bluuebunny/crossref_metadata_2025 huggingface dataset:
The use of prophylactic fluconazole in immunocompetent high-risk surgical patients: a meta-analysis
Authors: Ho Kwok M , Lipman Jeffrey , Dobb Geoffrey J , Webb Steven AR
Published: October 2005

Introduction

High-risk surgical patients are at increased risk of fungal infections and candidaemia. Evidence from observational and small randomised controlled studies suggests that prophylactic fluconazole may be effective in reducing fungal infection and mortality. We evaluated the effects of prophylactic fluconazole on the incidence of candidaemia and hospital mortality in immunocompetent high-risk surgical patients.

Methods

Randomised controlled studies involving the use of fluconazole in immunocompetent high-risk surgical patients from the Cochrane Controlled Trial Register (2005, issue 1) and from the EMBASE and MEDLINE databases (1966–30 April 2005), without any language restriction, were included. Two reviewers reviewed the quality of the studies and performed data extraction independently.

Results

Seven randomised controlled studies with a total of 814 immunocompetent high-risk surgical patients were considered. The use of prophylactic fluconazole was associated with a reduction in the proportion of patients with candidaemia (relative risk [RR] = 0.21, 95% confidence interval [CI] = 0.06–0.72, P = 0.01; I2 = 0%) and fungal infections other than lower urinary tract infection (RR = 0.39, 95% CI = 0.24–0.65, P = 0.0003; I2 = 0%), but was associated with only a trend towards a reduction in hospital mortality (RR = 0.82, 95% CI = 0.62–1.08, P = 0.15; I2 = 7%). The proportion of patients requiring systemic amphotericin B as a rescue therapy for systemic fungal infection was lower after prophylactic use of fluconazole (RR = 0.35, 95% CI = 0.17–0.72, P = 0.004; I2 = 0%). The proportion of patients colonised with or infected with fluconazole-resistant fungi was not significantly different between the fluconazole group and the placebo group (RR = 0.66, 95% CI = 0.22–1.96, P = 0.46; I2 = 0%).

Conclusion

The use of prophylactic fluconazole in immunocompetent high-risk surgical patients is associated with a reduced incidence of candidaemia but with only a trend towards a reduction in hospital mortality.
The interferon-inducible gene, Ifi204, is transcriptionally activated in response to M-CSF, and its expression favors macrophage differentiation in myeloid progenitor cells
Authors: Dauffy Jérémy , Mouchiroud Guy , Bourette Roland P
Published: October 2005

The interferon-inducible (Ifi)204 gene was isolated as a macrophage-colony stimulating factor (M-CSF)-responsive gene using a gene trap approach in the myeloid interleukin-3 (IL-3)-dependent FD-Fms cell line, which differentiates in macrophages in response to M-CSF. Here, we show that Ifi204 was transcriptionally activated in response to M-CSF, and FD-Fms cells decreased their growth and committed toward a macrophage morphology; this induction was abrogated when the differentiation signal of the M-CSF receptor was blocked; the Ifi204 gene was also induced during macrophage differentiation controlled by leukemia inhibitory factor; and the Ifi204 gene is expressed in different mature monocyte/macrophage cells. Finally, we showed that enforced expression of Ifi24 strongly decreased IL-3- and M-CSF-dependent proliferation and conversely, favored macrophage differentiation of FD-Fms cells in response to M-CSF. Altogether, these results demonstrate that the Ifi204 gene is activated during macrophage development and suggest that the Ifi204 protein may act as a regulator of the balance between proliferation and differentiation. Moreover, this study suggests that other members of the Ifi family might act as regulators of hematopoiesis under the control of hemopoietic cytokines.
PAF-receptor antagonists, lovastatin, and the PTK inhibitor genistein inhibit H2O2 secretion by macrophages cultured on oxidized-LDL matrices
Authors: Sethy-Coraci Indra , Crock Lara W , Silverstein Samuel C
Published: October 2005

Adhesion of mononuclear phagocytes (Macs) to extracellular matrices containing oxidized low-density lipoproteins (oxLDL) stimulates these cells to secrete reactive oxygen species (e.g., O2–, H2O2) that are believed to promote atherogenesis. Current in vitro systems designed to measure Mac H2O2 secretion in response to oxLDL show that these cells secrete H2O2 for only a few hours after plating. The slow onset and chronicity of atherogenesis, however, suggested to us that Mac ROS secretion might be sustained for much longer periods when Macs are maintained in an environment resembling that in the intima of arteries undergoing atherogenesis. The findings reported here confirm this suggestion. They show that Macs maintained on collagen IV matrices containing oxLDL in medium containing human plasma-derived serum secrete H2O2 continuously and in large amounts for at least 11 days. Using this system we tested the effects of compounds known to attenuate atherogenesis in vivo. Platelet-activating factor (PAF) receptor antagonists, lovastatin, and the isoflavone protein tyrosine kinase (PTK) inhibitor genistein each reduced H2O2 secretion by Macs maintained on oxLDL-containing matrices by ∼60%. Lovastatin's inhibitory effect was blocked completely by addition of geranylgeranyl pyrophosphate to the medium. We conclude that matrix-bound and oxidized lipoproteins stimulate Macs to produce H2O2 continuously and in large quantities via a pathway that involves PAF receptors and PTK and is reversibly blocked by inhibitors of protein prenylation.
Modulation of phenotype and function of dendritic cells by a therapeutic synthetic killer peptide
Authors: Cenci Elio , Pericolini Eva , Mencacci Antonella , Conti Stefania , Magliani Walter , Bistoni Francesco , Polonelli Luciano , Vecchiarelli Anna
Published: October 2005

