bluuebunny/crossref_metadata_2025 huggingface dataset:
Phosphatidylinositol 4-Kinase: Gene Structure and Requirement for Yeast Cell Viability
Authors: Flanagan Catherine A. , Schnieders Elisabeth A. , Emerick Anne W. , Kunisawa Riyo , Admon Arie , Thorner Jeremy
Published: October 2006

Phosphatidylinositol (PtdIns) 4-kinase catalyzes the first step in the biosynthesis of PtdIns-4,5-
bis
phosphate (PtdIns[4,5]P
2
). Hydrolysis of PtdIns[4,5]P
2
in response to extracellular stimuli is thought to initiate intracellular signaling cascades that modulate cell proliferation and differentiation. The
PIK1
gene encoding a PtdIns 4-kinase from the yeast
Saccharomyces cerevisiae
was isolated by polymerase chain reaction (PCR) with oligonucleotides based on the sequence of peptides derived from the purified enzyme. The sequence of the
PIK1
gene product bears similarities to that of PtdIns 3-kinases from mammals (p110) and yeast (Vps34p). Expression of
PIK1
from a multicopy plasmid elevated PtdIns 4-kinase activity and enhanced the response to mating pheromone. A
pik1
null mutant was inviable, indicating that PtdIns4P and presumably PtdIns[4,5]P
2
are indispensable phospholipids.
Engineered Biosynthesis of Novel Polyketides
Authors: McDaniel Robert , Ebert-Khosla Susanne , Hopwood David A. , Khosla Chaitan
Published: October 2006

Polyketide synthases (PKSs) are multifunctional enzymes that catalyze the biosynthesis of a huge variety of carbon chains differing in their length and patterns of functionality and cyclization. Many polyketides are valuable therapeutic agents. A
Streptomyces
host-vector system has been developed for efficient construction and expression of recombinant PKSs. Using this expression system, several novel compounds have been synthesized in vivo in significant quantities. Characterization of these metabolites has provided new insights into key features of actinomycete aromatic PKS specificity. Thus, carbon chain length is dictated, at least in part, by a protein that appears to be distinctive to this family of PKSs, whereas the acyl carrier proteins of different PKSs can be interchanged without affecting product structure. A given ketoreductase can recognize and reduce polyketide chains of different length; this ketoreduction always occurs at the C-9 position. The regiospecificity of the first cyclization of the nascent polyketide chain is either determined by the ketoreductase, or the chain-extending enzymes themselves. However, the regiospecificity of the second cyclization is determined by a distinct cyclase, which can discriminate between substrates of different chain lengths.
Coronary Tone Modulation: Formation and Actions of Prostaglandins, Endoperoxides, and Thromboxanes
Authors: Needleman Philip , Kulkarni Prasad S. , Raz Amiram
Published: October 2006

Exogenous prostaglandin (PGE2) contracts bovine and human coronary arteries but its precursor, arachidonic acid, relaxes them. The endoperoxides PGH2and PGH3relax bovine coronary strips, but PGH1produces contraction. The primary prostaglandins exert opposite effects to their own endoperoxide precursors, thus, PGE2and PGE3contract, and PGE1relaxes the bovine coronary arteries. The paradoxical coronary dilation produced by the arachidonate or the PGH2suggest that little if any coronary isomerase which converts endoperoxide into PGE2exists, or that a novel, potent, PG-like substance is produced by the isolated coronary arteries. Although the coronaries do not possess thromboxane A2synthetase activity, the vessels are profoundly contracted by exogenous thromboxane A2. Thromboxane A2can be synthesized and released by circulating platelets when they are aggregated by endothelial injury or thrombin. Thus, coronary tone, and possible spasm, in ischemic myocardial zones may be influenced markedly by interplay between prostaglandins, endoperoxides, and thromboxane formed by platelets on the one hand, and endoperoxide products synthesized endogenously in the coronary arteries on the other.
Genetic Algorithms: Principles of Natural Selection Applied to Computation
Authors: Forrest Stephanie
Published: October 2006

A genetic algorithm is a form of evolution that occurs on a computer. Genetic algorithms are a search method that can be used for both solving problems and modeling evolutionary systems. With various mapping techniques and an appropriate measure of fitness, a genetic algorithm can be tailored to evolve a solution for many types of problems, including optimization of a function or determination of the proper order of a sequence. Mathematical analysis has begun to explain how genetic algorithms work and how best to use them. Recently, genetic algorithms have been used to model several natural evolutionary systems, including immune systems.
A Mechanism for Ion Selectivity in Potassium Channels: Computational Studies of Cation-π Interactions
Authors: Kumpf Robert A. , Dougherty Dennis A.
Published: October 2006

A combination of computational methods has been used to evaluate the interaction between the π face of a benzene molecule and the monovalent cations of lithium, sodium, potassium, and rubidium. In the gas phase, the ions are strongly bound, and the affinity for benzene follows the expected electrostatic trend (lithium, largest; rubidium, smallest). However, in an aqueous environment, a reordering occurs such that the potassium ion is preferred over all the other ions for 2:1 benzene:ion complexes. The selectivity sequence parallels that seen in voltage-gated potassium channels. Given that several conserved aromatic residues are present in the pore region of such channels, these results suggest that the cation-π interaction may be responsible for the ion selectivity in potassium channels.
Tyrosine Phosphorylation of DNA Binding Proteins by Multiple Cytokines
Authors: Larner Andrew C. , David Michael , Feldman Gerald M. , Igarashi Ken-ichi , Hackett Rebecca H. , Webb Deborah S. A. , Sweitzer Sharon M. , Petricoin Emanuel F. , Finbloom David S.
Published: October 2006

