bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural, electrical transport, magnetization, and 1∕f noise studies in 200MeV Ag ion irradiated La0.7Ce0.3MnO3 thin films
Authors: Kumar Ravi , Choudhary R. J. , Patil S. I. , Husain Shahid , Srivastava J. P. , Sanyal S. P. , Lofland S. E.
Published: December 2004

The effect of 200MeV Ag ion irradiation on structural, electrical transport, magnetization, and low-frequency conduction noise properties of electron-doped La0.7Ce0.3MnO3 thin films have been investigated. The as-grown thin films show c-axis epitaxial structure along with a small amount of unreacted CeO2 phase. After the irradiation, at the lowest fluence both the magnetization and metal-insulator transition temperature increase. Further increase in fluence reduces the metal-insulator transition temperature and leads to larger resistivity; however, the unreacted phase of CeO2 disappears in the x-ray diffraction pattern. On the other hand, the normalized electrical noise is greatly enhanced even at the lowest nonzero fluence. Surprisingly the conducting noise in the irradiated samples is much higher in the metallic state than in the semiconducting one. The observed modifications in structural, electrical, magnetic, and noise properties of 200MeV Ag ion irradiated La0.7Ce0.3MnO3 thin films have been explained on the basis of effects of the presence of swift heavy-ion irradiation-induced strain and defects.
Conductivity of a two-dimensional electron gas in magnetic field in the presence of microwave radiation
Authors: Lyapilin I. I. , Patrakov A. E.
Published: December 2004

The experimental observations of novel behavior of the kinetic properties of a two-dimensional electron gas in the presence of microwave radiation are reviewed, and the various theoretical models that have been proposed for explaining them are described.
Formation of a self-consistent double quantum well in a wide p-type quantum well
Authors: Alshanskiı̆ G. A. , Yakunin M. V.
Published: December 2004

The process of formation of self-consistent double quantum wells (DQWs) in a wide p-type quantum well in the presence of uniaxial strain is investigated. A feature of p-type systems is the structure of the valence band, which consists of two branches of energy dispersion—light and heavy holes. It is shown that this feature leads to significant splitting of the subbands of symmetric and antisymmetric states, as a result of which it is difficult to form states of the DQW with a vanishingly small tunneling gap; a uniaxial strain, by lifting the degeneracy of the band, suppresses this property, so that the two ground subbands of the size quantization of the DQW remain degenerate to high energies.
Oscillations of the conductivity of a two-dimensional electron gas in the presence of microwave radiation
Authors: Patrakov A. E. , Lyapilin I. I.
Published: December 2004

The conductivity of two-dimensional electrons under microwave irradiation at magnetic fields in the region where the usual Shubnikov–de Haas oscillations do not appear is investigated in the framework of the Boltzmann transport equation. It is shown that under such conditions the microwave radiation gives rise to a new type of oscillations of the components of the conductivity tensor.
Dynamics of the insulator–conductor transition initiated by high pressure in ammonium halides
Authors: Tikhomirova G. V. , Babushkin A. N.
Published: December 2004

A comparative study is made of the influence of high pressures (15–50 GPa) on the conductance of the ammonium halides NH4X (X=F, Cl, Br) at temperatures of 77 K and above. It is found that the application of high pressure induces a phase transition which is manifested in a sharp (jumplike) change in the resistance by several (more than three) orders of magnitude and is accompanied by hysteresis typical of a first-order phase transition. The values of the pressure Pc1 correlate with the density of the material and are approximately 40, 27, and 15 GPa for NH4F, NH4Cl, and NH4Br, respectively. The relaxation times of the resistance depend strongly on the pressure: in the transition region the relaxation time is increased significantly (from several hours to days). At pressures much higher than Pc1 it is several minutes.
Multiple paternity in field- and captive-laid egg strands of Sepioteuthis australis (Cephalopoda:Loliginidae)
Authors: van Camp L. M. , Donnellan S. C. , Dyer A. R. , Fairweather P. G.
Published: December 2004

Previous observations on the mating behaviour of the southern calamary, Sepioteuthis australis Quoy & Gaimard 1833, revealed the potential for multiple paternities within egg strands, which contained up to eight eggs each. Six egg masses were laid in captivity from a possible 14 female and 20 male parents. By using five microsatellite loci, 112 eggs from 35 randomly selected egg strands were assigned sires using the potential fathers’ genotypes. Seven egg strands containing 22 eggs were also collected from the field to test that squid in captivity were apportioning eggs in natural ways, and that multiple paternity within egg strands was not an artefact of captivity. Ninety-seven per cent of strands laid in captivity showed multiple paternities. Similarly, multiple fathers were also evident in the field-laid egg strands. The maximum number of sires found within a single egg strand was four; however, three sires were more common. This is the first account of multiple paternities within egg strands laid by Sepioteuthis. It is likely that females are ‘spermatophore-limited’ when egg laying, and are promiscuous to ensure a ready supply of these sperm packets. Moreover, genetic diversity in a brood is increased by this mating strategy.
Does the quantity and timing of fresh water flowing into a dry tropical estuary affect year-class strength of barramundi (Lates calcarifer)?
Authors: Staunton-Smith Jonathan , Robins Julie B. , Mayer David G. , Sellin Michelle J. , Halliday Ian A.
Published: December 2004

