cAAVe phaenomena: Beware of appearances!

In this issue of Cell, Wang et al. come to the unsettling conclusion that adeno-associated viruses, despite being engineered for glia-specific expression, can become widely active in endogenous neurons, misleading researchers in their quest for efficient conversion of glia into neurons for brain repair.

Direct In Vitro Reprogramming of Astrocytes into Induced Neurons.

Spontaneous neuronal replacement is almost absent in the postnatal mammalian nervous system. However, several studies have shown that both early postnatal and adult astroglia can be reprogrammed in vitro or in vivo by forced expression of proneural transcription factors, such as Neurogenin-2 or Achaete-scute homolog 1 (Ascl1), to acquire a neuronal fate. The reprogramming process stably induces properties such as distinctly neuronal morphology, expression of neuron-specific proteins, and the gain of mature neuronal functional features. Direct conversion of astroglia into neurons thus possesses potential as a basis for cell-based strategies against neurological diseases. In this chapter, we describe a well-established protocol used for direct reprogramming of postnatal cortical astrocytes into functional neurons in vitro and discuss available tools and approaches to dissect molecular and cell biological mechanisms underlying the reprogramming process.

Increasing Neural Stem Cell Division Asymmetry and Quiescence Are Predicted to Contribute to the Age-Related Decline in Neurogenesis.

Adult murine neural stem cells (NSCs) generate neurons in drastically declining numbers with age. How cellular dynamics sustain neurogenesis and how alterations with age may result in this decline are unresolved issues. We therefore clonally traced NSC lineages using confetti reporters in young and middle-aged adult mice. To understand the underlying mechanisms, we derived mathematical models that explain observed clonal cell type abundances. The best models consistently show self-renewal of transit-amplifying progenitors and rapid neuroblast cell cycle exit. In middle-aged mice, we identified an increased probability of asymmetric stem cell divisions at the expense of symmetric differentiation, accompanied by an extended persistence of quiescence between activation phases. Our model explains existing longitudinal population data and identifies particular cellular properties underlying adult NSC homeostasis and the aging of this stem cell compartment.

Fast clonal expansion and limited neural stem cell self-renewal in the adult subependymal zone.

We analyzed the progeny of individual neural stem cells (NSCs) of the mouse adult subependymal zone (SEZ) in vivo and found a markedly fast lineage amplification, as well as limited NSC self-renewal and exhaustion in a few weeks. We further unraveled the mechanisms of neuronal subtype generation, finding that a higher proportion of NSCs were dedicated to generate deep granule cells in the olfactory bulb and that larger clones were produced by these NSCs.

Preoperative multidetector-row computed tomography scan staging for lymphatic gastric cancer spread.

BACKGROUND: Multidetector-row computed tomography (MDCT) is commonly used to stage patients with gastric cancer, even though the technique often shows low specificity for lymph-node involvement. METHODS: In this study, 111 patients with gastric cancer who consecutively underwent MDCT scan followed by radical surgical treatment at our hospital were retrospectively evaluated. RESULTS: In total, 3632 lymph nodes from 643 lymphatic stations were studied and then correlated with radiological features. Lymph-node size was not always associated with infiltration. Of the 261 lymph-node stations that were not radiologically detected, 60 (22.9%) were infiltrated. There were 108 stations with lymph nodes larger than 10 mm seen on MDCT, of which 67 (62%) had lymphatic invasion. The sensitivity was 32.6%, specificity 90.6%, positive predictive value 62.0%, negative predictive value 74.2%, and accuracy 72.1%. When three lymph nodes, at least one of which was larger than 10 mm, were detected in the same station, infiltration was confirmed with 99% specificity in 93.8% of patients. Moreover, all of the 13 patients in whom three lymph nodes larger than 10 mm were detected in different neighboring stations had lymphatic invasion. CONCLUSIONS: Although presence of lymph nodes greater than 10 mm in size is not, in itself, sufficient to confirm lymphatic invasion, nodal involvement can be hypothesized when associated images are detected by MDCT.

Cystosarcoma phyllodes with muscular and lymph node metastasis. Our experience and review of the literature.

