A look at duodenal mucosal resurfacing: Rationale for targeting the duodenum in type 2 diabetes

Affecting 5%-10% of the world population, type 2 diabetes (T2DM) is firmly established as one of the major health burdens of modern society. People with T2DM require long-term therapies to reduce blood glucose, an approach that can mitigate the vascular complications. However, fewer than half of those living with T2DM reach their glycaemic targets despite the availability of multiple oral and injectable medications. Adherence and access to medications are major barriers contributing to suboptimal diabetes treatment. The gastrointestinal tract has recently emerged as a target for treating T2DM and altering the underlying disease course. Preclinical and clinical analyses have elucidated changes in the mucosal layer of the duodenum potentially caused by dietary excess and obesity, which seem to be prevalent among individuals with metabolic disease. Supporting these findings, gastric bypass, a surgical procedure which removes the duodenum from the intestinal nutrient flow, has remarkable effects that improve, and often cause remission of, diabetes. From this perspective, we explore the rationale for targeting the duodenum with duodenal mucosal resurfacing (DMR). We examine the underlying physiology of the duodenum and its emerging role in T2DM pathogenesis, the rationale for targeting the duodenum by DMR as a potential treatment for T2DM, and current data surrounding DMR. Importantly, DMR has been demonstrated to change mucosal abnormalities common in those with obesity and diabetes. Given the multifactorial aetiology of T2DM, understanding proximate contributors to disease pathogenesis opens the door to rethinking therapeutic approaches to T2DM, from symptom management toward disease modification.

IBCOx-12 The Endoscopic Sleeve Gastroplasty Produces Durable Physiologic Changes: Results from a Randomized US Clinical Trial

Background

Obesity is associated with faster gastric emptying and altered appetite. Endoscopic sleeve gastroplasty (ESG) has gained global adaptation, but our understanding of its physiologic mechanism of action and durability is limited. We sought to determine changes in gastric emptying, weight loss, and eating behaviors after ESG when compared to moderate-intensity lifestyle interventions (LS) in the short and long-term.

Methods

This is an a priori designed sub-study of a large ongoing multicenter US RCT (MERIT trial), where adults with BMI 30-40 kg/m2 were randomized to ESG versus moderate-intensity LS alone. We measured gastric emptying (T1/2) using a 4- hour gastric emptying breath test at baseline, 3 and 12 months into the study. We reported weight loss outcomes as percent total body weight lost (%TBWL). Changes in three eating behaviour domains (Cognitive Restraint [CR], Emotional Eating [EE], Uncontrolled Eating [UE]) were assessed using the Three-Factor Eating Questionnaire (TFEQ) at 6 months. The primary outcome was the change in T1/2 (minutes) at 3 months, and secondary outcomes were changes in T1/2 at 12 months, %TBWL, and eating behaviours. We used the t-test for the analyses. Linear regression was performed to determine the association between gastric emptying and weight loss.

Results

46 patients were randomized in the study (ESG n=26; LS n=20). Baseline characteristics were similar between the two groups. Out of n=46, n=43, and n=31 subjects have reached 3 and 12 months, respectively. Three patients dropped out of the study. At 3 months, T1/2 (minutes) was delayed in the ESG group (n=24) compared to the LS group (n=19) (170.8 vs. 87.5; p<0.0001). At 12 months, T1/2 was still delayed in the ESG group (n=17) vs. control group (n=14) (133.4 vs. 87.6; p=0.0005), and delayed compared to baseline. %TBWL in the ESG group was 12.3%, 15.1% and 15.7% at 3, 6 and 12 months (p <0.01 compared to baseline), while it was 2.3%, 2.2% and 0.3% (p>0.05 compared to baseline) in the LS group. Greater delays in gastric emptying at 3 months correlated with weight loss at all time points. (Figure 1) At 6 months, significant improvements in the EE and UE domains were seen in both groups, but for CR, only significant improvements were seen in the ESG group. Percent total fasting ghrelin, GLP-1, and PYY increased at 12 months in the ESG group compared to LS control (51%, 51%, 6.3% vs. -9%, 4%, -10.5%). Only 1 SAE managed endoscopically with full recovery was reported in the ESG group.

Conclusions

ESG produces sustained physiologic alterations in appetite regulatory pathways and durable weight-loss. This provides further evidence supporting the clinical adoption of the technique as a durable and effective obesity therapy.

Ecogenomics and metabolic potential of the South Atlantic Ocean microbiome

The unique combination of depth, salinity, and water masses make the South Atlantic Ocean an ecosystem of special relevance within the global ocean. Yet, the microbiome of this ecosystem has received less attention than other regions of the global Ocean. This has hampered our understanding of the diversity and metabolic potential of the microorganisms that dwell in this habitat. To fill this knowledge gap, we analyzed a collection of 31 metagenomes from the Atlantic Ocean that spanned the epipelagic, mesopelagic and bathypelagic zones (surface to 4000 m). Read-centric and gene-centric analysis revealed the unique taxonomic and functional composition of metagenomes from each depth zone, which was driven by differences in physical and chemical parameters. In parallel, a total of 40 metagenome-assembled genomes were obtained, which recovered one third of the total community. Phylogenomic reconstruction revealed that many of these genomes are derived from poorly characterized taxa of Bacteria and Archaea. Genomes derived from heterotrophic bacteria of the aphotic zone displayed a large apparatus of genes suited for the utilization of recalcitrant organic compounds such as cellulose, chitin and alkanes. In addition, we found genomic evidence suggesting that mixotrophic bacteria from the bathypelagic zone could perform carbon fixation through the Calvin-Benson-Bassham cycle, fueled by sulfur oxidation. Finally, we found that the viral communities shifted throughout the water column regarding their targeted hosts and virus-to-microbe ratio, in response to shifts in the composition and functioning their microbial counterparts. Our findings shed light on the microbial and viral drivers of important biogeochemical processes that take place in the South Atlantic Ocean.

Mussismilia braziliensis White Plague Disease Is Characterized by an Affected Coral Immune System and Dysbiosis

Infectious diseases are one of the major drivers of coral reef decline worldwide. White plague-like disease (WPL) is a widespread disease with a complex etiology that infects several coral species, including the Brazilian endemic species Mussismilia braziliensis. Gene expression profiles of healthy and WPL-affected M. braziliensis were analyzed in winter and summer seasons. The de novo assembly of the M. braziliensis transcriptome from healthy and white plague samples produced a reference transcriptome containing 119,088 transcripts. WPL-diseased samples were characterized by repression of immune system and cellular defense processes. Autophagy and cellular adhesion transcripts were also repressed in WPL samples, suggesting exhaustion of the coral host defenses. Seasonal variation leads to plasticity in transcription with upregulation of intracellular signal transduction, apoptosis regulation, and oocyte development in the summer. Analysis of the active bacterial rRNA indicated that Pantoea bacteria were more abundant in WPL corals, while Tistlia, Fulvivirga, and Gammaproteobacteria Ga0077536 were more abundant in healthy samples. Cyanobacteria proliferation was also observed in WPL, mostly in the winter. These results indicate a scenario of dysbiosis in WPL-affected M. braziliensis, with the loss of potentially symbiotic bacteria and proliferation of opportunistic microbes after the start of the infection process.

Modelling the influence of environmental parameters over marine planktonic microbial communities using artificial neural networks

Guanabara Bay is a tropical estuarine ecosystem that receives massive anthropogenic impacts from the metropolitan region of Rio de Janeiro. This ecosystem suffers from an ongoing eutrophication process that has been shown to promote the emergence of potentially pathogenic bacteria, giving rise to public health concerns. Although previous studies have investigated how environmental parameters influence the microbial community of Guanabara Bay, they often have been limited to small spatial and temporal gradients and have not been integrated into predictive mathematical models. Our objective was to fill this knowledge gap by building models that could predict how temperature, salinity, phosphorus, nitrogen and transparency work together to regulate the abundance of bacteria, chlorophyll and Vibrio (a potential human pathogen) in Guanabara Bay. To that end, we built artificial neural networks to model the associations between these variables. These networks were carefully validated to ensure that they could provide accurate predictions without biases or overfitting. The estimated models displayed high predictive capacity (Pearson correlation coefficients ≥0.67 and root mean square error ≤ 0.55). Our findings showed that temperature and salinity were often the most important factors regulating the abundance of bacteria, chlorophyll and Vibrio (absolute importance ≥5) and that each of these has a unique level of dependence on nitrogen and phosphorus for their growth. These models allowed us to estimate the Guanabara Bay microbiome's response to changes in environmental conditions, which allowed us to propose strategies for the management and remediation of Guanabara Bay.

