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[Urinary calculi and Munchausen syndrome].

BACKGROUND: Unlike the so-called Munchausen syndrome by proxy, which is a form of child abuse, Munchausen syndrome is seldom reported in pediatric literature. CASE REPORT: Anthony, an 8.5-year-old child, was referred because he passed several urinary stones. Although biological findings and urinary tract ultrasonography were normal, intravenous pyelogram showed a round area of decreased density in front of the anterior urethra, which disappeared from postmicturation X-ray. For a 1 month period, the child passed 20 stones without intense pain. After undergoing an appendectomy, he was readmitted for left lumbar pain which disappeared after passage of a stone. He spent the following 10 months without any complaint. On later re-admission with similar symptoms, Munchausen syndrome was suspected because of the discrepancy arising from the emission of stones on one hand and the absence of nephritic colic, of hematuria and of urinary tract dilatation on the other hand. Diagnosis of Munchausen syndrome was confirmed by chemical analysis which reported that samples were in fact ordinary pebbles and by child's confession, during interrogation without his parents, to having introduced the pebbles into his urinary tracts. CONCLUSION: When unusual clinical features are present in children, it is necessary to evoke the Munchausen syndrome which can be likened to a distress signal revealing the presence of psychological disorders.

Child↗

Reactions of the dirhenium(II) complex Re2Cl4(mu-dppm)2 with pyridinecarboxylic acids. Examples of bidentate O,O versus N,O coordination and tridentate O,N,O coordination and structural isomers that contain the pyridine-2,6-dicarboxylate ligand.

Pyridine-2-carboxylic acid, pyridine-2,3-dicarboxylic acid, and pyridine-2,4-dicarboxylic acid or their [(Ph(3)P)(2)N](+) salts react with the triply bonded dirhenium(II) complex Re(2)Cl(4)(mu-dppm)(2) (dppm = Ph(2)PCH(2)PPh(2)) in refluxing ethanol to afford unsymmetrical substitution products of the type Re(2)(eta(2)-N,O)Cl(3)(mu-dppm)(2), where N,O represents a chelating pyridine-2-carboxylate ligand (N,O = O(2)C-2-C(5)H(4)N (1), O(2)C-2-C(5)H(3)N(-3-CO(2)Et) (3), or O(2)C-2-C(5)H(3)N(-4-CO(2)H) (4)). The carboxylate groups in the 3- and 4- positions are not bound to the metal centers; in the case of 3 this group undergoes esterification in the refluxing ethanol solvent. Structure determinations have shown that 1, 3, and 4 possess similar structures in which there is an axial Re-O (carboxylate) bond (collinear with the Re(triple bond)Re bond) and the mu-dppm ligands are bound in a trans,cis fashion to the two Re atoms which have the ligand atom arrangement [P(2)NOClReReCl(2)P(2)]. The tridentate dianionic pyridine-2,6-dicarboxylate ligand (dipic) reacts with Re(2)Cl(4)(mu-dppm)(2) in ethanol at room temperature to give a compound Re(2)(dipic)Cl(2)(mu-dppm)(2) (6) in which the dipic ligand is bound in a symmetrical eta(3)-(O,N,O) fashion to one Re atom, with the N atom in an axial position (collinear with the Re(triple bond)Re bond) and with preservation of the same trans,trans coordination of the mu-dppm ligands that is present in Re(2)Cl(4)(mu-dppm)(2). Under reflux conditions, this kinetic product isomerizes to the thermodynamically favored isomer 5 with an unsymmetrical structure in which the dipic ligand chelates to one Re atom (as in 1, 3, and 4) and uses its other carboxylate group to bridge to the second Re atom. The isomerization of 6 to 5, which also results in a change in the coordination of the pair of mu-dppm ligand to trans,cis, is believed to occur by a partial "merry-go-round" process, a mechanism that probably explains the structures of the thermodynamic products 1, 3, and 4. The reaction of Re(2)Cl(4)(mu-dppm)(2) with pyridine-3-carboxylate gives the trans isomer of Re(2)(mu:eta(2)-O(2)C-3-C(5)H(4)N)(2)Cl(2)(mu-dppm)(2) (2) in which a pair of carboxylate bridges are present and the pyridine N atom is not coordinated. Single-crystal X-ray structural details are reported for 1-6.

