Efficacy of galactose and adalimumab in patients with resistant focal segmental glomerulosclerosis: report of the font clinical trial group.

BACKGROUND: Patients with resistant focal segmental glomerulosclerosis (FSGS) who are unresponsive to corticosteroids and other immunosuppressive agents are at very high risk of progression to end stage kidney disease. In the absence of curative treatment, current therapy centers on renoprotective interventions that reduce proteinuria and fibrosis. The FONT (Novel Therapies for Resistant FSGS) Phase II clinical trial (NCT00814255, Registration date December 22, 2008) was designed to assess the efficacy of adalimumab and galactose compared to standard medical therapy which was comprised of lisinopril, losartan, and atorvastatin. METHODS: Key eligibility criteria were biopsy confirmed primary FSGS or documentation of a causative genetic mutation, urine protein:creatinine ratio >1.0 g/g, and estimated glomerular filtration rate (eGFR) >40 ml/min/1.73 m(2). The experimental treatments - adalimumab, galactose, standard medical therapy-- were administered for 26 weeks. The primary endpoint was a 50 % reduction in proteinuria with stable eGFR. RESULTS: Thirty-two subjects were screened and 21 were assigned to one of the three study arms. While none of the adalimumab-treated subjects achieved the primary outcome, 2 subjects in the galactose and 2 in the standard medical therapy arm had a 50 % reduction in proteinuria without a decline in eGFR. The proteinuria response did not correlate with serial changes in the serum glomerular permeability activity measured by the Palb assay or soluble urokinase plasminogen activator receptor (suPAR). There were no serious adverse effects related to treatments in the study. CONCLUSIONS: Recruitment into this trial that addressed patients with resistant FSGS fell short of the enrollment goal. Our findings suggest that future studies of novel therapies for rare glomerular diseases such as FSGS may benefit from enrollment of patients earlier in the course of their disease. In addition, better identification of patients who are likely to respond to a new treatment based on biomarkers suggesting involvement of the disease pathway targeted by the experimental agent may reduce the required sample size and increase the likelihood of a favorable outcome.

Insulin enhances glucose-stimulated insulin secretion in healthy humans.

Islet beta-cells express both insulin receptors and insulin-signaling proteins. Recent evidence from rodents in vivo and from islets isolated from rodents or humans suggests that the insulin signaling pathway is physiologically important for glucose sensing. We evaluated whether insulin regulates beta-cell function in healthy humans in vivo. Glucose-induced insulin secretion was assessed in healthy humans following 4-h saline (low insulin/sham clamp) or isoglycemic-hyperinsulinemic (high insulin) clamps using B28-Asp insulin that could be immunologically distinguished from endogenous insulin. Insulin and C-peptide clearance were evaluated to understand the impact of hyperinsulinemia on estimates of beta-cell function. Preexposure to exogenous insulin increased the endogenous insulin secretory response to glucose by approximately 40%. C-peptide response also increased, although not to the level predicted by insulin. Insulin clearance was not saturated at hyperinsulinemia, but metabolic clearance of C-peptide, assessed by infusion of stable isotope-labeled C-peptide, increased modestly during hyperinsulinemic clamp. These studies demonstrate that insulin potentiates glucose-stimulated insulin secretion in vivo in healthy humans. In addition, hyperinsulinemia increases C-peptide clearance, which may lead to modest underestimation of beta-cell secretory response when using these methods during prolonged dynamic testing.

Communicating With Diverse Patients About Participating in a Biobank: A Randomized Multisite Study Comparing Electronic and Face-to-Face Informed Consent Processes.

Some individuals' understanding of informed consent (IC) information may improve with electronic delivery, but others may benefit from face-to-face (F2F). This randomized, multisite study explores how individuals from diverse backgrounds understand electronic IC documents versus F2F, their confidence in understanding, and enrollment in research. A total of 501 patients at two U.S. biobanks with diverse populations participated. There were no overall differences between electronic and F2F understanding, but F2F predicted higher confidence in understanding and enrollment. Ethnicity and a higher educational level predicted higher understanding and confidence. Study findings suggest that electronic consent may lead to better understanding for non-Hispanic patients of higher socioeconomic status. F2F processes may lead to better understanding and higher enrollment of patients from Hispanic and lower socioeconomic levels. Researchers should carefully consider how they implement electronic IC processes and whether to maintain an F2F process to better address the needs and limitations of some populations.

