Acinar phenotypes in salivary pleomorphic adenoma: unusual differentiation or disordered functional activity?

To explain the occurrence in salivary pleomorphic adenoma of structures with an arrangement and appearance of tumour cells resembling acini, two tumours showing such structures and, for comparison, a tumour showing goblet cells were examined with the use of histochemistry and immunocytochemistry for constituents of the salivary secretory process. One tumour consisted mainly of slightly granular cells with an acinar arrangement, which contained neutral and carboxylated glycoproteins, -SH groups and cytoplasmic epithelial membrane antigen. The second tumour showed a minor component of structures resembling mucous acini, which contained neutral and carboxylated glycoproteins, -SS- groups and fucoglycoconjugates. The goblet cells of the third tumour contained sulphated glycoproteins and were associated with cystic lumina. Acinar phenotypes in salivary pleomorphic adenoma could reflect either an unusual line of differentiation or luminal cells with increased synthesis and/or retention of variably mature glycoproteins different from those of goblet cells. Disordered secretion and externalization of glycoproteins are possible factors influencing phenotypes in this tumour.

Variations of lead isotopes and airborne particulate concentrations from the Kozani basin, West Macedonia, Greece

The spread and variation in 206Pb/207Pb ratios make Pb isotopes a powerful tool when it comes to detecting trends in airborne particulates originating mainly from power plants. This study was conducted to determine the source of pollution in Kozani area, an affected industrial area. Lead isotopic ratios of air filters under certain meteorological conditions were compared to Pb isotope analyses sampled from lignite mines, but also to Pb isotope analyses of cultivations in soil originating from the reclamation of old abandoned lignite-mines. The particles taken into consideration have an aerodynamic diameter less than 10 microm (PM10). The measurements were carried out in a central part of the town of Kozani, West Macedonia, for one year observation period. The lead isotope values of air filters and of wheat in the Kozani area are between the values of lignite Pb and of Greek gasoline.

Histochemical phenotypes of von Ebner's gland of ferret and their functional implications

Von Ebner's gland of ferret was examined by means of light microscopy, protein, mucosubstance and enzyme histochemistry, and neurohistology. Acinar cells were replete with granules containing neutral mucosubstances and disulphides, and showed strong diffuse acid phosphatase activity and weak granular staining for peroxidase. Staining for cytochrome oxidase, succinate dehydrogenase, and NADH and NAD(P)H dehydrogenases was also seen. Basolateral plasmalemma of acinar cells showed weak, ouabain-sensitive Na+,K+-ATPase activity. Ductal cells were of a simple appearance, contained thiols and showed variable staining for acid phosphatase, dehydrogenases and cytochrome oxidase. Variable amounts of beta-glucuronidase reaction product were localized in the glandular parenchyma, being marked in atrophic areas. Prominent stellate myoepithelial cells embracing acini and also basal ductal cells were demonstrated by alkaline phosphatase. Thiamine pyrophosphatase reaction product was concentrated in blood vessels around parenchyma, with little Golgi-like staining in acinar cells. Acetylcholinesterase activity was associated with an extensive network of nerve fibres embracing parenchyma, whereas catecholamine fluorescence was not seen. The results suggest that the acini of von Ebner's gland of ferret synthesise neutral secretory glycoproteins and peroxidase. Water mobilization is inconspicuous. Lysosomal activities feature in the parenchyma, possibly a consequence of processing secretory products in acini, absorption in ducts and/or adaptation atrophy. The gland receives a rich cholinergic-type innervation, and has extensive myoepithelial and microvascular networks.

Phenotypes in canalicular adenoma of human minor salivary glands reflect the interplay of altered secretory product, absent neuro-effector relationships and the diversity of the microenvironment

AIMS

Uncertainty about the factors influencing phenotypes in salivary canalicular adenoma prompted the present investigation.

