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T G Cooper

Publications and source records attributed to T G Cooper.

At least 73 records · Page 4Linked to original sources
PubMed1999

Experience with external quality control in spermatology.

Results are presented from participation in an external quality control (EQC) programme for semen analysis (UK NEQAS). Formalin-fixed semen samples and videotapes of motile spermatozoa were distributed four times a year over a 3-4 year period. Over the entire period there was close agreement for sperm concentration with, initially, the average of values from the other groups participating in the scheme, and later, values designated as reference values obtained from six laboratories of several chosen that consistently agreed with each other. The initial underestimation of the percentage of normal forms was abolished at the time of change in derivation of designated values and this largely eliminated the difference to establish closer agreement with the designated values. A consistent bias in the assessment of different categories of progressive sperm motility appeared to be resolved by a conscious decision to consider most spermatozoa as grade b and the exceptions as grade a, rather than the converse. Feedback of results to the technicians of the laboratory participating in an external quality control programme leads to reappraisal of subjective evaluation and to harmonization of results between laboratories.

Fixatives↗
PubMed1999

Antioxidant treatment of patients with asthenozoospermia or moderate oligoasthenozoospermia with high-dose vitamin C and vitamin E: a randomized, placebo-controlled, double-blind study.

In a randomized, placebo-controlled, double-blind study we investigated whether high-dose oral treatment with vitamins C and E for 56 days was able to improve semen parameters of infertile men. Ejaculate parameters included semen volume, sperm concentration and motility, and sperm count and viability. Thirty-one patients without genital infection but with asthenozoospermia (< 50% motile spermatozoa) and normal or only moderately reduced sperm concentration (> 7 x 10(6) spermatozoa/ml) (according to WHO criteria) were examined. To investigate the influence of the epididymal storage period on semen parameters, the patients were asked to deliver two semen samples with abstinence times of 2 and 7 days both before and at the end of vitamin treatment. After randomization, the patients received either 1000 mg vitamin C and 800 mg vitamin E (n = 15) or identical placebo capsules (n = 16). No changes in semen parameters were observed during treatment, and no pregnancies were initiated during the treatment period. Combined high-dose antioxidative treatment with vitamins C and E did not improve conventional semen parameters or the 24-h sperm survival rate. Prolonged abstinence time increased ejaculate volume (P < 0.05), sperm count (P < 0.05), sperm concentration (P < 0.05) and the total number of motile spermatozoa (P < 0.05).

Administration, Oral↗
PubMed1999

Infertile spermatozoa of c-ros tyrosine kinase receptor knockout mice show flagellar angulation and maturational defects in cell volume regulatory mechanisms.

Homozygous c-ros knockout male mice that lack prepubertal differentiation of the epididymal initial segment are healthy but sterile, despite normal sperm production and mating. Detailed computerized analysis of the motility of spermatozoa maturing in the epididymis revealed only minor defects. However, the majority of motile mature sperm released from the cauda epididymidis showed various extents of flagellar angulation that could not be corrected by raising extracellular osmolality. Measurement of the osmolality of cauda epididymal fluid showed no difference from the wild type. Studies in wild-type mice indicated a maturational change in the ability of motile sperm to maintain straight flagella during incubation, but angulation was induced in cauda sperm by the volume-sensitive ion channel blockers quinine, 5-nitro-2-(3-phenylpropylamino)-benzoic acid and BaCl(2), or by exposure to hypotonic media. Flagellar angulation, induced in the wild type or intrinsic to the knockout, was relieved upon demembranation by Triton X-100, confirming that it was a cell swelling phenomenon. A lack of response of immature wild-type sperm and mature knockout sperm to the channel blockers suggests that there is normally a development of the volume regulatory mechanisms upon maturation that is defective in sperm from the knockout animal. The resultant flagellar angulation may account for the reduction in sperm numbers in the oviduct of mated females and the failure to fertilize in vivo.

Animals↗
PubMed1999

The dual-specificity protein phosphatase Yvh1p acts upstream of the protein kinase mck1p in promoting spore development in Saccharomyces cerevisiae.

