bluuebunny/crossref_metadata_2025 huggingface dataset:
Precision and accuracy of Morgan ventilometers at continuous and sinusoidal flows
Authors: Hart JD , Withers RT , Tucker RC
Published: December 2003

The P.K. Morgan Mark II Ventilometer comprises a turbine transducer and a control/readout unit, which contains either a VENTX5A or VENTX6A programme. This equipment is used to measure minute ventilation during oxygen consumption tests. The precision and accuracy of six of these devices (a VENTX5A with two turbines, and two VENTX6As each with two different turbines) were examined during continuous and pulsatile flows; accuracy was affected by the syringe rate during the calibration procedure. The reference standard was a 350 l Collins chain-compensated gasometer. At continuous flows, the two VENTX5A devices showed accuracies of 99.5-100.5% over the range 60-160 l.min-1 whereas those for the four VENTX6As were 99.3-102.1% over the range 60-200 l.min-1. The mean accuracies of sinusoidal flows for the VENTX5A ranged between 96.1-101.3% for minute volumes spanning 15-200 l.min-1; comparable data for the VENTX6As were 95.9-98.9%. These mean accuracies improved to 98.1-101.3% for the VENTX5A at measured minute volumes > 80 l.min-1. Omission of the two lowest tidal volumes (1 and 1.5 l) for the VENTX6As narrowed the range of accuracy to 96.9-98.5%. The coefficients of variation for five trials at each minute ventilation were 0-0.2%. We conclude that, while the P.K. Morgan Mark II Ventilometer has excellent precision, its accuracy is dependent on the calibration syringe rate, minute ventilation and program.
Bronchiolitis obliterans: the lone manifestation of rheumatoid arthritis?
Authors: Schwarz MI , Lynch DA , Tuder R
Published: December 2003

The patient was a 62 year old man, who suddenly developed obstructive lung disease without a readily definable cause. He had a remarkable family history of deforming rheumatoid arthritis, and a serum rheumatoid factor of 1:1,256, but with no evidence of active rheumatological disease. Clinical, physiological and radiologic features suggested bronchiolitis obliterans, and this was confirmed by open lung biopsy. Immune staining of tissue revealed immunoglobulin M (IgM) as well as rare immunoglobulin (IgG) containing plasma cells in a peribronchiolar location. Because of these findings, we suggest that this case represents bronchiolitis obliterans secondary to a rheumatoid process. This case is unusual since it appeared in a man and is the first and, so far, the only manifestation of rheumatoid arthritis. Prior studies indicate that the bronchiolitis obliterans of rheumatoid arthritis occurs primarily in women and only in ongoing cases.
Successful treatment of AIDS-related pulmonary Kaposi's sarcoma with liposomal daunorubicin
Authors: Schurmann D , Dormann A , Grunewald T , Ruf B
Published: December 2003

We report a 35 year old male, human immunodeficiency virus (HIV)-infected patient with acquired immune deficiency syndrome (AIDS), who presented with rapidly progressive pulmonary Kaposi's sarcoma. The tumour regressed with treatment with liposomal daunorubicin and remained in partial remission until the patient died 12 months later from complications of HIV infection. Liposomal daunorubicin may be a safe and effective alternative to the treatment protocols in current use for pulmonary Kaposi's sarcoma.
A rare case of inflammatory pseudotumour of the bronchus, occurring in an achondroplastic woman
Authors: Vanderheyden M , Van Meerbeeck J , Van Bouwel E , Bosmans V , Colpaert C , Ramael M , Van Marck E
Published: December 2003

An inflammatory pseudotumour of the lung in an achondroplastic woman is described. The occurrence of both conditions in the same patient probably represents a coincidental finding. However, recurrent pulmonary infections, as frequently seen in achondroplasia, may be relevant, because a history of antecedent infection is noted in one third of cases of inflammatory pseudotumours. Despite extensive debridement of the pseudotumour by neodymium yttrium aluminium garnet (NdYAG) laser therapy, early recurrence occurred.
Constitutive and regulated expression of platelet basic protein in human monocytes
Authors: El-Gedaily Ahmed , Schoedon Gabriele , Schneemann Markus , Schaffner Andreas
Published: December 2003

Platelet basic protein (PBP) and several of its derivatives are known for their broad range of functions as signaling molecules and cationic antimicrobial peptides and were considered hitherto megakaryocyte- and platelet-specific. In search of glucocorticoid-regulated antimicrobial systems of monocytes, we found a 15-fold down-regulation of PBP mRNA by differential display. Regulation was confirmed in vivo even at low prednisone doses. Quantitative mRNA analyses confirmed down-regulation also for platelets. Western blotting and immunostains showed down-regulation at the protein level. Pro-PBP derivatives were in the size range of 7.5-14 kD and in immunostains, gave granular cytoplasmatic patterns. Interleukin (IL)-4 and IL-10 induced a similar down-regulation. Phagocytosis resulted in an increase of smaller derivatives in the range of 7.5 kD. Stimulation with interferon-γ and lipopolysaccharide did decrease expression of PBP and affected derivatization. Expression of PBP and its derivatives is not restricted to the megakaryocytic cell lineage. PBP and some of its derivatives might contribute to the antimicrobial armamentarium of mononuclear phagocytes or have monokine functions. Our studies define PBPs as one among the many immunosuppressive targets of glucocorticoids.
Critical role of CXC chemokines in endotoxemic liver injury in mice
Authors: Li Xiang , Klintman Daniel , Liu Qing , Sato Tohru , Jeppsson Bengt , Thorlacius Henrik
Published: December 2003

