Genome-wide association analysis of diverticular disease points towards neuromuscular, connective tissue and epithelial pathomechanisms

OBJECTIVE

Diverticular disease is a common complex disorder characterised by mucosal outpouchings of the colonic wall that manifests through complications such as diverticulitis, perforation and bleeding. We report the to date largest genome-wide association study (GWAS) to identify genetic risk factors for diverticular disease.

DESIGN

Discovery GWAS analysis was performed on UK Biobank imputed genotypes using 31 964 cases and 419 135 controls of European descent. Associations were replicated in a European sample of 3893 cases and 2829 diverticula-free controls and evaluated for risk contribution to diverticulitis and uncomplicated diverticulosis. Transcripts at top 20 replicating loci were analysed by real-time quatitative PCR in preparations of the mucosal, submucosal and muscular layer of colon. The localisation of expressed protein at selected loci was investigated by immunohistochemistry.

RESULTS

We discovered 48 risk loci, of which 12 are novel, with genome-wide significance and consistent OR in the replication sample. Nominal replication (p<0.05) was observed for 27 loci, and additional 8 in meta-analysis with a population-based cohort. The most significant novel risk variant rs9960286 is located near CTAGE1 with a p value of 2.3×10^-10 and 0.002 (OR_allelic=1.14 (95% CI 1.05 to 1.24)) in the replication analysis. Four loci showed stronger effects for diverticulitis, PHGR1 (OR 1.32, 95% CI 1.12 to 1.56), FAM155A-2 (OR 1.21, 95% CI 1.04 to 1.42), CALCB (OR 1.17, 95% CI 1.03 to 1.33) and S100A10 (OR 1.17, 95% CI 1.03 to 1.33).

CONCLUSION

In silico analyses point to diverticulosis primarily as a disorder of intestinal neuromuscular function and of impaired connective fibre support, while an additional diverticulitis risk might be conferred by epithelial dysfunction.

Global trauma: the great divide

Road trauma is an emergent global issue. There is huge disparity between the population affected by road trauma and the resource allocation. If the current trend continues, a predicted extra 5 million lives will be lost in this decade. This article aims to create an awareness of the scale of the problem of road trauma and the inequality in the resources available to address this problem. It also describes the responses from the international organisations and the orthopaedic community in dealing with this issue. The International Orthopaedic community has a unique opportunity and moral obligation to play a part in changing this trend of global trauma.

Wound healing in the tissues of the periodontium following periradicular surgery. III. The osseous excisional wound

Excisional wounds were made in the maxillas and mandibles of rhesus monkeys, and the osseous wound-healing responses at postsurgical intervals ranging from 1 to 28 days were evaluated by light microscopy. The excisional defects were initially filled with a coagulum which was subsequently replaced by granulation tissue emanating from the endosteal tissues. Cortical and trabecular bone forming the wound edges was devitalized, as evidenced by an absence of osteocytes in the peripheral lacunae. At 14 days postsurgery, woven bone trabeculae occupied most of the defect, with the more superficial trabeculae in direct contact with a thick band of dense fibrous connective tissue separating the osseous defect from overlying mucosal tissues. Within the defect, new bone was deposited on devitalized bone without evidence of preceding osteoclastic activity. At 28 days, the woven bone trabeculae were more mature and a functioning periosteum was now active in repair of the cortical plate.

The hopeless tooth: when is treatment futile?

The decision to place a tooth in the hopeless category is by no means a simple one. There is always the possibility of being wrong, the possibility that this tooth may prove to be the exception and, against all odds, survive as a functioning component of the masticatory apparatus. These are the decisions that make us dentists rather than technicians.

The beginning of the end of the antibiotic era? Part II. Proposed solutions to antibiotic abuse

The bacteria causing diseases that are now becoming serious public health threats are neither strange nor exotic, but rather shockingly familiar. Tuberculosis, typhoid fever, meningitis, pneumonia, and septicemias are emerging global threats. The infectious agents causing these serious threats are the same bacteria identified many decades ago. The only difference is that these and other microorganisms are no longer killed by the "miracle drugs" that have kept them at bay for the past six decades. Antibiotic resistance has made potential killers out of bacteria that previously posed little threat to mankind. The indiscriminate and reckless use of antibiotics has led to a fast-approaching crisis in which human dominance of the planet is threatened by single, elementary cells of the microbial world. Part I of this article detailed the causes of the crisis. Part II addresses the solutions that are recommended by national and international authorities and organizations.

