24 research outputs found
Brief Announcement: Characterizing Demand Graphs for (Fixed-Parameter) Shallow-Light Steiner Network
No full textWe consider the Shallow-Light Steiner Network problem from a fixed-parameter perspective. Given a graph G, a distance bound L, and p pairs of vertices {(s_i,t_i)}_{i in [p]}, the objective is to find a minimum-cost subgraph G' such that s_i and t_i have distance at most L in G' (for every i in [p]). Our main result is on the fixed-parameter tractability of this problem for parameter p. We exactly characterize the demand structures that make the problem "easy", and give FPT algorithms for those cases. In all other cases, we show that the problem is W[1]-hard. We also extend our results to handle general edge lengths and costs, precisely characterizing which demands allow for good FPT approximation algorithms and which demands remain W[1]-hard even to approximate
Effect of miswak extract on healthy human dentin an in vitro study
No full textThe purpose of this study was to compare the texture of dentin surfaces after the application of saline, aqueous and alcohol-derived miswak extracts using different modes of application and exposure times. It was concluded that alcohol derived miswak extract at pH of 2.5 to 2.9, selectively removed the smear layer from the dentin surface exposing the dentinal tubules. This result was in contrast to burnishing dentin surface with aqueous - miswak extract of higher pH 6.3 to 6.6 or with saline, both of which partially removed the smear layer without dentinal tubules exposure. It cannot be excluded that the pH of the solutions used is an important factor in determining whether etching occurs.Corresponding Author:
Dr. Nadir Babay, Division of Periodontics, Department of Preventive Dental Sciences, College of Dentistry, King Saud University, PO Box 60169, Riyadh 11545, K.S.A. Email: [email protected]
The effect of EDTA on the attachment and growth of cultured human gingival fibroblasts on periodontitis-affected root surface
No full textThe purpose of the present study was to analyze the effects of 5% and 24% EDTA on the attachment of gingival fibroblasts to periodontally diseased root surfaces. A flat root surface was created on human teeth that were extracted due to severe periodontitis. The teeth were etched with the following concentrations of etylediaminetetraacetic acid (EDTA) for two minutes: 5% (group I) and 24% (group II). Group III was soaked in saline and served as a control. The specimens and fibroblasts were incubated in a culture medium for 24 hours each day for one and two weeks and photographed using scanning electron microscopy. Each specimen was examined for the migration of cells into the etched and non-etched root surface. No fibroblasts could be detected on the saline groups. More fibroblasts could attach to the surface treated with 24% EDTA than with 5% EDTA. It was concluded that supersaturated EDTA at 24% enhances the attachment of gingival fibroblasts to the root surface.Corresponding Author:
Dr. Babay Nadir
Associate Professor & Head of the Division of Periodontics, Department of Preventive Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
Email: [email protected]
Effect of various scaling and conditioning procedures onperiodontally affected Human root surfaces: a scanning electron microscopic study
No full textThe purpose of the present study was to investigate the appearance of periodontally involved root surfaces after hand scaling and after using two different piezoelectric ultrasonic scalers. Further, the root surfaces were examined by a scanning electron microscope after they have been treated with saline, saturated citric acid, saturated tetracycline hydrochloride or 8% EDTA for 3 minutes. Thirty-seven root specimens from the "diseased" part of nine periodontally-involved human permanent teeth were analyzed after they have been treated according to the above-mentioned procedures with corresponding controls (non-treated) in a randomized order. The observations made indicated no differences among the three scaling devices, but significant differences among etched, or chelated, and non-etched, or non-chelated, root surfaces with the former showing needle-pointed surfaces and crater formations.This study was registered with the College of Dentistry Research Center, Grant No. NF1289.Corresponding Author:
Dr. Nadir Babay, Department of Preventive Dental Sciences, King Saud University College of Dentistry, P.O. Box 60169, Riyadh 11545, Saudi Arabia. Email:[email protected]
The effect of tetracycline hydrochloride on the smear layer formed by various root planing modalities: A scanning electron microscopy study
No full textThe purpose of the present study was to examine the smear layer formation following different root planing modalities and its removal using tetracycline hydrochloride. Thirty-two periodontitis involved human teeth were randomly divided into 8 groups of 4 each.