Diploid Saccharomyces cerevisiae cells induce YVH1 expression and enter the developmental pathway, leading to sporulation when starved for nitrogen. We show that yvh1 disruption causes a defect in spore maturation; overexpression of MCK1 or IME1 suppresses this yvh1 phenotype. While mck1 mutations are epistatic to those in yvh1 relative to spore maturation, overexpression of MCK1 does not suppress the yvh1 slow-vegetative-growth phenotype. We conclude that (i) Yvh1p functions earlier than Mck1p and Ime1p in the signal transduction cascade that regulates sporulation and is triggered by nitrogen starvation and (ii) the role of Yvh1p in gametogenesis can be genetically distinguished from its role in vegetative growth.

Dual-Specificity Phosphatases↗
PubMed1999

Synergistic operation of the CAR2 (Ornithine transaminase) promoter elements in Saccharomyces cerevisiae.

Dal82p binds to the UIS(ALL) sites of allophanate-induced genes of the allantoin-degradative pathway and functions synergistically with the GATA family Gln3p and Gat1p transcriptional activators that are responsible for nitrogen catabolite repression-sensitive gene expression. CAR2, which encodes the arginine-degradative enzyme ornithine transaminase, is not nitrogen catabolite repression sensitive, but its expression can be modestly induced by the allantoin pathway inducer. The dominant activators of CAR2 transcription have been thought to be the ArgR and Mcm1 factors, which mediate arginine-dependent induction. These observations prompted us to investigate the structure of the CAR2 promoter with the objectives of determining whether other transcription factors were required for CAR2 expression and, if so, of ascertaining their relative contributions to CAR2's expression and control. We show that Rap1p binds upstream of CAR2 and plays a central role in its induced expression irrespective of whether the inducer is arginine or the allantoin pathway inducer analogue oxalurate (OXLU). Our data also explain the early report that ornithine transaminase production is induced when cells are grown with urea. OXLU induction derives from the Dal82p binding site, which is immediately downstream of the Rap1p site, and Dal82p functions synergistically with Rap1p. This synergism is unlike all other known instances of Dal82p synergism, namely, that with the GATA family transcription activators Gln3p and Gat1p, which occurs only in the presence of an inducer. The observations reported suggest that CAR2 gene expression results from strong constitutive transcriptional activation mediated by Rap1p and Dal82p being balanced by the down regulation of an equally strong transcriptional repressor, Ume6p. This balance is then tipped in the direction of expression by the presence of the inducer. The formal structure of the CAR2 promoter and its operation closely follow the model proposed for CAR1.

5' Untranslated Regions↗
PubMed1999

Control of nitrogen catabolite repression is not affected by the tRNAGln-CUU mutation, which results in constitutive pseudohyphal growth of Saccharomyces cerevisiae.

Saccharomyces cerevisiae responds to nitrogen availability in several ways. (i) The cell is able to distinguish good nitrogen sources from poor ones through a process designated nitrogen catabolite repression (NCR). Good and poor nitrogen sources do not demonstrably affect the cell cycle other than to influence the cell's doubling time. (ii) Nitrogen starvation promotes the initiation of sporulation and pseudohyphal growth. (iii) Nitrogen starvation strongly affects the cell cycle; nitrogen-starved cells arrest in G1. A specific allele of the SUP70/CDC65 tRNAGln gene (sup70-65) has been reported to be defective in nitrogen signaling associated with pseudohyphal formation, sporulation, and NCR. Our data confirm that pseudohyphal growth occurs gratuitously in sup70-65 mutants cultured in nitrogen-rich medium at 30 degrees C. However, we find neither any defect in NCR in the sup70-65 mutant nor any alteration in the control of YVH1 expression, which has been previously shown to be specifically induced by nitrogen starvation.

Gene Expression Regulation, Fungal↗
PubMed1999

Silent meniscal abnormalities in athletes: magnetic resonance imaging of asymptomatic competitive gymnasts.

