[Features of the periodontal pathology at patients with metabolic syndrome].

The purpose of this article is to familiarize readers on the relationship between metabolic syndrome and periodontitis, as well as common pathogenetic processes underlying these diseases. The data of modern researches, devoted to the correlation of lesions of periodontal and systemic diseases associated with metabolic syndrome. In the article analyzed also the data of the original study of the interaction of periodontitis and metabolic syndrome, which also used special methods of examination like Doppler ultrasound microcirculatory vasculature of the periodontal tissues and ultrasound densitometry. The possible methods of diagnostics of a condition of periodontal tissues in patients with metabolic syndrome are considered. Conclusions about the relationship of each component of metabolic syndrome with periodontitis are made.

Effect of dialyzed saliva on human enamel demineralization.

BACKGROUND: Saliva is supersaturated with respect to calcium and phosphate ions. Salivary ions may well play a role in the subsequent adsorption of proteins and consequently in the formation of the acquired enamel pellicle. Among several biological functions, the enamel pellicle forms a selectively permeable barrier that regulates demineralization processes. AIM: The aim of this study was to evaluate the importance of salivary proteins when adsorbed on enamel surface and the resultant protective effect against demineralization without the presence of salivary ions. METHODS: Enamel surfaces were coated with whole saliva, parotid saliva, dialyzed whole saliva or dialyzed parotid saliva (molecular weight cutoff 1 kDa). Adsorption was allowed to proceed for a period of 2 h. Enamel specimens were then washed with deionized water and immersed into a demineralization solution of pH 4.5 for 12 days. This solution was used to measure the amount of calcium and phosphate released from enamel specimens after the demineralization period. RESULTS: All coated specimen groups showed a significantly higher protection than those not coated with any type of saliva. In addition, undialyzed saliva (whole saliva and parotid saliva) was more effective in protecting the enamel against demineralization than dialyzed saliva. CONCLUSION: The present investigation indicates that the ionic composition of saliva can amplify the demineralization protection effect by reducing acid-induced enamel demineralization. Moreover, a protective effect of salivary proteins without presence of ions was demonstrated in this study.

The effect of systemically administrated zoledronic acid on the osseointegration of dental implants.

OBJECTIVE: The aim of conducting this study was to evaluate the effect of zoledronic acid (ZA) on the new bone formation (NBF) after the insertion of a titanium dental implant, which is very popular treatment in dentistry. STUDY DESIGN: Twelve New Zealand white rabbits were used in this study. The rabbits were divided in two groups. ZA was systemically administered to the study group. Titanium implants were placed to the left and right tibias of the rabbits. RESULTS: The data from the ZA group revealed a statistically significant increase in the bone mineral content and the bone mineral density. A non-decalcified histomorphometric examination conducted on the study group revealed a significant increase of NBF and bone-implant contact (BIC) at 2 and 4 weeks. CONCLUSION: A single dose of systemic ZA administration increases the rate of NBF and augments the quality of the bone.

Specific volume and compressibility of bilayer lipid membranes with incorporated Na,K-ATPase.

Ultrasound velocimetry and densitometry methods were used to study the interactions of the Na,K-ATPase with the lipid bilayer in large unilamellar liposomes composed of dioleoyl phosphatidylcholine (DOPC). The ultrasound velocity increased and the specific volume of the phospholipids decreased with increasing concentrations of protein. These experiments allowed us to determine the reduced specific apparent compressibility of the lipid bilayer, which decreased by approx. 11% with increasing concentrations of the Na,K-ATPase up to an ATPase/DOPC molar ratio = 2 × 10⁻4. Assuming that ATPase induces rigidization of the surrounding lipid molecules one can obtain from the compressibility data that 3.7 to 100 times more lipid molecules are affected by the protein in comparison with annular lipids. However, this is in contradiction with the current theories of the phase transitions in lipid bilayers. It is suggested that another physical mechanisms should be involved for explanation of observed effect.

