Role of the control of phosphate in the progression of chronic renal failure

In order to control the progression of chronic renal failure through the maintenance of low-normal levels of serum phosphate, 10 patients (group I) were followed over a period of 10 months. They were maintained on a low phosphate diet and 12 g/day of aluminum hydroxide. Under this treatment, the serum phosphate decreased significantly compared to the phosphate levels determined prior to initiation of treatment, and compared to the serum phosphate levels of 10 controls with the same degree of renal failure (group II) but receiving conventional treatment. Despite the maintenance of normal levels of serum phosphate in group I, serum creatinine increased in the same proportion as in group II. A paired t test did not show any difference between the progression of the renal failure before or after the control of serum phosphate.

The role of urinary PGE2 and renin-angiotensin-aldosterone system in the pathogenesis of essential hypertension

In a group of 26 patients diagnosed as essential hypertensive (EH) and in a control group (CG) of 27 normotensive volunteers the urinary excretion of PGE2, plasma renin activity (PRA) and plasma aldosterone were measured. EH patients were classified into normoreninemic (NREH) (n = 21) and hyporeninemic (LREH) (n = 5) by the response of PRA to the combined stimuli of ambulation and furosemide. Urinary PGE2 excretion was higher in NREH than in CG (p less than 0.05) while LREH showed values lower than in CG (p less than 0.001). Plasma aldosterone levels were similar in the three groups. In CG and EH patients PRA and urinary PGE2 were closely related (CG r = 0.516, p less than 0.05, EH patients r = 0.674, p less than 0.001). Indomethacin administration induced a decrease of PGE2 in both CG (n = 8) and NREH (n = 8) (p less than 0.01). In contrast, indomethacin induced no changes in PGE2 excretion of LREH (n = 5). Furthermore in the group of patients with NREH indomethacin induced a significant increase in blood pressure (p less than 0.01) and body weight (p less than 0.01) while glomerular filtration rate, 24 hour natriuresis PRA and plasma aldosterone decreased (p less than 0.01). On the contrary, in LREH indomethacin did not alter any of the parameters measured. These results indicate that LREH and NREH may be regarded as two different populations distinguishable not only by different secretion of PRA but also by different excretion of PGE2 in urine and by their characteristic response to indomethacin.

Role of renal prostaglandin E2 in chronic renal disease hypertension

The role played by renal prostaglandin E2 in the maintenance of hypertension in chronic renal disease has been investigated through studying the response of body weight, blood pressure, glomerular filtration rate (GFR), 24-hour natriuresis, plasma renin activity (PRA), plasma aldosterone and urinary PGE2 excretion to the administration of indomethacin (2mg/kg daily, during 3 days). A group of 37 patients diagnosed as having chronic renal parenchymatous disease with creatinine clearance above 25 ml/min was included in the study. 21 of them were hypertensive (BP greater than 160/95). 27 normotensive volunteers were also studied and considered as the control group. The initial study disclosed similar levels of PGE2, PRA and plasma aldosterone in volunteers, normotensive patients and hypertensive patients, although the sodium intake was lower in the last two groups. A positive correlation between PRA and urinary PGE2 was found both in normotensive (r = 0.507, p less than 0.01) and in hypertensive patients (r = 0.609, p less than 0.01). The administration of indomethacin induced a diminution of PRA, plasma aldosterone and urinary PGE2 levels together with an increase in diastolic blood pressure (p less than 0.05-0.01) in both volunteers and patients. The remaining parameters measured did not change in volunteers or in normotensive patients. On the contrary, in hypertensive patients, during indomethacin administration, lower values of creatinine clearance (p less than 0.005) and 24-hour natriuresis (p less than 0.05) together with an increase in body weight (p less than 0.01) were observed. These results point to the existence of a protective role of renal prostaglandin E2 upon renal function when hypertension appears in the course of chronic renal parenchymatous disease.

