bluuebunny/crossref_metadata_2025 huggingface dataset:
Homology between the pyrazine‐binding protein from nasal mucosa and major urinary proteins
Authors: Cavaggioni A. , Sorbi R.T. , Keen J.N. , Pappin D.J.C. , Findlay J.B.C.
Published: July 2002

Sequence analysis of the pyrazine‐binding protein from bovine olfactory mucosa reveals marked homology with a family of proteins of unknown function found in the urine of the adult male mouse and rat. In view of the dramatic biological responses to odorants transmitted in male rodent urines, it is proposed that these proteins play important roles in some aspects of odor transmission and reception.
B‐Z DNA conformational transition in 1:1 electrolytes: dependence upon counterion size
Authors: Soumpasis Dikeos M. , Robert-Nicoud Michel , Jovin Thomas M.
Published: July 2002

We have studied the B‐Z transition of poly[d(G‐C)] in the presence of alkali metal, tetramethylammonium and tetraethylammonium chlorides at room temperature. The measured critical salt concentrations increase in the order Na, K, Rb, TMA, Cs and are in good agreement with the theoretical values predicted from a statistical‐mechanical treatment of the transition.
D‐Penicillamine inhibits transactivation of human immunodeficiency virus type‐1 (HIV‐1) LTR by transactivator protein
Authors: Chandra A. , Demirhan I. , Arya S.K. , Chandra P.
Published: July 2002

D‐Penicillamine, an amino acid analogue of cysteine, has been shown to inhibit the transactivation of HIV‐1 LTR by the transactivator protein, tat protein. The transactivation was studied in Jurkat cells co‐transfected with plasmids containing HIV‐LTR sequences fused to the bacterial chloramphenicol acetyltransferase (CAT) gene and HIV tat gene. The expression of CAT activity was a measure of transactivation of LTR by the tat protein. Incubation of transfected Jurkat cells with D‐penicillamine led to inhibition of CAT activity. This inhibition was found to be concentration‐dependent; more than 90% inhibition of chloramphenicol acetylation was seen in extracts prepared from cultures incubated with 40 μg/ml of D‐penicillamine. Earlier experiments have shown that D‐penicillamine at 40 μg/ml can completely inhibit HIV‐1 (HTLV‐III B) replication in H9 cells [(1986) Drug Res. 36, 184–186]. These results suggest that inhibition of transactivation may be the molecular mechanism involved in the inhibition of HIV‐1 replication by D‐penicillamine.
Hepatic ethanol metabolism is mediated predominantly by catalase‐H2O2 in the fasted state
Authors: Handler Jeffrey A. , Thurman Ronald G.
Published: July 2002

Methanol and butanol were employed as selective substrates for catalase‐H2O2 and alcohol dehydrogenase (ADH), respectively, in the perfused rat liver. As expected, rates of butanol metabolism accounted for over 85% of overall rates of alcohol oxidation indicating that ADH was the predominant pathway of alcohol metabolism in both the fed or fasted state in the absence of added substrate. In the fasted state, however, addition of oleate (1 mM) diminished butanol oxidation 20–25% yet increased rates of methanol oxidation over 4‐fold. Under these conditions, methanol uptake accounted for nearly two‐thirds of overall rates of alcohol oxidation. These data demonstrate that catalase‐H2O2 is the predominant pathway of alcohol oxidation in the fasted state in the presence of fatty acids. Accordingly, it is concluded that diet and nutritional state play important roles in the contribution of the ADH and catalase pathways to alcohol oxidation.
Levels of 7α‐hydroxy‐4‐cholesten‐3‐one in plasma reflect rates of bile acid synthesis in man
Authors: Axelson M. , Aly A. , Sjövall J.
Published: July 2002

A method for analysis of 7α‐hydroxy‐4‐cholesten‐3‐one in plasma is described. Following solid‐phase extraction/purification the compound is determined by high‐performance liquid chromatography using a UV detector. The median concentration in healthy subjects was 12 ng/ml (range 3–40). The levels were lower in diseases associated with a low bile acid production: extrahepatic cholestasis, <1.5 ng/ml (range < 0.9–3); liver cirrhosis <1.5 ng/ml (range < 0.9–38), and higher in diseases associated with a high bile acid production: cholestyramine treatment, 188 ng/ml (range 54–477); ileal resection 397 ng/ml (range 128–750). The levels were essentially normal in patients with colon resection. The results are consistent with a strong positive correlation between the levels of 7α‐hydroxy‐4‐cholesten‐3‐one in plasma and the rate of bile acid synthesis.
A Ca2+ ‐stimulated, Mg2+ ‐dependent ATPase activity in subcellular fractions from Schistosoma mansoni
Authors: Cunha Valéria M.N. , de Souza Wanderley , Noël François
Published: July 2002

A Ca2+‐stimulated, Mg2+‐dependent ATPase activity was found in subcellular fractions from Schistosoma mansoni. Its specific and relative activities were higher in the heterogeneous cuticle fraction and in the microsomal fraction. The K
0.5 for ATPase activation by free Ca2+ was 0.2–0.5 μM. This is the first description of an ATPase activity stimulated by Ca2+ in the micromolar range in S. mansoni.
Carboxyatractylate inhibits the uncoupling effect of free fatty acids
Authors: Andreyev A.Yu. , Bondareva T.O. , Dedukhova V.I. , Mokhova E.N. , Skulachev V.P. , Volkov N.I.
Published: July 2002

