Basic evaluation of highly sensitive thyroid stimulating hormone immunoradiometric assay kits

Usefulness of three kinds of TSH kits by immunoradiometric assay (IRMA) was evaluated. They were able to measure low levels (less than 0.1 microIU/ml) in serum thyroid stimulating hormone (TSH) with incubation of short time (4 hours). In particular, RIABEAD II kit had a highly specific affinity for TSH and the normal range (+/- 2 S.D.) using it showed from 0.20 to 3.50 microIU/ml in 150 normal subjects. In patients with hyperthyroidism and in patients with hypothyroidism, the values of TSH were lower and higher than those of normal subjects, respectively. Another kits showed similar results. These results indicate that these TSH-IRMA kits are useful to evaluate serum TSH levels exactly.     

Evaluation and comparison of high-sensitivity immunoradiometric assay kits for thyroid stimulating hormone

Fundamental and clinical characteristics of 3 kinds of high-sensitivity immunoradiometric assay (IRMA) kits for thyroid stimulating hormone (TSH). i.e., RIA BEADS II (kit A), TSH kit Daiichi II (kit B) and Ab tube TSH 'Eiken' (kit C) and one conventional radioimmunoassay (RIA) kit, i.e., TSH kit Daiichi (kit D), were studied. In the recovery test and the reproducibility test, there was no significant difference between the 4 kits. The sensitivities of kits A, B and C were much higher than that of kit D, and those IRMA kits were sensitive enough to distinguish hyperthyroidism from normal samples. For low concentrations of TSH (less than 5 microU/ml), the data from kits D, B, C and A tended to show higher values in that order. The correlation between the data measured by kits B and D, and the tendency of kit A toward lower values agreed well with other reports.     

Fundamental and clinical evaluation of an immunoradiometric assay procedure "Amerwell AFP" for estimation of serum alpha-fetoprotein

The efficacy of assay procedure for estimation of serum alpha-fetoprotein (AFP) was examined on "Amerwell AFP" immunoradiometric assay (IRMA) using monoclonal AFP antibody. The condition of incubation was most satisfactory for 2 hours at 37 degrees C. Coefficients of variance for intraassay and interassay were 5.1-10.0% and 8.4-9.9% respectively. Dilution test gave satisfactory results. The binding capacity of microplate-well tagged monoclonal AFP antibody with AFP antigen was satisfactory for assay reactions. This method showed a good correlation to the AFP RIA bead (Dinabot Co.) method. The normal range (reference value) was within the level of 5.0 IU/ml due to Hoffmann's method in the examination of 860 subjects. Estimation of AFP with "Amerwell AFP" IRMA kit was a feasible routine method of clinical application for tumor marker.     

Clinical evaluation of immunoglobulin-E radioimmunoassay kit

An IgE RIA kit (Sandwich method; Dainabott), is used to obtain the following results. (1) Standard curve: Since the range of reproduction rate show 3.16-7.07% (C.V.), the curve become steep. (2) Incubations under controlled situation: Both of the incubations are controlled at 15-30 degrees C for 2 h. (3) Reproducibility test: Coefficients of variation (C.V.) of intra-assay and inter-assay variation are 2.32-3.94% and 2.92-3.92% respectively. (4) Recovery test: A result of the recovery test range between 100.1-101.7%. (5) Dilution test: Multiple dilution effects are observed. (6) Average counts of the serum IgE for the controlled and diseased groups: The average counts of the serum IgE for the controlled group, atopic diseased group, allergic rhinitis group and allergic bronchial asthma are 144.9 +/- 183.2 IU/ml, 1,099.0 +/- 2,782.4 IU/ml, 1,150.9 +/- 2,063.3 IU/ml and 600.7 +/- 686.4 IU/ml respectively. The value of the diseased groups have tendency to show higher averages than the controlled group. Since the controlled and diseased groups show wide distributions of the serum IgE level, there is no significant difference of two variations. However the diseased groups have tendency to show higher ratio of the serum IgE level in blood than the controlled groups. These basic researches are quite meaningful, because they are able to apply for a supplemental diagnosis of the atopic and parasitic disease.     

