Biomedical subjects
Publications and source records attributed to P D Greig.
We have modified the percutaneous skeletal muscle biopsy technique by applying suction to the biopsy needle. This has increased the reliability and the average size of the specimen but has allowed the procedure to continue to be safe and simple.
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The continent Koch ileostomy constitutes a major improvement in the quality of life for patients requiring an ileostomy. Complete continence is achieved in most patients, although the mechanisms underlying this control of fecal flow are poorly understood. Pressure studies on the pouch, the nipple valve and the outlet were preformed and results showed the presence of a high pressure zone in the nipple valve relative to the pouch. The high pressure zone maintained, even when the intra-abdominal pressure was raised or during contractions of the pouch, and most likely, contributes to continence. The pressure in the nipple valve and outlet was further intermittently increased by spontaneously occurring phasic and tonic contractions. Distention of the pouch with air caused a tonic contraction that was first recorded from the pouch and that traveled aborally along the intestinal layers of the intususcepted nipple valve and the outlet. By frequent emptying of the pouch, such contractions are avoided, and the risk of desusception of the nipple valve may be reduced.
The long-term renal and hemodynamic effects of the peritoneovenous shunt for intractable ascites were studied in 11 patients to elucidate the mechanism of its persistent beneficial effect. Sodium balance studies were performed in 7 patients. All had patent shunts and no clinically detectable ascites. On a 20-mEq sodium diet, the mean sodium excretion was 17.2 +/- 5.3 mEq/day which was increased over the preoperative mean of 2.4 +/- 0.4 (p < 0.025) on the same diet. There was a 100% increase in creatinine clearance over the preoperative level (p < 0.0005). The mean plasma renin activity and serum aldosterone levels were within normal limits in most patients, and the sodium excretion correlated inversely with the levels of each. During 100-mEq sodium challenge diet, the sodium excretion ranged from 4 to 130 mEq/day with a mean of 56.1 +/- 16.5 and with 6 of the 7 patients displaying sodium retention. On this diet the mean creatinine clearance was 104.3 +/- 6.4 ml/min, and the mean plasma renin activity and serum aldosterone levels had decreased physiologically with the higher sodium intake. Again the sodium excretion correlated inversely with the serum aldosterone on the 100-mEq sodium diet. In 8 patients, the portal pressure, as reflected by the wedge hepatic vein pressure, had decreased by a mean of 37% (p < 0.0005). But, despite this, 2 of the 8 patients had major variceal hemorrhages postoperatively. There was a significant inverse correlation between the increase in sodium excretion and the fall in portal pressure in 4 patients. Thus, sodium retention in cirrhosis is multifactorial with the reninaldosterone system and, possibly, portal hypertension per se both playing a role. Peritoneovenous shunting in carefully selected patients partially reverses the sodium retention and renders patients more manageable over the long term.
To investigate the acute effect of sustained volume expansion in patients with chronic hepatic ascites, renal and hemodynamic studies were performed on six patients receiving the peritoneovenous shunt. Within 1 hr of shunt insertion, the cardiac output rose by 20% to 60% above the preoperative level and the renal blood flow by 70% to 300%. At the same time both the plasma renin activity and serum aldosterone levels fell to a mean of 34% of the preoperative levels. The urine output increased from fourfold to 38-fold, but the sodium excretion increased in only two of the six patients. The data show that the acute effect of sustained volume expansion is predominantly on water rather than on sodium excretion. This manoeuver acutely suppressed circulating renin and aldosterone levels; however, the blunted natriuretic response suggests that other factors are involved in the sodium retention in these patients.
The results and complications in our first 23 consecutive patients receiving the peritoneovenous shunt for intractiable hepatic ascites are presented. A good initial diuretic effect was obtained in 20 of the 23 patients, with reversal of hepatorenal failure in 3 of 5 patients. The postoperative complication rate was high (74 percent). Infection, coagulopathy and complication of the underlying liver disease contributed to a mortality rate of 26 percent. Late complications were related to the primary liver disease. The 6 month survival rate was 58 percent and the 1 hear survival rate 52 percent with five patients followed up for more than 2 years. Because of the significant morbidity and mortality associated with the peritoneovenous shunt, we recommend it only for patients with massive intractable hepatic ascites whose condition is refractory to maximal medical therapy.
Variceal hemorrhage can be controlled by nonsurgical means in over 50% of patients. As a result, their general hepatic status can often be improved by preoperative preparation for the elective procedure. The major problem following elective end-to-side portacaval shunting is encephalopathy; it occurs in up to one half of patients who undergo this shunting procedure. Mesocaval shunting has been proposed as a better operation because of lower frequency of encephalopathy; however, the authors' experience has not confirmed this. Distal splenorenal shunting, as shown by the results of a prospective controlled trial, does have a lower frequency of encephalopathy, but the initial morbidity and mortality are higher and an improvement in the duration of survival is not yet evident.
Fifteen patients with chronic liver disease having a peritoneovenous shunt for chronic intractable ascites were studied prospectively for renal function and hemodynamic changes during balance studies, pre-, peri-, and postoperatively. Shunt insertion caused a rapid redistribution of ascites into the intravascular compartment with hemodilution and significant rises in cardiac output (9 patients) (P less than 0.025) renal blood flow (3 patients) (P less than 0.025), and creatinine clearance (15 patients) (P less than 0.005), and decreases in plasma renin activity (10 patients) and serum aldosterone levels (9 patients) (P less than 0.025). Despite these changes, small repeated doses of furosemide were required to start and maintain a diuresis and natriuresis with sodium excretion rising from 7.2 +/- 4.1 to 174 +/- 44 meq/day (P less than 0.0005) in the 15 patients. At 2 wk postoperatively, the 15 patients had lost a mean of 7.5 kg in weight associated with a persistent improvement in creatinine clearance and a continued natriuresis, 15.9 +/- 7 mEq/day (P less than 0.005), despite no statistically significant change in cardiac output (7 patients) or renal blood flow (4 patients) compared with preoperative levels. This operation is an effective therapy for refractive ascites, but the incidence of potentially fatal complications makes us hesitate to recommend it except for patients resistant to normal conservative measures.
