Magnetostriction-Driven Muon Localization in an Antiferromagnetic Oxide

Magnetostriction results from the coupling between magnetic and elastic degrees of freedom. Though it is associated with a relatively small energy, we show that it plays an important role in determining the site of an implanted muon, so that the energetically favorable site can switch on crossing a magnetic phase transition. This surprising effect is demonstrated in the cubic rocksalt antiferromagnet MnO which undergoes a magnetostriction-driven rhombohedral distortion at the Néel temperature T_{N}=118  K. Above T_{N}, the muon becomes delocalized around a network of equivalent sites, but below T_{N} the distortion lifts the degeneracy between these equivalent sites. Our first-principles simulations based on Hubbard-corrected density-functional theory and molecular dynamics are consistent with the experimental data and help to resolve a long-standing puzzle regarding muon data on MnO, as well as having wider applicability to other magnetic oxides.

Projectability disentanglement for accurate and automated electronic-structure Hamiltonians

Maximally-localized Wannier functions (MLWFs) are broadly used to characterize the electronic structure of materials. Generally, one can construct MLWFs describing isolated bands (e.g. valence bands of insulators) or entangled bands (e.g. valence and conduction bands of insulators, or metals). Obtaining accurate and compact MLWFs often requires chemical intuition and trial and error, a challenging step even for experienced researchers and a roadblock for high-throughput calculations. Here, we present an automated approach, projectability-disentangled Wannier functions (PDWFs), that constructs MLWFs spanning the occupied bands and their complement for the empty states, providing a tight-binding picture of optimized atomic orbitals in crystals. Key to the algorithm is a projectability measure for each Bloch state onto atomic orbitals, determining if that state should be kept identically, discarded, or mixed into the disentanglement. We showcase the accuracy on a test set of 200 materials, and the reliability by constructing 21,737 Wannier Hamiltonians.

Expansion of the Materials Cloud 2D Database

Two-dimensional (2D) materials are among the most promising candidates for beyond-silicon electronic, optoelectronic, and quantum computing applications. Recently, their recognized importance sparked a push to discover and characterize novel 2D materials. Within a few years, the number of experimentally exfoliated or synthesized 2D materials went from a few to more than a hundred, with the number of theoretically predicted compounds reaching a few thousand. In 2018 we first contributed to this effort with the identification of 1825 compounds that are either easily (1036) or potentially (789) exfoliable from experimentally known 3D compounds. Here, we report on a major expansion of this 2D portfolio thanks to the extension of the screening protocol to an additional experimental database (MPDS) as well as the updated versions of the two databases (ICSD and COD) used in our previous work. This expansion leads to the discovery of an additional 1252 monolayers, bringing the total to 3077 compounds and, notably, almost doubling the number of easily exfoliable materials to 2004. We optimize the structural properties of all these monolayers and explore their electronic structure with a particular emphasis on those rare large-bandgap 2D materials that could be precious in isolating 2D field-effect-transistor channels. Finally, for each material containing up to 6 atoms per unit cell, we identify the best candidates to form commensurate heterostructures, balancing requirements on supercell size and minimal strain.

Machine-learning accelerated identification of exfoliable two-dimensional materials

Two-dimensional (2D) materials have been a central focus of recent research because they host a variety of properties, making them attractive both for fundamental science and for applications. It is thus crucial to be able to identify accurately and efficiently if bulk three-dimensional (3D) materials are formed by layers held together by a weak binding energy that, thus, can be potentially exfoliated into 2D materials. In this work, we develop a machine-learning (ML) approach that, combined with a fast preliminary geometrical screening, is able to efficiently identify potentially exfoliable materials. Starting from a combination of descriptors for crystal structures, we work out a subset of them that are crucial for accurate predictions. Our final ML model, based on a random forest classifier, has a very high recall of 98%. Using a SHapely Additive exPlanations (SHAP) analysis, we also provide an intuitive explanation of the five most important variables of the model. Finally, we compare the performance of our best ML model with a deep neural network architecture using the same descriptors. To make our algorithms and models easily accessible, we publish an online tool on the Materials Cloud portal that only requires a bulk 3D crystal structure as input. Our tool thus provides a practical yet straightforward approach to assess whether any 3D compound can be exfoliated into 2D layers.

Shear and Breathing Modes of Layered Materials

Layered materials (LMs), such as graphite, hexagonal boron nitride, and transition-metal dichalcogenides, are at the center of an ever-increasing research effort, due to their scientific and technological relevance. Raman and infrared spectroscopies are accurate, non-destructive approaches to determine a wide range of properties, including the number of layers, N, and the strength of the interlayer interactions. We present a general approach to predict the complete spectroscopic fan diagrams, i.e., the relations between frequencies and N for the optically active shear and layer-breathing modes of any multilayer comprising N ≥ 2 identical layers. In order to achieve this, we combine a description of the normal modes in terms of a one-dimensional mechanical model, with symmetry arguments that describe the evolution of the point group as a function of N. Group theory is then used to identify which modes are Raman- and/or infrared-active, and to provide diagrams of the optically active modes for any stack composed of identical layers. We implement the method and algorithms in an open-source tool to assist researchers in the prediction and interpretation of such diagrams. Our work will underpin future efforts on Raman and infrared characterization of known, and yet not investigated, LMs.

OPTIMADE, an API for exchanging materials data

The Open Databases Integration for Materials Design (OPTIMADE) consortium has designed a universal application programming interface (API) to make materials databases accessible and interoperable. We outline the first stable release of the specification, v1.0, which is already supported by many leading databases and several software packages. We illustrate the advantages of the OPTIMADE API through worked examples on each of the public materials databases that support the full API specification.

