Aesthetic management of extractions for implant site development: delayed versus staged implant placement.

Resorption of the dentoalveolar bone and collapse of the gingival ridge following tooth loss often results in aesthetic compromise and inadequate bone for "prosthetically driven" implant placement. Preventing alveolar bone resorption with a conservative procedure at the time of extraction can enhance aesthetics and reduce the duration and extent of treatment required for implant placement. This article describes the aesthetic management of extraction sites using a conservative bone grafting procedure at the time of extraction for implant site development. The case presented demonstrates staged and delayed implant placement techniques.

Thioltransferase from Arabidopsis thaliana seed: purification to homogeneity and characterization.

Thioltransferase is a general GSH-disulfide reductase of importance for redox regulation. The protein thioltransferase has been purified to apparent homogeneity on SDS-PAGE from the Arabidopsis thaliana seed. The purification procedures included DEAE-cellulose ion exchange chromatography, Sephadex G-75 gel filtration, Q-Sepharose ion exchange chromatography, and DEAE-Sephadex A-25 ion exchange chromatography. The enzyme has a molecular mass of 22 kDa and a pI of 4.8, and it is heatstable. The protein had broad specificities for substrates ranging from low-molecular disulfides (S-sulfocysteine and cystine) to protein disulfides (trypsin and insulin). However, it could not reduce the disulfide linkages of ribonuclease A and bovine serum albumin. It could utilize non-disulfide substrates such as dehydroascorbic acid and alloxan. The protein can reduce the disulfide bond in 2-hydroxyethyl disulfide with an optimum pH of 8.5. Its activity was greatly activated by monothiol compounds such as reduced glutathione and L-cysteine.

Cloning of a cDNA encoding phospholipase D from Pimpinella brachycarpa.

Phospholipase D (PLD, EC 3.1.4.4) has been known to be related to various cellular processes in plants. To gain an understanding of the property of the enzyme in Pimpinella brachycarpa, the cDNA of the enzyme was isolated by PCR with degenerate primers, cDNA library screening, and 5' RACE. The full-length PLD cDNA is 2859 bp long and contains an open reading frame of 2424 bp coding for a polypeptide of 808 amino acids. The deduced enzyme has a calculated molecular mass of 91.7 kDa and pI of 5.86. The percent identity and similarity values of P. brachycarpa PLD with those of other PLDs in plants are 70 approximately 78 and 84 approximately 95, respectively. It was identified that PLD from P. brachycarpa has HQKIVVVD and HAKMMIVD sequences which were homologous with a duplicated HXKXXXXD motif that has been conserved in PLDs from plants, animals, and yeast. Based on the analysis of amino acid similarity, it is believed that PLD from P. brachycarpa is an alpha form which is distinct from PLD beta reported recently. The N-terminus is homologous to the C2 domain which is present in a number of different proteins involved in signal transduction and membrane trafficking in animals. Southern and northern blot analyses indicated that PLD was expressed from one copy of PLD gene in the genome of P. brachycarpa.

Regulated expression of a calmodulin isoform alters growth and development in potato.

A transgene approach was taken to study the consequences of altered expression of a calmodulin isoform on plant growth and development. Eight genomic clones of potato calmodulin (PCM1 to 8) have been isolated and characterized (Takezawa et al., 1995). Among the potato calmodulin isoforms studied, PCM1 differs from the other isoforms because of its unique amino acid substitutions. Transgenic potato plants were produced carrying sense construct of PCM1 fused to the CaMV 35S promoter. Transgenic plants showing a moderate increase in PCM1 mRNA exhibited strong apical dominance, produced elongated tubers, and were taller than the controls. Interestingly, the plants expressing the highest level of PCM1 mRNA did not form underground tubers. Instead, these transgenic plants produced aerial tubers when allowed to grow for longer periods. The expression of different calmodulin isoforms (PCM1, 5, 6, and 8) was studied in transgenic plants. Among the four potato calmodulin isoforms, only the expression of PCM1 mRNA was altered in transgenic plants, while the expression of other isoforms was not significantly altered. Western analysis revealed increased PCM1 protein in transgenic plants, indicating that the expression of both mRNA and protein are altered in transgenic plants. These results suggest that increasing the expression of PCM1 alters growth and development in potato plants.

Strip gingival autograft used to correct mucogingival problems around implants.

This case report describes the use of a strip gingival autograft to transplant narrow strips of keratinized gingiva around dental implants. Replacement of unattached, nonkeratinized mucosa with keratinized gingiva resulted in firmly attached gingiva and an improved seal around implants that was healthier and more resistant to inflammation. The strip gingival autograft technique is a simple surgery that results in less discomfort for the patient and provides predictable results.

