Structures of Nanoconfined Liquids Determined by Synchrotron X-ray Diffraction

We have successfully performed X-ray diffraction measurements of the liquids octamethylcyclotetrasiloxane (OMCTS, a quasi-spherical-shaped molecule) and n-hexadecane (a normal alkane) confined between mica surfaces at surface separation distances (D's) from 500 nm to the hard-wall thickness (1.9 nm for OMCTS and 1.0 nm for hexadecane). At all of the studied D's, we observed diffraction peaks corresponding to their mean intermolecular spacing at q = 8.6 nm^-1 (d = 0.73 nm) for OMCTS and q = 13.6 nm^-1 (d = 0.45 nm) for n-hexadecane. The peak intensity increased at D < ca. 50 nm for OMCTS even with the decreasing distance and exhibited a local maximum at D = 17-13 nm, indicating the sharp increase in the molecular order in this distance range. The peak intensities normalized by the D and I_normalized values of OMCTS and n-hexadecane were nearly constant at D's greater than 100 nm, though they appeared to increase slightly. The increase then became more significant with decreasing D below 100 nm, and finally the I_normalized values became 120 (for OMCTS) and 160 (for n-hexadecane) at the hard wall. These results clearly demonstrated the significant increase in the structural order of OMCTS and n-hexadecane under nanoconfinement, especially below 100 nm. The fwhm values of the peaks of OMCTS and n-hexadecane showed no significant change until small distances when the confinement effect was significant. These results indicated that the increase in the structural order should be mainly ascribed to the ordering of the molecules in the parallel plane in the enhanced layered structure formed under the confinement. The viscous parameters (b₂) of OMCTS and n-hexadecane obtained from the resonance shear measurement showed no increase at D's down to ca. 7 nm. This indicated that a certain ordering of the confined molecules was required for the observable increase in the viscosity.

Denosumab-related osteonecrosis of the jaw after tooth extraction and the effects of a short drug holiday in cancer patients: a multicenter retrospective study

Pre-existing inflammation, corticosteroid therapy, periapical periodontitis, longer duration of denosumab therapy, and female sex were significantly associated with an increased risk of denosumab-related osteonecrosis of the jaw after tooth extraction in patients with cancer on oncologic doses of denosumab. A short drug holiday did not protect against this complication.

INTRODUCTION

This study retrospectively investigated the relationship between various risk factors, including brief discontinuation of denosumab, and development of denosumab-related osteonecrosis of the jaw (DRONJ) after tooth extraction in patients with cancer who were receiving oncologic doses of this agent.

METHODS

Data were collected on demographic characteristics, duration of denosumab therapy, whether or not denosumab was discontinued before tooth extraction (drug holiday), duration of discontinuation, presence of pre-existing inflammation, and whether or not additional surgical procedures were performed. Risk factors for DRONJ after tooth extraction were evaluated by univariate and multivariate analyses.

RESULTS

A total of 136 dental extractions were performed in 72 patients (31 men, 41 women) with cancer who were receiving oncologic doses of denosumab. Post-extraction DRONJ was diagnosed in 39 teeth (28.7%) in 25 patients. Tooth extraction was significantly associated with development of DRONJ only in patients with pre-existing inflammation (odds ratio [OR] 243.77), those on corticosteroid therapy (OR 73.50), those with periapical periodontitis (OR 14.13), those who had been taking oncologic doses of denosumab for a longer period (OR 4.69), and in women (OR 1.04). There was no significant difference in the occurrence of DRONJ between patients who had a drug holiday before tooth extraction and those who did not.

CONCLUSIONS

These findings suggest that inflamed teeth should be extracted immediately in patients with cancer who are receiving oncologic doses of denosumab. Drug holidays have no significant impact on the risk of DRONJ.

