Plasma ionized magnesium levels in neonatal respiratory distress syndrome

Measurement of ionized magnesium (IMg) provides an accurate assessment of the free form of Mg, which is the physiologically active form and is most reflective of the biologically active and not easily measurable intracellular Mg fraction. Plasma levels of IMg were measured by ion-selective electrode method in premature newborns with respiratory distress syndrome (RDS), and relationships and correlations between IMg levels and various demographic, prognostic and laboratory characteristics were investigated by comparing the premature newborns with (study group; n = 19) and without RDS (control group; n = 20) in the present study. The values of the postnatal arterial pH and base excess and plasma IMg levels were significantly different between the study and control groups, and the number of newborns with any morbidity was significantly higher in the study group. Within the study group there were significant negative correlations between the plasma IMg levels and the values of the umbilical cord arterial pH (r = -0.621, p = 0.005) and base excess (r = -0.746, p = 0.001), and the value of the postnatal arterial base excess (r = -0.585, p = 0.008). The newborns who died later had higher plasma IMg levels than those who survived (0.89 +/- 0.45 vs. 0.63 +/- 0.24 mmol/l, p = 0.026). These findings suggest that increase of plasma IMg may be due to extracellular movement of Mg, which is a principally intracellular ion, as a result of acidosis, hypoxia and probable cellular injury during the early course of RDS. The exact pathophysiological mechanism responsible for IMg increase, and whether determination of plasma IMg level, including umbilical cord blood IMg measurement, can be used as an early or predictive indicator of RDS in the diagnosis remain to be determined in further large-scale studies.     

Seizures in the developing brain cause adverse long-term effects on spatial learning and anxiety

PURPOSE: Seizures in the developing brain cause less macroscopic structural damage than do seizures in adulthood, but accumulating evidence shows that seizures early in life can be associated with persistent behavioral and cognitive impairments. We previously showed that long-term spatial memory in the eight-arm radial-arm maze was impaired in rats that experienced a single episode of kainic acid (KA)-induced status epilepticus during early development (postnatal days (P) 1-14). Here we extend those findings by using a set of behavioral paradigms that are sensitive to additional aspects of learning and behavior. METHODS: On P1, P7, P14, or P24, rats underwent status epilepticus induced by intraperitoneal injections of age-specific doses of KA. In adulthood (P90-P100), the behavioral performance of these rats was compared with that of control rats that did not receive KA. A modified version of the radial-arm maze was used to assess short-term spatial memory; the Morris water maze was used to evaluate long-term spatial memory and retrieval; and the elevated plus maze was used to determine anxiety. RESULTS: Compared with controls, rats with KA seizures at each tested age had impaired short-term spatial memory in the radial-arm maze (longer latency to criterion and more reference errors), deficient long-term spatial learning and retrieval in the water maze (longer escape latencies and memory for platform location), and a greater degree of anxiety in the elevated plus maze (greater time spent in open arms). CONCLUSIONS: These findings provide additional support for the concept that seizures early in life may be followed by life-long impairment of certain cognitive and behavioral functions. These results may have clinical implications, favoring early and aggressive control of seizures during development.     

<Emphasis Type="Italic">CYP2C9</Emphasis> genetic variants and losartan oxidation in a Turkish population

Objective Cytochrome P₄₅₀ 2C9 (CYP2C9) is a polymorphic enzyme catalysing the metabolism of several important drugs. Losartan has recently been suggested as a selective probe for CYP2C9 metabolic activity. The aim of the study was to determine the activity of CYP2C9, using losartan as a probe drug, in relation to CYP2C9 genotype in healthy Turkish subjects.Methods A single oral dose of 25 mg losartan was given to 85 Turkish unrelated subjects. Concentrations of losartan and its carboxylic acid metabolite, E3174, were analysed by means of high-performance liquid chromatography in urine collected for 8 h. The CYP2C9 genotypes were determined in 85 subjects using polymerase chain reaction-based endonuclease digestion methods specific for CYP2C9*2 and *3. Losartan oxidation was also studied in vitro, using human CYP2C8 and CYP2C9 enzymes expressed in yeast.Results The frequencies of the allelic variants CYP2C9*2 and CYP2C9*3 were 0.100 and 0.088, respectively. The urinary losartan/E3174 ratio was significantly higher in subjects with CYP2C9*1/*3 genotype (median 2.35, n=12) than in subjects with CYP2C9*1/*1 (0.71, n=58) and *1/*2 (0.85, n=10) genotypes (P<0.05). In contrast to CYP2C9, no E3174 was formed by CYP2C8 in vitro.Conclusion The urinary losartan to E3174 metabolic ratio after a 25-mg losartan dose was found to be a safe and useful phenotyping assay for CYP2C9 activity in vivo. CYP2C9*3 variant allele is a major determinant of the enzyme activity, and it decreases losartan metabolism significantly, while CYP2C9*2 allele has less impact on enzyme function.     

