Volume 76 (2022): Issue 2 (April 2022)

The convergence between a statistical mechanics and biological approach in elucidating some basic features of cell differentiation opens new avenues of research in gene expression regulation and holds some promises in terms of a re-differentiation approach to a cancer cure. The message emerging from two recent papers by the authors of the present communication follows very simple basic lines. The time-honored concept of homeostasis, at the very basis of physiology, is in action even at the microscopic level of gene expression regulation, where a continuous (relatively small) oscillation of gene expression is mandatory for keeping alive the substantial stability of the gene expression profile typical of a given cell type. This mechanism of stability, when oscillation exceeds a certain threshold, is responsible for the spreading of a large-scale perturbation invading the entire genome and eventually giving rise to cell fate change. The material basis of this model was discovered in the onset of a global reorganisation of chromatin driven by fusion-splitting dynamics of pericentromeric associated domains that, by selective folding/unfolding of chromatin, allows for a global scale re-arrangement of genome expression.

Treatment of advanced and metastatic prostate carcinoma (PCa) is still challenging and changing in the era of personalised medicine. Combination therapies with docetaxel and new anti-hormonal substances lead to improved OS (overall survival) in a broad group of patients with metastatic hormone sensitive prostate carcinoma (mHSPCa). Addition of docetaxel or an androgen receptor targeting agent (ARTA) with abiraterone plus prednisolone, with apalutamide or with enzalutamide leads to a significant improvement in OS and an increase in the time to transition to castration resistance. The choice of therapy sequence in advanced PCa should be based, among other things, on the side-effect profiles of the substances and patient’s preferences. Within metastatic castration resistant prostate carcinoma (mCRPCa) setting, the therapy with abiraterone, enzalutamide, docetaxel, cabazitaxel and radium-223 is approved and indicated in Europe. Respectively, five substances are available, each of which has led to a significant increase in survival time in phase III studies. The optimal therapy sequence in the mCRPCa stage is still unclear. The current trend in personalised medicine in the next decade in therapy, regarding prostate carcinoma, are poly(ADP)-ribose polymerase (PARP) inhibitors, which are and will be available as an effective therapy option for patients with mutations in DNA repair genes. The most important question is when and how patients should be tested for mutations in DNA repair genes and to which line of therapy will PARP inhibitors belong.

It was concluded that depression (D) is an independent risk factor for cardiovascular diseases (CVD), and is not related to other previously determined cardiac risk factors. Compared with non-depressed patients, the risk of cardiac arrest increased in less severely depressed patients. D worsens the CVD prognosis by significantly increasing the risk of recurrent coronary heart disease (CHD). Some studies suggest that OS directly increases the risk of D in patients with CVD. Oxidative stress (OS) is considered an emergency mechanism that relates to both CVD and D pathophysiology. The common risk factors increase the production of OS and reduce antioxidant defences, thereby promoting the occurrence and development of interacted ischaemic CVD and D. At present, there is insufficient evidence that routine screening of D in patients with CHD will ultimately help improve the patient’s condition. This review reiterates the need for a multidisciplinary approach, which is necessary to understand, diagnose and then treat this frequent co-morbid condition of CHD and D. Assessment of OS markers could modify risk stratification, diagnosis and prevention and treatment of patients with both CHD and D, in patients with and without previous cardiac history.

Found in lakes, freshwater sapropel is a sediment with a fine structure containing more than 10% of organic matter as well as residues of aquatic organisms with a small content of inorganic components of biogenic origin and mixture of mineral ingredients. The mud was first used in medicine by ancient Greeks, and it gained more popularity together with development of balneology in Europe in the 19^th century as a remedy for several diseases. The last century also brought wider popularity in its cosmetic use. Despite its wide usage, mechanisms behind its effects are not so clear yet. Broad but fragmented studies on the effects of sapropel are available, but few have used modern research methods. There is evidence suggesting that its positive health effects are linked to its thermal capacity, ability of penetration in tissues and biological activity of its components, e.g., humic substances. Evidence also suggests antimicrobial activity and positive effects on skin regeneration. This review aims at summarising available knowledge on the structure and composition of sapropel and its effects on the human body, as well as its potential for further evidence-based use in medicine and cosmetics.