The influence of fresh water flowing into estuaries on biological processes, such as recruitment of juvenile fish, is poorly understood, but important if freshwater resources are to be managed sustainably. Typically, lagged correlations between freshwater flows and fisheries production (i.e. catch) are used to support speculation that flows affect the survival of fish (and thus year-class strength) during their first year of life. The present study compares the relative strength of year classes in an estuarine fish population with two indices of fresh water flowing into the estuary, river flow and coastal rainfall. Year-class strength was estimated from a subset of the age structure of commercially caught adult barramundi (Lates calcarifer), which were sampled at seafood processors for three consecutive years. Strong and coherent fluctuations in year-class strength were observed. Positive correlations were found between the abundance of year classes (accounting for age) and quantity of fresh water flowing into the estuary during spring and summer, when barramundi spawn and young-of-the-year recruit to nursery habitats. Regression analysis was used to explore the relationships between year-class strength and environmental variables. A possible, but unproven, causal mechanism for the relationship is that the quantity of fresh water flowing into the estuary during spring and summer influences the survival of early life-history stages of barramundi (i.e. juvenile recruitment) by altering accessibility, productivity and or carrying capacity of nursery habitats.
pH effects on the stability and dimerization of procaspase‐3
Authors: Bose Kakoli , Clark A. Clay
Published: December 2004

pH‐dependent conformational changes are known to occur in dimeric procaspase‐3, and they have been shown to affect the rate of automaturation. We studied the equilibrium unfolding of procaspase‐3(C163S) as a function of pH (between pH 8.5 and pH 4) in order to examine these changes in the context of folding and stability. The data show that the procaspase dimer undergoes a pH‐dependent dissociation below pH 5, so that the protein is mostly monomeric at pH 4. Consistent with this, the dimer unfolds via a four‐state process between pH 8.5 and pH 4.75, in which the native dimer isomerizes to a dimeric intermediate, and the dimeric intermediate dissociates to a monomer, which then unfolds. In contrast, a small protein concentration dependence was observed by circular dichroism, but not by fluorescence emission, at pH 4.5 and pH 4.2. There was no protein‐concentration dependence to the data collected at pH 4. Overall, the results are consistent with the redistribution of the population of native dimer (N2) to dimeric intermediate (I2) to monomeric intermediate (I), as the pH is lowered so that at pH 4, the “native” ensemble resembles the monomeric intermediate (I) observed during unfolding at higher pH. An emerging picture of the monomeric procaspase is discussed. Procaspase‐3 is most stable at pH ∼7 (24–26 kcal/mol), and while the stability decreased with pH, it was observed that dimerization contributes the majority (>70%) of the conformational free energy.
Modifications of human βA1/βA3‐crystallins include S‐methylation, glutathiolation, and truncation
Authors: Lapko Veniamin N. , Cerny Ronald L. , Smith David L. , Smith Jean B.
Published: December 2004

Disulfide bonding of lens crystallins contributes to the aggregation and insolubilization of these proteins that leads to cataract. A high concentration of reduced glutathione is believed to be key in preventing oxidation of crystallin sulfhydryls to form disulfide bonds. This protective role is decreased in aged lenses because of lower glutathione levels, especially in the nucleus. We recently found that human γ‐crystallins undergo S‐methylation at exposed cysteine residues, a reaction that may prevent disulfide bonding. We report here that βA1/A3‐crystallins are also methylated at specific cysteine residues and are the most heavily methylated of the human lens crystallins. Among the methylated sites, Cys 64, Cys 99, and Cys 167 of βA1‐crystallin, methylation at Cys 99 is highest. Cys 64 and Cys 99 are also glutathiolated, even in a newborn lens. These post‐translational modifications of the exposed cysteines may be important for maintaining the crystallin structure required for lens transparency. Previously unreported N‐terminal truncations were also found.
Structure of rhodocetin reveals noncovalently bound heterodimer interface
Authors: Paaventhan Palasingam , Kong Chunguang , Joseph Jeremiah S. , Chung Max C.M. , Kolatkar Prasanna R.
Published: December 2004

Rhodocetin is a unique heterodimer consisting of α‐ and β‐subunits of 133 and 129 residues, respectively. The molecule, purified from the crude venom of the Malayan pit viper, Calloselasma rhodostoma, functions as an inhibitor of collagen‐induced aggregation. Rhodocetin has been shown to have activity only when present as a dimer. The dimer is formed without an intersubunit disulfide bridge, unlike all the other Ca2+‐dependent lectin‐like proteins. We report here the 1.9 Å resolution structure of rhodocetin, which reveals the compensatory interactions that occur in the absence of the disulfide bridge to preserve activity.
Orthogonal site‐specific protein modification by engineering reversible thiol protection mechanisms
Authors: Smith J. Jefferson , Conrad David W. , Cuneo Matthew J. , Hellinga Homme W.
Published: December 2004

Covalent modification is an important strategy for introducing new functions into proteins. As engineered proteins become more sophisticated, it is often desirable to introduce multiple, modifications involving several different functionalities in a site‐specific manner. Such orthogonal labeling schemes require independent labeling of differentially reactive nucleophilic amino acid side chains. We have developed two protein‐mediated protection schemes that permit independent labeling of multiple thiols. These schemes exploit metal coordination or disulfide bond formation to reversibly protect cysteines in a Cys2His2 zinc finger domain. We constructed a variety of N‐ and C‐terminal fusions of these domains with maltose‐binding protein, which were labeled with two or three different fluorophores. Multiple modifications were made by reacting an unprotected cysteine in MBP first, deprotecting the zinc finger, and then reacting the zinc finger cysteines. The fusion proteins were orthogonally labeled with two different fluorophores, which exhibited intramolecular fluorescene resonance energy transfer (FRET). These conjugates showed up to a threefold ratiometric change in emission intensities in response to maltose binding. We also demonstrated that the metal‐ and redox‐mediated protection methods can be combined to produce triple independent modifications, and prepared a protein labeled with three different fluorophores that exhibited a FRET relay. Finally, labeled glucose‐binding protein was covalently patterned on glass slides using thiol‐mediated immobilization chemistries. Together, these experiments demonstrated that reversible thiol protection schemes provide a rapid, straightforward method for producing multiple, site‐specific modifications.
A comparative study of the α‐subdomains of bovine and human α‐lactalbumin reveals key differences that correlate with molten globule stability
Authors: Chowdhury Farhana A. , Raleigh Daniel P.
Published: December 2004

