bluuebunny/crossref_metadata_2025 huggingface dataset:
Intraorganellar localization of CoASH‐independent phytanic acid oxidation in human liver peroxisomes
Authors: Pahan Kalipada , Singh Inderjit
Published: July 2002

In human tissues phytanic acid is α‐oxidized to pristanic acid in peroxisomes. Studies of the intraorganellar site of α‐oxidation of [1‐14C]phytanic acid to pristanic acid in peroxisomes isolated from human liver demonstrate that phytanoyl‐CoA ligase is present in the peroxisomal membrane and that the enzyme system for α‐oxidation of phytanic acid to pristanic acid is in the peroxisomal matrix. In contrast to the β‐oxidation system for fatty acids, the substrate for α‐oxidation is free phytanic acid. The studies described in this manuscript report a novel fatty acid oxidation system where the substrate for the enzyme system is free fatty acid; however, phytanoyl‐CoA ligase regulates the α‐oxidation of phytanic acid at the organellar (peroxisomal) level.
cDNA cloning of a new type of subunit of mammalian proteasomes
Authors: Thomson Stuart , Balson Deborah F. , Rivett A.Jennifer
Published: July 2002

The primary structure of a new type of subunit (RN3) of rat proteasomes (multicatalytic proteinase complexes) has been determined from the nucleotide sequence of the cDNA. The cDNA encodes a protein of 232 amino acids but the directly determined N‐terminal amino acid sequence suggests that the subunit is post‐translationally processed to a M
r = 24k form. Sequence alignments reveal a similarity of RN3 to other proteasome subunits. It can be designated a B‐type proteasomal subunit but is not closely related to the β subunit of the archaebacterial proteinase or to other members of the B group.
Changes in cell cycle‐associated gene expression in a model of impaired liver regeneration
Authors: Albrecht Jeffrey H. , Hoffman Jeffrey S. , Kren Betsy T. , Steer Clifford J.
Published: July 2002

Following partial hepatectomy (PH) there is compensatory regeneration of the remnant liver which eventually restores hepatic mass and function. The response to PH was studied in normal BALB/c and athymic nude mice, a model of impaired liver regeneration. Following PH, nude mice demonstrated diminished peak hepatic [3H]thymidine uptake and delayed liver mass restoration through 60 h post‐PH. However, between 72–120 h there was no significant difference in mass restoration between the groups. The expression of genes associated with different stages of the cell cycle was evaluated in both models. In nude mice, there was an increase in peak expression of c‐jun transcripts, while c‐myc transcript expression was moderately attenuated. Thymidine kinase (TK) and cyclin‐dependent kinase 1 (CDK1) mRNA expression was also diminished in athymic nude mice. The results suggest that while the defect in the regenerative response of the nude mouse after PH affects events in several phases of the cell cycle, mass restoration of the liver is only delayed and not attenuated.
Solubilization and purification of aldehyde‐generating fatty acyl‐CoA reductase from green alga Botryococcus braunii
Authors: Wang Xing , Kolattukudy Pappachan E.
Published: July 2002

Membrane‐bound fatty acyl‐CoA reductase from the green alga Botryococcus braunii has been solubilized from the microsomal preparation by 0.1% octyl β‐glucoside and purified to near homogeneity by Blue A agarose and palmitoyl‐CoA agarose affinity column chromatography. The molecular mass of the enzyme was estimated by SDS‐PAGE to be 35 kDa. The enzyme generates fatty aldehyde by reduction of fatty acyl‐CoA with NADH as the reductant. The N‐terminal amino acid sequence of this protein that represents the first eucaryotic aldehyde‐generating reductase to be purified shows high homology with the N‐terminus of fatty acid reductase from bacteria.
A novel yeast protein showing specific association with the cyclin‐dependent kinase 5
Authors: Huang Q.-Q. , Lee K.-Y. , Wang J.H.
Published: July 2002

The present study describes a significant amino acid sequence homology between neuronal Cdk5 activator (nck5a) and an open reading frame of an unknown gene on the yeast S. cerevisiae chromosome III. A cDNA encoding a 25 kDa fragment of this yeast protein, the region containing homologous sequence to nck5a was cloned and expresed in E. coli as a glutathine‐S‐transferase fusion protein (GST p25Y). GST‐p25Y was found to block the in vitro activation of Cdk5 by nck5a and to affinity precipitate Cdk5 from bovine brain extract. The observations indicate that the yeast protein is capable of specific and high affinity association with Cdk5.
The C1q binding activity of IgG is modified in vitro by reactive oxygen species: implications for rheumatoid arthritis
Authors: Griffiths H.R. , Lunec J.
Published: July 2002

IgG can be denatured in vitro by reactive oxygen species (ROS). Native IgG activates the complement cascade through C1q. Using a modified ELISA, C1q binding activity of rheumatoid IgG has been compared to IgG denatured by neutrophil‐derived ROS. The C1q binding activity of rheumatoid synovial fluid IgG is greater than the corresponding serum IgG (P < 0.01). Denaturation of IgG by activated polymorphs or the Fenton reaction decreased its C1q binding activity (P < 0.01). In vitro exposure of IgG to OH· and ROO· increased its interaction with C1q (P < 0.01). Hypochlorous acid had no effect. ROS‐induced alteration to IgG‐C1q binding activity may promote the inflammatory response in rheumatoid arthritis.
Binding of contactin/F11 to the fibronectin type III domains 5 and 6 of tenascin is inhibited by heparin
Authors: Weber Peter , Ferber Philippe , Fischer René , Winterhalter Kaspar H. , Vaughan Lloyd
Published: July 2002

