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Biomedical subjects

D G Gardner

Publications and source records attributed to D G Gardner.

At least 145 records · Page 8Linked to original sources
PubMed1983

Fetal rhabdomyoma of the tongue, with a discussion of the two histologic variants of this tumor.

Fetal rhabdomyomas are rare benign tumors of skeletal muscle that must be distinguished histologically from various sarcomas, including rhabdomyosarcoma. They have recently been subdivided into two histologic variants myxoid and cellular fetal rhabdomyomas, respectively. This article describes the sixth fetal rhabdomyoma to be reported in the oral regions, illustrates the histologic features of the two types, and discusses the means of distinguishing these lesions from various other conditions with which they may be confused.

Diagnosis, Differential↗
PubMed1983

The relationship of plexiform unicystic ameloblastoma to conventional ameloblastoma.

The term plexiform unicystic ameloblastoma refers to a pattern of epithelial proliferation that has been described in cystic lesions of the jaws. It has been considered hyperplastic epithelium, rather than ameloblastoma, by some pathologists because it does not exhibit previously accepted histologic criteria for ameloblastoma. This article provides histologic evidence that plexiform unicystic ameloblastoma is, in fact, a variant of conventional unicystic ameloblastoma by reporting ten cases of unicystic ameloblastoma that exhibit both patterns. Further evidence of the ameloblastomatous nature of plexiform unicystic ameloblastomas is that their biologic behavior, even when this pattern occurs alone, is similar to that of conventional unicystic ameloblastoma.

Adolescent↗
PubMed1983

Multifocal adult rhabdomyoma.

It is not well recognized that a small but significant proportion of extracardiac adult rhabdomyomas have occurred multifocally. The present example of a 60-year-old man with adult rhabdomyomas of the larynx and submandibular region is the seventh multifocal case out of approximately sixty adult rhabdomyomas reported in the literature. Previously published cases are summarized in this article.

Head and Neck Neoplasms↗
PubMed1983

The use of the terms monomorphic adenoma, basal cell adenoma, and canalicular adenoma as applied to salivary gland tumors.

There is considerable confusion in the literature concerning the terms monomorphic adenoma, basal cell adenoma, and canalicular adenoma. This article traces the history of these terms as applied to the pathology of salivary gland tumors and attempts to clarify their usage. It is recommended (1) that monomorphic adenoma be used, as it was originally intended, as a nosologic grouping for all benign epithelial salivary gland tumors that are not pleomorphic adenomas, (2) that basal cell adenoma be used to identify a specific entity that is one component of the monomorphic adenoma group and exhibits a number of histologic subtypes, and (3) that canalicular adenoma be used to describe another entity, distinct from basal cell adenomas but also belonging to the monomorphic adenoma group.

Adenoma↗
PubMed1982

Recombinant DNA.

Explore the source record for details and available documents.

DNA, Recombinant↗
PubMed1982

The peripheral odontogenic fibroma: an attempt at clarification.

Two different lesions of the gingiva that have been referred to previously as peripheral odontogenic fibromas are discussed. The first of these is the rare extraosseous counterpart of the central odontogenic fibroma (WHO type)1 and is therefore referred to in this article as the peripheral odontogenic fibroma (WHO type). It is probably treated adequately by simple excision, but a study of its biologic behavior is lacking. The second lesion is reactive, is common, and has a marked tendency to recur. It has been known by numerous synonyms, including calcifying fibrous epulis and peripheral ossifying fibroma, as well as peripheral odontogenic fibroma. The term peripheral ossifying fibroma should be retained for this lesion to avoid confusion with the peripheral odontogenic fibroma (WHO type).

Adult↗
PubMed1982

Adenosine 3',5'-monophosphate-dependent protein kinase in supernatants from dispersed bovine parathyroid cells.

The presence and characteristics of protein kinase(s) were studied in supernatants of sonicates of dispersed bovine parathyroid cells. cAMP caused a 3- to 5-fold stimulation of protein kinase activity in such extracts, with half of the maximal activation at 4--5 x 10(-8) M cAMP. Protein kinase inhibitor nearly totally abolished both basal and cAMP-stimulated activity, suggesting that most of the activity was cAMP dependent. About 90% of the cAMP-stimulated protein kinase activity eluted from a DEAE-cellulose column at 0.15 m NaCl, consistent with a type II enzyme. The presence of a type II enzyme was also supported by the effects of histone and salt concentrations on enzyme activity; both the basal and cAMP-stimulated activity ratios (activity minus cAMP divided by activity plus 10(-6) M cAMP) were stable in 0.4 M NaCl. The basal activity ratio was not increased by concentrations of histone as high as 10 mg/ml in the protein kinase assay. The predominance of the type II enzyme in dispersed bovine parathyroid cells made it possible to develop conditions for extracting the enzyme from intact intact cells (0.4 m NaCl and 5 mg/ml charcoal), whereby the state of activation of the enzyme remained relatively constant. These studies demonstrate the presence of cAMP-dependent protein kinase activity in dispersed bovine parathyroid cells and define conditions which make it possible to assess the effects of various secretagogues on protein kinase activation in intact parathyroid cells.

Animals↗
PubMed1982

Oral and labial biopsies in amyloidosis and Sjögren's syndrome: meeting and pathologist's needs.

An oral biopsy in a patient suspected of having amyloidosis should be taken from any clinically suspicious area present in the oral mucosa. Such areas include petechiae, ecchymoses, macules, papules, plaques and nonspecific ulcers. If none of these are found, a nondirected biopsy of the gingiva and alveolar mucosa should be performed. The marginal gingiva should be avoided. The labial biopsy for Sjögren's syndrome involves making an incision 1.5 to 2 cm long, parallel to the vermilion border, in the labial mucosa of the lower lip. The incision is widened by blunt dissection and four to seven nodules of salivary gland need to be removed for examination.

