Plasma homocysteine levels and folate status in children with sickle cell anemia.

PURPOSE: A sensitive inverse relationship between plasma homocysteine concentration and folate status has been demonstrated. Although children with sickle cell anemia (SCA) are at potential risk for folate deficiency, plasma homocysteine levels have not been reported in such patients. Therefore, a study was designed to assess plasma homocysteine levels as a marker of folate status. DESIGN: Plasma homocysteine concentrations were measured in 120 children with SCA (102 in steady state and 18 during an acute complication) who had never received supplemental folic acid. Folate status was directly assessed in 34 of these patients. RESULTS: Plasma homocysteine levels in the patients with SCA and control subjects were similar. The mean value +/- 1 SD was 5.8+/-2.5 micromol/L (range, 1.6 to 14.1 micromol/L) in the patients with SCA and 6.1+/-2.7 micromol/L (range, 1.7 to 15.3 micromol/L) in 73 pediatric control subjects. In a subpopulation of the study group (34 children), simultaneous serum folate, red cell folate, and total homocysteine concentrations were also measured. Their serum folate and red cell folate concentrations were normal: 12.4+/-10.0 nmol/L (range, 1 to 42 nmol/L) and 604+/-374.7 nmol/L (range, 205 to 1741 nmol/L), respectively. There was no correlation of plasma homocysteine concentration with various clinical or laboratory measures or with red cell folate concentration. CONCLUSION: Folate stores in children with SCA not receiving folic acid supplements are adequate despite an underlying hemolytic anemia.     

Effect of feeding type on the efficacy of phototherapy

OBJECTIVE: The objective of this study was to assess the efficacy of phototherapy for nonhemolytic hyperbilirubinemia and rebound bilirubin levels in breast-fed newborns as compared with mixed-fed (breast milk and formula) newborns. STUDY DESIGN/SETTING: Prospective study of effects of feeding type on response to phototherapy in newborns. METHODS: The subjects were 53 full-term healthy newborns with nonhemolytic hyperbilirubinemia [defined as total serum bilirubin 12 mg/dL (205.2 micromol/L) in the first 48 hours of life or 15 mg/dl (256.5 micromol/L), on subsequent days]. Groups were formed according to type of feeding. Group 1 consisted of 28 breast-fed newborns and group 2 consisted of 25 mixed-fed newborns. Phototherapy was terminated when total serum bilirubin concentration fell to 14 mg/dL (< 239.4 micromol/L). Rebound bilirubin measurements were obtained 24 hours after phototherapy ended. RESULTS: The groups were comparable with respect to age at the start of phototherapy. The amount of weight loss (relative to birth weight) recorded at the start of phototherapy was significantly greater in group 1 than in group 2 (8.1+/- 3.9% vs. 5.4+/- 2.6% p = 0.004). The duration of phototherapy was significantly longer in group 1 than in group 2 (38.6+/- 12.6 h vs. 26.8+/- 9.4 h; P < 0.001). The 24-hour rate of decrease in bilirubin concentration in group 2 was significantly higher than that in group 1 [5.4+/- 2.2 mg/dL/d (92.3+/-37.6 micromol/L/d) vs. 4+/- 1.3 mg/dL/d (68.4+/- 22.2 micromol/L/d); p = 0.01]. The overall rate of decrease in bilirubin concentration in group 1 was significantly lower than that in group 2 [0.16+/- 0.05 mg/dL/h (2.73+/- 0.85 micromol/L/h) vs. 0.22+/- 0.09 mg/dL/h (3.76+/- 1.53 micromol/L/h); p = 0.01]. There was no significant difference between the two groups with respect to rebound bilirubin concentration (P = 0.184). Conclusion: Phototherapy effectively reduced bilirubin levels in breastfed newborns with hyperbilirubinemia, but these patients show significantly slower response to this treatment than mixed-fed newborns.     

