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The optimal management of hemorrhagic cystitis (HC) in hematopoietic stem cell transplantation (HCT) is debated, both for early onset HC (EOHC) secondary to chemotherapy toxicity and BK Polyomavirus (BKPyV)-related HC, due to the lack of controlled trials, particularly referred to pediatric setting. Actually, clinical practice is mainly based on guidelines of the European Conference on Infections in Leukemia, 6 th edition, which considers both adult and pediatric populations but concludes that, despite much progress in understanding the pathogenesis, epidemiology, and risk factors, this complication still represents a disabling unmet clinical need with limited prophylactic and therapeutic options. Additionally, the Guidelines of the American Society of Clinical Oncology define the management of chemotherapeutic toxicity independently from the patients' population. A panel of experts belonging to the Hematopoietic Cell Transplant and Infectious Disease Working Group (WG) of Associazione Italiana di Emato-Oncologia Pediatrica (AIEOP) developed a consensus to define the best practices in prevention, diagnosis, and management of HC in pediatric HCT setting., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: Lower urinary tract symptoms (LUTS) and nocturnal enuresis (NE) are complex conditions requiring a long-term follow-up. Telemedicine is an emerging technological tool in the surgical field, and its availability exponentially grew during the COVID-19 pandemic, expanding its application fields, optimizing technical aspects, reducing costs, and ensuring high-quality standards. This work describes our experience with telemedicine in a Division of Pediatric Urology for the follow-up of enuresis and LUTS., Methods: A retrospective analysis of our telemedicine preliminary experience was conducted at Regina Margherita Children's Hospital in Turin, Italy. This study included all the patients aged <18 years who were monitored for enuresis and LUTS through telemedicine between September 1, 2021 and July 31, 2023. Clinical data and outcomes were analyzed, and patients and families were asked to voluntary fill an evaluation questionnaire on their satisfaction. Additionally, we focused on the post COVID-19 period, between September 2022 and July 2023, analyzing the data of two different patients' populations: the first one (G1) of patients choosing telemedicine outpatients visits (TOVs) and the second one (G2) of those choosing a face-to-face visit., Results: One hundred five patients were enrolled. One hundred sixty-two TOVs were performed. The median age at first visit was 9.7±0.66 years (range 7-16 years). Diagnosis were: 77/105 (67%) NE and 28/105 (33%) LUTS. The average referred distance between the patients' residence and the hospital was 46.35±129.37 km (range 2-1300 kilometers) and the time taken to overcome it was 44.21±77.29 minutes (range 10-780 minutes). In 64/105 cases (61%) the follow-up was interrupted for total healing or symptoms resumption. Only two cases (2%) required the conversion to an in-person ambulatory consult, due to a social-linguistic barrier. 146/162 families (90%) filled the survey questionnaire at the end of each TOV, reporting in 94% of cases a high satisfaction level. In the comparative statistical analysis of the two patient groups, G1 (52 telemedicine office visits, [TOVs]) vs. G2 (25 face-to-face visits), the average referred distance was 17.78±7.98 km (range: 5-35 km) for G1, contrasting with 7.04±3.35 km (range: 2.5-14 km) for G2 (P=0.00001). Additionally, the waiting time before the visit was 3.96±2.90 minutes (range: 0-10 minutes) for G1, in contrast to 26.52±11.22 minutes (range: 5-44 minutes) for G2 (P=0.00001). Furthermore, a higher compliance with behavioral or pharmacological indications was observed in the G1 group, exhibiting lower adherence in only 12 out of 52 cases compared to 14 out of 25 cases in G2 (P=0.0091)., Conclusions: Telemedicine is a proper solution and an effective tool to manage the therapeutic follow-up of NE and LUTS, ensuring suitable quality standards and reducing social costs, such as the loss of working days and transport costs. The implementation and complete integration of its use into the healthcare system should be the goals to pursue in order to take full advantage of all its potentials.