Tissue accumulation of leukocytes constitutes a rate-limiting step in endotoxin-induced tissue injury. Chemokines have the capacity to regulate leukocyte trafficking. However, the role of CXC chemokines, i.e., macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (KC), in leukocyte recruitment, microvascular perfusion failure, cellular injury, and apoptosis in the liver remains elusive. Herein, mice were challenged with lipopolysaccharide (LPS) in combination with D-galactosamine, and intravital microscopy of the liver microcirculation was conducted 6 h later. It was found that immunoneutralization of MIP-2 and KC did not reduce LPS-induced leukocyte rolling and adhesion in postsinusoidal venules. In contrast, pretreatment with monoclonal antibodies against MIP-2 and KC abolished (83% reduction) extravascular recruitment of leukocytes in the livers of endotoxemic mice. Notably, endotoxin challenge increased the expression of CXC chemokines, which was mainly confined to hepatocytes. Moreover, endotoxin-induced increases of liver enzymes and hepatocellular apoptosis were decreased by more than 82% and 68%, respectively, and sinusoidal perfusion was restored in mice passively immunized against MIP-2 and KC. In conclusion, this study indicates that intravascular accumulation of leukocytes in the liver is independent of CXC chemokines in endotoxemic mice. Instead, our novel data suggest that CXC chemokines are instrumental in regulating endotoxin-induced transmigration and extravascular tissue accumulation of leukocytes. Indeed, these findings demonstrate that interference with MIP-2 and KC functions protects against septic liver damage and may constitute a potential therapeutic strategy to control pathological inflammation in endotoxemia.
Functional regulation of GATA-2 by acetylation
Authors: Hayakawa Fumihiko , Towatari Masayuki , Ozawa Yukiyasu , Tomita Akihiro , Privalsky Martin L , Saito Hidehiko
Published: December 2003

The transcription factor GATA-2 is expressed in hematopoietic stem and progenitor cells and is functionally implicated in their survival and proliferation. In the present study, we show that GATA-2 exists as an acetylated protein in immature precursor cells, KG1. GATA-2 was acetylated in vitro by p300 and GCN5. We have identified multiple acetylation sites by p300 on GATA-2, which include sites outside the zinc finger domain. We confirmed that GATA-2 acetylation occurred in transiently transfected 293T cells at sites similar to those induced by p300 in vitro. We have successfully shown that acetylation of GATA-2 in vitro increased its DNA-binding activity. In addition, GATA-2 displayed a transcriptional synergism with p300 that was impaired by mutation of each acetylation site. More importantly, each mutation in the acetylation sites of GATA-2 abolished its growth inhibitory effect on an interleukin-3-dependent progenitor, 32D. We conclude that acetylation provides multiple control points for the regulation of GATA-2 function.
Highly purified lipoteichoic acid activates neutrophil granulocytes and delays their spontaneous apoptosis via CD14 and TLR2
Authors: Lotz Sonja , Aga Eresso , Wilde Inga , van Zandbergen Ger , Hartung Thomas , Solbach Werner , Laskay Tamás
Published: December 2003

Lipoteichoic acid (LTA) is a major component of the cell membrane of gram-positive bacteria. Although LTA has become increasingly recognized as an immunomodulator, its effect on polymorphonuclear neutrophil granulocytes (PMN) is still not clear. The interaction between LTA and PMN, however, is of particular importance, as PMN are the first leukocytes that migrate to the site of infection and encounter bacterial pathogens. In the present study, the interaction of highly purified human PMN with endotoxin-free LTA from Staphylococcus aureus was investigated. After exposure to LTA, neutrophil granulocytes acquired typical activated cell morphology. LTA had a marked activating effect on the functions of PMN as well. Shedding of CD62L, degranulation, and priming for formyl-Met-Leu-Phe-mediated oxidative burst were induced in PMN upon exposure to LTA. Moreover, LTA treatment induced the release of proinflammatory cytokines such as interleukin-8, tumor necrosis factor α, and granulocyte-colony stimulating factor by PMN. The effects of LTA on PMN were found to be associated with nuclear factor-κB activation. Of particular interest was that LTA inhibited the spontaneous apoptosis and therefore, increased the lifespan of PMN. Experiments using blocking antibodies revealed that CD14 and Toll-like receptor 2 (TLR2) but not TLR4 play a major role in LTA-mediated effects on PMN. These data clearly show that LTA, a component of gram-positive bacteria, directly activates neutrophil granulocytes, the primary effector cells in the first line of defense against infectious challenge.
Extracellular and intracellular decoys in the tuning of inflammatory cytokines and Toll-like receptors: the new entry TIR8/SIGIRR
Authors: Mantovani Alberto , Locati Massimo , Polentarutti Nadia , Vecchi Annunciata , Garlanda Cecilia
Published: December 2003

Following the identification of the interleukin (IL)-1 type II receptor as a prototypic decoy receptor, nonsignaling receptors with decoy functions have been identified for members of the IL-1/IL-18,tumor necrosis factor, IL-10, and IL-13 receptor families. Moreover, the silent receptor D6 is a promiscuous decoy and scavenger receptor of inflammatory chemokines. The type II IL-1 decoy receptor also acts as a dominant-negative molecule. Intracellular pathways of inhibition of IL-1 and Toll-like receptor (TLR) signaling have been identified. In particular, recent results suggest that the Toll/IL-1 receptor (TIR) family member TIR8, also known as single immunoglobulin IL-1-related receptor (SIGIRR), is a negative regulator of IL-1 and TLR signaling. Thus, extracellular and intracellular decoys tune the activation of members of the IL-1/TLR receptor family.
Docetaxel and Cisplatin With Granulocyte Colony-Stimulating Factor (G-CSF) Versus MVAC With G-CSF in Advanced Urothelial Carcinoma: A Multicenter, Randomized, Phase III Study From the Hellenic Cooperative Oncology Group
Authors: Bamias A. , Aravantinos G. , Deliveliotis C. , Bafaloukos D. , Kalofonos C. , Xiros N. , Zervas A. , Mitropoulos D. , Samantas E. , Pectasides D. , Papakostas P. , Gika D. , Kourousis C. , Koutras A. , Papadimitriou C. , Bamias C. , Kosmidis P. , Dimopoulos M.A.
Published: December 2003

