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Biomedical subjects

J D Langdon

Publications and source records attributed to J D Langdon.

At least 55 records · Page 3Linked to original sources
PubMed1991

Titanium mesh (TiMesh) osteosynthesis: a fast and adaptable method of semi-rigid fixation.

Titanium mesh has been used in the USA for the fixation of fractures of the facial skeleton since the Vietnam war. Despite the increasing use of titanium mesh osteosynthesis for trauma, orthognathic and reconstructive surgery in the USA, it is only in recent years that it has gained acceptance in Europe. This paper appraises the original titanium mesh osteosynthesis system (TiMesh) in a wide range of surgical contexts in the maxillofacial region. It has been found to be quick and reliable in placement, highly adaptable and to have considerably reduced the operating time. Its further potential advantages in reducing stress-shielding and improving functional bone healing due to its semi-rigid nature are discussed.

Bone Screws↗
PubMed1991

Complications of pharyngostomy.

An account is given of a fatal complication following the use of a pharyngostomy feeding tube. The literature on this topic is reviewed with regard to complications. Of the 671 patients that have been reported previously there have been no fatal or serious complications and minor complications were reported in only 42 patients. We regard the technique of pharyngostomy to be safe but recommendations are made to avoid the complication reported here.

Aged↗
PubMed1991

Temporomandibular joint eminence augmentation by down-fracture and inter-positional cartilage graft. A new surgical technique.

A new surgical technique for the treatment of recurrent temporomandibular joint subluxation or dislocation is described. Following a horizontal osteotomy and down-fracture of the articular eminence an inter-positional bovine cartilage xenograft is inserted in order to augment the vertical height of the eminence. The procedure combines simplicity with minimal post-operative morbidity. The increase in eminence height is both predictable and stable.

Cartilage↗
PubMed1991

The inferiorly based masseter muscle flap: anatomical basis for its use in head and neck reconstructive surgery.

The aim of this study was to investigate and elucidate the anatomical basis for the use of the inferiorly based masseter muscle flap in the reconstruction of oropharyngeal defects after ablative surgery. The anatomy of the masseter muscle, with particular emphasis on its blood supply, was studied using plain and coloured resin injected dissections and a series of digital subtraction angiograms and external carotid arteriograms. Both techniques were demonstrated to be reliable and effective means of anatomical investigation of blood vessels. The vascular anatomy of the masseter muscle and the anatomical and angiological results as well as a case report are described. The masseter muscle, when used as an inferiorly based flap, provides the necessary bulk for reconstruction of moderate size defects in the lateral border of the tongue, posterior floor of the mouth, retromolar trigone, anterior tonsillar pillars and lateral pharyngeal wall. Although the masseter muscle has small dimensions, it offers a reliable method of reconstruction in selected defects without the disadvantages of cosmetic and functional loss.

Angiography, Digital Subtraction↗
PubMed1991

Secondary alveolar bone grafting in clefts of the lip and palate.

A short review of the literature is presented outlining the role of alveolar bone grafting in cleft patients. An analysis of a series of 47 secondary alveolar bone grafts in 34 patients is presented. The age range was 7-24 years. At the time of evaluation, 30 canines were in final occlusion and good alveolar bone levels were present in 83% of patients. Of the 13 bilateral cases (26 clefts), 14 canines were in final occlusion and all cases had good alveolar bone levels. No major complications were encountered. The graft was completely resorbed in 3 cases (6.4%) only.

Adolescent↗
PubMed1990

A preliminary report using oxethazaine--a potential new dental local anaesthetic.

Oxethazaine is the most potent local anaesthetic in use. It is claimed to be 2000 times more potent than lignocaine and 500 times more potent than cocaine as assessed in rabbits eyes. Currently, oxethazaine is used in an antacid preparation for the topical relief of pain in conditions such as hiatus hernia, where the local pH is very low. Since oxethazaine is active in an acidic environment, it was decided to use oxethazaine, in a pilot study of 20 patients requiring minor oral surgery procedures, at a concentration of 0.1% at pH 3, to assess its value in achieving dental local anaesthesia. It was found that the local anaesthesia achieved was sufficient in all patients to allow the operative procedure to proceed. In two of the patients, who presented with acute periapical pathology, satisfactory local anaesthesia was achieved with 0.1% oxethazaine following a failure with lignocaine 2% and 1:80,000 adrenaline. The duration of anaesthesia was found to be similar to the average achieved with lignocaine 2% and 1:80,000 adrenaline.

Adult↗
PubMed1990

Leukotriene B4 and oral cancer.

The quantitation of leukotriene B4 (LTB4) in induced squamous cell carcinoma (SCC) of the Syrian hamster cheek pouch and histologically proven human oral SCC was investigated by a combination of reverse phase-high performance liquid chromatography (RP-HPLC) and radioimmunoassay (RIA). Healthy tissue obtained from these same patients and animals treated with vehicle alone were used as controls. From both animal and human studies our results show a 10 to 30 fold increase in the levels of LTB4 found in tumour compared to control tissue. Furthermore, this dihydroxy acid was not detected in the mucosal tissue of normal subjects undergoing routine surgery. Since LTB4 is a potent inflammatory mediator and modulator of immune responses, its presence at biologically active concentrations in human squamous cell carcinoma suggests a possible role in the pathogenesis of head and neck cancer.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1990

Is skin necessary for intraoral reconstruction with myocutaneous flaps?

