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Spit and phlegm
Readers will discover the science behind the gross studying why we need saliva to eat and phlegm to protect ourselves from bacteria and illness.
Book
The Essential Role of Tick Salivary Glands and Saliva in Tick Feeding and Pathogen Transmission
As long-term pool feeders, ticks have developed myriad strategies to remain discreetly but solidly attached to their hosts for the duration of their blood meal. The critical biological material that dampens host defenses and facilitates the flow of blood-thus assuring adequate feeding-is tick saliva. Saliva exhibits cytolytic, vasodilator, anticoagulant, anti-inflammatory, and immunosuppressive activity. This essential fluid is secreted by the salivary glands, which also mediate several other biological functions, including secretion of cement and hygroscopic components, as well as the watery component of blood as regards hard ticks. When salivary glands are invaded by tick-borne pathogens, pathogens may be transmitted via saliva, which is injected alternately with blood uptake during the tick bite. Both salivary glands and saliva thus play a key role in transmission of pathogenic microorganisms to vertebrate hosts. During their long co-evolution with ticks and vertebrate hosts, microorganisms have indeed developed various strategies to exploit tick salivary molecules to ensure both acquisition by ticks and transmission, local infection and systemic dissemination within the vertebrate host.
Journal Article
Value of Routine Dengue Diagnostic Tests in Urine and Saliva Specimens
Dengue laboratory diagnosis is essentially based on detection of the virus, its components or antibodies directed against the virus in blood samples. Blood, however, may be difficult to draw in some patients, especially in children, and sampling during outbreak investigations or epidemiological studies may face logistical challenges or limited compliance to invasive procedures from subjects. The aim of this study was to assess the possibility of using saliva and urine samples instead of blood for dengue diagnosis.
Serial plasma, urine and saliva samples were collected at several time-points between the day of admission to hospital until three months after the onset of fever in children with confirmed dengue disease. Quantitative RT-PCR, NS1 antigen capture and ELISA serology for anti-DENV antibody (IgG, IgM and IgA) detection were performed in parallel on the three body fluids. RT-PCR and NS1 tests demonstrated an overall sensitivity of 85.4%/63.4%, 41.6%/14.5% and 39%/28.3%, in plasma, urine and saliva specimens, respectively. When urine and saliva samples were collected at the same time-points and tested concurrently, the diagnostic sensitivity of RNA and NS1 detection assays was 69.1% and 34.4%, respectively. IgG/IgA detection assays had an overall sensitivity of 54.4%/37.4%, 38.5%/26.8% and 52.9%/28.6% in plasma, urine and saliva specimens, respectively. IgM were detected in 38.1% and 36% of the plasma and saliva samples but never in urine.
Although the performances of the different diagnostic methods were not as good in saliva and urine as in plasma specimens, the results obtained by qRT-PCR and by anti-DENV antibody ELISA could well justify the use of these two body fluids to detect dengue infection in situations when the collection of blood specimens is not possible.
Journal Article
Untargeted stimulated and unstimulated salivary metabolomics and saliva flow rate in children
Objective
The present study aimed to determine the salivary flow and metabolomic profile of stimulated and unstimulated saliva in children.
Materials and methods
Children who attended the Pediatric Dentistry Clinic of the State University of Rio de Janeiro -UERJ between 3 and 12 years of age were selected. Unstimulated and stimulated whole saliva, using mechanical stimulus, were collected. The samples were centrifuged at 12,000
g
, 4
o
C for 1 h. The
1
H- NMR spectra were acquired in 500 MHz equipment. The data were extracted into 0.03 ppm buckets in AMIX, and multivariate analysis (PLS-DA and O-PLS-DA) was performed in Metaboanalyst 2.0. For other analyses, such as salivary flow, the data was tabulated in the SPSS 20.0 statistical package, analyzed descriptively, and after applying the Wilcoxon test. The interval of confidence was set at 95%.
Results
The mean age was 7.5 (± 1.94), and 47.0% (
n
= 31) were female, 63.6% (
n
= 42). The median flow rate for stimulated saliva was 0.74 (IC 0.10–2.40) and was statistically higher (
p
< 0.001; Wilcoxon test) than unstimulated was 0.39 (IC 0.00–1.80). Children older than seven years old also presented a higher difference between unstimulated and stimulated saliva (
p
= 0.003; Mann-Whitney test). The PLS-DA and O-PLS-DA demonstrated a different profile in stimulated and unstimulated saliva. Acetate, glucose, propionate, and lysine were higher in the unstimulated whole saliva than in stimulated saliva. Isoleucine, N-acetyl sugar, hydroxybutyrate, glutamate, leucine, propionate, butyrate, valine, isoleucine, succinate, saturated fatty acid, and histidine were found in greater amounts in the saliva of patients with stimulated saliva.
Conclusion
The stimulated saliva presented a higher flow rate, and older children exhibited a higher flow rate resulting from it’s the stimulus. The mechanical stimulus increased the levels of the major metabolites.