Clinical Practice Update: Expert Review on Endoscopic Bariatric Therapies

BACKGROUND & AIMS

Multiple endoscopic bariatric therapies (EBTs) currently are being evaluated or are in clinical use in the United States. EBTs are well positioned to fill an important gap in the management of obesity and metabolic disease. The purpose of this expert review is to update gastroenterologists on these therapies and provide practice advice on how to incorporate them into clinical practice.

METHODS

The evidence reviewed in this work is a distillation of comprehensive search of several English-language databases and a manual review of relevant publications (including systematic reviews and meeting abstracts). Best Practice Advice 1: EBTs should be considered in patients with obesity who have been unsuccessful in losing or maintaining weight loss with lifestyle interventions. Best Practice Advice 2: EBTs can be used in patients with severe obesity as a bridge to traditional bariatric surgery. They also can be used as a bridge to allow unrelated interventions that are unable to be performed because of weight limits (ie, orthopedic surgery, organ transplantation). Best Practice Advice 3: Clinicians should use EBTs as part of a structured weight loss program that includes dietary intervention, exercise therapy, and behavior modification, in both the active weight loss phase and the long-term maintenance phase. Best Practice Advice 4: Clinicians should screen all potential EBT candidates with a comprehensive evaluation for medical conditions, comorbidities, and psychosocial or behavioral patterns that contribute to their condition before enrolling patients in a weight loss program that includes EBTs. Best Practice Advice 5: Clinicians incorporating EBTs into their clinical practice should follow up patients prospectively to capture the impact of the EBT program on weight and weight-related comorbidities, and all related adverse outcomes. Poor responders should be identified and offered a detailed evaluation and alternative therapy. Best Practice Advice 6: Clinicians embarking on incorporating EBTs into their clinical practice should have a comprehensive knowledge of the indications, contraindications, risks, benefits, and outcomes of individual EBTs, as well as a practical knowledge of the risks and benefits of alternative therapies for obesity. Best Practice Advice 7: Institutions should establish specific guidelines that are applied consistently across disciplines for granting privileges in EBTs that reflect the necessary knowledge and technical skill a clinician must achieve before being granted privileges to perform these procedures.

Proposal of fifteen new species of Parasynechococcus based on genomic, physiological and ecological features

Members of the recently proposed genus Parasynechococcus (Cyanobacteria) are extremely abundant throughout the global ocean and contribute significantly to global primary productivity. However, the taxonomy of these organisms remains poorly characterized. The aim of this study was to propose a new taxonomic framework for Parasynechococcus based on a genomic taxonomy approach that incorporates genomic, physiological and ecological data. Through in silico DNA-DNA hybridization, average amino acid identity, dinucleotide signatures and phylogenetic reconstruction, a total of 15 species of Parasynechococcus could be delineated. Each species was then described on the basis of their gene content, light and nutrient utilization strategies, geographical distribution patterns throughout the oceans and response to environmental parameters.

Swallowable fluorometric capsule for wireless triage of gastrointestinal bleeding

Real-time detection of gastrointestinal bleeding remains a major challenge because there does not yet exist a minimally invasive technology that can both i) monitor for blood from an active hemorrhage and ii) uniquely distinguish it from blood left over from an inactive hemorrhage. Such a device would be an important tool for clinical triage. One promising solution, which we have proposed previously, is to inject a fluorescent dye into the blood stream and to use it as a distinctive marker of active bleeding by monitoring leakage into the gastrointestinal tract with a wireless fluorometer. This paper reports, for the first time to our knowledge, the development of a swallowable, wireless capsule with a built-in fluorometer capable of detecting fluorescein in blood, and intended for monitoring gastrointestinal bleeding in the stomach. The embedded, compact fluorometer uses pinholes to define a microliter sensing volume and to eliminate bulky optical components. The proof-of-concept capsule integrates optics, low-noise analog sensing electronics, a microcontroller, battery, and low power Zigbee radio, all into a cylindrical package measuring 11 mm × 27 mm and weighing 10 g. Bench-top experiments demonstrate wireless fluorometry with a limit-of-detection of 20 nM aqueous fluorescein. This device represents a major step towards a technology that would enable simple, rapid detection of active gastrointestinal bleeding, a capability that would save precious time and resources and, ultimately, reduce complications in patients.

Evaluation of an endoscopic suturing device for transoral outlet reduction in patients with weight regain following Roux-en-Y gastric bypass

BACKGROUND AND STUDY AIMS

A dilated gastrojejunal anastomosis (GJA) is thought to be associated with weight regain in patients with Roux-en-Y gastric bypass (RYGB). Due to a high rate of perioperative morbidity, surgical revision is not generally performed. The aim of this study was to assess the technical feasibility, safety, and early outcomes of a procedure using a commercially available endoscopic suturing device to reduce the diameter of the GJA.

PATIENTS AND METHODS

This was a retrospective analysis of 25 consecutive patients who underwent transoral outlet reduction (TORe) for dilated GJA and weight regain. An endoscopic suturing device was used to place sutures at the margin of the GJA in order to reduce its aperture. On chart review, clinical data were available at 3, 6, and 12 months.

RESULTS

Patients had regained a mean of 24 kg from their weight loss nadir and had a mean body mass index of 43 kg/m2 at the time of endoscopic revision. Average anastomosis diameter was 26.4 mm. Technical success was achieved in all patients (100 %) with a mean reduction in anastomosis diameter to 6 mm (range 3 - 10 mm), representing a 77.3 % reduction. The mean weight loss in successful cases was 11.5 kg, 11.7 kg, and 10.8 kg at 3, 6, and 12 months, respectively. There were no major complications.

CONCLUSION

This case series demonstrated the technical feasibility, safety, and efficacy of performing gastrojejunostomy reduction using a commercially available endoscopic suturing device. This technique may represent an effective and minimally invasive option for the management of weight regain in patients with RYGB.

Real-time computed tomography-based augmented reality for natural orifice transluminal endoscopic surgery navigation

BACKGROUND

Natural orifice transluminal endoscopic surgery (NOTES) is technically challenging owing to endoscopic short-sighted visualization, excessive scope flexibility and lack of adequate instrumentation. Augmented reality may overcome these difficulties. This study tested whether an image registration system for NOTES procedures (IR-NOTES) can facilitate navigation.

METHODS

In three human cadavers 15 intra-abdominal organs were targeted endoscopically with and without IR-NOTES via both transgastric and transcolonic routes, by three endoscopists with different levels of expertise. Ease of navigation was evaluated objectively by kinematic analysis, and navigation complexity was determined by creating an organ access complexity score based on the same data.

RESULTS

Without IR-NOTES, 21 (11·7 per cent) of 180 targets were not reached (expert endoscopist 3, advanced 7, intermediate 11), compared with one (1 per cent) of 90 with IR-NOTES (intermediate endoscopist) (P = 0·002). Endoscope movements were significantly less complex in eight of the 15 listed organs when using IR-NOTES. The most complex areas to access were the pelvis and left upper quadrant, independently of the access route. The most difficult organs to access were the spleen (5 failed attempts; 3 of 7 kinematic variables significantly improved) and rectum (4 failed attempts; 5 of 7 kinematic variables significantly improved). The time needed to access the rectum through a transgastric approach was 206·3 s without and 54·9 s with IR-NOTES (P = 0·027).

CONCLUSION

The IR-NOTES system enhanced both navigation efficacy and ease of intra-abdominal NOTES exploration for operators of all levels. The system rendered some organs accessible to non-expert operators, thereby reducing one impediment to NOTES procedures.

