Ultrastrukturelle Acinusver�nderungen der Rattenparotis unter der Einwirkung von Antihypertensiva (Guanacline)

Experimental sialography: the effects of retrograde infusion of radiographic contrast media on salivary gland morphology and function. A review article

An experimental model for sialography, involving retrograde infusion of contrast medium into the rat submandibular gland under continuous pressure monitoring, was developed. Morphologic alterations induced during infusion of water- and lipid-soluble radiographic contrast media and the distribution of the media were examined with light and electron microscopy. An uneven distribution of the media throughout the tissue and variations in the degree of the alterations in different parts of the gland were seen at all stages of filling. The changes primarily consisted of dilation of the luminal system, which successively became more pronounced as infusion continued. Infusion of the lipid-based medium consistently resulted in more severe alterations, including changes in the acini. Tracer studies showed that the water-soluble medium leaked out through the intercellular spaces and to the surrounding tissue, whereas the lipid-based medium appeared to be confined to the luminal space. Ductal filling with either medium resulted in a relatively fast recovery; after prolonged infusion, recovery was slower and additional alterations occurred. The acini showed confluence of secretory granules and vacuole formation. After infusion of the lipid-based compound, autophagic vacuoles and granulomatous alterations developed. Prolonged infusion with either medium resulted in atrophy of the parenchyma and connective tissue proliferation in some glands. An inflammatory infiltrate was present in all glands during the recovery period. Functional alterations, primarily consisting of a decrease in flow rate, were noted after prolonged infusion. The increase in intraluminal pressure induced during infusion was most likely the primary cause of the alterations. In addition, the presence of contrast medium contributed to the long-term effects of the procedure.

A morphologic study of the recovery of the rat submandibular gland after retrograde infusion. II. Lipid-soluble radiographic contrast medium

Lipid-soluble radiographic contrast medium was infused retrogradely through the main excretory duct of the rat submandibular gland until ductal and slight parenchymal filling or heavy parenchymal filling was achieved, as determined by the developing intraglandular pressure. The glandular tissue was fixed by vascular perfusion at different times following infusion, and examined by light and electron microscopy. Dilation of the intralobular ducts and scalloping of the luminal border were pronounced after both degrees of filling. Widening of the acinar lumina and intercellular canaliculi occurred early. Masses of fused secretory granules were commonly seen in the cytoplasm of the acinar cells and formation of vacuoles occurred frequently. In some acinar cells, densely packed granules filled the major part of the cytoplasm. Large lysosomes and autophagic vacuoles, frequently present in the various parenchymal cells, often contained apparent contrast medium. In addition, widening of the intercellular spaces between parenchymal cells was seen, particularly in the acini and intercalated ducts. An inflammatory cell-infiltrate, primarily comprised of polymorphonuclear leukocytes, was particularly prominent at 20 h and 30 h after infusion. The changes were generally more pronounced and persisted for a longer time in glands subject to heavy parenchymal filling. Large cyst-like spaces surrounded by inflammatory cells were seen in the lobules and in the interlobular connective tissue of these glands. At later times, areas containing apparent contrast medium surrounded by macrophages, were frequently observed in the connective-tissue stroma. Atrophy of the parenchymal cells was seen later, after heavy parenchymal filling, and a proliferation of the connective tissue had occurred. The changes were most probably caused by the elevated intraglandular pressure induced during infusion, and the subsequent cell damage and inflammatory reaction. A foreign body reaction, induced by the retained lipid-soluble contrast medium, was probably partly responsible for the morphological alterations observed, following infusion.

Possible involvement of parotid beta-adrenergic receptors in the etiology of sialadenosis

The concentration of beta-adrenergic receptors was determined in rat and human parotid glands, in normal tissue as well as after sympathetic denervation of the rat, and in human sialadenosis. Receptor levels were clearly elevated after denervation of the rat and in sialadenosis. The possible implications of these findings for the etiology of human sialadenosis are discussed.

[The "stimulatory proteodyschylia" in the amitriptylin (Laroxyl) treated rat parotid gland. Experiments on the effect of antidepressive pharmacotherapy on the parotid glands of the rat (author's transl)]

The activity of total amylase and isoamylases in the rat parotid gland is reduced by treatment with Amitriptylin (Laroxyl) for 3 and 7 days while the protein content of the glands remains constant. These changes are no longer visible after treatment for 21 days and following a period without drug application. To differentiate the disturbances of protein secretion (proteodyschylia) prominent in the clinical picture of sialadenosis, the following classification is proposed. We suggest the term "stimulatory proteodyschylia" for a decrease of acinar amylolytic activity, here caused by Amitriptylin application, as opposed to the "inhibitory proteodyschylia" characterized by an acinar amylase congestion.

