A new surgical positioning system for robotic assisted minimally invasive spine surgery and transpedicular approach to the disc.

Minimally Invasive Spine Surgery (MISS) procedures for the treatment of spinal pathologies have experienced exponential growth due to improved techniques and decreased trauma to the patient. Several MISS procedures that require the use of a trans-pedicular cannula as a guiding tool for pedicle screw placement, delivery of biomaterials to the vertebral body or injection of biologics to the disc space have been described. Although these are clear advantages of MISS, the limited dissection and exposure may reduce the accuracy and stability of operation and make spine surgeons rely heavily on intraoperative fluoroscopy, raising concerns over the level of radiation exposure. Robot-assisted minimal invasive surgery has aroused more attention for its high precision and stability, minimizing risks of damage to neurovascular structures and diminishing harmful exposure to ionizing radiation. The aim of this paper is to describe and characterize a new surgical positioning system for for robotic assisted MISS. The system is conceived to be integrated in a surgical platform capable of supporting the surgeon in a new procedure to treat degenerative intervertebral disc disease. For this purpose, it is necessary to orientate a cannula in order to guide the bone drill along a planned route, to access the intervertebral disc through the pedicle and endplate. In particular, we describe a mechanism that percutaneously guides a cannula towards the intervertebral disc based on the acquisition of few fluoroscopic images. The design of the positioning system, with its features and constrains imposed by the presence of instrumentation and medical staff in the operating room, as well as the software for trajectory planning during surgery, are here described.

Occupational exposure to PCDDs, PCDFs, and DL-PCBs in metallurgical plants of the Brescia (Lombardy Region, northern Italy) area.

The concentration values of polychlorodibenzodioxins (PCDDs), polychlorodibenzofurans (PCDFs), and dioxin-like polychlorobiphenyls (DL-PCBs) in blood serum samples (pools) of metallurgical workers in the area of the city of Brescia (northern Italy) were statistically processed. As to workers' exposure characteristics, pools were divided into 34 professionally exposed (PE) and 11 non-professionally exposed (NPE). A further subdivision of PE pools was according to workplaces in which ferrous (N = 24) and non-ferrous (N = 10) materials were handled. To evaluate the aforesaid differences we applied the age-adjusted Generalized Linear Models. We identified significant (P ≤ 0.05) exposure models of the classification groups. The first subdivision was confirmed by the concentrations of 1,2,3,4,6,7,8-H7CDF, DL-PCB 105, and DL-PCB 189; the second was confirmed by the concentrations of PCDF TEQ97, PCDD + PCDF + DL-PCB (TEQTOT) TEQ97, 2,3,4,7,8-P5CDF, 1,2,3,6,7,8-H6CDD, 1,2,3,4,6,7,8-H7CDD, and PCB 189. Based on the literature, all mentioned congeners have been found in stack gas and fly ash samples of metallurgical plants: therefore, these indicators indicate the exposure to such work environments. Specifically, the concentrations measured in the workers' blood serum appear to depend on the type of material processed during work.

Monte Carlo as a tool to evaluate the effect of different lung densities on radiotherapy dose distribution.

This study aims at evaluating the effects of different lung densities on dose distribution after irradiation at different field sizes, by comparing experimental measurements, GEANT4 Monte Carlo (MC) simulations and two TPS calculation algorithms on ad hoc phantoms. Irradiations were performed with a Varian Clinac 2100 C/D with a nominal energy of 6 MV. Dosimetric experimental measurements were obtained with radiochromic films. A model based on GEANT4 MC code was developed to simulate both the accelerator and the phantoms. Results of dose distribution show an acceptable agreement between MC simulations and experimental measurements, both in the tumour-equivalent region and in the normal tissue-equivalent ones. On the opposite, results vary among the TPS algorithms, especially in regions of lung-equivalent material at low density, but also at the interface between lung- and tumour-equivalent materials.

