BONE CEMENT AND GENTAMICIN IN THE TREATMENT OF BONE INFECTION. BACKGROUND AND IN VITRO STUDY

Objective: To determine the elution characteristics of the antibiotic (gentamicin) mixed with bone cement. Methods: 480mg of gentamicin was added to 40g of bone cement. Ten specimens were immersed in buffered saline solution for 28 days. Samples of days 1, 2, 7, 14, 21 and 28 were analyzed by the fluorescence polarization immunoassay method, Results: Most of the gentamicin was eluted from the cement in the first 24 hours. A gradual downslide occurred between days 2 and 14. By the 28th day, there was no trace of the antibiotic. Conclusion: The mixture released high amounts of the antibiotic in a predictable (therapeutic) manner during at least fourteen days.

Human leukocyte antigen (HLA) and single nucleotide polymorphisms (SNPs) tumor necrosis factor (TNF)-alpha-238 and-308 as genetic markers of susceptibility to psoriasis and severity of the disease in a long-term follow-up Brazilian study

Background The strongest genetic marker for psoriasis is Cw*06. Polymorphisms in the tumor necrosis factor (TNF)-alpha promoter region, especially replacement of guanine with adenine in positions -238 and -308 are related to higher TNF-alpha production and higher risk for psoriasis in Caucasoid populations, not found in Asians. We performed a case-control study of 69 patients with psoriasis type I and 70 controls, characterized clinical progression along 10-years of follow-up in mild or severe disease and determined HLA class I, II, and TNF single nucleotide polymorphisms (SNPs) -238 and -308 polymorphisms to demonstrate whether these polymorphisms may be genetic risk for susceptibility to psoriasis or severity of the disease in Brazilians. Methods Polymorphisms were identified using PCR/SSP. Alleles, genotypes, and haplotypes frequencies were compared using Fisher`s test. Results More severe disease was found in male patients. It may be suggested that alleles B*37, Cw*06, Cw*12, and DRB1*07 were associated with severe disease course, while B*57 with mild disease. No statistical difference was found between the patients and controls regarding polymorphisms frequencies in TNF SNPs. This study pointed to a higher TNF-238 G/G genotype frequency (OR: 3.21; CI: 1.06-9.71; P = 0.04) in the group with severe disease. Conclusions Polymorphisms in the TNF-alpha SNPs do not seem to be a more important genetic risk factor for psoriasis than the already known Cw*06 in Brazilian patients, but these markers may be related to clinical manifestations.

Roux-en-Y Bypass Gastroplasty: Markers of Oxidative Stress 6 Months After Surgery

This study examined the effect of weight loss on energy intake, vitamin C, E, beta-carotene (diet/blood), reduced glutathione (GSH), C-reactive protein (CRP), thiobarbituric acid reactive substances (TBARS), catalase, and myeloperoxidase, in patients with Roux-en-Y bypass gastroplasty. Prospective clinical study with control (C) and bariatric (B) groups (n = 20 each). Age was 38.8 +/- 11.1 (C) and 37.8 +/- 11.2 years (B), and body mass indices (BMI) were 22.4 +/- 2.4 and 48.1 +/- 8.7 kg/m(2), respectively. Group C was assessed on a single occasion and B at three time points (basal period and 3 and 6 months after gastroplasty). BMI was decreased at three (38.3 +/- 1.7, P = 0.018) and 6 months after surgery (34.9 +/- 1.7, P < 0.001). Mean weight loss was 20.53 +/- 1.1 after three and 27.96 +/- 1.3 kg after 6 months. Serum vitamin C and beta-carotene (P < 0.01 and P < 0.001, respectively) were increased at 6 months compared to basal. Basal serum vitamin C (P = 0.001) and beta-carotene (P < 0.001) were lower compared to controls. Serum vitamin E corrected for cholesterol and triglycerides was higher in group B at three (P = 0.01) and 6 months (P = 0.001) and lower at basal (P < 0.001) compared to controls. GSH was higher in controls (P < 0.001) compared to basal. Catalase (P = 0.01) and TBARS (P < 0.001) were higher in group B at 6 months. TBARS were higher (P < 0.001) at basal compared to controls. Myeloperoxidase and CRP decreased in group B after three (P = 0.028, P = 0.010) and 6 months (P < 0.001, P = 0.001), respectively. Roux-en-Y bypass gastroplasty led to decreased proinflammatory parameters together with increased nutritional antioxidants, catalase, and TBARS, and decreased GSH 6 months after surgery.