Interferon-α (IFN-α) and IFN-γ regulate gene expression by tyrosine phosphorylation of several transcription factors that have the 91-kilodalton (p91) protein of interferon-stimulated gene factor-3 (ISGF-3) as a common component. Interferon-activated protein complexes bind enhancers present in the promoters of early response genes such as the high-affinity Fcγ receptor gene (FcγRI). Treatment of human peripheral blood monocytes or basophils with interleukin-3 (IL-3), IL-5, IL-10, or granulocyte-macrophage colony-stimulating factor (GM-CSF) activated DNA binding proteins that recognized the IFN-γ response region (GRR) located in the promoter of the FcγRI gene. Although tyrosine phosphorylation was required for the assembly of each of these GRR binding complexes, only those formed as a result of treatment with IFN-γ or IL-10 contained p91. Instead, complexes activated by IL-3 or GM-CSF contained a tyrosine-phosphorylated protein of 80 kilodaltons. Induction of FcγRI RNA occurred only with IFN-γ and IL-10, whereas pretreatment of cells with GM-CSF or IL-3 inhibited IFN-γ induction of FcγRI RNA. Thus, several cytokines other than interferons can activate putative transcription factors by tyrosine phosphorylation.
Rate and Mechanism of Nonhomologous Recombination During a Single Cycle of Retroviral Replication
Authors: Zhang Jiayou , Temin Howard M.
Published: October 2006

Oncogenes discovered in retroviruses such as Rous sarcoma virus were generated by transduction of cellular proto-oncogenes into the viral genome. Several different kinds of junctions between the viral and proto-oncogene sequences have been found in different viruses. A system of retrovirus vectors and a protocol that mimicked this transduction during a single cycle of retrovirus replication was developed. The transduction involved the formation of a chimeric viral-cellular RNA, strand switching of the reverse transcription growing point from an infectious retrovirus to the chimeric RNA, and often a subsequent deletion during the rest of viral DNA synthesis. A short region of sequence identity was frequently used for the strand switching. The rate of this process was about 0.1 to 1 percent of the rate of homologous retroviral recombination.
Hepatic Regeneration and Erythropoietin Production in the Rat
Authors: Naughton Brian A. , Kaplan Stephen M. , Roy Martin , Burdowski Allen J. , Gordon Albert S. , Piliero Sam J.
Published: October 2006

The regenerating liver produces erythropoietin in response to hypoxia. The amounts of erythropoietin produced in animals subjected to hepatectomy are significantly higher than those observed in sham-operated animals. Hepatic erythropoietin production appears to be dependent upon the stage of regeneration with the highest levels being produced during the period of greatest proliferation and increase in liver mass.
Clues to the Pathogenesis of Familial Colorectal Cancer
Authors: Aaltonen Lauri A. , Peltomäki Päivi , Leach Fredrick S. , Sistonen Pertti , Pylkkänen Lea , Mecklin Jukka-Pekka , Järvinen Heikki , Powell Steven M. , Jen Jin , Hamilton Stanley R. , Petersen Gloria M. , Kinzler Kenneth W. , Vogelstein Bert , de la Chapelle Albert
Published: October 2006

A predisposition to colorectal cancer is shown to be linked to markers on chromosome 2 in some families. Molecular features of "familial" cancers were compared with those of sporadic colon cancers. Neither the familial nor sporadic cancers showed loss of heterozygosity for chromosome 2 markers, and the incidence of mutations inKRAS,P53, andAPCwas similar in the two groups of tumors. Most of the familial cancers, however, had widespread alterations in short repeated DNA sequences, suggesting that numerous replication errors had occurred during tumor development. Thirteen percent of sporadic cancers had identical abnormalities and these cancers shared biologic properties with the familial cases. These data suggest a mechanism for familial tumorigenesis different from that mediated by classic tumor suppressor genes.
The Status of the Gene Map of the Human Chromosomes
Authors: McKusick Victor A. , Ruddle Frank H.
Published: October 2006

In man, the specific chromosome that carries each of about 210 gene loci is known. These loci include at least one assigned to each chromosome (including the Y), about 110 assigned to specific autosomes, and about 100 to the X chromosome. For many loci, information on regional chromosomal localization is also available. The information comes mainly from studies in families and somatic cell hybrids, as well as an integration of results from the two methods.

Knowledge of the chromosome map gives insight into evolution, chromosomal organization in relation to genetic control mechanisms, and the pathogenesis of neoplasms and malformations. Furthermore, it is useful in prenatal or premorbid diagnosis of hereditary diseases.
Schedule Control of Behavior Reinforced by Electrical Stimulation of the Brain
Authors: Beninger Richard J. , Bellisle France , Milner Peter M.
Published: October 2006

Electrical stimulation of the brain was used to train rats to respond on random interval schedules. Stimulation was either delayed for 0.5 second and preceded by a brief signal, delayed and unsignaled, or presented contiguously with the response. In every case, responding was maintained on schedules and showed resistance to extinction typical of food-reinforced responding. Priming was never necessary. These data cast doubt on the generality of beliefs about the behavioral effects of brain stimulation reinforcement.
Pesticide Uptake into Membranes Measured by Fluorescence Quenching
Authors: Omann Geneva , Lakowicz Joseph R.
Published: October 2006

