Survey Result of the Counting Efficiency of Gamma Counter by Certified Reference Materials / 대한핵의학회잡지

PURPOSE: In radioimmunoassay (RIA), the gamma counter is the important instrument for the accurate measurement. To manage quality assurance of RIA, the counting efficiency of gamma counter is one of the important parameters. The aimof this study was to evaluate the counting efficiency of gamma counters in multiple institutes on the base of traceability by using the certified reference materials (CRMs).METHODS: Twenty-three institutes that perform RIA were enrolled in this study. I-125 CRMs that were certified by National Institute of Standards and Technology (NIST) were used. Each institute was asked to count the activity of I-125 CRMs at most twice on all gamma counters in use. The counting efficiency of each well of counter was calculated on the base of NIST-certified information, corrected for I-125 decay for date of testing.RESULTS: From 23 institutes, 44 gamma counters were evaluated. The average counting efficiency of all wells was 85.9% and the standard deviation was 13.5%. As a mean value of each gamma counter, three gamma counters showed poor counting efficiency (less than 70%). The poorest counting efficiency was 7%. The counting efficiency of seven gamma counters was between 70 and 75%. Eight counters had the counting efficiency between 75 and 90%. More than half of counter (26 gamma counters) showed excellent counting efficiency (more than 90%). The standard deviation variation range of inter-well efficiency was from 0 to 11.2.CONCLUSION: The first survey on the counting efficiency of gamma counter was performed in South Korea. Most of the RIA laboratories have well managed the quality assurance of gamma counter.

Hepatitis B Surface Antigen Quantification across Different Phases of Chronic Hepatitis B Virus Infection Using an Immunoradiometric Assay

BACKGROUND/AIMS: Quantification of hepatitis B surface antigen (HBsAg) is an emerging serologic test and may be useful for identifying treatment strategies for chronic hepatitis B (CHB). This study aimed to evaluate HBsAg titers during the natural course of CHB and identify correlations between HBsAg titers and hepatitis B virus (HBV) DNA concentrations across different CHB phases measured using an immunoradiometric assay (IRMA). METHODS: CHB phases were defined on the basis of HBV DNA concentrations, the presence of hepatitis B e antigen/antibody (HBeAg/Ab) and serum alanine aminotransferase levels. Serum HBsAg titers and paired HBV DNA concentrations in the different phases of CHB were compared using 627 serum samples. RESULTS: Mean HBsAg titers were significantly higher in the immunotolerant (IT) phase and immunoreactive (IR) HBeAg-positive phase than in the low-replicative (LR) and HBeAg-negative CHB (ENH) states. The correlation between HBsAg titers and HBV DNA concentrations was modest in the IT (n=36, r=0.804, p<0.001) and IR (n=48, r=0.773, p<0.001) phases, and it was poor in the LR state (n=116, r=0.289, p=0.002); however, no significant correlation was observed in the ENH state (n=67, r=0.146, p=0.237) or in the oral nucleos(t)ide analogue-treated group (n=267). CONCLUSIONS: HBsAg quantification using IRMA might be useful for discriminating different CHB phases and different stages of chronic liver disease.

Valores de referência para níveis séricos do fator de crescimento semelhante à insulina tipo I (IGF-I) numa população adulta do Estado do Rio de Janeiro, Brasil / Reference ranges for serum levels of insulin-like growth Factor I (IGF-I) in an adult population of Rio de Janeiro State, Brazil

