Hepatic nuclear and cytoplasmic effects following intermittent feeding of rats with di(2-ethylhexyl) phthalate

The effects on rats of intermittent feeding with the peroxisome proliferator and hepatocarcinogen di(2-ethylhexyl) phthalate (DEHP) have been examined. Male Wistar rats were fed for alternate 7-day periods diets containing 20,000 ppm DEHP or the control diet. The rats were examined 3 days after the start or recommencement of administration of the DEHP-containing diet or after 7 days on the control diet. After the commencement or recommencement of feeding with DEHP the expected increases in liver weight and in the number of peroxisomes were found. The increase in liver: body-weight ratio in response to administration of DEHP-containing diets was greater in rats that had been previously exposed to the compound, but re-administration of DEHP had a less marked effect on the increase in peroxisome number. Morphometric analysis showed that administration of DEHP-containing diets resulted in an increase in cell number in the liver and that a fall in the cell number occurred after the rats had been returned to the control diet for 7 days. Analysis of nuclear size gave results consistent with an increase in tetraploid hepatocytes after treatment with DEHP which was reversed when the rats were returned to control diet.     

Epidermal growth factor receptor regulates normal urothelial regeneration

Members of the epidermal growth factor (EGF) family and their receptors are involved in many cellular processes, including proliferation, migration, and differentiation. We have previously reported that these growth factors are expressed and have specific regulatory functions in an organ-like culture model of normal human urothelial cells. Here, we used this model to investigate the involvement of EGF receptor (EGFR) in human urothelial regeneration. Three 4-mm-diameter damaged areas were made in confluent normal human urothelial cell cultures with a biopsy punch. Regeneration was measured, on fixed stained cultures, with an image analyzer, at 4, 24, and 48 hours after injury. Cell proliferation was assessed by 5-bromo-2-deoxyuridine incorporation. To identify EGF family factors potentially involved in the healing process, we studied the effect of these factors on damaged confluent cultures and the level of expression of mRNAs extracted from these cultures. EGFR inhibition of the proliferation and migration of urothelial cells was tested with (1). a specific tyrosine kinase inhibitor (AG1478) and (2). a blocking anti-EGFR antibody (LA22). Exogenously added amphiregulin, EGF, transforming growth factor-alpha and heparin-binding EGF (HB-EGF) stimulated urothelial regeneration. The damaged areas were repaired by regrowth within 48 hours. Both AG1478 and LA22 inhibited the repair (by 50% and 30%, respectively), as well as proliferation and migration. This regeneration was accompanied by increased HB-EGF mRNA expression in cultures of cells from four of six subjects, but no corresponding change in EGFR protein level was observed. These results indicate that the EGFR signaling pathway is involved in urothelial regeneration. Our data support an autocrine role of HB-EGF in this process and suggest that the EGFR pathway is a potential therapeutic target for modulating urothelial cell proliferation.     

Die Cercarienfauna der Umgebung von Münster (westf.) und der experimentell ermittelte Individualcyclus von Echinoparyphium spiniferum La Valette (Trematoda)