The value of ultrasonic scanning in the differentiation of acute post-transplant renal failure

In 43 renal transplant patients studied by ultrasonography there were 32 episodes of acute rejection and 17 of acute tubular necrosis. The size of the kidney increased in all cases. However, in 75 per cent of the patients with acute rejection the central echoes of the renal sinus increased conspicuously, while in 77 per cent of those with acute tubular necrosis the echogenicity of the central sinusal complex decreased. These findings may be expressions of different pathological lesions at the renal sinus level in patients with acute rejection and acute tubular necrosis, which would modify the acoustic interphase. Therefore, we have found panniculitis, vasculitis, thrombosis and inflammatory cellular infiltration of the urinary collecting systems to be significant in patients with acute rejection but not in those with acute tubular necrosis. Ultrasonography can be an adjuvant instrument for the sometimes difficult differential diagnosis between acute tubular necrosis and acute rejection immediately after transplantation, and also for the diagnosis of acute rejection whenever it appears.

[Hypertensive crisis. Clinical and therapeutic study of 130 cases (author's transl)]

The clinical aspects and response to therapy of 130 hypertensive emergencies are reviewed in this report. According to the main features of the clinical picture, the patients were divided into neurologic, cardiac or mixed emergencies. The patients were evaluated with clinical examination, fundoscopy, routine biochemistry, ECG, and chest radiograms. According to the response of the blood pressure to the administration of hypotensive drugs, the patients were divided into two groups: group I, with good response to a single drug associated to frusemide, and group II, with good response to two or more drugs associated to frusemide. Neurologic emergencies appeared in 55 patients (42% of total), and cardiac emergencies in 45 (34%), the initial blood pressure beeing higher in the first group (p less than 0.005). The fundus showed hypertensive retinopathy degrees III-IV in 55% of the patients. Patients in group I had less elevation of the initial blood pressure, showed a better response to therapy, and had only mild side effects from the administered drugs. Group II had a mortality of 11% and, as expected, showed more complications due to side effects. The frequency of appearance of toxic side effects from the drugs given is reviewed, and a therapeutic schedule is proposed.

[Familial and hereditary mesangial glomerulonephritis with IgA deposits (author's transl)]

Idiopathic mesangial glomerulonephritis with IgA deposits was observed in two relatives, father and son, in a family of 5 members. In the father the disease started at age 43 with relapsing macroscopic hematuria, proteinuria, renal failure and hypertension, with a progressive course in the ensuing four years. The affected son, the oldest of three brothers, developed relapsing macroscopic hematuria at age 16; two years later renal function was normal and there was no hypertension, but microhematuria persisted without proteinuria. The mother and the other two brothers had no clinical or biological signs of renal disease. Serum immunoglobulins (IgG, IgA, and IgM) and complement (C3, C4, C3 proactivator) were normal in the patients and their relatives. Histocompatibility typing demonstrated the presence of HLA-Bw35 in the father and the two unaffected sons, being negative in the mother and the affected son. The analysis of HLA-Bw35 in 23 patients with IgA mesangial glomerulonephritis gave positive results in 30% of them, while the control group had a positivity of 15% (p non significant with the X2 test). The present observations suggest that IgA mesangial glomerulonephritis is a potentially familial and hereditary renal disease. HLA-Bw35 antigen appears not to be a genetic marker of the disease in our geographical area.

[Low dose clofibrate in the treatment of hypertriglyceridemia in hemodialysis patients (author's transl)]

Sixteen patients on regular hemodialysis were treated with clofibrate, 500 mg three times a week for six weeks. A sustained and significant reduction of serum triglycerides occurred in thirteen patients. Serum cholesterol was also significantly reduced, although to a lesser degree. Predialysis levels of blood urea nitrogen, creatinine, and uric acid were significantly elevated during the treatment period and returned to previous levels after withdrawal of the drug. The incidence of side-effects was elevated. Five patients complained of nausea and upper abdominal discomfort, while four patients had muscle pain. Several muscle enzymes were elevated in a high percentage of patients, returning to basal values after discontinuation of the drug. It is concluded that clofibrate, although it is effective in lowering serum triglycerides in patients on hemodialysis, should not be used in such patients.

