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T G Cooper

Publications and source records attributed to T G Cooper.

318 records · Page 18Linked to original sources
PubMedDate not supplied

Regional variation in macrophage antigen expression by murine epididymal basal cells and their regulation by testicular factors.

Factors controlling the appearance in the epididymis of basal cells and their expression of macrophage antigens were examined by ligating the efferent ducts to prevent the entry of spermatozoa in adult and juvenile mice. Fixation and antigen retrieval techniques were developed to preserve tissue morphology and expression of two macrophage antigens in paraffin-embedded epididymal tissue. A combination of periodate-lysine-phosphate fixation, low-temperature embedding and enzyme predigestion of sections permitted immunohistochemical detection of the mature macrophage antigen Mac-1, whereas the panmacrophage marker F4/80 required fixation in neutral-buffered formalin. Epididymal basal cells were immunostained for F4/80 and quantified with avidin-biotin-peroxidase. In the adult mouse, the total number of basal cells per millimeter length of tubule cross section perimeter and the percentage expressing the F4/80-antigen were significantly higher in the initial segment and caput region than in all other epididymal regions. In the initial segment, immunostained basal cells surrounded the tubule in a network, and some extended towards the lumen. Ligation of the efferent ducts to prevent inflow of testicular secretions significantly reduced the number of basal cells per cross section in the initial segment of the adult and juvenile; the percentage of basal cells expressing macrophage antigens in the initial segment and the caput epididymidis was also reduced. Since basal cells still appeared in the ligated postpubertal epididymis, it is concluded that testicular exocrine secretions entering the epididymal lumen around puberty are not the major influence on basal cell appearance in the murine epididymis, but they may modulate their expression of macrophage antigens.

Aging↗
PubMedDate not supplied

Maturation of epididymal spermatozoa in the nondomesticated guinea pigs Cavia aperea and Galea musteloides.

The physiological changes occurring in spermatozoa in the male reproductive tract of 2 nondomesticated species of South American guinea pigs with different mating systems were studied. Cavia aperea, the wild ancestor of the domesticated guinea pig, has a polygynous mating system, whereas Galea musteloides exhibits promiscuous mating behavior. The epididymis of both species resembled that of the domesticated guinea pig, with a swathe of tubule convolutions (linking the 2 major parts of the organ) that was of smaller size in Cavia but not Galea. Higher relative epididymal weight was demonstrated in the promiscuous species. During their journey through the epididymis, spermatozoa from Galea developed their potential for motility expression more proximally than did those of Cavia, but motility developed into forward progression in the same region in both species. The maximal velocities exhibited by mature Cavia sperm in vitro were greater than those of Galea. Spermatozoa from Cavia were twice the length of those from Galea, they had larger heads, and the acrosomes of single sperm were more sensitive to disruption during morphological preparation. Only in Cavia did agglutination of sperm into rouleaux occur, after the potential for motility had been developed. Migration of the cytoplasmic droplet along the midpiece occurred in the same regions in both species and before agglutination in Cavia. It is suggested that the male's reproductive strategy (polygyny vs promiscuity) dictates the size of the testis and epididymis, whereas the female's reproductive physiology (induced ovulation vs cyclicity) influences the posttesticular development of sperm morphology and motility in the epididymis.

Animals↗
PubMedDate not supplied

Expression and cellular localization of contraception-associated protein.

