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PubMedDate not supplied

Trichothiodystrophy associated with urologic malformation and primary hypercalciuria.

Trichothiodystrophy (TTD) is a hair abnormality that may be associated with a large number of alterations affecting the skin phenotype and skin appendages, nervous system, eyes, bones, and immune, gonadal, and endocrine systems. We report the first case of TTD associated with a urologic malformation and primary hypercalciuria. Our patient had congenital ichthyosis, physical and mental retardation, and a dysmorphic facies associated with a complex urologic malformation and primary hypercalciuria. Characteristic features of his hair under microscopic examination (trichoschisis, alternating light and dark bands under polarizing microscopy, and a severely defective cuticle) and low sulfur content by radiographic microanalysis confirmed the diagnosis. We discuss the meaning of this new association in the spectrum of abnormalities related to TTD.

Abnormalities, Multiple↗

PubMed1988

Characterization and identification of substances isolated from dialyzer extracts.

The organic phase of dialyzer dried extracts obtained from Cuprophan hollow fiber and polyacrylonitrile AN 69 parallel-plate dialyzers, all sterilized by ethylene oxide, were submitted to light and polarized light microscopy, infrared (IR) spectrophotometry, and gas chromatography coupled with mass spectrometry. Colorless polygonal (approximately 5 X 20 micron) and needle-like (approximately 3 X 50 micron) crystals were found in great quantity on microscopy examination. IR spectrophotometry of the crystals embedded in potassium bromide disc showed specific spectra in the 1400-800 cm-1 wave number range and typical peaks on wave number assigned for hydroxy or amine (3420 cm-1), aromatic hydrogen (3060 cm-1), methyl, methylenic, or methenyl (2960-2860 cm-1), and carbonyl (1715 cm-1) groups can be demonstrated. Seven peaks were detected on gas chromatography of the organic solution containing crystals. Fatty acids and undefined compounds could originate from the dialyzer. Phtalates may leach from blood tubing, used in the rinsing procedure, and BHT is a stabilizer of ethyl ether used as solvent. These compounds could also originate from the dialyzer since phtalates are widely used as a plasticizer and BHT an antioxidant for various polymers.

Acrylic Resins↗

PubMed1992

Stress/strain characteristics of porcine mitral valve tissue: parallel versus perpendicular collagen orientation.

Mitral valve tissue was analyzed in uniaxial tension testing. Rectangular strips were excised from fresh, whole, porcine mitral valve leaflets, with the long axis in the following orientation: perpendicular to the annulus (posterior [PPERP] and anterior [APERP]), parallel to the annulus (posterior [PPAR] and anterior [CAPAR]), and parallel to the annulus and involving chordal insertions (anterior [MAPAR]). Basal and marginal chordae were also tested. These samples were tested in uniaxial tension (INSTRON Model 1000) at deformation rates of 5 and 10 mm/min, the load applied along the long axis of the strip. The specimens were preconditioned by cyclically loading from 0 to 4.0 g for five cycles, and then applying a final 50-g load. Whole excised porcine mitral valves were previously examined by small angle light scattering, polarized light microscopy, and routine histologic examination in order to ascertain the collagen fiber orientation throughout the valve. Groups tested in uniaxial tension with collagen fibers parallel to the applied stress are significantly stiffer than those with perpendicular fibers (p less than 0.001). Collagen fiber density is greater in the chordae than in the leaflets, and a corresponding increase in stiffness is demonstrated. This indicates that the mitral valve tissue behaves as a classic fiber reinforced composite, i.e., increasing mechanical stiffness (modulus) is related to density and direction of fibers. This information can be applied to the design of biosynthetic valve substitutes with a similar fiber reinforced composite structure.

Animals↗

PubMed1983

Clinical and histological characteristics of lyophilized allogenic dura mater in periodontal bony defects in humans.