METHODS AND RESULTS

Specimens of canalicular adenoma from 15 patients were examined with the use of histology, histochemistry for protein, mucosubstances and pigments, nerve staining and immunocytochemistry for cytoskeleton components. The tumours consisted largely of simple cells lining tubules that were occasionally cystic or branching and budding, and were set in loose, vascular and often haemorrhagic stroma. Other phenotypes recognized were mucous cells, apocrine-like cells, pigmented cells, microliths and stromal macrophages, detected in 26.6%, 20%, 33.3%, 20% and 53. 3% of the patients, respectively. Simple cells showed moderate levels of -SH groups and strong immunoreactivity for 'simple' epithelial phenotype cytokeratin. The simple cells lining cystic tubules showed additional immunoreactivity for 'stratified' epithelial phenotype cytokeratin, possibly an adaptation to mechanical pressure. Lumina showed variable levels of neutral and carboxylated glycoproteins, and chondroitin sulphate. Stroma showed high levels of chondroitin sulphate and hyaluronic acid. Mucous cells showed high levels of -SS- groups and nonsulphated glycoproteins. Apocrine-like cells contained lipofuscin. Pigmented cells contained haemosiderin, possibly a consequence of localized iron overload. Microliths contained mucosubstances. Macrophages often contained lipofuscin. No nerves were found in relation to the tumours.

CONCLUSIONS

The results suggest that, contrary to popular belief, phenotypes in canalicular adenoma do not reflect histogenetic concepts but rather may derive from the interplay between an altered secretory product, consisting of glycosaminoglycan and an immature form of glycoprotein, the lack of neuro-effector relationships and the different microenvironments throughout the tumour.

Innervation and myoepithelial arrangements in the submandibular salivary gland of ferret investigated by enzyme, catecholamine and filament histochemistry

Although the submandibular gland of ferret is useful for studying salivary secretory processes which are regulated by nerves and involve myoepithelial activity, little attention has been paid to its parenchymal innervation and myoepithelial arrangements. Therefore, glands obtained postmortem from mature ferrets of both sexes were here examined with the use of light-microscopic histochemical techniques for cholinesterases, phosphatases and phosphorylase, histofluorescence for catecholamines, and milling dyes. Acetylcholinesterase staining was associated with nerve trunks in the interlobular stroma and an extensive intralobular network of nerve fibres, presumably of a cholinergic type, embracing acini and ducts. There were fewer fibres containing fluorescing catecholamines, presumably adrenergic. They were largely associated with acini. Numerous stellate cells with fine branching processes embracing acini, presumably myoepithelial cells, and a few spindle-shaped basal cells, investing striated ducts, were demonstrated on frozen tissue by alkaline phosphatase, but not by adenosine triphosphatase, inosine diphosphatase and phosphorylase. Cells of similar shape and distribution were also demonstrated by staining with milling dyes on fixed tissues, indicating possibly a filamentous constituent conferring mechanical stability and/or contractile ability. Together, these results suggest, firstly, that a cholinergic-type parenchymal innervation is prominent in the submandibular gland of ferret, although many adrenergic nerves are also present, and, secondly that the gland has a very extensive myoepithelial network which is possibly involved in membrane transport, and the support and or contraction of the secretory parenchyma.

Morphological phenotypes and functional capabilities of submandibular parenchymal cells of the ferret investigated by protein, mucosubstance and enzyme histochemistry