Single-Dilution COVID-19 Antibody Test with Qualitative and Quantitative Readouts.

The coronavirus disease 2019 (COVID-19) global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to place an immense burden on societies and health care systems. A key component of COVID-19 control efforts is serological testing to determine the community prevalence of SARS-CoV-2 exposure and quantify individual immune responses to prior SARS-CoV-2 infection or vaccination. Here, we describe a laboratory-developed antibody test that uses readily available research-grade reagents to detect SARS-CoV-2 exposure in patient blood samples with high sensitivity and specificity. We further show that this sensitive test affords the estimation of viral spike-specific IgG titers from a single sample measurement, thereby providing a simple and scalable method to measure the strength of an individual's immune response. The accuracy, adaptability, and cost-effectiveness of this test make it an excellent option for clinical deployment in the ongoing COVID-19 pandemic.IMPORTANCE Serological surveillance has become an important public health tool during the COVID-19 pandemic. Detection of protective antibodies and seroconversion after SARS-CoV-2 infection or vaccination can help guide patient care plans and public health policies. Serology tests can detect antibodies against past infections; consequently, they can help overcome the shortcomings of molecular tests, which can detect only active infections. This is important, especially when considering that many COVID-19 patients are asymptomatic. In this study, we describe an enzyme-linked immunosorbent assay (ELISA)-based qualitative and quantitative serology test developed to measure IgG and IgA antibodies against the SARS-CoV-2 spike glycoprotein. The test can be deployed using commonly available laboratory reagents and equipment and displays high specificity and sensitivity. Furthermore, we demonstrate that IgG titers in patient samples can be estimated from a single measurement, enabling the assay's use in high-throughput clinical environments.

Development, clinical translation, and utility of a COVID-19 antibody test with qualitative and quantitative readouts.

The COVID-19 global pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) continues to place an immense burden on societies and healthcare systems. A key component of COVID-19 control efforts is serologic testing to determine the community prevalence of SARS-CoV-2 exposure and quantify individual immune responses to prior infection or vaccination. Here, we describe a laboratory-developed antibody test that uses readily available research-grade reagents to detect SARS-CoV-2 exposure in patient blood samples with high sensitivity and specificity. We further show that this test affords the estimation of viral spike-specific IgG titers from a single sample measurement, thereby providing a simple and scalable method to measure the strength of an individual's immune response. The accuracy, adaptability, and cost-effectiveness of this test makes it an excellent option for clinical deployment in the ongoing COVID-19 pandemic.

Reduction in delay time of high-dwell volume pumps in LC-MS applications using short-term low-ratio split flow.

We present a simple hardware design which reduces run time of gradient-based LC/MS applications and improves system equilibration. Our approach does not sacrifice efficiency of chromatographic separation, and does not affect analyte retention time and therefore does not require revalidation. Our technical design is based on a six-port/two-position switching valve and flow splitter installed prior to the LC column. This design minimizes time delays caused by the high-dwell volume of some LC pumps. Implementation of short-term (40-55 s) low-ratio (1:10) flow splitting reduced delay times by over four-fold in our application. This approach allowed hardware-associated time delays to be minimized. Alternative plumbing suggestions are also discussed.

High dead volume pumps: delay time reduction by short-term low-ratio split flow in LC/MS applications.

The aim of our work was to develop a low-cost, simple and reliable solution to reduce LC/MS analysis time by compensating for limitations inherent to high dead volume standard HPLC pumps. In our approach, we utilized a temporary (sub-1 min) low ratio flow split (approximately 1:10) at 5 mL/min pump flow before the column. During this short period, 90% of the entire pump flow is delivered to waste and used for fast pump/system equilibration. Although full-time flow splitting is widely used in capillary/nano applications (usually with high split ratios in the hundreds or thousands), to our knowledge, this is the first time that short-term low-ratio flow splitting has been used in conventional LC/MS applications.

