bluuebunny/crossref_metadata_2025 huggingface dataset:
Plant Cell Culture, Effect on Growth and Secondary Product Accumulation of Organic Compounds and Surfactants
Authors: Scragg Alan
Published: July 2003

Solvent Addition

Artificial Accumulation Sites

Two Phase Cultures

Addition of Surfactants

Bibliography

A range of compounds not normally used in culture media has been added to plant‐cell cultures to improve growth or secondary product accumulation. These compounds have included solvents, ion‐exchange resins, surfactants, and perfluorocarbons. Many of these compounds have been added to increase the accumulation of secondary products in plant‐cell cultures. One approach has been to reduce the feedback inhibition upon secondary product accumulation by removing the secondary products from the cells as they are formed. Once synthesized, secondary products can be released into the medium but more frequently they are stored in the vacuole. Thus to release these compounds, the the tonoplast and cell membrane have to be crossed. Chemical agents, including organic solvents and detergents, have been used to permeabilize cells (1). Table 1 gives the concentrations of some agents required to extract 90% of the stored secondary product. For dimethyl sulfoxide (DMSO) and chloroform, the levels required can be high. In almost all cases, the viability of the cells was low after treatment which resulted in the loss of the culture or a considerable reduction in productivity.
Plant Cell Cultures, Physiochemical Effects on Growth
Authors: Scragg Alan H.
Published: July 2003

Introduction

Light

pH

Temperature

Dissolved Oxygen

Osmotic Pressure

Foam

Agitation

Bibliography
Receptors and Cell Signaling, Intracellular Receptors—Steroid Hormones and NO
Authors: Diamond Scott L.
Published: July 2003

Introduction

Steroids and their Biosynthesis

Steroid Receptors and Gene Regulation

Nitric Oxide and Nitric Oxide Synthase

Nitric Oxide: cGMP‐Dependent Signaling

Nitric Oxide: cGMP‐Independent Signaling

Nitric Oxide, Peroxynitrite, and Nitrotyrosine

Crosstalk between Nitric Oxide and Steroid Signaling

Summary: Relevance to Biotechnology

Acknowledgments

Bibliography
Unique Microcapsule Toner Synthesized by Liquid Phase Separation
Authors: Teshima K.
Published: July 2003

The specific design of microcapsules by liquid‐phase separation on organic solvents is enabled using a method for the selection of wall materials and solvents based on solubility parameters and, finally, molecular structures of raw material candidates. The feasibility of the method is demonstrated by the fabrication of a microcapsule toner called “curlfit toner”, whose superior surface coverage properties over conventional toners are demonstrated by enlargements juxtaposed in the Figure.
Hot‐Pressed Glass Matrix Composites Containing Pyrochlore Phase Particles for Nuclear Waste Encapsulation
Authors: Boccaccini A.R. , Atiq S. , Grimes R.W.
Published: July 2003

As alternative immobilization materials for Pu‐bearing nuclear waste, lead‐containing glass matrix composites with homogeneously distributed lanthanum zirconate pyrochlore particles (up to 30 % by volume) have been developed. Fabrication by hot pressing at the relatively mild temperature of 610 °C leaves the pyrochlore structure of the La zirconate unchanged, which is crucial for the containment of radioactive nuclei. The Figure, an SEM image of a polished sample with 30 % La2Zr2O7, demonstrates the homogeneous particle distribution and absence of pores.
Calcium Phosphate Glass‐Ceramics for Bioactive Coating on a β‐Titanium Alloy
Authors: Kasuga T. , Nogami M. , Niinomi M.
Published: July 2003

The formation of a porous coating is the decisive feature for the bio‐compatibility of silica‐free calcium phosphate glass ceramics on alloy surfaces like the β‐Ti structured Ti‐29Nb‐13Ta‐4.6Zr used in this work. The ceramic composition is highly important: 50 CaO‐40 P2O5‐7 Na2O‐3 TiO2 glass powder produces a pore‐free coating unable to bind hydroxyapatite, whereas 60 CaO‐30 P2O5‐7 Na2O‐3 TiO2 glass incorporates pores from which a crystalline hydroxyapatite phase can grow over the surface from simulated body fluid (see Figure).
Wrought Ni‐Base Superalloys for Steam Turbine Applications beyond 700 °C
Authors: Rösler J. , Götting M. , Del Genovese D. , Böttger B. , Kopp R. , Wolske M. , Schubert F. , Penkalla H.‐J. , Seliga T. , Thoma A. , Scholz A. , Berger C.
Published: July 2003

The development of a new steam turbine generation for use in advanced coal fired power plants with prospective operating temperatures beyond 700 °C and a projected thermodynamic efficiency of about 55 % requires, amongst other innovations, the partial substitution of ferritic steels by wrought Ni‐base superalloys. Although Ni‐base alloys are already widely used in the aerospace industry, they are faced with demands regarding component size and operation temperature, which by far exceed current aero‐engine requirements. In this article, the potential of selected alloys for 700 °C steam turbine applications is discussed with respect to their manufacturability and mechanical performance. Hereby, the focus is on the steam turbine rotor, which probably is the most critical component. It is concluded that material solutions are available for operation conditions around 600 °C but not for temperatures of 700 °C and above. Based on these results, alloy development strategies are suggested in order to close this gap and two new alloys, DT 706 and DT 750, are introduced.
Colobomatous macrophthalmia with microcornea syndrome: Report of a new pedigree
Authors: Toker Ebru , Elcioglu Nursel , Ozcan Eda , Yenice Ozlem , Ogut Mehdi
Published: July 2003

