Ultrasonic and Electrokinetic Remediation of Low Permeability Soil Contaminated with Persistent Organic Pollutants

Electrokinetics has emerged as a potential technique for in situ soil remediation and especially unique because of the ability to work in low permeability soil. In electrokinetic remediation, non-polar contaminants like most organic compounds are transported primarily by electroosmosis, thus the process is effective only if the contaminants are soluble in pore fluid. Therefore, enhancement is needed to improve mobility of these hydrophobic compounds, which tend to adsorb strongly to the soil. On the other hand, as a novel and rapidly growing science, the applications of ultrasound in environmental technology hold a promising future. Compared to conventional methods, ultrasonication can bring several benefits such as environmental friendliness (no toxic chemical are used or produced), low cost, and compact instrumentation. It also can be applied onsite. Ultrasonic energy applied into contaminated soils can increase desorption and mobilization of contaminants and porosity and permeability of soil through developing of cavitation. The research investigated the coupling effect of the combination of these two techniques, electrokinetics and ultrasonication, in persistent organic pollutant removal from contaminated low permeability clayey soil (with kaolin as a model medium). The preliminary study checked feasibility of ultrasonic treatment of kaolin highly contaminated by persistent organic pollutants (POPs). The laboratory experiments were conducted in various conditions (moisture, frequency, power, duration time, initial concentration) to examine the effects of these parameters on the treatment process. Experimental results showed that ultrasonication has a potential to remove POPs, although the removal efficiencies were not high with short duration time. The study also suggested intermittent ultrasonication over longer time as an effective means to increase the removal efficiencies. Then, experiments were conducted to compare the performances among electrokinetic process alone and electrokinetic processes combined with surfactant addition and mainly with ultrasonication, in designed cylinders (with filtercloth separating central part and electrolyte parts) and in open pans. Combined electrokinetic and ultrasonic treatment did prove positive coupling effect compared to each single process alone, though the level of enhancement is not very significant. The assistance of ultrasound in electrokinetic remediation can help reduce POPs from clayey soil by improving the mobility of hydrophobic organic compounds and degrading these contaminants through pyrolysis and oxidation. Ultrasonication also sustains higher current and increases electroosmotic flow. Initial contaminant concentration is an essential input parameter that can affect the removal effectiveness.

Trisomy 13 mosaicism demonstrated only in skin fibroblasts in a patient presenting psychomotor retardation, pigmentary dysplasia and some dysmorphic features

A Brazilian female infant presented delayed psychomotor development, skin pigmentary dysplasia and some dysmorphic features. Chromosome analysis from peripheral blood culture was normal, but the karyotype from skin fibroblasts revealed mosaicism for trisomy 13. This case demonstrates the relevance of performing chromosomal analysis of skin fibroblasts in patients with mental retardation, associated with pigmentary dysplasia of the skin and a normal karyotype in peripheral blood lymphocytes. To our knowledge, it is the first report of trisomy 13 demonstrated only in skin fibroblasts.

Inhibitory effect of high [Mg2+] on the vasopressin-stimulated hydroosmotic permeability of the isolated perfused cortical collecting duct

High magnesium concentration inhibits the effect of arginine vasopressin (AVP) on smooth muscle contraction and platelet aggregation and also influences hepatocyte AVP receptor binding. The aim of this study was to determine the role of magnesium concentration [Mg2+] in AVP-stimulated water transport in the kidney collecting duct. The effect of low and high peritubular [Mg2+] on the AVP-stimulated osmotic water permeability coefficient (Pf) was evaluated in the isolated perfused rabbit cortical collecting duct (CCD). Control tubules bathed and perfused with standard Ringer bicarbonate solution containing 1 mM Mg2+ presented a Pf of 223.9 ± 27.2 µm/s. When Mg2+ was not added to the bathing solution, an increase in the AVP-stimulated Pf to 363.1 ± 57.2 µm/s (P<0.05) was observed. An elevation of Mg2+ to 5 mM resulted in a decrease in Pf to 202.9 ± 12.6 µm/s (P<0.05). This decrease in the AVP-stimulated Pf at 5 mM Mg2+ persisted when the CCDs were returned to 1 mM Mg2+, Pf = 130.2 ± 20.3 µm/s, and was not normalized by the addition of 8-[4-chlorophenylthio]-adenosine 3',5'-cyclic monophosphate, a cAMP analogue, to the preparation. These data indicate that magnesium may play a modulatory role in the action of AVP on CCD osmotic water permeability, as observed in other tissues.