Materials Cloud, a platform for open computational science

Materials Cloud is a platform designed to enable open and seamless sharing of resources for computational science, driven by applications in materials modelling. It hosts (1) archival and dissemination services for raw and curated data, together with their provenance graph, (2) modelling services and virtual machines, (3) tools for data analytics, and pre-/post-processing, and (4) educational materials. Data is citable and archived persistently, providing a comprehensive embodiment of entire simulation pipelines (calculations performed, codes used, data generated) in the form of graphs that allow retracing and reproducing any computed result. When an AiiDA database is shared on Materials Cloud, peers can browse the interconnected record of simulations, download individual files or the full database, and start their research from the results of the original authors. The infrastructure is agnostic to the specific simulation codes used and can support diverse applications in computational science that transcend its initial materials domain.

AiiDA 1.0, a scalable computational infrastructure for automated reproducible workflows and data provenance

The ever-growing availability of computing power and the sustained development of advanced computational methods have contributed much to recent scientific progress. These developments present new challenges driven by the sheer amount of calculations and data to manage. Next-generation exascale supercomputers will harden these challenges, such that automated and scalable solutions become crucial. In recent years, we have been developing AiiDA (aiida.net), a robust open-source high-throughput infrastructure addressing the challenges arising from the needs of automated workflow management and data provenance recording. Here, we introduce developments and capabilities required to reach sustained performance, with AiiDA supporting throughputs of tens of thousands processes/hour, while automatically preserving and storing the full data provenance in a relational database making it queryable and traversable, thus enabling high-performance data analytics. AiiDA's workflow language provides advanced automation, error handling features and a flexible plugin model to allow interfacing with external simulation software. The associated plugin registry enables seamless sharing of extensions, empowering a vibrant user community dedicated to making simulations more robust, user-friendly and reproducible.

Wannier90 as a community code: new features and applications

Wannier90 is an open-source computer program for calculating maximally-localised Wannier functions (MLWFs) from a set of Bloch states. It is interfaced to many widely used electronic-structure codes thanks to its independence from the basis sets representing these Bloch states. In the past few years the development of Wannier90 has transitioned to a community-driven model; this has resulted in a number of new developments that have been recently released in Wannier90 v3.0. In this article we describe these new functionalities, that include the implementation of new features for wannierisation and disentanglement (symmetry-adapted Wannier functions, selectively-localised Wannier functions, selected columns of the density matrix) and the ability to calculate new properties (shift currents and Berry-curvature dipole, and a new interface to many-body perturbation theory); performance improvements, including parallelisation of the core code; enhancements in functionality (support for spinor-valued Wannier functions, more accurate methods to interpolate quantities in the Brillouin zone); improved usability (improved plotting routines, integration with high-throughput automation frameworks), as well as the implementation of modern software engineering practices (unit testing, continuous integration, and automatic source-code documentation). These new features, capabilities, and code development model aim to further sustain and expand the community uptake and range of applicability, that nowadays spans complex and accurate dielectric, electronic, magnetic, optical, topological and transport properties of materials.

Valley-Engineering Mobilities in Two-Dimensional Materials

Two-dimensional materials are emerging as a promising platform for ultrathin channels in field-effect transistors. To this aim, novel high-mobility semiconductors need to be found or engineered. Although extrinsic mechanisms can in general be minimized by improving fabrication processes, the suppression of intrinsic scattering (driven, for example, by electron-phonon interactions) requires modification of the electronic or vibrational properties of the material. Because intervalley scattering critically affects mobilities, a powerful approach to enhance transport performance relies on engineering the valley structure. We show here the power of this strategy using uniaxial strain to lift degeneracies and suppress scattering into entire valleys, dramatically improving performance. This is shown in detail for arsenene, where a 2% strain stops scattering into four of the six valleys and leads to a 600% increase in mobility. The mechanism is general and can be applied to many other materials, including in particular the isostructural antimonene and blue phosphorene.

Delivery of selective internal radiation therapy complicated by variant hepatic vascular anatomy

“Difficult vascular anatomy” is a challenge for Interventional Radiologists especially in liver directed therapies such as trans arterial radio embolization.

Trans arterial radio embolization is a long and difficult procedure in which the basic knowledge of hepatic and gastro-enteric vascularization, with its high degree of variations, is very important in order to correctly administer the therapeutic drug selectively.

In this report, we present a case of an atypical patient affected by an unresectable hepatocellular carcinoma, candidate for Radio-embolization treatment.

His vascular anatomy was very difficult to manage, but the Interventional Radiologist was not only able to go over the “difficult anatomy,” but also to take advantage of it.

Osteoid osteoma treated with radiofrequency ablation in non-operating room anesthesia. A different way of approaching ablative therapy on osteoid osteoma

OBJECTIVE

The purpose of this study is to verify the effectiveness and complications occurrence of radiofrequency ablation (RFA) in the treatment of osteoid osteoma (OO) in non-operating room anesthesia (N.O.R.A.).

PATIENTS AND METHODS

From 2014 to 2017, 61 patients affected by OO (40 men and 21 women) with an age of 20.7 years on average (range, 4-51 years; 12 patients aged 20 years or younger) underwent computed tomography-guided percutaneous radiofrequency ablation (RFA) in N.O.R.A. (Non-Operating Room Anesthesia). Lesion sites treated were: femur (27), tibia (22), pelvis (2), talar bone (3), distal radius (1), and humerus (6). Mean follow-up time was 36 months. In each case, anesthesiologic support followed a new protocol (N.O.R.A. protocol), approved by our Institute. Primary success rate, complications, symptom-free intervals, and follow-up results were evaluated.

RESULTS

Pain relief (evaluated with Visual Analogue Scale - VAS) was significant in 97% of patients; it disappeared within 24 hours of the procedure in 44 patients, within 3 days in 10 patients, and within 7 days in 7 patients. After 6 months of observation time, 60 of 61 patients were successfully treated and had no more complaints. In 2 patients, two major complications were found: infection of the site treated, healed with antibiotics, and a nerve lesion, healed with steroid therapy. No other complications were observed.

CONCLUSIONS

RFA is a highly effective, efficient, minimally invasive and safe method for the treatment of OO following N.O.R.A.

