Cellular and subcellular localization of gastrointestinal glutathione peroxidase in normal and malignant human intestinal tissue

The gastrointestinal glutathione peroxidase (GI-GPx) is believed to prevent absorption of hydroperoxides. GI-GPx is expressed in the intestine together with the other three glutathione peroxidase isoenzymes, raising the question of the physiological role of the different GPx types. We therefore studied the cellular and subcellular distribution of GI-GPx in normal and malignant tissue obtained from patients with colorectal cancer or familial polyposis by immunohistochemistry. In healthy ileum epithelium GI-GPx was preferentially enriched in Paneth cells. In unaffected crypts of colon and rectum, it decreased gradually from the ground to the luminal surface. In crypt ground, GI-GPx was uniformly distributed, whereas in cells at the luminal surface it was concentrated in structures capping the nuclei at the apical pole. In colorectal cancer, GI-GPx expression depended on the stage of malignant transformation. In early stages, GI-GPx was increased and pronouncedly associated with the vesicular structures. In progressed stages of malignancy, structures disintegrated and GI-GPx distribution became more diffuse. These observations support the hypothesis that GI-GPx, apart from being a barrier against hydroperoxide absorption, might be involved in cell growth and differentiation.     

Forelimb skeletal morphology and flight mode evolution in pelecaniform birds

The total length and mid-shaft diameters of wing elements of 50 species of pelecaniform birds were examined to investigate how forelimb skeletal morphology varies with body size and flight mode within this group. Pelecaniforms were assigned to flight mode categories based on primary habitual behaviors (soar, flap–glide, continuous flap). Allometric and discriminant function analyses were conducted on wing element variables in both historical (using independent contrasts) and ahistorical contexts. Results of this study indicate that when phylogenetic relationships are taken into account, only the length of the ulna scales with positive allometry, whereas all other variables exhibit isometry. These results differ from the ahistorical allometric analysis. Discriminant function analysis (DFA) significantly separated the flight mode groups (Wilk's λ=0.002, p<0.00001), with only six individuals from two species (out of n=284) misclassified. Results of historical canonical variates analysis supported the ahistorical DFA and identified two carpometacarpal (CMC) variables as important for separating the flight mode groups: dorsoventral CMC diameter and total CMC length. The carpometacarpus is that portion of the forelimb skeleton that serves as the attachment point for the primary flight feathers, and thus, that portion of the airfoil surface that mediates detailed flight control. Its morphology, more than any other element, reflects differences in flight mode in pelecaniforms. Results of this study indicate that, in pelecaniforms, wing bones generally exhibit isometry (with the exception of the ulna) and do possess specific morphologies reflective of the demands associated with different types of aerial locomotor specialization.     

Influence of HLA DRB1 alleles in the susceptibility of rheumatoid arthritis and the regulation of antibodies against citrullinated proteins and rheumatoid factor

Introduction  

The purpose of this study was to investigate the association between HLA-DRB1 alleles with susceptibility to rheumatoid arthritis (RA) and production of antibodies against citrullinated proteins (ACPA) and rheumatoid factor (RF).     

The complexity of the Rab and Rho GTP-binding protein subfamilies revealed by a PCR cloning approach.

Partial sequences corresponding to eleven novel Rab proteins and one new Rho protein have been isolated using a PCR-based cloning approach. These results confirm that the overall diversity of the Rab and Rho protein subfamilies account for more than thirty different members in mammalian cells.     

Evidence for nuclear and DNA binding forms of the receptor-glucocorticoid complex from hepatoma tissue culture cells.

Binding to DNA associated with cellulose has been used to investigate the receptor-glucocorticoid complex isolated from a line of rat hepatoma tissue culture cells. The amount of activated complex that bound to DNA was approximately half that which bound to nuclei. Additional results suggest the existence of two forms of the activated glucocorticoid receptor-steroid complex in about equal amounts: one form binds only to nuclei and the other binds to DNA and nuclei. The two forms also differ in their stability, with the DNA/nuclei binging form being relatively labile. The binding of either form to the appropriate acceptor is reduced by cytosol inhibitors by the same mechanism.     

Identification of an Inhibitory Element within the Human 68-kDa (U1) Ribonucleoprotein Antigen

Various nuclear proteins are the major targets of autoimmune responses in various rheumatic disorders. In particular, autoantibodies directed against a 68-kDa protein associated with the (U1) RNA-containing small nuclear ribonucleoprotein complexes typically occur in sera of patients with mixed connective tissue disease and related rheumatic disorders, such as systemic lupus erythematosus, and therefore are very useful as a serological marker. For establishing powerful immunoassays, it was necessary to generate recombinant human P68 antigen as the antigenic target. In this study we demonstrated that the cDNA coding for the full-length human P68 antigen could not be expressed by a traditional bacterial vector system due to a putative inhibitory sequence designated as inhibitory sequence X which is located between the autoreactive domains C′ and D′ of the human P68 antigen. The construction of corresponding hybrid plasmids carrying two functional and independent gene blocks indicated thetrans-active function of the inhibitory sequence X, which could be localized by expression studies of various deletion constructs. Comparable Northern blot analysis clearly demonstrated that the inhibitory sequence X could act on the translation of the P68 mRNA. After excision of the inhibitory sequence X a dramatic increase in the production of recombinant human P68 antigen was observed.     

The ecology of oligocene African anthropoidea

African anthropoids are first recorded in Early Oligocene deposits of the Fayum Province, Egypt. Six genera and nine species are recognized. Estimated body weights for these taxa are based on the regression equation log ₁₀(B) = 2.86log ₁₀(L) + 1.37, whereB is the bodyweight in grams, and Lis the M ₂ length in millimeters. The equation is derived from 106 species of living primates. Fayum species range in body weight from about 600 g (Apidium moustafai)to about 6000 g (Aegyptopithecus zeuxis).A similar range of body weight is found among extant Cebidae. The Fayum primates are larger than any extant insectivorous primates;this fact probably rules out a predominantly insectivorous diet. Extant frugivorous hominoids can be separated from folivorous hominoids on the basis of molar morphology. Folivorous apes (gorilla and siamang) have proportionately more shearing on their molars than do frugivorous species. Based on the hominoid analogy, the molar morphology of the Fayum species is consistent with a frugivorous diet. Parapithecus grangeristands apart from other Fayum species in having better developed molar shearing, possibly indicating that it had more fiber in its diet. Terrestrial species of Old World monkeys tend to have significantly higher molar crowns than do more arboreal species. This difference may relate to an increased amount of grit in the diet of the more terrestrial species, selecting for greater resistance to wear. Oligocene primates have molar crown heights consistent with a primarily arboreal mode of existence. However, the particularly high molar crowns of Parapithecus grangerisuggest that this species may have foraged on the ground to a considerable degree. Other evidence is advanced suggesting that Apidiummay have had a diurnal activity pattern.