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D E Steflik

Publications and source records attributed to D E Steflik.

At least 73 records · Page 4Linked to original sources
PubMed1984

Surface changes in rat gastric mucosa induced by sodium fluoride: a scanning electron microscopic study.

This paper describes the ultrastructural, topographical changes seen in rat gastric mucosa following application of 0.1 N HCl or 1, 10 or 50 mM NaF in 0.1 N HCl to the stomach. No morphological differences were noticed between the 0.1 N HCl (control) and 1 mM NaF in 0.1 N HCl specimens. Ten milliomolar NaF in 0.1 N HCl produced some desquamation of surface mucous epithelial cells while 50 mM NaF produced extensive damage to cells surrounding the gastric gland openings (foveolae) as well as interfoveolar cell loss.

Animals↗
PubMed1984

Scanning electron microscopy of plasma etched implant specimens.

Following surface etching of previously processed plastic embedded specimens containing hard and soft tissues and implanted biomaterials with oxygen plasma, the fine structure of the tissues can be examined by scanning electron microscopy. One micrometer plastic orientation sections (with the implant removed in processing) and 110 microns histological sections (with the implant in situ) were examined. Direct comparison can be made between the scanning and histological observations. An examination in situ of oral tissues next to the biomaterial was also made, care being taken to minimize damage to the specimen. The fine structure of intracellular organelles was examined in detail. The method allows consecutive gathering of histological and ultrastructural data from the same plastic embedded specimen.

Animals↗
PubMed1984

The biomaterial-tissue interface: a morphological study utilizing conventional and alternative ultrastructural modalities.

The interface between oral tissues and ceramic endosteal dental implants was investigated in 36 experimental cases in dog jaws. Conventional electron microscopic modalities showed those tissues adjacent to the implants to be viable with no adverse cellular response to the biomaterial. A procedure to retrieve additional ultrastructural data from previously processed biological material was developed to expand upon these data. This included surface-etching with oxygen plasma of routinely processed electron microscopy specimens and formalin fixed histological specimens for scanning electron microscopy (SEM) study; and, cryofracturing of similar histological specimens for additional transmission electron microscopic (TEM) analysis. Results from these alternative protocols supported our observations from conventional studies of the direct association of bone and epithelia to the implant. In addition, they demonstrated a unique portrayal of the epithelial maturation patterns. Further, this alternative TEM method showed excellent retention of cellular integrity and demonstrated a hemidesmosomal-external basal lamina attachment apparatus at the junctional epithelial-implant interface. This latter composite attachment structure was not retained in our previous conventional microdissection procedures. Thus, the interface between oral tissues and the single crystal sapphire endosteal dental implant could be elucidated by these protocols.

Animals↗
PubMed1983

Correlated TEM, SEM, and histological observations of filiform papillae of the cow tongue.

The ultrastructural and histological characteristics of the filiform papillae of the cow tongue are described. These large, conical papillae display a fully keratinized external projection, which demonstrates a dominant hard keratin core partially ensheathed by soft keratin. This biostructure differentiates from a dominant posterior cell line, leading to the hard keratin core, and a thinner anterior cell line which, with contributions from an interpapillary cell line, appears responsible for an attenuating sheath of soft keratin around the hard keratin core. The hard keratin cell line differentiates from cells devoid of keratohyalin granules (KHG), which are rich in thick bundles of tonofilaments. The soft keratin cell line differentiates from cells containing both eosinophil and basophil KHG and dispersed tonofilaments. The bovine filiform papilla also appears similar in biostructure to the mammalian hair shaft and the 'filiform hairs' of the rat penis.

Animals↗
PubMed1983

A statistical analysis of the clinical response to the single-crystal sapphire endosseous dental implant in dog jaws.

A statistical analysis was carried out on the clinical evaluatory data gathered from a two-year longitudinal study of the single-crystal sapphire endosteal dental implant in dog jaws. Statistically, the implants behaved either better than control molars (clinically), or in a manner similar to control molars. These data suggest an excellent prognosis for the single-crystal sapphire dental implant.

