Characterization and shelf stability of sweetened condensed milk formulated with different sucrose substitutes during storage.

Sweetened condensed milk (SCM) is a value-added milk product with extended shelf life and high levels of nutrition. The high level of sucrose may lead to health problems. Many studies have focused on the reduction of sucrose but seldomly on different combination of sugar substitutes. This study aims to find an ideal sucrose substitution through physiochemical, microbiological and sensory properties of SCM under different storage times. The results demonstrated that substitution with 20% trehalose, 5% lactulose and 15% erythritol resulted in similar sensory and color as control group. The volatile flavor analysis showed that substitution with 30% trehalose, 5% lactulose and 5% polyols was the most similar and hexanoic acid was the symbolistic flavor. Sucrose replacement increased the antibacterial effect and Staphylococcus, Penicillium, Apiotrichum and Candida were widely present. Substitution with 30% trehalose, 5% lactulose and 5% polyols resulted in the most similar water activity, texture, aroma and microbial diversity.

Application of methane and hydrogen-based breath test in the study of gestational diabetes mellitus and intestinal microbes.

OBJECTIVE: Gestational diabetes mellitus (GDM) is a common complication of pregnancy. The purpose of this study was to compare the incidence of small intestinal bacterial overgrowth (SIBO) in patients with GDM and the control group by methane and hydrogen lactulose breath test (LBT), and to explore its relationship with inflammation, vitamins, and the outcomes of maternal and child. METHODS: LBT was detected in 220 GDM patients, 160 pregnancy control patients and 160 pre-pregnancy control patients. The fasting blood glucose, white blood cells, vitamin A, D, E, neonatal weight, neonatal blood glucose and so on were compared and analyzed. RESULTS: There was no statistical significance in the general data of the three groups. The proportion of abdominal distension in the GDM group was higher than that in the other two groups (P < 0.001). The positive rates of SIBO + in GDM group, gestational control group and pre-pregnancy control group were 54.55%, 27.50% and 14.38%, respectively. The average abundance of hydrogen and methane in GDM group was significantly higher than that in control group at each time point. In the GDM group, SIBO + subjects had higher levels of fasting blood glucose, glycoglycated hemoglobin, C-reactive protein, neonatal weight, and lower levels of vitamin D and neonatal blood glucose (P < 0.001). CONCLUSION: Patients with GDM have a high incidence of SIBO, and SIBO may further increase their blood glucose by affecting inflammatory response and vitamin level, and even affect the outcome of mother and child.

Diagnosing Small Intestinal Bacterial Overgrowth: A Comparison of Lactulose Breath Tests to Small Bowel Aspirates.

BACKGROUND: Duodenal aspiration (DA) and lactulose breath tests (LBT) are commonly performed to diagnose small intestinal bacterial overgrowth (SIBO). There are no data directly comparing these tests. AIMS: To investigate the agreement between DA and LBT for the diagnosis of SIBO. METHODS: A retrospective cohort study of adult patients who underwent a LBT and a DA at a tertiary care center over 9 years was assembled. LBT was considered positive if the hydrogen baseline or peak change measurement was ≥ 20 ppm, and/or if the methane baseline or peak change was ≥ 10 ppm. DA was considered positive if > 100,000 cfu/mL of gram-negative flora was identified on culture, and contaminated if > 100,000 cfu/mL of gram-positive flora was identified. RESULTS: A total of 106 patients were evaluated; 81 (76.4%) were female; the mean age was 53.4 ± 15.9 years. 21 patients (19.8%) had evidence of contamination on DA. 14 (16.5%) patients had a positive DA result. Patients with diabetes mellitus and those with PPI use were more likely to have a positive DA (94.4% vs. 71.4%, p = 0.007; 62% vs. 28.6%, p = 0.021, respectively). 33 (31.1%) patients had a positive LBT. Patients with a history of small bowel resection were more likely to have a positive LBT (12.1% vs. 1.4%, p = 0.016). DA and LBT results agreed in 54 patients (63.5%; kappa = - 0.02), indicating poor agreement. CONCLUSIONS: The agreement between LBT and DA in evaluation for SIBO was poor. LBT may be favorable to DA, as LBT is safer, cheaper, and less likely to yield a contaminant result.

