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Biomedical subjects

R E Priest

Publications and source records attributed to R E Priest.

At least 19 recordsLinked to original sources
PubMed1988

The phytohemagglutinin response of human peripheral blood lymphocytes as a function of donor age: a re-examination using BrdU-Hoechst flow cytometry.

Mononuclear cells were isolated from peripheral blood by a standard Ficoll-Hypaque technique from 127 healthy donors, ranging in age from newborns to 86 years of age. As a measure of their in vitro growth response, the fraction of non-cycling cells was determined at 48 and 72 h after phytohemagglutinin (PHA) exposure by means of BrdU-Hoechst flow cytometry. This technique provides an optimal assay system for the non-cycling cell fraction, since all cycling cells will have incorporated BrdU thereby quenching the fluorescence of the Hoechst 33258 fluorochrome. Lymphocytes from prepubertal donors showed significantly decreased non-cycling cell fractions, as did lymphocytes from an additional group of 14 adults with hypogonadism due to the 45, XO condition (Turner-Syndrome). Much to our surprise, we found no definitive correlation between donor age and the non-cycling fraction of cells from the adult lymphocyte donors. Nor did we find any age-related increase in the variance of the non-cycling cell fraction. These observations suggest that the previously reported age-related decline in the PHA response of human PBL may reflect an increasing delay, rather than an overall diminution, of the PHA response as a function of donor age.

Adolescent↗
PubMed1985

Oxygen dependence of oestrogen production by human placental microsomes and cultured choriocarcinoma cells.

The oxygen dependence of oestrogen (oestrone and 17 beta-oestradiol) formation from androstenedione and testosterone was studied in term human placental microsomes and in cultured human choriocarcinoma cells (BeWo line). Incubations were performed under various steady-state oxygen concentrations and the production of oestrone and 17 beta-oestradiol quantitated by specific radioimmunoassays. The aromatization of C19-steroids by both placental microsomes and choriocarcinoma cells was shown to be oxygen dependent over a wide range of O2 concentrations. The results indicate that placental oxygenation may be a critical factor in determining oestrogen production in vivo. Therefore, impaired oestrogen biosynthesis due to hypoxia could be an important factor in a variety of physiological and pathological conditions.

Androstenedione↗
PubMed1985

Characterization of two types of crystalloids in pleomorphic adenomas of minor salivary glands. A light-microscopic, electron-microscopic, and histochemical study.

Crystalloids have been previously described in salivary gland tumors. In order to ascertain the incidence of these structures, the authors reviewed a series of 294 minor salivary gland tumors. One hundred thirty pleomorphic adenomas were identified, and 6 of these contained crystalloids. No crystalloids were found in other benign or malignant salivary gland tumors. These six file cases and a recent seventh case containing crystalloids were studied by light and electron microscopy and with histochemistry. Two types of crystalloids were found. One case contained previously described tyrosine-rich crystalloids, and the other six contained crystalloids composed of radially arranged collagen fibers. Both types of crystalloids are further characterized and discussed.

Adenoma, Pleomorphic↗
PubMed1984

Metabolism of [4-14C]androstenedione by cells cultured from human amniotic fluid.

The conversion of [14C]androstenedione by human fibroblast (F) and amniotic fluid (AF) cells obtained by amniocentesis was investigated using human dermal fibroblasts (DF) as controls. Cell suspensions were incubated with [14C]androstenedione in the presence of a NADPH generating system. Steroid reaction products were separated from unreacted substrate by chromatography on micro-columns of magnesium oxide, partially resolved by partition chromatography on celite and further characterized by thin-layer chromatography and recrystallization to constant specific activity. In the case of F cells the pattern of metabolism was qualitatively similar to that of DF cells; the predominant metabolite was testosterone and several uncharacterized metabolites were detectable. However testosterone was the only metabolite isolated from incubations with AF cells. The results demonstrate distinct differences in the capacity of AF and F type cells to metabolize [14C]androstenedione and support the view that F cells resemble typical fibroblasts from dermis or other connective tissues.

Amniotic Fluid↗
PubMed1983

Characterization of hCG regulation in cultured human amniotic fluid cells: II. Mechanisms for stimulation.