This clinical and histological study investigated the use of lyophilized, allogenic dura mater (Lyodura) as a periodontal implant material in interdental bony defects (2-wall lesions) in humans. For 23 defects in 8 subjects a modified Widman flap was raised, curettage performed and the defects bridged with the implant. The same procedure, without Lyodura implantation, was performed on 23 contralateral teeth. By a standardized method, involving the use of a removable stent, the following clinical measurements were recorded after 24 and 48 weeks: the probing attachment level, the probing bone level, the probing pocket depth and the labial and interdental gingival recession. For the histological study 5 additional, interdental craters and 5 control defects were treated as in the clinical study. They were block-sectioned after 1, 2, 6, 12 and 24 weeks and processed in the usual manner for routine examination by light and polarization microscopy. From the clinical study it could be concluded that, in absolute values, only the experimental side showed a significant gain in probing attachment level and a greater reduction of the probing pocket depth. In percentage values the labial gingival recession was significantly lower and the bone formation significantly more pronounced on the experimental side. The histological examination showed that the implant remodelled completely without rejection phenomena. It was replaced gradually, after enzymatic breakdown, by the host's own collagen through the action of invading fibroblasts. Bone formation occurred along but never in the implant. The implant material seems to act as a barrier against epithelial downgrowth and infiltration of inflammatory cells.

Adult↗

PubMed2004

Periodontal repair in dogs: examiner reproducibility in the supraalveolar periodontal defect model.

BACKGROUND: Histometric assessments are routinely used to evaluate biologic events ascertained in histologic sections acquired from animal and human studies. The objective of this study was to evaluate the intra- and inter-examiner reproducibility of histometric assessments in the supraalveolar periodontal defect model. METHODS: Histometric analysis using incandescent and polarized light microscopy, an attached digital camera system, and a PC-based image analysis system including a custom program for the supraalveolar periodontal defect model was performed on histologic sections acquired from one jaw quadrant in each of 12 dogs. The animals had received an experimental protocol including implantation of a coral biomaterial and guided tissue regeneration (GTR) barrier devices, and were evaluated following a 4-week healing interval. Histometric parameters were recorded and repeated within a 3-month interval by two examiners following brief training. Intra- and inter-examiner reproducibility was assessed using the intra-class correlation coefficient (ICC). RESULTS: Most parameters showed high intra-examiner ICCs. Parameters including defect height, connective tissue repair, bone regeneration (height/area), formation of a junctional epithelium, positioning of the GTR device, ankylosis, root resorption, and defect area yielded an ICC> or 0..9. The ICCs for bone density and biomaterial density were somewhat lower (0.8 and 0.7, respectively). The inter-examiner reproducibility was somewhat lower compared to the intra-examiner reproducibility. Nevertheless, the ICCs were generally high (ICC range: 0.6-0.9). CONCLUSIONS: Histometric evaluations in the supraalveolar periodontal defect model yield highly reproducible results, in particular when a single examiner performs the histometric measurements, even when the examiner was exposed to limited training.

Animals↗

PubMed1978

Structural studies on calcium fluoride formation and uptake of fluoride in surface enamel in vitro.

The structural changes in human enamel during exposure to an acetate buffer, pH 4, containing 150 parts/10(6) fluoride have been studied using scanning electron microscopy and polarized light microscopy. After exposure for 2 h the enamel surface was covered by a fine-granular layer of calcium fluoride. The underlying enamel was highly eroded with an increased pore volume in the outer layer. Following an equilibration period of 3 months the uptake of fluoride in the apatite lattice had resulted in a highly mineralized, 100-micrometer-thick surface layer rich in fluoride covering a subsurface porous zone with an unchanged fluoride content. The deeply located, caries-like porous zone may have provided calcium and phosphate for saturation of the liquid.

Acetates↗

PubMed1983

Polarized light study of giant tubules in human and red deer coronal dentin.

