Instant loading with intraoral welding technique and PRAMA implants: a new prosthetic approach

When splinting multiple implants passive fit of the framework should be achieved to avoid excessive force distribution on the implants. Recently, a protocol was suggested for immediate loading of multiple implants by welding a titanium bar to implant abutments directly in the oral cavity so as to create a customized, precise and passive metal-reinforced provisional restoration. The intraoral welding technique subsequently proves to be a successful option in the full-arch immediate restorations of the mandible and maxilla. The aim of this article is to present a case report in which a new prosthetic approach, using trans-mucosal implants, is described. Dental implants are instantly loaded with a provisional prosthesis supported by an intraoral welded titanium framework to obtain a precise passive fit of the immediate loaded prosthesis.

Biomechanical considerations on macromorphology of endosseous dental implants

The aim of the present study is to define the optimal thread form and why the macroscopic shape of the dental intra-osseous implant interacts with the biological environment thus conditioning its lifespan and long-term success.

Static and fatigue resistance of two types of implant/abutment connectors

The aim of this study is to determine in an experimental way through mechanical tests the static, fatigue and torque resistance of two types of implant/abutment connectors with diameters of 3.4–5.2 mm.

Wide Diameter Implants: Analysis of a Case Series

In the last decade the use of wide diameter implants (WDI, i.e. diameter > 3.75 mm) has increased especially in posterior jaws because it is generally accepted that WDI: 1- improve the ability of posterior implants to tolerate occlusal forces, 2- create a wider base for proper prosthesis, and 3- avoid placing two standard-size implants (SSI = 3.75 mm) at one site to obtain a double-root prosthetic tooth. Since no report is available on a new type of implants, a retrospective study was performed. A total of 124 two-piece implants (FMD srl, Rome, Italy) were inserted, 56 in female and 68 in males. The median age was 59 ± 12 (min-max 28–75 years). Implants were inserted 59 in the maxilla and 65 in the mandible; they replaced 7 incisors, 4 cuspids, 23 premolars and 90 molars. One implant was lost, survival rate = 99.20%. Among the studies variables immediate loaded implants (p=0.05) and upper jaw (p=0.005) have a statistically significant worse outcome. Then peri-implant bone resorption (i.e. delta IAJ) was used to investigate SCR. Among the remaining 123 implants, 2 fixtures have a crestal bone resorption greater than 1.5 mm (SCR = 97.54). Statistical analysis demonstrated that single crown have a higher peri-implant crestal bone resorption if compared with bridge supported by 2 or more implants (p=0.03). In conclusion FMD implants are reliable devices for oral rehabilitation with a very high SCR and SVR.

Effect of Narrow Diameter Implants on Clinical Outcome

Narrow diameter implants (NDI) (i.e. diameter 3.75 mm) are a potential solution for specific clinical situations such as reduced interradicuiar bone, thin alveolar crest and replacement of teeth with small cervical diameter. NDI have been available in clinical practice since the nineties but only a few studies have analyzed their clinical outcome. Since no report is available on a new type of implants, a retrospective study was performed. A total of 47 narrow diameter (i.e. x ≤ 3.40 mm) two-piece implants (FMD srl, Rome, Italy) were inserted, 35 in females and 12 in males. The median age was 60 ± 11 (min-max 30–80 years). Implants were inserted 22 in the maxilla and 25 in the mandible; they replaced 11 incisors, 3 cuspids, 21 premolars and 12 molars. Implant' length was shorter than 10 mm, 10.30 ≤ x ≤ 12.30, equal to 13 mm and longer than 13 mm in 17,28,1 and 1 fixtures, respectively. Implant' diameter was narrower than 3.5 mm. There were 3,18 and 26 Elisir, I-fix and Shiner implant types. No implant on single tooth rehabilitations was lost and thus survival rate was 100%. Then peri-implant bone resorption (i.e. delta IAJ) was used to investigate SCR. Seven fixtures have a crestal bone resorption greater than 1.5 mm (SCR = 85.1). Statistical analysis demonstrated that diabetes (p=0.044) and smoke (p=0.001) have a higher peri-implant crestal bone resorption. In conclusion FMD implants are reliable devices for oral rehabilitation with a very high SCR and SVR although smoker and diabetic patients have a worse clinical outcome.

Titanium Disk Surfaces Modulate Dental Implants Osseointegration

Titanium and titanium alloys are widely used as implant materials due to their excellent biocompatibility and mechanical properties. The aim of this work is to compare five different titanium layers in order to investigate which one had a greater osteoconductive power using Human Osteoblasts (HObs) culture for seven days on these surfaces. The expression levels of some bone-related genes (ALPL, COL1A1, COL3A1, SPP1, RUNX2 and SPARC) were analyzed using real time Reverse Transcription-Polymerase Chain Reaction (real time RT-PCR). Results obtained in this study demonstrate that titanium disks can lead to osteoblast differentiation and extracellular matrix deposition and mineralization by the activation of different osteoblast genes in relation to the specific type of surface treatment.

Implants Inserted in Mandible: A Case Series

It is generally accepted that the mandible (especially in the interforaminal region) has better bone quality than the maxilla, and this fact is probably the reason why several reports are available regarding implants inserted into the mandible. Since no report is available on a new type of implants, a retrospective study was performed. A total of 185 two-piece implants (FMD srl, Rome, Italy) were inserted in mandible, 102 in female and 83 in males. The median age was 58 ± 13 (min-max 25–80 years). Implants replaced 14 incisors, 7 cuspids, 49 premolars and 115 molars. Implant' length was x ≤ 10 mm, 10,30 ≤ x ≤ 12.30, equal to 13 mm and x ≥14 mm in 80, 90,13 and 2 cases, respectively. Implant' diameter was narrower than 3.5 mm, equal to 3.8 mm and wider than 4.0 mm in 25, 17,143 cases, respectively. There were 36,41,106 and 2 Elisir, I-fix, Shiner, and Storm implant types, respectively. One implant was lost, survival rate = 98.15%. Among the studies variables immediate loaded implants on single tooth rehabilitations (p=0.017) have a worse clinical outcome. Then peri-implant bone resorption (i.e. delta IAJ) was used to investigate SCR. Among the remaining 184 implants, 20 fixtures have a crestal bone resorption greater than 1.5 mm (SCR = 89.13). Statistical analysis demonstrated signifiance only for surgeon (p=0.001). In conclusion FMD implants are reliable devices for oral rehabilitation with a very high SCR and SVR.