O nível sérico do Fator de crescimento semelhante à insulina tipo I (IGF-I) é fundamental para auxiliar no dignóstico e controle terapêutico dos transtornos relacionados à secreção do Hormônio de Crescimento (GH), bem como no diagnóstico e seguimento de outras doenças. Estabelecer valores de referência para as dosagens séricas de IGF-I por um ensaio imunoquimioluminométrico (ICMA), utilizando o sistema automatizado Immulite 2000/Diagnostic Products Corporation (DPC), e por um ensaio imunoradiométrico (IRMA), utilizando o kit comercial ACTIVE IGF-I/Diagnostic System Laboratories (DSL)-5600, numa população brasileira adulta da cidade do Rio de Janeiro. Este estudo, aprovado pelo Comitê de Ética do Instituto Estadual de Hematologia Arthur de Siqueira Cavalcanti, Rio de Janeiro, Brasil, incluiu amostras de 484 indivíduos saudáveis (251 homens e 233 mulheres) com idades entre 18 e 70 anos. As amostras foram estudadas por ICMA- Immulite 2000/DPC and IRMA- ACTIVE IGF-I/DSL-5600. Para análise dos dados foram utilizados modelos específicos para idade e sexo, após transformação dos dados de IGF-I. Foi observada uma lenta diminuição dos níveis de IGF-I com a idade usando ambos os ensaios. Os níveis de IGF-I foram signicativamente (p=0,0181) mais elevados em mulheres do que em homens, quando as amostras foram analisadas usando ICMA. Não houve diferença significativa dos níveis de IGF-I entre homens e mulheres quando as amostras foram analisadas usando IRMA. Este estudo estabeleceu valores de referência de IGF-I específicos para idade e sexo, determinados com o sistema automatizado ICMA-Immulite 2000/DPC, e valores de referência de IGF-I específicos para idade, determinados com o kit comercial IRMA- ACTIVE IGF-I/DSL-5600, em uma população adulta brasileira, da cidade do Rio de Janeiro

Serum level of insulin-like growth factor I (IGF-I) is fundamental in order to aid in the diagnosis and follow-up of growth hormone (GH)-related disorders, as well as in the diagnosis and follow-up of other diseases. The aim of this investigation was to determine reference values for IGF-I using an automated immunochemiluminometric assay (ICMA) system Immulite 2000/Diagnostic Products Corporation (DPC); and an immunoradiometric assay (IRMA), using the commercial kit ACTIVE IGF-I/Diagnostic System Laboratories (DSL)-5600, in an adult Brazilian population of Rio de Janeiro city. The study, approved by the Ethical Committee of the Instituto Estadual de Hematologia Arthur de Siqueira Cavalcanti, Rio de Janeiro, Brazil, included samples of blood taken from 484 healthy subjects (251men, 233 women) aged from 18 up to 70. The samples were analyzed by ICMA- Immulite 2000/DPC and IRMA- ACTIVE IGF-I/DSL-5600. For statistical analysis, age and sex-specific models were fitted after transformation of IGF-I values. In adulthood, a slow age-dependent decrease was found, using both assays. IGF-I in women were significantly (p=0,0181) higher than in men when samples were analayzed using ICMA.There was no significant difference between men and women IGF-I values when samples were analayzed using IRMA. The present study established age- and sex specific IGF-I reference values, determined with the automated system: ICMA-Immulite 2000/DPC and age-specific IGF-I reference values determined with the IRMA- ACTIVE IGF-I/DSL-5600, in an adult Brazilian population of Rio de Janeiro city

Determination of insulin-like growth factor-I reference values using an immunoradiometric assay in a Brazilian adult population.

Background: Serum levels of total insulin-like growth factor I (IGF-I) reflect endogenous growth hormone (GH) secretion in healthy adults, which makes it a good diagnostic marker for screening of GH-related disorders. Studies also have supported a possible relation between IGF-I levels and the risk and prognostic for some malignancies, besides a relation between IGF-I levels and mortality. Objective: As the determination of the IGF-I normal values for local populations is strongly desired, the aim of this investigation was to determine reference values for IGF-I using an immunoradiometric assay (IRMA) in an adult Brazilian population of Rio de Janeiro city, since there is no other study using this methodology in Brazilian population, and that this method is widely used in Brazil and worldwide. Materials and Methods: The study included samples of blood taken from 484 healthy subjects (251 men and 233 women) aged 18-70. The subjects agreed with this study, approved by the Ethical Committee of the Instituto Estadual de Hematologia Arthur de Siqueira Cavalcanti, Rio de Janeiro, Brazil. The samples were analyzed using a Diagnostic System Laboratories kit. For data analysis, age- and sex-specific figures were fitted after transformation of IGF-I values. Results: In adulthood, a slow age-dependent decrease was found. There was no significant difference in IGF-I values between men and women. Conclusion: This study established age-specific IGF-I reference values, for a healthy Brazilian adult population, determined by a widely IGF-I, IRMA used currently in Brazil.

