Clinical and primary evidence of silver diamine fluoride on root caries management

Root caries is a growing problem for the worldwide aging population. Silver diamine fluoride (SDF) contains high concentrations of silver and fluoride ions, which prevents and arrests root caries, as well as dentin caries in the primary teeth of young children. Unlike other fluoride products that mainly reduce the formation of new carious lesions, 38% SDF is an effective agent that can efficiently arrest the carious process, remineralize the decayed dental tissues, and protect the tooth structure against the formation of new caries lesions. The use of SDF can result in more caries-resistant tooth structures. Despite these merits, its clinical disadvantages are the deep penetration of silver ions and sequential formation of silver compounds, which cause esthetic concern due to the discoloration and impaired efficacy of dentin bonding after using SDF. Thus, this narrative review, by addressing the primary experimental results and clinical applications of SDF on root caries, proposes management methods for root caries in conjunction with the application of SDF. We propose a two-visit treatment protocol to take advantage of the SDF application for root surface caries and utilize the discoloration caused by SDF.

P-763 effect of duration of cryo-storage of vitrified embryos on obstetric and perinatal outcomes

Study question

Does the duration of cryo-storage of vitrified embryos affect obstetric and perinatal outcomes?

Summary answer

Duration of cryo-storage with an open vitrification system did not affect obstetric and perinatal outcomes.

What is known already

Frozen-thawed blastocyst transfer has been performed widely with improvement of embryo culture conditions and cryopreservation techniques. Although blastocyst vitrification has become an essential method to improve clinical outcomes of IVF, there has been little study into the relationship between a long duration of cryo-storage in liquid nitrogen and obstetric and perinatal outcomes.

Study design, size, duration

This retrospective study was conducted at Kyono ART Clinic from January 2007 to December 2020. This study includes a total of 1053 singletons derived from 2461 frozen-thawed blastocyst transfers in 2461 patients. Steel’s multiple comparison test was performed for clinical and perinatal outcomes with cases of cryo-storage of less than 3 months as a control group. P < 0.05 was considered statistically significant.

Participants/materials, setting, methods

The subjects are patients who underwent their first single frozen-thawed blastocyst transfer (FBT) with an open vitrification system. Females >40 years old at cryopreservation and those who underwent preimplantation genetic testing were excluded. According to cryo-storage duration, patients were grouped as follows: group A, 0-3 months (1255 cycles); group B, 3-6 months (1008 cycles); group C, 6-12 months (162 cycles), group D, 12-24 months (36 cycles).

Main results and the role of chance

Both the mean maternal age at blastocyst cryopreservation (A: 33.7±3.6, B: 34.1±3.5, C: 34.8±3.2, D: 35.1±3.3) and the mean maternal age at FBT (A: 33.8±3.6, B: 34.4±3.5, C: 35.5±3.1, D: 36.4±3.3) in groups B, C, and D were significantly higher compared to those in group A.. There was no significant difference in the survival rate after blastocyst thawing [A: 97.4% (1256/1290), B: 98.3% (1010/1027), C: 99.4% (163/164), D: 97.2% (35/36)]. The pregnancy rate in group C was significantly lower compared to group A [A: 60.0% (752/1254), B: 61.4% (619/1008), C: 48.1% (78/162), D: 63.9% (23/36)] The gestational age of group C was significantly lower compared to group A (A: 39.5±1.8, B: 39.4±1.8, C: 38.4±3.1, D: 39.8±1.6), but there were no significant differences in live birth weight or height. There were no significant differences in congenital abnormality rate [A: 1.3% (7/541), B: 2.5% (11/440), C: 1.8% (1/56), D: 0.0% (0/16)], placental abnormalities such as placenta previa [A: 1.3% (7/541), B: 1.6% (7/440), C: 1.8% (1/56), D: 0.0% (0/16)], perinatal abnormalities such as hypertensive disorders of pregnancy or gestational diabetes [A: 6.1% (33/541), B: 8.6% (38/440), C: 1.8% (1/56), D: 6.3% (1/16)] among the four groups.

Limitations, reasons for caution

We could not provide sufficient information on confounding factors such as smoking habits, and the sample size was too small for multivariate analysis. The safety of longer storage will need to be verified as this has not been clarified in this study.

