bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and phase behavior of nematic liquid‐crystalline elastomers derived from smectic crosslinking agent
Authors: Jia Ying‐Gang , Zhang Bao‐Yan , He Xiao‐Zhi , Ning Jia‐Zun
Published: August 2005

A mesogenic crosslinking agent M‐1 was synthesized to minimize the perturbations of nonmesogenic crosslinking agent for liquid‐crystalline elastomers. The synthesis of side‐chain liquid‐crystalline elastomers containing a rigid mesogenic crosslinking agent M‐1 and a nematic monomer M‐2 was described by a one‐step hydrosilylation reaction. The chemical structures of the obtained monomers and network polymers were confirmed by Fourier transform infrared and 1H‐NMR spectroscopy. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry, polarizing optical microscopy, and X‐ray diffraction measurements. The influence of the crosslinking units on the phase behavior was discussed. The liquid‐crystalline elastomers containing less than 15 mol % of the crosslinking units showed elasticity, reversible phase transition, and threaded texture. The experimental results demonstrated that isotropic temperature and liquid‐crystalline range of polymers P‐1–P‐7 decreased a little as the concentration of crosslinking agent M‐1 increased, and the use of mesomorphic crosslinking agent M‐1 promotes the arrangement of liquid‐crystalline units from P‐1 to P‐5. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1712–1719, 2005
Effect of concentrated sulfuric acid and nitroethane on insoluble residues in acetylating medium of cellulose acetate prepared from low grade pulps
Authors: Shashidhara G. M. , Guruprasad K. H.
Published: August 2005

Cellulose acetate was prepared from locally available low grade pulps containing α‐cellulose in the range of 79–94%. The chemical and spectroscopic characterization confirmed the acetylation of all the cellulosic sources studied in the work. The effect of concentrated sulfuric acid as a catalyst and nitroethane as a solvent in the acetylation medium in reducing the insoluble residues was studied. The gravimetric analysis has indicated that these reagents reduce the insoluble residues. This was further confirmed by the optical microscopic photographs. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1765–1771, 2005
Synthesis and Reactions of Some New Substituted Pyridine and Pyrimidine Derivatives as Analgesic, Anticonvulsant and Antiparkinsonian Agents
Authors: Amr Abd El‐Galil E. , Sayed Hayam H. , Abdulla Mohamed M.
Published: August 2005

A series of substituted pyridine and pyrimidine derivatives were synthesized as analgesic, anti convulsant, and antiparkinsonian agents by using compounds 1, 2, and 9 as starting materials. Pyr idino‐imide derivative 3 was prepared by condensation of 1 with tetrachlorophthalic anhydride and compounds 4 and 5 were also obtained by reaction of compound 1 with 1,2,4,5‐benzene‐tetra carboxylic dianhydride and 1,4,5,8‐naphthalenetetracarboxylic dianhydride, respectively. Similarly, compound 2 was reacted with previous anhydrides to afford the corresponding imide 6 and bis‐imide derivatives 7 and 8, respectively. Bis‐arylmethylene derivatives 9 were treated with hydrogen peroxide to afford the corresponding bis‐oxiranocycloalkanone derivatives 10, which condensed with thiourea to give the corresponding thioxopyrimidine derivatives 11. Treatment of compound 11 with chloroacetic acid in the presence of anhydrous sodium acetate afforded the corresponding thiazolopyrim idine derivative 12 which condensed with aromatic aldehydes in acetic acid/acetic anhydride to give arylmethylene derivative 13. Also, compounds 13 could be prepared by reaction of compounds 11 with chloroacetic acid, aromatic aldehydes, and sodium acetate in a mixture of acetic acid and acetic anhydride. The pharmacological screening showed that many of these obtained compounds have good analgesic, anticonvulsant, and antiparkinsonian activities comparable to Valdecoxib, Carbamazepine, and Benzatropine as reference drugs.
Secondary conformation of short lysine‐ and leucine‐rich peptides assessed by optical spectroscopies: Effect of chain length, concentration, solvent, and time
Authors: Hernández Belén , Boukhalfa‐Heniche F.‐Z. , Seksek Olivier , Coïc Yves‐Marie , Ghomi Mahmoud
Published: August 2005

Solution secondary structures of three synthetic cationic peptides, currently used in antisense oligonucleotide delivery into living cells, have been analyzed by means of circular dichroism (CD) and Raman scattering in different buffers as a function of concentration and time. All three peptides are of minimalist conception, i.e., formed by only two types of amino acids (leucine: L and lysine: K). Two of these peptides contain 15 aminoacids: Nter‐ KLLKLLLKLLLKLLK (L10K5), Nter‐KLKLKLKLKLKLKLK (L7K8), and the third one has only 9 residues: Nter‐KLKLKLKLK (L4K5). The conformational behavior of the 15‐mers in pure water differs considerably one from another. Although both of them are initially disordered in the 50–350 μM range, L10K5gradually undergoes a disordered toα‐helix transition for molecular concentrations above 100 μM. In all other solvents used, L10K5adopts a stableα‐helical conformation. In methanol and methanol/Tris mixture, nonnativeα‐helices can be induced in both KL‐alternating peptides, i.e., L7K8and L4K5. However, in major cases and with a time delay depending on peptide concentration,β‐like structures can be gradually formed in both solutions. In PBS and methanol/PBS mixture, the tendency for L7K8and L4K5is to form structures belonging toβ‐family. A discussion has been undertaken on the effect of counterions as well as their nature in the stabilization of ordered structures in both KL‐alternating peptides. © 2005 Wiley Periodicals, Inc. Biopolymers 81: 8–19, 2006

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Effect of vitamins C and E on oxidative processes in human erythrocytes
Authors: Claro Ligia Maria , Leonart Maria Suely Soares , Comar Samuel Ricardo , do Nascimento Aguinaldo José
Published: August 2005