Colobomatous macrophthalmia with microcornea syndrome (MIM 602499) is a very rare eye malformation. To date, only two families with a total number of eight patients have been reported. We report on 13 additional cases in a single three‐generation family and describe the eye findings and quantitative parameters of corneal curvature and axial ocular dimensions. All affected relatives had bilateral involvement with typical inferonasal iris coloboma, chorioretinal coloboma, microcornea, and varying degrees of axial enlargement associated with myopia. Additional findings included flatter corneal curvatures and shallower anterior chambers. Iridocorneal angle abnormalities associated with elevation of intraocular pressure were detected in three patients. The pedigree confirms the autosomal dominant pattern of inheritance with complete penetrance. © 2003 Wiley‐Liss, Inc.
Beare‐Stevenson syndrome: Two south american patients with FGFR2 analysis
Authors: Vargas Rosa Andrea Pardo , Maegawa Gustavo Henrique Boff , Taucher Silvia Castillo , Leite Júlio César L. , Sanz Patricia , Cifuentes Juan , Parra Mauro , Muñoz Hernán , Maranduba Carlos Magno , Passos‐Bueno Maria R.
Published: July 2003

We report two patients with Beare‐Stevenson syndrome. This syndrome presents craniosynostosis with or without clover‐leaf skull, craniofacial anomalies, cutis gyrata, acanthosis nigricans, prominent umbilical stump, furrowed palms and soles, genital and anal anomalies. Both female newborn patients presented at birth with craniofacial anomalies, variable cutis gyrata in forehead and preauricular regions, prominent umbilical stump and anogenital anomalies. Furrowed palms and soles were also observed. The radiologic examination showed a cloverleaf‐form craniosynostosis. Chromosomes were normal. They were born with respiratory distress and were connected to mechanical ventilation for ventilatory support. Both of them died in 50 days after birth due to secondary complications. The molecular analysis of these patients identified the mutation Tyr375Cys in the FGFR2 gene. © 2003 Wiley‐Liss, Inc.
Characterization of a Wilms tumor in a 9‐year‐old girl with trisomy 18
Authors: Anderson Carol E. , Punnett Hope H. , Huff Vicki , de Chadarévian Jean‐Pierre
Published: July 2003

This is a report of a trisomy 18 patient who developed Wilms tumor in conjunction with perilobar nephroblastomatosis (NB) at 9 years and 5 months of age. Review of the literature revealed that most patients with trisomy 18 who develop Wilms tumor, do so at a later than expected age for a tumor related to NB, and are females. In this case, no chromosome 11 WT1 mutation was detected by PCR/SSCP analysis, but the tumor had in addition to the trisomy, an isochromosome 7q and loss of heterozygosity at 16q, two mutations that have been linked independently to Wilms tumorigenesis. © 2003 Wiley‐Liss, Inc.
Linkage study between congenital cataracts and five crystallin loci
Authors: Barr Cathy L. , Levin Alex V. , Kovacs Ronald , Muller Werner , Barsoum‐Homsy Magda , Zachary Dalila , Clark Rakia A. , Tsilfidis Catherine
Published: July 2003

Congenital cataracts are a common cause of preventable blindness in children. We studied autosomal dominant congenital cataracts in 38 families and examined linkage between cataract loci and the crystallin genes on chromosomes 2, 11, 17, 21, and 22. We used clinical information to group families with phenotypically similar cataracts and analyzed the genetic data in these groups. Although LOD scores > 3.0 were not obtained, we found some support for linkage to four of the chromosomal regions examined, namely 2q33‐35, 17q11.2‐12, 21q22.3, and 22q11.2. © 2003 Wiley‐Liss, Inc.
Preimplantation genetic diagnosis for a known cryptic translocation: Follow‐up clinical report and implication of segregation products
Authors: McKenzie L.J. , Cisneros P.L. , Torsky S. , Bacino C.A. , Buster J.E. , Carson S.A. , Simpson J.L. , Bischoff F.
Published: July 2003

This report describes preimplantation genetic diagnosis (PGD) of a couple with a known paternally‐derived balanced cryptic translocation 46,XY.ish t(2q;17q)(210E14−,B37c1+;B37c1−,210E14+) in embryos from a couple who previously had a child with severe mental retardation and was previously described in this journal [Bacino et al., 2000]. This child inherited the unbalanced product of translocation from her father: 46,XX.ish der(2)t(2q;17q)pat(210E14−,B37c1+). The couple desired a normal offspring and sought PGD to avoid clinical pregnancy termination. They were treated three times with in vitro fertilization followed by PGD. Two sequential FISH hybridizations were performed. In the first hybridization, telomeric probes to 2q and 17q and a chromosome 17 centromere probe were employed. The second hybridization screened for maternal age‐related aneuploidy (X,Y,13,18,21). Of the 18 informative embryos, only 4 (22%) were normal. The remaining 12 (67%) were abnormal; most with unbalanced products (10/12) from the paternally‐derived rearrangement. The most frequent mode of segregation observed for this cryptic translocation was adjacent‐1 (7/18, 39%). This suggests cryptic translocations are amenable to PGD and, as are traditional translocations, demonstrate higher frequencies of unbalanced segregants than the empiric risk of 10–15% observed at amniocentesis or chorionic villus sampling. Thus, cryptic translocations presumably behave like overt translocations, in that PGD must be performed on a relatively large number of embryos to assure even 2–3 transferable embryos. © 2003 Wiley‐Liss, Inc.
Clinical and molecular analysis of Grebe acromesomelic dysplasia in an Omani family
Authors: Al‐Yahyaee Said Ali S. , Al‐Kindi Mohammed Nasser , Habbal Omar , Kumar Dilip Sankhla
Published: July 2003

