Biomedical subjects

D Quteish

Publications and source records attributed to D Quteish.

5 recordsLinked to original sources

PubMed1992

The use of irradiated-crosslinked human collagen membrane in guided tissue regeneration.

Irradiated glutaraldehyde-crosslinked human collagen membrane was evaluated for its effects on new attachment formation in clinical trials, using the principle of guided tissue regeneration (GTR). 19 adult periodontitis patients with 52 matched bilateral periodontal defects received scaling and polishing with oral hygiene instruction. The bilateral periodontal defects were treated by reflecting a flap with collagen membrane (test) or flap reflection alone (control). Plaque (P1I) and gingival index (GI) scorings, probing pocket depth (PPD) and probing attachment level (PAL) along with classification of furcation involvement (FI) and bony defects were made at pre- and post surgery (6 weeks, 3 and 6 months). Improvement of P1I and GI scores was seen in both test and control sites following the surgical therapy. Reductions in PPD and PAL were significantly (p less than 0.001) more pronounced at 6 months in the test sites compared to the controls. The 2 Class I furcations in the graft-treated teeth showed complete resolution, while the corresponding furcations in the control teeth showed incomplete closure. The use of human collagen membrane based on the GTR technique for treatment of human periodontal defects provided greater gain of clinical attachment than when flap surgery alone was undertaken.

Adult↗

PubMed1991

Guided tissue regeneration.

One of the main goals of periodontal therapy is the predictable regeneration of the periodontium by allowing repopulation of periodontal ligament cells into the wound area after surgery and preventing the colonisation of the exposed root surface with epithelial, gingival, and bone cells. In order to achieve this, emphasis has been placed on the use of barrier materials in the form of semipermeable membranes which are interposed between the mucoperiosteal flap and the bone and tooth surfaces during surgery. This technique is known as 'guided tissue regeneration' (GTR) and this article looks at the theory and practice of GTR, as well as reviewing the use of non-resorbable membrane materials such as expanded polytetrafluor-ethylene and ethyl cellulose, and resorbable materials such as collagen and polylactic acid.

Biodegradation, Environmental↗

PubMed1991

Light and electron microscopic evaluation of biocompatibility, resorption and penetration characteristics of human collagen graft material.

This study was initiated to test the biocompatibility, resorption and penetration characteristics of human collagen graft material in vitro and in vivo using light (LM) and electron microscopy (EM). To study this relationship, pieces of glutaraldehyde cross-linked collagen sponges (1 x 1 x 0.5 cm), were: (1) cultured in sterile Petri dishes with human gingival fibroblasts and human periodontal ligament fibroblasts for 2 weeks; (2) implanted in subcutaneous pockets made in both thighs (total 20 sites) of 10 Sprague-Dawley rats for 7-56 days. The behaviour of the growth of the fibroblasts was studied by inverted light microscopy (LM), then tissue culture specimens were studied from without and within using low-temperature scanning electron microscopy (LTSEM). Blocks obtained from the graft sites of the rat were processed for LM and transmission EM. Long-term LM observations showed attachment and random orientation of cells on and around the collagen sponge in culture during the first 48 h. Between 7 and 14 days, the majority of the cells adjacent to the sponge were orientated at right angles to its margin with their long axes approximately parallel to each other. The LTSEM revealed that large numbers of HGF and HPLF grew onto the collagen sponges, but no cellular penetration to the middle of the sponge was seen. LM and TEM of the rat specimens showed a cellular reaction to the collagen graft, as well as slow resorption, and fibroblast invasion of the graft at 6-8 weeks. It was concluded that the human collagen graft was biocompatible with HGF and HPLF, with penetration first observed at 42 days post-implantation. In the in vivo study, the collagen underwent slow resorption over a period of 8 weeks.

Animals↗

PubMed1991

Immune responses to implanted human collagen graft in rats.

Immunity to collagen implants may be mediated by cellular and humoral immune responses. To examine the possibility of such immunological reactivity and crossreactivity to collagen, 39 Sprague-Dawley rats (female, 10 weeks old, approximately 250 g wt) were implanted subcutaneously at thigh sites with crosslinked, freeze-dried human placental type I collagen grafts (4 x 4 x 2 mm) which had been irradiated (520 Gray) or left untreated. Blood was obtained by intracardiac sampling prior to implantation or from normal rats, and at various times afterwards when the animals were sacrificed. The sera from these animals were examined for circulating antibodies to human, bovine and rat tail (type I) collagens by enzyme-linked immunosorbent assay (ELISA). Also, the lymphoblastogenic responses of spleen lymphocytes from the irradiated collagen-implanted animals were assessed in culture by measuring thymidine uptake with autologous and normal rat sera in the presence of human and bovine type I collagens. Implantation of the irradiated and non-irradiated collagen grafts in rats led to a significant increase in the level of circulating antibodies to human collagen. Also antibody to bovine and rat tail collagens was detectable in the animals implanted with irradiated collagen grafts but at a lower level than the human collagen. There was a raised lymphoblastogenic response to both human and bovine collagens. The antibody level and lymphoblastogenesis to the tested collagens gradually decreased towards the end of the post-implantation period.

Animals↗

PubMed1990

Development and testing of a human collagen graft material.

Human Type I collagen was extracted from placenta using pepsin and salt fractionation. The collagen was characterized by SDS-PAG electrophoresis dispersed in acidic medium, freeze-dried, and cross-linked in an 0.25% glutaraldehyde solution pH 4.5 for 2 days. After washing for 7 days and freeze drying the resultant collagen sponge was tested with regard to mechanical, physical, enzymatic degradation properties and biological responses. The modulus of elasticity was found to be 289 +/- 10 g/mm2 and the sponge was insoluble in water, buffered saline, or tissue culture medium over a period of 6 weeks with swelling occurring at less than 5% of volume. The sponge had a high fluid binding capacity, amounting to 56 +/- 5 mL tissue culture medium per gram of dry weight. Bacterial collagenase produced slow degradation of the sponge with complete disappearance by 24 h only when high concentrations (200 units enzyme per mg of the collagen sponge) were used. Cytotoxicity studies using human gingival and periodontal ligament fibroblasts revealed less than 5% apparent cytotoxicity or proliferation. Subcutaneous implantation was followed by resorption and vascularization over a period of 6-8 weeks. It was concluded that the collagen sponge prepared from human Type I collagen has potential as a graft material in oral surgical procedures.

Animals↗