Vascular Pattern Analysis on Microvascular Sonography for Differentiation of Pleomorphic Adenomas and Warthin Tumors of Salivary Glands

OBJECTIVES

Pleomorphic adenomas and Warthin tumors are the most common salivary gland tumors. It is important to differentiate between them because at least a partial parotidectomy is necessary for pleomorphic adenomas, whereas enucleation is sufficient for Warthin tumors. This study aimed to evaluate the usefulness of vascular pattern analysis using microvascular sonography to differentiate between the tumors.

METHODS

Sixty-two patients with pathologically proven pleomorphic adenomas (n = 38) and Warthin tumors (n = 24) were included. For all tumors, grayscale, power Doppler, and microvascular sonographic examinations were performed. Differences in vascular patterns (vascular distribution and internal vascularity) on power Doppler and microvascular sonography as well as grayscale sonographic features (size, shape, border, echogenicity, heterogeneity, and cystic change) between pleomorphic adenomas and Warthin tumors were evaluated. A comparison of diagnostic performances of grayscale sonography with power Doppler sonography and grayscale sonography with microvascular sonography was performed. The level of interobserver agreement between 2 reviewers in diagnosing tumors was evaluated.

RESULTS

No grayscale sonographic features showed a significant difference between the tumors. Vascular distributions and internal vascularity on power Doppler sonography (P = .01 and .002) and microvascular sonography (both P < .001) were all significantly different. The diagnostic accuracy of grayscale sonography with microvascular sonography (79.0%) was higher than that of grayscale sonography with power Doppler sonography (72.6%). This difference was significant according to the McNemar test (P = .004). Interobserver agreement was excellent in diagnosing tumors on both grayscale sonography with power Doppler sonography (κ = 0.83) and grayscale sonography with microvascular sonography (κ = 0.94).

CONCLUSIONS

Vascular pattern analysis using microvascular sonography with other sonographic features is helpful for differentiating between pleomorphic adenomas and Warthin tumors.

Spatial organization of the excretory ducts and sections of microcirculatory blood flow of the labial salivary glands in older adults

OBJECTIVE

Introduction: Salivary glands have a significant impact on the state of the homeostasis of the human body, oral cavity in particular, sensitively responding to pathological processes. The reactivity of the salivary glands in response to pathological processes that are organically linked to morphology and functions of the organ's structures, and particularly the excretory ducts of the glands and their microcirculatory blood flow, is one of the problems which have not been solved to date. The aim of the paper was to elucidate the features of the stereomicroscopic structure of the excretory ducts and sectors of the microcirculatory blood flow in labial glands of older adults.

PATIENTS AND METHODS

Materials and methods: The object of the study was the labial mucosa of the older adults, which was cut into 3х3 mm pieces and fixed in the buffered 4% glutaraldehyde solution with subsequent 2-hour fixation in osmium. Once the pieces were washed and dehydrated they were embedded into the Epon-812. The series of the semi-thin sections, made from the obtained epoxy blocks, were stained in phosphate buffered 0,1% toluidine blue solution. The serial semi-thin sections were subjected to histological and cytological studies and multilayered plastic reconstruction.

RESULTS

Results and conclusions: The series of histological epoxy semi-thin sections, as well as graphic and plastic reconstruction of the sectors of microcirculatory blood flow and excretory ducts of the human labial glands have demonstrated a range of morphological facts that can be used to clarify the intertissue stereological relationships. They also determined the syntopic proximity of the capacitive sectors of microcirculatory blood flow to the excretory ducts of the gland. Such pattern is especially notable in the collecting venules and intralobular ducts. It has been shown that the biggest venule is the collecting venous vessel. Anastomoses between the intralobular arterioles and collecting venules have been found in the microcirculatory blood flow of the labial glands.

An analysis of microvessel density in salivary gland tumours: a single centre study

BACKGROUNDS

Microvessel density (MVD) can be used for determining neoplastic neovascularisation. Tumour angiogenesis correlates with prognosis of cancers in many organs. The aims of this study were to evaluate MVD as demonstrated by CD31 and CD105 in salivary gland tumours (SGTs), and to correlate the MVD results with clinicopathological characteristics of the tumours.

MATERIALS AND METHODS

Using a retrospective cohort study design, we enrolled SGTs patients at the Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand, over the 22-year period. The predictor variables included demographic, anatomic and histopathological parameters. The outcome measure was average CD31-MVD and CD105-MVD counted by the "hot spot" method. Descriptive, uni- and bivariate statistics were computed, and P <0.05 was considered statistically significant.

RESULTS

The study sample consisted of 43 subjects with a mean age of 39.6 ± 17.8 years (range, 9-82), including 26 females (60.5%), diagnosed with SGTs. In this cohort, 58.1% of the cases were benign, and 83.7% were minor SGTs. There was a significant correlation between CD31-MVD and CD105-MVD (r = 0.8, P < 0.001), but mean CD31-MVD and CD105-MVD were 17.7 ± 9.3 and 12.8 ± 7.4, respectively (P = 0.009). Age, gender and tumour site were not individually associated with significant differences between CD31-MVD and CD105-MVD. Tumours with myoepithelial cells had lower MVD than those without myoepithelial cells (P = 0.04 for CD31; P = 0.03 for CD105). Only CD105-MVD showed statistical difference between benign and malignant SGTs (P = 0.01).

CONCLUSIONS

These results suggest that MVD in SGTs can be demonstrated by CD31 and CD105. Despite a strong correlation, CD31-MVD is always higher than CD105-MVD and cannot differentiate between benign and malignant SGTs. The presence of myoepithelial cells within SGTs affects the MVD analysis using either CD31 or CD105, while age, gender and tumour location do not.

[Cone beam 3D sialography: preliminary study]

INTRODUCTION

Stones, stenosis and inflammatory lesions are the main causes of mealtime syndrome. The aim of paraclinical exam is to find the cause of these obstructive symptoms. Ultrasound is often sufficient to confirm the lithiasic origin of salivary gland swelling. Non-lithiasic salivary obstructions are more difficult to diagnose. We studied the feasibility and quality of a new medical imaging device: three-dimensional (3D) sialography using the technique of cone beam with flat panel (CPCT).

PATIENTS AND METHODS

Five patients were included, referred for diagnostic management of non-lithiasic salivary gland parotid colic. It was performed for each patient in the angiography room, conventional sialography and 3D CPCT. Images were compared to conventional sialography.

RESULTS

None of catheterization failure or side effects were observed in five patients. 3D CPCT sialography enabled to view gland ducts until their fifth or sixth division. Compared to conventional sialography, 3D CPCT improves signal and contrast to noise ratio.

