Importance of blinding and expectations in opioid-induced constipation: evidence from a randomized controlled trial

Objectives Previous studies have found little association between objective measures and the subjective experience of opioid-induced constipation. The subjective experience of opioid-induced constipation may be influenced by treatment expectations. While most trials control for treatment expectations through blinding, success rate is generally low. This study aimed to explore the association between objective measures and the subjective experience of opioid-induced constipation, while considering blinding success and treatment expectations, and other psychological factors. Methods Data from a randomized, double-blinded, placebo-controlled crossover trial including 21 healthy male participants was analyzed. Participants received either placebo, tapentadol, or oxycodone (in equipotent doses) for 14 days. They were assessed on objective and subjective measures of opioid-induced constipation (gastrointestinal transit time and the Patient Assessment of Constipation-Symptoms questionnaire, respectively), treatment guesses to indicate blinding success, and psychological factors. Results There was a strong association between objective and subjective measures of opioid-induced constipation when participants were treated with oxycodone (r=0.676, p=0.006). Furthermore, participants were able to guess that they received active treatment when treated with oxycodone (p<0.001), suggesting that treatment expectations may have influenced the subjective experience of symptoms. Finally, patterns of moderate associations between opioid-induced constipation and other psychological factors emerged, although none reached significance (p>0.05). Conclusions Results indicate that treatment expectations could play an important role in the subjective experience of opioid-induced constipation, and support the importance of assessing blinding success in study trials. Besides expectations, other psychological factors may be associated with opioid-induced constipation.

Corn? When did I eat corn? Gastrointestinal transit time in health science students

The objective of this study was to determine gastrointestinal transit time in first-year health science students with a laboratory practical exercise conducted in two cohorts (classes of 2018 and 2019) of first-year health sciences students at the Health Science Campus in Windhoek, Namibia. All first-year health science students undertaking the Physiology course were invited to take part in the laboratory exercise. The primary outcome was the measurement of gastrointestinal transit time from the amount of time taken for ingested whole-kernel sweetcorn to be eliminated, which was calculated as the time period between ingestion of corn and the time of corn first seen in the stool and the time corn was last seen in the stool. The secondary outcome was an association between emotional irritability and/or anxiety and gastrointestinal transit time. The study analyzed responses of 175 students, who reported a median transit time of 29 (1–99) h. There was no difference in gastrointestinal transit time between male and female students. Likewise, there was no difference in the duration of the corn in the bowel between male and female students. Students who reported being worried and irritable during the exercise had more bowel movements before they saw corn in their stool and had slower transit times, respectively. A wider range of transit time was reported in a group of young, healthy students compared with previous studies in the literature. There were no differences between male and female student bowel activity. Anxiety did impact the bowel activity of the participants.

Adults with Prader–Willi syndrome exhibit a unique microbiota profile

Objective Adults with Prader–Willi syndrome (PWS) require less energy intake to maintain body weight than the general adult population. This, combined with their altered gastrointestinal transit time, may impact microbiota composition. The aim of the study was to determine if the fecal microbiota composition of adults with PWS differed from non-affected adults. Using usual diet/non-interventional samples, fecal microbiota composition was analyzed using 16S rRNA gene amplicon sequencing and data from adults with PWS were merged with four other adult cohorts that differed by geographical location and age. QIIME 2™ sample-classifier, machine learning algorithms were used to cross-train the samples and predict from which dataset the taxonomic profiles belong. Taxa that most distinguished between all datasets were extracted and a visual inspection of the R library PiratePlots was performed to select the taxa that differed in abundance specific to PWS. Results Fecal microbiota composition of adults with PWS showed low Blautia and enhanced RF39 (phyla Tenericutes), Ruminococcaceae, Alistipes, Erysipelotrichacaea, Parabacteriodes and Odoribacter. Higher abundance of Tenericutes, in particular, may be a signature characteristic of the PWS microbiota although its relationship, if any, to metabolic health is not yet known.

Oral drug dosing following bariatric surgery - General concepts and specific dosing advices

Bariatric or weight-loss surgery is a popular option for weight reduction. Depending on the surgical procedure, gastric changes like decreased transit time and volume and increased pH, decreased absorption surface in the small intestine, decreased exposure to bile acids and enterohepatic circulation, and decreased gastrointestinal transit time may be expected. In the years after bariatric surgery, patients will also substantially lose weight. As a result of these changes, the absorption, distribution, metabolism, and/or elimination of drugs may be altered. The purpose of this article is to report the general influence of bariatric surgery on oral drug absorption, and to provide guidance for dosing of commonly used or high-risk drugs in this special population. Upon oral drug administration, the time to maximum concentration is often earlier and this concentration may be higher with less consistent effects on trough concentrations and exposure. Additionally, prescription of liquid formulations to bariatric patients is supported by some reports, even though the high sugar load of these suspensions may be of concern. Studies on extended release medications result in an unaltered exposure for a substantial number of drugs. Also, studies evaluating the influence of timing after surgery show dynamic absorption profiles. Although for this group a specific advice can be proposed for many drugs, we conclude that there is insufficient evidence for general advices for oral drug therapy after bariatric surgery implying that a risk assessment on a case-by-case basis is required for each drug.

