Comparing Cystatin C- and Creatinine-Estimated Glomerular Filtration Rates in Patients With Thoracic Versus Sacral Motor Levels of Spina Bifida.

OBJECTIVE: Patients with myelomeningocele-type spina bifida are at increased risk of developing kidney disease from neurogenic bladder. Differences between creatinine- and cystatin C-estimated glomerular filtration rates were examined in patients with thoracic versus sacral level myelomeningocele given presumed differences in muscle mass. DESIGN: A retrospective chart review (2005-2018) was performed on 57 adults with myelomeningocele [thoracic n = 44 (77%); sacral n = 13 (23%)]. Concurrently obtained creatinine and cystatin C levels were extracted and calculated creatinine- and cystatin C-estimated glomerular filtration rates were compared. RESULTS: Mean creatinine-estimated glomerular filtration rate was significantly higher for thoracic [140.8 ml/min (SD = 23.9)] versus sacral myelomeningocele [112.0 ml/min (SD = 22.6), P = 0.0003]. There was no difference in cystatin C-estimated glomerular filtration rate between sacral [116.6 ml/min (SD = 23.7)] and thoracic myelomeningocele [124.8 ml/min (SD = 17.9)]. The mean difference between creatinine- and cystatin C-estimated glomerular filtration rates in thoracic myelomeningocele [24.2 ml/min (SD = 16.3)] was significantly greater than in sacral myelomeningocele [-12.8 (SD = 15.7), P < 0.0001]. CONCLUSIONS: There was a significantly higher discrepancy between creatinine- and cystatin C-estimated glomerular filtration rates in thoracic versus sacral motor levels of myelomeningocele. These data suggest that creatinine-estimated glomerular filtration rate may overestimate kidney function in patients with thoracic myelomeningocele. Providers who manage patients with thoracic myelomeningocele should consider monitoring cystatin C to evaluate for underlying renal disease.

ABO and Rh Blood Groups and Risk of Myelomeningocele.

AIM: To investigate the relationship between the distribution of ABO or Rhesus (Rh) blood group antigens and the incidence of myelomeningocele. MATERIAL AND METHODS: A retrospective data was reviewed for all myelomeningocele patients operated at a tertiary academic hospital between years 2014 and 2019. Age, sex, delivery method, physical and neurological examination findings, and radiological findings alongside with blood type of each patient were recorded. The data of blood group distribution among the study patients was compared to the data of healthy individuals in the same region. RESULTS: Patients with group B and AB showed a higher chance of developing myelomeningocele. Rh-positive blood group was associated with high incidence of myelomeningocele (93.5%), whereas Rh-negative blood group showed least association (6.5%). Rh-positive blood group was also found to be more frequent in patients with myelomeningocele with hydrocephalus and Chiari malformation. CONCLUSION: The findings of this study show that ABO and Rh blood groups have an effect on the development of myelomeningocele under the influence of environmental or genetic factors.

The role of vitamin D replacement therapy in serum FGF23 concentration in children with myelomeningocele compared with healthy children - a preliminary study.

Background Fibroblast growth factor 23 (FGF23) is a recently discovered bone-derived regulator of vitamin D metabolism and phosphate homeostasis. It inhibits phosphate reabsorption and calcitriol production by the kidney. Myelomeningocele (MMC) remains the most severe form of neural tube defects involving serious locomotor disability, osteoporosis and pathologic fractures. We aimed to investigate the influence of vitamin D replacement therapy on serum FGF23 concentration in children with MMC and compare the results with healthy participants. Methods This prospective analysis was conducted on 16 children with MMC and 20 healthy children. Serum FGF23 levels were measured; for the studied group, before and after vitamin D replacement therapy with cholecalciferol (vitamin D3). The children's medical charts were analyzed to determine age, sex, anthropometric measurements, calcium and phosphate, cholecalciferol and renal function parameters. Results There were significant differences in vitamin D and FGF23 serum concentrations between the studied groups. The median vitamin D levels in the MMC group increased during replacement therapy (7 vs. 18.5 ng/mL, p = 0.29) in comparison to the median of 25.5 ng/mL in the control group. In MMC children we found a significant decrease in median serum FGF23 after vitamin D replacement therapy (from 42.1 to 0 RU/mL, p < 0.001). FGF23 correlated positively with albumin, serum and urine phosphate levels and negatively with alkaline phosphatase. Conclusions 1. Serum concentration of FGF-23 is increased in MMC children in comparison to a healthy control group. 2. Vitamin D replacement therapy decreases FGF23 concentrations in MMC children, although further studies are still warranted to gain detailed insight on the FGF23 in the MMC population. 3. Children with MMC present vitamin D deficiency. Nutrition supplemented with low doses of cholecalciferol (vitamin D3) (intakes reaching recommended daily allowances) was insufficient to correct 25(OH)-D level in that population of patients.

