Lytic to temperate switching of viral communities.

Microbial viruses can control host abundances via density-dependent lytic predator-prey dynamics. Less clear is how temperate viruses, which coexist and replicate with their host, influence microbial communities. Here we show that virus-like particles are relatively less abundant at high host densities. This suggests suppressed lysis where established models predict lytic dynamics are favoured. Meta-analysis of published viral and microbial densities showed that this trend was widespread in diverse ecosystems ranging from soil to freshwater to human lungs. Experimental manipulations showed viral densities more consistent with temperate than lytic life cycles at increasing microbial abundance. An analysis of 24 coral reef viromes showed a relative increase in the abundance of hallmark genes encoded by temperate viruses with increased microbial abundance. Based on these four lines of evidence, we propose the Piggyback-the-Winner model wherein temperate dynamics become increasingly important in ecosystems with high microbial densities; thus 'more microbes, fewer viruses'.

Spindle cell lipoma of the scalp: a case report and review.

Cutaneous surgeons frequently evaluate and manage soft tissue tumors arising on the head and neck of adults. Of these, the most common tumor is the lipoma, and specific mesenchymal variants of lipoma occur classically on the head and neck. We describe a case of a large spindle cell lipoma of the posterior scalp, in order to highlight the classic location and differential diagnosis of the lipoma variants presenting commonly in this anatomic region. In addition, we review the role of preoperative imaging studies of scalp soft tissue tumors and discuss how imaging may assist the dermatologic surgeon in establishing the diagnosis and designing a rational surgical approach.

Nodular fasciitis of the forehead.

BACKGROUND: Nodular fasciitis is a benign, fibrohistiocytic tumor most commonly arising on the trunk. Histopathologically it can be misdiagnosed as a sarcoma. OBJECTIVE: To describe a case of nodular fasciitis on the forehead and to review the clinical and histologic characteristics of the tumor. METHODS: Case report and review of the literature. RESULTS: Local excision to completely remove tumor has proven curative at 1 year of follow-up. CONCLUSION: Nodular fasciitis can be encountered on the head and neck and should be regarded as a benign tumor. Either minimal excision or even a "watch and wait" plan can be successful in treating this tumor.

Redox regulation of wound healing? NF-kappaB activation in cultured human keratinocytes upon wounding and the effect of low energy HeNe irradiation.

The complex process of wound healing as well as the signaling systems orchestrating this intricate process remain incompletely defined. Using human keratinocytes in primary culture, we sought to characterize their NF-kappaB responses to wounding alone or in combination with other treatments. We initially characterized these cultured human keratinocytes responses to known NF-kappaB activators (PMA, TNF-alpha and IL-1) using two different assays, immunohistochemistry and electrophoretic mobility shift (EMSA). After eliciting the expected NF-kappaB responses, we applied these same assays to assess responses to either wounding or HeNe irradiation alone. The results obtained indicated that only a modest/sporadic activation of NF-kappaB was elicited by these which was only detectable using immunohistochemistry. When the combination of wounding and HeNe irradiation on NF-kappaB status was assessed, a marked, localized activation of NF-kappaB in keratinocytes along the wound edge was found. Treatment induced NF-kappaB activation (e.g., wounding, HeNe irradiation and combined wounding and HeNe irradiation) was abrogated by pyrrolidine dithiocarbamate (PDTC) which inhibits NF-kappaB activation through an as yet incompletely understood (antioxidant?) mechanism. These data therefore suggest that NF-kappaB and oxidation mediated changes in its activation state likely play important roles in normal cutaneous wound healing.

Recalcitrant breast lymphangioma circumscriptum treated by UltraPulse carbon dioxide laser.

BACKGROUND: Lymphangioma circumscriptum is a relatively rare cutaneous disorder, consisting of superficial and deep lymphatic cisterns. These vascular blebs are difficult to treat, frequently recur, and can cause patients significant morbidity. OBJECTIVE: We report a difficult case of lymphangioma circumscriptum, recurrent from a two prior surgical treatments, which was treated in a straightforward manner by one of the newer, high-energy, short-pulse carbon dioxide (CO2) lasers. METHODS: Report of a case and literature review. CONCLUSION: Like continuous-wave CO2 laser systems, the newer, high-energy, short-pulse CO2 laser may be effective in vaporizing some of the surface lymphatic vessels, which may in turn seal some of the communicating channels to the deeper cisterns, yielding functionally and cosmetically acceptable results for this difficult disorder. However, given the nature of the lesion, the potential for recurrence exists no matter what modality is chosen.