A Stimulator of the Salivary Excretion Based on Physical Vibration of the Parotid Glands.

Oral dryness causes significant health problems both functional (difficulty speaking, chewing and swallowing) and structural in teeth (increased number of infections) and oral mucosa. The main objective of this study is to show an alternative treatment to help stimulate the salivary secretion thus improving the quality of life of the patient. In this study, a salivary stimulation equipment using vibrotactile stimuli is shown. The system has been placed bilaterally in the parotid glands and assessed the efficacy of the salivary secretion by sialometry before and after the stimulation. The new proposal is capable of stimulating salivary secretion, in a significative way after 7 minutes of use, at least in the cases analyzed, and fulfills low-cost, easy-to-use, and safe technical restrictions. In this setting, this paper suggests the performance of a deep clinical trial to measure the exact efficacy of the prototype and the times and frequencies needed to state the optimal treatment depending in each case.

Long non-coding RNA and mRNA profile analysis in the parotid gland of mouse with type 2 diabetes.

AIMS: Salivary gland dysfunction is a common complication of diabetes mellitus (DM). Long non-coding RNA (lncRNA) is evidenced to involve in the functional regulation of salivary gland, however, its role in DM-impaired gland is unknown. Therefore, this study aimed to investigate the expression profiles and functional networks of lncRNA in the parotid glands (PGs) of DM mice. MAIN METHODS: Microarray was used to detect lncRNA and messenger RNA (mRNA) expression profiles in the PGs from db/db and db/m mice. Eleven differently expressed (DE) lncRNAs validated by qRT-PCR were selected for coding-non-coding gene co-expression (CNC) and competing endogenous RNA (ceRNA) network analysis, as well as the following Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Pearson's coefficient correlation analysis was used to analyze the correlations between DE lncRNAs expression and DM pathology. KEY FINDINGS: By using a 2-fold change and P < 0.05 as the cutoff criteria, 1650 DE lncRNAs (758 upregulated and 892 downregulated) and 1073 mRNAs (563 upregulated and 510 downregulated) were identified in the PGs of db/db mice compared to db/m mice. GO and KEGG analysis of DE mRNA suggested that activated inflammation response and downregulated ion transport might count for the dysfunction of diabetic PG. CNC and ceRNA networks analysis of 11 DE lncRNAs showed that the inflammation process and its related signaling pathways including advanced glycation end product (AGE)-receptor for AGE (RAGE) signaling pathway in diabetic complications, cytokine-cytokine receptor interaction, chemokine signaling pathway, apoptosis, and cell adhesion molecules were significantly enriched. The alterations of lncRNAs were closely correlated with higher blood glucose and serum insulin levels in mice. SIGNIFICANCE: We identified multiple lncRNAs/mRNAs and several signaling pathways that may involve in the pathogenesis of diabetic salivary injury, providing new insight into potential target of diabetic hyposalivation.

Variation in size and shape of toxin glands among cane toads from native-range and invasive populations.

If optimal investment in anti-predator defences depends on predation risk, invading new regions (and thus, encountering different predators) may favour shifts in that investment. Cane toads offer an ideal system to test this prediction: expensive anti-predator toxins are stored mainly in parotoid glands whose dimensions are easy to measure, and toad invasions have changed the suites of predators they encounter. Although plasticity may influence parotoid morphology, comparisons between parents and progeny revealed that gland dimensions were highly heritable. That heritability supports the plausibility of an evolved basis to variation in gland dimensions. Measurements of 3779 adult toads show that females have larger glands than males, invasive populations have larger glands than in the native-range, and that parotoid sexual size dimorphism varies strongly among invaded areas. Geographic variation in parotoid morphology may be driven by predation risk to both adult toads and offspring (provisioned with toxins by their mother), with toxins allocated to eggs exacerbating the risk of cannibalism but reducing the risk of interspecific predation. Investment into chemical defences has evolved rapidly during the cane toad's international diaspora, consistent with the hypothesis that organisms flexibly adjust resource allocation to anti-predator tactics in response to novel challenges.

