GoT-Splice protocol for multi-omics profiling of gene expression, cell-surface proteins, mutational status, and RNA splicing in human cells.

Studying RNA splicing factor mutations is challenging due to difficulties in distinguishing wild-type and mutant cells within complex human tissues and inaccuracies associated with reconstructing splicing signals from short-read sequencing data. Here, we present Genotyping of Transcriptomes (GoT)-Splice, a protocol that overcomes these limitations by combining GoT with enhanced long-read single-cell transcriptome and cell-surface proteomics profiling. We describe steps for long-read library preparation and analysis, followed by cDNA re-amplification, enrichment of mutation of interest, sample indexing, and GoT library preparation. For complete details on the use and execution of this protocol, please refer to Cortés-López et al.1.

Single-cell multi-omics defines the cell-type-specific impact of splicing aberrations in human hematopoietic clonal outgrowths.

RNA splicing factors are recurrently mutated in clonal blood disorders, but the impact of dysregulated splicing in hematopoiesis remains unclear. To overcome technical limitations, we integrated genotyping of transcriptomes (GoT) with long-read single-cell transcriptomics and proteogenomics for single-cell profiling of transcriptomes, surface proteins, somatic mutations, and RNA splicing (GoT-Splice). We applied GoT-Splice to hematopoietic progenitors from myelodysplastic syndrome (MDS) patients with mutations in the core splicing factor SF3B1. SF3B1mut cells were enriched in the megakaryocytic-erythroid lineage, with expansion of SF3B1mut erythroid progenitor cells. We uncovered distinct cryptic 3' splice site usage in different progenitor populations and stage-specific aberrant splicing during erythroid differentiation. Profiling SF3B1-mutated clonal hematopoiesis samples revealed that erythroid bias and cell-type-specific cryptic 3' splice site usage in SF3B1mut cells precede overt MDS. Collectively, GoT-Splice defines the cell-type-specific impact of somatic mutations on RNA splicing, from early clonal outgrowths to overt neoplasia, directly in human samples.

Recurrence Rates for Pediatric Benign Ovarian Neoplasms.

STUDY OBJECTIVE: To examine the recurrence rates of pediatric benign ovarian neoplasms METHODS: A retrospective review of females up to 21 years of age who underwent surgery for a benign ovarian neoplasm at 8 pediatric hospitals from January 2010 through December 2016 was conducted. Data include primary operation details, follow-up imaging, and reoperation details. RESULTS: Four hundred and twenty-six females were included in our cohort, with a median age of 15 years at the time of the primary operation. Of the patients, 69% had a mature teratoma, 18% had a serous cystadenoma, and 8% had a mucinous cystadenoma. Two-thirds of patients underwent ovarian-sparing surgery. There were 11 pathologically confirmed recurrences (2.6%) at a median follow-up of 12.8 months. The pathologically confirmed recurrence was 10.5 per 100 person-months at 12 months (SE = 5.7) for mucinous cystadenomas and 0.4 months (SE = 0.4) for mature teratomas (P = .001). For half of the patients, the pathologically confirmed recurrences occurred by 12.8 months, and for 75%, they occurred by 23.3 months. There were no differences in reoperation or recurrence on the basis of initial procedure (ovary-sparing surgery vs oophorectomy). CONCLUSION: We measured the pathologically confirmed recurrence rate for pediatric benign ovarian neoplasms in a large cohort. Oophorectomy was not protective against recurrence. Mucinous cystadenomas were at a greater risk of pathologically confirmed recurrence.

Failure of Operative Therapy after Ovarian-Sparing Surgery for Pediatric Benign Ovarian Neoplasms: A Retrospective Review.

