[Second-Generation Antihistamines for Preventing Hypersensitivity Reactions during Anticancer Therapy-A Retrospective Study].

Hypersensitivity reactions are an adverse effect of anticancer drug therapy. Prophylactic administration of antiallergic drugs and steroids is recommended when administering drugs associated with a high hypersensitivity reaction incidence. First-generation antihistamines are generally used in this setting. These medications, however, induce drowsiness and sedation due to their inhibitory effects on the central nervous system. They are contraindicated in patients with angle-closure glaucoma and prostatic hyperplasia. Second-generation antihistamines are used as alternative drugs for such cases in our hospital. This study investigated the use of second-generation antihistamines at our hospital and examined their efficacy and safety. A total of 7 second-generation antihistamines were used at our hospital. Approximately 90% of the target patients were shifted from first-generation antihistamines to bilastine or desloratadine. The most frequent reasons for changing to second- generation antihistamines were drowsiness(32.3%)and car driving(24.2%). No central inhibitory side effects were observed upon consumption of second-generation antihistamines. Only 2 patients(3.2%)developed hypersensitivity reactions after changing to second-generation antihistamines. Our findings suggest that second-generation antihistamines are effective in preventing hypersensitivity reactions. These medications may be used in patients who have concerns regarding the central inhibitory side effects of first-generation antihistamines or their potential to exacerbate comorbidities. Their use can help improve the safety of anticancer drug therapy.

Association between disease severity according to "MN criteria" and 30-day mortality in patients with Clostridioides difficile infection.

INTRODUCTION: A rapid membrane enzyme immunoassays (EIA) are frequently used to diagnose Clostridioides difficile infection (CDI). If EIA does not provide a definitive CDI diagnosis, whether treatment with anti-CD agents is to be performed depends on the pathogenesis and severity of the disease. In Japan, "MN criteria" have been proposed for the classification of disease severity. In this study, we investigated the association between disease severity and CDI prognosis when MN criteria are used. METHODS: This study included 102 patients diagnosed with CDI between April 2015 and March 2020. The disease serverity classification accorditng to MN criteria was divided into two groups: non-severely ill (mild to moderate) and severely ill (severe to critical) group. RESULTS: Mortality was significantly higher in severely ill patients than non-severely ill patients (46.7% vs. 13.8%, p = 0.0025). Multivariable analysis showed that the mortality of patients with CDI was significantly associated with advanced age (odds ratio [OR] = 1.1; 95% confidence interval [CI] = 1.0-1.2; p = 0.019) and disease severity (OR = 4.2; 95% CI = 1.2-14.8; p = 0.023). DISCUSSION: The classification of disease severity according to the MN criteria would be particularly useful in predicting the patients' prognoses.

Evaluation of Remdesivir for Mildly to Moderately Ill Patients with COVID-19: A Single-Arm, Single-Center, Retrospective Study.

Background and Objectives: Remdesivir (RDV) is the first antiviral agent approved in Japan for the treatment of coronavirus disease 2019 (COVID-19). The aim of our study was to assess the efficacy and safety of RDV treatment in mildly to moderately ill patients with COVID-19. Materials and Methods: A single-center, retrospective study was performed in Fukuoka University Chikushi Hospital. Patients admitted to our hospital from June to October 2021 for RDV treatment against COVID-19 were enrolled. The primary end point was clinical status on days 10 and 14, using a 6-point ordinal scale ranging from death (category 6) to discharge (category 1). Adverse events were assessed and graded using the Japanese version of Common Terminology Criteria for Adverse Events (CTCAE) v5.0. Results: In total, 47 COVID-19 patients receiving RDV treatment were assessed during the study period. Thirty-four (72.3%) out of 47 patients required oxygen therapy. Out of these 34 patients, 30 (88.2%) showed a 2-point clinical improvement on day 14 after RDV was initiated. Serum alanine aminotransferase levels were elevated in three patients (6.4%) (CTCAE Grade 3) and neutropenia was detected in one patient (2.1%) out of the 47 patients. Conclusions: RDV may be highly effective, with good safety profiles, in patients with COVID-19 requiring oxygen therapy.

Estimating the effect of optimizing anticancer drug vials on medical costs in Japan based on the data from a cancer hospital.

