Interpretation and management of oral symptoms experienced by scuba divers.
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Arthralgia↗
Biomedical subjects
W F van Heerden
Publications and source records attributed to W F van Heerden.
Immunohistochemical evaluation of Fhit protein expression in oral squamous cell carcinomas.
The expression of Fhit (fragile histidine triad) protein in oral squamous cell carcinoma (OSCC) and adjacent oral epithelium was evaluated by immunohistochemistry on formalin-fixed paraffin-embedded blocks of 32 cases of OSCC. Rabbit polyclonal anti-GST-Fhit antiserum at 1:600 was used, after antigen enhancement in a microwave pressure cooker, in a saturated lead thiocyanate solution. This antiserum has been shown specifically to detect human Fhit by immunohistochemistry at dilutions up to 1:10,000. The Fhit protein expression was evaluated using both the intensity and extent of staining. Normal stratified squamous epithelium showed strong positivity, especially in the stratum spinosum and areas of keratinisation. Basal and parabasal cells were negative or expressed low levels of Fhit relative to the squamous epithelium. Mild and moderate epithelial dysplasia showed Fhit expression in the superficial layers, while Fhit expression was absent from severely dysplastic lesions. A reduction or loss of Fhit expression was found in 21 (66%) of the OSCC. The alterations in Fhit protein expression in OSCC, and not in normal tissues, are consistent with the proposal that Fhit inactivation plays a role in oral carcinogenesis.
Acid Anhydride Hydrolases↗
Detection of p53 gene mutations in oral squamous cell carcinomas of a black African population sample.
Mutations in the p53 gene have been reported in head and neck carcinomas. We determined the p53 mutation profile in 55 oral squamous cell carcinomas (OSCCs) from a black African population sample. DNA from all the patients were investigated using PCR amplification of the p53 gene (exons 5-9), followed by heteroduplex single-stranded conformational polymorphism (HEX-SSCP) analysis on the PCR products. Direct sequencing was performed on cases where mutations were identified. The results showed mutations in 13 of 55 (23.6%) tumours. Eleven of 13 (85%) were single base pair substitutions (9 transitions and 2 transversions), and 2 were deletions. Two novel mutations were identified: a large 63-base pair deletion, and a single base pair substitution. The mutations in our study occurred outside the head and neck tumour hot spot region (codons 238-248).
Adult↗
High-resolution DNA flow cytometry in papillary cystadenoma lymphomatosum (Warthin's tumour).
Twenty-eight examples of papillary cystadenoma lymphomatosum (Warthin's tumour) of the parotid gland were analysed by high-resolution DNA flow cytometry. The mean coefficient of variation was found to be 1.19% (SD: 0.41). All tumours were DNA diploid. These results did not correspond with expected deviations based on published chromosomal studies. Also, the homogeneously low S-phase fractions (mean: 4.8%; SD: 2.7) found did not support the hypothesis of etiologically distinctive subgroups in these tumours.
Adenolymphoma↗
Creutzfeldt-Jacob disease: how does it affect dentistry?
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Bone Transplantation↗
Morphology of the deciduous tusk (tush) of the African elephant (Loxodonta africana).
The tusk of the African elephant is preceded by a deciduous tooth generally known as the tush. Tushes from nine elephant fetuses and six calves younger than 1 year were exposed by dissection and described morphologically. All tushes consisted of a crown, root and pulpal cavity, the formation of which is completed soon after birth. They reached a maximum length of 5 cm, appeared not to erupt through the skin and were pushed aside and resorbed during enlargement of the distally located primordium of the tusk. Dental enamel, which covered the crown, could easily be removed and consisted of rods with an interwoven arrangement; the dentine-enamel junction was flat. Cellular cementum extended for variable distances over the crown and the dentine was tubular in nature. Although the tush apparently has no function, it provides the anlage and orientation for the development of its permanent successor.
Animals↗
Lack of correlation between DNA ploidy, Langerhans cell population and grading in oral squamous cell carcinoma.
