Implant supported dentures: an estimation of chewing efficiency

doi: 10.1111/j.1741‐2358.2009.00303.x
Implant supported dentures: an estimation of chewing efficiency Background: Treatment of edentulous patients is one of the most demanding tasks the dentist can meet in his everyday practice. Implant based methods help to improve functioning of dentures and life quality of so treated patients. Objectives: The aim of the study was to evaluate the chewing efficiency of patients treated with lower complete implant‐supported overdentures and the simultaneous evaluation of treatment results by patients. Materials and methods: For the investigation were chosen edentulous patients, treated with upper conventional complete dentures and lower complete overdentures supported on two implants. In this group of patients, were conducted investigations of chewing efficiency changes, based on the Optocal test and overdentures functioning evaluation made by patients in the survey. Results: The objective evaluation of the chewing efficiency indicated the decrease of this value in the five years of observations. Lower complete overdentures supported on implants significantly increased the comfort of chewing of edentulous patients. Conclusions: The results of the study let us to assess positively the result of the therapy using titanium implants and lower complete overdentures. The therapy described significantly increases the life comfort of the edentulous patients. Decreasing chewing efficiency indicated by the research result should be compensated with the dentures maintaining or the prostheses exchange after about five years of use.     

Characterization of bone-marrow-derived rat mesenchymal stem cells depending on donor age

It is generally accepted that autologous transfers, as non-immunogenic, constitute the safest approach in cellular transplantations. However, this attitude is often associated with the need for isolation and extracorporeal propagation of cells derived from aged patients. Thus the knowledge about relationship between aging and the properties of MSCs (mesenchymal stem cells) is crucial in developing new clinical strategies. The aim of this study was to perform complex comparison of MSC derived from young and aged individuals, which included phenotype, proliferating rate, osteogenic and adipogenic potential and secretory activity. Evaluated populations were isolated from bone marrow of 3-month-old and 24-month-old rats. There was no significant difference in membrane antigen expression and PDT (population doubling time). Additionally, the adipogenic and osteogenic potential did not vary between studied populations. The reaction of MSCs to either mitogen [bFGF (basic fibroblas t growth factor)] or oxidative stress (H2O2) in vitro displayed a very similar pattern in both analysed populations. There was no difference in TGFβ1 (transforming growth factor β1) and VEGF (vascular endothelial growth factor) secretion measured by ELISA test and gene expression evaluated by real-time PCR. However, the expression of the gene for IL-1α (interleukin-1α) was 8-fold lower in oMSC (MSC isolated from old rats). These results indicate that aging individuals can be considered as candidates for autologous transplantation of bone-marrow-derived MSCs.     

A comprehensive classification of nucleic acid structural families based on strand direction and base pairing.

We propose a classification of DNA structures formed from 1 to 4 strands, based only on relative strand directions, base to strand orientation and base pairing geometries. This classification and its associated notation enable all nucleic acids to be grouped into structural families and bring to light possible structures which have not yet been observed experimentally. It also helps in understanding transitions between families and can assist in the design of multistrand structures.     

Effect of the myosin light chain kinase inhibitor ML-7 on the proteome of hearts subjected to ischemia-reperfusion injury

In the development of ischemia/reperfusion (I/R) injury, the role of the myosin light chain (MLC) phosphorylation has been given increased consideration. ML-7, a MLC kinase inhibitor, has been shown to protect cardiac function from I/R, however the exact mechanism remains unclear. Isolated rat hearts were perfused under aerobic conditions (controls) or subjected to I/R in the presence or absence of ML-7. Continuous administration of ML-7 (5 μM) from 10 min before onset of ischemia to the first 10 min of reperfusion resulted in significant recovery of heart contractility. Analysis of gels from two-dimensional electrophoresis revealed eight proteins with decreased levels in I/R hearts. Six proteins are involved in energy metabolism:ATP synthase beta subunit, cytochrome b-c1 complex subunit 1, 24-kDa mitochondrial NADH dehydrogenase, NADH dehydrogenase [ubiquinone] iron-sulfur protein 8, cytochrome c oxidase subunit, and succinyl-CoA ligase subunit. The other two proteins with decreased levels in I/R hearts are: peroxiredoxin-2 and tubulin. Administration of ML-7 increased level of succinyl-CoA ligase, key enzyme involved in the citric acid cycle. The increased level of succinyl-CoA ligase in I/R hearts perfused with ML-7 suggests that the cardioprotective effect of ML-7, at least partially, also may involve increase of energy production.     

