Clinical evaluation of the oral health status in vascular-type dementia patients. A case-control study

AIM

The aim of this study was to evaluate the oral health status in patients with vascular dementia (VaD). Moreover, the association of the disease severity and the patients' cognitive and functional impairment with the oral findings have been recorded.

METHODS

The study was directed on the study group (86 VaD patients) and the control group (82 healthy volunteers of the same age) from the IRCSS Neurolesi Bonino-Pulejo in Messina, Italy. Cognitive status was evaluated with the MMSE scoring system. Oral parameters, such as decaying, missing, filled teeth (DMFT) index, plaque index (PI), periodontal probing depth (PPD) and bleeding on probing (BOP) were evaluated in all patients. Denture condition and denture-induced stomatitis were also analysed. The frequency of untreated caries, periodontal diseases and missing teeth of the Study Group was significantly higher than in Control Group.

RESULTS

Particularly, VaD patients presented higher number of decayed teeth and deeper periodontal pockets. Decreased cognitive functions in VaD patients have been demonstrated to result in a decline of denture care and increased denture-related mucosal lesions.

CONCLUSION

These results underlined that clinicians should direct high attention to oral hygiene of patients with VaD in order to prevent the evolution of those pathologic dental and periodontal conditions, especially in patients with decreased cognitive functions.

Clinical and radiological 12-year follow-up of full arch maxilla prosthetic restoration supported by dental implants positioned through guide flapless surgery

The computer-guided flapless surgery for implant placement using stereolithographic templates is going to be considered a daily practice technique. The advantages of this kind of surgery are related with its no flap opening, with the precision of the implant positioning and with the possibility of having a quick rehabilitation and low post-surgical discomfort. The introduction of digital planning programs has made it possible to place dental implants in preplanned positions and being immediately functionally loaded by using prefabricated prostheses. This case presented a 12-year follow-up of a maxillary prosthesis supported by dental implant immediately loading and positioned with the first kind of guided flapless surgery technique. Aim of this paper was to report how the guide surgery implant position technique can be considered a predictable and safe technique giving the surgeon excellent long-term results.

Clinical assessment of submerged vs non-submerged implants placed in pristine bone

The medium-long term success of osseointegrated dental implants is evaluated on the basis of the degree of osseointegration over time, assessed by radiographic or instrumental analysis (ISQ). Over the years, the question has always been which surgical technique can provide a better performance in the medium-long term and, thanks to literature studies, it has been evidenced that there are no differences between "one stage" and "two stage" interventions. The purpose of this study is to evaluate clinical and radiographic parameters, referring to interventions for the insertion of dental implants characterized by a new kind of implant surface (Synthegra® GEASS, Udine). The prospective study, not randomized and controlled, referred to the insertion of 18 implants on 9 patients with mono or bilateral edentulism, with measurements at 1, 3, 6 and 12 months and an overall follow-up at 3 years, in order to evaluate the different degree of crestal bone resorption using the submerged and transmucosal surgical technique. The results of our study show that there are no differences in the resorption of the two surgical techniques, with an average bone resorption of 2,05±0,16 mm, comparable with values reported in literature.

Multi-technique study of a ceramic archaeological artifact and its content

In this paper we report the results of a study performed with different physical and chemical methods on a ceramic vase originally attributed to the I century CE. The joint use of infrared spectroscopic analysis and laser techniques, as well as pyrolysis-gas chromatography coupled with mass spectrometry and thermoluminescence, allowed us to characterize the vase material and its content. The chemical data were combined with morphological and stylistic examinations of the object and helped in defining its actual geographical and chronological pertinence.

Separation and determination of denatured caseins by hydrophobic interaction chromatography Part II. Method validation and applications

A method recently described for the separation of denatured alpha-, beta- and kappa-caseins by hydrophobic interaction chromatography was validated by the analysis of reference skim milk powder (BCR-063R) certificated for total nitrogen content. The method is based on fast and easy solubilization of commercial and real samples by 4.0 M guanidine thiocyanate and elution on a TSK-Gel Phenyl-5PW column (TosoHaas) in the presence of 8.0 M urea in the mobile phase. No preliminary precipitation or separation of the casein fraction is required. A linear relationship between the concentration of casein and peak area (UV absorbance detector at 280 nm) was obtained over the concentration range 0.5-60 microM. The detection limits for alpha-, beta- and kappa-caseins ranged between 0.30 and 0.65 microM. The precision of the method was evaluated; the relative standard deviation for alpha-, beta- and kappa-casein determination ranged between 2.2 and 2.7% for standard solutions and between 3.5 and 6.2% for real sample solutions. The mean casein content found in 10 aliquots of BCR-063R calculated with respect to the total protein content (estimated on the basis of certified total nitrogen content) was 79.1+/-2.7%. Results of linear fitting of standard additions data for alpha-, beta- and kappa-caseins to BCR-063R were compared with linear fitting of alpha-, beta- and kappa-casein calibration data. The method was applied to commercial caseins and to 31 real, raw samples [processed cow's milk (pasteurised, UHT-treated), follow-up milk powders, cream, cheeses, casein-free infant formulae, cookies for babies containing milk proteins] with the aim of showing the wide applicability of the method in order to determine alpha-, beta- and kappa-caseins.