Journal Article↗

Reconstitution and analysis of soluble inhibin and activin receptor complexes in a cell-free system.

Activins and inhibins compose a heterogeneous subfamily within the transforming growth factor-beta (TGF-beta) superfamily of growth and differentiation factors with critical biological activities in embryos and adults. They signal through a heteromeric complex of type II, type I, and for inhibin, type III receptors. To characterize the affinity, specificity, and activity of these receptors (alone and in combination) for the inhibin/activin subfamily, we developed a cell-free assay system using soluble receptor-Fc fusion proteins. The soluble activin type II receptor (sActRII)-Fc fusion protein had a 7-fold higher affinity for activin A compared with sActRIIB-Fc, whereas both receptors had a marked preference for activin A over activin B. Although inhibin A and B binding was 20-fold lower compared with activin binding to either type II receptor alone, the mixture of either type II receptor with soluble TGF-beta type III receptor (TbetaRIII; betaglycan)-Fc reconstituted a soluble high affinity inhibin receptor. In contrast, mixing either soluble activin type II receptor with soluble activin type I receptors did not substantially enhance activin binding. Our results support a cooperative model of binding for the inhibin receptor (ActRII.sTbetaRIII complex) but not for activin receptors (type II + type I) and demonstrate that a complex composed of activin type II receptors and TbetaRIII is both necessary and sufficient for high affinity inhibin binding. This study also illustrates the utility of this cell-free system for investigating hypotheses of receptor complex mechanisms resulting from crystal structure analyses.

Activin Receptors↗

Examination of the oncogenic potential of H19 gene in HeLa x normal human fibroblast hybrid cells.

Fusion of tumorigenic HeLa cells with human skin fibroblasts results in chromosomally stable non-tumorigenic hybrids. The studies of rare spontaneous tumorigenic segregants from the non-tumorigenic hybrid have implicated the loss of one copy of human fibroblast chromosome 11 with concomitant re-expression of tumorigenicity. In a previous study of differential display screening, we reported the tumorigenic-specific expression of H19 gene as a possible candidate for elicitation of tumorigenic phenotype. In this study, we examined the expression of H19 gene using gamma-ray-induced tumorigenic mutants (GIMs) and non-tumorigenic irradiated control cells (CONs) from the non-tumorigenic hybrids. H19 expression was recognized in all the GIMs with various expression levels, whereas no CONs expressed the H19 gene. To examine the tumorigenic potentials of H19 gene directly, we introduced an H19 gene expression vector into the non-tumorigenic hybrids and assayed the tumorigenicity of the transfectants by s.c. injection into athymic nude mice. However, no transfectants with stable H19 gene expression induced in vivo tumor growth. These results suggest that expression of the H19 gene may be necessary but is not sufficient to confer the tumorigenic phenotype in HeLa x fibroblast hybrids.

Animals↗

[A case of benign fibrous histiocytoma of the lung in a child].

A case of benign fibrous histiocytoma of the lung in a 8 years old boy was presented. He was first admitted in May, 1983, with recurrent pneumonia. Chest X-ray showed a ill-defined mass in the right lower lobe. Bronchoscopy revealed a round tumor, 1 cm. in maximum diameter, with complete obstruction of the Truncus Intermedius. Endoscopic resection was performed and partial obstruction of the Truncus Intermedius remained. He was re-admitted with pneumonia of the right middle lobe in March, 1986. Bronchoscopy showed severe stenosis of the Truncus Intermedius. Right middle and lower lobectomy was performed. The 4 X 4 X 3 cm tumor was located in the median of the Truncus Intermedius. Microscopically, the lesion composed of fibroblast-like cells and histiocyte-like cells. The patient's post-operative course was uneventful. He has no signs of local recurrence or metastasis. We believe, this is the first reported primary benign fibrous histiocytoma of the lung in a child in Japan.