Amyloidosis↗
PubMed1981

Plexiform unicystic ameloblastoma: a diagnostic problem in dentigerous cysts.

A plexiform pattern of epithelial proliferation, which does not exhibit the histologic criteria for ameloblastoma published by Vickers and Gorlin, occurs in dentigerous cysts. Some pathologists have diagnosed it as ameloblastoma yet others have considered it to be epithelial hyperplasia. Sections of 19 cases and the limited clinical information available were studied. Histologically characteristic ameloblastoma was found associated with this pattern in nine cases and one case, exhibiting only this pattern, recurred. It is concluded that the pattern in question is in fact ameloblastoma and that Vickers and Gorlin's criteria, although valuable, are too rigid for the diagnosis of this plexiform pattern of ameloblastoma in dentigerous cysts. There is need for further study on the natural behavior of these tumors. However, enucleation with good follow-up examination is probably sufficient for tumors that have proliferated into the cystic lumen, but more extensive surgery is indicated for those involving the periphery of the fibrous connective tissue wall of the cyst. This pattern occurs primarily during the second and third decades of life, generally in the mandible. The term "plexiform unicystic ameloblastoma" is proposed for this lesion to distinguish it from classical plexiform ameloblastoma.

Adolescent↗
PubMed1981

Sodium nitroprusside inhibition of parathyroid hormone release is not mediated through cyclic GMP.

Sodium nitroprusside effected a rapid, dose-dependent increase in intracellular cGMP accumulation in freshly dispersed bovine parathyroid cells. The effect was half-maximal between 10(-4) and 3 X 10(-4)M, maximal at 3 X 10(-3)M nitroprusside and could be amplified (approximately 50%) by the addition of methylisobutylxanthine (4 X 10(-4)M). The dose-response characteristics were similar to those previously described for the inhibition of cAMP accumulation and PTH release by this agent. Neither dibutyryl cGMP (10(-3)M) nor 8'-bromo-cGMP (10(-3)M) mimicked the inhibitory effect of nitroprusside on cAMP accumulation or PTH release. Dose-dependent stimulation of guanylate cyclase was found in a particulate preparation of parathyroid cells; activity was maximal at 10(-4)M nitroprusside while higher concentrations appeared to inhibit the enzyme. Nitroprusside significantly reduced both (-)isoproterenol and guanine nucleotide-stimulated adenylate cyclase activity in the particulate preparation with maximum inhibition between 10(-3)-10(-2)M. cGMP concentrations as high as 10(-4)M did not affect agonist-stimulated cAMP synthesis. Thus, although the kinetic and dose-response characteristics of the nitroprusside effect on cGMP suggest a linkage to its previously described effects on cAMP and PTH secretion, no direct evidence was found to indicate a causal relationship between the two. Rather it would appear that the effects on the adenylate and guanylate cyclase enzymes occur in parallel, possibly the result of some common primary perturbation of cellular physiology.

Adenylyl Cyclases↗
PubMed1981

Effect of potassium on PTH secretion from dispersed bovine parathyroid cells.

The effects of potassium on PTH secretion were studied in dispersed bovine parathyroid cells. Removal of extracellular potassium markedly inhibited low calcium-stimulated PTH release. This inhibition was dose-dependent, with a half-maximal effect at 1-2 mM. Above 2-3 mM potassium, there was relatively little further increase in maximal secretory rate, but there was a progressive increase in the "set-point" for calcium-regulated PTH release, analogous to that which we have observed previously with lithium. These changes in secretory function were not associated with any change in cellular cAMP. Low extracellular potassium, however, caused a striking reduction in the ratio of intracellular potassium to sodium, while a reciprocal change was brought about by high extracellular potassium. These studies suggest that alterations in secretory function induced by changes in extracellular potassium, which are phenomenologically similar to those found in states of pathologic parathyroid function in man, may be related to changes in intracellular monovalent cations.

Animals↗
PubMed1980

The treatment of ameloblastoma based on pathologic and anatomic principles.

A number of important factors must be considered in planning the treatment of ameloblastoma. It is essential to distinguish among the three clinical types of ameloblastoma--the intraosseous solid or multicystic lesion, the well-circumscribed unicystic type, and the rare peripheral (extraosseous) ameloblastoma--because they require different forms of treatment. Unicystic ameloblastomas in which the tumor extends into the lumen of the cyst or involves only the cystic lining can be expected to be removed completely by enucleation. This approach, however, is inadequate if the tumor has invaded the periphery of the fibrous connective tissue wall. Ameloblastomas may invade the intertrabecular spaces of cancellous bone but do not invade compact bone, although they may erode it. Ameloblastomas in the posterior part of the maxilla should be treated more extensively than similar lesions in the mandible because of the proximity of the posterior maxilla to vital structures and the difficulty in treating any recurrences. This article discusses the treatment of ameloblastoma based on these pathologic and anatomic considerations and includes brief discussions of the role of cautery, cryotherapy, and radiotherapy.

Ameloblastoma↗
PubMed1980

Histogenesis of the lateral periodontal cyst and the gingival cyst of the adult.

The clinical and morphologic similarities of the LPC and the GCA strongly suggest that these two cysts share a common histogenesis and represent the intraosseous and extraosseous manifestations of the same lesion. The most striking similarity is the morphologic resemblance of the clear cells of dental lamina rests of dental lamina rests to those lining the LPC and GCA. The common association of these clear-cell rests of dental lamina with both the LPC and the GCA, and observations on their natural history, suggest that they are the source of the epithelium of both the LPC and GCA.

Adult↗