Physiology of the small bowel: a new approach using MRI and proposal for a new metric of function

Background

The mechanics of small bowel motility are extremely complex. Routine clinical access to small bowel has been restricted to radiological enteric contrast studies which have not contributed significantly to the understanding of small bowel physiology. Small bowel mechanics are understood within a framework of individual visible or measurable elements such as peristaltic wave formation, intra-luminal pressure gradients and transit times. There are no global measures of small bowel function that can be readily obtained in vivo in humans. Magnetic resonance imaging (MRI) is playing an increasingly important role in radiological diagnosis of small bowel disease and dynamic MRI offers the possibility of capturing small bowel movement in three-dimensional cinematic datasets. The metrics that are used to describe small bowel mechanics, typically anatomical measures in isolated segments, are not suited to analysing these large dynamic datasets. The proposal in this paper is to leave behind all previously described anatomical metrics and to describe anew the mechanics of small bowel movement in mathematical terms derived from changes in pixel intensity within dynamic MRI datasets so that global small bowel activity might be summarised in a single novel metric.

Hypothesis

The hypothesis of this paper is that global small bowel activity can be quantified by a new dynamic MR based metric.

Evaluation

A proposed strategy for evaluation includes a progression through feasibility, optimisation, reliability and validation studies. Thereafter normal volunteers would be required in order to define normal ranges for the new metric. These ranges would describe small bowel activity during fasting or after ingestion of fluids and standard meals. Mathematical modelling of the data could follow a two stage approach. The first stage could be to study segmentation or extraction techniques by which the small bowel activity could be isolated from MRI signal generated by the rest of the abdomen. The second stage would be to apply a number of data mining techniques that would identify significant features within the datasets.

Conclusion

If this approach proves to be a useful model for studying small bowel physiology in humans, it would afford significant new avenues of research and treatment particularly in areas such as enteric drug delivery, the ageing gut, and nutrition.     

Amyloid histology stain for rapid bacterial endospore imaging

Bacterial endospores are some of the most resilient forms of life known to us, with their persistent survival capability resulting from a complex and effective structural organization. The outer membrane of endospores is surrounded by the densely packed endospore coat and exosporium, containing amyloid or amyloid-like proteins. In fact, it is the impenetrable composition of the endospore coat and the exosporium that makes staining methodologies for endospore detection complex and challenging. Therefore, a plausible strategy for facile and expedient staining would be to target components of the protective surface layers of the endospores. Instead of targeting endogenous markers encapsulated in the spores, here we demonstrated staining of these dormant life entities that targets the amyloid domains, i.e., the very surface components that make the coats of these species impenetrable. Using an amyloid staining dye, thioflavin T (ThT), we examined this strategy. A short incubation of bacillus endospore suspensions with ThT, under ambient conditions, resulted in (i) an enhancement of the fluorescence of ThT and (ii) the accumulation of ThT in the endospores, affording fluorescence images with excellent contrast ratios. Fluorescence images revealed that ThT tends to accumulate in the surface regions of the endospores. The observed fluorescence enhancement and dye accumulation, coupled with the sensitivity of emission techniques, provide an effective and rapid means of staining endospores without the inconvenience of pre- or posttreatment of samples.     

Emergency Medical Service (EMS) systems in developed and developing countries

OBJECTIVES: To compare patient- and injury-related characteristics of trauma victims and pre-hospital trauma care systems among different developed and developing countries. METHOD: We collated de-identified patient-level data from national or local trauma registries in Australia, Austria, Canada, Greece, Germany, Iran, Mexico, New Zealand, the Netherlands, the United Kingdom and the United States. Patient and injury-related characteristics of trauma victims with injury severity score (ISS) >15 and the pre-hospital trauma care provided to these patients were compared among different countries. RESULTS: A total of 30,339 subjects from one or several regions in 11 countries were included in this analysis. Austria (51%), Germany (41%) and Australia (30%) reported the highest proportion of air ambulance use. Monterrey, Mexico (median 10.1min) and Montreal, Canada (median 16.1min) reported the shortest and Germany (median: 30min) and Austria (median: 26min) reported the longest scene time. Use of intravenous fluid therapy among advanced EMS systems without physicians as pre-hospital care providers, varied from 30% (in the Netherlands) to 55% (in the US). The corresponding percentages in advanced EMS systems with physicians actively involved in pre-hospital trauma care, excluding Montreal in Canada, ranged from 63% (in London, in the UK) to 75% in Germany and Austria. Austria and Germany also reported the highest percentage of pre-hospital intubation (61% and 56%, respectively). CONCLUSION: This study provides an early look at international variability in patient mix, process of care, and performance of different pre-hospital trauma care systems worldwide. International efforts should be devoted to developing a minimum standard data set for trauma patients.     

