Swiss paediatric dentists' preferences and experience on the use of articaine and other local/topical anaesthetics

PURPOSE

This study was conducted to explore the preference and experience of paediatric dentists based in Switzerland regarding the use of articaine and other local and topical anaesthesia.

METHODS

An 18-question survey was developed, piloted, and distributed to the members of the Swiss association of paediatric dentistry (n = 460). The following information were collected: most used local anaesthetic in different age groups, time needed to inject a full ampule, frequency of observed local and systemic side effects, application of topical anaesthetic prior to injection, time waited between application and the injection, and perceived effectiveness of topical anaesthetic. The dentists' responses were analysed with logistic regressions reporting odds ratios (OR) and 95% confidence intervals (CI) at 5%.

RESULTS

The response rate was 37% (n = 168) out of the 460 questionnaires sent, with the responders being predominantly female (67%) and 47-year-old on average. More than 80% of the dentists used articaine in all age groups. 45% of responders took longer than 60 s to inject a full ampule. Local and systemic side-effects were observed by 82% and 28% of respondents respectively, although the nature and the significance of those were not detailed due to the anonymous nature of the questionnaire. Significantly less local adverse effects were seen for older children (p = 0.04) and among dentists with more years of experience (p = 0.01). Most responders applied topical anaesthetic and half of them waited longer than 60 s before injection.

CONCLUSIONS

Articaine is a widely used local anaesthetic by the studied group of Swiss paediatric dentists regardless of patient's age. The use of topical anaesthetic before injection is a common practice with good perceived effectiveness.

In vitro evaluation of fissure sealants' wear under erosive, abrasive and erosive/abrasive conditions

PURPOSE

To evaluate and compare the wear of selected resin-based fissure sealants with different compositions properties under erosive, abrasive, and erosive/abrasive conditions.

METHODS

Forty-five samples of the following resin-based fissure sealants were prepared: Fissurit (fluoride free), Fissurit F (with fluoride), Fissurit FX (55 wt.% filler content), Grandio Seal (70 wt.% nano-filler content) and bovine enamel. Fifteen samples from each material were randomly allocated into three groups according to the wear condition they would be subjected to as follows: erosive condition (citric acid, 1 min, pH 2.3), abrasive condition (120 brushing strokes at 2 N, toothpaste slurry RDA value = 69), and erosive/abrasive condition (combination of both). The wear challenges were repeated six times each day for 10 days. The material wear was measured using a stylus profilometer. Kruskal-Wallis and Conover's test was applied to compare the resulting material wear between the groups.

RESULTS

Under erosive conditions, Grandio Seal and Fissurit FX showed statistically significantly the least material wear. Under abrasive and erosive/abrasive conditions, Grandio Seal showed statistically significantly the least material wear. Fissurit F showed statistically significantly the highest material wear under abrasive and erosive/abrasive conditions, after dental enamel (p < 0.05).

CONCLUSION

Higher filler content in sealants leads to better wear resistance. Incorporating fluoride into sealants seems to reduce their wear resistance at similar filler contents.

Abstract 555: Allogeneic Natural Killer cells engineered to express HER2 CAR, Interleukin 15 and TGF beta dominant negative receptor effectively control HER2+ tumors