Submandibular glands obtained post-mortem from mature ferrets of both sexes were examined with the use of light microscopical histochemical methods for proteins, mucosubstances and enzymes associated with cell functions or organelles. Demilunar cells showed carboxylated mucosubstances that were mainly non-sulphated, and diffuse activity for peroxidase, E600-sensitive esterase and acid phosphatase. Thiol groups were also detected in these cells. Central acinar cells showed sulphated mucosubstances, disulphides and reticular staining for thiamine pyrophosphatase. Intercalary ducts showed diffuse activity for NADH and NAD(P)H dehydrogenases. Striated ducts contained protein, tryptophan, disulphides, neutral mucosubstances and E600-sensitive esterase periluminally. Basally, the striated ductal cells showed variable activity for peroxidase, cytochrome oxidase, succinate dehydrogenase and acid phosphatase. Basolateral plasma membranes of these cells exhibited ouabain-sensitive Na,K-ATPase activity. The collecting ducts were characterized by variable periluminal staining for acid phosphatase, beta-glucuronidase, acid beta-galactosidase and E600-resistant esterase. The results suggest that the histological appearances of the acini of the submandibular gland of the ferret are dependent on the synthesis of secretory acid glycoproteins, that the striated ducts are involved with the secretion of tryptophan-rich product comprising neutral glycoproteins and showing esterase activity and with marked transport of ions and that the collecting ducts are involved with absorption.

Ultrastructural observation of arteriolar calcification in a submandibular salivary gland

Foci of calcification were found ultrastructurally in the wall of an arteriole of a specimen of chronic submandibular sialadenitis. They were seen in the basement membrane surrounding the smooth muscle cells, where some of them were associated with vesicles and membraneous debris, and in a macrophage. Calcium and phosphorus were detected microanalytically in the calcifications, which contained needle-shaped crystals. The calcifications in the basement membrane may have started in vesicles released from smooth muscle cells and those in the macrophage may have arisen by heterophagy. Matrix vesicles appear to be of significance in arteriolar calcification and macrophages may offer protection against it.

Microlithiasis in parotid sialadenosis and chronic submandibular sialadenitis is related to the microenvironment: an ultrastructural and microanalytical investigation

AIMS

Microlithiasis was investigated in parotid sialadenosis and chronic submandibular sialadenitis to determine if it relates to the glandular microenvironment as has been found experimentally.

METHODS AND RESULTS

Semithin sections were stained by a mixture of methylene blue and Azure II followed by basic fuchsin, which stains calcified parts of microliths red and organic parts green, and ultrathin sections were examined electron microscopically and microanalytically. Microliths in sialadenosis were found in periacinar stroma, in which necrotic acinar cells were found, and in parenchyma, and consisted of consolidated organic material with little or no crystalline calcium. Microliths in sialadenitis were found in stroma, particularly around intercalary ducts, in lumina and in parenchyma, and contained much crystalline calcium. Macrophages enclosed some microliths.

CONCLUSIONS

The paucity of calcium in microliths in sialadenosis and the abundance in sialadenitis relates to the glandular calcium. The periacinar distribution of microliths in sialadenosis possibly relates to formation in periacinar necrotic debris. The distribution of microliths in sialadenitis around intercalary ducts possibly relates to formation in matrix vesicles formed from atrophic parenchyma, and in lumina to formation in stagnant secretory material. Microliths appear to be scavenged by macrophages. Thus the experimental finding that salivary microlithiasis relates to the microenvironment pertaining in humans.

Cytological and cytochemical investigations on granular cells in oral lichen planus

Two biopsy specimens showed unusual histology characterized by features consistent with resolving oral lichen planus and voluminous, finely granular cells in the lamina propria, resembling the cells of granular cell tumour. Immunocytochemistry and lipid-pigment histochemistry indicated that the granular cells are macrophages of low proliferative activity laden with early ceroid. It is likely that damaged basal keratinocytes provide debris for the formation of the latter. "Oral ceroid granuloma' would be an appropriate term for collections of such reactive macrophages occurring in the oral tissues.

Cytological and cytochemical investigations on granular cells in oral lichen planus

Two biopsy specimens showed unusual histology characterized by features consistent with resolving oral lichen planus and voluminous, finely granular cells in the lamina propria, resembling the cells of granular cell tumour. Immunocytochemistry and lipid-pigment histochemistry indicated that the granular cells are macrophages of low proliferative activity laden with early ceroid. It is likely that damaged basal keratinocytes provide debris for the formation of the latter. 'Oral ceroid granuloma' would be an appropriate term for collections of such reactive macrophages occurring in the oral tissues.

