尿毒症血液透析患者的卡尼汀缺乏以及左卡尼汀的补充治疗作用

探讨尿毒症血液透析患者的卡尼汀代谢并观察补充左卡尼汀的作用。方法取透析前后血测血浆游离卡尼汀浓度,研究卡尼汀与血液透析时间,肌酐清除率、食欲及透析中低血压,肌痉挛和透析后虚弱无力的关系;左卡尼汀补充３个月,观察血浆ＦＣ浓度变化和临床症状的改善。     

A genomic approach to mutation analysis of holocarboxylase synthetase gene in three Chinese patients with late-onset holocarboxylase synthetase deficiency

OBJECTIVE: Multiple carboxylase deficiency (MCD, MIM:253270) is a common organic aciduria and caused by deficiency of either biotinidase or holocarboxylase synthetase (HLCS; EC 6.3.4.10). Patients commonly present during early infancy with acute metabolic derangements and severe metabolic acidosis. Recently, a late onset form of HLCS deficiency was also described. The different phenotypes (early and late presenting) may be related to a spectrum of mutations in HLCS gene. Applications of mutation analysis in HLCS had been limited previously by the requirement of cDNA from living tissue for study. We described here a genomic approach for molecular diagnosis of HLCS deficiency which we have used to detect mutations in Chinese patients who had the late-onset form of HLCS deficiency. In addition, a fibroblast cell line with MCD from Coriell Cell repositories was also studied. DESIGN AND METHODS: Three Chinese patients with late onset HLCS deficiency were studied. The genomic sequence of HLCS was retrieved and newly designed primers were used to cover all coding sequences of the gene. PCR products were analyzed by direct sequencing. Population allelic frequencies of mutations detected were determined by genotyping of control samples by restriction fragment length polymorphism. RESULTS: We found a recurrent mutation, R508W, in the three unrelated Chinese patients. Two were homozygous for this mutation. The other patient was a compound heterozygote of R508W and a novel mutation, D634N. The results suggest that R508W may be an important and relatively prevalent disease-causing mutation in Chinese MCD patients. A fibroblast cell-line from an African patient revealed an additional novel mutation, R565X and a known mutation, V550M. CONCLUSION: R508W is a recurrent mutation in Chinese MCD patients which is associated with the late onset phenotype. This new genomic approach for mutation analysis of HLCS gene provides new opportunities in studies of MCD.     

Organic acidemias: a methylmalonic and propionic focus

The management of children with organic acidemias (OAs) is limited in nursing literature. This article focuses on the two more common OAs, methylmalonic and propionic acidemias. Literature search was done on PUBMED, CINAHL, OVID, UptoDate, and GeneReview. The benefit of early diagnosis and treatment has been well documented, but many unresolved aspects of care management remain. Patient care is a complex necessitation and a lifelong follow-up for complications. Caring for patients with OA requires that nurses increase their familiarity with metabolic genetics and develop a better understanding of proper medical and nursing management while research continues to determine the most beneficial treatment and long-term care management methods.     

Determination of free and total carnitine in plasma by an enzymatic reaction and spectrophotometric quantitation spectrophotometric determination of carnitine

OBJECTIVES: Carnitine initiates the beta-oxidation of fatty acids and its deficiency is a problem in several metabolic diseases. This work describes a validated quick and simple enzymatic assay for the determination of free and total carnitine in plasma. METHODS: Carnitine reacts with acetyl-CoA catalized by carnitine acetyltransferase. The coenzyme A liberated combines with 5,5'-dithiobis-(2-nitrobenzoic acid) and forms thiophenolate ion, measured spectrophotometrically at 412 nm. The method requires precipitation of proteins and the alkaline hydrolysis of acylcarnitines for total carnitine. RESULTS: The detection limit is 1.7 micromol/L in plasma and inter- and intra-day imprecision is less than 5%. The recovery of spiked plasma samples is 97%. The method was tested with an inter-laboratory assay, yielding excellent correlation (r(2)=0.994), and it was applied to the determination of normal values of carnitine in plasma. CONCLUSIONS: A reliable spectrophotometric method has been validated with very good precision, with simple instrumental and easy sample preparation.     

