Development of a broad-spectrum one-step immunoassay for detection of glucocorticoids in milk using magnetosome-based immunomagnetic beads

Development of a sensitive and rapid fluorescence polarization immunoassay for high throughput screening eight glucocorticoids in beef

A multiresidue method for the determination of 12 glucocorticoids (clobetasol propionate, budesonide, triamcinolone, triamcinolone acetonide, fludrocortisone acetate, flumethasone, beclomethasone, prednisone acetate, 6-α-methylprednisolone, hydrocortisone, cortisone, and prednisone) in bovine milk was developed using liquid chromatography with tandem mass spectrometry. Isoflupredone was used as an internal standard. Milk samples were treated with ethyl acetate to extract glucocorticoids and were frozen at -20°C for 6h to precipitate fat. The extract was dried under nitrogen, and residues were dissolved in an acetonitrile/water solution. A further clean-up step was used by dispersive solid-phase extraction, with octadecyl silica and primary secondary amine as the absorbents. The recoveries of glucocorticoids spiked at 0.5, 1.0, 10.0 μg/kg ranged from 75.7 to 117.3%, except for clobetasol propionate and budesonide (16.1-49.5%). The limits of quantification were 0.01-0.5μg/kg in milk. This method has been successfully applied in real samples. The results demonstrated that this method is simple, robust, and suitable for identification of glucocorticoid residues in milk.

Thin-layer chromatographic detection of glucocorticoids.

A broad-spectrum monoclonal antibody (C4 MAb) against the capsid proteins (CPs) of plant potyviruses has been generated in previous studies. To clarify which epitope is recognized by this MAb, epitope mapping was performed via phage display library screening and amino acid substitution analysis. Subsequently, a 12-residue epitope in the core region of potyvirus CPs was identified and termed the C4 epitope (WxMMDGxxQxxY/F). This epitope contains tryptophan and tyrosine residues that are crucial for reacting with C4 MAb. The CP of Odontoglossum ringspot tobamovirus (ORSV) separately fused with the C4 epitope of Konjak mosaic potyvirus (KoMV), Zantedeschia mild mosaic potyvirus (ZaMMV), or Dasheen mosaic potyvirus (DsMV) was expressed in a bacterial system and purified. The results of indirect ELISA and Western blotting demonstrated that the C4 epitope of KoMV (Ko) fused to ORSV CP showed the strongest binding affinity to C4 MAb among the three viral epitope tags examined. The binding affinity between Ko tag (WTMMDGEEQIEY) and C4 MAb was determined. To examine the applicability of the Ko tag in planta, GFP and ORSV CP were transiently expressed in Nicotiana benthamiana, and both Ko-tagged proteins were specifically detected using C4 MAb. The Ko tag did not affect the silencing suppressor function of Tomato bushy stunt tombusvirus P19 in N. benthamiana. Furthermore, Ko-tagged EGFP could be successfully expressed, specifically detected and subsequently immunoprecipitated using C4 MAb in a mammalian cell system. Thus, the present study identified a common C4 epitope of potyviruses recognized by the broad-spectrum C4 and PTY 1 MAbs, and the results indicated that the newly designed Ko tag is suitable for application in bacterial, plant, and mammalian cell systems.

It has been shown previously that topical corticosteroid treatment decreases collagen synthesis in human skin in vivo and that the adverse effects are due to reduced collagen synthesis. The aim of the present study was to evaluate the effect of hydrocortisone, hydrocortisone-17-butyrate and betamethasone on collagen synthesis in human skin in vivo. Fourteen healthy male volunteers applied hydrocortisone, hydrocortisone-17-butyrate, betamethasone and vehicle twice a day for one week to four separate areas marked on their abdominal skin. The collagen synthesis rate in the skin was measured by assaying collagen propeptides from the suction blisters induced on the treated areas. Aminoterminal propeptide of type I procollagen (PINP) and aminoterminal propeptide of type III procollagen (PIIINP) were measured from skin blister fluid using radioimmunoassays. Skin thickness was measured with ultrasound. Hydrocortisone decreased the two propeptides studied in the suction blister fluids less than did hydrocortisone-17-butyrate and betamethasone, but the interindividual variation was great. Hydrocortisone-17-butyrate and betamethasone had almost similar decreasing effects on the propeptides in the suction blister fluid. Hydrocortisone decreased the concentrations of PINP and PIIINP by about 35%. In some subjects (4/14) the decline of the collagen propeptide levels was over 50%. The decline in the concentration of PINP was 63% by hydrocortisone-17-butyrate and 69% by betamethasone, while the decrease in PIIINP was 55% by hydrocortisone-17-butyrate and 62% by betamethasone. None of the treatments had any effect on skin thickness within one week. In conclusion, it seems that hydrocortisone is less atrophogenic than hydrocortisone-17-butyrate and betamethasone, as shown by radioimmunoassays for collagen propeptides. The order of inhibitory potency of the three glucocorticoids on collagen synthesis was hydrocortisone < hydrocortisone-17-butyrate < betamethasone. Thus, assay of collagen propeptides from suction blisters can be used to screen various steroids with respect to their action on collagen synthesis.