Reliability of Short Implants in Oral Rehabilitation

Implant prostheses are often used to restore partially or completely edentulous patients but limited bone height, especially in the posterior mandible, may restrict the use of dental implants. Short implants (i.e. x ≤ 10 mm) may be selected in these situations. They have several advantages: 1 - restricting the need for sophisticated and expensive surgical procedures like sinus lifting, bone grafting and mandibular nerve transposition, 2 - placing short-span dentures and 3 - avoiding cantilevers in the posterior sextants. The limited surface area of SIs, conversely, can be a potential disadvantage as it has less resistance to occlusal forces. Since no report is available on a new type of implants, a retrospective study was performed. A total of 148 short (i.e x ≤ 10 mm) two-piece implants (FMD srl, Rome, Italy) were inserted, 91 in female and 57 in males. The median age was 58 ± 12 (min-max 25–80 years). Implants were inserted 68 in the maxilla and 80 in the mandible. One implant was lost, survival rate = 98.52%. Among the studies variables post-extractive implants on single tooth rehabilitations (p=0.043) was the only significant variable. Then peri-implant bone resorption (i.e. delta IAJ) was used to investigate SCR. Among the remaining 147 implants, 18 fixtures have a crestal bone resorption greater than 1.5 mm (SCR = 87.75). Statistical analysis demonstrated that only diabetes has a negative impact on peri-implant crestal bone resorption (p=0.016). In conclusion FMD implants are reliable devices for oral rehabilitation with a very high SCR and SVR.

Implants Inserted in Different Sites: Analysis of 390 Fixtures

Oral rehabilitation by means dental implants is a surgical procedure with high standards of success. Since very few reports focus on clinical success related to implant site and no report is available on a new type of implants (FMD srl, Rome, Italy), a retrospective study was performed. A total of 390 two-piece implants were inserted, 213 in females and 177 in males. The median age was 59 ± 11 (min-max 24–80 years). Two hundred and five implants were inserted in upper jaw and 185 in mandible. Three implants were lost, survival rate = 99.23%. Among the studies variables immediate loaded implants on single tooth rehabilitations (p=0.047) have a worse clinical outcome. Then peri-implant bone resorption (i.e. delta IAJ) was used to investigate SCR. Among the remaining 387 implants, 47 fixtures have a crestal bone resorption greater than 1.5 mm (SCR = 87.85). Statistical analysis demonstrated that no studied variable has an impact on clinical outcome and thus there are no differences in term of SVR and SCR by sites. In conclusion FMD implants are reliable devices for oral rehabilitation with a very high SCR and SVR.

Retrospective Study on 205 Fixtures Inserted in Upper Jaw

The rehabilitation of the edentulous maxilla is a relatively common clinical problem and to submerge dental implants during the healing period is a major prerequisite to obtain implant osseointegration. It is believed that micromovement of implants, due to functional forces at the bone-implant interface during wound healing, could induce the formation of fibrous tissue rather than bone, leading to a clinical failure. In addition, the coverage of an implant is also thought necessary to prevent infection and epithelial down-growth. Usually, the second surgical procedure was performed after three months in the mandible and six months in the maxilla. Since no report is available on a new type of implants, a retrospective study was performed on fixtures inserted in upper jaw. A total of 205 two-piece implants (FMD srl, Rome, Italy) were inserted in maxilla, 111 in female and 94 in males. The median age was 59 ± 10 (min-max 24–80 years). Twenty four diabetic patients were enrolled, 141 had periodontal disease and 96 were smokers. Two surgeons performed operation. Fixtures were placed in 6 totally edentulous patient, 9 single missing teeth and 190 partially edentulous subjects. Twenty one implants were placed in post-extraction sockets; GBR was performed onto 26 fixtures and 3 were immediately loaded. There were 109 single crowns, 96 implants bearing 2 or greater bridges. Two implants were lost, survival rate = 99.02%. Among the studies variables immediate loaded implants on single tooth rehabilitations (p=0.03) have a worse clinical outcome. Then peri-implant bone resorption (i.e. delta IA J) was used to investigate SCR. Among the remaining 203 implants, 20 fixtures have a crestal bone resorption greater than 1.5 mm (SCR = 89.13). Statistical analysis demonstrated that diabetes (p=0.001) and periodontal disease (p=0.047) had a worse outcome. In conclusion FMD implants are reliable devices for oral rehabilitation with a very high SCR and SVR.

Gene Expression Study in Dental Pulp Stem Cells Cultivated on Titanium Alloys

Nowadays, research on orthopedic and dental implants is focused on titanium alloys due to their appropriated mechanical properties and corrosion resistance in the body environment. Another important aspect to be investigated is their surface topography, which is very important to osseointegration. The aim of this study was to assess dental pulp stem cells response to different titanium surface topography modified. Mesenchymal stem cell marker ENG was significantly decreased in stem cells cultivated in modified titanium surface respect to machined titanium surface, indicating the differentiation effect of this biomaterial on stem cells. The obtained results can be relevant to better understand the molecular mechanism of bone regeneration and as a model for comparing other materials with similar clinical effects.

