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1.
Sci Total Environ ; 870: 161867, 2023 Apr 20.
Article in English | MEDLINE | ID: mdl-36716885

ABSTRACT

Microplastics (MPs) and nanoplastics (NPs) from mulch films and other plastic materials employed in vegetable and small fruit production pose a major threat to agricultural ecosystems. For conducting controlled studies on MPs' and NPs' (MNPs') ecotoxicity to soil organisms and plants and fate and transport in soil, surrogate MNPs are required that mimic MNPs that form in agricultural fields. We have developed a procedure to prepare MPs from plastic films or pellets using mechanical milling and sieving, and conversion of the resultant MPs into NPs through wet grinding, both steps of which mimic the degradation and fragmentation of plastics in nature. The major goal of this study was to determine if cryogenic exposure of two biodegradable mulch films effectively mimics the embrittlement caused by environmental weathering in terms of the dimensional, thermal, chemical, and biodegradability properties of the formed MNPs. We found differences in size, surface charge, thermal and chemical properties, and biodegradability in soil between MNPs prepared from cryogenically treated vs. environmentally weathered films, related to the photochemical reactions occurring in the environment that were not mimicked by cryogenic treatment, such as depolymerization and cross-link formation. We also investigated the size reduction process for NPs and found that the size distribution was bimodal, with populations centered at 50 nm and 150-300 nm, and as the size reduction process progressed, the former subpopulation's proportion increased. The biodegradability of MPs in soil was greater than for NPs, a counter-intuitive trend since greater surface area exposure for NPs would increase biodegradability. The result isassociated with differences in surface and chemical properties and to minor components that are readily leached out during the formation of NPs. In summary, the use of weathered plastics as feedstock would likely produce MNPs that are more realistic than cryogenically-treated unweathered films for use in experimental studies.

2.
J Colloid Interface Sci ; 590: 94-102, 2021 May 15.
Article in English | MEDLINE | ID: mdl-33524724

ABSTRACT

Bicontinuous microemulsions (BµEs) are a promising biomembrane mimetic system for investigating the behavior of antimicrobial peptides (AMPs) and their delivery to open wounds to combat antibiotic-resistant microorganisms. The properties of the BµE host are in turn affected by the guest AMP and can deviate from those of the unperturbed BµEs, especially at higher AMP concentrations. Here we report the effect of an archetypal AMP, melittin, over a wide range of concentrations, on the nanoscopic dynamics of BµEs formed by water/sodium dodecyl sulfate (SDS)/1-pentanol/dodecane, investigated using quasi-elastic neutron scattering (QENS). Two distinct motions are observed, namely, (i) the lateral motion of the surfactant on the surface of the oil channels and (ii) the internal motion of the surfactants. It is found that melittin restricts both the lateral and the internal motion, thereby acting as a stiffening agent. The lateral motion is more strongly affected, at low concentration of melittin. The lateral diffusion coefficient decreased sharply, approaching a constant value at higher melittin concentration. These results are in sharp contrast with the recent dynamic light scattering and neutron spin echo results which showed that at the length and time scales longer than those probed in the current work, melittin enhanced the long-range collective and local undulation motions of BµEs. Considered together, our results indicate that incorporation of melittin modulates the dynamics differently depending on the spatial and temporal regimes, in which the dynamics are being probed. The addition of melittin at low concentrations increased the magnitude of the zeta potential, but further increase of the melittin concentration decreased it. This suggests that addition of melittin at low concentrations led to increase in the surfactant concentration, but did not affect the negative charge per surfactant molecule, while further addition of melittin led to ion pairing of melittin with the oppositely charged surfactant. This study therefore demonstrates how the addition of melittin hinders the lateral motion of surfactants as a result of the strong association between melittin and SDS, suggesting that the release of AMPs from BµE-based delivery vehicles may be hindered.


