Perinatal exposure to di-(2-ethylhexyl) phthalate induces hepatic lipid accumulation mediated by diacylglycerol acyltransferase 1.

INTRODUCTION: Di-(2-ethylhexyl) phthalate (DEHP) is a commonly used plasticizer in consumer products and medical devices. It is also suspected to exacerbate the development of fatty liver. However, the mechanisms underlying excessive lipid synthesis and its deposition in the liver are yet to be identified. This study was aimed to evaluate the molecular mechanisms of hepatic lipid accumulation in adult male offspring after perinatal exposure to DEHP. METHOD: Corn oil and DEHP (0.75 mg/kg/day) were administered once per day to dam from gestation day 6 to postnatal day (PND) 21 by oral gavage. After the weaning period, DEHP treated male pups were categorized into early life stage- and lifelong period group. Male rats both control and early life stage group administered corn oil, and lifelong period group administered DEHP from PND 22 to 70. Histological examination and triglyceride (TG) levels in the liver were analyzed. Expressions of transcription factors associated with lipid accumulation in the liver were analyzed. RESULTS: Both early life stage- and lifelong period group, hepatic TG levels, and mRNA and protein expression of diacylglycerol acyltransferase 1 (DGAT1) were significantly higher than control (TG: all p < 0.05, mRNA & protein: p < 0.05 and p < 0.001, respectively). The average body weight from PND 35 to 63, and mRNA and protein expression of sterol regulatory element binding protein 1c in lifelong period group were significantly lower than control (all p < 0.05); however, alanine transaminase were significantly higher than control (p < 0.01). CONCLUSION: Perinatal exposure to DEHP may induce the hepatic lipid accumulation through up-regulation of DGAT1 expression.

D-dimer as a predictor of early neurologic deterioration in cryptogenic stroke with active cancer.

BACKGROUND AND PURPOSE: The occurrence of stroke in cancer patients is caused by conventional vascular risk factors and cancer-specific mechanisms. However, cryptogenic stroke in patients with cancer was considered to be more related to cancer-specific hypercoagulability. In this study, we investigated the potential of the D-dimer level to serve as a predictor of early neurologic deterioration (END) in cryptogenic stroke patients with active cancer. METHODS: We recruited 109 cryptogenic stroke patients with active cancer within 72 h of symptom onset. We defined END as an increase of ≥1 point in the motor National Institutes of Health Stroke Scale (NIHSS) score or ≥2 points in the total NIHSS score within 72 h of admission. After adjusting for potential confounding factors in the multivariate analysis, we calculated the odds ratios (ORs) and confidence intervals (CIs) of D-dimer in the prediction of END. RESULTS: Among 109 patients, END events were identified in 34 (31%) patients within 72 h. END was significantly associated with systemic metastasis, multiple vascular territory lesions on the initial magnetic resonance imaging (MRI), initial NIHSS score and D-dimer levels. In the multivariate analysis, the D-dimer level (adjusted OR, 1.11; 95% CI, 1.04-1.17; P < 0.01) and initial NIHSS score (adjusted OR, 1.08; 95% CI, 1.01-1.15; P = 0.03) predicted END after adjusting for potential confounding factors. In the subgroup analysis of 72 follow-up MRIs, D-dimer level was also correlated with new territory lesions on the follow-up MRI in a dose-dependent manner. CONCLUSION: Ischemic stroke patients with active cancer and elevated D-dimer levels appear to be at increased risk for END recurrent thromboembolic stroke.

Tannerella forsythia GroEL induces inflammatory bone resorption and synergizes with interleukin-17.

