What surgeons tell patients and what patients want to know before major cancer surgery: a qualitative study.

BACKGROUND: The information surgeons impart to patients and information patients want about surgery for cancer is important but rarely examined. This study explored information provided by surgeons and patient preferences for information in consultations in which surgery for oesophageal cancer surgery was discussed. METHODS: Pre-operation consultations in which oesophagectomy was discussed were studied in three United Kingdom hospitals and patients were subsequently interviewed. Consultations and interviews were audio-recorded, transcribed in full and anonymized. Interviews elicited views about the information provided by surgeons and patients' preferences for information. Thematic analysis of consultation-interview pairs was used to investigate similarities and differences in the information provided by surgeons and desired by patients. RESULTS: Fifty two audio-recordings from 31 patients and 7 surgeons were obtained (25 consultations and 27 patient interviews). Six consultations were not recorded because of equipment failure and four patients declined an interview. Surgeons all provided consistent, extensive information on technical operative details and in-hospital surgical risks. Consultations rarely included discussion of the longer-term outcomes of surgery. Whilst patients accepted that information about surgery and risks was necessary, they really wanted details about long-term issues including recovery, impact on quality of life and survival. CONCLUSIONS: This study demonstrated a need for surgeons to provide information of importance to patients concerning the longer term outcomes of surgery. It is proposed that "core information sets" are developed, based on surgeons' and patients' views, to use as a minimum in consultations to initiate discussion and meet information needs prior to cancer surgery.

Activation of intestinal spinal afferent endings by changes in intra-mesenteric arterial pressure.

KEY POINTS: A major class of mechano-nociceptors to the intestine have mechanotransduction sites on extramural and intramural arteries and arterioles ('vascular afferents'). These sensory neurons can be activated by compression or axial stretch of vessels. Using isolated preparations we showed that increasing intra-arterial pressure, within the physiological range, activated mechano-nociceptors on vessels in intact mesenteric arcades, but not in isolated arteries. This suggests that distortion of the branching vascular tree is the mechanical adequate stimulus for these sensory neurons, rather than simple distension. The same rises in pressure also activated intestinal peristalsis in a partially capsaicin-sensitive manner indicating that pressure-sensitive vascular afferents influence enteric circuits. The results identify the mechanical adequate stimulus for a major class of mechano-nociceptors with endings on blood vessels supplying the gut wall; these afferents have similar endings to ones supplying other viscera, striated muscle and dural vessels. ABSTRACT: Spinal sensory neurons innervate many large blood vessels throughout the body. Their activation causes the hallmarks of neurogenic inflammation: vasodilatation through the release of the neuropeptide calcitonin gene-related peptide and plasma extravasation via tachykinins. The same vasodilator afferent neurons show mechanical sensitivity, responding to crushing, compression or axial stretch of blood vessels - responses which activate pain pathways and which can be modified by cell damage and inflammation. In the present study, we tested whether spinal afferent axons ending on branching mesenteric arteries ('vascular afferents') are sensitive to increased intravascular pressure. From a holding pressure of 5 mmHg, distension to 20, 40, 60 or 80 mmHg caused graded, slowly adapting increases in firing of vascular afferents. Many of the same afferent units showed responses to axial stretch, which summed with responses evoked by raised pressure. Many vascular afferents were also sensitive to raised temperature, capsaicin and/or local compression with von Frey hairs. However, responses to raised pressure in single, isolated vessels were negligible, suggesting that the adequate stimulus is distortion of the arterial arcade rather than distension per se. Increasing arterial pressure often triggered peristaltic contractions in the neighbouring segment of intestine, an effect that was mimicked by acute exposure to capsaicin (1 µm) and which was reduced after desensitisation to capsaicin. These results indicate that sensory fibres with perivascular endings are sensitive to pressure-induced distortion of branched arteries, in addition to compression and axial stretch, and that they contribute functional inputs to enteric motor circuits.

Core information set for oesophageal cancer surgery.

