Trachyonychia Secondary to Acitretin Usage.

Trachyonychia is a disease of the nail matrix that most commonly presents with sandpaper-like roughness of the nails. Retinoids are known to cause several nail abnormalities, likely due to their anti-proliferative effects. Despite this, no cases have been previously reported on the association of acitretin (second-generation retinoid) with trachyonychia. We present a single case of trachyonychia associated with acitretin that subsided following medication cessation.

Author Correction: Building a global alliance of biofoundries.

The original version of this Comment contained errors in the legend of Figure 2, in which the locations of the fifteenth and sixteenth GBA members were incorrectly given as '(15) Australian Genome Foundry, Macquarie University; (16) Australian Foundry for Advanced Biomanufacturing, University of Queensland.'. The correct version replaces this with '(15) Australian Foundry for Advanced Biomanufacturing (AusFAB), University of Queensland and (16) Australian Genome Foundry, Macquarie University'. This has been corrected in both the PDF and HTML versions of the Comment.

Modeling and comparing the organization of circular genomes.

MOTIVATION: Most prokaryotic genomes are circular with a single chromosome (called circular genomes), which consist of bacteria and archaea. Orthologous genes (abbreviated as orthologs) are genes directly evolved from an ancestor gene, and can be traced through different species in evolution. Shared orthologs between bacterial genomes have been used to measure their genome evolution. Here, organization of circular genomes is analyzed via distributions of shared orthologs between genomes. However, these distributions are often asymmetric and bimodal; to date, there is no joint distribution to model such data. This motivated us to develop a family of bivariate distributions with generalized von Mises marginals (BGVM) and its statistical inference. RESULTS: A new measure based on circular grade correlation and the fraction of shared orthologs is proposed for association between circular genomes, and a visualization tool developed to depict genome structure similarity. The proposed procedures are applied to eight pairs of prokaryotes separated from domain down to species, and 13 mycoplasma bacteria that are mammalian pathogens belonging to the same genus. We close with remarks on further applications to many features of genomic organization, e.g. shared transcription factor binding sites, between any pair of circular genomes. Thus, the proposed procedures may be applied to identifying conserved chromosome backbones, among others, for genome construction in synthetic biology. AVAILABILITY: All codes of the BGVM procedures and 1000+ prokaryotic genomes are available at http://www.stat.sinica.edu.tw/∼gshieh/bgvm.htm.

Web-based orthodontic instruction and assessment.

Orthodontic records-study models, panoramic and cephalometric radiographs, and the patient's facial and intraoral photographs-are used to collect data to establish a diagnosis and to develop problem-solution lists. These records, however, can be damaged or lost when dispensed to students and need to be stored and maintained every year. An orthodontic diagnosis web site, therefore, has been set up using digital records to provide students with an accessible source of complete, good-quality study materials. The web site is also used for clinical examination in orthodontic courses. The effectiveness of the web-based digital records in providing relevant information to students in comparison to the traditional records was evaluated by a randomized controlled trial involving ninety-nine second-year dental students. One group (fifty students) studied two cases from the web site; the other group (forty-nine students) studied the same two cases from traditional orthodontic records. Effectiveness was assessed by comparing test scores and the time spent on the tests by t-statistics. There were no significant differences between means for the two study groups in test performance or time. Attitudes of students toward the web site, assessed from post-test questionnaires, were positive. It was concluded that web-based digital orthodontic records were as effective in teaching clinical orthodontic diagnosis as were conventional records.

Granulomatous and suppurative dermatitis at interferon alfa injection sites: report of 2 cases.

It has previously been reported that interferon alfa injection sites may develop pyoderma gangrenosum, interface dermatitis, vasculitis, or, more commonly, ulcers characterized by intravascular thrombi and a mixed inflammatory cell infiltrate. We describe 2 patients in whom granulomatous and suppurative dermatitis developed at interferon alfa injection sites. These cases extend the spectrum of interferon alfa injection site reactions. The histologic and clinical similarities of these cases with pyoderma gangrenosum and cutaneous Crohn's disease are explored.