Rapid one-step modified technique in the evaluation of thyroglobulin by the immunoradiometric assay (IRMA) for monitoring differentiated thyroid carcinoma patients.

Objective: The aim of this study was to develop a modified one-step technique for measuring serum thyroglobulin (Tg), which is currently used as a tumor marker for differentiated thyroid carcinoma (DTC) by using the immunoradiometric assay (IRMA) of the THYROGLOBULINE IRMA kit as compared with the standard method. Methods: The surplus serum specimens from 111 DTC patients who had been treated and followed up at the Division of Nuclear Medicine, Department of Radiology and 105 healthy donors at the Department of Transfusion Medicine, Faculty of Medicine, Siriraj Hospital were included. The technique for serum Tg measurement was optimized from the two-step IRMA standard kits to the one-step modified method. Results: The one-step modified technique results in a decrease of turnaround time (TAT) from two days of both one-step and two-step gold standard kits to only two hours. The optimal volume of 125I - TgAb was found to be the same that of the kit’s technique. The optimal time for incubation was decreased from overnight at 17-18°C in the standard method to 90 minutes in a shaking water bath at 37°C. The analytical and functional sensitivities of the modified technique were 0.28 and 1.0 ng/ml, respectively. The coefficients of variation (%CV) of both intra-assay and inter-assay precision were 0.87-4.80% and 2.87-9.75%, respectively. The accuracies of the recovery test and dilution test were 92.74-101.82% and 101.27-109.16%, respectively. No cross-reaction presented between the anti-thyroglobulin antibodies and thyroid analogue compounds. The assays working range of Tg concentration under 10% CV of precision profile was 1.59-500 ng/ml. The correlation coefficient (r) between the results of the modified technique and the two-step standard method were excellent: r = 0.99; y = 1.349x-2.421; P < 0.001; n = 111. The reference range of Tg concentration among the euthyroid healthy subjects was 0.37-20.32 ng/ml (5th -95th percentile). Conclusion: The modified technique is simple, rapid, sensitive and reliable for monitoring the serum Tg level in DTC patients not only under stimulation but also during suppression therapy.

Combined Determination of Serum PG and CEA and its Clinical Application in Distinctive Diagnosis of Benign and Malignant Gastric Ulcer / 中国基层医药

Objective The aim of this study was to evaluate the clinical value and the possibilities of measuring the serum levels of pepsinogen I (PG I ) and careineembryonic antigen (CEA) in 402 patients with gastric ulcer.Methods The patients with gastric ulcer were all confirmed by either operation or gastrofiberscope,and divided into two groups,benign and malignant gastric ulcer.After comparing the relationship between the patients'clinical appearance and the Radioimmunoaasay(RIA) results,(CEA and PG I ).Results There were 73 patients were onfirmed malignant gastric ulee in 402 patients.The positive rate of PG was 52.05% (38/73).The positive rate of CEA was 64.38% (47/73).Both were 30.14% (22/73).Then there were 63(63/73) patients who was positive in the combined determination.Solo determination's positive rate of CEA and PG were significantly different from the combined determination.(P＜0.05 and 0.01) Conclusions Feasibility and the necessity of combined determination were evaluated.Compared with solo determination,for patients with malignant gastric ulcer,it was more sensitive to determine and analysis the serum levels of PG I and CEA sYnthetically.So it is recommended to popularize the combined determination of serum PG I and CEA in clinical distinctive diagnosis of benign and malignant gastric ulcer.