The α‐lactalbumins form stable molten globule states under a range of conditions, with the low pH form being the best characterized. The stability of the molten globule varies among different members of this family, but the origin of the stability difference is not clear. We compare the folding and stability of α‐subdomain constructs of human and bovine α‐lactalbumin. Previous studies have demonstrated that the isolated α‐subdomain of human α‐lactalbumin folds and forms a molten globule state. The minimum core construct has been defined to include the A, B, and D α‐helices and the C‐terminal 310 helix. A construct corresponding to the same region of bovine α‐lactalbumin is much less structured and less stable than the human α‐lactalbumin construct. Addition of the C‐helix to generate a 75‐residue bovine construct does not lead to a significant increase in structure or stability. This construct (AB‐CD/310) contains the entire α‐subdomain of bovine α‐lactalbumin. Thus molten globule formation in the human protein, but not in the bovine protein, can be rationalized on the basis of a stable α‐subdomain. Interactions involving more of the protein chain are required to generate a well structured molten globule in the bovine protein. Comparison of AB‐CD/310 to the molten globule formed by the intact protein and to the protein with the 6–120 disulfide reduced indicates that both the β‐subdomain and the 6–120 disulfide play a role in stabilizing the bovine α‐lactalbumin molten globule.
Electric charge balance mechanism of extended soluble proteins
Authors: Uchikoga Nobuyuki , Takahashi Shun‐Ya , Ke Runcong , Sonoyama Masashi , Mitaku Shigeki
Published: December 2004

Extended proteins such as calmodulin and troponin C have two globular terminal domains linked by a central region that is exposed to water and often acts as a function‐regulating element. The mechanisms that stabilize the tertiary structure of extended proteins appear to differ greatly from those of globular proteins. Identifying such differences in physical properties of amino acid sequences between extended proteins and globular proteins can provide clues useful for identification of extended proteins from complete genomes including orphan sequences. In the present study, we examined the structure and amino acid sequence of extended proteins. We found that extended proteins have a large net electric charge, high charge density, and an even balance of charge between the terminal domains, indicating that electrostatic interaction is a dominant factor in stabilization of extended proteins. Additionally, the central domain exposed to water contained many amphiphilic residues. Extended proteins can be identified from these physical properties of the tertiary structure, which can be deduced from the amino acid sequence. Analysis of physical properties of amino acid sequences can provide clues to the mechanism of protein folding. Also, structural changes in extended proteins may be caused by formation of molecular complexes. Long‐range effects of electrostatic interactions also appear to play important roles in structural changes of extended proteins.
Racial Resentment and White Opposition to Race‐Conscious Programs: Principles or Prejudice?
Authors: Feldman Stanley , Huddy Leonie
Published: December 2004

White racial resentment is associated with opposition to a broad range of racial policies but it is unclear whether it derives from racial prejudice or stems from ideological principles. To resolve this ambiguity, we examined the impact of racial resentment on support for a college‐scholarship program in which program beneficiaries' race and socioeconomic class was experimentally varied. The analyses yield a potentially troubling finding: racial resentment means different things to white liberals and conservatives. Among liberals, racial resentment conveys the political effects of racial prejudice, by predicting program support for black but not white students, and is better predicted by overt measures of racial prejudice than among conservatives. Among conservatives, racial resentment appears more ideological. It is closely tied to opposition to race‐conscious programs regardless of recipient race and is only weakly tied to measures of overt prejudice. Racial resentment, therefore, is not a clear‐cut measure of racial prejudice for all Americans.
Kinetics of Glycosaminoglycan Deposition in Splenic AA Amyloidosis Induced in Mink
Authors: Wien T. N. , Sørby R. , Omtvedt L. A. , Landsverk T. , Husby G.
Published: December 2004

The kinetics of splenic glycosaminoglycan (GAG) expression in mink has been investigated during the course of AA amyloid induction, i.e. at 3 to 6 weeks of lipopolysaccharide (LPS) treatment. Splenic amyloid was demonstrated by means of Congo red staining in five of 19 LPS‐treated mink. Chondroitin/dermatan sulfate (CS/DS), as well as heparan sulfate proteoglycans (HSPG), was extracted from amyloid and control spleens. Independently of the presence of amyloid, the total amount of splenic GAGs increased with the duration of LPS treatment, and an HSPG population was found confined to the LPS‐treated spleens. The differential expression of various PG and GAG epitopes in mink spleen was investigated with the help of immunohistochemistry. The amyloid deposits were shown to contain GAG chains of CS and HS, and the core proteins of DSPG decorin and the HSPGs perlecan and agrin. Decorin and perlecan were shown in normal spleens localized to the splenic ellipsoids, an early target for AA amyloid deposition. The constitutive expression of PGs at predilection sites for amyloid deposition and their increased expression in the tissues developing amyloidosis at these early stages show that PGs are available for the formation and deposition of AA amyloid.
Activity and sequence characterization of two cysteine proteases in the digestive tract of the reduviid bug Triatoma infestans
Authors: Kollien A. H. , Waniek P. J. , Nisbet A. J. , Billingsley P. F. , Schaub G. A.
Published: December 2004

