Effects of duct ligation on choline acetyltransferase activity in salivary glands of rats

Duct ligation was found to cause a decrease in the weights of submaxillary and parotid glands examined 3 weeks postoperatively. Choline acetyltransferase activity in ligated glands was compared with that in unligated contralateral glands. The enzyme activity was also measured in the glands from both sides of unoperated control animals. Interference in the assay of choline acetyltransferase by other acetylated compounds was avoided by introducing suitable control incubations. Ligated submaxillary glands showed a small decrease in the activity of choline acetyltransferase both when compared with contralateral glands and with glands of control rats. In parotid glands the enzyme activity was found to be lower only when ligated and contralateral glands were compared. Structural changes in the nerves and reduced traffic of impulses in them may have to be considered as explanations for the reduction in enzyme activity in duct–ligated glands.     

Simple method to isolate the intact duct system of the rat submandibular gland

The excurrent duct system of the rat submandibular gland consists of a number of distinct segments. Using the direction of salivary flow as a reference point, these segments are, in order, intercalated duct, granular convoluted tubule, striated duct, excretory duct, main excretory duct (MED), and salivary bladder (which is an expanded portion of the MED). Because these ducts (with the exception of the MED and the salivary bladder) are encased in secretory endpieces, they are difficult to locate and to observe by scanning electron microscopy. A simple method has been devised to rid the gland of these obscuring endpieces so that the detailed architecture of the duct system can be examined. Rat submandibular glands were fixed initially by vascular perfusion with half‐strength Karnovsky's fixative. The connective tissue capsule was removed from extirpated glands and the glands remained in fixative for varying lengths of time. For our purposes, a 30‐minute immersion in the aldehyde mixture was optimum. After the sublingual gland was removed, the submandibular gland was softy struck with forceps having rounded tips, then shaken in fixative or buffer. The tissue that remained was postfixed in osmium tetroxide. This method results in the complete divestment of nonductular parenchyma from the rat submandibular gland, leaving the duct system clean and ready for microscopic examination. Anat Rec 254:74–75, 1999. © 1999 Wiley‐Liss, Inc.     

Cell death and cell proliferation during atrophy of the rat parotid gland induced by duct obstruction

Rat parotid gland atrophy after unilateral duct ligation was studied by light and electron microscopy. Death of secretory acinar cells, which took the form of apoptosis, resulted in their complete disappearance within 5 days. The remnants of the dying cells were mostly phagocytosed and degraded by macrophages within the glandular epithelium; a few were taken up by adjoining epithelial cells. The acinar cell deletion was accompanied by increased mitosis of striated and intercalated duct epithelial cells. However, over many weeks, there was enhanced apoptosis of duct cells, which eventually led to marked shortening of intercalated ducts. Apoptosis of capillary endothelial cells was observed and may account for the reduction in the capillary bed known to accompany gland atrophy. The end-stage lesion comprised small numbers of ducts in a condensed stroma. Compensatory hyperplasia, involving proliferation of duct and acinar cells, was demonstrated in the contralateral glands.     

Reaction of the rat submandibular salivary gland to injury to the contralateral gland

After burns of resection of the submandibular salivary gland the intact contralateral gland in rats responds by increased proliferative activity. The number of mitoses reached a maximum 72 h after injury in the case of burns and 48 h after resection. Burns of the salivary gland cause lasting but weak compensatory hypertrophy of the contralateral gland. Hypertrophy of the gland is accompanied by an increase in size of the cells and nuclei, the area of which rises by 10 and 17% respectively. Resection of the salivary gland causes an increase in weight of the intact gland only in the early period of observation; by the 30th and 45th days after the operation the weight of the experimental glands was not significantly different from the control. Differences in compensatory growth of the intact glands observed after two types of injury of the contralateral gland evidently depend on the quantity of tissue breakdown products and the duration of their presence in the body.Department of Biology and General Genetics, Moscow Medical Stomatological Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 9, pp. 1108–1110, September, 1976.     

