Effects of hypoxia and tumor necrosis factor-alpha on production of plasminogen activator inhibitor-1 in human proximal renal tubular cells

Chronic hypoxia has been newly proposed as a common mechanism of tubulointerstitial fibrosis in the progression of various chronic inflammatory renal diseases, where PAI-1 plays an important role in the accumulation of extracellular matrix (ECM) through inhibition of plasmin-dependent ECM degradation. In the present study, we investigated the presence of PAI-1 in renal tubular cells by immunostaining renal biopsy samples. We also closely examined the effects of hypoxia and TNF-alpha on PAI-1 expression in cultured human proximal renal tubular cells (HRCs). Confluent cells growth-arrested in DMEM for 24h were exposed to hypoxia (1% O2) and/or TNF-alpha at 10 ng/ml for 24 hours. Amounts of PAI-1 protein and mRNA after stimulation were measured by ELISA and TaqMan quantitative PCR, respectively and compared to those in cells incubated under control conditions (18% O2 without TNF-alpha). HIF-1alpha was demonstrated by immunoblot analysis. In crescentic glomerulonephritis, clusters of proximal tubules were specifically stained for PAI-1. Treatment of 24 hours with hypoxia, TNF-alpha and their combination induced a 2.7-fold, a 1.8-fold, and a 4.6-fold increase in PAI-1 protein secretion, and produced a 3.6-fold, a 3.3-fold, and a 12.1-fold increase at the PAI-1 mRNA level, respectively. Immunoblot analysis revealed that hypoxia-inducible factor-1alpha (HIF-1alpha) was markedly accumulated in the nuclear fraction after 16-hours exposure of HPTECs to hypoxia but not to TNF-alpha. In conclusion, hypoxia induces PAI-1 expression via remarkable nuclear accumulation of HIF-1alpha in HRCs. TNF-alpha can enhance this hypoxia-induced PAI-1 expression.     

Angiogenic endothelium-specific nestin expression is enhanced by the first intron of the nestin gene

Nestin is a member of intermediate filaments abundantly expressed in neural stem cells and glioblastomas. The nestin gene has four exons and three introns, and neural cell-specific expression is regulated by the second intron. We previously reported that nestin was invariably detected in the tumor endothelium in gliomas even though tumor cells were negative for nestin. In the present study, we further confirmed nestin immunostaining in tumor endothelium of a variety of common cancers, including lung, stomach, colon, and cervical carcinomas. We examined an endothelium-specific regulator using human umbilical vein endothelial cells (HUVECs) and human glioblastoma-derived U251 cells. In a luciferase reporter assay, the first intron plus 5' upstream promoter (5'UP) gave the highest activity, followed by 5'UP, and the second intron plus 5'UP. However, the assay values were much lower by HUVEC extracts than by U251 cell extracts. Although green fluorescent protein expression was positive over all U251 cells under either the first intron, second intron, or ubiquitously active CAG promoter, the fluorescence in HUVECs was limited to a few cells even under the first intron. This difference came from the growth feature of HUVECs which exhibit growth arrest by contact inhibition. We found that the nestin expression was specific to proliferative endothelium, by using proliferation markers in hemangioblastomas and in situ hybridization. Using an endothelial tube formation assay, tyrosine kinase domain-deleted VEGF receptor KDR effectively abolished the tube formation under the first intron. We suggest that the nestin expression in tumor endothelium is enhanced by the first intron.     

Dietary aspartame with protein on plasma and brain amino acids, brain monoamines and behavior in rats

Aspartame (APM; L-aspartyl-L-phenylalanine methyl ester), was investigated for its ability to alter levels of the large neutral amino acids and monoamines in overnight fasted rats allowed to consume meals with or without protein for two hours. Additionally, the possible long term behavioral consequences of APM in 25% casein diets with or without 10% sucrose were determined. Acute APM ingestion increased both plasma and brain phenylalanine and tyrosine levels, but brain tryptophan levels were not altered regardless of dietary protein. Brain norepinephrine and dopamine levels were unaltered by any of the diet while serotonin levels were slightly increased when a protein-free diet was consumed. But APM and/or protein ingestion minimized this increase of brain serotonin levels as much as controls. Chronic APM ingestion failed to influence diurnal feeding patterns, meal size distributions, or diurnal patterns of spontaneous motor activity. The chronic ingestion of abuse doses of APM produced no significant chemical changes in brain capable of altering behavioral parameters believed to be controlled by monoamines in rats.     

An autopsy case of acquired immune deficiency syndrome (AIDS) with preceding aplastic anemia

A case of acquired immunodeficiency syndrome (AIDS) with preceding aplastic anemia is reported. The patient was a 36 year old female who had been diagnosed as having aplastic anemia 10 years before and thereafter had received multiple transfusions. Human immunodeficiency virus (HIV)-seropositivity was revealed 10 months prior to her death, but no particular clinical signs indicating HIV infection, pre-AIDS or onset of AIDS were recognized before serological diagnosis, although the slow progression of leukopenia was noted along with thrombocytopenia. Her general condition deteriorated during the last 10 months accompanied by an acute decrease In the CD4/CD8 ratio. Autopsy revealed full-blown AIDS: systemic aspergillosis, progressive multifocal leukoencephalopathy, Epstein-Barr virus-related B cell lymphoma arising in the diaphragm and severe lymphocyte depletion in the lymph nodes and spleen. Markedly hypo-plastic bone marrow was considered to be primarily attributable to the aplastic anemia but the affection of AIDS was not excluded. The possible transmission route of HIV and the effect of the preceding aplastic anemia on the infection and clinical course of AIDS are discussed.     