Fetal blood-gas values during fetoscopic myelomeningocele repair performed under carbon dioxide insufflation.

Fetoscopic myelomeningocele (MMC) repair is performed using intrauterine carbon dioxide (CO2 ) insufflation. Sheep experiments have shown that CO2 insufflation is associated with significant fetal acidemia; however, corresponding data for human pregnancy are not available. We performed umbilical venous cord blood sampling in three patients during fetoscopic MMC repair at 25 + 1, 25 + 3 and 24 + 0 weeks' gestation, respectively. Fetal venous pH at the beginning of CO2 insufflation was 7.36, 7.46 and 7.37, respectively in the three fetuses, and repeat values were 7.28, 7.35 and 7.36 after 181, 159 and 149 min, respectively. The partial pressure of oxygen and CO2 was maintained in the normal range during these times, and pH decrease was less in Patient 3 who received humidified CO2 insufflation. Our observations suggest that, in contrast to sheep experiments, CO2 insufflation during fetoscopic myelomeningocele repair does not cause acidemia in human fetuses. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Associations between post translational histone modifications, myelomeningocele risk, environmental arsenic exposure, and folate deficiency among participants in a case control study in Bangladesh.

Arsenic exposure may contribute to disease risk in humans through alterations in the epigenome. Previous studies reported that arsenic exposure is associated with changes in plasma histone concentrations. Posttranslational histone modifications have been found to differ between the brain tissue of human embryos with neural tube defects and that of controls. Our objectives were to investigate the relationships between plasma histone 3 levels, history of having an infant with myelomeningocele, biomarkers of arsenic exposure, and maternal folate deficiency. These studies took place in Bangladesh, a country with high environmental arsenic exposure through contaminated drinking water. We performed ELISA assays to investigate plasma concentration of total histone 3 (H3) and the histone modification H3K27me3. The plasma samples were collected from 85 adult women as part of a case-control study of arsenic and myelomeningocele risk in Bangladesh. We found significant associations between plasma %H3K27me3 levels and risk of myelomeningocele (P<0.05). Mothers with higher %H3K27me3 in their plasma had lower risk of having an infant with myelomeningocele (odds ratio: 0.91, 95% confidence interval: 0.84, 0.98). We also found that arsenic exposure, as estimated by arsenic concentration in toenails, was associated with lower total H3 concentrations in plasma, but only among women with folate deficiency (ß = -9.99, standard error = 3.91, P=0.02). Our results suggest that %H3K27me3 in maternal plasma differs between mothers of infants with myelomeningocele and mothers of infants without myelomeningocele, and may be a marker for myelomeningocele risk. Women with folate deficiency may be more susceptible to the epigenetic effects of environmental arsenic exposure.

Cystatin C-calculated Glomerular Filtration Rate-A Marker of Early Renal Dysfunction in Patients With Neuropathic Bladder.

