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This study aimed to evaluate the antibacterial effects of a newly designed preservative-free multi-dose eye dropper that addresses various shortcomings found in conventional models. To thoroughly assess its performance, we compared bacterial contamination and filtration effects over time among three types of droppers: commercially available multi-dose droppers, conventional preservative-free droppers, and the newly designed preservative-free dropper utilizing air pressure differentials. The bacterial strains used to evaluate contamination included Staphylococcus aureus, Bacillus subtilis, and Aspergillus brasiliensis, with turbidity levels measured according to the McFarland Standards to ensure accuracy. In typical multi-dose eye droppers, bacterial contamination tended to increase significantly with extended usage periods, leading to potential health risks. However, in the preservative-free eye dropper using air pressure differentials, no bacterial growth was observed throughout the entire experimental period. In both forward and reverse filtration tests, the new preservative-free eye dropper successfully prevented bacteria from entering the vial and from being released to the outside through the dropper tip. Overall, this preservative-free reusable eye dropper, which relies on air pressure differentials, offers a safe, effective, and hygienic option for administering eye drops, while minimizing the side effects associated with preservatives and maintaining the sterility of the solution over time.

The development of new treatment agents in recent decades has significantly improved the survival of patients with multiple myeloma (MM). Nonetheless, MM remains an incurable disease; therefore, novel combination therapies are required. Natural killer (NK) cells are one of the safest immunotherapeutic options. In this study, we found that the anti-myeloma activity of expanded NK cells (eNKs) was improved by daratumumab, lenalidomide, and dexamethasone (DRd) in an MM xenograft mouse model. NK cells expanded from peripheral blood mononuclear cells collected from MM patients were highly cytotoxic against DRd pretreated tumor cells in vitro. To mimic the clinical protocol, a human MM xenograft model was developed using human RPMI8226-RFP-FLuc cells in NOD/SCID IL-2Rγnull (NSG) mice. MM bearing mice were randomly divided into six groups: no treatment, eNK, Rd, Rd + eNKs, DRd, and DRd + eNKs. DRd significantly enhanced the cytotoxicity of eNKs by upregulating NK cell activation ligands and effector function. DRd in combination with eNKs significantly reduced the serum M-protein level and prolonged mouse survival. In addition, DRd significantly increased the persistence of eNK and homing to MM sites. These results show that the anti-myeloma activity of ex vivo-expanded and activated NK cells is augmented by the immunomodulatory effect of DRd in MM-bearing mice, suggesting the therapeutic potential of this combination for MM patients.

Objectives This study aimed to evaluate the prognostic significance of the revised European LeukemiaNet (ELN)−2022 risk stratification model for 123 elderly acute myeloid leukemia (AML) patients treated with decitabine chemotherapy.Results Based on the ELN-2022 risk stratification, 15 (12.2%), 51 (41.5%), and 57 (46.3%) patients were classified as having favorable, intermediate, and high-risk AML, respectively. In comparison with the ELN-2017 risk stratification, the ELN-2022 risk stratification re-assigned 26 (21.1%) and three (2.4%) patients to the adverse and favorable risk groups, respectively. Survival analysis revealed distinctive overall survival (OS) outcomes among the ELN-2022 risk groups (6-month OS rate: 73.3%, 52.9%, and 47.7% for favorable, intermediate, and adverse risk, respectively; P = 0.101), with a parallel trend observed in the event-free survival (EFS) (6-month EFS rate: 73.3%, 52.9%, and 45.6% for favorable, intermediate, and adverse risk, respectively; P = 0.049). Notably, both OS and EFS in the favorable risk group were significantly superior in comparison to that of the adverse risk group (OS: P = 0.040, EFS: P = 0.030). Although the ELN-2022 C-index (0.559) was greater than the ELN-2017 C-index (0.539), the result was not statistically significant (P = 0.059). Based on the event net reclassification index, we consistently observed significant improvements in the ELN-2022 risk stratification for overall survival (0.21 at 6 months).Conclusion In conclusion, the revised ELN-2022 risk stratification model may have improved the risk classification of elderly AML patients treated with hypomethylating agents compared to the ELN-2017 risk stratification model.