The ATP/ADP‐antiporter inhibitors and ADP decrease the palmitate‐induced stimulation of the mitochondrial respiration in the controlled state. The degree of inhibition decreases in the order: carboxyatractylate > bongkrekic acid, palmitoyl‐CoA, ADP > atractylate. GDP is ineffective. The inhibiting concentration of carboxyatractylate coincides with this arresting the state 3 respiration. Carboxyatractylate inhibition decreases when the palmitate concentration increases. Stimulation of controlled respiration by FCCP or gramicidin D at any concentration of these uncouplers is carboxyatractylate‐resistant, whereas that by low concentrations of DNP is partially suppressed by carboxyatractylate. These data together with observations that palmitate does not increase H+ conductance in bilayer phospholipid membranes and in cytochrome oxidase‐asolectin proteoliposomes indicate that the ATP/ADP‐antiporter is somehow involved in the uncoupling by low concentrations of fatty acids (or DNP), whereas that by FCCP and gramicidin D is due to their effect on the phospholipid bilayer. It is suggested that the antiporter facilitates translocation of palmitate anion across the mitochondrial membrane.
Photoreduction of NADP+ by a chloroplast photosystem II preparation: effect of light intensity
Authors: Arnon Daniel I. , Tang George M.-S.
Published: July 2002

Recent work in this and other laboratories has demonstrated that, contrary to the favored Z scheme hypothesis, photosystem II (PS II) can photoinduce electron transfer from water to NADP+, without the participation of photosystem I (PS I). One proposed explanation for this conflict between hypothesis and observation was that PS II can reduce NADP+ but only at high light intensities. We report here findings at variance with this proposal. A PS II preparation made from spinach chloroplasts by the two‐phase aqueous polymer partition method photoreduced NADP+ without the involvement of PS I, at varying light intensities ranging from limiting to saturating.
Low temperature photochemistry and spectral properties of a photosystem 2 reaction center complex containing the proteins D1 and D2 and two hemes of Cyt b‐559
Authors: Shuvalov V.A. , Heber U. , Schreiber U.
Published: July 2002

A D1/D2/Cyt b‐559 complex isolated from spinach chloroplasts contained 4 chlorophylls, 2 pheophytins and 2 hemes of Cyt b‐559 with different redox potentials measured to be +70 mV(LP) (pH 7.2) and about −500 mV (XLP). Prereduced Cyt(LP) is photooxidized at 77 K due to the interaction with the state P680+ Ph − which produces the accumulation of Cyt+ P680 Ph−. Another Ph molecule is reduced with a midpoint potential of −450 mV and can interact with Cyt (XLP) forming a second electron transfer chain.
ESR signals of NADH and NADPH under illumination
Authors: Umrikhina A.V. , Luganskaya A.N. , Krasnovsky A.A.
Published: July 2002

ESR method was applied to investigate the formation of NADH and NADPH free radicals. It was shown that under the action of light (340 nm) in water and other solutions of these compounds a reaction occurred resulting in the formation of free radicals having the typical ESR spectrum. The analysis of the temperature dependence showed the light‐induced ESR signals to be registered at −30°C to −120°C, the most intensive ones being observed at −50°C. It was concluded that the observed ESR signals belonged to the products of one‐electron oxidation of the coenzymes‐free radicals NAD. and NADP..
The inhibition of human immunodeficiency virus type 1 reverse transcriptase by avarol and avarone derivatives
Authors: Loya Shoshana , Hizi Amnon
Published: July 2002

We have analyzed the effects of several natural compounds related to avarols and avarones on the catalytic functions of human immunodeficiency virus type 1 (HIV‐1) reverse transcriptase (RT). The most potent substances, designated as avarone A,B and E and avarol F, inhibited indiscriminately the enzymatic activities of HIV‐1 RT, namely the RNA‐dependent and DNA‐dependent DNA polymerase as well as the ribonuclease H. The inhibition of the DNA polymerase activity was found to be non‐competitive with respect to either the template‐primer or the deoxynucleotide‐triphosphate. These studies suggest that the hydroxyl group at the ortho position to the carbonyl group at the quinone ring is involved in blocking the RT activity. The identification of the active site of the inhibitors will hopefully lead to the rational design of new potent anti‐HIV drugs.
Adipogenesis inhibitory factor A novel inhibitory regulator of adipose conversion in bone marrow
Authors: Ohsumi Jun , Miyadai Kenji , Kawashima Ichiro , Ishikawa-Ohsumi Hiroko , Sakakibara Sachiko , Mita-Honjo Katsuko , Takiguchi Yo
Published: July 2002

Recombinant adipogenesis inhibitory factor (AGIF) was purified to homogeneity from the conditioned medium of COS‐1 cells transfected with human AGIF cDNA. The amino‐terminal sequence analysis of the mature AGIF revealed that AGIF was produced as a precursor consisting of 199 amino acids and processed into a mature form of 178 amino acids by a cleavage between Ala(−1) and Pro(+1). The purified AGIF inhibited the process of adipogenesis in mouse 3T3‐L1 preadipocytes, indicating that AGIF directly acts on the cells. AGIF acted as an adipogenic antagonist not only on the extramedullary cell line 3T3‐L1 but also on the mouse bone marrow stroma‐derived cell line H‐I/A, suggesting that this cytokine may regulate adipogenesis in bone marrow.
Analysis of the colchicine‐binding site of β‐tubulin
Authors: Burns Roy G.
Published: July 2002

