Urinary levels of bisphenol A, benzophenones and parabens in Tunisian women: A pilot study.

Bisphenol A (BPA), benzophenones and parabens are commonly used in the production of polycarbonate plastics, as UV-filters and as antimicrobial preservatives, respectively, and they are thought to exhibit endocrine disrupting properties. Exposure to these compounds remains poorly characterized in developing countries, despite the fact that certain behaviors related to westernization have the potential to influence exposure. The aim of this pilot study was to measure urinary concentrations of BPA, six different benzophenones and four parabens in 34 Tunisian women. In addition, we identified some socio-demographic and dietary predictors of exposure to these compounds. Chemical analyses were carried out by dispersive liquid-liquid microextraction (DLLME) and ultra-high performance liquid chromatography with tandem mass spectrometry detection (UHPLC-MS/MS). Detection frequencies of methylparaben (MP), ethylparaben (EP) and propylparaben (PP) ranged between 67.6 and 94.1%. Butylparaben (BP) was found in 38.2% of the analyzed samples; BPA in 64.7%; and benzophenone-1 (BP-1) and benzophenone-3 (BP-3) were detected in 91.2 and 64.7% of the analyzed samples, respectively. Urinary geometric mean concentrations of MP, EP, PP, and BP were 30.1, 1.4, 2.0 and 0.5ngmL(-1), respectively. Geometric mean concentrations of BPA, BP-1, and BP-3 were 0.4, 1.3 and 1.1ngmL(-1), respectively. Our results suggest that Tunisian women are widely exposed to BPA, parabens and some benzophenones. Further studies on the general Tunisian population are needed in order to assess the levels of exposure to these compounds and to identify sources of exposure and population groups at higher risk.

Zearalenone and its metabolites in urine and breast cancer risk: a case-control study in Tunisia.

Zearalenone (ZON) is a non-steroidal estrogenic mycotoxin produced by Fusarium species. The exposure risk to humans and animals is the consumption of contaminated food and animal feeds. It has been reported that ZON and some of its metabolites promote the development of hormone-dependent tumors. The aim of this case-control study was to estimate exposure to ZON and its five metabolites (α-zearalenol [α-ZOL], ß-zearalenol [ß-ZOL], α-zearalanol [zeranol, α-ZAL], ß-zearalanol [teranol, ß-ZAL] and zearalanone [ZAN]) by measuring urinary concentrations of these compounds, and to evaluate the risk of breast cancer related to this exposure. Chemical analyses were carried out by liquid-liquid extraction (LLE) and ultra-high performance liquid chromatography with tandem mass spectrometry detection (UHPLC-MS/MS). Statistical analyses were performed in order to determine the association between exposure to these compounds and the development of breast cancer. Crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were calculated by unconditional logistic regression to estimate the magnitude of the associations. The obtained results (adjusted OR=1.54, 95% CI=1.10-2.77) suggest a potential role of α-ZAL in the risk of developing breast cancer.

Serum levels of persistent organic pollutants and predictors of exposure in Tunisian women.

INTRODUCTION: In spite of the international consensus on the human health risks associated with exposure to persistent organic pollutants (POPs), the Tunisian population is suspected to have been inadvertently exposed to POPs over the last decades. OBJECTIVES: The aim of this study was to evaluate POP concentrations in the serum of a subset of 54 Tunisian women and to identify some socio-demographic and dietary predictors of exposure to POPs. RESULTS: Of the ten POPs analyzed, three polychlorinated biphenyl (PCB) congeners (-138, -153 and -180), and two organochlorine pesticides (OCPs), HCB and p,p'-DDE, showed frequencies ranging from 98 to 100%. Serum median concentrations of PCB congeners (-138, -153 PCB-180) were 26.08, 119.1 and 29.84 ng/g lipid, respectively, and median concentrations of HCB and p,p'-DDE were 19.98 and 127.59 ng/g lipid, respectively. Age was positively correlated with serum levels of selected POPs. Women living in northern Tunisia showed higher serum levels of all PCBs. Working outside home and cereal consumption were positively associated to serum levels of p,p'-DDE. The duration of the lactation was also related to lower serum levels of p,p'-DDE and HCB. CONCLUSION: The levels of exposure to POPs found warrant a biomonitoring program in order to identify routes of exposure and population groups at higher risk. This program will help to establish prevention policies and to determine the association between exposure to POPs and chronic diseases.

