26856 Proliferative nodule resembling angiomatoid Spitz with pronounced degenerative atypia arising within a giant congenital nevus

Proliferative nodules arising within congenital melanocytic nevi present a diagnostic challenge for dematopathologists given their close resemblance to melanoma. In difficult cases, ancillary molecular tests can be used to better exclude the possibility of malignancy. We report case of a biopsy and subsequent excision of an unusual proliferative nodule with overlapping features of angiomatoid Spitz tumor and ancient melanocytic nevus which demonstrated normal findings on both chromosomal microarray and a gene expression profiling assay. Our case is noteworthy given its striking resemblance to what has been reported for an angiomatoid Spitz tumor. To our knowledge, this particular morphologic subset of Spitz has been described primarily in the context of spontaneous melanocytic tumors arising de novo outside the context of a congenital lesion. The pathology showed bizarre cytological features along with a myxoid and highly vascularized stroma which is thought to represent degenerative atypia characteristic of an “ancient nevus.” The lesions described as ancient nevi have some overlapping stromal features with angiomatoid Spitz tumors. A low proliferation index and paucity of mitotic figures is characteristic of these neoplasms. We hypothesize that continued host response to the lesion may be responsible for inducing the observed cytological and stromal derangement. Interestingly, these changes increased from the time of biopsy to the excision. Future studies should aim to define the genetic and immunologic signature of these lesions to help predict prognosis. The relationship between angiomatoid Spitz tumor, ancient change, and regressing nevi should also be investigated

Influence of edapho-climatic factors on the sporulation and colonization of arbuscular mycorrhizal fungi in two Amazonian native fruit species

Arbuscular mycorrhizal fungi (AMF) colonization and spore numbers in the rhizosphere of two fruit species, Paullinia cupana Mart. and Theobroma grandiflorum Schum., growing in a terra firme ecosystem in Central Amazonia were studied from August 1998 to May 2000. Climatic and edaphic factors were also determined to investigate their influence on mycorrhizal variables. Soil pH, Al, Mn and effective cation exchange capacity exhibited seasonal variations during the investigation period. Temporal variations in mycorrhizal colonization levels and spore numbers occurred, indicating seasonality. Moreover, the patterns of mycorrhizal colonization levels and spore numbers for both host species were similar during the studied period. Mycorrhizal variables were related to climatic and edaphic factors, however, the intensity and type of influence of climatic and soil characteristics on AMF development tended to vary with the season and host plant species in Central Amazonia conditions

Role of HxkC, a mitochondrial hexokinase-like protein, in fungal programmed cell death

Apoptosis is a form of programmed cell death (PCD) that occurs during animal development and is also triggered by a variety of signals including nutrient or oxidative stress, hypoxia, DNA damage, viral infection and oncogenic transformation. Though apoptotic-like PCD also occurs in plants and fungi, genes encoding several of the key players in mammalian apoptosis (p53 and BH-domain proteins) have not been identified in these kingdoms. In this report we investigated whether HxkC, a mitochondrial hexokinase-like protein, and XprG, a putative p53-like transcription factor similar to Ndt80, play a role in programmed cell death in the filamentous fungus 'Aspergillus nidulans'. We show that a mutant lacking HxkC is more sensitive to oxidative stress. Autolysis, a form of fungal programmed cell death triggered by carbon starvation, is accelerated in the hxkC∆1 mutant but not the hxkC∆1 xprG∆1 double mutant. In the absence of nutrient stress, the hxkC∆1 mutant displays XprG-dependent DNA fragmentation typical of apoptosis and elevated levels of intracellular protease. HxkC and XprG are required for catabolism of N-acetylglucosamine, as in 'Trichoderma reesei'. We show that XprG is present in the nucleus. We conclude that, like mammalian mitochondrial hexokinase, HxkC has anti-apoptotic activity and the XprG transcription factor has a pro-apoptotic role in filamentous fungi

A p53-like transcription factor similar to Ndt80 controls the response to nutrient stress in the filamentous fungus, 'Aspergillus nidulans'

The 'Aspergillus nidulans' xprG gene encodes a putative transcriptional activator that is a member of the Ndt80 family in the p53-like superfamily of proteins. Previous studies have shown that XprG controls the production of extracellular proteases in response to starvation. We undertook transcriptional profiling to investigate whether XprG has a wider role as a global regulator of the carbon nutrient stress response. Our microarray data showed that the expression of a large number of genes, including genes involved in secondary metabolism, development, high-affinity glucose uptake and autolysis, were altered in an xprGΔnull mutant. Many of these genes are known to be regulated in response to carbon starvation. We confirmed that sterigmatocystin and penicillin production is reduced in xprG⁻ mutants. The loss of fungal mass and secretion of pigments that accompanies fungal autolysis in response to nutrient depletion was accelerated in an xprG1 gain-of-function mutant and decreased or absent in an xprG⁻ mutant. The results support the hypothesis that XprG plays a major role in the response to carbon limitation and that nutrient sensing may represent one of the ancestral roles for the p53-like superfamily. Disruption of the AN6015 gene, which encodes a second Ndt80-like protein, showed that it is required for sexual reproduction in 'A. nidulans'

