Mineralogical control on arsenic release during sediment-water interaction in abandoned mine wastes from the Argentina Puna.

The sulfide-rich residues of La Concordia mine, Argentina Puna, are accumulated in tailing dams that remained exposed to the weathering agents for almost 30years. In such period of time, a complex sequence of redox and dissolution/precipitation reactions occurred, leading to the gradual oxidation of the wastes and the formation of weathering profiles. The sources of arsenic in the wastes were analyzed by XRD and SEM/EDS analysis while a standardized sequential extraction procedure was followed to define solid As associations. In addition, the release of As during sediment-water interaction was analyzed in a period of 10months. The results indicate that primary As-bearing minerals are arsenian pyrite and polymetallic sulfides. As-jarosite and scarce arsenates are the only secondary As-bearing minerals identified by XRD and SEM/EDS. However, the rapid release (i.e., <1h) of arsenic from suspensions of the studied sediments in water, seems to be associated to the dissolution of highly soluble (hydrous)sulfates, as it was determined in samples of the efflorescences that cover the entire site. Contributions from the more abundant As-jarosite are also expected in longer periods of sediment-water interaction, due to its low rate of dissolution in acid and oxic conditions. Finally, near 30% of As remains adsorbed onto Fe (hydr)oxides thus representing a hazardous reservoir with the potential of mobilizing As into porewaters and streamwaters if the acidic and oxidizing conditions that predominate in the region are altered.

[Vaccination and immunization in healthcare workers, towards specific infections: measles, varicella, rubella and mumps. The experience in a hospital in Lombardy]. / Vaccinazioni e immunizzazione nel personale sanitario verso infezioni specifiche: morbillo, varicella, rosolia e parotite. L'esperienza di una Azienda Ospedaliera Lombarda.

Lombardy Region, with the Deliberation NoVIII (22-12-2005), about vaccinations in childrens and adults, suggest to offer to the healthcare workers (HCW) of 'Infectious diseases' and of 'Obstetrics and 'Pediatrics' Department, the vaccines for varicella and measles, mumps and rubella (MMR). We performed in 120 HCW of our hospital the dosage of antibodies versus these infectious diseases, in order to protect both workers and critical patients. The study results show that more than 80% of the HCW was immune to all the four infectious diseases. The percentage of immunisation to measles, varicella and rubella exceeded the 90%, while 87.5% of HCW was immune to mumps. We are going to offer the vaccine to the operators that are not immune, but we are also thinking about offer it to the HCW working with critical patient.

Evaluation of the BeTha gene 1 kit for the qualitative detection of the eight most common Mediterranean beta-thalassemia mutations.

We describe the evaluation of the Bio-Rad BeTha Gene 1 kit (Bio-Rad Laboratories, Hercules, CA), a DNA-probe assay designed for the qualitative determination of the eight most common Mediterranean beta-thalassemia mutations. The kit utilizes the principle of allele-specific oligonucleotide (ASO) hybridization. Following sample preparation and in vitro DNA amplification by the polymerase chain reaction (PCR), an allele-specific detection of the amplified products by a nonradioactive enzymatic assay is performed. Genomic DNA is prepared from an individual's whole blood with a DNA purification matrix. In a second step, the beta-globin gene is amplified in a multiplex PCR reaction containing four 5' biotinylated oligonucleotide primers. In a final step, an aliquot of the PCR reaction is first chemically denatured and then captured in two eight-well strips of a 96-well enzyme-linked immunosorbent assay (ELISA) plate by hybridization to an immobilized ASO probe. Each DNA sequence at each of the eight mutation sites is represented by one normal and one mutant ASO. During this capture/hybridization step, which is performed at 37 degrees C, only perfectly matched PCR products will be captured by an ASO. Subsequently, the allele-specific captured biotin-labeled PCR products are detected by a colorimetric enzymatic reaction. The system permits the detection of 16 beta-thalassemia alleles using a high-throughput format that can be automated easily. A clinical feasibility study was performed to evaluate the functionality (method comparison study, assay validity using samples previously collected and stored at various temperatures for different periods of time, interference on kit performance, and assay validity for prenatal diagnosis) and the usability (ease of use, sample throughput) of the kit. The analysis of 110 samples previously studied with reference methods showed 100% clinical sensitivity and specificity. We demonstrate here that the procedure not only increases the throughput of beta-thalassemia allele genotyping but also provides an accurate, rapid, reliable, and nonisotopic diagnostic tool.

Medication use and the risk of Stevens-Johnson syndrome or toxic epidermal necrolysis.

