Raman Spectroscopy as a Promising Tool for Noninvasive Point-of-Care Glucose Monitoring

Self-monitoring of glucose is important for managing diabetes. Noninvasive glucose monitors are not yet available, but patients would benefit highly from such a device. We present results that may lead to a novel, point-of-care noninvasive system to measure blood glucose based on Raman spectroscopy. A hospitalized cohort of 111 subjects was measured using a custom-made Raman spectrometer system. Blood glucose reference samples were used to correlate Raman data to glucose levels, using advanced preprocessing and analysis algorithms. A correlation coefficient (R²) of .83 was found correlating independent Raman-based predictions on reference blood glucose for the full cohort. Stratification of the cohort in gender-specific groups raised correlation levels to .88 (females) and .94 (males). Glucose could be measured noninvasively with average errors as low as 0.9 mM. We conclude that this novel system shows promising results for the advance of noninvasive, point-of-care glucose monitoring.     

Plant Material as a Novel Tool in Designing and Formulating Modern Biostimulants—Analysis of Botanical Extract from Linum usitatissimum L.

Nowadays, researchers are looking into next-generation biostimulants that can be designed as a dedicated agronomic tool based on plant materials. The aim of the present study was to develop a novel biostimulating product, based on plant material in the form of linseed aqueous extracts. The scope of the research included the physicochemical characterization of the product and identification of its biostimulating potential. The study has confirmed that the plant biostimulant derived from L. usitatissimum can be used as a viable agronomic tool for growing soybean. The designed and produced biostimulant is rich in bioactive compounds, including amino acids, free fatty acids, carbohydrates, and micro- and macroelements. The tested biostimulant showed significantly lower values of surface tension in relation to water and a commercial biostimulant. The soybean crops responded to the application of the preparation by improvements in agronomic and morphological levels. The linseed macerates were effective in terms of soybean yields and profitability. Our findings serve as preliminary evidence for the viability of designing and developing novel biostimulants derived from plant materials. This comprehensive approach to designing and formulating novel bioproducts necessitates more extensive and targeted research to fully explain the mechanisms behind the improvements observed in the soybean cultivation.     

Index of Microcirculatory Resistance as a Tool to Characterize Microvascular Obstruction and to Predict Infarct Size Regression in Patients With STEMI Undergoing Primary PCI

ObjectivesThis study aimed to compare the value of the index of microcirculatory resistance (IMR) and microvascular obstruction (MVO) measured by cardiac magnetic resonance (CMR) in patients treated for and recovering from ST-segment elevation myocardial infarction.BackgroundIMR can identify patients with microvascular dysfunction acutely after primary percutaneous coronary intervention (pPCI), and a threshold of >40 has been shown to be associated with an adverse clinical outcome. Similarly, MVO is recognized as an adverse feature in patients with ST-segment elevation myocardial infarction. Even though both IMR and MVO reflect coronary microvascular status, the interaction between these 2 parameters is uncertain.MethodsA total of 110 patients treated with pPCI were included, and IMR was measured immediately at completion of pPCI. Infarct size (IS) as a percentage of left ventricular mass was quantified at 48 h (38.4 ± 12.0 h) and 6 months (194.0 ± 20.0 days) using CMR. MVO was identified and quantified at 48 h by CMR.ResultsOverall, a discordance between IMR and MVO was observed in 36.7% of cases, with 31 patients having MVO and IMR ≤40. Compared with patients with MVO and IMR ≤40, patients with both MVO and IMR >40 had an 11.9-fold increased risk of final IS >25% at 6 months (p = 0.001). Patients with MVO and IMR ≤40 had a significantly smaller IS at 6 months (p = 0.001), with significant regression in IS over time (34.4% [interquartile range (IQR): 27.3% to 41.0%] vs. 22.3% [IQR: 16.0% to 30.0%]; p = 0.001).ConclusionsDiscordant prognostic information was obtained from IMR and MVO in nearly one-third of cases; however, IMR can be helpful in grading the degree and severity of MVO.     