Effects of surface and shear forces on nano-confined smectic-A liquid crystals studied by X-ray diffraction

The orientational behavior of a smectic-A liquid crystal (4-cyano-4'-octylbiphenyl, 8CB) confined between mica surfaces as well as between silica surfaces with a nanometer scale thickness was investigated by synchrotron X-ray diffraction measurement. The crystallographic axes of two confining mica sheets were adjusted parallel to each other to induce the preferential orientation of 8CB molecules along their crystallographic axis. The silica surfaces, which were hydrophilic and amorphous and had nanometer level smoothness, were prepared on mica surfaces using a sputtering technique. The X-ray diffraction measurement revealed that the 8CB molecules, confined between mica surfaces (DHW = 1.7 nm) and between silica surfaces (DHW = ca. 2 nm), took a planar orientation (oriented its long axis parallel to the surface) and formed a lamellar structure. However, the in-plane orientation of the confined 8CB changed depending on the confining surfaces. The lamellar axis of the 8CB confined between mica surfaces uniaxially oriented most probably due to the preferential alignment of its long axis along the principal crystallographic a-axis of the mica. On the other hand, 8CB between the silica surfaces formed lamellar domains in which the lamellar axis of 8CB omnidirectionally oriented in-plane. The effect of the shear on the orientation of the nano-confined 8CB was also investigated. The lamellar axis, corresponding to the long axis of the 8CB molecules confined between the mica surfaces, rotated only ca. 3 degrees within the plane parallel to the surface by perpendicularly applying shear to the axis. The lamellar axis of the 8CB molecules between the silica surfaces showed no noticeable change by applying the shear. These results indicated that the effect of shear to align the 8CB molecules was significantly suppressed due to the confinement effect which significantly reduces the mobility of molecules as well as the alignment effect along the crystallographic axis in the case of mica. We also observed a change in the orientation of nano-confined 8CB after shear treatment at large D (= 3.3 μm).

Differential Scanning Calorimetry Study on the Adsorption of Myoglobin at Mesoporous Silicas: Effects of Solution pH and Pore Size

In the present study, pore adsorption behavior of globular myoglobin (Mb) at mesoporous silicas was examined utilizing the low-temperature differential scanning calorimetry (DSC) method. The DSC method relies on a decrease in heat of fusion for the pore water upon adsorption of Mb. The amount and structure of Mb adsorbed into the mesoporous silica were examined by DSC and optical absorption spectroscopy. The results indicated that the pore adsorption behavior of Mb strongly depended on the solution pH and pore size of mesoporous silica. For the adsorption of Mb (diameter = 3.5 nm) into mesoporous silica with narrow pores (pore diameter = 3.3 nm) at a pH ranging from 7.0 to 3.7, the penetration of both folded and denatured Mb molecules was confirmed. The folded Mb could penetrate into large mesoporous silica pores (pore diameter = 5.3 and 7.9 nm), whereas the penetration of the denatured Mb molecules was completely inhibited. The distribution of folded Mb at mesoporous silica depended on the pore size; almost all folded Mb molecules located inside mesoporous silica pores of diameters 3.3 and 5.3 nm, whereas the Mb molecules distributed at bot internal and external pore surfaces of mesoporous silica with 7.9 nm in pore diameter. These pore adsorption behaviors suggest that aggregation or stacking of the Mb molecules at the pore entrance regions of the large pores affected the pore adsorption behavior.

Multisystem Inflammatory Syndrome in Children (MIS-C) with COVID-19: Insights from simultaneous familial Kawasaki Disease cases

Recently, an increasing number of SARS-CoV-2 patients with COVID-19 syndrome, which overlaps with Kawasaki Disease (KD), have been reported, supporting the suggestion that infection is one of the triggers of KD. We summarized the reports of simultaneous familial KD cases to better understand the etiopathogenesis of both KD and Multisystem Inflammatory Syndrome in Children (MIS-C) related to COVID-19. Here we discuss the etiology of these syndromes from the point of view of infection and genetic susceptibility.

Continuous Mesoporous Aluminum Oxide Film with Perpendicularly Oriented Mesopore Channels

Mesoporous aluminum oxide (MAO) films with perpendicularly oriented cylindrical mesopores (pore diameter: ca. 10 nm) were successfully deposited on a glass substrate by a surfactant-templating approach using aluminum nitrate as an aluminum source. The perpendicular orientation of mesopores was confirmed by grazing-incidence small-angle X-ray scattering and neutron reflection experiments. The thickness of the MAO film was around 100 nm, with a surface roughness of less than 6 nm. Since the inner surface of MAO pores was positively charged, negatively charged glucose oxidase molecules could be densely loaded into the cylindrical mesopores without significant loss of enzymatic activity. The present MAO film is potentially useful as an inorganic host material for an enzyme toward the development of a biocatalytic system.

