Supercritical Carbon Dioxide Extraction of Allium ursinum: Impact of Temperature and Pressure on the Extracts Chemical Profile

The aim of this study was to extract Allium ursinum L. for the first time by supercritical carbon dioxide (SC−CO₂) as green sustainable method. The impact of temperature in the range from 40 to 60 °C and pressure between 150 and 400 bar on the quality of the obtained extracts and efficiency of the extraction was investigated. The highest extraction yield (3.43 %) was achieved by applying the extraction conditions of 400 bar and 60 °C. The analysis of the extracts was performed by gas chromatography and mass spectrometry (GC/MS). The most dominant sulfur-containing constituent of the extracts was allyl methyl trisulfide with the highest abundance at 350 bar and 50 °C. In addition, the presence of other pharmacologically potent sulfur compounds was recorded including S-methyl methanethiosulfinate, diallyl trisulfide, S-methyl methylthiosulfonate, and dimethyl trisulfide. Multivariate data analysis tool was utilized to investigate distributions of the identified compounds among the extracts obtained under various extraction conditions and yields. It was determined that the SC−CO₂ extraction can by efficiently used for A. ursinum.     

Finite element method analysis of the tooth movement induced by orthodontic forces

The finite element method is a useful technique for measuring structural stress and for movement analyses. The objective of this investigation was to get a more accurate estimation of tooth movement depending on application point when a tipping orthodontic force is applied. The three-dimensional model of un upper canine, consisting of 4,000 hexahedron elements with 2,367 nodes was obtained. Horizontal, orally directed 1N tipping orthodontic force was applied to the model on five different levels of the tooth crown. The three-dimensional mathematical finite element model is useful in analyzing the tooth movement in response to orthodontic forces. The tipping tooth movement is greater if the force is applied closer to its neck, or more gingivally.     

Mismatch repair in the antimutator Escherichia coli mud

Antimutators are genetic mutants that produce mutations at reduced rates compared to the wild type strain. They are interesting because they may provide insights into the mechanisms by which spontaneous mutations occur. We have investigated a reported antimutator strain of Escherichia coli termed mud for its possible mechanism. The mud strain exhibits a decrease in both spontaneous mutagenesis and mutability with alkylated agents and base analogs. These types of DNA lesions are known to be the substrates for the E. coli methyl-directed mismatch repair encoded by the mutHLSU system. We investigated whether the putative antimutator effect results from the increased expression or activity of the mutHLSU system. To directly measure the mismatch repair capacity of mud cells, we have transfected them with phage lambda heteroduplexes and scored the fraction of mixed (unrepaired) infective centers. This transfection system has been used routinely to assay mismatch repair capacity in E. coli and other organisms. No difference between mud and wild type cells is observed. From the results of the experiments we conclude that the reported antimutator effect of mud does not result from enhanced mismatch repair capacity. This conclusion is consistent with recently published evidence that the mud effect does not represent a real antimutator effect, but is an artifact due to impaired growth of mud cells under certain selective conditions.     

Changes in particulate and dissolved organic matter in nutrient-enriched enclosures from an area influenced by mucilage: the northern Adriatic Sea

This study examined the partitioning of organic matter intoparticulate organic carbon (POC) and dissolved organic carbon(DOC) pools in nutrient-enriched enclosures containing naturalplankton from the Gulf of Trieste (northern Adriatic), an areaaffected by mucilage. The strategy of nutrient additions wasto introduce a pulse of new nutrients in concentrations thatmimic natural inputs and to survey community structure and organicmatter fluxes long enough so that plankton became nutrient-limited.Maximal bacterial biomass attained roughly double the initialvalue, while autotrophic carbon increased by nearly an orderof magnitude. The microflagellate-dominated community releasedmore DOC per unit biomass (5.5 ± 7.2 to 50.6 ±28.0 µg C µg Chl a^-1 day^-1 versus 3.4 ± 3.4to 10.8 ± 4.6 µg C µg Chl a^-1 day^-1 for diatom-dominatedphytoplankton), POC increase was modest (~300 µg C l^-1)and there was little change in DOC. Organic carbon partitioningduring two experiments in which diatoms prevailed was dominatedby POC (>800 µg C l^-1) in the exponential growth phasewith an increasing contribution of particulate carbohydratesthat paralleled gradual nutrient depletion. Transition to thestationary phase and the decay of autotrophic communities wereaccompanied by the net accumulation of a carbohydrate-rich DOC.     

Antioxidant Properties of Selected <Emphasis Type="Italic">Boletus</Emphasis> Mushrooms