Comparison of the β‐tubulin sequences with the equilibrium colchicine K
a and the K
i for inhibition by podophyllotoxin suggests that residue β:316 is directly involved in binding the common trimethoxyphenyl‐ (or A‐) ring. By contrast, the analysis indicates that the local hydrophobicity affects the rate of one of the two conformational changes associated with colchicine binding but does not determine the affinity of the colchicine‐binding site.
A rapid calcium influx during exocytosis in Paramecium cells is followed by a rise in cyclic GMP within 1 s
Authors: Knoll Gerd , Kerboeuf Daniel , Plattner Helmut
Published: July 2002

The synchrony of trichocyst exocytosis in Paramecium allows temporal correlation of associated events. Using quenched flow we observed a Ca2+ influx concurrent with exocytosis within 80 ms after stimulation with the secretagogue aminoethyldextran. Cyclic AMP did not change in depency of stimulation. Cyclic GMP transiently increased after 500 ms, culminating at 2 s, and thus considerably lags behind exocytosis induction and influx of Ca2+. Both Ca2+ influx and rise in cGMP are known to be induceable also by Ba2+ or veratridine, allegedly via the opening of ciliary Ca2+ channels. However, only veratridine stimulated exocytosis. We conclude that both aminoethyldextran and veratridine induce an exocytosis‐associated Ca2+ influx, which is responsible for the rise in cGMP, through an as yet unknown pathway.
Glycation of crystalline in lenses from aging and diabetic individuals
Authors: van Boekel M.A.M. , Hoenders H.J.
Published: July 2002

Water‐soluble crystallins were obtained from clear human lenses of different age(4–81‐year‐olds) and lenses of individuals showing senile and diabetic cataracts. Levels of early glycation products were high in the high molecular weight material (HM) and the α‐crystallin fractions, compared with β and γ‐crystallins. This difference becomes more prominent upon aging. The content of total early glycation products in HM and α‐crystallin increases clearly with age, whereas levels remain relatively constant in the β‐ and α‐crystallins. There is an elevation of early products in cataractous lenses from diabetic individuals compared with those suffering from senile cataract. Specific non‐tryptophan fluorescence (excitation/emission wavelengths 370/440 nm), used as an indicator for late glycation products, increased dramatically with age and was 2‐fold higher in the diabetic subjects. Levels of fluorescence decreased in the order HM > α‐ > b > γ‐crystallins. The results suggest an increase in glycation rate in α‐crystallin as a result of aging and diabetes, while the rate of glycation of β‐ and γ‐crystallins remains almost constant.
Inhibition of carnitine palmitoyltransferase I by hepatocyte swelling
Authors: Guzmán Manuel , Velasco Guillermo , Castro José , Zammit Victor A.
Published: July 2002

Incubation of hepatocytes under conditions known to increase their volume, i.e. with amino acids (glutamine, proline) or in hypo‐osmotic medium, decreased carnitine palmitoyl‐transferase I (CPT‐I) activity. This effect of hepatocyte swelling was antagonized by okadaic acid and dibutyryl‐cAMP. Physiological concentrations of glutamate inhibited CPT‐I activity in digitonin‐permeabilized hepatocytes but not in isolated mitochondria. Results suggest that the amino acid‐induced inhibition of CPT‐I shares a common mechanism with the amino acid‐induced stimulation of acetyl‐CoA carboxylase and glycogen synthase [(1993) Eur. J. Biochem. 217, 1083–1089].
Antioxidant system in rat testicular cells
Authors: Bauché Françoise , Fouchard Marie-Hélène , Jégou Bernard
Published: July 2002

The activity of the enzymes involved in the antioxidant defence — superoxide dismutase (SOD), glutathione peroxidase (GPx), reductase (GR) S‐transferase (GST) — as well as the glutathione (GSH) levels were measured in different rat testicular cell populations. A differential distribution of these components among testicular cell types was clearly observed. Sertoli and peritubular cells had elevated SOD and GSH‐dependent enzyme activities associated with a high GSH content. Compared with the somatic cells, pachytene spermatocytes (PS) round spermatids (RS) presented a different antioxidant system characterized by higher SOD activity and GSH content associated with very low GSH‐dependent enzyme activity. Spermatozoa exhibited the same enzymatic system as PS and RS but were devoid of GSH. Interstitial tissue displayed high GSH content, moderate SOD and GSH‐related enzyme activity except for GPx which was very elevated. It is concluded that the different categories of testicular cells probably display a highly variable susceptibility to oxidative stress.
Molecular identification of catalases from Nicotiana plumbaginifolia (L.)
Authors: Willekens Hilde , Villarroel Raimundo , Van Montagu Marc , Inzé Dirk , Van Camp Wim
Published: July 2002

We have isolated three different catalase cDNAs from Nicotiana plumbaginifolia (cat1, cat2, and cat3) and a partial sequence of a fourth catalase gene (cat4) that shows no discernible expression based on Northern analysis. The catalase sequences were used to determine the similarity with other plant catalases and to study the transcriptional response to paraquat, 3‐aminotriazole, and salicylic acid. 3‐Aminotriazole induces mRNA levels of cat1, cat2 and cat3, indicating that a reduction in catalase activity positively affects catalase mRNA abundance. Salicylic acid that binds catalase in vitro, had no effect on catalase transcript levels at physiological concentrations. Paraquat resulted in the induction of cat1.
Cloning and sequencing of four structural genes for the Na+‐translocating NADH‐ubiquinone oxidoreductase of Vibrio alginolyticus
Authors: Beattie P. , Tan K. , Bourne R.M. , Leach D. , Rich P.R. , Ward F.B.
Published: July 2002

