Mass loss Dotaz Zobrazit nápovědu
In sample preparation of biological samples for electron microscopy, many types of embedding media are widely used. Unfortunately, none of them is perfectly resistant to beam induced damage. The article is focused on mass loss measuring of pure epoxy resin EMbed 812 that replaced Epon - the most widely used embedding resin for biological electron microscopy, in a form of ultrathin sections with thicknesses ranging from 30 to 100 nm. The STEM imaging was performed in a quantitative way which allowed us to estimate the mass loss directly up to the total dose of 3000 e-/nm2. For data acquisition we used SEM equipped with a commercial STEM detector working at a relatively low acceleration voltage of 30 kV. In this study we estimated the influence of various factors which can affect the endurance of the epoxy resin EMbed 812 ultrathin sections under an electron beam, such as the sample aging, differences between storing the samples in forms of ultrathin sections and whole blocks, ultrathin sections thicknesses, temperature of the sample, probe current, and one or two-sided carbon coating of ultrathin sections. The aim of this work is to investigate beam induced mass loss at electron energies of SEM and find out how to reduce the mass loss.
- Klíčová slova
- EMbed 812 resin, Epon resin, Epoxy resin, Mass loss, Scanning electron microscopy, Scanning transmission electron microscopy,
- MeSH
- elektrony MeSH
- epoxidové pryskyřice chemie MeSH
- mikroskopie elektronová rastrovací transmisní metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- EPON MeSH Prohlížeč
- epoxidové pryskyřice MeSH
The breakdown of plant material fuels soil functioning and biodiversity. Currently, process understanding of global decomposition patterns and the drivers of such patterns are hampered by the lack of coherent large-scale datasets. We buried 36,000 individual litterbags (tea bags) worldwide and found an overall negative correlation between initial mass-loss rates and stabilization factors of plant-derived carbon, using the Tea Bag Index (TBI). The stabilization factor quantifies the degree to which easy-to-degrade components accumulate during early-stage decomposition (e.g. by environmental limitations). However, agriculture and an interaction between moisture and temperature led to a decoupling between initial mass-loss rates and stabilization, notably in colder locations. Using TBI improved mass-loss estimates of natural litter compared to models that ignored stabilization. Ignoring the transformation of dead plant material to more recalcitrant substances during early-stage decomposition, and the environmental control of this transformation, could overestimate carbon losses during early decomposition in carbon cycle models.
- Klíčová slova
- citizen science, environmental drivers, global change, litter decomposition, mass loss, soil organic matter formation, stabilization, tea bag index,
- MeSH
- koloběh uhlíku MeSH
- listy rostlin * MeSH
- uhlík metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- uhlík MeSH
<b>Aim:</b> The aim was to compare hearing loss between men and women over 65 in pure tone audiometry and to evaluate the sensitivity of the abbreviated version of the Hearing Handicap Inventory (HHIE-S). This questionnaire highlights hearing handicaps in understanding speech. </br></br><b> Materials and Methods:</b> The data was collected in the years 2011-2015 from respondents above 18 years of age using a standar-dized HHIE-S questionnaire and specialized tests. The cohort was divided into groups based on the severity of hearing loss in the better ear according to the World Health Organization (WHO) as measured by tone threshold audiometry at 500 Hertz (Hz), 1000 Hz, 2000 Hz and 4000 Hz. </br></br> <b> Results:</b> Of the 7070 people (61.8% female and 38.2% male), 68.93% had hearing impairment. Most people had a slight he-aring loss. Based on HHIE-S, 56.94% reported impaired hearing. A statistically significant difference was found between the genders, but according to HHIE-S, females with impaired hearing were not statistically significantly more numerous than males. The diagnostic sensitivity of the HHIE-S was assessed in particular by its sensitivity (75.43%) and specificity (82.53%). The probability that a person has a hearing impairment when the HHIE-S test is positive is 90.21%. </br></br> <b> Conclusions:</b> The HHIE-S is fast, inexpensive and short, and can be included as a screening test for hearing impairment in ca-ring for the elderly. Even a minor hearing impairment can be a significant handicap in elderly patients by restricting not only social interactions but also weakening mental functioning.
