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Abstract

Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes erosive changes and ankylosis of joints and may cause internal injuries. Osteoarthritis (OA) is a degenerative process of the articular cartilage. However, inflammatory mediators may play a pivotal role in the initiation and perpetuation of the OA process. It is necessary to continue to study possible factors that may promote the development of the disease. The goal of this study was to evaluate the frequency and activity stage of parvovirus B19 (B19V) and persistent human herpes virus (HHV)-6 and HHV-7 infection in RA and OA patients, and healthy persons, in relation to cytokine levels and presence or absence of viral infections. RA patients with active B19V infection had the highest levels of tumour necrosis factor alpha (TNF-α), which may contribute to the development of RA. In the case of OA, the TNF-α level was higher in patients with active persistent B19V infection, suggesting that B19V reactivation affects also OA. Interleukin (IL)-6, IL-10 and metalloproteinase (MMP)-9 levels were higher in RA patients with latent HHV-6/-7 infection in comparison with active HHV-6/-7 infection, whereas in OA patients levels of all studied cytokines were very variable, ranging from low to high but without significant differences. This suggests that also latent HHV-6 and -7 viral infections can promote development of RA.

Open access

Abstract

Let R be a principal ideal domain with quotient field K, and L = K(α), where α is a root of a monic irreducible polynomial F (x) ∈ R[x]. Let ℤL be the integral closure of R in L. In this paper, for every prime p of R, we give a new efficient version of Dedekind’s criterion in R, i.e., necessary and sufficient conditions on F (x) to have p not dividing the index [ℤL: R[α]], for every prime p of R. Some computational examples are given for R = ℤ.

Open access

Abstract

Immune activation in human immunodeficiency virus (HIV) infection is driven by microbial translocation and in HIV patients is one of the contributors to faster progression of liver disease along with increased cell apoptosis. The aim of the study was to compare microbial translocation and apoptosis markers in HIV monoinfected and HIV/hepatitis C virus (HCV) coinfected patients, depending on HIV immune status and antiretroviral treatment (ART). We analysed data for 78 HIV monoinfected and 105 HIV/HCV coinfected patients from the Rīga East University Hospital. Lipopolysaccharide (LPS), endotoxin core antibodies (EndoCAb), cytokeratin 18 (CK18) and cyto-chrome c (Cyt-c) levels were measured. No significant difference in LPS, EndoCAb, Cyt-c levels between HIV and HIV/HCV patients was found. The CK18 level was higher in the HIV/HCV group. Correlation between CD4+ cell count and EndoCAb antibodies was found in HCV positive patients. There was a significant effect of ART on markers for EndoCAb IgA and EndoCAb IgM antibodies in the HIV monoinfected group. Correlation between CD4+ cell count and EndoCAb antibodies and LPS was found in HIV/HCV patients on ART. Coinfection with HCV can lead to more pronounced response in EndoCAb antibody production and higher levels of cell apoptosis markers, despite similar LPS levels. ART has a positive effect on immune activation.

Open access

Abstract

The aim of this study was to assess the relationship between HLA Class II alleles in two groups of patients in Latvia: patients with cystic and alveolar echinococcosis. The study included 37 patients from the Rīga East Clinical University Hospital with echinococcosis (29 patients with cystic echinococcosis and eight patients with alveolar echinococcosis) and 100 healthy control persons without echinococcosis. HLA Class II allele genotyping was performed using Real-time polymerase chain reaction–sequence specific primer (RT-PCR-SSP). The odds ratios (OR), with 95% confidence intervals (95% CI), were calculated using statistical analysis performed with IBM SPSS Statistics for Windows, Version 22.0, to evaluate the risk of developing the disease in an individual having a particular HLA genotype. In the case of cystic echinococcosis a more severe course of a disease can be anticipated in the presence of HLA-DRB1 alleles *17:01 and *07:01, -DQB1 *03:02, and *03:01, -DQA1*04:01 and haplotypes HLA-DRB1*04:01/-DQB1*03:01/ -DQA1*03:01, HLADRB1*11:01/ -DQB1*03:01 /-DQA1*05:01. However, in the group with alveolar echinococcosis it was associated with the HLA-DRB1 alleles *17:01 and *07:01, -DQB1 *05:01 and haplotypes HLA- DRB1*17:01/-DQB1*02:01-2/-DQA1*01:01, HLA-DRB1*11:01/ -DQB1*03:01/-DQA1*01:03 and HLA-DRB1*11:01/-DQB1*03:01/-DQA1*03:01. HLADRB1*15:01/-DQÂ1*06:02-8/-DQA1*05:01 and HLA-DRB1*13:01/-DQB1*02:01-2/-DQA1*05:01 haplotypes were protective in all patient groups. The limitations of this exploratory study indicate that a broader study needs to be conducted for revealing specific risk and protective HLA Class II haplotypes for patients with cystic and alveolar echinococcosis in Latvia.