Background/Aims Since the coronavirus disease 2019 (COVID-19) outbreak, hospitals have implemented infection control measures to minimize the spread of the virus within facilities. This study aimed to investigate the impact of COVID-19 on the incidence of healthcare-associated infections (HCAIs) and common respiratory virus (cRV) infections in hematology units. Methods This retrospective study included all patients hospitalized in Catholic Hematology Hospital between 2019 and 2020. Patients infected with vancomycin-resistant Enterococci (VRE), carbapenemase-producing Enterobacterales (CPE), Clostridium difficile infection (CDI), and cRV were analyzed. The incidence rate ratio (IRR) methods and interrupted time series analyses were performed to compare the incidence rates before and after the pandemic. Results The incidence rates of CPE and VRE did not differ between the two periods. However, the incidence of CDI increased significantly (IRR: 1.41 [p = 0.002]) after the COVID-19 pandemic. The incidence of cRV infection decreased by 76% after the COVID-19 outbreak (IRR: 0.240 [p < 0.001]). The incidence of adenovirus, parainfluenza virus, and rhinovirus infection significantly decreased in the COVID-19 period (IRRs: 0.087 [p = 0.003], 0.031 [p < 0.001], and 0.149 [p < 0.001], respectively). Conclusions The implementation of COVID-19 infection control measures reduced the incidence of cRV infection. However, CDI increased significantly and incidence rates of CPE and VRE remained unchanged in hematological patients after the pandemic. Infection control measures suitable for each type of HCAI, such as stringent hand washing for CDI and enough isolation capacities, should be implemented and maintained in future pandemics, especially in immunocompromised patients.

Purpose: Centered on the framework of global citizenship education (GCED), an after-school music program was developed for middle school students in Korea. The program aims to introduce multicultural topics to improve intercultural understanding and promote multicultural sensitivity for community relations development in response to rapid demographics changes in Korea. A total of 143 students have participated in the twenty-nine week (29) pilot program. The program included orchestra and ensemble performances, learning ethnic songs and cultural backgrounds, and related educational activities. Research method: Methodological triangulation was used to evaluate the significance of the program. Program surveys, formative and summative evaluations, and interviews were used as the assessment instruments to measure the program outcome. Results: A music program based on the framework of GCED provided a good platform for gaining knowledge on teaching civic and multicultural education. The program displayed a measurable gain in students' positive attitudes towards community relations.

Aim: To describe the development of an intervention-specific fidelity measure and its utilization and to determine whether the newly developed Sitting Together and Reaching to Play (START-Play) intervention was implemented as intended. Also, to quantify differences between START-Play and usual early intervention (uEI) services. Method: A fidelity measure for the START-Play intervention was developed for children with neuromotor disorders by: (1) identifying key intervention components; (2) establishing a measurement coding system; and (3) testing the reliability of instrument scores. After establishing acceptable interrater reliability, 103 intervention videos from the START-Play randomized controlled trial were coded and compared between the START-Play and uEI groups to measure five dimensions of START-Play fidelity, including adherence, dosage, quality of intervention, participant responsiveness, and program differentiation. Results: Fifteen fidelity variables out of 17 had good to excellent interrater reliability evidence with intraclass correlation coefficients (ICCs) ranging from 0.77 to 0.95. The START-Play therapists met the criteria for acceptable fidelity of the intervention (rates of START-Play key component use [greater than or equal to]0.8; quality ratings [greater than or equal to]3 [on a scale of 1-4]). The START-Play and uEI groups differed significantly in rates of START-Play key component use and quality ratings. Interpretation: The START-Play fidelity measure successfully quantified key components of the START-Play intervention, serving to differentiate START-Play from uEI.

Background/Aims The prognostic significance of 18F-fluorodeoxyglucose (FDG)-positron emission tomography-computed tomography (PET/CT) in peripheral T-cell lymphomas (PTCLs) are controversial. We explored the prognostic impact of sequential 18F-FDG PET/CT during frontline chemotherapy of patients with PTCLs. Methods In total, 143 patients with newly diagnosed PTCLs were included. Sequential 18F-FDG PET/CTs were performed at the time of diagnosis, during chemotherapy, and at the end of chemotherapy. The baseline total metabolic tumor volume (TMTV) was calculated using the the standard uptake value with a threshold method of 2.5. Results A baseline TMTV of 457.0 cm3 was used to categorize patients into high and low TMTV groups. Patients with a high TMTV had shorter progression-free survival (PFS) and overall survival (OS) than those with a low TMTV (PFS, 9.8 vs. 26.5 mo, p = 0.043; OS, 18.9 vs. 71.2 mo, p = 0.004). The interim 18F-FDG PET/CT response score was recorded as 1, 2–3, and 4–5 according to the Deauville criteria. The PFS and OS showed significant differences according to the interim 18F-FDG PET/CT response score (PFS, 120.7 vs. 34.1 vs. 5.1 mo, p < 0.001; OS, not reached vs. 61.1 mo vs. 12.1 mo, p < 0.001). Conclusions The interim PET/CT response based on visual assessment predicts disease progression and survival outcome in PTCLs. A high baseline TMTV is associated with a poor response to anthracycline-based chemotherapy in PTCLs. However, TMTV was not an independent predictor for PFS in the multivariate analysis.