Aluminum Oxide↗
PubMed1982

Simultaneous histological preparation of bone, soft tissue and implanted biomaterials for light microscopic observations.

Block specimens of formalin fixed bone, soft tissue and endosseous implanted biomaterials can be successfully embedded in polymethyl methacrylate by employing vacuum desiccation during the dehydration steps and refrigeration during the infiltration step. One-hundred-micrometer histological sections can be obtained from the cured polymethyl methacrylate blocks by cutting with a low concentration diamond wafering blade on a Buehler Isomet Circular Low Speed Saw using Buehler Isocut fluid. The sections can be readily stained and details of individual cells studied by light microscopy, thus allowing interpretation of the relationship between biomaterial and surrounding tissues. The advantage of this method is that it allows observations of the entire specimen in situ. The details of the procedure are presented.

Animals↗
PubMed1981

Effects of retinoic acid on the differentiation of hamster cheek pouch epithelium grown in vitro.

Recently our laboratories have successfully attained preferential epithelial outgrowths from hamster cheek pouch explants. This has allowed us to systematically analyze oral epithelial cell differentiation as weel las examine the modulatory effects of various physiologic and pharmacologic agents in this epithelial cell system. The objective of the current investigation was to study the effects of various doses of retinoic acid (RA) on the epithelial outgrowths of hamster cheek pouch. Light microscopic observations employing colcemid treatment indicated that 10 IU/ml RA enhanced mitotic activity of the epithelium up to 25%. Scanning electron microscopic observations of control cultures showed flat, polyhedral epithelial cells containing thin long microvilli connecting the adjacent cells. In contrast, cultures treated with 10 IU/ml RA showed round or spherical cells exhibiting short of medium sized thicker microvilli. These were covered with a fuzzy appearing layer probably representing glycocalyx. Many bleb-like formation were also observed. Transmission electron microscopic examination of the control cultures showed the presence of tonofilaments and desmosomes, characteristic components of the keratinizing epithelia. In contrast, the RA treated cultures included cells which apparently were either devoid of tonofilaments or contained few fine filaments and small intercellular functions. In addition many vacuoles as well as variable numbers of electron-dense and electron-lucent granules were observed. Thus, it appears that RA inhibited keratinization and altered the differentiation pattern of keratinization and altered the differentiation pattern of keratinizing epithelium.

Animals↗
PubMed1980

A correlative light microscopic, scanning and transmission electron microscopic study of the dog tongue fiiform papillae.

Recent studies in our laboratories have suggested that the epithelial cells of the dog tongue filiform papillae are organized into clearly delineated epithelial cell columns within the papillae. However, the contributions of these epithelial cell columns to the surface morphology of the dog papillae was unknown. Therefore, the objective of this investigation was to conduct a correlative scanning electron microscopic (SEM), transmission electron microscopic (TEM) and light microscopic (LM) examination of these epithelial cell columns in dog filiform papillae to study their contribution to tongue surface morphology. By scanning electron microscopy the numerous conical filiform papillae observed on the anterior two-thirds of the dog tongue were curved posteriorly. In addition to these primary papillary projections, the papillae exhibited secondary conical projections. A number of conical tertiary projections were also located anteriorly at the base of the papillae. Correlative histologic studies revealed anterior and posterior epithelial cell columns for the primary projections, lateral columns for the secondary projections and 5-7 smaller cell columns corresponding to tertiary projections seen by SEM. Thus, it appears that there is a complex organization of the proliferating and differentiating epithelial cells in dog filiform papillae. These epithelial cell columns exist as distinct units and correspond to the various surface projections.

Animals↗
PubMedDate not supplied

Retrospective review of osteoarticular infections in a pediatric sickle cell age group.

