Promocijas darbs

Elektroniskā versija nesatur pielikumusAnotācija Lai gan mieturaļģēm ir liela ekoloģiska nozīme un tās ir plaši izplatītas un sastopamas, Latvijā iepriekš nav veikti mieturaļģu ekoloģijas pētījumi. Turklāt nav arī pētīta mieturaļģu sugu sastopamība un izplatība visā Latvijas teritorijā. Šī pētījuma mērķis ir iegūt datus par mieturaļģu sugām, kas ir sastopamas Latvijā, to izplatību, sastopamību un galvenajiem abiotiskajiem faktoriem, kuri varētu ietekmēt mieturaļģu sastopamību Latvijā. Saldūdens mieturaļģu sastopamība, biotopi un izplatība tika pētīta 173 pētījumu vietās (ezeros, karjeros, dīķos, upēs, grāvjos, avotos, purvu lāmās). Pētījuma laikā konstatētas 18 saldūdens mieturaļģu sugas - 11 Chara, piecas Nitella sugas, Nitellopsis obtusa un Tolypella prolifera. Ļoti reti sastopamas ir Nitella confervacea, N. syncarpa, N. translucens, T. prolifera, reti - Chara strigosa, diezgan bieži - C. filiformis, C. hispida, C. intermedia, C. rudis, C. vulgaris, N. flexilis, N. mucronata, bieži - C. aspera, C. contraria, C. tomentosa, C. virgata, Nitellopsis obtusa un ļoti bieži - C. globularis. Pētījuma laikā ievākti mieturaļģu herbāriji (521 krājuma vienības), kas glabājas Latvijas Dabas muzejā. Izveidota savākto un dāvināto herbāriju publiski pieejama datu bāze (www.meandrs.lv). Herbāriji izmantoti sugu morfoloģisko aprakstu un noteikšanas tabulu izveidei. Visiem pētījumā ievāktajiem sugu herbārijiem tika mērīts minimālais un maksimālais galvenās ass garums un diametrs, īszaru un posmu garums. Konstatētas vairākas mieturaļģu minimālās un maksimālās galvenās ass garuma (Chara aspera, C. hispida, C. intermedia, Nitellopsis obtusa), diametra (C. filiformis), īszaru (C. rudis, C. tomentosa, C. strigosa) garuma atšķirības, salīdzinot ar literatūru. Konstatētās morfoloģisko pazīmju izmaiņas nav būtiskas sugu noteikšanai, bet raksturo Latvijā augošo mieturaļģu daudzveidību un ir būtiskas sugu aprakstu veidošanā. Lai analizētu mieturaļģu ekoloģiju, 78 pētījumu vietās tika noteikti ekoloģiskie faktori (Ca2+, HCO3 -, Mg 2+, N-NO2 -, N-NO3 - un P-PO4 3- koncentrācija, kopējā cietība, pH, ūdens krāsa un ūdens caurredzamība). No visiem pētītajiem faktoriem četri ir statistiski būtiski un saistīti ar sugu sastāva gradientu. Statistiski būtiski faktori, kas ietekmē sugu sastopamību ir HCO3 - (p=0.002) un Mg 2+ (p=0.008) koncentrācija ūdenī, pH (p=0.026) un Seki caurredzamība (p=0.0360).Summary Irrespective of the great ecological importance of charophytes and their widspread distribution and occurrence in Latvia, no investigations have been carried out of charophyte ecology in Latvia before. Also the occurrence and distribution has not been studied in the whole territory of Latvia. The aim of this study is to summarize information about charophyte species in Latvia, study their distribution and occurence and examine the main abiotic factors influencing charophyte occurrence in Latvia. In 173 localities (lakes, pits, ponds, rivers, ditches, springs, bog pools) data on freshwater charophyte occurrence, habitats and distribution was collected. In total 18 freshwater charophytes species were found during the investigation - 11 Chara, five Nitella species, Nitellopsis obtusa and Tolypella prolifera. Very rare are species Nitella confervacea, N. syncarpa, N. translucens, T. prolifera, rare - Chara strigosa, quite common - C. filiformis, C. hispida, C. intermedia, C. rudis, C. vulgaris, N. flexilis, N. mucronata, common - C. aspera, C. contraria, C. tomentosa, C. virgata, Nitellopsis obtusa and very common - C. globularis. During the investigation charophyte herbaria were collected (521 herbaria units). The herbaria are stored in Latvian Museum of Natural history. A publicly available data base (www.meandrs.lv) of collected and presented herbaria was made. Herbaria was used for development of species morphological descriptions and identification keys. Minimal and maximal length of algae, diameter of main axis, length of branchlets and internodes were measured for all collected herbaria. Some differences of minimal and maximal length of algae (Chara aspera, C. hispida, C. intermedia, Nitellopsis obtusa), diameter of main axis (C. filiformis), length of branchlets (C. rudis, C. tomentosa, C. strigosa) in comparison with the literature was found. The described differences in morphological features are not essential for species identification, but characterize the diversity of charophytes growing in Latvia and are important for preparing species descriptions. In 78 localities ecological factors of water (Ca2+, HCO3 -, Mg 2+, N-NO2 -, N-NO3 - and P-PO4 3- concentration, total hardness in water, pH, water colour and water transparency) were analized to study Charophyta ecology. From all analized factors four were statistically significant and associatedted with gradients of species composition. Significant factors affecting species occurrence were HCO3 - (p=0.002) and Mg 2+ (p=0.008) concentration in the water, pH (p=0.026) and Secchi depth (p=0.0360)

