APC/C is essential for hematopoiesis and impaired in aplastic anemia.

Anaphase promoting complex/cyclosome (APC/C) is essential for cell cycle progression. Recently, its non-mitotic functions were also reported but less studied in several tissues including hematopoietic cells. Here, we developed an inducible Anapc2 (a core subunit of APC/C) knockout mice. The animals displayed a fatal bone marrow failure within 7 days after knockout induction. Their hematopoietic stem and progenitor cells (HSPCs) demonstrated a sharp decline and could form little colony. Further, the results of BrdU label-retaining cell assay showed that the dormant HPSCs lost rapidly. Analysis of cell cycle regulators, Skp2, P27, Cdk2, and Cyclin E1, suggested that these quiescent stem cells underwent a shift from quiescence to mitosis followed by apoptosis. We next detected Anapc2-expression in the CD34+ HSPCs of patients with aplastic anemia. CD34+ cells were markedly decreased in the bone marrow and Anapc2-expression in the residual CD34+ cells was undetectable, suggesting that APC/C was deficient and might have a relationship with the pathogenesis of aplastic anemia.

Renal tumor in developing countries: 142 cases from a single institution at Shanghai, China.

BACKGROUND: The clinical management of children with renal tumors including Wilms' tumor, clear cell sarcoma, rhabdoid tumor and other renal tumors in our center was designed according to the National Wilms' Tumor Study Group protocols. METHODS: A total of 142 consecutive patients who had been diagnosed as having renal tumors at Shanghai Children's Medical Center were reviewed retrospectively in the period of December 1998 and September 2012. Diagnosis and treatment were decided by a multidisciplinary team including oncologists, surgeons, pathologists and sub-specialized radiologists. RESULTS: The median age of the patients at the time of diagnosis was 27 months. The tumor stages of the patients were as follows: stage I 24.6%, stage II 23.2%, stage III 32.3%, stage IV 14.1%, and stage V 5.6%. Favorable histology was diagnosed in 80.3%, anaplasia in 4.2%, clear cell sarcoma in 9.8%, rhabdoid tumor in 4.9%, and other renal tumors in 0.7% of the patients. The event-free and overall 5-year survival rates were 80% and 83%, respectively. Tumor relapse and progress was seen in 25 patients (17.6%). The median relapse time was 6 months (range: 2-37 months). Seven relapsing patients were retreated and four of them got second complete remission (three in stage II, one in stage I). CONCLUSION: A multi-disciplinary team work model is feasible in developing countries, and the renal tumors protocols basically from developed countries are safe in developing countries.

Leukemia propagating cells rebuild an evolving niche in response to therapy.

Residence of cancer-propagating cells (CPCs) within preferential microenvironmental niches has a major part in evading therapy. However, the nature of niches involved and the mechanisms protecting CPCs remain largely unknown. We addressed these issues in mouse transplantation models of acute lymphoblastic leukemia (ALL). When the engrafted leukemic cells substantially damaged adjacent microenvironment in the bone marrow (BM), after chemotherapy small foci of CPCs were retained, surrounded by sheaths of supporting cells that comprise a protective niche. We investigated patients' BM biopsies and found evidence of a similar process in patients receiving induction therapy. The efficacy of chemotherapy was enhanced by interfering with the niche formation or function. We therefore identified a therapy-induced niche that protects CPCs.

Immunohistochemical detection of uPA, PAI-1, and alpha-SMA in aneurysms of patients with perimembranous ventricular septal defect.

