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PubMed2003

Rugby headgear study.

A two year randomised controlled trial of headgear in Rugby Union football is being conducted in Sydney, Australia. This paper gives an overview of this study in progress and presents results related to the development and laboratory performance of the headgear. The study commenced in 2002. Participants recruited to the study are in the under 13, 15, school open (U18) and colts age groups. There are three study arms: control, IRB-approved headgear, and modified headgear. The IRB approved headgear is a popular model in rugby, the Canterbury Honeycomb model manufactured by BodyArmour in New Zealand. The dimensions of this model were altered by increasing foam density and thickness to produce the modified headgear. In impact energy attenuation tests of 15 and 20 Joules onto a flat anvil, the modified headgear demonstrated average maximum headform accelerations of 23% and 33% of the standard model, respectively. Whether or not this improvement translates into reductions in injury will be determined by a comparison of the rates and severities of head injuries across study arms. Furthermore, these dimensional changes may not be acceptable to rugby players. Player attitudes towards safety and the use of protective clothing, injury history, experience and on-field behaviour will be examined via structured pre- and end of season surveys and analysis of match video.

Adolescent↗
PubMed1994

General strategy for structural analysis of the oligosaccharide region of lipooligosaccharides. Structure of the oligosaccharide component of Pseudomonas aeruginosa IATS serotype 06 mutant R5 rough-type lipopolysaccharide.

A general NMR-based strategy for the structural analysis of rough-type lipopolysaccharides, i.e., lipooligosaccharides, is introduced that involves initial deacylation of the glycolipids. The approach is illustrated here with the lipooligosaccharide (LOS) of the Pseudomonas aeruginosa serotype 06 rough-type mutant R5, which consists of a single major low molecular weight component. The LOS was isolated by using a modified phenol/chloroform/petroleum ether extraction method. Chemical analysis of the core oligosaccharide obtained from this LOS indicated that it was composed of D-glucose (D-Glc), 2-amino-2-deoxy-D-galactose (D-GalN), L-glycero-D-manno-heptose (L,D-Hep), 3-deoxy-D-manno-octulosonic acid (KDO), L-alanine (Ala), and phosphate. The glycan structure of the LOS was elucidated by employing a novel strategy that involved the use of one- and two-dimensional nuclear magnetic resonance techniques and mass spectrometric based methods on the backbone oligosaccharide obtained from the LOS by deacylation, dephosphorylation, and reduction of the terminal glucosamine. The location of phosphomonoester groups was unambiguously established by a 2D 1H-31P chemical shift correlation experiments on an O-deacylated sample of the LOS (LOS-OH). The LOS-OH carries amide-linked 3-hydroxydodecanoic acid groups and Ala on the two D-glucosamine residues and the D-galactosamine residue, respectively.

Antigens, Bacterial↗
PubMed2003

NMR and theoretical investigations on the structures and dynamics of octahedral bis(chelate)dichloro V(III) compounds isolated by an unusual reduction of non-oxo V(IV) species.

Reaction of the non-oxo V(IV) species [V(IV)Cl(2)(L(OO))(2)] [L(OO) = acetylacetonate (acac(-)) or benzoylacetonate (bzac(-))] with a chelate nitrogen-donor ligand L(NN) in acetonitrile leads to the reduction of V(IV) to V(III) and the formation of the mononuclear V(III) compounds of the general formula [V(III)Cl(2)(L(OO))(L(NN))] (L(OO) and L(NN) are acac(-) and bipy for 1; acac- and 5,5'-me(2)bipy for 2; acac(-) and 4,4'-tb(2)bipy for 3; acac(-) and phen for 4; bzac(-) and bipy for 5; bzac(-) and phen for 6). The reduction of the V(IV) complexes was monitored by GC-MS and (1)H NMR spectroscopy. Both one- and two-dimensional (2D COSY and 2D EXSY) (1)H NMR techniques were used to assign the observed (1)H NMR resonances of 1-6 in CD(2)Cl(2) or CDCl(3) solution. It appeared that in solution these V(III) complexes form two isomers which are in equilibrium: cis-[V(III)Cl(2)(L(OO))(L(NN))] <==> trans-[V(III)Cl(2)(L(OO))(L(NN))]. 2D EXSY cross-peaks were clearly observed between bipy- and acac-hydrogen atoms of the two geometrical isomers of 1-3 as well as between bipy and acac(-) protons of the cis isomer, indicating a dynamic process that corresponds to cis-trans isomerization and a cis-cis racemization. The thermodynamic and kinetic parameters of the equilibrium between these two isomers were calculated for compounds 1 and 2 by using variable temperature (VT) NMR data. Both cis-trans isomerization and cis-cis racemization processes probably proceed with an intramolecular twist mechanism involving a trigonal prismatic transition state. Density functional calculations (DFT) also indicated such a rearrangement mechanism.

