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Biomedical subjects

B Sigel

Publications and source records attributed to B Sigel.

At least 127 records · Page 7Linked to original sources
PubMed1968

Effect of blood flow reversal in liver autotransplants upon the site of hepatocyte regeneration.

We studied the role of the direction of intrahepatic blood flow upon the location of hepatocyte formation in regenerating liver. Single liver lobes in the dog were autotransplanted to the region of the neck with the blood supply reestablished in a manner to perfuse the hepatic lobule from portal tract to central vein or, in a reverse direction, from central vein to portal tract. Partial resection of the nontransplanted liver was later performed to induce regeneration in the grafts by humoral means. Tritiated thymidine was administered, and radioautographs were prepared from excised graft and nontransplanted liver. In the "straight" blood flow grafts, as well as in all nontransplanted livers, labeled hepatocytes indicating DNA synthesis were found predominantly in the vicinity of the portal tracts. In the "reverse" blood flow grafts, labeled hepatocytes were more prevalent about the central veins. Thus, the localization of hepatocyte formation in the lobule during active liver regeneration cannot be attributed to an inherently greater capacity of periportal liver cells to divide but is probably related to their preferential exposure to blood constituent changes (humoral mechanisms). Hepatocyte regeneration in the presence of abnormal directional circulation might lead to lobular disorganization resulting in consequent biochemical aberrations despite the formation of new cells.

Animals↗
PubMedDate not supplied

Ultrasonic detection of viscera slide as an indicator of abdominal wall adhesions.

Real-time ultrasonography can detect the movement of viscera immediately deep to the abdominal wall. This motion of abdominal contents is called viscera slide, and is produced by the force of respiratory motion (spontaneous viscera slide) or by manual ballottement of the abdomen (induced viscera slide). Viscera slide was observed in 18 "normal" subjects (no history of previous abdominal surgery or peritonitis) and in 24 subjects at "risk" for abdominal wall adhesions because of previous abdominal operations or past history of peritonitis. In 14 of the 24 "risk" group subjects, spontaneous and induced viscera slide was restricted to excursions of less than 1 cm (58.3%). Operations were performed on 18 patients, which confirmed the fact that restriction of ultrasonically detected viscera slide identified abdominal wall adhesions in all cases, but no adhesions were found in patients with normal viscera slide. This ultrasonic finding of restricted viscera slide may be useful in the preoperative discovery and localization of abdominal wall adhesions prior to laparoscopy or laparotomy.

Abdomen↗
PubMedDate not supplied

Technique of ultrasound examination during laparoscopic cholecystectomy.

Intracorporeal ultrasonography was used as a new method to examine the bile ducts during laparoscopic cholecystectomy. A prototype rigid 7.5-MHz ultrasound probe, 10 mm in diameter and 50 cm in length, was introduced during 25 laparoscopic cholecystectomies. A dual scanning technique was developed for complete examination of the bile duct. This entailed transverse scanning via the subxyphoid trocar and longitudinal scanning via the umbilical trocar. The intrahepatic ducts were also visualized by placing the probe on the liver surface. Color Doppler imaging was useful to quickly distinguish the duct from vascular structures. Laparoscopic ultrasonography clearly delineated the bile ducts in all operations except one. The time required for imaging was significantly shorter for ultrasonography than for cholangiography. Our preliminary experience demonstrates that a complete examination of the bile ducts can be performed with intracorporeal ultrasonography in a relatively short period of time.

Bile Ducts↗
PubMedDate not supplied

Operative ultrasonography during hepatobiliary and pancreatic surgery.

On the basis of our experience with operative ultrasonography during hepatobiliary and pancreatic surgery, its indications, benefits, and disadvantages are summarized. High-resolution operative ultrasound scanning of the liver, biliary tract, and pancreas was performed during 357, 735, and 242 operations, respectively. The benefits of operative ultrasonography were categorized as acquisition of diagnostic information otherwise not available, replacement for or complement to operative radiography, and guidance of surgical procedures. Operative ultrasonography provided beneficial information during 73 of 82 hepatic operations (89.0%), 57 of 69 noncalculous biliary operations (82.6%), and 177 of 242 pancreatic operations (73.1%). Operative ultrasonography was significantly superior (sensitivity 93.3%) to other screening tests for diagnosing liver metastasis from colorectal carcinoma evaluated in 189 patients, and it detected previously unrecognized metastatic tumors in 18 patients (9.5%). For screening common bile duct calculi during 666 operations, operative ultrasonography and operative cholangiography were comparable in all indices of accuracy except for a higher predictability of a positive test of operative ultrasonography (94.8% versus 71.7%). For diagnosing portal vein invasion of pancreatic carcinoma, operative ultrasonography provided better overall accuracy than preoperative studies (89.7% versus 64.1%). On the basis of operative ultrasound findings, previously planned surgical procedures were altered in 32 of 82 hepatic operations (39.0%) and 24 of 145 pancreatic operations for chronic pancreatitis (16.6%). Operative ultrasound guidance of various surgical procedures was performed during 88 hepatic and 84 pancreatic operations, including 40 ultrasound-guided hepatectomies and 42 pancreatotomies. Operative ultrasonography has a number of advantages, such as safety and speed in performance, wide application, high diagnostic accuracy, and ability of guiding procedures. Its disadvantages are the limitation of the fields of view in certain applications, the need for special equipment, and a slow learning curve.

Biliary Tract↗