Ultrastructural aspects of two different mast cell populations in human healthy gingival tissue

The results of our recent microscopy studies clearly have demonstrated the constant presence of numerous metachromatic cells in healthy human gingival connective tissue. Despite the great number of studies on mast cell population in many human organs (lung, skin, uterus, and bowel), at the present time few are the studies regarding the morphostructural aspects of mast cells in the human gingiva. The aim of this study was to assess by transmission electron microscopy the presence of mast cells in the healthy human gingiva and to characterize the ultrastructural aspects of mast cells populations. 30 specimens of human gingival tissue were collected from 30 patients with informed consent. The samples were prepared for T.E.M. examination. In all the ultrathin sections observed we detected numerous and ubiquitarious mast cells. These exhibited several morphological types of cytoplasmic granules with characteristic subgranular architectural variety in shape and density. This allowed us to divide mast cells into two groups: cells with granules consisted of compact coiled scrolls, fine granular material and lattice - grating configuration, and cells containing granules with discrete scrolls formed by more concentric lamellae and particulate structure. The two ultrastructural aspects observed correspond to McTC and McT of the international literature. Therefore in the human gingival connective tissue, like in other organs, two types of mast cells are clearly present. Surprisingly, the human gingival tissue shows, like the lung, McT as the prevailing subpopulation, in contrast to the skin, uterus and gastrointestinal submucosa where McTC prevail. Dans le cadre d’une étude sur la population cellulaire du tissu conjonctif gingival humain nous avons constaté, en microscopie optique, la présence constante de nombreuses cellules metachromatiques. Pour définir la nature de telles cellules et pour en déterminer les aspects ultra-structuraux, nous avons étudié au microscope électronique à transmission 30 biopsies du tissu gingival humain, cliniquement sain. Dans tous les échantillons examinés nous avons observé de nombreux mastocytes dont le contenu granulaire nous est apparu caractérisé par un aspect « à particules » et « en rouleaux » ou bien, dans d’autres éléments cellulaires, par un aspect «en grillage». Les deux aspects ultrastructuraux décrits nous permettent de distinguer les mastocytes gingivaux en deux sous-populations, différentes comme l’ont confirmé plusieurs auteurs, selon la localisation anatomique, selon la structure intérieure et le contenu enzymatique des granules, et, enfin, selon la réaction à des substances sécrétagogues

Fissure ridges: A reappraisal of faulting and travertine deposition (travitonics)

The mechanical discontinuities in the upper crust (i.e., faults and related fractures) lead to the uprising of geothermal fluids to the Earth’s surface. If fluids are enriched in Ca2+ and HCO3‐, masses of CaCO3 (i.e., travertine deposits) can form mainly due to the CO2 leakage from the thermal waters. Among other things, fissure‐ridge‐type deposits are peculiar travertine bodies made of bedded carbonate that gently to steeply dip away from the apical part where a central fissure is located, corresponding to the fracture trace intersecting the substratum; these morpho‐tectonic features are the most useful deposits for tectonic and paleoseismological investigation, as their development is contemporaneous with the activity of faults leading to the enhancement of permeability that serves to guarantee the circulation of fluids and their emergence. Therefore, the fissure ridge architecture sheds light on the interplay among fault activity, travertine deposition, and ridge evolution, providing key geo‐chronologic constraints due to the fact that travertine can be dated by different radio-metric methods. In recent years, studies dealing with travertine fissure ridges have been consider-ably improved to provide a large amount of information. In this paper, we report the state of the art of knowledge on this topic refining the literature data as well as adding original data, mainly focusing on the fissure ridge morphology, internal architecture, depositional facies, growth mechanisms, tectonic setting in which the fissure ridges develop, and advantages of using the fissure ridges for neotectonic and seismotectonic studies

Considérations sur des tests de biocompatibilité «in vivo» et «in vitro» de quelques ciments endodontiques

The major goal endodontic therapy has been achieved by condensing filling materials into the root canal. It’s not uncommon to find excess material into the periapical tissue. It therefore becomes obligatory to use fillings materials that have acceptable biocompatibility.The purpose of this investigation was to obtain a «toxicity profile» of some endodontics materials and to compare our observations to results present in literature.The gutta-percha and five endodontic filling cements were tested «in vivo» and «in vitro».The in vivo biocompatibility involved the placement of the test material in 10 mm. Teflon tubes with an outer diameter of 1.3 mm which were implanted subcutaneously into rats. The implants were left in situ for periods of 30 and 90 days. The «hemolysis test» is designed for «in vitro» evaluations.The istological examination showed different intensity and extent cellular responses. In some cases severe infiltration of inflammatory cell and areas with necrotis were seen.At conclusion, the endodontics material evaluated showed slight, moderate and severe reactions; therefore a different pattern in tissue response.Dans le domaine odontologique, ainsi que dans les autres branches de la médecine, l’exigence d’améliorer constamment la biocompatibilité des matériaux utilisés comme thérapeutique, surtout quand ces matériaux sont destinés à «cohabiter» longtemps avec l’organisme, est de plus en plus ressentie.Dans le cadre d’un vaste programme de recherche, les auteurs se sont proposé d’évaluer la biocompatibilité réelle de quelques matériaux endodontiques choisis parmi les plus courants en Italie: c’est dans ce but qu’ont été effectués des tests «in vitro» (test de l’émolyse d’hématies de lapin) et «in vivo» (selon la technique de Safavi et al. qui prévoit l’implantation du matériel à tester dans le tissu sous-cutané du rat).Les résultats des tests ont démontré la variabilité du grade de biocompatibilité des matériaux soumis à l’expérimentation. Certains matériaux n’ont provoqué en effet qu’une légère réaction des tissus, d’autres ont déterminé la formation d’importants infiltrats de cellules inflammatoires, de macrophages, de cellules géantes de corps étranger et de colliquation nécrotique tissulaire

