The renal vasodilator properties of six endogenous substances were tested before and 4 hr after ligation of the common bile duct. Two substances, acetylcholine and a glucocorticoid, retained their vasodilator properties at a fixed dose following acute biliary obstruction. Dopamine was still able to increase glomerular filtration rate and renal blood flow, but demonstrated an attenuated response. Several other agents, glucagon, glycine, and bradykinin, lost their renal vasodilator actions at the dosages employed. For these latter three compounds, control studies using sham-obstructed dogs and identical waiting periods demonstrated no loss of vasoactive effect. When the order of experimental protocol was reversed, i.e., acute biliary obstruction followed by a 4-hr period without obstruction, the same phenomenon was observed. When dogs were tested 5 days following biliary obstruction, glycine, glucagon, dopamine, and dexamethasone all failed to raise either GFR or renal perfusion. The infusion of bile or dialyzed bile, but not bile salts or bilirubin, also caused the failure of glucagon, glycine, and bradykinin to exert a renal vasoactive effect. Dogs with 4 hr of biliary obstruction appeared to react normally to the pressor effects of noradrenaline and angiotensin II and to the diuretic effects of iv furosemide. The obstruction of the bile ducts with percolation of bile constituents into the circulation appears to alter the sensitivity of the renal vasculature to certain endogenous vasoactive agents.

Acetylcholine↗

PubMed1984

Effects of bile and bile salt infusions on renal function in dogs.

A previous study in dogs indicated that 4 h of acute biliary obstruction was associated with an increment in the glomerular filtration rate (GFR), renal perfusion, and urinary sodium excretion. These effects could also be transmitted to a "recipient" dog following 2 h of cross circulation. In this study we examined the possible role of bile and bile products in reproducing these effects. The i.v. infusion of 15 mL of undiluted gallbladder bile produced a marked diuresis and natriuresis, while arterial pressure and GFR declined. Bile diluted as much as 1/100 in isotonic saline could produce an effect when infused intravenously. When bile diluted to 1/250 was infused into th left renal artery at 0.5 mL/min, a diuretic and natriuretic response was obtained. GFR and renal blood flow declined with more concentrated solutions, though blood pressure remained normal. Dialysis of bile, or prior incubation with cholestyramine or plasma, failed to uncover a renal vasodilator effect. Following the first two procedures, the diuretic properties of infused bile were lost. The infusion of small amounts of synthetic bile salts (taurocholate or glycocholate) into the left renal artery caused marked increments in urinary sodium excretion without any change in renal hemodynamics. The infusion of bilirubin was without effect on renal function. Taurine and glycine, the amino acids present in the conjugated bile acids, were injected i.v. Both caused marked diuresis and natriuresis, but only glycine increased GFR and renal perfusion. The plasma levels of these substances, however, were unchanged following 4 h of acute biliary obstruction. We conclude that while bile salts probably cause the diuresis of biliary obstruction, the mechanism for the increase in GFR has not yet been identified.

Animals↗

PubMed1983

Renal response to four hours of biliary obstruction in the dog.

Clearance studies were performed in anesthetized dogs before and 4 h after the acute obstruction of the common bile duct (ABDL). ABDL was not associated with any change in systemic hemodynamics or plasma volume. Glomerular filtration rate (GFR) rose by 15.3%, PAH clearance by 13.3%, and renal blood flow by 13% (all values significant at P less than 0.05). Fractional excretion rates of water and sodium rose from 0.29 to 1.1 and from 0.21 to 0.76%, respectively (P less than 0.05). These changes in renal function were associated with a failure of bile excretion rather than distension of the biliary tree or failure of bile to enter the duodenum. They did not depend on intact hepatic nerves, alteration of hepatic perfusion, or the release of gastrointestinal vasoactive peptides. The increment in renal perfusion was maintained for 2-3 days before returning to baseline levels. Several lines of evidence suggested that factors influencing the renal tubule and the renal microcirculation might be separate in nature: e.g., urinary sodium excretion (UNaV) could increase without a change in GFR; if ABDL was relieved, delta UNaV and delta GFR returned to base line with different time courses; and controlling perfusion to the left kidney during ABDL reduced but did not abolish the increase in UNaV. Both effects could be transferred to recipient dogs by cross-perfusion. We have demonstrated, therefore, that 4 h of ABDL may significantly influence renal function through the appearance of humoral factors in the circulation.

Acute Disease↗

PubMedDate not supplied

Energy and protein intakes of acute stroke patients.

BACKGROUND: Although protein-energy malnutrition has been cited as a frequent complication following stroke, there is very little data describing nutritional intake among hospitalized patients. OBJECTIVE: To report: i) the level of protein and energy intake, ii) the adequacy of intake during the first 21 days of hospitalization and iii) to examine the differences in nutritional intake associated with diet type (regular texture, texture-modified and enteral feeding). DESIGN: Prospective observational study of an inception cohort. The energy and protein intakes of well-nourished patients with recent onset of first time stroke were assessed at admission to hospital and at days 7, 11, 14 and 21. Adequacy of energy intake at each of these intervals was expressed as a percentage (actual intake/energy requirement assessed by indirect calorimetry x 100). Adequacy of protein intake was assessed in a similar manner, with 1 g/kg of actual or adjusted body weight used to estimate requirement. The nutritional intakes of patients receiving regular diets, dysphagia diets and enteral tube feedings were compared using one-way ANOVA. RESULTS: The average energy intakes of the entire study group ranged from 19.4-22.3 Kcals/kg/day over five observation points, representing 80.3-90.9% of measured requirements; protein intake and ranged from 0.81-0.90 g/kg day yielding adequacy of intake of 81-90% of requirement. There were significant differences in energy intakes and/or adequacy of intake of patients receiving different diet types at days 11, 14 and 21 (p < 0.05) and differences in protein intake and/or adequacy of protein intake at all intervals except admission (p < 0.05). Patients receiving enteral tube feedings consumed more calories and protein compared to those patients on regular or dysphagia diets. CONCLUSIONS: On average, newly diagnosed, well-nourished, hospitalized patients consumed 80-91% of their both their energy and protein requirements, in the early post stroke period.

Aged↗