Biomedical subjects

D J Kibblewhite

Publications and source records attributed to D J Kibblewhite.

5 recordsLinked to original sources

PubMed1996

Transforming growth factor-beta 1 in a guanidine-extracted demineralized bone matrix carrier rapidly closes a rabbit critical calvarial defect.

Transforming growth factor beta 1 (TGF-beta 1) is a polyfunctional regulatory cytokine that has been shown to have roles in extracellular matrix interactions, soft tissue healing, and osteogenesis. Twenty-five microL of recombinant human TGF-beta 1 was added to guanidine-extracted demineralized bone matrix carrier and the implants were used to fill a 14-mm osteoperiosteal critical calvarial defect in New Zealand white rabbit model. The defects were allowed to heal over 4 weeks and the degree of new bone formation was assess by radiodensitometry and undecalcified bone histomorphometry techniques. Implants with TGF-beta 1 showed complete bridging of the gap with new bone in all cases, while the controls showed fibrous tissue repair of the gap with little or no new bone formation. These results demonstrate the ability of TGF-beta 1 to induce new bone in a brief time period in an inactive carrier.

Animals↗

PubMed1996

TGF-beta 1 forms functionally normal bone in a segmental sheep tibial diaphyseal defect.

OBJECTIVE: Transforming growth factor-beta 1 (TGF-beta 1) is a polyfunctional regulatory cytokine that has been shown to have roles in extracellular matrix interactions, soft tissue healing, and osteogenesis. This study was undertaken to determine the efficacy of TGF-beta 1 in the formation of functionally normal bone in tibial-diaphyseal defects. METHOD: Seven hundred fifty micrograms of recombinant human TGF-beta 1 was added to a guanidine-extracted demineralised bone matrix (Gu-DBM) carrier and the implants were used to fill a 2.5 cm tibial diaphyseal defect in skeletally mature female sheep. The defects were allowed to heal over a 12-week period. After sacrifice, they were analyzed using four-point bending mechanical testing. RESULTS: Implants with TGF-beta 1 showed complete bony bridging of the defect and stress-strain curves similar to the normal contralateral limb, while implants with the carrier alone failed to bridge the gap. CONCLUSIONS: These results demonstrate the ability of TGF-beta 1 to induce new bone which has structural and functional characteristics similar to normal bone.

Animals↗

PubMed1993

Transforming growth factor-beta accelerates osteoinduction in a craniofacial onlay model.

Recombinant human transforming growth factor beta 1 was added to a demineralized bone matrix (DBM) paste, formed into cylinders and implanted onto the cranial periosteum of New Zealand White rabbits. The TGF-beta was added at doses of 0, 0.3, 3, 30 and 75 micrograms per implant. When the implants were removed after six weeks, histomorphometric analysis of the implants showed that TGF-beta induced significantly higher levels of trabecular bone formation than in the controls (mineralized bone area 6.0 +/- 0.8, 6.0 +/- 1.2, 5.6 +/- 1.0, 10.1 +/- 1.5, and 10.8 +/- 1.4 mm2, respectively, P < 0.05), TGF-beta also caused greater resorption of the demineralized bone matrix carrier (matrix area 7.2 +/- 0.9, 6.8 +/- 1.4, 3.7 +/- 0.9, 2.7 +/- 1.2, 0.9 +/- 0.5 mm2, respectively, P < 0.02). Measurements of the osteoid demonstrated a more active bone surface and there was evidence of rapid bone remodeling. Similar results were obtained using TGF-5 beta, a new hybrid molecule. These results demonstrate the capacity of transforming growth factor beta in accelerating osteoinduction.

Analysis of Variance↗

PubMed1990

A double-blind controlled study of the efficacy of cimetidine in the treatment of the cervical symptoms of gastroesophageal reflux.

Globus pharyngeus and post-nasal drip are common patient complaints encountered in general otolaryngologic practice. Although these complaints have been traditionally ascribed to stress and sinusitis respectively, recently it has been suggested that they are secondary to gastroesophageal reflux, either by a direct effect on the pharynx and posterior larynx or by referred sensation along vagal pathways from the lower esophagus. This reflux could alter the motor tone of the laryngoesophagus and contribute to the pathogenesis of dysphonias. If globus and post-nasal drip are secondary to gastroesophageal reflux, then reduction of stomach pH should reduce the frequency and severity of these complaints. To test these hypotheses in a clinical setting, a large population of patients with vocal disorders was analyzed for the incidence of these complaints. Twenty healthy patients with globus and/or postnasal drip were then entered in a double-blind random placebo-controlled study to assay the efficacy of cimetidine in treating these complaints. No significant difference was found between cimetidine and placebo.

Cimetidine↗

PubMed1988

Acute sphenoid sinusitis: management strategies.

Acute sphenoid sinusitis is an uncommon disease with a significant morbidity. This paper reviews 14 patients presenting with acute sphenoid sinusitis between 1978 and 1987. Fifty-seven percent of patients had signs of neurological or ophthalmological complications, and 29% were left with permanent disabilities. Delay in diagnosis and treatment resulted in a morbidity of 80%. The organism most commonly cultured was Staphylococcus aureus, followed by Streptococcus pneumoniae. Haemophilus influenza, and other streptococci. While a trial of medical therapy for 24 hours is warranted in uncomplicated cases, we recommend surgical drainage of the sinus if medical therapy fails, and for all patients with complications.

Adolescent↗