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OBJECTIVE The electric activity of the liver was studied in 14 mongrel dogs, aiming at characterizing a normal electrohepatogram (EHG) that might act as a standard for abnormal recordings in hepatic pathological conditions. METHODS Three monopolar silver-silver chloride electrodes were sutured to the anterior liver surface under anaesthesia. A recording session of 60 min was performed daily for 10 days. The effect of temporary clamping of the hepatic artery and portal vein, and of liver insult by irradiation, on the hepatic electric activity was also studied. RESULTS Electric waves were recorded from the three electrodes. They were monophasic with a positive deflection, had identical frequency and amplitude from the three electrodes, and were reproducible when the test was repeated in the same animal. The mean frequency was 10.6 +/- 1.8 cycles/s and amplitude 63.7 +/- 11.4 microV. Fast activity spikes and abnormal waves were not encountered. Temporary occlusion of the hepatic artery and portal vein produced irregularities in the wave frequency and amplitude; the wave dysrhythmia disappeared after clamp release. The EHG following liver insult by irradiation exhibited two patterns: silent and dysrhythmic. CONCLUSION A normal EHG could be characterized in the canine model. A dysrhythmic pattern was produced when liver vessels were clamped and following liver injury. It is suggested that in liver diseases, the normal EHG pattern is deranged and might thus act as a diagnostic tool in such conditions.

Summary Somatosensory evoked potentials (SSEP) have been used during cerebral aneurysm surgery to monitor the integrity of neural pathways. The purpose of this study was to evaluate the effectiveness of SSEP monitoring as a predictor of neurological outcome during temporary arterial occlusion. In a series of 157 patients monitored, 97 patients had temporary occlusion of the feeding artery. Twenty-three patients developed a SSEP change during temporary occlusion, 15 reversible (recovery of the change after the release of occlusion), and 8 persistent (no recovery) changes. A persistent change predicted a postoperative neurological deficit in each case, whereas, of the 15 patients with reversible changes, only 5 had postoperative deficits. Seventyfour patients had no change on SSEP monitoring but 10 patients did have new neurological deficits postoperatively. The false positive rate was 43% and the false negative rate was 14%. SSEP was a better predictor of neurological deficits in patients with aneurysms of the carotid circulation than of the vertebral-basilar arteries. Despite these limitations, we find SSEP monitoring useful during temporary occlusion in cerebral aneurysm surgery.

Dacryocystorhinostomy with Jones tube placement has proven to be an effective method for correcting upper-system lacrimal drainage obstruction. The present case report illustrates the potential risk of bacterial contamination of the operative field during subsequent cataract surgery by retrograde passage of airway secretions. Temporary occlusion of the Jones tube by a silicone plug can eliminate this potential source of endophthalmitis. In addition, temporary occlusion of the Jones tube in the office can be used to determine the effectiveness of lacrimal drainage through a reconstructed canalicular system.

Experimental catheter obstruction of the left gastric (coronary) vein was explored in 10 dogs. Using a transjugular approach, the liver was punctured and the portal vein catheterized. Coaxially introduced catheters were then used to catheterize selectively and produce an intravascular obstruction (tamponade) of the gastric coronary vein. Ballon catheters were used for a temporary occlusion. Injection of a tissue adhesive, isobutyl 2-cyanoacrylate, was used for a definitive obliteration. The achieved results show the anatomical feasibility of this approach and give good perspective for development of a clinical method for percutaneous intravascular tamponade of the bleeding gastroesophageal varices in cirrhotics.

Spinal cord ischemia was produced in rabbits by temporary occlusion of the abdominal aorta just distal to the renal arteries; and recovery, or failure to recover, was assessed by examining the rabbits for permanent loss of sensory and motor function in the hind limbs. A temperature reduction of 3 degrees C during the period of circulatory impairment caused a doubling of the duration of ischemia that could be reversibly sustained. Intravenous administration of 5 mmoles/kg of MgCl2 before the ischemia (a dose sufficient to produce neuromuscular blockade) caused a 50% increase in the tolerable duration. The combination of the 3 degrees C reduction in temperature and the elevated Mg++ increased by about 3 fold the duration of ischemia that could be sustained before irreversible damage occurred. These results may have implications for the care of patients subjected to marginal degrees of CNS ischemia.

To elicit evidence concerning neurogenic control, regional cerebral blood flow determined by measurement of cortical temperature was examined in monkeys. Following three hours of temporary occlusion of the MCA, pressure autoregulation was preserved in all control animals. Presumptive partial chemical sympathectomy, produced by the administration of either L-alphamethyl-tyrosine or 3-alpha-dimethyl-tyrosine methyl ester HCl, was associated with loss of pressure autoregulation following 1.5 hours of occlusion of the MCA on only the side of the occlusion. Failure of pressure autoregulation in the treated animals implies that sympathetic control was a partial requirement of proper postischemic pressure autoregulation.

Chronic obstructive pancreatitis-like histological and biochemical alterations were provoked in male Wistar rats with Ethibloc occlusion of the common bile duct and the main pancreatic ducts. After the disappearance of the glue from the ducts, a gradual and almost total recovery was demonstrated during a 2-month observation period. About 12 g/kg of alcohol (20% vol/vol) given daily by gastric intubation and ad libitum intake inhibited the recovery of pancreatic weight and enzyme contents in the occluded rats, and within a 2-month period chronic calcifying-type pancreatitis became evident with some signs of remaining obstructive pancreatitis-like lesions. Cessation of alcohol administration after 2 months resulted in a recovery of pancreatic weight and enzyme contents, although morphological regeneration was less pronounced and calcification remained visible in some rats. A 50% raw soy flour diet provoked some further changes in the proportion of enzymes without any supplementary increases of pancreatic weight and protein content. This animal model of chronic pancreatitis demonstrates that chronic obstructive and calcifying pancreatitis can appear together and earlier if the etiological factors act in combination. Suppression of pancreatic regeneration by alcohol seems to be necessary to maintain chronic pancreatitis-like lesions and to develop calcification.

Five patients underwent cerebral revascularization operations during which Biemer clips were used to occlude temporarily a branch of the middle cerebral artery. Postoperative angiograms revealed stenoses at the sites where the clips were applied. Excessive clip closing forces may have caused significant endothelial injury, which then produced the stenoses. Clips that exert a minimal occlusive force would avoid this response and are recommended for temporary occlusion of cortical arteries.