bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical Variables Associated with Mortality in Out‐of‐hospital Patients with Hemodynamically Significant Bradycardia
Authors: Schwartz Brian , Vermeulen Marian J. , Idestrup Chris , Datta Partha
Published: June 2004

Objectives: To estimate mortality rates and identify clinical variables associated with mortality among patients with hemodynamically unstable bradycardia in an urban emergency medical services (EMS) system. Methods:This was a retrospective study conducted in a large, urban EMS system. Adult non–cardiac arrest patients transported by advanced life support paramedics from March 1996 to February 1997 with a heart rate ≤60 beats/min and systolic blood pressure ≤90 mm Hg were included. Transcutaneous pacing was not available. Patients under age 18 years, pregnant, or presenting with vital signs absent were excluded from the study population. Multivariate analysis of the association of patient characteristics with 30‐day mortality was conducted by using a Cox proportional hazards model. Results: Of the 247 patients studied, 133 (53.9%) received a fluid bolus, 37 (15.0%) were treated with atropine, and 17 (6.9%) received dopamine. Fifty‐one (20.7%) died in the 19‐month follow‐up period (15.6 per 100 person‐years); 10.5% died on the same day, 15.8% within 30 days, and 17.8% within one year. Variables associated with 30‐day mortality included wide QRS complex (adjusted risk ratio [RR] 2.6 [95% confidence interval (95% CI) = 1.3 to 5.2]), use of heart rate‐lowering calcium channel blockers (adjusted RR 2.1 [95% CI = 1.0 to 4.7]), and paramedic assessment of lack of patient improvement over the course of the call (adjusted RR 0.2 [95% CI = 0.1 to 0.6]). Conclusions: Out‐of‐hospital patients with hemodynamically unstable bradycardia have a high mortality rate. A wide QRS complex and use of heart rate‐lowering calcium channel blockers were associated with 30‐day mortality.
Phase I Trial of the Proteasome Inhibitor Bortezomib in Patients With Advanced Solid Tumors With Observations in Androgen-Independent Prostate Cancer
Authors: Papandreou Christos N. , Daliani Danai D. , Nix Darrell , Yang Hong , Madden Timothy , Wang Xuemei , Pien Christine S. , Millikan Randall E. , Tu Shi-Ming , Pagliaro Lance , Kim Jeri , Adams Julian , Elliott Peter , Esseltine Dixie , Petrusich Alexandria , Dieringer Pauline , Perez Cherie , Logothetis Christopher J.
Published: May 2004

Purpose

To determine the dose-limiting toxicity and maximum-tolerated dose of the proteasome inhibitor bortezomib administered intravenously weekly for 4 every 5 weeks; to determine the bortezomib pharmacokinetics and pharmacodynamics using plasma levels and an assay for 20S proteasome inhibition (PI) in whole blood; to correlate toxicity with bortezomib dose and degree of 20S PI; and to conduct a preliminary determination of the antitumor activity of bortezomib in patients with androgen independent prostate cancer (AIPCa).

Patients and Methods

Fifty-three patients (48 with AIPCa) received 128 cycles of bortezomib in doses ranging from 0.13 to 2.0 mg/m2/dose, utilizing a careful escalation scheme with a continuous reassessment method. Pharmacokinetic and pharmacodynamic studies were performed in 24 patients (at 1.45 to 2.0 mg/m2).

Results

A dose-related 20S PI was seen, with dose-limiting toxicity at 2.0 mg/m2 (diarrhea, hypotension) occurring at an average 1-hour post-dose of ≥ 75% 20S PI. Other side effects were fatigue, hypertension, constipation, nausea, and vomiting. No relationship was seen between body-surface area and bortezomib clearance over the narrow dose range tested. There was evidence of biologic activity (decline in serum prostate-specific antigen and interleukin-6 levels) at ≥ 50% 20S PI. Two patients with AIPCa had prostate-specific antigen response and two patients had partial response in lymph nodes.

Conclusion

The maximum-tolerated dose and recommended phase II dose of bortezomib in this schedule is 1.6 mg/m2. Biologic activity (inhibition of nuclear factor-kappa B-related markers) and antitumor activity is seen in AIPCa at tolerated doses of bortezomib. This agent should be further explored with chemotherapy agents in advanced prostate cancer.
Phase III Trial of Doxorubicin Plus Cisplatin With or Without Paclitaxel Plus Filgrastim in Advanced Endometrial Carcinoma: A Gynecologic Oncology Group Study
Authors: Fleming Gini F. , Brunetto Virginia L. , Cella David , Look Katherine Y. , Reid Gary C. , Munkarah Adnan R. , Kline Richard , Burger Robert A. , Goodman Annekathryn , Burks R. Tucker
Published: May 2004

Purpose

To determine whether the addition of paclitaxel to doxorubicin plus cisplatin improves overall survival (OS) in women with advanced or recurrent endometrial carcinoma. Secondary comparisons included progression-free survival (PFS), response rate (RR), and toxicities.

Patients and Methods

Eligible, consenting patients received doxorubicin 60 mg/m2 and cisplatin 50 mg/m2 (AP), or doxorubicin 45 mg/m2 and cisplatin 50 mg/m2 (day 1), followed by paclitaxel 160 mg/m2 (day 2) with filgrastim support (TAP). The initial doxorubicin dose in the AP arm was reduced to 45 mg/m2 in patients with prior pelvic radiotherapy and those older than 65 years. Both regimens were repeated every 3 weeks to a maximum of seven cycles. Patients completed a neurotoxicity questionnaire before each cycle.