The structural basis for the interaction between tenascin‐C and the neuronal cell adhesion molecule, contactin/F11, was investigated using plasmon surface resonance technology. The binding site on tenascin‐C for contactin/F11 is shown to span the two fibronectin type III homology domains 5 and 6. Either domain alone is insufficient for binding. Heparin, heparan sulfate and dermatan sulfate inhibit this interaction through binding to a conserved heparin‐binding site on domain 5. In contrast, chondroitin sulfates A and C have no such effect.
Genomic Exploration of the Hemiascomycetous Yeasts: 8. Zygosaccharomyces rouxii1
Authors: de Montigny Jacky , Straub Marie-Laure , Potier Serge , Tekaia Fredj , Dujon Bernard , Wincker Patrick , Artiguenave François , Souciet Jean-Luc
Published: July 2002

This paper reports the genomic analysis of strain CBS732 of Zygosaccharomyces rouxii, a homothallic diploid yeast. We explored the sequences of 4934 random sequencing tags of about 1 kb in size and compared them to the Saccharomyces cerevisiae gene products. Approximately 2250 nuclear genes, 57 tRNAs, the rDNA locus, the endogenous pSR1 plasmid and 15 mitochondrial genes were identified. According to 18S and 25S rRNA cladograms and to synteny analysis, Z. rouxii could be placed among the S. cerevisiae sensu lato yeasts.
Chromaffin granule membranes contain at least three heme centers: direct evidence from EPR and absorption spectroscopy
Authors: Kamensky Yury A. , Palmer Graham
Published: July 2002

Low‐temperature electron paramagnetic resonance (EPR) spectroscopy, circular dichroism and two‐component redox titration have previously provided evidence for two different ascorbate‐reducible heme centers in cytochrome b
561 present in chromaffin granule membranes. These species have now been observed by room and liquid nitrogen temperature absorption spectroscopy. The visualization of these heme centers becomes possible as a consequence of utilizing chromaffin granule membranes prepared by a mild procedure. Additionally, a new redox center, not reducible by ascorbate, was discovered by both EPR and absorption spectroscopy. It constitutes about 15% of the heme absorbance of chromaffin membranes at 561 nm and has EPR characteristics of a well‐organized highly axial low‐spin heme center (thus making it unlikely that it is a denatured species). This species is either an alternative form of one of the hemes of cytochrome b
561 that has a very low redox potential or a b‐type cytochrome distinct from b
561.
Superoxide dismutases enhance H2O2‐induced DNA damage and alter its site specificity
Authors: Midorikawa Kaoru , Kawanishi Shosuke
Published: July 2002

Superoxide dismutases (SODs) are involved in the protection of cells from oxygen toxicity. However, several papers have reported that the overexpression of CuZn‐SOD causes oxidative damage to cells. We investigated a mechanism by which an excess of SODs accelerates oxidative stress. The presence of CuZn‐SOD, Mn‐SOD or Mn(II) enhanced the frequency of DNA damage induced by hydrogen peroxide (H2O2) and Cu(II), and altered the site specificity of the latter: H2O2induced Cu(II)‐dependent DNA damage with high frequency at the 5′‐guanine of poly G sequences; when SODs were added, the frequency of cleavages at thymine and cytosine residues increased. SODs also enhanced the formation of 8‐oxo‐7,8‐dihydro‐2′‐deoxyguanosine by H2O2and Cu(II). We conclude that SODs may increase carcinogenic risks, e.g. of tumors in Down syndrome.
Acetylcholine receptor subunit homomer formation requires compatibility between amino acid residues of the M 1 and M2 transmembrane segments
Authors: Vicente-Agulló Francisco , Rovira JoséC. , Campos-Caroa Antonio , Rodríguez-Ferrer Carmen , Ballesta Juan J. , Sala Salvador , Sala Francisco , Criado Manuel
Published: July 2002

The neuronal nicotinic acetylcholine receptor (nAChR) subunits a3 and 0 have different assembly behavior when expressed in heterologous expression systems: α3 subunits require other subunits to assemble functional nAChRs, whereas α7 subunits can produce homomeric nAChRs. A previous analysis of chimeric constructs identified a domain comprising the first putative membrane‐spanning segment, M1, as essential to homomeric assembly. The present study dissected further this domain, identifying three amino acid residues, which are located at the most intracellular third of the M1 transmembrane segment, as important in the assembly of homomers. Moreover, formation of homooligomeric complexes seems to require a compatible accommodation between this region and certain residues of the second transmembrane segment, M2. Thus, compatibility between defined domains of the M1 and M2 transmembrane segments appears as a determinant factor governing homomer association of nAChR subunits.
COOH‐terminal decamers in proteins are non‐random
Authors: Berezovsky Igor N , Kilosanidze Gelena T , Tumanyan Vladimir G , Kisselev Lev
Published: July 2002

© 1997 Federation of European Biochemical Societies.
Inherited retinal degeneration: basic FGF induces phagocytic competence in cultured RPE cells from RCS rats
Authors: McLaren M.J , Inana G
Published: July 2002

In RCS rats, the retinal pigment epithelium (RPE) is defective in phagocytosis of photoreceptor membranes. We have previously shown reduced expression of basic fibroblast growth factor (bFGF) in the RPE of 7–10‐day‐old RCS rats. This study using primary RPE cultures from rats of this age demonstrates that the phagocytic defect in the mutant RPE can be overcome by treatment with bFGF, by a mechanism involving gene transcription and that normal RPE phagocytosis, also requiring transcription, is blocked by a bFGF neutralizing antibody. The combined data point to a role for bFGF in the normal mechanism of RPE phagocytosis and the RCS defect.
The MBP fusion protein restores the activity of the first phosphatase domain of CD45
Authors: Lorenzo Hans K , Farber Donna , Germain Valérie , Acuto Oreste , Alzari Pedro M
Published: July 2002

