Biomedical subjects

T G Cooper

Publications and source records attributed to T G Cooper.

At least 181 records · Page 10Linked to original sources

PubMed1991

The evaluation of markers of prostatic function.

The concentrations of three secretory proteins of the human prostate, including prostatic secretory protein of 94 amino acid residues (PSP94), prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP), were measured by enzyme-linked immunosorbent assay (ELISA) in semen from a collective of patients suffering from various inflammatory diseases of the genital tract. In addition, levels of the conventional markers citrate, glucosidase and fructose were determined. As compared with semen from men exhibiting no inflammatory condition, only levels of glucosidase in cases of epididymitis and concentrations of PSP94 in the collective suffering from prostatitis showed significant reductions. The changes in the secretion of PSA, PAP, fructose and citrate in the semen of patients with inflammation of genital tract tissue were not significant at the 95% range of confidence.

Acid Phosphatase↗

PubMed1991

Hyaluronic acid as a medium for human sperm migration tests.

Hyaluronic acid was used as a substitute for human cervical mucus as a medium for sperm migration since its viscosity, molecular weight and structure are similar to constituent glycoproteins of human cervical mucus. Parameters of sperm motility were comparable in human cervical mucus and hyaluronate as measured by a computerized sperm motion analysis system (Hamilton-Thorn 2030 and Strömberg-Mika System). Sperm migration rates were also similar in human cervical mucus, bovine mucus and hyaluronic acid and the reproducibility was best in hyaluronic acid. Sperm survival for 24 h was maintained in human cervical mucus and hyaluronic acid but not in bovine mucus. The use of hyaluronic acid in sperm migration tests is recommended.

Animals↗

PubMed1991

Variations in semen parameters from fathers.

Semen volume, pH, sperm characteristics and the ejaculate content of six compounds secreted by the epididymides, prostate and seminal vesicles are presented for several semen samples from 25 men (mean age 31 years) who, without clinical assistance, had fathered children within the previous 29 months. There was a large variation both within and between individual's samples for concentrations and amounts per ejaculate of all parameters except pH. The range including 96% of all values from these fertile men are presented as standards against which samples from infertile men could be compared. Lower limits (combined arithmetic means minus twice the combined within- and between-father standard deviation) were: for semen volume, 1.9 ml; for semen pH, 7.4; for total sperm count, 39 X 10(6); for normal morphological forms, 42%; for motility (WHO grades) a, 4%; b, 19%; c, 1%; d, 19%; for curvilinear velocity, 27 microns/s; for total glucosidase, 27 mU/ejaculate; for neutral alpha-glucosidase, 17 mU/ejaculate; for L-carnitine, 0.4 mumol/ejaculate; for glycerophosphocholine, 2.4 mumol/ejaculate; for fructose, 15 mumol/ejaculate; for citrate, 30 mumol/ejaculate; for zinc, 2.8 mumol/ejaculate.

Adult↗

PubMed1991

Non-specific uptake of IgG by rat epididymal tubules in vitro.

Tubules isolated from the initial segment, caput and corpus regions of the rat epididymis were incubated for 4 h in medium containing rat IgG or bovine-serum-albumin (10 mg ml-1) and processed for light microscopy immunocytochemistry using gold-labelled anti-rat IgG and silver staining or peroxidase/anti-peroxidase techniques. Distribution of IgG was confined to the peritubular matrix only, with no detectable uptake into the epithelium or lumen. In tubules incubated with rat IgG coupled to gold particles as tracer and fixed for electron microscopy, the IgG-gold complex failed to penetrate to the base of the epithelium. When IgG-peroxidase conjugates were used, sparse enzyme activity was localized in small basal and apical vesicles and multivesicular bodies of the principal cells. However, this uptake could not be inhibited by the presence of a 30-fold excess of non-labelled IgG, and the same distribution of enzyme activity was also observed when tubules were incubated with a similar activity of horseradish peroxidase alone. These findings indicate that there is no detectable receptor-mediated transport of IgG across the epididymal epithelium, although non-selective transfer could occur via fluid-phase endocytosis.