A fundamental and clinical study of ferritin 'Eiken' radioimmunoassay kit

We have measured serum ferritin level using double antibody radioimmunoassay kit (Eiken ICL) and evaluated the characteristics of the kit and clinical usefulness. Satisfactory results were observed in standard curve, reproducibility, dilution and recovery test. In clinical evaluation, we have measured in normal subjects and patients with various diseases. The range in normal males and females were 13.0-158.7 ng/ml and 7.3-73.0 ng/ml, respectively. Serum ferritin level was elevated in patients with hepatoma, biliary cancer, lung cancer and other malignant diseases. Measurement of serum ferritin value would be useful in the monitoring of cancer patients.     

Immunoradiometric assay for the in-vitro determination of thyroid stimulating hormone in human serum and plasma using solid phase anti-TSH cellulose particles

Summary Development, optimization and validation of immunoradiometric assay (IRMA) using solid phase-cellulose particles for the measurement of TSH in human serum or plasma are described. The preparation of ¹²⁵I anti-TSH monoclonal antibody (MoAb) was carried out by two different methods (Chloramine-T and Iodogen). It was found that Ch-T method gave approximately the same results as the iodogen method. The activation of cellulose particles using 1,1-carbonyl diimidazole (CDI) and coupling of these solid phase particles with sheep anti-TSH were carried out. Optimization and validation of the assay were undertaken. The reproducibility as measured by the intra- and inter-assay variations is acceptable. The recovery and dilution tests indicated accurate calibration and appropriate matrix. No significant position effect was recognized. The different modes of sampling tested did not affect significantly the results of the present study. The present technique agreed well with the currently used commercial kit (DPC, IRMA). The cellulose particles of the present system for estimation of TSH retain their characteristics during storage for 6 months at 4 °C. In conclusion, this technique proved to be sensitive, specific, precise and accurate for routine laboratory use.     

Purification and determination of human prostate specific antigen in the serum

A human prostate specific antigen (PA) has been purified from an extract of prostatic tissue obtained during operation for benign prostatic hypertrophy (BPH). The antigen, which can be demonstrated a single component by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), has an apparent molecular weight of about 34,000 and has lower mobility for the positive pole than prostatic acid phosphatase (PAP). Double antibody radioimmunoassay (RIA) for PA in serum was developed with the antiserum raised in rabbit against partially purified PA. In normal serum of 30 controls the concentration were studied by the RIA. The normal upper limit of the serum PA levels in assay was set at 2.5 ng/ml. Elevated levels were observed in serum from 19 out of 21 untreated patients with prostatic carcinoma and 9 out of 23 patients with BPH, but latter less than 10 ng/ml. The results indicate that the PA is a potentially useful marker as well as PAP for prostatic cancer.     

Enzyme-loaded liposome with biocatalytic precipitation for potentiometric immunoassay of thyroid-stimulating hormone in thyroid carcinoma

A simple and feasible potentiometric immunosensing platform based on enzymatic biocatalytic precipitation technique was designed for the sensitive detection of thyroid-stimulating hormone(TSH;a typical kind of biomarkers for thyroid carcinoma),using horseradish peroxidase(HRP)-loaded liposome for the signal amplification.To construct such an assay system,a sandwich-type immunoreaction was readily carried out on monoclonal anti-TSH capture antibody-coated electrode by using polyclonal antiTSH secondary antibody-conjugated HRP-loaded liposome.Accompanying the formation of sandwichtype immunocomplex,the carried liposome was lysed through the added Triton X-100 to release the entrapped HRP molecules,which catalyzed the oxidation of 4-chloro-1-naphthol to produce an insoluble and uncharged organic precipitation on the electrode surface,thereby causing the change of the local electrical potential.Two labeling protocols with and without the liposome were investigated for detection of target TSH,improved analytical features were achieved with HRP-entrapped liposome.Under optimal conditions,the potentiometric immunosensor had good responses for TSH detection within the linear range of 0.01-30 p IU/mL at a detection limit of 0.0067 p IU/mL.Good reproducibility,high specificity and long-time stability were acquired during the assay procedure.Importantly,a wellmatched accuracy between the potentiometric immunosensor and commercial human TSH ELISA kit was gave for the analysis of human serum samples.     