Desmoplastic trichoepithelioma of the upper lip. A case report with histochemical features and observations on its histogenesis

A case of desmoplastic trichoepithelioma of the upper lip investigated by histochemistry and immunocytochemistry is presented. There was histologic suggestion of cytoplasmic vacuolation that does not appear to have been previously described. Histochemical examination indicated the presence of glycogen within tumor cells and a reparative-type stroma. Immunocytochemical examination revealed variable reactivity for high molecular weight cytokeratin and colonization by Langerhans' cells. The observations suggest a follicular and sudoriferous differentiation for desmoplastic trichoepithelioma and hence an origin from a pluripotential adnexal keratinocyte.

Myositis ossificans traumatica of sternocleidomastoid muscle presenting as cervical lymph-node metastasis

It is well known that clinical assessment of the metastatic status of the cervical lymph nodes in patients with squamous cell carcinoma of the upper aerodigestive tract is frequently inaccurate, and several causes for false-positive assessments are well described. We report a novel cause, namely, a case of myositis ossificans traumatica of the sternocleidomastoid muscle, which presented as a neck mass after a direct laryngoscopy for biopsy of a laryngeal squamous cell carcinoma. The importance of this lesion is that it should be considered in the clinical differential diagnosis of swellings in the neck.

Unpigmented intramucosal nevus of palate. An unusual clinical presentation

A case of unpigmented intramucosal nevus occurring in the palatal mucosa is described. It presented as a nodule and was diagnosed clinically as fibroma. The correct diagnosis was established histologically and immunohistochemically; the importance of this lesion is that it should be considered in the differential diagnosis of oral soft-tissue tumors.

The effects of obstruction and secretory stimulation on microlithiasis in salivary glands of cat: light and electron microscopy

Obstruction and increased secretory activity are considered to be important aetiological factors of salivary microlithiasis, which may itself be an aetiological factor of sialadenitis. However, there is a lack of substantial evidence for the importance of obstruction, and investigations on increased secretory activity used pathological doses of pharmacological agents. Therefore further investigation of these factors is essential. Feline parotid, submandibular and sublingual salivary glands, in which microliths occur normally as in man, were examined after ductal ligation to produce obstruction, electrical stimulation of the glandular nerves to produce increased secretory activity, or both. Microliths were detected in: 0 out of 38 untreated, 1 out of 55 ligated, 2 out of 17 stimulated and 2 out of 17 stimulated ligated submandibular glands; 6 out of 29 untreated, 7 out of 46 ligated, 3 out of 12 stimulated and 4 out of 14 stimulated ligated sublingual glands; and no parotid glands. The chi 2 test confirmed that the experimental procedures did not produce an increased occurrence of microliths. Microliths were detected in parenchymal cells, intercellularly in atrophic parenchyma, intraluminally, interstitially and in macrophages. The present investigation indicates that obstruction and increased secretory activity are not important aetiological factors of salivary microlithiasis.

Histochemical and biochemical determination of calcium in pleomorphic adenoma

Although calcification seldom occurs in pleomorphic adenoma, it often occurs in salivary glands, and so we decided to investigate the possible role of calcium in this difference. A histochemical method using glyoxal bis(2-hydroxyanil) demonstrated a small amount of calcium outlining lumina and separated cells of epithelial structures and associated with cells of myxoid and chondroid regions in pleomorphic adenoma, and a conspicuous amount in the acini of the associated salivary glands. A biochemical method using dry ashing demonstrated a significantly higher level of calcium in the glands than in pleomorphic adenoma. The results indicate that the calcium is mainly associated with secretory granules, which are scarce in pleomorphic adenoma, and with proteoglycan present intercellularly and in stromal regions of pleomorphic adenoma. The calcium in secretory granules is of possible importance in calcification in lumina and epithelium, and that bound to proteoglycan is possibly released following necrosis to be of importance in stromal calcification. However, the overall low level of calcium in pleomorphic adenoma is the likely explanation for the usual lack of calcification.