Grebe syndrome is a rare autosomal recessive acromesomelic dysplasia. The syndrome was studied clinically, radiographically, and genetically in an Omani family with four affected children. The affected persons had normal axial skeletons, severely shortened, and deformed limbs with severity increasing in a proximo‐distal gradient, and subluxated joints. The humeri and femora were hypoplastic with distal malformations. The radii/ulnae were shortened and deformed whereas carpal bones were invariably rudimentary or absent. The tibiae appeared rudimentary; fibulae were absent in two children, and some tarsal and metatarsal bones were absent. The proximal and middle phalanges were absent while the distal phalanges were present. The father and mother had short first metacarpal and middle phalynx of the fifth finger and hallux valgus respectively. Transition A1137G and deletion delG1144 mutations in the gene encoding the cartilage‐derived morphogenetic protein‐1 (CDMP‐1) were identified in this family. The A1137G is a silent mutation coding for lysine, whereas the delG1144 predicts a frameshift mutation resulting in a presumable loss of the CDMP‐1 biologically active carboxy‐terminal domain. The affected siblings were homozygous for the delG1144 mutation while parents were heterozygous. © 2003 Wiley‐Liss, Inc.
Reply to the Comments of Gillespie and Popelier
Authors: Frenking Gernot
Published: July 2003

Ein Modell als Stein des Anstoßes: Die kürzlich veröffentlichte Besprechung des Buches Chemical Bonding and Molecular Geometry hat zwischen den Autoren und dem Rezensenten eine Diskussion über die Gültigkeit der verwendeten Modelle und die Konsistenz der Schlussfolgerungen ausgelöst.
Titelbild: Serine Octamer Reactions: Indicators of Prebiotic Relevance (Angew. Chem. 30/2003)
Authors: Takats Zoltan , Nanita Sergio C. , Cooks R. Graham
Published: July 2003

Homochiralität hat ihren Ursprung in einer Folge chemischer Reaktionen. Das Titelbild zeigt einige Beispiele für Reaktionen von Serin und seinem homochiralen Octamer. Viele dieser Reaktionen sind selektiv, die heute in lebenden Organismen vorhandenen Enantiomere (L‐Aminosäuren, D‐Zucker) entstehen bevorzugt. Die Zuschrift von R. G. Cooks et al. auf S. 3645 ff. bietet weitere Informationen zur Rolle des homochiralen Serin‐Octamers in präbiotischen Prozessen.
Patterns of PERIOD and pigment‐dispersing hormone immunoreactivity in the brain of the European honeybee (Apis mellifera): Age‐ and time‐related plasticity
Authors: Bloch Guy , Solomon Sonya M. , Robinson Gene E. , Fahrbach Susan E.
Published: July 2003

We explored the neural basis of age‐ and task‐related plasticity in circadian patterns of activity in the honeybee. To identify putative circadian pacemakers in the bee brain, we used antibodies against Drosophila melanogaster and Antheraea pernyi PERIOD and an antiserum to crustacean pigment‐dispersing hormone (PDH) known to cross‐react with insect pigment‐dispersing factors (PDFs). In contrast to previous results from Drosophila, PDH and PER immunoreactivity (‐ir) were not colocalized in bee neurons. The most intense PER‐ir was cytoplasmic, in two groups of large neurons in the protocerebrum. The number of protocerebral PER‐ir neurons and PER‐ir intensity within individual cells were highest in brains collected during subjective night and higher in old bees than in young bees. These results are consistent with previous analyses of brain per mRNA in honeybees. Nuclear PER‐ir was found throughout the brain, including the optic and antennal lobes. A single group of PDH‐ir neurons (approximately 20/optic lobe) was consistently and intensely labeled at the medial margin of the medulla, independent of age or time of day. The processes of these neurons extended to specific neuropils in the protocerebrum and the optic lobes but not to the deutocerebrum. The patterns displayed by PER‐ and PDH‐ir do not completely match any patterns previously described. This suggests that, although clock proteins are conserved across insect groups, there is no universal pattern of coexpression that allows ready identification of pacemaker neurons within the insect brain. J. Comp. Neurol. 464:269–284, 2003. © 2003 Wiley‐Liss, Inc.
Somatosensation in the superior colliculus of the star‐nosed mole
Authors: Crish Samuel D. , Comer Christopher M. , Marasco Paul D. , Catania Kenneth C.
Published: July 2003

The superior colliculus (or optic tectum in nonmammals) plays a critical role in the visual system and is essential for integrating sensory inputs to guide eye and head movements. However, what is the role of the superior colliculus (SC) in species that depend almost exclusively on touch? In this study we examined the SC of the star‐nosed mole, a subterranean mammal that, instead of using vision, explores its environment using its tactile star. The star acts like a mechanosensory eye with a central tactile fovea that is constantly shifted in a saccadic manner. Multiunit microelectrode recordings were used to determine the topography and receptive field organization of somatosensory inputs to the SC and to test for visual and auditory responses. Here we report an SC dominated by somatosensory inputs in which neurons in all layers responded to mechanosensory stimulation, forming a topographic representation of contralateral body dominated by the mechanosensory star. Receptive fields were large, and appendage representations overlapped, suggesting that the SC may use a distributed, population code to guide the saccadic movements of the mole's touch fovea. No auditory or visual responses were recorded from the SC, although neurons in the neighboring inferior colliculus responded to auditory stimuli. Layers IVb–VII were identified, and a layer superficial to IVb contained neurons that responded to somatosensory stimulation, suggesting that there are unique patterns of afferents in the star‐nosed mole's SC. J. Comp. Neurol. 464:415–425, 2003. © 2003 Wiley‐Liss, Inc.
Connexin29 and connexin32 at oligodendrocyte and astrocyte gap junctions and in myelin of the mouse central nervous system
Authors: Nagy James I. , Ionescu Andrei V. , Lynn Bruce D. , Rash John E.
Published: July 2003

