Electrochemical aptasensors for contaminants detection in food and environment: Recent advances.

The growing number of contaminants requires the development of new analytical tools to meet the increasing demand for legislative actions on food safety and environmental pollution control. In this context, electrochemical aptamer-based sensors appear promising among all biosensors because they permit multiplexed analysis and provide fast response, sensitivity, specificity and low cost. The aim of this review is to give the readers an overview of recent important achievements in the development of electrochemical aptamer-based biosensors for contaminant detection over the last two years. Special emphasis is placed on aptasensors based on screen-printed electrodes which show a substantial improvement of analytical performances.

Acetamiprid multidetection by disposable electrochemical DNA aptasensor.

In this work, we propose an electrochemical DNA aptasensor for sensitive multidetection of acetamiprid based on a competitive format and disposable screen-printed arrays. To improve the sensitivity of the aptasensor, polyaniline film and gold nanoparticles were progressively electrodeposited on the graphite screen-printed electrode surface by cyclic voltammetry. Gold nanoparticles were then employed as platform for thiol-tethered DNA aptamer immobilization. Different acetamiprid solutions containing a fixed amount of biotinylated complementary oligonucleotide sequence by DNA aptasensor arrays were analyzed. Streptavidin-alkaline phosphatase conjugate was then added to trace the affinity reaction. The enzyme catalyzed the hydrolysis of 1-naphthyl phosphate to 1-naphthol. The enzymatic product was detected by differential pulse voltammetry. A decrease of the signal was obtained when the pesticide concentration was increased, making the sensor work as signal off sensor. Under optimized conditions by testing key experimental parameters, a dose-response curve was constructed between 0.25 and 2.0µM acetamiprid concentration range and a limit of detection of 0.086µM was calculated. The selectivity of the aptasensor was also confirmed by the analysis of atrazine pesticide. Finally, preliminary experiments in fruit juice samples spiked with acetamiprid were also performed.

Buschke-Ollendorff syndrome associated with elevated elastin production by affected skin fibroblasts in culture.

Buschke-Ollendorff syndrome (BOS; McKusick 16670) is an autosomal dominant connective-tissue disorder characterized by uneven osseous formation in bone (osteopoikilosis) and fibrous skin papules (dermatofibrosis lenticularis disseminata). We describe two patients in whom BOS occurred in an autosomal dominant inheritance pattern. The connective tissue of the skin lesions showed both collagen and elastin abnormalities by electron microscopy. Cultured fibroblasts from both patients produced 2-8 times more tropoelastin than normal skin fibroblasts in the presence of 10% calf serum. Involved skin fibroblasts of one patient produced up to eight times normal levels, whereas apparently uninvolved skin was also elevated more than threefold. In a second patient, whose involvement was nearly complete, elastin production was high in involved areas and less so in completely involved skin. Transforming growth factor-beta 1 (TGF beta 1), a powerful stimulus for elastin production, brought about similar relative increases in normal and BOS strains. Basic fibroblast growth factor, an antagonist of TGF beta 1-stimulated elastin production, was able to reduce elastin production in basal and TGF beta 1 stimulated BOS strains. Elastin mRNA levels were elevated in all patient strains, suggesting that Buschke-Ollendorff syndrome may result, at least in part, from abnormal regulation of extracellular matrix metabolism that leads to increased steady-state levels of elastin mRNA and elastin accumulation in the dermis.

Keratinocyte transglutaminase expression varies in squamous cell carcinomas.