Tannerella forsythia is a major periodontal pathogen, and T. forsythia GroEL is a molecular chaperone homologous to human heat-shock protein 60. Interleukin-17 (IL-17) has been implicated in the pathogenesis of periodontitis and several systemic diseases. This study investigated the potential of T. forsythia GroEL to induce inflammatory bone resorption and examined the cooperative effect of IL-17 and T. forsythia GroEL on inflammatory responses. Human gingival fibroblasts (HGFs) and periodontal ligament (PDL) fibroblasts were stimulated with T. forsythia GroEL and/or IL-17. Gene expression of IL-6, IL-8, and cyclooxygenase-2 (COX-2) and concentrations of IL-6, IL-8, and prostaglandin E2 (PGE2 ) were measured by real-time reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assays, respectively. After stimulation of MG63 cells with T. forsythia GroEL and/or IL-17, gene expression of osteoprotegerin (OPG) was examined. After subcutaneous injection of T. forsythia GroEL and/or IL-17 above the calvaria of BALB/c mice, calvarial bone resorption was assessed by micro-computed tomography and histological examination. Tannerella forsythia GroEL induced IL-6 and IL-8 production in HGFs and PDL cells, and IL-17 further promoted IL-6 and IL-8 production. Both T. forsythia GroEL and IL-17 synergistically increased PGE2 production and inhibited OPG gene expression. Calvarial bone resorption was induced by T. forsythia GroEL injection, and simultaneous injection of T. forsythia GroEL and IL-17 further increased bone resorption. These results suggest that T. forsythia GroEL is a novel virulence factor that can contribute to inflammatory bone resorption caused by T. forsythia and synergizes with IL-17 to exacerbate inflammation and bone resorption.

Prolonged sleep increases the risk of intracerebral haemorrhage: a nationwide case-control study.

BACKGROUND AND PURPOSE: Although abnormal sleep duration is positively associated with increased risk for cardiovascular disease and mortality, the specific impact on intracerebral haemorrhage (ICH) risk remains unclear. The relationship between sleep duration and the risk of ICH was investigated in our study. METHODS: A nationwide, multicentre matched case-control study was performed to investigate the risk factors for haemorrhagic stroke, using patients from 33 hospitals in Korea. In all, 490 patients with ICH and 980 age- and sex-matched controls were enrolled. Detailed information regarding sleep, sociodemographic factors, lifestyle and medical history before ICH onset was obtained using qualified structured questionnaires. Sleep duration was categorized and the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using a conditional logistic regression with 7 h as the reference duration. RESULTS: The number of subjects with long sleep duration, more than 8 h, was significantly greater in the ICH group than in the control group (≥8 h, 30.4% vs. 22.6%, P = 0.002). After controlling for relevant confounding factors, longer sleep duration was found to be independently associated with the risk of ICH in a dose-response manner (8 h, OR 1.57, 95% CI 1.00-2.47; ≥9 h, OR 5.00, 95% CI 2.18-11.47). CONCLUSIONS: Our study suggested that long sleep duration is positively associated with an increased ICH risk in a dose-dependent manner. Further studies on the relationship linking long sleep duration with increased risk of ICH are required.

Lower Ras expression as an independent predictor of patient outcomes in lung cancer treated with bevacizumab plus chemotherapy.

The objective of this study was to analyze the predictive roles of VEGF/KDR/Ras/MAPK gene expression in patients with advanced non-small-cell lung cancer (NSCLC) treated with bevacizumab plus chemotherapy. Twenty-five patients participating in an open-label phase IV trial (SAiL, MO19390) with available tumor tissues were analyzed. The mRNA expression levels of VEGF, kinase insert domain receptor (KDR), Ras, and mitogen-activated protein kinase (MAPK) in tumor tissues were detected using real-time quantitative PCR methods. The relationships between gene expression and disease control rate (DCR), progression-free survival (PFS), and overall survival (OS) were assessed. Patients with lower Ras expression had a longer PFS and OS than patients with higher expression (median PFS, 9.9 vs 5.5 months, χ(2)=3.944, P=0.047; OS, 19.3 vs 7.1 months, χ(2)=9.384, P=0.002). The PFS and OS of patients with lower and higher MAPK expression exhibited a marginal and significant difference (median PFS, 9.9 vs 5.5 months, χ(2)=3.464, P=0.063; OS, 19.3 vs 9.7 months, χ(2)=5.298, P=0.021), respectively. Multivariate analyses using Cox's proportional hazards model showed that Ras is an independent predictor of OS (χ(2)=9.384, P=0.002). No differences in DCR were found according to Ras expression level. The results indicate that Ras is an independent predictor of OS. Thus, patients with lower Ras expression are most likely to benefit from bevacizumab plus chemotherapy treatment regimen. Patients with higher levels of Ras should receive other inhibitors that target Ras. The results also suggest that gene therapies that decrease RAS expression combined with bevacizumab may improve lung cancer treatment. Although there is a very important implication to patient selection in the target therapy, the data in this study are very preliminary owing to the too small sample size. Therefore, further research involving large numbers of patients and a prospective assessment of low and high RAS mRNA expressions getting the same treatments need to be done before conclusions can be made.