Patients with sickle cell disease have been documented to be particularly susceptible to osteoarticular infections. Controversy exists concerning the bacteriology, etiology, and clinical presentation in differentiating osteoarticular infections from bone infarct. We retrospectively reviewed all cases from our institution over the past 22 years of osteoarticular infections in children who carry the diagnosis of sickle cell disease. Two thousand consecutive patient charts of children enrolled in the Pediatric Sickle Cell Clinic of our institution between 1973 and 1995 were evaluated. There were 14 cases of bone or joint infections (10 osteomyelitis, four septic arthritis). There was one case of multicentric osteomyelitis and one case of meningitis complicating the septic arthritis. There were nine male and five female patients with ages ranging from 6 months to 17 years (mean, 8.0). All patients were noted to have hemoglobin SS. The predominant presenting symptoms were pain (79% of cases) and swelling (71% of cases). The most frequent physical findings were fever >38.2 degrees C (71% of cases) and tenderness (86% of cases). Ninety-three percent of the children had a white blood count exceeding 15,000/mm3 (range, 7,900-32,300). Westergren sedimentation rates ranged from 14 to 89 mm/h with 93% of the children exceeding the normal value in our hospital. Cultures were positive in 75% of tissue biopsies, 58% of the blood cultures, and 70% of the bone or joint aspirates. The most common offending organism found in osteomyelitis was Salmonella (eight of 10 cases); however, no predominant organism found was identified in cases of septic arthritis. Radiographs and bone scans were of limited value in the differential diagnosis between osteoarticular infections and bone infarction. Early diagnosis and treatment of osteoarticular infections is key to satisfactory outcome. This study suggests that an ill-appearing patient with a fever >38.2 degrees C, pain, and swelling should prompt the physician to aspirate or biopsy the area and not rely on diagnostic studies that we found to be unreliable.

Adolescent↗
PubMedDate not supplied

Histologic evaluation of the periodontium of abutment teeth in combination implant/tooth fixed partial denture.

The histologic response of the periodontal tissues of teeth rigidly joined to implants with a fixed partial denture was evaluated using light microscopy. The fourth premolar of a dog was connected to implants placed in the first and second premolar position with a fixed partial denture. The restored teeth were under function for periods of 6, 12, 18, and 24 months, with unrestored fourth premolars as controls. The histology of the periodontal ligament on the fourth premolar was found to be similar in the control and the restored teeth. The periodontal tissues contained a minimal amount of inflammatory cell infiltrate. The crestal bone was cortical in nature, showing no periodontal breakdown. The orientation of the periodontal fibers was easily determined, indicating that minimal remodeling had taken place. The number and morphology of the blood vessels were also similar in the control and the treated teeth. The lack of inflammation and stability of the periodontal tissue suggested that the use of combination implant-to-natural-teeth restorations with rigid joints in this animal model does not result in deleterious effects on the periodontal tissues and that the forces placed on the tissues are within the remodeling capabilities of the teeth.

Animals↗
PubMedDate not supplied

Histologic and histomorphometric comparison of immediately placed hydroxyapatite-coated and titanium plasma-sprayed implants: a pilot study in dogs.

The purpose of this pilot study was to make a histologic and histomorphometric comparison of hydroxyapatite-(HA) coated and titanium plasma-sprayed (TPS) root-form implants that were placed in 2 mongrel dogs immediately after extraction of mandibular premolars. After 8 weeks of healing, the implant-containing segments of the mandible were removed en bloc and bone blocks including implants were sectioned. Histologic and histomorphometric analyses were performed by evaluating bone sections. The mean bone contact percentage of HA-coated implants was 61.84 +/- 7.84%, with a range of 52.09% to 75.7%, and the mean bone contact percentage of TPS implants was 51.35 +/- 12.1%, with a range of 30.1% to 70.6%. This pilot study suggests that HA-coated implants placed into fresh extraction sockets can achieve better bone contact than TPS implants, but there was evidence that the surface of the HA layer can be resorbed, so long-term stability of HA coatings in immediate implantation must be investigated.

Animals↗
PubMedDate not supplied

Clinical and histologic findings of the dentition in a hypopituitary patient: report of case.

Idiopathic hypopituitarism is associated with delayed dental eruption as well as delayed growth of the dentofacial complex. Both maxillary and (especially) mandibular growth can be affected. The clinical dental findings and histologic findings related to enamel maturation in the permanent dentition of a teenaged male with a hypopituitary condition are described.

Adolescent↗