下颌下腺主导管结扎可激活损伤组织中的干/祖细胞

背景：成体干细胞的伦理学问题较少,而且某些操作技术比较成熟,利用成体干细胞进行组织工程化涎腺的构建具有十分诱人的吸引力和极其重要的应用前景。 目的：建立下颌下腺主导管结扎的涎腺组织损伤大鼠模型,探讨涎腺组织损伤模型中成体干/祖细胞存在的可能性及可能位置。 方法：SD大鼠统一行右侧下颌下腺主导管结扎,1周后处死大鼠取出两侧腺体,通过苏木精-伊红染色、PAS糖原染色及细胞角蛋白19、Bcl-2、Ki-67等指标的免疫组织化学测定,对正常涎腺组织与建立的损伤模型组织进行比较。 结果与结论：同一只大鼠,结扎侧与对照侧体积、质量有明显的差异。对照侧下颌下腺组织呈卵圆形,色泽红润,表面光滑,有完整包膜,质地柔软;结扎后腺体萎缩,组织形态欠规整,色泽暗红,包膜充血,质地变韧,周围组织血管代偿性扩张。主导管结扎的组织损伤模型可导致PAS阳性腺细胞的消失和细胞角蛋白19阳性的小导管上皮细胞增殖,并有在未结扎的腺体中很少见到的小丛层粘连蛋白阳性细胞出现在导管周围,而抑制细胞凋亡的Bcl-2和提示增殖活跃度的Ki-67的表达均有所增强。可见下颌下腺组织中可能存在着定位于涎腺周围导管区的下颌下腺干/祖细胞;下颌下腺主导管结扎导致的组织损伤模型是一种能有效激活下颌下腺组织中干/祖细胞的方法。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

Altered plasticity of the parasympathetic innervation in the recovering rat submandibular gland following extensive atrophy

Adult rat submandibular glands have a rich autonomic innervation, with parasympathetic and sympathetic nerves working in synergy rather than antagonistically. Ligation of the secretory duct rapidly causes atrophy and the loss of most acini, which are the main target cell for parasympathetic nerves. Following deligation, there is a recovery of gland structure and function, as assessed by autonomimetic stimulation. This study examines whether the parasympathetic nerves reattach to new target cells to form functional neuro-effector junctions. Under recovery anaesthesia, the submandibular duct of adult male rats was ligated via an intra-oral approach to avoid damaging the chorda-lingual nerve. Four weeks later, rats were either killed or anaesthetized and the ligation clip removed. Following a further 8 weeks, both submandibular ducts were cannulated under terminal anaesthesia. Salivary flows were then stimulated electrically (chorda-lingual nerve at 2, 5 and 10 Hz) and subsequently by methacholine (whole-body infusion at two doses). Glands were excised, weighed and divided for further in vitro studies or fixed for histological examination. Ligation of ducts caused 75% loss of gland weight, with the loss of most acinar cells. Of the remaining acini, only 50% were innervated despite unchanged choline acetyltransferase activity, suggesting few parasympathetic nerves had died. Following deligation, submandibular glands recovered half their weight and had normal morphology. Salivary flows from both glands (per unit of gland tissue) were similar when evoked by methacholine but greater from the deligated glands when evoked by nerve stimulation. This suggests that parasympathetic nerves had reattached to new target cells in the recovered glands at a greater ratio than normal, confirming reinnervation of the regenerating gland.     

Fine-needle aspiration cytology of an oncocytic carcinoma of the submandibular gland

An oncocytic carcinoma of the submandibular gland diagnosed by fine-needle aspiration is reported. Cytologically, the tumor cells occurred singly, in three-dimensional clusters and in multilayered sheets. The cells had round-to-oval, centrally or eccentrically located nuclei with fine chromatin and prominent nucleoli. Many cells contained abundant granular cytoplasm and well-defined cell borders; however, several stripped nuclei with prominent nucleoli were also noted in the background. Follow-up histologic examination showed tumor cells arising from right submandibular gland and metastasizing to six of 14 cervical lymph nodes. Ultrastructural study demonstrated tumor cells packed with mitochondria in the cytoplasm. The patient was alive with no evidence of disease 6 months after the surgery. Diagn. Cytopathol. 1998;19:186–189. © 1998 Wiley-Liss, Inc.     