Despite the success of HER2 targeted therapies in HER2+ breast and gastric cancer, additional therapies are needed to address treatment-resistant metastatic disease. Adoptive immune cell therapy is a promising therapeutic modality given the remarkable clinical responses seen with autologous chimeric antigen receptor (CAR) T cells in hematological malignancies. However, success of cell therapy in solid tumors has been more limited. Three major impediments to the success of adoptive cell therapies in solid tumors are the heterogeneity of antigen expression, the immunosuppressive tumor microenvironment (TME), and the inherent challenges of manufacturing autologous cells and consequent variability of these cell products. Engineered, off-the-shelf, allogeneic Natural Killer (NK) cells provide a solution to these challenges. We describe here CAT-179, a novel engineered CAR-NK cell therapeutic for HER2+ solid tumors. CAT-179 cells express three transgenes: a HER2-directed CAR to effectively eliminate tumor cells, a Transforming Growth Factor (TGF) β dominant negative receptor (DNR) for resistance to TGFβ -mediated immunosuppression in the TME, and Interleukin 15 (IL15) cytokine to enhance NK cell persistence and activity for durable response. High efficiency engineering of the large (~3.7Kb) cargo containing CAR, IL15, and DNR in CAT-179 is enabled by the non-viral TC Buster™ Transposon System. Transposon engineering of CAT-179 results in high and stable expression of CAR (45% CAR at day 7 post gene delivery) without the need for post-engineering selection. CAT-179 demonstrates both CAR-dependent and innate NK receptor-dependent tumor cell killing in vitro, reducing the likelihood of tumor escape through antigen loss. CAT-179 effectively kills in vitro both high HER2-expressing SKOV3 cells as well as lower HER2-expressing HT-29 cells. CAT-179 also demonstrates resistance to TGFβ mediated immunosuppression, as evidenced by 75% reduction in TGFβ -induced phosphorylation of SMAD2 as well as prevention of TGFβ induced downregulation of NK cell activating receptors and restoration of NK cell cytotoxic activity. These data suggest CAT-179 cells will be protected from TGFβ -mediated immune suppression in the TME. Finally, the addition of IL15 in CAT-179 significantly enhances persistence for at least fourteen days in vitro without the need for exogenous cytokines. Moreover, CAT-179 administration to NSG mice showed expansion and persistence of the transferred cell product. CAT-179 addresses key hurdles to allogeneic cell therapy for solid tumors and is a promising new therapeutic approach for HER2 expressing breast, gastric and other tumors.

Citation Format: Celeste Richardson, Finola Moore, Andres Alvarez, Alexia Barandiaran, Luke Barron, Eugene Choi, Tucker Ezell, Charlotte Franco, Bashar Hamza, Jennifer Johnson, Annie Khamhoung, Taeyoon Kyung, Marilyn Marques, Dominic Picarella, Jared Sewell, Alex Storer, Meghan Walsh, Vipin Suri. Allogeneic Natural Killer cells engineered to express HER2 CAR, Interleukin 15 and TGF beta dominant negative receptor effectively control HER2+ tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 555.

Measuring kinetics and metastatic propensity of CTCs by blood exchange between mice

Existing preclinical methods for acquiring dissemination kinetics of rare circulating tumor cells (CTCs) en route to forming metastases have not been capable of providing a direct measure of CTC intravasation rate and subsequent half-life in the circulation. Here, we demonstrate an approach for measuring endogenous CTC kinetics by continuously exchanging CTC-containing blood over several hours between un-anesthetized, tumor-bearing mice and healthy, tumor-free counterparts. By tracking CTC transfer rates, we extrapolated half-life times in the circulation of between 40 and 260 s and intravasation rates between 60 and 107,000 CTCs/hour in mouse models of small-cell lung cancer (SCLC), pancreatic ductal adenocarcinoma (PDAC), and non-small cell lung cancer (NSCLC). Additionally, direct transfer of only 1-2% of daily-shed CTCs using our blood-exchange technique from late-stage, SCLC-bearing mice generated macrometastases in healthy recipient mice. We envision that our technique will help further elucidate the role of CTCs and the rate-limiting steps in metastasis.

YAP Enhances Tumor Cell Dissemination by Promoting Intravascular Motility and Reentry into Systemic Circulation

The oncogene YAP has been shown previously to promote tumor growth and metastasis. However, how YAP influences the behavior of tumor cells traveling within the circulatory system has not been as well explored. Given that rate-limiting steps of metastasis are known to occur while tumor cells enter, travel through, or exit circulation, we sought to study how YAP influences tumor cell behavior within the circulatory system. Intravital imaging in live zebrafish embryos revealed that YAP influenced the distribution of tumor cells within the animal following intravenous injection. Control cells became lodged in the first capillary bed encountered in the tail, whereas cells overexpressing constitutively active YAP were able to travel through this capillary plexus, reenter systemic circulation, and seed in the brain. YAP controlled transit through these capillaries by promoting active migration within the vasculature. These results were corroborated in a mouse model following intravenous injection, where active YAP increased the number of circulating tumor cells over time. Our results suggest a possible mechanism whereby tumor cells can spread to organs beyond the first capillary bed downstream from the primary tumor. These results also show that a specific gene can affect the distribution of tumor cells within an animal, thereby influencing the global pattern of metastasis in that animal. SIGNIFICANCE: These findings demonstrate that YAP endows tumor cells with the ability to move through capillaries, allowing them to return to and persist in circulation, thereby increasing their metastatic spread.See related commentary by Davidson, p. 3797.