OBJECTIVE: To asses if cystatin c-calculated glomerular filtration rate (GFR) can reveal chronic kidney disease (CKD) not detected by creatinine-based calculations in a larger prospective cohort of children with myelomeningocele (MMC). Wheelchair-bound MMC patients frequently have low muscle mass, and assessing renal deterioration based on creatinine-based GFR is imprecise. MMC patients are also at risk for end-stage renal disease. METHODS: Prospectively enrolled patients with MMC underwent annual serum creatinine and cystatin c testing. Anthropometric measurements were obtained from clinic visit. The modified (bedside) Schwartz formula for creatinine-based GFR and the Zappitelli cystatin C formula were utilized for calculation. The exclusion criteria were patients with reduced GFR (CKD stage 2) or chronic CKD (CKD stage 3 and greater); these patients were excluded from analysis on the premise that they had already been identified for closer renal monitoring. RESULTS: A total of 131 patients were included in the analysis. The median creatinine-based estimated GFR was 126.5 mL/min/1.73 m2 (range: 22-310). The median cystatin C-based estimated rate was 98.5 mL/min/1.73 m2 (range: 16-171), yielding an absolute median rate reduction of 30.2%. Using cystatin c-calculated GFR, CKD stage was upgraded from stage 1 to ≥2 in 34 patients (26%). CONCLUSION: In MMC patients with poor muscle mass, cystatin C-based GFR is more sensitive than creatinine-based GFR in detecting early CKD. In this high-risk population, serial cystatin C estimation is a valuable tool in identifying children who may benefit from early nephrology referral and intervention.

Fasting serum blood measures of bone and lipid metabolism in children with myelomeningocele for early detection of cardiovascular and bone fragility risk factors.

OBJECTIVE: This study examined serum levels in children with myelomeningocele to identify the prevalence of pre-clinical signs of disease. DESIGN: A prospective, cross-sectional study. SETTING: Patients were actively recruited from multidisciplinary care clinics at tertiary children's hospitals from 2010-2012. The control comparison group was recruited by word-of-mouth. PATIENTS: Twenty-eight children with myelomeningocele (93% Hispanic; 17 males; 10.0 ± 2.1 years) and 58 controls (84% Hispanic; 30 males; 10.4 ± 2.4 years) provided ≥ 8-hour fasting blood samples with concomitant dual-energy x-ray absorptiometry measurements of body fat. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The serum analysis included a lipid panel (cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein), insulin, glucose, leptin, aspartate aminotransferase, alanine transaminase, alkaline phosphatase, albumin, creatinine, calcium, phosphatase, parathyroid hormone, and vitamin D. RESULTS: Children with myelomeningocele had higher body fat (35.2% versus 29.9%, p=0.01) and altered lipid profiles (lower high-density lipoprotein levels, 43.9 mg/dL versus 51.6 mg/dL, P = 0.03) suggesting elevated risk of metabolic syndrome. They also had a higher prevalence of vitamin D deficiency (43% versus 17%, p=0.02) and significantly lower levels of calcium (9.4 mg/dL versus 9.7 mg/dL, P = 0.003) and alkaline phosphatase (187.0 U/L versus 237.0 U/L, P = 0.003). Unexpectedly children with myelomeningocele had lower parathyroid hormone levels (14.5 pg/mL versus 18.4 pg/mL, P = 0.02) than controls despite lower calcium, vitamin D and alkaline phosphatase levels. This suggests an alteration in the sensing mechanism or response of the parathyroid gland to normal physiological stimuli in patients with myelomeningocele. CONCLUSIONS: Children with myelomeningocele have abnormal biochemical markers for cardiovascular disease, insulin resistance and bone and mineral metabolism. Early recognition and monitoring of these risk factors in patients with myelomeningocele may help prevent later complications.

Differential Diagnostics of Neoplastic and Inflammatory Processes in the Brain by Modifications NMDA Receptor Activity in Blood Cells with Verapamil and Ketamine.

For the development of methods of additional differential diagnostics of gliomas of various grades of malignancy and gliomas and local inflammatory processes in the CNS we studied the intensity of aggregation of peripheral blood cells under the influence of channel blockers ketamine and verapamil. In in vitro experiments, verapamil and ketamine in various dilutions (from 10 to 100,000 times) were added to blood samples and the effects of these dilutions on the intensity of blood aggregation in patients with gliomas of different degree of malignancy, traumatic brain injuries, and other types of neurosurgical pathologies were studied. A correlation was revealed between the decrease in surface charge of blood cells and the type of neurosurgical pathology. The use of functional properties of potential-dependent inotropic NMDA receptors and calcium channels allowed indirect estimation of their activity via parameters of blood cell aggregation induced by channel blockers ketamine and verapamil.

