Immunosuppressive treatment of the nephrotic syndrome due to mesangial lesions

To assess the effectiveness of an intensive immunosuppressive regimen on the nephrotic syndrome due to mixed membranous and mesangial lesions, we studied 18 patients with nephrotic syndrome and miscellaneous histologic features characterized by mesangial proliferation and sclerosis, non-specific basement membrane changes such as thickening, fraying and scalloping, in the absence of extensive immune complex deposition by immunofluorescence. The patients were treated with an immunosuppressive regimen that combined prednisone and cyclophosphamide for at least 6 months with the following schedule: 1) induction with prednisone daily 250 to 750 mg i.v. for 3 to 8 days, plus cyclophosphamide 100 to 200 mg p.o. daily; 2) maintenance with prednisone 100 to 200 mg p.o. in alternate days for 30 to 75 days, and cyclophosphamide as before; 3) tapering, with prednisone in alternate day regimen, reduced on average by 25 mg every month, plus cyclophosphamide as before; 4) discontinuation of cyclophosphamide and slow withdrawal of prednisone. Treatment lasted on average 9 months, with an average cumulative dose of prednisone of 9.2 g and of cyclophosphamide of 26.7 g. At the end of treatment, 14 patients had a complete remission and 4 remained stable. On longer follow-up, one out of these 4 patients, who had renal failure before treatment, subsequently progressed to end-stage renal disease. Nine patients relapsed after an average remission of 6 years. Eight of them remitted completely on a repeat cycle. One patient refused the retreatment and progressed to end-stage renal disease within one year. After an average follow-up of 7.3 +/- 1.1 years, plasma creatinine for the whole group had fallen from 138 +/- 26 to 103 +/- 20 mumol/l and proteinuria from 6.7 +/- 0.7 to 0.4 +/- 0.2 g/d (p < 0.001). In conclusion, in patients with these forms of nephrotic syndrome this immunosuppressive regimen is highly effective in inducing remission, in preventing progression to end-stage renal disease and in treating relapses.

Intracranial volume receptors: possible role on ADH homeostatic control

Volume receptors are situated in many organs and are capable of modulating ADH secretion. We have evaluated the variation of plasma ADH concentration after an experimentally induced increase of cerebrospinal fluid (CSF) pressure (PCSF). The experiment was performed in controlled environmental conditions to avoid pain or stress-related ADH release. In 15 rats (10 experimental, 5 control) a cannula was positioned in the left cerebral ventricle: in the experimental group artificial CSF was infused at a rate of 0.6 (microliter/min for 6h: this manoeuvre, in a separate set of animals obtained an increase from 13.03 +/- 0.8 to 25.4 +/- 2.5 cmH2O of PCSF. The same conditions were reproduced in the control group without infusion into lateral ventricle. At the end of the experiment, plasma ADH had fallen significantly in the experimental group from 18.9 +/- 4.8 to 11.9 +/- 2.3 pg/ml (p < 0.05), while it was not changed in the control group (from 25.5 +/- 13.7 to 23.7 +/- 16.2 pg/ml). Heart rate, arterial pressure, plasma Na+ and osmolality, did not change significantly. Plasma K+ fell significantly in both groups: from 5.5 +/- 0.6 to 4.3 +/- 0.3 (p < 0.05) and from 5.4 +/- 0.7 to 4.3 +/- 0.15 mEq/l (p < 0.05) in the experimental and control group respectively. Plasma creatinine was normal, checked only at the end of the experiment. Our results demonstrate that a relationship exists between PCSF variations and plasma ADH concentration. We believe this relationship is due to the pressure receptors in the cerebral ventricles or in structures connected to it, such as the inner ear, and we hypothesize the existence of a control system of body fluids, more diffused than though to be, up till now.