Structural dependence of the cellular isoform of prion protein on solvent: spectroscopic characterization of an intermediate conformation

Using circular dichroism, fluorescence, and infrared spectroscopies, we studied the secondary structure of purified hamster PrP(C) in the presence of the mild, nonionic detergent octylglucoside. Under these native conditions, PrP(C) displayed an unexpectedly high beta-sheet component, intermediate between the values previously reported for PrP(Sc) and an isoform of PrP(C) isolated in a zwitterionic detergent. The structure of PrP(C) appeared to depend strongly on the detergent and/or phase. Switching from octylglucoside to zwitterion 3-14 drastically modified PrP secondary structure by increasing the alpha-helix while abolishing the beta-sheet component. In contrast, the conformation of PrP(C) in zwitterion was highly stable, since reverting to octylglucoside did not restore the original native structure. These and other results show that native PrP(C) in octylglucoside has some of the conformational characteristics that make the protein susceptible to conversion into PrP(Sc). Most importantly, this is the first study to demonstrate the intrinsic plasticity of the full-length native PrP(C) isolated from animal brains.

Application of mercury cold vapor atomic fluorescence spectrometry to the characterization of mercury-accessible -SH groups in native proteins

A new analytical approach has been applied to the determination and characterization of mercury-accessible -SH groups in pure native protein samples (ovalbumin, hemoglobin, glyceraldehyde-3-phosphate dehydrogenase, aldolase, pyruvate kinase, hexokinase, lactate dehydrogenase, alcohol dehydrogenase, creatine phosphokinase, lysozyme, and cytochrome c). The method is based on the selective reduction of Hg(II) in the presence of Hg(II)-thiol complexes with alkaline sodium tetrahydroborate, to give Hg(0) in a continuous flow reaction system coupled with atomic fluorescence spectrometric (AFS) detection. The method is fast and specific and allows one to work with nanomole amounts of a single protein without any preliminary incubation and without any separation of Hg(II) from thiol-complexed mercury. The meaning of the results obtained in the determination of the accessible -SH groups in native proteins by using chemical probes is discussed.

Clay-nucleic acid complexes: characteristics and implications for the preservation of genetic material in primeval habitats

The equilibrium adsorption of three nucleic acids: chromosomal DNA, supercoiled plasmid DNA, and 25S rRNA, on the clay minerals, montmorillonite (M) and kaolinite (K), were studied. Adsorption of the nucleic acid on the clays was rapid and maximal after 90 min of contact time. Chromosomal DNA was adsorbed to a greater extent than plasmid DNA and RNA, and the adsorption was also greater on M than on K. Adsorption isotherms were of the L type, and a plateau was reached with all the complexes, with the exception of chromosomal DNA adsorbed on M. To deterine where nucleic acids are adsorbed on clay minerals and the nature of the interaction, complexes were studied by X-ray diffraction (X-RD), electron microscopy, and Fourier transform infrared (FT-IR) spectroscopy. X-RD showed that nucleic acids did not penetrate the clay, indicating that the adsorption occurred primarily on the external surfaces of clay particles, as also suggested by electron microscopy observations. FT-IR spectra of clay-tightly bound nucleic acid complexes showed adsorption bands that indicate a variation of the nucleic acids status as a consequence of their adsorption on clay. Data obtained suggested that the formation of clay-nucleic acid complex could have an important role in the preservation of genetic material in primeval habitats.

Use of CD and FT-IR to determine the secondary structure of purified proteins in the low-microgram range

The spectroscopic characterization of protein secondary structure is often partially unreliable when samples are not extremely pure and abundant. This problem may be overcome by the combination of circular dichroism (CD) and Fourier transform infrared spectroscopy (FT-IR). We used these methods to characterize the secondary structure of two proteins of neurobiological interest, calexcitin (CE) and the cellular isoform of prion protein (PrPC). Both proteins were purified with multiple chromatographic steps and were obtained in buffer with high purity (> 95%) and in low amount (approximately 2 micrograms). The samples were analyzed by circular dichroism (down to 184 or 182 nm), recovered, and deposited on films for infrared analysis. The spectral deconvolution from the two methods yielded secondary structures in good agreement with each other as well as with theoretical predictions based on amino acid sequence. The conformation of CE was found to be dependent on its concentration and on calcium binding. The secondary structure of cellular native PrP varied dramatically with the detergent used. In conclusion, the combination of CD and FT-IR analysis is suitable for the characterization of the conformational changes induced by ligand binding and/or by different solvent conditions when the protein of interest is only scarcely available. The methods used here provide valuable insights into the putative correlation between protein structure and activity.

An approach to the study of primitive thrombocythemia (PT) megakaryocytes by means of Fourier transform infrared microspectroscopy (FT-IR-M)

Chronic myeloid leukemia (CML), polycythemia vera (PV), idiopathic myelofibrosis (IM) and primary thrombocythemia (PT) are myeloproliferative diseases of clonal origin. Megakaryocyte series are commonly involved in these disorders. In a previous paper of us, megakaryocytes (MKs) from PV and PT patients were shown to be more pathological with respect to the MKs from CML. This paper describes a Fourier transform infrared microspectroscopy (FT-IR-M) study analyzing the cytoplasm and nucleus areas of MKs from thrombocythemic patients which exhibited numerous giant cells (from 100 to 190 microm in diameter). The size of these cells makes it possible to analyze the cell parts using FT-IR-M technique. The infrared determinations on 10 single MKs for each case examined in these two different cell regions revealed spectral differences with a high degree of reproducibility. Finally, the spectra of whole MKs from normal donors and from thrombocythemic patients were also compared.

Secondary structure and Ca2+-induced conformational change of calexcitin, a learning-associated protein

Calexcitin/cp20 is a low molecular weight GTP- and Ca2+-binding protein, which is phosphorylated by protein kinase C during associative learning, and reproduces many of the cellular effects of learning, such as the reduction of potassium currents in neurons. Here, the secondary structure of cloned squid calexcitin was determined by circular dichroism in aqueous solution and by Fourier transform infrared spectroscopy both in solution and on dried films. The results obtained with the two techniques are in agreement with each other and coincide with the secondary structure computed from the amino acid sequence. In solution, calexcitin is one-third in alpha-helix and one-fifth in beta-sheet. The conformation of the protein in solid state depends on the concentration of the starting solution, suggesting the occurrence of surface aggregation. The secondary structure also depends on the binding of calcium, which causes an increase in alpha-helix and a decrease in beta-sheet, as estimated by circular dichroism. The conformation of calexcitin is independent of ionic strength, and the calcium-induced structural transition is slightly inhibited by Mg2+ and low pH, while favored by high pH. The switch of calexcitin's secondary structure upon calcium binding, which was confirmed by intrinsic fluorescence spectroscopy and nondenaturing gel electrophoresis, is reversible and occurs in a physiologically meaningful range of Ca2+ concentration. The calcium-bound form is more globular than the apoprotein. Unlike other EF-hand proteins, calexcitin's overall lipophilicity is not affected by calcium binding, as assessed by hydrophobic liquid chromatography. Preliminary results from patch-clamp experiments indicated that calcium is necessary for calexcitin to inhibit potassium channels and thus to increase membrane excitability. Therefore the calcium-dependent conformational equilibrium of calexcitin could serve as a molecular switch for the short term modulation of neuronal activity following associative conditioning.

Qualitative and quantitative analysis of the secondary structure of cytochrome C Langmuir-Blodgett films

A qualitative and quantitative analysis of the conformation of Langmuir-Blodgett (LB) dried films of cytochrome C on silicon wafers was performed by Fourier transform ir (FTIR) spectroscopy. A deconvolution procedure was applied to the amide I band analysis, in order to determine the percentage of the different secondary structures. Qualitative analysis was performed by examining difference spectra. Films obtained by spreading protein solutions at pH 7.4 and 1, dried at 25 and 100 degrees C, on silicon wafers were also examined in order to detect spectral components associated with denatured protein domains, and to compare them with cytochrome C LB films. FTIR spectroscopy showed that the following important changes characterise LB film spectra: (a) the alpha-helix component is higher (its percentage is 57 and 54%) than the one estimated in dried film obtained by spreading the solutions at pH 7.4 on a silicon substrate (43%), (b) there is an increase in the intensity of bands attributed to protonated carboxy group bands, involved and not involved in the formation of hydrogen bonds, and a decrease in those attributed to deprotonated carboxy groups, (c) the intensity of several bands attributed to aromatic amino acids and aliphatic chains increases, and (d) bands due to O-H stretching vibrations of crystallization water are present. These conformational changes could be induced by protein-protein interaction caused by the close packing of molecules that occurs during LB film formation; it cannot be excluded that they may be accompanied by partial changes in the tertiary structure of the protein. A preferential orientation of protein molecules in LB films is also a possibility.

