Diagnostic capabilities of fractal dimension and mandibular cortical width to identify men and women with decreased bone mineral density.

UNLABELLED: Dental panoramic radiographs could be used to screen for osteopenia. We found the fractal dimension to be a good discriminator of osteopenia in both men and women but that the mandibular cortical width (MCW) did not perform as well in men. The fractal dimension may be a valid screening tool. INTRODUCTION: The aim of this study was to assess the diagnostic capability of the fractal dimension and MCW measured from dental panoramic radiographs in identifying men and women with decreased bone mineral density (BMD). METHODS: The MCW and fractal dimension were measured from dental panoramic radiographs as surrogates for BMD. These measures were then compared to the results from dual-energy X-ray absorptiometry (DXA) performed for clinical purposes. A total of 56 subjects with the panoramic radiograph taken within 6 months of the DXA exam were used in the analysis for this study. RESULTS: The area under the curve of the fractal dimension for identifying low BMD (T-score <-1.0) was 0.81 (0.67, 0.95) and 0.78 (0.49, 1.00) for men and women, respectively. For the MCW, the area under the curve was found to be 0.53 (0.34, 0.72) and 0.80 (0.58, 1.00) for men and women, respectively. CONCLUSIONS: In this largely male study population, the fractal dimension was found to be a good discriminator of low BMD in both men and women. The MCW did not perform as well in men.

Nerve growth factor receptor (p75)-immunoreactivity in the normal adult feline trigeminal system and following retrogasserian rhizotomy.

The 75 kDa protein nerve growth factor receptor [NGFr(p75)] is a neurotrophin receptor that is able to bind different members of the neurotrophin family of molecules implicated in affecting neuronal survival. Here we describe the light microscopic distribution of NGFr(p75)-immunoreactivity (IR) within the feline trigeminal brainstem sensory nuclear complex and trigeminal ganglion of normal adult subjects and in subjects 10 and 30 days following retrogasserian rhizotomy. Within the trigeminal ganglion of normal subjects, numerous fibers and most of the neuronal cell bodies showed NGFr(p75)-IR that varied in intensity, while cells and fibers with NGFr(p75)-IR were less numerous within the mesencephalic trigeminal nucleus. Within the main sensory and spinal trigeminal nuclei, NGFr(p75)-IR formed a reproducible pattern that varied between the different subnuclei. The NGFr(p75)-IR consisted both of dense pockets and a low level NGFr(p75)-IR that was selective to the trigeminal neuropil. Following rhizotomy, most of the NGFr(p75)-IR was lost from the main sensory and spinal trigeminal nuclei, except in regions where the upper cervical roots and cranial nerves VII, IX, and X project. In contrast, examination of the central root that was still attached to the trigeminal ganglion showed increased NGFr(p75)-IR in fibers and supporting cells, as did the motor root within the peripheral mandibular division. These results indicate that the majority of the NGFr(p75)-IR within the main sensory and spinal trigeminal nuclei originates from primary trigeminal afferents and that retrogasserian rhizotomy leads to an up-regulation of NGFr(p75)-IR in the part of the central root that is contiguous with the ganglion.

Ultrastructure of transganglionic degeneration in brain stem trigeminal nuclei during normal primary tooth exfoliation and permanent tooth eruption in the cat.

Electron microscopy is used to study changes in the axons and terminals in the cat brain stem trigeminal nuclei, main sensory, and partes interpolaris and caudalis, during the process of natural tooth shedding. Areas previously showing light optical argyrophilic degeneration products and adjacent areas lacking this degeneration are included. Various types of alteration occur early during tooth loss, including increased presumed glycogen, increased cytoplasmic density, flocculence, lucency, and neurofilamentous hyperplasia. By the stage of maximum exfoliation, terminals and axons of marked density become prominent in areas showing argyrophilia, whereas nondense forms occur elsewhere. By late eruption ages, all forms of degenerated terminals and axons are rare, but phagocytes are heavily laden with similar forms of debris. The sequence of ultrastructural events is discussed in light of recent studies of transganglionic degeneration, their correlation with light microscopic findings, and the potential implications for central plasticity in this system.

