bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and In Vitro Evaluation of 2‐Aminoquinazolin‐4(3H)‐one‐Based Inhibitors for tRNA‐Guanine Transglycosylase (TGT)
Authors: Meyer Emmanuel A. , Furler Maya , Diederich François , Brenk Ruth , Klebe Gerhard
Published: June 2004

tRNA‐Guanine transglycosylase (TGT) plays a key role in the post‐transcriptional modification of tRNA. It has been linked with the pathogenicity of shigellae, the causative agents of bacillary dysentery (shigellosis). Here, we report structureactivity relationships (SARs) for a new series of 2‐aminoquinazolin‐4(3H)‐one‐based inhibitors of TGT, resulting from structure‐based design (Fig. 2). Versatile synthetic protocols allow selective functionalization of the 2‐aminoquinazolin‐4(3H)‐one core (Schemes 1–6) with H‐bond‐donor groups in position 6 (for H‐bonding to the C=O group of Leu231) and lipophilic residues in position 8 for reaching into a shallow, newly discovered lipophilic pocket lined by Val282, Val45, and Leu68. The binding mode of several of these ligands in the active site of TGT was established by crystal structure analyses (Figs. 4 and 6). A dramatic S effect was observed, with the replacement of the S‐atom in the (phenylsulfanyl)methyl residue in position 8 of inhibitor 1c (Ki=100 nM) by the O‐atom (in 1h, Ki=5.6 μM) or CH2 (in 1i, Ki=3.6 μM), resulting in a massive loss of activity (Fig. 3). Crystal structure analysis showed that the lipophilic Me group points into a highly polar region of the active site encompassed by the side chains of Asp280 and Asp102 and collides directly (d(C⋅⋅⋅O)=3.1 Å) with one of the O‐atoms of the carboxylate of Asp102. Similarly, lipophilic linkers departing from position 8 and orienting residues in the shallow hydrophobic pocket presumably encounter analogous unfavorable contacts, accounting for the modest contribution to the binding free enthalpy upon introduction of these residues. These findings provide a valuable starting point for future structure‐based lead optimization cycles leading to TGT inhibitors with increased in vitro potency.
Four New Dibenzocyclooctene Lignans from Kadsura renchangiana
Authors: Chen Min , Liao Zhixin , Chen Daofeng
Published: June 2004

Four new dibenzocyclooctene‐type lignans, named renchangianins A–D (1–4), were isolated from the stems of Kadsura renchangiana. Their structures and configurations were elucidated by spectroscopic methods, including 2D‐NMR techniques. Renchangianin D (4) possesses a spiro[dibenzocyclooctene‐6,2′‐oxirane] parent structure previously unknown in plants of the Schisandraceae family.
Studies on Direct Stereoselective Aldol Reactions in Aqueous Media
Authors: Wu Yin‐Su , Shao Wei‐Yan , Zheng Chuan‐Qi , Huang Zhong‐Li , Cai Jiwen , Deng Qin‐Ying
Published: June 2004

The direct aldol reaction of 4‐nitrobenzaldehyde catalyzed by NaHCO3, with three different ketones, Znproline, NaHCO3/Znproline, and L‐proline/Znproline in aqueous media, was studied to explore the selectivity of this environmentally benign type of reaction. Amazingly, NaHCO3 proper was found to be an efficient catalyst for the selective synthesis of β‐hydroxy ketones, showing good regio‐ and diastereoselectivity, with all reactions being completed within 9 h. Cyclopentanone and cyclohexanone were found to give rise to reversed diastereoisomer ratios, the syn and anti isomers being the major products, respectively – an unprecedented result. Also, the observed syn diastereoselectivity of aldol reactions catalyzed by L‐proline and Znproline is remarkable. The corresponding condensation products 7 and 8 were characterized by 1H‐NMR and single‐crystal X‐ray analyses. Finally, a chelate‐ vs. nonchelate‐type transition state is proposed to account for the differential diastereoselectivities.
Echinosporamicin, a New Antibiotic Produced by Micromonospora echinospora ssp. echinospora, LL‐P175
Authors: He Haiyin , Yang Hui Y. , Luckman Scott W. , Bernan Valerie S. , Tsai Gordon , Roll Deborah M. , Carter Guy T.
Published: June 2004

Echinosporamicin (1), a novel antibiotic containing an aromatic polycyclic system and a piperazinone moiety, was isolated from the fermentation broth of a new strain of Micromonospora echinospora subspecies echinospora, LL‐P175. The structure of this compound was determined by spectroscopic analysis by using variable‐temperature NMR techniques. Compound 1 exhibited potent activity against methicillin‐resistant Staphylococci and vancomycin‐resistant Enterococci strains. The methyl, ethyl, and benzyl esters showed improved antibacterial activity against Streptococci.
Derivatives from Isoselenocyanates: Synthesis of 2‐Phenyl‐6H‐[5,1,3]benzoselenadiazocine
Authors: Atanassov Plamen K. , Linden Anthony , Heimgartner Heinz
Published: June 2004

The reaction of N‐phenylbenzimidoyl isoselenocyanates 8 with primary and secondary amines in acetone at room temperature, followed by treatment with a base, led to 6H‐[5,1,3]benzoselenadiazocine derivatives of type 10 (Scheme 3). An analogous cyclization was observed when 8a and 8b were reacted with the Na salt of diethyl malonate in EtOH at room temperature, which yielded the eight‐membered selenaheterocycles 11 (Scheme 5). The molecular structures of some of the products, as well as that of a sulfur analogue, have been established by X‐ray crystallography (Figs. 1–4). The isoselenocyanates 8 have been prepared from N‐(2‐methylphenyl)benzamides 5 in a three‐step procedure via the corresponding imidoyl chlorides 6, side‐chain chlorination to give 7, and treatment with KSeCN (Scheme 2).
Enantioselective Preparation of β2‐Amino Acids with Aspartate, Glutamate, Asparagine, and Glutamine Side Chains
Authors: Lelais Gérald , Campo Marino A. , Kopp Sascha , Seebach Dieter
Published: June 2004