Introduction: Few studies in the literature describe the Retrograde Intra-Renal Surgery (RIRS) outcome in preschool children. We evaluated the feasibility, stone-free rate and complications of RIRS in preschool children at two European tertiary care centres of Pediatric Urology., Material and Methods: The retrospective study includes all children undergone RIRS for stones <25 mm from 2017 to 2022. Patients were divided into Group 1 <5 years (G1) and Group 2 >5 years (G2). Semirigid ureterorenoscope 4.5-6.5 Ch and a 7.5 Fr flexible ureteroscope with a 9.5/11 Ch ureteral access sheath (UAS) were used. Stone-free rate (SFR) was evaluated at 3 months. Fischer/Chi-square test for qualitative data and Mann-Whitney for quantitative data were used for statistical analysis., Results: 63 patients underwent RIRS, 19 G1-patients, median age 3.55 ± 1.06 years (range 1.5-5 years), and 44 G2-patients, median age 11.25 ± 2.95 (range 6-17 years) (p < 0.00001). Intraoperative complications occurred in 1 case in G1(5%) and 3 in G2(7%) (p = 1): two minor ureteric injuries in G2 were treated by a prolonged JJ-stent. Postoperative fever was reported in 3 cases in G1 (16%) and 4 in G2(9%) (p = 0.42), while post-operative hematuria in 4 G1-patients (21%) and in 7 G2-patients (16%) (p = 0.72). SFR was 84.2% in G1 and 88.6% in G2. At an average follow-up of 15.05 ± 4.83 months in G1 and 19.95 ± 10.36 months in G2, reintervention for residual stones was necessary in 3 cases in G1(16%) and in 6 cases in G2(14%) (p = 1)., Conclusions: In a European country with low-volume pediatric stone centers, RIRS is a promising therapeutic option in young children as it offers acceptable stone-free rate and a low incidence of high-grade complications., Level of Evidence: III., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Double-J ureteral stents are usually placed after various urological procedures. The dislodgement of their distal ringlet is a rare complication, whose retrieval is arduous in younger children, due to the small ureteral caliber. We propose our innovative endoscopic approach to recover the dislodged JJ stent. Under 8-9.8 Ch cystoscopy, the ureteral meatus is gently cannulated with a 00.18″ guidewire, then a balloon catheter Passeo 18 3-4 mm (Biotronik, Lake Oswego, OR, USA) is coaxially inserted. A pneumatic dilatation of the vesical-ureteral junction is performed up to 8 atmospheres for 5 minutes under direct vision. Consequently, the ureteral meatus allows the cystoscope passage, and the JJ-stent can be recovered thanks to endoscopic grasping forceps. A mono-J stent is then left in place for 24 hours. Four patients aged 8 months - 4 years have been successfully treated with this approach after that JJ migration was found intraoperatively or during ultrasonography. No intra- or postoperative complications occurred. Postoperative hospital stay was prolonged for one day. During 29.5 medium follow-up no clinical or ultrasonographic signs of vesical-ureteral reflux ensued. Our cystoscopic approach is effective and safe to ensure a prompt endoscopic JJ retrieval without changing neither surgical approach nor the anesthesiological support. We believe that all the pediatric urology centers should know the procedure and have small size balloon catheter available.

Adding a secondary complex metal hydride can either kinetically or thermodynamically facilitate dehydrogenation reactions. Adding Mg 2 FeH 6 to LiBH 4 is energetically favoured, since FeB and MgB 2 are formed as stable intermediate compounds during dehydrogenation reactions. Such "hydride destabilisation" enhances H 2 -release thermodynamics from H 2 -storage materials. Samples of the LiBH 4 and Mg 2 FeH 6 with a 2:1 molar ratio were mixed and decomposed under three different conditions (dynamic decomposition under vacuum, dynamic decomposition under a hydrogen atmosphere, and isothermal decomposition). In situ synchrotron X-ray diffraction results revealed the influence of decomposition conditions on the selected reaction path. Dynamic decomposition of Mg 2 FeH 6 -LiBH 4 under vacuum, or isothermal decomposition at low temperatures, was found to induce pure decomposition of LiBH 4 , whilst mixed decomposition of LiBH 4 + Mg and formation of MgB 2 were achieved via high-temperature isothermal dehydrogenation.

