Osteocytic connexin 43 is not required for the increase in bone mass induced by intermittent PTH administration in male mice.

OBJECTIVE: To investigate whether osteocytic connexin 43 (Cx43) is required for the bone response to intermittent PTH administration, and whether the connexin is involved in maintaining the bone matrix. METHODS: Human PTH(1-34) was injected to adult male mice expressing (Cx43(fl/fl)) or not osteocytic Cx43 (Cx43(fl/fl);DMP1-8kb-Cre) daily (100 µg/kg/d) for 14 days. RESULTS: Cx43(fl/fl);DMP1-8kb-Cre mice have no difference in body weight and BMD from 1 to 4 months of age. Intermittent PTH administration increased BMD and BV/TV and induced a similar increase in type I collagen, alkaline phosphatase, runx2, osteocalcin, and bone sialoprotein expression in mice from both genotypes. On the other hand, osteocytic deletion of Cx43 did not alter mRNA levels of glycosaminoglycans, proteoglycans, collagens and osteoblast-related genes. In addition, expression of collagens assessed by immunohistochemistry was not affected by deleting osteocytic Cx43. However, PTH administration increased type II collagen only in Cx43(fl/fl) control mice, whereas hormone increased type I collagen expression only in Cx43(fl/fl);DMP1-8kb-Cre mice. Furthermore, PTH increased maturity of collagen fibers in control, but not in Cx43-deficient mice. CONCLUSION: Expression of Cx43 in osteocytes is dispensable for bone anabolism induced by intermittent PTH administration; but it can modulate, at least in part, the effect of PTH on the bone matrix environment.

Population pharmacokinetics of ustekinumab in patients with active psoriatic arthritis.

PURPOSE: To characterize the population pharmacokinetics of subcutaneous ustekinumab, a human IgG1Kappa; monoclonal antibody against interleukin-12/23p40, using data from a randomized, double-blind, placebo-controlled Phase II study in patients with active psoriatic arthritis (PsA). METHODS: A total of 786 quantifiable serum ustekinumab concentrations from 130 patients were analyzed using a nonlinear mixed-effects modeling approach. A 1-compartment model with first-order absorption and elimination was selected as the structural model. RESULTS: The population typical mean (percent relative standard error (%RSE)) values for apparent clearance (CL/F), apparent volume of distribution (V/F), and absorption rate constant (ka) obtained from the final covariate model were 0.465 l × day-1 (5.1%), 14.3 l (4.4%), and 0.427 day-1 (3.9%), respectively. The between-subject variability in CL/F, V/F, and ka were 53.9%, 42.3%, and 82.4%, respectively. Patient body weight and antibody-to-ustekinumab status were significant covariates affecting the CL/F and/or V/F of ustekinumab. None of the other factors evaluated, such as age, sex, race, baseline disease characteristics, concomitant methotrexate or nonsteroidal anti-inflammatory drugs, and past use of immunosuppressives, biologics, systemic corticosteroids, or disease-modifying antirheumatic drugs, were found to have significant effects on the pharmacokinetics of ustekinumab. CONCLUSION: The pharmacokinetics of ustekinumab in patients with PsA are comparable to those in patients with moderate-to-severe plaque psoriasis which was previously investigated.

Serum albumin concentration: a predictive factor of infliximab pharmacokinetics and clinical response in patients with ulcerative colitis.

OBJECTIVES: Infliximab, an IgG1 monoclonal antibody (mab), has large inter-individual serum concentration variability. The objective was to determine the extent of the association of baseline albumin concentration and infliximab disposition in patient with ulcerative colitis. METHOD: Data from 728 patients with ulcerative colitis from two clinical trials were analyzed to evaluate trends between infliximab pharmacokinetics and serum albumin, or liver or kidney function. Response in the placebo and treated groups were compared by baseline serum albumin concentrations (SAC) groups. RESULTS: Patients with higher SAC maintained higher infliximab concentrations, lower clearance, and longer half-life than patients with lower SAC. When analyzed by SAC quartiles, patients in the highest quartile had several-fold greater trough infliximab concentrations when compared with those in the lowest quartile. These observations were consistent in both studies and at different dose levels. Generally, clinical response in patients did not vary with SAC when the SAC was within the normal range, apparently because serum infliximab concentrations remained at therapeutic levels. However, patients with SAC lower than the normal laboratory reference range had much lower median serum infliximab concentrations and lower response rates compared with patients within normal SAC. Infliximab pharmacokinetics did not correlate with SGOT or creatinine clearance. CONCLUSIONS: It is hypothesized that the common rescue pathway for both albumin and IgG involving the neonatal Fc receptor may be responsible for the relationship between serum albumin and serum infliximab levels. Baseline albumin level may serve as a valuable and convenient measure of mab pharmacokinetic expectations in these patients.