Ultrastructural localization of microliths in salivary glands of cat

Although microliths occur in normal human salivary glands and may be an aetiological factor of sialadenitis, little is known of their natural history. In an attempt to remedy this, we investigated a large archival collection of normal and experimental feline parotid, submandibular and sublingual salivary glands. In submandibular and sublingual glands, microliths were detected ultrastructurally in: all types of acinar secretory cells; myoepithelial cells; ductal cells; lumina; intercellular spaces; basement membrane; stroma; macrophages; multinuclear giant cells; and neutrophils. Microliths were not detected ultrastructurally in parotid glands. Microliths appear to form in acinar cells during autophagy and in stagnant secretory material in lumina. Microliths appear to be removed by secretion in the saliva, discharge from cells laterally and basally, and engulfment by macrophages. There appears to be a turnover of microliths, which possibly is upset by secretory inactivity with a resulting accumulation that leads to localized obstruction and sialadenitis.

Histochemical and biochemical determination of calcium in salivary glands of cat

Although feline salivary glands have been used in investigations on secretion and microlithiasis and both processes involved calcium, nothing is known about its distribution in these glands. Therefore we have demonstrated the presence of calcium by a histochemical technique using glyoxal bis(2-hydroxyanil) and a biochemical technique using dry ashing. The histochemical technique stained serous acinar cells weakly and rarely found mucous acinar cells strongly in the parotid gland, mucous acinar cells moderately to strongly and serous acinar cells weakly in the sublingual gland, and central and demilunar acinar cells moderately to strongly in the submandibular gland. The biochemical technique revealed less calcium in the parotid than in the submandibular and sublingual glands. Both techniques revealed a decrease of calcium in submandibular and sublingual glands following parasympathetic stimulation. The histochemical distribution of calcium, which corresponds to that of acinar secretory glycoprotein, and the loss of calcium following parasympathetic stimulation, which causes release of secretory granules, indicate the presence of calcium in secretory granules. The concentration of calcium in the different types of acinar cell corresponds to the acidity of the secretory glycoprotein and suggests that calcium is present as a cationic shield to allow the condensation of polyionic glycoprotein in secretory granules.

Microliths in normal salivary glands of cat investigated by light and electron microscopy

This investigation concerns the natural history of microlith in the salivary glands of cat. Microliths were detected in more sublingual than submandibular glands and were almost absent in the parotid. They were found intraparenchymally, intraluminally and interstitially, and ultrastructurally in phagosomes of acinar, ductal and myoepithelial cells, intermixed with the cytoplasm of degenerate acinar cells, and in intraparenchymal macrophages and a multinuclear giant cell. They appear to form in healthy acinar cells during autophagocytosis, and possibly to be discharged luminally, laterally or basally, and to form in the debris of degenerate cells intraparenchymally and intraluminally. They appear to be removed by expulsion in the saliva, scavenging macrophages, and possible eventual degradation in the parenchymal phagosomes. The greater occurrence of microliths in the sublingual gland may relate to a low level of secretory activity, and the near absence of microliths in the parotid to a low level of calcium. The feline salivary glands were found to be an outstanding model for the investigation of microlithiasis.

Analytical ultrastructural investigation of microliths in salivary glands of cat

Microliths in Araldite-embedded pieces of submandibular and sublingual glands of cat were stained in semithin sections by Methylene Blue and Azure II followed by Basic Fuchsin, and were examined in ultrathin sections by electron-microscopical X-ray microanalysis. Calcium and phosphorus were detected in substantial aggregates of crystals that were stained by Basic Fuchsin and appeared to be hydroxyapatite, but were not detected in granular material that was stained by Methylene Blue and Azure II and appeared to be organic. The polychromatic stain thus appears to be a useful indicator of calcified material. The majority of microliths in acini contained substantial aggregates of crystals, whereas the majority of those in ducts did not. This corresponds to the distribution of the glandular calcium, and suggests that microliths are variously enriched with calcium according to its local level.

