Sensitive Radioimmunoassay Technique Research Articles

Murine mammary tumor virus deficient in the major glycoprotein: Biochemical and biological studies on virions produced by a lymphoma cell line

A cell line, designated MLA, was established from a spontaneous lymphoma of a DBA/2 mouse. These cells contained large amounts of intracytoplasmic type-A particles, the presumed precursors of mature MuMTV. Electron microscopy revealed that the MLA cells released MuMTV-like virions into the culture fluid, but these virions were devoid of the characteristic envelope “spikes” of MuMTV. Antigenic analysis of virions purified from the culture fluid of MLA cells showed that, by microimmunodiffusion, the glycoproteins of MuMTV, gp49 and gp36, were not detectable, nor was the glycoprotein gp70 of MuLV detectable. Internal structural proteins of MuMTV, p28 and p12, were however, readily detectable in these virions. By the more sensitive radioimmunoassay technique, it was found that the virions produced by MLA cells contained some gp49-related antigen, but the amount present was about 500-fold lower than in other tissue culture-derived MuMTV. MLA cells synthesized a 70,000-dalton precursor of MuMTV glycoproteins. Culture fluids from which the virions were removed by centrifugation did contain gp49, indicating processing of the precursor polypeptide, but this polypeptide was not incorporated into the virions. Molecular hybridization studies revealed that MLA cells contained a large amount of MuMTV-specific RNA; the amount of MuLV-related RNA was about 100-fold lower. Whereas 150–200 MuMTV particles were released into culture fluid per cell per day, few MuLV particles were released. Purified virions from the MLA cells were injected into BALB/c and C57BL weanling females. This resulted in mammary tumor development in BALB/c females, but not in C57BL. The tumors contained MuMTV with the normal complement of envelope spikes and gp49 was detectable in the virions.

Use of immunoglobulin M antibody to hepatitis B core antigen in diagnosis of viral hepatitis

To determine the diagnostic value of hepatitis B core (HBc)-specific immunoglobulin M (IgM) antibody (anti-HBc IgM), the sera of six patients with known recent acute viral hepatitis B were examined for the presence of anti-HBc periodically for up to 21 months from the onset of the attack by a sensitive radioimmunoassay technique (CORAB, Abbott Laboratories). It was found that anti-HBc IgM was detectable for approximately 17 months from the onset of the illness. Hence the finding of anti-HBc IgM suggests infection by hepatitis B virus, probably within the preceding 1 to 2 years. A high level of anti-HBc IgM in the acute-phase serum of an individual with viral hepatitis is indicative of recent hepatitis B virus etiology; one patient, however, showed a low titer of anti-HBc IgM in the acute-phase serum sample, which remained virtually unchanged 15 months from onset. The diagnostic use of this serologaical marker is illustrated in 25 patients with viral hepatitis, in whose acute-phase sera anti-HBc was found.

Rapid release of fibronectin from human lung fibroblasts by biologically active phorbol esters

A sensitive radioimmunoassay technique has been used to study the effects of several phorbol esters on their ability to release fibronectin from cultured human lung fibroblasts into medium. The biologically active phorbol esters studied rapidly released fibronectin from cells into medium, with concomitant changes in the cellular morphology within 2 h. The quantity of fibronectin released was dose-, time- and promoter-dependent. The earliest release of fibronectin was seen within 30 min of onset of the incubation. Alterations in membrane topology elicited by phorbol esters appear to be responsible for the rapid release of fibronectin molecules from cells into the medium.

The effect of hypothalamic lesions on immuno-reactive alpha-melanocyte stimulating hormone secretion in the rat.

