bluuebunny/crossref_metadata_2025 huggingface dataset:
Context‐dependent effects of proline residues on the stability and folding pathway of ubiquitin
Authors: Crespo Maria D. , Platt Geoffrey W. , Bofill Roger , Searle Mark S.
Published: November 2004

Substitution of trans‐proline at three positions in ubiquitin (residues 19, 37 and 38) produces significant context‐dependent effects on protein stability (both stabilizing and destabilizing) that reflect changes to a combination of parameters including backbone flexibility, hydrophobic interactions, solvent accessibility to polar groups and intrinsic backbone conformational preferences. Kinetic analysis of the wild‐type yeast protein reveals a predominant fast‐folding phase which conforms to an apparent two‐state folding model. Temperature‐dependent studies of the refolding rate reveal thermodynamic details of the nature of the transition state for folding consistent with hydrophobic collapse providing the overall driving force. Brønsted analysis of the refolding and unfolding rates of a family of mutants with a variety of side chain substitutions for P37 and P38 reveals that the two prolines, which are located in a surface loop adjacent to the C terminus of the main α‐helix (residues 24–33), are not significantly structured in the transition state for folding and appear to be consolidated into the native structure only late in the folding process. We draw a similar conclusion regarding position 19 in the loop connecting the N‐terminal β‐hairpin to the main α‐helix. The proline residues of ubiquitin are passive spectators in the folding process, but influence protein stability in a variety of ways.
Three‐dimensional structure of a thermostable native cellobiohydrolase, CBH IB, and molecular characterization of the cel7 gene from the filamentous fungus, Talaromyces emersonii
Authors: Grassick Alice , Murray Patrick G. , Thompson Roisin , Collins Catherine M. , Byrnes Lucy , Birrane Gabriel , Higgins Timothy M. , Tuohy Maria G.
Published: November 2004

The X‐ray structure of native cellobiohydrolase IB (CBH IB) from the filamentous fungus Talaromyces emersonii, PDB 1Q9H, was solved to 2.4 Å by molecular replacement. 1Q9H is a glycoprotein that consists of a large, single domain with dimensions of ≈ 60 Å × 40 Å × 50 Å and an overall β‐sandwich structure, the characteristic fold of Family 7 glycosyl hydrolases (GH7). It is the first structure of a native glycoprotein and cellulase from this thermophilic eukaryote. The long cellulose‐binding tunnel seen in GH7 Cel7A from Trichoderma reesei is conserved in 1Q9H, as are the catalytic residues. As a result of deletions and other changes in loop regions, the binding and catalytic properties of T. emersonii 1Q9H are different. The gene (cel7) encoding CBH IB was isolated from T. emersonii and expressed heterologously with an N‐terminal polyHis‐tag, in Escherichia coli. The deduced amino acid sequence of cel7 is homologous to fungal cellobiohydrolases in GH7. The recombinant cellobiohydrolase was virtually inactive against methylumberiferyl‐cellobioside and chloronitrophenyl‐lactoside, but partial activity could be restored after refolding of the urea‐denatured enzyme. Profiles of cel7 expression in T. emersonii, investigated by Northern blot analysis, revealed that expression is regulated at the transcriptional level. Putative regulatory element consensus sequences for cellulase transcription factors have been identified in the upstream region of the cel7 genomic sequence.
Structural studies of the capsular polysaccharide and lipopolysaccharide O‐antigen of Aeromonas salmonicida strain 80204‐1 produced under in vitro and in vivo growth conditions
Authors: Wang Zhan , Larocque Suzon , Vinogradov Evgeny , Brisson Jean‐Robert , Dacanay Andrew , Greenwell Marshall , Brown Laura L. , Li Jianjun , Altman Eleonora
Published: November 2004

Aeromonas salmonicida is a pathogenic aquatic bacterium and the causal agent of furunculosis in salmon. In the course of this study, it was found that when grown in vitro on tryptic soy agar, A. salmonicida strain 80204‐1 produced a capsular polysaccharide with the identical structure to that of the lipopolysaccharide O‐chain polysaccharide. A combination of 1D and 2D NMR methods, including a series of 1D analogues of 3D experiments, together with capillary electrophoresis‐electrospray MS (CE‐ES‐MS), compositional and methylation analyses and specific modifications was used to determine the structure of these polysaccharides. Both polymers were shown to be composed of linear trisaccharide repeating units consisting of 2‐acetamido‐2‐deoxy‐d‐galacturonic acid (GalNAcA), 3‐[(N‐acetyl‐L‐alanyl)amido]‐3,6‐dideoxy‐d‐glucose{3‐[(N‐acetyl‐l‐alanyl)amido]‐3‐deoxy‐d‐quinovose, Qui3NAlaNAc} and 2‐acetamido‐2,6‐dideoxy‐d‐glucose (2‐acetamido‐2‐deoxy‐d‐quinovose, QuiNAc) and having the following structure: [→3)‐α‐d‐GalpNAcA‐(1→3)‐β‐d‐QuipNAc‐(1→4)‐β‐d‐Quip3NAlaNAc‐(1‐]n, where GalNAcA is partly presented as an amide and AlaNAc represents N‐acetyl‐l‐alanyl group. CE‐ES‐MS analysis of CPS and O‐chain polysaccharide confirmed that 40% of GalNAcA was present in the amide form. Direct CE‐ES‐MS/MS analysis of in vivo cultured cells confirmed the formation of a novel polysaccharide, a structure also formed in vitro, which was previously undetectable in bacterial cells grown within implants in fish, and in which GalNAcA was fully amidated.
Crystal structure of heme oxygenase‐1 from cyanobacterium Synechocystis sp. PCC 6803 in complex with heme
Authors: Sugishima Masakazu , Migita Catharina T. , Zhang Xuhong , Yoshida Tadashi , Fukuyama Keiichi
Published: November 2004

