bluuebunny/crossref_metadata_2025_split huggingface dataset:
Luminal morphology of the avian lower intestine: Evidence supporting the importance of retrograde peristalsis for water conservation
Authors: Casotti Giovanni 
Published: August 2002

AbstractTissue from the lower intestine of two species of sparrow, the house sparrow Passer domesticus and savannah sparrow Passerculus sandwichensis was sectioned in an unbiased manner and examined quantitatively using stereology. The tissue was processed for light microscopy, and scanning and transmission electron microscopy to examine the extent to which microvilli enhanced the epithelial surface area of the cecae, rectum, and coprodeum. Parameters measured included individual microvillus surface area, microvilli packing density, and absolute surface area. In both species, the average surface area, packing density, and absolute surface area of microvilli decreased distally along the rectum and coprodeum. All three measured variables were not statistically significant (P > 0.05) between species. Surface area amplification on the cecae due to microvilli was low, and approximated values equivalent to distal regions of the rectum and coprodeum. In the cecae, microvilli within the savannah sparrow had a significantly higher (P < 0.05) individual surface area, packing density, and absolute surface area than in the house sparrow. The functional implications of a change in microvilli population are discussed in relation to retrograde peristalsis within the lower intestine of birds. Anat Rec 263:289–296, 2001. © 2001 Wiley‐Liss, Inc.
Reappraisal of the vomeronasal system of catarrhine primates: Ontogeny, morphology, functionality, and persisting questions
Authors: Smith Timothy D. , Siegel Michael I. , Bhatnagar Kunwar P. 
Published: August 2002

AbstractThe vomeronasal organ (VNO) is a chemosensory organ that functions in sociosexual communication in many vertebrates. In strepsirhine primates and New World monkeys, the bilateral VNOs are traditionally understood to exist as a well‐developed chemosensory epithelial unit. In contrast, the VNOs of catarrhine primates are thought to be absent or exist only as reduced epithelial tubes of uncertain function. However, the VNO of New World monkeys shows substantial variation in the extent of sensory epithelium. Recent findings that the chimpanzee (Pan troglodytes) possesses a VNO similar to humans suggest the variability of the VNO among haplorhine primates may be more extensive than previously thought, and perhaps more at par with that observed in chiropterans. The atypical histologic structure and location of the human/chimpanzee VNO suggest accessory glandular secretion and transport functions. Other catarrhine primates (e.g., Macaca spp.), may truly be characterized by VNO absence. Unique aspects of facial growth and development in catarrhine primates may influence the position or even presence of the VNO in adults. These recent findings demonstrate that previous investigations on some catarrhine primates may have missed the VNO and underestimated the extent of variability. As an understanding of this variation increases, our view of VNO functionality and associated terminology is changing. Further investigations are needed to consider phylogenetic implications of VNO variability and the association of craniofacial form and VNO anatomic position in primates. Anat Rec (New Anat) 265:176–192, 2001. © 2001 Wiley‐Liss, Inc.
Introduction
Authors: Stanley David W. 
Published: August 2002

AbstractColleagues,It is a pleasure to introduce a group of three papers on insect G protein‐coupled receptors, from a symposium organized by Professor Jozef Vanden Broeck. This symposium, held August, 2000 at the XXI International Congress of Entomology in Brazil, represents one of the frontiers of biology and insect science. Professor Vanden Broeck has agreed to serve as Guest Editor for these papers, in which the contributors illuminate that frontier.Study of signal transduction mechanisms is a unifying, multidisiplinary activity that links many traditional fields of biology. Extracellular signals influence events within cells through a number of signal transduction mechanisms. G protein‐coupled receptors is one of the mechanisms. Many ligands, including hormones, prostaglandins and biogenic amines to name just a few, exert their cellular actions by interacting with specific G protein‐coupled receptors. Appreciating the broad variety of these receptors and the associated signal transducton mechanisms is a major advance in our field. We invite you to share in the insights and excitement of this advance.
Relative lung and systemic bioavailability of sodium cromoglycate inhaled products using urinary drug excretion post inhalation
Authors: Aswania Osama , Chrystyn Henry 
Published: August 2002

