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Biomedical subjects

M S Bornman

Publications and source records attributed to M S Bornman.

At least 19 recordsLinked to original sources
PubMed2006

Stage-related increase in the proportion of apoptotic germ cells and altered frequencies of stages in the spermatogenic cycle following gestational, lactational, and direct exposure of male rats to p-nonylphenol.

The cumulative effects of environmental toxicants, for example, the alkylphenol, para-nonylphenol (p-NP) are of concern. Our previous study showed that p-NP reduced several testicular morphometric parameters, including sperm counts. The present study reexamined material collected in that study to determine the mechanistic basis of p-NP action on spermatogenic development in the offspring. Seven-day pregnant Sprague-Dawley rats were treated with vehicle or 100 or 250 mg/kg p-NP through gestation, lactation and afterward directly to all male offspring until 10 weeks of age. Both doses of p-NP significantly (P < 0.02) increased the number of germ cells with in situ end-labeled fragmented DNA (TUNEL positive) by 1.9-fold and 1.7-fold, respectively, and specifically in stages XII-XIV and I-III. TUNEL-labeling was, however, selective, and excluded labeling of basal cells with apoptotic morphology. Cleaved caspase-3 immunohistochemistry strongly labeled basal cells (spermatogonia and early spermatocytes) with condensed marginated chromatin but not degenerate germ cells lacking definitive nuclear material found throughout the epithelium. Only the caspase index (ratio of number of caspase positive to number of degenerate cells) of the 100-mg/kg p-NP group was significantly (p < 0.05) threefold greater than controls. Whereas both doses and either 250 or 100 mg/kg treatment alone significantly (p < 0.002) reduced the frequencies (duration) of stages I-III, VII-VIII, and late VIII-IX (spermiating and recently spermiated tubules), respectively, both doses significantly (p < 0.002) increased the frequencies of stages IV-VI and all stages containing late-stage spermatocytes (XII-XIII) and meiotic cell divisions (XIV). Thus, p-NP, an environmentally persistent xenoestrogen, insidiously alters the spermatogenic cycle and spermatogenic process in male offspring.

Animals↗
PubMed2006

Ultrastructural effects of low dosage endocrine disrupter chemicals on neural cells of the chicken embryo model.

Previous research suggests that endocrine disrupters (EDCs) like nonylphenol cause apoptosis (both via the intrinsic and extrinsic pathway) and that ROS generation and Ca (2+) play a fundamental role in the process. We have investigated morphological changes induced by 17beta-estradiol, nonylphenol, 17alpha-ethynylestradiol and diethylstilbestrol on the IN OVO neural chick embryo model by using transmission and scanning electron microscopy (TEM and SEM). We found that estrogenic substances such as nonylphenol, diethylstilbestrol (DES) and 17alpha-ethynylestradiol, as well as 17beta-estradiol cause ultrastructural changes to developing neurons, resulting in damage to the plasma, mitochondrial as well as nuclear membranes. Furthermore, both apoptotic blebbing and necrotic (or oncotic) budding was seen in TEM and SEM micrographs. SEM shows that nonylphenol-exposed neurons have irregular cell surfaces with pseudopodia, cell shrinkage and breakages in the plasma membrane--typical of apoptosis. TEM indicated that plasma membranes and double nuclear membranes have structural changes, with apoptotic bodies (blebbing) and disrupted mitochondrial membranes. In 17alpha-ethynylestradiol-exposed neurons, disruption of the plasma membrane with cell swelling and vacuolization was present. No apoptotic bodies or budding were noted here. 17beta-Estradiol induced openings in the plasma membrane, while DES-exposed neurons did not show any morphological changes. Therefore we conclude that EDC damage is morphologically visible and the damage is recognized as apoptosis and oncosis. Estrogenic substances may hence modify hormonal actions thereby leaving the developing nervous system more susceptible to damaging events.

Animals↗
PubMed2005

The neurotoxic effects of prenatal cardiac glycoside exposure: a hypothesis.