Journal Article↗
PubMed2005

Dinuclear triple helicates with diazine ligands: X-ray structural, electrochemical, and magnetic studies.

A series of dinuclear complexes of Mn(III), Fe(III), and Co(III) with two diazine Schiff bases, H2salhn and H2mesalhn, is reported. The Schiff bases are prepared by condensation reactions of hydrazine with salicylaldehyde (H2salhn) and with 2-hydroxyacetophenone (H2mesalhn) in 1:2 mol ratio. X-ray crystallographic characterization reveals triple helical structures of [Co2(salhn)3], [Co2(mesalhn)3], and [Fe2(mesalhn)3]. In each complex, three dinucleating O,N,N,O donor ligands provide three diazine (=N-N=) bridges between the metal ions and facial O3N3 coordination spheres around them. The ligands are twisted about the N-N single bond and coordinate to the two metal ions in a helical fashion to generate the triple helical structure. The dicobalt(III) complex of mesalhn2- is D3-symmetric, while the diiron(III) analogue is very close to being of this symmetry. On the other hand, the dicobalt(III) complex of salhn2- significantly deviates from the ideal D3-symmetry due to the large range covered by the twist angles of the three ligands. In the crystal lattice of these complexes, intermolecular C-H...O, C-H...N, O-H...O, C-H...Cl, and pi-pi interactions involving the complex and the solvent molecules lead to one- and two-dimensional supramolecular structures. The complexes [Fe2(mesalhn)3] and [Co2(mesalhn)3] are redox active and display two successive metal-centered reductions on the cathodic side of Ag/AgCl reference electrode. Weak antiferromagnetic spin-coupling is operative between the two metal ions in [Mn2(salhn)3] (J = -0.57(1) cm(-1)) and in [Fe2(mesalhn)3] (J = -2.82(4) cm(-1)).

Acetophenones↗
PubMed2006

Identification of carbonylated protein in frozen rainbow trout (Oncorhynchus mykiss) fillets and development of protein oxidation during frozen storage.

Frozen storage of fish is known to enhance lipid oxidation, resulting in the development of an unpleasant rancid taste and odor. Frozen storage of fish is also known to reduce protein solubility, and proteins are expected to be oxidatively modified; however, these oxidative mechanisms are poorly understood. Generally, protein oxidation leads to a wide range of modifications; the most studied being the formation of carbonyl groups. The present work shows, by UV spectrophometric determination of protein carbonyl groups in rainbow trout muscle, that storage at -20 degrees C resulted in a 2-fold increase in protein carbonylation compared to storage at -30 or -80 degrees C. Furthermore, low-salt-soluble proteins in fish that were either fresh or stored for 3 years at -80 degrees C were found to have similar extents of carbonylation. Proteome analysis and two-dimensional immunoblotting of rainbow trout low-salt- and high-salt-soluble proteins gave a detailed description of the protein carbonylation pattern. Several carbonylated proteins were identified by LC-MS/MS, such as nucleoside diphosphate kinase, adenylate kinase, pyruvate kinase, actin, creatine kinase, tropomyosin, myosin light chains 1 and 2, and myosin heavy chain. Furthermore, the results showed a reduced solubility of nucleoside diphosphate kinase in fish stored at -20 degrees C for 2 years compared to fish stored at -80 degrees C. It was observed that low-abundant proteins could be relatively more carbonylated than high-abundant proteins, thereby indicating that some proteins are more susceptible to oxidation than others, due to either their cellular localization, amino acid sequence, or biochemical function.

Electrophoresis, Gel, Two-Dimensional↗
PubMed2005

Ellipsometric and neutron diffraction study of pentane physisorbed on graphite.