Groups 1 & 2 were root planed with hand instrument (Gracey 11/12) while in groups 3 & 4, aflat diamond bur was used. In groups 5 & 6, the roots were scaled with a piezoelectric unit (Piezon) while in groups 7 & 8, a magnetostrlctive unit (Amdent) was used. Sixteen teeth (two in each group) were conditioned with tetracycline hydrochloride for 3 minutes while the other sixteen teeth were not conditioned and served as controls. The surfaces were examined by a scanning electron microscope. The results showed that root planing resulted in a smear covering the root surfaces, irrespective of the treatment modality. Tetracycline hydrochloride efficiently removed the smear layer with collagen fibers exposed to varying degrees.Corresponding Author:
Dr. Nadir Babay, Associate Professor, Head of Division of Periodontics
Department of Preventive Dental Sciences
College of Dentistry, King Saud University
PO Box 60169, Riyadh 11545, Saudi Arabia.
Email: [email protected]
Effective and affordable periodontal maintenance therapy
No full textMechanical and chemical antimicrobial intervention is the mainstay of preventive periodontal
therapy. Successful periodontal maintenance care depends upon the ability of dental professionals to combat periodontal infections and patient compliance with prescribed follow-up care. Since tooth brushing, flossing
and oral rinsing do not reach pathogens residing in furcations and at the depths of deep periodontal pockets,
adequate oral hygiene should include subgingival treatment with home irrigators or other appropriate self-care remedies in patients with increased pocket depths. I'ovidonc-iodine for professional use and diluted bleach
for self-care are iue\pensi\e and \aluable antimicrobial agents in periodontal maintenance. The present article outlines the prudent use of antimicrobial therapy in periodontal maintenance therapy.Corresponding Author:
Prof Nadir Babay, Associate Professor and Program Director of Postgraduate
Periodontics, Department Preventive Dentistry, College of Dentistry, King Saud University, P.O.Box 60169, Riyadh 11545, Saudi Arabia.
Email: [email protected]
Clinicopathologic significance of HLA-G and HLA-E molecules in Tunisian patients with ovarian carcinoma
No full textBACKGROUND:
The human leukocyte antigen (HLA)-G and HLA-E, non classical HLA class I molecules, have been highly implicated in immune tolerance. HLA-G and HLA-E molecules were proposed as putative markers of several advanced cancers. As a step towards a better understanding of ovarian carcinoma, we evaluated the expression of both HLA-G and HLA-E molecules and explored their prognostic implication.
METHODS:
HLA-G and HLA-E expression were studied by immunohistochemistry on ovarian carcinoma tissues. This expression was semi-quantitatively scored into four expression groups and correlated to clinicopathological parameters and patients' survival.
RESULTS:
HLA-G and HLA-E have been found to be highly expressed in ovarian carcinoma tissues (Respectively, 72.4% and 96.8%). They are frequently co-expressed. Univariate and multivariate analysis revealed that a positive HLA-G expression status in tumor tissue is a promising candidate parameter to predict disease recurrence in addition to the disease status in Tunisian patients with ovarian carcinoma. Moreover, the elevated HLA-E expression was associated with serous ovarian carcinoma subtype as well as with advanced stages of ovarian carcinoma.
CONCLUSION:
HLA-G and HLA-E are highly represented in ovarian carcinoma suggesting a potential association with progressive disease mechanism. HLA-G and HLA-E molecules might be new candidates' markers for ovarian carcinoma progression.
