Biomedical subjects

M Altini

Publications and source records attributed to M Altini.

At least 19 recordsLinked to original sources

PubMed2001

The spatial and temporal expression of calretinin in developing rat molars (Rattus norvegicus).

Calretinin is a 29-kDa calcium-binding protein abundantly expressed in central and peripheral neural tissues. The aim here was to determine its expression during various stages of odontogenesis. Five categories of embryonic (E) and postnatal (P) rats at various ages (E17, E18, E20, P0, and P7), both male and female, were used to represent the various stages of molar tooth development. The heads of the experimental animals were harvested at the appropriate time and each was cut mid-sagittally and coronally to locate the tooth germs. Selected sections were stained immunohistochemically with polyclonal rabbit anticalretinin at a concentration of 1:25 after microwave irradiation. The results showed that calretinin is distributed widely in epithelium-derived tissues during odontogenesis in rat molar tooth germs. It was expressed focally in the dental lamina, outer enamel epithelium, stellate reticulum and stratum intermedium at different stages. In contrast, it was expressed diffusely and intensely in the inner enamel epithelium and presecretory ameloblasts, although it was discontinuous over the cusp tips. In the secretory ameloblasts, the staining was less intense, being restricted to the cytoplasm, including Tomes' processes. This distribution suggests that calretinin may play a part in enamel formation.

Age Factors↗

PubMed2001

Use of calretinin in the differential diagnosis of unicystic ameloblastomas.

AIMS: Calretinin, a 29-kDa calcium-binding protein is expressed widely in normal human tissues and tumours including both unicystic and solid and multicystic ameloblastomas. The histological distinction between unicystic ameloblastomas and certain non-neoplastic odontogenic cysts can be problematic. The objective of this study was to determine whether calretinin was expressed in the lining epithelium of odontogenic keratocysts, residual and dentigerous cysts and to determine whether this calcium-binding protein could be used to distinguish these cysts from the unicystic ameloblastoma. METHODS AND RESULTS: The lining epithelium in 22 cases of odontogenic keratocyst, 26 cases of residual cyst and 20 cases of dentigerous cyst were examined for the expression of calretinin. No positive epithelial staining was observed in any of these cystic lesions. In comparison, however, 81.5% of cases of unicystic ameloblastoma showed a coarse dark brown staining of the more superficial epithelial cell layers. Scattered positive stromal and epithelial cells were present; these were interpreted as mast cells. CONCLUSIONS: Calretinin appears to be a specific immunohistochemical marker for neoplastic ameloblastic epithelium and we suggest that it may be an important diagnostic aid in the differential diagnosis of cystic odontogenic lesions and ameloblastic tumours.

Ameloblastoma↗

PubMed2001

Clear cell odontogenic carcinoma. Report of two cases and review of the literature.

This study reviews the literature and reports on the morphologic and immunophenotypic features of 2 clear cell odontogenic carcinomas occurring in the mandible of elderly women, showing extensive infiltration into adjacent tissues. The tumor cells were large, with clear cytoplasm, and arranged in irregular sheets. Some of the latter demonstrated a peripheral rim of cells with eosinophilic cytoplasm or included duct-like structures. There was no evidence of ameloblastic differentiation. Most cells contained glycogen granules and were immunoreactive for cytokeratins and epithelial membrane antigen. In the differential diagnosis other clear cell odontogenic, salivary gland, and metastatic tumors should be considered. Both cases were treated with surgical excision, and the patients are free of disease after 3 and 5 years, respectively. In the literature, however, variable behavior of these tumors has been reported, including recurrence and metastases. It is recommended that terms such as clear cell ameloblastoma and clear cell odontogenic tumor not be used to describe such tumors.

Aged↗

PubMed2000

Cellular heterogeneity of granular cell tumours: a clue to their nature?