Dendritic cells (DCs) are the most potent antigen-presenting cells, and have thus been used in clinical cancer vaccines. However, the effects of DC vaccines are still limited, leading researchers to explore novel ways to make them effective. In this study, we investigated whether human monocyte-derived DCs generated via the addition of interleukin 15 (IL-15) had a higher capacity to induce antigen-specific T cells compared to conventional DCs. We isolated CD14+ monocytes from peripheral blood from multiple myeloma (MM) patients, and induced immature DCs with granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4 in the presence or absence of IL-15 for 4-6 days. Then we generated mature DCs (mDCs) with lipopolysaccharide for another 2 days [IL-15 mDCs (6 days), IL-15 mDCs (8 days), and conventional mDCs (8 days)]. IL-15 mDCs (6 days) showed higher expression of MHC I and II, CD40, CD86, and CCR7, and the secretion of IFN-γ was significantly higher compared to conventional mDCs. IL-15 mDCs (6 days) showed superior polarization of naïve T cells toward Th1 cells and a higher proportion of activated T cells, cytokine-induced killer (CIK) cells, and natural killer (NK) cells for inducing strong cytotoxicity against myeloma cells, and lower proportion of regulatory T cells compared to conventional mDCs. These data imply that novel multipotent mDCs generated by the addition of IL-15, which can be cultivated in 6 days, resulted in outstanding activation of T cells, CIK cells and NK cells, and may facilitate cellular immunotherapy for cancer patients.

Objective: Our objective was to evaluate the efficacy of the Sitting Together and Reaching to Play (START-Play) intervention in young infants with neuromotor disorders. Method: This randomized controlled trial compared usual care-early intervention (UC-EI) with START-Play plus UC-EI. Analyses included 112 infants with motor delay (55 UC-EI, 57 START-Play) recruited at 7 to 16 months of age across 5 sites. START-Play included twice-weekly home visits with the infant and caregiver for 12 weeks provided by physical therapists trained in the START-Play intervention; UC-EI was not disrupted. Outcome measures were the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley); the Gross Motor Function Measure; reaching frequency; and the Assessment of Problem Solving in Play (APSP). Comparisons for the full group as well as separate comparisons for infants with mild motor delay and infants with significant motor delay were done. Piecewise linear mixed modeling estimated short- and long-term effects. Results: For infants with significant motor delay, positive effects of START-Play were observed at 3 months for Bayley cognition Bayley fine motor, and APSP and at 12 months for Bayley fine motor and reaching frequency outcomes. For infants with mild motor delay, positive effects of START-Play for the Bayley receptive communication outcome were found. For the UC-EI group, the only difference between groups was a positive effect for the APSP outcome, observed at 3 months. Conclusions: START-Play may advance reaching, problem-solving, cognitive, and fine motor skills for young infants with significant motor delay over UC-EI in the short term. START-Play in addition to UC-EI may not improve motor/cognitive outcomes for infants with milder motor delays over and above usual care. Impact: Concepts of embodied cognition, applied to early intervention in the START-Play intervention, may serve to advance cognition and motor skills in young infants with significant motor delays over usual care early intervention. Lay Summary: If you have a young infant with significant delays in motor skills, your physical therapist can work with you to develop play opportunities to enhance your child's problem-solving, such as that used in the START-Play intervention, in addition to usual care in order to help your child advance cognitive and motor skills.

Considering the significance and impact of COVID-19 global pandemic to the global economy and education, ethics should be highlighted as a fundamental facet of technology related disciplines, and professional responsibilities need to be taught in higher education. Introducing ethics to undergraduate engineering students is critical in order to develop professionals who will make important and consequential decisions and perform the best practices in the technology field. Therefore, undergraduate institutions should provide opportunities to students to acquire knowledge and skills about ethical principles that affect engineering practices. This essay addresses the history of engineering ethics education and some challenges in higher education institutions in the United States.

