A chemotherapeutic drug 6-thioguanine (2-amino-1,7-dihydro-6H-purine-6-thione, 6-TG) has been studied experimentally in the solid state by NMR-NQR double resonance and theoretically by the density functional theory. Fourteen resonance frequencies on (14)N have been detected and assigned to particular nitrogen sites in the 6-TG molecule. A valid assignment of NQR frequencies for 6-mercaptopurine (6-MP) has been proposed. The effects of molecular aggregations, related to intermolecular hydrogen bonding and stacking pi-pi interactions on the NQR parameters have been analyzed within the DFT and AIM (atoms in molecules) formalism for 6-TG and 6-mercaptopurine (6-MP). The so-called global reactivity descriptors have been calculated to compare the properties of molecules of 6-TG and 6-MP, to check the effect of -NH(2) group as well as to identify the differences in crystal packing.
A potential antileukemic and anticancer agent, 2-thiocytosine (2-TC), has been studied experimentally in the solid state by 1H-14N NMR-NQR double resonance (NQDR) and theoretically by the quantum theory of atoms in molecules (QTAIM)/density functional theory (DFT). Eighteen resonance frequencies on 14N were detected at 180 K and assigned to particular nitrogen sites (−NH2, –N=, and –NH–) in 2-thiocytosine. Factors such as the nonequivalence of molecules (connected to the duplication of sites) and possible prototropic tautomerism (capable of modifying the type of site due to proton transfer) were taken into account during frequency assignment. The result of replacing oxygen with sulfur, which leads to changes in the intermolecular interaction pattern and molecular aggregation, is discussed. This study demonstrates the advantages of combining NQDR and DFT to extract detailed information on the H-bonding properties of crystals with complex H-bonding networks. Solid-state properties were found to have a profound impact on the stabilities and reactivities of both compounds.FigureThe experimental 1H-14N NQDR spectrum of 2-thiocytosine obtained at T = 180 K by the solid effect technique (left) and 3d distribution of the electron density Laplacian calculated by DFT (right)
Abstrakt
Background
Diabetes and periodontitis belong to the group of civilizational diseases, which are not associated with any specific bacterial or viral infection but with the rapid development of civilization and technological advances that affect comfort and quality of life. Civilizational diseases occur in highly developed and developing societies. Glycosylated hemoglobin A1c (HbA1c) is one of the standard indicators for the assessment of metabolic compensation in diabetes that reflects the risk of disease complications. One of the significant complications of diabetes that manifests in the oral cavity is gingival and periodontal inflammation, which is directly related to increased insulin resistance and worsened diabetes compensation. Factors influencing inflammation are the patient’s age, directly linked with fine motor skills when it comes to cleaning teeth, and patients’ awareness related to cause-and-effect relationship between dental hygiene, gingival and periodontal inflammation, and HbA1c testing during routine check-ups.
Objectives
To compare the relationship between gingival inflammation and metabolic compensation (HbA1c levels), depending on the patient’s age.
Materials and methods
The study involved 100 patients (50 adolescents and 50 adults, 42 M; 58 F) with type 1 diabetes. The study group was divided according to sex and age into 19 male adolescent patients (10–18 years old; mean age 15.5) and 23 male adult patients (19–45 years old; mean age 27.1). The mean duration of diabetes was 7 years in the group of adolescents and 11 years in the group of adults. The HbA1c levels and gingival index (GI) were measured in all patients. The obtained results were statistically analyzed.
Results
By comparing the study groups, higher HbA1c values were reported in the group of adolescents. HbA1c has been shown to correlate with the GI in adolescents and adults. Despite poorer compensation for diabetes (higher HbA1c), GI values were similar in adolescents and adults.
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