Demodex: a skin resident in man and his best friend

Demodex mites are microscopic arachnids found in the normal skin of many mammals. In humans, it is well established that Demodex mite density is higher in patients with the skin condition rosacea, and treatment with acaricidal agents is effective in resolving symptoms. However, pathophysiology of rosacea is complex and multifactorial. In dogs, demodicosis is a significant veterinary issue, particularly the generalized form of the disease which can be fatal if untreated. In each species, clinical and molecular studies have shown that the host’s immunological interactions with Demodex mites are an important, but not fully understood, aspect of how Demodex can live in the skin either as a harmless commensal organism or as a pathogenic agent. This review outlines the role of Demodex mites in humans and dogs, considering morphology, prevalence, symptoms, diagnosis, histology treatment and pathogenesis.     

Attending Physicians' Perspectives of Resident Academic Half Day

Phenomenon: Academic health centers face significant challenges trying to improve medical education while meeting patient care needs. In response to problems with traditional forms of didactic education, many residency programs have transitioned to Academic Half Day (AHD), a curricular model in which learning is condensed into half-day blocks. In this model, trainees have protected educational time free from clinical responsibilities. However, an understanding of the impact on attending physicians and patient care when residents depart clinical sites for learning activities has not been well described. We sought to explore attending physicians’ perspectives when residents depart clinical sites to attend AHD. Approach: We performed a qualitative study with a grounded theory approach using individual semistructured interviews (December 2016–April 2017) of attending physicians who worked at inpatient and emergency department clinical sites from which residents departed to attend AHD. We used the constant comparative method, generating codes using an iterative approach and continuing sampling until saturation was reached. Major themes were identified and disagreements were resolved by consensus. Findings: Fifteen attending physicians from 6 clinical services were interviewed. Data analysis yielded 5 themes: emotional strain of workload, technology and systems challenges, patient safety and care concerns, disrupted resident learning, and the challenge to optimize resident education. Attending physicians, already working on busy services, felt frustrated and perceived having an increased workload when residents departed for AHD. They were concerned about safely entering orders in the electronic health record, impeded patient workflow, and further disruption of resident schedules already disrupted by duty hour restrictions and continuity clinic. Attending physicians described the importance of experiential learning from caring for patients and from structured didactic learning; however, the optimal balance was uncertain. Insights: We found that attending physicians experienced significant emotional strain, faced technological challenges, and were concerned about impeded workflow and patient safety when residents departed clinical sites for AHD. This is likely to be true whenever residents are pulled out of the clinical setting for any reason. Educators need to partner with hospital administrators to provide appropriate support for attending physicians when residents leave clinical sites, evaluate the effectiveness of different educational models, and determine how structured learning activities fit into the overall curriculum.     

Priming sentence comprehension in aphasia: effects of lexically independent and specific structural priming

Background & Aims: Impaired message-structure mapping results in deficits in both sentence production and comprehension in aphasia. Structural priming has been shown to facilitate syntactic production for persons with aphasia (PWA). However, it remains unknown if structural priming is also effective in sentence comprehension. We examined if PWA show preserved and lasting structural priming effects during interpretation of syntactically ambiguous sentences and if the priming effects occur independently of or in conjunction with lexical (verb) information.

Methods & Procedures: Eighteen PWA and 20 healthy older adults (HOA) completed a written sentence-picture matching task involving the interpretation of prepositional phrases (PP; the chef is poking the solider with an umbrella) that were ambiguous between high (verb modifier) and low attachment (object noun modifier). Only one interpretation was possible for prime sentences, while both interpretations were possible for target sentences. In Experiment 1, the target was presented immediately after the prime (0-lag). In Experiment 2, two filler items intervened between the prime and the target (2-lag). Within each experiment, the verb was repeated for half of the prime-target pairs, while different verbs were used for the other half. Participants’ off-line picture matching choices and response times were measured.

Results: After reading a prime sentence with a particular interpretation, HOA and PWA tended to interpret an ambiguous PP in a target sentence in the same way and with faster response times. Importantly, both groups continued to show this priming effect over a lag (Experiment 2), although the effect was not as reliable in response times. However, neither group showed lexical (verb-specific) boost on priming, deviating from robust lexical boost seen in the young adults of prior studies.

Conclusions: PWA demonstrate abstract (lexically-independent) structural priming in the absence of a lexically-specific boost. Abstract priming is preserved in aphasia, effectively facilitating not only immediate but also longer-lasting structure-message mapping during sentence comprehension.     

2‐deoxy D‐glucose treatment does not elicit a hair growth response in alopecia areata

2‐deoxy D‐glucose (2DG) was tested for efficacy in treating alopecia areata using the C3H/HeJ skin graft model. 2DG has proven to be efficacious in treatment of various mouse models of autoimmunity with minimal serious side effects noted. This agent has been shown to normalize abnormally activated T‐cell populations while also preventing cell surface expression of NKG2D; key factors defining alopecia areata disease progression. Daily oral ingestion of 2DG via drinking water to mice with patchy or diffuse alopecia areata for 16 weeks failed to prevent expansion of alopecia or cause regrowth of hair in treated mice. Histologically, there were no differences between treated and control groups. These results indicate that, while 2DG is effective for some autoimmune diseases, it was not efficacious for the cell‐mediated autoimmune mouse disease, alopecia areata.     

Diffuse dermal angiomatosis: a contributory factor to ulceration in a patient with renal transplant

We present the case of a 54‐year‐old patient with renal transplant who developed unusual vascular changes on the forearm distal to a functioning arteriovenous fistula, as well as a painful ulcerated lesion on her anterior abdominal wall. We believe that the diffuse dermal angioendotheliomatosis variant of reactive angioendotheliomatosis had a role in the pathogenesis of this patient's lesions.     

Variables associated with subjective cognitive change among Iraq and Afghanistan war Veterans with blast-related mild traumatic brain injury

Introduction: This study investigated variables associated with subjective decline in executive function among Veterans of Operations Enduring Freedom, Iraqi Freedom, and New Dawn (OEF/OIF/OND) following a history of blast-related mild traumatic brain injury (mTBI).

Method: Fifty-six male U.S. Veterans (M_Age = 35.3 ± 8.8 years) with a history of blast-related mTBI (6.6 ± 3.2 years post injury) completed a battery of self-report questionnaires and neuropsychological measures. Participants rated current and retrospectively estimated pre-mTBI executive function difficulties on the Frontal Systems Behavior Scale (FrSBe). A difference score (post- minus pre-mTBI ratings) was the dependent variable (?FrSBe). Linear regression models examined variables predicting ?FrSBe, including: pre-injury characteristics (education, premorbid intelligence), injury-related characteristics (number of blast exposures, losses of consciousness), post-injury clinical symptoms (PTSD Checklist–Military version; Pittsburgh Sleep Quality Index), and post-injury neuropsychological performances on executive function measures (Trail Making Test Part B; Controlled Oral Word Association Test; Auditory Consonant Trigrams; Wisconsin Card Sorting Test).

Results: While 11% of participants had a clinically elevated pre-injury FrSBe total score, 82% had a clinically elevated post-injury FrSBe total score. Only self-reported PTSD symptom severity independently predicted perceived change in executive function.

Conclusions: Many OEF/OIF/OND Veterans with a history of blast-related mTBI experience subjective decline in executive function following injury. Perceived executive function decline was associated with higher PTSD symptom severity, aligning with previous research associating PTSD with cognitive complaints. Results did not support a correspondence between perceived cognitive change and neuropsychological performances.