Prognostic significance of cyclinD1 amplification and the co-alteration of cyclinD1/pRb/ppRb in patients with esophageal squamous cell carcinoma.

CyclinD1/pRb/ppRb is one of the most important pathways regulating the cell cycle, and related with the development of many cancers. However, the co-alteration of CyclinD1/pRb/ppRb in esophageal squamous cell carcinomas is less understood. This study aims to analyze the combined prognostic significance of cyclinD1 (CCND1) DNA amplification and the co-alteration of CCND1/pRb/ppRB in patients with esophageal squamous cell carcinoma. CCND1 DNA amplification and the protein expression of CCND1, pRb, and ppRb on 100 tumor specimens and 11 normal tissues were detected using real-time quantitative reverse transcription polymerase chain reaction and immunohistochemistry, respectively. Their prognosis significance was analyzed by Kaplan-Meier method. We found that 41% of the patients had CCND1 DNA amplification, which had a short survival time compared with the patients without CCND1 amplification (25.63 months vs. not reached, P=0.007). The patients with the co-alternation of CCND1(+) /pRb(-) /ppRb(+) protein expression levels have a poorer overall survival than the others (11.4 vs. 43.4 months, P=0.001). Cox regression analysis showed that the co-alternation of CCND1/pRb/ppRb and CyclinD1 amplification were the two most independent prognosis factors of patients with esophageal cancer. These findings suggested that CCND1 amplification and co-alternation of CCND1(+) /pRb(-) /ppRb(+) may play a crucial role in the prognostic evaluation of patients with esophageal cancer, and the patients with CCND1(+) /pRb(-) /ppRb(+) have the worst prognosis in all the patients. The results also indicated that the patients with CCND1 amplification or co-alternation of CyclinD1(+) /pRb(-) /ppRb(+) might be the preponderant people for therapy targeting the CCND1/pRb/ppRb pathway in the future.

A dendritic cell-based tumour vaccine for lung cancer: full-length XAGE-1b protein-pulsed dendritic cells induce specific cytotoxic T lymphocytes in vitro.

XAGE-1b is regarded as one of the most immunogenic antigens and the most promising targets for lung adenocarcinoma immunotherapy. In this study, we sought to determine whether monocyte-derived dendritic cells (DCs) pulsed with purified full-length XAGE-1b could induce specific cytotoxic T lymphocytes (CTLs) against tumour cells from patients with non-small cell lung cancer (NSCLC) in vitro. XAGE-1b mRNA expression was examined in primary cultures of lung cancer cells and normal lung epithelial cells established from fresh tissues surgically resected from 30 patients with NSCLC using reverse transcription-polymerase chain reaction (RT-PCR). XAGE-1b mRNA expression was observed in 11 of 18 (61.1%) adenocarcinomas and one of 12 (8.3%) lung cancers of other histological types (P = 0.015). The 246-base pairs XAGE-1b gene was inserted into a recombinant expression vector. Full-length XAGE-1b was then expressed in BL21 (DE3) Escherichia coli and purified by AKTA-fast performance liquid chromatography (FPLC). DCs generated from peripheral blood mononuclear cells were pulsed with XAGE-1b by incubation with the protein at an immature stage. The XAGE-1b-pulsed DCs induced CTLs following 14 days of co-culture. Finally, an adherent target detachment (ATD) assay was performed to test the cytotoxicity of the XAGE-1b-specific CTLs against cancer cells and normal lung epithelial cells. The XAGE-1b-specific CTLs had a stronger lytic effect on autologous XAGE-1b mRNA-positive cancer cells than on autologous XAGE-1b mRNA-negative cancer cells or allogenous XAGE-1b mRNA-positive cancer cells. The CTLs had no lytic activity against normal lung epithelial cells. These results can be used to develop simple and effective cancer/testis antigen-based immunotherapies for NSCLC.