Marginal ulceration after Roux-en-Y gastric bypass surgery: characteristics, risk factors, treatment, and outcomes

BACKGROUND AND STUDY AIMS

Marginal ulcers are one of the most common complications after gastric bypass. Reported incidence varies widely (0.6-16 %) and pathogenesis is unclear. The aim of the present study was to describe characteristics, risk factors, management, and outcomes of endoscopically documented ulcers.

PATIENTS AND METHODS

Data from all patients diagnosed with marginal ulcers at endoscopy between 2003 and 2010 were retrospectively reviewed.

RESULTS

A total of 103 patients with marginal ulcers presented with pain (63 %) and/or bleeding (24 %), a median of 22 months after surgery. Ulcers were located on the anastomosis (50 %) or the jejunum (40 %); sutures were visible in 35 %, and gastrogastric fistulae in 8 %. The mean pouch length was 5.6 cm. Diabetes (odds ratio [OR] 2.5; P = 0.03), smoking (OR 2.5; P = 0.02), and gastric pouch length (OR 1.2; P = 0.02) were significantly associated with marginal ulcer formation on univariate analysis; diabetes was significantly associated on multivariate analysis (OR 5.6; P = 0.003). The risk of developing a marginal ulcer decreased with time (OR 0.8; P < 0.01) and was not associated with the use of nonsteroidal anti-inflammatory drugs. At first endoscopic follow-up, 67 % of ulcers had healed. Recurrence occurred in four patients and nine patients required surgical revision.

CONCLUSIONS

The vast majority of marginal ulcers had a favorable outcome after medical treatment. However, 9 % of patients eventually required surgical revision. Therefore, endoscopic follow-up is essential. Diabetes, smoking, and long gastric pouches were significant risk factors for marginal ulcer formation, suggesting increased acid exposure and mucosal ischemia are both involved in marginal ulcer pathogenesis. Management of these factors may prove effective in managing marginal ulcers, and tailoring postoperative proton pump inhibitor therapy to patients with multiple risk factors could be effective.

NOTES spin-off for the therapeutic gastroenterologist: natural orifice surgery

Natural orifice transluminal endoscopic surgery (NOTES) has ushered in a new era in flexible endoscopy. Over the past decade, modest advances have been made in addressing the fundamental challenges of NOTES surgery including transluminal access and closure techniques, and advancement of NOTES-specific technology. Despite these encouraging initial efforts significant obstacles to widespread acceptance of NOTES as a surgical option persist. Moreover, due to the well-documented safety and efficacy of laparoscopic techniques, the question remains as to the best candidate NOTES procedure. Presently, interest has shifted from true NOTES to hybrid procedures and single incision laparoscopic surgery, due to the lure of more immediate success. Additionally, there is also a growing awareness of the potential applications of natural orifice surgery techniques to the present field of therapeutic endoscopy. Research into transluminal access and closure has born several techniques and devices that are now being explored in endoscopic procedures such as full-thickness resection, endoscopic myotomy, direct endoscopic pancreatic necrosectomy and bariatric endoscopy. Such NOTES "spin-off" procedures are expanding the armamentarium of today's therapeutic endoscopists, and a growing body of literature suggests that they will play a significant role in the evolution of therapeutic endoscopy in the future.

Changes in vegetation in northern Alaska under scenarios of climate change, 2003-2100: implications for climate feedbacks

Assessing potential future changes in arctic and boreal plant species productivity, ecosystem composition, and canopy complexity is essential for understanding environmental responses under expected altered climate forcing. We examined potential changes in the dominant plant functional types (PFTs) of the sedge tundra, shrub tundra, and boreal forest ecosystems in ecotonal northern Alaska, USA, for the years 2003-2100. We compared energy feedbacks associated with increases in biomass to energy feedbacks associated with changes in the duration of the snow-free season. We based our simulations on nine input climate scenarios from the Intergovernmental Panel on Climate Change (IPCC) and a new version of the Terrestrial Ecosystem Model (TEM) that incorporates biogeochemistry, vegetation dynamics for multiple PFTs (e.g., trees, shrubs, grasses, sedges, mosses), multiple vegetation pools, and soil thermal regimes. We found mean increases in net primary productivity (NPP) in all PFTs. Most notably, birch (Betula spp.) in the shrub tundra showed increases that were at least three times larger than any other PFT. Increases in NPP were positively related to increases in growing-season length in the sedge tundra, but PFTs in boreal forest and shrub tundra showed a significant response to changes in light availability as well as growing-season length. Significant NPP responses to changes in vegetation uptake of nitrogen by PFT indicated that some PFTs were better competitors for nitrogen than other PFTs. While NPP increased, heterotrophic respiration (RH) also increased, resulting in decreases or no change in net ecosystem carbon uptake. Greater aboveground biomass from increased NPP produced a decrease in summer albedo, greater regional heat absorption (0.34 +/- 0.23 W x m(-2) x 10 yr(-1) [mean +/- SD]), and a positive feedback to climate warming. However, the decrease in albedo due to a shorter snow season (-5.1 +/- 1.6 d/10 yr) resulted in much greater regional heat absorption (3.3 +/- 1.24 W x m(-2) x 10 yr(-1)) than that associated with increases in vegetation. Through quantifying feedbacks associated with changes in vegetation and those associated with changes in the snow season length, we can reach a more integrated understanding of the manner in which climate change may impact interactions between high-latitude ecosystems and the climate system.

Magnetic retraction in natural-orifice transluminal endoscopic surgery (NOTES): addressing the problem of traction and countertraction

BACKGROUND AND STUDY AIMS

Because of their reliance on the flexible endoscope, most current procedures in natural-orifice transluminal endoscopic surgery (NOTES) suffer from the inability to vigorously grasp and move tissue or to retract organs. We aimed to assess the use of internal and external magnets that might allow the vigorous multiaxial traction/countertraction required in more complicated NOTES procedures.

METHODS

Ex vivo and in vivo porcine model. Study components were: (1) Evaluation of force-distance relationship of this magnetic retraction system using a digital tensiometer. (2) Application of this magnetic retraction system to two procedures in the porcine model: (a) Liver retraction during transcolonic cholecystectomy in five nonsurvival pigs. Procedure time was recorded and compared to historical controls. (b) Mesh positioning for implantation into the anterior abdominal wall for ventral hernia repair in three survival pigs.

RESULTS

Over a distance of 5 cm to 0.25 cm, the magnetic force of our system increased from 3 to 90 gramforce (29.42 to 882.60 mN.) In vivo, the magnet system provided robust liver retraction, shortening the procedure time of NOTES cholecystectomy from a historical mean of 68 minutes (range 42 - 90 minutes; n = 5) to 49.6 minutes (range 33 - 61 minutes; n = 3). The magnetic system also greatly enhanced mesh positioning and stability, and these animals survived for 2 weeks without complications.

CONCLUSIONS

Our basic system provided critical liver retraction during NOTES cholecystectomy and was also instrumental in moving and stabilizing mesh for implantation during NOTES ventral hernia repair. Magnets can potentially provide the vigorous traction and countertraction required to advance NOTES procedures.

Transluminal closure for NOTES: an ex vivo study comparing leak pressures of various gastrotomy and colotomy closure modalities

BACKGROUND AND STUDY AIMS

Transluminal closure is fundamental to the safe introduction of natural orifice transluminal endoscopic surgery (NOTES) into humans. Suture, staples, and clips have been used. We aimed to evaluate the acute strength of various gastrotomy and colotomy closure techniques in an ex vivo porcine model by assessing air leak pressures.

PATIENTS AND METHODS

The following closure modalities were assessed with at least five samples per arm: conventional open/laparoscopic suturing techniques including full-thickness interrupted sutures, double-layer sutures, and purse-string sutures, as well as endoscopic clips and endoscopic staples. Historical values for transgastric closures with hand-sewn interrupted sutures, endoscopic clips, and a prototype endoscopic suture device were used from our laboratory's prior study.