Serum homocysteine and lipoprotein (a) concentrations in hypercholesterolemic and normocholesterolemic children

The relationship between lipids, lipoproteins, total homocysteine, and lipoprotein (a) was studied in hypercholesterolemic and normocholesterolemic children. In hypercholesterolemic children, concentrations of total cholesterol, low-density lipoprotein (LDL) cholesterol, apolipoprotein B, and triglycerides were significantly higher compared to levels in controls, whereas concentrations of high-density lipoprotein (HDL) cholesterol and apolipoprotein A-I were lower compared to those in the control group. Total serum homocysteine concentrations in children with a positive family history for cardiovascular disease CHD(+) (7.28 micromol/L) were significantly higher than those in the control group (5.45 micromol/L), and in the group of CHD(-) children (5.25 micromol/L). The median value of lipoprotein (a) in patients was 31.5 mg/dL (range, 11-209 mg/dL) and in the control group, 19 mg/dL (range, 11-95 mg/dL). Concentrations of Lp (a), exceeding 30 mg/dL, were present in 45% of CHD(+) children, in 29% of CHD(-) children, and in only 11% of the control group.     

Homocysteine levels during fasting and after methionine loading in adolescents with diabetic retinopathy and nephropathy

OBJECTIVE: To assess plasma homocysteine levels in adolescents and young adults with type 1 (insulin-dependent) diabetes with and without microvascular complications. STUDY DESIGN: Homocysteine levels were measured during fasting and after methionine loading in plasma of 61 patients with onset of diabetes before the age of 12 years and duration of disease longer than 7 years. They had an albumin excretion rate (AER) between 20 and 200 microg/min in 2 of 3 overnight urine collections in a period of 6 months and/or retinopathy. Patients with persistent microalbuminuria were divided into 2 groups: subjects with AER of 20 to 70 microg/min and patients with AER of 70 to 200 microg/min. Adolescents (n = 54) without signs of diabetic retinopathy or nephropathy and matched control subjects (n = 63) were also studied. RESULTS: Homocysteine concentrations before and after methionine load were higher in adolescents with diabetic complications than in healthy subjects (fasting values: 12. 4 +/- 7.9 micromol/L vs 7.8 +/- 4.2 micromol/L; P <.01; after methionine load: 28.1 +/- 13.2 micromol/L vs 16.6 +/- 7.3 micromol/L; P <.005). Values of 11.9 micromol/L or higher were considered to constitute fasting hyperhomocysteinemia. The increase of homocysteine concentrations was particularly evident in young diabetic patients with AER >70 microg/min (fasting values: 14.7 +/- 5.6 micromol/L; after methionine load: 34.2 +/- 12.6 micromol/L) and in patients with proliferative retinopathy (fasting values: 15.1 +/- 5.0 micromol/L; after methionine load: 36.8 +/- 12.5 micromol/L). CONCLUSIONS: Increased plasma homocysteine concentrations may contribute to increased morbidity and death from cardiovascular disease in adolescents and young adults with diabetic retinopathy and nephropathy.     

Plasma homocysteine levels in children and adolescents with type 1 diabetes

OBJECTIVE: Hyperhomocysteinemia has been established as a risk factor for cardiovascular disease. The objective was to investigate total plasma homocysteine concentrations in children and adolescents with type 1 diabetes and a control group. METHOD: Twenty-seven children with type 1 diabetes and 27 subjects of an age- and sex-matched control group were recruited. Fasting samples were collected for plasma total homocysteine, serum vitamin B12, folate, and creatinine. RESULTS: Fasting total homocysteine concentrations showed no difference between patients and controls (5.6 +/- 2.9 micromol/L vs 5.7 +/- 2.2 micromol/L; p greater than 0.05). The diabetic patients had significantly higher serum folate than the healthy controls (11.4 +/- 3.3 ng/mL vs 9.4 +/- 4.1 ng/mL; P = 0.02 and higher serum B12 than the control group (282.8 +/- 119 pg/mL vs 228.5 +/- 50.9 pg/mL; P = 0.03). Total plasma homocysteine concentration correlated with age (r = 0.44, P = 0.02), weight (r = 0.56, P = 0.002), body mass index (r = 0.57, P = 0.002), folate (r = -0.48, P = 0.01), and creatinine (r = 0.41, P = 0.03) in diabetic patients. In stepwise multivariate regression model for diabetics, the independent correlates for total plasma homocysteine concentration was folate (P = 0.002). CONCLUSION: We concluded that fasting plasma total homocysteine concentrations were within normal limits in children and adolescents with type 1 diabetes who were without any clinical evidence of microvascular and macrovascular complications.     