PROTOCOL

Time Dependence of Hematoporphyrin Distribution in Selected Tissues of Normal Rats and in Ascites Hepatoma

The distribution of hematoporphyrin was determined in normal rats and in rats bearing ascites hepatoma as a function of time after i.p. injection of 10-20 mg/kg of dye. In both cases, hematoporphyrin displayed a high affinity for the tumor cells. At 20 mg/kg, the maximum difference between the amount of hematoporphyrin accumulated in the tumor and in the liver was obtained at 12 h after injection (tumor/liver ratio = 28). Our results suggest that hematoporphyrin is almost exclusively metabolized in the liver and excreted via the biliary tract, whereas only minor amounts are metabolized in the tumor cells. Moreover, the binding between the porphyrin and tumor cells is competitive with serum protein binding.

Two-dimensional materials from high-throughput computational exfoliation of experimentally known compounds

Two-dimensional (2D) materials have emerged as promising candidates for next-generation electronic and optoelectronic applications. Yet, only a few dozen 2D materials have been successfully synthesized or exfoliated. Here, we search for 2D materials that can be easily exfoliated from their parent compounds. Starting from 108,423 unique, experimentally known 3D compounds, we identify a subset of 5,619 compounds that appear layered according to robust geometric and bonding criteria. High-throughput calculations using van der Waals density functional theory, validated against experimental structural data and calculated random phase approximation binding energies, further allowed the identification of 1,825 compounds that are either easily or potentially exfoliable. In particular, the subset of 1,036 easily exfoliable cases provides novel structural prototypes and simple ternary compounds as well as a large portfolio of materials to search from for optimal properties. For a subset of 258 compounds, we explore vibrational, electronic, magnetic and topological properties, identifying 56 ferromagnetic and antiferromagnetic systems, including half-metals and half-semiconductors.

A posteriori metadata from automated provenance tracking: integration of AiiDA and TCOD

In order to make results of computational scientific research findable, accessible, interoperable and re-usable, it is necessary to decorate them with standardised metadata. However, there are a number of technical and practical challenges that make this process difficult to achieve in practice. Here the implementation of a protocol is presented to tag crystal structures with their computed properties, without the need of human intervention to curate the data. This protocol leverages the capabilities of AiiDA, an open-source platform to manage and automate scientific computational workflows, and the TCOD, an open-access database storing computed materials properties using a well-defined and exhaustive ontology. Based on these, the complete procedure to deposit computed data in the TCOD database is automated. All relevant metadata are extracted from the full provenance information that AiiDA tracks and stores automatically while managing the calculations. Such a protocol also enables reproducibility of scientific data in the field of computational materials science. As a proof of concept, the AiiDA–TCOD interface is used to deposit 170 theoretical structures together with their computed properties and their full provenance graphs, consisting in over 4600 AiiDA nodes.

Performance of arsenene and antimonene double-gate MOSFETs from first principles

In the race towards high-performance ultra-scaled devices, two-dimensional materials offer an alternative paradigm thanks to their atomic thickness suppressing short-channel effects. It is thus urgent to study the most promising candidates in realistic configurations, and here we present detailed multiscale simulations of field-effect transistors based on arsenene and antimonene monolayers as channels. The accuracy of first-principles approaches in describing electronic properties is combined with the efficiency of tight-binding Hamiltonians based on maximally localized Wannier functions to compute the transport properties of the devices. These simulations provide for the first time estimates on the upper limits for the electron and hole mobilities in the Takagi's approximation, including spin-orbit and multi-valley effects, and demonstrate that ultra-scaled devices in the sub-10-nm scale show a performance that is compliant with industry requirements.

Limb saving procedure in metastatic leiomyosarcoma of the femoral vein: case report and literature review

Primary venous leiomyosarcoma is very rare and first description was made by Perl in 1871. Most cases are from venous system and half of them are reported to originate in inferior vena cava. We report the case of a 77-year-old Caucasian man with a leiomyosarcoma of the femoral vein. A leg preservation surgery was decided. Eight months later, the patient died of tumor progression. A PubMed search using the terms "leiomyosarcoma femoral vein" and "leiomyosarcoma vein" was performed. All cases of composite iliac-femoral leiomyosarcoma were excluded, and as far as possible, only well-documented cases were included. Median age was 55 years, seven men and six women, tumor resection was performed by six authors, six others performed a vascular resection, and one preferred for a thigh excision. Prognosis remains poor if metastasis is present, and in these cases, a conservative surgery is recommended to preserve patients' quality of life.

Multi-centre phase II clinical trial of yttrium-90 resin microspheres alone in unresectable, chemotherapy refractory colorectal liver metastases

BACKGROUND

This multi-centre phase II clinical trial is the first prospective evaluation of radioembolisation of patients with colorectal liver metastases (mCRC) who failed previous oxaliplatin- and irinotecan-based systemic chemotherapy regimens.

METHODS

Eligible patients had adequate hepatic, haemopoietic and renal function, and an absence of major hepatic vascular anomalies and hepato-pulmonary shunting. Gastroduodenal and right gastric arteries were embolised before hepatic arterial administration of yttrium-90 resin microspheres (median activity, 1.7 GBq; range, 0.9-2.2).

RESULTS

Of 50 eligible patients, 38 (76%) had received > or =4 lines of chemotherapy. Most presented with synchronous disease (72%), >4 hepatic metastases (58%), 25-50% replacement of total liver volume (60%) and bilateral spread (70%). Early and intermediate (>48 h) WHO G1-2 adverse events (mostly fever and pain) were observed in 16 and 22% of patients respectively. Two died due to renal failure at 40 days or liver failure at 60 days respectively. By intention-to-treat analysis using Response Evaluation Criteria in Solid Tumours, 1 patient (2%) had a complete response, 11 (22%) partial response, 12 (24%) stable disease, 22 (44%) progressive disease; 4 (8%) were non-evaluable. Median overall survival was 12.6 months (95% CI, 7.0-18.3); 2-year survival was 19.6%.

