Association between fear of hypoglycemia and physical activity in youth with type 1 diabetes: The SEARCH for diabetes in youth study.

BACKGROUND: Youth with type 1 diabetes (T1D) are encouraged to participate in physical activity (PA). Studies have identified fear of hypoglycemia (FOH) as a barrier to participating in PA. OBJECTIVES: To examine (a) PA patterns in youth with T1D by age group and (b) the relationship between both parental and youth FOH and youth PA. METHODS: A cross-sectional analysis from the SEARCH cohort study visit of youth ages 10 to 17 years with T1D (n = 1129) was conducted. Linear regression models estimated the association between self-reported number of days of vigorous PA (VPA) and moderate PA (MPA) and both youth- and parent-reported FOH. Multivariable models were adjusted for age, sex, race, duration of T1D, HbA1c, use of continuous glucose monitoring (CGM), recent severe hypoglycemia, primary insulin regimen, and BMI. RESULTS: Participants were 52% female, had mean (sd) age 14.4 (4.2) years, diabetes duration 7.5 years (1.8), HbA1c 9.2% (1.7). Older youth were less likely to engage in VPA (P < .01), or sports teams (P < .01), but more likely to engage in MPA (P < .01). Higher youth FOH (behavior subscale) was associated with increased levels of VPA (ß (se) 0.30 (0.11), P = .01) but not significantly associated with MPA (P = .06). There was no statistically significant association between parental FOH and youth PA. CONCLUSIONS: In SEARCH participants with T1D, VPA, and team sports participation declined with age, while MPA increased. We observed that higher scores on the youth FOH behavioral subscale were associated with increased VPA levels, suggesting that FOH may be less of a barrier to PA than previously thought.

Improvements in cognition, mood and behaviour following commencement of continuous subcutaneous insulin infusion therapy in children with type 1 diabetes mellitus: a pilot study.

AIMS/HYPOTHESIS: Anecdotally, parents and teachers of children with type 1 diabetes mellitus report improvements in behaviour and learning following the commencement of continuous subcutaneous insulin infusion (CSII). This study aimed to investigate changes in cognition, mood and behaviour following commencement of CSII in children with type 1 diabetes. METHODS: Children (n = 32) with type 1 diabetes aged 6-16 years and starting CSII at two Australian centres underwent behavioural, cognitive and glycaemic assessments prior to the commencement of CSII and 6-8 weeks after its start. A comprehensive cognitive test battery was administered, comprising measures of intelligence, attention, processing speed and executive skills. Behaviour and mood were assessed using the Behaviour Assessment System for Children--Second Edition. Continuous glucose monitoring was performed over a 72 h period and HbA(1c) was measured at both time-points. RESULTS: After commencement of CSII, there were significant improvements in HbA(1c), a reduction in hyperglycaemia and blood glucose variation and an increase in normoglycaemia. Significant improvements were observed in perceptual reasoning, selective attention, divided attention, cognitive flexibility and working memory. Fewer mood-related symptoms were reported (parent, teacher and self-report) and fewer behavioural problems (parent reports) CONCLUSIONS/INTERPRETATION: In this uncontrolled pilot study, children with type 1 diabetes demonstrated significant improvements in measures of metabolic control, mood and behaviour and in some complex cognitive skills after commencing CSII therapy.

Collagenase in wound healing: effect of wound age and type.

Collagenase is believed to be important for cell migration and collagen remodeling during tissue repair and regeneration. We have investigated collagenase concentrations in different types of surgically inflicted wounds in pigs. Collagenase was extracted from tissue homogenates of wounds by heating to 60 degrees C for 6 min in 0.1 M CaCl2. The molecular weight of latent collagenase was about 52 kDa. Activated collagenase produced the characteristic 3/4 fragment of collagen. Collagenase was assayed by the use of radiolabeled telopeptide-free collagen. To detect maximal collagenase activity, extracts were reduced and alkylated to destroy inhibitors, then activated with aminophenylmercuric acetate. Sutured incisions showed peak collagenase content on postoperative day 1 and thereafter steadily declining concentrations. Granulation tissue from non-sutured large defect full-thickness wounds showed high collagenase content on postoperative day 5 and then a sharp decline to day 7 followed by a slowly declining curve to postoperative day 21. Partial-thickness wounds exhibited a different time course, with collagenase increasing to peak concentrations on postoperative days 3-5; however, a large proportion of the detected collagenase was due to the adherent scab. By day 7 collagenase concentrations approached the low concentrations of normal skin when epithelialization was complete and the scab rejected. In general, collagenase shows an early maximum and then declines with postoperative time, with the sharpest decline occurring when epithelialization is complete.

Purification and properties of a small latent matrix metalloproteinase of the rat uterus.

A small metalloproteinase that digests Azocoll was found in the uterus of the rat. Its activity increased to high levels during the postpartum period in parallel with the breakdown of the extracellular matrix exclusive of collagen (Sellers, A., and Woessner, J.F., Jr. (1980) Biochem. J. 189, 521-531). This enzyme has now been purified almost 7,000-fold to homogeneity from 12 g of tissue using molecular sieve chromatography, blue sepharose chromatography, and zinc-chelate chromatography. Gel electrophoresis with sodium dodecyl sulfate and dithiothreitol gives Mr = 28,000 for the latent form of the enzyme and Mr = 19,000 for the active form that arises spontaneously or by treatment with aminophenylmercuric acetate. The enzyme digests components of the extracellular matrix including gelatins of types I, III, IV, and V, fibronectin, and proteoglycan. It digests the alpha 2(I) chain of gelatin in preference to the alpha 1(I) chain and cleaves dinitrophenyl-Pro-Leu-Gly-Ile-Ala-Gly-Pro-D-Arg. It cleaves the B chain of insulin at two points: Ala14-Leu15 and Tyr16-Leu17. It has no action on collagens of types I, III, IV, or V at 26 degrees C and no action on elastin or phenylazo-Pro-Leu-Gly-Pro-D-Arg. The pH optimum is at pH 7 and the pI at 5.9. The enzyme requires zinc and calcium ions for activity; cobalt and strontium can partially replace these metal ions. The enzyme is not inhibited by low levels of phosphoramidon or Zincov. Its properties clearly distinguish it from collagenase, gelatinase (matrix metalloproteinase 2), and stromelysin (matrix metalloproteinase 3); it therefore constitutes a further member of the family of extracellular matrix metalloendopeptidases. The name matrix metalloproteinase 7 is proposed.