Treatment of male rats with ornidazole results in reversible infertility, which is associated with the detection of the contraception-associated protein 1 (CAP1) in epididymal fluid. The protein, which is present in sperm but not detectable in epididymal fluid of fertile rats, seems to be shed from sperm during ornidazole administration. Cloning and characterization of the gene revealed a high degree of similarity between CAP1 and DJ-1 (Wagenfeld et al, 1998b) a protein that was recently found in humans and which has been classified as a novel oncogene. Reverse transcription of total ribonucleic acid (RNA) from various species indicated that a gene similar to CAP1 was also expressed in the testes of hamsters, mice, cynomolgus monkeys, and humans. Detection of RNA expression in rats at the cellular level by in situ hybridization revealed a stage-specific CAP1 expression in the cytoplasm of pachytene spermatocytes (stages IX-XIII), secondary spermatocytes (stage XIV), and round spermatids (stages I-VII). Immunolocalization of CAP1 in rat testis showed a strong staining of elongating spermatids (stages VI-VIII), indicating a translational delay of CAP1 expression. The location of CAP1 on sperm depended on the method of fixation used, with CAP1 being exhibited on the equatorial segment of the sperm head and cytoplasmic droplets. Flow cytometric analysis of sperm from ornidazole-fed rats revealed a significant decline (of 22%-24%) in the amount of sperm surface CAP1 compared with controls, which is associated with an altered location on the sperm head. These observations support a putative role of the protein in the fertilization process.

Animals↗
PubMedDate not supplied

High-b-value diffusion-weighted MR imaging of adult brain: image contrast and apparent diffusion coefficient map features.

BACKGROUND AND PURPOSE: Recent improvements in MR gradient technology allow significant increases in diffusion weighting without prohibitive signal-to-noise degradation. The purpose of our investigation was to establish normative references for the signal intensity characteristics and apparent diffusion coefficient values of the adult brain at high b values. METHODS: Fifty adults underwent diffusion-weighted single-shot spin-echo echo-planar MR imaging. Isotropic diffusion-weighted images were obtained with b values of 0, 1,000, 2,000, 2,500, 3,000, and 3,500 s/mm2. Qualitative assessments were made in multiple regions of interest in gray and white matter. Three apparent diffusion coefficient maps were generated for each of six patients with a 2-point technique at a b value of 0 and at b values of 1,000, 2,000, and 3,000 s/mm2. RESULTS: Increasing b values result in a progressive decrease in the gray to white matter signal intensity ratio. Isointensity between gray and white matter results at b values between 1,000 and 2,000 s/mm2. At b values greater than 2,000, the gray-white pattern reverses relative to the usual b value of 1,000. Apparent diffusion coefficient values were shown to decrease with increasing b values. CONCLUSION: Attention to the reversal of gray-white contrast and the dependence of apparent diffusion coefficient on the b value are important in avoiding erroneous assignment of pathologic abnormalities to normal regions. This study provides the normative data for future diffusion investigations performed at high b values.

Adolescent↗
PubMedDate not supplied

Susceptibility of glycolytic enzyme activity and motility of spermatozoa from rat, mouse, and human to inhibition by proven and putative chlorinated antifertility compounds in vitro.

Nonhormonal contraceptives that act by blocking energy metabolism within sperm have the advantage over spermatogenic inhibitors by their fast onset of infertility and their almost immediate restoration of fertility after withdrawal of the contraceptive agent. This study was done to test new chlorinated compounds for their contraceptive potency on rodent and human sperm in vitro. Cells were incubated in a medium containing glucose as the sole energy source with 1-chloro-3-hydroxypropanone (CHOP) and 1,6-dichloro-1,6-dideoxy-D-fructose (DCDF), chlorinated analogues of glycolytic substrates, as well as racemic (R,S)-alpha-chlorohydrin (ACH). After incubation, enzymatic activity and kinematic parameters were estimated. A dose-dependent inhibition of the glycolytic enzyme, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), of rat and mouse distal cauda epididymidal and human ejaculated sperm by ACH, CHOP, and DCDF was demonstrated. Triosephosphate isomerase (TPI) was inhibited by ACH, but not by CHOP and DCDF, irrespective of species. All compounds inhibited sperm motility and kinematic parameters with increasing concentration. The results confirm that inhibition of glycolytic enzymes of sperm, including those of human, can be effectively brought about by a variety of chloro-compounds that can be converted to (S)-3-chlorolactaldehyde, the stereospecific chloro-derivative of the enzyme's natural substrate, (R)-glyceraldehyde 3-phosphate, and could be developed into contraceptive agents for men.