Cross contamination of intramyocellular lipid signals through loss of bulk magnetic susceptibility effect differences in human muscle using (1)H-MRSI at 4 T.

Cross contamination of intramyocellular lipid (IMCL) signals through loss of bulk magnetic susceptibility (BMS) differences was detected in human muscles using proton magnetic resonance spectroscopic imaging ((1)H-MRSI) at 4 T by varying nominal voxel sizes on healthy subjects. In soleus muscle the IMCL content estimated in 1.00-ml-sized voxels was 15% and 30% higher than that in 0.25-ml voxels for nonobese (P < 0.05) and obese (P < 0.01) subjects, respectively, whereas no effect was observed on IMCL estimation in tibialis posterior (TP) and tibialis anterior (TA) regions for different voxel sizes. The unbiased 0.25-ml voxel size (1)H-MRSI method was applied to measure IMCL content in nonobese sedentary (NOB-Sed), moderately trained (Ath), sedentary obese (OB), and Type 2 diabetic mellitus (DM) subjects. IMCL content in soleus was greatest in OB, with decreasing content in DM, Ath, and NOB-Sed, respectively (12.6 +/- 1.6, 9.7 +/- 1.8, 7.4 +/- 1.0, 4.9 +/- 0.5 mmol/kg wet wt; P < 0.05 by ANOVA; P < 0.05 OB vs. NOB-Sed or Ath). In TA, IMCL was equivalently elevated in DM and OB, which was higher than in Ath or NOB-Sed, respectively (4.2 +/- 0.4 and 4.2 +/- 0.7 vs. 2.7 +/- 0.5 and 1.5 +/- 0.3 mmol/kg wet wt; ANOVA, P < 0.05; P < 0.05 DM or OB vs. NOB-Sed). We conclude that IMCL content is overestimated when voxel size exceeds 0.25 ml despite measurement by optimized high-resolution (1)H-MRSI at high field. When IMCL is measured unbiased by concomitant obesity, we find that it is strongly influenced by muscle type, training status, and the presence of obesity and Type 2 diabetes.

Acute elevation of NEFA causes hyperinsulinemia without effect on insulin secretion rate in healthy human subjects.

Increased circulating levels of nonesterified free fatty acids (NEFA) have been observed in such hyperinsulinemic states as obesity, impaired glucose tolerance, diabetes, and dyslipidemia where they have been causally linked to the development of insulin resistance and hyperinsulinemia. The concentration of NEFA in plasma is believed to have direct modifying effects on insulin secretion and clearance. It remains controversial whether acute increases in NEFA potentiate insulin secretion in human subjects. We studied the effect of an acute elevation of NEFA during lipid-heparin infusion compared to a glycerol-only control on glucose-stimulated insulin secretion and clearance during a 120-min hyperglycemic (10 mM) clamp in 7 healthy normoglucose-tolerant volunteers. The metabolic clearance rate of C-peptide (MCR(CP)) was measured in each subject during the study by simultaneous infusion of C-peptide. Insulin secretion rate (ISR) was calculated from deconvolution of C-peptide data after correction for the rate of C-peptide infusion. Clearance rate of insulin (MCR(INS)) was calculated based upon endogenous ISR. Plasma glucose (mg/dL): basal (90-115 min) 90.2 +/- 2.8 vs. 90.2 +/- 2.3; clamp (150-240 min) 180.5 +/- 2.8 vs. 180.9 +/- 1.3. Plasma insulin (pmol/L): prebasal (fasting) 29.6 +/- 10.0 vs. 29.8 +/- 10.6; basal (90-115 min) 30.1 +/- 9.2 vs. 34.5 +/- 12.1; second phase clamp (210-240 min) 127.6 +/- 18.2 vs. 182.5 +/- 17.3*. Plasma NEFA (mM): prebasal 0.47 +/- 0.08 vs. 0.52 +/- 0.09; basal 0.35 +/- 0.05 vs. 0.98 +/- 0.02*; clamp (122-240 min) 0.06 +/- 0.02 vs. 0.77 +/- 0.06*. ISR (pmol/min): prebasal 72.7 +/- 7.5 vs. 72.0 +/- 7.9; second phase clamp (210-240 min) 268.5 +/- 27.2 vs. 200.2 +/- 23.7. MCR(INS) (mL/min): prebasal 3393 +/- 488 vs. 3370 +/- 511; clamp 2284 +/- 505 vs. 1214 +/- 153* (*p < 0.05 glycerol vs. intralipid/heparin). This study demonstrates that acute NEFA elevation causes hyperinsulinemia due to a significant decrease in systemic insulin clearance without increasing rates of insulin secretion.

