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Biomedical subjects

M E Harper

Publications and source records attributed to M E Harper.

At least 109 records · Page 6Linked to original sources
PubMed1982

Amplified dihydrofolate reductase genes are located in chromosome regions containing DNA that replicates during the first half of S-phase.

To obtain a better understanding of the relationship between metaphase chromosome banding patterns and genome organization, attention was focused on regions of metaphase chromosomes that were found to contain the genes for a specific cellular enzyme, dihydrofolate reductase (DHFR). These studies involved the use of highly methotrexate-resistant mouse lymphoblastoid cells (L5178YR), which contain approximately 300 times the number of DHFR genes present in parental cells (L5178YS). Karyotypic analysis revealed the presence of two very large, nonhomologous, marker chromosomes that were absent in the parental line. In situ hybridization of 3H-labeled cloned DHFR cDNA to metaphase chromosomes of L5178YR cells was used to localize the DHFR genes to a very large Giemsa (G)-negative region on each of the two large marker chromosomes. Regional patterns of DNA replication in metaphase chromosomes were studied by autoradiographic visualization of [3H]thymidine incorporation and by fluorescent microscopic visualization of bromodeoxyuridine incorporation. Because the amplified DHFR genes were present within two prominent cytogenetic regions on two easily identifiable chromosomes, it was possible to observe the following. The amplified DHFR genes were located in chromosome regions that replicated at the same time during the first half of a 9-h-S-phase. DNA replication began simultaneously and terminated simultaneously at many locations throughout each amplified region. We conclude that transcriptionally active DHFR genes are located within large G-negative regions of metaphase chromosomes and that the DNA within these regions replicates during the first half of S-phase.

Animals↗
PubMed1982

Chromosomal localization of the human placental lactogen-growth hormone gene cluster to 17q22-24.

Recombinant plasmid HCS-pBR322 containing a 550-base-pair (bp) insert of cDNA to human placental lactogen (hPL) mRNA was 3H-labeled by nick translation and hybridized in situ to human chromosome preparations in the presence of 10% dextran sulfate. A high percentage of cells (80%) were found to exhibit label on the distal end of the long arm of chromosome 17. Silver grains on this region constituted 25.5% of all labeled sites, allowing assignment of the hPL and growth hormone (hGH) genes, which have over 90% nucleotide homology in their coding sequences, to 17q22-24. A gene copy number experiment showed that both genes are present in approximately three copies per haploid genome.

Chromosome Banding↗
PubMed1981

The immunocytochemical detection of protein hormones in human prostatic tissues.

The immunocytochemical detection of four pituitary protein hormones in tissue from 13 patients with benign prostatic hyperplasia has been described. There have been marked differences in the distribution and intensity of reaction product attributable to the various hormonal antisera. The intracellular presence of endogenous prolactin and FSH in the epithelial cytoplasm has been suggested together with the stromal localization of growth hormone and prolactin. Minimal diffuse staining over most cellular components was observed with the LH antiserum. This technique has provided an invaluable means of studying the potential involvement of pituitary protein hormones in the control of prostatic function and disease.

Cytoplasm↗
PubMed1981

Localization of single copy DNA sequences of G-banded human chromosomes by in situ hybridization.

Recombinant lambda bacteriophage clone H3 containing a human DNA segment of 14.9 kb present in one or two copies per haploid genome was isolated. In situ hybridization in human metaphase chromosomes of the 3H-labeled cloned DNA resulted in highly significant labeling (53% of cells) of band p36 of chromosome 1, such that 22% of all chromosomal grains were located on this region. Hybridization was dependent upon the presence of dextran sulfate in the hybridization mixture and was not affected by repetitive DNA competitor. These results demonstrate localization of a single copy sequence on human metaphase chromosomes.

Azure Stains↗
PubMed1981

Localization of the human insulin gene to the distal end of the short arm of chromosome 11.

The human insulin gene was mapped by hybridization in situ of 3H-labeled recombinant plasmid pHIG900 to chromosome preparations in the presence of 10% dextran sulfate. pHIG900 contains a 900-base pair insert of human genomic DNA that includes the coding region for the C peptide and intervening sequence 2. A significant percentage of hybridized cells (34%) exhibited silver grains on the distal end of the short arm (band p15) of chromosome 11. Furthermore, silver grains on this region represented 26% of all chromosomal label. These results demonstrate chromosomal localization of the human insulin gene to 11p15.

Chromosome Mapping↗
PubMed1981

Measurement of diethylstilbestrol in plasma from patients with cancer of the prostate.