Intestinal parasites in children with neoplasms

Stool specimens taken from 50 children with malignancy and from 92 healthy children were investigated for intestinal parasites, using the modified formol ethyl acetate concentration method, and native-lugol, trichrome and Kinyoun acid-fast stain methods. Thirty-eight (76.0%) of the 50 patients had lymphoma or leukemia and were considered immunosuppressed. Several different parasites were found in 21 (42.0%) of the 50 patients with malignancy and in 16 (47.3%) of the 38 patients with immune deficiency compared to in only 16 (17.3%) of the 92 healthy children. The incidence of parasites in patients with malignancy or immunosuppression was significantly higher than in the healthy control group (p<0.01, p<0.01).     

Evaluation of bone mineral density in children with cerebral palsy

In the present study, bone mineral density of 40 children with cerebral palsy (study group) and the effects of various risk factors on bone mineralization in these children were investigated by comparing with 40 age-matched healthy children (control group). Weight, height, skinfold thickness, body-mass index measurements, and serum levels of calcium, phosphorus, alkaline phosphatase and 25 OH vitamin D were not significantly different between the study and control groups (p>0.05). The mean bone mineral density value of the study group measured by dual-energy X-ray absorptiometry method at L2-L4 levels of lumbar vertebrae was significantly lower than that of the control group (p<0.05). When the patients in the study group were assessed with respect to ambulation status, pattern of involvement, calcium and energy intakes, and whether or not they had taken and/or were taking a regular physical therapy program, there was a significant difference only between the hemiplegic and tetraplegic patients (p<0.05), while there were no significant differences among the patients who were ambulant versus non-ambulant, who had sufficient versus insufficient calcium and energy intakes, and who did and did not take a regular physical therapy (p>0.05). Although the ambulatory status, quantity of calcium and energy intakes, and the presence or absence of a physical therapy program had no effects on bone mineral density values of the children with cerebral palsy in this study, the exact factors and mechanisms responsible for the reduced bone mineral density in children with cerebral palsy should be investigated in further large-scale studies considering the increased risk of pathological fractures in these patients.     

Estradiol suppresses vascular monocyte chemotactic protein-1 expression during early atherogenesis

OBJECTIVE: This study was undertaken to determine whether estrogen down-regulates vascular monocyte chemotactic protein-1 expression during the development of atherosclerosis in vivo and to identify the cellular localization of monocyte chemotactic protein-1 expression under baseline conditions and in response to atherogenic stimuli. STUDY DESIGN: Female, homozygous low-density lipoprotein-receptor-deficient mice (n = 68) in a C57BL/6 background underwent ovariectomy, were implanted subcutaneously with 17beta-estradiol or placebo pellets, and were changed to a high cholesterol (1.25%) diet. Thereafter, four mice from each group were killed weekly for 8 weeks, and their aortae were frozen for immunohistochemical analysis. The lipid deposition was identified by Sudan black B staining. Monocyte chemotactic protein-1 expression was detected with a rabbit anti-mice monocyte chemotactic protein-1 antibody, and semiquantitative analysis was performed. RESULTS: Consistent with previous reports, estradiol resulted in diminished vascular lipid deposition (22% +/- 7% vs 15% +/- 6% at 8 weeks of gestation, P <.05). We found that the inhibition of lipid deposition in aortae of animals that were treated with estrogen is associated with a concomitant down-regulation of monocyte chemotactic protein-1 immunoreactivity in aortic endothelial and smooth muscle cells (P <.05). Serum total cholesterol concentrations did not differ between the two treatment groups, which suggests a direct effect of estradiol on the aorta. CONCLUSION: Our findings suggest that one of the mechanisms by which estrogen down-regulates atherogenesis is by the suppression of vascular monocyte chemotactic protein-1 expression, which leads to decreased macrophage recruitment to the arterial wall early in the process.