Production of salivary microlithiasis in cats by parasympathectomy: light and electron microscopy

Salivary glands of cat were examined from 1 to 42 days following parasympathectomy and compared with contralateral normal control glands. Microliths were detected by light microscopy in none of 11 parotid, 31 out of 41 submandibular and four out of 22 sublingual glands following parasympathectomy, and one out of 19 parotid, five out of 28 submandibular and four out of 15 sublingual normal control glands. The greatly increased occurrence of microliths in the submandibular gland was statistically significant. Microliths in the parasympathectomized submandibular glands were detected by light microscopy most often in ductal lumina, followed by acinar lumina, ductal parenchyma, interstitial stroma, and acinar parenchyma. They were detected by electron microscopy also in the basement membrane overlying protruding processes of myoepithelial cells and in intraparenchymal macrophages. Intracellular microliths were in phagosomes. In the parasympathectomized submandibular glands, parenchymal atrophy was seen and particularly involved the striated ducts; secretory material and cellular debris were seen in lumina; and macrophages and neutrophils were more apparent than normally. The great increase of microlithiasis in the submandibular gland appears to be the result of secretory inactivity, and microliths appear to form in stagnant secretory material and cellular debris in lumina and in phagosomes of parenchymal cells.

The effect of sympathectomy on the occurrence of microliths in salivary glands of cat as studied by light and electron microscopy

Parasympathectomy is followed by a greatly increased occurrence of microliths in the feline submandibular gland, which appears to be because of secretory inactivity. The sympathetic nerves are also important in secretory processes, and so feline submandibular, sublingual and parotid glands subjected to postganglionic sympathectomy for periods from 1 day to 1 yr have now been investigated. Microliths were detected in two out of 28 sympathectomized submandibular glands and four out of 27 untreated glands, and in 10 out of 22 sympathectomized sublingual glands and seven out of 19 untreated glands. There were no significant differences between the occurrence of microliths in sympathectomized and untreated glands. Microliths were not detected in any of 29 sympathectomized and 30 untreated parotid glands. The appearance of the sympathectomized glands was similar to that of the untreated glands. The failure of sympathectomy to affect the occurrence of microliths or the appearance of the glands is possibly because of parasympathetic nerve impulses, which produce continuing secretory activity, and also the spontaneous secretion of the sublingual gland. The results support the concept that secretory inactivity is an aetiological factor of microlithiasis.

Histochemical and biochemical determination of calcium in salivary glands with particular reference to chronic submandibular sialadenitis

Although salivary calcification is relatively common, little is known about the localization and content of the calcium of normal and diseased human salivary glands. We investigated this in chronic submandibular sialadenitis with a variable mixture of relatively normal and extremely atrophic parenchyma and in normal submandibular, parotid and palatal glands. Calcium was localized histochemically in mucous acinar cells of submandibular and palatal glands at moderate to high levels, in serous acinar cells of submandibular and parotid glands at low to moderate or occasionally high levels, in mucous ductal cells at moderate to high levels, and in extremely atrophic parenchyma at low levels or not at all. Calcium was determined biochemically at relatively high levels in the different glands in the order palatal, submandibular, sialadenitis and parotid. However, the differences were small. The results indicate that most salivary calcium is associated with secretory granules; this is the likely source of the calcium involved in salivary calcification.

Increase of microliths in inactive salivary glands of cat

Secretory inactivity could be a factor in the formation of microliths, and so their occurrence in feline salivary glands after the secretory inactivity produced by parasympathectomy was investigated. Parasympathectomy was followed by a greatly increased occurrence of microliths in the submandibular salivary gland, but not in the parotid and sublingual, which may relate to residual secretory activity in these glands. This discovery suggests that secretory inactivity may indeed be a factor in the production of microliths in human salivary glands, and consequently of chronic sialadenitis and sialothiasis.