The beginning of the end of the antibiotic era? Part I. The problem: abuse of the "miracle drugs"

The antibiotic era began in the early 1940s with the clinical use of penicillin. Subsequent discovery, development, and clinical use of other antibiotics resulted in effective therapy against major bacterial pathogens. These drugs were so effective that bacterial infectious diseases were considered by many experts to be under complete therapeutic control. However, the scientific community grossly underestimated the remarkable genetic plasticity of these organisms and their ability, through mutations and genetic transfer, to develop resistance to antibiotics. Infectious diseases are now the world's major cause of death. The cause of bacterial reemergence as a threat to human health and life is the abuse of the "miracle drugs." The ubiquitous nature of antibiotics in the human ecosystem foments bacterial resistance and threatens to eliminate antibiotics as effective drugs for human therapeutic use.

Excisional wound healing following the use of IRM as a root-end filling material

Intermediate Restorative Material (IRM) has been advocated as a root-end filling material based primarily on reports of clinical success and various leakage studies. The objectives of this study were to determine the excisional wound healing responses of the periradicular tissues to IRM root-end filling material and to compare this with the wound healing responses to amalgam and orthograde gutta-percha root-end filling materials. Mandibular premolars in dogs were obturated, root-ends resected, and the healing responses associated with root-end fillings of IRM, amalgam, and orthograde gutta-percha were evaluated microscopically and radiographically at postsurgical intervals of 10 and 45 days. The excisional wound healing responses associated with IRM root-end fillings were normal at both postsurgical intervals. There was no evidence of inhibition of dentoalveolar or osseous wound healing associated with IRM, amalgam, or orthograde gutta-percha. Statistical analysis showed no difference in wound healing between the 3 root-end filling materials.

Influence of three membrane types on healing of bone defects

OBJECTIVES

To determine and compare osseous regeneration associated with three guided tissue regeneration membrane types (expanded polytetrafluoroethylene, dense polytetrafluoroethylene, and an absorbable polylactic acid/citric acid ester base) and removal forces required for expanded and dense polytetrafluoroethylene membranes.

STUDY DESIGN

Bilateral osseous defects were created in 30 adult rat calvaria; one defect was covered with a test membrane and the other received no membrane (control). After 2 or 4 weeks, forces required for membrane removal from the tissues were electronically determined, and the calvaria removed and decalcified. Sections through the defects were stained and evaluated electronically and microscopically. Data were analyzed statistically.

RESULTS

Microscopic evaluation with Mann-Whitney U test revealed that dense polytetrafluoroethylene was associated with significantly greater bone formation than expanded polytetrafluoroethylene (p = 0.02) at 2 weeks and absorbable polylactic acid/citric acid ester base (p = 0.004) at 4 weeks. Electronic evaluation of the linear degree of fill with one way ANOVA and Tukey's test found no significant difference (p > 0.05) among the experimental or the control groups. In addition, the Mann-Whitney U test indicated that removal forces required for dense polytetrafluoroethylene were significantly less than for expanded polytetrafluoroethylene (p = 0.003).

CONCLUSIONS

The use of dense polytetrafluoroethylene as a membrane barrier deserves further investigation as it allows osseous regeneration, it is easier to remove from healing soft tissues, and it is inexpensive. A study with larger sample sizes should be conducted.

Intermediate cementum. Development, structure, composition, and potential functions

In the roots and root analogs of mammalian teeth a narrow zone of highly calcified tissue occupies the junction between cementum and dentin. This zone is referred to as "intermediate cementum," despite evidence that it is not a product of cementogenesis (or of dentinogenesis). Studies conducted on teeth of human and nonhuman primates indicate that the intermediate cementum layer contains enamel matrix proteins and is likely a product of Hertwig's epithelial root sheath. The available evidence regarding the development (origin), structure, and composition of intermediate cementum is reviewed, and the potential functions of this layer are assessed to include a possible role in wound healing.