Individual variation in cardiotoxicity of parotoid secretion of the common toad, Bufo bufo, depends on body size - first results.

Anurans secrete a wide diversity of toxins from skin glands to defend themselves against predators and pathogens. Bufonids produce potent poison in parotoid macroglands located in the postorbital region. Parotoid secretion is a rich source of bioactive compounds with cardiotoxic, cytotoxic and hemolytic activity. Poison content and toxicity may vary between species, populations, and among conspecifics inhabiting the same area. In the present paper, we pre-analyzed the individual variation in cardiotoxicity of parotoid extract of common toads (Bufo bufo Linnaeus, 1758) and impact of body mass (BM), snout to vent length (SVL), and body condition (BC) of toad on the poison toxicity. We hypothesized that large toads produce poison with higher cardiotoxicity than smaller ones. Parotoid extract was fractionated by reverse phase chromatography, and then in vitro physiological bioassays were carried out on the semi-isolated hearts of the mealworm beetle (Tenebrio molitor Linnaeus, 1758) to determine cardiotoxicity of the whole poison and separated fractions. Generalized linear mixed models were used to determine effects of BM, SVL, and BC on the poison toxicity. We recorded significant changes in the insect heart contractility after treatment with the whole poison and separated fractions. We found an individual variation in cardiotoxicity of the parotoid extract which was explained by the body size of toad. Poison of smaller toads displayed a negative, whereas poison of larger toads positive, chronotropic effect on the heart contractility. Thus, we conclude that the effectiveness of parotoid secretion in repelling predators may vary depending on the toad individual size.

Chondroitin sulfate isolated from the secretion of the venom-producing parotoid gland of Brazilian bufonid.

The parotoid gland of bufonids is characterized as a specialized integument region, formed by different gland types. The secretion elaborated by the largest glandular alveoli has been related to animal chemical defense and is constituted by granular protein content, associated with a basophilic and alcianophilic material with features of glycoconjugates. This study aimed to identify and characterize the glycoconjugates in the secretion of the largest granular gland of the parotoid gland of Rinella icterica by histochemical and immunohistochemical techniques at light microscopy, biochemical methods, and nuclear magnetic resonance spectroscopy. Our results showed that the glycoconjugate content contains a mixture of chondroitin­6­sulfate (C6S) and chondroitin-non-sulfate (C0S). Thus, chondroitin sulfate probably plays an important role in gland physiology, probably protecting the protein content while inside the secretory portion.

An experimental study of menopause induced by bilateral ovariectomy and mechanistic effects of mesenchymal stromal cell therapy on the parotid gland of a rat model.

The current study was conducted on a menopause rat model induced by ovariectomy to assess the histological and immunohistochemical alterations in the parotid glands and to verify the efficiency of human umbilical cord derived-mesenchymal stromal cell (hUCB-MSCs) in treating this condition. Eighteen adult female rats were equally divided into three groups: sham-operated (SHAM), ovariectomized (OVX) and OVX injected with hUCB-MSCs (OVX+hUCB-MSCs). At 3months post-ovariectomy, the salivary flow rate and size of the parotid glands were measured. The parotid glands were histologically investigated via H&E stained sections. Furthermore, immunohistochemical analysis for human CD105, human CD34, proliferating cell nuclear antigen (PCNA), single strand DNA (ssDNA), caspase 3, aquaporin (AQP)1, α-smooth muscle actin (α-SMA) and mouse CD34 were performed. The OVX group showed interstitial hemorrhage, dispersed acini and intracytoplasmic vacuoles in the acinar cells. Furthermore, immunohistochemical staining revealed a significant decrement in the number of ssDNA positive apoptotic cells, but a significant increment of PCNA positive proliferating cells, AQP1 positive blood capillaries, α-SMA positive myoepithelial cells and endogenous CD34 positive hematopoietic progenitor cells in the OVX+hUCB-MSCs group as compared with the OVX group. These findings suggest a potential regenerative therapy of MSCs to injured parotid gland structures. However, further investigations are required to illustrate the mechanism of hUCB-MSCs mediated parotid gland regeneration.