BACKGROUND: Phyllodes tumors are biphasic fibroepithelial neoplasms of the breast. While the surgical management of these relatively uncommon tumors has been addressed in the literature, few reports have commented on the surgical approach to tumors greater than ten centimeters in diameter - the giant phyllodes tumor. CASE REPORT: We report a case of a 45-year-old woman who presented with a large lump in her right breast, involvement of multiple ipsilateral axillary lymph nodes and pectoralis major muscle. Clinical findings and cytologic examination (fine-needle aspiration) were suggestive of cystosarcoma phyllodes and we discuss the techniques utilized for pre-operative diagnosis, tumor removal, and breast reconstruction. A review of the literature on the surgical management of phyllodes tumors was performed. CONCLUSION: Management of the phyllodes tumor presents the surgeon with unique challenges. The majority of these tumors can be managed by simple mastectomy. In our case clinical findings and cytologic examination (fine-needle aspiration) were suggestive of cystosarcoma phyllodes, for which the patient underwent a modified radical mastectomy. Postoperative radio therapy was given to the loco regional area. KEYWORDS: Immediate reconstruction, Phylloides tumors, Post-operative radio therapy, Radical surgery.

Antagonistic modulation of gliomagenesis by Pax6 and Olig2 in PDGF-induced oligodendroglioma.

Gliomas are aggressive tumors of the central nervous system originating from proliferating neural cells. Regulators of neural stem or progenitor cells biology may thus influence aspects of brain tumorigenesis, such as the maintenance of tumor-propagating potential. We investigated the role of Pax6, a neurogenic transcription factor already suggested as a positive prognostic marker for human gliomas, in a well-characterized in vivo model of PDGF-B-driven oligodendroglioma. In this system, the expression of Pax6 severely impairs tumor propagation by inducing a reduction of cell proliferation and the acquisition of differentiation traits in tumor-initiating cells. The overexpression of Pax6 correlates with a downregulation of Olig2, a bHLH transcription factor that normally antagonizes Pax6 in adult neurogenic niches and that plays a key role in the maintenance of neural stem and progenitor cells. Furthermore, we found that Olig2 is strictly required to maintain the malignancy of oligodendroglioma cells, since its silencing by interfering RNA abrogates tumor propagation. We finally show evidence that this function depends, at least in part, on the silencing of ID4, a dominant negative bHLH protein, whose upregulation follows Olig2 loss. In our model, the upregulation of ID4 mimics the loss of Olig2 in impairing the tumor-propagating potential of glioma cells. Our data, therefore, establish the relevance of physiological regulators of neural stem cell biology in regulating glial tumor malignancy and provide support for their functional interactions in this context.

Does mediastinal extension of the goiter increase morbidity of total thyroidectomy? A multicenter study of 19,662 patients.

PURPOSE: To compare the outcome in patients with cervical goiters and cervicomediastinal goiters (CMGs) undergoing total thyroidectomy using the cervical or extracervical approach. METHODS: This was a retrospective study conducted at six academic departments of general surgery and one endocrine-surgical unit in Italy. The study population consisted of 19,662 patients undergoing total thyroidectomy between 1999 and 2008, of whom 18,607 had cervical goiter (group A) and 1055 had CMG treated using a cervical approach (group B, n = 986) or manubriotomy (group C, n = 69). The main parameters of interest were symptoms, gender, age, operative time, duration of drain, length of hospital stay, malignancy and outcome. RESULTS: A split-sternal approach was required in 6.5% of cases of CMG. Malignancy was significantly more frequent in group B (22.4%) and group C (36.2%) versus group A (10.4%; both P < .001), and in group C versus group B (P = .009). Overall morbidity was significantly higher in groups B + C (35%), B (34.4%) and C (53.5%) versus group A (23.7%; P < .001). Statistically significant increases for group B + C versus group A were observed for transient hypocalcemia, permanent hypocalcemia, transient recurrent laryngeal nerve (RLN) palsies, permanent RLN palsies, phrenic nerve palsy, seroma/hematoma, and complications classified as other. With the exception of transient bilateral RLN palsy, all of these significant differences between group B + C versus group A were also observed for group B versus group A. CONCLUSIONS: Symptoms, malignancy, overall morbidity, hypoparathyroidism, RLN palsy and hematoma are increased in cases of substernal goiter.

PDGF-B-driven gliomagenesis can occur in the absence of the proteoglycan NG2.