(S)‐β2‐Homoamino acids with the side chains of Asp, Glu, Asn, and Gln have been prepared and suitably protected (N‐Fmoc, CO2tBu, CONHTrt) for solid‐phase peptide syntheses. The key steps of the syntheses are: N‐acylation of 5,5‐diphenyl‐4‐isopropyl‐1,3‐oxazolidin‐2‐one (DIOZ) with succinic and glutaric anhydrides (Scheme 2), alkylation of the corresponding Li‐enolates with benzyl iodoacetate and Curtius degradation (Scheme 4), and removal of the chiral auxiliary (Scheme 5). In addition, numerous functional‐group manipulations (CO2H⇌CO2tBu, CO2Bn⇌CO2H, CbzNH→FmocNH, CO2H→CO2NH2→CONHTrt; Schemes 2, 4, 5, and 6) were necessary, in order to arrive at the four target structures. The configurational assignments were confirmed by X‐ray crystal‐structure determinations (Scheme 2 and Fig. 3). The enantiomeric purities of a β2hAsn and of a β2hGln derivative were determined by HPLC on a Chiralcel column to be 99.7 : 0.3 and >99 : 1, respectively (Fig. 4). Notably, it took up to twelve steps to prepare a suitably protected trifunctional product with a single stereogenic center (overall yield of 10% from DIOZ and succinic anhydride)!
Azo‐Coupling Reactions Used in Analytical Chemistry: The Role of Reactants, Intermediates, and Aqueous Medium
Authors: Pankratov Alexei N.
Published: June 2004

A quantum‐chemical study of the analytically important azo‐coupling reactions of naphthalen‐1‐amine (1) with naphthalene‐1‐diazonium (2) and 4‐sulphobenzenediazonium (8) cations has been carried out. The reactions have been found to be frontier‐controlled, and their regioselectivity is unequivocally determined by the thermodynamics of the intermediate σ‐complexes, as well as by the aqueous medium. The latter defines high positional selectivity, providing the decision between two possible reaction routes predicted on the basis of quantum‐chemical computations for separate molecular systems. As a result, azo coupling occurs at the 4‐ rather than at the 2‐position of 1. Furthermore, the aqueous medium makes the selection of analytical forms – protonated azo‐coupling products with a quinonehydrazone‐type structure.
Cyclic mechanical strain alters tissue‐factor activity in rat osteosarcoma cells cultured on a titanium substrate
Authors: Bledsoe J. Gary , Slack Steven M. , Turitto Vincent T.
Published: June 2004

Tissue factor (TF), a transmembrane glycoprotein, plays a role in the initiation of blood coagulation at sites of vascular injury. Activated products of coagulation may then enhance inflammatory responses. The present investigation assesses the ability of rat osteosarcoma (UMR‐106) cells cultured on titanium alloy (Ti6Al4V) to express differential surface TF activity in response to cyclic mechanical strain. Strains ranged from −2000 μ‐strain to +2000 μ‐strain, and durations from 5, 10, and 20 min per day over 5 days to 24 h continuous stimulation. ROS cells exhibited significant TF activity as demonstrated by the conversion of Factor X to Factor Xa. Strains of +2000 μ‐strain with 5–20‐min duration exhibited decreased TF activity with duration from 1.4E‐04 nM/cell to 8.7E‐05 nM/cell. Additionally, ROS cells stimulated with calcium ionophore (A23187) exhibited at least twice the activity of nonstimulated cells. Strains of +1340 μ‐strain with 5–20‐min duration exhibited an increasing trend with 4.15E‐05 nM/cell to 7.38E‐05 nM/cell. Strain direction had no significant effect on TF activity. Thus, both mechanical and chemical stimuli induce differential expression of TF activity by ROS cells cultured on Ti6Al4V, a phenomenon that may potentiate or regulate the inflammatory responses associated with the implantation of orthopedic biomaterials. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 70A: 490–496, 2004
Comparative biology of the ubiquitous Na+/H+ exchanger, NHE1: Lessons from erythrocytes
Authors: Pedersen Stine Falsig , Cala Peter Michael
Published: June 2004

By virtue of their electroneutral exchange of intracellular H+ for extracellular Na+, the Na+/H+ exchangers (NHE1‐NHE8) play a pivotal role in many physiological processes. This review focuses on the ubiquitous plasma membrane isoform, NHE1. Particular attention is given to the roles and regulation of NHE1 in erythrocytes, in their own right and as model systems, but pertinent findings from non‐erythroid cells are also discussed. NHE1 plays a key role in the regulation of cell volume and pH, and consequently in the control of such diverse processes as blood O2/CO2 transport, and cell proliferation, motility, and survival. Disturbances in NHE1 function are involved in important pathological states such as hypoxic cell damage and cancer development. NHE1 has a predicted topology of 12 transmembrane domains, and a hydrophilic C‐terminus thought to be the major site for NHE1 regulation. NHE1 is highly conserved throughout the vertebrate phylum, particularly in the transmembrane region and the proximal part of the C‐terminus. In non‐erythroid, and probably also in erythroid cells, this part of the hydrophilic C‐terminus interacts with multiple binding partners important for NHE1 function. Erythrocyte NHE1s from mammalian, amphibian, and teleost species are activated by cell shrinkage, decreased pHi, inhibition of Ser/Thr protein phosphatases, and activation of Ser/Thr protein kinases, i.e., many of the stimuli activating NHE1 in non‐erythroid cells. In erythrocytes of many lower vertebrates, NHE1 is activated during hypoxia and is an important modulator of hemoglobin oxygen affinity. Sensitivity of NHE1 to oxygenation status has recently been described also in non‐erythroid mammalian cells. J. Exp. Zool. 301A:569–578, 2004. © 2004 Wiley‐Liss, Inc.
Simultaneous production of triploid and haploid eggs by triploid Squalius alburnoides (Teleostei: Cyprinidae)
Authors: Alves M. Judite , Gromicho Marta , Collares‐Pereira M. João , Crespo‐López Elena , Coelho M. Manuela
Published: June 2004

