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At least 91 records · Page 5Linked to original sources
PubMed1999

Retrieval analyses of implanted biomaterials: light microscopic and scanning electron microscopic analyses of implants retrieved from humans.

We report analyses obtained from 135 implant cases retrieved from humans and submitted to the American Academy of Implant Dentistry Research Foundation--Medical College of Georgia Implant Retrieval Center. The undecalcified samples were embedded in polymethyl-methacrylate and examined with scanning electron microscopy and with routine light via polarized or Nomarski microscopy. Cases included both orthopedic and dental implants as well as entire mandibles obtained at autopsy. Significant numbers of submitted implants had substantial amounts of adhered bone, which permitted evaluation of human bone remodeling to osseointegrated implants. These implants failed because of implant fracture. As has been observed in animal studies, an interdigitating canaliculi network provided communication between interfacial osteocytes and osteocytes deeper within the remodeled osteonal and trabecular bone. Significant numbers of osseointegrated fractured hydroxyapatite-coated dental implants demonstrated the adequate serviceability of these implants prior to biomaterial fracture. In contrast, the hydroxyapatite coating was dissociated from retrieved orthopedic implants, leading to extensive cup loosening and case failure. Caution is advised for the use of hydroxyapatite-coated acetabular implants. This study therefore underscores the need for evaluation of failed human dental and orthopedic implants. Correlations can be drawn between human retrieval and experimental animal studies.

Aged↗
PubMed2001

Light microscopic and scanning electron microscopic retrieval analyses of implanted biomaterials retrieved from humans and experimental animals.

This paper reports analysis obtained from 200 implant cases retrieved from humans and submitted to the American Academy of Implant Dentistry Research Foundation, Medical College of Georgia implant retrieval center. The samples that were not decalcified were embedded in polymethylmethacrylate and examined with scanning electron microscopy and routine light, polarized, or Nomarski microscopy. Cases included both orthopedic and dental implants, as well as entire mandibles and portions of maxillae obtained at autopsy. A significant number of submitted implants had substantial amounts of adhered bone, which permitted evaluation of human bone remodeling to osseointegrated implants. These implants failed because of implant fracture. As was observed with animal studies, healthy bone supported these implants, with the bone containing an interdigitating canaliculi network that provided communication between interfacial osteocytes and osteocytes deeper within the remodeled osteonal and trabecular bone. Early dental implants containing a coating of beads showed a connective tissue interface, which corresponded to the bead surface of specific orthopedic implants that underwent some degree of micromovement. This is in contrast with the excellent response reported for successful contemporary beaded implants. Significant numbers of osseointegrated fractured hydroxyapatite (HA)-coated dental implants demonstrated the adequate serviceability of these implants before biomaterial fracture. In contrast, the HA coating was dissociated from retrieved orthopedic implants, leading to extensive cup loosening and case failure. This study, therefore, underscores the need for evaluation of failed human dental and orthopedic implants. Correlations can be drawn between human retrieval and experimental animal studies.

Aluminum Oxide↗
PubMed1992

[Comparative light microscopic, scanning-electron microscopic and electron microscopic studies of the effect of experimental interventions by surgical scalpel, electrocautery and CO2-laser beam in the oral cavity].

Tissue effect interventions by means of surgical scalpel, elecrtokauter and CO2-laser ray in the mouth cavity of 20 white rats has been examined. According to their light microscopical examinations both the laser and the electrokauter caused thermal injuries taking place in typical zones while by the scalpel the cut surface in rendered ragged. The band-width of the thermoinjury caused by the kauter is a multiple of that caused by the laser. It has been proved by means of scanning electronmicroscopical examinations that interventions by means of laser result in sharp wound borders, the wounds cut by means of kauter are characterised by the presence of a great number of carbonized specks while by means of the scalpel a mechanical tear of the tissues is brought about. By means of electronmicroscopical examination the characteristics of the typical thermoinjured zones are described. It has been established that in the case of laser the injury of the ultra-structure extends to 400 microns while in case of electrokauter it reaches a width of 1500 microns. The excellent haemostatic effect brought about by the thermoeffect by means of the laser, in contrast to the broad thermoinjured zone caused by the kauter, is obtained at a very mild thermoinjury.