BACKGROUND AND AIM OF THE STUDY: A perimembranous ventricular septal defect (PMVSD) may be partially or completely occluded by aneurysms that originate from the tricuspid valve leaflets, though the exact mechanisms of closure remain unknown. It is hypothesized that valvar interstitial cells (VICs) mediate extracellular matrix (ECM) remodeling in aneurysms via the secretion of a serine proteinase and its inhibitor. METHODS: The functional characteristics of VICs in 15 aneurysms and in four normal tricuspid valve leaflets obtained at autopsy were evaluated by detecting the expression of urokinase plasminogen activator (uPA), plasminogen activator inhibitor-1 (PAI-1), and alpha-smooth muscle actin (alpha-SMA) in the specimens, using immunohistochemical methods. RESULTS: uPA and alpha-SMA were recognized predominantly in VICs located mainly in regions adjacent to the endothelium and smooth muscle cells of blood vessels. PAI-1 was identified in VICs found mainly in granulation tissues, and in endothelial cells. Two types of granulation tissue (myxoid and fibrous tissue) were associated with aneurysms. Nine aneurysms expressed a high uPA activity and a low PAI-1 activity (uPA/PAI-1 ratio 1.78), while six aneurysms expressed a low uPA activity and a high PAI-1 activity (uPA/PAI-1 ratio 0.14). CONCLUSION: The expression of uPA, PAI-1 and alpha-SMA in VICs suggests that interactions among these molecules contribute to ECM remodeling during aneurysm formation and development. This provides a potential mechanism for defect closure in patients with PMVSD.

[Atypical teratoid/rhabdoid tumors of central nervous system in childhood: a clinical and histopathologic study of 6 cases].

OBJECTIVE: To study the clinicopathologic features, immunohistochemical findings, diagnosis and differential diagnosis of atypical teratoid/rhabdoid tumors (AT/RT) of central nervous system in childhood. METHODS: The clinicopathologic data, morphologic features and immunophenotypes were reviewed in 6 cases of AT/RT. EnVision method was applied. Antibodies include cytokeratin (CK), epithelial membrane antigen (EMA), vimentin, smooth muscle actin (SMA), muscle specific actin (MSA), glial fibrinary acid protein (GFAP), desmin, placental alkaline phosphatase (PLAP) and INI1. RESULTS: Five of the six cases of AT/RT occurred in infancy and early childhood. Histologically, the predominant component was rhabdoid cells. Cytoplasmic inclusions were present in all cases. Primitive neuroectodermal tumor (PNET) component was also identified in 5 of the 6 cases studied. Immunohistochemically, the tumor cells were positive for cytokeratin, epithelial membrane antigen and vimentin. The staining for INI1, desmin and PLAP was negative. Smooth muscle actin was expressed in 2 cases and glial fibrillary acidic protein in 5 cases. The proliferative index as demonstrated by Ki-67 staining was high. CONCLUSIONS: AT/RT is not a particularly uncommon malignancy in childhood. The histologic hallmark is the presence of rhabdoid cells with cytoplasmic inclusions. The tumor cells are positive for cytokeratin, epithelial membrane antigen and vimentin, and negative for INI1. Differential diagnosis includes PNET, medulloblastoma and medullomyoblastoma.

Ectopic expression of retinoic acid receptors and change of myocardial structure in the offspring heart with vitamin A deficiency.

Vitamin A is a key micronutrient required during crucial stages of embryonic development and vitamin A deficiency (VAD) results in embryonic heart malformation. The pleiotropic functions of vitamin A are mediated by specific nuclear receptors: the retinoic acid receptors (RARα, -ß, and -γ) and the retinoic X receptors (RXRα, -ß, and -γ). The action of nuclear receptors has been implicated in controlling of cell proliferation, differentiation and apoptosis, and the expressions of these receptor genes are regulated by retinoic acid levels during the early stages of embryonic development. GATA-4 is one of the earliest transcription factors expressed in developing cardiac cells. However, the functional links of specific nuclear receptors to heart development in VAD embryos are not clearly understood. In our study, weaning female Sprague-Dawley rats were fed a modified diet containing different concentrations of vitamin A according to the American Institute of Nutrition 93 Growth Purified Diet. After 10-wk feeding, the female rats were mated with normal male rats, and a portion of them were transferred to a diet with enough added vitamin A for the pregnancy cycle. The embryo hearts were dissected out at embryonic day 13.5 (E13.5) to study the expression of RARs, RXRs and GATA-4. The embryo hearts from E18.5 were for observation of ultrastructural changes. In comparison to vitamin A supplemented groups, the embryo hearts from vitamin A insufficient groups exhibited ultrastructural changes and significantly lower expression of GATA-4, RARα, and -γ, and higher expression of RXRα and -ß. Our findings suggest that the down-regulation of RARs and the up-regulation of RXRs resulted from VAD affected GATA-4 gene expression, which resulted in ultrastructural changes in embryo hearts due to maternal insufficiency of vitamin A during pregnancy.