Titanium Disk Surfaces Modulate Fibroblasts Behavior

Titanium (Ti) is the most widely used material in implantology for dental, orthopedic and maxillofacial purposes due to their excellent biocompatibility and mechanical properties Several data suggest that implant anchorage to bone and soft tissue can be modulated by surface characteristics. Fibroblasts are the soft tissues cells concerned in producing extracellular matrix and collagen. The aim of this work is to compare five different titanium surface treatments in order to investigate which one had the best behavior using Human Fibroblast (HFb) after seven days in culture medium. The expression levels of some adhesion and traction-resistance related genes (COL11A1, COL2A1, COL9A1, DSP, ELN, HAS1, and TFRC) were analyzed using real time Reverse Transcription-Polymerase Chain Reaction (real time RT-PCR). Titanium disks can lead to implant integration promoting the production of protein involved in cell-cell and cell-matrix adhesion and in stress-resistance, required for a good outcome in dental implantology

The importance of immediately loaded immediate post-extractive implants in esthetical rehabilitation: case series

The aim of this paper was to estimate, in a retrospective way, integration of hard and soft tissues in immediately loaded immediate postextractive implants. Benefits of this technique could be: single stage surgery, biological saving of tissues, aesthetic management of edentulism, good integration of both hard and soft tissues. Immediate loading of a postextractive implant seems also to produce a positive effect on the quality of perimplant soft tissues. The implants used in the present study have some advantages such as high auto-threading and auto-tapping ability, progressive increase of the thickness of the threads, at the apical and coronal level. All these features have helped to obtain a high primary stability.

Capillary electrophoretic analysis of the antibiotic vancomycin in innovative microparticles and in commercial formulations

A new fast capillary electrophoretic method has been developed for the analysis of the glycopeptide antibiotic vancomycin in formulations. An electrophoretic run is completed within 3.0 min; fused silica capillaries (100 microm i.d., 8.5 cm effective length and 48.5 cm total length) and a background electrolyte consisting of 12.5 mM, pH 2.5 phosphate buffer are used. The applied voltage is -20.0 kV; samples are injected by pressure (30 mbar x 3 s) at the anodic end of the capillary. The method was successfully applied to innovative controlled release microparticles consisting of a coated albumin core containing vancomycin. A simple procedure has been developed to obtain complete vancomycin extraction from microparticles using a 5% (w/v) sodium dodecyl sulphate aqueous solution. The method has been validated in terms of linearity, precision and accuracy. Good linearity was found in the 0.25-5.00 microg/mL range. Satisfactory precision was obtained, with relative standard deviation values always lower than 3.9%; accuracy was satisfactory, with recovery values between 97.8 and 102.2%. The method is also suitable for vancomycin determination in commercial capsules.

Use of vancomycin chiral stationary phase for the enantiomeric resolution of basic and acidic compounds by nano-liquid chromatography

In this paper we studied the potentiality of nano-liquid chromatography (nano-LC) for the enantiomeric resolution of both basic and acidic compounds of pharmaceutical interest using a vancomycin modified silica stationary phase. Experiments were carried out in a fused silica capillary of 75 microm I.D. packed with chiral modified silica particles of 5 microm diameter, the detection, was done on-line at 195 nm. Enantiomeric resolution of alprenolol, atenolol, metoprolol, oxprenolol, pindolol, propranolol (basic compounds) and some acidic analytes, namely 2-[(5'-benzoyl-2'-hydroxy)phenyl]propionic acid (DF1738Y), 2-[(4'-benzoyloxy-2'-hydroxy)phenyl]propionic acid (DF1770Y), ketoprofen, indoprofen and suprofen was studied by nano-LC utilizing mobile phases containing methanol-acetonitrile-ammonium formate or acetate. The effect of mobile phase composition (buffer type and concentration, organic modifier type and concentration) on chiral resolution (Rs), retention factor (k) and retention time (tR) was also investigated. Good enantiomeric resolution was achieved for basic compounds utilizing the mobile phase containing 90% (MeCN-MeOH)/5% water/5% of 100 mM ammonium acetate pH 4.5. Acidic compounds such as DF1738Y and DF1770Y were better resolved at lower pH 3.5 while ketoprofen, indoprofen and suprofen exhibited the highest resolution at pH 4.5; in this case the mobile phase contained MeOH or MeCN (90%), 5% buffer and 5% of water. The nano-LC method was validated using R-(+)-propranolol as an internal standard finding good repeatability, detection limit, correlation coefficient and recovery and applied to the assay of a pharmaceutical formulation containing a racemic mixture of metoprolol.

Analysis of diltiazem and its related substances by HPLC and HPLC/MS

Diltiazem (DTZ) is an optically active calcium channel blocker having a benzodiazepine structure. The drug used in therapy is (+)-cis-diltiazem with configuration (2S,3S). To describe the analytical profile of DTZ different stationary phases (RP-18, RP-8, monolithic support) were tested. The best separation of DTZ from A, B, E and F was obtained using as stationary phase a RP-8 or a monolithic RP-18. The characterization of impurities was carried out using two analytical systems, HPLC and HPLC/MS.

Direct determination by capillary electrophoresis of cardiovascular drugs, previously included in liposomes

The lipophilicity of some cardiovascular drugs was determined by capillary electrophoresis (CE). Mexiletine, amlodipine and indapamide, the drugs considered, were in contact with liposomial vescicles for 2, 4 or 6 h. After the contact time the drugs, penetrated into liposomial vesicles, were determined by CE using phosphate buffer (pH 6.3 or 7.4) or borate buffer (pH 9). The lipophilicity of three drugs was determined considering the drug percentage penetrated into liposomial vesicles. The found lipohilicity order was amlodipine > mexiletine > indapamide.