Simultaneous assessment of intestinal permeability and lactase activity in human-milk-fed preterm infants by sugar absorption test: Clinical implementation and analytical method.

BACKGROUND & AIMS: Experimental (nutritional) interventions in preterm infants frequently focus on intestinal maturation, as improving tolerance to enteral nutrition is a major goal. Intestinal permeability and lactase activity serve as markers for intestinal maturation. We aimed to develop a protocol for the simultaneous assessment of both markers in human-milk-fed preterm infants by a sugar absorption test. In addition, we developed a new gas chromatography-mass spectrometry (GC-MS) method for the analysis of lactulose, lactose, and mannitol in urine and milk collected during the sugar absorption test. METHODS: The sugar absorption test was performed on days 4, 7, and 14 postpartum in 12 preterm infants (gestational age of 26-32 weeks). Human milk was collected, pooled, and divided into equal portions to provide a stable lactose intake for 24 h. Urine was collected in the last 6 h of this 24 h period, after administration of a bolus test sugar solution. Samples were analyzed by GC-MS after derivatization by oxime formation combined with acetylation. RESULTS: The GC-MS method was validated and used for the accurate measurement of lactulose, lactose, and mannitol concentrations. The urinary lactulose/mannitol ratio declined with time, suggesting a decreased intestinal permeability. The urine-to-milk-lactulose/lactose ratio increased as a result of increased lactase activity with time. CONCLUSIONS: The developed protocol for simultaneous assessment of intestinal permeability and lactase activity can be used to monitor the effect of experimental (nutritional) interventions in human-milk-fed preterm infants. Urine and milk samples obtained during the sugar absorption test can be accurately analyzed by GC-MS.

Small intestinal bacterial overgrowth among patients with celiac disease unresponsive to a gluten free diet.

BACKGROUND/AIMS: Little is known about the relationship between small intestinal bacterial overgrowth (SIBO) and celiac disease (CeD) in patients who are unresponsive to a gluten-free diet (GFD). This study aimed to determine the SIBO prevalence in patients with CeD who are unresponsive to a GFD. MATERIALS AND METHODS: We conducted a case-control study from July 2012 to September 2014. We included 32 patients with CeD who were unresponsive to a GFD and 52 healthy age- and sex-matched controls. Demographic, clinical, and laboratory data were obtained from patients' medical records. Antitissue transglutaminase antibody determined by enzyme-linked immunosorbent assay was recorded, and lactulose hydrogen breath test (LHBT) was used to detect SIBO in all participants. Microbiological analysis, including jejunal aspirates obtained using upper endoscopy, was performed for only 20 patients with CeD. RESULTS: A total of 10 (31%) of 32 patients with CeD and 4 (7.7%) of 52 controls tested positive for LHBT, with a statistically significant difference (p=0.007). Of 20 cultures, 3 (15%) were positive with no statistically significant correlation between the cultures and LHBT (p=0.05). In a subgroup analysis of children who were 18 years old or younger, 7/24 (29.2%) patients with CeD had a positive LHBT compared with 3/32 (9.4%) controls, but this difference was not statistically significant (p=0.08). CONCLUSION: The prevalence of SIBO was 31% in unresponsive patients with CeD according to LHBT and 15% in the quantitative culture of the jejunal aspirate, which is comparable with the published Western literature.

Short-course Rifaximin therapy efficacy and lactulose hydrogen breath test in Chinese patients with diarrhea-predominant irritable bowel syndrome.

BACKGROUND: Gut microbiota alterations including small intestinal bacterial overgrowth (SIBO) might play a role in pathogenesis of irritable bowel syndrome (IBS). Rifaximin could effectively and safely improve IBS symptoms. The aim of this study was to investigate the effect of rifaximin on Gastrointestinal (GI) symptoms, quality of life (QOL) and SIBO eradication in Chinese IBS-D patients. METHODS: This study included 78 IBS-D patients defined by the Rome IV criteria. Patients received 400 mg rifaximin twice daily for 2 weeks and 10-week follow-up. GI symptoms were assessed at week 0, 2, 4, 8 and 12. QOL and lactulose hydrogen breath test (LHBT) results were estimated at week 0 and 4. RESULTS: All participants showed significant improvements in GI symptom subdomains after rifaximin treatment (all P < 0.05), which could maintain at least 10 weeks of follow-up. Additionally, QOL scores were increased with concomitant improvement of clinical symptoms (all P < 0.05). The 45 rifaximin-responsive patients (57.7%) achieved significantly greater GI-symptom improvement than non-responders (all P < 0.05). No GI symptoms were associated with SIBO (all P > 0.05). SIBO normalization after rifaximin treatment measured by LHBT was found in 44.4% (20/45) of patients with SIBO before treatment. CONCLUSION: A short course (2 weeks) of rifaximin improved GI symptoms and QOL in Chinese IBS-D patients whether they had SIBO or not. However, the efficacy of rifaximin could not be explained by the successful eradication of SIBO. Further studies on the therapeutic mechanisms of rifaximin in IBS are urgently needed.

