Biomedical subjects

D Gali

Publications and source records attributed to D Gali.

3 recordsLinked to original sources

PubMed1987

Vascular reactivity in reversible experimental obstructive jaundice.

We studied the effect of jaundice on in vitro vascular reactivity to cumulative doses of norepinephrine (NE) by measuring the maximal response (Rmax) and the concentration of NE required to cause a 50% response (ED50) of isolated vascular smooth muscle. For this we prepared helically cut strips of thoracic aorta from bile duct ligated (BDL) rats at 1, 3, 6, 14, and 28 days postligation and compared them with those of nonoperated and sham-operated controls. From 1 to 6 days post-BDL, changes in liver blood chemistry and liver histology indicated cholestasis with necrosis. By 14 days, the tests for liver function and histology indicated a return to normal liver function and histology. In nonoperated controls, mean Rmax increased significantly from 883 +/- 67 mg of tension to 1220 +/- 68 mg of tension (P less than 0.0025) from 0 to 28 days, whereas ED50 remained unchanged. In sham-operated controls and BDL rats, an age-dependent increase in Rmax was also observed. However, in the sham groups, ED50 tended to decrease compared with nonoperated controls, indicating a surgically induced "sensitization" phenomenon of the vascular smooth muscle. In contrast, this was not seen in BDL rats since in these groups, the ED50 remained unchanged and significantly higher than in the sham groups, in both the jaundiced (1-6 days) and nonjaundiced (14-28 days) period. Furthermore, these changes occurred in the absence of any alteration in portal pressure. These changes may be important in understanding the mechanism of hypotension and shock in postoperative patients with obstructive jaundice even after the jaundice has been relieved.

Animals↗

PubMed1985

Reversible suppression of the vascular contractile response in rats with obstructive jaundice.

Both patients and experimental animals with obstructive jaundice manifest vascular instability, with animals showing a blunted vascular response to norepinephrine (NE). We sought an intrinsic abnormality of vascular smooth muscle by studying the contractile response of isolated, helically cut aortic strips and intact portal veins to cumulative doses of NE in rats with bile duct ligation (BDL) at different times compared with sham-operated (SO) rats as controls. At 3 days after surgery, the mean cumulative maximal contractile response (Rmax) of the aortic strip of BDL rats (94.3 +/- 9.0 mg/mg tissue) was significantly lower than that of SO controls (145.3 +/- 11.5 mg/mg tissue) (P less than 0.005), associated with a tendency toward decreased sensitivity (half-maximal dose [ED50]) (18.2 +/- 6.75 nmol/L vs. 6.7 +/- 0.6 nmol/L). By 6 days, there was no difference between the two groups. Similarly, by 3 days the mean Rmax for portal vein contraction in BDL rats (694 +/- 72 mg) was significantly lower than that for SO rats (1000 +/- 143 mg). In contrast, mean ED50 of the portal veins of BDL rats (327 +/- 65 nmol/L) was significantly less than that of SO rats (881 +/- 216 nmol/L), indicating greater sensitivity. At 1 and 6 days after surgery there was no significant difference between the two groups. These alterations in the vascular contractile response coincided with the maximum increases in serum bilirubin and liver enzyme levels. In conclusion, this study indicates that the circulatory abnormalities associated with obstructive jaundice are associated, at least in part, with suppression of the vascular contractile response caused by some abnormality of the vascular musculature.

Alanine Transaminase↗

PubMedDate not supplied

Systemic hypotension and decreased pressor response in dogs with chronic bile duct ligation.

Vascular instability as defined by systemic hypotension and unresponsiveness to endogenous or exogenous vasoactive substances is a feature of both patients and experimental animals with obstructive jaundice. In this study, we have attempted to dissect the possible mechanisms for these abnormalities using both in vivo and in vitro methods. In vivo cumulative pressor responses (Rmax) to intravenous and intraarterial infusions of norepinephrine and angiotensin II and to intravenous infusion of angiotensin I were studied pre- and postoperatively in chronic bile duct-ligated dogs and compared to sham-operated dogs. Preoperatively, the pressor responses to the cumulative infusion of six doses of vasoactive substances in the pre-sham operated and pre-chronic bile duct-ligated dogs were not significantly different. Postoperatively, in the sham-operated dogs, there was no significant change in systemic blood pressure at 1 and 3 weeks, and only in isolated instances were significantly different pressor responses found compared to the preoperative result. In chronic bile duct-ligated dogs, the mean systemic blood pressure fell significantly from 117.2 +/- 3.1 to 107.2 +/- 3.0 mm Hg (p less than 0.01) at 1 week and remained significantly lower at 3 weeks [109.7 +/- 2.6 mm Hg (p less than 0.05)]. The Rmax to intravenous, but not intraarterial norepinephrine, was significantly decreased. In contrast, the Rmax to both intravenous and intraarterial angiotensin II infusions were significantly depressed at both 1 and 3 weeks. Similarly, the response to intravenous angiotensin I was significantly depressed. Cardiac output rose moderately in two sham-operated dogs from an average of 3.1 to 3.5 liters per min by 3 weeks associated with a decrease of 14.8% in peripheral vascular resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin I↗