Oligonucleotide probes based on the N‐terminal amino acid sequences of the NqrA and NqrC subunits were used to clone genes for the Na+‐dependent NADH‐ubiquinone oxidoreductase complex from Vibrio alginolyticus. Four consecutive ORFs were identified encoding subunit proteins of 48.6, 46.8, 27.7 and 22.6 kDa, respectively (NqrA—D). A further ORF, showing 71% homology to the BolA protein of Escherichia coli, was located upstream. From sequence comparisons, we conclude that the Na+‐dependent NADH‐ubiquinone oxidoreductase complex of V. alginolyticus is clearly distinct from the corresponding H+‐dependent enzymes of both prokaryotes and eukaryotes.
Molecular characterization of human and bovine endothelin converting enzyme (ECE‐1)
Authors: Schmidt Martin , Kröger Burkhard , Jacob Elard , Seulberger Harald , Subkowski Thomas , Otter Rainer , Meyer Thomas , Schmalzing Günther , Hillen Heinz
Published: July 2002

A membrane‐bound protease activity that specifically converts Big endothelin‐1 has been purified from bovine endothelial cells (FBHE) The enzyme was cleaved with trypsin and the peptide sequencing analysis confirmed it to be a zinc chelating metalloprotease containing the typical HEXXH (HELTH) motif. RT‐PCR and cDNA screens were employed to isolate the complete cDNAs of the bovine and human enzymes. This human metalloprotease was expressed heterologously in cell culture oocytes. The catalytic activity of the recombinant enzyme is the same as that determined for the natural enzyme. The data suggest that the characterized enzyme represents the functional human endothelin converting enzyme ECE‐1.
Alternative approaches for reducing schedule instability in multistage manufacturing under demand uncertainty
Authors: Kadipasaoglu Sukran N. , Sridharan V.
Published: July 2002

Schedule nervousness caused by uncertainty in demand or supply or by dynamic lot‐sizing can be an obstacle to effective execution of material requirements planning (MRP) systems. Previous studies on the effectiveness of alternative approaches for dampening nervousness almost always considered single‐level product structures and deterministic demand conditions. This study evaluates the effectiveness of three strategies for reducing nervousness in multi‐level MRP systems under demand uncertainty: (1) freezing, (2) end‐item safety stock, and (3) lot‐for‐lot scheduling below level 0. The strategies are evaluated under a wide range of operating conditions characterized by variations in item cost structure, product structure, demand uncertainty, and lot‐sizing methods used. A multi‐level MRP system is simulated to study the relative performance of the three strategies. Results indicate that freezing the master production schedule is the most effective approach in terms of reducing both instability and cost as the freeze length covers the cumulative lead time. It is also the least sensitive to changes in operating conditions.
Social skills training for chronic psychotic patients: A French study
Authors: Chambon O , Marie-Cardine M , Dazord A
Published: July 2002

The aim of this article is to describe the cognitive-behavioral methods for social rehabilitation and psychotherapy of chronic psychotic patients which are nowadays available in French-speaking countries, then to propose a theoretical framework to help integrate these various methods for use in our duly pratice and, finally, to expose our research in this field, especially concerning the topic of quality of life and social skills training programs. We present a study we designed in order to assess the impact of a comprehensive social skills training program upon quality of life of chronic schizophrenic patients. Starting from the point of view that a good psychosocial rehabilitation program is one that improves social skills and social functioning without negative effects on quality of life, we tried to show such qualities in a quite comprehensive rehabilitation program using social skills training methods corresponding to the social readaptative “modules” from Liberman and Wallace's Social and Independant Living Skills Program — “medication management module” — followed by “basic conversational skills module”, and finally, a brief adapted version of “interpersonal problem solving skills module”. We were able to observe the evolution of social skills and functioning of eight schizophrenic patients having benefited from this program, over a one year period, and we compared results regarding quality of life with two control groups made of schizophrenic patients, one of them having benefited from a supportive group therapy in order to study the impact of non-specific factors. The results indicate a clear dissociation between direct benefits of social skills training (knowledge, social skills, social functioning and symptomatology) which all showed a significant improvement in the experimental group, and subjective benefits (self-esteem, sense of self-efficacy, quality of life) which showed no change, as well when consider no intra-group as well as between group comparisons.
Limited caspase cleavage of human BAP31
Authors: Määttä Juha , Hallikas Outi , Welti Saara , Hildén Pekka , Schröder Jim , Kuismanen Esa
Published: July 2002

Human BAP31 was cleaved at both of its two identical caspase cleavage sites in two previously reported models of apoptosis. We show here that only the most carboxy‐terminal site is cleaved during apoptosis induced in HeLa cells by tunicamycin, tumor necrosis factor and cycloheximide, or staurosporine. Similar results were obtained in HL‐60 cells using Fas/APO‐1 antibodies, or cycloheximide. This limited cleavage, which is inhibited by several caspase inhibitors, removes eight amino acids from human BAP31 including the KKXX coat protein I binding motif. Ectopic expression of the resulting cleavage product induces redistribution of mannosidase II from the Golgi and prevents endoplasmic reticulum to Golgi transport of virus glycoproteins.
Thermodynamic analysis of the binding of galactose and poly‐N‐acetyllactosamine derivatives to human galectin‐3
Authors: Bachhawat-Sikder Kiran , Thomas Celestine J. , Surolia Avadhesha
Published: July 2002

