Persistent Peri-Ablation Blood-Brain Barrier Opening After Laser Interstitial Thermal Therapy for Brain Tumors

Purpose Laser interstitial thermal therapy (LITT) is a minimally invasive, image-guided, cytoreductive procedure to treat recurrent glioblastoma. This study implemented dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) methods and employed a model selection paradigm to localize and quantify post-LITT blood-brain barrier (BBB) permeability in the ablation vicinity. Serum levels of neuron-specific enolase (NSE), a peripheral marker of increased BBB permeability, were measured. Methods Seventeen patients were enrolled in the study. Using an enzyme-linked immunosorbent assay, serum NSE was measured preoperatively, 24 hours postoperatively, and at two, eight, 12, and 16 weeks postoperatively, depending on postoperative adjuvant treatment. Of the 17 patients, four had longitudinal DCE-MRI data available, from which blood-to-brain forward volumetric transfer constant (Ktrans) data were assessed. Imaging was performed preoperatively, 24 hours postoperatively, and between two and eight weeks postoperatively. Results Serum NSE increased at 24 hours following ablation (p=0.04), peaked at two weeks, and returned to baseline by eight weeks postoperatively. Ktrans was found to be elevated in the peri-ablation periphery 24 hours after the procedure. This increase persisted for two weeks. Conclusion Following the LITT procedure, serum NSE levels and peri-ablation Ktrans estimated from DCE-MRI demonstrated increases during the first two weeks after ablation, suggesting transiently increased BBB permeability.

Clinically useful tumor fluorescence greater than 24 hours after 5-aminolevulinic acid administration

Background:

5-aminolevulinic acid (5-ALA) is a valuable surgical adjuvant used for the resection of glioblastoma multiforme (GBM). Since Food and Drug Administration approval in 2017, 5-ALA has been used in over 37,000 cases. The current recommendation for peak efficacy and intraoperative fluorescence is within 4 h after administration. This narrow time window imposes a perioperative time constraint which may complicate or preclude the use of 5-ALA in GBM surgery.

Case Description:

This case report describes the prolonged activity of 5-ALA in a 66-year-old patient with a newly diagnosed GBM lesion within the left supramarginal gyrus. An awake craniotomy with language and sensorimotor mapping was planned along with 5-ALA fluorescence guidance. Shortly, after receiving the preoperative 5-ALA dose, the patient developed a fever. Surgery was postponed for an infectious disease workup which proved negative. The patient was taken to surgery the following day, 36 h after 5-ALA administration. Despite the delay, intraoperative fluorescence within the tumor remained and was sufficient to guide resection. Postoperative imaging confirmed a gross total resection of the tumor.

Conclusion:

The use of 5-ALA as an intraoperative adjuvant may still be effective for patients beyond the recommended 4-h window after initial administration. Reconsideration of current use of 5-ALA is warranted.

Abstract P405: A Time-Series Forecast Model to Assess Vital Sign Waveform Variability Prior to Vasospasm

Introduction: Symptomatic vasospasm (SV) is a complication of aneurysmal subarachnoid hemorrhage (aSAH) and can lead to cerebral infarction. Changes in vital trends, such as heart rate (HR) and mean arterial blood pressure (MAP), have been associated with SV in aSAH. Real-time assessment of instantaneous vital sign waveform data could improve detection of vital sign variability associated with vasospasm. However, no model using instantaneous waveform data exists to predict SV. We hypothesize that autoregressive integrated moving average (ARIMA) analysis, a time-series forecast model, is a useful approach to assess the variability of vital sign waveforms associated with SV.

Methods: In this small case-control study, vital signs of patients admitted to the neuroICU with aSAH were obtained using a software-based analytics platform, Sickbay. HR and MAP from 15 aSAH patients were continuously obtained from ECG and arterial line waveforms. Ten patients developed neurologic deficits attributed to angiographically-confirmed SV (Det). Five controls (Con) without SV were matched based on age. 3 Det and 3 Con were randomly selected for further analysis. For Det, waveforms were analyzed at 5-second intervals for 48 hours prior to clinical deterioration. For Con, waveforms were analyzed at a random 48-hour interval.

Results: Visually, MAP and not HR was more variable in Det than in Con patients (Figure). The ARIMA model plotted the forecasted-fit for each delta-variable waveform. The MAP confidence interval margins were significantly larger for Det patients compared to the Con patient. This trend was consistent across all other patients.

Conclusion: ARIMA is a useful tool to assess HR and MAP waveform variations prior to SV in aSAH. Larger studies are required to solidify this concept and further explore the combination of data analytics platform and ARIMA to predict neurological deterioration in SV.

Machine Learning Applications in the Neuro ICU: A Solution to Big Data Mayhem?

The neurological ICU (neuro ICU) often suffers from significant limitations due to scarce resource availability for their neurocritical care patients. Neuro ICU patients require frequent neurological evaluations, continuous monitoring of various physiological parameters, frequent imaging, and routine lab testing. This amasses large amounts of data specific to each patient. Neuro ICU teams are often overburdened by the resulting complexity of data for each patient. Machine Learning algorithms (ML), are uniquely capable of interpreting high-dimensional datasets that are too difficult for humans to comprehend. Therefore, the application of ML in the neuro ICU could alleviate the burden of analyzing big datasets for each patient. This review serves to (1) briefly summarize ML and compare the different types of MLs, (2) review recent ML applications to improve neuro ICU management and (3) describe the future implications of ML to neuro ICU management.

Mitochondrial retrograde signalling in neurological disease

Neuronal mitochondrial dysfunction causes primary mitochondrial diseases and likely contributes to neurodegenerative diseases including Parkinson's and Alzheimer's disease. Mitochondrial dysfunction has also been documented in neurodevelopmental disorders such as tuberous sclerosis complex and autism spectrum disorder. Only symptomatic treatments exist for neurodevelopmental disorders, while neurodegenerative diseases are largely untreatable. Altered mitochondrial function activates mitochondrial retrograde signalling pathways, which enable signalling to the nucleus to reprogramme nuclear gene expression. In this review, we discuss the role of mitochondrial retrograde signalling in neurological diseases. We summarize how mitochondrial dysfunction contributes to neurodegenerative disease and neurodevelopmental disorders. Mitochondrial signalling mechanisms that have relevance to neurological disease are discussed. We then describe studies documenting retrograde signalling pathways in neurons and glia, and in animal models of neuronal mitochondrial dysfunction and neurological disease. Finally, we suggest how specific retrograde signalling pathways can be targeted to develop novel treatments for neurological diseases. This article is part of the theme issue 'Retrograde signalling from endosymbiotic organelles'.