Accommodating brightness and exposure levels in densitometry of stained polyacrylamide electrophoresis gels.

Flatbed scanner densitometers can be operated under various illumination and recording exposure levels. In this work, we show that optical density measurement accuracy, sensitivity, and stability of stained polyacrylamide electrophoresis gel densitometry are crucially dependent on these two factors (brightness and exposure level), notwithstanding that the source is monochromatic, spatially uniform, and the measurements are made using an accurately calibrated step wedge in tandem. We further outline a method to accommodate the intensity deviations over a range of illumination and exposure levels in order to maintain sensitivity and repeatability in the computed optical densities. Comparisons were also made with results from a commercial densitometer.

Role of H2O2 and cell wall monoamine oxidases in germination of Vigna radiata seeds.

Plant cell wall expresses monoamine oxidases (MAOs) that catalyze oxidation of secreted amines and produce H2O2 in the process. The H2O2, so produced is used by cell wall peroxidases for lignification of cell wall or for plant defense. The natural substrates for these MAOs are elusive, but polyamines and certain catecholamines have been proposed as candidates. Reactive oxygen species are also known to act as signaling molecules controlling plant metabolism. Mungbean (Vigna radiata) has long served as the plant model of choice while studying molecular programs followed during germination and seed development. In this study, we tested the effect of externally added MAO substrates epinephrine and H2O2 on storage protein mobilization in germinating seeds of Vigna radiata. The seeds were imbibed in the presence of 50 microM epinephrine and 10 microM H2O2. These low concentrations of the two compounds were used to exclude direct effects on proteolysis and were arrived at after testing a range of the two and choosing the most effective concentration. These seeds showed 11% and 7% decrease in fresh weight respectively, indicating greater storage mobilization and a corresponding 19% and 46% increase in axis length as compared to untreated seeds. Soluble protein in seeds treated with epinephrine and H2O2 decreased significantly by 34% and 33% as compared to untreated seeds. Electrophoretic analysis of seed proteins revealed a startling and selective depletion of storage proteins in treated seeds. The results indicated a clear involvement of H2O2 in storage protein mobilization in the cotyledons. We propose that H2O2 generated within cell walls of seeds serves as a signaling molecule guiding germination events, including protein reserve mobilization.

Analysis of Product Quality of Complex Polymeric IgM Produced by CHO Cells.

Immunoglobulin M (IgM) antibodies are considered as promising biopharmaceutical drugs in the future despite recombinant production is quite challenging as incomplete polymer formation or nucleic acid adherence can decrease the quality of the IgM preparation. Therefore, we defined densitometric and chromatographic methods as suitable tools to analyze the polymer distribution and the remaining nucleic acid content after initial IgM purification. Additionally, the quality of the glycosylation pattern is an important parameter for biological safety and efficacy.

Evaluation of voxel values in mandibular cancellous bone: relationship between cone-beam computed tomography and multislice helical computed tomography.

OBJECTIVE: Measurements of bone density in designed sites are important in presurgical imaging for dental implant treatment. However, the pixel or voxel values obtained from cone-beam computed tomography (CT) images are not absolute values. Hence, the relationship between voxel values obtained from cone-beam CT with a limited-volume exposure field and a flat panel detector and bone mineral densities (BMDs) obtained from multislice CT was evaluated in the mandible. MATERIAL AND METHODS: A total of 16 (four males and 12 females) patients who had undergone imaging for mandibular dental implant treatment using cone-beam CT with Alphard VEGA and multislice CT were enrolled in this investigation. Cross-sectional images of cone-beam and multislice CT were reconstructed, and values of regions of interest (ROIs) in images were calculated. RESULTS: A high-level correlation between voxel values of cone-beam CT and BMDs of multislice CT was observed (r=0.965). CONCLUSION: It was suggested that voxel values of mandibular cancellous bone in cone-beam CT could be used to estimate bone density.

