Carbohydrates :: deficiency
Tomohiro Kumada, Tomoko Miyajima, Nobusuke Kimura, Keiko Saito, Hideki Shimomura, Nozomi Oda, Tatsuya Fujii
Department of Pediatrics, Shiga Medical Center for Children, Shiga, Japan. email@example.com
The authors describe the use of a modified Atkins diet for the treatment of 2 children with nonconvulsive status epilepticus. Patient 1 was a 4-year-and-11-month-old girl diagnosed with frontal lobe epilepsy. Since the age of 3 years and 10 months, she had daily nonconvulsive status epilepticus resistant to antiepileptic agents. Patient 2 was a 5-year-and-5-month-old girl with subcortical band heterotopia. She had nonconvulsive status epilepticus daily since the age of 5 years. They were treated with the modified Atkins diet, in which carbohydrate intake was restricted to 10 g/d without restriction on protein, caloric, or fluid intake. The nonconvulsive status epilepticus disappeared 5 and 10 days after the initiation of the diet treatment, respectively. They have been on the diet treatment and free from nonconvulsive status epilepticus for 19 and 4 months, respectively. The modified Atkins diet appears to be very effective for the treatment of nonconvulsive status epilepticus.
Most cited papers:
Department of Pediatrics, University of Leuven, Belgium.
The carbohydrate-deficient glycoprotein (CDG) syndromes are a newly recognized family of diseases with autosomal recessive inheritance. The basic defects are probably in the glycosylation pathway (endoplasmic reticulum, Golgi apparatus or post-Golgi). In the present state of our knowledge the central nervous system is always severely affected but nearly all other organs are involved to a variable degree. Like the peroxisomal disorders they also comprise dysmorphic features, the most typical being an abnormal distribution of subcutaneous adipose tissue. A reliable diagnostic test is isoelectric focusing of serum transferrin showing a cathodal shift as a consequence of the partial sialic acid deficiency. Prenatal diagnosis and heterozygote detection are not yet available. These diseases should be differentiated from secondary CDG syndromes such as classical galactosaemia.
14-3-3s regulate global cleavage of their diverse binding partners in sugar-starved Arabidopsis cells.
Medical Research Council Protein Phosphorylation Unit, Department of Biochemistry, MSI/WTB Complex, University of Dundee, Dundee DD1 5EH, UK.
Despite 14-3-3 proteins being implicated in the control of the eukaryotic cell cycle, metabolism, cell signalling and survival, little is known about the global regulation or functions of the phosphorylation-dependent binding of 14-3-3s to diverse target proteins. We identified Arabidopsis cytosolic proteins that bound 14-3-3s in competition with a 14-3-3-binding phosphopeptide, including nitrate reductase, glyceraldehyde- 3-phosphate dehydrogenase, a calcium-dependent protein kinase, sucrose-phosphate synthase (SPS) and glutamyl-tRNA synthetase. Remarkably, in cells starved of sugars or fed with non-metabolizable glucose analogues, all 14-3-3 binding was lost and the target proteins were selectively cleaved into proteolytic fragments. 14-3-3 binding reappeared after several hours of re-feeding with sugars. Starvation-induced degradation was blocked by 5-amino imidazole-4-carboxamide riboside (which is converted to an AMP-mimetic) or the protease inhibitor MG132 (Cbz-leu-leu-leucinal). Extracts of sugar-starved (but not sugar-fed) Arabidopsis cells contained an ATP-independent, MG132-sensitive, neutral protease that cleaved Arabidopsis SPS, and the mammalian 14-3-3-regulated transcription factor, FKHR. Cleavage of SPS and phosphorylated FKHR in vitro was blocked by binding to 14-3-3s. The finding that 14-3-3s participate in a nutrient-sensing pathway controlling cleavage of many targets may underlie the effects of these proteins on plant development.
Department of Surgery, Karolinska Hospital and Institute, Stockholm, Sweden.