Age-related change of somatostatin-immunoreactive neurones in the main olfactory bulb of the rat.

Somatostatin is found in the olfactory system, including the main olfactory bulb (MOB), and is thought to be one of the neuroactive substances for olfaction. However, somatostatin immunoreactivity in the olfactory system has not been determined during ageing. Hence, we examined the age-related changes of somatostatin-immunoreactive (IR) neurones in the rat MOB over a period of 2 years, at the following various ageing stages: post-natal month 1 (PM 1), PM 3, PM 6, PM 12 and PM 24. In PM 1 group, a few somatostatin-IR neurones were detected in the granule cell layer (GCL), and had slender or oval somata and short processes. At PM 3, somatostatin-IR neurones were observed in the glomerular, external plexiform and GCL. The size of somatostatin-IR somata was larger than that at PM 1. In PM 6 group, the number and size of somatostatin-IR neurones increased, and their processes became longer while running in various directions. At PM 12, somatostatin-IR neurones increased in number, and their processes became markedly longer than those at PM 6. At this stage, somatostatin-IR neurones had multipolar somata, and were the largest in size. In PM 24 group, somatostatin-IR neurones were most numerous. However, the processes of somatostatin-IR neurones were shorter than those at PM 12. This study suggests that the increased number of somatostatin-IR neurones in the MOB of aged rats may play a role to compensate for any decrease of olfactory function.

Inhibition of TNF-alpha, IL-1beta, and IL-6 productions and NF-kappa B activation in lipopolysaccharide-activated RAW 264.7 macrophages by catalposide, an iridoid glycoside isolated from Catalpa ovata G. Don (Bignoniaceae).

Catalposide, the major iridoid glycoside isolated from the stem bark of Catalpa ovata G. Don (Bignoniaceae), was found to inhibit the productions of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and interleukin-6 (IL-6), and the activation of nuclear factor kappaB (NF-kappaB) in RAW 264.7 macrophages activated with lipopolysaccharide (LPS). Catalposide also inhibited the expressions of TNF-alpha, IL-1beta, and IL-6 genes and the nuclear translocation of p65 subunit of NF-kappaB in LPS-activated RAW 264.7 cells. Flow cytometric analysis revealed that catalposide suppressed the binding of FITC-conjugated LPS to CD14 on the surface of cells, probably resulting in the inhibitory effects on TNF-alpha, IL-1beta, and IL-6 productions and NF-kappaB activation. These findings suggest that catalposide could be an attractive candidate for adjunctive therapy in gram-negative bacterial infections.

The alteration of corticotropin-releasing factor (CRF) receptor immunoreactivity in the gerbil hippocampus and neocortex following ischemic insults.

Recently, we suggested that the ectopic expression of corticotropin-releasing factor (CRF) is associated with processes linked to neuronal injury and/or degeneration in response to an ischemic insult. However, little experimental data currently links the CRF receptor directly to neuronal death induced by ischemia. Therefore, in the present study, we investigated the temporal and spatial changes in CRF receptor immunoreactivity in the hippocampus and the neocortex after transient ischemia. CRF receptor immunoreactivity in the hippocampus was reduced up to 24h after ischemia insult, as compared to the sham. Interestingly, CRF receptor immunoreactivity disappeared in the CA1 region of the hippocampus at 4 days in the post-ischemic group. The other regions of hippocampus maintained their immunoreactivities at this time point. On the other hand, in the neocortex, 3h after transient ischemia, the CRF receptor immunoreactivity was elevated in regions vulnerable to ischemia. At 12h post-ischemia, its immunoreactivity had decreased versus the sham operated animals. These results suggest that the selectively ectopic expression of CRF following ischemia, which we reported previously, may regulate inflammatory responses. In addition, these findings also suggest that the mechanisms of neuronal death as mediated by CRF receptor differ in the hippocampus and the neocortex.