[Correlation between typing of peripheral neuroblastic tumors and prognosis: a clinicopathologic study of 135 cases].

OBJECTIVE: To study the clinicopathologic characteristics of peripheral neuroblastic tumors and to investigate the prognostic significance of International Neuroblastoma Pathology Classification (INPC). METHODS: One hundred and thirty-five cases of peripheral neuroblastic tumors encountered in Shanghai Children's Medical Center were enrolled into the study. All the cases were classified according to INPC and International Neuroblastoma Staging System (INSS). The follow-up data were analyzed. RESULTS: The consensus diagnoses of the 135 cases were as follows: 80 cases (59.2%) of neuroblastoma, 24 cases (17.8%) of ganglioneuroblastoma, intermixed, 17 cases (12.6%) of ganglioneuroma and 14 cases (10.4%) of ganglioneuroblastoma, nodular. The cases were subdivided into 2 subgroups: favorable histology (number = 90, 66.7%) and unfavorable histology (number = 45, 33.3%). According to INSS, the number of cases in stages I, II, III and IV was 22 (16.3%), 24 (17.8%), 34 (25.2%) and 55 (40.7%), respectively. The survival of peripheral neuroblastic tumors correlated with histologic diagnosis, INPC and INSS (P < 0.05). CONCLUSION: Diagnostic categorization of peripheral neuroblastic tumors according to INPC is of prognostic value.

Glial fibrillary acidic protein expression is an indicator of teratoma maturation in children.

BACKGROUND: The present diagnosis of teratomas is limited to visual examination of their tissues. For the sake of treatment, teratomas are graded according to degrees of nerve tissue maturation. Mature fetal nerve tissue contains the astrocyte-specific intermediate filament protein, the glial fibrillary acidic protein (GFAP). This study aimed to investigate GFAP expressions in the nerve tissue of immature and mature teratomas, and to evaluate if GFAP is indicative of teratoma maturation in pediatric patients. METHODS: Nerve tissue specimens were collected from immature (10 children) and mature teratomas (45 children). Nerve tissue specimens as a control group were taken from 33 children with neuroblastoma. GFAP expression of the specimens was studied by immunohistochemical and semi-quantitative analyses. RESULTS: GFAP expression was low in the nerve tissue of immature teratomas and high in that of mature ones. A semi-quantitative analysis confirmed statistically significant difference between the GFAP expressions of immature and mature teratomas (P=0.0001). CONCLUSION: GFAP is highly expressed in the nerve tissue of mature teratomas and low in that of immature ones, suggesting that the GFAP expression is a meaningful indicator of teratoma maturation. It is helpful for pathologists to diagnose and classify teratomas.

The cultivation and identification of tumor stem cells from neuroblastoma derived tumor spheres.

BACKGROUND AND OBJECTIVE: Since the proposal of the tumor stem cell hypothesis, considerable interest has been devoted to the isolation and purification of tumor stem cells. Tumor stem cell enrichment from primary tumor derived cell spheres has been demonstrated in specific, serum-free media. This goal of this study is to establish a method of cultivating floating tumor spheres from neuroblastoma cells and to confirm that neuroblastoma spheres are rich in tumor stem cells. METHODS: Bone marrow aspirates were obtained from pediatric patients diagnosed with stage IV neuroblastoma. Primary tumor cells were isolated and cultivated in serum-free, stem cell-selective medium. Single sphere-forming cells were cultivated under serum-free conditions; their cloning efficiency and monoclonal tumor sphere formation rates were calculated. The expression of stem cell marker genes Oct-4 and Bmi-1 was detected by RT-PCR in sphere-forming cells and parental neurolastoma cells. Sphere-forming cells were injected into the armpit of nude mice with subsequent assessment for tumor growth. Sphere-forming cells were cultivated in differentiation medium containing 5 µmol/L 13-cis retinoic acid; changes in cell morphology were observed. RESULTS: Neuroblastoma cells formed non-adherent neurospheres under serum-free, stem cell-selective conditions after a period of 4 to 6 days. A single cell dissociated from a neurosphere could reform a monoclonal sphere; cloning efficiency and monoclonal sphere formation rates were 55.3% and 26.3%, respectively. RT-PCR results revealed heightened tumor sphere expression of Oct-4 and Bmi-1 as compared with parental tumor cells. Fourteen days after injection of 10(4) sphere-forming cells into nude mice, a neuroblastoma xenograft formed. Treatment of sphere-forming cells with 13-cis retinoic acid induced a gradual differentiation to neuronal cell morphology. CONCLUSIONS: Neuroblastoma derived tumor spheres enrich tumor stem cells and the cultivation of primary neuroblastoma cells in serum-free, stem cell-selective medium is an effective method to dissociate and purify tumor stem cells in vitro.