- Klíčová slova
- Hearing Handicap Inventory, age-related hearing loss, hearing impairment, presbycusis, vulnerable elderly,
- MeSH
- audiometrie čistými tóny MeSH
- hluchota * MeSH
- lidé MeSH
- nedoslýchavost * diagnóza MeSH
- plošný screening MeSH
- průzkumy a dotazníky MeSH
- senioři MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
OBJECTIVE: Loss of muscle mass in critically ill patients is associated with serious consequences, such as prolonged mechanical ventilation, intensive care unit confinement, and higher mortality. Thus, monitoring muscle mass, and especially its decline, should provide a useful indicator of morbidity and mortality. Performing evaluations according only to body mass index is imperfect, therefore the aim of this article was to evaluate appropriate methods for muscle mass loss determination in ICU patients. METHODS: For this review, the literature searches were conducted through Embase and Medline, PubMed and Google Scholar databases up to February 2018 for the following Medical Subject Headings terms muscle atrophy, protein catabolism, ICU-aquaired weakness, muscle muss loss, myolysis, critical illness, stress metabolism, computed tomography, magnetic resonance imaging, dual-energy X-ray absorptiometry, neutron activation analysis, anthropometric examination, determination of endogenous metabolites of the skeletal muscles, bioimpedance spectroscopy, ultrasound. RESULT: It appears that ultrasound, which is widely available in hospitals, is the most advantageous method. Muscle ultrasound is non-invasive, relatively inexpensive, and is a bedside method that is free of ionizing radiation. Furthermore, muscle ultrasound also seems to be valid in patients with severe fluid retention, which is a typical complication with other conventional methods. CONCLUSION: Early detection of critical illness neuromyo-pathy could be beneficial for improving the standards of intensive care, and thus reducing the risk of mortality in these patients.
- MeSH
- index tělesné hmotnosti * MeSH
- kritický stav mortalita MeSH
- lidé MeSH
- míra přežití MeSH
- morbidita MeSH
- prognóza MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
AIM: To assess nutritional status and muscle mass loss in patients with chronic obstructice pulmonary disease (COPD) from the Czech National Database of COPD and to evaluate the association of nutritional parameters with COPD phenotype, lung function, COPD-related symptoms and long-term survival. METHODS: A total of 343 patients with known body composition parameters - body mass Index (BMI), fat-free mass index (FFMI) and mid-art muscle circumference (MAMC) - were included in the analysis. Descriptive statistical methods were used to assess differences between groups, and overall survival was assessed using the Kaplan-Meier method after 9 years of follow-up. RESULTS: Nutritional imbalances were common in patients with COPD. Underweight and muscle mass loss were associated with emphysematous and pulmonary cachexia phenotypes, worse lung function, more symptoms and exacerbations, osteoporosis and depression. Overweight and obesity were associated with a chronic bronchitis phenotype and cardiovascular and metabolic comorbidities. Obese patients had higher forced exspiratory volume in 1 second (FEV1) and diffusing capacity of the lung for carbon monoxid (DLCO), but lower forced exspiratory capacity (FVC). Malnutrition increased the risk of death. Cachexia and underweight reduced median survival from 72.0 to 43.5 (P=0.049) and 39.8 (P=0.010) months, respectively, compared to normal nutrition. Muscle mass loss by MAMC of ≥20% was the strongest predictor of mortality, increasing the risk of death by 5.5-fold compared to patients with normal muscle mass (P<0.001). Patients with overweight and obesity had a 40% (P=0.026) and 30% lower risk of death, respectively, compared to patients with normal nutrition. CONCLUSIONS: Patients with COPD often have nutritional imbalances. That is an important determinant of clinical characteristics and outcomes in patients with COPD. Further research is needed to better understand these differences.
- Klíčová slova
- COPD phenotype, body mass index, chronic obstructive pulmonary disease, comorbidities, fat-free mass index, mid-arm muscle circumference, muscle mass loss, nutrition, survival,
- Publikační typ
- časopisecké články MeSH
Ongoing climate change results in increasing temperatures throughout the seasons. The effects of climate change on insect performance are less studied during the winter season than during the growing season. Here, we investigated the effects of various winter temperature regimes (warm, normal and cold) on the winter performance of the invasive ladybird Harmonia axyridis (Coleoptera: Coccinellidae). Winter survival, body mass loss and post-winter starvation resistance were measured for a laboratory-reared population as well as three populations collected from the field prior to overwintering. The warm winter regime increased the survival rate and body mass loss and reduced post-winter starvation resistance compared to those of the ladybirds in the cold winter regime. The effects of the temperature regime were qualitatively similar for the laboratory-reared and field-collected beetles; however, there were significant quantitative differences in all measured overwintering parameters between the laboratory-reared and field-collected populations. The winter survival of the laboratory-reared beetles was much lower than that of the field-collected beetles. The laboratory-reared beetles also lost a larger proportion of their body mass and had reduced post-winter starvation resistance. Winter survival was similar between the females and males, but compared to the males, the females lost a smaller proportion of their body mass and had better post-winter starvation resistance. The pre-overwintering body mass positively affected winter survival and post-winter starvation resistance in both the laboratory-reared and field-collected ladybirds. The significant differences between the laboratory-reared and field-collected individuals indicate that quantitative conclusions derived from studies investigating solely laboratory-reared individuals cannot be directly extrapolated to field situations.