Most granular cell tumours (GCTs) are benign proliferations of purported Schwannian derivation, showing immunoreactivity for Schwann cell-related antigens. Due to incomplete agreement on the precise nature of GCTs (reactive vs neoplastic), we performed an immunohistochemical study with the alkaline phosphatase/anti-alkaline phosphatase (APAAP) technique on 30 GCTs. The aim was to evaluate their growth patterns and the possible relationships of granular cells with other nerve sheath-related cell types (i.e., Schwann and perineurial cells, and dendritic cells displaying CD34/vimentin immunoreactivity). An expansive growth pattern was detected in five cases, a pseudoinfiltrative growth pattern in nine cases and a mixture of the above in the remaining 16 cases. Besides immunoreactivity for S-100 protein, neuron-specific enolase, vimentin, CD57, CD68, MAC 387, alpha-1-antitrypsin and alpha-1-antichymotrypsin in granular cells, we documented intimate architectural relationships between granular cells, Schwann and perineurial cells, and a third type of CD34/vimentin-positive nerve sheath-related cell in most GCTs. These results suggest that GCTs are heterogeneous lesions. Some of them show a pseudoinfiltrative growth pattern and retain close relationships with the normal components of the nerve sheath. In other lesions, granular cells grow in an expansive fashion and constitute the predominant cell component of the tumour. These architectural and immunophenotypic differences may reflect a different nature of GCTs: they may initially represent reactive or hamartomatous lesions that subsequently acquire truly neoplastic potential.

Adult↗

PubMed2000

Calretinin expression in ameloblastomas.

AIMS: Calretinin is a 29-kDa calcium-binding protein which is expressed in the central and peripheral nervous systems as well as in many other normal and pathological human tissues. The objective of this study was to determine whether calretinin was expressed in the epithelium of ameloblastomas. METHODS AND RESULTS: Twenty-seven cases of unicystic ameloblastoma and 31 cases of solid and multicystic ameloblastoma were studied. Five-micron sections were immunohistochemically stained using either antiserum 7696 from Swant, or antiserum 18-0211 from Zymed with a standard ABC method. The results were identical with the two antisera. Positive staining was seen in 22 cases (81.5%) of unicystic ameloblastomas. This generally consisted of diffuse, intense nuclear and cytoplasmic staining of several cell layers of the more superficial cells both in the characteristic and nondescript areas of the cyst linings. In the solid and multicystic ameloblastomas, staining occurred in 29 (93. 5%) of the cases. The staining was almost always restricted to the stellate reticulum-like epithelium, was generally intense and diffuse in distribution. Areas of squamous metaplasia stained particularly intensely as did the cells surrounding micro- and macro-cysts. In both groups of lesions, most of the cases that did not stain were intensely inflamed. CONCLUSIONS: The biological significance of calretinin expression in ameloblastomas is not known and its use as a distinctive, specific immunohistochemical marker for ameloblastic tissues remains to be confirmed. However, the results of this study raise the possibility that calretinin may be an important diagnostic aid in the differential diagnosis of cystic and solid ameloblastic tumours.

Ameloblastoma↗

PubMed2000

Authors' reply

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Journal Article↗

PubMed1999

Cystic degeneration in fibrous dysplasia of the jaws: a case report.

A case of nonspecific cystic degeneration complicating fibrous dysplasia of the mandible is presented. This condition is extremely rare in the jaw bones. The patient had a painless swelling of the right face measuring 10 cm in diameter, and there was no history of trauma. Radiographs showed a poorly defined, "ground glass" radiopaque lesion; a central well-defined cyst was confirmed by means of computed tomography. During surgery, a large cystic cavity with surrounding, soft fibrous bone that merged with the cortex was observed. Histologic examination showed a large non-epithelial-lined cystic cavity with a surrounding fibro-osseous lesion, which was consistent with a diagnosis of fibrous dysplasia.

Child↗

PubMed1999

Intravascular tumour in intra-oral pleomorphic adenomas: a diagnostic and therapeutic dilemma.

