Detection of small bowel tumors by videocapsule endoscopy in patients with acromegaly

The prevalence of colon polyposis andmalignancies is increased in acromegalic patients as compared to the general population. An epidemiological study suggests a high prevalence also of small bowel (SB) tumors that nowadays may be detected by videocapsule endoscopy (VCE). The aim of the study was to assess the prevalence of SB neoplasms using VCE in acromegalic patients in comparison to control subjects and to correlate it with cancer risk factors and acromegaly-related parameters. Eighteen acromegalic patients (6 males and 12 females, age+/-SD: 54+/-10 yr), 5 cured after surgery (followed by radiotherapy in 3 cases) and 13 on pharmacological treatment were enrolled, and 36 sex- and age-matched non-acromegalic subjects served as a control group. Cancer risk factors, duration of acromegaly, GH and IGF-I levels, IGF binding protein 3 and IGF-II concentrations, metabolic parameters, tumor markers, colonic lesions by total colonoscopy, and SB lesions by VCE were investigated. VCE images suggestive of SB lesions were detected in 5/36 controls [14%, 4 described as gastrointestinal stromal nodular tumors (GIST), and 1 as polyp] and in 5/18 acromegalic patients [28%, 2 GIST and 3 polyps]. In acromegaly, the calculated relative risk for all SB lesions was 1.69 [95%confidence interval (CI): 0.78-3.65], while the relative risk for SB polyps was 2.50 (95% CI: 1.23-5.07). The effective duration of active disease was longer in patients with positive than in those with negative VCE (112+/-89 vs 49+/-40 months, p=0.06). In conclusion, these preliminary results suggest that acromegalic patients might have a high risk of SB polyp development. VCE might be a useful adjunctive diagnostic tool in acromegaly.

Perceptual sensitivity and response bias during rectal distension in patients with irritable bowel syndrome

Patients with irritable bowel syndrome (IBS) report an increased frequency of sensations during rectal distension in comparison with healthy subjects. This alteration might be due to a psychological response bias leading patients to over report their sensations. The aim of this study was to measure perceptual sensitivity and response bias during rectal distension in healthy subjects and IBS patients using the sensory decision theory (SDT). Thirteen healthy subjects and 22 IBS patients underwent five rectal distensions up to 100 mL, five up to 200 mL and five sham distensions. They were asked to identify the distension by means of an electronic marker. Perceptual sensitivity and response bias were calculated according to the SDT. The patients identified a more 100 mL distensions than the healthy subjects (P = 0.02), whereas there was no difference in the number of identified 200 mL and sham distensions between the two groups. The perceptual sensitivity of IBS patients was significantly greater during 100 mL (P = 0.01), but not during 200 mL distensions. The response bias was not significantly different between the two groups. These data suggest that the increased frequency of sensations reported by IBS patients is not due to a psychological response bias.

Effect of rectal distension on abdominal girth

It has been postulated that a viscerosomatic reflex activated by gut distension and inhibiting abdominal wall muscle tone may be one of the mechanisms underlying functional abdominal distension. Any demonstration of such a reflex has to take into account the fact that gut distension may increase abdominal girth as a result of volume displacement. As biomechanical and sensory rectal responses vary at different rates of rectal distension, we hypothesized that different rates of rectal distension might reveal different changes in abdominal girth. Abdominal girth was continuously recorded in 14 healthy subjects using a previously validated extensometer. The rectal distensions were made in a randomized order at rates of 100 mL min(-1) or 10 mL min(-1) up to 150 mL, and sham distensions were used as controls. An increase in abdominal girth was observed at the end of both distensions (P </= 0.008): it was greater after the fast (1.1 +/- 0.5 mm) than after the slow distension (0.8 +/- 0.7 mm), but this difference was not statistically significant (P = 0.2). In conclusion, we were unable to demonstrate the existence of a viscerosomatic reflex activated by gut distension under our experimental conditions.