Enhanced concentrations of relevant markers of nitric oxide formation after exercise training in patients with metabolic syndrome

Metabolic syndrome (MetS) denotes a clustering of risk factors that may affect nitric oxide (NO) bioavailability and predispose to cardiovascular diseases, which are delayed by exercise training. However, no previous study has examined how MetS affects markers of NO formation, and whether exercise training increases NO formation in MetS patients. Here, we tested these two hypotheses. We studied 48 sedentary individuals: 20 healthy controls and 28 MetS patients. Eighteen MetS patients were subjected to a 3-month exercise training (E+group), while the remaining 10 MetS patients remained sedentary (E-group). The plasma concentrations of nitrite, cGMP, and ADMA (asymmetrical dimethylarginine: an endogenous nitric oxide synthase inhibitor), and the whole blood nitrite concentrations were determined at baseline and after exercise training using an ozone-based chemiluminescence assay, and commercial enzyme immunoassays. Thiobarbituric acid reactive species (TBA-RS) were measured in the plasma to assess oxidative stress using a fluorometric method. We found that, compared with healthy subjects, patients with MetS have lower concentrations of markers of NO formation, including whole blood nitrite, plasma nitrite, and plasma cGMP, and increased oxidative stress (all P < 0.05). Exercise training increased the concentrations of whole blood nitrite and cGMP, and decreased both oxidative stress and the circulating concentrations of ADMA (both P < 0.05). These findings show clinical evidence for lower endogenous NO formation in patients with MetS, and for improvements in NO formation associated with exercise training in MetS patients. (C) 2008 Elsevier Inc. All rights reserved.

alpha 1-acid glycoprotein and alpha 1-antitrypsin as early markers of treatment response in patients receiving the intensive phase of tuberculosis therapy

The identification of early markers that predict the response to anti-tuberculosis treatment would facilitate evaluation of new drugs and improve patient management. This study aimed to determine whether selected acute phase proteins and micronutrients measured at the time of diagnosis and during the first weeks of treatment could predict treatment responses during the 2-month standard intensive phase of therapy. For this purpose, alpha 1-antitrypsin, alpha 1-acid gtycoprotein, alpha 2-macroglobutin, C-reactive protein, C3, C4, zinc, copper and selenium concentrations were measured in Brazilian patients with smear-positive tuberculosis at the time of diagnosis and 1, 3, 5 and 8 weeks after initiation of therapy. Patients were classified into fast (n = 29), intermediate (n = 18) and slow responders (n = 10) if they were smear-negative at 3, 5 or 8 weeks of treatment. alpha 1-acid gtycoprotein on enrolment and 1 week of treatment, alpha 1-antitrypsin at week 1 and C-reactive protein and C3 after 3 weeks of therapy were higher in slow responders than in fast responders. alpha 1-antitrypsin and alpha 1-acid glycoprotein may be helpful in predicting treatment response at the time of initiation of therapy, and could be used as early markers to identify patients with an increased likelihood of treatment failure. (C) 2008 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.

Subchondral Cystlike Lesions Develop Longitudinally in Areas of Bone Marrow Edema-like Lesions in Patients with or at Risk for Knee Osteoarthritis: Detection with MR Imaging-The MOST Study