The hybrid minnow Squalius alburnoides comprises diploid and polyploid forms with altered modes of reproduction. In the present paper, we report a cross where a triploid female generated both large, triploid and small, haploid eggs simultaneously, which were fertilized with S. pyrenaicus sperm. Although the large eggs were rarer (15%), they originated offspring with higher survivorship, so that tetraploids were dominant among the surviving siblings. The cross yielded apparently all female progeny. Inheritance patterns were inferred using four microsatellite markers and NORs (Nucleolus Organizer Regions) phenotypes, and suggested that haploid eggs were probably produced by an atypical hybridogenesis, in which the elimination of the unmatched genome permitted random segregation and recombination between the homospecific genomes, while the triploid eggs were clonal. The present results suggest that the occurrence of triploid unreduced eggs may be a new route for the natural tetraploidization in the complex. J. Exp. Zool. 301A:552–558, 2004. © 2004 Wiley‐Liss, Inc.
Oviductal sperm storage in the ground skink Scincella laterale holbrook (Reptilia: Scincidae)
Authors: Sever David M. , Hopkins William A.
Published: June 2004

The reproductive tracts of female ground skinks, Scincella laterale, collected at various times throughout their reproductive cycle were examined by light and transmission electron microscopy. Examination of the tracts revealed that sperm are retained in the posterior vagina after mating but prior to the ovulation of oocytes. The sperm are not sequestered in specialized glands but occur in scattered clusters in the lumen or among the deep, narrow rugae. The simple columnar lining of the vagina consists mostly of ciliated cells interspersed with occasional secretory cells. After ovulation, as indicated by the presence of eggs in the uterus, sperm are not found in the vagina. No sperm or sperm storage tubules occur in the infundibulum, the characteristic location for sperm storage in scleroglossid squamates that have been studied. Our results are a further indication that too few species have been examined to construct a rigorous phylogenetic hypothesis about the occurrence of sperm storage tubules in lizards. J. Exp. Zool. 301A:599–611, 2004. © 2004 Wiley‐Liss, Inc.
Protein location and elemental composition of urine spheres in different avian species
Authors: Casotti Giovanni , Braun Eldon J.
Published: June 2004

We examined the internal morphology, location of protein, and identity and location of elements, in avian urate‐containing spheres in 9 species of birds. The urine spheres were collected from voided samples. The spheres ranged in size from 0.5–5.0 µm, except in the domestic fowl, where they ranged up to 10 µm in diameter. The internal morphology of the spheres was examined using freeze‐fracture microscopy. Protein location within the spheres was identified using fluorescein isothiocyanate (FITC). The urine spheres were analyzed for content and internal location of elements using Energy Dispersal System Analysis (EDS). Internally, the spheres consisted of a central nidus surrounded by 3–4 concentric narrow rings of protein. Elements found within the spheres included nitrogen, potassium, calcium, sodium, phosphorus, chloride and sulfur; however, only nitrogen, potassium and chloride were common in the spheres of all species. Nitrogen comprised the majority of the elemental content of the spheres (77–90%) followed by potassium (8–45%), with all other ions present in trace amounts. Unlike protein, the location of elements was random within the spheres. Protein and urate are both negatively charged and known to associate to form the spheres and as potassium is the only cation common to all spheres, it too may play a role in their formation. J. Exp. Zool. 301A:579–587, 2004. © 2004 Wiley‐Liss, Inc.
Advances in membrane receptor screening and analysis
Authors: Cooper Matthew A.
Published: June 2004

During the last decade there has been significant progress in the development of analytical techniques for the screening of ligand binding to membranes and membrane receptors. This review focuses on developments using label‐free assays that facilitate ligand–membrane–receptor screening without the need for chemical‐, biological‐ or radiological‐labelled reagents. These assays include acoustic, optical surface plasmon resonance biosensing, sedimentation (analytical ultracentrifugation), chromatographic assays, isothermal titration calorimetry and differential scanning calorimetry. The merits and applications of cell‐based screening systems and of different model membrane systems, including planar supported lipid layers, bead‐supported membranes and lipid micro‐arrays, are discussed. Recent advances involving more established techniques including intrinsic fluorescence, FRET spectroscopy, scintillation proximity assays and automated patch clamping are presented along with applications to peripheral membrane proteins, ion channels and G protein‐coupled receptors. Novel high‐throughput assays for determination of drug‐ and protein‐partitioning in membranes are also highlighted. To aid the experimenter, a brief synopsis of the techniques commonly employed to purify and reconstitute membranes and membrane receptors is included. Copyright © 2004 John Wiley & Sons, Ltd
De novo adipose formation in a vascularized engineered construct
Authors: Walton Robert L. , Beahm Elisabeth K. , Wu Liza
Published: June 2004

While the field of tissue engineering is a burgeoning one, progress with fat engineering has lagged, due in large part to problems associated with nurturing and sustaining this unique tissue in vivo. In a pilot study using an experimental rat model, we induced liponeogenesis with a combination of Matrigel and basic fibroblast growth factor in an fibrovascular scaffold, isolating the construct to a pedicled blood supply (the superficial inferior epigastric vessels) via a silicone housing, creating an engineered three‐dimensional adipose tissue construct. Adipose tissue and vascular ingrowth were assessed histologically and followed by serial study at 4‐week intervals for 16 weeks. We demonstrated persistence of shaped adipose tissue constructs over time, and postulate that incorporating a vascular supply may enhance the durability of experimentally induced fat constructs and potentially provide a means for microsurgical transfer of the construct. © 2004 Wiley‐Liss, Inc.
Identification and analysis of stage‐specific expression of lysosome‐associated protein transmembrane 4α gene during development of preimplantation rabbit nuclear transfer embryo
Authors: Yu Weidong , He Xin , Liu Guisheng , Chen Qingxuan
Published: June 2004

