Drug testing in oral fluid

Over the last decade there have been considerable developments in the use of oral fluid (saliva) for drug testing. Oral fluid can provide a quick and non-invasive specimen for drug testing. However, its collection may be thwarted by lack of available fluid due to a range of physiological factors, including drug use itself. Food and techniques designed to stimulate production of oral fluid can also affect the concentration of drugs. Current applications are mainly focused on drugs of abuse testing in employees at workplaces where drug use has safety implications, in drivers of vehicles at the roadside and in other situations where drug impairment is suspected. Testing has included alcohol (ethanol) and a range of clinical tests eg antibodies to HIV, therapeutic drugs and steroids. Its main application has been for testing for drugs of abuse such as the amphetamines, cocaine and metabolites, opioids such as morphine, methadone and heroin, and for cannabis. Oral fluid concentrations of basic drugs such as the amphetamines, cocaine and some opioids are similar or higher than those in plasma. Tetrahydrocannabinol (THC), the major species present from cannabis use, displays similar concentrations in oral fluid compared to blood in the elimination phase. However, there is significant local absorption of the drug in the oral cavity which increases the concentrations for a period after use of drug. Depot effects occur for other drugs introduced into the body that allow local absorption, such as smoking of tobacco (nicotine), cocaine, amphetamines, or use of sub-lingual buprenorphine. Screening techniques are usually an adaptation of those used in other specimens, with an emphasis on the parent drug since this is usually the dominant species present in oral fluid. Confirmatory techniques are largely based on mass spectrometry (MS) with an emphasis on Liquid Chromatography-Mass Spectrometry (LC-MS), due to low sample volumes and the low detection limits required. Drug testing outside laboratory environments has become widespread and provides presumptive results within minutes of collection of specimens. This review focuses on the developments, particularly over the last 10 years, and outlines the roles and applications of testing for drugs in oral fluid, describes the difficulties associated with this form of testing and illustrates applications of oral fluid testing for specific drugs.     

Inhibitory effect of oral Lactobacillus against oral pathogens

Aims: To determine the inhibitory effect of oral Lactobacillus against putative oral pathogens. Methods and Results: Total 357 strains comprising 10 species of oral Lactobacillus, Lactobacillus fermentum (195), Lactobacillus salivarius (53), Lactobacillus casei (20), Lactobacillus gasseri (18), Lactobacillus rhamnosus (14), Lactobacillus paracasei (12), Lactobacillus mucosae (12), Lactobacillus oris (12), Lactobacillus plantarum (11) and Lactobacillus vaginalis (10) were used as producer strains. Inhibitory effect against a panel of indicators, periodontitis‐ and caries‐related pathogens, was assessed. Most oral Lactobacillus was able to inhibit the growth of both periodontitis‐ and caries‐related pathogens. The strongest inhibitory activity was associated with Lact. paracasei, Lact. plantarum, Lact. rhamnosus, Lact. casei and Lact. salivarius. Lactobacillus SD1–SD6, representing the six species with the strong inhibitory effect, inhibited growth of Streptococcus mutans ATCC 25175 in the biofilm model. Also, it was demonstrated that growth of Strep. mutans was inhibited in a mixture with Lact. paracasei SD1. The inhibition was enhanced in acidic condition and 5% glucose. Conclusions: The results have shown that oral Lactobacillus SD1–SD6 showed a strong inhibitory effect against Strep. mutans and Streptococcus sobrinus, as well as, Gram‐negative periodontal pathogens Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. Significance and Impact of the Study: The results indicated that Lactobacillus may be of benefit as probiotics for the prevention of oral diseases.     

An oral hygiene protocol improves oral health for patients in inpatient stroke rehabilitation

The objective

To determine whether a simple oral hygiene protocol improves the oral health of inpatients in stroke rehabilitation.

The background data discussing the present status of the field

Poor oral health can lead to serious complications, such as pneumonia. The comorbidities associated with stroke, such as dysphagia, hemiparesis and cognitive impairment, can further impede independent oral care. International stroke guidelines recommend routine oral care but stop short of detailing specific regimes.

Materials and methods

The oral health assessment tool (OHAT) was conducted by speech‐language pathologists with 100 patients with and without dysphagia in three metropolitan inpatient stroke rehabilitation facilities. A simple nurse‐led oral hygiene regime was then implemented with all participants, which included twice daily tooth brushing and mouth rinsing after lunch, and oral health was measured again one week later.

Results

Initially, dysphagia was negatively associated with OHAT scores, and independence for oral hygiene was positively associated with oral health. After one week of a simple oral hygiene regime, the OHAT scores available for 89 participants indicated an improvement on average for all participants. In particular, 59% of participants with dysphagia had an improvement of 1 or more points. None of the participants developed pneumonia.

Conclusion

A simple, inexpensive oral hygiene regime resulted in positive outcomes for patients with and without dysphagia in inpatient stroke rehabilitation settings. Oral health assessments and oral hygiene regimes that are simple to implement by the interdisciplinary team can be incorporated into standard stroke care with positive effect.     

Measurement of warfarin in the oral fluid of patients undergoing anticoagulant oral therapy

Background

Patients on warfarin therapy undergo invasive and expensive checks for the coagulability of their blood. No information on coagulation levels is currently available between two controls.

Methodology

A method was developed to determine warfarin in oral fluid by HPLC and fluorimetric detection. The chromatographic separation was performed at room temperature on a C-18 reversed-phase column, 65% PBS and 35% methanol mobile phase, flow rate 0.7 mL/min, injection volume 25 µL, excitation wavelength 310 nm, emission wavelength 400 nm.