RESULTS

Using Kruskal-Wallis analysis, the overall comparisons were significant ( P = 0.0038 for gastrotomy closure; P = 0.0018 for colotomy closure). Post hoc paired comparisons revealed that the difference between all closure arms versus negative control were significant. Significance could not be established among the various closure arms. However, trends suggested hand-sewn double-layer sutures, endoscopic staples, and both hand-sewn and endoscopically-placed purse-string sutures produced the strongest closures. Furthermore, endoscopic clips appeared sufficient for colotomy closure when ideally placed.

CONCLUSIONS

Suture (both hand-sewn and endoscopically deployed) appears to produce the strongest closures in both stomach and colon, with the important caveats that (1) a continuous through-thickness suture track be avoided, such as in the full-thickness closure, or (2) suture holes be buried, such as in the purse-string configuration. When suture tracks are full-thickness, they can serve as leak sites. Staples and clips can produce comparable closures, but only under ideal conditions.

Transcolonic ventral wall hernia mesh fixation in a porcine model

BACKGROUND AND STUDY AIMS

A natural orifice transluminal endoscopic surgery (NOTES) approach to ventral wall hernia repair may represent a potentially less invasive alternative to current transabdominal surgical techniques. We aimed to investigate the feasibility of using transcolonic NOTES to deliver hernia repair mesh into the peritoneal cavity, as well as the ability to manipulate composite mesh and secure it to the abdominal wall.

METHODS

Five pigs weighing 20 to 25 kg were used in this feasibility study involving two acute and three survival experiments. A prototype mesh delivery system was used to transfer 1.5 - 2-cm x 2.5 - 3-cm pieces of composite hernia mesh into the peritoneal cavity. Neodymium magnets on a prototype control arm were used to help position the mesh by magnetically engaging previously placed endoscopic clips. Transfascial fixation of the mesh with 3-0 monofilament sutures was achieved using a 19-gauge hollow needle, pusher wire, and a suture tag system.

RESULTS

Composite hernia mesh was successfully transferred and secured in 5/5 attempts. All three survival animals thrived for 14 days prior to elective sacrifice. At necropsy, the mesh sites were found to be well peritonealized without adhesions. Suture placement through the posterior fascia was confirmed in 10/12 sutures. Of these, four sutures were within the abdominal musculature, and two sutures were through the anterior fascia (transfascial).

CONCLUSIONS

Transcolonic delivery, transcutaneous magnetic manipulation, and fixation of composite hernia mesh are technically feasible in a porcine model with animal survival. An effective suturing method that allows consistent anchoring through the anterior fascia would be preferred and may require the development of novel devices.

Dual-port distal pancreatectomy using a prototype endoscope and endoscopic stapler: a natural orifice transluminal endoscopic surgery (NOTES) survival study in a porcine model

BACKGROUND AND STUDY AIMS

Natural orifice transluminal endoscopic surgery (NOTES) is a potentially less invasive alternative to laparoscopic surgery that may be applicable to distal pancreatectomy. We aimed to demonstrate the technical feasibility of a NOTES distal pancreatectomy in an in vivo porcine model via a combined transvaginal-transcolonic approach.

MATERIAL AND METHODS

The procedure was performed in five female Yorkshire pigs weighing approximately 30 kg each. A prototype endoscope ("R-scope"), advanced into the peritoneal cavity through an anterior colotomy, and a computer-assisted linear stapler, introduced transvaginally, were used in dissection and resection of the distal pancreas. Prone positioning was used to enhance retroperitoneal exposure. Pneumodissection was used for blunt dissection. The colotomies were closed with endoloops. Necropsies were done immediately after the procedure in the first three animals, and after 2 weeks' survival in the final two animals.

RESULTS

Distal pancreatectomy was successful in all five animals. Prone positioning was critically important for proper exposure of retroperitoneal and pelvic structures. Pneumodissection was effective for blunt dissection, and both the linear stapler and R-scope functioned smoothly. Transvaginal and transcolonic access provided similar intraperitoneal views, and the dual-lumen approach enhanced triangulation. Both survival animals thrived postoperatively. Necropsies revealed clean staple lines; closed transcolonic and transvaginal incisions; and absence of infection, hemorrhage, or fluid collections.

CONCLUSIONS

NOTES distal pancreatectomy is technically feasible in the porcine model. The transvaginal approach provides a vantage point very similar to that of the transcolonic route and holds promise as a NOTES access site, either singly or as part of a dual-lumen approach. The endoscopic linear stapler and R-scope both advance NOTES capabilities. The novel concepts of fully prone positioning, pneumodissection, and endoloop colotomy closures are introduced. Considering anatomical differences and that healthy animals were used, transferring this technique to patients with pancreatic disease might be difficult and further modifications would likely be needed.

Pancreatic cancer cells overexpress gelsolin family-capping proteins, which contribute to their cell motility

BACKGROUND

Previously, proteomic methods were applied to characterise differentially expressed proteins in microdissected pancreatic ductal adenocarcinoma cells.

AIMS

To report that CapG and a related protein, gelsolin, which have established roles in cell motility, are overexpressed in metastatic pancreatic cancer; and to describe their pattern of expression in pancreatic cancer tissue and their effect on cell motility in pancreatic cancer cell lines.

METHODS

CapG was identified by mass spectrometry and immunoblotting. CapG and gelsolin expression was assessed by immunohistochemical analysis on a pancreatic cancer tissue microarray and correlated with clinical and pathological parameters. CapG and gelsolin levels were reduced using RNA interface in Suit-2, Panc-1 and MiaPaCa-2 cells. Cell motility was assessed using modified Boyden chamber or wound-healing assays.

RESULTS

Multiple isoforms of CapG were detected in pancreatic cancer tissue and cell lines. Immunohistochemical analysis of benign (n = 44 patients) and malignant (n = 69) pancreatic ductal cells showed significantly higher CapG staining intensity in nuclear (p<0.001) and cytoplasmic (p<0.001) compartments of malignant cells. Similarly, gelsolin immunostaining of benign (n = 24 patients) and malignant (n = 68 patients) pancreatic ductal cells showed higher expression in both compartments (both p<0.001). High nuclear CapG was associated with increased tumour size (p = 0.001). High nuclear gelsolin was associated with reduced survival (p = 0.01). Reduction of CapG or gelsolin expression in cell lines by RNAi was accompanied by significantly impaired motility.

CONCLUSIONS

Up regulation of these actin-capping proteins in pancreatic cancer and their ability to modulate cell motility in vitro suggest their potentially important role in pancreatic cancer cell motility and consequently dissemination.

Evaluating an optimal gastric closure method for transgastric surgery

BACKGROUND

The transgastric approach is currently being studied as a potentially less invasive alternative to conventional laparoscopy for intra-abdominal surgery. A major obstacle to overcome is the closure of the transgastric incision in a rapid, reproducible, and safe manner. The effectiveness of various techniques for gastrotomy closure were compared by assessing leak pressures in an ex vivo porcine stomach model.

METHODS

Whole stomachs from adult white pigs were suspended in a Plexiglas box to facilitate endoscopic technique. Standard gastrotomies were made by needle knife incision and dilation with a controlled radial expansion (CRE) balloon. The first arm used standard QuickClips; the second, a prototype device developed by LSI Solutions; the third, hand-sewn by a senior surgeon; the final, a control with open gastrotomy. Five stomachs were tested per study arm. After closure, each stomach was inflated by an automated pressure gauge. The pressures to achieve air leakage and liquid leakage were recorded.

RESULTS

The unclosed controls demonstrated air leakage at a median pressure of 15 mmHg, representing baseline system resistance. The QuickClip closures leaked air at a median pressure of 33 mmHg. The prototype gastrotomy device yielded the highest median air leak pressure of 85 mmHg while dramatically diminishing time for incision and gastrotomy closure to approximately 5 min. The hand-sewn closures leaked air at a median pressure of 47 mmHg. Using Kruskal-Wallis statistical analysis, the comparisons were significant (p = 0.0019). Post hoc paired comparisons using MULTTEST procedure with both Bonferroni and bootstrap adjustments revealed that the difference between prototype and clips was significant; prototype versus hand-sewn was not. Liquid-leak pressures produced similar results.

CONCLUSIONS

The prototype device decreases procedure time and yields leak-resistant gastrotomy closures that are superior to clips and rival hand-sewn interrupted stitches.