The oxidative action of 1 mmol l−1 phenylhydrazine hydrochloride (PH) was studied on human erythrocytes treated with the antioxidants vitamin C (vit. C) and vitamin E (vit. E). The erythrocytes were resuspended in PBS to obtain 35% cell packed volume, and then submitted to the oxidative action of PH for 20 min, with or without previous incubation for 60 min with vit. C or vit. E. Heinz bodies and methemoglobin formation by PH were inhibited in the presence of vit. C. At the concentration of 90 mmol l−1, vit. C, not only seemed to lose its antioxidant effect, but it also promoted an increase in methemoglobin formation. Vit. C (0.5–80 mmol l−1) did not protect against GSH depletion by PH. Vit. C alone produced insignificant hemolysis, but, in the presence of PH, the hemolysis indices were more accentuated. Heinz body formation by PH was inhibited in the presence of vit. E. Formation of methemoglobin induced by PH was decreased by vit. E (0.1–2 mmol l−1), although vit. E (3–80 mmol l−1) did not lower the concentration of methemoglobin and did not lead to the recovery of the GSH depleted by PH. The results obtained suggest that vit. C and vit. E contribute to the decrease in oxidative stress caused by PH. Copyright © 2005 John Wiley & Sons, Ltd.
No association between methylenetetrahydrofolate reductase C677T polymorphism and breast cancer
Authors: Hekim Nezih , Ergen Arzu , Yaylım İlhan , Yılmaz Hülya , Zeybek Ümit , Öztürk Oğuz , İsbir Turgay
Published: August 2005

Methylenetetrahydrofolate reductase (MTHFR) is an enzyme (EC 1.5.1.20), that reduces 5,10‐methylenetetrahydrofolate to 5‐methyltetrahydrofolate, a carbon donor for the homocysteine to methionine conversion. MTHFR is a keyenzyme that regulates folate metabolism which has an important role in DNA synthesis, DNA repair and methylation.

The association between MTHFR C677T polymorphism and breast cancer has been investigated in several previous studies. Some researchers have shown an association between C677T polymorphism and breast cancer, but not all researchers found this association however.

This study was designed to investigate, in the Turkish population, the association of MTHFR C677T polymorphism and breast cancer. Forty women patients with breast cancer and 68 healthy women were included in the study. MTHFR gene polymorphism was determined by the PCR‐RFLP method. SPSS 10.0 for windows was used to determine statistical significance.

No differences were observed in the distribution of MTHFR genotypes or allele frequencies in the cases versus the controls. It was found that the frequencies of MTHFR polymorphism were 55%, 40%, 5% for CC, CT, TT genotype in patients and 56%, 38%, 6% in healthy controls respectively. Furthermore, association was observed among family history, metastatic risk and MTHFR genotypes in patients.

Our data fail to support a relationship between MTHFR C677T and the risk for breast cancer. It may be that there are ethnic differences in terms of this relationship. Copyright © 2005 John Wiley & Sons, Ltd.
Haloacyl Complexes of Boron, [(CF3)3BC(O)Hal]−(Hal=F, Cl, Br, I)
Authors: Finze Maik , Bernhardt Eduard , Willner Helge , Lehmann Christian W.
Published: August 2005

The haloacyltris(trifluoromethyl)borate anions [(CF3)3BC(O)Hal]−(Hal=F, Cl, Br, I) have been synthesized by reacting (CF3)3BCO with either MHal (M=K, Cs; Hal=F) in SO2or MHal (M=[nBu4N]+, [Et4N]+, [Ph4P]+; Hal=Cl, Br, I) in dichloromethane. Metathesis reactions of the fluoroacyl complex with Me3SiHal (Hal=Cl, Br, I) led to the formation of its higher homologues. The thermal stabilities of the haloacyltris(trifluoromethyl)borates decrease from the fluorine to the iodine derivative. The chemical reactivities decrease in the same order as demonstrated by a series of selected reactions. The new [(CF3)3BC(O)Hal]−(Hal=F, Cl, Br) salts are used as starting materials in the syntheses of novel compounds that contain the (CF3)3BC fragment. All borate anions [(CF3)3BC(O)Hal]−(Hal=F, Cl, Br, I) have been characterized by multinuclear NMR spectroscopy (11B,13C,17O,19F) and vibrational spectroscopy. [PPh4][(CF3)3BC(O)Br] crystallizes in the monoclinic space groupP2/c(no. 13) and the bond parameters are compared with those of (CF3)3BCO and K[(CF3)3BC(O)F]. The interpretation of the spectroscopic and structural data are supported by DFT calculations [B3LYP/6‐311+G(d)].
Molecular Scaffold for the Construction of Three‐Armed and Cage‐Like Receptors
Authors: Haberhauer Gebhard , Oeser Thomas , Rominger Frank
Published: August 2005

An efficient procedure was developed for the synthesis of the C3‐symmetric molecular scaffold 2. The latter can easily be converted by a single step into either the three‐armed receptors 11–16 or the cage‐like receptor 17. X‐ray structures were obtained for 2, 11, and 16, which are discussed in regard to their aptitude as receptor platforms. The interaction of the three‐armed receptors 12–16 and the cage‐like receptor 17 with phloroglucinol was investigated. In accordance with the conclusions obtained from molecular modeling and X‐ray crystallographic studies on the host–guest complexes, the three‐armed bipyridine receptor 16 exhibits, due to its induced fit, a larger association constant toward phloroglucinol than the cage 17. This new receptor system shows all of the positive features characteristic of 2,4,6‐trialkylbenzene receptor systems, such as conformational control by steric gearing, ready availability, and versatility in derivatization. These attributes, combined with the advantageous size of the components, allows this system to be readily tailored to provide receptors for larger, biologically important molecules.
Guest‐Induced Supramolecular Isomerism in Inclusion Complexes of T‐Shaped Host 4,4‐Bis(4′‐hydroxyphenyl)cyclohexanone
Authors: Aitipamula Srinivasulu , Nangia Ashwini
Published: August 2005