The article provides a brief insight in the history of ion implantation, paying special attention to boron ion implantation in high purity Germanium crystal, exclusively valuable in the production of highly effective sensors of high-energy radiation to detect photons in the range of megaelectron-volt or higher up to hard X-ray range. There is a need for small user-friendly implanters in response to urgent demand to scale up production of short wave sensors, which are in exclusive demand for various nuclear safety systems worldwide. Particularly, research driven “high tech” small and medium enterprises in Latvia are among the three leading worldwide producers of such sensors and systems. These SME provide instrumentation to the International Atomic Energy Agency, to the government of Singapore, to the government of Japan to facilitate dealing with nuclear waste management caused by the Fukushima disaster, and to the European Space Agency. The challenge is to find technology that allows the use of solid state boron as ion sources instead of its chemical compounds, which create too many technological difficulties in the beam forming process and in most cases are poisonous. The review of existing solutions points towards a possible breakthrough where hollow cathode plasma combined with radiofrequency inductive coupled plasma can be used to produce boron ions from elemental boron in sufficient quantity to form a high energy ion beam close to 100 kV. Based on the review, promising solutions are offered, the first results of relevant analytic and pilot experiments are analysed and the future experimental roadmap is discussed.

Nanoparticles (NPs) are a wide class of materials, which have at least one dimension less than 100 nm. They are actively used in plant biology research due to their unique physicochemical properties. However, the large-scale application of NPs has led researchers to consider the problems, challenges, and consequences of their environmental effect. The aim of this paper is to summarise current achievements and progress of NP use in plant biotechnology and also to evaluate future implications in this field.

Investigations of biologically active substances sourced from xylotrophic macromycetes have shown their fundamental and practical significance. These studies have promoted the development of biotechnologies by obtaining the valuable products from the mycelial biomass and cultivation liquid and using these fungal species in “white chemistry”. Research into environmentally safe biological methods of stimulating the growth of medicinal and edible mushrooms can assist the development of scientific foundations of culture technologies. From the viewpoint of their bio-technological potential, selected factors of biological origin that promote the growth of wide-scale cultivated basidiomycetes are of interest. Improving mushroom resistance against negative environmental impacts seems to be feasible when the mushroom grows in combination with growth-promoting bacteria. The soil bacteria from the Azospirillum genus have attracted attention, as microorganisms are capable of actively influencing the growth and development of agricultural crops. Thus, revealing and exploring the growth-promoting properties of different species of Azospirillum with respect to edible and/or medicinal mushrooms, as well as the properties promoting the suppression of contaminants in double culture, are believed to be feasible and to reveal undoubted novelty. Cultivation jointly with the beneficial bacteria is a more effective biotechnological method for obtaining this valuable functional food faster, with a greater and much better and maintained mushroom yield. Future work involves addressing the problems of mushroom growth promoting bacterial interactions with mushrooms and implementing these synthetic microbial associations into agriculture.

Modern therapeutic strategies for precancerous cervical intraepithelial neoplasia (CIN) focus on immune-modulatory and cancer vaccination. The local cervical immune status in cervical cancer and CIN could influence HPV infection persistence, progression and carcinogenesis. We analysed the role of FOXP3+ regulatory T lymphocytes, CD4+ and CD8+ T lymphocytes in CIN I, CIN II and CIN III patients with and without HPV infection. Sixty-two patients were enrolled in the study. Each patient underwent a colposcopy-guided cervical biopsy. FOXP3+ lymphocytes and CD4+,CD8+ lymphocytes were detected by immunostaining in tissue samples obtained from a control group (n = 10), patients with CIN I (n = 20), CIN II (n = 14) and CIN III (n = 18) lesions. HPV was assayed by Aptima. The results showed that the numbers of CD4+ T lymphocytes did not differ between patients with CIN I, CIN II, and CIN III. However, patients with CIN II and CIN III had significantly upregulated CD8+T lymphocytes compared to patients with CIN I. In addition, patients with CIN II and CIN III had increased FOXP3 + T lymphocytes compared with patients with CIN I, which was associated with HPV status. Upregulation of FOXP3+ regulatory T lymphocytes and CD8-positive lymphocytes in patients with CIN II and CIN III suggested a pivotal role of T regulatory lymphocytes and CD8+ lymphocytes for counteracting the host immune response in the progression from CIN I to CIN II and CIN III.

