bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diastereoreactivity of a Chiral Oxathiane Derived from 5‐Hydroxy‐1‐tetralone
Authors: Solladié‐Cavallo Arlette , Balaz Milan , Salisova Marta 
Published: December 2002

AbstractThe diastereoreactivity at the CH2 bridge of a cis‐oxathiane derived from 5‐hydroxy‐1‐tetralone (unprotected and protected at the OH) was studied, and it appeared that all reactions at C‐2 provided equatorial substitution. It was also found that: i) reductions of the equatorial benzoyl derivative with selectrides provided high diastereoselectivities at C‐2′ while LAH did not. Methyl Grignard addition was less selective and the selectivity of the propanoyl analogue was smaller; ii) condensation of aldehydes and/or ketones with the lithio derivative provided high equatorial diastereoselectivities at C‐2 but low or nil diastereoselectivities at C‐2′; iii) lithiation at C‐2 was possible only with the oxathiane unsubstituted at C‐2 (CH2) and not possible with derivatives substituted at C‐2 (CHR), perhaps due to the conformational rigidity of this oxathiane in the lithiation transition state and to the equatorial demand of all substituents at C‐2, including lithium. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Asymmetric Synthesis of 1,3‐Dithiolane Nucleoside Analogues
Authors: Caputo Romualdo , Guaragna Annalisa , Palumbo Giovanni , Pedatella Silvana 
Published: December 2002

AbstractWe report the ready asymmetric synthesis of nucleoside analogues containing a 1,3‐dithiolane ring that mimics the sugar moiety of natural nucleosides. The synthesis is accomplished in three main steps from benzoyloxyethanal 1,3‐dithiolane, the key step being its conversion into a chiral monosulfoxide by a modified Sharpless sulfo‐oxygenation reaction. The nucleoside analogues were obtained in good overall yields and with excellent enantiomeric excesses. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
TEMPO‐Mediated Anodic Oxidation of Methyl Glycosides and 1‐Methyl and 1‐Azido Disaccharides
Authors: Schämann Matthias , Schäfer Hans J. 
Published: December 2002

AbstractMethyl glycosides of L‐sorbopyranoside, D‐fructopyranoside, D‐glucosaminopyranoside, 2,3‐dehydro‐2,3‐dideoxyglucopyranoside, cellobiose, lactose, and maltose and the 1‐azido derivatives of glucose, cellobiose, lactose, and maltose have been converted into the corresponding uronic acids in moderate to excellent yields by TEMPO‐mediated anodic oxidation. The anode proves to be an advantageous alternative to other cooxidants in TEMPO+ oxidations of carbohydrates and is compatible with N‐acylamino and azido groups and with double bonds. The electrolyte, a carbonate buffer, can easily be removed with a cation‐exchange resin, a facile scale‐up by increasing the electrode area is possible. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Functionalization of 9‐(Dicyanomethylene)fluorene Derivatives with Substituted Acetylenes
Authors: Wong Wai‐Yeung , Lu Guo‐Liang , Choi Ka‐Ho , Lin Zhenyang 
Published: December 2002

AbstractTreatment of (2,7‐dibromo‐9H‐fluoren‐9‐ylidene)malononitrile (1) with excesses of substituted acetylenes RC≡CH [R = Ph, MeC6H4, (η5‐C5H5)Fe(η5‐C5H4)] under Sonogashira coupling catalytic conditions afforded novel 9‐[cyano(ethynyl)methylene]fluorene derivatives 2−4, respectively, in moderate yields. In these reactions, facile functionalization occurs at the 9‐methylene position in the fluorene, one of the cyano groups being substituted by an acetylide moiety. In order to prepare the 2,7‐diethynyl‐substituted 9‐(dicyanomethylene)fluorene compounds 8−10, palladium‐catalyzed coupling reactions between 2,7‐dibromofluoren‐9‐one and RC≡CH in a 1:2 molar ratio first have to be carried out, initially resulting in the formation of compounds 5−7 in good yields. Upon subsequent thermal treatment of 5−7 with malononitrile in DMSO, compounds 8−10 can be isolated in high purity. All attempts to obtain 8−10 from direct coupling of 1 and RC≡CH failed. Single‐crystal X‐ray structural analyses and density functional calculations have been performed on 3, 4, 7, and 8. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Synthesis of “V‐Shaped” syn‐Bidentate Ligands Based on Mesitylene‐Derived [1.1.1.1]Metacyclophane Blocked in a 1,3‐Alternate Conformation
Authors: Klein Cédric , Graf Ernest , Hosseini Mir W. , De Cian André , Kyritsakas‐Gruber Nathalie 
Published: December 2002