Amongst the more than 18 different forms of water ice, only the common hexagonal phase and the cubic phase are present in nature on Earth. Nonetheless, it is now widely recognized that all samples of 'cubic ice' discovered so far do not have a fully cubic crystal structure but instead are stacking-disordered forms of ice I (namely, ice Isd), which contain both hexagonal and cubic stacking sequences of hydrogen-bonded water molecules. Here, we describe a method to obtain large quantities of cubic ice Ic with high structural purity. Cubic ice Ic is formed by heating a powder of D 2 O ice XVII obtained from annealing of pristine C 0 hydrate samples under dynamic vacuum. Neutron diffraction experiments performed on two different instruments and Raman spectroscopy measurements confirm the structural purity of the cubic ice, Ic. These findings contribute to a better understanding of ice I polymorphism and the existence of the two natural ice forms.

Deuterated ice XVII, a metastable solid water polymorph, was filled with Ne and O2 at p ≈ 100 kPa and studied by in situ neutron diffraction (ILL, France). Powder patterns were collected in the ranges of 20-50 K (Ne) and 4.6-90 K (O2). Rietveld refinement and difference Fourier techniques showed that the gas molecules were located inside the hexagonal channels of the host ice. Both Ne atoms and O2 molecules are arranged in a spiral-like configuration off the channel axis, preserving the P6122 symmetry of the host in the case of Ne, but reducing it to P61 in O2. A larger Ne absorption compared to Ne-filled ice II is observed, which is consistent with longer host-guest contacts producing smaller hydrophobic repulsion. In O2-filled ice XVII, instead, short O-D distances (2.37 Å) have attractive character and stabilize the structure.

Objective: The aim of this study was to describe the technical aspects of a robotic pyeloplasty in pediatric patients with uretero-pelvic junction obstruction (UPJO) in horseshoe kidney (HSK) through the report of our recent case, and to outline the state of the art of minimally invasive pyeloplasty (MIP) with a systematic review of the literature., Methods: We describe all the steps of our surgery performed on an 11-year-old patient with left UPJO in HSK in detail. All the anatomic landmarks are clearly showed, with particular attention to trocar placement in a pediatric patient. A systematic review of the literature on the outcomes of MIP in HSK patients has been performed, including 16 articles., Results: Our surgery was successful following a standardized approach. However, we recorded a rare complication, the herniation of a small portion of omentum through the 8 - mm defect used for the caudal robotic port. The evidence synthesis shows excellent postoperative outcomes for both laparoscopic and robot-assisted laparoscopic pyeloplasties in HSK patients. Probably, MIP should be preferred to the traditional open approach in these patients, when feasible., Conclusions: Transperitoneal robotic pyeloplasty is an excellent minimally invasive choice for the treatment of UPJO in HSK pediatric patients. The pediatric setting should prompt attention to every detail to avoid unfortunate complications.

Monoclinic α-Nb2O5 was chemically lithiated by reaction with n-butyllithium, mimicking the product of electrochemical discharge of a niobium oxide cathode vs. a Li anode. The compound was investigated by neutron powder diffraction (D2B equipment at ILL, France) and its structure was Rietveld refined in space group P2 to wRp = 0.045, locating the Li atoms inserted in the α-Nb2O5 framework. The ensuing chemical formula is Li12/7Nb2O5. Some Li atoms are more strongly bonded (five coordinated O atoms), some are less strongly bonded (coordination number = 4). Starting from the experimental structure, first-principles periodic DFT calculations based on the hybrid B3LYP functional were performed. The electrochemical voltage of Li insertion was computed to be 1.67 V, fully consistent with the experimental 1.60 V plateau vs. capacity. The analysis of the electron band structure shows that lithiation changes the insulating oxide into a semi-metal; some of the extra electrons inserted with lithium become spin-polarized and give the material weak ferromagnetic properties.

In the present study we report neutron spectroscopic measurements on polycrystalline lithium imide, namely, incoherent inelastic neutron scattering at 20 K, and neutron Compton scattering from 10 K up to room temperature. From the former technique the H-projected density of phonon states up to 100 meV is derived, while the latter works out the spherically averaged single-particle (i.e., H, Li, and N) momentum distributions and, from this, the mean kinetic energies. Only for H at the lowest investigated temperature, non-gaussian components of its momentum distribution are detected. However, these components do not seem directly connected to the system anharmonicity, being fully compatible with the simple N-H bond anisotropy. Neutron data are also complemented by ab initio lattice dynamics simulations, both harmonic and, at room temperature, carried out in the framework of the so-called "quantum colored noise thermostat" method. The single-particle mean kinetic energies in lithium imide as a function of temperature show a quite peculiar behavior at the moment not reproduced by ab initio lattice dynamics methods, at least as far as H and Li are concerned. As matter of fact, neither their low temperature values nor their temperature trends can be precisely explained in terms of standard phonon calculations.

