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Biomedical subjects

A P Chaudhry

Publications and source records attributed to A P Chaudhry.

At least 19 recordsLinked to original sources
PubMed1991

Malposed sublingual gland in the anterior mandible: a variant of Stafne's idiopathic bone cavity.

This article reports a case of an asymptomatic, ill-defined radiolucency in the anterior mandible in the region of the central and lateral incisor teeth, found on routine roentgenographic examination. A labial mucoperiosteal flap was raised under local anesthesia. A portion of the lingual plate and inferior border of the anterior mandible were missing, and the space was occupied by the sublingual gland extension. The entrapped sublingual gland was removed and the histological diagnosis confirmed. The mucoperiosteal flap was sutured back in position. Healing was uneventful.

Adult↗
PubMed1990

Mucous membrane pemphigoid: a case report.

A protracted 30-year course of oral mucous membrane pemphigoid, with repeated exacerbations and remissions, is reported in an 83-year-old white woman. Its clinical, microscopic, and immunologic features are discussed in this article for differential diagnosis from other mucocutaneous vesiculo-bullous diseases.

Aged↗
PubMed1989

Adult benign granular cell tumor of the maxilla.

A granular cell tumor occurred in the right anterior maxilla of a 22-yr-old black man. It involved the right labial maxillary submucosa and the underlying bone. It also invaded the maxillary sinus and the nasal cavity on the same side. The ultrastructural features of the lesion confirmed the biopsy diagnosis of benign granular cell tumor. The treatment involved partial maxillectomy, split thickness skin graft and immediate dental prosthesis.

Adult↗
PubMed1989

Ultrastructural study of the histogenesis of salivary gland mucoepidermoid carcinoma.

This electronmicroscope study of the histogenesis of mucoepidermoid carcinoma is based on 15 cases from the major and minor salivary glands. Six major cell types were identified: undifferentiated (cuboid) stem cells, intermediate (columnar) cells, serous/mucoid secretory cells, mucus-producing goblet cells, squamous/epidermoid cells and myoepithelium. It is proposed that undifferentiated stem cells serve as pluripotential reserves which give rise to the various cell types seen in mucoepidermoid carcinoma. Reserve cells in the acinar-intercalated duct components of the salivary glands appeared to give rise to the serous/mucoid and myoepithelial cell populations of mucoepidermoid carcinoma. Reserve cells in the proximal ducts system (intra/extralobular striated ducts and excretory ducts) differentiated into myoepithelium, intermediate (columnar) cells, squamous/epidermoid and mucus-producing goblet cell lines. It is proposed that neoplastic reserve cells give rise to different tumor types in the salivary glands. These types result from varying admixtures and arrangements of tumor cells at different stages of their structural and functional cytodifferentiation from reserve cells. It is further proposed that neoplastic reserve cells differentiate along similar cell lines as the embryonic "stem cells" in the development of normal salivary glands.

Adult↗
PubMed1987

Ultrastructure of normal human parotid gland with special emphasis on myoepithelial distribution.

The myoepithelium in human parotid, unlike that in other species, is not limited to the acinar-intercalated ductal system but extends to the intra- and extralobular striated ducts. Myoepithelial cells of the striated ducts are smaller, fewer, and different in shape but they are similar in their relationships and ultrastructural morphology to the acinar-intercalated system. Distribution of myoepithelium is discussed with respect to its role and participation in the histogenesis of salivary gland tumours, especially those of intermediate and large duct cell origin.

Adenoma, Pleomorphic↗
PubMed1986

Histogenesis of adenoid cystic carcinoma of the salivary glands. Light and electronmicroscopic study.

This ultrastructural study, based on 12 cases of adenoid cystic carcinoma of the major and minor salivary glands, was conducted to determine the role and extent of participation of myoepithelial cells in their histogenesis. The tumors were composed of four major cell types; intercalated duct, myoepithelial, secretory, and pluripotential reserve/stem cells. The cellular composition of adenoid cystic carcinoma is similar to that in the "terminal tubule" complex stage of a developing salivary gland except that in the tumor the pluripotential reserve/stem cells differentiate predominantly along the intercalated duct cell line rather than secretory cells as in the acinic cell carcinoma. Furthermore, adenoid cystic carcinoma appears to contain a far greater number of myoepithelial cells than acinic cell carcinomas.

Adult↗
PubMed1986

Light and ultrastructural features of lymphoepithelial lesions of the salivary glands in Mikulicz's disease.

This investigation deals with the histogenesis of the so-called 'epimyoepithelial islands' in Mikulicz's disease of the major salivary glands and is based on light and electron microscopic study in six patients. The 'epimyoepithelial islands' represent collapsed acini prior to their complete involution and disappearance, the intraductal cellular proliferation, stratification and differentiation into luminal and peripheral myoepithelial cells with partial and complete obliteration of their lumina and finally, cord-like proliferation and formation of nests of residual pluripotential cells showing squamous metaplasia and occasional myoepithelial cell differentiation. A pink, homogeneous and hyaline material on light microscopic examination is multilayered and extracellular and is in close association with the basal lamina when viewed with electron microscope.

Adult↗
PubMed1986

Histogenesis of acinic cell carcinoma of the major and minor salivary glands. An ultrastructural study.

This study describes the light microscopic, histochemical and electron-microscopic findings of 10 acinic cell carcinomas from the major and minor salivary glands. Ultrastructurally, four cell types were identified: secretory acinar cells, intercalated duct-like cells, pluripotential reserve/stem cells and myoepithelial cells. This cellular composition suggests that the tumours are derived from neoplastic proliferation, cytodifferentiation and functional maturation of pluripotential reserve/stem cells which normally reside at the acinar-intercalated duct junctions and/or in the intercalated ducts proper of adult salivary glands. This study further supports the concept that different salivary gland tumours recapitulate various developmental stages in the normal embryogenesis of the salivary glands.