Acetone↗
PubMedDate not supplied

Increase in seminal transferrin following antiandrogen treatment.

Seminal plasma transferrin was determined by radioimmunoassay in normal and infertile men under basal conditions and after manipulations of FSH and testosterone known to stimulate Sertoli cell activity and transferrin secretion in vitro. Normal volunteers were given the antiandrogens cyproterone acetate or flutamide, or a combination of 19-nortestosterone together with medroxyprogesterone. Severely oligozoospermic patients were treated with pulsatile GnRH to decrease elevated FSH levels. No close correlation between seminal transferrin and any of the serum hormones could be detected under basal conditions. However, antiandrogen treatment increased transferrin in seminal plasma, although from the in vitro studies a decrease or no effect would have been expected. No effect on seminal transferrin was detected in the patients receiving GnRH treatment. Since seminal transferring after hormonal treatment did not parallel transferrin secretion by Sertoli cells under hormonal stimulation in vitro, its role as a diagnostic marker for Sertoli cell function remains questionable.

Adult↗
PubMedDate not supplied

Rapid MR imaging of the liver: comparison of twelve techniques for single breath-hold whole volume acquisition.

Twelve magnetic resonance imaging pulse sequences for single breath-hold whole volume acquisition of the liver were evaluated on volunteers. Liver and spleen contrast to noise ratio (C/N), overall image quality, and grade of artifacts were compared. The 12 sequences included T2-weighted fast spin echo (FSE) with or without fat suppression (FS), fast multiplanar spoiled gradient recalled imaging (FMPSPGR), fast gradient recalled imaging without preparation pulses (FGR), FGR with inversion recovery preparation pulse nulling the liver or fat (IR-FGR-L and IR-FGR-F), FGR with driven equilibrium preparation pulse (DE-FGR), single shot moderately or heavily T2-weighted spin echo echo planar imaging (SE-EPI-mT2 and SE-EPI-hT2), multi-shot moderately T2-weighted spin echo echo planar imaging (multi-shot SE-EPI-mT2), inversion recovery EPI, and gradient echo EPI. In the quantitative analysis, FSE + FS showed a significantly higher C/N ratio than the others (p < 0.05). In the qualitative evaluation, DE-prepFGR, and single and multi-shot SE-EPI-mT2 had good results, as did FSE and FSE + FS. Further studies should be conducted to determine whether or not these breath-hold sequences can obviate current conventional non-breath-hold sequences.

Adipose Tissue↗
PubMedDate not supplied

Flow velocity and volume measurement of superior and inferior mesenteric artery with cine phase contrast magnetic resonance imaging.

The flow velocity and volume of the superior and inferior mesenteric arteries (SMA, IMA) were measured with cine phase contrast magnetic resonance (MR) imaging in five healthy volunteers. Each volunteer was first measured in a fasting state, and then one, two, and three hours after a meal. The average SMA flow volume of the volunteers was 230.3 +/- 46.8 ml/min (mean +/- standard error) during the fasting state, and 714.7 +/- 207.7 ml/min, 339.2 +/- 85.7 ml/min, and 263.8 +/- 21.0 ml/min, respectively, at one, two, and three hours postmeal. The increase at one hour postmeal was statistically significant (p < 0.05). The corresponding flow measurements in the IMA were 63.1 +/- 11.2 ml/min, 67.6 +/- 11.2 ml/min, 57.9 +/- 8.6 ml/min, and 53.2 +/- 6.8 ml/min. These values do not represent a statistically significant flow volume change in the IMA. In all volunteers, the SMA volumetric flow increased the most one hour after the food challenge (72-400% relative to baseline). Diastolic velocity in the SMA increased significantly one hour postmeal, but systolic velocity did not change significantly. The IMA did not demonstrate a significant change in either systolic or diastolic velocity. The difference between the SMA and IMA in the way of reacting against the food challenge is thought to represent the difference between the requirements of small and large intestine for blood supply after the food challenge. These data demonstrate the possibility of this modality for the assessment of conditions such as chronic mesenteric ischemia.