Heme oxygenase (HO) catalyzes the oxidative degradation of heme utilizing molecular oxygen and reducing equivalents. In photosynthetic organisms, HO functions in the biosynthesis of such open‐chain tetrapyrroles as phyto‐chromobilin and phycobilins, which are involved in the signal transduction for light responses and light harvesting for photosynthesis, respectively. We have determined the first crystal structure of a HO‐1 from a photosynthetic organism, Synechocystis sp. PCC 6803 (Syn HO‐1), in complex with heme at 2.5 Å resolution. Heme–Syn HO‐1 shares a common folding with other heme–HOs. Although the heme pocket of heme–Syn HO‐1 is, for the most part, similar to that of mammalian HO‐1, they differ in such features as the flexibility of the distal helix and hydrophobicity. In addition, 2‐propanol derived from the crystallization solution occupied the hydrophobic cavity, which is proposed to be a CO trapping site in rat HO‐1 that suppresses product inhibition. Although Syn HO‐1 and mammalian HO‐1 are similar in overall structure and amino acid sequence (57% similarity vs. human HO‐1), their molecular surfaces differ in charge distribution. The surfaces of the heme binding sides are both positively charged, but this patch of Syn HO‐1 is narrow compared to that of mammalian HO‐1. This feature is suited to the selective binding of ferredoxin, the physiological redox partner of Syn HO‐1; the molecular size of ferredoxin is ≈ 10 kDa whereas the size of NADPH‐cytochrome P450 reductase, a reducing partner of mammalian HO‐1, is ≈ 77 kDa. A docking model of heme–Syn HO‐1 and ferredoxin suggests indirect electron transfer from an iron–sulfur cluster in ferredoxin to the heme iron of heme–Syn HO‐1.
Surface exposed amino acid differences between mesophilic and thermophilic phosphoribosyl diphosphate synthase
Authors: Hove‐Jensen Bjarne , McGuire James N.
Published: November 2004

The amino acid sequence of 5‐phospho‐α‐d‐ribosyl 1‐diphosphate synthase from the thermophile Bacillus caldolyticus is 81% identical to the amino acid sequence of 5‐phospho‐α‐d‐ribosyl 1‐diphosphate synthase from the mesophile Bacillus subtilis. Nevertheless the enzyme from the two organisms possesses very different thermal properties. The B. caldolyticus enzyme has optimal activity at 60–65 °C and a half‐life of 26 min at 65 °C, compared to values of 46 °C and 60 s at 65 °C, respectively, for the B. subtilis enzyme. Chemical cross‐linking shows that both enzymes are hexamers. Vmax is determined as 440 µmol·min−1·mg protein−1and Km values for ATP and ribose 5‐phosphate are determined as 310 and 530 µm, respectively, for the B. caldolyticus enzyme. The enzyme requires 50 mm Pi as well as free Mg2+ for maximal activity. Manganese ion substitutes for Mg2+, but only at 30% of the activity obtained with Mg2+. ADP and GDP inhibit the B. caldolyticus enzyme in a cooperative fashion with Hill coefficients of 2.9 for ADP and 2.6 for GDP. Ki values are determined as 113 and 490 µm for ADP and GDP, respectively. At low concentrations ADP inhibition is linearly competitive with respect to ATP. A predicted structure of the B. caldolyticus enzyme based on homology modelling with the structure of B. subtilis 5‐phospho‐α‐d‐ribosyl 1‐diphosphate synthase shows 92% of the amino acid differences to be on solvent exposed surfaces in the hexameric structure.
Regulation of the actin–myosin interaction by titin
Authors: Niederländer Nicolas , Raynaud Fabrice , Astier Catherine , Chaussepied Patrick
Published: November 2004

Titin is known to interact with actin thin filaments within the I‐band region of striated muscle sarcomeres. In this study, we have used a titin fragment of 800 kDa (T800) purified from striated skeletal muscle to measure the effect of this interaction on the functional properties of the actin–myosin complex. MALDI‐TOF MS revealed that T800 contains the entire titin PEVK (Pro, Glu, Val, Lys‐rich) domain. In the presence of tropomyosin–troponin, T800 increased the sliding velocity (both average and maximum values) of actin filaments on heavy‐meromyosin (HMM)‐coated surfaces and dramatically decreased the number of stationary filaments. These results were correlated with a 30% reduction in actin‐activated HMM ATPase activity and with an inhibition of HMM binding to actin N‐terminal residues as shown by chemical cross‐linking. At the same time, T800 did not affect the efficiency of the Ca2+‐controlled on/off switch, nor did it alter the overall binding energetics of HMM to actin, as revealed by cosedimentation experiments. These data are consistent with a competitive effect of PEVK domain‐containing T800 on the electrostatic contacts at the actin–HMM interface. They also suggest that titin may participate in the regulation of the active tension generated by the actin–myosin complex.
Inhibition of pea ferredoxin–NADP(H) reductase by Zn‐ferrocyanide
Authors: Catalano Dupuy Daniela L. , Rial Daniela V. , Ceccarelli Eduardo A.
Published: November 2004