Acquisition of N-Glycosylation Sites in Immunoglobulin Heavy Chain Genes During Local Expansion in Parotid Salivary Glands of Primary Sjögren Patients.

Previous studies revealed high incidence of acquired N-glycosylation sites acquired N-glycosylation sites in RNA transcripts encoding immunoglobulin heavy variable region (IGHV) 3 genes from parotid glands of primary Sjögren's syndrome (pSS) patients. In this study, next generation sequencing was used to study the extent of ac-Nglycs among clonally expanded cells from all IGVH families in the salivary glands of pSS patients. RNA was isolated from parotid gland biopsies of five pSS patients and five non-pSS sicca controls. IGHV sequences covering all functional IGHV genes were amplified, sequenced, and analyzed. Each biopsy recovered 1,800-4,000 unique IGHV sequences. No difference in IGHV gene usage was observed between pSS and non-pSS sequences. Clonally related sequences with more than 0.3% of the total number of sequences per patient were referred to as dominant clone. Overall, 70 dominant clones were found in pSS biopsies, compared to 15 in non-pSS. No difference in percentage mutation in dominant clone-derived IGHV sequences was seen between pSS and non-pSS. In pSS, no evidence for antigen-driven selection in dominant clones was found. We observed a significantly higher amount of ac-Nglycs among pSS dominant clone-derived sequences compared to non-pSS. Ac-Nglycs were, however, not restricted to dominant clones or IGHV gene. Most ac-Nglycs were detected in the framework 3 region. No stereotypic rheumatoid factor rearrangements were found in dominant clones. Lineage tree analysis showed in four pSS patients, but not in non-pSS, the presence of the germline sequence from a dominant clone. Presence of germline sequence and mutated IGHV sequences in the same dominant clone provide evidence that this clone originated from a naïve B-cell recruited into the parotid gland to expand and differentiate locally into plasma cells. The increased presence of ac-Nglycs in IGHV sequences, due to somatic hypermutation, might provide B-cells an escape mechanism to survive during immune response. We speculate that glycosylation of the B-cell receptor makes the cell sensitive to environmental lectin signals to contribute to aberrant B-cell selection in pSS parotid glands.

Early Changes in Apparent Diffusion Coefficient for Salivary Glands during Radiotherapy for Nasopharyngeal Carcinoma Associated with Xerostomia.

Objective: To evaluate the early changes in the apparent diffusion coefficient (ADC) of the salivary glands during radiotherapy (RT) and their association with the degree of xerostomia at 6 months after RT in patients with nasopharyngeal carcinoma (NPC). Materials and Methods: We enrolled 26 patients with NPC who underwent RT. Each patient underwent diffusion-weighted MRI of the salivary glands at rest and with gustatory stimulation within 1 week before RT and 2 weeks after the beginning of RT. The ADC at rest (ADCR) and increase and increase rate with stimulation (ADCI, ADCIR) of the submandibular and parotid glands were calculated. The differences in the variables' values between 2 weeks after the beginning of RT and baseline (ΔADCR, ΔADCI, and ΔADCIR) were compared to the degree of xerostomia at 6 months after RT. Results: The ADCR of the submandibular and parotid glands were both significantly higher at 2 weeks after the beginning of RT than found at baseline (both p < 0.01). The ADCI and ADCIR for the parotid glands were both significantly lower at 2 weeks after the beginning of RT than found at baseline (both p < 0.01). ΔADCI and ΔADCIR of the parotid glands were associated with the degree of xerostomia at 6 months after RT (r = -0.61 and -0.72, both p < 0.01). Conclusion: The ADCs of the salivary glands change early during RT. The differences in the ADC increase and increase rate of the parotid glands between 2 weeks after the beginning of RT and baseline were associated with the degree of xerostomia at 6 months after RT.