Origin of acinar cell regeneration after atrophy of the rat parotid induced by duct obstruction

Acinar cell regeneration in the rat parotid gland after atrophy induced by a one week period of duct obstruction was examined using histology, immunohistochemistry and transmission electron microscopy (TEM). For immunohistochemistry, antibodies to 5-bromo-2'-deoxyuridine (BrdU), injected one hour before tissue collection, and cytokeratin were employed. When clips were removed from the duct, only ductal epithelial cells remained; all acinar cells had been deleted. Some duct cells were BrdU positive. After three days, newly-formed acini comprising immature acinar cells had appeared; many of the cells were BrdU positive and mitotic figures were readily identified. Thereafter progressive acinar cell maturation and proliferation occurred, parotid gland weight returning to control levels by 7 days. Peak BrdU labelling indices for duct and acinar cells were on days 0 and 4, respectively. By TEM, cytoplasmic organelles in epithelial cells of transitional duct-acinar structures seen at 2 days were poorly developed. Immature acinar cells seen on day 3 contained zymogen granules and had increased endoplasmic reticulum and mitochondria. By day 5, maturing acinar cells had abundant endoplasmic reticulum and zymogen granules, resembling acinar cells in control glands. These observations indicated origin of acinar cell precursors from duct cells during regeneration of the acinar cell-free atrophic gland. Subsequent expansion of the acinar cell population was dependent on maturation and proliferation of these newly-formed cells.     

Participation of the Fas and Fas ligand systems in apoptosis during atrophy of the rat submandibular glands

Most acinar cells and some duct cells undergo apoptosis during atrophy of the submandibular gland. The present study was designed to elucidate whether Fas and its receptor ligand (FasL) are involved during apoptotic atrophy of the gland. The excretory duct of the right submandibular gland of rats was doubly ligated with metal clips from 1 to 14 days for induction of gland atrophy. Control rats were untreated. Fas and FasL expression in the atrophied submandibular gland was detected using immunohistochemistry (IHC) and Western immunoblot. Expression of activated caspase 8 and activated caspase 3 was also detected with IHC. Fas-positive acinar and duct cells and FasL-positive duct cells increased in the atrophic glands at 3 and 5 days after duct ligation when apoptotic cells were commonly observed. Thereafter, Fas- and FasL-positive cells declined in number. Patterns of expression of Fas and FasL using Western immunoblots concurred with the IHC results. Activated caspase 8-positive cells were present at every time interval but peaked at 3 and 5 days following duct ligation. The cells showing immunoreaction for activated caspase 3 first appeared on day 3, with the peak in apoptosis, after which they decreased. The results indicate that the Fas/FasL systems likely play an important role in apoptotic pathways during atrophy of the submandibular gland.     

Sympathetic denervation affects the choline acetyltransferase activity in decentralized parasympathetic neurones of the submaxillary gland of the rat

Parasympathetic decentralization of the rat submaxillary gland caused the activity of the acetylcholine forming enzyme, choline acetyltransferase, to decrease. No such decrease in the enzyme activity was observed when parasympathetic decentralization was combined with sympathetic denervation and further, if the two types of operation were carried out in sequence the enzyme activity could be shown to increase from a reduced level. Thus in contrast to previous concept the present study shows that the activity of choline acetyltransferase in the postganglionic nerves can be influenced by sympathetic denervation in spite of the fact that these nerves are not in contact with the central nervous system. The choline acetyltransferase activity was not affected by preganglionic sympathetic denervation.     

