bluuebunny/crossref_metadata_2025 huggingface dataset:
Discrete Bose‐Einstein systems in a box with low adiabatic invariant
Authors: Vlad V.I. , Ionescu‐Pallas N.
Published: April 2003

The Bose‐Einstein energy spectrum of an ideal quantum gas confined in a box is discrete and strongly dependent on the box geometry and temperature, for low product of the atomic mass number, Aat and the adiabatic invariant, TV2/3, i.e. on γ = Aat TV2/3. Even within the approximation of non‐interacting particles in the gas, the calculation of the thermodynamic properties of Bose‐Einstein systems turns out to be a difficult mathematical problem. The present study compares the total number of particles, the total energy and the specific heat obtained by sums over the discrete states to the results of the approximate integrals (for defined values of γ) and shows the noticeable errors of the last ones at low adiabatic invariant (around condensation). Then, more rigorous and precise analytical approximations of sums are found in the case of finite number of atoms (correlated with the existence of a zero energy level) and the finite volume of the gas. The corrected thermodynamic functions depend on γ (for fixed fugacity). The condensation temperature is corrected also in order to describe more accurately the discrete Bose‐Einstein systems. Under these circumstances, the analysis of the specific heat leads to the conclusion that it shows no discontinuity, for the entire range of γ values.
Generation of photon number states on demand
Authors: Walther H.
Published: April 2003

The widely discussed applications in quantum information and quantum cryptography require radiation sources capable of producing a fixed number of photons. This paper reviews the work performed in our laboratory to produce these fields on demand. Two different methods are discussed. The first is based on the one‐atom maser or the micromaser operating under the conditions of the so‐called trapping states. In this situation the micromaser stabilises to a photon number state. The second device uses a single ion in an optical cavity. The latter setup was recently realised in our laboratory.
Anti‐inﬂammatory and smooth muscle relaxant activities of the hydroalcoholic extract and chemical constituents from Amburana cearensis A. C. Smith
Authors: Leal L. K. A. M. , Nechio M. , Silveira E. R. , Canuto K. M. , Fontenele J. B. , Ribeiro R. A. , Viana G. S. B.
Published: April 2003

Amburana cearensis A. C. Smith, Fagaceae, is a medicinal plant commonly known as ‘cumaru’ and used in Northeast Brazil for the treatment of respiratory tract diseases. In the present work, we investigated the anti‐inﬂammatory and smooth muscle relaxant activities of the hydroalcoholic extract (HAE), coumarin (Coum) and ﬂavonoid fraction (FF) isolated from the trunk barks of Amburana cearensis A. C. Smith. It was shown that HAE (200 and 400 mg/kg), Coum (20 and 40 mg/kg) and FF (40 mg/kg), administered orally, signiﬁcantly inhibited both leukocyte and neutrophil migrations, in the carrageenan or N‐formyl‐methyl‐leucyl‐phenylalanine (fMLP)‐induced migration in rat peritoneal cavity. The increase in cutaneous vascular permeability induced by serotonin in rats was signiﬁcantly blocked by HAE (150 mg/kg, i.p.), Coum (5 mg/kg, i.p.) and FF (20 mg/kg, i.p.). However, only HAE blocked the histamine effect on Evans blue extravasation. In the guinea‐pig trachea precontracted with carbachol (0.3 µM), histamine (0.1 µM) or KCl (0.1 M), the HAE, Coum and FF evoked a concentration‐dependent relaxation in the presence of the three agonists. HAE (100–800 µg/ml) and Coum (4–32 µg/ml) also caused signiﬁcant relaxation of the rat vas deferens previously contracted with adrenaline, acetylcholine or barium chloride. In addition, HAE, Coum and FF inhibited the histamine and serotonin‐induced increase of cutaneous vascular permeability in rats. Copyright © 2003 John Wiley & Sons, Ltd.
Cytotoxic and multidrug resistance reversal activity of a vegetable, ‘Anastasia Red’, a variety of sweet pepper
Authors: Motohashi Noboru , Wakabayashi Hidetsugu , Kurihara Teruo , Takada Yuko , Maruyama Shichiro , Sakagami Hiroshi , Nakashima Hideki , Tani Satoru , Shirataki Yoshiaki , Kawase Masami , Wolfard Kristina , Molnár Joseph
Published: April 2003

The vegetable, Anastasia Red, Capsicum annuum L. var. angulosum Mill. (Solanaceae) was successively extracted with hexane, acetone, methanol and 70% methanol, and the extracts were further separated into a total of 21 fractions by silica gel or octadecylsilane (ODS) column chromatography. The biological activities of extracts and fractions were determined. These extracts showed relatively higher cytotoxic activity against two human oral tumor cell lines (HSC‐2, HSG) than against normal human gingival ﬁbroblasts (HGF), suggesting a tumor‐speciﬁc cytotoxic activity. The cytotoxic activity of these extracts was enhanced by fractionation on silica gel [H2, A2, M1–M3] or ODS column chromatography [70M]. Several fractions [H2, H4, H5, A1, A2, A3, A5, A6, A7, M2] reversed the multidrug resistance (MDR) phenotype with L5178 mouse lymphoma T cells, more efﬁciently than (±)‐verapamil. The extracts and fractions did not show any detectable anti‐human immunodeﬁciency virus (HIV) or anti‐Helicobacter pylori activity. Thus, this study suggests the effective and selective antitumor potential of ‘Anastasia Red’ of sweet pepper for further phytochemical and biological investigation. Copyright © 2003 John Wiley & Sons, Ltd.
In vitro antimicrobial efﬁcacy of leaf essential oils of Chukrasia tabularis Adr. Juss. and Melia dubia Cav. (Meliaceae)
Authors: Nagalakshmi M. A. H. , Thangadurai D. , Pullaiah T.
Published: April 2003