In severe catabolic states, such as burn injury, sepsis and accidental injury, a state of marked insulin resistance is encountered. Insulin resistance is also present after elective surgical treatment, more pronounced with increasingly greater magnitude of operation performed. Results of recent animal experiments have shown that even short periods of food deprivation, reducing carbohydrate reserves, alter responses to stress. This notion resulted in our questioning the rationale of carbohydrate depletion associated with overnight preoperative fasting. Twelve patients undergoing elective open cholecystectomy were randomly given no infusion (control group) or 5 milligrams per kilogram per minute of glucose infusion (glucose group) during preoperative overnight fasting. Insulin sensitivity (M value, milligram per kilogram per minute) was determined using the hyperinsulinemic normoglycemic clamp (plasma insulin level, 65 microunits per milliliter and blood glucose level, 4.5 millimoles per liter) before and the first postoperative day. Preoperative insulin sensitivity was similar in the two groups. Postoperatively, M values decreased by 55 +/- 3 percent (control group) and by 32 +/- 4 percent (glucose group)(p < 0.01). Plasma levels of insulin, c-peptide, glucagon, growth hormone, catecholamines and cortisol in connection with clamps were similar in both groups preoperatively and postoperatively. The present results indicate that active preoperative carbohydrate preservation may improve postoperative metabolism because postoperative occurrence of insulin resistance was reduced with preoperative glucose infusion.
Department of Neurology, Karolinska Hospital, Stockholm, Sweden.
A comparison of serum carbohydrate-deficient transferrin with other biological markers of excessive drinking.
National Institute of Forensic Toxicology, Oslo, Norway.
In a study of suggested biological markers of excessive drinking, serum carbohydrate-deficient transferrin (CDT) was compared with serum activities of alanine aminotransferase, alkaline phosphatase, amylase, aspartate aminotransferase and gamma glutamyltransferase; serum concentrations of high-density lipoprotein cholesterol; and erythrocyte mean cellular volume. Analytical data were studied in relation to self-reported alcohol consumption during the latest month for the 69 participating subjects. CDT was found to be the most sensitive and most specific marker of excessive drinking, and was also found to be the best marker for monitoring abstinence under treatment of alcoholics.
Station de Physiologie Végétale, Institut National de la Recherche Agronomique, Villenave d'Ornon, France.
Differential hybridization of a cDNA library constructed with poly(A)+ mRNA from 24 h starved maize (Zea mays L.) root tips, resulted in the isolation of a cDNA (called pZSS1) that was highly induced during glucose deprivation. The nucleotide sequence analysis of the full-length cDNA allowed its identification by comparison with sequence data bases. The 586 amino acid sequence encoded by pZSS1 was shown to be about 60% identical to sequences of asparagine synthetases (EC 220.127.116.11) from Asparagus officinalis, Pisum sativum, Arabidopsis thaliana and Brassica oleracea. Southern blot analysis of maize genomic DNA showed that asparagine synthetase may be encoded by at least two genes. The use of a specific probe for the 3' untranslated region of pZSS1 in Northern blot experiments, revealed that the isolated AS gene was essentially expressed in roots of maize seedlings. Time course analysis revealed that maximal expression of the gene corresponding to pZSS1 occurs between 18 and 24 h after the onset of the starvation treatment. The steady-state levels of transcripts in maize root tips were found to change under various incubation conditions. Exogenous supply of metabolizable sugars downregulated the gene expression, while carbohydrate deprivation or feeding with non-metabolizable sugars resulted in the induction of gene expression. In addition to carbohydrate deprivation, the effects of nitrogen metabolite supply and stress conditions indicate that gene expression might be under metabolic control in maize root tips. The intracellular nitrogen to carbon ratio might be an important factor for the regulation of asparagine synthetase gene expression.
Department of Pediatrics, University of Leuven, Belgium.
The carbohydrate-deficient glycoprotein syndromes are a recently individualized group of genetic multisystemic disorders. A predominant feature is a severe involvement of the central and peripheral nervous system resulting in psychomotor retardation, seizures, ataxia, and, mostly after infancy, stroke-like episodes. The hallmark biochemical feature is a carbohydrate deficiency in a large number of serum glycoproteins. Because coagulation factors and inhibitors are also glycoproteins, we performed a systematic study of these factors and inhibitors in nine patients with carbohydrate-deficient glycoprotein syndrome. All showed a decreased activity of factor XI and of the coagulation inhibitors antithrombin III and protein C. In five of seven patients more than 1 y old, there was also a (less pronounced) decrease of protein S and of heparin cofactor II. This combined coagulation inhibitor deficiency could explain the stroke-like episodes occurring in these children.
