Morphoanatomical aspects of the starting material for the improvement of pineapple cryopreservation by the droplet-vitrification technique.

Cryopreservation of pineapple shoot tips has been established from various protocols, including droplet vitrification. Thus, this work aimed to evaluate the morphoanatomical conditions of the starting material over different times (30, 45 and 60 days) of culture before freezing and its correlation with the survival percentage of the cryopreserved shoot tips. Four accessions, Ananas comosus var. comosus (BGA-009); var. bracteatus (BGA-119); var. parguazensis (BGA-376), var. erectifolius (BGA-750) from the Pineapple Active Germplasm Bank (BGA Pineapple) and two hybrids from the Embrapa Genetic Breeding Program, FIB-ROX1 (var. bracteatus X var. erectifolius) and FIB-ROX2 ( var. erectifolius X var. bracteatus), recently introduced in the field from in vitro storage, were used. Histological sections before freezing and the percentages of survival after freezing were obtained taking into account the different times of cultivation of the donor plants. The results showed a significative interaction between genotypes (accessions and hybrids) and the culture period. The accessions BGA-009 and BGA-119 showed the highest survival rates, with 95% and 90% respectively for the 30-day culture time. Different results were obtained for each genotype, showing the need for improvements in the standardization of starting material, which would allow better repeatability of the protocol.

U500 regular insulin use in insulin-resistant type 2 diabetic veteran patients.

OBJECTIVE: To evaluate the use of U500 regular insulin therapy in insulin-resistant patients with type 2 diabetes mellitus who were previously treated with high-dosage U100 insulin regimens. METHODS: At a large Veterans Affairs medical center, a retrospective chart review was performed of all patients whose U100 insulin regimens were converted to U500 regular insulin regimens using a protocol to ensure patient safety. Patients were followed up for longer than 6 months. Data reviewed included total daily dosage of insulin before and after regimen conversion and changes in hemoglobin A1c, body weight, lipids, and episodes of severe hypoglycemia. RESULTS: Fifty-three patients met inclusion criteria. Average hemoglobin A1c level on U100 insulin regimens was 9.1 ± 1.7%, which decreased to 8.1 ± 1.3% (P<.001) after an average of 20 months (range, 6-52 months) on U500 insulin. The total daily insulin dosage at study end was not significantly greater on U500 (415 ± 166 units/day) than on U100 insulin (391 ± 120 units/day) (P = .34). Body weight did not change significantly (134 ± 29 kg vs 136 ± 30 kg, P = .18). There was a 20-mg/dL decrease in total cholesterol (P = .014). Triglyceride values decreased by 97 mg/dL (P = .005). Eight episodes of severe hypoglycemia were documented in patients treated with U500 insulin, but this was similar to the incidence in these same patients while treated with U100 insulin. CONCLUSION: We conclude that U500 insulin can be safely and effectively used in insulin-resistant patients with type 2 diabetes followed up at a large Veterans Affairs medical center using a protocol that ensures patients are thoroughly educated and carefully monitored.