Validation of a UHPLC-MS/MS method for quantification of zearalenone, α-zearalenol, ß-zearalenol, α-zearalanol, ß-zearalanol and zearalanone in human urine.

Humans can be exposed to mycotoxins through the diet. Evaluation of exposure levels to mycotoxins can be performed by direct determination in urine. The present work proposes a sensitive ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the determination of zearalenone (ZON) and its five metabolites (α-zearalenol [α-ZOL], ß-zearalenol [ß-ZOL], α-zearalanol [zeranol, α-ZAL], ß-zearalanol [teranol, ß-ZAL] and zearalanone [ZAN]) in human urine samples. The method involves the enzymatic hydrolysis of the samples, extraction of the analytes using liquid-liquid extraction (LLE) with ethyl acetate/formic acid (99:1 v/v) and a cleanup step using hexane, prior to their quantification by UHPLC-MS/MS, using an electrospray ionization (ESI) interface in the negative mode. Zearalenone-d6 (ZON-d6) was used as surrogate. The limits of detection and the limits of quantification ranged from 0.03 to 0.3ngmL(-1) and from 0.1 to 1.0ngmL(-1), respectively. The method was validated using matrix-matched calibration and a spike recovery assay. Recovery rates for spiked samples ranged from 96% to 104%, with relative standard deviations lower than 8.5%. This method was satisfactorily applied to 42 urine samples from Tunisian women for the determination of zearalenone and its five metabolites.

Ochratoxin A levels in human serum and foods from nephropathy patients in Tunisia: where are you now?

Ochratoxin A is a natural mycotoxin with nephrotoxic properties that can contaminate food products. It has been detected in high amount in human serum collected from nephropathy patients, especially those categorized as having a chronic interstitial nephropathy of unknown etiology. In the present study, ochratoxin A levels were measured in commonly consumed food items and in serum samples from nephropathy and healthy subjects in Tunisia. To assess ochratoxin A, a high performance liquid chromatography method was optimized. The ochratoxin A assay showed very different scales of ochratoxin A serum and food contamination from 0.12 to 1.5 ng/mL and 0.11 to 6.1 ng/g respectively, and in healthy subjects and 0.11 to 33.8 ng/g for food and 0.12 to 3.8 ng/mL for serum in nephropathy patients suffering from chronic interstitial nephropathy of unknown etiology. The disease seems related to ochratoxin A serum levels and food contaminations, since the healthy group was significantly different from the nephropathy group (P<0.001) for both food and serum ochratoxin A contamination. Those results combined with data published already, emphasize the likely endemic aspect of ochratoxin A-related nephropathy occurring in Tunisia.

Serum levels of ochratoxin A in healthy subjects and in nephropathic patients in Tunisia.

Ochratoxin A is a fungal toxin produced by Aspergillus and Penicillinium. These Fungi oftenly contaminate plant-derived products, and can generate deleterious toxic effects in man. In this study, ochratoxin A was determined in human serum samples collected in Tunisia, using high performance liquid chromatography (HPLC) and fluorescence detection. The samples were collected from healthy subjects (n = 105) as well as from patients with various kidney disorders. Five different kinds of kidney disorders were represented: transplanted subjects (27), patients with Chronic Interstitial Nephropathy (22) of known etiology, Chronic Vascular Nephropathy (26), Chronic Glomerular Nephropathy (26) or Chronic Interstitial Nephropathy (30) of unknown etiology. Mean concentrations of ochratoxin A in the healthy group was 0.49+/-0.79 ng/mL. The highest mean concentration of ochratoxin A was found in group of Chronic Interstitial Nephropathy of unknown etiology 1.25+/-1.22 ng/mL. Significant differences were also observed according to the geographic origin of healthy subjects and nephropthic patients within Tunisia.

Role of humoral mediators in, and influence of a liposomal formulation on, acute amphotericin B nephrotoxicity.

