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Rex A Hess

Publications and source records attributed to Rex A Hess.

24 records · Page 2Linked to original sources
PubMed2002

Microtubules of the mouse testis exhibit differential sensitivity to the microtubule disruptors Carbendazim and colchicine.

The testicular toxicant benomyl and its metabolite, carbendazim cause reproductive damage to the rat, an early sign of which is sloughing of germ cells with associated Sertoli cell fragments. However, the sensitivity of other mammalian species to these benzimidazole compounds is not clear. In this study, the effects of carbendazim and colchicine, a known microtubule disruptor, on the mouse seminiferous epithelium were characterized, and the amount of carbendazim reaching the mouse testis was measured. Testes were assessed for histological effects 3 h and 6 h after administration of carbendazim (2000 mg/kg, ip), and 6 h after intratesticular administration of either a low or high dose (5.3 or 117.6 micro g/g testis) of colchicine. Carbendazim caused no signs of histological damage to the mouse testis, and the microtubule cytoskeleton was intact and identical to controls based on immunostaining with tyrosinated alpha tubulin and beta tubulin antibodies. Similarly, the seminiferous epithelium of mouse testis was undamaged and the microtubule cytoskeleton was intact after a low dose of colchicine, while a comparable dose of colchicine injected into rat testis caused marked toxicity. However, mouse testes did show microtubule disruption and severe germ cell sloughing after administration of a high dose of colchicine. The amount of carbendazim measured in mouse testis was 375 nmol/g testis, which is higher than the value measured in rat testis after a toxic dose of carbendazim. Therefore, carbendazim reaches the mouse testis at or above levels measured in the rat, yet the mouse is apparently insensitive to this microtubule disrupting agent.

Animals↗
PubMed2002

Differential expression of estrogen receptors alpha and beta in the reproductive tracts of adult male dogs and cats.

Expression of estrogen receptors (ERs) in the reproductive tracts of adult male dogs and cats has not been reported. In the present study, ERalpha and ERbeta were localized by immunohistochemistry using ER-specific antibodies. ERalpha was found in interstitial cells and peritubular myoid cells in the dog testis, but only in interstitial cells of the cat. In rete testis of the dog, epithelial cells were positive for ERalpha staining, but in the cat, rete testis epithelium was only weakly positive. In efferent ductules of the dog, both ciliated and nonciliated cells stained intensely positive. In the cat, ciliated epithelial cells were less stained than nonciliated epithelial cells. Epithelial cells in dog epididymis and vas deferens were negative for ERalpha. In the cat, except for the initial region of caput epididymis, ERalpha staining was positive in the epithelial cells of epididymis and vas deferens. Multiple cell types of dog and cat testes stained positive for ERbeta. In rete testis and efferent ductules, epithelial cells were weakly positive for ERbeta. Most epithelial cells of the epididymis and vas deferens exhibited a strong positive staining in both species. In addition, double staining was used to demonstrate colocalization of both ERalpha and ERbeta in efferent ductules of both species. The specificity of antibodies was demonstrated by Western blot analysis. This study reveals a differential localization of ERalpha and ERbeta in male dog and cat reproductive tracts, demonstrating more intensive expression of ERbeta than ERalpha. However, as in other species, the efferent ductules remained the region of highest concentration of ERalpha.

Animals↗
PubMed2002

ER function in the adult male rat: short- and long-term effects of the antiestrogen ICI 182,780 on the testis and efferent ductules, without changes in testosterone.

Male rats, 30 d old, were treated with the antiestrogen ICI 182,780 (3-150 d) to determine sequences of events leading to testicular atrophy and infertility. Plasma testosterone and LH concentrations were unchanged. ICI 182,780 induced dilation of efferent ductules as early as 3 d post treatment, and the dilation increased over time, resulting in an overall increase of 200% in tubule diameter. A gradual reduction in height of the ductule epithelium was observed; however, the microvilli height increased up to d 73 but subsequently decreased. A transient increase in lysosomes in nonciliated cells was seen from d 15 to d 100. Testicular weight increased by d 45 and seminiferous tubules were dilated by d 52. These effects on testes persisted until d 100, but on d 150 the weight decreased and severe atrophy was observed. These testicular effects were probably owing to accumulation of fluid following inhibition of reabsorption in the efferent ductules, similar to the ER-alpha knockout mouse. In agreement with this conclusion, there was a decrease in Na+-H+ exchanger-3 mRNA and protein, which is consistent with previous studies showing that ER is required for expression of Na+-H+ exchanger-3 and ultimately fluid reabsorption in the efferent ductules.