Open access

Abstract

Until now, the assessment of health care services provided by psychiatric institutions in Latvia has not been carried out and questionnaires to provide assessment from the patient’s perspective have not been adapted. For this study, a questionnaire that has been validated and successfully employed for several years in Norway was chosen to assess patients’ experience and in a psychiatric inpatient setting. The aim of the study was to determine patients’ satisfaction with the quality of mental health care services in Latvia in the subacute inpatient psychiatric ward in Rīga, adapting during this process the PIPEQ-OS (Psychiatric Inpatient Patient Experience Questionnaire) tool in Latvia. The pilot quantitative study was conducted from June 2016 till February 2017. In the study, an anonymous patient self-assessment questionnaire PIPEQ-OS containing 21 questions was used. During the adaptation process, the questionnaire was translated from English into Latvian and Russian and backwards. The quality and compliance of the translation was subsequently tested in cognitive interviews. During the study, 297 patients were discharged from the unit, and 231 of them completed the questionnaire. 12% of the completed questionnaires were not included in data processing due to being incorrectly filled in. Cognitive interviews with 20 patients were carried out; the average length of an interview was 15 minutes. Overall, the translation of the questionnaire proved to be relevant to the research theme. The subsequent factor analysis revealed three significant factors that reached the Cronbach’s alpha index of 0.7. Further studies using socio-demographic data and based on various inpatient units as well as the comparison of satisfaction indicators across different diagnostic groups are needed.

Open access

Abstract

Competitiveness as a factor of a company selling its services in the market is becoming more relevant in the healthcare sector. The number of institutions that offer their services to international patients is growing. Research shows that the development of medical tourism is country-specific. The main objective of this publication is to discover positive and negative factors for engagement in the provision of services to non-residents. The data was obtained from a cross-sectional study in which 86 managers of health care institutions in Latvia completed a questionnaire. A total of 80.2% of health care institutions had provided services to non-resident patients in the previous year while 19.8% did so regularly. Institutions mainly used websites to advertise their services. Only a small number of institutions employed a marketing specialist or had a strategy to attract non-resident patients. Heads of institutions pointed to a number of internal and external barriers in this connection, including lack of staff, low motivation, limited language skills, inadequate infrastructure, insufficient state-level support to promote the export of services, the social environment, and problems in the health system itself. The study revealed areas that need to be improved regarding future policies to attract non-resident patients and to increase global competitiveness.

Open access

Abstract

In this paper, we propose a new approximate method, namely fractional natural decomposition method (FNDM) in order to solve a certain class of nonlinear time-fractional wave-like equations with variable coefficients. The fractional natural decomposition method is a combined form of the natural transform method and the Adomian decomposition method. The nonlinear term can easily be handled with the help of Adomian polynomials which is considered to be a clear advantage of this technique over the decomposition method. Some examples are given to illustrate the applicability and the easiness of this approach.

Open access

Abstract

Let G be a group with identity e and let R be a G-graded ring. In this paper, we introduce and study the concept of gr-n-ideals of R. We obtain many results concerning gr-n-ideals. Some characterizations of gr-n-ideals and their homogeneous components are given.

Open access

Abstract

We study a family of harmonic univalent functions in the open unit disc defined by using post quantum calculus operators. We first obtained a coefficient characterization of these functions. Using this, coefficients estimates, distortion and covering theorems were also obtained. The extreme points of the family and a radius result were also obtained. The results obtained include several known results as special cases.

Open access

Abstract

T-310 is an important Cold War cipher. The cipher is extremely complex and it outputs extremely few bits from the internal state. A recent paper [Courtois, N. T.: Decryption oracle slide attacks on T-310, Cryptologia, 42 (2018), no. 3, 191–204] shows an example of a highly anomalous key such that T-310 can be broken by a slide attack with a decryption oracle. In this paper, we show that the same attacks are ALSO possible for regular keys which satisfy all the official KT1 requirements. Two other recent papers [Courtois, N. T.—Georgiou, M.—Scarlata, M.: Slide attacks and LC-weak keys in T-310, Cryptologia 43 (2019), no. 3, 175–189]; [Courtois, N. T.—Oprisanu, M. B.—Schmeh, K.: Linear cryptanalysis and block cipher design in East Germany in the 1970s, Cryptologia (published online), December 5, 2018] show that some of the KT1 keys are very weak w.r.t. Linear Cryptanalysis. In this paper, we show that a vast number of such weak keys exist and study the exact pre-conditions which make them weak. In addition we introduce a new third class of weak keys for RKDC (Related-Key Differential Cryptanalysis). We show that the original designers in the 1970s have ensured that these RKDC properties cannot happen for 4 rounds. We have discovered that these properties can happen for as few as 5 rounds for some keys, and for 10 to 16 rounds they become hard to avoid. The main reason why we study weak keys is to show that none of these properties occur by accident, rather that they are governed by precise pre-conditions which guarantee their existence, and countless other keys with the same properties exist. Eventually, this is how interesting attacks can be found.

Open access