Ketone bodies effectively compete with glucose for neuronal acetyl‐CoA generation in rat hippocampal slices

Ketone bodies can be used for cerebral energy generation in situ, when their availability is increased as during fasting or ingestion of a ketogenic diet. However, it is not known how effectively ketone bodies compete with glucose, lactate, and pyruvate for energy generation in the brain parenchyma. Hence, the contributions of exogenous 5.0 mM [1‐¹³C]glucose and 1.0 mM [2‐¹³C]lactate + 0.1 mM pyruvate (combined [2‐¹³C]lactate + [2‐¹³C]pyruvate) to acetyl‐CoA production were measured both without and with 5.0 mM [U‐¹³C]3‐hydroxybutyrate in superfused rat hippocampal slices by ¹³C NMR non‐steady‐state isotopomer analysis of tissue glutamate and GABA. Without [U‐¹³C]3‐hydroxybutyrate, glucose, combined lactate + pyruvate, and unlabeled endogenous sources contributed (mean ± SEM) 70 ± 7%, 10 ± 2%, and 20 ± 8% of acetyl‐CoA, respectively. With [U‐¹³C]3‐hydroxybutyrate, glucose contributions significantly fell from 70 ± 7% to 21 ± 3% (p < 0.0001), combined lactate + pyruvate and endogenous contributions were unchanged, and [U‐¹³C]3‐hydroxybutyrate became the major acetyl‐CoA contributor (68 ± 3%) – about three‐times higher than glucose. A direct analysis of the GABA carbon 2 multiplet revealed that [U‐¹³C]3‐hydroxybutyrate contributed approximately the same acetyl‐CoA fraction as glucose, indicating that it was less avidly oxidized by GABAergic than glutamatergic neurons. The appearance of superfusate lactate derived from glycolysis of [1‐¹³C]glucose did not decrease significantly in the presence of 3‐hydroxybutyrate, hence total glycolytic flux (Krebs cycle inflow + exogenous lactate formation) was attenuated by 3‐hydroxybutyrate. This indicates that, under these conditions, 3‐hydroxybutyrate inhibited glycolytic flux upstream of pyruvate kinase. Copyright © 2015 John Wiley & Sons, Ltd.     

Hyperpolarized 13C‐lactate to 13C‐bicarbonate ratio as a biomarker for monitoring the acute response of anti‐vascular endothelial growth factor (anti‐VEGF) treatment

Hyperpolarized [1‐¹³C]pyruvate MRS provides a unique imaging opportunity to study the reaction kinetics and enzyme activities of in vivo metabolism because of its favorable imaging characteristics and critical position in the cellular metabolic pathway, where it can either be reduced to lactate (reflecting glycolysis) or converted to acetyl‐coenzyme A and bicarbonate (reflecting oxidative phosphorylation). Cancer tissue metabolism is altered in such a way as to result in a relative preponderance of glycolysis relative to oxidative phosphorylation (i.e. Warburg effect). Although there is a strong theoretical basis for presuming that readjustment of the metabolic balance towards normal could alter tumor growth, a robust noninvasive in vivo tool with which to measure the balance between these two metabolic processes has yet to be developed. Until recently, hyperpolarized ¹³C‐pyruvate imaging studies had focused solely on [1‐¹³C]lactate production because of its strong signal. However, without a concomitant measure of pyruvate entry into the mitochondria, the lactate signal provides no information on the balance between the glycolytic and oxidative metabolic pathways. Consistent measurement of ¹³C‐bicarbonate in cancer tissue, which does provide such information, has proven difficult, however. In this study, we report the reliable measurement of ¹³C‐bicarbonate production in both the healthy brain and a highly glycolytic experimental glioblastoma model using an optimized ¹³C MRS imaging protocol. With the capacity to obtain signal in all tumors, we also confirm for the first time that the ratio of ¹³C‐lactate to ¹³C‐bicarbonate provides a more robust metric relative to ¹³C‐lactate for the assessment of the metabolic effects of anti‐angiogenic therapy. Our data suggest a potential application of this ratio as an early biomarker to assess therapeutic effectiveness. Furthermore, although further study is needed, the results suggest that anti‐angiogenic treatment results in a rapid normalization in the relative tissue utilization of glycolytic and oxidative phosphorylation by tumor tissue. Copyright © 2016 John Wiley & Sons, Ltd.     

