Distribution of the glutamate transporters GLT-1 (SLC1A2) and GLAST (SLC1A3) in peripheral organs

The glutamate transporters GLT-1 and GLAST are widely expressed in astrocytes in the brain where they fulfill important functions during glutamatergic neurotransmission. The present study examines their distribution in peripheral organs using in situ hybridization (ISH) and immunocytochemistry. GLAST was found to be more widely distributed than GLT-1. GLAST was expressed primarily in epithelial cells, cells of the macrophage-lineage, lymphocytes, fat cells, interstitial cells, and salivary gland acini. GLT-1 was primarily expressed in glandular tissue, including mammary gland, lacrimal gland, and ducts and acini in salivary glands, but also by perivenous hepatocytes and follicular dendritic cells in spleen and lymph nodes. The findings demonstrate that, although expressed by the same cells in the brain, these two glutamate transporters have different distribution patterns in peripheral tissues and that they fulfill glutamate transport functions apart from glutamatergic neurotransmission in these areas.

Low social support and poor emotional regulation are associated with increased stress hormone reactivity to mental stress in systemic hypertension

CONTEXT: There is strong evidence for a physiological hyperreactivity to stress in systemic hypertension, but data on associated or potentially moderating psychological factors are scarce. OBJECTIVE: The objective of the study was to identify psychological correlates of physiological stress reactivity in systemic hypertension. DESIGN: This was a cross-sectional, quasi-experimentally controlled study. Study participants underwent an acute standardized psychosocial stress task combining public speaking and mental arithmetic in front of an audience. SETTING: The study was conducted in the population in the state of Zurich, Switzerland. SUBJECTS: Subjects included 22 hypertensive and 26 normotensive men (mean +/- sem 44 +/- 2 yr). MAIN OUTCOME MEASURES: We assessed the psychological measures social support, emotional regulation, and cognitive appraisal of the stressful situation. Moreover, we measured salivary cortisol and plasma epinephrine and norepinephrine before and after stress and several times up to 60 min thereafter as well as blood pressure and heart rate. RESULTS: We found poorer hedonistic emotional regulation (HER) and lower perceived social support in hypertensives, compared with normotensives (P < 0.01). Compared with normotensives, hypertensives showed higher cortisol, epinephrine, and norepinephrine secretions after stress (P < 0.038) as well as higher systolic and diastolic blood pressure (P < 0.001). Cortisol reactivity and norepinephrine secretion were highest in hypertensive men with low HER (P < 0.05). In contrast, hypertensives with high HER did not significantly differ from normotensives in both cortisol and norepinephrine secretion after stress. Epinephrine secretion was highest in hypertensives with low social support but was not different between hypertensives with high social support and normotensives. CONCLUSIONS: The findings suggest that both low social support and low HER are associated with elevated stress hormone reactivity in systemic hypertension.

Fruit yogurt: any erosive potential regarding teeth?

OBJECTIVE: The capability of drinks and foods to resist pH changes brought about by salivary buffering may play an important role in the dental erosion process in children. The aim of the present study was to test fruit yogurt, a popular snack for children, and the degrees of saturation (pK-pl) with respect to hydroxyapatite and fluorapatite to determine their erosive potential. METHOD AND MATERIALS: A variety of fruit yogurt was tested. To test the pH, 8 readings were taken with a pH electrode for each yogurt. Calcium content was detected by atomic absorption spectrophotometer, phosphorus by the inductively coupled plasma method, and fluoride content by ion chromatography. The degrees of saturation of hydroxyapatite and fluorapatite were calculated by use of a computer program. Statistical analysis was performed using 2-tailed analysis of variance (P < .05) and a post hoc test (Tukey) to determine differences between groups. RESULTS: The pH of each fruit concentrate was significantly different, except for banana yogurt. Except for the phosphorus content of raspberry yogurt, the calcium and phosphorus content for each fruit concentrate were significantly different. Fluoride levels were the same for all yogurts tested, and the degrees of saturation of hydroxyapatite and fluorapatite was positive, indicating supersaturation. CONCLUSION: It could be stated that fruit yogurt has no erosive potential.