CONCLUSION

Radioembolisation produced meaningful response and disease stabilisation in patients with advanced, unresectable and chemorefractory mCRC.

Lycopersicon esculentum lectin is a marker of transient amplifying cells in in vitro cultures of isolated limbal stem cells

The maintenance of a healthy corneal epithelium under both normal and wound healing conditions is achieved by a population of stem cells (SCs) located in the basal epithelium at the corneoscleral limbus. In the light of the development of strategies for reconstruction of the ocular surface in patients with limbal stem cell deficiency, a major challenge in corneal SCs biology remains the ability to identify stem cells in situ and in vitro. To date, not so much markers exist for the identification of different phenotypes. CESCs (corneal epithelial stem cells) isolated from limbal biopsies were maintained in primary culture for 14 days and stained with Hoechst and a panel of FITC-conjugated lectins. All lectins, with the exception of Lycopersicon esculentum, labelled CESCs irrespective of the degree of differentiation. Lycopersicon esculentum, that binds N-acetylglucosamine oligomers, labelled intensely only the surface of TACs (single corneal epithelial stem cells better than colonial cells). These results suggest that Lycopersicon esculentum lectin is a useful and easy-to-use marker for the in vitro identification of TACs (transient amplifying cells) in cultures of isolated CESCs.

Tight-binding calculation of optical gain in tensile strained [001]-Ge/SiGe quantum wells

It is known that under a tensile strain of about 2% of the lattice constant, the energy of the bottom conduction state of bulk Ge at the Gamma point falls below the minimum at the L point, leading to a direct gap material. In this paper we investigate how the same condition is realized in tensile strained Ge quantum wells. By means of a tight-binding sp(3)d(5)s(*) model, we study tensile strained Ge/Si(0.2)Ge(0.8) multiple quantum well (MQW) heterostructures grown on a relaxed SiGeSn alloy buffer along the [001] direction. We focus on values of the strain fields at the crossover between the indirect and direct gap regime of the MQWs, and calculate band edge alignments, electronic band structures, and density of states. We also provide a numerical evaluation of the MQW material gain spectra for TE and TM polarization under realistic carrier injection levels, taking into account the leakages related to the occupation of the electronic states at the L point. The analysis of the different orbital contributions to the near-gap states of the complete structure allows us to give a clear interpretation of the numerical results for the strain-dependent TM/TE gain ratio. Our calculations demonstrate the effectiveness of the structures under consideration for light amplification.

Modifications of nuclear envelope in tumour cells of human gastric carcinomas: an ultrastructural study

BACKGROUND

Various nuclear envelope derivatives, such as the annulate lamellae, the intranuclear tubules as well as the nuclear projections and pockets may be observed electron microscopically in tumour cells.

PATIENTS AND METHODS

In a series of eight gastric adenocarcinomas, ultrastructural features of nuclear envelope changes were analyzed and correlated to the biology of the tumours.

RESULTS

Histologically, three tumours were intestinal-type adenocarcinomas and showed annulate lamellae in the cytoplasm of some tumor cells. Five tumors were mixed-type adenocarcinomas, with a solid growth pattern; two of these tumours were characterized by the presence of intranuclear tubules, whereas the remaining three tumours exhibited nuclear pockets and projections. Seven out of eight patients died due to metastatic disease during the follow-up period (median 31 months).

CONCLUSION

Ultrastructural evaluation of pleomorphism of the nuclear envelope may be an ancillary method for the pathologist in the study of nuclear grading of gastric carcinomas.

Granulomatous inflammatory reaction in human gastric adenocarcinomas: a light and electron microscopy study

Granuloma is a focal, compact collection of inflammatory cells in which mononuclear phagocytes predominate. The authors report 9 cases of papillary-tubular gastric adenocarcinomas characterized by mature granulomas associated with recent microhemorrhages. Mature granulomas were composed of foamy, CD68-positive histiocytes with occasional giant cells. Hemosiderin-containing macrophages were present in the tumor stroma, suggesting phagocytosis of erythrocytes. Under electron microscopy, mature (nonepithelioid) granulomas and clusters containing 1 macrophage and 1-3 eosinophils were found. This study provides morphological examples of skewed type II macrophage infiltration in gastric adenocarcinomas that is involved in scavenging activity, particularly erythrophagocytosis, formation of mature (nonepithelioid granulomas), and heterotypic aggregation with eosinophils.

POCHER (preoperative chemotherapy for hepatic resection) with cetuximab (Cmab) plus CPT-11/5-fluorouracil (5-FU)/leucovorin(FA)/oxaliplatin (L-OHP) (CPT-11-FFL) in unresectable colorectal liver metastases (CLM)

