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In 2007, the International Commission on Radiological Protection (ICRP) revised estimates of the radiosensitivity of tissues including those in the maxillofacial region. The authors conducted a study to reassess patients' risk related to common dental radiographic exposures using the 2007 ICRP recommendations.

Bisphosphonates are used widely to manage skeletal disorders resulting from malignancies that destroy bone and from some metabolic bone diseases. A strong association between bisphosphonate treatment and the appearance of painful exposed nonvital bone in the mandible and maxilla after oral surgery has been reported in the last decade. Extensive reviews have appeared in the dental literature regarding bisphosphonate-related osteonecrosis of the jaws (BRONJ), including protocols for diagnosis, management and diagnostic imaging for early detection; feature definition; and determination of extent of the disease.

Hedgehog (Hh) pathway activation promotes tumors in several endodermally derived tissues, but its role in the pathogenesis of hepatocellular carcinoma (HCC) is unknown. Although normal hepatocytes lack Hh signaling, activation of the Hh pathway in endodermal progenitors is required for liver development. Thus, we hypothesized that hepatocarcinogenesis may involve regulation of Hh signaling. This pathway is activated when Hh ligand binds to its receptor, Patched (PTC). In an unoccupied state, PTC normally functions as a tumor suppressor that inhibits Smoothened (SMO), a proto-oncoprotein, from activating downstream components and transcription of target genes. Here we show that in HCCs, overexpression of the Smo proto-oncogene, as well as an increase in the stoichiometric ratio of Smo to Ptc mRNA levels, correlated with tumor size, a prognostic indicator in HCC biology. In one tumor we identified a novel Smo mutation in an evolutionarily conserved residue. We also demonstrated that HCC cell lines (HepG2 and Hep3B) expressed Hh pathway components and activated Hh transcriptional targets. In Hep3B cells, cyclopamine, an inhibitor of wild-type SMO, had no effect, but KAAD-cyclopamine, a blocker of oncogenic SMO, inhibited Hh signaling activity by 50%, decreased expression of the hepatocarcinogenic oncogene, c-myc, by 8-fold, and inhibited the growth rate of Hep3B cells by 94%. These data support our hypothesis that Hh signaling is dysregulated in human hepatocarcinogenesis. We demonstrate that overexpression and/or tumorigenic activation of the Smo proto-oncogene mediates c-myc overexpression which plays a critical role in hepatocarcinogenesis and suggests that Smo is a prognostic factor in HCC tumorigenesis.

Objective:The purpose of this study was to determine whether the method of reconstruction of tuned-aperture computed tomography (TACT) slices has an influence on observer performance in caries detection. Study Design:Eight images of each of 40 extracted posterior teeth were acquired by using a solid state intraoral detector. Stacks of tuned-aperture computed tomography slices were generated by using the minimum and average reconstruction methods. Slices of the 2 experimental conditions were presented to 8 observers in a balanced order. Images were viewed on a highresolution 21-in color monitor. Observers scored the presence/absence of caries by using a 5-point confidence scale. Observers' assessments were compared with histologic examinations of tooth sections. Receiver operating characteristic curves measured observers' diagnostic performance. Analysis of variance was used to test for possible significant differences between observers and between experimental conditions. Sensitivity, specificity, accuracy, and interobserver reliability were also calculated. Results:No statistically significant differences between the 2 methods of reconstruction were found for the detection of either occlusal (P=.07) or proximal (P=.52) caries. Interobserver reliability was similar for both experimental conditions. Conclusions.:The minimum and average methods of TACT reconstruction provide comparable performances for caries detection tasks. (ORAL Surg Oral Med Oral Pathol Oral Radiol Endod 2001;92:576-81)

