Third-molar development in relation to chronologic age in Turkish children and young adults

OBJECTIVE: To assess estimation of chronologic age based on the stages of third-molar development following the eight stages (A-H) method of Demirjian et al and to compare third-molar development by sex and age with results of previous studies. MATERIALS AND METHODS: The final sample consisted of 900 orthopantomograms from young Turkish subjects of known chronologic age (range, 8-25 years; mean age, 15.18 +/- 4.81 years) and sex (380 males with a mean age of 14.51 +/- 4.55; 520 females with a mean age of 15.67 +/- 4.94). Statistical analysis was performed using the Mann-Whitney U-test and the Wilcoxon test between sex and age. Regression analysis was performed to obtain regression formulas for dental age calculation with the chronologic age RESULTS: Statistically significant differences (P < .05) in third-molar development between males and females were revealed regarding the calcification stages D and G. Third-molar genesis was attained earlier in males than in females. Statistical analysis showed a strong correlation between age and third-molar development for males (r(2) = .65) and for females (r(2) = .61). New equations (Age = 8.92 + 1.50 Development stage) were derived for estimating chronologic age. CONCLUSION: The use of third molars as a developmental marker is appropriate, especially when comparing the obtained standard deviation with other skeletal age calculation techniques.     

The effect of varying Al2O3 percentage in hydroxyapatite/Al2O3 composite materials: morphological, chemical and cytotoxic evaluation

Hydroxyapatite (HA) and HA-alumina (HA/Al2O3) composites, with Al2O3 contents of 5, 10, 20, and 30%, were synthesized using a wet precipitation method and sintered at 900 and 1300 degrees C. We investigated the effect of sintering temperature and relative concentration of HA and Al2O3 on the chemical composition, surface morphology, and cytotoxicity of the composite powders. The XRD results show that in the 1300 degrees C composites, HA partially decomposed into CaO which combined with Al2O3 to form different calcium aluminates. For the 900 degrees C composites the CaO phase was not detected, though a Ca/P ratio larger than 1.67 measured by XPS suggests that CaO was present in trace amounts. SEM-EDX analysis indicated that the HA microstructure was affected by the sintering temperature, and this HA is present on the surface of Al2O3 particles. The cytotoxicity of the composites was assessed indirectly using the MTT assay. The short-term effect of leachables was quantified by exposing a L929 mouse fibroblast cell line to the degradation products released by the composites after immersion in the cell culture medium. Degradation products were less toxic to L-929 at lower extract concentrations (10, 50%) than at 100% concentration. Cell viability was also influenced by leachable size.     

Design of a biomimetic polymer-composite hip prosthesis

A new biomimetic composite hip prosthesis (stem) was designed to obtain properties similar to those of the contiguous bone, in particular stiffness, to allow normal loading of the surrounding femoral bone. This normal loading would reduce excessive stress shielding, known to result in bone loss, and micromotions at the bone-implant interface, leading to aseptic prosthetic loosening. The design proposed is based on a hollow substructure made of hydroxyapatite-coated, continuous carbon fiber (CF) reinforced polyamide 12 (PA12) composite with an internal soft polymer-based core. Different composite configurations were studied to match the properties of host tissue. Nonlinear three-dimensional analysis of the hip prosthesis was carried out using a three-dimensional finite element bone model based on the composite femur. The performance of composite-based hip and titanium alloy-based (Ti-6Al-4V) stems embedded into femoral bone was compared. The effect of core stiffness and ply configuration was also analyzed. Results show that stresses in composite stem are lower than those in Ti stem, and that the femoral bone implanted with composite structure sustains more load than the one implanted with Ti stem. Micromotions in the composite stem are significantly smaller than those in Ti stem over the entire bone-implant surface because of the favorable interfacial stress distribution.     

Activation/proliferation and apoptosis of bystander goat lymphocytes induced by a macrophage-tropic chimeric caprine arthritis encephalitis virus expressing SIV Nef

Caprine arthritis encephalitis virus (CAEV) is the natural lentivirus of goats, well known for its tropism for macrophages and its inability to cause infection in lymphocytes. The viral genome lacks nef, tat, vpu and vpx coding sequences. To test the hypothesis that when nef is expressed by the viral genome, the virus became toxic for lymphocytes during replication in macrophages, we inserted the SIVsmm PBj14 nef coding sequences into the genome of CAEV thereby generating CAEV-nef. This recombinant virus is not infectious for lymphocytes but is fully replication competent in goat macrophages in which it constitutively expresses the SIV Nef. We found that goat lymphocytes cocultured with CAEV-nef-infected macrophages became activated, showing increased expression of the interleukin-2 receptor (IL-2R). Activation correlated with increased proliferation of the cells. Interestingly, a dual effect in terms of apoptosis regulation was observed in exposed goat lymphocytes. Nef was found first to induce a protection of lymphocytes from apoptosis during the first few days following exposure to infected macrophages, but later it induced increased apoptosis in the activated lymphocytes. This new recombinant virus provides a model to study the functions of Nef in the context of infection of macrophages, but in absence of infection of T lymphocytes and brings new insights into the biological effects of Nef on lymphocytes.     

