Effects of dopamine prodrugs and fenoldopam on glomerular hyperfiltration in streptozotocin-induced diabetes in rats

The effects of dopamine (DA) prodrugs (L-dopa and gludopa) and of a D1-selective agonist (fenoldopam) on glomerular hyperfiltration were studied in the early stage of diabetes in rats. Wistar rats received one injection of streptozotocin (STZ) and were treated 1 week later with L-dopa (2 x 10 mg/kg/day, s.c.), gludopa (2 x 3 or 2 x 10 mg/kg/day, s.c.), or fenoldopam (2 x 0.3 or 2 x 1 mg/kg/day, s.c.). Their renal functions were compared with those of untreated diabetic and nondiabetic control rats. STZ injection led to hyperglycemia that was kept moderate (20-25 mmol/L) by daily insulin therapy (2-4 U of NPH insulin). Within 2 weeks, glomerular hyperfiltration (polyfructosan clearance) developed in diabetic rats (30% increase vs. nondiabetic control). A rise in renal plasma flow (PAH clearance) was sometimes observed. One week of treatment with either L-dopa, gludopa, or fenoldopam normalized the glomerular filtration rate and decreased filtration fraction. These corrections occurred despite similar metabolic disturbance and kidney hypertrophy. Gludopa was less well tolerated by diabetic rats than L-dopa. Results with L-dopa showed that the normalization of glomerular hyperfiltration was linked to DA synthesis and stimulation of D1 receptors, since it was reversed by carbidopa, a dopa decarboxylase inhibitor, and by SCH 23390, a D1-selective antagonist. These data show that DA prodrugs and a D1 agonist can suppress diabetic glomerular hyperfiltration in the very early course of the disease in rats.

[Use of erythrocytapheresis in a pregnant woman with sickle cell anemia]

A case is reported of a 23 yr old pregnant woman from Zaire in whom homozygous sickle-cell disease was discovered at her first obstetrical visit at 25 week amenorrhea. She had had two previous pregnancies: the first one had been voluntarily interrupted; the second one went to term, but the child, born in a state of apparent death, died on the third day. Despite severe normocytic anaemia (5 mmol.l-1 haemoglobin, 2.9 T.l-1 erythrocytes, 0.25 haematocrit, 93 fl mean globular volume), she was symptomless. The diagnosis was confirmed by haemoglobin electrophoresis: 0 haemoglobin A (HbA) and 0.854 haemoglobin S (HbS). Because foetal growth and maturation appeared satisfactory, no procedure to increase the HbA/HbS ratio was used before the 37th week of amenorrhea. At that time, erythrocytapheresis was carried out using a discontinuous flow cell separator. Eight phenotyped red cell packs without leukocytes (removed by filtration) were transfused; at the end of the procedure, there was 0.67 HbA and 0.25 HbS. At 39 week amenorrhea, haemoglobin electrophoresis gave 0.43 HbA and 0.47 HbS. No further treatment was therefore given. At the 40th week, she gave birth to a healthy girl, Apgar score 10 at 1 min. She was given two further red cell packs at start of labour, because her haemoglobin level had fallen to 6.4 mmol.l-1. In the immediate postpartum, her HbS level was 0.38. The aims, advantages and disadvantages of the different techniques available for the treatment of homozygous sickle-cell anaemia in pregnancy are discussed.

[Aztreonam treatment of severe infections caused by gram-negative aerobic bacilli]

Twenty nine patients of an intensive care unit (9 women and 20 men), aged 63.9 +/- 15.8 years, with a mean body weight of 62.5 +/- 11.8 kg were treated during 9.4 +/- 2.1 days by aztreonam (2 x 1 g/24 h) administered by short infusion (30 min) for a severe infection due to a Gram-negative bacilli. The primary (n = 25) or nosocomial (n = 4) infection sites were a peritonitis (14), a septicaemia (6), a cholecystitis (6), a pyelonephritis (5), a cholangitis (2), a subphrenic abscess (1) or a pneumonia (2). The isolated Gram-negative bacilli were all susceptible to aztreonam, their MIC being less than or equal to 0.5 micrograms/ml, except for a Pseudomonas aeruginosa (MIC = 4 micrograms/ml). Aztreonam was administered as a single therapy to 7 patients and in association with metronidazole (18) and/or penicillin G (14) to 22 patients; in fact, anaerobes were isolated in ten patients. The mean serum concentrations of aztreonam, as measured by HPLC, before and after the 7th administration respectively were 83.2 +/- 17.5 and 6.1 +/- 5.5 micrograms/ml for peak and through levels. The treatment of the 29 infections was a success in all the cases. No complication occurred due to the presence of Gram positive cocci (n = 4) in the first bacteriological sample, or due to the emergence (n = 12) of Gram positive cocci, except for one case of sepsis of the abdominal wall by Staphylococcus aureus. Aztreonam (2 x 1 g/24 h) may be a suitable alternative for the treatment of severe infections of intensive care units, mostly due to Gram-negative bacilli.