This study was undertaken to determine the inter-observer reproducibility of the invasive cell grading method on oral squamous cell carcinomas and to correlate this with the DNA ploidy status and Langerhans cell (LC) population. Fifty formalin-fixed paraffin-embedded blocks that contained both tumor and adjacent normal epithelium were randomly selected. DNA ploidy analysis was performed on a flow cytometer and the LC population was determined using an immunohistochemical technique with anti-S100 and anti-HLADR primary antibodies. The inter-observer correlation of the total malignancy score and individual morphologic features was highly significant. Thirty-two of the 50 tumors were graded as poorly differentiated and 18/50 as moderately differentiated. Thirteen of 25 poorly differentiated tumors had an aneuploid DNA content compared with 9/18 of the moderately differentiated group. No statistical differences in the LC counts between the poorly and moderately differentiated and aneuploid and diploid carcinomas were found. This study showed that the invasive cell grading method is reproducible but no correlation was found between the grading results and the ploidy status or LC count.
Aneuploidy↗
Infrequent clinicopathological findings in 108 ameloblastomas.
One hundred and eight ameloblastomas diagnosed in a rural black Africa population were analysed for clinicopathologic findings other than those classically described. One patient had a polycystic ameloblastoma adjacent to an ameloblastic fibroma. Two other polycystic ameloblastomas showed aneurysmal bone cyst formation and one mandibular tumour was diagnosed as a keratoameloblastoma. Microscopic changes resembling an adenomatoid odontogenic tumour were present in association with two unicystic ameloblastomas and a HPV18-positive verrucous lesion occurred in the lining of a cystic space of a polycystic ameloblastoma. Two ameloblastomas contained eosinophilic granules in all tumor cells and melanocytes were diffusely present in another. One case exhibited a focus of mucous cell metaplasia. Two polycystic ameloblastomas showed diffuse interstitial ossification. One mandibular tumor was diagnosed as a desmoplastic ameloblastoma and another as an odontoameloblastoma. This study demonstrated that although ameloblastomas are regarded as a fairly homogeneous group of neoplasms, detailed investigations prove clinicopathologic diversity in a significant number of lesions.
Adolescent↗
Detection of human papillomavirus DNA with in situ hybridisation in oral squamous carcinoma in a rural black population.
Intra-oral carcinoma is the third most common malignancy among men in developing countries, and carries a high mortality rate, particularly in Africa, where patients often present initially with lesions at an advanced stage. The present study was undertaken to determine the prevalence of human papillomavirus (HPV) DNA in oral squamous carcinoma in the west of the Northern Transvaal, an area where a large number of new cases has been diagnosed over the past few years. Paraffin blocks from 66 cases (51 men, 15 women; mean age 58.7 years) of oral squamous carcinoma were randomly selected. Blocks contained samples of both tumour and adjacent normal epithelium. The presence of HPV antigen was established by means of immunocytochemistry and HPV DNA by in situ hybridisation with radiolabelled probes for HPV-6, 11, 16 and 18. Immunocytochemistry for viral antigen was negative in all the specimens. HPV-18 was detected in normal epithelium adjacent to the tumour in one case only. It appears from our study that HPV is of limited importance in oral squamous cell carcinogenesis in the population studied.
Black or African American↗
The use of tricure glass ionomer cement as an apical sealant after apicoectomy.
The adaptation and sealing ability of a tricure glass ionomer material (Vitremer), used in a retrograde cavity was assessed and compared with amalgam. Fifty single-rooted, extracted teeth were prepared and filled endodontically. All teeth underwent root resection and retrograde cavities were prepared. The teeth were divided into two groups. One group of 10 teeth received a layer of varnish and an amalgam filling in a retrograde cavity, while the other group of 40 teeth received a layer of primer and a glass ionomer filling. All the teeth were placed in an aqueous solution of Procion Brilliant Blue for 7 days whereafter ground sections were prepared. Micro leakage was determined according to the extend of dye penetration using an image analysis system. The results showed that significantly less dye penetration was observed in teeth filled with the glass ionomer cement than in those with the amalgam.
Apicoectomy↗
Exploring the applications of the Internet: a guide for the first time user.
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Computer Communication Networks↗
Oral yeast flora of a Kalahari population.