The effectiveness of the use of electrocautery with chondroplasty in treating chondromalacic lesions: A randomized prospective study.

PURPOSE: To determine the clinical effect of electrocautery with arthroscopic chondroplasty on chondromalacic tissue. TYPE OF STUDY: A randomized, prospective study. METHODS: In a prospective study, 146 patients were randomly placed in either a control group (chondroplasty alone) or a treatment group (chondroplasty and electrocautery). Intraoperative findings in both treatment and control groups were classified by both the extent of chondromalacia and the number of compartments in which chondromalacia was diagnosed. In our study, we used 6 defined compartments: medial and lateral tibial plateau, medial and lateral femoral condyles, patella, and femoral trochlea. Patients were followed up at 1 year and evaluated using the Lysholm scale. Postoperative Lysholm scores were matched against compartment involvement and compared between groups. RESULTS: There was no significant difference in the patients with grade 2 chondromalacia in either control or cautery group (P >.5). Groups with grade 3 chondromalacia showed a significant difference favoring the control group (P <.05). A significant difference was found in comparing 2-compartment chondromalacia between the 2 treatment cohorts, again, favoring the control group (P =.01). The remaining groups of multiple compartment chondromalacia showed no significant difference, indicating that the postoperative result was independent of the use of electrocautery. CONCLUSIONS: This study shows that electrocautery as an adjunct to chondroplasty offers little benefit in the treatment of chondromalacic lesions and may, in fact, limit successful outcome.

The "muffin test"--an alternative to the oral glucose tolerance test for detecting impaired glucose tolerance.

OBJECTIVE: The aim of this study was to compare the effectiveness of the "muffin test" (MT) with that of the oral glucose tolerance test (OGTT) in diagnosing impaired glucose tolerance (IGT). METHODS: This is a cross-sectional study in a single academic institution. The participants were 73 women aged 42 to 58 years, less than 36 months after menopause, recruited for the Kronos Early Estrogen Prevention Study Trial. After a 10-hour fasting blood draw, the participants were provided a muffin and a beverage. Two-hour glucose levels were assessed. A subset underwent metabolic testing consisting of an OGTT (n = 12) and a mixed-meal tolerance test (n = 10). The main outcome measures were the prevalence of IGT and 2-hour glucose measurements after each testing method. RESULTS: Two-hour glucose levels were linearly related to fasting values by multivariable linear regression. This association was exaggerated in overweight (body mass index, 25 kg/m2) women (coefficient, 1.43; P < 0.001). Two-hour OGTT and MT glucose levels were comparable (P > 0.05); 2-hour glucose levels after OGTT were slightly lower than after the mixed-meal tolerance test (P < 0.05). CONCLUSIONS: The prevalence of IGT was 11% (8 of 73). Fasting plasma glucose alone would have missed 63% of cases (five of eight cases). The MT demonstrated 100% sensitivity and specificity for diagnosing IGT compared with the gold standard OGTT. This small pilot study should be confirmed in a larger prospective group of participants.

The dilemma of the wedding band.