Ferredoxin–NADP(H) reductases (FNRs) represent a prototype of enzymes involved in numerous metabolic pathways. We found that pea FNR ferricyanide diaphorase activity was inhibited by Zn2+ (Ki 1.57 µm). Dichlorophenolindophenol diaphorase activity was also inhibited by Zn2+ (Ki 1.80 µm), but the addition of ferrocyanide was required, indicating that the inhibitor is an arrangement of both ions. Escherichia coli FNR was also inhibited by Zn‐ferrocyanide, suggesting that inhibition is a consequence of common structural features of these flavoenzymes. The inhibitor behaves in a noncompetitive manner for NADPH and for artificial electron acceptors. Analysis of the oxidation state of the flavin during catalysis in the presence of the inhibitor suggests that the electron‐transfer process between NADPH and the flavin is not significantly altered, and that the transfer between the flavin and the second substrate is mainly affected. Zn‐ferrocyanide interacts with the reductase, probably increasing the accessibility of the prosthetic group to the solvent. Ferredoxin reduction was also inhibited by Zn‐ferrocyanide in a noncompetitive manner, but the observed Ki was about nine times higher than those for the diaphorase reactions. The electron transfer to Anabaena flavodoxin was not affected by Zn‐ferrocyanide. Binding of the apoflavodoxin to the reductase was sufficient to overcome the inhibition by Zn‐ferrocyanide, suggesting that the interaction of FNRs with their proteinaceous electron partners may induce a conformational change in the reductase that alters or completely prevents the inhibitory effect.
Application of liquid chromatography–mass spectrometry to monitoring plasma cyclophosphamide levels in phase I trial cancer patients*
Authors: Liu Johnson J , Kestell Philip , Findlay Michael , Riley Greta , Ackland Stephen , Simpson Andrew , Isaacs Richard , McKeage Mark J
Published: November 2004

1. A specific and efficient liquid chromatography–mass spectrometry (LC‐MS) method was established for monitoring patient plasma cyclophosphamide levels in a phase I trial of an oral cyclophosphamide‐based combination chemotherapy regimen.

2. An Agilent 1100 Series LC‐MSD system (Agilent Technologies, Avondale, PA, USA), with a single quadrupole mass detector using a positive atmospheric pressure chemical ionization (APCI) interface and single ion monitoring at m/z 261, was used. Chromatography was performed using a LUNA C8 5 µm 30 × 4.6 mm stainless steel column (Phenomenex, Torrance, CA, USA) and a mobile phase of aqueous acetonitrile pumped at a flow rate of 0.7 mL/min. High‐throughput solid‐phase sample extraction was performed using a Gilson ASPEC XL4 system (Gilson Medical, Middleton, WI, USA) controlled by prestored programs.

3. The standard curve for cyclophosphamide was linear over the concentration range 0.026–1.08 µg/mL (r2 > 0.994). Intra‐ and interassay accuracy and precision were 97–107 and 3–10%, respectively. The limit of detection was determined to be 0.01 µg/mL. Single ion monitoring at m/z 261 provided a high degree of specificity without interference from the matrix or other chemotherapy drugs.

4. Automated sample processing allowed the analysis of a large number of plasma samples from a clinical trial of repeated daily oral dosing of cyclophosphamide. One hour after dosing, cyclophosphamide was detected in 98 of 106 plasma specimens at concentrations ranging between 0.03 and 4.88 µg/mL. Twenty‐four hours after dosing, cyclophosphamide was detected in 72 of 77 plasma specimens at concentrations ranging between 0.06 and 3.13 µg/mL. There were no time‐dependent changes in cyclophosphamide concentration during the 43 day period of repeated daily oral dosing. There was no correlation between cyclophosphamide dose and plasma concentration, despite the wide range of doses given in the clinical trial (50–125 mg/m2).

5. We conclude that a solid‐phase extraction LC‐MS technique was validated for determining cyclophosphamide in human plasma. Interoccasion variability in the rate of oral absorption and in the clearance of systemically available drug may have contributed to the wide range of cyclophosphamide concentrations found at 1 and 24 h after tablet ingestion.
Effects of antidigoxin antiserum on endoxin levels, apoptosis and the expression of Bax and Bcl‐2 protein in ischaemia–reperfusion myocardium
Authors: Ke Yong‐Sheng , Liu Zhao‐Fang , Wang De‐Guo , Wang He‐Gui
Published: November 2004

1. The aim of the present study was to investigate the effects of antidigoxin antiserum (ADA), an endoxin special antagonist, on endoxin levels, apoptosis and the expression of the apoptosis‐related protein bcl‐2 and bax in myocardial ischaemia–reperfusion (MIR).

2. The left anterior descending coronary artery was subjected to 30 min ischaemia followed by 45 min reperfusion in open‐chest anaesthetized rats. The rats were divided randomly into seven groups: a sham‐operated group, an MIR group, a vehicle control (normal saline) group, and groups receiving verapamil (5 mg/kg) or ADA (9, 18 and 36 mg/kg). The drugs were injected into rats via the femoral vein before reperfusion was commenced.

3. Myocardial endoxin levels were measured by radioimmunoassay. Apoptotic cells was detected using the terminal deoxyribonucleotidyl transferase‐mediated dUTP–digoxigenin nick end‐labeling method. The expression of the apoptosis‐related proteins bcl‐2 and bax was detected by immunohistochemistry and their semiquantification scores were recorded by a computer image analysis system.

4. Myocardial endoxin levels, the number of apoptotic cells and bax protein expression were increased in the MIR group compared with the sham group.

