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Elevated leaf silicon (Si) concentrations improve drought resistance in cultivated plants, suggesting Si might also improve drought performance of wild species. Tropical tree species, for instance, take up substantial amounts of Si, and leaf Si varies markedly at local and regional scales, suggesting consequences for seedling drought resistance. Yet, whether elevated leaf Si improves seedling drought performance in tropical forests is unknown. To manipulate leaf Si concentrations, seedlings of seven tropical tree species were grown in Si-rich and -poor soil, before exposing them to drought in the forest understorey. Survival, growth and wilting were monitored. Elevated leaf Si did not improve drought survival and growth in any of the species. In one species, drought survival was reduced in seedlings previously grown in Si-rich soil, contrary to our expectation. Our results suggest that elevated leaf Si does not improve drought resistance of wild tropical tree species. Elevated leaf Si may even reduce drought performance, suggesting differences in soil conditions influencing leaf Si may contribute to soil-related variation of tropical seedling performance. Furthermore, our results are at odds with most studies on cultivated species and show that alleviative effects of Si in crops cannot be generalized to wild plants in natural systems.

In flooded paddy soils, inorganic and methylated thioarsenates contribute substantially to arsenic speciation besides the much-better-investigated oxyarsenic species, and thioarsenate uptake into rice plants has recently been shown. To better understand their fate when soil redox conditions change, that is, from flooding to drainage to reflooding, batch incubations and unplanted microcosm experiments were conducted with two paddy soils covering redox potentials from EH−260 to +200 mV. Further, occurrence of thioarsenates in the oxygenated rice rhizosphere was investigated using planted rhizobox experiments. Soil flooding resulted in rapid formation of inorganic thioarsenates with a dominance of trithioarsenate. Maximum thiolation of inorganic oxyarsenic species was 57% at EH−130 mV and oxidation caused nearly complete dethiolation. Only monothioarsenate formed again upon reflooding and was the major inorganic thioarsenate detected in the rhizosphere. Maximum thiolation of mono- and dimethylated oxyarsenates was about 70% and 100%, respectively, below EH0 mV. Dithiolated species dominated over monothiolated species below EH−100 mV. Among all thioarsenates, dimethylated monothioarsenate showed the least transformation upon prolonged oxidation. It also was the major thiolated arsenic species in the rhizosphere with concentrations comparable to its precursor dimethylated oxyarsenate, which is especially critical since dimethylated monothioarsenate is highly carcinogenic.

In most natural groundwaters, sulfide concentrations are low, and little attention has been paid to potential occurrence of thioarsenates (AsVSn–IIO4–n3–with n= 1–4). Thioarsenate occurrence in groundwater could be critical with regard to the efficiency of iron (Fe)-based treatment technologies because previous studies reported less sorption of thioarsenates to preformed Fe-minerals compared to arsenite and arsenate. We analyzed 273 groundwater samples taken from different wells in Bangladesh over 1 year and detected monothioarsenate (MTA), likely formed via solid-phase zero-valent sulfur, in almost 50% of all samples. Concentrations ranged up to >30 μg L–1(21% of total As). MTA removal by locally used technologies in which zero-valent or ferrous Fe is oxidized by aeration and As sorbs or coprecipitates with the forming Fe(III)hydroxides was indeed lower than for arsenate. The presence of phosphate required up to three times as much Fe(II) for comparable MTA removal. However, in contrast to previous sorption studies on preformed Fe minerals, MTA removal, even in the presence of phosphate, was still higher than that of arsenite. The more efficient MTA removal is likely caused by a combination of coprecipitation and adsorption rendering the tested Fe-based treatment technologies suitable for As removal also in the presence of MTA.

Atypical fibroxanthomas and pleomorphic dermal sarcomas are tumors arising in sun-damaged skin of elderly patients. They have differing prognoses and are currently distinguished using histological criteria, such as invasion of deeper tissue structures, necrosis and lymphovascular or perineural invasion. To investigate the as-yet poorly understood genetics of these tumors, 41 atypical fibroxanthomas and 40 pleomorphic dermal sarcomas were subjected to targeted next-generation sequencing approaches as well as DNA copy number analysis by comparative genomic hybridization. In an analysis of the entire coding region of 341 oncogenes and tumor suppressor genes in 13 atypical fibroxanthomas using an established hybridization-based next-generation sequencing approach, we found that these tumors harbor a large number of mutations. Gene alterations were identified in more than half of the analyzed samples in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERTpromoter. The presence of these alterations was verified in 26 atypical fibroxanthoma and 35 pleomorphic dermal sarcoma samples by targeted amplicon-based next-generation sequencing. Similar mutation profiles in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERTpromoter were identified in both atypical fibroxanthoma and pleomorphic dermal sarcoma. Activating RASmutations (G12 and G13) identified in 3 pleomorphic dermal sarcoma were not found in atypical fibroxanthoma. Comprehensive DNA copy number analysis demonstrated a wide array of different copy number gains and losses, with similar profiles in atypical fibroxanthoma and pleomorphic dermal sarcoma. In summary, atypical fibroxanthoma and pleomorphic dermal sarcoma are highly mutated tumors with recurrent mutations in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERTpromoter, and a range of DNA copy number alterations. These findings suggest that atypical fibroxanthomas and pleomorphic dermal sarcomas are genetically related, potentially representing two ends of a common tumor spectrum and distinguishing these entities is at present still best performed using histological criteria.

