NMR Techniques in Metabolomic Studies: A Quick Overview on Examples of Utilization.

Metabolomics is a rapidly developing branch of science that concentrates on identifying biologically active molecules with potential biomarker properties. To define the best biomarkers for diseases, metabolomics uses both models (in vitro, animals) and human, as well as, various techniques such as mass spectroscopy, gas chromatography, liquid chromatography, infrared and UV-VIS spectroscopy and nuclear magnetic resonance. The last one takes advantage of the magnetic properties of certain nuclei, such as 1H, 13C, 31P, 19F, especially their ability to absorb and emit energy, what is crucial for analyzing samples. Among many spectroscopic NMR techniques not only one-dimensional (1D) techniques are known, but for many years two-dimensional (2D, for example, COSY, DOSY, JRES, HETCORE, HMQS), three-dimensional (3D, DART-MS, HRMAS, HSQC, HMBC) and solid-state NMR have been used. In this paper, authors taking apart fundamental division of nuclear magnetic resonance techniques intend to shown their wide application in metabolomic studies, especially in identifying biomarkers.

The application of positron emission tomography (PET/CT) in diagnosis of breast cancer. Part II. Diagnosis after treatment initiation, future perspectives.

Similarly to the applications described in the first part of this publication, positron emission tomography with computed tomography (PET/CT) is also gaining importance in monitoring a tumour's response to therapy and diagnosing breast cancer recurrences. This is additionally caused by the fact that many new techniques (dual-time point imaging, positron emission tomography with magnetic resonance PET/MR, PET/CT mammography) and radiotracers (16α-18F-fluoro-17ß-estradiol, 18F-fluorothymidine) are under investigation. The highest sensitivity and specificity when monitoring response to treatment is achieved when the PET/CT scan is made after one or two chemotherapy courses. Response to anti-hormonal treatment can also be monitored, also when new radiotracers, such as FES, are used. When monitoring breast cancer recurrences during follow-up, PET/CT has higher sensitivity than conventional imaging modalities, making it possible to monitor the whole body simultaneously. New techniques and radiotracers enhance the sensitivity and specificity of PET and this is why, despite relatively high costs, it might become more widespread in monitoring response to treatment and breast cancer recurrences.

The usefulness of fluorine-18 fluorodeoxyglucose PET in the detection of recurrence in patients with differentiated thyroid cancer with elevated thyroglobulin and negative radioiodine whole-body scan.

INTRODUCTION: PET/computed tomography (CT) using fluorine-18 fluorodeoxyglucose (F-FDG) has been used in the diagnosis of recurrence and metastases of differentiated thyroid cancer (DTC) in cases of negative whole-body scan (WBS) despite elevated concentrations of stimulated thyroglobulin (Tg). AIM: To assess the utility of PET/CT in the detection of recurrence among patients with DTC with increased Tg levels and negative results of WBS. MATERIALS AND METHODS: PET/CT results were retrospectively analyzed in patients with DTC with increased Tg and negative results of WBS as well as negative cervical ultrasonography and chest radiography. PET-CT was performed 1-2 weeks after recent diagnostics under conditions of endogenous or exogenous thyroid-stimulating hormone stimulation. PET/CT was performed using a Discovery ST scanner 1 h after an intravenously F-FDG injection (activity 4-5 MBq/kg). To determine the cutoff value of Tg, receiver operating characteristic curves were analyzed. RESULTS: Sixty-nine patients with DTC (48 women, 21 men) aged 22-83 years (mean 50.9±17.5 years) were qualified. In 44 patients (63.8%), PET/CT indicated lesions of DTC. Thirty (43.5%) patients had F-FDG positive findings. In the remaining 14 patients (20.3%), lesions were found in CT only. Patients with a positive PET/CT scan had significantly higher Tg values than patients with a negative PET/CT (mean 143.8 vs. 26.5 ng/ml, P=0.03). The cutoff value of Tg concentration measured with the receiver operating characteristic analysis was 32.9 ng/ml. CONCLUSION: PET/CT is a useful tool in the detection of recurrence among thyroid cancer patients in cases of conflicting results of standard procedures, particularly for those with high Tg levels and negative WBS. The probability of obtaining a positive PET-CT result increases with the level of Tg.

Application of positron emission tomography (PET/CT) in diagnosis of breast cancer. Part I. Diagnosis of breast cancer prior to treatment.

Positron emission tomography with computed tomography (PET/CT) is gaining popularity as a method for overall staging assessment of breast cancer. Currently, it is not a part of the routine workup before the beginning of treatment, because of insufficient sensitivity for the detection of small tumors (due to its limited spatial resolution), the heterogeneity of radiotracer uptake by the primary tumor, and unsatisfactory sensitivity in detection of lymph node metastases (particularly when they are small). Nevertheless, it should be considered when there is a high risk of metastases, because then initial PET/CT examination allows for accurate staging and may change the treatment algorithm in up to almost 50% of stage III patients, due to detection of distant and lymph node metastases throughout the whole body. Despite the discussed limitations of PET/CT, there is ongoing research concerning the recommendations for the examination prior to treatment. For a particular group of patients with high risk of metastases, PET/CT may be expected to become a part of the routine workup as the most appropriate staging method.