BACKGROUND: Magnetic resonance imaging (MRI) produces exceptionally detailed images of the intra-articular structures of the knee. Recognising the range of MRI appearances within a normal population is therefore necessary in order to avoid attributing a greater significance to these than is clinically justified. OBJECTIVE: To compare MRI appearances in asymptomatic gymnasts with those in a less active population in order to identify findings that may be seen in the absence of significant pathology and thereby aid the clinical management of this athletic group. METHODS: MR images were obtained from 24 knees of asymptomatic competitive American collegiate gymnasts aged 18-22. The menisci were evaluated according to established grading criteria, and compared with a group of controls matched for age and sex. RESULTS: Grade 3 intrameniscal signal abnormalities are considered to be highly correlated with meniscal tears. When compared with control group, the experimental group of gymnasts had a significantly different distribution (p<0.001) of grade 3 intrameniscal signal changes, preferentially involving the lateral meniscus. The overall incidence of grade 3 changes (13%) in gymnasts was not, however, significantly different from the incidence in the controls. CONCLUSIONS: A knowledge of these MRI appearances is important when evaluating the lateral menisci within this group of athletes to prevent unnecessary treatment or intervention. This is particularly pertinent when the imaging findings do not closely correlate with the site of symptoms.

Adolescent↗
PubMed1999

Approaches to post-testicular contraception.

The induction of infertility in males of several species through epididymal interference is more difficult to achieve by reduction of the amounts of epididymal secretions (eg alpha-glucosidase, L-carnitine) or immunological interference with secreted proteins (eg D/E, P34H, P26h) than by direct actions of drugs on sperm function (eg inhibition of glyceraldehyde 3-phosphate dehydrogenase by chloro-compounds). The latter approach holds promise for mankind as human sperm are susceptible to glycolytic inhibition. Future contraceptive developments may arise from production of targeted inhibitors, research on the displacement of sperm proteins in the epididymis and interference with sperm plasma membrane ion channels.

Animals↗
PubMed1998

Molecular cloning and expression of rat contraception associated protein 1 (CAP1), a protein putatively involved in fertilization.

Epididymal fluid from rats rendered infertile by oral administration of ornidazole contains a protein CAP1 (contraception-associated protein 1) that is absent from epididymal fluid, but present on epididymal sperm, from fertile vehicle-treated rats. The gene for CAP1 has been isolated from a rat testis cDNA library and its expression investigated in different tissues. The deduced protein sequence of CAP1 contains 189 amino-acid residues and database searches revealed a high degree of homology (83-95%) with human and mouse DJ-1 at the nucleotide and amino acid levels. Northern blot hybridisation from different rat tissues indicated that CAP1 is encoded by a 1.6-kilobase RNA transcript and seems to be ubiquitiously expressed in the rat with a high level of expression in the testis.

Adult↗
PubMed1998

Efficient PCR-based random mutagenesis of sub-genic (100 bp) DNA fragments.

Here we describe a method for performing a PCR-driven random mutagenesis of 100 bp DNA fragments that yields mutations at a useful frequency. The method is a modification of the manganese ion substitution PCR technique, and neither creates 'hot-spots' nor favors transition mutations over transversions.

DNA, Fungal↗
PubMed1998

Creatine kinase activity in human spermatozoa and seminal plasma lacks predictive value for male fertility in in vitro fertilization.

OBJECTIVE: To examine the predictive value of creatine kinase in human spermatozoa and seminal plasma from patients treated in an IVF program. DESIGN: Prospective, blind clinical study. SETTING: Male infertility clinic. PATIENT(S): Seventy-three patients and 32 fathers (age, <45 years). INTERVENTION(S): Determination of creatine kinase activity in seminal plasma, washed spermatozoa, and swim-up purified spermatozoa from patients treated in an IVF program. MAIN OUTCOME MEASURE(S): Creatine kinase activity in seminal plasma, washed spermatozoa, and swim-up purified spermatozoa. RESULT(S): Creatine kinase activity in washed spermatozoa correlated significantly with normal sperm morphology. No significant correlations were found between creatine kinase activity or creatine kinase isoenzyme ratio in seminal plasma, washed spermatozoa, or swim-up purified spermatozoa and success in the IVF program. The percentage of spermatozoa with normal morphology was significantly lower in patients whose sperm did not fertilize than in patients whose sperm did fertilize oocytes and in the control group of proven fathers. CONCLUSION(S): Total creatine kinase activity and creatine kinase isoenzyme distribution are not sperm function markers for prediction of male fertility in IVF treatment.