Characterization of Myoglobin Adsorption into Mesoporous Silica Pores by Differential Scanning Calorimetry

Adsorption of protein molecules into the pores of a porous material is an important process for chromatographic separation of proteins and synthesis of nanoscale biocatalyst systems; however, there are barriers to developing a method for analyzing the process quantitatively. The purpose of this study is to examine the applicability of differential scanning calorimetry (DSC) for quantitative analysis of protein adsorption into silica mesopores. For this purpose myoglobin, a globular protein (diameter: 35.2 Å) was selected, and its adsorption onto mesoporous silica powders with uniform pore diameters (pore diameters: 39 and 64 Å) was measured by adsorption assay and DSC experiments. Our results confirmed that the adsorption of myoglobin into the silica mesopores induced significant changes in the positions and areas of freezing/melting peaks of the pore water. The decrease in heat of fusion of the pore water after myoglobin adsorption could be utilized to quantify the amount of myoglobin inside the silica mesopores. The advantages of DSC include its applicability to small wet mesoporous silica samples.

Medication-related osteonecrosis of the jaw after tooth extraction in cancer patients: a multicenter retrospective study

Root amputation, immunosuppressive therapy, mandibular tooth extraction, pre-existing inflammation, and longer duration of treatment with bone-modifying agents were significantly associated with an increased risk of medication-related osteonecrosis of the jaw. Hopeless teeth should be extracted without drug holiday before the development of inflammation in cancer patients receiving high-dose bone-modifying agents.

INTRODUCTION

No studies have comprehensively analyzed the influence of pre-existing inflammation, surgical procedure-related factors such as primary wound closure, demographic factors, and drug holiday on the incidence of medication-related osteonecrosis of the jaw (MRONJ). The purpose of this study was to retrospectively investigate the relationships between these various factors and the development of MRONJ after tooth extraction in cancer patients receiving high-dose bone-modifying agents (BMAs) such as bisphosphonates or denosumab.

METHODS

Risk factors for MRONJ after tooth extraction were evaluated with univariate and multivariate analyses. The following parameters were investigated in all patients: demographics, type and duration of BMA use, whether BMA use was discontinued before tooth extraction (drug holiday), the duration of such discontinuation, the presence of pre-existing inflammation, and whether additional surgical procedures (e.g., incision, removal of bone edges, root amputation) were performed.

RESULTS

We found that root amputation (OR = 22.62), immunosuppressive therapy (OR = 16.61), extraction of mandibular teeth (OR = 12.14), extraction of teeth with pre-existing inflammation, and longer duration (≥ 8 months) of high-dose BMA (OR = 7.85) were all significantly associated with MRONJ.

CONCLUSIONS

Tooth extraction should not necessarily be postponed in cancer patients receiving high-dose BMA. The effectiveness of a short-term drug holiday was not confirmed, as drug holidays had no significant impact on MRONJ incidence. Tooth extraction may be acceptable during high-dose BMA therapy until 8 months after initiation.

Effect of Cavity Size of Mesoporous Silica on Short DNA Duplex Stability

We studied the stabilities of short (4- and 3-bp) DNA duplexes within silica mesopores modified with a positively charged trimethyl aminopropyl (TMAP) monolayer (BJH pore diameter 1.6-7.4 nm). The DNA fragments with fluorescent dye were introduced into the pores, and their fluorescence resonance energy transfer (FRET) response was measured to estimate the structuring energies of the short DNA duplexes under cryogenic conditions (temperature 233-323 K). The results confirmed the enthalpic stability gain of the duplex within size-matched pores (1.6 and 2.3 nm). The hybridization equilibrium constants found for the size-matched pores were 2 orders of magnitude larger than those for large pores (≥3.5 nm), and this size-matching effect for the enhanced duplex stability was explained by a tight electrostatic interaction between the duplex and the surface TMAP groups. These results indicate the requirement of the precise regulation of mesopore size to ensure the stabilization of hydrogen-bonded supramolecular assemblies.

