Güler Öztürk

Urinary Nitric Oxide in Newborns with Infections

Background: Neonatal sepsis is a major problem in newborn nurseries because of the difficulty in early diagnosis and because of the high morbidity and mortality. The objective of the present study was to investigate whether urinary nitric oxide (NO) levels could be useful for the diagnosis of infected newborns. Methods: Newborns with suspected infection according to previously defined criteria between ages of 1–7 days and 8–30 days were included as the study groups (p) to be compared with age-matched healthy controls (c). Urine NO levels were assayed by Sievers NOA based on chemiluminescence and expressed as corrected for urine creatinine. Results: 20 newborns with suspected infection at 1–7 days of age (group 1p) were compared with 45 healthy age-matched newborns (group 1c). 16 newborns with suspected infection at 8–30 days of age (group 2p) were compared with 15 healthy age-matched newborns (group 2c). The groups were similar with regard to birth weight and gestational age; however, the urinary NO levels in newborns with suspected infection at 1–7 days of age (80.25 ± 60.68 μmol/mg creatinine) were higher than in healthy newborns (25.45 ± 19.35 μmol/mg creatinine). Similarly, newborns with suspected infection at 8–30 days of age had higher urinary NO levels (81.78 ± 40.43 μmol/mg creatinine) than age-matched controls (36.99 ± 24.58 μmol/mg creatinine; p < 0.05). The sensitivity of urinary NO levels to detect infection was 50% in both age groups, and the specificity was 95% for 1–7 days of age and 93% for 8–30 days of age. Groups 1p and 2p were similar with regard to NO production. Altogether 12 patients had culture-proven sepsis, 11 patients had clinical sepsis, and 13 patients had other infections. The NO levels were similar in patients with culture-proven and clinical sepsis and higher than in patients with other infections. No difference was observed among NO levels of patients with gram-positive and gram-negative sepsis. Conclusions: Urinary NO levels which are quick and easy to measure are higher in infected newborns as compared with controls, and although the specificity is good, the sensitivity of the test is low, necessitating the use of another marker in addition to NO.

Decreased natural killer (NK) cell activity in zinc-deficient rats

1. In the study, the effect of zinc deficiency, a natural killer (NK), and lipopolysaccharide (LPS) activated NK cell activity were investigated. 2. Rats were fed with zinc-deficient and normal diet for 3 weeks. 3. NK and LPS activated NK cell activity was 7.2 +/- 1.8%/10(6) cells (n = 10) and 9.5 +/- 4.3%/10(6) cells (n = 10), respectively, in the zinc deficient group. In the control group fed with normal diet, NK and LPS activated NK cell activity was 22.2 +/- 3.3%/10(6) cells (n = 10) and 32.5 +/- 3.5%/10(6) cells (n = 10), respectively. 4. Plasma zinc concentration was 131.7 +/- 8.8 micrograms/dl in the zinc-deficient group and 206 +/- 17.7 micrograms/dl in the control group. 5. The results suggest that decreased NK and LPS activated NK cell activity is associated with zinc deficiency.

Natural killer cell activity, serum immunoglobulins, complement proteins, and zinc levels in patients with psoriasis vulgaris.

The role of the immune system in patients with psoriasis vulgaris (PV) was investigated. The genetic and immunological basis for psoriasis is still unknown. Because of the reports of immunological defects in this disease, we investigated serum levels of immunoglobulins IgG, IgM, IgA, complement proteins C3, C4, serum zinc (Zn) levels and natural killer (NK) cell activities. Skin lesions of the psoriatic patients involved in the study comprised less than 10 % of the total body and the disease was in a stationary period. Zn levels were measured by atomic absorption spectrophotometry. NK cell activity was measured by 51Cr (Na2 51CrO4). IgG, IgA, IgM, C3 and C4 assays were done by liquidphase immunoprecipitation assay with nephelometric endpoint detection. IgG, IgA, C3 and C4 levels were significanty higher in patients with PV than in healty controls (p < 0.05). However, NK cell activity, serum Zn and IgM levels did not show significant differences between these two groups. There are changed immunological responses, which may play an important role in the pathogenesis of the disease. Many controversial results have been related to immunological parameters in psoriatic patients. Therefore, more detailed studies in this field need to be done to determine the relationship between psoriasis and the immune system.

Cerebrospinal fluid levels of nitric oxide and nitrotyrosine in neonates with mild hypoxic-ischemic encephalopathy.

The objective of this study was to determine the role of cerebral nitric oxide and its powerful oxidant peroxynitrite following mild birth asphyxia. The cerebrospinal fluid levels of nitric oxide and 3-nitrotyrosine as a marker for peroxynitrite are measured in neonates with mild hypoxic-ischemic encephalopathy. Based on the classification of Sarnat and Sarnat, term neonates with mild hypoxic-ischemic encephalopathy and neurologically normal neonates suspected of sepsis were taken as the control group. Nitric oxide measurements were done by chemiluminescence, and nitrotyrosine measurements were made by high-performance liquid chromatography. The Mann Whitney U-test was used, and a P value < .05 was considered significant. Eleven patients with grade 1 hypoxic-ischemic encephalopathy and nine controls were included. The gestational age and birthweights were similar in both groups. Neither of the cerebrospinal fluid levels of nitric oxide (8.60 ± 0.49 μmol/L) and nitrotyrosine (0.45 ± 0.33 μmol/L) of the neonates with hypoxic-ischemic encephalopathy showed significant differences from that of the means of nitric oxide (8.66 ± 1.07 μmol/L) and nitrotyrosine levels (0.25 ± 0.13 μmol/L) of the controls. These data suggest that the oxidative stress is not overexpressed to lead nitric oxide and peroxynitrite to play a pathologic role in the early phase of mild hypoxic-ischemic encephalopathy of the newborn. (J Child Neurol 2002;17:815-818).

Biochemical alterations in neonatal hypoxic ischaemic brain damage

Asphyxiated (n = 39) and control (n = 23) were elected for the study. Free radical-mediated lipid peroxidation, prostaglandin E2 and vitamin E levels were studied and the degree of hypoxic ischaemic encephalopathy was determined in each case. In the hypoxic group the concentration of prostaglandin E2 activity (P < 0.05) and malondialdehyde levels (P < 0.01) were significantly higher when compared to that of controls. The high vitamin E concentrations in the asphyxiated infants supports the role of oxygen free radicals in hypoxic ischaemic encephalopathy of newborns.