New ligands of the Cellular Retinoic Acid-Binding Protein 2 (CRABP2) suggest a role for this protein in chromatin remodeling

Retinoic acid (RA) regulates the transcription of a series of genes involved in cell proliferation, differentiation and apoptosis by binding to the RA Receptor (RAR) and Retinoid X Receptor (RXR) heterodimers. The cellular retinoic acid-binding protein 2 (CRABP2) is involved in the transport of RA from the cytosol to specific RA receptors in the nucleus, acting as a coactivator of nuclear retinoid receptors. In order to have a better understanding of the role of CRABP2 in RA signaling, we used the yeast two-hybrid system as a tool for the identification of physical protein-protein interactions. Twenty-three putative CRABP2-interacting proteins were identified by screening in the presence of RA, five of which are related to transcription regulation or, more specifically, to the process of chromatin remodeling: t-complex 1 (TCP1); H3 histone, family 3A (H3F3A); H3 histone, family 3B (H3F3B); β-tubulin (TUBB) and SR-related CTD-associated factor 1 (SCAF1). These results suggest a more direct role for CRABP2 in chromatin remodeling and may be a starting point for the elucidation of the fine-tuning control of transcription by RA receptors...

Papel da proteína Mx1 na resposta a interferons e no processo neoplásico / Role of Mx1 protein in the response to interferons and neoplastic process

A proteína Mx1 é codificada por um gene induzido por interferon e compartilha a organização de seus domínios, a capacidade de homo-oligomerização e associação com membranas com as grandes dinaminas GTPases. A proteína Mx1 está envolvida na resposta contra um grande número de vírus de RNA, como aqueles pertencentes à família Buniavírus e o vírus influenza. Curiosamente, o gene MX1 foi encontrado como silenciado por metilação em diversos processos neoplásicos, incluindo carcinomas de cabeça e pescoço de células escamosas. Neste cenário, o silenciamento gênico de MX1 está associado à imortalização de uma série de linhagens celulares neoplásicas. Assim, Mx1 se destaca como uma das principais proteínas envolvidas nas respostas imunes induzidas por interferon e também desempenha um importante papel no controle do ciclo celular. Aqui discutimos os aspectos funcionais da proteína Mx1 abordando sua atividade antiviral, organização estrutural, envolvimento com neoplasias e, principalmente, os aspectos funcionais obtidos pela determinação de seus parceiros celulares.

The Mx1 protein is encoded by an interferon-induced gene and shares domain organization, homo-oligomerization capacity and membrane association with the large dynamin-like GTPases. The Mx1 protein is involved in the response to a large number of RNA viruses, such as the bunyavirus family and the influenza virus. Interestingly, it has also been found as a methylation-silenced gene in several types of neoplasm, including head and neck squamous cell carcinoma. In this scenario, MX1 gene silencing is associated with immortalization in several neoplastic cell lines. Thus, Mx1 stands out as one of the key proteins involved in interferon-induced immune response and also plays an important role in cell cycle control. Here we discuss some of the functions of the Mx1 protein, including its antiviral activity, protein folding and involvement in neoplasia, as well as those revealed by investigating its cellular partners.

Obtenção de derivado de celulose a partir do bagaço de cana-de-açúcar com potencial aplicação nas indústrias farmacêutica e cosmética / Assessment of a gel derived from sugarcane bagasse cellulose

A tendência de se buscar o desenvolvimento de novos veículos agregando sustentabilidade e qualidade é o desafio da pesquisa farmacêutica. Assim, a busca de novas fontes de matéria-prima parece ocupar uma grande parcela dos estudos e investimentos do setor farmacêutico. Desse modo, a celulose é um exemplo de matéria-prima com alta aplicabilidade nas indústrias farmacêutica e cosmética. Temos na natureza algumas espécies de angiospermas com potencial fornecimento de celulose, tais como coco, bambu, cana-de-açúcar, entre outras. Destas, o bagaço de cana-de-açúcar apresenta teores de celulose significativos para obtenção de compostos derivados. O Brasil ocupa o primeiro lugar na produção de etanol e açúcar através da utilização da cana-de-açúcar. O presente trabalho teve como objetivo avaliar uma dispersão obtida a partir de um composto derivado da celulose extraída do bagaço de cana-de-açúcar.

The development of new vehicles combining sustainability and quality is a challenge facing pharmaceutical research. Thus, the search for novel raw material sources seems to occupy a great portion of the studies and investments of the pharmaceutical sector. One example of such a raw material with wide applicability in the pharmaceutical and cosmetics industries is cellulose. There are several angiosperm species with potential as suppliers of cellulose, such as coconut, bamboo and sugarcane, to name a few found in Brazil. Bagasse, the fibrous residue from crushed sugarcane, has a significant cellulose content from which new compounds can be derived. Brazil currently occupies first place in the production of ethanol and sugar from sugarcane. The aim of the present study was to assess a dispersion obtained from a derivative of the cellulose extracted from sugarcane pulp.