- MeSH
- aklimatizace MeSH
- brouci růst a vývoj MeSH
- hladovění * MeSH
- index tělesné hmotnosti * MeSH
- nízká teplota * MeSH
- populační dynamika * MeSH
- roční období * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Blood loss during major abdominal surgery is an essential parameter in the evaluation of strategies aimed at reducing perioperative bleeding. However, blood loss quantification remains unreliable and inaccurate. The aim of this study was to compare several methods of blood loss quantification-visual estimation by surgeon and anesthesiologist, the gravimetric method, the calculation method with spectrophotometric measurement. The spectrophotometric measurement is considered as the most accurate method. METHODS: The study was designed as a prospective observational cohort single-center study. We analyzed 61 patients who underwent elective liver or pancreatic resection. The anesthesiologists' and surgeons' estimate of blood loss was based on a visual assessment. The gravimetric method was based on weighing the suction canister and surgical drapes before and after use. The basis of calculation method was anthropometric and hematological parameters, we used López-Picado's formula. The spectrophotometric method was based on the spectrophotometric determination of hemoglobin mass in the lost blood. We compared the methods using paired t-test, non-parametric Wilcoxon test and Bland-Altman analysis. RESULTS: Visual estimation by surgeons and anesthesiologists, gravimetric measurement, and calculation method were significantly different from spectrophotometric measurement at the significance level α = 0.05. All methods overestimated blood loss which was measured by spectrophotometric method. The estimate by surgeons was the closest to the spectrophotometric measurement, difference 68.7 ml (95% confidence interval [CI]: -129.3--8.2). CONCLUSIONS: We conclude that the estimate of blood loss by surgeons and anesthesiologists, as well as gravimetric method and calculation method are all significantly inaccurate in real surgical setting. We did not confirm the commonly accepted assumption that surgeons underestimate the blood loss. TRIAL REGISTRATION: The study was registered under the title " Blood Loss Quantification During Major Abdominal Surgery" at ClinicalTrials.gov with the registration number NCT05316649. Date of the first registration was 20/3/2022.
- Klíčová slova
- Estimated blood loss, Liver resection, Major abdominal surgery, Pancreaticoduodenectomy, Spectrophotometric measurement,
- MeSH
- břicho chirurgie MeSH
- chirurgové * MeSH
- krvácení při operaci MeSH
- lidé MeSH
- poporodní krvácení * MeSH
- prospektivní studie MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- pozorovací studie MeSH
CONTEXT: Adipose tissue (AT) transcriptome studies provide holistic pictures of adaptation to weight and related bioclinical settings changes. OBJECTIVE: To implement AT gene expression profiling and investigate the link between changes in bioclinical parameters and AT gene expression during 3 steps of a 2-phase dietary intervention (DI). METHODS: AT transcriptome profiling was obtained from sequencing 1051 samples, corresponding to 556 distinct individuals enrolled in a weight loss intervention (8-week low-calorie diet (LCD) at 800 kcal/day) followed with a 6-month ad libitum randomized DI. Transcriptome profiles obtained with QuantSeq sequencing were benchmarked against Illumina RNAseq. Reverse transcription quantitative polymerase chain reaction was used to further confirm associations. Cell specificity was assessed using freshly isolated cells and THP-1 cell line. RESULTS: During LCD, 5 modules were found, of which 3 included at least 1 bioclinical variable. Change in body mass index (BMI) connected with changes in mRNA level of genes with inflammatory response signature. In this module, change in BMI was negatively associated with changes in expression of genes encoding secreted protein (GDF15, CCL3, and SPP1). Through all phases of the DI, change in GDF15 was connected to changes in SPP1, CCL3, LIPA and CD68. Further characterization showed that these genes were specific to macrophages (with LIPA, CD68 and GDF15 expressed in anti-inflammatory macrophages) and GDF15 also expressed in preadipocytes. CONCLUSION: Network analyses identified a novel AT feature with GDF15 upregulated with calorie restriction induced weight loss, concomitantly to macrophage markers. In AT, GDF15 was expressed in preadipocytes and macrophages where it was a hallmark of anti-inflammatory cells.