Type I transglutaminase (TGase I, keratinocyte or particulate transglutaminase) is a 92-kilodalton (kDa) protein expressed in abundance in cultured keratinocytes and in the hyperproliferative skin disorder psoriasis. To determine the expression of TGase I protein and mRNA, we studied tissue and established squamous carcinoma lines derived from different sources. Immunohistochemistry and Western blotting were used to detect TGase I protein with the B.C1 mouse monoclonal antibody. Only well-differentiated, skin-derived squamous carcinomas stained for TGase I. However, a precocious pattern of expression was seen overlying less-differentiated tumors. Compared to cultured human keratinocytes, squamous cell carcinoma (SCC) had many times less to 7.8 times more TGase I protein, greatest in the two most differentiated tumor lines 14-83 and ME-180. TGase I mRNA levels ranged from 0.010 to 0.00004 pg/microgram total RNA by reverse transcriptase-polymerase chain reaction using an internal standard. Protein expression correlated with mRNA levels in most SCC lines. When a human TGase I promoter was isolated and used to study genomic DNA, SCC1-83 was shown to have unique restriction enzyme fragments, including one indicative of methylation differences, also present within DNA from the KB line. These studies suggest that transcriptional control of TGase I gene expression in squamous carcinomas may be influenced both by cis elements in the promoter and by the degree of tumor squamous differentiation.

Skin lesions of the spinal axis and spinal dysraphism. Fifteen cases and a review of the literature.

OBJECTIVE: To catalog the paraspinal skin lesions of early childhood that are associated with occult spinal dysraphism. RESEARCH DESIGN: Retrospective review of a series of patients. SETTING: Tertiary care referral center. PATIENTS: Fifteen patients who had significant paraspinal skin lesions were identified from the personal files of the authors who saw them. RESULTS: The skin lesions included various combinations of hyperpigmentation, hypopigmentation, hypertrichosis, acrochordons, dimples, lipomas, hemangiomas, or teratomas. Not all lesions were evaluated with the same tests, which included plain roentgenography, ultrasonography, myelography, computed tomography, and magnetic resonance imaging. Of the 15 patients, six had spinal anomalies, eight had no apparent spinal dysraphism, and one had insufficient results of the evaluation to assess the spinal column. CONCLUSIONS: Early recognition of paraspinal skin lesions is essential to prevent neurologic damage. Urinary or fecal incontinence, recurrent urinary infections, muscle atrophy, foot deformities, weakness, pain, or decreased sensation in the lower extremities may eventually develop in these patients. Magnetic resonance imaging appears to be the single best screening test for dysraphism.

Oral lesions in pityriasis rosea.

Oral lesions are not commonly reported with pityriasis rosea (PR). We encountered a patient with clinical and histologic evidence of PR who developed aphthous ulcer-like oral lesions on the buccal mucosa, palate, and tongue. The oral lesions resolved concomitantly with the patient's skin lesions. The previous literature reports a wide variety of oral lesions in association with PR, but few dermatologists, to our knowledge, are aware of such an occurrence.

Acquired perforating dermatosis. Evidence for combined transepidermal elimination of both collagen and elastic fibers.

Patients with renal disease or diabetes mellitus often have an acquired perforating disease of the skin develop that is characterized by hyperkeratotic papules with transepidermal elimination of degenerated material, including collagen or elastic fibers. There is disagreement regarding the most appropriate name for this disease. The pathologic process has been identified by various authors as reactive perforating collagenosis, elastosis perforans serpiginosa, perforating folliculitis, or Kyrle's disease. We have seen four patients with renal disease and/or diabetes whose skin biopsy specimens demonstrated combined transepidermal elimination of both collagen and elastic fibers. This finding is not characteristically seen in any of the previously defined perforating diseases. Since the histologic findings vary greatly in different lesions from different patients with renal disease, we recommend referring to this process as "acquired perforating dermatosis." It is best not to create a new category of perforating disease or to say that a given patient has one of the other four diseases based on random sampling of only a few lesions.

Acquired immunodeficiency syndrome-associated psoriasis and Reiter's syndrome.

Human immunodeficiency virus (HIV) causes a spectrum of immunodysfunction, the most severe of which is the acquired immunodeficiency syndrome (AIDS). We have followed the course of psoriasis in 13 patients over 2 1/2 years in a population of more than 1000 HIV-positive individuals. Four patients had a history of mild psoriasis that became severe and uncontrollable as symptoms of immunodeficiency developed. Psoriasis and HIV positivity, AIDS-related complex, or AIDS simultaneously developed in nine patients. In addition to psoriasis, Reiter's syndrome (arthritis, urethritis, and conjunctivitis) developed in one patient in the first group and three patients in the second group. Opportunistic infections, especially candidiasis and Staphylococcus, drugs, and an altered immune system may contribute to the development or flare of psoriasis in these patients. The appearance of severe psoriasis (especially in a patient with other risk factors for HIV) should prompt evaluation for HIV, and may be a poor prognostic indicator in HIV-positive patients, since nine of our 13 patients have died. Immunosuppressive therapy with methotrexate is contraindicated in this group of patients. Newer forms of drug therapy including etretinate show promising results for the management of AIDS-associated psoriasis.