Lung transplantation for cystic fibrosis in Italy.

Lung transplantation (LT) is the only effective form of therapy for cystic fibrosis (CF) associated with end-stage pulmonary failure. In Italy, the management of CF is regulated by national law, which has instituted regional centers for care and follow-up of all CF patients. LT has been performed since 1992 in only nine LT certified centers. The structured national organization has led to a unified database for LT for CF. As of December 2006, 197 bilateral LT (96 male and 94 female patients; 7 retransplants) have been performed. Of these, four had also liver or heart and liver transplantation, and three are long-term survivors. Overall median survival is 7 years. Mean age at transplantation is 26.5 years, and the mortality on the waiting list is 33.6%. Patients listed for transplant either received a suitable donor within a mean of 10 months or died within a mean of 5.5 months. The most frequent cause of death is bronchiolitis obliterans syndrome (BOS). Our nationwide database indicates the excellent results obtained by LT in FC. Still, mortality on the waiting list remains a challenge and long-term outcome is limited by BOS.

Does cystic fibrosis neonatal screening detect atypical CF forms? Extended genetic characterization and 4-year clinical follow-up.

The neonatal screening protocol for cystic fibrosis (CF) is based on a first determination of blood immunoreactive trypsin (IRT1), followed by a first level genetic test that includes the 31 worldwide most common mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene (DNA31), and a second determination of blood immunoreactive trypsin (IRT2). This approach identifies, in addition to affected subjects, a high proportion of newborns with hypertrypsinaemia at birth, in whom only one mutation is identified and who have a negative or borderline sweat test and pancreatic sufficiency. Although it has been suggested that hypertrypsinaemia may be caused by a single CFTR mutation, whether such neonates should be merely considered as healthy carriers remains a matter of debate as hypertrypsinaemia at birth may be a biochemical marker of a CFTR malfunction because of a second mild mutation. We analyzed, by means of an extended sequencing protocol, 32 newborns who tested positive at an IRT1/DNA31/IRT2 screening protocol and in whom only one CFTR mutation was found. The results obtained demonstrate that 62.5% of these newborns were also carrying a second mild CFTR mutation. The high proportion of compound heterozygous subjects, combined with the results of a 4-year follow-up in nine of these subjects all of whom displaying initial CF clinical symptoms, suggest that it may be possible to use the IRT1/DNA31/IRT2 protocol of neonatal screening to identify newborns with atypical forms of CF. In view of these findings, an extended genetic search for subjects with compound heterozygosity and a periodic clinical assessment should be considered.

The performance of poly-epsilon-caprolactone scaffolds in a rabbit femur model with and without autologous stromal cells and BMP4.

The ability of a cellular construct to guide and promote tissue repair strongly relies on three components, namely, cell, scaffold and growth factors. We aimed to investigate the osteopromotive properties of cellular constructs composed of poly-epsilon-caprolactone (PCL) and rabbit bone marrow stromal cells (BMSCs), or BMSCs engineered to express bone morphogenetic protein 4 (BMP4). Highly porous biodegradable PCL scaffolds were obtained via phase inversion/salt leaching technique. BMSCs and transfected BMSCs were seeded within the scaffolds by using an alternate flow perfusion system and implanted into non-critical size defects in New Zealand rabbit femurs. In vivo biocompatibility, osteogenic and angiogenic effects induced by the presence of scaffolds were assessed by histology and histomorphometry of the femurs, retrieved 4 and 8 weeks after surgery. PCL without cells showed scarce bone formation at the scaffold-bone interface (29% bone/implant contact and 62% fibrous tissue/implant contact) and scarce PCL resorption (16%). Conversely, PCL seeded with autologous BMSCs stimulated new tissue formation into the macropores of the implant (20%) and neo-tissue vascularization. Finally, the BMP4-expressing BMSCs strongly favoured osteoinductivity of cellular constructs, as demonstrated by a more extensive bone/scaffold contact.