Purpose

The combination of methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC) represents the standard regimen for inoperable or metastatic urothelial cancer, but its toxicity is significant. We previously reported a 52% response rate (RR) using a docetaxel and cisplatin (DC) combination. The toxicity of this regimen compared favorably with that reported for MVAC. We thus designed a randomized phase III trial to compare DC with MVAC.

Patients and Methods

Patients with inoperable or metastatic urothelial carcinoma; adequate bone marrow, renal, liver, and cardiac function; and Eastern Cooperative Oncology Group performance status ≤ 2 were randomly assigned to receive MVAC at standard doses or docetaxel 75 mg/m2 and cisplatin 75 mg/m2 every 3 weeks. All patients received prophylactic granulocyte colony-stimulating factor (G-CSF) support.

Results

Two hundred twenty patients were randomly assigned (MVAC, 109 patients; DC, 111 patients). Treatment with MVAC resulted in superior RR (54.2% v 37.4%; P = .017), median time to progression (TTP; 9.4 v 6.1 months; P = .003) and median survival (14.2 v 9.3 months; P = .026). After adjusting for prognostic factors, difference in TTP remained significant (hazard ratio [HR], 1.61; P = .005), whereas survival difference was nonsignificant at the 5% level (HR, 1.31; P = .089). MVAC caused more frequent grade 3 or 4 neutropenia (35.4% v 19.2%; P = .006), thrombocytopenia (5.7% v 0.9%; P = .046), and neutropenic sepsis (11.6% v 3.8%; P = .001). Toxicity of MVAC was considerably lower than that previously reported for MVAC administered without G-CSF.

Conclusion

MVAC is more effective than DC in advanced urothelial cancer. G-CSF-supported MVAC is well tolerated and could be used instead of classic MVAC as first-line treatment in advanced urothelial carcinoma.
Adjuvant Interferon in High-Risk Melanoma: The AIM HIGH Study—United Kingdom Coordinating Committee on Cancer Research Randomized Study of Adjuvant Low-Dose Extended-Duration Interferon Alfa-2a in High-Risk Resected Malignant Melanoma
Authors: Hancock B.W. , Wheatley K. , Harris S. , Ives N. , Harrison G. , Horsman J.M. , Middleton M.R. , Thatcher N. , Lorigan P.C. , Marsden J.R. , Burrows L. , Gore M.
Published: December 2003

Purpose

To evaluate low-dose extended duration interferon alfa-2a as adjuvant therapy in patients with thick (≥ 4 mm) primary cutaneous melanoma and/or locoregional metastases.

Patients and Methods

In this randomized controlled trial involving 674 patients, the effect of interferon alfa-2a (3 megaunits three times per week for 2 years or until recurrence) on overall survival (OS) and recurrence-free survival (RFS) was compared with that of no further treatment in radically resected stage IIB and stage III cutaneous malignant melanoma.

Results

The OS and RFS rates at 5 years were 44% (SE, 2.6) and 32% (SE, 2.1), respectively. There was no significant difference in OS or RFS between the interferon-treated and control arms (odds ratio [OR], 0.94; 95% CI, 0.75 to 1.18; P = .6; and OR, 0.91; 95% CI, 0.75 to 1.10; P = .3; respectively). Male sex (P = .003) and regional lymph node involvement (P = .0009), but not age (P = .7), were statistically significant adverse features for OS. Subgroup analysis by disease stage, age, and sex did not show any clear differences between interferon-treated and control groups in either OS or RFS. Interferon-related toxicities were modest: grade 3 (and in only one case, grade 4) fatigue or mood disturbance was seen in 7% and 4% respectively, of patients. However, there were 50 withdrawals (15%) from interferon treatment due to toxicity.

Conclusion

The results from this study, taken in isolation, do not indicate that extended-duration low-dose interferon is significantly better than observation alone in the initial treatment of completely resected high-risk malignant melanoma.
Cost-Utility Analysis of Preoperative Radiotherapy in Patients With Rectal Cancer Undergoing Total Mesorectal Excision: A Study of the Dutch Colorectal Cancer Group
Authors: van den Brink Mandy , van den Hout Wilbert B. , Stiggelbout Anne M. , Klein Kranenbarg Elma , Marijnen Corrie A.M. , van de Velde Cornelis J.H. , Kievit Job
Published: December 2003

Purpose

To compare the societal costs and the (quality-adjusted) life expectancy of patients with rectal cancer undergoing total mesorectal excision (TME) with or without short-term preoperative radiotherapy (5 × 5 Gy).

Patients and Methods

We used a Markov model to project the clinical and economic outcomes of preoperative radiotherapy. Data on local recurrence rates, quality of life, and costs were obtained from the patients of a multicenter randomized clinical trial. In this trial, 1,861 patients with resectable rectal cancer from 108 hospitals were randomly assigned for TME surgery with or without preoperative radiotherapy. Outcome measures of the model were life expectancy, quality-adjusted life expectancy, lifetime costs per patient, and the incremental cost-effectiveness ratio.