Quantitative Assessment of Thyroid, Submandibular, and Parotid Glands Elasticity With Shear-Wave Elastography in Children.

Tissue elasticity is becoming a more commonly used parameter in evaluation of parenchyma in inflammatory diseases. Considering the changes in the thyroid and salivary glands with adolescence, determination of mean elasticity ranges with a function of age is necessary to apply ultrasound elastography more widely in the pediatric population.The thyroid, submandibular, and parotid glands of 127 healthy volunteers (66 males, 61 females; mean age = 10.3 ± 3.9 years; range = 3-17 years) were evaluated with shear-wave elastography.The mean elasticity values for the thyroid, submandibular, and parotid glands were 14.6 ± 3.3, 11.8 ± 2.2, and 11.8 ± 2.6 kPa, respectively. There was a significant positive correlation between age and elasticity of the thyroid, submandibular, and parotid glands. There was a significant correlation between age and elasticity value of the thyroid gland adjusted for weight and height.This study provided the baseline quantitative elasticity measures of thyroid, submandibular, and parotid glands, which would be a reference for upcoming studies. In addition, an increase in elasticity value in thyroid gland as a function of age independent of change in weight and height was demonstrated.

New saliva secretion model based on the expression of Na+-K+ pump and K+ channels in the apical membrane of parotid acinar cells.

The plasma membrane of parotid acinar cells is functionally divided into apical and basolateral regions. According to the current model, fluid secretion is driven by transepithelial ion gradient, which facilitates water movement by osmosis into the acinar lumen from the interstitium. The osmotic gradient is created by the apical Cl- efflux and the subsequent paracellular Na+ transport. In this model, the Na+-K+ pump is located exclusively in the basolateral membrane and has essential role in salivary secretion, since the driving force for Cl- transport via basolateral Na+-K+-2Cl- cotransport is generated by the Na+-K+ pump. In addition, the continuous electrochemical gradient for Cl- flow during acinar cell stimulation is maintained by the basolateral K+ efflux. However, using a combination of single-cell electrophysiology and Ca2+-imaging, we demonstrate that photolysis of Ca2+ close to the apical membrane of parotid acinar cells triggered significant K+ current, indicating that a substantial amount of K+ is secreted into the lumen during stimulation. Nevertheless, the K+ content of the primary saliva is relatively low, suggesting that K+ might be reabsorbed through the apical membrane. Therefore, we investigated the localization of Na+-K+ pumps in acinar cells. We show that the pumps appear evenly distributed throughout the whole plasma membrane, including the apical pole of the cell. Based on these results, a new mathematical model of salivary fluid secretion is presented, where the pump reabsorbs K+ from and secretes Na+ to the lumen, which can partially supplement the paracellular Na+ pathway.

Quantification of the salivary volume flow rate in the parotid duct using the time-spatial labeling inversion pulse (Time-SLIP) technique at MRI: A feasibility study.

BACKGROUND: We developed a method to quantify the volume flow rate (VFR) using the time-spatial labeling inversion pulse (Time-SLIP) technique to evaluate salivary function. PURPOSE/HYPOTHESIS: To investigate the accuracy of quantification of the salivary VFR using the Time-SLIP technique in phantoms and to examine the feasibility of its use in human subjects. STUDY TYPE: This was a prospective phantom and volunteer study. POPULATION/SUBJECTS/PHANTOM/SPECIMEN/ANIMAL MODEL: A phantom and 23 normal volunteers who fasted at least 2 hours study was performed. FIELD STRENGTH/SEQUENCE: Flow images of the phantom and the parotid duct of 23 volunteers were acquired on a 3T-MRI scanner using the Time-SLIP technique. ASSESSMENT: Hypothesizing that flow aggregates in the conducting duct, we measured the VFR on flow images. In the phantom study, the actual VFR (slow, medium, fast flow) was controlled by an automatic pump system and the measured VFR was compared with the actual VFR on flow images. In the human study we injected citric acid into the mouth of healthy volunteers to stimulate saliva secretion and recorded the VFR. STATISTICAL TESTS: As this study was a feasibility study, statistical tests were not performed. RESULTS: In the phantom study, the VFR at slow, medium, and fast flow was 5.7 ± 0.4 (SD), 8.4 ± 0.3, and 12.2 ± 1.1 mm3 /sec, respectively. The error between the measured and actual VFR values was 2.8-3.7%. Salivary flow in the parotid duct was visualized in 22 of the 23 volunteers. The mean VFR was 8760 mm3 /10 min. DATA CONCLUSION: When salivary flow was stimulated with citric acid in normal volunteers, the salivary VFR could be obtained using the Time-SLIP technique. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:928-935.