Population pharmacokinetics of golimumab in patients with ankylosing spondylitis: impact of body weight and immunogenicity.

AIMS: To develop a population pharmacokinetic (PK) model of subcutaneously administered golimumab, a human anti-tumor necrosis factor monoclonal antibody, in patients with ankylosing spondylitis (AS), estimate typical fixed and random population PK parameters, and identify significant covariates on golimumab pharmacokinetics. METHODS: Serum concentration data through Week 24 of a randomized, double-blind, placebo-controlled Phase III trial of golimumab (50 or 100 mg every 4 weeks) were analyzed using a nonlinear mixed-effects modeling approach. The effects of potential covariates on golimumab were evaluated. RESULTS: A one-compartment PK model with first-order absorption and elimination was chosen to describe the observed golimumab concentration-time data in patients with AS. Population estimates obtained from the final model for a typical 70-kg patient were: apparent systemic clearance (CL/F), 1.41 l/day (95% confidence interval (CI): 1.31 - 1.51) and apparent volume of distribution (V/F), 22.6 L (95% CI: 20.7 - 24.4). The first-order absorption rate constant (Ka) was estimated to be 1.01 day-1 (95% CI: 0.760 - 1.46). The between-subject variabilities for CL/F, V/F, and Ka were 35.2%, 38.6%, and 78.6%, respectively. Body weight was the most significant covariate, affecting both CL/F and V/F. Antibody-to-golimumab status, baseline C-reactive protein level, and sex were also identified as significant covariates on CL/F. CONCLUSIONS: A one-compartment model with first-order absorption and elimination adequately described the PK of golimumab following subcutaneous administrations in patients with AS. Body weight and anti-golimumab antibody status were found to significantly influence golimumab clearance. When a patient does not respond to the prescribed golimumab therapy, the possibility of the development of antibodies to golimumab has to be considered.

Absolute Bioavailability and Pharmacokinetic Comparability of Sirukumab Following Subcutaneous Administration by a Prefilled Syringe or an Autoinjector.

This phase 1, randomized, open-label study assessed the absolute bioavailability and pharmacokinetic comparability of sirukumab, a human anti-interleukin-6 monoclonal antibody, following subcutaneous (SC) administration via Prefilled Syringe-UltraSafe Passive® Delivery System (PFS-U) or Prefilled Syringe-SmartJect® Autoinjector (PFS-AI; Janssen Research & Development, LLC, Spring House, Pennsylvania). A total of 144 healthy male subjects were randomized to 5 single-dose treatment groups: sirukumab 50 mg and 100 mg (each by PFS-U and PFS-AI) and sirukumab 100 mg intravenous (IV) infusion. Pharmacokinetic parameters were calculated using noncompartmental analysis. Following SC administration, maximum serum concentrations (Cmax ) and area under the concentration-vs-time curve (AUC) increased in an approximately dose-proportional manner. Median time to reach Cmax was 5 days, and mean half-life ranged from 16 to 19 days. Mean absolute bioavailability of sirukumab by PFS-AI and PFS-U, respectively, was estimated at 92.4% and 81.4% with 100 mg and 88.4% and 94.7% with 50 mg. Ratios of geometric means (90% confidence intervals) of Cmax and AUC0-77d for PFS-AI:PFS-U were 1.13 (1.03, 1.25) and 1.14 (1.05, 1.24), respectively, indicating comparable systemic exposures of sirukumab following a single 100-mg SC dose by PFS-U or PFS-AI. The incidence of antibodies to sirukumab was low (1.4%). No new safety concerns associated with sirukumab were identified at either dose.

Characterization of the CA 125 antigen associated with human epithelial ovarian carcinomas.

