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Biomedical subjects

J Rasor

Publications and source records attributed to J Rasor.

15 recordsLinked to original sources
PubMed1985

A new method for assessing right-sided heart pressures using encapsulated microbubbles--a preliminary report.

A new noncatheter method for measuring pressures of the right side of the heart uses specially manufactured microbubbles of carbon dioxide injected into the peripheral venous system. Sudden expansion of these bubbles in the cardiac chambers causes bubble oscillations at a frequency that is primarily a function of surrounding pressure. The oscillations are recordable by a microphone on the chest wall. The preliminary experience has been in dogs and further development is needed before we can begin clinical testing of the method. In its current form, the potential for measuring higher systolic pressures seems better than that for lower diastolic pressures.

Animals↗
PubMed1984

Varying bioactive to immunoactive ratios of the human chorionic gonadotropin-like substance present in normal human tissues.

To further characterize the hCG-like substance found in normal nonpregnant human tissues, we compared the biological (B) and immunological (I) activities of the substance in extracts of 40 nontrophoblastic tissues and 7 placentas. B was measured in an in vitro mouse testicular interstitial cell bioassay, and I was measured in the beta hCG RIA. Highly purified hCG (CR 119) was used as a standard. B was detected in 92% of the nontrophoblastic nonpituitary tissues. Parallelism between serial dilutions of extracts and the hCG standard was found for 75% of the pituitary extracts, 86% of the placental extracts, and 53% of the other tissues. The correlation between B and I activities in the nontrophoblastic nonpituitary tissues was good (r = 0.8; P less than 0.001). Preincubation of the tissue extracts with anti-hCG serum before bioassay significantly reduced the B activity. There was wide variation in the B to I ratio between tissues and within the same tissues from different individuals. A B to I ratio less than 1 was found in 50% of the tissues, excluding placenta and pituitary, and may have been due to the presence of incomplete or altered hCG molecules, which are immunologically active but have reduced B activity.

Animals↗
PubMed1980

Maternal serum human chorionic gonadotropin concentrations and fetal sex prediction.

The feasibility of using maternal serum human chorionic gonadotropin (hCG) concentrations for prenatal sex prediction was examined. hCG was mesured in 822 serum samples from 560 women with uncomplicated pregnancies. Significantly higher hCG concentrations were found in the serum of women bearing female fetuses than in the serum of women bearing male fetuses during the third trimester, especially during the 10th lunar month. The data were utilized to construct probability graphs for fetal sex prediction based upon a single maternal serum hCG determination during the third trimester and during the 10th lunar month. However, the utility of these graphs is limited by the small proportion of pregnant women with serum hCG concentrations that were high or low enough to allow a prediction with high probability.

Chorionic Gonadotropin↗
PubMed1979

Widespread distribution of a chorionic gonadotropin-like substance in normal human tissues.

Recent studies have demonstrated that the normal human testes, colon, and liver contain a substance that resembles hCG. To extend these findings, we examined aqueous extracts of a variety of normal human tissues for the presence of this material. The beta-hCG RIA, rat Leydig cell radioreceptor assay, and a newly developed, highly specific hCG RIA were used to measure hCG activity in a serial dilutions of the extracts. Detectable concentrations of the hCG-like material were found in 146 of the 149 individual tissue samples studied. Parallelism was noted between the hCG standard and serial dilutions of extracts of testis, ovary, pituitary, lung, liver, kidney, spleen, stomach, placenta, and some small intestinal tissue samples in the beta-hCG RIA, radioreceptor assay, and the highly specific hCG RIA. An absence of parallelism was found between extracts of nonpituitary tissues and LH in the beta-LH RIA. Pancreatic extracts altered the [125I]hCG used as the labeled ligand in these assays, which led to spurious results. Chromatography of the extracts on Concanavalin A-Sepharose columns revealed that the hCG-like materials from different tissues varied widely in their adsorbtion to Concanavalin A, possibly reflecting differences in their carbohydrate contents. These results indicate that an hCG-like substance is widely distributed throughout normal human tissues and further supports the concept that the fetal genome responsible for hCG production is not completely suppressed in adult tissues.

Aging↗
PubMed1978

Properties of human chorionic gonadotropin produced in vitro by ovarian carcinoma cells.