Comparative radiopacity of bonding agents.

PURPOSE: The present study was undertaken to determine the content and the constituent elements of inorganic fillers as well as the radiopacity of 15 recently introduced bonding agents and to compare their radiodensities with those of enamel and dentin by using a transmission photodensitometer. MATERIALS AND METHODS: The content of inorganic fillers was determined by the ashing method. In addition, x-ray microanalysis was used to identify the constituent elements of the inorganic fillers. In the measurement of the radiopacity, specimens 10 mm in diameter and 0.9 mm in thickness were fabricated from the 15 different bonding agents (n = 3 each) for a total of 45 specimens. Human premolars were longitudinally sectioned into 1.0-mm-thick slices to include both enamel and dentin, then ground to final thickness of 0.9 mm. The optical densities of enamel, dentin, the bonding agents, and an aluminum (Al) step wedge were obtained from radiographic images by transmission photodensitometry. The Al equivalent (mm) for each material was calculated by using the linear regression equation of the log of the normalized optical density and Al thickness (mm) obtained from the step wedge. A linear regression of the logarithm of the normalized optical density and Al thickness (mm) was plotted. RESULTS: The inorganic filler content ranged from 0.0 wt% to 43.5 wt%. Silicon and aluminum were the main constituent elements of the inorganic fillers; however, the resins contained different kinds of inorganic fillers. These elements have high and low atomic numbers. The surface reaction type pre-reacted glass-ionomer (S-PRG)-filled bonding agent (FII) had a filler content of 43.5 wt% and contained B, Si, Sr, Na, F and Al as its elemental constituents. The relative radiopacities expressed as equivalent thickness of Al were ranked ordinally. Fourteen of the 15 adhesive resins had radiopacity values that fell below that value for dentin, whereas the FII resin showed a radiopacity that was equal to or greater than that of dentin but below that of enamel (p < 0.05). CONCLUSION: The radiopacity of bonding agents depended on their filler content and the presence of heavier atoms of elements in the filler.

Estimation of wood stiffness and strength properties of hybrid larch by near-infrared spectroscopy.

This work was undertaken to investigate the feasibility of near-infrared (NIR) spectroscopy for estimating wood mechanical properties, i.e., modulus of elasticity (MOE) and modulus of rupture (MOR) in bending tests. Two sample sets having large and limited density variation were prepared to examine the effects of wood density on estimation of MOE and MOR by the NIR technique. Partial least squares (PLS) analysis was employed and it was found that the relationships between laboratory-measured and NIR-predicted values were good in the case of sample sets having large density variation. MOE could be estimated even when density variation in the sample set was limited. It was concluded that absorption bands due to the OH group in the semi-crystalline or crystalline regions of cellulose strongly influenced the calibrations for bending stiffness of hybrid larch. This was also suggested from the result that both alpha-cellulose content and cellulose crystallinity showed moderate positive correlation to wood stiffness.

Efficacy of clinical methods to assess jawbone tissue prior to and during endosseous dental implant placement: a systematic literature review.

PURPOSE: To evaluate the evidence for the diagnostic accuracy of clinical methods to assess bone density, quantity, or quality prior to and during dental implant placement. MATERIALS AND METHODS: A PubMed literature search with specific indexing terms and a hand search were made. From the retrieved titles and abstracts, 3 reviewers selected publications on the basis of predetermined inclusion and exclusion criteria. Data were extracted from the selected publications using a protocol. Original studies were interpreted with the aid of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. RESULTS: The literature search yielded 145 titles and abstracts, of which 71 were selected and read in full text. Seven studies were judged relevant. In 1 study, no method was presented as the test method. In 6 studies, the results of the test method were compared to those of a reference method. However, only 1 study presented the results in terms of percentage of correct diagnoses. In that study, the use of periapical radiography together with reference images yielded correct assessment of the trabecular pattern of the mandible in 3 categories in 58% of the sites. The kappa index of interobserver agreement was 0.35 and intraobserver agreement was 0.67. Corresponding kappa values for 4 classes of bone quality presented by Lekholm and Zarb were 0.33 and 0.43, respectively. No study examined the accuracy of the method originally described by Lekholm and Zarb. CONCLUSION: The evidence for the efficacy of clinical methods to assess jawbone tissue prior to and during endosseous dental implant placement is sparse. This emphasizes the need for studies that incorporate accepted methodologic criteria for diagnostic efficacy.