Journal Article
Survey of Saliva Components and Virus Sensors for Prevention of COVID-19 and Infectious Diseases
The United States Centers for Disease Control and Prevention considers saliva contact the lead transmission mean of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes the coronavirus disease 2019 (COVID-19). Saliva droplets or aerosols expelled by sneezing, coughing, breathing, and talking may carry this virus. People in close distance may be exposed directly to these droplets or indirectly when touching the droplets that fall on surrounding surfaces and ending up contracting COVID-19 after touching the mucosa tissue of their faces. It is of great interest to quickly and effectively detect the presence of SARS-CoV-2 in an environment, but the existing methods only work in laboratory settings, to the best of our knowledge. However, it may be possible to detect the presence of saliva in the environment and proceed with prevention measures. However, detecting saliva itself has not been documented in the literature. On the other hand, many sensors that detect different organic components in saliva to monitor a person’s health and diagnose different diseases, ranging from diabetes to dental health, have been proposed and they may be used to detect the presence of saliva. This paper surveys sensors that detect organic and inorganic components of human saliva. Humidity sensors are also considered in the detection of saliva because a large portion of saliva is water. Moreover, sensors that detect infectious viruses are also included as they may also be embedded into saliva sensors for a confirmation of the presence of the virus. A classification of sensors by their working principles and the substances they detect is presented, including the sensors’ specifications, sample size, and sensitivity. Indications of which sensors are portable and suitable for field application are presented. This paper also discusses future research and challenges that must be resolved to realize practical saliva sensors. Such sensors may help minimize the spread of not only COVID-19 but also other infectious diseases.
Journal Article
Effects of Chlorhexidine mouthwash on the oral microbiome
Following a single blind, cross-over and non-randomized design we investigated the effect of 7-day use of chlorhexidine (CHX) mouthwash on the salivary microbiome as well as several saliva and plasma biomarkers in 36 healthy individuals. They rinsed their mouth (for 1 min) twice a day for seven days with a placebo mouthwash and then repeated this protocol with CHX mouthwash for a further seven days. Saliva and blood samples were taken at the end of each treatment to analyse the abundance and diversity of oral bacteria, and pH, lactate, glucose, nitrate and nitrite concentrations. CHX significantly increased the abundance of Firmicutes and Proteobacteria, and reduced the content of Bacteroidetes, TM7, SR1 and Fusobacteria. This shift was associated with a significant decrease in saliva pH and buffering capacity, accompanied by an increase in saliva lactate and glucose levels. Lower saliva and plasma nitrite concentrations were found after using CHX, followed by a trend of increased systolic blood pressure. Overall, this study demonstrates that mouthwash containing CHX is associated with a major shift in the salivary microbiome, leading to more acidic conditions and lower nitrite availability in healthy individuals.
Journal Article
Alleviation of dry mouth by saliva substitutes improved swallowing ability and clinical nutritional status of post-radiotherapy head and neck cancer patients: a randomized controlled trial
Purpose
The aim of this study is to investigate the effect of an edible saliva substitute, oral moisturizing jelly (OMJ), and a topical saliva gel (GC) on dry mouth, swallowing ability, and nutritional status in post-radiotherapy head and neck cancer patients.
Methods
Sixty-two post-radiation head and neck cancer patients with xerostomia completed a blinded randomized controlled trial. They were advised to swallow OMJ (
n
= 31) or apply GC orally (
n
= 31) for 2 months. Outcome measures were assessed at baseline, 1, and 2 months, including subjective and objective dry mouth (Challcombe) scores, subjective swallowing problem scores (EAT-10), water swallowing time, clinical nutritional status (PG-SGA), body weight, and dietary intake.
Results
After 1 and 2 months of interventions, subjective and objective dry mouth scores, subjective swallowing problem scores, swallowing times, and clinical nutritional status in both groups were significantly improved (
p
< 0.0001). Compared to GC, OMJ group had higher percent improvement in all outcome measures (
p
< 0.001) except swallowing time and clinical nutritional status. Interestingly, subjective dry mouth scores were significantly correlated with subjective swallowing problem scores (
r
= 0.5321,
p
< 0.0001).
Conclusions
Continuous uses of saliva substitutes (OMJ or GC) for at least a month improved signs and symptoms of dry mouth and enhanced swallowing ability. An edible saliva substitute was superior to a topical saliva gel for alleviating dry mouth and swallow problems. These lead to improved clinical nutritional status. Thus, palliation of dry mouth may be critical to support nutrition of post-radiotherapy head and neck cancer patients.
Clinical trial registry
Clinicaltrials.gov
NCT03035825
Journal Article
Molecular sabotage of plant defense by aphid saliva
Aphids, which constitute one of the most important groups of agricultural pests, ingest nutrients from sieve tubes, the photoassimilate transport conduits in plants. Aphids are able to successfully puncture sieve tubes with their piercing mouthparts (stylets) and ingest phloem sap without eliciting the sieve tubes' normal occlusion response to injury. Occlusion mechanisms are calcium-triggered and may be prevented by chemical constituents in aphid saliva injected into sieve tubes before and during feeding. We recorded aphid feeding behavior with the electrical penetration graph (EPG) technique and then experimentally induced sieve tube plugging. Initiation of sieve tube occlusion caused a change in aphid behavior from phloem sap ingestion to secretion of watery saliva. Direct proof of \"unplugging\" properties of aphid saliva was provided by the effect of aphid saliva on forisomes. Forisomes are proteinaceous inclusions in sieve tubes of legumes that show calcium-regulated changes in conformation between a contracted state (below calcium threshold) that does not occlude the sieve tubes and a dispersed state (above calcium threshold) that occludes the sieve tubes. We demonstrated in vitro that aphid saliva induces dispersed forisomes to revert back to the nonplugging contracted state. Labeling Western-blotted saliva proteins with ⁴⁵Ca²⁺ or ruthenium red inferred the presence of calcium-binding domains. These results demonstrate that aphid saliva has the ability to prevent sieve tube plugging by molecular interactions between salivary proteins and calcium. This provides aphids with access to a continuous flow of phloem sap and is a critical adaptation instrumental in the evolutionary success of aphids.
Journal Article
Saliva or Nasopharyngeal Swab Specimens for Detection of SARS-CoV-2
In this letter, the investigators report that saliva specimens and nasopharyngeal swab specimens had similar sensitivity in the detection of SARS-CoV-2 RNA in both symptomatic and asymptomatic persons.
Journal Article