Peroral endoscopic reduction of dilated gastrojejunal anastomosis after Roux-en-Y gastric bypass: a possible new option for patients with weight regain

BACKGROUND

Roux-en-Y gastric bypass (RYGB) is an effective treatment for severe obesity. However, many patients regain weight over time. The mechanisms for this are unclear, and several factors may contribute, including dilation of the gastrojejunal anastomosis. This study aimed to assess the feasibility of endoscopic gastrojejunal anastomotic tightening and to determine the effect of tightening on body weight.

METHODS

Eight patients with significant weight regain and dilated gastrojejunal anastomosis after RYGB were included in this pilot study. Sutures were placed endoscopically at the rim of the anastomosis. When tightened, the sutures formed tissue placations, reducing the size of the anastomotic aperture.

RESULTS

The average preprocedure body mass index (BMI) was 40.5, and the patients had regained a mean of 24 kg from their post-RYGB nadir. The average pouch length was 5.7 cm, and the average anastomotic diameter was 25 mm. The average postreduction diameter was 10.0 mm (68% reduction). Six of the eight patients showed weight loss (mean, 10 kg) at 4 months. Repeat procedures were performed for three patients who had lost 4, 5, and 9 kg, respectively with the initial procedure. After the second anastomotic reduction, the final diameters were, respectively, 14, 5, and 5 mm. The first patient did not have further weight loss. The remaining two patients showed a total weight loss of 19 and 20 kg, respectively, at 5 months. All 11 reductions were accomplished without significant complication. The average postreduction BMI was 37.7, and the percentage of excess weight loss was 23.4%.

CONCLUSION

Peroral endoscopic suturing to tighten dilated gastrojejunal anastomoses appears technically feasible and safe. This procedure is associated with variable but significant weight loss, and preliminary results suggest that it may offer a new treatment option for postbypass weight regain in selected patients.

Phylogeny and molecular identification of vibrios on the basis of multilocus sequence analysis

We analyzed the usefulness of rpoA, recA, and pyrH gene sequences for the identification of vibrios. We sequenced fragments of these loci from a collection of 208 representative strains, including 192 well-documented Vibrionaceae strains and 16 presumptive Vibrio isolates associated with coral bleaching. In order to determine the intraspecies variation among the three loci, we included several representative strains per species. The phylogenetic trees constructed with the different genetic loci were roughly in agreement with former polyphasic taxonomic studies, including the 16S rRNA-based phylogeny of vibrios. The families Vibrionaceae, Photobacteriaceae, Enterovibrionaceae, and Salinivibrionaceae were all differentiated on the basis of each genetic locus. Each species clearly formed separated clusters with at least 98, 94, and 94% rpoA, recA, and pyrH gene sequence similarity, respectively. The genus Vibrio was heterogeneous and polyphyletic, with Vibrio fischeri, V. logei, and V. wodanis grouping closer to the Photobacterium genus. V. halioticoli-, V. harveyi-, V. splendidus-, and V. tubiashii-related species formed groups within the genus Vibrio. Overall, the three genetic loci were more discriminatory among species than were 16S rRNA sequences. In some cases, e.g., within the V. splendidus and V. tubiashii group, rpoA gene sequences were slightly less discriminatory than recA and pyrH sequences. In these cases, the combination of several loci will yield the most robust identification. We can conclude that strains of the same species will have at least 98, 94, and 94% rpoA, recA, and pyrH gene sequence similarity, respectively.

Phylogeny and identification of Enterococci by atpA gene sequence analysis

The relatedness among 91 Enterococcus strains representing all validly described species was investigated by comparing a 1,102-bp fragment of atpA, the gene encoding the alpha subunit of ATP synthase. The relationships observed were in agreement with the phylogeny inferred from 16S rRNA gene sequence analysis. However, atpA gene sequences were much more discriminatory than 16S rRNA for species differentiation. All species were differentiated on the basis of atpA sequences with, at a maximum, 92% similarity. Six members of the Enterococcus faecium species group (E. faecium, E. hirae, E. durans, E. villorum, E. mundtii, and E. ratti) showed > 99% 16S rRNA gene sequence similarity, but the highest value of atpA gene sequence similarity was only 89.9%. The intraspecies atpA sequence similarities for all species except E. faecium strains varied from 98.6 to 100%; the E. faecium strains had a lower atpA sequence similarity of 96.3%. Our data clearly show that atpA provides an alternative tool for the phylogenetic study and identification of enterococci.

Photobacterium rosenbergii sp. nov. and Enterovibrio coralii sp. nov., vibrios associated with coral bleaching

Six new Vibrio-like isolates originating from different species of bleached and healthy corals around Magnetic Island (Australia) were investigated using a polyphasic approach. Phylogenetic analyses based on 16S rRNA, recA and rpoA gene sequences split the isolates in two new groups. Strains LMG 22223(T), LMG 22224, LMG 22225, LMG 22226 and LMG 22227 were phylogenetic neighbours of Photobacterium leiognathi LMG 4228(T) (95.6 % 16S rRNA gene sequence similarity), whereas strain LMG 22228(T) was related to Enterovibrio norvegicus LMG 19839(T) (95.5 % 16S rRNA gene sequence similarity). The two new groups can be distinguished from closely related species on the basis of several phenotypic features, including fermentation of d-mannitol, melibiose and sucrose, and utilization of different compounds as carbon sources, arginine dihydrolase activity, nitrate reduction, resistance to the vibriostatic agent O/129 and the presence of fatty acids 15 : 0 iso and 17 : 0 iso. The names Photobacterium rosenbergii sp. nov. (type strain LMG 22223(T)=CBMAI 622(T)=CC1(T)) and Enterovibrio coralii sp. nov. (type strain LMG 22228(T)=CBMAI 623(T)=CC17(T)) are proposed to accommodate these new isolates. The G+C contents of the DNA of the two type strains are respectively 47.6 and 48.2 mol%.

Use of recA as an alternative phylogenetic marker in the family Vibrionaceae

This study analysed the usefulness of recA gene sequences as an alternative phylogenetic and/or identification marker for vibrios. The recA sequences suggest that the genus Vibrio is polyphyletic. The high heterogeneity observed within vibrios was congruent with former polyphasic taxonomic studies on this group. Photobacterium species clustered together and apparently nested within vibrios, while Grimontia hollisae was apart from other vibrios. Within the vibrios, Vibrio cholerae and Vibrio mimicus clustered apart from the other genus members. Vibrio harveyi- and Vibrio splendidus-related species formed compact separated groups. On the other hand, species related to Vibrio tubiashii appeared scattered in the phylogenetic tree. The pairs Vibrio coralliilyticus and Vibrio neptunius, Vibrio nereis and Vibrio xuii and V. tubiashii and Vibrio brasiliensis clustered completely apart from each other. There was a correlation of 0·58 between recA and 16S rDNA pairwise similarities. Strains of the same species have at least 94 % recA sequence similarity. recA gene sequences are much more discriminatory than 16S rDNA. For 16S rDNA similarity values above 98 % there was a wide range of recA similarities, from 83 to 99 %.

Vibrio hispanicus sp. nov., isolated from Artemia sp. and sea water in Spain

Three Gram-negative, small, motile, rod-shaped bacteria were isolated from Artemia sp. and sea water in Barcelona, Spain, during 1990 and 1991. They were fermentative, oxidase-positive, sensitive to vibriostatic agent O/129, arginine dihydrolase-positive, lysine and ornithine decarboxylase-negative and grew in the absence of NaCl. They differed from phenotypically related species by their ability to grow at 4 °C and utilize l-rhamnose. Cloning of the 16S rRNA gene of the type strain produced two different 16S rRNA gene sequences, which differed by 15 bases (0·99 %); comparison of these sequences with those deposited in GenBank showed close relationships with Vibrio proteolyticus (97·6 % similarity), Vibrio diazotrophicus (97·9 %), Vibrio campbellii (96·8 %) and Vibrio alginolyticus (96·8 %), among others. DNA–DNA hybridization levels with the closest phylogenetically related Vibrio species were <26·4 %. Sufficient evidence is provided to support the identity of the three strains analysed as members of a novel species of the genus Vibrio, for which the name Vibrio hispanicus sp. nov. is proposed, with the type strain LMG 13240T (=CAIM 525T=VIB 213T).