DISCUSSION

This technique allows an anatomic resolution and signal/noise ratio unmatched. It also allows to reduce metallics artefacts. Its main drawback is those associated with ductal catheterization, exposure to ionizing radiation and potential allergy to iodinated contrast agents.

Functional activity of rabbit salivary glands in reduced and restored regional arterial blood supply conditions

BACKGROUND

Although the vascular pathology of carotid arteries is widespread, the function of salivary glands in reduced arterial flow conditions is not much investigated clinically and in experiments. At the same time blood supply is a keystone to normal functioning of every organ and especially of salivary secretion. The aim of this study was to estimate functional activity of salivary glands in reduced and restored blood supply conditions in experiment by sialoscintigraphy which is an approved method for functional assessment of salivary glands.

METHODS

The ligature of a. carotis communis dextra was performed on 20 Californian rabbits. After 28 days sialoscintigraphy with Tc99 pertechnetate and revascularization through resection of the occluded part of a. carotis communis and reconstruction with venous autograft was performed. One month later sialoscintigraphy was done.

RESULTS

The functional activity of rabbit salivary glands after the ligature of a. carotis communis is strongly depressed. The revascularized glands accumulated isotope slowly, but the level of accumulation was higher than on the control side.

CONCLUSION

The ligature and reconstruction of a common carotid artery on rabbits confirm the important role of the arterial blood supply in functional activity of salivary glands and may be an appropriate experimental model for investigation of ischemic disease of salivary glands.

Vascular endothelial growth factor expression (VEGF) in salivary glands of diabetic rats

This study is aimed at evaluating vascular endothelial growth factor (VEGF) expression in the salivary glands of diabetic rats. Our study was carried out on 1 group of male Wistar rats and 1 group of male Bio Breeding Wistar (BB/W) pre-diabetic rats. The first group (control) was composed of 11 rats (4 months old), and the other (test) of 11 rats (4 months old) which showed diabetes at day 85 of life. This kind of diabetes can be compared to human diabetes mellitus type 1. The submandibular glands were removed and processed for immunohistochemical analysis of VEGF. Diabetes increased salivary gland VEGF expression in the rats. The tissues analyzed (vascular endothelium, ductal endothelium, mucinous glands) always expressed VEGF, thus demonstrating that not only vascular endothelial cells, but also the other elements evaluated, have a role in the neoangiogenesis process. In both control and diabetic rats, the VEGF expression was constantly negative only in serous acini; thus demonstrating that serous acini are not involved in the neoangiogenetic processes. The vascular growth is a fundamental part of normal salivary gland development, therefore we speculate that strategies aimed at preservation or promotion of salivary gland VEGF expression may mitigate or attenuate diabetic-induced gland microvascular injury.

Prevention of Irradiation-induced Salivary Hypofunction by Microvessel Protection in Mouse Salivary Glands

Treatment of most head and neck cancers includes radiotherapy. Salivary glands (SGs) in the irradiation (IR) field are irreversibly damaged resulting in severe hyposalivation. We evaluated the importance of SG endothelial cells to this IR-induced injury, and whether serotype 5 adenoviral (Ad5) vector-mediated transfer of basic fibroblast growth factor (AdbFGF) or vascular endothelial growth factor (AdVEGF) complementary DNAs would afford radioprotection. Four hours after IR, microvessel density (MVD) in SGs decreased by approximately 45%. However, if mice were pre-treated with either AdVEGF or AdbFGF 48 hours before IR the loss in MVD was significantly reduced. An irrelevant vector, AdLacZ, encoding Escherichia coli beta-galactosidase, was without effect. After 8 weeks, IR reduced salivary flow by approximately 65% in untreated mice. Mice pre-treated (using 5 x 10(9) particles/gland 48 hours prior to IR) with AdLacZ exhibited a reduction in salivary flow similar to untreated mice receiving IR. However, irradiated mice pre-treated with AdbFGF or AdVEGF showed a significant improvement in their salivary flow, to approximately 70% (P < 0.01) and 80% (P < 0.01), respectively, compared to non-irradiated control mice. These results are consistent with the notion that injury to the adjacent microvasculature may play an important role in SG radiation damage. Furthermore, our results suggest that a local transient treatment directed at protecting SG endothelial cells may be beneficial for patients undergoing IR for head and neck cancer.

Decrease of mosquito salivary gland proteins after a blood meal: an implication for pathogenesis of mosquito bite allergy

Salivary gland protein profiles ofAedes aegypti (L.) and Culex quinquefasciatus (Say) pre- and post-blood feeding were analyzed. SDS-PAGE studies before blood feeding of Ae. aegypti demonstrated 8 major polypeptide bands of 20, 35, 37, 42, 45, 47, 70 kDa and a high molecular weight band >118 kDa, whereas those of Cx. quinquefasciatus demonstrated 9 major polypeptide bands of 20, 26, 36, 38, 45, 47, 49 kDa and 2 high molecular weight bands >118 kDa. After a blood feeding, salivary gland polypeptides of Ae. aegypti at 35, 37, 45, 47, 70 kDa and high molecular weight band >118 kDa were depleted, while the polypeptide bands of 20, 26, 36, 38 kDa were depleted in Cx. quinquefasciatus. The presented study suggests that these major polypeptides were introduced into vertebrate hosts when a mosquito took a blood meal. Further investigation in molecular, biochemical and immunological aspects of these salivary gland polypeptides may provide information for better understanding in the role of these proteins in mosquito bite allergy.

Sialorrhea: a review of a vexing, often unrecognized sign of oropharyngeal and esophageal disease