The cellular localization, relation to other glial connexins (Cx30, Cx32, and Cx43), and developmental expression of Cx29 were investigated in the mouse central nervous system (CNS) with an anti‐Cx29 antibody. Cx29 was enriched in subcellular fractions of myelin, and immunofluorescence for Cx29 was localized to oligodendrocytes and myelinated fibers throughout the brain and spinal cord. Oligodendrocyte somata displayed minute Cx29‐immunopositive puncta around their periphery and intracellularly. In developing brain, Cx29 levels increased during the first few postnatal weeks and were highest in the adult brain. Immunofluorescence labeling for Cx29 in oligodendrocyte somata was intense at young ages and was dramatically shifted in localization primarily to myelinated fibers in mature CNS. Labeling for Cx32 also was localized to oligodendrocyte somata and myelin and absent in Cx32 knockout mice. Cx29 and Cx32 were minimally colocalized on oligodendrocytes somata and partly colocalized along myelinated fibers. At gap junctions on oligodendrocyte somata, Cx43/Cx32 and Cx30/Cx32 were strongly associated, but there was minimal association of Cx29 and Cx43. Cx32 was very sparsely associated with astrocytic connexins along myelinated fibers. With Cx26, Cx30, and Cx43 expressed in astrocytes and Cx29, Cx32, and Cx47 expressed in oligodendrocytes, the number of connexins localized to gap junctions of glial cells is increased to six. The results suggested that Cx29 in mature CNS contributes minimally to gap junctional intercellular communication in oligodendrocyte cell bodies but rather is targeted to myelin, where it, with Cx32, may contribute to connexin‐mediated communication between adjacent layers of uncompacted myelin. J. Comp. Neurol. 464:356–370, 2003. © 2003 Wiley‐Liss, Inc.
Distribution of transient receptor potential channels in the rat carotid chemosensory pathway
Authors: Buniel Maria C.F. , Schilling William P. , Kunze Diana L.
Published: July 2003

Glomus cells in the carotid body respond to decreases in oxygen tension of the blood and transmit this sensory information in the carotid sinus nerve to the brain via neurons in the petrosal ganglion. G‐protein‐coupled membrane receptors linked to phospholipase C may play an important role in this response through the activation of the cation channels formed by the transient receptor potential (TRP) proteins. In the present study, expression of TRPC proteins in the rat carotid body and petrosal ganglion was examined using immunohistochemical techniques. TRPC3, TRPC4, TRPC5, TRPC6, and TRPC7 were present in neurons throughout the ganglion. TRPC1 was expressed in only 28% of petrosal neurons, and of this population, 45% were tyrosine hydroxylase (TH)‐positive, accounting for essentially all the TH‐expressing neurons in the ganglion. Because TH‐positive neurons project to the carotid body, this result suggests that TRPC1 is selectively associated with the chemosensory pathway. Confocal images through the carotid body showed that TRPC1/3/4/5/6 proteins localize to the carotid sinus nerve fibers, some of which were immunoreactive to an anti‐neurofilament (NF) antibody cocktail. TRPC1 and TRPC3 were present in both NF‐positive and NF‐negative fibers, whereas TPRC4, TRPC5, and TRPC6 expression was primarily localized to NF‐negative fibers. Only TRPC1 and TRPC4 were localized in the afferent nerve terminals that encircle individual glomus cells. TRPC7 was not expressed in sensory fibers. All the TRPC proteins studied were present in type I glomus cells. Although their role as receptor‐activated cation channels in the chemosensory pathway is yet to be established, the presence of TRPC channels in glomus cells and sensory nerves of the carotid body suggests a role in facilitating and/or sustaining the hypoxic response. J. Comp. Neurol. 464:404–413, 2003. © 2003 Wiley‐Liss, Inc.
Ultrastructure and synaptic targets of tectothalamic terminals in the cat lateral posterior nucleus
Authors: Kelly Larry R. , Li Jianli , Carden W. Breckinridge , Bickford Martha E.
Published: July 2003

The recent appreciation of the fact that the pulvinar and lateral posterior (LP) nuclei receive two distinct types of cortical input has sparked renewed interest in this region of the thalamus. A key question is whether the primary or “driving” inputs to the pulvinar/LP complex originate in cortical or subcortical areas. To begin to address this issue, we examined the synaptic targets of tectothalamic terminals within the LP nucleus. Tectothalamic terminals were labeled using the anterograde transport of biotinylated dextran amine (BDA) or Phaselous leucoagglutinin placed in the superior colliculus or using immunocytochemical staining for substance P, a neurotransmitter found to be used by the tectothalamic pathway (Hutsler and Chalupa [ 1991] J. Comp. Neurol. 312:379–390). Our results suggest that most tectothalamic terminals are large and occupy a proximal position on the dendritic arbor of LP relay cells. In the medial LP, tectothalamic terminals labeled by the transport of neuronal tracers or substance P immunocytochemistry can form tubular clusters that surround the proximal dendrites of relay cells. In a rostral and lateral subdivision of the lateral LP nucleus (LPl‐2), tectothalamic terminals form more typical glomerular arrangements. When compared with existing physiological data, these results suggest that a unique integration of tectal and cortical inputs may contribute to the response properties of LP neurons. J. Comp. Neurol. 464:472–486, 2003. © 2003 Wiley‐Liss, Inc.
Temporal and spatial distribution of activated caspase‐3 after subdural kainic acid infusions in rat spinal cord
Authors: Nottingham Stephanie A. , Springer Joe E.
Published: July 2003

