Root Coverage with Connective Tissue Graft in Patients with Thin Periodontal Biotype: A Case Series with 12-month Follow-up.

Preoperative gingival thickness is an important factor in the success of complete root coverage. Here, two cases are reported in which a biotype probe was used to assess the periodontal biotype before performance of a root coverage procedure. Clinical examinations were performed at baseline and at 3, 6, and 12 months postoperatively. The following clinical parameters were evaluated: probing depth, recession height, clinical attachment level, bleeding on probing, and width of keratinized gingiva. At baseline and at 12 months postoperatively, periodontal biotype was estimated using the biotype probe. The root coverage esthetic score was assessed to determine esthetic outcome at baseline and at 3, 6, and 12 months postoperatively. The periodontal biotypes in the mandibular central and lateral incisors were judged to be thin. These teeth presented with Miller Class II gingival recession after orthodontic therapy. Gingival recession was treated with a coronally advanced flap and autogenous connective tissue graft. In both cases, improvements in all clinical parameters and root coverage esthetic scores were evaluated at 3, 6, and 12 months postoperatively. The treated recession showed 100% root coverage. The periodontal biotype changed from one that was thin to one that was thick at the surgical sites. In both the present cases, objective preoperative assessment of the periodontal biotype allowed the appropriate surgical procedure to be selected.

Safety evaluation of dermal exposure to phthalates: Metabolism-dependent percutaneous absorption.

Phthalates, known as reproductive toxicants and endocrine disruptors, are widely used as plasticizers in polyvinyl chloride products. The present study was conducted for risk identification of dermal exposure to phthalates. When dibutyl phthalate was applied to the skin of hairless rats and humans, only monobutyl phthalate appeared through the skin, and the permeability of the skin was higher than that after the application of the monoester directly. The inhibition of skin esterases made the skin impermeable to the metabolite following dermal exposure to dibutyl ester, whereas removal of the stratum corneum from the skin did not change the skin permeation behavior. Similar phenomena were observed for benzyl butyl phthalate. The skin permeability of monobenzyl phthalate was higher than that of monobutyl phthalate in humans, although the reverse was observed in rats. Species difference in skin permeation profile corresponded to the esterase activity of the skin homogenate. Di(2-ethylhexyl) phthalate, which was not metabolized by esterases in the skin, was not transported across the skin. These results suggest that highly lipophilic phthalates may be transported easily across the stratum corneum lipids. The water-rich viable layer may become permeable to these phthalates by their metabolism into monoesters, which are relatively hydrophilic. Skin metabolism is essential to the percutaneous absorption of phthalates. Because esterase activity has large inter-individual differences, further study will be needed for individual risk identification of dermal exposure to phthalates.

Periodontal Surgery Involving Modified Widman Flap Procedure and Connective Tissue Graft for Generalized Aggressive Periodontitis: A Case Report.

We report a case of generalized aggressive periodontitis (AgP) requiring periodontal treatment including flap surgery and ridge augmentation. The patient was a 39-year-old woman who presented with the chief complaint of pus discharge from tooth #36. No other obvious signs of gingival inflammation were observed. Periodontal examination revealed multiple sites with a probing depth of ≥10 mm. Radiography showed pro-nounced bone defects in the maxillary incisors and molar region. Real-time PCR was used to detect Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Tannerella forsythia in subgingival plaque; all 3 pathogens were found. Based on a clinical diagnosis of generalized AgP, periodontal therapy was initiated, which resulted in an improvement in clinical and microbiological parameters. A modified Widman flap procedure was then performed on sites with residual periodontal pockets. Next, a connective tissue graft was performed for ridge augmentation at #22, which had shown evidence of ridge resorption. Postoperative reevaluation revealed a reduction in probing depth and an improvement in marginal bone levels. Oral function was then restored using a fixed bridge prosthesis and maintenance therapy initiated. The periodontal condition has remained stable over a 2.5-year period. In the present case of AgP, surgical intervention reduced periodontal pockets and periodontal pathogens and improved the architecture of both the hard and soft tissues, allowing subsequent care of the periodontium to be performed efficiently by the patient.

Exploring interactions between the 49 kDa and ND1 subunits in mitochondrial NADH-ubiquinone oxidoreductase (complex I) by photoaffinity labeling.