BACKGROUND: The substantial increase in the use of expensive anticancer drugs has been accompanied by an increase in the amount of disposing residual liquid from drug preparations. Many Western countries, including the United States, have implemented drug vial optimization (DVO) to prevent the waste of anticancer drugs and have reported the reductions in the total drug costs. This study was designed to estimate the expected reduction in spending on anticancer drugs by Japanese cancer hospitals when DVO was implemented instead of individual preparations and to test the effectiveness of this approach. METHODS: We investigated the doses of drugs used and quantity specifications for individually prepared vials for patients who received anticancer drug treatment in December 2017 at the Outpatient Treatment Center of the National Cancer Center Hospital East. Based on these findings, we calculated the total quantity of each drug used on a given day, and the minimum cost for preparation of the number of specified combinations corresponding to the total cost (DVO preparation). Based on the differences in these two costs, we estimated the economic impact of implementing DVO. RESULTS: While the cost for anticancer drugs for the 1-month study period was US$3,305,595 (US$1 = \110) for individual preparations, the estimated cost for DVO preparations was US$3,092,955, equivalent to a reduction of US$212,640. CONCLUSIONS: Based on these study results, implementation of DVO-based preparation of injectable anticancer drugs in Japan in 2017 would have resulted in saving approximately US$460 million. This calculation revealed the need for the Japanese government to modify the methods employed to calculate drug costs in the insurance system and develop policies for the proper and optimal use of medical resources.

Acceleration of Skin Wound-Healing Reactions by Autologous Micrograft Tissue Suspension.

Background and objectives: Skin grafting is a method usually used in reconstructive surgery to accelerate skin regeneration. This method results frequently in unexpected scar formations. We previously showed that cutaneous wound-healing in normal mice is accelerated by a micrograft (MG) technique. Presently, clinical trials have been performed utilizing this technology; however, the driving mechanisms behind the beneficial effects of this approach remain unclear. In the present study, we focused on five major tissue reactions in wound-healing, namely, regeneration, migration, granulation, neovascularization and contraction. Methods: Morphometrical analysis was performed using tissue samples from the dorsal wounds of mice. Granulation tissue formation, neovascularization and epithelial healing were examined. Results: The wound area correlated well with granulation sizes and neovascularization densities in the granulation tissue. Vascular distribution analysis in the granulation tissue indicated that neovessels extended and reached the subepidermal area in the MG group but was only halfway developed in the control group. Moreover, epithelialization with regeneration and migration was augmented by MG. Myofibroblast is a known machinery for wound contraction that uses α-smooth muscle actin filaments. Their distribution in the granulation tissue was primarily found beneath the regenerated epithelium and was significantly progressed in the MG group. Conclusions: These findings indicated that MG accelerated a series of wound-healing reactions and could be useful for treating intractable wounds in clinical situations.

[A Survey on the Concurrent Administration of Erlotinib and Gastric Acid Suppressing Medications among Doctors:Concern for Drug Interaction].

Erlotinibis known as a key drug for the treatment of non-small-cell lung cancer. It is known to interact with gastric acid suppressing medications(AS). Concurrent administration of erlotinibwith AS is reported to decrease AUC and Cmax of erlotinib. From the result of a survey on concurrent administration of erlotinib with AS in our hospital, we considered that intake of erlotinib between meals in the morning and intake of AS after dinner or at bedtime certainly reduce the chance of drug interactions to a minimum. We suggested a direction of use of erlotinibto the doctors who used to prescribe this medication in their daily medical practice. We surveyed the doctors' perceptions of drug interactions. The results of the survey showed that 29% of the doctors were not concerned about drug interactions, although 81% of the doctors approved our proposal. By providing a suggestion for drug administration by analyzing drug information, the expectations of the doctors can be met and it also demonstrates the efficiency of pharmacists.

Prevalence of Slow-Growth Vancomycin Nonsusceptibility in Methicillin-Resistant Staphylococcus aureus.