Subject(s)
Melitten , Surface-Active Agents , Emulsions , Sodium Dodecyl Sulfate , Water
3.
Sci Total Environ ; 685: 1097-1106, 2019 Oct 01.
Article in English | MEDLINE | ID: mdl-31390700

ABSTRACT

Release of microplastics (MPs) and nanoplastics (NPs) into agricultural fields is of great concern due to their reported ecotoxicity to organisms that provide beneficial service to the soil such as earthworms, and the potential ability of MPs and NPs to enter the food chain. Most fundamental studies of the fate and transport of plastic particulates in terrestrial environments employ idealized MP materials as models, such as monodisperse polystyrene spheres. In contrast, plastics that reside in agricultural soils consist of polydisperse fragments resulting from degraded films employed in agriculture. There exists a need for more representative materials in fundamental studies of the fate, transport, and ecotoxicity of MPs and NPs in soil ecosystems. The objective of this study was therefore to develop a procedure to produce MPs and NPs from agricultural plastics (a mulch film prepared biodegradable polymer polybutyrate adipate-co-terephthalate (PBAT) and low-density PE [LDPE]), and to characterize the resultant materials. Soaking of PBAT films under cryogenic conditions promoted embrittlement, similar to what occurs through environmental weathering. LDPE and cryogenically-treated PBAT underwent mechanical milling followed by sieve fractionation into MP fractions of 840 µm, 250 µm, 106 µm, and 45 µm. The 106 µm fraction was subjected to wet grinding to produce NPs of average particle size 366.0 nm and 389.4 nm for PBAT and LDPE, respectively. A two-parameter Weibull model described the MPs' particle size distributions, while NPs possessed bimodal distributions. Size reduction did not produce any changes in the chemical properties of the plastics, except for slight depolymerization and an increase of crystallinity resulting from cryogenic treatment. This study suggests that MPs form from cutting and high-impact mechanical degradation as would occur during the tillage into soil, and that NPs form from the MP fragments in regions of relative weakness that possess lower molecular weight polymers and crystallinity.

4.
Toxicol In Vitro ; 52: 8-13, 2018 Oct.
Article in English | MEDLINE | ID: mdl-29807097

ABSTRACT

The coadjutant method for denture cleansing most used by denture wearers is immersion in chemical agents, which are toxic when in direct contact with cells. However, clinically, the contact between these chemical agents and prosthetic tissues does not occur directly, but rather with what remained impregnated into acrylic bases, even after rinsing the disinfected dentures. This study evaluated the antimicrobial and cytotoxic effects of a denture acrylic resin after successive cycles of daily overnight immersion in 1% sodium hypochlorite (1%NaClO) and 2% chlorhexidine digluconate (2%CHX), simulating the periods of 9 months or 1.5 year. Microbiological and cytotoxic assays were performed, respectively, by broth microdilution method (Candida albicans or Staphylococcus aureus) and MTT assay. Chemical residues of 2%CHX impregnated into the denture acrylic resin had an antimicrobial effect on both immersion periods, which was not observed with those of 1%NaClO. However, residues of 2%CHX were severely cytotoxic to human gingival fibroblasts compared to those of 1%NaClO and acrylic resin (not submitted to the denture cleansers), which were slightly cytotoxic. Even at low concentrations recommended for overnight soaking of removable dentures, the chemical residues of CHX may result in some degree of toxicity to the denture-bearing mucosa after long-term daily immersion.


Subject(s)
Acrylic Resins/toxicity , Anti-Infective Agents/toxicity , Chlorhexidine/analogs & derivatives , Denture Bases , Denture Cleansers/toxicity , Disinfectants/toxicity , Sodium Hypochlorite/toxicity , Candida albicans/drug effects , Cell Line , Chlorhexidine/toxicity , Fibroblasts/drug effects , Gingiva/cytology , Humans , Staphylococcus aureus/drug effects
5.
J Phys Chem Lett ; 7(13): 2394-401, 2016 Jul 07.
Article in English | MEDLINE | ID: mdl-27232190

ABSTRACT

The mechanism of action of antimicrobial peptides is traditionally attributed to the formation of pores in the lipid cell membranes of pathogens, which requires a substantial peptide to lipid ratio. However, using incoherent neutron scattering, we show that even at a concentration too low for pore formation, an archetypal antimicrobial peptide, melittin, disrupts the regular phase behavior of the microscopic dynamics in a phospholipid membrane, dimyristoylphosphatidylcholine (DMPC). At the same time, another antimicrobial peptide, alamethicin, does not exert a similar effect on the DMPC microscopic dynamics. The melittin-altered lateral motion of DMPC at physiological temperature no longer resembles the fluid-phase behavior characteristic of functional membranes of the living cells. The disruptive effect demonstrated by melittin even at low concentrations reveals a new mechanism of antimicrobial action relevant in more realistic scenarios, when peptide concentration is not as high as would be required for pore formation, which may facilitate treatment with antimicrobial peptides.

