Testicular microlithiasis and neoplastic lesions in wild eland (Tragelaphus oryx): possible effects of exposure to environmental pollutants?

The purpose of the study was to compare wildlife in the proximity and away from the sources of known industrial pollution. Macroscopic, focal, gritty areas that appeared white were observed in the testes of all 24 South African eland (Tragelaphus oryx) culled in the Rietvlei Nature Reserve (RNR; n=17) between 2001 and 2003 and Suikerbosrand Nature Reserve (SNR; n=7) in 2004. Histopathological evaluation of testes showed multiple intratubular dystrophic calcifications, focal areas of sperm stasis and interstitial chronic cell infiltrates with fibrosis. Spermatogenesis was generally impaired; a few atypical germ cells were also encountered. Sertoli cell vacuolization and sloughing of the seminiferous epithelium were evident. Adenomatous changes of the rete testis, reflective of possible chronic estrogenic exposure, were found. In testes collected from three reference eland in 2007 from the Molopo Nature Reserve (MNR) in the Kalahari/Kgalagadi Desert, except for one focal area of sperm stasis and another with microcalcification, the seminiferous epithelium as well as collecting/rete tubules were normal. Analyses of fat tissue for environmental pollutants showed that 11 out of 17 RNR eland contained a detectable estrogenic chemical p-nonylphenol (mean+/-SD: 184.8+/-24.6 microg/kg fat); no organochlorine chemicals or polychlorinated biphenyls were detected. Of the 7 SNR eland, 5 had detectable octylphenol residues (50.2+/-30.9 microg/kg fat), 3 had detectable p-nonylphenol (137.8+/-77.9 microg/kg fat), 3 had o-p'-DDT (114.9+/-31.1 microg/kg fat), 3 had p-p'-DDT (127.3+/-49.9 microg/kg(79.5+/-30.4 microg/kg fat) and 5 contained o-p'-DDE (27.7+/-9.9 microg/kg fat). One eland from the MNR contained one 70.6 microg o-p'-DDT/kg fat and another p-p'-DDE 61.3 microg/kg fat. Therefore, in eland with testicular abnormalities, significant amounts of various estrogenic chemicals were bioaccumulated in fat samples. It therefore seems likely that the lesions found in RNR and SNR were associated with the relatively high body-burden of environmental pollutants (phenols), although the possibility of systemic infections cannot be ruled out. No testicular abnormalities were found in reference eland. These findings are the first indication of mammalian wildlife being affected by environmental pollution of endocrine disrupting chemicals in South Africa.

Nationwide outbreak of STEC O157 infection in the Netherlands, December 2008-January 2009: continuous risk of consuming raw beef products

The Netherlands experienced a nationwide outbreak of Shiga toxin-producing Escherichia coli (STEC) O157 with onset of symptoms from the end of December 2008 until the end of January 2009. A total of 20 laboratory-confirmed cases were linked to the outbreak strain, serotype O157: H-, stx1, stx2, eae and e-hly positive. The investigation into the source of this outbreak is still ongoing, but evidence so far suggests that infection occurred as a result of consuming contaminated raw meat (steak tartare).

Nationwide outbreak of STEC O157 infection in the Netherlands, December 2008-January 2009: continuous risk of consuming raw beef products

The Netherlands experienced a nationwide outbreak of Shiga toxin-producing Escherichia coli (STEC) O157 with onset of symptoms from the end of December 2008 until the end of January 2009. A total of 20 laboratory-confirmed cases were linked to the outbreak strain, serotype O157: H-, stx1, stx2, eae and e-hly positive. The investigation into the source of this outbreak is still ongoing, but evidence so far suggests that infection occurred as a result of consuming contaminated raw meat (steak tartare).

