Howard C. Tenenbaum

University of Toronto

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Michael B. Goldberg

University of Toronto

Michael Glogauer

Princess Margaret Cancer Centre

Amir Azarpazhooh

Mount Sinai Hospital

Christopher A. McCulloch

University of Toronto

Noah Fine

University Health Network

Bruce V. Freeman

Mount Sinai Hospital

David Mock

Mount Sinai Hospital

Herenia P. Lawrence

University of Toronto

B. Sukhu

University of Central Florida

Massieh Moayedi

University of Toronto

Cooperative Institutions

University of Toronto

280

Mount Sinai Hospital

John Wiley & Sons (United States)

Nova Southeastern University

Liechtenstein Institute

University Health Network

Inserm

Lunenfeld-Tanenbaum Research Institute

Université de Strasbourg

St. Michael's Hospital

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Perceived helplessness is associated with individual differences in the central motor output system

European Journal of Neuroscience (2012)

Tim V. Salomons Massieh Moayedi Irit Weissman‐Fogel Michael B. Goldberg Bruce V. Freeman

Abstract Learned helplessness is a maladaptive response to uncontrollable stress characterized by impaired motor escape responses, reduced motivation and learning deficits. There are important individual differences in the likelihood of becoming helpless following exposure to uncontrollable stress but little is known about the neural mechanisms underlying these individual differences. Here we used structural MRI to measure gray and white matter in individuals with chronic pain, a population at high risk for helplessness due to prolonged exposure to a poorly controlled stressor (pain). Given that self‐reported helplessness is predictive of treatment outcomes in chronic pain, understanding such differences might provide valuable clinical insight. We found that the magnitude of self‐reported helplessness correlated with cortical thickness in the supplementary motor area (SMA) and midcingulate cortex, regions implicated in cognitive aspects of motor behavior. We then examined the white matter connectivity of these regions and found that fractional anisotropy of connected white matter tracts along the corticospinal tract was associated with helplessness and mediated the relationship between SMA cortical thickness and helplessness. These data provide novel evidence that links individual differences in the motor output pathway with perceived helplessness over a chronic and poorly controlled stressor.

Learned helplessness

Stressor

10.1111/j.1460-9568.2012.08048.x

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Citations (54)

Effects of the bite splint 15-day treatment termination in patients with temporomandibular disorder with a clinical history of sleep bruxism: a longitudinal single-cohort study

Oral Surgery Oral Medicine Oral Pathology and Oral Radiology (2012)

Daniela Rehm Vivian Chiada Mainieri Aline Cristina Saueressig Patrícia Krieger Grossi Eduardo Rolim Teixeira

Sleep Bruxism

Depression

Longitudinal Study

10.1016/j.oooo.2012.06.009

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Citations (15)

Dexamethasone effects on induction of neoplastic transformation by Fujinami sarcoma virus in an in vitro chick embryo periosteal model for osteosarcoma.

PubMed (1988)

Catalena Birek Tony Pawson C McCulloch Howard C. Tenenbaum

Recently we have developed a model in vitro system for the study of factors regulating the histogenesis of osteosarcoma. In this system, Fujinami sarcoma virus (FSV) induces osteosarcomatous changes such as increased cell proliferation and altered patterns of bone and nonmineralized matrix (osteoid) formation. Such changes can be quantitated at the individual cell level, by computer-assisted morphometry. Here we report on the effects of dexamethasone (DEX) on FSV-induced neoplastic transformation and osteogenesis in chick embryonic periosteum cultures, as reflected by a series of histopathological parameters. Most significantly, it was found that compared to 10(-9) M DEX treated cultures, in 10(-7) M DEX pretreated cultures, the bone/osteoid ratio was increased due to a relative increase in the area of bone and a decrease in the area of osteoid. The number of [3H]thymidine-labeled cells decreased significantly, while the proportion of alkaline phosphatase positive cells increased. Double-label immunohistochemistry (with anti-P140gag-fps) and histochemistry for alkaline phosphatase activity was performed, to demonstrate production of the oncogene-encoded protein, and osteoblastic differentiation, respectively. In an in vitro transformation assay single cells derived from 10(-9) M DEX treated cultures formed a significantly higher number of colonies than those obtained from 10(-7) M DEX pretreated cultures. Taken together, the data indicate that in the chick embryonic periosteum culture system, pretreatment with 10(-7) M DEX inhibits the ability of FSV to induce neoplastic transformation. This effect is probably the result of DEX-induced cell differentiation, prior to infection with FSV.