5. Although bcl‐2 protein expression was elevated in the MIR group, there was no significant difference between the MIR and sham groups. However, the ratio of bcl‐2/bax was significantly decreased in the MIR group.

6. In the group receiving 36 mg/kg ADA, myocardial endoxin levels, the number of apoptotic cells and bax protein expression were significantly decreased; bcl‐2 protein expression was enhanced. The bcl‐2/bax ratio was increased.

7. The results suggest that ADA inhibited myocardial apoptosis induced by MIR in rats. The mechanisms involved require further investigation, but the present study may suggest that ADA prevents bax upregulation and enhances bcl‐2 upregulation by antagonizing the effects of endoxin.
Mechanism of ouabain‐induced contractions in guinea‐pig tracheal rings
Authors: Espinosa‐Tanguma R , Valle‐Aguilera JR , Zarazúa‐Garcia O , Navarro‐Huerta MP , Pecina C , Sánchez‐Armass S
Published: November 2004

1. The aim of the present study was to analyse the mechanism that underlies the force development induced by ouabain (ED100 = 100 µmol/L) in guinea‐pig tracheal rings.

2. The dose–response curve showed that concentrations of ouabain above 100 µmol/L evoked smaller contractions.

3. Ouabain, at 100 µmol/L, produced two long‐lasting consecutive transient contractions. The peak of the first contraction was 750 ± 75 mg, whereas the peak of the second contraction was 280 ± 46 mg.

4. Both contractions induced by ouabain were dependent on extracellular Ca2+. Consistent with this, verapamil (10 µmol/L) inhibited the first and second contractions by 77 and 59%, respectively.

5. 3,4‐Dichlorobenzamil (20 µmol/L) inhibited the first and second contractions by 68 and 97%, respectively.

6. Simultaneous exposure to 15 mmol/L sodium solution and 100 µmol/L ouabain evoked only one transient contraction, larger (987 ± 135 mg) than either of the ouabain‐induced contractions.

7. Inhibition of the sarcoendoplasmic reticulum Ca‐ATPase with cyclopiazonic acid potentiated the first and second ouabain‐induced contractions by 47 and 300%, respectively.

8. Atropine (1 µmol/L) inhibited the first and second contractions by 44 and 76%, respectively.

9. In conclusion, the results of the present study are relevant to the understanding of the mechanisms by which ouabain (100 µmol/L) contracts guinea‐pig tracheal rings. At the muscular level, oubain induces Ca2+ influx through L‐type Ca2+ channels and the reverse mode of the sodium–calcium exchanger. At the nerve terminals, ouabain promotes the release of acetylcholine secondary to the increase in Ca2+ influx mediated by the reverse mode of the sodium–calcium exchanger.
Oscillatory transient inward currents in ventricular myocytes of healthy versus myopathic Syrian hamster
Authors: Wu Sze‐Hsueh , Chen Yao‐Chang , Higa Satoshi , Lin Cheng‐I
Published: November 2004

1. The present experiments were performed in order to study abnormal action potential configuration and ion channel activity in ventricular myocytes obtained from 23 male myopathic Syrian hamsters (Biobreeders strain 14.6, 32–52 weeks old) compared with 10 age‐matched healthy control hamsters (Biobreeders F1B) by means of whole‐cell patch‐clamp techniques.

2. The results show that the myopathic myocytes had a longer action potential duration, a reduced transient outward K+ current on depolarization and a smaller transient inward current on repolarization after prolonged depolarizing pulses (> 500 msec). However, the L‐type Ca2+ current and the inwardly rectifing K+ current were not significantly different from those of healthy myocytes.

3. The oscillatory transient inward currents could be diminished by treatment with ryanodine (0.01–1 µmol/L), a sarcoplasmic reticulum (SR) Ca2+ release channel blocker, or with Na+‐free superfusate.

4. We conclude that the hereditary myopathic hamsters are less likely to develop delayed afterdepolarization‐related transient inward currents and triggered arrhythmias owing to a smaller SR Ca2+ content.
Influence of form IA RubisCO and environmental dissolved inorganic carbon on the δ13C of the clam‐chemoautotroph symbiosis Solemya velum
Authors: Scott Kathleen M. , Schwedock Julie , Schrag Daniel P. , Cavanaugh Colleen M.
Published: November 2004

Many nutritive symbioses between chemoautotrophic bacteria and invertebrates, such as Solemya velum, have δ13C values of ∼ −30 to − 35‰, considerably more depleted than phytoplankton. Most of the chemoautotrophic symbionts fix carbon with a form IA ribulose 1,5‐bisphosphate carboxylase (RubisCO). We hypothesized that this form of RubisCO discriminates against 13CO2 to a greater extent than other forms. Solemya velum symbiont RubisCO was cloned and expressed in Escherichia coli, purified and characterized. Enzyme from this recombinant system fixed carbon most rapidly at pH 7.5 and 20–25°C. Surprisingly, this RubisCO had an ɛ‐value (proportional to the degree to which the enzyme discriminates against 13CO2) of 24.4‰, similar to form IB RubisCOs, and higher than form II RubisCOs. Samples of interstitial water from S. velum's habitat were collected to determine whether the dissolved inorganic carbon (DIC) could contribute to the negative δ13C values. Solemya velum habitat DIC was present at high concentrations (up to ∼5 mM) and isotopically depleted, with δ13C values as low as ∼− 6‰. Thus environmental DIC, coupled with a high degree of isotopic fractionation by symbiont RubisCO likely contribute to the isotopically depleted δ13C values of S. velum biomass, highlighting the necessity of considering factors at all levels (from environmental to enzymatic) in interpreting stable isotope ratios.
Isolation and cultivation of Walsby's square archaeon
Authors: Bolhuis Henk , Poele Evelien M. te , Rodriguez‐Valera Francisco
Published: November 2004