The murine monoclonal antibody OC125 reacts with an antigenic determinant (CA 125) found on a high-molecular-weight glycoprotein complex present in the serum of greater than 80% of women with epithelial ovarian cancer. The antigen expressing CA 125 (CA 125 antigen) isolated from the sera of ovarian carcinoma patients was shown by gel electrophoresis, molecular size exclusion chromatography, and buoyant density ultracentrifugation to have similar immunological and physical characteristics to antigen isolated from an ovarian cancer cell line (OVCA 433) and human milk. A composite sodium dodecyl sulfate: polyacrylamide:1.0% agarose gel resolved the CA 125 activity from the three sources of antigen into disperse bands of similar electrophoretic mobilities with apparent masses of 200,000 to 1 million daltons. The buoyant densities of the CA 125 antigen complexes from human serum, OVCA 433 cells, and human milk were in the range of 1.36 to 1.46 g/ml. Isolation of CA 125 antigen of higher purity from OVCA 433 supernatant was achieved by a series of steps including OC125 immunoaffinity chromatography. Subsequent resolution of this purified CA 125 antigen complex by sodium dodecyl sulfate:polyacrylamide gel electrophoresis gave rise to a band at approximately 200,000 daltons. Treatment of the CA 125 antigen from OVCA 433 cells with 10 mM periodic acid resulted in no loss of activity. Reduction and alkylation in 6 M guanidine-HCl or treatment at 100 degrees C for 20 min resulted in complete loss of activity. Exoglycosidase treatments did not result in loss of activity, whereas protease digestion eradicated all activity. These data strongly suggest that the CA 125 antigenic determinant is composed of, at least in part, conformationally dependent peptide.

A one-step, competitive electrochemiluminescence-based immunoassay method for the quantification of a fully human anti-TNFalpha antibody in human serum.

A quantitative, one-step, competitive electrochemiluminescence (ECL)-based immunoassay for the determination of a fully human, anti-TNFalpha monoclonal antibody in human serum has been developed. A biotinylated, mouse anti-variable region-specific antibody and a ruthenium-labeled anti-TNFalpha antibody were the only specific reagents needed to develop the assay. A single incubation step of 2 h followed by ECL detection was used. The assay was capable of measuring the analyte in neat serum over approximately a 1600-fold range with higher concentrations measured following a single dilution. Assay accuracy, precision, and reproducibility were suitable to support pharmacokinetic studies of the analyte. This competitive assay format offers an alternative approach to the development of immunoassays for the measurement of macromolecules in complex matrices to support preclinical and clinical studies.

Human anti-mouse immunoglobulins in sera of patients treated chronically with monoclonal antibody-purified factor VIII.

In the process of isolation of factor VIII from human plasma making use of immunoadsorbents prepared by coupling monoclonal murine antibodies to resins, trace amounts of murine immunoglobulin G (IgG) antibodies are released from the resin into the final Monoclate product. This trace contamination, amounting to not more than 50 ng/100 units of Monoclate, was assumed to be below the threshold amounts necessary for inducing an immune response. Nevertheless, we have developed a series of highly sensitive and specific radioimmunoassays for the determination of human antibodies of the IgG, IgM, and IgE classes against the murine monoclonal IgG used for purification of Monoclate. Screening of sera from adults and children treated with Monoclate showed that in no case were any antibodies produced in response to injection of Monoclate. Surprisingly, sera from several patients had a high activity against murine IgG both before and after treatment with Monoclate.

Human granulocyte CD11b expression as a pharmacodynamic biomarker of inflammation.

A method has been developed for the direct quantification of the CD11b integrin on granulocytes by flow cytometric analysis of whole blood specimens following either LTB(4) or lipopolysaccharide (LPS) stimulation. This method has utility in evaluating the pharmacodynamic action of either LTB(4) receptor antagonists or immune cell modulators in effecting CD11b integrin expression and granulocyte activation in human subjects administered such drugs. Previous studies using CD11b as a biomarker of granulocyte activation have faltered because of the difficulty in controlling the activation state of the granulocyte following removal of blood from subjects. The present study has made use of a newly validated method using either LTB(4) or LPS to stimulate CD11b expression on granulocytes and has been used, as one measure, in the evaluation of LPS activity when administered to normal human volunteers.

Lack of immune response to mouse IgG in hemophilia A patients treated chronically with Monoclate, a monoclonal antibody affinity purified factor VIII preparation.

Hemophilia A is caused by factor VIII deficiency that historically has been treated with either a cryoprecipitate fraction of serum or factor VIII concentrate. Recently, the availability of affinity isolated factor VIII (Monoclate) has allowed for a highly purified preparation for the chronic therapy of hemophilia A. This factor VIII preparation contains a trace quantity (less than 50 ng/100 I. U.) of mouse IgG. Immunoassays for the measurement of human IgG, IgM and IgE anti-mouse IgG antibody (HAMA) were developed and used to measure HAMA levels in hemophilia A patients undergoing chronic therapy with Monoclate in three different clinical studies. Natural antibodies to mouse IgG were observed in patient sera prior to Monoclate infusion. Data is presented demonstrating that induction of HAMA upon Monoclate treatment does not occur. The low level of mouse IgG contained in Monoclate appears to be below the threshold of immunogenicity. Most importantly, clinical symptoms related to hypersensitivity or anaphylaxis were never observed in any patient undergoing chronic therapy with Monoclate in these clinical studies.