As a result of the sudden onset of the COVID-19 pandemic, engineering curriculums that were taught in-person for decades were forcibly transitioned into a remote-learning environment in such a short time that instructors and students alike could not adequately consider how to replicate the efficacy and efficiency of in-person learning to the remote learning environment. In this essay, the problem of effective replication is studied from the perspective of emotional experiences that lead to effective learning. Through this review, the authors hope to enlighten instructors and students about simple and effective practices that can be implemented in this harsh environment and to mitigate the effect that COVID-19 will inevitably have on the effectiveness and enrollment of engineering undergraduate curriculums.

Abstract The study aimed to identify critical factors associated with the surgical stability of pogonion (Pog) by applying machine learning (ML) to predict relapse following two-jaw orthognathic surgery (2 J-OGJ). The sample set comprised 227 patients (110 males and 117 females, 207 training and 20 test sets). Using lateral cephalograms taken at the initial evaluation (T0), pretreatment (T1), after (T2) 2 J-OGS, and post treatment (T3), 55 linear and angular skeletal and dental surgical movements (T2-T1) were measured. Six ML modes were utilized, including classification and regression trees (CART), conditional inference tree (CTREE), and random forest (RF). The training samples were classified into three groups; highly significant (HS) (≥ 4), significant (S) (≥ 2 and

Purpose: We compared semen quality and sperm DNA fragmentation in cancer patients who underwent sperm banking and controls who underwent sperm cryopreservation for assisted reproductive technology (ART). Materials and Methods: A total of 132 men, 65 cancer patients and 67 controls, were prospectively enrolled and performed sperm cryopreservation for fertility preservation from May 2019 to February 2021. Sperm quality was determined by measuring semen volume, sperm concentration, sperm motility, and sperm DNA fragmentation index (DFI). Sperm quality and sperm DFI were compared in cancer patients and controls. Results: The major cancers of the 65 cancer patients were leukemia (26.2%), testicular cancer (23.1%), and lymphoma (20.0%). Sperm concentration, sperm total motility, and sperm progressive motility were significantly lower in cancer patients than in controls. Sperm DFI was significantly higher in cancer patients than in controls (24.32%±15.69% vs. 19.11%±11.63%; p=0.033). After excluding 8 cancer patients who received chemotherapy before sperm banking, sperm concentration, sperm total motility, and sperm progressive motility were significantly lower in cancer patients than in controls, but there was no significant difference in sperm DFI for cancer patients and controls (23.14%±12.79% vs. 19.11%±11.63%; p=0.069). Conclusions: Sperm quality was lower in cancer patients than in controls. There was no difference in the sperm DFI of cancer patients prior to chemotherapy and men presenting for sperm cryopreservation for ART. We recommend that all men who are planning cancer therapy should be offered sperm banking prior to gonadotoxic chemotherapy as a standard of fertility preservation.

Abstract Arachidonic and adrenic acids in the membrane play key roles in ferroptosis. Here, we reveal that lipoprotein-associated phospholipase A2 (Lp-PLA2) controls intracellular phospholipid metabolism and contributes to ferroptosis resistance. A metabolic drug screen reveals that darapladib, an inhibitor of Lp-PLA2, synergistically induces ferroptosis in the presence of GPX4 inhibitors. We show that darapladib is able to enhance ferroptosis under lipoprotein-deficient or serum-free conditions. Furthermore, we find that Lp-PLA2 is located in the membrane and cytoplasm and suppresses ferroptosis, suggesting a critical role for intracellular Lp-PLA2. Lipidomic analyses show that darapladib treatment or deletion of PLA2G7, which encodes Lp-PLA2, generally enriches phosphatidylethanolamine species and reduces lysophosphatidylethanolamine species. Moreover, combination treatment of darapladib with the GPX4 inhibitor PACMA31 efficiently inhibits tumour growth in a xenograft model. Our study suggests that inhibition of Lp-PLA2 is a potential therapeutic strategy to enhance ferroptosis in cancer treatment.