The molecular events initiating apoptosis following traumatic spinal cord injury (SCI) remain poorly understood. Soon after injury, the spinal cord is exposed to numerous secondary insults, including elevated levels of glutamate, that contribute to cell dysfunction and death. In the present study, we attempted to mimic the actions of glutamate by subdural infusion of the selective glutamate receptor agonist, kainic acid, into the uninjured rat spinal cord. Immunohistochemical colocalization studies revealed that activated caspase‐3 was present in ventral horn motor neurons at 24 hours, but not 4 hours or 96 hours, following kainic acid treatment. However, at no time point examined was there evidence of significant neuronal loss. Kainic acid resulted in caspase‐3 activation in several glial cell populations at all time points examined, with the most pronounced effect occurring at 24 hours following infusion. In particular, caspase‐3 activation was observed in a significant number of oligodendroglia in the dorsal and ventral funiculi, and there was a pronounced loss of oligodendroglia at 96 hours following treatment. The results of these experiments indicate a role for glutamate as a mediator of oligodendroglial apoptosis in traumatic SCI. In addition, understanding the apoptotic signaling events activated by glutamate will be important for developing therapies targeting this cell death process. J. Comp. Neurol. 464:463–471, 2003. © 2003 Wiley‐Liss, Inc.
Xenopus laevis CB1 cannabinoid receptor: Molecular cloning and mRNA distribution in the central nervous system
Authors: Cottone Erika , Salio Chiara , Conrath Marie , Franzoni Maria Fosca
Published: July 2003

In the present research we isolated and characterized Xenopus laevis CB1 cannabinoid receptor mRNA. The CB1 coding sequence shows a high degree of identity with those of other vertebrates, mammals included, confirming that CB1 receptor is conserved over the course of vertebrate evolution. Notably, the similarity between the X. laevis CB1 sequence and that of the urodele amphibian Taricha granulosa is not higher than the similarity existing between Xenopus and mammals, thus supporting phylogenetic distance between anurans and urodeles. By means of in situ hybridization histochemistry, CB1 mRNA expression and distribution was investigated in the X. laevis central nervous system. As revealed, CB1 mRNA‐containing neurons are numerous in the prosencephalon, especially in the olfactory bulbs, telencephalic pallium, and hypothalamus. In the midbrain and hindbrain, labeled cells were observed in the mesencephalic tegmentum and dorsolateral romboencephalon. Abundant CB1 mRNA positive neurons are localized throughout the gray matter of the spinal cord, in particular in the dorsal and ventral fields, where labeled motor neurons are also observed. The distribution of CB1 mRNA in the Xenopus CNS is generally consistent with the CB1‐like‐immunohistochemistry results we have previously obtained, showing in amphibians a well developed cannabinergic system almost comparable to that described in mammals. However, some differences, such as the abundance of CB1 mRNA‐containing neurons in the olfactory system and the rich CB1 spinal innervation, are found. J. Comp. Neurol. 464:487–496, 2003. © 2003 Wiley‐Liss, Inc.
GABA‐ and glycine‐like immunoreactivity in axons and dendrites contacting the central terminals of rapidly adapting glabrous skin afferents in rat spinal cord
Authors: Watson Alan H.D.
Published: July 2003

The object of the present study was to determine the nature and distribution of synaptic contacts on the terminals of rapidly adapting mechanosensory afferents innervating the glabrous skin of the rat foot. Afferents were physiologically characterized by intracellular recording, before injection with neurobiotin and preparation for electron microscopy. Axon terminals were serially sectioned and immunolabeled with antibodies against GABA and glycine using a postembedding immunogold method. Afferent boutons in lamina III were often surrounded by several presynaptic axons and postsynaptic dendrites (thus forming type II glomeruli), while boutons in laminae IV–V had only simple, nonglomerular interactions. In both regions triadic synaptic arrangements where presynaptic interneurons contact both afferent boutons and their postsynaptic dendrites were present in 50–75% of boutons. Approximately three‐quarters of presynaptic axons were immunoreactive for both GABA and glycine and most of the remainder for GABA alone. Most postsynaptic dendrites were not immunoreactive. Comparisons are made with information from similar studies of other rat and cat afferents conducting in the Aαβ range. This demonstrates that although the principles of control may be similar for cutaneous afferents of this type there are significant differences between cutaneous and 1a muscle afferents in the rat. There are also differences in detail between the interactions of afferents of the same modality in rat and cat; in the rat there are greater numbers of presynaptic axons per bouton and a greater proportion of boutons receive axo‐axonic contacts and are involved in synaptic triads. J. Comp. Neurol. 464:497–510, 2003. © 2003 Wiley‐Liss, Inc.
Comparative distribution of neuropeptide Y Y1 and Y5 receptors in the rat brain by using immunohistochemistry
Authors: Wolak Michael L. , deJoseph M. Regina , Cator Allison D. , Mokashi Ashwini S. , Brownfield Mark S. , Urban Janice H.
Published: July 2003

Neuropeptide Y (NPY) Y1 and Y5 receptor subtypes mediate many of NPY's diverse actions in the central nervous system. The present studies use polyclonal antibodies directed against the Y1 and Y5 receptors to map and compare the relative distribution of these NPY receptor subtypes within the rat brain. Antibody specificity was assessed by using Western analysis, preadsorption of the antibody with peptide, and preimmune serum controls. Immunostaining for the Y1 and Y5 receptor subtypes was present throughout the rostral‐caudal aspect of the brain with many regions expressing both subtypes: cerebral cortex, hippocampus, hypothalamus, thalamus, amygdala, and brainstem. Further studies using double‐label immunocytochemistry indicate that Y1R immunoreactivity (‐ir) and Y5R‐ir are colocalized in the cerebral cortex and caudate putamen. Y1 receptor ir was evident in the central amygdala, whereas both Y1‐ and Y5‐immunoreactive cells and fibers were present in the basolateral amygdala. Corresponding with the physiology of NPY in the hypothalamus, both Y1R‐ and Y5R‐ir was present within the paraventricular (PVN), supraoptic, arcuate nuclei, and lateral hypothalamus. In the PVN, Y5R‐ir and Y1R‐ir were detected in cells and fibers of the parvo‐ and magnocellular divisions. Intense immunostaining for these receptors was observed within the locus coeruleus, A1–5 and C1–3 nuclei, subnuclei of the trigeminal nerve and nucleus tractus solitarius. These data provide a detailed and comparative mapping of Y1 and Y5 receptor subtypes within cell bodies and nerve fibers in the brain which, together with physiological and electrophysiological studies, provide a better understanding of NPY neural circuitries. J. Comp. Neurol. 464:285–311, 2003. © 2003 Wiley‐Liss, Inc.
Proposed parameters for monitoring quality of virgin olive oil (Koroneiki cv)
Authors: Psomiadou Eleni , Karakostas Konstantinos X. , Blekas Georgios , Tsimidou Maria Z. , Boskou Dimitrios
Published: July 2003