Results

Two hundred seventy-three women (10 ineligible) were registered. Objective response (57% v 34%; P < .01), PFS (median, 8.3 v 5.3 months; P < .01), and OS (median, 15.3 v 12.3 months; P = .037) were improved with TAP. Treatment was hematologically well tolerated, with only 2% of patients receiving AP, and 3% of patients receiving TAP experiencing neutropenic fever. Neurologic toxicity was worse for those receiving TAP, with 12% grade 3, and 27% grade 2 peripheral neuropathy, compared with 1% and 4%, respectively, in those receiving AP. Patient-reported neurotoxicity was significantly higher in the TAP arm following two cycles of therapy.

Conclusion

TAP significantly improves RR, PFS, and OS compared with AP. Evaluation of this regimen in the high-risk adjuvant setting is warranted, but close attention should be paid to the increased risk of peripheral neuropathy.
Four Decades of Continuing Innovation With Fluorouracil: Current and Future Approaches to Fluorouracil Chemoradiation Therapy
Authors: Rich Tyvin A. , Shepard Robert C. , Mosley Stephen T.
Published: May 2004

Purpose

Chemoradiotherapy, the combination of external radiation therapy and concurrent chemotherapy, has been the basis for the oncologic management of many patients since its development in the 1960s. Fluorouracil (FU) chemoradiotherapy has demonstrated success in several organ sites with multiple dosing schedules that now guide the selection of oral analogs of FU to provide new chemoradiotherapy options.

Methods

This article reviews the metabolism and pharmacology of FU and the advantages of administration of FU by continuous infusion or bolus. The potential role and impact of the oral fluorouracil prodrugs UFT, S-1, BOF-A2, and capecitabine as replacements for intravenous administration are discussed. The results of recent chemoradiotherapy studies with FU from 2000 to 2003 are summarized in rectal, head and neck, esophageal, gastric, pancreatic, biliary, anal, and cervical cancers.

Results

Chemoradiotherapy with FU has the potential to widen the therapeutic window by minimizing normal tissue toxicity while maintaining effective tumor toxicity. Overall, FU chemoradiotherapy maximizes local control and, for some tumor sites (such as head and neck, pancreatic, biliary, cervical, esophageal, and gastric cancers), improves survival rates. Moreover, FU chemoradiotherapy results in improved organ preservation with excellent functional outcome in several anatomic sites including head and neck cancer, anal, and rectal cancer, with improved sphincter preservation.

Conclusion

FU chemoradiotherapy continues to play an important role in the management of many cancer sites. During the last four decades, optimal dosing schedules have produced a therapeutic gain. The introduction of oral prodrug analogs will likely further improve the results of FU therapy in several organ systems, such as the rectum, head and neck, and esophagus.
Failure of Higher-Dose Paclitaxel to Improve Outcome in Patients With Metastatic Breast Cancer: Cancer and Leukemia Group B Trial 9342
Authors: Winer Eric P. , Berry Donald A. , Woolf Susan , Duggan David , Kornblith Alice , Harris Lyndsay N. , Michaelson Richard A. , Kirshner Jeffrey A. , Fleming Gini F. , Perry Michael C. , Graham Mark L. , Sharp Stewart A. , Keresztes Roger , Henderson I. Craig , Hudis Clifford , Muss Hyman , Norton Larry
Published: May 2004

Purpose

Cancer and Leukemia Group B Protocol 9342 was initiated to determine the optimal dose of paclitaxel administered as a 3-hour infusion every 3 weeks to women with metastatic breast cancer.

Patients and Methods

Four hundred seventy-four women with metastatic breast cancer who had received one or no prior chemotherapy regimens were randomly assigned to one of three paclitaxel dosing regimens—175 mg/m2, 210 mg/m2, or 250 mg/m2—each administered as a 3-hour infusion every 3 weeks. Women completed self-administered quality of life and symptom assessment questionnaires at baseline and after three cycles of treatment.

Results

No evidence of a significant dose-response relationship was demonstrated over the dose range assessed. Response rates were 23%, 26%, and 21% for the three regimens, respectively. A marginally significant association (P = .04) was seen between dose and time to progression; however, in a multivariate analysis, the difference was even less apparent. No statistically significant difference was seen in survival. Neurotoxicity and hematologic toxicity were more severe on the higher dose arms. There was no significant difference in quality of life on the three arms.

Conclusion

Higher doses of paclitaxel administered as a 3-hour infusion to women with metastatic breast cancer did not improve response rate, survival, or quality of life. There was a slight improvement in time to progression with higher dose therapy, which was offset by greater toxicity. When a 3-hour infusion of paclitaxel is administered every 3 weeks, 175 mg/m2 should be considered the optimal dose.
Cognitive Impairment Associated With Chemotherapy for Cancer: Report of a Workshop
Authors: Tannock Ian F. , Ahles Tim A. , Ganz Patricia A. , van Dam Frits S.
Published: May 2004