High-resolution ellipsometry and neutron diffraction measurements have been used to investigate the structure, growth, and wetting behavior of fluid pentane (n-C(5)H(12)) films adsorbed on graphite substrates. We present isotherms of the thickness of pentane films adsorbed on the basal-plane surfaces of a pyrolytic graphite substrate as a function of the vapor pressure. These isotherms are measured ellipsometrically for temperatures between 130 and 190 K. We also describe neutron diffraction measurements in the temperature range 11-140 K on a deuterated pentane (n-C(5)D(12)) monolayer adsorbed on an exfoliated graphite substrate. Below a temperature of 99 K, the diffraction patterns are consistent with a rectangular centered structure. Above the pentane triple point at 143.5 K, the ellipsometric measurements indicate layer-by-layer adsorption of at least seven fluid pentane layers, each having the same optical thickness. Analysis of the neutron diffraction pattern of a pentane monolayer at a temperature of 130 K is consistent with small clusters having a rectangular-centered structure and an area per molecule of approximately 37 A(2) in coexistence with a fluid monolayer phase. Assuming values of the polarizability tensor from the literature and that the monolayer fluid has the same areal density as that inferred for the coexisting clusters, we calculate an optical thickness of the fluid pentane layers in reasonable agreement with that measured by ellipsometry. We discuss how these results support the previously proposed "footprint reduction" mechanism of alkane monolayer melting. In the hypercritical regime, we show that the layering behavior is consistent with the two-dimensional Ising model and determine the critical temperatures for layers n = 2-5.

Journal Article↗
PubMed1999

Reversible alterations in brain metabolites during therapy for disseminated nocardiosis using proton magnetic resonance spectroscopy.

We report reversible abnormalities in magnetic resonance spectra acquired from a patient with AIDS undergoing antibiotic and corticosteroid therapy for disseminated nocardiosis, a rare opportunistic infection of immunosuppressed patients which can cause cerebral abscess formation. There was no clinical, CT or MRI evidence of HIV-1 encephalitis. MR spectra were acquired before and after treatment using a two-dimensional chemical shift imaging technique (TR 1500ms, TE 130ms). Prior to treatment, a rise in the choline to creatine ratio and a reduction in the N-acetylaspartate to creatine ratio were observed in MR spectra localized to areas of the left anteromedial centrum semiovale that appeared normal on MR imaging. After 16 weeks, the patient had recovered with complete resolution of the cerebral abscesses on MRI. The MR spectral abnormalities also returned to normal. Two months later, the patient had a relapse with focal neurological signs and further abscesses were demonstrated on MRI of the brain. The patient subsequently died and histopathological and microbiological findings at autopsy confirmed the clinical picture of a recurrence of cerebral nocardiosis with no evidence of HIV-1 encephalitis. This case illustrates reversible MR-measurable metabolite changes in the brain of an HIV-seropositive patient without HIV-1 encephalitis who underwent treatment for cerebral nocardiosis.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

The accessible surface area and stability of oligomeric proteins.

Protein structures are stabilized by hydrophobic and van der Waals forces, and by hydrogen bonds. The relation between these thermodynamic quantities and the actual three-dimensional structure of proteins can not be calculated precisely. However, certain empirical relations have been discovered. Hydrophobic energy is gained by the reduction of surface in contact with water. For monomeric proteins, the area of the surface accessible to solvent, and of that buried in the interior, is a simple function of molecular weight. Proteins with different shapes and secondary structures, but of the same molecular weight, have the same accessible surface area. It has been argued that there is no similar relationship for large oligomeric proteins. In this paper we show that the surface areas of oligomeric proteins, and the areas of the surface buried within them, are directly related to relative molecular mass. Although oligomers of the same molecular weight bury the same amounts of surface, the proportions buried within and between subunits vary. This has important implications for the role of subunit interfaces in the stability and activity of oligomeric proteins.

Chemical Phenomena↗
PubMedDate not supplied

Although it is rapidly metabolized in cultured rat hepatocytes, lauric acid is used for protein acylation.

This study was designed to examine the metabolic fate of exogenous lauric acid in cultured rat hepatocytes, in terms of both lipid metabolism and acylation of proteins. Radiolabeled [14C]-lauric acid at 0.1 mM in the culture medium was rapidly taken up by the cells (94.8 +/- 2.2% of the initial radioactivity was cleared from the medium after a 4 h incubation) but its incorporation into cellular lipids was low (24.6 +/- 4.2% of initial radioactivity after 4 h), due to the high beta-oxidation of lauric acid in hepatocytes (38.7 +/- 4.4% after the same time). Among cellular lipids, lauric acid was preferentially incorporated into triglycerides (10.6 +/- 4.6% of initial radioactivity after 4 h). Lauric acid was also rapidly converted to palmitic acid by two successive elongations. Protein acylation was detected after metabolic labeling of the cells with [11,12-3H]-lauric acid. Two-dimensional electrophoresis separation of the cellular proteins and autoradiography evidenced the incorporation of radioactivity into 35 well-resolved proteins. Radiolabeling of several proteins resulted from covalent linkage to the precursor [11,12-3H]-lauric acid or to its elongation product, myristic acid. The covalent linkages between these proteins and lauric acid were broken by base hydrolysis, indicating that the linkage was of the thioester or ester-type. Endogenous myristic acid produced by lauric acid elongation was used for both protein N-myristoylation and protein S-acylation. Therefore, these results show for the first time that, although it is rapidly metabolized in hepatocytes, exogenous lauric acid is a substrate for the acylation of liver proteins.