Animals↗
PubMed1996

[Observations of Setaria equina (Nematoda: Setariidae) with the optical microscope and scanning electron microscope].

Adults of S. equina (Spirurida, Setariidae), 1 male and 2 females, collected from vaginal sac of stallion, were studied by soanning electron microscopy (SEM). The amphids, cephalic and cervical papillae, peribuccal ring, fine transverse bands and bosses of the cuticle, as well as caudal papillae were visualized clearly at this examination. The results of the present survey contribute towards the identification of S. equina, improve the definition of the characters which are demonstrated by common light microscopy and give the exact number of male caudal papillae including the lateral cloacal right papilla considered as a probable anomaly in literature.

Animals↗
PubMed1984

Biological, microscopic and scanning electron microscopic investigations of the effects of postinor /d-norgestrel/ in rabbits.

The contraceptive effect of d-norgestrel given immediately after copulation in various quantities was investigated in rabbits. It was established that the effect is dose-dependent. A correlation was found between the amount of dose administered and the changes taking place on the surface of endometrium. It can be suggested that d-norgestrel alters the surface of the endometrium to such an extent that nidation is unable to take place; therefore, it can be used for postcoital contraception at any time.

Animals↗
PubMed1981

Benign, borderline and malignant serous cystadenomas of the ovary. A transmission and scanning electron microscopical study.

In this study benign, malignant and borderline types of ovarian cystadenomas were studied by different morphological, transmission electron microscopical and scanning electron microscopical methods. The main cell type, the tubal cell, contained numerous microvilli projecting into the lumen, some cells also possessed cilia in addition to microvilli. Infrequently endometrial like cells were found with branched cilia intermixed with microvillous projections similar to that of the endometrium. Endocervical-like cells, very uncommon, evidenced numerous cytoplasmic projections extending into the lumen, arranged in a wavelike pattern. The surface structures were well developed in benign tumors, in borderline tumors focal denuded areas with histologically atypias were seen and in malignant ones the surface cells were devoid of specialised structures. The results also support a metaplastic origin from ovarian surface epithelium for these tumors.

Cilia↗
PubMed1982

Sjögren-Larsson syndrome: microscopic and scanning electron microscopic findings in replicas of the skin.

Replicas of the skin below the cubital fossa were made in 29 SLS patients with an age range of 8 days to 69 years. The skin surface patterns differed from those in healthy controls. The papillomatosis observed in most SLS replicas seemed to appear during the first year or years of life and to increase in some patients with increasing age, but seemed to diminish again in middle-aged and older SLS patients. Other common features were the occurrence of longitudinal and transverse furrows. All these findings in SLS patients could, at least in part, represent an exaggeration of the normal skin surface pattern. The use of replicas for diagnostic purposes is commented on.

Adolescent↗
PubMed1990

[The blood vessel supply of the testis in Pekin drakes (Anas platyrhynchos L.). Macroscopic, light microscopic and scanning electron microscopic studies].

Testes of Pekin ducks were macerated following injection with plastic at the period of maximal spermatogenesis which occurs during spring. The right and left A. testicularis arise from the A. renalis cranialis. The right testis is additionally supplied by an irregularly occurring A. testicularis accessoria. After penetrating the testicular capsule the arteries run to the centre of the testis and terminate as branching Aa. radiatae centrifugales. The seminiferous tubules are surrounded by intertubular and peritubular capillaries forming a rope-ladder-like system. Venules and veins run peripherally to enter the vein converge into the testicular hilus, and unite to form 2 Vv. testiculares which empty into the V. cava caudalis. Regulation of testicular blood supply is achieved by throttle devices depending on the avian seasonal cycle. The coiled and step-like course of the vessels results in a sufficient contact between blood and seminiferous tubules. Testicular veins surrounding the arteries might be an equivalent of the steroid transfer mechanism in the mammalian spermatic cord.