Pure intraductal carcinoma of the parotid gland: Cytologic findings on FNA sample. Report of one case

One case of intraductal carcinoma of the parotid gland in a 67‐year‐old male patient is here introduced. The patient, who had a one‐year history of a parotid mass, had undergone ultrasound and MRI examination that disclosed a 13x4x3 mm well delimited nodular mass of the accessory lobe of his left parotid gland. Ultrasound‐guided Fine Needle Aspiration (FNA) had been performed by the clinician. The obtained smears showed widespread cellular necrosis in which cellular clusters with moderate and focally severe atypias displayed papillary and cribriform architecture and were admixed with sheets of epithelial cells with less striking nuclear atypias, squamous, or apocrine metaplasia. Histopathological examination disclosed a pure intraductal carcinoma of the parotid gland with classical morphology, which was radically excised. The differential cytological diagnosis of pure intraductal carcinoma of salivary glands may be difficult and comprises mucoepidermoid carcinoma as well as “in situ” carcinomas developping in the context of sclerosing polycystic adenosis, mammary analogue secretory carcinoma (MASC) of the salivary glands and cystic variants of salivary adenocarcinoma NOS (formerly called cystadenocarcinomas).     

Human salivary gland morphogenesis: myoepithelial cell maturation assessed by immunohistochemical markers

Ianez R F, Buim M E, Coutinho‐Camillo C M, Schultz R, Soares F A & Lourenço S V
(2010) Histopathology 57 , 410–417
Human salivary gland morphogenesis: myoepithelial cell maturation assessed by immunohistochemical markers Aims: Myoepithelial cells are important components of salivary gland structure, aiding the expulsion of saliva from acinar lobules. The aim was to evaluate the expression of smooth muscle actin (SMA), calponin, caldesmon, CD10, CD29, S100 protein, glial fibrillary acidic protein (GFAP) and p63 in myoepithelial cells during salivary gland morphogenesis to understand the maturation process of these cells and their possible use in the diagnosis of salivary gland lesions. Methods and results: Major and minor human salivary glands at various stages of development, derived from fetuses at 8–26 weeks of gestation, were studied immunohistochemically. Fully developed salivary glands were used as controls. The protein p63 was present in all stages of salivary gland morphogenesis from initial bud to terminal bud stage. CD29, S100 and calponin were detected increasingly as salivary gland structure matured and in fully developed salivary gland. Proteins GFAP, CD10 and caldesmon were not observed in myoepithelial cells of salivary glands. Conclusions: The proteins SMA, calponin, CD29, S100 and p63, which are present from the earliest stages of salivary gland maturation, are valuable myoepithelial markers but, although very specific, are not exclusive markers for this cell type.     

Characterization of the myoepithelial cells in the major salivary glands of the fruit bat Artibeus jamaicensis