STUDY OBJECTIVE: To evaluate failure of initial operative therapy (incomplete tumor removal) of ovarian-sparing surgery for pediatric benign ovarian neoplasms. METHODS: A retrospective review of patients up to 21 years of age who underwent ovarian-sparing surgery for a benign ovarian neoplasm from 2010 to 2016 at 8 pediatric hospitals was conducted. Failure of initial operative therapy is defined as a radiologically suspected or pathologically confirmed ipsilateral lesion with the same pathology as the primary neoplasm within 12 weeks of the initial operation. RESULTS: Forty patients received imaging within 12 weeks of their primary operation. Sixteen (40%) patients had a radiologically identified ovarian abnormality ipsilateral to the primary lesion, and 5 patients were suspected to have the same lesion as their primary neoplasm. Three of the 5 patients (7.5%) underwent reoperation with pathologic confirmation of the same lesion, resulting in a pathologically confirmed failure of therapy rate of 7.5%. The other 2 patients had serial imaging that subsequently demonstrated no recurrence with lesion resolution. Age, race/ethnicity, laparoscopy vs laparotomy, presence of torsion, pathology, size of lesion, and surgeon specialty were not associated with failure of therapy. CONCLUSION: In most patients who received imaging within 12 weeks of the primary operation for resection of a benign ovarian neoplasm, ovarian-sparing surgery was successful in complete tumor removal, with a low failure of therapy rate. Selected patients with suspected failure of therapy on initial imaging could be serially monitored to determine the need for repeat surgical intervention.

EWS::FLI1 and HOXD13 Control Tumor Cell Plasticity in Ewing Sarcoma.

PURPOSE: Propagation of Ewing sarcoma requires precise regulation of EWS::FLI1 transcriptional activity. Determining the mechanisms of fusion regulation will advance our understanding of tumor progression. Here we investigated whether HOXD13, a developmental transcription factor that promotes Ewing sarcoma metastatic phenotypes, influences EWS::FLI1 transcriptional activity. EXPERIMENTAL DESIGN: Existing tumor and cell line datasets were used to define EWS::FLI1 binding sites and transcriptional targets. Chromatin immunoprecipitation and CRISPR interference were employed to identify enhancers. CUT&RUN and RNA sequencing defined binding sites and transcriptional targets of HOXD13. Transcriptional states were investigated using bulk and single-cell transcriptomic data from cell lines, patient-derived xenografts, and patient tumors. Mesenchymal phenotypes were assessed by gene set enrichment, flow cytometry, and migration assays. RESULTS: We found that EWS::FLI1 creates a de novo GGAA microsatellite enhancer in a developmentally conserved regulatory region of the HOXD locus. Knockdown of HOXD13 led to widespread changes in expression of developmental gene programs and EWS::FLI1 targets. HOXD13 binding was enriched at established EWS::FLI1 binding sites where it influenced expression of EWS::FLI1-activated genes. More strikingly, HOXD13 bound and activated EWS::FLI1-repressed genes, leading to adoption of mesenchymal and migratory cell states that are normally suppressed by the fusion. Single-cell analysis confirmed that direct transcriptional antagonism between HOXD13-mediated gene activation and EWS::FLI1-dependent gene repression defines the state of Ewing sarcoma cells along a mesenchymal axis. CONCLUSIONS: Ewing sarcoma tumors are comprised of tumor cells that exist along a mesenchymal transcriptional continuum. The identity of cells along this continuum is, in large part, determined by the competing activities of EWS::FLI1 and HOXD13. See related commentary by Weiss and Bailey, p. 4360.

Laparoscopy versus laparotomy for pediatric ovarian dermoids.

BACKGROUND: With increased surgeon comfort using laparoscopy, we hypothesized resection of pediatric ovarian dermoids using laparoscopy would yield a shorter length of stay and no increase in morbidity or recurrence compared to laparotomy. METHODS: A retrospective review was performed amongst eleven pediatric hospitals. Patients aged 2 to 21 who underwent resection of an ovarian dermoid from 2010 to 2020 were included. Patient characteristics, operative details, and outcomes by approach were evaluated using Chi-squared and Wilcoxon-Mann tests. RESULTS: 466 patients were included, with a median age of 14.4 and median follow-up of 4.0 months. 279 patients underwent laparoscopy (60%), 139 laparotomy (30%), and 48 laparoscopy converted to laparotomy (10%). There were no differences in rates of tumor spillage by approach (p = 0.15). 65% underwent ovarian-sparing surgery and 35% underwent oophorectomy. Length of stay was significantly shorter amongst patients who underwent laparoscopy (1 day versus 2 days for laparotomy and converted, p<0.0001). There were no differences in rates of suspected recurrence or reoperation (p = 0.19 and p = 0.57, respectively). CONCLUSION: Patients who underwent laparoscopy experienced no differences in the rates of tumor spillage, recurrence, or reoperation and had a shorter length of stay compared to laparotomy. Laparoscopy is an acceptable approach for resection of pediatric ovarian dermoids.