A Worldwide Competition to Compare the Speed and Chemotactic Accuracy of Neutrophil-Like Cells

Chemotaxis is the ability to migrate towards the source of chemical gradients. It underlies the ability of neutrophils and other immune cells to hone in on their targets and defend against invading pathogens. Given the importance of neutrophil migration to health and disease, it is crucial to understand the basic mechanisms controlling chemotaxis so that strategies can be developed to modulate cell migration in clinical settings. Because of the complexity of human genetics, Dictyostelium and HL60 cells have long served as models system for studying chemotaxis. Since many of our current insights into chemotaxis have been gained from these two model systems, we decided to compare them side by side in a set of winner-take-all races, the Dicty World Races. These worldwide competitions challenge researchers to genetically engineer and pharmacologically enhance the model systems to compete in microfluidic racecourses. These races bring together technological innovations in genetic engineering and precision measurement of cell motility. Fourteen teams participated in the inaugural Dicty World Race 2014 and contributed cell lines, which they tuned for enhanced speed and chemotactic accuracy. The race enabled large-scale analyses of chemotaxis in complex environments and revealed an intriguing balance of speed and accuracy of the model cell lines. The successes of the first race validated the concept of using fun-spirited competition to gain insights into the complex mechanisms controlling chemotaxis, while the challenges of the first race will guide further technological development and planning of future events.

Microfluidic assay for precise measurements of mouse, rat, and human neutrophil chemotaxis in whole-blood droplets

Animal models of human disease differ in innate immune responses to stress, pathogens, or injury. Precise neutrophil phenotype measurements could facilitate interspecies comparisons. However, such phenotype comparisons could not be performed accurately with the use of current assays, as they require the separation of neutrophils from blood using species-specific protocols, and they introduce distinct artifacts. Here, we report a microfluidic technology that enables robust characterization of neutrophil migratory phenotypes in a manner independent of the donor species and performed directly in a droplet of whole blood. The assay relies on the particular ability of neutrophils to deform actively during chemotaxis through microscale channels that block the advance of other blood cells. Neutrophil migration is measured directly in blood, in the presence of other blood cells and serum factors. Our measurements reveal important differences among migration counts, velocity, and directionality among neutrophils from 2 common mouse strains, rats, and humans.

Whole blood human neutrophil trafficking in a microfluidic model of infection and inflammation

Appropriate inflammatory responses to wounds and infections require adequate numbers of neutrophils arriving at injury sites. Both insufficient and excessive neutrophil recruitment can be detrimental, favouring systemic spread of microbes or triggering severe tissue damage. Despite its importance in health and disease, the trafficking of neutrophils through tissues remains difficult to control and the mechanisms regulating it are insufficiently understood. These mechanisms are also complex and difficult to isolate using traditional in vivo models. Here we designed a microfluidic model of tissue infection/inflammation, in which human neutrophils emerge from a droplet-size samples of whole blood and display bi-directional traffic between this and micro-chambers containing chemoattractant and microbe-like particles. Two geometrical barriers restrict the entrance of red blood cells from the blood to the micro-chambers and simulate the mechanical function of the endothelial barrier separating the cells in blood from cells in tissues. We found that in the presence of chemoattractant, the number of neutrophils departing the chambers by retrotaxis is in dynamic equilibrium with the neutrophils recruited by chemotaxis. We also found that in the presence of microbe-like particles, the number of neutrophils trapped in the chambers is proportional to the number of particles. Together, the dynamic equilibrium between migration, reversed-migration and trapping processes determine the optimal number of neutrophils at a site. These neutrophils are continuously refreshed and responsive to the number of microbes. Further studies using this infection-inflammation-on-a-chip-model could help study the processes of inflammation resolution. The new in vitro experimental tools may also eventually help testing new therapeutic strategies to limit neutrophil accumulation in tissues during chronic inflammation, without increasing the risk for infections.