Models for Li(+) ion mobility were developed and investigated in the 'corrugated layer' orthorhombic phase of Li(1-x)FeO(2), an attractive possible electrode material for reversible lithium ion batteries. The ground-state crystal energy was computed by first-principles DFT (Density-Functional-Theory) methods, based on the use of the hybrid B3LYP functional with localized Gaussian-type basis sets. Appropriate supercells were devised as needed, with full least-energy structure optimization. In the defect-free case (x = 0), ion diffusion was found to take place cooperatively inside a fraction of active lithium layers separated by inert ones, so as to reduce lattice strain; intermediate bottleneck states of Li are either in tetrahedral (energy barrier ΔE(a) = 0.410 eV) or linear (ΔE(a) = 0.468 eV) coordination. For the Li(0.75)FeO(2) deintercalated material a number of low energy vacancy configurations were considered, investigating also the vacancy influence on electron density of states and atomic charge distribution. The most favourable ion transport mechanisms (ΔE(a) = 0.292 and 0.304 eV) imply a linear Li bottleneck state, with all lithium layers active and a quite small lattice strain. Accordingly, in the defective material the predicted ionic conductivity at room temperature rises from 10(-5)-10(-6) (LiFeO(2)) to 4 × 10(-4) ohm(-1) cm(-1) (Li(0.75)FeO(2)).

First-principles periodic calculations (with the B3LYP (Becke, three-parameter, Lee-Yang-Parr) hybrid functional, all-electron localized basis functions, and the CRYSTAL code) were coupled to a cluster expansion scheme in order to investigate the monoclinic β' phase of LiFeO(2), where a partially disordered Fe-Li distribution is observed within a rocksalt-type superstructure. By least-energy optimizing a limited number of ordered configurations, and employing a two-body truncated cluster expansion, the values J(1) = -0.06(2) and J(2) = -0.125(8) eV were obtained for the excess interaction energies J(i) = J(LiFe, i) - (J(LiLi, i) + J(FeFe, i))/2 corresponding to the first and second coordination spheres, respectively; negligible values were computed for third and further coordinations. The ordering phase transformation α−>β'−>γ was then addressed. Antiferromagnetic versus ferromagnetic ordering was taken into account too, and proved to lower the energy by -0.0577 eV/f.u. The corresponding cluster expansion coefficients J(i) = J(AFM, i) - J(FM, i) are J(1) = 0.007(2) and J(2) = -0.044(5) eV., (© 2010 IOP Publishing Ltd)

The interaction between sulfur-containing chromophores and cationic species (K(+)) has been investigated in dye-loaded zeolite materials by means of photoluminescence spectroscopy. A red-shift in the emission spectra of the host-guest compounds (HGCs) has been detected and unambiguously connected to the close proximity between a conjugated moiety and nearby free charges, suggesting a specific role played by sulfur lone pair electrons. Quantum-chemical calculations on model compounds have been performed to support this hypothesis.

Objective: To compare outcomes of the original Koyanagi technique with the Hayashi modification in severe hypospadias, i.e. hypospadias with a division of the corpus spongiosum located behind the penile midshaft associated with marked hypoplasia of the ventral aspect of the penis and a non-preservable urethral plate. Choice of technique for treating severe hypospadias is discussed., Patients and Methods: Twenty-six patients (group I) were operated in Lyon using the original Koyanagi procedure and 31 (group II) underwent a modified Hayashi procedure in Paris. Most patients received preoperative androgenic stimulation. Mean follow up was 25 months (group I) and 34 months (group II)., Results: Sixteen patients (61.5%) in group I and 19 (61.3%) in group II developed complications leading to 21 additional procedures in each group. Urethral dehiscence was found in 11/26 patients in group I (42.3%), and in 6/31 patients in group II (19.3%); fistulae were respectively found in 5/26 (19.2%) and 12/31 (38.7%), and stenosis in 9/26 (34.6%) and 5/31 (16.1%) patients. Urethrocele was found in 7/26 (26.9%) and 5/31 (16%) patients, respectively. Twelve (group I) and 7 (group II) patients are awaiting re-operation., Conclusion: Although the complication rate is quite similar between the original and the modified Koyanagi procedure, the Hayashi technique seems to provide a better distal blood supply to the reconstructed urethra.