Osteoid

Histogenesis

Periosteum

Neoplastic transformation

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Citations (6)

Evaluation of temporomandibular joint internal derangement.

PubMed (1993)

G. Romanelli Richard Harper David Mock Michael J. Pharoah Howard C. Tenenbaum

The incidence of internal derangement of the temporomandibular joint has been documented in patients with temporomandibular disorders. However, the detection and diagnosis of a displacement of the temporomandibular joint disc in relation to internal derangement is not always accurate, and it varies according to the method of examination. A prospective clinical investigation of 26 patients (45 temporomandibular joints) with signs and symptoms of temporomandibular joint pain and dysfunction was completed to examine the accuracy of clinical examination, sagittal recording device tracings, arthrography, and magnetic resonance imaging in detecting internal derangement in the temporomandibular joint. A group of 16 asymptomatic control subjects (32 temporomandibular joints) was examined for the presence of internal derangement by the methods under consideration. Incidence of bilateral internal derangement in the temporomandibular joints of the symptomatic patients was also assessed. Findings obtained through clinical examination and sagittal recording device tracings agreed most often with the arthrographic findings of internal derangement. Magnetic resonance imaging often failed to detect the presence of arthrographically detected internal derangement. Internal derangement was identified bilaterally in a significant number of patients, despite the absence of bilateral symptoms. This incidence varied according to the technique used. In the control group, 9% of the temporomandibular joints that had been assessed as normal according to clinical examination and sagittal recording device tracings were found to have internal derangement according to magnetic resonance imaging.

Derangement

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Citations (38)

Abnormal cortical activity in patients with temporomandibular disorder evoked by cognitive and emotional tasks

Pain (2010)

Irit Weissman‐Fogel Massieh Moayedi Howard C. Tenenbaum Michael B. Goldberg Bruce V. Freeman

Patients with temporomandibular disorder (TMD) perform poorly in neuropsychological tests of cognitive function. These deficits might be related to dysfunction in brain networks that support pain and cognition, due to the impact of chronic pain and its related emotional processes on cognitive ability. We therefore tested whether patients with TMD perform poorly in cognitive and emotion tasks and whether they had abnormal task-evoked brain activity. Seventeen female subjects with nontraumatic TMD and 17 age-matched healthy female subjects underwent functional magnetic resonance imaging while performing counting Stroop tasks comprising neutral words, incongruent numbers, or emotional words, including TMD-specific words. Group differences in task-related brain responses were assessed. Connectivity between 2 pairs of coupled brain regions during the cognitive and emotional tasks (prefrontal-cingulate and amygdala-cingulate) was also examined. The patients had sluggish Stroop reaction times for all Stroop tasks. Furthermore, compared to controls, patients showed increased task-evoked responses in brain areas implicated in attention (eg, lateral prefrontal, inferior parietal), emotional processes (eg, amygdala, pregenual anterior cingulate), motor planning and performance (eg, supplementary and primary motor areas), and activation of the default-mode network (medial prefrontal and posterior cingulate). The patients also exhibited decoupling of the normally correlated activity between the prefrontal and cingulate cortices and between the amygdala and cingulate cortex. These findings suggest that the slow behavioral responses in idiopathic TMD may be due to attenuated, slower, and/or unsynchronized recruitment of attention/cognition processing areas. These abnormalities may be due to the salience of chronic pain, which inherently requires attention. Sluggish performance in cognitive and emotional interference tasks in patients with nontraumatic temporomandibular disorder is associated with pronounced and unsynchronized task-evoked fMRI brain responses.