Evaluation of the Potential of Modified Calcium Carbonate as a Carrier for Unsaturated Fatty Acids in Oxygen Scavenging Applications

Modified calcium carbonates (MCC) are inorganic mineral-based particles with a large surface area, which is enlarged by their porous internal structure consisting of hydroxyapatite and calcium carbonate crystal structures. Such materials have high potential for use as carriers for active substances such as oxygen scavenging agents. Oxygen scavengers are applied to packaging to preserve the quality of oxygen-sensitive products. This study investigated the potential of MCC as a novel carrier system for unsaturated fatty acids (UFAs), with the intention of developing an oxygen scavenger. Linoleic acid (LA) and oleic acid (OA) were loaded on MCC powder, and the loaded MCC particles were characterized and studied for their oxygen scavenging activity. For both LA and OA, amounts of 20 wt% loading on MCC were found to provide optimal surface area/volume ratios. Spreading UFAs over large surface areas of 31.6 and 49 m² g⁻¹ MCC enabled oxygen exposure and action on a multitude of molecular sites, resulting in oxygen scavenging rates of 12.2 ± 0.6 and 1.7 ± 0.2 mL O₂ d⁻¹ g⁻¹, and maximum oxygen absorption capacities of >195.6 ± 13.5 and >165.0 ± 2.0 mL g⁻¹, respectively. Oxygen scavenging activity decreased with increasing humidity (37–100% RH) and increased with rising temperatures (5–30 °C). Overall, highly porous MCC was concluded to be a suitable UFA carrier for oxygen scavenging applications in food packaging.     

The Composites of PCL and Tetranuclear Titanium(IV)–Oxo Complex with Acetylsalicylate Ligands—Assessment of Their Biocompatibility and Antimicrobial Activity with the Correlation to EPR Spectroscopy

In our research, we have focused on the biological studies on composite materials produced by the dispersion of titanium(IV)–oxo complex (TOC) with acetylsalicylate ligands in a poly(ε-caprolactone) (PCL) matrix, which is a biodegradable thermoplastic polymer increasingly used in the production of medical devices. Using PCL as a matrix for the biologically active compounds, such as antimicrobial agents, antibiotics or other active medical substances, from which these individuals can be gradually released is fully understable. Composites of PCL + nTOC (n = 10, 15 and 20 wt.%) have been produced and, in such a form, the biological properties of TOCs have been estimated. Direct and indirect cytotoxicity studies have been performed in vitro on L929 and human umbilical vein endothelial cells (HUVEC) cell lines. The antibacterial and antifungal activity of the PCL + TOC samples have been assessed against two Staphylococcus aureus (ATCC 6538 and ATCC 25923) reference strains, two Escherichia coli (ATCC 8739 and ATCC 25922) reference strains and yeast of Candida albicans ATCC 10231. Obtained results have been correlated with electron paramagnetic resonance (EPR) spectroscopy data. We could conclude that photoexcitation by visible light of the surface of PCL + nTOC composite foils lead to the formation of different paramagnetic species, mainly O⁻, which slowly disappears over time; however, their destructive effect on bacteria and cells has been proven.     

A Rheological Analysis of Biomaterial Behaviour as a Tool to Detect the Dilution of Heather Honey

Heather honey is a valuable and rheologically special type of honey. Its above-average selling price may motivate its intentional violation with a mixture of honey from another botanical origin, the price of which is lower on the market. This work deals with the rheological properties of such devalued heather honey in order to determine the changes in the individual rheological parameters depending on the degree of dilution of the heather honey. For this purpose, a differently diluted heather honey sample series was created and the following rheological parameters were determined: hysteresis area, n-value, yield stress (τ₀), parameter B (Weltman model), parameter ϕ, or parameter C (model describing the logarithmic dependence of the complex viscosity on the angular frequency). Part of the work was research into whether the set parameters can be used as comparative parameters. It was found that the hysteresis area does not appear to be a suitable relative comparison parameter due to the high variability. The parameters that appear to be suitable are the relative parameters n-value and the parameter ϕ, which showed the greatest stability. The change in the determined rheological parameters is, depending on the degree of dilution, non-linear with a step change between the samples containing 40% (w/w) and 60% (w/w) of a heather honey.     