The essential oils of Chukrasia tabularis and Melia dubia were tested for their antimicrobial activity against ten different pathogenic microorganisms responsible for human pathologies using standard antimicrobial assays. Chukrasia tabularis leaf oil exhibited strong antibiotic activities against Proteus vulgaris and Fusarium oxysporum and did not show any activity against the tested bacteria. Melia dubia leaf essential oil exhibited bacteriostatic and fungistatic activities against Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae and Fusarium oxysporum and Candida albicans respectively. The inhibitory activities of both essential oils are comparable with that of respective standards. Copyright © 2003 John Wiley & Sons, Ltd.
Antidiarrhoeal activity of hot water extract of black tea (Camellia sinensis)
Authors: Besra S. E. , Gomes A. , Ganguly D. K. , Vedasiromoni J. R.
Published: April 2003

The effect of a hot water extract of black tea (Camellia sinensis (L.) O. Kuntze, Theaceae) on upper gastrointestinal transit and on diarrhoea was investigated employing conventional rodent models of diarrhoea. Black tea extract was found to possess antidiarrhoeal activity in all the models of diarrhoea used. Naloxone (0.5 mg/kg i.p.) signiﬁcantly inhibited the antidiarrhoeal activity of the extract as well as loperamide, thus indicating a role of the opioid system in the antidiarrhoeal activity of the extract. Copyright © 2003 John Wiley & Sons, Ltd.
Zinc co‐ordination in the DNA‐binding domain of the yeast transcriptional activator PPR1
Authors: Ball Linda J. , Diakun Gregory P. , Gadhavi Paresh L. , Young Nigel A. , Armstrong Elaine M. , David Garner C. , Laue Ernest D.
Published: April 2003

The structure of the native zinc form of the DNA binding domain in the yeast transcriptional activator PPR1 was investigated by extended X‐ray absorption fine structure (EXAFS). By carrying out the EXAFS measurements at 11k we were able to demonstrate explicitly the proximity of the two zinc ions () and the presence of bridging cysteine ligands. The results show that the six cysteine residues co‐ordinate two zinc ions in a two‐metal ion cluster. PPR1 is the first member of this class of protein for which such information has been obtained.
Location and properties of the digitalis receptor site in Na+/K+‐ATPase
Authors: Repke Kurt R.H. , Megges Rudolf , Weiland Jürgen , Schön Rudolf
Published: April 2003

Since 1985, several research groups have shown that a number of amino acids in the catalytic α‐subunit of Na+/K+‐ATPase more or less strongly modulate the affinity of a digitalis compound like ouabain to the enzyme. However, scrutiny of these findings by means of chimeric Na+/K+‐ATPase constructs and monoclonal antibodies has recently revealed that the modulatory effect of most of these amino acids does not at all result from direct interaction with ouabain, but rather originates from long‐range effects on the properties of the digitalis binding matrix. Starting from this knowledge, the present review brings together the various pieces of evidence pointing to the conclusion that the interface between two interacting α‐subunits in the Na+/K+‐ATPase protodimer (αβ)2 provides the cleft for inhibitory digitalis intercalation.
Identification of prostaglandin E receptor ‘EP2’ cloned from mastocytoma cells as EP4 subtype
Authors: Nishigaki Nobuhiro , Negishi Manabu , Honda Akiko , Sugimoto Yukihiko , Namba Tsunehisa , Narumiya Shuh , Ichikawa Atsushi
Published: April 2003

We previously cloned a cDNA for a mouse PGE receptor positively coupled to adenylate cyclase from mouse mastocytoma cells, and reported it as EP2 subtype of PGE receptor [Honda, A., Sugimoto, Y., Namba, T., Watabe, A., Irie, A., Negishi, M., Narumiya, S. and Ichikawa, A. (1993) J. Biol. Chem. 268, 7759–7762]. However, it is not sensitive to one of the EP2 agonists, butaprost. Recently another subtype of PGE receptor coupled to adenylate cyclase has been identified pharmacologically and named EP4. These findings have led us to examine whether the cloned receptor is the EP4 subtype. AH23848B, a selective EP4 antagonist, not only displaced the [3H]PGE2 binding to the cloned receptor but antagonized the PGE2‐stimulated cAMP formation in the receptor. In contrast, EP2 specific agonists, butaprost and 19(R)OH‐PGE2 neither bound to the receptor nor stimulated the cAMP formation. These results suggest that this receptor previously reported as ‘EP2’ subtype is identical to the pharmacologically defined EP4 subtype and not of EP2 subtype.
Detection of Ca2+‐transients elicited by flash photolysis of DM‐nitrophen with a fast calcium indicator
Authors: Escobar Ariel L. , Cifuentes Fredy , Vergara Julio L.
Published: April 2003

A confocal spot detection optical setup was used to record fluorescence signals in response to calcium pulses, elicited by flash photolysis of DM‐nitrophen, with the calcium indicators CaOrange‐5N and Fluo‐3. Our results yield the following conclusions: [Ca2+] changes are almost perfect spikes at pCa 9 and broader transients followed by a step at pCa 7. The [Ca2+] spikes were used to measure the dissociation rate constant of the Ca2+ dyes. Experiments at pCa 7 were used to verify the kinetic rate constants of the dyes and to obtain those of DM‐nitrophen. The association rate constant of this compound was found to be more than one order of magnitude faster than that suggested previously. CaOrange‐5N was able to track changes in [Ca2+] more accurately than Fluo‐3. This latter dye introduced severe distortions which preclude a quantitative deconvolution of the fluorescence transients into changes in the free [Ca2+].
Unusual long target duplication by insertion of intracisternal A‐particle element in radiation‐induced acute myeloid leukemia cells in mouse
Authors: Tanaka Izumi , Ishihara Hiroshi
Published: April 2003