Cardiac glycosides (CGs) are beneficial in treating cardiac conditions; depending on time and dosage, they can also be toxic as they regularly cross the blood brain barrier and the placenta and may affect the unborn baby. This paper therefore focuses on the effects of CGs administered to the mother on normal cellular physiology of the foetus with specific reference to neural tissue. CGs act by binding to the Na+/K+-ATPase and decrease or inhibit Na+-K+ pump activity. In the foetus, CGs may disrupt ion homeostasis. An over-dosage of CGs or when it is taken during pregnancy, can also affect the neuro-energy levels of brain tissue in particular. We conclude and hypothesize that CGs in this case will not only cause severe alterations in neuronal function due to disruption of membrane activity, but also in glutamate clearance, affecting neurotransmission in general. Furthermore, elevated cytosolic Ca2+ will lead to permeabilization of the mitochondrial membranes, resulting ultimately in mitochondrial dysfunction. This will result in neurotoxicity--ensuing in neural cell damage or death, and we propose the mechanism to be due to neuro-necrapoptosis.

Animals↗
PubMed2005

Calcium-mediated aponecrosis plays a central role in the pathogenesis of estrogenic chemical-induced neurotoxicity.

Estrogen is traditionally associated with females but is also present in males, and influences aspects of brain chemistry and brain morphology in males, females and also during prenatal development. Humans as well as animals are additionally exposed to environmental products that mimic estrogen activity, also known as endocrine disrupters (EDCs). This hypothesis article investigates the role of estrogen (and also EDCs) in the brain and how it influences the Ca2+ pathway. Ca2+ and its movement in and out of the cell is an extremely important ion controlling normal cell physiology. Any dysfunction in the movement from outside to inside the cell or between organelles may have fundamentally negative effects and the disturbance may even lead to apoptosis and/or necrosis. Therefore we consider whether estrogen and EDCs may alter the Ca2+ physiology and whether these changes may be one of the main causes of interference in physiology that is seen when humans and animals are exposed to EDCs. We come to the conclusion that on a molecular level Ca2+ and Ca2+ fluxes ([Ca2+]i, endocrine disrupting chemicals, redox modulation, mitochondria and cytochrome c followed by apoptosis, necrosis or most likely aponecrosis may contribute to chemical-mediated developmental toxicity. Similarly, we hypothesize that calcium-mediated aponecrosis do not only play a central role in the pathophysiology of estrogenic chemical-induced neurotoxicity, but can contribute to chemical-mediated developmental toxicity in general, thereby affecting almost all cells and organs of the living organism.

Animals↗
PubMed2004

Histological evidence of intersex in feral sharptooth catfish (Clarias gariepinus) from an estrogen-polluted water source in Gauteng, South Africa.

This is the first histological evidence of intersex in a fish species inhabiting a South African water source. One hundred catfish (Clarias gariepinus) were collected randomly from the Marais Dam (MD) and the Rietvlei Dam (RVD) in the Rietvlei Nature Reserve (RNR), South Africa. These dams drain water from a stream that receives effluent from industrial sites, agricultural activities, informal settlements, and municipal treatment plants. Each fish was evaluated macroscopically and had blood drawn, and its gonads were macroscopically and histologically examined to verify intersex potentially related to endocrine disruption. Gonadal histology of several fish showed primary oocytes scattered in testicular tissue, indicative of intersex. The results showed intersexuality in 20% of fish from both the dams. The GSI value for intersex fish was closer to male GSI values, suggesting that the sampled intersex fish were more likely to have occurred from the feminization of male catfish. Target chemical analyses showed that the water, sediment, and serum samples tested positive for p-nonylphenol (p-NP). The p-NP level in water and sediment at MD was 6360 and 4.0 microg/kg, respectively, whereas in sediment at RVD it was 113 microg/kg. Commonly found in the effluent from sewage treatment plants, p-NP in water and sediment indicates estrogenic water pollution, which might affect wildlife and humans dependent on these sources.

Animals↗
PubMed2001

Epididymal markers in rats exposed to the xenoestrogen p-nonylphenol: no biochemical effects at low dosages.