Animals↗
PubMed1982

Light microscopic and scanning electron microscopic findings on intravenous polyurethane catheters.

Tips of two different types of unused and used intravenous polyurethane catheters as well as heads of the corresponding needles for venipuncture, artificially cut surfaces and longitudinally cut parts were either directly mounted on stubs or previously fixed in 1% phosphate buffered glutaraldehyde, postfixed in 1% phosphate buffered osmiumtetroxyde (pH 7.4), dehydrated with acidified 2,2-Dimethoxypropane, dried in a critical point drying apparatus using CO2, mounted with silver paint on stubs and sputter coated with 15 nm gold. In general, the surface of polyurethane catheters is smoother than that of catheters manufactured out of other materials. Distance marks, when placed on the surface and parts of the catheter wall, containing radio-opaque admixtures show a very irregular arranged structure. It could be demonstrated, that these parts of the catheter wall as well as roughnesses, caused by the manufacturing process, are much more favourable for adhesion of formed elements of the blood and bacteria or spores than other areas of the wall. In addition occasionally extensive fibrin layers and contamination of the surfaces by denaturated plasma proteins were observed. For better compatibility and for prevention of endothelial lesions some advice is given to the manufacturers and the medical staff.

Bacteria↗
PubMed2001

Early anchoring collagen fibers at the bone-tendon interface are conducted by woven bone formation: light microscope and scanning electron microscope observation using a canine model.

To clarify the early process of recovery at the bone-tendon interface, we used light microscopy and SEM to examine the process of anchoring of collagen fibers to bone in a canine model. At two weeks, tendon, scar tissue, woven bone and lamellar bone were present at the insertion site. SEM revealed anchoring of collagen fibril bundles of the scar to the woven bone. By 4 weeks, the number of anchoring fibers had increased and a parallel arrangement of fibers was observed. SEM demonstrated deep penetration of fibers into the woven bone layer. In addition, the fibers were observed to project into and intermingle with the scar tissue. By 6 weeks, the anchoring fibers had developed fully and were distributed densely over the interface. SEM also revealed that the collagen fibril bundles in the scar tissue had connected with the collagen fibrils of the woven bone by way of the anchoring bundles. The woven bone was identifiable throughout the early stages of recovery as the interface between soft tissue and hard tissue. Throughout all experimental periods, no staining was observed at the interface of the tendon and bone by Saffranin-O. The formation of woven bone was important during early recovery of the tendon-bone interface prior to the completion of fibrocartilage-mediated insertion.

Animals↗
PubMed1977

The vascularization of the neural stalk and the pars nervosa of the hypophysis in the toad, Bufo bufo (L.) (amphibia, anura). A comparative light microscopical and scanning electron microscopical study.

The angioarchitecture of the neural stalk and the encephaloposthypophysial portal system of the hypophysis of the toad, Bufo bufo (L.), was studied using three different methods. The neural stalk is mainly supplied by branches of the arteria infundibularis superficialis which form a widemeshed vascular network. Dorsally this network continues into the plexus of the pars nervosa. The vascularization of the pars nervosa is made up of the encephalo-posthypophysial portal system. This portal system consists of a hypothalamic branch (=portion), a mesencephalic and a mesencephalicbulbar branch (=portion). The hypothalamic branch was found to drain the pars ventralis of the tuber cinereum as well as more dorsal regions of the diencephalon. The mesencephalic-bulbar trunk enters the hypothalamic branch. The resulting common stem of the encephalo-posthypophysial portal vein the curves around the retroinfundibular communicating artery, crosses its ventral side and runs caudally. The secondary capillary plexus of the pars nervosa is characterized by well defined capillary plexus of the pars nervosa is characterized by well defined capillary networks which are located at the periphery of the parenchyma of the pars nervosa, thus forming a rostral, dorsal and ventro-caudal net. The central region of the parenchyma of the pars nervosa is supplied only by main branches of the encephalo-postpophysial portal vein. The venous drainage of the pars nervosa is via the vena hypophysea transversa.

Animals↗