Crystal structure of (NH4)2[Fe(II) 5(HPO3)6], a new open-framework phosphite.

Di-ammonium hexa-phosphito-penta-ferrate(II), (NH4)2[Fe5(HPO3)6], was synthesized under mild hydro-thermal conditions and autogeneous pressure, yielding twinned crystals. The crystal structure exhibits an [Fe(II) 5(HPO3)6](2-) open framework with NH4 (+) groups as counter-cations. The anionic skeleton is based on (001) sheets of [FeO6] octa-hedra (one with point-group symmetry 3.. and one with .2.) linked along [001] through [HPO3](2-) oxoanions. Each sheet is constructed from 12-membered rings of edge-sharing [FeO6] octa-hedra, giving rise to channels with a radius of ca 3.1 Šin which the disordered NH4 (+) cations are located. The IR spectrum shows vibrational bands typical for phosphite and ammonium groups.

Catalytic performance of the high and low temperature polymorphs of (C6N2H16)0.5[(VO)(HAsO4)F]: structural, thermal, spectroscopic and magnetic studies.

(C(6)N(2)H(16))(0.5)[(VO)(HAsO(4))F] 1 has been synthesized using mild hydrothermal conditions under autogenous pressure. Above 70 degrees C, this phase has a polymorph with the same chemical composition 2 in which the organic 1,4-diamincyclohexane molecule adopts a different conformation. The crystal structures have been solved from single-crystal X-ray diffraction data. The phases crystallize in the C2/c monoclinic space group with the unit-cell parameters a = 21.065(2) A b = 7.2717(4) A c = 10.396(1) A beta = 104.290(8) degrees for compound 1 and a = 23.025(1) A, b = 7.322(1) A, c = 10.344(1) A and beta = 109.250(6) degrees for compound 2. These phases exhibit a layered inorganic framework, with the template molecule linking the layers via electrostatic interaction and hydrogen bonds. In both phases, the structure is built from secondary building units SBU-4, which are constructed from two [V(2)O(8)F(2)] edge-shared dimeric vanadyl octahedra, connected by the vertices of two hydrogenarsenate (HAsO(4)) tetrahedra. The repetition of this SBU unit gives sheets along the [010] direction. Polymorph 1 exists below 70 degrees C, whereas the limit of thermal stability for 2 is approximately 150 degrees C. Both phases coexist in the temperature range from 80 to -15 degrees C. By means of the DSC technique it has been possible to verify that the temperature of the structural transition is between 70 and 100 degrees C. The diffuse reflectance spectrum of 1 confirms the presence of vanadyl ions, in which the vanadium(IV) cations have a d(1) electronic configuration in a slightly distorted octahedral environment. ESR spectra of both phases are isotropic with mean g values of 1.96 and 1.99 for 1 and 2, respectively. Magnetic measurements for 1 indicate the existence of antiferromagnetic exchange couplings. Both phases are effective and selective catalysts in the oxidation of organic sulfides to sulfoxides and 3,7-dimethylocta-1,6-dien-3-ol.

Microporous vanadyl-arsenate with the template incorporated exhibiting sorption and catalytic properties.

(C(5)H(14)N(2))[(VO)(3)(AsO(4))(HAsO(4))(2)(OH)].3H(2)O behaves as a microporous organically templated compound, with reversible adsorption and desorption of N(2) at 77 K, and as an extremely efficient catalyst that catalyzes selective sulfoxide formation from organic sulfides, under mild conditions.

Mild hydronephrosis in newborns and infants: can ultrasound predict the presence of vesicoureteral reflux.

