Patricia A. Smith

Anomalies of the inferior vena cava and renal veins: embryologic and surgical considerations.

Anomalies of the inferior vena cava and renal veins occur infrequently but if unidentified can lead to significant morbidity during surgical exploration. An understanding of the embryologic development of the vena cava and its tributaries is necessary to understand the genesis of these sometimes complex anomalies and their accompanying anatomic variants. Newer radiologic modalities in the form of spiral computed tomography (CT) and three-dimensional reconstruction of spiral CT allow clear definition of the anatomy of these anomalies. Variations in the embryologic evolution of the vena cava dictate the different venous anomalies that may be encountered in the retroperitoneum. Additionally, the utility of newer radiologic modalities in the identification of these anomalies is discussed.

Dual-phase spiral CT angiography with volumetric 3D rendering for preoperative liver transplant evaluation: preliminary observations.

PURPOSE The goal of our study was to determine whether dual-phase spiral CT angiography with 3D volume rendering could be used for preoperative evaluation and patient selection for orthotopic liver transplantation candidates. METHOD Fifty consecutive potential candidates for liver transplantation were evaluated with dual-phase spiral CT with 3D volume rendering. Intravenous contrast medium was administered as bolus peripheral injection at 3 ml/s. The protocol consisted of a contrast-enhanced dual-phase spiral CT (arterial phase acquisition at 30 s after initiation of contrast medium injection followed by portal venous phase beginning at 60 s) with scan parameters of 0.75 s gantry rotation speed, 3 mm collimation, 5 to 6 mm/s table speed, and reconstruction at 1 mm intervals for arterial-phase images and 3 mm collimation for portal venous-phase studies (Siemens Plus 4 scanner; Siemens Medical Systems, Iselin, NJ, U.S.A.). All scan information was sent to a free-standing workstation (Silicon Graphics Onyx or Infinite Reality, Mountain View, CA, U.S.A.) for interactive real-time 3D volume rendering using a customized version of the Volren volume renderer (Silicon Graphics; Advanced Imaging Laboratory, Johns Hopkins Medical Institutions, Baltimore, MD, U.S.A.). The arterial phase was used to create vascular maps of the celiac axis including the origin(s) of the hepatic artery and origin of the superior mesenteric artery. The portal phase was used to define portal venous patency as well as the hepatic venous anatomy. All images were analyzed for vascular patency, shunting, or collateralization as well as the status of the underlying liver (i.e., liver size, cirrhosis, tumor, etc.). RESULTS All 50 studies were successfully completed without complication. The 3D CT angiograms defined key arterial and venous structures including origin(s) of the hepatic artery, portal vein and/or superior mesenteric vein thrombosis, cavernous transformation of the portal vein, and/or other collateral vasculature. Ten patients (20%) demonstrated anomalous anatomy at the origin(s) of the hepatic artery. Portal vein thrombosis with cavernous transformation of the portal vein was shown in six patients, and there were three cases of partial venous thrombosis. Underlying liver tumors as well as parenchymal liver disease were well defined. Hepatic masses were found in five patients. Masses were pathologically proven as hepatocellular carcinoma (n = 1), giant cavernous hemangioma (n = 1), hepatic adenoma (n = 1), and focal nodular hyperplasia (n = 2). CONCLUSION Preliminary results suggest that dual-phase spiral CT with CT angiography can provide a comprehensive preoperative liver transplant evaluation, supplying the necessary information for patient selection and surgical planning. As a single, minimally invasive examination, this should significantly impact patient care by minimizing procedures and avoiding potential complications.

Drosophila Transposable Elements: Mechanisms of Mutagenesis and Interactions With The Host Genome

Publisher Summary This chapter discusses the transposable elements of Drosophila . The chapter also discusses the mechanisms of mutagenesis and interactions with the host genome. Most spontaneous mutations in yeast and Drosophila are caused by the insertion of transposable elements. There are many examples of transposon-induced mutations in vertebrates and several recent reports have shown de novo insertions of transposable elements resulting in inheritable genetic defects or neoplastic transformation in humans. Therefore, the generation of mutant phenotypes by the insertion of transposable elements may be an evolutionarily general phenomenon that deserves study for both basic and practical considerations. In Drosophila, transposable elements may insert into genes and cause mutant phenotypes by a variety of mechanisms, the nature of which depends on the location of the insertion site with respect to the different structural and functional domains of the affected gene. Transposable elements may contain splice consensus sequences that when inserted into the transcription unit of a gene could result in aberrant processing patterns, or they may contain transcription termination signals that could cause premature termination of transcription of the mutant gene. Transposable elements also carry sequences necessary for transcription initiation—such as enhancers—that could alter the pattern of expression of adjacent genes.