Cognitive dysfunction may occur in some patients who receive chemotherapy. We provide a summary of an April 2003 workshop on this topic, that included medical oncologists, radiologists, clinical and experimental psychologists, and patient advocates. Current studies indicate that cognitive deficits are often subtle, although they are observed consistently in a proportion of patients, may be durable, and can be disabling. Deficits have been observed in a range of cognitive functions. Underlying mechanisms are unknown, although preliminary studies suggest there may be genetic predisposition and that cognitive impairment may be accompanied by changes in the brain detectable by neuroimaging. The following priorities were established for future research: (1) large-scale clinical studies that use both a longitudinal design and concurrent evaluation of patients with cancer who do not receive chemotherapy—such studies should address the probability and magnitude of cognitive deficits, factors that predict them, and underlying mechanisms; (2) exploration of discrepancies between subjective reports of cognitive dysfunction and the objective results of cognitive testing; (3) studies of cognitive function in patients receiving treatment for diseases other than breast cancer, and in both men and women, to address the hypothesis that underlying mechanisms relate to changes in serum levels of sex hormones and/or to chemotherapy-induced menopause; (4) development of interventions to alleviate these problems; and (5) development of animal models and the use of imaging techniques to address mechanisms that might cause cognitive impairment associated with chemotherapy.
Ki-67 Staining Is a Strong Predictor of Distant Metastasis and Mortality for Men With Prostate Cancer Treated With Radiotherapy Plus Androgen Deprivation: Radiation Therapy Oncology Group Trial 92–02
Authors: Pollack A. , DeSilvio M. , Khor L.-Y. , Li R. , Al-Saleem T.I. , Hammond M.E. , Venkatesan V. , Lawton C.A. , Roach M. , Shipley W.U. , Hanks G.E. , Sandler H.M.
Published: May 2004

Purpose

The Ki-67 staining index (Ki67-SI) has been associated with prostate cancer patient outcome; however, few studies have involved radiotherapy (RT) -treated patients. The association of Ki67-SI to local failure (LF), biochemical failure (BF), distant metastasis (DM), cause-specific death (CSD) and overall death (OD) was determined in men randomly assigned to short term androgen deprivation (STAD) + RT or long-term androgen deprivation (LTAD) + RT.

Patients and Methods

There were 537 patients (35.5%) on Radiation Therapy Oncology Group (RTOG) 92-02 who had sufficient tissue for Ki67-SI analysis. Median follow-up was 96.3 months. Ki67-SI cut points of 3.5% and 7.1% were previously found to be related to patient outcome and were examined here in a Cox proportional hazards multivariate analysis (MVA). Ki67-SI was also tested as a continuous variable. Covariates were dichotomized in accordance with stratification and randomization criteria.

Results

Median Ki67-SI was 6.5% (range, 0% to 58.2%). There was no difference in the distribution of patients in the Ki-67 analysis cohort (n = 537) and the other patients in RTOG 92-02 (n = 977) by any of the covariates or end points tested. In MVAs, Ki67-SI (continuous) was associated with LF (P = .08), BF (P = .0445), DM (P < .0001), CSD (P < .0001), and OD (P = .0094). When categoric variables were used in MVAs, the 3.5% Ki67-SI cut point was not significant. The 7.1% cut point was related to BF (P = .09), DM (P = .0008), and CSD (P = .017). Ki67-SI was the most significant correlate of DM and CSD. A detailed analysis of the hazard rates for DM in all possible covariate combinations revealed subgroups of patients treated with STAD + RT that did not require LTAD.

Conclusion

Ki67-SI was the most significant determinant of DM and CSD and was also associated with OD. The Ki67-SI should be considered for the stratification of patients in future trials.
Signal Transducer and Activator of Transcription-5 Activation and Breast Cancer Prognosis
Authors: Nevalainen Marja T. , Xie Jianwu , Torhorst Joachim , Bubendorf Lukas , Haas Philippe , Kononen Juha , Sauter Guido , Rui Hallgeir
Published: May 2004

Purpose

Transcription factor signal transducer and activator of transcription-5 (Stat5) promotes breast epithelial cell differentiation. We retrospectively analyzed whether levels of active Stat5 in breast cancer were linked to clinical outcome.

Materials and Methods

Immunohistochemistry was used to detect active, tyrosine-phosphorylated Stat5 in paraffin-embedded breast cancer specimens from three archival tissue microarray materials A, B, and C. Material A included 19 healthy human breast tissues and a progression series of primary lymph node-negative, primary lymph node-positive, and metastatic breast cancer (n = 400). Materials B (n = 785) and C (n = 570) represented two independent arrays of unselected primary breast cancer specimens with clinical follow-up data.

Results

Material A demonstrated that Stat5 activation, but not Stat5 protein expression, was gradually lost during cancer progression, with detectable activation in 100% of healthy breast specimens compared with less than 20% of node-positive breast cancers and metastases. Stat5 activation in tumors of material B was associated with favorable prognosis. This observation was confirmed and extended in material C to include both breast cancer-specific survival and disease-free survival. Stat5 activation remained an independent prognostic marker after adjusting for patient age, tumor size, histological grade, estrogen receptor, progesterone receptor, and Her2/neu status by Cox multivariate analysis (hazard ratio, 2.0; P = .029). Stat5 activation was a particularly favorable marker in the lymph node-negative breast cancer subpopulation (hazard ratio, 7.5; P = .003).

Conclusion

In our study, active Stat5 distinguishes breast cancer patients with favorable prognosis, and may be a useful marker for selection of more individualized treatment, especially in localized disease. These findings require confirmation in a large prospective study.
Histone deacetylase 1 is required to repress Notch target gene expression during zebrafish neurogenesis and to maintain the production of motoneurones in response to hedgehog signalling
Authors: Cunliffe Vincent T.
Published: May 2004