The T‐shaped host molecule 4,4‐bis(4′‐hydroxyphenyl)cyclohexanone (1) has an equatorial phenol group and a cyclohexanone group along the arms and an axial phenol ring as the stem. The equatorial phenyl ring adopts a “shut” or “open” conformation, like a windowpane, depending on the size of the guest (phenol or o/m‐cresol), for the rectangular voids of the hydrogen‐bonded ladder host framework. The adaptable cavity of host 1 expands to 11×15–18 Å through the inclusion of water with the larger cresol and halophenol guests (o‐cresol, m‐cresol, o‐chlorophenol, and m‐bromophenol) compared with a size of 10×13 Å for phenol and aniline inclusion. The ladder host framework of 1 is chiral (P21) with phenol, whereas the inclusion of isosteric o‐ and m‐fluorophenol results in a novel polar brick‐wall assembly (7×11 Å voids) as a result of auxiliary CH⋅⋅⋅F interactions. The conformational flexibility of strong OH⋅⋅⋅O hydrogen‐bonding groups (host 1, phenol guest), the role of guest size (phenol versus cresol), and weak but specific intermolecular interactions (herringbone T‐motif, CH⋅⋅⋅F interactions) drive the crystallization of T‐host 1 towards 1D ladder and 2D brick‐wall structures, that is, supramolecular isomerism. Host 1 exhibits selectivity for the inclusion of aniline in preference to phenol as confirmed by X‐ray diffraction, 1H NMR spectroscopy, and thermogravimetry‐infrared (TG‐IR) analysis. The Tonset value (140 °C) of aniline in the TGA is higher than those of phenol and the higher‐boiling cresol guests (Tonset=90–110 °C) because the former structure has more OH⋅⋅⋅N/NH⋅⋅⋅O hydrogen bonds than the clathrate of 1 with phenol which has OH⋅⋅⋅O hydrogen bonds. Guest‐binding selectivity for same‐sized phenol/aniline molecules as a result of differences in hydrogen‐bonding motifs is a notable property of host 1. Host–guest clathrates of 1 provide an example of spontaneous chirality evolution during crystallization and a two‐in‐one host–guest crystal (phenol and aniline), and show how weak CH⋅⋅⋅F interactions (o‐ and m‐fluorophenol) can change the molecular arrangement in strongly hydrogen‐bonded crystal structures.
Use of Allyl, 2‐Tetrahydrofuryl, and 2‐Tetrahydropyranyl Ethers as Useful C3‐, C4‐, and C5‐Carbon Sources: Palladium‐Catalyzed Allylation of Aldehydes
Authors: Shimizu Masamichi , Kimura Masanari , Tamaru Yoshinao
Published: August 2005

Palladium–diethylzinc or palladium–triethylborane catalytically promotes self‐allylation of 2‐(allyloxy)tetrahydrofurans, 2‐(allyloxy)tetrahydropyrans, and their hydroxy derivatives on the rings (ribose, glucose, mannose, deoxyribose, deoxyglucose). All the reactions proceed at room temperature and provide polyhydroxyl products, sharing a structural motif of a homoallyl alcohol, in good to excellent yields with high levels of stereoselectivity. Useful C3‐unit elongation, which makes the best use of an allyl ether as a protecting group and a nucleophilic allylation agent, is demonstrated. Mechanisms for the umpolung reaction (of an allyl ether into an allylic anion) and stereoselectivity associated with allylation of aldehydes are discussed.
Self‐Assembled Fluorescent Chemosensors
Authors: Mancin Fabrizio , Rampazzo Enrico , Tecilla Paolo , Tonellato Umberto
Published: August 2005

Self‐assembling and self‐organizing methodologies are powerful tools for the “bottom‐up” approach for the realization of complex structure with functional properties. Recently, this concept has been extended to the design of fluorescent chemosensors providing new exciting potentialities for the development of innovative sensing systems. This Concept Article deals mainly with this new approach and discusses its evolution, applications, and limitations.
Frontal Copolymerization Synthesis and Property Characterization of Starch‐graft‐poly(acrylic acid) Hydrogels
Authors: Yan Qing‐Zhi , Zhang Wen‐Feng , Lu Guo‐Dong , Su Xin‐Tai , Ge Chang‐Chun
Published: August 2005

Recently, a considerable amount of research has centered on uniquely structured polymers synthesized through self‐propagating frontal polymerization. The obtained polymer materials have better features than those obtained by using the classical batch route. The additional advantages are short reaction times and low cost. This work describes the first frontal polymerization synthesis of a graft copolymer superabsorbent hydrogel of acrylic acid onto starch at high monomer and initiator concentration. The effects of varying the relative amounts of the reaction components on the most relevant parameters relating to frontal polymerization were explored. The front velocity dependence on initiator concentration could be fit to a power function. The temperature profiles were found to be very sharp with a maximum temperature below 150 °C, which was responsible for high monomer conversion. The ultimate properties of the product appear to depend on the polymerization front velocity and the temperature. The high‐temperature and rapid temperature increase at the polymerization front led to products with interconnected porous structures caused by the evaporation of water. So, a fast‐swelling, highly absorbing hydrogel with respect to batch polymerization was obtained.
A phase II trial of temozolomide as a 6‐week, continuous, oral schedule in patients with advanced soft tissue sarcoma
Authors: Garcia del Muro Xavier , Lopez‐Pousa Antonio , Martin Javier , Buesa Jose M. , Martinez‐Trufero Javier , Casado Antonio , Poveda Andres , Cruz Josefina , Bover Isabel , Maurel Joan ,   for the Spanish Group for Research on Sarcomas
Published: August 2005

BACKGROUND

The objective of this study was to evaluate the activity and toxicity of temozolomide given as an extended schedule in patients with advanced sarcoma.

