bluuebunny/crossref_metadata_2025_split huggingface dataset:
Postnatal regression of glucose transport in a patient with glycogen storage disease type 1b
Authors: Levy J. , Abu‐Ras M. T. , Berenstein T. , Potashnik R. , Meisner I. , Moses S. W. , Bashan N. 
Published: December 2004

SummaryDecreased 2‐deoxyglucose (2‐DOG) uptake is well described in the neutrophils of patients with glycogen storage disease type 1b (GSD 1b). We report a patient with GSD 1b who presented with a normal antenatal and perinatal 2‐deoxyglucose uptake that showed a slow regression during the first months of life. These indicate limitations of 2‐deoxyglucose uptake in the diagnosis of GSD 1b. While it appears that low uptake rate below 0.25 nmol/min in 106 cells is of significance, normal uptake does not rule out the presence of the disease. It seems that antenatal diagnosis of GSD 1b cannot be made by measurement of 2‐deoxyglucose uptake in the fetal neutrophils.
Resistance to erucic acid as a selectable marker for peroxisomal activity: Isolation of revertants of an infantile Refsum disease cell line
Authors: El Bioukar Bachir , Straehli F. , Ng K. Heng , Rolland M. ‐O. , Hashimoto T. , Carreau J. ‐P. , Deschatrette J. 
Published: December 2004

SummaryA system based on the ability of cells to oxidize very long‐chain fatty acids (VLCFA) was developed to selectin vitro normal human fibroblasts from fibroblasts of patients suffering from peroxisomal disorders with multienzymatic deficiencies: Zellweger syndrome, neonatal adrenoleukodystrophy, infantile Refsum disease (IRD). Cells treated with various concentrations of erucic acid (C22:1 n‐9) revealed an enhanced toxicity of this fatty acid for the fibroblasts of patients compared with normal cells. This differential toxicity is correlated with variable accumulations of C22:1 n‐9 and the absence of β‐oxidation products in the mutants.Revertants from clonal IRD cell lines were isolated in the selective medium at frequencies ranging from 3×10−7 to 4×10−6 depending on the line. After six weeks of growth in the absence of selective pressure, the variants exhibited a resistance level to C22:1 n‐9 identical to that of normal cells. Furthermore, β‐oxidation of VLCFA is re‐established in these selected cells as well as dihydroxyacetone phosphate acyltransferase activity. Immunoblot experiments also demonstrated a restored pattern of acyl‐CoA oxidase molecular forms. Last, immunofluorescence studies revealed the presence of cytoplasmic structures that were absent in the original IRD cells. Thus, both the deficiencies in metabolic pathways and paucity of the organelle are at least partially corrected in the selected clones.
Production and disposal of medium‐chain fatty acids in children with medium‐chain acyl‐CoA dehydrogenase deficiency
Authors: Heales S. J. R. , Thompson G. N. , Massoud A. F. , Rahman S. , Halliday D. , Leonard J. V. 
Published: December 2004

SummaryThe effect of fasting on plasma concentrations of fatty acids has been determined in four children with medium‐chain acyl‐CoA dehydrogenase (MCAD) deficiency. In addition, thein vivo rate of octanoate oxidation was measured, using [1‐13C]octanoate. In the three older children (1.5–11.2 years), fasting for up to 18 h stimulated lipolysis, as reflected by the increasing concentration of free fatty acids, but with little rise in concentrations of medium‐chain fatty acids, octanoate, decanoate andcis‐4‐decenoate. In an infant (0.5 year), lipolysis was greater and was accompanied by rising concentrations of medium‐chain fatty acids. After 13.5 h there was a rapid increase in the concentration of decanoate andcis‐4‐decenoate. The calculatedin vivo rate of octanoate oxidation was substantial in all patients studied (6.4–13.1 µmol/kg per h) despite very low MCAD activityin vitro. It is concluded that under basal conditions thein vivo oxidation rate of medium‐chain fatty acids is near normal in the four children studied with MCAD deficiency.
High‐resolution loading tests in the study of genetic heterogeneity in gangliosidosis fibroblasts
Authors: Akhunov V. S. , Mirenburg T. V. , Krasnopolskaya X. D. 
Published: December 2004

SummaryGM1‐ and GM2‐gangliosides were isolated from brain and radio‐labelled. The labelled moieties were localized by hydrolysis with lysosomal enzymes, followed by thin‐layer chromatography of the products. High‐resolution loading tests with labelled gangliosides were developed and found to differentiate infantile and juvenile forms of GM1‐ and GM2‐gangliosidoses as well as the identification of B, O and AB types of GM2‐gangliosidosis.
pH effects on the stability and dimerization of procaspase‐3
Authors: Bose Kakoli , Clark A. Clay 
Published: December 2004

AbstractpH‐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

AbstractDisulfide 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

AbstractRhodocetin 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

AbstractCovalent 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

AbstractThe 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

AbstractExtended 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.
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

AbstractThe 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

AbstractCathepsin 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

AbstractUpon 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

Summaryobjectives  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.
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.
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.