Arylsulfatase-A in umbilical cord blood: gestational age and mode of delivery do not influence enzyme activity

The possibility of using umbilical cord blood for transplantation in several enzyme deficiencies has received increasing attention because of the availability of cord blood, the reduced incidence of post-transplantation complications, such as graft-versus-host disease and the possible accomplishment of good corrective results following transplantation, even in cases of greater HLA disparity. The use of hematopoietic stem cells from unrelated donors is even more highly recommended for the treatment of inherited enzyme deficiencies, because it might reduce the risk of the transplanted cells originating from a carrier of the defect, which might have an inadequate corrective ability. Our study was designed to elucidate whether the gestational age and mode of delivery influences the arylsulfatase-A activity in the umbilical cord blood. Enzyme activities proved to be similar in the four populations studied (full-term normal spontaneous vaginal delivery, full-term caesarean section, preterm normal spontaneous vaginal delivery and preterm caesarean section). Therefore, umbilical cord blood samples seem to be suitable for transplantation in metachromatic leukodystrophy, regardless of gestational age and mode of delivery. Moreover, our results are the first published data on normal values for arylsulfatase-A activity in human umbilical cord blood.

Natural killer cell cytotoxicity is deficient in newborns with sepsis and recurrent infections

We investigated natural killer (NK) cell cytotoxicity in healthy preterm and full-term newborns in comparison to adults, to elucidate the possible role of delivery mode in influencing the NK activity and to evaluate the NK activity in severe neonatal pathological conditions such as bacterial sepsis and recurrent infections. NK cell cytotoxicity was investigated using a 4 h 51Cr release assay with K562 cells as targets expressed as percentage kill in the following study groups: full-term normal spontaneous vaginal delivery (n = 55), full-term caesarean section (n = 51), preterm normal spontaneous vaginal delivery (n = 34), preterm caesarean section (n = 28), bacterial sepsis (n = 15), recurrent neonatal infections (n = 8) and healthy adults aged between 22-42 years (n = 89). NK activity for the normal newborns was determined in paired cord and 2-4 day-old neonate blood. The NK cell cytotoxicity in healthy newborns was significantly lower than in adults (P < 0.01). Prematurity was associated with a significant decrease in NK cell activity compared to full-term neonates (P < 0.05). The mode of delivery did not influence the NK cytotoxicity. In sepsis and recurrent infections, a dramatic decrease in NK cell cytotoxicity was seen related to healthy newborns (P < 0.01).

CONCLUSION

Natural killer cell cytotoxicity is deficient in both neonatal sepsis and recurrent infections.

Renal injury in perinatal hypoxia: ultrasonography and changes in renal function

We studied 12 hypoxaemic neonates (5 mature newborns, birth weight 2850-4200 g, gestational age 37-41 weeks; and 7 premature newborns, birth weight 770-1850 g, gestational age 27-34 weeks;) with repeated urine and blood chemistry on the 1st and 3rd days of life. Nephrosonographical examinations on the 1st, 3rd and 5-7th days of life were also performed. As controls, 12 healthy infants were examined (gestational age 36-42 weeks; birth weight 24504200 g). Hypoxic neonates had higher serum creatinine and blood urea nitrogen levels. Tubular markers also demonstrated renal tubular damage. Neonates in both hypoxic groups were hyperuricaemic and hyperuricosuric, and had higher urinary protein concentrations. All these infants exhibited an increased echogenicity of the renal cortex, and 11/12 showed the same finding in the medullary area. These findings disappeared within 1 week in all infants. Among the 12 healthy control infants, no cortical hyperechogenicity was found and only three of these infants displayed transient medullary renal hyperechogenicity.

CONCLUSION

Since the hypoxaemic infants demonstrated greatly increased urinary concentrations of uric acid and protein, we suggest that a temporary precipitation of these two agents may be responsible for the ultrasonographic findings. Circulatory redistribution might play a role in the phenomenon of cortical hyperechogenicity.

