Nitroglycerin improves the hemodynamic response to vasopressin in portal hypertension

This study was designed to investigate whether the addition of nitroglycerin to vasopressin infusion could avoid the deleterious systemic effects of vasopressin while maintaining or enhancing the therapeutic benefits of portal pressure reduction. The effect of nitroglycerin on splanchnic and systemic hemodynamics was studied in cirrhotic patients and portal hypertensive dogs receiving i.v. vasopressin. During i.v vasopressin infusion (0.4 units per min), the cardiac output decreased in patients by 14% from 7.6 +/- 0.9 (mean +/- S.E.) to 6.5 +/- 0.7 liters per min, p less than 0.01, the mean arterial pressure increased 21% from 87 +/- 2 to 105 +/- 4, p less than 0.01, and the heart rate decreased 11% from 79 +/- 3 to 71 +/- 3, p less than 0.01. The administration of sublingual nitroglycerin (0.4 mg) returned all the systemic hemodynamic parameters to baseline values. In dogs, vasopressin infusion significantly reduced portal pressure and flow while increasing portal venous resistance. Nitroglycerin when added to the vasopressin infusion reduced portal venous resistance and further decreased portal pressure in dogs. In patients, vasopressin reduced the hepatic blood flow (44%), wedged hepatic venous pressure (11%), and the gradient between wedged and free hepatic venous pressures (23%). Nitroglycerin administration caused a further reduction of the wedged hepatic venous pressure (23.6 +/- 2.3 to 21.1 +/- 2.0, 11%, p less than 0.01). There was a small but not significant further decline (7%) in the hepatic venous pressure gradient. These results provide evidence that the addition of nitroglycerin to an i.v. infusion of vasopressin reversed the detrimental effects of vasopressin while preserving the beneficial effects.

Phylogeny and ontogeny of the phosphoglycerate mutases - III. Inactivation of rabbit muscle phosphoglycerate mutase (type M isozyme) by the sulfhydryl group reagents

1. The three phosphoglycerate mutase isozymes from mammals (types M, B and MB isozymes) differ in their sensitivity to the - SH group reagents. 2. Rabbit muscle phosphoglycerate mutase (type M isozyme) is reversibly inactivated by tetrathionate, rho-chloromercuribenzoate and Hg2+. 3. Titration with rho-chloromercuribenzoate shows the existence of two sulfhydryl groups per enzyme subunit, the modification of which produces a progressive decline in enzyme activity. 4. The apparent Km values for substrate and cofactor are not affected by tetrathionate treatment. 5. Phosphoglycerate mutase inactivated by tetrathionate and by rho-chloromercuribenzoate is unable to form the functionally active phosphorylenzyme when mixed with glycerate-2,3-P2, and is not protected by the cofactor against heating. 6. Glycerate-2,3-P2 protects against tetrathionate treatment, but fails to protect against Hg2+ and rho-chloromercuribenzoate inactivation.

Phylogeny and ontogeny of the phosphoglycerate mutases--IV. Distribution of glycerate-2,3-P2 dependent and independent phosphoglycerate mutases in algae, fungi, plants and animals

1. The distribution of the glycerate-2,3-P2 dependent and independent phosphoglycerate mutases (PGM) has been studied in more than eighty species. 2. PGM activity in the extracts has been measured in the presence and in the absence of glycerate-2,3-P2, at pH 7.5 and at pH 8.5. 3. All samples with glycerate-2,3-P2 dependent PGM possess higher activity at pH 7.5 than at pH 8.5. In contrast, samples with glycerate-2,3-P2 independent PGM possess lower activity at pH 7.5 than at pH 8.5. 4. In algae and fungi both glycerate-2,3-P2 dependent and independent PGM have been found. 5. In plants only glycerate-2,3-P2 independent PGM has been detected. 6. In animals both types of PGM are present. Independent PGM activity is present in sponges, coelenterates, myriapods, arachnids and echinoderms. Glycerate-2,3-P2 dependent PGM is present in platyhelminths, mollusks, annelids, crustaceans, insects and vertebrates.