Wider implications of the findings

The pregnancy rate in group C was significantly lower than that in group A, but the effect was small: 0.065, power of 0.78. Our data suggested that the duration of cryopreservation with an open vitrification system in liquid nitrogen did not affect obstetric or perinatal outcomes.

Trial registration number

not applicable

Corticosteroid suppresses urea-cycle-related gene expressions in ornithine transcarbamylase deficiency

Background

Ornithine transcarbamylase deficiency (OTCD) is most common among urea cycle disorders (UCDs), defined by defects in enzymes associated with ureagenesis. Corticosteroid administration to UCD patients, including OTCD patients, is suggested to be avoided, as it may induce life-threatening hyperammonemia. The mechanism has been considered nitrogen overload due to the catabolic effect of corticosteroids; however, the pathophysiological process is unclear.

Methods

To elucidate the mechanism of hyperammonemia induced by corticosteroid administration in OTCD patients, we analyzed a mouse model by administering corticosteroids to OTC^spf−ash mice deficient in the OTC gene. Dexamethasone (DEX; 20 mg/kg) was administered to the OTC^spf−ash and wild-type (WT) mice at 0 and 24 h, and the serum ammonia concentrations, the levels of the hepatic metabolites, and the gene expressions related with ammonia metabolism in the livers and muscles were analyzed.

Results

The ammonia levels in Otc^spf−ash mice that were administered DEX tended to increase at 24 h and increased significantly at 48 h. The metabolomic analysis showed that the levels of citrulline, arginine, and ornithine did not differ significantly between Otc^spf−ash mice that were administered DEX and normal saline; however, the level of aspartate was increased drastically in Otc^spf−ash mice owing to DEX administration (P < 0.01). Among the enzymes associated with the urea cycle, mRNA expressions of carbamoyl-phosphate synthase 1, ornithine transcarbamylase, arginosuccinate synthase 1, and arginosuccinate lyase in the livers were significantly downregulated by DEX administration in both the Otc^spf−ash and WT mice (P < 0.01). Among the enzymes associated with catabolism, mRNA expression of Muscle RING-finger protein-1 in the muscles was significantly upregulated in the muscles of WT mice by DEX administration (P < 0.05).

Conclusions

We elucidated that corticosteroid administration induced hyperammonemia in Otc^spf−ash mice by not only muscle catabolism but also suppressing urea-cycle-related gene expressions. Since the urea cycle intermediate amino acids, such as arginine, might not be effective because of the suppressed expression of urea-cycle-related genes by corticosteroid administration, we should consider an early intervention by renal replacement therapy in cases of UCD patients induced by corticosteroids to avoid brain injuries or fatal outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02213-0.

The bacteriostatic effect of erythritol on canine periodontal disease-related bacteria

Erythritol helps both prevent and improve periodontal disease and is therefore widely used for dental care in humans. However, only a few studies have investigated the effects of erythritol on periodontal disease in animals. We hypothesized that erythritol could be used to prevent and improve periodontal disease also in canines and investigated the effects of erythritol on canine periodontal disease-related pathogenic bacteria using both in vitro and in vivo methods. The effect of erythritol on the proliferation of Porphyromonas gulae, which is reportedly associated with canine periodontal disease, was investigated in vitro. In addition, a 4-week intervention trial using an external gel preparation containing 5% erythritol was performed in canines with mild periodontal disease; changes in the microbiota around periodontal lesions were investigated using next-generation sequencing and bioinformatics analysis. The growth of P. gulae was significantly suppressed by erythritol in vitro. In the intervention study, the Shannon index, an indicator of the species distribution α-diversity, and the occupancy of several canine periodontal disease - related bacteria ( P. gulae, P. cangingivalis) were significantly decreased in periodontal lesions. Based on the results of in vitro and in vivo studies, we conclude that, as in humans, erythritol has bacteriostatic effects against periodontal disease - related bacteria in canines.

Do radiological findings around the Fitmore stem change over time?

Aims

Although the short stem concept in hip arthroplasty procedure shows acceptable clinical performance, we sometimes get unexplainable radiological findings. The aim of this retrospective study was to evaluate changes of radiological findings up to three years postoperatively, and to assess any potential contributing factors on such radiological change in a Japanese population.

