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At least 199 records · Page 11Linked to original sources
PubMed1984

Microfilament distribution and adhesion patterns in cultured cells after glutaraldehyde-formaldehyde fixation.

To study the relationship between microfilament distribution and adhesion patterns in the same cultured cell, we have employed a simple glutaraldehyde-formaldehyde fixation technique followed by permeabilization of the cells in buffered Triton X-100. This method gives an excellent preservation of cellular morphology in general and of adhesion patterns in particular for examination with surface reflection interference microscopy. It also permits the concomitant use of the actin-specific fluorescent probe NBD-phallacidin to visualize the distribution of microfilaments.

Cell Adhesion↗
PubMedDate not supplied

[Changes in the dry weight of retinal pigment epithelium cells in the postnatal ontogeny of rats].

The dry weight of cytoplasm of individual cells of the retinal pigment epithelium was determined by interference microscopy in the rats (both in mononuclear and binuclear cells). During postnatal development the dry weight of cell cytoplasm is subject to fluctuations: it increases from the 1st till the 5th day, decreases between the 5th and 15th days and increases again between the 15th and 18th days. It is suggested that the decrease in dry weight of cytoplasm of the retinal pigment epithelium cells precedes the onset of phagocytizing by these cells of shed discs of the external rod segments.

Animals↗
PubMed1982

[Action of hypothyroidism on the metabolic maturation of the pyramidal neurons of the rat hippocampus].

Interference microscopy was used to measure dry mass of pyramidal neurones of hippocampal CA1 and CA3 areas in control and hypothyroid rats aged 14 and 21 days and 2 months. Hypothyrosis was induced in the newborn by intraperitoneal injection of methylthiouracil to the lactating female during the lactation period (for 1 month). Hypothyrosis caused a considerable retardation of the animals' growth. A significant decrease in he concentration of dry substances was detected only in the cytoplasm of Ca1 area neurones in the group of 2-month-old hypothyroid animals. The measurements have demonstrated that hypothyrosis gives rise to pronounced retardation of the neuronal build-up and accumulation of protein products in the cytoplasma of hippocampal pyramidal cells in all the animal groups examined. The size and dry weight of neuronal nuclei of both the hyppocampal areas substantially diminish in the group of 2-month-old hypothyroid animals.

Aging↗
PubMed1994

An indirect comparison of third-body wear in retrieved hydroxyapatite-coated, porous, and cemented femoral components.

The osteoconductive properties of hydroxyapatite (HA)-coated titanium implants are well documented, but eventual coating degradation may result in HA particles adjacent to the substrate, and if the particles were to migrate into the joint space then accelerated polyethylene wear might be expected. As an indirect indication of third-body wear, the authors used laser interference microscopy to measure and compare surface roughness on modular heads from 15 clinically retrieved HA-coated femoral components, with heads from 15 retrieved uncemented (porous) and 15 cemented implants. The results showed increased median surface roughness over initial manufacturer specifications in all groups, but the cobalt-chrome heads from the HA-coated group showed significantly less surface roughness and less deep scratches than the heads from either the porous or uncemented group. Three-body wear appears to be a common problem, but evidence available suggests that it is no more of a problem with HA-coated devices than porous or cemented.

Cementation↗
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↗