The stage‐specific expression of Lysosome‐associated protein transmembrane 4α (LAPTM4α) in preimplantation rabbit nuclear transfer (NT) embryo was identified with the DDRT‐PCR and reverse Northern Blot. The full length (1,364 bp) cDNA of LAPTM4α was screened out from cDNA library constructed with rabbit ovary and in situ hybridization (ISH) was used to trace the distribution of the LAPTM4α mRNA in intra‐ovary, especially the follicle which proved that the LAPTM4α gene expression is involved in the follicles development, maturation, ovulation, luteinization, and preimplantation development in the rabbit (Oryctolagus cuniculus domestica). To our knowledge, this is the first characterization of LAPTM4α gene expression and mRNA distribution in the rabbit ovary and first evidence for this gene involving in follicle development and rabbit preimplantation development. Mol. Reprod. Dev. 68: 415–421, 2004. © 2004 Wiley‐Liss, Inc.
Carbohydrates and glycoproteins involved in bovine fertilization in vitro
Authors: Tanghe S. , Van Soom Ann , Duchateau L. , Nauwynck H. , de Kruif A.
Published: June 2004

In the present study, efforts were made towards identifying carbohydrates and glycoproteins involved in bovine in vitro fertilization (IVF). In vitro matured cumulus–oocyte complexes (COCs) were inseminated in the presence of a variety of carbohydrates and glycoproteins to determine which glycoconjugates act as competitive inhibitors of oocyte penetration. Among the carbohydrates and glycoproteins tested, D‐mannose, fucoidan, dextran sulfate, and fibronectin were the most potent inhibitors of oocyte penetration (90% or more inhibition), while L‐fucose and vitronectin inhibited the penetration rate to a lesser extent (around 50% inhibition). Other carbohydrates caused less than 40% inhibition (i.e., D‐galactose, N‐acetyl‐D‐galactosamine, D‐fucose, and sialic acid) or were not effective as inhibitors of oocyte penetration (i.e., mannan, N‐acetyl‐D‐glucosamine, dextran, and heparan sulfate). Heparin was the only carbohydrate that significantly increased the penetration rate. To exclude a possible toxic effect on spermatozoa, sperm motility was evaluated over time by means of computer‐assisted sperm analysis in the presence of carbohydrates and/or glycoproteins that inhibited the penetration rate with 40% or more. L‐fucose, dextran sulfate, and vitronectin did not significantly influence total and progressive sperm motility, whereas D‐mannose, fucoidan, and fibronectin caused a significant, but slight reduction in both motility parameters. These results are indicative for the involvement of D‐mannose, L‐fucose, fucoidan, dextran sulfate, fibronectin, and vitronectin in bovine IVF. Mol. Reprod. Dev. 68: 492–499, 2004. © 2004 Wiley‐Liss, Inc.
Relationship between the morphological changes of somatic compartment and the kinetics of nuclear and cytoplasmic maturation of oocytes during in vitro maturation of porcine follicular oocytes
Authors: Somfai Tamás , Kikuchi Kazuhiro , Onishi Akira , Iwamoto Masaki , Fuchimoto Dai‐ichiro , Papp Ágnes Bali , Sato Eimei , Nagai Takashi
Published: June 2004

Based on the morphology and expansion of the cumulus cells, several different classes of porcine cumulus‐oocyte complexes (COCs) can be distinguished, during their maturation in vitro. The goal of the present study was to find out the rate of each morphologic category in case of COCs and granulosa‐cumulus‐oocyte complexes (GCOCs), the characteristics of their nuclear progression, cytoplasmic maturation, and the frequency of monospermy after IVF. It was found that the frequency of cumulus expansion is higher in case of GCOCs than that of COCs. Nuclear progression of COCs was more accelerated than that of GCOCs. Oocytes attached to the bottom of culture dish with dark, compact cumulus underwent nuclear and acquired their ability to be activated earlier than that of oocytes showing normal cumulus expansion. The rate of monospermic fertilization after IVF of normal COCs showing normal cumulus expansion was higher than that of COCs attached to the dish. These results suggest that diverse behavior of cumulus cells during in vitro culture affects nuclear and cytoplasmic maturation of porcine oocytes, which also affects IVF results. It can be concluded that granulosa cells promote normal cumulus expansion thus decrease heterogeneity in nuclear and cytoplasmic maturation amongst oocytes. Mol. Reprod. Dev. 68: 484–491, 2004. © 2004 Wiley‐Liss, Inc.
Germ cells enter meiosis in a rostro‐caudal wave during development of the mouse ovary
Authors: Bullejos Monica , Koopman Peter
Published: June 2004

Germ cells in the mouse embryo remain undifferentiated until about 13.5 days post‐coitum (dpc), when male germ cells enter mitotic arrest and female germ cells enter meiosis. The molecular signals and transcriptional control mechanisms governing the differential fate of germ cells in males and females remain largely unknown. In order to gain insights into the behavior of germ cells around this period and into likely mechanisms controlling entry into meiosis, we have studied by wholemount in situ hybridization the expression pattern of two germ cell‐specific markers, Oct4 and Sycp3, during mouse fetal gonad development. We observed a dynamic wave of expression of both genes in developing ovaries, with Oct4 expression being extinguished in a rostro‐caudal wave and Sycp3 being upregulated in a corresponding wave, during the period 13.5–15.5 dpc. These results indicate that entry into meiosis proceeds in a rostro‐caudal progression, in turn suggesting that somatically derived signals may contribute to the control of germ cell entry into meiosis in developing ovaries. Mol. Reprod. Dev. 68: 422–428, 2004. © 2004 Wiley‐Liss, Inc.
Investigation of estrogen receptor α and β mRNA expression in the pregnant rat uterus
Authors: Minorics Renáta , Ducza Eszter , Márki Árpád , PÁldy Eszter , Falkay George
Published: June 2004