Effects of Anti-thyroglobulin Antibody on the Measurement of Thyroglobulin: Differences Between Immunoradiometric Assay Kits Available / 대한핵의학회잡지

PURPOSE: Thyroglobulin (Tg) is a valuable and sensitive tool as a marker for diagnosis and follow-up for several thyroid disorders, especially, in the follow-up of patients with differentiated thyroid cancer (DTC). Often, clinical decisions rely entirely on the serum Tg concentration. But the Tg assay is one of the most challenging laboratory measurements to perform accurately owing to antithyroglobulin antibody (Anti-Tg). In this study, we have compared the degree of Anti-Tg effects on the measurement of Tg between availale Tg measuring kits. MATERIALS AND METHODS: Measurement of Tg levels for standard Tg solution was performed with two different kits commercially available (A/B kits) using immunoradiometric assay technique either with absence or presence of three different concentrations of Anti-Tg. Measurement of Tg for patient's serum was also performed with the same kits. Patient's serum samples were prepared with mixtures of a serum containing high Tg levels and a serum containg high Anti-Tg concentrations. RESULTS: In the measurements of standard Tg solution, presence of Anti-Tg resulted in falsely lower Tg level by both A and B kits. Degree of Tg underestimation by A kit was more prominent than B kit. The degree of underestimation by B kit was trivial therefore clinically insignificant, but statistically significant. Addition of Anti-Tg to patient serum resulted in falsely lower Tg levels with only A kit. CONCLUSION: Tg level could be underestimated in the presence of anti-Tg. Anti-Tg effect on Tg measurement was variable according to assay kit used. Therefore, accuracy test must be performed for individual Tg-assay kit.

Influence of Anti-thyroglobulin Antibody on the Measurement of Thyroglobulin using the Immunoradiometric Assay / 대한내분비학회지

BACKGROUND: Serum thyroglobulin(Tg) is a valuable and sensitive tool needed in the follow-up of patients with differentiated thyroid cancer(DTC), but antithyroglobulin antibody(Anti-Tg), common in patients with DTC, can interfere with the assay for Tg. In this study, we evaluated the influence of Anti-Tg on the measurement of Tg using the immunoradiometric assay(IRMA). METHODS: In using ELSA-hTg in vivo test(CIS international, Schering, France), a solid phase two-site IRMA was used to measure Tg(23.5ng/mL, 62.5ng/mL) under the absence or presence of three concentrations of Anti-Tg(25U/mL, 50U/mL, 100U/mL). We also performed Tg measurement using patients serum that was mixed with patients serum containing high Anti-Tg. ANOVA and Scheffe tests were performed to evaluate the effect of Anti-Tg on Tg IRMA, and an inverse regression was made to calculate the level of Tg from measured Tg and used Anti-Tg levels and also to assess the degree of effect of anti-Tg on Tg IRMA. RESULTS: In measuring Tg using the standard solution, the presence of Anti-Tg resulted in a falsely suppressed Tg value. The IRMAs for 23.5ng/mL of the standard Tg solution resulted in 24.5+/-.1 ng/mL under no Anti-Tg, 11.8+/-.4ng/mL under 25U/mL of Anti-Tg, 7.7+/-.1ng/mL under 50U/mL of Anti-Tg, and 4.5+/-.4ng/mL under 100U/mL of Anti-Tg. IRMAs 62.5ng/mL of the standard Tg solution resulted in 65.9+/-.7ng/mL under no Anti-Tg, 36.3+/-.2ng/mL under 25U/mL of Anti-Tg, 23.7+/-.7ng/mL under 50U/mL of Anti-Tg, and 14.0+/-.0ng/mL under 100U/mL of Anti-Tg. (ANOVA test, p=0.000). The degree of suppression of the measured Tg value was positively correlated with the Anti-Tg level (Quadratic model regression, Sig T=0.000). The presence of Anti-Tg also resulted in a falsely suppressed Tg value for the Tg measurement using patient's serum. CONCLUSION: The presence of Anti-Tg could consist of the use of Tg as a tumor, therefore Anti-Tg should be measured in all patients diagnosed with DTC. The interpretation of the Tg level must be performed with extreme caution in patients with Anti-Tg.

