Role of Symmetry in Hisactophilin Folding

Hisactophilin is a histidine-rich actin binding protein from Dictyostelium discoideum; it is a member of the β-trefoil superfamily and exhibits a characteristic tertiary structure with three-fold symmetry. The effect of various mutations on stability and folding of other β-trefoil proteins has been studied and certain mutations that increase sequence and structural symmetry were found to increase protein stability. This study focuses on the effects of point mutations that increase symmetry on hisactophilin stability and folding designed within the core, minicore and turns of conserved and unconserved residues. The stability and folding of hisactophilin mutants were analyzed both thermodynamically and kinetically using fluorescence spectroscopy and circular dichroism (CD) at pH 6.7, 7.7, and 8.7. The stability of each mutant was measured and compared with the wild type protein (WT), and with data obtained for another β-trefoil protein, Fibroblast Growth Factor (FGF). The folding of WT and mutant hisactophilin was found to be reversible by chemically induced denaturation. Both the equilibrium and kinetic data in urea for WT and mutant hisactophilin can be analyzed using a 2-state model for the transition between the folded and unfolded state. The results indicated that H90G and I85L are more stable than the WT due to increase in the folding rate, while I93L is slightly less stable than the WT due to an increase in the unfolding rate. F6L is more markedly less stable than the WT as indicated by urea denaturation; due to protein precipitation the kinetic analysis was not performed for this mutation. F13Ymutation is less stable than the WT from CD result. and it needs investigation with DSC to confirm the stability as indicated as a future work. The results of the mutations support the notion of increased symmetry resulting in increased stability

An investigation of the determinants of plasma glucose and micronutrient concentrations in patients with critical illness