Saliva is produced by the major salivary glands (parotid, submandibular, and sublingual), as well as several smaller glands. Salivary flow can be altered by multiple entities. There is much written regarding xerostomia ("dry mouth"), the condition related to inhibited or decreased salivary flow. This condition is widely recognized in certain systemic diseases, particularly Sjögren syndrome, diabetes mellitus, after anticholinergic, antihistamine, and decongestant medications, as well as states of enhanced sympathetic drive, such as anxiety or emotional disturbances and various other psychosocial conditions. On the other hand, sialorrhea or ptyalism, the condition of increased salivary flow, is rarely discussed in the clinical literature. Sialorrhea can occur with various neurologic disorders, infections, the secretory phase of the menstrual cycle, heavy metal poisoning, Wilson disease, Angelman syndrome, as well as a relatively unknown condition called idiopathic paroxysmal sialorrhea. Normal salivation may be altered by drugs (such as clozapine, risperidone, nitrazepam, lithium, and bethanecol) that have a cholinergic effect that induces sialorrhea. This report focuses on sialorrhea as it relates to disorders of the oropharynx and esophagus. The patient typically recognizes a problem with excessive "foamy mucus" but does not understand its origin. Infections and obstruction are the most common oropharyngeal causes. Increased salivary flow occurs as a typically subtle manifestation of gastroesophageal reflux disease. This occurrence is referred to as water brash. Idiopathic achalasia and megaesophagus due to the parasite Trypanosoma cruzi are regularly associated with sialorrhea. Esophageal obstruction (foreign body, cancer, or stricture formation), infection, and nasogastric intubation are the more common conditions associated with the symptomatic sequelae of sialorrhea. Sialorrhea-related respiratory and pulmonary complications are greatest in those with a diminished sensation of salivary flow and hypopharyngeal retention. Extremes of age, the chronically debilitated, or those in chronic care facilities, especially associated with cerebrovascular accidents and esophageal cancer, typically comprise this population. For the patient with an intact awareness of saliva, sialorrhea can present with significant social stigmas. Occult drooling or regular oral evacuation into a tissue or "spit cup" is socially incapacitating. This report provides a review of the physiology, pathogenesis, clinical manifestations, and therapeutic options for sialorrhea. Physicians and other healthcare professionals should recognize the importance of sialorrhea as a possible indicator or complication of a variety of disease states of the oropharynx and esophagus as well as its impact on the patient's physical and social quality of life.

Analysis of salivary gland proteins of the mosquito Armigeres subalbatus

Quantitative studies of total salivary gland protein of Armigeres subalbatus mosquito revealed that the total salivary gland protein increased dramatically during the five days after emergence as adults. The amount of salivary gland protein of female and male mosquitos at day five after adult emergence were on the average 11.55 and 1.32 microg/pair gland respectively. SDS-PAGE studies showed that salivary gland protein profiles of Armigeres subalbatus demonstrated 9 major polypeptide bands of 68, 65, 60, 55, 40, 30, 28, 21, and 15 kDa. The 21 and 65 kDa bands were found only in the distal lateral region of the mosquito salivary gland and were depleted after the female mosquito took a blood meal.

Dermatomyositis associated with Sjögren's syndrome: VEGF involvement in vasculitis

Two patients with dermatomyositis complicated with Sjögren's syndrome (SjS), are reported. Both patients exhibited sensory-dominant polyneuropathy, compatible with neurologic involvement in SjS. Vascular endothelial growth factor (VEGF) levels were increased in their plasma. Histological examination demonstrated vasculitic changes in biopsied specimens of muscle and salivary glands from the patients, and VEGF was overexpressed in the vasculitic lesions. These findings suggest that VEGF overexpression was associated with the development of vasculopathy in skeletal muscle and salivary glands and possibly in the peripheral nervous system.

Central moxonidine on salivary gland blood flow and cardiovascular responses to pilocarpine

Peripheral treatment with the cholinergic agonist pilocarpine induces intense salivation that is inhibited by central injections of the alpha2-adrenergic/imidazoline receptor agonist moxonidine. Salivary gland blood flow controlled by sympathetic and parasympathetic systems may affect salivation. We investigated the changes in mean arterial pressure (MAP) and in the vascular resistance in the submandibular/sublingual gland (SSG) artery, superior mesenteric (SM) artery and low abdominal aorta (hindlimb) in rats treated with intraperitoneal (i.p.) pilocarpine alone or combined with intracerebroventricular (i.c.v.) moxonidine. Male Holtzman rats with stainless steel cannula implanted into lateral ventricle (LV) and anesthetized with urethane were used. Pilocarpine (4 micromol/kg of body weight) i.p. reduced SSG vascular resistance (-50+/-13% vs. vehicle: 5+/-3%). Pilocarpine i.p. also increased mesenteric vascular resistance (15+/-5% vs. vehicle: 2+/-3%) and MAP (16+/-3 mmHg, vs. vehicle: 2+/-3 mmHg). Moxonidine (20 nmol) i.c.v. increased SSG vascular resistance (88+/-12% vs. vehicle: 7+/-4%). When injected 15 min following i.c.v. moxonidine, pilocarpine i.p. produced no change on SSG vascular resistance. Pilocarpine-induced pressor responses and increase in mesenteric vascular resistance were not modified by i.c.v. moxonidine. The treatments produced no change in heart rate (HR) and hindlimb vascular resistance. The results show that (1) i.p. pilocarpine increases mesenteric vascular resistance and MAP and reduces salivary gland vascular resistance and (2) central moxonidine increases salivary gland vascular resistance and impairs pilocarpine-induced salivary gland vasodilatation. Therefore, the increase in salivary gland vascular resistance may play a role in the anti-salivatory response to central moxonidine.

Ultrasonography and colour doppler sonography of salivary glands in primary Sjögren's syndrome

To examine either the ultrasonographic (US) features of the parotids and submandibular glands or the blood flow alterations that may occur in the salivary glands of patients with primary Sjögren's syndrome (pSS) we studied 30 female patients with pSS and 30 controls suffering from dry mouth not due to pSS. All measurements were taken by the same examiner, who used the same equipment to avoid interobserver variability. The US parameters recorded (parenchymal homogeneity, echogenicity, size of the glands and posterior glandular border) were scored according to a previously described scoring system. For each waveform, peak systolic velocity (PSV) and resistive index (RI) were measured at the external carotid artery in the examination of the parotids and at the facial artery within the submandibular glands before and during lemon juice stimulation. On the basis of the degree of chronic inflammatory changes at minor salivary gland (MSG) biopsy, chronic sialadenitis (CS) was defined as mild in 10 and severe in 20 pSS patients. Abnormal US scores were obtained in 26/30 (86.6%) pSS patients and in 9/30 (30%) controls. Moreover, in pSS patients the US scores were sigificantly higher than in the control group (p=-0.0001). The mean (+/- SD) difference between the PSV values taken from parotids and submandibular glands before and during lemon juice stimulation was statistically significant (p=0.003 and p=0.01, respectively) in the controls. On the other hand, no significant changes in the PSV values were found in the whole group of pSS patients. However, the changes in PSV values before and during lemon juice stimulation were statistically significant in both parotids (p=0.019) and submandibular glands (p=0.012), and not significantly different from those in the controls in pSS patients with mild CS. The variability of RI taken from the salivary glands before and during lemon juice stimulation was not statistically significant in either pSS patients or controls. US abnormalities were detected in the majority of pSS patients and their severity was significantly greater than those recorded in the controls. Of the colour Doppler sonographic (CDS) parameters only PSV was influenced by the degree of chronic inflammation, as shown at the MSG biopsy, suggesting that PSV may reflect the vascular changes occurring in the salivary glands during the course of an autoimmune disease such as pSS.