Cathepsin B‐ and cathepsin L‐like activities were identified in gut extracts of the blood‐sucking bug Triatoma infestans using specific substrates and inhibitors. Activities decreased during the first 2 days after feeding but increased to a maximum value at 5 and 10 days post feeding. The deduced 332 and 328 amino acid sequences showed high levels of identity (50–60%) to other insect cathepsin B‐ and L‐like proteases, respectively. The three amino acid residues of the catalytic domain, CHN, and the GCNGG motif were conserved in both cathepsins, but the occluding loop, characterizing B‐like cathepsins, was present only in one. ERFNIN and GNFD motifs occurred in the other sequence, defining it as cathepsin L‐like. The cathepsin B‐like gene was expressed at low, constitutive levels in unfed and fed T. infestans.
Functional roles of specific bruchid protease isoforms in adaptation to a soybean protease inhibitor
Authors: Ahn J.‐E. , Salzman R. A. , Braunagel S. C. , Koiwa H. , Zhu‐Salzman K.
Published: December 2004

Upon challenge by the soybean cysteine protease inhibitor soyacystatin N (scN), cowpea bruchids reconfigure their major digestive cysteine proteases (CmCPs) in adaptation to the inhibitor and resume normal feeding and development. We have previously shown that CmCPB transcripts were 116.3‐fold more abundant in scN‐adapted bruchid guts than in unadapted guts, while CmCPA transcripts were only 2.5‐fold higher. In order to further elucidate the functional significance of this differential regulation, we expressed three CmCPA and one CmCPB isoforms (A9, A13, A16 and B1) using a bacterial expression system, and characterized their activities. In contrast to the precursors of CmCPAs (proCmCPAs), proCmCPB1 exhibited more efficient autocatalytic conversion from the latent proenzyme to its active mature protease form, and demonstrated higher intrinsic proteolytic activity. Among proCmCPAs, dependence on exogenous enzymatic processing varies: while maturation of proCmCPA13 and proCmCPA16 was impaired in the absence of external proteolytic activity, proCmCPA9 appeared to utilize a two‐step autoprocessing mechanism. Although all CmCPs are scN‐sensitive, scN was degraded by CmCPB1 when outnumbered by the protease, but scN remained intact in the presence of excessive CmCPA9. These results provide further evidence that differential expression of CmCPs under scN challenge brings about adaptation to the inhibitor. High induction of unique cysteine protease isoforms with superior autoprocessing and proteolytic efficacy represents a strategy cowpea bruchids use to cope with dietary scN.
Relationship of nonalcoholic hepatic steatosis to overnight low‐dose dexamethasone suppression test in obese individuals
Authors: Zoppini Giacomo , Targher Giovanni , Venturi Cristina , Zamboni Cristina , Muggeo Michele
Published: December 2004

objectives  To examine the association between nonalcoholic hepatic steatosis (HS) and the activity of the hypothalamo–pituitary–adrenal (HPA) axis, as evaluated by a low‐dose dexamethasone suppression test, in obese subjects.

design and patients  In a cross‐sectional study, we examined 54 obese, otherwise healthy, individuals with a negligible or zero daily alcohol consumption.

measurements  HS (by ultrasonography), glucose tolerance status (by oral glucose load), insulin resistance [by homeostasis model assessment (HOMA)] and 1·0 mg postdexamethasone (postdex) suppression cortisol levels were measured.

results  Subjects with nonalcoholic HS (n = 39) had markedly less suppressed circulating cortisol levels than those without HS (n = 15) (21·9 ± 2·6 vs. 11·0 ± 1·4 nmol/l, P < 0·001). In addition, subjects with nonalcoholic HS had significantly higher values of HOMA‐insulin resistance score and circulating liver enzymes than their counterparts without HS. Age, body mass index (BMI), waist/hip ratio, plasma glucose concentration (both at fasting and after glucose load), lipids and blood pressure values did not differ significantly between the groups. Females were more represented among those without HS. The marked differences in postdex suppression cortisol levels that were observed between the groups were little affected by adjustment for sex, age, BMI, waist/hip ratio, HOMA‐insulin resistance score, plasma lipids and liver enzyme levels. Similarly, in a logistic regression analysis, cortisol levels significantly predicted the presence of nonalcoholic HS (P = 0·032), independently of potential confounders.

conclusions  These results suggest that nonalcoholic hepatic steatosis is closely correlated with a subtle, chronic activation of the HPA axis in obese, otherwise healthy, individuals.
Pseudo‐affective visceromotor responses and HPA axis activation following colorectal distension in rats with increased cholinergic sensitivity
Authors: Elsenbruch S. , Wang L. , Hollerbach S. , Schedlowski M. , Tougas G.
Published: December 2004