BACKGROUND: Toxic epidermal necrolysis and Stevens-Johnson syndrome are rare, life-threatening, drug-induced cutaneous reactions. We conducted a case-control study to quantify the risks associated with the use of specific drugs. METHODS: Data were obtained through surveillance networks in France, Germany, Italy, and Portugal. Drug use before the onset of disease was compared in 245 people who were hospitalized because of toxic epidermal necrolysis or Stevens-Johnson syndrome and 1147 patients hospitalized for other reasons (controls). Crude relative risks were calculated and adjusted for confounding by multivariate methods when numbers were large enough. RESULTS: Among drugs usually used for short periods, the risks were increased for trimethoprim-sulfamethoxazole and other sulfonamide antibiotics (crude relative risk, 172; 95 percent confidence interval, 75 to 396), chlormezanone (crude relative risk, 62; 21 to 188), aminopenicillins (multivariate relative risk, 6.7; 2.5 to 18), quinolones (multivariate relative risk, 10; 2.6 to 38), and cephalosporins (multivariate relative risk, 14; 3.2 to 59). For acetaminophen, the multivariate relative risk was 0.6 (95 percent confidence interval, 0.2 to 1.3) in France but 9.3 (3.9 to 22) in the other countries. Among drugs usually used for months or years, the increased risk was confined largely to the first two months of treatment, when crude relative risks were as follows: carbamazepine, 90 (95 percent confidence interval, 19 to infinity); phenobarbital, 45 (19 to 108); phenytoin, 53 (11 to infinity); valproic acid, 25 (4.3 to infinity); oxicam nonsteroidal antiinflammatory drugs (NSAIDs), 72 (25 to 209); allopurinol, 52 (16 to 167); and corticosteroids, 54 (23 to 124). For many drugs, including thiazide diuretics and oral hypoglycemic agents, there was no significant increase in risk. CONCLUSIONS: The use of antibacterial sulfonamides, anticonvulsant agents, oxicam NSAIDs, allopurinol, chlormezanone, and corticosteroids is associated with large increases in the risk of Stevens-Johnson syndrome or toxic epidermal necrolysis. But for none of the drugs does the excess risk exceed five cases per million users per week.

Combined Clark's nevus.

We report five cases of combined Clark's nevi. Like all melanocytic nevi, Clark's nevus can combine with other nevi to produce lesions that are hard to interpret clinically and histologically. The morphology of combined Clark's nevus can resemble that of a melanoma associated with a nevus.

Cutaneous malignant melanoma appearing during photochemotherapy of mycosis fungoides.

We report a case of malignant melanoma that appeared in a 56-year-old man with mycosis fungoides (stage Ia) during treatment with PUVA. The cumulative UVA dose was 1,177 J/cm2. The pigmented lesion was removed and PUVA therapy discontinued. Histological examination revealed a superficial spreading malignant melanoma (1.77 mm thick, Clark level IV). The delayed-type cutaneous hypersensitivity was studied. The presence of a second malignancy after mycosis fungoides and PUVA therapy may have been coincidental. Nevertheless, this case suggests that the immunosuppression induced by mycosis fungoides and by PUVA therapy might be a pathogenetic factor in the development of malignant melanoma.

Agminate blue nevus combined with lentigo. A variant of speckled lentiginous nevus?

We report a case of agminate blue nevus combined with a lentigo patch in a 38-year-old woman. The combination was interpreted as a unique and peculiar variant of speckled lentiginous nevus.

Cutaneous manifestations associated with antiphospholipid antibodies in patients with suspected primary antiphospholipid syndrome: a case-control study.

OBJECTIVE: To study the association of a variety of dermatological manifestations related to vascular abnormalities with antiphospholipid antibodies in patients with suspected primary antiphospholipid syndrome. METHOD: Case-control study. Consecutive patients referred to the coagulation and haemostasis service of a general hospital for the first determination of antiphospholipid antibodies (lupus anticoagulant and anticardiolipin antibodies) and newly diagnosed disorders (for example, thrombocytopenia, thrombotic disorders, and unexplained repeated abortions) were selected. Patients were examined by two dermatologists according to predefined criteria, and information about general characteristics and relevant dermatological and medical histories were collected using an ad hoc questionnaire. The study was limited to patients without evidence of systemic lupus erythematosus. A total of 35 patients was examined; 13 subjects were positive for lupus anticoagulant or anticardiolipin antibodies, or both (cases), and 22 were negative (controls). RESULTS: Moderate to severe livedo reticularis and acrocyanosis were significantly associated with antiphospholipid antibodies, with relative risks of 13.1 (95% confidence interval 1.1 to 149.0) and 8.6 (95% confidence interval 1.1 to 65.1). Capillaritis was also associated with the antibodies. Histories of Raynaud's phenomenon and superficial thrombophlebitis were more common in cases than controls. CONCLUSIONS: This study provides quantitative evidence of the association of antiphospholipid antibodies with several cutaneous diseases in which vascular abnormalities seem to play a major part. The study suggests that these manifestations might appear early in the development of the antiphospholipid syndrome.

