The renal hemodynamic response following a meat meal in children with chronic renal failure and in healthy controls

The renal hemodynamic response to a meat meal (2 g/kg BW) was studied in 11 healthy children and in 10 children with a mean plasma creatinine concentration of 2.6 +/- 0.1 mg/dl due to chronic renal failure (CRF) of various etiologies. In the healthy status, after a meat meal, the glomerular filtration rate (GFR) increased significantly from a baseline value of 119.0 +/- 5.0 to a peak of 159 +/- 5.8 ml/min x 1.73 m2; in CRF baseline GFR averaged 49 +/- 4.0 and at peak 76.6 +/- 7.2 ml/min x 1.73 m2 (p less than 0.005). The peak GFR response was reached earlier in healthy subjects than in CRF (p less than 0.05) and did not correlate with age or with baseline GFR. Renal plasma flow (RPF) in healthy controls increased from 532 +/- 32 at baseline to 646 +/- 42.9 ml/min x 1.73 m2 after the meal (p less than 0.005). Also in CRF after a meat meal there was a significant increase in RPF from 278 +/- 51 to 65 +/- 66 ml/min x 1.73 m2 (p less than 0.005). The filtration fraction was not affected. The percent increase over baseline values of GFR and RPF at the peak was significantly higher in diseased children. Renal reserve averaged 28.1 +/- 5.3 ml/min in diseased children and 39.7 +/- 5.2 ml/min (p less than 0.01). The data indicate that (1) a meat meal is a suitable method to recruit renal reserve in normal children and in children with chronic renal failure, and (2) the renal reserve is normal in chronic renal failure.

Low protein alimentation normalizes renal haemodynamic response to acute protein ingestion in type 1 diabetic children

The effect of an acute protein load (2 g kg-1 bodyweight [BW]) was studied in nine type 1 diabetic children. Patients were maintained on two different dietary regimens. In study one, patients were on a high protein diet providing from 2.7 to 1.8 g of protein/kg of BW per day. In study two, patients were reevaluated after three weeks of a diet providing from 1.0 to 1.2 g kg-1 of BW per day of protein. In study one (High Protein Diet), we failed to observe any rise in GFR and RPF following the protein meal (137 +/- 21 basal vs. 110 +/- 14 and 472 +/- 93 basal vs. 494 +/- 93 ml/1.73 m2 of SA min-1 at 60 min. This is in contrast with results from seven age matched controls consuming a free diet, which showed a significant rise in both GFR and RPF. In study two (low protein diet), basal GFR was significantly reduced. However after the protein load, both GFR (92 +/- 11 vs. 126 +/- 18 ml/1.73 m2 of SA min-1) and RPF (467 +/- 83 vs. 705 +/- 102 ml/1.73 m2 min-1) rose significantly (P less than 0.05 vs. basal). The data indicate that: 1. short term protein restriction reduces significantly GFR in type 1 diabetic children; 2. diabetic children maintained on an high protein intake show an altered haemodynamic response to protein ingestion; 3. a normal response to protein ingestion can be restored by short term dietary protein restriction.

[Markers of viral replication (HBeAg and DNA polymerase activity) in chronic uremia, HBsAg positive, hemodialysis patients]

The contagiousness of hepatitis B virus (HBV) carriers with end-stage renal disease undergoing chronic hemodialysis has been ascribed to an immunologic tolerance for HBV antigens, especially hepatitis B core antigen, supporting persistently high levels of virus replication. In this context hepatitis B e antigen and core-associated DNA polymerase (DNA P) activity have proved to be distinct markers of HBV replication. In order to evaluate the potential infectivity of these subjects, thirty-five HBsAg positive hemodialysis patients were studied for the presence of HBeAg/anti-HBe system correlating the results with serum DNA P activity. Twenty out of 35 patients were HBeAg positive (57%) and 21 DNA P positive (60%). A highly significant correlation (P less than 0,001) was recorded between detection of HBeAg and presence of serum DNA P activity. These findings confirm that the majority of hemodialysis patients carrying HBsAg show high levels of virus replication so that the determination of HBeAg and DNA P activity other than HBsAg is required for the identification of patients highly infectious.

[Serologic diagnosis of acute hepatitis A. Refinement and evaluation of 3 methods of determining specific anti-HAV IgM]

A solid phase radioimmunoassay (RIA) procedure was developed and three methods for detection of IgM specific antibody to hepatitis A virus (anti-HAV IgM) were compared: triple antibody method, 2-MercaptoEthanol (2-ME) for IgM cleavage and Staphylococcal A Protein (StAP) for IgG absorption. Specificity and sensitivity of the tests were checked for evaluating acute and convalescent sera from 40 patients with serologically (seroconversion) diagnosed hepatitis A and 64 sera from patients with various acute viral diseases or with high titre of rheumatoid factor (RF). Specimens to be assayed for anti-HAV IgM were pretreated with 2-ME or StAP and tested by RIa using 125I labelled anti-HAV IgG. Triple antibody method showed to be more sensitive than other two methods giving false positive result in only one serum containing high levels of monoclonal RF. No significant difference in sensitivity and specificity was found between 2-ME and StAP procedure, but these methods were able to detect anti-HAV IgM for only two weeks after the onset of the disease, whereas triple antibody method gave positive results for at last seven weeks.

Cyclic-AMP content in Escherichia coli B/b as affected by N1-(delta 2-isopentyl)adenine

N6-(delta 2-isopentenyl)adenine, like other cytokinins, does not detectably modify Escherichia coli growth, but strongly affects cellular levels of cAMP. A substantial delay of the highest level of intracellular cAMP, a reduction to about one half of such maximum level, and a slight increase of cAMP secreted into the medium are reported.

Cytokinin ocntents and cAMP metabolism during growth of Escherchia coli

During Escherichia coli growth, we found an inverse correlation between free cytokinin content and cAMP level. The rates of synthesis of adenylate-cyclase and cAMP-phosphodiesterase were practically constant.