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At least 217 records · Page 12Linked to original sources
PubMed1995

Histologic observations of bone remodeling adjacent to endosteal dental implants.

To examine bone morphology associated with endosteal dental implants at various time intervals, we inserted 20 one-stage and 20 two-stage titanium blade implants and 20 one-stage and 20 two-stage titanium root-form implants into 30 dog mandibles. Sixteen implants in 6 control (c) dogs (in situ five months) did not receive bridgework. Sixty-four implants in 24 dogs supported bridges for six, 12, 18, or 24 months. The entire area of the mandible containing the implants was examined by routine light and Nomarski differential interference microscopy (NM) for bone morphology (including osteon orientation) at the implant surface and at regions away from the implant. Control root-form implants were apposed by woven bone, with homogenous compact bone in the cortical plate distant to the implant. After 6 mo of load, immature bone was predominant apposing the implant, but initial osteonal maturation was apparent. NM clearly demonstrated the interstitial and concentric lamellae of the bone. Surprisingly, compact bone formed internal to the cortical plate, an area where trabecular bone is expected. At later periods of load, more mature osteons were seen apposing the implants; however remodeling events were still apparent. These remodeling events extend further away from the implant than was expected if the events resulted only from surgical repair. Also, when the implant inclined so that half was totally in the cortical plate and half in the marrow (in trabecular patterns), osteonal bone appeared to remodel in both areas. Control blade implants and blades loaded for six months were apposed by immature osteons when the implant was placed into the cortical plate. A trabecular meshwork was inferior to the osteonal bone. At 12 mo of load, the bone internal to the cortical plate appeared similar to the lamina dura supporting teeth; however, no PDL existed; the lamina-dura-like pattern directly apposed the implant. Even after 24 mo of load, extensive bone remodeling was apparent adjacent to the implant, markedly different from the bone making up the existing cortical plate. From these data, remodeling activities to blade implants may involve the development of a lamina-dura-like bone morphology after longer periods of load. Osteonal bone was apparent, but only at regions where the implant was inserted into the cortical plate. Further, bone remodeling was apparent even after long periods of load.

Alveolar Process↗
PubMed1988

Growth cone configuration and advance: a time-lapse study using video-enhanced differential interference contrast microscopy.

We have analyzed the dynamics of growth cone configuration using video-enhanced contrast differential interference contrast microscopy. Regenerating neurites from NGF-treated PC12 cells and sympathetic neurons were observed in real time during their elongation and reviewed by time-lapse video recordings. This technique provided a high-resolution view of motile growth cone elements including filopodia, microspikes, lamellipodia and ruffles. On the basis of our observations, a multistage model for growth cone advance is proposed. Elongation commences with lamellipodial spreading. If the newly extended lamellipodium does not retract or lift off the substrate in the form of a ruffle, a second phase--consolidation--occurs, in which the lamellipodium thickens as it fills with cytoplasm and organelles. The consolidated area then undergoes further transformation into an area of neuritic shaft as new lamellipodia form at the leading and peripheral zones of the distal process. We never observed filopodia or microspikes contracting to propel the growth cone forward. We also noted that elongating tips generally had large varicosities within 20 micron of their leading edges. These may play a role in neurite outgrowth and in the formation of smaller, synaptic vesicle-containing varicosities. The dynamic behavior of the growth cone was under the control of NGF. Withdrawal of NGF resulted in the disappearance of motile structures and cessation of growth, while readdition of NGF triggered the rapid reappearance of these structures and the resumption of growth. The high-resolution video microscopy of living growth cones provides necessary baseline information, as well as a bioassay paradigm, for future studies on the molecular mechanisms of nerve growth.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

Wavelength-dependent roughness: a quantitative approach to characterizing the topography of rough titanium surfaces.

Topographies of grit-blasted, etched, grit-blasted and etched, and microfabricated and etched surfaces of commercially pure titanium have been investigated. Such surface topographies vary across the scale range of interest for dental implants, extending from nanometers to millimeters. The complete characterization of topography requires the use of complementary methods. This study compared the topographic characterization methods of non-contact laser profilometry, interference microscopy, stereo-scanning electron microscopy (stereo-SEM), and atomic force microscopy. Non-contact laser profilometry was shown to be a useful method to characterize topographic features in the micron to millimeter range, whereas interference microscopy and stereo-SEM can be employed down to the submicron range. Stereo-SEM is particularly useful for quantifying topographies with complex, strongly corrugated ("sharp"), and high-aspect-ratio features and was shown to be complementary to non-contact laser profilometry and interference microscopy. Because of tip-related envelope problems, atomic force microscopy was not found to be suitable for the type of surfaces investigated in this study. Independent of the method used, the commonly used "integral" amplitude roughness parameters, such as Ra, Rq, or Rt, were often of limited value in the description of actual implant surfaces. The application of the wavelength-dependent roughness approach was shown to be an effective method for the description of surface topographies in the complete range of characteristic roughness and is also a useful means of examining the effects of surface treatment processes.