Retrotransmission into the IL‐3/GM‐CSF gene locus by the retrotransposon intracisternal A‐particle (IAP) had been observed in distinct tumor cell lines. We analyzed the locus in genomes from 7 different myeloid leukemia cell strains which were originally generated by whole‐body X‐irradiation of the inbred C3H/He mice at a dose of 3 Gy and maintained by in vivo passage. In one leukemia cell strain out of 7 such cases, RFLP of an allele of the interleukin‐3 gene was found. Sequence analysis after cloning from the genomic library showed that a type IΔ2 IAP element was inserted in the region upstream of the IL‐3 gene in the head‐to‐head orientation. This suggests that the locus in myeloid cells is sensitive for integration of IAP elements. Additionally, an unusual long target duplication of 82 bp, 14‐fold larger than normal one, was found at the junction of the element. This suggests the possibility of a radiation‐induced integration mechanism which is distinct from normal retrotransmission.
The N‐terminal, dehydrogenase/cyclohydrolase domain of yeast cytoplasmic trifunctional C1‐tetrahydrofolate synthase requires the C‐terminal, synthetase domain for the catalytic activity in vitro
Authors: Song Jae Mahn , Rabinowitz Jesse C.
Published: April 2003

The yeast ADE3(1–333) gene which encodes a truncated protein containing the N‐terminal 5,10‐methylene‐tetrahydrofolate (THF) dehydrogenase (D)/5,10‐methynyl‐THF cyclohydrolase (C) domain of cytoplasmic trifunctional C1‐THF synthase is able to complement all the phenotypes associated with ade3 mutations in vivo. However, expression of the ADE3(1–333) gene in an ade3 strain does not retain any D activity in vitro. Expression in a yeast ade3 strain of the ADE3(1–333) fused to the Escherichia coli lacZ gene or to the yeast SER2 gene allows detection of D and C activities in vitro. These results indicate that the N‐terminal D/C domain of C1‐THF synthase requires the C‐terminal 10‐formyl‐THF synthetase domain for stable catalytic activity in vitro.
Secondary structure of an armadillo single repeat from the APC protein
Authors: Hirschl Daniela , Bayer Peter , Müller Oliver
Published: April 2003

The armadillo domain is a repeating sequence motif of a variety of proteins with different functions. Here we describe the structure of a synthetic single armadillo repeat solved by two‐dimensional nuclear magnetic resonance spectroscopy. Our results indicate α‐helical secondary structural elements in half of the residues.
Expression of urokinase‐type plasminogen activator, its receptor and type‐1 plasminogen activator inhibitor is differently regulated by inhibitors of protein synthesis in human cancer cell lines
Authors: Lund Leif R.
Published: April 2003

Expression of the various components of the plasminogen activation system is under tight regulation by hormones, cytokines, and growth factors under physiologic conditions. Like early‐response genes, these components are modulated by inhibitors of protein synthesis in some cell lines. To clarify the specific expression and regulation of mRNAs for urokinase (uPA), its receptor (uPAR), and type‐1 plasminogen activator inhibitor (PAI‐1), I analyzed RNA from four human cancer cell lines by RNA blotting after treatment with cycloheximide, anisomycin, emetine or puromycin. These inhibitors, all of which induced translational arrest, induced a very diverse response in the various transcripts, suggesting that the inhibitors mediate their effects through different molecular mechanisms. Dose‐response analysis showed that, in A549 cells, anisomycin strongly induced uPAR and PAI‐1 mRNA at concentrations that did not cause complete inhibition of protein synthesis, whereas cycloheximide induced these transcripts in a dose‐dependent manner only at concentrations sufficient to inhibit total protein synthesis by >90%. Puromycin induced the 3.4‐kb transcript of PAI‐1 mRNA in A549 and RD cells, whereas it decreased the expression of both the 3.4‐kb and 2.4‐kb PAI‐1 transcripts in HT‐1080 cells. Different time patterns of induction for uPA, uPAR and PAI‐1 mRNA suggest that even in the same cell type, inhibitors of protein synthesis mediate their effects on various genes through different mechanisms. Thus, induction of uPA, uPAR and PAI‐1 transcripts by inhibitors of protein synthesis was dependent on the gene, the cell line, and the type of inhibitor, and inhibition of protein synthesis per se was not sufficient for induction of these transcripts.
Starch synthesis‐, and tuber storage protein genes are differently expressed in Solanum tuberosum and in Solanum brevidens
Authors: Bánfalvi Zsófia , Molnár Attila , Molnár Gergely , Lakatos Lóránt , Szabó László
Published: April 2003

Studying in vitro stem cuttings of Solanum tuberosum induced for tuberization and those of a non‐tuberizing Solanum species, differences both in morphology and in gene expression were detected. Stolon formation essentially depended on light while tuberization was triggered by the elevated level of sucrose in the medium. Genes involved in starch synthesis were induced by sucrose in both species, however, starch granules were detected only in potato. A new tuber specific cDNA clone, GM7, encoding a putative metallocarboxypeptidase inhibitor and the cDNA of a proline rich cell wall protein with S. brevidens specific expression were isolated by differential screening. Sucrose mediated transcription of the tuber storage proteins like patatin and proteinase inhibitors (Kunitz‐type, winI, GM7) failed in S. brevidens.
Second messenger up‐regulation of androgen receptor gene transcription is absent in androgen insensitive human prostatic carcinoma cell lines, PC‐3 and DU‐145
Authors: Stubbs A.P. , Lalani E.-N. , Stamp G.W.H. , Hurst H. , Abel P. , Waxman J.
Published: April 2003