The strong microbicidal effects of an engineered synthetic killer peptide (KP), which functionally mimics a fungal killer toxin, have been demonstrated extensively. β-glucan has been identified as a receptor for KP on fungal cell walls. Although the direct microbicidal and related therapeutic effects have been studied in depth, no information currently exists about the interaction of KP with immune cells. In this study, we exploited the possibility of KP binding to different murine immune cell populations. The results demonstrate that KP binds selectively to dendritic cells (DC) and to a lesser extent, to macrophages but not to lymphocytes and neutrophils; KP binding possibly occurs through major histocompatibility complex (MHC) class II, CD16/32, and cellular molecules recognized by anti-specific intercellular adhesion molecule-grabbing nonintegrin R1 antibodies; and KP modulates the expression of costimulatory and MHC molecules on DC and improves their capacity to induce lymphocyte proliferation. These findings provide evidence that this synthetic KP interacts selectively with DC and modulating their multiple functions, might also serve to improve the immune antimicrobial response.
Endotoxin tolerance induces selective alterations in neutrophil function
Authors: Parker Lisa C , Jones Elizabeth C , Prince Lynne R , Dower Steven K , Whyte Moira K B , Sabroe Ian
Published: October 2005

Endotoxin tolerance has the potential to limit phagocyte responses to Toll-like receptor (TLR) agonists, but the role of tolerance in regulating neutrophil responses is unknown. We investigated neutrophil responses to prolonged lipopolysaccharide (LPS) exposure and observed induction of tolerance in intracellular signaling pathways and respiratory burst. These effects were not prevented by granulocyte macrophage-colony stimulating factor (GM-CSF) pretreatment, and tolerized neutrophils retained the ability to respond to GM-CSF and other survival factors with a delay in apoptosis. In addition, LPS-exposed neutrophils showed continued generation of CXC chemokine ligand 8, which was not reduced in tolerized cells. Induction of tolerance was associated with a loss of TLR4 surface expression. Tolerance, therefore, induces a selective reprogramming of neutrophil function, but cells retain a predominantly proinflammatory phenotype.
Synergistic enhancement of cytokine-induced human monocyte matrix metalloproteinase-1 by C-reactive protein and oxidized LDL through differential regulation of monocyte chemotactic protein-1 and prostaglandin E2
Authors: Zhang Yahong , Wahl Larry M
Published: October 2005

C-reactive protein (CRP) and oxidized LDL (ox-LDL) are associated with inflammatory lesions, such as coronary artery disease, in which monocytes and matrix metalloproteinases (MMPs) may play a major role in the rupture of atherosclerotic plaques. Monocytes are recruited to inflammation sites by monocyte chemoattractant protein-1 (MCP-1), which may also participate in the activation of monocytes. The objective of this study was to compare the individual and combined effect of CRP and ox-LDL on human monocyte MMP-1 and the role of MCP-1 in this effect. Although CRP or ox-LDL failed to induce MMP-1 in control monocytes, these molecules enhanced MMP-1 production induced by tumor necrosis factor α (TNF-α) and granulocyte macrophage-colony stimulating factor (GM-CSF) with a synergistic increase in MMP-1 occurring in the presence of both mediators. Enhancement of MMP-1 by CRP and ox-LDL wasattributable to a differential increase in MCP-1 and prostaglandin E2(PGE2). CRP, at physiological concentrations, induced high levels of MCP-1 and relatively low levels of PGE2, whereas ox-LDL caused a significant enhancement of PGE2 with little affect on MCP-1. Accordingly, CRP- and ox-LDL-induced MMP-1 production by monocytes was inhibited by anti-MCP-1 antibodies and indomethacin, respectively. Moreover, addition of exogenous MCP-1 or PGE2 enhanced MMP-1 production by TNF-α- and GM-CSF-stimulated monocytes. These results show that the combination of CRP and ox-LDL can cause a synergistic enhancement of the role of monocytes in inflammation, first, by increasing MCP-1, which attracts more monocytes and directly enhances MMP-1 production by activated monocytes, and second, by elevating PGE2 production, which also leads to higher levels of MMP-1.
Latent TGF-β1-transduced CD4+ T cells suppress the progression of allergic encephalomyelitis
Authors: Murano Mitsuyuki , Xiong Xiaozhong , Murano Naoko , Salzer James L , Lafaille Juan J , Tsiagbe Vincent K
Published: October 2005

Systemic injection of small amounts of transforming growth factor-β (TGF-β), a cytokine produced by lymphoid and other cells, has a profound effect in protecting mice from the nflammatory demyelinating lesions of experimental allergic encephalomyelitis (EAE; an animal model for multiple sclerosis). However, TGF-β has side-effects, which might be avoided if the cells producing TGF-β can be delivered to the affected site in the nervous system to insure its local release in small amounts. Myelin basic protein (MBP)-specific, cloned CD4+ T cells were engineered by retroviral transduction to produce latent TGF-β. Studies about the spontaneous form of EAE in T cell receptor (TCR)-transgenic recombination-activating gene (RAG)-1−/− mice showed that essentially all of the MBP-specific, TCR-transgenic RAG-1−/− (BALB/c×B10.PL)F1 mice develop spontaneous EAE by the age of 11 weeks. By 12 weeks, 25–50% of the mice have died from disease. A single injection of TGF-β1-transduced T helper cell type 1 (Th1) cells significantly protected the mice from EAE, and untransduced Th1 cells did not protect. MBP-specific BALB/c Th2 clones, transduced with TGF-β1-internal ribosome entry site-green fluorescent protein (GFP) significantly reduced EAE induction by untransduced Th1 cells in RAG-1−/− B10.PL mice. Furthermore, the GFP+ TGF-β1-producing Th2 cells were detectable in the spinal cords of the injected mice.
Induction of intracellular calcium elevation by Δ9-tetrahydrocannabinol in T cells involves TRPC1 channels
Authors: Rao Gautham K , Kaminski Norbert E
Published: October 2005