AbstractThe relative lung and systemic bioavailability of sodium cromoglycate following inhalation by different methods have been determined using a urinary excretion pharmacokinetic method. On three separate randomised study days, 7 days apart, subjects inhaled (i) 4×5 mg from an Intal® metered dose inhaler (MDI), (ii) 4×5 mg from an MDI attached to a large volume spacer (MDI+SP) and (iii) 20 mg from an Intal Spinhaler® (DPI). Urine samples were provided at 0, 0.5, 1, 2, 5 and 24 h post dose. The mean (S.D.) amount of sodium cromoglycate excreted in the urine during the first 30 min post inhalation was 38.1 (27.5), 222.3 (120.3) and 133.1 (92.2) μg following MDI, MDI+SP and DPI, respectively. The mean ratio (90% confidence interval) of these amounts excreted in the urine over the first 30 min for MDI+SP vs MDI, DPI vs MDI and MDI+SP vs DPI was 801.0 (358.0, 1244; p<0.002)%, 457.0 (244.0, 670.0; p<0.02)% and 262.4 (110.2, 414.5)%, respectively. Similarly for the 24 h cumulative amount of sodium cromoglycate excreted over the 24 h post inhalation the ratios were 375.4 (232.9, 517.9; p<0.005)%, 287.5 (183.4, 391.6; p<0.02)% and 211.4 (88.3, 334.5)%, respectively. The results highlight better lung deposition of sodium cromoglycate from a metered dose inhaler attached to a large volume spacer. Copyright © 2002 John Wiley & Sons, Ltd.
A pH‐dependent variation in α‐helix structure of the S‐peptide of ribonuclease A studied by Monte Carlo simulated annealing
Authors: Nakazawa Takashi , Ban Sumiko , Okuda Yuka , Masuya Masato , Mitsutake Ayori , Okamoto Yuko 
Published: August 2002

AbstractLow‐energy conformations of the S‐peptide fragment (20 amino acid residues long) of ribonuclease A were studied by Monte Carlo simulated annealing. The obtained lowest‐energy structures have α‐helices with different size and location, depending distinctively on the ionizing states of acidic amino acid residues. The simulation started from completely random initial conformation and was performed without any bias toward a particular structure. The most conspicuous α‐helices arose from the simulation when both Glu 9 and Asp 14 were assumed to be electrically neutral, whereas the resulting conformations became much less helical when Asp 14 rather than Glu 9 was allowed to have a negative charge. Together with experimental evidence that the α‐helix in the S‐peptide is most stable at pH 3.8, we consider the helix formation need the carboxyl group of Asp 14 to be electrically neutral in this weakly acidic condition. In contrast, a negative charge at Asp 14 appears to function in support of a view that this residue is crucial to helix termination owing to its possibility to form a salt bridge with His 12. These results indicate that the conformation of the S‐peptide depends considerably on the ionizing state of Asp 14. © 2002 John Wiley & Sons, Inc. Biopolymers 63: 273–279, 2002; DOI 10.1002/bip.10055
Establishing structure–function relationships for eumelanin
Authors: Nofsinger J. Brian , Weinert Emily E. , Simon John D. 
Published: August 2002

AbstractThe aggregation‐dependent optical properties of eumelanin from human hair are examined. When aggregation is increased, the absorption spectrum extends to lower energy. The absorption spectra of oligomers isolated from black human hair and Sepia officinalis are comparable and are in quantitative agreement with the reported action spectra for photoinduced oxygen consumption and free‐radical generation by eumelanin. The agreement between the optical properties of human hair and squid eumelanins suggests the fundamental molecular constituents of the pigments are similar and aggregation‐dependent photophysical behavior is a general feature of all eumelanins. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 302–305, 2002
Mobility measurements of immunomagnetically labeled cells allow quantitation of secondary antibody binding amplification
Authors: McCloskey Kara E. , Comella Kristin , Chalmers Jeffrey J. , Margel Shlomo , Zborowski Maciej 
Published: August 2002

