ABSTRACT
BACKGROUND: Lung carcinoma is one of the most common malignancies worldwide. At present, unfortunately, there are no markers that would allow early identification of this tumor in the preclinical or early clinical stage. The use of sniffer dogs has been reported to show some promise in early diagnosis of this type of cancer Aim: This study aimed to evaluate the possibility of utilizing changes in the heart rate of sniffer dogs (which increases when finding a positive sample) in tumor detection. METHODS: This double-blinded pilot study included two sniffer dogs. A chest strap was fastened on the dog's chests for heart rate monitoring while they were examining samples and heart rate was recorded. Test parameters (sensitivity, specificity, positive and negative predictive values) were then calculated, evaluating performances based on (i) the dog's indications according to their training and (ii) the changes in their heart rates. RESULTS: Calculation according to the dog's indications revealed an overall sensitivity of 95.2% accompanied by a specificity of 81.8%, a PPV of 93.7%, and an NPV of 85.7%, respectively. These results were not significantly different from those evaluated by heart rate; heart rate monitoring was, however, burdened with a relatively high proportion of invalid experiments in which heart rate measurement failed. When the method of calculation was changed from rounds to individual samples, the test parameters further increased. CONCLUSIONS: This pilot study confirmed the hypothesis that heart rate increases in trained sniffer dogs when encountering samples from tumor-positive patients but remains unchanged when only negative samples are present. The reliability of results based on heart rate increase is similar to that obtained by a dog's indications and, if the limitation represented by technical issues is overcome, it could serve as a valuable verification method.
ABSTRACT
BACKGROUND: The noninvasive collection of saliva samples for DNA analyses is simple, and its potential for research and diagnostic purposes is great. However, DNA isolates from such samples are often of inferior quality to those from blood. AIM: The aim of this study was to investigate the robustness and sensitivity of the ddPCR instrument for genetic analyses from saliva samples of poor quality by comparing their results to those obtained using an established method from blood samples. METHODS: Blood and saliva were collected from 47 university students, which was followed by manual isolation of DNA and analysis on droplet digital PCR (ddPCR). Results of analyses were supplemented with values of fractional abundances. RESULTS: ddPCR proved to be highly suitable for analysis of even low-quality saliva samples (concentrations as low as 0.79 ng/µL), especially when augmented by fractional abundance data. This combination yielded 100% agreement with results obtained from blood samples. CONCLUSION: This study verified the applicability of ddPCR as a sensitive and robust method of genetic diagnostic testing even from low-quality saliva isolates. This makes it potentially suitable for a wide range of applications and facilitates the performance of large epidemiological studies, even if sampling or sample processing is suboptimal.
ABSTRACT
BACKGROUND: Thrombophilic mutations in genes for factor V Leiden and factor II prothrombin are among the most important risk factors for developing the thromboembolic disease (TED), along with the use of oral contraceptives (OCs) or smoking. AIM: This study aimed to investigate the occurrence of risk factors in young women using droplet digital PCR (ddPCR) and, based on the results of this investigation, to perform a cost-benefit analysis of ddPCR-based screening in young women starting to take OCs compared to the treatment costs of patients who develop preventable TED in the Czech Republic. METHODS: In this cross-sectional study, female university students filled in a questionnaire and provided a blood sample for DNA isolation and ddPCR analysis of both aforementioned genetic risk factors. The results, along with data from literature and web search, were used for cost-benefit analysis valid for the Czech Republic. RESULTS: Out of 148 participants, 30 (20%) were smokers and 49 (33%) took OCs. A mutation was confirmed in 6 women (4.1%) in the factor V gene and in 3 women (2%) in the factor II gene, respectively. A model calculation on a cohort of 50,000 women starting to use contraceptives in the Czech Republic every year showed that at maximum compliance, (i.e., non-use of OC and smoking cessation), screening could prevent 68 cases of TED over the course of the mean period of OC use (5.7 years). Economically, the costs of testing in this cohort (2.25 mil. USD) would be significantly lower than prevented treatment costs (16 mil. USD at maximum compliance); the cost-benefit break-even point would be at 14.1% compliance. CONCLUSION: The cost-benefit analysis based on our results indicates that screening for factor V Leiden and factor II prothrombin in young women before starting to use OCs would, in the conditions of the Czech Republic, likely be highly economically effective.