e15020

Background: We have previously shown preliminary data with Cmab+ all active drugs, CPT-FFL, with primary end- point CLM resectability (Garufi C. et al ASCO GI 2008). Here we report definitive clinical results. Methods: Unresectability criteria: size>5 cm (a), multinodular (b), ilar location (c), extrahepatic disease (d), >3 stable mets after chemotherapy before surgery (e). Aim of the study was to have at least 30% liver resection rate (power of 80% for p0=10% and p1=25%). Pts received weekly Cmab 400 then 250 mg/m2/wk plus CPT-11, 130 mg/m2/d1, 6 h infusion, (peak at 13:00) and a 12-h, days 2–5, infusion of L-OHP 20 mg/m2/day (peak at 16:00), FA 150 mg/m2/day plus 5-FU 600 mg/m2/d (peak at 4:00), q 2 wks; after the first 17 pts 5-FU and L-OHP were reduced to 550 and 15 mg/m2 respectively. Results: Since 07/20/2006 we enrolled 43 pts, irrespective of EGFR, K-ras and gene copy number (gcn): M/F 27/16, median age 60,7 y (33–76), median PS 0. Primary tumor: colon/rectum 34/9, primary tumor resected 39 pts (79%), synchronous metastases: 35 pts (81%), liver <25%/25%: 9/34 ((21/79%); median CEA/CA19–9: 55 ng/ml (1–6,600)/91.8 U/L (2.66440); unresectability: (a): 9 (21%), (b):14 (33%), (c) 1, (d): 4 (9%), (e): 15 (35%). We had 34 partial responses (79%, CI 79.1–87.0), 5 SD (11.6%) and 4 patients not evaluable becouse of toxicity. Complete Resection of CLM was obtained in 27 pts (63%) with 4 pts still to be resected. Median number (n.) of courses (c) was 10 (2–18), median n. of c before surgery (s) was 5 (3–10) and after s was 6 (1–6); median time from last c to s was 2 wks (2–4), from s to recovery chemo was 10 wks (2–16). Median follow-up was12 months, median PFS 13 months (7–19), median OS not reached with 2-y survival of 61%, 8 pts alive without recurrence (19%), 11 deaths (25%).Major limiting toxicity was diarrhea, with no difference after dose reduction: Grade 0–1: 6% of pts, G2 6%, G3 76%, G4 12%; neutropenia G3 6% with no febrile neutropenia. Conclusions: This is the first phase II study with CPT-FFL + Cmab in pts with unresectable CLM. Complete resection was obtained in 63% of pts with diarrhea being limiting toxicity. Analysis of EGFR status, K-ras and gcn will be further presented.

No significant financial relationships to disclose.

Ultrastructural descriptions of pericyte/endothelium peg-socket interdigitations in the microvasculature of human gastric carcinomas

BACKGROUND

Angiogenesis requires complex multistep signalling pathways and a high degree of spatial and temporal coordination among endothelial cells and pericytes. The two cell types exhibit numerous contacts in vivo and in vitro, including the occurrence of peg-socket junctions.

MATERIALS AND METHODS

Ultrastructural findings in 9 cases of advanced gastric carcinomas were reviewed with special emphasis on endothelium/pericyte peg-socket junctions.

RESULTS

The incidence of peg-socket junctions was approximately 8% in 5 out of 9 cases. The remaining 4 cases showed a very low rate, including two cases in whom interactions were totally absent. Peg-socket junctions consisted of cytoplasmic projection from the pericyte protruding into the endothelial indentation. The endothelial cells interacting with pericytes showed ultrastructural signs of partial stabilization such as continuous endothelial lining, regularly constructed interendothelial junctions, more or less integrated pericytes, and multilayered basement membrane.

CONCLUSION

Our ultrastructural study confirms previous reports regarding pericyte/endothelial peg-socket interdigitations in murine and human granulation tissues and extends these findings to the microvasculature of human gastric carcinomas.

Percutaneous vesiculodeferentography in the diagnosis of male infertility: A review of our results and the data reported in the literature

Vesiculodeferentography was used in the past to evaluate suspected cases of obstruction of the seminal ducts. Over the years, numerous attempts have been made to improve the technique used to perform this examination and to render it less invasive. Its use is currently indicated in selected cases, where it is combined with functional studies like seminal tract washout and followed by immediate interventions to correct the alterations revealed. Vesiculodeferentography includes collection of the contents of the seminal vesicles, which can later be used in vitro assisted fertilization procedures.

Sonographic features of penile-gland lithiasis

A 52-year-old man presented with a small, red, tender swelling near the penile frenulum at the lower edge of the base of the glans. Lower urinary tract symptoms were absent. Ultrasonography revealed a stone lodged in the distalmost portion of the glands of Littre. Combined with a good knowledge of penile anatomy, use of this simple imaging tool allows reliable diagnosis of even the rarest cases of penile pathology.

Krukenberg tumour of the ovary: a case report with light microscopy, immunohistochemistry and electron microscopy study

A rare case of a 46-year-old woman with bilateral Krukenberg tumours is reported. Histologically, oedematous ovarian stroma was infiltrated by signet-ring cells arranged singly, in cords or in nests. Immunoreactivity for cytokeratin-7, carcinoembryonic antigen as well as histochemical positivity for mucins demonstrated the epithelial nature of the tumour. The gastric primary site was suggested by the cytoplasmic immunoreactivity for MUC-5AC and by ultrastructural evidence of gastric differentiation in signet-ring cells such as mucous granules with eccentric dense cores and intracellular microcysts, lined by sparse microvilli. Gastric biopsy, performed after pathological diagnosis, revealed a signet-ring cell carcinoma similar to that in the ovaries, confirming the gastric origin of the Krukenberg tumour. Because none of the individual immunohistochemical markers used for tissue identification is both site specific and site sensitive, electron microscopy in combination with immunohistochemistry is a valuable tool for the pathologist in the diagnosis of the tissue origin of a Krukenberg tumour.

A multicentric phase II clinical trial on intra-arterial hepatic radiotherapy with 90yttrium SIR-spheres in unresectable, colorectal liver metastases refractory to i.v. chemotherapy: preliminary results on toxicity and response rates

BACKGROUND

In patients locally progressing after two lines of chemotherapy, some locoregional approaches showed encouraging results in terms of local control of disease. The aim of our study was to evaluate toxicity, clinical response and quality of life in 48 patients with unresectable colorectal liver metastases submitted to selective internal radiotherapy (SIRT).

MATERIALS AND METHODS

Up to now 35 patients with unresectable colorectal liver metastases, refractory to two lines of chemotherapy, underwent intra-arterial infusion of resin microspheres with yttrium-90 (SIR-spheres). Pre-treatment evaluation included a CT scan, blood tests, a PET scan and arteriography of celiac trunk, hepatic and superior mesenteric artery; extrahepatic uptakes and pulmonary shunts more than 10% were excluded by a Scinti-scan. The gastroduodenal artery was embolized before the SIR-spheres injection. Other exclusion criteria were liver dysfunction and anatomical vascular anomalies. The clinical response was evaluated by CT-scan following the RECIST criteria. Median follow-up was 4 months.