Analysis of Variance↗
PubMed1976

[Early stages of myocardial infarct studied by opitcal methods].

The hearts of 45 dogs were investigated at times from 10 minutes to 24 hours following ligation of the anterior interventricular branch of the left coronary artery. The material was fixed in formalin and embedded in parafin. It was established that at early stages of experimental myocardial infarction in the zone of eschemia there took place eschemic zone various foms of contactural damages, lumpy decmposition, relaxation and sarcoplasmic matrix. By the polarizing microscope method in the peripheral area of the eshemic zone various forms of contractural damages, lumpy decomposition, relaxation and desaggregation of myofibrills, were noted. Phaso-contrast and interference microscopy investigations revealed in the damaged cells an induration of the sarcoplasmic matrix due to an increase in the dry matter concentration. The studies conducted with the help of polarizing, phaso-contrast, and interference microscopy methods showed that by using these methods it is possible at early periods to reveal the zone of myocardial infarction on stained and unstained preparations prepared by conventional methods.

Animals↗
PubMed2002

Application of Nomarski interference contrast microscopy as a thickness monitor in the preparation of transparent, SiC-based, cross-sectional TEM samples.

Reflected light optical microscopy using a Nomarski prism and a differential interference contrast filter have been employed in concert to achieve a technique that provides an accurate color reference for thickness during the dimpling and ion milling of transparent transmission electron microscopy samples of 6H-SiC(000 1) wafers. The samples had thin films of AIN, GaN, and Au deposited on the SiC substrate. A sequence of variously colored primary and secondary interference bands was observed when the SiC was thinner than 20 microm using an optical microscope. The color bands were correlated with the TEM sample thickness as measured via scanning electron microscopy. The interference contrast was used to provide an indication of the dimpling rate, the ion milling rate, and also the most probable location of perforation, which are useful to reduce sample breakage. The application of pressure during the initial cross-sectional preparation reduced the separation of the two halves of the sample sandwich and resulted in increased shielding of the film surface from ion milling damage.

Journal Article↗
PubMed1978

Interference reflection microscopy of adhesion of Amoeba proteus.

A simple method of observing the adhesive behaviour of large cells by means of interference reflection microscope is described, and some observations of monopodial Amoeba proteus are presented. Amoebae may contact with the substratum at any point along the long axis of the cells. Points of contact are usually few, small and temporary. Frequently the cell surface within the contact points oscillates, changing the separation distance from the substratum.

Amoeba↗
PubMed1993

Elongation of growth cone filopodia observed with video-enhanced differential interference contrast microscopy.

Dynamics of filopodia configuration from growth cones of neurons isolated from the rat central nervous system were analyzed by using video-enhanced differential interference contrast microscopy. Rapid elongation of filopodia from growth cones and dendrites was observed when high K+ Krebs solution was applied to the growth cones. The maximum speed of the elongation was about 1 micron/s. The filopodia suspended in control Krebs solution moved at random. Retraction of the filopodia was observed within a few minutes after high K+ stimulation.

Animals↗
PubMed1999

Reflection interference contrast microscopy combined with scanning force microscopy verifies the nature of protein-ligand interaction force measurements.

The integration of a stand-alone scanning force microscope (SFM) scanner with a reflection interference contrast microscope (RICM) makes it possible to measure directly the separation distance between the SFM probe and the sample surface. The SFM-RICM combination, when applied to the force measurements between ligand-derivatized SFM probe and a protein receptor-derivatized surface, showed that the anomalous force discontinuities often observed for such interacting pairs were indeed a real behavior characteristic of a particular experimental configuration. Apart from small discrepancies due to transient damping, commercially available cantilevers did behave in an ideal mechanical fashion, thus indicating that protein-ligand unbinding events were occurring at distances much larger than their maximum extended length. This external verification of separation distance requires a closer examination of the physical events occurring upon detachment of the surfaces. An alternative interpretation of such force measurements is proposed here in which the protein and/or ligand immobilization chemistry is called into question.

Biophysical Phenomena↗
PubMed1988

[Morphologic changes in urine erythrocytes in interference contrast microscopy as an indication of the source of microhematuria].

According to Birch and Fairley (1, 2, 3) it is possible to differentiate glomerular from nonglomerular microhematuria by red cell morphology. Using an interference contrast microscope we examined urine sediments of 85 patients characterized by a microhematuria with more than 8000 red cells/ml urine. Examination of 31 patients with glomerular disease and 27 patients with nonglomerular disease yielded a correlation of 83.5 and 88% respectively between our results and the verified cause of microhematuria. In contrast red cell morphology did not prove any diagnostic favour in 27 patients with renal transplantation.

Diagnosis, Differential↗
PubMed1993

The use of urinary red cell morphology to determine the source of hematuria in children.