Objective:The purpose of this study was to determine whether projection geometry and angular disparity of basis images used for tuned-aperture computed tomography (TACT) slice generation influence observer performance in caries detection. Study Design:Four sets of 8 projections of each of 40 teeth were acquired by using a digital sensor. Each set was radially distributed and subtended angular disparities of 10°, 20°, 30°, and 40°, representing strict projection geometries. A fifth set of images was acquired by using unconstrained geometry. TACT slices were generated from all experimental conditions and presented to 8 observers who viewed the images on a high-resolution monitor. Observers scored the presence/absence of caries with a 5-point confidence scale. Ground truth was achieved by histologic examination of tooth sections. Receiver operating characteristic curves measured observers’ diagnostic performance. Analysis of variance was used to test for significant differences among observers and between experimental conditions. Results:No statistically significant difference between angular disparities was found for the detection of either occlusal (P=.105) or proximal (P=.052) caries. No statistically significant difference between unconstrained and stringent projection geometries was found for the detection of either occlusal (P=.879) or proximal (P=.130) caries. Conclusions:Angular disparities ranging from 10° to 40° provide comparable performance in caries detection with TACT. Both unconstrained and stringent projection geometries may be used when reconstructing TACT slices for caries detection tasks. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;92:353-60)

Objective:The purpose of this study was to compare both subjective (Periapical Index, PAI) and objective (densitometric) radiographic evaluation of healing after endodontic treatment for apical periodontitis. Study Design:Standardized radiographs of 103 teeth taken at baseline (immediately after endodontic treatment) and at 1, 4, 12, 26, and 52 weeks were evaluated. Consensus PAI scores obtained from 7 calibrated observers served as “true scores.” Densitometric estimates of periapical status were obtained from digitized radiographs as the ratio of mean gray value of an area of radiolucency (AR) to an adjacent and similar-sized normal (N) area (AR/N). The selected regions of interest on baseline images were automatically superimposed on postoperative images. All estimates of change were measured with respect to baseline. The subtraction estimate was expressed as ARS-NS. Linear regression was used to analyze longitudinal changes against baseline and to assess the relationship of PAI and AR/N and of change in PAI with respect to baseline and ARS-NS. Results:Five hundred fifty-six PAI scores were generated, with 547 AR/N values and 444 subtraction estimates. PAI, AR/N, and ARS-NSdemonstrated statistical significance for change (P≤.05) starting at 12 weeks. PAI was significantly correlated with AR/N (P<.0001), as was CHPAI with ARS-NS(P<.024). Conclusion:The PAI and 2 densitometric estimates (AR/N and ARS-NS) detected healing of apical periodontitis at 12 weeks after treatment. No difference could be observed among the methods.(Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;92:108-15)

Aphthous ulcers are common and painful. Current treatments are palliative and focused on pain reduction. This article reports on the clinical trials of a novel, bioadhesive treatment modality.

Objective:A high-resolution charge-coupled device was used to compare the diagnostic performances obtained with Trophy’s new RVGui sensor and Kodak Ektaspeed Plus film with respect to caries detection. Study Design:Three acquisition modes of the Trophy RVGui sensor were compared with Kodak Ektaspeed Plus film. Images of the proximal surfaces of 40 extracted posterior teeth were evaluated by 6 observers. The presence or absence of caries was scored by means of a 5-point confidence scale. The actual caries status of each surface was determined through ground-section histology. Responses were evaluated by means of receiver operating characteristic analysis. Areas under receiver operating characteristic curves (AZ) were assessed through analysis of variance. Results:The mean AZscores were 0.85 for film, 0.84 for the high-resolution caries mode, and 0.82 for both the lowresolution caries mode and the high-resolution periodontal mode. These differences were not statistically significant (P= .70). The differences among observers also were not statistically significant (P= .23). Conclusion:The performance of the RVGui sensor in high- and low-resolution modes for proximal caries detection is comparable to that of Ektaspeed Plus film. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;91:381-5)