High-performance liquid chromatographic analysis of amphotericin B in plasma, blood, urine and tissues for pharmacokinetic and tissue distribution studies.

A sensitive and reproducible high-performance liquid chromatographic method was developed to assay ampherotericin B in plasma, blood, urine and various tissue samples. Amphotericin B was isolated from each sample matrix by solid-phase extraction (Bond-Elut). The eluate from Bond-Elut containing amphotericin B was injected onto a reversed-phase C18 column (Waters, mu Bondpak, 10 microns, 300 mm x 3.9 mm I.D.) with a mobile phase of 45% acetonitrile in 2.5 mM Na2EDTA at 1 ml/min. Detection of amphotericin B was by ultraviolet absorption at 382 nm. Blood and tissues were homogenized and extracted with methanol prior to Bond-Elut extraction. The extraction efficiencies of amphotericin B from plasma, blood and tissues were approximately 90, 70 and 75%, respectively. The sensitivity of the assay was less than or equal to 5 ng/ml for plasma, less than or equal to 25 ng/ml for blood, 2.5 ng/ml for urine and 50 ng/g for tissues. The linearity of the assay method was up to 2.5 micrograms/ml for plasma, 5 micrograms/ml for blood, 500 ng/ml for urine and 500 micrograms/g for tissues. The assay was reproducible with an intra-day coefficient of variation (C.V., n = 3) of less than 5% in general for plasma, blood and tissues. The inter-day C.V. of the assay was less than 5% for plasma (n = 5), less than 10% for blood (n = 4) and less than 5% for tissues (n = 3). The overall variability in the urine assay was generally less than 10%. This method has demonstrated significant improvement in the sensitivity and reproducibility in assaying amphotericin B in plasma and especially in blood, urine and tissues. We have employed this assay to compare the pharmacokinetic and tissue distribution profiles of amphotericin B in rats and dogs following administration of Fungizone and ABCD (amphotericin B-cholesteryl sulfate colloidal dispersion), a lipid-based dosage form. In addition, the assay method for plasma and urine samples can also be applied to pharmacokinetics studies of amphotericin B in man.     

An immunoradiometric assay for human follicle stimulating hormone using a monoclonal antibody coupled to magnetisable cellulose

A simple immunoradiometric assay for human follicle stimulating hormone (hFSH) was developed using a pair of monoclonal antibodies obtained from commercial sources. The system developed makes use of a capture antibody covalently coupled to magnetisable cellulose, which is a more economical and stable immunosorbent as compared to the other solid phases. The detector antibody is labeled with¹²⁵I using the chloramine-T oxidation method and purified by gel filtration. After initial cross-matching of the capture and detector antibodies, various assay parameters have been optimised. This assay does not show any significant cross reactivity with homologous hormones. A number of serum samples from men and women from reproductive age group was screened and compared with another commercially available kit (r=0.98). Sensitivity of the assay is 1.4 mIU/ml, interassay variation is <5% and intraassay variation around 15%. The assay is reproducible and sensitive enough for regular estimation of serum hFSH and is relatively inexpensive.     

Solid phase inclusive immunoradiometric assay for human chorionic gonadotropin using monoclonal antibodies

Summary A simple, one step, inclusive immunoradiometric assay for human chorionic gonadotropin (hCG) employing monoclonal antibodies is described. Commercially available monoclonal antibodies from various commercial sources were screened. Identified “detection” antibody was radiolabeled with ¹²⁵I and the selected “capture” antibody was chemically coupled to magnetizable cellulose to form a solid phase. In the procedure developed, standard/sample, radiolabeled antibody and capture antibody were incubated together for 3 hours at room temperature with shaking. After incubation, the bound complex was quantitated for the associated radioactivity. The analytical sensitivity observed was 1.0 mIU/ml with a wide concentration range up to 1000 mIU/ml of hCG. “High dose hook” of the developed assay was observed beyond 2000 mIU/ml. Results showed that the developed assay had a good precision: intra-assay CV less than 8%, inter-assay CV less than 10% and good analytical recovery of 97-109%. The clinical samples analyzed by the developed procedure showed a good correlation with that of the commercial kit (r = 0.92; y = 0.99x+0.51).     