AbstractMagnetic cell separation methods commonly utilize paramagnetic materials conjugated to antibodies that target specific cell surface molecules. The amount of magnetic material bound to a cell is directly proportional to the magnetophoretic mobility of that cell. A mathematical model has been developed which characterizes the fundamental parameters controling the amount of magnetic material bound, and thus, the magnetophoretic mobility of an immunomagnetically labeled cell. In characterization of the paramagnetic labeling, one of the parameters of interest is the increase in magnetophoretic mobility due to the secondary antibody binding to multiple epitopes on the primary antibody, referred to as the “secondary antibody binding amplification,” Ψ. Secondary antibody‐binding amplification has been investigated and quantitated by comparing the mobilities of lymphocytes directly labeled with anti‐CD4 MACS™ (Miltenyi Biotec, Auburn, CA) magnetic nanoparticle antibody with the mobilities of lymphocytes from the same sample labeled with two different indirect antibody‐labeling schemes. Each indirect labeling scheme incorporated a primary mouse anti‐CD4 FITC antibody that provides both FITC and mouse‐specific binding sites for two different secondary antibody‐magnetic nanoparticle conjugates: either anti‐FITC MACS magnetic nanoparticle antibody or anti‐mouse MACS magnetic nanoparticle antibody. The magnetophoretic mobilities of the immunomagnetically labeled cells were obtained using Cell Tracking Velocimetry (CTV). The results indicate that an average of 3.4 anti‐FITC MACS magnetic nanoparticle antibodies bind to each primary CD4 FITC antibody, Ψ1,2f = 3.4 ± 0.33, and that approximately one, Ψ1,2m = 0.98 ± 0.081, anti‐mouse MACS magnetic nanoparticle antibody binds to each primary mouse CD4 FITC antibody on a CD4 positive lymphocyte. These results have provided a better understanding of the antibody‐binding mechanisms used in paramagnetic cell labeling for magnetic cell separation. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 642–655, 2001.
Simultaneous degradation of organophosphorus pesticides and p‐nitrophenol by a genetically engineered Moraxella sp. with surface‐expressed organophosphorus hydrolase
Authors: Shimazu Mark , Mulchandani Ashok , Chen Wilfred 
Published: August 2002

AbstractMoraxella sp., a native soil organism that grows on p‐nitrophenol (PNP), was genetically engineered for the simultaneous degradation of organophosphorus (OP) pesticides and p‐nitrophenol (PNP). The truncated ice nucleation protein (INPNC) anchor was used to target the pesticide‐hydrolyzing enzyme, organophosphorus hydrolase (OPH), onto the surface of Moraxella sp., alleviating the potential substrate uptake limitation. A shuttle vector, pPNCO33, coding for INPNC–OPH was constructed and the translocation, surface display, and functionality of OPH were demonstrated in both E. coli and Moraxellasp. However, whole cell activity was 70‐fold higher in Moraxellasp. than E. coli. The resulting Moraxella sp. degraded organophosphates as well as PNP rapidly, all within 10 h. The initial hydrolysis rate was 0.6 μmol/h/mg dry weight, 1.5 μmol/h/mg dry weight, and 9.0 μmol/h/mg dry weight for methyl parathion, parathion, and paraoxon, respectively. The possibility of rapidly degrading OP pesticides and their byproducts should open up new opportunities for improved remediation of OP nerve agents in the future. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 76: 318–324, 2001.
Zeolite molecular sieves have dramatic acid–base effects on enzymes in nonaqueous media
Authors: Fontes Nuno , Partridge Johann , Halling Peter J. , Barreiros Susana 
Published: August 2002

AbstractZeolite molecular sieves very commonly are used as in situ drying agents in reaction mixtures of enzymes in nonaqueous media. They often affect enzyme behavior, and this has been interpreted in terms of altered hydration. Here, we show that zeolites can also have dramatic acid–base effects on enzymes in low water media, resulting from their cation‐exchange ability. Initial rates of transesterification catalyzed by cross‐linked crystals of subtilisin were compared in supercritical ethane, hexane, and acetonitrile with water activity fixed by pre‐equilibration. Addition of zeolite NaA (4 Å powder) still caused remarkable rate enhancements (up to 20‐fold), despite the separate control of hydration. In the presence of excess of an alternative solid‐state acid–base buffer, however, zeolite addition had no effect. The more commonly used Merck molecular sieves (type 3 Å beads) had similar but somewhat smaller effects. All zeolites have ion‐exchange ability and can exchange H+ for cations such as Na+ and K+. These exchanges will tend to affect the protonation state of acidic groups in the protein and, hence, enzymatic activity. Zeolites pre‐equilibrated in aqueous suspensions of varying pH‐pNa gave very different enzyme activities. Their differing basicities were demonstrated directly by equilibration with an indicator dissolved in toluene. The potential of zeolites as acid–base buffers for low‐water media is discussed, and their ability to overcome pH memory is demonstrated. © 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 296–305, 2002.
The simultaneous biosynthesis and uptake of amino acids by Lactococcus lactis studied by 13C‐labeling experiments
Authors: Jensen Niels Bang Siemsen , Christensen Bjarke , Nielsen Jens , Villadsen John 
Published: August 2002