Galectin‐3, with a wide tissue distribution and marked developmental regulation, provides significant insights into the progression of various disease and developmental stages. Recognized by its specificity for galactose, a detailed characterization of its sugar binding ability has been investigated by isothermal titration calorimetry. The results presented here complement well with the earlier studies utilizing hapten inhibition assays. Among the various lactose derivatives studied, A‐tetrasaccharide emerged with the highest affinity for binding to galectin‐3 combining site. This blood group saccharide exhibited a binding affinity 37‐fold higher and a 102 kJ/mol more favorable change in enthalpy over lactose at 280 K indicating the existence of additional subsites for both the α1‐3‐linked N‐acetylgalactosamine at the non‐reducing end and the α1‐2‐linked L‐fucosyl residue. The thermodynamic parameters evaluated for other ligands substantiate further the carbohydrate recognition domain to be part of an extended binding site. Binding thermodynamics of galectin‐3 with the galactose derivatives are essentially enthalpically driven and exhibit compensatory changes in ΔH° and TΔS owing to solvent reorganization.
Studies of high thermostability and peroxidase activity of recombinant antibody L chain‐porphyrin Fe(III) complex
Authors: Kohda Katsunori , Kakehi Masao , Ohtsuji Yoshiaki , Tagaki Masahiro , Imanaka Tadayuki
Published: July 2002

A complex of an independent L chain from anti‐meso‐tetrakis (4‐carboxyphenyl) porphyrin (TCPP) monoclonal antibody 13‐1 and TCPP Fe(III) was designated as L‐zyme and shown to exhibit high peroxidase activity and high optimal reaction temperature (90°C). Heat denaturation study and circular dichroism (CD) spectra analysis suggested that refolded structure of 13‐1 L chain exhibited significantly reduced inactivation rate after heat treatment. The secondary structure of 13‐1 L chain changed slightly by the encapsulation of TCPP Fe(III) and the complex was found to be less thermostable than the L chain alone. Furthermore, by characterization of truncated forms of the L chain, it was revealed that the hydrophobic region (115–146) and hydrophilic region (147–189) in Cl are important for thermostability and activity, respectively. Tertiary structure of L‐zyme was predicted by AbM. Comparison of residues of L‐zyme with those in the active centre of known structure of the peroxidase from Arthromyces ramosus (ARP) indicated that His38(CDR1), His94(CDR3), Arg96(CDR3) of L‐zyme are important residues for peroxidase activity. Moreover, the steric arrangements of these residues in both L‐zyme and ARP are similar, respectively. Distance between proximal His and distal His in L‐zyme is 9.09 Å, whereas that of ARP is 7.8 Å.
Cationic cholesterol with a hydroxyethylamino head group promotes significantly liposome‐mediated gene transfection
Authors: Okayama Ryosuke , Noji Masahide , Nakanishi Mamoru
Published: July 2002

A novel cationic cholesterol derivative with a hydroxyethylamino head group, cholesteryl‐3β‐carboxyamidoethylene‐N‐hydroxyethylamine (II), has been synthesized and used for liposome‐mediated gene transfection. The cationic liposomes containing the derivative (II) facilitated greatly pSV2CAT gene transfection into mouse NIH3T3 and L929 cells in the absence of serum. The transfection efficiency was much higher than those by the cationic liposomes containing cationic derivatives with a dialkylamino head group (I, III or IV). Further, the efficiency by the cationic liposomes with the derivative (II) was not so much decreased in the presence of serum. This suggested that a novel cationic cholesterol derivative (II) should be very promising in liposome‐mediated gene transfection of plasmid and antisense DNA into target cells.
Allelic polymorphisms in the transcriptional regulatory region of apolipoprotein E gene
Authors: Artiga Marı́a J , Bullido Marı́a J , Sastre Isabel , Recuero Marı́a , Garcı́a Miguel A , Aldudo Jesús , Vázquez Jesús , Valdivieso Fernando
Published: July 2002

In this work, we explored the existence of genetic variants within the apolipoprotein E gene transcriptional regulatory region, using a denaturing gradient gel electrophoresis screening of a region comprising nucleotides −1017 to +406. Upon a population study, three new polymorphic sites (−491, −427 and −219) and two mutations were found. Functional effects of the polymorphisms, assayed by transient transfection and electrophoretic mobility shift assays in a human hepatoma cell line, showed that polymorphisms at sites −491 and −219 of the APOE promoter produce variations in the transcriptional activity of the gene, most probably through differential binding of nuclear proteins.
Increased flux of free radicals in cells subjected to hyperthermia: detection by electron paramagnetic resonance spin trapping
Authors: Flanagan Shawn W , Moseley Pope L , Buettner Garry R
Published: July 2002

It has been hypothesized that hyperthermia promotes oxygen‐centered free radical formation in cells; however, to date there is no direct evidence of this heat‐induced increase in oxygen free radical flux. Using electron paramagnetic resonance (EPR) spin trapping, we sought direct evidence for free radical generation during hyperthermia in intact, functioning cells. Rat intestinal epithelial cell monolayers were exposed to 45°C for 20 min, after which the nitrone spin trap 5,5‐dimethyl‐1‐pyrroline N‐oxide (DMPO) was added. Compared to control cells at 37°C, heat‐exposed cells had increased free radical EPR signals, consistent with the formation of DMPO/⋅OH (aN=aH=14.9 G). These findings indicate that heat increases the flux of cellular free radicals and support the hypothesis that increased generation of oxygen‐centered free radicals and the resultant oxidative stress may mediate in part, heat‐induced cellular damage.
The M2 channel of influenza A virus: a molecular dynamics study
Authors: Zhong Qingfeng , Husslein Thomas , Moore Preston B. , Newns Dennis M. , Pattnaik Pratap , Klein Michael L.
Published: July 2002

