The natural history of renal disease in Australian Aborigines. Part 2. Albuminuria predicts natural death and renal failure.

BACKGROUND: The purpose of this study was to describe the relationship of albuminuria and glomerular filtration rate (GFR) with natural death and renal failure in an Australian Aboriginal community with high rates of renal disease. METHODS: Study subjects were 825 adults (18+ years, mean 33.6 years) or 88% of adults in a remote community who participated in a health screening program offered between 1990 and 1997. The urinary albumin:creatinine ratio (ACR; g/mol) was used as the renal disease marker. Participants were followed for 1.0 to 9.8 years (mean 5.8 years) until renal failure, death, the start of systematic antihypertensive/renal-protective treatment or June 30, 2000. RESULTS: Sixty-five people reached a terminal end point of renal failure or natural death. Sixteen people developed terminal renal failure, all of whom had an ACR of 34+ at baseline exam. There were 49 other natural deaths, which were also strongly correlated with increasing ACR and decreasing GFR over a wide range. This was observed in people without diabetes and in people with normal and elevated blood pressures. It applied to deaths associated with cardiovascular disease and to deaths without an assigned primary or underlying cardiovascular or renal cause. With adjustment for age, the association with death was more robust with ACR than GFR. When compared with people with an ACR <3.4, the hazard ratio (HR; 95% CI) for nonrenal natural death of persons with an ACR 3.4 to 33 was 3.0 (1.1 to 8.4), with an ACR 34 to 99, it was 5.4 (1.8 to 15.9), and with an ACR 100+, it was 6.5 (2.0 to 21). Regression equations predicted that each tenfold increase in the ACR was associated with a 3.7-fold increase in all-cause natural death: a> 400-fold increase in renal deaths, a 4-fold increase in cardiovascular deaths, and a 2.2-fold increase in nonrenal noncardiovascular deaths. Eighty-four percent of all-cause natural death was associated with pathologic albuminuria. CONCLUSION: All renal failure develops out of a background of persistent albuminuria in this population. More important, albuminuria and, inversely, GFR are powerful markers of risk for nonrenal natural death, including, but not restricted to, cardiovascular deaths. Most of the risk for premature death can be assessed by a simple urine test, and interventions that prevent development and progression of albuminuria and loss of GFR should not only prevent renal insufficiency, but powerfully reduce mortality from natural causes as well.

Association and dissociation kinetics of bobwhite quail lysozyme with monoclonal antibody HyHEL-5.

The anti-hen egg lysozyme monoclonal antibody HyHEL-5 and its complexes with various species-variant and mutant lysozymes have been the subject of considerable experimental and theoretical investigation. The affinity of HyHEL-5 for bobwhite quail lysozyme (BWQL) is over 1000-fold lower than its affinity for the original antigen, hen egg lysozyme (HEL). This difference is believed to arise almost entirely from the replacement in BWQL of the structural and energetic epitope residue Arg68 by lysine. In this study, the association and dissociation kinetics of BWQL with HyHEL-5 were investigated under a variety of conditions and compared with previous results for HEL. HyHEL-5-BWQL association follows a bimolecular mechanism and the dissociation of the antibody-antigen complex is a first-order process. Changes in ionic strength (from 27 to 500 mM) and pH (from 6.0 to 10.0) produced about a 2-fold change in the association and dissociation rates. The effect of viscosity modifiers on the association reaction was also studied. The large difference in the HEL and BWQL affinities for HyHEL-5 is essentially due to differences in the dissociation rate constant.

Characterization of interactions between the anti-apoptotic protein BAG-1 and Hsc70 molecular chaperones.

The anti-cell death protein BAG-1 binds to 70-kDa heat shock proteins (Hsp70/Hsc70) and modulates their chaperone activity. Among other facilitory roles, BAG-1 may serve as a nucleotide exchange factor for Hsp70/Hsc70 family proteins and thus represents the first example of a eukaryotic homologue of the bacterial co-chaperone GrpE. In this study, the interactions between BAG-1 and Hsc70 are characterized and compared with the analogous GrpE-DnaK bacterial system. In contrast to GrpE, which binds DnaK as a dimer, BAG-1 binds to Hsc70 as a monomer with a 1:1 stoichiometry. Dynamic light scattering, sedimentation equilibrium, and circular dichroism measurements provided evidence that BAG-1 exists as an elongated, highly helical monomer in solution. Isothermal titration microcalorimetry was used to determine the complex stoichiometry and an equilibrium dissociation constant, KD, of 100 nM. Kinetic analysis using surface plasmon resonance yielded a KD consistent with the calorimetrically determined value. Molecular modeling permitted a comparison of structural features between the functionally homologous BAG-1 and GrpE proteins. These data were used to propose a mechanism for BAG-1 in the regulation of Hsp70/Hsc70 chaperone activity.

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. A moderate variation in the pKa values of the titratable groups was observed upon increase of the ionic strength from 0 to 100 mM, amounting to 1-2 pH units in most cases. Under physiological conditions, the net charge of HyHEL-5 was opposite that for hen egg lysozyme. Several residues, including those involved in the Arg-Glu salt bridges that have been proposed to be important in antibody-antigen binding, had pKa values that were changed significantly upon binding. The main titration event upon antibody-antigen binding appears to be loss of a proton from residue GluH50 of the Fv molecule. The limitations of our calculation methods and the role they might play in the design of antibodies for use in assays, sensors and separations are discussed.