Purpose: To assess the association of prevalent bone marrow edema-like lesions (BMLs) and full-thickness cartilage loss with incident subchondral cyst-like lesions (SCs) in the knee to evaluate the bone contusion versus synovial fluid intrusion theories of SC formation. Materials and Methods: The Multicenter Osteoarthritis study is a longitudinal study of individuals who have or are at risk for knee osteoarthritis. The HIPAA-compliant protocol was approved by the institutional review boards of all participating centers, and written informed consent was obtained from all participants. Magnetic resonance images were acquired at baseline and 30-month follow-up and read semiquantitatively by using the Whole-Organ Magnetic Resonance Imaging Score system. The tibiofemoral and patellofemoral joints were subdivided into 14 subregions. BMLs and SCs were scored from 0 to 3. Cartilage morphology was scored from 0 to 6. The association of prevalent BMLs and full-thickness cartilage loss with incident SCs in the same subregion was assessed by using logistic regression with mutual adjustment for both predictors. Results: A total of 1283 knees were included. After adjustment for full-thickness cartilage loss, prevalent BMLs showed a strong and significant association with incident SCs in the same subregion, with an odds ratio of 12.9 (95% confidence interval [CI]: 8.9, 18.6). After adjustment for BMLs, prevalent full-thickness cartilage loss showed a significant but much less important association with incident SCs in the same subregion (odds ratio, 1.4; 95% CI: 1.0, 2.0). There was no apparent relationship between severity of full-thickness cartilage loss at baseline and incident SCs. Conclusion: Prevalent BMLs strongly predict incident SCs in the same subregion, even after adjustment for full-thickness cartilage loss, which supports the bone contusion theory of SC formation. (C) RSNA, 2010

Developing human minor salivary glands: morphological parallel relation between the expression of TGF-beta isoforms and cytoskeletal markers of glandular maturation

Morphogenesis of salivary glands involves complex coordinated events. Synchronisation between cell proliferation, polarisation and differentiation, which are dependent on epithelial-mesenchymal interactions and on the microenvironment, is a requirement. Growth factors mediate many of these orchestrated biological processes and transforming growth factor-beta (TGF-beta) appear to be relevant. Using immunohistochemistry and immunofluorescence, we have mapped the distribution of TGF-beta 1, 2 and 3 and compared it with the expression of maturation markers in human salivary glands obtained from foetuses ranging from weeks 4 to 24 of gestation. TGF-beta 1 first appeared during canalisation stage in the surrounding mesenchyme and, in the more differentiated stages, was expressed in the cytoplasm of acinar cells throughout the adult gland. TGF-beta 2 was detected since the bud stage of the salivary gland. Its expression was observed in ductal cells and increased along gland differentiation, TGF-beta 3 was detected from the canalisation stage of the salivary gland, being weakly expressed on ductal cells, and it was the only factor detected on myoepithelial cells. The data suggest that TGF-beta have a role to play in salivary gland development and differentiation.

The success of endosseous implants in human immunodeficiency virus-positive patients receiving antiretroviral therapy A pilot study

Background. In a pilot study, the authors aimed to determine the success rate of dental implants placed in patients who were positive for human immunodeficiency virus (HIV) and were receiving different regimens of highly active anti-retroviral therapy (HAART). They considered patients` levels of cluster of differentiation (CD) 4(+) cells and viral load, and they attempted to verify whether patients with baseline biochemical signs of bone mineral density loss could experience osseointegration impairment. Materials and Methods. One of the authors, a dentist, placed dental implants in the posterior mandibles of 40 volunteers, divided into three groups: one composed of HIV-positive patients receiving protease inhibitor (PI)-based HAART; a second composed of HIV-positive patients receiving nonnucleoside reverse transcriptase inhibitor based HAART (without PI); and a control group composed of HIV-negative participants. The authors assessed pen-implant health six and 12 months after implant loading. They analyzed the success of the implants in relation to CD4(+) cell counts, viral load and baseline pyridinoline and deoxypyridinoline values. Results. The authors followed 59 implants for 12 months after loading. Higher baseline levels of pyridinoline and deoxypyridinoline found in HIV-positive participants did not interfere with osseointegration after 12 months of follow-up. Average pen-implant bone loss after 12 months was 0.49 millimeters in group 1, 0.47 mm in group 2, and 0.55 mm in the control group. Conclusions. The placement of dental implants in HIV-positive patients is a reasonable treatment option, regardless of CD4(+) cell count, viral load levels and type of antiretroviral therapy. Longer, follow-up periods are necessary to ascertain the predictability of the long-term success of dental implants in these patients. Clinical Implications. Limited published scientific evidence is available to guide clinicians in regard to possible increased risks associated with dental implant placement in HIV-positive patients.

