Pelvic Floor Rehabilitation After Rectal Cancer Surgery: A Multicenter Randomized Clinical Trial (FORCE Trial).

OBJECTIVE: To investigate the effects of PFR after LAR compared to usual care without PFR. SUMMARY OF BACKGROUND DATA: Functional complaints, including fecal incontinence, often occur after LAR for rectal cancer. Controversy exists about the effectiveness of PFR in improving such postoperative functional outcomes. METHODS: This was a multicenter, randomized controlled trial involving 17 Dutch centers. Patients after LAR for rectal cancer were randomly assigned (1:1) to usual care or PFR and stratified by sex and administration of neoadjuvant therapy. Selection was not based on severity of complaints at baseline. Baseline measurements were taken 3 months after surgery without temporary stoma construction or 6 weeks after stoma closure. The primary outcome measure was the change in Wexner incontinence scores 3 months after randomization. Secondary outcomes were fecal incontinence-related quality of life, colorectal-specific quality of life, and the LARS scores. RESULTS: Between October 2017 and March 2020, 128 patients were enrolled and 106 randomly assigned (PFR n = 51, control n = 55); 95 patients (PFR n = 44, control n = 51) were assessable for final analysis. PFR did not lead to larger changes in Wexner incontinence scores in nonselected patients after LAR compared to usual care [PFR: -2.3, 95% confidence interval (CI) -3.3 to -1.4, control: -1.3, 95% CI -2.2 to -0.4, P = 0.13]. However, PFR was associated with less urgency at follow-up (odds ratio 0.22, 95% CI 0.06-0.86). Patients without near-complete incontinence reported larger Wexner score improvements after PFR (PFR: -2.1, 95% CI -3.1 to -1.1, control: -0.7, 95% CI -1.6 to 0.2, P = 0.045). For patients with at least moderate incontinence PFR resulted in relevant improvements in all fecal incontinence-related quality of life domains, while the control group deteriorated. These improvements were even larger when patients with near-complete incontinence were excluded. No serious adverse PFR-related events occurred. CONCLUSION: No benefit was found of PFR in all patients but several subgroups were identified that did benefit from PFR, such as patients with urgency or with at least moderate incontinence and no near-complete incontinence. A selective referral policy (65%-85% of all patients) is suggested to improve postoperative functional outcomes for patients after LAR for rectal cancer. TRIAL REGISTRATION: Netherlands Trial Registration, NTR5469, registered on 3 September 2015.

Pelvic floor rehabilitation to improve functional outcome and quality of life after surgery for rectal cancer: study protocol for a randomized controlled trial (FORCE trial).

BACKGROUND: After low anterior resection (LAR), up to 90% of patients develop anorectal dysfunction. Especially fecal incontinence has a major impact on the physical, psychological, social, and emotional functioning of the patient but also on the Dutch National Healthcare budget with more than €2000 spent per patient per year. No standardized treatment is available to help these patients. Common treatment nowadays is focused on symptom relief, consisting of lifestyle advices and pharmacotherapy with bulking agents or antidiarrheal medication. Another possibility is pelvic floor rehabilitation (PFR), which is one of the most important treatments for fecal incontinence in general, with success rates of 50-80%. No strong evidence is available for the use of PFR after LAR. This study aims to prove a beneficial effect of PFR on fecal incontinence, quality of life, and costs in rectal cancer patients after sphincter-saving surgery compared to standard treatment. METHODS: The FORCE trial is a multicenter, two-armed, randomized clinical trial. All patients that underwent LAR are recruited from the participating hospitals and randomized for either standard treatment or a standardized PFR program. A total of 128 patients should be randomized. Optimal blinding is not possible. Stratification will be done in variable blocks (gender and additional radiotherapy). The primary endpoint is the Wexner incontinence score; secondary endpoints are health-related and fecal-incontinence-related QoL and cost-effectiveness. Baseline measurements take place before randomization. The primary endpoint is measured 3 months after the start of the intervention, with a 1-year follow-up for sustainability research purposes. DISCUSSION: The results of this study may substantially improve postoperative care for patients with fecal incontinence or anorectal dysfunction after LAR. This section provides insight in the decisions that were made in the organization of this trial. TRIAL REGISTRATION: Netherlands Trial Registration, NTR5469, registered on 03-09-2015. Protocol FORCE trial V18, 19-09-2019. Sponsor Radboud University Medical Center, Nijmegen.