This thesis describes a series of observational studies that examine the relationship between the systemic inflammatory response, glucose, micronutrients concentrations and outcomes in patients with critical illness with reference to a large nutrition screen cohort. Data and stored samples were available from cohorts which had been defined previously. The critical illness cohort comprised of medical or surgical patients ≥ 18 years admitted to the Intensive Care Unit (ICU) of the Glasgow Royal Infirmary (GRI) between September 2006 and December 2008. The nutrition screen cohort comprised samples and associated information which had been processed by the Pathological Biochemistry Department of the GRI. The samples had been received for vitamin and / or trace element assessment of patients from both GRI and other Scottish hospitals between January 2006 and March 2013. Samples had been referred to the lab for analysis of a number of variables related to nutrition, including glucose, albumin, C-reactive protein (CRP), lutein, lycopene, vitamins A, B1, B2, B6, C, D and E, and zinc, selenium, copper, and manganese. Data was not available for all variables for all samples, hence studies varied in the number of observations. plasma glucose was measured in sodium floride blood sample whole-blood samples underwent for routine analysis of concentrations of lutein, lycopene, α-carotene and β-carotene, 25-hydroxyvitamin D (25 (OH) D), ascorbic acid (vitamin C), α-tocopherol (vitamin E) in plasma, zinc, selenium, copper, B1, B2, B6 in plasma and red cells. In Chapter 2 the relationship between glucose and markers of the systemic inflammatory response was examined in detail in patients from the critical illness cohort (n=100). The results of this study showed that plasma glucose concentration - even within the context of tight insulin protocol - was influenced by many factors. Surgical and medical patients differed in their requirements for insulin; medical patients have higher plasma glucose and insulin administration accordingly compared with surgical patients. However, catecholamine and steroid administration were also associated with higher insulin requirements. In Chapter 3 the relationship between plasma asymmetric dimethylarginine (ADMA) and related arginine metabolism (homoarginine, arginine, symmetric dimethylarginine (SDMA)) and outcome was examined in patients from critical illness cohort (n=104). Patients with critical illness experience metabolic disorders including catabolism and hyperglycaemia and these were associated with poor outcome. Plasma ADMA and SDMA concentrations were higher in patients with critical illness and were also associated with disease severity and mortality. In contrast, plasma homoarginine concentrations were lower in patients with critical illness and were also associated with disease severity and mortality. These results suggest that ADMA metabolism is perturbed with likely knock on effects on nitric oxide synthase (NOS) and endothelial function. There is a need for further work on in vivo dimethylaminohydrolase (DDAH) activity in critical illness and the effect of critical illness on the cationic amino acid transporters (CAT)-mediated exchange of ADMA between intra and extra-cellular compartments. It was proposed that ADMA and SDMA may not only be indicators of the severity of illness and may even contribute to adverse events in patients with critical illness. In Chapter 4 the relationship between markers of the systemic inflammatory response, as evidenced by CRP and albumin, and mortality, in patients from critical illness cohort (n=261) was examined. In this cohort, the combination of CRP and albumin predicted ICU and hospital mortality as effectively as APACHE II. In Chapter 5 the relationship between markers of the systemic inflammatory response and plasma glucose was examined in a nutrition screen cohort (n=5248). The results of this study showed that plasma concentrations of glucose were independently positive and negative associated with both CRP and albumin respectively, and were consistent with the systemic inflammatory response as having an impact on glucose concentrations. However, such relationships were not apparent in patients with critical illness (n=116). It was concluded that plasma concentrations of glucose were independently associated with both CRP and albumin, and were consistent with the systemic inflammatory response as a determinant of its concentrations. In Chapter 6 the relationship between markers of the systemic inflammatory response and plasma concentrations of carotenoids was examined in a nutrition screen cohort (n=1074). The results of this study showed that the clinical interpretation of plasma carotenoids requires knowledge of the magnitude of the systemic inflammatory response, even after adjustment for cholesterol. It was concluded that a reliable clinical interpretation can be made only for plasma lutein, lycopene and β-carotene if the CRP is less than 20 mg/L. In Chapter 7 the relationship between markers of the systemic inflammatory response and plasma 25-hydroxyvitamin D (25(OH) D) was examined in a nutrition screen cohort (n=5327, and in patients from critical illness cohort n=117). The results of this study showed that plasma concentrations of 25(OH) D were independently associated with both CRP and albumin. It was concluded that the systemic inflammatory response was a major confounding factor in determining vitamin D status. In Chapter 8 the relationship between markers of the systemic inflammatory response and plasma vitamin E (α-tocopherol) and vitamin C (ascorbic acid) was examined in a nutrition screen cohort (n=359, n=494 respectively and in patients from critical illness cohort n= 82). The results of this study showed that α-tocopherol/ cholesterol ratio and ascorbic acid were independently associated with both CRP and albumin. It was concluded that the systemic inflammatory response was a major confounding factor in determining vitamin E and C status. In Chapter 9 the relationship between markers of the systemic inflammatory response and plasma zinc, selenium was examined in a nutrition screen cohort (n=743, n=833, respectively and in patients from the critical illness cohort n= 114). The results of this study showed that plasma concentrations of zinc were associated with both CRP and albumin. However, the impact of the systemic inflammatory response (as evidenced by elevation of CRP concentrations) on plasma zinc concentrations could be largely adjusted by albumin concentrations. Plasma concentrations of selenium were associated with both CRP and albumin. However, the impact of the systemic inflammatory response on plasma selenium concentrations could not be reasonably adjusted by albumin concentrations. It was concluded that plasma zinc and selenium concentrations were independently associations with CRP and albumin as markers of systemic inflammatory response. In Chapter 10 the relationship between markers of the systemic inflammatory response and red cell zinc, selenium and copper was examined in patients from critical illness cohort (n= 125). The results of this study showed that altered red cell concentrations of zinc, selenium and copper were likely to be more reliable measures of status in the presence of a systemic inflammatory response. In Chapter 11 the relationship between markers of the systemic inflammatory response and red cell vitamins B1, B2 and B6 was examined in nutrition screen cohort (n= 553, n=251, n= 313, respectively and in patients from critical illness cohort n=94). The results of this study showed that in contrast to plasma concentrations of B1, B2 and B6, red cell concentrations do not fall as a part of the systemic inflammatory response. It was concluded that red cell concentrations of B1, B2 and B6 were likely to be more reliable measures of status in the presence of a systemic inflammatory response. In summary, studies in the present thesis showed that, during the systemic inflammatory response, plasma concentration of glucose had multiple determinants other than insulin. Furthermore, in the presence of systemic inflammatory response, plasma lutein, lycopene, α-carotene and β-carotene, 25 (OH) D, C, E, zinc, selenium, and copper were unreliable, and that intracellular micronutrients concentrations such as red cell zinc, selenium, copper, B1, B2 and B6, were more reliable as indicators of vitamin and trace element status in patients subject to nutrition screen and in patients with critical illness. These results have implications for the assessment of glucose and micronutrient status in the general population and for treatment in patients with critical illness

Erythrocyte concentrations of B1, B2, B6 but not plasma C and E are reliable indicators of nutrition status in the presence of systemic inflammation