RESULTS

Median number of metastases was 4 (range, 1-15), 38% of cases presenting hepatic involvement < 25%. The median SIRT dose delivered was 1.7 GBq. Median pulmonary shunt was 6%. No operative mortality occurred; early toxicity (within 48 hours) was 20.6%, shown as fever, acute pain and leucocytosis. The late toxicity was 24.1% with chronic pain, jaundice and nausea being the most frequent. All the toxic events were graded 2 or 3 according to the WHO scale. Preliminary results were available in terms of clinical response after 6 weeks: 12.5% had a partial response, 75% a stable disease, while progression of disease, was observed in 12.5% of the patients.

CONCLUSION

SIRT is a safe treatment in terms of acute and late toxicity. Intra-arterial microspheres could represent a good therapeutic option for patients with progressing liver metastases only, after two lines of systemic chemotherapy.

5-year prospective results of trimodality treatment for malignant pleural mesothelioma

AIM

Even though followed by a prolonged survival in highly selected patients, the promising results of Sugarbaker's trimodality treatment for malignant pleural mesothelioma (MPM) are debated and not yet uniformly replicated. The purpose of this study is to evaluate prospectively the reproducibility of the trimodality treatment results in a patient population with mesothelioma staged by the IMIG classification.

METHODS

Fifty-four patients with MPM have been judged candidable to extended pleuropneumonectomy (EPP), to be followed by chemotherapy (paclitaxel+carboplatin) and radiotherapy (50 Gy).

RESULTS

At thoracotomy, 44 of the 54 surgical candidates (81%) underwent EPP; 73% of the operated patients completed the entire adjuvant chemo-radiotherapy with no major toxicity. The 30-day or in-hospital operative mortality rate was 4.5% (2 deaths), the major morbidity 36%, and the overall complication rate 50%. At 5 years the projected survival of the 42 surgical survivors submitted to EPP is 19%; median survival is 20 months. The restricted group of patients with epithelial, N0-1, completely resected MPM (microscopic negative margins) exhibits a projected 50% 5-year survival. Clinical understaging has shown up to be noticeable both at the thoracotomy exploration and pathology examination. Most of the disease recurrences are loco-regional and the current insufficiency of intraoperative or postsurgical radicality needs improvement, along with earlier diagnosis, more accurate staging, and preoperative induction for the multimodality treatment of pleural mesothelioma to become an established curative option.

CONCLUSIONS

This series confirms the reproducibility of the trimodality treatment for MPM,which is associated with prolonged survival for early-stage tumors at the cost of a not prohibitive treatment-related mortality rate.

[Radiotherapy of the tonsillar region. Analysis of prognostic factors]

INTRODUCTION

We report our personal experience with the treatment of tonsillar cancers at the Otorhinolaryngology-Radiotherapy Department of Umberto I Hospital, Mestre, Italy. The results were analyzed by tumor site and stage, lymph node involvement, treatment type and patient age.

MATERIAL AND METHODS

January, 1987, through December, 1995, we treated a hundred and 25 patients with carcinoma of the tonsil and tonsillar region. Most patients were men (M:F = 4:1), with a mean age of 61.9 years (range: 38-87). The lesions were staged at physical examination, chest radiography, bone scintigraphy. US of the liver and neck, CT and/or MRI of the tonsillar region and neck. Eleven patients were in stage I (8.8%), 26 in stage II (20.8%), 31 in stage III (24.8%) and 57 in stage IV (45.6%). Forty-one patients were submitted to tonsillectomy and more/less massive neck dissection: surgery was not radical-in 14 of them. All patients received gamma-photon radiotherapy with a cobalt unit: the minimum dose was 50 Gy after radical surgery and 60 Gy for exclusive irradiation and after nonradical surgery. The hemiblock field technique was always used with the conventional fractionation (2 Gy/day. 1 fraction/day, 5 fractions/week); the treatment was planned with the Theraplan V05-B method on CT scans. When the tolerance dose was reached, the spinal cord was shielded and the dose compensated with 9 MeV electrons. The treatment was discontinued only when needed, and never for more than 7-10 days.

RESULTS

The overall 5-year survival and the 5-year disease-free survival rates were 28% and 45%, respectively; the overall 5-year cause-specific survival rate was 39%. Disease-free survival was 81% in stage I, 52.7% in stage II, 44.2% in stage III and 35.8% in stage IV (p = .005). The 5-year disease-free survival for the patients receiving surgery and irradiation was 62.1%, versus 38.3% for irradiation alone; the rate was 37.6% when neck nodes were involved (N+). One hundred and two patients achieved complete remission (CR), while the other 23 had partial remission (PR). Twenty-eight CR patients recurred; the most common cause of death was failure in primary tumor local control. There were no complications during or after treatment. Secondary lesions were found in 13 patients (10.1%).

CONCLUSIONS

Irradiation alone yields fairly good results in early tonsil carcinoma, while the surgery-irradiation combination should be preferred in large tumors. Better results are expected from kinetic and conformal irradiation techniques with 3D calculations on CT and MR images, which should permit to deliver high doses to strictly targeted areas and to reduce side-effects. Other improvements are expected from new combination therapies.

Radiotherapy in Treating Bladder Cancer

The author reports his experience in the Radiotherapy Unit of the Hospital of Mestre with regard to 270 cases of infiltrating bladder cancer treated with just RT or in combination with chemotherapy. The indication for radiotherapy is examined according to the stage of the disease, taking into account the toxic effects following such treatment. In conclusion the author recommends closer cooperation between specialisations to provide a more effective and tolerable treatment of the disease.