Rapid determination of 2,4-diaminopyrimidine residues through sample pretreatment using immunomagnetic bead purification along with HPLC–UV

Objective To screen and prepare a broad-spectrum monoclonal antibody against Streptococcus pneumoniae (S.pneumoniae) surface protein A (PspA) and to evaluate its potential in clinical practice. Methods Hybridoma cells were screened and inoculated into the abdominal cavities of BALB/c mice to prepare antibodies in ascites. Monoclonal antibodies were obtained by ammonium sulfate precipitation and protein A affinity chromatography and then identified by SDS-PAGE and Western blot. Their specificity, isoforms and killing activities in vitro were analyzed. Results A broad-spectrum monoclonal antibody that recognized PspA subclasses 2, 3 and 4 was obtained. Its in vitro killing rate against S. pneumoniae reached 40.3%. Conclusions A broad-spectrum monoclonal antibody that could specifically bind to PspA was successfully prepared with a strong in vitro killing activity. This study provided reference for clinical diagnosis of S. pneumoniae-related diseases, quality assessment of S. pneumoniae vaccines and further research on monoclonal antibody therapeutics. Key words: Streptococcus pneumoniae; Streptococcus pneumoniae surface protein A (PspA); Monoclonal antibody

An in vitro comparison of commonly used topical glucocorticoid preparations

Adult studies evaluating corticosteroids have found varied efficacy. One study showing mortality benefit utilized fludrocortisone (FLU) and hydrocortisone (HC) (Effect of treatment with low doses of hydrocortisone and fludrocortisone on mortality in patients with septic shock. JAMA 288:862-871, 2002). Use of FLU in children has not been described. We developed a protocol using HC for systemic inflammatory response syndrome (SIRS) and shock with optional addition of FLU. Addition of FLU to a HC-based steroid protocol is associated with decreased vasopressor duration without adverse effects in hypotensive children with SIRS. Retrospective review of low-dose HC and FLU supplementation in children with SIRS and fluid refractory shock. Patients receiving FLU in addition to HC were compared with patients receiving HC alone. Ninety-seven children with SIRS and shock received steroids. Sixty of 97 (62%) received FLU in addition to HC. Seventy-three children required dopamine (DA) infusion, and 56 received norepinephrine (NE). Overall mortality was 7/97 (7%), with 5/7 (71%) nonsurvivors receiving HC + FLU. Fifty of 97 (52%) children with SIRS met definition for sepsis. Septic children who received HC + FLU required NE for significantly shorter duration than those receiving HC alone (p = 0.011). Nineteen of 60 HC + FLU patients (32%) developed nonsymptomatic hypokalemia. Hypokalemia was significantly more common in HC + FLU patients compared with those receiving HC alone (p = 0.05). Overall, addition of FLU in children with SIRS was not associated with decreased vasopressor duration or vasopressor score. However, HC + FLU was associated with shorter duration of NE support in the septic subgroup. Hypokalemia was a frequent adverse finding with HC + FLU (p = 0.05). Use of FLU should be considered in further studies evaluating the role of steroids in refractory pediatric septic shock.

PurposeThe impact of patient’s characteristics on glucocorticoid (GC) replacement therapy in adrenal insufficiency (AI) is poorly evaluated. Aims of this study were to assess the influence of sex and body weight on GC dosing and to describe the choice of GC in AI of different etiologies.MethodsWe retrospectively evaluated hydrocortisone (HC) equivalent total daily dose (HC-TDD) and per-kg-daily dose (HC-KDD) in 203 patients (104 primary AI [pAI], 99 secondary AI [sAI]) followed up for ≥ 12 months. They were treated with HC, modified-release HC (MRHC) or cortisone acetate (CA) and fludrocortisone acetate (FCA) in pAI.ResultsAt baseline, CA was preferred both in pAI and sAI; at last visit, MRHC was most used in pAI (49%) and CA in sAI (73.7%). Comparing the last visit with baseline, in pAI, HC-TDD and HC-KDD were significantly lower (p = 0.04 and p = 0.006, respectively), while FCA doses increased during follow-up (p = 0.02). The reduction of HC-TDD and HC-KDD was particularly relevant for pAI women (p = 0.04 and p = 0.002, respectively). In sAI patients, no change of HC-KDD and HC-TDD was observed, and we found a correlation between weight and HC-TDD in males (r 0.35, p = 0.02).ConclusionsOur real-life study demonstrated the influence of etiology of AI on the type of GC used, a weight-based tailoring in sAI, a likely overdosage of GC treatment in pAI women at the start of treatment and the possibility to successfully increase FCA avoiding GC over-treatment. These observations could inform the usual clinical practice.

