Effect of fatty acids on the accelerated sulfur vulcanization of rubber by active zinc/carboxylate complexes

The effect of fatty acids with different aliphatic chain lengths on the accelerated vulcanization reaction of isoprene rubber was investigated through the generation of new intermediates composed of dinuclear bridging bidentate zinc/carboxylate complexes. Using the combination of in situ time-resolved Fourier-transform infrared spectroscopy and in situ time-resolved zinc K-edge X-ray absorption fine structure spectroscopy, the essential complex structure of the intermediates formed during the vulcanization reaction of isoprene rubber was determined to be independent of the aliphatic chain length of fatty acids. However, the reactivity of arachidic acid with ZnO was found to be low, which prolonged the induction period and curing time, and slowed down the curing rate in the vulcanization of isoprene rubber. These results help to understand the complicated vulcanization reaction of rubber, especially natural rubber, which inherently contains various fatty acids. The results obtained in this study are important for developing well-designed high-performance natural rubber products in the future.

The effect of fatty acids with different aliphatic chain lengths on the accelerated vulcanization reaction of isoprene rubber was investigated through the generation of new intermediates composed of dinuclear bridging bidentate zinc/carboxylate complexes.     

Multisystem Inflammatory Syndrome in Adults Accompanied with Kikuchi-Fujimoto Disease

We herein report a case of multisystem inflammatory syndrome in adults (MIS-A) complicated with Kikuchi-Fujimoto disease (KFD). A previously healthy 41-year-old man presented with painful swelling of the cervical lymph nodes, fever, diarrhea, conjunctivitis, edema, and hypotension one month after the onset of asymptomatic coronavirus disease 2019. Laboratory investigations revealed an elevation of CRP, and echocardiography indicated diastolic dysfunction. We diagnosed the patient to have MIS-A. Histopathology of the lymph nodes showed necrotizing lymphadenitis. After the initiation of hydrocortisone and diuretics, his symptoms resolved immediately. This case suggested that post-viral immune dysregulation in MIS-A could play a role in the etiology of KFD.     

Columnar metaplasia in the remnant esophagus is a long-term indicator for pneumonia after radical esophagectomy

Background

This study investigated the long-term risk factors for pneumonia after esophageal reconstruction using a gastric tube via the posterior mediastinal route following esophagectomy for esophageal cancer. The influence of columnar metaplasia in the remnant esophagus was specifically assessed.

Methods

Among 225 patients who underwent esophagectomy between January 2004 and December 2010, the subjects were 54 patients who could be followed up for more than 5 years. Routine oncologic follow-up consisted of CT scanning of the abdomen and chest every 4–6 months and annual endoscopy. Data on the occurrence of pneumonia were collected by retrospective review of chest CT scans. Risk factors for pneumonia investigated by univariate and multivariate analyses included the age, gender, diameter of the stapler, length of the intrathoracic remnant esophagus, anastomotic stricture, and presence of columnar metaplasia in the remnant esophagus.

Results

The median age was 62.4 years (interquartile range: 55.8–68.0 years). Forty-three patients were men. Pneumonia was detected in 39 patients (72.2%). The incidence of columnar metaplasia in the remnant esophagus increases with time. Anastomotic stricture was significantly related to the absence of columnar metaplasia on endoscopy in the first year after esophagectomy (p = 0.013). Univariate analysis showed that the frequency of pneumonia was significantly related to the intrathoracic remnant esophagus length ≥4.4 cm (p = 0.014), age over 65 years (p = 0.014), and the presence of columnar metaplasia in the remnant esophagus in the fifth year after esophagectomy (p = 0.005). Among them, age over 65 years and the presence of columnar metaplasia in the remnant esophagus in the fifth year after esophagectomy were found to be independent indicators of the postoperative pneumonia by multivariate analysis.

Conclusion

Pneumonia occurred in 72.2% (39/54) of patients after esophagectomy for esophageal cancer. The presence of columnar metaplasia after esophagectomy is an indicator for pneumonia over the long term.