Bats constitute one of the most numerous mammalian species. Bats have a wide range of dietary habits and include carnivorous, haematophagous, insectivorous, frugivorous and nectivorous species. The salivary glands of these species have been of particular research interest due to their structural variability among chiropterans with different types of diets. Myoepithelial cells (MECs), which support and facilitate the expulsion of saliva from the secretory portions of salivary glands, are very important for their function; however, this cell type has not been extensively studied in the salivary glands of bats. In this study, we characterized the MECs in the major salivary glands of the fruit bat Artibeus jamaicensis. Herein, we describe the morphology of the parotid, submandibular and sublingual glands of A. jamaicensis at the light‐ and electro‐microscopic level and the distribution of MECs in these glands, as defined by their expression of smooth‐muscle markers such as α‐smooth muscle actin (SMAα) and desmin, and of epithelial cell markers, such as KRT14. We found that the anatomical locations of the major salivary glands in this bat species are similar to those of humans, except that the bat sublingual gland appears to be unique, extending to join the contralateral homologous gland. Morphologically, the parotid gland has the characteristics of a mixed‐secretory gland, whereas the submandibular and sublingual glands were identified as mucous‐secretory glands. MECs positive for SMAα, KRT14 and desmin were found in all of the structural components of the three glands, except in their excretory ducts. Desmin is expressed at a lower level in the parotid gland than in the other glands. Our results suggest that the major salivary glands of A. jamaicensis, although anatomically and structurally similar to those of humans, play different physiological roles that can be attributed to the dietary habits of this species.     

PLAG1 immunohistochemistry is a sensitive marker for pleomorphic adenoma: a comparative study with PLAG1 genetic abnormalities

Aims

Pleomorphic adenoma gene 1 (PLAG1) gene rearrangement is the most common genetic abnormality in pleomorphic adenoma (PA), resulting in overexpression of PLAG1 protein. PA and carcinoma ex pleomorphic adenoma (CA ex‐PA) can mimic various benign and malignant salivary gland tumours. The aims of this study are to evaluate the sensitivity and specificity of PLAG1 immunohistochemistry (IHC) in the differential diagnosis of PA and CA ex‐PA and to compare the PLAG1 immunohistochemical results to PLAG1 gene abnormalities as detected by fluorescence in‐situ hybridisation (FISH).

Methods and results

PLAG1 immunostaining was performed on 83 salivary gland tumours, including 23 PA, 15 CA ex‐PA and 45 other salivary gland tumours. In addition, PLAG1 FISH was performed in 44 cases for the presence of gene rearrangements/amplifications. The results showed high sensitivity of PLAG1 IHC in 96% of PA; however, discordant results between PLAG1 FISH abnormalities and IHC were noted in 15 of 44 cases (34%). Seven PA, four de‐novo myoepithelial carcinomas and one basal cell adenocarcinoma had negative FISH results, but were positive for IHC; while three salivary duct carcinomas (SDC) ex‐PA were positive for FISH but negative for IHC. PLAG1 IHC can differentiate CA ex‐PA from de‐novo SDC (P = 0.02), but not from de‐novo myoepithelial carcinoma. PLAG1 IHC is a sensitive marker for PA. This could be due to PLAG1 gene abnormalities beyond FISH resolution.

Conclusions

A negative PLAG1 IHC might be helpful in excluding a PA diagnosis. Interestingly, in the context of CA ex‐PA, FISH is more sensitive than IHC in detecting PLAG1 abnormalities.     

Expression of cyclooxygenase-1 (COX-1) in labial salivary glands of Sjögren's syndrome

COX plays an important role in inflammatory diseases such as rheumatoid arthritis. To determine the role of COX in Sjögren's syndrome (SS), we examined COX expression in the salivary glands of SS patients. We examined 15 patients with SS and two normal subjects. Labial salivary gland tissue samples were analysed immunohistochemically using anti‐COX‐1 and COX‐2 antibodies. All biopsy samples from 15 patients with SS were stained for COX‐1. In contrast, COX‐1 immunostaining was not detected in normal salivary gland tissues. Co‐expression of COX‐1 and CD68 was confirmed by mirror section technique and double antibody immunostaining. This finding indicated that COX‐1‐expressing cells in SS salivary glands were infiltrating macrophages. In contrast to COX‐1 staining, only a little COX‐2 immunostaining was observed in salivary gland tissues from SS patients. These data suggest that COX‐1 expression on infiltrating macrophages may contribute to the inflammatory process of salivary glands in SS.     