We have reported previously that Δ9-tetrahydrocannabinol (Δ9-THC) treatment of resting human and murine splenic T cells robustly elevated intracellular calcium ([Ca2+]i). The objective of the present investigation was to examine the putative role of [Ca2+]i store depletion and store-operated calcium (SOC) [1] and receptor-operated cation (ROC) channels in the mechanism by which Δ9-THC increases [Ca2+]i in the cannabinoid-2 receptor-expressing human peripheral blood-acute lymphoid leukemia (HPB-ALL) human T cell line. By using the smooth endoplasmic reiculum Ca2+-ATPase pump inhibitor, thapsigargin, and the ryanodine receptor antagonist, 8-bromo-cyclic adenosine diphosphate ribose, we demonstrate that the Δ9-THC-mediated elevation in [Ca2+]i occurs independently of [Ca2+]i store depletion. Furthermore, the ROC channel inhibitor, SK&F 96365 was more efficacious at attenuating the Δ9-THC-mediated elevation in [Ca2+]i than SOC channel inhibitors, 2-aminoethoxydiphenyl borate and La3+. Recently, several members of the transient receptor potential canonical (TRPC) channel subfamily have been suggested to operate as SOC or ROC channels. In the present studies, treatment of HPB-ALL cells with 1-oleoyl-2-acetyl-sn-glycerol (OAG), a cell-permeant analog of diacylglycerol (DAG), which gates several members of the TRPC channel subfamily, rapidly elevated [Ca2+]i, as well as prevented a subsequent, additive elevation in [Ca2+]i by Δ9-THC, independent of protein kinase C. Reverse transcriptase-polymerase chain reaction analysis for TRPC1–7 showed that HPB-ALL cells express detectable mRNA levels of only TRPC1. Finally, small interference RNA knockdown of TRPC1 attenuated the Δ9-THC-mediated elevation of [Ca2+]i. Collectively, these results suggest that Δ9-THC-induced elevation in [Ca2+]i is attributable entirely to extracellular calcium influx, which is independent of [Ca2+]i store depletion, and is mediated, at least partially, through the DAG-sensitive TRPC1 channels.
Common methodology is inadequate for studies on the microbicidal activity of neutrophils
Authors: Decleva Eva , Menegazzi Renzo , Busetto Sara , Patriarca Pierluigi , Dri Pietro
Published: October 2005

Microbicidal activity of neutrophils is usually measured by colony-counting techniques after cell lysis in distilled water. While studying the effect of the reduced nicotinamide adenine dinucleotide phosphate-oxidase inhibitor diphenyleneiodonium (DPI) on the staphylocidal activity of neutrophils, we obtained inconsistent results: various degrees of inhibition in some experiments and no effect in others. The lysis step, i.e., dilution of neutrophils in distilled water, was the source of error. Cell-associated microorganisms were not dispersed effectively by this tretment. We overcame this problem by using water at pH 11 for cell lysis. Under these conditions, killing was inhibited completely and reproducibly by DPI. Here, we show that cell lysis in distilled water is incomplete and leads to an overestimate of microbial killing. This hinders identification of partial defects and makes complete defects appear as partial. We found that DPI-treated neutrophils and chronic granulomatous disease neutrophils were completely defective in killing of Staphylococcus aureus and Candida albicans and partially defective in killing of Escherichia coli after lysis with water pH 11, whereas after lysis in distilled water, killing of S. aureus and C. albicans was ∼60% and ∼70% of control killing, respectively, and killing of E. coli was normal. Likewise, killing of S. aureus by myeloperoxidase-deficient neutrophils was severely impaired after lysis in water pH 11 but appeared normal after lysis in distilled water. As most studies about neutrophil microbicidal activity have been performed using distilled water, our findings indicate that previous data about killing defects and the effects of agents that modulate microbicidal activity of neutrophils should be re-evaluated.
Abnormal regulation of the cytoskeletal regulator Rho typifies macrophages of the major murine models of spontaneous autoimmunity
Authors: Fan Hanli , Patel Vimal A , Longacre Angelika , Levine Jerrold S
Published: October 2005

Macrophages (mφ) from prediseased mice of all the major murine models of spontaneous autoimmunity have an identical defect in cytokine expression that is triggered by serum and/or apoptotic cells. We show here that mφ from prediseased mice of the same models of spontaneous autoimmunity share a serum-dependent defect in the activity of Rho, a cytoplasmic G protein and cytoskeletal regulator. Affected strains include those developing lupus (BXSB, LG, MRL/l+, MRL/lpr, NZBWF1) and autoimmune diabetes (nonobese diabetic). No similar defect in Rho activity occurred in seven control strains. In the presence of serum, Rho activity in mφ from all autoimmune-prone strains was reduced to less than 10% of that in control mice. In contrast, under serum-free conditions, Rho activity was ompletely normal in autoimmune-prone mφ. The activities of Ras, another cytoplasmic G protein, and Rac and Cdc42, two additional G protein regulators of the cytoskeleton, were regulated normally in autoimmune-prone strains. Serum-dependent dysregulation of Rho was associated with multiple abnormalities, including increased adhesion to various surfaces, a more spread dendritic morphology, and an altered actin cytoskeletal organization. Our results suggest that mφ from multiple, genetically diverse, autoimmune-prone strains share a mutation or allelic difference affecting signal transduction within a specific Rho-regulatory pathway.
Ceramide catabolism critically controls survival of human dendritic cells
Authors: Franchi Luigi , Malisan Florence , Tomassini Barbara , Testi Roberto
Published: October 2005