The molecular basis of selective permeability of connexins is complex and includes both size and charge

Although gap junction channels are still widely viewed as large, non-specific pores connecting cells, the diversity in the connexin family has led more attention to be focused on their permeability characteristics. We summarize here the current status of these investigations, both published and on-going, that reveal both charge and size selectivity between gap junction channels composed of different connexins. In particular, this review will focus on quantitative approaches that monitor the expression level of the connexins, so that it is clear that differences that are seen can be attributed to channel properties. The degree of selectivity that is observed is modest compared to other channels, but is likely to be significant for biological molecules that are labile within the cell. Of particular relevance to the in vivo function of gap junctions, recent studies are summarized that demonstrate that the connexin phenotype can control the nature of the endogenous traffic between cells, with consequent effects on biological effects of gap junctions such as tumor suppression.

Intestinal permeability in strongyloidiasis

The objective of the present study was to assess intestinal permeability in patients with infection caused by Strongyloides stercoralis. Twenty-six patients (16 women and 10 men), mean age 45.9, with a diagnosis of strongyloidiasis were evaluated. For comparison, 25 healthy volunteers (18 women and 7 men), mean age 44.9, without digestive disorders or intestinal parasites served as normal controls. Intestinal permeability was measured on the basis of urinary radioactivity levels during the 24 h following oral administration of chromium-labeled ethylenediaminetetraacetic acid (51Cr-EDTA) expressed as percentage of the ingested dose. The urinary excretion of 51Cr-EDTA was significantly reduced in patients with strongyloidiasis compared to controls (1.60 ± 0.74 and 3.10 ± 1.40, respectively, P = 0.0001). Intestinal permeability is diminished in strongyloidiasis. Abnormalities in mucus secretion and intestinal motility and loss of macromolecules could explain the impaired intestinal permeability.

No evidence for mutations in exons 1, 8 and 18 of the patched gene in sporadic skin lesions of Brazilian patients

There is strong evidence that the patched (PTCH) gene is a gene for susceptibility to the nevoid basal cell carcinoma syndrome. PTCH has also been shown to mutate in both familial and sporadic basal cell carcinomas. However, mutations of the gene seem to be rare in squamous cell carcinomas. In order to characterize the role of the gene in the broader spectrum of sporadic skin malignant and pre-malignant lesions, we performed a polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis of genomic DNA extracted from 105 adult patients (46 females and 59 males). There were 66 patients with basal cell carcinomas, 30 with squamous cell carcinomas, 2 with malignant melanomas and 7 patients with precancerous lesions. Two tissue samples were collected from each patient, one from the central portion of the tumor and another from normal skin. Using primers that encompass the entire exon 1, exon 8 and exon 18, where most of the mutations have been detected, we were unable to demonstrate any band shift. Three samples suspected to present aberrant migrating bands were excised from the gel and sequenced directly. In addition, we sequenced 12 other cases, including tumors and corresponding normal samples. A wild-type sequence was found in all 15 cases. Although our results do not exclude the presence of clonal alterations of the PTCH gene in skin cancers or mutations in other exons that were not screened, the present data do not support the presence of frequent mutations reported for non-melanoma skin cancer of other populations.

Skin secretion of Siphonops paulensis (Gymnophiona, Amphibia) forms voltage-dependent ionic channels in lipid membranes

The effect of the skin secretion of the amphibian Siphonops paulensis was investigated by monitoring the changes in conductance of an artificial planar lipid bilayer. Skin secretion was obtained by exposure of the animals to ether-saturated air, and then rinsing the animals with distilled water. Artificial lipid bilayers were obtained by spreading a solution of azolectin over an aperture of a Delrin cup inserted into a cut-away polyvinyl chloride block. In 9 of 12 experiments, the addition of the skin secretion to lipid bilayers displayed voltage-dependent channels with average unitary conductance of 258 ± 41.67 pS, rather than nonspecific changes in bilayer conductance. These channels were not sensitive to 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid or tetraethylammonium ion, but the experimental protocol used does not permit us to specify their characteristics.