The objective of our study was to determine the significance of mild hydronephrosis in newborns and infants as an indicator of vesicoureteral reflux (VUR). The voiding cystourethrography (VCUG) of 573 patients aged 0-18 months with mild, sonographically detected hydronephrosis were reviewed for VUR. Patients with secondary reflux or anomalies making an exact reflux grading impossible were excluded. Normal kidneys, contralateral to hydronephrotic ones, were included. Each kidney was considered separately, forming a total of 1,146 renal units. Mild hydronephrosis was defined as an anteroposterior diameter of the renal pelvis of 0.5-1.5 cm without caliectasis. The International Grading System was used to grade VUR. Seven hundred and thirty-six kidneys had mild hydronephrosis. VUR occurred in 189 out of 736 (25.7%) of these kidneys, and in 108 out of 410 (26.3%) non-distended kidneys, contralateral to hydronephrotic ones (p=0.806). No statistical differences in the frequency of VUR and dilatation were found between the subgroups of patients with and without infection, except for a higher grade of reflux in the group with infection. The frequency of VUR in mildly dilated kidneys was not significantly different from that in non-distended ones. There was a poor correlation between VUR and mild hydronephrosis. The latter should not be considered in itself an indication for VCUG in asymptomatic neonates and infants.

Pediatric liver transplantation: a pictorial essay of early and late complications.

Orthotopic liver transplantation is currently the treatment of choice in patients with end-stage liver disease for which no other therapy is available. In children, segmental liver transplantation with living donor, reduced-size cadaveric, and split cadaveric allografts has become an important therapeutic option. However, the resulting expansion of the donor pool has increased the risk for postoperative vascular and biliary complications, which affect children more frequently than adults. Early recognition of these complications requires radiologic evaluation because their clinical manifestations are frequently nonspecific and vary widely. Doppler ultrasonography (US) plays the leading role in the postoperative evaluation of pediatric patients. Current magnetic resonance (MR) imaging techniques, including MR angiography and MR cholangiography, may provide a wealth of pertinent information and should be used when findings at US are inconclusive. Computed tomography is a valuable complement to US in the evaluation of complications involving the hepatic parenchyma as well as extrahepatic sites and is commonly used to guide percutaneous aspiration and fluid collection drainage. Familiarity with and early recognition of the imaging appearances of the various postoperative complications of pediatric liver transplantation are crucial for graft and patient survival.

Aspectos embriológicos, clínicos y radiológicos de la malrotación intestinal / Embryologic, clinical, and radiological aspects of intestinal malrotation

La malrotación intestinal con su propensión al vólvulo representa un desafío diagnóstico en pacientes pediátricos. El diagnóstico precoz es de suma importancia para conseguir un buen resultado. En este artículo se revisan e ilustran los hallazgos radiológicos de la malrotación y el vólvulo de intestino medio en la infancia y adolescencia, y se discuten la embriología, la presentación clínica, el manejo radiológico y la evolución de este proceso. El diagnóstico de malrotación y vólvulo debe tenerse en cuenta siempre que se evalúe a un lactante o niño con vómitos y dolor abdominal, particularmente si los vómitos son biliosos. Un tránsito baritado generalmente dará el diagnóstico. La ecografía es muy útil, si bien no es suficientemente segura para excluir el diagnóstico. Sin embargo, el «signo del remolino» es un signo altamente sensible para el diagnóstico del vólvulo de intestino medio. El radiólogo siempre debe tener presente que esta complicación puede ocurrir a cualquier edad

Intestinal malrotation with its propensity to volvulus represents a diagnostic challenge in pediatric patients. Early diagnosis is of extreme importance for achieving a good outcome. This article reviews and illustrates the radiologic findings for malrotation and volvulus of the small bowel in childhood and adolescence. The embryology, clinical presentation, radiologic management, and evolution of this process are discussed. The diagnosis of malrotation and volvulus should be considered whenever a nursing baby or child presents with vomiting and abdominal pain, especially if the vomit is bilious. A barium follow-through usually provides the diagnosis. Ultrasound is very useful, although it cannot safely rule out the diagnosis. However, the "whirlpool sign" is a highly sensitive sign for the diagnosis of small bowel volvulus. The radiologist needs to bear in mind that this complication can occur at any age

Pancreatic regeneration after near-total pancreatectomy in children with nesidioblastosis.