Thermodynamics of Complexation between Thiourea-based Receptor and Acetate in Water/Acetonitrile Mixture

A thiourea-based receptor has been extensively studied for selective anion recognition for reasons of its strong hydrogen bond donor ability. In the present study, the thermodynamics of complexation between a thiourea-based receptor and acetate was examined in a water/acetonitrile mixture. The receptor used in this study was N,N'-bis(p-nitrophenyl)thiourea (BNPTU). UV/vis spectroscopic titration and isothermal titration calorimetry (ITC) experiments clearly revealed endothermic and entropy-driven complexation of BNPTU with acetate in water/acetonitrile mixtures. Since the endothermic peaks found in water/acetonitrile mixtures were about three times greater than those in acetonitrile, it appears that preferential hydration of both receptor and acetate was responsible for the endothermic and entropy-driven complexation reaction. The thermodynamic properties found in this study have the potential to contribute to the design of a thiourea-based anion receptor.

A multicenter retrospective study of the risk factors associated with medication-related osteonecrosis of the jaw after tooth extraction in patients receiving oral bisphosphonate therapy: can primary wound closure and a drug holiday really prevent MRONJ?

Root amputation, extraction of a single tooth, bone loss or severe tooth mobility, and an unclosed wound were significantly associated with increased risk of developing medication-related osteonecrosis of the jaw (MRONJ). We recommend a minimally traumatic extraction technique, removal of any bone edges, and mucosal wound closure as standard procedures in patients receiving bisphosphonates.

INTRODUCTION

Osteonecrosis of the jaws can occur following tooth extraction in patients receiving bisphosphonate drugs. Various strategies for minimizing the risk of MRONJ have been advanced, but no studies have comprehensively analyzed the efficacy of factors such as primary wound closure, demographics, and drug holidays in reducing its incidence. The purpose of this study was to retrospectively investigate the relationships between these various risk factors after tooth extraction in patients receiving oral bisphosphonate therapy.

METHODS

Risk factors for MRONJ after tooth extraction were evaluated using univariate and multivariate analysis. All patients were investigated with regard to demographics; type and duration of oral bisphosphonate use; whether they underwent a discontinuation of oral bisphosphonates before tooth extraction (drug holiday), and the duration of such discontinuation; and whether any additional surgical procedures (e.g., incision, removal of bone edges, root amputation) were performed.

RESULTS

We found that root amputation (OR = 6.64), extraction of a single tooth (OR = 3.70), bone loss or severe tooth mobility (OR = 3.60), and an unclosed wound (OR = 2.51) were significantly associated with increased risk of developing MRONJ.

CONCLUSIONS

We recommend a minimally traumatic extraction technique, removal of any bone edges, and mucosal wound closure as standard procedures in patients receiving bisphosphonates. We find no evidence supporting the efficacy of a pre-extraction short-term drug holiday from oral bisphosphonates in reducing the risk of MRONJ.

Preoperative prediction for regaining ambulatory ability in paretic non-ambulatory patients with metastatic spinal cord compression

STUDY DESIGN

Retrospective multicenter study.

OBJECTIVES

To analyze the predictive factors for postoperative ambulatory recovery in paretic non-ambulatory patients with metastatic spinal cord compression (MSCC).

SETTING

Japan.

METHODS

Eighty-two consecutive patients (74.4% men; mean age, 66.2 years) who could not walk before surgery due to cervical or thoracic MSCC and underwent posterior decompressive surgery between 2003 and 2014 were included. Patients were divided into two groups according to ambulatory status at 6 weeks after surgery: recovery (group R) and non-recovery (group NR). To evaluate the speed of progression of motor deficits, we assessed the period from onset of neurological symptoms to gait inability (T1).

RESULTS

Fifty patients (61.0%) regained the ability to walk (group R). The period of T1 demonstrated a positive correlation with probability of ambulatory recovery (P=0.00; Kendall's tau-b=0.38), and a receiver operating characteristic curve analysis showed that the cutoff value of T1 was 5 days (area under the curve=0.72; P=0.001). In multivariate analysis, <6 days of T1 was one of the independent risk factors for failing to regain ambulatory ability (odds ratio, 8.74; P=0.00).

CONCLUSIONS

The speed of progression of motor deficits can independently and powerfully predict the chance of postoperative ambulatory recovery as well as previously identified predictors. Since information about the speed of progression can be obtained easily by interviewing patients or family members, even if the patient is in an urgent state, our results will be helpful in clinical decision-making.