二氢蝶啶还原酶缺乏症一例的诊治及基因突变分析

目的 探讨二氢蝶啶还原酶(DHPR)缺乏症的临床诊治和基因突变分析.方法 (1)归纳、总结临床症状、体征,血苯丙氨酸(Phe)浓度;(2)进行Phe(100 mg/kg)+四氢生物蝶呤(BH4)(20 mg/kg)负荷试验、尿蝶呤谱分析及红细胞DHPR测定;(3)进行DHPR基因QDPR突变检测;(4)采用BH4、神经递质前质等治疗,随访疗效.结果 (1)患儿男,生后5个月出现抬头困难、头发黄、抽 搐、肌张力低下.生后1岁6个月Phe 600 μmol/L;(2)负荷试验前血Phe浓度476 μmol/L,Phe负荷3 h上升至1355 μmol/L,BH4负荷24 h血Phe浓度缓慢降至610 μmol/L;(3)尿新蝶呤2.92 mmol/mol肌酐,生物蝶呤7.44 mmol/mol肌酐,生物蝶呤百分比71.79％;(4)DHPR活性(0.27～0.51)nmol/(min·5 mm disc),为正常对照的6.11％～10.60％,诊断为DHPR缺乏症;(5)患儿QDPR基因突变类型为c.515C＞T及c.661C＞T,c.515C＞T突变未见报道;(6)患儿普食下接受BH4(10～20)ms/(kg·d)或联合少量无Phe奶粉、神经递质前质L-DOPD(3～5)ms/(kg·d)(联合carbidopa)、5羟色氨酸(3～5)ms/(kg·d)及叶酸15 mg/d治疗.治疗6个月症状明显改善,抽搐停止、会扶走,血Phe 60 μmol/L.结论 (1)DHPR缺乏症具有肌张力低下等BH4缺乏症共同特点;(2)BH4负荷后血 Phe浓度下降缓慢;尿生物蝶呤增高,DHPR活性低下是确诊依据;(3)c.515C＞T(P172L)是QDPR基因新的致病突变;(4)神经递质前质、叶酸及大剂量BH4(或联合无Phe奶粉)治疗疗效显著.     

Glycogen storage disease type III with hypoketosis

A rare case of glycogen storage disease type III with unusually absent ketone body production during hypoglycemia is presented. A 10-month-old boy presented with asymptomatic hepatomegaly. GOT/GPT 2555/1160 IU/L, CK 302 IU/L, triglycerides 1223 mg/dL, cholesterol 702 mg/dL and uric acid 7.9 mg/dL. After a 9-hour fast, glucose was 27 mg/dL and adequate lipolysis without ketogenesis was observed (total/free carnitine 34.5/20 micromol/L, free fatty acids 1620 micromol/L and beta-hydroxybutyrate 172 micromol/L). Result of MCT (medium-chain triglycerides) load test: basal hydroxybutyrate 29 micromol/L rose to 5748 micromol/L. Treatment with a fat-restricted diet supplemented with formula containing MCT was initiated and the patient presented a satisfactory initial evolution. Three months later, CK were 3000 IU/L. Muscle biopsy was diagnostic of glycogenosis. Enzymatic activity in skin fibroblasts was 0% for amylo-1,6-glucosidase. The diagnosis of glycogenosis type III was established. Echocardiography performed at that time showed non-obstructive ventricular hypertrophy. Until now hypoketosis during hypoglycemia has only been described in glycogenosis type I.     