Abstract  We analysed visceromotor (VMR) and corticosterone responses to colorectal stimuli under control conditions and following acoustic stress in rats selectively bred for increased sensitivity to cholinergic agonists, the Flinders Sensitive Line (FSL) rats, compared with Flinders Resistant Line (FRL) rats. FSL rats demonstrated a significant VMR response at the smallest distension pressure, whereas no response was evident in FRL controls. FSL rats also demonstrated enhanced VMR responses at both larger distension levels compared with FRL rats. Colorectal distension (CRD) produced significant increases in serum corticosterone levels, which were comparable in FRL and FSL. Noise stress induced divergent corticosterone responses in FRL and FSL, but did not affect VMR to CRD in either group. These data suggest that FSL rats show altered VMR responses to CRD and disturbed hypothalamic–pituitary–adrenal axis responses to acute stress.
The herbal preparation STW 5 (Iberogast®) desensitizes intestinal afferents in the rat small intestine1
Authors: Liu C.‐Y. , Müller M. H. , Glatzle J. , Weiser D. , Kelber O. , Enck P. , Grundy D. , Kreis M. E.
Published: December 2004

Abstract  Introduction:  Visceral hypersensitivity in the upper gastrointestinal tract is a potential pathomechanism of functional dyspepsia. The herbal preparation STW 5 (Iberogast®) provides symptomatic relief for this condition. We aimed to investigate whether STW 5 modulates intestinal afferent sensitivity.

Methods:  The herbal preparation STW 5 or vehicle (30.8% ethanol) were administered orally in male Wister rats. After 2 h animals were anaesthetized and extracellular multi‐unit intestinal afferent nerve recordings were secured from the neurovascular bundle of the mesentery in the proximal jejunum. Afferent discharge to ramp distension of the intestinal loop (0–60 cm H2O) and dose–response curves for i.v. bradykinin (10, 20 and 40 μg kg−1) and 5‐HT (5, 10, 20 and 40 μg kg−1) were recorded.

Results:  Baseline discharge was not different between the vehicle and treatment group. Ramp distension was followed by a pressure dependent increase in afferent nerve discharge that was decreased following STW 5 pretreatment for all distending pressures reaching 147 ± 8 impulses s−1 (imp s−1) following STW 5 vs 171 ± 5 imp s−1 following vehicle at 60 cm H2O (mean ± SEM; P < 0.05). A dose‐dependent increase in afferent discharge was observed for 5‐HT and bradykinin. Following STW 5 pretreatment, afferent discharge was reduced at all doses of 5‐HT to 110 ± 5 at the maximum dose after STW 5 and 128 ± 3 imp s−1 in controls (all P < 0.05). Afferent discharge to bradykinin was similarly reduced at 20 and 40 μg kg−1 but not at 10 μg kg−1 of bradykinin with a discharge rate of 176 ± 7 imp s−1 following STW 5 and 200 ± 6 imp s−1 in controls at 40 μg kg−1 (P < 0.05).

Conclusions:  The preparation STW 5 reduces intestinal afferent nerve discharge following chemical and mechanical stimuli, while baseline discharge is not affected. This effect of STW 5 on afferent sensitivity may contribute to its therapeutic relief of dyspeptic symptoms.
Oesophageal wall stretch: the stimulus for distension induced oesophageal sensation
Authors: Takeda T. , Nabae T. , Kassab G. , Liu J. , Mittal R. K.
Published: December 2004

Abstract  Recently, we reported a novel ultrasound technique to assess the biomechanical properties of the oesophagus in humans. To investigate whether the oesophageal sensation induced by oesophageal distension correlates with wall tension, wall stress or wall strain, we studied 20 healthy subjects using a manometry catheter equipped with a high‐compliance bag and a high‐frequency intraluminal ultrasound probe. Oesophageal distensions were performed by injecting 1–20 mL water into the bag for 20–30 s. Subjects scored the nature (heartburn or chest pain) and severity of sensation in response to distension, before and after atropine (15 μg kg−1, i.v.). Ultrasound images of oesophagus were digitized and measurements were made to calculate oesophageal wall tension, stress and strain during distensions. Subjects experienced mostly heartburn, not chest pain, in response to oesophageal distension. Oesophageal wall strain and bag pressures correlated best with the oesophageal sensation. Atropine reduced bag pressure but did not affect the distension induced heartburn and chest pain. We conclude that heartburn is a common sensation in response to oesophageal distension in normal subjects. A strong correlation between wall strain and oesophageal sensation suggests that the wall stretch is the stimulus for nociceptive mechanoreceptors of the oesophagus.
Allergenic composition of the mite Suidasia medanensis and cross‐reactivity with Blomia tropicalis
Authors: Puerta L. , Lagares A. , Mercado D. , Fernández‐Caldas E. , Caraballo L.
Published: December 2004

Background:  Mites of the genus Suidasia are commonly found in house dust and may play an allergenic role in exposed populations. However, the allergenic potential and clinical impact of this genus has not been well established. The main objective of this project was to evaluate the allergenic role of the mite Suidasia medanensis.

Methods:  An extract of S. medanensis was prepared and the allergen composition determined by immunoblot. Specific IgE antibody levels to S. medanensis and Blomia tropicalis were evaluated by radioallergosorbent (RAST) in the sera of 97 allergic asthmatic patients and 50 nonallergic subjects. Cross‐reactivity between S. medanensis and the mite species B. tropicalis and Dermatophagoides farinae was investigated by RAST and immunoblot inhibitions.

Results:  Seventy‐one asthmatic patients sera (73.2%) had positive IgE reactivity to S. medanensis; 14 allergens with molecular weights ranging from 7.5 to 105 kDa were detected. The most frequently detected had molecular weights of 30–31 (54.8%), 24.5 (42%), 21 (38.7%), 47 (35%) and 58 kDa (35.5%). Blomia tropicalis extract inhibited IgE binding to nine of these identified allergens. Four B. tropicalis allergens were inhibited by S. medanensis extract. RAST inhibition results demonstrated a high degree of inhibition by B. tropicalis (87.2%) and D. farinae (90.9%) than by S. medanensis (32%).

