Formulating the alginate-polyornithine biocapsule for prolonged stability: evaluation of composition and manufacturing technique.

Alginate encapsulation is one of the most widely used techniques for introducing cell-based therapeutics into the body. Numerous encapsulation methodologies exist, utilizing a variety of alginates, purification technologies, and unique polycationic membrane components. The stability of a conventional alginate formulation encapsulated using a commercially available technique and apparatus has been characterized extensively. The current study employs an encapsulation protocol and ultra-pure alginate pioneered at the University of Perugia. The enhanced microcapsules were produced, characterized, and implanted into the brain, peritoneal cavity, and subcutaneous space of Long-Evans rats. After 14, 28, 60, 90, 120, and 180 or 215 days, capsules were explanted and the surface was analyzed using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Image analysis was carried out to measure changes in diameter and wall thickness. FTIR peak analysis and surface morphology from SEM indicated that the enhanced encapsulation technique and formulation produced a stable biocapsule capable of survival in all sites, including the harsh peritoneal environment, for at least 215 days. Preimplant analysis showed a marked increase in the structural integrity of the enhanced formulation with improved elasticity and burst strength compared with the baseline formulation, which remained stable for less than 60 days. The enhanced microcapsule composition showed advantages in physical strength and longevity, indicating that small changes in encapsulation methodologies and materials selection can dramatically impact the stability and longevity of alginate microcapsules and their contents.

Cystic fibrosis screening in the newborn.

A new technique of measuring stool enzyme activity on dry specimens of faeces from newborn children at 4-5 days of age has detected 3 cases of cystic fibrosis in the first 6000 tests. No known cases of cystic fibrosis have been missed. Additionally, one case of pancreatic achylia of at least 4 months' duration has been detected. It is proposed that the detection of cystic fibrosis by this technique is sufficiently practical to be acceptable as a worthwhile newborn screening programme. The screening test has been in use in Auckland for over a year and is now being set up in Hamilton, Wellington, and Dunedin (New Zealand), and Sydney (Australia).

The changing presentation of children with newly diagnosed type 1 diabetes mellitus.

Although it is known that the incidence of type 1 diabetes mellitus (DM) in childhood is progressively increasing, it is less clear whether the presentation of newly diagnosed DM is changing. The aim of this study was to establish whether any biochemical or clinical presentation parameters have altered over time. A retrospective study was performed comparing newly diagnosed children with DM in two 24 month time intervals, 8 yrs apart (1988-89 and 1995-96). Fifty-seven children were diagnosed with type 1 DM in 1988-89 and 70 children in 1995-96. At presentation, children born in the later cohort had a higher pH (p < 0.001) and lower serum glucose (p < 0.05). Although the frequency of diabetic ketoacidosis (DKA) was higher in the 1988/89 cohort (63% vs. 42% in 1995/96) the absolute number of children with DKA in each time interval was similar (33 subjects in 1988-89 vs. 30 subjects in 1995/96). Islet cell antibody (ICA) levels were very different between the two cohorts; higher antibody levels were found in the 1988/89 group (p < 0.01). DKA was also associated with higher ICA titres (p < 0.05). Hospital admission stay decreased from 6.5 DS to 3.4 DS over the 8-year period (p < 0.0001). At our institution, the presentation of children with type 1 DM is changing with many more children diagnosed before developing DKA. We speculate that a new environmental factor(s) may be responsible for the absolute increase in patients presenting without DKA, while older etiologies (both genetic and environmental) are responsible for the steady, unchanging number of patients with a more severe presentation. Greater awareness of diabetes in children is not the factor contributing to earlier diagnosis before DKA develops.