CaR-mediated COX-2 expression in primary cultured mTAL cells.

Primary cultures of medullary thick ascending limb (mTAL) cells retain the capacity to express calcium-sensing receptor (CaR) mRNA and protein. Increases in cyclooxygenase-2 (COX-2) mRNA accumulation, protein expression, and PGE(2) synthesis were observed in a dose- and time-dependent manner after exposure of these cells to extracellular calcium (Ca(o)(2+)). Moreover, transfection of mTAL cells with a CaR overexpression vector significantly enhanced COX-2 expression and PGE(2) production in response to calcium compared with cells transfected with an empty vector. Challenge with the CaR-selective agonist poly-L-arginine (PLA) also increased COX-2 mRNA accumulation, protein expression, and PGE(2) synthesis. Furthermore, Ca(o)(2+)- and PLA-mediated PGE(2) production was abolished in the presence of NS-398 or nimesulide, two different COX-2-selective inhibitors. These data suggest that intracellular signaling mechanisms initiated via activation of CaR contribute to COX-2-dependent PGE(2) synthesis in the mTAL. Because Ca(o)(2+) concentration varies along Henle's loop, calcium may contribute to salt and water balance via a COX-2- and CaR-dependent mechanism. Thus novel calcimimetics might be useful in conditions such as hypertension in which manipulation of extracellular fluid volume provides beneficial effects.

Cholesterol-dependent interaction of syncollin with the membrane of the pancreatic zymogen granule.

Syncollin is a protein of the pancreatic zymogen granule that was isolated through its ability to bind to syntaxin. Despite this in vitro interaction, it is now clear that syncollin is present on the luminal side of the zymogen granule membrane. Here we show that there are two pools of syncollin within the zymogen granule: one free in the lumen and the other tightly associated with the granule membrane. When unheated or cross-linked samples of membrane-derived syncollin are analysed by SDS/PAGE, higher-order forms are seen in addition to the monomer, which has an apparent molecular mass of 16 kDa. Extraction of cholesterol from the granule membrane by treatment with methyl-beta-cyclodextrin causes the detachment of syncollin, and this effect is enhanced at a high salt concentration. Purified syncollin is able to bind to brain liposomes at pH 5.0, but not at pH 11.0, a condition that also causes its extraction from granule membranes. Syncollin binds only poorly to dioleoyl phosphatidylcholine liposomes, but binding is dramatically enhanced by the inclusion of cholesterol. Finally, cholesterol can be co-immunoprecipitated with syncollin. We conclude that syncollin is able to interact directly with membrane lipids, and to insert into the granule membrane in a cholesterol-dependent manner. Membrane-associated syncollin apparently exists as a homo-oligomer, possibly consisting of six subunits, and its association with the membrane may be stabilized by electrostatic interactions with either other proteins or phospholipids.

Chronological changes of N-methyl-D-aspartate receptors and excitatory amino acid carrier 1 immunoreactivities in CA1 area and subiculum after transient forebrain ischemia.

