Physician assistants in academic radiology: the harborview experience

We describe a model of how physician assistants can be used in an academic medical center to expand radiologist productivity, and to enhance the departmental academic and educational missions. At Harborview Medical Center, following a training program and graduated responsibility under supervision, physician assistants provide initial interpretation of radiology studies, consultation to referring physicians, and perform less complicated interventional procedures. Acceptance of physician assistants by the radiologists, radiology residents, and referring physicians has been high. Although the impact of physician assistants on departmental clinical productivity is difficult to measure, our data suggest that radiologists are more efficient when physician assistants are assigned to service, both in terms of numbers of studies interpreted, and timeliness of reporting and billing. As a result of the success of our program, we believe that physician assistants can have an important role in radiology practice.     

Impact of Increasing Margin Around the Lumpectomy Cavity to Define the Planning Target Volume for 3D Conformal External Beam Accelerated Partial Breast Irradiation

The purpose of this study was to evaluate the dose to normal tissues as a function of increasing margins around the lumpectomy cavity in accelerated partial breast irradiation (APBI) using 3D-conformal radiotherapy (3DCRT). Eight patients with Stage 0-I breast cancer underwent treatment planning for 3DCRT APBI. The clinical target volume (CTV) was defined as a 15-mm expansion around the cavity limited by the chest wall and skin. Three planning target volumes (PTV1, PTV2, PTV3) were generated for each patient using a 0, 5-, and 10-mm expansion around the CTV, for a total margin of 15, 20, and 25 mm. Three treatment plans were generated for every patient using the 3 PTVs, and dose-volume analysis was performed for each plan. For each 5-mm increase in margin, the mean PTV:total breast volume ratio increased 10% and the relative increase in the mean ipsilateral breast dose was 15%. The mean volume of ipsilateral breast tissue receiving 75%, 50%, and 25% of the prescribed dose increased 6% to 7% for every 5 mm increase in PTV margin. Compared to lesions located in the upper outer quadrant, plans for medially located tumors revealed higher mean ipsilateral breast doses and 20% to 22% more ipsilateral breast tissue encompassed by the 25% IDL. The use of 3DCRT for APBI delivers higher doses to normal breast tissue as the PTV increases around the lumpectomy cavity. Efforts should be made to minimize the overall PTV when this technique is used. Ongoing studies will be necessary to determine the clinical relevance of these findings.     

Distinct phases in recovery of reconstituted innate cellular-mediated immunity after murine syngeneic bone marrow transplantation.

Defects in immune reconstitution after hematopoietic stem cell transplantation confer extreme infection risk on to the transplant recipient. Perturbations in adaptive immune reconstitution have been well characterized, yet defects in reconstituted innate cellular-mediated immunity remain largely unstudied. Recovery in innate effector cells was defined by using an established murine model of autologous bone marrow transplantation. Cytokine induction after cell culture and systemic stimulation with pathogen-associated molecular patterns was also measured for control, transplant-recipient, and irradiated-only animals. Early reconstitution (7 to 14 days) of donor-derived macrophages, dendritic cells, and polymorphonuclear cells was associated with recovery in interleukin (IL)-12p70 and IL-6 production. Later reconstitution (21 days) of natural killer cells was associated with interferon (IFN)-gamma recovery. Hence, splenocyte innate cellular-mediated immunity recovered to normal levels in cellularity and IL-12p70, IFN-gamma, and IFN-alpha production by 21 days after transplantation. In contrast, levels of systemic cytokine production from transplant-recipient and irradiated-only animals were preserved despite incomplete or absent hematopoietic reconstitution. These results suggest that innate immune responses to systemic inflammatory challenges are largely intact after autologous bone marrow transplantation, whereas local innate cellular-mediated immunity within reconstituting lymphoid organs may be impaired. The disparate effects of autologous hematopoietic stem cell transplantation on host immune function may translate to differences in susceptibility to local versus systemic infectious challenges.     

Coronary artery disease in the geriatric population

The elderly represent an increasingly important and challenging subset of the population of patients with ischemic heart disease. They are more likely to have comorbid conditions, atypical presentations, and unfavorable outcomes than their younger counterparts. Some of these findings are undoubtedly related to the structural and functional changes in the cardiovascular system associated with aging. The available data suggest that standard pharmacologic, thrombolytic, and definitive revascularization techniques have important roles in the therapy of geriatric patients but have been underused.     