BACKGROUND: Nesidioblastosis is often resistant to medical therapy and requires near-total pancreatectomy. There is little information on the postoperative imaging findings of these patients. OBJECTIVE: To demonstrate by US the late imaging findings in these patients. MATERIALS AND METHODS: Children diagnosed with nesidioblastosis and who had undergone 90-95% pancreatectomy received preoperative, immediate-postoperative (within 10 days of surgery) and long-term annual US examinations. In the preoperative study, three anterior-posterior (AP) measurements were obtained of the head, body and tail of the pancreas. In the postoperative and long-term follow-up US, AP and transverse measurements of the pancreatic remnant were obtained. Pancreatic echogenicity was also assessed. The results were compared with normal pancreatic dimensions as a function of age. Glucose metabolism and pancreatic enzymes were also analysed. RESULTS: The study group comprised 22 patients (aged 9 days to 2 years). The pancreas was normal in all preoperative US examinations. The first postoperative examination showed, in all patients, a remnant of the pancreatic head measuring 8-13 mm. The last follow-up US was similar to the first postoperative study in 6 patients, and 12 showed complete pancreatic regeneration (normal size, echogenicity and function), and 4 had incomplete regeneration with head and body normal in size, but lack of a pancreatic tail. All patients were asymptomatic and showed normal laboratory tests. CONCLUSIONS: US measurements indicated normal age-dependent growth after near-total resection in 54% of patients. The function and echogenicity of the regenerated pancreas indicate that the increase in organ size was due to normal pancreatic tissue.

Estudio radiológico de las duplicaciones del tracto urinario / Imaging urinary tract duplications

Objetivo: Ilustrar el espectro de hallazgos radiológicos de las duplicaciones del tracto urinario y mostrar la eficacia de los ultrasonidos, la cistouretrografía miccional seriada (CUMS), la urografía intravenosa (UIV), el estudio isotópico y la resonancia magnética (RM) en el manejo de estas entidades. Material y métodos: Hemos revisado retrospectivamente los hallazgos radiológicos de las duplicaciones del riñón, uréter, vejiga y uretra a partir de los datos de nuestro archivo de patología genitourinaria pediátrica. Todos los casos cuentan con estudio ecográfico, mientras que la CUMS, la UIV, el estudio isotópico y la RM se realizaron en función del tipo de duplicación. Hacemos hincapié en las bases em-briológicas de los hallazgos radiológicos que, cuando fue posible, se cotejaron con los hallazgos anatomopatológicos. Resultados: Las duplicaciones completas o incompletas afectaron con más frecuencia al sistema pielocalicial y al uréter (pelvis renal bífida, uréter semibífido, uréter bífido bajo, duplicación ureteral completa y triplicación). Las duplicaciones vesicales se muestran en los planos sagital y coronal, aunque la forma más frecuente fue la división sagital con dos vejigas resultantes contiguas separadas por un pliegue peritoneal con tejido areolar fino. Las duplicaciones uretrales o las uretras accesorias se dieron fundamentalmente en el plano coronal; sin embargo, también describimos la duplicación en el plano sagital en ausencia de duplicación vesical. Mostramos un caso extremadamente raro de duplicación completa de uretra femenina. Conclusión: Mostramos una visión de conjunto de las duplicaciones del tracto urinario y discutimos la utilidad de varias técnicas de imagen disponibles. Dado que estas entidades tienen una apariencia radiológica característica, este artículo puede ser útil para comprender mejor estas anomalías

Objective: To illustrate the spectrum of imaging findings for urinary tract duplications and to show the efficacy of ultrasonography (US), voiding cystourethrography (VCU), intravenous urography (IVU), scintigraphy, and magnetic resonance (MR) in the management of these entities. Material and methods: We have reviewed the imaging findings for cases of renal, ureteral, vesical, and/or urethral duplication from our pediatric genitourinary pathology archive. All patients underwent US examination; VCU, IVU, scintigraphy, and MR studies were perfor-med in function of the type of duplication. We explain our findings within the framework of embryological development and correlate the imaging findings with the histopathologic findings whenever possible. Results: Complete or partial duplications most commonly affected the pyelocalyceal system or the ureters (bifid renal pelvis, bifid mid-ureter, low bifid ureter, complete ureteral duplication and triplication). Vesical duplications are shown in the sagittal and coronal planes, although the most common presentation was sagittal division resulting in two contiguous bladders separated by a peritoneal fold with thin areolar tissue. Ureteral duplication or accessory ureters were mostly seen in the coronal plane; however, we also describe duplication in the sagittal plane in the absence of vesical duplication. We show an extremely rare case of complete duplication of the female urethra. Conclusion: We provide an overview of the set of urinary tract duplications and discuss the usefulness of the different imaging techniques available for each type. As these entities have a typical radiological appearance, this article can help to understand these anomalies better

Pancreatic cystosis in children and young adults with cystic fibrosis: sonographic, CT, and MRI findings.