The postoperative infection rate in procedures where no ring is worn, and those where a plain metal wedding band is worn under the glove was studied retrospectively. From January 1998 through June 2002, 2127 surgeries were performed by the lead author (D.T.S.), the first 2 years without a wedding band and the next 2 years with a simple platinum wedding band worn under the glove. Attention was paid to sliding the ring proximal and distal on the finger, ensuring scrub solution was under the ring and that the area of skin below the ring was cleansed. Twenty-two postoperative infections were recorded in 2127 surgeries. This is a postoperative infection rate of 1.0%, and <1 (0.449) postoperative infection per month. The "no ring" group totaled 987 cases with an infection rate 1.6%; the "ring" group revealed an infection rate of 0.53% in 1140 cases. Previous studies of jewelry in the operating room do not discuss the type of wedding ring worn, nor do they demonstrate an increased infection rate with wearing jewelry. This study suggests that there is no correlation between wearing a plain wedding band under the surgical glove and an increase in postoperative infections. The crevices and cuticle of the fingers and nails may provide more significant infection risk than a plain metal wedding band. This is a level III retrospective cohort study.

Flow inconsistency: the evil twin of column switching--hardware aspects.

Solvent flow, generated by HPLC pumps is consistent and accurate. This statement, while true for single column (one dimensional) liquid chromatography applications, may not apply to column switching applications. Connection of pumps and/or columns to one flow path may cause substantial pressure changes. Immediate post valve switch pressure differences between pumps can cause backflow where the mobile phase stored at higher pressure will temporary flow into the lower pressure area. A more common side effect of column switching is flow inconsistency during pump pressurization. For the duration of pump pressurization, liquid flow through the column will be smaller than expected since the HPLC column acts like a flow restrictor.

Standardization of C-peptide measurements.

BACKGROUND: C-peptide is a marker of insulin secretion in diabetic patients. We assessed within- and between-laboratory imprecision of C-peptide assays and determined whether serum calibrators with values assigned by mass spectrometry could be used to harmonize C-peptide results. METHODS: We sent 40 different serum samples to 15 laboratories, which used 9 different routine C-peptide assay methods. We also sent matched plasma samples to another laboratory for C-peptide analysis with a reference mass spectrometry method. Each laboratory analyzed 8 of these samples in duplicate on each of 4 days to evaluate within- and between-day imprecision. The same 8 samples were also used to normalize the results for the remaining samples to the mass spectrometry reference method. RESULTS: Within- and between-run CVs ranged from <2% to >10% and from <2% to >18%, respectively. Normalizing the results with serum samples significantly improved the comparability among laboratories and methods. After normalization, the differences among laboratories in mean response were no longer statistically significant (P = 0.24), with least-squares means of 0.93-1.02. CONCLUSIONS: C-peptide results generated by different methods and laboratories do not always agree, especially at higher C-peptide concentrations. Within-laboratory imprecision also varied, with some methods giving much more consistent results than others. These data show that calibrating C-peptide measurement to a reference method can increase comparability between laboratories.

LC/MS quantitative study of glucose by iodine attachment.

We explored the potential of iodine attachment to improve the sensitivity of glucose measurement by LC/MS. After sample preparation, glucose was separated by normal phase chromatography, followed by anionization by I(-)-attachment prior to MS by post-column addition of a methanolic solution of iodoform. Iodine is capable of forming an anionic adduct with neutral monosaccharides in negative ion mode electrospray mass spectrometry. Quasi-molecular ions [M+I]- of glucose, and [6,6-(2)H2]glucose (abbreviated d2-glucose) internal standard were quantitated in selected ion monitoring (SIM) mode. Iodine attachment LC/MS analysis provided high sensitivity, superior to GC/MS. It greatly simplified sample preparation and increased throughput. The advantages of iodine attachment can be realized even on old mass spectrometers. A LOD of 50 pg glucose on column was achieved. Due to iodine's predisposition to sublimate, the iodoform concentration must be minimized, which adds complexity to method development. To optimize reagent concentration we developed an efficient and flexible gradient-based delivery platform. Strategy for method development with iodoform is given.

Nondigest liberation of biomarkers from plasma: a novel two-stage ultrafiltration approach.

A simple procedure for sample preparation of human plasma by two stages of ultrafiltration using one device is described. Our approach is useful for nondigest liberation of biomarkers bound to albumin and other plasma proteins. The analyte contained in the ultrafiltrate can be directly analyzed without additional sample preparation, and quantified by 2-D RP-RP LC/MS.