Although the expressions of the estrogen receptor (ER) subtypes have been demonstrated in a large number of estrogen target tissues, to date no evidence has been reported as to how the expressions of the alpha (α) and beta (β) ER subtype mRNA alter in the rat uterus during pregnancy. The aims of the present study were to obtain information concerning the changes in the ER and the progesterone receptor (PR) in early pregnancy and to determine the alterations in the ER subtype mRNA in the pregnant rat uterus. To demonstrate the ER and PR densities, radioligand saturation assay was used. The reverse‐transcription‐polymerase chain reaction (RT‐PCR) was applied to characterize the alterations in the ER subtype mRNA. ER expression was highest on day 5 of pregnancy (Bmax = 637.40 ± 76.10 fmol/mg). The PR expression did not change significantly until day 8, but the protein density was increased on day 8 of pregnancy. The ERα mRNA expression was active during pregnancy, maximum expression was attained on day 5; a gradual decrease was then observed until the second half of pregnancy when its expression continuously increased up to the day of labor (day 22). Since the attachment of the blastocyst, an event that is dependent on estradiol in the progesterone‐primed uterus of the rat, occurs on day 5 of pregnancy and the levels of the ER protein and the ERα mRNA on day 5 of pregnancy was the highest, it could be supposed that this subtype of ER might regulate implantation. The ERβ mRNA was detected only from day 7 to day 15, with a maximum level on day 8. The expression of this ER subtype might be related to the development of decidual tissue. Mol. Reprod. Dev. 68: 463–468, 2004. © 2004 Wiley‐Liss, Inc.
Evidence that P36, a human sperm acrosomal antigen involved in the fertilization process is triosephosphate isomerase
Authors: Auer Jana , Camoin Luc , Courtot Anne‐Marie , Hotellier Françoise , De Almeida Marta
Published: June 2004

P36 is one of the immunodominant sperm antigens identified by antibodies eluted from the spermatozoa of infertile men. In a previous study, we isolated and characterized this auto‐antigen as a glycoprotein with several isoforms. Specific rabbit antibodies were produced to investigate sperm topography and the role of P36 in the fertilization process and we showed that P36 is present on the equatorial segment of acrosome‐reacted spermatozoa and is involved in sperm‐binding and the penetration of zona‐free hamster oocytes. In the present study, we demonstrated, by means of immunofluorescence and electron microscopy, that P36 is present all over the acrosomal membranes of non‐reacted spermatozoa. We also investigated the role of P36 in the acrosome reaction and sperm binding to the zona pellucida (ZP). The exposure of capacitated spermatozoa to rabbit anti‐P36 antibodies had no effect on primary fixation to the ZP, but inhibited secondary binding to the ZP and the Ca2+ ionophore‐induced acrosome reaction. These results suggest that P36, an acrosomal antigen, is involved in several steps of the fertilization process. On two‐dimensional Western blots, human anti‐sperm antibodies (ASA) and rabbit anti‐P36 antibodies recognized five to six isoforms of P36, all 36/37 kDa in size, with a pI between 5.1 and 5.7. Two major spots were identified as human triosephosphate isomerase (TPI) by MALDI‐TOF mass spectrometry. Anti‐TPI antibodies were shown to react with the isoforms recognized by human and rabbit anti‐P36 antibodies. We also demonstrated the presence of TPI in human sperm heads. Further studies are underway to establish whether there is a sperm‐specific isoform of TPI and its role in sperm function. Mol. Reprod. Dev. 68: 515–523, 2004. © 2004 Wiley‐Liss, Inc.
Distribution of prepubertal and adult goat oocyte cortical granules during meiotic maturation and fertilisation: Ultrastructural and cytochemical study
Authors: Velilla E. , Izquierdo D. , Rodríguez‐González E. , López‐Béjar M. , Vidal F. , Paramio M.T.
Published: June 2004

The aim of this study was evaluate cortical granule (CG) distribution during in vitro maturation (IVM) and fertilisation of prepubertal goat oocytes compared to CG distribution of ovulated and in vitro fertilised oocytes from adult goats. Oocytes from prepubertal goats were recovered from a slaughterhouse and were matured in M199 with hormones and serum for 27 hr. Ovulated oocytes were collected from gonadotrophin treated Murciana goats. Frozen‐thawed spermatozoa were selected by centrifugation in percoll gradient and were capacitated in DMH with 20% steer serum for 1 hr. Ovulated and IVM‐oocytes were inseminated in DMH medium with steer serum and calcium lactate for 20 hr. Oocytes and presumptive zygotes were stained with FITC‐LCA (Lens culinaris agglutinin labelled with fluorescein isothiocyanate) and observed under a confocal laser scanning microscope. Ultrastructure morphology of oocytes and presumptive zygotes were analysed by transmission electron microscopy (TEM). Prepubertal goat oocytes at germinal vesicle stage show a homogeneous CG distribution in the cytoplasm. IVM‐oocytes at Metaphase II (MII) and ovulated oocytes presented CGs located in the cortex with the formation of a monolayer beneath to the plasma membrane. At 20 hr postinsemination (hpi), zygotes from IVM‐oocytes showed a complete CG exocytosis whereas zygotes from ovulated oocytes presented aggregates of CGs located at the cortical region. Images by TEM detected that CGs were more electrodense and compacts in oocytes from prepubertal than from adult goats. Mol. Reprod. Dev. 68: 507–514, 2004. © 2004 Wiley‐Liss, Inc.
Effects of desipramine and MK‐801 on components of muricidal behaviour in olfactory bulbectomized rats: An application of incisor‐cutting animal model
Authors: Ho Ying‐Jui , Hsuchou Hung , Chen Kuang‐Ho , Shui Hao‐Ai , Tai Mei‐Yun , Tsai Yuan‐Feen
Published: June 2004