FEM Analysis as a Tool to Study the Behavior of Methacrylate Adhesive in a Full-Scale Steel-Steel Shear Joint

The use of adhesive to joint structural elements, despite many advantages of this technology, is not a method commonly used in engineering practice, especially in construction. This is mainly due to the poor recognition of the behavior, both in terms of testing and analysis, of joints made on a scale similar to the actual elements of building structures. Therefore, this paper presents the results of model tests and then numerical analyses of adhesively bonded joints made of high-strength steel elements in a full-scale (double-lap joint). In order to properly model the adhesive connection, material tests of the methacrylate adhesive were performed in the field of tensile, shear (in two versions: single lap joint test and thick adherent shear test) and bond properties. Comparison of the results of the model and numerical tests showed very good agreement in terms of the measurable values, which makes it possible to consider the results obtained in the adhesive layer as reliable (not directly measurable in model tests). In particular, the distribution of stresses inside the adhesive layer, the range of plastic zones and areas of loss of adhesion are presented and discussed. The results indicate the possibility of a reliable representation of the behavior of adhesively bonded joints of high-strength steel, thus providing a tool for the analysis of semirigid adhesive in large-size joints.     

Nucleobases bind to and stabilize aggregates of a prebiotic amphiphile,providing a viable mechanism for the emergence of protocells

Primordial cells presumably combined RNAs, which functioned as catalysts and carriers of genetic information, with an encapsulating membrane of aggregated amphiphilic molecules. Major questions regarding this hypothesis include how the four bases and the sugar in RNA were selected from a mixture of prebiotic compounds and colocalized with such membranes, and how the membranes were stabilized against flocculation in salt water. To address these questions, we explored the possibility that aggregates of decanoic acid, a prebiotic amphiphile, interact with the bases and sugar found in RNA. We found that these bases, as well as some but not all related bases, bind to decanoic acid aggregates. Moreover, both the bases and ribose inhibit flocculation of decanoic acid by salt. The extent of inhibition by the bases correlates with the extent of their binding, and ribose inhibits to a greater extent than three similar sugars. Finally, the stabilizing effects of a base and ribose are additive. Thus, aggregates of a prebiotic amphiphile bind certain heterocyclic bases and sugars, including those found in RNA, and this binding stabilizes the aggregates against salt. These mutually reinforcing mechanisms might have driven the emergence of protocells.     

From the Cover: Species distributions in response to individual soil nutrients and seasonal drought across a community of tropical trees

Tropical forest vegetation is shaped by climate and by soil, but understanding how the distributions of individual tree species respond to specific resources has been hindered by high diversity and consequent rarity. To study species over an entire community, we surveyed trees and measured soil chemistry across climatic and geological gradients in central Panama and then used a unique hierarchical model of species occurrence as a function of rainfall and soil chemistry to circumvent analytical difficulties posed by rare species. The results are a quantitative assessment of the responses of 550 tree species to eight environmental factors, providing a measure of the importance of each factor across the entire tree community. Dry-season intensity and soil phosphorus were the strongest predictors, each affecting the distribution of more than half of the species. Although we anticipated clear-cut responses to dry-season intensity, the finding that many species have pronounced associations with either high or low phosphorus reveals a previously unquantified role for this nutrient in limiting tropical tree distributions. The results provide the data necessary for understanding distributional limits of tree species and predicting future changes in forest composition.     

Echocardiography as a Simple Initial Tool to Assess Right Ventricular Dimensions in Patients with Repaired Tetralogy of Fallot before Undergoing Pulmonary Valve Replacement: Comparison with Cardiovascular Magnetic Resonance Imaging

Objective: Accurate assessment of the right ventricle (RV) is essential in patients with repaired tetralogy of Fallot (TOF). We proposed a simple echocardiographic method to assess the RV dimensions and evaluated the relationship between linear echocardiographic measures of the RV and RV volumes obtained by cardiovascular magnetic resonance imaging (CMR). Methods: A total of 45 patients (27.4 ± 11.2 years; 40% male) with repaired TOF underwent CMR and echocardiography. Using echocardiography, RV dimensions were assessed from the parasternal short‐axis view using the longest RV internal diameter perpendicular to the mid‐interventricular septum. Significant RV dilatation was defined as an RV end‐diastolic volume index >160 mL/m² on CMR. Results: There were significant correlations between RV dimensions determined by echocardiography and the pulmonary regurgitation fraction, RV size, and function determined by CMR. The cutoff values of echocardiographic RV outflow tract (RVOT), end‐systolic and end‐diastolic dimension indices, and the combination of RVOT and end‐diastolic dimension indices to determine significant RV dilatation were 19.0, 19.4, 24.5, and 45.2 mm/m², respectively. The positive and negative predictive values for significant RV dilatation were 89.7% and 68.8% with RVOT diameter index ≥19.0 mm/m², 85.0% and 52.4% with RV end‐systolic dimension index ≥19.4 mm/m², 87.5% and 64.7% with RV end‐diastolic dimension index ≥24.5 mm/m², and 92.3% and 80.0% with the combination of RVOT and end‐diastolic dimension indices ≥45.2 mm/m², respectively. Conclusion: Echocardiography can be used to assess RV size in patients with repaired TOF with acceptable correlations with CMR as the reference standard.     

