OBJECTIVE -The efficacy of the insulin analogs now available for multiple daily injection (MDI) and continuous subcutaneous insulin infusion (CSII) therapy in type 1 diabetes has not yet been established in pediatric patients. Our principal aim in this short-term study was to compare the efficacy of CSII to MDI with glargine in lowering HbA 1c levels in children and adolescents with type 1 diabetes.RESEARCH DESIGN AND METHODS -Thirty-two youth with type 1 diabetes (age 8 -21 years) were randomly assigned to receive either MDI treatment with once-daily glargine and premeal/snack insulin aspart or CSII with insulin aspart. Dose titration in both groups was based on home self-monitored blood glucose measurements and monthly HbA 1c . HbA 1c , total daily insulin dose (TDD), self-monitored blood glucose readings, and adverse events were compared after 16 weeks of therapy.RESULTS -While there was no significant change in the glargine group (HbA 1c 8.2% at baseline vs. 8.1% at 16 weeks), youth randomized to CSII had a sharp reduction in HbA 1c levels, from 8.1 to 7.2% after 16 weeks of therapy (P Ͻ 0.02 vs. baseline and Ͻ0.05 vs. glargine group). TDD was unchanged in the glargine group, but significantly dropped with CSII (1.4 units/kg at baseline vs. 0.9 units/kg at 16 weeks, P Ͻ 0.01). Both groups had similar basal doses and insulin-to-carbohydrate ratios. Fasting self-monitored blood glucose was similar in both groups, but lunch, dinner, and bedtime readings were significantly lower in the CSII group (P Ͻ 0.01).CONCLUSIONS -Lower HbA 1c and premeal glucose levels were more achievable in this short-term study with CSII than with glargine-based MDI treatment. CSII is an efficacious treatment to improve metabolic control in youth with type 1 diabetes. Diabetes Care 27:1554 -1558, 2004T he Diabetes Control and Complications Trial (1,2) demonstrated the importance of lowering HbA 1c levels as close to normal as possible. The urgency to achieve strict diabetes control has contributed to a sharp increase in the use of continuous subcutaneous insulin infusion (CSII) in children with type 1 diabetes. Reports from our program (3,4) and others (5-7) have demonstrated that CSII can lower HbA 1c levels and rates of severe hypoglycemia in youth with type 1 diabetes. However, these findings can be questioned because prepump injection regimens varied in intensity and in the types of insulins that were used. Moreover, only the recent study of Weintrob et al. (7) was a randomized controlled trial of CSII versus multiple daily injections (MDIs) using NPH insulin.With intermediate-acting insulins, there are considerable dose-to-dose variations in the amount of insulin that is administered and absorbed (8). Additionally, the peaking actions of these insulins make them less than ideal for basal insulin replacement (8). These limitations have been overcome by the introduction of glargine insulin, the first soluble insulin analog that has a flat and prolonged timeaction profile. A disadvantage of MDIs with glargine is the large number of i...
CSII is a durable and effective means of optimizing glycemic control in very young patients with type 1 diabetes and may be superior to multiple daily injections in minimizing the risk of severe hypoglycemia in this age group. Employment of paid caregivers does not preclude safe and effective use of CSII.
Root-knot nematodes are obligate plant parasites that alter plant cell growth and development by inducing the formation of giant cells for feeding. Nematodes inject secretions from their esophageal glands through their stylet and into plant cells to induce giant cell formation. Meloidogyne javanica chorismate mutase 1 (MjCM-1) is one such esophageal gland protein likely to be secreted from the nematode as giant cells form. MjCM-1 has two domains, an N-terminal chorismate mutase (CM) domain and a C-terminal region of unknown function. It is the N-terminal CM domain of the protein that is the predominant form produced in root-knot nematodes. Transgenic expression of MjCM-1 in soybean hairy roots results in a phenotype of reduced and aborted lateral roots. Histological studies demonstrate the absence of vascular tissue in hairy roots expressing MjCM-1. The phenotype of MjCM-1 expressed at low levels can be rescued by the addition of indole-3-acetic acid (IAA), indicating MjCM-1 overexpression reduces IAA biosynthesis. We propose MjCM-1 lowers IAA by causing a competition for chorismate, resulting in an alteration of chorismate-derived metabolites and, ultimately, in plant cell development. Therefore, we hypothesize that MjCM-1 is involved in allowing nematodes to establish a parasitic relationship with the host plant.
Root-knot nematodes (Meloidogynejavanica) are obligate sedentary endoparasites that must penetrate the host root to initiate their life cycle. Many enzymes are secreted by the nematode to facilitate host penetration; required enzymes may include pectate lyases and cellulases. Using differential screening, a class III pectate lyase, Mj-pel-1 (M. javanica pectate lyase 1), was cloned from a library enriched for esophageal gland genes. DNA gel blotting confirmed that the Mj-pel-1 gene was of nematode origin and a member of a small multigene family. In situ hybridization localized the expression of Mj-pel-1 to the basal cells of the esophageal glands, while immunolocalization detected the protein in the esophageal glands as well as on the exterior of the nematode, confirming that the protein is secreted. When MJ-PEL-1 was expressed in Pichia pastoris, the resulting protein was active. The pH optimum of MJ-PEL-1 was 10.0, and the enzyme was five times more active on pectate than on pectin. Like other class III pectate lyases, MJ-PEL-1 also displayed an absolute requirement for Ca2+. The root-knot nematode migrates through the middle lamella of the plant root; therefore, MJ-PEL-1 may be an important enzyme early in the infection process.
Leaves are reported to contain a secreted a-amylase that accumulates during senescence or after biotic or abiotic stress; however, a gene encoding this enzyme has not been described. Because a secreted amylase is isolated from plastidic starch, the function of this enzyme is difficult to predict, but circumstantial evidence suggests that it may degrade starch after cell death. The Arabidopsis thaliana genome contains three a-amylase genes, one of which, AMY1 (At4g25000), has a putative signal sequence suggesting that the protein may be secreted. Two independent T-DNA insertion mutants in AMY1 lacked an amylase band on starch zymograms, which was previously named 'A1'. Washed leaf protoplasts contained reduced A1 activity suggesting that the enzyme is secreted. Native AMY1, fused to a weakly fluorescent form of GFP, was sensitive to proteinase K infiltrated into leaf apoplastic spaces, while a cytosolic form of GFP was unaffected until cell breakage, confirming that the AMY1 protein is secreted. Amylase A1 was transcriptionally induced in senescing leaves and in leaves exposed to heat stress, treated with abscisic acid or infected with Pseudomonas syringae pv. tomato expressing avrRpm1. The A1 amylase was also extremely heat resistant and its expression was up-regulated in cpr5-2, an activated defence response mutant.
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