Conclusions:  Sensitization to S. medanensis is common in asthmatic allergy patients in Cartagena. An important degree of cross‐reactivity was established between S. medanensis and B. tropicalis, and D. farinae.
Inhibition of nasal polyp mast cell and eosinophil activation by desloratadine
Authors: Kowalski M. L. , Lewandowska A. , Wozniak J. , Makowska J. , Jankowski A. , DuBuske L.
Published: December 2004

Nasal polyp tissue which contains mast cells and eosinophils is similar to the inflamed airway mucosa in cellular composition and mediator content. This investigation assessed the effect of desloratadine (DL), on activation of cells in nasal polyp tissue. Polyps were obtained from 22 patients with chronic rhinosinusitis [nine aspirin acetylosalitic acid (ASA)‐sensitive and 13 ASA‐tolerant]. Polyp tissue was dispersed by digestion, and preincubated with DL and incubated with anti‐immunoglobulin E (IgE) or calcium ionophore. LTC4, eosinophil cationic protein (ECP) and tryptase concentrations in supernatants were measured by immunoassays. Desloratadine (1, 10 and 50 μM) inhibited calcium ionophore‐induced LTC4 release by a mean of 29%, 50% and 63% respectively, and anti‐IgE‐induced LTC4 release by a mean of 27%, 35% and 39% respectively. Calcium ionophore‐induced tryptase release was inhibited 60% and 69% by 10 and 50 μM of DL, respectively, and anti‐IgE‐induced tryptase release was inhibited 33%, 47% and 66% for 1, 10 and 50 μM of DL. Desloratadine 10 μM and 50 μM inhibited ECP release by and 45% and 48% respectively. Polyp tissue from ASA‐sensitive patients when compared with ASA‐tolerant patients released at baseline significantly more ECP (medians 120.0 μg/ml, range: 69.0–182.0 vs 63.4 μg/ml, range: 3.7–172.0; P < 0.05), but similar amounts of tryptase and LTC4. This study demonstrated that DL inhibits activation of both eosinophils and mast cells derived from a site of airway mucosal inflammation.
Does atopy protect against enteric infections?
Authors: Black P. N.
Published: December 2004

Allergic sensitization to inhaled allergens and foods is common and is linked to the development of asthma, allergic rhinitis and eczema. In view of the morbidity associated with these diseases it is not clear why the genetic predisposition to atopy is so common. Children who are atopic are less likely to develop oral tolerance to ingested foods and as a result are more likely to have manifestations of food allergy including wheezing, skin rashes and gastrointestinal symptoms. Oral tolerance also develops to micro‐organisms in the gastrointestinal tract. Children who are atopic may be protected against enteric infections in early childhood because they are less likely to be tolerant of these organisms. This may explain why individuals who are atopic are less likely to have evidence of previous infection with hepatitis A and other enteric organisms although they are just as likely to have been infected with respiratory pathogens.
Expression of Messenger RNA Coding for 5‐HT Receptor, Alpha and Beta Adrenoreceptor (Subtypes) during Oestrus and Dioestrus in the Bovine Uterus
Authors: Ontsouka E. C. , Reist M. , Graber H. , Blum J. W. , Steiner A. , Hirsbrunner G.
Published: December 2004

Serotoninergic and adrenergic receptors (5‐HTR and AR) are involved in the regulation of uterine contractility. The objective of this study was to compare mRNA levels of 5‐HTR1A, 5‐HTR1B, 5‐HTR1D, 5‐HTR1F, 5‐HTR2A, 5‐HTR2B, 5‐HTR2C, 5‐HTR4 and α1A, α1B, α1D, α2AD, α2B, α2C, and β1, β2, β3‐AR in oestrus and dioestrus, and at three uterine locations (tip, middle and base) using quantitative real‐time polymerase chain reaction. Uterine specimens consisting of endometrium and myometrium including vessels and serosa were collected from cows in oestrus (n = 10) and dioestrus (n = 15) respectively. Levels of 5‐HTR and AR mRNA were expressed relative to the geometric mean of ribosomal RNA (18S), ubiquitin and glyceraldehyde phosphate dehydrogenase by the mean values of geNorm algorithm. 5‐HTR1A, 5‐HTR2C and β3‐AR mRNA could not be detected in uterine tissues. The mRNA levels of 5‐HTR1F and 5‐HTR2B were lower (P < 0.05), but of 5‐HTR4 were higher (P < 0.05) in oestrus than in dioestrus. The mRNA levels of α1A‐AR, α2AD‐AR, α2B‐AR were lower (P < 0.05), but of α2C‐AR and β2‐AR were higher (P < 0.05) in oestrus than dioestrus. The mRNA levels of 5‐HTR1B and 5‐HTR1D (oestrus) and of α2AD‐AR (dioestrus) differed among uterine locations (base > middle > tip; P < 0.05). The mRNA expression of 5‐HTR and AR (subtypes) in bovine uterus was associated with cycle activity and varied according to uterine location. Additional studies on protein level will be carried out in order to elucidate the role of these receptor families on uterine contractility, which may then help to clarify clinical relevance.
The Relaxant Effect of Vasoactive Intestinal Polypeptide in the Isolated Canine Uterine Artery: The Role of Endothelium
Authors: Pešić S. , Grbović L. , Radenković M. , Stojić D. , Nikolić V. , Cvetković Z.
Published: December 2004