Qualitative and quantitative composition of pigments in Phaeodactylum tricornutum (Bacillariophyceae) stressed by iron

The effect of Fe(III) deficiency on qualitative and quantitative changes in pigment composition in Phaeodactylum tricornutum Bohlin was demonstrated by HPLC and AAS. Maximum content of pigments showed the diatom cells incubated at the optimum iron concentration, i.e., 10 M. The contents of chlorophyll a, chlorophyll c ₁+c ₂, fucoxanthin, diadinoxanthin and ,-carotene were 109.99, 20.16, 40.39, 1.29 and 1.48 fg per cell, respectively. The results obtained showed that Fe(III) affected qualitative and quantitative pigment composition in P. tricornutum. The content of individual pigments, proportions between accompanying pigments and their ratios to chlorophyll a were important indicators of phytoplankton response to iron stress. The strong reduction in ,-carotene content, several times (2–5) increase in diadinoxanthin level as compared to ,-carotene, and high amount of diadinoxanthin in relation to chlorophyll a were observed in algae growing at very low Fe(III) concentrations, 0.001 and 0.01 M. The data suggested that phytoplankton pigments could be a potential physiological marker.     

Nitric oxide and platelet energy metabolism

This study was undertaken to determine whether nitric oxide (NO) can affect platelet responses through the inhibition of energy production. It was found that NO donors: S-nitroso-N-acetylpenicyllamine, SNAP, (5-50 microM) and sodium nitroprusside, SNP, (5-100 microM) inhibited collagen- and ADP-induced aggregation of porcine platelets. The corresponding IC50 values for SNAP and SNP varied from 5 to 30 microM and from 9 to 75 microM, respectively. Collagen- and thrombin-induced platelet secretion was inhibited by SNAP (IC50 = 50 microM) and by SNP (IC50 = 100 microM). SNAP (20-100 microM), SNP (10-200 microM) and collagen (20 microg/ml) stimulated glycolysis in intact platelets. The degree of glycolysis stimulation exerted by NO donors was similar to that produced by respiratory chain inhibitors (cyanide and antimycin A) or uncouplers (2,4-dinitrophenol). Neither the NO donors nor the respiratory chain blockers affected glycolysis in platelet homogenate. SNAP (20-100 microM) and SNP (50-200 microM) inhibited oxygen consumption by platelets. The effect of SNP and SNAP on glycolysis and respiration was not reduced by 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one, a selective inhibitor of NO-stimulated guanylate cyclase. SNAP (5-100 microM) and SNP (10-300 microM) inhibited the activity of platelet cytochrome oxidase and had no effect on NADH:ubiquinone oxidoreductase and succinate dehydrogenase. Blocking of the mitochondrial energy production by antimycin A slightly affected collagen-evoked aggregation and strongly inhibited platelet secretion. The results indicate that: 1) in porcine platelets NO is able to diminish mitochondrial energy production through the inhibition of cytochrome oxidase, 2) the inhibitory effect of NO on platelet secretion (but not aggregation) can be attributed to the reduction of mitochondrial energy production.     

Tandem immunoaffinity purification of protein complexes from Caenorhabditis elegans

The accurate determination of DNA concentration is essential for many processes in molecular biology and physiology and includes both gel- and cuvette-based methods. The recently introduced fluorescent dye, PicoGreen, has several advantages over other methods because it is sensitive and specific for double-stranded DNA (dsDNA). The dye is excited at 480 nm and emits at 520 nm when bound to dsDNA. This report describes the construction and use of PicoGmeter, a simple, inexpensive, fixed-wavelength fluorometer suitable for measuring PicoGreen fluorescence. PicoGmeter employs a blue light emitting diode (LED) for excitation and a photodiode to measure fluorescence. When compared to a commercially available instrument, PTI DeltaScan, the PicoGmeter performed admirably. Calibration curves for both instruments were superimposeable. Moreover, there was no significant difference between concentrations of DNA estimated by both instruments. A Bland and Altman analysis revealed that the PicoGmeter was equivalent to the PTI DeltaScan for estimating dsDNA concentration by the PicoGreen method. This simple, inexpensive, battery-operated fluorometer will allow investigators to employ the PicoGreen method without incurring the cost of purchasing a spectrofluorometer.     

Association between gravitational force and tissue metabolism in periparturient rats

Recently, interest in mammalian reproduction and offspring survival in altered gravity has been growing. Because successful lactation is critical for mammalian neonate survival, we have been studying the effect of gravity metabolism. We have shown an exponential relationship between glucose metabolic rate in mammary tissue of periparturient rats and an increase in gravity load. In this study we showed that changes in mammary metabolic rate due to gravity force were accompanied by a decrease in glucose metabolism in adipose tissue and by a reduced size of adipocytes. We assume that these changes are likely due to changes in prolactin or leptin levels related to altered gravity load.