Bone density assessments of dental implant sites: 3. Bone quality evaluation during osteotomy and implant placement.

PURPOSE: In previous publications of this series of studies on human cadaver jaws, bone densities were assessed and compared using subjective evaluation, conventional computed tomography (CT), and cone-beam computed tomography (CBCT). The aim of this study was to compare subjective bone quality during osteotomy and implant insertion resistance torque to noninvasive subjective and objective radiographic bone density assessments. MATERIALS AND METHODS: Forty-two designated implant sites were selected. Self-tapping implants were inserted into these sites. The operator subjectively rated the bone density during the osteotomy procedure. Resistance torque was recorded during insertion of the implants. RESULTS: Subjective drilling resistance was modestly correlated to subjective radiographic density evaluation (Lekholm and Zarb; Spearman's rho of 0.53, P < .001). Subjective drilling resistance compared to the bone density in Hounsfield units (HU) obtained using CT and CBCT showed correlation coefficients of 0.61 and 0.59, respectively (P < .001). Significant overlap of density values was found for adjacent drilling ratings. On average, a difference in bone density of 180 HU was required to identify differences between drilling resistance groups. Comparisons of 2 implant insertion resistance torque variables (highest reading and regression slope of available readings) with CT and CBCT HU showed correlation coefficients of 0.61 to 0.63 (P < .01). CONCLUSION: Insertion torque resistance was modestly correlated with objective CT and CBCT measurements of bone density. The merit of these assessments of cadavers awaits clinical study.

Ultrasonic characterization of the mechanical properties and polymerization reaction of acrylic-based bone cements.

In this investigation the pulse-echo technique was validated as a method that could be used to monitor the complete polymerization of acrylic bone cement in a surgical theatre. Currently, orthopaedic surgeons have no objective method to quantify the state of cure of bone cement as it progresses through its polymerization cycle. Clear benefits of the pulse-echo technique are that it is easy to use, non-invasive, and non-destructive. Furthermore, the test results were found to be highly reproducible with minor deviations. Three proprietary cements were used to confirm the validity of the technique; CMW Endurance, Palacos R and Simplex P. The results showed that the acoustic properties of bone cement clearly demonstrated a relationship with the different stages of polymerization, and in particular with the transitions between the waiting, dough, and setting phases. Additionally, the cure time of the poly(methyl methacrylate) cements consistently correlated with the attainment of 75 per cent of the average maximum velocity of sound value. The measured cure times concurred with the ISO and ASTM standards. Moreover, measurements of the final sound velocity and broadband ultrasonic attenuation correlated strongly with the density and mechanical properties of the cured bone cement samples.

Spray-dried microparticles containing polymeric nanocapsules: formulation aspects, liquid phase interactions and particles characteristics.

Up to now, the full potential of polymer-based nanoparticles is not yet exploited because of a lack of stability when conserved in aqueous medium. The present paper reports the water elimination from nanocapsules (NC) dispersions by means of the spray-drying technique with the aim to achieve dried solid forms of interest using colloidal silicon dioxide as drying auxiliary. The influence of formulation parameters on the suspension behaviour and on the powders characteristics was also evaluated. Our findings demonstrated that the mixing protocol, the concentrations of both NC and silica are crucial parameters that affect the feed behaviour and the spray-dried particles characteristics. Interactions occurring in the feed are directed by hydrogen bounds and were more sensitive to the silica concentration than that of NC as evidenced by rheological measurements. The NC are entrapped within solid dried matrixes following their interaction with silica particles in the feed. SEM analyses of the obtained powders showed spherical separated microparticles formed by the association of NC and silica when they are mixed at adequate concentrations in the feed before spray-drying. On the other hand, fused agglomerated particles presenting NC at their surface, characterised by irregular shapes and a strong adhesiveness were prepared when the silica concentration was not sufficient. The surface composition of the spray-dried powders was investigated using the ESCA technique and revealed the NC exclusion from the surface to obtain powders suitable for further handling.

Stability-indicating methods for the determination of disopyramide phosphate.

Four methods were developed for the determination of intact disopyramide phosphate in the presence of its degradation product. In the first and second methods, third-derivative spectrophotometry and first derivative of the ratio spectra were used. For the third-derivative spectrophotometric method, the peak amplitude was measured at 272 nm, while for the derivative ratio spectrophotometric method, disopyramide phosphate was determined by measuring the peak amplitude at 248 and 273 nm. Both methods were used for the determination of disopyramide phosphate in the concentration range 12.5-87.5 microg/mL, with corresponding mean recovery 100.8 +/- 0.7% for the first method and 99.9 +/- 0.7% and 99.6 +/- 0.7% for the second method at 248 and 273 nm, respectively. In the third method, an ion selective electrode (ISE) was fabricated using phosphotungstic acid as an anionic exchanger, PVC as the polymer matrix, and dibutylsebacate as a plasticizer. The ISE was used for the determination of disopyramide phosphate in pure powder form in the concentration range 10(-2)-10(-5) M. The slope was found to be 58.5 (mV/decade), and the average recovery was 99.9 +/- 1.6%. The fourth method depended on the quantitative densitometric determination of the drug in concentration range of 0.25-2.5 microg/spot using silica gel 60 F245 plates and ethyl acetate-chloroform-ammonium hydroxide (85 + 10 + 5, v/v/v) as the mobile phase, with corresponding mean accuracy of 100.3 +/- 1.1%. The 4 proposed methods were found to be specific for disopyramide phosphate in presence of up to 80% of its degradation product for the spectrophotometric methods, 90% of its degradation for the densitometric method, and 40% for the ISE method. The 4 proposed procedures were successfully applied for the determination of disopyramide phosphate in Norpace capsules. Statistical comparison between the results obtained by these methods and the official method of the drug was done, and no significant differences were found.

Dual polarization interferometry size and density characterisation of DNA immobilisation and hybridisation.

Investigation of nucleic acid interactions was performed using dual polarization interferometry, a novel approach to elucidating molecular interactions. This paper presents a preliminary study of adsorption of single stranded DNA onto functionalised silicon oxynitride, compared with covalent linkage, and avidin-biotin immobilisation. The effect of probe concentration on hybridisation efficiency was also examined. We found that increasing the electrolyte concentration resulted in a decrease of adsorbed DNA and that capture of a biotinylated duplex DNA on an adsorbed avidin layer resulted in four times fewer molecules per cm(2) than for duplex DNA covalently bound via an amine end terminal. The rate of thickness increase of a biotin probe layer on an adsorbed avidin capture layer increased 10-fold when the probe concentration was increased from 0.1 microM to 1 microM. The close grafting density of the higher concentration probe meant that the immobilised probes were unavailable for hybridisation.

A quantitative and qualitative analysis of bone remodelling around custom uncemented femoral stems: a five-year DEXA follow-up.

BACKGROUND: After total hip replacement bone remodelling is determinant for the implant survival. This study asked whether the immediate postoperative amount and distribution of bone can predict the changes in bone amount and distribution after five years in the case of younger patients with custom uncemented implant. METHODS: We investigated 17 hips with a mean follow-up of 5.1 years. The average patient age at follow-up was 48.5 years. We used immediate postoperative and five-year dual energy X-ray absorptiometry measurements of bone mineral content, density, and projected bone area in seven local zones forming a partition of the upper femur. A correlation was sought between the preoperative variables and the five-year variation. Qualitative bone remodelling was analysed considering each local zone in a density-area plane. Based on geometrical considerations, we introduced an index of structural remodelling, which expresses the preponderance of internal remodelling against external modelling. FINDINGS: The bone mineral content at operation correlated significantly with its relative decrease locally laterally mid-proximally and medially (P<0.01), distally, and globally for the femur (P<0.05). For the bone mineral density, the correlation was significant distally, medially and globally (P<0.05). The bone projected area shows only significant correlation laterally mid-proximally (P<0.01). The index of structural remodelling was significantly positive (P<0.01) in all local zones and was independent of the initial bone amount and structure (P>0.1). INTERPRETATION: High bone mineral content at operation correlates significantly with periprosthetic bone loss after five years in younger patients with cementless custom femoral implant. Independently of the net bone mineral content balance, external modelling is stronger than internal remodelling in all local zones.

Development and validation of a thin-layer chromatographic method for determination of chloramphenicol residues on pharmaceutical equipment surfaces.

A thin-layer chromatographic (TLC) method with densitometric quantitation using the absorption reflectance mode at 280 nm was developed and validated for the determination of chloramphenicol residues in controlling pharmaceutical equipment cleanliness. Simulated samples at residue levels 0.5, 1, and 1.2 mg/m2 were prepared by spreading the calculated amount of chloramphenicol solution on a 10 dm2 stainless steel surface. After evaporation of the solvent, the residue was removed by 2 methanol-wetted cotton swabs, which were then extracted with methanol. The extract was applied on a high-performance TLC (HPTLC) silica gel F254 plate together with standards ranging from 10 to 60 ng. Plates were developed in a horizontal developing chamber from both sides (36 applications per plate) by using n-hexane-ethyl acetate (35 + 65, v/v) as developing solvent. The mean recovery (n=6) at 1 mg/m2 was 95.8%, and the coefficient of variation was 5.8%. The absolute detection limit was 3 ng, and the quantitation limit 10 ng. The method detection limit was 0.3 mg/m2 by swabbing 2.5 dm2 and 0.075 mg/m2 by swabbing 10 dm2. Chloramphenicol was stable on the plate 2 h before and 24 h after development. Additionally, it was stable during 7 days storage on the cotton swabs in the solvent at room temperature and in diluted standard solution stored in darkness at 4 degrees C. The method can be applied to routine control of pharmaceutical equipment cleanliness by sampling from the stainless steel surface areas of 2.5 to 10 dm2, and an acceptable residue limit of 1 mg/m2.

Identification and quantitation of polymyxin B, framycetin, and dexamethasone in an ointment by using thin-layer chromatography with densitometry.

A new thin-layer chromatographic-densitometric method has been developed for rapid identification and quantitative determination of polymyxin B, framycetin, and dexamethasone in a dental ointment. Silica gel 60 and F254 silica gel 60 plates were used for separating antibiotics and dexamethasone acetate, respectively. When determining framycetin and polymyxin B, chromatograms were developed by using 2 mobile phases, namely methanol and methanol-n-butanol-ammonia (25%)-chloroform (14 + 4 + 9 + 12, v/v/v/v/). The densitometric measurements were made at 550 nm after detection with 0.3% ninhydrin solution. Dexamethasone was determined by using the mobile phase cyclohexane-ethyl acetate (2 + 3, v/v) and ultraviolet densitometric recording at 245 nm. The results obtained for individual constituents with the chromatographic-densitometric method demonstrate similar accuracy, relative standard deviation values from 1.49 to 2.47%, and relative error values from 0.02 to 0.81% and are comparable to those obtained with the reference methods.