Taxonomic features of fruits and seeds of Nymphaea and Nuphar taxa of the Southern Baltic region

Research was carried out on fruits and seeds of Nymphaea and Nuphar taxa collected from Poland, Latvia and Estonia. The aim of the research was to establish diagnostic features which could enable identification of the examined taxa on the basis of the fruit and seed structure and creating a key to identify them. The examined organs were observed through an optic microscope and scanning electron microscope (SEM). New diagnostic features were discovered: spotting of fresh pericarp, the range of the fruit shape coefficient, the colour of the rays in the fruit stigma disc, the thickness of the seed testa, ribs in the seeds, and occurrence of the “puzzle shaped” cells on the surface of the testa. The discovered features were used in the taxonomic characteristics

Laboratory Tests in Addition to the Alvarado Score in the Management of Acute Appendicitis in School-Age Children

Funding Information: The study was financially supported by a Grant No. 2010.10-4/VPP-4 of the framework of the Latvian National Programme and Grant No. 2009/0147/1DP/1.1.2.1.2/09/ IPIA/VIAA/009 from the project Support for Doctoral and Post-doctoral Investigations Rîga Stradiòð University fellowship. Publisher Copyright: © 2019 Astra Zviedre et al., published by Sciendo 2019.The aim of the study was to determine whether the Alvarado score (AS) together with laboratory tests could be used to distinguish patients with acute appendicitis (AA) from acute mesenteric lymphadenitis (AML). Fifty-seven patients (7-18 years) with suspected AA were included in the prospective study (October 2010 - October 2013). Thirty-one patients underwent surgery for AA and 26 were not treated surgically and were diagnosed AML on ultrasonography. AS, white blood cell count (WBC), C - reactive protein (CRP) and serum cytokines (EGF, IL-10, IL-12(p70), IL-1β, IL-4, IL-6, IL-8, IL-17, MCP-1, TNF-α) were obtained on admission and were compared between groups. Mean age of the 57 patients was 12.9 (SD 3.2). Accuracy (AR) for AS ≥ 7 alone was 73.7% for AA. Modified AS with certain serum cytokines seemed to be a reliable tool for initial differential diagnosis between AA and AML in school-age children. Based on these results, AS ≥ 7, WBC ≥ 10.7 × 103/μL and serum IL-6 ≥ 4.3 pg/mL assessed altogether will yield more sensitivity for AA. Also for further advanced diagnostics, we propose to take into account the serum IL-6, IL-8, MCP-1, CRP cut-off levels in the differential diagnosis between complicated and uncomplicated AA to decide whether the treatment should be conservative or surgical.publishersversionPeer reviewe

Prenatal and postnatal diagnostics problems of the most common surgical congenital malformations of newborns in Latvia

The most common surgical congenital malformations of newborns in Latvia are esophageal atresia (EA) with or without tracheoesophageal fistula (TEF), duodenal atresia (DA) and abdominal wall defects - gastroschisis (G) and omphalocele (O). Survival and quality of life of these patients depend on precise pre- and postnatal diagnosis, timely and qualified treatment, and presence of associated anomalies and prematurity. The aim of our study was to define prenatal and postnatal diagnostic problems of the most common surgical congenital malformations of new-borns in Latvia. Data concerning pre- and postnatal diagnostics from case-records of patients treated in Children's Clinical University Hospital from 1998 till 2008 with esophageal atresia (58 patients), duodenal atresia (20 patients) and congenital abdominal wall defects - gastroschisis (17 patients) and omphalocele (28 patients) were analysed. Results showed that in case of EA prenatal USG was performed in 62% of expectant mothers and in neither case suspicion about. EA was expressed. In all patients after birth diagnostic placement of nasogastric tube was performed. In approximately one-third catheter of bad opaqueness was used. Preoperative bronchoscopy and esophagoscopy in order to exclude upper tracheoesophageal fistula were performed in two patients from the analysed group. In 40% of cases DA was diagnosed in prenatal ultrasonography. G was diagnosed prenatally in 29.4%, O - only in 3.7%.publishersversionPeer reviewe