Results

The base case model estimates that the loss of quality of life due to preoperative radiotherapy is outweighed by the gain in life expectancy. Life expectancy increases by 0.67 years; quality-adjusted life expectancy, by 0.39 years; and costs, by $9,800 per patient. The corresponding cost-effectiveness ratio is $25,100 per quality-adjusted life year. Sensitivity analyses indicate that the cost-effectiveness ratio remains acceptable under a wide range of assumptions.

Conclusion

Assuming that the reduced local recurrence rate does lead to a survival advantage, the cost-utility analysis estimates that the improved survival outweighs the impaired quality of life and the increased costs. We conclude that short-term preoperative radiotherapy in patients with rectal cancer undergoing TME is both effective and cost-effective.
A Randomized Controlled Trial of Fluorouracil Plus Leucovorin, Irinotecan, and Oxaliplatin Combinations in Patients With Previously Untreated Metastatic Colorectal Cancer
Authors: Goldberg Richard M. , Sargent Daniel J. , Morton Roscoe F. , Fuchs Charles S. , Ramanathan Ramesh K. , Williamson Stephen K. , Findlay Brian P. , Pitot Henry C. , Alberts Steven R.
Published: December 2003

Purpose

Three agents with differing mechanisms of action are available for treatment of advanced colorectal cancer: fluorouracil, irinotecan, and oxaliplatin. In this study, we compared the activity and toxicity of three different two-drug combinations in patients with metastatic colorectal cancer who had not been treated previously for advanced disease.

Patients and Methods

Patients were concurrently randomly assigned to receive irinotecan and bolus fluorouracil plus leucovorin (IFL, control combination), oxaliplatin and infused fluorouracil plus leucovorin (FOLFOX), or irinotecan and oxaliplatin (IROX). The primary end point was time to progression, with secondary end points of response rate, survival time, and toxicity.

Results

A total of 795 patients were randomly assigned between May 1999 and April 2001. A median time to progression of 8.7 months, response rate of 45%, and median survival time of 19.5 months were observed for FOLFOX. These results were significantly superior to those observed for IFL for all end points (6.9 months, 31%, and 15.0 months, respectively) or for IROX (6.5 months, 35%, and 17.4 months, respectively) for time to progression and response. The FOLFOX regimen had significantly lower rates of severe nausea, vomiting, diarrhea, febrile neutropenia, and dehydration. Sensory neuropathy and neutropenia were more common with the regimens containing oxaliplatin.

Conclusion

The FOLFOX regimen of oxaliplatin and infused fluorouracil plus leucovorin was active and comparatively safe. It should be considered as a standard therapy for patients with advanced colorectal cancer.
Dehydroepiandrosterone Metabolism by 3β-Hydroxysteroid Dehydrogenase/Δ5-Δ4 Isomerase in Adult Zebra Finch Brain: Sex Difference and Rapid Effect of Stress
Authors: Soma Kiran K. , Alday Noel A. , Hau Michaela , Schlinger Barney A.
Published: December 2003

Dehydroepiandrosterone (DHEA) is a precursor to sex steroids such as androstenedione (AE), testosterone (T), and estrogens. DHEA has potent effects on brain and behavior, although the mechanisms remain unclear. One possible mechanism of action is that DHEA is converted within the brain to sex steroids. 3β-Hydroxysteroid dehydrogenase/Δ5-Δ4 isomerase (3β-HSD) catalyzes the conversion of DHEA to AE. AE can then be converted to T and estrogen within the brain. We test the hypothesis that 3β-HSD is expressed in the adult brain in a region- and sex-specific manner using the zebra finch (Taeniopygia guttata), a songbird with robust sex differences in song behavior and telencephalic song nuclei. In zebra finch brain, DHEA is converted by 3β-HSD to AE and subsequently to estrogens and 5α- and 5β-reduced androgens. 3β-HSD activity is highest in the diencephalon and telencephalon. In animals killed within 2–3 min of disturbance, baseline 3β-HSD activity in portions of the telencephalon is higher in females than males. Acute restraint stress (10 min) decreases 3β-HSD activity in females but not in males, and in stressed animals, telencephalic 3β-HSD activity is greater in males than in females. Thus, the baseline sex difference is rapidly reversed by stress. To our knowledge, this is the first demonstration of 1) brain region differences in DHEA metabolism by 3β-HSD, 2) rapid modulation of 3β-HSD activity, and 3) sex differences in brain 3β-HSD and regulation by stress. Songbirds are good animal models for studying the regulation and functions of DHEA and neurosteroids in the nervous system.
Folliculostellate Cells Determine the Susceptibility of Lactotropes to Estradiol’s Mitogenic Action
Authors: Oomizu Souichi , Chaturvedi Kirti , Sarkar Dipak K.
Published: December 2003

Estradiol is known to increase lactotropic cell proliferation, but estradiol susceptibility varies among human populations and among various strains of rats. We had reported that folliculostellate (FS) cells regulate estradiol’s mitogenic action on lactotropes; therefore, we studied their role in determining the susceptibility to estradiol in a high estradiol-responsive rat strain, Fischer 344 (F344), and in a low-responsive strain, Sprague Dawley (SD). Determination of total S-100-positive FS cells in the pituitary revealed that F344 rats have significantly more FS cells than do SD rats. Estradiol treatment did not change the number of FS cells in both F344 and SD rats. When cotransplanted with F344 pituitaries under the kidney capsule or cocultured with F344-derived lactotropes in vitro, FS cells derived from F344 rats increased estradiol’s mitogenic action. They also increased estradiol’s mitogenic action on SD-derived lactotropes in primary cultures. However, SD-derived FS cells failed to increase estrogen’s action on F344- or SD-derived lactotropes. The levels of basic fibroblast growth factor production and secretion by TGF-β3 and estradiol were much higher in F344-derived FS cells than in SD-derived FS cells. However, the lactotropes’ growth response to basic fibroblast growth factor was similar in both strains. These data suggest that cell-cell interaction between FS cells and lactotropes regulates estradiol’s mitogenic action on lactotropes and also determines lactotrope susceptibility to the steroid.
Minireview: Sex Differences in Adult and Developing Brains: Compensation, Compensation, Compensation
Authors: De Vries Geert J.
Published: December 2003