Copyright © 2018 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved
The nature of soft tissue attachment with acid-enzyme treated roots :
No full textPLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please log in with a valid BU account to access and click Download. If you are the author of this work and would like to make it publicly available, please contact [email protected] photographs included.Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1981 (Oral biology)Bibliography : leaves 124-147
HLA-E polymorphism and soluble HLA-E plasma levels in chronic hepatitis B patients
No full textChronic hepatitis B virus (HBV) infection occurs in association to a deregulation of immune system. Human leukocyte antigen E (HLA-E) is an immune-tolerant nonclassical HLA class I molecule that could be involved in HBV progression. To measure soluble (s) HLA-E in patients with chronic HBV hepatitis (CHB). We tested the potential association of HLA-E*01:01/01:03 A > G gene polymorphism to CHB. Our cohort consisted of 93 Tunisian CHB patients (stratified in CHB with high HBV DNA levels and CHB with low HBV DNA levels) and 245 healthy donors. Plasma sHLA-E was determined using enzyme-linked immunosorbent assay (ELISA). Genotyping was performed using polymerase chain reaction sequence-specific primer. No association between HLA-E*01:01/01:03 A > G polymorphism and HBV DNA levels in CHB patients was found. G/G genotype is less frequent in CHB patients without significance. sHLA-E is significantly enhanced in CHB patients compared with healthy controls (P = 0.0017). Stratification according to HBV DNA levels showed that CHB patients with low HBV DNA levels have higher sHLA-E levels compared with CHB patients with high HBV DNA levels. CHB patients with G/G genotype have enhanced sHLA-E levels compared with other genotypes (P = 0.037). This significant difference is maintained only for CHB women concerning G/G genotypes (P = 0.042). Finally, we reported enhanced sHLA-E in CHB patients with advanced stages of fibrosis (P = 0.032). We demonstrate, for the first time, the association of sHLA-E to CHB. Owing to the positive correlation of HLA-E*01:01/01:03 A > G polymorphism and the association of sHLA-E to advanced fibrosis stages, HLA-E could be a powerful predictor for CHB progression. Further investigations will be required to substantiate HLA-E role as a putative clinical biomarker of CHB.Chronic hepatitis B virus (HBV) infection occurs in association to a deregulation of immune system. Human leukocyte antigen E (HLA-E) is an immune-tolerant nonclassical HLA class I molecule that could be involved in HBV progression. To measure soluble (s) HLA-E in patients with chronic HBV hepatitis (CHB). We tested the potential association of HLA-E*01:01/01:03 A>G gene polymorphism to CHB. Our cohort consisted of 93 Tunisian CHB patients (stratified in CHB with high HBV DNA levels and CHB with low HBV DNA levels) and 245 healthy donors. Plasma sHLA-E was determined using enzyme-linked immunosorbent assay (ELISA). Genotyping was performed using polymerase chain reaction sequence-specific primer. No association between HLA-E*01:01/01:03 A>G polymorphism and HBV DNA levels in CHB patients was found. G/G genotype is less frequent in CHB patients without significance. sHLA-E is significantly enhanced in CHB patients compared with healthy controls (P=0.0017). Stratification according to HB..
Expression analysis of immune-regulatory molecules HLA-G, HLA-E and IDO in endometrial cancer
No full textHLA-G has been widely implicated in advanced cancers through different pathways of immunosuppression allowing tumor escape. Contrarily, HLA-E has a controversial role in the tumor escape from the immune system. IDO catabolic enzyme is known to be up-regulated in many tumors types allowing their immune escape. Based on these considerations, we investigated the expression of HLA-G, HLA-E and IDO molecules in endometrial cancer (EC) and their association with prognostic clinicopathologic parameters. Their expression were checked in tumoral and adjacent endometrial tissues. Both HLA-G and IDO immunostaining were significantly increased in EC tissues compared to normal residual endometrial glands (Mann Whitney U-test, p = 0.0001 and p = 0,020 respectively). However, HLA-E was highly expressed in tumoral tissues as well as in normal residual endometrial glands (respectively, 100% and 81.8%). Increased HLA-G expression levels were observed in high histological grade (grade 3), and in the non-endometrioid type 2 EC. Unexpectedly, patients with IDO Low expression had significantly impaired overall survival compared to patients with IDO High (log-rank p = 0.021). Conversely, HLA-E low expression was associated to an improved overall survival EC (log-rank p = 0.004). We concluded that, HLA-G and IDO are highly expressed in EC compared to adjacent normal endometrial tissues, that might be interesting for the EC outcome