Histone deacetylases (Hdacs) are widely implicated as key components of transcriptional silencing mechanisms. Here, I show that hdac1 is specifically required in the zebrafish embryonic CNS to maintain neurogenesis. In hdac1 mutant embryos, the Notch-responsive E(spl)-related neurogenic gene her6 is ectopically expressed at distinct sites within the developing CNS and proneural gene expression is correspondingly reduced or eliminated. Using an hdac1-specific morpholino, I show that this requirement for hdac1 is epistatic to the requirement for Notch signalling. Consequently, hdac1-deficient embryos exhibit several defects of neuronal specification and patterning, including a dramatic deficit of hedgehog-dependent branchiomotor neurones that is refractory to elevated levels of hedgehog signalling. Thus, in the zebrafish embryo, hdac1 is an essential component of the transcriptional silencing machinery that supports the formation and subsequent differentiation of neuronal precursors.
her3, a zebrafish member of thehairy-E(spl)family, is repressed by Notch signalling
Authors: Hans Stefan , Scheer Nico , Riedl Iris , Weizsäcker Elisabeth v. , Blader Patrick , Campos-Ortega José A.
Published: May 2004

her3 encodes a zebrafish bHLH protein of the Hairy-E(Spl) family. During embryogenesis, the gene is transcribed exclusively in the developing central nervous system, according to a fairly simple pattern that includes territories in the mesencephalon/rhombencephalon and the spinal cord. In all territories, the her3 transcription domain encompasses regions in which neurogenin 1 (neurog1) is not transcribed, suggesting regulatory interactions between the two genes. Indeed, injection of her3 mRNA leads to repression of neurog1 and to a reduction in the number of primary neurones, whereas her3 morpholino oligonucleotides cause ectopic expression of neurog1 in the rhombencephalon. Fusions of Her3 to the transactivation domain of VP16 and to the repression domain of Engrailed show that Her3 is indeed a transcriptional repressor. Dissection of the Her3 protein reveals two possible mechanisms for transcriptional repression: one mediated by the bHLH domain and the C-terminal WRPW tetrapeptide; and the other involving the N-terminal domain and the orange domain. Gel retardation assays suggest that the repression of neurog1 transcription occurs by binding of Her3 to specific DNA sequences in the neurog1 promoter. We have examined interrelationships of her3 with members of the Notch signalling pathway by the Gal4-UAS technique and mRNA injections. The results indicate that Her3 represses neurog1 and, probably as a consequence of the neurog1 repression, deltaA, deltaD and her4. Moreover, Her3 represses its own transcription as well. Surprisingly, and in sharp contrast to other members of the E(spl)gene family, transcription of her3 is repressed rather than activated by Notch signalling.
Rescue of enzyme deficiency in embryonic diaphragm in a mouse model of metabolic myopathy: Pompe disease
Authors: Rucker Mary , Fraites Thomas J. , Porvasnik Stacy L. , Lewis Melissa A. , Zolotukhin Irene , Cloutier Denise A. , Byrne Barry J.
Published: May 2004

Several human genetic diseases that affect striated muscle have been modeled by creating knockout mouse strains. However, many of these are perinatal lethal mutations that result in death from respiratory distress within hours after birth. As the diaphragm muscle does not contract until birth, the sudden increase in diaphragm activity creates permanent injury to the muscle causing it to fail to meet respiratory demands. Therefore, the impact of these mutations remains hidden throughout embryonic development and early death prevents investigators from performing detailed studies of other striated muscle groups past the neonatal stage. Glycogen storage disease type II (GSDII), caused by a deficiency in acid α-glucosidase (GAA), leads to lysosomal accumulation of glycogen in all cell types and abnormal myofibrillogenesis in striated muscle. Contractile function of the diaphragm muscle is severely affected in both infantile-onset and late-onset individuals, with death often resulting from respiratory failure. The knockout mouse model of GSDII survives well into adulthood despite the gradual weakening of all striated muscle groups. Using this model, we investigated the delivery of recombinant adeno-associated virus (rAAV) vectors encoding the human GAA cDNA to the developing embryo. Results indicate specific high-level transduction of diaphragm tissue, leading to activity levels up to 10-fold higher than normal and restoration of normal contractile function. Up to an estimated 50 vector copies per diploid genome were quantified in treated diaphragms. Histological glycogen staining of treated diaphragms revealed prevention of lysosomal glycogen accumulation in almost all fibers when compared with untreated controls. This method could be employed with disease models where specific rescue of the diaphragm would allow for increased survival and thus further investigation into the impact of the gene deletion on other striated muscle groups.
Nemo is an inducible antagonist of Wingless signaling duringDrosophilawing development
Authors: Zeng Yi A. , Verheyen Esther M.
Published: May 2004

The cellular events that govern patterning during animal development must be precisely regulated. This is achieved by extrinsic factors and through the action of both positive and negative feedback loops. Wnt/Wg signals are crucial across species in many developmental patterning events. We report that Drosophila nemo (nmo) acts as an intracellular feedback inhibitor of Wingless (Wg) and that it is a novel Wg target gene. Nemo antagonizes the activity of the Wg signal, as evidenced by the finding that reduction of nmo rescues the phenotypic defects induced by misexpression of various Wg pathway components. In addition, the activation of Wg-dependent gene expression is suppressed in wing discs ectopically expressing nmo and enhanced cell autonomously in nmo mutant clones. We find that nmo itself is a target of Wg signaling in the imaginal wing disc. nmo expression is induced upon high levels of Wg signaling and can be inhibited by interfering with Wg signaling. Finally, we observe alterations in Arm stabilization upon modulation of Nemo. These observations suggest that the patterning mechanism governed by Wg involves a negative feedback circuit in which Wg induces expression of its own antagonist Nemo.
Asymmetric leaf development and blade expansion inArabidopsisare mediated by KANADI and YABBY activities
Authors: Eshed Yuval , Izhaki Anat , Baum Stuart F. , Floyd Sandra K. , Bowman John L.
Published: May 2004