Objective: To compare the outcomes of three different urethroplasty techniques (onlay, buccal mucosa, Koyanagi type I) used in the reconstruction of severe hypospadias., Patients and Methods: Over 10 years (1997-2007), 300 severe hypospadias cases were treated with a mean follow up of 2 years (1-105 months); 203 were operated by the same surgeon of whom 184 completed follow up. Three main techniques were used according to the quality of the urethral plate: onlay urethroplasty (133), buccal graft urethroplasty (25) and Koyanagi type I (26). The mean age at surgery was 36 months (8-298); 76 required preoperative androgen stimulation (onlay 37, buccal 11, Koyanagi 26); 18 required a corporoplasty to straighten the penis (onlay 13, buccal 3, Koyanagi 2)., Results: Thirty-eight onlay (28.5%); 14 buccal (56%); 16 Koyanagi (61.5%) urethroplasties had a complication. The fistula rate was 15% for the onlay group; 32% for the buccal mucosa group; 19.2% for the Koyanagi cases. The dehiscence rate was, respectively, 11.3%, 20% and 42.3%. The stricture rate was, respectively, 1.5%, 20% and 34.6%. Urethrocele was found in seven Koyanagi patients. Final functional and cosmetic results were satisfactory in 126/133 (94.7%) onlay, 20/25 (80%) buccal and 14/26 Koyanagi (53.8%) urethroplasties. Primary cases had better results (89%) than redo cases (75.9%). Patients submitted to preoperative androgen therapy developed more complications (onlay: 40.5% vs 23.9%; buccal: 70% vs 43.7%)., Conclusion: Two striking results are the low number of severe hypospadias cases requiring an additional corporoplasty, and the increased complication rate found in androgen-stimulated patients. The excellent results of the onlay procedure could be related to the use of dorsal preputial tissue, which in hypospadias is characterized by a well-balanced protein platform compared to the ventral tissues.

Purpose: We evaluated functional results with an artificial urinary sphincter in children and adolescents in terms of complications, continence and voiding ability through followup., Materials and Methods: A total of 44 patients (39 males and 5 females, age 8.6 to 29.5 years, median 14) underwent implantation of a pericervical AMS 800trade mark artificial urinary sphincter, primarily for severe urinary incontinence of neuropathic origin, between 1986 and 2005. Of the patients 25 had undergone augmentation cystoplasty previously (8), simultaneously (7) or after implantation (10). Median followup was 5.5 years (range 1 to 18). Complications included dysuria and/or urinary retention (24 cases), worsening of bladder function (13), urethral erosion (2), scrotal erosion (5), mechanical dysfunction (7), infection of the artificial urinary sphincter (2) and accidental puncture of the tubes (2). These complications resulted in 9 removals, 5 deactivations, 6 revisions and 5 total replacements., Results: Of 44 patients 9 (20%) were incontinent after removal of the artificial urinary sphincter. Among the remaining patients 32 (73%) were dry and 3 (7%) were incontinent with a deactivated device. Of the 35 patients with an artificial urinary sphincter in place 17 (48.6%) voided to completion with spontaneous voiding, 9 (25.7%) performed post-void clean intermittent catheterization and 9 (25.7%) emptied exclusively with clean intermittent catheterization. The ability to maintain voiding to completion after implantation was significantly decreased when the artificial urinary sphincter was implanted before puberty (p = 0.0025) or in conjunction with an augmented bladder (p = 0.01)., Conclusions: The artificial urinary sphincter provides a good rate of continence. However, complications are frequent, leading to removal in 20% of the cases. In time only a limited number of patients can empty the bladder without clean intermittent catheterization.