Previously described giant tubules in human and red deer coronal dentin have been subjected to a study by polarized light microscopy. Structure of the giant tubules was similar in both species. The lumen of each tubule was bordered by a 5-15-micrometers-thick collagenous mantle in which the fibers were orientate parallel to its long axis. In a circular dentin area encompassing the mantle, the course of the collagen fibers might be characterized as a winding of fibers around the cylindrical mantle. This structure of the giant tubules conforms with that described earlier in the rudimentary maxillary canine of a red deer. Thus, such tubules do not represent a rare anomaly, but occur regularly in both human and red deer coronal dentin.

Animals↗

PubMed1987

Identification of cellulose fibers in oral biopsies.

Oral biopsies comprising five periapical cysts, three cases of exuberant granulation tissue in extraction sockets and one case of a mandibular radiopaque structure, all displaying material consistent with cellulose fibers on routine histologic examination, were subjected to histochemical, polarization, fluorescence and scanning electron microscopical, energy dispersive X-ray and chemical investigations. Routine screening of periapical lesions with polarization microscopy and identification of possible cellulose fibers with Calcofluor White is advocated. Further, attention is drawn to endodontic paper point material as an etiologic factor in postendodontic periapical inflammatory processes.

Adolescent↗

PubMed1990

Column-like structures following the course of tubules in human dentin.

Sections, 60-180 microns thick, of permanent teeth, intact or with minor fillings, were cut parallel or transversal to the course of the dentinal tubules. Some teeth were demineralized, embedded in paraffin wax, cut in series, and stained with toluidine blue pH 5.6, hematoxylin-eosin, or PAS. Altogether, sections of 90 teeth were examined by ordinary and polarized light microscopy and contact microradiography. Alternating light and dark bands, usually 8-30 microns wide, extended from the pulpal border along the course of the tubules, gradually increasing in width, fading in the mantle dentin. Cross-sectioned bands appeared as dark and light "discs". This was the background for the term "columns". In the dark columns, usually exhibiting crowding of tubules, the intertubular dentin was dark and radiolucent; in the light columns, light and radiopaque. Dark columns contained a high amount of GAGs, assumed to have exerted an inhibitory effect on their mineralization. The columns probably represent structural elements in the architecture of dentin, possibly offering resistance against mechanical stress. It was suggested that the columns might depict functional differences in the matrix secretion and mineralization capacities of odontoblasts.

Adult↗

PubMed1993

Reactivity of young and old human enamel to demineralization.

The aim of this study was to determine the susceptibility of newly erupted and old permanent teeth to artificial, caries-like attacks. Two groups of caries-free teeth were used. Group 1 consisted of 38 teeth extracted for orthodontic reasons (9-12-yr-old children); group 2, of 40 teeth extracted for periodontal reasons (45-65-yr-old patients). After thorough cleaning, a test window was isolated on the incisal two-thirds of the buccal surface. After demineralization with 6% HEC gel at pH 4.9 for 8 days, longitudinal ground sections were prepared for imbibition studies in polarized light and for secondary ion mass spectrometry (SIMS). In the young teeth, the lesions appeared to be uniform in their extension in the enamel, whereas the old teeth showed less marked and thinner surface zones and greater depth of the positively birefringent body of the lesion. Polarized light microscopy and SIMS data support the hypothesis that there are different enamel pathways in the initiation of the natural carious process.

Age Factors↗

PubMed2005

Fluoride release and secondary caries inhibition by adhesive systems on root dentine.