Acylation↗
PubMed2003

RNA binding activity of the ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit from Chlamydomonas reinhardtii.

Transfer of the green algae Chlamydomonas reinhardtii from low light to high light generated an oxidative stress that led to a dramatic arrest in the synthesis of the large subunit (LSU) of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). The translational arrest correlated with transient changes in the intracellular levels of reactive oxygen species and with shifting the glutathione pool toward its oxidized form (Irihimovitch, V., and Shapira, M. (2000) J. Biol. Chem. 275, 16289-16295). Here we examined how the redox potential of glutathione affected the RNA-protein interactions with the 5'-untranslated region of rbcL. This RNA region specifically binds a group of proteins with molecular masses of 81, 62, 51, and 47 kDa in UV-cross-linking experiments under reducing conditions. Binding of these proteins was interrupted by exposure to oxidizing conditions (GSSG), and a new protein of 55 kDa was shown to interact with the RNA. The 55-kDa protein comigrated with Rubisco LSU in one- and two-dimensional gels, and its RNA binding activity was further verified by using the purified protein in UV-cross-linking experiments under oxidizing conditions. However, the LSU of purified and oxidized Rubisco bound to RNA in a sequence-independent manner. A remarkable structural similarity was found between the amino-terminal domain of Rubisco LSU in C. reinhardtii and the RNA binding domain, a highly prevailing motif among RNA-binding proteins. It appears from the crystal structure of Rubisco that the amino terminus of LSU is buried within the holoenzyme. We propose that under oxidizing conditions it is exposed to the surface and can, therefore, bind RNA. Accordingly, a recombinant form of the polypeptide domain that corresponds to the amino terminus of LSU was found to bind RNA in vitro with or without GSSG.

5' Untranslated Regions↗
PubMed2006

Neural network-based analysis of thiol proteomics data in identifying potential selenium targets.

Generation of a monomethylated selenium metabolite is critical for the anticancer activity of selenium. Because of its strong nucleophilicity, the metabolite can react directly with protein thiols to cause redox modification. Here, we report a neural network-based analysis to identify potential selenium targets. A reactive thiol specific reagent, BIAM, was used to monitor thiol proteome changes on 2D gel. We constructed a dynamic model and evaluated the relative importance of proteins mediating the cellular responses to selenium. Information from this study will provide new clues to unravel mechanisms of anticancer action of selenium. High impact selenium targets could also serve as biomarkers to gauge the efficacy of selenium chemoprevention.

Antineoplastic Agents↗
PubMed2006

Analysis of protein redox modification by hypoxia.

We examined hypoxia-induced changes in global thiol proteome profile in human prostate cancer cells using a BIAM-based display method. We analyzed the kinetics of protein thiol modification by using a pattern recognition algorithm, self-organizing maps (SOM) clustering, and identified the BIAM-labeled proteins by MALDI-TOF and ESI-tandem mass spectrometry. We found 99 out of 215 of total BIAM-labeled proteins were affected by hypoxia treatment and, yet, with diverse patterns and kinetics of redox modification. Our study proved that proteomics analysis employing the BIAM-labeling method can provide valuable information pertaining to global changes in the redox status of proteins in response to hypoxia.

Apoptosis↗
PubMed2002

Partial least squares proportional hazard regression for application to DNA microarray survival data.