Use of a synthetic lethal screen to identify genes related to TIF51A in Saccharomyces cerevisiae

The putative eukaryotic translation initiation factor 5A (eIF5A) is an essential protein for cell viability and the only cellular protein known to contain the unusual amino acid residue hypusine. eIF5A has been implicated in translation initiation, cell proliferation, nucleocytoplasmic transport, mRNA decay, and actin polarization, but the precise biological function of this protein is not clear. However, eIF5A was recently shown to be directly involved with the translational machinery. A screen for synthetic lethal mutations was carried out with one of the temperature-sensitive alleles of TIF51A (tif51A-3) to identify factors that functionally interact with eIF5A and revealed the essential gene YPT1. This gene encodes a small GTPase, a member of the rab family involved with secretion, acting in the vesicular trafficking between endoplasmatic reticulum and the Golgi. Thus, the synthetic lethality between TIF51A and YPT1 may reveal the connection between translation and the polarized distribution of membrane components, suggesting that these proteins work together in the cell to guarantee proper protein synthesis and secretion necessary for correct bud formation during G1/S transition. Future studies will investigate the functional interaction between eIF5A and Ypt1 in order to clarify this involvement of eIF5A with vesicular trafficking.

eIF5A: uma proteína essencial para a viabilidade celular cuja função permanece obscura / eIF5A: an essential protein for cell viability whose function remains obscure

O provável fator de início de tradução 5A (eIF5A) é uma proteína abundante e altamente conservada em todos os organismos eucarióticos observados e também está presente em arquebactérias. eIF5A é essencial para aviabilidade celular e esse fator é a única proteína descrita que contém o resíduo de aminoácido hipusina. Em Saccharomyces cerevisiae, eIF5A é expressa em condições aeróbicas pelo gene TIF51A. Apesar de eIF5A ser conhecida há quase 30 anos, a sua função biológica ainda é obscura. Este artigo revisa os estudos de caracterização funcional de eIF5A, evidenciando como esse fator foi envolvido com diferentes etapas do metabolismo de RNA mensageiro (mRNA), como o início de tradução, o transporte nucleocitoplasmático e o decaimento de RNA mensageiro. Ainda, estudos que evidenciaram o envolvimento de eIF5A com a proliferação celular e progressão no ciclo celular também foram abordados. Finalmente, esse artigo apresenta os resultados recentes dos experimentos que colocam eIF5A novamente no cenário da tradução. Novos experimentos serão necessários para definir o papel desempenhado por eIF5A na maquinaria de tradução.

Damaging effects of advanced glycation end-products in the murine macrophage cell line J774A.1.

The interaction of reducing sugars, such as aldose, with proteins and the subsequent molecular rearrangements, produces irreversible advanced glycation end-products (AGEs), a heterogeneous class of non-enzymatic glycated proteins or lipids. AGEs form cross-links, trap macromolecules and release reactive oxygen intermediates. AGEs are linked to aging, and increase in several related diseases. The aim of this study was to assess, in a murine macrophage cell line, J774A.1, the effects of 48 h of exposure to glycated serum containing a known amount of pentosidine, a well-known AGE found in the plasma and tissues of diabetic and uremic subjects. Fetal bovine serum was incubated with ribose (50 mM) for 7 days at 37 degrees C to obtain about 10 nmol/ml of pentosidine. The cytotoxic parameters studied were cell morphology and viability by neutral red uptake, lactate dehydrogenase release and tetrazolium salt test. In the medium and in the intracellular compartment, bound and free pentosidine were evaluated by HPLC, as sensitive and specific glycative markers, and thiobarbituric acid reactive substances (TBARs), as index of the extent of lipid peroxidation. Our results confirm that macrophages are able to take up pentosidine. It is conceivable that bound pentosidine is degraded and free pentosidine is released inside the cell and then into the medium. The AGE increase in the medium was combined with an increase in TBARs, meaning that an oxidative stress occurred; marked cytotoxic effects were observed, and were followed by the release of free pentosidine and TBARs into the culture medium.

Oncological results of endoscopic resections of Tis and T1 glottic carcinomas by carbon dioxide laser.