Asymmetric development of plant lateral organs is initiated by a partitioning of organ primordia into distinct domains along their adaxial/abaxial axis. Two primary determinants of abaxial cell fate are members of the KANADI and YABBY gene families. Progressive loss of KANADI activity in loss-of-function mutants results in progressive transformation of abaxial cell types into adaxial ones and a correlated loss of lamina formation. Novel, localized planes of blade expansion occur in some kanadi loss-of-function genotypes and these ectopic lamina outgrowths are YABBY dependent. We propose that the initial asymmetric leaf development is regulated primarily by mutual antagonism between KANADI and PHB-like genes,which is translated into polar YABBY expression. Subsequently, polar YABBY expression contributes both to abaxial cell fate and to abaxial/adaxial juxtaposition-mediated lamina expansion.
A screen for modifiers of RacGAP(84C) gain-of-function in theDrosophilaeye revealed the LIM kinase Cdi/TESK1 as a downstream effector of Rac1 during spermatogenesis
Authors: Raymond Karine , Bergeret Evelyne , Avet-Rochex Amélie , Griffin-Shea Ruth , Fauvarque Marie-Odile
Published: May 2004

In Drosophila, RotundRacGAP/RacGAP(84C) is critical to retinal organisation and spermatogenesis. We show that eye-directed expression of RacGAP(84C) or its GTPase activating protein (GAP) domain induces a dominant rough eye phenotype which we used as a starting point in a gain-of-function screen to identify new partners of RacGAP(84C). Proteins known to function in Ras, Rho and Rac signalling were identified confirming the essential role of RacGAP(84C) in crosstalk between GTPases. Other potential RacGAP(84C) partners identified by the screen are implicated in signal transduction, DNA remodelling, cytoskeletal organisation, membrane trafficking and spermatogenesis. This latter class includes the serine/threonine kinase Center divider (Cdi), which is homologous to the human LIM kinase, Testis specific kinase 1 (TESK1), involved in cytoskeleton control through Cofilin phosphorylation. Eye-directed expression of cdi strongly suppressed the phenotypes induced by either RacGAP(84C) gain-of-function or by the dominant negative form of Rac1, Rac1N17. These results are consistent with Cdi being a specific downstream target of Rac1. We showed that Rac1 and cdi are both expressed in Drosophila testis and that homozygous Rac1 mutants exhibit poor fertility that is further reduced by introducing a cdi loss-of-function mutation in trans. Thus, results from a misexpression screen in the eye led us to a putative novel Rac1-Cdi-Cofilin pathway, regulated by RacGAP(84C), coordinating Drosophila spermatogenesis.
LC3, GABARAP and GATE16 localize to autophagosomal membrane depending on form-II formation
Authors: Kabeya Yukiko , Mizushima Noboru , Yamamoto Akitsugu , Oshitani-Okamoto Satsuki , Ohsumi Yoshinori , Yoshimori Tamotsu
Published: May 2004

Rat LC3, a homologue of yeast Atg8 (Aut7/Apg8), localizes to autophagosomal membranes after post-translational modifications. The C-terminal fragment of LC3 is cleaved immediately following synthesis to yield a cytosolic form called LC3-I. A subpopulation of LC3-I is further converted to an autophagosome-associating form, LC3-II.

Because yeast Atg8 is conjugated with phosphatidylethanolamine (PE) by a ubiquitin-like system, it has been hypothesized that LC3 is modified in a similar manner. Here, we show that [14C]-ethanolamine was preferentially incorporated into LC3-II, suggesting that LC3-II is a PE-conjugated form. LC3-II can be a substrate of mammalian Atg4B, a homologue of yeast Atg8-PE deconjugase, supporting the idea that LC3-II is LC3-PE. Moreover, two other mammalian homologues of yeast Atg8, γ-aminobutyric-acid-type-A-receptor-associated protein (GABARAP) and Golgi-associated ATPase enhancer of 16 kDa (GATE16) also generate form II, which are recovered in membrane fractions. Generation of the form II correlates with autophagosome association of GABARAP and GATE16. These results suggest that all mammalian Atg8 homologues receive a common modification to associate with autophagosomal membrane as the form II.
Requirement of ryanodine receptors for pacemaker Ca2+ activity in ICC and HEK293 cells
Authors: Aoyama Masahiro , Yamada Aki , Wang Jing , Ohya Susumu , Furuzono Shinji , Goto Takayo , Hotta Shingo , Ito Yasushi , Matsubara Tatsuaki , Shimokata Kaoru , Chen S. R. Wayne , Imaizumi Yuji , Nakayama Shinsuke
Published: May 2004

Intracellular Ca2+ ([Ca2+]i) oscillations seen in interstitial cells of Cajal (ICCs) are considered to be the primary pacemaker activity in the gut. Here, we show evidence that periodic Ca2+ release from intracellular Ca2+ stores produces [Ca2+]i oscillations in ICCs, using cell cluster preparations isolated from mouse ileum. The pacemaker [Ca2+]i oscillations in ICCs are preserved in the presence of dihydropyridine Ca2+ antagonists, which suppress Ca2+ activity in smooth muscle cells. However, applications of drugs affecting either ryanodine receptors or inositol 1,4,5-trisphosphate receptors terminated [Ca2+]i oscillations at relatively low concentrations. RT-PCR analyses revealed a predominant expression of type 3 RyR (RyR3) in isolated c-Kit-immunopositive cells (ICCs). Furthermore, we demonstrate that pacemaker-like global [Ca2+]i oscillation activity is endowed by introducing RyR3 into HEK293 cells, which originally express only IP3Rs. The reconstituted [Ca2+]i oscillations in HEK293 cells possess essentially the same pharmacological characteristics as seen in ICCs. The results support the functional role of RyR3 in ICCs.
Cytoskeletal restraints regulate homotypic ALCAM-mediated adhesion through PKCα independently of Rho-like GTPases
Authors: Zimmerman Aukje W. , Nelissen Judith M. D. T. , van Emst-de Vries Sjenet E. , Willems Peter H. G. M. , de Lange Frank , Collard John G. , van Leeuwen Frank N. , Figdor Carl G.
Published: May 2004