Mild neonatal hypoxia exacerbates the effects of vitamin-deficient diet on homocysteine metabolism in rats

Elevated plasma homocysteine has been linked to pregnancy complications and developmental diseases. Whereas hyperhomocysteinemia is frequently observed in populations at risk of malnutrition, hypoxia may alter the remethylation of homocysteine in hepatocytes. We aimed to investigate the combined influences of early deficiency in nutritional determinants of hyperhomocysteinemia and of neonatal hypoxia on homocysteine metabolic pathways in developing rats. Dams were fed a standard diet or a diet deficient in vitamins B12, B2, folate, month, and choline from 1 mo before pregnancy until weaning of the offspring. The pups were divided into four treatment groups corresponding to "no hypoxia/standard diet," "hypoxia (100% N2 for 5 min at postnatal d 1)/standard diet," "no hypoxia/deficiency," and "hypoxia/deficiency," and homocysteine metabolism was analyzed in their liver at postnatal d 21. Hypoxia increased plasma homocysteine in deficient pups (21.2 +/- 1.6 versus 13.3 +/- 1.2 microM, p < 0.05). Whereas mRNA levels of cystathionine beta-synthase remained unaltered, deficiency reduced the enzyme activity (48.7 +/- 2.9 versus 83.6 +/- 6.3 nmol/h/mg, p < 0.01), an effect potentiated by hypoxia (29.4 +/- 4.7 nmol/h/mg, p < 0.05). The decrease in methylene-tetrahydrofolate reductase activity measured in deficient pups was attenuated by hypoxia (p < 0.05), and methionine-adenosyltransferase activity was slightly reduced only in the "hypoxia/deficiency" group (p < 0.05). Finally, hypoxia enhanced the deficiency-induced drop of the S-adenosylmethionine/S-adenosylhomocysteine ratio, which is known to influence DNA methylation and gene expression. In conclusion, neonatal hypoxia may increase homocysteinemia mainly by decreasing homocysteine transsulfuration in developing rats under methyl-deficient regimen. It could therefore potentiate the well-known adverse effects of hyperhomocysteinemia.     

Plasma enteroglucagon in the control of childhood celiac disease

To study whether or not plasma enteroglucagon reflects changes of the small intestinal mucosa during different phases of celiac disease, we studied fasting and postprandial concentrations of plasma enteroglucagon, as well as small intestinal mucosa morphology, in children with celiac disease and in a reference group of children without gastrointestinal disorders. The children with celiac disease were studied before dietary treatment, during gluten-free diet, and during gluten challenge. In untreated celiac children we found high mean basal and postprandial plasma enteroglucagon concentrations compared with the reference group (p less than 0.001). After a gluten-free diet period of 0.2-4.5 years (mean, 1.0 year), when the small intestinal histology was normal or only mildly abnormal, there was a decrease of both mean basal plasma enteroglucagon concentration (from 81 to 17 pmol/L; p less than 0.001) and mean postprandial plasma enteroglucagon concentration (from 129 to 39 pmol/L; p less than 0.001). During a subsequent gluten challenge, which resulted in a mucosal relapse, there was a rise in mean postprandial plasma enteroglucagon concentration (from 39 to 74 pmol/L; p less than 0.005), although there was a substantial overlap in values from treated and challenged patients. These findings suggest that plasma enteroglucagon levels, particularly after a mixed meal, are correlated with the small intestinal mucosal morphology in childhood celiac disease. Determination of plasma enteroglucagon may facilitate the control of the dietary adherence during gluten-free diet and may in some children indicate mucosal relapse during gluten challenge. Thus, the number of control biopsies may be reduced.     

Effect of carbamazepine therapy on homocysteine, vitamin B12 and folic acid levels in children with epilepsy

Objectives

To compare the levels of homocysteine, vitamin B12 and folic acid before and after 6 months of carbamazepine therapy and to correlate them with carbamazepine level at 6 months.

Design

Prospective comparative study.

Setting

Tertiary care centre in North India.

Participants

51 children (2–12 years of age) presenting with motor partial seizures.

Intervention

Carbamazepine (10–20 mg/μ/day) for 6 months.

Main outcome measure

Change in serum homocysteine, B₁₂, folic acid level.

Methods

Fasting venous samples were collected before carbamazepine therapy and after six months. Homocysteine was analyzed using homocysteine enzyme immunoassay. Vitamin B₁₂ and folic acid were estimated using electrochemiluminesence technique. Carbamazepine levels were measured at 6 months.