Multi-Institutional Review of the Preoperative Diagnostic Accuracy for Pediatric Ovarian Mature Cystic Teratomas.

STUDY OBJECTIVE: To assess the preoperative imaging impression and surgeon diagnostic accuracy for pediatric ovarian mature cystic teratomas (MCTs) DESIGN: Retrospective review SETTING: Eleven pediatric hospitals PARTICIPANTS: Patients ages 2 to 21 who underwent surgical management of an ovarian neoplasm or adnexal torsion with an associated ovarian lesion INTERVENTION: None MAIN OUTCOME MEASURES: Preoperative imaging impression, surgeon diagnosis, tumor markers, and pathology RESULTS: Our cohort included 946 females. Final pathology identified 422 (45%) MCTs, 405 (43%) other benign pathologies, and 119 (12%) malignancies. Preoperative imaging impression for MCTs had a 70% sensitivity, 92% specificity, 88% positive predictive value (PPV), and 79% negative predictive value (NPV). For the preoperative surgeon diagnosis, sensitivity was 59%, specificity 96%, PPV 92%, and NPV 74%. Some measures of diagnostic accuracy were affected by the presence of torsion, size of the lesion on imaging, imaging modality, and surgeon specialty. Of the 352 masses preoperatively thought to be MCTs, 14 were malignancies (4%). Eleven patients with inaccurately diagnosed malignancies had tumor markers evaluated and 82% had at least 1 elevated tumor marker, compared with 49% of those with MCTs. CONCLUSIONS: Diagnostic accuracy for the preoperative imaging impression and surgeon diagnosis is lower than expected for pediatric ovarian MCTs. For all ovarian neoplasms, preoperative risk assessment including a panel of tumor markers and a multidisciplinary review is recommended. This process could minimize the risk of misdiagnosis and improve operative planning to maximize the use of ovarian-sparing surgery for benign lesions and allow for appropriate resection and staging for lesions suspected to be malignant.

Parental Responses to Coming out by Lesbian, Gay, Bisexual, Queer, Pansexual, or Two-Spirited People across Three Age Cohorts.

OBJECTIVE: The study aimed to better understand the complexities of parental responses to coming out in the narratives from Lesbian, Gay, Bisexual, Queer, Pansexual, or Two-Spirited (LGBQ+) individuals, and to examine whether those from recent cohorts experience a different parental response than those in older cohorts. BACKGROUND: Sexual minorities come out at younger ages today than in past decades, and coming out to parents is a major part of the identification process. METHOD: Interview excerpts of 155 US lesbian, gay, bisexual, queer, pansexual, or two-spirited (LGBQ+) respondents were analyzed with a qualitative thematic analysis and with basic quantitative methods. The sample consisted of 61 interviewees in a young cohort (ages 18-25), 65 in a middle cohort (ages 35-42), and 29 in an older cohort (ages 52-59), in six ethnic/racial groups. RESULTS: Themes based on LGBQ+ people's accounts indicated that parental responses varied with the degree of their a priori knowledge of respondents' sexual identities (ranging from suspicion or certainty to surprise). Parental appraisal was either lacking, negative, mixed, or positive with accompanying silent, invalidating, ambivalent, and validating responses, respectively. Validating responses from parents were more often found in the youngest cohort, but invalidating responses were frequent across all cohorts. LGBQ+ people in the oldest cohort were more inclined to accept their parents being noncommunicative about sexuality in general and also about sexual diversity. CONCLUSION: It is too early to state that coming out to parents has become easier. Harmony in the parent-child relationship after coming out and open communication about sexual identities is regarded as desirable and yet it remains elusive for many LGBQ+ people.

Recommendations for Postoperative Surveillance of Pediatric Benign Ovarian Neoplasms.