Animals↗

PubMed1991

DAL82, a second gene required for induction of allantoin system gene transcription in Saccharomyces cerevisiae.

Several highly inducible enzyme activities are required for the degradation of allantoin in Saccharomyces cerevisiae. Induction of these pathway enzymes has been shown to be regulated at transcription, and response to inducer is lost in dal81 and dal82/durM mutants. The similar phenotypes generated by dal81 and dal82 mutations prompted the question of whether they were allelic. We demonstrated that the DAL81 and DAL82 loci are distinct, unlinked genes situated on chromosomes IX and XIV. DAL82 gene expression did not respond to induction by the allantoin pathway inducer or to nitrogen catabolite repression. Expression was also not significantly affected by mutation of the dal80 locus. From the nucleotide sequence of the DAL82 gene, we deduced that it encodes a protein with a mass of 29,079 Da that may possess the structural motifs expected of a regulatory protein. This protein was shown to be required for the function mediated by the cis-acting upstream induction sequence situated in the 5'-flanking regions of the inducible allantoin pathway genes.

Allantoin↗

PubMed1991

Saturation mutagenesis of the UASNTR (GATAA) responsible for nitrogen catabolite repression-sensitive transcriptional activation of the allantoin pathway genes in Saccharomyces cerevisiae.

Saturation mutagenesis of the UASNTR element responsible for GLN3-dependent, nitrogen catabolite repression-sensitive transcriptional activation of allantoin pathway genes in yeast cells identified the dodecanucleotide sequence 5'-TTNCTGATAAGG-3' as the minimum required for UAS activity. There was significant flexibility in mutant sequences capable of supporting UAS activity, which correlates well with the high variation in UASNTR homologous sequences reported to be upstream of the DAL and DUR genes. Three of nine UASNTR-like sequences 5' of the DAL5 gene supported high-level transcriptional activation. The others, which contained nonpermissive substitutions, were not active.

Allantoin↗

PubMed1991

Participation of ABF-1 protein in expression of the Saccharomyces cerevisiae CAR1 gene.

DNA fragments previously shown to be required for expression of the CAR1 (arginase) gene in Saccharomyces cerevisiae and to support transcriptional activation of a reporter gene in a heterologous expression vector were shown to bind purified regulatory protein ABF-1. Two ABF-1 sites were identified in the CAR1 upstream region, one to which ABF-1 protein bound with high affinity and a second to which it bound much less avidly. The higher-affinity ABF-1 binding site upstream of CAR1 was an effective competitor of the HMRE, ARS1 B domain, and COR2-GFI binding sequences for protein binding. Point mutations in the CAR1 high-affinity ABF-1 binding site resulted in a 12-fold loss of transcriptional activation of a reporter gene compared with the wild-type CAR1 DNA fragment. These data are consistent with the suggestion that ABF-1 protein is one of the transcription factors involved in expression of the CAR1 gene.

Arginase↗

PubMed1991

Upstream induction sequence, the cis-acting element required for response to the allantoin pathway inducer and enhancement of operation of the nitrogen-regulated upstream activation sequence in Saccharomyces cerevisiae.

Expression of the DAL2, DAL4, DAL7, DUR1,2, and DUR3 genes in Saccharomyces cerevisiae is induced by the presence of allophanate, the last intermediate of the allantoin degradative pathway. Analysis of the DAL7 5'-flanking region identified an element, designated the DAL upstream induction sequence (DAL UIS), required for response to inducer. The operation of this cis-acting element requires functional DAL81 and DAL82 gene products. We determined the DAL UIS structure by using saturation mutagenesis. A specific dodecanucleotide sequence is the minimum required for response of reporter gene transcription to inducer. There are two copies of the sequence in the 5'-flanking region of the DAL7 gene. There are one or more copies of the sequence upstream of each allantoin pathway gene that responds to inducer. The sequence is also found 5' of the allophanate-inducible CAR2 gene as well. No such sequences were detected upstream of allantoin pathway genes that do not respond to the presence of inducer. We also demonstrated that the presence of a UIS element adjacent to the nitrogen-regulated upstream activation sequence significantly enhances its operation.