We investigated changes of immunoreactivities of N-methyl-D-aspartate receptor (NR) and of excitatory amino acid carrier 1 (EAAC-1), the neuronal glutamate transporter, in the vulnerable CA1 area and the less vulnerable subiculum of the gerbil hippocampus at various times following transient forebrain ischemia. At 30 min after ischemia-reperfusion, the intensity of NR immunoreactivity increased markedly in neurons of CA1 and subiculum, particularly NR2A/B, while EAAC-1 immunoreactivity was reduced in CA1. At 3 hr after reperfusion, the density of NR1 immunoreactivity markedly decreased in CA1. In contrast EAAC-1 immunoreactivity increased in CA1 and in the subiculum. At 12 hr after reperfusion, the decrease of NR1 immunoreactivity was not detected whereas EAAC-1 immunoreactivities in the CA1 area were intensified. In the subiculum, both NR subunits immunoreactivities decreased significantly, in contrast to the maintenance of EAAC-1 immunoreactivity. At 24 hr after reperfusion, both NR2A/B and EAAC-1 immunoreactivities decreased markedly in CA1 and subiculum. We tentatively suggest that the increase of NR immunoreactivity in CA1 at early times after ischemia-reperfusion may increase the delayed neuronal death, and that the increase or maintenance of EAAC-1 immunoreactivity at early times after ischemia-reperfusion may be an important factor in survival of neurons.

Age-related change of neuropeptide Y-immunoreactive neurons in the rat anterior olfactory nucleus.

Neuropeptide Y (NPY) is located in the olfactory system, including the olfactory bulb, and is thought to be one of the main neurotransmitters for olfaction. Thus, we examined age-related changes of NPY-immunoreactive (IR) neurons in the rat anterior olfactory nucleus (AON) at various aging stages over a period of 2 years; postnatal months 1 (PM 1), PM 6, PM 12 and PM 24. NPY-IR neurons in the AON were present in the lateral and medial subdivisions at PM 1 and at PM 6 were distributed in all subdivisions of the AON. Prior to PM 12, the NPY-IR neurons showed a tendency to change from bipolar cells with short processes into multipolar cells with long processes. Moreover, the population of NPY-IR neurons and nerve fibers in the AON increased in proportion to age. In particular, the number of NPY-IR neurons increased about 6-fold between PM 1 and PM 3. At PM 24, the number of NPY-IR neurons was much smaller than that at PM 12 and somal size had decreased. It is therefore suggested that the dramatic increase in the number and size of the NPY-IR neurons between PM 1 and PM 3 may be associated with sexual maturation and that the decrease in the number and cell size of the NPY-IR neurons at PM 24 may underlie age-related changes in the olfactory process.

Analysis of the association of syncollin with the membrane of the pancreatic zymogen granule.

Syncollin is a pancreatic zymogen granule protein that was isolated through its ability to bind to syntaxin. Here we show that syncollin has a cleavable signal sequence and can be removed from granule membranes by washing with sodium carbonate. When membranes were subjected to Triton X-114 partitioning, syncollin was found predominantly in the aqueous phase, indicating that it is not sufficiently hydrophobic to be embedded in the membrane. Syncollin has intramolecular disulfide bonds and was accessible to water-soluble cross-linking and biotinylating reagents only when granules were lysed by sonication. These results indicate that syncollin is tightly bound to the luminal surface of the granule membrane. In situ, syncollin was resistant to proteases such as trypsin. When granule membranes were solubilized in ionic detergents such as deoxycholate, this trypsin resistance was maintained, and syncollin migrated on sucrose density gradients as a large (150 kDa) protein. In contrast, in non-ionic detergents such as Triton X-100, syncollin became partially sensitive to trypsin and behaved as a monomer. Syncollin in alkaline extracts of granule membranes was also monomeric. However, reduction of the pH regenerated the oligomeric form, which was insoluble. We conclude that syncollin exists as a homo-oligomer and that its ability to self-associate can be reversibly modulated via changes in pH. In light of our findings, we reassess the likely role of syncollin in the pancreatic acinar cell.

Cyclooxygenase-2 expression and function in the medullary thick ascending limb.