BACKGROUND: Surgeons provide patients with information before surgery, although standards of information are lacking and practice varies. The development and use of a 'core information set' as baseline information before surgery may improve understanding. A core set is a minimum set of information to use in all consultations before a specific procedure. This study developed a core information set for oesophageal cancer surgery. METHODS: Information was identified from the literature, observations of clinical consultations and patient interviews. This was integrated to create a questionnaire survey. Stakeholders (patients and professionals) were surveyed twice to assess views on importance of information from 'not essential' to 'absolutely essential' using Delphi methods. Items not meeting predefined criteria were discarded after each survey and the final retained items were voted on, in separate patient and professional stakeholder meetings, to agree the core set. RESULTS: Some 67 information items were identified initially from multiple sources. Survey response rates were 76·5 per cent (185 of 242) and 54·8 per cent (126 of 230) for patients and professionals respectively (first round), and over 83 per cent in both groups thereafter. Health professionals rated short-term clinical outcomes most highly (technical complications), whereas patients prioritized information related to long-term benefits. The consensus meetings agreed the final set, which consisted of: in-hospital milestones to recovery, rates of open-and-close surgery, in-hospital mortality, major complications (reoperation), milestones in recovery after discharge, longer-term eating and drinking and overall quality of life, and chances of survival. CONCLUSION: This study has established a core information set for surgery for oesophageal cancer.

Synthesis and summary of patient-reported outcome measures to inform the development of a core outcome set in colorectal cancer surgery.

AIM: Patient-reported outcome (PRO) measures (PROMs) are standard measures in the assessment of colorectal cancer (CRC) treatment, but the range and complexity of available PROMs may be hindering the synthesis of evidence. This systematic review aimed to: (i) summarize PROMs in studies of CRC surgery and (ii) categorize PRO content to inform the future development of an agreed minimum 'core' outcome set to be measured in all trials. METHOD: All PROMs were identified from a systematic review of prospective CRC surgical studies. The type and frequency of PROMs in each study were summarized, and the number of items documented. All items were extracted and independently categorized by content by two researchers into 'health domains', and discrepancies were discussed with a patient and expert. Domain popularity and the distribution of items were summarized. RESULTS: Fifty-eight different PROMs were identified from the 104 included studies. There were 23 generic, four cancer-specific, 11 disease-specific and 16 symptom-specific questionnaires, and three ad hoc measures. The most frequently used PROM was the EORTC QLQ-C30 (50 studies), and most PROMs (n = 40, 69%) were used in only one study. Detailed examination of the 50 available measures identified 917 items, which were categorized into 51 domains. The domains comprising the most items were 'anxiety' (n = 85, 9.2%), 'fatigue' (n = 67, 7.3%) and 'physical function' (n = 63, 6.9%). No domains were included in all PROMs. CONCLUSION: There is major heterogeneity of PRO measurement and a wide variation in content assessed in the PROMs available for CRC. A core outcome set will improve PRO outcome measurement and reporting in CRC trials.

Feasibility RCT of definitive chemoradiotherapy or chemotherapy and surgery for oesophageal squamous cell cancer.

BACKGROUND: The optimal treatment for localised oesophageal squamous cell carcinoma (SCC) is uncertain. We assessed the feasibility of an RCT comparing neoadjuvant treatment and surgery with definitive chemoradiotherapy. METHODS: A feasibility RCT in three centres examined incident patients and reasons for ineligibility using multi-disciplinary team meeting records. Eligible patients were offered participation in the RCT with integrated qualitative research involving audio-recorded recruitment appointments and interviews with patients to inform recruitment training for staff. RESULTS: Of 375 patients with oesophageal SCC, 42 (11.2%) were eligible. Reasons for eligibility varied between centres, with significantly differing proportions of patients excluded because of total tumour length (P=0.002). Analyses of audio-recordings and patient interviews showed that recruiters had challenges articulating the trial design in simple terms, balancing treatment arms and explaining the need for randomisation. Before analyses of the qualitative data and recruiter training no patients were randomised. Following training in one centre 5 of 16 eligible patients were randomised. CONCLUSIONS: An RCT of surgical vs non-surgical treatment for SCC of the oesophagus is not feasible in the UK alone because of the low number of incident eligible patients. A trial comparing diverse treatment approaches may be possible with investment to support the recruitment process.

Patient-reported outcomes in long-term survivors of metastatic colorectal cancer needing liver resection.

