Aspects of the composition, pigments and carbon fixation of marine phytoplankton

The seasonal variation of phytoplankton biomass in terms of total number of algal cells, chlorophyll a levels and phytoplankton productivity was investigated in the years 1984, 1985, 1986 and 1987 for samples collected from the photic zone (surface and 5 metres depth) at stations 11 and 9, at the Fairlie Channel in relation to the changes in nutrient levels and weather conditions. The seasonal variation in the phytoplankton composition was assessed using microscopic examination of the samples and the qualitative analysis of the different algal pigments. Also investigated was the contribution of the different phytoplankton size fractions to the total photosynthetic activity, including that of net -, nano - and picophytoplankton. Although there is a year to year slight variability in weather conditions and nutrient concentrations during the course of this investigation, certain features recurred annually: 1) The spring diatom increase (spring bloom) occurred in March or early April. 2) The phytoplankton biomass during the summer fluctuated about intermediate levels, althoughon certain occasions they were comparable or higher than those observed during the spring diatom increase and during this period the minimum nutrient levels were recorded. The maximum photosynthetic activities were found during the summer period (1986) in reflection of the favourable weather conditions marking this period. 3) Small to relatively high standing crop levels were recorded during the autumn period with photosynthetic activities comparable to those found during the summer. Relatively high nutrient levels were recorded during the autumn. 4) Low phytoplankton biomass (representing the year minimum) and high nutrient concentrations (representing the year maximum) were found during winter. There was no regular recurring autumnal bloom. With the exception of the findings on 25 May and 6 June, 1984 when the benthic organisms represented a large part of the total population, these organisms were found to be most numerous during autumn and winter months, coinciding with the prevailing conditions. Diatoms were the most dominant fraction of the population mainly during the spring diatom increase of which Skeletonema costatum and Thalassiosira nordenskioldii were the most dominant species; also observed in considerable numbers was Navicula spp. The largest levels of contribution by dinoflagellates to the total phytoplankton biomass were recorded during the autumn months; the dinoflagellate fraction was predominantly composed of the genus Ceratium. Green flagellates were found in considerable numbers during the summer months although they were common in the autumn and winter months of 1986. The seasonal variations of the total phytoplankton biomass and nutrient levels were similar to those observed in the past in the Fairlie Channel. (Abstract shortened by ProQuest.)

Građevinski materijal kao performansa održive arhitekture u funkciji vrednovanja jedinice susedstva

Evolucija tehnologije materijala u poslednjim decenijama rezultirala je zanimljivim projektima usmerenim na očuvanje životne sredine, energije i smanjenje zagađenja. Načela modelovanja životne sredine uzeta su kao osnova za arhitektonsku misao, počev od ranih faza procesa projektovanja, završavajući odabirom odgovarajućeg građevinskog materijala za postizanje održivih zgrada. Problem je što su ova nastojanja ograničena u našem lokalnom okruženju i nisu shvaćena sa potrebnom ozbiljnošću. Istraživački problem se javlja usled zanemarivanje ekološkog aspekta (ekološkog sistema) prilikom odabira građevinskih materijala tokom procesa projektovanja za postizanje održivih zgrada. Cilj ovog istraživanja je otkrivanje mehanizama odabira građevinskih materijala radi poboljšanja funkcionalnih performansi i smanjenja negativnih uticaja na životnu sredinu i očuvanja njenih resursa i ekoloških sistema što je višemoguće prema ovim pokazateljima. Uvažavanje elemenata kao što su utelovljena energija, recikliranje i trajnost, ima za cilj da pomogne arhitektama i određenim inženjerima u donošenju odluka koje imaju značajan uticaj na postizanje nivoa održivosti objekata u lokalnom okruženju i mogućnost primene u Libiji. Hipoteza istraživanja rezimirana je u činjenici da je u savremenom pristupu projektovanju i rekonstrukciji objekata u građenoj sredini neophodno definisati nove metodološke i projektantske modele materijalizacije usklađene sa principima održive arhitekture. Primenjeni naučni metod je ispitivanje/eksploratorno istraživanje, u kome se preko modaliteta vrednosti posmatranih objekata, analizira predmet istraživanja u cilju provere naučne hipoteze i otkrivanja naučnog doprinosa

