Biomedical subjects

E J Raubenheimer

Publications and source records attributed to E J Raubenheimer.

At least 19 recordsLinked to original sources

PubMed2006

Pathogenesis of bone metastasis: a review.

BACKGROUND: Metastasic deposits from malignancies frequently lodge in the skeleton, including the jaw bones. METHOD: A review of the literature was performed in order to provide a coherent overview on the pathogenesis of bone metastasis. RESULTS: Bone metastasis follows complex molecular interactions that enable tumor cells to detach from the primary site, invade the extracellular matrix, intra-vasate, extra-vasate, and proliferate within bone. They induce local bone changes that could manifest radiologically as either osteolytic or radiodense. In addition to the direct bone changes, malignancies can elaborate mediators that are released in circulation, leading to generalized osteopenia. CONCLUSIONS: The spread of malignant neoplasms to bone is not a random process but rather a cascade of specific molecular events orchestrated through complex interactions between neoplastic cells and their environment.

Bone Neoplasms↗

PubMed2006

Necrotizing gingivitis of Kaposi sarcoma affected gingivae.

Necrotizing gingivitis and oral Kaposi sarcoma are common concomitants of HIV infection and both are regarded as indicators of HIV infection. Their simultaneous appearance in an HIV seropositive subject therefore, should be relatively common; but other reports documenting such cases could not be found. This article documents an uncommon case of necrotizing gingivitis superimposed on Kaposi sarcoma-affected gingiva, occurring in a patient with chronic periodontitis. The nature of necrotizing gingivitis and Kaposi sarcoma and the possible differential diagnosis of the periodontal attachment loss are discussed.

AIDS-Related Opportunistic Infections↗

PubMed2005

The role of ivory in the survival of the African elephant.

The unique chequered pattern of polished ivory has created a perverted commercial demand for elephant tusks. The morphologic basis of the pattern, which makes ivory a sought after product for the manufacturing of works of art, is discussed. Chemical analyses of ivory holds great potential in tracing the source of illegally harvested tusks and exposing poorly managed elephant sanctuaries. The impact of uncontrolled ivory hunting on the population genetics of the African elephant is briefly reviewed.

Africa↗

PubMed2002

The glandular odontogenic cyst: clinical and radiological features; review of the literature and report of nine cases.

Nine cases with glandular odontogenic cysts (GOC's) are presented bringing the total number reported in the literature to 54. Our study confirmed that most GOC's occur in the mandible, whereas maxillary lesions present only in the globulo-maxillary region. The radiological features were found to be non-distinctive and presented as well-defined radiolucencies with uni- and multilocular appearances. Most of the mandibular GOC's were unilocular, involved the symphysis region and only one extended into the ramus. All GOC's larger than 6 cm in diameter showed perforated margins radiologically. Our two multilocular GOC's demonstrated microscopic features supporting their infiltrative radiological appearance. The invasive clinical and radiological features of GOC support the notion of a possible histo-pathologic overlap between GOC and low-grade central mucoepidermoid carcinoma of the jaw.

Adolescent↗

PubMed2000

Early development of the tush and the tusk of the African elephant (Loxodonta africana).

This early development was studied from a serial histological sections of eight elephant embryos with masses varying between 1 and 240 g. The tush and the tusk develop from one tooth germ in a deciduous to permanent tooth relation. In order to study the mineralization of the dental organ of the tush and cap and bell stage of the tusk, embryos older than 3-months' gestation (weighing more than 250 g) would be required.

Animals↗

PubMed2000

Maxillofacial hydatid cysts.

We report 2 cases of hydatid cysts occurring in the submandibular gland and buccal submucosa, respectively. Our first case occurred in the submandibular salivary gland of a 20-year-old woman and the second involved the buccal submucosa of a 6-year-old boy. Both diagnoses were made after the excision of the lesions. Both patients were evaluated after surgery, and both were followed up, but no other organs were involved.

Adult↗

PubMed2000

Calcifying epithelial odontogenic tumor with intracranial extension: report of a case and review of the literature.

The calcifying epithelial odontogenic tumor (CEOT) is a rare benign neoplasm, possibly of stratum intermedium origin and occurring predominantly in the mandible of adults. The treatment varies, depending on its size, location, and histology. A case of an advanced CEOT arising in the maxilla with intracranial extension is reported. The report is supplemented by a review of the literature.

Blindness↗

PubMed1998

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↗

PubMed1998

Geographic variations in the composition of ivory of the African elephant (Loxodonta africana).