Quinazolines are strong inhibitors of NADH-ubiquinone oxidoreductase (complex I) from bovine heart mitochondria. Using a photoreactive quinazoline, [(125)I]AzQ, and bovine heart submitochondrial particles (SMPs), we demonstrated previously that [(125)I]AzQ binds at the interface of the 49 kDa and ND1 subunits in complex I; it labeled a site in the N-terminal (Asp41-Arg63) region of the 49 kDa subunit, suggesting that this region contacts the ND1 subunit [Murai, M., et al. (2009) Biochemistry 48, 688-698]. The labeled region of ND1 could not be identified because it is highly hydrophobic, and the SMPs did not yield sufficient amounts of labeled protein. Here, we describe how photoaffinity labeling of isolated complex I by [(125)I]AzQ yielded sufficient material for identification of the labeled region of the ND1 subunit. The inhibition of the isolated enzyme by AzQ is comparable to that of SMPs. Our results reveal that the labeled site in ND1 is between Asp199 and Lys262, mostly likely in the third matrix loop that connects the fifth and sixth transmembrane helices. Thus, our results reveal new information about the interface between the hydrophilic and hydrophobic domains of complex I, a region that is thought to be important for ubiquinone reduction and energy transduction.

Probing the role of tryptophan-derived secondary metabolism in defense responses against Bipolaris oryzae infection in rice leaves by a suicide substrate of tryptophan decarboxylase.

Tryptophan-derived secondary metabolites, including serotonin and its hydroxycinnamic acid amides, markedly accumulate in rice leaves in response to pathogen attack. These compounds have been implicated in the physical defense system against pathogen invasion by being deposited in cell walls. Serotonin is biosynthesized from tryptophan via tryptamine, and tryptophan decarboxylase (TDC) catalyzes the first committed reaction. In this study, (S)-α-(fluoromethyl)tryptophan (S-αFMT) was utilized to investigate the effects of the inhibition of TDC on the defense responses of rice leaves. S-αFMT, enantiospecifically synthesized from L-tryptophan, effectively inhibited TDC activity extracted from rice leaves infected by Bipolaris oryzae. The inhibition rate increased dependently on the incubation time, indicating that S-αFMT served as a suicide substrate. Treatment of rice seedlings with S-αFMT suppressed accumulation of serotonin, tryptamine, and hydroxycinnamic acid amides of serotonin in a dose-dependent manner in B. oryzae-inoculated leaves. The lesions formed on seedlings treated with S-αFMT lacked deposition of brown materials, and those leaves were severely damaged in comparison with leaves without S-αFMT treatment. Administrating tryptamine to S-αFMT-treated leaves restored accumulation of tryptophan-derived secondary metabolites as well as deposition of brown material. In addition, tryptamine administration reduced damage caused by fungal infection. Accordingly, the accumulation of tryptophan-derived secondary metabolites was suggested to be part of the effective defense mechanism of rice.

Characterization of the ubiquinone binding site in the alternative NADH-quinone oxidoreductase of Saccharomyces cerevisiae by photoaffinity labeling.

The Ndi1 enzyme found in the mitochondrial membrane of Saccharomyces cerevisiae is an NDH-2-type alternative NADH-quinone oxidoreductase. As Ndi1 is expected to be a possible remedy for complex I defects of mammalian mitochondria, a detailed biochemical characterization of the enzyme is needed. To identify the ubiquinone (UQ) binding site in Ndi1, we conducted photoaffinity labeling using a photoreactive biotinylated UQ mimic (compound 2) synthesized following a concept of the least possible modification of the substituents on the quinone ring. Cleavage with CNBr of Ndi1 cross-linked by 2 revealed the UQ ring of 2 to be specifically cross-linked to the Phe281-Met410 region (130 amino acids). Digestion of the CNBr fragment with V8 protease and lysylendopeptidase (Lys-C) gave approximately 8 and approximately 4 kDa peptides, respectively. The approximately 8 kDa V8 digest was identified as the Thr329-Glu399 region (71 amino acids) by an N-terminal sequence analysis. Although the approximately 4 kDa Lys-C digest could not be identified by N-terminal sequence analysis, the band was thought to cover the Gly374-Lys405 region (32 amino acids). Taken together, the binding site of the Q ring of 2 must be located in a common region of the V8 protease, and Lys-C digests Gly374-Glu399 (26 amino acids). Superimposition of the Ndi1 sequence onto a three-dimensional structural model of NDH-2 from Escherichia coli suggested that the C-terminal portion of this region is close to the isoalloxazine ring of FAD.