A theoretical pathway of transcriptional regulation of the androgen receptor (AR) gene is via a cAMP response element (CRE) present in its promoter region (−508 to −501). After 20 h of stimulation with 8‐bromo‐cAMP, AR mRNA was upregulated in LNCaP but not in either PC‐3 or DU‐145 cell lines. We have demonstrated that the level of CRE binding protein (CREB) was the same in all cell lines and that the putative AR‐CRE forms specific and competable protein interactions with CREB. The ability to regulate AR gene transcription via the second messenger pathway is lost in the PC‐3 and DU‐145 cell lines. This may be an important primary mechanism of androgen insensitivity in prostate cancer.
Rapid estimation of relative amide proton exchange rates of 15N‐labelled proteins by a straightforward water selective NOESY‐HSQC experiment
Authors: Böckmann Anja , Penin François , Guittet Eric
Published: April 2003

A straightforward heteronuclear pseudo‐3D NOESY‐HSQC pulse sequence using radiation damping to selectively invert magnetization at the water frequency was developed to estimate the amide proton exchange rates in 15N‐labelled proteins. The peak intensities in the resultant 2D spectrum allow a direct classification of amide proton exchange rates according to short (ms), intermediate (ms to s) or long (≥ s) residence times. This method was successfully used for the analysis of amide proton exchange rates in the 15N‐labelled FruR DNA‐binding domain and pertinent information about its dynamics was obtained.
Sequence specificity in CpG mutation hotspots
Authors: Ollila Juha , Lappalainen Ilkka , Vihinen Mauno
Published: April 2003

CpG dinucleotides are efficiently methylated in vertebrate genomes except in the CpG islands having a high C+G content. Methylated CpGs are the single most mutated dinucleotide. Sequences surrounding disease causing CpG mutation sites were analyzed from locus‐specific mutation databases. Both tetra‐ and heptanucleotide analyses indicated clear overall sequence preference for having pyrimidines 5′ and purines 3′ to the mutated 5‐methylcytosine. The most mutated tetranucleotides are TCGA and TCGG, the former being also a frequent restriction and modification site. The results will help in elucidating the still controversial mutation mechanism of CpG doublets.
Identification of the amino acid residues responsible for cold tolerance in Flaveria brownii pyruvate,orthophosphate dikinase
Authors: Ohta Shozo , Usami Satoru , Ueki Jun , Kumashiro Takashi , Komari Toshihiko , Burnell Jim N.
Published: April 2003

Pyruvate,orthophosphate dikinase (PPDK), an enzyme important in C4 photosynthesis, is typically a cold‐sensitive enzyme. However, a cold‐tolerant form of the enzyme has been isolated from the leaves of Flaveria brownii. Using an Escherichia coli expression system and the PPDK cDNAs from F. brownii (cold‐tolerant), F. bidentis (cold‐sensitive) and maize (intermediate cold tolerance), site‐directed mutagenesis studies indicated that as few as three amino acids residues (of 880 residues) strongly influence the cold sensitivity of Flaveria PPDK. Gel filtration analysis of the PPDK expressed in E. coli showed that subunit association and cold tolerance are closely linked.
Streptozotocin diabetes and the expression of GLUT1 at the brush border and basolateral membranes of intestinal enterocytes
Authors: Boyer S. , Sharp P.A. , Debnam E.S. , Baldwin S.A. , Srai S.K.S.
Published: April 2003

Changes in membrane expression of sodium‐dependent glucose transporter (SGLT1) and glucose transporter isoform (GLUT2) protein have been implicated in the increased intestinal glucose transport in streptozotocin‐diabetes. The possible involvement of GLUT1 in the transport response, however, has not previously been studied. Using confocal microscopy on tissue sections and Western blotting of purified brush border membrane (BBM) and basolateral membrane (BLM), we have examined enterocyte expression of GLUT1 in untreated and in 1 and 21 day streptozotocin diabetic rats. In control enterocytes, GLUT1 was absent at the BBM and detected at low levels at the BLM. Diabetes resulted in a 4‐ to 5‐fold increased expression of GLUT1 at the BLM and the protein could also be readily detected at the BBM. Insulin treatment of diabetic rats increased GLUT1 level at the BBM but was without effect on expression of the protein at the BLM.
Topology of the mitochondrial cAMP‐dependent protein kinase and its substrates
Authors: Sardanelli Anna Maria , Technikova-Dobrova Zuzana , Speranza Francesco , Mazzocca Antonio , Scacco Salvatore , Papa Sergio
Published: April 2003

In intact bovine heart mitochondria, cAMP‐dependent phosphorylation of 42, 29, 18 and 6.5 kDa proteins was inhibited by carboxyatractyloside. This shows that both mitochondrial cAMP‐dependent protein kinase (mtPKA) and its protein substrates are localized at the matrix side of the inner mitochondrial membrane. Proteins of 42, 29, 18, and 6.5 kDa were also bound at the outer surface of mitochondria where they were phosphorylated by the added purified catalytic subunit of PKA. In the cytosol from bovine heart proteins of the above molecular weights were phosphorylated by the cytosolic PKA.
A strategic framework for technical function management in manufacturing
Authors: Challis David , Samson Danny
Published: April 2003