Findings

The method was free from interference and matrix effect, linear in the range 0.2–100 ng/mL, with a detection limit of 0.2 ng/mL. Its coefficient of variation was <3% for intra-day measurements and <5% for inter-day measurements. The average concentration of warfarin in the oral fluid of 50 patients was 2.5±1.6 ng/mL (range 0.8–7.6 ng/mL). Dosage was not correlated to INR (r = −0.03, p = 0.85) but positively correlated to warfarin concentration in the oral fluid (r = 0.39, p = 0.006). The correlation between warfarin concentration and pH in the oral fluid (r = 0.37, p = 0.009) confirmed the importance of pH in regulating the drug transfer from blood. A correlation between warfarin concentration in the oral fluid and INR was only found in samples with pH values ≥7.2 (r = 0.84, p = 0.004).

Conclusions

Warfarin diffuses from blood to oral fluid. The method allows to measure its concentration in this matrix and to analyze correlations with INR and other parameters.     

Evaluation of salivary endothelin-1 levels in oral squamous cell carcinoma and oral leukoplakia

Oral squamous cell carcinoma (OSCC) is the most frequent malignant neoplasia of the oral cavity, which largely compromises the patient's life quality. Therefore, the identification of biomarkers for this kind of cancer is essential to provide a better diagnosis and prognosis for patients. Endothelin-1 is a peptide produced mainly by endothelial cells, and might be found in several body fluids, such as saliva, milk, urine, cerebrospinal fluid and plasma. It has been demonstrated that expression of this peptide is increased in a great number of neoplasias, including oral carcinoma. The identification of salivary biomarkers would be a useful tool for scanning and monitoring patients with risk of developing OSCC, as well to early detect recurrence, or the formation of a new primary tumor. In the present study, we have analyzed the levels of endothelin-1 in saliva obtained from patients with OSCC or oral leukoplakia, in comparison to healthy control patients. This study also evaluated the salivary ET-1 levels in patients with complete remission of OSCC. The results revealed no statistical difference in salivary endothelin-1 levels, neither in OSCC nor in oral leukoplakia, even when conditions such as elderly, sex and hypertension were taken into consideration. Although, ET-1 might display an important role in OSCC, its levels in saliva do not seem to be a good marker of neoplasias grade or malignant transformation.     

Defective oral tolerance promotes nephritogenesis in experimental IgA nephropathy induced by oral immunization.

Oral tolerance, an important feature of the mucosal immune system, appears to protect against immune-mediated disease by blunting production of systemic IgG and IgM antibody directed toward immunogens chronically present at mucosal surfaces. In this study, we explored the role of oral tolerance and mucosal immunoregulation in an experimental model of IgA nephropathy (IgAN), an important form of nephritis in humans. Cyclophosphamide and estradiol were used to inhibit the expression of oral tolerance, which otherwise develops after chronic oral presentation of Ag. BALB/c mice given drinking water containing 0.1% bovine gamma globulin (BGG) continuously for 14 wk were randomly assigned to groups given either 2 mg of cyclophosphamide i.p., 2 mg of estradiol s.c. or both drugs. Groups of control mice received neither BGG nor drugs. In three separate experiments, a low percentage of saline-treated orally immunized mice had microscopic hematuria (0 to 20%), as did nonimmunized controls (0 to 20%). However, 58 to 83% of mice given estradiol and/or cyclophosphamide at appropriate times developed significant hematuria. If drugs were given at suboptimal times, only 25 to 56% of mice developed hematuria. Drug-treated immunized mice also had more serum IgG and IgM anti-BGG antibodies than control and saline groups. Immunofluorescence showed significantly more glomerular deposits of IgG, IgM, and C3 in drug-treated immunized mice compared to saline-treated immunized and normal untreated control mice. Hematuria and glomerular deposits of IgG, IgM, and C3 paralleled serum IgG and IgM antibody. All immunized mice showed significant mesangial IgA and BGG deposits and there were no differences in such deposits between saline- and drug-treated immunized mice. We suggest that blunting of oral tolerance with promotion of systemic IgG and IgM antibody production leads to nephritis in chronically orally immunized mice and that glomerular immune complexes containing IgG and/or IgM promote complement deposition and hematuria in IgAN. Analogous defects in oral (or more generally mucosal) tolerance could play a role in the genesis of symptomatic human IgAN.     

Roles of FGFR in oral carcinogenesis

Fibroblast growth factor receptors (FGFRs) play essential roles in organ development during the embryonic period, and regulate tissue repair in adults. Accumulating evidence suggests that alterations in FGFR signalling are involved in diverse types of cancer. In this review, we focus on aberrant regulation of FGFRs in pathogenesis of oral squamous cell carcinoma (OSCC), including altered expression and subcellular location, aberrant isoform splicing and mutations. We also provide an overview of oncogenic roles of each FGFR and its downstream signalling pathways in regulating OSCC cell proliferation and metastasis. Finally, we discuss potential application of FGFRs as anti‐cancer targets in the preclinical environment and in clinical practice.     

Extracellular DNA in oral microbial biofilms

The extracellular matrix of microbial biofilms is critical for surface adhesion and nutrient homeostasis. Evidence is accumulating that extracellular DNA plays a number of important roles in biofilm integrity and formation on hard and soft tissues in the oral cavity. Here, we summarise recent developments in the field and consider the potential of targeting DNA for oral biofilm control.     

基于微流控的生物被膜研究进展及口腔微生态系统应用展望

口腔是人体最重要的微生物储藏库之一,这些微生物通常以生物被膜的形式稳定地黏附于口腔内粘膜及牙齿表面,在病理条件下则可以深入髓腔及牙槽骨内,成为龋病、根尖周炎、牙周病等常见口腔疾病的主要病因,甚至与许多全身性疾病密切相关.在人类口腔微生态系统中,微生物种类繁多,生物被膜的构成及相互作用关系复杂,目前对其认识还十分有限;此...