Effects of raised body temperature on reasoning, memory, and mood.

Volunteers' body core temperatures were raised to 38.80-39.05 degrees C within a few minutes by immersion in water at 41 degrees C. Tests were then made with the subjects insulated and cooling slowly. Control immersions were made in water at 37 degrees C when core temperatures remained at 36.60-37.40 degrees C. Neither memory registration nor recall of memories registered an hour earlier, nor immediate ability to recall digit spans forward or backward was affected by the increase in core temperature. The increase in temperature did not have any significant effect on accuracy of performance of verbal logic problems or of two-digit subtractions. However, the increase in core temperature was associated with a significant increase in the speed of performance of the tests, by 11 and 10%, respectively. The warm immersions also induced a significant decrease in alertness and an increase in irritability as assessed subjectively by the volunteers; control immersions had no such effects.

Morning spot and 24-hour urinary 6 beta-hydroxycortisol to cortisol ratios: intraindividual variability and correlation under basal conditions and conditions of CYP 3A4 induction.

A single spot urine collection to measure the ratio of 6 beta-hydroxycortisol (6 beta-OHC) to free cortisol (C) has been proposed as a research tool for the assessment of CYP3A4 induction. However, intraindividual variability in 6 beta-OHC/C under basal conditions and conditions of induction has not been prospectively evaluated, and findings on the correlation between morning spot and 24-hour urinary ratios have been conflicting. In this study, the variability in morning spot and 24-hour urinary 6 beta-OHC/C ratios was assessed in 15 healthy adult male volunteers before, during, and after oral administration of rifampin 600 mg once daily for 14 days. In addition, the correlation between morning spot and 24-hour urinary ratios measured under baseline, maximum induction, and postinduction was determined. Intraindividual coefficients of variation (CVs) at baseline for the morning spot and 24-hour ratios were 54.3% and 57.1%, respectively, and were not changed significantly during induction. No significant differences were detected in the variability between the morning spot and 24-hour ratios at baseline, maximum induction, or postinduction. A good correlation (r = 0.61, p < 0.0001) was detected between the mean morning spot and 24-hour urinary ratios. Mean (+/- SEM) percent increases in the morning spot and 24-hour ratios at maximum induction relative to baseline were 320% +/- 73% and 137% +/- 30%, respectively (p = 0.019). All 15 subjects had an increase in the mean morning spot ratio at maximum induction relative to baseline, whereas 12 subjects showed an increase in the mean 24-hour ratio. The time course of changes in the mean morning spot urinary ratio in response to a 14-day course of rifampin was also similar to that reported previously in a study using 24-hour urine collections. These findings suggest that measurement of the morning spot urinary 6 beta-OHC/C ratio is an effective and efficient method for evaluating the potential of investigational agents to induce CYP3A4.

Structural elucidation of a water-insoluble glucan produced by a cariogenic oral Streptococcus.

The structure of a water-insoluble polysaccharide produced by the D-glucosyl-transferase of Streptococcus mutans 6715 has been elucidated through periodate oxidation, Smith degradation, dextranase digestion, concanavalin A binding studies, and methylation combined with g.l.c.-m.s. analysis. These studies show that the D-glucan is comprised of 67% alpha-(1----3) linkages in a contiguous backbone with the remaining 33% as alpha-(1----6) linkages, possibly as linear residues extending from alpha-(1----6) branch points. Of the residues, 14% are branch points and the ratio of linear alpha-(1----3) residues in the backbone to alpha-(1----6) residues in the side chain was found to be 5:2. Dextranase digestion and Smith degradation both gave rise to a high-molecular-weight fraction that is only alpha-(1----3) linked.

The pneumatic tube system does not affect complete blood count results; a validation study at a tertiary care hospital.

INTRODUCTION: Effect of the pneumatic tube system (PTS) on sample quality is controversial. Herein we aim at evaluating the impact of sample transportation via the PTS on complete blood count (CBC) results. METHODS: Duplicate CBC samples from normal donors and anemic patients were sent in parallel to the laboratory for testing through the PTS and the courier (CO). We used scatter plots, Bland-Altman plots, correlation coefficient (r), and coefficient of determination for the validation. RESULTS: A total of 115 samples (donors: 59, patients: 56) were tested. There was excellent correlation between both methods for red blood cell parameters (r range = 0.9213-0.9958) and platelet count. White blood cell (WBC) count and differential count showed similar results (r range = 0.8605-0.9821) for all, with exception of basophils which showed modest correlation (r = 0.4827 for patients and 0.5758 for normal donors). Most of the differences in measurement of all CBC parameters were within the 95% confidence interval of the mean difference on Bland-Altman plots. CONCLUSION: Modern PTS can be safely used for transporting CBC samples.