Bronchial Neoplasms↗

[Use of nuclear magnetic resonance in cranio-facial pathology. Preliminary study].

The use of MRT in craniofacial pathology has been evaluated above all as regards the possibility offered by this technique for studying the soft parts with better results than already sophisticated investigations like the CT scan. The technique's limitations are the long duration of the investigation, the impossibility of carrying it out in carriers of pacemakers, the inadequate visualisation of the bone and calcifications, the fairly high cost; the advantages are the fact that ionising radiation is not employed, the ureter sensitivity for the soft parts, the good vessel evaluation and the possibility of obtaining oriented sections in every space plane without moving the patient. The use of MRT is therefore rich in prospects.

Humans↗

[Clinical and radiological results after cruciate ligament repairs using the meniscus (author's transl)].

The postoperative clinical course and late x-ray results after plastic reconstruction of the cruciate ligament with a meniscus. Presented here are the postoperative results after plastic reconstruction of the anterior cruciate ligament with the medial meniscus. The periods of observation cover up to 29 years. 14 patients were personally re-examined, 3 were accounted for after answering a questionnaire. Only 2 cases showed severe instability and 13 cases gonarthrosis of varying degree. 13 cases were satisfied with the results of the operation. 16 patients were able to maintain their occupations, 5 changed their professions. The majority of patients is involved in athletic activity of wide variety, 6 participate in competitive sports.

Adolescent↗

Molecular structure of bacterial endotoxin (Escherichia coli Re lipopolysaccharide): implications for formation of a novel heterogeneous lattice structure.

Analyses of crystals of Escherichia coli Re lipopolysaccharide (LPS) formed after storage in 1% triethylamine indicate that the LPS molecules are assembled to form a monolayered structure consisting of a novel heterogeneous lattice structure, the greater part of which is occupied by one kind of lattice (lattice I), corresponding to the acyl chain portion of lipid A, and the remainder is occupied by the other kind of lattice (lattice II), corresponding to the 3-deoxy-Dmanno-octulosonic acid (dOclA) dimer and the N-acetylglucosamine disaccharide of lipid A. X-ray diffraction reveals that the type of cell is monoclinic (a = 5.53 A, b = 27.2 A, c = 6.47 A, alpha = 90 degrees, beta = 125.8 degrees, gamma = 90 degrees ). Atomic force microscopy shows that crystals consist of multiple layers; the thickness of a layer corresponds to the b-axis value, and two types of surface topographies are visualized. One, regarded as the view onto the acyl chain ends, is two-dimensional arrays of oval bodies that constitute the lattice, with the lattice constants corresponding to the a- and c-axes and the angle of beta (lattice I). The other, regarded as the view onto the dOclA dimers, is two-dimensional arrays of dromedary-back-like bodies that constitute the lattice with axes of 9.0 and 10.7 A and the angle of 65 degrees formed by both axes (lattice II). Based on these results, we present the molecular model of E. coli Re LPS.

Carbohydrate Conformation↗

MM3 parametrization of four- and five-coordinated rhenium complexes by a genetic algorithm--which factors influence the optimization performance?

Genetic algorithms (GA) were used to solve one of the multidimensional problems in computational chemistry, the optimization of force field parameters. The correlation between the composition of the GA, its parameters (p(c), p(m)) and the quality of the results were investigated. The composition was studied for all combinations of a Simple GA/Steady State GA with a Roulette Wheel/Tournament Selector using different values each for crossover (0.5, 0.7, 0.9) and mutation rates (0.01, 0.02, 0.05, 0.10, 0.20). The results show that the performance is strongly dependent on the GA scheme, where the Simple GA/Tournament Selector yields the best results. Two new MM3 parameters were introduced for rhenium compounds with coordination number four (204) and coordination number five (205), the formal oxidation states of rhenium ranging from +V to +VII. A manifold of parameters (Re-C, N, O, S) was obtained by using a diverse set of CSD structures. The advantage of the GA vs. UFF calculations is shown by comparison of several examples. The GA optimized parameters were able to reproduce the geometrical data of the X-ray structures.