Severe pain is a major problem in the early postoperative period after open major upper gastrointestinal surgery. This study aimed to assess the efficiency of rectus sheath block with catheters placed through open access into the retromuscular space in providing effective pain relief. A prospective study was done at Rīga East University Hospital, Latvia. Thirty-nine patients with open gastrectomy were allocated into two groups: 21 patients in the block group and 18 patients in the control group. In the block group, at the end of the operation, two catheters were inserted into the retromuscular plane under the m. rectus abdominis through the open access (using a specially invented technique). After surgery, patients in the block group received continuous 0.125% (10–12 mg/h) bupivacaine infusion through rectus sheath catheters for 72 hours. Patients in the control group received standard postoperative analgaesia. The results showed that postoperative pain at rest was significantly lower in the Block group than in the control group at 48-hour and 72-hour intervals after surgery. Pain on movement in the block group was significantly lower than that in the control group at all postoperative times: at 24, 48, and 72 hours. The median fentanyl requirement range in the postoperative period was significantly lower in the block group (0.5 (0–1.25) mg) than in the control group (2.0 (1.0–3.25) mg (p = 0.001)). Continuous retromuscular rectus sheath infiltration of 0.125% bupivacaine through a rectus sheath catheter after open gastrectomy provides effective postoperative analgaesia in the early postoperative period and significantly reduces opioid consumption.

Inherited peripheral neuropathies (IPN) are a clinically and genetically heterogeneous group of disorders. The most common IPN is Charcot-Marie-Tooth (CMT) disease. Here we describe IPN clinical variability and diagnostic characteristics in the Latvian population. A total of 101 patients were enrolled in the study. Genetic testing consisted of PMP22 copy number analysis and whole-exome sequencing (WES). Clinical assessment comprised CMT Neuropathy Score version 2 (CMTNSv2), CMT Examination Score, pain, anxiety and memory/cognitive ability testing. The diagnostic yields for PMP22 copy number detection and WES were 45.8% and 77.8%, respectively. Disease severity assessment indicated high clinical heterogeneity, with CMTNSv2 scores ranging between 0 and 33. More than one-third of patients reported pain, and it was found to be significantly more common in patients with at least a mild anxiety level. From the initial development of symptoms, on average, it took more than 13 years for a diagnosis of IPN to be confirmed. This study updates the IPN genetic and clinical profile of the Latvian population and demonstrates the presence of a high level of heterogeneity. The time to diagnosis for IPN patients needs to be improved by employing multiplex ligation-dependent probe amplification initially followed by WES.

The success of global strategies to eliminate hepatitis C as a public threat by 2030 depends on local country-wide activities of all involved stakeholders, the most important being general practitioners (GP) and the entire country population. The opinion of currently diagnosed patients can help stakeholders to plan further actions such as addressing new target groups. Our aim was to determine the experiences, opinions, and attitudes of viral hepatitis C (VHC) patients towards the hepatitis C virus (HCV) infection and corresponding healthcare services in Latvia. Questionnaires were distributed by nurses in hospitals of major cities in Latvia. The survey results highlighted the importance of the role of the general practitioner and time from diagnosis to specialist consultation. The majority of respondents were not aware of VHC symptoms, although they were informed about possible complications such as liver cirrhosis and hepatocellular carcinoma. The major VHC patient pool was not composed of drug users, but people who never used narcotics, highlighting the importance to increase VHC awareness in other risk groups and in the general population. Consequently, targeted VHC screening programmes are essential tools in achieving elimination of HCV infection as a public threat in Latvia. The action plans should be updated regularly aiming to strengthening of the GP role and shortening time to consultation with a specialist.

We analysed the age- and sex-specific incidence, disease-stage distribution, treatment modalities, and survival of patients with hepatocellular carcinoma (HCC) in Latvia from 1997 to 2017. Retrospective data from the Cancer Registry of Latvia identified 692 men and 427 women aged >19 years who were diagnosed with HCC, confirmed by autopsy, morphological, radiological, or clinical examinations. The total incidence of HCC increased from 2.63 to 3.75 cases per 100 000 person-years in 1997–2007 and 2008–2017, respectively. It was higher in men and increased with age. Two-thirds (65.9%) of patients were diagnosed with stage IV HCC. Overall, 935 patients died during follow-up. The survival rate was low: 32.5% and 22.2% of patients survived for 6 months and 1 year after diagnosis, respectively. Male sex, older age, and advanced stage at diagnosis were associated with poor prognosis. The proportion of radically treated patients was higher, and survival was better, in the period 2008–2017. Our epidemiological analysis of HCC over 20 years shows that the overall incidence of HCC has been increasing in Latvia since 1997; however, it is similar to that of other European countries. Advanced stage at diagnosis results in a low proportion of radically treated patients and poor overall survival.

