In this article, the use of an SPME technique is reported for the first time for direct measurement of free drug concentration in solid tissue. In our investigations, we considered doxorubicin (DOX) spiked in homogenized tissue matrix at transient and equilibrium extraction conditions, with subsequent assessment of obtained experimental results by an in silico approach using mathematical models developed in COMSOL Multyphysics. In silico studies were performed on the basis of transported diluted species (tds) and reaction engineering (re) modules from COMSOL Multiphysics, using the same conditions as those used to attain experimental results. To determine the apparent binding affinity of DOX to the tissue matrix which contains multiple binding species, the experimentally determined binding affinity of DOX with human serum albumin (HSA) was considered to simplify the mathematical calculations. Here, the value of the binding affinity was considered for a single binding site and adjusted by fitting the experimental results with the mathematical model. Bovine lung tissue homogenate was selected as a surrogate matrix, and a biocompatible C-8 commercial SPME fiber was used for extraction of DOX. In total, four mathematical models were herein developed to describe the mass transfer kinetics of solid coatings: in agar gel at static conditions, in PBS solution with agitated conditions, extraction in PBS solution in the presence of an HSA binding matrix, and static extraction in homogenized lung tissue. For all conditions, simulated results were in good agreement with experimental results. The developed mathematical model allows for measurements of free drug concentrations inside the tissue matrix and facilitates calculations of local depletion of DOX by a solid SPME coating. Results of the investigations indicate that local depletion of the free form of DOX, even at the kinetic stage, is negligible for tissue extraction, as the release of the heavily bound analyte (over 99% binding to tissue matrix) is very rapid, thus easily compensating for the loss of the drug to the SPME coating. This indicates that the dissociation rate constant of DOX from lung tissue components is very rapid; therefore, the mass transfer of drug to the fiber coating via free from is very efficient. Our results also indicate that thin coating SPME fibers provide a good way to measure drug distribution after dosing, as extractions via thin coating SPME fibers do not affect the free concentration of the drug, which is responsible for drug distribution in tissue.

Objectives This study aims to investigate the low-resolution human leukocyte antigen (HLA)-B locus polymorphisms between unrelated healthy individuals and patients with diagnosis of seronegative spondyloarthropathies and determine risky and protective allelic groups and genotypes. Patients and methods The study included 104 healthy control individuals (52 males, 52 females; median age 43 years; range 2 to 76 years) and 96 patients (43 males, 53 females; median age 28.5 years; range 2 to 67 years) diagnosed with: ankylosing spondylitis (AS) (n=19), reactive arthritis (n=19), psoriatic arthritis (n=28) and undifferentiated spondyloarthropathies (n=30). Genomic deoxyribonucleic acid was extracted from peripheral blood to detect allelic groups of HLA class I and II. Single-specific-primer polymerase chain reaction was used for HLA genotyping and visualization of products after their separation on 1.5% agarose gel for horizontal gel electrophoresis. Results Significantly increased frequency was found for HLA-A*02 and HLA-B*27 allelic variants in all groups of patients. The increased frequency of the HLA-B*35 allelic group in the control group represents the protective gene variant for the occurrence of AS. The predisposing genotype (HLA-B*27/B*44 and B*27/B*51) for the onset of disease was only found in AS patients. Conclusion This study shows the strong association of HLA-B*27 antigen with spondyloarthropathies, which is considered a risk variant of the gene for the onset of disease. Protective and risky allelic variants and genotypes are rare and their detection as well as increased frequency are possible if larger numbers of patients are involved.

Purpose: The study aimed to determine the impact of communication disorders on discrimination against people who are deaf in the workplace, as well as to find the differences in study participants’ opinions. Method: The study sample consisted of 171 respondents from different industries in Bosnia-Herzegovina- 57 workers who were deaf, 57 workers who could hear, and 57 managers. Both quantitative and qualitative approaches were used in the survey. The opinions of the respondents were elicited through a questionnaire which consisted of 15 statements. The interviews of workers and managers focussed on the presence of discrimination against deaf workers in the workplace. Responses of respondents were converted to quantified values using analysis of discrimination group. The significance of statistical differences among the samples tested is defined at 0.01 level of significance using F-Test. Results: Discriminant analysis tested the null hypothesis that respondents’ answers do not differ regarding discrimination against deaf workers in the workplace. However differences were found between the groups that felt deaf workers did not have equal position at work in comparison to their hearing co-workers. Participants mentioned a number of barriers in workplaces. Workers were of the opinion that there was significant discrimination in the workplace (p>0.01) between groups of participants. Conclusion: There are statistically significant differences in the opinions of respondents regarding statements that workers who are deaf cannot hold positions equal to their co-workers who have regular hearing.