Driven by the enhanced technological sophistication of products and production processes, the requirement to improve manufacturing plant return on investment and the need to better manage scarce technical resources, more firms are focusing on the activities of their technical functions. As many firms achieve or approach “best practice” in their organisational arrangements and management of human resources, there is an increasing recognition of the opportunities to enhance competitiveness through improved management of technology and technical functions. There is also substantial evidence to suggest that the development of new technology is occurring much faster than is the development of new approaches with which to manage it. This paper develops a framework, “technical effort”, through which to view technical activity in the context of improved business and organisational performance. This framework differs from traditional practice by integrating three different perspectives: maximising the contribution of technical functions to business outcomes, developing a sustainable source of competitive advantage in the form of an order winning set of technical capabilities and creating the working environment through which these requirements may be energised. It serves as a useful tool for Operations Managers to improve the strategic value of their technical functions by focusing learning on the linkages between business competitiveness, technical function outcomes, technical capabilities and organisational best practices.
Phosphoglycerides and their acyl group composition in myelin and microsomes of rat spinal cord during development
Authors: Sun Grace Y. , deSousa Byron N. , Danopoulos Vicki , Horrocks Lloyd A.
Published: April 2003

The phosphoglycerides and their acyl group composition in myelin and microsomes isolated from rat spinal cords were examined at various stages of the postnatal developmental period. In the immature cord, diacyl‐GPC is the major phosphoglyceride in both microsomal and myelin fractions. The proportion of this phosphoglyceride decreased steadily with age during development and the decrease was marked by an increase in diacyl‐GPE in microsomes and ethanolamine plasmalogen in both fractions. Marked changes in acyl group composition were observed in the microsomes during development of spinal cord, whereas acyl groups of myelin showed less extensive changes. A considerable amount of monoenoic fatty acid is already present in the myelin of 7‐day‐old cord. Acyl groups of diacyl‐GPC in the microsomal fraction indicated a decrease in 16:0, 16:1,20:4(n−6) and an increase in 18:0, 18:1 and 20:1 with respect to development. On the other hand, microsomal diacyl‐GPE and alkenylacyl‐GPE indicated a decrease in 16:0, 18:0 and 20:4(n−6), but an increase in 18:1 and 20:1. An exception is the proportion of 22:6(n−3) which increased in diacyl‐GPE and decreased in alkenylacyl‐GPE during development. The lack of obvious acyl group changes in myelin phosphoglycerides after 7 days of age is in agreement with the results of deSousa & Horrocks (Devl Neurosci. 1, 114–120, 1979) that myelination in spinal cord took on an early course and reached the adult composition sooner than the cerebrum.
Activity of muscle cultures measured by 2‐deoxyglucose uptake
Authors: Shainberg Asher , Pearl Rivka
Published: April 2003

Glucose consumption of skeletal muscle differentiated in vitro was studied under various experimental conditions by means of the [3H]deoxyglucose ([3H]DG) uptake technique. The results show that glucose uptake by skeletal muscle is a function of its activity; when the muscle is electrically stimulated to contract the uptake of [3H]DG is increased, and when spontaneous activity is inhibited, the uptake of [3H]DG is decreased. While electrical stimulation (ES) did not affect the uptake of 3‐O‐methyl‐glucose (3‐OMG), DG uptake was enhanced in spite of the presence of cycloheximide in electrically stimulated cultures, suggesting that muscle contraction probably activates the enzyme hexokinase. Thus our data show that the uptake of [3H]DG can be a tool for measuring muscle contraction.
Long‐chain acyl coenzyme A synthetase activity during the postnatal development of the mouse brain
Authors: Reddy T. Sanjeeva , Bazan Nicolas G.
Published: April 2003

Palmitic, linoleic, arachidonic, and docosahexaenoic acids were used as substrates to study fatty acid activation in the mouse brain and liver during postnatal development. Long‐chain acyl coenzyme A synthetase showed peak activity during the period of rapid oligodendroglial proliferation and myelination. In brain, activation of linoleic and arachidonic acids was highest, followed by palmitic and docosahexaenoic acids. In liver, no appreciable change in enzyme activity was seen during the period of development studied. Palmitic and arachidonic acids showed the highest rate of activation, followed by docosahexaenoic acid. These ontogenic data suggest the presence of a single long‐chain acyl coenzyme A synthetase in brain.
A pharmacologic investigation of the ‘transport response’ in the white rat
Authors: Wilson Christopher , Cullen Ellen , Sendell Kelly
Published: April 2003

In a series of six experiments, the ability of specific neurotransmitter antagonists to alter the ‘transport response’ was investigated in 19‐day‐old rat pups. The serotonergic blocker, methysergide, and the cholinergic blocker, scopolamine, did not produce any consistent changes in the intensity of the response. Likewise, the opiate receptor blocker, naloxone, was without effect. Large, dose‐dependent decreases in transport response intensity were seen with administration of the beta‐noradrenergic receptor blocker, propranolol, and with administration of the dopaminergic blocker, haloperidol. The alphanoradrenergic receptor blocker, phentolamine, produced inconsistent changes in the response. These results indicate a central catecholaminergic involvement in the transport response.
A morphometric study of mouse trigeminal roots after unilateral destruction of vibrissae follicles at birth
Authors: Savy C. , Margules S. , Solari A. , Wehrle R. , Verley R. , Farkas‐Bargeton E.
Published: April 2003