Radiation-induced reactive oxygen species formation prior to oxidative DNA damage in human peripheral T cells

Previously, we demonstrated that human peripheral T lymphocytes revealed early apoptotic changes (annexin V-positive) and late apoptotic changes (propidium iodide-positive), at 13 and 24 h, respectively, after irradiation of 5 Gy. Changes in mitochondrial membrane potential were observed at 10 h after irradiation of 5 Gy. Subsequently, mitochondrial cytochrome c-release was confirmed. In order to elucidate the mechanism which acts prior to the mitochondrial membrane potential changes, we examined in the previous study the radiation dose and the timing of oxidative DNA damage induced in human peripheral T lymphocytes following 10 MV X-ray irradiation. As a result, the production of 8-oxoguanine, i.e., the product of oxidative DNA damage, was clearly identified starting at 10, 6, and 3 h, after 2, 5, and 20 Gy of irradiation, respectively. Therefore, we examined in the present study reactive oxygen species (ROS) formation in T lymphocytes following 5 Gy of irradiation. Using a CCD camera system, we monitored fluorescence in T lymphocytes loaded with the succinimidyl ester of dichlorodihydrofluorescein diacetate (H2DCFDA), which is non-fluorescent until oxidized by ROS. We found that ROS formation occurred immediately after irradiation, continued for several hours, and resulted in oxidative DNA damage. Therefore, the origin of hyper-radiosensitivity of T lymphocytes seemed to be the high production of ROS in the mitochondrial DNA following irradiation.     

Allergenicity of the osmophilic fungus Aspergillus restrictus evaluated by skin prick test and radioallergosorbent test

Recently large amounts of Aspergillus restrictus, a species of osmophilic fungi, have been detected in house dust using culture media with low water activity. But little attention has been paid to this fungus as an allergen. In the present study, the authors examined the allergenic activity of A. restrictus by skin prick tests and radioallergosorbent tests (RAST) on 94 asthmatic patients (mean age 12.0, range 3-18). Aspergillus fumigatus, Alternaria alternata and house dust were used for comparison. In the skin prick tests, A. restrictus, A. fumigatus, A. alternata and house dust elicited positive reactions in 8 (8.5%), 8 (8.5%), 15 (16.0%) and 69 (73.4%) patients, respectively. RAST showed positive reactions in 27 (28.7%) subjects for A. restrictus, 22 (23.4%) for A. fumigatus, 35 (37.2%) for A. alternata, and 75 (79.8%) for house dust. These results indicated that some asthmatic individuals showed immediate-type hypersensitivity to A. restrictus, and the prevalence of hypersensitivity of A. restrictus determined by skin prick tests and RAST was comparable with that of A. fumigatus but lower than that of A. alternata or house dust. This indicates that this fungal species may be of importance as a causative agent in atopic diseases.     

Claudin‐7 Expressed on Lateral Membrane of Rat Epididymal Epithelium does not Form Aberrant Tight Junction Strands

Claudins are integral membrane proteins at tight junctions (TJs) and form TJ strands. In the present study, we found that claudin‐7 was localized along the entire lateral membranes of epididymal epithelium, including the apical junctional region throughout the epididymis, but claudin‐8 was restricted to the apical junctional region. This finding raises the possibility that aberrant TJ strands may be formed on lateral membranes. Thus, we focused on examining whether TJ strands exist on lateral membranes of epididymal epithelium. Freeze‐fracture electron microscopy showed that aberrant TJ strands were observed in only a few principal cells in all segments of the epididymis except for the initial segment, indicating that the occurrence of aberrant strands is very rare. Aberrant TJ strands were smooth and not subdivided into individual particles in the protoplasmic face, and complementary grooves in the extracellular face were almost free of particles. Aberrant TJ strands in the distal caput and corpus epididymis were accompanied by many vesicle‐like structures but those in the proximal caput and cauda epididymis were not. These results suggest that most of claudin‐7 in lateral membranes may exist in a nonpolymerized form and may play some different roles other than the formation of TJ strands, for example, in the formation of a pool of claudin proteins or in the reinforcement of cell adhesion. Anat Rec, 1431‐1438, 2007. © 2007 Wiley‐Liss, Inc.     

Effects of 12 weeks of aerobic exercise plus dietary restriction on body composition,resting energy expenditure and aerobic fitness in mildly obese middle-aged women

This study investigated the effects of 12 weeks of aerobic exercise plus voluntary food restriction on the body composition, resting metabolic rate (RMR) and aerobic fitness of mildly obese middle-aged women. The subjects were randomly assigned to exercise/diet (n = 17) or control (n = 15) groups. The exercise/diet group participated in an aerobic training programme, 45–60 min · day ^–1 at 50%–60% of maximal oxygen uptake (VO_2max), 3–4 days · week^–1, and also adopted a self-regulated energy deficit relative to predicted energy requirements (–1.05 MJ · day ^–1 to –1.14 MJ · day ^–1 ). After the regimen had been followed for 12 weeks, the body mass of the subjects had decreased by an average of 4.5 kg, due mainly to fat loss, with little change of fat free mass (m _ff). The absolute RMR did not change, but the experimental group showed significant increases in the RMR per unit of body mass (10%) and the RMR per unit of m _ff (4%). The increase in RMR/m _ff was not correlated with any increase in VO_2max/m _ff. The resting heat production per unit of essential body mass increased by an average of 21%, but the resting heat production rate per unit of fat tissue mass remained unchanged. We concluded that aerobic exercise enhances the effect of moderate dietary restriction by augmenting the metabolic activity of lean tissue.