The regulation of dendritic cell (DC) survival is crucial for the modulation of adaptive immunity. Ceramide is a lipid mediator of the stress response, which accumulates intracellularly during DC differentiation. We found that ceramide levels are tightly regulated in human DCs and that the pharmacological inhibition of enzymes responsible for ceramide catabolism, such as ceramidases and sphingosine kinases, sensitizes DCs to ceramide-induced cell death. It is important that inhibition of sphingosine kinases, during lipopolysaccharide stimulation, causes extensive ceramide accumulation and death of DCs. These data indicate that ceramide catabolism regulates urvival of human DCs and reveal novel potential targets for the pharmacological manipulation of the immune response.
Neoadjuvant Chemotherapy With High-Dose Ifosfamide, High-Dose Methotrexate, Cisplatin, and Doxorubicin for Patients With Localized Osteosarcoma of the Extremity: A Joint Study by the Italian and Scandinavian Sarcoma Groups
Authors: Ferrari Stefano , Smeland Sigbjorn , Mercuri Mario , Bertoni Franco , Longhi Alessandra , Ruggieri Pietro , Alvegard Thor A. , Picci Piero , Capanna Rodolfo , Bernini Gabriella , Müller Cristoph , Tienghi Amelia , Wiebe Thomas , Comandone Alessandro , Böhling Tom , Del Prever Adalberto Brach , Brosjö Otte , Bacci Gaetano , Sæter Gunnar
Published: October 2005

Purpose

To explore the effect of high-dose ifosfamide in first-line treatment for patients ≤ 40 years of age with nonmetastatic osteosarcoma of the extremity.

Patients and Methods

From March 1997 to September 2000, 182 patients were evaluated. Primary treatment consisted of two blocks of high-dose ifosfamide (15 g/m2), methotrexate (12 g/m2), cisplatin (120 mg/m2), and doxorubicin (75 mg/m2). Postoperatively, patients received two cycles of doxorubicin (90 mg/m2), and three cycles each of high-dose ifosfamide, methotrexate, and cisplatin (120 to 150 mg/m2). Granulocyte colony-stimulating factor support was mandatory after the high-dose ifosfamide/cisplatin/doxorubicin combination.

Results

No disease progression was recorded during primary chemotherapy, 164 patients (92%) underwent limb-salvage surgery, four patients (2%) underwent rotation plasty, and 11 patients (6%) had limbs amputated. Three (1.6%) patients died as a result of treatment-related toxicity, and one died as a result of pulmonary embolism after pathologic fracture. Grade 4 neutropenia and thrombocytopenia followed 52% and 31% of all courses, respectively, and mild to severe nephrotoxicity was recorded in 19 patients (10%). The median received dose-intensity compared with protocol was 0.82. With a median follow-up of 55 months, the 5-year probability of event-free survival was 64% (95% CI, 57% to 71%) and overall survival was 77% (95% CI, 67% to 81%), whereas seven patients (4%) experienced local recurrence.

Conclusion

The addition of high-dose ifosfamide to methotrexate, cisplatin, and doxorubicin in the preoperative phase is feasible, but with major renal and hematologic toxicities, and survival rates similar to those obtained with four-drug regimens using standard-dose ifosfamide. Italian Sarcoma Group/Scandinavian Sarcoma Group study I showed that in a multicenter setting, more than 90% of patients with osteosarcoma of the extremity can undergo conservative surgery.
Multicenter Phase I/II Study of Cetuximab With Paclitaxel and Carboplatin in Untreated Patients With Stage IV Non–Small-Cell Lung Cancer
Authors: Thienelt Christiane D. , Bunn Paul A. , Hanna Nasser , Rosenberg Arthur , Needle Michael N. , Long Michael E. , Gustafson Daniel L. , Kelly Karen
Published: October 2005

Purpose

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors have demonstrated antitumor activity in patients with non–small-cell lung cancer (NSCLC). This study examined the safety profile of the monoclonal antibody EGFR inhibitor, cetuximab, when added to paclitaxel and carboplatin in untreated patients with stage IV NSCLC. Secondary objectives included efficacy and paclitaxel and carboplatin pharmacokinetics during cetuximab treatment.

Patients and Methods

Patients with tumor evidence of EGFR by immunohistochemistry, performance status of 0 to 2, and measurable disease received paclitaxel 225 mg/m2with carboplatin area under the curve = 6 on day 1 every 3 weeks. Cetuximab was administered at 400 mg/m2, 1 week before paclitaxel and carboplatin, then weekly at 250 mg/m2. The regimen continued until disease progression or intolerable toxicity.

Results

Thirty-one of 32 enrolled patients were treated. The most common cetuximab toxicity was rash in 84% of patients (grade 3 in 13%). Pharmacokinetic sampling did not reveal an interaction between carboplatin, paclitaxel, and cetuximab. An objective response was observed in eight patients (26%). With a median follow-up of 19 months, the median time to progression was 5 months, median survival was 11 months, and the 1- and 2-year survival rates were 40% and 16%, respectively.