The Effect of Ursodeoxycholic Acid on Small Intestinal Bacterial Overgrowth in Patients with Functional Dyspepsia: A Pilot Randomized Controlled Trial.

Functional dyspepsia (FD) is associated with small intestinal bacterial overgrowth (SIBO). Several animal studies have reported that ursodeoxycholic acid (UDCA) has antibacterial and anti-inflammatory effects in the intestine. We hypothesized that UDCA may be effective against dyspeptic symptoms and SIBO in patients with FD. We conducted this randomized controlled trial to investigate the effects of UDCA in FD patients with SIBO. Twenty-four patients diagnosed with FD and SIBO based on lactulose breath test (LBT) were randomly assigned to either a UDCA treatment group or an untreated group. The treatment group received 100 mg of UDCA three times per day for two months; the untreated group was monitored for two months without intervention. After two months in both groups, we reevaluated LBT and FD symptoms using the Nepean dyspepsia index-K. FD symptoms in the UDCA-treated group were significantly reduced after two months compared with baseline and FD symptom scores between the UDCA-treated and untreated groups showed statistically significant differences after two months. In addition, the total methane gas levels for 90 minutes in LBT were significantly decreased after two months compared with baseline in the UDCA-treated group. In this preliminary exploratory study, we found that two months of UDCA treatment resulted in FD symptom improvement and reduced methane values during 90 minutes on the LBT, suggesting that methane-producing SIBO were associated with symptoms of dyspepsia and that UDCA was helpful in these patients. These findings need to be validated via large-scale controlled and well-designed studies.

Rapid HPLC method for monitoring of lactulose production with a high yield.

An HPLC method suitable for rapid monitoring of lactulose production by isomerization from lactose was developed. The separation of lactose and lactulose under hydrophilic interaction liquid chromatography (HILIC) mode was achieved with resolution 1.5 within 5 min. Since isocratic elution was used, there is no extra time necessary for the column equilibration. Application of the method was illustrated on monitoring lactulose isomerization with catalysis of sodium hydroxide in the presence of sodium tetraborate at 70 °C (pH = 11). The conversion yield obtained for lactulose was 86%, and corresponding purity 76%. For the first time, a polyhydroxy stationary phase for separation of lactose and lactulose is reported.

Lactulose Breath Testing Can Be a Positive Predictor Before Weight Gain in Participants with Obesity Submitted to Roux-en-Y Gastric Bypass.

BACKGROUND: Small intestinal bacterial overgrowth (SIBO) is defined as the colonization of fermentative bacteria in the duodenum and jejunum. The alteration of digestive anatomy promoted by bariatric surgery may be a pre-disposing factor for SIBO. In this context, the prevalence of SIBO in participants undergoing bariatric surgery using Roux-en-Y gastric bypass (BGYR) was evaluated. METHODS: Participants, both sexes, older than 18 years, were those who (a) had bariatric surgery by the BGYR technique at least 1 year before the data collection and (b) did not use antibiotics recently. The SIBO diagnosis was established through the hydrogen breath test (H2BT), with intake of lactulose and serial collection of breath samples over 2 h. A test with ≥ 12-point elevation over the basal sample at 60 min after substrate intake was deemed positive. RESULTS: A total of 18 participants (14 females (77.8%)) were enrolled with a mean age of 50.5 years (range, 23 to 79 years). The interval between surgery and data collection ranged from 5 to 20 years (mean, 11.2 years). The mean preoperative body mass index (BMI) was 44.6 kg/m2 (range, 36.7-56.2 kg/m2). The H2RT with lactulose was positive for SIBO in seven (six female) participants. The participants with negative test measured trough H2BT with lactulose had a lower mean BMI of 28.69 kg/m2, in comparison with the positive group, which presented a mean BMI of 33.04 kg/m2 (p value = 0.041). CONCLUSION: Our data point to a high prevalence of SIBO (38.8%) in patients undergoing BGYR with a value in accordance with the literature. Moreover, the differences in BMI between negative and positive groups by H2BT with lactulose evidenced a weight gain relapse in participants with SIBO.