A microfluidic device for label-free, physical capture of circulating tumor cell clusters

Cancer cells metastasize through the bloodstream either as single migratory circulating tumor cells (CTCs) or as multicellular groupings (CTC-clusters). Existing technologies for CTC enrichment are designed primarily to isolate single CTCs, and while CTC-clusters are detectable in some cases, their true prevalence and significance remain to be determined. Here, we developed a microchip technology (Cluster-Chip) specifically designed to capture CTC-clusters independent of tumor-specific markers from unprocessed blood. CTC-clusters are isolated through specialized bifurcating traps under low shear-stress conditions that preserve their integrity and even two-cell clusters are captured efficiently. Using the Cluster-Chip, we identify CTC-clusters in 30–40% of patients with metastatic cancers of the breast, prostate and melanoma. RNA sequencing of CTC-clusters confirms their tumor origin and identifies leukocytes within the clusters as tissue-derived macrophages. Together, the development of a device for efficient capture of CTC-clusters will enable detailed characterization of their biological properties and role in cancer metastasis.

Retrotaxis of human neutrophils during mechanical confinement inside microfluidic channels

The current paradigm of unidirectional migration of neutrophils from circulation to sites of injury in tissues has been recently challenged by observations in zebrafish showing that neutrophils can return from tissues back into the circulation. However, the relevance of these observations to human neutrophils remains unclear, the forward and reverse migration of neutrophils is difficult to quantify, and the precise conditions modulating the reverse migration cannot be isolated. Here, we designed a microfluidic platform inside which we observed human neutrophil migration in response to chemoattractant sources inside channels, simulating the biochemical and mechanical confinement conditions at sites of injury in tissues. We observed that, after initially following the direction of chemoattractant gradients, more than 90% of human neutrophils can reverse their direction and migrate persistently and for distances longer than one thousand micrometers away from chemoattractant sources (retrotaxis). Retrotaxis is enhanced in the presence of lipoxin A4 (LXA4), a well-established mediator of inflammation resolution, or Tempol, a standard antioxidant. Retrotaxis stops after neutrophils encounter targets which they phagocytise or on surfaces presenting high concentrations of fibronectin. Our microfluidic model suggests a new paradigm for neutrophil accumulation at sites of inflammation, which depends on the balance of three simultaneous processes: chemotaxis along diffusion gradients, retrotaxis following mechanical guides, and stopping triggered by phagocytosis.

A zebrafish compound screen reveals modulation of neutrophil reverse migration as an anti-inflammatory mechanism

Diseases of failed inflammation resolution are common and largely incurable. Therapeutic induction of inflammation resolution is an attractive strategy to bring about healing without increasing susceptibility to infection. However, therapeutic targeting of inflammation resolution has been hampered by a lack of understanding of the underlying molecular controls. To address this drug development challenge, we developed an in vivo screen for proresolution therapeutics in a transgenic zebrafish model. Inflammation induced by sterile tissue injury was assessed for accelerated resolution in the presence of a library of known compounds. Of the molecules with proresolution activity, tanshinone IIA, derived from a Chinese medicinal herb, potently induced inflammation resolution in vivo both by induction of neutrophil apoptosis and by promoting reverse migration of neutrophils. Tanshinone IIA blocked proinflammatory signals in vivo, and its effects are conserved in human neutrophils, supporting a potential role in treating human inflammation and providing compelling evidence of the translational potential of this screening strategy.

Microfluidic platform for measuring neutrophil chemotaxis from unprocessed whole blood

Neutrophils play an essential role in protection against infections and their numbers in the blood are frequently measured in the clinic. Higher neutrophil counts in the blood are usually an indicator of ongoing infections, while low neutrophil counts are a warning sign for higher risks for infections. To accomplish their functions, neutrophils also have to be able to move effectively from the blood where they spend most of their life, into tissues, where infections occur. Consequently, any defects in the ability of neutrophils to migrate can increase the risks for infections, even when neutrophils are present in appropriate numbers in the blood. However, measuring neutrophil migration ability in the clinic is a challenging task, which is time consuming, requires large volume of blood, and expert knowledge. To address these limitations, we designed a robust microfluidic assays for neutrophil migration, which requires a single droplet of unprocessed blood, circumvents the need for neutrophil separation, and is easy to quantify on a simple microscope. In this assay, neutrophils migrate directly from the blood droplet, through small channels, towards the source of chemoattractant. To prevent the granular flow of red blood cells through the same channels, we implemented mechanical filters with right angle turns that selectively block the advance of red blood cells. We validated the assay by comparing neutrophil migration from blood droplets collected from finger prick and venous blood. We also compared these whole blood (WB) sources with neutrophil migration from samples of purified neutrophils and found consistent speed and directionality between the three sources. This microfluidic platform will enable the study of human neutrophil migration in the clinic and the research setting to help advance our understanding of neutrophil functions in health and disease.