Results

Of the 51 children, 36 (males-21), were followed up and their data analyzed. Mean homocysteine level was 11.51±3.95 μmol/L at recruitment and 11.77±6.65 μmol/L at six months (P=0.785). At recruitment 6(16%) children had homocysteine level above 15 μmol/L which increased to 10(27%) at 6 months. Mean vitamin B₁₂ at recruitment was 292.1±111.2 pg/mL and 297.8±82.9 pg/mL at 6 months (P=0.764). Mean folic acid at recruitment was 9.98±3.45 ng/mL and 10.66±3.97 ng/mL at 6 months (P=0.358). There was no correlation between carbamazepine levels with homocysteine, vitamin B₁₂ and folic acid (P>0.05). There was no effect of age, sex or dietary pattern on homocysteine levels.

Conclusion

Hence 6 months of carbamazepine therapy did not cause significant change in serum levels of homocysteine, vitamin B₁₂ and folic acid.     

Antioxidants and protein carbonyls in bronchoalveolar lavage fluid of children: normal data

Antioxidant-oxidant imbalances in bronchoalveolar lavage fluid (BAL) are thought to contribute to oxidative stress in respiratory disease. However, normal reference ranges for BAL antioxidants and oxidized proteins in children are not available. In this study, we recruited 124 children attending for elective surgery for a noninflammatory condition; 83 were nonasthmatic, nonatopic (N) and 41 were nonasthmatic, atopic (NA). A nonbronchoscopic lavage was performed and ascorbate, uric acid, alpha-tocopherol, and protein carbonyl (as a measure of oxidative damage) concentrations were determined in BAL fluid. The 95% reference range was 0.112-1.897 micromol/L for ascorbate, 0.149-2.163 micromol/L for urate, 0.0029-0.066 micromol/L for alpha-tocopherol, and 0.280-4.529 nmol/mg for protein carbonyls in BAL fluid. Age, gender, and exposure to environmental tobacco smoke did not affect the concentration of ascorbate, urate, alpha-tocopherol, or protein carbonyls. However, in multiple linear regression analyses, the type of home heating (glass-fronted fires or oil-fired central heating) was found to influence ascorbate and urate concentrations in the BAL fluid (ss-coefficient for ascorbate: 0.445, p = 0.031; for urate: 0.114, p = 0.001). There was no significant difference between the N and NA group in BAL fluid concentrations of ascorbate, urate, or protein carbonyls. The alpha-tocopherol concentration was significantly increased in the NA group (p = 0.037). Uric acid and alpha-tocopherol concentrations in BAL fluid and serum were not correlated. Intriguingly, serum and BAL ascorbate concentrations were significantly correlated (r = 0.297, p = 0.018, n = 63), which may offer an explanation for why supplementing the diet with vitamin C can improve asthma symptoms. Further studies will investigate the role of BAL antioxidant concentrations in children with inflammatory respiratory diseases.     

Influence of folic acid on birthweight and growth of the erythroblastotic infant. III. Effect of folic acid supplementation.

Seventeen infants with severe (14) or moderately severe (3) erythroblastosis were given daily oral supplements of 2-5 or 5 mg folic acid from day 16 (average) to 3-2 months (average). Their rate of weight gain, expressed as weight centiles, was followed for 1 year and was compared with that of a very similar group of 34 erythroblastotic infants without folic acid supplements. By the end of the 4th month, just after stopping additional folate intake, the median centiles for weight had risen from the 40th to the 80th centile, while in the untreated control group they rose during this period from the 35th to the 50th centile. During the second half of the year both groups declined in weight centiles, the ''treated'' group ending up at the 50th centile for weight, while the control group fell to the 25th.     

Double-blind, placebo-controlled trial comparing effects of supplementation with two different combinations of micronutrients delivered as sprinkles on growth, anemia, and iron deficiency in cambodian infants

