[Frontiers in Bioscience 3, b1-10, January 1, 1998]

	[Frontiers in Bioscience 3, b1-10, January 1, 1998] Reprints PubMed CAVEAT LECTOR
	ELECTROCHOLEDOCHOGRAM: A STUDY OF THE ELECTROMECHANICAL ACTIVITY OF THE COMMON BILE DUCT IN THE DOG Ahmed Shafik Department of Surgery and Experimental Research, Faculty of Medicine, Cairo University, Cairo, Egypt. Received 10/3/97 Accepted 11/3/97 3. MATERIAL AND METHODS 3.1 Materials The study comprised 11 mongrel dogs (7 male and 4 female) with a mean weight of 13.6 ± 3.2 SD kg 3.2 Methods The animals were fasting during the night. They were premedicated with subcutaneously injected acepromazine (0.15 mg/kg) and anesthetized with intravenous sodium pentobarbital (35 mg/kg) given as a bolus injection at 20-25 mg/hour to maintain adequate anesthesia with spontaneous respiration. All dogs were intubated to assist ventilation.(range 11-16). The animals were selected from a population with normal liver functions and a normal CBD on sonographic examination. The dogs were put into cages one week prior to the study to get accustomed to the facilities. They were treated in compliance with the "Guide for the Care and Use of Laboratory Animals" (17). The abdomen was opened through an upper midline incision, and the GB, CBD, and duodenum were exposed. The canine CBD has a free and an intramural portion (18). The free portion, approximately 5 cm long and 2.5 mm in diameter, courses through the lesser omentum. The intramural portion measuring 1.5-2.0 cm in length, extends obliquely through the duodenal wall and is surrounded by the sphincter of Oddi (SO). The electric activity of the CBD was recorded by means of monopolar silver-silver chloride electrodes of a diameter of 0.8 mm each and covered with an insulating vinyl sheath sparing its tip (Smith-Kline Beckman, Los Angeles, CA, USA). Two electrodes were sutured, 1.5 - 2 cm apart, to the serosa of the free portion of the CBD, using a 5/0 vicryl stitch for each electrode (figure. 1). A metal cannula containing a 2-pin socket to which the electrodes were attached, was sutured to the anterior abdominal wall. Figure 1: Diagram illustrating the site of the electrodes applied to the common bile duct. The pressure within the CBD was measured by means of a 2F catheter which was introduced into the CBD through a puncture in its wall approximately 1 cm below the distal electrode. The catheter was fixed to the CBD by a 5/0 vicryl stitch. It had multiple side ports and a closed distal end to which a metallic clip was applied for fluoroscopic control. The catheter was connected to a pneumohydraulic capillary infusion system (Arndorfer Medical Specialities Greendale, WI, USA). The pump delivered saline continually via the capillary tube at a rate of 0.6 ml/min. The transducer outputs were registered on a rectilinear recorder (RS 3400 Gould Inc, OH, USA). Occlusion of the recording orifice produced a rate of rising pressure greater than 250 cm H₂O/s. Finally, the abdominal wound was closed and the dogs were allowed to awaken from anesthesia. The animals were given a 2-week resting period for wound healing prior to the start of the recordings. Insulated wire leads were attached to the pins in the cannula and connected to a Brush Mark 200 rectilinear pen recorder. The electric activity including frequency, amplitude and velocity of conduction, was recorded from the 2 electrodes in each dog for periods of 30 minutes daily on 15 different days. 3.2.1 Balloon distention of the CBD The effect of balloon-produced distention of the CBD on its electromechanical activity was tested in 4/11 dogs. The CBD was exposed as aforementioned. A 4F catheter tipped with a latex balloon of 2 mm in diameter (London Rubber Industries Ltd., London, UK), was introduced into the CBD through a puncture located 0.5-1 cm below the electrodes and was fixed to the duct by a 4/0 vicryl suture. The abdomen was closed. After 15 days to allow for wound healing, the balloon was inflated with 1 ml of carbon dioxide (CO₂). The controlled CO₂ source was the Heyer-Schulte CO₂ cystometer (Heyer-Schulte Corp, Goleta, CA, USA) which has a self-contained CO₂ system using disposable CO₂ cartridges. The CO₂ balloon filling was increased in increments of 0.25 ml to a total of 2 ml while the EMG activity was recorded. 3.2.2. CBD myotomy The direction of propagation of the electric waves was examined by means of multiple CBD myotomies. Myotomy comprised division of the adventitia and muscle layer of the CBD down to, but not including the mucosa. This was performed with the aid of fine surgical instruments, bright light and a magnifying loupe. The CBD wall was so thin that caution was required to avoid injury to the mucosa. In 6 dogs, the CBD was exposed as aforementioned. An annular myotomy was performed proximally to electrode 1 in two dogs, between electrodes 1 and 2 in two dogs and distally to electrode 2 in two dogs (figure. 2). After a free period of two weeks to allow for abdominal wound healing, the electric activity was recorded in each dog for periods of 30 minutes daily for 10 days. Figure 2: Location of the common bile duct myotomies. 3.2.3. Statistical analysis The results were analysed statistically using the Student’s t test. Differences assumed significance at p <0.05, and values were given as mean ± standard deviation (SD).

