The effect of acid treatment on the structure and surface acidity of tetraalkylammonium-montmorillonites.

The effect of tetrabutylammonium (Bu4N+) and tetrapentylammonium (Pe4N+) cations on the modification of the organo-montmorillonite structure upon acid-treatment was investigated. Samples were treated with HCl for various times (2-12 h). Structural changes were followed by MAS NMR spectroscopy. The 29Si MAS NMR spectra of initial Na-saturated form (Na-SAz) showed gradual decrease of the intensity of the resonance assigned to SiO4 cross-linked in the tetrahedral sheets Q3(0Al) while signals arising from the reaction product Q31OH and Q4(0Al) became more pronounced upon acid treatment. The Q3(0Al) signal almost completely disappeared for Na-SAz treated for 8 h on contrary to Bu4N-SAz and Pe4N-SAz showing signal of relatively high intensity even after 12 h. The 27Al MAS NMR measurement proved that more than one half of Al remained in the reaction product of Bu4N-SAz and Pe4N-SAz after 8 h treatment, while Al content dropped below 5% for Na-SAz. Formation of acid sites was investigated via pyridine adsorption. Only physically adsorbed and H-bonded pyridine was detected for acid-untreated samples. In contrast, the IR spectra of the samples partially decomposed in HCl revealed bands of pyridine adsorbed on Brønsted acid sites. Strongly bonded pyridine was able to bear up heating even at 230°C.

A rare case of isolated kidney cysticercosis.

A rare case of isolated kidney cysticercosis is presented. Clinical signs and diagnostic findings are unspecific. They are discussed and a conservative therapeutic approach is suggested.

Ki-67 expression in oral lichen planus.

PURPOSE: The monoclonal antibody Ki-67 detects a nuclear antigen that is present only in proliferating cells. This is of particular interest for the analysis of the proliferation rates of malignant tumors. The aim of this study was to investigate the malignant potential of oral lichen planus (OLP) on the basis of expression of Ki-67 in healthy individuals (HI), patients with OLP and patients with squamous cell carcinoma (SCC), and to see for any potential interdependence between Ki-67 expression and different clinical and histopathological parameters in OLP. METHODS: Immunohistochemistry for Ki-67 was carried out using an avidin-biotin peroxidase complex method. RESULTS: Ki-67 was more expressed in keratinocytes and lymphocytes of OLP patients compared with HI, but less compared with patients with SCC. Keratinocytes and lymphocytes stained with Ki-67 in OLP patients were significantly higher in males, and in OLP specimens showed less developed civatte bodies (CB) and thickening of the basal membrane (TBM). CONCLUSION: Ki-67 may not serve as prognostic biomarker in oral cancer development from the initially diagnosed OLP, but it could help selecting patients with higher need of follow up for prevention of malignancy.

Alterations of the surface and morphology of tetraalkyl-ammonium modified montmorillonites upon acid treatment.

The effect of short alkyl chain cations on the modification of the structure, surface and textural properties of organo-montmorillonites upon their acid treatment was investigated. Samples prepared from Ca-SAz montmorillonite and tetramethylammonium (Me(4)N(+)-), tetraethylammonium (Et(4)N(+)-), tetrapropylammonium (Pr(4)N(+)-) and tetrabutylammonium (Bu(4)N(+)-) salts were treated in 6 M HCl at 80 °C for 2-8 h and analyzed by different methods. Acid treatment of organo-montmorillonites caused gradual release of Al and Mg from the octahedral sheets and destruction of their layered structure. The extent of the changes depended significantly on the size of organo-cation. While large plate-like particles of Ca-SAz and Me(4)N-SAz were disintegrated during acid treatment and smaller fine grains were created, the morphology of Bu(4)N-SAz was modified only slightly. Pore size analysis showed generation of pore network upon organo-montmorillonites dissolution. After longer acid attack, pore volume increased and pore size distribution curves were shifted to pores with diameter above 25 Å. The surface area of acid-treated samples increased due to destruction of the montmorillonite layers and formation of the SiO(2)-rich reaction product. The highest value 475 m(2)/g was observed for Me(4)N-SAz treated 4 h. Surface area of Et(4)N-SAz, Pr(4)-SAz and Bu(4)N-SAz was 441, 419 and 293 m(2)/g, respectively, after 8 h treatment. Similar decomposition level was observed for Ca-SAz and Me(4)N-SAz, and less destruction was found for Et(4)N-SAz, Pr(4)-SAz and very low for Bu(4)N-SAz. Though Bu(4)N(+) is short alkyl chain cation, its size is large enough to cover the inner and outer surfaces of montmorillonite and thus to protect the clay layers from acid attack.