Conclusion

The combination of cetuximab, paclitaxel, and carboplatin was safe and well tolerated in this population of stage IV patients. The response rate, time to progression, and median survival were slightly superior to historical controls treated with paclitaxel and carboplatin alone. A randomized phase II trial has completed accrual.
Demilune Cell and Parotid Protein from Murine Oviductal Epithelium Stimulates Preimplantation Embryo Development
Authors: Lee Kai-Fai , Xu Jia-Sen , Lee Yin-Lau , Yeung William S. B.
Published: October 2005

In mammals, fertilization and early preimplantation embryo development occur in the oviduct. We hypothesized that interaction exists between the developing embryos and the maternal genital tract, such that the embryos modulate the physiology and gene expression of the oviduct so that it is conducive to their development. By comparing the gene expression patterns in mouse oviducts containing transferred preimplantation embryos with those of oviducts containing oocytes, we report here the characterization of demilune cell and parotid protein (Dcpp), which was up-regulated in the embryo-containing oviduct. Dcpp mRNA was highly expressed in the oviductal epithelium at the estrus stage. The Dcpp gene codes for a protein of 150 amino acids and contains a signal peptide suggestive of secretory function. The Dcpp mRNA level was maintained in the oviductal epithelium of pregnant females but decreased continuously in those of pseudopregnant mice. Exogenous estrogen stimulated the expression of Dcpp mRNA and protein in ovariectomized mice. The effect was abolished by an estrogen antagonist, ICI 182,780. Dcpp protein was present in mouse oviductal fluid but not in uterine fluid. More importantly, Dcpp immunoreactivity was found in embryos recovered from the oviduct but not in mature oocytes from the ovary. Supplementation of Dcpp to culture medium stimulated the development of mouse embryos to the blastocyst stage. Anti-Dcpp antibody decreased the beneficial effect of Dcpp on implantation of two-cell mouse embryos transferred to the oviducts of the foster mothers. In summary, our data demonstrated that Dcpp is highly expressed in the oviductal lumen in the presence of preimplantation embryos. It stimulates the growth of preimplantation embryos and may play an important role in embryo-maternal dialogue.
Estradiol Regulates Different Genes in Human Breast Tumor Xenografts Compared with the Identical Cells in Culture
Authors: Harvell Djuana M. E. , Richer Jennifer K. , Allred D. Craig , Sartorius Carol A. , Horwitz Kathryn B.
Published: October 2005

In breast cancers, estrogen receptor (ER) levels are highly correlated with response to endocrine therapies. We sought to define mechanisms of estrogen (E) signaling in a solid breast tumor model using gene expression profiling. ER+ T47D-Y human breast cancer cells were grown as xenografts in ovariectomized nude mice under four conditions: 1) 17β-estradiol for 8 wk (E); 2) without E for 8 wk (control); 3) E for 7 wk followed by 1 wk of E withdrawal (Ewd); or 4) E for 8 wk plus tamoxifen for the last week. E-regulated genes were defined as those that differed significantly between control and E and/or between E and Ewd or control and Ewd. These protocols generated 188 in vivo E-regulated genes that showed two major patterns of regulation. Approximately 46% returned to basal states after Ewd (class I genes); 53% did not (class II genes). In addition, more than 70% of class II-regulated genes also failed to reverse in response to tamoxifen. These genes may be interesting for the study of hormone-resistance issues. A subset of in vivo E-regulated genes appears on lists of clinical ER discriminator genes. These may be useful therapeutic targets or markers of E activity. Comparison of in vivo E-regulated genes with those regulated in identical cells in vitro after 6 and 24 h of E treatment demonstrate only 11% overlap. This indicates the extent to which gene expression profiles are uniquely dependent on hormone-treatment times and the cellular microenvironment.
Activation of a Neural Brain-Testicular Pathway Rapidly Lowers Leydig Cell Levels of the Steroidogenic Acute Regulatory Protein and the Peripheral-Type Benzodiazepine Receptor while Increasing Levels of Neuronal Nitric Oxide Synthase
Authors: Herman Melissa , Rivier Catherine
Published: October 2005

Activation of a neural brain-testicular pathway by the intracerebroventricular injection of the β-adrenergic agonist isoproterenol (ISO), the hypothalamic peptide corticotropin-releasing factor (CRF), or alcohol (EtOH) rapidly decreases the testosterone (T) response to human chorionic gonadotropin. To elucidate the intratesticular mechanisms responsible for this phenomenon, we investigated the influence of intracerebroventricular-injected ISO, CRF, or EtOH on levels of the steroidogenic acute regulatory (StAR) protein, the peripheral-type benzodiazepine receptor (PBR), and the cytochrome P450 side-chain cleavage enzyme in semipurified Leydig cells. ISO (10 μg), CRF (5 μg), or EtOH (5 μl of 200 proof, a dose that does not induce neuronal damage nor leaks to the periphery) rapidly decreased StAR and PBR but not cytochrome P450 side-chain cleavage enzyme protein levels. Levels of the variant of the neuronal nitric oxide synthase (nNOS) that is restricted to Leydig cells, TnNOS, significantly increased in response to ISO, CRF, and EtOH over the time course of altered StAR/PBR concentrations. However, pretreatment of the rats with Nwnitro-arginine methylester, which blocked ISO-induced increases in TnNOS, neither restored the T response to human chorionic gonadotropin nor prevented the decreases in StAR and PBR. These results provide evidence of concomitant changes in Leydig cell StAR and PBR levels in live rats. They also indicate that activation of a neural brain-testicular pathway rapidly decreases concentrations of these steroidogenic proteins while up-regulating testicular NO production. However, additional studies are necessary to elucidate the functional role played by this gas in our model.
Changes in Tight Junctional Resistance of the Cervical Epithelium Are Associated with Modulation of Content and Phosphorylation of Occludin 65-Kilodalton and 50-Kilodalton Forms
Authors: Zhu Ling , Li Xin , Zeng Robin , Gorodeski George I.
Published: October 2005

