Uros Skaleric

Proviral HIV-1 DNA in Gingival Crevicular Fluid of HIV-1-infected Patients in Various Stages of HIV Disease

The oral cavity is rarely reported to be a site of human immunodeficiency virus (HIV) transmission, despite detectable virus in saliva and relatively frequent prevalence of periodontal disease in HIV-infected persons yielding increased excretion of mononuclear-cell-enriched gingival fluid. To search for possible sources of HIV in saliva, and using the polymerase chain-reaction technique, we sought the presence and shedding patterns of proviral HIV-1 DNA in gingival crevicular fluid in a group of patients previously determined as HIV-1-seropositive. Periodontal status at the collection sites was monitored by several clinical parameters, including Plaque Index, Gingival Index, probing depth, and clinical attachment loss. Gingival crevicular fluid samples were collected by means of paper points. Proviral HIV-1 DNA was detected in the gingival fluid of 17 out of 35 HIV-1-infected patients. Its detection correlated significantly with higher plasma HIV-1 RNA viral load (p = 0.03) and not with peripheral blood CD4+ cell count, the presence of blood in gingival fluid, or oral lesions. There was a significant correlation between clinical attachment loss at the sites of fluid collection and plasma HIV-1 RNA viral load (p = 0.002), and borderline correlation between the latter and probing depth (p = 0.54) in the group of patients harboring proviral HIV-1 DNA in gingival crevicular fluid. The results of our study suggest that mononuclear cells present in gingival crevicular fluid and harboring proviral HIV-1 DNA could represent a potential source of HIV-1 in the presence or absence of local bleeding, especially in persons with advanced HIV infection and increased loss of clinical attachment.

Immunolocalization of Inducible Nitric Oxide Synthase in Localized Juvenile Periodontitis Patients

Localized juvenile periodontitis (LJP) is associated with a destruction of periodontal tissues and the presence of Actinobacillus actinomycetemcomitans ( AA ). Lipopolysaccharide (LPS) from AA was found to induce a significant macrophage production of nitric oxide (NO). Increased nitric oxide synthase (NOS) activity was found to be negatively correlated with the neutrophil chemotactic response. The aim of this study was to determine the occurrence and distribution of inducible NOS (iNOS) in human gingival tissue from LJP patients. The distribution of iNOS was assessed by monoclonal antibody against iNOS. Cellular markers (CD 3, CD 20, and CD 68) were used to determine the cellular origin of iNOS. The immunostaining revealed the appearance of iNOS in inflamed compared to noninflamed gingival tissues. Macrophages expressed high levels of iNOS that may cause some damage to the periodontal tissues. This study suggests that iNOS activity in macrophages may modify abnormalities of neutrophil function.

The impact of image information on compressibility and degradation in medical image compression

The aim of the study was to demonstrate and critically discuss the influence of image information on compressibility and image degradation. The influence of image information on image compression was demonstrated on the axial computed tomography images of a head. The standard Joint Photographic Expert Group (JPEG) and JPEG 2000 compression methods were used in compression ratio (CR) and in quality factor (QF) compression modes. Image information was estimated by calculating image entropy, while the effects of image compression were evaluated quantitatively, by file size reduction and by local and global mean square error (MSE), and qualitatively, by visual perception of distortion in high and low contrast test patterns. In QF compression mode, a strong correlation between image entropy and file size was found for JPEG (r=0.87, p < 0.001) and JPEG 2000 (r=0.84, p < 0.001), while corresponding local MSE was constant (4.54) or nearly constant (2.36-2.37), respectively. For JPEG 2000 CR compression mode, CR was nearly constant (1:25), while local MSE varied considerably (2.26 and 10.09). The obtained qualitative and quantitative results clearly demonstrate that image degradation highly depends on image information, which indicates that the degree of image degradation cannot be guaranteed in CR but only in QF compression mode. CR is therefore not a measure of choice for expressing the degree of image degradation in medical image compression. Moreover, even when using QF compression modes, objective evaluation, and comparison of the compression methods within and between studies is often not possible due to the lack of standardization of compression quality scales.

Proinflammatory and antimicrobial nitric oxide in gingival fluid of diabetic patients with periodontal disease

ABSTRACT Abnormal nitric oxide (NO) synthesis has been implicated in the pathogenesis of both periodontal disease and diabetes mellitus. In diabetic patients, increased inducible NO synthase in inflamed gingiva correlated with NO in gingival crevicular fluid. Although increased NO reflected more-severe inflammation, it was associated with reductions in CFU of Prevotella intermedia, a major periodontopathogen, highlighting dual roles for NO.

Immunochemical quantitation of cysteine proteinase inhibitor cystatin C in inflamed human gingiva.