CD45 is a receptor‐like protein tyrosine phosphatase critically involved in the regulation of initial effector functions in B‐ and T‐cells. The protein comprises two phosphatase (PTP) domains in its cytoplasmic region. However, whether each PTP domain has enzyme activity by itself or whether both domains are required to build up a functional enzyme is unclear. We have studied different constructions of human CD45 comprising the two PTP domains, both separately and as a single protein, fused to maltose‐binding protein (MBP). In apparent contrast with previous studies, we show that the first PTP domain of CD45 (when fused to MBP) may be a viable phosphatase in the absence of the second domain. Phosphatase activity resides in the monomeric form of the protein and is lost after proteolytic cleavage of the fusion partner, indicating that MBP specifically activates the first PTP domain. Furthermore, changes in the optimal pH for activity with respect to wild‐type CD45 suggest that protein–protein interactions involving residues in the neighbourhood of the catalytic site mediate enzyme activation.
The activation‐dependent induction of APN‐(CD13) in T‐cells is controlled at different levels of gene expression
Authors: Wex Th , Bühling F , Arndt M , Frank K , Ansorge S , Lendeckel U
Published: July 2002

Recently, it was shown that aminopeptidase N (E.C. 3.4.11.2, CD13) is up‐regulated during mitogenic stimulation of peripheral T‐cells. In this study, we demonstrate that the half‐life of APN mRNA was considerably prolonged in these cells leading to a 2.7‐fold increase of APN transcript level. The apparent half‐life time of the APN transcript was investigated by the RNA synthesis inhibitor‐chase method using actinomycin D. The steady‐state APN mRNA levels was determined by a competitive RT‐PCR. The half‐lives estimated in resting T‐cells, natural killer cells and permanently growing tumour cells varied between 3.5 and 6 h. Finally, nuclear run‐on assays revealed that the APN gene expression of stimulated T‐cells is controlled by increased promoter activity as well. These studies suggest a control of APN gene expression at the post‐transcriptional level in addition to promoter‐mediated regulation.
Heme C incorporation into the c‐type cytochromes FixO and FixP is essential for assembly of the Bradyrhizobium japonicum cbb3‐type oxidase
Authors: Zufferey Rachel , Hennecke Hauke , Thöny-Meyer Linda
Published: July 2002

The monoheme and diheme c‐type cytochromes FixO and FixP are two of the subunits of the respiratory cbb
3‐type oxidase of Bradyrhizobium japonicum. The cysteines of the respective heme C binding motifs CXXCH were changed to serines by site‐directed mutagenesis, which led to inactive oxidases in all mutants. Western blot analyses showed that an intact heme binding site in the FixO polypeptide is a prerequisite not only for the synthesis of holo‐FixO protein but also for the formation of the entire cbb
3‐type oxidase complex. Both heme binding sites of FixP were essential for maturation and assembly of this subunit. It was not possible to create stable FixP variants that contained only one heme C.
The mouse filensin gene: structure and evolutionary relation to other intermediate filament genes
Authors: Gounari Fotini , Karagianni Niki , Mincheva Antoaneta , Lichter Peter , Georgatos Spyros D , Schirrmacher Volker
Published: July 2002

Filensin and phakinin are two lens‐specific members of the intermediate filament (IF) superfamily of proteins. They coassemble to form a beaded submembraneous filamentous network, the beaded filaments (BFs). The low sequence homology and differences in assembly compared to other IF proteins do not allow their classification in any of the five IF subgroups. The organization of the phakinin gene exon/intron boundaries provides evidence that this partner may be sharing a common origin with type I cytokeratin genes. Here we report the molecular cloning, sequence and characterization of the mouse filensin gene. The filensin gene consists of 8 exons and 7 introns, with 6 introns interrupting its rod domain in a highly conserved manner characteristic of type III IF genes, like vimentin, desmin, or peripherin. Of the two tail domain exons the one adjacent to the rod domain, compares to exon 7 of the non‐neuronal cytoplasmic IF gene of helix aspersa and to the lamin region bridging the end of the rod domain to the nuclear localization signal. Altogether, these observations indicate that the lens beaded filaments form an independent class of IF.
Evidence for a posttranscriptional effect of retinoic acid on connexin43 gene expression via the 3′‐untranslated region
Authors: Clairmont Annette , Sies Helmut
Published: July 2002

All‐trans retinoic acid (10−7 M) induces cell–cell communication and the expression of the gap junction protein connexin43 in mouse F9 teratocarcinoma cells. Previous experiments revealed an increase of mRNA but no change in the transcription of connexin43, suggesting a posttranscriptional mechanism responsible for the regulation of connexin43 gene expression. In transient transfection experiments using an expression vector containing the 3′‐untranslated region of the connexin43 gene downstream of the luciferase coding sequence driven by the connexin43 promoter we show here that retinoic acid enhances luciferase activity via the connexin43 3′‐untranslated region due to altered stability of the mRNA. Thus, retinoic acid is able to influence connexin43 gene expression at the level of mRNA stability via elements located in the 3′‐untranslated region.
Molecular cloning and functional characterization of the cDNA encoding the murine thiopurine S‐methyltransferase (TPMT)
Authors: Fessing Michael Y , Belkov Vladimir M , Krynetski Eugene Y , Evans William E
Published: July 2002