METHODS

Forty‐nine patients with pretreated soft tissue sarcoma (the STS arm) and 18 patients with previously untreated gastrointestinal stromal tumor (the GIST arm) were enrolled onto a 2‐arm, multicenter, Phase II study between November 1999 and July 2001. Temozolomide was administered on a 6‐week, continuous, oral schedule at a dose of 75 mg/m2 per day in 41 patients and, after an amendment, at a dose of 100 mg/m2 per day in 22 patients.

RESULTS

Among 45 eligible patients in the STS arm, there were 7 partial responses, for an overall response rate of 15.5% (95% confidence interval [95% CI], 5–26%). Responses were seen in 5 of 11 patients who had gynecologic leiomyosarcoma. The median response duration was 12.5 months (range, 3.9–58.0 mos). In 4 patients, response lasted > 1 year, and 2 of those patients remained progression free for > 3 years. The median time to progression was 2.2 months (95% CI, 1.8–2.5 mos), and the median overall survival was 8.1 months (95% CI, 5.6–10.6 mos). Progression‐free survival rates at 3 months and 6 months were 39.5% and 26%, respectively. In the GIST arm, no responses were noted. Grade 3–4 granulocytopenia, thrombocytopenia, and anemia were observed in 6 patients, 5 patients, and 7 patients, respectively. The most common nonhematologic toxicities were emesis and fatigue.

CONCLUSIONS

Temozolomide at the extended schedule was tolerated well and had activity in patients with pretreated soft tissue sarcomas, and especially among patients with gynecologic leiomyosarcoma. Cancer 2005. © 2005 American Cancer Society.
WT1 and WT1‐AS genes are inactivated by promoter methylation in ovarian clear cell adenocarcinoma
Authors: Kaneuchi Masanori , Sasaki Masahiro , Tanaka Yuichiro , Shiina Hiroaki , Yamada Hideto , Yamamoto Ritsu , Sakuragi Noriaki , Enokida Hideki , Verma Mukesh , Dahiya Rajvir
Published: August 2005

BACKGROUND

Ovarian clear cell adenocarcinoma is associated with one of the poorest prognoses among human epithelial ovarian cancers. The authors hypothesized that Wilms tumor suppressor 1 gene (WT1) sense and antisense (WT1‐AS) expression and their promoter methylation status could characterize ovarian clear cell adenocarcinoma from ovarian serous adenocarcinoma.

METHODS

To test this hypothesis, ovarian cancer cell lines and 42 cancer tissues (17 clear cell and 25 serous adenocarcinoma) were analyzed for expression and methylation of WT1 and WT1‐AS genes.

RESULTS

These experiments demonstrated that all serous adenocarcinoma tissues expressed both WT1 and WT1‐AS genes, although expression of these genes was lacking in clear cell adenocarcinoma. The WT1 and WT1‐AS promoter were significantly methylated in clear cell adenocarcinoma (88.2% and 88.2%, respectively) compared with serous adenocarcinoma (24.0% and 20.0%, respectively). Significant correlation between methylation and mRNA expression status was observed for each gene. Also in agreement with these data, WT1 and WT1‐AS negative ovarian cancer cell lines reexpressed these genes after treatment with the demethylating agent, 5‐aza‐2′‐deoxycytidine.

CONCLUSIONS

The current study shows that CpG hypermethylation is an important mechanism of WT1 and WT1‐AS gene inactivation in ovarian clear cell adenocarcinoma. This is the first report that has demonstrated differential expression and methylation of WT1‐AS in ovarian clear cell and serous adenocarcinomas. This study presents new molecular characterizations between these two types of adenocarcinoma and may provide insight as to why clear cell adenocarcinoma has a poorer prognosis than serous adenocarcinoma of the ovary. Cancer 2005. © 2005 American Cancer Society.
Fiber connections of the anterior preglomerular nucleus in cyprinids with notes on telencephalic connections of the preglomerular complex
Authors: Yamamoto Naoyuki , Ito Hironobu
Published: August 2005

Fiber connections of the anterior preglomerular nucleus (PGa) were studied in carp and goldfish by tracer injection experiments to the nucleus and telencephalon. The PGa received fibers from the central nucleus of semicircular torus, perilemniscular nucleus, anterior tuberal nucleus, and medial pretoral nucleus, all of which are presumed auditory structures. The PGa projected to the dorsal (dDm) and ventral (vDm) regions of medial part of dorsal telencephalic area. The caudomedial region of lateral preglomerular nucleus (PGl) and medial zone of medial preglomerular nucleus (PGm), which also receive auditory toral fibers, projected to the same telencephalic regions as did PGa. These preglomerular structures and the PGa also received in common descending fibers from a rostromedial portion of dDm. The PGa also received fibers from the parvocellular and magnocellular preoptic nuclei, and suprachiasmatic nucleus and projected to the anterior tuberal nucleus and medial inferior lobe, suggesting neurohormonal and circadian control on the PGa and auditory influences on hypothalamic functions. Of other diencephalic nuclei that receive auditory toral fibers, only small numbers of neurons were labeled in the central posterior thalamic nucleus and anterior tuberal nucleus even after large injections to the dorsal telencephalic area. Thus, the PGa and closely related preglomerular regions, not the dorsal thalamus, appear to constitute the major auditory relay station to the dorsal telencephalic area. The rostrolateral region of PGl, rostral and lateral zones of PGm, commissural preglomerular nucleus, and preglomerular tertiary gustatory nucleus, which do not receive auditory toral fibers, also projected to the dorsal telencephalic area. J. Comp. Neurol. 491:212–233, 2005. © 2005 Wiley‐Liss, Inc.
Mapping auditory core, lateral belt, and parabelt cortices in the human superior temporal gyrus
Authors: Sweet Robert A. , Dorph‐Petersen Karl‐Anton , Lewis David A.
Published: August 2005