Analysis of Genetic Association of Intestinal Permeability in Healthy First-degree Relatives of Patients with Crohn's Disease.

Excessive intestinal permeability or intestinal barrier dysfunction as measured by various assays has been observed in various diseases. However, little is known about the factors contributing to altered gut permeability in these diseases. Our objective was to determine the genetic determinants of altered gut permeability as measured by the lactulose mannitol fractional excretion ratio (LacMan ratio) in 1075 healthy first-degree relatives of patients with Crohn's disease (CD). In a targeted analysis of single nucleotide polymorphisms (SNPs) located in genes associated with intestinal barrier function related or not to inflammatory bowel disease, we did not find a significant association with intestinal permeability. In an untargeted genome-wide association analysis, the top 100 associations were located in 22 genomic loci, although they were not statistically significant after correction for multiple testing (raw P values [1.8 × 10-7 - 1.4 × 10-5]. The lowest P value was obtained for rs9616637 (22q13.33, C22orf34), for which the minor allele A was associated with a decreased LacMan ratio. These results suggest that host genetic background has limited contribution toward intestinal permeability. Despite this, our study is currently the largest of its kind assessing gut permeability in vivo. It remains possible that smaller genetic effect sizes on LacMan ratio are not detectable in this sized cohort. Larger studies are warranted to identify the potential genetic contribution to intestinal permeability.

Zinc Absorption and Endogenous Fecal Zinc Losses in Bangladeshi Toddlers at Risk for Environmental Enteric Dysfunction.

OBJECTIVES: Environmental enteric dysfunction (EED) impairs zinc absorption from food, and zinc deficiency may contribute to the poor growth associated with EED. We examined zinc absorption from a standardized aqueous zinc dose, and habitual daily endogenous fecal zinc excretion (EFZ) and compared these outcomes between children grouped by the lactulose to mannitol ratio (L:M). METHODS: Bangladeshi toddlers (18-24 months) with low (<0.09) and high (≥0.09) L:M were administered isotope-labeled 3 mg aqueous zinc in the fasted state. Fractional absorption of zinc (FAZ) and EFZ were measured by dual stable isotope tracer method and an isotope dilution method, respectively. Secondary aims included examining relationships of biomarkers of systemic and intestinal inflammation and gut function with FAZ and EFZ. RESULTS: Forty children completed the study; nearly all had evidence of EED. No differences in zinc homeostasis measurements (mean ±â€ŠSD) were observed between high and low L:M groups: FAZ was 0.38 ±â€Š0.19 and 0.31 ±â€Š0.19, respectively; both figures were within estimated reference range. Means of EFZ were 0.73 ±â€Š0.27 and 0.76 ±â€Š0.20 mg/day for high and low L:M, respectively, and were 10% to 15% above estimated reference range. Regression analyses indicated that biomarkers of systemic inflammation were directly associated with increasing FAZ, consistent with increased gut permeability. Biomarkers of intestinal inflammation were negatively associated with EFZ, consistent with low-zinc intake and chronic deficiency. CONCLUSIONS: In these children at risk of EED, endogenous zinc losses were not markedly increased. Results suggest that efforts to improve zinc status in EED should focus on substantially improving zinc intakes.

Impact of Oral-Cecal Transit Time on the Interpretation of Lactulose Breath Tests After RYGB: a Personalized Approach to the Diagnosis of SIBO.