BACKGROUND: In the last years, the transmembrane proteoglycan NG2 has gained interest as a therapeutic target for the treatment of diverse tumor types, including gliomas, because increases of its expression correlate with dismal prognosis. NG2 has been shown to function as a co-receptor for PDGF ligands whose aberrant expression is common in gliomas. We have recently generated a glioma model based on the overexpression of PDGF-B in neural progenitors and here we investigated the possible relevance of NG2 during PDGF-driven gliomagenesis. METHODS: The survival curves of NG2-KO mice overexpressing PDGF-B were compared to controls by using a Log-rank test. The characteristics of tumors induced in NG2-KO were compared to those of tumors induced in wild type mice by immunostaining for different cell lineage markers and by transplantation assays in adult mice. RESULTS: We showed that the lack of NG2 does not appreciably affect any of the characterized steps of PDGF-driven brain tumorigenesis, such as oligodendrocyte progenitor cells (OPC) induction, the recruitment of bystander OPCs and the progression to full malignancy, which take place as in wild type animals. CONCLUSIONS: Our analysis, using both NG2-KO mice and a miRNA based silencing approach, clearly demonstrates that NG2 is not required for PDGF-B to efficiently induce and maintain gliomas from neural progenitors. On the basis of the data obtained, we therefore suggest that the role of NG2 as a target molecule for glioma treatment should be carefully reconsidered.

Recent insights into PDGF-induced gliomagenesis.

Gliomas are aggressive and almost incurable glial brain tumors which frequently display abnormal platelet-derived growth factor (PDGF) signaling. Evidence gained from studies on several in vivo animal models has firmly established a causal connection between aberrant PDGF signaling and the formation of some gliomas. However, only recently has significant knowledge been gained regarding crucial issues such as the glioma cell of origin and the relationship between the transforming stimulus and the cellular characteristics of the resulting tumor. Based on recent evidence, we propose that PDGF can bias cell-fate decisions, driving the acquisition of cell type-specific features by the progeny of multipotent neural progenitors, thus determining the shape and direction of the transformation path. Furthermore, recent data about the cellular mechanisms of PDGF-driven glioma progression and maintenance indicate that PDGF may be required, unexpectedly, to override cell contact inhibition and promote glioma cell infiltration rather than to stimulate cell proliferation.

Persistent hypercalcitoninemia in patients with medullary thyroid cancer.

Medullary thyroid carcinoma is a highly malignant and progressive disease. Surgery is the only effective treatment. Calcitonin is a significant marker for medullary thyroid carcinoma, and due to its sensitivity it represents a useful tool for the follow-up. The outcome of patients affected by medullary thyroid carcinoma depends on tumor size, lymph node involvement, and adequacy of primary surgical management. In the present study, the authors reviewed their own experience in the cure of medullary thyroid carcinoma. Forty-one patients operated for sporadic medullary thyroid carcinoma were included. Indications for surgery, inclusive of lymphectomy techniques, timing of redo surgery, and the meaning of calcitonin levels in highlighting disease are extensively discussed. Patients with elevated calcitonin levels and favorable outcome are considered, together with the various diagnostic tools to be employed during patient workup.

Multidisciplinary approach to the treatment of bone metastases: Osteo-Oncology Center, a new organizational model.

AIMS AND BACKGROUND: Bone metastases are responsible for high morbidity in cancer patients. The frequency of pain and other serious complications associated with such metastases depends on the site and type of lesions and preventive therapy. The present paper aims to inform the scientific community about a new organizational health care model specifically designed for patients with bone metastases, in the hope of stimulating the creation of similar initiatives whose goals are to decrease the high morbidity of this pathology, reduce the frequency of complications, limit psychophysical distress of patients, and improve quality of life. METHODS: In January 2005, an Osteo-Oncology Center was opened in our institute to provide multidisciplinary care (19 specialists involved) for patients with bone metastases, to train physicians, and to conduct research in the field. RESULTS: In its first three years of activity, 601 multidisciplinary team consultations were made and a total of 425 patients were seen. The most frequent primary tumor site was the lung in males and the breast in females. Upon presentation at the Center, 79% of patients reported experiencing a level of pain (median pain intensity, 3.69) that interfered with normal daily activities. An anonymous questionnaire was also completed on the quality of the service provided: 75% of patients were very satisfied, 23% were satisfied, 1% responded "I don't know", and only 1% expressed dissatisfaction. CONCLUSIONS: Our preliminary results confirm the usefulness of a multidisciplinary center for the management of patients with bone metastases, especially in terms of decreasing psychophysical suffering.

PDGF-B induces a homogeneous class of oligodendrogliomas from embryonic neural progenitors.