Pathomechanism Heterogeneity in the Amyotrophic Lateral Sclerosis and Frontotemporal Dementia Disease Spectrum: Providing Focus Through the Lens of Autophagy

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) constitute aggressive neurodegenerative pathologies that lead to the progressive degeneration of upper and lower motor neurons and of neocortical areas, respectively. In the past decade, the identification of several genes that cause these disorders indicated that the two diseases overlap in a multifaceted spectrum of conditions. The autophagy-lysosome system has been identified as a main intersection for the onset and progression of neurodegeneration in ALS/FTD. Genetic evidence has revealed that several genes with a mechanistic role at different stages of the autophagy process are mutated in patients with ALS/FTD. Moreover, the three main proteins aggregating in ALS/FTD, including in sporadic cases, are also targeted by autophagy and affect this process. Here, we examine the varied dysfunctions and degrees of involvement of the autophagy-lysosome system that have been discovered in ALS/FTD. We argue that these findings shed light on the pathological mechanisms in the ALS/FTD spectrum and conclude that they have important consequences both for treatment options and for the basic biomolecular understanding of how this process intersects with RNA metabolism, the other major cellular process reported to be dysfunctional in part of the ALS/FTD spectrum.

Mitochondrial stress causes neuronal dysfunction via an ATF4-dependent increase in L-2-hydroxyglutarate

Mitochondrial stress contributes to a range of neurological diseases. Mitonuclear signaling pathways triggered by mitochondrial stress remodel cellular physiology and metabolism. How these signaling mechanisms contribute to neuronal dysfunction and disease is poorly understood. We find that mitochondrial stress in neurons activates the transcription factor ATF4 as part of the endoplasmic reticulum unfolded protein response (UPR) in Drosophila We show that ATF4 activation reprograms nuclear gene expression and contributes to neuronal dysfunction. Mitochondrial stress causes an ATF4-dependent increase in the level of the metabolite L-2-hydroxyglutarate (L-2-HG) in the Drosophila brain. Reducing L-2-HG levels directly, by overexpressing L-2-HG dehydrogenase, improves neurological function. Modulation of L-2-HG levels by mitochondrial stress signaling therefore regulates neuronal function.

Mitochondrial retrograde signaling in the nervous system

Mitochondria generate the majority of cellular ATP and are essential for neuronal function. Loss of mitochondrial activity leads to primary mitochondrial diseases and may contribute to neurodegenerative diseases such as Alzheimer's and Parkinson's disease. Mitochondria communicate with the cell through mitochondrial retrograde signaling pathways. These signaling pathways are triggered by mitochondrial dysfunction and allow the organelle to control nuclear gene transcription. Neuronal mitochondrial retrograde signaling pathways have been identified in disease model systems and targeted to restore neuronal function and prevent neurodegeneration. In this review, we describe yeast and mammalian cellular models that have paved the way in the investigation of mitochondrial retrograde mechanisms. We then discuss the evidence for retrograde signaling in neurons and our current knowledge of retrograde signaling mechanisms in neuronal model systems. We argue that targeting mitochondrial retrograde pathways has the potential to lead to novel treatments for neurological diseases.

Field Test of a Hybrid Finite-Difference and Analytic Element Regional Model

Regional finite-difference models often have cell sizes that are too large to sufficiently model well-stream interactions. Here, a steady-state hybrid model is applied whereby the upper layer or layers of a coarse MODFLOW model are replaced by the analytic element model GFLOW, which represents surface waters and wells as line and point sinks. The two models are coupled by transferring cell-by-cell leakage obtained from the original MODFLOW model to the bottom of the GFLOW model. A real-world test of the hybrid model approach is applied on a subdomain of an existing model of the Lake Michigan Basin. The original (coarse) MODFLOW model consists of six layers, the top four of which are aggregated into GFLOW as a single layer, while the bottom two layers remain part of MODFLOW in the hybrid model. The hybrid model and a refined "benchmark" MODFLOW model simulate similar baseflows. The hybrid and benchmark models also simulate similar baseflow reductions due to nearby pumping when the well is located within the layers represented by GFLOW. However, the benchmark model requires refinement of the model grid in the local area of interest, while the hybrid approach uses a gridless top layer and is thus unaffected by grid discretization errors. The hybrid approach is well suited to facilitate cost-effective retrofitting of existing coarse grid MODFLOW models commonly used for regional studies because it leverages the strengths of both finite-difference and analytic element methods for predictions in mildly heterogeneous systems that can be simulated with steady-state conditions.

Lesions of uncertain malignant potential (B3) on core biopsy in the NHS Breast Screening Programme: is the screening round relevant?

INTRODUCTION

Most women who have screening mammography and undergo subsequent open biopsy following an indeterminate core biopsy result are eventually found to have benign disease. However, a significant number have malignant disease and the rate of malignancy in such cases may be influenced by various factors. This study examined the effect of the type of screening round (prevalent or incident) on the likelihood of breast cancer being present.

METHODS

A total of 199 women who had NHS breast screening mammograms and subsequent indeterminate (B3) core biopsy results followed by excision biopsy over an 11-year period in a single breast screening unit were reviewed.

RESULTS

The rate of malignancy following excision of a lesion graded as B3 on core biopsy was 21% for women in the prevalent screening round compared to 33% in subsequent rounds (Fisher's exact test, p=0.038).

CONCLUSIONS

The incidence of malignancy associated with a B3 core biopsy result appears to be related to the screening round in which the lesion is detected, being approximately 50% higher in the subsequent incident rounds compared to the initial prevalent round. This finding may be useful in formulating management plans for women who have an indeterminate biopsy result.