Background/Aims We evaluated the role of next-generation sequencing (NGS)-based disease monitoring for elderly patients diagnosed with acute myeloid leukemia (AML) who received decitabine therapy. Methods A total of 123 patients aged > 65 years with AML who received decitabine were eligible. We analyzed the dynamics of variant allele frequency (VAF) in 49 available follow-up samples after the fourth cycle of decitabine. The 58.6% VAF clearance (Δ, [VAF at diagnosis – VAF at follow-up] × 100 / VAF at diagnosis) was the optimal cut-off for predicting overall survival (OS). Results The overall response rate was 34.1% (eight patients with complete remission [CR], six of CR with incomplete hematologic recovery, 22 with partial responses, and six with morphologic leukemia-free status). Responders (n = 42) had significantly better OS compared with non-responders (n = 42) (median, 15.3 months vs. 6.5 months; p < 0.001). Of the 49 patients available for follow-up targeted NGS analysis, 44 had trackable gene mutations. The median OS of patients with ΔVAF ≥ 58.6% (n=24) was significantly better than that of patients with ΔVAF < 58.6% (n = 19) (20.5 months vs. 9.8 months, p = 0.010). Moreover, responders with ΔVAF ≥ 58.6% (n = 20) had a significantly longer median OS compared with responders with VAF < 58.6% (n = 11) (22.5 months vs. 9.8 months, p = 0.004). Conclusions This study suggested that combining ΔVAF ≥ 58.6%, a molecular response, with morphologic and hematologic responses can more accurately predict OS in elderly AML patients after decitabine therapy.

Abstract Bersiporocin, a novel first‐in‐class prolyl‐tRNA synthetase (PRS) inhibitor currently under clinical development, was shown to exert an antifibrotic effect through the downregulation of collagen synthesis in various pulmonary fibrosis models. The aim of this first‐in‐human, randomized, double‐blind, placebo‐controlled, single‐ and multiple‐dose, dose‐escalation study was to evaluate the safety, tolerability, pharmacokinetic (PK) and pharmacodynamic (PD) characteristics of bersiporocin in healthy adults. A total of 40 and 32 subjects were included in a single‐ (SAD) and multiple‐ascending dose (MAD) study, respectively. No severe or serious adverse events were observed after a single oral dose up to 600 mg and multiple oral doses up to 200 mg twice daily for 14 days. The most common treatment‐emergent adverse events were gastrointestinal adverse events. To improve the tolerability, initial bersiporocin solution was changed to the enteric‐coated formulation. Afterward, the enteric‐coated tablet was used in the last cohort of SAD and in the MAD study. Bersiporocin showed dose‐proportional PK characteristics after a single dose up to 600 mg and multiple doses up to 200 mg. Upon reviewing the safety and PK data, the final SAD cohort (800 mg enteric‐coated tablet) was canceled by the Safety Review Committee. The levels of pro‐peptide of type 3 procollagen were lower after treatment with bersiporocin than after the placebo in the MAD study, whereas no significant change was observed in other idiopathic pulmonary fibrosis (IPF) biomarkers. In conclusion, the safety, PK, and PD profile of bersiporocin supported its further investigation in patients with IPF.

An online survey was conducted to explore how Instagram users’ selfie-posting behavior affects their self-esteem and body dissatisfaction. Female college students from South Korea (N = 321) participated in the survey. Results showed that Instagram users’ selfie-posting was positively related to their self-esteem. Moreover, Instagram users’ self-esteem mediated the relationship between their selfie-posting behavior and body dissatisfaction. Findings showed that Instagram users’ selfie-posting behavior may positively influence their self-esteem, which may consequently contribute to reducing their body dissatisfaction. Such an indirect effect of selfie-posting was moderated by Instagram users’ levels of the need for popularity. The indirect influence of selfie-posting on body dissatisfaction through self-esteem was only significant among those with low or moderate levels of the need for popularity. This suggests that those with lower levels of the need for popularity can benefit more from posting their selfies. These findings advance the emerging literature on the effects of selfie-posting by providing a moderated mediation model of selfie-posting and body image concerns.

IntroductionDespite the current effective treatments for acute promyelocytic leukemia (APL), early mortality (EM), defined as death within 30 days of presentation, is a major hurdle to long-term survival.MethodsWe performed a multicenter retrospective study to evaluate the incidence and clinical characteristics of EM in patients with newly diagnosed APL and to develop a risk stratification model to predict EM.ResultsWe identified 313 eligible patients diagnosed between 2000 and 2021 from five academic hospitals. The median age was 50 years (range 19-94), and 250 (79.9%) patients were 24 hours of presentation (HR, 2.95). Based on these factors, patients were stratified into three categories with a significantly increasing risk of EM: 4.1% for low risk (54.3%; no risk factors; HR 1), 18.5% for intermediate risk (34.5%; 1 factor; HR 4.81), and 40.5% for high risk (11.2%; 2-3 factors; HR 13.16).DiscussionThe risk of EM is still not negligible in this era of ATRA-based therapies. Our risk model serves as a clinically useful tool to identify high-risk patients for EM who may be candidates for novel treatments and aggressive supportive strategies.