Risk assessment and preventive measures

A prerequisite for preventive measures is to diagnose erosive tooth wear and to evaluate the different etiological factors in order to identify persons at risk. No diagnostic device is available for the assessment of erosive defects. Thus, they can only be detected clinically. Consequently, erosion not diagnosed in the early stage may render timely preventive measures difficult. In order to assess the risk factors, patient should record their dietary intake for a distinct period of time. Then a dentist can determine the erosive potential of the diet. Particularly, patients with more than four dietary acid intakes have a higher risk for erosion when other risk factors (such as holding the drink in the mouth) are present. Regurgitation of gastric acids (reflux, vomiting, alcohol abuse, etc.) is a further important risk factor for the development of erosion which has to be taken into account. Based on these analyses, an individually tailored preventive program may be suggested to the patients. It may comprise dietary advice, optimization of fluoride regimes, stimulation of salivary flow rate, use of buffering medicaments and particular motivation for nondestructive toothbrushing habits with a low abrasive toothpaste. The frequent use of fluoride gel and fluoride solution in addition to fluoride toothpaste offers the opportunity to reduce somewhat abrasion of tooth substance. It is also advisable to avoid abrasive tooth cleaning and whitening products, since they may remove the pellicle and may render teeth more susceptible to erosion. Since erosion, attrition and abrasion often occur simultaneously all causative components must be taken into consideration when planning preventive strategies.

Extrinsic causes of erosion. Biological factors

Biological factors such as saliva, acquired dental pellicle, tooth structure and positioning in relation to soft tissues and tongue are related to dental erosion development. Saliva has been shown to be the most important biological factor in the prevention of dental erosion. It starts acting even before the acid attack, with the increase of the salivary flow rate as a response to the acidic stimuli. This creates a favorable scenario, increasing the buffering system of saliva and effectively diluting and clearing acids on dental surfaces during the erosive challenge. Saliva plays a role in the formation of the acquired dental pellicle, which acts as a perm-selective membrane preventing contact of the acid with the tooth surf aces. The protective level of the pellicle seems to be regulated by its composition, thickness and maturation time. Due to its mineral content, saliva can also prevent demineralization as well as enhance remineralization. However, these preventive and reparative factors of saliva may not be enough against highly erosive challenges, leading to erosion development. The progress rate of erosion can be significantly influenced by the type of dental substrate, occurrence of mechanical and chemical attacks, fluoride exposure, and also by contact with the oral soft tissues and tongue.

Extrinsic causes of erosion. Oral hygiene products and acidic medicines

Acidic or EDTA-containing oral hygiene products and acidic medicines have the potential to soften dental hard tissues. The low pH of oral care products increases the chemical stability of some fluoride compounds, favors the incorporation of fluoride ions in the lattice of hydroxyapatite and the precipitation of calcium fluoride on the tooth surface. This layer has some protective effect against an erosive attack. However, when the pH is too low or when no fluoride is present these protecting effects are replaced by direct softening of the tooth surface. Xerostomia or oral dryness can occur as a consequence of medication such as tranquilizers, anti-histamines, anti-emetics and anti-parkinsonian medicaments or of salivary gland dysfunction e.g. due to radiotherapy of the oral cavity and the head and neck region. Above all, these patients should be aware of the potential demineralization effects of oral hygiene products with low pH and high titratable acids. Acetyl salicylic acid taken regularly in the form of multiple chewable tablets or in the form of headache powder as well chewing hydrochloric acids tablets for treatment of stomach disorders can cause erosion. There is most probably no direct association between asthmatic drugs and erosion on the population level. Consumers, patients and health professionals should be aware of the potential of tooth damage not only by oral hygiene products and salivary substitutes but also by chewable and effervescent tablets. Additionally, it can be assumed that patients suffering from xerostomia should be aware of the potential effects of oral hygiene products with low pH and high titratable acids.