AbstractUniformly 13C labeled glucose was fed to a lactic acid bacterium growing on a defined medium supplemented with all proteinogenic amino acids except glutamate. Aspartate stemming from the protein pool and from the extracellular medium was enriched with 13C disclosing a substantial de novo biosynthesis of this amino acid simultaneous to its uptake from the growth medium and a rapid exchange flux of aspartate over the cellular membrane. Phenylalanine, alanine, and threonine were also synthesized de novo in spite of their presence in the growth medium. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 11–16, 2002; DOI 10.1002/bit.10211
PLS score–loading correspondence and a bi‐orthogonal factorization
Authors: Ergon Rolf 
Published: August 2002

AbstractIt is established industrial practice to use the correspondence between partial least squares (PLS) scores and loadings or loading weights as a means for process monitoring and control. Deviations from the normal operating point in a score plot are then related to the influences from major process variables as shown in a loading or loading weight plot. These relations are often presented in a bi‐plot, i.e. appropriately scaled scores and loadings or loading weights are displayed in the same plot. As shown in the present paper, however, the orthogonal PLS algorithm of Wold gives no direct theoretical and graphical correspondence, i.e. the bi‐plot will show an angle deviation that causes an interpretational problem. The alternative non‐orthogonal PLS algorithm of Martens gives direct correspondence, but the correlated latent variables may then cause another interpretational problem. As a solution to these problems, this paper presents a PLS factorization where both scores and loadings are orthogonal (BPLS), and we show how the Wold and Martens factorizations can easily be transformed to this solution. The result is independent latent variables as well as direct score and loading correspondence. It is also shown that the transformations involved do not affect the predictor found by PLS regression. The score–loading correspondence properties for the different PLS factorizations are discussed using principal component analysis (PCA) as a reference case. An example using industrial paper plant data is included. Copyright © 2002 John Wiley & Sons, Ltd.
Immobilization of difunctional building blocks on hydroxysuccinimide activated silica: Versatile in situ preparation of chiral stationary phases
Authors: Kosjek Birgit , Uray Georg 
Published: August 2002

AbstractSeveral brush‐type chiral stationary phases (CSPs) based on undecanoyl‐ or butanoyl‐bound (R,R)‐1,2‐diphenylethane‐1,2‐diamine (DPEDA) as chiral selector were prepared by an innovative, fast, and less expensive kind of preparation. The key to this method is the immobilization of the enantiomeric pure diamine with only one amino function in a simple substitution reaction on hydroxysuccinimide ester‐activated silica. No excess chiral material is lost. Loading can be easily monitored analyzing the filtrate. The free second amino function can subsequently be acylated with different acyl halogenides. Examples with benzoyl‐ and 3,5‐dinitrobenzoyl (DNB) amides show that, based on our new approach, a library of differently acylated Pirkle‐type CSPs can easily be obtained. A benzoylated analog of the commercially available ULMO CSP is shown to be very effective in separating enantiomers of N‐acyl amino acids. Chirality 13:657–667, 2001. © 2001 Wiley‐Liss, Inc.
Immunohistochemical localization of DARPP‐32 in the brain of the lizard, Gekko gecko: Co‐occurrence with tyrosine hydroxylase
Authors: Smeets Wilhelmus J.A.J. , Lopez Jesus M. , González Agustín 
Published: August 2002

