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Appendicitis is the most common pediatric surgical emergency. Ultrasound (US) receives the highest appropriate rating scale in children with right lower quadrant pain suspected to have appendicitis. The US exam of the appendix has improved since Puylaert pioneered the technique of graded compression in 1986. In this article, we review ultrasonography of the pediatric appendix as it pertains to the normal appendix, acute appendicitis and the different sonographic manifestations. We also briefly describe technical optimization of image acquisition, common pitfalls and differential diagnoses.

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Ewing sarcoma of bone is classically a permeative lesion in the diaphysis of long bones in children. While they occur primarily in children and adolescents, they can be seen in young adults in their 20s, but these are typically seen in flat bones. The permeative nature of the lesion can elicit new bone formation creating a partially sclerotic appearance, cortical expansion presenting as a "Codman triangle," or have an "onion-skin" type of aggressive periosteal reaction/periostitis. Ewing sarcoma is rarely seen without an associated soft-tissue mass and is even rarer to just have benign-appearing periostitis (e.g., thick, uniform, or wavy cortex). We present such a case of Ewing sarcoma in a young adult confined to just the medullary metadiaphysis without cortical erosion or soft-tissue mass. To the best of our knowledge, this is the first case to be reported in the radiology literature.

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Scurvy results from a deficiency of vitamin C and is rarely seen in the United States. We describe the MRI findings of a case of scurvy in an autistic child with food-avoidant behavior. Advanced imaging is rarely performed in clinically well-understood disease entities such as scurvy. Typical radiographic findings are well described leading to definitive diagnosis, although the findings can be missed or misinterpreted given the rarity of scurvy in daily practice. To our knowledge, MRI features of scurvy in children in the US have been described in only one case report. This case of scurvy in an autistic child with food-avoidant behavior emphasizes that classic nutritional deficiencies, despite their rarity, must be included in the differential diagnosis of at-risk populations.

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Cerebral phaeohyphomycosis is often a fatal disease that typically takes a hematogenous spread after inhalation or accidental skin inoculation of pathogens. We present a patient with a history of heavy marijuana smoking while being on chronic steroid therapy for treatment of neurosarcoidosis who was found to have multiple brain abscesses from Curvularia sp. This is a ubiquitous soil-dwelling dematiaceous fungus that is generally thought to affect solely plants, but there is increasing evidence in the literature of it affecting humans and animals. We review the radiographic findings of neurosarcoidosis and cerebral phaeohyphomycosis as well as the pathophysiology of dematiaceous fungi infections.

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Congenital anomalous bands at the proximal jejunum resulting in obstruction have been described sporadically in the literature and are otherwise rare. We present a case of an 8 year-old girl with a nine-month history of intermittent vomiting and no history of prior surgery. The imaging workup includes an abdominal ultrasound, a single contrast upper gastrointestinal series, and a dual contrast computed tomography of the abdomen and pelvis. Surgical intervention revealed the presence of dense bands at the proximal jejunum without evidence of malrotation. Our report reviews the embryology and radiologic findings of this entity using different imaging modalities.

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CONTEXT: an estimated 252,000 to 312,000 individuals have undiagnosed human immunodeficiency virus (HIV) infection in the United States. To date, little has been known about osteopathic physicians' attitudes and practices regarding routine HIV testing. OBJECTIVES: to understand osteopathic primary care physicians' attitudes and practices toward HIV testing and sexual history taking and to examine factors associated with osteopathic physicians' recommendations of HIV testing at the initial patient visit. METHODS: a cross-sectional survey of osteopathic physicians was conducted at the 106th Annual Convention of the Florida Osteopathic Medical Association in February 2009. Survey participants were asked 36 questions about osteopathic physician and patient sociodemographic factors and osteopathic physician attitudes and office practices regarding HIV testing and sexual history taking. RESULTS: a total of 233 osteopathic physicians completed the survey, but only 160 respondents (69%) met inclusion criteria of working in primary care and spending more than 50% of their time with patients. Almost two-thirds of participants were men, 80% were white, and the age range was 28 to 83 years. Twenty-two percent of participants recommended HIV testing at the initial patient visit, and 18% recommended annual HIV testing for all patients. Eighty-seven percent obtained a separate consent form for HIV testing, and 19% included HIV testing in general consent forms. About two-thirds of participants recommended annual HIV testing for homosexual men. Three factors were associated with recommending HIV testing at the initial patient visit: (1) recommending an annual HIV test for sexually active patients (odds ratio [OR], 12.82; 95% confidence interval [CI], 3.97-41.67); (2) having an agree/strongly agree attitude toward HIV testing (OR, 5.59; 95% CI, 1.63-19.23); and (3) obtaining a general consent form that included permission for HIV testing (OR, 3.25; 95% CI, 1.07-9.90). CONCLUSION: osteopathic physicians who practice primary care medicine can play a crucial role in reducing the number of individuals with undiagnosed HIV infection. More concerted efforts are needed to help osteopathic physicians incorporate HIV testing as part of routine care for all patients.

