Dental students' reflections on their community-based experiences: the use of critical incidents

Dental schools are challenged to develop new learning methodologies and experiences to better prepare future dental practitioners. The purpose of this study was to gain insight into the community-based experiences of dental students as documented in their critical incident essays and explore what learning outcomes and benefits students reported. Following two required community-based clinical rotations, each student wrote a reflection essay on a self-defined critical incident that occurred during the rotations. Rotations took place in settings such as a public health clinic, special needs facility, hospital, or correctional institution. Essays for two classes of students were content-analyzed for recurring themes and categories. Students were confronted in their rotations with a wide range of situations not typically encountered in dental academic settings. Their essays showed that, as a result of these rotations, students developed increased self-awareness, empathy, communications skills, and self-confidence. Critical incidents challenged assumptions and stereotypes, enhanced awareness of the complexities of dental care, and raised complex ethical dilemmas. The essays also illustrated a heightened sense of professional identity and enabled students to appreciate the role dentistry can play in impacting patients' lives. We concluded from the study that community-based dental education that includes a process for reflection holds promise as an educational strategy to facilitate the personal and professional development of future dentists.     

Reflective learning in community-based dental education

Learners gain additional value from community-based education when they are guided through a reflective process. The purpose of this article is to describe how structured reflection assignments and methods are incorporated in the University of North Carolina School of Dentistry's community-based DISC (Dentistry in Service to Communities) program. The following strategies are described as ways to enrich community-based learning experiences for dental students: photographic documentation; written narratives; critical incident reports; and mentored post-experiential small group discussions. Fieldwork and course-related examples are drawn from community-based dental experiences to illustrate how reflective teaching approaches can enhance student learning. A directed process of reflection is suggested as a way to increase the impact of the community learning experience.     

Direct and indirect cross-tolerance of alloreactive T cells by dendritic cells retained in the immature stage

BACKGROUND: Rejection of allografts entails the direct and indirect cross-recognition of donor major histocompatibility complex molecules by recipient alloreactive T cells. The ability to manipulate the state of dendritic cell (DC) maturation in vitro has enabled us to induce tolerance specifically targeting the alloreactive T-cell compartment. In this study, the immunoregulatory effect of alloantigen presentation by ex vivo-generated donor and recipient DCs retained in immature stage was investigated. METHODS: Dendritic cell were generated by culturing monocytes with granulocyte-macrophage colony-stimulating factor and interleukin-4. Ex vivo-generated tolerogenic DCs were characterized by flow cytometry and confocal microscopy. Recipient T-cell responses to donor or recipient DCs loaded with donor-derived apoptotic cells were assessed in a two-step culture system. RESULTS: Dendritic cells maintained their phagocytic and endocytic activities, and had significantly reduced capacity to prime recipient T cells. Moreover, primary coculture of recipient T cells with donor tolerogenic DCs rendered alloantigen-specific T cells hyporesponsive to a subsequent challenge with donor immunogenic DCs as evidenced by decreased proliferation and cytokine secretion. Importantly, recipient tolerogenic DCs loaded with donor-derived apoptotic cells were able to cross-tolerize recipient T cells. This was revealed by alloantigen-specific T-cell hyporesponsiveness on restimulation with the recipient immunogenic DCs loaded with different tissue-derived apoptotic cells obtained from the same donor.CONCLUSIONS: Dendritic cells retained in immature stage induce direct and most importantly indirect cross-tolerance of alloantigen-specific T cells. It may be likely that administration of donor and/or recipient DCs could be one means with which to promote tolerance induction in acute and chronic phases of organ transplant.     

Anti-epileptogenic effect of beta-carotene and vitamin A in pentylenetetrazole-kindling model of epilepsy in mice

Vitamin A (Vit A) and its derivatives have recently been reported to be implicated in synaptic plasticity. In this study, the possible effect of Vit A and its precursor, beta-carotene on acute seizure and kindling, induced by pentylenetetrazole (PTZ) was assessed. Vit A and beta-carotene were evaluated for their ability to: (1) elevate the threshold of clonic seizures induced by i.v. infusion of PTZ; (2) suppress the seizures (clonic and tonic) and lethality induced by i.p. PTZ in PTZ-kindled mice (anticonvulsant effect); (3) attenuate the development of sensitization to convulsive and lethal effects of i.p. PTZ in kindled mice (anti-epileptogenic effect). Diazepam was employed as positive control. All the drugs showed anti-epileptogenic effect against PTZ-induced tonic seizures and lethality. Vit A and beta-carotene had no effect on clonic seizures threshold and also on tonic seizures and lethality induced by PTZ in kindled mice. Non-genomic and genomic mechanisms could be involved in the anti-epileptogenic effect of Vit A and beta-carotene.     

Responsibility attitude in a sample of Iranian obsessive-compulsive patients

BACKGROUND: The study of distorted beliefs about responsibility attitude and interpretation has become the central theme in Salkovskis' (1985) and Rachman and Hodgson's (1980) models of Obsessive-Compulsive Disorder (OCD). AIMS: The aim of this research is to assess the responsibility attitude in Iranian OCD patients. METHODS: Twenty OCD patients were selected through available sampling from the case referred to psychology clinics. Two other patient groups comprised of 20 non-OCD anxiety disorder patients and 20 non-clinical participants were also chosen as comparison groups. All participants completed the Responsibility Attitude Scale (RAS) and Responsibility Interpretation Questionnaire (RIQ). RESULTS: Analyses revealed statistically significant differences between OCD group and comparison groups on both RAS and RIQ. In addition, both RAS and RIQ scores were associated with the severity of OCD assessed by the Yale-Brown scale. CONCLUSIONS: These findings suggest that responsibility attitude and interpretations are the prominent features of OCD in Iranian patients and are associated with the severity of illness.     