Urine methylmalonic acid measurements for the assessment of cobalamin deficiency related to neuropsychiatric disorders

BACKGROUND: Detection of cobalamin deficiency is clinically important for a better understanding of neuropsychiatric diseases, and why the deficiency occurs more frequently than previously anticipated. However, serum cobalamin measurements have a limited ability to diagnose a deficiency state. OBJECTIVE: To evaluate functional cobalamin status in neuropsychiatric patients using an appropriate photometric urine methylmalonic acid (MMA) determination method that could be easily adapted to all routine clinical laboratories. METHODS: We modified the old photometric method used for determining urinary MMA concentrations. MMA measurements were made in first morning urine samples with normalizing by creatinine concentrations. The serum cobalamin, total homocysteine (tHcy), folate, red cell folate, and urinary MMA concentrations taken from 17 psychosis, 28 depression, 16 dementia patients and 47 healthy people were analyzed using the ROC, correlation and multiple regression analysis.RESULTS: The modified method was found to have better recovery (96-103%) and CV% values than the old method. Mean +/- SDs of uMMA and cobalamin concentrations were 11.49 +/- 4.93 mmol/mol creatinine, and 231 +/- 151 pg/mL in psychosis and depression group, and 6.04 +/- 1.93 mmol/mol creatinine and 308 +/- 140 pg/mL in control group, respectively. Those in the dementia group were 11.53 +/- 4.0 mmol/mol creatinine and 231 +/- 84 pg/mL, and in the control group 6.05 +/- 1.94 mmol/mol creatinine and 364 +/- 188 pg/mL. There was a good correlation between urinary MMA and serum Vitamin B(12) determinations for all groups at a confidence level (p) of 99%. The correlation between urinary MMA and red cell folate was also significant at p = 95% for depression, psychosis and control groups, and p = 99% for dementia group. In the ROC analyses, area under the curve values for uMMA, B12 and tHcy were 0.842, 0.796 and 0.728, respectively. CONCLUSIONS: A sensitive and easy photometric method has been presented. When cobalamin deficiency is suspected in neuropsychiatric patients, photometric urinary MMA determination analysis can be the first diagnostic test used. If the urinary MMA concentration is above the reference value, serum cobalamin levels can be determined for further diagnosis.     

Traumatic brain injury as a relevant cause of growth hormone deficiency in adults: A KIMS-based study

OBJECTIVES: To characterize further the clinical manifestations and the efficacy of growth hormone (GH) replacement therapy in patients with adult-onset growth hormone deficiency (GHD) reported in the KIMS (Pfizer's international metabolic database) as caused by traumatic brain injury (TBI) and to compare them with nonirradiated patients whose GHD was due to a nonfunctioning pituitary adenoma (NFPA). DESIGN: Observational study. SETTING: Subjects selected from the KIMS database. PARTICIPANTS: Fifty-one patients with GHD resulting from TBI and 688 patients with GHD resulting from NFPA. Both groups were selected from the KIMS and had adult-onset GHD with GH replacement therapy only after KIMS entry and before and after KIMS entry. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Age, body mass index, age at disease onset, age at disease diagnosis, age at KIMS entry, final height, GH peak at testing, GH replacement dose, routine biochemical analysis, clinical manifestations of disease, and quality of life measurements. RESULTS: Patients with TBI were significantly younger at study entry and were younger both at pituitary disease onset and at GHD diagnosis, but they showed a significant delay in treatment. When comparing patients not treated with GH before entering in the KIMS, patients with TBI were significantly shorter (167.2+/-1.7 cm) than those with NFPA (171.6+/-0.4 cm) in final height. TBI patients had lower GH reserves than NFPA patients, and although the latter group experienced more positive changes, both groups benefited from GH replacement therapy. CONCLUSIONS: Patients with GHD due to TBI showed a significant reduction in height and a reduction in pituitary GH reserve and were diagnosed and treated with inappropriate delay.     