Purpose: This study examines object permanence development in infants with motor delays (MD) compared with infants with typical development (TD) and in relation to sitting skill. Methods: Fifty-six infants with MD (mean age = 10 months) and 36 with TD (mean age = 5.7 months) were assessed at baseline and then at 1.5, 3, and 6 months postbaseline. A scale was developed to measure object permanence (Object Permanence Scale [OPS]), and the Gross Motor Function Measure sitting subsection (GMFM-SS), and the Bayley Scales of Infant and Toddler Development, 3rd Edition (Bayley-III) were administered. Results: Interrater reliability of the OPS was excellent and correlation between the OPS and Bayley-III cognitive scores was moderately positive. Compared with TD, infants with MD were delayed in development of object permanence but demonstrated increased understanding over time and as sitting skills improved. Conclusion: In children with MD, object permanence, as quantified by the OPS, emerges in conjunction with sitting skill.

Purpose: This case series documents developmental changes over time and in response to a novel intervention, Sitting Together and Reaching to Play (START-Play), in children with early-life seizures. Methods: Thirteen children with early-life seizures were included from a subset of participants in the START-Play multisite, randomized controlled trial. Seven received 3 months of twice weekly START-Play intervention; 6 continued with usual care early intervention. Bayley Scales of Infant Development-III (Cognitive Composite), Gross Motor Function Measure-66 Item Set, Assessment of Problem-Solving in Play, and reaching assessments were administered at baseline, 3, 6, and 12 months postbaseline. Change scores are reported at 3 and 12 months postbaseline. Results: Over time, plateau or decline was noted in standardized cognition measures; motor development improved or was stable. Children receiving START-Play showed positive trends in problem-solving (71.4%) and reaching behaviors (57.2%). Conclusions: Interventions such as START-Play that combine motor and cognitive constructs may benefit children with early-life seizures.

First-in-class membrane stabilizer Poloxamer 188 (P188) has been shown to confer membrane protection in an extensive range of clinical conditions; however, elements of the systemic distribution and localization of P188 at the organ, tissue, and muscle fiber levels in vivo have not yet been elucidated. Here we used non-invasive fluorescence imaging to directly visualize and track the distribution and localization of P188 in vivo. The results demonstrated that the Alx647 probe did not alter the fundamental properties of P188 to protect biological membranes. Distribution kinetics in mdx mice demonstrated that Alx647 did not interface with muscle membranes and had fast clearance kinetics. In contrast, the distribution kinetics for P188-Alx647 was significantly slower, indicating a dramatic depot and retention effect of P188. Results further demonstrated the significant retention of P188-Alx647 in the skeletal muscle of mdx mice, showing a significant genotype effect with a higher fluorescence signal in the mdx muscles over BL10 mice. High-resolution optical imaging provided direct evidence of P188 surrounding the sarcolemma of skeletal and cardiac muscle cells. Taken together, these findings provide direct evidence of muscle-disease-dependent molecular homing and retention of synthetic copolymers in striated muscles thereby facilitating advanced studies of copolymer-membrane association in health and disease.

Purpose: There have been concerns regarding potential effects of older paternal age on male reproductive function. However, currently available data on this topic are insufficient and controversy exists. We analyzed semen characteristics and reproductive hormones in young men and middle-aged men to investigate the effect of age on male reproductive function. Materials and Methods: This study examined healthy males of reproductive age who visited a single infertility center from January 2016 to July 2021. The young group consisted of men who were less than 35 years-old, and the middle-age group consisted of men who were more than 45 years-old. Results: The two groups had no significant differences in sperm concentration ([89.9±59.4]×106/mL vs. [104.4±82.1]×106/mL, p=0.108) or sperm morphology (normal forms: 3.6%±1.5% vs. 3.4%±1.6%, p=0.131). However, the middle-age group had a smaller semen volume (3.2±1.5 mL vs. 2.5±1.4 mL, p