Laparoscopic live donor nephrectomy: pre-operative assessment of technical difficulty1

Laparoscopic live donor nephrectomy decreases disincentives to live kidney donation. Thus, many centers are interested in adopting this procedure. However, the high stakes involved for both the donor and the recipient, and the technical difficulties of the operation, have tempered the enthusiasm of some surgeons. Ideally, if early in their series, surgeons could select patients that would be the least challenging technically, it would facilitate the dissemination of this operation. The purpose of this study is to determine if anatomic or radiologic parameters can accurately assess pre‐operatively the degree of technical difficulty of laparoscopic live donor nephrectomy for any individual patient. 
Abdominal spiral three‐dimensional CT scanning was performed prior to laparoscopic donor nephrectomy. CT scans were reviewed for six radiographic anatomic parameters. Seven clinical anatomic measurements relating to body habitus were recorded upon induction anesthesia at the time of surgery. Demographic data for gender, age, race, weight, height, and smoking history were collected. Following laparoscopic live donor nephrectomy, the following six component parts of the operation were graded on a scale of 1–4 (1=easy, 4=very difficult) for technical difficulty: a) mobilization of the colon; b) mobilization of the upper pole; c) dissection of the renal vein; d) dissection of the renal artery; e) division of the adrenal vein; and f) dissection of the ureter. Also, operative time, estimated blood loss, and intra‐operative fluid requirements were recorded as surrogate markers of operative difficulty. 
Forty‐one patients were included in the study. Laparoscopic donor nephrectomy was successfully completed in all cases. The sum of the difficulty scores was 9.9±3.1 (mean) (range, 6–18). No anatomic, demographic, or radiologic parameters were predictive of the total operative difficulty score. Of the surrogate markers, only operative time correlated with total difficulty score (R=0.47, p=0.003). Donor weight and abdominal girth correlated with operative time (R=0.50, p=0.002; R=0.38, p=0.019) but not with total difficulty score (R=0.10, p=0.51; R=−0.02, p=0.90, respectively). When the easiest cases and the hardest cases (≤25th percentile and ≥75th percentile total difficulty score, respectively) were segregated out, again no anatomic, demographic, or radiologic parameters were predictive of operative technical difficulty.

Three-dimensional CT angiography: Renal applications

CT angiography has become an effective noninvasive imaging modality for evaluating the renal vasculature. The current clinical applications for CT angiography and three-dimensional (3D) imaging related to the kidneys and renal vasculature include evaluation of renal artery stenosis, renal diseases related to aortic diseases, living-related renal donor candidates, and preoperative evaluation of renal masses for possible nephron sparing surgeries. Imaging parameters need to be individually prescribed for renal CT angiography depending on the diagnostic goal of the examination. Methods for optimizing spiral CT protocols including patient preparation, contrast administration, image acquisition parameters, and image reconstruction will be covered.

The suppressor of hairy-wing binding region is required for gypsy mutagenesis

SummaryWe undertook a deletional analysis of the gypsy retrotransposon in order to determine which sequences of the element are required for its mutagenic effect. We show that a phenotype indistinguishable from that ofy2 flies can be generated by transformingy− flies with a construct containing theyellow gene and a gypsy element located at the same insertion site inyellow as found iny2 flies. When flies are transformed with similar constructs in which increasing amounts of the 5′ transcribed untranslated region of gypsy have been removed, either a partialy2 revertant or a completely revertant phenotype is obtained. These results yield direct proof that the region of gypsy to which thesu(Hw) protein binds is required for the generation of mutant phenotypes by this retrotransposon.