Acid Phosphatase↗
PubMedDate not supplied

Immunofluorescence reveals ubiquitination of retained distal cytoplasmic droplets on ejaculated porcine spermatozoa.

The purpose of the present study was twofold: 1) to determine if antibodies raised against ubiquitin would recognize antigens associated with the porcine cytoplasmic droplet (CD), and 2) to determine if the same antibody would identify ubiquitinated substrates on the surface of morphologically abnormal boar spermatozoa. Permeabilization with the detergent Triton X-100 (0.05%) showed virtually all CDs to be ubiquitin positive. Distal droplets (DDs) retained in situ on boar spermatozoa were readily labeled following Triton permeabilization, whereas DDs present on nonpermeabilized cells were not. Negative control preparations lacked the ubiquitin staining on the DD. The use of microtubes for fixation and incubation provided clearer images as well as better sperm cell distribution and density than an initial slide-mounted technique. Immunoblotting indicated that larger amounts of ubiquitinated proteins were present in extracts from sperm cells from an ejaculate with an abnormally high percentage of retained DDs (52% DDs) compared to a morphologically normal sample (6% DDs). The primary antibody recognized both mono-ubiquitin of bovine origin (8.5 kd) and human ubiquitin conjugate (35 kd), as demonstrated by Western blot. Preabsorption of the anti-ubiquitin antibody with purified bovine ubiquitin was successful in preventing diaminobenzidine staining of sperm extract from the high DD ejaculate. The presence of antigens recognized by anti-ubiquitin antibodies in the boar sperm CD, coupled with the possibility that superfluous ubiquitin species are detrimental to embryonic development by targeting critical paternally contributed zygotic organelles, raises concerns that retained DDs may be more detrimental to fertility than previously suspected.

Animals↗
PubMedDate not supplied

Localization of androgen and estrogen receptors in adult male mouse reproductive tract.

There is considerable variation, both within and between species, in reports of nuclear steroid receptor localizations in the male reproductive tract. In this study, androgen receptor (AR) and estrogen receptors ERalpha and ERbeta were visualized by immunohistochemistry in adult male mice reproductive tracts, including testes, efferent ductules; initial segment, caput, corpus, and cauda epididymides; and vas deferens. Antibody specificity was demonstrated by Western blot and antibody competition. In testis, AR was expressed in Leydig cells, Sertoli cells, and most peritubular cells, but not in germ cells; Sertoli cells showed more intense staining in stages VI-VII; ERalpha was present in Leydig and some peritubular cells; ERbeta was in Leydig, some peritubular, all Sertoli and germ cells except in spermatids and meiotic spermatocytes. In efferent ductules, AR was strongly expressed in ciliated and nonciliated epithelial cells and in stromal cells; ERalpha was strongly expressed in ciliated and nonciliated epithelial cells; stromal cells were negative; and ERbeta was strongly expressed in ciliated and nonciliated epithelial cells and also in stromal cells. In epididymis, AR was strongly expressed in all epithelial cells (not in intraepithelial lymphocytes); ERalpha was strongly expressed in apical, narrow, and some basal cells of the initial segment, and in caput, principal cells of the caput, clear cells of the distal caput through cauda; stromal cells were negative in the initial segment, but more stromal cells were stained from caput to cauda; ERbeta was strongly expressed in most of epithelial cells of the epididymis, but stromal cells were inconsistently stained. In vas deferens, AR was weakly expressed or absent in principal cells but moderately stained in basal cells, smooth muscle cells of stroma were stained intensely, ERalpha was absent in epithelial cells but present in a subepithelial smooth muscle layer, and ERbeta was strongly expressed in all epithelial cells and most stromal cells. This study demonstrates that the reproductive tracts of male mice differ considerably from those of rats in expression of ARs and ERs and that caution is needed when extrapolating nuclear steroid receptor data across mammalian species.

Animals↗