AIMS: Intravascular tumour has been described very rarely in pleomorphic adenomas. The aim of this study was to establish the frequency of intravascular tumour in pleomorphic adenomas arising in minor salivary glands and to determine the biological significance of this phenomenon. METHODS AND RESULTS: Representative sections of 67 widely excised pleomorphic adenomas were examined for the presence of intravascular tumour. Sixty-two cases were derived from the palate while the remaining five were from the cheeks and lips. In instances where intravascular tumour was identified, multiple serial sections were assessed and immunohistochemical stains were performed. None of these cases showed cytological evidence of malignancy. Solid cords of intravascular tumour were present in six palatal tumours (8.9%) and consisted of plasmacytoid myoepithelial cells permeating muscular walled blood vessels and capillaries both within the tumour and capsule. Immunoperoxidase staining confirmed that the intravascular cells were phenotypically identical to those of the tumour being S100- and smooth muscle actin (SMA) positive. There is some evidence that this phenomenon represents true vascular invasion although artefactual spillage cannot be excluded. CONCLUSIONS: Although the biological significance of intravascular tumour in pleomorphic adenomas of minor salivary glands remains unknown, the occurrence of metastatic disease has not been demonstrated nor have aggressive behaviour or recurrences.

Actins↗

PubMed1998

Sialadenosis: a presenting sign in bulimia.

BACKGROUND: Sialadenosis refers to noninflammatory, often recurrent, enlargement of the salivary glands, most frequently the parotids, which is almost always associated with an underlying systemic disorder. These include diabetes, alcoholism, malnutrition, anorexia nervosa, and bulimia. It is thought that the various causes of sialadenosis all result in a common pathogenetic effect in that they produce a peripheral autonomic neuropathy which is responsible for disordered metabolism and secretion, resulting in acinar enlargement. METHODS: This paper reports a case of sialadenosis as a presenting sign in bulimia and studies the histologic and electron microscopic features of this disease. RESULTS: Light microscopy showed acini which appeared to be larger than normal and which were composed of plump pyramidal cells containing prominent zymogen granules. There was less interstitial fat, and the ducts were widely dispersed. Electron microscopy showed the acinar cells to be packed with membrane-limited, dark secretory granules some of which showed moulding of their outlines. Cellular organelles and nuclei were inconspicuous. CONCLUSIONS: Management of sialadenosis depends upon identification of the underlying cause, which must then be corrected. In bulimia, the swellings may be refractory to standard treatment modalities, and parotidectomy may be considered as a last resort to improve the unacceptable aesthetics.

Adult↗

PubMed1997

Intra-vascular tumour in pleomorphic adenomas--a report of four cases.

AIMS: The aim of this study was to report four cases of pleomorphic adenoma which were characterized by intra-vascular tumour. METHODS AND RESULTS: The patients ranged in age from 13-43 years, one was male while three were female. The tumours were situated in the parotid gland, submandibular gland and palate (two cases). The intra-vascular tumour consisted of single, clustered and solid cords of cells within multiple muscular walled blood vessels and capillaries both in the capsule and in the tumour. Immunoperoxidase staining confirmed that the intra-vascular cells were phenotypically identical to those of the tumour. The possibility that the intra-vascular tumour represents artefactual 'spillage' has been considered, however there is some histological evidence suggesting that this phenomenon represents true vascular invasion. CONCLUSIONS: The biological significance of intra-vascular tumour in pleomorphic adenomas is unknown. Thus far there has been no correlation with either recurrence or metastases.

Adenoma, Pleomorphic↗

PubMed1997

Clear cell tumors of the salivary glands, jaws, and oral mucosa.

