[Examination of gastric emptying rate by means of 13C-octanoic acid breath test. Methods of the test for adults and results of the investigation of healthy volunteers].
ABSTRACT 13C-octanoic acid breath test (13C-OABT) is a simple, safe and non-invasive technique for measuring gastric emptying. However, the method has not been standardized yet. Aim of the study was to work up, introduce and evaluate our own method of the 13C-OABT for adults.
Ten healthy volunteers entered the study (5 men, 5 women, mean age 32 years, 50 % Helicobacter pylori positive). Standard test meals (with 100 mg 13C-sodium octanoate) were used three times within 3 weeks. The same solid meal (1,178 kJ) for Tests 1 and 2 contained scrambled egg (+ 3 g oil), white bread (40 g), butter (10 g) and distilled water (200 ml). Semi-solid meal (1,020 kJ) for Test 3 contained milk pudding (200 g) and distilled water (200 ml). Duplicate breath samples were obtained before and every 15 minutes after eating the test meal during 255 minutes. Altogether 1,080 breath samples were analysed twice (isotope ratio mass spectrometry, AP2003 Analytical Precision, UK). To assess the half-life of elimination (t1/2 E), we modelled the process of elimination with the incomplete gamma-function, which has a convenient form for the empiric plotting of breath test data. Mean t1/2E was 136+/-10 minutes (Test 1), 134+/-14 (Test 2) and 123+/-16 minutes (Test 3). Clinical reproducibility of 13C-OABT in particular persons was 98.2% (18 breath samples series), 90.8 % (15 samples) and 87.1% (9 breath samples series). There was a significant correlation between Test 1 and Test 2 results (r=0.887, p<0.0001). Mean difference of duplicate breath sample analysis was 1.460 % (in 540 pairs), mean baseline one-day analysis difference was 0.0982 (99.9274% accuracy). In healthy volunteers, normal range of t1/2E is 110-160 minutes for solids and 91-155 minutes for semisolid test meal. Using our own computed mean time of intermediate metabolism of 13C-octanoic acid (76.5+/-7.5 minutes), gastric emptying half-time is 33.5-83.5 minutes for solids and 14.5-78.5 minutes for semisolid test meal in healthy volunteers.
The 13C-OABT is accurate non-invasive method for gastric emptying measurement.
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ABSTRACT: Gastric emptying is frequently abnormal in patients with long-standing type 1 and type 2 diabetes mellitus. Symptoms commonly associated with disordered gastric emptying include nausea, vomiting, bloating and epigastric pain, while patients are also at risk of malnutrition, weight loss, impaired drug absorption, disordered glycaemic control and poor quality of life. Although often attributed to the presence of irreversible autonomic neuropathy, acute hyperglycaemia represents a potentially reversible cause of gastric dysfunction in diabetes. Scintigraphy represents the gold standard for measuring gastric emptying. The management of diabetic gastroparesis is less than optimal, partly because the pathogenesis has not been clearly defined. Treatment approaches include dietary modification and optimization of glycaemia, and the use of prokinetic drugs, while novel therapies such as gastric electrical stimulation are the subject of ongoing investigation.Drugs 02/2009; 69(8):971-86. DOI:10.2165/00003495-200969080-00003 · 4.13 Impact Factor
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ABSTRACT: In this work, insulin-loaded nanoparticles comprised of varying ratios of hyaluronic acid (HA) and chitosan (CS) were prepared using polyelectrolyte complexation and characterised. This generally lead to homogenous (polydispersity index generally below 0.2) and stable dispersions with surface potential being generally over |30| mV and particle size ranging from 120-300 nm. A chromatographic purification scheme was developed using a simple size-exclusion chromatography column and validated with excellent separation of nanoparticles and free insulin. A number of potentially suitable direct and indirect release study methods such as centrifugation, centrifugal filtration and dialysis were assessed with dialysis using a 100 kDa molecular weight cut off being deemed the most suitable of the methods tested. One species of nanoparticles, produced using 5:1 w/w (HA257/CS), showed sufficiently low release of insulin at clinically relevant timepoints with only 8% insulin release in SGF after 4 hours dialysis implying potential for shielding from proteolysis and targeted release. It was observed that the presence of nanoparticles significantly increased the rate of insulin permeation across the dialysis membrane. Though the data obtained through dialysis is not without some degree of error, the results are sufficient to show promise in the carrier system and support the undertaking of further investigation in to their suitability for use in a novel oral insulin formulation.12/2014, Degree: B.Sc.(Pharm.), Supervisor: Lidia Tajber