A web-based simulation of a longitudinal clinic used in a 4-week ambulatory rotation: a cohort study

Background  

Residency training takes place primarily on inpatient wards. In the absence of a resident continuity clinic, internal medicine residents rely on block rotations to learn about continuity of care. Alternate methods to introduce continuity of care are needed.     

Imaging findings in pseudocystic osteosarcoma

OBJECTIVE: Our purpose was to describe four female patients with osteosarcoma whose clinical and imaging findings primarily suggested either simple or aneurysmal bone cyst. All lesions were osteolytic, intracompartmental, and expanded bone without periosteal reaction. None of the patients presented during the peak age incidence for osteosarcoma. From imaging to histologic diagnosis, the discovery of osteosarcoma ranged from 1 week to 3 years. CONCLUSION: Atypical osteosarcoma may rarely mimic simple or aneurysmal bone cyst radiologically and may show a nonmalignant rate of growth. It may be more frequently encountered in females and may not present during the peak age incidence for osteosarcoma. Microscopically, the tumors were not cystic, necrotic, or telangiectatic but were conventional osteosarcoma and osteoclast-rich osteosarcoma.     

Giant vertebral notochordal rest: a lesion distinct from chordoma: discussion of an evolving concept

A 14-year-old boy with severe back pain for several years is described. Roentgenograms, bone scans, and computed tomographic scans of the spine were normal, but magnetic resonance imaging studies showed a lumbar vertebral body lesion, confined to the bone, with low T1- and high T2-weighted signal intensities. Histologically, the lesion consisted of sheet-like notochordal-type tissue, containing physaliphorous cells but lacking the usual features of chordoma. A diagnosis of giant notochordal rest was made. A review of prior possible examples of this recently described and controversial entity is made with a discussion of its embryologic foundations and distinction from chordoma.     

Spondylometaphyseal dysplasia, corner fracture type: a heritable condition associated with coxa vara

The authors present the radiographic features of a previously incompletely delineated bone dysplasia, which they call spondylometaphyseal dysplasia, corner fracture type. This is a dominant heritable condition associated with short stature and developmental coxa vara. The progressive hip deformity usually causes significant disability requiring surgical correction. Developmental coxa vara, simulated corner fractures of long tubular bones, and vertebral body abnormalities result in a diagnostic constellation. Knowledge of these distinctive radiologic features allows accurate diagnosis, which in turn should lead to appropriate genetic counseling and possibly to earlier, more efficacious surgical treatment of the coxa vara.     

Posteroanterior wrist radiography: importance of arm positioning

Proper interpretation of wrist radiography requires a standardized radiographic technique. We obtained posteroanterior (PA) radiographs of the wrist in nine patients in three different arm positions to study the effect of arm position on ulnar styloid process orientation. An appearance simulating a normal anteroposterior (AP) wrist radiograph was present in six of nine PA radiographs when the arm was positioned next to the trunk, and the elbow was flexed to a 90% angle. The orientation of the ulnar styloid was not helpful in differentiating either pronated from supinated wrist positions or AP from PA projections. We concluded that radiographic screening of the carpus should be performed with standardized wrist positioning and nomenclature as described in modern radiographic technological texts. Supplemental projections should be exposed and interpreted with an understanding of the position of the arm and the direction of the incident radiographic beam at the time of examination.     

Subtalar arthrosis: evaluation with CT

The surgical implantation of a Silastic wedge into the lateral subtalar joint (subtalar arthrosis) is designed to restrict the osseous malalignment associated with a flexible or neurogenic flatfoot deformity. We used CT to examine patients who had persistent pain after a subtalar arthrosis and retrospectively reviewed our experience with CT scans of 13 subtalar implants (seven patients) during a 3.5-year period. The CT scans of four asymptomatic subtalar implants showed each implant in the expected position and orientation, and the findings were considered normal. Conversely, the findings on CT scans of all nine painful implants (seven patients) were interpreted as abnormal. The scans showed oblique orientation of four implants (44%), loosening of three implants (33%), extruded methyl methacrylate in the subtalar joint in two implants (22%), and abnormal calcaneal recession in two implants (22%). Five of the nine painful implants were revised with improvement or resolution of symptoms. Our experience suggests that CT scanning of the subtalar joint can show the position and orientation of a subtalar implant and identify causes of persistent pain after a subtalar arthrosis.     

A comparison of polymerase chain reaction and an infectivity assay for human immunodeficiency virus type 1 titration during virus inactivation of blood components

Three examples of human plasma-derived concentrates, intermediate- purity factors VIII and IX, and fibrinogen were spiked with tissue culture-grown human immunodeficiency virus type 1 (HIV-1) strain RF. All examples were freeze-dried and heated at 80 degrees C for 72 hours by using validated production process models. HIV-1 infectivity was measured by a syncytial infectivity assay in C8166 cells and then compared with levels determined by nested HIV polymerase chain reaction (PCR). The infectivity assay demonstrated a reduction index of at least 4.5 log10, while PCR showed an average 1.7 log10. Large amounts of HIV- 1 RNA (10(5)) were still detectable by PCR in samples in which infectivity assays failed to detect any HIV-1. These data suggest that HIV-1 PCR levels do not parallel HIV-1 infectivity levels during virus- inactivation procedures involved in coagulation factor concentrate production. PCR was able to detect the RNA associated with inactivated HIV-1 particles in the factor concentrates, which allows the conclusion that PCR is not a useful test with which to monitor virus-inactivation procedures such as heating at 80 degrees C for 72 hours. This judgment contrasts with the more definite and sensitive role of PCR in diagnosing HIV-1 infection in patients in whom a positive HIV-1 PCR result correlates with active HIV-1 infection and with PCR's usefulness in monitoring virus removal.