Despite decades of research, we do not know the functional significance of most sex differences in the brain. We are heavily invested in the idea that sex differences in brain structure cause sex differences in behavior. We rarely consider the possibility that sex differences in brain structure may also prevent sex differences in overt functions and behavior, by compensating for sex differences in physiological conditions, e.g. gonadal hormone levels that may generate undesirable sex differences if left unchecked. Such a dual function for sex differences is unlikely to be restricted to adult brains. This review will entertain the possibility that transient sex differences in gene expression in developing brains may cause permanent differences in brain structure but prevent them as well, by compensating for potentially differentiating effects of sex differences in gonadal hormone levels and sex chromosomal gene expression. Consistent application of this dual-function hypothesis will make the search for the functional significance of sex differences more productive.
Assessment of the Role of Activator Protein-1 on Transcription of the Mouse Steroidogenic Acute Regulatory Protein Gene
Authors: Manna Pulak R. , Eubank Darrell W. , Stocco Douglas M.
Published: December 2003

cAMP-dependent mechanisms regulate the steroidogenic acute regulatory (StAR) protein even though its promoter lacks a consensus cAMP response-element (CRE, TGACGTCA). Transcriptional regulation of the StAR gene has been demonstrated to involve combinations of DNA sequences that provide recognition motifs for sequence-specific transcription factors. We recently identified and characterized three canonical 5′-CRE half-sites within the cAMP-responsive region (−151/−1 bp) of the mouse StAR gene. Among these CRE elements, the CRE2 half-site is analogous (TGACTGA) to an activator protein-1 (AP-1) sequence [TGA(C/G)TCA]; therefore, the role of the AP-1 transcription factor was explored in StAR gene transcription. Mutation in the AP-1 element demonstrated an approximately 50% decrease in StAR reporter activity. Using EMSA, oligonucleotide probes containing an AP-1 binding site were found to specifically bind to nuclear proteins obtained from mouse MA-10 Leydig and Y-1 adrenocortical tumor cells. The integrity of the sequence-specific AP-1 element in StAR gene transcription was assessed using the AP-1 family members, Fos (c-Fos, Fra-1, Fra-2, and Fos B) and Jun (c-Jun, Jun B, and Jun D), which demonstrated the involvement of Fos and Jun in StAR gene transcription to varying degrees. Disruption of the AP-1 binding site reversed the transcriptional responses seen with Fos and Jun. EMSA studies utilizing antibodies specific to Fos and Jun demonstrated the involvement of several AP-1 family proteins. Functional assessment of Fos and Jun was further demonstrated by transfecting antisense c-Fos, Fra-1, and dominant negative forms of Fos (A-Fos) and c-Jun (TAM-67) into MA-10 cells, which significantly (P < 0.01) repressed transcription of the StAR gene. Mutation of the AP-1 site in combination with mutations in other cis-elements resulted in a further decrease of StAR promoter activity, demonstrating a functional cooperation between these factors. Mammalian two-hybrid assays revealed high-affinity protein-protein interactions between c-Fos and c-Jun with steroidogenic factor 1, GATA-4, and CCAAT/enhancer binding protein-β. These findings demonstrate that Fos and Jun can bind to the TGACTGA element in the StAR promoter and provide novel insights into the mechanisms regulating StAR gene transcription.
Urban Renewal in the Nucleus: Is Protein Turnover by Proteasomes Absolutely Required for Nuclear Receptor-Regulated Transcription?
Authors: Nawaz Zafar , O’Malley Bert W.
Published: December 2003

The importance of the ubiquitin proteasome pathway in higher eukaryotes has been well established in cell cycle regulation, signal transduction, and cell differentiation, but has only recently been linked to nuclear hormone receptor-regulated gene transcription. Characterization of a number of ubiquitin proteasome pathway enzymes as coactivators and observations that several nuclear receptors are ubiquitinated and degraded in the course of their nuclear activities provide evidence that ubiquitin proteasome-mediated protein degradation plays an integral role in eukaryotic transcription. In addition to receptors, studies have revealed that coactivators are ubiquitinated and degraded via the proteasome. The notion that the ubiquitin proteasome pathway is involved in gene transcription is further strengthened by the fact that ubiquitin proteasome pathway enzymes are recruited to the promoters of target genes and that proteasome-dependent degradation of nuclear receptors is required for efficient transcriptional activity. These findings suggest that protein degradation is coupled with nuclear receptor coactivation activity. It is possible that the ubiquitin proteasome pathway modulates transcription by promoting remodeling and turnover of the nuclear receptor-transcription complex. In this review, we discus the possible role of the ubiquitin proteasome pathway in nuclear hormone receptor-regulated gene transcription.
Caspases function in autophagic programmed cell death inDrosophila
Authors: Martin Damali N. , Baehrecke Eric H.
Published: December 2003