The expression of E-cadherin-catenin complex in adenoid cystic carcinoma of salivary glands

OBJECTIVE

The aim of this study was to investigate the expression of the E-cadherin-catenin (E-cad-cat) complex in human salivary adenoid cystic carcinoma (ACC) and determine the effects of E-cad-cat expression on tumor differentiation, metastasis, and invasion, as well as its clinical significance.

METHODS

The expression of adhesion molecules, which included E-cadherin, alpha-catenin, and beta-catenin, on 10 cases of normal salivary glands, and 50 cases of human salivary ACC were investigated by immunohistochemistry.

RESULTS

Strong and stable expression of E-cad-cat complex showed in normal salivary glands tissues. However, weaker expression and even complete absence, of the positive signals were shown on all ACC cases. Coexpression of E-cad-cat were detected in 29 (58%) of the 50 ACC specimens. Positive staining of E-cad-cat complex were detected in 7 (39%) of the 18 ACC primary sites that had aggressive phenotype of nerve and vasculature.

CONCLUSION

Strong positive signals of E-cad-cat complex are shown in normal salivary glands, and the down-regulated expression were observed in ACC cases. The expression of E-cad-cat complex is associated with a more aggressive phenotype on nerve and vasculature. No association with various histopathologic subtypes was found. However, absent or low E-cad expression was observed more frequently in solid carcinomas than in cribriform or tubular carcinomas. Down-regulation of E-cad-cat complex may be associated with canceration of normal salivary glands. The expression levels of E-cad-cat were positively correlated to the differentiation of ACC tumor cells.

Tissue effects of salivary gland fine-needle aspiration. Does this procedure preclude accurate histologic diagnosis?

Recent reports have alluded to various tissue effects secondary to fine-needle aspiration (FNA), particularly infarction observed in resected salivary gland masses, precluding accurate histologic diagnosis. Our experience with the use of 25-gauge needles indicates otherwise. We retrospectively reviewed 94 resected salivary gland masses previously sampled by FNA, looking for infarction, hemorrhage, needle track tumor seeding, and fibrosis. We assessed the significance of these complications and their impact on the histologic diagnosis. The median interval from FNA to excision was 25 days. Variable degrees of infarction and hemorrhage were present in 7 cases (7%) and 9 cases (10%), respectively. Infarction ranged from 5% to 80% (average, 20%), while hemorrhage averaged less than 20% of the material on the tissue sections. Significant infarction was present in acinic cell carcinomas (3/7), but histologic diagnosis was not compromised, and tissue alterations were absent. We conclude that FNA of salivary gland lesions using 25-gauge needles is safe and does not significantly alter the histologic diagnosis. The tissue effects observed did not preclude accurate diagnostic interpretation in any case.

Sympathetic and parasympathetic interaction in vascular and secretory control of salivary glands in anaesthetised dogs

The present study was undertaken to examine sympathetic-parasympathetic interactions in the regulation of salivary gland function, with special reference to the possible role of the sympathetic cotransmitter neuropeptide Y (NPY). In dogs anaesthetised with pentobarbitone, electrical stimulation of the parasympathetic nerve to the submandibular gland evoked an increase in glandular blood flow and salivary secretion. Sympathetic nerve stimulation evoked a significant prolonged attenuation of vasodilator and secretory responses to subsequent parasympathetic stimulation. This attenuation was not significantly altered by alpha- and beta-adrenoceptor blockade. Systemic administration of the sympathetic cotransmitter, NPY, mimicked the effect of the sympathetic stimulation by significantly attenuating vasodilatation and salivary secretion. The NPY Y1 receptor agonist, [Leu31, Pro34]NPY and the specific NPY Y2 receptor agonist N-acetyl[Leu28, Leu31]NPY 24-36 both significantly attenuated the vasodilatation and salivary secretion evoked by stimulation of the parasympathetic nerve. The NPY Y1 receptor antagonist, GR231118 significantly antagonised the attenuation of vasodilatation caused by both sympathetic stimulation and the NPY Y1 receptor agonist. GR231118 also inhibited the pressor response of NPY. Intra-arterial injection of methacholine and stimulation of the parasympathetic nerve both caused local vasodilatation in the gland which was significantly attenuated by pretreatment with sympathetic stimulation or the NPY Y1 agonist. The NPY Y2-specific agonist did not attenuate methacholine-induced vasodilatation but did attenuate vasodilatation evoked by parasympathetic stimulation. The results indicate that NPY as a sympathetic cotransmitter may have a role in the regulation of vascular secretory function of salivary glands.

Are myoepithelial cells responsible for the widespread expression of inducible nitric oxide synthase in pleomorphic adenoma? An immunohistochemical study

Many of the actions of nitric oxide (NO) are still poorly understood. Recently, it has been shown that the inducible isoform of the enzyme nitric oxide synthase, iNOS, is expressed in both salivary ducts and pleomorphic adenoma. The current immunohistochemistry study determined whether or not this distribution correlated with smooth muscle actin (SMA) expression, thereby suggesting the expression by myoepithelial cells in both sites. Twenty cases of histologically confirmed pleomorphic adenoma, the sections of which contained adjacent normal salivary gland tissue, were stained for iNOS and smooth muscle actin (clone 1A4). The salivary ducts of all cases were stained intensely by both antibodies, with smooth muscle actin staining also being noted around acini in the normal gland parenchyma. Moderate or heavy staining for iNOS was found in all specimens of pleomorphic adenoma, with smooth muscle actin being distributed in a similar manner in 19 cases. Smooth muscle actin, but not iNOS, was also noted in blood vessels of both normal glands and tumours. The correlation between iNOS and SMA in pleomorphic adenoma was significant (P<0.001). The presence of iNOS in normal salivary ducts and pleomorphic adenoma is most likely due to expression by myoepithelial cells.

Mycophenolate mofetil ameliorates perivascular T lymphocyte inflammation and reduces the double-negative T cell population in SLE-prone MRLlpr/lpr mice

Effects on T lymphocyte mediated pathology, phenotypes, and functions in MRLlpr/lpr mice given mycophenolate mofetil (MMF) (100 mg/kg/day) via drinking water or controls given ip cyclophosphamide (CYC) injections (1.8 mg/mouse/week) or water were described. Both MMF and CYC treatment diminished kidney and large salivary gland perivascular cell infiltrates, reduced profoundly double-negative (DN) T cell frequencies, decreased total lymphocyte number in spleen, and increased in vitro proliferative response to Con A. IFN-gamma and IL-10 in supernatants from Con A stimulated spleen cells were augmented after MMF but not CYC treatment. MMF treatment increased whereas CYC reduced IL-12 in serum. Kidney expressions of IFN-gamma, IL-10, and IL-12 mRNA were unaffected by MMF but decreased by CYC. Our results demonstrate that MMF and CYC suppress perivascular T lymphocyte inflammation by reducing the DN T cell population and by amelioration of T cell function. The varying cytokine patterns suggest different mechanisms of the two drugs.