We showed previously that sodium butyrate stimulated human chorionic gonadotropin (hCG) measured by radioimmunoassay of medium from human second trimester amniotic fluid cell cultures, termed AF cells. We now find that stimulation of hCG in the presence of sodium butyrate takes as long as 20 h. When AF cells are preincubated with sodium butyrate, hCG levels increase in direct relation to length of the preincubation period. These findings suggest that elevation of hCG is not due merely to a release of hormone from the cells. Addition of cycloheximide or Actinomycin D inhibited protein synthesis and RNA synthesis, respectively, and prevented the stimulation of hCG by sodium butyrate. These results lend support for a mechanism of regulation involving protein and RNA synthesis, the increase in hCG levels being due to new synthesis of the hormone. Other agents reported to influence hCG production by different types of cell cultures include dibutyryl cyclic AMP, epidermal growth factor (EGF), methotrexate, and hydroxyurea. Dibutyryl cyclic AMP and EGF have no effect on hCG production in our AF cells: methotrexate causes a minimal increase, hydroxyurea causes a further increase, but sodium butyrate has the strongest stimulatory effect. We conclude that amniotic fluid cells in culture are susceptible to environmental agents capable of modulating synthesis of hCG by mechanisms involving synthesis of RNA and protein.

Amniotic Fluid↗
PubMed1983

HLA typing of cultured amniotic fluid cells.

HLA typing was performed on 18 cultures of human amniotic fluid cells using cytotoxicity and absorption technics. Confirmation of antigen assignments was obtained in nine of ten instances, where HLA typing also was performed on cord blood. Three major problems were encountered in performing these studies: (1) complement cytotoxicity, (2) false-positive reactions, and (3) false-negative reactions. False-positive and false-negative reactions occurred more frequently with sera defining HLA-B locus specificities than with sera defining HLA-A locus specificities. Absorption studies were helpful in making antigen assignments when false reactions occurred. Preliminary studies suggest that the frequency of false-positive reactions can be decreased by absorbing HLA typing sera with antigen-negative amniotic fluid cultured cells, buffy coat, or platelets. Accurate antigen assignment is difficult when parental HLA types are unavailable.

Absorption↗
PubMed1981

Endurance training in the rat. I. Myocardial mechanics and biochemistry.

The effects of physical training and detraining on cardiac structure and myocardial mechanics were studied in young and adult male rats trained by graded treadmill running for 12 wk and compared with sedentary controls. Detraining was produced by training for 12 wk followed by 6 sedentary wk. A training effect was demonstrated by increased succinate dehydrogenase activity in skeletal muscle (trained 10.0 +/- 1.2 mumol . g-1 . min-1; sedentary 6.4 +/- 0.8 mumol . g-1 . min-1; P less than 0.05). Although heart weight-to-body weight ratios were increased in trained rats of both ages, left ventricular fiber diameters and myocardial RNA, DNA, and collagen content were unchanged by training. Active and passive mechanics (myocardial contractility and stiffness) were studied in left ventricular papillary muscles and did not differ significantly between groups, with the exception of depressed contractility observed in young trained rats [(e.g., papillary peak developed isometric tension at Lmax (length at peak tension)] was 2.64 +/- 0.24 g/mm2 in trained vs. 3.59 +/- 0.22 g/mm2 in sedentary (P less than 0.01). This difference was abolished by detraining. Papillary muscle contractile responses to calcium, norepinephrine, and hypoxia were not altered by training or detraining. In conclusion, moderate endurance training did not result in significant cardiac hypertrophy, altered myocardial stiffness, or consistent changes in myocardial contractility.

Animals↗
PubMed1979

Isolation and characterization of hydroxyproline-containing proteins secreted by a murine carcinoma cell culture.

A collagenous protein was isolated from a murine carcinoma cell culture, which has been shown to synthesize basement membrane. The molecular weight of this protein was estimated to be 155 000. It eluted from carboxymethyl-cellulose in the region near the alpha 1 and beta 11 components of calf skin collagen. 63--69% of the peptide-bound prolines were hydroxylated, and the 4-/3-hydroxyproline ratios ranged from 12 : 1 to 14 : 1. About 95% of the hydroxylysines in the peptide were glycosylated, and almost all of them were in the glucosylgalactosyl dissacharide form. Judging from the posttranslational characteristics, this collagenous protein is probably of basement membrane type.

