Objective. To determine the integrity of the hypothalamic-pituitary-adrenal (HPA) axis responses to immune/inflammatory stimuli in patients with rheumatoid arthritis (RA).Methods. Diurnal secretion of cortisol and the cytokine and cortisol responses to surgery were studied in subjects with active RA, in subjects with chronic osteomyelitis (OM), and in subjects with noninflammatory arthritis, who served as controls.Results. Patients with RA had a defective HPA response, as evidenced by a diurnal cortisol rhythm of secretion which was at the lower limit of normal in contrast to those with OM, and a failure to increase cortisol secretion following surgery, despite high levels of interleukin-Ijl (IL-lm and IL-6. The corticotropinreleasing hormone stimulation test in the RA patients showed normal results, thus suggesting a hypothalamic defect, but normal pituitary and adrenal function.Conclusion. These findings suggest that RA patients have an abnormality of the HPA axis response to
Loss of tight association between epidermis and dermis underlies several blistering disorders and is frequently caused by impaired function of extracellular matrix (ECM) proteins. Here we describe a new protein in mouse, Fras1, that is specifically detected in a linear fashion underlying the epidermis and the basal surface of other epithelia in embryos. Loss of Fras1 function results in the formation of subepidermal hemorrhagic blisters as well as unilateral or bilateral renal agenesis during mouse embryogenesis. Postnatally, homozygous Fras1 mutants have fusion of the eyelids and digits and unilateral renal agenesis or dysplasia. The defects observed in Fras1-/- mice phenocopy those of the existing bl (blebbed) mouse mutants, which have been considered a model for the human genetic disorder Fraser syndrome. We show that bl/bl homozygous embryos are devoid of Fras1 protein, consistent with the finding that Fras1 is mutated in these mice. In sum, our data suggest that perturbations in the composition of the extracellular space underlying epithelia could account for the onset of the blebbed phenotype in mouse and Fraser syndrome manifestation in human.
Pax6 is a key regulator of eye development in vertebrates and invertebrates, and heterozygous loss-of-function mutations of the mouse Pax6 gene result in the Small eye phenotype, in which a small lens is a constant feature. To provide an understanding of the mechanisms underlying this haploinsufficient phenotype, we evaluated in Pax6 heterozygous mice the effects of reduced Pax6 gene dosage on the activity of other transcription factors regulating eye formation. We found that Six3 expression was specifically reduced in lenses of Pax6 heterozygous mouse embryos. Interactions between orthologous genes from the Pax and Six families have been identified in Drosophila and vertebrate species, and we examined the control of Pax6 and Six3 gene expression in the developing mouse lens. Using in vitro and transgenic approaches, we found that either transcription factor binds regulatory sequences from the counterpart gene and that both genes mutually activate their expression. These studies define a functional relationship in the lens in which Six3 expression is dosage-dependent on Pax6 and where, conversely, Six3 activates Pax6. Accordingly, we show a rescue of the Pax6 haploinsufficient lens phenotype after lensspecific expression of Six3 in transgenic mice. This phenotypic rescue was accompanied by cell proliferation and activation of the platelet-derived growth factor ␣-R͞cyclin D1 signaling pathway. Our findings thus provide a mechanism implicating gene regulatory interactions between Pax6 and Six3 in the tissue-specific defects found in Pax6 heterozygous mice.homeodomain proteins ͉ transcription factors ͉ eye development
Little is known about the genetic control of preimplantation development. We have isolated, characterized, and mutated a previously undescribed mouse gene, Traube (Trb), essential for preimplantation development. Similar protein coding sequences are found in rats, humans, and yeast. The TRB protein contained two amino-terminal acidic domains, a leucine zipper, and three putative nuclear localization signals. The Trb gene was expressed at low levels ubiquitously early in development and became restricted to the liver and the central nervous system from E11.5 onward. Myc-tagged TRB protein was localized to the nucleus, and in a large proportion of the cells to the nucleoli. The Trb mutant embryos halted in development at the compacted morula stage at E2.5. At E3.5 they started to decompact and a day later they disintegrated and died. The observed defect was cell autonomous, as mutant cells failed to participate in the formation of chimeric embryos. The Trb mutant embryos showed a 50% reduction of the total cell number. The mutant embryos exhibited a paucity of ribosomes, polyribosomes, and rough endoplasmic reticulum. This paucity of ribosomes together with the localization of TRB to the nucleoli, the site of ribosome synthesis, suggests that TRB is involved in the synthesis of ribosomes.
Familial Mediterranean Fever (FMF) is an autosomal recessive disease of high prevalence within Mediterranean countries and particularly common in four ethnic populations: Arabs, non-Ashkenazi Jews, Armenians, and Turks. The responsible gene MEFV has been assigned to chromosome 16p13.3. Our aim was to establish the frequencies of the most common mutations in Greek-Cypriots. We found that 1 in 25 is a carrier of one of three mutations. V726A, M694V, and F479L. In 68 Grek-Cypriot FMF chromosomes analyzed, we found V726A (25%), F479L (20.6%), M694V (17.6%), and others (36.8%). Mutation F479L, relatively common in this population, is very rare elsewhere. Our study indicates that FMF is not a rare condition in Cyprus and that, because of the significant morbidity associated with this disorder, which is often diagnosed only after unnecessary surgeries, a newborn screening program to detect affected in this population may be warranted.
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