Hyperinsulinism-hyperammonaemia syndrome: novel mutations in the GLUD1 gene and genotype-phenotype correlations

Background: Activating mutations in the GLUD1 gene (which encodes for the intra-mitochondrial enzyme glutamate dehydrogenase, GDH) cause the hyperinsulinism–hyperammonaemia (HI/HA) syndrome. Patients present with HA and leucine-sensitive hypoglycaemia. GDH is regulated by another intra-mitochondrial enzyme sirtuin 4 (SIRT4). Sirt4 knockout mice demonstrate activation of GDH with increased amino acid-stimulated insulin secretion. Objectives: To study the genotype–phenotype correlations in patients with GLUD1 mutations. To report the phenotype and functional analysis of a novel mutation (P436L) in the GLUD1 gene associated with the absence of HA. Patients and methods: Twenty patients with HI from 16 families had mutational analysis of the GLUD1 gene in view of HA (n=19) or leucine sensitivity (n=1). Patients negative for a GLUD1 mutation had sequence analysis of the SIRT4 gene. Functional analysis of the novel P436L GLUD1 mutation was performed. Results: Heterozygous missense mutations were detected in 15 patients with HI/HA, 2 of which are novel (N410D and D451V). In addition, a patient with a normal serum ammonia concentration (21 µmol/l) was heterozygous for a novel missense mutation P436L. Functional analysis of this mutation confirms that it is associated with a loss of GTP inhibition. Seizure disorder was common (43%) in our cohort of patients with a GLUD1 mutation. No mutations in the SIRT4 gene were identified. Conclusion: Patients with HI due to mutations in the GLUD1 gene may have normal serum ammonia concentrations. Hence, GLUD1 mutational analysis may be indicated in patients with leucine sensitivity; even in the absence of HA. A high frequency of epilepsy (43%) was observed in our patients with GLUD1 mutations

Genetic background of primary and familial HLH in Qatar: registry data and population study

BackgroundFamilial hemophagocytic lymphohistiocytosis (FHLH) is an inherited life-threatening disease. Five types are identified, with the addition of congenital immunodeficiency syndromes in which HLH is a typical manifestation. The literature on this disease is very scarce in the Middle East, with only a few scattered reports.MethodsWe report detailed demographic, clinical, and genomic data from 28 patients diagnosed with primary and familial HLH over the last decade in Qatar. An evaluation was performed of allele frequencies of deleterious variants from 12 primary and familial HLH causative genes on the Qatar Genome Programme (QGP) cohort of 14,669 Qatari individuals.ResultsThe genetic diagnosis was obtained in 15 patients, and four novel mutations in Perforin 1 (PRF1), UNC13D, LYST, and RAB27A genes were found. We identified 22,945 low/high/moderate/modifier impact variants significantly enriched in the QGP in those 12 genes. The variants rs1271079313 in PRF1 and rs753966933 in RAB27A found in our patient cohort were significantly more prevalent in the QGP compared to the Genome Aggregation Database (gnomAD) database, with a high carrier frequency in the Qatari population.ConclusionsWe established the first primary and familial HLH Registry in the Gulf Region and identified novel possibly pathogenic variants present at higher frequency in the Qatari population, which could be used for screening purposes. Raising awareness about primary and familial HLH and implementing screening activities in the Qatari highly inbred population could stem into more comprehensive premarital and prenatal evaluations and faster diagnosis

Effect of Revascularization on Intramuscular Vascular Endothelial Growth Factor Levels in Peripheral Arterial Disease