STUDY OBJECTIVE: To assess postoperative management of pediatric patients with benign ovarian neoplasms, to develop recommendations for postoperative care. DESIGN: A retrospective cohort study. SETTING: Eight pediatric hospitals in the midwestern United States. PARTICIPANTS: Patients up to 21 years of age who underwent surgery for a benign ovarian neoplasm between January 2010 and December 2016 were included. INTERVENTIONS: No prospective interventions were evaluated. MAIN OUTCOME MEASURES: Main outcome measures included postoperative imaging findings, recurrence rates, reoperation rates, and the timing of the aforementioned results. RESULTS: A total of 427 patients met inclusion criteria. After the index surgery, 155 patients (36%) underwent a routine imaging study. Among those with routine imaging, abnormalities were noted in 48 patients (31%); 7 went on to have reoperation (5%), and no malignant pathologies or torsion were identified. Excluding the 7 patients who went on to have a reoperation as a result of routine imaging, 113 patients developed symptoms postoperatively and underwent imaging as a result (27%, 113/420). Abnormalities were noted in 44 (10%); 15 of these patients underwent reoperation (4%), among them 2 with malignancies and 3 with torsion. Of these 44 patients, 23 had initially undergone routine imaging and subsequently went on to have symptomatic imaging, with 17% (4/23) undergoing reoperation. CONCLUSIONS: Routine imaging did not identify malignancy; most lesions identified on routine imaging were incidental findings. Although the study was not powered to appreciate a statistically significant difference, patients with malignancy or torsion were identified in the symptomatic group. This suggests no benefit from routine imaging, and supports symptomatic imaging postoperatively to minimize costs and patient/family burden.

EWS-FLI1 and Menin Converge to Regulate ATF4 Activity in Ewing Sarcoma.

Ewing sarcomas are driven by EWS-ETS fusions, most commonly EWS-FLI1, which promotes widespread metabolic reprogramming, including activation of serine biosynthesis. We previously reported that serine biosynthesis is also activated in Ewing sarcoma by the scaffolding protein menin through as yet undefined mechanisms. Here, we investigated whether EWS-FLI1 and/or menin orchestrate serine biosynthesis via modulation of ATF4, a stress-response gene that acts as a master transcriptional regulator of serine biosynthesis in other tumors. Our results show that in Ewing sarcoma, ATF4 levels are high and that ATF4 modulates transcription of core serine synthesis pathway (SSP) genes. Inhibition of either EWS-FLI1 or menin leads to loss of ATF4, and this is associated with diminished expression of SSP transcripts and proteins. We identified and validated an EWS-FLI1 binding site at the ATF4 promoter, indicating that the fusion can directly activate ATF4 transcription. In contrast, our results suggest that menin-dependent regulation of ATF4 is mediated by transcriptional and post-transcriptional mechanisms. Importantly, our data also reveal that the downregulation of SSP genes that occurs in the context of EWS-FLI1 or menin loss is indicative of broader inhibition of ATF4-dependent transcription. Moreover, we find that menin inhibition similarly leads to loss of ATF4 and the ATF4-dependent transcriptional signature in MLL-rearranged B-cell acute lymphoblastic leukemia, extending our findings to another cancer in which menin serves an oncogenic role. IMPLICATIONS: These studies provide new insights into metabolic reprogramming in Ewing sarcoma and also uncover a previously undescribed role for menin in the regulation of ATF4.

Wnt/ß-catenin-activated Ewing sarcoma cells promote the angiogenic switch.

