Collagenous Myofibroblastic Tumor of the Mandible: Case Report of a Unique Locally Aggressive Neoplasm Journal Head and Neck Pathology

We report a locally aggressive collagenous myofibroblastic neoplasm of the mandible in an 18-year-old male. Clinically, the lesion presented with rapid growth and irregular mandibular bone destruction. Grossly, the tumor was 10 cm in greatest dimension, light-tan, firm, and involving the posterior one-thirds of the body and inferior half of the left mandibular ramus. Histologically, the lesion was composed of a loose spindle cell proliferation interspersed with periodic dense bands of collagen. The spindle cells reacted positively to smooth muscle actin, calponin, and focally to desmin and were negative for S-100, pan-cytokeratin, CD99, CD34 and caldesmon, supporting myofibroblastic derivation. At our 4 year follow-up, the patient remained free of local recurrence and surgery related complications. The clinicopathologic findings and the differential diagnosis of this lesion is presented and discussed.

Spectroscopic and functional investigations of the AMPA subtype of ionotropic glutamate receptors

Ion channels play a crucial role in the functioning of different systems of the body because of their ability to bridge the cell membrane and allow ions to pass in and out of the cell. Ionotropic glutamate receptors are one class of these important proteins and have been shown to be critical in propagating synaptic transmission in the central nervous system and in other diverse functions throughout the body. Because of their wide-ranging effects, this family of receptors is an important target for structure-function investigations to understand their mechanism of action. ^ α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors are one subtype of glutamate receptors and have been shown to be the primary receptors involved in rapid excitatory signaling in the central nervous system. Agonist binding to the extracellular ligand binding domain of these receptors causes various conformational changes that culminate in formation of the ion channel. Previous structural investigations have provided important information about their mechanism of action, including uncovering a relationship between the degree of cleft closure in the binding domain and activation of the receptor. However, what question remains unanswered is how specific interactions between the agonist and the protein interplay with cleft closure to mediate receptor activation. ^ To investigate this question, I applied a multiscale approach to investigate the effects of agonist binding on various levels. Vibrational spectroscopy was utilized to investigate molecular-level interactions in the binding pocket, and fluorescence resonance energy transfer (FRET) was employed to measure cleft closure in the isolated ligand binding domain. The results of these studies in the isolated binding domain were then correlated to activation of the full receptor. These investigations showed a relationship between the strength of the interaction at the α-amine group of the agonist and extent of receptor activation, where a stronger interaction correlated to a larger activation, which was upheld even when the extent of cleft closure did not correlate to activation. These results show that this interaction at the α-amine group is critical in mediating the allosteric mechanism of activation and provide a bit more insight into how agonist binding is coupled to channel gating in AMPA receptors. ^

A simplified protocol for the treatment of acute radiation overexposures from sources external to the body

When compared to other types of occupational injuries, radiation overexposure events are somewhat rare, so health care providers may not be familiar with the actual clinical care to be provided when such an event occurs. Radiation overexposure treatment decisions are predicated on the amount of radiation dose received, which is a value many health care providers may not have the knowledge or expertise to either calculate or even estimate. Even the different units of measure for radiation exposure and dose received can be a source of confusion. The prompt treatment of radiation overexposure victims could be enhanced and facilitated through the creation of a single, simple protocol that consists of the various means of dose measurement and estimation, correlated to the corresponding appropriate clinical care measures. This culminating experience will assemble essential information currently maintained in disparate references to create a single, simplified protocol to facilitate the treatment of victims of acute external radiation overexposure. ^

Associations of perceived body image and subjective social status with levels of physical activity in Mexican American adolescents

The current study is a secondary data analysis of a prospective cohort study that examined demographic and psychosocial variables and their associations with physical activity levels in Mexican-American adolescents in Houston, Texas. Body image, subjective social status, and anxiety were the main variables of interest. The sample included 952 unrelated Mexican-American adolescents in Houston, Texas. The majority (84.2%) of the study population did not meet physical activity standards prescribed by the CDC.^ In a multivariate model controlling for age, socioeconomic status, gender, general body image, preferred body image, subjective social status, and anxiety, gender and subjective social status were found to be the strongest determinants of physical activity levels. Males and those with a high subjective social status were more likely to participate in physical activity than those with low subjective status. Lower levels of anxiety and a more positive body image were also found to be associated with higher levels of physical activity. In multivariate analyses gender and subjective social status showed the strongest associations with physical activity.^