Molecular dynamics simulations have been performed on a tetramer of the 25‐residue (SSDPLVVAASIIGILHLILWILDRL) synthetic peptide [1] which contains the transmembrane domain of the influenza A virus M2 coat protein. The peptide bundle was initially assembled as a parallel α‐helix bundle in the octane portion of a phase separated water/octane system, which provided a membrane‐mimetic environment. A 4‐ns dynamics trajectory identified a left‐handed coiled coil state of the neutral bundle, with a water filled funnel‐like structural motif at the N‐terminus involving the long hydrophobic sequence. The neck of the funnel begins at V27 and terminates at H37, which blocks the channel. The C‐terminus is held together by inter‐helix hydrogen bonds and contains water below H37. Solvation of the S23 and D24 residues, located at the rim of the funnel, appears to be important for stability of the structure. The calculated average tilt of the helices in the neutral bundle is 27±5°, which agrees well with recent NMR data.
Parasin I, an antimicrobial peptide derived from histone H2A in the catfish, Parasilurus asotus
Authors: Park In Yup , Park Chan Bae , Kim Mi Sun , Kim Sun Chang
Published: July 2002

In response to epidermal injury, Parasilurus asotus, a catfish, secreted a strong antimicrobial peptide into the epithelial mucosal layer. The molecular mass of the antimicrobial peptide, named parasin I, was 2000.4 Da, as determined by matrix‐associated laser desorption ionization mass spectrometry. The complete amino acid sequence of parasin I, which was determined by automated Edman degradation, was Lys‐Gly‐Arg‐Gly‐Lys‐Gln‐Gly‐Gly‐Lys‐Val‐Arg‐Ala‐Lys‐Ala‐Lys‐Thr‐Arg‐Ser‐Ser. Eighteen of the 19 residues in parasin I were identical to the N‐terminal of buforin I, a 39‐residue antimicrobial peptide derived from the N‐terminal of toad histone H2A [Kim et al. (1996) Biochem. Biophys. Res. Commun. 229, 381–387], which implies that parasin I was cleaved off from the N‐terminal of catfish histone H2A. Parasin I showed strong antimicrobial activity, about 12–100 times more potent than magainin 2, against a wide spectrum of microorganisms, without any hemolytic activity. Circular dichroism spectra of parasin I indicated a structural content of 11% α‐helix, 33% β‐sheet, and 56% random coils. The β‐sheet axial projection diagram of parasin I showed an amphipathic structure. Our results indicate that the catfish may produce parasin I from its histone H2A by a specific protease upon injury to protect against invasion by microorganisms.
Cardiac specific expression of the green fluorescent protein during early murine embryonic development
Authors: Fleischmann M , Bloch W , Kolossov E , Andressen C , Müller M , Brem G , Hescheler J , Addicks K , Fleischmann B.K
Published: July 2002

We demonstrate the establishment of transgenic mice, where the expression of the green fluorescent protein (GFP) is under control of the human cardiac α‐actin promoter. These mice display cardiac specific GFP expression already during early embryonic development. Prominent GFP fluorescence was observed at the earliest stage of the murine heart anlage (E8). Cardiomyocytes of different developmental stages proved GFP positive, but the intensity varied between cells. We further show that contractions of single GFP positive cardiomyocytes can be monitored within the intact embryo. At later stages of embryonic development, the skeletal musculature was also GFP positive, in line with the known expression pattern of cardiac α‐actin. The tissue specific labeling of organs is a powerful new tool for embryological as well as functional investigations in vivo.
Cloning of a novel kinase (SIK) of the SNF1/AMPK family from high salt diet‐treated rat adrenal1
Authors: Wang Zhi-nong , Takemori Hiroshi , Halder Sunil K , Nonaka Yasuki , Okamoto Mitsuhiro
Published: July 2002

PCR‐coupled cDNA subtraction hybridization was adapted to identify the genes expressed in the adrenocortical tissues from high salt diet‐treated rat. A novel cDNA clone, termed alt‐nducible inase (SIK), encoding a polypeptide (776 amino acids) with significant similarity to protein serine/threonine kinases in the SNF1/AMPK family was isolated. An in vitro kinase assay demonstrated that SIK protein had autophosphorylation activity. Northern blot revealed that SIK mRNA levels were markedly augmented by ACTH treatment both in rat adrenal glands and in Y1 cells. SIK may play an important role in the regulation of adrenocortical functions in response to high plasma salt and ACTH stimulation.
A plant‐like vacuolar H+‐pyrophosphatase in Plasmodium falciparum
Authors: Luo Shuhong , Marchesini Norma , Moreno Silvia N.J. , Docampo Roberto
Published: July 2002

Inorganic pyrophosphate promoted the acidification of a subcellular compartment in cell homogenates of Plasmodium falciparum trophozoites. The proton gradient driven by pyrophosphate was collapsed by addition of NH4Cl or the K+/H+ exchanger nigericin and eliminated by the pyrophosphate analog aminomethylenediphosphonate. Pyrophosphatase activity was dependent upon K+, and partially inhibited by Na+. The presence of a plant‐like vacuolar H+‐translocating pyrophosphatase (V‐H+‐PPase) was confirmed using antibodies raised against conserved peptide sequences of the enzyme, which cross reacted with a protein band of 76.5 kDa. Immunofluorescence microscopy using these antibodies showed a general fluorescence over the whole parasites and intracellular bright spots suggesting a vesicular and plasma membrane localization. Together, these results indicate the presence in P. falciparum of a V‐H+‐PPase of similar characteristics to those of the enzyme from plants.
Dystocia: a study of its frequency and risk factors in seven cities of west Africa
Authors: Ould El Joud D. , Bouvier‐Colle M.‐H.
Published: July 2002