The purpose of this study was to examine the effect of vasoactive intestinal polypeptide (VIP) on the uterine artery obtained from non‐pregnant dogs. VIP (3 × 10−9–3 × 10−7 m) induced concentration‐dependent relaxation in canine uterine arteries with intact endothelium, pre‐contracted with l0−5 m phenylephrine (pEC50 = 7.52 ± 0.02, maximal response was 82.19 ± 2.15%, n = 36). The administration of the cyclooxygenase inhibitor indomethacin (l0−5 m) or 4‐aminopyridine (4‐AP), a blocker of potassium channels (l0−5 m), did not modify the relaxation induced by VIP. Contrary to this, NG‐nitro‐l‐arginine (l‐NOARG) (10−5 m) inhibited relaxation is evoked by VIP. Indomethacin applied with l‐NOARG did not provoke further inhibition of VIP‐induced relaxation. In the presence of both l‐NOARG and l‐NOARG + indomethacin, 4‐AP led to the further inhibition of VIP‐induced relaxation of canine uterine artery. It is concluded that VIP induces endothelium‐dependent relaxation of uterine arteries of non‐pregnant dogs, which can be entirely explained by the production of nitric oxide (NO) from the endothelial cells. We proposed that when NO synthesis is inhibited, VIP induces further relaxation, independent of the edothelium‐derived relaxing factors, probably through activation of K+ channels.
Effects of Erythromycin on Myoelectric Activity of the Spiral Colon of Dairy Cows
Authors: Zanolari P. , Steiner A. , Meylan M.
Published: December 2004

The effects of erythromycin on myoelectric activity of the spiral colon of dairy cows were investigated in a prospective study. Four Simmental × Red‐Holstein crossbred cows of similar body weight and condition with seven pairs of bipolar electrodes implanted in the intestine (one each in the distal ileum, caecum and proximal colon, and four in the spiral colon) were included. Erythromycin lactobionate (1 mg kg−1) and 0.9% sodium chloride solution (NaCl) were administered to each cow in a random order. Erythromycin was diluted with NaCl and both treatments were administered slowly intravenously over a period of 5 min 1 h after onset of a phase III of the bovine colonic migrating myoelectric complex (bcMMC). A 3–6‐day washout period was scheduled between trials. Significant differences between the results of the treatments were observed for spike duration in phase I as well as for spike duration and duration of spiking activity during phase II of the second bcMMC, which were significantly higher after erythromycin treatment than after NaCl. These findings suggest an indirect effect of erythromycin on colonic motility in cattle.
Age‐related changes in activities of daily living ability
Authors: Hayase Dale , Mosenteen Desiree , Thimmaiah Deepa , Zemke Sarah , Atler Karen , Fisher Anne G.
Published: December 2004

The objective of this study was to examine the relation between activities of daily living (ADL) ability and age among well people between three and 93 years of age. The study is one of descriptive comparison in design. Existing data from the international Assessment of Motor and Process Skills (AMPS) database were examined. The participants constituted a sample of 4398 persons who met the inclusionary criteria. All participants were evaluated using the Assessment of Motor and Process Skills (AMPS). The results showed that ADL ability increased sharply from 3 to 6 years and continued to improve beyond six until 15 years. After age 15 years, ADL performance ability plateaued until age 50 where it began to gradually decline through to the end of the age range studied. This research has implications for the practice of occupational therapy in determining the need for service and establishing goals based on the identification of people whose ADL performances are below age expectations.
Approach to a child with chronic liver disease
Authors: MIELI‐VERGANI GIORGINA , VERGANI DIEGO
Published: December 2004

Abstract  Chronic liver disease is suspected on the basis of clinical and laboratory features. The former include a positive past or family history for liver disease, a prolonged duration of what looks like an acute hepatitic illness, presentation with complications of portal hypertension, like bleeding varices or hypersplenism, signs of chronic liver disease on examination, like hard liver, splenomegaly, ascites, and cutaneous stigmata of chronic liver damage. Typical laboratory features are low albumin, prolongation of prothrombin time usually responsive to vitamin K, high gammaglobulins. Differential diagnosis of chronic liver disease requires specific laboratory tests for viral hepatitis, autoimmune liver disease, metabolic disorders and evaluation of the liver histology to confirm the diagnosis or to assess disease severity.
Debate on live related liver transplant: Pro
Authors: FAN SHEUNG TAT
Published: December 2004

Abstract  Live donor liver transplantation (LDLT) in adults is life saving for patients with fulminant hepatic failure, acute on chronic liver failure and end‐stage cirrhosis, particularly in Asia where cadaveric organ donation is scarce. Without this modality, 50% of adult patients waiting for deceased donor liver grafts and 95% of patients with fulminant hepatic failure died. With right lobe LDLT, the overall survival rate of patients with fulminant hepatic failure increases from 5–50% and the transplant rate of patients waiting for deceased donor grafts increased from 13–42%.
Mallory bodies and liver diseases
Authors: DENK H , STUMPTNER C , FUCHSBICHLER A , ZATLOUKAL K
Published: December 2004

Abstract  Mallory bodies are cytoplasmic inclusions in hepatocytes consisting of abnormal keratins, ubiquitin and several proteins (p62, heat shock proteins) involved in the unfolded protein response. They are morphologic hallmarks of alcoholic and nonalcoholic steatohepatitis but may also be associated with metabolic and toxic liver cell injury and hepatocellular neoplasms. Mallory bodies can be experimentally produced in mouse liver by chronic intoxication with griseofulvin or 3,5‐diethoxycarbonyl‐1,4‐dihydrocollidine (DDC). Mallory body formation is associated with derangement of the keratin intermediate filament cytoskeleton of the hepatocyte. The analysis of Mallory body composition and particularly their experimental induction in animal models and in tissue culture cells disclosed a major role of oxidative stress in the underlying liver cell injury.
Diagnosis of hepatitis C: update 2004
Authors: SARRAZIN CHRISTOPH
Published: December 2004

