Peptide secretory pathways in GI tract: cytochemical contributions to regulatory physiology of the gut

Numerous biologically active peptides are produced by specialized cells of the gastrointestinal tract. Most of these peptides are also produced outside the gut, and current evidence suggests that they not only regulate digestive events per se but also participate in many other regulatory mechanisms working as hormonal, paracrine, and neuronal messengers. The physiological functions of the gastrointestinal peptides are yet very incompletely known. Immunocytochemical tracing of the destinations of neuronal and paracrine cell processes may, together with available physiological and biochemical data, provide valuable clues to the sites of actions of many of the novel regulatory peptides. Moreover, immunocytochemistry has given evidence for the occurrence of multiple secretory peptides in certain endocrine cell types and suggested that certain peptides simultaneously may be secreted by multiple endocrine, paracrine, and neural cell types. This review emphasizes the continued need for concerted cytochemical, physiological, and biochemical studies of the sites of synthesis, secretion, and action of gastrointestinal regulatory peptides.     

Connective tissue growth factor expression and Smad signaling during mouse heart development and myocardial infarction.

Connective tissue growth factor (CTGF) is reported to be a target gene of transforming growth factor beta (TGFbeta) and bone morphogenetic protein (BMP) in vitro. Its physiological role in angiogenesis and skeletogenesis during mouse development has been described recently. Here, we have mapped expression of CTGF mRNA during mouse heart development, postnatal adult life, and after experimental myocardial infarction. Furthermore, we investigated the relationship between CTGF and the BMP/TGFbeta signaling pathway in particular during heart development in mutant mice. Postnatally, CTGF expression in the heart became restricted to the atrium. Strikingly, 1 week after myocardial infarction, when myocytes have disappeared from the infarct zone, CTGF and TGFbeta expression as well as activated forms of TGFbeta but not BMP, Smad effector proteins are colocalized exclusively in the fibroblasts of the scar tissue, suggesting possible cooperation between CTGF and TGFbeta during the pathological fibrotic response.     

Trisomy 8 as the sole chromosomal aberration in myelocytic malignancies: a multicolor and locus-specific fluorescence in situ hybridization study

Trisomy 8 is the most common chromosomal aberration in myelocytic malignancies, occurring both as a sole change as well as in addition to other abnormalities. In spite of this, next to nothing is known about its pathogenetic importance or its molecular genetic consequences. Possible mechanisms involved in the transformation process include dosage effects of genes mapping to chromosome 8 and presence of specific mutations or cryptic fusion genes on the duplicated chromosome. In the latter case, +8 would be secondary to a cryptic primary rearrangement and not involved in leukemogenesis as such, but rather in tumor evolution. Although hidden genetic changes have been found in some trisomies, for example, mutations in KIT in acute myelocytic leukemia (AML) with +4 and in MET in hereditary papillary kidney carcinoma with trisomy 7, none associated with +8 have so far been discovered. To address this issue, we have investigated a total of 13 cases of AML, myelodysplastic syndromes, and chronic myeloproliferative disorders with trisomy 8 as the sole chromosomal anomaly. All cases were studied by combined binary ratio multicolor fluorescence in situ hybridization (FISH) and with FISH using locus-specific probes for both arms of chromosome 8, the subtelomeric regions of 8p and 8q, and the leukemia-associated genes FGFR1, MOZ, ETO, and MYC. No cryptic changes were detected, thus excluding the possibility of gross genetic rearrangements or aberrations involving these loci on chromosome 8.     

A functionally active complement system is present in uterine secretion of the mouse prior to implantation.

Sephadex beads were placed carefully in the uterus on days 2 and 3 and left for 6 to 8 h to absorb uterine secretion. The beads were then removed with volatile silicon oil and mounted on small pieces of nitrocellulose paper. Immuno-staining of these bead blots showed they contained the complement components C1q, C3, C4, and C5. We demonstrated that complement component C3 in the uterine secretion could be activated and deposited on model immune complexes, and also that antibody-coated erythrocytes were lysed in utero, that is, a membrane attack complex was produced. Thus, the mouse uterine secretion at the preimplantation stage contains a functionally active complement system.     

Regulation by T cells of delayed hypersensitivity reaction in mouse lung as reflected by mononuclear cells, mast cells and mucus-producing cells

The appearance of mononuclear cells, mast cells and mucus-producing cells in the lung and their linkage to the development of delayed hypersensitivity (DH) reactions were studied. Adoptive transfer of immune lymph node cells, spleen cells and serum and in vivo treatment with monoclonal antibodies to L3T4-positive T cells in Balb/c mice were performed to investigate the cellular regulation of the number of mononuclear cells, mast cells and mucus-producing cells in the lung. Immune lymph node cells and, to a lesser extent, immune spleen cells from mice sensitized epicutaneously with picrylchloride transferred DH reactions to the recipients as assessed by ear thickness increase after challenge. Serum from sensitized mice was not able to transfer a DH reaction. Cyclophosphamide treatment of donor mice increased the DH reaction in the recipient mice. Adoptive transfer of immune lymph node cells and spleen cells gave a slight increase in the number of mononuclear cells in the lung of recipient mice compared with controls. This weak accumulation of mononuclear cells in the lungs of recipient mice, however, was not accompanied by a consistent increase in the number of mucus-producing cells and mast cells. The number of spleen cells expressing the L3T4 antigen decreased after in vivo treatment with the monoclonal GK1.5 (anti-L3T4) antibody as assessed by immunohistochemistry. This antibody treatment also resulted in an inhibition of the DH reaction and a decrease in the number of mononuclear cells and mucus-producing cells, but not in mast cells in the lung of sensitized and challenged mice.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antibody response in laying hens with small amounts of antigen

Chicken antibodies offer many advantages over the traditional mammalian ones. A laying hen produces large amounts of yolk antibodies and the use of yolk antibodies eliminates the painful procedure of collecting blood from the animal. Thus, the use of chicken antibodies will reduce both the number of animals required to produce antibodies and also animal distress. Chicken antibodies also have several biochemical advantages compared to mammalian antibodies: they often increase the signal and reduce interference in many assays. However, the species chosen for antibody production have usually been mammals. This is probably due to tradition, but also to limited knowledge about the production of chicken antibodies. We studied the immune response in the chicken using small amounts of mammalian antigen, and show that a good immune response can be obtained with 0.1–1.0 μg of bovine serum albumin.     

Novel latex agglutination method with chicken anti-protein A for detection of Staphylococcus aureus infections.

A latex agglutination assay for the detection of protein A-secreting Staphylococcus aureus strains or strains with protein A in the cell wall is described. The assay utilizes latex particles coated with chicken anti-protein A antibodies. Chicken antibodies do not react with protein G-producing streptococci or rheumatoid factor, thus avoiding false-positive reactions.