Methods

This is a retrospective radiological study conducted in Japan. Radiological assessment was done in accordance with predetermined radiological review protocol. A total of 241 hips were included in the study and 118 hips (49.0%) revealed radiological change from immediately after surgery to one year postoperatively; these 118 hips were eligible for further analyses. Each investigator screened whether either radiolucent lines (RLLs), cortical hypertrophy (CH), or atrophy (AT) appeared or not on the one-year radiograph. Further, three-year radiographs of eligible cases were reviewed to determine changes such as, disappeared (D), improved (I), stable (S), and progression (P). Additionally, bone condensation (BC) was assessed on the three-year radiograph.

Results

CH was observed in 49 hips (21.1%), AT was observed in 63 hips (27.2%), and RLLs were observed in 34 hips (14.7%) at one year postoperatively. Among 34 hips with RLLs, 70.6% showed change of either D or I on the three-year radiograph. BC was observed in younger patients more frequently.

Conclusion

The Fitmore stem works well in a Japanese population with favourable radiological change on hips with RLLs. Longer-term follow-up is required to determine clinical relevance.

Cite this article: Bone Jt Open 2022;3(1):20–28.

Fibronectin plays a major role in hypoxia-induced lenvatinib resistance in hepatocellular carcinoma PLC/PRF/5 cells

Resistance to lenvatinib mesylate (LEN), a systemic chemotherapy that can be administered orally, has been a major issue for treatment of hepatocellular carcinoma (HCC). Although HCC is the tumor that most exhibits intratumoral hypoxia, which has been shown to be involved in the development of treatment resistance, there are no reports of LEN resistance in HCC treatment under hypoxia. The purpose of our study was to elucidate the mechanism of treatment resistance to LEN under hypoxia using HCC cell lines. We confirmed LEN resistance under hypoxic conditions in HCC cell lines. There was a significant increase in the IC₅₀ value of PLC/PRF/5 cells from 13.0±0.8 μM in normoxia to 21.3±1.1 μM in hypoxia, but in HepG2 cells, the increase was not significant. To elucidate the LEN resistance mechanism of PLC/PRF/5 cells under hypoxia, we performed microarray analysis and extracted genes that are thought to be related to this mechanism. Furthermore, in-silico analysis confirmed significant changes in the extracellular matrix, and among them, FN1 encoding fibronectin was determined as the hub of the gene cluster. The expression of fibronectin in PLC/PRF/5 cells examined with immunofluorescence staining was significantly elevated in and outside of cells under hypoxia, and tended to decrease when cells were exposed to LEN under normoxia. Furthermore, the fibronectin concentration in the culture solution of PLC/PRF/5 cells examined by ELISA was 2.3 times higher under hypoxia than under normoxia under LEN(-) conditions, and 1.6 times higher under hypoxia than under normoxia under LEN(+) conditions. It is assumed that in PLC/PRF/5 cells, fibronectin is probably suppressed as an indirect effect of LEN under normoxia, but transcription factors such as HIF-1α are induced under hypoxia, thus enhancing the production of fibronectin and attenuating the effect of LEN, resulting in drug resistance. This behavior of fibronectin with LEN exposure under hypoxia is probably specific to PLC/PRF/5 cells. Further studies should verify the combined effective inhibition of fibronectin and the MAPK pathway as a promising therapeutic strategy to enhance the value of LEN in HCC treatment.

Search for B^{+}→K^{+}νν[over ¯] Decays Using an Inclusive Tagging Method at Belle II

A search for the flavor-changing neutral-current decay B^{+}→K^{+}νν[over ¯] is performed at the Belle II experiment at the SuperKEKB asymmetric energy electron-positron collider. The data sample corresponds to an integrated luminosity of 63  fb^{-1} collected at the ϒ(4S) resonance and a sample of 9  fb^{-1} collected at an energy 60 MeV below the resonance. Because the measurable decay signature involves only a single charged kaon, a novel measurement approach is used that exploits not only the properties of the B^{+}→K^{+}νν[over ¯] decay, but also the inclusive properties of the other B meson in the ϒ(4S)→BB[over ¯] event, to suppress the background from other B meson decays and light-quark pair production. This inclusive tagging approach offers a higher signal efficiency compared to previous searches. No significant signal is observed. An upper limit on the branching fraction of B^{+}→K^{+}νν[over ¯] of 4.1×10^{-5} is set at the 90% confidence level.