Metabolism of glycerate-2,3-P2--II. Enzymes involved in the glycerate-2,3-P2 metabolism in chicken skeletal muscle

1. Four enzyme fractions which may be involved in the synthesis and breakdown of glycerate-2,3-P2 have been isolated from extracted skeletal muscle by gel-filtration and ion-exchange chromatography. 2. One of the fractions, corresponding to the glycerate-2,3-P2 dependent phosphoglycerate mutase, has been purified to homogeneity. In addition to the main enzymatic activity, it shows intrinsic glycerate-2,3-P2 synthase activity and glycerate-2,3-P2 phosphatase activity stimulable by glycolate-2-P. Its synthase activity represents about 10% of the total synthase activity of the tissue, and its phosphatase activity corresponds to about 60% of the total phosphatase activity. 3. Two of the fractions have glycerate-2,3-P2 synthase, glycerate-2,3-P2 phosphatase and phosphoglycerate mutase activities in a ratio similar to that of the glycerate-2,3-P2 synthase described in mammalian skeletal muscle. Their synthase activity corresponds to about 90% of the total synthase activity, and their phosphatase activity represents about 1% of the total phosphatase activity of the tissue. 4. The fourth fraction shows only glycerate-2,3-P2 phosphatase activity and represents about 40% of the total activity of the tissue. 5. It is suggested that in chicken skeletal muscle the metabolism of the glycerate-2,3-P2 is regulated in a way similar to that described in mammalian skeletal muscle.

Intracellular and exchangeable potassium in cirrhosis. Evidence against the occurrence of potassium depletion in cirrhosis with ascites

The intracellular potassium content of leukocytes, the extracellular fluid volume (82Br space), and exchangeable potassium were determined in 28 patients with cirrhosis of the liver (18 with ascites) and in 15 hospitalized controls. No intracellular potassium depletion could be identified in these patients. Leukocyte potassium was similar in cirrhotic patients with and without ascites (355.9 +/- 25.3 and 348.1 +/- 31.9 mEq/kg of dry solids, respectively) and in hospitalized controls (359.7 +/- 27.4) (mean +/- SD). The extracellular fluid volume was similar in controls and cirrhotics without ascites, but markedly increased in cirrhotics with ascites. The exchangeable potassium (mEq/kg of body weight) was similar in nonascitic cirrhotics and in hospitalized controls, but significantly lower in patients with cirrhosis and ascites. However, when the estimated weight of the extracellular fluid volume was substrated from the total body weight, thus obviating the influence of the increased extracellular fluid volume of ascitic patients in the body weight, the exchangeable potassium (mEq/kg of "corrected" body weight) was similar in cirrhosis with ascites (52.9 +/- 6.7 mEq/kg), nonascitic cirrhotics (55.8 +/- 6.1 mEq/kg) and hospitalized controls (55.0 +/- 8.3 mEq/kg), and a significant correlation was obtained between the exchangeable potassium and the leukocyte potassium content. In five patients, the measurements were repeated after relieving ascites with diuretics. No change was observed in the leukocyte potassium, but exchangeable potassium (mEq/kg of body weight) increased, reaching values not significantly different from controls or nonascitic cirrhotics. The exchangeable potassium (mEq/kg of "correct" body weight) did not change. Our results strongly suggest that potassium depletion was not present in the series of cirrhotic patients studied.

Effect of angiotensin-II blockade on systemic and hepatic haemodynamics and on the renin-angiotensin-aldosterone system in cirrhosis with ascites

We have studied the effect of angiotensin-II blockade with saralasin on the cardiovascular and hepatic hemodynamics and on the renin-angiotensin-aldosterone system in fourteen patients with cirrhosis and ascites. Control measurements showed that most of the patients had a low mean arterial pressure, high plasma volume, normal or high cardiac index, low peripheral resistance and high plasma renin activity and aldosterone concentration. The wedged hepatic venous pressure was increased in each patient and the estimated hepatic blood flow was normal in most of them. Overall, saralasin induced a significant reduction of the mean arterial pressure, cardiac index and peripheral resistance. The decrease of the peripheral resistance was greater than that of the cardiac index. Six of the patients developed a marked reduction of the mean arterial pressure with low doses of saralasin (1--2.5 microgram/kg/min), and they had significantly higher plasma renin activity and lower mean arterial pressure than the remaining eight patients who showed a slight or no hypotensive response in spite of infusing saralasin up to a dose of 10 micrograms/kg/min. Overall, the decrease of the mean arterial pressure correlated directly with the baseline values of plasma renin activity. Angiotensin-II blockade induced a significant reduction of the wedged hepatic venous pressure. The hepatic blood flow did not show any significant change. The decrease of the wedged hepatic venous pressure was directly related to the reduction of the mean arterial pressure and also to the control plasma renin activity. Our study indicates that in most patients with cirrhosis, ascites and high plasma renin activity, arterial pressure is maintained by the effect of endogenous angiotensin II on the peripheral vasculature, and we suggest that a pre-existing arterial hypotension secondary to an arteriolar vasodilatation is the cause of renin release in these patients. Our results also show that angiotensin-II blockade is accompanied by a reduction of the post-sinusoidal hepatic vascular resistance.