Bone mineral density in pediatric patients with meningomyelocele.

PURPOSE: The aim of this study was to determine the bone mineral density (BMD) and the factors leading to reduction in BMD in children diagnosed with meningomyelocele. METHODS: A total of 31 patients with meningomyelocele (mean (SD) age, 8.5 (3.9) years; 51.6%were females) and 22 healthy children were included. BMD of femoral neck and spinal L1­ L4 levels and markers for bone metabolism were recorded. RESULTS: BMD of femoral neck (p=0.001) and spinal L1­L4 (p = 0.01), serum calcium (p = 0.031), and urinary deoxypyridinoline (p=0.015) levels were significantly lower in patients than in controls. Mobilization was significantly reduced in lumbar (p=0.001) and thoracic (p=0.002) level meningomyelocele compared to controls, while a significant positive correlation was noted between BMD of spinal L1­L4 and mobility (r=0.58, p=0.015). CONCLUSIONS: Our findings suggest a decrease in BMD in meningomyelocele patients being associated with osteoporosis rather than nutritional and hormonal factors and the negative impact of higher levels of lesion on the mobility.

Serum 25-hydroxyvitamin D, osteocalcin, and parathormone status in children with meningomyelocele.

Sufficient vitamin D levels are required for normal skeletal development and mineralization. This is particularly important in children with meningomyelocele who are at an increased risk of osteoporosis. The purpose of this study was to assess serum 25-hydroxyvitamin D [25(OH)D] and the biochemical markers of bone metabolism (parathormone, osteocalcin, alkaline phosphatase, and electrolytes) in children with meningomyelocele. The patient group comprised 33 children with meningomyelocele. The mean 25(OH)D was 11.51 ± 7.87 ng/mL. A total of 97% of the subjects had a 25(OH)D level in the insufficient range (< 30 ng/mL) and 48.5% had a 25(OH)D level less than 10 ng/mL. Almost all patients had serum osteocalcin and phosphorus concentrations above the normal limits. The level of 25(OH)D negatively correlated with age and body weight. There were no correlations between the biochemical markers of bone metabolism and the ambulatory status. A significant correlation between serum 25(OH)D and osteoporosis was found.

Reference interval for serum creatinine in children and adolescents with myelomeningocele.

OBJECTIVE: In children and adolescents with myelomeningocele (MMC), the relation between muscle mass and body composition varies considerably, making it difficult to evaluate the relevance of renal function assessments done with serum (s)-creatinine. Therefore, a reference interval for enzymic s-creatinine in individuals with MMC was constructed. MATERIAL AND METHODS: Patients with MMC aged 1.5-18 years who consistently had chromium-51-labelled edetic acid clearance within normal limits (88-132 ml/min/1.73 m(2)) were selected for the study. Included were 52 girls and 71 boys with a total of 471 s-creatinine determinations. Children with normal body composition were used as controls. RESULTS: The mean s-creatinine concentration at the age of 1.5 years was 22 micromol/l in girls and 21 micromol/l in boys and increased to 38 micromol/l in girls and 58 micromol/l in boys at the age of 18 years. There was no difference between the genders until the age of 12. From the age of 3 years, there was a significantly lower median s-creatinine concentration in the MMC children compared with a healthy age-matched population. The median concentration of the MMC children was equivalent to the 2.5 percentile of the control group. CONCLUSION: From the age of 3 years, the reference interval for children and adolescents with MMC showed a lower median concentration for enzymic s-creatinine and a greater interindividual variation compared with the healthy age-matched population.

Presentation and evolution of organic central precocious puberty according to the type of CNS lesion.