Abdominal distension after colonic lactulose fermentation recorded by a new extensometer

Colonic lactulose fermentation induces bloating, but whether it also causes abdominal distension is not known. The aim of this study was to assess the effect of colonic lactulose fermentation on abdominal girth using a new extensometer. We recorded abdominal girth in 24 healthy subjects by means of an extensometer that measures the phase shift of an ultrasound wave propagating in a tube encircling the abdomen. The recordings were continuously made for 3 h after the ingestion of 100 mL of tap water with (16 subjects) or without (eight subjects) 10 g of lactulose. Every 10 min, H2 in the breath was analysed and the intensity of bloating was recorded. Bloating was never reported after water ingestion, whereas it was reported by 10 subjects after lactulose ingestion (P = 0.002). The mean +/- SD changes in abdominal girth in comparison with resting conditions were statistically significant after lactulose ingestion (3 +/- 2.9 mm; P = 0.002) but not after water ingestion (-0.2 +/- 2.7 mm; P = 0.82). The area under the curve of the changes in abdominal girth after lactulose were significantly greater than after water ingestion (P = 0.03). In conclusion, colonic lactulose fermentation induces bloating and abdominal distension. The new extensometer is useful for continuously recording changes in abdominal girth.

Influence of caloric intake on gastric emptying of solids assessed by 13C-octanoic acid breath test

BACKGROUND

The 13C-octanoic breath test (13C-OBT), a recently developed technique to evaluate gastric emptying of solids, has been validated in comparison to scintigraphy with low caloric meals (250 kcal). However, there is consensus that for clinical studies total caloric load should be in excess of 300 kcal, but studies comparing 13C-OBT results after low and medium caloric meals are lacking.

METHODS

Ten healthy subjects were given a 250-kcal and a 550-kcal meal in randomized order. Gastric emptying was assessed simultaneously by ultrasonography and 13C-OBT. Breath samples were taken according to both classic (21 samples over 5 h) and simplified (11 samples) schedules.

RESULTS

Increasing the meal energy content resulted in significantly longer half emptying time (T(1/2)) estimates by both ultrasonography (P < 0.01, Wilcoxon test) and 13C-OBT (P < 0.05). T(1/2) estimates by the two methods significantly correlated for both the 250 (r(s) = 0.733, P = 0.018) and the 550 (r(s) = 0.637, P = 0.035) kcal meal. However, differences between T(1/2) estimates by 13C-OBT and ultrasonography were greater after the 550- than the 250-kcal meal (median 172.5 versus 76.5 min, P < 0.05). Interindividual variability was also 2-fold greater for indexes estimated by 13C-OBT with the 550-kcal meal compared with the 250-kcal meal. For both meals 13C-OBT yielded similar results with the classic and simplified schedules.

CONCLUSIONS

In healthy subjects caloric intake is a major determinant of gastric emptying rate. However, after a medium caloric meal 13C-OBT shows some inaccuracy, which raises questions about its routine clinical application. Nevertheless, when using 13C-OBT one must take into account that the simplified schedule is just as effective as the classic one, and is far lower in cost.

HCV genotypes in Northern Italy: a survey of 1368 histologically proven chronic hepatitis C patients

BACKGROUND/AIMS

Hepatitis C virus (HCV) easily undergoes genomic changes, thus accounting for the presence of different genotypes, with different geographic distributions and different outcomes of chronic hepatitis. Type 1b is frequently found in advanced diseases; however, since this genotype is the most prevalent in older patients, the association with advanced age and severity of the disease is confounding. The aim of this study was to assess changes in the prevalence of HCV genotypes by surveying a large population of chronic hepatitis C patients in Northern Italy, and to assess if the high prevalence of genotype 1b in older patients with advanced diseases simply reflects the duration of HCV infection, rather than intrinsic biological properties of HCV.

METHODS

We studied 1368 HCV-RNA positive patients, with histologically proven chronic hepatitis. Drug addiction, blood transfusions and sporadically acquired infections represented the risk factors.

RESULTS

Genotype 1b, the most prevalent isolate, and genotype 2a were associated with older age, cirrhosis, sporadically-acquired infections and blood transfusion, while types 1a, 3a, and 4 were associated with younger age, chronic persistent hepatitis and drug addiction. Patients with a history of transfusions were divided into four groups depending on the period of transfusion. The prevalence of genotype 1b decreased with time. Type 3a appeared only after 1979.

CONCLUSION

The severity of chronic hepatitis C could be related more to the duration of the infection rather than to the intrinsic pathogenicity of HCV genotypes.