[Clinical aspects of non-tumorous diseases of the salivary glands]

The vast field encompassed by the non-tumorous diseases of the salivary glands poses difficult problems for their diagnosis and therapy. In order to facilitate comprehension of the pathological processes and the therapeutical possibilities for their treatment, physiological and biochemical aspects of salivary gland function are presented in the introduction. There are also mentioned in detail most of the diagnostic methods clinically applied today and stress is laid on their respective diagnostic values. In contrast to the opinion of many authors, exploratory excision and puncture are shown to be very important diagnostic tools in salivary gland pathology. The specific application of these methods is often the only means for a reliable diagnosis. The classification of the diseases follows Seifert's (1971) proposal. The chronic diseases of the salivary glands are specifically mentioned with the chronic recurrent and the chronic myoepithelial sialoadenitis taking first place. The sialoses are presented in a larger chapter. An attempt was made to correlate clinical and experimental results, to establish working hypotheses concerning the development of sialoses, to suggest therapeutical possibilities and, last not least, to give an idea of the many clinical and patho-anatomical difficulties to be overcome for a satisfactory understanding of such pathological processes. Finally, various forms of salivary gland fistulas and their treatment are mentioned. The long list of references merely gives an approximation of the abundance of publications dealing with the problems of this field.

Sialoadenosis produced by drug-treatment of hypertonicity. II. Experimental studies on the effects of guanethidine (Ismelin) on the submaxillary glands of the rat

48 rats were treated with guanethidine (Ismelin) in order to study the side-effects on the submaxillary glands following application of a routinely used antihypertensive substance. In contrast to guanethidine-treated parotid glands, no retention of alpha-amylase was observed. The amylolytic activities of the glands are decreased both after treatment for 24 hrs and when a 3 week treatment had been followed by a 2 week recuperation period. This decrease of total amylase content runs parallel with alterations in the alpha-isoamylase patterns of the submaxillary glands. Furthermore, gland growth is inhibited by the guanethidine-mediated "pharmacological sympathectomy". We interpret these proteodyschylic changes of the submaxillary glands as a pharmacologically induced peripheral neurogenic sialoadenosis.

[Sialoadenosis produced by drug-treatment of hypertonicity. I. Experimental studies on the effects of guanethidine (Ismelin) on the parotid glands of the rat (author's transl)]

48 rats were treated with the antihypertensive drug, guanethidine; its effects on the parotid glands (alpha-amylase content, protein concentration, and isamylase distribution patterns) were investigated. The treatment significantly increased the amylase activity in the gland extracts as well as the concentration of isoamylases and their specific enzyme activities. Moreover, we found a redistribution of activity between the 4 isoamylases of the parotid glands. The observed changes are the manifestations of a proteodyschylia concomitant with a peripheral neurogenic sialoadenosis. The described alterations are fully reversible within two weeks after discontinuation of the guanethidine application.

Ultrastructural studies of the parotid glands in sialadenosis

30 parotid biopsies of patients with sialadenosis--a symmetrical, painless, non-inflammatory, recurrent parotid swelling--were studied by electron microscopy. The patients suffered from different diseases, such as diabetes mellitus, liver diseases, hypertension and other affections. Parotid biopsies from 25 patients with slight parotitis or with oral cancer were used as controls. Morphometric studies reveal that the parotid swelling is caused by an enlargement of acinar cells. In controls the average diameters of the acinar cells are 30 to 40 mu. In sialadenosis the diameters are enlarged to 50 to 70 mu, in some cases to a maximum of 100 mu. Histologically the cytoplasm of the enlarged acinar cells shows either a granular pattern due to a numerical increase in secretory granules or a vacuolar transformation. Ultrastructurally the vacuolar transformed acinar cells also contain an increased number of granules with less electron density than the surrounding cytoplasm. Three types of sialadenosis can be distinguished with regard to the electron density of the acinar granules: a) a dark granular type, b) a pale granular type and c) a mixed granular type. The mixed granular type probably develops from the dark granular form. Alterations leading to the destruction of the myoepithelial cells were observed in all three types of sialadenosis with minimal changes in the dark granular type. Degenerative alterations of the autonomic nervous system are evident in all three groups with most pronounced changes in the pale granular type of sialadenosis. The ultrastructural alterations are interpreted as a disturbance of secretion, probably primarily caused by the degeneration of the autonomic nervous system. The alteration of the autonomic nervous system is suggested to be the common pathogenetic principle in all types of human sialadenosis occurring with different basic diseases. The enlargement of the acinar cells is the result of an intracellular disturbance in the secretory process due to the preceding defect of the autonomous nerval structures.

The effect of clonidine treatment on the salivary glands of the rat. Results of biochemical and histological investigations

The side-effects of clonidine, dryness of the mouth and parotid pain, as displayed by this clinically frequently used antihypertensive drug prompted us to investigate its effect on the salivary glands of the rat. After daily intraperitoneal injections for 3 weeks clonidine decreased the specific amylase content of the submaxillary glands caused by fall of activity in 2 of the 4 isoamylases. On the other hand, both activity of alpha-amylase and its isoenzyme pattern remained unchanged in the parotid glands as did their histological and histochemical appearance. The lymph nodes situated in front of the submaxillary glands, however, were considerably affected showing large abscesses. In the adjacent glandular parenchyma, round cell infiltrations and, occasionally, acinic cell necroses were observed.