We previously reported a novel phenotype of vancomycin-intermediate Staphylococcus aureus (VISA), i.e., "slow VISA," whose colonies appear only after 72 h of incubation. Slow-VISA strains can be difficult to detect because prolonged incubation is required and the phenotype is unstable. To develop a method for detection of slow-VISA isolates, we studied 23 slow-VISA isolates derived from the heterogeneous VISA (hVISA) clinical strain Mu3. We identified single nucleotide polymorphisms (SNPs) in genes involved in various pathways which have been implicated in the stringent response, such as purine/pyrimidine synthesis, cell metabolism, and cell wall peptidoglycan synthesis. We found that mupirocin, which also induces the stringent response, caused stable expression of vancomycin resistance. On the basis of these results, we developed a method for detection of slow-VISA strains by use of 0.032 µg/ml mupirocin (Yuki Katayama, 7 March 2017, patent application PCT/JP2017/008975). Using this method, we detected 53 (15.6%) slow-VISA isolates among clinical methicillin-resistant S. aureus (MRSA) isolates. In contrast, the VISA phenotype was detected in fewer than 1% of isolates. Deep-sequencing analysis showed that slow-VISA clones are present in small numbers among hVISA isolates and proliferate in the presence of vancomycin. This slow-VISA subpopulation may account in part for the recurrence and persistence of MRSA infection.

Linezolid minimum inhibitory concentration (MIC) creep in methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates at a single Japanese center.

The aim of this study was to evaluate whether linezolid minimum inhibitory concentration (MIC) creep occurred in Staphylococcus aureus clinical isolates, including methicillin-resistant S. aureus (MRSA), over a recent 5-year period at a single Japanese center. A total of 453 MRSA and 195 methicillin-susceptible S. aureus (MSSA) isolates recovered from inpatients from April 1, 2008 to March 31, 2013 were analyzed. The MIC of linezolid was determined by automated Vitek-2 system. The modal MIC, MIC range, MIC50 and MIC90 (MICs required to inhibit the growth of 50% and 90% of organisms, respectively), geometric mean MIC and percentages of susceptible and resistant isolates were evaluated for each fiscal year. None of the S. aureus isolates were resistant to linezolid. Isolates with an MIC of >1 µg/mL were more common in the MSSA samples than in the MRSA samples (91.3% versus 38.2%, p<0.001). The linezolid geometric mean MIC increased by 0.403 µg/mL (from 1.178 in 2008 to 1.582 in 2012) in the MRSA isolates (p=0.006, r(2)=0.945 according to a linear regression analysis) over the 5-year period; however, no increase was observed in the MSSA isolates. The frequency of MRSA isolates with an MIC of 1 µg/mL decreased (from 76.3% in 2008 to 35.4% in 2012) and the isolates with MICs of >1 µg/mL increased over time (from 23.7% in 2008 to 64.6% in 2012). This report demonstrates the occurrence of linezolid MIC creep, as determined using the geometric mean MIC, in MRSA clinical isolates at a single Japanese center.

Relationship between Target Time above Minimum Inhibitory Concentration Achievement Rate of Meropenem Using Monte Carlo Simulation and In-Hospital Survival in Patients with Pseudomonas aeruginosa Bacteremia.

Pseudomonas aeruginosa bacteremia is associated with a high mortality rate, and meropenem (MEPM) is commonly used to treat it. However, the relationship between the time above the minimum inhibitory concentration (fT>MIC) of MEPM and its therapeutic efficacy in P. aeruginosa bacteremia has not been explored. This study aimed to investigate this relationship by defining the target % fT>MIC of MEPM as 75%. The retrospective study spanned 14 years and included hospitalized patients treated with MEPM for P. aeruginosa bacteremia. Monte Carlo simulation was used to calculate the probability of target attainment (PTA) for each patient, and the threshold for a PTA of 75% fT>MIC associated with in-hospital survival was determined using receiver operating characteristic (ROC) curves. The ROC curve-derived PTA associated with improved in-hospital survival was 65.0%, a significant finding in multivariate logistic regression analysis adjusted for patient background factors (odds ratio: 20.49, 95% confidence interval: 3.02-245.23, p = 0.005). This result suggests a dosing regimen that achieves a PTA of at least 65% when the target fT>MIC of MEPM for treating P. aeruginosa bacteremia is defined as 75%.

Genotypic Shift and Diversification of MRSA Blood Stream Isolates in a University Hospital Setting: Evidence from a 12-Year Observational Study.