The activated leukocyte cell adhesion molecule (ALCAM) is dynamically regulated by the actin cytoskeleton. In this study we explored the molecular mechanisms and signaling pathways underlying the cytoskeletal restraints of this homotypic adhesion molecule. We observed that ALCAM-mediated adhesion induced by cytoskeleton-disrupting agents is accompanied by activation of the small GTPases RhoA, Rac1 and Cdc42. Interestingly, unlike adhesion mediated by integrins or cadherins, ALCAM-mediated adhesion appears to be independent of Rho-like GTPase activity. By contrast, we demonstrated that protein kinase C (PKC) plays a major role in ALCAM-mediated adhesion. PKC inhibition by chelerythrine chloride and myristoylated PKC pseudosubstrate, as well as PKC downregulation by PMA strongly reduce cytoskeleton-dependent ALCAM-mediated adhesion. Since serine and threonine residues are dispensable for ALCAM-mediated adhesion and ALCAM is not phosphorylated, we can rule out that ALCAM itself is a direct PKC substrate. We conclude that PKCα plays a dominant role in cytoskeleton-dependent avidity modulation of ALCAM.
Snail and E47 repressors ofE-cadherininduce distinct invasive and angiogenic properties in vivo
Authors: Peinado Hector , Marin Faustino , Cubillo Eva , Stark Hans-Juergen , Fusenig Norbert , Nieto M. Angela , Cano Amparo
Published: May 2004

The transcription factors Snail and E47 are direct repressors of E-cadherin, with both inducing a full epithelial-mesenchymal transition and invasive behaviour in vitro when expressed in the prototypic epithelial MDCK cell line. The role of these repressors in the invasive process and in other tumorigenic properties is, nevertheless, still poorly understood. However, organotypic cultures and in vivo transplantation assays indicate that cells expressing MDCK-Snail and MDCK-E47 exhibit significant differences. MDCK-Snail cells have a higher infiltrative potential than MDCK-E47 cells. Interestingly, both cell types induce angiogenesis of the host stromal tissue in transplantation assays, but this property is greatly enhanced in transplants of MDCK-E47 cells. Xenografted tumours induced in nude mice also show signs of strong angiogenic potential, again markedly increased in tumours induced by MDCK-E47 which exhibit a higher vessel density and proliferation rate than those induced by MDCK-Snail cells. These results suggest differential roles for Snail and E47 E-cadherin repressors in tumour progression where Snail is implicated in promoting the initial invasion and E47 plays an active role in tumour cell growth by promoting angiogenesis.
Annexins – unique membrane binding proteins with diverse functions
Authors: Rescher Ursula , Gerke Volker
Published: May 2004

Annexins are a well-known multigene family of Ca2+-regulated phospholipid-binding and membrane-binding proteins. Recent work employing annexin-knockdown or - knockout models has provided new insights into the biological functions of different annexin proteins. Transient annexin depletion by RNA interference and the expression of dominant-negative mutant proteins has revealed roles for the proteins in membrane processes ranging from the control of membrane structure to certain membrane transport phenomena. Although such functions correlate well with the ability of annexins to interact with cellular membranes in a reversible and regulated manner, some activities are membrane independent, probably because annexins can also engage in specific protein-protein interactions. Among other things, this is evident in annexin A1- and A2-knockout mice, which show impaired regulation of neutrophil extravasation and defects in plasmin generation, respectively.
A Cholinergic Synaptically Triggered Event Participates in the Generation of Persistent Activity Necessary for Eye Fixation
Authors: de Dios Navarro-López Juan , Alvarado Juan Carlos , Márquez-Ruiz Javier , Escudero Miguel , Delgado-García José M. , Yajeya Javier
Published: June 2004

An exciting topic regarding integrative properties of the nervous system is how transient motor commands or brief sensory stimuli are able to evoke persistent neuronal changes, mainly as a sustained, tonic action potential firing. A persisting firing seems to be necessary for postural maintenance after a previous movement. We have studiedin vitroandin vivothe generation of the persistent neuronal activity responsible for eye fixation after spontaneous eye movements. Rat sagittal brainstem slices were used for the intracellular recording of prepositus hypoglossi (PH) neurons and their synaptic activation from nearby paramedian pontine reticular formation (PPRF) neurons. Single electrical pulses applied to the PPRF showed a monosynaptic glutamatergic projection on PH neurons, acting on AMPA-kainate receptors. Train stimulation of the PPRF area evoked a sustained depolarization of PH neurons exceeding (by hundreds of milliseconds) stimulus duration. Both duration and amplitude of this sustained depolarization were linearly related to train frequency. The train-evoked sustained depolarization was the result of interaction between glutamatergic excitatory burst neurons and cholinergic mesopontine reticular fibers projecting onto PH neurons, because it was prevented by slice superfusion with cholinergic antagonists and mimicked by cholinergic agonists. As expected, microinjections of cholinergic antagonists in the PH nucleus of alert behaving cats evoked a gaze-holding deficit consisting of a re-centering drift of the eye after each saccade. These findings suggest that a slow, cholinergic, synaptically triggered event participates in the generation of persistent activity characteristic of PH neurons carrying eye position signals.
Functional Integration of Embryonic Stem Cell-Derived NeuronsIn Vivo
Authors: Wernig Marius , Benninger Felix , Schmandt Tanja , Rade Monika , Tucker Kerry L. , Büssow Heinrich , Beck Heinz , Brüstle Oliver
Published: June 2004