Trigeminal sensory roots were studied in neonatal mice. On the deafferented side, the surface area of the cross‐section through the sensory root is diminished by 31% and the number of myelinated fibers is reduced by 21%. but the proportion between myelinated and unmyelinated fibers remains unchanged. The distribution of axonal diameters, analysed in 7 dorso‐ventral scanning bands through the sensory roots, indicates a loss or eventually an atrophy of large myelinated axons in the medial two thirds of the sensory root. In both control and deafferented sides the diameter of the myelinated fiber (outside the myelin sheath) is proportional to the axon diameter (inside the myelin sheath). Our results confirm the loss of most of the neurons innervating vihrissae and the lack of regeneration or sprouting in the deafferented root in the newborn mouse.
Effect of activity on the selective stabilization of the motor innervation of fast muscle posterior latissimus dorsi from chick embryo
Authors: Bourgeois Jean‐Pierre , Toutant Madeleine , Gouzé Jean‐Luc , Chanceux Jean‐Pierre
Published: April 2003

The role of neuromuscular activity in the maturation of the motor innervation was investigated in the fast focally innervated posterior latissimus dorsi (PLD) muscle of the chick embryo. The axonal supply in the PLD motor nerve, and the focal multiple innervation of the endplates were described on days 15 and 16 of embryonic life in normal and experimental embryos. In the first series of experiments, chick embryos were paralyzed by repeated injections between days 4 and 10 in ovo of the curare‐like agent, flaxedil. Twice more axons in the PLD motor nerve and about twice more nerve terminal profiles at the endplates in the PLD muscles were found in paralyzed than in control embryos.

In a second series of experiments, electrodes were implanted around the spinal cord of 7‐day‐old embryos and electric pulses delivered at 0.5 Hz frequency from day 10 to days 15–16 of incubation. At day 15.5, no change was observed in the axonal supply in the PLD motor nerve of stimulated embryos, while a two‐fold decrease was observed in the number of motor nerve terminal profiles per endplate in the corresponding PLD muscle.

The statistical distribution of the number of motor nerve terminal profiles per endplate was described from complete semi‐serial sections in the PLD muscle from normal, paralyzed and stimulated chick embryos. In these three cases, the distribution of supernumerary nerve terminal profiles followed a Poisson law after one nerve ending had been subtracted from the number of nerve endings counted per endplate.
Experimental maternal hyperpipecolatemia decreases DNA in the mouse brain
Authors: Kim Jang Soo , Gutierrez Maria d.C. , Giacobini Ezio , Sundberg John P.
Published: April 2003

Pipecolic acid represents the major metabolite of lysine in the CNS. This study aimed to mimic the known pathological condition of hyperpipecolatemia in human neonates by maintaining high and steady concentrations in the mouse brain both pre‐ and postnatally. Although histological observations did not reveal any abnormal findings in the brain, liver and kidney, the offsprings of mothers which were injected during pregnancy with 250 mg/kg PA presented a significant decrease in both cortical and whole brain DNA content. Protein, RNA and CNPase activity were not altered. The changes in DNA content are of particular interest since they demonstrate that a high and steady level of pipecolic acid, which is comparable to the level seen in human hyperpipecolatemic brain, can induce a neurotoxic effect in the fetal mouse brain. Mice injected with the same dose from day 1 to day 29 after birth did not show any change in DNA content in the cortex. These results suggest that the critical period from pipecolic acid neurotoxic effect is prenatal, probably due to a selective vulnerability of developing neurons to high levels of pipecolic acid.

The decrease in DNA concentration induced by maternal hyperpipecolatemia suggests a neurotoxic effect of pipecolic acid on cell proliferation during fetal development which could be related to the neuronal damage observed in the brain of hyperpipecolatemic neonates.
Development of taurine biosynthesizing system in cerebral cortical neurons in primary culture
Authors: Ohkuma S. , Tomono S. , Tanaka Y. , Kuriyama K. , Mukainaka T.
Published: April 2003

Developmental patterns of taurine biosynthesizing system were investigated using primary cultured neurons prepared from the neopallium of 15‐day‐old fetal mice by a trypsin treatment in comparison with those in cerebral cortices obtained from age‐matched fetal and neonatal mice. The morphological observations by phase contrast and scanning electron micrographies indicated that the cells in primary culture used in the present study possessed typical features of neurons. In addition, the immunohistochemical studies using the antibody to glial fibrillary acidic protein (GFAP), a specific marker for astroglia, revealed that the contamination of astroglias was negligible. The contents of taurine and metabolic intermediates in taurine biosynthesis, cysteine sulfinic acid and cysteic acid, in primary cultured neurons showed decreases during their development, especially during the first week after the inoculation. Similar developmental patterns of these amino acids were observed in cerebral cortices in vivo during perinatal stage which corresponded to the first week of neuronal growth in vitro. On the other hand, the activities of cysteine sulfinic acid decarboxylase and cysteine dioxygenase, both of which are involved in the biosynthesis of taurine, were found to be increased progressively both in primary cultured neurons and in cerebral cortices in vivo during their growth. The immunohistochemical study using antitaurine antibody obtained from rabbit clearly demonstrated that immunoreactive materials were localized in cell bodies and the processes of neurons, and the intensity of the immunoreactivity in primary cultured neurons also showed a reduction with time of culture. These results indicate that primary cultured neurons used in this study possess a similar capacity to synthesize taurine from cysteine as developing brains in vivo. The present results also strongly suggest the well known decrease in cerebral taurine content in vivo during neonatal stages may be predominantly due to the decrease of taurine in neuronal cells.
Effects of light‐ and dark‐rearing on the postnatal development of GABA receptor sites in the chick optic lobe
Authors: Ríos Hugo , Flores Vladimir , de Plazas Sara Fiszer
Published: April 2003