Calculating glucose fluxes during meal tolerance test: a new computational approach.

A new calculation method is proposed to quantify the endogenous glucose production (EGP), the glucose appearance rate due to meal ingestion (R(a meal)), and the glucose disposal (R(d)) during a three-tracer study design. The method utilizes the maximum likelihood theory combined with a regularization method to achieve a theoretically coherent computational framework. The method uses the two-compartment formulation of the glucose kinetics. Instead of assuming smoothness of unlabeled and labeled glucose concentrations, the method assumes that the EGP, the R(a meal), and the fractional glucose clearance are smooth, increasing plausibility of their individual estimates. The method avoids transformation of the measurement errors, which may skew the estimates of the EGP, R(a meal), and R(d) with the traditional approach. Finally, the sequential nature of the calculations is replaced by calculating the EGP, R(a meal), and R(d) in "one go" to avoid the propagation of the errors from the EGP and R(a meal) into R(d). An example study is shown demonstrating the utility of the approach. A better performance of the new method is demonstrated in a simulation study.

Trace LC/MS quantitative analysis of polypeptide biomarkers: impact of 1-D and 2-D chromatography on matrix effects and sensitivity.

We investigated the impact of one dimension (single reverse phase (RP) column) and two dimension (two different RP columns) chromatographic methods on SIM (MS) and multiple reaction monitoring (MRM; MS/MS) performance from human plasma. We find that MRM analysis is clearly preferable for 1-D applications; however, implementation of SIM detection in conjunction with 2-D separation technique resulted in an over 60-fold increase in analyte peak area and improved S/N compared to MRM for our analyte, human C-peptide. Implementation of a 2-D RP-RP technique with SIM detection is capable of eliminating matrix effects and greatly increases signal response and data quality. For two large peptides in complex biological samples, we found that a 2-D approach performed better than high quality sample preparation together with 1-D chromatography and MRM, even on a high-end mass spectrometer.

Increased intrahepatic triglyceride is associated with peripheral insulin resistance: in vivo MR imaging and spectroscopy studies.

Recent studies have indicated that the mass/content of intramyocellular lipid (IMCL), intrahepatic triglyceride (IHTG), visceral fat (VF), and even deep abdominal subcutaneous fat (SF) may all be correlated with insulin resistance. Since simultaneous measurements of these parameters have not been reported, the relative strength of their associations with insulin action is not known. Therefore, the goals of this study were 1) to simultaneously measure IMCL, IHTG, VF, and abdominal SF in the same nondiabetic individuals using noninvasive (1)H-magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) and 2) to examine how these fat stores are correlated with systemic insulin sensitivity as measured by whole body glucose disposal (R(d)) during euglycemic-hyperinsulinemic clamp studies. Positive correlations were observed among IMCL, IHTG, and VF. There were significant inverse correlations between whole body R(d) and both IMCL and VF. Notably, there was a particularly tight inverse correlation between IHTG and whole body R(d) (r = -0.86, P < 0.001), consistent with an association between liver fat and peripheral insulin sensitivity. This novel finding suggests that hepatic triglyceride accumulation has important systemic consequences that may adversely affect insulin sensitivity in other tissues.

Two-dimensional reverse phase-reverse phase chromatography: A simple and robust platform for sensitive quantitative analysis of peptides by LC/MS. Hardware design.

We have revised current two-dimensional RP-RP approaches and developed a new robust 2-D RP-RP platform. This platform was implemented on an Agilent 1100 2-D liquid chromatography system and is based on high pressure switching between two high-resolution RP columns. An independent binary gradient was implemented for each dimension. The powerful combination of dual analytical columns with independent gradient elution achieves high analyte purity, effectively eliminates matrix effects, and maximizes MS sensitivity in Q1 SIM comparable to the sensitivity enhancements of MS/MS-based methods. Implementation of dual simultaneous gradient profiles (overlapped gradients) reduces 2-D method run-time to the scale of 1-D method run-times. This robust and sensitive approach is particularly suitable for hydrophobic peptides and small proteins and can be used as a routine standard technique for enhanced on-line peptide purification coupled with mass spectrometric detection.