OBJECTIVE: We sought to analyze the sonographic, CT, and MRI findings of pancreatic cystosis, an unusual form of pancreatic involvement in cystic fibrosis (CF) that is characterized by macrocysts of different sizes distributed throughout the gland. CONCLUSION: CT and MRI essentially confirmed the findings of sonography in all cases, providing no relevant additional information about the nature, internal structure, or content of the cysts. When pancreatic macrocysts are clearly shown on sonography in asymptomatic patients with CF, no additional imaging is warranted.

Vesicoureteral reflux: can the urethra be adequately assessed by using contrast-enhanced voiding US of the bladder?

PURPOSE: To prospectively evaluate contrast material-enhanced voiding ultrasonography (US) for assessment of the urethra by using voiding cystourethrography (VCUG) as the reference standard. MATERIALS AND METHODS: This study was approved by the ethics committee on human research. Written informed consent was obtained for all patients. A total of 146 pediatric patients suspected of having vesicoureteral reflux underwent US with a galactose-based contrast agent. The bladder was instilled with contrast agent and then filled with saline. US images of the urethra were videotaped before catheterization and during voiding. VCUG was subsequently performed in all patients. In female patients, the probe (a 3.5- or 5-MHz sector array or a 7.5-MHz linear transducer) was positioned longitudinally between the labia. In male patients, the transducer was placed longitudinally on the scrotum and then displaced distally toward the penile urethra. During voiding, attention was focused on the distention of the urethral walls and on the caliber of both the posterior and anterior urethra, which were measured with calipers. Sensitivity and specificity were estimated by using a confidence interval (CI) of 95%. RESULTS: All female patients and 75 male patients showed a normal urethra at both US and VCUG. Posterior urethral valves (PUV) were diagnosed in three patients at voiding US and were confirmed with findings from VCUG. Urethral stenosis was diagnosed in two male patients at voiding US and was confirmed with findings from VCUG. Seven male patients who had undergone surgery for PUV were adequately evaluated with both modalities. Sensitivity of voiding US was 100% (CI 95%: 96.5%, 100%); specificity was 100% (CI 95%: 69.9%, 100%). CONCLUSION: Voiding US is a reliable imaging modality for studying the urethra.

Imagen radiológica de las duplicaciones del tubo digestivo / Imaging of digestive tract duplications

Objetivo: Mostrar el espectro de hallazgos de imagen de las duplicaciones del tubo digestivo y evaluar la eficacia de las radiografías simples, estudios baritados, ecografía, diagnóstico mamario (US), tomografía computarizada (TC) y resonancia magnética (RM) en el manejo de estas anomalías. Material y método: Hemos revisado retrospectivamente de nuestra base de datos de patología gastrointestinal pediátrica los hallazgos de imagen de los pacientes con duplicaciones del tubo digestivo. Radiografías simples y estudios baritados se realizaron en todos los casos, mientras que US, TC y RM se realizaron dependiendo de la localización de la duplicación. Se discuten las bases embriológicas y patológicas, se muestran los hallazgos de cada modalidad de imagen y se comparan con los hallazgos anatomopatológicos en algunos casos. Resultados: Las duplicaciones se encontraron por orden de frecuencia en el íleon, esófago, duodeno y colon. En la mayoría de los casos se trataba de quistes esféricos y mucho menos frecuentemente estructuras tubulares situadas en el lado mesentérico del tubo digestivo con quien compartían una pared muscular común y aporte sanguíneo, aunque cada una tenía su propia mucosa. El 40 por ciento de las duplicaciones estaban recubiertas de mucosa gástrica ectópica. Se diagnosticaron por radiografías simples, estudios baritados, US y TC mientras que la RM se reservó para la evaluación de las duplicaciones esofágicas que se presentaron como masas mediastínicas, aunque también fue de utilidad en la evaluación de las duplicaciones abdominales. Conclusión: Aportamos una revisión de las duplicaciones gastrointestinales así como la utilidad de varias técnicas de imagen disponibles para su diagnóstico. Dado que estos desórdenes tienen una apariencia característica, este artículo ayudará al radiólogo a entender mejor estas anomalías (AU)

Congenital anomalies of the tracheobronchial tree, lung, and mediastinum: embryology, radiology, and pathology.