The mechanisms responsible for amphotericin B nephrotoxicity remain incompletely understood, but clearly involve reduction in renal blood flow and glomerular filtration rate. Both direct effects of amphotericin B on contractile vascular cells, and indirect effects, due to humoural mediators, have been proposed. This study examines the role of nitric oxide, endothelin and angiotensin II in the acute nephrotoxic effects of amphotericin B in rats, and compares the anti-fungal and nephrotoxic effects of liposomal amphotericin B and amphotericin B-deoxycholate. Anaesthetized rats were given infusions of amphotericin B-deoxycholate in the presence or absence of N-nitro-L-arginine, PD 145065, a non-specific endothelin receptor antagonist, and L-158809, an angiotensin II type I receptor antagonist, or increasing doses of liposomal amphotericin B. Amphotericin B-deoxycholate (0.03 mg/kg/min intravenously) caused a significant 44% reduction in glomerular filtration rate and 65% maximal fall in renal blood flow. N-Nitro-L-arginine-treated rats had a lower renal blood flow and glomerular filtration rate at baseline, but sustained similar reduction of 53% and 75% in these parameters, respectively. PD145065 and L-158809 did not modify these effects either. Increasing doses of liposomal amphotericin B (from 0.01 up to 0.50 mg/kg/min.) induced no change in either glomerular filtration rate or renal blood flow. In vitro susceptibility tests revealed similar potency for liposomal amphotericin B and amphotericin B-deoxycholate in their fungistatic effects and slightly higher potency for amphotericin B-deoxycholate in their fungicidal effect. These results suggest that endogenous endothelin, angiotensin II or nitric oxide systems are not involved in the nephrotoxic effects of amphotericin B. The liposomal amphotericin B results suggest that amphotericin B nephrotoxicity is due to a direct interaction of amphotericin B with renal cells that is prevented by its encapsulation in liposomes.

Mononuclear cell proliferation and hyperplasia during Wallerian degeneration in the visual system of the goldfish in the presence or absence of regenerating optic axons.

Patterns of proliferation and changes in non-neuronal cell number in the visual system of the goldfish have been quantitatively examined during optic axon regeneration after an optic nerve crush (ONC). In addition, in order to examine the effect of the regenerating axons on cellular responses in the visual pathways, we did a similar analysis of animals with the right eye removed (ER). Finally, we used double labeling protocols to demonstrate that the proliferating cells that we were counting were mostly phagocytic cells of the mononuclear lineage. In animals with an ONC, we observed an early burst of proliferation that peaked between 7 and 14 days after surgery in all parts of the visual system. In the optic tract, there was also a secondary rise that peaked at 21 days. Levels of proliferation returned to normal by 32 days postoperative in the tract and tectum, while they remained somewhat elevated in the optic nerve for at least 93 days. The total number of non-neuronal cells in the visual paths also rose to peak values between 7 and 14 days after ONC surgery. In the optic tract and tectum, the values fell rapidly after this time, while in the optic nerve, there was a secondary peak at 32 days after which values remained elevated for the duration of the experiment. As compared to animals with an ONC, enucleation resulted in elevated proliferation and hyperplasia at early postoperative intervals. However, because these differences occurred when axons had not yet regenerated into the affected structures, these data do not provide strong evidence for a direct effect of regenerating optic axons on the early cellular responses during Wallerian degeneration in the goldfish. In addition, in the tectum, there was an early increment in cell number that was not associated with elevated levels of proliferation. We believe that this increment represents immigration of resident microglia from other regions of the brain.

A clinical comparison of Dacron patch closure of small-caliber carotids compared with primary closure of large-caliber carotids after endarterectomy.