Wnt/ß-catenin signaling is active in small subpopulations of Ewing sarcoma cells, and these cells display a more metastatic phenotype, in part due to antagonism of EWS-FLI1-dependent transcriptional activity. Importantly, these ß-catenin-activated Ewing sarcoma cells also alter secretion of extracellular matrix (ECM) proteins. We thus hypothesized that, in addition to cell-autonomous mechanisms, Wnt/ß-catenin-active tumor cells might contribute to disease progression by altering the tumor microenvironment (TME). Analysis of transcriptomic data from primary patient biopsies and from ß-catenin-active versus -nonactive tumor cells identified angiogenic switch genes as being highly and reproducibly upregulated in the context of ß-catenin activation. In addition, in silico and in vitro analyses, along with chorioallantoic membrane assays, demonstrated that ß-catenin-activated Ewing cells secreted factors that promote angiogenesis. In particular, activation of canonical Wnt signaling leads Ewing sarcoma cells to upregulate expression and secretion of proangiogenic ECM proteins, collectively termed the angiomatrix. Significantly, our data show that induction of the angiomatrix by Wnt-responsive tumor cells is indirect and is mediated by TGF-ß. Mechanistically, Wnt/ß-catenin signaling antagonizes EWS-FLI1-dependent repression of TGF-ß receptor type 2, thereby sensitizing tumor cells to TGF-ß ligands. Together, these findings suggest that Wnt/ß-catenin-active tumor cells can contribute to Ewing sarcoma progression by promoting angiogenesis in the local TME.

Microenvironmental Factors Drive Tenascin C and Src Cooperation to Promote Invadopodia Formation in Ewing Sarcoma.

Ewing sarcoma is a bone tumor most commonly diagnosed in adolescents and young adults. Survival for patients with recurrent or metastatic Ewing sarcoma is dismal and there is a dire need to better understand the mechanisms of cell metastasis specific to this disease. Our recent work demonstrated that microenvironmental stress leads to increased Ewing sarcoma cell invasion through Src activation. Additionally, we have shown that the matricellular protein tenascin C (TNC) promotes metastasis in Ewing sarcoma. A major role of both TNC and Src is mediation of cell-cell and cell-matrix interactions resulting in changes in cell motility, invasion, and adhesion. However, it remains largely unknown, if and how, TNC and Src are linked in these processes. We hypothesized that TNC is a positive regulator of invadopodia formation in Ewing sarcoma through its ability to activate Src. We demonstrate here that both tumor cell endogenous and exogenous TNC can enhance Src activation and invadopodia formation in Ewing sarcoma. We found that microenvironmental stress upregulates TNC expression and this is dampened with application of the Src inhibitor dasatinib, suggesting that TNC expression and Src activation cooperate to promote the invasive phenotype. This work reports the impact of stress-induced TNC expression on enhancing cell invadopodia formation, provides evidence for a feed forward loop between TNC and Src to promote cell metastatic behavior, and highlights a pathway by which microenvironment-driven TNC expression could be therapeutically targeted in Ewing sarcoma.

The Ewing Sarcoma Secretome and Its Response to Activation of Wnt/beta-catenin Signaling.

Tumor: tumor microenvironment (TME) interactions are critical for tumor progression and the composition and structure of the local extracellular matrix (ECM) are key determinants of tumor metastasis. We recently reported that activation of Wnt/beta-catenin signaling in Ewing sarcoma cells induces widespread transcriptional changes that are associated with acquisition of a metastatic tumor phenotype. Significantly, ECM protein-encoding genes were found to be enriched among Wnt/beta-catenin induced transcripts, leading us to hypothesize that activation of canonical Wnt signaling might induce changes in the Ewing sarcoma secretome. To address this hypothesis, conditioned media from Ewing sarcoma cell lines cultured in the presence or absence of Wnt3a was collected for proteomic analysis. Label-free mass spectrometry was used to identify and quantify differentially secreted proteins. We then used in silico databases to identify only proteins annotated as secreted. Comparison of the secretomes of two Ewing sarcoma cell lines revealed numerous shared proteins, as well as a degree of heterogeneity, in both basal and Wnt-stimulated conditions. Gene set enrichment analysis of secreted proteins revealed that Wnt stimulation reproducibly resulted in increased secretion of proteins involved in ECM organization, ECM receptor interactions, and collagen formation. In particular, Wnt-stimulated Ewing sarcoma cells up-regulated secretion of structural collagens, as well as matricellular proteins, such as the metastasis-associated protein, tenascin C (TNC). Interrogation of published databases confirmed reproducible correlations between Wnt/beta-catenin activation and TNC and COL1A1 expression in patient tumors. In summary, this first study of the Ewing sarcoma secretome reveals that Wnt/beta-catenin activated tumor cells upregulate secretion of ECM proteins. Such Wnt/beta-catenin mediated changes are likely to impact on tumor: TME interactions that contribute to metastatic progression.