Fetal renal artery flow and renal echogenicity in the chronically hypoxic state

The object of this study was to investigate the fetal renal arterial blood flow in normal and hyperechogenic kidneys during the third trimester of gestation. The pregnancies screened were all chronically hypoxic. Depending on the etiology of the intrauterine chronic hypoxia, the cases were divided into two study groups. Group I comprised 120 pregnant women with pregnancy-associated hypertension and/or proteinuria. Group II consisted of 87 pregnancies with intrauterine growth retardation. Both study groups included pregnant women from the third trimester. Hyperechogenic renal medullae were detected in 15 out of 120 cases with pregnancy-associated hypertension and/or proteinuria, and in 22 fetuses of the 87 pregnancies involving intrauterine growth retardation. Fetal renal hyperechogenicity appears to be an indicator of fetal arterial circulatory depression, correlated with pathological changes in the resistance index for the fetal renal arteries. The fetal renal arterial blood flow resistance index was significantly lower in hyperechogenic cases. This may also be an in utero indication of subsequent intrauterine and neonatal complications, such as cesarean section because of fetal distress (43%), treatment in a neonatal intensive care unit (51%) or increased perinatal mortality (5.4%, as compared with 0.8-1.0% in the normal population). Detailed ultrasound and Doppler examinations of renal parenchyma and arteries appear to be useful methods in the prenatal diagnosis of reduced renal perfusion and of intrauterine hypoxia to detect possible pathological fetal conditions in utero.

Fetal renal hyperechogenicity in pathological pregnancies

A relationship was sought between renal hyperechogenicity and the hypoxic state of fetuses. 120 pathological pregnancies were examined between the 28th and 36th week. All of these women exhibited moderately increased levels of hepatic enzymes, 3 of them had a pathological kidney function, and 4 of them displayed hyperuricemia during the examination period. The echogenicity of the fetal kidneys was examined with Hitachi EUB-450 ultrasound equipment with a 3.5 MHz transducer. The kidney (creatinine, urea-N, uric acid, triglyceride, cholsterin) and liver (SGOT, SGPT, GGT, bilirubin) functions and plasma electrolytes (Na, K, Ca, Cl) of the mothers were also examined and blood was collected from the pulsating umbilical artery for determination of the same parameters. After delivery, the physical condition of the neonates was followed and their kidneys were examined with the same ultrasound equipment within the first 5 days. There was a significant correlation between a pathological neonatal clinical outcome and the frequency of fetal and hyperechogenicity (chi-square test with Yates correction, p < 0.01). The results demonstrate that fetuses exhibiting renal hyperechogenicity in pathological pregnancies require particularly careful obstetric control and neonatological consultation. It is important that hyperechogenic cases be admitted to a perinatal intensive care unit. Fetal renal hyperechogenicity is considered to be associated with an enhanced risk of an adverse perinatal outcome.

The possible role of uric acid in renal hyper-echogenicity in neonatal hypoxic acute shock

Sonographic examinations as well as blood and urine chemistry tests were carried out in 4 neonates (3 mature, 1 premature) with transient renal failure, who were suffering from the effects of neonatal asphyxia of varying etiology. The first ultrasound examinations of the kidneys were performed within 24 hours after the hypoxic event. Simultaneously, blood and urine tests for parameters of renal function and purine metabolites were also carried out. Transient insufficiency of renal function could be detected in all cases with hyper-uricemia and hyper-uricosuria with no hypercalciuria. Ultrasonographic examinations showed hyper-echogenicity of the renal pyramids in all of the cases and hyper-reflectivity of the renal cortex in cases 2 and 4. In 3 cases, hyper-echogenicity appeared within 24 hours and disappeared in a short time, while in case 3 it could be detected from day 4 until day 14. These findings demonstrate, that the neonatal kidney is very sensitive to hypoxia and that hypoxic renal failure is accompanied by hyper-echogenicity of the kidneys. Uric acid is a possible cause of the renal hyper-echogenicity.

Herpesnephropathy

Two cases of acute renal insufficiency occurred in association with episodes of severe encephalitis due to herpes simplex type I. The possibility was considered that the renal failure was due to viral infection of the kidneys, and animal experiments were carried out in an attempt to confirm this. Young New Zealand albino rabbits were infected i. v. with HSV type I; the virus antigen was detected in the kidney of 8 of 10 animals, and IgG was found on the GBM in 9 of 19 animals. Viruria was observed in 12 of the 29 infected animals, and electronmicroscopic examination confirmed the presence of immune complexes in the glomeruli.

Uric acid nephropathy in shocked rats after blocking of uricase activity with triazine compounds

Uricase was inhibited by oxonic acid in rats subjected to sublethal tourniquet shock. Uric acid levels in serum and renal tissue increased considerably in animals thus treated. Following uricase inhibition and shock the animals developed uric acid nephropathy, which was well discernible macroscopically and also proved by polarization microscopy. The results support the assumption that uric acid nephropathy might be an additional factor in the development of renal failure due to shock in man. The absence of uricase in man may account for the high susceptibility of the human to acute renal failure.