Estado actual y perspectiva de las pruebas relacionadas con el estudio de la función tiroidea / Present state and prospects of tests related to the thyroid function study

Las enfermedades tiroideas pueden ser diagnosticadas, en la mayoría de los casos, por la clínica. Sin embargo, existen situaciones que requieren de las pruebas de función tiroidea con el fin de valorar correctamente al paciente en las etapas iniciales de la disfunción de esta glàndula, con el fin de establecer el tratamiento adecuado de forma individual y el seguimiento de la evolución de la enfermedad. En esta revisión hacemos referencia a las pruebas empleadas para valorar el estado de la función tiroidea y se señalan sus ventajas, limitaciones y tendencias actuales. La determinación de TSH por procederes de segunda y tercera generaciones permite establecer el diagnóstico del hipertiroidismo e hipotiroidismo primarios, aún en las formas subclínicas de ambos, al mostrar inhibición o hipersecreción, respectivamente, así como la dosis adecuada de l-levotiroxina y orientar a una causa hipofisaria de esta disfunción. La determinación de T4 es de gran valor para conocer la intensidad de la disfunción tiroidea y para valorar la eficacia del tratamiento en las primeras semanas de iniciado. La determinación de T3 tiene su principal indicación ante la sospecha de la presencia del llamado hipertiroidismo por T3. La determinación de T4 y T3 totales da lugar a una interpretación incorrecta en cuanto a las situaciones que modifican la globulina transportadora de tiroxina (TBG). La tendencia actual es al empleo de TSHs como prueba inicial para el diagnóstico de la disfunción tiroidea, la cual se debe indicar teniendo siempre en cuenta la clínica y, de ser necesario, asociarla a la determinación de T4 o T3 libres(AU)

The thyroid diseases may be diagnosed in most of cases by the clinics. However, there are circumstances that required thyroid function tests to correctly assess the patient in initial stages of thyroid dysfunction and give an adequate treatment on an individual basis and the follow-up of the disease. This review makes reference to the tests used to assess the condition of the thyroid function and mentions their advantages, limitations and present trends. The determination of TSH by second and third generation procedures allow setting up diagnoses of primary hyperthyroidism and hypothyroidism, even in the subclinical forms of both entities since or hypersecretion or inhibition are respectively exposed, and they also allow prescribing the right dose of 1-Levothyroxine and orienting towards a hypophyseal cause of thyroid dysfunction. T4 determination is of great value for finding out the intensity of thyroid dysfunction and furthermore assessing the effectiveness of the treatment in the first weeks. T3 determination is mainly indicated when the so-called T3-caused hyperthyroidism is suspected. The determination of total T4 and T3 gives rise to a wrong interpretation regarding the conditions that change the thyroxine-transporting globulin (TBG). The present trend is the use of TSH as an initial test for diagnosing the thyroid dysfunction, which should be indicated taking the clinic into account, and if necessary, it should be associated with the determination of free T4 or free T3(AU)

The determination of parathyroid hormone in the chronic renal failure and its clinical significances / 医学研究生学报

The secondary hyperparathyroidism is one of the complications of chronic renal failure (CRF) and end stage renal failure (ESRD), and becomes more serious with the development of the primary disease. Parathyroid hormone (PTH) is considered as one of the biomarks of the development of renal failure. The purpose of this article will expound the physiological effects of the PTH, the causes and clinical significances of PTH rising in CRF and ESRD patients, the determination of PTH level, and the relationships between the increase of PTH and the polymorphism of CYP2D6, GSTT1,GSTM1.