Pesticides that contain chlorine have been shown to quench the fluorescence of carbazole-labeled phospholipids. Incorporation of these carbazole-labeled phospholipids into model membranes provides a system that allows the rapid determination of the uptake rates of chlorinated hydrocarbons into model membranes. This technique can be used in the determination of diffusion rates and partition coefficients of chlorine-containing organic compounds in model membrane systems, and hence may provide a method by which the bioaccumulation potential of synthetic chlorine-containing compounds can be estimated.
Synaptic Mechanism of Pentylenetetrazole: Selectivity for Chloride Conductance
Authors: Pellmar T. C. , Wilson W. A.
Published: October 2006

In the neurons ofAplysia californicapentylenetetrazole (2 millimolar) greatly reduced chloride-dependent responses to the iontophoresis of putative transmitters. At the same concentration, pentylenetetrazole caused less attenuation of the other iontophoretic responses and had minimal membrane effects. Several convulsants have been observed to have a similar selectivity for the chloride conductance. A common mechanism of convulsant action—reduction of transmitter-induced chloride conductances—is hypothesized.
Long-Term Unit Recording from Somatosensory Neurons in the Spinal Ganglia of the Freely Walking Cat
Authors: Loeb G. E. , Bak M. J. , Duysens J.
Published: October 2006

A new technique has been developed for stable, long-term recording from groups of individual primary afferent neurons in the freely walking cat. A number of fine, flexible wires are inserted into dorsal root ganglia via a small laminotomy in the lumbar spine. The cut end of each wire can record stable and separable action potentials from one to three dorsal root ganglion neurons; each unit has typically held for 1 to 4 days. A broad range of myelinated somatosensory afferents (conduction velocities of 30 to 120 meters per second) have been studied during locomotion. Most cutaneous and proprioceptive afferents studied have been sensitive monitors of complex combinations of step-cycle components, and their firing patterns would often have been difficult to predict from existing information.
Butylated Hydroxytoluene Protects Chickens Exposed to Newcastle Disease Virus
Authors: Brugh Max
Published: October 2006

Dietary butylated hydroxytoluene, an antioxidant widely used in food and feed processing, prevents mortality of chickens exposed to virulent Newcastle disease virus and prevents the serological response of chickens exposed to avirulent Newcastle disease virus. This chemoprophylactic effect is evident when chickens are fed diets containing concentrations of butylated hydroxytoluene normally used for antioxidant purposes (100 to 200 parts per million of total diet).
Reinnervation of Dentate Gyrus by Homologous Afferents Following Entorhinal Cortical Lesions in Adult Rats
Authors: Steward Oswald
Published: October 2006

Granule cells of the rat dentate gyrus which are denervated by unilateral destruction of the entorhinal cortex are reinnervated in part by proliferation of surviving pathways from the contralateral entorhinal cortex. The cells of origin of these lesion-induced projections were identified by retrograde labeling with horseradish peroxidase and were the same cell type which normally project to the ipsilateral dentate gyrus
Do circulating leucocytes and lymphocyte subtypes increase in response to brief exercise in children with and without asthma?
Authors: Schwindt C D , Zaldivar F , Wilson L , Leu S-Y , Wang-Rodriguez J , Mills P J , Cooper D M
Published: October 2006

Background:Exercise can alter health in children in both beneficial (eg reduced long-term risk of atherosclerosis) and adverse (eg exercise-induced asthma) ways. The mechanisms linking exercise and health are not known, but may rest, partly, on the ability of exercise to increase circulating immune cells. Little is known about the effect of brief exercise, more reflective of naturally occurring patterns of physical activity in children, on immune cell responses.

Objectives:To determine whether (1) a 6-min bout of exercise can increase circulating inflammatory cells in healthy children and (2) the effect of brief exercise is greater in children with a history of asthma.

Methods:Children with mild–moderate persistent asthma and age-matched controls (n = 14 in each group, mean age 13.6 years) performed a 6-min bout of cycle-ergometer exercise. Spirometry was performed at baseline and after exercise. Blood was drawn before and after exercise, leucocytes were quantified and key lymphocyte cell surface markers were assessed by flow cytometry.

Results:Exercise decreased spirometry only in children with asthma, but increased (p<0.001) most types of leucocytes (eg lymphocytes (controls, mean (SD) 1210 (208) cells/μl; children with asthma, 1119 (147) cells/μl) and eosinophils (controls, 104 (22) cells/μl; children with asthma, 88 (20) cells/μl)) to the same degree in both groups. Similarly, exercise increased T helper cells (controls, 248 (60) cells/μl; children with asthma, 232 (53) cells/μl) and most other lymphocyte subtypes tested. By contrast, although basophils (16 (5) cells/μl) and CD4+ CD45RO+ RA+ lymphocytes (19 (4) cells/μl) increased in controls, no increase in these cell types was found in children with asthma.

Conclusions:Exercise increased many circulating inflammatory cells in both children with asthma and controls. Circulating inflammatory cells did increase in children with asthma, but not to a greater degree than in controls. In fact, basophils and T helper lymphocyte memory transition cells did not increase in children with asthma, whereas they did increase in controls. Even brief exercise in children and adolescents robustly mobilises circulating immune cells.
DYNAMIC DIPOLE AND QUADRUPOLE PHASE TRANSITIONS IN THE KINETIC SPIN-1 MODEL
Authors: KESKİN MUSTAFA , CANKO OSMAN , KANTAR ERSIN
Published: October 2006