There have been few reports regarding the long-term trends in the genotypes of methicillin-resistant Staphylococcus aureus (MRSA) bloodstream isolates. Therefore, this study was performed to investigate the longitudinal trends in the genotypes of MRSA bloodstream isolates obtained from hospitalized patients during a 12-year study period from 2010 to 2021 at a tertiary care university hospital. Over the 12-year period from 2010 to 2021, we conducted a genetic investigation focusing on 245 MRSA strains isolated from the blood of hospitalized patients. The genotypes of the MRSA bloodstream isolates were determined by Staphylococcal Cassette Chromosome mec (SCCmec) typing, accessory gene regulator (agr) typing, PCR-based ORF typing (POT), and multilocus sequence typing (MLST). Strains with the same POT type detected in two or more isolates were designated as epidemic clones, while strains without a common POT type were classified as sporadic clones. Until 2015, isolates with SCCmec II/agr II were prevalent, but isolates with SCCmec IV/agr III increased from 2016. A total of 128 strains (52%) were identified as epidemic clones, while 117 strains (48%) were classified as sporadic clones. The detection rate of sporadic clones increased significantly since 2016 (p < 0.05). The epidemic clones were classified into three clusters, with MRSA of clonal complex (CC) 1 being prominent after 2016. This study showed that the genotypes of MRSA bloodstream isolates underwent a shift from SCCmec II/agr II type to SCCmec IV/agr III type, with a notable increase in MRSA of CC1, after 2016. There was a significant increase in the proportion of sporadic strains among the isolates, suggesting the diversification of genotypes.

Assessing the ability of the Cancer and Aging Research Group tool to predict chemotherapy toxicity in older Japanese patients: A prospective observational study.

INTRODUCTION: The Cancer and Aging Research Group (CARG) prediction tool was designed in the United States to predict grade ≥ 3 chemotherapy-related adverse events (CRAE) in older patients. However, its usefulness among Japanese people, who have different sensitivities to anticancer drugs and life expectancy, remains unknown. We aimed to prospectively evaluate the utility of the CARG tool for predicting severe CRAE in older Japanese patients with cancer. MATERIAL AND METHODS: Patients with solid tumors aged 65 years and older who commenced anticancer drug regimens from April 2018 to October 2020 were divided into three groups (low, medium, and high-risk) based on their CARG risk scores. Toxicity was prospectively observed by a pharmacist. The primary objective was to evaluate the correlation between the incidence of grade ≥ 3 CRAE and the CARG risk score. The secondary objective was to evaluate hematological and non-hematological toxicities. CRAE incidence was compared among the three groups using a closed testing procedure: (1) Cochran-Armitage test for trend and (2) chi-square test for paired comparison. RESULTS: The patients (N = 165) had a median age of 71 years (range: 65-89 years). CRAE in patients divided into low-, medium-, and high-risk groups, based on CARG risk scores, were 39%, 55%, and 82%, respectively (low vs high; p < 0.001, medium vs high; p < 0.01). The incidence of severe hematologic toxicity was 37%, 35%, and 50% in the low-, medium-, and high-risk groups, respectively; the incidence of severe non-hematologic toxicity was 15%, 36%, and 65%, respectively (low vs medium; p < 0.01, low vs high; p < 0.001, and medium vs high; p < 0.01). DISCUSSION: To our knowledge, this is the first prospective observational study to validate the CARG prediction tool in older Japanese patients with cancer. The CARG risk score may be effective in predicting the development of non-hematologic toxicities. These results should be considered when administering chemotherapy to older Japanese patients with advanced solid tumors.

Presence of both heterogeneous vancomycin-intermediate resistance and ß-lactam antibiotic-induced vancomycin resistance phenotypes is associated with the outcome in methicillin-resistant Staphylococcus aureus bloodstream infection.

BACKGROUND: Although the individual expression of heterogeneous vancomycin-intermediate resistance (hVISA) and ß-lactam antibiotic-induced vancomycin resistance (BIVR) phenotypes has been associated with treatment failure and recurrence in methicillin-resistant Staphylococcus aureus (MRSA) infections, the effect of the co-expression of these phenotypic profiles on clinical outcome has not been fully elucidated. The aim of this study was to determine the impact of the combination of hVISA and BIVR phenotypes on the clinical outcome in MRSA bacteremia. METHODS: One hundred and sixty-two MRSA blood isolates from a 21-y period, 1987-2007, were randomly selected. Screening for hVISA was done by the macromethod Etest and confirmed by population analysis profiles. BIVR was identified using Mu3 agar containing 4 µg/ml of vancomycin. RESULTS: Thirty (18.5%) and 39 (24.1%) of the 162 MRSA blood isolates were positive for the hVISA and BIVR phenotypes, respectively. Eighteen (11.1%) isolates possessed both hVISA and BIVR phenotypes (hVISA(+)/BIVR(+)). In a subset of patients who received initial treatment with glycopeptides, only the patients whose isolates were hVISA(+)/BIVR(+) displayed a significantly higher mortality rate in comparison to those with non-hVISA(+)/BIVR(+) (80.0% vs 31.3%, p = 0.004). The presence of both hVISA and BIVR phenotypes was a predictor of mortality using a logistic regression analysis (p = 0.025). CONCLUSIONS: The combined phenotype of hVISA and BIVR was associated with a higher probability of mortality in patients with MRSA bacteremia. Further prospective studies are warranted to delineate the clinical significance of the combined phenotype of hVISA and BIVR.