Adult↗
PubMed1998

Influence of sperm surface antibodies on spontaneous pregnancy rates.

OBJECTIVE: To determine the rates of spontaneous pregnancies among women whose infertile male partners had sperm surface antibodies. DESIGN: Retrospective analysis. SETTING: Infertility clinic of a university referral center. PATIENT(S): One hundred fifty-seven infertile couples; the male partner had IgA and/or IgG sperm surface antibody concentrations of >10%. INTERVENTION: None. MAIN OUTCOME MEASURE(S): Spontaneous pregnancy rates (PRs) over 6 years. RESULT(S): Spontaneous PRs correlated negatively with antibody concentrations. CONCLUSION(S): Although the chance of spontaneous pregnancy among women whose partners had sperm antibody concentrations of <50% was good, intracytoplasmic sperm injection should be recommended to patients with concentrations of >90%.

Female↗
PubMed1998

Standardization of sampling and staining methods for the morphometric evaluation of sperm heads in the Cynomolgus monkey (Macaca fascicularis) using computer-assisted image analysis.

Automated sperm morphology analysis (ASMA) technology has improved the assessment of sperm morphology, but the results depend on the use of adequate and standardized procedures. In this study the Sperm-Class Analyzer (SCA) ASMA system was used to assess sperm head morphometry in the Cynomolgus monkey and to evaluate the influence of sample size, intraslide variation, and the use of three staining techniques on the accuracy of image processing and sperm head morphometry. Haematoxylin is the staining technique of choice for Cynomolgus spermatozoa, as optimum contrast of sperm heads with the surrounding background allows efficient segmentation, i.e. sperm head boundary detection, making the image analysis process more accurate. The analysis of 100 spermatozoa is recommended since a larger sample size did not result in more accurate sperm head morphometry. There were no differences in either the percentage of correctly binarized sperm heads or sperm head dimensions among samples obtained from different zones of the slides, although differences in stain intensity (grey level) were detected. The measurements made on Haematoxylin, Diff-Quik and Hemacolor-stained slides yielded different values for all of the sperm head parameters under consideration. This result demonstrates that the procedures of fixation and staining significantly affect the dimensions of sperm heads.

Animals↗
PubMed1998

The appearance of basal cells in the developing murine epididymis and their temporal expression of macrophage antigens.

This work demonstrates similarities between epididymal basal cells and macrophages in the mouse. Light microscopic studies of the postnatal development of the murine epididymis showed that basal cells were not present before days 12, 14 and 16 in the cauda, caput and corpus epididymis, respectively. An increase in cell number per unit length of tubule perimeter was demonstrated in all segments between days 20 and 27, when testicular fluid and spermatozoa start entering the epididymis. In the adult, there were more basal cells per unit perimeter in the cauda than caput or corpus epididymis. Conspicuous and consistent expression by basal cells of antigens detected by antibodies against tissue-fixed macrophages (F4/80) and mature macrophages (Mac-1) occurred only after they became established within the epithelium. Basal cells in the cauda epididymis did not display either antigen in the adult, although they persisted in the caput region. Such developmental patterns are compatible with the hypothesis that basal cells play a role in immune defence against sperm autoantigens.

Animals↗
PubMed1998

Epididymal secretion of CD52 as measured in human seminal plasma by a fluorescence immunoassay.