The dynamic phase transitions have been studied, within a mean-field approach, in the kinetic spin-1 Ising model Hamiltonian with arbitrary bilinear and biquadratic pair interactions in the presence of a time varying (sinusoidal) magnetic field by using the Glauber-type stochastic dynamics. The nature (first- or second-order) of the transition is characterized by investigating the behavior of the thermal variation of the dynamic order parameters. The dynamic phase transitions (DPTs) are obtained and the phase diagrams are constructed in the temperature and magnetic field amplitude plane and found six fundamental types of phase diagrams. Phase diagrams exhibit one or two dynamic tricritical points depending on the biquadratic interaction (K). Besides the disordered (D) and ferromagnetic (F) phases, the FQ + D, F + FQ and F + D coexistence phase regions also exist in the system and the F and F + D phases disappear for high values of K.
GENERALIZED SYNCHRONIZATION IN DOUBLY DRIVEN CHAOTIC SYSTEM
Authors: HUANG XIA , GAO JIAN , HE DAIHAI , ZHENG ZHIGANG
Published: October 2006

Generalized synchronization (GS) of a chaotic oscillator driven by two chaotic signals is investigated in this paper. Both receiver and drivers are the same kind of oscillators with mismatched parameter values. Partial and global GS may appear depending on coupling strengths. An approach based on the conditional entropy analysis is presented to test the partial GS, which is difficult to determine with conventional methods. A trough in conditional entropy spectrum indicates partial GS between the receiver and one of the drivers.
QUANTUM TREATMENT OF THREE MUTUALLY ANISOTROPIC COUPLED OSCILLATORS
Authors: NASSAR M. M. , SEBAWE ABDALLA M.
Published: October 2006

A full quantum mechanical treatment of the problem of three electromagnetic fields is considered. The system consists of three different coupling parameters where the rotating and counter-rotating terms are presented. An exact solution of the wave function in the Schrödinger picture is obtained, and the connection to the coherent states wave function is given. The symmetrical ordered quasi-probability distribution function (W-Wigner function) is calculated via the wave function in the coherent states representation. The Green's function is obtained and employed to find the Bloch density matrix. The expectation value of the energy is also given. In the framework of the vacuum and even coherent states, we have discussed the phenomenon of squeezing. It has been shown that the collapse and revival phenomenon exists at ω1=ω2 and is apparent for a long period of time.
THE STUDY OF COUPLED OSCILLATORS ON CLASSICAL CHAOS AND QUANTUM CHARACTERISTIC
Authors: YANG SHI-PING , LI YAN , CHANG HONG , TIAN GANG , YUAN GUO-YONG
Published: October 2006

In this paper, the classical and quantum chaos characteristic of single electronic motion in the double quantum well with external magnetic field are studied. The system can be regarded as the linear coupling of a harmonic oscillator and a Duffing oscillator. The study shows that because of the interaction of two oscillators, the system demonstrates the characteristic of quasi-periodicity, multi-chaos coexisting attractors, chaos, super-chaos, etc., with different energy. Furthermore, as shown in the corresponding analysis of spectrum distribution statistics, the system in most energy fields demonstrates the coexisting of the integrable and non-integrable characteristic, which means that there is a close corresponding relation in classical and quantum behavior.
Smoking in film in New Zealand: measuring risk exposure
Authors: Gale Jesse , Fry Bridget , Smith Tara , Okawa Ken , Chakrabarti Anannya , Ah-Yen Damien , Yi Jesse , Townsend Simon , Carroll Rebecca , Stockwell Alannah , Sievwright Andrea , Dew Kevin , Thomson George
Published: October 2006

Background

Smoking in film is a risk factor for smoking uptake in adolescence. This study aimed to quantify exposure to smoking in film received by New Zealand audiences, and evaluate potential interventions to reduce the quantity and impact of this exposure.

Methods

The ten highest-grossing films in New Zealand for 2003 were each analysed independently by two viewers for smoking, smoking references and related imagery. Potential interventions were explored by reviewing relevant New Zealand legislation, and scientific literature.

Results

Seven of the ten films contained at least one tobacco reference, similar to larger film samples. The majority of the 38 tobacco references involved characters smoking, most of whom were male. Smoking was associated with positive character traits, notably rebellion (which may appeal to adolescents). There appeared to be a low threshold for including smoking in film. Legislative or censorship approaches to smoking in film are currently unlikely to succeed. Anti-smoking advertising before films has promise, but experimental research is required to demonstrate cost effectiveness.

Conclusion

Smoking in film warrants concern from public health advocates. In New Zealand, pre-film anti-smoking advertising appears to be the most promising immediate policy response.
Pax2/5/8 proteins promote cell survival inC. elegans
Authors: Park DonHa , Jia Hongtao , Rajakumar Vandana , Chamberlin Helen M.
Published: October 2006

Programmed cell death, or apoptosis, plays an important role during normal development, and is disrupted in a range of disease states. Although the key molecular events that occur during apoptosis are well characterized, less is known about the regulatory inputs that influence whether a cell will live or die. Work in mouse and human cells has shown that Pax transcription factors can influence cell death and promote cell survival, but the mechanism for their activity is not clear. Here, we show that two Pax2/5/8-related genes (egl-38 and pax-2) influence both somatic and germline cell death in C. elegans. Using genetic and molecular experiments, we show that the Pax proteins act as transcriptional regulators of ced-9, the C. elegans bcl-2 gene. These results identify a mechanism for Pax2/5/8-mediated regulation of cell death, and underscore the importance of transcriptional regulation of core apoptotic pathway genes in influencing cell survival.
Combined otoneurosurgical approach to patients with chronic ear disease and cerebrospinal otorrhea
Authors: Abramson Maxwell , Mcmurtry James G. , Kadis Gerald
Published: October 2006

We report a combined otoneurosurgical approach in the treatment of a patient with meningitis due to an arachnoid cyst, extending through the dura and petrous bone into the middle ear. The combination of mastoid surgery and temporal craniotomy including opening the dura was necessary to determine the nature of the problem, excise the disease and repair the defects.