The objective was to study results of carotid endarterectomies performed between 1975 and 1991, comparing primary closure to Dacron patch closure. This was a retrospective study. Data from patient follow-up by physical examination, chart review, and Duplex study were used. Scan data were obtained in 92 of the primary cases, at a mean of 5 years postoperatively, and in 63 of the patch cases, at a mean of 4.1 years postoperatively. During this period, 269 endarterectomies were closed primarily and 101 were closed with a knitted Dacron patch. Twenty patients in the primary group and nine patients with patch closure were lost to follow-up, which extended for up to 12.5 years, with a mean of 4.7 +/- 3.6 years. No acute closures, infections or aneurysms developed in either group. Perioperative stroke incidence was 4.1 per cent for primary closure and 3.0 per cent for the patch group (P > 0.05). Late stenosis occurred in 17.3 per cent of the primary group and 11.1 per cent of the patch closure group (P > 0.05). Five-year survival was 76.2 per cent in the primary group, compared with 79.2 per cent for patch closure. Late stroke incidence was 2.8 per cent in the primary group and 3.3 per cent in the patch closure group. Results of smaller (< or = 3.5 mm) carotid arteries closed with knitted Dacron patches are equivalent to those of larger carotid arteries closed primarily.

The effect of flow shear stress on endothelialization of impervious Dacron grafts from circulating cells in the arterial and venous systems of the same dog.

The purpose of this report was to study effects of shear force and hemodynamic conditions that influence fallout healing in the arterial and venous systems of the same dog. Knitted Dacron grafts made impervious by a 1.5 mm thick coat of silicone rubber bonded to the external surface were implanted for 4 weeks during the same surgery in the descending thoracic aorta (DTA), abdominal aorta (AA) and inferior vena cava (IVC) of each of five dogs. Flow rates were measured during surgery and shear stresses calculated with the Hagen-Poiseuille formula. Full-wall thickness longitudinal tissue sections were embedded in resin and stained with hematoxylin and eosin for light microscopy, and in paraffin for immunocytochemistry studies with Factor VIII/von Willebrand factor, smooth muscle alpha-actin, collagen IV, laminin, and proliferating cell nuclear antigen. Scanning electron microscopy and transmission electron microscopy studies were also performed. AgNO3 was used to determine percentage of endothelial-like cell coverage on the flow surface. All grafts were patent, without hematoma or seroma. Endothelial-like cell coverage was highest in the IVC grafts and lowest in the DTA. Shear stress and flow velocity were significantly lower in IVC grafts than DTA and AA. Proliferating cell nuclear antigen indicated extensive cellular proliferation in the intima and in the interstices of the inner portion of the graft wall. The degree of fallout healing in knitted Dacron grafts made impervious by an external coat of silicone rubber varies inversely with the sheer force of blood flow in these grafts.

Apparent blood stream origin of endothelial and smooth muscle cells in the neointima of long, impervious carotid-femoral grafts in the dog.

The purpose of this study was to determine whether endothelial and smooth muscle cells originating from the blood stream contribute to the endothelialization of impervious, small-caliber, long Dacron grafts used as extraanatomical bypasses in dogs. We implanted silicone-rubber-coated, permanently impervious grafts 64 to 77 cm long and 6 mm in diameter, made of externally supported knitted Dacron as unilateral carotid-femoral bypasses with distal femoral arteriovenous fistulae in 10 dogs for 3 months; sides were alternated between cases. Subjects received 162 mg/day of aspirin, and its effectiveness on platelet aggregation (PA) was evaluated and expressed as a PA score. Graft healing was studied by stereomicroscopy with silver nitrate staining, by light microscopy with hematoxylin-eosin and immunocytochemical staining for endothelial and smooth muscle cells, and by scanning and transmission electron microscopy. Five grafts were patent for 3 months and could be included in the healing study; the five occluded grafts thrombosed within 14 days. Although there was no transinterstitial tissue ingrowth from perigraft tissues into the impervious Dacron grafts, scattered islands of endothelial cells were conclusively demonstrated on graft flow surfaces 3 months after implantation. Average endothelial-like cell coverage of the flow surfaces was 15.6% +/- 3.8%, and alpha-actin-positive smooth muscle cells and microvessels were found beneath some of the endothelial islands. These findings suggest that blood stream-derived endothelial and smooth muscle cells play a role in the healing of the inner wall of Dacron grafts in the dog.

Endothelium on the flow surface of human aortic Dacron vascular grafts.