A cohort of 88 patients with glottic cancer (13 Tis, 75 T1) who underwent endoscopic CO2 laser excision between January 1995 and June 1997 was prospectively studied. The mean follow-up was 43 months (range, 30 to 60 months). The depth and extent of the excision (graded according to the European Laryngological Society Classification, which includes 5 types of resection) were based on the results of a preoperative and intraoperative diagnostic test battery. Five patients died of other diseases, and none of glottic cancer. Of the 12 patients who developed a local recurrence, 5 underwent a second endoscopic procedure, 5 a total laryngectomy, and 1 a supracricoid laryngectomy, and 1 was treated with radiotherapy. The 5-year local control rate with endoscopic surgery alone, according to the Kaplan-Meier method, was 91%. None of the variables (8 related to the tumor and 2 to the treatment) tested in a univariate analysis by the log-rank test was found to have a significant impact on disease-free survival rates. The present study confirmed that endoscopic partial cordectomy for Tis and T1 glottic cancers can be regarded as a valid alternative to radiotherapy in terms of oncological results.

Plasma protein oxidation and antioxidant defense during aging.

BACKGROUND: Oxidative stress is an important process that occurs in vivo during aging and is considered one of the main causes of molecular damage to cellular and tissue structures. These changes can accumulate in biological structures during aging. OBJECTIVE: The aim of this work is to evaluate plasma protein oxidative damage, measured as carbonyl groups content, and the concentration of some antioxidant molecules (vitamins and carotenoids) in 122 healthy volunteers (50 males and 72 females), 25 to 89 years old. RESULTS: Total plasma proteins slightly decreased with age, but the level of carbonyl groups was similar in the adult (< 65 years) and in the old, and was similar in both sexes. Plasma concentration of antioxidant molecules such as alpha-tocopherol, beta-carotene and other carotenoids, increased with age and correlated with the level of lipoproteins; plasma total cholesterol and triglycerides were significantly correlated with age as well. CONCLUSIONS: The surprisingly normal level of plasma protein carbonyl groups in our older subjects suggests two possibilities: a) the older people in our study are healthy and free from pathologies because of better protection against oxidative injury during their lifetimes, i.e., they maintained low-level oxidative damage on plasma proteins; or b) the level of carbonyl groups is normal because of the high turnover in plasma: the oxidized circulating proteins are preferentially and quickly removed; in this case oxidative damage is not discernible in plasma proteins but may proceed silently in other tissues.

Arginine methylation and binding of Hrp1p to the efficiency element for mRNA 3'-end formation.

Hrp1p is a heterogeneous ribonucleoprotein (hnRNP) from the yeast Saccharomyces cerevisiae that is involved in the cleavage and polyadenylation of the 3'-end of mRNAs and mRNA export. In addition, Hrplp is one of several RNA-binding proteins that are posttranslationally modified by methylation at arginine residues. By using functional recombinant Hrp1p, we have identified RNA sequences with specific high affinity binding sites. These sites correspond to the efficiency element for mRNA 3'-end formation, UAUAUA. To examine the effect of methylation on specific RNA binding, purified recombinant arginine methyltransferase (Hmt1p) was used to methylate Hrp1p. Methylated Hrp1p binds with the same affinity to UAUAUA-containing RNAs as unmethylated Hrpl p indicating that methylation does not affect specific RNA binding. However, RNA itself inhibits the methylation of Hrp1p and this inhibition is enhanced by RNAs that specifically bind Hrpl p. Taken together, these data support a model in which protein methylation occurs prior to protein-RNA binding in the nucleus.

Cervical neuroma presenting as a subarachnoid hemorrhage: case report.

OBJECTIVE AND IMPORTANCE: The association of subarachnoid hemorrhage (SAH) with spinal lesions is well known, but hemorrhage from a cervical schwannoma is exceedingly rare. The histopathology and the mechanism of bleeding are discussed. CLINICAL PRESENTATION: We report a healthy 37-year-old man presenting with SAH after intense physical stress caused by bleeding of a cervical neuroma. INTERVENTION: A C6-T1 laminectomy disclosed an ovoid lesion, 4 cm in diameter; extremely dilated veins originated from the tumor. Removal of the spinal lesion resulted in immediate decongestion of the related venous network. The histopathological examination confirmed that the lesion was a telangiectatic schwannoma. The mechanism of bleeding of the intraforaminal cervical schwannoma is discussed. CONCLUSION: Telangiectatic neuromas may be a cause of occult SAH. The importance of magnetic resonance imaging of the cervical spine is emphasized to explain SAH with negative findings on four-vessel angiography in patients whose SAH may have a surgically correctable cause distant from the intracranial compartment.