OBJECTIVE: To evaluate the influence of the type and treatment of CNS lesion causing central precocious puberty (CPP) on the presentation, hypothalamic-pituitary function and final height. PATIENTS: One hundred patients with CPP caused by central nervous system (CNS) lesion. RESULTS: The CPP was the presenting symptom of the lesion in 25 (10 boys) and occurred in 75 patients (23 boys) previously treated for lesions. These were optic glioma or astrocytoma (n = 45), hydrocephalus (n = 22), hypothalamic hamartoma (n = 15), suprasellar arachnoid cyst (n = 10) and others (n = 8). The percentages of patients with increased height, bone age advance, testicular volume, LH/FSH peaks ratio after gonadotrophin-releasing hormone (GnRH) test and plasma testosterone concentration in boys and oestradiol in girls varied from one aetiology to another. The boys with hamartoma were significantly taller and had greater bone age advance, LH peak and testosterone than boys with optic glioma. The girls with hamartoma and suprasellar arachnoid cyst were significantly younger and had greater LH peak than girls in the other groups. All patients treated for optic glioma had hypothalamic-pituitary deficiencies, including GH (100%), thyrotrophin (71.4%), corticotrophin (12.5%) and pubertal (34.3%) deficiencies. Sixty percent of those with suprasellar cysts lacked GH. Final height was below -2 SD in 15/59 (25%) patients, including 5/11 not treated with GnRH analogue, 3/5 not treated with GH despite GH deficiency, and 2 with hydrocephalus as a result of meningomyelocele. CONCLUSIONS: The type of CNS lesion influences the presentation of CPP. This is probably caused by differences in the mechanisms inducing puberty and to the hypothalamic-pituitary deficiencies associated with the CPP as a result of a lesion and/or its treatment.

Homocysteine, folate, lipid profile and MTHFR genotype and disability in children with myelomeningocele.

STUDY DESIGN: We performed a cross-sectional study in myelomeningocele children. OBJECTIVE: To investigate plasma total homocysteine, folate, lipid profile, 5,10- metylenetetrahydrofolate reductase genotype (MTHFR) and disability. MATERIALS AND METHODS: Sixty patients aged between 2 and 14 years with myelomeningocele (18 ambulatory and 42 non-ambulatory) and 150 healthy children of same age, are investigated for lipid profile, homocysteine concentration and for the determination of MTHFR genotype. RESULTS: Plasma homocysteine concentrations were significantly higher in myelomeningocele children than in the control group. In myelomeningocele female group, there were higher levels of total cholesterol and very-low-density lipoprotein cholesterol with respect to the control group. Myelomeningocele children walking with tutorial aid showed triglyceride levels significantly lower than those observed in myelomeningocele non-walking children. CONCLUSION: Disability, insulin uptake, lipid, homocysteine, hormones plasma levels, and genetic factors such as allelic variants of MTHFR are possible for cardiovascular disease in myelomeningocele children. This study highlights the importance of a continuous surveillance of any changes in the lipid profile that should be corrected as soon as possible. Constant physical activity necessary to increase HDL levels should be planned in all susceptible children. Nonetheless, further investigations are necessary to identify new homocysteine susceptible genes for prevention of early atherosclerosis and consequent cardiovascular disease.

Tap-water enema for children with myelomeningocele and neurogenic bowel dysfunction.

AIM: To evaluate the outcome of transrectal irrigation (TRI) using clean tap water without salt in children with myelomeningocele and neurogenic bowel problems. METHODS: 40 children (21 boys and 19 girls; aged 10 mo to 11 y) with myelomeningocele and neurogenic bowel dysfunction were treated with TRI given by a stoma cone irrigation set daily or every second day. A questionnaire on the effects on faecal incontinence, constipation and self-management was completed by the parents, 4 mo-8 y (median 1.5 y) after start. Effects on rectal volume, anal sphincter pressure and plasma sodium were evaluated before and after the start of irrigation. RESULTS: At follow-up, 35 children remained on TRI, four had received appendicostomy, while one defecated normally. For all children but five (35/40; 85%) the procedure worked satisfactorily, but a majority found the procedure very time consuming and only one child was able to perform it independently. All children were free of constipation; most (35/40) were also anal continent. Rectal volume and anal sphincter pressure improved, while plasma sodium values remained within the normal range. CONCLUSION: Transrectal irrigation with tap water is a safe method to resolve constipation and faecal incontinence in children with myelomeningocele and neurogenic bowel dysfunction, but it does not help children to independence at the toilet.

Plasma antidiuretic hormone levels in children with spina bifida.