Wound healing following demineralization of resected root ends in periradicular surgery

The objective of this study was to determine the effect of demineralization of resected root ends on the temporal and qualitative healing of the dentoalveolar (apical attachment apparatus) and alveolar (osseous) tissues in the excisional wound site created during periradicular surgery. Root end resections to orthograde gutta-percha obturations were performed on the mandibular premolars of six mongrel dogs. Twenty-four experimental root ends were demineralized by citric acid burnishing of the resected surfaces. The remaining 24 standard treatment root ends were not demineralized. Microscopic evaluations at postsurgical intervals from 4 to 45 days revealed that the demineralized root ends were associated with more rapid and complete healing than the nondemineralized root ends. It is proposed that demineralization enhances cementogenesis, the key to dentoalveolar healing, by removing the smear layer barrier and exposing the organic component (collagen fibrils) of resected cementum and dentin.

A comparison of leakage of filling materials in demineralized and non-demineralized resected root ends under vacuum and non-vacuum conditions

A study was conducted to compare the marginal apical leakage of root-end filling materials under vacuum and non-vacuum conditions, and to assess the effect of demineralization by application of citric acid to the root ends on the apical marginal leakage of root end filling materials. The root canals of 148 extracted human canines and premolars were handfiled and sealed with gutta-percha and Roth's 801 sealer using cold lateral condensation. The teeth were divided into 8 groups that received retrofilling materials. The materials tested were amalgam, IRM and gutta-percha/sealer with and without successive application of citric acid. Half of the specimens were placed under vacuum conditions in methylene blue dye, and the other half were placed in the dye for the same time period without exhausting air from the flask. The teeth were split longitudinally and the extent of dye penetration was determined with a stereomicroscope and eyepiece micrometer. The most evident difference in dye penetration was found between the positive control groups. Under vacuum conditions, the positive controls showed complete penetration of the unobturated canal system with dye. With passive immersion only partial penetration of the unobturated canal system occurred. Application of citric acid to the root end did not adversely affect the seal of amalgam, IRM or gutta-percha/sealer.

Dental implants to rehabilitate a patient with an unrepaired complete cleft of the hard and soft palate: a clinical report

Prosthetic rehabilitation of an edentulous adult with a complete residual cleft of his palates is presented. Lack of retention of his prosthesis made speech and eating difficult. Four osseointegrated dental implants were used to join the right and left maxillae and to provide mechanical retention for a complete overdenture obturator to improve function.

Surgical management of endodontically treated teeth

Surgical endodontics has become an important treatment modality in modern dentistry. The evolution and development of this modality has suffered from decades of empiricism, as techniques, concepts, and root-end filling materials were advocated without supporting scientific evidence. The techniques and concepts of periodontal surgery and oral and maxillofacial surgery were long assumed to directly apply to endodontic surgery. Evidence now suggests that certain procedures adopted from other specialties are not indicated for surgical endodontics and, in fact, may be counterproductive. During the past year, the most important developments have emerged in the area of surgical wound healing as it relates to soft tissue management procedures. New techniques and concepts that enhance rapid wound healing and decrease untoward postsurgical sequelae have been proposed.

Wound healing in the tissues of the periodontium following periradicular surgery. 2. The dissectional wound

Wound healing responses of the tissues of the periodontium following periradicular surgery in rhesus monkeys were evaluated by light microscopy. Part II of this investigation reports the responses of mucoperiosteal and osseous tissues to blunt dissectional wounding resulting from the reflection of triangular or submarginal rectangular flaps. Healing of the dissectional wound is rapid, although slower than the incisional wound. Granulation tissues replaces the fibrin clot in the wound site as early as 4 days after surgery, and is replaced by fibrous connective tissue by 14 days. Minimal differences were found in the temporal and qualitative dissectional wound-healing responses to the two types of flap designs. The periosteum does not survive the flap reflection procedure. The cells of the cambium layer are destroyed and the collagen of the fibrous layer undergoes depolymerization. It is postulated that the depolymerized periosteal collagen plays a role in rapid reattachment of flapped tissues to cortical bone.