[Frontiers in Bioscience 3, b1-10, January 1, 1998]
Reprints
PubMed
CAVEAT LECTOR

ELECTROCHOLEDOCHOGRAM: A STUDY OF THE ELECTROMECHANICAL ACTIVITY OF THE COMMON BILE DUCT IN THE DOG

Ahmed Shafik

Department of Surgery and Experimental Research, Faculty of Medicine, Cairo University, Cairo, Egypt.

Received 10/3/97 Accepted 11/3/97

3. MATERIAL AND METHODS

3.1 Materials

The study comprised 11 mongrel dogs (7 male and 4 female) with a mean weight of 13.6 ± 3.2 SD kg

3.2 Methods

The animals were fasting during the night. They were premedicated with subcutaneously injected acepromazine (0.15 mg/kg) and anesthetized with intravenous sodium pentobarbital (35 mg/kg) given as a bolus injection at 20-25 mg/hour to maintain adequate anesthesia with spontaneous respiration. All dogs were intubated to assist ventilation.(range 11-16). The animals were selected from a population with normal liver functions and a normal CBD on sonographic examination. The dogs were put into cages one week prior to the study to get accustomed to the facilities. They were treated in compliance with the "Guide for the Care and Use of Laboratory Animals" (17).

The abdomen was opened through an upper midline incision, and the GB, CBD, and duodenum were exposed. The canine CBD has a free and an intramural portion (18). The free portion, approximately 5 cm long and 2.5 mm in diameter, courses through the lesser omentum. The intramural portion measuring 1.5-2.0 cm in length, extends obliquely through the duodenal wall and is surrounded by the sphincter of Oddi (SO).

The electric activity of the CBD was recorded by means of monopolar silver-silver chloride electrodes of a diameter of 0.8 mm each and covered with an insulating vinyl sheath sparing its tip (Smith-Kline Beckman, Los Angeles, CA, USA). Two electrodes were sutured, 1.5 - 2 cm apart, to the serosa of the free portion of the CBD, using a 5/0 vicryl stitch for each electrode (figure. 1). A metal cannula containing a 2-pin socket to which the electrodes were attached, was sutured to the anterior abdominal wall.

Figure 1: Diagram illustrating the site of the electrodes applied to the common bile duct.

The pressure within the CBD was measured by means of a 2F catheter which was introduced into the CBD through a puncture in its wall approximately 1 cm below the distal electrode. The catheter was fixed to the CBD by a 5/0 vicryl stitch. It had multiple side ports and a closed distal end to which a metallic clip was applied for fluoroscopic control. The catheter was connected to a pneumohydraulic capillary infusion system (Arndorfer Medical Specialities Greendale, WI, USA). The pump delivered saline continually via the capillary tube at a rate of 0.6 ml/min. The transducer outputs were registered on a rectilinear recorder (RS 3400 Gould Inc, OH, USA). Occlusion of the recording orifice produced a rate of rising pressure greater than 250 cm H₂O/s. Finally, the abdominal wound was closed and the dogs were allowed to awaken from anesthesia. The animals were given a 2-week resting period for wound healing prior to the start of the recordings.

Insulated wire leads were attached to the pins in the cannula and connected to a Brush Mark 200 rectilinear pen recorder. The electric activity including frequency, amplitude and velocity of conduction, was recorded from the 2 electrodes in each dog for periods of 30 minutes daily on 15 different days.

3.2.1 Balloon distention of the CBD

The effect of balloon-produced distention of the CBD on its electromechanical activity was tested in 4/11 dogs. The CBD was exposed as aforementioned. A 4F catheter tipped with a latex balloon of 2 mm in diameter (London Rubber Industries Ltd., London, UK), was introduced into the CBD through a puncture located 0.5-1 cm below the electrodes and was fixed to the duct by a 4/0 vicryl suture. The abdomen was closed. After 15 days to allow for wound healing, the balloon was inflated with 1 ml of carbon dioxide (CO₂). The controlled CO₂ source was the Heyer-Schulte CO₂ cystometer (Heyer-Schulte Corp, Goleta, CA, USA) which has a self-contained CO₂ system using disposable CO₂ cartridges. The CO₂ balloon filling was increased in increments of 0.25 ml to a total of 2 ml while the EMG activity was recorded.

3.2.2. CBD myotomy

The direction of propagation of the electric waves was examined by means of multiple CBD myotomies. Myotomy comprised division of the adventitia and muscle layer of the CBD down to, but not including the mucosa. This was performed with the aid of fine surgical instruments, bright light and a magnifying loupe. The CBD wall was so thin that caution was required to avoid injury to the mucosa. In 6 dogs, the CBD was exposed as aforementioned. An annular myotomy was performed proximally to electrode 1 in two dogs, between electrodes 1 and 2 in two dogs and distally to electrode 2 in two dogs (figure. 2). After a free period of two weeks to allow for abdominal wound healing, the electric activity was recorded in each dog for periods of 30 minutes daily for 10 days.

Figure 2: Location of the common bile duct myotomies.

3.2.3. Statistical analysis

The results were analysed statistically using the Student’s t test. Differences assumed significance at p <0.05, and values were given as mean ± standard deviation (SD).