Establishment and application of immunoradio assay for detecting human soluble IL-6R? / 中华检验医学杂志

Objective To establish the sensitive,specific,stable and convenient immunoradio assay for detecting human soluble IL-6R?.Methods The hybridoma cell lines were obtained by fusing spleen cells of BALB/c mice that had been immunized with soluble IL-6R? protein to mouse myeloma cells sp2/0. Ascites were used to produce the monoclonal antibodies (mAbs). The mAbs were purified by protein G immunoaffinity method. The mAb SI10 was used as coating antibody, the other mAb H126 recognized different epitope from SI10 was labeled by 125I. Results The immunoradio assay for detecting soluble IL-6R? was set up. It has high stability and accuracy. The detecting limit is 10 ng/ml. The serum concentration of soluble IL-6R? is (81.96 ? 7.23) ng/ml in healthy donors and (237.58?70.96) ng/ml in patients with multiple myeloma. Significant difference was founded between two groups (P

The Evaluation of Domestic Immunoradiometric Assay Kit for Alpha-fetoprotein / 대한핵의학회잡지

PURPOSE: Although alpha-fetoprotein is one of the most commonly used tumor markers in Korea, most of the radioimmunoassay kits for alpha-fetoprotein have been imported from foreign countries. The purpose of this study was to evaluate the performance of a recently developed domestic immunoradiometric kit for alpha- fetoprotein (Riakey AFP IRMA CTR, Sin-Jin Medics, Seoul, Korea). MATERALS AND METHODS: We evaluated intra- and inter-assay precision, recovery rate, parallelism, and sensitivity of serum alpha-fetoprotein measurement using Riakey AFP IRMA CTR kit. The values of alpha-fetoprotein measured by Riakey AFP IRMA CTR kit were compared with those measured by two foreign commercial kits (alpha-fetoproteina of Radim and alpha-feto.riabead of Abbott). RESULTS: Intra-assay coefficients of variation on three different levels were 5.3% for 18.9 ng/ml, 3.4% for 133 ng/ml and 1.6% for 330 ng/ml. Inter-assay coefficients of variation were 9.7% for 20.9 ng/ml, 3.2% for 137 ng/ml and 4.1% for 330 ng/ml respectively. Recovery rate tests on all three different levels showed within 100+/-10%. Parallelism was also good and the sensitivity was 0.63 ng/ml. There was strong correlation between the measurement of alpha-fetoprotein by Riakey AFP IRMA CTR and that by two foreign commercial kits(r=0.98). CONCLUSION: The first Korean domestic immunoradiometric kit for alpha-fetoprotein, Riakey AFP IRMA CTR, performed well for clinical use.

CEA and CA19-9 in the Tissue, Portal, and Peripheral Blood of Gastric Cancer Patients

BACKGROUND: To clarify the clinical significance of CEA and CA19-9 in patients with gastric cancer, we evaluated the correlation between tissue expression, the peripheral and the portal levels of these tumor markers, and ten clinicopathological factors, as well as the prognosis. METHODS: Surgical specimens from 40 patients with gastric cancer were examined by using immunohistochemical staining with anti-CEA and anti-CA19-9 monoclonal antibodies. Serum levels of CEA and CA19-9 in the portal and the peripheral blood were measured by using immunoradiometric assays. RESULTS: Positive values of the portal venous CEA were more common in patients with lymph-node metastasis, distant metastasis, and lymphatic invasion than in those without these factors. Curative surgery was performed in 50.5% of the patients with high portal CEA levels and in 90.6% of the patients with low portal CEA levels. Positive values of the peripheral venous CEA were significantly higher in cases with lymph-node metastasis. The positive rate of CA19-9 immunohistochemistry was significantly higher in patients with distant metastasis and in non-curative surgery. The positive rate of peripheral venous CA19-9 was higher in cases with distant metastasis. The three-year survival rate of patients with negative tissue CEA was significantly higher than that of patients with a positive result. The peripheral venous levels of CEA and CA19-9 reflected the portal venous levels accurately. CONCLUSIONS: These results suggest that immunohistochemical examination of CEA in patients with gastric cancer is useful for the evaluation of the biological aggressiveness and progression of the disease and can be used for making a prognosis.

