Langerhans' cell histiocytosis and juvenile xanthogranuloma of the orbit. Clinicopathologic, CT, and MR imaging features

The clinical, radiologic, and histopathologic features of two main disorders of the orbit are discussed. Group I, Langerhans cell histiocytosis (histiocytosis X, Class I), is caused by proliferation of X histiocytic Langerhans' cells. Group II is juvenile xanthogranuloma, and Class II is related to the proliferation of non-X histiocytic (monocyte-macrophage) cells. The two diseases are of unknown cause and differ in their clinical, radiologic, and histopathologic features.     

Synthesis and biological activities of phenyl piperazine-based peptidomimetic growth hormone secretagogues

A new class of potent, orally active phenyl piperazine-based GH secretagogues have been discovered from attempts to mimic the arrangement of the phenyl substituent in the spiroindanyl piperidine and spiroindoline sulfonamide privileged structures of 4 and 1, respectively. The best of these compounds, 18 (EC50 = 2.8 nM) is nearly as potent as MK-0677 for releasing GH from rat pituitary cells.     

EAE TCR motifs and antigen recognition in myelin basic protein-induced anterior uveitis in Lewis rats

T cells infiltrating the iris/ciliary body of Lewis rats with anterior uveitis (AU) that had been induced by myelin basic protein (MBP) immunization were previously found to share surface markers common to the T cells that cause experimental autoimmune encephalomyelitis (EAE). To determine whether these AU-associated T cells are in fact the same as those that infiltrate the central nervous system to cause EAE, we examined TCR V gene expression in T cells infiltrating the anterior chamber in rats with AU. As with EAE, we found a biased expression of Vbeta8.2 and Valpha2 in the iris/ciliary body and, although one would expect an influx of nonspecific inflammatory T cells, these biases were still evident at the peak of AU. An analysis of the TCR Vbeta8.2 and Valpha2 sequences derived from the iris/ciliary body demonstrated the presence of the same complementarity determining region 3 motifs found in MBP-specific T cells that are pathogenic for EAE and found in T cells derived from the central nervous system of rats with EAE. Finally, T cells isolated from the iris/ciliary body of rats with AU were found to proliferate in a specific fashion to MBP Ags. Thus, it appears that MBP-specific T cells are pathogenic for AU as well as EAE in the Lewis rat. In addition, the long-term presence of this highly restricted MBP response in the iris/ciliary body indicates that distinct immunoregulatory mechanisms exist in the environment of the eye. This provides an interesting model with which to address questions pertaining to the nature of T cells infiltrating the eye and their regulation during EAE and other systemic diseases.     

The use of enzymes in treating patients with malignant lymphoma with a large tumor mass]

Systemic enzymes (wobenzime and wobe-mugos) were approved, that had been prescribed as part of polychemotherapy to 24 patients with malignant lymphomas, who presented with large masses of lymphatic nodes poorly resorbable against the background of polychemotherapy and who were assigned for a high-total dose irradiation, which fact would undoubtedly entail sclerosing of adjacent intact tissues. The use of the enzymes made for the optimum realization of the polychemotherapy effect and permitted avoiding a good many of undesirable side events and complication thereof. The above systemic enzymes are well tolerated by patients; they induce no significant changes in the cellular composition or in blood biochemical indices.     

Effect of dopants on the performance of CuO–CeO2 catalysts in methanol steam reforming

Steam reforming of methanol was carried out over a series of doped CuO–CeO₂ catalysts prepared via the urea–nitrate combustion method. XRD analysis showed that at least part of the dopant cations enter the ceria lattice. The addition of various metal oxide dopants in the catalyst composition affected in a different way the catalytic performance towards H₂ production. Small amounts of oxides of Sm and Zn improved the performance of CuO–CeO₂, while further addition of these oxides caused a decrease in catalyst activity. XPS analysis of Zn- and Sm-doped catalysts showed that increase of dopant loading leads to surface segregation of the dopant and decrease of copper oxide dispersion. The addition of oxides of La, Zr, Mg, Gd, Y or Ca lowered or had no effect on catalytic activity, but led to less CO in the reaction products. Noble-metal modified catalysts had slightly higher activity, but the CO selectivity was also significantly higher.     

Purification, characterization, and high performance liquid chromatography assay of Salmonella glucose-1-phosphate cytidylyltransferase from the cloned rfbF gene

We report the purification and characterization of glucose-1-phosphate cytidylyltransferase, the first of five enzymes committed to biosynthesis of CDP-D-abequose from Salmonella enterica strain LT2. The purification was greatly facilitated by using a cloned rfbF gene encoding this enzyme. Pure enzyme was obtained by 64-fold enrichment in three chromatography steps. The NH2-terminal sequence of the purified enzyme was in agreement with the sequence predicted from the nucleotide sequence of the rfbF gene. The SDS-polyacrylamide gel electrophoresis estimated subunit M(r) of 31,000 agrees well with the M(r) of 29,035 calculated from the amino acid composition deduced from the nucleotide sequence of the rfbF gene. The glucose-1-phosphate cytidylyltransferase catalyzes a reversible bimolecular group transfer reaction and steady-state kinetic measurements, including product inhibition patterns, indicate that this reaction proceeds by a "ping-pong" type of mechanism. The Km values for CTP, alpha-D-glucose 1-phosphate, CDP-D-glucose, and pyrophosphate are 0.28, 0.64, 0.11, and 1.89 mM, respectively.     

A critique of the application of sensory integration therapy to children with learning disabilities

Sensory integration (SI) therapy is a controversial--though popular--treatment for the remediation of motor and academic problems. It has been applied primarily to children with learning disabilities, under the assumption that such children (or at least a subgroup of them) have problems in sensory integration to which some or all of their learning difficulties can be ascribed. The present article critically examines the related issues of whether children with learning disabilities differentially exhibit concomitant problems in sensory integration, and whether such children are helped in any way by means specific to SI therapy. An overview of theoretical contentions and empirical findings pertaining to the first issue is presented, followed by a detailed review of recent studies in the SI therapy research literature, in an effort to resolve the second issue. Results of this critique raise serious doubts as to the validity or utility of SI therapy as an appropriate, indicated treatment for the clinical population in question--and, by extension, for any other groups diagnosed as having "sensory integrative dysfunction." It is concluded that the current fund of research findings may well be sufficient to declare SI therapy not merely an unproven, but a demonstrably ineffective, primary or adjunctive remedial treatment for learning disabilities and other disorders.