PURPOSE: We have previously observed endothelium on two human vascular prostheses explanted under optimal conditions for flow surface preservation. In this study we sought to further verify the hypothesis that endothelialization can occur on clinical grafts and that it can be detected in specimens that have been promptly removed and properly preserved in a timely manner. METHODS: We studied 29 aortic grafts. Of these, 11 Dacron bypass grafts were in a condition suitable for analysis with light microscopy and immunocytochemistry staining, and scanning and transmission electron microscopy. RESULTS: Three grafts had endothelium beyond the pannus, identified by factor VIII/ vWF, Ulex europaeus agglutinin, and collagen IV positivity. Specimen A, a knitted 6-year implant, was preserved by embalming 3 hours after the patient's death and had a firmly attached outer capsule with fibroblasts, collagen, giant cells, and microvessels in the interstices. Specimen B, a woven 18-year implant, was retrieved at reoperation and immediately fixed in 10% formalin; it had no outer capsule and no tissue ingrowth. Specimen C, a woven 7-year implant, was removed and fixed 5 hours after the patient's death; it had a firmly attached outer capsule but no tissue ingrowth beyond the outer portion of the wall. CONCLUSIONS: The rapidity with which the specimens were fixed probably enabled identification of endothelium. These findings suggest that endothelialization of synthetic arterial grafts may occur more frequently in human beings than previously recognized.

Accelerated endothelialization model for the study of Dacron graft healing.

Accelerated endothelialization was studied by creating a vascular tissue environment around porous Dacron grafts. Three study groups, each containing 10 dogs, were divided equally into 2- and 4-week implant periods, with 8 mm x 6 cm knitted Dacron grafts implanted in the abdominal aorta. Grafts in group 1, the control group, were implanted conventionally. In group 2 each implanted graft was completely wrapped in a resected segment of the autogenous inferior vena cava, with its intima against the wall. In group 3 the adventitial side of the vein was wrapped against the wall. The vein wrap produced accelerated endothelialization as follows: endothelial-like cell coverage scores at 2 and 4 weeks were, respectively, 78% and 98% for group 2 and 80% and 95% for group 3, compared to only 14% and 50% for group 1 (p < 0.05). The neointima, which contained smooth muscle cells, was formed as early as 2 weeks in the vein-wrapped grafts. There were no differences in the speed of healing or in healing patterns according to whether the intimal or the adventitial side of the inferior vena cava was placed against the graft. Histologic findings did not support the hypothesis that accelerated flow surface endothelialization results in direct migration of endothelial cells from the intima of the vein wrap, and there was no clear correlation between the surface endothelial-like cell coverage and microostia. To gain further insight into why accelerated healing occurs in this model, earlier observations accompanied by molecular biology analysis are needed, and vein wrap studies provide a method of comparison for this work.

Implant site influence on arterial prosthesis healing: a comparative study with a triple implantation model in the same dog.

PURPOSE: The purpose of this study was to develop a cost-effective canine graft healing model that gives information on various implant sites and controls for variable factors between graft locations and between animals and to compare the influence of implant site (retropleural, retroperitoneal, and subcutaneous areas) on arterial graft healing in the same subject under such controlled study conditions. METHODS: Five mongrel dogs were studied for 8 weeks, and one was studied for 3 years. Each received three porous Dacron grafts during the same surgery: a carotid-femoral bypass (C-FB) and interposition grafts in the descending thoracic aorta and abdominal aorta. To produce comparable shear stress calibers of the C-FB and abdominal aorta grafts were 2 mm less than those of the descending thoracic aorta, and a distal arterio-venous fistula was created to further increase the C-FB flow. For comparable blood aggregation status platelet aggregation was preevaluated and adjusted with antiplatelet agents. Graft flow surfaces were assessed for thrombus-free surface and endothelial-like cell coverage scores. Tissue samples were studied with hematoxylin-eosin, factor VIII/ von Willebrand factor, smooth muscle alpha-actin staining, and scanning electron microscopy and transmission electron microscopy. RESULTS: All grafts were patent. Shear stress for the three grafts and platelet aggregation among the study subjects were comparable. Healing of descending thoracic aorta and abdominal aorta grafts was similar, but C-FB healing was slow, incomplete, and uneven, with a high incidence of seroma. Eight-week and 3-year results were comparable. CONCLUSIONS: This model gives broad healing information about the areas where grafts are often implanted in humans. Eight weeks appears to be a sufficient period to reflect basic and general healing characteristics. Grafts heal better in the retropleural and retroperitoneal areas than in the subcutaneous tissues.