Abnormal hepatobiliary clearance of 99mTc-N-(2,6-diethylphenylcarbamoylmethyl)iminodiacetic acid in the altered state of thyroid--by an analysis of deconvolution method

Hepatobiliary clearance of 99mTc-EHIDA was investigated in cases with altered thyroid function by deconvolution method. The results indicated that mean hepatic transit time of all control subjects revealed less than 10 minutes. On the other hand, mean hepatic transit time of cases with altered thyroid function revealed prolonged more than 13 minutes. Cases especially showing an elevated serum concentration of TSH compared with normal range (4.6 microU/ml) had a tendency of a high incidence of markedly prolonged mean hepatic transit time. These results suggest that thyroid hormone may influence on the hepatic metabolism of hepatobiliary radiopharmaceuticals. This phenomenon also could partly explain the cause of liver dysfunction seen in subjects with altered states.     

Enzyme Immunoassay of Thyroid-Stimulating Hormone Using Dried Blood Samples a Simple Technique of Screening for Congenital Hypothyroidism

Abstract

A method for enzyme imnunoassay of thyroid-stimulating hormone (TSH) in dried blood spotted onto filter paper has been developed. TSH was conjugated to horse-radish peroxidase according to Nakane's method. Separation of the bound and free fractions was obtained by a double antibody solid phase method using polyacetal beads which were coated with the purified IgG fraction from goat anti-rabbit IgG serum. p-Hydroxyphenyl propionic acid was used as substrate for the fluorophotometric assay of peroxidase activity. The assay sensitivity is 0.07, μU TSH/assay tube, which is equivalent to μU/ml when five 3 mm discs of dried blood spot are assayed. TSH values in dried blood samples obtained by this method correlate well with those of serum samples obtained by radioimmunoassay (r=0.89). The coefficients of variation were 6.8 to 13.4% (within assay) and 5 to 40% (between assay). The enzyme immunoassay of TSH presented here is applicable to the mass-screening for congenital hypothyroidism of neonate.     

Evaluation of radioimmunoassay of the blood tobramycin level for the purpose of setting the dosage based on the clinical pharmacokinetic theory and a comparison of radioimmunoassay with other assay methods

With the purpose to use for therapeutic drug monitoring (TDM), blood concentrations of tobramycin (TOB) in each patient were measured by radioimmunoassay (RIA). A RIA kit of TOB (Clinical assay-Japan Travenol) was evaluated for precision and recovery, in that partial improvement of the method was made, in order to measure low level of TOB. The RIA was compared with high-performance-liquid-chromatography (HPLC), bioassay (BA) and 2 kinds of enzyme immunoassay (EIA) (EMIT and SLFIA). The RIA of TOB revealed high precision (1.8-2.4% in C.V.) and high reproducibility (5.0-6.9% in C.V.). It was found that this RIA kit can be used for measuring low level of serum TOB concentrations by a modification of the method. The total range of measurable blood level is from 0.1 to 16.0 micrograms/ml. The nearly one to one correspondence was observed between RIA and other 4 methods, when 154 samples obtained from 18 cases were measured. A representative case of TDM for TOB was demonstrated, in which predicted concentrations agreed fairly well with actual measured values at steady state. It was concluded that the RIA kit is useful for clinical application of TDM for the adequate dosage regimen of TOB. Modification of the method for rapid assay of a small number of samples will increase the clinical usefulness.     