The present study was designed to compare the immunological, physical, and biological properties of native hCG with an hCG molecule secreted ectopically in vitro by an ovarian adenocarcinoma cell line maintained in long term tissue culture. The hCG produced by the cell line was concentrated by ultrafiltration of the tissue culture medium. The inhibition curves generated by serial dilutions of the culture medium concentrates were parallel to those obtained with purified urinary hCG in the beta-hCG RIA and the rat Leydig cell radioreceptor assay (RRA). The ectopic hCG also reacted with an antibody generated against the carboxyl-terminal peptide (109-145) of beta-hCG. The immunoreactive material cochromatographed with urinary hCG on a Sephadex G-100 column, as determined by the beta-hCG RIA and RRA. Neither free alpha nor free beta subunits were found in the tissue culture medium. The tissue culture gonadotropin was adsorbed onto a Concanavalin A-Sepharose column and could be eluted with alpha-D-methylglucoside. The biological activity of the ectopic hCG was 9289 IU/mg, as determined by the ventral prostate weight (VPW) method in hypophysectomized immature male rats. The biological to immunological ratios by the ventral prostate weight method and RRA were 1.79 and 2.17, respectively. The in vivo disappearance rate of ectopic hCG after injection into immature female rats was significantly faster than that of placental or urinary hCG, but was considerably slower than the disappearance rate of human LH. These studies demonstrate that the immunoreactive and biologically active portions of the hCG produced by the ovarian adenocarcinoma cell line and native hCG are similar or identical. The faster disappearance rate of the ectopic hCG in the rat model may be due to incomplete sialylation of the oligosaccharide moiety of the hCG molecule.

Animals↗
PubMed1976

Serum human chorionic gonadotropin levels throughout normal pregnancy.

Human chorionic gonadotropin (hCG) levels were measured in the sera of 443 pregnant women by the beta-hCG radioimmunoassay in order to determine if the third-trimester secondary peak in hCG levels observed by less specific immunoassays was due to cross-reacting substances. hCG was detected as early as six days after presumed conception and peaked between 56 and 68 days, with a nadir at 18 weeks. No secondary rise in hCG levels was demonstrated, indicating that the nonspecific hCG immunoassays give spuriously high values for hCG during the last trimester of pregnancy.

Chorionic Gonadotropin↗
PubMed1975

Presence in normal human testes of a chorionic-gonadotropin-like substance distinct from human luteinizing hormone.

The high rate of human chorionic gonadotropin production by testicular tumors caused us to investigate the possibility that normal human testes contain small amounts of that substance. Extracts of human testes obtained at autopsy demonstrated parallel inhibition curves to the human chorionic gonadotropin standard in a radioimmunoassay specific for the hormone. The immunoreactive material was adsorbed onto concanavalin A, a reaction characteristic of glycoproteins, and was eluted within the chorionic gonadotropin range on Sephadex G-100 column chromatography. Solubilized receptor proteins for the hormone could not be identified in the extracts. The demonstration that the normal human testes contain a glycoprotein similar or identical to human chorionic gonadotropin suggests that the fetal genome responsible for production of the hormone during pregnancy is not completely suppressed in the adult. Excessive productton of this glycoprotein may account for the high levels of human chorionic gonadotropin reported in the serum of patients with germ-cell tumors of the testes.

Adult↗
PubMed1975

A simple radioimmunoassay for unconjugated estriol in pregnancy plasma.

A simple and specific radioimmunoassay (RIA) for the measurement of plasma or serum unconjugated estriol (E3) in pregnancy is described for general laboratory use. Two different antibodies utilized had low cross-reaction to estrone (E1) and estradiol-17 beta (E2). With either of these antibody reagents, a method was designed that requires only an extraction step using a specific solvent mixture of ethyl acetate and n-hexane (3:2, v/v), one-hour incubation with working antibody, and separation of bound from free E3 by ammonium sulfate. Standard curves useful in the range of 0 to 2,000 pg. were obtained. This assay, requiring only 0.05 ml. of plasma, can be completed within 4 hours. The sensitivity of this RIA was 10 pg. The intra- and interassay coefficients of variation (CV) were 5.0 and 9.4 per cent, respectively. When E3 determinations by this method are compared with RIA values by a more complicated technique using Celite column chromatography, the results are not significantly different. There was a good correlation between our RIA and a standard urine E3 determination (n = 137, r = 0.82, p less than 0.001). Using our simplified method, the mean plasma E3 during pregnancy were 1.0 +/- 0.6 ng. per milliliter at 10 weeks, 2.3 +/- 0.6 ng. per milliliter at 20 weeks, 6.5 +/- 1.4 ng. per milliliter at 30 weeks, and 16.5 +/- 5.1 ng. per milliliter at term. Since the serum RIA reflects changes in free E3 which has a shorter half-life than conjugated E3, this rapid and simple method is attractive as an approach to monitor fetal-placental function.

Estriol↗
PubMedDate not supplied

Experimental brain abscess: enhanced sonography and pathologic correlation.

A new sonographic contrast agent, gelatin-encapsulated nitrogen microbubbles, was introduced intraarterially to enhance the high-resolution sonographic scan of an experimental brain abscess. The echogenicity produced by the microbubbles correlated closely to the site and distribution of abscess neovascularity. The contrast agent aided in the detection of small necrotic centers in the late stages of abscess evolution when these centers were not visualized on noncontrast sonograms. The echogenic effect of the microbubbles was maximum immediately after injection; it decreased by 5 min and had virtually disappeared at 15 min.

Animals↗