Micellar electrokinetic chromatography for determination of drug partition in phospholipids

The lipophilicity of pipemidic, nalidixic and oxolinic acids was determined by forming phospholipidic micelles directly in an electrophoretic capillary. Phosphatidylcholine derivatives, namely L-alpha-dilauroyl phosphatidylcholine (DLPC) or L-alpha-dimiristoyl phosphatidylcholine (DMPC), were added in the run buffer (50 mM phosphate buffer at pH 7.4). To obtain a mixed micelle, phospholipidic derivatives and sodium cholate were together added in the run buffer. Considering the increasing of migration time when phosphatidylcholine derivative is added in the run buffer, Ks can be determined and then quinolones lipophilicity.

Micellar electrokinetic chromatography for the simultaneous determination of ketorolac tromethamine and its impurities

A simple, fast and selective micellar electrokinetic chromatographic (MEKC) method for the simultaneous assay of ketorolac tromethamine and its known related impurities (1-hydroxy analog of ketorolac, 1-keto analog of ketorolac and decarboxylated ketorolac), in both drug substance and coated tablets, is described. The compounds were detected at 323 nm, and flufenamic acid (FL) and tolmetin (TL) were chosen as internal standards to quantify ketorolac tromethamine and impurities, respectively. The multivariate optimization of the experimental conditions was carried out by means of the response surface study, considering as responses the resolution values and analysis time. The optimized background electrolyte (BGE) consisted of a mixture of 13 mM boric acid and phosphoric acid, adjusted to pH 9.1 with 1 M sodium hydroxide, containing 73 mM sodium dodecyl sulfate (SDS). Optimal temperature and voltage were 30 degrees C and 27 kV. Applying these conditions, all compounds were resolved in about 6 min. The related substances could be quantified up to the 0.1% (w/w) level. Validation was performed, either for drug substances and drug product, evaluating selectivity, robustness, linearity and range, precision, accuracy, detection and quantitation limits and system suitability.

Ibuprofen quality control by electrochromatography

The quality control of drugs is generally made by HPLC. This control could be made also by capillary electrochromatography (CEC). In this paper we report the analysis by CEC of ibuprofen, a well-known anti-inflammatory non steroidic drug, and some of its impurities. The analyses were performed in a 100-microm inner diameter (I.D.) fused silica capillary, packed with RP-18 stationary phase. The mobile phase was a mixture of 100 mM formic acid solution (pH 2.5), water and acetonitrile (ACN). The ACN percentage in the mobile phase and the applied voltage were carefully studied to well resolve the drug from each impurity. The results, obtained determining ibuprofen and related compounds by CEC, showed the selectivity and efficiency of the method.

HPLC analysis of the novel antipsychotic drug quetiapine in human plasma

A precise and feasible high-performance liquid chromatographic (HPLC) method for the analysis of the novel antipsychotic drug quetiapine in plasma has been developed. The analysis was carried out on a C8 (150x4.6 mm i.d., 5 micrometer) reversed-phase column, using a mixture of acetonitrile, methanol and pH 1.9 phosphate buffer as the mobile phase; triprolidine was used as the internal standard. Careful pretreatment of the biological samples was implemented by means of solid-phase extraction (SPE). A good linearity was found in the 4-400 ng ml(-1) quetiapine plasma concentration range. The application to some plasma samples of patients treated with Seroquel(R) tablets gave satisfactory results. The accuracy was good (quetiapine mean recovery=92%), as well as the precision (mean RSD=3.3%). The method seems to be suitable for the clinical monitoring of patients treated with quetiapine.

Determination of losartan and hydrochlorothiazide in tablets by CE and CEC

Capillary Electrophoresis (CE) and Capillary Electrochromatography (CEC) have been used to determine losartan and hydrochlorothiazide. The CE separation was carried out in an uncoated capillary filled with a 100 mM sodium borate pH 9 solution containing trimethyl-beta-cyclodextrins. CEC was performed using a capillary packed with a RP-18 stationary phase. The mobile phase was a mixture of 50 mM ammonium acetate pH 7, water, acetonitrile (1/1.5/7.5). By CE and CEC suitable methods to determine simultaneously losartan and hydrochlorothiazide in working standard mixture or pharmaceutical form were obtained. The proposed methods are very simple and both gave accurate and precise results.

An experimental design methodology applied to the enantioseparation of a non-steroidal anti-inflammatory drug candidate

An experimental design methodology has been applied to the enantioseparation of a new synthesized aryl propionic acid of pharmaceutical interest, namely 2-[(4'-benzoyloxy-2'-hydroxy)phenyl-propionic acid] (DF-1770y) by chiral capillary zone electrophoresis (CCZE). The chiral separation of the studied compound has been achieved employing vancomycin as the chiral selector. The partial filling-counter current method has been used in order to avoid the presence of the absorbing chiral selector in the path length of the detector and to increase the method sensitivity. A central composite design has been employed to optimize the experimental conditions for a fast separation of the enantiomers of the new synthesized aryl propionic acid. Critical parameters such as chiral selector concentration, pH and temperature have been studied to evaluate how they affected responses such as resolution and migration times. The desirability function approach has been employed in order to find the best compromise between the different experimental responses. The proposed CCZE method provided the baseline enantioseparation of the investigated drug. A Britton-Robinson buffer at pH 6.4 supplemented with 7 mM of vancomycin at 22 degrees C and -20 kV were the optimum experimental conditions allowing to achieve the highest enantioresolution of DF-1770y in less than 8.5 min.