Different Cytokine Profiles in Children with Acute Appendicitis and Acute Mesenteric Lymphadenitis

The aim of this study was to investigate the role of serum cytokines in the diagnosis of acute appendicitis (AA) and acute mesenteric lymphadenitis (AML). Data were collected prospectively on 7 to 18 year old children (October 2010 - October 2013): 31 patients with AA, 26 patients with AML, and 17 patients with elective non-inflammatory surgical disease were selected as controls. Serum levels of IL-10, IL-12(p70), IL-1β, IL-4, IL-6, IL-8, IL-17, MCP-1, EGF, TNF-α were measured. Patients with AA had significantly increased serum levels of IL-6(1) (z = -3.72; p = 0.0002) and IL-10(1) (z = -2.81; p = 0.005) compared to AML before any treatment. The consecutive measurements of MCP-1 in serum demonstrated a significant difference within 72 hours in the AA group (Wilks' Lambda test 0.80; F(2;29) = 3.5; p = 0.04) and also in the AML group (Wilks' Lambda test 0.70; F(2;24) = 5.0; p = 0.01). The increased values of IL-6 and IL-10 were the most reliable cytokines one hour before surgical intervention for patients with AA. MCP-1 values changed significantly within 72 hours after patient hospitalisation but did not differ between the groups, and could not be a helpful serum biomarker in distinguishing patients with AA and AML.Peer reviewe

catena-Poly[sodium(I)-μ-tetra­butoxy­borato]

The title compound, [Na(C16H36BO4)]n, has a fourfold axis passing through the Na and B atoms which both are bound by four O atoms. The tetra­butoxy­borate anion provides the bridging to form one-dimensional polymers running along [001], just like those found for the tetra­ethoxy­borate structure. The two but­oxy ‘tail’ atoms are disordered over two conformations in a 0.887 (9):0.113 (9) ratio

Surgical and non-surgical treatment of paediatric appendicitis : can algorithms help us to predict perforation?

The recent interest in and evidence of non-surgical treatment with antibiotic therapy has led to therecurring issue of differentiating acute no-complicated appendicitis (AnA) and acute complicated appendicitis (AcA) when these are presented in an emergency department. To create the initial version of an acute appendicitis (AA) diagnostic and treatment algorithm, we analysed treatment results of 178 children with AnA and AcA treated at the Children’s Clinical University Hospital in Riga in the period between 2010 and 2013. Evaluation of the clinical symptoms, laboratory and radiological findings was included in development of the algorithm. The algorithm was created in 2016 and accepted by the hospital administration. We present the algorithm’s updated version of 2020. The introduction of diagnostic scores and algorithms has standardised and improved the diagnosis of paediatric AA. New diagnostic tests with higher sensitivity and specificity may improve the accuracy of diagnostic algorithms. Measuring multiple effective biomarkers simultaneously may improve the accuracy of diagnostic algorithms and predict the severity of paediatric AA. Machine learning algorithms may be able to process a much larger amount of data and provide afaster conclusion, helping the surgeon make the right decision in diagnosing appendicitis in children and prevent unnecessary surgery.publishersversionPeer reviewe

Variability of COVID-19 and MIS-C Related Abdominal Surgical Presentations in Children: Case Report Series

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A Unique Type or Variation of Bile Duct Cyst in a 9-Year-Old Girl:A Remarkable Case Study

Patients with bile duct cysts require careful radiological assessment of the hepatobiliary system prior to surgical intervention. This clinical case is uncommon with an atypical clinical presentation and radiological findings. According to the most widely used classification of choledochal cysts, this case presents a combination of Type I and Type IV of choledochal cyst (CC) combining the form of extra, intrahepatic bile ducts and cystic duct dilations

Case series of variable acute appendicitis in children with sars-cov-2 infection

Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This case series study consists of six children, aged 5–16 years, admitted to a centralized tertiary paediatric hospital serving a population of 1.9 million with acute appendicitis in the setting of SARS-CoV-2 infection. From the beginning of the pandemic in March 2020 until August 2021, 121 COVID-19-positive children were admitted to the hospital. A total of 49 (40.5%) of these patients presented with gastrointestinal symptoms, of which six were diagnosed with acute appendicitis. Five underwent an appendectomy, while one was treated conservatively. To date, it has been reported that appendicitis may have a plausible association with SARS-CoV-2 infection in children. With COVID-19 cases rising, every medical specialist, including all paediatric surgeons, must be ready to treat common acute diseases with SARS-CoV-2 infection as a comorbidity. Providers should consider testing for this infection in paediatric patients with severe gastrointestinal symptoms. Non-surgical treatment of acute appendicitis in children may gain new importance during and after the COVID-19 pandemic. Further studies are needed to prove the link of causality between COVID-19 and acute appendicitis in children.publishersversionPeer reviewe