Pluripotency and the potential for continuous self-renewal make embryonic stem (ES) cells an attractive donor source for neuronal cell replacement. Despite recent encouraging results in this field, little is known about the functional integration of transplanted ES cell-derived neurons on the single-cell level. To address this issue, ES cell-derived neural precursors exhibiting neuron-specific enhanced green fluorescent protein (EGFP) expression were introduced into the developing brain. Donor cells implanted into the cerebral ventricles of embryonic rats migrated as single cells into a variety of brain regions, where they acquired complex morphologies and adopted excitatory and inhibitory neurotransmitter phenotypes. Synaptic integration was suggested by the expression of PSD-95 (postsynaptic density-95) on donor cell dendrites, which in turn were approached by multiple synaptophysin-positive host axon terminals. Ultrastructural and electrophysiological data confirmed the formation of synapses between host and donor cells. Ten to 21 d after birth, all EGFP-positive donor cells examined displayed active membrane properties and received glutamatergic and GABAergic synaptic input from host neurons. These data demonstrate that, at the single-cell level, grafted ES cell-derived neurons undergo morphological and functional integration into the host brain circuitry. Antibodies to the region-specific transcription factors Bf1, Dlx, En1, and Pax6 were used to explore whether functional donor cell integration depends on the acquisition of a regional phenotype. Our data show that incorporated neurons frequently exhibit a lacking or ectopic expression of these transcription factors. Thus, the lack of an appropriate regional “code” does not preclude morphological and synaptic integration of ES cell-derived neurons.
Chandelier Cells Control Excessive Cortical Excitation: Characteristics of Whisker-Evoked Synaptic Responses of Layer 2/3 Nonpyramidal and Pyramidal Neurons
Authors: Zhu Yinghua , Stornetta Ruth L. , Zhu J. Julius
Published: June 2004

Chandelier cells form inhibitory axo-axonic synapses on pyramidal neurons with their characteristic candlestick-like axonal terminals. The functional role of chandelier cells is still unclear, although the preferential loss of this cell type at epileptic loci suggests a role in epilepsy. Here we report an examination of whisker- and spontaneous activity-evoked responses in chandelier cells and other fast-spiking nonpyramidal neurons and regular-spiking pyramidal neurons in layer 2/3 of the barrel cortex. Fast-spiking nonpyramidal neurons, including chandelier cells, basket cells, neurogliaform cells, double bouquet cells, net basket cells, bitufted cells, and regular-spiking pyramidal neurons all respond to stimulation of multiple whiskers on the contralateral face. Whisker stimulation, however, evokes small, delayed EPSPs preceded by an earlier IPSP and no action potentials in chandelier cells, different from other nonpyramidal and pyramidal neurons. In addition, chandelier cells display a larger receptive field with lower acuity than other fast-spiking nonpyramidal neurons and pyramidal neurons. Notably, simultaneous dual whole-cellin vivorecordings show that chandelier cells, which rarely fire action potentials spontaneously, fire more robustly than other types of cortical neurons when the overall cortical excitation increases. Thus, chandelier cells may not process fast ascending sensory information but instead may be reserved to prevent excessive excitatory activity in neuronal networks.
Cytoplasmic Polyadenylation Element Binding Protein-Dependent Protein Synthesis Is Regulated by Calcium/Calmodulin-Dependent Protein Kinase II
Authors: Atkins Coleen M. , Nozaki Naohito , Shigeri Yasushi , Soderling Thomas R.
Published: June 2004

Phosphorylation of cytoplasmic polyadenylation element binding protein (CPEB) regulates protein synthesis in hippocampal dendrites. CPEB binds the 3′ untranslated region (UTR) of cytoplasmic mRNAs and, when phosphorylated, initiates mRNA polyadenylation and translation. We report that, of the protein kinases activated in the hippocampus during synaptic plasticity, calcium/calmodulin-dependent protein kinase II (CaMKII) robustly phosphorylated the regulatory site (threonine 171) in CPEBin vitro. In postsynaptic density fractions or hippocampal neurons, CPEB phosphorylation increased when CaMKII was activated. These increases in CPEB phosphorylation were attenuated by a specific peptide inhibitor of CaMKII and by the general CaM-kinase inhibitor KN-93. Inhibitors of protein phosphatase 1 increased basal CPEB phosphorylation in neurons; this was also attenuated by a CaM-kinase inhibitor. To determine whether CaM-kinase activity regulates CPEB-dependent mRNA translation, hippocampal neurons were transfected with luciferase fused to a 3′ UTR containing CPE-binding elements. Depolarization of neurons stimulated synthesis of luciferase; this was abrogated by inhibitors of protein synthesis, mRNA polyadenylation, and CaMKII. These results demonstrate that CPEB phosphorylation and translation are regulated by CaMKII activity and provide a possible mechanism for how dendritic protein synthesis in the hippocampus may be stimulated during synaptic plasticity.
Cocaine Self-Administration Selectively Decreases Noradrenergic Regulation of Metabotropic Glutamate Receptor-Mediated Inhibition in Dopamine Neurons
Authors: Paladini Carlos A. , Mitchell Jennifer M. , Williams John T. , Mark Gregory P.
Published: June 2004