Treatment of human cervical epithelial CaSki cells with ATP or with the diacylglyceride sn-1,2-dioctanoyl diglyceride (diC8) induced a staurosporine-sensitive transient increase, followed by a late decrease, in tight-junctional resistance (RTJ). CaSki cells express two immunoreactive forms of occludin, 65 and 50 kDa. Treatments with ATP and diC8 decreased the density of the 65-kDa form and increased the density of the 50-kDa form. ATP also decreased threonine phosphorylation of the 65-kDa form and increased threonine phosphorylation of the 50-kDa form and tyrosine phosphorylation of the 65- and 50-kDa forms. Staurosporine decreased acutely threonine and tyrosine phosphorylation of the two isoforms and in cells pretreated with staurosporine ATP increased acutely the density of the 65-kDa form and threonine phosphorylation of the 65-kDa form. Treatment with N-acetyl-leucinyl-leucinyl-norleucinal increased the densities of the 65- and 50-kDa forms. Pretreatment with N-acetyl-leucinyl-leucinyl-norleucinal attenuated the late decreases in RTJ induced by ATP and diC8 and the decrease in the 65-kDa and increase in the 50-kDa forms induced by ATP. Correlation analyses showed that high levels of RTJ correlated with the 65-kDa form, whereas low levels of RTJ correlated negatively with the 65-kDa form and positively with the 50-kDa form. The results suggest that in CaSki cells 1) occludin determines gating of the tight junctions, 2) changes in occludin phosphorylation status and composition regulate the RTJ, 3) protein kinase-C-mediated, threonine dephosphorylation of the 65-kDa occludin form increases the resistance of assembled tight junctions, 4) the early stage of tight junction disassembly involves calpain-mediated breakdown of occludin 65-kDa form to the 50-kDa form, and 5) increased levels of the 50-kDa form interfere with occludin gating of the tight junctions.
MED14 and MED1 Differentially Regulate Target-Specific Gene Activation by the Glucocorticoid Receptor
Authors: Chen Weiwei , Rogatsky Inez , Garabedian Michael J.
Published: October 2005

The Mediator subunits MED14 and MED1 have been implicated in transcriptional regulation by the glucocorticoid receptor (GR) by acting through its activation functions 1 and 2. To understand the contribution of these Mediator subunits to GR gene-specific regulation, we reduced the levels of MED14 and MED1 using small interfering RNAs in U2OS-hGR osteosarcoma cells and examined the mRNA induction by dexamethasone of four primary GR target genes, interferon regulatory factor 8 (IRF8), ladinin 1, IGF-binding protein 1 (IGFBP1), and glucocorticoid-inducible leucine zipper (GILZ). We found that the GR target genes differed in their requirements for MED1 and MED14. GR-dependent mRNA expression of ladinin 1 and IRF8 required both MED1 and MED14, whereas induction of IGFBP1 mRNA by the receptor was dependent upon MED14, but not MED1. In contrast, GILZ induction by GR was largely independent of MED1 and MED14, but required the p160 cofactor transcriptional intermediary factor 2. Interestingly, we observed higher GR occupancy at GILZ than at the IGFBP1 or IRF8 glucocorticoid response element (GREs). In contrast, recruitment of MED14 compared with GR at IGFBP1 and IRF8 was higher than that observed at GILZ. At GILZ, GR and RNA polymerase II were recruited to both the GRE and the promoter, whereas at IGFBP1, RNA polymerase II occupied the promoter, but not the GRE. Thus, MED14 and MED1 are used by GR in a gene-specific manner, and the requirement for the Mediator at GILZ may be bypassed by increased GR and RNA polymerase II occupancy at the GREs. Our findings suggest that modulation of the Mediator subunit activities would provide a mechanism for promoter selectivity by GR.
Codependence of Growth Hormone-Responsive, Sexually Dimorphic Hepatic Gene Expression on Signal Transducer and Activator of Transcription 5b and Hepatic Nuclear Factor 4α
Authors: Holloway Minita G. , Laz Ekaterina V. , Waxman David J.
Published: October 2005

Targeted disruption of the signal transducer and activator of transcription 5b gene (STAT5b) leads to decreased expression in male mouse liver of a male-predominant cytochrome (Cyp) 2d protein, whereas female-predominant Cyp2b proteins are increased. Presently, we characterize the effects of STAT5b deficiency on 15 specific, individual Cyp RNAs and other sexually dimorphic liver gene products. All seven male-specific RNAs investigated were decreased to normal female levels in STAT5b-deficient male liver, whereas five of eight female-specific RNAs, designated class I female genes, were increased in expression up to 200-fold or more. STAT5b deficiency had a much more modest effect on the expression of these genes in females. Hypophysectomy and GH replacement studies demonstrated positive GH pulse regulation of all seven male RNAs and negative GH pulse regulation of class I, but not class II, female RNAs in wild-type, but not in STAT5b-deficient, male mice. A majority of the sex-specific genes responded in parallel to the loss of STAT5b and the loss of hepatocyte nuclear factor 4α, indicating that both transcription factors are essential and suggesting they may coregulate sexually dimorphic liver gene expression. Continuous GH treatment of intact male mice, which overrides the endogenous male, pulsatile plasma GH pattern, down-regulated all seven male RNAs and induced expression of the five class I female RNAs within 4–7 d; however, induction of class II female RNAs was delayed until d 7–14. Given the slow responses of all 15 genes to changes in plasma GH status, GH regulation of sex-specific Cyp expression is proposed to be indirect and mediated by STAT5b- and hepatocyte nuclear factor 4α-dependent factors that may include repressors of female-specific Cyps and other targets of GH action.
Shroom regulates epithelial cell shape via the apical positioning of an actomyosin network
Authors: Hildebrand Jeffrey D.
Published: October 2005