The intramyocardial fate of [1-C] palmitate, iodopalmitate and iodophenylpentadecanoate in isolated rat hearts. A contribution to the choice of an iodinated fatty acid as a tracer of myocardial metabolism

Labeled iodinated fatty acids (FAs) have been proposed to explore myocardial metabolism by external detection in man. We have chosen a 16-carbon FA, iodinated in ω position, whereas other authors use an iodophenylated FA. To explore the influence of the presence of an iodine or of an iodophenyl radical on the metabolism of the FA, we have compared, in isolated rat hearts perfused in a recirculating system, the intramyocardial fate of palmitate (PA), iodopalmitate (IPA), and iodophenylpentadecanoate (IPPA), the 3 of them being labeled with C14 in position 1. The addition of the iodine atom brings about a hindrance to the esterification of the FA into triglycerides, but not modification of the myocardial uptake and of the CO₂ produced. The addition of the iodophenyl radical impairs both the FA storage and its oxidation, leading to a very high level of free FA. The phospholipid distribution is also modified. Apart from their myocardial use in the isolated rat heart, the 3 FAs were assayed in vitro as a substrate for acylCoA-synthase. As IPA more closely mimics native FA metabolism, it is therefore more suitable than IPPA as a tracer of myocardial metabolism.     

Clinical evaluation of somatostatin as a potential adjunct to insulin in the management of diabetes mellitus

Summary To determine whether somatostatin, an inhibitor of glucagon and growth hormone secretion, might be useful as an adjunct to insulin in the management of diabetic hyperglycaemia, seven insulinrequiring diabetic men were given somatostatin (100 g/h, IV) continuously for 3 days after their diabetes had been treated intensively by diet and insulin on a metabolic ward. During infusion of somatostatin and despite reduction in average insulin dose exceeding 50%, there was improvement in diabetic control as assessed by postprandial hyperglycaemia, 24-h glycosuria and the average daily serum glucose level and its fluctuation; when somatostatin was discontinued, but insulin doses held constant, diabetic control rapidly worsened. No adverse effects were observed. These results indicate that somatostatin plus insulin can be a more effective regimen than insulin alone in controlling diabetic hyperglycaemia. A longer acting and more selective somatostatin preparation may prove useful as an adjunct to insulin in the management of diabetes.     

Fluorescence induced in platelet aggregates as a guide to luminal contours in the presence of platelet aggregation

After intravenous injection of sodium fluorescein, appropriately filtered uv light will cause platelets to aggregate in the microcirculation. These aggregates brightly fluoresce. When aggregates build up and encroach on the vessel lumen they produce an irregular contour. When such vessels are observed by ordinary in vivo microscopy, the adherent aggregates (“white bodies”) may be difficult to distinguish from the vessel wall, which may itself be difficult to define. The appearance of the red cell column then commonly becomes the basis for determining vessel contour or diameter and an erroneous impression of irregular vasoconstriction may be obtained. The bright fluorescence of the platelet aggregates under uv illumination readily corrects this impression. Aggregates induced by other means may also fluoresce under uv light if fluorescein is injected following aggregation. However, production of aggregates by fluorescein and by uv light is a method which uniquely permits simultaneous production of aggregation and precise evaluation of apparent vasoconstriction or luminal narrowing.     

Use of a laboratory only score system to define trajectories and outcomes of older people admitted to the acute hospital as medical emergencies