We have examined the hypothesis that MSH secretion in the rat is under a tonic inhibitory control by the central nervous system. Electrothermic lesions were made in the medio-basal hypothalamus (m.b.h.) which destroyed the hypothalamo-hypophyseal connexions. Plasma and pituitary alpha-MSH wwere measured using a sensitive and specific radioimmunoassay technique. Pituitary alpha-MSH content decreased to 17% of control levels 24 hr after the lesion and returned to normal by 7 days. Plasma alpha-MSH was maximally elevated 15 min after the lesion, and returned to normal by 2 hr. No further change over control levels was found for the remainder of the experiment (98 days). The similarity of the plasma alpha-MSH response after m.b.h. lesions to that found previously after administration of long acting dopamine receptor blocking drugs suggests that these lesions may interrupt impulse flow in dopaminergic tubero hypophyseal neurones which are thought to be important in the inhibitory control of MSH secretion in the rat. From our present results it seems that the rat pituitary, unlike that of lower vertebrates, is able to re-establish basal MSH secretion very quickly after disconnexion from central control.

HBeAg and anti-HBe detection by radioimmunoassay: correlation with vertical transmission of hepatitis B virus in Taiwan.

A sensitive radioimmunoassay technique was used to detect hepatitis B e antigen (HBeAg). A strong correlation was found between HBeAg positivity of the serum of hepatitis B surface antigen (HBsAg) carrier women in Taiwan and the subsequent development of surface antigenemia in their babies. All babies who became chronic HBsAg carriers were born to HBeAg positive women, maternal HBeAg positivity being a better prior indication of chronic antigenemia developing in the baby than the HBsAg titer in the mother's serum.

Simplified Radioimmunoassay for Detection of Human Rotavirus in Stools

A simplified radioimmunoassay (RIA) technique was developed to facilitate the diagnosis of human rotavirus in stools of infants with diarrhea. This microtiter solid-phase RIA utilizes as a critical reagent hyperimmune serum against a tissue culture-grown simian rotavirus that is immunologically closely related to the human agent. One hundred thirteen pediatric stool samples were tested. Thiry-five specimens known to be positive for rotavirus by electron microscopy were also positive by RIA. All RIA-positive reactions (36) were shown to be specific for rotavirus by means of an antibody-blocking test. Nonspecific RIA-positive reactions were not encountered. This accurate, sensitive RIA technique is practical for use in diagnostic laboratories because critical serum reagents are prepared against culture-grown virus and not against rotavirus derived from carefully selected stools of humans or experimentally infected gnotobiotic animals.

A highly sensitive radioimmunoassay technique for subtyping the antibody to hepatitis B surface antigen

A highly sensitive technique for determinig the subtype specificity of antibody to hepatitis B surface antigen (anti-HBs) is described. Immunoadsorbent consisting of controlled pore glass coated with subtype specific HBsAG was used to remove homologous antibody from the test samples before testing them for residual antibody by a commercially available radioimmunoassay (RIA). A total of 73 anti-HBs-positive samples from asymptomatic blood donors were tested. In nearly 80% of these samples the subtype reactivity could be determined by this technique. Only 67% could be typed by conventional liquid phase absorption RIA and 22% by passive hemagglutination inhibition techniques. Among the samples with low anti-HBs titer, ad and ay subtypes were found with equal frequency; however, with the increase in anti-HBs titer, considerably higher proportion of ad specificity was detected.

Radiochemical Characterization of Hemoglobins Lepore and Kenya: Unique Antigenic Determinants Located on Hybrid Hemoglobins

Abstract Antisera were produced in rabbits to the three known types of Lepore hemoglobins, which contain hybrid δ-β non-α-chains, and to hemoglobin Kenya, which has a hybrid γ-β non-α-chain. By using a sensitive radioimmunoassay technique, the absorbed antisera were shown to contain an antibody population that was specific for the hybrid hemoglobin and did not cross-react with normal hemoglobins. However, with the absorbed Lepore-specific antisera, the three known types of Lepore hemoglobins were antigenically indistinguishable from each other, suggesting that antibodies are not produced to the primary structural differences which define the three non-α-chains of the Lepore hemoglobins. These studies demonstrate that the non-α-subunits of hemoglobins Lepore and Kenya possess unique antigenic determinant sites, evidently resulting from an altered polypeptide conformation.