Both desipramine and MK‐801 are reported to suppress the muricidal behaviour and more behavioural components of muricide can be measured for analyses in rats after incisor cutting (IC). In the present work, this IC model was used to assess the differential effects of desipramine and MK‐801 on muricidal performance in rats. After IC surgery the olfactory bulbectomized rats were divided into five groups that were then treated with saline (1 ml/kg, i.p.), desipramine (10 or 20 mg/kg, i.p.), or MK‐801 (0.10 or 0.15 mg/kg, i.p.). Following drug administration, muricidal behaviour was found to be unchanged in the low‐dose desipramine or MK‐801 groups compared with the saline controls. Treatment with 20 mg/kg of desipramine increased the attack latency, but reduced the total and mean attack duration as well as attack frequency, while treatment with 0.15 mg/kg of MK‐801 resulted in no significant change in the attack latency or total attack duration, but decreased the mean attack duration and increased the attack frequency. These results indicate that the higher dose of both drugs affected the components of the muricidal behaviour in different manners.
Resolution of the region of secondary somatosensory cortex that responds to stimulation of the horizontal semicircular canal in rats
Authors: Park Byung Rim , Soh Byung Soo , Kim Min Sun , Lee Moon Young , Kim Jae Hyo , Chun Sang Woo
Published: June 2004

To elucidate the region within the somatosensory cortex that receives inputs from the horizontal semicircular canal (HSC) in rats, we used a multichannel recording system to measure evoked potentials in the parietal cortex in response to electrical stimulation of the HSC nerve. The recordings suggested that the HSC nerves projected bilaterally into the somatosensory cortex, with a contralateral predominance. The territory within the somatosensory cortex that responded to the stimulation of the HSC nerve was as follows: mediolateral 6.0 mm and anteroposterior –1.3 ∼ –2.3 mm from the bregma, and depth 1.4 ∼ 1.6 mm from the cortex surface horizontally by stereotaxic atlas. The evoked potential in the parietal cortex that was induced by electrical stimulation was abolished after the administration of tetrodotoxin into the oval window of the vestibular system. These results suggest that the horizontal semicircular nerve projects bilaterally into the deep layers of the secondary somatosensory cortex.
Die swell ratio of polystyrene melt from an electro‐magnetized capillary die in an extrusion rheometer: effects of barrel diameter, shear rate and die temperature
Authors: Sombatsompop N. , Sergsiri S.
Published: June 2004

A constant shear‐rate extrusion rheometer with an electro‐magnetized capillary die was utilized to investigate die swell behavior and flow properties of a polystyrene melt as the application of an electro‐magnetic field to the capillary die was relatively novel in polymer processing. The test conditions such as magnetic flux density, barrel diameter, extrusion rate and die temperature were studied. The results suggest that the maximum swelling of the polystyrene melt with application of the electro‐magnetic field could be enhanced up to 2.6 times (260%) whereas that without the electro‐magnetic field was 1.9 times (190%). The barrel diameter of 30 mm was found to be a critical value in the case of the die swell ratio and flow properties of the polystyrene melt were significantly affected by the magnetic flux density. This involved the number and angle of magnetic flux lines around the barrel part. Under the electro‐magnetic field, there were two mechanical forces influencing the die swell ratio and the flow properties; magnetic torque and shearing force. The die swell at wall shear rates less than 11.2 sec−1 was caused by the magnetic torque, whereas at higher wall shear rates it was dependent on the shearing force. For a given magnetic flux density, the maximum increase in the die swell ratio as a result of the magnetic torque was calculated to be approximately 20%. Increasing the die temperature from 180 to 200°C reduced the overall die swell ratio and suppressed the effect of the magnetic flux density. Copyright © 2004 John Wiley & Sons, Ltd.
Mechanical properties and structural characteristics of PP/PP‐g‐SBR nanocomposites prepared by dynamical photografting
Authors: Wang Weizhi , Fu Mouzheng , Qu Baojun
Published: June 2004

Poly(propylene) (PP)/PP grafted styrene‐butadiene rubber (PP‐g‐SBR) nanocomposite was prepared by blending PP with PP‐g‐SBR using dynamical photografting. The crystal morphological structure, thermal behavior, and mechanical properties of PP/PP‐g‐SBR nanocomposites have been studied by photoacoustic Fourier transform infrared spectroscopy (PAS‐FT‐IR), wide‐angle X‐ray diffraction (WAXD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and mechanical measurements. The data obtained from the mechanical measurements show that the PP‐g‐SBR as a modifier can considerably improve the mechanical properties of PP/PP‐g‐SBR nanocomposites, especially for the notched Izod impact strength (NIIS). The NIIS of the nanocomposite containing 2 wt% PP‐g‐SBR measured at 20°C is about 2.6 times that of the control sample. The results obtained from PAS‐FTIR, WAXD, SEM, and DSC measurements revealed the enhanced mechanism of impact strength of PP/PP‐g‐SBR nanocomposites as follows: (i) the β‐type crystal of PP formed and its content increased with increasing the photografting degree of PP‐g‐SBR; (ii) the size of PP‐g‐SBR phase in the PP/PP‐g‐SBR nanocomposites obviously reduced and thus the corresponding number of PP‐g‐SBR phase increased with increasing the photografting degree of PP‐g‐SBR. All the earlier changes on the crystal morphological structures are favorable for increasing the compatibility and enhancing the toughness of PP at low temperature. Copyright © 2004 John Wiley & Sons, Ltd.
The study of the miscibility and morphology of poly(styrene‐co‐4‐vinylphenol)/poly(propylene carbonate) blends
Authors: Qiu Furong , Chen Shiming , Tan Li , Ping Zhenghua
Published: June 2004