On-demand, competing gradient arrays for neutrophil chemotaxis

Neutrophils are the most abundant type of white blood cells in the circulation, protecting the body against pathogens and responding early to inflammation. Although we understand how neutrophils respond to individual stimuli, we know less about how they prioritize between competing signals or respond to combinational signals. This situation is due in part to the lack of adequate experimental systems to provide signals in controlled spatial and temporal fashion. To address these limitations, we designed a platform for generating on-demand, competing chemical gradients and for monitoring neutrophil migration. On this platform, we implemented forty-eight assays generating independent gradients and employed synchronized valves to control the timing of these gradients. We observed faster activation of neutrophils in response to fMLP than to LTB4 and unveiled for the first time a potentiating effect for fMLP during migration towards LTB4. Our observations, enabled by the new tools, challenge the current paradigm of inhibitory competition between distinct chemoattractant gradients and suggest that human neutrophils are capable of complex integration of chemical signals in their environment.

Three-Dimensional Holographic Refractive-Index Measurement of Continuously Flowing Cells in a Microfluidic Channel

Refractive index of biological specimens is a source of intrinsic contrast that can be explored without any concerns of photobleaching or harmful effects caused by extra contrast agents. In addition, RI contains rich information related to the metabolism of cells at the cellular and subcellular levels. Here, we report a no-moving parts approach that provides three-dimensional refractive index maps of biological samples continuously flowing in a microfluidic channel. Specifically, we use line illumination and off-axis digital holography to record the angular spectra of light scattered from flowing samples at high speed. Applying the scalar diffraction theory, we obtain accurate RI maps of the samples from the measured spectra. Using this method, we demonstrate label-free 3-D imaging of live RKO human colon cancer cells and RPMI8226 multiple myeloma cells, and obtain the volume, dry mass and density of these cells from the measured 3-D refractive index maps. Our results show that the reported method, alone or in combination with the existing flow cytometry techniques, promises as a quantitative tool for stain-free characterization of large number of cells.

Migration of neutrophils targeting amyloid plaques in Alzheimer's disease mouse model

Immune responses in the brain are thought to play a role in disorders of the central nervous system, but an understanding of the process underlying how immune cells get into the brain and their fate there remains unclear. In this study, we used a 2-photon microscopy to reveal that neutrophils infiltrate brain and migrate toward amyloid plaques in a mouse model of Alzheimer's disease. These findings suggest a new molecular process underlying the pathophysiology of Alzheimer's disease.

Malaria-infected erythrocyte-derived microvesicles mediate cellular communication within the parasite population and with the host immune system

Humans and mice infected with different Plasmodium strains are known to produce microvesicles derived from the infected red blood cells (RBCs), denoted RMVs. Studies in mice have shown that RMVs are elevated during infection and have proinflammatory activity. Here we present a detailed characterization of RMV composition and function in the human malaria parasite Plasmodium falciparum. Proteomics profiling revealed the enrichment of multiple host and parasite proteins, in particular of parasite antigens associated with host cell membranes and proteins involved in parasite invasion into RBCs. RMVs are quantitatively released during the asexual parasite cycle prior to parasite egress. RMVs demonstrate potent immunomodulatory properties on human primary macrophages and neutrophils. Additionally, RMVs are internalized by infected red blood cells and stimulate production of transmission stage parasites in a dose-dependent manner. Thus, RMVs mediate cellular communication within the parasite population and with the host innate immune system.