Inhibition of prostaglandin synthesis by indomethacin augments the renal vasodilator response to bradykinin in the anesthetized dog.

It has been proposed that the increase in renal blood flow (RBF) produced by bradykinin (BK) is mediated or amplified by the intrarenal generation of prostaglandins. The present investigation was designed to explore these relationships further. In anesthetized dogs, the renal arterial infusion of BK (100 ng/kg per min), prior to the intravenous administration of indomethacin, produced a 93 +/- 14% increase in RBF and an increase in the renal venous concentration of a prostaglandin E-like substance ("PGE") from 51 +/- 23 to 235 +/- 73 pg/ml as determined by bioassay. Following indomethacin (5 mg/kg), the same dose of BK produced a 151 +/- 18% increase in RBF (P less than 0.001 compared to the preindomethacin increase) and the concentration of "PGE" remained largely below the threshold of sensitivity of the bioassay system. In three experiments, a highly sensitive and specific radioimmunoassay technique was used to obtain better quantitative estimates of concentrations of E2-like ("PGE2") and F2alpha-like ("PGF2alpha") substances so that determinations of renal efflux could be made. Thus, prior to indomethacin, BK administration increased RBF by 142 +/- 39 ml/min and was associated with a 26-fold increase in renal efflux of "PGE2" and a 12-fold increase in "PGF2alpha." After indomethacin, the effluxes of both "PGE2" and "PGF2alpha" decreased to negligible levels and were not influenced by BK infusion, although RBF increased by 225 +/- 75 ml/min. These results are not compatible with the hypothesis that intrarenal prostaglandins mediate or amplify the renal vasodilator response to BK.

Serological evidence of hepatitis B infection in patients with chronic liver diseases: radioimmunoassay of HBsAg and anti-HBs.

The prevalence of hepatitis B surface antigen (HBsAg) and anti-HBs was determined by a sensitive double-antibody radio-immunoassay technique in a series of patients with chronic liver diseases. HBsAg was demonstrated in 37 out of 98 consecutive patients with chronic hepatitis (38%) and in 14 out of 108 patients with non-alcoholic cirrhosis (13%). HBsAg was not found in any of the patients with steatosis, alcoholic cirrhosis, or primary biliary cirrhosis. In the patients with chronic hepatitis HBsAg or anti-HBs was demonstrated in 83% of the patients below 40 years of age in contrast to 48% of the patients more than 40 years of age. It is concluded that a substantial part of the patients with chronic hepatitis has serological evidence of actual or past hepatitis B virus infection. This is in contrast to the groups of patients with other chronic liver diseases.

The effect of orciprenaline sulphate on the in vitro production of prostaglandins E and F by the guinea pig uterus

The effect of orciprenaline sulphate on the in vitro production of PGs E and F by guinea pig uterine tissue homogenates has been investigated. Estimations of PGs were carried out using sensitive radioimmunoassay techniques. The results indicate that orciprenaline can effectively reduce the in vitro yield of PGs E and F from guinea pig uterine tissue. This could in turn be due to an inhibitory effect of orciprenaline on PG formation or due to stimulation of PG breakdown by the drug. The implications of these results in relation to premature labour are discussed.

Review: human prolactin--recent advances in physiology and therapy.