Blends of poly(propylene carbonate) (PPC) with copolymer poly(styrene‐co‐4‐vinyl phenol) (STVPh) have been studied by electron spin resonance (ESR) spin probe method and Raman spectroscopy. The ESR results indicated that the nitroxide radical existed in a PPC‐rich and an STVPh‐rich micro domain in the blends, corresponding to the fast‐motion and slow‐motion component in the ESR spectra, respectively. And in the temperature dependence composite spectra, the fast‐motion fraction increased with increasing the hydroxyl group content in copolymer STVPh. Moreover, the ESR parameter T5mT, rotational correlation times (τc) and activation energies (Ea) showed similar dependence on the hydroxyl group content as the fast‐motion fraction. It resulted from the enhancement of the hydrogen‐bonding interaction between the hydroxyl groups in STVPh and the carboxyl groups and ether oxygen in PPC. However, the distinct band shift and intensity change among the Raman spectra of pure polymer components and those of the blends were observed. In the carboxyl‐stretching region, the band shifted to lower frequency with increasing the hydroxyl groups. Furthermore, the phase morphologies of the blends were obtained by optical microscopy. All could be concluded that the hydrogen‐bonding interaction between the two components was progressively favorable to the mixing process and was the driving force for the miscibility enhancement in the blends. Copyright © 2004 John Wiley & Sons, Ltd.
Congenital diaphragmatic hernia: prenatal diagnosis permits immediate intensive care with high survival rate in isolated cases. A population‐based study
Authors: Bétrémieux Pierre , Gaillot Théophile , de la Pintière Armelle , Beuchée Alain , Pasquier Laurent , Habonimana Edouard , Le Bouar Gwénaelle , Branger Bernard , Milon Joëlle , Frémond Benjamin , Wodey Eric , Odent Sylvie , Poulain Patrice , Pladys Patrick
Published: June 2004

Objectives

To estimate the prognosis of prenatally diagnosed isolated congenital diaphragmatic hernia (PDICDH) treated with ‘immediate planned care’ (IPC) between 1999 and 2003 in Eastern Brittany.

Methods

The prognosis of PDICDH was compared with the prognosis of the other live‐born CDH, either prenatally undiagnosed or not having had IPC. IPC consisted in prenatal lung maturation with corticosteroids, elective caesarean section at 37 weeks, immediate intubation, surfactant, high‐ frequency ventilation or oscillation, nitric oxide, intravenous prostacyclin, anaesthesia and haemodynamic support. Surgical repair was performed in the NICU 34 h after birth.

Results

The incidence of CDH was 0.8‰ with a prenatal diagnosis rate of 27/30 (90%), leading to a termination of pregnancy in nine cases. Ten CDH were associated with other malformations. IPC in PDICDH was performed in 12 cases. The survival rate of PDICDH with IPC was 11/12 versus 1/9 in CDH with no IPC or no prenatal diagnosis (p < 0.01). Logistic regression analysis showed that IPC was determinant for survival (p < 0.01).

Conclusion

Prenatal diagnosis of isolated CDH treated with immediate planned care is associated with a high survival rate. This suggests that prenatal diagnosis associated with specifically adapted postnatal procedure may improve the prognosis of isolated CDH. Copyright © 2004 John Wiley & Sons, Ltd.
Ethnicity and prevalence of diabetic complications in elderly patients
Authors: Hewitt J , Gallen I
Published: June 2004

The objective of this study was to assess whether ethnicity plays a role in the prevalence of diabetic complications in elderly patients.

Data were collected by prospective computerised audit on 834 diabetic patients in a district general hospital in South Buckinghamshire, UK. The patients were aged over 60 and of different ethnic backgrounds: 692 Caucasians (C), 60 Afro‐Caribbeans/Africans (A) and 82 South Asians (SA). Mean HbA1c, microalbuminuria, retinopathy and treated hypertension were analysed and compared.

The results showed that mean (SD) HbA1c was 8.8% (1.9%) for the C group and 8.6% (2.1%) for the SA group, but was higher in the A group (9.3% [2.1%]) (p=0.034 vs C; p=0.044 vs SA). Microalbuminuria (>15mg albumin/12 hours) was not statistically different in the C and A groups (102 [14.7%] vs 11 [18.3%]), but was higher in the SA group (19 [23.2%]) (p=0.050 vs C). Retinopathy (identified by an ophthalmologist at the retinal screening clinic) was found in 254 (36.7%) of the C group, in 24 (40.0%) of the A group and less frequently in the SA group (21 [25.6%], p=0.063 vs A; p=0.054 vs C). Hypertension (patients currently taking antihypertensive medication) was found in 282 (40.8%) of the C group, more frequently in the A group (34 [56.7%], p=0.022) and less frequently in the SA group (24 [29.3%], p<0.001 vs A; p=0.049 vs C).