Harmful micro- and macroscopic effects of the environmental xenoestrogen p-nonylphenol (p-NP) on the male rat reproductive system have been previously reported. In our study, biochemical evidence of epididymal involvement was sought by determining epididymal marker values after exposure at levels below (5, 20 and 50 mg kg-1) and above (100, 250 and 400 mg kg-1) the "no observed adverse effect" level (NOAEL: 50 mg kg-1 day-1). Exposure to p-NL below the NOAEL did not affect biochemical marker values. At levels above the NOAEL, biochemical markers of epididymal function were affected by the exposure of adults, and by maternal exposure (gestational and lactational periods followed by oral exposure until sexual maturity). l-carnitine was unchanged at all levels of exposure. Exposure of adult males to levels above the NOAEL resulted in higher alpha-glucosidase, suggesting increased epididymal secretory activity. This could upset the balance between secretory and reabsorptive function, and could alter the biochemical composition of the epididymal luminal fluid surrounding spermatocytes during the maturation process. Maternal exposure at levels above the NOAEL resulted in higher tartrate-resistant acid phosphatase activity in the caput-corpus epididymidis, which could indicate an oestrogen-mimicking effect.

Acid Phosphatase↗
PubMed1999

The effect of p-nonylphenol, an environmental toxicant with oestrogenic properties, on fertility potential in adult male rats.

Infertility is a sad reality and it is now evident that several aspects of male reproductive health have changed for the worse over the past 30-50 years. para-nonylphenol (p-NP), an environmental toxicant with oestrogenic properties, was tested for its effect on male fertility potential. When adult male rats were exposed to 100 mg kg-1 p-NP the histological parameters of the seminiferous tubules were adversely affected. Although spermatogenesis was already established in these males at the time exposure commenced, p-NP still had an effect on the histology of the seminiferous tubules. Increasing the level to 250 mg kg-1 additionally resulted in a smaller weight gain and signs of epididymal toxicity, while 400 mg kg-1 also impaired testicular mass and sperm count. In the last two groups spermatogenesis was also affected in some animals. Because p-NP had an effect on established spermatogenesis in the rat, one could speculate that the same effects might also occur in humans. It would appear that p-NP had toxic effects on both the testis and epididymis and both structures might be important in impairing male fertility. Bio-accumulation may enhance the negative effects at even lower p-NP concentrations over longer exposure periods than reported here.

Animals↗
PubMed1999

The effect of p-nonylphenol on the fertility potential of male rats after gestational, lactational and direct exposure.

There is growing concern that abnormalities in male reproductive health are becoming more frequent. The most fundamental change has been the striking decline in sperm counts and semen quality. The effect of maternal exposure of rats to the oestrogenic environmental substance p-nonylphenol (p-NP) was determined in this study. Exposure to p-NP for the experimental period impaired general growth. The lower testicular mass indicated a direct toxic effect on the testis in animals exposed to p-NP during foetal life, the postnatal period and after weaning until termination at 10 weeks of age. The epididymal mass was also negatively affected by p-NP; this was supported by the decrease in the epididymal ratio. The total cauda epididymal sperm count was significantly lower in the 250 mg kg-1 p-NP dosage group compared to the control and 100 mg kg-1 p-NP groups. The overall lower sperm count with increased p-NP concentrations corresponded with the decreased testicular and epididymal masses. This emphasized the toxicity of p-NP on both testis and epididymis. Seminiferous tubule diameter, lumen diameter and seminiferous epithelium thickness were smaller in the exposed groups, even at the low dose level. These histological measurements further supported the finding of a low testicular mass. In spite of the measurements being smaller, p-NP had no effect on the stages of spermatogenesis except for one animal with disrupted spermatogenesis in some tubules, while others were normal.

Animals↗
PubMed1997

Semen quality and fertility of men employed in a South African lead acid battery plant.

Previous studies of the associations of measures of occupational lead exposure with measures of semen quality and infertility among male workers have produced conflicting results. The current study was undertaken to examine these associations among a population of workers with a broad range of measures of current and historical lead exposure. Ninety-seven lead-exposed workers from a South African lead acid battery facility provided semen samples that were analyzed for sperm density, sperm count, sperm motility, sperm morphology, and presence of antisperm antibodies. Questionnaire data were collected for reported histories of sub- or infertility. Current blood leads ranged from 28 to 93 micrograms/dl. Semen lead ranged from 1 to 87 micrograms/dl. Reasonably consistent and significant associations were found between an increased percentage of sperm with abnormal morphology and higher measures of current blood lead, cumulative blood lead, and duration of exposure. An increased percent of immotile sperm was associated only with zinc protoporphyrin (ZPP) among the lead exposure measures. There were no associations of sperm density or sperm count with any of the lead exposure measures. A weak association of increased percent of sperm with antisperm antibodies with increased semen lead was present. There were no consistent associations of measures of lead exposure with measures of fertility or procreativity. This study, while supporting the association of lead exposure with increased risk of abnormal sperm morphology seen in some previous studies, does not lend support to previously reported associations of sperm density or count or infertility with measures of lead exposure. However, the relatively high range of current blood leads, high prevalence of abnormalities in semen quality, and the lack of a control population, suggest that these negative findings should be interpreted with caution.