Chiral discrimination by HPLC and CE and antifungal activity of racemic fenticonazole and its enantiomers

Fenticonazole is a chiral antifungal agent, used in therapy as the racemic mixture. The investigation on the chirality of fenticonazole is reported in this study. rac-Fenticonazole was resolved by HPLC and by capillary electrophoresis (CE). The chiral stationary phase (CSP), used in HPLC, was Daicel OD-H, a commercial phase, which allowed the separate collection of the two enantiomers. The chiral selectors used for CE were some cyclodextrin derivatives. The analysis time required from CE was about the half the HPLC enantioseparation time. The biological activity of the rac-mixture and each individual enantiomer was tested against Cryptococcus neoformans and two Aspergillus nidulans strains. The minimum inhibitory concentration (MIC) evaluation showed that the eutomer was the enantiomer chromatographically more retained and had a longer migration time in the electrophoretic enantioseparation. The CD spectrum of the eutomer showed a positive Cotton effect.

Analysis of reboxetine, a novel antidepressant drug, in pharmaceutical tablets by capillary electrophoresis and derivative spectrophotometry

The recent antidepressant drug reboxetine was quantified in pharmaceutical tablets by derivative spectrophotometry and capillary zone electrophoresis. The feasible sample pretreatment consists of a single extraction with a pH 2.5 phosphate buffer, centrifugation and dilution. For the spectrophotometric assay, the fourth derivative of the absorbance was used which gave satisfactory results in terms of accuracy (mean recovery 99.7%) and precision (mean RSD 3.4%). The electrophoretic experiments were carried out using the shortest effective length of the capillary (8.5 cm) in order to obtain a very rapid separation of reboxetine and dibenzepine used as the internal standard. Using a pH 2.5, 50 mM phosphate buffer as the background electrolyte, each analysis lasted less than 2.5 min. Accuracy (101.3%) and precision (1.5%) were very good.

p120(cat) Delocalization in cell lines of oral cancer

p120(cat) is a novel component of the catenin family, a cytoplasmic molecule closely associated with the cell-cell adhesion molecule E (epithelial)-cadherin, by forming complexes between the cytoplasmic domain of E-cadherin and the cytoskeleton. Recent studies suppose a role for this molecule in human cancers and to date none report its expression in oral squamous cell carcinomas (SCCs). The goal of this study was to evaluate the role of this protein in the oral carcinogenetic process. A linked streptavidin-biotin-alkaline phosphatase technique was used to examine the immunoreactivity and cellular localisation of p120(cat) in five oral epithelial cell lines (NCTC 2544, normal and immortalized keratinocytes; KB, a poorly differentiated SCC cell line; OSC 20, a well differentiated oral SCC cell line; CAL 33 and CAL 27, moderately differentiated oral SCC cell lines) and 10 normal oral epithelium biopsies.

RESULTS

As already reported for E-cadherin, beta- and gamma-catenin, p120 expression showed a homogeneous membranous localization in normal oral specimens. The intensity of staining for p120 progressively increased from basal and parabasal layers toward the intermediate spinous layer. No staining for p120 was observed in the upper layer. NCTC showed a membranous positivity. OSC 20, CAL 33 and CAL 27 showed a membranous positivity, even if polarized to cell-cell adhesion sites, in 40-50% of cells. OSC 20, CAL 33 and CAL 27 cells showed also a cytoplasmic delocalization. All positive KB cells showed a prevalent cytoplasmic staining and 10% of these cells showed a nuclear delocalization. In cancer cells, p120 showed an inverse relationship with the degree of differentiation for a progressive displacement of the signal toward the cytoplasm or nucleus in dedifferentiated cells. In conclusions, this nuclear delocalization for p120 could suppose its potential involvement in signalling and cancer transformation.

Interaction between bcl-2 and P53 in neoplastic progression of basal cell carcinoma of the head and neck

BACKGROUND

Basal cell carcinoma (BCC) is the most frequent tumor of the human skin and generally shows a favourable clinical behaviour. However, a percentage of BCC grows aggressively, infiltrating contiguous structures, sometimes giving distant metastases.

MATERIALS AND METHODS

Bcl-2 and p53 protein expression was studied immunohistochemically in 60 cases of BCC (30 non-aggressive, BCC1 and 30 aggressive cases, BCC2) of the head and neck region with a complete clinical follow-up.

RESULTS

All the BCC1 showed distinct cytoplasmic staining for bcl-2. The intensity of staining ranged from intermediate to high, with only three cases showing low positivity. Among BCC2, none of the 30 cases showed positivity for bcl-2. Bcl-2 expression was directly correlated with the BCC1 sub-type and a favourable clinical follow-up (p<0.01). Among BCC1, 27 cases were found negative for p53 protein expression while 3 exhibited only a low immunoreactivity. Among BCC2, 11 out of 30 cases showed an intermediate immunoreactivity, and 18 out of 30 exhibited high positivity for p53 protein. The expression of p53 protein correlated inversely with cellular differentiation (p<0.01).

CONCLUSION

From the analysis of these results it is reasonable to consider bcl-2 and p53 protein expression as useful discriminating prognostic factors in the evaluation of BCCs of the head and neck region. In fact, the finding of clones expressing bcl-2 in a case of BCC may be indicative of an "indolent" cellular neoplastic phenotype. In other words, bcl-2 could be used as a "clonal marker" of a still favourable clinical behaviour. Conversely, the partial or complete loss of bcl-2-bearing neoplastic clones during histological transformation, with the appearance of clones expressing p53 protein in a BCC could be considered a hallmark of transition from a low-to high-grade malignancy, characterized by the emergence of cellular clones with a more aggressive phenotype, responsible for worse clinical behaviour.

Enantioseparations by capillary electrochromatography

The review summarizes recent developments in enantioseparations by capillary electrochromatography (CEC). Selected fundamental aspects of CEC are discussed in order to stress those features which may allow the success of this technique in the competitive field of enantioseparations. In addition, the comparative characteristics of the different modes of chiral CEC and the stationary phases are presented. The effects of the characteristics of the stationary and liquid phases and operational conditions on the separation results are discussed. Finally, some future trends are briefly addressed.