6.
J Phys Chem B ; 120(1): 154-63, 2016 Jan 14.
Article in English | MEDLINE | ID: mdl-26673405

ABSTRACT

Vitamin E behaves as an antioxidant and is well known for its protective properties of the lipid membrane. The most biologically active form of vitamin E in the human organism is α-tocopherol (aToc). Very recently (Marquardt, D.; et al. J. Am. Chem. Soc. 2014, 136, 203-210) it has been shown that aToc resides near the center of dimyristoylphosphatidylcholine (DMPC) bilayer, which is in stark contrast with other PC membranes, where aToc is located near the lipid-water interface. Here we report an unusual effect of this exceptional location of aToc on the dynamical behavior of DMPC membrane probed by incoherent elastic and quasielastic neutron scattering. For pure DMPC vesicles, elastic scan data show two step-like drops in the elastic intensity at 288 and 297 K, which correspond to the pre- and main phase transitions, respectively. However, inclusion of aToc into DMPC membrane inhibits the step-like elastic intensity drops, indicating a significant impact of aToc on the phase behavior of the membrane. This observation is supported by our differential scanning calorimetry data, which shows that inclusion of aToc leads to a significant broadening of the main phase transition peak, whereas the peak corresponding to the pretransition disappears. We have performed quasielastic neutron scattering (QENS) measurements on DMPC vesicles with various concentrations of aToc at 280, 293, and 310 K. We have found that aToc affects both the lateral diffusion and the internal motions of the lipid molecules. Below the main phase transition temperature inclusion of aToc accelerates both the lateral and the internal lipid motions. On the other hand, above the main phase transition temperature the addition of aToc restricts only the internal motion, without a significant influence on the lateral motion. Our results support the finding that the location of aToc in DMPC membrane is deep within the bilayer.


Subject(s)
Dimyristoylphosphatidylcholine/chemistry , Lipid Bilayers/chemistry , Thermodynamics , alpha-Tocopherol/chemistry , Calorimetry , Humans , Molecular Structure , Neutrons , Scattering, Radiation
7.
Soft Matter ; 11(34): 6755-67, 2015 Sep 14.
Article in English | MEDLINE | ID: mdl-26212615

ABSTRACT

Antimicrobial peptides are universal in all forms of life and are well known for their strong interaction with the cell membrane. This makes them a popular target for investigation of peptide-lipid interactions. Here we report the effect of melittin, an important antimicrobial peptide, on the dynamics of membranes based on 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid in both the solid gel and fluid phases. To probe the phase transition, elastic neutron intensity temperature scans have been carried out on DMPC-based unilamellar vesicles (ULV) with and without melittin. We have found that addition of a small amount (0.2 mol%) melittin eliminates the steep fall in the elastic intensity at 296 K associated with the solid gel to fluid phase transition, which is observed for pure DMPC vesicles. Quasielastic neutron scattering (QENS) experiments have been carried out on DMPC ULV in the solid gel and fluid phases with and without 0.2 mol% melittin. The data analysis invariably shows the presence of lateral and internal motions of the DMPC molecule. We found that melittin does have a profound effect on the dynamics of lipid molecules, especially on the lateral motion, and affects it in a different way, depending on the phase of the bilayers. In the solid gel phase, it acts as a plasticizer, enhancing the lateral motion of DMPC. However, in the fluid phase it acts as a stiffening agent, restricting the lateral motion of the lipid molecules. These observations are consistent with the mean squared displacements extracted from the elastic intensity temperature scans. Their importance lies in the fact that many membrane processes, including signaling and energy transduction pathways, are controlled to a great extent by the lateral diffusion of lipids in the membrane. To investigate the effect of melittin on vesicles supplemented with cholesterol, QENS experiments have also been carried out on DMPC ULV with cholesterol in the presence and absence of 0.2 mol% melittin. Remarkably, the effects of melittin on the membrane dynamics disappear in the presence of 20 mol% cholesterol. Our measurements indicate that the destabilizing effect of the peptide melittin on membranes can be mitigated by the presence of cholesterol. This study might provide new insights into the mechanism of action of antimicrobial peptides and their selective toxicity towards foreign microorganisms.