Measuring neutrophil speed and directionality during chemotaxis, directly from a droplet of whole blood

Neutrophil chemotaxis is critical for defense against infections and its alterations could lead to chronic inflammation and tissue injury. The central role that transient alterations of neutrophil chemotaxis could have on patient outcomes calls for its quantification in the clinic. However, current methods for measuring neutrophil chemotaxis require large volumes of blood and are time consuming. To address the need for rapid and robust assays, we designed a microfluidic device that measures neutrophil chemotaxis directly from a single droplet of blood. We validated the assay by comparing neutrophil chemotaxis from finger prick, venous blood and purified neutrophil samples. We found consistent average velocity of (19 ± 6 μm/min) and directionality (91.1%) between the three sources. We quantified the variability in neutrophil chemotaxis between healthy donors and found no significant changes over time. We also validated the device in the clinic and documented temporary chemotaxis deficiencies after burn injuries.

[Bilateral testicular hypertrophy and congenital adrenal hyperplasia caused by 11-beta-hydroxylase deficiency]

This study reports the case of a 5 1/2 year-old boy with congenital adrenal hyperplasia (11-beta-hydroxylase deficiency) and bilateral testicular hypertrophy. Microscopic and ultrastructural examinations did not show any nodular tumor or crystalloids or Reinke. However, interstitial cell hyperplasia was present which may have resulted in testicular enlargement. The patient had a younger brother also presenting with 11-beta-hydroxylase deficiency but with bilateral cryptorchidism. This suggests that ACTH hypersecretion alone is unlikely to be responsible for testicular enlargement.

Seroimmunity following vaccination in infants by an inactivated poliovirus vaccine prepared on Vero cells

An inactivated poliovirus vaccine prepared from cultures of Vero cells has been tested on 61 infants from two to 11 months of age (mean age, 4.3 months) for tolerance and serologic potency. Three doses of vaccine were given one month apart at the same time that diphtheria-tetanus-pertussis vaccine was injected at another body site. Poliovirus-neutralizing antibody titers were measured before the first and third injections and one month after each. The titer was considered positive when the dilution was greater than or equal to 1:4. The tolerance has been good. Thirty-one infants were assessable for serologic efficacy; all had significant serologic responses after two injections of polio vaccine, regardless of the titer of maternally transmitted antibodies before the immunizations. The third injection did not significantly increase the antibody titer observed after the first two doses.

[Fetal macrosomia and the study of risk factors in maternal diabetes]

The authors report the results of a study performed in 142 women who gave birth to overgrown neonates. Among them, the incidence of diabetes was high: 7.75%. Older maternal age, maternal obesity and the former birth of large infants were also found to be risk factors for fetal overgrowth.

Milk and lactation: some social and developmental correlates among 1,000 infants

Breast-feeding and artificial feeding practices in a developing country were examined and related to some social and developmental factors. This was done during the course of a transverse-type growth study of 1,000 infants from birth to 26 months of age. Three types of feeding were identified: breast, mixed, and artificial. The families were divided into three social categories. To give time for the effects of the type of feeding, groups of children at 6, 8, 10, 12, 14, and 16 months of age were studied. In view of the lack of data on feeding effects upon large samples, the study was performed to assess the relative effects of feeding on early childhood development (Bayley Motor and Mental Scales), body length and weight, disease prevalence, clinical signs of allergies, and number of children in the family. Results showed that within the underprivileged group, there was evidence that breast-feeding promoted physical growth, sensory motor development, and resistance to infection. In mothers of both male and female infants who breast-fed, there was a protective effect against subsequent pregnancy up to ten months. Therefore, among the underprivileged in developing countries, every effort should be made to prolong breast-feeding and to assist mothers with health and nutrition education.

[Low birth-weight neonates in Tunisia (author's transl)]

From a prospective analysis performed in a maternity-hospital in Tunis, incidence, characteristic features and etiologic factors responsible for birth-weight below 2,5000 g have been studied. Incidence of low birth-weight is accepted as an indicator of the level of health care in a country; this incidence, established from 6,028 living births was 7.2%, similar to that in developed countries. On the contrary, intra-uterine growth retardation rates of 69.6% and prematures rates of 30.4% are closer to those in developing countries. Altogether, anomalies of height and of the height/head circumference ratio were present in 36 children only and, in 12 out the these, abnormalities of the placenta or membranes or evidence of fetal disease were found. A factor responsible for low birth weight was found in 182 neonates: previous severe disease in the mother (7.7%), toxemia (9.4%) twin pregnancy (22.41%), fetal pathology (3.5%) and pathology of the placenta and membranes (4.6%).