This study tested the fluoride-release rate and the root caries inhibitory effect of dental adhesives. In phase 1, the fluoride released from samples (n = 5) of the adhesives A (Optibond Solo), B (One-up Bond F), C (Prime & Bond NT), D (Tenure Quick), and also of the controls [+] (glass-ionomer cement) and [-] (non-fluoride releasing adhesive), was quantified on a daily basis during a pH-cycling, caries-simulating phenomenon. In phase 2, restorations were made in bovine root dentine slabs (n = 16) with the same adhesives associated with a non-fluoridated composite. Control [+] restorations were made entirely with glass-ionomer cement. Specimens were thermocycled and submitted to the pH-cycling regimen. Demineralization areas and the presence of the wall lesion (WL) and the inhibition zone (IZ) were determined by polarizing light microscopy in dentine adjacent to the restoration. The highest concentration of fluoride was released by the control [+]; adhesives A, B and C, also released fluoride. No detectable amount of fluoride was released by D or [-]. Smaller areas of demineralization were found with control [+], whereas the demineralization areas of adhesives A-D and [-] did not differ from each other. No WL was detected, and higher percentages of IZ were recorded to [+] and to adhesive A. Although some dental adhesives were able to release fluoride, they could not inhibit secondary caries development as well as the glass-ionomer cement.

Animals↗

PubMed1994

Local delivery of prostaglandin E1 induces periodontal regeneration in adult dogs.

Formation of cementum, alveolar bone and periodontal ligament was produced in 18 sites on buccal surfaces of mandibular premolars and molars of 11 adult dogs near to sites of local delivery of prostaglandin E1 (PGE) for three weeks. Mineralizing bone and cementum were labelled with fluorescent dyes and polarizing microscopy showed periodontal ligament fibers between these new mineralized tissues. These observations extend recent demonstrations that local application of PGE causes formation of new bone on the mandible and suggest the potential for predictable, site-directed periodontal regeneration.

Alprostadil↗

PubMed2004

The efficacy of a fluoride varnish in reducing enamel demineralization adjacent to orthodontic brackets: an in vitro study.

OBJECTIVES: To test the hypothesis that fluoride varnish is effective in reducing demineralization (white spot) lesions adjacent to bonded orthodontic brackets. DESIGN: Two similar samples of extracted bovine incisors, with bonded orthodontic brackets, were separated into an experimental group (fluoride varnish was applied) and control group (no fluoride varnish) to examine the preventive effects of fluoride varnish. SETTING AND SAMPLE POPULATION: The dental clinic of the State University of Maringá--UEM (Maringá, Paraná, Brazil). Thirty-eight extracted bovine incisors with bonded orthodontic brackets. EXPERIMENTAL VARIABLE: Fluoride varnish was applied topically to half of the sample of extracted bovine teeth. No varnish was applied to the other half. OUTCOME MEASURE: The depths of enamel demineralization (white spot) lesions were measured from polarized light microscopy images using image analysis software. RESULTS: The teeth in both the experimental and control groups had been exposed to a cariogenic environment twice a day for 35 days. Those teeth that had been treated with two applications of fluoride varnish (one at the outset and another 15 days later) demonstrated about 38% less mean lesion depth than teeth where no varnish had been applied. CONCLUSION: Orthodontists may wish to consider the application of fluoride varnish during fixed orthodontic therapy to help reduce the development of enamel white spot lesions.

Animals↗

PubMed2006

A 19-year-old male with generalized seizures, unconsciousness and a deviation of gaze.

Light chain deposition disease (LCDD) is a form of monoclonal immunoglobulin deposition diseases (MIDD) which in contrast to light-chain derived (AL) amyloidosis is characterized by non-congophilic, non-fibrillary monoclonal protein deposits. Systemic organ deposits are common with the kidney being a major target organ. A clonal lymphoplasmocytic proliferation, e.g. plasmacytoma, is present in the majority of cases. Here we report on a 19-year-old male who presented with generalized seizures and an enhancing white matter lesion on MRI scans. A stereotactic brain biopsy revealed a low-grade B cell lymphoma with plasmacellular differentiation as well as lambda light chain deposits without birefringence under polarized microscopy. No systemic lymphoma manifestations or systemic light chain deposits were found, nor was a monoclonal gammopathy detectable in serum and urine. After systemic chemotherapy with three courses high-dose methotrexate the size of the lesion and the condition of the patient have remained stable for 24 months now. This is the first description of cerebral LCDD developing without systemic disease in conjunction with the diagnosis of a cerebral low-grade B cell lymphoma. We present the clinical, laboratory and radiological findings and discuss the pathogenesis of this unusual LCDD manifestation.

