggest that alternative splicing at the EDA exon is a novel mechanism for up-regulating integrin-binding affinity of FN operating when enhanced migration and proliferation of cells are required.

Intravascular ultrasound of coronary arteries in children. Assessment of the wall morphology and the lumen after Kawasaki disease

BACKGROUND

The long-term clinical issue in Kawasaki disease (KD) concerns the coronary artery lesion. Two-dimensional echocardiography and coronary angiography are routine examinations to evaluate the coronary lesions; however, these are not adequate to assess the wall morphology of the coronary artery (CA). Intravascular ultrasound imaging (IVUS), a new technology for the evaluation of the coronary artery lumen and wall morphology in vivo, was performed for patients after KD in their long-term follow-up, and we examined the new insights it gave.

METHODS AND RESULTS

IVUS was performed during cardiac catheterization in 20 subjects (10 patients after KD who still had coronary aneurysms or regressed coronary aneurysms, 2 after KD who had no coronary abnormal lesion, and 8 control patients with congenital heart disease and normal CA). We evaluated the wall structure at 10 to 15 sites of the CA in each patient. IVUS was performed with a commercially available ultrasound imaging catheter. Four sites of a CA aneurysm in KD demonstrated a markedly dilated lumen without thickened intima. One site of a CA aneurysm with calcification demonstrated an asymmetrical lumen by a dense echo with acoustic shadows. Twenty-two sites of a regressed CA aneurysm demonstrated a marked symmetrical or asymmetrical thickening of the intima with a dense echo, in which the size of the lumen was similar to that at a site near a regressed aneurysm. The sites of angiographically normal CA revealed normal structures and a thin intima in many instances. Nine of 28 sites in KD with a CA abnormal lesion, particularly near a coronary aneurysm or regressed aneurysm, demonstrated a mild thickening of the intima. All the 10 sites in KD without a CA abnormal lesion and all the 25 sites in patients with congenital heart disease with normal CA demonstrated a smooth intima.

CONCLUSIONS

This study demonstrated that the site of a regressed coronary aneurysm has a markedly thickened but smooth intima. The sites of angiographically normal CA after KD with or without a coronary lesion demonstrated normal IVUS findings in most instances but in some cases revealed a mild intimal thickening. IVUS is useful to evaluate the CA wall morphology and may contribute to the assessment of long-term CA sequelae and the possible development of arteriosclerotic changes in KD.

Interaction with P-glycoprotein and transport of erythromycin, midazolam and ketoconazole in Caco-2 cells

The effect of cytochrome P-450 3A (CYP3A) substrates (erythromycin, midazolam) and an inhibitor (ketoconazole) on P-glycoprotein-mediated transport was studied in Caco-2, the human colon adenocarcinoma cell line expressing various functions of differentiated intestinal epithelial cells. The involvement of P-glycoprotein in the transport of these drugs was also examined. The basal-to-apical transport of rhodamine 123, a P-glycoprotein substrate, was inhibited by erythromycin, midazolam and ketoconazole, as well as by P-glycoprotein inhibitors such as verapamil. The apical-to-basal transport of rhodamine 123 was increased by these drugs. The transepithelial transport of erythromycin and midazolam, but not of ketoconazole, was much greater from the basal to apical side than from the apical to basal side. The inhibitory effect of verapamil was observed on the basal to apical transport of erythromycin, but not on midazolam and ketoconazole transport. In conclusion, erythromycin, midazolam and ketoconazole could interact with P-glycoprotein-mediated transport, and P-glycoprotein could be, at least in part, involved in the transport of erythromycin, but not of midazolam and ketoconazole, in the intestinal epithelia.

Fatty acid synthase is expressed mainly in adult hormone-sensitive cells or cells with high lipid metabolism and in proliferating fetal cells

Animal fatty acid synthase (FAS) is a homodimer protein which synthesizes long-chain fatty acids and is rich in liver, brain, breast, and lung. However, the precise cellular localization of FAS in human tissues has not been elucidated. Immunohistochemistry with a new antibody to human FAS revealed that in adult human tissues FAS is distributed mainly in cells with high lipid metabolism (adipocytes, corpus luteum, hepatocytes, sebaceous glands, and Type II alveolar cells), in hormone-sensitive cells (anterior pituitary, apocrine gland, breast, endometrium, prostate, seminal vesicle, and adrenal cortex), and in a subset of epithelial cells of duodenum and stomach, colon absorptive cells, cerebral neurons, basket cells of cerebellum, decidua, uroepithelium, and epidymis. In fetal cells at 20 weeks of gestation, FAS was mainly present in proliferative epithelial cells of the digestive and respiratory systems, proximal renal tubules, adrenocortical cells, and mesenchymal and hematolymphoid cells. Staining was significant in nonproliferating cells, as observed in adult, and in sympathetic ganglion cells, Leidig cells of testis, and Langhans cells of chorionic villi. FAS is maintained in hormone-sensitive cells and/or cells active in lipid metabolism in the adult and is expressed in proliferating cells in the fetus, suggesting active fatty acid synthesis for energy utilization or membrane lipids.