AbstractA series of five new syn‐bidentate ligands 14−18 based on the [1.1.1.1]metacyclophane backbone blocked in a 1,3‐alternate conformation was achieved. The common building block for the preparation of ligands bearing two interaction sites located in a syn fashion (CN, SMe, p‐pyridyl, p‐methoxyphenyl and p‐methylthiophenyl) is the dibromo derivative 12. All reported ligands were fully characterised by classical analytical methods and their 1,3‐alternate conformation demonstrated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Oviductal sperm storage structure and their changes during the seasonal (dissociated) reproductive cycle in the soft‐shelled turtle Lissemys punctata punctata
Authors: Sarkar Supriti , Sarkar N.K. , Maiti B.R. 
Published: December 2002

AbstractThe oviduct of the Indian fresh water soft‐shelled turtle Lissemys punctata punctata was examined throughout the year under light and scanning electron microscopes to determine the location, histomorphological characteristics, and function of sperm storage structure, as well as their changes at different phases of the seasonal reproductive cycle. Sperm storage structures in the form of tubules were observed in the wall of isthmus throughout the year. These tubules developed either by folding or fusion of the oviductal mucosal folds and were lined by both ciliated and nonciliated epithelial cells. The height and secretory activities of the epithelia were markedly high during the breeding phase (August to September) but low in the nonbreeding phase (October to June). A few short tubules lined by cuboidal epithelium appear in the wall of infundibulum only during the breeding phase. Following mating (May), inseminated sperm were stored within the tubules of isthmus up to the pre‐ovulatory stage (August). Thereafter, sperm associated with PAS‐positive materials secreted from the epithelium (referred to as a carrier matrix) moved forward to the infundibulum and were stored within the storage tubules of the infundibulum for a short time. Subsequently, sperm evacuated the storage tubules and entered the oviductal lumen to fertilize the subsequently ovulated eggs during or prior to ovulation. The isthmus‐tubules become shorter and narrower in the regressive phase (October to November) and remained so until the early preparatory phase (April). Sperm release might have been stimulated by estrogen secreted from the ovarian follicles of pre‐ovulatory turtles. Stored sperm not utilized for fertilization remained viable not less than six months in the present turtle species. J. Exp. Zool. 295A:83–91, 2003. © 2003 Wiley‐Liss, Inc.
Balancing tissue perfusion demands: cardiovascular dynamics of cancer magister during exposure to low salinity and hypoxia
Authors: McGaw Iain J. , McMahon Brian R. 
Published: December 2002

AbstractDecapod crustaceans inhabit aquatic environments that are frequently subjected to changes in salinity and oxygen content. The physiological responses of decapod crustaceans to either salinity or hypoxia are well documented; however, there are many fewer reports on the physiological responses during exposure to these parameters in combination. We investigated the effects of simultaneous and sequential combinations of low salinity and hypoxia on the cardiovascular physiology of the Dungeness crab, Cancer magister. Heart rate, as well as haemolymph flow rates through the anterolateral, hepatic, sternal and posterior arteries were measured using a pulsed‐Doppler flowmeter. Summation of flows allowed calculation of cardiac output and division of this by heart rate yielded stroke volume. When hypoxia and low salinity were encountered simultaneously, the observed changes in cardiac properties tended to be a mix of both factors. Hypoxia caused a bradycardia, whereas exposure to low salinity was associated with a tachycardia. However, the hypoxic conditions had the dominant effect on heart rate. Although hypoxia caused an increase in stroke volume of the heart, the low salinity had a more pronounced effect, causing an overall decrease in stroke volume. The patterns of haemolymph flow through the arterial system also varied when hypoxia and low salinity were offered together. The resulting responses were a mix of those resulting from exposure to either parameter alone. When low salinity and hypoxia were offered sequentially, the parameter experienced first tended to have the dominant effect on cardiac function and haemolymph flows. Low salinity exposure was associated with an increase in heart rate, a decrease in stroke volume and cardiac output, and a concomitant decrease in haemolymph flow rates. Subsequent exposure to hypoxic conditions caused a slight decrease in rate, but other cardiovascular variables were largely unaffected. In contrast, when low salinity followed acclimation to hypoxic conditions, apart from an increased heart rate, there were no other cardiovascular changes associated with the low salinity episode. The implications of these changes in cardiovascular dynamics are discussed in relation to physiological mechanisms and the ecology of decapod crustaceans, in hypoxic or low salinity environments. J. Exp. Zool. 295A:57–70, 2003. © 2003, Wiley‐Liss, Inc.
Lactic acid is absorbed from the small intestine of sheep
Authors: Ding Zhaokun , Xu Youqing 
Published: December 2002