Many classifications of hypospadias have been published, mainly based on the position of the ectopic meatus, which is an insufficient criterion to define the severity of this malformation. What really marks the proximal landmark of this malformation is the level of division of the corpus spongiosum, which is always proximal to the ectopic meatus. In this article, we will focus on the most severe forms of hypospadias which include those with a proximal division of corpus spongiosum (below the midshaft), important chordee and a poor development of the ventral radius, reflecting a marked hypovirilization of the genital tubercle, and cripple hypospadias resulting from several previous failed surgical procedures. The principle of hypospadias surgery will be reviewed together with the outcome of the current surgical techniques. Furthermore, common complications will be outlined. There is no minor or major hypospadias and all forms require a solid experience of the surgeon, as minor looking hypospadias may turn out to be far more complex to repair than they appear once the ventral radius of the penis has been dissected.

The theoretical study of pressure-driven phase transformations by means of ab initio quantum mechanical methods, in the frame of the extended Landau approach, is considered. A specific application to AgCl is presented: the system shows, on increasing pressure, four polymorphs with rock salt- (Fmm), KOH- (P2(1)/m), TlI- (Cmcm), and CsCl- (Pmm) type structures. The method of constant-pressure enthalpy minimization was used for all phases, by fully relaxing the corresponding crystal structures. Periodic ab initio energy calculations were performed by the CRYSTAL03 code, employing a DFT-GGA-PBE functional with a localized basis set of Gaussian-type functions. The three phase transitions were predicted to occur at 3.5, 6.0, and 17.7 GPa, respectively, against pressures of 6.6, 10.8, and 17 GPa from literature experimental results. The rock salt- to KOH-type and KOH- to TlI-type displacive transformations show a weak first-order character. The TlI- to CsCl-type reconstructive transition is sharply first-order, and its kinetic mechanism was studied in detail on the basis of a P2(1)/m pathway, similar to that previously found for the rock salt- to CsCl-type transformation of NaCl. An activation enthalpy of 0.011 eV was found at the equilibrium pressure of 17.7 GPa.

Objective: To assess the quality of life of 23 female patients over 18 years of age treated and followed in the same institution., Methods: Fifty questions were sent to this group of patients covering their uro-gynaecological history, education and profession, social life and related psychological issues, sexual life and fertility. All replies were kept anonymous., Results: Seventeen patients (74%) replied. Urine incontinence at various degrees was found in 65%. Genital prolapse was reported in 29.5%. Students accounted for 41%; 59% were actively working with a satisfactory professional life in 82% of cases. Seventy-six per cent did not consider that exstrophy affected their professional life, and 76% were happy with their social life. Psychological distress was reported by 41%, and the symptoms are detailed. Sixty-four per cent were married or had a stable partner. Seventy-six per cent were active sexually, all declaring heterosexual relations. Eighty-eight per cent had periods. Four pregnancies were reported and morbidity during gestation is described. All children were born by Caesarean section and were normal. These results are discussed and compared with the literature., Conclusion: Despite many hurdles, this group of patients can expect a subnormal social, family and professional life. Urinary incontinence and poor body image were the most important factors altering quality of life.

This is a review of literature scanning the potential factors which may affect Sexual Identity (S.I.) and Gender Identity (G.I.) in patients with ambiguous genitalia. Definitions of these concepts are outlined. Genetic, gonadal, hormonal, social and cultural pressures are reviewed as well as lessons to learn from clinical experiences and outcomes. Current criteriae used to assign gender in a child with ambiguous genitalia are discussed including medical and surgical criteriae as well as cultural disruptors. At the dawn of the third millennium, it is remarkable how little we know about the establishment of our individual and social identities.

The vibrational spectrum of Ca3Fe2Si3O12 andradite is calculated at the Gamma point by using the periodic ab initio CRYSTAL program that adopts an all-electron Gaussian-type basis set and the B3LYP Hamiltonian. The full set of frequencies (17 IR active, 25 Raman active, and 55 inactive modes) is calculated. The effect of the basis set on the calculated frequencies is discussed. The modes are characterized by direct inspection of the eigenvectors and isotopic substitution. The present calculations permit us to clarify some of the assignment problems raised by experiments. The mean absolute differences of the various modes with respect to the available experimental IR and Raman data are as small as 9 and 5 cm(-1), respectively.