MOTIVATION: Microarrays are increasingly used in cancer research. When gene transcription data from microarray experiments also contains patient survival information, it is often of interest to predict the survival times based on the gene expression. In this paper we consider the well-known proportional hazard (PH) regression model for survival analysis. Ordinarily, the PH model is used with a few covariates and many observations (subjects). We consider here the case that the number of covariates, p, exceeds the number of samples, N, a setting typical of gene expression data from DNA microarrays. RESULTS: For a given vector of response values which are survival times and p gene expressions (covariates) we examine the problem of how to predict the survival probabilities, when N << p. The approach taken to cope with the high dimensionality is to reduce the dimension using partial least squares with the response variable as the vector of survival times. After dimension reduction, the extracted PLS gene components are then used as covariates in a PH regression to predict the survival probabilities. We demonstrate the use of the methodology on two cDNA gene expression data sets, both containing survival data. The first data set contains 40 diffuse large B-cell lymphoma (DLBCL) tissue samples and the second data set contains 49 tissue samples from patients with locally advanced breast cancer in a prospective study.

Breast Neoplasms↗
PubMed1997

Coronary artery disease--diagnosis of ischaemia: general considerations.

Stress echocardiography is a well established tool for the diagnosis of coronary artery disease. It combines the provocation of myocardial ischaemia (either dynamic or nondynamic) with images of the left ventricle obtained by two-dimensional echocardiography. Different modalities can be used to unmask coronary artery disease: increase of myocardial oxygen demand (exercise, pacing, or dobutamine) or reduction in oxygen supply (dipyridamole). Each form of stress has its distinct characteristics such as haemodynamic changes, accuracy, feasibility, and adverse effect, which specifically influence the decision ¿which test for which patient'. Before engaging in the task of performing stress echocardiography, the cardiologist must have undergone special training under the supervision of an experienced stress echocardiographer, followed by an individual learning curve of ¿try out' studies without any diagnostic impact. While performing a stress echocardiographic examination one must always keep the history and risk profile of the individual patient in mind. These factors influence the pre-test likelihood of a patient having coronary artery disease, and therefore also the diagnostic merit of a stress test. While stress echocardiography is not the first test to be employed in patients with suspected coronary artery disease, it represents a diagnostic tool which, if used correctly, is likely to become the most important non-invasive technique in modern cardiology.

Contrast Media↗
PubMed1998

The role of site-specific N-glycosylation in secretion of soluble forms of rabies virus glycoprotein.

Rabies virus glycoprotein is important in the biology and pathogenesis of neurotropic rabies virus infection. This transmembrane glycoprotein is the only viral protein on the surface of virus particles, is the viral attachment protein that facilitates virus uptake by the infected cell, and is the target of the host humoral immune response to infection. The extracellular domain of this glycoprotein has N-glycosylation sequons at Asn37, Asn247, and Asn319. Appropriate glycosylation of these sequons is important in the expression of the glycoprotein. Soluble forms of rabies virus glycoprotein were constructed by insertion of a stop codon just external to the transmembrane domain. Using site-directed mutagenesis and expression in transfected eukaryotic cells, it was possible to compare the effects of site-specific glycosylation on the cell-surface expression and secretion of transmembrane and soluble forms, respectively, of the same glycoprotein. These studies yielded the surprising finding that although any of the three sequons permitted cell surface expression of full-length rabies virus glycoprotein, only the N-glycan at Asn319 permitted secretion of soluble rabies virus glycoprotein. Despite its biological and medical importance, it has not yet been possible to determine the crystal structure of the full-length transmembrane form of rabies virus glycoprotein which contains heterogeneous oligosaccharides. The current studies demonstrate that a soluble form of rabies virus glycoprotein containing only one sequon at Asn319 is efficiently secreted in the presence of the N-glycan processing inhibitor 1-deoxymannojirimycin. Thus, it is possible to purify a conformationally relevant form of rabies virus glycoprotein that contains only one N-glycan with a substantial reduction in its microheterogeneity. This form of the glycoprotein may be particularly useful for future studies aimed at elucidating the three-dimensional structure of this important glycoprotein.

Animals↗
PubMed1997

Does prostaglandin E1 infusion affect the left ventricular filling pattern of end-stage dilated cardiomyopathy? A combined hemodynamic-echo Doppler study.