The emergence of GABA-accumulating neurons during retinal histogenesis in the embryonic chick

The emergence of GABA-accumulating neurons was studied from stages 29 to 40 during retinal histogenesis in the chick, covering embryonic (E) days E6-E14, using autoradiographic analysis following incubation of isolated retinas with [3H]GABA (2 microM). Analysis was restricted to central retina which is more advanced in its differentiation than the periphery. On E6 numerous mitotic figures were present along the scleral border of the unstratified neuroepithelium. Specific localization of [3H]GABA was associated initially with somata situated in middle regions of the retinal expanse. Occasionally contiguous pairs of labeled cells were seen. The inner plexiform layer makes its appearance during E7; at that time silver grains were present over cell bodies located in the ganglion cell layer and the proximal portion of the inner nuclear layer, those of probable amacrine cells. As retinal stratification continued, more cells were observed to have elaborated membrane systems for GABA uptake with varying degrees of affinity. By E8, although dividing, non-labeled cells were in close proximity, GABA-labeled cells were observed in positions of horizontal cells. By E14, the pattern of label distribution appeared essentially similar to that reported for adult retina, i.e. [3H]GABA labeling was observed over horizontal cells and their processes, subpopulations of amacrine cells which appear to ramify extensively across the inner plexiform layer, selected perikarya of the ganglion cell layer, and the nerve fiber layer. In addition, a subpopulation of labeled photoreceptors, some identified as cones by virtue of oil droplets, was observed. Thus, preferential accumulation of GABA appears during E6, prior to formation of either inner or outer plexiform layers. The localization of [3H]GABA demonstrates that ganglion and amacrine cell bodies are labeled initially, followed by horizontal cells. Specific accumulation of [3H]muscimol, a potent agonist of GABA receptors, appears about E12 over cells located in proximal regions of the inner nuclear layer; these somata later ramify in sublaminae 2 and 4 of the inner plexiform layer.     

Single,mediastinal, unilobar lung -a rare form of subtotal pulmonary agenesis

We describe a case of a full-term infant with severe respiratory failure and pulmonary insufficiency caused by an anomaly consisting of a single, unilobar lung arising from the trachea and situated in the middle mediastinum. Plain film, echocardiogram, and surgical aspects will be described and correlated with the post mortem findings and embryologic considerations. We were unable to find a similar case reported in the literature and conclude that this rare lesion represent an intermediate form between total and unilateral pulmonary agenesis. Presented at the Society for Pediatric Radiology, Washington D.C. 12 April 1986     

Pilot study to enhance HIV care using needle exchange-based health services for out-of-treatment injecting drug users

The introduction of highly active antiretroviral therapy (HAART) has resulted in marked reductions in mortality and acquired immunodeficiency syndrome (AIDS) incidence across all risk groups; however, the proportionate decrease among injecting drug users (IDUs) has been less impressive. Much of the disparity in benefit to IDUs has been a consequence of decreased access to and receipt of potent antiretroviral combinations. Strategies to increase access to and utilization of HAART have included entry into drug treatment and abstinence. Unfortunately, as few as 15%–20% of active drug users in the United States, and in many other countries, are in drug treatment at any one time. We report a pilot project among out-of-drug treatment IDUs infected with human immunodeficiency virus (HIV); HIV therapy was successfully provided to active heroin injectors using the Community Health Care Van (CHCV) at sites of needle exchange. Subjects were willing to initiate, but were not receiving, recommended HIV therapy and were not interested in formal drug treatment. Antiretroviral therapy regimens were selected and linked to heroin injection timing. Weekly visits were scheduled by CHCV staff to assess adverse side effects and encourage adherence. Of the 13 participants, the mean baseline HIV-1 RNA level and CD4 lymphocyte count were 162,369 (log 5.21) copies per milliliter and 265 cells per milliliter, respectively. By 6 months, the proportion whose HIV-1 RNA was below the limits of detection (<400 copies/mL) was 85% (N=11); 77% (N=10) had nondetectable levels by 9 months. By 12 months, 54% (N=7) had a persistently nondetectable viral load, and the net increase in CD4 lymphocyte count was 150 cells per milliliter. As an additional and unintended benefit of this pilot project, 9 (69%) subjects chose to enter drug treatment after achieving a nondetectable viral load. Entry into drug treatment was associated with durability of viral suppression. This small pilot study suggests that health services based on needle exchange may enhance access to HAART among out-of-treatment HIV-infected IDUs. In addition, it demonstrates that this population can benefit from this therapy with the support of a nontraditional, community-based health intervention.     