A specific radioimmunoassay has been developed for diethylstilbestrol (DES), using an antiserum raised against DES monocarboxymethyl ether and a tritium-labeled radioligand. Prior to radioimmunoassay, a fraction enriched in DES is obtained from a dichloroethane extract of plasma using Sephadex LH-20. The specificity of the assay is good, and the sensitivity (130 pg/ml) is adequate for accurate determination of DES in plasma from prostatic cancer patients treated with the drug. The precision is satisfactory, with an interassay coefficient of variation of approximately 10% at concentrations of approximately 1 ng/ml, and the blank values are negligible. Excellent agreement (r = 0.96) is observed between data obtained by radioimmunoassay and those obtained by a procedure using gas chromatography-high-resolution mass spectrometry. DES concentrations in the plasma of six treated (1 mg DES three times daily) patients were in the range 0.15 to 6.0 ng/ml. Increases in plasma concentration were observed within 2 hr of administration, with secondary rises occurring 5 to 6 hr later. Plasma testosterone concentrations were low in four of the patients; in a single subject, relatively high levels of testosterone were further elevated following administration of luteinizing hormone-releasing hormone.

Circadian Rhythm↗
PubMed1980

Plasma spermidine concentrations in patients with tumours of the breast or prostate or testis.

Plasma spermidine concentrations were measured by radioimmunoassay in normal subjects and in patients with various tumours of the breast, prostate or the testis. The sensitivity of the method was 0.45 pmol spermidine/20 microliter plasma and the cross reactivity was 13% with putrescine and 2% with spermine. Plasma spermidine concentrations were raised in 25% of the patients with prostatic cancer (mean concentration 316.7 +/- 240.69 nmol/l) and in 8% of the patients with benign prostatic hyperplasia (mean concentration 198.9 +/- 169.92 nmol/l). No correlation was found between elevated plasma levels of spermidine in the prostatic cancer patients and tumour stage or metastatic status of the patients. No correlation of plama spermidine concentrations and age was found in 61 normal male subjects (mean concentration 200.3 +/- 137.71 nmol/l plasma). Only 29% of the patients with breast carcinoma had elevated levels of spermidine compared to normal female subjects. Plasma spermidine concentrations did not correlate with clinical stage or oestrogen receptor status in these patients. Patients with testicular tumours had elevated mean concentrations of plasma spermidine. One out of five patients with seminoma of the testis and six out of 16 patients with teratoma of the testis had significantly elevated concentrations.

Adult↗
PubMed1980

Tissue androgen concentrations in golden hamsters with benign prostatic tumours.

Using gas chromatography-high resolution mass spectrometry with selected ion detection, the concentrations of testosterone, 5alpha-dihydrotestosterone, androsterone, 5alpha-androstane-3alpha,17beta-diol, 5alpha-androstane-3beta,17alpha-diol and 5alpha-androstane-3beta,17beta-diol were measured in the dorsal and ventral prostates of two strains of golden hamster (Mesocricetus auratus) at various ages from 60 to 250 days. The tissue concentrations from a control strain were compared with those of the BIO 87.2 strain of hamster, the latter developing benign hyperplasia of the prostate between 90 and 120 days of age. Marked increases in the concentration of total 5alpha-androstanediols in both prostatic lobes of the BIO 87.2 strain were detected, with the highest level of over 345 nmol/g protein being found at 200 days of age. In comparison, the control strain showed a less pronounced increase in concentration at 150 days. Increases in total 5alpha-androstanediols were mainly associated with increases in the concentration of 5alpha-androstane-3alpha,17beta-diol. Concentrations of testosterone in prostatic tissue were also found to increase in the BIO 87.2 animals with peak values being seen at 200 days. Increases in concentration of androsterone were observed by 150 days and these levels were maintained up to 250 days of age. Control animals showed no comparable increases in testosterone and androsterone during the time-course studied. Surprisingly, no significant variation in 5alpha-dihydrotestosterone concentration was detected in either strain from 60 to 250 days although levels were slightly but consistently higher in the BIO 87.2 strain. There were no significant fluctuations in any of the androgens assayed either before or during tumour development. The increases in 5alpha-androstane-3alpha,17beta-diol, testosterone and androsterone were detected only after tumours had become established.

Androgens↗
PubMed1979

Plasma spermine concentrations of patients with benign and malignant tumours of the breast or prostate.