Subject(s)
Cell Membrane/drug effects , Cholesterol/metabolism , Dimyristoylphosphatidylcholine/metabolism , Lipid Bilayers/chemistry , Lipid Bilayers/metabolism , Melitten/pharmacology , Cell Membrane/chemistry , Cell Membrane/metabolism , Melitten/metabolism , Temperature , Unilamellar Liposomes/chemistry , Unilamellar Liposomes/metabolism
8.
J Phys Chem B ; 119(12): 4460-70, 2015 Mar 26.
Article in English | MEDLINE | ID: mdl-25738532

ABSTRACT

The dynamics of phospholipids in unilamellar vesicles (ULVs) is of interest in biology, medical, and food sciences, since these molecules are widely used as biocompatible agents and a mimic of cell membrane systems. We have investigated the nanoscopic dynamics of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) phospholipid in ULVs as a function of temperature using elastic and quasielastic neutron scattering (QENS). The dependence of the signal on the scattering momentum transfer, which is a critical advantage of neutron scattering techniques, allows the detailed analysis of the lipid motions that cannot be carried out by other means. In agreement with a differential scanning calorimetry measurement, a sharp rise in the elastic scattering intensity below ca. 296 K indicates a phase transition from the high-temperature fluid phase to the low-temperature solid gel phase. The microscopic lipid dynamics exhibits qualitative differences between the solid gel phase (in a measurement at 280 K) and the fluid phase (in a measurement at a physiological temperature of 310 K). The analysis of the data demonstrates the presence of two types of distinct motions: the entire lipid molecule motion within a monolayer, also known as lateral diffusion, and the relatively faster internal motion of the DMPC molecule. The lateral diffusion of the entire lipid molecule is Fickian in character, whereas the internal lipid motions are of localized character, which is consistent with the structure of the vesicles. The lateral motion slows down by an order of magnitude in the solid gel phase, whereas for the internal motion not only the time scale but also the character of the motion changes upon the phase transition. In the solid gel phase, the lipids are more ordered and undergo uniaxial rotational motion. However, in the fluid phase, the hydrogen atoms of the lipid tails undergo confined translation diffusion rather than uniaxial rotational diffusion. The translational, but spatially localized, diffusion of the hydrogen atoms of the lipid tails is a manifestation of the flexibility of the chains acquired in the fluid phase. Because of this flexibility, both the local diffusivity and the confinement volume for the hydrogen atoms increase in the linear fashion from near the lipid's polar headgroup to the end of its hydrophobic tail. Our results present a quantitative and detailed picture of the effect of the gel-fluid phase transition on the nanoscopic lipid dynamics in ULVs. The data analysis approach developed here has a potential for probing the dynamic response of lipids to the presence of additional cell membrane components.


Subject(s)
Dimyristoylphosphatidylcholine/chemistry , Gels/chemistry , Phase Transition , Unilamellar Liposomes/chemistry , Calorimetry, Differential Scanning , Elasticity , Hydrogensulfite Reductase/chemistry , Motion , Neutron Diffraction , Temperature
9.
Oral Dis ; 21(1): 57-65, 2015 Jan.
Article in English | MEDLINE | ID: mdl-24219354

ABSTRACT

OBJECTIVE: The antimicrobial action of five drugs incorporated in temporary denture relines on the fungal biofilm was evaluated. MATERIALS AND METHODS: A Candida albicans biofilm (SC5314) was formed on specimens (10 × 1 mm) of materials (Trusoft and Softone) modified or not (control) by the drugs (nystatin, miconazole, ketoconazole, itraconazole, and chlorhexidine diacetate). Cell viability was determined spectrophotometrically by the tetrazolium salt reduction assay (XTT) after 24 h, 48 h, and 7 and 14 days of incubation. The minimum inhibitory concentrations (MICs) were those which inhibited 90% or more of fungal growth. Fungal susceptibility was confirmed by confocal laser scanning microscopy analysis. RESULTS: The MICs of drugs incorporated in the materials were 0.032, 0.256, 0.128, 0.256, and 0.064 g ml(-1) for nystatin, miconazole, ketoconazole, itraconazole, and chlorhexidine, respectively. Images from nystatin, chlorhexidine, and ketoconazole demonstrated no viable cells. CONCLUSIONS: The antimicrobials incorporated in the resilient materials inhibited fungal growth during 14 days, with lower MICs for nystatin and chlorhexidine.