Validation of a Novel Semiautomated Segmentation Method for MRI Detection of Cartilage-Related Bone Marrow Lesions.

OBJECTIVE: To determine the relationship of bone marrow lesions (BMLs) with phenomena such as clinical symptoms, histological subchondral bone damage, and development of osteoarthritis, a reliable and reproducible method to localize and quantify BMLs accurately is indispensable. Therefore, the goal of the current study was to develop and validate a novel semiautomated segmentation method based on the KNN classification technique on T2-weighted (T2w) SPIR and proton density-weighted (PDw) magnetic resonance images (MRIs), as this would provide an accurate, reliable, and reproducible tool. MATERIALS AND METHODS: Twenty PDw and T2w SPIR MRIs were selected and manually segmented as a learning set for the software system. The manual segmentations were considered the gold standard. Automated segmentation based on the KNN classification technique was carried out on the same MRIs. To determine the accuracy and validity of the system, the automated segmentations were compared to the gold standard using the Dice Similarity Index (DSI). RESULTS: The KNN classification system resulted both visually and statistically in an accurate segmentation of BMLs on T2w SPIR MRIs with an excellent mean optimal DSI of 0.702 (±0.202; range, 0.409-0.908). Elimination of specific areas smaller than 10 voxels improved the accuracy. The accuracy was independent of BML size. The segmentation of BMLs on PDw MRIs was less reliable with a mean optimal DSI of 0.536 (±0.156). CONCLUSION: Although the applicability of this method is limited on PDw MRIs, the KNN classification system provides an accurate, reliable, and reproducible tool for semiautomated segmentation of BMLs in T2w SPIR MRIs of the knee.

Magnetic resonance cholangiopancreaticography as a diagnostic tool for common bile duct stones: a comparison with ERCP and clinical follow-up.

BACKGROUND/AIMS: The diagnostic potential of magnetic resonance cholangiopancreaticography (MRCP) has improved as a result of evolving technique. MRCP has the advantage of negligible morbidity and mortality in contrast to endoscopic retrograde cholangiopancreatography (ERCP). This study was performed to evaluate MRCP as a replacement for diagnostic ERCP for the suspicion of common bile duct (CBD) stones. METHODS: From 1998 to 2001, MRCP was performed in 202 patients with a suspicion of CBD stones based on medical history (MH), cholestatic liver function tests (CL), both MH and CL or other reasons. ERCP was performed in all patients where MRCP indicated the presence of CBD stones and in those patients with a persistent strong clinical suspicion for CBD stones despite a negative MRCP. RESULTS: In 25 patients, MRCP suggested CBD stones which were proven with ERCP in 24 patients. Despite a negative MRCP, 27 patients had a subsequent ERCP. None of these patients appeared to have CBD stones. In this group, MRCP resulted in 100% sensitivity and 96% specificity in detecting CBD stones. Follow-up of all patients revealed 5 more patients with persistent clinical suspicion or cholestatic liver function values. Assuming CBD stones in these patients, MRCP had a sensitivity of 83 % and a specificity of 99% for this diagnosis. CONCLUSION: In the case of CBD stone suspicion, MRCP should be the diagnostic procedure of choice.

Crystal structure of Escherichia coli lytic transglycosylase Slt35 reveals a lysozyme-like catalytic domain with an EF-hand.