Impact of Nucleic Acid Amplification Test on Clinical Outcomes in Patients with Clostridioides difficile Infection.

A nucleic acid amplification test (NAAT) is recommended to determine whether or not patients have a Clostridioides difficile infection (CDI) when the glutamate dehydrogenase activity assay is positive and the rapid membrane enzyme immunoassays for toxins is negative. In our hospital, a NAAT was introduced to diagnose CDI precisely in April 2020. This study aimed to investigate the impact of a NAAT on the clinical outcomes in patients with CDI at our hospital. Seventy-one patients diagnosed with CDI between April 2017 and March 2022 were included in our study. Patients with CDI were divided into two groups: before (pre-NAAT) and after (post-NAAT) the introduction of NAAT. The clinical outcome was compared between the two groups. Of the 71 patients with CDI, 41 were sorted into the pre-NAAT group and 30 into the post-NAAT group. The clinical cure rate was significantly higher in the post-NAAT group compared to the pre-NAAT group (76.7% vs. 48.8%, p = 0.018). In the multivariable analysis, the clinical cure was significantly associated with the introduction of NAAT (p = 0.022). Our findings suggest that the introduction of NAAT can improve the clinical outcomes in CDI patients.

Incidence and Timing of Immune-Related Adverse Events in Immune-Checkpoint Inhibitor-Treated Patients: A Retrospective Observational Study.

BACKGROUND: Immune-checkpoint inhibitors (ICIs) are effective against various cancers; however, immune-related adverse events (irAEs) have been reported and the timing and risk factors are unknown. Therefore, we examined the incidence and timing of irAE occurrence. METHODS: Patients who received ICIs at our hospital between 1 April 2016 and 31 March 2020 were enrolled. Patients were classified into an irAE group or non-irAE group. In addition, we examined the onset time and symptoms of irAEs for each ICI type. RESULTS: A total of 80 patients received ICIs, of which 27 (33.8%) developed irAEs. The incidence of irAEs was 35.3% for nivolumab, 35.5% for pembrolizumab, and 28.6% for atezolizumab. The incidence of pneumonitis was 12.5%, 8.8% for dermatologic adverse events, and 6.3% for thyroid dysfunction. The earliest case of onset was after the 1st course, and the latest cases occurred after the 66th course. By the sixth course, 69% of the irAEs occurred. The positive rates for anti-thyroid peroxidase and anti-thyroglobulin antibodies were higher in the irAE group compared to the non-irAE group. CONCLUSIONS: Our findings suggest a high probability of irAEs occurring early in ICI treatment, with a diverse range of symptoms. This underscores the need for vigilant monitoring and tailored patient management during the initial courses of ICI therapy.

Characteristics of Patients With Inflammatory Bowel Disease Who Develop Bloodstream Infection.

Background: The causative microorganisms of bloodstream infections (BSIs) in patients with inflammatory bowel disease (IBD) and the clinical characteristics of these patients have not yet been fully identified. Therefore, this study investigated IBD patients who developed BSI to determine their clinical characteristics and identify the BSI-causing bacteria. Methods: The subjects were IBD patients who developed bacteremia between 2015 and 2019 at Fukuoka University Chikushi Hospital. The patients were divided into two groups according to IBD type (Crohn's disease (CD) or ulcerative colitis (UC)). The medical records of the patients were reviewed to determine their clinical backgrounds and identify the BSI-causing bacteria. Results: In total 95 patients, 68 CD and 27 UC patients were included in this study. The detection rates of Pseudomonas aeruginosa (P. aeruginosa) and Klebsiella pneumoniae (K. pneumoniae) were higher in the UC group than in the CD group (18.5% vs. 2.9%, P = 0.021; 11.1% vs. 0%, P = 0.019, respectively). Immunosuppressive drugs use was higher in the CD group than in the UC group (57.4% vs. 11.1%, P = 0.00003). Hospital stay length was longer in the UC group than in the CD group (15 vs. 9 days; P = 0.045). Conclusions: The causative bacteria of BSI and clinical backgrounds differed between patients with CD and UC. This study showed that P. aeruginosa and K. pneumoniae had higher abundance in UC patients at the onset of BSI. Furthermore, long-term hospitalized patients with UC required antimicrobial therapy against P. aeruginosa and K. pneumoniae.