Self-digestion of cytoplasmic components is the hallmark of autophagic programmed cell death. This auto-degradation appears to be distinct from what occurs in apoptotic cells that are engulfed and digested by phagocytes. Although much is known about apoptosis, far less is known about the mechanisms that regulate autophagic cell death. Here we show that autophagic cell death is regulated by steroid activation of caspases in Drosophila salivary glands. Salivary glands exhibit some morphological changes that are similar to apoptotic cells, including fragmentation of the cytoplasm, but do not appear to use phagocytes in their degradation. Changes in the levels and localization of filamentous Actin, α-Tubulin, α-Spectrin and nuclear Lamins precede salivary gland destruction, and coincide with increased levels of active Caspase 3 and a cleaved form of nuclear Lamin. Mutations in the steroid-regulated genes βFTZ-F1, E93, BR-C and E74Athat prevent salivary gland cell death possess altered levels and localization of filamentous Actin, α-Tubulin, α-Spectrin, nuclear Lamins and active Caspase 3. Inhibition of caspases, by expression of either the caspase inhibitor p35 or a dominant-negative form of the initiator caspase Dronc, is sufficient to inhibit salivary gland cell death, and prevent changes in nuclear Lamins and α-Tubulin, but not to prevent the reorganization of filamentous Actin. These studies suggest that aspects of the cytoskeleton may be required for changes in dying salivary glands. Furthermore, caspases are not only used during apoptosis, but also function in the regulation of autophagic cell death.
Tcf3: a transcriptional regulator of axis induction in the early embryo
Authors: Merrill Bradley J. , Pasolli H. Amalia , Polak Lisa , Rendl Michael , García-García Maria J. , Anderson Kathryn V. , Fuchs Elaine
Published: December 2003

The roles of Lef/Tcf proteins in determining cell fate characteristics have been described in many contexts during vertebrate embryogenesis, organ and tissue homeostasis, and cancer formation. Although much of the accumulated work on these proteins involves their ability to transactivate target genes when stimulated by β-catenin, Lef/Tcf proteins can repress target genes in the absence of stabilized β-catenin. By ablating Tcf3 function, we have uncovered an important requirement for a repressor function of Lef/Tcf proteins during early mouse development. Tcf3-/- embryos proceed through gastrulation to form mesoderm, but they develop expanded and often duplicated axial mesoderm structures, including nodes and notochords. These duplications are preceded by ectopic expression of Foxa2, an axial mesoderm gene involved in node specification, with a concomitant reduction in Lefty2, a marker for lateral mesoderm. By contrast,expression of a β-catenin-dependent, Lef/Tcf reporter (TOPGal), is not ectopically activated but is faithfully maintained in the primitive streak. Taken together, these data reveal a unique requirement for Tcf3 repressor function in restricting induction of the anterior-posterior axis.
Multiple roles ofHoxa11andHoxd11in the formation of the mammalian forelimb zeugopod
Authors: Boulet Anne M. , Capecchi Mario R.
Published: December 2003

Mutations in the 5′ or posterior murine Hox genes (paralogous groups 9-13) markedly affect the formation of the stylopod, zeugopod and autopod of both forelimbs and hindlimbs. Targeted disruption of Hoxa11 and Hoxd11 or Hoxa10, Hoxc10 and Hoxd10 result in gross mispatterning of the radius and ulna or the femur, respectively. Similarly, in mice with disruptions of both Hoxa13 and Hoxd13, development of the forelimb and hindlimb autopod is severely curtailed. Although these examples clearly illustrate the major roles played by the posterior Hox genes,little is known regarding the stage or stages at which Hox transcription factors intersect with the limb development program to ensure proper patterning of the principle elements of the limb. Moreover, the cellular and/or molecular bases for the developmental defects observed in these mutant mice have not been described. In this study, we show that malformation of the forelimb zeugopod in Hoxa11/Hoxd11 double mutants is a consequence of interruption at multiple steps during the formation of the radius and ulna. In particular, reductions in the levels of Fgf8 and Fgf10expression may be related to the observed delay in forelimb bud outgrowth that, in turn, leads to the formation of smaller mesenchymal condensations. However, the most significant defect appears to be the failure to form normal growth plates at the proximal and distal ends of the zeugopod bones. As a consequence, growth and maturation of these bones is highly disorganized,resulting in the creation of amorphous bony elements, rather than a normal radius and ulna.
Differential response of p53 target genes to p73 overexpression in SH-SY5Y neuroblastoma cell line
Authors: Goldschneider David , Blanc Etienne , Raguénez Gilda , Barrois Michel , Legrand Agnès , Le Roux Gwenaëlle , Haddada Hedi , Bénard Jean , Douc-Rasy Sétha
Published: December 2003

p73, the first p53 gene homologue, encodes an array of p73 proteins including p73α full-length (TAp73α) and amino-truncated isoforms (ΔNp73α), two proteins with opposite biological functions. TAp73α can induce tumor suppressive properties, while ΔNp73α antagonizes p53 as well as TAp73 in a dominant-negative manner. In human malignant neuroblasts, p53 protein is wild-type but known to be excluded from the nucleus, therefore disabling its function as a tumor suppressor. The present study investigates whether there is a functional link between p73 isoforms and p53 in neuroblastoma. Experiments were performed on two neuroblastoma cell lines differing in their p53 status, e.g. wild-type p53 SH-5Y5Y cells and mutated p53 IGR-N-91 cells. Data indicate that (i) both TA- and ΔN-p73α enhance p53 protein level in SH-SY5Y cells, whereas level remains unchanged in IGR-N-91 cells; (ii) only in SH-SY5Y cells does forced TAp73α overexpression markedly induce nuclear accumulation of p53 protein; (iii) p21 protein expression is increased in both cell lines infected with TAp73, suggesting that, in IGR-N-91 cells, p21 is induced by p73 through a p53-independent pathway; (iv) in the SHSY5Y cell line, Btg2 expression is strongly enhanced in cells overexpressing TA, and to a lesser extent in cells overexpressing ΔN. Taken together our results suggest that TAp73 may restore p53 function in NB with wild-type nonfunctional p53, but not in NB with mutated p53.
Actin cytoskeleton remodelling via local inhibition of contractility at discrete microdomains
Authors: Burgstaller Gerald , Gimona Mario
Published: December 2003