Urethroplasty using a bovine pericardium graft: an experimental study using normal urethras from dogs

The use of bovine pericardium as a urethral patch to substitute a ventral segment of canine urethras was studied. Healing, epithelial growth, urethral permeability, fistulas, and calcification were analyzed. Thirty male mongrel dogs of medium and large size underwent resection of a ventral segment of the medial urethra measuring 2.0 x 0.5 cm, which was replaced with a bovine pericardium graft, treated with buffered glutaraldehyde and preserved in formaldehyde. Two running sutures of polygalactin 5-0 were applied, one on each side of the patch. The corpus spongiosum was closed with uninterrupted suture and the skin with interrupted suture of polygalactin 5-0. Six months later, the animals were examined and sacrificed under anesthesia. Retrograde urethrograms showed that the urethral healing was complete in six of the 30 animals, without stenosis, fistulas or dilations. Microscopic examination showed complete epithelization of these six urethras. The remaining 24 animals presented urethrocutaneous fistulas without stenosis, demonstrated by urethral catheterism using a 10-Fr plastic catheter. These data show that a successful urethral reconstruction of the penile urethra was possible in only 20% of the operated animals. Infection and leakage may be the cause of the urethrocutaneous fistulas present in 80% of cases. Further studies are necessary to determine whether such fistulas are avoidable. If they are, the bovine pericardium may well be an option in the treatment of urethral lesions in dogs.

Induction of oral tolerance and the effect of interleukin-4 on murine skin allograft rejection

We studied the effect of oral and portal vein administration of alloantigens on mouse skin allograft survival. Graft receptor BALB/c mice received spleen cells (30, 90, 150 or 375 x 10(6)) from donor C57BL/6 mice intragastrically on three successive days, starting seven days before the skin graft. Allograft survival was significantly increased with the feeding of 150 x 10(6) allogeneic spleen cells by one gavage (median survival of 12 vs 14 days, P <= 0.005) or when 300 x 10(6) cells were given in six gavage (12 vs 14 days, P < 0.04). A similar effect was observed when 150 x 10(6) spleen cells were injected into the portal vein (12 vs 14 days, P <= 0.03). Furthermore, prolonged allograft survival was observed with subcutaneous (12 vs 16 days, P <= 0.002) or systemic (12 vs 15 days, P <= 0.016) application of murine interleukin-4 (IL-4), alone or in combination with spleen cell injection into the portal vein (12 vs 18 days, P <= 0.0018). Taken together, these results showed that tolerance induction with spleen cells expressing fully incompatible antigens by oral administration or intraportal injection partially down-modulates skin allograft rejection. Furthermore, these findings demonstrated for the first time the effect of subcutaneous or systemic IL-4 application on allograft skin survival suggesting its use as a beneficial support therapy in combination with a tolerance induction protocol.

Normal skin of HIV-infected individuals contains increased numbers of dermal CD8 T cells and normal numbers of Langerhans cells

Dysregulation of the skin immune system (SIS) could explain the high prevalence of skin disorders in HIV+ individuals. The present study was carried out to determine whether alterations in the cell population of SIS and epidermal immunoactivation occur in the normal skin of HIV+ individuals. Forty-five biopsies were taken from the normal upper arm skin of 45 HIV+ patients and of 15 healthy controls. HIV+ individuals were divided into three categories according to their CD4 cell blood count (<200, 200-499 and ³500/µl). Hematoxylin-eosin was used to stain tissue sections for morphological analysis and immunohistochemistry was used for the evaluation of the frequency of macrophages, Langerhans cells, and CD lymphocyte subsets. In addition, semiquantitative analysis of LFA-1, ICAM-1 and HLA-DR was determined in epidermal cells. Macrophages, Langerhans cells, and CD lymphocyte subsets did not differ significantly between any of the patient categories and the control group. When all HIV+ individuals were compared as a group to the control group, a significant increase in dermal CD8+ T lymphocytes (P < 0.01) and lower CD4-CD8 ratios (P < 0.01) were observed in the HIV+ individuals. Epidermal ICAM-1 and HLA-DR expression was negative in both HIV+ and normal skin biopsies. No evidence of a depletion of the SIS population or of epidermal immunoactivation in normal skin from HIV+ individuals was demonstrable, suggesting that alterations in the central immune system are not necessarily reflected in the SIS of HIV-infected patients.