Objectives.This study reports film speed, contrast, exposure latitude, resolution, and response to processing solution depletion of Kodak Insight intraoral film. Methods.Densitometric curves were generated by using International Standards Organization protocol. Additional curves were generated for Ultra-speed, Ektaspeed Plus, and Insight films developed in progressively depleted processing solutions. Eight observers viewed images of a resolution test tool for maximum resolution assessment. Images of an aluminum step-wedge were reviewed to determine useful exposure latitude. Results.Insight’s sensitivity in fresh automatic processor solutions places it in the F-speed group. An average gradient of 1.8 was found with all film types. Insight provided 93% of the useful exposure latitude of Ektaspeed Plus film. Insight maintained contrast in progressively depleted processing solutions. Like Ektaspeed Plus, Insight was able to resolve at least 20 line-pairs per millimeter. Conclusions.Under International Standards Organization conditions, Insight required only 77% of the exposure of Ektaspeed Plus film. Insight film provided stable contrast in depleted processing solutions. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;91:120-29)

Objective.This study compares the physical characteristics of the RVG UI sensor (RVG) with Ektaspeed Plus film. Study Design.Dose-response curves were generated for film and for each of 6 available RVG modes. An aluminum step-wedge was used to evaluate exposure latitude. Spatial resolution was assessed by using a line-pair test tool. Latitude and resolution were assessed by observers for both modalities. The RVG was further characterized by its modulation transfer function. Results.Exposure latitude was equal for film and RVG in the periodontal mode. Other gray scale modes demonstrated much lower latitude. The average maximum resolution was 15.3 line-pairs per millimeter (lp/mm) for RVG in high-resolution mode, 10.5 lp/mm for RVG in low-resolution mode, and 20 lp/mm for film (P<.0001). Modulation transfer function measurements supported the subjective assessments. Conclusions.In periodontal mode, the RVG UI sensor demonstrates exposure latitude similar to that of Ektaspeed Plus film. Film images exhibit significantly higher spatial resolution than the RVG images acquired in high-resolution mode. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;91:109-19)

Objective.A device to standardize imaging was coupled with a digital intraoral camera to investigate the efficacy of 2-octyl cyanoacrylate (OC) tissue adhesives on the healing of minor aphthous ulcers. Study design.Forty-two subjects were enrolled in a patient-blinded, sham-controlled study assessing the effects of 2-OC formulations on ulcer size and healing time. Daily images were made until ulcers were healed. Ulcer image outlines were traced by using a mouse, and ulcer areas were automatically calculated. Results.A mean difference of –0.15 mm2was seen between baseline and next-day measurements (P= .48). The cumulative ulcer area was meaningfully reduced in one OC group compared with the sham group (P= .04). Time to healing was reduced by 1.9 days in the same group compared with the sham group (P= .02). Conclusions.The use of digital intraoral images with an integrated measurement reference enhances the accuracy and reproducibility of measurements. 2-OC adhesives hold promise as devices to promote healing of recurrent aphthous ulcers. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2000;89:425-31)

This updated self-assessment exercise for the dental team by the Radiology Practice Committee of the American Academy of Oral and Maxillofacial Radiology is intended to produce the highest quality diagnostic radiographs while keeping patient exposure as low as is reasonably achievable. To continue to provide the best radiographic services to patients, those involved in dental radiography need to be aware of the latest changes and advances in dental radiography and need to use them in their practice. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2000;89:369-74)

Objective: To determine the ability of the human immunodeficiency virus type 1 (HIV-1) gene vprto induce cell-cycle arrest in cervical cancer cells with or without human papillomavirus (HPV) type 16 E6 or E7 expression.

Objective.Automatic exposure control has been used successfully in medicine to improve image quality and reduce the number of retakes necessitated by inadequate operator selection of exposure factors. The purpose of this study was to assess the influence of automatic exposure control on panoramic image quality. Study design.A total of 352 patients were imaged with either the OP 100 or the Orthophos Plus panoramic machine. An expert consensus panel judged film quality using a 5-point scale. Differences in quality that would have resulted from the use of operator-determined exposures were calculated through use of an algorithm validated with test images of a human phantom. Results.McNemar’s test demonstrated significant improvements in quality with automatic exposure control (P= .001) in comparison with manual exposure control. No quality difference was found between the 2 machines (P= .9661). Manual exposure selection by oral and maxillofacial radiology residents was better than selection by technologists and assistants (P= .006). Conclusions.This study confirms the utility of automatic exposure control for panoramic radiography. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:518-23)