The goal of the present study was to determine whether the architectonic criteria used to identify the core, lateral belt, and parabelt auditory cortices in macaque monkeys (Macaca fascicularis) could be used to identify homologous regions in humans (Homo sapiens). Current evidence indicates that auditory cortex in humans, as in monkeys, is located on the superior temporal gyrus (STG), and is functionally and structurally altered in illnesses such as schizophrenia and Alzheimer's disease. In this study, we used serial sets of adjacent sections processed for Nissl substance, acetylcholinesterase, and parvalbumin to identify the distinguishing cyto‐ and chemoarchitectonic features of the core, lateral belt, and parabelt in monkey. These criteria were evaluated in postmortem tissue from a human subject, leading to the identification of additional criteria specific to human. The criteria were validated in an additional set of eight human subjects. Regions were delineated and their volumes estimated using the Cavalieri method in these subjects, and the sources of methodologic contribution to variability of the estimates was assessed. Serial reconstructions of the auditory cortex in humans were made showing the location of the lateral belt and parabelt with respect to gross anatomical landmarks. Architectonic criteria for the core, lateral belt, and parabelt were readily adapted from monkey to human. Additionally, we found evidence for an architectonic subdivision within the parabelt, present in both species. Variability of regional volume estimates was readily constrained using a multifaceted approach to reduce potential sources of variability in regional delineation. J. Comp. Neurol. 491:270–289, 2005. © 2005 Wiley‐Liss, Inc.
Phylogenetic investigation of Dogiel's pericellular nests and Cajal's initial glomeruli in the dorsal root ganglion
Authors: Matsuda Seiji , Kobayashi Naoto , Terashita Takehiro , Shimokawa Tetsuya , Shigemoto Kazuhiro , Mominoki Katsumi , Wakisaka Hiroyuki , Saito Shouichiro , Miyawaki Kyoujy , Saito Kyoko , Kushihata Fumiki , Chen Jie , Gao Shuang‐Yan , Li Chun‐Yu , Wang Min , Fujiwara Takashi
Published: August 2005

Cajal's initial glomeruli (IG) and Dogiel's pericellular nests (PCNs) were first described from methylene blue preparations of healthy animal tissues around the beginning of the last century. Since that time, although many reports have been published concerning these structures, few have focused on their development and phylogeny in healthy animals. The aim of this study was to examine the phylogenetic development of the sensory neurons in Cajal's IG (also called axonal glomeruli) and Dogiel's PCNs in the dorsal root ganglion (DRG) of the healthy adult frog, chick, rat, and rabbit. The three‐dimensional architecture of the neurons was observed in ganglia by scanning electron microscopy after removal of the connective tissue. The neurons in the DRG of fish are known to be bipolar, but DRG neurons in the species examined here were found to be pseudounipolar, with single stem processes. The proportion of neurons having IG or PCNs increased with increasing phylogenetic complexity in the species examined here. Cajal's initial glomeruli, the convolution of the stem process near the parent cell body: In frogs, the ganglia were small and the neuronal stem processes were very short and straight. In chicks, the stem processes were longer; sometimes very long, tortuous processes were observed. However, no neurons with typical IG were observed in either species. Typical IG were observed in rats and rabbits; their occurrence was much more frequent in rabbits. Pseudounipolarization, i.e., the transition from bipolar to pseudounipolar neurons, is thought to save space, limit the length of neuronal processes, and reduce conduction time. However, an explanation of the evolutionary advantage of the IG, which is formed by the excessive prolongation of the stem process, remains elusive. The cytological and electrophysiological importance of IG has been discussed. Dogiel's pericellular nests (PCNs), which resemble balls of yarn made of thin unmyelinated nerve fibers around DRG neurons, have been observed in the DRG of rats and rabbits, but not in frogs or chicks. This interesting structure shows not only ontogenetic development in healthy animals but also phylogenetic development among species. The nerve fibers in the PCNs were less than 1.2 μm in diameter and had some varicosities. An immunohistochemical study using anti‐tyrosine hydroxylase (TH) antibody revealed that some PCNs contain TH‐positive nerve fibers and varicosities. Such TH‐positive PCNs disappear after sympathectomy. These results suggest that the PCNs are made up of autonomic nerve fibers. J. Comp. Neurol. 491:234–245, 2005. © 2005 Wiley‐Liss, Inc.
Changes in systemic type 1 and type 2 immunity in normal pregnancy and pre‐eclampsia may be mediated by natural killer cells
Authors: Borzychowski Angela M. , Croy B. Anne , Chan W. Ling , Redman Christopher W. G. , Sargent Ian L.
Published: August 2005

A bias of T cell immunity towards type 2 (Th2) is thought to be critical for normal pregnancy. Pathological pregnancies, such as pre‐eclampsia, are characterised by cell‐mediated (Th1) immune dominance. The Th1/Th2 paradigm, however, is too simplistic. Normal pregnancy is associated with a systemic inflammatory response which increases throughout gestation. This inflammatory response is exaggerated in pre‐eclampsia, a syndrome of the third trimester. T helper (Th) cells are considered the primary mediators of these altered immune responses, and other T cells, i.e. T cytotoxic (Tc) cells, and lymphocytes of the innate immune system, i.e. natural killer (NK) and NKT cells, have been largely disregarded. In this study, we have used novel pan type 1 (IL‐18 receptor) and pan type 2 (ST2L) lymphocyte function markers in four‐colour flow cytometry to broadly characterise peripheral blood lymphocyte populations from non‐pregnant, normal pregnant and pre‐eclamptic women. There were no changes in the Th1/Th2 or Tc1/Tc2 cell ratios between the three groups; however, the NK1/NK2 and NKT1/NKT2 cell ratios were significantly decreased in normal pregnancy compared with non‐pregnant (p <0.001 and p <0.01, respectively) and pre‐eclamptic women (p <0.05). These results confirm that immunoregulation occurs in pregnancy, but suggest a dominant role of the innate rather than the adaptive immune system.
High frequencies of functionally impaired cytokeratin 18‐specific CD8+ T cells in healthy HLA‐A2+ donors
Authors: Walter Steffen , Bioley Gilles , Bühring Hans‐Jörg , Koch Sven , Wernet Dorothee , Zippelius Alfred , Pawelec Graham , Romero Pedro , Stevanović Stefan , Rammensee Hans‐Georg , Gouttefangeas Cécile
Published: August 2005