BACKGROUND: Traditionally, small intestinal bacterial overgrowth (SIBO) is diagnosed when there is an early peak in breath hydrogen or methane. Given unclear intestinal transit time in Roux-en-Y gastric bypass (RYGB) patients, it is unknown if the traditional approach at diagnosing SIBO is adequate in this patient population. AIM: To assess oral-cecal transit time (OCTT) and its impact on the interpretation of breath tests in the diagnosis of SIBO in patients with RYGB. METHODS: This study was a retrospective review of prospectively collected data on RYGB patients who underwent testing for SIBO using lactulose breath test (LBT) with or without small bowel follow-through (SBFT) to assess OCTT. Outcomes of SIBO test based on LBT alone versus LBT with OCTT were compared using a chi-squared test. RESULTS: Sixty-two of the 151 RYGB patients who underwent LBT underwent an additional SBFT to assess OCTT. Median OCTT was 60 min. Of these, 59.7% had OCTT shorter than 90 min. Based on LBT alone, 36/62 patients (58.1%) were classified as positive SIBO. When LBT results were combined with OCTT, 26/36 patients (72.2%) had hydrogen or methane rise within OCTT, suggesting 27.8% false positive rate. Patients with true positive SIBO based on LBT and OCTT had a higher response rate to antibiotics compared to those with false positive SIBO (78.3% vs. 33.3%, p = 0.03). CONCLUSION: A personalized approach of combining LBT with SBFT to assess OCTT may improve the accuracy of SIBO testing and enhance clinical outcomes in patients with RYGB.

Lactulose determination in UHT milk by CZE-UV with indirect detection.

Lactulose is not found naturally in milk, but it has been detected in small quantities in heated dairy products. It can therefore be used as an indicator of the severity of heat treatment for dairy products. This study proposes an alternative method for lactulose quantification in milk using capillary zone electrophoresis with ultraviolet detection (CZE-UV). The investigation used several Brazilian UHT milk samples, and various sample pretreatment methods and injection conditions were considered. Optimal separation results were achieved using Carrez clarification solutions. Low detection and quantification limits were obtained, and good precision and high recovery rates indicated the applicability of the method for analysis of milk. Due to matrix effects, single-point standard addition was used for lactulose quantification. High lactulose concentrations (>1000 mg L-1) suggested that recirculation may have occurred during milk processing. The findings demonstrate that the CZE-UV method is a viable alternative for quality process control.

Functional cream cheese supplemented with Bifidobacterium animalis subsp. lactis DSM 10140 and Lactobacillus reuteri DSM 20016 and prebiotics.

The aim of this study was to develop a functional fresh cream cheese with Bifidobacterium animalis subsp. lactis DSM 10140 or Lactobacillus reuteri DSM 20016 and prebiotics (inulin, FOS and lactulose). The research was divided into two steps: in vitro evaluation of the effects of prebiotic compounds; validation at laboratory level with production of functional cream mini-cheeses. Prebiotics showed a protective effect: B. animalis subsp. lactis DSM 10140 cultivability on Petri dishes was positively influenced by lactulose, whereas fructooligosaccharides (FOS) were the prebiotic compounds able to prolong Lb. reuteri DSM 20016 cultivability. At 30 °C, a prolongation of the death time (more than 300 days) was observed, while the controls showed death time values about 100 days. At 45 °C, death time values increased from 32.2 (control) to 33, 35, and 38 days in the samples added with FOS, inulin and lactulose, respectively. Lactulose and FOS were chosen to be added to cream mini-cheeses inoculated with B. animalis subsp. lactis DSM 10140 and Lb. reuteri DSM 20016, respectively; the proposed functional cream cheese resulted in a product with favourable conditions for the viability of both probiotics which maintained cultivable cells above the recommended level during 28 days of storage at 4 °C with good sensory characteristics.

The association between a positive lactulose methane breath test and rectocele in constipated patients