Structural Stability of Light-harvesting Protein LH2 Adsorbed on Mesoporous Silica Supports

In the present study, we examined the reversible thermal deformation of the membrane protein light-harvesting complex LH2 adsorbed on mesoporous silica (MPS) supports. The LH2 complex from Thermochromatium tepidum cells was conjugated to MPS supports with a series of pore diameter (2.4 to 10.6 nm), and absorption spectra of the resulting LH2/MPS conjugates were observed over a temperature range of 273 - 313 K in order to examine the structure of the LH2 adsorbed on the MPS support. The experimental results confirmed that a slight ellipsoidal deformation of LH2 was induced by adsorption on the MPS supports. On the other hand, the structural stability of LH2 was not perturbed by the adsorption. Since the pore diameter of MPS support did not influence the structural stability of LH2, it could be considered that the spatial confinement of LH2 in size-matches pore did not improve the structural stability of LH2.

Prospective study of dental intervention for hematopoietic malignancy

Various chemotherapeutic agents used in patients with hematopoietic malignancy cause serious side effects, including myelosuppression and immunosuppression. Immunosuppression makes patients more susceptible to infection, resulting in an increased risk of infectious complications, including the development of severe septicemia that may be life-threatening. It is necessary for dental staff to be familiar with an appropriate protocol in such cases and to share information about the chemotherapy with a hematologist. To verify the effectiveness of our dental intervention protocol, we conducted a prospective study on the incidence of complications for each myelosuppressive grade of chemotherapy in patients with hematopoietic malignancy. We compared the incidence of complications between treatment P (patients who finished all the dental treatments according to the protocol) and treatment Q (patients who did not) per grade (A, B, C, D) and incidence of systemic or oral findings. We also compared the incidence of oral complication related to the residual teeth between first chemo (patients who were undergoing chemotherapy for the first time) and prior chemo (not the first time). There were significant differences in inflammatory complications between treatment P and treatment Q. We found that both systemic and oral inflammatory complications increased with higher-grade myelosuppressive chemotherapy. Additionally, there was a significant difference between the incidence of oral complications related to the residual teeth between first chemo and prior chemo. Complete implementation of the dental intervention protocol was associated with fewer oral and systemic infectious and inflammatory complications in patients with hematopoietic malignancies undergoing chemotherapy. The incidence of oral and systemic complications also increased with grade of chemotherapy. These results support the validity of our dental intervention protocol. We should pay close attention to the oral state of de novo hematopoietic malignancy patients.

Two cases of posterior open bite caused by the thickness of retrodiscal tissue in the temporomandibular joint

There have been few reports of mouth closing disturbances in the final phase of occlusion caused by the posterior thickness of the retrodiscal tissue. Two such cases are described here. The first was a 70-year-old female suffering from a painless mouth closing disturbance on the right side of the temporomandibular joint (TMJ). She complained of a feeling like there was an air cushion. The second case was a 51-year-old male with a painless mouth closing disturbance on the left side of the TMJ. In both cases, magnetic resonance imaging (MRI) revealed enlargement of the posterior joint space on the affected side. The conditions of these two cases were improved by local injection of steroid preparations; however further additional treatments were required, including mandible traction in one case and dental prosthetics in the other. Consequently, we consider that the local injection of steroid preparations is useful as an initial treatment, while the use of local injection of steroid preparations alone is not sufficient for the treatment of posterior thickness of the retrodiscal tissue.

Sequential changes in oral dryness evaluated by a moisture-checking device in patients with oropharyngeal cancer during chemoradiotherapy: a pilot study

PURPOSE

Although oral dryness is a predictor for oral mucositis caused by Chemoradiotherapy (CRT) for head and neck cancer, there have been few reports evaluating the sequential changes in oral dryness during therapy. Studies have determined the reliability and usefulness of a moisture-checking device for the evaluation of dry mouth. This study aimed to evaluate the oral moisture level in patients with Oropharyngeal Cancer (OPC) during CRT using a moisture-checking device.

METHODS

Oral moisture level was measured with an oral moisture-checking device (Moisture Checker Mucus®) at the lingual and buccal mucosa before, at the midpoint, and at the end of CRT in patients with OPC. Sequential changes in oral dryness were evaluated.

RESULTS

A significant decrease in oral moisture level at the lingual mucosa was found when comparing values before and at the end of CRT (P=0.017). Decreases in oral moisture level at the buccal mucosa were not significant.