Vascular endothelial growth factor (VEGF) is a potent driver of angiogenesis, which may help to relieve ischemia in peripheral arterial disease (PAD). We aimed to investigate the role of intramuscular VEGF in ischemic and non-ischemic skeletal muscle in PAD patients before and after surgical or endovascular revascularization and different stages of PAD. Biopsies of the gastrocnemius and vastus muscles from twenty PAD patients with stenosis or occlusion of the superficial femoral artery were obtained both during revascularization and 8 weeks postoperatively. The gastrocnemius muscle was considered ischemic, while vastus muscle biopsies served as intraindividual controls. The levels of vascular endothelial growth factor in muscle lysates were then determined by ELISA. Preoperative VEGF levels were significantly higher in ischemic muscles compared to the controls (98.07 ± 61.96 pg/mL vs. 55.50 ± 27.33 pg/mL, p = 0.004). Postoperative values decreased significantly (p = 0.010) to 54.83 ± 49.60 pg/mL in gastrocnemius biopsies. No significant change was observed in vastus muscle biopsies, with mean postoperative VEGF values found at 54.16 ± 40.66 pg/mL. Since all patients still had indications for revascularization, impairment of angiogenesis mechanisms can be assumed. More research about angiogenesis in PAD is needed with the ultimate goal to improve conservative treatment

The Frequencies of Different Inborn Errors of Metabolism in Adult Metabolic Centres: Report from the SSIEM Adult Metabolic Physicians Group

There are few centres which specialise in the care of adults with inborn errors of metabolism (IEM). To anticipate facilities and staffing needed at these centres, it is of interest to know the distribution of the different disorders

Is Adherence to Imatinib Mesylate Treatment Among Patients with Chronic Myeloid Leukemia Associated with Better Clinical Outcomes in Qatar?

Background: Despite the revolutionary success of introducing tyrosine kinase inhibitors (TKIs), such as imatinib mesylate (IM), for treating chronic myeloid leukemia (CML), a substantial proportion of patients' treatments fail. Aim: This study investigates the correlation between patient adherence and failure of TKIs' treatment in a follow-up study. Methods: This is a follow-up study of a new cohort of CML patients. Adherence to IM is assessed using the Medication Event Monitoring System (MEMS 6 TrackCap, AARDEX Ltd). The 9-item Morisky Medication Adherence Scale, medication possession ratio (MPR) calculation, and the electronic medical records are used for identifying potential factors that influence adherence. Clinical outcomes are assessed according to the European LeukemiaNet 2013 guidelines via reverse transcriptase quantitative polymerase chain reaction measurement of the level of BCR-ABL1 transcripts in peripheral blood. Response is classified at the hematological, cytogenetic, and molecular levels into optimal, suboptimal, or failure. Results: A total of 36 CML patients (5 citizens and 31 noncitizen residents) consented to participate in the study. The overall mean MEMS score was 89. Of the 36 patients, 22 (61%) were classified as adherent (mean: 95) and 14 (39%) were classified as nonadherent (mean: 80.2). Adherent patients were significantly more likely to obtain optimal response (95%) compared to the nonadherent group (14.3%; P < 0.0001). The rate of poor adherence was as high as 39% using MEMS, which correlates with 37% treatment failure rate. The survey results show that 97% of patients increased the IM dose by themselves when they felt unwell and 31% of them took the missing IM dose when they remembered. Other factors known to influence adherence show that half of patients developed one or more side effects, 65% of patients experienced lack of funds, 13% of patients declared unavailability of the drug in the NCCCR pharmacy, and 72% of patients believed that IM would cure the disease. The MPR results reveal that 16% of patients had poor access to treatment through the hospital pharmacy. Discussion and conclusion: This is the first prospective study to evaluate CML patients' adherence and response to IM in Qatar. The high rate of treatment failure observed in Qatar is explained by poor adherence. An economic factor (unaffordable drug prices) is one of the main causes of nonadherence and efforts should be made locally to improve access to medication for cancer diseases. Other risk factors associated with poor adherence could be improved by close monitoring and dose adjustment. Monitoring risk factors for poor adherence and patient education that include direct communication between the health-care teams, doctors, nurses, pharmacists, and patients are essential components for maximizing the benefits of TKI therapy and could rectify this problem. The preliminary results show that patients' response to treatment may be directly linked to patients' adherence to treatment. However, further in-depth and specific analysis may be necessary in a larger cohort