In package inactivation of Bacillus atrophaeus spores using high voltage atmospheric cold plasma

Introduction: Hospital acquired infections are of a great concern, considering a large number of infections reported every year. Sterilization is an important step in healthcare industry that is attained by utilizing conventional sterilization approaches. It includes heat treatment, use of chemicals like ethylene oxide, hydrogen peroxide, and gamma radiation. These methods have drawbacks such as material properties of medical devices could be altered or damaged. Therefore, it is necessary to investigate cheap alternative approaches to achieve sterilization without generating toxic residues. Nonthermal atmospheric plasma is a fourth state of matter that consists of charged particles, positive and negative ions and number of reactive species. This plasma mixture has greater microbicidal effects on number of food products and wide range of surfaces. Novel nonthermal plasma technology has number of applications in food and medical industries. Methods: The objective of this study was to investigate the effect of plasma parameters on inactivation of resistant biological forms of Bacillus atrophaeus inside a sealed package. Bacillus atrophaeus spore strip (spore population 6.36 log10/strip) was placed in a petri dish, sealed in a polypropylene container, and was subjected to high voltage atmospheric cold plasma treatment (HVACP). HVACP system was operated at 70 kVRMS and at a frequency of 50 Hz. The two 15-cm diameter aluminum disk electrodes were separated by a rigid polypropylene container which served as a sample holder and as a dielectric barrier. The distance between the two electrodes was equal to the height of the container (22 mm). The top electrode served as a high voltage electrode and bottom electrode was grounded. The discharge was monitored using electrical probes and an Agilent InfiniVision 2000 X-Series Oscilloscope. Influence of different process parameters on spore inactivation including treatment time, mode of exposure (direct/indirect), and working gas types were mainly evaluated. Effect of relative humidity on HVACP inactivation efficacy was also assessed. The inactivation efficacy was determined using standard colony count method. To assess gas composition following HVACP exposure, optical absorption spectroscopy was used. Results: A strong effect of process parameters on inactivation was observed. Direct exposure to plasma was very effective for spore inactivation, achieving ≥6 log cycle reduction of spores in all gas types tested, in only 60 s of treatment time. However, a strong influence of gas type was noted on spore reductions where indirect mode of plasma exposure was utilized. The relative humidity also noted as a critical factor in bacterial spore inactivation by HVACP, where a major role of plasma generated species other than ozone was noted. Conclusion: Overall, a strong influence of process parameters on spore inactivation was noted. Effective in-package bacterial spore inactivation within 30‑60 s demonstrates the promising potential application of HVACP for sterilization of medical devices and heat sensitive materials

Acute Myeloblastic Leukemia and Myelodysplastic Syndrome: Azacitidine for Prophylactic and Preventive Purposes after Allogeneic Hematopoietic Stem Cell Transplantation

Aim. To evaluate the effectiveness of preventive and prophylactic post-transplantation therapy using azacitidine (5-AZA) in patients at high risk of post-transplantation relapse. Methods. 136 patients were included in the study performed by the pairwise comparison: 68 of them received 5-AZA after allo-HSCT and 68 patients were included in the historical control group. 5-AZA was prescribed for prophylactic or preventive purposes. The results were assessed according to the OS, RR, EFS, DUM, and relapse-free and GVHR-free survival. Results. 1-year OS was 76 % in the 5-AZA group (95% CI 60–84 %) and 44 % in the reference group (95% CI 33–55 %) (p = 0.001); 2-year OS was 63 % (95% CI 39–67 %) and 37 % (95% CI 26–48 %) (p = 0.007), respectively. The relapse rate (RR) in the 5-AZA group was 34 % (95% CI 22–46 %) during 1 year and 51 % (95% CI 38–64 %) in the reference group (p = 0.02). 1- and 2-year disease unrelated mortality (DUM) was similar: 5 % in the 5-AZA group (95% CI 0.1–14.0 %) and 25 % (95% CI 13–37 %) in the reference group (p = 0.005). 1-year EFS was 76 % in the 5-AZA group (95% CI 61–85 %) and 44 % in the reference group (95% CI 33–55 %) (p = 0.001); 2-year EFS was 63 % (95% CI 39–67 %) and 37 % (95% CI 26–48 %) (p = 0.01), respectively. 1-year relapse-free and GVHR-free survival was 55 % in the 5-AZA group (95% CI 41–69 %) and 28 % in the reference group (95% CI 17–39 %) (p = 0.001); 2-year relapse-free and GVHR-free survival was 47 % (95% CI 32–62 %) and 27 % (95% CI 17–37 %) (p = 0.002), respectively. Conclusion. The use of 5-AZA for prophylactic and preventive purposes after allo-HSCT does not increase the risk of GVHR and DUM, does not suppress the GVL effect and can be used in combination with the donor lymphocyte infusion (DLI). The therapy with 5-AZA is safe during the early period after allo-HSCT. The drug does not suppress the GVL effect and can be used in high risk patients to prevent early post-transplantation relapse. The use of 5-AZA in combination with DLI does not increase the incidence of severe GVHR

Efficacy of Chemotherapy in Acute Leukemia Patients Resistant to Previous Standard Treatment According to the Series Measurement of WT1 Gene Expression

Aim. To estimate the efficacy of chemotherapy in acute leukemia patients resistant to previous standard treatment according to the series measurement of WT1 expression. Materials & Methods. The series measurement of WT1 expression formed the basis of the efficacy estimation of induction chemotherapy in 31 patients (15 men and 16 women aged from 3 months to 68 years; the median age was 28 years) with prognostically unfavourable variants of acute myeloid (AML) and lymphoblastic leukemia (ALL) (23 AML and 8 ALL patients). The WT1 gene expression was measured at baseline and 2–3 weeks after the treatment by the quantitative real-time PCR. The threshold level for detection was 250 copies of WT1/104 copies of ABL. The cytogenetic profile of leukemia cells was assessed by standard cytogenetics and FISH. Results. The baseline expression level of WT1 varied from 305 to 58,569 copies/104 copies of ABL. The expected reduction of WT1 expression after the first induction chemotherapy treatment was reported in 22/23 (96 %) AML patients and in 6/8 (75 %) ALL patients. According to our results WT1 expression reached the threshold in 13/31 (42 %) patients, including 9 AML patients and 4 ALL patients. After 11/31 (35 %) patients received the second course of treatment, WT1 expression level became normal in 8 cases (5 ALL and 3 AML patients). Despite high dose chemotherapy, HSCT and such agents as blinatumomab and gemtuzumab, an unfavourable outcome was observed in 18/31 (58 %) patients including 6 patients with complex karyotype (CK+) and 2 patients with monosomal karyotype (MK+). Once the MK+ and CK+ combination was observed, in another case the MK+ was combined with the prognostically unfavourable inv(3)(q21q26) inversion. Conclusion. Our results show that the molecular monitoring should be included as part of treatment of the prognostically unfavourable acute leukemia. The WT1 gene was shown to be the most appropriate marker. WT1 expression was shown to correlate with the common fusion genes allowing to estimate the blast cell count at the molecular level

Localization of the spectral expansions associated with the partial differential operators

In this paper we discuss precise conditions of the summability and localization of the spectral expansions associated with various partial differential operators. In this we study the problems in the spaces of both smooth functions and singular distributions. We study spectral expansions of the distributions with the compact support and classify the distributions with the Sobolev spaces. All theorems are formulated in terms of the smoothness and degree of the regularizations