Prostaglandin E1 improves hemodynamics in patients with severe dilated cardiomyopathy and pulmonary hypertension through it's reducing action on pulmonary resistances. However, few data are available to indicate whether these beneficial effects on right heart hemodynamics translate into any improvement of the altered left ventricular filling pattern that characterizes this condition. We studied 12 patients with dilated cardiomyopathy during preoperative evaluation for cardiac transplantation before and after prostaglandin E1, 30-50 ng/kg/min i.v. Patients underwent catheterization of the right heart and left ventricle by Swan-Ganz catheter, giving simultaneous assessment of pressure by micromanometer and of volume derived from two-dimensional echo-guided Doppler mitral flow velocity, where volume equals mitral velocity integral x valvular area. Prostaglandin E1 induced a significant reduction in mean pulmonary (from 38 to 30 mm Hg; p = 0.0001) and aortic (from 79 to 75 mm Hg, p = 0.05) pressures but no change in heart rate or tau. Peak A wave increased from 28 to 33 cm/s (p = 0.02), along with a reduction in end-diastolic pressure from 29 to 26 mm Hg (p < 0.04), whereas peak E wave did not change. E/A ratio decreased slightly (from 2.5 to 2.1; p < 0.0007) but did not reverse. Systolic volumes decreased (from 231 to 212 ml; p < 0.05), and cardiac index increased from 2.1 to 2.6 L/min/m2 (p = 0.0002) because of a reduction in pulmonary and systemic vascular resistances. The diastolic pressure-volume relation shifted downward along the same curve. Prostaglandin E1 infusion in patients with severe dilated cardiomyopathy and pulmonary hypertension reduces pulmonary and systemic resistances without affecting heart rate, relaxation, or passive diastolic left ventricular properties. Systolic right and left ventricular unloading increases cardiac index, facilitating ventricular emptying. E/A ratio does not reverse, although it decreases slightly, with mechanisms, however, that appear independent of any direct effect of the drug on the ventricular diastolic properties.

Alprostadil↗
PubMed1987

Biochemical and histochemical characterization of cultured rat and hamster pancreatic ducts.

Pancreatic duct fragments were isolated from rat and hamster pancreas and were cultured in an agarose matrix for up to 8 weeks (rat) or 20 weeks (hamster). The fragments consisted predominantly of duct epithelium, lesser numbers of stromal and atrophied acinar cells, and small numbers of islet cells. Hamster ducts averaged 3 micrograms protein per duct while rat ducts averaged 1 microgram, and the protein:DNA ratio of both types of ducts was less than that of whole pancreas. Estimated average duct yields of 6% (hamster) and 1% (rat) were based on the protein content of the ducts. Duct viability was shown by the incorporation of 3H-thymidine and 3H-leucine into bulk DNA and protein and by autoradiography. gamma-Glutamyl transferase and (Na + K)-ATPase specific activities were slightly elevated while amylase was depressed in the ducts when compared with whole pancreas in both species. gamma-Glutamyl transferase was localized histochemically in both duct epithelium and in surviving acinar tissue, as seen in vivo. Amylase was shown by immunohistochemistry to be present within duct lumina and in atrophied acini and their lumina. Alkaline phosphatase and Mg-ATPase specific activities were elevated in the hamster, but reduced in the rat, when compared with whole pancreas. Hamster alkaline phosphatase and Mg-ATPase were localized by histochemistry to the duct stroma, where these enzymes are not detected in vivo. Carbonic anhydrase was found in the duct epithelium of both species, as in vivo, as well as in the duct stroma, unlike in vivo. Acid glycosaminoglycans, as revealed by alcian blue staining, were found at the apical surfaces and in the lumina of both kinds of ducts. Glutathione-S-transferase and glucose-6-phosphate dehydrogenase were elevated in rat ducts, but not in hamster ducts. The polypeptide compositions of cultured ducts, freshly isolated pancreatic islets, and whole pancreas were compared by one-dimensional sodium dodecyl sulfate polyacrylamide gradient gel electrophoresis. No duct-specific polypeptides were observed; the ducts were characterized mainly by the reduction or absence of polypeptides, including some zymogens, seen in whole pancreas.

Alkaline Phosphatase↗
PubMed2000

Feldkamp-type cone-beam tomography in the wavelet framework.

X-ray computed tomography (CT) is in transition from fan-beam to cone-beam geometry. For cone-beam volumetric imaging, reduction of radiation exposure remains an important issue. Because the wavelet approach was shown to be effective and flexible for two-dimensional (2-D) local region reconstruction, we are motivated to perform wavelet local CT in cone-beam geometry. In this paper, we formulate the Feldkamp cone-beam reconstruction from the wavelet perspective, derive both full-scan and half-scan Feldkamp-type formulas for either global or local reconstruction, and demonstrate the feasibility and utility in synthetic and real data. It is found that using the wavelet Feldkamp approach, a three-dimensional (3-D) region of interest (ROI) can be reconstructed with neither severe image artifacts nor any significant constant bias in our simulation and experiments.

Animals↗