Involvement of water molecules in the association of monoclonal antibody HyHEL-5 with bobwhite quail lysozyme.

Fluorescence polarization spectroscopy and isothermal titration calorimetry were used to study the influence of osmolytes on the association of the anti-hen egg lysozyme (HEL) monoclonal antibody HyHEL-5 with bobwhite quail lysozyme (BWQL). BWQL is an avian species variant with an Arg-->Lys mutation in the HyHEL-5 epitope, as well as three other mutations outside the HyHEL-5 structural epitope. This mutation decreases the equilibrium association constant of HyHEL-5 for BWQL by over 1000-fold as compared to HEL.

Association of the anti-hen egg lysozyme antibody HyHEL-5 with avian species variant and mutant lysozymes.

The energetics of association of the murine anti-hen egg lysozyme antibody HyHEL-5 with bobwhite quail lysozyme, California quail lysozyme, and the Arg45-->Lys mutant of hen egg lysozyme was characterized by isothermal titration calorimetry. The association of each lysozyme with HyHEL-5 is enthalpically driven in the temperature range 10 degrees C to 37 degrees C. The calorimetric results indicate that the salt-links between Arg45 and Arg68 of hen egg lysozyme and GluH50 on the HyHEL-5 paratope are energetically important in HyHEL-5/HEL association.

Free radical reactions involving the angiotensin converting enzyme inhibitor captopril.

Using the pulse radiolysis technique, absolute rate constants have been obtained for the reaction of captopril with several free radicals. The results demonstrate that although captopril reacts rapidly with a number of free radicals, such as the hydroxyl radical (k = 5.1 × 10(9) dm(-3)mol(-1)s(-1)) and the thiocyanate radical anion (k = 1.

Mesenteric vein thrombosis. Four cases and review of the literature.

Mesenteric vein thrombosis, an uncommon but important clinical entity, can cause ischemia or infarction of the small intestine. Mesenteric vein thrombosis was first described nearly a century ago, but diagnosis remains difficult because it can affect young individuals without any known predisposing disorder and because patients often present with nonspecific abdominal symptoms. We report 4 cases of small intestinal ischemia secondary to superior mesenteric vein thrombosis.

Body dysmorphic disorder: a cognitive behavioural model and pilot randomised controlled trial.

A cognitive behavioural model of body image is presented with specific reference to body dysmorphic disorder (BDD). We make specific hypotheses from the model for testing BDD patients in comparison with: (i) patients with "real" disfigurements who seek cosmetic surgery; (ii) subjects with "real" disfigurements who are emotionally well adjusted; and (iii) healthy controls without any defect. There have been no randomised controlled trials of treatment for BDD and therefore the model has clear implications for the development of cognitive behavioural therapy.

Refined structures of bobwhite quail lysozyme uncomplexed and complexed with the HyHEL-5 Fab fragment.

The HyHEL-5 antibody has more than a thousandfold lower affinity for bobwhite quail lysozyme (BWQL) than for hen egg-white lysozyme (HEL). Four sequence differences exist between BWQL and HEL, of which only one is involved in the interface with the Fab. The structure of bobwhite quail lysozyme has been determined in the uncomplexed state in two different crystal forms and in the complexed state with HyHEL-5, an antihen egg-white lysozyme Fab.

Body dysmorphic disorder. A survey of fifty cases.

Background: Body dysmorphic disorder (BDD) consists of a preoccupation with an 'imagined' defect in appearance which causes significant distress or impairment in functioning. There has been little previous research into BDD. This study replicates a survey from the USA in a UK population and evaluates specific measures of BDD.

Scavenging of nitrogen dioxide, thiyl, and sulfonyl free radicals by the nutritional antioxidant beta-carotene.

Mechanisms of free radical scavenging by the nutritional antioxidant beta-carotene have been investigated by pulse radiolysis. Free radicals, which can initiate the chain of lipid peroxidation, including nitrogen dioxide (NO2.), thiyl (RS.

Microcalorimetric characterization of the anion-exchange adsorption of recombinant cytochrome b5 and its surface-charge mutants.

The adsorption of recombinant soluble tryptic fragment of rat cytochrome b5 on the strong anion exchanger Mono Q was studied using isothermal titration calorimetry and differential scanning calorimetry (DSC). Titration calorimetry results obtained at low levels of adsorbed protein show increasingly endothermic (unfavorable) enthalpies of binding with increasing surface coverage, confirming the heterogeneous nature of binding. The enthalpy of adsorption declines toward zero at higher loadings.