Abstract  Diagnosis of hepatitis C virus infection (HCV) is based on HCV antibody testing by standard serological tests and immunoblot assays for confirmation in special cases. Differentiation of past and ongoing hepatitis C is performed by detection of HCV core antigen and HCV RNA. Ongoing hepatitis C can be assigned to infection with one or multiple HCV sub‐ and genotypes by characteristic sequence differences. Infection with HCV genotype 2 or 3 is the best pretreatment parameter for prediction of sustained virologic response to interferon‐alfa based antiviral therapy. During antiviral therapy, the key to assess virologic treatment response is quantitative measurement of HCV RNA. A decline of HCV RNA concentration from baseline to week 12 of less than 2 log steps or an absolute viral load above 30.000 IU/mL in genotype 1 infected patients is strongly associated with viral non‐response. For estimation of early virologic response on the basis of HCV core antigen measurement positive detection of core antigen at week 12 was correlated with virologic non‐response. At week 24 of treatment, at the end‐of‐therapy and during follow‐up highly sensitive HCV RNA detection assays are critical for discontinuation of further therapy and correct estimation of virologic response. Mutational analysis of different HCV regions (hypervariable region 1, non‐structural protein 5A) may provide additional information about sensitivity/resistance to interferon‐based antiviral therapy but have not yet introduced into clinical practice.
Renal transplantation in chronic hepatitis C
Authors: GANE EDWARD
Published: December 2004

Abstract  Hepatitis C virus (HCV) infection is present in 2–70% of patients receiving hemodialysis. The major risks for transmission are transfusions and nosocomial spread within dialysis units and the incidence has declined dramatically following the introduction of universal precautions and blood and organ donor screening. Renal transplantation confers an overall survival benefit in HCV+ hemodialysis patients, with similar 5‐year patient and graft survival to those without HCV infection. However, long‐term studies (more than 10 years) have reported increased liver‐related and sepsis‐related mortality in HCV‐infected recipients. Attempts to eradicate HCV prior to transplant have been disappointing. Interferon is poorly tolerated in patients with end‐stage renal disease and ribavirin is contraindicated because of universal severe hemolysis related to reduced renal clearance. Interferon is associated with unacceptable rates of allograft dysfunction and loss (attributed to interferon‐induced rejection).
Poor response to HBV vaccination and strategies to enhance immunogenicity
Authors: CHANG MEI‐HWEI
Published: December 2004

Abstract  Hepatitis B vaccination has been proved to be effective in preventing acute and chronic hepatitis B virus (HBV) infection, fulminant hepatitis, and hepatocellular carcinoma. Approximately 5 to 15% of infants and at least 5 to 10% of most healthy adult population failed to produce protective levels of antibodies to HBV vaccination.

The main causes of poor response to HBV vaccination includes intrauterine infection, vaccine escape mutants, genetic hypo‐or non‐responsiveness to hepatitis B surface antigen (HBsAg) and immune compromised host.

Strategies to enhance immunogenicity to HBV vaccination are as the following: (1) overcome intrauterine or perinatal transmission by antiviral therapy for high risk pregnant women during last trimester, or immediately after birth with HBV hyperimmune globulin for the neonates; (2) higher dosage or more doses of HBV vaccine; (3) better vaccines ; (4) enhance host immune status; (5) better compliance of the vaccines.

In conclusion, current hepatitis B vaccination has been proved to be effective in controlling acute and chronic HBV infection and its complication. Yet further efforts to improve its efficacy generally and in high risk subjects and in immune compromised hosts are needed.
Hepatitis C viral kinetics
Authors: HERRMANN EVA , SARRAZIN CHRISTOPH
Published: December 2004

Abstract  Standard therapy with (pegylated) interferon‐alfa and ribavirin still leads to sustained virologic response rates of 50–60%, only. Therefore, new therapeutic strategies are required. With the analysis of mathematical models of hepatitis C viral kinetics, individual kinetic rates as infected cell loss, clearance of free virus, and an efficiency factor on blocking viral production can be estimated. They can be used to summarize and quantify the initial response to antiviral therapy and, furthermore, allow the assessment of treatment mechanisms, prediction of treatment response, and the efficient identification of viral and host factors on treatment response. They may even be used for optimizing and individualizing therapy.
Molecular mechanisms in the pathogenesis of cirrhotic portal hypertension: focus on nitric oxide
Authors: SHAH VIJAY
Published: December 2004

Abstract  Portal hypertension occurs because of increased intrahepatic resistance in addition to increased portal venous inflow. Nitric oxide (NO) is a gaseous molecule implicated in several of the vascular derangements that characterize and contribute to portal hypertension and this will be the focus of this review article. In the intrahepatic circulation, NO bioavailability is diminished due to defects in endothelial NO synthase (eNOS) regulation that contribute to increased intrahepatic resistance. NO bioavailability is increased in the splanchnic and systemic circulation because of increased eNOS protein expression and eNOS enzyme activation, which contributes to splanchnic vasodilation and increased portal venous inflow. Therapies to modulate NO bioavailability in portal hypertension are under investigation in humans and animal models.