Animals↗
PubMed1979

Differentiation in human amniotic fluid cell cultures: chorionic gonadotropin production.

Two of the distinguishable cell classes subcultured from human amniotic fluid were examined for their capability to produce human chorionic gonadotropin (hCG) as determined by radioimmunoassay. The class that predominates in most cultures used for prenatal genetic diagnosis, previously termed AF (for amniotic fluid), secretes hCG into the culture medium. Dermal fibroblasts do not, nor does another type of cultured cell from amniotic fluid, previously termed F because of a resemblance to fibroblasts. Primary AF cultures produce more hCG than do subcultures. Evidence that this hormone is intact hCG is provided by its immunoreactivity with antisera raised against the beta-subunit and against the intact molecule of hCG. Furthermore, a dose-response curve for hormone in culture medium is parallel to that of highly purified intact hCG. It is postulated that AF cultures are derived from fetal membranes and retain properties of trophoblast.

Amniotic Fluid↗
PubMed1978

Origin of cells in human amniotic fluid cultures: ultrastructural features.

Two classes of cells can be subcultured from human amniotic fluid (F and AF). Ultrastructural features of these cultrued cells were determined using scanning and transmission electron microscopy with particular attention to extracellular material. Results obtained from these two cell types are compared to one another and to cultured human dermal fïbroblasts. The F-type cultures have an abundance of extracellular type i collagen fïbers, identical with cultured human dermal fïbroblasts. No type I collagen fïbers are seen in cultures of AF cells. Instead, fïne fïlamentous material is admixed with amorphous material adjacent to cell membranes where epithelial basement membrane glycoprotein has been localized. By scanning electron microscopy parallel arrays of cells are present at confluency of F cultures, typical of cultured dermal fïbroblasts. AF cultures show a much looser growth pattern at confluency. On the basis of accumulated evidence, we believe that F-type cells arise from fïbrous connective tissue and are fïbroblasts, whereas AF cells, the predominant type in early cultures used for prenatal genetic diagnosis, arise from fetal membranes and retain features of trophoblast.

Amniotic Fluid↗
PubMed1977

Differentiation in human amniotic fluid cell cultures: I: Collagen production.

The collagen produced by differentiated cells cultured from human amniotic fluid was characterized in two ways. By chain composition and by 4-hydroxyproline:3-hydroxyproline isomer ratio, the collagen synthesized by F-type (fibroblast) cells was indistinguishable from that made by cultured fetal dermal fibroblasts. The predominant cells in young amniotic fluid cultures, termed AF-type, produced collagen with a lower isomer ratio, resembling that of basement membrane collage. The chain composition, as determined by chromatography on carboxymethyl cellulose, varied for different cultures of the AF-type, but the major pattern was consistent with that of basement membrane collagen. On the basis of these characteristics, F cells are of fibroblast origin, whereas most AF cells are of a different origin either endothelial or epithelial. Other evidence (Megaw et al., 1977) suggests an epithelial origin for AF cells.

Amniotic Fluid↗
PubMed1977

Differentiation in human amniotic fluid cell cultures: II: Secretion of an epithelial basement membrane glycoprotein.

Cells obtained by amniocentesis for prenatal diagnosis were grown in vitro and examined for the presence of a glycoprotein component epithelial basement membrane. Isolated colonies or clones of amniotic fluid-type cells secrete the glycoprotein, which was identified in association with the cells using indirect immunofluorescent antibody techniques. In addition, the glycoprotein was isolated from tissue culture medium and identified as a component of epithelial basement membranes by passive haemagglutination (PHA) and immunodiffusion assays. Fibroblast-type cells do not secrete the glycoprotein. These results correlate well with the synthesis of type IV collagen by amniotic fluid cells reported in the accompanying paper (Priest et al., 1977) and indicate that amniotic fluid cells are epithelial in origin.

Amniotic Fluid↗