Dental microwear textural analysis as an analytical tool to depict individual traits and reconstruct the diet of a primate.

OBJECTIVES: Dental microwear is a promising tool to reconstruct animals' diet because it reflects the interplay between the enamel surface and the food items recently consumed. This study examines the sources of inter-individual variations in dietary habits in a free-ranging population of mandrills (Mandrillus sphinx) using a combination of feeding monitoring and in vivo dental microwear textural analysis (DMTA). METHODS: We investigated the impact of seasonality and individual traits on four DMTA parameters. In parallel, we further studied the influence of the physical properties of the food items consumed on these four parameters, using three proxies (mechanical properties, estimates of phytolith and external grit contents). RESULTS: We found that seasonality, age, and sex all impact DMTA parameters but those results differ depending on the facet analyzed (crushing vs. shearing facets). Three DMTA parameters (anisotropy, complexity, and heterogeneity of complexity) appear sensitive to seasonal variations and anisotropy also differs between the sexes while textural fill volume tends to vary with age. Moreover, the physical properties of the food items consumed vary seasonally and also differ depending on individual sex and age. CONCLUSION: Considering the interplay between the tested variables and both dental microwear and diet, we reaffirm that food physical properties play a major role in microwear variations. These results suggest that DMTA parameters may provide valuable hints for paleoecological reconstruction using fragmentary fossil dental remains.

Digestive and Nondigestive Functions of Rodents' Salivary Glands.

Major salivary glands play a role not only in digestion, but also in regulation of other functions in rodents. In this review, we analyzed and summarized the data about the rodents' parotid, submandibular and sublingual salivary glands functions, which is not limited to the production of saliva and action of its hydrolytic enzymes on food in the oral cavity. In recent decades significantly expanded understanding of major salivary glands nondigestive functions. They are involved in excretion of metabolic products, maintaining fluid and electrolyte balance. Special attention has been paid to the characteristics of specific (parotin, sialorphin, etc.) and nonspecific (epidermal growth factor, nerve growth factor, kallikrein, etc.) active substances of the major salivary glands and their involvement in wound healing, mineral metabolism, regulation of hematopoiesis and immunity system. Summarized and analyzed major salivary glands endocrine function in the organs and systems. Available literature data suggest: the structure of the major salivary glands, as well as the synthesis and secretion of a number of biologically active substances are controlled by sex hormones. In turn, these biologically active factors of the salivary glands, as epidermal growth factor, and parotin, sialorphin, whose expression is regulated by androgens, have an impact on the morphological and functional state of the gonads. Thus, major salivary glands operate a wide range of functions and involved in the regulation of sexual behavior of reproductive function and maintaining homeostasis in the body.

Outpatient versus observation/inpatient parotidectomy: patient factors and perioperative complications.