Renal cell carcinoma in acquired cystic kidney disease

Yakirevich E, Sabo E, Klorin G, Alos L, Cardesa A, Ellis G L, Shumway B S & Gnepp D R
(2010) Histopathology 57, 395–409
Primary mucin‐producing tumours of the salivary glands: a clinicopathological and morphometric study Aims: To determine clinicopathological and morphometric features that discriminate between mucin‐producing primary salivary gland carcinomas. Materials and results: Fifteen mucin‐producing tumours were stratified into five colloid carcinomas (CCs), four mucinous cystadenocarcinomas (MCAs), three mucin‐rich salivary duct carcinomas (SDCs) and three mucin‐rich mucoepidermoid carcinomas (MECs). The mean patient age was 70, 58, 43 and 63 years for CC, MCA, SDC and MEC, respectively. Eleven of 15 patients were female. The majority of CC cases originated from major salivary glands; MCA showed a predilection for the minor salivary glands. No disease‐related mortality was observed in the CC group; one patient died in the MCA group, and one in the SDC group. Receiver–operating characteristic curve analysis revealed an optimal cut‐off point of 17% of the tumour cells in contact with stroma that best distinguished between the CC and MCA. Histomorphometric measurements revealed that CC was best differentiated from MCA by smaller nuclear size and more regular chromatin. Conclusions: Strict morphological criteria of CC coupled with assessment of the tumour cell/stroma relationship and the nuclear features facilitate discrimination between mucinous tumours of salivary gland.     

Histological and Ultrastructural Characterization of Developing Miniature Pig Salivary Glands

Salivary glands are a classic model of organ development and differentiation. Miniature pigs are considered as a unique animal model for salivary gland researchers in the fields of gene transfer, radiation damage, and functional reconstruction. However, there is little information about the development of miniature pig salivary glands. The present article was designed to study the developmental stages of salivary glands in miniature pigs using histological and ultrastructural methods. Sections from E40, E60, E80, E95 embryos, and P0 pups were stained with hematoxylin–eosin, Alcian blue, or periodic acid‐schiff. Selected specimens were also processed for electron microscopy. The development of the miniature pig salivary glands can be divided into five different stages that refer to the stages of the developing mouse submandibular gland. The histological characteristics of the miniature pig salivary glands at different developmental stages were synchronously verified at the ultrastructural level. Interestingly, the development of the miniature pig parotid gland trailed that of the submandibular gland by ～15 days. Our study provides first‐hand data regarding the morphological organogenesis of salivary glands in the miniature pig and provides a foundation for further research on this model. Anat Rec 293:1227–1239, 2010. © 2010 Wiley‐Liss, Inc.     

In vivo investigation of cardiac metabolism in the rat using MRS of hyperpolarized [1‐13C] and [2‐13C]pyruvate

Hyperpolarized ¹³C MRS allows the in vivo assessment of pyruvate dehydrogenase complex (PDC) flux, which converts pyruvate to acetyl‐coenzyme A (acetyl‐CoA). [1‐¹³C]pyruvate has been used to measure changes in cardiac PDC flux, with demonstrated increase in ¹³C‐bicarbonate production after dichloroacetate (DCA) administration. With [1‐¹³C]pyruvate, the ¹³C label is released as ¹³CO₂/¹³C‐bicarbonate, and, hence, does not allow us to follow the fate of acetyl‐CoA. Pyruvate labeled in the C₂ position has been used to track the ¹³C label into the TCA (tricarboxylic acid) cycle and measure [5‐¹³C]glutamate as well as study changes in [1‐¹³C]acetylcarnitine with DCA and dobutamine. This work investigates changes in the metabolic fate of acetyl‐CoA in response to metabolic interventions of DCA‐induced increased PDC flux in the fed and fasted state, and increased cardiac workload with dobutamine in vivo in rat heart at two different pyruvate doses. DCA led to a modest increase in the ¹³C labeling of [5‐¹³C]glutamate, and a considerable increase in [1‐¹³C]acetylcarnitine and [1,3‐¹³C]acetoacetate peaks. Dobutamine resulted in an increased labeling of [2‐¹³C]lactate, [2‐¹³C]alanine and [5‐¹³C]glutamate. The change in glutamate with dobutamine was observed using a high pyruvate dose but not with a low dose. The relative changes in the different metabolic products provide information about the relationship between PDC‐mediated oxidation of pyruvate and its subsequent incorporation into the TCA cycle compared with other metabolic pathways. Using a high dose of pyruvate may provide an improved ability to observe changes in glutamate. Copyright © 2013 John Wiley & Sons, Ltd.     

