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Biomedical subjects

J D Langdon

Publications and source records attributed to J D Langdon.

At least 37 records · Page 2Linked to original sources
PubMed1996

Expression of bFGF, KGF and FGF receptors on normal oral mucosa and SCC.

Fibroblast growth factors (FGFs) are involved in the transmission of signals between the epithelia and connective tissue, and influence epidermal growth and differentiation. They are thought to be important in the restoration of normal tissues after injury and aberrant expression may also play a role in tumorigenesis. However, no information is available on the nature of cells within oral mucosa which synthesise and/or respond to FGFs. We have screened normal oral mucosa and oral squamous cell carcinoma (SCC) for expression of bFGF by immunohistology and northern analysis and used RT-PCR to look for transcripts for KGF and the high-affinity FGF receptors FGFR1 and FGFR2. Transcripts for bFGF were detected in normal and malignant oral mucosa and KGF within connective tissue elements. The predominant FGF receptor detected in the epidermis and oral mucosa was FGFR2 which binds KGF with greater affinity than bFGF. Production of KGF by connective tissue components and synthesis of the high-affinity KGF receptor, FGFR2, by oral keratinocytes provides circumstantial evidence for a paracrine growth control loop with KGF synthesised within the lamina propria or tumour stroma influencing the proliferation and maturation of both normal oral epithelium and SCC.

Base Sequence↗
PubMed1996

The role of angiogenesis in the spread of oral squamous cell carcinoma.

Microvessels were counted in 41 primary oral squamous cell carcinomas using JC70 antibody to PECAM (CD31). The counts were compared with clinical and pathological indicators of tumour behaviour including lymph node status, tumour stage, type of histological differentiation, size and velocity of tumour growth. Tumour microvessel counts correlated with lymph node metastasis (p < 0.001). This association was independent of tumour size, velocity and type of histological differentiation and when all the variables were analysed by multivariate analysis only vascular count showed a significant association with lymph node metastasis.

Carcinoma, Squamous Cell↗
PubMed1996

Frequent gene deletions in potentially malignant oral lesions.

Some oral cancers are preceded by premalignant lesions which include leucoplakia and erythroplakia. At present there are no reliable markers to identify lesions that may progress to malignancy. We have analysed 30 potentially malignant oral lesions for deletions at chromosomal regions that harbour tumour-suppressor genes for oral cancer. A total of 16 of 30 cases (53%) showed loss of heterozygosity (LOH) or allele imbalance at TP53, DCC, 3p21.3-22.1 or 3p12.1-13. These genetic alterations were detected in dysplastic lesions but not in histologically normal mucosa and may be early events in the carcinogenic process. A total of 64% of dysplastic lesions that recurred during the study showed LOH or allele imbalance in the initial biopsy and the number of genetic abnormalities increased in the tumours that developed. This type of molecular profiling may help to identify patients with lesions that may recur or acquire additional genetic events and progress to malignancy.

Adult↗
PubMed1996

LOH at 3p correlates with a poor survival in oral squamous cell carcinoma.

We analysed chromosome 3p for loss of heterozygosity (LOH) in 48 primary oral squamous cell carcinomas (SCCs) using 15 markers and constructed a deletion map for this chromosome arm. LOH at one or more loci was found in 34/48 (71%) of tumours. The data support the existence of at least three distinct regions of deletion at 3p24-26, 3p21.3-22.1 and 3p12.1-14.2. A significant correlation was observed between the number of regions showing allele loss at 3p and tumour stage, consistent with the progressive accumulation of genetic errors during the development of oral SCC. There were also significant associations between LOH at 3p and disease-free and overall survival of patients with early stage disease. This study is the first to demonstrate the prognostic significance of LOH at 3p for oral cancer and may help to identify patients who should receive more aggressive treatment.

Adult↗
PubMed1995

Craniofacial growth in bilateral cleft lip and palate patients following secondary premaxillary setback.

Data of an experimental group of bilateral cleft lip and palate patients (BCLP) who had undergone premaxillary setback at a mean age of 10.2 years were compared with a control group of standard cephalometric values for the white population, and with cephalometric data of BCLP patients from the Oslo Cleft Lip and Palate Archive who did not have premaxillary setback. Cephalometric lateral skull radiographs were taken at a mean age of 16.6 years when most facial growth is completed. Overall, the most marked difference between the two cleft samples was a slightly more concave profile in the experimental BCLP group, mainly due to clockwise rotation of the maxillary plane. Other differences were a longer face and a larger mandible in the experimental group.

Adolescent↗
PubMed1995

Management of oral cancer.

Oral cancer is a serious disease that is on the increase. The most pressing need is early recognition and referral for specialist treatment. Too many cases present with advanced tumours. Radiotherapy and surgery remain the primary modalities of curative treatment, but understanding of tumour pathology and developments in surgical and radiotherapeutic technique have combined to produce a rational approach to management. In many instances 'radical' methods of surgical access can be combined with a more 'conservative' resection of the mandible or cervical lymph nodes. One-stage reconstructive procedures, often incorporating osteotomy techniques, miniature bone plating and free tissue transfer, have minimised the morbidity and functional deficit so often seen after earlier operations. All surgeons involved in the modern management of oral cancer should have expertise in these techniques or be part of a team which can provide them.

Humans↗
PubMed1994

Frequent deletion of chromosome 3p in oral squamous cell carcinoma.

Evidence suggests that the accumulation of genetic lesions in dominant oncogenes and tumour suppressor genes is involved in the development of human cancers. We have used restriction fragment length polymorphism analysis to identify chromosomal deletions which may indicate the location of potential tumour suppressor genes. Deletion of chromosome 3p was found in 17/21 (81%) of informative primary oral squamous cell carcinoma (SCC) using a polymorphic probe recognising the D3F15S2 locus (3p21). Loss of heterozygosity (LOH) was not confined to patients exposed to recognised risk factors such as heavy smoking or alcohol consumption and was present at an early stage in the disease suggesting that this genetic alteration may be a fundamental event for oral cancer.

Adult↗
PubMed1994

Repair of the radial forearm flap donor site with a full-thickness graft.

A method of closing the radial forearm free flap donor site defect with a defatted, full-thickness skin graft is described. Its advantages of improved patient mobilization, protection of tendons, and cosmesis are discussed with reference to 16 consecutive patients treated over a period of 1 year.

Abdomen↗
PubMed1992

Expression of the tumour suppressor gene p53 in oral cancer.

In this preliminary series, the product of the tumour suppressor gene p53 was detected in 12/15 cases of oral squamous cell carcinoma (SCC) and in two cases of leukoplakia. The tumours either expressed the mutant form of p53 throughout the specimen or contained focal areas of positive cells. p53 expression was commonly observed in tumours obtained from patients who were heavy smokers and drinkers suggesting that alterations in the p53 gene may be one of the sites of genetic damage in this group of patients.

Alcohol Drinking↗
PubMed1992

Infantile fibromatosis with involvement of the mandible.

Two unusual cases of infantile fibromatosis involving the mandible occurring in 2-year-old children are described. These tumours, though initially highly aggressive, underwent spontaneous regression in the absence of definitive treatment.

Cell Nucleus↗
PubMed1991

A simple method for fixation of post-condylar cartilage grafts.

The use of the post-condylar cartilage graft for the treatment of retrognathia in adolescent patients has in the past been complicated by spontaneous displacement of the graft. Although a reliable method of fixation has evolved, the technique is not simple. The method described here is simple and provides secure immobilisation of the graft in the post-condylar space. A prospective study is needed to evaluate the long term success of this technique.

Bone Screws↗