     

Efficacy of Combination Antifungal Therapy with Intraperitoneally Administered Micafungin and Aerosolized Liposomal Amphotericin B against Murine Invasive Pulmonary Aspergillosis

Targeted intrapulmonary delivery of drugs may reduce systemic toxicity and improve treatment efficacy. In the current study, we evaluated the effects of a combination treatment consisting of inhalation of aerosolized liposomal amphotericin B (L-AMB) with intraperitoneal administration of micafungin (MCFG) against murine invasive pulmonary aspergillosis. The combination of aerosolized L-AMB with intraperitoneal MCFG significantly improved the survival rate, and the fungal burdens and histopathology findings after this treatment were superior to those of the control and both monotherapy groups.Invasive pulmonary aspergillosis (IPA) results in significant morbidity and mortality in severely immunocompromised patients (6). Targeted intrapulmonary delivery of antifungals has the potential to reduce systemic toxicity and improve treatment efficacy as well as prophylaxis (1, 8) and may be used as an optional route in combination with other systemic antifungals. In the current study, we evaluated the efficacy of aerosolized liposomal amphotericin B (L-AMB) both singly and in combination with intraperitoneally administered micafungin (MCFG) in a murine model of IPA.Aspergillus fumigatus MF13 was clinically obtained from a patient admitted to the Nagasaki University Hospital. The minimum effective concentration of MCFG (Astellas Pharmaceuticals Inc., Tokyo, Japan) and the MIC of AMB (Sigma, St. Louis, MO) were determined using the microdilution method in accordance with Clinical Laboratory Standards Institute document M38-A2 (2). Drug interactions were assessed using the checkerboard titration broth microdilution-based method (3), and the fractional inhibitory concentration index was determined as previously described (5).Six-week-old female ICR mice (Charles River Breeding Laboratories, Shiga, Japan) were immunosuppressed and then challenged on day 0 with 5 × 10⁶ conidia of A. fumigatus MF13 intratracheally for monitoring of survival, as previously described (7, 11). Eight-week-old female ICR mice were used to determine fungal burdens and for histopathological examination. Mice were immunosuppressed by subcutaneous injection of cortisone acetate (Sigma, Tokyo, Japan) at 250 mg/kg of body weight and intraperitoneally administered cyclophosphamide (Sigma) at 200 mg/kg on days −2 and 0 for the survival study. Only cortisone acetate (200 mg/kg) was used on days −1, 0, and 1 for fungal-burden analysis and histopathological examination. Mice were assigned into the following groups: (i) control mice, (ii) mice receiving MCFG intraperitoneally, (iii) mice receiving aerosolized L-AMB, and (iv) mice receiving a combination treatment of intraperitoneally administered MCFG and aerosolized L-AMB. Each group consisted of 11 and 10 mice for survival and fungal-burden analyses, respectively. MCFG was administered intraperitoneally once daily at 1 mg/kg/day. L-AMB was administered once daily in an 8-ml suspension (at 1.2 mg/ml) per inhalation. Antifungals were initiated 16 h after inoculation and continued for 5 and 3 days for survival and fungal-burden analyses, respectively. The L-AMB solution was aerosolized using a nebulizer (Muromachi Kikai Co., Ltd., Tokyo, Japan), and mice were exposed to aerosol treatment for 60 min as previously described (9). Control mice were treated with sterile saline. Survival was observed until 11 days following the challenge. For fungal-burden and histopathological examinations, mice were sacrificed 4 h after the treatment on day 3. Numbers of CFU per lung tissue were calculated, and removed lungs were fixed and stained with Grocott''s methenamine silver nitrate and hematoxylin-eosin as previously described (11). Survival and fungal burden data are presented from a combination of two sets of experiments. The concentration in blood and the pharmacokinetics of aerosolized L-AMB were evaluated. Uninfected mice were also exposed to several concentrations of aerosolized L-AMB for 5 days, and blood samples and lungs were collected. AMB concentration was quantified as previously described (10). Survival curves were generated using the Kaplan and Meier method, and statistical differences were evaluated by the log rank test. To assess fungal burden in lung tissue, geometric means of numbers of CFU per organ were compared by Student''s t test. Statistical significance was defined as a P of <0.05.The MIC of AMB against A. fumigatus MF-13 was 1.0 μg/ml, and the minimum effective concentration of MCFG was 0.0315 μg/ml. The fractional inhibitory concentration index of AMB and MCFG was 1.5, and drug interaction was classified as indifferent (5).Survival periods of monotherapy groups, in which mice either were