Atypical fibroxanthomas and pleomorphic dermal sarcomas are tumors arising in sun-damaged skin of elderly patients. They have differing prognoses and are currently distinguished using histological criteria, such as invasion of deeper tissue structures, necrosis and lymphovascular or perineural invasion. To investigate the as-yet poorly understood genetics of these tumors, 41 atypical fibroxanthomas and 40 pleomorphic dermal sarcomas were subjected to targeted next-generation sequencing approaches as well as DNA copy number analysis by comparative genomic hybridization. In an analysis of the entire coding region of 341 oncogenes and tumor suppressor genes in 13 atypical fibroxanthomas using an established hybridization-based next-generation sequencing approach, we found that these tumors harbor a large number of mutations. Gene alterations were identified in more than half of the analyzed samples in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter. The presence of these alterations was verified in 26 atypical fibroxanthoma and 35 pleomorphic dermal sarcoma samples by targeted amplicon-based next-generation sequencing. Similar mutation profiles in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter were identified in both atypical fibroxanthoma and pleomorphic dermal sarcoma. Activating RAS mutations (G12 and G13) identified in 3 pleomorphic dermal sarcoma were not found in atypical fibroxanthoma. Comprehensive DNA copy number analysis demonstrated a wide array of different copy number gains and losses, with similar profiles in atypical fibroxanthoma and pleomorphic dermal sarcoma. In summary, atypical fibroxanthoma and pleomorphic dermal sarcoma are highly mutated tumors with recurrent mutations in FAT1, NOTCH1/2, CDKN2A, TP53, and the TERT promoter, and a range of DNA copy number alterations. These findings suggest that atypical fibroxanthomas and pleomorphic dermal sarcomas are genetically related, potentially representing two ends of a common tumor spectrum and distinguishing these entities is at present still best performed using histological criteria.

The overlap of Erdheim–Chester disease (ECD) and Langerhans cell histiocytosis (LCH) is more common than it was generally accepted. Both diseases seem to be linked by a mutation in oncogenic BRAFV600E, probably an early event which occurs in bone marrow progenitor cells. In this article are described the clinical and histological findings in 2 cases of ECD-LCH overlap syndrome bearing the BRAFV600E mutation in both ECD and LCH lesions in bone and skin. In one case, lesions of ECD and LCH were situated directly site-to-site in the same bone section leading to the assumption of a common myeloid precursor cell for these diseases. Furthermore, we focus on the histopathological diagnostic criteria of cutaneous involvement in ECD. Lesional tissue shows a dermal infiltrate of lipidized CD68+, CD163+, CD1a−, and langerin histiocytes admixed with Touton giant cells—a xanthogranulomatous phenotype. Often, this pattern of histopathology requires correlation with patterns of systemic involvement to differentiate ECD from other xanthogranulomatous infiltrates. This endeavor is of major importance to determine early diagnosis and treatment, because ECD often shows a poor prognosis compared with its differential diagnoses. Finally, adults who suffer from LCH and develop xanthogranulomatous infiltrates should always be screened for ECD-LCH overlap syndrome.

Supplemental Digital Content is Available in the Text.Inflammatory and subcutaneous nodules can arise in treated and untreated cases of Whipple disease (WD). The inflammatory immune reconstitution syndrome describes paradoxical clinical inflammatory worsening of a preexisting condition because of a return of immune function. Clinicopathologic examination of 4 patients with WD who presented with erythema nodosum leprosum (ENL)–like lesions and the findings of a systematic review of this phenomenon revealed that ENL-like lesions occurred in predominantly middle-aged male patients who suffered from WD, mostly on the legs. Patients showed a nonvasculitic, mostly septal panniculits with neutrophils, macrophages, and lymphocytes. Numerous bacteria-laden periodic acid–Schiff + macrophages and free bacilli were detected in the dermis, as well as subcutaneous septae and adipose lobules. These lesions occurred in both untreated and treated patients as part of inflammatory immune reconstitution syndrome. In conclusion, ENL-like lesions represent a characteristic histopathologic pattern associated with WD, which can occur in different contexts whenever there is a change in the immunological status of the patient. This change can be triggered by antimicrobial treatment, immunomodulatory and immunosuppressant therapy, or occur spontaneously, rarely.