[The application of color Doppler ultrasound technique in diagnosing the lumps of salivary gland]

OBJECTIVE

To evaluate the value of color doppler ultrasound technique in diagnosing the lumps of salivary gland.

METHODS

233 cases of salivary gland lumps were examined with color doppler high frequency ultrusound technique. Among them were, 189 cases benign and the others malignant.

RESULTS

Color doppler ultrasound technique could not only show the morphology, structure, sizc, location and adjoining relationship, but also indicate the pathological classification according to the blood supply. The total coincident rate of this ultrasound diagnosis to the pathological one was 89.3%.

CONCLUSION

Color doppler ultrasound technique is a simple and harmless diagnosing method and could preoperatively give a reliable information to the decision of surgical plan.

Immunohistochemical findings of arterial fibrinoid necrosis in major and lingual minor salivary glands of primary Sjögren's syndrome

Arterial fibrinoid lesions in major salivary glands and lingual minor salivary glands from four autopsied patients with primary Sjögren's syndrome were studied histologically and immunohistochemically. On a morphological basis, the preceding arterial fibrinoid necrosis was regarded as medial damage, particularly of smooth muscle cells. The medial smooth muscle cells underwent vacuolated degeneration and disappeared, and resulted in full-blown fibrinoid arteritis. By means of the immunoperoxidase method the distribution of the immunoglobulins, fibrin, complement (C3), transferrin, ferritin, vimentin and lysozyme was studied. The normal arterial wall reacted with the lambda light chain of immunoglobulin, transferrin and vimentin Vacuolated degeneration of medial smooth muscle cells, regarded as the initial change in cases of vascular fibrinoid lesion, was positive for IgG, C3 and vimentin. We suggest that IgG antibody is a useful marker to detect the initial phase of arterial fibrinoid necrosis. In the foci of fibrinoid necrosis, fibrin, C3 and vimentin were detected. Among these three antibodies, only fibrin was negative in the normal arterial wall and vacuolated degenerates of medial smooth muscle cells. Mononuclear cells surrounding areas of fibrinoid necrosis stained strongly with antisera to immunoglobulins, transferrin, ferritin and vimentin, and negatively with fibrin, C3 and lysozyme antibodies.

Different La/SS-B mRNA isoforms are expressed in salivary gland tissue of patients with primary Sjögren's syndrome

Recently we isolated a La/SS-B mRNA isoform from a cDNA library made from peripheral blood lymphocytes of a patient with primary Sjögren's Syndrome. In the La/SS-B mRNA isoform the exon 1 was replaced. The alternative exon was termed exon 1'. Genomic analysis showed that the exon 1' La mRNA was the result of a promoter-switch in combination with alternative splicing. Due to the unusual structure of the exon 1' La/SS-B mRNA, the function and the behaviour under physiological and pathophysiological conditions in tissue of patients with primary Sjögren's syndrome or Systemic Lupus Erythematosus remained obscure. Therefore assays were established allowing a qualitative and quantitative estimation of expression of the exon 1 and 1' La mRNA form, including in situ and dot blot hybridization as well as reversed PCR. Both mRNA forms were found to represent finally processed cytoplasmic mRNAs belonging to the abundant class of mRNAs. They were expressed and regulated in parallel. A ratio exon 1 to 1' between 1:1 and 5:1 was determined. Both mRNA forms were downregulated in quiescent cells and upregulated in activated and proliferating cells including non-keratized stratified squamous epithelial, endothelial, salivary gland as well as infiltrating cells.

Vascular changes in major and lingual minor salivary glands in primary Sjögren's syndrome

A histological investigation of the vascular changes of three major and lingual minor salivary glands in primary Sjögren's syndrome was carried out on eight autopsied Japanese patients. This study compares vascular lesions in salivary glands between one group of four short-term corticosteroid-treated patients (Cases 1, 3, 4 and 7) and the other group of four long-term corticosteroid-treated patients (Cases 2, 5, 6 and 8). We proposed the following five stages for morphogenesis of arteritis; (1) endothelial swelling, (2) thrombosis, (3) fibrinoid degeneration, (4) necrotizing panarteritis and (5) endarteritis obliterans. Endothelial swelling was seen in small-to-large arteries of major salivary glands and the tongue, and this finding was considered as the initial change of vascular lesion. Thrombosis was observed in the small arteries of both organs. Fibrinoid degeneration and necrotizing panarteritis were predominantly localized in small and middle-sized arteries. Endarteritis obliterans was observed in small and large arteries of major and lingual minor salivary glands in primary Sjögren's syndrome. Vascular lesion of this type was common in the four patients who received corticosteroid for more than 12 months. Corticosteroid therapy appears to accelerate the fibrotic change of the vascular wall. Therefore, we suggest that essential vascular lesions of major and lingual minor salivary glands in primary Sjögren's syndrome may include four types (endothelial swelling, thrombosis, fibrinoid degeneration and necrotizing panarteritis), excluding endarteritis obliterans.

Color Doppler sonography of salivary glands

OBJECTIVE

We used color Doppler sonography to evaluate the vascular anatomy of the salivary glands and to analyze physiologic changes that occur during salivary stimulation in normal subjects and the flow alterations that occur in diseased glands.

SUBJECTS AND METHODS

The vascular appearance of the three major salivary glands was examined in healthy volunteers (n = 24); in patients with chronic autoimmune diseases, including Sjögren's syndrome (n = 23) and salivary sarcoidosis (n = 2); and in a variety of benign (n = 49) and malignant (n = 13) nodules. Physiologic changes were assessed in healthy volunteers by means of a stimulation test with lemon and were quantified with color images and spectral analysis. Tumor vascularity was graded on a four-step analog scale of 0 to (+3) and classified as either peripheral or hilar, depending on the distribution of vessels.

RESULTS

In the control subjects, color Doppler imaging accurately reflected the complex vascular anatomy of the salivary glands and showed dramatic changes occurring in parenchymal vessels during lemon stimulation as a result of the intense hyperemia associated with the secretion of saliva. Sjögren's syndrome and sarcoidosis showed a diffuse hypervascular pattern when morphologic changes of salivary parenchyma were seen on gray-scale sonograms. Benign tumors showed a lower grade of vascularity than did malignant tumors. All but one of the hypovascular nodules graded as 0 (n = 8) and + (n = 23) were benign. Conversely, eight of 11 nodules labeled with the highest grade of tumor vascularity (+3) were malignant. When the pattern of tumor flow signals was peripheral, it could be considered specific enough to aid in diagnosing pleomorphic adenoma. Peak systolic velocities greater than 60 cm/sec were never detected in benign tumors and were seen in only 44% of malignant tumors.