A major secretory protein of the human epididymis that is taken up by maturing spermatozoa is homologous to the leukocyte antigen CD52. The epididymis was shown to be the sole source of CD52 in seminal fluid, since CD52 could be detected in seminal plasma from sperm-containing ejaculates and not in ejaculates of vasectomized patients by Western blot analysis. The glycoprotein is not expressed in the testes. A fluorescence immunobinding assay was developed to quantify the amount of epididymal secretion of CD52 in the seminal plasma of various groups of fertile and infertile patients. Donor spermatozoa bearing CD52 were used as binding site tracers for free anti-CD52 antibody remaining after it had adsorbed CD52 from the seminal plasma to be assayed. The level of subsequent antibody binding to spermatozoa was measured by flow cytometry and the extent of binding inhibition was compared to a reference pool of seminal plasma to provide relative amounts of CD52 in test seminal plasma. There were no correlations between seminal plasma CD52 concentration and any semen parameter tested, including sperm concentration, percentage motility, normal sperm morphology or the concentration of seminal neutral alpha-glucosidase, fructose and zinc. There was a slight tendency towards an inverse relationship with the amount of CD52 on spermatozoa, but this was not significant. No differences were found among groups of patients classified by their semen parameters or fertility status. These findings indicate that the epididymal specific supply of CD52 is not a limiting factor for CD52 uptake onto spermatozoa.

Adult↗
PubMed1998

Studies on the origin of redox enzymes in seminal plasma and their relationship with results of in-vitro fertilization.

Glutathione (GSH), GSH peroxidase (GPX), GSH reductase (GRD), superoxide dismutase (SOD) and catalase-like enzyme activity were quantified in seminal plasma from normozoospermic patients, men with known distal ductal occlusion, proven fathers and male partners of couples receiving in-vitro fertilization (IVF) treatment for both male and female causes. Glutathione was non-detectable (< 2.5 microM) in seminal plasma. None of the enzyme activities per unit volume were lower in semen from vasectomized men, suggesting that they did not originate substantially from the testis or epididymis. The strongest relationships between enzyme activities and accessory gland markers were between zinc and GRD (r = 0.678), SOD (r = 0.602) and GPX (r = 0.548), suggesting a largely prostatic origin of these enzymes. Only weak relationships between accessory gland markers and catalase-like activity suggested a multi-glandular source of this enzyme. There was no relationship between the activity of any of the enzymes in the IVF patients with their fertilization rates in vitro or the establishment of pregnancy after IVF. Nor was there any correlation of enzyme activity with the morphology and percentage of motile spermatozoa in semen or with the percentage motility of spermatozoa immediately after swim-up or after overnight incubation. These findings suggest that the protective enzymes in the seminal plasma are contributed largely by the prostate and little by the epididymis, and that in most cases of IVF, they have no major influence on the outcome.

Adult↗
PubMed1998

Shedding of a rat epididymal sperm protein associated with infertility induced by ornidazole and alpha-chlorohydrin.

The protein composition of epididymal fluid and sperm extracts of rats treated with the nitroimidazole compound ornidazole was investigated by two-dimensional gel electrophoresis. Epididymal luminal fluid from the corpus and cauda regions of male animals rendered infertile by ornidazole treatment contained a prominent protein (contraception-associated protein 1, CAP1) with a molecular mass of approximately 25 kDa and an isoelectric point (pI) of 5.8; it was not found in fluids, but was present in sperm, from fertile vehicle-fed rats. Infrared matrix-assisted laser desorption/ionization mass spectrometry indicated that the molecular mass of CAP1 was 20420+/-120 daltons. Analysis of 17 amino acids demonstrated 49% homology to a diuretic hormone from an insect (Acheta domesticus). Densitometric quantitation of CAP1 on silver-stained gels indicated its presence in greater amounts in cauda than in corpus fluid from treated animals, whereas fluid from the rete testis lacked CAP1. In vitro incubations of tissue from the caput, corpus, and cauda epididymidal regions with [35S]methionine gave no hint that CAP1 was a secretion product of the epididymal epithelium. The absence of CAP1 from luminal fluid obtained from the sperm-depleted corpus epididymidis of efferent duct-ligated ornidazole-fed rats suggested a spermatozoal origin. CAP1 was present in spermatozoa from the caput epididymidis but not from the rete testis in control animals. Less CAP1 was present in detergent extracts of cauda sperm from ornidazole-treated rats than in sperm from control animals, suggesting a contraceptive-related displacement of protein from sperm to fluid. The association of ornidazole- and alpha-chlorohydrin-induced infertility with the presence of CAP1 in epididymal fluid, probably originating from spermatozoa, suggests a critical role for this protein in fertilization.

Animals↗