Tracing the source of origin of illegal ivory will contribute to the identification of poorly managed game parks and facilitate steps taken to prevent the African elephant from becoming extinct. This study was aimed at establishing a database on the composition of ivory obtained from elephant sanctuary areas in Southern Africa. Fragments of elephant ivory from seven geographically distinct areas in South Africa, Namibia and Botswana were analysed for inorganic and organic content. A total of 20 elements was detected in the inorganic fraction of ivory, some in concentrations as low as 0.25 microg/g. The concentrations of calcium, phosphate, magnesium, fluoride, cobalt and zinc showed statistically significant differences (p < 0.007) between ivory obtained from different regions. Analyses of the organic fraction identified 17 amino acids. Ivory from arid regions showed significantly lower proline plus hydroxyproline content and under-hydroxylation of lysine residues. This study indicates that chemical analyses of ivory could be beneficial in tracing the source of illegal ivory.

Africa, Southern↗

PubMed1998

Histogenesis of the chequered pattern of ivory of the African elephant (Loxodonta africana).

This study aimed to propose a hypothesis on the events which lead to the development of the characteristic chequered pattern of elephant ivory. Twenty fragments of ivory and six elephant tusks were obtained through the National Parks Board of South Africa. Polished surfaces were prepared in sagittal and longitudinal planes and the characteristics of the distinctive chequered pattern described. Light- and electron-microscopical techniques and image analyses were employed to determine the morphological basis of the pattern and to describe the spatial distribution, density and morphology of the dentinal tubules. These investigations showed that the distinctive pattern was the result of the sinusoidal, centripetal course followed by dentinal tubules. The apical, slanted part of the sinusoidal curve is the result of the centripetally moving odontoblast, which, during formation of ivory, progresses towards the centre of the tusk on a decreasing circumference. It is suggested that this leads to cell crowding, increased pressure between odontoblasts and subsequent apical movement of their cell bodies, cell degeneration and fusion. Odontoblastic degeneration and fusion probably relieve the pressure between the crowded odontoblasts by reducing their numbers and the remaining odontoblasts now orientate their centripetal course towards the tip of the tusk, thereby forming the anterior-directed part of the sinusoidal path of the tubule. As odontoblasts progress centripetally the diameter of the pulpal cavity decreases further and the processes of apical movement, fusion and degeneration of odontoblasts are repeated. This occurs until the pulpal cavity is obliterated.

Anatomy, Cross-Sectional↗

PubMed1998

Low-grade intraosseous osteosarcoma of the jaws.

Two cases of low-grade intraosseous osteosarcomas are reported, bringing the total number of such osteosarcomas in the jawbones documented in recent literature to six. Our first case involved the maxilla of a 69-year-old man and the second involved the mandible of an 18-year-old girl. In clinical and microscopic appearance, these neoplasms resemble benign proliferations in many respects. Subtle differences include cortical bone destruction, soft tissue infiltration, irregular bone production with foci of abundant osteoid, and mild cellular atypia. Complete removal at the first attempt is of paramount importance, inasmuch as a significant percentage of these neoplasms recur as high-grade osteosarcomas if they are inadequately treated.

Adolescent↗

PubMed1998

Gigantiform melanotic neuroectodermal tumor of infancy.

Melanotic neuroectodermal tumor of infancy is a rare neoplasm of possibly neural crest origin, and it predominantly occurs in the premaxillas of infants less than 12 months old. Generally, the treatment of this benign pigmented lesion is conservative surgical excision. Long-term follow-up is imperative inasmuch as local recurrence and malignant transformation have been reported. A case with exceptional clinical features involving a 7-month-old child is presented.

Female↗

PubMed1997

Static and dynamic bone changes in hospitalized patients suffering from rickets--a histomorphometric study.

AIMS: The aim of this study was to assess static and dynamic bone changes in patients suffering from rickets. METHODS AND RESULTS: Transcortical iliac crest biopsies of 15 hospitalized children with rickets were taken after labelling new bone formation with two cycles of tetracycline administration 10 days apart. Undecalcified sections were prepared, appropriately stained and histomorphometric analysis performed. Static and dynamic bone changes were measured including the volume of bone and osteoid, trabecular and cortical bone dimensions and resorptive and mineralization activities. The results were compared with normal values. The nature of the mineralization fronts was noted. Trabecular osteoid volumes of all but one patient was above the normal range of 1.9% (+/-0.4%). This patient suffered rickets associated with the Kwashiorkor-Marasmus syndrome. Tetracycline labelling was found to be more sensitive than subjective evaluation of the nature of the mineralization fronts. Despite a balanced hospital diet, a bone formation rate of zero was found in three cases, indicating a need for vitamin D and mineral supplementation. Seven cases had decreased mineralization lag times, indicating response to the balanced diet. CONCLUSIONS: This study showed that histometric analysis of labelled bone biopsies is a helpful adjunct to the diagnosis but particularly assessment of response to management of deficiency states in children.

Adolescent↗

PubMed1995

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↗

PubMed1995

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↗

PubMed1995

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↗

PubMed1995

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↗

PubMed1994

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↗