PURPOSE: Urological management of spina bifida patients is controversial. The goals of therapy of neurogenic bladder are continence, prevention of infections and preservation of urinary tract. Desmopressin has been recently used in a spina bifida population that is dry during the day (daytime continence was achieved with clean intermittent catheterization and anticholinergics) but wet at night. The aim of this study was to assess plasma antidiuretic hormone (ADH) levels in these children. MATERIALS AND METHODS: The study included 24 patients, 11 males and 13 females (mean age 6.4 years) referred to the Spina Bifida Centre of the Catholic University of Rome, and 57 normal age-matched controls. Morning (07.30-08.00 h) plasma ADH levels were measured using a specific radioimmunoassay. RESULTS: Plasma ADH levels (normal range 5-11 microg/l) did not differ between spina bifida population and healthy controls. Serum ADH had a mean of 6.8 microg/l in affected children and a mean of 7.4 microg/l in the controls. CONCLUSION: We conclude that the use of desmopressin in children with spina bifida should be reserved only in patients with decreased secretion of ADH, or may be useful in patients with persistent nocturnal incontinence to reduce night wetting. Therefore, research with a larger population is needed.

A cross-sectional study of dehydroepiandrosterone sulfate in prepubertal children with myelomeningocele.

OBJECTIVE: To assess biochemical characteristics of adrenarche in patients with myelomeningocele (MMC), we examined serum levels of dehydroepiandrosterone sulfate (DHEAS) in prepubertal MMC patients. PATIENTS AND METHODS: The study included a total of 54 prepubertal patients with MMC and shunted hydrocephalus: 13 patients (2 m, 11 f; aged 4.6-10.1 years, mean 8.1 +/- 0.4) with isolated pubarche (Tanner stage PH 2-4, B1 or testes volume < or =3 ml) and 41 prepubertal MMC patients without pubarche (17 m, 24 f; aged 2.0-11.9 years; mean 6.8 +/- 2.5). DHEAS levels were measured directly by chemiluminescence immunoassay (Nichols, USA). Auxological data (supine length, body mass index (BMI), arm span) and bone age (BA) were recorded. RESULTS: (mean +/- SD): Basal DHEAS levels correlated with chronological age (CA) (r = 0.32, p < 0.05), BA (r = 0.65, p < 0.01; n = 23), BMI (r = 0.54, p < 0.01) and pubic hair stage (PH1 vs. PH2-4, r = 0.49, p < 0.01). 10/11 patients aged 2-4 years had DHEAS levels in the normal range, whereas 18/40 (45.0%) of the 5- to 9-year-old patients showed elevated levels (>+2 SDS). Ten patients with isolated pubarche (10/13; 2 m, 8 f; CA 8.3 +/- 1.5 years) and 9 patients without pubarche (9/41; 6 m, 3 f; CA 6.9 +/- 2.1 years) had elevated DHEAS levels (+6.34 and +4.05 SDS, respectively). The values correlated with BA/CA ratio (p < 0.05, n = 23). There was a trend to higher BMI SDS levels in patients with elevated DHEAS levels. CONCLUSION: Our data show an early and increased activation of adrenal androgen secretion in MMC patients.

The effect of C677T mutation of methylene tetrahydrofolate reductase gene and plasma folate level on hyperhomocysteinemia in patients with meningomyelocele.

To evaluate the relationship between genotypes of methylene tetrahydrofolate reductase (MTHFR), and plasma folate and homocysteine (Hcy) levels in meningomyelocele, 21 Korean patients, 47 of their family members, and 43 healthy controls were recruited. The presence of C677T mutation in the MTHFR gene and plasma concentrations of folate/Hcy were investigated. The genotype frequency of C677T mutation was not higher in study groups (patients and family members). The plasma folate concentration showed no difference either between the study and the control groups or among MTHFR-genotypic groups. The plasma Hcy concentration in homozygotes in the study group was higher than that in the control group, and higher than that in heterozygotes when plasma folate levels were low (P=0.006). Although neither MTHFR genotype nor plasma folate/Hcy level plays a definite part on its own, they seem to have an additive effect on the occurrence of meningomyelocele. Our results support folate supplementation for the prevention of hyperhomocysteinemia and meningomyelocele.

Cell cycle properties in lymphocytes from children with myelomeningocele.