In conclusion, glycaemic control was worst in the A group. Retinopathy and hypertension were most frequent in the A group. The SA group had a lower prevalence of retinopathy and treated hypertension; however, they had a higher prevalence of microalbuminuria. The frequency of diabetic complications was different between ethnic groups, particularly group A. These differences may be the result of antecedent glycaemic control, hypertension or ethnicity. Copyright © 2004 John Wiley & Sons, Ltd.
Cultural barriers to diabetes care in South Asians: arranged marriage – arranged complications?
Authors: Goenka N , Dobson L , Patel V , O'Hare P
Published: June 2004

Social and cultural differences that are present in South Asian diabetic patients may affect their diabetes care. We present a case concerning a young South Asian girl with type 2 diabetes mellitus who, despite persistent attempts at education and encouragement by health care professionals, was unwilling to accept treatment of her diabetes. It was felt by both herself and her family that acceptance of the diagnosis of diabetes would adversely affect her marriage prospects. As a result she developed severe microvascular complications before she finally agreed to treatment. Understanding potential cultural barriers to diabetes care may be vital in managing South Asian diabetic patients and it is important to establish education programmes specifically aimed at removing the perceived stigma of diabetes in this population. Copyright © 2004 John Wiley & Sons, Ltd.
Understanding painful symptomatic diabetic neuropathy
Authors: Boulton AJM
Published: June 2004

Neuropathic pain is a common and disabling condition affecting a significant number of diabetic patients with distal polyneuropathy. Fluctuations in blood glucose levels have been shown to exacerbate neuropathic pain and initial treatment should therefore focus on achieving tight glycaemic control. The role of patient education is achieving greater importance and a patient's understanding of diabetic complications and their causes can significantly improve outcomes. Nevertheless, the majority of patients require some form of treatment in order to effectively manage their pain. There are a number of therapeutic agents available, such as the tricyclic drugs which have been used with good effect for years, but also more recent additions, such as gabapentin, which is now licensed for the treatment of neuropathic pain. Copyright © 2004 John Wiley & Sons, Ltd.
Modification of bismaleimide resin by soluble poly(ester imide) containing trimellitimide moieties
Authors: Iijima Takao , Hayashi Nobuaki , Oyama Toshiyuki , Tomoi Masao
Published: June 2004

Poly(ester imide)s containing trimellitimide moieties have been used to reduce the brittleness of the bismaleimide resin composed of 4,4′‐bismaleimidediphenyl methane and o,o′‐diallyl bisphenol A. The poly(ester imide)s include poly[ethylene phthalate‐co‐ethylene N‐(1,4‐phenylene)trimellitimide dicarboxylate]s containing 20–40 mol% trimellitimide (TI) unit, and poly[trimethylene phthalate‐co‐trimethylene N‐(1,4‐phenylene)trimellitimide dicarboxylate]s (PESIP) containing 20 mol% TI unit. The poly(ester imide)s are effective modifiers for reducing the brittleness of the bismaleimide resin. For example, when using 30 wt% of PESIP (20 mol% TI unit, Mw 13 500 g mol−1), the fracture toughness (KIC) for the modified resin is increased by 80% with retention in flexural properties and a slight loss of the glass transition temperature, compared with the values of the unmodified cured bismaleimide resin. Microstructures of the modified resins have been examined by scanning electron microscopy and dynamic viscoelastic analysis. The toughening mechanism is discussed in terms of the morphological and dynamic viscoelastic behaviour of the modified bismaleimide resin system.

© 2004 Society of Chemical Industry
Blue‐shifted dihydrogen bonds
Authors: Feng Yong , Zhao Su‐Wen , Liu Lei , Wang Jin‐Ti , Li Xiao‐Song , Guo Qing‐Xiang
Published: June 2004

Blue‐shifted dihydrogen bonds were predicted to be present in a number of non‐covalent complexes including F3C—H…H—Be—X, F3C—H…H—Mg—X, F3C—H…H4Si, F3Si—H…H—Li, F3Si—H…H—Be—X, F3Si—H…H—Mg—X, and F3Si—H…H4Si (X = H, F, Cl and CH3). Pauli and nuclei–nuclei repulsions between the protonic hydrogen and hydridic hydrogen are proposed as the cause of the blue shift. Copyright © 2004 John Wiley & Sons, Ltd.
Intriguing double‐inversion stereochemistry in the denitrogenation of 2,3‐diazabicyclo[2.2.1]heptene‐type azoalkanes: a model mechanistic study in physical organic chemistry
Authors: Adam Waldemar , Diedering Manfred , Trofimov Alexey (Alexei) V.
Published: June 2004

In this review is given a detailed account of the mechanistic elucidation of the unique stereochemical double inversion observed in the nitrogen extrusion of bicyclic azoalkanes. It is shown that the judicious choice of experimental tools and theoretical approaches provides insight into and understanding of this perplexing stereoselectivity. This long‐standing mechanistic query serves as an example par excellence of harnessing the structural variation of the DBH‐type substrate (internal effects) and the change of medium properties (external effects) to diagnose a complex reaction mechanism. The particular case reviewed here is specific, but the focus in resolving its mechanistic complexities is general and, thus, may be applied to the elucidation of other intricate reaction mechanisms, primarily stereoselective and product‐selective organic transformations. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis and phase behavior of side‐chain liquid‐crystalline polymers containing malachite green lactone groups
Authors: Hu Jian‐She , Zhang Bao‐Yan , Wang Ying , Meng Fan‐Bao
Published: June 2004

New side‐chain liquid‐crystalline polymers containing both cholesteric and thermochromic side groups were synthesized. Their chemical structures were confirmed with elemental analyses and Fourier transform infrared, proton nuclear magnetic resonance, and carbon‐13 nuclear magnetic resonance spectra. The mesogenic properties and phase behavior were investigated with differential scanning calorimetry, thermogravimetric analysis, polarizing optical microscopy, and X‐ray diffraction measurements. The effect of the concentration of dye side groups on the phase behavior of the polymers was examined. The polymers showed smectic or cholesteric phases. Those polymers containing less than 20 mol % dye groups had good solubility, reversible phase transitions, wider mesophase temperature ranges, and higher thermal stability. The experimental results demonstrated that the isotropization temperature and mesophase temperature ranges decreased with an increasing concentration of dye groups. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3870–3878, 2004