In 1980, A. E. Walsby described a square halophilic archaeon. This archaeon is of specific interest because of its unique shape and its abundance in hypersaline ecosystems, which suggests an important ecophysiological role. Ever since its discovery, the isolation and cultivation of ‘Walsby's square archaeon’ has been a holy grail for many microbiologists working on halophiles. Despite their abundance and easy recognition by microscopy, all cultivation attempts have failed up to now, marking the organism as one of the unculturables. Cultivation of the square archaeon is essential to understand their ecophysiological role and the nature of their unique morphologically features. Here, we report the isolation and cultivation of the enigmatic square archaeon that we propose to name Haloquadratum walsbyi. Pure cultures are easily maintained in simple artificial hypersaline media. Initial growth experiments revealed a tolerance to high concentrations of MgCl2 (>2 M) in the presence of 3.3 M NaCl. Fresh cultures contained extraordinary large cells (>40 × 40 µm) without any visible division structures, ranking them among the largest prokaryotes known to date. The genome was estimated to contain approximately three million basepairs.
Insights into the genomic basis of niche specificity of Pseudomonas putida KT2440
Authors: Dos Santos V. A. P. Martins , Heim S. , Moore E. R. B. , Strätz M. , Timmis K. N.
Published: November 2004

A major challenge in microbiology is the elucidation of the genetic and ecophysiological basis of habitat specificity of microbes. Pseudomonas putida is a paradigm of a ubiquitous metabolically versatile soil bacterium. Strain KT2440, a safety strain that has become a laboratory workhorse worldwide, has been recently sequenced and its genome annotated. By drawing on both published information and on original in silico analysis of its genome, we address here the question of what genomic features of KT2440 could explain or are consistent with its ubiquity, metabolic versatility and adaptability. The genome of KT2440 exhibits combinations of features characteristic of terrestrial, rhizosphere and aquatic bacteria, which thrive in either copiotrophic or oligotrophic habitats, and suggests that P. putida has evolved and acquired functions that equip it to thrive in diverse, often inhospitable environments, either free‐living, or in close association with plants. The high diversity of protein families encoded by its genome, the large number and variety of small aralogous families, insertion elements, repetitive extragenic palindromic sequences, as well as the mosaic structure of the genome (with many regions of ‘atypical’ composition) and the multiplicity of mobile elements, reflect a high functional diversity in P. putida and are indicative of its evolutionary trajectory and adaptation to the diverse habitats in which it thrives. The unusual wealth of determinants for high affinity nutrient acquisition systems, mono‐ and di‐oxygenases, oxido‐reductases, ferredoxins and cytochromes, dehydrogenases, sulfur metabolism proteins, for efflux pumps and glutathione‐S‐transfereases, and for the extensive array of extracytoplasmatic function sigma factors, regulators, and stress response systems, constitute the genomic basis for the exceptional nutritional versatility and opportunism of P. putida , its ubiquity in diverse soil, rhizosphere and aquatic systems, and its renowned tolerance of natural and anthropogenic stresses. This metabolic diversity is also the basis of the impressive evolutionary potential of KT2440, and its utility for the experimental design of novel pathways for the catabolism of organic, particularly aromatic, pollutants, and its potential for bioremediation of soils contaminated with such compounds as well as for its application in the production of high‐added value compounds.
The effects of topical application of phytonadione, retinol and vitamins C and E on infraorbital dark circles and wrinkles of the lower eyelids
Authors: Mitsuishi T , Shimoda T , Mitsui Y , Kuriyama Y , Kawana S
Published: November 2004

Background  Infraorbital dark circles and wrinkles of the lower eyelids are a cosmetic problem, especially with age.

Aims  To determine whether a gel containing 2% phytonadione, 0.1% retinol and 0.1% vitamins C and E is effective in reducing dark under‐eye circles and wrinkles of the lower eyelids in healthy Japanese adults.

Patients/Methods  Fifty‐seven adult Japanese volunteers with dark under‐eye circles and wrinkles were enrolled in an open label study. The gel formulation was applied twice daily to the lower eyelid site for 8 weeks. Haemostasis, pigmentation and wrinkles were evaluated by a physician and by the patients themselves, using a digital camera and a visual analogue scale respectively, after 4 and 8 weeks of treatment.

Results  Topical application of the gel decreased not only haemostasis but also wrinkles after 8 weeks of treatment. Of 57 patients, 27 (47%) had reductions in haemostasis. Wrinkles were also decreased in some patients. However, pigmentation was not clearly removed by this gel.

Conclusions  Topical application of the gel containing 2% phytonadione, 0.1% retinol, 0.1% vitamin C and 0.1% vitamin E was fairly or moderately effective in reducing dark under‐eye circles, especially in cases of haemostasis, over a short treatment period in healthy Japanese adults. This treatment also slightly decreased wrinkles.
Nicotinic acid/niacinamide and the skin
Authors: Gehring W
Published: November 2004

Nicotinic acid (also generally known as niacin) and niacinamide (also known as nicotinamide) are similarly effective as a vitamin because they can be converted into each other within the organism. The blanket term vitamin B3 is used for both.