The amount of the low molecular-weight inhibitor, cystatin C, was determined by the enzyme-linked immunosorbent assay. Gingival tissue samples were obtained during periodontal surgery from 22 patients with different degrees of inflammatory periodontal disease, as indicated by gingival index and probing depth (PD). The concentration of cystatin C was in the range from 0.21 to 3.82 micrograms/g tissue and was significantly decreased (p less than 0.01) in samples taken from sites with increased PD.

EPR study of mucoadhesive ointments for delivery of liposomes into the oral mucosa

Local drug delivery to the oral cavity tissues has been used for treatment of periodontal disease, aphthosus stomatitis, lichen planus, bacterial and fungal infections. The liposome stability in different mucoadhesive ointments, their transport into dogs oral mucosa and gingiva and washing out of ointments from tissue surface was investigated by electron paramagnetic resonance (EPR). Liposomes were composed of soya lecithin, cholesterol and lipoaminosalt (55:35:10 w/w) and encapsulated with spin labeled water soluble spin probe ASL (N-1-oxyl-2,2,6,6-tetramethyl-4-piperidinyl-N-dimethyl-N-hydroxyethylammonium iodide). Polymethyl methacrylate, Carbopol 934P and Orabase as the bioadhesive ointments were used. The stability of liposomes did not change significantly after mixing with polymethyl methacrylate, but decreases in Carbopol and even more in Orabase. Washing out experiment shows that all three ointments adhere well to oral mucosa and gingiva. After 10 min of washing, approximately 30% of hydrogels were washed out. The transport experiment showed that liposomes limit the transport of hydrophilic substance to the superficial layer of epithelium. In oral mucosa, as opposed to gingiva, hydrogels enhance the transport as compared to solution of ASL or liposomes. Among the examined ointments, polymethyl methacrylate proved to be the most appropriate for local application of liposome entrapped drug to oral mucosa or gingiva.

Study of the Arrangement of Crystallites in y-Irradiated Human Enamel by Electron Paramagnetic Resonance

The arrangement of tooth enamel microcrystals has been studied on CO3 3- bound electrons by electron paramagnetic resonance. It was found that noncarious human maxillary central incisors have a greater degree of alignment of tooth enamel microcrystals than the carious ones. The outermost surface layer of enamel showed a greater crystallite degree of alignment than other parts.

Mirocrystal Arrangement in Human Deciduous Dental Enamel Studied by Electron Paramagnetic Resonance

The arrangement of microcrystallites in human deciduous enamel was studied by electron paramagnetic resonance using a stable CO33––radiation centre as a probe. Enamel

Effects of pulsed CO2 and Er:YAG lasers on enamel and dentin

Enamel and dentin samples were exposed extraorally to pulsed TEA CO2 lasers with pulse durations of 1 microsecond(s) ec and 0.1 microsecond(s) ec. The ablation rate is for energy densities above 5 J/cm2 independent of the CO2 laser energy. For 1 microsecond(s) long CO2 pulses the ablation rate is 3 micrometers /pulse for drilling in enamel, and 8 micrometers /pulse for drilling in dentin. Drilling with 0.1 microsecond(s) CO2 laser results in lower ablation rates of approximately 1 micrometers /pulse in enamel, and 4 micrometers /pulse in dentin. At all experimental energy densities plasma formation is observed, effectively reducing the amount of energy deposition. Compared with these results, experiments with the Er:YAG laser show that 200 microsecond(s) long Er:YAG laser pulses achieve better ablation in the high energy density range because ablation is not diminished as rapidly by the plasma formation. The Er:YAG laser saturated ablation rates are approximately 60 micrometers /pulse for drilling in dentin and 40 micrometers /pulse for drilling in enamel.

Anti-NGF Treatment Reduces Bone Resorption in Periodontitis

Periodontitis is characterized by periodontal tissue destruction, including the alveolar bone. One of its critical components is the release of pro-inflammatory neuropeptides from sensory nerve endings innervating the periodontium. Since nerve growth factor (NGF) has been reported to up-regulate neuropeptides in sensory neurons, we hypothesized that it would be increased in ligature-induced periodontitis in rats, and that systemic NGF neutralization would reduce the periodontitis-associated alveolar bone resorption. Real-time PCR analysis disclosed a statistically significant time-dependent up-regulation of NGF mRNA in gingiva during 2 weeks of periodontitis. Interestingly, NGF up-regulation was also detected in the contralateral gingiva. In addition, immunohistochemistry of trigeminal ganglion neurons innervating the gingivomucosa demonstrated increased expression of TrkA receptor for NGF. Systemic anti-NGF treatment during periodontitis significantly reduced interleukin-1β expression in gingiva and bilateral alveolar bone resorption. This suggests that NGF promotes periodontal inflammation and implicates a possible use of anti-NGF treatment in periodontitis.