Hypouricemia by defect in the tubular reabsorption

Two patients with hypouricemia with high levels of uric acid in their urine were given pyrazinamide and probenecid. The uric acid clearance decreased to low or normal values after pyrazinamide administration. In both cases, probenecid produced a slight increment in the uric acid excretion. This type of response suggests a defect in the reabsorption component. It is tempting to speculate on a postsecretory reabsorption defect based on the results of pyrazinamide and probenecid tests.

Alterations induced by large doses of furosemide in chronic renal insufficiency

Eleven patients with different degrees of renal failure with creatinine clearances between 7 and 32 ml/min have been studied. After a standard water overload and control periods of clearances, furosemide 1 g was given/i.v. There followed significant increase of renal plasma flow and glomerular filtration rate. In one case the increase was maintained during a follow up period of 3 hours. A significant increase was evident in phosphate, uric acid, sodium, potassium, and calcium clearances, as well as an increase in the sodium delivery to the distal nephron and a decrease in tubular reabsorption of phosphate. All this may be interpreted as the result of renal vasodilation induced by furosemide and its effect upon the proximal tubule and on Henle's loop.

Renal vein thrombosis, nephrotic syndrome, and focal lupus glomerulonephritis

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Acute renal failure after use of diesel fuel as shampoo

After washing his hair with diesel fuel a 28-year-old patient developed acute renal failure (ARF) and oliguria requiring hemodialysis. The patient recuperated completely. In the absence of other causal factors, we believe that the absorption of the diesel fuel components, either through the respiratory tract or through the skin can be considered to be the cause of the ARF. In spite of the extended everyday use of petroleum distillation products, cases of acute intoxication are infrequent. Even rarer are cases in which these products occasion ARF.

Effects and interactions of furosemide and acetazolamide on tubular function in rat kidney

Furosemide and acetazolamide effects on tubular function in rat kidney have been studied by micropuncture. Furosemide produced a marked rise in fractional proximal fluid reabsorption when urine loss was not replaced, and sodium excretion rose significantly indicating a distal effect. If urinary losses were replaced proximal fractional reabsorption was depressed and fractional sodium excretion increased more than 60%. After replacing urinary losses, acetazolamide had a greater depressive effect on proximal tubular fluid reabsorption than furosemide but sodium excretion values were about 1/3 of those obtained with furosemide. Superimposition of one drug during the action of the other resulted in potentiation of proximal inhibition, suggesting a different mechanism of action. The changes observed in potassium excretion are of great interest. Separately, furosemide or acetazolamide produced kaliuresis. When furosemide was administered during acetazolamide diuresis, however, potassium excretion was reduced despite the sharp rise in sodium excretion.

[Tubular permeability maintained in post-ischemic acute renal failure (author's transl)]

The effect of nearly total renal ischemia during a two hour period on glomerular filtration and urine composition was studied in relation to tubular permeability and tubular obstruction, two mechanisms that could explain renal insuficiency after iscehmia. Studies on creatinine clearance, micropuncture and microinjection of 14C-inulin into the proximal tubules by means of a hydraulic system were performed before and after the period of ischemia. Thirty minutes after the withdrawal of arterial obstruction, the animals exhibited a maintained diuresis, 50 per cent reduction in glomerular filtration in the superficial nephrons and in the total kidney, a reduction in the proximal fractional absorption of water, and also an increase in the urinary elimination of sodium. The glomerular filtrate of cortical nephorns obtained by micropuncture in anterior areas of the proximal tubules did not differ significantly from the one obtained by micropuncture in more distal areas. The inulin injected into the proximal tubules of a kidney was entirely eliminated by it.