BACKGROUND: Lytic transglycosylases are bacterial muramidases that catalyse the cleavage of the beta- 1,4-glycosidic bond between N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc) in peptidoglycan with concomitant formation of a 1,6-anhydrobond in the MurNAc residue. These muramidases play an important role in the metabolism of the bacterial cell wall and might therefore be potential targets for the rational design of antibacterial drugs. One of the lytic transglycosylases is Slt35, a naturally occurring soluble fragment of the outer membrane bound lytic transglycosylase B (MltB) from Escherichia coli. RESULTS: The crystal structure of Slt35 has been determined at 1.7 A resolution. The structure reveals an ellipsoid molecule with three domains called the alpha, beta and core domains. The core domain is sandwiched between the alpha and beta domains. Its fold resembles that of lysozyme, but it contains a single metal ion binding site in a helix-loop-helix module that is surprisingly similar to the eukaryotic EF-hand calcium-binding fold. Interestingly, the Slt35 EF-hand loop consists of 15 residues instead of the usual 12 residues. The only other prokaryotic proteins with an EF-hand motif identified so far are the D-galactose-binding proteins. Residues from the alpha and core domains form a deep groove where the substrate fragment GlcNAc can be bound. CONCLUSIONS: The three-domain structure of Slt35 is completely different from the Slt70 structure, the only other lytic transglycosylase of known structure. Nevertheless, the core domain of Slt35 closely resembles the fold of the catalytic domain of Slt70, despite the absence of any obvious sequence similarity. Residue Glu162 of Slt35 is in an equivalent position to Glu478, the catalytic acid/base of Slt70. GlcNAc binds close to Glu162 in the deep groove. Moreover, mutation of Glu162 into a glutamine residue yielded a completely inactive enzyme. These observations indicate the location of the active site and strongly support a catalytic role for Glu162.

Identification of new members of the lytic transglycosylase family in Haemophilus influenzae and Escherichia coli.

Although bacterial peptidoglycan metabolism and numerous of the enzymes involved therein have been studied extensively over the years, information on the precise number of these enzymes is still lacking as is knowledge on the specific function of most of them. This observation holds true even for the well-studied bacterium Escherichia coli. Through determination of the complete sequences of bacterial genomes, that of Haemophilus influenzae being the first example, the opportunity arises to obtain a comprehensive overview of the members of the different families of peptidoglycan metabolizing enzymes by identification of their genes. Following this rationale, H. influenzae and E. coli genomic sequence was searched for new members of the family of lytic transglycosylases, using three-dimensional structure-derived sequence information. A new putative lytic transglycosylase gene could be identified in both bacterial species. The gene from E. coli was cloned and peptidoglycan hydrolase activity was demonstrated for the gene product.

Cloning and controlled overexpression of the gene encoding the 35 kDa soluble lytic transglycosylase from Escherichia coli.

The lytic transglycosylases of Escherichia coli are involved in peptidoglycan metabolism and resemble the lysozymes not only in activity, but in the case of the 70 kDa soluble lytic transglycosylase (Slt70), also structurally. Here we report the cloning of the gene that encodes the 35 kDa soluble lytic transglycosylase (Slt35) of E. coli. Based on the sequence of the full-length gene, Slt35 is very likely to be a proteolytically truncated form of a slightly larger protein. The homology between Slt35 and Slt70, albeit poor, indicates that the active site architecture of both proteins may be alike. Using the T-7 promoter system, Slt35 was overproduced in large quantities and purified to homogeneity for crystallographic purposes.

G(AnH)MTetra, a naturally occurring 1,6-anhydro muramyl dipeptide, induces granulocyte colony-stimulating factor expression in human monocytes: a molecular analysis.