Vibrio fortis sp. nov. and Vibrio hepatarius sp. nov., isolated from aquatic animals and the marine environment

In this study, the taxonomic positions of 19 Vibrio isolates disclosed in a previous study were evaluated. Phylogenetic analysis based on 16S rDNA sequences partitioned these isolates into groups that were closely related (98.8-99.1 % similarity) to Vibrio pelagius and Vibrio xuii, respectively. DNA-DNA hybridization experiments further showed that these groups had <70 % similarity to other Vibrio species. Two novel Vibrio species are proposed to accommodate these groups: Vibrio fortis sp. nov. (type strain, LMG 21557(T)=CAIM 629(T)) and Vibrio hepatarius sp. nov. (type strain, LMG 20362(T)=CAIM 693(T)). The DNA G+C content of both novel species is 45.6 mol%. Useful phenotypic features for discriminating V. fortis and V. hepatarius from other Vibrio species include production of indole and acetoin, utilization of cellobiose, fermentation of amygdalin, melibiose and mannitol, beta-galactosidase and tryptophan deaminase activities and fatty acid composition.

Vibrio pacinii sp. nov., from cultured aquatic organisms

Three strains were isolated from cultured aquatic organisms. They were Gram-negative, oxidase-positive, motile, fermentative, arginine dihydrolase-positive, lysine and ornithine decarboxylase-negative and sensitive to vibriostatic agent O/129. These strains differ from other related Vibrio species by several phenotypic features, which include acetoin and indole production and utilization of amygdalin and D-mannitol. Comparison of 16S rDNA sequences showed a close relationship to the recently described species Vibrio kanaloae (96.6 %) and Vibrio pomeroyi (96.4 %) and to Vibrio furnissii (96.6 %), but DNA-DNA hybridization experiments showed that the three isolates form a tight novel species with </=30 % DNA-DNA similarity to its closest phylogenetic neighbours. Vibrio pacinii sp. nov. is proposed, with LMG 19999(T) (=CAIM 530(T)=STD3-1057(T); DNA G+C content, 44.9 mol%) as the type strain.

Vibrio kanaloae sp. nov., Vibrio pomeroyi sp. nov. and Vibrio chagasii sp. nov., from sea water and marine animals

The taxonomic position of the fluorescent amplified fragment length polymorphism fingerprinting groups A46 (five isolates), A51 (six isolates), A52 (five isolates) and A53 (seven isolates) obtained in a previous study were further analysed through a polyphasic approach. The 23 isolates were phylogenetically related to Vibrio splendidus, but DNA-DNA hybridization experiments proved that they belong to three novel species. Chemotaxonomic and phenotypic analyses further disclosed several features that differentiate between the 23 isolates and known Vibrio species. The names Vibrio kanaloae sp. nov. (type strain LMG 20539(T) = CAIM 485(T); EMBL accession no. AJ316193; G + C content 44.7 mol%), Vibrio pomeroyi sp. nov. (type strain LMG 20537(T) = CAIM 578(T); EMBL accession no. AJ491290; G +C content 44.1 mol%) and Vibrio chagasii sp. nov. (type strain LMG 21353(T) = CAIM 431(T); EMBL accession no. AJ316199; G + C content 44.6 mol%) are respectively proposed to encompass the five isolates of A46, the six isolates of A51 and the 12 isolates of A52/A53. The three novel species can be distinguished from known Vibrio species by several phenotypic features, including utilization and fermentation of various carbon sources, beta-galactosidase activity and fatty acid content (particularly of 12 : 0, 14: 0, 14 : 0 iso and 16 : 0 iso).

Vibrio tasmaniensis sp. nov., isolated from Atlantic salmon (Salmo salar L.)

We describe the polyphasic characterization of four Vibrio isolates which formed a tight AFLP group in a former study. The group was closely related to V. cyclitrophicus, V. lentus and V. splendidus (98.2-98.9% similarity) on the basis of the 16S rDNA sequence analysis, but by DNA-DNA hybridisation experiments it had at maximum 61% DNA similarity towards V. splendidus. Thus, we propose that the isolates represent a new Vibrio species i.e. V. tasmaniensis (LMG 20012T; EMBL under the accession numbers AJ316192; mol% G+C of DNA of the type strain is 44.7). Useful phenotypical features for discrimination of V. tasmaniensis from other Vibrio species include gelatinase and beta-galactosidase activity, fatty acid composition (particularly 14:0), utilisation and fermentation of different compounds (e.g. sucrose, melibiose and D-galactose) as sole carbon source.

Vibrio rotiferianus sp. nov., isolated from cultures of the rotifer Brachionus plicatilis

Five Gram-negative bacterial strains, oxidase-positive, motile by means of more than one polar flagella, facultative anaerobe, arginine dihydrolase-negative, lysine- and omithine decarboxylase-positive, sensitive to the vibriostatic agent O/129, were isolated from a flow-through rotifer culture system in Gent, Belgium, and previously characterized by fluorescent amplified fragment length polymorphism. Comparison of the 16S rDNA sequence of strain LMG 21460T indicated close relationships (approximately 99% similarity) to Vibrio campbellii, Vibrio harveyi, Vibrio alginolyticus and Vibrio parahaemolyticus. However, DNA hybridization experiments revealed similarity values below 70% with its closest species V. campbellii and V. harveyi. Additionally, the analysed strains differ from related Vibrio species by the utilization of melibiose and production of acid from L-arabinose and amygdalin. Among the strains analysed, differences were observed in some phenotypic characters, particularly susceptibility to ampicillin, polymyxin B and amikacin, and urease activity. The major fatty acids identified were 16:0, 18:1 omega7c, 14:0, 12:0 3-OH and 18:0. Vibrio rotiferianus sp. nov. is proposed, with type strain LMG 21460T (=CAIM 577T); it has a DNA G+C content of 44.5 +/- 0.01 mol%.

Vibrio coralliilyticus sp. nov., a temperature-dependent pathogen of the coral Pocillopora damicornis

Vibrio sp. YB1T (=ATCC BAA-450T =LMG 20984T), the aetiological agent of tissue lysis of the coral Pocillopora damicornis, was characterized as a novel Vibrio species on the basis of 16S rDNA sequence, DNA-DNA hybridization data (G + C content is 45.6 mol%), AFLP and GTG5-PCR genomic fingerprinting patterns and phenotypic properties, including the cellular fatty acid profile. The predominant fatty acids were 16:0 and 18:1 omega7c. The name Vibrio coralliilyticus sp. nov. is proposed for the novel coral-pathogenic species. In addition to strain YB1T, which was isolated from the Indian Ocean, five additional strains of V. coralliilyticus have been isolated, three from diseased P. damicornis in the Red Sea, one from diseased oyster larvae (Kent, UK) and one from bivalve larvae (Brazil). The six V. coralliilyticus strains showed high genotypic and phenotypic similarities and all were pathogenic to P. damicornis. The closest phylogenetic neighbours to V. coralliilyticus are Vibrio tubiashii, Vibrio nereis and Vibrio shilonii.

Vibrio neptunius sp. nov., Vibrio brasiliensis sp. nov. and Vibrio xuii sp. nov., isolated from the marine aquaculture environment (bivalves, fish, rotifers and shrimps)

The fluorescent amplified fragment length polymorphism (FAFLP) groups A5 (21 isolates), A8 (6 isolates) and A23 (3 isolates) distinguished in an earlier paper (Thompson et al., Syst Appl Microbiol 24, 520-538, 2001) were examined in more depth. These three groups were phylogenetically related to Vibrio tubiashii, but DNA-DNA hybridization experiments proved that the three AFLP groups are in fact novel species. Chemotaxonomic and phenotypic analyses further revealed several differences among the 30 isolates and known Vibrio species. It is proposed to accommodate these isolates in three novel species, namely Vibrio neptunius (type strain LMG 20536T; EMBL accession no. AJ316171; G +C content of the type strain 46.0 mol%), Vibrio brasiliensis (type strain LMG 20546T; EMBL accession no. AJ316172; G + C content of the type strain 45.9 mol%) and Vibrio xuii (type strain LMG 21346T; EMBL accession no. AJ316181; G +C content of the type strain 46.6 mol%). These species can be differentiated on the basis of phenotypic features, including fatty acid composition (particularly 14:0 iso, 14:0 iso 3-OH, 16:0 iso, 16:0, 17:0 and 17:1 omega8c), enzyme activities and utilization and fermentation of various carbon sources.