Anatomic-radiographic aspects and gastrointestinal transit time in boa constrictor amarali stull, 1932 (Squamata, Boidae)

ABSTRACT The goal of this study was to describe the gastrointestinal transit technique in the Boa constrictor amarali. For that purpose, we obtained simple radiographic images of seven serpents, subsequently administering a 25mL/kg dose of barium sulfate and establishing a radiographic sequence at the following times: 5 minutes; 1, 2, 3, 6, 9, 24, 48, 72 and 96 hours, extending to 120 and 126 hours for one animal. The mean esophageal transit was 26.71±19.48 hours; the mean gastric filling time was 28.57±27.22 minutes and the emptying time was 60±12 hours; the mean filling time of the contrast medium in the small intestine was 3±2.16 hours and the emptying time was 97±15.65 hours. We also obtained the mean filling time of the large intestine, which was 40±11.31 hours. We found that the mean passage time of the contrast medium through the cranial gastrointestinal tract - until the complete elimination of barium sulfate from the small intestine -was 97±15.65 hours. In addition to determining the gastrointestinal transit time, the technique used allowed for the morphological identification of the alimentary canal.

Digestibility and gastrointestinal transit of Ulva fasciata seaweed meal in tilapia (Oreochromis niloticus) juveniles: basis for the inclusion of a sustainable ingredient in aquafeeds

The seaweed Ulva fasciata has many features favorable to integrated multi-trophic aquaculture (IMTA). It is efficient at biofiltering, shows high biomass production, and is rich in many nutrients useful in aquatic animal diets. We evaluated the digestibility of the seaweed meal of U. fasciata produced in IMTA and its effects on gastrointestinal transit time in tilapia (Oreochromis niloticus) juveniles. Juveniles (6.30 ± 1.80 g initial weight, and 5.5 ± 0.61 cm initial length) were cultivated in six tanks (50 individuals per tank) in a closed recirculating aquaculture system. The digestibility of Ulva meal was 57.92 ± 5.21% for dry material, 78.59 ± 1.91% for protein, and 69.87 ± 3.72% for energy. The inclusion of 10% seaweed meal did not alter the gastrointestinal transit time in tilapia juveniles as compared to controls. The earliest colored feces were observed four hours after first feeding in both treatments (feed diets with [10%] and without seaweed); all fecal material was colored after ten hours. The digestibility of seaweed meal was satisfactory for dry material, protein, and gross energy, and the inclusion of 10% of that meal did not change gastrointestinal transit time - indicating that the inclusion of 10% seaweed meal in tilapia diet is safe and without any nutritional use losses.

Exaggerated postprandial GLP-1 secretion following esophagectomy is not associated with gastric emptying and intestinal transit

Summary Esophagectomy causes postprandial symptoms associated with an exaggerated postprandial gut hormone response. This study aimed to compare the gastrointestinal transit time of patients 1 year after esophagectomy with unoperated controls, including its relation to satiety gut hormone release. In this cross-sectional study, consecutive, disease-free patients after esophagectomy with pyloroplasty were compared with unoperated control subjects to assess gastric emptying (GE) and cecal arrival time (CAT). Serial plasma samples were collected before, and for 300 minutes after, a mixed-meal challenge. Body composition was assessed, and symptom scores were calculated. Eleven patients 1 year post-esophagectomy (age: 62.6 ± 9.8, male: 82%) did not show a significantly different GE pattern compared with 10 control subjects (P = 0.245). Rather, patients could be categorized bimodally as exhibiting either rapid or slow GE relative to controls. Those with rapid GE trended toward a higher postprandial symptom burden (P = 0.084) without higher postprandial glucagon-like peptide-1 (GLP-1) secretion (P = 0.931). CAT was significantly shorter after esophagectomy (P = 0.043) but was not significantly associated with GE, GLP-1 secretion, or symptom burden. Neither early nutrient delivery to the proximal small intestine nor to the colon explains the exaggerated postprandial GLP-1 response after esophagectomy. GE varies significantly in these patients despite consistent pyloric management.