Thiopurine S‐methyltransferase (TPMT) is a cytosolic enzyme that catalyzes S‐methylation of aromatic and heterocyclic sulfhydryl compounds, including anticancer and immunosuppressive thiopurines. Here we report the isolation and functional characterization of the murine TPMT cDNA. The screening of expressed sequence tags database led to isolation of a murine cDNA clone containing an uninterrupted ORF encoding the protein with an amino acid sequence that is 82% similar and 78% identical to the human TPMT. The expression product of the murine cDNA in rabbit reticulocyte and wheat germ lysate coupled transcription‐translation systems showed TPMT enzymatic activity. We conclude that the isolated cDNA clone represents the murine TPMT cDNA.
Contribution of arginine‐82 and arginine‐86 to catalysis of RNases from Bacillusintermedius (binase)
Authors: Yakovlev Gennady I , Struminskaya Nina K , Znamenskaya Lilia V , Kipenskaya Larisa V , Leschinskaya Inna B , Hartley Robert W
Published: July 2002

To elucidate the functional role of Arg82 and Arg86 in the enzyme activity of binase, the extracellular ribonuclease of Bacillus intermedius, we used site‐directed mutagenesis. On cleavage of various substrates the catalytic activity of binase mutant Arg86Ala is 2.7×103–7.7×103 times less than that of the native enzyme. The decrease in activity is determined preferentially by the decrease in the molecular rate constant k
cat with a relatively small change of enzyme‐substrate affinity, characterized by K
m. This is the expected result if Arg86 acts to lower the energy of a transition state of the reaction. The replacement of Arg82 by Ala causes a 5–19‐fold activity decrease, depending on the substrate. We propose that this residue does not have a direct catalytic function in the molecular mechanism of the binase action and that the activity decrease of binase on the replacement of Arg82 by alanine is mediated by the effect of Arg82 on the pK of catalytic residues.
Cloning, expression and characterisation of a new human low Mr phosphotyrosine protein phosphatase originating by alternative splicing
Authors: Modesti A , Marzocchini R , Raugei G , Chiti F , Sereni A , Magherini F , Ramponi G
Published: July 2002

RT‐PCR experiments on RNA from K562 and HepG2 cells and from human placenta led to the isolation of a novel cDNA, a further alternative splicing product of the primary transcript of low M
r phosphotyrosine phosphatase (LMW‐PTP), already known to produce isoforms 1 and 2. This new transcript represents 15–20% of the total LMW‐PTP mRNA in the cell. This novel cDNA codifies for a protein that we have named SV3 (splicing variant 3): the deduced protein sequence presents the first 49 residues identical to those of isoform 1, followed by 24 unrelated amino acids, due to a frameshift introduced at the novel exon‐exon boundary. The SV3 protein, expressed in E. coli is enzymatically inactive, most probably because unfolded, as suggested by far‐UV circular dichroism (CD) experiments. SV3 protein appears to possess the characteristics of an unstructured polypeptide chain lacking the packing of side chain residues and the secondary structure level that are typical of globular proteins. This protein could represent an inactive variant of the human LMW‐PTP.
The effect of retinoic acid on the activation of the human H19 promoter by a 3′ downstream region
Authors: Kopf E. , Bibi O. , Ayesh S. , Tykocinski M. , Vitner K. , Looijenga L.H.J. , de Groot N. , Hochberg A.
Published: July 2002

The human H19 is paternally imprinted (maternally expressed). It is transcribed by RNA pol II, but has no protein product. Its function is unknown. We showed that the transcription of the human H19 gene is under the simultaneous control of both a 5′ upstream (promoter) region and a 3′ downstream region in cell lines derived from human choriocarcinomas. Moreover, the activation of the H19 promoter by retinoic acid in cells derived from human testicular germ cell tumors is dependent upon the 3′ downstream region. The possibility that the action of retinoic acid on the H19 promoter is an indirect one and involves a member of the AP2 transcription factor family is discussed.
Sulfonylurea receptors set the maximal open probability, ATP sensitivity and plasma membrane density of KATP channels
Authors: Babenko Andrey P. , Gonzalez Gabriela , Aguilar-Bryan Lydia , Bryan Joseph
Published: July 2002

KATP channels are heteromultimers of SUR and KIR6.2. C‐terminal truncation of KIR6.2 allows surface expression of the pore. KIR6.2ΔC35 channels display ∼7‐fold lower maximal open probability, ∼35‐fold reduced ATP sensitivity, reduced mean open time, a markedly increased transition rate from a burst into a long‐lived closed state, and have no counterpart in vivo. SUR1 and SUR2A restore wild‐type bursting, ATP sensitivity and increase channel density in the plasma membrane. The high IC50(ATP) of ∼4 mM for KIR6.2ΔCK185Q channels results from the additive effects of SUR removal and KIR6.2 modification. The results demonstrate allosteric interaction(s) are essential for normal intrinsic activity, ATP inhibition, and trafficking of KATP channels.
On the binding of ATP to the autophosphorylating protein, Ptk, of the bacterium Acinetobacter johnsonii
Authors: Doublet P , Vincent C , Grangeasse C , Cozzone A.J , Duclos B
Published: July 2002