treated with intraperitoneally administered MCFG or inhaled aerosolized L-AMB were significantly longer than that of the control group (MCFG alone versus the control, P = 0.006; L-AMB versus the control, P < 0.001) (Fig. ​(Fig.1).1). The combination treatment group showed significantly longer survival than the intraperitoneal-MCFG (P < 0.001), aerosolized-L-AMB (P = 0.037), and control (P < 0.001) groups. Numbers of CFU in the lungs of mice in the combination treatment group were significantly reduced compared to those in each of the intraperitoneal-MCFG (P < 0.001), aerosolized-L-AMB (P = 0.027), and control (P < 0.001) groups (Fig. ​(Fig.2).2). The lungs of aerosolized-L-AMB-administered and combination treatment mice showed obviously smaller numbers of hyphae and fewer foci of inflammation than the intraperitoneal-MCFG and control groups (Fig. ​(Fig.3).3). The mean AMB concentrations in the lung tissue following L-AMB inhalation at 1.2, 2.6, and 4.0 mg/ml were 35.5, 73.2, and 94.2 μg/g, respectively. Recorded levels in sera were 0.02, 0.06, and 0.06 μg/ml when inhaled-L-AMB suspensions were administered at 1.2, 2.6, and 4.0 mg/ml, respectively.Open in a separate windowFIG. 1.Survival curves for mice with IPA (Kaplan-Meier plot). Groups of 11 mice were treated with a combination of intraperitoneal administration of MCFG (1 mg/kg/day) and inhalation of aerosolized L-AMB (8 ml at 1.2 mg/ml [open squares]), inhalation of aerosolized L-AMB (8 ml at 1.2 mg/ml [filled triangles]), intraperitoneal administration of MCFG (1 mg/kg/day [open triangles]), and no therapy (control [filled circles]). *, P < 0.05 versus the control; **, P < 0.05 versus the control group, intraperitoneal-MCFG group, or aerosolized-L-AMB group (log rank test). The survival times for all treatment groups were longer than that for controls (P < 0.05). The survival time for the combination treatment group was significantly longer than those of the intraperitoneal-MCFG group and the aerosolized-L-AMB group (P < 0.05).Open in a separate windowFIG. 2.Numbers of CFU from homogenized lung tissues of mice with IPA. Groups of 10 mice were treated once per day with a combination of intraperitoneally administered MCFG (1 mg/kg/day) and inhalation of aerosolized L-AMB (8 ml at 1.2 mg/ml), aerosolized L-AMB (8 ml at 1.2 mg/ml), intraperitoneal MCFG (1 mg/kg/day), and saline (control). CFU counts, as a parameter of A. fumigatus burden in the lungs of IPA mice at 4 h after day 3 of treatment, are shown. *, P < 0.05 (Student''s t test).Open in a separate windowFIG. 3.Histopathology of lung tissues. Both lungs were obtained from IPA mice 4 h after 3 days of treatment with a combination of intraperitoneally administered MCFG and inhalation of aerosolized L-AMB, aerosolized L-AMB, intraperitoneal MCFG, and saline alone as a control. The lungs obtained from aerosolized-L-AMB-treated and combination treatment mice showed obviously smaller numbers of hyphae and fewer foci of inflammation than intraperitoneal-MCFG and control mice. HE, hematoxylin-eosin; GMS, Grocott''s methenamine silver nitrate stain.The current study demonstrated the efficacy of monotherapy of aerosolized L-AMB in a murine IPA model. The AMB concentrations in lung tissue in our study were relatively higher but extremely lower in serum than those from another report of a murine model of intravenously administered L-AMB, although experimental conditions were not the same (10). These results suggested that systemic toxicity generally caused by AMB treatment may be reduced by L-AMB inhalation therapy.The effect of combined intraperitoneal-MCFG and aerosolized-L-AMB treatment was an enhanced survival rate, even though this drug interaction was classified as indifferent in vitro. Since 78% of all control mice died in first 3 days in a survival analysis, we changed the experimental conditions for analysis of fungal burden and histopathological examination. In this model, no mice died before euthanasia, a prerequisite for the organ CFU assay. Both fungal-burden data and histopathological findings supported the survival data in our study.Unlike in our study, Graybill et al. previously reported that combination therapy demonstrated a lack of synergistic effects following intravenous-L-AMB and intraperitoneal-MCFG treatment in a model of murine IPA (4). These discrepancies are likely due to differences between our model and Graybill et al.''s model, including (i) the route of infection, (ii) the status of immunosuppression, and (iii) the administration route of antifungal drugs. These differences also suggest that targeted intrapulmonary delivery of drugs by inhalation raises the drug concentration at the active site of infection in the lungs, thus contributing to the efficacy of combination therapy. Further comparative efficacy studies in a clinical setting are warranted.     