The strip gingival autograft technique.

In keeping with the concept of rapid epithelialization of close wound edges, the strip technique was developed to maximize the area of gingival grafting with less trauma to the donor site or the recipient site. An incision is made and a partial-thickness flap is reflected so that stable periosteum is left. The apical mucosal border of the recipient site is sutured to the periosteum. Donor tissues are obtained in 2-mm-wide strips, transferred to the recipient site, and sutured. Dry foil and surgical packing are used to stabilize and protect the site during healing. The donor site is rapidly epithelialized (within 10 days) and produces minimal patient discomfort.

Electrophoretic and chemical characterization of lipopolysaccharides of Vibrio parahaemolyticus.

Lipopolysaccharides (LPSs) isolated from three Kanagawa-positive and three negative strains of Vibrio parahaemolyticus were characterized by using electrophoretic, immunochemical, and chemical methods. The results of this study indicated that the LPSs of all six strains of V. parahaemolyticus examined did not have an O-specific side chain. These V. parahaemolyticus LPSs appeared to have molecular weights similar to that of the rough-type (Ra) LPS of Salmonella typhimurium TV-119 and might just contain lipid A and a core region. However, the microheterogeneity of V. parahaemolyticus LPS observed was greater than that of S. typhimurium LPS. The profile of V. parahaemolyticus LPS consisted of closely spaced triplet or quadruplet bands, but that of S. typhimurium consisted of doublet bands. Slower-moving bands appeared on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels only when large amounts of V. parahaemolyticus LPS were loaded. These bands were proven to be the aggregates of the fastest-moving low-molecular-weight bands by re-electrophoresis. The banding pattern of V. parahaemolyticus LPSs produced on nitrocellulose membranes by immunoblotting indicated that the V. parahaemolyticus LPSs did not have an O-specific side chain. The low ratio of total carbohydrate to lipid A of V. parahaemolyticus LPSs also suggested that they were like rough-type LPS. The mobility and profile of V. parahaemolyticus LPS on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gel and its chemical composition were closely related to the serotype of a specific strain but not with the Kanagawa phenomenon.

Occurrence of 2-keto-3-deoxy-D-manno-octonic acid in lipopolysaccharides isolated from Vibrio parahaemolyticus.

The occurrence of 2-keto-3-deoxy-D-manno-octonic acid (KDO) in lipopolysaccharides (LPS) of Vibrio parahaemolyticus was demonstrated for the first time by gas chromatography-mass spectrometry after dephosphorylation, reduction, and methylation. KDO was virtually completely phosphorylated, since no KDO was detected by either gas chromatography or thiobarbituric acid assay before dephosphorylation. The level of KDO in all six strains of V. parahaemolyticus investigated ranged from 0.37 to 0.69%, which was considerably lower than that in enterobacterial LPS.

Alloplastic materials in reconstructive periodontal surgery.

Alloplastic implants, especially those made with calcium phosphate ceramics, are being increasingly used in reconstructive periodontal surgery. Despite attractive generic features such as good biocompatibility, these ceramic implants differ significantly from each other in terms of biologic profile. Variations in source material used, manufacturing process, and physical and chemical properties determine the clinical utility of these implants. Porous hydroxyapatites currently are favored, especially those with natural morphologic characteristics. These ceramic implants appear to serve as biocompatible fillers that accelerate bone healing when used for the right clinical indications. It is anticipated that alloplastic implants eventually will form a part of the periodontist's armamentarium.

Lipid peroxidation enzyme system in rainbow trout (Salmo gairdnerii) skeletal muscle microsomes.

1. A microsomal lipid peroxidation enzyme system in rainbow trout white skeletal muscle was identified and characterized. 2. This enzyme system is very similar to that found in other fish such as red hake, winter flounder and herring. 3. NADH-cytochrome b5 reductase is suggested to be the enzyme involved, because of the specific requirement for NADH as the electron donor, the inhibition of enzyme activity by p-hydroxy-mercuribenzoate and the involvement of chelated non-heme iron. 4. The activating and inhibitory effects of EDTA and KCN on lipid peroxidation enzyme system activity at different concentrations are discussed extensively in terms of the possible initiation reaction mechanism.

Flap technique for periodontal bone implants. Papilla preservation technique.

A new flap design for placement of implants into osseous defects has been described. The flap design can be used in anterior and posterior areas of human subjects. Photographs of representative cases are presented. Wound healing always occurred by primary intention and without evidence of immediate graft exfoliation. Interdental soft tissue craters did not develop, making it easier for patients to maintain optimal oral hygiene. This type of flap design can also be used without grafts in order to improve postoperative soft tissue contour.