The factors that influence colonic transit time in healthy humans are not yet clearly defined. The aim of this study was therefore to determine (a) if there are differences in colonic transit time between men and women and (b) if age, female hormonal status or smoking habits are associated with alterations in these parameters. Colonic transit time was measured in 164 asymptomatic subjects (80 males, 84 females) by a radio-opaque marker technique with one single plain abdominal X-ray. Colonic transit time was significantly shorter in men than in women (30 +/- 2 vs. 42 +/- 3 h, P < 0.05). Colonic transit time in non-smoking males was significantly shorter compared with smoking males (26 +/- 2 vs. 40 +/- 5 h, P < 0.05). In females only height and menstrual cycle influenced colonic transit times. We conclude that gender and smoking habits should be considered when studying colonic transit time in health and disease.

In patients with hepatitis C virus (HCV)-related advanced fibrosis/cirrhosis, 30% of sustained HCV clearance has been reported with pegylated interferon alpha-2a (PEG-IFN) alone, but the efficacy and tolerability of the PEG-IFN/ribavirin (RBV) combination remain poorly defined. A total of 124 treatment-naïve patients with biopsy proved HCV-related advanced fibrosis/cirrhosis (Ishak score F4-F6, Child-Pugh score < or =7) were randomized to 48 weeks of PEG-IFN (180 microg sc weekly) and standard dose of RBV (1000/1200 mg po daily, STD) or PEG-IFN (180 microg sc weekly) and low-dose of RBV (600/800 mg po daily, LOW). Sustained virologic response (SVR) rates with PEG-IFN/STD RBV (52%) were higher--albeit not significantly--than that with PEG-IFN/LOW RBV (38%, P = 0.153). In multivariate analysis, genotype 2/3 and a baseline platelet count > or =150 x 10(9)/L were independently associated with SVR. The likelihood of SVR was < 7% if viraemia had not declined by > or =2 log or to undetectable levels after 12 weeks. Nine adverse events in the STD RBV and 15 in the LOW RBV group were classified as severe (including two deaths); dose reductions for intolerance were required in 78% and 57% (P = 0.013), and treatment was terminated early in 23% and 27% of patients (P = n.s.). The benefit/risk ratio of treating compensated HCV-cirrhotics with STD PEG-IFN/RBV is favourable.

The aim of the present study was to develop a breath test to measure liquid gastric emptying rates that would be without radiation exposure and applicable to field testing. Four different test meals were investigated: a glucose meal, an amino acid meal, a fat meal, and a mixed meal (Ensure). The test meals were labeled with two markers, [13C]acetate and PEG-4000 (polyethylene glycol 4000). Gastric emptying rates were measured simultaneously by both breath test and the double-indicator technique in eight healthy male subjects. The appearance of 13CO2 in the breath closely reflected gastric emptying of the four test meals as measured by the double-indicator technique. It is concluded that the [13C]acetate breath test is a reliable, noninvasive test to measure gastric emptying rates of liquid test meals.