The autophosphorylating protein, Ptk, of the bacterium Acinetobacter johnsonii was overproduced, purified to homogeneity and assayed for ATP binding by using the nucleotide analog 5′‐p‐fluorosulfonylbenzoyl adenosine. The ATP binding site of this bacterial autophosphorylating protein was found to be different from that generally used by eukaryotic protein kinases. It consists of two amino acid sequences that closely resemble the Walker motifs A and B. This observation was confirmed by site‐directed mutagenesis experiments which showed, in addition, that the ATP molecule bound to these motifs is effectively employed by the bacterial protein to autophosphorylate on tyrosine. It is concluded that even though the overall autophosphorylation reaction is similar in eukaryotic and prokaryotic proteins, the mechanism involved is likely different.
Crocalbin: a new calcium‐binding protein that is also a binding protein for crotoxin, a neurotoxic phospholipase A2
Authors: Hseu Ming-Jhy , Yen Chon-Ho , Tzeng Mu-Chin
Published: July 2002

Utilizing Marathon‐ready cDNA library and a gene‐specific primer corresponding to a partial amino acid sequence determined previously, the complete nucleotide sequence for the cDNA of crocalbin, which binds crotoxin (a phospholipase A2) and Ca2+, was obtained by polymerase chain reaction. The open reading frame of the cDNA encodes a novel polypeptide of 315 amino acid residues, including a signal sequence of 19 residues. This protein contains six potential Ca2+‐binding domains, one N‐glycosylation site, and a large amount of acidic amino acid residues. The ability to bind Ca2+ has been ascertained by calcium overlay experiment. Evidenced by sequence similarity in addition, it is concluded that crocalbin is a new member of the reticulocalbin family of calcium‐binding proteins.
A distinct member of the aspartic proteinase gene family from the human malaria parasite Plasmodium falciparum
Authors: Berry Colin , Humphreys Michelle J , Matharu Philip , Granger Rachel , Horrocks Paul , Moon Richard P , Certa Uli , Ridley Robert G , Bur Daniel , Kay John
Published: July 2002

A gene (hap) transcribed during the intra‐erythrocytic life cycle stages of the human malaria parasite Plasmodium falciparum was cloned and sequenced. It was found to encode a protein belonging to the aspartic proteinase family but which carried replacements of catalytically crucial residues in the hallmark sequences contributing to the active site of this type of proteinase. Consideration is given as to whether this protein is the first known parasite equivalent of the pregnancy‐associated glycoproteins that have been documented in ungulate mammals. Alternatively, it may be operative as a new type of proteinase with a distinct catalytic mechanism. In this event, since no counterpart is known to exist in humans, it affords an attractive potential target against which to develop new anti‐malarial drugs.
Fra‐1: a novel target for retinoid action
Authors: Kaiser Astrid , Brembeck Felix H. , v. Marschall Zofia , Riecken Ernst-Otto , Wiedenmann Bertram , Rosewicz Stefan
Published: July 2002

Using a cDNA gene expression array system, we identified fra‐1 as a novel target molecule for retinoid action in the human pancreatic carcinoma cell line Dan‐G. Retinoid treatment resulted in a significant and time‐dependent induction of the fra‐1 expression on the post‐transcriptional level. Supershift assays revealed that fra‐1 participates in the activator protein 1 complex together with c‐fos, c‐jun and junB. Transient transfection experiments using a reporter plasmid containing an activator protein site upstream of the CAT reporter gene revealed that the phorbolester‐induced CAT activity was suppressed by retinoids. Since fra‐1 lacks a transactivation function, we therefore suggest that the retinoid‐mediated induction of fra‐1 might function as a negative regulator of the activator protein 1 activity in human pancreatic carcinoma cells.
Suppression of the neoplastic phenotype by transfection of phospholipase C β 3 to neuroendocrine tumor cells
Authors: Stålberg Peter , Wang Shu , Larsson Catharina , Weber Günther , Öberg Kjell , Gobl Anders , Skogseid Britt
Published: July 2002

The expression of phospholipase C β 3 (PLCB3) is low or absent in several neuroendocrine neoplasias. To investigate the role of PLCB3 in the neuroendocrine tumorigenesis, we transfected a PLCB3 construct to three neuroendocrine tumor cell lines with a low PLCB3 expression. The growth rate and tumorigenicity were assessed in vitro by [3H]thymidine incorporation and cell counting, in vivo, by xenografting to nude mice. In vitro, PLCB3 expressing clones showed a significant growth inhibition. The tumor weight was reduced for one of the two xenografted PLCB3‐transfected cell lines and in both, a reduced number of proliferating (Ki‐67 positive) cells was observed. This study implies an essential role for PLCB3 in the neuroendocrine tumorigenesis.
Nucleotide sequence of a cDNA encoding a common precursor of disintegrin flavostatin and hemorrhagic factor HR2a from the venom of Trimeresurus flavoviridis
Authors: Yamada Daisuke , Shin Yongchol , Morita Takashi
Published: July 2002

The venom of Trimeresurus flavoviridis has three disintegrins that act as platelet aggregation inhibitors by binding to integrin αIIbβ3 on platelets through its Arg‐Gly‐Asp sequence. We isolated the cDNA encoding the flavostatin precursor that is one of the disintegrins in T. flavoviridis venom. The open reading frame consisted of four regions, a pre‐peptide region, a metalloprotease region, a spacer region and a disintegrin region, indicating that the flavostatin precursor belongs to the metalloprotease/disintegrin family. Surprisingly, the deduced amino acid sequence of the metalloprotease region was completely consistent with that of hemorrhagic metalloprotease HR2a, which indicated that this metalloprotease released from the flavostatin precursor functions as a hemorrhagic factor. These observations indicated that a disintegrin and a hemorrhagic metalloprotease were synthesized as a common precursor. Thus, our results support the hypothesis that a disintegrin is synthesized as a metalloprotease/disintegrin precursor and matures by cleavage from the precursor molecule.
Flow cytometry and surface plasmon resonance analyses demonstrate that the monoclonal antibody JIM19 interacts with a rice cell surface component involved in abscisic acid signalling in protoplasts
Authors: Desikan Radhika , Hagenbeek Dik , Neill Steven J. , Rock Christopher D.
Published: July 2002