Aim: Increasing numbers of older people are admitted to hospital as medical emergencies. They are a heterogeneous population with uncertain trajectories and outcomes. Our aim was to retrospectively characterize subgroups of older inpatients based on their acuity trajectories. Methods: This was a single‐center patient series from St James's Hospital Dublin, Ireland (2002–2010). The Medical Admissions Risk System (MARS) score was used to classify a sample of 14 607 patients aged ≥65 years, from admission to end of episode, into four trajectory groups: (i) static high acuity (group 1); (ii) static low acuity (group 2); (iii) inpatient deterioration (group 3); and (iv) inpatient improvement (group 4). K‐means cluster analysis was used for the classification. Results: Group 1 (4.1%): median length of stay (LOS) 7.4 days, 23.6% used intensive care, mortality rate 79.2%; sepsis and renal failure were the dominant features. Group 2 (76.6%): median LOS 8.0 days, 5.2% used intensive care, mortality rate 9.5%; younger age, low comorbidity and diseases of non‐vital organs were predominant. Group 3 (7.6%): median LOS 17.2 days, 17.4% used intensive care, mortality rate 76.1%; high comorbidity and sepsis/respiratory disease featured. Group 4 (11.7%): median LOS 12.1 days, 12.8% used intensive care, mortality rate 22.7%; sepsis and renal/metabolic disease were frequent, and comorbidity levels were intermediate. Conclusions: In older acute medical inpatients, the outcome seemed more driven by specific diagnoses (such as sepsis and renal failure) and comorbidity, than by age. Using the MARS score to retrospectively categorize older inpatients might help to understand their heterogeneity and promote the design of appropriate care pathways. Geriatr Gerontol Int 2013; 13: 405–412 .     

Differences in the responses of the pituitary beta-endorphin and cardiovascular system to ethanol and stress as a function of family history

BACKGROUND: Genetic and environmental factors, such as stress, are important for the initiation and maintenance of heavy drinking, whereas beta-endorphin may be important in controlling alcohol consumption. These studies investigated the response of pituitary beta-endorphin to stress and the effect of alcohol on the stress response in subjects at low (LR) and high (HR) risk of alcoholism, as determined from their family history. METHODS: Twenty LR and 20 HR subjects were exposed to stress 30 min after ingestion of either a placebo or an alcohol drink. Plasma beta-endorphin was measured before and for 4 hr after the drink. Changes in the concentration of plasma beta-endorphin after ingestion of the placebo or alcohol drink alone served as controls to compare the stress-induced changes. Pulse and diastolic and systolic blood pressure were also measured. RESULTS: HR subjects presented higher baseline values of pulse and systolic blood pressure and lower plasma beta-endorphin than LR subjects. Stress induced a small increase in cardiovascular activity, whereas alcohol induced a stronger stimulation. Alcohol before stress did not prevent the stress-induced increase in cardiovascular activity. Stress, but not alcohol, increased the plasma beta-endorphin concentration. LR subjects presented a higher stress-induced increase in plasma beta-endorphin and a faster recovery than HR subjects. Alcohol before stress attenuated the stress-induced increase in plasma beta-endorphin in both LR and HR subjects. This attenuation was stronger in LR subjects. CONCLUSIONS: Thus, there are differences in the response of beta-endorphin to stress and the effect of ethanol on stress responses as a function of a family history of alcoholism.     

Use of diethyldithiocarbamate as a probe to detect stable intermediates during the decomposition of several mutagenic and nonmutagenic N-nitroso compounds

Summary By showing that methyldiethyldithiocarbamate is formed from the reaction of methylnitrosourea and disulfiram, we demonstrated in previous experiments that one of the anticarcinogenic/antimutagenic mechanisms of disulfiram is the scavenging of reactive species. We propose that this reaction may be employed additionally as a model for elucidating the following: (a) possible reactions between alkylating species and nucleophilic sites within the cell, and (b) the existence of stable intermediates during the metabolism of N-nitroso compounds. With structurally related pairs of nitrosoureas (n-propyl/isopropyl; cyclopropyl/allyl; 2-phenylethyl/1-phenylethyl), for which each alkylating group of the first compound can spontaneously rearrange to form the alkylating group of the second isomer, we investigated whether the alkylation proceeds via a monomolecular (sn1) or a bimolecular substitution (sn2). For this, we comparatively determined the relative mutagenic activities of each isomer in Salmonella typhimurium TA 1535, as well as their reactivities towards diethyldithiocarbamate (DDTC) by identifying the reaction products. These studies were aimed at revealing the possible formation of a free carbonium ion in the decomposition of several nitrosoureas in the rat liver supernatant fraction. Our system showed that DDTC reacts by two competing mechanisms: attack at the diazonium ion and at the free carbonium ion.Therefore the striking differences which were observed in the mutagenic potency of cyclopropylnitrosourea and N-nitrosoallylurea as well as of N-nitroso-2-phenylethylurea and N-nitroso-1-phenylethylurea cannot be explained only by the different electrophilic reactivities of the respective intermediates.Dedicated to Professor Dietrich Schmähl on the occasion of this 60th birthday