Intraoral defects may be reconstructed in many ways following cancer resection. Following the advent of the myocutaneous flap, this has been very much the mainstay in intraoral reconstructive surgery. Although it has proved to be a reliable flap it has certain innate disadvantages which can often be attributed to the skin component of the flap. This paper attempts to make a case for using muscle-only pedicle flaps such as pectoralis major, masseter transfer and latissmus dorsi flaps.

Aged↗
PubMed1989

Protective effects of viscous solutions in phacoemulsification and traumatic lens implantation.

We compared the endothelial protection offered by 1% hyaluronate sodium (Healon), 3% hyaluronate sodium and 4% chondroitin sulfate (Viscoat), and a nonviscous irrigating solution (BSS Plus) during phacoemulsification with and without traumatic intraocular lens implantation. Vital-dye staining and scanning electron microscopy were used to determine acute damage to rabbit corneal endothelium. Cell damage during phacoemulsification alone was not significantly different from that in unoperated controls (12.5%). Cell damage after traumatic lens insertion was significantly greater in the groups treated with BSS Plus (76.2%) and Healon (41.4%) than in either paired Viscoat-treated group (21.1% and 17.4%, respectively). Viscoat (but not Healon) was noted to be adherent to the cornea at the end of the procedure in one third of the cases, indicating that Viscoat remains in the anterior chamber during surgery. We attribute this to chondroitin sulfate's newtonian characteristics, allowing it to maintain viscosity in the face of high flow rates.

Animals↗
PubMed1989

Multiple primaries in mouth cancer--the price of success.

Successful locoregional control in the treatment of oral cancer has been achieved at the expense of an increase in the occurrence of distant metastases and the emergence of second primary tumours. The head and neck are the commonest sites for second primaries which occur in 10 to 20% of patients. This study represents a detailed prospective analysis of 105 oral squamous cell carcinomas which could be followed-up until death or March 1987. Recently, interest has been focused on the role of screening such patients using triple endoscopy not only at initial diagnosis and assessment of the index tumour but also at follow-up after definitive treatment. However, the outlook for these patients is so poor, as confirmed by this study, that screening of frail elderly patients is hard to justify.

Adult↗
PubMed1989

Production of TGF-alpha and TGF-beta by cultured keratinocytes, skin and oral squamous cell carcinomas--potential autocrine regulation of normal and malignant epithelial cell proliferation.

Transforming growth factors have a wide range of biological activities related to cell proliferation and differentiation. In general TGF-alpha promotes cell proliferation while TGF-beta may stimulate or inhibit proliferation depending on the cell type and growth factor environment. Cultured human keratinocytes, skin and oral squamous cell carcinomas were analysed for the presence of transcripts and protein for the transforming growth factors alpha & beta. Both growth factors were detected in cultured keratinocytes (which have receptors for and respond to both ligands), and in medium conditioned by these cells. Additionally transcripts for TGF-alpha were found preferentially in the basal, proliferative compartment of cultured keratinocytes. Similarly both growth factors were detected in oral squamous cell carcinomas and a highly significant inverse correlation was found between the levels of TGF-alpha and the epidermal growth factor receptor in these tumours. The data for TGF-alpha are consistent with the existence of an autocrine growth control loop influencing cell proliferation in both a normal cell type and malignant epithelial tissues, a process that in keratinocytes and responsive squamous cell carcinomas could be modulated by TGF-beta.

Carcinoma, Squamous Cell↗
PubMed1988

Expression of epidermal growth factor receptor on oral squamous cell carcinoma.

The expression of the receptor for epidermal growth factor (EGF) in normal oral mucosa, papillomas and squamous cell carcinoma (SCC) has been determined by immunohistology and autophophorylation studies. Immunoreactive receptor was localised using two antibodies which recognise the receptor; EGFR1 which reacts with sequences in the external domain of the receptor and F4 which recognises sequences in the internal domain. EGFR was present on basal, suprabasal and some spinous cells of normal oral mucosa. Regional variation in the distribution of receptor was apparent. A similar pattern of receptor expression was seen on oral papillomas. The distribution and intensity of epidermal growth factor receptor (EGFR) expression varied between 20 patients with oral SCC. The staining patterns seen with the two antibodies were similar on all tissue types. The protein tyrosine-kinase activity of the receptor present on eight oral SCC was also examined by immunoprecipitation and autophosphorylation studies. This procedure also demonstrated variations in the amount of functional EGFR in these tumours. There was no significant correlation between the level of EGFR expression and tumour behaviour.

Carcinoma, Squamous Cell↗
PubMed1988

Tumours of the head and neck in children. A clinico-pathological analysis of 1,007 cases.

Tumours of the head and neck in children are uncommon, representing only 2-3% of all head and neck tumours. During the twenty year period 1964-1983, 12,876 childhood tumours were submitted for pathological diagnosis. Of these 1,007 (7.8%) were in the head and neck region, and it is this group that has been analysed. 30.6% (308 cases) were malignant neoplasms, 27.8% (280 cases) were benign neoplasms, 24.2% (244 cases) presented as tumour-like conditions and 17.4 (175 cases) were dysplasias arising from embryonal remnants. The overall sex ratio was 1.5:1 in favour of males. Lymphomas accounted for 15.9% overall (52.3% of the malignant neoplasms). Of benign tumours, haemangiomas were the most frequent (38.5%) and of the tumour-like conditions, dermoid and epidermoid cysts accounted for 36.1%. Of the embryonal remnant dysplasias, thyroglossal duct cysts accounted for 71.4%.

Adolescent↗