Guido Cavalli

Single kidney function: Effect of acute protein and water loading on microalbuminuria

The hyperfiltration induced by an acute response to an oral protein and water load was investigated to ascertain whether it can modify the urinary albumin excretion (UAE) in the microalbuminuric range by further increasing the glomerular filter permeability. To this end, six patients with a single kidney selected as having microalbuminuria on a regular diet without the clinical or laboratory data of overt renal disease and eight healthy subjects received a short-term protein and water load (150 g of meat-derived protein and 1 liter of water). In patients with one kidney, mean basal UAE values were significantly higher than in control subjects (p less than 0.006), whereas endogenous creatinine clearance values were only slightly lower (p greater than 0.05). One hour after the protein and water load, an abrupt increase in microalbuminuria levels was found in patients with one kidney and mean UAE values were significantly higher than in control subjects (p less than 0.002), whereas mean creatinine clearance values were significantly lower in patients than in control subjects (p less than 0.01). High UAE (p less than 0.002) and low creatinine clearance (p less than 0.002) values were maintained over the following four hours in patients with one kidney. These data suggest that in the single kidney with reduced renal functional reserve, an oral protein and water load magnifies the pre-existing loss of glomerular permselective properties due to chronic hyperfiltration as manifested by a further increase in microalbuminuria.

Maternal predictors of HIV vertical transmission

We performed a retrospective study of 57 HIV-positive pregnant women and their children to look for maternal parameters related to rates of vertical transmission of HIV. Sixteen (28%) infants were HIV-infected. There was no positive correlation between maternal risk factors for HIV and vertical transmission of HIV. Multiparity seemed to be related to a higher prevalence of vertical transmission, whereas neither preterm delivery nor cesarean section resulted in different rates of vertical transmission, although they tended to have some protective effect. Maternal beta 2-microglobulin and serum neopterin levels were not related to different rates of vertical transmission of HIV. CD4+ cell counts did so only when cut-off values of 400/mm3 were taken. All the women in CDC group IV and all the HIV p24 antigen-positive transmitted the infection to their infants, whereas only 7/48 women in CDC groups II and III (P = 0.000006) and 9/48 HIV p24 antigen negative women (P = 0.00006) gave birth to infected infants. No other maternal characteristics were associated with different rates of vertical transmission in a multivariate analysis restricted to women in CDC groups II and III and with HIV p24 antigen negativity.

Soluble interleukin-2 receptors and beta 2-microglobulin in patients with primary glomerulonephritis.

Serum levels of soluble interleukin-2 receptors (IL2R) and of beta 2-microglobulin (beta 2M) were studied with the immunoenzymatic technique in 38 patients with primary glomerulonephritis (GN), in 10 patients with essential hypertension (EH) and in 30 healthy subjects. IL2R correlated with beta 2M (p < 0.05). IL2R and beta 2M were higher in patients with GN (p < 0.003, p < 0.001, respectively) and in patients with EH (p < 0.003, p < 0.01, respectively) than in healthy subjects. IL2R and beta 2M correlated with serum creatinine, but not with proteinuria. Our data would suggest the existence of lymphocyte activation in patients with GN. Only speculations can be advanced with regard to the observed increase in these parameters in EH patients.

Diagnostic and prognostic significance of β2-microglobulin during HIV infection

SummaryThe serum levels of β2-microglobulin (β2-m) were determined in 80 intravenous drug addicts (IVDA) with acquired immunodeficiency syndrome (AIDS), in 128 HIV-positive IVDA with persistent generalized lymphadenopathy (PGL) and in 44 HIV-seronegative IVDA. Seventy-two out of 80 (90%) AIDS patients had elevated serum β2-m levels and high levels of β2-m were also found in 105 of 128 (82%) HIV-infected subjects without AIDS. The mean β2-m level was significantly higher in HIV-infected patients with PGL than in HIV-negative IVDA. Nine out of 64 (14%) PGL patients developed AIDS in a period of 24–54 months. In these patients the mean β2-m level (5.16±2.37 mg/1), obtained from sera stored at the first observation, was significantly higher than in the other PGL patients (3.40±1.03 mg/l); in particular, 5 out of 7 PGL patients with β2-m levels >5.0 mg/l showed an advanced disease.