Assessment of the Availability of Bone Volume for Grafting in the Donor Retromolar Region Using Computed Tomography: A Pilot Study

Purpose: The purpose of this study was to evaluate the area and volume of bone available for grafting in a donor retromolar region using computed tomography (CT). Materials and Methods: Ten patients previously scanned by multislice CT were selected for evaluation. Images from partially and completely dentate patients at least 18 years of age were included in the study; those from patients with impacted or erupted third molars or intrabony lesions in the study area were not included. Computer software with appropriate tools was used to handle the images. Two calibrated observers made measurements separately. Safety margins in relation to the lingual cortex, the base of mandible, and the alveolar canal were established in each cross-section of the CTs. Measurements were done by using cross-sectional views, and the results were calculated after three-dimensional reconstruction, providing area and volume data. Results: The mean area of bone available for grafting was 8.12 cm(2) ( range, 0.00 to 13.60 cm(2)) and 8.32 cm(2) ( range, 0.00 to 14.30 cm(2)) for observers 1 and 2, respectively. Mean available bone volume for grafting was 0.79 cm(3) ( range, 0.00 to 1.50 cm(3)) for observer 1 and 0.85 cm(3) ( range, 0.00 to 1.60 cm(3)) for observer 2. Interobserver analysis showed substantial agreement. Conclusion: The retromolar region showed a wide variety of anatomic differences among patients. Three-dimensional multislice CT allows reproducible measurements of the area and volume of the retromolar region. Int J Oral Maxillofac Implants 2010; 25: 374-378

Assessment of linear measurements of bone for implant sites in the presence of metallic artefacts using cone beam computed tomography and multislice computed tomography

The objective was to evaluate the influence of dental metallic artefacts on implant sites using multislice and cone-beam computed tomography techniques. Ten dried human mandibles were scanned twice by each technique, with and without dental metallic artefacts. Metallic restorations were placed at the top of the alveolar ridge adjacent to the mental foramen region for the second scanning. Linear measurements (thickness and height) for each cross-section were performed by a single examiner using computer software. All mandibles were analysed at both the right and the left mental foramen regions. For the multislice technique, dental metallic artefact produced an increase of 5% in bone thickness and a reduction of 6% in bone height; no significant differences (p > 0.05) were detected when comparing measurements performed with and without metallic artefacts. With respect to the cone-beam technique, dental metallic artefact produced an increase of 6% in bone thickness and a reduction of 0.68% in bone height. No significant differences (p > 0.05) were observed when comparing measurements performed with and without metallic artefacts. The presence of dental metallic artefacts did not alter the linear measurements obtained with both techniques, although its presence made the location of the alveolar bone crest more difficult.

Expression of bone resorption regulators (RANK, RANKL, and OPG) in odontogenic tumors

Objective. To investigate the expression of bone resorption regulators (receptor activator of nuclear factor kappa B [RANK], RANK ligand [RANKL], and osteoprotegerin [OPG]) in calcifying cystic odontogenic tumor (CCOT), adenomatoid odontogenic tumor (AOT), calcifying epithelial odontogenic tumor (CEOT), odontogenic myxoma (OM), and ameloblastic fibroma (AF). Study design. The expression of these mediators was evaluated by means of immunohistochemistry. Results. All specimens demonstrated positive immunoreactivity to RANK, RANKL, and OPG. The quantification of these mediators in epithelium revealed a similar pattern of expression for RANKL and OPG in CCOT, AOT, CEOT, and AF. With regard to stromal/mesenchymal cells, the majority of AOT and CCOT cases showed a higher content of OPG than RANKL, whereas CEOT, OM, and especially AF had a tendency to present a greater content of RANKL than OPG. Conclusion. Our data indicate that the CCOT, AOT, CEOT, OM, and AF cell constituents express key regulators of bone metabolism that might locally modulate tumor-associated bone resorption. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;106:548-55)

Biomechanical and Microscopic Response of Bone to Titanium Implants in the Presence of Inorganic Grafts