Methicillin-resistant Staphylococcus aureus bloodstream infections in a Japanese University Hospital between 1987 and 2004.

Methicillin-resistant Staphylococcus aureus (MRSA) infections have been the most common cause of nosocomial infections in Japan, but their genetic characteristics related to bloodstream infections have not been well studied. The aim of this study was to investigate a comprehensive molecular characterization of MRSA blood isolates during the historical 18-year study period between 1987 and 2004 in a tertiary care university hospital. A total of 137 MRSA isolates recovered from the blood of inpatients at Fukuoka University Hospital were analyzed. Clinical information and antimicrobial susceptibility profiles were reviewed, and staphylococcal chromosomal cassette mec (SCCmec), accessory gene regulator (agr), and a battery of bacterial genes were tested by PCR-based assays. The relatedness of these isolates was determined by the repetitive sequence-based PCR (rep-PCR) and pulsed-field gel electrophoresis (PFGE). Although low numbers of agr type III/SCCmec type IV isolates circulated between 1987 and 1992, agr type II/SCCmec type II isolates started circulating in 1993 and were responsible for the increased MRSA isolates until 2004. The rep-PCR and PFGE identified 104 epidemic and 33 sporadic isolates. Among the 104 epidemic isolates, six major rep-PCR/PFGE types were identified, which occupied 67.3% of epidemic isolates. The SCCmec type II and agr type II isolates were observed in significantly higher proportion in epidemic isolates than in sporadic isolates (P = 0.0318, P = 0.0123, respectively). In contrast, SCCmec type IV strains were observed in significantly higher proportion in sporadic isolates than in epidemic isolates (P = 0.0494). Although isolates with sec were detected in higher rates in epidemic isolates (P = 0.0397), seh was detected in higher rates in sporadic isolates (P = 0.0350). Multivariate logistic regression analysis with forward stepping revealed that SCCmec type II was independently associated with epidemic isolates (P = 0.0067; odds ratio, 1.75; 95% confidence interval, 1.17-2.64). These data indicated that SCCmec type II MRSA isolates were responsible for the increased MRSA bloodstream infections for inpatients during the 18-year study period in the hospital.

Intracellular Survival of Biofilm-Forming MRSA OJ-1 by Escaping from the Lysosome and Autophagosome in J774A Cells Cultured in Overdosed Vancomycin.

We investigated the drug-resistant mechanisms of intracellular survival of methicillin-resistant S. aureus (MRSA). Our established MRSA clinical strain, OJ-1, with high biofilm-forming ability, and a macrophage cell line, J774A, were used. After ingestion of OJ-1 by J774A, the cells were incubated for ten days with vancomycin at doses 30 times higher than the minimum inhibitory concentration. The number of phagocytosed intracellular OJ-1 gradually decreased during the study but plateaued after day 7. In J774A cells with intracellular OJ-1, the expression of LysoTracker-positive lysosomes increased until day 5 and then declined from day 7. In contrast, LysoTracker-negative and OJ-1-retaining J774A cells became prominent from day 7, and intracellular OJ-1 also escaped from the autophagosome. Electron microscopy also demonstrated that OJ-1 escaped the phagosomes and was localized in the J774A cytoplasm. At the end of incubation, when vancomycin was withdrawn, OJ-1 started to grow vigorously. The present results indicate that intracellular phagocytosed biofilm-forming MRSA could survive for more than ten days by escaping the lysosomes and autophagosomes in macrophages. Intracellular MRSA may survive in macrophages, and accordingly, they could be resistant to antimicrobial drug treatments. However, the mechanisms their escape from the lysosomes are still unknown. Additional studies will be performed to clarify the lysosome-escaping mechanisms of biofilm-forming MRSA.