Objectives: Rectocele with constipation might be related to methane (CH4) producing intestinal bacteria. We investigated the breath CH4 levels and the clinical characteristics of colorectal motility in constipated patients with rectocele. Methods: A database of consecutive female outpatients was reviewed for the evaluation of constipation according to the Rome III criteria. The patients underwent the lactulose CH4 breath test (LMBT), colon marker study, anorectal manometry, defecography and bowel symptom questionnaire. The profiles of the lactulose breath test (LBT) in 33 patients with rectocele (with size ≥ 2 cm) and 26 patients with functional constipation (FC) were compared with the breath test results of 30 healthy control subjects. Results: The mean size of rectocele was 3.52 ± 1.06 cm. The rate of a positive LMBT (LMBT+) was significantly higher in patients with rectocele (33.3%) than in those with FC (23.1%) or healthy controls (6.7%) (p = 0.04). Breath CH4 concentration was positively correlated with rectosigmoid colon transit time in rectocele patients (γ = 0.481, p < 0.01). A maximum high pressure zone pressure > 155 mmHg was a significant independent factor of LMBT+ in rectocele patients (OR = 8.93, 95% CI = 1.14-71.4, p = 0.04). Conclusions: LMBT+ might be expected in constipated patients with rectocele. Moreover, increased rectosigmoid colonic transit or high anorectal pressure might be associated with CH4 breath levels. Breath CH4 could be an important therapeutic target for managing constipated patients with rectocele (AU)

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The association between a positive lactulose methane breath test and rectocele in constipated patients.

OBJECTIVES: Rectocele with constipation might be related to methane (CH4) producing intestinal bacteria. We investigated the breath CH4 levels and the clinical characteristics of colorectal motility in constipated patients with rectocele. METHODS: A database of consecutive female outpatients was reviewed for the evaluation of constipation according to the Rome III criteria. The patients underwent the lactulose CH4 breath test (LMBT), colon marker study, anorectal manometry, defecography and bowel symptom questionnaire. The profiles of the lactulose breath test (LBT) in 33 patients with rectocele (with size ≥ 2 cm) and 26 patients with functional constipation (FC) were compared with the breath test results of 30 healthy control subjects. RESULTS: The mean size of rectocele was 3.52 ± 1.06 cm. The rate of a positive LMBT (LMBT+) was significantly higher in patients with rectocele (33.3%) than in those with FC (23.1%) or healthy controls (6.7%) (p = 0.04). Breath CH4 concentration was positively correlated with rectosigmoid colon transit time in rectocele patients (γ = 0.481, p < 0.01). A maximum high pressure zone pressure > 155 mmHg was a significant independent factor of LMBT+ in rectocele patients (OR = 8.93, 95% CI = 1.14-71.4, p = 0.04). CONCLUSIONS: LMBT+ might be expected in constipated patients with rectocele. Moreover, increased rectosigmoid colonic transit or high anorectal pressure might be associated with CH4 breath levels. Breath CH4 could be an important therapeutic target for managing constipated patients with rectocele.

The relationship between small intestinal bacterial overgrowth and irritable bowel syndrome.

OBJECTIVE: To explore the relationship between small intestinal bacterial overgrowth (SIBO) and irritable bowel syndrome (IBS). PATIENTS AND METHODS: Fifty IBS patients in the hospital from January 2015 to December 2015 were assigned to the treatment group, and 50 healthy persons were assigned to the control group. Lactulose hydrogen and methane breath test were performed to measure the percentage of SIBO and oro-cecal transit time (OCTT) in treatment group and control group. These subjects were further assigned to negative SIBO group and positive SIBO group to analyze the scores of symptoms. RESULTS: The percentage of positive SIBO in the treatment group (72%, 36/50) was significantly higher (p<0.05) than the control group (38%, 19/50). The scores of symptoms on the episode of IBS were not significantly different between the positive SIBO subgroup and the negative SIBO subgroup. The scores of symptoms in breath test were not significantly different between the positive SIBO subgroup and the negative SIBO subgroup. The OCTT in the treatment group (69.34±1.27 min) was significantly lower (p<0.05) than the control group (85.16±1.75 min). The OCTT in the positive SIBO group (88.57±4.62 min) was significantly higher (p<0.05) than the control group (73.42±5.25 min). The results of lactulose hydrogen and methane breath test in the treatment group were positively correlated (r = 0.987, p<0.01). The results of lactulose hydrogen and methane breath test in the control group after oral administration of lactulose were also positively correlated (r = 0.736, p<0.01). CONCLUSIONS: SIBO was related to IBS and could prolong OCTT, yet not worsen IBS.

[The dietary features of diarrhea predominant irritable bowel syndrome patients with small intestinal bowel overgrowth].