A 13C NMR study on fluxes into the Krebs cycle of rabbit renal proximal tubular cells

Suspensions of rabbit renal proximal tubular (PCT) cells were incubated with [2-13C] and [3-13C]pyruvate. The perchloric acid extracts of the cell pellets were examined by 13C NMR. All experiments showed that enriched lactate, alanine, glutamate, and glutamine were the main metabolic intermediates, and that enrichment to a minor extent was found in the glutamate residue of glutathione (GSH). From these experiments, it could be deduced that PCT cells show a highly glycolytic activity, whereas enrichment of glucose exhibits gluconeogenesis. The estimation by 13C NMR of the ratio of the flux into the Krebs cycle via pyruvate carboxylase to the flux via pyruvate dehydrogenase is discussed. From incubations with 10 mM 13C-labelled pyruvate, we calculated from the relative enrichments of the glutamate carbon atoms that the ratio of pyruvate carboxylase to pyruvate dehydrogenase is 1.44 +/- 0.04 in rabbit renal proximal tubules.     

Probing the cardiac malate–aspartate shuttle non‐invasively using hyperpolarized [1,2‐13C2]pyruvate

Previous studies have demonstrated that using hyperpolarized [2‐¹³C]pyruvate as a contrast agent can reveal ¹³C signals from metabolites associated with the tricarboxylic acid (TCA) cycle. However, the metabolites detectable from TCA cycle‐mediated oxidation of [2‐¹³C]pyruvate are the result of several metabolic steps. In the instance of the [5‐¹³C]glutamate signal, the amplitude can be modulated by changes to the rates of pyruvate dehydrogenase (PDH) flux, TCA cycle flux and metabolite pool size. Also key is the malate–aspartate shuttle, which facilitates the transport of cytosolic reducing equivalents into the mitochondria for oxidation via the malate–α‐ketoglutarate transporter, a process coupled to the exchange of cytosolic malate for mitochondrial α‐ketoglutarate. In this study, we investigated the mechanism driving the observed changes to hyperpolarized [2‐¹³C]pyruvate metabolism. Using hyperpolarized [1,2‐¹³C]pyruvate with magnetic resonance spectroscopy (MRS) in the porcine heart with different workloads, it was possible to probe ¹³C–glutamate labeling relative to rates of cytosolic metabolism, PDH flux and TCA cycle turnover in a single experiment non‐invasively. Via the [1‐¹³C]pyruvate label, we observed more than a five‐fold increase in the cytosolic conversion of pyruvate to [1‐¹³C]lactate and [1‐¹³C]alanine with higher workload. ¹³C–Bicarbonate production by PDH was increased by a factor of 2.2. Cardiac cine imaging measured a two‐fold increase in cardiac output, which is known to couple to TCA cycle turnover. Via the [2‐¹³C]pyruvate label, we observed that ¹³C–acetylcarnitine production increased 2.5‐fold in proportion to the ¹³C–bicarbonate signal, whereas the ¹³C–glutamate metabolic flux remained constant on adrenergic activation. Thus, the ¹³C–glutamate signal relative to the amount of ¹³C–labeled acetyl‐coenzyme A (acetyl‐CoA) entering the TCA cycle was decreased by 40%. The data strongly suggest that NADH (reduced form of nicotinamide adenine dinucleotide) shuttling from the cytosol to the mitochondria via the malate–aspartate shuttle is limited on adrenergic activation. Changes in [5‐¹³C]glutamate production from [2‐¹³C]pyruvate may play an important future role in non‐invasive myocardial assessment in patients with cardiovascular diseases, but careful interpretation of the results is required.     