Relative immunosuppressive potency of therapeutic corticosteroids measured by whole blood lymphocyte proliferation

The photodegradation process of seven glucocorticoids (GCs), cortisone (CORT), hydrocortisone (HCORT), betamethasone (BETA), dexamethasone (DEXA), prednisone (PRED), prednisolone (PREDLO) and triamcinolone (TRIAM) was studied in tap and river water at a concentration close to the environmental ones. All drugs underwent sunlight degradation according to a pseudo-first-order decay. The kinetic constants ranged from 0.00082 min−1 for CORT to 0.024 min−1 for PRED and PREDLO. The photo-generated products were identified by high-pressure liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The main steps of the degradation pathways were the oxidative cleavage of the chain 17 for CORT, HCORT and the rearrangement of the cyclohexadiene moiety for the other GCs. The acute and chronic toxicity of GCs and of their photoproducts was assessed by the V. fischeri and P. subcapitata inhibition assays. The bioassays revealed no significant differences in toxicity between the parent compounds and their photoproducts, but the two organisms showed different responses. All samples produced a moderate acute toxic effect on V. fisheri and no one in the chronic tests. On the contrary, evident hormesis or eutrophic effect was produced on the algae, especially for long-term contact.

Trials evaluating hydrocortisone (HC) for septic shock are conflicting with all finding decreased time to shock reversal but few with mortality difference. Those with improved mortality included fludrocortisone (FC), but it is unknown if FC affected the outcome or is coincidental as there are no comparative data. The objective of this study was to determine the effectiveness and safety of FC + HC versus HC alone as adjunctive therapy in septic shock. A single-center, retrospective cohort study was conducted of medical intensive care unit (ICU) patients with septic shock refractory to fluids and vasopressors. Patients receiving FC + HC were compared with those receiving HC. Primary outcome was time to shock reversal. Secondary outcomes included in-hospital, 28-, and 90-day mortality; ICU and hospital length of stay (LOS); and safety. There were 251 patients included (FC + HC, n = 114 vs HC, n = 137). There was no difference in time to shock reversal (65.2 vs 71 hours; P = 0.24). Cox proportional hazards model showed time to first corticosteroid dose, full-dose HC duration, and use of FC + HC were associated with shorter shock duration, while time to vasopressor therapy was not. However, in 2 multivariable models controlling for covariates, use of FC + HC was not an independent predictor of shock reversal at greater than 72 hours and in-hospital mortality. No differences were seen in hospital LOS or mortality. Hyperglycemia occurred more frequently with FC + HC (62.3% vs 45.6%; P = 0.01). FC + HC was not associated with shock reversal at greater than 72 hours or decreased in-hospital mortality. These data may be useful for determining corticosteroid regimen in patients with septic shock refractory to fluids and vasopressors. Future prospective, randomized studies are needed to further evaluate the role of FC in this patient population.

An ultrasensitive and rapid fluorescent immunoassay based on a broad-spectrum monoclonal antibody (mAb) was developed to detect pyrrolizidine alkaloids (PAs) in honey samples. First, Discovery Studio software was used to analyze and predict the target hapten, and retrorsine (RTS) was selected to react with succinic anhydride (HS) for hapten synthesization. A sensitive and broad-spectrum monoclonal antibody (mAb 13E1) was obtained for nine PAs. Then, fluorescent gold nanoclusters (AuNCs) were conjugated with mAb as a label probe and used in establishing a qualitative and quantitative lateral flow immunoassay (AuNCs-LFIA) for the determination of four PAs (retrorsine, platyphylline, senecionine, integerrimine) in honey within 14min. The limits of detection (LOD) were 0.083μg/kg. The recovery in spiked honey samples were 87.98-119.57%, with coefficients of variation of ≤ 11.5%. A total of 45 commercial import honey samples from nine different countries were tested through AuNCs-LFIA and UPLC-MS/MS method, and satisfactory consistency (R2 = 0.995) was obtained. The rates of positive samples were 55.56% (25/45), and the average concentrations of four PAs were 3.24-46.47μg/kg. This ultrasensitive multi-PA method provides an alternative analytical tool for evaluating the human risk posed by the consumption of PA-contaminated honey.

Broad-spectrum monoclonal antibody and a sensitive multi-residue indirect competitive enzyme-linked immunosorbent assay for the antibacterial synergists in samples of animal origin