The efficacy of prophylactic ondansetron, droperidol, perphenazine, and metoclopramide in the prevention of nausea and vomiting after major gynecologic surgery.

The prophylactic antiemetic efficacy of intravenous (i.v.) ondansetron, droperidol, perphenazine, and metoclopramide was evaluated in a prospective, double-blind study of 360 ASA physical status I-III patients undergoing total abdominal hysterectomy (TAH). Subjects were randomized to receive i.v., one of ondansetron 4 mg, droperidol 1.25 mg, perphenazine 5 mg, metoclopramide 10 mg, or placebo prior to induction of anesthesia. Hypotension immediately after administration of metoclopramide was observed in two patients and four patients given ondansetron developed profound systolic hypotension at induction of anesthesia. Twenty-two percent of patients receiving droperidol became sedated. Postoperatively, patients developing severe nausea, retching, or vomiting, defined as severe emetic sequelae (SES), were deemed to have failed antiemetic prophylaxis and received antiemetic rescue. A significantly larger number of patients who received i.v. ondansetron (63%), droperidol (76%), and perphenazine (70%) were free of SES when compared to placebo (43%); P < 0.05. Metoclopramide was ineffective. Although ondansetron, droperidol, and perphenazine were effective in providing antiemetic prophylaxis, only i.v. perphenazine was free of side effects. Hence, we conclude that perphenazine is the best choice for antiemetic prophylaxis after TAH.

The Manitoba Nutrition Survey: fat consumption data.

A nutrition survey was conducted as part of a larger cardiovascular risk study undertaken by the Manitoba Heart Health Project. A representative group of Manitobans participated in the study, 68% of whom reported their food intake using a food frequency questionnaire. After verifying and merging data from the nutrition and risk factor questionnaires used in the survey, 2,115 were used in data analysis. Results are reported by gender for three age groups. The proportion of food energy derived from total fat varied between 35.3% for senior females and 40.2% for young males. Food of seniors contained a lower proportion of energy from fat than that of either of the two younger age groups. In all three age groups, men consumed diets with a higher proportion of fat than did women. People in regional centres and rural areas obtained higher proportions of energy from fat than did people in Winnipeg. Fat intake from butter, margarine or spreads eaten with bread and potatoes was high compared to the intake from other foods.

Molecular dynamics simulations of a winter flounder "antifreeze" polypeptide in aqueous solution.

A winter flounder antifreeze polypeptide (HPLC-6) has been studied in vacuo and in aqueous solution using molecular dynamics computer simulation techniques. The helical conformation of this polypeptide was found to be stable both in vacuum and in solution. The major stabilizing interactions were found to be the main-chain hydrogen bonds, a salt-bridge interaction, and solute-solvent hydrogen bonds. A significant bending in the middle of the polypeptide chain was observed both in vacuo and in solvent at 300 K. Possible causes of the bending are discussed. From simulations of mutant polypeptide molecules in vacuo, it is concluded that the bend in the native polypeptide was caused by side chain to backbone hydrogen bond competition involving the Thr 24 side chain and facilitated by strains on the helix resulting from the Lys 18-Glu 22 salt bridge.

Influence of temperature on the growth of Bordetella avium in turkeys and in vitro.

Effects of temperature on growth of three strains of Bordetella avium were determined in young turkeys and in vitro. Colonization of the tracheal mucosa by two virulent strains of B. avium was significantly greater in cold-stressed turkeys than in heat-stressed turkeys. The avirulent vaccine strain, ART-VAX, colonized tracheas of cold-stressed turkeys to a limited extent but failed to colonize heat-stressed turkeys. Growth rates of the three B. avium strains were determined in brain-heart infusion broth at 30, 35, 40, and 45 C. All three strains grew best at 35 C but were killed by 45 C. Compared with virulent strains, ART-VAX grew markedly less at all temperatures, and most cultures of ART-VAX grew at 40 C only after a variable period of declining numbers of viable bacteria. This study indicates that temperature affects growth of B. avium in vivo and in vitro and that growth of the ART-VAX strain is fundamentally different from growth of virulent strains.

The failure of trichothecene mycotoxins and whole cultures of Fusarium tricinctum to cause experimental haemorrhagic syndromes in calves and pigs.

Piglets and calves were dosed orally with pure diacetoxyscirpenol (DAS) and T-2 toxin, crude extracts of Fusarium tricinctum containing T-2 toxin, and whole cultures of F tricinctum containing T-2 toxin at a constant daily rate of 0.1 mg toxin per kg body-weight (piglets) or 0.2 mg toxin per kg body-weight (calves). The treatment continued for periods of seven to 78 days but it failed to induce clinical haemorrhagic syndromes. Increasing the dose of F tricinctum culture five-fold for eight days following 78 days at the lower dose was equally ineffective. The lack of an effect by daily intakes of toxin that could have been ingested with naturally contaminated feedstuffs suggests that DAS, T-2 toxin and other metabolites of F tricinctum probably have little or no part to play in the aetiology of feed associated haemorrhagic disease.