Niacinamide is a component of important coenzymes involved in hydrogen transfer. Here, the two codehydrogenases, nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) are of central importance. Topical application of niacinamide has a stabilizing effect on epidermal barrier function, seen as a reduction in transepidermal water loss and an improvement in the moisture content of the horny layer. Niacinamide leads to an increase in protein synthesis (e.g. keratin), has a stimulating effect on ceramide synthesis, speeds up the differentiation of keratinocytes, and raises intracellular NADP levels. In ageing skin, topical application of niacinamide improves the surface structure, smoothes out wrinkles and inhibits photocarcinogenesis. It is possible to demonstrate anti‐inflammatory effects in acne, rosacea and nitrogen mustard‐induced irritation.

Because of its verifiable beneficial effects, niacinamide would be a suitable component in cosmetic products for use in disorders of epidermal barrier function, for ageing skin, for improving pigmentary disorders and for use on skin prone to acne.
Patterns of neotenic differentiation in a subterranean termite,Reticulitermes speratus(Isoptera: Rhinotermitidae)
Authors: MIYATA Hitoshi , FURUICHI Hiroko , KITADE Osamu
Published: November 2004

Plasticity in the caste developmental pathway is a remarkable characteristic of termite societies. InReticulitermes, two types of neotenic reproductive, nymphoids and ergatoids, may differentiate from nymphs and workers and take over reproduction in the colony after the death of the original primary reproductive pair. We examined the dynamics of newly differentiated nymphoids and ergatoids in experimentally orphaned laboratory colonies ofR. speratuswith different caste compositions. The period required for differentiation of nymphoids was shorter than that for differentiation of ergatoids. The sex ratio of neotenics was strongly female‐biased, particularly in ergatoids. The results suggested that the number of differentiated ergatoids was restricted by the existence of nymphs or nymphoids in a colony. Workers were assumed to kill most newly differentiated neotenics. Attack reflecting conflict between colony members is probably an important mechanism to control neotenic emergence.
Does the age of the host plant modulate migratory activity ofPlutella xylostella?
Authors: CAMPOS Wellington G. , SCHOEREDER José H. , SPERBER Carlos F.
Published: November 2004

Ephemeral plants and most tropical crops are available to herbivore insects as irregular and unpredictable patches of resources. Insects that exploit patched habitats usually have well‐developed migratory ability, and migration is a fundamental process in the cycle of colonization and extinction of the local populations. We ask here whetherPlutella xylostella(Lepidoptera: Yponomeutidae) uses the aging process of the host plant to modulate its migratory activity. The insect was reared in the laboratory on the leaves from the middle estratum (fourth expanded leaves) of cabbage (Brassica oleraceaevar.capitata) of various ages, and on leaves from three strata of the mature plant. Females that spent their larval phase in young and tender plants lived for a shorter period of time and laid eggs immediately after metamorphosis. In contrast, mature plants, particularly the new leaves from the superior stratum, favored the development of adult phenotypic traits that occur in migratory forms, such as reduced body size, increased longevity and delayed reproductive activity. We suggest that the lesser nutritional quality and the short temporal persistence of mature plants are selective forces favoring individuals that are better prepared to abandon their habitat soon after emergence.Plutella xylostellamay use the predictable ontogenetic changes of the ephemeral host plant to modulate its physiological and behavioral migratory ability.
Fungus gnats of the genus Urytalpa Edwards (Diptera: Keroplatidae) in Japan
Authors: UESUGI Kenta
Published: November 2004

Three Japanese species of the genus Urytalpa are examined. Urytalpa sapporoensis (Okada) is transferred from Zelmira. Urytalpa yoshidai and U. crassicauda are described as new to science. Morphological characters indicate that U. yoshidai is closely related to Asindulum montanum Röder, and the genus Urytalpa is indicated to be non‐monophyletic. A key to the Japanese species is given.
Secondary host generation of the gall aphid Cerataphis jamuritsu (Homoptera)
Authors: KUROSU Utako , AOKI Shigeyuki , WANG Chuan‐Chan , LEE How‐Jing
Published: November 2004

Colonies of a Cerataphis species with well‐developed horns were found on the rattan Calamus quinquesstinervis in southern Taiwan. The morphology of first instar nymphs from the colonies accorded well with the morphology of first instar nymphs laid by alates of Cerataphis jamuritsu from galls on Styrax suberifolia, indicating that the rattan aphids are the secondary host generation of C. jamuritsu. Although the aphid colonies were attended by ants, the sharp horns of the first instar nymphs suggest that they might attack predators.
Phylogeography of the leaf beetle Chrysolina virgata in wetlands of Japan inferred from the distribution of mitochondrial haplotypes
Authors: SOTA Teiji , HAYASHI Masakazu , IWAI Daisuke
Published: November 2004

The genetic differentiation among populations of the leaf beetle Chrysolina virgata living in wetlands of Japan was studied based on the sequence data of the mitochondrial cytochrome oxidase subunit I gene region (750 bp). Two distinct lineages of mitochondrial haplotypes were found: one (clade A) consisted of 26 haplotypes distributed over the distribution range of C. virgata between north‐east Honshu and Kyushu, whereas the other (clade B) was monotypic and confined to a small region in north‐east Honshu where it coexisted with clade A. Nested clade analysis for these haplotypes suggested that range expansion and following differentiation due to isolation by distance might have resulted in the present distribution pattern of the haplotypes in clade A. We discuss the evolutionary process leading to the occurrence of two distinct haplotype clades in Japan in terms of repeated colonization from the continent and range expansion and contraction during climatic changes.
Descriptions of two new and one little known species of the genus Cacopsylla (Hemiptera: Psyllidae) on Sorbus japonica (Rosaceae) and an observation of their biology
Authors: INOUE Hiromitsu
Published: November 2004

