Biomedical subjects

F Hrudka

Publications and source records attributed to F Hrudka.

At least 19 recordsLinked to original sources

PubMed1996

Changes in circulating hormone concentrations, testes histology and testes ultrasonography during sexual maturation in beef bulls.

Nine groups of bull calves (n = 5 to 6 per group) were castrated every 5 wk from 5 to 45 wk of age, and the stages of spermatogenesis were identified histologically. Prior to castration, the testes of each calf were examined by ultrasonography, and the pixel intensities of the parenchyma were quantitated. Testis ultrasonograms were also recorded every 2 wk from 10 bull calves between 2 and 40 wk of age. Blood samples were collected at weekly intervals until castration. There was an early transient rise in circulating LH concentrations between 4 and 25 wk of age, while circulating FSH concentrations were high initially but decreased between 14 and 30 wk of age. Circulating testosterone concentrations increased gradually from 6 to 35 wk of age and then rapidly to 42 wk of age. There was a progressive increase in the more mature cell types during spermatogenesis as the animals aged, with the most dramatic changes occurring between 15 and 45 wk of age. Outer seminiferous tubule diameter increased between 10 and 45 wk of age, with the most rapid increase occurring from 30 wk of age. Inner tubule diameter increased between 30 and 35 wk of age. The echogenicity of the testes (as determined by ultrasonography) increased between 20 and 40 wk of age. From these data we conclude that testis echogenicity increased during the most active phase of growth of the seminiferous tubules as more mature germ cells were produced. Cessation of the early rise in gonadotrophin secretion immediately preceded this active phase of testicular development. Testosterone secretion rose markedly with the production of mature spermatozoa.

Journal Article↗

PubMed1993

Morphological evidence of cyclic changes observed in Leydig cells of a chimeric mouse.

Light and electron microscopy were employed in studying morphologic heterogeneity in Leydig cells (LC) in situ, as manifested in a chimeric mouse. This mouse was chosen to take advantage of increased LC concentration in territories of agametic tubules (Hrudka et al., 1989). Large number of LC's, side by side, gave better opportunity to compare their size, shape, organelle representation, surface specialization and mutual interaction. Because cell organelles and inclusions were distinctive, we were able to monitor their dynamics and changes in cell shape and size, as well as phenomena in the intercellular space. In spite of an apparent continuum, a series of definite forms or stages were identified, in the course of the study. After arranging these reproducible and predictable forms in a logical sequence, the following, tentative cycle of secretory activity of LC is proposed: 1) stage of transient or 'lean' cell, 2) stage of SER proliferation and cell hypertrophy, 3) stage of lipid deposition or 'fat' cell and 4) stage of regression.

Animals↗

PubMed1989

Co-existence of gametic and agametic seminiferous tubules in a chimeric mouse. A light- and electron-microscopic study.

Six chimeras, including 4 phenotypic males and 2 females, were produced by aggregation of F1 (C57BL x BALB/c) and Swiss white embryos. All were fertile, except 1 male, whose deviation in testicular structure prompted this light- and electron-microscopic study. This chimera had a well-developed sperm-conducting system, sperm in the epididymis and active accessory sex glands. The testes displayed typical parenchymal and stromal components with the important exception of co-existence of gametic and agametic seminiferous tubules. These tubules were organized in territories of quasi-lobular configurations which appeared to open separately into rete testis. The former corresponded to normally developed and active seminiferous tubules, while the latter were solid testicular cords devoid of any germ cells and embedded in solid masses of interstitial (Leydig) cells. Special mitochondrial transformations were identified in sustentacular (Sertoli) cells of both types of tubules, in maturing spermatids and sperm. These and other submicroscopic sperm defects might be the cause of infertility.

Animals↗

PubMed1988

Nodulous corpuscles and mitochondrial inclusions in Sertoli cells of deer hybrids.

Unusual transformations of endoplasmic reticulum and mitochondria were identified in the Sertoli cells of deer hybrids. A portion of the mitochondrial population was converted from the common, flexible mitochondrial form into stiff rods, with an increased volume of the matrix and relative paucity of cristae. The matrix displayed arrays of tubuloid elements or percursors at various stages of assembly. The second and more conspicuous adaptation concerned the agranular endoplasmic reticulum, which frequently transformed into oval or elongate, often interconnected bodies. These bodies consisted of a dozen or more concentrically arranged fenestrated cisternae and a variable amount of glycogen in between. An integral and distinctive feature of the cisternous bodies was nodes, together constituting the so-called nodulous corpuscles (NC). The nodes appeared as a dense meshwork or lattice, which has the potential to generate a new set of cisternae and NC that interconnect into a chain or tridimensional complex. The course of NC evolution from precursors to mature complexes is proposed. Both organelle adaptations occurred independently and in only Sertoli cells. They are believed to be a product of hybridization in deer.

Animals↗

PubMed1987

Cytochemical and ultracytochemical demonstration of cytochrome c oxidase in spermatozoa and dynamics of its changes accompanying ageing or induced by stress.