Adult↗
PubMedDate not supplied

Maturation of monkey spermatozoa in the epididymis with respect to their ability to undergo the acrosome reaction.

Spermatozoa obtained along the length of the epididymides from five macaque monkeys (Macaca fascicularis) were examined for their ability to undergo the acrosome reaction under basal conditions and when stimulated with the calcium ionophore A23187. Under basal conditions (2.5 hours incubation in potentially capacitating medium) few epididymal sperm cells displayed the loss of acrosome as judged by staining with peanut agglutinin lectin that binds to the outer acrosomal membrane, regardless of the epididymal region from which they were retrieved. By contrast, there was a marked difference in response to short (0.5 hour) incubation with the calcium ionophore A23187, which induced acrosome reactions in the majority of caudal sperm: caput sperm failed to respond at all and corpus sperm were about 50% as responsive as caudal spermatozoa. There is thus a development of the ability to respond to the ionophore upon maturation. Ejaculated spermatozoa from the same monkeys displayed a higher rate of basal acrosomal loss but a slightly lower stimulated response than mature epididymal spermatozoa. With these maturational aspects, monkey epididymal sperm can serve as a model for the study of human sperm maturation.

Acrosome↗
PubMedDate not supplied

Antifertility potential of ornidazole analogues in rats.

In order to determine which part of the ornidazole molecule [1-(3-chloro-2-hydroxy)propyl-2-methyl-5-nitroimidazole] is responsible for its antifertility action, structural analogues were fed to male rats of proven fertility at doses equivalent to the antifertility dose of ornidazole (1.82 mmol/kg/day). The fertility of the males was tested, before oral gavage (control mating) and after 10 and 14 days of feeding, by counting the number of fetuses and corpora lutea present in females 12 days after mating. The day after the last mating, the kinematic parameters of sperm from the cauda epididymidis were assessed objectively with a Hamilton-Thorne motility analyzer. Analogues bearing the 2-nitro and 5-methyl groups on the imidazole ring were inactive if the (chlorohydroxy)propyl group were substituted by proton or methyl, hydroxyethyl, chloroethyl, or (sulfonylethyl)ethyl groups, indicating that the three-carbon side chain of ornidazole was necessary for the antifertility action. Only ornidazole and its acetate were effective antifertility agents, but a compound bearing the (chlorohydroxy)propyl side chain attached to a nitrogen atom of a heterocyclic phthalimide produced a partial but temporary reduction in fertility. Similarities of the action of ornidazole with the male antifertility agent, alpha-chlorohydrin [3-chloro-1,2-propanediol], are discussed.

Animals↗
PubMedDate not supplied

A flow cytometric technique using peanut agglutinin for evaluating acrosomal loss from human spermatozoa.

Flow cytometric methods for the quantification of acrosome-reacted ejaculated human spermatozoa are described in which fluorescence-labeled peanut agglutinin (Arachis hypogaea) binding to the outer acrosomal membrane is used after incubation with ethidium homodimer (EHD) as vital dye and membrane permeation using methanol. Fluorescein-labeled fucoidan (F-fucoidin) was shown to bind to sperm that were also stained by propidium iodide (PI) and EHD; therefore, the use of F-fucoidin as vital dye was incorporated into the study. F-fucoidin and EHD can withstand the acrosome-staining procedure, unlike PI, which is leached out during cell processing. During incubation of spermatozoa, nonviable cells, as indicated by PI or F-fucoidin staining, appear in parallel with acrosome-reacted cells regardless of whether they are induced by the calcium ionophore A23187. The window of time in which viable, acrosome-reacted sperm cells can be detected is narrow and could depend on the vital dye as well as the acrosomal marker used.

Acrosome Reaction↗