Summary: Human prolactin has been proven to exist as a unique hormone of the anterior pituitary gland. Use of sensitive bioassay and radioimmunoassay techniques has enabled it to be measured in serum and amniotic fluid. Serum prolactin values increase in some women during the luteal phase of the menstrual cycle, in all women during pregnancy and during postpartum suckling. High concentrations of this hormone are also found in amniotic fluid and in neonates for the first few weeks of life. Unlike most other pituitary hormones, prolactin is normally under inhibitory control from the hypothalamus and various stimulatory and inhibitory tests have been used to test the integrity of this hypo‐thalamic‐pituitary axis. Such tests have been used in clinical conditions where abnormally high serum prolactin levels, or hyperprolactinaemia, have been found in an attempt to localize the disorder and explain its pathogenesis. Hyperprolactinaemia is common in secondary amenorrhoea and galactorrhoea, or inappropriate lactation, and should be excluded in all patients presenting with these problems. It also occurs frequently in patients with pituitary tumours and may cause the reduced libido and impotence in some men complaining of infertility. Drug therapy is now available to suppress serum prolactin concentrations and has been used successfully to prevent or suppress puerperal lactation. Pathological states, such as hyperprolactinaemic secondary amenorrhoea and galactorrhoea have also been treated with these drugs with lowering of serum prolactin values to the normal range and subsequent restoration of ovulation and fertility, or cessation of lactation. A policy for the diagnosis, investigation and clinical management of such patients is presented.

Evaluation of Visceral Larva Migrans by Radioimmunoassay Systems

A 9-year-old child with miliary pulmonary infiltrates, eosinophilia, and hyperimmunoglobulinemia E recovered rapidly cover a four-week period. Subsequent analysis of serum samples by a solid phase radioimmunoassay technique demonstrated IgM, IgE, and IgG antibodies to Ascaris suum antigen which declined following the acute phase of the illness in parallel with a decline in serum IgM, IgE, and IgG concentrations. Precipitating antibodies in serum against Ascaris antigen were demonstrated. The diagnosis is considered to be toxocariasis or ascariasis. The application of sensitive radioimmunoassay techniques of this type should provide a method of earlier diagnosis and the demonstration of rapidly changing antibody levels a method of confirming the diagnosis in parasitic diseases.

The inhibition of the primary interaction between 1 2 5I-labeled human hemoglobin and rabbit anti-human hemoglobin sera: A sensitive radioimmunoassay technique

A rapid and sensitive radioimmunoassay technique for hemoglobin based upon a modification of the Farr test is described. Since hemoglobin is soluble in ammonium sulfate whereas antibody is precipitated, the amount of free and antibody-bound radiolabeled human hemoglobin can be quantitatively measured after ammonium sulfate precpitation. Nanogram quantities of hemoglobin can be detected by the addition of unlabeled human hemoglobin to the antiserum before the labeled hemoglobin, thus establshing a competition reaction between labeled and unlabeled antigen for antibody. If sufficient quantities of unlabeled human hemoglobin are present, all of the antibody combining sites become saturated and the primary interaction between 1 2 5I-labeled hemoglobin and antibody is completely inhibited. The method can be employed to discriminate various normal human hemoglobins, non-human primate hemoglobins as well as sickle-cell hemoglobin (HbS). Other possible applications of the technique are discussed.

Circulating concentrations of dehydroepiandrosterone and dehydroepiandrosterone sulfate during puberty.

In order to quantitate the chronological change in circulating dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DS) levels during the period of sexual maturation, serum DHEA and DS concentration (3-5 PM) in 76 boys and 65 girls (ages 8 to 15) as well as in adult male and female subjects were measured by a specific and sensitive radioimmunoassay technique. Our data show a progressive and parallel increase in serum DHEA and DS concentrations in boys, and adult male levels were reached earlier for DHEA (age 13) than for DS (age 14). From age 8 to adult male, there was a 2.6-fold increase in DHEA (1.52 plus or minus 0.16 ng/ml to 3.91 lus or minus 0.34 ng/ml) and a 7.7-fold increase in DS (0.40 plus or minus 0.08 mug/ml to 3.09 plus or minus 0.36 mug/ml). The rise of DHEA and DS was not in a parallel fashion in girls; while DS rose progressively, DHEA showed an abrupt increase between 11 and 12 yr of age. Adult female range was reached by age 12 for DHEA and by age 15 for DS. From age 8 to adultfemale there was a 2.3-fold increase in DHEA (1.93 plus or minus 0.19 ng/ml to 4.49 plus or minus 0.76 ng/ml) and a 7.5-fold increase in DS (0.29 PLUS OR MINUS 0.05 MUg/ml to 2.17 plus or minus 0.34 mug/ml). The role of increased adrenal androgens inthe sexual development during early stages of puberty is discussed.