A radioimmunoassay has been developed for the measurement of plasma spermine concentrations. The sensitivity of the method is 1 pmol spermine/100 microliters plasma and the crossreactivity was 12% with spermidine and 0.18% with putrescine. Plasma spermine levels of patients with benign and malignant tumours of the prostate or breast were measured using this technique. Concentrations were only occasionally elevated in patients with prostatic tumours compared to normal individuals and there was no difference between those men with benign (mean concn. 0.21 +/- 0.14 nmol/ml plasma) or malignant (mean concn. 0.21 +/- 0.11 nmol/ml plasma) tumours. Only 17% of the patients with breast carcinoma had elevated levels of spermine, although there was a significant difference in the concentrations of the breast cancer group of patients compared to normals. No correlation was found between elevated plasma spermine concentrations and tumour grade or presence or spread of metastases in those patients.

Adolescent↗
PubMed1979

The determination of testosterone in hamster prostate by gas chromatography mass spectrometry with selected metastable peak monitoring.

Quantitative analyses of testosterone, as the methyl oxime t-butyldimethylsilyl ether, are performed by gas chromatography mass spectrometry with selected monitoring of the metastable peak corresponding to the fragmentation [M]+. leads to [M-C4H9]+ in the field free region preceding the electric sector of a double focusing mass spectrometer. A detection limit of c. 30 pg is observed during analyses of the standard compound. The method is applied to the quantitative determination of testosterone in extracts of prostatic tissue from the golden hamster, using epitestosterone as the internal standard. The analytical specificity is similar to that achieved during gas chromatography high resolution mass spectrometry with selected ion detection of [M]+. ions; gas chromatography low resolution mass spectrometry is of inadequate specificity.

Animals↗
PubMed1977

The ultrastructure of Rhesus monkey prostate.

An ultrastructural study of immature and mature rhesus monkey prostate is described and a comparison is made with human tissue. The immature gland consists of largely undifferentiated epithelium showing little or no secretory activity. The mature gland exhibits the general characteristics of prostates of the other species studied. Columnar epithelial cells and undifferentiated basal cells are observed. The two lobes of the gland show several differences, the caudal lobe being rich in secretory granules, with the cranial lobe consisting of taller vacuolated cells. The description provides a basis for comparison with ultrastructural changes produced during in vivo and in vitro experimentation and with characteristics of normal and diseased human prostate.

Age Factors↗
PubMed1976

The effect of ACTH on plasma testosterone and androstenedione concentrations in patients with prostatic carcinoma.

The effect of Synacthen (beta1-24-corticotrophin) on plasma testosterone and 4-androstene-3, 17-dione concentrations in untreated patients with prostatic carcinoma, and in patients receiving endocrine therapy is described. An established specific radioimmunoassay was used for the measurement of testosterone, and a radioimmunoassay for 3-androstene-3,17-dione using thin layer chromatography has been developed. Administration of Synacthen resulted in a fall in testosterone in untreated patients, but a rise in 4-androstene-3,17-dione was observed. The plasma concentration of testosterone in all treated patients increased after administration of Synacthen. An increased concentration of plasma 4-androstene-3,17-dione was also observed in these treated patients after Synacthen, but the magnitude of the response was not significantly different from that of untreated patients. The work provides further evidence that in the patient being treated with oestrogen for carcinoma of the prostate a rise in plasma testosterone concentration will result from an increased secretion of ACTH.

Adrenocorticotropic Hormone↗
PubMed1976

Plasma steroid and protein hormone concentrations in patients with prostatic carcinoma, before and during oestrogen therapy.

Plasma testosterone, androstenedione, oestradiol-17beta, follicle stimulating hormone (FSH) and luteinizing hormone (LH) were not significantly different in patients with prostatic cancer, with benign prostatic hyperplasia or in patients without prostatic disease. Plasma prolactin concentrations were significantly lower in the patients with benign disease than those with prostatic carcinoma. Endocrine therapy in the form of stilboestrol administration significantly decreased plasma levels of testosterone, oestradiol-17beta, FSH and LH within 7 days of the treatment. After 7 days therapy prolactin levels increased significantly in all patients studied. Changes in growth hormone concentrations were more varied in response to stilboestrol, being elevated in several patients and remaining unchanged in others. Treatment of a few prostatic carcinoma patients who were receiving stilboestrol therapy with CB154, an inhibitor of prolactin secretion, brought an immediate decrease in prolactin levels which was was sustained. Plasma testosterone, androstenedione and growth hormone were unchanged in these patients but a significant decrease in plasma oestradiol-17beta was noted in two patients during CB154 administration.

Aged↗