Chiral analysis of UV nonabsorbing compounds by capillary electrophoresis using macrocyclic antibiotics: 1. Separation of aspartic and glutamic acid enantiomers

Glycopeptide antibiotics, namely vancomycin or teicoplanin, were evaluated in capillary electrophoresis for the analysis of UV nonabsorbing compounds such as aspartic and glutamic acid enantiomers. Electrophoretic runs were performed in laboratory-made polyacrylamide-coated capillaries using the partial filling-counter current method in order to avoid the presence on the detector path of the absorbing chiral selector. The background electrolyte consisted of an aqueous or aqueous-organic buffer in the pH range of 4.5-6.5 of sorbic acid/histidine and the appropriate concentration of chiral selector. Several experimental parameters such as antibiotic concentration and type, buffer pH, organic modifier, type and concentration of absorbing co-ion (for the indirect UV detection) were studied in order to find the optimum conditions for the chiral resolution of the two underivatized amino acids in their enantiomers. Among the two investigated chiral selectors, vancomycin resulted to be the most useful chiral selector allowing relatively high chiral resolution of the studied compounds even at low concentration. The optimized method (10 mM sorbic acid/histidine, pH 5, and 10 mM of vancomycin) was used for the analysis of real samples such as teeth dentine and beer.

Simultaneous determination of reduced and oxidized glutathione in peripheral blood mononuclear cells by liquid chromatography-electrospray mass spectrometry

We developed a sensitive and specific liquid chromatography-electrospray mass spectrometric (HPLC-ESI-MS) assay for the simultaneous determination of reduced and oxidized glutathione (GSH and GSSG) in peripheral blood mononuclear cells (PBMC). Following derivatization with N-ethylmaleimide to prevent GSH auto-oxidation, addition of thiosalicylic acid as internal standard, and protein precipitation with cold acetonitrile, the samples were injected into a diol column, eluted with acetonitrile-1% aqueous acetic acid (25:75) and detected by the ESI-MS system. The optimized method exhibited a good detection limit for both analytes (0.01 and 0.05 microM for GSH and GSSG, respectively). Good linearity was reached in the 0.01-20 microM range for GSH and 0.05-20 microM for GSSG. The mean recoveries of GSH and GSSG were 98.5-100.6% and 105.8-111.5%, respectively. The run-to-run repeatability for retention time and peak area was RSD% 0.06 and 1.75 for GSH and 0.18 and 2.50 for GSSG. The optimized method was applied to GSH and GSSG assay in PBMC analyzing 20 healthy individuals.

Use of vancomycin silica stationary phase in packed capillary electrochromatography. II. Enantiomer separation of venlafaxine and O-desmethylvenlafaxine in human plasma

A capillary electrochromatography method, using vancomycin chiral stationary phase packed capillary, was optimized for the simultaneous chiral separation of the antidepressant drug venlafaxine and its main active metabolite O-desmethylvenlafaxine. Simultaneous baseline enantiomeric separation of the two compounds was obtained using a mobile phase composed of 100 mM ammonium acetate buffer pH 6/water/acetonitrile (5:5:90, v/v). The electrokinetic injection for sample introduction provided a limit of quantitation for both the compounds of 0.05 microg/ml racemate concentration suitable for the analysis of venlafaxine and metabolite in biological samples. The acetonitrile mobile phase concentration was found to modulate the analytes elution times, the enantiomeric resolution and the efficiency of the separation. The column was tested for repeatability and linearity showing RSD values (%) in the range of 0.13-0.24, 2.47-3.66 and 1.35-2.50 for migration time, sample/internal standard peak area ratio and enantiomeric resolution, respectively and correlation coefficients higher than 0.9990. The method was applied to the analysis of clinical samples of patients under depression therapy showing a stereoselective metabolism for venlafaxine.

Rapid capillary electrophoretic method for the determination of clozapine and desmethylclozapine in human plasma

A rapid and sensitive high-performance capillary electrophoretic method for the determination of clozapine and its main metabolite desmethylclozapine in human plasma was developed. The separation of the two analytes was carried out in an untreated fused-silica capillary [33 cm (8.5 cm effective length) x 50 microm I.D.] filled with a background electrolyte at pH 2.5 containing beta-cyclodextrin. Baseline separation of clozapine and desmethylclozapine was recorded in less than 3 min. An accurate sample pretreatment by means of solid-phase extraction and subsequent concentration allows for reliable quantitation of clozapine in the plasma of schizophrenic patients under treatment with the drug. The method showed good precision (mean RSD = 4.0%) as well as satisfactory extraction yields (approximately 88%) and a good sensitivity (limit of quantitation = 0.075 microg ml(-1), limit of detection = 0.025 microg ml(-1)).

Use of vancomycin silica stationary phase in packed capillary electrochromatography I. Enantiomer separation of basic compounds

Chiral separation of basic compounds was achieved by using 75 or 100 microm ID fused-silica capillaries packed with a vanoomycin-modified diol silica stationary phase. The capillary was firstly packed for about 12 cm with a slurry mixture composed of diolsilica (3:1) then with the vancomycin modified diol-silica (3:1) (23 cm), and finally with diol-silica (3:1) for about 2 cm. Frits were prepared by a heating wire at the two ends of the capillary; the detector window was prepared at 8.5 cm from the end of the capillary where vancomycin was not present. The influence of the mobile phase composition (pH and concentration, organic modifier type and concentration) on the velocity of the electroosmotic flow, chiral resolution and enantioselectivity was studied. Good enantiomeric resolution was achieved for atenolol, oxprenolol, propranolol, and venlafaxine using a mobile phase composition of 100 mM ammonium acetate solution (pH 6)/water/acetonitrile (5:5:90 v/v/v) while for terbutaline a mixture of 5:15:80 v/v/v provided the best separations. The use of methanol instead of acetonitrile caused a general increase of enantiomer resolution of the studied compounds together with a reduction of efficiency and detector response. However, the combination of acetonitrile and methanol in the mobile phase (as, e.g., 10% methanol and 80% acetonitrile) allowed to improve the enantiomer resolution with satisfactory detector response.