OBJECTIVES: To assess and compare efficacy of two micronutrient sprinkle supplementation on growth, anemia, and iron deficiency in Cambodian infants. METHODS: A total of 204 infants aged 6 months and living in Kompong Chhnang Province, Cambodia were randomly assigned to receive daily supplements of either iron (12.5 mg) plus folic acid (150 mug) plus zinc (5 mg) (MMN, n = 68), or iron (12.5 mg) plus folic acid (150 microg) alone (FFA, n = 68), or placebo (n = 68) for a 12 month period in powder form as sprinkles. Anthropometrics was evaluated bimonthly. Biochemical assessment was performed at baseline and at the end of intervention period. RESULTS: At baseline, the overall mean (SD) of hemoglobin concentration was 101 g/L. No difference among groups was found for growth pattern. Significant decline was observed for weight-for-age and height-for-age z-scores in any group (P < 0.0001). The rate of recovery from anemia was significant (P < 0.001) and comparable between MMN (54%) and FFA (53%) groups and higher than in the placebo group (22%, P < 0.0001). Through the study period, no significant change in the rate of iron deficiency was found in MMN and FFA groups, whereas it increased in the placebo group (31%, baseline vs. 52%, end of study; P < 0.0001). CONCLUSION: Both MMN and FFA supplements were effective for preventing or treating anemia in Cambodian infants and stabilizing plasma levels of ferritin. Use of micronutrients in a controlled home setting, as sprinkled daily supplements, may be promising in preventing and treating anemia in developing countries.     

Folic acid supplements in vitamin tablets: a determinant of hematological drug tolerance in maintenance therapy of childhood acute lymphoblastic leukemia

Methotrexate (MTX) is an antifolate that inhibits cell division by reducing intracellular amounts of reduced tetrahydrofolates. Of 53 children with acute lymphoblastic leukemia (ALL) in maintenance treatment with MTX and 6-mercaptopurine (6-MP), 25 had received daily folic acid supplements in vitamin tablets containing 75-200 micrograms folic acid for at least the preceding 3-month period. Experimental data have shown that increased folate concentrations intracellularly inhibit MTX metabolism and toxicity. Therefore we found it relevant to investigate the extent to which folic acid supplements affect hematological tolerance to MTX and 6-MP in children during maintenance therapy for ALL. The erythrocyte folate (ery-folate) concentration was significantly higher in children who received extra folic acid than in those who did not (p less than 0.001). The ery-folate in MTX-treated children was only marginally reduced compared with the controls. The erythrocyte methotrexate (ery-MTX) concentration correlated with the weekly dose of MTX but not with any of the investigated hematological parameters. Children who received vitamin tablets containing folic acid had higher thrombocyte counts (p = 0.0056), higher leukocyte counts (p = 0.06), higher neutrophil counts (p = 0.05), and lower erythrocyte mean cell volumes (p = 0.05) than children who received no folic acid. We conclude that folic acid supplements of 75-200 micrograms/day affect the proliferative capacity of the bone marrow. Since none of the children was folate deficient as judged by the ery-folate, we recommend that vitamins given to children in maintenance treatment with MTX and 6-MP for ALL should not contain folic acid.(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of micronutrient supplements among pregnant women in Alberta: results from the Alberta Pregnancy Outcomes and Nutrition (APrON) cohort

Maternal nutrient intake in the prenatal period is an important determinant of fetal growth and development and supports maternal health. Many women, however, fail to meet their prenatal nutrient requirements through diet alone and are therefore advised to consume nutrient supplements. The purpose of this study was to describe the use of natural health products (NHP) by pregnant women in each trimester of pregnancy. Women (n = 599) participating in the first cohort of the Alberta Pregnancy Outcomes and Nutrition (APrON) study completed an interviewer‐administered supplement intake questionnaire during each trimester of pregnancy. NHP use was high, with >90% taking multivitamin/mineral supplements, and nearly half taking at least one additional single‐nutrient supplement. Compliance with supplementation guidelines was high for folic acid (>90%), vitamin D (～70%) and calcium (～80%), but low for iron (<30%) and for all four nutrients together (≤11%). On average, women met or exceeded the recommended dietary allowance for folic acid, vitamin D and iron from NHPs alone, with median daily intakes of 1000 μg, 400 IU and 27 mg, respectively. The median calcium intake was 250 mg d^?1. Up to 26% of women exceeded the tolerable upper intake level for folic acid and up to 19% did so for iron at some point of their pregnancy. Findings highlight the need to consider both dietary and supplemental sources of micronutrients when assessing the nutrient intakes of pregnant women.     