Pharmacoepidemiology I: a review of pharmacoepidemiologic study designs

This article is the first of two parts on pharmacoepidemiology, a relatively new science that explores drug efficacy or toxicity using large observational study designs. The number of pharmacoepidemiologic studies published in medical journals has increased, as these studies have explored drug-related questions that at times cannot be answered in randomized clinical trials. Four pharmacoepidemiologic study designs will be discussed that explore the association between a specific pharmacologic agent and a disease of interest: cohort studies, case-control studies, case-crossover studies, and case-time-control studies.     

Pharmacoepidemiology II: the nested case-control study--a novel approach in pharmacoepidemiologic research

This article on pharmacoepidemiology, the second of two parts, is a more focused discussion of the methodology of cohort studies and case-control studies, the basic methodologies of which were discussed in part I. The nested case-control study incorporates the strengths of both the cohort and case-control studies but may alleviate some of the methodologic challenges inherent in both types of studies. In a nested case-control study, a cohort of individuals is followed during certain time periods until a certain outcome is reached. The analysis is conducted as a case-control study in which cases are matched to only a sample of control subjects. Matching allows for control of potential confounding variables such as age, calendar time, and disease duration. Also, the time dependency of an exposure can be quantified without complicated statistical techniques. Matching the cases and controls by time allows the investigator to stratify exposure based on current, past, or intermittent use. By using the principles of epidemiology, the nested case-control study allows for the control of confounding variables, as well as better quantification of time-dependent exposures.     

The impact of a state children's health insurance program on access to dental care

BACKGROUND: Access to dental care for low-income children is limited. The authors examined the impact of a new state children's health insurance program, or SCHIP, in North Carolina on children's access to dental care. METHODS: Parents of 639 school-aged children responded to two surveys that asked about their child's access to dental services before enrollment and one year after enrollment in the new program. The authors used two-tailed McNemar tests to detect statistically significant changes within subjects. RESULTS: The percentage of school-aged children with a visit to a dentist in the previous year increased from 48 percent at baseline to 65 percent after one year in the program. Reported unmet dental need decreased from 43 percent at baseline to 18 percent after one year of enrollment. The proportion of children reported to have a usual source of dental care improved after enrollment in the program. CONCLUSION: The SCHIP model in North Carolina is an innovative program that has made a significant impact on access to dental care for school-aged children. PRACTICE IMPLICATIONS: SCHIP dental programs that resemble private insurance models and reimburse dentists at rates close to market rates hold the potential to address problems associated with dental access for low-income children.     

An update on the role of PET/CT and PET/MRI in ovarian cancer

This review article summarizes the role of PET/CT and PET/MRI in ovarian cancer. With regard to the diagnosis of ovarian cancer, the presence of FDG uptake within the ovary of a postmenopausal woman raises the concern for ovarian cancer. Multiple studies show that FDG PET/CT can detect lymph node and distant metastasis in ovarian cancer with high accuracy and may, therefore, alter the management to obtain better clinical outcomes. Although PET/CT staging is superior for N and M staging of ovarian cancer, its role is limited for T staging. Additionally, FDG PET/CT is of great benefit in evaluating treatment response and has prognostic value in patients with ovarian cancer. FDG PET/CT also has value to detect recurrent disease, particularly in patients with elevated serum CA-125 levels and negative or inconclusive conventional imaging test results. PET/MRI may beneficial for tumor staging because MRI has higher soft tissue contrast and no ionizing radiation exposure compared to CT. Some non-FDG PET radiotracers such as ¹⁸F-fluorothymidine (FLT) or ¹¹C-methionine (MET) have been studied in preclinical and clinical studies as well and may play a role in the evaluation of patients with ovarian cancer.     

Morphological and electrophysiological features of F76 and D1 neurones of the sub-oesophageal ganglia of Helix aspersa in vitro and in culture

Identified neurones F76 and D1 of the suboesophageal ganglia of Helix aspersa were studied in the isolated ganglia in vitro and in culture. The neurones were examined electrophysiologically with current clamp and morphologically either with intracellular injections of Lucifer Yellow or biocytin. These nerve cells had very similar resting membrane potentials and responses to injected current. The projections of D1 and F76 have been characterised, with both neurones having two main axons. The F76 neurones project to the left pallial, right pallial, anal, and visceral nerves as well as to the left and right pleural ganglia. The D1 neurones have similar projections except that they do not project to the anal and visceral nerves. The bilateral symmetry to the pallial nerves and pleural ganglia is discussed. These cells were also studied electrophysiologically after mechanical isolation and culture. F76 and D1 neurones were separated by dissection (no enzymes) and cultured in three ways. In normal snail Ringer they remained viable for up to two weeks with no development. In Ringer preincubated with a ganglia or containing endothelial growth factor, neurite outgrowths were seen. Membrane potentials were significantly lower in cultured neurones than in vitro and the after hyperpolarization never went below resting in cultured cells but it did in vitro.