Journal Article↗

Intracellular elemental concentrations in renal tubular cells. An electron microprobe analysis.

In order to be able to examine the processes involved in transepithelial transport in tissues, which are not composed of a single cell type, methods are required, which permit analysis at a cellular level. The technique of electron microprobe analysis permits the intracellular concentrations of many elements to be determined simultaneously in various portions of the cell. The application of this method to renal cortical tissue has shown that the best estimates of the cytoplasmic concentrations are to be obtained in regions close to the nucleus, farthest from the basolateral infoldings and microvilli, which separate the intracellular environment from the extracellular space. The nuclear concentrations of Na and K do not differ from those in the surrounding cytoplasm, although those of P and Cl are somewhat higher in cytoplasm. The intracellular element concentrations in the different cell types vary somewhat, proximal tubular cells contain higher concentrations of Na and Cl and lower ones of P than distal tubular cells. Following ischaemia, a manoeuvre know to result in a disturbance of intracellular electrolytes, Na was observed to rise and K to fall only in the non-surface cells of kidneys exposed to the air, but in all cells, if the kidneys were kept air-free in an atmosphere of N2. The proximal and distal tubular cells showed a variable resistance to ischaemia, the distal tubular cells being much more resistant. Despite the severity of the electrolyte disturbance following ischaemia, the intracellular composition was completely restored one hour after re-introducing renal blood flow.

Animals↗

Sub-atomic resolution crystal structure of cholesterol oxidase: what atomic resolution crystallography reveals about enzyme mechanism and the role of the FAD cofactor in redox activity.

The crystal structure of cholesterol oxidase, a 56kDa flavoenzyme was anisotropically refined to 0.95A resolution. The final crystallographic R-factor and R(free) value is 11.0% and 13.2%, respectively. The quality of the electron density maps has enabled modeling of alternate conformations for 83 residues in the enzyme, many of which are located in the active site. The additional observed structural features were not apparent in the previous high-resolution structure (1.5A resolution) and have enabled the identification of a narrow tunnel leading directly to the isoalloxazine portion of the FAD prosthetic group. The hydrophobic nature of this narrow tunnel suggests it is the pathway for molecular oxygen to access the isoalloxazine group for the oxidative half reaction. Resolving the alternate conformations in the active site residues provides a model for the dynamics of substrate binding and a potential oxidation triggered gating mechanism involving access to the hydrophobic tunnel. This structure reveals that the NE2 atom of the active site histidine residue, H447, critical to the redox activity of this flavin oxidase, acts as a hydrogen bond donor rather than as hydrogen acceptor. The atomic resolution structure of cholesterol oxidase has revealed the presence of hydrogen atoms, dynamic aspects of the protein and how side-chain conformations are correlated with novel structural features such as the oxygen tunnel. This new structural information has provided us with the opportunity to re-analyze the roles played by specific residues in the mechanism of the enzyme.

Binding Sites↗

Localisation of a CSF fistula by metrizamide CT cisternography.

Localisation of a cerebrospinal fluid fistula in the nasal region is difficult. Lack of a suitable roentgen contrast medium for intrathecal use has earlier restricted the utility of cisternography. Metrizamide cisternography and CT have recently proved to be well tolerated and effective in revealing CSF fistulae. A case report of operatively treated CSF rhinorrhea recurring after three years is presented. With the help of CT metrizamide cisternography, the fistula could finally be localised in the sphenoidal sinus. The re-operation confirmed this finding. The technique of cisternography is described.

Aged↗

Effects of 252Cf neutrons, transmitted through an iron block on human lymphocyte chromosome.