Allantoin↗

PubMed1991

Expression of the DAL80 gene, whose product is homologous to the GATA factors and is a negative regulator of multiple nitrogen catabolic genes in Saccharomyces cerevisiae, is sensitive to nitrogen catabolite repression.

We have cloned the negative regulatory gene (DAL80) of the allantoin catabolic pathway, characterized its structure, and determined the physiological conditions that control DAL80 expression and its influence on the expression of nitrogen catabolic genes. Disruption of the DAL80 gene demonstrated that it regulates multiple nitrogen catabolic pathways. Inducer-independent expression was observed for the allantoin pathway genes DAL7 and DUR1,2, as well as the UGA1 gene required for gamma-aminobutyrate catabolism in the disruption mutant. DAL80 transcription was itself highly sensitive to nitrogen catabolite repression (NCR), and its promoter contained 12 sequences homologous to the NCR-sensitive UASNTR. The deduced DAL80 protein structure contains zinc finger and coiled-coil motifs. The DAL80 zinc finger motif possessed high homology to the transcriptional activator proteins required for expression of NCR-sensitive genes in fungi and the yeast GLN3 gene product required for functioning of the NCR-sensitive DAL UASNTR. It was also homologous to the three GATAA-binding proteins reported to be transcriptional activators in avian and mammalian tissues. The latter correlations raise the possibility that both positive and negative regulators of allantoin pathway transcription may bind to similar sequences.

Allantoin↗

PubMed1991

The DAL81 gene product is required for induced expression of two differently regulated nitrogen catabolic genes in Saccharomyces cerevisiae.

We demonstrate that the DAL81 gene, previously thought to be specifically required for induced expression of the allantoin pathway genes in Saccharomyces cerevisiae, functions in a more global manner. The data presented show it to be required for utilization of 4-aminobutyrate as a nitrogen source and for 4-aminobutyrate-induced increases in the steady-state levels of UGA1 mRNA. The DAL81 gene encodes a 970-amino-acid protein containing sequences homologous to the Zn(II)2Cys6 motif and two stretches of polyglutamine residues. Deletion of sequences homologous to the Zn(II)2Cys6 motif did not result in a detectable loss of function. On the other hand, loss of one of the polyglutamine stretches, but not the other, resulted in a 50% loss of DAL81 function.

Amino Acid Sequence↗

PubMed1991

Intra- and extracellular pH of the brain in vivo studied by 31P-NMR during hyper- and hypocapnia.

Studies were performed to determine the pH relationships among the extracellular, intracellular, and arterial blood compartments in the brain in vivo. Resolution of the extracellular monophosphate resonance peak from the intracellular peak in 31P nuclear magnetic resonance (NMR) spectra of sheep brain with the calvarium intact enabled pH measurement in these respective compartments. Sheep were then subjected to both hyper- and hypoventilation, which resulted in a wide range of arterial PCO2 and pH values. Linear regression analysis of pH in these compartments yielded slopes of 0.56 +/- 0.05 for extracellular pH (pHe) vs. arterial pH, 0.43 +/- 0.078 for intracellular pH (pHi) vs. pHe, and 0.23 +/- 0.056 for pHi vs. arterial pH. These data indicate that CO2 buffering capacity is different and decreases from the intracellular to extracellular to arterial blood compartments. Separation of the extracellular space from the vascular space may be a function of the blood-brain barrier, which contributes to the buffering capability of the extracellular compartment. A marked decrease in the pH gradient between the extracellular and intracellular space occurs during hypercarbia and may influence mechanisms of central respiratory control.