Objectives: To determine the incidence of dystocia in seven west African cities, to attempt to discover what, if any, factors at the prenatal visit might identify women at risk of dystocia, and to assess the utility of such screening. Method: This prospective population study of 20 326 pregnant women in west Africa (MOMA) analyzed risk factors for dystocia on the basis of deliveries in health care facilities. Results: Incidence of dystocia was 18.3%. In the multivariate analysis, the risk factors were small stature, previous cesarean, and nulliparity. As screening tools these factors have inadequate positive predictive values, either singly or combined. Conclusion: It is almost impossible to predict the occurrence of dystocia before the onset of labor. Therefore, labor must be carefully monitored, and there must be health care facilities available that can manage complications, especially cesarean deliveries. If such facilities are not accessible, an effective referral system must be established.
Epidemiology of eclampsia in Colombia
Authors: Conde‐Agudelo A. , Kafury‐Goeta A.C.
Published: July 2002

Objective: To measure the incidence of eclampsia, its maternal and perinatal outcomes and patterns of presentation of this disease in our environment. Method: Retrospective descriptive study of 164 cases of eclampsia managed at the Hospital Universitario del Valle, Cali, Colombia from September 1993 to August 1995. Information was collected from reviews of hospital case‐notes. Results: The incidence of eclampsia was 8.1/1000 deliveries. Maternal mortality was 6.1%. Fifty‐seven percent of seizures occurred antepartum, 22% during labor, and 21% after delivery. Sixty‐nine cases (42%) presented preterm. Ninety‐eight women (60%) were nulliparous. Approximately one quarter of the women did not have hypertension or significant proteinuria at the time of seizures. Twenty percent of all women had at least one major complication. Perinatal mortality was 12.8%. Antepartum and postpartum cases were more severe than intrapartum cases. Conclusion: Eclampsia occurs in one in 124 deliveries in Cali, Colombia and is associated with high maternal and perinatal morbidity and mortality.
Aspiration and microscopy in the diagnosis of ectopic pregnancy
Authors: Lipscomb G.H , Gildner K , Shulman L.P , Eltorky M , McCord M.L , Ling F.W
Published: July 2002

Objective: To compare Karman cannula aspiration followed by dissecting microscopy with suction curettage and permanent histology in obtaining and identifying chorionic villi. Methods: Karman cannula aspiration was performed before standard curettage for failed intrauterine pregnancies (N=22) or possible ectopic gestation (N=24). Dissection microscopy for chorionic villi was performed on aspirates before submission for permanent histology. Sensitivity, specificity, positive and negative predictive value of each method in obtaining and identifying villi was determined. Results: Overall, all methods were only moderately sensitive in detecting chorionic villi (50–76%). If failed intrauterine pregnancies were excluded, all methods had poor sensitivity (25–64%). However, if villi were detected, the positive predictive value of all methods was high (>80%). Conclusions: Karman cannula aspiration followed by dissecting microscope examination or permanent histology may offer an alternative to traditional curettage in the diagnosis of ectopic gestations. A larger trial to validate these findings seems justified.
Flexible bed allocation and performance in the intensive care unit
Authors: Seung‐Chul Kim , Ira Horowitz , Karl K Young , Thomas A Buckley
Published: July 2002

The beds of an intensive care unit (ICU) are a scarce resource. Stochastic patient demands for these beds and stochastic service times in their utilization make managing that resource a complex problem lacking an easy solution. The current practice in one Hong Kong hospital is for the ICU administrator to exploit the fact that there are some patients whose admission to the unit can be postponed. These are patients scheduled for an elective surgery that can be cancelled. One way to minimize the number of cancelled surgeries is to reserve some of the unit's beds for the exclusive use of the elective‐surgery patients. We evaluate various bed‐reservation schemes via a simulation model that is based on this ICU's historical data, and demonstrate the tradeoffs that each requires among various relevant system‐performance measures. We further show how this information can be summarized in a classic efficient frontier. This frontier provides a useful medium through which the ICU administrator can communicate the rationale behind the chosen bed‐allocation system to the surgeons and the ICU physicians, in an attempt to resolve the potential conflicts between them.
Competitive priorities and managerial performance: a taxonomy of small manufacturers
Authors: Kathuria Ravi
Published: July 2002

Much of the research in manufacturing strategy has focused on specific relationships between a few constructs, with relatively little emphasis on typologies and taxonomies [Bozarth, C., McDermott, C., 1998. Configurations in manufacturing strategy: a review and directions for future research. Journal of Operations Management 16 (4) 427–439]. Using data from 196 respondents in 98 manufacturing units, this study develops a taxonomy of small manufacturers based on their emphasis on several competitive priorities. The annual sales for 64% of the participating units in this study are below US$50 million, which is on the lower side as compared to other studies in this area [cf., Miller, J.G., Roth, A.V., 1994. A taxonomy of manufacturing strategies. Management Science 40 (3) 285–304]. The study findings indicate that different groups of manufacturers — Do All, Speedy Conformers, Efficient Conformers, and Starters — emphasize different sets of competitive priorities, even within the same industry. Further, the Do All types, who emphasize all four competitive priorities, seem to perform better on customer satisfaction than their counterparts in the Starters group. The above findings lend support to the sandcone model but contradict the traditional trade‐off model.
Determinants of purchasing team usage in the supply chain
Authors: Johnson P. Fraser , Klassen Robert D. , Leenders Michiel R. , Fearon Harold E.
Published: July 2002