Pleomorphic adenoma and carcinoma ex pleomorphic adenoma: immunohistochemical demonstration of the association between tenascin expression and malignancy

AIMS: To investigate tenascin expression in salivary gland tumours. Tenascin is a matricellular protein that has been studied in several tumour types. Its expression has been correlated with tumour morphogenesis as well as with local invasiveness and tumour metastatic behaviour. METHODS AND RESULTS: The distribution pattern of tenascin in a series of 63 pleomorphic adenomas (PA) and 20 carcinomas ex- pleomorphic adenoma (Ca ex PA) was studied immunohistochemically. Ten normal adult salivary glands were used as controls. Tenascin surrounded the excretory ducts of normal adult salivary gland tissue. It was absent in the basement membrane compartment of both benign and malignant mixed tumours. In the interstitial compartment of the extracellular matrix, the fibro-hyaline type expressed tenascin in a statistically significantly (P < 0.001) lower number of PA cases (25%) in comparison with both malignant and benign areas of Ca ex PA (75% and 90%, respectively). In the Ca ex PA group, a statistically significantly difference (P < 0.001) was found in the frequency of tenascin deposits around aggregates of neoplastic cells between metastasizing (73%) and non-metastasizing neoplasms (0%). CONCLUSIONS: These findings strongly support the hypothesis that tenascin deposition is involved in the mechanisms of malignant transformation of pleomorphic adenomas into carcinomas as well as being associated with clinical disease progression.     

MUC1 and MUC2 expression in salivary gland tumors and in non-neoplastic salivary gland tissue

The expression of MUC1 and MUC2 was studied in salivary gland tumors and non-neoplastic salivary gland tissue. Formalin-fixed paraffin-embedded specimens from 101 patients (21 pleomorphic adenomas (PA), 22 Warthin's tumors (WT), 26 adenoid cystic carcinomas (ACC), 13 acinic cell adenocarcinomas (ACA), 9 mucoepidermoid carcinomas (MC), and 10 specimens of non-neoplastic parotid and submandibular gland tissue) were immunostained. All salivary gland tumors expressed MUC1. A strong immunoreactivity was noted in WT and MC, a moderate in ACC and ACA, and a weak in PA. Strong expression of MUC2 was noted in all WT, moderate expression in MC, and weak expression in PA and ACA. All cases of ACC except for two were negative for MUC2. In general, MUC1 expression was stronger than that of MUC2. Non-neoplastic salivary gland tissue revealed a moderate MUC1 and MUC2 expression in excretory ducts and a strong expression in striated ducts. The apical plasma membrane of some serous acini expressed MUC1. Mucous acini were negative for both antigens. No change in immunoreactivity was noted in cases of chronic sclerosing sialadenitis. In conclusion, the different expression pattern of MUC1 and MUC2 in salivary gland neoplasia may be of additional value for the classification of salivary gland tumors.     

In vitro three‐dimensional culture systems of salivary glands

Dry mouth can be caused by salivary gland hypofunction due to Sjögren's syndrome (SS) or radiation therapy for head and neck cancer, and it can also be a side effect of medications. The use of sialagogues effectively increases saliva secretion in patients with dry mouth. However, the application of sialagogues is not always satisfactory because of their side effects, such as sweating, nausea, runny nose and diarrhea. Two‐dimensional (2D) cell cultures have been used not only for drug screening and discovery but also to clarify disease mechanisms. However, three‐dimensional (3D) cell cultures are expected to be even more advantageous than 2D cell cultures. Therefore, we have tried to develop an in vitro cell culture system that can reconstitute 3D salivary glands. Sox9 and Foxc1 were identified as important genes that differentiate mouse embryonic stem cell‐derived oral ectoderm into salivary gland placode. Using these genes and organoid culture systems, we succeeded in generating salivary gland organoids that exhibited a morphology and gene expression profile that were similar to those of the embryonic rudiment from which salivary glands arise in normal mice. These organoids are expected to be a promising tool for disease modeling, drug discovery and regenerative medicine in salivary glands.     