Skin morphology of the mutant hairless USP mouse

The morphology of the skin of the mutant hairless USP mouse was studied by histological, histochemical and immunohistochemical methods and compared to the skin of BALB/c mice. Representative sections of the dorsal skin from mice of both strains aged 18 days, and 1, 3, 6, and 8 months were studied. Sections stained with hematoxylin and eosin showed cystic formations called utricles and dermal cysts in the dermis that increased in size and number during growth. Skin thickness increased significantly at 8 months. Sections stained with picrosirius and examined with polarized light, displayed different colors, suggesting different thicknesses of dermal collagen fibers (probably types I and III). Weigert, Verhoeff and resorcin-fuchsin stains revealed fibers of the elastic system. The PAS and Alcian blue methods revealed neutral and acid glycosaminoglycans in the skin ground substance of both mouse strains. Immunohistochemical staining for fibronectin and laminin did not show differences between the mutant and BALB/c mice. Mast cells stained by the Gomori method and macrophages positive for HAM 56 antibodies were observed in both mouse strains. Except for the presence of enlarged cysts in the hairless strain, no qualitative differences were found during development of the skin of BALB/c and the mutant hairless mice.

Electrical parameters and water permeability properties of monolayers formed by T84 cells cultured on permeable supports

T84 is an established cell line expressing an enterocyte phenotype whose permeability properties have been widely explored. Osmotic permeability (P OSM), hydraulic permeability (P HYDR) and transport-associated net water fluxes (J W-transp), as well as short-circuit current (I SC), transepithelial resistance (R T), and potential difference (deltaV T) were measured in T84 monolayers with the following results: P OSM 1.3 ± 0.1 cm.s-1 x 10-3; P HYDR 0.27 ± 0.02 cm.s-1; R T 2426 ± 109 omega.cm², and deltaV T 1.31 ± 0.38 mV. The effect of 50 µM 5,6-dichloro-1-ethyl-1,3-dihydro-2H-benzimidazol-2-one (DCEBIO), a "net Cl- secretory agent", on T84 cells was also studied. We confirm the reported important increase in I SC induced by DCEBIO which was associated here with a modest secretory deltaJ W-transp. The present results were compared with those reported using the same experimental approach applied to established cell lines originating from intestinal and renal epithelial cells (Caco-2, LLC-PK1 and RCCD-1). No clear association between P HYDR and R T could be demonstrated and high P HYDR values were observed in an electrically tight epithelium, supporting the view that a "water leaky" barrier is not necessarily an "electrically leaky" one. Furthermore, the modest secretory deltaJ W-transp was not consistent with previous results obtained with RCCD-1 cells stimulated with vasopressin (absorptive fluxes) or with T84 cells secreting water under the action of Escherichia coli heat stable enterotoxin. We conclude that, while the presence of aquaporins is necessary to dissipate an external osmotic gradient, coupling between water and ion transport cannot be explained by a simple and common underlying mechanism.

An extract of Polygonum multiflorum protects against free radical damage induced by ultraviolet B irradiation of the skin

