Gingival hyperplasia is a common side-effect of immunosuppression with cyclosporine A. Nifedipine is often used to control hypertension in kidney graft recipients. Analysis of gingival status in 106 children transplanted at our centre, and treated either with azathioprine, cyclosporine A or both, revealed significantly higher degrees of gingival overgrowth in those children receiving a combination of cyclosporine A and nifedipine compared with those children treated with cyclosporine A or nifedipine alone. Seven children undergoing gingivectomy at our centre over the past few years had received this combination. After a change in the antihypertensive regimen, avoiding long-term nifedipine medication, and improved dental care with chlorhexidine gel, we noted a reduction in the degree of gingival hyperplasia. In the majority of patients, nifedipine could be replaced by a single drug, usually hydralazine. We therefore recommend avoiding calcium channel blockers in the long-term management of hypertension in patients receiving cyclosporine.

Background: Among different surgical approaches, dermabrasion and carbon dioxide laser vaporization have been used to treat Hailey-Hailey disease (HHD) (familial benign chronic pemphigus) and Darier disease (DD) (keratosis follicularis), with various results. Because of the erbium: YAG laser's unique absorption characteristics in tissue water, erbium:YAG laser ablation combines the advantages of both techniques, avoiding thermal injury of vaporization and also allowing selectively deeper tissue removal in the follicular lesions of DD. Therefore, good results should be expected in both types of acantholytic disorders.Observations: Four patients (2 with HHD and 2 with DD) with different affected areas were treated with laser ablation. During a follow-up period ranging from 8 to 20 months, complete remission was achieved in 3 patients-2 with DD and 1 with HHDand significant improvement was achieved in 1 patient with HHD. Histological examination of control biopsy specimens after ablation in 1 patient with DD revealed no signs of the disease and only a slight fibrosis in the papillary dermis.Conclusions: Erbium:YAG laser ablation effectively removes lesions of both HHD and DD and can also yield excellent long-term results in chronic, recalcitrant cases.

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Group B Streptococcus pili are covalently linked structures assembled via a sortase-catalyzed transpeptidation mechanism involving specific residues and motifs. A sequence element containing a conserved glutamic acid, called the E-box, has been described to be involved in pilus formation. Although it is known that the glutamic acid is involved in stabilizing the internal isopeptide bonds, its role in pilus assembly still needs to be investigated. Using site-specific mutagenesis and complementation studies of knockout strains, we found that the E-box glutamic residue of the backbone and the major ancillary proteins is essential for pilus protein polymerization. NMR analysis revealed that the mutation of this residue seriously affected the folding of the protein. By contrast, the mutation of the lysine involved in the same isopeptide bond did not engender a structural destabilization, and the native fold was preserved. Moreover, molecular dynamics simulations on the E-box-containing domain of the backbone protein showed that the E-box glutamic acid is necessary to maintain the appropriate dryness of the domain core and that its mutation favors an unfolded state. The data provide the first direct evidence that the E-box has an additional and key role in maintaining the correct protein fold independently of isopeptide bond formation.

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