We describe the generation of mouse gliomas following the overexpression of PDGF-B in embryonic neural progenitors. Our histopathological, immunohistochemical and genome-wide expression analyses revealed a surprising uniformity among PDGF-B induced tumors, despite they were generated by transducing a highly heterogeneous population of progenitor cells known for their ability to produce all the cell types of the central nervous system. Comparison of our microarray data with published gene expression data sets for many different murine neural cell types revealed a closest correlation between our tumor cells and oligodendrocyte progenitor cells, confirming definitively that PDGF-B-induced gliomas are pure oligodendrogliomas. Importantly, we show that this uniformity is likely due to the ability of PDGF-B overexpression to respecify competent embryonic neural precursors toward the oligodendroglial lineage, providing evidence that the transforming activity of PDGF-B is influenced by the developmental potential of the targeted cells. Interestingly, we found that PDGF-B-induced tumors harbor different proliferating cell populations. However only PDGF-B-overexpressing cells are tumorigenic, indicating that paracrine signaling from the tumor is unable to transform bystander cells.

Tumor progression and oncogene addiction in a PDGF-B-induced model of gliomagenesis.

Platelet-derived growth factor B (PDGF-B) overexpression induces gliomas of different grades from murine embryonic neural progenitors. For the first time, we formally demonstrated that PDGF-B-induced neoplasms undergo progression from nontumorigenic low-grade tumors toward highly malignant forms. This result, showing that PDGF-B signaling alone is insufficient to confer malignancy to cells, entails the requirement for further molecular lesions in this process. Our results indicate that one of these lesions is represented by the down-regulation of the oncosuppressor Btg2. By in vivo transplantation assays, we further demonstrate that fully progressed tumors are PDGF-B-addicted because their tumor-propagating ability is lost when the PDGF-B transgene is silenced, whereas it is promptly reacquired after its reactivation. We provide evidence that this oncogene addiction is not caused by the need for PDGF-B as a mitogen but, rather, to the fact that PDGF-B is required to overcome cell-cell contact inhibition and to confer in vivo infiltrating potential on tumor cells.

Surgical treatment of intrathyroid metastases: preliminary results of a multicentric study.

BACKGROUND: Intrathyroid metastases (ITM) are rare and usually have a dismal prognosis. The aim of this study was to detect which neoplasms metastasize most often to the thyroid gland, their clinical features and treatment options. MATERIALS AND METHODS: Retrospective analysis of clinical files of 17,122 patients submitted to surgery for thyroid disease between 1995 and 2005. Twenty-five patients (median age 61 years) were affected by ITM. RESULTS: The site of the primary tumor was: kidney (15), lung (4), colon (3), breast (1), melanoma (1), and unknown in 1 patient. Ten patients (40%) complained of preoperative symptoms, in the others, thyroid involvement was incidentally discovered during the follow-up for the primary cancer. Twenty patients (80%) underwent total thyroidectomy, 3 received thyroid lobectomy and 2 palliative procedures. Morbidity was 16%, mortality was nil. The median follow-up was 24 months. CONCLUSION: ITM should always be suspected in any patient with a previous history of malignancy. Fine-needle agobiopsy (FNAB) with immunohistochemical stains may help in preoperative workup. A long delay between the primary tumor and the recurrence warrants surgery and total thyroidectomy seems to be the treatment of choice because of the multifocality of metastasis to the thyroid gland.

[Molecular medicine in thyroid surgery]. / Medicina molecolare in chirurgia della tiroide.

Cancer originates from a single cell which, through the acquisition of mutations in genes for key growth and survival factors, undergoes clonal expansion. Study of the genome allowed the detection of genes whose mutation is involved in tumour formation. In detail, in most thyroid neoplasms we are now able to identify the genes which cause cancer initiation. Moreover, correlations between mutations and clinico-pathological features of the tumours have been revealed. Thus, the genetic study of tumours is not anymore only a scientific curiosity, but a useful tool for the formulation of the more efficacious therapeutic and follow-up strategies. In this review we will summarize the more recent molecular medicine acquisitions in the thyroid cancer field and will describe their present and eventually future impact on the activity of the endocrine surgeon.

[Non-recurrent inferior laryngeal nerves and sympathetic-inferior laryngeal anastomotic branches: 6 years' personal experience]. / Il nervo laringeo inferiore non ricorrente e le anastomosi con il simpatico cervicale. La nostra esperienza di 6 anni.