Enhanced ultrastructural visualization of the horseradish peroxidase-tetramethylbenzidine reaction product.

Ultrastructural visualization of the horseradish peroxidase-tetramethylbenzidine (HRP-TMB) reaction product within trigeminal ganglion cells and brain stem axons and terminals following HRP injections into the pulpal chambers of cat teeth is enhanced by utilization of a modified osmication procedure that converts the reaction product to a markedly stable and electron-dense form. The results following the use of the modified osmication procedure (pH 5.0 phosphate buffer at 20 degrees C for 12 hours) are compared to results obtained by following Carson's osmication protocol (Carson KA, Mesulam M-M: J Histochem Cytochem 30:425, 1982; Carson KA, Mesulam M-M: In Tracing Neural Connections with Horseradish Peroxidase. Edited by M-M Mesulam. J Wiley, Chichester, England, 1982, p 153-184) (pH 6.0 phosphate buffer at 45 degrees C for 45 min). The results suggest that the conversion of the HRP-TMB reaction product to an electron-dense form during osmication is intimately associated with the pH of the phosphate buffer and the total time of osmication.

Brain stem degeneration patterns following tooth extractions: visualization of dental and periodontal afferents.

The terminal central nervous system distribution of those primary afferent neurons from the teeth and periodontium in cats was studied by degeneration methods. Lesions were created by combinations of tooth extractions and the brain stem was examined at 14, 30 and 60 days survival for degeneration patterns, with 30 days being the optimal survival time. Degenerating axons and terminals are seen bilaterally, but somewhat less on the side contralateral to the lesions and are concentrated in the ventral half of pars interpolaris and pars caudalis near obex. The results are discussed with regard to the current controversies concerning the primary central termination of these trigeminal neurons.

Toxic ricin demonstrates a dual dental projection.

Toxic ricin was used to study the central distribution of dental afferents in the cat. Following intrapulpal ricin injections ganglion cell degeneration is seen in the II and III ganglion divisions. Central argyrophilic degeneration occurs in the dorsal portion of all ipsilateral trigeminal nuclei. Ventral degeneration is seen in the pars interpolaris and pars caudalis. No contralateral degeneration was observed. The results are discussed with regard to previous studies of the central location of dental afferents.

Periodontal regeneration of a class II furcation defect utilizing a bioabsorbable barrier in a human. A case study with histology.

This case report describes human histologic data of periodontal regeneration following guided tissue regeneration therapy (GTR) with a bioabsorbable barrier composed of polylactic acid. The tooth that was examined was part of a previously published study of the clinical effects of GTR therapy without the use of bone or bone substitutes on Class II furcation defects. Twenty-five months following the surgical procedure, the tooth was extracted for non-periodontal reasons. During this extraction, the bone within the furcation that was treated in the study was luxated with the tooth. At the completion of the study (month 12), the furcation's vertical probing depth had decreased by 2 mm with a 2 mm gain in clinical attachment. The horizontal furcation measurement decreased by 3 mm. Following extraction, the tooth was prepared for light microscopy and sectioned in the mesial-distal plane. Reference notches were not placed in the tooth at the time of surgery as there were no plans to perform histologic analysis in the study. However, using the buccal root prominences and what we interpreted to be root planing marks on the cementum, we were able to demonstrate that complete periodontal regeneration occurred on the root surface that was exposed to the pocket environment prior to surgery. New alveolar bone, cementum, and periodontal ligament were consistently observed throughout the furcation in the areas that demonstrated clinical attachment gain and a decrease in horizontal probing depth. This case report adds to the accumulating evidence of histologic periodontal regeneration following guided tissue regeneration with bioabsorbable polylactic acid barriers.

Reliability of crevicular fluid measurements taken in the presence of supragingival plaque.

The measurement of gingival crevicular fluid (GCF) is commonly used in clinical studies to quantitate the severity of gingival inflammation. This study examined the influence of the presence of supragingival plaque on GCF readings. Bilateral pairs of maxillary premolars received replicate GCF measurements. One of the teeth was randomly selected to be the test tooth. Supragingival plaque was removed from the test tooth between the first and second GCF measurements. Plaque was not removed from the control tooth. The crevicular fluid was collected on filter paper strips which were placed just subgingivally. The quantity of crevicular fluid was determined with the aid of the Periotron 6000. The mean difference between the first and second GCF measurement for the control teeth was -1.5 +/- 5.7 (+/- SD). This change was not significant (P = 0.21). The mean difference between the first and second GCF measurements for the experimental teeth (-21.3 +/- 16.5) was significant (P less than or equal to .001). The mean difference between the control and the experimental GCF differences were found to be highly significant (P less than or equal to .001). The data indicate that the presence of supragingival plaque can significantly elevate the GCF measurements when determined with the Periotron 6000.

The pharmacokinetic profile of a biodegradable controlled-release delivery system containing doxycycline compared to systemically delivered doxycycline in gingival crevicular fluid, saliva, and serum.

The primary goal of this study was to characterize the release profile of doxycycline hyclate (8.5% w/w) from a biodegradable controlled-release delivery system (DH) placed in periodontal pockets. Pharmacokinetic data were obtained from gingival crevicular fluid (GCF), saliva, and serum of adult periodontitis patients. These results were compared to those obtained from individuals who received standard oral doses of doxycycline hyclate (200 mg on day 0, then 100 mg/day for 7 days). All participants presented with multiple pockets > or = 5 mm that bled upon probing. At the baseline visit patients receiving local drug delivery had all pockets > or = 5 mm that bled upon probing on one side of the mouth filled with DH. Drug retention was enhanced with 1 of 2 periodontal dressings (non-eugenol [NE] or 2-octyl cyanoacrylate [2-octyl]). Doxycycline concentrations were analyzed with the aid of reverse phase high performance liquid chromatography. GCF saliva, and serum samples were obtained just prior to drug delivery and then at hours 2, 4, 6, 8, 18, 24 and days 2, 3, 5, 7, and 8. GCF and saliva samples were also obtained at days 10, 14, 21, and 28. Thirty two subjects participated in the study; 13 in the NE group, 13 in the 2-octyl group, and 6 in the group taking oral doxycycline. The release of doxycycline in the GCF peaked at 2 hours (1473 microg/ml in the NE group, and 1986 microg/ml in the 2-octyl group). The mean concentration at day 7 was 309 microg/ml for the NE group and 148 microg/ml for the 2-octyl group. Minimal levels of drug were detected in the GCF of the oral doxycycline group with a peak concentration of 2.53 microg/ml at 12 hours. Salivary concentrations for both local delivery groups peaked at hour 2 (4.05 microg/ml for the NE group and 8.78 microg/ml for the 2-octyl group); by the end of day 1 levels were < or = 2 microg/ml. For subjects who took the oral doxycycline, salivary concentrations never exceeded 0.11 microg/ml. Serum concentrations of doxycycline for individuals receiving the local drug delivery never exceeded 0.1 microg/ml. For the oral doxycycline group serum concentrations ranged from 0.91 to 2.26 microg/ml over the 8 days data were collected. The high concentration of drug available at the treated sites coupled with the relatively low levels in the saliva and almost non-existent levels in the serum indicate that this biodegradable controlled-release delivery system displays an appropriate pharmacokinetic profile for the delivery of doxycycline into periodontal pockets.

Use of an amphotericin B lipid complex for treatment of blastomycosis in dogs.

OBJECTIVE: To evaluate efficacy and nephrotoxicity of amphotericin B lipid complex used for treatment of dogs with naturally developing blastomycosis. DESIGN: Prospective clinical trial. ANIMALS: 11 dogs with blastomycosis. PROCEDURE: All dogs were treated with an amphotericin B lipid complex. Two dogs received a cumulative dose of 8 mg/kg of body weight, 1 received a cumulative dose of 10 mg/kg, and 8 received a cumulative dose of 12 mg/kg. RESULTS: The 2 dogs that received a cumulative dose of 8 mg/kg and 1 of the dogs that received a cumulative dose of 12 mg/kg had a relapse of blastomycosis within 30 days after treatment. Seven of the remaining 8 dogs were clinically free of blastomycosis 6 months after treatment. One dog died of an unrelated cause 5.5 months after treatment, but did not have clinical signs of blastomycosis at the time of death. There were not any adverse clinical effects attributable to drug administration in any of the dogs in this study, and none of the dogs developed clinical signs of renal disease or failure. CLINICAL IMPLICATIONS: Amphotericin B lipid complex was a safe and effective treatment for blastomycosis in these dogs.

Rationale for the use of Atridox therapy for managing periodontal patients.

This article reviews the studies that provided the safety and efficacy data essential for the Food and Drug Administration approval of Atridox. These studies detail the clinical effectiveness of Atridox and provide the foundation for an understanding of the use of Atridox in the clinical management of patients with periodontitis. Atridox is a locally delivered, controlled-release system for the administration of high concentrations of doxycycline to the periodontal pocket. Nine-month clinical studies involving more than 800 patients have shown Atridox and scaling and root planing to be superior to placebo and oral hygiene for the efficacy parameters of attachment level, probing depth, and bleeding on probing. The positive clinical effects are consistent throughout a wide range of patients with varied histories of periodontal therapy. The implications of these findings as they relate to clinical practice are briefly addressed.

Putrescine uptake and release by a normal rat small intestine crypt cell line, IEC-6.

IEC-6 cells were cultured on permeable filter inserts with separate access to the apical and basolateral sides. [3H]Putrescine uptake favored the apical side and its release (in Earle's balanced salt solution containing 0.1% bovine serum albumin) was six times greater in the apical-to-basolateral than in the basolateral-to-apical direction. Release in DMEM did not show this preference. The uptake of [3H]putrescine was stimulated approximately 1.3 times the basal level by 10 mM asparagine (ASN) or 5% dialyzed fetal bovine serum whether the [3H]putrescine was added at a concentration of 1 or 100 nM. The increased uptake was maintained for up to 6 h. When [3H]putrescine was removed after 4 h of uptake, the cells continued to release it into the medium on both sides for up to 4 h. Stimulated cells released only 50% as much as unstimulated cells. Unlabeled putrescine reduced the uptake of [3H]putrescine with an IC50 of 1.81 x 10(-6) M (r = 0.9476) and 1.02 x 10(-6) M (r = 0.9967) for unstimulated and ASN-stimulated cells, respectively. When the intracellular putrescine was reduced by difluoromethylornithine, the uptake of [3H]-putrescine was not changed, but its release was inhibited. Sodium was not required for [3H]putrescine uptake or release. Although the stimulated cells attained intracellular levels of [3H]putrescine which, if expressed as concentration based on cell volume, were up to 500 times the original extracellular concentration, a true concentration gradient could not be proven because 85% of the [3H]putrescine was probably bound to polyanions as shown by butanol extraction.

Light- and electron-microscopic localization of primary dental afferents to medullary dorsal horn (pars caudalis).

Light-microscopic (LM) and ultrastructural (electron-microscopic, or EM) identification of primary dental afferents to medullary dorsal horn (MDH) was demonstrated in the cat following injections of horseradish peroxidase (HRP) into pulpal chambers of unilateral maxillary and mandibular posterior teeth, including the cuspids. Use of a new osmication protocol improved and simplified the EM localization of reaction product within the brain stem terminals. LM examination showed that the projection pattern varied between the different levels of MDH. At caudal levels, the labeling was primarily confined to a narrow band consisting of a dense projection to the dorsomedial portion of laminae I and superficial II and a less intense projection to lamina V. The pattern to rostral levels became increasingly more dense and extensive within these same laminae. LM examination of the tooth apex region showed that a limited spread to the periodontal ligament occurred in some cases. EM investigation of the ipsilateral MDH demonstrated reaction product in terminals with synaptic vesicles that are presynaptic to small and medium-sized dendrites. Labeled axonal endings in close association with cell bodies were also observed. No labeled structures were identified in the contralateral MDH. Some of the reaction product found with EM was below the LM limit of resolution, and thus ultrastructural investigation is necessary for a complete analysis of any pathway when using HRP.

Effect of chemically defined diets on antral and serum gastrin levels in rats.

When rats were fed isocaloric amounts of chemically defined diets with variable amounts of protein (8-60%) or fat (0-30%) over a 10-day period, their serum and antral gastrin concentrations were, respectively, 60 and 40% lower than the levels of chow-fed rats. It was also determined that neither the low bulk content of these diets nor their inability to adequately buffer the gastric pH contributed to this response. The time course of this dietary-induced reduction in gastrin levels was investigated and it was found that the serum hormone levels were significantly reduced as early as 1-2 h after chow-fed rats were placed on these chemically defined diets. Antral gastrin levels were maintained at normal levels for 4-5 days after rats started consuming these synthetic diets and fell thereafter. With all of the chemically defined diets tested, the gastrin secretory response to a meal was significantly reduced. It therefore appears that synthetic diets lack some undefined food constituent present in chow that is required for the normal postprandial release of gastrin or, alternatively, that they contain an inhibitory factor which blocks the normal secretory response.

Depression of antral and serum gastrin concentration by food deprivation in the rat.

In rats fasted 4 days, immunoreactive gastrin concentrations decreased to one-third of the fed levels in antral tissue and to one-eight of the fed levels in serum. The number of antral cells that reacted with fluorescent antigastrin antiserum was also correspondingly decreased. After refeeding, serum gastrin returned to normal levels in 6 days, whereas antral gastrin concentration recovered after 9 days. Normal gastrin levels were maintained in rats fed a nutritious liquid diet over a 6-day period, whereas tissue and serum hormone concentrations decreased to low levels in rats placed on a high bulk non-nutritive diet over the same period. These results suggest that food in the gastrointestinal tract is necessary for the maintenance of normal serum and antral gastrin concentration in rats. The effect of food is most likely attributable to chemical constituents and not distention by bulk.

Ultrastructural study of transganglionic degeneration following dental lesions.

Transganglionic degeneration in the trigeminal main sensory nucleus (MSN) and pars interpolaris (PI) was studied in cats following dental lesions. At early survival times, three types of terminal alteration were seen in both MSN and PI: (1) flocculent degeneration, (2) neurofilamentous hyperplasia and, (3) glycogen accumulation. With longer survival times, the magnitude of these terminal alterations increases. Electron dense degeneration was only seen in the ventral half of PI. Phagocytosis of the altered terminals was also observed. The study suggests a plausible explanation for the variations observed in the CNS projection of primary afferents with degeneration and with HRP transport studies.

Ultrastructure of degenerative changes following ricin application to feline dental pulps.

The ultrastructure of degenerative changes within the ipsilateral trigeminal ganglion, and partes caudalis and interpolaris of the spinal trigeminal nucleus in the cat is described following the application of the potent toxin ricin to the tooth pulps of unilateral maxillary and mandibular posterior teeth, including the cuspids. Survival times ranged from 6 to 10 days. Typical changes identified within the ipsilateral trigeminal ganglion included myelin fragmentation and 'compartmentalization' of the axoplasm of medium-sized myelinated axons, while small myelinated and unmyelinated axons underwent a more variable response ranging from electron-lucent to electron-dense changes. The affected cell body was characterized by the presence of swollen, electron-lucent mitochondria, a reduction of cytoplasmic ribosomes and a filamentous hyperplasia. Other changes often included an eccentric nucleus and satellite cell proliferation. Degenerative changes often occurred in isolated elements surrounded by normal profiles, suggesting specificity of ricin within the trigeminal ganglion. Changes within brainstem axons showed both an electron-dense and a lucent, fragmenting type of axonal alteration. Terminal changes ranged from electron-dense to lucent and also included filamentous hyperplasia and 'hyperglycogenesis'. The altered axonal knobs contained round synaptic vesicles that were presynaptic to dendritic profiles and postsynaptic to terminals containing flattened synaptic vesicles. The above brainstem alterations were identified specifically in the following areas: ventrolateral, medial and dorsomedial pars interpolaris; the ventrolateral and mid-dorsal to dorsomedial areas of the marginalis and outer substantia gelatinosa layers of pars caudalis; and in ventral pockets corresponding to lamina V of the medullary dorsal horn. Dense alterations within terminals containing flattened synaptic vesicles that are typically presynaptic to primary afferents in these areas were rare findings, but along with vacuolization of dendritic profiles suggest a trans-synaptic effect possibly due to the exocytosis of ricin. The results are discussed in relation to different reports of dental projections and with regards to patterns of transganglionic degeneration.

Polyamines are important for attachment of IEC-6 cells to extracellular matrix.

The inhibition of ornithine decarboxylase, a rate-limiting enzyme of polyamine biosynthesis, with alpha-difluoromethylornithine in IEC-6 cells (small intestinal crypt cell line) reduces cell migration by 70%, inhibits protein cross-linking, and affects the cytoskeletal assembly. The current study examines the effects of intracellular polyamine depletion on attachment of IEC-6 cells to different matrices. Polyamine deficiency inhibited cell attachment to plastic, laminin, fibronectin, collagen IV, and Matrigel by different extents. Intracellular putrescine restored attachment to all matrices. The presence of a specific inhibitor of protein cross-linking also inhibited attachment to laminin in a dose-dependent manner. The inhibition of cell attachment to plastic and Matrigel was correlated with the inhibition of cell migration. Immunofluorescence studies showed that polyamines are essential for the correct expression of the integrin subunit alpha 2 but not for the expression of the alpha 1-subunit. This study demonstrates that polyamines are important for cell attachment and expression of the integrin alpha 2 beta 1, a putative receptor for collagen and laminin. The impairment of protein cross-linking and the inhibition of the expression of cell surface receptors that bind extracellular matrix (ECM) proteins may be part of the mechanism by which polyamine deficiency retards cell migration in the small intestine.

Dual fluorometric/colorimetric detection system for an automated random-access instrument utilizing standard polystyrene test tubes as precision cuvettes.

To attain the optical precision necessary to precisely quantify fluorescent or colorimetric signals, analytical systems have typically included quality-controlled cuvettes, flow cells, or dual-beam reference systems. We describe a system where a fluorescence or transmittance signal is quantified in single, standard, 12-mm-diameter polystyrene test tubes. Tube-to-tube variation is minimized by referencing the primary signal to a second reference signal. The tube is carefully oriented within a positioner that allows for the precise placement of the tube within a light path 7.6 mm in diameter. The detection system allows for use of either four pairs of fluorescence excitation/emission wavelengths or eight transmittance wavelengths, which are selected by using specific interference filters. The impact of temperature, tube imperfections, surface flaws, and distortions is minimized by using a reference ratio. Fluorescence is measured with an orthogonal photomultiplier tube, and transmittance with a photodiode; both are illuminated with an ordinary long-life tungsten-halogen lamp. This system is used with the Becton Dickinson AFFINITY system, an automated random-access analyzer with analyte-specific unit-package reagents. The polystyrene tube of the reagent package, which has an antibody-absorbed surface, serves as both the cuvette and the separation medium. Use of the reference ratio method reduces intertube imprecision of fluorometric or transmittance signals, for more precise quantification of various analytes.