Buthionine sulfoximine and myeloablative concentrations of melphalan overcome resistance in a melphalan-resistant neuroblastoma cell line

BACKGROUND: Alkylator resistance contributes to treatment failure in high-risk neuroblastoma. Buthionine sulfoximine (BSO) can deplete glutathione and synergistically enhance in vitro sensitivity to the alkylating agent melphalan (L-PAM) for many neuroblastoma cell lines, but optimal use of this combination needs to be defined because clinical responses have been less frequent and not durable. PATIENTS AND METHODS: The authors established and characterized a neuroblastoma cell line (CHLA-171) from a patient who died of progressive disease after treatment with BSO and low-dose L-PAM. RESULTS: CHLA-171 lacks MYCN amplification, expresses PGP (P-glycoprotein) 9.5 RNA, and shows cell surface antigen expression (human leukocyte antigen class I weakly positive, but HSAN 1.2 (hybridoma, SAN 1.2) and anti-GD2 (anti-ganglioside GD2 antibody) strongly positive) characteristic of neuroblastoma cell lines. Twenty-four hours of BSO treatment (0-1,000 micromol/L) maximally depleted CHLA-171 glutathione to 36% of baseline. The cytotoxic response of CHLA-171 to BSO and L-PAM, alone and in combination, was measured by digital image microscopy (DIMSCAN) over a range of drug concentrations and compared with drug levels obtained in the patient during BSO/L-PAM therapy. As single agents, CHLA-171 was highly resistant to L-PAM (LD90 = 42 micromol/L; peak plasma concentration in the patient equals 3.9 micromol/L) and moderately resistant to BSO (LD90 = 509 micromol/L; steady-state concentration in the patient equals 397 micromol/L). Treatment with a 10:1 (BSO:L-PAM) fixed ratio combination synergistically overcame resistance (3-4 logs of cell kill, combination index <1) at clinically achievable levels of BSO (100-400 micromol/L) and levels of L-PAM (10-40 micromol/L) clinically achievable only with hematopoietic stem cell support. CONCLUSIONS: The in vitro results obtained for CHLA-171 suggest that BSO/L-PAM therapy may be optimally effective for drug-resistant neuroblastoma using myeloablative doses of L-PAM.     

窒息新生儿血清同型半胱氨酸与叶酸的变化

目的：探讨血清中高同型半胱氨酸（Hcy）血症及低叶酸水平与新生儿窒息的发生是否具有相关性,并对性别、胎龄等因素对血清中同型半胱氨酸及叶酸水平是否有一定影响进行分析。方法：应用酶联免疫吸附实验方法检测血清中Hcy水平,应用放射免疫法测定血中叶酸浓度。结果：①与无窒息对照组相比, 新生儿窒息患儿血清Hcy水平显著升高,而叶酸水平显著降低;②窒息组男婴血清Hcy、叶酸水平分别为15.82 ±2.51 μmol/L; 2.49 ±0.19 ng/mL,女婴为10.50±2.19 μmol/L; 2.38±0.40 ng/mL,男、女婴之间比较差异无显著性;③窒息组足月儿血清Hcy、叶酸水平为12.34 ±2. 01 μmol/L,2.58 ±0.19 ng/mL;早产儿为21.25±5.01 μmol/L; 2.14±0.34 ng/mL。早产儿Hcy水平显著高于足月儿（P<0.05）。结论：①新生儿窒息与血清Hcy及叶酸水平具有显著相关性。②血清Hcy及叶酸水平在性别上无显著差异。③缺氧窒息合并早产者血清Hcy水平升高最为显著。     