Chromosome aberration of human peripheral blood lymphocytes exposed to californium-252 (252Cf) neutrons transmitted through a 15 cm thick iron block was analysed. The spectrum of the filtered neutrons ranged from 0.1 to 2 MeV with a peak at 0.7 MeV, simulating the Hiroshima atomic bomb neutron spectrum as shown in the Dosimetry System 1986 (DS86). Chromosome aberration frequencies after exposure to filtered and unfiltered 252Cf radiation were compared. Acentric ring chromosomes were significantly increased (p < 0.05) in the filtered condition. However, yields of dicentrics and centric rings induced by the filtered neutrons were not statistically different from those induced by the unfiltered neutrons (p > 0.1). The relative biological effectiveness (RBE) of the neutrons with respect to the formation of dicentrics and centric rings was 10.9 and 12.3 in the filtered and unfiltered conditions respectively, but the difference was not statistically significant. These results provide useful information for the re-evaluation of the biological effect of the Hiroshima atomic bomb radiations.

Californium↗

Radiofrequency ablation of arrhythmias guided by non-fluoroscopic catheter location: a prospective randomized trial.

AIMS: To compare the utility of non-fluoroscopic mapping systems (Carto and Ensite NavX) with that of conventional mapping in patients referred for catheter ablation of a wide variety of arrhythmias. METHODS AND RESULTS: Patients referred for catheter ablation (excluding atrial fibrillation, atypical atrial flutter, ventricular tachycardia in structural heart disease, and complete AV nodal ablation) were randomized equally to a procedure guided by Carto, Ensite NavX, or conventional mapping. A total of 145 patients were recruited (82 men, aged 49+/-16, range 18-85). In 19 patients, no ablation was performed, and in the remaining, typical atrial flutter, atrioventricular nodal re-entrant tachycardia, and atrioventricular re-entrant tachycardias [including Wolff-Parkinson-White (WPW)] accounted for 93% of ablations. Overall procedure time, immediate and short-term success, complication rate, and freedom from symptoms at follow-up were identical for all groups. NavX led to the least X-ray exposure: Navx vs. conventional, median (range): 4 (0-50) vs. 13 (2-46) min (P<0.001); NavX vs. Carto, median (range): 4 (0-50) vs. 6 (1-55) min (P=0.008). Both Carto and NavX increased disposable costs by 50% when compared with conventional (P<0.001). For typical atrial flutter, Carto and NavX reduced screening times without increasing procedure cost. If ablation was not performed, NavX was twice as expensive as Carto or conventional. CONCLUSION: Ensite NavX and Carto procedures have similar effectiveness and safety to a conventional approach; however, they both reduce X-ray exposure, with NavX producing a significantly greater effect than Carto. Although this benefit is achieved at a greater financial cost, there may be long-term benefits to catheter laboratory staff.

Arrhythmias, Cardiac↗

Spontaneous rupture of renal tumours: the role of imaging in diagnosis and management.

This study aimed to evaluate whether patients presenting with spontaneous haemorrhage from renal tumours could be accurately diagnosed and initially managed conservatively, and evaluate the role of imaging in guiding the timing and type of subsequent operation. The clinical features, imaging findings and management of seven patients presenting with spontaneous rupture of renal tumour over a 5-year period were reviewed. The information from various imaging studies was evaluated in relation to the subsequent course of intervention. The tumours consisted of six angiomyolipomas and one renal cell carcinoma. In all cases, imaging studies were diagnostic, with computed tomography being the most useful single modality. Emergency surgery was required in one patient for evacuation of suspected infected haematoma and wedge excision of angiomyolipoma. Three elective nephrectomies were performed, while three other patients with ruptured angiomyolipoma were treated conservatively and remained well, without any intervention. In conclusion, patients presenting with spontaneous rupture of renal tumour can be managed conservatively initially. Imaging facilitates accurate pre-operative diagnosis, which was angiomyolipoma in all but one patient in this series. The subsequent intervention can be tailored according to the lesion type and the anticipated risk of re-haemorrhage.

Adult↗