A hybrid finite-difference and analytic element groundwater model

Regional finite-difference models tend to have large cell sizes, often on the order of 1-2 km on a side. Although the regional flow patterns in deeper formations may be adequately represented by such a model, the intricate surface water and groundwater interactions in the shallower layers are not. Several stream reaches and nearby wells may occur in a single cell, precluding any meaningful modeling of the surface water and groundwater interactions between the individual features. We propose to replace the upper MODFLOW layer or layers, in which the surface water and groundwater interactions occur, by an analytic element model (GFLOW) that does not employ a model grid; instead, it represents wells and surface waters directly by the use of point-sinks and line-sinks. For many practical cases it suffices to provide GFLOW with the vertical leakage rates calculated in the original coarse MODFLOW model in order to obtain a good representation of surface water and groundwater interactions. However, when the combined transmissivities in the deeper (MODFLOW) layers dominate, the accuracy of the GFLOW solution diminishes. For those cases, an iterative coupling procedure, whereby the leakages between the GFLOW and MODFLOW model are updated, appreciably improves the overall solution, albeit at considerable computational cost. The coupled GFLOW-MODFLOW model is applicable to relatively large areas, in many cases to the entire model domain, thus forming an attractive alternative to local grid refinement or inset models.

Estimating recharge rates with analytic element models and parameter estimation

Quantifying the spatial and temporal distribution of recharge is usually a prerequisite for effective ground water flow modeling. In this study, an analytic element (AE) code (GFLOW) was used with a nonlinear parameter estimation code (UCODE) to quantify the spatial and temporal distribution of recharge using measured base flows as calibration targets. The ease and flexibility of AE model construction and evaluation make this approach well suited for recharge estimation. An AE flow model of an undeveloped watershed in northern Wisconsin was optimized to match median annual base flows at four stream gages for 1996 to 2000 to demonstrate the approach. Initial optimizations that assumed a constant distributed recharge rate provided good matches (within 5%) to most of the annual base flow estimates, but discrepancies of >12% at certain gages suggested that a single value of recharge for the entire watershed is inappropriate. Subsequent optimizations that allowed for spatially distributed recharge zones based on the distribution of vegetation types improved the fit and confirmed that vegetation can influence spatial recharge variability in this watershed. Temporally, the annual recharge values varied >2.5-fold between 1996 and 2000 during which there was an observed 1.7-fold difference in annual precipitation, underscoring the influence of nonclimatic factors on interannual recharge variability for regional flow modeling. The final recharge values compared favorably with more labor-intensive field measurements of recharge and results from studies, supporting the utility of using linked AE-parameter estimation codes for recharge estimation.

Surgical repair of rib fractures in 14 neonatal foals: case selection, surgical technique and results

REASONS FOR PERFORMING STUDY

Fractured ribs are encountered quite frequently in newborn Thoroughbred foals, often with fatal outcome. Surgical repair of fractures therefore requires consideration as a means of reducing mortality.

OBJECTIVES

To evaluate the repair of rib fractures using internal fixation techniques in foals at 2 different equine hospitals following similar diagnostics and case selection.

METHODS

The records of 14 foals that underwent internal fixation of fracture ribs were reviewed. Subject details, clinical presentation, diagnosis, surgical technique, post operative care and complications were recorded. Follow-up information was obtained in 7 foals.

RESULTS

The fractured ribs were reduced and stabilised using reconstruction plate(s), self-tapping cortical screws and cerclage wire in 12 cases, Steinmann pins and cerclage wires in 1 case and both techniques in 1 case. Not every rib was reduced on each case. Surgical reduction was performed on an average of 2 ribs, range 1-3 ribs in each foal. At the time of writing, 4 foals had been sold, one age 2 years was in training and 2 others died from unrelated causes.

CONCLUSIONS

Our data support the use of surgical stabilisation utilising reconstruction plates, self-tapping cortical screws and cerclage wire for selected cases of thoracic trauma in neonatal foals. The use of Steinmann pins may be suboptimal due to cyclic failure, implant migration and the potential for iatrogenic internal thoracic trauma.

POTENTIAL RELEVANCE

Foals with existing extensive internal thoracic trauma resulting from rib fracture(s), or the potential for such trauma, previously considered to have a guarded to poor prognosis for survival, may be successfully managed with internal fixation of selected fracture sites.

Survival analysis of posterior restorations using an insurance claims database

This study indicates that composite restorations do not last as long as amalgam restorations in posterior teeth. Dentists can use this information to better inform their patients when choosing restorative materials.

Delineating a recharge area for a spring using numerical modeling, Monte Carlo techniques, and geochemical investigation

Recharge areas of spring systems can be hard to identify, but they can be critically important for protection of a spring resource. A recharge area for a spring complex in southern Wisconsin was delineated using a variety of complementary techniques. A telescopic mesh refinement (TMR) model was constructed from an existing regional-scale ground water flow model. This TMR model was formally optimized using parameter estimation techniques; the optimized "best fit" to measured heads and fluxes was obtained by using a horizontal hydraulic conductivity 200% larger than the original regional model for the upper bedrock aquifer and 80% smaller for the lower bedrock aquifer. The uncertainty in hydraulic conductivity was formally considered using a stochastic Monte Carlo approach. Two-hundred model runs used uniformly distributed, randomly sampled, horizontal hydraulic conductivity values within the range given by the TMR optimized values and the previously constructed regional model. A probability distribution of particles captured by the spring, or a "probabilistic capture zone," was calculated from the realistic Monte Carlo results (136 runs of 200). In addition to portions of the local surface watershed, the capture zone encompassed areas outside of the watershed--demonstrating that the ground watershed and surface watershed do not coincide. Analysis of water collected from the site identified relatively large contrasts in chemistry, even for springs within 15 m of one another. The differences showed a distinct gradation from Ordovician-carbonate-dominated water in western spring vents to Cambrian-sandstone-influenced water in eastern spring vents. The difference in chemistry was attributed to distinctive bedrock geology as demonstrated by overlaying the capture zone derived from numerical modeling over a bedrock geology map for the area. This finding gives additional confidence to the capture zone calculated by modeling.