The objective of this manuscript is to review a single institution's experience with superficial or total parotidectomy in outpatient and observation/inpatient groups. All patients who underwent superficial or total parotidectomy between 2009 and 2015 were identified. Patients were excluded if they had undergone concurrent surgery such as neck dissection, had prior radiation treatment or surgery at the operative site. Main outcomes were perioperative complications in both groups. 215 consecutive patients were included in the study, 116 (54%) patients in the inpatient group and 99 (46%) in the outpatient group. Aside from a higher observed rate of cardiac disease in the outpatient group (24.2 vs. 11.2%, p = 0.014) and larger mean body mass index (BMI) in the inpatient group (32.448 vs. 30.034, p = 0.017), there were no significant differences for age, sex or smoking status. Average operative time differed between groups with 2 h 42 min for inpatients and 2 h 18 min for outpatients (p < 0.001). There were 26 complications in the inpatient group (22.4%, including two hematomas) and 8 in the outpatient group (8.1%). The rate of seroma/sialocele formation was significantly higher in the inpatient group at 15.5% (n = 18) compared with the outpatient group at 3% (n = 3, p = 0.001). Our study shows that parotidectomy, superficial or total, was performed safely as an outpatient procedure without significant increase in complications when compared to patients observed for at least one night after surgery.

Shear wave elastography parameters of normal soft tissues of the neck.

BACKGROUND: Shear wave elastography is a relatively new method of quantitative measurement of tissue elasticity. Assuming that malignant lesions are stiffer than benign ones, elastography may provide supplementary information for their discrimination. However, potential confounding factors impacting tissue stiffness should be investigated first. AIMS: The objective of this study was to measure the stiffness of selected tissues of the head and neck in a normal population and to evaluate its relationship to age, sex, and body mass index. METHODS: Stiffness of the thyroid, submandibular and parotid glands, masseter and sternocleidomastoid muscles, and cervical lymph nodes was measured bilaterally in 128 healthy volunteers (83 female and 45 male). At least 20 subjects in each decade of life (20-29, 30-39‥, 70+) were enrolled. Shear wave elastography was performed by a single radiologist in all the subjects. The stiffnesses obtained were correlated with age, sex, and body mass index. RESULTS: The mean stiffness was 9.5 ± 3.6 kPa for the thyroid, 9.5 ± 4.6 kPa for the lymph node, 11.0 ± 3.4 kPa for the submandibular gland, 9.0 ± 3.5 kPa for the parotid gland, 9.9 ± 4.1 kPa for the sternocleidomastoid, and 10.0 ± 4.3 kPa for the masseter muscle. A slight general decrease in stiffness with increasing age was found. BMI and weight had a small impact on the minimum and maximum stiffness values. The sex of the subject did not affect elasticity. CONCLUSION: The mean stiffness of healthy head and neck organs has a relatively narrow distribution around 11 kPa. The changes of stiffness with age, BMI, and weight that were identified are too small to have clinical impact.

Intravoxel incoherent motion imaging measurement of perfusion changes in the parotid gland provoked by gustatory stimulation: A pilot study.

PURPOSE: To demonstrate the feasibility of intravoxel incoherent motion imaging (IVIM) for quantification of perfusion changes in the parotid gland after gustatory stimulation. MATERIALS AND METHODS: Eight healthy volunteers underwent diffusion-weighted magnetic resonance imaging (MRI) of the neck at 3T with 11 dynamic acquisitions (9 b-values between 0 and 980 s/mm2 , 2:40 min each). After 5:20 minutes, a lemon-mint-drop was administered orally. Perfusion fraction (Fp ), pseudodiffusion (D*), tissue diffusion (Dt ) coefficients, and optimal b-value threshold were measured using a multistep variable b-value threshold fitting approach. Dynamic changes in the coefficients between three exemplary timepoints (baseline, after stimulation, after dissolution) were compared using a Mann-Whitney U-test with Bonferroni correction (P < 0.016 significance level). RESULTS: Mean values (95% confidence interval [CI]) for IVIM parameters at baseline were Fp : 0.11 (0.08-0.15), D*: 56.48 mm2 /s (39.71-98.27), Dt : 1.01 mm2 /s (0.84-1.06), b-value threshold: 30 s/mm2 (21.25-105). After stimulation: Fp 0.16 (0.15-0.24; P < 0.01), D* 93.83 mm2 /s (77.98-129.53, P = 0.25), Dt 0.93 mm2 /s (0.87-1.08, P = 0.94), b-value threshold 20 s/mm2 (13.75-26.25 s/mm2 , P = 0.10), reflecting the increase in tissue perfusion. After dissolution of the drop: Fp : 0.13 (0.11-0.18, P = 0.38), D*: 101.61 mm2 /s (90.68-144.55, P = 0.07), Dt : 0.91 mm2 /s (0.85-1.05, P = 0.64), b-value threshold: 15 s/mm2 (11.25-40, P = 0.38). CONCLUSION: The IVIM method allows for simultaneous quantification of changes in perfusion and diffusion effects after gustatory stimulation of the parotid gland. LEVEL OF EVIDENCE: 2 J. Magn. Reson. Imaging 2017;45:570-578.