Activation of conventional protein kinase C by phorbol ester triggers the Src-dependent remodelling of the actin cytoskeleton and the formation of podosomes in vascular smooth muscle cells. Rearrangement of actin cytoskeleton in response to phorbol-12,13-dibutyrate is characterised by the simultaneous disassembly of peripheral actin stress fibres and focal adhesions, focal de novo actin polymerisation and actomyosin contraction in the cell center, indicating a spatially and temporally segregated, differential modulation of actin-cytoskeleton stability and turnover. Taking advantage of the prominent actin cytoskeleton in A7r5 cells we show here, that the molecular basis for the local inhibition of contractility is the specific recruitment of p190RhoGAP to specialised microdomains at the focal adhesion/stress fibre interface, which are constitutively enriched in cortactin. The microdomains contain structurally altered actin filaments inaccessible to phalloidin. However, the filaments remain decorated with high molecular weight tropomyosins. Clustering of cortactin during podosome formation causes the rapid, local dispersion of myosin and tropomyosin, and interferes with the F-actin binding of h1calponin, consistent with a RhoGAP-mediated reduction of contractility. Phorbol ester-induced podosome formation is efficiently blocked by expression of constitutively active Dia1, which leads to the dispersion of cortactin. The results provide direct evidence for the spatially restricted inhibition of contractility via the recruitment and accumulation of cortactin and p190RhoGAP.
Analysis of the mechanism by which calcium negatively regulates the tyrosine phosphorylation cascade associated with sperm capacitation
Authors: Baker Mark A. , Hetherington Louise , Ecroyd Heath , Roman Shaun D. , Aitken R. John
Published: December 2003

The capacitation of mammalian spermatozoa involves the activation of a cAMP-mediated signal transduction pathway that drives tyrosine phosphorylation via mechanisms that are unique to this cell type. Controversy surrounds the impact of extracellular calcium on this process, with positive and negative effects being recorded in independent publications. We clearly demonstrate that the presence of calcium in the external medium decreases tyrosine phosphorylation in both human and mouse spermatozoa. Under these conditions, a rise in intracellular pH was recorded, however, this event was not responsible for the observed changes in phosphotyrosine expression. Rather, the impact of calcium on tyrosine phosphorylation in these cells was associated with an unexpected change in the intracellular availability of ATP. Thus, the ATP content of both human and mouse spermatozoa fell significantly when these cells were incubated in the presence of external calcium. Furthermore, the removal of glucose, or addition of 2-deoxyglucose, decreased ATP levels within human spermatozoon populations and induced a corresponding decline in phosphotyrosine expression. In contrast, the mitochondrial inhibitor rotenone had no effect on either ATP levels or tyrosine phosphorylation. Addition of the affinity-labeling probe 8-N3 ATP confirmed our prediction that spermatozoa have many calcium-dependent ATPases. Moreover, addition of the ATPase inhibitor thapsigargin, increased intracellular calcium levels, decreased ATP and suppressed tyrosine phosphorylation. Based on these findings, the present study indicates that extracellular calcium suppresses tyrosine phosphorylation by decreasing the availability of intracellular ATP, and not by activating tyrosine phosphatases or inhibiting tyrosine kinases as has been previously suggested.
Rac2D57N, a dominant inhibitory Rac2 mutant that inhibits p38 kinase signaling and prevents surface ruffling in bone-marrow-derived macrophages
Authors: Abell Amy N. , DeCathelineau Aimee M. , Weed Scott A. , Ambruso Daniel R. , Riches David W. , Johnson Gary L.
Published: December 2003

Rac2 is a Rho GTPase that is expressed in cells of hematopoietic origin, including neutrophils and macrophages. We recently described an immunodeficient patient with severe, recurrent bacterial infections that had a point mutation in one allele of the Rac2 gene, resulting in the substitution of aspartate 57 with asparagine. To ascertain further the effects of Rac2D57N in leukocytes, Rac2D57N was expressed in primary murine bone-marrow-derived macrophages (cells that we show express approximately equal amounts of Rac1 and Rac2). Rac2D57N expression in macrophages inhibited membrane ruffling. Rac2D57N expression inhibited the formation of macropinosomes, demonstrating a functional effect of the loss of surface membrane dynamics. Surprisingly, Rac2D57N induced an elongated, spread morphology but did not affect microtubule networks. Rac2D57N also inhibited lipopolysaccharide-stimulated p38 kinase activation. Examination of guanine nucleotide binding to recombinant Rac2D57N revealed reduced dissociation of GDP and association of GTP. Coimmunoprecipitation studies of Rac2D57N with RhoGDIα and Tiam1 demonstrated increased binding of Rac2D57N to these upstream regulators of Rac signaling relative to the wild type. Enhanced binding of Rac2D57N to its upstream regulators would inhibit Rac-dependent effects on actin cytoskeletal dynamics and p38 kinase signaling.
Kinesin dependent, rapid, bi-directional transport of ER sub-compartment in dendrites of hippocampal neurons
Authors: Bannai Hiroko , Inoue Takafumi , Nakayama Tomohiro , Hattori Mitsuharu , Mikoshiba Katsuhiko
Published: December 2003