Expression patterns of tight junction proteins in porcine major salivary glands: a comparison study with human and murine glands

Tight junction (TJ) proteins play a dynamic role in paracellular fluid transport in salivary gland epithelia. Most TJ studies are carried out in mice and rats. However, the morphology of rodent salivary glands differs from that of human glands. This study aimed to compare the histological features and the expression pattern of TJ proteins in porcine salivary glands with those of human and mouse. The results showed that porcine parotid glands were pure serous glands. Submandibular glands (SMGs) were serous acinar cell‐predominated mixed glands, whereas sublingual glands were mucous acinar cell‐predominated. Human SMGs were mixed glands containing fewer mucous cells than porcine SMGs, whereas the acinar cells of murine SMGs are seromucous. The histological features of the duct system in the porcine and human SMGs were similar and included intercalated, striated and excretory ducts, but the murine SMG contained a specific structure, the granular convoluted tubule. TJ proteins, including claudin‐1 to claudin‐12, occludin and zonula occludin‐1 (ZO‐1), were detected in the porcine major salivary glands and human SMGs by RT‐PCR; however, claudin‐6, claudin‐9 and claudin‐11 were not detected in the murine SMG. As shown by immunofluorescence, claudin‐1, claudin‐3, claudin‐4, occludin and ZO‐1 were distributed in both acinar and ductal cells in the porcine and human SMGs, whereas claudin‐1 and claudin‐3 were mainly present in acinar cells, and claudin‐4 was mainly distributed in ductal cells in the murine SMG. In addition, 3D images showed that the TJ proteins arranged in a honeycomb‐like structure on the luminal surface of the ducts, whereas their arrangements in acini were irregular in porcine SMGs. In summary, the expression pattern of TJ proteins in salivary glands is similar between human and miniature pig, which may be a candidate animal for studies on salivary gland TJ function.     

Rat salivary gland ligation causes reversible secretory hypofunction

Aim: To determine the influence of inflammation on salivary secretion. Secretion by salivary glands involves interactions between nerves, blood vessels and salivary cells. The present study investigated the effects of inflammation on rat submandibular gland function following acute ductal obstruction. Methods: Under recovery anaesthesia a metal clip was placed on the main duct of the submandibular gland. After 24 h salivary secretion was evoked by nerve and methacholine stimulation. For recovery experiments the clip was removed after 24 h and the animal left to recover for 3 days when salivary function was again assessed. Results: By 24 h of obstruction an inflammatory infiltrate had developed within the obstructed gland and stimulated salivary flows were just 20% of the normal secretion, whilst protein secretion and ion reabsorption were also severely impaired. If ductal obstruction was removed after 24 h the salivary function returned to normal after 3 days of recovery. In vitro analysis of cells from 24‐h ligated glands revealed normal changes in intracellular calcium (the main secondary messenger involved in fluid secretion) in response to methacholine stimulation. Protein secretion from isolated cells indicated some changes in particular to methacholine‐induced protein secretion although a significant protein secretion was still seen in response to isoprenaline – the main stimulus for protein secretion. Conclusion: This report demonstrates reversible salivary inhibition associated with an inflammatory infiltrate within the salivary gland.     