Three species of the genus Cacopsylla were collected from Sorbus japonica in Japan. Two of them, Cacopsylla elegans and Cacopsylla sorbicoccinea, are described as new species based on adults and fifth (final) nymphal instars. The third species, Cacopsylla midoriae, is newly transferred from the genus Psylla. The adult of C. midoriae is redescribed and the nymph is described for the first time. A key to the species feeding on S. japonica (adults and nymphs) is provided. The three species were observed to coexist on the same tree of S. japonica in northern Kyushu. Such coexistence of psylloid congeners is uncommon in Japan.
Application of a Pressure‐relieving Air Compliance Chamber in a Single‐pulsatile Extracorporeal Life Support System: An Experimental Study
Authors: Kim Tae Sik , Sun Kyung , Lee Kyu Baek , Lee Hye Won , Baek Kwang Je , Park Sung Young , Son Ho Sung , Kim Kwang Taik , Kim Hyoung Mook
Published: November 2004

Abstract:  Nonpulsatile blood pumps are mainly used in extracorporeal life support systems. Although pulsating blood flow is known to be physiological, a pulsatile pump is not commonly applied in a circuit with a membrane oxygenator because of damage to the blood cells. The hypothesis that the placement of a pressure‐relieving compliance chamber in a circuit might reduce blood cell trauma was tested. An extracorporeal life support circuit was constructed in an acute lung injury model of dogs by oleic acid infusion. The animals were divided into three groups. In group I (n = 6) a nonpulsatile centrifugal pump was used as a control. In group II (n = 4) a single‐pulsatile pump was used, and in group III (n = 6) a single‐pulsatile pump equipped with a compliance chamber was used. Pump flow was maintained at 1.8–2.0 L/min for 2 h. Hemodynamics and blood gas analyses indicated that the pulsatile groups II and III had better results than the nonpulsatile group I. The plasma‐free hemoglobin level, which indicates blood cell trauma, was the lowest in group I and the highest in group II but was significantly decreased in group III. A pressure‐relieving compliance chamber could significantly reduce  high  circuit pressures and blood cell trauma.
Experimental Determination of Dynamic Characteristics of the VentrAssist Implantable Rotary Blood Pump
Authors: Chung Michael K.H. , Zhang Nong , Tansley Geoff D. , Qian Yi
Published: November 2004

Abstract:  The VentrAssist implantable rotary blood pump, intended for long‐term ventricular assist, is under development and is currently being tested for its rotor‐dynamic stability. The pump consists of a shaftless impeller, which also acts as the rotor of the brushless DC motor. The impeller remains passively suspended in the pump cavity by hydrodynamic forces, which result from the small clearances between the outside surfaces of the impeller and the pump cavity. These small clearances range from approximately 50 µm to 230 µm in size in the version of pump reported here. This article presents experimental investigation into the dynamic characteristics of the impeller‐bearing‐pump housing system of the rotary blood pump for increasing pump speeds at different flow rates. The pump was mounted on a suspension system consisting of a platform and springs, where the natural frequency and damping ratio for the suspension system were determined. Real‐time measurements of the impeller's displacement were performed using Hall effect sensors. A vertical disturbance force was exerted onto the pump housing, causing the impeller to be displaced in vertical direction from its dynamic equilibrium position within the pump cavity. The impeller displacement was represented by a decaying sine wave, which indicated the impeller restoring to its equilibrium position. From the decaying sine wave the natural frequency and stiffness coefficient of the system were determined. Furthermore, the logarithmic decrement method was used to determine the damping ratio and eventually the damping coefficient of the system. Results indicate that stiffness and damping coefficients increased as flow rate and pump speed increased, representing an increase in stability with these changing conditions. However, pump speed had a greater influence on the stiffness and damping coefficients than flow rate did, which was evident through dynamic analysis. Overall the experimental method presented in this article was successful in determining the dynamic characteristics of the system.
A Minor Experimental Stenosis in Porcine Descending Thoracic Aorta Affects the Spectral Content of Pressure Pulse Wave
Authors: Tsatsaris Athanasios , Iliopoulos Dimitrios , Baldoukas Antonios , Berketis Nikolaos , Triantafyllou Ioannis , Triantafyllou Dimitrios
Published: November 2004

Abstract:  Objective: To carry out research into the possible changes of the spectral content of pressure pulse wave after the creation of an experimentally induced stenosis in the pig descending thoracic aorta. Methods: Eight healthy, normotensive Landrace pigs were subjected to thoracotomy under sterile conditions. At the upper segment of the descending thoracic aorta, a 5‐mm‐long circumferential symmetric constriction was imposed and stabilized; hence, a 15–20 mm Hg pressure gradient was established. Pressure tip catheters were used in order to monitor the pressure gradient. Blood flow disturbances were recorded through a bidirectional Doppler flow meter at pre‐ and poststenotic areas (A and B, respectively). Measurements were carried out before, 10 min after, and 90 days after the creation of the stenosis. The recorded waveforms were analyzed mathematically by using Fourier Transform, in order to determine their spectral component. Eight sham‐operated pigs were used as controls. Results: Fourier Transform analysis showed a significant increase (P < 0.05) of spectral content in A and B areas. Also, the “relative” harmonic amplitudes in nonstenotic subjects were higher than in stenotic animals (P < 0.05). Conclusions: A minor experimental constriction located at the level of the descending thoracic aorta increased the spectral content of the pressure pulse wave, indicating that spectral analysis may detect slight flow disturbances before developing remarkable signs of an impaired circulation system.
A methodology using subjective and objective measures to compare plaque inhibition by toothpastes
Authors: Claydon N. , Yates R. , Labello R. , Hall C. , Armstrong R. , Addy M.
Published: November 2004

Objectives: Plaque scoring usually employs subjective indices. The aim was to compare plaque inhibition of three toothpastes using two objective and one subjective measures of plaque.