Determination of the pKa values of titratable groups of an antigen-antibody complex, HyHEL-5-hen egg lysozyme.

The titration behavior of the ionizable residues of the HyHEL-5-hen egg lysozyme complex and its individual components has been studied using continuum electrostatic calculations. Several residues of HyHEL-5 had pKa values shifted away from model values for isolated residues by more than three pH units. Shifts away from the model values were smaller for the residues of hen egg lysozyme.

Hepatitis C virus associated membranous glomerulonephritis.

Hepatitis C virus infection has been associated with a variety of extrahepatic disorders. We report four patients with membranous glomerulonephritis and hepatitis C virus infection. In contrast to patients previously reported with HCV infection and membranoproliferative glomerulonephritis, these patients have normal or minimally reduced complement levels and no evidence of rheumatoid factor or cryoglobulinemia.

Assessment of hepatitis C viremia using molecular amplification technologies: correlations and clinical implications.

Objective: To compare two recently developed molecular techniques for quantitating the levels of hepatitis C virus (HCV) RNA in the serum of patients with a wide spectrum of chronic hepatitis C.

Design: Serum samples from 299 patients with HCV viremia, 101 control patients without HCV infection, and 19 consecutive patients receiving systemic interferon therapy were evaluated by a commercially available branched-chain DNA (bDNA) assay and a quantitative competitive polymerase chain reaction (PCR).

Setting: University-based hepatology clinics and reference virology laboratory.

Free energy simulations of the HyHEL-10/HEL antibody-antigen complex.

Free energy simulations are reported for the N31LD mutation, both in the HyHEL-10-HEL antibody-lysozyme complex and in the unliganded antibody, using the thermodynamic-cycle perturbation method. The present study suggests that the mutation would change the free energy of binding of the complex by -5.6 kcal/mol (unrestrained free energy simulations), by -0.

Hepatitis C virus-associated glomerulonephritis.

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease and is associated with a variety of extrahepatic manifestations, including cryoglobulinemia and glomerulonephritis. Epidemiologic evidence suggests that HCV infection may be a major risk factor for both cryoglobulinemic and type I membranoproliferative glomerulonephritis (MPGN). Clinical symptoms and laboratory data may or may not reflect the presence of chronic liver disease.

Human immunodeficiency virus 1-associated necrotizing cholangitis caused by infection with Septata intestinalis.

A 30-year-old man with acquired immunodeficiency syndrome developed human immunodeficiency virus 1-related cholangiopathy with atypical radiographic features showing extensive hepatobiliary involvement. Extended clinical evaluation, including endoscopic retrograde cholangiopancreatography, and the results of both ultrasonic- and computed tomographic-guided liver biopsies failed to provide a diagnosis. A laparoscopic needle biopsy of a single 3-cm, firm, tan lesion on the anterior surface of the liver showed severe necrotizing cholangitis.

Hepatitis C virus-associated glomerulonephritis. Effect of alpha-interferon therapy.

Hepatitis C virus (HCV) infection may present as a primary glomerular disease. We report 34 adult patients who presented with proteinuria and had circulating anti-HCV antibodies. Primary risk factors included a history of intravenous drug abuse (56%) or blood transfusion (18%).

Presence of a preferred anion-exchange binding site on cytochrome b5: structural and thermodynamic considerations.

A preferred chromatographic contact region for adsorption of recombinant soluble tryptic fragment of rat cytochrome b5 on the hydrophilic anion-exchanger Mono Q has been identified using conservative carboxylate-to-amide mutations of charged residues. Equilibrium adsorption isotherms were measured under conditions of full reversibility by high ionic strength, as confirmed by explicit mass balances performed for each experiment. Although cytochrome b5 displays several clusters of negative charge, mutations in one cluster consistently reduce binding affinity and the stoichiometric displacement parameter Z by much greater factors than do mutations in other areas of the molecule.

Improving protein extraction yield in reversed micellar systems through surface charge engineering.

The mechanism of extraction of rat cytochrome b(5) from water into a sodium dioctylsulfosuccinate (AOT) micellar organic phase was studied using protein engineering of surface charged residues. The extraction behavior of native cytochrome b(5) and modified proteins with substitutions of the type glutamic acid --> lysine at positions 44 (E44K), 56 (E56K), and 92 (E92K), was studied as a function of pH. The results indicate that an important mechanism of extraction is an electrostatic interaction of this protein with the negatively charged surfactant.