The overall quality of virgin olive oil (VOO) is closely related to its oxidative stability that is usually evaluated through the stability index measured by the Rancimat apparatus. Quality characteristics and also pro‐oxidant and antioxidant content for 52 Greek VOO samples (Koroneiki cv) were used to build up a model capable of predicting stability. Collinearity diagnostics, variable selection, and regression analysis were applied to the experimental data to locate the contribution of each parameter to the keeping quality of the samples. The predictive ability of the model was confirmed for a second VOO ample set of the same cultivar. It was found that except for the peroxide value, which negatively influences the stability, other important parameters were α‐tocopherol, total polar phenol and total chlorophyll content. It is concluded that the colorimetric determination of total polar phenols, the spectrometric determination of total chlorophylls and the high‐performance liquid chromatography analysis of α‐tocopherol, not presently included in the established methods of official analysis, can be used for a better evaluation of VOO quality. These parameters, which can be easily adopted as routine methods by the industry, seem to be of utmost importance for shelf life prediction and expiration dating if applied for the promotion of the most competitive products in the international olive oil market.
Epoxidation of a conjugated linoleic acid isomer
Authors: Jie Marcel S. F. Lie Ken , Lam Corey N. W. , Ho Janette C. M. , Lau Maureen M. L.
Published: July 2003

Epoxidation of methyl (9Z, 11E)‐octadecadienoate (1) with various epoxidizing agents viz. m‐chloroperoxybenzoic acid, dimethyl dioxirane, methyltrioxorhenium/hydrogen peroxide, potassium peroxomonosulfate (Oxone, 2KHSO5 · KHSO4 · K2SO4)/tetrahydrothiopyran‐4‐one, and Novozyme 435/hydrogen peroxide is described. The reactions furnished the corresponding mono‐epoxy [methyl (11, 12E)‐epoxy‐(9Z)‐octadecenoate (2) and methyl (9, 10Z)‐epoxy‐(11E)‐octadecenoate (3)] and a mixture of diastereomers of syn‐ and anti‐diepoxy‐stearate [methyl (9, 10Z;11, 12E)‐diepoxystearate (4a‐4d)], which were identified by a combination of spectroscopic and spectrometric analyses.
A personal and provocative view on the European GMO situation
Authors: Leysen Roger J. F.
Published: July 2003

The author was, during his active career with the American Soybean Association in Brussels (Belgium), a direct witness when the GMO soybeans were first announced and introduced in the EU market. He reviews the responsibility of the different parties involved and expresses his personal opinion about the errors made during the initial phase. He specifically expresses his worries with regard to the unworkable, legislative situation in the EU.
Fast enantiomeric separation with vancomycin as chiral additive by co‐electroosmotic flow capillary electrophoresis: Increase of the detection sensitivity by the partial filling technique
Authors: Kang Jingwu , Wistuba Dorothee , Schurig Volker
Published: July 2003

A fast and sensitive method is described by using vancomycin as a chiral additive for enantiomeric separation by capillary electrophoresis (CE). In order to overcome disadvantages associated with use of vancomycin as chiral additive in CE, several strategies including the dynamic coating technique, the co‐electroosmotic flow technique, and the partial filling technique were employed sequentially in this method. Using the polycationic polymer hexadimethrine bromide (HDB) as a buffer additive, the capillary wall was dynamically coated with a thin film formed by the adsorbed HDB. Consequently, the adsorption of vancomycin onto the capillary wall was minimized via electrostatic repulsion between the coating of the capillary wall and the vancomycin molecule. In addition, the reversed electroosmotic flow (from cathode to anode) produced by the positively charged capillary wall migrates in the same direction of negatively charged analytes (co‐electroosmotic flow electrophoresis). Thereby the electrophoretic mobility of negatively charged analytes were drastically accelerated leading to a short separation time of less than 3.4 min. The separation time was further reduced by the use of a short‐end‐injection technique. For example, the analysis time was achieved by as short as 55 s for a baseline separation of dansyl‐α‐amino‐n‐butyric acid. Concurrently, the partial filling technique was used to avoid the loss of detection sensitivity caused by the presence of vancomycin in the running buffer. The effect of several parameters, such as HDB concentration, buffer pH, plug length of the chiral selector, concentration of the chiral selector and applied voltage, on enantioselectivity were investigated toward optimization. Besides the advantage of a very short separation time, the method is characterized by high detection sensitivity, high selectivity, and high efficiency.
Cyclodextrin‐modified monolithic columns for resolving dansyl amino acid enantiomers and positional isomers by capillary electrochromatography
Authors: Chen Zilin , Ozawa Hiroshi , Uchiyama Katsumi , Hobo Toshiyuki
Published: July 2003