Enterovibrio norvegicus gen. nov., sp. nov., isolated from the gut of turbot (Scophthalmus maximus) larvae: a new member of the family Vibrionaceae

Twenty-two isolates originating from the gut of healthy cultured turbot larvae in Norway were investigated using a polyphasic approach. Amplified fragment length polymorphism fingerprinting analysis showed that the isolates have typical patterns and form two main groups. Phylogenetic analysis revealed that the isolates belong to the gamma-Proteobacteria, with Vibrio hollisae as their closest neighbour. DNA-DNA hybridization, chemotaxonomic and phenotypic analyses further proved that these isolates represent a tight novel taxon that differs from currently described species in the family Vibrionaceae. It is proposed that these novel isolates be accommodated in a new genus, Enterovibrio gen. nov., with Enterovibrio norvegicus sp. nov. as the type species. Isolates were motile by a polar flagellum, positive for oxidase, catalase, arginine dihydrolase and beta-galactosidase, but negative for the Voges-Proskauer reaction. They produced indole, did not reduce nitrate and were resistant to the vibriostatic agent O/129. The DNA G+C content of E. norvegicus was 47.1-47.9 mol%. The type strain is E. norvegicus LMG 19839(T) (= CAIM 430(T)).

Microscopic localization of active gelatinases in equine osteochondritis dissecans (OCD) cartilage

OBJECTIVE

To investigate the relationship between matrix metalloproteinase (MMP) activity and osteochondritis dissecans (OCD) in the equine joint.

METHODS

Equine articular cartilage was obtained from normal (N = 8) and osteochondrotic (OCD) (N = 6) femoropatellar joints from horses at necropsy. The activity of gelatinase MMPs was determined in sections of cartilage by in situ gelatin zymography.

RESULTS

Gelatinase activity was markedly increased in articular cartilage obtained from OCD samples and was particularly prominent in the deep cartilage zone. Activity was only seen in the pericellular area of chondrocytes. In addition, in OCD cartilage there were vertical lines of activity, starting from the deep zone and radiating towards the articular surface. In contrast, normal cartilage showed only a very small amount of gelatinolytic activity, which was not restricted to specific cartilage zones. Gelatin zymography of culture supernatants from isolated chondrocytes demonstrated increased production of MMP-2 and MMP-9 from OCD chondrocytes.

CONCLUSIONS

Sections of articular cartilage from OCD lesions revealed MMP activity, especially in the deep zone adjacent to the calcified subchondral bone. This MMP activity could account for the loss of cartilage integrity in the deep cartilage zone and the vertical lines of activity could represent areas of mechanical weakness, likely to result in fissures and the release of cartilage fragments into the joint space.

The coral bleaching Vibrio shiloi Kushmaro et al. 2001 is a later synonym of Vibrio mediterranei Pujalte and Garay 1986

The coral bleaching Vibrio shiloi LMG 19703T was characterized by means of Fluorescent Amplified Fragment Length Polymorphism (FAFLP), DNA-DNA hybridisation, mol% G+C content, fatty acids methyl ester (FAME) analysis and phenotypical tests. Numerical analysis of the FAFLP band patterns indicated that the type strain of V. shiloi in fact belongs to the species V. mediterranei. The type strains of both species shared 77% DNA similarity, as determined by DNA-DNA hybridisation experiments at stringent conditions. Moreover, V. shiloi and V. mediterranei showed almost identical fatty acid composition and phenotypical features. Collectively, the genotypic and phenotypic data presented in this study suggest that V. shiloi Kushmaro et al. 2001 should be considered a later synonym of V. mediterranei Pujalte and Garay 1986. The involvement of V. mediterranei in coral bleaching was unknown until now.

The hairless gene mutated in congenital hair loss disorders encodes a novel nuclear receptor corepressor

The mammalian hairless (hr) gene plays a critical role in the maintenance of hair growth. Although the hr gene has been identified, the biochemical function of its encoded protein (Hr) has remained obscure. Here, we show that Hr functions as a transcriptional corepressor for thyroid hormone receptors (TRs). We find that two independent regions of Hr mediate TR binding and that interaction requires a cluster of hydrophobic residues similar to the binding motifs proposed for nuclear receptor corepressors (N-CoR and SMRT). Similarly, we show that Hr binds to the same region of TR as known corepressors. We show that Hr interacts with histone deacetylases (HDACs) and is localized to matrix-associated deacetylase (MAD) bodies, indicating that the mechanism of Hr-mediated repression is likely through associated HDAC activity. Thus, Hr is a component of the corepressor machinery, and despite its lack of sequence identity with previously described corepressors, its mode of action is remarkably conserved. On the basis of its thyroid hormone-inducible and tissue- and developmental-specific expression, Hr likely defines a new class of nuclear receptor corepressors that serve a more specialized role than ubiquitous corepressors. The discovery that Hr is a corepressor provides a molecular basis for specific hair loss syndromes in both humans and mice.

Neuronal expression of synaptotagmin-related gene 1 is regulated by thyroid hormone during cerebellar development

Thyroid hormone (TH) is essential for proper brain development, acting through nuclear receptors that modulate the expression of specific genes in response to hormone binding. In a screen for genes regulated by TH in the rat cerebellum, we recently identified a novel gene, synaptotagmin-related gene 1 (Srg1). The Srg1 protein is structurally similar to synaptotagmins, a family of proteins involved in regulating neurotransmission. To elucidate a potential role of Srg1 in brain development, we have investigated the developmental and TH-regulated expression of Srg1 in the neonatal rat brain. We show that expression of both Srg1 RNA and protein is detected only in the brain and specifically in neurons. Srg1 mRNA and protein levels increase postnatally, nearing adult levels after the third postnatal week. Neonatal TH deficiency results in a significant reduction and delay in expression of both Srg1 RNA and protein. Using immunohistochemistry, we were able to detect Srg1 protein in numerous brain regions. In the cerebellum, Srg1 protein is localized to the molecular layer, indicating that it is highly expressed in granule cell axons. To further examine Srg1 expression in cerebellar granule cells (CGCs), we used an in vitro cell culture model. In primary cultures of CGCs, Srg1 expression is significantly reduced in the absence of TH. Srg1 mRNA is rapidly upregulated in cultured CGCs, suggesting a direct response to TH. Neuronal and TH-regulated expression of Srg1, together with its localization to neurites, implicates Srg1 as an important component of the program of gene expression induced by TH in the developing brain.

Differential regulation of gelatinases by transforming growth factor beta-1 in normal equine chondrocytes

OBJECTIVE

Cartilage destruction in osteoarthritis (OA) is associated with increased levels of several matrix metalloproteinases (MMPs), including the gelatinases MMP-2 and MMP-9. While increases in some MMPs may be destructive, up-regulation of others may result from increases in normal tissue turnover. The production of MMP-2 and MMP-9 by the anabolic transforming growth factor beta-1 (TGF-beta1) in normal equine chondrocytes was investigated.

DESIGN

Equine chondrocytes from clinically normal femoropatellar joints were maintained in alginate beads. After serum deprivation, cells were exposed to TGF-beta1 at several concentrations for varying times. Activities of MMP-2 and MMP-9 were estimated by gelatin zymography, while mRNA for MMP-2, MMP-9 and collagen type II were detected using reverse transcription-polymerase chain reaction.

RESULTS

Stimulation with TGF-beta1 differentially regulated MMP-2 and MMP-9, with strong up-regulation of both MMP-9 mRNA and enzyme. Increases in MMP-9 enzyme were dose-dependent (0-49 h). There is some evidence suggesting a slight reduction in MMP-2 release following stimulation. Collagen type II mRNA was transiently increased following stimulation.