Stroop effect

Cingulate cortex

Posterior cingulate

10.1016/j.pain.2010.10.046

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Citations (135)

Dental treatment and employment outcomes among social assistance recipients in Ontario, Canada

Health Policy (2016)

Sonica Singhal Muhammad Mamdani Andrew Mitchell Howard C. Tenenbaum Gerald Lebovic

Social Assistance

10.1016/j.healthpol.2016.08.011

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Citations (14)

Locally Inducing High Expression of Tissue Nonspecific Alkaline Phosphatase Might Regulate Scar Tissue Maturation

Plastic & Reconstructive Surgery (1995)

M. Hui Howard C. Tenenbaum

Samuel Lunenfeld Research Institute at Mount Sinai Hospital 600 University Avenue Room 984 Toronto, Ontario M5G 1X5 Canada

Scar tissue

10.1097/00006534-199501000-00052

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Citations (2)

Clinical management of avulsed permanent incisors using Emdogain: initial report of an investigation.

PubMed (2000)

David J. Kenny Edward J. Barrett Douglas H. Johnston Michael Sigal Howard C. Tenenbaum

The enamel matrix derivative Emdogain was recently approved for clinical use in a number of countries, including Canada. It has been shown to stimulate regeneration of periodontal ligament following periodontal surgery in adults. This paper reviews pertinent clinical and laboratory studies of Emdogain and describes the protocol and methods used for a longitudinal outcome study of replantation of avulsed permanent incisors in children and adolescents. Application of these methods is described in an illustrative case report of Emdogain use. This paper is meant to inform clinicians and guide those who are instituting similar investigations.

Enamel matrix derivative

Periodontal fiber

Tooth Replantation

Tooth Avulsion

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Citations (42)

Porphyromonas gingivalis-impaired innate immune response via NLRP3 proteolysis in endothelial cells

Innate Immunity (2014)

Olivier Huck R. Elkaïm Jean‐Luc Davideau Howard C. Tenenbaum

Porphyromonas gingivalis ( Pg) is involved in the link between periodontal diseases and atherosclerosis worsening. In periodontal cells, Pg modifies IL-1β expression via the NLRP3 inflammasome pathway activation. Our aim was to investigate NLRP3 inflammasome activation in endothelial cells (ECs) after Pg infection and Pg-LPS stimulation. In both situations, RT-PCR experiments demonstrated an increase of the NLRP3 mRNA level that can be potentiated by pre-treatment of ECs with 5 mM ATP. However, Western blotting analysis revealed that Pg infection induced a proteolysis of NLRP3 protein and a major decrease of the native protein. After ATP pre-treatment and/or Pg-LPS stimulation, this proteolysis was not observed, while NLRP3 protein levels were increased. Proteolysis of the NLRP3 protein was not observed with heat-killed Pg and inhibition of ECs protein synthesis with cycloheximide did not abolish the NLRP3 protein degradation induced by Pg infection in ATP pre-treated cells. Additionally, significant increases of secreted IL-1β were measured after ATP pre-treatment and/or Pg-LPS stimulation, but not after Pg infection. These data showed that Pg and Pg-LPS differentially controlled the NLRP3 inflammasome pathway in ECs, and suggested a novel potential mechanism developed by Pg to reduce IL-1β secretion and to escape host immune response.

Proteolysis

10.1177/1753425914523459

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Citations (38)

Impact of a periodontal course on oral hygiene and gingival health among senior dental students

Community Dentistry And Oral Epidemiology (1980)

Howard C. Tenenbaum

This survey attempted to determine the impact of the periodontal course on oral hygiene and gingival health among 50 senior dental students. The course included the following: patient motivation, instruction in oral hygiene procedures and plaque control, scaling and curettage, temporary splinting and occlusal adjustment. Without advance notice, plaque deposits were scored using the Plaque Index and gingival health was determined using the Gingival Index. The results were collected at the beginning and at the end of the periodontal course (about 2 months). The results were analyzed using the paired t-test. No improvement of either oral hygiene or gingival health was noted at the end of the periodontal course. It seems that even some dental students, who should know the direct relationship between bacterial plaque and periodontal diseases and should be better motivated than the average patient, failed to demonstrate effective oral hygiene. It is difficult to expert an improvement of patient oral hygiene, when the patients have been motivated by students who are unable to perform satisfactory personal oral hygiene themselves. It is suggested that a greater emphasis be placed on patient motivation and instruction in oral hygiene throughout the dental curriculum.

10.1111/j.1600-0528.1980.tb01303.x

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Citations (14)