Although spatially restricted Ca2+ release from the endoplasmic reticulum (ER) through intracellular Ca2+ channels plays important roles in various neuronal activities, the accurate distribution and dynamics of ER in the dendrite of living neurons still remain unknown. To elucidate these, we expressed fluorescent protein-tagged ER proteins in cultured mouse hippocampal neurons, and monitored their movements using time-lapse microscopy. We report here that a sub-compartment of ER forms in relatively large vesicles that are capable, similarly to the reticular ER, of taking up and releasing Ca2+. The vesicular sub-compartment of ER moved rapidly along the dendrites in both anterograde and retrograde directions at a velocity of 0.2-0.3 μm/second. Depletion of microtubules, overexpression of dominant-negative kinesin and kinesin depletion by antisense DNA reduced the number and velocity of the moving vesicles, suggesting that kinesin may drive the transport of the vesicular sub-compartment of ER along microtubules in the dendrite. Rapid transport of the Ca2+-releasable sub-compartment of ER might contribute to rapid supply of fresh ER proteins to the distal part of the dendrite, or to the spatial regulation of intracellular Ca2+ signaling.
A role for the cytoskeleton in prolactin-dependent mammary epithelial cell differentiation
Authors: Zoubiane Ghada S. , Valentijn Anthony , Lowe Emma T. , Akhtar Nasreen , Bagley Steve , Gilmore Andrew P. , Streuli Charles H.
Published: December 2003

The function of exocrine glands depends on signals within the extracellular environment. In the mammary gland, integrin-mediated adhesion to the extracellular matrix protein laminin co-operates with soluble factors such as prolactin to regulate tissue-specific gene expression. The mechanism of matrix and prolactin crosstalk and the activation of downstream signals are not fully understood. Because integrins organize the cytoskeleton, we analysed the contribution of the cytoskeleton to prolactin receptor activation and the resultant stimulation of milk protein gene expression. We show that the proximal signalling events initiated by prolactin (i.e. tyrosine phosphorylation of receptor and the associated kinase Jak2) do not depend on an intact actin cytoskeleton. However, actin networks and microtubules are both necessary for continued mammary cell differentiation, because cytoskeletal integrity is required to transduce the signals between prolactin receptor and Stat5, a transcription factor necessary for milk protein gene transcription. The two different cytoskeletal scaffolds regulate prolactin signalling through separate mechanisms that are specific to cellular differentiation but do not affect the general profile of protein synthesis.
Ontogeny, immunolocalisation, distribution and function of SR-BI in the human intestine
Authors: Levy Emile , Ménard Daniel , Suc Isabelle , Delvin Edgard , Marcil Valérie , Brissette Louise , Thibault Louise , Bendayan Moise
Published: December 2003

Studies employing human fetal intestine have yielded remarkable information on the role of polarized enterocytes in fat absorption. In this report, we investigated the intestinal expression, spatiotemporal distributions, ontogeny and function of the scavenger receptor, Class B, Type I (SR-BI) that plays a crucial role in cholesterol homeostasis. SR-BI was detected as early as week 14 of gestation in all gut segments and was almost entirely confined to the absorptive epithelial cells. By using immunofluorescence staining, the distribution of SR-BI rarely appeared as a gradient, increasing from the developing crypt to the tip of the villus. Western blot showed high levels of immunodetectable SR-BI in the duodenum, which progressively decreased toward the distal colon. The high-resolution immunogold technique revealed labelling mainly over microvilli of the enterocyte. SR-BI was not associated with caveolin-1 and was not detectable in caveolae. In order to define the role of SR-BI in intestinal cholesterol absorption, Caco-2 cells were transfected with a constitutive expression vector (pZeoSV) containing human SR-BI cDNA inserted in an antisense orientation. As noted by immunoblotting and Protein A-gold techniques, stable transformants contained 40, 60 and 80% the SR-BI level of control Caco-2 cells and exhibited a proportional drop in free cholesterol uptake without altering the capture of phospholipids or cholesteryl ester. Confirmation of these data was obtained in intestinal organ culture where SR-BI antibodies lowered cholesterol uptake. These observations suggest that the human intestine possesses a developmental and regional SR-BI pattern of distribution, and extends our knowledge in SR-BI-mediated cholesterol transport.
Activity of recycling Golgi mannosyltransferases in the yeast endoplasmic reticulum
Authors: Karhinen Leena , Makarow Marja
Published: December 2003

In yeast primary N- and O-glycans are attached to proteins in the endoplasmic reticulum (ER), and they are elongated in the Golgi. Thus, glycan extension by Golgi enzymes has been taken as evidence for arrival of a protein in the Golgi. Two α1,6-mannosyltransferase activity-containing multiprotein complexes have been reported to recycle between the Golgi and the ER, but since resident ER proteins are not Golgi-modified, Golgi enzymes were not thought to function in the ER. Here we show that when protein exit from the ER was blocked in COPII-defective yeast mutants, the N-glycans of vacuolar carboxypeptidase Y and a set of unidentified glycoproteins were decorated with an α1,6-mannose residue, normally added in the Golgi by Och1p. Immunofluorescent staining demonstrated that Och1p accumulated in the ER under these conditions. Concomitantly, primary O-glycans of a secretory protein were extended, apparently by the medial Golgi transferase Mnt1p. Similar O-glycan extension occurred in wild-type cells when an HDEL-tagged protein was allowed to encounter glycosyltransferases in the Golgi during recycling between ER and Golgi. Golgi-specific glycosylation in the ER was reduced when Golgi-to-ER traffic was blocked, confirming that glycan extension in the ER was mainly due to recycling, rather than newly synthesized transferases.