The actin-binding protein Shroom is essential for neural tube morphogenesis in multiple vertebrate organisms, indicating its function is evolutionarily conserved. Shroom facilitates neurulation by regulating the morphology of neurepithelial cells. Shroom localizes to the apical tip of adherens junctions of neural ectoderm cells in vivo and to the apical junctional complex (AJC) in MDCK cells. Induced expression of Shroom in polarized epithelia elicits apical constriction and dramatic reorganization of the apical arrangement and packing of cells without altering apical-basal polarity. These events likely mimic the cell shape changes and cellular movements required for neurulation in vivo. The observed phenotypes depend on the ability of Shroom to alter F-actin distribution and regulate the formation of a previously uncharacterized contractile actomyosin network associated with the AJC. Targeting the C-terminal domain of Shroom to the apical plasma membrane elicits constriction and reorganization of the actomyosin network, indicting that this domain mediates Shroom's activity. In vivo, Shroom-mutant neural epithelia show a marked reduction in apically positioned myosin. Thus, Shroom likely facilitates neural tube closure by regulating cell shape changes via the apical positioning of an actomyosin network in the neurepithelium.
Fundamentally different roles for LFA-1, Mac-1 and α4-integrin in neutrophil chemotaxis
Authors: Heit Bryan , Colarusso Pina , Kubes Paul
Published: October 2005

Although the LFA-1, Mac-1 and α4 integrins are required for chemotaxis, it is unknown how they are regulated or what specific role they play. Previously we demonstrated that fMLP and IL-8 induce chemotaxis via the p38 MAPK and phosphoinositide 3-kinase (PI3K) pathways, respectively. Here we show that these chemoattractants also activate and use Mac-1 and LFA-1 in a differential manner during chemotaxis. Using integrin-specific substrata, we demonstrate that cell movement in response to IL-8 is mediated by Mac-1, whereas LFA-1 is required for directional migration. By contrast, chemotaxis to fMLP requires Mac-1 for cell movement, whereas LFA-1 and α4-integrin are required for directional migration. On serum protein, which contains ligands for LFA-1, Mac-1 and α4-integrin, chemotaxis to fMLP is dependent on Mac-1, whereas chemotaxis to IL-8 is dependent on LFA-1. These results suggest that Mac-1 is the dominant integrin involved in chemotaxis to fMLP, and LFA-1 is the dominant integrin involved in chemotaxis to IL-8. Consistent with these observations, higher quantities of high-affinity Mac-1 are found on cells chemotaxing to fMLP then on cells chemotaxing to IL-8. Moreover, a much larger quantity of clustered LFA-1 was found on cells migrating to IL-8 compared to cells moving towards fMLP. When cells are presented with competing gradients of fMLP and IL-8, they preferentially migrate towards fMLP and activate/utilize integrins in a manner identical to fMLP alone. Under the same conditions, p38 MAPK inhibition abolishes the preferential migration to fMLP; instead, the cells migrate preferentially towards IL-8. The activation and utilization of integrins under these conditions are consistent with patterns observed with IL-8 alone. Together, these data suggest that fMLP and IL-8 differentially activate integrins for use during chemotaxis, that p38 MAPK is a major mediator in the activation and utilization of integrins, and selective integrin activation occurs during chemotaxis between opposing gradients.
Distribution and dynamics of Lamp1-containing endocytic organelles in fibroblasts deficient in BLOC-3
Authors: Falcón-Pérez Juan M. , Nazarian Ramin , Sabatti Chiara , Dell'Angelica Esteban C.
Published: October 2005

Late endosomes and lysosomes of mammalian cells in interphase tend to concentrate in the perinuclear region that harbors the microtubule-organizing center. We have previously reported abnormal distribution of these organelles – as judged by reduced percentages of cells displaying pronounced perinuclear accumulation – in mutant fibroblasts lacking BLOC-3 (for `biogenesis of lysosome-related organelles complex 3'). BLOC-3 is a protein complex that contains the products of the genes mutated in Hermansky-Pudlak syndrome types 1 and 4. Here, we developed a method based on image analysis to estimate the extent of organelle clustering in the perinuclear region of cultured cells. Using this method, we corroborated that the perinuclear clustering of late endocytic organelles containing Lamp1 (for `lysosome-associated membrane protein 1') is reduced in BLOC-3-deficient murine fibroblasts, and found that it is apparently normal in fibroblasts deficient in BLOC-1 or BLOC-2, which are another two protein complexes associated with Hermansky-Pudlak syndrome. Wild-type and mutant fibroblasts were transfected to express human LAMP1 fused at its cytoplasmic tail to green fluorescence protein (GFP). At low expression levels, LAMP1-GFP was targeted correctly to late endocytic organelles in both wild-type and mutant cells. High levels of LAMP1-GFP overexpression elicited aberrant aggregation of late endocytic organelles, a phenomenon that probably involved formation of anti-parallel dimers of LAMP1-GFP as it was not observed in cells expressing comparable levels of a non-dimerizing mutant variant, LAMP1-mGFP. To test whether BLOC-3 plays a role in the movement of late endocytic organelles, time-lapse fluorescence microscopy experiments were performed using live cells expressing low levels of LAMP1-GFP or LAMP1-mGFP. Although active movement of late endocytic organelles was observed in both wild-type and mutant fibroblasts, quantitative analyses revealed a relatively lower frequency of microtubule-dependent movement events, either towards or away from the perinuclear region, within BLOC-3-deficient cells. By contrast, neither the duration nor the speed of these microtubule-dependent events seemed to be affected by the lack of BLOC-3 function. These results suggest that BLOC-3 function is required, directly or indirectly, for optimal attachment of late endocytic organelles to microtubule-dependent motors.
Effects of intake rate on energy expenditure, somatic repair and reproduction of zebra finches
Authors: Wiersma Popko , Verhulst Simon
Published: October 2005