This study evaluated the biomechanical and microscopic response of previously grafted bone to titanium implants. The lower incisors of 16 rabbits were surgically extracted, and bilateral perforations communicating with the remaining sockets were created distally. A socket/perforation defect on each mandible was chosen at random to be immediately filled with a xenogenic graft, whereas the contralateral perforation was left to heal naturally and served as a paired control. After 60 days, titanium implants were installed in the previously operated areas. After periods of 2 and 6 months, the animals were killed, and the force necessary to retrieve implants as well as the bone-implant contact (BIC) and bone mass (BM) were quantified and statistically compared by 2-way analysis of variance and Tukey`s test (alpha = .05). No significant differences in removal torque were observed, either by time or by treatment condition. Differences in BIC and BM between experimental and control groups were not statistically significant through the intervals studied (P < .05). The presence of a xenogenic graft did not influence the microscopic tissue response to titanium implants or fixation into newly formed or mature bone.

Morphodigital study of bone quality in the mandibular angle in patients with third molar impacted

The aim of this study was to analyze if the presence of impacted third molars, and their positions in the mandibular angle, can change the bone quality in this area, considering the measure of the cortical thickness in this region as representative or not for mandible fracture risk. Software was used to analyze 50 digital images from panoramic radiographs of patients who had one or two impacted third molars in the mandible, and 30 digital images of patients with agenesis of the mandibular third molar. The thickness of the cortical region of the mandible was measured; it was possible to draw a parallel line to the posterior portion of the mandible and a parallel line to the body of this bone on each side of the image. At the intersection of these lines near the distal portion of the second molar, another line was set up to serve as reference in the cortical thickness measurement. It could be concluded that the cortical thickness of the mandibular angle in male patients without impacted third molars was greater than the thickness in patients with these teeth, and no difference in thickness was found for the female group.

Inverse relationship between markers of nitric oxide formation and plasma matrix metalloproteinase-9 levels in healthy volunteers

Background: Nitric oxide (NO) is a major regulator of cardiovascular homeostasis and has anti-atherogenic properties. Reduced NO formation is associated with endothelial dysfunction and with cardiovascular risk factors. Although NO downregulates the expression and activity of the pro-atherogenic enzyme matrix metalloproteinase-9 (MMP-9), no previous clinical study has examined whether endogenous NO formation is inversely associated with the circulating levels of pro-MMP-9, which are associated with cardiovascular events. We examined this hypothesis in 175 healthy male subjects who were non-smokers. Methods: To assess NO bioavailability, the plasma concentrations of nitrite, nitrate, and cGMP were determined using an ozone-based chemiluminescence assay and an enzyme immunoassay. Pro-MMP-9 and pro-MMP-2 levels were measured in plasma samples by gelatin zymography. Results: We found significant negative correlations between pro-MMP-9 levels and plasma nitrite (P=0.035, rs=-0.159), nitrate (P=0.040, rs=-0.158), and cGMP (P=0.011, rs=-0.189) concentrations. However, no significant correlations were found between pro-MMP-2 levels and the plasma concentrations of markers of NO bioavailability (all P>0.05). Conclusions: There is an inverse relationship between markers of NO formation and plasma MMP-9 levels. This finding may shed some light on the possible mechanisms involved in the increased cardiovascular risk of apparently healthy subjects with low NO bioavailability or high circulating levels of pro-MMP-9. (C) 2008 Elsevier B.V. All rights reserved.

Effects of species turnover on reserve site selection in a fragmented landscape

Changes in species composition is an important process in many ecosystems but rarely considered in systematic reserve site selection. To test the influence of temporal variability in species composition on the establishment of a reserve network, we compared network configurations based on species data of small mammals and frogs sampled during two consecutive years in a fragmented Atlantic Forest landscape (SE Brazil). Site selection with simulated annealing was carried out with the datasets of each single year and after merging the datasets of both years. Site selection resulted in remarkably divergent network configurations. Differences are reflected in both the identity of the selected fragments and in the amount of flexibility and irreplaceability in network configuration. Networks selected when data for both years were merged did not include all sites that were irreplaceable in one of the 2 years. Results of species number estimation revealed that significant changes in the composition of the species community occurred. Hence, temporal variability of community composition should be routinely tested and considered in systematic reserve site selection in dynamic systems.