Clinical usefulness of a trypsin radioimmunoassay kit

From the clinical use of RIA-gnost trypsin kit, the following results were obtained. 1. Standard curve showed a steep and good curve was shown. 2. Incubation: The condition for the first incubation was set at the room temperature for 10-24 hours and that for the second incubation at the room temperature for 3-5 hours. With these settings, satisfactory results were obtained. 3. Reproducibility and recovery: The C.V. of the reproducibility and the recovery were considered superior, and the values were below 10% and +/- 3%, respectively. 4. Correlation between trypsin and serum elestase-1: An excellent positive correlation (coefficient of correlation r = 0.889) was shown. 5. Serum trypsin concentration of normal and pancreatic diseases: The normal range was from 100 to 500 ng/ml. Acute pancreatitis rose obviously. Diabetes mellitus and chronic pancreatitis was below 500 ng/ml and the pancreatic cancer showed a tendency to scatter in the range of 50-1,250 ng/ml. The above results indicated that serum trypsin can be easily measured with high precision by using this method. Thus the method is considered useful for the diagnosis of pancreatic diseases.     

Quantitative measurement of serum allergen-specific IgE on protein chip

Type I allergy is an immunoglobulin E (IgE)-mediated hypersensitivity disease inflicting more than quarter of the world population. In order to identify allergen sources, skin provocation test and IgE serology was performed using allergen extracts. Such process identifies allergen-containing sources but cannot identify the disease-eliciting allergenic molecules. Recently, microarray technology has been developed for allergen-specific IgE detection using rolling circle amplification. This study was carried out to evaluate protein chip technology for the quantitative measurement and limits of sensitivity of multiple allergen-specific IgE by an immunofluorescence assay. Significance of positive calibrators was tested using purified human IgE. Dermatophagoides pteronyssinus (Dp), egg white, milk, soybean, and wheat were used as allergens and human serum albumin as negative control. Sensitivity and clinical efficacy of protein chip were evaluated using allergy immune serum for Dp. The fluorescent intensities for purified human IgE as calibrator were well correlated with the concentrations of human IgE. Two-fold dilution of serum allowed an optimal reaction with Dp (1 mg/ml) at which serum Dp-specific IgE levels by protein chip were compatible with those by UniCap. The sensitivity of protein chip in this study was found at level of 1 IU/ml of IgE. Dp-specific IgE levels by protein chip correlated well with those of UniCap by comparing 10 atopic dermatitis. Additional 18 sera were tested for above multiple antigens other than Dp and significant results were obtained for many antigens as well as Dp. These results indicated that spotting of heterogeneous protein mixture on protein chip and the quantitative measurement of serum allergen-specific IgE levels using immunofluorescence assay can be successfully applied in the clinical laboratory for the diagnosis of allergy and could be applied to diagnosis of autoimmune and infectious diseases     

Highly Sensitive Sandwich Enzyme Immunoassay for Human Thyroid-Stimulating Hormone (hTSH) in Serum Using Monoclonal Anti-hTSH β-Subunit IgG1-Coated Polystyrene Balls and Polyclonal Anti-Human Chorinic Gonadotropin Fab′-Horseradish Peroxidase Conjugate

Abstract

A highly sensitive sandwich enzyme immunoassay for human thyroid-stimulating hormone (hTSH) in serum is described. Monoclonal anti-hTSH β-subunit IgG₁-coated polystyrene balls were incubated with serum samples and subsequently with polyclonal anti-human chorionic gonadotropin Fab¹-horseradish peroxidase conjugate. Neither hTSH nor anti-hTSH serum was required except for a small amount of hTSH as a standard. The detection limit of hTSH was 0.1 nU/tube or 0.005 mU/1 for most serum samples except for those from pregnant women, since there was no cross-reaction with 209 IU/1 of human follicle-stimulating hormone and 439 IU/1 of human luteinizing hormone when 20 μ1 of serum sample was used. Serum hTSH levels in normal subjects and Graves¹ disease were 1.22 ± 0.70 (SD) mU/1 (range: 0.26–2.65 mU/1) and 0.080 ± 0.062 (SD) mU/1 (range: < 0.005–0.17 mU/1), respectively.     