Transcranial Doppler intraoperative monitoring during carotid endarterectomy: experience with regional or general anesthesia, with and without shunting.

To determine whether continuous transcranial Doppler (TCD) can significantly alter therapeutic conduct during carotid endarterectomy, a retrospective study of 117 carotid endarterectomies was done. There was no perioperative mortality; one perioperative stroke was recorded in a patient who was symptomatic preoperatively. Continuous TCD of the ipsilateral middle cerebral artery (MCA) was attempted in 99 cases, and successful in 90; nine patients (9.1%) had inadequate temporal windows for MCA access. MCA velocities and emboli were recorded before and during carotid cross-clamping, and on clamp release. There were no significant velocity differences between the patients with regional and general anesthesia, and patients with and without carotid shunts, but there was a statistically significant difference in the total number of emboli (air and particulate transients) noted for the shunted and nonshunted patients after clamp release: 12.7 versus 23.6, respectively (p = 0.05). There was no significant difference when particulate and air microemboli were compared. During surgery TCD identified residual flow of less than 40% in the MCA in 17 patients (18.8%). TCD also identified hyperperfusion in two patients, shunt abnormalities in three patients, and influenced postop treatment in four patients, one of whom was returned to surgery. TCD is an important tool for identifying patients who would benefit from a shunt, preventing hyperperfusion, identifying postop emboli, and detecting technical errors.

Effect of differential shear stress on platelet aggregation, surface thrombosis, and endothelialization of bilateral carotid-femoral grafts in the dog.

PURPOSE: The purpose of this study was to determine the effects of increased shear stress on the aggregability of platelets as they traverse a long, small-caliber (6 mm) Dacron graft in the dog and on the surface thrombosis and endothelialization of such a graft. METHODS: Each of nine dogs received bilateral carotid-femoral artery grafts, approximately 75 cm long, for 3 months; one graft of each pair had a distal femoral arteriovenous fistula to produce a higher shear rate than the contralateral graft. Platelet aggregation scores were determined on blood withdrawn from the external jugular vein and from the proximal and distal ends of the grafts in each animal. Graft flow rates, which were used in the computation of shear stress, and luminal pressure gradients through grafts were measured during surgery and specimen retrieval. Specimens were studied with light microscopy after hematoxylin and eosin and immunocytochemical staining and by scanning electron and transmission electron microscopy to evaluate the nature, composition, and thickness of the flow surface lining, as well as the transmural healing. RESULTS: Two high-shear stress and two low-shear stress grafts occluded unilaterally; five dogs had bilaterally patent grafts, allowing comparative analyses. All subjects had low platelet aggregability with aspirin. Platelet aggregation scores taken from proximal and distal ends of the grafts were not significantly different. The high-shear stress grafts had significantly more endothelial-like cell coverage (p < 0.0371) than the low-shear stress grafts, less flow-surface thrombus (p < 0.0056), and a thinner surface lining (p < 0.0029), on both the neointima and pseudointima. CONCLUSIONS: In subjects with low platelet aggregation scores, long Dacron grafts do not elevate platelet aggregability of blood flowing through them. High-shear stress grafts have less flow surface thrombus, more endothelialization, and a thinner surface lining than do low-shear stress grafts.

Erythromycin-associated ergotamine intoxication: arteriographic and electrophysiologic analysis of a rare cause of severe ischemia of the lower extremities and associated ischemic neuropathy.

Vasospasm associated with ergotamine is a well-known phenomenon. In this case report we present a rare drug interaction between erythromycin and ergotamine at normal doses causing lower extremity ischemia in a 36-year-old woman. Nitroprusside proved to be the treatment of choice. The response was dramatic and took place in a matter of hours in this patient. Ischemic monomelic neuropathy is a recently described entity in which axonal necrosis is caused by a loss of distal extremity blood flow. The association between erythromycin and ergotamine may be a dangerous pharmacologic combination; drugs that have a hepatic cycle with ergotamine derivatives must be used with caution.