Wound healing in the tissues of the periodontium following periradicular surgery. I. The incisional wound

Periradicular surgical procedures were performed on rhesus monkeys and the wound healing responses of the tissues of the periodontium were evaluated by light microscopy. This article, Part I of the investigation, reports the mucoperiosteal tissue wound healing responses to incisional wounds of the triangular and submarginal rectangular flap designs. Little difference was found in the temporal and qualitative healing responses to incisional wounds of the two flap designs. However, the submarginal rectangular design showed less predictable results, with a greater intersample variation of wound healing responses in the earlier postsurgical evaluation periods. Vital connective tissue and epithelium, although not visible clinically, remain attached to the root surfaces following reflection of flaps which include an intrasulcular incision. Preservation of these root-attached tissues prevented apical epithelial down-growth along the root surfaces and loss of soft tissue attachment levels. Vitality of root-attached tissues was preserved by preventing dehydration, avoiding curettement of root surfaces, and using a flap reflection technique which eliminates reflective forces in the intrasulcular incisional wound site.

Healing of surgical wounds in oral mucoperiosteal tissues

This report provides a review of the major biological events that occur in the oral mucoperiosteal tissues following simple surgical wounding. The chronological sequence and interrelationships of mucoperiosteal tissue wound healing responses are described. The objectives of this review are to provide clarification of wound healing terminology and a basic reference source for further investigative research into the wound healing responses to endodontic surgery.

Copper-zinc superoxide dismutase activity in normal and inflamed human dental pulp tissue

Information regarding the presence of the free radical scavenging (inactivating, dismutating) enzyme superoxide dismutase in human dental pulp was sought. Free radicals, such as the superoxide anion radical (O2-) and the hydroxyl anion radical (OH.), are powerful biological oxidants produced by phagocytes during the normal tissue response to injury and infection. Also produced is hydrogen peroxide (H2O2), an aggressive oxygen species formed by the reaction of superoxide with itself, i.e., a dismutation in which one molecule of O2- is oxidized by the other. These three reactive oxygen intermediates serve as part of the normal host biological defense mechanism for the inactivation of microorganisms and the breakdown of their toxic products. Both normal and inflamed dental pulps were assayed for the presence of this enzyme. Superoxide dismutase activity was identified in the normal pulpal tissues. There was a slight decrease in activity with age. In the inflamed pulpal tissues, enzyme activity was markedly and significantly increased in comparison to that in the normal tissues. These observations indicate that human dental pulp possesses an endogenous defense mechanism designed to protect the tissue components (cells and matrix) from the toxic effects of the reactive oxygen intermediates. In this regard, the inflammatory response of this specialized and somewhat isolated (compartmentalized) tissue is not unlike that seen in other connective tissues.

An ultrastructural and immunohistochemical study of human dental pulp: identification of Weibel-Palade bodies and von Willebrand factor in pulp endothelial cells

Special and specific immunohistochemical techniques as well as routine transmission electron microscopy were used to identify the presence of von Willebrand factor (vWF), a blood clotting factor essential to normal hemostasis, and Weibel-Palade bodies (WPB's), respectively, in the endothelial cells lining the blood vessels from both normal and inflamed human pulpal tissues. In human endothelial cells, WPB's are peculiar and specialized organelles which store vWF. All classes of blood vessels (capillaries, arterioles, arteries, venules, and veins) were vWF positive. The fine structural studies showed similar results with regard to the presence of WPB's. Interestingly, morphometric analyses conducted on the same tissues using either light or transmission electron microscopy showed that significantly more vWF-positive blood vessels were seen in the inflamed tissues. In agreement with the latter observation, transmission electron microscopy showed that more vascular endothelial cells contained WPB's in the inflamed tissues when compared with the normal tissues. From this it appears that during pulpal inflammation, the cascade of events associated with hemostasis may be activated with the increased synthesis and release of vWF by endothelial cells.

Comparison of the antimicrobial effectiveness of regular and fresh scent Clorox

The antimicrobial properties of two different compositions of sodium hypochlorite were compared in a tube dilution study. Absorbent paper points were contaminated with Streptococcus faecalis or Candida albicans and exposed to 5.25% or 2.62% concentrations of "regular" or "fresh scent" sodium hypochlorite (Clorox) for periods ranging from 15 to 120 s. The points were then removed from the sodium hypochlorite solution, placed into a growth medium, incubated, and the presence or absence of growth recorded. Results showed that formulary changes involved in the manufacture of the "fresh scent" sodium hypochlorite had no apparent effect on its antimicrobial properties, as both compositions proved equally effective against the test organisms at each concentration evaluated.

