Biomedical subjects

Jason A Cohen

Publications and source records attributed to Jason A Cohen.

4 recordsLinked to original sources

PubMed2006

Are all melanomas the same? Spitzoid melanoma is a distinct subtype of melanoma.

BACKGROUND: Although the majority of melanomas demonstrate high rates of mutations in B-RAF or N-RAS that result in constitutive activation of the mitogen-activated protein kinase-signaling pathway, emerging data suggest molecular differences among melanoma subtypes. In this study, the authors evaluated the contribution of B-RAF and N-RAS mutations to the pathogenesis of Spitzoid melanomas. METHODS: In total, 33 Spitzoid melanomas were analyzed for clinical and pathologic characteristics as well as for hot-spot mutations in the B-RAF and N-RAS genes. In the majority of patients (28 of 33 melanomas), the tumors were confined to the skin with no evidence of metastasis (average follow-up, 32.5 mos). There were five metastasizing melanomas (5 of 33 tumors) with regional or systemic spread. RESULTS: Of 33 Spitzoid melanomas, only 1 showed the V600E mutation in the B-RAF gene (1 of 33 tumors; 3%). It was noteworthy that none of the metastatic Spitzoid melanomas (0 of 5 tumors; 0%), of which 2 resulted in fatal outcomes, demonstrated mutations in B-RAF or N-RAS. CONCLUSIONS: In contrast to the majority of cutaneous melanomas, activating hot-spot mutations in B-RAF or N-RAS were not involved in the pathogenesis of Spitzoid melanoma. These data suggested that Spitzoid melanoma is a distinct form of melanoma with unknown genes and/or signaling pathways involved in its development.

Adolescent↗

PubMed2006

Contextual knowledge reduces demands on working memory during reading.

An experiment is reported in which young, middle-aged, and older adults read and recalled ambiguous texts either with or without the topic title that supplied contextual knowledge. Within each of the age groups, the participants were divided into those with high or low working memory (WM) spans, with available WM capacity further manipulated by the presence or absence of an auditory target detection task concurrent with the reading task. Differences in reading efficiency (reading time per proposition recalled) between low WM span and high WM span groups were greater among readers who had access to contextual knowledge relative to those who did not, suggesting that contextual knowledge reduces demands on WM capacity. This position was further supported by the finding that increased age and attentional demands, two factors associated with reduced WM capacity, exaggerated the benefits of contextual knowledge on reading efficiency. The relative strengths of additional potential predictors of reading efficiency (e.g., interest, effort, and memory beliefs), along with knowledge, WM span, and age, are reported. Findings showed that contextual knowledge was the strongest predictor of reading efficiency even after controlling for the effects of all of the other predictors.

Adolescent↗

PubMed2003

Strongyloides appendicitis: unusual etiology in two siblings with chronic abdominal pain.

Appendicitis is one of the most common causes of acute surgical disease in children and young adults. Parasites, however, are one of the uncommon etiologies. An 8-year-old girl and her 7-year-old sister presented with more than 2 months of chronic abdominal pain that became worse over a 1-week period before presentation. The 2 sisters presented 1 month apart. Both had similar symptomatology and physical examination findings. At operation, the surgical findings included an inflamed appendix with a cross section of the parasite Strongyloides. Strongyloides appendicitis has occurred almost exclusively in areas endemic to the parasite. Its environment is more common outside the United States but occasionally is seen in the Southeast region and in institutionalized individuals. The presentation of acute exacerbation of chronic abdominal pain coupled with the pathologic finding of Strongyloides in an acutely inflamed appendix, should alert the clinician of other possible cases. This increased index of suspicion will allow more prompt diagnosis and help avoid the morbidity of delayed operation.

Abdominal Pain↗

PubMed2003

Recurrent eosinophilic mastitis.

Systemic diseases rarely present with manifestations in the breast. Disorders such as sarcoidosis and pyoderma gangrenosum have been described to produce signs and symptoms in the breast. Peripheral eosinophilia is a systemic disease associated with a finite group of conditions including asthma, allergic or atopic disease, collagen vascular disease, and parasitic infection. In addition it has been described in association with several malignancies. A 50-year-old woman with a history of asthma and significant eosinophilia presented with an enlarging breast mass. Complete excision of the mass revealed eosinophilic mastitis. Two years later the patient again presented with a large mass in the same breast. Repeat excision demonstrated the same pathology. The clinical significance of this lesion is important because it presents as an enlarging, painless, dominant mass. Excision is necessary for management and to conclusively rule out malignancy. Its recurrence despite excision to negative margins, however, may indicate that control of the eosinophilia--and possibly the underlying disorder--is important to prevent further recurrence.

Breast↗