BACKGROUND: Five-year survival after hepatic resection for colorectal cancer (CRC) liver metastases is good, but data on patient-reported outcomes are lacking. This study describes the long-term impact of liver surgery for CRC metastases on patient-reported outcomes. METHODS: The study used the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ) C30 and the disease-specific module, EORTC QLQ-LMC21. For functional scales, mean scores out of 100 with 95 per cent c.i. were calculated; differences of 10 points or more were considered clinically significant. Responses to symptom scales and items were categorized as 'minimal' or 'severe'. Proportions and 95 per cent c.i. for symptoms were calculated. RESULTS: A total of 241 patients were recruited; nine (3·7 per cent) had unresectable disease and were excluded. Some 68 (42 men) of 80 long-term survivors participated; their mean age was 69·5 years and median follow-up was 8·0 (range 6·9-9·2) years. Values for baseline and 1-year patient-reported outcome data were similar. Scores for functional scales were excellent (emotional function: 92, 95 per cent c.i. 87 to 96; social function: 94, 89 to 99; role function: 94, 90 to 98), reflecting clinically significant improvements from baseline values of 17 (10 to 24), 12 (3 to 21) and 12 (3 to 20) respectively. Severe symptoms were uncommon (affected less than 5 per cent of patients) for most patient-reported outcome scales or items, but persistent severe symptoms were noted for sexual function (2 per cent increase from baseline), peripheral neuropathy (2 per cent increase), constipation (10 per cent increase) and diarrhoea (5 per cent increase). CONCLUSION: Long-term survivors of metastatic colorectal cancer who have undergone liver surgery have excellent global quality of life, high levels of function and few symptoms.

Antibody elution with 2-me/SDS solution: Uses for multi-layer immunohistochemical analysis of wholemount preparations of human colonic myenteric plexus.

Indirect immunofluorescence is usually restricted to 3-5 markers per preparation, limiting analysis of coexistence. A solution containing 2-mercaptoethanol and sodium dodecyl sulfate (2-ME/SDS) can elute indirect immunofluorescence labelling (i.e. primary antisera followed by fluorophore-conjugated secondary antisera) and has been used for sequential staining of sections. The aim of this study was to test whether 2-ME/SDS is effective for eluting indirect immunofluorescent staining (with primary antisera visualised by fluorophore-coupled secondary antisera) in wholemount preparations. We also analysed how 2-ME/SDS may work and used this understanding to devise additional uses for immunofluorescence in the nervous system. 2-ME/SDS appears to denature unfixed proteins (including antisera used as reagents) but has much less effect on antigenicity of formaldehyde-fixed epitopes. Moieties linked by strong biotin-streptavidin bonds are highly resistant to elution by 2-ME/SDS. Two primary antisera raised in the same species can be applied without spurious cross-reactivity, if a specific order of labelling is followed. The first primary antiserum is followed by a biotinylated secondary, then a tertiary of fluorophore-conjugated streptavidin. The preparation is then exposed to 2-ME/SDS, which has minimal impact on labelling by the first primary/secondary/tertiary combination. However, when this is followed by a second primary antiserum (raised in the same species), followed by a fluorophore-conjugated secondary antiserum, the intervening 2-ME/SDS exposure prevents cross-reactivity between primary and secondary antisera of the two layers. A third property of 2-ME/SDS is that it reduces lipofuscin autofluorescence, although it also raises background fluorescence and strongly enhances autofluorescence of erythrocytes. In summary, 2-ME/SDS is easy to use, cost-effective and does not require modified primary antisera. It can be used as the basis of a multi-layer immunohistochemistry protocol and allows 2 primary antisera raised in the same species to be used together.

Peristalsis and propulsion of colonic content can occur after blockade of major neuroneuronal and neuromuscular transmitters in isolated guinea pig colon.

We recently identified hexamethonium-resistant peristalsis in the guinea pig colon. We showed that, following acute blockade of nicotinic receptors, peristalsis recovers, leading to normal propagation velocities of fecal pellets along the colon. This raises the fundamental question: what mechanisms underlie hexamethonium-resistant peristalsis? We investigated whether blockade of the major receptors that underlie excitatory neuromuscular transmission is required for hexamethonium-resistant peristalsis. Video imaging of colonic wall movements was used to make spatiotemporal maps and determine the velocity of peristalsis. Propagation of artificial fecal pellets in the guinea pig distal colon was studied in hexamethonium, atropine, ω-conotoxin (GVIA), ibodutant (MEN-15596), and TTX. Hexamethonium and ibodutant alone did not retard peristalsis. In contrast, ω-conotoxin abolished peristalsis in some preparations and reduced the velocity of propagation in all remaining specimens. Peristalsis could still occur in some animals in the presence of hexamethonium + atropine + ibodutant + ω-conotoxin. Peristalsis never occurred in the presence of TTX. The major finding of the current study is the unexpected observation that peristalsis can occur after blockade of the major excitatory neuroneuronal and neuromuscular transmitters. Also, the colon retained an intrinsic polarity in the presence of these antagonists and was only able to expel pellets in an aboral direction. The nature of the mechanism(s)/neurotransmitter(s) that generate(s) peristalsis and facilitate(s) natural fecal pellet propulsion, after blockade of major excitatory neurotransmitters, at the neuroneuronal and neuromuscular junction remains to be identified.