Two recent cases at our Institution of cerebrospinal otorhinorrhea and chronic ear disease illustrate the difficulty in carrying out definitive repair of dural defects from within the mastoid cavity. Case 2 had three bouts of meningitis and two brain abscesses separated by 25 years. Case 3 had eight bouts of meningitis in 19 years.

The authors recommend an otoneurosurgical team approach in patients with cerebrospinal otorhinorrhea permitting treatment of the temporal bone, dura and brain.
Hemilaryngectomy for verrucous carcinoma of the glottis
Authors: Myers Ernest , Sobol Steven , Ogura Joseph H.
Published: October 2006

Seven patients with verrucous carcinoma of the glottis treated by hemilaryngectomy are analyzed. The diagnostic criteria for this tumor are reviewed. Close cooperation between the clinician and pathologist is necessary for the correct diagnosis. The controversy regarding radiation therapy is discussed. Hemilaryngectomy is concluded to be a successful surgical modality for limited verrucous carcinoma of the larynx.
Bilateral sensorineural hearing loss associated with mycoplasma pneumoniae infection
Authors: Nishioka Keiko , Masuda Yu , Okada Satoko , Takata Nobuaki , Tasaka Shuji , Ogura Yoshio
Published: October 2006

Three cases of persistent bilateral sensorineural hearing loss following Mycoplasma pneumoniae (MP) infection are reported. These cases were characterized by highly elevated MP complement fixation titer and cold hemagglutinin titer. All the patients had bilateral acute otitis media with a moderate to high degree of mixed hearing loss in the early stage following primary atypical pneumonia (PAP).
The British Image of Spain and the Civil War
Authors: Moradiellos Enrique
Published: October 2006

This article aims to examine those images of Spain and Spaniards which were dominant in Great Britain during the Spanish Civil War, 193639. Its basic conclusion is that these images corresponded to two large sets of stereotypes bequeathed by history (the Black Legend of the sixteenth
century and Romantic Myth of the nineteenth century) and were used as appropriate by both supporters of the Republic and of Franco in their respective propaganda battles.
Bulky‐Hindrance‐Controlled Ligand Transformation from Linked Bis(amidinate) to Linked Imido‐Amidinate Promoted by a Mono(cyclopentadienyl)titanium Group
Authors: Bai Sheng‐Di , Guo Jian‐Ping , Liu Dian‐Sheng , Wong Wai‐Yeung
Published: October 2006

A novel class of silyl‐linked bis(amidinate) ligands [SiMe2{NC(Ph)N(2,6‐R2Ph)Li}2] [L1 (R = H), L2 (R = Me), and L3 (R = iPr)] reacted with TiCl3(C5H5) to produce the half‐sandwich titanium complexes 1, 2, and 3. The molecular structures of 1–3 were confirmed successfully by X‐ray crystallography. An unprecedented intramolecular ligand transformation from the linked bis(amidinate) configuration to the linked imido‐amidinate configuration took place in the cases of L1 and L2. It was found that the rearrangement process was related to the steric hindrance of the terminal substituents. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Direct Asymmetric α‐Sulfamidation of α‐Branched Aldehydes: A Novel Approach to Enamine Catalysis
Authors: Vogt Henning , Baumann Thomas , Nieger Martin , Bräse Stefan
Published: October 2006

Proline‐catalysed reactions between α‐branched aldehydes and sulfonyl azides provide scalemic configurationally stabilised α‐sulfamidated products with ee values of up to 86 %. The reactions can also be carried out in a one‐pot fashion, with catalyst, aldehyde, sulfonyl chloride and sodium azide. The proposed mechanism differs fundamentally from the mechanistic model usually ascribed to enamine catalysis, containing as a key step the diastereoselective cycloaddition of the azide to an enamine formed in situ. The products obtained in the reaction can be converted into the corresponding unnatural amino acids in two additional steps.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A rare case of granulomatous prostatitis caused by Mycobacterium tuberculosis
Authors: Tamsel Sadýk , Killi Refik , Ertan Yesim , Demirpolat Gulgun
Published: October 2006

We report a rare case of infective granulomatous prostatitis caused by Mycobacterium tuberculosis that may be mistaken for prostatic carcinoma, both on clinical examination and transrectal sonography (TRUS). A large hypoechoic mass was detected in the prostate of a 46‐year‐old man during TRUS and histopathologic examination after TRUS‐guided biopsies reported the diagnosis of tuberculous prostatitis. We herein describe the clinical and TRUS findings of this case. © 2006 Wiley Periodicals, Inc. J Clin Ultrasound, 2006
An apparent unidirectional influx constant for manganese as a measure of myocardial calcium channel activity
Authors: Skjold Arne , Kristoffersen Anders , Vangberg Torgil R , Haraldseth Olav , Jynge Per , Larsson Henrik BW
Published: October 2006

Purpose

To develop an in vivo MR method for evaluation of myocardial calcium channel activity through quantification of apparent unidirectional manganese influx constants following manganese dipyridoxyl‐diphosphate (MnDPDP) infusions.

Materials and Methods

A total of 10 healthy volunteers were divided in two groups, and received 5 μmol of MnDPDP per kg of body weight intravenously in a 1.5 Tesla scanner over five or 30 minutes, respectively. A fast inversion recovery gradient echo sequence was used to estimate pre‐ and postcontrast R1 values and to measure signal changes following infusions. By assuming equal longitudinal relaxivity (r1) of the contrast in all tissue compartments, signal changes in blood and myocardial tissue yielded temporal input and tissue contrast concentrations respectively. Through a two‐tissue compartment model, apparent unidirectional influx constants (Ki) for myocardial manganese accumulation were estimated.