Clear cell tumors of the oral mucosa, jaws, and salivary glands constitute a heterogeneous group of lesions which may be either odontogenic, salivary gland, or metastatic in origin. Clear cells in these proliferations most frequently result from fixation artifact but may also be the result of cytoplasmic accumulation of water, glycogen, intermediate filaments, or immature zymogen granules, or a paucity of cellular organelles. Odontogenic neoplasms that may be characterized by a predominantly clear cell component include odontogenic carcinoma, ameloblastoma, and calcifying epithelial odontogenic (Pindborg) tumor. Clear cell tumors of salivary gland origin are almost invariably malignant in nature but they do include two benign lesions; namely, oncocytoma and myoepithelioma. Clear cells in acinic cell carcinoma seldom comprise a significant portion of the tumor whereas clear cell mucoepidermoid carcinomas can readily be identified by an admixture of clear-squamoid, mucous and intermediate cells. Lesions previously reported as "clear cell adenoma" "clear cell carcinoma, or glycogen-rich carcinoma" can be divided into the distinctive biphasic epithelial-myoepithelial carcinoma and monophasic lesions which have been shown to be either myoepithelial or ductal in origin. The latter are primarily represented by the recently described "hyalinizing clear cell carcinoma." The most common metastatic clear cell tumor in the oral mucosa and the jaws is the renal cell carcinoma. However, metastases of melanoma and malignant clear cell tumors of the prostate, bowel, thyroid, and liver must also be considered.

Carcinoma↗

PubMed1996

Three-dimensional computed tomography reconstruction in treatment planning for large ameloblastoma.

A case of an unusually large mandibular ameloblastoma is reported in which standard radiologic examination failed to provide adequate visualization of the tumor's limits because of overlapping structures and the presence of compound shadows. Computed tomography imaging and three-dimensional reconstruction proved invaluable in the treatment planning of this large lesion, because it allowed the surgeon to visualize and comprehend the geography of the tumor and its relationship to surrounding structures and soft tissues and to formulate a surgical plan. Use of this technique helped ensure complete excision of the tumor without excessive removal of uninvolved tissue.

Ameloblastoma↗

PubMed1996

Neuroendocrine (carcinoid) tumor of the mandible: a case report and review of the literature.

The aim of this article is to present a case of primary neuroendocrine tumor (typical carcinoid) of the mandible that occurred in a 46-year-old black woman who was seropositive for the human immunodeficiency virus. Radiologically the lesion presented as a poorly circumscribed honeycomb radiolucency that extended from tooth 21 to the ascending ramus. Histologically the tumor cells were variously arranged in small islands, trabeculae, follicles, and slitlike spaces lined by a single layer of palisaded low-columnar cells. The follicles contained an eosinophilic colloid-like substance. Immunocytochemical staining showed diffuse, intense positivity for MAK 6, pancytokeratin, S-100, and neuron-specific enolase and focal, intense, positive staining for chromogranin A. Electron microscopy showed the presence of interdigitating cell membranes, rudimentary cell attachments, and varying numbers of membrane-bound dense core granules. Special investigations failed to reveal a primary tumor, and no metastases were found. Urine and hematologic assessment did not show any evidence of functional activity. The tumor was resected, and no recurrence or spread has been seen for 2 years. Origin from foregut-derived, immature, and functionally uncommitted endocrine cells is presumed.

Carcinoid Tumor↗

PubMed1996

Dentigerous cysts of inflammatory origin. A clinicopathologic study.

The exact histogenesis of dentigerous cysts remains unknown, but most authors favor a developmental origin from the tooth follicle. The aim of this article is to report a series of 15 dentigerous cysts that we believe to be of inflammatory origin. These inflammatory dentigerous cysts occurred in the first and early part of the second decades of life. Males were affected more frequently, and there did not appear to be any racial predilection. All of the cases involved permanent teeth: premolars in nine cases, canines in four cases, and second molars in two cases. The mandible was affected twice as frequently as the maxilla. In 13 cases, nonvital grossly carious or heavily restored deciduous teeth were associated with the cysts. Some of these teeth had been extracted before the cysts were diagnosed. In the remaining two cases, both of which involved the second permanent molars, there were no nonvital deciduous teeth, however both had concomitant proliferative periostitis. All of the cysts were moderately or intensely inflamed and were lined predominantly or entirely by nonkeratinized stratified squamous epithelium that in some cases was markedly hyperplastic and exhibited anastomosing rete ridges mimicking radicular cysts. In the majority of cases, parts of the cysts were lined with a 2 to 3 cell layer thick cuboidal epithelium that we believe was derived from reduced enamel epithelium. Rests of odontogenic epithelium frequently were evident in the cyst walls. We suggest that these cysts arose as a result of periapical inflammation from any source but usually from a nonvital deciduous tooth and spreading to involve the follicles of the unerupted permanent successors. The inflammatory exudate causes separation of the reduced enamel epithelium from the enamel with resultant cyst formation. This study proposes the existence of two types of dentigerous cysts: one developmental and the other inflammatory in nature.