The impact of trace amounts of long wavelength UVA1 on visible light induced effects

Our skin is exposed to visible light (VL) and long wavelength ultraviolet A1 (UVA1) radiation (370-400 nm) present in sunlight even after application of organic broad spectrum sunscreens. The effects of these wavelengths on pigmentation and erythema have been demonstrated. However, a dose response has not been investigated which can provide insight on how skin responses can vary based on the duration of sun exposure. Ten subjects with Fitzpatrick skin phototype IV-VI were enrolled. On day 0, subjects were irradiated with two light source; one comprising pure VL and the other VL with less than 0.5% UVA1 (VL+UVA1) at a dose of 80 J/cm2, 160 J/cm2, 320 J/cm2 and 480 J/cm2. The irradiance was set at 175 mW/cm2. Skin responses were evaluated immediately, at 24 hours, 7 days, and 14 days after irradiation. Assessment methods included investigator’s global assessment (IGA), diffuse reflectance spectroscopy (DRS), and colorimetry. Clinical IGA scores suggest that 3/10 subjects for the 320 J/cm2 site, and 5/10 subjects for the 480 J/cm2 site had clinical erythema immediately after irradiation on the VL+UVA1 side only. No erythema was observed for the corresponding pure VL sites. Only the highest dose, 480 J/cm2,resulted in pigmentation response that was statistically significantly different at all time points between the two light sources (p\u3c0.05). Pigmentation response from VL+UVA1 site was two times more intense than that of pure VL at the day 14 time point. Spectroscopy and histology data analysis are under progress. Wavelengths not covered by current broad spectrum sunscreens have implications on pigmentation and erythema. There appears to be a threshold dose of UVA1 which in combination with VL results in immediate erythema followed by darker and persistent pigmentation. The effects can be noticed at approximately two hours of outdoor sun exposure

Efficacy evaluation of an antioxidant complex on visible light-induced biologic effects

Visible light and long wavelength ultraviolet A1 (VL+UVA1, 370-700 nm) have synergistic effects on pigmentation and erythema in darker skin individuals. This study evaluated VL+UVA1 skin responses in lighter skin individuals which have not been studied previously. Efficacy of an antioxidant complex on VL+UVA1 induced effects was also investigated for all skin phototypes (SPT). Twenty subjects, 10 SPT I-III and 10 SPT IV-VI were enrolled. Sites treated with three concentrations of a topical antioxidant complex (tocopherol, ascorbic acid, diethylhexyl syringylidene malonate, and caprylic/capric triglyeride) were compared to untreated control. The antioxidant complex was placed on participants’ back followed by VL+UVA1 irradiation with 480 and 320 J/cm2 for SPT 1-III and IV-VI respectively. Clinical and colorimetric assessments were performed immediately, at 24 hours, and 7 days after irradiation. All 10 SPT I-III subjects had erythema response immediately after irradiation at all sites. Colorimetry delta a* measurements demonstrated that the site treated with the highest concentration of the product had significantly lower erythema (p=0.007) compared to control. All 10 SPT IV-VI subjects had an immediate pigment darkening response. Colorimetry delta ITA measurements demonstrated that the site treated with the highest concentration of product was significantly lighter immediately after irradiation (p=0.005). At day 7, this trend continued although significance was not reached (p=0.07). The VL+UVA1 doses used in this study, 480 and 320 J/cm2, correspond to approximately 2.5 and 1.5 hours of sun exposure, respectively. The results provide evidence that these doses induce biologic effects in subjects with all skin phototypes. The antioxidant complex reduced the intensity of the VL+UVA1 induced effects, supporting the hypothesis that by quenching reactive oxygen species, antioxidant products may mitigate these effects

Conidial number data

<p>The number of asexual spores (conidia) per mm² produced by A. <em>nidulans</em> strains MH2 (<em>xpr</em>G⁺), MK422 (<em>xpr</em>GΔ) and MK85 (<em>xpr</em>G1) was determined by removing three plugs from colonies on complete medium containing 2.2% agar. The conidia from each plug were suspended in a solution of 0.01% TWEEN80 and counted in a haemocytometer. The experiment was repeated a total of four times using different batches of medium.</p