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Gout is a systemic, metabolic disease that typically affects the peripheral joints. We describe an unusual presentation of gout affecting the facet joints and costovertebral joints in the thoracic and lumbar spine. A 54-year old man presents to the emergency department with increasing swelling and pain at the left elbow for one week and difficulty ambulating. The imaging work-up included plain radiographs of the left elbow, left wrist, and chest with subsequent admission for possible septic arthritis. MRI of the elbow showed olecranon bursitis and an erosion of the lateral epicondyle. CT scan demonstrated lytic cloud-like lesions localized to the facet joints and costovertebral joints of the thoracic and lumbar spine as well as bilateral medullary nephrocalcinosis. Possible hyperparathyroidism manifestations (including Brown tumors and medullary nephrocalcinosis) were evaluated with plains films of the hands; x-rays instead showed classic gouty arthritis. Our report reviews the disease, epidemiology, classic radiologic findings, and treatment of gout.

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PAN, a yeast poly(A) nuclease, plays an important nuclear role in the posttranscriptional maturation of mRNA poly(A) tails. The activity of this enzyme is dependent on its Pan2p and Pan3p subunits, as well as the presence of poly(A)-binding protein (Pab1p). We have identified and characterized the associated network of factors controlling the maturation of mRNA poly(A) tails in yeast and defined its relevant protein-protein interactions. Pan3p, a positive regulator of PAN activity, interacts with Pab1p, thus providing substrate specificity for this nuclease. Pab1p also regulates poly(A) tail trimming by interacting with Pbp1p, a factor that appears to negatively regulate PAN. Pan3p and Pbp1p both interact with themselves and with the C terminus of Pab1p. However, the domains required for Pan3p and Pbp1p binding on Pab1p are distinct. Single amino acid changes that disrupt Pan3p interaction with Pab1p have been identified and define a binding pocket in helices 2 and 3 of Pab1p's carboxy terminus. The importance of these amino acids for Pab1p-Pan3p interaction, and poly(A) tail regulation, is underscored by experiments demonstrating that strains harboring substitutions in these residues accumulate mRNAs with long poly(A) tails in vivo.

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The multigene family encoding the five classes of replication-dependent histones has been identified from the human and mouse genome sequence. The large cluster of histone genes, HIST1, on human chromosome 6 (6p21-p22) contains 55 histone genes, and Hist1 on mouse chromosome 13 contains 51 histone genes. There are two smaller clusters on human chromosome 1: HIST2 (at 1q21), which contains six genes, and HIST3 (at 1q42), which contains three histone genes. Orthologous Hist2 and Hist3 clusters are present on mouse chromosomes 3 and 11, respectively. The organization of the human and mouse histone genes in the HIST1 cluster is essentially identical. All of the histone H1 genes are in HIST1, which is spread over about 2 Mb. There are two large gaps (>250 kb each) within this cluster where there are no histone genes, but many other genes. Each of the histone genes encodes an mRNA that ends in a stemloop followed by a purine-rich region that is complementary to the 5' end of U7 snRNA. In addition to the histone genes on these clusters, only two other genes containing the stem-loop sequence were identified, a histone H4 gene on human chromosome 12 (mouse chromosome 6) and the previously described H2a.X gene located on human chromosome 11. Each of the 14 histone H4 genes encodes the same protein, and there are only three histone H3 proteins encoded by the 12 histone H3 genes in each species. In contrast, both the mouse and human H2a and H2b proteins consist of at least 10 non-allelic variants, making the complexity of the histone protein complement significantly greater than previously thought.

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