Radioimmunoassay Of Extracts Research Articles

A PHYSIOLOGICAL ROLE FOR CALCITONIN: PROTECTION OF THE MATERNAL SKELETON

Plasma-calcitonin levels, measured with an established and reliable extraction radioimmunoassay technique, were significantly higher throughout normal pregnancy and lactation than in normal non-pregnant women, and were not immediately influenced by the acute stimulation of breast-feeding. Thus, more calcitonin circulates at times of physiologically increased calcium need. It is suggested that an important function of calcitonin is the protection of the healthy maternal skeleton from excessive resorption by opposing the resorptive action of 1,25-dihydroxycholecalciferol on bone.

ProACTH: Use for early detection of lung cancer

ProACTH was identified by radioimmunoassay and column chromatography in extracts of 38 lung carcinomas. One hundred patients were evaluated because of abnormalities on chest roentgenograms; 53 (72 per cent) of 74 with lung cancers had increased plasma ACTH immunoreactivity; all 26 with benign abnormalities had normal ACTH. Of 101 patients with obstructive lung disease, five of 20 with elevated plasma ACTH levels and two of 81 with normal plasma ACTH levels had lung cancer within two years. In three of 31 patients with granulomatous lung disease plasma ACTH levels were elevated during acute exacerbation of the disease, but they returned to normal after recovery. We conclude that plasma ACTH immunoreactivity is frequently increased early in the course of lung carcinoma.

An Escherichia coli mutant defective in single-strand binding protein is defective in DNA replication.

An Escherichia coli mutant, temperature-sensitive for DNA synthesis in vivo and in vitro, is defective in single-strand binding protein (SSB; DNA-binding protein). Conversion of phage G4 single strands to the duplex form is defective in crude enzyme fractions of the mutant and is complemented by pure wild-type SSB. Radioimmunoassays of mutant extracts show normal levels of material crossreacting with anti-SSB antibody. SSB purified to homogeneity from the mutant is active, with lower specific activity, in the reconstituted G4 replication assay at 30 degrees C, but virtually inactive at 42 degrees C. Surprisingly, the mutant protein, like the wild-type protein, survives heating at 100 degrees C. Thus, mutant SSB is structurally heat-resistant but is functionally thermosensitive in vitro and in vivo. Both the in vivo and in vitro defects are tightly linked in transductions by phage P1. The mutation in the binding protein, designated ssb-1, is located between 90 and 91 min on the E. coli genetic map.

Bombesin-like immunoreactivity in the avian gut and its localisation to a distinct cell type

The distribution of a bombesin-like immunoreactive peptide in the avian gastro-intestinal tract was analysed by combined radioimmunoassay and immunocytochemistry. Radioimmunoassay of tissue extracts showed that the largest quantities of bombesin-like immunoreactivity were present in the proventriculus (64.5 +/- 6.0 pmol/g) with smaller but still considerable amounts in the gizzard (40.0 +/- 6.0 pmol/g). Immunocytochemically the extractable bombesin-like immunoreactivity was localised in numerous endocrine cells. These, in the proventriculus, were found mainly in the deeper layers of the mucosa. Further study of these cells by the semi-thin/thin technique revealed the presence of characteristic secretory granules. The functional name BN is proposed for this cell type.

An immunohistochemical and radioimmunological study of the distribution of [Met 5]- and [Leu 5]-enkephalin in the gastrointestinal tract

The identification of opiate-like substances in extracts of the gastrointestinal tract and nervous system of vertebrates suggests that the known endogenous opiate-like peptides [Met 5]- and [Leu 5]-enkephalin might have a role in neurotransmission. In this study the gastrointestinal tract of guinea-pigs, rats and hamsters was examined by the immunoperoxidase-bridge method using specific antisera raised against [Met 5]- and [Leu 5]-enkephalin. Immunostained nerve fibers were most numerous in Meissner's plexus of the duodenum and in the circular muscle layer of the stomach and rectum of the guinea-pig. Nerve fibers in the guinea-pig esophagus and cardia of the stomach stained with [Met 5]- but not with [Leu 5]-enkephalin antiserum. Staining was not observed in any epithelial cells. The regional distribution of these peptides was also examined by radioimmunoassay of extracts of the gut of guinea-pigs and rats. The highest concentrations of [Met 5]- and [Leu 5]-enkephalin were found in extracts of guinea-pig duodenum at a ratio of 11:1, respectively. These findings provide evidence for an enkephalinergic nervous system in the gastrointestinal tract.