Subject(s)
Antifungal Agents/pharmacology , Biofilms/drug effects , Candida albicans/drug effects , Denture Liners/microbiology , Biofilms/growth & development , Candida albicans/growth & development , Chlorhexidine , Itraconazole/pharmacology , Ketoconazole/pharmacology , Miconazole/pharmacology , Microbial Sensitivity Tests , Nystatin/pharmacology
10.
Eur J Prosthodont Restor Dent ; 22(2): 56-61, 2014 Jun.
Article in English | MEDLINE | ID: mdl-25134362

ABSTRACT

The colour stability of acrylic resin denture teeth in beverages was investigated. A spectrophotometer measured the colour (CIE-L*a*b* system) of all specimens after storage in distilled water/for 24 h at 37 degrees C (T0). Specimens were then immersed in various beverages. After 15 days (T1) and 30 days (T2), for each material, the mean deltaE values were calculated and compared by two-way ANOVA and Tukey intervals (alpha = 0.05). In the deltaT0T1 period, specimens stored in red wine were significantly discoloured, compared to distilled water (P = 0.003). There was no difference between immersion solutions in deltaET0T2 (P = 0.772) and in deltaET1T2 (P = 0.058), and no difference between materials in all immersion periods.


Subject(s)
Acrylic Resins/chemistry , Beverages , Dental Materials/chemistry , Tooth, Artificial , Carbonated Beverages , Coffee , Color , Humans , Immersion , Materials Testing , Spectrophotometry/methods , Surface Properties , Temperature , Time Factors , Water/chemistry , Wine
11.
Oral Dis ; 20(4): 329-44, 2014 May.
Article in English | MEDLINE | ID: mdl-23679136

ABSTRACT

In healthy individuals, Candida species are considered commensal yeasts of the oral cavity. However, these microorganisms can also act as opportunist pathogens, particularly the so-called non-albicans Candida species that are increasingly recognized as important agents of human infection. Several surveys have documented increased rates of C. glabrata, C. tropicalis, C. guilliermondii, C. dubliniensis, C. parapsilosis, and C. krusei in local and systemic fungal infections. Some of these species are resistant to antifungal agents. Consequently, rapid and correct identification of species can play an important role in the management of candidiasis. Conventional methods for identification of Candida species are based on morphological and physiological attributes. However, accurate identification of all isolates from clinical samples is often complex and time-consuming. Hence, several manual and automated rapid commercial systems for identifying these organisms have been developed, some of which may have significant sensitivity issues. To overcome these limitations, newer molecular typing techniques have been developed that allow accurate and rapid identification of Candida species. This study reviewed the current state of identification methods for yeasts, particularly Candida species.


Subject(s)
Candida/classification , Candida/isolation & purification , Candida/genetics , Humans , Mycological Typing Techniques/methods , Phenotype
12.
J Plast Reconstr Aesthet Surg ; 59(12): 1348-9, 2006.
Article in English | MEDLINE | ID: mdl-17113516

ABSTRACT

In rare cases the usage of the internal thoracic vessels as recipient vessels in reconstructive surgery of the head and neck region with free tissue transfer is a challenging but valid alternative if local recipient vessels are unusable.


Subject(s)
Carcinoma, Squamous Cell/surgery , Hypopharyngeal Neoplasms/surgery , Mammary Arteries/surgery , Plastic Surgery Procedures/methods , Surgical Flaps/blood supply , Humans , Male , Microsurgery/methods , Middle Aged
13.
J Chem Phys ; 124(17): 174908, 2006 May 07.
Article in English | MEDLINE | ID: mdl-16689605

ABSTRACT

The deformed structure of silica-filled elastomers under uniaxial strain has been investigated using a combination of both small angle x-ray scattering and small angle neutron scattering methods. Using an extraction procedure and taking into account the two-phase nature of these polymer-based composites, the single chain scattering behavior as well as filler properties could be obtained uniquely on identical samples. For the first time the deformation of the rubbery matrix on the length scale of the network chain in a filled rubber could be determined and therewith the importance of matrix overstrain for the mechanical properties was estimated. Additionally, the determination of filler deformation and filler destruction presents microscopic details of the mechanisms of filler networking and the stress-softening Mullins effect.