Spectral properties of rhodamine 6G in smectite dispersions: effect of the monovalent cations.

Montmorillonite monoionic forms with alkali metal and NH(4)(+)-cations were prepared by ion exchange. The hydration properties and binding of the ions to montmorillonite surface and the swelling properties of the mineral specimens were analyzed. Whereas Na(+)- and Li(+)-ions were fully hydrated over a large range of conditions, large size K(+), NH(4)(+), and mainly Rb(+) and Cs(+) ions were apt to bind directly to the oxygen atoms on the mineral surface. The forms with large ions exhibited reduced hydration and swelling and the absence of macroscopic swelling of the respective aqueous colloids. The interaction of laser dye rhodamine 6G (R6G) in montmorillonite colloids was investigated by absorption and steady-state fluorescence spectroscopies. Significant effects of the properties of both the inorganic ions and swelling properties of colloidal dispersions on R6G molecular aggregation were observed. Large amounts of the molecular aggregates were formed in the colloids of Na(+)- and Li(+)-montmorillonites. The aggregates absorbed light at significantly lower wavelengths (~460 nm) with respect to the light absorption by monomers (535 nm). Fluorescence spectroscopy provided a key evidence for the assignment of the type of the aggregates: The emission of the aggregates at relatively low energies proved these assemblies are rather a mixed H-/J-type than ideal H-aggregates. The presence of parent inorganic cations of larger size led to a significant lowering of the amount of the R6G aggregates in favor of the monomers. Investigations of the evolution of the dye aggregation with time indicated basic features of dye aggregation reaction: The size of parent inorganic ions did not affect the reaction mechanism, but rather limited the extent of the reaction. Probably the forms with large inorganic ions, such as Rb(+) and Cs(+), did not provide sufficient surface for the formation of the large size assemblies of the dye. This property can be explained in terms of strong association of the large alkali metal ions to clay mineral surface, as well as to reduced swelling in the colloidal systems of respective forms.

Oral status in patients receiving 5-fluorouracil for colorectal cancer.

PURPOSE: Oral complications are frequent and troublesome symptoms for those undergoing chemotherapy for cancer. Several antineoplastic agents are proved to have stomatotoxic potential, among them 5-fluorouracil (5-FU). The aim of the present study was to evaluate the oral status and patient experiences during chemotherapy with 5-FU for colorectal cancer. METHODS: Twenty-eight patients treated with 5-day 5-FU plus leucovorin entered this study. Positive data about oral symptoms were taken by anamnesis. Mucositis severity index, gingival index, plaque index, probing pocket depth and bleeding on probing have been used to assess oral mucosa and periodontal status of the patients. Patients were examined prior to chemotherapy and 14 days after the start of the chemotherapy cycle. RESULTS: Mild to moderate subjective complaints concerning oral cavity were reported by 17.9% of patients before and 39.2% of patients after chemotherapy. Clinical examination revealed oral mucosa damage in 10.7% and 35.7% of patients, with mean mucositis score of 0.14 and 0.54 before and after chemotherapy, respectively. Although mean values of all periodontal indices were elevated after chemotherapy, only increase in gingival index was statistically significant (p=0.035). Mucositis was significantly correlated with oral pain (p=0.00), xerostomia (p=0.00), and plaque index (p=0.077), while the correlation between mucositis and the rest of the examined parameters was not significant. CONCLUSION: Oral complications were not highly expressed in this study. Although 5-FU is considered to exert significant stomatotoxic effect, severe mucositis was far less common in this study compared to studies reported elsewhere.

Bcl-2 expression and its possible influence on malignant transformation of oral lichen planus.

PURPOSE: The aim of this study was to investigate the malignant potential of oral lichen planus (OLP) on the basis of the expression of the Bcl-2 marker in healthy individuals (H), patients with OLP and patients with squamous cell carcinoma (SCC), and to establish potential interdependence between expression of Bcl-2 and the different clinical and histopathological parameters in H, OLP, and SCC. METHODS: Immunohistochemistry for Bcl-2 was carried out using an avidin-biotin peroxidase complex method. Tissue sections were treated with mouse monoclonal antibody against Bcl-2 (124, DAKO A/S, Denmark; dilution 1/100). Immunohistochemical parameters measured included total tissue area, total stained area and intensity of stain. RESULTS: Keratinocytes were not Bcl-2 positive in H and were sparsely positive in OLP. The number of lymphocytes stained with Bcl-2 was significantly lower in H as compared to patients with SCC and OLP. Bcl-2 staining was weak to moderate in OLP, and moderate to intense in SCC. Bcl-2-positive lymphocytes were more expressed in older OLP patients (>55 years), and in OLP specimens with orthokeratinized epithelium, less developed acanthosis and highest grade of lymphocyte expression. CONCLUSION: Bcl-2 may not serve as a prognostic biomarker in oral cancer development from OLP, but it could help in selecting patients with higher need of follow up to prevent malignancy.