Immunosuppressive treatment of the glomerulonephritis of systemic lupus

To evaluate the results, the long-term prognosis and the rates of complication of an immunosuppressive regimen with corticosteroids and cyclophosphamide in the treatment of the nephritis of systemic lupus erythematosus, 21 patients with lupus glomerulonephritis were studied. Renal biopsies were performed in 17/21 of them and indicated diffuse proliferative (6 patients), diffuse mesangial (4) and membranous (7) glomerulonephritis. Treatment was structured in 4 phases: 1) induction with methylprednisolone 250 mg i.v. for 7-14 days, and cyclophosphamide 100-200 mg p.o., q.d., or 20 mg/kg i.v. every 28 days; 2) maintenance with prednisone p.o., 2 mg/kg q.o.d. for 45 days, and cyclophosphamide as before; 3) tapering, with reduction of prednisone by 15% each month for 4 months; 4) indefinite maintenance with prednisone slowly tapered to the least effective q.o.d. dose and cyclophosphamide discontinued after six months of treatment. This cycle was repeated in the event of a relapse. After a first immunosuppressive cycle, 20/21 patients achieved remission of glomerulonephritis. Plasma creatinine fell from 97 +/- 6 to 80 +/- 3 microMol/l (p < 0.01). Proteinuria fell from 2.1 +/- 0.4 to 0.2 +/- 0.4 g/d (p < 0.0001) and the nephrotic syndrome, present in 8 patients, disappeared. After an average of 20 +/- 7 months, 8 patients relapsed: all remitted again after a repeat cycle, but 1 later progressed to end-stage renal failure during pregnancy. After an average of 56 months 4 out of these 8 patients relapsed again: 1 progressed to end-stage renal disease following an abortion and 3 remitted completely after a third cycle. Thus, 18 out of 21 patients are presently in remission with an average dose of prednisone of 13.7 mg/day after an average follow-up of 52 +/- 38 months (range 2 to 156). Three patients are presently off treatment. In 16 patients with extended follow-up of 2 to 13 years, anti-nuclear antibodies, anti-DNA antibodies, albuminuria and cylindruria fell below post-cycle levels (p < 0.001 for all). We conclude that intensive immunosuppression with steroids and cyclophosphamide can achieve excellent long-term results in the treatment of systemic lupus with glomerulonephritis.

Immunosuppressive treatment of membranoproliferative glomerulonephritis

The treatment of membranoproliferative glomerulonephritis (MPGN) is considered by most authors as unrewarding, and the disease progresses to end-stage renal disease (ESRD). We studied the effectiveness of a new immunosuppressive (IS) regimen by analyzing the rates of remission, relapse and progression to ESRD in 19 patients with MPGN. The treatment consisted of 4 phases: (1) induction with intravenous boluses of methylprednisolone plus cyclophosphamide (CPM) orally; (2) maintenance with oral prednisone (PDN) in an alternate-day regimen and CPM in a daily oral dose; (3) tapering during which PDN alone was slowly decreased; (4) discontinuation when CPM was omitted and PDN slowly withdrawn according to the steroid withdrawal schedule. At the end of the treatment that lasted on average 10 +/- 1 months, 15 patients remitted, 3 improved and 1 progressed. There were 8 relapses in 6 patients: 4 in 3 patients were treated with repeat cycles and remitted completely. Four patients who had relapsed after 4, 8, 11 and 13 years of remission refused retreatment and progressed rapidly to ESRD. All patients treated and retreated after relapsing had remissions, while renal failure and disease progression occurred in 1 patient only. Plasma creatinine averaged, in the whole group, 165 +/- 26 before, 156 +/- 30 after treatment and 224 +/- 57 microM/l at the end of 7.4 +/- 0.8 years of follow-up. An intensive IS regimen combining steroids and alkylating agents in high doses and for a prolonged time is effective in inducing remission and halting progression to ESRD in patients with MPGN.

Heterogeneous derangement of cellular sodium metabolism in Bartter's syndrome. Description of two cases and review of the literature

The basic tubular alteration present in Bartter's syndrome is still a subject of controversy. The possibility that a generalized defect in transmembrane ion transport underlies the disease has been extensively investigated. Previous evaluations of cellular sodium metabolism in Bartter's patients showed extremely variable findings. In the present study we have examined in red blood cells of two patients with Bartter's syndrome the intracellular Na+ and K+ concentrations, the activity of ouabain-sensitive Na+/K+ pump, furosemide sensitive Na+/K+ cotransport, Na+/Li+ countertransport, and the rate constant of Na+ and K+ passive permeability. We have compared these values with those of a control group. Ouabain-sensitive Na+/K+ pump activity was decreased in both patients, whereas Na+/Li+ countertransport was activated. One of the patients also exhibited markedly decreased intraerythrocyte K+ concentration and decreased furosemide-sensitive Na+/K+ cotransport. The other had increased Na+/K+ cotransport activity and Na+ passive permeability. Intracellular Na+ and passive permeability to K+ were normal in both subjects. Our results are partially consistent with previously reported observations, and indicate the existence of heterogeneous alterations of erythrocyte sodium transport systems in patients with Bartter's syndrome. Although some of these alterations could be secondary to the electrolyte metabolism derangements of this disease, others might be genetically transmitted and could cause the different renal tubular defects shown in Bartter's disease so far.

