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- Wisniewski, N, et al.
(författare)
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Analyte flux through chronically implanted subcutaneous polyamide membranes differs in humans and rats
- 2002
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Ingår i: American journal of physiology. Endocrinology and metabolism. - : American Physiological Society. - 0193-1849 .- 1522-1555. ; 282:6, s. E1316-E1323
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Tidskriftsartikel (refereegranskat)abstract
- The rat is commonly used to evaluate physiological responses of subcutaneous tissue to implanted devices. In vivo longevity of various devices and the biocompatibility of biomaterials depend on how adjacent tissue interacts. How closely the rat model predicts the human response has not been well characterized. The objective of this study was to compare rat and human subcutaneous foreign body responses by monitoring the biochemical environment at a polymer-tissue interface over 8 days using microdialysis. Polyamide microdialysis probes were implanted subcutaneously in humans and rats ( n = 12). Daily microdialysis samples were analyzed for glucose, lactate, pyruvate, glycerol, and urea. Blood glucose was also monitored. Analyte concentrations differed significantly between rats and humans at the implant-tissue interface. There were also qualitative differences in the 8-day trends. For example, over 8 days, microdialysate glucose increased two- to fourfold in humans but decreased in rats ( P < 0.001). This study reveals profound physiological differences at material-tissue interfaces in rats and humans and highlights the need for caution when extrapolating subcutaneous rat biocompatibility data to humans.
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| 2. |
- Arnetz, L, et al.
(författare)
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Improved Insulin Sensitivity during Pioglitazone Treatment Is Associated with Changes in IGF-I and Cortisol Secretion in Type 2 Diabetes and Impaired Glucose Tolerance
- 2013
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Ingår i: ISRN endocrinology. - : Hindawi Limited. - 2090-4630 .- 2090-4649. ; 2013, s. 148497-
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Tidskriftsartikel (refereegranskat)abstract
- Background. Hypercortisolism and type 2 diabetes (T2D) share clinical characteristics. We examined pioglitazone's effects on the GH-IGF-I and HPA axes in men with varying glucose intolerance. Methods. 10 men with T2D and 10 with IGT received pioglitazone 30–45 mg for 12 weeks. OGTT with microdialysis in subcutaneous adipose tissue and 1 μg ACTH-stimulation test were performed before and after. Glucose, insulin, IGF-I, IGFBP1, and interstitial measurements were analyzed during the OGTT. Insulin sensitivity was estimated using HOMA-IR. Results. HOMA-IR improved in both groups. IGF-I was initially lower in T2D subjects () and increased during treatment ( to SD; ); no change was seen in IGT ( SD before and during treatment). Fasting glycerol decreased in T2D (), indicating reduced lipolysis. Fasting cortisol decreased in T2D ( to nmol/L; ) but increased in IGT ( to nmol/L; ). Peak cortisol was lower in T2D during treatment ( to , versus to nmol/L in IGT; ). Conclusions. Pioglitazone improved adipose tissue and liver insulin sensitivity in both groups. This may explain increased IGF-I in T2D. Pioglitazone affected cortisol levels in both groups but differently, suggesting different mechanisms for improving insulin sensitivity between T2D and IGT.
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