Separation of multicomponent mixtures of 2,4-dinitrophenyl labelled amino acids and their enantiomers by capillary zone electrophoresis

The use of capillary zone electrophoresis (CZE) for the separation of a group of 33 2,4-dinitrophenyl labeled amino acids (DNP-AA), including DNP-AA racemates, DNP-L-AA enantiomers and achiral DNP-AAs, was investigated. Alpha-, beta- and gamma-cyclodextrins (CDs) and their derivatives (hydroxypropyl derivatives of alpha-, beta- and gamma-CDs, polymeric beta-CD and 6A-methylamino-beta-cyclodextrin (MA-beta-CD)) served as complexing agents and chiral selectors in this investigation. Although native alpha- and gamma-CDs and their derivatives influenced the effective mobilities of the studied DNP-AAs in different ways, they generally failed to resolve enantiomers of the individual DNP-AAs. On the other hand, beta-CD and all of its derivatives were found to be effective in this respect. Of these, the best results were achieved with a positively charged MA-beta-CD and this chiral selector resolved enantiomers of ten DNP-AA racemates available for this study. However, a complete resolution of these enantiomers in one CZE run required that the effect of the chiral selector be complemented by complexing effects of polyvinyl pyrrolidone (PVP) or gamma-CD. Complexing and chiral recognition capabilities of MA-beta-CD combined with complexing effects of gamma-CD and PVP provided separating conditions suitable for the CZE separations of multicomponent mixtures of DNP-AAs with preserved resolutions of the enantiomers. For example, a mixture consisting of 43 DNP-AA constituents was resolved using an MA-beta-CD/gamma-CD combination with three peak overlaps.

Capillary electrochromatography and capillary electrochromatography-electrospray mass spectrometry for the separation of non-steroidal anti-inflammatory drugs

In this study capillary electrochromatography (CEC) was utilized for the separation of ten non-steroidal anti-inflammatory drugs (NSAIDs). Experiments were carried out in a commercially available CE instrument using a packed capillary with RP-18 silica particles where the stationary phase completely filled the capillary. The mobile phase consisted of a mixture of ammonium formate buffer pH 2.5 and acetonitrile. Selectivity and resolution were studied changing the pH and the concentration of the buffer, the acetonitrile content mobile phase and the capillary temperature. The optimum experimental conditions for CEC separation of the studied drug mixture were found using 50 mM ammonium formate pH 2.5-acetonitrile (40:60) at 25 degrees C. The CEC capillary was coupled to an electrospray mass spectrometer for the characterization of the NSAIDs. A mobile phase composed by the same buffer but with a higher concentration of acetonitrile (90%) was used in order to speed up the separation of analytes.

The human multidrug resistance gene (MDR-1): immunocytochemical detection of its expression in oral SCC

A large number of oral cancer patients show poor or partial response to chemotherapy and the mechanisms are poorly understood. At present, an MDR-1 product, the P-170 glycoprotein, is the best known of the P-170 family and is involved in resistance to natural product-based chemotherapeutics, including taxanes, anthracyclines, vinca alkaloids, podophyllotoxins and camptothecins. Although several reports suggest that P-170 is clinically relevant in haematological malignancies, its role in solid tumours is not well understood. Its overexpression has been found to be correlated with the poor outcome observed in patients treated with chemotherapy and presenting drug resistance. The aim of this study was to detect the protein expression patterns of MDR-1 product by immunohistochemistry in formalin-fixed-paraffin-embedded tissues. For these reasons, 30 oral SCC and 6 healthy oral mucosa specimens were tested with anti-P-170 antibodies using standard streptavidin-biotin-peroxide technique. Immunohistochemistry demonstrated that 4 cases (66.6%) of normal oral mucosa and 24 cases (80%) of oral SCC showed positivity. Four cases (13.4%) showed strong positivity in tumour areas and complete negativity in normal epithelial cells adjacent to the tumour. No staining was observed in stromal structures, with the exception of the lymphocytic compartment that showed a strong staining as reported in literature for CD56+ and CD8+ cells. Four G1 tumours (33%) and 2 G3 tumour (33%) showed strong positivity in areas with a higher degree of differentiation. P-170 positivity in normal epithelial cells of smoker patients, in differentiated area of neoplasia and negativity or zonal positivity in undifferentiated area of tumour suggested that activation of the MDR-1 gene or selection of intrinsically multidrug resistance neoplastic cells may occur at early stages of tumorigenesis of oral cancers, before the real evidence of cellular transformation. Thus the contact with possible chemical carcinogens, such as those of tobacco smoke, may induce activation of MDR-1 gene. This study was conducted only on untreated carcinomas so for this reason it cannot indicate the real incidence of acquired multidrug resistance. The data of MDR-1 product expression by immunohistochemistry in oral SCC might suggest that an overexpression of this protein could constitute a hallmark of potential more aggressive phenotype for this type of neoplasia and a rapid method for pre-screening tumours for a constitutive multidrug resistance in order to orientate the cancer treatment.