The vprgene from the human immunodeficiency virus type-1 (HIV-1) encodes a 14-kDa protein that prevents cell proliferation by causing a block in the G2phase of the cell cycle. This cellular function of vpris conserved in evolution because other primate lentiviruses, including HIV-2, SIVmac, and SIVagmencode related genes that also induce G2arrest. After G2arrest, cells expressing vprundergo apoptosis. The signaling pathways that result in vpr-induced cell cycle arrest and apoptosis have yet to be determined. The p53 tumor suppressor protein is involved in signaling pathways leading to cell cycle arrest and apoptosis in a variety of cell types. In this work, we examine the potential role of p53 in mediating cell cycle block and/or apoptosis by HIV-1 vprand demonstrate that both phenomena occur independently of the presence and function of p53. Caspases are common mediators of apoptosis. We examined the potential role of caspases in mediating vpr-induced apoptosis by treating vpr-expressing cells with Boc-D-FMK, a broad spectrum, irreversible inhibitor of the caspase family. Boc-D-FMK significantly reduced the numbers of apoptotic cells induced by vpr.Therefore, we conclude that vpr-induced apoptosis is effected via the activation of caspases.

Plasma catecholamines increase markedly during labor and delivery. Moreover we have noted greater increases at birth in preterm than term lambs. It was unclear whether these differences were due to differences in secretion or clearance. We therefore designed experiments to compare the metabolic clearance rates (MCR) and plasma appearance rates of norepinephrine (NE) and epinephrine (E) in chronically catheterized term (143 ± 1 days) and preterm (131 ± 1 days) fetal sheep. Two different techniques, radioisotope tracer techniques and infusion of cold hormones for estimation of clearance rates, were compared systematically in the same group of animals. The results demonstrate that MCR of NE in term fetuses (178 ± 28 ml·kg−1min−1) is similar to preterm fetuses (205 ± 22 ml·kg−1min−1) as is MCR for E (193 ± 28 versus170 ± 33 ml·kg−1min−1, respectively). Estimates of MCR from cold hormone infusion were highly dependent on infusion rate with estimtes as much as 150 above that determined by isotope tracer infusions. Plasma appearance rates for both NE and E in term and preterm animals were similar. There were no detectable physiologic alterations during the tracer isotope infusions whereas infusions of cold hormone were associated with marked alterations in heart rate and blood pressure. These results suggest: 1) there are no differences in MCR or plasma appearance rates of NE or E between 130 days gestational age and term fetal sheep; 2) cold hormone infusions overestimate MCR and plasma appearance rates of both NE and E when compared to radioisotope tracer infusions; 3) differences in catecholamine concentrations at birth between term and preterm animals appear to be due to differences in secretion rather than clearance.

Dental professionals were reluctant to accept Ektaspeed (Eastman Kodak Co.) intraoral film despite its X-radiation dose-sparing advantages for patients. One reason may have been Ektaspeed film's known sensitivity to long-term storage as compared with that of Ultra-speed film (Eastman Kodak Co.). In 1995, Kodak replaced Ektaspeed with Ektaspeed Plus, claiming it had better resolution and higher stability than Ektaspeed, as well as equal exposure radiation. The authors compared film response to storage condition and time for Ultra-speed and Ektaspeed Plus films.