AbstractA series of experiments was conducted in vivo on anaesthetized sheep to explore the hypothesis that lactic acid is absorbed from the small intestine of sheep. Test solutions varying in lactic acid concentration, pH, osmolarity, and with fixed physiological concentrations of volatile fatty acids (VFAs), K+, Na+, NH4+, Cl−, and PO4−3, were separately introduced into clean, surgically sealed pouches. Studies were undertaken in 27 sheep, each with three pouches in the middle of the duodenum, jejunum, and ileum. Samples were taken at 15‐minute intervals for 60 minutes to determine the absorption rates. The experimental results showed that L‐ and D‐lactic acid were absorbed from the pouches of the duodenum, jejunum, and ileum throughout the 60 minutes. In the test solutions with pH 5.3, 420mOsmol/kg, and 12.5mM lactic acid that are in vivo conditions of light lactic acidosis, the mean absorption rates of D‐lactic acid and L‐lactic acid pooled from three pouches were similar, 0.07μmol/cm2/min and 0.06μmol/cm2/min, respectively, based on absorptive surface area. The mean absorption rates of DL‐lactic acid from the duodenum, jejunum, and ileum pouches were almost the same, 0.14, 0.14, and 0.11μmol/cm2/min, respectively. The absorption of lactic acid varied depending on lactic acid concentration, and there was a curvilinear relationship between lactic acid concentration and its absorption rate. A decrease in pH and osmotic pressure resulted in significant, corresponding increases in the absorption of lactic acid (P<0.0001 and P<0.05, respectively). J. Exp. Zool. 295A:29–36, 2003. © 2003 Wiley‐Liss, Inc.
Paracrine interactions of mammalian adipose tissue
Authors: Pond Caroline M. 
Published: December 2002

AbstractAdipose tissue develops in and/or around most lymphoid tissues in mammals and birds. Early reports of this widespread association and hypotheses for its functional basis were long ignored in the planning of in vitro studies and the interpretation of in vivo results. Biochemical studies on rodent tissues reveal many site‐specific properties of adipocytes anatomically associated with lymph nodes and omental milky spots that equip them to interact locally with lymphoid cells. The paracrine interactions are strongest for the most readily activated lymph nodes and are modulated by dietary lipids. Perinodal adipocytes contribute less than those in the large nodeless depots to whole‐body lipid supplies during fasting. Observations on wild animals show that perinodal adipose tissue is selectively conserved even in starvation but does not enlarge greatly in natural obesity. Such paracrine provisioning of peripheral immune responses improves their efficiency and emancipates activated lymphocytes from competition with other tissues for blood‐borne nutrients. The relationship is found in extant protherians and metatherians, so it almost certainly arose early in the evolution of mammals, possibly as part of the metabolic reorganisation associated with homeothermy, viviparity, and lactation. Prolonged disruption to paracrine interactions between lymphoid and adipose tissue may contribute to the HIV‐associated adipose redistribution syndrome, causing selective hypertrophy of the mesentery, omentum, and other adipose depots that contain much activated lymphoid tissue. Skeletal and cardiac muscle may also have paracrine relationships with anatomically associated adipose tissue, but interactions between contiguous tissues have not been demonstrated directly. J. Exp. Zool. 295A:99–110, 2003. © 2003 Wiley‐Liss, Inc.
Theoretical Model for the One‐Dimensional Temperature and Stress Calculation of Simple Hot Plate Welded Geometries
Authors: Potente Helmut , Schnieders Joachim , Bornemann Markus 
Published: December 2002

AbstractIn the field of hot plate welding, experimental investigations show that the stress cracks are caused by inherent stresses in the component, which are induced in the part while it is being heated on the tool. For the better understanding of the process parameters and their effects on the phenomenon of stress cracking, a simple theoretical model for the calculation of the temperature and the stress field is to be developed. The application of the presented method shows the effects of the process parameters on the phenomenon of stress cracking and correlates with the experimental results of further investigations.
Theoretical stress distribution.magnified imageTheoretical stress distribution.
Serine protease inhibitor‐E2 (SERPINE2) is differentially expressed in granulosa cells of dominant follicle in cattle
Authors: Bédard Julie , Brûlé Sophie , Price Christopher A. , Silversides David W. , Lussier Jacques G. 
Published: December 2002