Carcinoembryonic antigen and other tumor markers in tissue and serum or plasma of patients with primary mammary carcinoma

50 patients with primary breast cancer were studied to determine the CEA and HCG contents in their tumor cells before any treatment was initiated. Tumor cells were obtained by needle biopsy and each tumor cell population was stained by immunofluorescence. In 21 of the 50 patients, CEA containing cells were found in a frequency ranging from 5 to 80% of the tumor cell population. The results were confirmed by radioimmunoassay of tumor extracts. No apparent relation was seen to cytologic type or grade of differentiation. HCG was detected by IF in 4 tumors with an apocrine cytologic cell type. The level of CEA in plasma was determined before treatment and followed for 2-6 months in 72 patients. CEA was the only measured serum parameter that correlated initially with size and extent of the localized tumor. It was too low to be of use for monitoring primary disease, but should be of value in early detection of metastasis. Posttreatment a low or decreased plasma CEA was seen more often in patients who had had curative treatment than in those given palliative radiation. No raised serum HCG levels were found. Raised serum liver enzymes did not predict the extent of the primary tumor but may be an indication of distant spread. Tumor CEA content and CEA plasma concentration were correlated, although not very strongly. This means that CEA, although present in the tumor, is not always released in measurable amounts.

Calcitonin and Carcinoembryonic Antigen as Tumor Markers in Medullary Thyroid Carcinoma

DeLellis, Ronald A., Rule, Allyn H., Spiler, Ira, Nathanson, Larry, Tashjian, Armen H., Jr., and Wolfe, Hubert J.: Calcitonin and carcinoembryonic antigen as tumor markers in medullary thyroid carcinoma. Am J Clin Pathol 70: 587–594, 1978. Six patients with locally advanced and/or metastatic medullary thyroid carcinoma, of both familial and non-familial types, had markedly elevated serum concentrations of calcitonin and carcinoembryonic antigen (CEA). The highest serum CEA concentrations were found in those patients with the most extensive disease and correlated with the extent of serum calcitonin elevation. Immunocytochemical studies revealed positive staining for CEA and calcitonin in tumor cells, and these results were confirmed by correlative radioimmunoassays of tumor extracts for CEA. Patterns of calcitonin and CEA immunoreactivity in tissue sections were similar but not identical. While most tumor cells contained both CEA and calcitonin, some groups of tumor cells that were strongly stained for calcitonin did not stain for CEA. In contrast to the granular staining pattern for calcitonin, CEA immunoreactivity tended to be diffusely distributed throughout the cytoplasm or was concentrated at the plasma membranes. Normal and hyperplastic C cells, on the other hand, showed strong staining for calcitonin but did not contain immunoreactive CEA. It is concluded that CEA is a useful tumor marker in patients with locally advanced or metastatic medullary thyroid carcinoma and that CEA and calcitonin can be produced by the same neoplastic cell populations.

The Ontogenesis of Human Fetal Hormones. IV. Somatostatin, Luteinizing Hormone Releasing Factor, and Thyrotropin Releasing Factor in Hypothalamus and Cerebral Cortex of Human Fetuses 10-22 Weeks of Age

Somatostatin, LRF, and TRF were measured by radioimmunoassay in extracts of hypothalami obtained from human fetuses between 10 to 22 weeks gestation. Iodinated LRF and somatostatin eluted mainly after the iodide peak (Kd ∼ 2), free of the unlabeled factor when purified on Sephadex G25 with 0.1M acetic acid as eluant. Of 3 anti- LRF sera used, one did not recognize any of 21 LRF fragments but could detect analogs with changes in position 2 and 8; a second only recognized the 7–10 C-terminal sequence, and the third was directed against positions 5–9. Hypothalamic or brain extracts produced parallel displacement in each radioimmunoassay. Somatostatin was present in 43/44 fragments: mean content in 44 hypothalami was 14.9 ± 2.0 ng, concentration 16.8 ± 2.2 pg/mg; in 25/27 cerebral cortex tissues, 4.2 ±1.1 pg/mg. There was weakly positive correlation between hypothalamic somatostatin and gestational age in the 10 to 22 week period (r = 0.388, P < 0.01). The mean content of LRF in 33/44 hypothalami was 1.53 ± 0...

Biosynthesis of adrenocorticotropic hormone in mouse pituitary tumor cells.

A double antibody immunoprecipitation technique using affinity-purified adrenocorticotropic hormone (ACTH) antiserum was employed to investigate the biosynthesis of ACTH in a mouse pituitary tumor cell line. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of cell extracts resolved four forms of ACTH with apparent molecular weights of 4,500, 13,000, 23,000, and 31,000. These four forms of ACTH can be detected by radioimmunoassay of cell extracts or by immunoprecipitation of cell extracts following incubation of cultures in [3H] tryptophan, [3H] lysine, or [3H] tyrosine. The double antibody immunoprecipitation scheme developed is specific, quantitative, and reproducible. ACTH biosynthesis was examined in both steady and pulse-labeling experiments using [8H] tyrosine or [3H] lysine. The results of these experiments are consistent with the proposal that Mr=31,000 ACTH is the biosynthetic precursor for all three smaller forms of ACTH and that Mr=23,000 ACTH is a biosynthetic intermediate. Both Mr=13,000 ACTH and Mr=4,500 ACTH are derived from the intracellular processing of Mr=31,000 ACTH.