The incidence and possible association of inferior laryngeal nerve and sympathetic anastomotic branch anomalies were evaluated in this study. Non-recurrent inferior laryngeal nerves stem from vascular anomalies involving the right subclavian artery and aortic arches during embryological development. These anomalies usually have no functional consequences (except for occasional dysphagia), but are potentially dangerous during thyroid surgery, occurring in about 1% of cases. Sympathetic-inferior laryngeal anastomotic branches are described in about 1.5% of cases, and may be confused with non-recurrent inferior laryngeal nerves. 1473 patients submitted to total thyroidectomy for benign disease over the period 2001-2006 were evaluated. Four non-recurrent inferior laryngeal nerves (incidence: 0.27%) and 11 sympathetic-inferior laryingeal anastomotic branches (incidence: 0.74%) were observed. Out of a total of 25 definitive inferior laryngeal nerve lesions, 1 occurred in a case of non-recurrent inferior laryngeal nerve. Awareness of the anatomical anomalies described and accurate surgical technique, including a constant search for the inferior laryngeal nerve, are the requirements for identification of non-recurrent inferior laryngeal nerves and sympathetic-inferior laryngeal anastomotic branches. During the pre-operative workup, ultrasonographic study of the right subclavian artery may be advisable in order to rule out alterations of its origin and course.

The ACTIVE (Acute Cholecystitis Trial Invasive Versus Endoscopic) study: multicenter randomized, double-blind, controlled trial of laparoscopic (LC) versus open (LTC) surgery for acute cholecystitis (AC) in adults.

BACKGROUND: In some randomized trials successful laparoscopic cholecystectomy for cholecystitis is associated with an earlier recovery and shorter hospital stay when compared with open cholecystectomy. Other studies did not confirm these results and showed that the potential advantages of laparoscopic cholecystectomy for cholecystitis can be offset by a high conversion rate to open surgery. Moreover in these studies a similar postoperative programme to optimize recovery comparing laparoscopic and open approaches was not standardized. These studies also do not report all eligible patients and are not double blinded. DESIGN: The present study project is a prospective, randomized investigation. The study will be performed in the Department of General, Emergency and Transplant Surgery St Orsola-Malpighi University Hospital (Bologna, Italy), a large teaching institutions, with the participation of all surgeons who accept to be involved in (and together with other selected centers). The patients will be divided in two groups: in the first group the patient will be submitted to laparoscopic cholecystectomy within 72 hours after the diagnosis while in the second group will be submitted to laparotomic cholecystectomy within 72 hours after the diagnosis. TRIAL REGISTRATION: TRIAL REGISTRATION NUMBER ISRCTN27929536 - The ACTIVE (Acute Cholecystitis Trial Invasive Versus Endoscopic) study. A multicentre randomised, double-blind, controlled trial of laparoscopic versus open surgery for acute cholecystitis in adults.

Six3 controls the neural progenitor status in the murine CNS.

Six3, a homeodomain-containing transcriptional regulator belonging to the Six/so family, shows a defined spatiotemporal expression pattern in the developing murine telencephalon, suggesting that it may control the development of specific subsets of neural progenitors. We find that retrovirus-mediated misexpression of Six3 causes clonal expansion of isolated cortical progenitor cells by shortening their cell cycle and by prolonging their amplification period, while maintaining them in an immature precursor state. Our results show that the observed effects exerted by Six3 overexpression in mammalian brain depend strictly on the integrity of its DNA-binding domain, suggesting that Six3 action likely relies exclusively on its transcriptional activity. In vivo upregulation of Six3 expression in single progenitor cells of the embryonic telencephalon keeps them in an undifferentiated state. Our observations point to a role of Six3 in the control of the subtle equilibrium between proliferation and differentiation of defined precursor populations during mammalian neurogenesis.

Radial glia and neural stem cells.

During the last decade, the role of radial glia has been radically revisited. Rather than being considered a mere structural component serving to guide newborn neurons towards their final destinations, radial glia is now known to be the main source of neurons in several regions of the central nervous system, notably in the cerebral cortex. Radial glial cells differentiate from neuroepithelial progenitors at the beginning of neurogenesis and share with their ancestors the bipolar shape and the expression of some molecular markers. Radial glia, however, can be distinguished from neuroepithelial progenitors by the expression of astroglial markers. Clonal analyses showed that radial glia is a heterogeneous population, comprising both pluripotent and different lineage-restricted neural progenitors. At late-embryonic and postnatal stages, radial glial cells give rise to the neural stem cells responsible for adult neurogenesis. Embryonic pluripotent radial glia and adult neural stem cells may be clonally linked, thus representing a lineage displaying stem cell features in both the developing and mature central nervous system.