Scedosporium prolificans infection associated with arthritis and osteomyelitis in a horse

Scedosporium prolificans was associated with arthritis and degenerative osteomyelitis in a 6-year-old Thoroughbred racehorse. The horse was suspected to have an inflammatory lesion of the interosseous tendon, but treatment had resulted in only a minimal response. Shortly after diagnostic arthrocentesis of the left metacarpophalangeal joint was performed, the joint became severely swollen, and radiography of the area revealed lysis of the distal end of the third metacarpal bone, the proximal sesamoid bones, and the proximal end of the proximal phalanx. The horse did not respond to treatment and was euthanatized. At necropsy, severe erosive arthritis and degenerative osteomyelitis of the left metacarpophalangeal joint were seen. Swab specimens of the ulcerated lesions of the articular cartilage were submitted for microbial culture, and Scedosporium prolificans was isolated. Scedosporium prolificans is a newly recognized opportunistic fungal pathogen of humans and animals. In humans, S prolificans typically causes focal locally invasive infections that primarily involve musculoskeletal tissues; most often, infection is a result of penetrating trauma or surgical incision. In immunocompromised patients, fatal disseminated infection can occur. The fungus is resistant to almost all currently available antimycotic agents.

Career satisfaction and job characteristics of dental hygiene master's degree graduates

PURPOSE

The primary objectives of this study were to assess career and degree satisfaction as well as job characteristics of individuals graduating from programs awarding the master of science in dental hygiene or dental hygiene education degree.

METHODS

A pilot-tested questionnaire was mailed to all 252 individuals who graduated between 1980 and 1995 from eight dental hygiene master's degree programs (MSDH). The questionnaire included both closed- and open-ended items regarding career history/career path, career satisfaction, professional involvement, and opinions/perceptions about the graduate program the participant attended. Responses were analyzed using descriptive statistics and two-way tables.

RESULTS

After three complete mailings, the response rate was 69% (n = 174). The majority of respondents reported currently working approximately five days per week (54%), with 62% having annual salaries over $40,000. Eighty-six percent were satisfied overall with their career choices, although 30% stated that they would not pursue the same degree again.

CONCLUSION

Overall, graduates from MSDH programs are satisfied with their degree choice as well as the opportunities it has afforded them. These findings serve to expand the knowledge base of graduate dental hygiene education and of the graduates from these programs as well as provide suggestions for improvement to graduate dental hygiene programs.

Adjustment of the M-component of the DMFS index for prevalence studies of older adults

Cross-sectional studies of caries in older adults report a substantial number of missing teeth, making it difficult to estimate caries experience accurately. The goal of this study was to improve the method of estimating caries experience as expressed by the DMFS index in population groups with missing teeth. The adjustment was demonstrated with reference to the Piedmont 65+ Dental Study conducted on a random sample of 363 community-dwelling older adults in North Carolina who were followed for 5 years. These older dentate adults had a mean (+/-SE) of 11.7 +/- 0.5 teeth missing at baseline, 56.1 +/- 2.5 missing surfaces and a DMFS of 86.7 +/- 2.0. A predicted caries prevalence was determined from the DFS at 5 yrs plus the 5-yr DFS incidence and the baseline DFS of teeth lost during the study period. Then a formula was developed that would estimate the predicted caries prevalence as a function of the observed 5-yr DMFS. This formula provided a good estimation of caries prevalence at 5 yrs (DMFSadj) when compared with the predicted prevalence (paired t-test, p > 0.05), while prevalence was underestimated by the DFS and greatly overestimated by the traditional DMFS index. Subgroup analyses by race, sex, and periodontal status also indicated that the DMFSadj resulted in patterns of estimates similar to the predicted prevalence, while the DFS and the DMFS were likely to result in different findings. The DMFS from the time of tooth eruption also was adjusted using this formula. The resulting analyses of subgroup differences in caries were not different from the previous estimates based on the 5-yr historical data, indicating that the adjustment of all M surfaces avoids the biases inherent in the traditional DMFS and DFS indices. This study showed that predicted caries prevalence could be estimated by adjusting the M component of the DMFS. It appears that this adjustment formula can be used without obvious bias, but additional studies are needed to provide adjustment figures for populations with different caries prevalences.

Variations in the social impact of oral conditions among older adults in South Australia, Ontario, and North Carolina

Previous studies among older adults have demonstrated that oral disease frequently leads to dysfunction, discomfort, and disability. This study aimed to assess variations in the social impact of oral conditions among six strata of people aged 65 years and older: residents of metropolitan Adelaide and rural Mt Gambier, South Australia; residents of metropolitan Toronto-North York and non-metropolitan Simcoe-Sudbury counties, Ontario, Canada; and blacks and whites in the Piedmont region of North Carolina (NC), United States. Subjects were participants in three oral epidemiological studies of random samples of the elderly populations in the six strata. Some 1,642 participants completed a 49-item Oral Health Impact Profile (OHIP) questionnaire which asked about impacts caused by problems with the teeth, mouth, or dentures during the previous 12 months. The percentage of dentate people reporting impacts fairly often or very often was greatest among NC blacks for 41 of the OHIP items. Two summary variables of social impact were used as dependent variables in bivariate and multivariate least-squares regression analyses. Among dentate people, mean levels of social impact were greatest for NC blacks and lowest for NC whites, while people from South Australia and Ontario had intermediate levels of social impact (P < 0.01). Missing teeth, retained root fragments, root-surface decay, periodontal pockets, and problem-motivated dental visits were associated with higher levels of social impact (P < 0.05), although there persisted a two-fold difference in social impact across the six strata after adjustment for those factors Among edentulous people, there was no statistically significant variation in social impact among strata. The findings suggest that there are social and cultural factors influencing oral health and its social impact, and that those factors differ most between dentate blacks and whites in NC.