Adult↗

PubMedDate not supplied

Effect of 2% plain and fluoridated milk on root surface caries in vitro.

The caries-protective effect of milk and fluoridated milk on enamel has been reported; however, few data are available concerning the role of milk and/or fluoridated milk on root surfaces. The aim of this study was to compare the effect of plain and fluoridated milk on root surface caries. Artificial root surface lesions were created, sectioned and analyzed using polarized light microscopy (PLM) and microradiography (MRG). The sections were covered except for the original surface and assigned to a treatment group. The samples were immersed in 2% plain milk or fluoridated milk for 40 hours and re-evaluated. Changes were measured and mean differences were compared with an unpaired t-test. Both techniques revealed a reduction in lesion depth for each milk group; however, a significantly greater reduction (p<0.05) was observed with the fluoridated milk. These results suggest that fluoridated milk may have a beneficial effect on the remineralization of root surface caries.

Animals↗

PubMed1989

Liquid crystalline phases of sonicated type I collagen.

The assembly properties of concentrated solutions of type I collagen molecules are compared before and after a 5-min sonication, breaking the 300-nm triple helices into short segments of about 20 nm, with a strong polydispersity. The collagen concentration of these solutions, sonicated or not, was increased up to 100 mg/ml by slow evaporation of the solvent. Whereas the non-sonicated solutions remain isotropic, the sonicated solutions transform after a few hours into a twisted liquid crystalline phase, well recognizable in polarizing microscopy. The evidence of a twisted assembly of collagen triple helices in vitro is new and relevant in a biological context since it was reported in various collagen matrices.

Animals↗

PubMed2000

Studies of dental root surface caries. 1: Comparison of natural and artificial root caries lesions.

Qualitative polarized light microscopy and cross-sectional microhardness testing profiles were used to compare artificial root caries lesions with those naturally present in extracted human teeth. The artificial lesions were produced by immersion of roots with exposed windows in chemical buffers of acetate and lactate with no added enzymes or bacteria. The three buffer systems used produced lesions with the range of histological characteristics of natural lesions. These included a 'body' or 'surface' zone of the lesion when viewed in water, and a 'frontal' zone of reverse birefringence when viewed in quinoline. The 'frontal' zone was noted to first develop after three days of immersion in acetate buffer. Advanced natural lesions exhibited a wide, diffuse, advancing front, which was similar to that produced by 28-60 day lesions in acetate. Microhardness profiles of natural lesions could all be matched by one or more of the artificial lesions. The demineralizing process was seen to reduce mineral content across the lesion from 45 per cent in normal dentine to between 15 and 25 per cent.

Acetic Acid↗

PubMed2000

Studies of dental root surface caries. 2: The role of cementum in root surface caries.

Artificial caries lesions were produced in roots of teeth using an acetate buffer system, when the layer of cementum was either normal in thickness, excessively thickened by hypercementosis, or had been removed completely. The rates of lesion progression were measured in each case using polarized light microscopy to measure lesion depth. Analysis of calcium (Ca) and phosphorus (P) loss during the demineralizing process was carried out. The removal of cementum was found to significantly increase the initial rate of penetration of the lesion into the root, although this rate progressively reduced to a level consistent with that found in normal roots after seven days of demineralization. The overall depth remained consistently greater than that observed in normal roots, or when lesions were produced entirely within hyperplastic cementum. Chemical analysis also showed removal of cementum resulted in an initial doubling of the Ca and P lost from the root surface. Prior direct exposure of segments of normal roots to the oral environment was found not to significantly alter the rate of artificial lesion progression, in comparison with that in the originally protected segment of the root surface. It was concluded that an intact cementum layer has the intrinsic ability to protect the underlying dentine of exposed tooth roots against acidic demineralization and that prior exposure to the oral environment does not significantly alter this ability.

Calcium↗