Combining cell surface phenotyping with functional analysis, human CD8+ T cells have been divided into several subsets which are being studied extensively in diverse physiological situations, such as viral infection, cancer and ageing. In particular, so‐called terminally differentiated effector cells possess a CD45RA+CCR7–CD27–CD28– phenotype, contain perforin and, in different models, have been shown to exert direct ex vivo killing and to release interleukins upon both antigen‐nonspecific and ‐specific stimulation. Using HLA class I multimers, we have identified a high frequency of peripheral CD8+ T cells that recognize a peptide derived from the self protein cytokeratin 18 presented by the HLA‐A*0201 molecule. These cells can be detected in approximately 15% of the HLA‐A2‐positive healthy donors tested. A detailed analysis revealed that they must have divided extensively in vivo, have an effector cell phenotype and express various natural killer cell‐associated receptors. Interestingly, however, they remained unresponsive to antigen‐specific stimulation in vitro in terms of cytotoxicity and cytokine secretion. Thus, cytokeratin 18‐specific cells constitute a frequently encountered, new CD8+ T lymphocyte subpopulation without classical effector status and with so far unknown function.
Specific ICAM‐3 grabbing nonintegrin‐related 1 (SIGNR1) expressed by marginal zone macrophages is essential for defense against pulmonary Streptococcuspneumoniae infection
Authors: Koppel Estella A. , Wieland Catharina W. , van den Berg Venice C. M. , Litjens Manja , Florquin Sandrine , van Kooyk Yvette , van der Poll Tom , Geijtenbeek Teunis B. H.
Published: August 2005

The dendritic cell‐specific ICAM‐3‐grabbing nonintegrin (DC‐SIGN) homolog, SIGN‐related 1 (SIGNR1) is a pathogen receptor expressed by splenic marginal zone and peritoneal macrophages, and is essential for clearance of Streptococcus pneumoniae by phagocytosis after intraperitoneal infection. Here, we identified an important in vivo function for SIGNR1 in S. pneumonia infection induced via its natural entrance route. Upon intranasal infection with S. pneumoniae, SIGNR1‐deficient mice did not clear bacteria from lung and blood, and displayed severely enhanced inflammatory parameters compared to the wild‐type mice. However, SIGNR1 is not expressed by alveolar macrophages, suggesting that another mechanism than a decrease in phagocytosis is responsible for this difference. Natural anti‐phosphorylcholine IgM produced by marginal zone B cells is essential for protection against infection with S. pneumoniae. Strikingly, during infection, SIGNR1‐deficient mice failed to produce a rapid anti‐phosphorylcholine IgM response. Marginal zone macrophages have been suggested to capture antigens for presentation to marginal zone B cells. We demonstrate that marginal zone macrophages from SIGNR1‐deficient mice in contrast to wild‐type mice are not able to capture pneumococci from blood, suggesting that SIGNR1 on marginal zone macrophages captures S. pneumoniae for antigen presentation to and activation of marginal zone B cells, resulting in an anti‐phosphorylcholine IgM response.
Control of murine gammaherpesvirus infection is independent of NK cells
Authors: Usherwood Edward J. , Meadows Sarah K. , Crist Sarah G. , Bellfy Sarah C. , Sentman Charles L.
Published: August 2005

Numerous studies have shown that NK cells are important in controlling the early stages of infection with alpha‐ or betaherpesviruses. In contrast, little is known about the impact of NK cells on gammaherpesvirus infections. We tested mice with defects in NK cells for their ability to resist murine gammaherpesvirus (MHV‐68) infection. The depletion of NK cells had no effect on the control of the acute or latent stages of the infection. In addition, transgenic mice deficient in NK cells controlled the infection in a comparable manner to wild‐type mice. We also showed that the antiviral CD8 T cell response was unaffected by the presence or absence NK cells. We conclude that NK cells contribute little to the control of MHV‐68 infection, and therefore, NK cells are not essential for controlling all herpesvirus infections.
Nanoscaled Sn and Pb Particles Aligned in Al2O3 Tubes Obtained from Molecular Precursors
Authors: Veith Michael , Frères Jacqueline , König Peter , Schütt Oliver , Huch Volker , Blin Joel
Published: August 2005