Risk factors associated with respiratory disorders in late preterm infants

Objective: Late preterm infants are still high risk for respiratory problems. The aim of this study was to identify risk factors associated with respiratory problems in Japanese late preterm infants.

Methods: In this retrospective multicenter study, we included singleton late preterm deliveries at 34+^0/7–36+^6/7 weeks of gestation. We excluded cases with congenital anomalies. We defined neonatal respiratory disorders (NRD) as the combination of the need for mechanical ventilation or the use of nasal continuous positive airway pressure. We examined the perinatal risk factors associated with NRD.

Results: We included 683 late preterm infants. We found that 13.7%, 6.8% and 2.6% of the infants with NRD were born at 34, 35 and 36 weeks of gestation, respectively. In a multivariate logistic regression analysis adjusting for confounders, the gestational age (GA) at birth (adjusted odds ratio 0.40 per week [95% confidence interval, 0.25–0.61]), cesarean birth (4.18 [2.11–8.84]), and a low Apgar score (33.3 [9.93–121.3]) were independent risk factors associated with NRD.

Conclusions: An earlier GA, cesarean delivery, and a low Apgar score are independent risk factors associated with NRD in singleton late preterm infants. Patients with late preterm deliveries exhibiting these risk factors should be managed in the intensive delivery setting.     

Cell type-specific involvement of RIG-I in antiviral response

Toll-like receptors (TLRs) play an important role in antiviral response by recognizing viral components. Recently, a RNA helicase, RIG-I, was also suggested to recognize viral double-stranded RNA. However, how these molecules contribute to viral recognition in vivo is poorly understood. We show by gene targeting that RIG-I is essential for induction of type I interferons (IFNs) after infection with RNA viruses in fibroblasts and conventional dendritic cells (DCs). RIG-I induces type I IFNs by activating IRF3 via IkappaB kinase-related kinases. In contrast, plasmacytoid DCs, which produce large amounts of IFN-alpha, use the TLR system rather than RIG-I for viral detection. Taken together, RIG-I and the TLR system exert antiviral responses in a cell type-specific manner.     

Comparative genomic analysis using microarray demonstrates a strong correlation between the presence of the 80-kilobase pathogenicity island and pathogenicity in Kanagawa phenomenon-positive Vibrio parahaemolyticus strains

Vibrio parahaemolyticus is a gram-negative marine bacterium. A limited population of the organisms causes acute gastroenteritis in humans. Almost all of the clinical V. parahaemolyticus isolates exhibit beta-type hemolysis on Wagatsuma agar, known as the Kanagawa phenomenon (KP). KP is induced by the thermostable direct hemolysin produced by the organism and has been considered a crucial marker to distinguish pathogenic strains from nonpathogenic ones. Since 1996, so-called “pandemic clones,” the majority of which belong to serotype O3:K6, have caused worldwide outbreaks of gastroenteritis. In this study, we used a DNA microarray constructed based on the genome sequence of a pandemic V. parahaemolyticus strain, RIMD2210633, to examine the genomic composition of 22 strains of V. parahaemolyticus, including both pathogenic (pandemic and nonpandemic) and nonpathogenic strains. More than 86% of the RIMD2210633 genes were conserved in all of the strains tested. Many variably present genes formed gene clusters on the genome of RIMD2210633 and were probably acquired through lateral gene transfer. At least 65 genes over 11 loci were specifically present in the pandemic strains compared with any of the nonpandemic strains, suggesting that the difference between pandemic and nonpandemic strains is not due to a simple genetic event. Only the genes in the 80-kb pathogenicity island (Vp-PAI) on chromosome II, including two tdh genes and a set of genes for the type III secretion system, were detected only in the KP-positive pathogenic strains. These results strongly suggest that acquisition of this Vp-PAI was crucial for the emergence of V. parahaemolyticus strains that are pathogenic for humans.     

Novel vaccine development strategies for inducing mucosal immunity

To develop protective immune responses against mucosal pathogens, the delivery route and adjuvants for vaccination are important. The host, however, strives to maintain mucosal homeostasis by responding to mucosal antigens with tolerance, instead of immune activation. Thus, induction of mucosal immunity through vaccination is a rather difficult task, and potent mucosal adjuvants, vectors or other special delivery systems are often used, especially in the elderly. By taking advantage of the common mucosal immune system, the targeting of mucosal dendritic cells and microfold epithelial cells may facilitate the induction of effective mucosal immunity. Thus, novel routes of immunization and antigen delivery systems also show great potential for the development of effective and safe mucosal vaccines against various pathogens. The purpose of this review is to introduce several recent approaches to induce mucosal immunity to vaccines, with an emphasis on mucosal tissue targeting, new immunization routes and delivery systems. Defining the mechanisms of mucosal vaccines is as important as their efficacy and safety, and in this article, examples of recent approaches, which will likely accelerate progress in mucosal vaccine development, are discussed.