Activating mutations in the TERT promoter leading to increased telomerase expression were recently identified in cutaneous melanoma and subsequently in many other types of cancer. These mutations lead to increased telomerase expression, allowing cells to proliferate continuously without entering apoptosis or senescence. Atypical fibroxanthomas and pleomorphic dermal sarcomas are genetically poorly understood tumors developing in the skin of older patients. Known genetic events in these tumors are mutations in TP53 (atypical fibroxanthoma and pleomorphic dermal sarcoma) and RAS (pleomorphic dermal sarcoma) genes, often having a UV signature. We analyzed a cohort of 27 atypical fibroxanthomas and 34 pleomorphic dermal sarcomas for the presence of TERT promoter mutations by conventional Sanger sequencing. TERT promoter mutations were identified in 25 (93%) atypical fibroxanthomas and in 26 (76%) pleomorphic dermal sarcomas. Mutations were found to have a UV signature (C>T or CC>TT) and were largely identical to those detected in cutaneous melanoma. Our data show that TERT promoter mutations are the most frequent mutations in atypical fibroxanthomas and pleomorphic dermal sarcomas reported to date. The identified mutations confirm the pathogenetic role of UV exposure in both atypical fibroxanthomas and pleomorphic dermal sarcomas and suggest that telomere maintenance through increased expression of telomerase plays an important role in the pathogenesis of these tumors.

Activating mutations in the TERTpromoter leading to increased telomerase expression were recently identified in cutaneous melanoma and subsequently in many other types of cancer. These mutations lead to increased telomerase expression, allowing cells to proliferate continuously without entering apoptosis or senescence. Atypical fibroxanthomas and pleomorphic dermal sarcomas are genetically poorly understood tumors developing in the skin of older patients. Known genetic events in these tumors are mutations in TP53(atypical fibroxanthoma and pleomorphic dermal sarcoma) and RAS(pleomorphic dermal sarcoma) genes, often having a UV signature. We analyzed a cohort of 27 atypical fibroxanthomas and 34 pleomorphic dermal sarcomas for the presence of TERTpromoter mutations by conventional Sanger sequencing. TERTpromoter mutations were identified in 25 (93%) atypical fibroxanthomas and in 26 (76%) pleomorphic dermal sarcomas. Mutations were found to have a UV signature (C>T or CC>TT) and were largely identical to those detected in cutaneous melanoma. Our data show that TERTpromoter mutations are the most frequent mutations in atypical fibroxanthomas and pleomorphic dermal sarcomas reported to date. The identified mutations confirm the pathogenetic role of UV exposure in both atypical fibroxanthomas and pleomorphic dermal sarcomas and suggest that telomere maintenance through increased expression of telomerase plays an important role in the pathogenesis of these tumors.

The decomposition process of plant litter is very important for carbon turnover. Much is known about the impact of invertebrate shredders on this process, but the effect of invertebrate grazers (e.g. detritivore freshwater snails) on litter processing has received little attention. These grazers are quite prevalent in some aquatic ecosystems. Therefore, a laboratory batch experiment was conducted to assess the effect of invertebrate grazers (aquatic snails) on aquatic litter decomposition and nutrient mobilization. Litter containing different amounts of silicon was used because silicon content is known to affect grazers. Invertebrate grazers had a significant effect on litter decomposition, increasing leaf mass loss by 100 % and reducing the cellulose content by 25 %. The leaf litter silicon content had no effect on these grazers. Furthermore, litter silicon content showed strong negative effects on nutrient remobilization, whereas the mobilization of calcium, nitrogen and DOC was affected by the invertebrates. It could be concluded that invertebrate grazer may have an important role in aquatic litter decomposition by decreasing litter cellulose content and enhancing mobilization of nutrients.