Serum concentrations of β-melanocyte-stimulating hormone in human pregnancy

β-Melanocyte-stimulating hormone (β-MSH) has been measured in pregnant women with the use of a sensitive tube radioimmunoassay technique which does not require prior extraction. This peptide rises progressivley throughout pregnancy with its highest concentration at term. Measurable quantities exceeding maternal levels were observed in both cord blood and amniotic fluid and elevated levels of β-MSH were found in lactating women. The role and possible chorionic origin of β-MSH remain to be determined, as well as the possible clinical use.

Recent Advances in Detection and Treatment of Urological

Alpha fetoprotein (AFP) at a level of 250 times its very low normal level in adults is characteristic or diagnostic of hepatoma or teratoma one of which is testicular tumor. Immunochemical methods are used for AFP detection. 75% of a review series were found positive for AFP using autoradioautography; with newer more sensitive radioimmunoassay techniques as many as 85% should be diagnosed. The clinical applications of positive AFP determinations include ruling out of simple epididymo-orchitis and assigning of an anaplastic tumor to the teratoma series. To date no attempt to study the prognostic value of positive AFP in testicular tumors has been reported but in an informal presentation of personal cases 11/17 positive AFPs were anaplastic tumors; of 8 deaths 7 were positive for AFP suggesting a poorer prognosis if AFP is present. AFP level determination will help in treatment selection for if a patient has a positive AFP before orchidectomy and it remains elevated after then there must be metastases.

Hormone patterns in early human gestation.

Accurate measurement of the low concentration of gonadotropins and steroid hormones present in human serum has been made possible by the development of sensitive radioimmunoassay (RIA) techniques; With the use of RIA FSH and LH, progesterone and 170H-progesterone have been previously measured in early normal pregnancy (Jaffe et al., 1969; Parlow et al., 1970; Wide, 1969). In order to determine the daily pattern of hormone levels in early normal pregnancy, gonadotropins as well as steroid hormone levels were measured in serum samples obtained daily from three women from the time of the last menstrual period prior to conception throughout the first few months of gestation.KeywordsEarly PregnancyCorpus LuteumNormal PregnancyProgesterone LevelEarly GestationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Intrauterine fetal sex determonation by radioimmunoassay of amniotic fluid testosterone.

Amniotic fluid testosterone levels were measured by a sensitive and specific radioimmunoassay technique from 75 term pregnancies and from 57 pregnancies prior to 20 weeks gestation. Statististically significant differences (p < 0.05) were found between levels for term males (123 pg/ml) and term females (63 pg/ml) and between less than 20-week males (176 pg/ml) versus less than 20-week females (60 pg/ml). However, the hormone levels between term males and less than 20-week males were not significantly different from each other, and, similarly, levels between term females and less than 20-week females were not statistically different. In this study, the sex of 37 out of 38 male fetuses and 19 out of 19 females less than 20 weeks gestation could be correctly predicted solely on the basis of amniotic fluid testosterone levels. The implications are apparent for genetic counseling by using this rapid methodology for intrauterine sex determination instead of, or in addition to, full chromosome analysis.

HEPATITIS-B ANTIGEN IN SALIVA AND SEMEN

Saliva and semen samples were obtained from twenty-four men whose serum was positive for hepatitis-B antigen (HBAg) and who had a variety of associated hepatitic conditions. Using a highly sensitive radioimmunoassay technique HBAg was detected in the saliva of eighteen of the twenty-four. In ten of these eighteen men the semen also contained HBAg. Detection of HBAg was checked by radioimmunoassay subtyping.