Extrinsic causes of erosion. Behavioral factors

During and after an erosive challenge, behavioral factors play a role in modifying the extent of erosive tooth wear. The manner that dietary acids are introduced into the mouth (gulping, sipping, use of a straw) will affect how long the teeth are in contact with the erosive challenge. The frequency and duration of exposure to an erosive agent is of paramount importance. Night-time exposure (e.g. baby bottle-feeding) to erosive agents may be particularly destructive because of the absence of salivary flow. Health-conscious individuals tend to ingest acidic drinks and juices more frequently and tend to have higher than average oral hygiene. While good oral hygiene is of proven value in the prevention of periodontal disease and dental caries, frequent toothbrushing with abrasive oral hygiene products may enhance erosive tooth wear. Unhealthy lifestyles such as consumption of designer drugs, alcopops and alcohol abuse are other important behavioral factors.

Erosive and buffering capacities of yogurt

OBJECTIVE: The capability of drinks and foods to resist pH changes brought about by salivary buffering may play an important role in the erosion of dental enamel. The aim of the present study was to measure the initial pH of several types of yogurt and to test the degrees of saturation (pK-pl) with respect to hydroxyapatite and fluorapatite to determine the buffering capacity and related erosive potential of yogurt. METHOD AND MATERIALS: Twenty-five milliliters of 7 types of freshly opened yogurt was titrated with 1 mol/L of sodium hydroxide, added in 0.5 mL increments, until the pH reached 10, to assess the total titratable acidity, a measure of the drink's own buffering capacity. The degrees of saturation (pK-pl) with respect to hydroxyapatite and fluorapatite were also calculated, using a computer program developed for this purpose. For statistical analysis, samples were compared using Kruskal-Wallis test. RESULTS: The buffering capacities can be ordered as follows: fruit yogurt >low-fat yogurt >bioyogurt >butter yogurt >natural yogurt >light fruit yogurt >light yogurt. The results suggest that, in vitro, fruit yogurt has the greatest buffering capacity. CONCLUSION: It can be stated that it is not possible to induce erosion on enamel with any type of yogurt.

Pleomorphic adenoma of the parotid gland: histopathologic analysis of the capsular characteristics of 218 tumors

BACKGROUND: Histopathologic features of the capsule may have an impact on the recurrence rate of pleomorphic adenomas. METHODS: Retrospective (n = 154) and prospective (n = 64) histologic analysis of the capsular characteristics such as incompleteness, tumor penetration, pseudopodia, and satellite tumors of 218 pleomorphic adenomas. RESULTS: In 160 of the 218 (73%) pleomorphic adenomas, 1 or more capsular characteristics such as incomplete capsule (33%), capsule penetration (26%), pseudopodia (40%), and satellite nodules (13%) were detected. Incomplete capsule and satellite tumors were most frequently seen in the stroma-rich (myxoid) subtype. Capsular penetration and pseudopodia were significantly more common in the prospective group than in the retrospective group (p < .05/<.05). CONCLUSION: Pseudopodia and satellite tumors were more common than reported in the literature. If left in the surrounding salivary gland tissue at surgery, they can lead to recurrences of pleomorphic adenomas of the parotid gland.

Pleomorphic adenoma in an atypical location near the temporomandibular joint: a case report

Pleomorphic adenomas primarily arise in the major salivary glands, especially in the parotid. The most common area is the lower pole superficial to the plane of the facial nerve. In this report, a pleomorphic adenoma in an atypical location--the region of the temporomandibular joint (TMJ)--is presented. The tumor was solitary, closely attached to the capsule of the TMJ and superior to the parotid gland, with clear demarcation. Clinically, the tumor resembled TMJ pathology, but MRI examination led to diagnosis of a benign tumor attached to the TMJ. This report shows that pleomorphic adenoma can be a possible diagnosis for lesions at the joint capsule.