Dialogue as therapy: the role of the expert in the ICRP Dialogues

Science communication is commonly framed as a battle with ignorance and the field of radiological protection is not exempt from this tendency. By correcting deficits in the public's understanding of science, the expert is often imagined to be able to convince the public of its objective safety ('anzen'), thereby inspiring a sense of calm ('anshin'). In the wake of the 2011 Fukushima Daiichi disaster, however, the International Commission on Radiological Protection has sought to break with this tradition by organising a series of participatory seminars in which experts engage those affected by the disaster as equals. Drawing on ethnographic fieldwork, this article suggests that the Dialogue seminars can be best understood using the metaphor of therapy; using it to describe the premise, form, and objectives of the Dialogues with a view to identifying good practice for future radiological protection scenarios.

Clinical results of a short stem with flat tapered wedge design in primary total hip arthroplasty for hip dysplasia in Asians

BACKGROUND

Cementless femoral reconstruction is challenging in hip dysplasia due to deformity of the proximal femur causing insufficient stem fixation and/or inadequate neck anteversion. Strategies to address these problems include the use of a modular stem or a distal fixation stem, but both stems have some characteristic disadvantages.

METHODS

We studied the postoperative clinical outcomes in primary total hip arthroplasty in 257 hips using the flat tapered wedge short femoral stem for hip dysplasia in an Asian population (postoperative follow-up period: 2 years to 6 years and 11 months; mean 4 years and 5 months). We took advantage of the characteristic of high flexibility in stem placement because of its low volume, positioning it while performing some varus/valgus and rotational alignment adjustments.

RESULTS

Favorable clinical functional outcomes were obtained, including the radiographic outcome of biological fixation achieved in all stems. Regarding complications, there was no case of split fracture of the femoral calcar region during stem insertion, and the rate of postoperative dislocation was also low at 0.4% (1 case). In the pre- and postoperative computed tomography measurements, the variability in stem anteversion postoperatively was significantly reduced compared to preoperative anatomical anteversion.

CONCLUSION

This flat-shaped short low-volume stem likely has high flexibility in positioning in cases of hip dysplasia and can be easily positioned to avoid fractures while still achieving secure fixation.

Evaluation of the stability of Yamakagashi (Rhabdophis tigrinus) Equine Antivenom after 20 years storage

In 2000, an equine Yamakagashi (Rhabdophis tigrinus) antivenom (Lot 0001) was testmanufactured as an unapproved drug for treatment of Yamakagashi bites. It was stocked on the premise of super-legal use from the viewpoint of emergency health crisis management. The antivenom showed a strong neutralizing ability against the hemorrhagic and coagulation activity of the Yamakagashi venom in its potency test. One vial of the antivenom can effectively neutralize at least about 4 mg of Yamakagashi venom. Its efficacy has also been confirmed in patients with severe cases of R. tigrinus bite that has been used in emergency. In 2020, this antivenom (Lot 0001) has reached 20 years after its production. To evaluate the integrity and potency of the antivenom, quality control, safety and potency tests had been conducted almost every year since 2012. Physical and chemical tests (property test, moisture content test, insoluble foreign matter test, osmotic pressure ratio test, pH test, protein content test, endotoxin test, sterility test) of the antivenom, showed no significant changes throughout the years, when compared to the results immediately after its production in 2000. All the parameters measured were also within the standard values. In animal safety tests (test for absence of toxicity and pyrogen), there was no change in the test results during the storage period and no abnormalities were observed. The potency test (anti-coagulant activity) after 20 years of the product, showed the same potency as those recorded immediately after production. Therefore, in all of the stability monitoring tests conducted so far, the product did not show any significant change compared to the results immediately after production. This confirms the stability of the product during the stockpiling period to the present, that is, 20 years after production.

POS0868 THE FORMULA TO PREDICT TACROLIMUS CONCENTRATION ACCORDING TO GENOTYPING OF CYP3A5 IS USEFUL FOR EFFECTIVE TREATMENT IN INTERSTITIAL LUNG DISEASE WITH DERMATOMYOSITIS

Background:

Tacrolimus (TAC), an immunosuppressant, can be used in second-line maintenance therapy for interstitial lung disease (ILD) in patients with dermatomyositis (DM) [1]. Although some studies reported the clinical efficacy of initial high-trough levels of TAC in combination with GC and IVCY in induction therapy for severe DM-ILD [2], there have been no useful clinical tools for deciding suitable initial dose of TAC. Genotype of polymorphisms in cytochrome P450 (CYP) 3A5 enzyme was reported to play an important role in pharmacokinetics of TAC [3], and we made a formula for deciding initial dose of TAC according to CYP3A5 genotypes in our previous study.