Self-expanding stents in transjugular intrahepatic portosystemic shunt: experience with nitinol Strecker stents

The aim of our study was to evaluate the performance and efficacy of a new self-expanding stent (nitinol Strecker stent) in the transjugular intrahepatic portosystemic shunt (TIPS) procedure. We have successfully placed 64 nitinol Strecker stents in 48 patients. The average portosystemic gradient decreased from 22 to 11 mm Hg. Balloon dilatation was necessary in 12 of 35 angiographically controlled cases at 5 days (34%), because of incomplete stent expansion, small thrombi within the stent or obstruction. At 1-6 months stent malfunctions occurred in 8 of 23 patients who underwent control angiography (34%) and at 6-24 months in 6 of 7 patients (85%). Rebleeding occurred in 2 of 39 patients (follow-up > 1 month) (5%) and temporary crises of de novo encephalopathy were observed in 11 of 48 patients (23%). Refractory ascites completely resolved in 4 of 6 patients (66%) and improved in the remaining 2 cases. Compared with other self-expanding stents, nitinol Strecker stents seem to be equally effective in TIPS; no increase in complication rate was observed, either clinical or stent-related.

[The use of a single anterior oblique field in the treatment of T1aN0 vocal cord neoplasms. Results and comparison with other technics]

From 1985 through 1993, 113 patients affected with T1N0 glottic cancer were treated with irradiation alone at the Radiotherapy Department of Umberto I Hospital in Mestre, Italy. An anterior oblique beam of 12 MV X-rays (LINAC) or gamma-rays of a Cobalt unit were used. Dose distribution was always studied on CT scans and with a Theraplan V05-B, Theratronics. Patients age ranged 40-92 years (mean: 64.7 years) and they were mostly males. The dose was always 60 Gy/30 fractions referred to the 90% isodose. The dose to the target volume ranged 90-105%, with a mean of 99%. The follow-up ranged 26 to 98 months; the median and the mean are 38 and 40 months, respectively. Six patients had local relapses and were all operated on: cordectomy was performed in 3 of them and laryngectomy in the other 3. Radiation therapy yielded 94.7% disease control; the lesion was ultimately controlled in 100% of patients after surgical salvage. Fifteen patients died, all of them of non-neoplastic disease. The authors compared this technique with those most frequently used, i.e., wedged opposed lateral fields and wedged anterior oblique beams, and observed that it allows minimal volumes to be irradiated with maximal doses and yields results. Wedged beams are not necessary with this technique. The authors consider irradiation the treatment of choice for early glottic cancer and believe that surgery, with the conservative approach if feasible, should be limited to relapses.

[The polycentric multiple arc complanar technic, or telebrachytherapy. A 4-year experience (an innovative way for the local control of solid neoplasms)]

The coplanar polycentric multiple 180 degrees single arc and narrow beams technique (PMA) allows high radiation doses to be delivered to the target, with similar dose distribution to that of brachytherapy. Since 1990, more than 100 patients have been treated: 80 had NSCLC, 12 had epidermoid head and neck (oral cavity and oropharynx) cancers, 8 brain tumors, 4 esophageal cancers and, sporadically, other patients had many other kinds of tumors, e.g., Hodgkin's and non-Hodgkin's lymphomas and sarcomas. X photons of a 12-MV Linac have always been used. NSCLC patients are assessable for local control, toxicity and survival, while the other patients only for local control and/or toxicity. As for 31 stage I-II lung cancer patients, CR has been observed in 82.8% of them and PR in 13.8%; the response was always assessed with chest radiography, CT, FBS, cytology and/or histology. The overall actuarial survival rate is 71% at 40 months, the disease-free survival rate is 75% and the local progression-free survival rate is 94%. As for 49 stage-III patients, CR has been observed in 40% of them and PR in 56%. The overall disease-free survival is 10% at 28 months (median survival: 14.37 +/- 0.6 months). The disease-free survival rate is 23%. The local progression-free survival rate is similar to the overall survival rate, which seems to prove the very high metastatic spread of this disease in advanced stages. Twelve head and neck cancer patients have been treated, 5 of them in stage II and 7 in stage IV. CR has been observed in all the patients in lower stages (100%), in 4/7 patients in stage IV (57%) and in 4/5 patients (80%) in the T4N0 subgroup. The response of brain tumors treated with the PMA technique is difficult to assess because radiographic, CT and MR images are difficult to correlate with patients clinical status. The patients in our series are still alive, with a medium follow-up of 7 months (range: 2-16 months). A longer follow-up is necessary before any other considerations on the effectiveness of this method can be made. This technique was used on the patients who were not eligible for the other techniques with high doses delivered to the tumor, because of its volume and/or shape. Four esophageal cancers were treated with palliative intent, because of absolute dysphagia, in alternative to HDR brachytherapy. All these patients have obtained symptom remission.(ABSTRACT TRUNCATED AT 400 WORDS)

[Brachytherapy of epistaxis in Rendu-Osler disease. Indications, technic, results]

Rendu-Osler disease is a clinical form characterized by skin, mucous and bowel teleangiectasias causing repeated bleeding, especially in the nasal region. Repeated epistaxis is controlled, however transiently, with electrocoagulation, laser therapy, embolization, mucous transplants and external radiotherapy or, more frequently, brachytherapy. The authors report on a Curietherapy technique based on the use of 192Iridium wires. The wires, which cannot be placed in parallel lines, must be positioned in three places after a fan-wise pattern: the first one on the floor, the second one along the anterior wall and the third one in between. The three wires are inserted into plastic tubes during fluoroscopy. The length of the wires is differentiated for greater dose distribution homogeneity. The dose given to the reference isodose--which is probably in contact with the mucosa--is 30 Gy. We performed 9 maneuvers in 6 patients and three of them were also treated in the contralateral nostril. Complete remission was seen in 4 patients. In 2 patients the response has lasted 18 and 32 months and 2 others have a shorter follow-up. In 5 patients we obtained a good response (mean: 58 months). Our results are in agreement with those in brachytherapy literature. Few trials are reported of external irradiation but in our personal experience, its results are poor. Brachytherapy effect is limited in time but yields major clinical benefits to the patient. Brachytherapy cannot replace other treatment methods and must therefore be considered as a palliative treatment which can improve patient's quality of life in time.