Deep vein thrombosis associated with protein C and protein S deficiency: an unusual cause of acute abdomen

Deep venous thrombosis is an extremely rare cause of acute abdomen and is often difficult to diagnose. Protein C and protein S deficiencies are rare genetic abnormalities that predispose the patient to thrombophilia and lead to thrombosis. We report the case of a previously healthy 7-year-old boy with iliofemoral thrombosis due to protein C and protein S deficiencies mimicking acute abdomen.     

Immunohistochemical determination of the extracellular matrix modulation in a rat model of choline‐deprived myocardium: the effects of carnitine

Choline has been identified as an essential nutrient with crucial role in many vital biological functions. Recent studies have demonstrated that heart dysfunction can develop in the setting of choline deprivation even in the absence of underlying heart disease. Matrix metalloproteinases (MMPs) are responsible for extracellular matrix degradation, and the dysregulation of MMP‐2 and MMP‐9 has been involved in the pathogenesis of various cardiovascular disorders. The aim of the study was to investigate the role of MMPs and their inhibitors (TIMPs), in the pathogenesis of choline deficiency‐induced cardiomyopathy, and the way they are affected by carnitine supplementation. Male Wistar Albino adult rats were divided into four groups and received standard or choline‐deficient diet with or without L‐carnitine in drinking water (0.15% w/v) for 1 month. Heart tissue immunohistochemistry for MMP‐2, MMP‐9, TIMP‐1, and TIMP‐2 was performed. Choline deficiency was associated with suppressed immunohistochemical expression of MMP‐2 and an increased expression of TIMP‐2 compared to control, while it had no impact on TIMP‐1. MMP‐9 expression was decreased without, however, reaching statistical significance. Carnitine did not affect MMP‐2, MMP‐9, TIMP‐1 or TIMP‐2 expression. The pattern of TIMP and MMP modulation observed in a choline deficiency setting appears to promote fibrosis. Carnitine, although shown to suppress fibrosis, does not seem to affect MMP‐2, MMP‐9, TIMP‐1 or TIMP‐2 expression. Further studies will be required to identify the mechanism underlying the beneficial effects of carnitine.     

足月高胆红素血症新生儿的血液氨基酸和酰基肉碱水平变化及其意义

目的探讨足月高胆红素血症新生儿的血液氨基酸和酰基肉碱水平变化及其意义。方法选取2010年3月至2014年7月治疗的足月高胆红素血症新生儿450例,同时选取健康新生儿310名作为对照组。比较两组新生儿的血液氨基酸和酰基肉碱水平。结果其中观察组丙氨酸、亮氨酸-异亮氨酸、脯氨酸、色氨酸、苏氨酸水平明显高于对照组(P0.05),而天冬氨酸、精氨酸、瓜氨酸和半胱氨酸水平明显低于对照组(P0.05);观察组丙酰基肉碱、乙酰基肉碱、丁酰基肉碱、羟丁酰基肉碱、羟异戊酰基肉碱、戊二酰基肉碱、已酰基肉碱、辛酰基肉碱和肉豆蔻酰基肉碱水平显著高于对照组(P0.05),而游离肉碱、二十二碳酰基肉碱和二十六碳酰基肉碱水平低于对照组(P0.05)。脯氨酸与酰基肉碱在两组新生儿中无相关性(P0.05)。结论足月高胆红素血症新生儿的血液氨基酸和酰基肉碱水平相对与健康新生儿存在一些变化,可为临床治疗和诊断提供一些依据。     

Macro creatine kinase in a case of carnitine palmitoyltransferase deficiency

A stout man was admitted to the hospital with acute rhabdomyolysis associated with macro creatine kinase (macro-CK, EC 2.7.3.2). This anomaly of CK was detected by gel electrophoresis as an atypical band between CK-MB and CK-MM, classified according to Stein's criteria (Clin Chem 1982; 28:19-24) as type 1, and identified by immunofixation electrophoresis as containing CK isoenzymes MM and MB and immunoglobulin A. Muscle biopsy showed that the etiology of rhabdomyolysis in this case was deficiency of carnitine palmitoyltransferase (CPT, EC 2.3.1.21) in the muscle. We report the first observation of macro-CK in a case of CPT deficiency; its presence may result from recurrent rhabdomyolytic attacks owing to CPT deficiency, and may suggest underlying enzymic abnormality in muscle.     