Salivary flow and risk of tooth loss in an elderly population

To investigate the relationship between salivary flow and tooth loss, 818 randomly selected dentate people aged 65 and older and living in North Carolina were administered a dental health interview and examination. A single paraffin-stimulated whole saliva sample of 3 ml was collected and flow rate was calculated. Three years later, 490 people were re-examined and tooth loss was determined. Thirty-five percent of the participants had salivary flow rates of 1.0 ml/min or less at baseline and 41% lost at least one tooth over the 3-yr follow-up. A logistic regression model controlling for marital status, race, and socioeconomic status showed that those with low salivary flow were more likely to lose at least one tooth during the 3-yr study period than were those with normal flow (odds ratio = 1.52, 95% CI = 1.02-2.24). Results from this representative study of community-dwelling older adults support the concept that compromised salivary flow is related to tooth loss. This finding should be considered in the management and prevention of oral diseases.

Five-year incidence rates and intraoral distribution of root caries among community-dwelling older adults

The 5-year incidence and intraoral distribution of decayed and filled root surfaces were evaluated in 379 black and 323 white residents of North Carolina aged 65 and older. During the period of study, approximately 39% of blacks developed at least one root DFS compared with 52% for whites (Wald X(2) test, p = 0.062). When the results were calculated using the net root DFS increment, blacks did not have significantly higher rates than whites over the 5-year study period (0.52 surfaces/person versus 0.42 surfaces/person, Survey Regression, n = 363, p = 0.708). However, for blacks, the 5-year incidence density rate of root DFS was 0.26 per 60 surface-months at risk, and for whites the rate was 0.19 new root DFS per 60 surface-months (incidence density ratio = 1.33, 95% CI = 1.01-1.76, p = 0.047). Intraoral distribution patterns for root caries incidence revealed that the approximal surfaces of the anterior teeth were involved most frequently, particularly in the mandible and maxilla in whites, followed in decreasing order by the buccal surfaces of the lower anteriors and the mesial surfaces of the upper anteriors in blacks. Although root caries incidence rates were obviously low, there were significant differences in the occurrence of caries between blacks and whites. The pattern of occurrence was similar for both races with root surface disease being concentrated in the approximal surfaces of the anterior teeth in a small proportion of affected individuals, with whites presenting more filled root increments than blacks. These findings suggest a need for more caries treatment in blacks and increased monitoring of this population since they are at a higher risk for root caries.

Differences between racial groups in the impact of oral disorders among older adults in North Carolina

OBJECTIVES

This study investigated variations in impact of oral disorders between older black adults and older white adults living in North Carolina.

METHODS

Using the Oral Health Impact Profile (OHIP) questionnaire, 440 participants aged 70 and older provided data on their perceptions of the impact of oral disease on aspects of their lives during the previous 12 months.

RESULTS

For 22 of the 49 items queried in the OHIP questionnaire, older blacks reported more frequent impact than older whites (P < .05). For none of the OHIP items did whites report more frequent impact. The impacts reported were diverse and included items reflecting pain, physical disability, psychological disability, and social disability. When the number of items occurring fairly often or very often were summed for dentate participants, blacks reported more items than did whites (3.7 vs 1.1, P < .0001). This difference decreased to 2.7 vs 2.0 (P < .346) after controlling statistically for greater mean periodontal pocket depth, more unreplaced missing teeth, and more episodic dental visits among blacks.

CONCLUSIONS

Older dentate blacks reported more impact from oral problems than older dentate whites. The differences in reported impact likely are linked to differences in oral status and dental visit history between these two racial groups in North Carolina.

Unilateral choanal atresia in a foal

A 4-month-old Thoroughbred foal was examined because of a history of exercise intolerance and lack of airflow from the right nostril since birth. Endoscopy of the airways revealed complete membranous obstruction of the right nasal passage at the level of the nasopharynx and marked narrowing of the caudal aspect of the right ventral meatus. Unilateral choanal atresia was diagnosed. Laser ablation of the obstructing tissues was attempted through a videoendoscope. Scar tissue occluded the right nasal passage at follow-up examination 7 weeks later. Intranasal resection, using laparoscopic instruments, was then performed, and a nasal stent was maintained for 2 weeks after surgery. At 1 year of age, the foal was reported to have decreased airflow from the right nares and excessive respiratory noise during exercise. Atresia of the choanae in horses usually is bilateral and, therefore, life-threatening and detectable at birth. Unilateral choanal atresia may not be suspected until later, but should be considered in horses with decreased or no airflow from 1 naris.

Physicochemical properties, pharmacokinetics, and biodistribution of gadoteridol injection in rats and dogs

RATIONALE AND OBJECTIVES

The physicochemical properties of gadoteridol, a macrocyclic nonionic gadolinium complex, were studied together with its pharmacokinetics and biodistribution in rats and dogs.

METHODS

Studies in rats were conducted after single intravenous injections at 0.1 or 0.35 mmol/kg using 153Gd-labeled gadoteridol or with seven daily doses of 0.1 mmol/kg to examine the levels of residual gadolinium in organs. Nonradioactive biodistribution and excretion studies were performed in dogs following injection at 0.1 mmol/kg.

RESULTS

After injection, the dose was rapidly cleared from rat blood and excreted such that more than 90% of the dose appeared in the urine within 4 hr of injection. At 7 and 14 days postinjection, only extremely low levels of gadolinium were observed in liver and bone; these levels were two to eight times lower than the levels reported after the injection of gadopentetate dimeglumine.

CONCLUSION

The extracellular distribution and rapid urinary excretion of gadoteridol is in agreement with data obtained with other gadolinium-containing chelates used as intravascular magnetic resonance imaging contrast agents. Differences observed in the long-term retention of gadolinium between gadoteridol and gadopentetate dimeglumine were consistent with the reported greater in vivo resistance to transmetallation of gadolinium macrocycles compared with the linear gadolinium chelate molecules.

Risk factors for dental fluorosis in pediatric dental patients

OBJECTIVES

Concerns have been raised recently about whether a substantial amount of dental fluorosis is resulting from the increased use of fluoride from various sources. The purposes of this study were to determine the prevalence and severity of dental fluorosis in a sample of pediatric patients seeking dental treatment in a university pediatric dental clinic and to evaluate sources of fluoride as risk factors for dental fluorosis.