Effect of interferon λ3 gene polymorphisms, rs8099917 and rs12979860, on response to hepatitis B virus vaccination and hepatitis B or C virus infections among hemodialysis patients.

INTRODUCTION: The higher prevalence and risk of hepatitis B virus (HBV) or hepatitis C virus (HCV) infections are still observed in hemodialysis (HD) patients compared with healthy people. Interferons (IFNs) are known for their involvement in immune response. The addition of IFN-λ3 to immunization in animal models was shown to increase the immune response of T helper-1 cells. OBJECTIVES: We studied whether polymorphisms of the IFN-λ3 gene (IFNL3) might be associated with the development of antibodies to HBV surface antigen [anti-HBs] in response to the HBV vaccination or HBV infection as well as spontaneous resolution of HCV infection in HD patients. PATIENTS AND METHODS: The HD group consisted of 806 individuals without a history of HBV or HCV infection (of whom 672 developed anti-HBs in response to the HBV vaccination), 241 HBV-infected patients (of whom 186 developed anti-HBs), and 63 HCV-infected patients (including 39 HCV RNA-positive subjects). All patients were genotyped for IFNL3 rs8099917 and rs12979860 polymorphisms using a high-resolution melting curve analysis. RESULTS: The comparison of responders and nonresponders to HBV vaccination revealed no significant differences in the IFNL3 genotype distribution. In HBV-infected patients, the differences in the distribution of IFNL3 variants between anti-HBs-negative and anti-HBs-positive patients were also nonsignificant. Spontaneous HCV clearance was significantly less common in the carriers of the rs8099917 allele G or rs12979860 allele T, while the CT rs12979860_rs8099917 haplotype was more frequent (P = 0.02) in patients showing spontaneous HCV clearance. CONCLUSIONS: In HD patients, the IFNL3 polymorphisms do not affect anti-HBs development in response to HBV infection or vaccination, but might be involved in the resolution of HCV infection.

Investigations on Synperiplanar and Antiperiplanar Isomers of Losartan: Theoretical and Experimental NMR Studies.

Losartan inhibits the renin-angiotensin-aldosterone system by blocking the angiotensin II receptor. It is commonly used in cardiovascular diseases, such as hypertension. Several publications applied the ab initio and density functional theory methods to investigate the molecule of losartan. Only in one of them were the nuclear magnetic resonance spectra calculations carried out, and their results were correlated with the experimental values. The authors focused their attention on calculations of the anion form of losartan, taking into consideration both its synperiplanar and antiperiplanar configurations. Coefficients of determination and mean absolute deviation parameters were calculated for the experimental and calculated chemical shifts for every used basis set. They showed a noticeably stronger correlation for the anti-isomers than for the syn-isomers. Moreover, the solvation model increased the value of this parameter. The results of calculations confirmed that an anti-conformation of the analyte seems to be the preferred one, and such an orientation might be most potent within the receptor cavity, which is in agreement with the results of previous studies.

On the interactions of leflunomide and teriflunomide within receptor cavity--NMR studies and energy calculations.

Leflunomide is a disease-modifying antirheumatic drug with antiinflammatory and immunosuppressive activity used for the treatment of psoriatic and rheumatoid arthritis. It undergoes rapid metabolization to teriflunomide, a metabolite that is responsible for the biological activity of leflunomide. Continuing our investigations on the interactions of biologically important azahetarenes with the environment, we focused on leflunomide and its active metabolite, teriflunomide, considering the interactions teriflunomide-amino acid within the target protein (dihydroorotate dehydrogenase) using density functional theory, as well as ONIOM techniques. The results of theoretical studies have shown that the interactions of teriflunomide with tyrosine and arginine involve principally the amide fragment of teriflunomide. The presence of the internal hydrogen bond between (Z)-teriflunomide carbonyl oxygen and enolic hydroxyl decreases the interaction strength between teriflunomide and tyrosine or arginine. Even the E isomer of teriflunomide would usually provide a stronger interaction teriflunomide-amino acid than the Z isomer with the internal hydrogen bond.

Single nucleotide polymorphisms of vitamin D binding protein, vitamin D receptor and retinoid X receptor alpha genes and response to hepatitis B vaccination in renal replacement therapy patients.

AIM: Vitamin D (VD) was recently associated with response to hepatitis B vaccination in chronic kidney disease. We investigated whether polymorphisms in VD binding protein (GC), VD receptor (VDR) and retinoid X receptor α (RXRA) genes were associated with response to hepatitis B vaccination in renal replacement therapy (RRT) patients. METHOD: The study was carried out on 692 responders and 223 non-responders. RESULTS: After adjustment for gender, age at the RRT onset, RRT vintage, chronic glomerulonephritis as a cause of renal failure and mean serum parathyroid hormone level, VDR rs1544410 polymorphism was the only one significantly associated with response to hepatitis B vaccination: homozygotes AA (adjusted OR 1.50, 95% CI: 1.17-1.94, p = 0.002) had higher risk to be non-responders than GG homozygotes. DISCUSSION: The VDR rs1544410 AA genotype may play a negative role (but not as an independent factor) in determining response to hepatitis B vaccination in RRT patients.