14.
Biomed Chromatogr ; 20(4): 369-76, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16177959

ABSTRACT

Two high-performance liquid chromatographic methods for determination of residual monomer in dental acrylic resins are described. Monomers were detected by their UV absorbance at 230 nm, on a Nucleosil C18 (5 microm particle size, 100 A pore size, 15 x 0.46 cm i.d.) column. The separation was performed using acetonitrile-water (55:45 v/v) containing 0.01% triethylamine (TEA) for methyl methacrylate and butyl methacrylate, and acetonitrile-water (60:40 v/v) containing 0.01% TEA for isobutyl methacrylate and 1,6-hexanediol dimethacrylate as mobile phases, at a flow rate of 0.8 mL/min. Good linear relationships were obtained in the concentration range 5.0-80.0 microg/mL for methyl methacrylate, 10.0-160.0 microg/mL for butyl methacrylate, 50.0-500.0 microg/mL for isobutyl methacrylate and 2.5-180.0 microg/mL for 1,6-hexanediol dimethacrylate. Adequate assay for intra- and inter-day precision and accuracy was observed during the validation process. An extraction procedure to remove residual monomer from the acrylic resins was also established. Residual monomer was obtained from broken specimens of acrylic disks using methanol as extraction solvent for 2 h in an ice-bath. The developed methods and the extraction procedure were applied to dental acrylic resins, tested with or without post-polymerization treatments, and proved to be accurate and precise for the determination of residual monomer content of the materials evaluated.


Subject(s)
Acrylic Resins/chemistry , Chromatography, High Pressure Liquid/methods , Dental Materials/chemistry , Methacrylates/analysis , Methylmethacrylate/analysis , Calibration , Chemical Fractionation/methods , Reproducibility of Results , Spectrophotometry, Ultraviolet
15.
Langmuir ; 21(10): 4324-7, 2005 May 10.
Article in English | MEDLINE | ID: mdl-16032842

ABSTRACT

In this paper, the ordering in concentrated charge stabilized colloidal dispersions is considered. Despite the impressive Bragg reflections obtained for shear ordered dispersions by light (LS), small-angle neutron (SANS), and small-angle X-ray scattering (SAXS), a number of open questions remain. Sheared dispersions are usually ordered in layers. For such systems, two questions arise: (1) What is the structure in a layer? (2) What is the stacking structure perpendicular to the layers? The second question requires a method to determine the structure perpendicular to the layers. Although originally interested only in structural aspects, we were forced to consider different methods. Two methods are treated both applicable to neutron and X-ray scattering from concentrated dispersions. One has been used by physicists and chemists for many years to determine the structure of crystals by sample rotation. In colloid science, we have used it previously in neutron and X-ray scattering. A second method is treated here which can be applied in small-angle scattering from a Couette cell. It gives the scattering intensity in a certain direction without sample rotation. Although very useful with the Couette cell, it cannot be found in any of the well-known references on colloid science. A theoretical explanation and experimental examples obtained by synchrotron X-ray scattering from a Couette cell are given in the paper.

17.
Phys Rev Lett ; 89(13): 135502, 2002 Sep 23.
Article in English | MEDLINE | ID: mdl-12225034

ABSTRACT

We investigate the microscopic mechanisms responsible for microdomain alignment in block copolymer solutions exposed to an electric field. Using time-resolved synchrotron small-angle x-ray scattering, we reveal two distinct processes, i.e., grain boundary migration and rotation of entire grains, as the two dominant microscopic mechanisms. The former dominates in weakly segregating systems, while the latter is predominant in strongly segregated systems. The kinetics of the processes are followed as a function of polymer concentration and temperature and are correlated to the solution viscosity.

18.
Z Orthop Ihre Grenzgeb ; 140(1): 72-6, 2002.
Article in German | MEDLINE | ID: mdl-11898068

ABSTRACT

AIM: The aim of this study is to prove the intra- and interobserver reliability of three different methods to measure the active range-of-motion in the forearm. METHODS: These three different methods were tested on forty volunteers. In the first method pictures were made in full supination and pronation, measurement of the two angles was performed with a dedicated software. Active range-of-motion was defined as the magnitude of forearm rotation between maximum pronation and supination. The second method used a standard goniometer. The third method of assessment used a gravity goniometer (plurimeter). We randomised both the side of the patient to be examined and the sequence of the methods. Two examiners measured subsequently the range-of-motion twice with these three devices. RESULTS: We found a significant intraobserver reproducibility with the gravity goniometer. There was no significance with the goniometer or pictures. The intraobserver reproducibility of the latter two methods was poor. The interobserver reproducibility of the gravity goniometer and pictures was significant, for the goniometer it was poor. Agreement between the pictures and gravity goniometer assessment of the range-of-motion was good. None of these two methods was significantly correlated with the goniometer assessment. CONCLUSION: For reproducibility of measurement of range-of-motion in the forearm the gravity goniometer is the best method, although the measured values were 5 % greater.