A family of stage-specific alanine-rich proteins on the surface of epimastigote forms of Trypanosoma brucei

A 'two coat' model of the life cycle of Trypanosoma brucei has prevailed for more than 15 years. Metacyclic forms transmitted by infected tsetse flies and mammalian bloodstream forms are covered by variant surface glycoproteins. All other life cycle stages were believed to have a procyclin coat, until it was shown recently that epimastigote forms in tsetse salivary glands express procyclin mRNAs without translating them. As epimastigote forms cannot be cultured, a procedure was devised to compare the transcriptomes of parasites in different fly tissues. Transcripts encoding a family of glycosylphosphatidyl inositol-anchored proteins, BARPs (previously called bloodstream alanine-rich proteins), were 20-fold more abundant in salivary gland than midgut (procyclic) trypanosomes. Anti-BARP antisera reacted strongly and exclusively with salivary gland parasites and a BARP 3' flanking region directed epimastigote-specific expression of reporter genes in the fly, but inhibited expression in bloodstream and procyclic forms. In contrast to an earlier report, we could not detect BARPs in bloodstream forms. We propose that BARPs form a stage-specific coat for epimastigote forms and suggest renaming them brucei alanine-rich proteins.

Tissue-dependent subcellular localization of Drosophila arginine methyl-transferase 4 (DART4), a coactivator whose overexpression affects neither viability nor differentiation

Drosophila arginine methyl-transferase 4 (DART4) belongs to the type I class of arginine methyltransferases. It catalyzes the methylation of arginine residues to monomethylarginines and asymmetrical dimethylarginines. The DART4 sequence is highly similar to mammalian PRMT4/CARM1, and DART4 substrate specificity has been conserved, too. Recently it was suggested that DART4/Carmer functions in ecdysone receptor mediated apoptosis of the polytene larval salivary glands and an apparent up-regulation of DART4/Carmer mRNA levels before tissue histolysis was reported. Here we show that in Drosophila larvae, DART4 is mainly expressed in the imaginal disks and in larval brains, and to a much lesser degree in the polytene larval tissue such as salivary glands. In glands, DART4 protein is present in the cytoplasm and the nucleus. The nuclear signal emanates from the extrachromosomal domain and gets progressively restricted to the region of the nuclear lamina upon pupariation. Surprisingly, DART4 levels do not increase in salivary glands during pupariation, and overexpression of DART4 does not cause precautious cell death in the glands. Furthermore, over- and misexpression of DART4 under the control of the alpha tubulin promoter do not lead to any major problem in the life of a fly. This suggests that DART4 activity is regulated at the posttranslational level and/or that it acts as a true cofactor in vivo. We present evidence that nuclear localization of DART4 may contribute to its function because DART4 accumulation changes from a distribution with a strong cytoplasmic component during the transcriptional quiescence of the young embryo to a predominantly nuclear one at the onset of zygotic transcription.

Nasal acinic cell carcinoma in a cat

This case report describes the clinical, magnetic resonance imaging (MRI)-related, and pathologic features of a nasal acinic cell carcinoma in a cat. A 16-year-old, castrated male, oriental shorthaired cat, weighing 3.8 kg, was presented with history of sneezing, coughing, and nasal discharge persisting several months. Evaluation by MRI revealed an heterogeneous, space-occupying lesion that filled the left nasal cavity and was diagnosed by histopathologic examination as an acinic cell carcinoma arising from a minor salivary gland of the nasal cavity. Acinic cell carcinoma is a rare tumor in veterinary medicine. The tumor is composed mainly of cells resembling serous cells of salivary glands and originates from major or minor salivary glands. Clinicians and pathologists should be aware of the occurrence of acinic cell carcinoma in the sinonasal tract and include the tumor in the differential diagnosis of feline nasal diseases.