METHODS

A convenience sample of 157 children aged 8 to 17 years were examined for dental fluorosis using the Tooth Surface Index of Fluorosis (TSIF). Fluoride history questionnaires assessing previous exposure to fluoride during the first eight years of life were completed by the children's parents. Fluoride exposures were compared among 54 cases and 54 matched controls using a case-control retrospective design.

RESULTS

Fluorosis was found in 72 percent of the children, but was generally quite mild. The risk of fluorosis was significantly greater for children who had greater exposure to fluoridated water and who used larger amounts of fluoridated toothpaste up to age eight.

CONCLUSIONS

This study provided evidence that increased use of fluoride toothpaste may be a risk factor for dental fluorosis. The results suggest prudent use of dentifrice by young children to minimize the risk of fluorosis.

Eighteen-month incidence of tooth loss among older adults in North Carolina

This study investigated tooth loss in North Carolina adults 65 years of age or older. A random sample of 335 Blacks and 284 Whites participated in dental examinations and interviews at baseline and again after 18 months. Blacks were more likely than Whites to lose at least one tooth (36% vs 19%), and they lost more teeth on average (1.0 vs 0.4). Several oral disease conditions and symptoms were related to tooth loss, but many other hypothesized factors were not. Risk models were inconclusive in the identification of factors related to risk of tooth loss.

Three-year root caries incidence and risk modeling in older adults in North Carolina

OBJECTIVES

The purposes of this study were to describe the incidence of root caries and to identify its risk factors in a representative sample of older adults.

METHODS

Root caries incidence was estimated and multivariate risk assessment models were developed to identify predictors for root caries in a three-year follow-up study of 234 black and 218 white noninstitutionalized adults aged 65 and older residing in North Carolina.

RESULTS

During the observation period, 29 percent of blacks developed root caries, compared to 39 percent of whites (P < .05). The mean net DFS increment per person was 0.55 +/- 0.13 root surfaces for blacks vs 0.80 +/- 0.21 for whites (P > .32). Multivariate logistic regression analysis indicated that blacks wearing a partial denture, having some root fragments, having an average gingival recession > or = 2 mm, and being free of P. intermedia were at greater risk for developing new root caries. The model for whites showed that retired people with their most severe gingival recession > or = 4 mm, an average probing pocket depth > or = 2 mm, and taking antihistamines were more likely to develop new lesions.

CONCLUSIONS

These findings suggest that older blacks had less risk of root caries than whites, and in both groups indicators of poor periodontal status increased the risk of root caries.

Intraperitoneal use of sodium carboxymethylcellulose in horses undergoing exploratory celiotomy

The effect of intraperitoneal sodium carboxymethylcellulose (SCMC) administration on clinical outcome and survival was evaluated in horses undergoing exploratory celiotomy for acute gastrointestinal disease. Comparison of variables was made retrospectively between 44 horses that had SCMC and 92 horses (controls) not treated with SCMC. Mean age, body weight, heart rate, packed cell volume and plasma total protein of horses at admission, and convalescent period were not significantly different between control and SCMC groups. No significant differences were noted between control horses and SCMC horses with respect to incisional infection, hernia formation, recurrent episodes of colic, clinical outcome, and long-term survival (> 6 months). Seventy-six (83%) control horses and 34 (77%) SCMC horses survived long-term. Seventy (76%) control horses and 30 (68%) SCMC horses survived without complications and returned to their previous use. These results suggest that intraperitoneal use of SCMC does not adversely affect abdominal incisional wound healing, clinical outcome or long-term survival, however, the efficacy of SCMC in prevention of postoperative intestinal adhesions in horses requires further investigation.

Three-year tooth loss among black and white older adults in North Carolina

The distribution and determinants of tooth loss in older adults are poorly defined, especially in Blacks, who have been underrepresented in previous studies. This study investigated, epidemiologically, the distribution and predictors of tooth loss in elder Blacks and Whites by following a random sample of older adults in North Carolina for three years. It was hypothesized that Blacks would be at greater risk of tooth loss and would have different risk factors for tooth loss. Data from 263 Blacks and 228 Whites were collected by dental examinations and interviews conducted in the participants' homes. During the three-year follow-up, 53% of Blacks and 29% of Whites lost at least one tooth. Blacks lost 13% of their remaining teeth compared with 4% for Whites. Logistic regression models showed that factors related to tooth loss for Blacks were: more S. mutans in stimulated saliva, deeper periodontal pockets, more P. intermedia in subgingival plaque, high blood pressure, limited help from others, and few symptoms of depression. For Whites, significant factors were: more lactobacilli in stimulated saliva, history of current oral pain at baseline, more alcohol consumption, no history of past use of calcium or xerostomic medications, higher income, lower occupational prestige, and increased numbers of negative life events. This study showed that older Blacks were at greater risk of tooth loss than older Whites. For both races, factors such as oral bacteria, periodontal conditions, oral symptoms, and psychosocial and economic factors are related to increased risk of tooth loss.

Distribution of primary tooth caries in first-grade children from two nonfluoridated US communities

In a prospective longitudinal study, 1099 first grade children from Aiken, South Carolina, and 1086 children from Portland, Maine, were examined annually for 3 years. Caries prevalence and dmfs incidence were determined. The mean dmfs in Portland children was 2.9. In Aiken, white children had a mean dmfs of 8.4, and black children had a mean dmfs of 10.2. The mean 3-year primary tooth caries increment was 1.5 surfaces in the Portland cohort 3.3 surfaces in the Aiken white cohort and 2.8 surfaces in the Aiken black cohort. These increments were divided evenly between interproximal and fissure surfaces. Twenty percent of the children in Portland had 75% of the caries; in Aiken, 20% of the children had 60% of the caries. This distribution suggests a high-risk group that could be targeted for aggressive caries prevention efforts if risk factors can be identified.

Repair of fractures of the distal aspect of the radius in two horses

Fractures of the distal radius in two horses were repaired by open reduction and interfragmentary compression using screws placed in a lag fashion. One horse had a complete oblique fracture of the medial aspect of the epiphysis of the distal radius and was sound for riding 32 months after surgery. The other horse had an open spiral comminuted fracture with medial displacement of the distal radial fragment. Laminitis developed in the contralateral limb and this horse was euthanatized 5 weeks after surgery.