Effects of somatostatin on hepatic and systemic hemodynamics in patients with cirrhosis of the liver: comparison with vasopressin

The effects of somatostatin on hepatic and systemic hemodynamics were investigated in 17 patients with chronic liver disease and severe portal hypertension during the hemodynamic assessment before elective portal-systemic shunt surgery. The injection of somatostatin (1.0 microgram/kg) caused a decrease of the wedged hepatic venous pressure, from 19.5 +/- SE 1.3 mmHg to 14.0 +/- 1.0 mmHg (p < 0.001). Injections of 0.5 and 2.0 microgram/kg had similar effects. During somatostatin infusion at a constant rate (7.5 microgram/min) there was a reduction of the wedged hepatic venous pressure (-17.0%, p < 0.001) and estimated hepatic blood flow (-17.5%, p < 0.01) but no significant changes in hepatic vascular resistance, cardiac output, systemic blood pressure, peripheral resistance, or cardiopulmonary pressures. In marked contrast to the selective action of somatostatin on splanchnic hemodynamics, vasopressin infusion (0.3 U/min) in 6 patients caused not only significant falls in the wedged hepatic venous pressure and estimated hepatic blood flow (-28.6% and -31.8%, respectively), but also significant changes in the systemic circulation, including a reduction of the cardiac output (-19.7%, p < 0.01) and heart rate (-12.6%, p < 0.01) and an increase of the arterial pressure (+18.8%, p < 0.01) and peripheral resistance (+46.8%, p < 0.01). These results show that somatostatin effectively reduces hepatic blood flow and portal pressure in patients with cirrhosis and severe portal hypertension, without altering the systemic circulation.

Plasma renin activity and urinary sodium excretion as prognostic indicators in nonazotemic cirrhosis with ascites

Azotemia is an ominous prognostic sign in cirrhosis with ascites. To investigate whether other renal disturbances are also prognostically significant, we studied the renin-aldosterone system and sodium excretion (UNaV) in 75 patients who had nonazotemic cirrhosis with ascites and related these to survival. On the basis of plasma renin activity patients were classified in two groups. Group I included 34 patients with normal renin activity (1.13 +/- 0.69 ng/mL . h) and Group II, 41 patients with high renin activity (7.46 +/- 3.86 ng/mL . h). The two groups differed significantly (p less than 0.001) in plasma aldosterone, UNaV, and wedged hepatic venous pressure but not in clinical features, liver function, glomerular filtration, and renal plasma flow. Patients of Group I lived significantly longer than those of Group II (the 50% survival rates were 28 months and 6 months, respectively). Survival curves obtained after grouping the patients according to UNaV (higher and lower than 10 meq/d) were almost identical to those obtained according to renin activity. The study results indicate that plasma renin activity and UNaV are of prognostic value in nonazotemic cirrhosis with ascites.

Use of piretanide, a new loop diuretic, in cirrhosis with ascites: relationship between the diuretic response and the plasma aldosterone level

Twenty patients with cirrhosis and ascites but no renal failure were given piretanide, a new loop diuretic, in order to investigate its efficacy and to relate the diuretic response with the pretreatment plasma aldosterone concentration. Eleven patients responded to piretanide 12 mg/day (equivalent in potency to 80 mg furosemide); there was no response in nine patients. Both groups were similar with regard to liver function, plasma urea, serum creatinine, plasma electrolytes, urine volume, and urine potassium concentration. The basal urinary sodium excretion was significantly higher in those patients who responded (23.6 +/- 5.7 mmol/day vs. 4.3 +/- 1.42 mmol/day; P < 0.01) (M +/- SE). Plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were normal or only slightly increased in patients who responded to piretanide (PRA = 1.22 +/- 0.20 ng/ml/h; PAC = 12.25 +/- 2.20 ng/100 ml) and very high in patients who did not respond (PRA = 8.71 +/- 1.18 ng/ml/h; PAC = 84.6 +/- 16.2 ng/100 ml) (P < 0.001). Patients unresponsive to piretanide 12 mg/day also failed to respond when the dose was increased to 24 mg/day. However, the addition of spironolactone, 150 mg/day, to piretanide was followed in these patients by a marked increase in diuresis and natriuresis. These results strongly suggest that the pre-treatment level of aldosterone is an important factor influencing the response to loop diuretics in patients with non-azotaemic cirrhosis and ascites.