Results

Consistent values for Ki in left ventricular wall were found, with a mean value of 5.96 mL/100 g/minute (SD = 0.49; N = 10). No statistical significant differences in Ki were found between the two infusion groups.

Conclusion

Since unidirectional manganese accumulation depends upon intact myocyte membranes with functioning calcium channels, the use of unidirectional manganese influx rates may be a valuable research tool for in vivo studies of myocyte functioning in myocardial disease. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Regioselective Grafting of Poly(ethylene glycol) onto Chitosan and the Properties of the Resulting Copolymers
Authors: Liu Li , Li Fangzhi , Fang Yue'e , Guo Shengrong
Published: October 2006

Summary: PEG was grafted onto chitosan regioselectively at the hydroxyl groups with phthaloylchitosan as an intermediate. After the graft reaction, the phthaloyl groups were deprotected to give chitosan‐g‐PEG copolymers with free amino groups. The chemical structure of the graft copolymers was confirmed by FT‐IR, 1H and 13C NMR spectroscopy. The resulting graft copolymers showed improved thermal stability compared to the original chitosan, and showed a lower thermal transition temperature at around 185 °C. Chitosan‐g‐PEG exhibited a high affinity not only for aqueous acid but also for some organic solvents because of the presence of abundant free amino groups and PEG branches, and it exhibited higher hygroscopicity and moisture retention ability than chitosan.

magnified image
A linear complementarity formulation on position level for frictionless impact of planar deformable bodies
Authors: Ebrahimi S. , Eberhard P.
Published: October 2006

In this paper, we present an approach for frictionless impact of planar deformable bodies by formulating a linear complementarity problem on position level. This approach is based on the enforcing the Signorini conditions for the impact problem of continua. In doing so, first the bodies are discretized in finite elements and condensed with a finite number of eigenmodes. The equations of motion of the deformable bodies are generated using the well know moving frame of reference approach. Then, the normal gaps between the two impacting bodies are written in terms of the generalized coordinates. In the next step, by following different integration methods the generalized acceleration vector obtained from the equations of motion will be integrated to reach a relationship for the generalized coordinates. At the end, by substituting the generalized coordinates in the relationship of normal gaps, the impact problem is formulated as a linear complementarity problem. Solving this problem leads to the solution of our impact problem considering impact forces and normal gaps. At this point it should be emphasized that in this formulation no coefficient of restitution has to be introduced for obtaining the impact law. Although there exist some approaches for impact modeling of deformable bodies which introduce this coefficient as a measure of energy loss during impact, no coefficient of restitution should be used since the energy loss is taken into account by the damping in the material law of the deformable bodies.
The generalized‐α method in mechatronic applications
Authors: Brüls O. , Golinval J.C.
Published: October 2006

This paper presents an extension of the generalized‐α time‐integrator to mechatronic systems represented by coupled first and second‐order DAEs. A simple reformulation of those equations as full second‐order DAEs allows the implementation of a monolithic integration scheme, so that the numerical dissipation properties are preserved, and second‐order accuracy is obtained at least in the unconstrained case. The algorithmic parameters can be optimized either for the mechanical or the control subsystem. Two illustrative applications are treated in the fields of vehicle dynamics and robotics.
DAE time integration for real‐time applications in multi‐body dynamics
Authors: Burgermeister B. , Arnold M. , Esterl B.
Published: October 2006

The equations of motion of multi‐body systems with kinematically closed loops are given by differential‐algebraic equations (DAE). Real‐time applications like hardware‐in‐the‐loop testbeds or driving simulators require appropriate integration methods that can solve the non‐linear constraints without exceeding an a priori fixed number of calculation steps. Partitioned linear‐implicit Euler methods can be extended by appropriate stabilization techniques to keep the error in the constraints bounded for arbitrary time intervals. These methods need a fixed low number of operations for each time step. One simplified Newton step for the projection onto the constraint manifold can prevent the drift‐off for arbitrary time intervals if the stepsize is sufficiently small. Selected methods were successfully implemented in the commercial vehicle simulation package veDYNA to improve substantially the simulation capabilities for vehicle‐trailer coupling.
Recent changes in heart failure hospitalisations in Australia
Authors: Najafi Farid , Dobson Annette J. , Jamrozik Konrad
Published: October 2006

Aim:

To assess trends in admissions of patients with heart failure (HF) to all hospitals in Australia between 1996–1997 and 2003–2004.

Methods and results:

We carried out a retrospective analysis of the official population‐based National Hospital Morbidity Data in Australia. Although the absolute number of separations with a principal diagnosis of HF remained stable, the age‐ and sex‐standardized separation rate for HF recorded as principal diagnosis decreased from 2.0 per 1000 population in 1996–1997 to 1.6 per 1000 population in 2003–2004. The corresponding values for HF recorded in any diagnostic position were 7.7 and 4.7 per 1000 population. Men had higher in‐hospital mortality than women (8.9% versus 8.1%, p<0.001) and also a larger decrease in this measure over the study period (21.9% versus 14.4%). While the geometric mean length of stay for HF as principal diagnosis fell from 5.4days in 1996–1997 to 4.9days in 2003–2004, the proportion of bed‐days related to such diagnoses relative to total bed days attributed to circulatory diseases increased from 12.8% to 13.7% (p<0.001).