Radioimmunoassay of human growth hormone and its application in pituitary dysfunction studies

A simple, specific and sensitive Radioimmunoassay (RIA) has been developed for the measurement of Human Growth Hormone (HGH) in serum samples.¹²⁵I-labelled HGH has been used as a tracer and dextran coated charcoal system employed to separate antibody bound hormone from the unbound one. The assay offers sensitivity of 0.16 ng/ml with a reproductibility of 7% intrassay and inter-assay variations. Serum HGH levels were measured at fasting-resting state and during insulin stimulation test in (1) 15 normal subjects (controls and (2) 31 patients with stunted growth, whereas (3) in 7 acromegalic patients the same were measured at fasting-resting state and after oral glucose administration. This procedure has been used to distinguish dwarfs due to growth hormone deficiency from other conditions unrelated to pituitary disease and to confirm acromegaly.     

Analysis of lamotrigine and lamotrigine 2-N-glucuronide in guinea pig blood and urine by reserved-phase ion-pairing liquid chromatography.

Lamotrigine is an investigational anticonsulvant drug undergoing clinical trials. A simultaneous assay was developed to quantitate lamotrigine and its major metabolite, lamotrigine 2-N-glucuronide, from guinea pig whole blood. The extraction procedure and reversed-phase high-performance liquid chromatographic (HPLC) assay employed sodium dodecylsulfate (SDS) as an ion-pairing reagent to selectively separate lamotrigine and lamotrigine 2-N-glucuronide from endogenous blood components, other anti-convulsant drugs, and their metabolites. The mobile phase was composed of acetonitrile-50 mM phosphoric acid (pH 2.2) containing 10 mM SDS (33:67, v/v), and components were detected at 277 nm. The total coefficients of variance (C.V.) for the blood assay were less than or equal to 9.4% for lamotrigine (0.25-20.0 micrograms/ml) and less than or equal to 13.4% for the glucuronide metabolite (0.25-10.0 micrograms/ml). Separate assays for lamotrigine and its glucuronide in urine were developed. In order to quantitate low levels of lamotrigine in guinea pig urine, lamotrigine was extracted with tert.-butyl methyl ether-ethyl acetate (1:1). The total C.V. for lamotrigine quantitation in urine was less than or equal to 7.5% (0.10-10.0 micrograms/ml). For the determination of lamotrigine 2-N-glucuronide, urine was diluted with an SDS-phosphoric acid buffer (1:4) and injected directly onto the HPLC system, total C.V. less than or equal to 4.2% (0.5-50 micrograms/ml).     

Highly Specific and Sensitive Sandwich Enzyme Immunoassay for Human Thyroid-Stimulating Hormone (hTSH) in Serum Using Monoclonal Anti-hTSH β-Subunit IgG1-Coated Polystyrene Balls and Polyclonal Anti-hTSH β-Subunit Fab′-Horseradish Peroxidase Conjugate

Abstract

A highly specific and sensitive sandwich enzyme immunoassay for human thyroid-stimulating hormone (hTSH) in serum is described. Monoclonal anti-hTSH β-subunit IgG₁?coated polystyrene balls were incubated with serum samples and subsequently with affinity-purified polyclonal anti-hTSH β-subunit Fab′-horseradish peroxidase conjugate. There was no cross-reaction with 38 mIU/tube of human follicle-stimulating hormone, 40 mIU/tube of human luteinizing hormone or 10 IU/tube of human chorionic gonadotropin. The detection limit of hTSH was 0.3 nU/tube or 0.006 mU/1 of serum. Therefore, it was possible to measure very low levels of serum hTSH in pregnant women with Graves' disease. Serum hTSH levels in normal subjects and patients with Graves' disease were 2.45 ± 1.49 (SD) mU/1 (range : 0.61–6.09 mU/1) and 0.086 ± 0.060 (SD) mU/1 (range : < 0.006-0.18 mU/l), respectively. However, the present sandwich enzyme immunoassay was expensive, since affinity-purified polyclonal anti-hTSH β-subunit Fab′-peroxidase conjugate was prepared from rabbit anti-hTSH serum.