Sodium reabsorption by the Henle loop in humans

In a previous study, we described a new method [3] to measure Na reabsorption by each segment of the human nephron independently. Reabsorption was expressed as equivalent volumes of solute-free water (CH2O) generated by the loop of Henle (CH2O-HL) and by the distal tubule (CH2O-DT), and dissipated by back diffusion (BD) across collecting ducts (CH2O-BD). These data were obtained during maximal water diuresis (MWD). The present study was undertaken to calculate CH2O-HL by experiments performed during maximal antidiuresis (MA). For this purpose, a new theoretical approach was devised, described by algebraic equations which allowed calculations of segmental transport during MA alone, where only CH2O-HL could be calculated independently. The study was performed on 14 normal volunteers who were studied twice by clearance measurements, firstly during MWD and again during MA. In each experiment, clearance periods were performed during baseline conditions and during the administration of furosemide (0.7 mg/kg bolus injection followed by 0.06 mg/kg/min maintenance infusion). From the values measured during either condition, segmental reabsorption was calculated. During MWD, CH2O-HL averaged 19.4 + 10.4, during MA 20.4 + 8.0 ml/min/GFR X 100; p greater than 0.05. The paired measurements were significantly correlated (r = 0.80; p less than 0.01). These data demonstrate that CH2O-HL obtained with the original theory is a reproducible result that can be confirmed with independent measurements obtained during different experimental conditions. Thus, measurements of segmental Na transport in the human nephron are feasible and can contribute important informations on disease states.

[Diuretic and antihypertensive activity of azosemide]

The results of a study conducted using a new loop diuretic, Azosemide, on a group of 45 patients suffering from hypertension and oedema are reported. Thirty patients were studied in an open trial and in association with other drugs. The remaining 15 exclusively hypertensive patients, were studied in a controlled trial against Indapamide. The patient's standing and recumbent arterial pressure was monitored and all were given periodic weight checks. In the 1st group, Azosemide brought about a significant reduction in arterial pressure, without modifying body weight, but caused considerable weight loss (from 71 to 64 kg) (P less than 0,01) in the oedema patients without altering arterial pressure. In the 2nd group of hypertensive patients, a significant fall in arterial pressure (from 166 to 138 mmHg) was observed, most notably after Azosemide treatment. None of the patients revealed side effects, or alterations in laboratory parameters. It is therefore suggested that Azosemide--given its effectiveness and ease of application--is particularly useful for the diuretic treatment of hypertensive and oedematous patients.

The role of prostaglandins in Na retention of porta-cava shunted rats

The importance of prostaglandins (PG) in Na and water retention of liver cirrhosis was studied in rats with porta-cava shunt (PCS) compared to control, non-shunted animals. Balance studies were performed in metabolic cages with diets of high, normal and low Na. An experimental phase, during which the animals received either 5 mg X kg-1 of indomethacin daily or placebo, was preceded by a control period and followed by a post-indomethacin period identical to the control phase. In each diet, indomethacin, but non placebo, caused a positive Na balance, correlated with Na intake, which in overall pooled data amounted to -1453 +/- 255 muEq in PCS rats, significantly larger than that measured in controls, of -295 +/- 320 muEq (P less than 0.01). This was attended by a reverse change in K balance of -35.6 +/- 349 muEq versus -1566 +/- 582 muEq (P less than 0.01); glomerular filtration rate (GRF) was unchanged. These data demonstrate that PGs contribute to the control of Na homeostasis in the presence of PCS.

Studies on the nephron segment with reduced sodium reabsorption during starvation natriuresis

The segment of the nephron where carbohydrate deprivation depresses Na transport leading to natriuresis was sought by a new clearance technique designed to measure segmental reabsorption in each portion of the human renal tubule. Experiments were performed during maximal water diuresis before and 4 days after carbohydrate withdrawal. Proximal reabsorption had fallen from 70 +/- 4 to 60 +/- 5 ml X min-1, p less than 0.05, by the 4th day of sugar deprivation, accounting for the natriuresis and the associated weight loss of 1.8 kg. By the 4th day of fasting, when Na excretion had returned to control levels, GFR had fallen nonsignificantly from 99 +/- 6 to 95 +/- 5 ml X min-1, while Na reabsorption along distal segments had risen. In fact, Na transport, expressed by the equivalent volumes of solute free-water generated, rose from 17.4 +/- 3.4 to 23.6 +/- 2.1 along the ascending limb of Henle's loop, and from 8.1 +/- 0.8 to 9.2 +/- 1.3 ml X min-1 X GFR-1 X 100 along the distal tubule. Thus, analysis of segmental Na transport by this method discloses that starvation natriuresis is a proximal tubular event, progressively counterbalanced by enhanced Na reclamation in more distal sites. Volume contraction and the attendant fall in GFR concur to curb delivery out of the proximal tubule which is matched by enhanced distal Na reabsorption till a new steady-state excretion is attained.