Bicuspid↗

PubMed1996

Nucleolar organizer regions (AgNORs) in odontogenic cysts and ameloblastomas.

The aim of this study was to determine whether nucleolar organizer regions (AgNORs) may be of value in distinguishing various odontogenic cysts from the unicystic ameloblastoma. Histological sections were prepared from fifteen cases each of odontogenic keratocyst, residual cyst, dentigerous cyst, unicystic ameloblastoma and conventional ameloblastoma. In each case intra-nuclear AgNOR dots were counted in 100 consecutive basal nuclei. Statistical comparison of the least squares means showed that those areas of unicystic ameloblastomas lined by characteristic epithelium had a significantly lower AgNOR count than the other groups (P < 0.05). The dentigerous cysts had significantly higher AgNOR counts than the residual cysts and unicystic ameloblastomas (P < 0.05). These differences may or may not be indicative of variations in metabolic, proliferative or transcriptional activity. We conclude that AgNOR counts are not of diagnostic significance and cannot be used to distinguish the various odontogenic cysts from one another nor from the unicystic ameloblastoma.

Ameloblastoma↗

PubMed1996

Familial florid cemento-osseous dysplasia--a case report and review of the literature.

Cemento-osseous dysplasia is a fairly common lesion of the jaws originating from the elements of the periodontal ligament. Most lesions do not have a hereditary basis, however a few familial cases have been documented. This is the first report of the florid form of cemento-osseous dysplasia in an African family. The mother, son and one daughter exhibited multiple sclerotic cemental masses of the jaws with large tumour-like swellings in the symphyseal area of the mandible. In the case of the mother the lesions had become infected. The familial form of cemento-osseous dysplasia differs from the non-hereditary type in that the lesions present in children, all cases are florid in nature, there is no predilection for black females, the rate of growth appears to be more rapid and the symphyseal area of the mandible is most severely affected. The mode of transmission appears to be autosomal dominant with variable phenotypic expression.

Adolescent↗

PubMed1995

Vacuolated cells and mucous metaplasia in the epithelial linings of radicular and residual cysts.

The purpose of this study was to determine whether a consistent association exists between mucous cells and clear or vacuolated cells in the epithelial lining of radicular and residual cysts and to consider whether the vacuolated cells may represent a stage in the histogenesis of mucous metaplasia in these linings. Single sections from each of 154 mandibular radicular and residual cysts were stained with periodic acid-Schiff (PAS) after diastase digestion. Fifteen cases which showed mucous metaplasia were included in the study and were examined for the presence of vacuolated cells associated with the mucous cells. Mucous cells were present singly or in groups within all layers of the stratified squamous epithelial lining except the basal cell layer. In nearly all instances small to large ovoid vacuolated cells were found closely associated with the mucous cells. Occasional vacuolated cells contained sparse mucin granules or a delicate network of PAS-positive, diastase-resistant material. It is suggested that the clear cells may represent a stage in the histogenesis of mucous metaplasia.

Epithelium↗

PubMed1992

Rough hypoplastic amelogenesis imperfecta with follicular hyperplasia.

This report documents a unique case of rough hypoplastic amelogenesis imperfecta with apparent anterior oligodontia and multiple anomalies of the associated mesenchymally derived tissues. Multiple unerupted teeth showed hypercementosis, distorted roots with aberrant dentin formation, and marked follicular hyperplasia. The hyperplastic follicles had a complex histopathologic appearance that recapitulated some features of the WHO-type odontogenic fibroma. The features of these teeth, the nature of the associated follicular lesions, and their relationship to the unerupted teeth are discussed.

Adult↗