Production of tumor necrosis factor-alpha by alveolar macrophages from patients with pulmonary tuberculosis

In order to ascertain the role of TNF-alpha in pulmonary tuberculosis, we determined the TNF-alpha productivity of alveolar macrophages(AMs) obtained by bronchoalveolar lavage(BAL), along with the level of TNF-alpha in the serum of patients with tuberculosis including pulmonary, miliary, and endobronchial tuberculosis, healthy controls, and pulmonary diseases such as diffuse interstitial lung disease (DILD) and pneumonia. AMs from patients with pulmonary tuberculosis did not produce a larger amount of TNF-alpha than did those from the healthy control subjects. However, among the patients with pulmonary tuberculosis, the AMs from the fresh and reactivated groups produced a larger amount of TNF-alpha than those from the inactive group. AMs from patients showing positivity in culture produced a larger amount of TNF-alpha than those showing negativity. The average level of serum TNF-alpha in patients with pulmonary tuberculosis was slightly higher than that of the healthy control group. Among patients with pulmonary tuberculosis, significantly increased levels of serum TNF-alpha were noted in the reactivated group compared to those of the fresh and inactive group. Patients with moderate to far-advanced infiltration on their chest X-rays, showed a significantly higher level of serum TNF-alpha than those with minimal involvement on the chest X-ray. Smokers from the healthy control group showed a significantly higher level of serum TNF-alpha than non-smokers from the same group. These results suggest that an increase in the production of TNF-alpha may correspond with the severity of pulmonary tuberculosis.

Immunoradiometric assay of human proinsulin and partially processed proinsulin with use of monoclonal antibody and streptavidin-biotin labeling

The sensitive and specific immunoradiometric assay is described for human proinsulin and its intermediate peptides (65-66 split and 32-33 split proinsulin). We developed a monoclonal antibody-based two-site immunoradiometric assay with use of streptavidin-biotin labeling. The detection limits of the assays lie in the range of 0.5-2.0 pM. In the proinsulin assay proinsulin cross-reacted 66% with 65-66 split proinsulin but not with insulin or 32-33 split proinsulin. In the assay of 65-66 split proinsulin it does not cross-react with insulin, proinsulin or 32-33 split proinsulin. In the 32-33 split proinsulin assay it cross-reacted 84% with proinsulin and 60% with 65-66 split proinsulin. The precision (C.V.) of the assays was less than 15% over the various concentration. The mean concentrations of insulin, proinsulin, 65-66 split proinsulin and 32-33 proinsulin in eight young male subjects in the fasting state were (pM +/- S.E.M.) 20 +/- 3.6, 2.3 +/- 0.3, undetectable (less than 1.0) and 2.1 +/- 0.7 and at the maximum reached during an oral glucose tolerance test, 150 +/- 26, 9.9 +/- 1.4, 3.8 +/- 0.6 and 19.7 +/- 6.0 respectively.

THE DEVELOPMENT OF IMMUNORADIOMETRIC ASSAY OF HUMAN GROWTH HORMONE IN URINE AND ITS CLINICAL APPLICATION / 中华内分泌代谢杂志

A specific solid-phase immunoradiometric assay (IRMA),optimized for maximal sensitivity, has been developed for measurement of human growth hormone in urine. One monoclonal antibody was iodinated using modified Ch-T method, another was linked to CNBr activated Sepharose-4B. The assay sensitivity was 125 pg/L: Intra- and inter-assay variation were 3.8%, 5.19% respectively. The dilution test and the recovery test were satisfactory. This assay is not influenced by the changes of following conditions: pH(5.0- 7.4), 0-0.25 mol/L sodium chloride and 0-0.5 mol/L urea. The GH values in the urine of 10 hours at night in healthy young males (n=9), females (n = 9), patients with acromegaly (n = 9), and patients with complete GH deficiency(n = 8) were 0.55 ?0.50 ng, 0.44 ?0.33 ng, 58.07?35.90 ng, and unde-tectable, respectively. In young males and females, the urinary GH values were not significantly different, while in patients with acromegaly, the urinary GH values were significantly different from that in normal adults(P