Experimental dissociation of the effects of prostaglandins on renal sodium and water reabsorption by cyclo-oxygenase inhibitors in the rat

1 The relative importance of the effect of prostaglandins on renal sodium and water reabsorption was assessed in rats. 2 Clearance experiments were performed on 24 anaesthetized rats divided into 3 groups. Each group was infused throughout either with Ringer solution at 9 ml/h (Protocol I), or at 3 ml/h (Protocol II) or with hypotonic fluid at 5 ml/h (Protocol III). Clearance periods were performed before and after intravenous injection of indomethacin (5 mg/kg) and then of aspirin (20 mg/kg). The natriuretic response to different degrees of volume expansion was not modified during the action of the inhibitors. 3 When baseline urine osmolality (Uosm) was high (Protocol II) no further increase occurred in the presence of prostaglandin inhibition. Conversely, Uosm rose from 771 +/- 134 to 1356 +/- 414 and from 575 +/- 245 to 841 +/- 407 mosm/kg (P less than 0.05) in Protocol I and Protocol III respectively, when antidiuretic hormone secretion was inhibited by the higher degree of volume expansion. 4 There was a significant correlation between the change in urine flow rate induced by cyclooxygenase inhibitors and the attendant variations in Na excretion, r = 0.42, n = 41, P less than 0.01. 5 Thus, prostaglandins affect Na loss during saline load as a side effect of their action on water permeability. They could play an important role in volume depletion by counterbalancing the large secretion rate of renal vasoconstrictors.

Muscarinic receptor blockade by pirenzepine: effect on prolactin secretion in man

The effect of pirenzepine, a muscarinic receptor blocker which does not cross the blood brain barrier, on basal and TRH-stimulated prolactin (PRL) secretion in normal subjects was studied. Administration of 75 mg oral pirenzepine had no effects on prolactin levels in male subjects whereas it significantly reduced prolactin in females. No effect on TRH induced prolactin secretion was observed.

Blunting of furosemide diuresis by aspirin in man

Experiments were performed on humans to study the blunting on the diuretic action of furosemide by prostaglandin synthetase inhibitors. Maximal water diuresis was instituted. At the peak of urine flow, clearance periods were performed during baseline conditions and repeated after the injection of aspirin and, subsequently, of furosemide. Control subjects did not receive aspirin. Urine flow rate (V), Cosm, and Na excretion (UNa) . V were significantly lower when the administration of the diuretic had been preceded by that of aspirin. In the absence of furosemide, however, aspirin did not influence renal hemodynamics nor Na and water reabsorption. Therefore, the same experimental protocol was repeated in paired experiments where each normal subject served as his own control, being studied twice, in the presence and absence of aspirin, respectively. The average changes in water and Na excretion induced by furosemide were not different when the patients were pretreated with aspirin as compared with those measured in the absence of prostaglandin inhibition. Changes occurring in individual experiments were significantly correlated (r = 0.95, P less than 0.01) with those in calculated furosemide clearance. Since aspirin, indomethacin, and meclophenamate are secreted by the organic acid transport system of the proximal tubule, competition for a common secretory mechanism, rather than prostaglandin inhibition, could mediate the blunting of furosemide diuresis.

Prolactin secretion in man following acute and long-term cimetidine administration

In 20 patients with duodenal ulcer we measured serum prolactin levels following acute and long-term cimetidine administration. In addition, in 20 healthy volunteers we studied the effect of pre-treatment with bromocriptine, meterogline, nomifensine and cryroheptadine on cimetidine-induced prolactin release. Intravenous cimetidine stimulated prolactin secretion in patients and in normal subjects. In the latter, bromocroptine and metergoline pre-administration blunted the release of prolactin in response to iv cimetidine whereas nomifensine and cyproheptadine were ineffective. Long-term treatment with cimetidine (1.2 g daily for 3 months) had no effect on prolactin secretion in the 20 patients studied. No incidence of gynaecomastia, galactorrhoea or disorders of the menstual cycle was observed.

Oxdralazine, a new peripheral vasodilator, combined with propranolol and hydrochlorothiazide: a rational approach to antihypertensive treatment

Forty-three patients suffering from hypertension of different origin (chronic renal failure, gout, or idiopathic) were treated with propranolol (121 +/- 12 mg q.d.) plus hydrochlorothiazide (50 mg q.d.) for 75 +/- 9 days. Blood pressure did not return to normal limits in 15 patients, who were continued on the same protocol plus 10 to 50 mg oxdralazine q.d. After an average of 68 +/- 35 days blood pressure fell from 180/110 mm Hg to 145/90 mm Hg without orthostatism, significant side effects, or changes in GFR. This combination seems particularly successful since propranolol will prevent the undesired rise in cardiac output due to oxdralazine as well as the activation of the renin-angiotensin axis due to diuretics. Thus, the antihypertensive properties of each agent will be enhanced by a reduction in side effects by the associated drug, resulting in optimal blood pressure control.