In this study, we examined if vacuum drying can be an effective way to remove water from substantia compacta, conducted in order to preserve bones for possible future transplantation. We found a number of interesting results. First, it seemed that vacuum drying removed the most of the water from substantia compacta. Second, we observed that vacuum drying did not damage the histological structure of the samples. These results indicate that vacuum drying might be used to remove water from compact bone, but more studies are required in order to assess how this method affects substantia compacta and also substantia spongiosa.

This paper presents a geospatial analysis of two oceanic trenches using a GMT (Generic Mapping Tools) cartographic method that exploits the scripting approach to visualisation of their geometric shapes. To this end, the research applies the high-resolution datasets GEBCO and ETOPO1 and ETOPO5 for modelling of the submarine relief. This allows taking into account the 2D and 3D shape deviations in the geomorphology of the two selected segments of the trenches by transecting a series of the cross-section profiles. A scripting algorithm of spatial data processing based on the GMT techniques visualised the topography of the submarine objects in 2D and 3D forms and extracted the topographic data from raster grids for statistical analysis of depth using the cross-section transect profiles of both trenches. The bathymetry of the Mariana Trench was evaluated in the southern segment located near the Challenger Deep area, southwest of Guam Island, in comparison with the segment of the Philippine Trench, which was transected in the surroundings of Mindanao Island. The study presented a comparative submarine geomorphic modelling and spatial analysis of the Philippine Sea basin area. The bathymetric analysis of the relief in the Mariana and Philippine trenches showed effective performance of the GMT scripting toolset in advanced cartographic data analysis and visualisation.

There is an increasing need for species occurrence data at a regional level for the global assessment of invasiveness of neophytes. Therefore, the distribution and habitats of Lactuca tatarica (L.) C.A. Mey. in Latvia (Baltic Sea region) was studied. L. tatarica was observed for the first time in Latvia in 1920. During the next 60 years, it was mainly found in synanthropic habitats. Since the 1980s, the species has spread along the Gulf of Riga (the Baltic Sea) coast. In 2019, recent data on the distribution of L. tatarica were obtained in a large-scale habitat mapping project. Lactuca tatarica was observed in 147 polygons (total area of 230 ha) representing nine habitat types of EU importance. The largest proportion of L. tatarica localities was recorded in beach habitats, and the highest abundance and total area in white and grey dunes. Lactuca tatarica was observed in the following associations: Cakiletum maritimae, Honckenyetum peploidis, Elymo-Ammophiletum arenariae, and Festucetum polesicae. In most localities, L. tatarica genets are scattered or in small groups covering small areas. In some coastal sections (southern part of the Gulf), L. tatarica forms dense stands that tend to spread. Lactuca tatarica in Latvia is considered as a neophyte successfully naturalised mainly in coastal dune habitats, and in some locations it corresponds to the criteria of invasive species with a high risk to endanger natural habitats.

The aim of the present study was to evaluate the effect of different levels of mineral nutrient availability on development and physiological performance of several common indoor ornamental plant species (Anthurium sp., Chlorophytum comosum, Epipremnum aureum, Plectranthus fruticosus, Spathiphyllum sp., and Tradescantia pallida) cultivated in hydroponics with potential use in active botanical biofilter systems. Plants were grown in expanded clay granules at four levels of mineral nutrient availability provided by two types of commercial mineral fertiliser. The growth stimulative effect of increased mineral nutrient availability depended on plant growth rate, with a lower effect on slower growing species. The need for nutrients increased in the order Anthurium < Spathiphyllum < Epipremnum < Chlorophytum < Tradescantia < Plectranthus. Tissue water content showed pronounced differences between various plant species as well as between plant organs. For several species, increase in mineral nutrient availability resulted in a significant increase in tissue water content. Chlorophyll fluorescence analysis showed that indoor plants can successfully adapt to low and moderate mineral fertiliser levels with balanced individual nutrient rates, without negative consequences to photochemistry of photosynthesis. Consequently, indoor plants can be cultivated at a relatively low concentration of mineral nutrients for optimum utilisation in active botanical biofilter systems.