The medullary thick ascending limb (MTAL) metabolizes arachidonic acid (AA) via cytochrome P-450 (CyP450)- and cyclooxygenase (COX)-dependent pathways. In the present study, we demonstrated that the COX-2-selective inhibitor, NS-398, prevented tumor necrosis factor-alpha (TNF)- and phorbol myristate acetate (PMA)-mediated increases in PGE(2) production by cultured MTAL cells. Accumulation of COX-2, but not COX-1, mRNA increased when cells were challenged with TNF (1 nM) or PMA (1 microM). Pretreatment of cells for 30 min with actinomycin D (AcD, 1 microM) had little effect on COX-2 mRNA accumulation in unstimulated cells or in cells challenged with either TNF or PMA. Moreover, a posttranscriptional mechanism(s) appears to contribute significantly to COX-2 mRNA accumulation as pretreatment for 15 min with cycloheximide (CHX, 1 microM) caused a superinduction of COX-2 mRNA accumulation in unstimulated cells as well as in cells challenged with either TNF or PMA. Expression of COX-2 protein in unstimulated MTAL cells was attenuated by preincubation for 2 h with dexamethasone (Dex, 2 microM); however, Dex had little or no effect on COX-2 expression in cells challenged with either PMA or TNF. The time-dependent inhibition of 86Rb uptake by MTAL cells challenged with TNF was diminished by pretreating cells with NS-398. These data suggest that TNF-mediated induction of COX-2 protein expression accounted for the lag-time required for this cytokine to inhibit 86Rb uptake in MTAL cells.

Angiotensin II induces TNF production by the thick ascending limb: functional implications.

The effects of angiotensin II (ANG II) on tumor necrosis factor-alpha (TNF) production were determined in freshly isolated tubules from the medullary thick ascending limb (MTAL). ANG II (10(-9) M) increased the accumulation of TNF mRNA associated with enhanced production of TNF by approximately five- to sixfold. ANG II also increased prostaglandin E2 (PGE2) production by the MTAL in a dose-dependent manner and exerted biphasic differential effects on 86Rb uptake, depending on the exposure time of the tubules to the peptide and the doses used. Low-dose ANG II (10(-11) M) increased 86Rb uptake by MTAL tubules after a "short-term" (15 min) challenge, whereas uptake was inhibited after a "long-term" (3 h) incubation period. High-dose ANG II (10(-6) M) inhibited MTAL 86Rb uptake, irrespective of incubation time. Uptake of 86Rb was inhibited by approximately 60% in MTAL tubules that were challenged for 3 h with ANG II. The inhibitory action of ANG II was prevented by eliminating the participation of either TNF with antisera to the cytokine or PGE2 by inhibition of cyclooxygenase with indomethacin. We conclude that ANG II regulates TNF production in the MTAL, an interaction that affects 86Rb uptake via an eicosanoid-dependent mechanism in this nephron segment.

Endothelin-1 secretion by human fibroblasts in culture: effects of cell density and IFN-beta.

Evidence is presented of ET-1 release by cultured human fibroblasts. Such a conclusion is supported by the parallelism in displacement curves obtained using dilutions of extracts prepared from fibroblast conditioned media and the synthetic ET-1 standards, and the significant time dependent increase in ET-1 content in media from IFN-beta treated human fibroblasts. An increase in cell density significantly elevated the total amount of ET-1 in the conditioned media, although a linear relationship between these two variables was not observed.

Absence of the 40-kDa form of (2'-5')oligoadenylate synthetase and its corresponding mRNA from skin fibroblasts derived from Alzheimer disease patients.

Cultured skin fibroblasts derived from Alzheimer disease patients fail to express the 1.6-kilobase (kb) mRNA and the corresponding 40-kDa form of (2'-5')oligoadenylate (2-5A) synthetase when exposed to interferon. In addition, the 3.6-kb mRNA, which is present in normal fibroblasts, is barely detectable in the Alzheimer disease counterpart. The deficiency of the 2-5A synthetase 1.6-kb mRNA and its corresponding protein is not related to an impairment of interferon receptors but most probably represents an alteration in the expression of the 2-5A synthetase gene. The data have potential implications for the diagnosis of Alzheimer disease and demonstrate that the absence of a specific form of 2-5A synthetase is linked to a disease state.