Salivary duct carcinoma in situ of the parotid gland

Aims: To describe three cases of purely in situ salivary duct carcinoma, so as better to define the entity. Methods and results: Three primary tumours of the parotid gland are presented, in each case composed of cysts and ducts and lined by high nuclear grade epithelial cells. All parts of each tumour were surrounded by a myoepithelial cell rim and there was no evidence of invasion. The tumour cells expressed immunohistochemical markers seen in invasive salivary duct carcinoma of usual (high‐grade) type. In two cases the androgen receptor (AR) reaction was strong, but there was no immunohistochemical expression of HER2 protein or gene amplification by in situ hybridization. In the remaining case, fewer nuclei stained for AR, but both HER2 protein and gene amplification were demonstrated. Conclusions: Salivary duct carcinoma in situ is morphologically similar to breast ductal carcinoma in situ and, although our cases are few, salivary duct carcinoma in situ can possibly be subdivided into luminal and non‐luminal cell types, as can analogous mammary neoplasms. The present study cannot determine whether low‐grade cribriform cystadenocarcinoma, architecturally similar but immunohistochemically different, is part of the spectrum of salivary duct carcinoma in situ, or whether it represents a separate entity.     

大鼠坐骨神经结扎后背根神经节神经生长因子的表达变化

目的:观察坐骨神经结扎后神经生长因子(NGF)在背根神经节的表达变化.方法:健康SD大鼠随机分为正常对照组、假手术对照组和坐骨神经结扎组,实验组结扎后分别存活1、 3、 5、 7、 14、 21、 28d,取腰4～6背根神经节(DRG),行NGF免疫组织化学显色结合图像分析技术分析其表达变化.结果:结扎后1d DRG NGF表达无明显变化;3d开始下降,7d达最低值,持续到21d;28d恢复正常.结论:神经结扎后DRG神经元NGF表达变化可能参与了神经损伤后的可塑性.     

Recovery of rat submandibular salivary gland function following removal of obstruction: a sialometrical and sialochemical study

Functional recovery of the rat submandibular gland following ligation of the main excretory duct was examined. Rat submandibular glands were ligated for 1, 4 and 8 weeks using a micro-clip with a plastic tube. Micro-clips were removed and glands were allowed to recover for periods of 8, 16 and 24 weeks. Submandibular glands were stimulated with autonomimetic drugs (methacholine and isoprenaline) and salivas were collected from atrophic or de-ligated and contralateral control glands. Glands recovered almost full size (92% of control gland) following 24 weeks of de-ligation. Saliva volume secreted by ligated/de-ligated (RSM) and control (LSM) glands were similar with different doses of agonists. Protein output expressed per gram of tissue wet weight was similar from both ligated/de-ligated and control glands with all doses of agonist. Sodium and chloride levels were higher from de-ligated glands than contralateral control glands. Protein electrophoresis showed similar profiles of salivary proteins in all samples with some minor differences. Acinar cells in de-ligated glands showed a normal morphology, as indicated by light microscopy, whilst granular ductal cells were fewer and contained fewer secretory granules. Sodium potassium ATPase staining of striated ducts in de-ligated glands was similar to that of control glands. It can be concluded that rat submandibular glands can regenerate following severe atrophy and secrete normal amounts of saliva containing broadly a full profile of secretory proteins. In contrast to acinar cells, ductal cells appear not to recover full function.     

陈旧性坐骨神经缺损对大鼠腓肠肌组织蛋白含量及泛素表达的影响

目的：了解陈旧性坐骨神经缺损后肌肉萎缩过程中蛋白质降解的机制。方法：用SD大鼠建立坐骨神经缺损模型,切断大鼠右侧坐骨神经,形成10 mm缺损。测定术后1、2、3、4、6、9及12个月腓肠肌肌总蛋白的含量;免疫组化法观察组织中泛素的表达变化;Western印迹法测定组织中泛素蛋白的表达水平。结果：坐骨神经缺损后腓肠肌肌总蛋白含量随缺损时间延长呈进行性下降;正常腓肠肌组织中泛素呈低表达,随缺损时间延长泛素表达水平增强,持续到9个月,随后呈下调趋势。结论：陈旧性坐骨神经缺损后腓肠肌蛋白的降解、肌总蛋白量下降及肌萎缩可能和泛素-蛋白酶体途径有关。     