Cross-Sectional Studies↗
PubMed1994

Urine as an alternative to urethral swabs for the diagnosis of Chlamydia trachomatis in infertile males.

Swabbing the urethrae of men has been the traditional approach for collecting specimens for detection of Chlamydia trachomatis. Recently, however, urine testing using enzyme immunoassay has yielded promising results. A total of 105 patients attending the Andrology Clinic at Ga Rankuwa Hospital, Medunsa were included in the study. These patients were asymptomatic and had no urethral discharge. Three endo-urethral swabs and first-catch urine were collected from each patient. The urethral swabs were used for enzyme immunoassay (EIA) (IDEIA III), tissue culture and direct immunofluorescent antibody (DFA) test (IMAGEN) to detect C. trachomatis. In addition about 15-30 ml of first-catch urine, or urine collected at least 2h after the previous micturition, was collected for each patient for EIA testing. Fifteen (14.3%) of 105 patients were positive on urethral swab EIA, in comparison with the DFA test in which 14 (13.3%) were positive. Eight (7.8%) were positive in tissue culture. Urine EIA was positive in 17 (16.2%) patients, of whom five (4.8%) were positive in urine EIA only. All EIA positive urines were confirmed by DFA. We recommend that first-catch urine or urine collected at least 2h after the previous micturition in infertile males may be considered a suitable alternative to urethral swab for chlamydial diagnosis because it is noninvasive and nontraumatic.

Adult↗
PubMed1994

Biochemical analysis of tunica vaginalis fluid in patients with or without idiopathic hydroceles.

OBJECTIVE: To establish the differences, if any, between the biochemical composition of idiopathic hydrocele fluid and the fluid normally present in the tunica vaginalis. PATIENTS AND METHODS: Aspiration and sclerotherapy of 37 idiopathic hydroceles from patients who presented to this urology clinic were performed. The biochemical content of the fluid was compared with that of the tunica vaginalis fluid from a small group of controls (n = 8), taken from patients undergoing orchidectomy for carcinoma of the prostate. RESULTS: Differences in several measurements were recorded; in particular, there were significantly higher concentrations of calcium, albumin, total protein and creatine-kinase in the hydrocele group. The levels of potassium, aspartate transaminase, alanine transaminase and alkaline phosphatase were significantly lower in the hydrocele group. CONCLUSION: Whether these differences have a role in the causation of an idiopathic hydrocele is, at this stage, speculative. A similar study on a larger scale would probably be more conclusive.

Albumins↗
PubMed1992

Sexually transmitted diseases (STD) in infertile males attending the andrology clinic at Ga-Rankuwa Hospital.

Sexually transmitted diseases (STDs) affect the physiology of male/female reproduction. Chronic bacterial infection of semen is uncommon, but may be a cause of male infertility. Antibacterial treatment results in improvement in sperm quality, once the infection is eradicated. Little is known about how infection with Mycoplasma hominis affects semen quality, but treatment with antibiotics improves motility and decreases the percentage of coiled tails. Chlamydia trachomatis is not frequently isolated from the urethral cultures of normal men, but is a major cause of nongonococcal urethritis and epididymitis. Chlamydia is an important cause of epididymal and oviductal obstruction. Trichomonas vaginalis most frequently colonizes the vagina and cervix of women and the anterior urethra of the male sexual partners. The highest prevalence is in sexually active men and women and Trichomoniasis may well be the most common STD. Syphilis may be an important cofactor in facilitating transmission of the human immunodeficiency virus (HIV). A history of syphilis or a positive serologic test for syphilis is associated with HIV seropositivity in men. In South Africa, the seropositivity in pregnant black women ranges from 11-20%. Ga-Rankuwa Hospital is the referral center for 40 peripheral hospitals and over 4 million people. Since the inception of the Andrology Laboratory in June 1985, more than 5300 semen analyses have been performed on 2000 patients.

Africa↗