In vivo electrochemical demonstration of potassium-evoked monoamine release from rat cerebellum

In vivo electrochemical methods were employed to study the potassium (K⁺-evoked release of monoamines from the cerebellum of the chloral hydrate anesthetized rat. K⁺-evoked releases were elicited using micropipette-Nafion-coated graphite epoxy electrode arrays in the granule/Purkenje cell layer, molecular layer, and white matter. These recorded releases were generally found to be reversible, moderately dose-dependent, and reproducible. However, the temporal dynamics of the releases were different for the cell layer versus molecular layer records. Releases were infrequently observed in cerebellar white matter, an area which is relatively devoid of monoamine containing terminals. The signals recorded from the cell and molecular layers were significantly attenuated by pretreatment with nomifensine, a potent catecholamine reuptake blocker, significantly prolonged the K⁺-evoked signals observed in both the granule/Purkenje cell and molecular layers. These data, taken together with earlier reports on the electrophysiological responses to activation of cerebellar noradrenergic inputs, support the conjecture that in vivo electrochemical recording methods have the sensitivity and spatial resolution for studies of functional monoamine release from brain regions that have a diffuse or laminated monoamine innervation.     

Einmal- versus wiederverwendbare Instrumente in der laparoskopischen Cholezystektomie — Kostenkalkulation und Nutzwertbestimmung

Zusammenfassung Grundlagen: Seit Einführung der laparoskopischen Cholezystektomie wird diskutiert, ob bei diesem Eingriff Einmal- oder wiederverwendbare Instrumente eingesetzt werden sollten. Argumenten der Wirtschaftlichkeit wurden Aspekte der Sicherheit und Hygiene entgegengestzt. Eine Beurteilung des Ger?teeinsatzes unter Berücksichtigung der Kosten als auch des Nutzwertes der Instrumente ist bis heute nicht erfolgt. Methodik: Es wurde ein Kostenvergleich von 3 Varianten des Instrumenteneinsatzes durchgeführt (1. wiederverwendbare Instrumente, 2. Einmalger?te, 3. kombinierte Anwendung). Der Wirtschaftlichkeitsrechnung wurde eine Nutzwertbestimmung der einzelnen Instrumente durch die Operateure entgegengestellt. Ergebnisse: Durch den Einsatz von wiederverwendbaren Instrumenten ist eine betr?chtlichen Kostenreduktion (5888 ATS bei ausschlie?licher Anwendung von wiederverwendbaren Ger?ten. 3945 ATS bei kombiniertem Einsatz) zu erreichen. Der Nutzenvergleich zeigte beim Clipsetzer und dem Port für die erste Insertion Vorteile für die Einmalinstrumente. Schlu?folgerungen: Aufgrund der Ergebnisse von Kostenkalkulation und Nutzwertbestimmung stellt der kombinierte Einsatz von wiederverwendbaren und Einmalinstrumenten derzeit die beste Alternative dar.      

Solitary bronchioloalveolar carcinoma: CT criteria

The computed tomographic (CT) scans of 30 patients with solitary bronchioloalveolar carcinoma were reviewed. Common features at CT included the peripheral or subpleural location of a pulmonary mass (25 cases), pseudocavitation (18 cases), heterogeneous attenuation (17 cases), irregular margins forming a star pattern (22 cases), and pleural tags (21 cases). Using these CT criteria, four independent observers attempted to identify cases of bronchioloalveolar carcinoma from a larger sample of lung cancers and benign lesions by categorizing a series of test cases into four probability categories. Although the bronchioloalveolar carcinomas were correctly ranked in the two highest probability categories 75% of the time (in 45 of 60 cases), there was considerable overlap with other lung lesions, particularly with adenocarcinoma and large cell undifferentiated carcinoma. However, even though the typical features of bronchioloalveolar carcinoma are not invariable or highly specific, they are characteristic enough to suggest the diagnosis.     

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.