[Neonatal aortic thrombosis]

A case of aortic thrombosis is reported in a 14 days old newborn after extensive review of the world literature is made. It was secondary to sepsis and hypercoagulability syndrome. Emphasis is placed on the early diagnosis, on the usefulness of the Doppler system when studying the vascular system as a non-invasive method in critically ill pediatric patients; likewise, on the determinant surgical procedure during the initial stages of the establishment of the aortic thrombosis.

Course of gentamicin nephrotoxicity

Metabolic balance and morphologic studies were performed on rats receiving gentamicin 100 mg/kg/day for a period of 8--10 days and during the recovery period. Daily urine flow rate increased with the administration of gentamiccin and remained elevated up to 20 days following the discontinuation of gentamicin, although BUN and plasma creatinine were virtually normal 10 days after the discontinuation of gentamicin. During the development of renal failure means daily electrolyte excretion remained normal. During the recovery period, however, sodium and potassium excretion exceeded control values while chloride and net acid excretion remained normal. Proteinuria developed during the administration of gentamicin and returned to normal 6--10 days after the discontinuation of gentamicin. Ten days of netilmicin administration (150 mg/kg/day) resulted in only mild tubular degeneration and no azotemia.

[Treatment of the syndrome of inappropriate antidiuretic hormone secretion with demethylchlortetracycline (author's transl)]

A patient with a syndrome of inappropriate antidiuretic hormone secretion secondary to an undifferentiated bronchogenic carcinoma with distant metastases was treated with demethylchlortetracycline. Up until recently, treatment of this syndrome was based on water restriction and when the plasma sodium concentration became extremely low, hypertonic saline solution administration. Recently it has been demonstrated that the antibiotic demethylchlortetracycline inhibits the action of the antidiuretic hormone on the renal tubules. The drug has been used successfully in five patients with the syndrome of inappropriate antidiuretic hormone secretion. The administration of 900 mg of demethylchlortetracycline per day for 7 days in our patient produced an increase of free water clearance, diuresis, plasma sodium concentration, and plasma osmolarity. Urinary excretion of sodium and urinary osmolarity declined. Furthermore, the neurological symptoms attributed to hyponatremia improved markedly. The patient lost 6 kg during treatment, probably because of negative water balance induced by demethylchlortetracycline. Even though the administration of demethylchlortetracycline did not produce significant decreases in the glomerular filtration rate or renal blood flow in our patient, it is advisable to control the renal function in individuals treated with this drug since it may on occasion determine renal insufficiency.

Renin, aldosterone and renal haemodynamics in cirrhosis with ascites

The interrelationships between the renin-angiotensin-aldosterone system, renal haemodynamics and urinary sodium excretion were investigated in fifty-six non-azotaemic cirrhotics with ascites. In twelve additional patients the renal renin secretion rate was also studied. Plasma renin activity and concentration and plasma aldosterone ranged from normal to very high values. There was a significant inverse relationship between plasma aldosterone and the urinary sodium excretion. Plasma aldosterone showed a highly significant direct correlation with plasma renin activity, and plasma renin concentration was closely and directly related to the estimated renin secretion rate. Neither plasma renin activity, plasma renin concnetration nor the estimated renin secretion rate correlated with the renal plasma flow or the glomerular filtration rate. These results suggest that in non-azotaemic cirrhosis with ascites the renin-angiotensin-aldosterone system is an important factor influencing sodium excretion, increased plasma renin and aldosterone concentrations are mainly due to an increased secretion rate, and total renal perfusion is not a major factor influencing renin secretion.

