Hippocampal NMDA receptor mRNA undergoes subunit specific changes during developmental lead exposure

The N-methyl- -aspartate (NMDA) receptor has shown to play an important role in the cognitive deficits associated with developmental lead (Pb) exposure. In this study, we examined the effects of low-level Pb exposure on NMDA receptor subunit gene expression in the developing rat brain. The pattern of NR1, NR2A, NR2B, and NR2C subunit mRNA in situ hybridization was consistent with previous studies. Brain levels of NR1 and NR2A mRNAs were lowest shortly after birth, increasing to reach peak levels by 14 or 21 days of age and subsequently decreasing at 28 days of age. NR2B mRNA levels were highest during early development and decreased as the animals aged. NR2C subunit mRNA was restricted to the cerebellum and a signal was not detectable until the second week of life. Lead exposure resulted in significant and opposite effects in NR1 and NR2A subunit mRNA expression with no changes in NR2B or NR2C subunit expression. The Pb-induced changes in NR1 and NR2A subunit mRNA were mainly present in the hippocampus. Hippocampal NR1 mRNA levels were significantly increased in the CA1 (15.3%) and CA4 (26.8%) pyramidal cells from 14-day-old Pb-exposed rats. At 21 days of age, only the NR1 mRNA at the CA4 subfield remained significantly elevated (10.3%). Lead exposure caused reductions of NR2A mRNA levels (11.9–19.3%) in the pyramidal and granule cell layers of the hippocampus at 14 and 21 days of age. NR1 mRNA levels were also significantly increased (14.0%) in the cerebellum of 28-day-old rats with no change in NR2A mRNA at any age. No significant changes in subunit mRNA levels were present in cortical or subcortical regions at any age. The Pb-induced changes in hippocampal NMDA receptor subunit mRNA expression measured in the present study may lead to modifications in receptor levels or subtypes and alter the development of defined neuronal connections which require NMDA receptor activation.     

Differential regulation of cytokine genes in gingival epithelial cells challenged by Fusobacterium nucleatum and Porphyromonas gingivalis

IL-8 mRNA in human gingival epithelial cells (HGECs) is up-regulated by Fusobacterium nucleatum, and up-/down-regulated by Porphyromonas gingivalis in a complex interaction in the early stages (< or = 4 h) after infection. The mechanisms involved in this regulation in response to F. nucleatum and/or P. gingivalis infection, and identification of co-regulated cytokine genes, are the focus of this investigation. Heat, formalin or protease treatment of F. nucleatum cells attenuated the IL-8 mRNA up-regulation. NF-kappaB, mitogen-activated protein kinase (MAPK) p38 and MAPK kinase/extracellular signal-regulated kinase (MEK/ERK) pathways were involved in IL-8 mRNA induction by F. nucleatum. Pretreatment of P. gingivalis with heat, formalin or protease enhanced IL-8 mRNA induction. NF-kappaB, MARK p38, and MEK/ERK pathways were also involved in this induction. In contrast, down-regulation of IL-8 mRNA by P. gingivalis involved MEK/ERK, but not NF-kappaB or MAPK p38 pathways. cDNA arrays analysis revealed that mRNA down-regulation by P. gingivalis is a specific reaction that only a number of genes, e.g. IL-1beta, IL-8, macrophage inflammatory protein-2alpha, and migration inhibitory factor-related protein-14, are affected based on examination of 278 cytokine/receptor genes. These data indicate that F. nucleatum and P. gingivalis trigger specific and differential gene regulation pathways in HGECs.     

20q13.2 Amplification in intraductal hyperplasia adjacent to in situ and invasive ductal carcinoma of the breast

The 20q13 region harboring recently described putative oncogenes is frequently amplified in invasive ductal carcinoma (IDC). The aim of this study was to examine the 20q13 copy number in intraduct hyperplasia (IH), atypical duct hyperplasia (ADH), and ductal carcinoma in situ (DCIS) adjacent to IDC. In 5 patients, comparative genomic hybridization (CGH) after laser microdissection revealed 20q13 amplification in four of five cases of IH, in all of three cases of IH with atypia, all five of DCIS, and all five of IDC. Fluorescence in situ hybridization (FISH) confirmed the amplification at 20q13.2 in IH in the two specimens analyzed. The amplification rate, however, was higher in DCIS and IDC. In phenotypically normal ductal epithelium normal values were found for 20q13 copy number by FISH (n=2) and CGH (n=5). Although the number of cases presented here is small, our results suggest that mutations in the 20q13.2 region in IH may be associated with accelerated proliferation and hyperplasia of the ductal epithelium. Progression to DCIS and ICD is accompanied by a further increase in the 20q13.2 copy number. Received: 17 March 1999 / Accepted: 22 June 1999     

Antigen-Induced Activation of Hypothalamic Cells (assessed by expression of the c-fos gene)

The aim of the present work was to study the activation of the expression of the c-fos gene (by in situ hybridization) in cells from rat (Sprague Dawley) hypothalamic structures 0.5, 2, 6, and 16 h after i.v. injections of tetanus toxoid (200 g/kg). Tetanus toxoid was selected as the antigen because it does not induce any general non-specific body reactions. Control animals received i.v. doses of apyrogenic physiological saline. The number of c-fos mRNA-positive cells in all the hypothalamic structures studied was insignificant 30 min after injections of tetanus toxoid. c-fos mRNA-positive cells were seen in the posterior, lateral, and anterior hypothalamic fields and in the dorsomedial and ventromedial hypothalamic nuclei 2 h after injections of tetanus toxoid. The intensity of c-fos mRNA expression decreased in the posterior, lateral, and anterior hypothalamic fields 6 h after injections of tetanus toxoid. The maximum number of c-fos mRNA-positive cells in the anterior field and the paraventricular nucleus of the hypothalamic induced by tetanus toxoid, as compared with reactions to administration of physiological saline, were seen at 6 h. Administration of tetanus toxoid and physiological saline did not active the synthesis of c-fos mRNA in the arcuate or supraoptic nuclei at any time point. The number of c-fos mRNA-positive cells returned to baseline by 16 h after tetanus toxoid injections. Thus, this study revealed the temporospatial pattern of activation of hypothalamic structures in response to exposure to an antigen.     

High incidence of horse serum protein allergy in various autoimmune disorders.

In 186 persons (68 patients suffering from different so-called autoimmune diseases, 30 kidney recipients, 38 control patients from a surgical ward, and 50 healthy volunteers) the immune response to horse IgG was examined. The lowest rate of sensitization was found in kidney transplant recipients (3%) and the highest in autoimmune patients (33%). After excluding 39 patient who had received horse serum treatment prior to the examination, it was found that without previous injection of horse serum, 27% of the patients with autoimmune disease were sensitized to horse IgG. Compared to the other groups (kidney transplant recipients, 4%: surgical controls, 0%; healthy volunteers, 3%), this difference was statistically significant (p is less than 0.01).