CONCLUSION

Color Doppler sonography is a promising technique for analyzing the vascularity of the salivary glands and for characterizing some pathologic conditions. Our experience suggests that color Doppler sonography can provide additional diagnostic information in patients with chronic inflammatory diseases or suspected malignant tumors and can help in differentiating pleomorphic adenomas from other salivary gland tumors.

Characterization of binding sites and effects of calcitonin gene-related peptide (CGRP) and CGRP 8-37 on regional blood flow in rabbit salivary glands

Calcitonin gene-related peptide (CGRP) is a neuropeptide present in nerve fibres of salivary glands in several species, including man. One of the major targets of these nerve fibres are blood vessels of the glands. The presence and distribution of specific binding sites for CGRP in the rabbit major salivary glands was here investigated autoradiographically. In order to determine the physiological role of CGRP, regional blood flow was measured after intravenous (i.v.) or intra-arterial (i.a.) administration of CGRP or the antagonist CGRP 8-37, using a microsphere technique. Specific binding sites for CGRP were found in the parotid, submandibular and sublingual glands, distributed mainly in the muscular and endothelial layers of the blood vessel walls. CGRP injected i.a. (10 pmol/kg) caused a significant increase in regional blood flow in all major salivary glands. However, i.v. infusion of CGRP (120 pmol/kg) decreased regional blood flow in the parotid and sublingual glands, due to a general decrease in peripheral resistance and redistribution of peripheral blood flow. CGRP 8-37 given i.a. together with CGRP significantly inhibited the blood-flow increase by CGRP alone. It is concluded that most of the CGRP receptors in the rabbit salivary glands are localized in vascular elements. The physiological data show that CGRP acts as a vasodilator in the major salivary glands of the rabbit in vivo, and that the effect of CGRP is inhibited by the CGRP antagonist CGRP 8-37.

Rat salivary gland blood flow and blood-to-tissue partition coefficients following X-irradiation

Effects of a single high dose of X-irradiation (15 Gy) to the head and neck region in adult male rats were examined. Three days after radiation, rats were infused with [14C]-iodoantipyrine (IAP) via the femoral vein. Animals were killed at designated times thereafter and the three major salivary glands removed. The uptake of IAP by these tissues was analysed using a pharmacokinetic model. Radiation had relatively modest effects on all measured variables when compared with results from the non-irradiated control and pair-fed groups.

[Usefulness of color Doppler flow imaging for blood flow in salivary gland]

We investigated the arterial and venous blood flow response in submandibular gland to secretory stimulation using color doppler flow imaging in six normal subjects. During examination secretory stimulation by lemon juice was used. The arterial and venous flow markedly increased after secretory stimulation in all normal subject. It was seemed to be that color doppler flow imaging was of value in evaluation of the blood flow in salivary gland.

Changes in the lectin-binding of capillaries in rat salivary glands after streptozotocin-induced diabetes

The lectin-horseradish peroxidase conjugate of GSA I-B4 (Griffonia simplicifolia isolectin) has some binding affinity with capillary walls in sections of the major salivary glands from normal rats. After inducing diabetes with streptozotocin a conspicuous increase in the staining intensity with GSA I-B4 was already evident in parotid capillaries at 3 weeks and this increase persisted at 3 and 6 months. In submandibular capillaries, however, an increased uptake of GSA I-B4 was evident only at 6 months after inducing diabetes. The reasons for these different time scales in the two glands are not known but the increased uptake of GSA I-B4, which is due to an increase in carbohydrate-containing sites with available terminal alpha-D-galactose, is considered to reflect a pathological change.

Necrotizing sialometaplasia. A clinicopathologic study of sixty-nine cases and review of the literature

The clinicopathologic findings in 69 cases of necrotizing sialometaplasia (NS) were analyzed and compared with 115 reported cases of NS in the English-language literature. Data comparing age, sex, race, location, clinical presentation, and possible predisposing factors are summarized. Analysis of the data indicates that NS can occur in a variety of clinical settings and may exhibit a spectrum of histologic features. Recognition of NS, regardless of its clinical or microscopic presentation, is essential to avoid inappropriate or unnecessary treatment for this benign reactive process.

Salivary gland disease in dogs and cats: 245 cases (1985-1988)

Diagnostic pathology records spanning 41 months (July 1985 through November 1988) were searched for diagnoses of salivary gland disease in dogs and cats. Review of 87,392 records from that period revealed 245 cases (0.3%) in which salivary gland tissue had been evaluated. During that period, salivary gland tissue was submitted to the laboratory almost twice as often from dogs (160 cases) as from cats (85 cases). On the basis of histologic examination, 89% of salivary gland submissions from small animal practices were allotted to 1 of 5 major categories: malignant neoplasms (30%; 74/245), sialadenitis (26%; 64/245), normal salivary gland (16%; 40/245), sialocele (9%; 21/245), and salivary gland infarction (8%; 20/245). The remaining 11% of submissions included various degenerative or fibrotic lesions, ductal ectasia, sialolithiasis, edema, benign neoplasia, and secondary salivary involvement with systemic or cervical lymphosarcoma or with fibrosarcoma in the head and neck.

Morphometric study of the microvasculature of the main excretory duct subepithelia of the rat parotid, submandibular and sublingual salivary glands

This study investigated the relationship between the fine structure of the main excretory duct (MED) epithelia and the subepithelial capillaries of the major salivary glands (parotid, submandibular, and sublingual) in the rat. The MED subepithelial capillaries vary in type (fenestrated and continuous), number of fenestrae present in the available fenestrated endothelium (the attenuated area of endothelium), and number of capillaries per unit length of epithelium. In the parotid gland, continuous capillaries predominate, and the capillary density per 200 microns of epithelium (1.73 in region I and 1.03 in region II) is lower than in the other two glands, as is the number of fenestrae per 10 microns of available endothelium (1.97 in region I and 1.25 in region II). The submandibular gland has mainly fenestrated capillaries. The capillary density per 200 microns of epithelium (4.46 in region I and 5.51 in region II) is higher than in the other two glands, as is the number of fenestrae per 10 microns of available endothelium (4.82 in region I and 7.90 in region II). Similarly, in the sublingual gland, fenestrated capillaries are dominant. The density of capillaries per 200 microns of epithelium (4.15 in region I and 4.31 in region II) is intermediate between the parotid and submandibular glands, as is the number of fenestrae per 10 microns of available endothelium (2.98 in region I and 3.83 in region II).