To investigate the ability of GABA receptor sites to undergo environmental‐dependent plastic changes, the postnatal developmental pattern of GABA receptors was studied under different levels of light stimulation, i.e. normal‐, light‐ and dark‐rearing. At hatching the specific binding of (3H)GABA was 1.74 ± 0.36 pmol/optic lobe. In normally reared chicks the number of GABA binding sites showed a transient increase with the highest value at the 6th day (7.0 ± 1.32 pmol/optic lobe). This value is higher than the one reached at the adult stage. Between the 3rd and 6th day, there was a 33.7% increase in specific [3H]GABA binding in light‐reared compared with normally reared animals (P < 0.05). In the dark‐reared chicks, the specific binding was 36.4% lower than that found in normally reared (P < 0.02). However, the changes in receptor density were transient since at the 17th day the number of GABA binding sites returned to adult levels. Scatchard analysis revealed that the differences observed in the high affinity GABA binding sites between the three groups were due to modifications in the total number of binding sites while the affinity remained unchanged. The maximal number of binding sites were: 2.71, 7.01 and 1.79 pmol/mg protein in normally, light‐ and dark‐reared chicks, respectively; while the apparent dissociation constants were unaffected: 3.2, 3.4 and 3.6 nM, respectively. These results show that, during postnatal development, different conditions of visual experience produce synaptic changes at the molecular level. These changes probably occur within a period of high plasticity, prior to the end of a critical period.
Morphometric analysis of the cerebellar Purkinje cell in the developing normal and hypothyroid chick
Authors: Bouvet J. , Usson Y. , Legrand J.
Published: April 2003

A morphometric analysis of Purkinje cells in the developing cerebellar cortex of the chick was performed in normal animals and embryos made hypothyroid by one or two spaced injections of tetramethylthiourea. Profiles of 162 Purkinje cells, from Golgi‐Cox treated sections were analysed. Soma area, perimeter and circularity index, cumulative length of the dendrites and number of dendritic bifurcations were studied. The results showed significant differences between control and hypothyroid animals. There were no important differences between birds rendered transiently hypothyroid with a single injection and those made chronically hypothyroid with dual injections. This confirms that the Purkinje cell is very dependent on thyroid hormone especially during the early phases of its morphogenesis. The development of the Purkinje cell was the most affected process of cerebellar cortex maturation in the thyroid‐deficient chick. The dendritic arborization was particularly hypoplastic. Moreover, a dynamic balance appeared to exist between the development of the dendritic arborization and that of the perikaryon.
l‐Aspartate and l‐glutamate binding sites in developing normal and ‘nervous’ mutant mouse cerebellum
Authors: Angelatou F. , Mitsacos A. , Goulas V. , Kouvelas E. D.
Published: April 2003

This study concerns the ontogeny and the cellular localization of l‐aspartate and l‐glutamate binding sites in normal and ‘nervous’ mutant mouse cerebellar membranes. The binding kinetics revealed for l‐aspartate a single binding system (Kd = 750 nM) and for l‐glutamate also a single binding component of higher affinity (Kd = 344 nM). The pharmacological study, using various amino acid analogues, revealed a differential specificity for the binding sites of the two amino acids.

The developmental study showed that the binding sites of both amino acids appear mainly during the second and third week of life, a period when parallel and climbing fiber synaptogenesis occurs, but they follow a slightly different developmental pattern. The study using ‘nervous’, mutant mouse cerebellum showed an age‐dependent decrease of l‐aspartate and l‐glutamate binding, which coincides in time with the Purkinje cell degeneration in this mutant, indicating a cellular localization of these binding sites on the Purkinje cell membranes. These results suggest that l‐aspartate and l‐glutamate binding sites may be respectively associated with the postsynaptic target of climbing and parallel fibers on the Purkinje cell dendrites. However, the decrease of specific binding in ‘nervous’ mutant mouse cerebellum was about 50% for l‐aspartate and 60% for l‐glutamate, implying that a significant number of l‐aspartate and l‐glutamate binding sites are located on cerebellar elements other than the Purkinje cell membranes.
Induction of cytoskeletal alterations in C6 glioma by glia maturation factor
Authors: Ryken Timothy C. , Turner J. Wesley , Hicklin Danny J. , Miller Joyce F. , Baggenstoss Bruce A. , Lim Ramon
Published: April 2003

C6 rat glioma cells respond to glia maturation factor (GMF) with characteristic morphological alterations. Observed under phase‐contrast microscopy, the cells changed from a rounded morphology in random formation to a spindle‐shaped appearance in parallel arrays. Observed under scanning electron microscopy, GMF led to a decrease in the number of microvilli and cell surface knobs. Transmission electron microscopy demonstrated the appearance of numerous microtubules aligned with the long axis of the cells after GMF stimulation. The change in cell shape and histotypic pattern was inhibited by vinblastin, further implicating the involvement of microtubules. Immunofluorescence using anti‐α‐tubulin revealed a well‐defined cytoskeletal system in GMF‐stimulated cells but not in the control cells. Finally, an increase in tubulin was confirmed with enzyme‐linked immunosorbent assay (ELISA) on extracts from these cultures. The findings indicate that morphological alterations induced by GMF are associated with changes in the quantity and arrangement of microtubules.
Influences of pertussis toxin, guanine nucleotides and forskolin on adenylate cyclase in striatal membranes of infant, adult and senescent rats
Authors: Nomura Yasuyuki , Arima Takashi , Swgawa Tomio
Published: April 2003