Facial Nerve and Parotid Gland Anatomy.

This article provides an overview of important anatomic and functional anatomy associated with the parotid gland and facial nerve for the practicing otolaryngologist, head and neck surgeon, facial plastic surgeon, and plastic surgeon. The discussion includes the important anatomic relationships and physiology related to the parotid gland and salivary production. A comprehensive description of the path of facial nerve, its branches, and important anatomic landmarks also are provided.

Evaluation of Parotid Glands With Real-time Ultrasound Elastography in Children.

OBJECTIVES: The aim of this study was to determine the strain index for parotid glands in children by using ultrasound elastography. METHODS: In this prospective study, apparently healthy children were referred from the ear-nose-throat clinic to the radiology clinic for elastographic examinations. Conventional sonographic and elastographic examinations of the parotid glands were performed. A linear 5-12-MHz transducer was used to obtain the images. RESULTS: A total of 54 children were enrolled in this prospective study. The normal mean strain index value ± SD for the parotid glands was 1.24 ± 0.67 (range, 0.29-1.39) regardless of sex. The mean age of girls was 7.42 ± 2.94 years (range, 3-14 years), and the age of boys was 8.50 ± 3.46 years (range, 4-16 years). The strain index values for the parotid glands in boys was 1.25 ± 0.76, and in girls it was 1.22 ± 0.55. There was no statistically significant difference in the strain index values between girls and boys (P= .986). There was no correlation between the strain index and age (r = 0.026) or body mass index (r = 0.066). CONCLUSIONS: This study determined the mean strain index values for apparently healthy children. Such information can serve as a baseline from which pathologic parotid diseases can be diagnosed with ultrasound elastography in combination with other sonographic criteria.

Meta-Analysis of Salivary Flow Rates in Young and Older Adults.

OBJECTIVES: To determine whether salivary flow decreases as a function of aging. DESIGN: Meta-analysis. SETTING: Literature review. PARTICIPANTS: Individuals aged 18 and older reported to be free of major systemic disease. MEASUREMENTS: Relevant studies were identified through a literature search of several databases, from their inception to June 2013. Studies were included if saliva had been collected on at least one occasion in subjects aged 18 and older and if the data were presented in a manner that enabled comparisons of younger and older participants. Differences in salivary flow rates between age groups were calculated for each salivary source and condition and reported as standardized mean differences (SMDs), standard errors (SEs) and 95% confidence intervals (CIs). The results were pooled using a random effects model. A separate analysis examining medication use was also conducted. RESULTS: Forty-seven studies were included. Whole (SMD = 0.551, SE = 0.056, 95% CI = 0.423-0.678, P < .001) and submandibular and sublingual (SMSL) (SMD = 0.582, SE = 0.123, 95% CI = 0.341-0.823, P < .001) salivary flow rates were reduced significantly in older participants and in unstimulated and stimulated conditions. In contrast, parotid and minor gland salivary flow rates were not significantly reduced with increasing age. Additionally, unstimulated and stimulated SMSL, and unstimulated whole salivary flow rates were significantly lower in older adults, regardless of medication usage. CONCLUSION: The aging process is associated with reduced salivary flow in a salivary-gland-specific manner; this reduction in salivary flow cannot be explained on the basis of medications. These findings have important clinical implications for maintaining optimal oral health in older adults.