Conclusion:

There were no increase in number of admissions involving HF and standardized rates of hospital separations with HF fell in Australia between 1996 and 2004. The explanation for the observed declines in in‐hospital case fatality and the separation rates should be sought in whole‐of‐community studies.
The study of state-selected ion-molecule reactions using the vacuum ultraviolet pulsed field ionization-photoion technique
Authors: Dressler Rainer A. , Chiu Y. , Levandier D. J. , Tang X. N. , Hou Y. , Chang C. , Houchins C. , Xu H. , Ng Cheuk-Yiu
Published: October 2006

This paper presents the methodology to generate beams of ions in single quantum states for bimolecular ion-molecule reaction dynamics studies using pulsed field ionization (PFI) of atoms or molecules in high-n Rydberg states produced by vacuum ultraviolet (VUV) synchrotron or laser photoexcitation. Employing the pseudocontinuum high-resolution VUV synchrotron radiation at the Advanced Light Source as the photoionization source, PFI photoions (PFI-PIs) in selected rovibrational states have been generated for ion-molecule reaction studies using a fast-ion gate to pass the PFI-PIs at a fixed delay with respect to the detection of the PFI photoelectrons (PFI-PEs). The fast ion gate provided by a novel interleaved comb wire gate lens is the key for achieving the optimal signal-to-noise ratio in state-selected ion-molecule collision studies using the VUV synchrotron based PFI-PE secondary ion coincidence (PFI-PESICO) method. The most recent development of the VUV laser PFI-PI scheme for state-selected ion-molecule collision studies is also described. Absolute integral cross sections for state-selected H2+ ions ranging from v+=0 to 17 in collisions with Ar, Ne, and He at controlled translational energies have been obtained by employing the VUV synchrotron based PFI-PESICO scheme. The comparison between PFI-PESICO cross sections for the H2+(HD+)+Ne and H2+(HD+)+He proton-transfer reactions and theoretical cross sections based on quasiclassical trajectory (QCT) calculations and three-dimensional quantum scattering calculations performed on the most recently available ab initio potential energy surfaces is highlighted. In both reaction systems, quantum scattering resonances enhance the integral cross sections significantly above QCT predictions at low translational and vibrational energies. At higher energies, the agreement between experiment and quasiclassical theory is very good. The profile and magnitude of the kinetic energy dependence of the absolute integral cross sections for the H2+(v+=0–2,N+=1)+He proton-transfer reaction unambiguously show that the inclusion of Coriolis coupling is important in quantum dynamics scattering calculations of ion-molecule collisions.
Coactivator as a target gene specificity determinant for histone H3 lysine 4 methyltransferases
Authors: Lee Seunghee , Lee Dong-Kee , Dou Yali , Lee Jeongkyung , Lee Bora , Kwak Eunyee , Kong Young-Yun , Lee Soo-Kyung , Roeder Robert G. , Lee Jae W.
Published: October 2006

Activating signal cointegrator-2 (ASC-2), a coactivator of multiple transcription factors that include retinoic acid receptor (RAR), associates with histone H3-K4 methyltranferases (H3K4MTs) MLL3 and MLL4 in mixed-lineage leukemia. Here, we show that mice expressing a SET domain mutant of MLL3 share phenotypes with isogenic
ASC2
+/−
mice and that expression and H3-K4 trimethylation of RAR target gene
RAR
-β
2
are impaired in ASC-2-null mouse embryo fibroblasts (MEFs) or in MEFs expressing siRNAs against both MLL3 and MLL4. We also show that MLL3 and MLL4 are found in distinct ASC-2-containing complexes rather than in a common ASC-2 complex, and they are recruited to
RAR
-β
2
by ASC-2. In contrast, RAR-β2 expression is intact in MEFs devoid of menin, a component of MLL1 and MLL2 H3K4MT complexes. These results suggest that ASC-2 confers target gene specificity to MLL3 and MLL4 H3K4MT complexes and that recruitment of H3K4MTs to their target genes generally involves interactions between integral components of H3K4MT complexes and transcription factors.
Measurement of oedema in irritant‐exposed skin by a dielectric technique
Authors: Miettinen M. , Mönkkönen J. , Lahtinen M.‐R. , Nuutinen J. , Lahtinen T.
Published: October 2006

Background: Easily applicable water‐specific instruments measuring local oedema in skin are not available. The aim of this study is to demonstrate quantitative assessment of skin oedema with the dielectric technique by measuring increase of skin water content related to sodium lauryl sulphate (SLS)‐induced irritant contact dermatitis.

Methods: Irritant skin reaction and resulting oedema were induced by an irritant patch test on volar forearms in 12 healthy volunteers with the application of 1% SLS for 6 h. After occlusion the volunteers were divided into two groups: the patch test site of group I (six volunteers) received no treatment other than a base cream for the skin reaction, while for group II (six volunteers) a strong corticosteroid (clobetasol propionate) was applied on the irritant skin. During a follow‐up of 72 h, erythema was scored visually, and irritant‐induced oedema was measured with a novel water‐specific instrument MoistureMeter‐D.

Results: In the untreated irritant skin, a maximum increase of 45% in skin water content was found at 10 h postocclusion and water content was still elevated at 72 h. With these persons, the degree of oedema agreed well with the ultrasound‐measured skin thickness (P=0.053). In the corticosteroid‐treated skin, an increase of 8% in water content was measured during 72 h but there was no correlation between oedema and skin thickness. There was no correlation between erythema and oedema in untreated or corticosteroid‐treated skin.