Glucan-induced keratoderma in acquired immunodeficiency syndrome.

Six of 20 patients with acquired immunodeficiency syndrome (AIDS) or AIDS-related complex receiving intravenous infusions of soluble glucan (beta-1-3 polyglucose) developed a keratoderma of the palms and soles. The eruption began during the first two weeks of therapy and resolved two to four weeks after its discontinuation. The eruption was different in appearance from our previously reported keratoderma blennorrhagica in AIDS-associated psoriasis. None of the other 735 patients with AIDS or AIDS-related complex not treated with soluble glucan developed a similar keratoderma. The correlation between receiving glucan and the hyperkeratosis is highly significant. Since glucan is a naturally occurring component of the cell walls of yeast, fungus, and some bacterial organisms, recognition of its ability to induce such a striking reaction pattern may be of general significance and interest, although the reaction itself may be limited to patients with AIDS.

Eruptive dysplastic nevi associated with human immunodeficiency virus infection.

The cutaneous manifestations of the acquired immunodeficiency syndrome include infections and neoplasms resulting from the immunodeficient state. Seven patients presenting with the symptom of new eruptive nevi with dysplastic histologic findings are described. These patients noted multiple new moles, which occurred in crops and in individuals without the dysplastic nevus syndrome (familial melanomas). This symptom occurred as the patients became symptomatic from their human immunodeficiency virus infection, developing acquired immunodeficiency syndrome or its related complex. Further confirmation and study of this phenomenon could lead to a better understanding of the pathogenesis of melanocytic dysplasia and its relationship to the immune system.

Treatment of cutaneous squamous cell carcinomas by intralesional interferon alfa-2b therapy.

BACKGROUND AND DESIGN: Intralesional recombinant interferon alfa-2b has been shown to be effective in the treatment of actinic keratoses and basal cell carcinomas. This open-label study was designed to evaluate the effectiveness and cosmetic result of this therapy on actinically induced, primary cutaneous squamous cell carcinomas. Thirty-six squamous cell carcinomas (28 invasive lesions and 8 in situ lesions) ranging in size from 0.5 to 2.0 cm in the longest dimension were treated with interferon alfa-2b 1.5 million units injected intralesionally three times per week for 3 weeks. Eighteen weeks following therapy, the treatment sites were excised and examined for histologic evidence of remaining tumor. RESULTS: Thirty-three (97.1%) of 34 evaluable lesions revealed an absence of squamous cell carcinoma histologically after therapy, although three biopsy specimens (8.8%) obtained after treatment showed actinic keratoses, for an overall complete response rate of 88.2%. The lesion not eliminated after treatment was an invasive squamous cell carcinoma. The investigators and patients independently judged 93.9% of cases to have a very good or excellent cosmetic result. Adverse reactions were limited to those influenzalike symptoms well recognized to occur with interferon therapy and these were well tolerated. Only one patient discontinued therapy due to side effects. CONCLUSIONS: This trial demonstrates that intralesional interferon is effective in the treatment of small sun-induced squamous cell carcinomas with well-tolerated side effects and a highly acceptable cosmetic result.

Obtaining a skin biopsy specimen and interpreting the results.

Skin biopsy specimens are interpreted by general pathologists and dermatologists, as well as by devoted dermatopathologists. Pitfalls of obtaining the biopsy specimen, grossing the specimen, evaluating the sections, and reporting the results are discussed on an advanced level. Controversial economic issues and government regulations are tackled, with respect to how they affect the final result. Last, several stereotypes of prototypical dermatologic surgeons and dermatopathologists are used to illustrate how practice patterns affect the accuracy of subjective skin biopsy specimen reports.