N-Acetylglucosaminyl-1,6-anhydro-N-acetylmuramyl-L-alanyl-D-isoglutam yl-m- diaminopimelyl-D-alanine [G (Anh)MTetra], a naturally occurring breakdown product of peptidoglycan from bacterial cell walls, was studied for its ability to induce granulocyte colony-stimulating factor (G-CSF) mRNA and protein expression in human adherent monocytes. Resting monocytes did not express G-CSF mRNA or secrete G-CSF protein. In contrast, monocytes exposed to G(Anh)MTetra showed a dose-dependent increase in G-CSF mRNA accumulation, which correlates with the secretion of G-CSF protein. Maximal levels of G-CSF mRNA were reached within 2 h of activation. Expression of G-CSF was mediated by an increase in the stability of G-CSF transcripts rather than by an increase in the transcription rate of the G-CSF gene. Experiments with the protein synthesis inhibitor cycloheximide revealed that G(Anh)MTetra-induced G-CSF mRNA expression was independent of new protein synthesis. Furthermore, it was shown that the effect of G(Anh)MTetra was regulated by a protein kinase C-dependent pathway, whereas protein kinase A and tyrosine kinases were not involved. Finally, it was shown that G(Anh)MTetra also induced G-CSF mRNA expression in human endothelial cells. The data indicate that, besides lipopolysaccharide, other naturally occurring bacterial cell wall components are able to induce G-CSF expression in different hematopoietic cells.

Doughnut-shaped structure of a bacterial muramidase revealed by X-ray crystallography.

The integrity of the bacterial cell wall depends on the balanced action of several peptidoglycan (murein) synthesizing and degrading enzymes. Penicillin inhibits the enzymes responsible for peptide crosslinks in the peptidoglycan polymer. Enzymes that act solely on the glycosidic bonds are insensitive to this antibiotic, thus offering a target for the design of antibiotics distinct from the beta-lactams. Here we report the X-ray structure of the periplasmic soluble lytic transglycosylase (SLT; M(r) 70,000) from Escherichia coli. This unique bacterial exomuramidase cleaves the beta-1,4-glycosidic bonds of peptidoglycan to produce small 1,6-anhydromuropeptides. The structure of SLT reveals a 'superhelical' ring of alpha-helices with a separate domain on top which resembles the fold of lysozyme. Site-directed mutagenesis and a crystallographic inhibitor-binding study confirmed that the lysozyme-like domain contains the active site of SLT.

G(Anh)MTetra, a natural bacterial cell wall breakdown product, induces interleukin-1 beta and interleukin-6 expression in human monocytes. A study of the molecular mechanisms involved in inflammatory cytokine expression.

It is believed that induction of cytokine expression by bacterial cell wall components plays a role in the development and course of sepsis. However, most attention has been focused on lipopolysaccharide (LPS). We studied the ability of N-acetylglucosaminyl-1,6-anhydro-N-acetylmuramyl-L-alanyl-D- isoglutamyl-m-diaminopimelyl-D-alanine (G(Anh)MTetra), a naturally occurring breakdown product of peptidoglycan that is produced by soluble lytic transglycosylase of Escherichia coli, to induce cytokine expression in human monocytes. G(Anh)MTetra was found to strongly induce interleukin (IL)-1 beta and IL-6 mRNA expression after 2 h and IL-1 beta and IL-6 protein secretion after 48 h of activation. The increase in mRNA accumulation was at least partly due to an increase in the transcription rates of the respective genes and was accompanied by a strong induction of nuclear factor-kappa B and activator protein-1 transcription factor expression. Experiments using inhibitors of protein kinase C, protein kinase A, and tyrosine kinase-dependent pathways revealed that G(Anh)MTetra-induced IL-1 beta and IL-6 mRNA expression involves activation of an H7-inhibitable pathway. By using the protein synthesis inhibitor cycloheximide, it was shown that G(Anh)MTetra-induced IL-6 mRNA expression depends on the synthesis of new protein, whereas G(Anh)MTetra-induced IL-1 beta mRNA accumulation does not. When responses to G(Anh)MTetra were compared with those to LPS and muramyldipeptide (MDP), it was found that the optimal response to G(Anh)MTetra induction was similar to that of LPS but significantly higher than the response to MDP. Furthermore, maximal G(Anh)MTetra-induced IL-1 beta and IL-6 mRNA expression could be enhanced by co-stimulation with LPS or MDP, suggesting that different receptors and/or transduction pathways were involved. These results indicate that G(Anh)MTetra induces IL-1 beta and IL-6 expression in human monocytes suggesting a possible role for G(Anh)MTetra in the release of cytokines during sepsis.