Abscisic acid (ABA) is a plant hormone involved in many developmental and physiological processes, but as yet, no ABA receptor has been identified. Flow cytometry of rice protoplasts and immunoblotting of purified plasma membranes (PMs) have been used to demonstrate that the monoclonal antibody JIM19 recognizes carbohydrate epitopes of cell surface glycoproteins. Using surface plasmon resonance technology specific binding of PMs to JIM19 was observed. Such interaction was antagonized significantly by ABA, but not by the biologically inactive ABA catabolite phaseic acid. These in vitro interactions were correlated with the biological activities of JIM19, ABA and phaseic acid on activation of the ABA‐inducible Em promoter using two different transient reporter gene assays, β‐glucuronidase/luciferase and quantitative flow cytometry of Aequoria green fluorescent protein. Pre‐treatment with JIM19 resulted in significant inhibition of ABA‐inducible gene expression. Taken together, these data suggest that JIM19 interacts with a functional PM complex involved in ABA signalling.
Procollagen binds to both prolyl 4‐hydroxylase/protein disulfide isomerase and HSP47 within the endoplasmic reticulum in the absence of ascorbate
Authors: Hosokawa Nobuko , Nagata Kazuhiro
Published: July 2002

In cells, only properly folded procollagen trimers are secreted from the endoplasmic reticulum (ER), while improperly folded abnormal procollagens are retained within the ER. Ascorbic acid is a co‐factor in procollagen hydroxylation, which in turn is required for trimer formation. We examined chaperone proteins which bound to procollagen in the absence of ascorbic acid, a model which mimics the human disease scurvy at the cellular level. We found that both prolyl 4‐hydroxylase (P4‐H)/protein disulfide isomerase (PDI) and HSP47 bound to procollagen in the absence of ascorbic acid. However, the binding of PDI to procollagen decreased when HSP47 was co‐transfected, suggesting that HSP47 and PDI compete for binding to procollagen. These data indicate that P4‐H/PDI and HSP47 have cooperative but distinct chaperone functions during procollagen biosynthesis.
Extra‐amniotic saline infusion versus extra‐amniotic prostaglandin F2α for cervical ripening and induction of labor
Authors: Mawire C.J , Chipato T , Rusakaniko S
Published: July 2002

Objective: To compare the effectiveness of extra‐amniotic saline infusion versus extra‐amniotic prostaglandin F2α for cervical ripening, induction of labor and achievement of vaginal delivery in patients with unfavorable cervices. Method: A randomized trial of extra‐amniotic saline infusion versus extra‐amniotic prostaglandin F2α performed at Harare Central Hospital Maternity Unit, Zimbabwe. One hundred and sixty‐four patients were recruited from those referred to Harare Central Hospital Maternity Unit who required induction of labor for either maternal or fetal indications. Results: 162 patients (extra‐amniotic PgF2α group, N=81; extra‐amniotic saline infusion group, N=81) had complete information. Two patients (one from each group) were lost to follow up. The demographic characteristics of the patients and the indications for induction were not statistically different. There was a marginally statistically significant difference in the change of Bishop Score in favor of the extra‐amniotic saline infusion (4.0, S.D.=1.4) as compared to (4.5, S.D.=1.5) for extra‐amniotic PgF2α (P value=0.047). All other parameters showed no statistically significant differences. Maternal and fetal complications were minimal and not significantly different. Extra‐amniotic saline infusion was however almost six times cheaper than PgF2α. Conclusion: Extra‐amniotic saline infusion is as effective as PgF2α, safe, but much cheaper than PgF2α and should be seriously considered as a method of first choice in resource‐poor settings.
Glial cell line‐derived neurotrophic factor (GDNF) as a defensive molecule for neurodegenerative disease: a tribute to the studies of Antonia Vernadakis on neuronal–glial interactions
Authors: Bohn Martha C. , Kozlowski Dorothy A. , Connor Bronwen
Published: July 2002

Research stemming from interests in neuronal–glial interactions has led to the identification of a number of novel trophic factors, such as the dopaminergic neurotrophic factor glial cell line‐derived neurotrophic factor (GDNF). Delivery of the GDNF gene to rat models of Parkinson's disease suggests a potential clinical use of GDNF gene therapy for humans with this disease. This review article briefly summarizes the history of GDNF and the effects of GDNF gene delivery prior to or after a lesion of the rat nigrostriatal system.
Expression of gabaa receptors by reactive astrocytes in explant and primary cultures of rat cns
Authors: Hösli Elisabeth , Otten U. , Hösli L.
Published: July 2002