During an epidemiological survey of 181 individuals working or residing in the Kalahari National Gemsbok Park, swabs were taken from the dorsal surfaces of their tongues to determine a possible association between oral yeasts and clinically observed oral lesions as well as other underlying conditions detectable by serum chemistry. Identification of yeasts was performed with a commercially available identification system, namely the ATB 32C (Montalieu, Vercieu). Yeasts were isolated from 30.4 per cent (n = 55) of individuals, of whom 43.6 per cent (n = 24) had only Candida albicans, 3.6 per cent (n = 2) had C. albicans together with other yeasts and 52.7 per cent (n = 29) had other yeasts. Many of these yeasts were not the commonly encountered clinical isolates. The results revealed a significant association (p < 0.02) between yeasts (n = 55) and low serum iron concentrations (n = 50). A highly significant (p < 0.001) association was also found between smoking (n = 112) and the presence of clinically detectable oral lesions, notably leukoplakia (n = 21) and mucosal atrophy. The findings of this study reveal that a significant association exists between the oral yeast flora and serum iron and glucose, as well as between smoking and oral mucosal lesions.
Adolescent↗
Clinico-pathological study of 30 unicystic ameloblastomas.
The clinico-pathological records of 30 unicystic ameloblastomas collected over a period of 10 years were studied. The mean age at diagnosis was 18.0 years (SD +/- 8.1), most lesions were located in the mandible and were frequently associated with impacted teeth, root resorption and tooth displacement. The unicystic ameloblastomas in 11 patients (4 females and 7 males) exhibited invasion of the fibrous wall, 4 cases (1 female and 3 males) showed intra-luminal proliferation and the remaining 15 specimens (9 females and 6 males) were lined by non-proliferating ameloblastic epithelium. Two cases recurred 3 and 7 years after initial surgical removal. This study reveals the potential aggressive behaviour of unicystic ameloblastomas and underlines the importance of a thorough microscopic examination for sub-classification.
Adolescent↗
A retrospective analysis of 367 cystic lesions of the jaw--the Ulm experience.
Out of 846 cyst-like lesions of the jaws, 367 cases were retrieved from the files of the Department of Oral and Maxillofacial Surgery at the University of Ulm and classified according to the new World Health Organization's classification for odontogenic tumours and cysts. Radicular and residual cysts comprised 56.9%, dentigerous cysts 21.3%, odontogenic keratocysts 10.6%, unicystic ameloblastomas 4.1%, nasopalatine duct cysts 2.7%, glandular odontogenic cysts 1.6% and paradental cysts, traumatic bone cysts, calcifying odontogenic cyst and lateral periodontal cyst each less than 1% of the sample. Nearly one third of the specimens were obtained from military patients; despite an expected bias towards young males, unicystic ameloblastomas presented one and a half decades later than is generally reported.
Adolescent↗
Detection of human papillomavirus DNA in an ameloblastoma using the in situ hybridization technique.
HPV type 18 DNA was identified in an intrabony ameloblastoma using radiolabelled in situ hybridization. The viral DNA was found in a verrucous lesion in a cystic area of the tumor. The absence of HPV DNA in other epithelial areas of the ameloblastoma is suggestive of a secondary infection. HPV is not considered to be an etiological factor in the pathogenesis of this ameloblastoma.
Adult↗
Amino acid composition of dentine in permanent human teeth.
Dentine of permanent mandibular incisors from nine individuals was hydrolysed and the amino acid composition determined by ion-exchange chromatography against a standard calibrant of 41 amino acids. Nineteen amino acids were detected, including small quantities of 1-methylhistidine and asparagine, two amino acids whose existence had apparently not been recorded before in human dentine. The total content of hydroxylysine plus lysine varied between 2.6 and 3.3 residues per 100 (SD, 0.74) in different teeth, which therefore did not support previous studies that had proposed a constant total value. This and other quantifiable differences between present and previous findings may be the result of the different methods and the influence of dietary and other regional factors on dentinogenesis.
Amino Acids↗
Diffuse peripheral odontogenic fibroma: report of 3 cases.
Since peripheral odontogenic fibroma (POF) is characteristically described as a solitary lesion and no diffuse POF had been reported in the literature, our cases should be considered as extremely unusual. Three diffuse cases of POF are described of which one case was seen in association with ocular and skin lesions. The question arises whether POF should be considered as a true odontogenic tumor rather than a diffuse hamartomatous lesion caused by uncontrolled induction of the gingiva. It is also possible that such lesions could be part of a yet undescribed syndrome.
Child↗
Peripheral dentinogenic ghost cell tumor.
A case of dentinogenic ghost cell tumor, that has originated peripherally in the jaw, is presented and the literature reviewed with particular reference to the origin of the tumor. The total number of central and peripheral cases reported in the English literature is 10 and although mucosal infiltration is common, peripheral origin of the neoplasm could be verified in only 3 cases.
Aged↗