Children with spina bifida display a constellation of clinical features which include growth retardation, latex allergies, and recurrent infections. Clinical and epidemiological findings support the view that principle components of this congenital syndrome originate in an inherent susceptibility, and not necessarily as a secondary complication of the early central nervous system malformation. Critical requirements for normal neurulation include folic acid and a fully functional methylation cycle, both of which also promote cell proliferation. This suggests that elements of susceptibility may emerge as cells from an individual with myelomeningocele are induced to synthesize DNA and divide. As an in vitro correlate of proliferative activity, we compared cell cycle properties of peripheral blood lymphocytes (PBL) from children with spina bifida to those in age-matched healthy controls. The four patients selected for study all have typical lumbar level myelomeningocele with the Chiari II malformation as well as clinical features which we commonly observe. We exposed PBL to phytohemagglutinin in the presence of the thymidine analog bromodeoxyuridine. Using bivariate flow cytometric analysis of Hoechst 33258- and ethidium bromide-induced fluorescence, we measured percentages of cells which responded to the mitogen, and relative rates at which case and control cells traversed the first three cell cycles. In three of the four experiments a greater percentage of PBL from the patient than from the control responded to mitogen. Cells from these children also appeared to progress more rapidly into second and third cell cycles. In the fourth patient, an unusually high percentage of cells failed to respond to mitogen and the remainder progressed more slowly into later cycles. The biological functions of folic acid and methionine led us to expect that in the cells from children with spina bifida, DNA synthesis would be retarded, S phase prolonged and transitions between cycles delayed. These preliminary results contrast with original expectations for fractions of mitogen-responsive cells and rates of traversal. Further experiments with PBL and other cell types will be required to confirm the differences we observed and establish their biological significance. An association between abnormal proliferative capacity and NTD, whether positive or negative, will create a biological and experimental context in which to define metabolic factors in this condition.

Plasma homocysteine and methionine concentrations in children with neural tube defects.

Mild to moderate homocysteinemia in women has been associated with an increased frequency of pregnancies with neural tube defects (NTD). Homocysteinemia is also an independent risk factor for premature vascular disease. In addition to folic acid, supplemental Vitamin B12, Vitamin B6 and betaine may normalize homocysteine metabolism, decrease the risk for NTD formation, and correct related metabolic imbalances in children with NTD. By means of automated amino acid analysis, we assessed total non-fasting homocysteine and methionine in plasma from 24 children with myelomeningocele. This study group (mean age 10.5 +/- 4.9 years) included 12 girls and 12 boys randomly selected from our Birth Defects Clinic. Homocysteine concentrations in our patients (4.7 +/- 1.8 mumol/L) did not differ from those of 20 randomly selected child controls (5.1 +/- 2.6 mumol/L). The mean homocysteine concentration for 36 adult controls (9.3 +/- 3.0 mumol/L) was significantly higher than the mean for either group of children (p < 0.0001). Linear regression analysis revealed negative correlation of total plasma homocysteine with serum folate (r = -0.53; p = 0.01), but not of homocysteine with either methionine or B12. Plasma methionine concentrations from our patients did not differ from adult reference values. Elevated homocysteine in some mothers of children with NTD has been attributed to defective methylation of homocysteine. These preliminary results do not indicate such a defect in the children themselves. A more comprehensive study of homocysteine, methionine and related metabolites in children with NTD and age-matched controls will be required to determine the clinical significance of these findings.

Erythrocyte antioxidant enzyme activities in children with myelomeningocele.

Erythrocyte free radical scavenging enzyme activities and their cofactor trace elements in plasma were assessed in 26 selected patients with myelomeningocele, both parents from 10 selected families, and 14 healthy adult controls. All index children except one were deficient in erythrocyte glutathione peroxidase (GSH-Px). Nine of 10 parent pairs had at least one parent with deficient GSH-Px activity. Children with myelomeningocele had significantly lower GSH-Px activities than their parents; the group of 10 parent pairs had significantly lower GSH-Px activities than the control group; and glutathione reductase activities were significantly lower in parents and children with myelomeningocele compared with controls. A deficiency in one or more antioxidant enzymes may increase the risk for neural tube defects.