Use of foetal MRI in diagnosing hepatic hemangioendotheliomas: a report of four cases.

OBJECTIVE: To examine the appearance of foetal hepatic hemangioendotheliomas using prenatal magnetic resonance imaging (MRI) and to conclude whether MRI provides additional information to that obtained with ultrasonography (US). MATERIALS AND METHODS: Four foetuses with hepatic hemangioendotheliomas were evaluated by US and MRI between 2005 and 2008. MRI was performed on four foetuses at 33+4, 37+4, 24 and 21+6 weeks gestation following US evaluations that demonstrated foetal abdominal tumours. The prenatal US and MRI findings were compared with the postnatal physical examination, enhancement computed tomography (CT) and serial ultrasound examinations, or with the pathology exams, retrospectively. RESULTS: All four foetuses showed very similar prenatal MRI findings. In each case, the foetal MRI detected an isolated vascular hepatic tumour with low T1 and inhomogeneous high T2 signal intensity. In one case, multiple scalp hemangiomas were detected in the postnatal physical examination, but not with the prenatal US and MRI exams. In the other three cases, the prenatal US and MRI findings were in complete agreement with the postnatal diagnoses. CONCLUSION: Prenatal MRI is effective in the assessment of foetal hepatic hemangioendotheliomas. Prenatal MRI may provide a useful adjunct to US in assessing foetal hepatic tumours.

Combined fontanelle puncture and surgical operation in treatment of desmoplastic infantile astrocytoma: case report and a review of the literature.

Desmoplastic infantile astrocytoma is a rare low-grade malignant brain tumor found in infants. Its pathological diagnosis can be made on the basis of its histological characteristics and immunohistochemical staining. A case of desmoplastic infantile astrocytoma, including its clinical manifestations, pathological characteristics, differential diagnosis, treatment, and prognosis, is reported. Presurgical percutaneous decompression and subsequent resection resulted in a satisfactory therapeutic outcome.

Leydig cell transplantation restores androgen production in surgically castrated prepubertal rats.

Prepubertal testicular dysfunction and the subsequent development of hypogonadism affects an estimated one in 200 children worldwide. As the testosterone levels are dynamic during development and puberty, traditional hormone treatment regimens are often inadequate, thereby leaving associated physiological conditions unresolved. Therefore, we have investigated the potential therapeutic effect of mature Leydig cell transplantation for the treatment of prepubertal primary hypogonadism through the use of a surgically induced hypogonadistic rat model system. In the experiment, Leydig cells were surgically isolated from mature Sprague-Dawley rats and transplanted into prepubertal recipients. Serum testosterone levels and microscopic analysis of the stained testicular interstitium were compared with sham-treated controls, as well as with castrated and intact rats during sexual development. At 4 weeks post-implantation, serum testosterone was detectable in Leydig cell recipients, but not in surgical controls, and progressively increased as a function of time until reaching levels comparable with sexually mature males at 12 weeks post-implantation. Histological analysis revealed a high rate of Leydig cell survival as well as steroidogenic secretory activity. Therefore, we conclude that mature Leydig cell transplantation in prepubertal hypogonadism recipients has therapeutic potential in rats and merits further investigation for clinical application.

[Relationship between the types of Helicobacter pylori strains and chronic upper gastrointestinal diseases in children].