A systematic review of salivary gland hypofunction and xerostomia induced by cancer therapies: prevalence, severity and impact on quality of life.

PURPOSE: This systematic review aimed to assess the literature for prevalence, severity, and impact on quality of life of salivary gland hypofunction and xerostomia induced by cancer therapies. METHODS: The electronic databases of MEDLINE/PubMed and EMBASE were searched for articles published in English since the 1989 NIH Development Consensus Conference on the Oral Complications of Cancer Therapies until 2008 inclusive. Two independent reviewers extracted information regarding study design, study population, interventions, outcome measures, results and conclusions for each article. RESULTS: The inclusion criteria were met by 184 articles covering salivary gland hypofunction and xerostomia induced by conventional, 3D conformal radiotherapy or intensity-modulated radiotherapy in head and neck cancer patients, cancer chemotherapy, total body irradiation/hematopoietic stem cell transplantation, radioactive iodine treatment, and immunotherapy. CONCLUSIONS: Salivary gland hypofunction and xerostomia are induced by radiotherapy in the head and neck region depending on the cumulative radiation dose to the gland tissue. Treatment focus should be on optimized/new approaches to further reduce the dose to the parotids, and particularly submandibular and minor salivary glands, as these glands are major contributors to moistening of oral tissues. Other cancer treatments also induce salivary gland hypofunction, although to a lesser severity, and in the case of chemotherapy and immunotherapy, the adverse effect is temporary. Fields of sparse literature included pediatric cancer populations, cancer chemotherapy, radioactive iodine treatment, total body irradiation/hematopoietic stem cell transplantation, and immunotherapy.

A systematic review of salivary gland hypofunction and xerostomia induced by cancer therapies: management strategies and economic impact.

PURPOSE: This systematic review aimed to assess the literature for management strategies and economic impact of salivary gland hypofunction and xerostomia induced by cancer therapies and to determine the quality of evidence-based management recommendations. METHODS: The electronic databases of MEDLINE/PubMed and EMBASE were searched for articles published in English since the 1989 NIH Development Consensus Conference on the Oral Complications of Cancer Therapies until 2008 inclusive. For each article, two independent reviewers extracted information regarding study design, study population, interventions, outcome measures, results, and conclusions. RESULTS: Seventy-two interventional studies met the inclusion criteria. In addition, 49 intensity-modulated radiation therapy (IMRT) studies were included as a management strategy aiming for less salivary gland damage. Management guideline recommendations were drawn up for IMRT, amifostine, muscarinic agonist stimulation, oral mucosal lubricants, acupuncture, and submandibular gland transfer. CONCLUSIONS: There is evidence that salivary gland hypofunction and xerostomia induced by cancer therapies can be prevented or symptoms be minimized to some degree, depending on the type of cancer treatment. Management guideline recommendations are provided for IMRT, amifostine, muscarinic agonist stimulation, oral mucosal lubricants, acupuncture, and submandibular gland transfer. Fields of sparse literature identified included effects of gustatory and masticatory stimulation, specific oral mucosal lubricant formulas, submandibular gland transfer, acupuncture, hyperbaric oxygen treatment, management strategies in pediatric cancer populations, and the economic consequences of salivary gland hypofunction and xerostomia.

Expression of Fas/FasL in patients with oral lichen planus.

PURPOSE: To investigate the malignant potential of oral lichen planus (OLP) on the basis of expression of the Fas/FasL markers in healthy individuals (H), OLP patients and patients with squamous cell carcinoma (SCC). PATIENTS AND METHODS: 40 patients with OLP and two control groups were included in this research (H and patients with SCC). Immunohistochemistry for Fas and FasL was carried out using an avidin-biotin peroxidase complex method. RESULTS: Only a low percentage of infiltrating lymphocytes and no keratinocytes were Fas-positive in OLP specimens. The highest percentage of Fas-staining keratinocytes in our survey was identified mostly in H and patients with well-differentiated SCC. In most cases of SCC, OLP and H a high percentage of keratinocytes and lymphocytes were FasL-positive. FasL expression was negatively correlated with the degree of cell differentiation and apoptosis. Taking into consideration that all carcinomas in this survey were highly differentiated, it is not surprising that no statistically significant differences in FasL expression between H, OLP and SCC specimens were detected. CONCLUSION: Downregulation of Fas expression in keratinocytes and lymphocytes of OLP specimens, together with upregulation of FasL, may serve as initial prognostic biomarker in oral cancer development.