Histologic evidence of absorption of sequestration-type herniated disc

STUDY DESIGN

The reactions to sequestrated disc fragments, which were removed surgically from 35 patients, were examined histologically.

OBJECTIVES

To elucidate whether or not there is histologic evidence of absorption of sequestrated discs.

SUMMARY OF BACKGROUND DATA

Spontaneous disappearance or diminution of lumbar herniated discs in the spinal canal has been recognized, and this could be a possible explanation for relief of symptoms without surgery. The mechanism of this phenomenon is unclear.

METHODS

Sequestrated discs removed surgically from 35 patients were examined histologically.

RESULTS

In 30 cases, neovascularization was observed at the periphery of the sequestrated discs. Many foamy cells (macrophages) were present in the vascularized areas. In addition, immunohistochemistry revealed that many spindle-shaped, fibroblast-like cells were positive for CD68, a marker of macrophages. No fibrous scar formation was observed in any region.

CONCLUSION

These findings suggest that organization is not a main course for this type of herniated disc and that a kind of "absorption" process occurs predominantly in the healing stage.

High-speed separation system of randomly suspended single living cells by laser trap and dielectrophoresis

We developed a new system for random separation of a single microorganism, such as a living cell and a microbe, in the microfluidic device under the microscope by integrating the laser-trapping force and dielectrophoretic (DEP) force. An arbitrarily selected single microbe could be isolated in a microchannel, despite the presence of a large number of microbes in solution. Once the target microbe is trapped at the focal point of the laser, we can easily realize exclusion of excess microbes around the target by controlling the electric field, while keeping the target trapped by the laser at the focal point. To realize an efficient separation system, we proposed a new separation cell and produced it by microfabrication. Flow speed in the microchannel is adjusted and balanced to realize high-speed and high-purity extraction of the target. Some preliminary experiments are conducted to show the effectiveness. The target is trapped by the laser, transported, and is taken out from the extraction port. Total separation time is less than 20 s. Our method is extremely useful in the pure cultivation of the cell and will be a promising method for biologists in screening useful microbes.

Rapid induction of more malignant tumors by various genotoxic carcinogens in transgenic mice harboring a human prototype c-Ha-ras gene than in control non-transgenic mice

In this study, we investigated the carcinogenic response of transgenic mice carrying the human prototype c-Ha-ras gene, namely Tg rasH2/CB6F1 mice, to various genotoxic carcinogens and compared it with that of control non-transgenic CB6F1 mice (non-Tg mice). The present studies were conducted as the first step in the evaluation of the Tg rasH2/CB6F1 mouse as a model for the rapid carcinogenicity testing system. Short-term (< or = 6 months) rapid carcinogenicity tests of various genotoxic carcinogens, 4-nitroquinoline-1-oxide, cyclophosphamide, N,N-diethylnitrosamine, N-methyl-N-nitrosourea, N-methyl-N'-nitro-N-nitrosoguanidine and methylazoxymethanol, revealed that Tg rasH2/CB6F1 mice are more susceptible to these genotoxic carcinogens than control non-Tg mice. Tg rasH2/CB6F1 mice developed tumors more rapidly compared with non-Tg mice. Malignant tumors were observed only in the carcinogen-treated Tg rasH2/CB6F1 mice, but not in non-Tg mice treated with the same carcinogens. Each carcinogen induced tumors in corresponding target tissues of the Tg rasH2/CB6F1 mice. Only a very few lung adenomas but no other tumors were seen as spontaneous tumors during the 6 months of carcinogenicity tests. These results demonstrate that more rapid onset and higher incidence of more malignant tumors can be expected with high probability after treatment with various genotoxic carcinogens in the Tg rasH2/CB6F1 mice than in control non-Tg mice. The Tg rasH2/CB6F1 mouse seems to be a promising candidate as an animal model for the development of a rapid carcinogenicity testing system.

Immunohistochemical overexpression of p16 protein associated with intact retinoblastoma protein expression in cervical cancer and cervical intraepithelial neoplasia

Both p16 and retinoblastoma (Rb) proteins are important tumor suppressors that regulate the cell cycle. The status of both proteins in invasive cervical cancer and cervical intraepithelial neoplasia (CIN) has not yet been examined. The aim of this study was to investigate the expression of p16 and Rb proteins by immunohistochemistry using 98 formalin-fixed and paraffin-embedded samples of various cervical neoplastic lesions. Strong immunoreactivity for the p16 protein was observed in both the nuclei and cytoplasm of all CIN and invasive cancer cases except several low-grade CIN lesions. Expression of Rb protein was also demonstrated in the scattered nuclei of neoplastic and normal cells in all cases investigated. The results suggest that the deletion or mutational inactivity of both p16 and Rb proteins may be a rare event in cervical carcinogenesis. Moreover, overexpression of the p16 protein may be a useful diagnostic marker for cervical neoplastic lesions on routine laboratory screening.