AbstractThe objective was to analyze gene expression in bovine granulosa cells of the dominant follicle by mRNA differential display. Total RNA was extracted from granulosa cells of ≤4 mm follicles, day 5 (D5) dominant follicles, and hCG‐induced preovulatory follicles. A differentially expressed cDNA observed in the dominant follicle group was used to screen a granulosa cell cDNA library, which resulted in the cloning of a 2,096 bp cDNA. Amino acid comparison showed identity level of 91.4, 83.9, and 83.1% when compared to human, rat, and mouse serine protease inhibitor E2, SERPINE2, also called Glia‐derived nexin or protease Nexin‐1. A single transcript of 2.4 kb was shown to be differentially expressed in different bovine tissues. Immunoblotting with a specific antibody raised against a fragment of SERPINE2 (S12‐R196) showed that SERPINE2 migrated at 47.5 kDa in support of glycosylation. Primordial, primary, and secondary pre‐antral follicles showed immunostaining associated with granulosa cells and oocytes, and strong labeling in large antral follicles was located with granulosa cells and follicular fluid. Heterogeneity of SERPINE2 labeling was observed in CL. Semi‐quantitative real‐time fluorescent RT‐PCR showed a six‐fold increase (P = 0.0002) in mRNA level of SERPINE2 in granulosa cells of D5 dominant follicle compared to granulosa cells collected from the ≤4 mm or preovulatory hCG‐induced follicles. This report demonstrates that SERPINE2 mRNA is regulated in a spatio–temporal pattern with highest levels in granulosa cells of growing dominant bovine follicles, and support the hypothesis that a high expression of SERPINE2 may contribute to follicular growth whereas a decrease following hCG injection may contribute to ovulation. Mol. Reprod. Dev. 64: 152–165, 2003. © 2003 Wiley‐Liss, Inc.
Capacity of adult and prepubertal mouse oocytes to undergo embryo development in the presence of cysteamine
Authors: de Matos D.G. , Nogueira D. , Cortvrindt R. , Herrera C. , Adriaenssens T. , Pasqualini R.S. , Smitz J. 
Published: December 2002

AbstractThe present study was carried out to study de novo glutathione (GSH) synthesis and to evaluate the effect of stimulating GSH synthesis during in vitro maturation (IVM) of adult and prepubertal mouse oocytes on the embryo developmental rate. Adult (8 weeks old) and prepubertal mice (24–26 days old) were primed with 5 IU of PMSG and oocytes were retrieved from the ovary 48 hr later for IVM. After IVM (18 hr) Cumulus oocyte complexes (COC) were in vitro fertilized (IVF) and in vitro culture (IVC) in order to observe embryo development. The IVM medium was supplemented with: 0, 25, 50, 100, or 200 μM of cysteamine. To study the novo GSH synthesis, 5 mM BSO was added during IVM of adult or prepubertal oocyte. Developmental rates up to blastocyst were recorded for each group. Experiments also included a group of ovulated oocytes (in vivo matured) after priming with PMSG and HCG. After IVM of adult mice oocytes, an improvement was observed on embryo development in all the supplemented groups when compared with the untreated group (P < 0.05). No differences were observed in blastocyst rate among IVM oocytes with cysteamine and ovulated oocytes. Prepubertal IVM mouse oocytes had a lower cleavage rate compared with ovulated oocytes (P < 0.05). Cysteamine failed to improve prepubertal oocytes developmental rates (P > 0,05). 2‐cell embryos, coming from IVM prepubertal oocytes and ovulated oocytes had the same preimplantation developmental rate up to the blastocyst stage. In prepubertal, and adult oocytes an inhibition of embryo development was observed when buthionine sulfoximide (BSO), a specific inhibitor of the γ‐glutamylcysteine synthetase, was added during oocyte maturation (P < 0.01). In conclusion, an improvement in mouse embryo development was observed when cysteamine was added to the IVM medium of adult mice oocytes. In prepubertal oocytes cysteamine addition during oocyte maturation failed to improve embryo developmental rates. The presence of BSO lowered or completely blocked blastocyst development. This proves that, de novo GSH synthesis during oocyte maturation of adult and prepubertal oocytes undoubtedly plays an important role in embryo development. The improvement on oocyte competence observed in adult mice oocytes is probably related to intracellular GSH synthesis stimulated by cysteamine. Nevertheless the reason why cysteamine failed to improve prepubertal oocytes competence remains as an open question. Mol. Reprod. Dev. 64: 214–218, 2003. © 2003 Wiley‐Liss, Inc.
Co‐expression and interaction of cubilin and megalin in the adult male rat reproductive system
Authors: Van Praet Oliver , Argraves W. Scott , Morales Carlos R. 
Published: December 2002