Understanding the effect of food availability on food requirements is critical when linking food availability e.g. to reproduction or habitat selection. Decreasing intake rate (intake per unit foraging effort) can be expected to increase daily energy expenditure (DEE), due to increased foraging costs. However, all the studies we could find that have tested this hypothesis(with one exception) found DEE to be constant or decreasing when intake rate was experimentally decreased. This may be due to the design of the reward schedule, which can be fixed (e.g. 20 units effort required for each reward)or variable (e.g. each unit effort rewarded with probability 1/20). Most studies used fixed reward rates, but foraging motivation is generally higher for variable reward rates, and the only study in which animals increased DEE when intake rate decreased used variable reward rates. To assess the generality of this result, we exposed zebra finches Taeniopygia guttata to different intake rates using variable reward rates.We decreased intake rate by mixing 25 g of seeds with 0, 25 or 75 g of chaff. With increasing chaff/seed ratio the time spent foraging increased from 6% to 27%, but this was insufficient to compensate for the lower intake rate,because DEE decreased by 6.6%. Body mass was independent of chaff/seed ratio. Effects of intake rate on foraging time and DEE were stronger at lower temperatures, when DEE was higher. The decrease in DEE in adverse conditions raises the question of what prevents such behaviour in benign circumstances.

We hypothesize that energy is saved at the expense of `condition', and we tested this hypothesis in two ways. Firstly, we tested the effect of intake rate on the replacement of two plucked tail feathers (a form of somatic repair). Replacement feathers were shorter when intake rate was low,indicating an effect of intake rate on somatic repair ability. Secondly, we tested for carry-over effects of intake rate on reproduction, by giving pairs the opportunity to reproduce with access ad libitum to food after feeding on one of the three chaff/seed ratios for 6 weeks. The interval until laying the first egg increased with decreasing intake rate in the preceding 6 weeks. The effects of intake rate on somatic maintenance and reproduction may explain why birds sustained higher metabolic rates than apparently necessary,but the physiological mechanisms determining the optimal metabolic rate remain to be discovered.
Metabolic adjustments to increasing foraging costs of starlings in a closed economy
Authors: Wiersma Popko , Salomons H. Martijn , Verhulst Simon
Published: October 2005

Knowledge of the physiological consequences of variation in food availability may be essential for understanding behavioural and life history responses to such variation. To study the physiological consequences of food availability animals are generally subjected to caloric restriction or starvation, thereby reducing the upper limit to the energy budget. The relevance of this approach to free-living animals is questionable, however,because under natural conditions low food availability often results in higher foraging costs, and everything else remaining equal this results in a higher energy budget. We manipulated food availability by varying the foraging costs and studied effects on daily energy expenditure (DEE) and energy allocation of captive starlings Sturnus vulgaris. Birds in a closed economy earned their food by flying between two perches 5 m apart. The probability of a reward was set at three different levels, thereby creating a `poor',`intermediate' and `rich' environment. Compared with the rich environment,birds flew 4 times more (2.3 h per day) in the poor environment, and increased DEE by 43% to 220 kJ day-1 (3.7×BMR), within the range of free-living parents rearing young. To our knowledge this is the first study to show an increase in DEE with decreasing food availability. Body mass, basal metabolic rate (BMR) and pectoral muscle size were reduced in the poor environment. Nocturnal energy expenditure was further reduced by reaching BMR earlier in the night. Calculations show that the energy demands in the poor environment could not be met with the flight costs of 20.5 W that we measured previously in a rich environment. Flight costs derived indirectly from the energy budget were lower, at 17.5 W, probably due to lower body mass. By reducing body mass by 20%, and economising during sleep, the birds achieved savings of 37% in their DEE. Without these savings, a DEE substantially higher than measured in free-living parents rearing young would be required to remain in energy balance. Surprisingly little data exist to verify whether free-living animals use the same tactics to survive periods with low food availability.
Calcium-activated potassium channel of the tobacco hornworm,Manduca sexta: molecular characterization and expression analysis
Authors: Keyser Matthew R. , Witten Jane L.
Published: October 2005

Large-conductance calcium- and voltage-gated potassium channels (BK or Slowpoke) serve as dynamic integrators linking electrical signaling and intracellular activity. These channels can mediate many different Ca2+-dependent physiological processes including the regulation of neuronal and neuroendocrine cell excitability and muscle contraction. To gain insights into the function of BK channels in vivo, we isolated a full-length cDNA encoding the alpha subunit of a Slowpoke channel from the tobacco hornworm, Manduca sexta (msslo). Amino acid sequence comparison of the deduced Manduca protein revealed at least 80%identity to the insect Slo channels. The five C-terminal alternative splice regions are conserved, but the cloned cDNA fragments contained some unique combinations of exons E, G and I. Our spatial profile revealed that transcript levels were highest in skeletal muscle when compared with the central nervous system (CNS) and visceral muscle. The temporal profile suggested that msslo expression is regulated developmentally in a tissue- and regional-specific pattern. The levels of msslo transcripts remain relatively constant throughout metamorphosis in the CNS, transiently decline in the heart and are barely detectable in the gut except in adults. A dramatic upregulation of msslo transcript levels occurs in thoracic but not abdominal dorsal longitudinal body wall muscles (DLM), suggesting that the msSlo current plays an important role in the excitation or contractile properties of the phasic flight muscle. Our developmental profile of msslo expression suggests that msSlo currents may contribute to the changes in neural circuits and muscle properties that produce stage-specific functions and behaviors.