Biomechanical strength of two laparoscopic herniorrhaphy techniques in a cadaveric diaphragm and in a neoprene model.

OBJECTIVES: Our objectives were to 1) Biomechanically compare two laparoscopic repair techniques; an automated suturing device and a stapling device to conventional open suturing, and 2) Evaluate a model for canine diaphragmatic tissue by comparisons to similar constructs in fresh diaphragms. We hypothesized that automated suturing is biomechanically superior to laparoscopic stapling in dogs, and that neoprene defect repair is an acceptable model for experimental cadaveric diaphragm herniorrhaphy. MATERIALS AND METHODS: Samples of diaphragm pars costalis were prepared with defects mimicking radial muscular tears. Defects were repaired using conventional open suturing, laparoscopic automated suturing, and laparoscopic stapling techniques. Similar defects were created in 6.35 mm thick single-sided neoprene. Samples were biomechanically tested across a biaxial loading machine. Site and mode of failure were noted for all samples. RESULTS: In both the diaphragm muscle and neoprene, the laparoscopic stapling technique was significantly weaker. The neoprene model showed a similar failure load as the diaphragm in both laparoscopic techniques, and a similar stiffness in an open-sutured and stapled diaphragm compared to the neoprene samples. Site and mode of failure in neoprene were similar to cadaveric diaphragmatic tissue, but the overall median load-to-failure was higher for the neoprene. CONCLUSION: The strength of laparoscopically repaired simulated diaphragmatic hernias was higher with an automated suture technique than with a stapling technique. Neoprene defect repair is an acceptable model of canine diaphragmatic herniorrhaphy for biomechanical testing.

Determination of cinnamyl anthranilate in perfume, cologne, and toilet water by liquid chromatography with fluorescence detection.

A liquid chromatographic method with fluorescence detection was developed for the determination of cinnamyl anthranilate in perfumes and other fragrance compositions. The method was evaluated by conducting recovery studies of 10 different commercial fragrance compositions to which cinnamyl anthranilate had been added at levels of 0.1, 0.5, and 1.0 mg/mL. Recoveries ranged from 91 to 103% with a mean of 97% and a standard deviation of +/- 3.3%.

A liquid chromatography-mass spectrometry method to measure stable isotopic tracer enrichments of glycerol and glucose in human serum.

Stable isotopes are commonly used as tracers for the measurement of glycerol and glucose kinetics in metabolic studies. Traditionally, the analysis of these isotopes has been performed using gas chromatography-mass spectrometry, which requires that the analytes first be derivatized. The derivatization process adds considerable complexity to the method. Liquid chromatography-mass spectrometry (LCMS) can measure many metabolites directly with limited sample preparation. We present a novel analytical method for the measurement of [1,1,2,3,3-(2)H(5)]glycerol (d(5)-glycerol) and [6,6-(2)H(2)]glucose (d(2)-glucose) isotopic tracer enrichments in human serum in a single run by LCMS. After a simple extraction step, the sample is separated isocratically by HPLC, and the isotopes are measured using positive electrospray ionization with selected ion monitoring of the sodium-adduct ions. The method is linear over a wide range of d(2)-glucose and d(5)-glycerol enrichments. The within-day standard deviation of measurement of serum samples was 0.05 mole% excess (MPE) for d(2)-glucose and 0.25 MPE for d(5)-glycerol. The variation of tracer enrichment among days was about double that measured within 1 day.

High-performance liquid chromatographic-fluorometric determination of cinnamaldehyde in perfume, cologne and toilet water.

A high-performance liquid chromatographic (HPLC)-fluorometric method is described for the determination of trans-cinnamaldehyde in fragrances. The fragrance is added to isooctane and extracted with an aqueous solution of the sodium salt of 6-aminocaproic acid to isolate the aldehyde fraction. After dilution with water, an aliquot of the extract is added to a solution of 1,2-diaminonaphthalene monosulfate in dilute formic acid. The fluorescent derivative of cinnamaldehyde, 2-styrylnaphth[1,2-d]imidazole, is prepared by incubating and then cooling the solution and adding pyridine. Aliquots of the fluorophore solution are analyzed on a reversed-phase C18 HPLC column by using a buffered tetrahydrofuran-water eluent. Cinnamaldehyde is quantitated by comparing fluorescence emission intensity with that of a standard. Recoveries from samples of various commercial fragrances, spiked with cinnamaldehyde at the 0.01, 0.05 and 0.1% levels, ranged from 94 to 112% with a mean of 103% and a standard deviation of 5.3. The limit of detection is approximately 1 ng.