Tin and lead nanoparticles and metal sponges were prepared by reducing Me2Si(NtBu)2Sn (7) and Me2Si(NtBu)2Pb (9) with [H2AlOtBu] (3), [HAl(OtBu)2] (13), [H2AlOSiMe2tBu] (8), and [(Me2tBuSiO)2AlH] (15). Together with dihydrogen and the metals in their elemental state the monomeric compounds [Me2Si(NtBu)2Al(OSiMe2tBu)(THF)] (10) and [Me2Si(NtBu)2Al(OtBu)(THF)] (11) can be obtained, to mention only two examples. Each monomer is stabilized by a THF molecule coordinated to aluminum, which on sublimation loses its donor molecule and dimerizes through Lewis acid–base interactions to the spiro compounds [Me2Si(NtBu)2AlOSiMe2tBu]2 (12) and [Me2Si(NtBu)2AlOtBu]2 (4), respectively. The molecular structures of 10, 11, and 12 were determined by single‐crystal X‐ray diffraction techniques. The reduction of 7 at –115 °C is gradually indicated by a color change of the reaction mixtures from red to dark brown with increasing temperature and depending on the reducing agent used. The tin powders that were obtained were identified as β‐tin using X‐ray powder diffraction techniques and their average crystallite size depends on the polarity of the solvent and hydride used. Under certain conditions metal sponges are formed. Pycnometric measurements were carried out on the tin and lead sponges. These showed almost the known densities for the metals when helium was used whereas significantly smaller ones were measured in water. Porous alumina membranes of different pore diameters were filled with tin and lead particles. Metal nanoparticles were prepared within the tubes of the membranes by reduction of the metal amides in the pores. The infiltration process can be repeated up to ten times increasing the amount of particles within the tubes monitored by SEM. The obtained brown or black membranes were characterized by SEM, EDX, and UV/Vis analysis. The filled membranes show sharp impervious ranges in the UV/Vis spectrum between 270 and 525 nm and could therefore be used as wavelength filters. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Cover Picture: Dithioacetals as Zwitterion Synthons (Eur. J. Org. Chem. 18/2005)
Authors: Luh Tien‐Yau , Lee Chin‐Fa
Published: August 2005

The cover picture shows recent advances in the synthetic applications of the dithioacetal functionality. With the aid of thiophilic organolithium or organocopper reagents, propargylic dithioacetals and related compounds have been shown to be useful for the synthesis of polysubstituted allenes, trisubstituted furans and pyrroles. An extension of this annulation reaction to the bidirectional iterative synthesis of furan‐containing oligoaryls and to cyclophane synthesis is described. Alternatively, convergent synthesis of such oligo aryls from propargylic dithioacetals is briefly discussed. Not only can the carbon–sulfur bonds in dithioacetals be readily displaced by carbon–carbon and/or carbon–heteroatom bonds, but a range of reactions involving polarity inversion in neighboring carbon atoms can also take place. Representative examples are presented in the Microreview by T.‐Y. Luh and C.‐F. Lee on p. 3875 ff.
Using cosmogenic nuclides to contrast rates of erosion and sediment yield in a semi‐arid, arroyo‐dominated landscape, Rio Puerco Basin, New Mexico
Authors: Bierman Paul R. , Reuter Joanna M. , Pavich Milan , Gellis Allen C. , Caffee Marc W. , Larsen Jennifer
Published: August 2005

Analysis of in‐situ‐produced 10Be and 26Al in 52 fluvial sediment samples shows that millennial‐scale rates of erosion vary widely (7 to 366 m Ma−1) through the lithologically and topographically complex Rio Puerco Basin of northern New Mexico. Using isotopic analysis of both headwater and downstream samples, we determined that the semi‐arid, Rio Puerco Basin is eroding, on average, about 100 m Ma−1. This rapid rate of erosion is consistent with estimates made using other techniques and is likely to result from a combination of easily eroded lithologies, sparse vegetation, and monsoon‐dominated rainfall. Data from 331 stream water samples collected by the US Geological Survey between 1960 and 1995 are consistent with basin‐wide, average chemical denudation rates of only about 1·4 m Ma−1; thus, the erosion rates we calculate may be considered rates of sediment generation because physical weathering accounts for almost 99 per cent of mass loss.

The isotopic data reveal that sediment is generally well mixed downstream with the area‐weighted average sediment generation rate for 16 headwater samples (234 ton km−2 a−1 for basin area 170 to 1169 km2) matching well that estimated from a single sample collected far downstream (238 ton km−2 a−1, basin area = 14 225 km2). A series of 15 samples, collected from an arroyo wall and representing deposition through the late Holocene, indicates that 10Be concentration in sediment delivered by the fluvial system has not changed appreciably over the last 1200 years despite at least two cycles of arroyo cutting and filling. Other samples (n = 21) were collected along the drainage network.

Rio Puerco erosion rates scale directly with a variety of metrics describing vegetation, precipitation, and rock erodibility. Using the headwater basins for calibration, the erosion rates for both the downstream samples and also the data set as a whole, are best modelled by considering a combination of relief and vegetation metrics, both of which co‐vary with precipitation and erodibility as inferred from lithology. On average, contemporary sediment yields, determined by monitoring suspended‐sediment discharge, exceed cosmogenically determined millennial‐scale erosion rates by nearly a factor of two. This discrepancy, between short‐term rates of sediment yield and long‐term rates of erosion, suggests that more sediment is currently being exported from the basin than is being produced. Because the failure of incised channel walls and the head cutting of arroyo complexes appear to be the main sources of channel sediment today, this incongruence between rates of sediment supply and sediment yield is likely to be transitory, reflecting the current status of the arroyo cycle and perhaps the influence of current or past land‐use patterns. Copyright © 2005 John Wiley & Sons, Ltd.
Fluvial bedrock incision in the active mountain belt of Taiwan from in situ‐produced cosmogenic nuclides
Authors: Schaller M. , Hovius N. , Willett S. D. , Ivy‐Ochs S. , Synal H.‐A. , Chen M.‐C.
Published: August 2005