Animals↗

PubMed1991

The urea amidolyase (DUR1,2) gene of Saccharomyces cerevisiae.

The DNA sequence of the urea amidolyase (DUR1,2) gene from S. cerevisiae has been determined. The polypeptide structure deduced from the DNA sequence contains 1,835 amino acid residues and possesses a calculated weight of 201,665 daltons which favorably correlates with that predicted from compositional analysis of purified protein (1,881 amino acid residues and a molecular weight of 203,900). The C-terminal 57 residues of the polypeptide exhibit significant homology with similarly situated sequences found in five other biotin carboxylases whose primary structures have been determined or deduced from protein and DNA sequence data, respectively. Major S1 nuclease protection fragments derived from DUR1,2 RNA-DNA hybrids exhibit apparent termini at positions -140 and -141 upstream of the coding region. The termini of minor protection fragments also occur at eleven other positions as well.

Amino Acid Sequence↗

PubMed1990

Improved assays of alpha-lactalbumin and galactosyltransferase.

The development and evaluation of a method for the determination of galactosyltransferase and alpha-lactalbumin activities using the addition of Dowex resin to the sample to separate substrate from products are described. For both assays galactosyltransferase activity was optimized by the addition of detergent, and relevant control incubations were included. The assay conditions were optimized for epididymal tissue and standards, and the assays were validated for accuracy and specificity with authentic bovine proteins and lactating rat mammary gland homogenates. Galactosyltransferase and alpha-lactalbumin activities in tissues were dependent on the extraction procedure used. Epididymal and testicular homogenates reduced the slopes of internal standards of galactosyltransferase but only testicular homogenates depressed slopes of internal standards of alpha-lactalbumin, necessitating the use of internal standards in the validation of the assays.

Animals↗

PubMed1990

In defense of a function for the human epididymis.

In view of reports that the human epididymis may play no role in human fertility, literature on the fertilizing capacity of epididymal spermatozoa was reviewed. The survey indicates that under the circumstances of their retrieval, human epididymal and testicular spermatozoa may have the ability to fertilize human eggs both in vivo and in vitro. Although the "fertility profile" of the normal epididymis cannot be explored in man, a fair assumption would be that fertilizing capacity develops fully in the distal part of the tract, judging from the higher motility and egg fusing ability of sperm taken from these regions of unobstructed tissue. Motility and fertilizing capacity observed with IVF or artificial insemination, in which sperm are obtained from obstructed ducts, may occur at a level in the tract more proximal than normal, as in animals. The pregnancies resulting from aspiration of spermatozoa from, or anastomosis of the vas deferens to, the efferent ducts are of great clinical interest, but the pathological state of the tissue precludes definitive statements about the functioning of a normal epididymis. In the former case, the immediate origin of the fertilizing spermatozoon and the nature of the secretions previously bathing it are unknown and in the latter case the time needed before pregnancies occur is much greater than anticipated had fertile sperm been present in the proximal epididymis. The evidence supports neither the view that testicular sperm are inherently fertile nor that a simple aging of sperm cells is sufficient for the fertilizing potential of spermatozoa to be realized. It emphasizes, rather, the importance of the environment to which the sperm cells are subjected. Under abnormal conditions other accessory glands may secrete compounds that are necessary for the maturation of spermatozoa. Before more information is known of the exact situation existing, or having existed, in pathological human tissues from which fertilizing human spermatozoa can be obtained, great caution should be exercised in interpreting the results of pregnancies arising from the in vivo and in vitro insemination of testicular or epididymal spermatozoa.

Animals↗

PubMed1990

Histochemical localization and quantification of alpha-glucosidase in the epididymis of men and laboratory animals.