Congenital anomalies of the chest are an important cause of morbidity in infants, children, and even adults. The evaluation of affected patients frequently requires multiple imaging modalities to diagnose the anomaly and plan surgical correction. The authors analyze and illustrate practical aspects of certain common and uncommon congenital anomalies affecting the tracheobronchial tree, lung, and mediastinum, with emphasis on radiologic manifestations. Other thoracic anomalies such as rib anomalies and vascular rings are discussed when they are associated with anomalies of the tracheobronchial tree. The usefulness of the various imaging modalities in the diagnosis and treatment of these conditions is also evaluated. Specific topics addressed include tracheal conditions such as tracheal stenosis, tracheomalacia, tracheal bronchus, tracheal atresia, and bronchogenic cyst; anomalies of the lung such as lung underdevelopment (agenesis and hypoplasia), scimitar syndrome, congenital cystic adenomatoid malformation, congenital lobar emphysema, and pulmonary sequestration; esophageal anomalies such as esophageal atresia, tracheoesophageal fistula, and esophageal duplications; and vascular rings. The embryologic and pathologic basis of the radiologic findings are discussed in appropriate cases. Differential diagnoses, as well as pitfalls and diagnostic difficulties, are included.

Hidronefrosis leve en neonatos y lactantes: ¿puede predecirse la presencia de reflujo vesicoureteral? / Slight hydronephrosis in newborns and breast-fed Infants: can the presence of vesicoureteral reflux be predicted?

Objetivo: El propósito de este estudio fue determinar el valor de la hidronefrosis leve o moderada, detectada mediante ecografía, en recién nacidos y lactantes como indicador de reflujo vesicoureteral (RVU) y evaluar la necesidad de realizar cistouretrografía miccional (CUMS) en estos pacientes. Material y métodos: Se revisaron las CUMS de 237 pacientes (174 niños y 63 niñas, con edades comprendidas entre 0 y 18 meses) con hidronefrosis leve detectada por ecografía, para valorar la presencia de RVU primario. Los pacientes con reflujo secundario o los que presentaban anomalías que imposibilitaban la graduación exacta del reflujo se excluyeron; sin embargo, cuando se observó reflujo en un riñón normal, contralateral al riñón con hidronefrosis, se incluyó en el estudio. Para el análisis estadístico de los datos, cada riñón se consideró por separado, sumando un total de 474 riñones. Se diagnosticó hidronefrosis leve cuando se observó un diámetro anteroposterior de la pelvis renal de 0,5-1,5 cm. Para la graduación del reflujo en la CUMS se utilizó el sistema internacional. Resultados: De las 474 unidades renales evaluadas, 306 mostraron hidronefrosis leve en la ecografía. Sólo 98 de éstas (32 por ciento) presentaron reflujo (14 grado I, 50 grado II, 32 grado III y 2 grado IV). La ecografía fue normal (no mostró hidronefrosis) en 52 unidades renales con reflujo (31 por ciento), contralaterales al riñón hidronefrótico, a pesar de que 38 de estas unidades tenían reflujo grado II o superior. La ecografía mostró hidronefrosis leve en 208 riñones que no tenían reflujo en la CUMS (68 por ciento).Conclusiones: No hubo diferencias significativas en la incidencia de RVU entre los riñones con o sin hidronefrosis. La hidronefrosis leve se correlaciona escasamente con la presencia y el grado de reflujo en neonatos y lactantes y, por tanto, no debe considerarse una indicación para realizar CUMS (AU)

Imaging of orbital disorders in pediatric patients.