Neurogenic and myogenic motor activity in the colon of the guinea pig, mouse, rabbit, and rat.

Gastrointestinal motility involves interactions between myogenic and neurogenic processes intrinsic to the gut wall. We have compared the presence of propagating myogenic contractions of the isolated colon in four experimental animals (guinea pig, mouse, rabbit, and rat), following blockade of enteric neural activity. Isolated colonic preparations were distended with fluid, with the anal end either closed or open. Spatiotemporal maps of changes in diameter were constructed from video recordings. Distension-induced peristaltic contractions were abolished by tetrodotoxin (TTX; 0.6 µM) in all animal species. Subsequent addition of carbachol (0.1-1 µM) did not evoke myogenic motor patterns in the mouse or guinea pig, although some activity was observed in rabbit and rat colon. These myogenic contractions propagated both orally and anally and differed from neurogenic propagating contractions in their frequency, extent of propagation, and polarity. Niflumic acid (300 µM), used to block myogenic activity, also blocked neural peristalsis and thus cannot be used to discriminate between these mechanisms. In all species, except the mouse colon, small myogenic "ripple" contractions were revealed in TTX, but in both rat and rabbit an additional, higher-frequency ripple-type contraction was superimposed. Following blockade of enteric nerve function, a muscarinic agonist can evoke propulsive myogenic peristaltic contractions in isolated rabbit and rat colon, but not in guinea pig or mouse colon. Marked differences between species exist in the ability of myogenic mechanisms to propel luminal content, but in all species there is normally a complex interplay between neurogenic and myogenic processes.

A systematic review of outcome reporting in colorectal cancer surgery.

AIM: Evaluation of surgery for colorectal cancer (CRC) is necessary to inform clinical decision-making and healthcare policy. The standards of outcome reporting after CRC surgery have not previously been considered. METHOD: Systematic literature searches identified randomized and nonrandomized prospective studies reporting clinical outcomes of CRC surgery. Outcomes were listed verbatim, categorized into broad groups (outcome domains) and examined for a definition (an appropriate textual explanation or a supporting citation). Outcome reporting was considered inconsistent if results of the outcome specified in the methods were not reported. Outcome reporting was compared between randomized and nonrandomized studies. RESULTS: Of 5644 abstracts, 194 articles (34 randomized and 160 nonrandomized studies) were included reporting 766 different clinical outcomes, categorized into seven domains. A mean of 14 ± 8 individual outcomes were reported per study. 'Anastomotic leak', 'overall survival' and 'wound infection' were the three most frequently reported outcomes in 72, 60 and 44 (37.1%, 30.9% and 22.7%) studies, respectively, and no single outcome was reported in every publication. Outcome definitions were significantly more often provided in randomized studies than in nonrandomized studies (19.0% vs 14.9%, P = 0.015). One-hundred and twenty-seven (65.5%) papers reported results of all outcomes specified in the methods (randomized studies, n = 21, 61.5%; nonrandomized studies, n = 106, 66.2%; P = 0.617). CONCLUSION: Outcome reporting in CRC surgery lacks consistency and method. Improved standards of outcome measurement are recommended to permit data synthesis and transparent cross-study comparisons.

Neurogenic and myogenic motor patterns of rabbit proximal, mid, and distal colon.