Multiple signaling pathways in gene expression during sugar starvation. Pharmacological analysis of din gene expression in suspension-cultured cells of Arabidopsis.
Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Hongo, Tokyo 113-0033, Japan. firstname.lastname@example.org
We have identified many dark-inducible (din) genes that are expressed in Arabidopsis leaves kept in the dark. In the present study we addressed the question of how plant cells sense the depletion of sugars, and how sugar starvation triggers din gene expression in suspension-cultured cells of Arabidopsis. Depletion of sucrose in the medium triggered marked accumulation of din transcripts. Suppression of din gene expression by 2-deoxy-Glc, and a non-suppressive effect exerted by 3-O-methyl-Glc, suggested that sugar-repressible expression of din genes is mediated through the phosphorylation of hexose by hexokinase, as exemplified in the repression of photosynthetic genes by sugars. We have further shown that the signaling triggered by sugar starvation involves protein phosphorylation and dephosphorylation events, and have provided the first evidence that multiple pathways of protein dephosphorylation exist in sugar starvation-induced gene expression. An inhibitor of serine/threonine protein kinase, K-252a, inhibited din gene expression in sugar-depleted cells. Okadaic acid, which may preferentially inhibit type 2A protein phosphatases over type 1, enhanced the transcript levels of all din genes, except din6 and din10, under sugar starvation. Conversely, a more potent inhibitor of type 1 and 2A protein phosphatases, calyculin A, increased transcripts from din2 and din9, but decreased those from other din genes, in sugar-depleted cells. On the other hand, calyculin A, but not okadaic acid, completely inhibited the gene expression of chlorophyll a/b-binding protein under sugar starvation. These results indicate that multiple signaling pathways, mediated by different types of protein phosphatases, regulate gene expression during sugar starvation.
Optimized determination of carbohydrate-deficient transferrin isoforms in serum by capillary zone electrophoresis.
Institute of Forensic Medicine, University of Verona, Italy. email@example.com
Carbohydrate deficient transferrin (CDT) is one of the most reliable markers of chronic alcohol abuse. It consists of a group of minor isoforms of human transferrin (the main iron transport serum protein) deficient in sialic acid groups (asialo, monosialo and disialo) with a pI > 5.7, while the main isotransferrin (tetrasialo) has a pI of 5.4. The aim of the present work was to develop a capillary electrophoretic method to determine CDT in serum, suitable for routine use as a confirmatory technique of the current screening methods based on immunoassays. Serum samples (0.5 mL) were saturated with iron by incubation with 10 mM FeCl3 (9 microL) and 500 mM NaHCO3 (12 microL) for 30 min, then diluted 1/10 in water and injected by positive pressure (0.5 psi for 10 s). Separation was performed with a capillary zone electrophoretic method using bare fused-silica capillaries (20 microm ID, 37 cm in length) and a buffer composed of 100 mM sodium tetraborate adjusted with boric acid to pH 8.3. Applied voltage was 10 kV and temperature 25 degrees C. Detection was by UV absorption at 200 nm wavelength. Under the described conditions, asialo-, monosialo-, disialo-, trisialo- and tetrasialo-transferrin were separated in human serum. The limit of detection (signal-to-noise ratio of 2) was about 0.3% for disialo-transferrin, and 0.4% of trisialo-transferrin, expressed as percentages of the terasialo-transferrin peak area. Relative standard deviations (RSD) of absolute migration times were < 1%, while RSD of relative migration times (on the basis of tetrasialo-transferrin) were < 0.1%. Intra-day and day-to-day peak quantitation precision studies showed RDS ranging from 4 to 9% and from 13 to 24% for disialo- and trisialo-transferrin, respectively. The results from 30 control subjects, including social drinkers, and 13 alcoholics showed disialo- and trisialo-transferrin significantly increased in patients by a factor of about 4.5 (P < 0.0001).