Myxoid plexiform fibrohistiocytic tumor without multinucleated giant cells

Plexiform fibrohistiocytic tumour is a rare soft-tissue tumour of intermediate malignancy. It is more prevalent in children and in young adults. We report a case of this tumour presenting as a nontender swelling on the shoulder of an 8-year-old girl. Clinically, the mass was subcutaneous and measured 2 cm in greatest diameter. The histopathological examination revealed a mesenchymal dermic and subcutaneous tumour composed of confluent nodules. These nodules were made of aggregates of histiocyte-like cells and concentric fascicles of spindle cells. The stroma was myxo?d or collagenous. This case was particular by the lack of giant cells and the focally myxoid background. The epidemiologic, clinicopathologic features and outcome of this lesion are discussed and similar published cases are reviewed.     

Evaluation of liver function by means of serum cytokeratin 18 and hepatocyte growth factor levels in patients with obstructive jaundice

Objective: To evaluate the serum levels of cytokeratin 18 (CK18) and hepatocyte growth factor (HGF) in obstructive jaundice patients before and after treatment and thereby to detect the possible role of CK18 and HGF in patients with obstructive jaundice.

Patients and methods: Forty patients who had obstructive jaundice and 40 healthy control subjects were included in the study. Patients were treated using percutaneous, endoscopic or surgical approaches. Blood samples were obtained at the day before and 7 days after the intervention for obstructive jaundice. Serum HGF and CK18 concentrations were determined by ELISA method.

Results: There were statistically significant decreases in HGF, CK18, total bilirubin and direct bilirubin serum levels, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase, and alkaline phosphatase activities and white blood cell count when compared with pre-treatment levels.

Conclusion: Evaluating pre- and post-treatment serum HGF and CK18 levels suggested that there was an apoptosis in obstructive jaundice patients and this apoptosis decreased after the decompression of the biliary tract. We also demonstrated that HGF levels were altered at biliary obstruction compared to healthy controls and the levels of this biomarker also decreased after decompression of biliary obstruction. We concluded that these biomarkers can be used as predictors of liver injury in biliary obstruction.     

Shifts in intestinal microbiota after duodenal exclusion favor glycemic control and weight loss: a randomized controlled trial

Background

In recent years, studies indicate gut microbiota as an important modulator in the pathophysiology of type 2 diabetes. Environmental and genetic factors interact to control the host's intestinal microbiota, triggering metabolic disorders such as obesity and insulin resistance.

ckshs expression is linked to cell proliferation in normal and malignant human lymphoid cells

Cyclin kinase sub‐units (CKS) are known to interact with cyclin‐dependent kinases (CDKs), but their functions are not completely understood and their expression in human tissues is not documented. For analyzing relationships of CKS with cell proliferation and/or with differentiation, we investigated the expression of ckshs1 and ckshs2 in normal and malignant human lymphoid cells. ckshs1 and ckshs2 expression appeared to be related to cell proliferation: (i) mRNAs increased with stimulation of normal peripheral‐blood lymphocytes, and from the G₁ to the SG₂M phase in elutriated cells; (ii) P9 proteins were also induced by lymphocyte stimulation and were localized in nucleus where phosphorylated forms of CDK1 were also found; (iii) in vitro, the phosphorylated forms of CDK1 and CDK2 were preferentially linked to CKS. Among 45 patients presenting acute or chronic lymphoid malignancy, ckshs1 and ckshs2 mRNAs varied in a similar way and were significantly correlated to cell proliferation (p < 0.0001). When analysis was restricted solely to acute lymphoblastic leukemia (ALL) this correlation was still found and ckshs1 and ckshs2 were significantly more expressed in T‐cell ALL than in B‐cell‐lineage ALL. These results confirm relationships between ckshs expression and cell proliferation, and pose the question of a link with cell differentiation. Int. J. Cancer 82:98–104, 1999. © 1999 Wiley‐Liss, Inc.     

Effects of bevacizumab administration on the hypoxia - induced pulmonary hypertension rat model

Background/aim Bevacizumab is a chemotherapeutic drug, which selectively binds to vascular endothelial growth factor (VEGF) and mainly inhibits angiogenesis and neovascularization. We aimed to study the possible effects of bevacizumab on right ventricular pressure (RVP), right ventricular hypertrophy, and VEGF, in hypoxia - induced pulmonary hypertension (PH) rat model.Materials and methods 24 adult Wistar Albino rats were randomly divided into four groups: control group - saline; Bevacizumab Group; PH Group; PH + Bevacizumab Group. In hypoxia - induced model, 10% oxygen and 90% nitrogen were applied in a plexiglas box for eight days to PH Group and PH + Bevacizumab Group. On day eight, RVPs were measured directly from the heart, and then animals were sacrificed. Heart and lung tissues were examined, and Fulton index was measured.Results RVP, Fulton index, and tissue VEGF scores were significantly lower in PH + Bevacizumab group than PH group: median (ranges), RVP, mmHg, 37.8 (33.0–39.0) and 32.3 (28.0–35.0), p: 0.01; Fulton index: 0.30 (0.29–0.33) and 0.25 (0.24–0.26), p: 0.003; tissue VEGF scores: 5.1 (4.8–5.3) and 4.0 (3.8 4.1), p: 0.004, respectively. Conclusion Bevacizumab, which is indeed an antineoplastic agent, might have a favorable effect on hypoxia - induced pulmonary hypertension.