The rabbit colon consists of four distinct regions. The motility of each region is controlled by myogenic and neurogenic mechanisms. Associating these mechanisms with specific motor patterns throughout all regions of the colon has not previously been achieved. Three sections of the colon (the proximal, mid, and distal colon) were removed from euthanized rabbits. The proximal colon consists of a triply teniated region and a single tenia region. Spatio-temporal maps were constructed from video recordings of colonic wall diameter, with associated intraluminal pressure recorded from the aboral end. Hexamethonium (100 µM) and tetrodotoxin (TTX; 0.6 µM) were used to inhibit neural activity. Four distinct patterns of motility were detected: 1 myogenic and 3 neurogenic. The myogenic activity consisted of circular muscle (CM) contractions (ripples) that occurred throughout the colon and propagated in both antegrade (anal) and retrograde (oral) directions. The neural activity of the proximal colon consisted of slowly (0.1 mm/s) propagating colonic migrating motor complexes, which were abolished by hexamethonium. These complexes were observed in the region of the proximal colon with a single band of tenia. In the distal colon, tetrodotoxin-sensitive, thus neurally mediated, but hexamethonium-resistant, peristaltic (anal) and antiperistaltic (oral) contractions were identified. The distinct patterns of neurogenic and myogenic motor activity recorded from isolated rabbit colon are specific to each anatomically distinct region. The regional specificity motor pattern is likely to facilitate orderly transit of colonic content from semi-liquid to solid composition of feces.

Pathology associated with a human case of rabies in the United Kingdom caused by European bat lyssavirus type-2.

Human infection with the rabies-related virus European bat lyssavirus type-2 (EBLV-2) has only been reported on two occasions. Here we report the pathology observed within spinal cord and visceral tissues associated with EBLV-2 infection for the first time. Neuronal labelling with an anti-rabies nucleocapsid monoclonal antibody was observed and appeared indistinguishable from the labelling reported from human infection with rabies virus.

Temporal relationships between wall motion, intraluminal pressure, and flow in the isolated rabbit small intestine.

Intraluminal manometry is a tool commonly used to record motility in the human digestive tract. The recorded signal results from a combination of factors, including the hydrodynamic pressure transmitted through the intestinal contents due to contraction of the gut wall and the force of the gut wall acting on the sensors in regions of a luminal occlusion. However, the actual relationships between small bowel wall contraction, the measured intraluminal pressure, and the resultant flow have not been directly addressed. Video recording and high-resolution fiber-optic manometry were used to create spatiotemporal video maps of diameter and intraluminal pressure from isolated segments of rabbit small intestine. In the unstimulated gut, longitudinal muscle contractions were the only detectable motor pattern; circular muscle contractions were elicited by distension or erythromycin (1 µM). Longitudinal muscle contractions were not lumen-occlusive, although they caused measurable low-amplitude changes in pressure. Localized nonpropagating circular muscle contractions caused small localized, nonpropagating peaks of intraluminal pressure. Propagating contractions of circular muscle evoked larger, propagating pressure changes that were associated with outflow. Propagating circular muscle contractions often caused dilation of aboral receiving segments, corresponding to "common cavities"; these were propulsive, despite their low intraluminal pressure. The highest-amplitude pressure events were caused by lumen-occlusive circular muscle contractions that squeezed directly against the catheter. These data allow us to define the complex relationships between wall motion, intraluminal pressure, and flow. A strong correlation between circular and longitudinal muscle contraction and intraluminal pressure was demonstrated. Common-cavity pressure events, caused by propulsion of content by circular muscle contractions into a receptive segment, were often of low amplitude but were highly propulsive. Studies of wall motion in isolated preparations, combined with manometry, can assist in interpretation of pressure recordings in vivo.

Highly pathogenic avian influenza virus H5N6 (clade 2.3.4.4b) has a preferable host tropism for waterfowl reflected in its inefficient transmission to terrestrial poultry.

Highly-pathogenic avian influenza virus (HPAIV) H5N6 (clade 2.3.4.4b) incurred into Europe in late 2017 and was predominantly detected in wild birds, with very few terrestrial poultry cases. Pekin ducks directly-infected with a UK virus (H5N6-2017) were donors of infection to investigate contact transmission to three recipient species: Ducks, chickens and turkeys. H5N6-2017 transmission to ducks was 100% efficient, but transmission to in-contact galliforme species was infrequent and unpredictable, thereby reflecting the European 2017-2018 H5N6 epidemiology. Although only two of 28 (7%) infected ducks died, the six turkeys and one chicken which became infected all died and displayed systemic H5N6-2017 dissemination, while pathogenesis in ducks was generally milder. Analysis of H5N6-2017 progeny in the contacts revealed no emergent polymorphisms in an infected duck, but the galliforme species included changes in the polymerase (PB2 A199T, PA D347A), matrix (M1 T218A) and neuraminidase genes (T88I). H5N6-2017 environmental contamination was associated with duck shedding.

Assessing the risks of SARS-CoV-2 in wildlife.