Dynamic adaptive changes of the serum carnitine esters during and after L-carnitine supplementation in patients with maintenance haemodialysis

Abstract

Background. Here we report the serum carnitine ester profile during and after 1g iv/day L-carnitine supplementation in haemodialysis patients. Materials and methods. Seven patients were studied over 29 weeks. After a control day, 12 weeks of replacement therapy was introduced followed by 17 weeks of washout period. The serum acylcarnitine concentrations were determined by isotope dilution ESI MS/MS technique. Results. At baseline significantly decreased free carnitine (48%, p < 0.01) and a 1.5–16-fold elevation of 16 out of 27 acylcarnitines were detected in HD patients compared with the controls. On the last day of L-carnitine supplementation a 1.6–4.8-fold increase was observed in the acylcarnitine levels compared with day 0; the increase-profile was achieved in four different patterns. The increase rate was rapid and early saturable for C5, C5OH, C6DC, C8:1, C10DC and C18:2 esters, slower for C2, C4, C6, C18 and C18:1 esters, it was slowest and reached a late plateau for C3, C8DC, C14:2, C16 and C16:1, and finally almost gradual increase was seen for 11 acylcarnitines. Three months after the cessation of carnitine treatment marked concentration drops were found for almost all acylcarnitines (by 11–74 % of week 12, p < 0.05); the values further decreased over the five remaining weeks of the observation period. Conclusion. Carnitine administration affected the levels of circulating esters in different dynamics and kinetics suggesting a regulated, non-random adaptive reallocation of nutrients. A considerable washout was achieved 3 months after discontinuation of the supplementation; however, the profile still was suggestive for presence of rest of accumulated supplement.     

Comparison of cytosolic and mitochondrial enzyme alterations in the livers of propionic or methylmalonic acidemia: a reduction of cytochrome oxidase activity

The activities of mitochondrial, cytosolic and microsomal enzymes in liver specimens obtained from three patients with propionic or methylmalonic acidemia were compared with those of control patients who had died from unrelated causes. Only the activity of cytochrome oxidase (mitochondrial enzyme) was significantly reduced in the patients of propionic acidemia and methylmalonic acidemia who were in the state of metabolic acidosis; in two patients the activity was less than 30% of that in controls, but in the other patient of propionic acidemia, who was under the treatment with a low protein diet (0.8 g/kg/day), the activity was 50% of that in controls. The metabolites of branched chain amino acids (tiglic acid, propionic acid, methylmalonic acid, succinic acid, tiglyl-CoA and propionyl CoA) exhibited no inhibitory effect on the cytochrome oxidase activity of the sonicated rat liver mitochondria. The reduction of cytochrome oxidase activity found in these organic acidemias may be caused secondarily by some unknown mechanism.     

Whole body fat oxidation before and after carnitine supplementation in uremic patients on chronic haemodialysis

Summary. This study has evaluated whether uremic patients on chronic haemodialysis with subnormal plasma levels of free carnitine show any alterations in whole body fat oxidation before and after one week with carnitine supplementation (60 mg/kg/day). Carnitine plasma levels changed from subnormal to supranormal levels of both free and total carnitine concentrations. This increase was not associated with any alteration in either oxygen uptake, carbon dioxide production, respiratory quotient or blood substrate levels such as glucose, glycerol, free fatty acids and lactate. The fractional oxidation of an intravenously infused fat emulsion (Intralipid®) was 17% before and 19% after carnitine supplementation. No side effects were observed in spite of the rather high dose of carnitine administration. This study failed to demonstrate any impact on net whole body fat oxidation in carnitine substituted uremic patients with initially subnormal levels of free plasma carnitine.     