Malignancy in Maffucci's syndrome.

Maffucci's syndrome is characterized by multiple enchondromas and subcutaneous hemangiomas. These tumors typically present in early childhood and may lead to significant skeletal deformities. Malignant transformations are a common feature of this syndrome and have been reported in approximately 30% of reported cases, with chondrosarcomas being the most common.

Dermatopathologic advances in clinical research. The expression of antibody to CD34 in mucocutaneous lesions. off.

The human progenitor cell antigen, CD34, is selectively expressed in most hematopoietic colony-forming cells from normal human bone marrow, and in a significant proportion of acute leukemias. Within the dermis, CD34 is normally expressed by endothelial cells, dendritic cells, and the spindle-shaped cells around adnexal structures. Benign and malignant vascular lesions, adnexal tumors differentiating toward the external root sheath (trichilemmomas and pilar tumors), specific benign soft tissue tumors (spindle cell lipoma and solitary fibrous tumors), and many of the gastrointestinal stromal tumors uniformly express CD34 antigen. CD34 expression is also often present in benign tumors of neural origin; however, it is less consistently present in malignant peripheral nerve sheath tumors.

Oral melanoma: diagnosis and treatment.

Melanoma of the mouth is rare, most commonly occurring on the upper jaw of patients older than 50 years. Because of a frequent delay in diagnosis, the tumors are often diagnosed after they are deeper than the average cutaneous melanoma. Hence, the prognosis tends to be poor. Surgery is the mainstay of treatment, but often it is difficult because of anatomic restraints. Although melanoma is classically not very radiosensitive, occasional patients have had a good response to radiation therapy, sometimes with temporary palliation. Other treatment modalities are similar to those used for cutaneous melanoma. Immunotherapy, including interferon, has been used. Chemotherapy has a low response rate.

Spitz nevus or melanoma?

Spitz nevi are benign melanocytic neoplasms of children and young adults that can be exceedingly difficult to distinguish from malignant melanomas. Although a nearly definite diagnosis can be made in most cases, the histological distinction between Spitz nevi and melanomas is equivocal in about 6% to 8% of cases. In those cases, and perhaps even with presumed benign Spitz nevi, clear surgical margins are desirable. The most helpful differentiating features of Spitz nevi are patient age, sharp demarcation, symmetry, maturation of melanocytes at the base, and epithelial hyperplasia. None of these criteria are completely reliable, and multiple other criteria must be considered as well.

Practical evaluation of skin lesions in immunosuppressed patients.

Physicians today are seeing many more immunosuppressed patients because of the prevalence of infection with the human immunodeficiency virus, use of chemotherapy for malignancies, and immunosuppressive therapy for patients undergoing organ transplantation. This paper gives many practical tips for the evaluation of skin lesions in these patients. Banal-appearing skin lesions in immunosuppressed patients may represent an unusual infection, a malignancy, or a reactive process. Even common disorders may produce unusual manifestations in such patients. The astute clinician will constantly be alert to the possibilities of combined infections or drug-related eruptions, and will investigate the possibility of an infectious process in patients who appear to have vasculitis or panniculitis.

Transient acantholytic dermatosis in patients with cancer.

Nine patients with transient acantholytic dermatosis were seen at a hospital treating patients with cancer within less than two years. This common disorder seemed to be related to heat, fever, sweating, and bed rest, and it is important to differentiate it from a drug-induced rash.

Psoriasiform eruption from intramuscular botulinum A toxin.

Botulinum A toxin is used intramuscularly in the treatment of spastic neuromuscular disorders, strabismus, and laryngeal dystonia. The toxin has recently been reported as being useful for the cosmetic removal of glabellar furrows. The clinical effect of the toxin lasts four months or longer. Systemic side effects are rare and usually transient. We report the case of a psoriasiform eruption temporally related to the injection of botulinum A toxin into the medial rectus muscle to treat an ocular motility disorder. To our knowledge, this is the first case of a psoriasiform dermatitis caused by this agent.