Background & aim: There is increasing evidence that the plasma concentration of vitamin D, carotenoids, zinc and selenium are associated with the magnitude of the systemic inflammatory response. In order to examine whether other vitamins may be affected and whether red cell concentrations are less affected by systemic inflammation the aim of the present study was to examine the effect of the systemic inflammatory response on red cell measurements of vitamins B1, B2 and B6, and plasma concentration of vitamin C and E in a large cohort of patients referred for a nutritional screen. Methods: Patients referred for nutritional assessment of B1 (n = 551), B2 (n = 251), B6 (n = 313), ascorbic acid (n = 494) and α-tocopherol (n = 395) concentrations. These vitamins were measured using routine laboratory methods. Results: The median concentrations of vitamin B1 grouped according to C-reactive protein concentrations ≤10, 11–80 and >80 mg/L were 543, 664 and 766 ng/g Hb respectively (p < 0.001, 41% higher). The median concentration of vitamin B1 grouped according to albumin concentrations ≥35, 25–34 and <25 g/l were 547, 664 and 701 ng/g Hb respectively (p < 0.001, 28% higher). The median concentrations of red cell vitamin B2 grouped according to CRP concentrations ≤10, 11–80 and >80 mg/L were 2.2, 2.3 and 2.4 nmol/g Hb respectively (p < 0.001, 9% higher). The median red cell concentrations of vitamin B2 grouped according to albumin concentrations ≥35, 25–34 and <25 g/l were 2.1, 2.4 and 2.3 nmol/g Hb respectively (p < 0.001, 14% higher). The median concentrations of red cell vitamin B6 grouped according to CRP concentrations ≤10, 11–80 and >80 mg/L were 534, 548 and 767 pmol/g Hb respectively (p < 0.001, 44% higher). The median red cell concentrations of vitamin B6 grouped according to albumin concentrations ≥35, 25–34 and <25 g/l were 462, 644 and 840 pmol/g Hb respectively (p < 0.001, 82% higher). In contrast, the median plasma concentrations of ascorbic acid grouped according to CRP concentrations ≤10, 11–80 and >80 mg/L were 25.0, 15.0 and 6.0 μmol/l respectively (78% lower, p < 0.001). The median plasma concentrations of ascorbic acid grouped according to albumin concentrations ≥35, 25–34 and <25 g/l were 32.0, 13.0 and 5.0 μmol/l respectively (84% lower, p < 0.001). The median α-tocopherol/cholesterol grouped according to CRP concentrations ≤10, 11–80 and >80 mg/L were 5.9, 4.6 and 2.1 μmol/l respectively (64% lower, p < 0.001). The median α-tocopherol/cholesterol grouped according to albumin concentrations ≥35, 25–34 and <25 g/l were 6.0, 5.5 and 2.1 μmol/l respectively (65% lower, p < 0.001). Conclusion: Red cell concentrations of vitamins B1, B2 and B6 were not lower with an increasing systemic inflammatory response. In contrast, plasma concentrations of vitamin C and E were lower. Therefore, compared with plasma concentration, red cell concentrations of B1, B2 and B6 are likely to be more reliable measures of status in the presence of a systemic inflammatory response

The effect of the systemic inflammatory response on plasma vitamin 25 (OH) D concentrations adjusted for albumin

<b>Aim</b><p></p> To examine the relationship between plasma 25(OH)D, CRP and albumin concentrations in two patient cohorts.<p></p> <b>Methods</b><p></p> 5327 patients referred for nutritional assessment and 117 patients with critical illness were examined. Plasma 25 (OH) D concentrations were measured using standard methods. Intra and between assay imprecision was <10%.<p></p> <b>Result</b><p></p> In the large cohort, plasma 25 (OH) D was significantly associated with CRP (rs = −0.113, p<0.001) and albumin (rs = 0.192, p<0.001). 3711 patients had CRP concentrations ≤10 mg/L; with decreasing albumin concentrations ≥35, 25–34 and <25 g/l, median concentrations of 25 (OH) D were significantly lower from 35 to 28 to 14 nmol/l (p<0.001). This decrease was significant when albumin concentrations were reduced between 25–34 g/L (p<0.001) and when albumin <25 g/L (p<0.001). 1271 patients had CRP concentrations between 11–80 mg/L; with decreasing albumin concentrations ≥35, 25–34 and <25 g/l, median concentrations of 25 (OH) D were significantly lower from 31 to 24 to 19 nmol/l (p<0.001). This decrease was significant when albumin concentration were 25–34 g/L (p<0.001) and when albumin <25 g/L (p<0.001). 345 patients had CRP concentrations >80 mg/L; with decreasing albumin concentrations ≥35, 25–34 and <25 g/l, median concentrations of 25 (OH) D were not significantly altered varying from 19 to 23 to 23 nmol/l. Similar relationships were also obtained in the cohort of patients with critical illness.<p></p> <b>Conclusion</b><p></p> Plasma concentrations of 25(OH) D were independently associated with both CRP and albumin and consistent with the systemic inflammatory response as a major confounding factor in determining vitamin D status.<p></p&gt

The relationship between the severity and mortality of SARS-CoV-2 infection and 25-hydroxyvitamin D concentration — a metaanalysis