Humoral immunity to cow's milk proteins and gliadin within the etiology of recurrent aphthous ulcers?

OBJECTIVES: The goal of this study was to determine the incidence of serum antibodies to gliadin and to cow's milk proteins (CMP) using ELISA test, within patients who have recurrent aphthous ulcers (RAU). SUBJECTS AND METHODS: Fifty patients with recurrent aphthous ulcers and fifty healthy people were included in this research. Levels of serum IgA and IgG antibodies to gliadin and IgA, IgG and IgE to CMP were determined using ELISA. RESULTS: The levels of serum antigliadin IgA and IgG antibodies were not significantly higher in patients with RAU in comparison with the controls (P = 0.937 and P = 0.1854 respectively). The levels of serum anti-CMP IgA, IgG and IgE antibodies were significantly higher in patients with RAU in comparison with the controls (P < 0.005, P < 0.002 and P < 0.001 respectively). In general, the increased humoral (IgA or IgG) immunoreactivity to CMP was found in 32 of 50 patients, while 17 of them showed the increased levels of both IgA and IgG immunoreactivity to CMP. At the same time, 16 out of 50 patients had IgA, IgG and IgE immunoreactivity to CMP. CONCLUSION: These results indicate the strong association between high levels of serum anti-CMP IgA, IgG and IgE antibodies and clinical manifestations of recurrent aphthous ulcers.

High-dose calcitriol therapy and progression of cardiac vascular calcifications.

BACKGROUND: Dialysis patients show a very high prevalence of cardiovascular complications, affected as they are with abnormal and accelerated vascular calcifications and, eventually, calcium and phosphorous metabolism disorders. Multislice computed tomography (MSCT) provides a reproducible, high-resolution imaging of calcium contained in cardiac arteries, measured by Agatston score. The aim of the present study was to evaluate the influence of high-dose and low-dose calcitriol therapy on the progression of cardiac vascular calcifications in dialyzed patients. METHODS: We enrolled 36 dialyzed patients in a prospective study, including an interventional period of 12 months and a follow-up period of 12 months. Eighteen protocol patients received intravenous pulses of high-doses calcitriol at the end of dialytic treatment and sevelamer hydrochloride therapy. Control patients received low-dose calcitriol and sevelamer hydrochloride as well. Two MSCT scans were performed: 1 at the start of the study and 1 at the end of follow-up, and Agatston score was calculated at both examinations. RESULTS: At first examination, protocol patients showed almost the same level of cardiac vascular calcification as control patients. At the second MSCT, statistically significantly higher values of Agatston score were recorded for all patients. Indeed, patients who showed higher baseline values developed worse calcifications as recorded at the end of follow-up, both in the protocol and control group. CONCLUSIONS: Our data show that baseline level is strongly predictive of vascular calcification progression, and, moreover, there is no association between calcitriol administered doses and the progression of cardiac vascular calcification.

Presence of herpes simplex virus on the oral mucosa in patients undergoing chemotherapy.

BACKGROUND: The aim of this study was to confirm the presence of herpes simplex virus type 1 and 2 on the oral mucosa, in patients undergoing chemotherapy, by means of polymerase chain reaction (PCR). METHODS: The research was carried out on 40 patients receiving chemotherapy as treatment for different malignancies. The status of oral mucosa and viral presence were assessed in all patients at the initial examination (prior to chemotherapy), and at the control examination (two weeks after the initiation of the chemotherapeutic cycle). RESULTS: The presence of HSV-1 was detected in 28 patients (70%) prior to chemotherapy, of whom 7 (25%) manifested oral complications. The control examination showed the presence of HSV-1 in 35 patients (87.5%), of whom 23 (65.7%) presented oral mucosa changes. HSV-2 has not been detected in any of the patients.

Cardiac calcifications in hemodialysis patients assessed with spiral computed tomography.

