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Biomedical subjects

W F van Heerden

Publications and source records attributed to W F van Heerden.

13 recordsLinked to original sources
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1991

Intraoral salivary gland neoplasms: a retrospective study of seventy cases in an African population.

Intraoral salivary gland neoplasms diagnosed in the Department of Oral Pathology, Medical University of Southern Africa, Medunsa, were reassessed and revised with regard to histologic diagnosis. New entities and subclassifications that have been described in recent years were taken into account. Seventy cases were diagnosed during an 8-year period, and the sample consisted of black patients only. Benign mixed tumor was the most common entity and accounted for 48% of all tumors. Polymorphous low-grade adenocarcinoma comprised 15.7% of the sample and was the most frequent malignant tumor. The mean age of patients with benign and malignant tumors were 36.5 and 49.8 years, respectively (p less than 0.05), and the palate was the most common site involved. Geographic differences do exist in the pattern and pathology of intraoral salivary gland neoplasms when compared with findings in other studies.

Adenocarcinoma↗
PubMed1991

Evaluation of the nucleolar organizer region associated proteins in minor salivary gland tumors.

Forty-three intraoral salivary gland tumors were studied to determine the value of the AgNOR technique in the assessment of these neoplasms. Well defined black dots were visible in the nucleii of all the specimens studied. The mean AgNOR count per nucleus for each tumor was calculated as follows: pleomorphic adenoma (n = 15) 1.52; Polymorphous low-grade adenocarcinoma (n = 12) 1.90; adenoid cystic carcinoma (n = 6) 2.92; mucoepidermoid carcinoma (n = 4) 1.93; carcinoma ex mixed tumor (n = 4) 2.05; undifferentiated carcinoma (n = 1) 3.13 and epithelial-myoepithelial carcinoma (n = 1) 2.23. The difference between the means of benign and malignant tumors (P less than 0.01) and polymorphous low-grade adenocarcinoma and adenoid cystic carcinoma (P less than 0.01) were highly significant. The overlapping of the AgNOR count between various tumors prohibited the use of this technique as an absolute criterion in establishing a final diagnosis. It could however be used as a diagnostic aid in differentiating between salivary gland neoplasms.

Adenocarcinoma↗
PubMed1991

Adenomatoid odontogenic tumour: a report of two large lesions.

Adenomatoid odontogenic tumours with a diameter of more than 4 cm are uncommon. Two cases, both measuring in excess of 7 cm, are described and the differential diagnosis discussed. The progressive growth and cortical perforation in these two cases support the view that it is a benign neoplasm rather than a hamartoma.

Child↗
PubMed1990

Amelogenesis imperfecta: multiple impactions associated with odontogenic fibromas (WHO) type.

Three types of amelogenesis imperfecta (AI) are recognised, namely hypoplastic, hypomature and hypocalcified varieties. We report on two cases of hypoplastic AI, the type which occurs most frequently. Both patients presented with multiple impacted permanent teeth. Odontogenic fibromas of the WHO type were found to be associated with the crowns of all the impacted teeth and are considered to have prevented normal eruption. Dentinal dysplasia found only in the furcation area of the multirooted impacted teeth was evident. The macroscopic, microscopic and radiological appearance of the affected teeth, pericoronal lesions and interradicular dentinal dysplasia are described, and the most likely origins of the odontogenic fibromas and calcifications observed, are discussed.

Adolescent↗
PubMed1989

Giant ossifying fibroma: a clinicopathologic study of 8 tumors.

Clinical, radiographic and microscopic features of 8 ossifying fibromas diagnosed in 7 patients and measuring more than 8 cm in greatest diameter, were reviewed. The tumors occurred in both juvenile and middle aged patients and all lesions in women involved the maxilla. The abundance of fibrous connective tissue and resorption of mineralized deposits are indicative of altered cellular differentiation and proliferative activities in large ossifying fibromas. Focal areas of aneurysmal bone cyst formation were identified in the majority of lesions.

Adolescent↗
PubMed1989

Diagnosis of oral precancer and cancer.

The early diagnosis of oral cancer and precancer is important because oral cancer is usually well advanced at the time of diagnosis, having spread to regional lymph nodes in a substantial percentage of cases. The earlier the diagnosis is made, the better the prognosis. Several diagnostic methods that are used, such as stomatoscopy, toluidine blue staining, oral exfoliative cytology, histopathological examination and other more advanced diagnostic procedures, are discussed.

Adult↗
PubMed1989

Odontoma in an African elephant (Loxodonta africana).

The first known case of an odontoma in an African elephant (Loxodonta africana) is described. The tumour was fused with the coronal cementum of the sixth right mandibular molar tooth, thus preventing its eruption.

Animals↗
PubMedDate not supplied

Glandular odontogenic cyst.

Two cases of glandular odontogenic cysts are reported. The unique histological features, eg, the intraepithelial glandular structure, papillary processes, and eosinophilic cuboidal and larger granular superficial cells are sufficient to warrant glandular odontogenic cyst as a distinct entity. Electron microscopic examination of the superficial eosinophilic cuboidal cells are suggestive of a process similar to apoptosis. Eroded cortical plates suggest an aggressive behavior.

Adolescent↗