AbstractTo assess the relationship between dopaminergic neuronal structures and dopaminoceptive structures in a reptile, single and double immunohistochemical procedures with antibodies directed against DARPP‐32 (dopamine‐ and cAMP‐regulated phosphoprotein with an apparent molecular mass of 32,000 daltons),a phosphoprotein related to the dopamine D1‐receptor, and tyrosine hydroxylase (TH) were applied to the brain of the lizard, Gekko gecko. The DARPP‐32 antibody yielded a well‐differentiated pattern of staining in the brain of Gekko. In general, areas that are densely innervated by TH‐immunoreactive, putative dopaminergic fibers, such as the nucleus accumbens, striatum, dorsal ventricular ridge, and amygdaloid complex, display strong immunoreactivity for DARPP‐32 in somata and neuropil. Distinct cellular DARPP‐32 immunoreactivity was also found in the lateral cortex, ventral hypothalamus, habenula, central nucleus of the torus semicircularis, midbrain tectum, parvicellular isthmic nucleus, raphe nuclei, caudal rhombencephalic tegmentum, and spinal cord. Striatal projections to the midbrain and their target, i.e., the substantia nigra pars reticulata, were found to be strongly immunoreactive. Double immunofluorescence staining revealed that dopaminergic cells generally do not stain for DARPP‐32, except for cells in the ventral hypothalamus and at caudal rhombencephalic levels. In conclusion, the distribution of DARPP‐32 in the brain of the lizard Gekko gecko largely resembles the pattern observed in birds and mammals, at least as far as basal ganglia structures are concerned. On the other hand, there are several specific features of DARPP‐32 distribution in the gekkonid brain that deserve further attention, such as cellular colocalization of DARPP‐32 and TH immunoreactivity in hypothalamic and caudal rhombencephalic areas, and cellular DARPP‐32 immunoreactivity in the tectum and central nucleus of the torus semicircularis of the midbrain, the superior and inferior raphe nuclei, and the spinal cord. J. Comp. Neurol. 435:194–210, 2001. © 2001 Wiley‐Liss, Inc.
Concurrent measurement of the survival of two populations of rabbit platelets labeled with either two PKH lipophilic dyes or two concentrations of biotin
Authors: Rand M.L. , Wang H. , Mody M. , Chu I. , Treutiger I. , Nguyen A. , Packham M.A. , Freedman J. 
Published: August 2002

AbstractBackgroundTo avoid radioisotopic labeling and permit comparison of the survival of two platelet populations concurrently in one animal, we compared simultaneous recoveries and survival times of homologous rabbit platelets labeled in vitro with the lipophilic dyes PKH26 (red fluorescing) and PKH67 (green fluorescing) and with two levels of biotin (low, 1 μg/ml; high, 10 μg/ml).MethodsBlood samples were drawn up to 96 h postinfusion and analyzed by flow cytometry. Biotin‐labeled samples were incubated with phycoerythrin‐streptavidin before analysis.ResultsRecovery of PKH26‐labeled platelets at 1 h was lower (37.5%) than that of PKH67‐labeled platelets (47.3%; P < 0.001). Platelet survival times were 62.4 and 61.9 h. Recoveries at 1 h of platelets labeled with two levels of biotin were similar (86.6% and 84.6%) and greater than those of PKH‐labeled platelets (P < 0.001). Survival of platelets labeled with biotin did not differ (low, 83.3 h; high, 85.2 h) and was longer than for PKH‐labeled platelets (P < 0.01). Labeling methods did not activate platelets (measured by P‐selectin expression), nor did they affect platelet responses to adenosine diphosphate (ADP), collagen, or thrombin.ConclusionsLabeling with two levels of biotin is superior to labeling with PKH dyes, and is useful for measuring concurrently the survival of two differing platelet populations. Cytometry 47:111–117, 2002. © 2002 Wiley‐Liss, Inc.
Simultaneous blockade of Fcγ receptors and indirect labeling of mouse lymphocytes by the selective detection of allotype‐restricted epitopes on the kappa chain of rat monoclonal antibodies
Authors: Balogh Péter , Tew John G. , Szakal Andras K. 
Published: August 2002

AbstractBackgroundIncubation of mouse hemopoietic cells with rat monoclonal antibodies (mAbs) of the IgG class sometimes results in Fc‐region mediated binding of immunoglobulins by Fc‐receptors. This unwanted binding can be prevented by preincubation of target cells with the rat anti‐mouse anti‐CD16/32 (2.4G2) mAb.MethodsTo avoid the cross‐reactivity of fluorochrome‐conjugated secondary anti‐rat antibodies with the Fc‐receptor blocking 2.4G2, direct fluorochrome‐conjugated immunoglobulins need to be used. However, we report that a mouse mAb (MRC OX12) with a strong rat Igka allotype preference can be used for flow cytometric measurements in conjunction with unlabeled rat mAbs with the simultaneous blockade of Fcγ receptors by the 2.4G2 mAb.Results and DiscussionThis lack of reactivity of OX12 against the 2.4G2 mAb is remarkable, as it could efficiently detect another Sprague‐Dawley–derived rat mAb. This staining procedure (unlabeled rat mAb of the appropriate strain detected by OX12 mAb in the presence of 2.4G2 IgG) is an attractive alternative to using direct antibody conjugates, while satisfying the need for an effective Fcγ‐receptor blockade. Cytometry 47:107–110, 2002. © 2002 Wiley‐Liss, Inc.