AIM: Cardiac disease is a major cause of mortality in uremic patients. The aim of this paper was to evaluate cardiac calcium content in uremic patients with multislice computed tomography (MSCT). METHODS: The study has been carried out on 120 uremic and 28 nonuremic patients affected by cardiovascular disease. Serum calcium, phosphorus, calcium-phosphate product, intact PTH were assayed. Several lipidic and nutritional parameters were measured. Calcification values obtained with the MSCT were reported in terms of Agatson scores. RESULTS: We found that the average score values in cohort on uremic was 10 times higher than in nonuremic patients (score values 3.389 vs 328). Cardiac calcification score was found to be correlated significantly to age (P=0.006), HD age (P=0.010), serum calcium (P=0.006), iPTH (P=0.004). Multiregression analysis (MRA) with the cardiac score as dependent variable selected the following variables (R(2) 0.612): age (P=0.002), HD age (P=0.010), serum cholesterol (P<0.000), triglycerides (P=0.001) and inversely HDL cholesterol (P=0.001) and non-HDL cholesterol (P=0.001) as predictive variables for cardiac score. By comparing patients with scores lower and higher than 400, the group with score <400 showed a significantly lower age (P=0.0001), HD vintage (P=0.01) and a significantly higher serum cholesterol (P=0.009), HDL cholesterol (P=0.05) and non-HDL cholesterol (P=0.05). CONCLUSIONS: The MSCT could help in identifying and stratifying high-risk patients to implement preventive strategies. The control of mineral metabolism and of lipid levels is important in prevention of arterial calcification in uremic patients.

All-optical switching and multifrequency generation in a dual-core photonic crystal fiber.

We demonstrate all-optical switching at 1550 nm between two weakly coupled cores in a photonic crystal fiber for intensities up to 0.5 TW/cm2. Spectrum analysis at higher intensities reveals that the output was dominated by continuum generation primarily towards shorter wavelengths.

Cardiac calcium evaluation in hemodialysis patients with multisection spiral computed tomography.

AIM: The aim of this study is cardiac calcium content evaluation in hemodialysis patients by a new technique, based on ultrafast multisection CT (MTC). METHODS: The study was carried out on 30 HD patients, 14 F and 16 M, average age 57.7 +/- 13.9 years, average HD age 57.3 +/- 47.4 months. The intact PTH levels were 625.4 +/- 571 pg/mL. Serum calcium, phosphate and CaxP product were 9.75 +/- 0.84 mg/mL, 6.21 +/- 1.01 mg/dL and 60.2 +/- 10.7 mg2/dL2, respectively. RESULTS: The values obtained with the MTC technique were reported in terms of Agatson scores. Score values frankly in the pathologic range (>100) were found in 24 patients (80%). Correlation analysis has shown positive and significant correlation coefficients of the score with patients' age (p = 0.003), serum calcium (p = 0.012), CaxP (p = 0.015), iPTH (p = 0.049), and borderline, to HD age (p = 0. 06). CONCLUSION: Risk factors for cardiac calcification are mainly age, degree of hyperparathyroidism, increased CaxP and serum calcium levels. A control of calcium phosphate parameters in hemodialysis patients seems to be mandatory to avoid increased severity of coronary artery disease.

Spatial modulation instability in a Kerr slab waveguide.

We report the observation of noise-initiated modulational instability in AlGaAs slab waveguides at 1.55 microm . Experiments were performed with the local, ultrafast Kerr nonlinearity at half the bandgap. The agreement between experiment and theory for the periodicity versus intensity was good.

[The epithelium of the periodontal pocket--an electron microscopy analysis]. / Epitel parodontalnog dzepa--analiza elektronskim mikroskopom.

The aim of this study was to examine intra- and intercellular changes that characterize the periodontal pocket epithelian. Biopsy specimens of human gingiva were prepared for an electron microscope study by a routine histological procedure. Results of the histological preparations analyses revealed changes significant for pathogenesis of gingivitis and periodontal disease because they cause destruction of epithelial barrier. Such a damaged periodontal pocket epithelium enables further invasion of harmful noxae and spreading of destructive processes into deeper parts of the periodontium.

Salivary immunoglobulins in cancer patients with chemotherapy-related oral mucosa damage.

In 40 patients with neoplastic disorders treated with chemotherapy containing anthracyclines or 5-fluorouracil, objective changes of the oral mucosa were registered in 22 patients (55%). Serum IgG and IgA levels and the mean serum IgG/IgA ratio were normal. On the contrary, the mean IgG/IgA salivary ratio was 1.27 (normally below 1.0) due to an increased salivary concentration of IgG (mean 0.095 g/l), but also due to a decreased IgA concentration (mean 0.075 g/l); the IgG/IgA ratio in saliva was higher in patients with objective changes of the oral mucosa (1.53). Values of the periodontal indices were compatible with the diagnosis of a manifest periodontal disease, which tended to be more severe than in control groups. A positive correlation between the gingival index and concentration of IgG in saliva, a non-linear correlation between the gingival index and salivary IgA and a positive linear correlation between serum IgA concentration and intensity of periodontal attachment level recession, indicate local and systemic immune responses to periodontal tissue alterations and dental plaque components. The IgA related local humoral immune response is, however, operating at a lower concentration level than in healthy individuals.