Validation of Gastrointestinal Quality of Life Index in Swedish for Assessing the Impact of Gallstones on Health-Related Quality of Life

Objective:  The aim of the present study was to validate a Swedish translation of the Gastrointestinal Quality of Life Index (GIQLI) questionnaire in patients with gallstone disease.
Methods:  Sensitivity to change, internal consistency, and test–retest stability were tested in 187 consecutive patients who underwent planned cholecystectomy. Construct validity was assessed by comparing the GIQLI score with the bodily pain scale of SF-36 and four single-item questions in a separate group of 104 patients.
Results:  A significant increase in all five domains as well as in the overall GIQLI score 6 months after surgery (all P  < 0.05) was seen. All five domains correlated significantly with other measures of gallstone-related symptoms except one single-item question. Intraclass correlations ranged from 0.62 to 0.87. Cronbach's alpha ranged from 0.77 to 0.89.
Conclusion:  The Swedish translation of GIQLI has a high validity and reliability for assessing the impact of gallstones on quality of life.     

Correlation of PET standard uptake value and CT window-level thresholds for target delineation in CT-based radiation treatment planning

PURPOSE: To develop standardized correlates of [18F]fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) standard uptake value (SUV) to computed tomography (CT)-based window and levels. METHODS AND MATERIALS: Nineteen patients with non-small-cell lung cancer who underwent imaging with positron emission tomography (PET) and CT were selected. A method of standardizing SUV within CT planning software was developed. A scale factor, determined by a sensitivity calibration of the PET scanner, converts voxel counts to activity per gram in tissue, allowing SUVs to be correlated to CT window and levels. A method of limiting interobserver variations was devised to enhance "edges" of regions of interest based on SUV thresholds. The difference in gross tumor volumes (GTVs) based on CT, PET SUV >or= 2.5, and regions of 40% maximum SUV were analyzed. RESULTS: The mean SUV was 9.3. Mean GTV volumes were 253 cc for CT, 221 cc for SUV >or= 2.5, and 97 cc for SUV40%Max. Average volume difference was -259% between >or=2.5 SUV and CT and -162% between SUV40%Max and CT. Percent difference between GTV >or= 2.5 SUV and SUV40%Max remained constant beyond SUV > 7. For SUVs 4-6, best correlation among SUV thresholds occurred at volumes near 90 cc. Mean percent change from GTVs contoured according to CT (GTV CT) was -260% for GTV2.5 and -162% for GTV40%Max. Using the SUV40%Max threshold resulted in a significant alteration of volume in 98% of patients, while the SUV2.5 threshold resulted in an alteration of volume in 58% of patients. CONCLUSIONS: Our method of correlating SUV to W/L thresholds permits accurate displaying of SUV in coregistered PET/CT studies. The optimal SUV thresholds to contour GTV depend on maximum tumor SUV and volume. Best correlation occurs with SUVs >6 and small volumes <100 cc. At SUVs >7, differences between the SUV threshold filters remain constant. Because of variability in volumes obtained by using SUV40%Max, we recommend using SUV >or= 2.5 for radiotherapy planning in non-small-cell lung cancer.     

Heterotopic autotransplantation of vitrified mouse ovary

Purpose  

The aim of this study was to investigate the survival and development of premature follicles and oocytes from a vitrified-transplanted ovary in a murine experimental model.     

Effect of pulsed electromagnetic fields on maturation of regenerate bone in a rabbit limb lengthening model

To study the effect of applying pulsed electromagnetic fields (PEMF) during the consolidation phase of limb lengthening, a mid‐tibial osteotomy was performed in 18 adult New Zealand White rabbits and an external fixator was applied anteromedially. Animals were randomly assigned to treatment and control groups. After a 7‐day latency period, the tibiae were distracted 0.5 mm every 12 h for 10 days. The treatment group received a 20‐day course of PEMF for 60 min daily, coinciding with initiation of the consolidation phase. The control group received sham PEMF. Radiographs were performed weekly after distraction. Animals were euthanized 3 weeks after the end of distraction. Radiographic analysis revealed no significant difference in regenerate callus area between treatment and control tibiae immediately after distraction, at 1 week, 2 weeks, or 3 weeks after distraction ( p = 0.71, 0.22, 0.44, and 0.50, respectively). There was also no significant difference in percent callus mineralization ( p = 0.96, 0.69, 0.99, and 0.99, respectively). There was no significant difference between groups with respect to structural stiffness ( p = 0.80) or maximal torque to failure ( p = 0.62). However, there was a significant positive difference in mineral apposition rate between groups during the interval 1–2 weeks post‐distraction ( p < 0.05). This difference was no longer evident by the interval 2–3 weeks post‐distraction. While PEMF applied during the consolidation phase of limb lengthening did not appear to have a positive effect on bone regenerate, it increased osteoblastic activity in the cortical bone adjacent to the distraction site. Since the same PEMF signal was reported to be beneficial in the rabbit distraction osteogenesis when applied during distraction phase and consolidation phase, application of PEMF in the early phase may be more effective. Further work is necessary to determine optimal timing of the PEMF stimulation during distraction osteogenesis. © 2005 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res     