Considering the growing interest for mushrooms and the demand search of natural antioxidants sources, the aim of this study was to investigate the antioxidant properties of two edible widely used Boletus species, Boletus edulis, and Boletus auranticus, collected from Istra region in Croatia in late summer 2007. To evaluate the antioxidant properties and content of antioxidant compounds, scavenging capacity on DPPH˙, OH˙, and O₂˙⁻ radicals, reducing power and capacity to inhibit lipid peroxidation has been investigated. It is determined that content of total phenols (41.82 ± 0.08 mg gallic acid equivalent per gram of dry extract) was higher for B. edulis. Using high performance liquid chromatography/diode array detector analysis, the main antioxidant compound, variegatic acid, has been detected and quantified. 1,1-Diphenyl-2-picryl-hydrazyl-hydrate assay was used as a preliminary free radical–scavenging evaluation. By this assay, it has been found that B. edulis dry mushroom extract exhibits 50% of inhibition value at the extract concentration of 0.016 ± 0.0003 mg/ml. The extracts were capable of reducing iron(III) and, thus, are capable of donating electrons. Using electron paramagnetic resonance spin-trapping and spin-probing techniques, activity against relevant reactive species, ˙OH and O₂˙⁻ radical, was analyzed for both mushroom extracts. Both investigated extracts are determined as good inhibitors for ˙OH radical reduction, and both exhibited significant capacity for scavenging O₂˙⁻ radical and for that could help to prevent or meliorate oxidative damage. Only B. edulis extract prevents lipid peroxidation. Investigated mushroom extracts could represent easily accessible natural antioxidant resource.     

The antioxidant properties of polypore mushroom <Emphasis Type="Italic">Daedaleopsis confragosa</Emphasis>

Daedaleopsis confragosa belong to a large and remarkable group of mushrooms called polypores. This type of mushroom could be easily said to be quite unexplored and unused when it comes to its antioxidant properties. Thus, in order to evaluate its antioxidant activity, the investigation had to include the total phenolics and flavonoide content, the content of Selenium, the content of Zinc, the scavenging capacity on DPPH^· and OH^· radicals, reducing power and capacity to remove lipid peroxidation. The investigated mushroom extract contained 54.17 mg GAE/g of total phenols and 48.46 mg CE/g of total flavonoides. Zinc and Selenium were detected and quantified by using inductively coupled plasma mass spectroscopy. The scavenging activity of the radicals was found to exhibit 50% of the inhibition value (IC₅₀ value) at the extract concentration of 0.015±0.007 mg/ml for the investigated D. confragosa extract. By using electron paramagnetic resonant spectroscopy it was found that the investigated extract does not have a significant role in the prevention of lipid peroxidation. It was effective in scavenging on ^·OH radical, RI was 56±2%.     

Status of the DPC4 tumor suppressor gene in sporadic colon adenocarcinoma of Croatian patients: identification of a novel somatic mutation

Loss of heterozygosity (LOH) of loci on chromosome 18q occurs in a majority of colorectal cancers. The DPC4 (Smad4) tumor suppressor gene, located at 18q21.1, may be a predisposing gene for Juvenile Polyposis Syndrome. To investigate alterations of the DPC4 gene in sporadic colon adenocarcinoma, a panel of 60 tumor specimens from Croatian patients was surveyed for evidence of LOH and also for mutations within the entire DPC4 coding region (exons 1-11). Using three pairs of specific primers for the three DPC4 microsatellite repetitive sequences, we investigated the frequency of LOH. The presence of single nucleotide change at restriction sites of specific codons in exons 2, 8, 10, and 11 (which belong to the conserved region of the gene) was examined by RFLP analysis. The investigation was extended to search for any other mutation within the entire coding region of the DPC4 gene by single strand conformation polymorphism (SSCP) analysis. Our results show a high frequency of heterozygosity in 58 of 60 (97%) colon adenocarcinoma samples. LOH at any one of the three flanking markers was observed in 26 (45%) of the 58 informative cases. The loss of one allele of the DPC4 gene was negatively correlated with tumor size; more frequent in smaller tumors (<5 cm) than in larger ones. A mutation was found in exon 11 in only one tumor sample (T18), and the mutation was verified by sequencing. Sequencing demonstrated a novel mutation-a deletion in exon 11 (134-153 del TAGACGAAGTACTTCATACC) of the DPC4 gene in the MH2 domain. These data suggest that inactivation of the DPC4 gene contributes to the genesis of colorectal carcinoma through allelic loss whereas mutation in the coding region of the DPC4 gene is infrequently detected in Croatian patients with A, B or C stages of colorectal cancers.     

Peripheral regional analgesia with femoral catheter versus intravenous patient controlled analgesia after total knee arthroplasty: a prospective randomized study

The aim of this study is to compare the effects of femoral analgesia (FA) with 0.25% levobupivacain and intravenous patient controlled analgesia (PCA) with morphine on postoperative pain assessed by a visual-analog scale (VAS) score and their complications during the first 24 postoperative hours after the a total knee arthroplasty in a prospective randomized study. Secondary outcomes included: morphine use, patient satisfaction, complication of analgesia and duration of hospital stay. We analyzed 71 patients with an ASA score of II or III. The patients were randomized into two groups: group PCA (n = 36) was given the PCA pump, which contained morphine; and group FA (n = 35) was given first a bolus dose, then a continuous infusion 0.25% levobupivacain via a femoral catheter. The assessment of VAS was performed every 2 hours. There were no differences between the PCA and FA groups regarding demographic characteristics, operation duration, ASA score distribution, duration of hospital stay and satisfaction with analgesia (although there were more satisfied patients in the FA group). Significant differences were noted in the quantity of morphine used (higher values were in the PCA group; p < 0.001). More complications were recorded in PCA group (p < 0.001). The VAS score was lower in the FA group (p < 0.001). The highest difference occurred 4 hours after the operation, with the PCA group having significantly higher VAS score values compared to the FA group. Femoral analgesia leads to a stronger pain relief with less side effects, less morphine use and more patient satisfaction than intravenous PCA with morphine.