Non-adrenergic sympathetic vasoconstriction in the eye and some other facial tissues in the rabbit

The effects of unilateral sympathetic nerve stimulation (SNS) on regional blood flow in the rabbit were studied with radioactive microspheres. SNS at 10 or 4 Hz caused an approximately 60% reduction in choroidal blood flow, which was partly resistant to alpha-adrenoceptor blockade with phenoxybenzamine. The vasoconstriction evoked by SNS at 2 Hz was completely abolished by alpha-adrenoceptor blockade. A similar response was seen in the iris, ciliary body, masseter muscle and lacrimal gland. In the harderian gland, however, SNS (2 Hz) after alpha-adrenoceptor blockade caused a significant reduction in blood flow. In the salivary glands, combined beta- and alpha-adrenoceptor blockade with propranolol and phenoxybenzamine revealed a slight non-adrenergic vasoconstriction during SNS at 10 Hz; however, the blood flow was significantly increased during SNS at 4 and 2 Hz following alpha-adrenoceptor blockade. These results indicate that there is a frequency-dependent, non-adrenergic component in the sympathetic vasoconstriction of the eye and several facial tissues. In the salivary glands, beta-adrenoceptor-mediated vasodilatation tends to mask a non-adrenergic vasoconstriction.

[The posterior auricular artery of the dog]

This investigation was made on the ramifications and distribution territories of the posterior auricular artery of fifty adult dogs utilizing the plastic injection method, comparing with those of the cat. In general, the posterior auricular artery of the dog arose independently from the posterior wall of the external carotid artery at a position where it passed across the superior margin of the digastricus muscle, distal to the origin of the facial artery. In six cases of all examples observed, the posterior auricular artery arose independently from the external carotid artery at a position where it passed across the inferior margin of the digastricus muscle, proximal to the origin of the lingual artery. As principal branches, the posterior auricular artery gave rise to the parotid glandular, the digastric muscular and the strong, cervical branches in this order. It finally terminated to the temporal muscular and the major auricular branches after giving off the occipital branch and the stylomastoid artery. The distribution territories of the posterior auricular artery of the dog, being similar to those of the cat, were not only the auricule but also the muscles of the mastication, the salivary glands, the middle ear and the retromandibular regions.

Calcitonin gene-related peptide in rat salivary glands: neuronal localization, depletion upon nerve stimulation, and effects on salivation in relation to substance P

Calcitonin gene-related peptide (CGRP)-immunoreactive nerve fibres occurred predominantly around blood vessels and large ducts and, to a minor extent, around acini and small ducts in the parotid, sublingual and submaxillary glands of the rat. Double immunostaining showed most of the CGRP-containing nerve fibres to contain substance P. However, the vast majority of substance P-immunoreactive periacinar nerve fibres in the parotid and submandibular glands lacked CGRP. After parasympathetic denervation of the parotid gland by section of the auriculotemporal nerve these periacinar substance P-immunoreactive nerve fibres disappeared almost completely, whereas the number of substance P/CGRP-immunoreactive nerve fibres seemed unchanged. After this operation the total amount of substance P in the parotid gland was reduced by about 90% as judged by radioimmunoassay; in denervation experiments the facial nerve was found to contribute to the residual substance P content. In contrast, the contribution of the auriculotemporal nerve to the CGRP content of the gland was small; the reduction in CGRP after section of the nerve was 20%. The facial nerve and the dorsal root nerves (C3 and C4) contributed to the CGRP content with about 50%. The source of the remaining 30% of the parotid gland CGRP is unknown. It is not the sympathetic nerve: sympathetic denervation resulted in a marked increase in CGRP, regardless of whether the auriculotemporal nerve was intact or not. Upon long-lasting electrical stimulation of the auriculotemporal nerve at a high frequency the parotid gland content of CGRP was gradually reduced, indicating depletion of this peptide in response to nerve stimulation. Intravenous injections of CGRP evoked no salivary flow; however, a release of amylase was revealed. Also, when CGRP was tested on isolated parotid gland lobules amylase was released into the medium. When, in vivo, CGRP was injected in combination with substance P, the substance P-evoked flow of parotid and submaxillary saliva was markedly enhanced. In addition, CGRP enhanced the in vivo secretory response to parasympathomimetics and to vasoactive intestinal peptide. The localization of CGRP-containing nerve fibres suggests that CGRP is involved in the regulation of secretion and blood flow of salivary glands. CGRP may interact positively with acetylcholine and certain nonclassical transmitters, and it may be involved (together with other neuropeptides) in the atropine-resistant parasympathetic secretion occurring in the glands under study.

VIP and its homologues increase vascular conductance in certain endocrine and exocrine glands

The effects of vasoactive intestinal peptide (VIP) and related structural homologues on tissue vascular conductances were investigated in anesthetized male rats. VIP, peptide histidine isoleucine (PHI), secretin, growth hormone-releasing factor (GHRF), gastric inhibitory peptide (GIP), or saline was infused intravenously over 4 min. Tissue blood flows were measured during this time by use of 141Ce-labeled microspheres. Regional blood flows were normalized for any change in mean arterial blood pressure during infusions, and results were expressed in terms of tissue vascular conductance (C). Circulating thyrotropin (TSH), triiodothyronine (T3), and thyroxine (T4) levels were determined before and at 20 min and 2 h after treatment. Marked increases in thyroid, pancreatic, and salivary gland vascular Cs occurred during peptide infusions with the order of potency (VIP greater than PHI greater than secretin greater than GHRF greater than GIP) correlating with the degree of structural homology to VIP. PHI and secretin produced maximal increases in vascular Cs, which were the same as those obtained with VIP. Circulating TSH, T3, and T4 levels were not different from values in saline-infused rats after peptide treatments that caused striking increases in thyroid vascular C. In the adrenal, kidney, and testis, VIP and its homologues had little to no effect on vascular Cs. We subsequently measured regional vascular Cs during VIP infusions in the presence or absence of secretin.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of thyrotropin on the vascular conductance of the thyroid gland

