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Biomedical subjects

A Castro

Publications and source records attributed to A Castro.

At least 487 records · Page 27Linked to original sources
PubMed1980

Tissue immunoreactive prolactin hormone in breast cancer.

The prolactin contents of the cytosol extracts of 159 human mammary carcinomas was measured by specific radioimmunoassay. Of these extracts 157 contained measurable prolactin (detection limit, 7.8 ng/g tumor). The levels measured were in most cases greater than would be expected to be due to only serum contamination. The levels of prolactin did not correlate with either estrogen or progesterone receptor content of the tumors, or menopausal status of the patient.

Breast Neoplasms↗
PubMed1980

Immunochemical demonstration of immunoreactive insulin in human breast cancer.

The immunoreactive insulin contents of the cytosol extracts of 57 human mammary carcinomas were measured by specific radioimmunoassay. All of these extracts contained measurable insulin (detection limit 1.3 ng/g tumor). In some cases (23) the levels were quite greater than the normal human serum levels. Immunoperoxidase technique revealed the presence of immunoreactive insulin within the cytoplasm of tumor cells in 6 cases.

Adult↗
PubMed1980

Modifying cerebral candidiasis by altering the infectious entry route.

Diffuse leptomeningitis did not occur in healthy adult male Wistar rats with transient candidemia produced by the injection of organisms into the internal carotid artery, even though intraparenchymal microabscesses with yeasts and pseudohyphae were seen throughout the brain. Candida albicans was culturally identified in the brain and kidney. Injecting the organisms into the cisterna magna caused an infection characterized by lymphocytes and histiocytes and was confined to the leptomeninges. In this meningeal model, fungi were recovered only from the CNS. The overwhelming prevalence at autopsy of cerebral candidal microabscesses without diffuse leptomeningitis is apparently due to transient candidemia. Meningitis due to candidemia is rare and seems to require a microabscess that is accessible to the circulating CSF. This latter event is a late and overwhelming feature of cerebral candidiasis.

Animals↗
PubMed1980

Phenobarbital specific antibody production: preparation of 5-phenyl-5-(4-aminobutyl) barbituric acid-bovine serum albumin conjugate.

The aminobutyl derivative of phenobarbital, 5-phenyl-5-(4-aminobutyl)barbituric acid hydrochloride, was synthesized through two synthetic pathways for the preparation of immunogen in production of phenobarbital specific antibody. The produced antiserum had high titer, specificity, affinity and sensitivity (0.5ng/ml), when examined by radioimmunoassay.

Animals↗
PubMed1979

Ectopic human chorionic gonadotropin in breast carcinoma.

Immunoreactive human chorionic gonadotropin (hCG) was found in 9 of 65 surgically removed malignant breast tumors. Concentrations ranged from 5 to greater than 500 mIU hCG/g tumor. hCG was measured by a beta-chain specific readiommunoassay. In further study of these specimens, an immunoperoxidase staining technique was used to stain for hCG in formalin-fixed sections. The hCG was shown to be localized within the cytoplasm and on the surface of the malignant cells.

Breast Neoplasms↗
PubMed1979

Automated radioimmunoassay of nicotine.

We have developed an automated nonequilibrium procedure for the radioimmunoassay of nicotine. The use of a unique iodinated nicotine derivative in this procedure gave a sensitivity of 10 micrograms/l for nicotine with a between-run precision of 7.4% and within-run precision of 6.0%. Nicotine levels of 60 to 67 micrograms/ml were found in subjects 15 min after smoking one standard cigarette. The technique herein reported is a very rapid, and sensitive radioimmunoassay for nicotine and facilitates the determination of nicotine in smoking subjects during the actual process of smoking.

Adult↗
PubMed1979

Immunoglobulin G- and M-specific enzyme-linked immunosorbent assay for detection of dengue antibodies.

An enzyme-linked immunosorbent assay for the detection of antibodies to dengue virus is described. This method correlates well with a hemagglutination inhibition technique. The enzyme-linked immunosorbent assay can also be specific for human immunoglobulin M antibodies when a mu-chain-specific antiglobulin-enzyme conjugate and fractionated serum are employed. By using this technique, dengue immunoglobulin M antibodies were demonstrated in an infant suspected of having a recent dengue infection.

Antibodies, Viral↗
PubMed1979

Enzyme-linked immunosorbent choriomammotropin assay.

We have devloped an enzyme-linked immunosorbent assay for determining choriomammotropin (human placental lactogen) in serum. Unlabeled hormone competes with choriomammotropin-beta-galactosidase conjugate for antibody bound to polystyrene tubes. The entire assay can be performed in 2.5 h with good precision. The coefficient of variation for one sample with a mean concentration of 5.6 mg/L, assayed 10 times on the same day, was 5.7%. The coefficient of variation for nine samples (3.5 to 9.0 mg/L) assayed on five different days was 7.9%. Forty-eight clinical samples were assayed (y) and compared with results obtained by radial immunodiffusion (x). The resulting regression equation was: y = 1.05x + 0.78; r = 0.91.

Enzyme-Linked Immunosorbent Assay↗
PubMed1979

Steric hindrance enzyme immunoassay (SHEIA); a novel method in enzyme immunoassay.

We have developed a new method for separation of antibody bound and unbound enzyme conjugates. The technique as applied to the assay of choriomammotropin involves the use of beta-D-galactosylamine bound to agarose to separate the unbound choriomammotropin-beta-galactosidase conjugates for antibody bound conjugates. When beta-galactosidase was conjugated with choriomammotropin using the N-hydroxy-succinamide ester of m-maleimidobenzoic acid the affinity of the enzyme conjugate to beta-D-galactosylamine attached to agarose diminished markedly following incubation with antibody. In a typical enzyme immunoassay of choriomammotropin, 5 microliter of swelled affinity gel per tube was required to precipitate unbound enzyme following one hour gentle shaking at room temperature. Choriomammotropin antibody was used at titer of 1:1,000. The standard curve for the assay was adjusted to cover a range of 0-10 mg/l with maximum sensitivity between 1-4 mg/l.

Animals↗
PubMed1979

A new radioassay for serum vitamin B12 determination using chicken serum as a binder and an anion exchange resin column separation.

We present a new method for the determination of serum vitamin B12 concentration by competitive protein binding using 57Co labeled vitamin B12, chicken serum (CS) as the binding protein, and a sephadex column separation. We placed a mixture of extracted sample, labeled B12, and CS binder above an A-25 sephadex column, and after 1 hour incubation at room temperature drained the column and washed it twice with buffer. We counted the free fraction remaining in each column. Within run C.V.'s for low and high values in the normal range were 10.6% and 6.03%. The between run C.V.'s were 7.7% and 7.5% respectively. The values obtained for 95 clinical specimens correlated well with those for a reference method.

Animals↗
PubMed1979

Plasma nicotine pharmacokinetics in dogs after intravenous administration: determination by radioimmunoassay.

Nicotine plasma levels in dogs were examined by radioimmunoassay after intravenous administration of S-nicotine at the dosage of 100 microgram/kg. After a rapid decline of nicotine level in plasma immediately following the injection, retention of the level was observed until 30 min. From that point the plasma level decreased monoexponentially. A biological half life (t 1/2, beta) of 0.61 hr we observed in dogs was similar to that in man and one half of that in rats. Total body clearance (TBC) and apparent volume of distribution (Vd, beta) in dogs were about 1/5 of that in rats. The results suggested that nicotine does not distribute in dogs as readily as in rats. Similarity in a biological half life of nicotine in dogs and humans suggested that the dog may be a better experimental model than the rate in the investigation of pharmacokinetic parameters for nicotine.

Animals↗