The novel coronavirus SARS-CoV-2 likely emerged from a wildlife source with transmission to humans followed by rapid geographic spread throughout the globe and severe impacts on both human health and the global economy. Since the onset of the pandemic, there have been many instances of human-to-animal transmission involving companion, farmed and zoo animals, and limited evidence for spread into free-living wildlife. The establishment of reservoirs of infection in wild animals would create significant challenges to infection control in humans and could pose a threat to the welfare and conservation status of wildlife. We discuss the potential for exposure, onward transmission and persistence of SARS-CoV-2 in an initial selection of wild mammals (bats, canids, felids, mustelids, great apes, rodents and cervids). Dynamic risk assessment and targeted surveillance are important tools for the early detection of infection in wildlife, and here we describe a framework for collating and synthesising emerging information to inform targeted surveillance for SARS-CoV-2 in wildlife. Surveillance efforts should be integrated with information from public and veterinary health initiatives to provide insights into the potential role of wild mammals in the epidemiology of SARS-CoV-2.

The structure and composition of deciduous enamel affected by local hypoplastic autosomal dominant amelogenesis imperfecta resulting from an ENAM mutation.

In a group of families in northern Sweden, a mutation in the ENAM gene (predicted to produce a highly truncated protein) results in the local hypoplastic form of autosomal dominant amelogenesis imperfecta. In this study, sections of deciduous teeth from members of 3 of these families were examined by scanning electron microscopy (SEM) and the enamel mineral was analysed by energy dispersive X-ray spectroscopy (EDX). The sections were also probed with antibodies raised to a conserved sequence of the enamelin protein. Selected intact teeth were first analysed by digital imaging and ascribed with an 'Enamel Defects Index' (EDI) score. SEM of tooth sections revealed disrupted prism morphology and the prisms had a glass-like appearance in some areas. These areas of dysplasia were sometimes irregular but formed regular arrays in others. Comparison of EDI scores with SEM indicated that in one tooth the surface had no measurable defects but significant defects were present in the underlying enamel microstructure. SEM immunohistochemistry with the antibody raised to a fragment of the enamelin protein produced positive, but light, labelling throughout normal enamel. In dysplastic areas, however, the labelling intensity appeared to be reduced. The results indicate that the presence of functional enamelin in the correct amounts is necessary for correct prism morphogenesis. In addition, a combination of EDI and structural analysis indicate that defects in enamel microstructure are not necessarily visible as defects on the surface of the tooth, suggesting the possibility, at least, that some instances of under-diagnosis may occur.

Post-inflammatory colonic afferent sensitisation: different subtypes, different pathways and different time courses.

OBJECTIVE: Intestinal infection evokes hypersensitivity in a subgroup of patients with irritable bowel syndrome (IBS) long after healing of the initial injury. Trinitrobenzene sulfonic acid (TNBS)-induced colitis in rodents likewise results in delayed maintained hypersensitivity, regarded as a model of some aspects of IBS. The colon and rectum have a complex sensory innervation, comprising five classes of mechanosensitive afferents in the splanchnic and pelvic nerves. Their plasticity may hold the key to underlying mechanisms in IBS. Our aim was therefore to determine the contribution of each afferent class in each pathway towards post-inflammatory visceral hypersensitivity. DESIGN: TNBS was administered rectally and mice were studied after 7 (acute) or 28 (recovery) days. In vitro preparations of mouse colorectum with attached pelvic or splanchnic nerves were used to examine the mechanosensitivity of individual colonic afferents. RESULTS: Mild inflammation of the colon was evident acutely which was absent at the recovery stage. TNBS treatment did not alter proportions of the five afferent classes between treatment groups. In pelvic afferents little or no difference in response to mechanical stimuli was apparent in any class between control and acute mice. However, major increases in mechanosensitivity were recorded from serosal afferents in mice after recovery, while responses from other subtypes were unchanged. Both serosal and mesenteric splanchnic afferents were hypersensitive at both acute and recovery stages. CONCLUSIONS: Colonic afferents with high mechanosensory thresholds contribute to inflammatory hypersensitivity, but not those with low thresholds. Pelvic afferents become involved mainly following recovery from inflammation, whereas splanchnic afferents are implicated during both inflammation and recovery.

A Novel Mode of Sympathetic Reflex Activation Mediated by the Enteric Nervous System.