Stimulant drugs of abuse have several effects on neural activity, including altering the excitability of dopamine neurons via the noradrenergic and glutamatergic systems. Thus, an interaction between noradrenergic and glutamatergic systems may play a role in drug-seeking behavior. Although many of the direct pharmacological effects of psychostimulants on dopamine neuron physiology are well established, the neurophysiological bases of drug-seeking behavior have yet to be fully elucidated. The present study measured short-term (3 d) and long-term (14 d) access to cocaine, by self-administration or passive exposure, and the regulation of metabotropic glutamate receptor (mGluR)-mediated inhibition of dopamine cells in rat midbrain slices. The results indicated that α-adrenoreceptor modulation of the mGluR-mediated inhibition is selectively reduced in animals that self-administered cocaine for 3 d. This effect was not observed in slices from either yoked cocaine animals, which were given cocaine in an amount and pattern equal to that used for the self-administering animals, or saline control animals. However, after 14 d of cocaine, α-adrenoreceptor regulation of the mGluR-mediated inhibition was equally reduced in both self-administering and yoked cocaine animals relative to saline controls. The results suggest that α-adrenoreceptor regulation of the mGluR-mediated inhibition is an adaptive cellular mechanism involved in early cocaine self-administration that is distinct from a direct pharmacological effect of cocaine on dopamine neurons. The noradrenergic system could therefore serve to alter the reward value of stimuli that have significant effects on dopamine neuron firing pattern through mGluRs.
A Specific Synaptic Pathway Activates a Conditional Plateau Potential Underlying Protraction Phase in theAplysiaFeeding Central Pattern Generator
Authors: Dembrow Nikolai C. , Jing Jian , Brezina Vladimir , Weiss Klaudiusz R.
Published: June 2004

A common feature in the architecture of neuronal networks is a high degree of seemingly redundant synaptic connectivity. In many cases, the synaptic inputs converging on any particular neuron all use the same neurotransmitter and appear to be fundamentally equivalent. Here, we analyze a striking counterexample in which such inputs are not equivalent and, as a result, play very different roles in the generation of the pattern of activity produced by the network. In the feeding central pattern generator ofAplysia, the pattern-initiating neuron B50 elicits motor programs by exciting the plateauing neuron B31/B32 in two ways: directly and indirectly through neuron B63. All of the synaptic connections use ACh. Despite the direct input of B50 to B31/B32, the indirect pathway of exciting B31/B32 through B63 is required for B50 to elicit the B31/B32 plateau potential and the motor program. We dissect this requirement using the muscarinic cholinergic antagonist pirenzepine. Pirenzepine blocks the B50-elicited motor program, the plateau potential in B31/B32, and, notably, a slow component of the EPSP elicited in B31/B32 by B63 but not that elicited by B50. The muscarinic agonist oxotremorine restores the plateau potential in B31/B32 and eliminates the necessity for B63 in B50-elicited motor programs. Together, our analysis shows that the plateau potential in B31/B32 is not endogenous but conditional, furthermore conditional on one particular synaptic input, that from B63. Thus, among several inputs to B31/B32 that use the same transmitter, the input from B63 is functionally distinct in its preferential access to the plateau potential that represents the committed step toward the initiation of a motor program.
Ab Initio Quantum Chemical and Molecular Dynamics Simulation Study of Lithium Iodide in Acetonitrile
Authors: Bakó Imre , Megyes Tünde , Radnai Tamás , Pálinkás Gábor , Probst Michael , Fawcett W. Ronald
Published: May 2004

Ab initio calculations for clusters containing Li+ and up to six acetonitrile molecules have been performed by using the B3LYP, MP2(FC) and MP2(Full) methods with the 6-311+G** basis set. The three computational methods give similar results for highly symmetric structures. In the case of MP2 calculation the inclusion of core electrons does not effect the values of the intermolecular distances and binding energy in the Li+-acetonitrile complex. The average ion–ligand distance increases with increasing number of acetonitrile molecules in the cluster. It has been shown that the energy required to incorporate an additional acetonitrile molecule in the Li-acetonitrile clusters containing 5 and 6 acetonitrile molecules is almost equal to the acetonitrile–acetonitrile interaction energy in the most stable acetonitrile dimer and therefore it is very difficult to predict whether the coordination sphere of Li+ contains four, five or six acetonitrile molecules. A molecular dynamics simulation has also been performed on LiI-acetonitrile system. The coordination number of the Li+ and I− have been found to be 5.97 and 14, respectively. The first solvation shell of Li+ has an octahedral geometry; the coordination sphere of the I− ion does not show any special arrangement.
Reliable Thermodynamic Properties of Electrolyte Solutions – A Survey of Existing Data Sources
Authors: Westhaus Ulrich , Sass Richard
Published: May 2004

Chemical engineers and physical chemists dealing either with model development or the design of chemical apparatus or processes containing electrolytes have a pressing need to access reliable thermodynamic property data of the systems they are dealing with. A survey of the existing, publicly available data collections focused on electrolytes is given.
Hydration of Molecular Anions with Oxygen Sites – a Monte Carlo Study
Authors: Krienke Hartmut , Schmeer Georg
Published: May 2004

Equilibrium properties of molecular model water (in pure phase and in electrolyte solutions) are calculated with the help of spatial pair correlation functions, starting from classical molecular pair interactions. Simulations were performed for a new simple water model derived from combined quantum-mechanical and statistical calculations in a SCF/SSOZ scheme.

Ion hydration of molecular anions with oxygen sites such as nitrate and perchlorate ions is of special interest when compared with hydration structures of spherical atomic anions like the halide ions. The water structure around the different solutes, and their influence on solution properties, is discussed.