Effects of acetylpromazine, xylazine, and vertical load on digital arterial blood flow in horses

Palmar digital arterial blood flow was measured in 6 conscious, standing horses, using surgically placed perivascular ultrasonic flow probes. The effects of 2 dosages of xylazine (0.55 and 1.1 mg/kg of body weight) and of 3 dosages of acetylpromazine (0.01, 0.02, and 0.04 mg/kg), as well as the effect of vertical load, on digital blood flow were evaluated. Intravenous administration of xylazine induced a significant (P < 0.05), transient decrease in digital blood flow. Intravenous administration of acetylpromazine induced a significant (P < 0.05), prolonged increase in digital blood flow. Correlation between vertical load and digital blood flow was found. The results of this study indicate that use of acetylpromazine may be beneficial in clinical treatment of horses with reduced digital blood flow. Xylazine, on the other hand, may exacerbate ischemic conditions of the digit and should be used with caution.

Eighteen-month coronal caries incidence in North Carolina older adults

In this longitudinal study of a random sample of North Carolinians over the age of 65 and living in their homes, 325 blacks and 280 whites were examined and interviewed 18 months after baseline examinations. Coronal caries incidence was greater among whites than blacks. The increment due to teeth becoming root fragments were similar for both races; however, there were more newly crowned teeth among whites. Newly crowned surfaces were not used as part of the caries increment in logistic regression models to investigate potential risk predictors. For blacks, caries development over the 18-month period was associated with a higher lactobacillus score and more coronal caries at baseline, more previously filled coronal surfaces, and lack of active membership in clubs or other groups. For whites, having no self-reported tooth sensitivity, having a lower socioeconomic index score, taking antihistamine medications at baseline, and having the perception of more problems after the age of 40 than before were all associated with the development of coronal caries.

Conservative management of femoral diaphyseal fractures in four foals

Femoral fractures in young horses can occur as a result of severe trauma and generally have a poor prognosis despite treatment. Four young horses with femoral diaphyseal fractures were managed with conservative treatment consisting of prolonged rest, analgesics, hind limb support, and corrective farriery. A favorable outcome in the form of pasture soundness with potential for limited athletic usefulness was obtained in 3 out of the 4 cases. This report supports the use of conservative treatment of selected diaphyseal femoral fractures in young horses.

The distribution and interrelationship of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, and BANA scores among older adults

In a random sample of subgingival dental plaque samples from 375 blacks and 300 whites aged 65 and older, immunofluorescence assays for 3 target pathogens including Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia, and BANA enzyme analysis were carried out. Blacks had significantly greater proportions of P. gingivalis and P. intermedia in their subgingival plaque and had significantly higher BANA scores. These assay results were investigated for concordance with each other and with 2 cariogenic salivary bacteria, Streptococcus mutans and lactobacilli. In general for both races, the periodontal pathogens were more likely to occur in combination with each other than with either S. mutans or lactobacilli. P. gingivalis and P. intermedia were more frequently associated with each other than with A. actinomycetemcomitans. There was a significant negative concordance between BANA and A. actinomycetemcomitans in whites and a significant positive concordance between BANA and P. intermedia in blacks.

Understanding the value of teeth to older adults: influences on the quality of life

Understanding the value of teeth to older adults is important in marketing dental services and motivating patients to care for their teeth. The authors surveyed more than 1,000 older adults in North Carolina to determine how teeth affect the quality of their lives.

A retrospective evaluation of laminitis in horses

Case records of 202 horses treated for laminitis were reviewed with the intent of determining the long-term outcome and correlating this with digital radiographic findings and with the degree of pain associated with the laminitis. At long-term follow-up 57 horses had returned to athletic soundness (Group 1), 20 horses were intermittently lame (Group 2), 19 horses had permanent severe lameness (Group 3), 97 were dead (Group 4), and 9 were lost to follow up. Using simple regression analysis, functional outcome did not correlate with the degree of rotation (R2 = 0.004) or the presence of distal displacement (R2 = 0.139). Functional outcome did correlate with the clinical grade of laminitis (R2 = 0.504). Horses in Group 1 had significantly less distal phalangeal rotation (5.89 +/- 6.48 degrees) than did horses in Group 2 (11.10 +/- 8.19) and Group 3 (14.50 +/- 10.80), but were not significantly different from Group 4 horses (7.49 +/- 6.57). Of 96 surviving horses, 23 had evidence of distal displacement compared with 54 of 97 non-survivors. Based on these results, horses that develop distal displacement of the distal phalanx are more likely to die than are horses without distal displacement; however, the presence or absence of distal phalangeal displacement and the degree of distal phalangeal rotation cannot be used to predict the outcome of a horse with laminitis. Clinical assessment is a more reliable means of determining the final outcome and should be given precedence over radiographic findings.

Assessing dental practice quality by evaluating radiology items

The DEMCAD dental office assessment instrument was developed to evaluate practice quality using Donebedian's quality assessment model of structure, process, and outcome. This previously validated instrument takes about six hours to complete. Subsequent analysis was undertaken to determine whether an abbreviated office assessment based on the evaluation of radiology items was sufficiently sensitive, specific, and practical to be used as a screening instrument for identifying dental offices with very low evaluation scores. Data for this analysis were obtained from 300 volunteer general dental practices evaluated in the field testing of the DEMCAD instrument. The nine radiology structure items predicted very poorly the overall structure scores. However, 13 radiology process items predicted overall process scores quite accurately. Four of the 13 radiology process items (periodontal diagnoses recorded, interdental bone shown on x-rays, caries diagnoses recorded, and current x-rays mounted) produced a combined R2 of .58. These four radiology variables predicted the 10 percent of the dental practices with the lowest overall process score with 87 percent sensitivity and 93 percent specificity. This analysis showed that an abbreviated dental practice process quality assessment using oral radiology items in an audit of patients' records may be feasible as a screening test for dental office assessment.