The presence of GABAA‐receptors on astrocytes was studied in explant and primary cultures of rat cerebellum, hippocampus and spinal cord by means of immunohistochemistry. For these studies we have used the monoclonal antibody bd 17 against the β2‐ and β3‐subunits of GABAA‐receptor. In explant cultures many neurones were intensely stained with the GABAA‐receptor antibody whereas adjacent astrocytes revealed little or no immunoreactivity. In the far outgrowth zone of explant culture, however, many immunostained astrocytes were observed. In primary astrocyte cultures, only a few cells were stained by the antibody. Astrocytes which became reactive after producing an artificial scar or after addition of certain compounds such as dibutyryl cyclic AMP, interleukin‐6, basic fibroblast growth factor and kainic acid, also revealed GABAA‐receptor immunoreactivity. Furthermore, these astrocytes were intensely stained for glial fibrillary acidic protein and vimentin. From our studies we conclude that only a subpopulation of normal astrocytes are immunopositive for the GABAA‐receptor antibody whereas astrocytes which become reactive following injury of the tissue or after addition of dibutyryl cyclic AMP, the cytokine interleukin‐6, fibroblast growth factor or the neurotoxin kainic acid express GABAA‐sites.
Strychnine‐insensitive [3H] glycine binding to synaptosomal membranes from the chick retina
Authors: RodrÍGuez‐Contreras Adrián , Calderón Froylan , LóPez‐Colomé Ana María
Published: July 2002

The pharmacology and kinetics of strychnine‐insensitive [3H] glycine binding to synaptic membranes from the outer (P1) and the inner (P2) plexiform layers of chick retina was studied. Inhibition curves for glycine,d‐serine, 1‐amincyclopropanecarboxylic acid (ACPC) and strychnine were analyzed by non‐linear regression. Hill slopes for glycine andd‐serine were not different from unity, whereas those for ACPC were < 1 in both fractions, revealing heterogeneity of binding sites in these membranes. Non‐linear regression analysis of time course and saturation experiments strengthen the idea that [3H] glycine binds to more than one class of sites, with similar affinities at equilibrium. Antagonists of strychnine‐insensitive glycine receptors in the CNS did not inhibit [3H] glycine binding to these membranes, which demonstrates that NMDA receptors in the retina have different structural requirements for ligand interaction at these sites. pH affected the specific binding, in agreement with the participation of specific amino acid residues at glycine binding sites on NMDA receptors, and also with functional studies in which the modulation of affinity at this site by protons has been observed. These results support previous studies regarding CPP and MK‐801 binding, and provide evidence which indicates that the pharmacophore for glycine and other NMDA‐related ligands is distinct for the retina, compared to the CNS, mainly regarding the effects of glycine‐site antagonists.
Comparative effects of pharmacotherapy on the maintenance of cognitive function
Authors: Allain H. , Schück S. , Mauduit N. , Djemai M.
Published: July 2002

The quality of human cognitive performance appears today as one of the main components of quality of life, whatever the age. Ageing by itself and most of the diseases affecting the central nervous system alter higher brain functions such as memory, vigilance and attention. Dementia is the most acute example, with a cascade of behavioral and psychological consequences (BPSD), which are the main cause of the caregiver’s burden and need specific pharmacotherapy. In this respect, the problem will be the choice of the best drug in situations such as wandering, agitation, violence, and screaming. The psychotropics, however, should not deteriorate the already disturbed cognition of the patients. This is the reason why we propose to establish for each drug, and notably for the antipsychotics, a precise and exact ‘cognitive mapping’; in other words, to measure the effects of drugs on the different components of cognition. The results of such studies will be predictive of the future phase III clinical trials and therapeutic responses. As an illustration of this approach we shall relate two studies, TIATEM (phase I) and TIAGE (phase III/IV), leading to the determination of a good cognitive safety profile of an atypical neuroleptic drug, tiapride.
Analysis of the seasonal variation of schizophrenic births using a Kolmogorov-Smirnov type statistic
Authors: Verdoux H , Takei N , Cassou de Saint-Mathurin R , Bourgeois M
Published: July 2002

Previous studies have shown that schizophrenic patients are more likely to be born in winter or early spring months than the general population. Data on 4,207 patients with a hospital diagnosis of schizophrenia were obtained from a mailed survey to public departments of adult psychiatry in metropolitan France. For each year from 1900 to 1965, the expected monthly number of schizophrenic births was calculated and any seasonal variation of live births in the general population was taken into account. Cumulative distributions of the observed and expected number of schizophrenic births were compared using a Kolmogorov-Smirnov type statistic. The seasonal distribution of schizophrenic births was significantly different from that of the general population (P < 0.01). An excess of schizophrenic births was found in the first half of the year, with a peak in April (+ 13%).
Anxiety disorders, comorbidity, and suicide attempts in adolescence: a preliminary investigation
Authors: Pawlak C , Pascual-Sanchez T , Raë P , Fischer W , Ladame F
Published: July 2002

The prevalence of anxiety disorders and associated DSM-III-R diagnoses were measured in a sample of 80 female adolescents aged between 15 to 20 years consulting an outpatient psychiatric service for adolescents. The suicide attempt group (SA) included 40 patients evaluated within 24 h after attempted suicide. This is compared to 40 consecutive patients consulting the same center but without any history of suicide attempt (the no attempt group, NA).

The global prevalence of anxiety disorders was similar in both groups (SA: 65% vs. NA: 60%, NS) as was the relative importance of the different disorders in each group, generalized anxiety being the most frequent specific anxiety disorder. The most striking difference between the two groups was in the prevalence of affective disorders in 90% (SA) vs. 32.5% (NA) (P < 0.001), leading to high rates of comorbidity on axis I in the SA group. Of the 24 patients with anxiety disorders who attempted suicide, 21 (95%) fulfilled criteria for associated major depression, compared to five out of 21 (24%) patients with anxiety disorders who had not attempted suicide.