Objectives:

In our previous study (retrospective study), we set the target trough according to the severity for nine DM-ILD patients, six of whom were CYP3A5 *3/*3 and investigated the dose of TAC that could attain the trough using their CYP3A5 genootyping. Using these results, we developed a formula for deciding initial daily dose of TAC (target trough*weight / [(151.1, if CYP3A5 *3/*3) or (86.5, if CYP3A5 *1 allele)]). In this study, we prospectively examined the usefulness and accuracy of this formula.

Methods:

We introduced TAC for new six DM-ILD patients who visited our hospital between November 2019 and May 2020 (prospective study). The starting dose of TAC was decided by using the formula. We assessed the association between predicted and observed trough concentration of TAC at first measurement date (from day 2 to day4), using linear regression analysis. We also assessed the days for attaining the target trough concentration between the patients using the formula (prospective group) and six patients with CYP3A5 *3/*3 (retrospective group).

Results:

CYP3A5 genotype of all six DM-ILD patients were *3/*3 and underwent the TAC treatment by using the formula. The predicted and observed trough concentration of first measurement date were significantly correlated in the patients (r 2= 0.897, p=0.0041) (Fig.1). Compared with our retrospective study, target trough was more quickly attained in patients of the prospective study (Fig.2).

Conclusion:

The formula which we made for attainment target trough concentration based on CYP3A5 genotype was useful for deciding the starting dose of TAC. We also showed that we could attain the target trough concentration at early stage of initial treatment by using the formula.

References:

[1]Oddis CV and Aggarwal R. Nat Rev Rheumatol 2018;14(5):279-89.

[2]Suzuka T et al. Int J Rheum dis 2019;22: 303-13.

[3]Y. Muraki et al. Exp Ther Med 2018;15:532-38.

Figure 1.

Correlation of predicted and observed tacrolimus trough concentration at first measurement in the prospective study

Figure 2.

Days to attain the target trough concentration of tacrolimus in the prospective group and the retrospective group

Disclosure of Interests:

None declared

Micro-CT assessment of the effect of silver diammine fluoride on inhibition of root dentin demineralization

This study evaluated the ability of different types of silver diammine fluoride (SDF) to inhibit dentin demineralization using micro-focused X-ray computed-tomography (µCT). Dentin specimens were divided into five groups (n=10); no-treatment (control), 3.8% SDF (RC), 38% SDF, 38% SDF with potassium iodide (SDF/KI), and potassium fluoride (KF). The treated-dentin surfaces were subjected to demineralization for 7-days and assessed using µCT to determine mineral loss (ML) values. Specimens were also analyzed with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The ML values of the SDF and KF groups were significantly lower than those of the RC and SDF/KI groups. EDS detected fluoride ions in the SDF and KF groups but not in the RC and SDF/KI groups. It was concluded that 38% SDF demonstrated a high ability to inhibit dentin demineralization while additional application of KI may diminish the inhibitory effect of SDF. The amount of dentin demineralization with SDF treatments was material dependent.

Effects of silver diamine fluoride preparations on biofilm formation of Streptococcus mutans

Effects of silver diamine fluoride preparations (SDFs) on cariogenic biofilm formation on root dentin (RD) were investigated. Streptococcus mutans (S. mutans) biofilms were formed on bovine RD blocks coated with one of three the SDFs (38%-SDF, 3.8%-SDF and 35%-SDF+potassium-iodide; SDF+KI) and a non-coated Control which were quantified (spectrometric-measurement) and thickness measured (optical coherence tomography) after 20 h. Bacterial viability test (BacLight) and biofilm-morphometry (SEM) of 2 h biofilms were also performed. The amounts of biofilms (bacteria and water insoluble glucan) and the thickness of biofilm were minimum on 38%-SDF specimen; 3.8%-SDF and SDF+KI had significantly more than that, but had significantly less than Control (p<0.05). Most S. mutans cells found dead and morphology damaged by 38%-SDF. Some dead bacteria and remarkably damaged biofilms were observed in case of 3.8%-SDF and SDF+KI. Inhibition potential of 3.8%-SDF and SDF+KI on S. mutans biofilm formation is almost similar, although not equivalent to 38%-SDF.