An international outbreak of Shiga toxin-producing Escherichia coli O157 infection due to lettuce, September-October 2007

Between 14 September and 20 October 2007, an outbreak of Shiga toxin-producing Escherichia coli (STEC) O157 simultaneously occurred in the Netherlands and Iceland. A total of 50 laboratory-confirmed cases were reported with a STEC O157 infection caused by the same clone. The strain was of type O157:H-, PT8, positive for stx1, stx2, eae and e-hly, and sorbitol negative. The most probable cause of this international outbreak was contaminated lettuce, shredded and pre-packed in a Dutch food processing plant. Samples of the environment, raw produce and end products, taken at several vegetable growers and processing plants all tested negative for STEC O157. However, the only epidemiological link between the cases in the Netherlands and in Iceland was the implicated Dutch processing plant. In Europe, food products are often widely distributed posing the risk of potential spread of food borne pathogens simultaneously to several countries. This international outbreak emphasises the importance of common alert and surveillance systems in earlier detection of international outbreaks and better assessment of their spread.

Vitamin B12 status and rate of brain volume loss in community-dwelling elderly

OBJECTIVES

To investigate the relationship between markers of vitamin B(12) status and brain volume loss per year over a 5-year period in an elderly population.

METHODS

A prospective study of 107 community-dwelling volunteers aged 61 to 87 years without cognitive impairment at enrollment. Volunteers were assessed yearly by clinical examination, MRI scans, and cognitive tests. Blood was collected at baseline for measurement of plasma vitamin B(12), transcobalamin (TC), holotranscobalamin (holoTC), methylmalonic acid (MMA), total homocysteine (tHcy), and serum folate.

RESULTS

The decrease in brain volume was greater among those with lower vitamin B(12) and holoTC levels and higher plasma tHcy and MMA levels at baseline. Linear regression analysis showed that associations with vitamin B(12) and holoTC remained significant after adjustment for age, sex, creatinine, education, initial brain volume, cognitive test scores, systolic blood pressure, ApoE epsilon4 status, tHcy, and folate. Using the upper (for the vitamins) or lower tertile (for the metabolites) as reference in logistic regression analysis and adjusting for the above covariates, vitamin B(12) in the bottom tertile (<308 pmol/L) was associated with increased rate of brain volume loss (odds ratio 6.17, 95% CI 1.25-30.47). The association was similar for low levels of holoTC (<54 pmol/L) (odds ratio 5.99, 95% CI 1.21-29.81) and for low TC saturation. High levels of MMA or tHcy or low levels of folate were not associated with brain volume loss.

CONCLUSION

Low vitamin B(12) status should be further investigated as a modifiable cause of brain atrophy and of likely subsequent cognitive impairment in the elderly.

STEC O157 outbreak in the Netherlands, September-October 2007

Early in October 2007, an increase in notifications of human cases infected with Shiga toxin (Stx)-producing Escherichia coli (STEC) O157 was seen in the Netherlands.

Simultaneous exposure to low concentrations of dichlorodiphenyltrichloroethane, deltamethrin, nonylphenol and phytoestrogens has negative effects on the reproductive parameters in male Spraque-Dawley rats

Many reports suggest that male reproductive health has deteriorated over the last decades, possibly due to environmental contaminants that act as endocrine disruptors. This hypothesis was tested in Sprague-Dawley rats using a modified Organization for Economic Cooperation and Development 415 one-generation test. Group A received cottonseed oil as control, and Groups B, C and D received deltamethrin (DM); DM and dichlorodiphenyltrichloroethane (DDT); and DM, DDT, phytoestrogens and p-nonylphenol, respectively. Rats were exposed in utero and then received the substances for 10 weeks. The seminal vesicle mass (Group B; P = 0.046) and sperm count [Groups C (P = 0.013) and D (P = 0.003)] were lower and the anogenital distance [Group B (P = 0.047) C (P = 0.045) and D (P = 0.002)] shorter compared with the control group. The seminiferous tubule diameter [Groups B (P = <0.001), C (P = <0.001) and D (P = <0.001)] and epithelium thickness [Groups B (P = 0.030), C (P = <0.001) and D (P = <0.001)] were smaller compared with the control. The histology of the testes showed signs of apical sloughing and vacuolisation. Liver weights [Groups C (P = 0.013) and D (P = 0.005)] and liver enzymes [Group D (P = 0.013)] were also affected. These findings may indicate that simultaneous exposure to endocrine disrupting compounds contributes to the deterioration observed in male reproductive health.

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.