To define the relationship between portal hypertension and renal excretion of salt and water, two acute animal models of portal hypertension were investigated. In both models, it was necessary for systemic and renal hemodynamics to remain unchanged during the creation of portal hypertension so as to eliminate the effects of change in these parameters on renal excretion. In eight dogs, portal hypertension was induced by controlled tightening of a ligature around the superior hepatic vein and changes in hemodynamics were prevented by controlled i.v. titration with canine plasma. Rises in portal pressure 9.3 +/- 2.6 to 15.6 +/- 2.3 cm H2O were associated with significant decreases in urine volume 1.57 +/- 0.53 to 0.66 +/- 0.21 ml per min (p less than 0.05) and urinary sodium excretion [340 +/- 82 to 145 +/- 75 mEq per min (p less than 0.05)]. In contrast, similar experiments in five dogs in which the portal vein was partially ligated with increases in portal pressure from 8.3 +/- 0.6 to 18.6 +/- 0.5 cm H2O resulted in no change in urinary volume or sodium excretion. Acute reversible portal hypertension induced by hepatic vein constriction is associated with acute reversible retention of water and salt in the absence of changes in renal blood flow and creatinine clearance which only occur when the liver is involved and not with portal vein constriction.
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)
The elevated catecholamine levels in cirrhotic patients with ascites have been proposed to be due to sympathetic overactivity secondary either to reduced intravascular volume or to an underlying cardiovascular abnormality such as reduced pressor responsiveness. Furthermore, these elevated catecholamine levels have been proposed to be involved in the pathogenesis of salt and water retention. Therefore, the effect of peritoneovenous shunting on the circulating levels and renal excretion of catecholamines were studied in six patients with massive refractive ascites preoperative within the first 8 hr postoperative and by 2 weeks postoperative under metabolic conditions. The recirculation of ascites into the intravascular compartment resulted perioperatively in significant rises in cardiac output (p = 0.001), para-amino-hippurate clearance (p = 0.08), creatinine clearance, diuresis (p = 0.05) and natriuresis (p = 0.06). Systemic blood pressure remained unchanged while systemic vascular resistance decreased (p less than 0.05). Preoperative circulating levels of free catecholamine were highly elevated, and renal vein concentrations were about 25% higher than renal arterial levels. Perioperatively, there was little change in circulating catecholamine levels or distribution of renal blood flow although renal artery and vein concentrations tended to equalize. In contrast by 2 weeks postoperatively, free catecholamine levels had fallen to within the normal ranges: mean norepinephrine from 1,477.6 +/- 194.6 to 395 +/- 62.9 pg per ml (p less than 0.05); epinephrine from 276 +/- 74.2 to 65.7 +/- 15.0 pg per ml (p less than 0.02), and dopamine from 325.6 +/- 175.2 to 47.9 +/- 5.3 pg per ml.(ABSTRACT TRUNCATED AT 250 WORDS)
The Sugiura operation has been reported to have low operative mortality, rebleeding, and encephalopathy rates when carried out in a predominantly nonalcoholic Japanese population with good liver function. A literature review of reports of the Sugiura procedure outside Japan reveals a high complication and mortality rate when it is used as an emergency procedure in patients with advanced liver disease, especially in those with alcoholic cirrhosis. Uncontrolled studies report results that differ little from the Japanese series when the operation is confined to good-risk patients in the elective situation. Our experience with the Sugiura operation supports its role in these circumstances, especially in patients with portal vein thrombosis and normal liver function. The only good prospective controlled trial has been carried out in patients with schistosomiasis and suggests that the Sugiura operation is far superior to total shunt and may have a slight advantage over the Warren shunt because of its low incidence of postoperative encephalopathy. More controlled trials are required to establish its role in good- to moderate-risk patients with alcoholic cirrhosis.
BACKGROUND: To define the imaging features of lymphoproliferative disorders that occur after liver transplantation. METHODS: A retrospective review of 605 liver transplantations between 1985 and 1998 showed 20 patients with posttransplantation lymphoproliferative disorders (PTLDs). All relevant clinical, imaging, and pathologic findings were reviewed. RESULTS: PTLDs occurred in 13 men and seven women (mean age = 43.3 years, age range = 18-68 years). The time to diagnosis of disease ranged from 1.5 to 51 months (mean = 14 months) posttransplantation. Cervical, thoracic, or abdominal lymphadenopathy was seen in 11 patients (55%). A complex portal mass in five patients (25%) was the second most common manifestation of PTLD, ranging in size from 5 to 12 cm. Other findings included gastrointestinal tract involvement in three patients (15%) seen as a duodenal mass and diffuse wall thickening in one patient and large bowel thickening in two patients with preexisting inflammatory bowel disease. CONCLUSION: There is a wide spectrum of findings in lymphoproliferative disorder after liver transplantation. The presence of lymphadenopathy, a portal mass, or bowel thickening indicates a need for further investigation to reach a pathologic diagnosis.
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