Cytochrome c oxidase (CcO) plays a key role in cellular respiration and energetic metabolism. The latter is a prerequisite for osmotic and synthetic function, motility and the maintenance of cell structure. The objective of this study was to develop and assess a facile microscopic technique that would demonstrate CcO activity insitu, both at the microscopic and sub-microscopic levels. The cytochemical technique proposed is based on oxidation of 3,3'-diaminobenzidine (DAB) by the cytochrome c complex (including CcO), in a chain reaction in which the reagent is polymerized and deposited at the reaction sites. The deposit can be identified by its colour under the light microscope and by osmiophilia under the electron microscope. The reaction is restricted to mitochondria at the light microscope level, and to the outer face of the inner mitochondrial membrane at the ultrastructural level. The activity is inhibited promptly by greater than or equal to 0.5 mM KCN, a specific inhibitor of CcO, and by sodium azide or heat (70 degrees C/5 min). The technique was validated on a number of domestic and laboratory animals, using sperm that were ejaculated or epididymal in origin, cryopreserved or treated. The data obtained displayed activity profiles of individual cells, ejaculates or donors and emphasized differences among species. This technique depicts spontaneous CcO decline during ageing and changes induced by various physical or chemical treatments.

Aging↗

PubMed1984

Comparison of the effects of gossypol, estradiol-17 beta and testosterone compensation on male rat reproductive organs.

The effects of gossypol acetic acid (GAA) were compared with those induced by estradiol-17 beta (E2), testosterone, and a combination of these steroids. GAA was administered s.c. to adult rats at doses of 25 to 30 mg . kg BW . day for 30 days, while steroids in polydimethylsiloxane tubing of various lengths were implanted s.c. for 30 days or longer. GAA and E2 at the doses used had similar effects: they caused a graded atrophy of sex organs, discriminative degeneration of spermatogenic cells, impairment of Sertoli cells, decrease in serum testosterone, reduction in androgen receptor binding and retardation in body growth. Supplementing GAA and E2 treatments with 14-cm testosterone implants had a counteracting effect on organ weight losses: seminal vesicles recovered above, ventral prostate within and epididymides below control values, whereas the testes did not respond. The organs most refractory to supplementation therapy were those in which GAA and E2 were most effective in depressing androgen receptor binding. Aside from having similar antiandrogenic effects as E2 and other steroids, GAA induced a specific flagellar syndrome which testosterone therapy could not prevent, indicating that this action is hormonally independent.

Animals↗

PubMed1984

Sperm nucleomalacia in men with inflammatory bowel disease.

The extent and nature of seminal anomalies in colitic and ileitic patients were investigated using cytological, cytochemical, and electron microscopical methods. In addition to basic seminal variables, the gross and fine structure of spermatozoa were analyzed and the recorded data correlated with actual clinical conditions and therapeutic regimen of patients. Spermiograms revealed that the effect on the testicular function varied among patients, ranging from a subtle embarrassment of late spermiogenesis to a suppression of spermatogenesis as reflected in severe oligozoospermia. In several instances, excurrent ducts and accessory sex glands also were involved. The nuclear syndrome was an invariably observed phenomenon and consisted of increased pleomorphy, excessive vacuolation, postnuclear blebbing, malcondensation, and spontaneous decondensation of chromatin. The nuclear pleomorphy, malcondensation, and decondensation, apparently interrelated, constitute the characteristic condition, referred to as nucleomalacia. Other sperm defects seemed to be mere amplifications of deficiencies common in human semen. The correlation between the extent of intestinal lesions or severity of symptoms and the ratio of nuclear aberrations, demonstrated with acid-fast technique, was striking. No such relationship was found regarding the sulfasalazine treatment.

Acrosome↗

PubMed1984

Spermiophagy in vitro.

An in vitro procedure was designed to investigate whether macrophages discriminate between live and dead sperm and between sperm of different donors. In this procedure 1 million murine peritoneal macrophages were allowed to attach to a cover glass, and the resulting monolayer was overlaid with the same number of sperm cells. The spermiophagic index (SPI) was determined by counting sperm heads phagocytized in 100 macrophages after a given exposure time under standard conditions of incubation. The SPI was proportional to the exposure time, and the curve of dynamics leveled off after 5 h of incubation. This study has shown that sperm cells in an in vitro system are avidly phagocytized by macrophages regardless of their origin, live or dead, provided their plasmalemma is preserved. Preliminary observations in female mice did not support the hypothesis that SPI was inversely proportional to the egg fertilization rate.

Animals↗

PubMed1982

Segmental aplasia of the mitochondrial sheath and sequelae induced by gossypol in rat spermatozoa.

The effect of gossypol upon organelles of rat sperm was investigated by light and electron microscopy. The drug was administered s.c. for 2 to 30 days at 20 mg/kg BW/day. Sperm from the testis, caput, corpus, and cauda epididymis were examined at regular intervals, during and after treatment, for periods extending up to 70 days. The drug induced a specific effect in the sperm tail. It consisted of segmental aplasia of the mitochondrial sheath observed in high incidence in testicular and epididymal sperm. This primary lesion, in the authors' view, predisposed a development of secondary lesions as sperm advanced along the epididymis. Secondary lesions included bulging, dislocating, fraying, or breaking of axial fibers, bending or breaking of the tail, and decapitation. A minimum of 3 days of treatment was necessary to produce an effect above control values, while 9 days or longer induced lesions in almost all sperm. Motility ceased with 30 days of treatment. Fertilizing capacity was inversely related to the increase and decline of lesions.

Animals↗

PubMed1980