Objective: To explore the diet features of diarrhea predominant irritable bowel syndrome (IBS-D) with small intestinal bacterial overgrowth (SIBO). Methods: IBS-D patients were enrolled in outpatient department of Peking University Third Hospital from March 2015 to April 2016. Healthy volunteers were recruited as controls (HC). All the subjects completed screening examinations, clinical and food investigation, and lactulose methane and hydrogen breath test (LMHBT). The high fat diet is defined as the daily total calories supplying from fat is more than 50%. Results: Eighty-eight IBS-D patients and 32 HC were finally enrolled. The positive rate of LMHBT in IBS-D was significantly higher than that of HC[39.8% (35/88) vs 12.5%(4/28), P=0.005]. The 28 HC with negative LMHBT were enrolled in the follow-up analysis. (1) The BMI of IBS-P (IBS-D with positive LMHBT) was significantly lower than IBS-N (IBS-D with negative LMHBT) [(21.57±0.54) vs (23.30±0.53)kg/m(2,) P=0.032]. IBS-D patients with SIBO had higher scores of abdominal pain assess. (2) The proportion of dietary protein and carbohydrate in IBS-D was significantly higher than that of HC (14.39% vs 12.22%, P=0.001; 53.94% vs 46.25%, P=0.003, respectively). The proportion of diet fat was significantly higher in IBS-P than IBS-N[(47.19±2.62)% vs (40.74±1.66)%, P=0.038]. (3) The baseline of breath methane in IBS-P was significantly higher than that of in IBS-N[(8.69±0.39) ×10(-6) vs (6.39±0.47) ×10(-6,) P=0.002]. IBS-D patients with high fat diet had higher LMHBT positive rate than that of non-high fat diet patients[54.2% (13/24) vs 17.2% (11/64), P=0.001]. Breath methane peak value was positively correlated with the fat proportion of diet (r=0.413, P=0.022). Conclusions: About 39.8% IBS-D patients diagnosed by Rome Ⅲ are combined with SIBO. SIBO may affect IBS-D patients' nutritional status. High fat diet might be one of the risk factors for IBS-D with SIBO. Proper diet structure might reduce the prevalence of IBS-D, especially for IBS-D with SIBO.

Design and application of a lactulose biosensor.

In this study the repressor of Escherichia coli lac operon, LacI, has been engineered for altered effector specificity. A LacI saturation mutagenesis library was subjected to Fluorescence Activated Cell Sorting (FACS) dual screening. Mutant LacI-L5 was selected and it is specifically induced by lactulose but not by other disaccharides tested (lactose, epilactose, maltose, sucrose, cellobiose and melibiose). LacI-L5 has been successfully used to construct a whole-cell lactulose biosensor which was then applied in directed evolution of cellobiose 2-epimerase (C2E) for elevated lactulose production. The mutant C2E enzyme with ~32-fold enhanced expression level was selected, demonstrating the high efficiency of the lactulose biosensor. LacI-L5 can also be used as a novel regulatory tool. This work explores the potential of engineering LacI for customized molecular biosensors which can be applied in practice.

Is Hydrogen Breath Test with Lactulose Feasible for Measuring Gastrocecal Transit in Critically Ill Children? Pilot Study about Modification of the Technique.

Introduction. Gastrocecal transit time (GCTT) can be measured by exhaled hydrogen after lactulose intake (lactulose-eH2 test). The objectives were to assess whether it is possible to carry out this test in critically ill children with and without mechanical ventilation (MV) and to analyze whether the results are consistent with clinical findings. Methods. Patients admitted to the Pediatric Intensive Care Unit (PICU) for more than 3 days were included. Those with gastrointestinal disease prior to admission were excluded. A modified technique to obtain eH2 from the ventilator tubes was performed. Results. Sixteen patients (37.5% boys) with a median age of 19 (5-86.5) months were included. Five patients (31.2%) were breathing spontaneously but lactulose-eH2 test could not be performed while it could be performed successfully in the 11 patients with MV. Seven patients (63.3%) did not show an eH2 peak. The other 4 showed a median time of 130 min (78.7-278.7 min) from lactulose intake to a 10 ppm eH2 peak. Children with an eH2 peak had intestinal movements earlier [6.5 (1.5-38.5) versus 44 (24-72) hours p = 0.545]. Conclusion. Although the designed adaption is useful for collecting breath samples, lactulose-eH2 test may not be useful for measuring GCTT in critically ill children.