Enantiomeric separation of dihydroxyphenylalanine (DOPA), methyldihydroxyphenylalanine (MDOPA) and hydrazinomethyldihydroxyphenylalanine (CDOPA) by using capillary electrophoresis with sulfobutyl ether-beta-cyclodextrin as a chiral selector

Capillary electrophoresis (CE) was successfully applied to the enantiomer resolution of racemic structurally related compounds, namely dihydroxyphenylalanine (DOPA), methyldihydroxyphenylalanine (MDOPA) and hydrazinomethyldihydroxyphenylalanine (CDOPA). The chiral resolution was performed in an untreated fused-silica capillary by using a phosphate buffer at pH 2.5 or 3.0 supplemented with sulfobutylated beta-cyclodextrin (SBE-CD). Resolution was strongly influenced by the concentration of the chiral selector added to the background electrolyte. In fact, 2-5 mM of SBE-CD enabled the resolution of DOPA and MDOPA enantiomers, while CDOPA optical isomers were resolved by using either 0.5 mM or 6-20 mM of SBE-CD. The latter separation conditions (reversed polarity mode) made it possible to obtain inversion of migration order.

Simultaneous stereoselective analysis of venlafaxine and O-desmethylvenlafaxine enantiomers in clinical samples by capillary electrophoresis using charged cyclodextrins

Capillary electrophoresis (CE) was used for the simultaneous chiral determination of venlafaxine (Vx), a new antidepressant drug and its main active metabolite. O-desmethyl venlafaxine (ODV). Among the charged cyclodextrins (CD) tested, phosphated gamma-CD was the most appropriate. Resolution of Vx and ODV was obtained with 50 mM phosphate buffer (pH 2.5) containing 20 mg/ml of phosphated gamma-CD. After optimisation of the method (including robustness), validation was carried out. Vx and ODV concentrations, as well as the enantiomeric ratio, were investigated in clinical samples. Chiral determination of Vx and ODV was performed after a simple liquid-liquid extraction (LLE). In the tested concentration range (25-500 ng/ml), coefficients of correlation were superior to 0.996. Within-day and between-day accuracy and precision were determined at three different concentrations for each enantiomer. Analyses of clinical samples (n = 16) exhibited non-racemic ratios for Vx and ODV, which suggests a stereoselective metabolism in humans.

Separation and identification of etodolac and its urinary phase I metabolites using capillary electrochromatography and on-line capillary electrochromatography-electrospray ionisation mass spectrometry coupling

Capillary high-performance liquid chromatography (capillary HPLC), pressure-assisted capillary electrochromatography (pCEC) and capillary electrochromatography (CEC) were performed in the same capillary packed with 5 microm octadecylsilica (C18) as stationary phase. These three separation modes were compared from the viewpoint of peak efficiency and separation selectivity in order to critically evaluate the advantages which CEC may offer compared to capillary HPLC for the solution of practical biomedical problems. The separation of the non-steroidal anti-inflammatory drug etodolac (ET, 1) and its phase I metabolites, 6-hydroxy etodolac (6-OH-ET, 2), 7-hydroxy etodolac (7-OH-ET, 3) and 8-(1'-hydroxyethyl) etodolac (8-OH-ET, 4) was selected as an example. Baseline separation of all compounds was achieved in different modes and conditions. The effect of pure electrophoretic separation mechanism on the overall separation selectivity observed in CEC has been shown. A high electroosmotic flow (EOF) was observed in C18 packed capillary even at pH 2.5 in various buffers. Furthermore, these separations were coupled on-line with electrospray ionisation mass spectrometry (ESI-MS) and the parent drug and its metabolites were identified in urine. For the coupling of CEC with ESI-MS a laboratory-made electrophoretic device was used in order to overcome some technical disadvantages of commercial instrumentation.

Analysis of hydroquinone and some of its ethers by using capillary electrochromatography

Capillary electrochromatography (CEC) was used for the analysis of relevant compounds in cosmetic preparation. Hydroquinone (HQ) and some of its ethers (methyl-, dimethyl-, benzyl-, phenyl-, propyl-HQ derivatives) were analyzed by using an octadecylsilica (ODS) stationary phase packed in fused-silica capillary (100 microm I.D.; 30 cm and 21.5 cm total and effective lengths, respectively). 20 mM Ammonium acetate pH 6-acetonitrile (50-70%) were the mobile phases used for the experiments. The acetonitrile (ACN) content strongly influenced the resolution of the studied compounds as well as the efficiency and the retention factor. Baseline resolution for the studied analytes was achieved at both the lowest and the highest percentage of ACN, the last one providing the shortest analysis time. Mobile phase containing 70% of ACN was therefore used for the analysis of an extract of skin-toning cream declared to contain HQ. Good repeatability of both retention times, peak areas and peak areas ratio (Asample/Ainternational standard) was found. The calibration graphs were linear in the concentration range studied (5-90 microg/ml) with correlation coefficients between 0.9975 and 09991. The analysis of the cosmetic preparation revealed the presence of HQ (1.72%, w/w) and of two additional peaks (not identified).

Quality control of benserazide-levodopa and carbidopa-levodopa tablets by capillary zone electrophoresis

In modern practice, the treatment of Parkinson's disease and syndrome is carried out using pharmaceutical formulations containing a combination of levodopa and a decarboxylation inhibitor (carbidopa or benserazide). Two pharmaceutical formulations were quantified by capillary zone electrophoresis using two procedures which differed only in the kind of background electrolyte used. One procedure used a 25 mM phosphate buffer, pH 2.5, while the second one used a 25 mM borate buffer, pH 8.5. The electrophoretic analysis was carried out using an uncoated fused- silica capillary, a separation voltage of 20 kV with currents typically less than 60 microA, and spectrophotometric detection at 205 nm. Calibration curves were performed for levodopa (concentration range 1-100 microg/mL), for carbidopa and benserazide (1-50 microg/mL), and the plots of the peak area versus concentration were found to be linear with a correlation coefficient better than 0.9990. Satisfactory results were obtained when commercial tablets were analyzed in terms of accuracy (98-102%), repeatability (0.6-2.0%), and intermediate precision (1.1-2.6%).