The seminal marker of epididymal function alpha-1, 4-glucosidase was localized histochemically in the cytoplasm of the efferent duct epithelium and the brush border of the entire length of the human epididymis. Quantification using the specific inhibitor castanospermine revealed strongest activity in the corpus and cauda regions. Selective inhibition of the brush border enzyme activities by maltotriose identified these as the neutral isoenzymes. Despite detection of alpha-glucosidase in the renal tubules of all the animals studied, the enzyme was not detectable in epididymides of hamsters or mice. In rabbits and monkeys, it was absent from the entire brush border but present weakly in the cytoplasm of the proximal epididymides. An enzyme distribution pattern similar to that in the human epididymis was found in rats, except for the absence of histochemical staining at pH 6.5 from the initial segment and distal cauda epididymidis. Experiments in which endogenous testosterone was depleted in rats demonstrated the dependence of epididymal alpha-glucosidase on androgen, albeit with a low sensitivity. This study suggests the rat to be a suitable model for the investigation of the role of epididymal alpha-glucosidase in fertility.

Alkaloids↗

PubMed1990

Presence and distribution of leucocyte subsets in the murine epididymis after vasectomy.

Male mice were vasectomized by 'open-ended' or 'closed' techniques. After 4 weeks the cell-mediated immune reactions were compared with those of sham-operated animals by immunohistochemical localization of leucocytes, using specific monoclonal antibodies. Macrophages and MHC class II antigen-positive cells were the major cell types to appear in all regions of the epididymis after both types of operation. There was recruitment of T-helper/inducer leucocytes but not of T-suppressor-cytotoxic cells. An increased presentation of macrophage-migration inhibiting factor antigen appeared in interstitial and peritubular locations. After 'closed' and 'open-ended' vasectomy granulomata developed in the epididymis. The sperm-containing lumen of these granulomata was invaded by macrophages, MHC class II-positive cells and T-helper/inducer lymphocytes. This mouse model thus reveals a significant epididymal inflammatory response of the epididymis to vasectomy.

Animals↗

PubMed1990

Improvement in the assessment of human epididymal function by the use of inhibitors in the assay of alpha-glucosidase in seminal plasma.

Seminal alpha-glucosidase has been used clinically as a marker of epididymal function. In this study enzyme inhibitors were used to increase the specificity of the human seminal alpha-glucosidase assay and improve its diagnostic value as an indicator of distal epididymal occlusion in cases of azoospermia. Sodium dodecylsulphate was added to the sample to eliminate the interfering acid isoenzyme secreted by the prostate gland, and castanospermine was used with semen pools to provide a semen blank for the assay by eliminating non-glucosidase-regulated degradation of the substrate. With both inhibitors included in the assay, glucosidase activity in semen samples from 17 fathers was measured to provide reference values for the clinic (lower threshold 18 mU per ejaculate). With the improved assay glucosidase was non-detectable in 8 out of 11 cases of proven and 5 out of 8 cases of suspected ductal obstruction; other azoospermic patients with distal occlusion had values below 11 mU per ejaculate.

Acarbose↗

PubMed1990

The influence of inflammation of the human male genital tract on secretion of the seminal markers alpha-glucosidase, glycerophosphocholine, carnitine, fructose and citric acid.

Biochemical analysis was made of specific accessory gland products in the ejaculates of 362 men suffering from various acute inflammatory diseases of the reproductive tract and 33 normozoospermic patients acting as controls. The ejaculate content of the epididymal markers alpha-glucosidase and L-carnitine, but not glycerophosphocholine, was significantly reduced in ejaculates from men with epididymitis; citric acid was reduced in men suffering from prostatitis; both citric acid and alpha-glucosidase were reduced in men suffering from adnexitis. The ejaculate content of epididymal and prostatic markers in prostato-urethritis (adnexitis), where the exact localization of the inflammation was unclear, was not as low as in epididymitis or prostatitis. Seminal vesicle function, as judged from semen volumes and seminal fructose, was not different in these groups of patients. The results, although strongly related to the clinical diagnosis, were unrelated to the microbiological flora of the semen and indicate that both the epididymis and the prostate glands are involved in some forms of adnexitis.

Adolescent↗