The spectrum of orbital lesions occurring in childhood is wide, including a variety of both benign and malignant disorders. Although physical examination and fundoscopy may aid in establishing the diagnosis of retro-ocular lesions, imaging remains a critical step in the evaluation of the pediatric orbit. Ultrasonography, CT, and MR imaging are the primary modalities for the evaluation of the diseased orbit, and careful observation of the characteristic radiological features usually leads to correct diagnosis; however, some of the lesions look very similar and are difficult to differentiate from each other. The purpose of this article is to review the common and unusual entities that may involve the pediatric orbit, to describe the radiological features, and to evaluate the efficacy of US, CT, and MRI in the diagnosis and management of these conditions.

Utilidad del Doppler color y pulsadoen la valoración de los shunts portosistémicosquirúrgicos en la edad pediátrica / Usefulness of color and pulsed Dopplers in the evaluation of surgical portosystemic shunts in pediatric patients

Los shunts portosistémicos se realizan para paliar la hipertensión portal sintomática o para descomprimir la vascularización hepática en pacientes con síndrome de Budd-Chiari. La mayoría de los shunts portosistémicos quirúrgicos pueden estudiarse adecuadamente mediante ecografía complementada con Doppler color y pulsado si se comprende la hemodinámica de los procedimientos quirúrgicos. Este artículo muestra la utilidad y limitaciones de la ecografía duplex Doppler en la evaluación de los shunts portosistémicos realizados a pacientes pediátricos. El Doppler pulsado proporciona información sobre la naturaleza y dirección del flujo sanguíneo y el Doppler color es capaz de mostrar directamente el shunt y, en la mayoría de los casos, permite localizar las anastomosis. Los tipos de shunts que se muestran incluyen esplenorenal proximal y distal, portocava y mesocava. Se ilustran los tipos de conexiones vasculares y se muestra la dirección posquirúrgica esperable del flujo en los vasos sanguíneos implicados. Se discute la técnica ecográfica y los criterios para determinar la permeabilidad vascular.Así mismo se enfatizan las ventajas, limitaciones y dificultades diagnósticas de las distintas modalidades del Doppler (AU)

Heterotopic gastric mucosa involving the gallbladder and biliary tree.

A case of heterotopic gastric mucosa in the common bile duct, cystic duct and gallbladder is reported in a 3-year-old girl with abdominal pain and jaundice. Abdominal US and CT showed dilatation of the biliary tree and a well-defined mass in the common bile duct that narrowed its lumen. The gallbladder was contracted in both examinations. The common bile duct and the gallbladder were resected and a choledochojejunostomy was performed. Although gastric heterotopy has been described throughout the entire length of the gastrointestinal tract, it is a very uncommon finding in the gallbladder and extremely rare in the biliary tree. A firm diagnosis of gastric heterotopia is based on the presence of fundal mucosa replete with parietal and chief cells. To our knowledge, this is the fifth reported case of heterotopic gastric tissue within the common bile duct, and the first to describe the US and CT findings. A relevant literature review and brief outline of the histological and radiological features are included in the discussion.

Anomalies of the distal ureter, bladder, and urethra in children: embryologic, radiologic, and pathologic features.

Congenital anomalies of the lower urinary tract are a significant cause of morbidity in infancy. Radiologic investigation is an important source of clinical information in lower urinary tract disorders but should not inconvenience the patient, expose the patient to unnecessary radiation, or delay surgical correction. In pediatric patients with suspected underlying urologic structural anomalies, screening ultrasonography is commonly the initial diagnostic study. If dilatation of the urinary tract is confirmed, voiding cystourethrography is performed to determine the presence of vesicoureteral reflux (VUR) and other causes of upper tract dilatation. If VUR is confirmed, follow-up with nuclear cystography or echo-enhanced cystosonography may be performed. If VUR is excluded, nuclear diuresis renography is the primary test for differentiating between obstructed and nonobstructed megaureter. Intravenous urography can be used to specifically identify an area of obstruction and to determine the presence of duplex collecting systems and a ureterocele. Computed tomography and magnetic resonance (MR) imaging are unsuitable for general screening but provide superb anatomic detail and added diagnostic specificity. MR imaging is mandatory in the evaluation of associated spinal anomalies. MR urography can demonstrate ectopic extravesical ureteric insertions, thereby providing a global view of the malformation. Familiarity with anomalies of the lower urinary tract is essential for correct diagnosis and appropriate management.