The Limited Effect of a History of COVID-19 on Antibody Titers and Adverse Reactions Following BNT162b2 Vaccination: A Single-Center Prospective Study.

Background and Objectives: The need for, and ideal frequency of, the vaccination against coronavirus disease 2019 (COVID-19) of previously infected individuals have not yet been sufficiently evaluated. The aim of this study was to examine the anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody status and adverse reactions after vaccination among medical staff with or without a history of COVID-19. Materials and Methods: A single-center prospective study was performed at Fukuoka University Chikushi Hospital. We investigated the presence of the anti-SARS-CoV-2 antibody titer among medical staff before and after mRNA vaccination with the BNT162b2. The levels of immunoglobulin G antibody were quantitatively measured at six points-before vaccination, after the first vaccination, at three points after the second vaccination, and finally, after the third vaccination-and the levels were then compared based on the COVID-19 infection history. Results: The previously infected (before the first vaccination) subjects (n = 17) showed a marked increase in antibody titers two weeks after the first vaccination and four weeks after the second vaccination. Although they were able to maintain a certain level of antibody titers until 30 weeks after the second vaccination, the titers fell in the same way as observed in the non-infected subjects. The subjects who did not receive the third vaccination due to adverse reactions to previous vaccines (n = 1) or who were positive for COVID-19 prior to the third vaccination (n = 2) were excluded from the subsequent analyses. Among non-infected subjects (n = 36), smokers had lower peak antibody titers than the others. The previously infected subjects had a significantly higher incidence of adverse reactions after the first vaccination but had a similar incidence of adverse reactions after the second and third vaccinations compared to the non-infected subjects. Conclusions: A history of COVID-19 may influence only the initial increase in anti-SARS-CoV-2 antibody titers and the occurrence of adverse reactions after the first vaccination.

Collagen-derived dipeptide Pro-Hyp administration accelerates muscle regenerative healing accompanied by less scarring after wounding on the abdominal wall in mice.

Collagens act as cellular scaffolds in extracellular matrixes, and their breakdown products may also have important biological functions. We hypothesize that collagen dipeptide Pro-Hyp induces favorable healing activities and examined the effects of Pro-Hyp administered via different routes on wound healing using our novel murine model, in which an advanced fibrosis-prone scar lesion was developed in the abdominal muscle wall under the skin. After excising a part of the abdominal wall, a free-drinking experiment was performed using solutions with casein (CS), high molecular weight collagen peptides (HP), and low molecular weight collagen peptides including Pro-Hyp and Hyp-Gly (LP), in addition to water (HO). On day 21 of the study, when compared to the HO and CS groups, muscle regeneration in the LP group was significantly advanced in the granulation tissue, which was associated with a decrease in fibrosis. To clarify the effects of Pro-Hyp, daily intraperitoneal administration of pure Pro-Hyp was performed. Pro-Hyp administration induced many myogenically differentiated cells, including myogenin-positive myoblasts and myoglobin-positive myocytes, to migrate in the granulation tissue, while scar tissue decreased. These results indicated that Pro-Hyp administration accelerates muscle regenerative healing accompanied by less scarring after wounding on the abdominal wall.

A novel mouse wound model for scar tissue formation in abdominal muscle wall.

Hypertrophic scars found on the human body rarely develop in experimental animals, possibly due to their looser skin structure. This makes it difficult to understand the genesis of scar lesions. Therefore, appropriate animal models are urgently needed. In this study, we established a novel experimental model of a scar-forming wound by resecting a small portion of the abdominal muscle wall on the lower center of the abdomen in C57BL/6N mice, which are exposed to contractive forces by the surrounding muscle tissue. As a low-tension control, a back skin excision model was used with a splint fixed onto the excised skin edge, and granulation tissue formed on the muscle fascia supported by the back skeleton. One week after the resection, initial healing reactions, such as fibroblast proliferation, occurred in both models. However, after 21 days, lesions with collagen-rich granulation tissues, which were also accompanied by multiple nodular/spherical-like structures, developed only in the abdominal wall model. These lesions were analogous to scar lesions in humans. Therefore, the animal model developed in this study is unique in that fibrous scar tissues form under physiological conditions without using any artificial factors and is valuable for studying the pathogenesis and preclinical treatment of scar lesions.