- Klíčová slova
- Adipocyte, inflammation, low calorie diet, macrophage, network analyses, weight loss,
- MeSH
- biologické markery metabolismus MeSH
- dospělí MeSH
- genové regulační sítě * MeSH
- hmotnostní úbytek * MeSH
- index tělesné hmotnosti MeSH
- lidé MeSH
- následné studie MeSH
- obezita metabolismus patologie MeSH
- prognóza MeSH
- redukční dieta * MeSH
- růstový diferenciační faktor 15 genetika metabolismus MeSH
- transkriptom * MeSH
- tuková tkáň metabolismus patologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- multicentrická studie MeSH
- práce podpořená grantem MeSH
- randomizované kontrolované studie MeSH
- Názvy látek
- biologické markery MeSH
- GDF15 protein, human MeSH Prohlížeč
- růstový diferenciační faktor 15 MeSH
International journal of obesity and related metabolic disorders | Int J Obes Relat Metab Disord
Zdroj
OBJECTIVE: To assess the genetic contribution to determinants of therapeutic weight loss in obese female identical twins. DESIGN: Subjects were studied for 40 days on an inpatient unit in three phases: 7 baseline days; 28 days of weight reduction by a very low calorie diet (1.6 MJ per day); and 5 days after weight reduction. SUBJECTS: Fourteen pairs of premenopausal obese female identical twins (age: 39.0+/-1.7 y; body weight (BW): 93.9+/-21.2 kg; body mass index (BMI): 34.2+/-7.8 kg/m2). MEASUREMENTS: : Body composition by hydrodensitometry and resting metabolic rate by indirect calorimetry were assessed before and after weight loss. RESULTS: : There was great variability among pairs in loss of weight (5.9-12.4 kg) and body fat (3.1-12.4 kg). By contrast, the intraclass correlation (ICC) within twin pairs was 0.85, P<0.001 for weight and 0.88, P<0.001 for body fat. A measure of metabolic efficiency, calculated as the difference between 'estimated' and 'measured' energy deficit showed high intrapair correlation (ICC=0.77; P<0.001). CONCLUSIONS: The high correlation in metabolic efficiency within twin pairs in response to therapeutic weight loss suggests a strong genetic contribution.
- MeSH
- bazální metabolismus genetika MeSH
- dospělí MeSH
- energetický metabolismus genetika MeSH
- hmotnostní úbytek genetika MeSH
- lidé MeSH
- nepřímá kalorimetrie MeSH
- obezita dietoterapie genetika metabolismus MeSH
- redukční dieta * MeSH
- složení těla genetika MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, P.H.S. MeSH
- studie na dvojčatech MeSH
A mass spectrometric (MS) comparative study of dextran samples using two different ionization techniques (matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI)) in both positive- and negative-ion modes is reported. The experiments were carried out with two polydisperse dextrans (1000 and 8800 Da) and isomaltotriose. In the positive-ion mode, the expected alkali metal ion adducts of dextrans were observed in both techniques. In contrast, the expected preferential formation of deprotonated molecules [M - H](-) was not confirmed in negative mode MALDI time-of-flight (TOF) MS, where the series of ions [M(x)- H +42](-) or [M(x+1)- H - 120](-), coming either from some addition or fragmentation, were observed. In both ionization techniques, these ions formed the main distributions of dextrans in the negative-ion mode. It seems that the negative molecular ions formed from the alpha1 --> 6 linkage of polyglucose oligomers easily decompose, and the product ions [M - H - 120](-) markedly dominate. The fragmentation experiments and especially the investigation of the fundamental role of the nozzle-skimmer potential in ESI-MS supported our explanation of the observed behavior because its higher values caused higher fragmentation. The experiments with isomaltotriose excluded any addition of 42 Da during the MS procedures, which is not distinguishable from the loss of 120 Da in the case of polydisperse dextrans. MALDI-TOFMS was found to be more sensitive for the detection of higher oligosaccharides and ESI-MS more useful for structural studies.
- MeSH
- dextrany chemie izolace a purifikace MeSH
- hmotnostní spektrometrie s elektrosprejovou ionizací metody MeSH
- hmotnostní spektrometrie metody MeSH
- ionty MeSH
- oligosacharidy chemie MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- dextrany MeSH
- ionty MeSH
- oligosacharidy MeSH