Determination of secondary structure of normal fibrin from human peripheral blood

The secondary structure of human fibrin from normal donors and from bovine and suilline plasma was studied by Fourier transform ir spectroscopy and a quantitative analysis of its secondary structure was suggested. For this purpose, a previously experimented spectrum deconvolution procedure based on the use of the Conjugate Gradient Minimisation Algorithm with the addition of suitable constraints was applied to the analysis of conformation-sensitive amide bands. This procedure was applied to amide I and III analysis of bovine and suilline fibrin, obtained industrially, and to amide III analysis of human fibrin clots. The analysis of both amide I and III in the first case was useful in order to test the reliability of the method. We found bovine, suilline, and human fibrin to contain about 30% alpha-helix (amide I and III components at 1653 cm-1, and 1312 and 1284 cm-1, respectively), 40% beta-sheets (amide I and III components at 1625 and 1231 cm-1, respectively) and 30% turns (amide I and III components at 1696, 1680, 1675 cm-1, and 1249 cm-1, respectively). The precision of the quantitative determination depends on the amount of these structures in the protein. Particularly, the coefficient of variation is < 10% for percentage values of amide I and III components > 15 and 5%, respectively. The good agreement of our quantitative data, obtained separately by amide I and amide III analysis, and consistent with a previous fibrinogen (from commercial sources) study that reports only information about fibrin beta-sheet content obtained by factor analysis, leads us to believe that the amounts of secondary structures found (alpha-helix, beta-sheets, and turns) are accurate.

Determination of the secondary structure of isomeric forms of human serum albumin by a particular frequency deconvolution procedure applied to Fourier transform IR analysis

A new deconvolution procedure was applied to the analysis of Fourier transform ir spectra of human serum albumin secondary structure in the native state and in states denatured by heat and acid treatment. The deconvolution method is based on the use of the Conjugate Gradient Minimization Algorithm, with the addition of suitable constraints directly obtained by the application to the measured spectrum of the second derivative operator. This method computes central band frequency, bandwidth, and amplitude of the different spectral components of conformation-sensitive amide bands. In the specific case, it was applied to analysis of the amide I band, and the quantitative determination of the different secondary structures (alpha-helix, beta-sheet, beta-turns, and random) was attempted for all the samples examined. The precision of the quantitative determination depends on the amounts of these structures present in the protein. The coefficient of variation is < 10% for values of amide I component > 15%. The accuracy was tested by comparing, by means of linear regression, the results obtained for human serum albumin, hemoglobin, alpha-chymotrypsin, and cytochrome c, using our method, with those obtained by x-ray crystallography and CD; the results obtained by other vibrational spectroscopic approaches were also compared. The fit standard error between x-ray and ir secondary structure values estimated by our method is 2.5% for alpha-helix, 7.16% for beta structures, and 5.1% for other structures (turns and random coils). Quantitative results are given for the secondary structures (alpha-helix, turns, and beta-strands) present in the native state (turns and beta-strands up to now unknown in aqueous solution), together with the percentages of these structures and additional ones (random coils and beta-sheets) formed during denaturization.

Recombinant alpha 2a interferon and polycythemia vera: clinical results and biological evaluation by means of Fourier-transform infrared microspectroscopy

Polycythemia vera (PV) is a chronic myeloproliferative disease. The use of recombinant alpha 2a Interferon (IFN) therapy in this disease is a novel approach. We applied Fourier-transform infrared microspectroscopy (FT-IR-M) to investigate the behavior and therapeutic responsiveness of PV patients treated with IFN. A spectroscopic parameter (A1/A2) was used, corresponding to the ratio of the integrated areas of the bands at 1080 cm-1 and at 1540 cm-1 due to nucleic acids and proteic components, respectively, calculated on the spectra of single megakaryocytes (MKs). In previous studies, we have pointed out that MKs in PV have a surprisingly strong myeloproliferative impulse when compared to MKs from other chronic myeloproliferative diseases. Nine patients out of the 11 studied exhibited a satisfactory responsiveness to the IFN treatment. Ten patients were evaluated by the A1/A2 parameter. In 8 of these, a good agreement was seen between this parameter and the laboratory data commonly used for the assessment of this disease. The infrared parameter, which we propose, proves to be an original, reliable method for the evaluation of recombinant alpha 2a IFN responsiveness in this disease.