Increased attention on supply chain management has highlighted the pivotal role that supply chain management and purchasing teams can play in the overall competitiveness of many firms. This paper presents findings from an exploratory study that analyzes the impact of purchasing’s strategic role, industry context and purchasing organizational structure, on the use of various forms of purchasing teams. Using survey data from a broad sample of industries, we found that team usage was a two‐dimensional construct: internal teams and councils, and customer teams. In addition, purchasing’s strategic role comprised two factors: product and technology planning, and external systems planning. After controlling for firm size, purchasing’s strategic role was positively related to the greater use of internal teams and councils, but not customer teams. Industry context also played a role in the usage of teams, with internal teams and councils more extensively used by the firms that manufactured discrete goods. Meanwhile, firms in the service sector favored the use of customer teams. Finally, both industry context and purchasing’s organizational structure were related to the strategic role assumed by purchasing, with a decentralized structure tending to reduce that strategic role.
The internationalization process model through the lens of the global color picture tube industry
Authors: Khurana Anil , Talbot Brian
Published: July 2002

Internationalization theories from economics and international business disciplines suggest that products are launched, and production facilities established, sequentially in industrialized, newly industrialized, and finally, in developing countries. From a firm level perspective, operations management researchers have proposed descriptive models of generic roles of international factories. But little has appeared in the economics, international business, or operations management literature that compares these two views or provides much empirical evidence to support divergent claims. In this paper, we compare both perspectives and shed insight into factory roles through a detailed examination of data on plant practices and performance in the global picture tube industry. Our analysis suggests that existing theory and descriptive models do not possess enough explanatory power to adequately predict or describe the dynamics of product and production loci today. We highlight the need for a new theory by contrasting today's global business realities with those of yesteryears.
Explaining manufacturing technology use, firm size and performance using a multidimensional view of technology
Authors: Swamidass Paul M , Kotha Suresh
Published: July 2002

This study examines the relationships among the variables Advanced Manufacturing Technology (AMT) use, Firm Size, and Performance in US manufacturing firms using a multidimensional definition of AMT. The study's four major findings are based on empirical analyses of survey data collected from 160 manufacturing firms. First, evidence indicates that there are at least four dimensions of AMT including: Information Exchange and Planning Technology (IEPT), Product Design Technology (PDT), High‐Volume Automation Technology (HVAT), and Low‐Volume Flexible Automation Technology (LVFAT). This brings to light a key difference between the literature and the four empirically determined dimensions of AMT: empirical dimensions include two distinct dimensions for shop floor technology while most conceptual schemes do not. Second, AMT use across three of these dimensions increases linearly as firm size increases logarithmically; however, the use of some dimensions of AMT increase more rapidly with firm size than others. Third, AMT use does not show any direct impact on firm performance. Finally, firm size weakly moderates the AMT‐performance relationship; perhaps, due to their superior resource base, larger firms are able to use AMTs more effectively.
Supply chain benefits from advanced customer commitments
Authors: Gilbert Stephen M , Ballou Ronald H
Published: July 2002

Buyers are frequently encouraged through price discounts to buy in certain ways — purchase in large quantities or purchase in advance of their needs. Ideally, these pricing incentives can lead to lower costs for both the buyer and the seller. In this paper, a situation is examined where a steel distributor faces stiff competition in its highly undifferentiated service offerings and price is the primary factor in attracting sales. A model is developed that quantifies the benefits to the supplier from obtaining advanced commitments from downstream customers. This model can be used to suggest the maximum price discount that can be offered to customers to encourage them to commit to their orders in advance. Careful balancing of the advanced ordering time with the price discount can lead to cost reductions for both members of the supply channel.
Both retinoic acid and 1,25(OH)2 vitamin D3 inhibit thyroid hormone‐induced terminal differentiaton of growth plate chondrocytes
Authors: Ballock R. Tracy , Zhou Xiaolan , Mink Lynn M. , Chen Daniel H. C. , Mita Barry C.
Published: July 2002

Thyroid hormone has been known for over 50 years to be a potent regulator of skeletal maturation at the growth plate. The receptor for thyroid hormone has been discovered to be a member of the nuclear hormone receptor superfamily. Retinoic acid and 1,25(OH)2 vitamin D3, whose receptors also belong to this nuclear hormone receptor family, have been implicated in the control of chondrocyte proliferation and differentiation at the growth plate. Recent studies demonstrate that the receptors for thyroid hormone, retinoic acid, and vitamin D bind to a similar DNA response element in the promoter region of target genes and may form heterodimers to regulate gene transcription in target cells. These observations led us to hypothesize that the retinoic acid and/or vitamin D signaling pathways may interact with thyroid hormone signaling at the molecular level to modulate growth plate chondrocyte differentiation. Using a chemically defined, serum‐free model of growth plate chondrocyte maturation, both all‐trans retinoic acid and 1,25(OH)2 vitamin D3 markedly inhibited thyroid hormone‐induced terminal differentiation in a dose‐dependent manner. In the absence of thyroid hormone, retinoic acid stimulated alkaline phosphatase activity modestly at the highest dose used, however neither retinoic acid nor 1,25(OH)2 vitamin D3 induced expression of type X collagen mRNA. We conclude that retinoic acid and vitamin D are likely to be antagonists of thyroid hormone signaling in the growth plate. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.