鼻咽癌IMRT前后唾液腺功能变化及与受照剂量的关系

目的:探讨鼻咽癌患者调强放射治疗（IMRT）前后唾液腺的功能变化及与受照剂量的关系。方法:选取广西医科大学第一附属医院接受IMRT初治鼻咽癌患者30例为研究对象,在放疗前、放疗后3个月采用99mTcO4-SPECT唾液腺动态显像测定腮腺、颌下腺的时间-放射性曲线（TAC）、最大浓聚率（MAR）和酸刺激最大分泌率（MSR）,研究唾液腺的功能变化及与受照剂量的关系。结果:放疗后3个月出现1~2级口干症状,腮腺、颌下腺TAC曲线主要表现为轻中度受损,口干程度、TAC曲线与唾液腺受照剂量正相关。放疗后3个月较放疗前腮腺MAR、MSR和颌下腺MSR明显减低（P<0.05）,而颌下腺的MAR无减低（P>0.05）,但两组唾液腺的MAR、MSR对比差异无统计学意义（P>0.05）,两组唾液腺照射剂量均合理。结论:鼻咽癌患者IMRT后出现唾液腺摄取和排泄功能轻中度受损,引起1~2级口干,IMRT能够将唾液腺的受照射剂量控制在合理范围内。     

Cytological features of carcinoma ex pleomorphic adenoma of the salivary glands: A diagnostic challenge

Carcinoma ex pleomorphic adenoma (CXPA) of the salivary glands is a relatively rare carcinoma. The detection rate of the carcinoma component in the cytological specimens is not high and may be challenging in cytological examination. The purpose of the present study was to analyze the cytological specimens of CXPA with emphasis on the detection of the carcinoma component. We reviewed the cytological characteristics of patients histopathologically diagnosed with CXPA who underwent preoperative cytological examination. Of the 10 patients enrolled in the study, 8 had tumors located in the parotid gland, and 2 in the submandibular gland. A review of the cytological specimens revealed the presence of the carcinoma component in all 10 cases and the pleomorphic adenoma (PA) component in 6 cases, although initial cytodiagnosis detected the carcinoma component in 8 cases. The cytological feature of this component was the presence of variable‐sized clusters of polygonal cells with relatively rich cytoplasm and large round to oval nuclei in a necrotic background. Interestingly, carcinoma cells mixed with the PA component were also present. On histopathological analysis, 7 cases were intracapsular, and the remaining 3 cases were widely invasive CXPA. Further, 9 cases had salivary duct carcinoma as carcinoma component. In conclusion, these findings show that careful detection of the carcinoma cells, particularly within the PA component, is crucial for early detection of CXPA, and the presence of necrosis might help with the detection of the carcinoma component.     

Metabolism of hyperpolarized [1‐13C]pyruvate through alternate pathways in rat liver

The source of hyperpolarized (HP) [¹³C]bicarbonate in the liver during metabolism of HP [1‐¹³C]pyruvate is uncertain and likely changes with physiology. Multiple processes including decarboxylation through pyruvate dehydrogenase or pyruvate carboxylase followed by subsequent decarboxylation via phosphoenolpyruvate carboxykinase (gluconeogenesis) could play a role. Here we tested which metabolic fate of pyruvate contributed to the appearance of HP [¹³C]bicarbonate during metabolism of HP [1‐¹³C]pyruvate by the liver in rats after 21 h of fasting compared to rats with free access to food. The ¹³C NMR of HP [¹³C]bicarbonate was observed in the liver of fed rats, but not in fasted rats where pyruvate carboxylation and gluconeogenesis was active. To further explore the relative fluxes through pyruvate carboxylase versus pyruvate dehydrogenase in the liver under typical conditions of hyperpolarization studies, separate parallel experiments were performed with rats given non‐hyperpolarized [2,3‐¹³C]pyruvate. ¹³C NMR analysis of glutamate isolated from the liver of rats revealed that flux from injected pyruvate through pyruvate dehydrogenase was dominant under fed conditions whereas flux through pyruvate carboxylase dominated under fasted conditions. The NMR signal of HP [¹³C]bicarbonate does not parallel pyruvate carboxylase activity followed by subsequent decarboxylation reaction leading to glucose production. In the liver of healthy well‐fed rats, the appearance of HP [¹³C]bicarbonate exclusively reflects decarboxylation of HP [1‐¹³C]pyruvate via pyruvate dehydrogenase. © 2016 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.