Streptococcus mutans, lactobacilli, and caries experience in older adults

This study investigated salivary levels of Streptococcus mutans, lactobacilli, and caries experience in a random sample of 448 black and 362 white older dentate adults living in North Carolina. Significant proportions of the participants had stimulated salivary flow rates less than 1.0 mL/min, salivary buffering capacity less than 4.0, S. mutans levels of 10(5) cfu/mL or more in stimulated whole saliva, or lactobacilli levels of 10(5) cfu/mL or more. Each of these factor levels could be considered, on a clinical basis, to increase caries risk. In general, people with higher levels of S. mutans or lactobacilli had more untreated coronal and root caries, but not greater total caries experience.

Tension-band wiring and lag screw fixation of a transverse, comminuted fracture of a patella in a horse

A transverse, comminuted fracture of the patella was treated surgically by combining tension-band wiring and lag-screw fixation in a horse. Partial patellectomy or smaller detached fragments of the patella was performed. Satisfactory healing of the fracture was evident 10 weeks after surgery, and there were no complications. Implants were not removed. The horse was sound at a trot 4 months after surgery and was used for pleasure riding 8 months later.

Sutured end-to-end and stapled side-to-side jejunal anastomoses in the horse

Hand sutured end-to-end (EE) and stapled side-to-side (SS) small intestinal anastomoses were performed in 10 healthy adult horses. In five SS anastomoses, staple lines on the blind ends of the jejunum were inverted (SSI) and in five they were not (SSNI). Five EE anastomoses were sutured with polydioxanone and five were sutured with polyglyconate. All horses were euthanatized on day 30. Intra-abdominal adhesions were graded (0-4), and stomal areas were calculated from contrast radiographs made with the bowel distended. Histopathology scores for the anastomoses were based on the degree of inflammation (0-3), fibrosis (0-3), and alignment and healing of intestinal layers (0-3). Mean surgery times +/- standard deviations for EE, SSI, and SSNI techniques were 33.9 +/- 5.4, 36.2 +/- 5.6, and 29.6 +/- 5.9 minutes, respectively. Mean and median stomal areas were 9.4 +/- 5.5 and 8.9 cm2 for EE anastomoses and 17.2 +/- 16.5 and 12.1 cm2 for SS anastomoses. Intra-abdominal adhesions developed in three horses, one of which had clinical signs of colic. Mean histopathology scores for EE and SS anastomoses were 4.8 +/- 2.0 (median = 5) and 4.4 +/- 1.8 (median = 4), respectively. There were no statistically significant differences in surgery times, intra-abdominal adhesion scores, stomal areas, or histopathology scores between small intestinal EE and SS anastomoses in these horses.

Effect of examining half the teeth in a partial periodontal recording of older adults

Limited evidence to date has suggested that half-mouth examinations can be used in epidemiological surveys for accurate estimation of the prevalence of periodontal conditions. This study investigated the accuracy and efficiency of half-mouth periodontal examinations of mesial and buccal sites by comparing whole-mouth findings from those sites with findings that would have been obtained by examining only two randomly selected quadrants of teeth in three older dentate adult populations: 263 whites in Iowa, 309 whites in North Carolina, and 384 blacks in North Carolina. Mean half-mouth scores for gingival recession, pocket depth, attachment loss, and Extent and Severity Index were almost identical to those of mean whole-mouth scores, with correlations between means exceeding 0.93. However, the proportions of the population having selected levels of moderate or severe periodontal disease in mesial and buccal sites were underestimated by as much as 13%. This study showed that half-mouth examinations can be accurate and efficient in estimating mean periodontal measures, but may underestimate the prevalence of periodontal conditions.

Repair of a ruptured calcaneal tendon by transposition of the tendon of the peroneus longus muscle in a goat

Traumatic rupture of the calcaneal tendon was diagnosed in a 3-year-old female goat. Clinical features included tarsal hyperflexion and diffuse swelling in the area of the calcaneal tendon. Surgical repair consisted of debridement of devitalized tissue and transposition of the tendon of the peroneus longus muscle to bridge the calcaneal tendon defect. Adequate postoperative immobilization followed by gradual introduction of tendon loading allowed a favorable outcome.

Intracranial trauma associated with extraction of a temporal ear tooth (dentigerous cyst) in a horse

Heterotopic polyodontia is typically associated with a sinus and a fistulous tract with a secreting membrane which extends to an ectopic tooth attached to the temporal bone. Recommendations for treatment include complete excision of the tract, the dental component, and the lining of the alveolar socket. Iatrogenic cerebral trauma was encountered during surgical extraction of an ectopic tooth. At post-mortem examination a second ectopic tooth was found compressing the right side of the cerebellum.

Five-year incidence of tooth loss in Iowans aged 65 and older

The prevalence of missing teeth has been described for US adults, but little is known about the incidence of tooth loss in any segment of the population. This study investigated the 5-yr incidence of tooth loss in a random sample of Iowans aged 65 yr and older residing in two rural counties. These people had an average of 20 teeth at baseline and approximately 40% lost at least one tooth in the subsequent 5 yr. The incidence of tooth loss was highest for mandibular molars and lowest for mandibular canines. Men were more likely than women to lose teeth. Although we were able to identify a number of statistically significant potential risk factors for tooth loss, the multivariate models that incorporated all these factors were not good predictors of which people were at highest risk for tooth loss.

Mid-metacarpal deep digital flexor tenotomy in the management of refractory laminitis in horses

Deep digital flexor tendon transection at the mid-metacarpus was performed in 20 horses with severe acute or chronic laminitis that was not responsive to conventional treatment. Sixteen horses improved within 72 hours, one horse worsened, and two horses were unaffected by the surgery. Eleven horses survived less than 1 month after surgery and six horses survived longer than 6 months. Three horses surviving longer than 6 months have remained lame and no horse has returned to athletic performance. Transection of the deep digital flexor tendon at the mid-metacarpus may decrease the pain associated with the acute refractory stage of laminitis and may be useful as an immediate salvage procedure; however, despite the early clinical improvement observed after tenotomy, the survival rate of affected horses may not be altered.