Stabilisierung des dorsalen Beckenrings mit eingeschobener Platte

OBJECTIVE: Minimally invasive stabilization of the posterior pelvic ring in type C injuries. INDICATIONS: Unstable type C injuries of the pelvic ring, uni- or bilateral. - Transsymphyseal-transsacral instability. - Transpubic-transsacral instability. - Transsymphyseal-transsacroiliac instability. - Transpubic-transsacroiliac instability. CONTRAINDICATIONS: Fractures in childhood. Comminuted fractures of the ilium. Patients with skin and soft tissues in a poor condition and/or local infection. Sacral fractures with a neurologic deficit are not a contraindication because they can be decompressed by distraction and stabilized in a neutral position by plate fixation. SURGICAL TECHNIQUE: Nut-shaped osteotomy of the posterior superior iliac spine bilaterally through two short, vertical skin incisions. Tunneling through the muscles of the back to the opposite side. Length measurement for a 4.5-mm pelvic reconstruction plate. The plate is bent by about 70 degrees over the fourth lateral hole. Slide-insertion of the plate and bending of the free plate end for close fit. Cancellous bone screws are inserted into the plate holes. Refixation of the osteotomized bone fragments over the plate with small-fragment, cancellous bone screws. RESULTS: 34 patients with an average age of 42.6 years were treated according to the described method from 1998 to 2005; 18 were polytraumatized. The anterior pelvic ring was also stabilized by surgery in 28 patients for eleven of whom it was the first intervention in a two-stage procedure. 25 patients were available for clinical and radiologic follow-up at 17 months, on average. The plain radiographs after 1 year showed a very good outcome in 16 patients (maximal displacement of the posterior pelvic ring < 5 mm) and a good outcome in eight patients (displacement of 5-10 mm). In two patients there was loss of reduction in the 1st postoperative year despite a very good reduction result immediately postoperatively (dislocation < 5 mm), whereby the dislocation for one patient was < 10 mm on the final radiograph and 19 mm for the other. One patient presented with a late infection 11 weeks postoperatively that healed after implant removal and wound debridement. In two other patients, prominent screw heads, which were used for refixation of the osteotomized posterior superior iliac spine, had to be removed under local anesthesia in the 10th postoperative week. The further course for these two patients was uneventful. In one patient the implants were retrieved in the 5th postoperative month because the patient complained of internal hot and cold sensations although the soft tissue was not irritated. The plates were removed in six other cases after the fracture/instability had healed, i. e., after 9-12 months, on average; in all other cases the implants were left in situ.     

Comparison of blood concentrations of 1,3-butadiene and butadiene epoxides in mice and rats exposed to 1,3-butadiene by inhalation

1,3–Butadiene (BD), an important commodity chemical usedin the production of synthetic rubber, is carcinogenic in B6C3F1mice and Sprague-Dawley rats, raising concern for potentialcarcinogenicity in humans. Mice are more sensitive than ratsto the carcinogenic effects of BD. Metabolic activation of BDto form the putative DNAreactive metabolites, butadiene monoxide(BMO) and butadiene diepoxide (BDE), is mediated by cytochromeP450. Detoxication of the epoxides occurs by glutathione Stransferase-catalyzedconjugation with glutathione and hydrolysis by epoxide hydrolase.Species differences in metabolic activation and detoxicationmost likely contribute to the difference in carcinogenic potencyof BD by modulating the circulating blood levels of the epoxides.This study measured the in vivo concentrations of BD, BMO andBDE in the blood of male Sprague-Dawley rats and B6C3F1 miceduring and following 6 h nose-only exposure to inhaled BD at62.5, 625 or 1250 p.p.m. BD. Blood samples for BD and BMO (     

Survival after hip fracture

Although it is known that overall mortality is increased after hip fracture, the influence of hip fracture risk factors on the subsequent mortality and cause of death has not been well studied. The objective of this study was to establish the survival after hip fracture in women and to assess the impact of comorbidity on mortality. We identified a complete population-based set of 2,245 incident hip fracture cases and 4,035 randomly selected population-based controls among women 50–81 years old in Sweden and followed these subjects for an average of 5 years through the Swedish National Inpatient and Cause-of-Death Registers. Information on factors related to hip fracture was obtained through linkage to hospital discharge data and through a mailed questionnaire. We studied excess mortality of hip fracture patients compared to controls using survival curves and proportional hazard regression models. During follow-up, 896 hip fracture patients (40%) and 516 (13%) controls died. The relative risk (RR) of death, adjusted for age and previous hospitalization for serious disease, was 2.3 (95% CI 2.0–2.5). Although the highest mortality risks were in the 1st 6 months post-fracture, RRs for fractures versus controls were increased for at least 6 years. Increased mortality was apparent both in those with evidence of comorbidity and those without. Hip fracture patients have a substantially increased risk of death that persists for at least 6 years post-fracture. The relative excess mortality is independent of comorbidity and known hip fracture risk factors.The authors represent the Swedish Hip Fracture Study Group, whose members include Akke Alberts, John A. Baron, Thomas Dolk, Bahman Y. Farahmand, Olof Johnell, Lena Lindén, Sverker Ljunghall, Karl Michaëlsson, Gunnar Brobert, Karl-Göran Thorngren, Mats Thorslund, Carl Zetterberg and Lena Zidén.