Hospital management of a patient with factitial dermatitis

A 64-year-old male with a 40-year history of dermatologic disorders is presented. The patient carries diagnoses of neurodermatitis and suspected myosis fungoides on which has been superimposed a factitial dermatitis requiring increasingly extended hospitalizations. Given a very disturbed home life and personality style, the patient showed no incentive for change, and his family and caregivers became increasingly frustrated and distraught. An operant behavioral approach proved helpful to staff in standardizing care and setting realistic expectations. This led to a reversal of a downward course and to a coordinated discharge.

Irrigation of the root canal system

Debridement of the root canal system is essential for predictably successful endodontic therapy. The use of an endodontic irrigant during canal preparation is necessary to adequately debride the canal system. A review of the scientific evidence related to the desirable properties of an endodontic irrigant indicates that a solution of 5.25 per cent sodium hypochlorite is currently the irrigant of choice. This chemical agent exhibits powerful antimicrobial activity, is an excellent necrotic tissue solvent, and is the most efficient irrigant in removing organic debris from the root canal system.

The effect of root resection on the sealing property of root canal obturations

Root canal systems of extracted anterior teeth were obturated with sealer and either multiple gutta-percha cones or single silver cones. The effect of root resection on the sealing property of these obturating materials was evaluated by autoradiographic methods. Results indicate that root resection with a rotary instrument in a high-speed handpiece does not adversely affect the sealing property of well-condensed gutta-percha-sealer obturations.

An analysis of the sensitivity of non-rereduced PRS medium in endodontic therapy

A total of 244 paired samples were obtained from sixty-one root canal systems at four specific stages of endodontic treatment. Half the samples were placed in a commonly used endodontic medium and incubated aerobically. The remaining samples were placed in PRS medium and incubated in an anaerobic environment. The rereduction procedure, used to remove oxygen entering the PRS medium at the time of insertion of the sample, was not employed. A statistical analysis of the results indicates that the non-rereduced PRS medium is not as sensitive as rereduced PRS and offers no significant advantages over trypticase soy broth with 0.1 percent agar.

A statistical analysis of anaerobic versus aerobic culturing in endodontic therapy

Asymptomatic teeth were cultured at four specific stages of endodontic therapy, yielding 148 paired samples. Half of the samples were incubated anaerobically with the use of a new medium, and half were incubated aerobically with the use of a commonly employed endodontic medium. The former proved to be significantly more sensitive in supporting microbial growth from root canals. The results indicate that an aerobic culturing technique alone is not sufficient to reflect the microbiologic status of the canal system.

The epithelized oral sinus tract

Sinus tracts that extended from periapical lesions to the alveolar mucosa were surgically removed and examined microscopically. The results indicate that sinus tracts may be lined with stratified squamous epithelium. More commonly, however, these tracts are lined with granulation tissue.

Osteosarcoma associated with metallic implants. Report of two cases in dogs

This is a report of two dogs in which osteosarcomas arose in association with metallic orthopedic implants. One neoplasm occurred in the distal humerus of a 12-year-old Doberman Pinscher. A stainless steel intramedullary pin had been implanted in the bone 11 years previously. Upon removal, corrosion of the pin was noted. The second neoplasm arose in the proximal tibia of a 12-year-old Irish Wolfhound. Six years previously, a fracture of the tibia had been repaired with a plate and screws made of the same type stainless steel, type 316L, by the same manufacturer. No corrosion appeared to have occured. Infection had not occured in either animal.

The effect of neutralizing agents on aqueous parachlorophenol

The effect of possible neutralizing agents on aqueous parachlorophenol were studied. Results indicated that saline, EDTAC, dentin, saliva, prolonged light exposure, and thermal extremes do not appreciably affect the antibacterial properties of aqueous parachlorophenol. The presence of blood and necrotic tissue demonstrated a marked inhibitory effect.