甲基丙二酸尿症合并同型半胱氨酸血症57例临床分析

目的对57例甲基丙二酸尿症合并同型半胱氨酸血症患者进行回顾性研究。方法1996～2006年就诊的96例甲基丙二酸尿症患者中57例（59.4％）合并同型半胱氨酸血症,来自中国大陆16个省市,其中男32例,女25例,通过尿液、血液生化分析诊断,尿液有机酸测定采用GCMS分析技术,血清、尿液总同型半胱氨酸检测采用荧光偏振免疫测定法。结果57例患者尿中甲基丙二酸均显著增高,血清总同型半胱氨酸81.5～226.5μmol／L（正常对照4.5～12.4μmol／L）,尿液总同型半胱氨酸79.1～414.5μmol／L（正常对照1.0～20.0μmol／L）。其中13例（22.8％）于新生儿期发病,临床表现类似缺血缺氧性脑病;14例（24.6％）于1个月-1岁内发病,以神经系统损害为主要表现;9例（15.8％）于1岁～学龄前发病,以智力运动倒退为主要表现;18例（31.6％）于6～15岁发病,其中7例合并肝、肾、周围神经等多脏器损害。3例（5.3％）分别于16、24、34岁出现进行性智力运动倒退等异常。57例患者中11例（19.3％）死亡。46例（80.7％）接受维生素B12、叶酸、左旋肉碱、甜菜碱补充治疗,逐渐好转,11例（19.3％）完全康复。结论甲基丙二酸尿症合并同型半胱氨酸血症是中国人甲基丙二酸尿症的常见类型,患者个体差异大,可于新生儿期至成年各个时期发病,临床诊断困难。对于甲基丙二酸尿症患者应及早进行血浆、尿液总同型半胱氨酸测定,鉴别诊断,合理治疗。     

Neonatal onset methylmalonic aciduria and homocystinuria:Biochemical and clinical improvement with betaine therapy

Methylmalonic aciduria and homocystinuria is a very rare inborn error of cellular cobalamin (Cbl) metabolism. We describe the biochemical evolution and clinical course of a boy with neonatal onset CblC mutant defect.Born after a normal pregnancy, the patient developed general hypotonia and severe feeding difficulties at 5 days of life. Diagnosis of methylmalonic aciduria and homocystinuria was established by amino-acid and organic acid analysis and was confirmed by enzyme and genetic studies. The patient was initially treated with parenteral hydroxocobalamin (1 mg/day), oral carnitine (100 mg/kg/day) and a restricted protein diet. This treatment returned methylmalonic acid levels to normal. Despite the parenteral hydroxocobalamin therapy, the patient showed no improvement in neurological dysfunction, hypotonia or developmental delay. Oral betaine supplementation (3 g/day) from months 3-15 reduced plasma total homocysteine and homocystinuria. The patient showed clinical improvement in neurological and growth development. We conclude that early betaine therapy was safe and effective in our patient with neonatal onset methylmalonic aciduria and homocystinuria type CblC.     

Hyperinsulinism and hyperammonemia syndrome: report of twelve unrelated patients

Hyperinsulinism and hyperammonemia syndrome has been reported as a cause of moderately severe hyperinsulinism with diffuse involvement of the pancreas. The disorder is caused by gain of function mutations in the GLUD1 gene, resulting in a decreased inhibitory effect of guanosine triphosphate on the glutamate dehydrogenase (GDH) enzyme. Twelve unrelated patients (six males, six females) with hyperinsulinism and hyperammonemia syndrome have been investigated. The phenotypes were clinically heterogeneous, with neonatal and infancy-onset hypoglycemia and variable responsiveness to medical (diazoxide) and dietary (leucine-restricted diet) treatment. Hyperammonemia (90-200 micromol/L, normal <50 micromol/L) was constant and not influenced by oral protein, by protein- and leucine-restricted diet, or by sodium benzoate or N-carbamylglutamate administration. The patients had mean basal GDH activity (18.3 +/- 0.9 nmol/min/mg protein) not different from controls (17.9 +/- 1.8 nmol/min/mg protein) in cultured lymphoblasts. The sensitivity of GDH activity to inhibition by guanosine triphosphate was reduced in all patient lymphoblast cultures (IC(50), or concentrations required for 50% inhibition of GDH activity, ranging from 140 to 580 nM, compared with control IC(50) value of 83 +/- 1.0 nmol/L). The allosteric effect of ADP was within the normal range. The activating effect of leucine on GDH activity varied among the patients, with a significant decrease of sensitivity that was correlated with the negative clinical response to a leucine-restricted diet in plasma glucose levels in four patients. Molecular studies were performed in 11 patients. Heterozygous mutations were localized in the antenna region (four patients in exon 11, two patients in exon 12) as well as in the guanosine triphosphate binding site (two patients in exon 6, two patients in exon 7) of the GLUD1 gene. No mutation has been found in one patient after sequencing the exons 5-13 of the gene.