[Carcinoma in situ of the breast: which treatment?]

From January 1984 to December 1992, twenty-eight patients affected with breast carcinoma in situ were treated with surgery (8 with radical mastectomy, 20 with quadrantectomy) at Umberto I Hospital in Mestre, Italy. The patients with multicentric lesions and treated with quadrantectomy received also radiation therapy. The dose was 50 Gy/25 fractions with 60Co and a boost of 10 Gy to the tumor bed. The mean age of our patients was 55 years (range: 34-74 years). Histology diagnosed lobular carcinoma in situ in 7 cases, intraductal carcinoma in 19 cases and comedocarcinoma in 2 cases. The median and the mean follow-up are 37 and 42 months (range: 24-128), respectively. The eight-year local control and the cause-specific survival rates are 100%. No local relapses have been observed. One patient died, of another neoplastic disease, free from breast disease. We believe that the conservative approach in breast carcinoma in situ, according to literature results and to our personal experience, should be more frequently preferred to radical surgery even in the patients with multicentric lesions.

[Transjugular intrahepatic porto-systemic shunt (TIPS): indications and results]

This study was aimed at describing some technical features of the transjugular portosystemic shunt (TIPS). December 1991 to November 1993, fifty-five TIPS were performed in our department. The right internal jugular vein, which is the most direct path to the inferior vena cava, was punctured in 48 cases, the left one in seven cases. The right suprahepatic vein was catheterized in 43 cases, and the median suprahepatic vein in 12 cases. The puncture of the portal vein was performed in 21 cases in the right portal branch, in the left one in 23 cases, and in the portal bifurcation in 11 cases. In all cases in which the puncture site was questionable, an X-ray exam with lateral or oblique projection was performed, to be sure that the needle had entered the intrahepatic portion of the portal vein. A landmark to locate the portal system, such as a catheter in the hepatic artery, a skin landmark or a metallic coil near the porta, were positioned in 30 patients. Particularly, in 20 patients, a 0.018-inch guidewire with platinum tip was placed at the bifurcation; in seven cases a 3F catheter was advanced over the guidewire, to visualize the portal bifurcation directly with contrast medium injection. In our experience, a total number of 83 stents were positioned in 55 patients: 53 Wallstents, 13 Palmaz stents, and 17 Strecker-Nitinol stents. One single stent was placed in 31 patients, two stents in 21 patients, three stents in two patients, and, finally, four stents were positioned in one patient. In our series the technical success rate was 100%. The use of a metallic landmark significantly decreased procedures duration, ranging 40 minutes to 2 hours, and, above all, it allowed for significantly fewer puncture attempts, which varied from a minimum of 1-2 in 80% of cases, to a maximum of 20 especially in these patients with ascitis and with small and hard liver.

[The role of ultrasonography in thyroid disease]

Ultrasound examination of the thyroid gland is widely used in the diagnosis of thyroid disease. This test is easy and rapid to perform, widely available and the results are readily interpreted. Using ultrasound the image of foci of disease within the gland are easily identified, especially using high frequency probes which enable solid nodules up to approx 3 mm to be revealed with 10 MHz probes. In non-nodular thyroid disease the ultrasonic structure guides the diagnosis (thyroiditis, Graves' disease). During the follow-up of thyroidectomised patients ultrasound can easily reveal postoperative anatomic variations and an early diagnosis can be obtained of any signs of local recurrence of the primary disease. Only hemiagenesia and hypoplasia can be accurately evaluated in congenital disease, whereas in the event of the persistence of the thyroglossal duct the latter can only be diagnosed if it presents a cystic evolution. Thyroid ectopia cannot be identified and must be studied using thyroscintigraphy, preferably performed using 131I as the isotope. The acquired pathology is classified into phlogistic processes, diffuse or nodular hyperplasia, benign and malignant neoplasia. This classification is widely accepted by virtually all authors. In thyroiditis, ultrasound may facilitate the diagnosis of De Quervain's non-suppurative sub-acute thyroiditis (TANS) and Hashimoto's chronic thyroiditis, although always in association with clinical and laboratory tests. The most frequent thyroid pathology is without doubt goitre. This disorder may occur in a non-nodular (widespread goitre with an endemic or sporadic pattern) or nodular form which may be single or multiple. The term goitre is used to indicate the increased volume of the thyroid gland independently of the causes which have provoked it. Common goitre is defined as being endemic when in some geographic area 10% of the general population or 20% of the school-aged population suffers from thyroid hyperplasia (areas of goitrogenic endemic disease). Graves' disease may be included in the group of thyroid hyperplasia diseases, although it is distinguished from the simple versions by the marked glandular hyperactivity which creates manifest hyperthyroidism. In this pathology ultrasonography must be supplemented by colour-Doppler wherever possible. Thyroid nodules are subdivided in terms of their echostructure into 5 types: liquid, mixed (prevalently solid or prevalently liquid), hyperechogenic solid, isoechogenic solid and hypoechogenic solid. The characteristics of benign nodules are: hypoechogenic structure, regular edges, complete and uniform hypoechogenic peripheral halo.(ABSTRACT TRUNCATED AT 400 WORDS)

[Percutaneous treatment of symptomatic renal cysts: effects of the combination of sclerotherapy with alcohol and fibrin glue (tissucol)]

The percutaneous treatment of symptomatic renal cysts has grown in therapeutic importance over the last years. The international literature includes many reports on the sclerotherapy of renal cysts with different sclerosing agents. The authors report their experience with the percutaneous treatment of renal cysts by combining pure alcohol and fibrin glue. The glue serves the purpose to seal the walls of the cyst already damaged by alcohol. The results of the combined treatment show that relief of symptoms was obtained in all patients, with no major or minor complications. Complete cyst ablation was obtained only in 16% of cases, while a partial recurrence was seen in 80% of patients, with an average regrowth < 35% of the initial cyst volume. None of these patients presented further symptoms. At present, the follow-up time ranges 3 to 34 months.