Aged↗
PubMed1986

Development of the hamster submandibular gland. II. The ductal system.

The major secretory duct is differentiated from the SMG anlage in early embryogenesis and undergoes minor morphologic changes from its inception until full maturation. Structurally, the ducts appear to be suited for a conduit function. At birth, the extralobular and intralobular ducts arise directly from the major duct or indirectly from the primary and secondary branches, respectively. They are distinguishable from each other by their topography only. However, developmentally, intralobular ducts give rise to 'terminal tubule' complexes but no such function is performed by the extralobular ducts. Both duct types first show distinct evidence of striation of their cells at one week after birth. Their lateral and basal infoldings, interdigitations and close association with mitochondria provide them with increased surface area and a source of energy for exchange of ions and fluids. The differentiation of convoluted granular ducts begins at 2 weeks of age with the appearance of membrane-bound and dense secretory granules in the apical cytoplasm of the luminal cells. The changes start in the proximal segment of the intralobular striated duct, and extend to occupy a large part of it in a mature 6-week old animal. These ducts comprise the bulk of the ductal system. The distribution of the granules is size-gradient dependent, the small granules being near the lumen and the large ones being close to the nucleus. The morphologic features of CGD are in keeping with absorptive and secretory functions.

Aging↗
PubMed1985

Development of the hamster submandibular gland. I. The acinar-intercalated duct complex.

On the basis of light and electronmicroscopic observations of the prenatal and postnatal development of the hamster submandibular gland, several stages of cyto-morphodifferentiation were identified. The initial critical period was between the 13th and 14th day of gestation. An anlage of 'undifferentiated' pluripotential stem cells was transformed into terminal tubules which consisted of secretory cells, myoepithelial cell precursors and stem cells. From the periphery of the terminal tubules originated terminal buds which were the forerunners of the acini. The intercalated ducts, terminal tubules and terminal buds constituted the 'terminal tubule complex'. Several morphological similarities were noted between the hamster and the rat developing SMG and between the hamster developing SMG and the rat parotid. It seemed that various human salivary gland tumors recapitulated different stages of their normal cytomorphogenesis.

Aging↗
PubMed1983

Glycogen-rich tumor of the oral minor salivary glands. A histochemical and ultrastructural study.

A detailed electronmicroscopic study on glycogen-rich tumor is presented. The neoplasm originated from the minor salivary glands on the ventral surface of the tongue. The role of myoepithelial cells in the histogenesis of this lesion is not supported. It is proposed that the tumor arises from "undifferentiated" stem cells analogous to cells in the "end bud" stage of salivary gland morphogenesis. The presence of a large amount of glycogen is secondary to defective carbohydrate metabolism within the tumor cells.

Adenoma↗
PubMed1983

Monomorphic adenomas of the parotid glands. Their ultrastructure and histogenesis.

Three cases of monomorphic basal cell adenoma of the parotid glands were studied with light microscopy. In one patient, fresh tissue was available for electron microscopic observations. On the basis of ultrastructural findings it was concluded that myoepithelial cells play little, if any, role in the histogenesis of this lesion. The tumor originates from the undifferentiated stem cells analogous to the cells seen at the "end bud" stage of salivary gland morphogenesis prior to their further cytodifferentiation and functional maturation into secretory and myoepithelial cells. In fully developed salivary glands such undifferentiated stem cells reside as "reserve" cells in the intercalated ductal system.

Adenoma↗
PubMed1983

Ultrastructure of monomorphic adenoma (ductal type) of the minor salivary glands.

A monomorphic adenoma (ductal type) of the palatal minor salivary glands is reported. Ultrastructurally, the predominant tumor cells contained zymogenlike dense secretory granules. There was a continuum from tumor cells with little or no secretory granules to ones with increasing numbers of granules. Except for that, the tumor cells shared many of their fine structural features. Histogenetically, the tumor originated from neoplastic proliferations of "undifferentiated" stem cells corresponding to "end-bud" stage of salivary glands embryogenesis. Under neoplastic influences, such cells underwent further cytodifferentiation and functional maturation along the secretory cell lines. In mature salivary glands, such pluripotential cells reside as "reserve" cells in the intercalated ducts.

Adenoma↗
PubMed1983

Prenatal and postnatal histogenesis of myoepithelium in hamster submandibular gland. An ultrastructural study.

Prenatal and postnatal development of myoepithelium in the hamster submandibular gland has been studied by electronmicroscopy. Myoepithelial cells originate from 'undifferentiated' stem cells in the epithelial anlage at 14-1/2 days of gestation. At this stage of their cytodifferentiation, the myoepithelial cells are recognizable by their elongated shape, peripheral location between the basal lamina and other epithelial cells in the anlage, axially oriented dense nucleus and low density cytoplasm. The myofilament deposition starts at birth, initially in the basal cytoplasm. With advancing maturation, there is a progressive increase in the number of myofilaments and in two week-old animals they virtually fill the cytoplasm. The mature myoepithelial cells are characterized by their shape, location, cytoplasmic myofilaments which run parallel to the basal lamina and display focal densities along their course, hemidesmosomes and pinocytotic vesicles. The morphologic evidence supports their epithelial origin but militates against their ability to mediate the synthesis of fibrous, mucinous, chondroid or osseous material as proposed by others (Grishman, 1952; Azzopardi and Smith, 1959; Doyle et al., 1968; Hubner et al., 1971).

Epithelium↗