Ohne ZusammenfassungMit 8 Textabbildungen in 21 Einzeldarstellungen     

Production of pemphigus antibodyin vitro and analysis of T-cell subsets

T cells from nine patients in the active stage of pemphigus vulgaris and five in the inactive stage of the disease were studied with Leu-1, Leu-2, and Leu-3 monoclonal antibodies. No significant differences were observed in the proportions of total T cells or T cells expressing either helper or suppressor phenotype in peripheral blood leukocytes of patients compared to normal subjects. Immunoregulatory mechanisms were functionally studied using an assay measuring total IgG synthesizedin vitro. Peripheral blood leukocytes were separated into T- and B-cell fractions and cultured in various combinations. In nine experiments, the T cells were irradiated prior to culturing with B cells to remove their suppressor function. No statistically significant differences were observed in the total IgG synthesized by B cells obtained from patients and normal subjects when cultured with untreated T cells or irradiated T cells obtained from patients or normal controls. These results indicated that there was no loss of suppressor-cell function or increased helper-cell function when assessed by measuring the total IgG synthesized. The addition of serum from pemphigus patients to peripheral blood leukocyte cultures of pemphigus patients and normal controls had no statistically significant effect on the synthesis of total protein or on the amount of Ig synthesized and secreted. Peripheral blood leukocytes from six untreated patients with pemphigus vulgaris were stimulatedin vitro with pokeweed mitogen (PWM) to produce immunoglobulin. The IgG produced selectively bound to the intercellular cement substance of the epidermis of patients' perilesional skin, normal human skin, and monkey esophagus. The IgG was biosynthetically labeled by culturing the leukocytes in medium supplemented with [³H]leucine, and the binding of the radiolabeled IgG was visualized by autoradiography. The IgG nature of the protein was demonstrated by precipitation withStaphylococcus protein A and removal with rabbit anti-human IgG antisera. Peripheral blood leukocytes obtained from normal volunteers and control patients did not produce this antibody. Our studies indicate that there was no general functional or phenotypic alteration of suppressor or helper T cells in the peripheral blood. The peripheral blood leukocytes of pemphigus patients under PWM stimulation can produce an anti-intercellular cement substance antibodyin vitro. These results indicate that the abnormality of immunoregulation which resulted in the production of a pathogenetic autoantibody in pemphigus is highly specific.     

Demonstration of Antigenic Sites in Glomeruli of Patients with Acute Poststreptococcal Glomerulonephritis by Immunofluorescein and Immunoferritin Technics

The presence and localization of antigenic sites in glomeruli of 14 patients with acute poststreptococcal glomerulonephritis (AGN) were studied by immunofluorescein and immunoferritin technics. Labeled IgG fractions from the same patients were used for the identification of antigenic sites. The staining capacity of these IgG fractions depended on the time when sera were obtained. Staining was minimal during the first week, and increased up to the fourth or fifth week. Glomeruli, however, stained only when renal tissue was obtained during the early phase of the disease. Precise localization of antigenic sites was determined with ferritin-conjugated patients' IgG. Segmental deposition of ferritin was observed in the mesangial matrix and on the endothelial side of the glomerular basement membrane. Subepithelial electron-dense deposits contained no or very few ferritin particles. In contrast, ferritin-conjugated antihuman IgG was distributed diffusely in the mesangial matrix, on the endothelial side of the basement membrane and in subepithelial deposits. These findings suggest that, during the early stage of acute poststreptococcal glomerulonephritis, free antigen is present in the glomeruli of patients with this disease.     

Novel mechanism of tumorigenesis: increased transforming growth factor-beta 1 suppresses the expression of connexin 43 in BALB/cJ mice after implantation of poly-L-lactic acid

Poly-L-lactic acid (PLLA) is a widely used promising material for surgical implants such as tissue-engineered scaffolds. In this study, we aimed to determine the in vivo effect of PLLA plates on the cellular function of subcutaneous tissue in the two mouse strains, BALB/cJ and SJL/J, higher and lower tumorigenic strains, respectively. Gap-junctional intercellular communication (GJIC) and the expression of connexin 43 (Cx43) protein were significantly suppressed, whereas the secretion of transforming growth factor-beta 1 (TGF-beta 1) level was significantly increased in PLLA-implanted BALB/cJ mice compared with BALB/cJ controls. However, no significant difference in TGF-beta 1 secretion was observed between the SJL/J-implanted and SJL/J control mice. We found for the first time that a significant difference was observed between the two strains; thus, the PLLA increased the secretion of TGF-beta 1 and suppressed the mRNA expression of Cx43 at the earlier stage after implantation into the higher-tumorigenic strain, BALB/cJ mice. This novel mechanism might have a vital role in the inhibition of GJIC and promote the tumorigenesis in BALB/cJ mice.