AbstractCubilin is a peripheral membrane protein that cooperates with the endocytic receptor megalin to mediate endocytosis of ligands in various polarized epithelia. Megalin is expressed in the male reproductive tract where it has been implicated in the process of sperm membrane remodeling. A potential role for cubilin in the male reproductive tract has not been explored. Using RT‐PCR, we found that cubilin and megalin mRNAs are expressed in the efferent ducts, corpus and cauda epididymis, and proximal and distal vas deferens. Immunohistological analysis revealed that cubilin was expressed in nonciliated cells of the efferent ducts, principal cells of the corpus and cauda epididymis and vas deferens. Immunogold EM showed cubilin in endocytic pits, endocytic vesicles, and endosomes of these cells. The expression profile of cubilin in the male reproductive tract was coincident with that of megalin except in principal cells of the caput epididymis. Double immunogold labeling showed that cubilin and megalin co‐localized within the endocytic apparatus and recycling vesicles of efferent duct cells. Neither protein was found in lysosomes. Injection of RAP, an antagonist of megalin interaction with cubilin, reduced the level of intracellular cubilin in cells of the efferent ducts and vas deferens. In conclusion, cubilin and megalin are co‐expressed in cells of the epididymis and vas deferens and the endocytosis of cubilin in these tissues is dependent on megalin. Together, these findings highlight the potential for a joint endocytic role for cubilin and megalin in the male reproductive tract. Mol. Reprod. Dev. 64: 129–135, 2003. © 2003 Wiley‐Liss, Inc.
Expression and location of taurine transporters and channels in the epididymis of infertile c‐rosreceptor tyrosine kinase‐deficient and fertile heterozygous mice
Authors: Xu Y.‐X. , Wagenfeld A. , Yeung C.‐H. , Lehnert W. , Cooper T.G. 
Published: December 2002

AbstractDefective sperm volume regulation causes infertility in c‐rosknockout (KO) mice lacking the initial segment of the epididymis (IS). As taurine is in high concentration in the male tract and acts as an organic osmolyte in somatic cells, the taurine transporter (TauT), taurine content and taurine channel phospholemman (PLM) were examined in the epididymides of these and fertile heterozygous (+/−) mice. TauT and PLM genes were demonstrated by RT‐PCR in the caput of +/− and c‐rosknockout males. Northern blots revealed one transcript ofTauT(8 kb) in all regions with different expression between segments (cauda > corpus > IS > caput) and no differences in expression between genotypes. Western blotting revealed three translation products of TauT in all epididymal regions (107, 69, 49 kDa) with higher expression of the 69 kDa and 49 isoforms in the −/− than +/− caput. Immunohistochemical staining revealed staining of principal cells and stronger staining of apical and clear cells in all epididymal regions. The expression of the PLM transcript (0.75 kb: cauda = corpus > caput > IS) was upregulated in the proximal caput and cauda of KO mice. Tissue taurine was higher in the cauda >corpus>IS ≅ caput in fertile males and significantly higher in the proximal caput of the KO male. By contrast, taurine concentrations in cauda epididymidal fluid and content per 106sperm did not differ between genotypes. TauT and PLM may be involved in taurine regulation in the normal epididymis and the proximal accumulation of taurine in the infertile males. Mol. Reprod. Dev. 64: 144–151, 2003. © 2003 Wiley‐Liss, Inc.
Effects of acute amitriptyline administration on memory, anxiety and activity in male and female mice
Authors: Parra Andrés , Everss Estrella , Monleón Santiago , Vinader‐Caerols Concepción , Arenas M. Carmen 
Published: December 2002

AbstractThe effects of acute administration of amitriptyline on memory consolidation in male and female CD1 mice were investigated. Three doses of this tricyclic antidepressant (7.5, 15 and 30 mg/kg) were administered immediately after inhibitory avoidance training. Forty‐five minutes after injection, subjects explored the elevated plus‐maze for five minutes. Subjects were tested for avoidance twenty‐four hours later. Amitriptyline impaired inhibitory avoidance consolidation at doses 7.5, 15 and 30 mg/kg in males, and at doses 7.5 and 30 mg/kg in females. In the elevated plus‐maze, amitriptyline had no effect on anxiety (percentage of open arm entries) and induced a dose‐dependent impairment of activity (number of closed arm entries). The observed sex differences were limited to subtle stronger effects of amitriptyline in males than in females on inhibitory avoidance. These results indicate that acute amitriptyline administration produces retrograde amnesia on inhibitory avoidance, which does not seem be mediated by anxiolytic effects.