Urinary red cell morphology has been used to indicate the source of renal tract bleeding. A double blind study was undertaken to evaluate the reliability of urinary red cell morphology in predicting the source of hematuria in a pediatric population. Two independent observers used phase-contrast microscopy, one also using Nomarski differential interference microscopy, to examine 101 urine specimens from 90 pediatric patients with hematuria. 28 cases were subsequently excluded because the clinical diagnosis was uncertain. In the remaining 62 patients the laboratory diagnosis based on the erythrocyte morphology was compared with the primary clinical diagnosis. Observer 1 documented dysmorphic red cells in 40 of 42 patients with glomerulonephritis, and isomorphic red cells in 19 of the 20 cases of non-glomerular bleeding. Observer 2 documented dysmorphic red cells in 39 of the 42 glomerular lesions, and isomorphic red cells in all of the non-glomerular lesions. This represents a sensitivity for predicting glomerular hematuria of 95% for observer 1 and 93% for observer 2, and a specificity of 95% and 100% respectively. There was no definite advantage in the use of Nomarski compared to phase-contrast microscopy. These results confirm the accuracy of this technique in predicting the source of hematuria in pediatric patients.

Child↗
PubMed1992

Immunogold and fluorescein immunolabelling of Legionella pneumophila within an aquatic biofilm visualized by using episcopic differential interference contrast microscopy.

Biofilms containing diverse microflora were developed in tap water on glass and polybutylene surfaces. Legionella pneumophila within the biofilms was labelled with monoclonal antibodies and visualized with immunogold or fluorescein isothiocyanate conjugates. Development of a differential interference contrast technique in an episcopic mode enabled simultaneous visualization of the total biofilm flora and gold-labelled legionellae. The legionellae occurred in microcolonies within the biofilm in the absence of amoebae, suggesting that the bacterial consortium was supplying sufficient nutrients to enable legionellae to grow extracellularly within the biofilm.

Antibodies, Monoclonal↗
PubMed2002

Application of laser scanning cytometry followed by epifluorescent and differential interference contrast microscopy for the detection and enumeration of Cryptosporidium and Giardia in raw and potable waters.

AIMS: The main goal of this study was to validate a new laser scanning cytometry method (ChemScanRDI) that couples immunofluorescence detection with differential interference contrast (DIC) confirmation, against manual microscopic enumeration of Giardia and Cryptosporidium (oo)cysts. This study also assessed the basic performance of the new Association Française de Normalisation (AFNOR) NF T 90-455 method for Giardia and Cryptosporidium (oo)cyst enumeration with respect to (oo)cyst yield, linearity, repeatability, influence of turbidity and detection limit in raw and potable waters. METHODS AND RESULTS: The new standard method relies on cartridge (Envirocheck) filtration, immunomagnetic separation purification, immunofluorescence staining and detection followed by DIC confirmation. The recovery was 30-50% for both parasites at seeding levels from 30 to 230 (oo)cysts. The method is linear from 0 to around 400 seeded (oo)cysts and the yield does not significantly vary for turbidity levels from 10 to 40 Formazin Nephelometric Units (FNU). The results were obtained using manual microscopic enumeration of the (oo)cysts. The ChemScanRDI yielded counts that were at least equivalent to those obtained using manual microscopy for both parasites in raw and potable water concentrates, for seeding levels of 10-300 or 10-100, respectively. The purification and labelling method proposed by the supplier of theChemScanRDI (Chemunex) reached very similar recoveries to the AFNOR protocol (70-86% in both cases). CONCLUSIONS: Laser scanning cytometry can be used as a more standardized alternative to manual enumeration as part of the new AFNOR standard method. SIGNIFICANCE AND IMPACT OF THE STUDY: By using laser scanning cytometry instead of manual microscopy, laboratories could circumvent the limitations of manual microscopy, namely: low sample throughput, operator subjectivity and operator fatigue. The study further supports the drive to incorporate laser scanning cytometry in the standard methods for Giardia and Cryptosporidium enumeration.

Animals↗
PubMed1980

Influence of aqueous fixation on articular surface morphology. A reflected light interference microscope study.

Fresh, unfixed temporomandibular fibrous articular surfaces from baboons were examined by reflected light interference microscopy. The appearances, recorded photographically, were compared with those of joints subjected to aqueous fixation in buffered glutaraldehyde and formalin. Fixation caused readily detectable, measureable changes in articular surface morphology. Reflected light interference microscopy is a valuable technique for the demonstration of the effects of fixation on articular surface morphology.

Aldehydes↗
PubMed1994

Differential interference contrast microscopy combined with immunofluorescence: a new method to phenotype eosinophils in situ.

Several surface receptors are expressed on eosinophils in vitro depending on the state of cellular activation, but immunohistochemical studies of eosinophil-related diseases have mostly focused on the number of infiltrating eosinophils as well as extracellular deposits of eosinophil granule proteins. The present investigation showed that eosinophils display a characteristic granular appearance in cryo-sections and cytospins by differential interference contrast (DIC) imaging. This approach appeared to be more reliable for identification of these cells in situ than immunohistochemical labelling of eosinophil granule proteins. Moreover, combined with immunofluorescence microscopy DIC imaging facilitated three-colour immunofluorescence phenotyping of eosinophils.

Cell Count↗