We describe β‐ and γ‐cyclodextrins (β‐ and γ‐CD)‐modified monolithic columns prepared by sol‐gel process and chemical modifications. The monolithic silica column was fabricated inside a fused‐silica capillary with 100 μm inner diameter by sol‐gel process. The monolithic silica matrix was chemically modified chiral selectors of β‐ or γ‐CDs with a spacer of 3‐glycidoxypropyltrimethoxysilane by on‐column reactions. γ‐CD‐modified monolithic column has successfully been applied for the separation of dansyl amino acid enantiomers. β‐CD‐modified monolithic column has been used for the separation of the positional isomers of o‐, m‐, and p‐cresols and the enantioseparation of racemates of benzoin and several dansyl amino acids by capillary electrochromatography, respectively. For the separation of neutral positional isomers, a positive electric field was applied. However, for the separation of negatively charged analytes, a negative electric field was applied at the inlet of column. The separation efficiency of 5.0×104 theoretical plates/m for dansyl‐L‐threonine was obtained at electric field strength of −300 V/cm in the mobile phase of 50 mM 2‐(N‐morpholino)ethanesulfonic acid (MES)‐Tris/methanol (70/30) buffer at pH 7.0. L‐Enantiomers were eluted as the first peak. Scanning electron micrograph showed that monolithic columns have the morphology of continuous skeleton and large through‐pores.
Direct chiral resolution of tartaric acid by ion‐pair capillary electrophoresis using an aqueous background electrolyte with (1R,2R)‐(–)‐1,2‐diaminocyclohexane as a chiral counterion
Authors: Kodama Shuji , Yamamoto Atsushi , Matsunaga Akinobu , Hayakawa Kazuichi
Published: July 2003

Chiral resolution of native DL‐tartaric acid was achieved by ion‐pair capillary electrophoresis (CE) using an aqueous‐ethanol background electrolyte with (1R,2R)‐(−)‐1,2‐diaminocyclohexane (R‐DACH) as a chiral counterion. Factors affecting chiral resolution and migration time of tartaric acid were studied. By increasing the viscosity of the background electrolyte and the ion‐pair formation, using organic solvents with a lower relative dielectric constant, resulted in a longer migration time. The optimum conditions for both high resolution and short migration time of tartaric acid were found to be a mixture of 65% v/v ethanol and 35% v/v aqueous solution containing 30 mM R‐DACH and 75 mM phosphoric acid (pH 5.1) with an applied voltage of −30 kV at 25°C, using direct detection at 200 nm. By using this system, the resolution (Rs) of racemic tartaric acid was approximately 1. The electrophoretic patterns of tartaric and malic acids suggest that two carboxyl groups and two hydroxyl groups of tartaric acid are associated with the enantioseparation of tartaric acid by the proposed CE method.
Separation of aminoalkanephosphonic acid enantiomers by indirect UV detection capillary electrophoresis with application of cyclodextrins
Authors: Rudzińska Ewa , Wieczorek Piotr , Kafarski Paweł
Published: July 2003

Indirect UV detection capillary electrophoresis (CE) was used for the separation of aminoalkanephosphonic acid (AP) enantiomers by applying commercially available cyclodextrins as chiral discriminators. The results show that the separation of the enantiomers depends on pH of the background electrolyte, the molar ratio of cyclodextrin to aminophosphonic acid, and on the type of the applied chiral selector. Optimization of process conditions allowed enantiomeric baseline separation or partial separation of 12 out of 14 α‐aminophosphonic acids studied. This type of CE might therefore be successfully used for routine determination of enantiomeric purity of aminophosphonic acids.
Simultaneous chiral discrimination of multiple profens by cyclodextrin‐modified capillary electrophoresis in normal and reversed polarity modes
Authors: La Sookie , Kim Jiyung , Kim Jung‐Han , Goto Junichi , Kim Kyoung‐Rae
Published: July 2003

Simultaneous enantioseparations of nine profens for their accurate chiral discrimination were achieved by capillary electrophoresis (CE) in the normal polarity (NP) mode with a single cyclodextrin (CD) system and in the reversed polarity (RP) mode with a dual CD system. The single CD system in the NP mode employed heptakis(2,3,6‐tri‐O‐methyl)‐β‐cyclodextrin (TMβCD) added at 75 mM–100 mM 2‐(N‐morpholino)ethanesulfonic acid buffer (pH 6.0) as the optimum run buffer. The dual CD system operated in the RP mode used 30 mM TMβCD and 1.0% anionic carboxymethyl‐β‐cyclodextrin dissolved in pH 3.0, 100 mM phosphoric acid‐triethanolamine buffer containing 0.01% hexadimethrine bromide added to reverse the electroosmotic flow. Fairly good enantiomeric resolutions and the opposite enantiomer migration orders were achieved in the two modes. Relative migration times to internal standard under respective optimum conditions were characteristic of each enantiomer with good precision (< 2% relative standard deviation, RSD), thereby enabling to crosscheck the chemical identification of profens and also their accurate chiralities. The method linearity in the two modes was found to be adequate (r ≥ 0.9991) for the chiral assay of the profens investigated. Simultaneous enantiomeric purity test of ibuprofen, ketoprofen and flurbiprofen in a mixture was feasible in a single analysis by the present method.
Use of chiral zwitterionic surfactants for enantiomeric resolutions by capillary electrophoresis
Authors: Hadley Mark R. , Harrison Mark W. , Hutt Andrew J.
Published: July 2003

The enantiomeric resolution of 1,1’‐binaphthyl‐2,2’‐diamine and Tröger’s base was investigated using the commercially available zwitterionic surfactants 3‐[(3‐cholamidopropyl)dimethylammonio]‐1‐propanesulphonate (CHAPS) and 3‐[(3‐cholamidopropyl)dimethylammonio]‐2‐hydroxy‐1‐propanesulphonate (CHAPSO). Resolution of the weakly basic chiral probes was achieved using varying concentrations of surfactant, above their critical micellar concentrations, in a phosphate buffer (pH 2.5; 100 mM) to ensure ionisation of the analytes. Both CHAPS and CHAPSO were employed in the absence of additional coselectors or surfactants as sole micellar‐forming agents. The addition of organic modifiers, methanol and acetonitrile (ACN), to the background electrolyte (BGE) was found to have a detrimental effect on enantioselectivity presumably by alteration of the phase polarity.
Study on thioridazine 5‐sulfoxide epimerization and degradation by capillary electrophoresis
Authors: Masetto de Gaitani Cristiane , Souto Martinez Alexandre , Sueli Bonato Pierina
Published: July 2003