The concentration of cosmogenic nuclides in rocks exposed at the Earth's surface is proportional to the total duration of their exposure. This is the basis for bedrock surface exposure dating and has been used to constrain valley lowering rates in the Taroko gorge, eastern Central Range, Taiwan. Taroko gorge contains a uniquely complete geomorphic record of fluvial valley lowering: continuous, fluvially sculpted surfaces are present in the lower 200 m of this marble gorge. Assuming no post‐fluvial erosion of the gorge wall, the concentration of in situ‐produced cosmogenic 36Cl measured in gorge wall marbles reveals exposure ages from 0·2 ka in the active channel to 6·5 ka at 165 m above the present river. These ages imply an average fluvial incision rate of 26 ± 3 mm a−1 throughout the middle and late Holocene. Taking into account lateral gorge wall retreat after initial thalweg lowering would give rise to calculated older exposure ages. Without considering gorge wall retreat, our estimates therefore represent maximum incision rates. Estimated maximum Holocene incision rates are higher than the long‐term exhumation rates derived from fission track dating. The long‐term gorge development governed by tectonic uplift is superimposed by short‐term variations in incision rates caused by climatic or regional tectonic changes. Copyright © 2005 John Wiley & Sons, Ltd.
Episodic incision of the Colorado River in Glen Canyon, Utah
Authors: Garvin Cristofer D. , Hanks Thomas C. , Finkel Robert C. , Heimsath Arjun M.
Published: August 2005

Incision rates of the Colorado River are integral to understanding the development of the Colorado Plateau. Here we calculate episodic incision rates of the Colorado River based on absolute ages of two levels of Quaternary deposits adjacent to Glen Canyon, Utah, along the north flank of Navajo Mountain. Minimum surface ages are determined by a combination of cosmogenic radionuclide surface exposure ages, uranium series and soil‐development formation times. Bedrock incision rates of the Colorado River between c. 500 ka and c. 250 ka, and c. 250 ka to present are c. 0·4 m ka−1 and c. 0·7 m ka−1, respectively. These rates are more than double the rates reported in the Grand Canyon, suggesting that the Colorado River above Lees Ferry is out of equilibrium with the lower section of the river. We also determine incision rates of two tributaries to the Colorado River. Oak Creek and Bridge Creek flow off Navajo Mountain into Glen Canyon from the southeast. Oak Creek and Bridge Creek both have incision rates of c. 0·6 m ka−1 over the past c. 100 ka at points about 9 km away from the main stem of the Colorado River. Copyright © 2005 John Wiley & Sons, Ltd.
Erosion rates driven by channel network incision in the Bolivian Andes
Authors: Safran Elizabeth B. , Bierman Paul R. , Aalto Rolf , Dunne Thomas , Whipple Kelin X. , Caffee Marc
Published: August 2005

The Bolivian Andes flank one of Earth's major topographic features and dominate sediment input into the Amazon Basin. Millennial‐scale erosion rates and dominant controls on erosion patterns in this range are poorly known. To define these patterns, we present 48 erosion rate estimates, derived from analysis of in situ 10Be in quartz‐bearing alluvium collected from the Upper Beni River basin.

Erosion rates, corrected for the non‐uniform distribution of quartz in the sample basins, range from 0·04 mm a−1 to 1·35 mm a−1 and thus integrate over 102–104 years. Mean and modal values are 0·42 (standard deviation: 0·29) and 0·2–0·4 mm a−1 respectively, within the range of long‐term average erosion rates in this area derived from apatite fission track thermochronology (0·1–0·6 mm a−1). Hence, our data do not record any significant variation in erosion rate over the last several million years. Mean and modal short‐term erosion rates for the Andes are an order of magnitude lower than rates in the Ganges River headwaters in the High Himalaya and an order of magnitude greater than rates typical of the European Alps.

In the Upper Beni River region of the Bolivian Andes, short‐term, basin‐averaged erosion rates correlate with normalized channel steepness index, a metric of relative channel gradient corrected for drainage area. Neither normalized channel steepness index nor basin‐averaged erosion rate shows strong correlation with mean basin hillslope gradient or mean basin local relief because many hillslopes in the Upper Beni River region are at threshold values of slope and local relief. Patterns of normalized channel steepness index appear primarily to reflect tectonic patterns and transient adjustment to those patterns by channel networks. Climate and lithology do not appear to exert first‐order controls on patterns of basin‐averaged erosion rates in the Bolivian Andes. Copyright © 2005 John Wiley & Sons, Ltd.
Erosion rates over millennial and decadal timescales at Caspar Creek and Redwood Creek, Northern California Coast Ranges
Authors: Ferrier Ken L. , Kirchner James W. , Finkel Robert C.
Published: August 2005

Comparing millennial‐scale denudation rates from cosmogenic nuclides with decadal‐scale sediment yields can shed light on erosional processes and on the effects of land use on sediment delivery to streams. Detailed measurements of sediment fluxes in the Northern California Coast Ranges at Caspar Creek and Redwood Creek have provided estimates of physical erosion rates since 1963 and 1971, respectively. We used cosmogenic 10Be to measure millennial‐scale denudation rates averaged over 1400–8700 years at six catchments in Caspar Creek and four catchments in Redwood Creek. Our 10Be measurements at Caspar Creek imply denudation rates that are nearly spatially uniform across the entire catchment and average 0·09 ± 0·02 mm a−1. These millennial‐scale rates implied by cosmogenic 10Be are faster than physical erosion rates of 0·005 ± 0·001 mm a−1 to 0·046 ± 0·007 mm a−1 inferred from sediment flux measurements over the past few decades in the same catchments. At Redwood Creek, our cosmogenic 10Be measurements imply millennial‐scale denudation rates that vary across the catchment from 0·14 ± 0·03 mm a−1 to 0·44 ± 0·09 mm a−1, in contrast to physical erosion rates ranging from 0·038 ± 0·011 mm a−1 to 0·48 ± 0·09 mm a−1 derived from sediment flux measurements made over the past few decades at the same catchments. The decadal‐scale and millennial‐scale measurements tend to differ most at the smallest tributaries, but differ by less than a factor of three for the Caspar Creek and Redwood Creek catchments as a whole. These measurements suggest that denudation rates at Caspar Creek are slower than rock uplift rates of 0·3–0·4 mm a−1, implying that Caspar Creek is not in topographic steady state. Copyright © 2005 John Wiley & Sons, Ltd.