Ultrastructural study of gap junctions between dendrites of parvalbumin-containing GABAergic neurons in various neocortical areas of the adult rat

Parvalbumin (PV)-containing GABAergic neurons in the hippocampus form dual networks linked by both dendrodendritic gap junctions and mutual inhibitory synapses. Recent physiological studies have demonstrated similar functional connectivity among cortical GABAergic neurons, but the corresponding structures have not been fully analyzed at the electron microscopic level. In this study we examined detailed ultrastructural features of gap junctions between PV neurons in the mature neocortex. Light microscopic observations and confocal laser scanning microscopy revealed frequent dendrodendritic contacts between PV neurons. Electron microscopic analysis provided direct morphological evidence for the existence of gap junctions between 22 pairs of PV-immunoreactive dendrites in the visual, auditory, and somatosensory cortices. Their ultrastructural features that were characteristic of immunolabeled profiles were consistent with the general structure of gap junctions. In one case a gap junction coexisted with a dendrodendritic chemical synapse, making a mixed synapse. Importantly, we also encountered a gap junction between PV positive and negative, presumptive non-principal cell-derived, dendrites. Quantitative analysis was made in 16 pairs of PV positive dendrites forming gap junctions in the infragranular layers of the somatosensory cortex. Diameters of these dendrites ranged from 0.3 to 2.7 microm, suggesting diverse locations of gap junctions along the proximal-distal axis of dendritic trees, but the majority (81%) were less than 1 microm. The mean size of gap junctions along apposing membranes was 0.22+/-0.09 microm. By using this size, the theoretical value of a junctional conductance was estimated to be 2.1-5.3 nS. Dendrites of PV neurons in the infragranular layers of the somatosensory cortex were reconstructed light microscopically and the sites of contacts with other PV neurons were mapped. Although these contacts do not necessarily imply gap junctional coupling, their number (5.3+/-2.3 per cell, n=11) suggested the degree of connectivity of less than 10 coupling from single PV neurons with others. Sholl analysis revealed that only 38% of their dendrites occurred within 200 microm from the soma. The present study demonstrated detailed ultrastructural features of gap junctions between mature cortical PV neurons. These features will facilitate not only identification of gap junctions in variously labeled neurons but also analysis of their functional aspects by enabling theoretical estimate of their junctional conductances.

Mutations of a novel human RAD54 homologue, RAD54B, in primary cancer

Association of breast tumor susceptibility gene products BRCA1 and BRCA2 with the RAD51 recombination protein suggested that cancer could arise through defects in recombination. The identification of NBS1, responsible for Nijmegen breakage syndrome, from the MRE11/RAD50 recombination protein complex also supports this hypothesis. However, our mutation analysis revealed that known members of the RAD52 epistasis group are rarely mutated in human primary cancer. Here we describe the isolation of a novel member of the SNF2 superfamily, characterized with sequence motifs similar to those in DNA and RNA helicases. The gene, designated RAD54B, is significantly homologous to the RAD54 recombination gene. The expression of RAD54B was high in testis and spleen, which are active in meiotic and mitotic recombination. These findings suggest that RAD54B may play an active role in recombination processes in concert with other members of the RAD52 epistasis group. RAD54B maps to human chromosome 8q21.3-q22 in a region associated with cancer-related chromosomal abnormalities. Homozygous mutations at highly conserved positions of RAD54B were observed in human primary lymphoma and colon cancer. These findings suggest that some cancers arise through alterations of the RAD54B function.

Mitochondrial ubiquitin ligase MITOL ubiquitinates mutant SOD1 and attenuates mutant SOD1-induced reactive oxygen species generation

We have previously identified a novel mitochondrial ubiquitin ligase, MITOL, which is localized in the mitochondrial outer membrane and is involved in the control of mitochondrial dynamics. In this study, we examined whether MITOL eliminates misfolded proteins localized to mitochondria. Mutant superoxide dismutase1 (mSOD1), one of misfolded proteins, has been shown to localize in mitochondria and induce mitochondrial dysfunction, possibly involving in the onset and progression of amyotrophic lateral sclerosis. We found that in the mitochondria, MITOL interacted with and ubiquitinated mSOD1 but not wild-type SOD1. In vitro ubiquitination assay revealed that MITOL directly ubiquitinates mSOD1. Cycloheximide-chase assay in the Neuro2a cells indicated that MITOL overexpression promoted mSOD1 degradation and suppressed both the mitochondrial accumulation of mSOD1 and mSOD1-induced reactive oxygen species (ROS) generation. Conversely, the overexpression of MITOL CS mutant and MITOL knockdown by specific siRNAs resulted in increased accumulation of mSOD1 in mitochondria, which enhanced mSOD1-induced ROS generation and cell death. Thus, our findings indicate that MITOL plays a protective role against mitochondrial dysfunction caused by the mitochondrial accumulation of mSOD1 via the ubiquitin-proteasome pathway.