We present a method for the stereoselective analysis of thioridazine 5‐sulfoxide (THD 5‐SO) in human plasma based on liquid‐liquid extraction with diethyl ether and chiral resolution of the stereoisomers by capillary electrophoresis using hydroxypropyl‐β‐cyclodextrin and sulfated β‐cyclodextrin as chiral selectors. The method showed recovery rates of 85.5% for both THD 5‐SO (slow‐eluting, SE) enantiomers. The coefficients of variation observed in the precision studies, as well as the accuracy values, were below 10%. After validation, the method was used to study the stability and configurational changes of this THD metabolite. Our results showed that both enantiomers of THD 5‐SO (SE) were stable under conditions of variation of temperatures (38°C, 4°C and −20°C), pH (5.0, 7.0 and 8.5) and ionic strengths (0.2, 0.5 and 1.0 mol/L). The influence of light on the stability of the THD 5‐SO (SE) stereoisomers was also studied using standard solutions prepared in methanol and an inversion in configuration was observed under UV light (254 and 366 nm).
Infinite enantiomeric resolution of basic compounds using highly sulfated cyclodextrin as chiral selector in capillary electrophoresis
Authors: Rudaz Serge , Calleri Enrica , Geiser Laurent , Cherkaoui Samir , Prat Josiane , Veuthey Jean‐Luc
Published: July 2003

Four chiral basic analytes, namely methadone, fluoxetine, venlafaxine, and tramadol, were selected as model compounds for investigating their stereoselective separation with highly sulfated γ‐cyclodextrin (HS γ‐CD) by capillary electrophoresis (CE)‐UV and CE‐mass spectrometry (MS). At high concentration of chiral selector, the preferentially bonded enantiomer migrated faster in the anodic mode to the detector and high resolutions were obtained for all analytes. In the cathodic mode, at lower highly sulphated cyclodextrin (HS‐CD) concentration, basic compounds could be detected, with the weakly bonded enantiomer migrating first (enantiomeric migration order inversion). It was also then possible, at intermediate HS‐CD concentration, that only one enantiomer migrated to the detector as cation while the other enantiomer complexed with the CD was negatively charged and presented an opposite mobility. The latter never reached the detector achieving a perfect enantiomeric selectivity. Infinite chiral resolutions were thus achieved by CE‐UV as well as by CE‐electrospray ionisation (ESI)‐MS where concentrations of HS‐CD were adapted according to the negative contribution of the nebulization gas pressure of the interface.
Chiral resolution of diastereomeric di‐ and tripeptides on a teicoplanin aglycone phase by capillary electrochromatography
Authors: Schmid Martin G. , Grobuschek Nina , Pessenhofer Verena , Klostius Andrea , Gübitz Gerald
Published: July 2003

The chiral separation ability of a capillary packed with teicoplanin aglycone as a chiral stationary phase was investigated. This stationary phase was used successfully for chiral resolution of both diastereomeric dipeptides and tripeptides possessing one or two chiral centers. The composition of the mobile phase was shown to be crucial for separation. The use of reversed‐phase mode was clearly superior to the polar‐organic mode. The nature of the organic modifier was found to have a marked influence on separation. After optimizing conditions, all diasteromeric dipeptides and tripeptides investigated were baseline‐resolved, however, it was not possible to find a uniform mobile phase showing optimal results for all peptides investigated.
Enantiomeric impurity profiling in ephedrine samples by enantioselective capillary electrochromatography
Authors: Bicker Wolfgang , Hebenstreit Dieter , Lämmerhofer Michael , Lindner Wolfgang
Published: July 2003

This study reports on the development and preliminary validation of a capillary electrochromatographic (CEC) method for the enantioselective impurity profiling of D‐ephedrine. As chiral selector a novel low‐molecular‐weight strong chiral cation exchanger, based on penicillamine sulfonic acid, immobilized on thiol‐modified silica particles (3.5 μm) was employed. Under optimized conditions, the ephedrine enantiomers were separated on this chiral stationary phase (CSP) with an enantioselectivity of 1.11, an average efficiency of 321 550 plates per meter, and a resolution value of 4.77. A preliminary method validation was carried out to demonstrate the applicability of CEC for enantiomeric excess (ee) determination. Run‐to‐run repeatabilities (n = 5) reached relative standard deviation values (RSD) of 0.18 and 0.19% for the migration times of L‐ and D‐enantiomer, respectively, 0.3% for the resolution, and about 0.9% for the peak efficiencies. An approach called self‐internal standard method was utilized to measure a standard calibration curve. Excellent linearity with a correlation coefficient of R2 = 0.9998 was found for samples with concentrations in the range between 0.03 and 5 mg·mL−1 D‐ephedrine spiked with L‐ephedrine at a constant concentration of 0.2 mg·mL−1. The high loadability of the investigated CSP and good peak sensitivity allowed us to determine less than 0.1% enantiomeric impurity with good accuracy. The limit of detection (LOD) for the L‐enantiomer in a 3 mg·mL−1 D‐ephedrine solution was found to be 0.035% (S/N = 3) and the limit of quantitation (LOQ) 0.058% (S/N = 5). For L‐ephedrine samples the strong cation‐exchange (SCX)‐type CSP with opposite configuration was utilized so that the enantiomeric impurity eluted before the main component peak yielding similar results in terms of separation and validation. Based on these results, the presented nonaqueous CEC methods are assessed as principally suitable for ee determination of ephedrine in terms of repeatability and method sensitivity.