A bivalent promoter contributes to stress-induced plasticity of CXCR4 in Ewing sarcoma.

Tumor heterogeneity is a major impediment to cancer cures. Tumor cell heterogeneity can arise by irreversible genetic mutation, as well as by non-mutational mechanisms, which can be reversibly modulated by the tumor microenvironment and the epigenome. We recently reported that the chemokine receptor CXCR4 is induced in Ewing sarcoma cells in response to microenvironmental stress. In the current study, we investigated plasticity of CXCR4 expression in vivo and assessed whether CXCR4 impacts on tumor growth. Our studies showed that Ewing sarcoma cells convert between CXCR4 negative and CXCR4 positive states in vivo and that positive cells are most abundant adjacent to areas of necrosis. In addition, tumor volumes directly correlated with CXCR4 expression supporting a role for CXCR4 in growth promotion. Mechanistically, our results show that, in ambient conditions where CXCR4 expression is low, the CXCR4 promoter exists in a poised, bivalent state with simultaneous enrichment of both activating (H3K4me3) and repressive (H3K27me3) post-translational histone modifications. In contrast, when exposed to stress, CXCR4 negative cells lose the H3K27me3 mark. This loss of promoter bivalency is associated with CXCR4 upregulation. These studies demonstrate that stress-dependent plasticity of CXCR4 is, in part, mediated by epigenetic plasticity and a bivalent promoter.

Promoter Methylation Analysis Reveals That KCNA5 Ion Channel Silencing Supports Ewing Sarcoma Cell Proliferation.

UNLABELLED: Polycomb proteins are essential regulators of gene expression in stem cells and development. They function to reversibly repress gene transcription via posttranslational modification of histones and chromatin compaction. In many human cancers, genes that are repressed by polycomb in stem cells are subject to more stable silencing via DNA methylation of promoter CpG islands. Ewing sarcoma is an aggressive bone and soft-tissue tumor that is characterized by overexpression of polycomb proteins. This study investigates the DNA methylation status of polycomb target gene promoters in Ewing sarcoma tumors and cell lines and observes that the promoters of differentiation genes are frequent targets of CpG-island DNA methylation. In addition, the promoters of ion channel genes are highly differentially methylated in Ewing sarcoma compared with nonmalignant adult tissues. Ion channels regulate a variety of biologic processes, including proliferation, and dysfunction of these channels contributes to tumor pathogenesis. In particular, reduced expression of the voltage-gated Kv1.5 channel has been implicated in tumor progression. These data show that DNA methylation of the KCNA5 promoter contributes to stable epigenetic silencing of the Kv1.5 channel. This epigenetic repression is reversed by exposure to the DNA methylation inhibitor decitabine, which inhibits Ewing sarcoma cell proliferation through mechanisms that include restoration of the Kv1.5 channel function. IMPLICATIONS: This study demonstrates that promoters of ion channels are aberrantly methylated in Ewing sarcoma and that epigenetic silencing of KCNA5 contributes to tumor cell proliferation, thus providing further evidence of the importance of ion channel dysregulation to tumorigenesis.

[Analysis of type 2 diabetes disease management: cross-study of a sanitary district]. / Analisi del disease management del diabete di tipo 2: uno studio trasversale su un distretto sanitario.