ABSTRACT. The precise source of circulating catecholamine (CA) at birth and their role in circulatory adaptation is unclear. In order to determine the contribution of increased postganglionic sympathetic nerve activity to the CA surge at birth, we induced complete sympathectomy in near term fetal lambs prior to delivery by giving 6-hydroxydopamine. Chronically catheterized fetal sheep received either 6-hydroxydopamine (n=5) or control infusion (n=6). Chemical sympathectomy was verified by tyramine infusion. Lambs were delivered at 142 ± 1 days of gestation and serial plasma CA, heart rate, blood pressure, cardiac output, blood gases, blood glucose, and free fatty acids, were measured before and for 4 h after delivery. Myocardial ß-adrenergic receptors and tissue CA concentration were determined following sacrifice. Baseline circulating norepinephrine (NE) values were lower in sympathectomized animals (183 ± 45 versus 373 ± 125 pg/ml, p<0.05) and epinephrine values were slightly higher (118 ± 89 versus 48 ± 1 pg/ml, NS). There was only a 2-fold increase in NE after cord cutting in sympathectomized animals while control animals had a 4-fold increase (peak NE values 354 ±121 versus 1305 ± 363 pg/ml respectively, p<0.001). Epinephrine increased significantly in both groups and there were no significant differences between sympathectomized and control animals. Heart rate and blood pressure rose abruptly in both groups after cord cutting and there were no significant differences. Cardiac output was similar in both groups. Blood glucose in sympathectomized animals was significantly higher than control before (p<0.005) and after (p<0.001, peak values 66 ± 15 versus 35 ± 12 mg/dl). Plasma free fatty acid levels rose after cord cutting and were similar in both groups. Tissue NE content in the hearts of sympathectomized animals were less than 5% of control (mean 1.92 ± 0.5%), verifying the completeness of sympathectomy in this tissue. Myocardial ß-adrenergic receptors were 229 ± 21 versus 199 ± 26 fmol/mg protein in sympathectomized and control animals, respectively. These results suggest that the majority of circulating NE seen at birth arises from postganglionic sympathetic neurons rather than adrenal medullary secretion. The comparable hemodynamic and metabolic homeostasis of the two groups underscores the importance of increased circulating adrenal epinephrine at birth.

Objective.CD44 is a surface glycoprotein widely distributed among different tissues. Malignant tumors may show a more complex pattern of CD44 expression, indicating a loss of splice control. The aim of our study is to investigate the expression of CD44 splice variants (CD44v) and its metastatic potential in clear cell carcinoma of the ovary.Methods.Twenty-two cases of clear cell carcinoma of the ovary were evaluated for CD44 standard form (CD44s) and splice variants: -4v, -6v, and -9v expression by immunocytochemistry.Results.Twenty-one primary ovarian tumors and 23 metastatic sites were available for evaluation. Eighteen of 21 (86%) of ovarian sections studied expressed CD44s; 15/21 (71%) expressed CD44-4v; 14/21 (67%) expressed CD44-6v; and 12/21 (57%) expressed CD44-9v. Of 23 metastatic sites evaluated, 87% expressed CD44s. In contrast, only 5 (22%) metastases had CD44-4v and CD44-6v expression and 8 (35%) had CD44-9v immunoreactivity. None of 10 normal contralateral ovaries expressed CD44s or any splice variants. In 2 cases we had tumor available from the primary surgery, and subsequent recurrences. Both recurrences showed decreased expression of CD44-4v and CD44-6v.Conclusions.Clear cell carcinoma of the ovary shows an abnormal pattern of CD44s expression and mRNA splicing when compared to the contralateral normal ovary in the same patient. Metastases of clear cell carcinoma show a downregulation in expression of some splice variants. Furthermore, we have data that suggest that as the tumors recur, CD44s and its isoforms are downregulated. Our results suggest that alternative mRNA splicing of CD44 may be important in the development of metastases from clear cell carcinoma of the ovary.

This study compares the diagnostic accuracy of caries detection using Ultra-speed (Eastman Kodak), Ektaspeed (Eastman Kodak) and Ektaspeed Plus (Eastman Kodak) films after they were developed in both new and used processing solutions. Ektaspeed Plus film provided significantly better diagnostic accuracy for small proximal-surface caries limited to the outer third of the dentin than did Ektaspeed film. Ektaspeed Plus film did not differ significantly from Ultra-speed film in aiding in the diagnosis of small carious lesions, and it maintained diagnostic accuracy in used processing solutions. Dentists can offer the X-ray dose-reducing technology of Ektaspeed Plus film to their patients and maintain consistently high diagnostic quality.