Conclusion: The new instrument can easily be applied for noninvasive quantitative evaluation of local oedema and fluid retention in irritant‐exposed skin.
THE QUANTITATIVE HISTOCHEMISTRY OF A CHEMICALLY INDUCED EPENDYMOBLASTOMA–I ENZYMES*
Authors: Lehrer Gerard M. , Maker Howard S. , Silides Demetra J. , Weiss Cipora , Scheinberg Labe C.
Published: October 2006

Enzymes from several metabolic pathways were studied quantitatively in homogenates and in homogeneous areas of frozen‐dried cryostat sections of an experimental, mouse ependymoblastoma, mouse mammary carcinoma, and mouse melanoma, growing as transplants in mouse brain. Micro analyses were performed in fiveto sixfold replicates on portions of tumour with a dry weight of 0·03‐0·2 μg. A close resemblance of the enzyme spectrum of the ependymoblastoma to that of immature brain was noted. Hexokinase and malate dehydrogenase were lower and lactate, glucose‐6‐phosphate, and NADP+‐linked isocitrate dehydrogenases, and β‐glucuronidase higher in the ependymoblastoma than in whole, adult mouse brain. Mouse mammary carcinoma had a higher level of hexokinase and lower levels of lactate and glucose‐6‐phosphate dehydrogenases and β‐glucuronidase than ependymoblastoma. The concentration of malate dehydrogenase was lower and that of lactate, glucosed‐6‐phosphate, and NADP+‐linked isocitric dehydrogenases was higher in the melanoma than in the ependymoblastoma. β‐Glucuronidase levels were similar in these two neoplasms. It is suggested that the relatively high levels of several NADP+‐linked enzymes in the ependymoblastoma may be related to increased capacity for lipid synthesis.
FATTY ACID AND FATTY ALDEHYDE COMPOSITION OF GLIAL CELL LIPIDS ISOLATED FROM BOVINE WHITE MATTER
Authors: Fewster Mona. E. , Mead J. F.
Published: October 2006

Abstract— Glial cells were isolated from bovine white matter by differential centrifugation. The fatty aldehyde and fatty acid compositions of ethanolamine glycerophosphatides (EGP), serine glycerophosphatides (SGP) and choline glycerophosphatides (CGP) were determined by gas‐liquid chromatography. The fatty acid compositions of the sphingo‐lipids including sphingomyelin, cerebroside and cerebroside sulphate, and of minor lipid components including cholesterol esters and triglycerides, were also determined by gas‐liquid chromatography. The relative proportions correlated closely with the results obtained by O'Brien and Sampson (1965b) for adult human brain. The fatty aldehyde compositions of the glycerophosphatides were more closely related to the corresponding fatty acid compositions of the plasma membrane than of the mitochondria. Long‐chain fatty acids (19–26 carbon atoms) were detected in sphingomyelin, cerebroside and cerebroside sulphate; this indicates that chain‐elongation beyond C18 occurs in the glial cells.
THE UPTAKE OF [3H]GABA BY SLICES OF RAT CEREBRAL CORTEX
Authors: Iversen L. L. , Neal M. J.
Published: October 2006

—A rapid accumulation of [3H]GABA occurs in slices of rat cerebral cortex incubated at 25° or 37° in a medium containing [3H]GABA. Tissue medium ratios of almost 100:1 are attained after a 60 min incubation at 25°. At the same temperature no labelled metabolites of GABA were found in the tissue or the medium. The process responsible for [3H]GABA uptake has many of the properties of an active transport mechanism: it is temperature sensitive, requires the presence of sodium ions in the external medium, is inhibited by dinitrophenol and ouabain, and shows saturation kinetics. The estimated Km value for GABA is 2·2 × 10−5m, and Vmax is 0·115 μmoles/min/g cortex. There is only negligible efflux of the accumulated [3H]GABA when cortical slices are exposed to a GABA‐free medium. [3H]GABA uptake was not affected by the presence of large molar excesses of glycine, l‐glutamic acid, l‐aspartic acid, or β‐aminobutyrate, but was inhibited in the presence of l‐alanine, l‐histidine, β‐hydroxy‐GABA and β‐guanidinopropionate. It is suggested that the GABA uptake system may represent a possible mechanism for the inactivation of GABA or some related substance at inhibitory synapses in the cortex.
TRANSPORT OF NORADRENALINE IN SYMPATHETIC NERVES AND THE EFFECT OF NERVE IMPULSES ON ITS CONTRIBUTION TO TRANSMITTER STORES
Authors: Geffen L. B. , Rush R. A.
Published: October 2006

Abstract— —A study has been made of the contribution of noradrenaline transport along sympathetic nerves to their terminal stores of transmitter by ligating the splenic nerves of the cat, and measuring both the noradrenaline that accumulates above the constriction, and the noradrenaline content of the spleen. The biochemical estimations were supplemented by fluorescence histochemistry. The effect of abolishing efferent impulses in the splenic nerves was examined by cutting their preganglionic nerve supply.

The proximo‐distal flow rate for noradrenaline was calculated as 1.4‐3.3 mm/hr assuming that all the noradrenaline that accumulates is derived from the cell bodies in the ganglion without net addition or loss in the axons. The process was not dependent on impulse traffic in the nerves, since decentralization did not significantly effect the accumulation. The amount of noradrenaline arrested by the constriction in 24 hr was only 1 per cent of the stores in the terminals of those nerves, and consequently no change was detected in the spleen's noradrenaline content as a result of constricting its nerve supply.

In the presence of an intact reflex pathway to the spleen, the stress of the operative procedure produced a marked constriction of the spleen, and depletion of its noradrenaline content. These changes could be prevented either by section of the preganglionic splanchnic nerves, or by ligation of the splenic nerves, thereby blocking the conduction of efferent nerve impulses.

The evidence favours a proximo‐distal flow of noradrenaline in sympathetic nerves, independent of nerve impulses, which makes, however, a negligible quantitative contribution to the terminal stores of transmitter.