Duodenal atresia and stenosis: Reassessment of treatment and outcome based on antenatal diagnosis,pathologic variance,and long-term follow-up

Duodenal atresia and stenosis was observed in 103 infants and children from 1972 to 1991. There were 59 girls and 44 boys. Atresia was noted in 79 instances and stenosis in 24. Maternal hydramnios was detected in 33 cases, 46 babies were premature, and 31 had Down's syndrome. Fifty-four infants had significant associated anomalies including 35 with cardiac defects. Diagnosis was achieved by prenatal ultrasound examination in 14 cases, observation of a double-bubble sign on abdominal radiograph in 73, and contrast studies in 30 infants including 24 with stenosis. At operation annular pancreas was noted in 37 cases, malrotation in 37 cases, anterior portal vein in 4, and a second web in 3. Surgical treatment included duodenoduodenostomy in 85, duodenotomy and web excision in 8, and duodenojejunostomy in 10. Operative survival was 95%. Deaths were related to complex cardiac defects. Despite antenatal diagnosis, prompt intervention, and apparent early surgical success (95% survival), late deaths (5%) and late complications including motility disorders, megaduodenum, gastroesophageal reflux, duodenal-gastric reflux, gastritis, peptic ulcer disease, blind loop syndrome, and biliary-pancreatic conditions may be observed months to years after management during the neonatal period. Modifications in surgical technique including early tapering duodenoplasty may be useful, and close long-term follow-up is an essential component of patient care.

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Resumen Se encontró atresia duodenal y estenosis en 103 niños, 59 de sexo femenino y 44 de sexo masculino, en el período 1972–91: atresia en 79 casos y estenosis en 24. Se registró hidramnios materna en 33 casos; 46 niños fueron prematuros y 31 presentaban síndrome de Down; 54 exhibían anomalías de significación, incluyendo 35 con defectos cardiacos. El diagnóstico fue establecido por ultrasonido prenatal en 14 casos, mediante la observación de burbuja doble en la radiografía abdominal en 73 y por estudio con medio de contraste en 30, entre los cuales había 24 con estenosis. En la operación se encontró páncreas anular en 37 casos, malrotación en 37, vena porta anterior en 4 y segunda membrana en 3. El tratamiento quirúrgico incluyó duodenostomía en 85 pacientes, duodenotomía y resección de membrana en 8 y duodenoyeyunostomía en 10. La tasa de sobrevida operatoria fue de 95%. Las muertes estuvieron asociadas con los defectos cardfacos complejos. A pesar de su diagnóstico prenatal, una intervención quirúrgica precoz y un aparente éxito operatorio (sobrevida de 95%), se observan muertes tardías (5%) y complicaciones a largo plazo tales como desórdenes de la motilidad intestinal, megaduodeno, reflujo gastroesofágico, reflujo duodeno-gástrico, gastritis, enfermedad ulcerosa péptica, síndrome de asa ciega y alteraciones biliopancreáticas, meses a años después del tratamiento y manejo neonatales. Algunas modificaciones en la técnica quirúrgica, tales como duodenoplastia, pueden ser de utilidad; el seguimiento cuidadoso a largo plazo constituye un componente esencial de la atención de estos pacientes.

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Résumé Entre 1972 et 1991, on a observé 79 cas d'atrésie duodénale et 24 cas de sténose duodénale chez un total de 103 enfants, 59 filles et 44 garçons. Une hydramnios a été retrouvée chez 33 des mères, 46 enfants étaient des prématurés et 31 avait un syndrome de Down. Chez 54 enfants, il y avait des malformations associées, dont 35 cardiaques. Le diagnostic avait été établi dans 14 cas par une échographie anténatale, par l'existence du signe de la double bulle sur les abdomens sans préparation chez 73 patients et par une étude du transit intestinal en double contraste chez 34 enfants, dont 24 avec une sténose. A l'opération, on a retrouvé un pancréas annulaire chez 37 enfants, une malrotation chez 37, une veine porte antérieure chez 4, et une membrane intraluminale chez 3. Le traitement a été une anastomose duodénoduodénale chez 85 enfants, une excision de membrane après duodénotomie chez 8 et une duodénojéjunostomie chez 10. La mortalité opératoire était de 5%, en rapport essentiellement avec des malformations cardiaques complexes. En dépit d'un diagnostic anténatal, une intervention précoce et un succès chirurgical apparent, la morbidité tardive est toujours possible et comprend essentiellement des anomalies de la motilité duodénale, le mégaduodénum, un reflux gastroesophagien, un reflux duodénogastrique, une gastrite, la maladie ulcéreuse, un syndrome de l'anse borgne, et d'autres anomalies biliopancréatiques qui peuvent se voir des mois ou des années après la période néonatale. Les modifications de la technique chirurgicale et notamment la duodénoplastie précoce ainsi qu'une meilleure surveillance à distance, peuvent en améliorer le pronostic.