The development of new methods of crop production is the most promising field of research in agriculture. There are numerous chemical techniques of seed treatment before sowing; however, mollusc mucus has not been considered as a natural alternative of seed treatment yet. In this study, we treated sweet pepper seeds with Spanish slug mucus before sowing. Seed germination success, germination time, as well as the performance of seedling growth were compared between experimental and control groups. The main result showed that seeds treated with slug mucus required significantly fewer days to germinate than seeds without treatment. Although treated seeds exhibited faster germination, seedlings showed slower growth than in the control group. No significant difference of seed germination success between the control and experimental group was found.

Q-fever is widespread globally. The goal of this study was to estimate the prevalence of Q-fever infection in Latvia among dairy cattle in 2018–2020, in comparison with that in 2012–2015. The shedding of Coxiella burnetii DNA in milk was assessed. Screening of blood samples of abortion cases for the presence of antibodies against Q-fever and testing of aborted fetuses for C. burnetii DNA were also carried out. Additionally, serum samples from clinically healthy cattle, sheep and goat were included. Overall, 18.34% of milk samples were positive, representing 11.02% of all tested sheds. In total, 20.62% of serum samples from the cattle that suffered abortions were positive or suspicious, representing 12.63% of all sheds. Only 3.33% of serum samples from clinically healthy cattle and 3.42% from sheep and goat were positive. The highest proportion of serologically positive and suspicious samples was observed in cattle that suffered abortion with age from three to nine years, and in the first and third gestation period. One dominant genotype of C. burnetii (MST61) was detected. Ruminant import from abroad was identified as a significant risk factor, as well as the dairy cattle population density.

The main goal of this study was to determine the effects of body weight traits during the rearing period on subsequent milk production of primiparous dairy cows using Principal Component Analysis. Data on lactation performance records of 109 Red Steppe dairy cow progeny of six bulls maintained at the State Enterprise “Pedigree Reproducers” Stepove”” (Mykolayiv region, Ukraine), during 2001–2014, were utilised for the present study. Heifer body weight at birth, 3, 6, 9, 12, 15, and 18 months of age was measured. Records of 305-day milk yield (kg), milk fat percentage (%), milk fat yield (kg), monthly milk yield (kg) and milk fat percentage (%) in the 1^st-lactation dairy cows were also available. Principal Components Analysis (PCA) was conducted on the live weights for each heifer between birth and 18 months of age. The first three principal components (PC1-PC3) explained 79.7% of the total variance. Principal component 1 (PC1) showed significant relationship to body weight of heifers at 9, 12, and 15 months of age (post-pubertal period). Body weight at 3 and 6 months of age (pre-pubertal period) had higher scores on the second principal component (PC2). Principal component 3 (PC3) showed significant relationship to body weight of calves at birth. Only groups of heifers with high scores on PC1 and PC2 had significant effect on subsequent milk performance (with the exception of milk fat percentage). Thus, the use of a multivariate technique (Principal Component Analysis) allowed to determine two age intervals of heifers during the rearing period (pre- and postpubertal periods), which were significantly related to subsequent milk production.

Inter-primer binding site (iPBS) molecular retrotransposon-based markers are a universal and simple tool to estimate genetic diversity. The goal of this study was to select highly informative iPBS primers to be used in studies of intraspecific genetic diversity of cloudberry (Rubus chamaemorus L.), a common plant species of the boreal zone, associated with raised bog habitats and transitional bogs. Initially, 75 iPBS primers were screened and three of the most informative primers (indicated by numbers 2298, 2277, and 2229) were selected based on the highest number of polymorphic bands and PIC (polymorphic information content) values. Electrophoretic analysis revealed 34 bands amplified with primer 2229, 25 bands with primer 2298, and 22 bands with primer 2277. The percentage of polymorphic loci ranged from 90.9 to 97.1% and PIC values ranged from 0.4885 to 0.4965, indicating potential of the selected primers to be applied in population genetic studies of R. chamaemorus.

The influence of the housing system on sperm productivity and reproductive capacity of rabbits was studied. Indicators like ejaculate volume, sperm density, activity, and concentration, as well as the percentage of fertility were measured for silver breed rabbits of three coloured lines housed in aggregates “Rabbitax-8” and in a modular rabbit house developed by Mykolayiv National Agrarian University. The highest male sperm productivity and reproductive capacity were found for rabbits housed in aggregates “Rabbitax-8”.