CONCLUSIONS

The different effects of TGF-beta1 on MMP-2 and MMP-9 production by normal chondrocytes suggests different roles for these enzymes. The increases in both MMP-9 and collagen type II mRNA following stimulation may suggest a role for MMP-9 in tissue maintenance. Therefore, increased MMP-9 may be secondary to, as distinct from a cause of, cartilage damage.

Measurement of cartilage oligomeric matrix protein (COMP) in normal and diseased equine synovial fluids

OBJECTIVE

This study was designed to assay cartilage oligomeric matrix protein (COMP) in equine synovial fluids and to compare the concentration in synovial fluids from normal horses with joint diseased horses. The relationship between the COMP degradation and the matrix metalloproteinase activity in synovial fluids was also investigated.

DESIGN

Using COMP antigen prepared from equine articular cartilage and murine monoclonal antibody (12C4) raised against human COMP, an inhibition ELISA was developed. COMP in equine synovial fluids from normal and diseased joints was quantified. Metalloproteinase activities were evaluated in the same synovial fluids by a gelatin degradation ELISA. COMP fragments were evaluated qualitatively by Western blotting.

RESULTS

The COMP inhibition ELISA was reliable at concentrations of equine COMP between 62.5 and 2000 ng/ml. COMP values in joint fluids in both aseptic and septic joint disease (19.7+/-15.3 and 16.1+/-11.2 microg/ml, respectively) were significantly (P < 0.001) lower than normal (53.2+/-29.0 microg/ml). The molecular sizes of COMP on immunoblots were different between normal and diseased synovial fluids; more fragments were seen in diseased fluids. The aseptic (26.6 +/- 20.6%) and septic joint disease synovial fluids (36.1 +/- 37.5%) had significantly higher (P < 0.02 and 0.002, respectively) gelatinolytic activities than normal (13.6 +/- 13.7%). There was a negative correlation (R = -0.31, P < 0.002) between COMP level and gelatinase activity. Conclusions We conclude that the fragment pattern and the absolute COMP concentration maybe useful for monitoring joint disease, and that COMP degradation in synovial fluids from progressed joint disease may be due to MMP gelatinolytic activity.

Thyroid hormone action in neural development

Effects of thyroid hormone on development of the brain have been documented for over a century. Although in many respects the hypothyroid brain appears morphologically normal, functional impairments include mental retardation, ataxia and spasticity. Keyed by the discovery of nuclear receptors for thyroid hormone that function as transcription factors, recent work has examined the mechanism of thyroid hormone action in brain development. The prediction that gene expression regulated by thyroid hormone is important for mediating brain development has spurred the search for thyroid hormone-responsive genes. Here we review some of the identified genes whose expression patterns correlate with the functional deficits observed in the hypothyroid brain. Recently identified thyroid hormone-responsive genes include synaptotagmin-related gene 1 (Srg1), a putative mediator of synaptic structure and/or activity, and hairless, a transcriptional cofactor that may influence the expression of other thyroid hormone-responsive genes.

Late G1 accumulation after 2 Gy of gamma-irradiation is related to endogenous Raf-1 protein expression and intrinsic radiosensitivity in human cells

We have previously reported a correlation between high endogenous expression of the protein product of the RAF-1 proto-oncogene, intrinsic cellular radiosensitivity and rapid exit from a G2/M delay induced by 2 Gy of gamma-irradiation. Raf1 is a positive serine/threonine kinase signal transduction factor that relays signals from the cell membrane to the MAP kinase system further downstream and is believed to be involved in an ionizing radiation signal transduction pathway modulating the G1/S checkpoint. We therefore extended our flow cytometric studies to investigate relationships between radiosensitivity, endogenous expression of the Raf1 protein and perturbation of cell cycle checkpoints, leading to alterations in the G1, S and G2/M populations after 2 Gy of gamma-irradiation. Differences in intrinsic radiosensitivity after modulation of the G1/S checkpoint have generally been understood to involve p53 function up to the present time. A role for dominant oncogenes in control of G1/S transit in radiation-treated cells has not been identified previously. Here, we show in 12 human in vitro cancer cell lines that late G1 accumulation after 2 Gy of radiation is related to both Raf1 expression (r = 0.91, P = 0.0001) and the radiosensitivity parameter SF2 (r = -0.71, P = 0.009).

The product of a thyroid hormone-responsive gene interacts with thyroid hormone receptors

Thyroid hormone is a critical mediator of central nervous system (CNS) development, acting through nuclear receptors to modulate the expression of specific genes. Transcription of the rat hairless (hr) gene is highly up-regulated by thyroid hormone in the developing CNS; we show here that hr is directly induced by thyroid hormone. By identifying proteins that interact with the hr gene product (Hr), we find that Hr interacts directly and specifically with thyroid hormone receptor (TR)-the same protein that regulates its expression. Unlike previously described receptor-interacting factors, Hr associates with TR and not with retinoic acid receptors (RAR, RXR). Hr can act as a transcriptional repressor, suggesting that its interaction with TR is part of a novel autoregulatory mechanism.

Thyroid hormone-responsive genes in developing cerebellum include a novel synaptotagmin and a hairless homolog

Proper development of the mammalian CNS requires sufficient thyroid hormone; thyroid hormone deficiency during a brief perinatal period produces severe neurological defects in humans and experimental animals. Thyroid hormone exerts its effects through nuclear receptors, which modulate the transcription of downstream genes in response to hormone binding. Surprisingly, few genes that are regulated by thyroid hormone receptors in the CNS have been described. Here, I report the isolation and characterization of genes that are expressed in response to thyroid hormone in developing rat brain. One such gene (Srg1) encodes a novel protein related to synaptotagmin, a protein involved in regulating neurotransmitter release; another (hr) encodes a putative zinc finger protein related to the product of a recently identified mouse gene, hairless. Both Srg1 and hr are induced rapidly (<4 hr), suggesting that they are regulated directly by thyroid hormone. The temporal and spatial expression of both Srg1 and hr is characteristic of genes important to nervous system development. Srg1 and hr are likely part of a cascade of gene activation induced by thyroid hormone that is critical for CNS organization and development.

Exit from G2 phase after 2 Gy gamma irradiation is faster in radiosensitive human cells with high expression of the RAF1 proto-oncogene

We have previously noted that high endogenous expression of the protein product of the full-length RAF1 proto-oncogene is related to relative intrinsic cellular radiosensitivity in 19 human cells lines in vitro. This appeared to be unrelated to the parameters of cell kinetics. In rodent and human cell lines transfected with dominant oncogenes, including Myc and MYC, Hras and HRAS and SV40, increased radioresistance has been accompanied by increased delay in progress through the G2 phase of the cell cycle after irradiation. We have thus examined the putative relationship between RAF1 expression and postirradiation perturbation of G2 phase in six of the human cell lines for which data have been reported previously. These lines exhibit a wide range of both radiosensitivity and Raf1 protein levels as measured previously by Western blotting. We report here that the cell lines whose cells appear to exit more rapidly from G2 phase are more radiosensitive (r = 0.91, P = 0.01) and express high levels of Raf1 protein (r = -0.93, P = 0.006).

Accidental contamination from uranium compounds through contact with ceramic dinnerware

Examination of orange-colored dinnerware samples purchased in antique stores and flea markets has revealed the occasional presence of surface uranium compounds that are readily transferred to the hands and clothing. We have further been able to produce soluble uranium compounds on the surfaces of clean dishes by exposing them to household vinegar or bleach. We estimate that handling of a contaminated dish can transfer up to 1-2 becquerels or more of uranium compounds to the hands. Uranium contamination is of concern because the element is not only an alpha emitter but also a chemical nephrotoxin. Although the amount of uranium likely to be ingested as a result of casual handling may be small, it could still exceed by several times the amount occurring in the average diet (about 40 mBq/day). Furthermore, since fresh surface compounds are readily formed, it is possible that a person who regularly handles or eats from uranium-glazed dinnerware can accidentally ingest significant amounts of uranium.