Vitamin B(12) deficiency as a cause of delirium in a patient with spinal cord injury

Harrington AL, Dixon TM, Ho CH. Vitamin B₁₂ deficiency as a cause of delirium in a patient with spinal cord injury.A man with spinal cord injury (SCI) and multiple medical comorbidities had new-onset delirium during his 14th month of hospitalization. Diagnostic workup did not elicit an obvious etiology for mental status changes. Delirium persisted despite psychiatry intervention, and he was unable to be weaned from the ventilator because of prolonged agitation. Routine anemia workup revealed a possible untreated vitamin B₁₂ deficiency, although laboratory values were inconclusive. Empiric treatment with cyanocobalamin injections was initiated, and his delirium remarkably resolved after 3 weeks of treatment. We provide a concise review of the etiologies and varied clinical presentations of vitamin B₁₂ deficiency. As illustrated in this case, classic laboratory findings may not appear, and neurologic impairments from SCI can obscure the physical signs of deficiency, making diagnosis difficult. Empiric treatment may be indicated in cases of neuropsychiatric abnormalities not explained by other causes.     

Primary carnitine deficiency with severe acute hepatitis following rotavirus gastroenteritis

Rotavirus infection is a major cause of gastroenteritis, which occurs mainly in children. Liver dysfunction due to rotavirus gastroenteritis has been reported; however, acute hepatitis due to this disease is very rare. We present a rare case in which rotavirus gastroenteritis led to sequential diagnosis of acute hepatitis and systemic primary carnitine deficiency (CDSP) in a 1-year-old girl. The patient's symptoms (hypoglycemia, hepatomegaly, and elevated levels of serum transaminases and creatinine kinase) suggested a steatosis causing liver dysfunction. She was initially considered to have a beta oxygenation defect or secondary carnitine deficiency caused by pivalic acid-containing antibiotics; however, repetitive carnitine analysis and free carnitine clearance measurement confirmed primary carnitine deficiency (carnitine transporter deficiency). Children with severe liver dysfunction due to rotavirus infection and presenting with liver steatosis should undergo blood acyl carnitine analysis to detect potential carnitine or other beta oxidation deficiencies, especially if newborn screening for these diseases is not available.     

Potassium disturbances as a cause of metabolic neuromyopathy

We report two cases of ascending muscular weakness progressing to areflexic quadriplegia caused by severe derangement of potassium homeostasis. The first patient presented with a 17-alpha-hydroxylase deficiency and severe hypokalemia. The second case had primary adrenocortical deficiency (Addison's disease) and extreme hyperkalemia. Complete recovery ensued after correction of the metabolic disorder in both cases. The role of potassium in the pathophysiology of neuromuscular excitation is discussed. We conclude that when neuromyopathy is present, metabolic causes should be considered and the serum potassium determined.     

Changes in blood carnitine and acylcarnitine profiles of very long-chain acyl-CoA dehydrogenase-deficient mice subjected to stress

BACKGROUND: In humans with deficiency of the very long-chain acyl-CoA dehydrogenase (VLCAD), C14-C18 acylcarnitines accumulate. In this paper we have used the VLCAD knockout mouse as a model to study changes in blood carnitine and acylcarnitine profiles under stress. DESIGN: VLCAD knockout mice exhibit stress-induced hypoglycaemia and skeletal myopathy; symptoms resembling human VLCADD. To study the extent of biochemical derangement in response to different stressors, we determined blood carnitine and acylcarnitine profiles after exercise on a treadmill, fasting, or exposure to cold. RESULTS: Even in a nonstressed, well-fed state, knockout mice presented twofold higher C14-C18 acylcarnitines and a lower free carnitine of 72% as compared to wild-type littermates. After 1 h of intense exercise, the C14-C18 acylcarnitines in blood significantly increased, but free carnitine remained unchanged. After 8 h of fasting at 4 degrees C, the long-chain acylcarnitines were elevated 5-fold in knockout mice in comparison with concentrations in unstressed wild-type mice (P < 0.05), and four out of 12 knockout mice died. Free carnitine decreased to 44% as compared with unstressed wild-type mice. An increase in C14-C18 acylcarnitines and a decrease of free carnitine were also observed in fasted heterozygous and wild-type mice. CONCLUSIONS: Long-chain acylcarnitines in blood increase in knockout mice in response to different stressors and concentrations correlate with the clinical condition. A decrease in blood free carnitine in response to severe stress is observed in knockout mice but also in wild-type littermates. Monitoring blood acylcarnitine profiles in response to different stressors may allow systematic analysis of therapeutic interventions in VLCAD knockout mice.