A case of oncocytic lipoadenoma of the submandibular gland and its diagnostic cytology challenges

Lipomatous tumors of the salivary gland in general are rare and oncocytic lipoadenomas are even much rarer. Most of the reported cases of oncocytic lipoadenoma were located in the parotid gland and to the best of our knowledge, only four cases reported to arise from the submandibular gland. The preoperative interpretation of the aspirates taken from these lesions can be difficult and challenging. We report a case of a 41 year old gentleman who presented with submandibular gland swelling. CT scan of the neck revealed an oval‐shape enhancing mass in the inferior aspect of the right submandibular gland measuring 19 × 12 mm. Fine needle aspiration biopsy (FNAB) showed hypocellular smears with few clusters of epithelial cells having oncocytic appearance. The cytologic findings were interpreted as “oncocytic lesion.” Submandibular gland excision was done. Histologically, a final diagnosis of oncocytic lipoadenoma was rendered. We present this rare entity to add to the few cases reported to date and to upsurge awareness during cytologic examination of oncocytic salivary gland lesions.     

Sebaceous carcinoma of the submandibular gland with high-grade malignancy: Report of a case

A case of sebaceous carcinoma arising in the left submandibular gland of a 66-year-old man is reported. The clinical and pathological examinations revealed a carcinoma, which was of salivary gland In origin, with regional lymph nodal metastases. Pathological findings showed features of highgrade sebaceous carcinoma with spindle myoepitheliomatous differentiation. Neither squamous cell nor duct epithelial-like cell differentiation was noted. lmmunohistochsmically, tumor cells were positive for cytokeratin, S-100 protein and vimentin. Lipid was demonstrated in the cytoplasm of the tumor cells. Ultrastructurally, tumor cells contained numerous intracyto-plasmic lipid droplets. Myoepitheliomatous differentiation is rare in sebaceous carcinoma of the salivary gland. Presented is the second reported case of sebaceous carcinoma arising in the submandibular gland.     

Cost efficiency analysis for fine-needle aspiration in the workup of parotid and submandibular gland nodules

The utility and cost effectiveness of salivary gland fine-needle aspiration (FNA) is controversial. Some authorities argue FNA has no added value over clinical-radiographic study because most salivary gland nodules occur in the parotid and the tumor's relationship to the facial nerve determines the operative procedure rather than the histology. Other experts contend FNA is of value by reducing the overall number of operative procedures performed.We studied 306 salivary gland nodules (214 parotid and 92 submandibular gland) undergoing FNA. One hundred and seventy one were subsequently surgically resected and the remaining 135 followed clinically. A 16% error rate was associated with the nonoperative group, necessitating later surgical resection. The cost of the FNAs and surgical resections (when performed) was calculated based on Medicare reimbursement rates. Costs were based on all cases undergoing initial FNA. The expense of initial resection was based on the observed percentage of patients undergoing resection in our series. The costs of resections related to erroneous FNA diagnoses were based on the error rate associated with FNA diagnoses clinically followed (i.e., chronic sialadenitis). Costs of FNAs, initial resections, and subsequent resections related to FNA errors were summed and compared with the cost which would have occurred if all nodules had been primarily resected.FNA reduced the number of operative procedures by approximately 65% for submandibular nodules and 35% for parotid nodules. Diagnoses which resulted in nonsurgical management included chronic radiation-induced sialadenitis, intraparotid lymph node, recurrent lymphoma, and accessory nodules or lobes of the parotid gland. Pure surgical management was associated with a cost of $275,750.00 per 100 patients. FNA management was associated with an expenditure of $206,632.00 per 100 patients, representing a savings of $69,118.00 (33% savings over surgical management alone).Based on these data, FNA appears to be cost effective in addition to supplying preoperative diagnoses helpful in counseling, operative planning, and allaying patient anxiety.