It is well established that TSH from the anterior pituitary is the principal stimulatory agent in the physiological regulation of the thyroid gland. Chronic elevations of plasma TSH induce hyperplasia and hypertrophy of thyroid follicular cells and enlargement of blood capillaries. At low plasma TSH levels the thyroid gland atrophies. We have examined the vascular conductance (C = blood flow/mean arterial pressure) of the thyroid gland and several other tissues over a wide range of endogenous plasma TSH concentrations and after treatment with bovine TSH (bTSH) in rats. Tissue blood flows were determined using 15 +/- 5-microns diameter 141Ce-labeled microspheres in a modification of the reference sample microsphere technique. The microspheres were injected directly into the left cardiac ventricle via a 23-gauge needle passed through the chest wall, while the reference blood sample was collected and systemic arterial blood pressure was monitored through femoral arterial catheters. After the animals were killed, tissues were cleaned and weighed, and the tissue radioactivity was determined. Blood samples for determination of plasma hormone levels were obtained from the jugular vein before the injection of microspheres. In the first series of experiments, the vascular C per mass of thyroid gland was significantly decreased 4 and 8 days after hypophysectomy. Treatment of hypophysectomized rats with bTSH (185 mU/100 g.day as a continuous iv infusion for 2 or 6 days) restored thyroid vascular C per mass of tissue to control levels. In the second series of experiments, we manipulated circulating plasma TSH levels in intact rats by 6 days of treatment with propylthiouracil (2.0 mg/day, ip), thyroid hormones (1.5 micrograms T4, 0.4 micrograms T3 or 3.0 micrograms T4, plus 0.8 micrograms T3/100 g.day, sc by continuous infusion), TRH (240 micrograms/day, iv, by continuous infusion), bTSH (800 mU/day, iv, by continuous infusion), or combinations of these treatments. The vascular C per mass of thyroid gland was significantly decreased at very low chronic plasma TSH levels and increased at very high chronic plasma TSH levels. Thyroid vascular C per mass was unchanged, however, over a broad intermediate range of plasma TSH concentrations encompassing normal values, despite alterations in the size and function of the thyroid gland. At these intermediate levels of TSH stimulation, the thyroid gland may respond by adding or subtracting functional units without changing the blood flow per unit. The amount of blood flow per functional unit may be altered only at very high or very low levels of TSH stimulation.

[Structuro-functional units of the salivary and lacrimal glands]

By means of the multilayer graphic and plastic reconstruction methods using series of semithin sections, spatial tridimensional organization of the epithelial complexes and blood microcirculatory bed in the rat palatal salivary glands and the lacrimal gland of the human newborn have been studied. Since their ducts serve not only for discharging their secrete into the external medium, but also for accumulation (as collectors), the sublobular unit--adenomere should be referred to as a part of elementary level of organization of the epithelial complexes. The adenomere has in its composition a collecting centrally situating duct. However, while studying structure of the blood microcirculatory bed, it is found out that there is not any strict territorial correspondence between its functional units and structural units of the glandular epithelium. Nevertheless, giving a great importance to a tight syntopic connection of the collecting ducts of the adenomeres with the postcapillary venules (that belong to filtrating microvessels), these are sublobular units--adenomeres that are distinguished as structural-functional units in the glands.

Relationship between nailfold capillary microscopy and salivary capillary basement membrane width in Raynaud's disease and progressive systemic sclerosis

To assess the relationship between a nailfold scleroderma pattern and histopathological data, we compared the results of nailfold capillaroscopy with capillary basement membrane width of labial salivary glands in 25 patients with either a Raynaud's disease (RD: 12 patients) or a progressive systemic sclerosis (PSS: 13 patients). The sensitivity of a capillaroscopic scleroderma pattern for capillary basement membrane thickness is of 75%. These results confirm the usefulness of in vivo capillary examination for the early diagnosis of PSS.

[Mechanism of the development of functional hyperemia in the palatal salivary glands of the rat]

At various regimens of the secretory activity in the palatile salivary glands, changes occurring in the transversal profiles of the postcapillary venules, but not of the blood capillaries, are most noticeable. Under food stimulation of secretion, the former dilate essentially, that can demonstrate certain functional hyperemia developing in the palatine salivary glands. Some previous experiments concerning interpretation of principles on the microcirculatory bed spatial organization give a good reason to suggest that dilatation of the postcapillary venules is connected with an increased blood perfusion in the canals of the preferrable blood stream. The postcapillary dilatation is possible because blood from the precapillaries gets into the capacitance blood microvessels and its volume at that moment is greater than the capacity of the venous microvessels. A suggestion is made that filtrative function of the palatile salivary glands depends on development of the functional hyperemia. It is possible, that this mechanism is universal, since owing to it, reflectory reactions of the salivary glands directed to the immediate secure of the oral cavity with a necessary amount of liquor become possible.

Endothelial specialization of salivary gland vessels for accelerated lymphocyte transfer in Sjögren's syndrome

We describe vessels within the lymphocytic infiltrate of the salivary glands in Sjögren's syndrome that are identical to those specialized for lymphocyte transport in lymph nodes. These vessels may represent a mechanism for increased lymphocyte traffic into the gland and thereby contribute significantly to the inflammatory process.

The microvasculature of rat salivary glands. A scanning electron microscopic study

The blood vessels together with the parenchymal components of rat salivary glands were studied by scanning electron microscopy (SEM) after removal of stromal connective tissue by acid hydrolysis plus enzymatic digestion. The three-dimensional vascular architecture was also studied by SEM of vascular corrosion cats. Each cluster of 4-5 polymorphous acini is connected with the convoluted duct via an intercalated duct. The convoluted duct usually has a sigmoid course and drains to the intralobular striated duct (about 20 microns in diameter); this has a rather straight course before connecting with the interlobular excretory duct. Myoepithelial cells with radiating processes were observed on the stromal surface of the secretory acini. Pericytes with longitudinal and circular processes were also observed surrounding the stromal surface of capillaries. The acini and convoluted ducts are surrounded by plexuses of capillaries derived from terminal arterioles which run along the intralobular duct system. The sinusoidal capillary plexus enveloping the striated duct receives blood from capillaries surrounding the acini and convoluted ducts through portal venules. The interlobular excretory ducts are richly supplied by a subepithelial network of capillaries which receive blood directly from the interlobular artery and drain into the interlobular vein. Thus, the excretory duct circulation is separated from the intralobular circulation. No arterio-venous anastomoses were observed in the gland. However, veno-venous and arterio-arterial anastomoses were often seen along the excretory duct; such anastomoses may participate in controlling the direction of blood flow through the vascular plexus around the excretory duct. The well-developed subepithelial plexus of capillaries observed around this duct is appropriate for its known absorptive/secretory functions. The capillary network around the acini is densest in the parotid gland and sparsest in the sublingual gland. The subepithelial capillary network of the excretory ducts of the submaxillary gland is denser than those of the other two glands which had similar densities.

Microvasculature as studied by the microvascular corrosion casting/scanning electron microscope method. I. Endocrine and digestive system

This paper reviews firstly the microvascular corrosion casting/scanning electron microscope method and secondly the microvascular organization of endocrine and digestive system as revealed by this technique. Detailed descriptions of the microvascular arrangement of the hypophysis, pineal body, thyroid gland, pancreas, adrenal gland, salivary gland, liver, stomach and small intestine are given. Various hypotheses are also proposed regarding the physiological significance of the microcirculatory patterns observed.