Changes in serum lipids in rats treated with PGF2 alpha

Serum lipid concentrations were determined in rats treated with PGF2 alpha, PGE1, and controls. Administration of PGF2 alpha in rats influenced only the HDL lipid composition. HDL-cholesterol decreased while HDL-triglycerides increased. No significant difference was observed in the levels of serum total cholesterol, triglycerides, and phospholipids between animals treated with PGF2 alpha and controls. Reduced concentrations of serum lipid levels and especially of HDL-cholesterol, HDL-triglycerides, and HDL-phospholipids were found in the rats treated with PGE1. These results suggest that PGF2 alpha and PGE1 could modify serum lipid levels influencing lipoprotein metabolism.

[Histological and histochemical observations on the horny pearls of pleomorphic adenoma]

An unusual case of pleomorphic adenoma displaying numerous horny pearls is described. The tumour arose in the right lateral lingual border of a 33-year-old man. In many pearls the cores were organized in two separate portions with distinct structural and histochemical features. The narrow peripheral portion had a compact structure and was rich in keratin since it contained cystine and was coloured with acid dyes of intermediate molecular size. The central portion was characterized by a loose texture and its histochemical profile (affinity for acid dyes of large molecular size, weak alcianophilia, vivid binding of colloidal iron) resulted from the existence of acidic mucosubstances in the cell coating of the neoplastic keratinized cells. These observations suggest that certain similarities exist between the processes of normal keratinization and squamous metaplasia in pleomorphic adenoma.

[An histologic and histochemical study of arteries in the stroma of oral squamous cell carcinoma]

A microscopical study of 175 oral squamous cell carcinomas demonstrated that 12% of the tumors showed small arteries in their stroma. The arteries occurred most frequently around the infiltrative border of the tumors. Focal intimal thickening was a common feature, while duplication of the internal elastic lamina or obliteration of the lumen appeared more rarely. The intimal thickenings consisted mainly of glycosaminoglycans, a fact supporting the hypothesis that they represented early atherosclerotic lesions. On the contrary, the duplication of the elastic lamina could be attributed to age-related changes. The complete closure of the lumen was brought about by a tissue rich in sulphated glycosaminoglycans; the uncertain pathogenetic mechanisms of endarteritis obliterans probably accounted for the development of this tissue.

Gingival manifestations of childhood cicatricial pemphigoid

Cicatricial pemphigoid (CP) is found almost exclusively among middle-aged and elderly persons. This article describes a rare case of CP in a 14-year-old girl; it appeared on the mandibular anterior gingiva as desquamative gingivitis. Histologic examination of the lesions showed a subepithelial bulla. Immunofluorescence of gingival biopsy revealed immunoglobulin G, protein C3, and faint immunoglobulin A deposition along the basement membrane zone; results for normal skin were negative. Indirect immunofluorescence produced negative results. There are only six documented cases of childhood CP previously reported in the literature. The clinical and immunologic features of these cases are reviewed.

Influence of prostaglandin E1 on high density lipoprotein-fraction lipid levels in rats

Serum lipid concentrations were determined in rats treated with PGE1 and in controls. Reduced concentrations of total lipids (P less than 0.001), cholesterol (P less than 0.001), triglycerides (P less than 0.05), and phospholipids (P less than 0.002) were found in the treated rats. Furthermore, decreased concentrations of HDL-cholesterol (P less than 0.001), HDL-triglycerides (P less than 0.02), and HDL-phospholipids (P less than 0.02) were observed in the treated rats. These lipid changes could be related to the antilipolytic action of PGE1. Furthermore, these results suggest that PGE1 may exert an antiatherogenic effect modifying serum lipid levels.