Subject(s)
Elbow Joint/physiology , Forearm/physiology , Range of Motion, Articular/physiology , Wrist Joint/physiology , Adult , Diagnosis, Computer-Assisted/instrumentation , Female , Humans , Male , Observer Variation , Pronation/physiology , Reproducibility of Results , Software , Supination/physiology
19.
Phys Med Biol ; 47(4): 577-92, 2002 Feb 21.
Article in English | MEDLINE | ID: mdl-11900192

ABSTRACT

Small-angle x-ray scattering (SAXS) patterns are recorded from thin breast tissue samples containing healthy and cancerous regions. The SAXS patterns are compared with histo-pathological observations. The information available from SAXS is reviewed, and a model for scattering from collagen is presented. Scattering patterns of collagen at regions far from the tumours are essentially different from those at tumours. The axial period of collagen fibrils is 65.0 +/- 0.1 nm in healthy regions, and 0.3 nm larger in cancer-invaded regions. The average intensity of scattering from cancerous regions is an order of magnitude higher than the intensity from healthy regions. This is interpreted to arise from an increase of the specific surface area of the scatterers, which is due to a disruption of the molecular and supra-molecular structures in cancerous regions and invasion of new types of cells. The differences of the SAXS patterns are large and distinctive enough to suggest that these phenomena may be utilized in mammography.


Subject(s)
Breast Neoplasms/diagnostic imaging , Breast Neoplasms/pathology , Breast/pathology , Mammography , Scattering, Radiation , Collagen/metabolism , Female , Humans , Models, Statistical , Time Factors , X-Ray Diffraction , X-Rays
20.
Klin Monbl Augenheilkd ; 216(2): 105-11, 2000 Feb.
Article in German | MEDLINE | ID: mdl-10730227

ABSTRACT

BACKGROUND: The aim of this retrospective study is to evaluate the difference in postoperative intraocular pressure (IOP) control, number of antiglaucoma medications and visual acuity (VA) between combined phacoemulsification and trabeculectomy (Glaucoma triple) surgery and two-stage procedures with trabeculectomy first and cataract extraction later. PATIENTS AND METHODS: Two groups of glaucoma patients were assessed: In group 150 consecutive patients undergoing combined phacoemulsification and trabeculectomy were enrolled. In group two, 51 consecutive patients were included, that had undergone trabeculectomy first and cataract surgery later. The mean interval between the two procedures was 3.2 years, 35/51 patients (71%) underwent conventional extracapsular cataract extraction, the other 16 patients (29%) had phacoemusification via clear cornea incision. RESULTS: One year postoperative both groups revealed a significant IOP reduction. IOP-reduction was significantly better in the two-stage group one year after trabeculectomy (12.8 +/- 4.0 mm Hg) and one year after cataract extraction (14.0 +/- 2.8 mm Hg) as compared to the combined surgery group (15.3 +/- 4.0 mm Hg). Kaplan-Meier survival analysis revealed a 90% success-rate 12 months after trabeculectomy only as compared to 65% success-rate in the combined surgery group. The number of antiglaucoma medications was significantly reduced in both groups. One year after cataract surgery no difference in VA could be seen between the two groups. CONCLUSIONS: If medically uncontrolled glaucoma with advanced optic nerve head changes in patients with coexisting glaucoma and cataracts is the main indication for surgery, a two-stage procedure (i.e. trabeculectomy first, cataract extraction later) yields better long-term IOP control. If glaucoma is medically controlled with a simple regimen, conjunctiva-sparing cataract surgery may be the treatment of choice. In all other cases of coexisting glaucoma and cataract combined phacoemulsification and trabeculectomy (Glaucoma triple) is preferrable, either performed through a single incision or as two separate procedures in the same session (i.e. trabeculectomy from above, phacoemulsifiaction via clear cornea from temporal).


Subject(s)
Cataract Extraction/methods , Glaucoma/surgery , Trabeculectomy/methods , Age Factors , Aged , Aged, 80 and over , Cataract/complications , Cataract Extraction/adverse effects , Female , Glaucoma/complications , Humans , Male , Middle Aged , Ocular Hypertension , Retrospective Studies , Time Factors , Trabeculectomy/adverse effects , Treatment Outcome
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