Renal failure associated with demeclocycline in cirrhosis

Three patients with cirrhosis, ascites, and dilutional hyponatremia were treated with demeclocycline in an attempt to correct the abnormal water retention. Demeclocycline administration (600 to 900 mg/day for 8 to 9 days) resulted in [a] increased blood urea nitrogen and plasma creatinine concentrations; [b] reduction of the inulin clearance by between 63% to 78% and of paraaminophippurate clearance by 36% to 77%; and [c] an impairment of the renal concentrating ability. Urine osmolality decreased to hypotonic levels, but polyuria did not appear, probably because it was prevented by the reduction of the glomerular filtration rate. Renal failure was reversible on withdrawal of demeclocycline. No other causes than demeclocycline administration could be found to explain the reduction of the glomerular filtration rate and the estimated renal plasma flow.

Functional renal failure and haemorrhagic gastritis associated with endotoxaemia in cirrhosis

Forty-three patients with cirrhosis and ascites, 21 with normal renal function, 10 with a progressive functional renal failure (FRF), and 12 with a steady FRF, were investigated for the presence of endotoxaemia by the Limulus lysate test. Endotoxaemia was found in nine patients with FRF and in none of the 21 with normal renal function (P less than 0-01). A positive Limulus test was almost exclusively associated with a progressive FRF (eight of 10 patients) and all but one of them died. Renal function improved as endotoxaemia disappeared in the survivor. Endotoxaemia was also associated with haemorrhage due to acute erosions of the gastric mucosa, being present in six of the seven patients who had this complication. Intravascular coagulation was not found in any patient. The Limulus test was positive in the ascitic fluid in 18 of 21 patients tested, although only two of them had peritonitis. These results suggest that endotoxaemia may play a critical role in the development of progressive renal failure and haemorrhagic gastritis in cirrhosis, and emphasise the potential risk of procedures involving reinfusion of ascitic fluid.

Effect of sodium nitrate loading on electrolyte transport by the renal tubule

Effects of sodium nitrate were compared with sodium chloride loading on transport of electrolytes by the nephron. Maximal levels of free water clearance/clomerular filtration rate (CH2O/GFR) averaged 8.4% with nitrate loading and 14.4% with saline loading. Since ethacrynic acid and chlorothiazide exert their major natriuretic effect in the distal nephron, the increment in Na ad Cl reabsorbed beyond the proximal tubule. The administration of these agents resulted in an increase in fractional sodium excretion (CNa/GFR) of 21.1%, urinary sodium excretion (UNaV) of 1,126 mueq/min, and urinary chloride excretion (UClV) of 848 mueq/min during nitrate loading compared with an increase in CNa/GFR of 37.6%, UNaV of 2,362 mueq/min, and UClV of 2,397 mueq/min during saline loading. The smaller diuretic-induced increment in Na and Cl excretion in the nitrate studies suggests, as do the hydrated studies, that less Cl and Na are reabsorbed in the distal nephron during nitrate than saline loading. At every level of UNaV, fractional bicarbonate reabsorption was higher, urine pH was lower, and urinary potassium excretion (UKV) was higher in the nitrate studies. Thus, compared with saline loading, sodium nitrate decreases chloride and sodium reabsorption in the distal nephron. The higher hydrogen and potassium secretion in the nitrate studies may be consequent to the decreased ability of the distal nephron to reabsorb chloride.

Clinical types and drug therapy of renal impairment in cirrhosis

Four separate types of renal failure in cirrhosis are described: functional renal failure; diuretic induced uraemia; acute tubular necrosis; chronic intrinsic renal disease.

Functional renal failure may arise spontaneously or be precipitated by such factors as haemorrhage, surgery, or infection. It carries a poor prognosis but preliminary results of treating this condition with plasma volume expansion in combination with high doses of furosemide are encouraging.

Familial clustering of hepatitis B antigen: a study in relatives of patients with liver diseases and hepatitis B antigenaemia

Twelve of the 100 family contacts of 29 patients with transient and persistent hepatitis B antigenaemia were found to be positive for hepatitis B antigen (HBAg). No relation was found between familial clustering and the nature of liver disease or the duration of antigenaemia in the index cases.Eight affected relatives were apparently healthy carriers of HBAG, one had cirrhosis, and three (in the same family) developed acute viral hepatitis.The absence of parenteral exposure in the HBA,-positive family contacts and the identity in antigenic determinants d or y with those of the index cases, suggest a non-parenteral spread of HBAg in families of patients with HBAg-associated liver diseases.