OBJECTIVE: To study the relationship of the types of Helicobacter pylori (H. pylori) strains with the classification and the severity of chronic gastro-duodenal diseases in children. METHODS: One hundred and fifteen children with chronic upper gastrointestinal symptoms who were diagnosed as H. pylori infection by gastroscopy were enrolled in this study. H. pylori strains were serotyped by immunoblot technique. The gastric biopsy specimens of all patients were studied histologically. RESULTS: Type I H. pylori strains were confirmed in 84 cases (73.0%), intermediate type strains in 21 cases (18.3%), and type II strains in 10 cases (8.7%). Type I H. pylori strains infection caused a moderate gastric mucosal inflammation in 83 cases and a severe inflammation in 1 case. Intermediate type H. pylori strains infection caused a moderate gastric mucosal inflammation in 21 cases. Type II H. pylori strains infection caused a mild gastric mucosal inflammation in 2 cases and a moderate inflammation in 8 cases. Different types of H. pylori strains resulted in different severity of gastric mucosal inflammation (x2=15.444, P < 0.01). The gastric mucosal inflammation due to type I H. pylori strains was the most severe, while the inflammation due to type II H. pylori strains was relatively mild. The incidence of nodulus lymphaticus of gastric mucosa due to type I, type II and intermediate type H. pylori strains infection was 76.2%, 47.6% and 40.0%, respectively (x2=10.171, P < 0.01). The classification of chronic gastro-duodenal diseases was not associated with the types of H. pylori strains. CONCLUSIONS: Type I strains were the leading cause of H. pylori infection in children. All of types of H. pylori strains can cause pathohistologic changes of gastric mucosa. Type I H. pylori strains infection can result in the most severe gastric mucosal inflammation and the highest incidence of nodulus lymphaticus. The immunoblot serotyping of H.pylori strains may be useless for the classification of chronic upper gastrointestinal diseases but it is helpful for the evaluation of the severity of the diseases in children.

[Unusual expression and molecular mechanisms of E-cadherin, beta-catenin in correlation with clinicopathologic parameters in neuroblastoma].

OBJECTIVE: To study the expression of E-cadherin and beta-catenin in neuroblastomas of various degrees of differentiation, and to investigate their molecular mechanisms in correlation with clinicopathologic parameters. METHODS: Immunohistochemistry EnVision method was used to detect E-cadherin and beta-catenin expression in 90 paraffin-embedded tissue samples of neuroblastomas. The methylation status of CpG islands of E-cadherin promoter was investigated by MSP in 7 fresh tissue and 24 paraffin-embedded tissue samples. The mutation status of exon 3 of beta-catenin gene was studied by PCR in 7 fresh tissue samples. Statistical analysis of the data was performed by SPSS software. RESULTS: E-cadherin and beta-catenin were abnormally expressed in neuroblastomas in general. The expression of beta-catenin in well-differentiated neuroblastoms was markedly higher (47/70, 67.1%) than that of the poorly differentiated tumors (8/20, 40.0%). There was a markedly decreased expression of both genes in tumors with lymph node metastasis than those without. Demethylation was seen in some regions of the promoter of E-cadherin in 31 cases of nuroblatomas. PCR of the exon 3 of beta-catenin followed by DNA sequencing demonstrated rearrangements and mutations in 7 cases, including 2 cases harboring identical point mutation at gene position 27184, leading to a T-->A alteration. CONCLUSIONS: The abnormal over-expression of E-cadherin in neuroblastomas is independent of the methylation status of their promoter sequences. The abnormal expression of beta-catenin may be related to mutational changes at exon 3 of the gene.

[Metanephric stromal tumor: a pathologic study of two cases].

OBJECTIVE: To study the clinicopathologic features of metanephric stromal tumor (MST), with emphasis on diagnostic criteria. METHODS: The clinicopathologic findings in 2 cases of MST were analyzed and the literature of this entity was reviewed. RESULTS: Cases of MST were unilateral and mostly centered in renal medulla. The tumor was separated from adjacent renal tissue by sharp and scalloped borders. Entrapped tubules and glomeruli were commonly seen within the lesion. The tumor cells were spindle to stellate in shape and arranged in a nodular pattern. On low power examination, alternating areas of high and low tumor cellularity were noted. Characteristically, there were onion skin-like concentric cuffs of tumor cells around entrapped tubules. The small intratumoral vasculatures showed irregular thickening ("angiodysplasia"). Immunohistochemical study demonstrated that the tumor cells diffusely expressed CD34. CONCLUSIONS: Which the tumor cells around the entrapped renal tubules and blood vessels imparts a nodular appearance, as well as the tumor cells labbed for CD34 are the highly characteristic pathologic findings of MST.