Overproduction and functional analysis of DNA primase subunits from yeast and mouse.

Eukaryotic DNA primases are composed of two distinct subunits of 48-50 and 58-60 kDa. The amino acid sequences derived from the nucleotide sequences of the cloned genes are known only for the yeast and mouse polypeptides, and the extensive homology between the corresponding mouse and yeast subunits suggests conservation of functional domains. We were able to express in Saccharomyces cerevisiae the homologous and mouse primase-encoding genes under the control of both the constitutive ADH1 and the inducible GAL1 strong promoters, thus obtaining strains producing relevant amounts of the different polypeptides. In vivo complementation studies showed that neither one of the wild-type mouse primase-encoding genes was able to rescue the lethal or temperature-sensitive phenotype caused by mutations in the yeast PRI1 or PRI2 genes, indicating that these proteins, even if structurally and functionally very similar, might be involved in critical species-specific interactions during DNA replication.

Unusual manifestations of primary cutaneous amyloidosis in association with Raynaud's phenomenon and livedo reticularis.

A patient with unusual manifestations of primary cutaneous amyloidosis, including macules, papules, oedematous plaques and urticarial lesions is described. Raynaud's phenomenon and livedo reticularis were an associated finding. During the acute phase, single doses of systemic corticosteroids resulted in an impressive, long-lasting improvement in cutaneous manifestations.

[A comparison between amiodarone and disopyramide in a delayed-release formulation in the prevention of recurrences of symptomatic atrial fibrillation]. / Confronto fra amiodarone e disopiramide in formulazione retard nella prevenzione delle recidive di fibrillazione atriale sintomatica.

In order to compare the efficacy in preventing recurrencies of symptomatic atrial fibrillation of amiodarone (A.) and slow release disopyramide (D.RET.), 76 consecutive patients with recent onset atrial fibrillation (1 to 24 hrs.) were enrolled. In 20 (26%) conversion to sinus rhythm was obtained by electrical cardioversion, and in 56 (74%) by oral quinidine loading. Forty-one patients (group A) were assigned at random to treatment with D.RET. (250 mg twice daily) and 35 patients (group B) to amiodarone treatment (1200 mg daily for 10 days, and subsequently 200 mg daily). The two groups were similar as to age, sex and cardiac pathology. Patients were followed as to clinical condition, standard and dynamic ECG after one and three months and every three months subsequently for an average of 13.2 months (group A) and 14.1 months (group B). Six group A patients (14%) were excluded from follow-up on account of side effects which arose during the first week of treatment. Crises of symptomatic atrial fibrillation occurred in 20 patients of group A (57%) and in 11 (32%) group patients; this difference is statistically significant (p less than 0.05). Four (10%) group A patients stopped taking the drug due to side effects of an anticholinergic type, and three (8.5%) patients developed hyperthyroidism during follow-up. The authors therefore come to the conclusion that amiodarone is more effective than slow-release disopyramide in preventing recurrencies of atrial fibrillation; besides untoward side effects are less frequent with amiodarone.

Role of pump-induced dispersion on femtosecond soliton amplification in erbium-doped fibers.

The limitation to the amplification of femtosecond pulses by erbium-doped fibers owing to the soliton self-frequency shift may be overcome by using a dispersion-shifted fiber. We show that this result holds irrespective of the relatively large residual frequency-dependent chromatic dispersion that is associated with the pumping of the doping ions. Nevertheless, resonant dispersion may lead to temporal broadening and distortion of the amplified pulse.

Adiabatic femtosecond soliton active nonlinear directional coupler.

The optimal all-optical switching, amplification, and temporal compression of femtosecond solitons by means of a nonlinear erbium-doped twin-core fiber may be achieved by suitably tapering the linear coupling strength. We analytically show that, irrespective of the soliton self-frequency shift, tapering may in principle reduce the switching power threshold to arbitrarily low values. A substantial reduction is also demonstrated in a practical case in which the full complex susceptibility of the erbium doping and the Raman response function are considered.