AIM: We studied type 2 diabetes prevalence in the Sicilian country, and the disease management, trough the analysis of some indicators. METHODS: A cohort of 385 subjects with type 2 diabetes was selected in a sanitary district. Anamnestic, anthropometric, pharmacological data were recorded by a self-controlled software (Gipac-2). We used Student's t-test for statistical data analysis. RESULTS: The cohort of diabetic people represents 3.97% of the studied population in toto, 206 women and 179 men: only 2/3 of the studied people followed the therapeutic indications, using prevalently oral hypoglycemic therapy, with poor agreement to specialised centres for diabetes. Hypertension was present in 52.51% of men, in 68.21% of women; most of 50% of people, men and women, showed an obesity/overweight condition. The observations of eventual diabetes complications (eye, foot etc.) was poor by doctors: a 1/3 of patients had diabetes complications undefined. The disease management analysis showed the use of antiplatelet-adhesion drugs involved a half of the studied people; 55-60% of people agreed to diet restriction, no sex-related; the self-control of glucose blood value was present in 65-70% of subjects. The indicators analysis showed that only 40% of men and women performed a HbA1C measurement; 40-50% of people did not control blood pressure in 90 days, 65% did not perform a LDL measurement in one year, more than 70% did not perform a fundus oculi check up. CONCLUSION: The study confirms the incidence of diabetes similar to national and European standards. The disease management appears lacunose in half of the population, the use of indicators is limited; guidelines on chronic disease management and on prevention of complications are partially applied. The use of sensitization strategies of sanitary operators, trough formation periods, is very important in order to implement the chronic disease management.

Mechanism of smectic arrangement of montmorillonite and bentonite clay platelets incorporated in gels of poly(acrylamide) induced by the interaction with cationic surfactants.

Structure transitions, induced by the interaction with the cationic surfactant cetylpyridinium chloride in nanocomposite gels of poly(acrylamide) with incorporated suspensions of the two closely related layered clays bentonite and montmorillonite, were studied. Unexpectedly, different behaviors were revealed. X-ray diffraction measurements confirm that, due to the interaction with the surfactant, initially disordered bentonite platelets arrange into highly ordered structures incorporating alternating clay platelets and surfactant bilayers. The formation of these smectic structures also in the cross-linked polymer gels, upon addition of the surfactant, is explained by the existence of preformed, poorly ordered aggregates of the clay platelets in the suspensions before the gel formation. In the case of montmorillonite, smectic ordering of the disordered platelets in the presence of the surfactant is observed only after drying the suspensions and the clay-gel composites. Rheology studies of aqueous suspensions of the two clays, in the absence of both surfactant and gel, evidence a much higher viscosity for bentonite than for montmorillonite, suggesting smaller clay-aggregate size in the latter case. Qualitatively consistent results are obtained from optical micrographs.

[New perspectives in the treatment of liver metastasis from colorectal cancer: radiofrequency thermal ablation]. / Nuove prospettive nel trattamento delle metastasi epatiche da cancro colorettale: la termoablazione mediante radiofrequenza.

Preliminary results of new treatment of metastatic hepatic malignancies from colo-rectal cancer, the radiofrequency ablation (RFA), are reported. The method is limited by few cases treated and short follow-up but it opens new perspectives in metasurgical treatment of these lesions as regards the previous experiences based on wide numbers of patients, recently reported in the literature.

Prognostic meaning of temporary clipping in patients with intracranial aneurysm.

The prognostic meaning of the routine use of the methods of temporary clipping of the afferent vessel in patients with intracranial aneurysm (Grading 0-III) was the aim of the analysis in this study. In the period 1 January, 1991-31 December 1997, 304 patients underwent surgery for non-giant intracranial aneurysm and a follow-up angiography. 157 patients were operated by routinely using the temporary clipping of the afferent vessel, whereas in 147 patients the surgical procedure was performed by traditional methods. The statistical analysis showed a significant reduction (p < 0.001) in terms of risk of surgical complications in the patients who underwent surgery with the temporary clip method compared to those operated with the traditional method, with a relative risk of such complications about three times greater in the latter. The routine use of temporary clipping offers, therefore, the possibility of a significant improvement of the surgical results, not influenced by a further involvement for the structure, due to the short application time.

Temporary clipping in the surgery of endocranial aneurysms.

The authors' experience in the routine use of temporary clipping procedures in the surgery of endocranial aneurysms is reported. To analyse the validity of such a method we compared the outcome in a series of 153 aneurysms operated according to the traditional procedure (temporary clipping of the afferent vessel only in the case of intraoperative rupture of the aneurysmatic sac) with that of a more recent series of 225 in which the procedure was applied routinely. An unsatisfactory surgical outcome was found in 12.5% and 6.6% of patients respectively, with a corresponding unfavourable outcome in 5.6% and 2.6%.