Over the last decades, the incidence of ultraviolet B (UVB)-related skin problems has been increasing. Damages induced by UVB radiation are related to mutations that occur as a result of direct DNA damage and/or the production of reactive oxygen species. We investigated the anti-oxidant effects of a Polygonum multiflorum thumb extract against skin damage induced by UVB irradiation. Female SKH-1 hairless mice were divided into three groups: control (N = 7), distilled water- (N = 10), and P. multiflorum extract-treated (PM, N = 10) groups. The PM (10 g) was extracted with 100 mL distilled water, cryo-dried and 9.8 g was obtained. The animals received a topical application of 500 µL distilled water or PM extract (1, 2, 4, 8, and 16%, w/v, dissolved in distilled water) for 30 min after UVB irradiation (wavelength 280-320 nm, 300 mJ/cm²; 3 min) of the dorsal kin for 14 days, and skin immunohistochemistry and Cu,Zn-superoxide dismutase (SOD1) activity were determined. SOD1 immunoreactivity, its protein levels and activities in the skin were significantly reduced by 70% in the distilled water-treated group after UVB irradiation compared to control. However, in the PM extract-treated groups, SOD1 immunoreactivity and its protein and activity levels increased in a dose-dependent manner (1-16%, w/v, PM extract) compared to the distilled water-treated group. SOD1 protein levels and activities in the groups treated with 8 and 16%, w/v, PM extract recovered to 80-90% of the control group levels after UVB. These results suggest that PM extract strongly inhibits the destruction of SOD1 by UV radiation and probably contains anti-skin photoaging agents.

Modifications of the sympathetic skin response in workers chronically exposed to lead

The long-term effects of low-level lead intoxication are not known. The sympathetic skin response (SSR) was evaluated in a group of 60 former workers of a primary lead smelter, located in Santo Amaro, BA, Brazil. The individuals participating in the study were submitted to a clinical-epidemiological evaluation including questions related to potential risk factors for intoxication, complaints related to peripheral nervous system (PNS) involvement, neurological clinical examination, and also to electromyography and nerve conduction studies and SSR evaluation. The sample consisted of 57 men and 3 women aged 34 to 69 years (mean ± SD: 46.8 ± 6.9). The neurophysiologic evaluation showed the presence of lumbosacral radiculopathy in one of the individuals (1.7%), axonal sensorimotor polyneuropathy in 2 (3.3%), and carpal tunnel syndrome in 6 (10%). SSR was abnormal or absent in 12 cases, representing 20% of the sample. More than half of the subjects (53.3%) reported a history of acute abdominal pain requiring hospitalization during the period of work at the plant. A history of acute palsy of radial and peroneal nerves was reported by about 16.7 and 8.3% of the individuals, respectively. Mean SSR amplitude did not differ significantly between patients presenting or not the various characteristics in the current neurological situation, except for diaphoresis. The results suggest that chronic lead intoxication induces PNS damage, particularly affecting unmyelinated small fibers. Further systematic study is needed to more precisely define the role of lead in inducing PNS injury.

Gut permeability to lactulose and mannitol differs in treated Crohn's disease and celiac disease patients and healthy subjects

The gut barrier monitors and protects the gastrointestinal tract from challenges such as microorganisms, toxins and proteins that could act as antigens. There is evidence that gut barrier dysfunction may act as a primary disease mechanism in intestinal disorders. The aim of the present study was to evaluate the barrier function towards sugars after the appropriate treatment of celiac disease and Crohn's disease patients and compare the results with those obtained with healthy subjects. Fifteen healthy volunteers, 22 celiac disease patients after 1 year of a gluten-free diet, and 31 Crohn's disease patients in remission were submitted to an intestinal permeability test with 6.0 g lactulose and 3.0 g mannitol. Six-hour urinary lactulose excretion in Crohn's disease patients was significantly higher than in both celiac disease patients (0.42 vs 0.15%) and healthy controls (0.42 vs 0.07%). Urinary lactulose excretion was significantly higher in celiac disease patients than in healthy controls (0.15 vs 0.07%). Urinary mannitol excretion in Crohn's disease patients was the same as healthy controls (21 vs 21%) and these values were significantly higher than in celiac disease patients (10.9%). The lactulose/mannitol ratio was significantly higher in Crohn's disease patients in comparison to celiac disease patients (0.021 vs 0.013) and healthy controls (0.021 vs 0.003) and this ratio was also significantly higher in celiac disease patients compared to healthy controls (0.013 vs 0.003). In spite of treatment, differences in sugar permeability were observed in both disease groups. These differences in the behavior of the sugar probes probably reflect different mechanisms for the alterations of intestinal permeability.