Adolescents with anxiety disorders developing major depression are at a high risk for suicide. The depression may be of short duration (less than two weeks) when compared to that of the anxiety disorder (greater than six months). To improve suicide prevention, our findings if confirmed should encourage clinicians to perform a close follow-up of adolescents with anxiety disorders for an early detection of sudden depressive breakdowns.
Use of medical resources and quality of life of patients with chronic heart failure: a prospective survey in a large Italian community hospital
Authors: Albanese Maria C. , Plewka Michal , Gregori Dario , Fresco Claudio , Avon Giorgio , Caliandro Donato , Grassi Libero , Rossi Paolo , Udina Paolo , Bulfoni Alessandro , Colle Roberto , Cuzzato Anna Linda , Fioretti Paolo M.
Published: July 2002

Aims:

To assess the prevalence, clinical characteristics, use of medical resources and quality of life in consecutive patients with chronic heart failure (CHF) hospitalized in a large community hospital during 3 months.

Methods and results:

The study group included 354 patients with CHF, admitted in the Departments of Internal Medicine (97%) and Cardiology. Median age was 78 years [72;85], 45% were males. CHF was the main diagnosis in 72%; 28% were in NYHA class III and 49% in class IV; 42% had atrial fibrillation. The median hospital stay was 8 days [5;14], in‐hospital mortality 9% in those admitted for CHF and 19% in those admitted primarily for other diseases. Patients with CHF occupied 15% of the beds; 1330 ECGs, 389 chest X‐rays, 112 echocardiograms and 10 coronary angiograms were performed. A quality of life questionnaire revealed that 82% had problems with mobility, 54% with self‐care and 88% with everyday activity. Thirty‐nine percent of patients had at least one hospitalization during the previous year.

Conclusions:

Ninety‐seven percent of hospitalized patients with CHF are admitted in the Internal Medicine wards and occupy 15% of beds. The majority of the patients are 72 years or older, with severe heart failure. The frequency of rehospitalization(s) and mortality rate in this population remains high. Echocardiography is performed only in 27% of patients.
“EVIDENCE” AND MIDWIFERY PRACTICE
Authors: Albers Leah L.
Published: July 2002

Evidence‐based care has become the new standard in the clinical disciplines. It represents a paradigm shift for clinicians, toward greater inclusion of research findings in patient care decisions. Randomized trials are the “gold standard” in clinical research and provide the strongest evidence for a treatment or intervention. But, randomized trials have limitations and cannot address all important clinical questions. Research using observational, descriptive, and qualitative methods also has a place in generating evidence for practice. Balancing the needs of individual women against what is learned from research with groups or populations is a challenge for midwives.
Disposition and pharmacologic effects of R/S‐verapamil in patients with chronic atrial fibrillation: An investigation comparing single and multiple dosing
Authors: Busse Dagmar , Fromm Martin F. , Mörike Klaus , Drescher Siegfried , Kühlkamp Volker , Eichelbaum Michel
Published: July 2002

Background

Racemic (R/S)‐verapamil is widely used in the management of chronic atrial fibrillation. The negative dromotropic effect is mainly mediated by the S‐enantiomer, which is preferentially metabolized. Previous studies report an accumulation of R/S‐verapamil during long‐term oral treatment of patients with chronic atrial fibrillation. However, the specific disposition of S‐verapamil and the pharmacologic effects were not assessed. Therefore uncertainties about the need for dose adjustments remain.

Methods

Using stable isotope technology and a stereospecific assay, we compared the pharmacokinetics and pharmacodynamics of intravenous (10 mg of d7‐R/S‐verapamil) and oral (240 mg of slow release (SR) d0‐R/S‐verapamil) R–verapamil and S‐verapamil after the first dose (day 1) and after 3 weeks (day 21) of continuous oral therapy in 8 patients with long‐term atrial fibrillation. On both study days, serum samples were obtained for the analysis of d7‐ and d0‐R‐verapamil and S‐verapamil. Heart rate (HR) was monitored with electrocardiography (with each blood sample) and Holter electrocardiography (before the study, on day 1, and on day 21).

Results

Compared with day 1, clearance of oral R‐verapamil and S‐verapamil was significantly reduced on day 21 (1007 ± 380 versus 651 ± 253 mL/min [–35%] and 5481 ± 2731 versus 2855 ± 1097 mL/min [–48%], respectively; P < .05), whereas only a moderate decrease was observed for intravenous R‐verapamil and S‐verapamil (–23% and −14%, respectively, not significant). Mean HR (89 ± 11 bpm before verapamil) was effectively reduced, with the same effects on day 1 (68 ± 8 bpm) and day 21 (68 ± 8 bpm). Compared with day 1, the HR reduction per ng/mL of S‐verapamil (calculated by the area under the curve [from 0–24 hours] ratio of HR reduction and S‐verapamil concentration) was significantly lower on day 21 (0.7 ± 0.4 versus 1.2 ± 0.7 [bpm] · [ng/mL]−1, for day 21 versus day 1; P < .01).

Conclusions

In patients with chronic atrial fibrillation, clearance of oral, but not intravenous, S‐verapamil and R‐verapamil is significantly reduced with multiple doses compared with a single dose, thereby indicating predominant impairment of prehepatic rather than hepatic metabolism as the underlying mechanism. However, this kinetic change is clinically compensated by a decrease in the responsiveness to S‐verapamil observed with regular dosing. The data suggest that despite accumulation of the drug individual verapamil doses can be maintained during long‐term oral rate control therapy.

Clinical Pharmacology & Therapeutics (2001) 69, 324–332; doi: 10.1067/mcp.2001.115125