Molecular genetic approach to cell proliferation control and neoplasia.

A number of gene products involved in the control of cell proliferation fall into one of two classes: oncogenes and tumor suppressor genes. The same gene products have also been associated with malignant growth (tumors) caused by radiation, chemicals and tumor viruses. Here we describe our attempts to elucidate the molecular mechanisms underlying polyomavirus-induced cell transformation and the anti-tumor activity of glucocorticoid hormones. Wild type and mutant polyomavirus middle T (MT) overexpressing cell lines, generated with retroviral vector constructs, were used to investigate the role played by peptide growth factor primary response genes (fos, jun, myc, JE, KC) in viral transformation and to map the transduction pathway of the mitogenic signal of MT. Overexpression of MT leads to increased AP-1 (Fos/Jun) transcriptional complex activity. Transformation defective mutant analysis allowed the identification of sites in the MT molecule that are crucial for this activity. Two different approaches were used to investigate the molecular basis for glucocorticoids anti-tumor activity, namely: blind cloning of cDNAs and analysis of growth control genes in C6 glioma cell variants that are either hypersensitive (C6/ST1) or unresponsive to glucocorticoids (C6/P7). Four different glucocorticoid-regulated cDNA sequences were isolated using differential hybridization. A number of differentially expressed sequences were isolated from glucocorticoid-treated C6/ST1 cells by differential display (DDRT-PCR) and are currently being characterized. Expression of known growth control genes in C6/ST1 cells allowed the identification of important candidates for glucocorticoid hormone targets.

Molecular genetic approach to cell proliferation control and neoplasia

A number of gene products involved in the control of cell proliferation fall into one of two classes: oncogenes and tumor suppressor genes. The same gene products have also been associated with malignant growth (tumors) caused by radiation, chemicals and tumor viruses. Here we describe our attempts to elucidate the molecular mechanisms underlying polyomavirus-induced cell transformation and the anti-tumor activity of glucocorticoid hormones. Wild type and mutant polyomavirus middle T (MT) overexpressing cell lines, generated with retroviral vector constructs, were used to investigate the role played by peptide growth factor primary response genes (fos, jun, myc, JE, KC) in viral transformation and to map the transduction pathway of the mitogenic signal of MT. Overexpression of MT leads to increased AP-1 (Fos/Jun) transcriptional complex activity. Transformation defective mutant analysis allowed the identification of sites in the MT molecule that are crucial for this activity. Two different approaches were used to investigate the molecular basis for glucocorticoids anti-tumor activity, namely: blind cloning of cDNAs and analysis of growth control genes in C6 glioma cell variants that are either hypersensitive (C6/ST1) or unresponsive to glucocorticoids (C6/P7). Four different glucocorticoid-regulated cDNA sequences were isolated using differential hybridization. A number of differentially expressed sequences were isolated from glucocorticoid-treated C6/ST1 cells by differential display (DDRT-PCR) and are currently being characterized. Expression of known growth control genes in C6/ST1 cells allowed the identification of important candidates for glucocorticoid hormone targets.

Cloning of glucocorticoid-regulated genes in C6/ST1 rat glioma phenotypic reversion.

The C6 rat glioma cell line is response to glucocorticoid hormones. C6 variants that are hyper-responsive (ST1) and resistant (P7) to hormone treatment have been derived previously. Glucocorticoid treatment of ST1 cells leads to complete reversion of the transformed phenotype and loss of tumorigenic potential. Production of C type retrovirus particles is also induced by glucocorticoids in ST1 cells. Cloning of the genes regulated by glucocorticoids in this cell system was used here as a strategy to uncover the gene products involved in the transformed-to-normal phenotypic change. Construction of a cDNA library from glucocorticoid-treated ST1 cells and screening by differential hybridization resulted in the isolation of three cellular sequences that code for rat metallothioneins (C27 and C41) and alpha 1-acid glycoprotein (C36). Northern blot analysis revealed that expression of these genes was dramatically induced by hydrocortisone in ST1 but not in P7 cells. Viral genomic RNA was used to isolate and characterize retrovirus-related sequences that could also be responsible for the phenotypic reversion phenomenon.