Lethal dose and reproductive parameters of p-nonylphenol in rats

Male reproductive abnormalities may be due to an increased level of maternal estrogens affecting the developing fetus. Man is exposed to environmental estrogens in multiple ways: diet, drinking water, air, and skin, para-Nonylphenol (p-NP), an alkylphenol, has estrogenic properties. This study was performed to evaluate the potency and workable concentrations before reproductive tests could be performed. The oral LD50 (median lethal dose) value for rats was 1475 mg/kg. For both males in the reproductive test the litter size after long-term treatment at 50 mg/kg p-NP was smaller than that in the breeding records. Five females did not conceive at all.

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.

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.

Effect of rotation on the generation of reactive oxygen species in human semen

Rotation of semen after liquefaction is a standard procedure in an Andrology laboratory. During rotation under aerobic conditions the semen is exposed to oxygen. Oxygen toxicity induces lipid peroxidation which is responsible for the loss of sperm function. The generation of reactive oxygen species was significantly increased after rotation. This may have a detrimental effect on sperm function during assisted reproduction.

Fibrin and fibrinogen degradation products with an intact D-domain C-terminal gamma chain inhibit an early step in accessory cell-dependent lymphocyte mitogenesis

Although the low molecular weight degradation products of fibrinogen (FgDP) and fibrin (FbDP) are known to inhibit lymphocyte blastogenesis, the effect of purified macro-molecular FgDP and FbDP (molecular weight, 90 to 200 Kd) is unclear. We have examined the effect of these latter FgDP and FbDP and find that products that contain the D domain inhibit lymphocyte proliferation in response to T-cell mitogens, allogeneic mononuclear leukocytes, and anti-CD3 in vitro. Plasmic digestion of D1 in the absence of calcium with removal of the C-terminal end of the gamma chain or disruption of the gamma-gamma C-terminal cross-link site of D-dimer (DD) by puffadder venom (PAV-D) abrogates their inhibitory potential. Prior incubation of monocytes with DD or D1 inhibits subsequent lymphocyte transformation. Binding studies with radiolabeled DD and PAV-D confirm that monocytes interact only with DD. This specific binding may be competitively inhibited by monoclonal antibodies to CD11b/CD18 or by peptide analogues of the C-terminal gamma chain of fibrinogen that mimic the adhesion recognition site of integrins. We postulate that DD and D1 bind to CD11b/CD18 on adherent monocytes and modulate lymphocyte activation. These products are typically present in the plasma of patients with disseminated intravascular coagulation with sepsis and could therefore influence inflammatory processes in vivo.

Seasonal incidence of Karoo paralysis in relation to the infestation density of female Ixodes rubicundus

The epidemiology of Karoo paralysis, induced by the tick Ixodes rubicundus, was investigated in a paralysis-enzootic area of the southwestern Orange Free State, Republic of South Africa. Sheep became paralysed during the last week of April and the first week of May during the 1985 and 1986 seasons, respectively. Paralysis cases were recorded up until July, but most paralysis cases occurred during the first week of May with a second but smaller peak occurring during June. Tick numbers on paralysed sheep closely followed peak periods in paralysis. A total of 65 and 50% of the naive sheep became paralysed during the 1985 and 1986 seasons, respectively. The seasonal pattern of tick infestation by female I. rubicundus was similar on both previously exposed and on naive sheep. The results of this study indicate that a certain number of ticks per kilogram host body mass is required before symptoms of paresis of paralysis are observed. In general the tick burden per kilogram host mass was significantly greater in paralysed compared to non-paralysed sheep. The range in the number of ticks per kilogram host mass may, however, overlap between non-paralysed and paralysed groups. Previously exposed or previously paralysed sheep are less susceptible to paralysis in the following year. Differences in susceptibility between individual sheep seems likely.

The effect of the pattern of attachment weights of female Ixodes rubicundus on Karoo paralysis in a naturally infested flock of sheep

The weights of feeding female Ixodes rubicundus attaching to sheep was studied in a natural focus of Karoo paralysis. The studies showed fewer females in the middle weight ranges and more in the heavier and lighter categories than would be expected if the distribution was normal. Weights were also strongly skewed towards the lighter females between 0 and 400 mg. No differences in the pattern of attachment weights occurred over the four experimental groups used, suggesting that previous contact of sheep with I. rubicundus had no effect on the ability of the tick to engorge.