BACKGROUND IgA pemphigus is a rare neutrophilic acantholytic autoimmune disease that is characterized by IgA deposits on keratinocyte cell surfaces. Clinically and histologically, IgA pemphigus is divided into 2 major subtypes: subcorneal pustular dermatosis and intraepidermal neutrophilic IgA dermatosis. We report the first case of subcorneal pustular dermatosis–type IgA pemphigus that showed reactivity to all 3 isoforms of the desmocollin family by indirect immunofluorescence microscopy of COS7 cells transfected with desmocollin 1, 2, or 3. OBSERVATIONS We describe a 94-year-old woman with IgA pemphigus with a unique immunopathologic pattern. Direct immunofluorescence microscopy revealed IgA deposits throughout the entire epidermis, with stronger staining in the upper epidermis. The autoantibodies from this patient did not show IgA or IgG reactivity with desmogleins via immunoblotting or enzyme-linked immunosorbent assay. By indirect immunofluorescence by the use of COS7 cells transfected with desmocollin 1, 2, or 3, IgA autoantibodies in a serum sample from our patient clearly reacted with all of them. CONCLUSIONS The pathophysiology and autoantigen profile of bullous autoimmune diseases, especially pemphigus and its subforms, are more complex than previously believed. Because pemphigus seems to be a heterogeneous disorder, further studies are needed to evaluate the complexity of the disease.Arch Dermatol. 2009;145(10):1159-1162--

Mycosis fungoides is the most common type of cutaneous T-cell lymphoma, which is usually observed in mid to late adulthood. We report 5 cases of mycosis fungoides in children, all presenting as patch- and plaque-stage disease most commonly involving the buttocks. Histologic examination showed in every case the typical features of mycosis fungoides. In 4 of the 5 cases, the infiltrating lymphocytes were characterized by the T-cell phenotype CD3+, CD4+, CD8+; and in 3 cases, a monoclonal rearrangement of the T-cell receptor gamma (TCR-γ) gene was found. Three children received topical PUVA treatment, and the other two were treated with mid-potency topical corticosteroids, resulting in complete clinical remission. A management approach to mycosis fungoides with topical PUVA may be appropriate for children. (J Am Acad Dermatol 2002;47:557-61.)

Paraffin sections of 11 formalin‐fixed trichilemmomas were investigated for the presence of human papillomavirus (HPV) DNA by the polymerase chain reaction (PCR) with the degenerated consensus primer pairs. PCRs were conducted with different annealing temperatures. When the annealing temperature was reduced from 55°C to 50°C, amplification products of the expected size were obtained for all 11 cases investigated. Determination of the HPV type was performed by cloning and sequencing of the amplification products.

Der Schaufelsen bildet das größte zusammenhängende Felsmassiv ("Massenkalke") im Oberen Donautal; er wurde anhand eines ca. 84 m mächtigen Profils mit statistischer Beprobung untersucht. Ziel war es, den ungegliedert wirkenden Bereich (Malm delta4 und epsilon) im Hangenden der Glaukonitbank (Grenze Malm delta3/4) im Hinblick auf Mikrofazies und Diagenese zu untersuchen, um so zu Aussagen über den Bildungsraum des Massenkalkes zu gelangen. Komponenten und diagenetische Merkmale der Karbonatgesteine wurden anhand von Folienabzügen und Dünnschliffen analysiert. Die mineralogische Zusammensetzung der Gesteine (Calcit, Dolomit, Nichtkarbonate, Tonminerale) wurde röntgenographisch ermittelt. Die sehr reinen, grauweißen Kalke (96-100% CaCO3) des untersuchten Profils können aufgrund der Verteilung der vier Hauptkomponenten (Cyanobakterien-Krusten, Schwämme, Peloide, Ooide) sowie untergeordneter Komponenten (Intraklasten, andere Biogene) in fünf Faziestypen untergliedert werden, die sich vertikal in wechselnden Häufigkeiten unregelmäßig wiederholen. Eine geordnete vertikale Schichtfolge, die z. B. die verschiedenen Zonen eines Biohermwachstums widerspiegeln würde, ist nicht vorhanden. Aufgrund der Komponentenverteilung können drei große, sich überlagernde Fazieseinheiten erkannt werden, die sich auch in der morphologischen Ausbildung der Wände des Schaufelsen wieder erkennen lassen und die vom Liegenden zum Hangenden eine Verflachung des Ablagerungsraumes anzeigen. Die liegende Einheit-A, die oberhalb der Glaukonitbank beginnt, besteht aus Schwamm-führenden Peloid Wackestones und Packstones (lokal Grainstones) und weist eine Mächtigkeit von etwa 20 m auf. Die mittlere Einheit-B ist vorwiegend aus Ooid-Peloid Packstones-Grainstones (lokal Wackestones) aufgebaut und hat eine Mächtigkeit von etwa 30 m. Die hangende Einheit-C (etwa 34 m Mächtigkeit) ist durch Cyanobakterien-Krusten charakterisiert (stromatolithische Bindstones) und weist Stromatolithen bis 1 cm Höhe auf. Der Massenkalk des Schaufelsen kann daher in seinem überwiegenden Teil im untersuchten Profil weder als Schwammriff in weitester Bedeutung, noch als Schwamm-Stromatolith-Magnafazies bezeichnet werden.