Material and Methods: Formulations were: (1) an experimental anti‐plaque paste (test); (2) an experimental paste (minus active or negative control); and (3) a proprietary anti‐plaque toothpaste product (positive control). The study was a blind, randomised crossover design using a 4‐day, no tooth brushing, plaque regrowth model and involving 22 healthy subjects. After baseline plaque removal, subjects rinsed twice a day with slurries of the allocated paste. On day 5, plaque was scored by index, wet weight and optical density of extracted disclosing solution from the plaque (stain intensity).

Results: All data showed the same pattern. There were highly significant subject and treatment effects but not period effects. The positive control was highly significantly more effective in plaque control than the test and minus active experimental formulations, which in turn were not significantly different from each other. There were strong and significant correlations between pairs of scoring methods particularly wet weight and stain intensity.

Conclusion: The use of objective methods of plaque alongside conventional subjective indices provided convincing evidence for increased discriminatory power in a study comparing plaque inhibition by toothpastes.
Clinical study to compare the effectiveness of a test whitening toothpaste with a commercial whitening toothpaste at inhibiting dental stain
Authors: Claydon N. C. A. , Moran J. , Bosma M. L. , Shirodaria S. , Addy M. , Newcombe R.
Published: November 2004

Aims: A single centre, randomised single‐blind, three‐way crossover study was performed, to compare the effect of an experimental test toothpaste with a commercially available whitening toothpaste and water control at inhibiting extrinsic stain promoted by repeated chlorhexidine/tea rinses.

Methods: This study used 23 subjects. During the week before the study the subjects received a prophylaxis to remove all staining, plaque and calculus deposits. On the Monday of the following week subjects returned to the clinic to receive their rinses and to check their dentition was stain free. Under direct supervision at both 09:00 and 13:00 hours they rinsed with either a toothpaste slurry or water control that was repeated daily up to and including the following Thursday. Additionally from the Monday to the Thursday each subject rinsed with a 0.2% chlorhexidine mouthrinse, immediately followed by a rinse with a warm black tea solution. This cycle was repeated hourly eight times throughout the day and on the following days until the Friday. Throughout this period volunteers omitted all other forms of oral hygiene except rinsing with the chlorhexidine mouthwash. On the Friday the level of stain on the teeth and dorsum of tongue was assessed using the Lobene stain index for both stain area and intensity. At the end of each trial period each subject received a thorough prophylaxis to remove all plaque, calculus and staining before starting the second and third period of the study.

Results: As expected appreciable amounts of extrinsic stain accumulated on the teeth over each study period. The amount of stain following use of the toothpastes and water control was least with the experimental toothpaste, followed by water control and lastly the commercial whitening paste. For all sites combined there was evidence that the experimental paste was significantly superior to both the commercial paste and water control at reducing stain area (p<0.001), a product of stain area and intensity (p<0.001 and 0.05, respectively) but not stain intensity (p>0.05).

Conclusions: In this stain‐prevention model the use of an experimental paste showed a significant reduction in stain accumulation on the teeth compared with a (placebo) negative water control and a commercially available whitening paste. As such the experimental paste would be expected to be of benefit in controlling extrinsic dental staining.
The effectiveness of a toothpaste containing Triclosan and polyvinyl‐methyl ether maleic acid copolymer in improving plaque control and gingival health
Authors: Davies R. M. , Ellwood R. P. , Davies G. M.
Published: November 2004

Objective: To compare the effectiveness of triclosan/copolymer and fluoride dentifrices in improving plaque control and gingival health.

Search strategy: We searched the Cochrane Controlled Trials Register, MEDLINE (1986 to March 2003) and EMBASE (1986 to March 2003). Personal files and the reference lists of all articles were checked for further studies.

Selection criteria: Trials were selected if they met the following criteria: random allocation of participants; participants were adults with plaque and gingivitis; unsupervised use of dentifrices for at least 6 months; and primary outcomes – plaque and gingivitis after 6 months.

Data collection and analysis: Two reviewers independently extracted information. For each plaque and gingivitis index, the mean differences for each study were pooled as weighted mean differences (WMDs) with the appropriate 95% confidence intervals (CIs) using the random effect models.

Main results: Sixteen trials provided data for the meta‐analysis. The triclosan/copolymer dentifrice significantly improved plaque control compared with a fluoride dentifrice, with a WMD of −0.48 (95% CI: −0.64 to −0.32) for the Quigley–Hein index and WMD of −0.15 (95% CI: −0.20 to −0.09) for the plaque severity index. When compared with a fluoride dentifrice, the triclosan/copolymer dentifrice significantly reduced gingivitis with WMDs −0.26 (95% CI: −0.34 to −0.18) and −0.12 (95% CI: −0.17 to −0.08) for the Loe and Silness index and gingivitis severity index, respectively.