To identify age‐related changes in the dopamine (DA) receptors‐GTP‐binding protein‐adenylate cyclase system, the following experiments were performed at 7 days (infant), 70 days (adult) and 2 years (senescent) in striatal membranes of rats: (1) effects of GTP in the presence and absence of pertussis toxin (islet‐activating protein, IAP) on adenylate cyclase in the presence of forskolin alone, (2) the same in the presence of forskolin plus DA and (3) the corresponding effect of guanyl‐5′‐yl‐β, α‐imido‐diphosphate (GppNHp). GTP caused biphasic effects: the activation at 1 μM and the inhibition at 100 μM on forskolin‐stimulated cyclase activity at 70 days. The inhibition was suppressed with IAP pretreatment. In infant membranes, 100 μM GTP inhibited the activity in the absence and presence of 100 μM DA and IAP induced a reversal from the inhibition to the stimulation only in the presence of DA. In senescent animals, neither GTP nor IAP affected the activity. GppNHp at 1, 10 and 100 μM only activated and did not inhibit forskolin‐stimulated cyclase at each stage. GppNHp‐caused stimulation was no more affected by IAP. IAP ADP‐ribosylated 41,000 dalton proteins at each stage and the specific activity of ADP‐ribosylation was not changed during development and aging. It is suggested that inhibitory GTP‐binding protein (Gi) with molecular size of 41,0000 dalton is involved in DA receptor‐adenylate cyclase system whose function is low at infant stage and markedly decreased at senescent stage in rat striatal membranes.
Do catecholamines contribute to the effects of neonatal hypoxia on development of brain and heart? Influence of concurrent α‐adrenergic blockade on ornithine decarboxylase activity
Authors: Slotkin Theodore A. , Orband‐Miller Lisa , Queen Kennedy L.
Published: April 2003

Hypoxia in the neonate releases catecholamines from the adrenal medulla, a response which is necessary to survive. This study examines whether a similar dependence exists for the ability of brain and heart tissue to recover from hypoxia‐induced damage, as assessed by measurements of ornithine decarboxylase (ODC) activity. Hypoxia at either 1 day or 8 days of age produced a subsequent elevation of brain ODC which persisted for 1 week, a pattern known to be associated with recovery from tissue damage and delayed cellular maturation. Pretreatment of the rats with phenoxybenzamine, an α‐receptor blocking agent, resulted in attenuation of the long‐term ODC response, but did not interfere with effects on the enzyme during the hypoxia itself. In the heart, hypoxia at 8 days of age displayed similar effects, with long‐term ODC elevations which were attenuated by phenoxybenzamine. Hypoxia at 1 day of age also produced long‐term heart ODC stimulation, but in this case the effect was exacerbated by phenoxybenzamine, an effect consistent with the greater dependence of cardiac tissue on α‐receptor‐mediated responses to hypoxia at that age. These results suggest that α‐receptor stimulation by catecholamines released during neonatal hypoxia play a role in the metabolic adjustment of brain and heart tissue to damage and may aid in subsequent recovery.
Immunohistochemical localization of l‐Ornithine decarboxylase in developing rat brain
Authors: Dorn A. , Müller M. , Bernstein H.‐G. , Pajunen A. , Järvinen M.
Published: April 2003

l‐Ornithine decarboxylase, the rate limiting enzyme of polyamine biosynthesis and a marker enzyme of tissue proliferation and maturation, was localized immunocytochemically in the developing rat central nervous system. It can be noted that the distribution of the enzyme protein underlies temporal alterations. Conclusions are drawn from the location of the enzyme and possible functional roles played by ornithine decarboxylase in discrete brain areas.
Proliferation of rat astrocytes, but not of oligodendrocytes, is stimulated in vitro by protease inhibitors
Authors: Perraud F. , Besnard F. , Labourdette G. , Sensenbrenner M.
Published: April 2003

Various natural protease inhibitors stimulate the proliferation of rat astrocytes grown in primary culture in the absence of serum. They are inactive on the proliferation of oligodendrocytes. The mean level of stimulation of the astrocyte proliferation elicited by the protease inhibitors is higher when the cells are in the growth phase, at low cell density than when they are quiescent, at high cell density. Among the protease inhibitors tested three serum proteins, α1‐antitrypsin, α2‐macroglobulin and antithrombin III were the most active. The present results, taken together with our previous finding that thrombin and some other proteases also stimulate the proliferation of astroglial cells but not of oligoden‐droglial cells, suggest that proteases and protease inhibitors participate, through still unclear mechanisms, in the control of the proliferation of astrocytes, but not in that of oligodendrocytes, during brain ontogenesis.
Responses of cholinergic markers to a pre‐ or a postsynaptic pharmacological blockage in the developing chick embryo spinal cord
Authors: Thiriet G. , Kempf E. , Ebel A.
Published: April 2003

The response of cholinergic markers to pre‐ or postsynaptic blockage was followed during development of the chick embryo spinal cord, to understand better the maturation sequence of the developing cholinergic synapse. It has been shown that the developing neurotransmitter system is able to react to pre‐ or postsynaptic disturbances by compensatory mechanisms, as early as 7.5 days of incubation. From 12.5 days of incubation the synaptic reactivity to such blockage changes in complexity as well as in nature. At this developmental stage muscarinic receptors show capacity for intrinsic regulation, similar to that of the adult nervous system. These results together with our previous studies clearly demonstrate that 12.5–15.5 days of embryonic life appears to be a crucial period in ontogenesis of the cholinergic neurotransmission in the chick embryo spinal cord.