Histologic identification and immunochemical studies of prolactin and growth hormone in the primate pituitary gland

The two acidophilic cell types were tinctorially differentiated in rhesus monkey pituitaries as well as in pituitaries of other species of monkeys and apes and were identified by immunofluorescence as the prolactin and the growth hormone (GH) cells. The number of prolactin cells was significantly greater in adult than in juvenile rhesus monkeys. During late pregnancy and lactation, these cells appeared to occupy 60–80% of the entire anterior lobe of the rhesus monkey. The concentration of prolactin and CH was measured by radioimmunoassay in pituitary extracts (PE) from pools of juvenile male, juvenile female, adult male and adult female rhesus monkey pituitaries. More prolactin was present in PEs from adult than from juvenile animals, with the highest concentration being present in adult females. A similar relationship was observed with GH. The qualitative immunologic relationship between ovine prolactin and prolactin in the rhesus monkey PEs, and between human GH and GH in the PEs, was established using agar gel diffusion. The two prolactin hormones were partially related immunochemically, while the two GHs were shown to be immunochemically identical. In intact juvenile female rhesus monkeys given estradiol benzoate, the concentrations of pituitary and serum prolactin were elevated over that of the controls, while the concentration of pituitary GH was decreased. An increase in the number of prolactin cells was also observed in the steroid-treated animals. These observations demonstrate further that prolactin and GH reside in separate cells in the primate pituitary and that the concentration of these two hormones varies depending upon age, sex, or stage of the reproductive cycle of the animal.

24-Hour urinary luteinizing hormone (LW) and follicle stimulating hormone (FSH) excretion in normal children.

ABSTRACT Luteinizing hormone (LH) and follicle stimulating hormone (FSH) were measured by radioimmunoassays (RIA) in extracts of 153 24-hr urine specimens from 42 normal children ages 5–10. The results were compared with previously reported measurements on the same specimens by the mouse uterine weight assay (1). LH and FSH could be measured in nearly every sample. A bimodal pattern of LH excretion was found in most of the children studied. LH excretion was characterized by relatively constant daily urinary excretion levels punctuated by intermittent bursts of increased excretion occurring approximately 1 out of 6 days. FSH excretion was similar, but FSH peaks were not as prominent and were not always coincident with LH peaks. The RIA measurements in those specimens which had been negative on the bioassay showed small increases in urinary LH and FSH excretion during childhood. The increase for LH was gradual; FSH excretion doubled between ages 5–6 and 7–8. No significant differences in the excretion of LH...

Post-partum release of luteinizing hormone (LH) in the rat as determined by radioimmunoassay.

To determine the time, extent and duration of the release of luteinizing hormone (LH), concentrations of LH were determined by radioimmunoassay in extracts of anterior pituitary glands and in sera drawn several times during the day from pregnant and post-partum rats. In the pregnant rat, no peaks in concentrations of LH in serum were found in 85 samples collected. Elevated concentrations of LH were seen as early as 2 hr after delivery, with the greatest percentage occurring between 7 and 10 hr after delivery. These elevated concentrations occurred as early as 7 AM on the day of delivery and as late as 3 in the morning of the day following delivery. Sequential samples from individual rats showed that the onset of the rise in serum LH occurred between 3 and 11 hr after delivery. The release of LH was rapid, with at least a 15-fold rise in concentration (and perhaps as much as a 60-fold increase) occurring in as little as 2 hr in some cases. The initial fall in serum LH concentrations was likewise rapid. The...

Immunochemical heterogeneity of parathyroid hormone in plasma.

ABSTRACT Immunoreactive parathyroid hormone was measured by radioimmunoassay in extracts of parathyroid glands and tumors and in plasmas from patients with 1°, 2° or 3° hyperparathyroidism. On serial dilution most extracts showed approximately parallel behavior in 2 or 3 different antisera. However, plasma specimens referred to the same extract as standard frequently showed greater immunoreactivity in 2 antisera (272 and 273) than in a third antiserum (C329). This anomaly was more marked in plasma from patients with hyperparathyroidism secondary to renal insufficiency than in plasma from patients with 1° hyperparathyroidism and was exhibited by some extracts of adenomas as well. Following parathyroidectomy, the apparent disappearance of parathyroid hormone was more rapid when measured in antiserum C329 than in antiserum 273 and in both antisera was slower in patients with renal insufficiency than in patients with 1° hyperparathyroidism. These findings suggest that parathyroid hormone in human plasma is im...

Distribution of immunoassayable glucagon in gastrointestinal tissues

Glucagon has been identified by a specific radioimmunoassay in extracts of canine stomach and duodenum, rat stomach, duodenum, and jejunum, and human jejunum. Canine stomach glucagon appears to be similar to glucagon of pancreatic origin with respect to its immunoreactivity, its gel filtration elution pattern, and its in vivo hyperglycemic activity. The implication of these findings are briefly discussed.