Enteric viscerofugal neurons provide a pathway by which the enteric nervous system (ENS), otherwise confined to the gut wall, can activate sympathetic neurons in prevertebral ganglia. Firing transmitted through these pathways is currently considered fundamentally mechanosensory. The mouse colon generates a cyclical pattern of neurogenic contractile activity, called the colonic motor complex (CMC). Motor complexes involve a highly coordinated firing pattern in myenteric neurons with a frequency of ∼2 Hz. However, it remains unknown how viscerofugal neurons are activated and communicate with the sympathetic nervous system during this naturally-occurring motor pattern. Here, viscerofugal neurons were recorded extracellularly from rectal nerve trunks in isolated tube and flat-sheet preparations of mouse colon held at fixed circumferential length. In freshly dissected preparations, motor complexes were associated with bursts of viscerofugal firing at 2 Hz that aligned with 2-Hz smooth muscle voltage oscillations. This behavior persisted during muscle paralysis with nicardipine. Identical recordings were made after a 4- to 5-d organotypic culture during which extrinsic nerves degenerated, confirming that recordings were from viscerofugal neurons. Single unit analysis revealed the burst firing pattern emerging from assemblies of viscerofugal neurons differed from individual neurons, which typically made partial contributions, highlighting the importance and extent of ENS-mediated synchronization. Finally, sympathetic neuron firing was recorded from the central nerve trunks emerging from the inferior mesenteric ganglion. Increased sympathetic neuron firing accompanied all motor complexes with a 2-Hz burst pattern similar to viscerofugal neurons. These data provide evidence for a novel mechanism of sympathetic reflex activation derived from synchronized firing output generated by the ENS.

Enamel matrix proteins; old molecules for new applications.

Emdogain (enamel matrix derivative, EMD) is well recognized in periodontology, where it is used as a local adjunct to periodontal surgery to stimulate regeneration of periodontal tissues lost to periodontal disease. The biological effect of EMD is through stimulation of local growth factor secretion and cytokine expression in the treated tissues, inducing a regenerative process that mimics odontogenesis. The major (>95%) component of EMD is Amelogenins (Amel). No other active components have so far been isolated from EMD, and several studies have shown that purified amelogenins can induce the same effect as the complete EMD. Amelogenins comprise a family of highly conserved extracellular matrix proteins derived from one gene. Amelogenin structure and function is evolutionary well conserved, suggesting a profound role in biomineralization and hard tissue formation. A special feature of amelogenins is that under physiological conditions the proteins self-assembles into nanospheres that constitute an extracellular matrix. In the body, this matrix is slowly digested by specific extracellular proteolytic enzymes (matrix metalloproteinase) in a controlled process, releasing bioactive peptides to the surrounding tissues for weeks after application. Based on clinical and experimental observations in periodontology indicating that amelogenins can have a significant positive influence on wound healing, bone formation and root resorption, several new applications for amelogenins have been suggested. New experiments now confirm that amelogenins have potential for being used also in the fields of endodontics, bone regeneration, implantology, traumatology, and wound care.

Characterisation of One Class of Group III Sensory Neurons Innervating Abdominal Muscles of the Mouse.

Group III/IV striated muscle afferents are small diameter sensory neurons that play important roles in reflexes and sensation. To date, the morphological features of physiologically characterised group III/IV muscular afferents have not been identified. Here, the electrophysiological and morphological characteristics of sensory neurons innervating striated muscles of the mouse abdominal wall were investigated, ex vivo. Extracellular recordings were made from subcostal nerve trunks innervating the muscles. A distinctive class of mechanosensitive afferents was identified by a combination of physiological features including sensitivity to local compression, saturating response to graded stretch and, in most cases, absence of spontaneous firing. Studies were restricted to these distinctive units. These units had conduction velocities averaging 14 ±â€¯4 m/s (range: 8-20 m/s, n = 7); within the range of group III fibres in mice. Von Frey hairs were used to map receptive fields, which covered an area of 0.36 ±â€¯0.18 mm2 (n = 7). In 7 preparations, biotinamide filling of recorded nerve trunks revealed a single axon in the marked receptive field, with distinctive axonal branching and terminations meandering through the connective tissue sandwiched between two closely associated muscle layers. These axons were not immunoreactive for CGRP (n = 7) and were not activated by application of capsaicin (1 µM, n = 14). All of these afferents were strongly activated by a "metabolite mix" containing lactate, adenosine triphosphate and reduced pH. Responses to mechanical stimuli and to metabolites were additive. We have characterised a distinctive class of mechano- and chemo-sensitive group III afferent endings associated with connective tissue close to muscle fibres.