CONCLUSIONS

A moisture-checking device is considered a useful tool for determining the sequential changes in oral dryness during CRT for head and neck cancer. Our findings provide a basis for future larger long-term studies of oral moisture levels in OPC patients receiving CRT.

Effects of postoperative chemotherapy and radiotherapy on patients with squamous cell carcinoma of the oral cavity and multiple regional lymph node metastases

Nodal metastasis in oral squamous cell carcinoma (OSCC) is considered to be a predictor of a poor prognosis. The aim of this study was to investigate the relationship between the number of positive lymph nodes and the prognosis in OSCC patients with nodal metastases and to assess the effects of postoperative radiotherapy (RT) or concurrent chemoradiotherapy (CCRT) on this patient group. A retrospective investigation of 98 patients with OSCC who underwent radical neck dissection and had at least three pathologically positive lymph nodes was performed. The 5-year disease-specific survival rate was 66.7% for patients with 3 positive nodes, while it was significantly lower for those with 4 positive nodes and those with ≥ 5 positive nodes (21.5% and 46.1%, respectively; P < 0.01). The loco-regional control and disease-specific survival rates for the surgery alone, surgery plus RT, and surgery plus CCRT groups were 46.2% and 40.5%, 66.3% and 54.4%, and 81.7% and 52.4%, respectively. For patients with ≥ 4 positive nodes, the loco-regional control rate after surgery plus CCRT was better than that observed after surgery alone (77.5% vs. 32.6%, P = 0.01). Postoperative RT and CCRT have positive impacts on the prognosis of OSCC patients with advanced stage neck disease.

Evaluating the masticatory function after mandibulectomy with colour-changing chewing gum

The aim of this study was to clarify the usefulness of colour-changing gum in evaluating masticatory performance after mandibulectomy. Thirty-nine patients who underwent mandibulectomy between 1982 and 2010 at Kobe University Hospital were recruited in this study. There were 21 male and 18 female subjects with a mean age of 64·7 years (range: 12-89 years) at the time of surgery. The participants included six patients who underwent marginal mandibulectomy, 21 patients who underwent segmental mandibulectomy and 12 patients who underwent hemimandibulectomy. The masticatory function was evaluated using colour-changing chewing gum, gummy jelly and a modified Sato's questionnaire. In all cases, the data were obtained more than 3 months after completing the patient's final prosthesis. The colour-changing gum scores correlated with both the gummy jelly scores (r = 0·634, P < 0·001) and the total scores of the modified Sato's questionnaire (r = 0·537, P < 0·001). In conclusion, colour-changing gum is a useful item for evaluating masticatory performance after mandibulectomy.

Cytokine profile during the clinical course of toxic shock syndrome

Toxic shock syndrome (TSS) is an acute febrile disease with multiple organ involvement caused by massive and rapid release of cytokines induced by staphylococcal exotoxins. However, the precise cytokine profile is still undefined in clinical cases. We measured serum cytokine concentrations in a patient who developed TSS after a caesarean section. Measurements were taken on admission and several times during the course of the disease. Methicillin-resistant Staphylococcus aureus producing TSS toxin-1 and staphylococcal enterotoxin C was detected in the lochia and venous blood. Serum interleukin (IL)-6 level was markedly increased on admission, and IL-10, tumour necrosis factor-alpha, and interferon-gamma levels were also raised. These cytokine levels rapidly returned to normal levels. In contrast, IL-1beta and IL-2 were below the analytical sensitivity threshold throughout the course. Our data and other previous case reports indicate that a marked increase in IL-6 concentration could be a clinical marker of TSS onset.

Antineutrophil cytoplasmic antibody-associated vasculitis with oculomotor nerve palsy

We report a patient with antineutrophil cytoplasmic antibody-associated vasculitis with oculomotor nerve palsy. The patient presented with a high fever, diplopia, blepharoptosis and impairment of ocular movement of the left eye except for lateral gaze. Multiple erythematous and livedoid lesions were observed on the forehead, both cheeks and both legs. Laboratory examination showed positive results for myeloperoxidase antineutrophil cytoplasmic antibodies. Skin biopsy revealed leucocytoclastic vasculitis of the small arteries in the lower dermis. The patient was successfully treated with systemic corticosteroids.