Introduction: There is increasing scientific interest in the possible association between hypovitaminosis D and the risk of SARS-CoV-2 infection severity and/or mortality.  Objective: To conduct a metanalysis of the association between 25-hydroxyvitamin D (25(OH)D) concentration and SARS-CoV-2 infection severity or mortality.Material and methods: We searched PubMed, EMBASE, Google scholar and the Cochrane Database of Systematic Reviews for studies published between December 2019 and December 2020. Effect statistics were pooled using random effects models. The quality of included studies was assessed with the Newcastle–Ottawa Scale (NOS). Targeted outcomes: mortality and severity proportions in COVID-19 patients with 25(OH)D deficiency, defined as serum 25(OH)D < 50 nmol/L.  Results: In the 23 studies included (n = 2692), the mean age was 60.8 (SD ± 15.9) years and 53.8% were men. Results suggested that vitamin 25(OH)D deficiency was associated with increased risk of severe SARS-CoV-2 disease (RR 2.00; 95% CI 1.47–2.71, 17 studies) and mortality (RR 2.45; 95% CI 1.24–4.84, 13 studies). Only 7/23 studies reported C-reactive protein values, all of which were > 10 mg/L.Conclusions 25(OH)D deficiency seems associated with increased SARS-CoV-2 infection severity and mortality. However, findings do not imply causality, and randomized controlled trials are required, and new studies should be designed to determine if decreased 25(OH)D is an epiphenomenon or consequence of the inflammatory process associated with severe forms of SARS-CoV-2. Meanwhile, the concentration of 25(OH)D could be considered as a negative acute phase reactant and a poor prognosis in COVID-19 infection

光干渉断層計血管造影による網膜中心静脈閉塞症に併発する黄斑虚血の評価

京都大学0048新制・課程博士博士(医学)甲第20996号医博第4342号新制||医||1027(附属図書館)京都大学大学院医学研究科医学専攻(主査)教授 鈴木 茂彦, 教授 富樫 かおり, 教授 開 祐司学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDFA

Relationship between serum 25-hydroxyvitamin D concentration and acute inflammatory markers in hospitalized patients with SARS-CoV-2 infection

INTRODUCTION: There is experimental and clinical evidence that the serum concentration of 25-hydroxyvita­min D [25(OH)D)] may decrease in acute systemic inflammatory responses; in this context, low values may not necessarily indicate a pre-existing deficiency. This may also apply to low 25(OH)D levels found in the context of the systemic inflammatory response caused by SARS-CoV-2 infection. To conduct a systematic review of the relationship between serum 25(OH)D and the concentrations of C-re­active protein (CRP), interleukin 6 (IL-6) and tumour necrosis factor a (TNF-a) in acutely hospitalized patients with SARS-CoV-2 infection.   MATERIAL AND METHODS: We searched PubMed, EMBASE, Google Scholar and the Cochrane Database of Systematic Reviews for studies published between January 2020 and February 2021. In each study, the au­thors compared levels of inflammatory markers between patients reported as having low levels of 25(OH) D and those above the study cut-off. RESULTS: 18 studies were included (n = 3482, mean age 63.5 ± 9.3 years, 56.9% men). The cut-off for the definition of low 25(OH)D varied across studies. In all studies, mean values for inflammatory markers were higher in the low 25(OH)D groups. These differences were statistically significant (p < 0.05) in 6/15 studies with CRP, 4/8 with IL-6 and 0/1 with TNF-a.   CONCLUSIONS: Markers of acute systemic inflammatory response were elevated in patients with SARS-CoV-2 infection and low concentrations of 25(OH)D. Therefore, the vitamin D status in those patients should be interpreted with caution, and studies should be designed to assess whether hypovitaminosis D could be an epiphenomenon

Association between low serum vitamin D and increased mortality and severity due to COVID-19: reverse causality?

We are very close to completing two years since the start of the COVID-19 pandemic. Even though vaccines have been developed and applied to more than 4 billion people in the world, SARS-CoV-2 continues to be a challenge for humanity. Therefore, it is important to study modifiable risk factors that may increase the severity of COVID-19, and one of the most discussed has been vitamin D. Currently, there is some evidence of association between low serum 25-hydroxyvitamin D [25(OH)D3] and increased mortality and severity due to SARS-CoV-2 infection. Before the pandemic, experimental evidence in animal and human studies had reported that an acute inflammatory process can cause a secondary decrease in 25(OH)D3. COVID-19 can be associated with a severe inflammatory process with an elevation of inflammatory markers; in this light, the reported association between low 25(OH)D3 and COVID-19 severity and/or mortality may be an epiphenomenon of the inflammatory process induced by SARS-CoV-2 and be an example of reverse causality

Untersuchungen von Zugriffen auf den Arbeitsspeicher in Vektorrechnersystemen

TIB: RA 831 (1994)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman