Decreased beige adipocyte number and mitochondrial respiration coincide with increased histone methyl transferase (G9a) and reduced FGF21 gene expression in Sprague-Dawley rats fed prenatal low protein and postnatal high-fat diets

We have shown that prenatal low-protein (LP) followed by postnatal high-fat (HF) diets result in a rapid increase in subcutaneous adipose tissue (subc-AT) mass in the offspring, contributing to development of obesity and insulin resistance. Studies have shown that a key transcription factor, PR domain containing 16 (PRDM16), and fibroblast growth factor 21 (FGF21) are involved in conversion of precursor cells into mitochondria (mt)-enriched beige adipocytes (BA). Our hypothesis is that a maternal LP and postnatal HF diets increase the risk of obesity and insulin resistance in offspring, in part, by reducing the conversion of precursor cell into BA in the subc-AT of offspring. Using obese-prone Sprague-Dawley rats fed 8% LP or 20% normal-protein (NP) diets for 3 weeks prior to conception and throughout pregnancy and lactation followed by 12 weeks of 10% normal-fat (NF) or 45% HF diet feeding, we investigated whether prenatal LP and postnatal HF diets affect BA number and oxidative respiratory function in subc-AT. Results showed that subc-AT and liver FGF21, PRDM16 and BA marker CD137 mRNA increase with postnatal HF diet in maternal NP group rats. In contrast, rats fed maternal LP and postnatal HF diets showed no increase in subc-AT mt copy number, oxygen consumption rate, FGF21, PRDM16 and CD137 mRNA, whereas protein expression of an inhibitor for FGF21 transcription (histone methyltransferase, G9a) increased. These findings suggest that LPHF diets cause offspring metabolic alterations by reduced BA and FGF21 mRNA and increased G9a protein expression in subc-AT.

Marginal copper deficiency increases liver neutrophil accumulation after ischemia/reperfusion in rats

Copper deficiency can cause a host of major cardiovascular complications including an augmented inflammatory response through effects on both neutrophils and the microvascular endothelium. In the present study, we evaluated the effect of marginal copper deficiency on the neutrophilic response to hepatic ischemia/reperfusion injury, a condition that induces an inflammatory response. Male weanling Sprague-Dawley rats were fed purified diets which were either copper-adequate (6.3 mg/kg) or copper-marginal (1.62 mg/kg) for 4 weeks prior to undergoing 90 min of partial hepatic ischemia followed by 8 h of reperfusion. Liver injury was assessed by serum levels of alanine aminotransferase and by liver histology. Liver neutrophil accumulation was determined by tissue myeloperoxidase content. There was no significant difference in liver injury between copper-adequate and copper-marginal rats. However, liver neutrophil accumulation was significantly increased in copper-marginal rats. These findings were confirmed histologically. Liver expression of the adhesion molecule, intercellular adhesion molecule-1 (ICAM-1), was increased in copper-marginal rats compared to copper-adequate rats. The results suggest that neutrophil accumulation is increased through enhanced ICAM-1 expression in liver of copper-marginal rats after ischemia/reperfusion, but that this does not result in increased liver injury.

Magellan: radar performance and data products

The Magellan Venus orbiter carries only one scientific instrument: a 12.6-centimeter wavelength radar system shared among three data-taking modes. The synthetic-aperture mode images radar echoes from the Venus surface at a resolution of between 120 and 300 meters, depending on spacecraft altitude. In the altimetric mode, relative height measurement accuracies may approach 5 meters, depending on the terrain's roughness, although orbital uncertainties place a floor of about 50 meters on the absolute uncertainty. In areas of extremely rough topography, accuracy is limited by the inherent line-of-sight radar resolution of about 88 meters. The maximum elevation observed to date, corresponding to a planetary radius of 6062 kilometers, lies within Maxwell Mons. When used as a thermal emission radiometer, the system can determine surface emissivities to an absolute accuracy of about 0.02. Mosaicked and archival digital data products will be released in compact disk (CDROM) format.

The Footprint method to assess transmalleolar axis

Torsional deformities of the lower extremities are a common reason for an orthopaedic consultation and are also part of the evaluation of a patient in gait analysis. This study assessed the level of agreement between, and the repeatability of, the Footprint method and two other methods (Prone and Jig) of measuring the transmalleolar axis (TMA) clinically. The Footprint method measures the TMA as the patient sits by projecting the position of the malleoli downwards onto lined paper while the lines of the paper are aligned with the knee axis. The Prone method projects the position of the malleoli upwards onto the sole of the foot and this is related to the visually estimated knee axis. The Jig method uses a tropometer to relate the angle between the tibial tubercle and the two malleoli. Two assessors measured twelve subjects using the three methods and six subjects were re-measured approximately 1 week later for repeatability. There was poor agreement between the three methods but the Footprint method was the most repeatable (coefficient of repeatability: 5.4). One observer then assessed the repeatability of the effect of simulated equinus on the Footprint method in 10 normal subjects on 2 separate occasions 1 week apart. Equinus was obtained by having the subjects sit and firstly extend their knee and place the foot on the floor and secondly by placing the foot under consideration on a wedge. Both conditions introduced an offset into the measurement of the TMA when compared to the measurements with the ankle at neutral in the same subjects. The reliability of the Footprint method was then assessed using 10 inexperienced observers who measured nine normal subjects each on 2 separate occasions and their results compared with those from an experienced observer. The inexperienced observers were less repeatable than an experienced observer (coefficients of repeatability 9.2 and 6.9, respectively). We recommend that different methods of measuring TMA should not be used interchangeably in clinical practice. The Footprint method was the most repeatable of the three methods tested and can be used for patients who have fixed equinus but the measurement was less repeatable when used by inexperienced observers.

Influence of hydroxyl substitution on benzyne properties. quantum chemical characterization of the didehydrophenols

Geometries and singlet-triplet splittings for the 10 geometrical isomers of didehydrophenol are characterized at a variety of levels of electronic structure theory. The influence of the hydroxyl group is primarily to increase/decrease the weight of zwitterionic singlet mesomers that place positive/negative charge adjacent to oxygen in valence bond descriptions of the arynes. For some of the meta isomers, this interaction stabilizes distortion in the direction of a bicyclic geometry. The net effect, relative to the unsubstituted benzynes, is to increase the singlet-triplet splittings in 2,3-, 2,6-, and 3,5-didehydrophenol and to decrease that splitting in 2,4- and 2,5-didehydrophenol (3,4-didehydrophenol is essentially unaffected). As shown for other arynes, the singlet-triplet splittings can also be accurately estimated by correlation with proton hyperfine coupling constants in antecedent monoradicals, these values being accessible from very economical calculations.

Dietary copper and dimethylhydrazine affect protein kinase C isozyme protein and mRNA expression and the formation of aberrant crypts in colon of rats

Low dietary copper has been shown to decrease the expression of various protein kinase C (PKC) isozymes and increase the risk of colon cancer development in experimental animals. The purpose of this study was to investigate the relationship between dietary copper and carcinogen administration on PKC isozyme accumulation and aberrant crypt foci (ACF) formation in rats fed 0.9 and 7.7 microg Cu/g diet. After 24 and 31 d on the diets, the rats were injected with either dimethylhydrazine (DMH) (25 mg/kg i.p.) or saline and killed at two time points (2 wk and 8 wk after DMH). Rats fed low dietary copper had significantly lower (p<0.0001) hematocrits, hemoglobin, ceruloplasmin activity and plasma and liver copper concentrations than rats fed adequate dietary copper. Ingestion of low dietary copper significantly (p<0.005) increased the formation of DMH-induced ACF (116.8 vs 59.6). Low dietary copper significantly (p<0.05) decreased the concentration of PKC alpha, delta, and zeta in the colon at 2 wk but not at 8 wk. Thus, changes in PKC isoform protein concentration may be related to increased susceptibility of copper-deficient animals to colon cancer.

Growth stimulation of Porphyromonas endodontalis by hemoglobin and protoporphyrin IX

Porphyromonas endodontalis, like other Porphyromonas species, has a complex set of nutritional requirements. In addition to being an obligate anaerobe, the bacterium must be grown in a complex medium consisting of amino acids, reducing agents and heme compounds. P. endodontalis accumulates high concentrations of heme pigments to the extent that colonies appear black on blood agar. This accumulation of heme and the need for these compounds has been characterized as iron requirements by these species. However, in our studies, P. endodontalis demonstrated growth dependence on hemoglobin or protoporphyrin IX but not on free iron. Iron added to other heme compounds actually decreased growth stimulation by porphyrin-containing compounds. P. endodontalis actively transported free iron, but this process did not appear to be critical for growth. The maximum stimulation of growth by protoporphyrin IX, under conditions of iron deprivation, suggests that P. endodontalis requires the porphyrin moiety as a growth factor.

Lipid lowering explains the insulin sensitivity enhancing effects of a thiazolidinedione, 5-(4-(2-(2-phenyl-4-oxazolyl)ethoxy)benzyl)-2,4 thiazolidinedione

AIM

Insulin resistance is a characteristic feature of type 2 diabetes and obesity. The present study examined the effects of TZD300512, a thiazolidinedione, on glucose and lipid metabolism in the fatty Zucker rat (fa/fa), a rat model of insulin resistance.

METHODS

TZD300512 was administered (2.0 mg/kg/day) in the diet for 1 week to chronically catheterized Zucker fa/fa rats. We measured triglyceride clearance rate and hepatic triglyceride output. We assessed baseline glucose metabolism, and insulin-mediated glucose uptake. We also determined whether the insulin sensitivity enhancing effects of TZD300512 could be reversed by infusion of Intralipid.

RESULTS

TZD300512 treatment markedly reduced fasting plasma triglyceride by 72% and nonesterified free fatty acids by 46%. Moreover, treatment significantly enhanced plasma triglyceride clearance (AUC; 60.36+/-11.50 v 131.44+/-18.45 mM/min), but hepatic triglyceride output was not altered. Drug treatment significantly reduced fasting plasma glucose by 25%, plasma insulin by 73%, and had no effect on glucagon levels. Glucose infusion rate (GIR) needed to maintain euglycemia during hyperinsulinemic clamp was significantly increased from 34.96+/-3.94 micromol/kg/min to 123.80+/-4.80 micromol/kg/min, while whole body glucose uptake was more than doubled (58.49+/-2.86 control vs. 126.97+/-3.8 treated micromol/kg/min). Insulin-induced suppression of hepatic glucose production was nearly complete with treatment. Intralipid infusion reversed drug-induced improvement in insulin sensitivity.

CONCLUSIONS

These results suggest that TZD300512-favourable alterations in lipid metabolism have a significant impact on its effectiveness in enhancing insulin sensitivity in a severely insulin resistant rodent model of type 2 diabetes.

A comparison of the effects of two burs on endodontic access in all-ceramic high lucite crowns

OBJECTIVE

The purpose of this study was to examine and compare the effects of diamond and tungsten carbide burs with respect to the preparation of access through all-ceramic crowns.

STUDY DESIGN

Thirty extracted maxillary premolars were restored with all-ceramic crowns. Each specimen was assigned to one of two groups: (1) access opening prepared with a round diamond bur; (2) access opening prepared with a carbide fissure bur. Access preparations were scanned by means of scanning electron microscopy; observed were defects categorized as edge chipping, microcracks, and fractures.

RESULTS

Edge chipping around the access was universal. Significant chipping (x > or = 0.1 m) was seen in 43% of access peripheries. Eleven percent of the crowns fractured. chi(2) analysis (P <.05) demonstrated no statistical difference between the bur groups. Results of a t test revealed no statistical difference in edge chipping between the two bur types.

CONCLUSIONS

All-ceramic crowns bonded to extracted maxillary premolars may experience edge chipping, microcracks, and fractures at equal rates whether access is prepared with a round medium coarse diamond bur or a tungsten carbide fissure bur.

Gender influences the effect of perinatal copper deficiency on cerebellar PKC gamma content

Change in cerebellar protein kinase C gamma (PKCgamma) content caused by perinatal copper (Cu) deficiency was determined in 22-day old rats. The offspring of dams with low Cu intake during gestation and lactation exhibited signs characteristic of Cu deficiency including anemia, greater than 90% reduction in liver Cu concentration, and undetectable serum ceruloplasmin. In addition, brain Cu concentrations were reduced 80%. No differences in the signs of Cu deficiency were observed between female and male offspring. However, cerebellar PKCgamma content was reduced 54% (P < 0.05, Tukey's test) in female offspring but only 18% (P > 0.05) in male offspring. Following 6 weeks of Cu supplementation, brain Cu concentrations remained depressed in female and male rats that experienced perinatal Cu deficiency, but cerebellar PKCgamma content was completely restored to control levels. Postnatal expression of PKCgamma in the cerebellum coincides with and regulates cerebellar maturation. The results of the present study indicate perinatal Cu deficiency may impair cerebellar maturation to a greater extent in females than in males. However, it is not clear whether suppression of PKCgamma by perinatal Cu deficiency produces permanent neuropathology in the cerebellum because the effects were reversed by Cu supplementation.

Visible-band testbed projector with a replicated diffractive optical element

Raytheon has designed, fabricated, and tested a diffractive-optical-element-based (DOE-based) testbed projector for direct and indirect visual optical applications. By use of a low-cost replicated DOE surface from Rochester Photonics Corporation for color correction the projector optics bettered the modular transfer function of an equivalent commercial camera lens. The testbed demonstrates that a practical DOE-based optical system is suitable for both visual applications (e.g., head-mounted displays) and visual projection (e.g., tactical sensors). The need for and the proper application of DOE's in visual optical systems, the nature and the performance of the projector optical design, and test results are described.

Radiologic interpretation of bone striae: an experimental study in vitro

OBJECTIVE

The purpose of this study was to determine whether the mandibular alveolar striae patterns seen in radiographs represent trabecular bone.

STUDY DESIGN

Segments of human cadaver mandible were obtained. Two identical radiographs were made of each segment initially, after removal of trabecular bone, after slight smoothing of the endosteal surface, and after aggressive smoothing of the endosteal surface. The radiographs were projected in random pairs for each sample. Six dentists judged whether a difference in the amount of trabecular bone could be detected.

RESULTS

Chi-square test analysis revealed no significant difference in the amount of trabecular bone judged initially and after removal of trabecular bone. A significant difference appeared to exist on radiographs made initially and after slight smoothing. A significant difference was judged to exist on radiographs made after slight removal of the endosteal surface and after aggressive removal of the endosteal surface.

CONCLUSIONS

Mandibular radiographic striae patterns, interpreted as arising from trabecular bone, actually result from bone patterns on the endosteal surface.

Copper deprivation potentiates oxidative stress in HL-60 cell mitochondria

Cytochrome-c oxidase is the copper-dependent terminal respiratory complex (complex IV) of the mitochondrial electron transport chain whose activity in a variety of tissues is lowered by copper deficiency. Because inhibition of respiratory complexes increases the production of reactive oxygen species by mitochondria, it is possible that copper deficiency increases oxidative stress in mitochondria as a consequence of suppressed cytochrome-c oxidase activity. In this study, the activities of respiratory complex I + III, assayed as NADH:cytochrome-c reductase, complex II + III, assayed as succinate:cytochrome-c reductase, complex IV, assayed as cytochrome-c oxidase, and fumarase were measured in mitochondria from HL-60 cells that were grown for seven passages in serum-free medium that was either unsupplemented or supplemented with 50 n M CuSO4. Fumarase activity was not affected by copper supplementation, but the complex I + III:fumarase and complex IV:fumarase ratios were reduced 30% and 50%, respectively, in mitochondria from cells grown in the absence of supplemental copper. This indicates that copper deprivation suppressed the electron transfer activity of copper-independent complex I + III as well as copper-dependent complex IV. Manganese superoxide dismutase (MnSOD) content was also increased 49% overall in the cells grown in the absence of supplemental copper. Furthermore, protein carbonyl groups, indicative of oxidative modification, were present in 100-kDa and 90-kDa proteins of mitochondria from copper-deprived cells. These findings indicate that in cells grown under conditions of copper deprivation that suppress cytochrome-c oxidase activity, oxidative stress in mitochondria is increased sufficiently to induce MnSOD, potentiate protein oxidation, and possibly cause the oxidative inactivation of complex I.

Metabolic and hemodynamic effects of moxonidine in the Zucker diabetic fatty rat model of type 2 diabetes

We studied the effect of moxonidine, an imidazoline ligand, on metabolic and hemodynamic parameters in Zucker diabetic fatty rats, a model of type 2 diabetes. In one group (metabolic group), 8-week-old rats were started on a diet containing either moxonidine (3 or 10 mg x kg(-1) x day(-1)) or vehicle for 4 weeks. Body weight and food intake were monitored daily, plasma insulin and glucose were monitored weekly, and an oral glucose tolerance test (OGTT) was performed at study's end. In another group of rats (hemodynamic group), radio frequency transmitters were implanted 1 week before starting the diet, and mean blood pressure, heart rate, and motor activity were continuously monitored at baseline and for 4 weeks after beginning drug exposure. Moxonidine (10 mg x kg(-1) x day(-1)) significantly decreased elevated glucose levels and prevented the decrease in plasma insulin noted in vehicle-treated or pair-fed groups. Moxonidine also decreased fasting glucose (3 and 10 mg x kg(-1) x day(-1)) and prevented the decrease in fasting insulin (10 mg x kg(-1) x day(-1)) compared with vehicle. Fasting glucose at 10 mg x kg(-1) x day(-1) was equivalent to lean littermates. Both doses significantly increased glucose disposal and the insulin secretory response during the OGTT. Moxonidine lowered daily mean arterial pressure compared with both baseline values and vehicle and decreased daily heart rates. Motor activity was unaffected, except for an increase in the 10 mg x kg(-1) x day(-1) group during low activity periods. Moxonidine did not significantly affect body weight, fluid intake, or urine volume, but the 10 mg x kg(-1) x day(-1) dose reduced urinary protein excretion compared with vehicle-treated animals. These results demonstrate that, in an animal model of type 2 diabetes, the antihypertensive agent moxonidine induces a beneficial effect on abnormal glucose metabolism and renal protein excretion at doses that are effective in lowering arterial blood pressures and heart rate.

Copper and signal transduction: platelets as a model to determine the role of copper in stimulus-response coupling

Platelets from copper-deficient rats have been used as a model to investigate the role of copper in receptor-mediated cellular responses. Copper deficiency doubles the rate of dense granule secretion and increases myosin association with the platelet cytoskeleton following thrombin stimulation. Mechanisms underlying the effects of copper deficiency on thrombin-induced signals that elicit dense granule secretion involve suppression of protein kinase C activity and impairment of Ca2+ release from intracellular stores. Copper deficiency also reduces the cellular GTP content of platelets. This may limit receptor effector coupling through GTP-dependent regulatory proteins leading to protein kinase C activation and the release of Ca2+ from intracellular stores. The reduction in GTP content during copper deficiency results from its utilization to maintain cellular ATP levels in response to severely inhibited cytochrome c oxidase activity in platelet mitochondria. Thus, the role of copper in maintaining normal signal transduction may be indirectly related to its biological function in mitochondria.

Scanning electron microscopy and histologic analysis of an apexification "cap": a case report

A maxillary permanent central incisor with a history of trauma, apexification, and internal thermocatalytic bleaching sustained a horizontal fracture at the cementoenamel junction, which necessitated extraction of the tooth. After removal, the root apex was examined histologically and by scanning electron microscopy. An apexification "cap" with unusual anatomic character and structure was observed.

Storage-phosphor computed radiography versus film radiography in the detection of pathologic periradicular bone loss in cadavers

OBJECTIVES

The purpose of this study was to compare D-speed film, E-speed film, and the Soredex Digora system with respect to the detection of periradicular pathosis.

STUDY DESIGN

Radiographic images of 100 cadaver jaws were made with E-speed film, D-speed film, and the Soredex Digora. Each set of 100 images was interpreted by four observers, with 30 days separating each of three viewing sessions from the next. The presence or absence of pathologic (inflammatory) periradicular bone resorption was determined by histologic examination of the samples. The observer performance was compared with the true histologic findings and evaluated with receiver operating characteristic and corrected receiver operating characteristic analysis.

RESULTS

No statistically significant differences were found in diagnostic performance among the three radiographic techniques. In addition, no imaging technique was a good indicator of pathosis as determined by histologic analysis.

CONCLUSION

Under the conditions of this study, it was determined that D-speed film, E-speed film, and the Soredex Digora were equivalent diagnostic imaging modalities with regard to the detection of pathologic periradicular bone resorption. No technique predictably indicated inflammatory resorption.

Exploratory studies on azole carboxamides as nucleobase analogs: thermal denaturation studies on oligodeoxyribonucleotide duplexes containing pyrrole-3-carboxamide

In order to study base pairing properties of the amide group in DNA duplexes, a nucleoside analog, 1-(2'-deoxy-beta-D-ribofuranosyl)pyrrole-3-carboxamide, was synthesized by a new route from the ester, methyl 1-(2'-deoxy-3',5'-di-O-p -toluoyl-beta-D-erythro-pentofuranosyl)pyrrole-3-carboxylate, obtained from the coupling reaction between 1-chloro-2-deoxy-3,5-di-O -toluoyl-d-erythropentofuranose and methyl pyrrole-3-carboxylate by treatment with dimethylaluminum amide. 1-(2'-Deoxy-beta-D-ribofuranosyl)pyrrole-3-carboxamide was incorporated into a series of oligodeoxyribonucleotides by solid-phase phosphoramidite technology. The corresponding oligodeoxyribonucleotides with 3-nitropyrrole in the same position in the sequence were synthesized for UV comparison of helix-coil transitions. The thermal melting studies indicate that pyrrole-3-carboxamide, which could conceptually adopt either a dA-like or a dI-like hydrogen bond conformation, pairs with significantly higher affinity to T than to dC. Pyrrole-3-carboxamide further resembles dA in the relative order of its base pairing preferences (T >dG >dA >dC). Theoretical calculations on the model compound N-methylpyrrole-3-carboxamide using density functional theory show little difference in the preference for a syntau versus anti conformation about the bond from pyrrole C3 to the amide carbonyl. The amide groups in both the minimized antitau and syntau conformations are twisted out of the plane of the pyrrole ring by 6-14 degrees. This twist may be one source of destabilization when the amide group is placed in the helix. Another contribution to the difference in stability between the base pairs of pyrrole-3-carboxamide with T and pyrrole-3-carboxamide with C may be the presence of a hydrogen bond in the former involving an acidic proton (N3-H of T).

Effect of red blood cells on the growth of Porphyromonas endodontalis and microbial community development

Establishment of a microbial community in the root canal system depends on numerous factors, of which nutrient availability may be one of the most important. We hypothesized that the presence of red blood cells or hemoglobin in this environment could cause shifts in microbial composition of communities, resulting in organisms such as Porphyromonas endodontalis becoming more dominant. An in vitro model system using mixed, batch cultures was performed with the bacteria P. endodontalis, Fusobacterium nucleatum, Peptostreptococcus micros and Campylobacter rectus. Bacteria were cultured in media with or without the addition of washed red blood cells, hemoglobin, or serum. Cyclic growth studies revealed that P. endodontalis was lost from the community of organisms after three cycles. However, inclusion of red blood cells resulted in establishment of this organism. Moreover, red blood cells added to pure cultures of P. endodontalis substantially enhanced growth and protected the organisms from oxygen. We conclude that the presence of red blood cells could result in shifts of microbial communities of organisms within the root canal system.

Template directed incorporation of nucleotide mixtures using azole-nucleobase analogs

DNA that encodes elements for degenerate replication events by use of artificial nucleobases offers a versatile approach to manipulating sequences for applications in biotechnology. We have designed a family of artificial nucleobases that are capable of assuming multiple hydrogen bonding orientations through internal bond rotations to provide a means for degenerate molecular recognition. Incorporation of these analogs into a single position of a PCR primer allowed for analysis of their template effects on DNA amplification catalyzed by Thermus aquaticus (Taq) DNA polymerase. All of the nucleobase surrogates have similar shapes but differ by structural alterations that influence their electronic character. These subtle distinctions were able to influence the Taq DNA polymerase dependent incorporation of the four natural deoxyribonucleotides and thus, significantly expand the molecular design possibilities for biochemically functional nucleic acid analogs.

Coronal leakage of mixed anaerobic bacteria after obturation and post space preparation

OBJECTIVES

The purpose of this study was to assess bacterial leakage of a mixed anaerobic community of organisms in obturated canals after post space preparation.

STUDY DESIGN

A mixed microbial community of strict anaerobic organisms (F. nucleatum, P. micros and C. rectus) was developed. With the use of an in vitro model system, coronal leakage was assessed in 40 anterior teeth after obturation and post space preparation. The specific leakage time in days for each organism to penetrate through the obturating material was determined. In addition, colonization of the apical canal space was assessed by scanning electron microscope after longitudinal splitting of randomly selected specimens.

RESULTS

Eighty percent of the teeth demonstrated coronal leakage of F. nucleatum and C. rectus by the 90 day interval. Bacterial penetration occurred from 48 days to 84 days. Scanning electron microscope examination showed a heterogeneous biofilm of coccal and bacillary species colonizing the apical portion of the canal wall.

CONCLUSIONS

This study demonstrated that coronal leakage phenomena do occur after loss of coronal seals. The model system developed using mixed, anaerobic bacterial cultures is more clinically relevant and may be used to assess bacterial penetration through gutta percha obturation.

Comparison of the base pairing properties of a series of nitroazole nucleobase analogs in the oligodeoxyribonucleotide sequence 5'-d(CGCXAATTYGCG)-3'

The nucleoside analogs 1-(2'-deoxy-beta-D-ribofuranosyl)- 3-nitropyrrole (9), 1-(2'-deoxy-beta-D-ribofuranosyl)-4-nitropyrazole (10), 1-(2'-deoxy-beta-D-ribofuranosyl)-4-nitroimidazole (11) and 1-(2'-deoxy-beta-D-ribofuranosyl)-5-nitroindole (21) were incorporated into the oligonucleotide 5'-d(CGCXAATTYGCG)-3'in the fourth position from the 5'-end. Procedures for synthesis of two of the nitroazole nucleosides, 10 and 11, were developed for this study. Each of the nitroazoles was converted into a 3'-phosphoramidite for oligonucleotide synthesis by conventional automated protocols. Four oligonucleotides were synthesized for each modified nucleoside in order to obtain duplexes in which each of the four natural bases was placed opposite (position 9) the nitroazole. In order to assess the role of the nitro group on base stacking interaction, sequences were also synthesized in which the fourth base was 1-(2'-deoxy-beta-D-ribofuranosyl)pyrazole. Corresponding sequences containing an abasic site, as well as sequences containing inosine, were synthesized for comparison. Thermal melting studies yielded T m values and thermodynamic parameters. Each nucleoside analog displayed a unique pattern of base pairing preferences. The least discriminating analog was 3-nitropyrrole, for which T m values differed by 5 degrees C and Delta G 25 degrees C ranged from -6.1 to -6.5 kcal/mol. 5-Nitroindole gave duplexes with significantly higher thermal stability, with Tm values varying from 35.0 to 46.5 degrees C and -Delta G 25 degrees C ranging from 7.7 to 8.5 kcal/mol. Deoxyinosine (22), a natural analog which has found extensive use as a universal nucleoside, is far less non-discriminating than any of the nitroazole derivatives. Tm values ranged from 35.4 degrees C when paired with G to 62.3 degrees C when paired with C. The significance of the nitro substituent was determined by comparison of the base pairing properties of a simple azole nucleoside, 1-(2'-deoxy-beta-D-ribofuranosyl)pyrazole (12). The pyrazole-containing sequences melt at 10-20 degrees C lower than the corresponding nitropyrazole-containing sequences. On average, the pyrazole-containing sequences were equivalent in stability (average Delta G = -4.8 kcal/mol) to the sequences containing an abasic site (average Delta G = -4.7 kcal/mol).

Acylation of human insulin with palmitic acid extends the time action of human insulin in diabetic dogs

To test whether the binding of insulin to an endogenous serum protein can be used to extend the time action of insulin, human insulin was acylated at the epsilon-amino group of Lys(B29) with palmitic acid to promote binding to serum albumin. Size-exclusion chromatography was used to demonstrate specific binding of the resulting analog, [N(epsilon)-palmitoyl Lys(B29)] human insulin, to serum albumin in vitro, and the time action and activity of the analog were determined in vivo using overnight-fasted, insulin-withdrawn diabetic dogs. In the diabetic animal model, the duration of action of [N(epsilon)-palmitoyl Lys(B29)] human insulin administered intravenously was nearly twice that of unmodified human insulin, and the plasma half-life was nearly sevenfold that of the unmodified protein. Administered subcutaneously, [N(epsilon)-palmitoyl Lys(B29)] human insulin had a longer duration of action; a flatter more basal plasma insulin profile; and a lower intersubject variability of response than the intermediate-acting insulin suspension Humulin L (Lilly, Indianapolis, IN). These studies support the concept that modification of insulin to promote binding to an existing serum protein can be used to extend the time action of human insulin. In addition, the time action, pattern, and decreased variability of response to [N(epsilon)-palmitoyl Lys(B29)] human insulin support the development and further testing of this soluble insulin analog as a basal insulin to increase the safety of intensive insulin therapy.

The synthesis and stability of oligodeoxyribonucleotides containing the deoxyadenosine mimic 1-(2'-deoxy-beta-D-ribofuranosyl)imidazole-4-carboxamide

Oligodeoxyribonucleotides containing the nucleoside analog 1-(2'-deoxy-beta-D-ribofuranosyl) imidazole-4-carboxamide (1) were synthesized by solid phase phosphoramidite technology. Nucleoside 1, which contains a reactive exocyclic amide moiety, was incorporated into synthetic oligodeoxyribonucleotides with the use of a benzoyl protecting group. The corresponding oligodeoxyribonucleotides with dI or dA in the same position in the sequence were synthesized for UV comparison of helix-coil transitions. The thermal melting studies indicate that 1, which could conceptually adopt either a dA- or a dI-like hydrogen bond configuration, pairs with significantly higher affinity to T than to dC. Nucleoside 1 further resembles dA in the relative order of its base pairing preferences (T >dG >dA >dC), but may be less discriminating than dA in its bias for base pairing with T over dG.

In vivo oxidative modification of erythrocyte membrane proteins in copper deficiency

Oxidative stress has been postulated to contribute to the pathology associated with dietary copper deficiency. In vivo, erythrocytes are probable targets of oxidative damage because they are exposed to high concentrations of oxygen and contain heme iron that can autoxidize, which results in the formation of superoxide anions. Activity of the important antioxidant enzyme, copper, zinc superoxide dismutase, decreases markedly in erythrocytes during copper deficiency. The effect of dietary copper deficiency on indicators of oxidative stress was examined in erythrocyte membranes of rats maintained on a purified copper-deficient diet for 35 days after weaning. Erythrocytes were separated into young and old populations on a Percoll gradient prior to membrane isolation and quantification of lipid peroxides and protein carbonyls. Protein carbonyls, determined by Western blot immunoassay, were detected predominantly in both the alpha and beta chains of spectrin. Alpha and beta subunits of spectrin in erythrocyte membranes from copper-deficient rats contained higher amounts of carbonyls than controls, regardless of the population of erythrocytes studied. This study suggests that spectrin may be a specific target for oxidative damage when erythrocyte copper, zinc superoxide dismutase activity is reduced by copper deficiency.

Effect of ultrasonic vibration on post removal in extracted human premolar teeth

The purpose of this study was to determine the effectiveness of ultrasonic vibration in removing Paraposts from extracted teeth. Paraposts were cemented in mandibular premolars to a depth of 9 mm with zinc phosphate cement and the teeth placed in four groups. Group 1 received no vibration. Group 2 received vibration for 4 min, group 3 received vibration for 12 min, and group 4 received vibration for 16 min. Tensile forces were applied to the posts and mean dislodgment forces compared. The mean force (kg) required to dislodge the Parapost in group 1 was 24.92 +/- 1.64 SEM; in group 2, 25.01 +/- 1.80; in group 3, 24.08 +/- 2.29; and in group 4, 12.41 +/- 2.60. There was a significant difference between group 4 and groups 1 to 3 (p = 0.0003). Results of this study indicate that 16 min ultrasonic vibration is an effective method for removing Paraposts from human premolar teeth.

Breakage of ultrasonic root-end preparation tips

Modified ultrasonic tips are used to prepare rootend cavities during endodontic surgery. The purpose of this study was to determine whether such tips are prone to breakage during use. Ten different tip designs were driven by an ultrasonic unit at maximum power. Multirooted teeth were instrumented, the apex removed, and the tooth was placed horizontally on a pan balance. The apex was instrumented by each ultrasonic tip in turn for 15 min, with the load being increased by 100 g every 5 min. Those tips with curvatures of 70 degrees or greater fractured within the first 5-min loading period. Breakage occurred approximately 2 to 3 mm from the end and always at a bend. Scanning electron microscopy revealed that the fractures were brittle in nature, with little change in the remaining section. Two tips bent: one isthmus preparation tip and one silver point removal tip. All the other designs were deemed satisfactory after experimentation. This study shows that fracture of ultrasonic tips can occur and is related to the degree of bending.

Effect of rubber-dam retainers on porcelain fused to metal

Metal ruber-dam retainers may damage tooth structure, restorations, and the porcelain surface of crowns. In this study, effects of metal versus plastic retainers on the surface of porcelain fused to metal (PFM) were compared, specifically: defects at point of beak contact, and porcelain fracturing. Evaluation was performed with scanning electron microscopy (SEM); micrographs were examined for porcelain defects. No damage was evident with metal or plastic retainer placement. In conclusion, neither metal nor plastic retainers consistently damaged PFM surfaces.

Detection of pulpal circulation in vitro by pulse oximetry

Evaluation of pulse oximetry as a potential method of determining pulp vitality was the subject of this research. An in vitro model of pulpal circulation was fabricated to test the design for a dental pulse oximetry sensor. Blood samples equilibrated with hypoxic gas mixtures were circulated through the model by a peristaltic pump. A pulse was simulated by introduction of gas bubbles into the blood circulation. Pulse oximeter readings for saturation were recorded and compared with blood gas analysis results. Statistical analysis revealed no difference between pulse oximetry and blood gas analysis with a highly significant correlation coefficient. Clinical evaluation of this application is currently in progress.

Post and core retention with different cements

In this study, bond strengths of four cement systems--Comspan resin composite luting cement with and without Gluma dentin bond, Fleck's zinc phosphate cement, and Ketac-Cem glass ionomer--used in cementing cast post-cores were investigated. Gluma appears to enhance the bond at the post/tooth interface, resulting in decreased variability and increased strength.

Iron and copper requirements for proliferation and differentiation of a human promyelocytic leukemia cell line (HL-60)

Trace mineral deficiencies tend to have profound effects on the integrity of formed blood elements. Anemia and neutropenia are commonly seen in copper (Cu) deficiency. We therefore developed a serum-free medium to examine the trace mineral requirements, in particular iron and Cu, for proliferation and retinoic acid (RA)-induced differentiation of HL-60 cells. This defined medium (DFM) was composed of Iscove's Modified Dulbecco's Medium (IMDM) supplemented with insulin and human apo-transferrin (each at 5 micrograms/ml) and 1.4 microM FeSO4. The iron concentration range for optimal cellular proliferation was narrow (2-3 microM). HL-60 cells could be maintained in DFM for 15 passages with a doubling time of 38-40 hr. The Cu content of IMDM was very low. Thus, by the fourth passage in DFM, the activity of cuproenzymes (cytochrome c oxidase, CCO; and copper-zinc superoxide dismutase, CuZnSOD) began to decline. Supplementation of DFM with CuSO4 (50 nM) restored enzyme activities. Treatment of cells with a Cu chelator (tetrathiomolybdate, 1 microM) rapidly reduced the activities of both CCO and CuZnSOD. Over the Cu concentration range examined (5-350 nM), Cu supplementation had little effect on HL-60 proliferation. Cell retained the ability to differentiate along the granulocytic pathway when treated with RA, but seemed to be less sensitive to the inducing agent except at the highest concentration tested (1 microM). This decreased sensitivity to RA did not seem to be related to the Cu status of the cells but rather to the absence of a component of serum. Indeed, cells grown in DFM regained their sensitivity to RA when allowed to differentiate in IMDM with 5% serum. These data indicate that the processes of growth and terminal differentiation in HL-60 cells are not greatly influenced by Cu. Thus, it seems likely that the insult resulting in neutropenia which is associated with Cu deficiency may occur earlier than the promyelocytic stage. However, the possibility that the mechanisms contributing to neutropenia may be unrelated to primary defects in the biochemistry of neutrophil maturation cannot be ruled out.

Copper deficiency increases cytochrome P450-dependent 7-ethoxyresorufin-O-deethylase activity in rat small intestine

Although impaired heme synthesis during copper deficiency may limit the production and function of hemoproteins, little is known about the effects of copper deficiency on the cytochromes P450, an important family of hemoproteins, in the small intestine. A series of experiments was conducted to examine the effects of copper deficiency on cytochrome P450 content, ethoxyresorufin-O-deethylase (EROD) activity, and NADPH-cytochrome P450 reductase activity in rat small intestine. Sixteen hours after a single oral administration of 5,6-benzoflavone (BF), an inducer of cytochromes P4501A1 and P4501A2, intestinal cytochrome P450 content was elevated as indicated by the CO-difference spectrum of the reduced cytochrome and by immunoblotting using anticytochrome P4501A1/1A2. However, cytochrome P450 content, measured by either method following BF induction, was not affected by copper deficiency. Thus, copper deficiency did not impair the availability of heme for cytochrome P450 synthesis in the small intestine. Even though copper deficiency did not affect intestinal cytochrome P450 content, EROD activity, which is a cytochrome P450-associated monooxygenase activity, was 9-fold higher in copper-deficient rats compared with controls following BF treatment. The finding that copper deficiency has no effect on intestinal cytochrome P450 content suggests that the increased EROD activity results from an effect of copper deficiency on the cytochrome P450 reductase component of the monooxygenase system. Measurement of cytochrome P450 reductase activity showed a 2-fold increase in the small intestines of copper-deficient rats compared with controls. It is possible, therefore, that increased intestinal cytochrome P450 reductase activity during copper deficiency increases EROD activity by facilitating the flow of electrons to cytochrome P450 during the redox cycle that cytochrome P450 undergoes during the O-deethylation of ethoxyresorufin.

Amelioration of effects of severe dietary copper deficiency by food restriction in rats

To test the effect of food restriction on responses to dietary copper deficiency, male weanling rats were fed two amounts of dietary copper via five dietary-intake regimens ranging from ad libitum to 70% of ad libitum intake. Copper-deficient rats exhibited characteristic signs, including depressed organ copper content, reduced activity of copper-dependent enzymes, enlarged hearts, and anemia. Food restriction attenuated the cardiac enlargement, red blood cell defects, and reduction of superoxide dismutase activity in copper-deficient rats. Mineral and enzyme assays suggested that possible mechanisms for this amelioration are the correction of copper status and/or the improvement of antioxidant status. Also, food restriction depressed serum cholesterol and enhanced cytochrome c oxidase activity in both copper-adequate and copper-deficient rats, which compensated for effects of copper deficiency. A second experiment illustrated that the mortality associated with severe copper deficiency was also inhibited by food restriction.

Measurement of blood flow to osseous tissue in dogs using the radiolabelled microsphere method

1. The purpose of this study was to examine bone blood flow in various intra- and extra-oral sites. 2. The radiolabelled microsphere method was utilized to assess osseous blood flow in the following regions of 10 dogs: rib, long bone, and anterior and posterior regions of the maxilla and mandible. 3. Samples of cancellous and cortical bone were also obtained from each of these regions with the exception of the maxilla and the anterior mandible. 4. Mean blood flow ranged from 3.71 +/- 0.81 (SE) ml min.-1 100 g-1 in the mandibular posterior cortical bone to 22.7 +/- 4.66 ml min-1 100 g-1 in the cancellous rib samples. 5. Blood flow to the cancellous tissue of the rib was significantly greater (P < 0.05) than the other tissues with the exception of maxillary posterior bone and cortical rib. 6. Results from this study indicate that blood flow to the maxillary posterior bone is relatively high, but blood flow in other intraoral osseous sites is significantly less than that of cancellous rib bone.

Effects of systemic and topical nicotine on pulpal blood flow in dogs

It has been suggested that nicotine exerts cardiovascular effects which are similar to stimulation of the sympathoadrenal system. If this observation is true, nicotine administration would decrease pulpal blood flow and possible alter the pulpal response to injury. The purpose of this study was to measure pulpal blood flow in dogs using the radiolabelled microsphere method following topical or systemic administration of nicotine for 28 days. Thirteen dogs were divided into three groups. Group one received topical nicotine (8 mg nicotine/kg/day) combined with orabase which was applied in two equal doses to the mandibular anterior gingiva. Group two received systemic nicotine (2.5 mg/kg/day) delivered by osmotic pumps implanted subcutaneously in the back of each animals' neck. Group three were controls, and these animals received either topical orabase twice daily applied to the mandibular anterior gingiva or saline via osmotic pumps. Results indicated pulpal blood flow increased from Day 0 to Day 28 in both nicotine treated groups. Group one (topical nicotine) exhibited a mean increase in blood flow of 21.8 ml/min/100 g, while group two exhibited a mean increase of 50.1 ml/min/100 g. Group three, the control animals, exhibited a mean decrease in pulpal blood flow of 22.1 ml/min/100 g over the 28-day interval. These changes were not statistically significant (p > 0.05).

Intracellular calcium mobilization in rat platelets is adversely affected by copper deficiency

The influence of copper deficiency on the mobilization of Ca2+ from intracellular stores following ionomycin treatment or thrombin activation of rat platelets was examined using the fluorescent indicator, fura-2, to measure changes in cytosolic Ca2+ concentration ([Ca2+]i). Platelets, obtained from copper-deficient and control rats and loaded with fura-2, were suspended in medium containing 1 mM EGTA and no added Ca2+. The size of the internal Ca2+ pools in the suspended platelets was estimated from the rise in [Ca2+]i following maximal discharge of stored Ca2+ by treatment with 1 microM ionomycin. Peak [Ca2+]i following ionomycin treatment was lower in platelets from copper-deficient rats compared to control rats (148 +/- 27 nM vs. 188 +/- 17 nM), suggesting that the size of the Ca2+ storage pools was decreased by copper deficiency. Furthermore, once internal Ca2+ stores were discharged by ionomycin, [Ca2+]i remained elevated in platelets from copper-deficient rats, but decreased in control rats. These data indicate that copper deficiency may inhibit the efflux of Ca2+ from platelets after its release from internal stores by ionomycin treatment. In platelets from copper-deficient and control rats, stimulation with 0.1 U/ml thrombin led to rapid rise followed by a slow decay in [Ca2+]i. However, peak [Ca2+]i was lower in platelets from copper-deficient rats than in control rats (94 +/- 19 nM vs. 131 +/- 16 nM). These findings imply that by reducing the amount of Ca2+ available for release from intracellular stores, copper deficiency also reduces [Ca2+]i following thrombin activation in the absence of external Ca2+.

Human microsomal glucose-6-phosphatase system

The discovery of glucose-6-phosphatase (EC 3.1.3.9) and of its physiological function in releasing glucose from the liver are discussed briefly. The identification by the Coris of glucose-6-phosphatase deficiency as the underlying defect in certain cases of glycogenosis (type I glycogenosis; von Gierke disease) is described. Characteristics of the catalyst, with a focus on its multiplicity of functions and multicomponent character, are considered with an emphasis on the human liver enzyme. Pioneering studies from the author's laboratory leading to the characterization of two variants of type I glycogenosis, types Ib and Ic, are described.

Restoration of endodontically treated teeth

Criteria have been presented for the evaluation of and treatment planning for endodontically treated teeth for final restoration. The dentist must consider the advantages and disadvantages of saving teeth according to their eventual role in restoring occlusal function, arch integrity, and esthetics. The prognosis is dependent on successful endodontic therapy, the presence of sound periodontal support, and an acceptable restorative effort. Currently accepted post and core systems and materials have been reviewed.

Effects of topical and systemic nicotine on gingival blood flow in dogs

It has been suggested that due to its vasoconstrictive action, nicotine may have a deleterious effect on the periodontium. This study examined the effects of topical and systemic nicotine administration on gingival blood flow. Eighteen young adult dogs were divided into three groups receiving the following treatments for 28 days; topical nicotine in orabase, systemic nicotine via osmotic mini-pumps, and topical orabase or systemic saline via osmotic mini-pumps. Blood flow to the gingiva was measured (at days 0 and 28) by the radiolabeled microsphere method. Blood flow was consistently increased from day 0 to day 28 in the nicotine-treated animals. Comparison of days 0 and 28 blood-flow values demonstrated a statistically significant change (p less than 0.05) in the anterior regions of the topical-nicotine group as compared with the control group. The increased flow may be a reflection of the mode of nicotine delivery and timing of the blood-flow determination procedures.

Gestational alcoholism and fetal zinc accretion in Long-Evans rats

An animal study was conducted to examine the effects of alcohol consumption on placental transfer of zinc during late gestation. Throughout pregnancy, rat dams were fed a nutritionally adequate diet with 30% of total kcal as alcohol. On days 18 and 21 of pregnancy, zinc-65 was injected subcutaneously into the dams and the dams were killed 24 hours later; tissues were removed for analyses. Maternal serum, liver, kidney, and heart zinc decreased with gestational age while total fetal zinc increased. Neither the decrease in maternal organ zinc nor fetal accretion were affected by alcohol consumption. Placental zinc concentration also declined with developmental age and was not influenced by alcohol consumption. The decrease in placental zinc was accompanied by a decrease in zinc associated with 4-10-kD proteins of placental cytosol. Our results suggest that zinc flux during late rat gestation is a well-regulated process that is not influenced by alcohol consumption. Coordination of the transfer apparently is influenced by maternal blood concentration of zinc, placental zinc-binding proteins, and fetal demand for zinc.

Effect of streptozocin-induced diabetes on insulin-receptor tyrosine kinase activity in obese Zucker rats

We examined insulin binding, insulin-stimulated autophosphorylation, and phosphorylation of poly(Glu.Na,Tyr)4:1 by liver and skeletal muscle insulin receptor from lean, obese, and obese streptozocin-induced diabetic Zucker rats. Induction of diabetes with streptozocin (30 mg/kg) lowered the lasting insulin level from 11.4 to 3.8 ng/ml, which was not significantly greater than the lean control level. Autophosphorylation and tyrosine kinase activity of liver insulin receptors were increased 70-100% in the obese control group (relative to lean rats), but diabetes reversed this hyperresponsiveness to insulin. In muscle, obesity was associated with a 40-50% decrease in autophosphorylation and tyrosine kinase activity, which was also reversed in the diabetic state. Autophosphorylation and tyrosine kinase activity were significantly correlated in liver and muscle and were also correlated with fasting insulin levels. These data suggest that insulin-receptor tyrosine kinase activity is regulated differently in liver and muscle and that the abnormalities in kinase activity associated with the obese Zucker rat are at least partly secondary to hyperinsulinemia.

Altered cytoskeletal organization and secretory response of thrombin-activated platelets from copper-deficient rats

The cytoskeletal organization that occurs following thrombin-induced activation of platelets was investigated in rats consuming either a copper-deficient diet containing less than 1 microgram Cu/g or a copper-adequate diet containing 5.5 micrograms Cu/g. Within 30 s following thrombin activation, the amount of polymerized actin in Triton X-100 extracts of whole platelets from copper-deficient rats was greater than the amount in platelets from copper-adequate rats. Electrophoretic analysis of the cytoskeletal proteins obtained from low speed centrifugation of the Triton X-100 extracts indicated that the myosin content of the cytoskeleton increased with time and reached higher levels following activation in platelets from copper-deficient rats. Actin content of the cytoskeleton also increased with time following activation. However, the difference in cytoskeletal actin content of platelets from copper-deficient and copper-adequate rats was not as great as that observed for myosin. The rate of ATP secretion from thrombin-activated platelets was also increased by copper deficiency. Myosin association with the platelet cytoskeleton may be involved in platelet secretion following thrombin activation. Thus, the increased association of myosin with the cytoskeleton and concomitant increase in ATP secretion suggest that the normal mechanism for stimulus-response coupling is altered in thrombin-activated platelets from copper-deficient rats.

Influence of iron and the sex of rats on hematological, biochemical and immunological changes during copper deficiency

The influence of dietary iron and the sex of rats on suppressed lymphocyte functions caused by copper deficiency was examined. Male and female weanling Lewis rats were fed two concentrations of copper (0.6 or 5.6 micrograms Cu/g diet) and iron (50 or 300 micrograms Fe/g diet) for 42 d. Regardless of dietary iron concentrations, male and female rats consuming low copper diets had lower serum ceruloplasmin activity and serum and liver copper concentrations than those fed the high copper diet. However, hemoglobin and hematocrit levels were higher in copper-deficient females than in copper-deficient males and were unaffected by copper deficiency in females fed the high iron diet. Copper-deficient females also had higher serum and liver iron concentrations than copper-deficient males. Proliferation of concanavalin A (Con A)-stimulated spleen lymphoid cells (SLC) was suppressed in copper-deficient males and females, but the suppression was less in the females. Thus, the primary cause of suppressed SLC proliferation in copper-deficient rats is poor copper status; poor iron status induced by copper deficiency had little influence on proliferation.

Limited dermal ossification: a case report

A case is reported of a 10-year-old girl with ossification of the dermis in a limited distribution. The patient has no underlying disorder of calcium or phosphate metabolism and the ectopic bone has been analyzed and found to be identical to normal membranous bone. The ectopic ossification has bridged several of the joints of the patient's upper and lower extremities. At present, the patient is nonambulatory, but has no respiratory or cardiac abnormalities. Her mental status and IQ are normal.

The effect of inferior alveolar nerve resection on dentin formation

The purpose of this investigation was to quantitatively evaluate the effects of inferior alveolar nerve resection on dentinal structures of dogs with the use of fluorescent tissue-time markers. After resection of the mandibular right inferior alveolar nerve and an experimental interval of 70 days, dentin formation was determined from serial cross sections through the mandibular canines. Results indicated that denervation did not appear to affect secondary dentin formation in the canine teeth of dogs.