Background: In the experience of other authors, double kidney transplant have a higher complication rate (30%) if compared with single renal graft. In personal experience the use of small calibre ureteral stents with antireflux valve can reduce this complication rate., Methods: From November 1999 to April 2001, at the A.S.O. S. Giovanni Battista in Turin, we performed 29 double kidney transplantations with the application of small calibre stents in 20 male and 9 female patients, aged 50-74 years. The uretero-neocystostomies were carried out according to Lich-Gregoire technique, and the JJ stents used were pediatric ones, 12 cm long and 4.8 Ch, with antireflux valve., Results: We complained only 2 urological complications out of 58 anastomoses (distal unilateral ureteral necrosis in 1 case and total ureteral necrosis in the other)., Conclusions: Complication rate is lower than in the literature: the authors suggest that the use of small calibre JJ stents can keep the complication rate low in double kidney transplant.

The mechanism of the B3/B1 phase transition of SiC has been investigated by periodic LCAO-DFT least-enthalpy calculations. A new transformation pathway, based on a Pmm2 orthorhombic intermediate state with two SiC units per cell, is found to be energetically favored over the traditional R3m mechanism. The computed activation enthalpy is 0.75 eV/SiC unit at the predicted transition pressure of 92 GPa (B3LYP functional). Activation enthalpy and activation volume vs pressure are analyzed to characterize the kinetic aspects of the transformation.

Background: We report our experience in transplantation proceedings with the use of small caliber JJ ureteral stent with antireflux valve during uretero-vesical anastomosis., Methods: During renal transplantations we usually perform an uretero-cystoneostomy with antireflux technique according to Lich Gregoir. In the past we used to intubate the uretero-vesical anastomosis only in particular cases; since April 1998 we performed 112 single and 8 double transplants and in all cases we positioned a 12 cm long paediatric 4.8 Ch JJ ureteral stent with antireflux valve, in order to reduce urologic complications. The vesical catheter was usually removed in 6o-7o day and the ureteral stent 40-60 days after transplantation., Results: We have performed 129 uretero-vesical anastomoses and we complained only one case of early dehiscence of the anastomosis (unilateral in a double transplant) and two cases of late stents' displacement. We noticed no stenosis of the anastomosis and no dysfunction in urine outflow from the upper urinary ways., Conclusions: The routinary use of paediatric JJ ureteral stents with antireflux valve was decisive in drastically reducing early urologic complications after renal transplantation. Furthermore, the risk of vesico-ureteral reflux is almost completely reduced, thanks to the technique adopted for the anastomosis which allows a physiologic-like antireflux mechanism, to the presence of the antireflux valve and to the early recovery of the physiologic ureteral peristalsis, which is promoted by the small calibre of the stent. These factors lead to a faster recovery of the renal function, with excellent results from the nephrologic and urologic points of view.

Background: To evaluate survival rate, follow-up and renal function in patients treated with "nephron-sparing" approach due to cancer in a transplanted kidney., Methods: During the 18 years' activity of our Transplantation Centre 3 renal carcinomas in transplanted kidneys (0.24%) have been found. Diagnoses were made in one case during transplantation procedures and, in the remaining two, 1 month and 10 years after. All tumours were unifocal, small (10, 12 and 18 mm of diameter), capsulated and low stage (T1). The resection of the mass ("nephron-sparing" surgery) and of a layer (1 cm thick) of the tissue surrounding the tumour was performed. The histological exam showed in all cases low grade (G2) renal cell carcinoma and negative surgical margins., Results: 138, 94 and 15 months after transplant all patients are alive, without disease recurrence and with good renal function. In all cases the doses of immune-suppressive therapy were reduced., Conclusions: Renal cancer in transplanted kidneys is generally treated with nephrectomy. On the contrary, we decided to apply the same criteria which are accepted for the treatment of renal neoplasms in general and then to perform a "nephron-sparing" surgery when the tumour is small, capsulated and with negative surgical margins at the intraoperative histological exam. In personal experience good results from the oncologic and nephrologic point of view have been accomplished.