Les perles d’émail: aspects ultrastructuraux et hypothèses de morphogenèse

Five enamel pearls were examined by Scanning Electron Microscope. Some external pearls presented a bare enamel surface, others were covered by a thin layer of cementum.The enamel pearls showed irregular dystrofic enamel surface or a thin layer without structure, rows of irregular Tome’s processes pits, enamel caps and focal holes. Some enamel pearls revealed little areas of enamel surface resorption like-resorbing lacunae with, in some cases, areas of tissue repair.La perle d’émail est une masse circulaire de matériel calcifié qui apparait le plus souvent dans la bifurcation des molaires et est attachée à la surface externe de la dent. Elle peut aussi être interne mais nous en savons très peu à ce sujet à cause du manque de publications. Cinq perles externes ont été observées au microscope électronique à balayage.Tandis que certaines perles externes présentent une surface à nu, d’autres sont recouvertes d’une fine couche de cément qui les protège. La surface de la perle d’émail présente des zones irrégulières d’hypominéralisation ou une fine couche sans structure, des rangées de petits trous irréguliers des processus de Tome et des trous focaux et des cratères

Ethical Issues in the Use of Suboptimal Kidneys for Transplants: an Italian Point of View

The shortage of organs leads to the need for utilizing suboptimal kidneys for transplantation. The distinction between optimal, marginal, and suboptimal kidneys leads surgeons to face not only technical problems but also ethical and legal issues related to clinical advantages offered by the transplant of a nonstandard kidney and the acquisition of consent. Between 1999 and 2015, we performed 658 transplants, 49 (7.5%) using suboptimal kidneys. All patients were alive and with vital graft throughout follow-up. We did not encounter any major surgical complications. From a technical point of view, our experience and literature review confirm that transplant of suboptimal kidney leads to good clinical results but exposes patients to a increased risks of surgical complications. Therefore, these interventions must take place in hospitals fully prepared for this type of surgery and performed by experienced transplant surgeons with proper matching between organ and recipient. Considering the insufficient resources available, from an ethical and legal point of view, doctors play an essential role in optimizing the use of these kidneys by avoiding wastage of organs, ensuring that transplants are done in suitable patients, and that patients are fully informed and aware of the risks and benefits associated with the specific suboptimal kidney being transplanted. We believe that, in highly specialized centers, the number of suboptimal kidney transplants should be increased, as their use has shown good clinical results and carries fewer ethical issues compared with marginal kidneys. Further, suboptimal kidneys may also be proposed for use in young patients with end-stage renal disease

Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic

Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

Intraperitoneal drain placement and outcomes after elective colorectal surgery: international matched, prospective, cohort study

Despite current guidelines, intraperitoneal drain placement after elective colorectal surgery remains widespread. Drains were not associated with earlier detection of intraperitoneal collections, but were associated with prolonged hospital stay and increased risk of surgical-site infections.Background Many surgeons routinely place intraperitoneal drains after elective colorectal surgery. However, enhanced recovery after surgery guidelines recommend against their routine use owing to a lack of clear clinical benefit. This study aimed to describe international variation in intraperitoneal drain placement and the safety of this practice. Methods COMPASS (COMPlicAted intra-abdominal collectionS after colorectal Surgery) was a prospective, international, cohort study which enrolled consecutive adults undergoing elective colorectal surgery (February to March 2020). The primary outcome was the rate of intraperitoneal drain placement. Secondary outcomes included: rate and time to diagnosis of postoperative intraperitoneal collections; rate of surgical site infections (SSIs); time to discharge; and 30-day major postoperative complications (Clavien-Dindo grade at least III). After propensity score matching, multivariable logistic regression and Cox proportional hazards regression were used to estimate the independent association of the secondary outcomes with drain placement. Results Overall, 1805 patients from 22 countries were included (798 women, 44.2 per cent; median age 67.0 years). The drain insertion rate was 51.9 per cent (937 patients). After matching, drains were not associated with reduced rates (odds ratio (OR) 1.33, 95 per cent c.i. 0.79 to 2.23; P = 0.287) or earlier detection (hazard ratio (HR) 0.87, 0.33 to 2.31; P = 0.780) of collections. Although not associated with worse major postoperative complications (OR 1.09, 0.68 to 1.75; P = 0.709), drains were associated with delayed hospital discharge (HR 0.58, 0.52 to 0.66; P < 0.001) and an increased risk of SSIs (OR 2.47, 1.50 to 4.05; P < 0.001). Conclusion Intraperitoneal drain placement after elective colorectal surgery is not associated with earlier detection of postoperative collections, but prolongs hospital stay and increases SSI risk