Tadashi Maezawa

Dr. Tadashi Maezawa


Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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20 October 2023 in Medicina
Verified
Journal Article
Open access
PDF file
MNMikiko Nishioka
Mikiko Nishioka
TMTadashi Maezawa
Tadashi Maezawa
HTHiroki Takeuchi
Hiroki Takeuchi
KHKatsuyuki Hagiwara
Katsuyuki Hagiwara
STSachiyo Tarui
Sachiyo Tarui
TITomoaki Ikeda
Tomoaki Ikeda
Background and Objectives: A relationship between endometrial polypectomy and in vitro fertilization (IVF) pregnancy outcomes has been reported; however, only a few studies have compared polyp removal techniques and pregnancy rates. We investigated whether different polypectomy techniques with endometrial curettage and hysteroscopic polypectomy for endometrial polyps affect subsequent pregnancy outcomes. Materials and Methods: Data from 434 patients who had undergone polypectomy for suspected endometrial polyps using transvaginal ultrasonography before embryo transfer in IVF at four institutions between January 2017 and December 2020 were retrospectively analyzed. Overall, there were 157 and 277 patients in the hysteroscopic (mean age: 35.0 years) and curettage (mean age: 37.3 years) groups, respectively. Single-blastocyst transfer cases were selected from both groups and age-matched to unify background factors. Results: In the single-blastocyst transfer cases, 148 (mean age: 35.0 years) and 196 (mean age: 35.9 years) were in the hysteroscopic and curettage groups, respectively, with the 148 cases matched by age. In these cases, the pregnancy rates for the first embryo transfer were 68.2% (odds ratio (OR): 2.14) and 51.4% (OR: 1.06) in the hysteroscopic and curettage groups, respectively; the resulting OR was 2.03. The pregnancy rates after up to the second transfer were 80.4% (OR: 4.10) and 68.2% (OR: 2.14) in the hysteroscopic and curettage groups, respectively, in which the OR was 1.91. The live birth rates were 66.2% (OR: 1.956) and 53.4% (OR: 1.15) in the hysteroscopic and curettage groups, respectively, in which the odds ratio was 1.71. These results show the effectiveness of hysteroscopic endometrial polypectomy compared to polypectomy with endometrial curettage. No significant difference was found regarding the miscarriage rates between the two groups. Conclusions: Hysteroscopic endometrial polypectomy resulted in a higher pregnancy rate in subsequent embryo transfer than polypectomy with endometrial curettage. Therefore, establishing a facility where polypectomy can be performed hysteroscopically is crucial.

1 January 2024 in Reproductive Medicine and Biology
Verified
Journal Article
Open access
HTHiroki Takeuchi
Hiroki Takeuchi
MMMidori Morishita
Midori Morishita
MUMidori Uemura
Midori Uemura
TMTadashi Maezawa
Tadashi Maezawa
TSTakashi Shibahara
Takashi Shibahara
TITomoaki Ikeda
Tomoaki Ikeda
Purpose: Recently, noninvasive preimplantation genetic testing for aneuploidy (niPGT‐A) using cell‐free deoxyribonucleic acid has been developed; however, there are few reports on this and the results are inconsistent. This study was conducted to optimize the cultural environment.Methods: We used 35 blastocysts that had been discarded after in‐vitro fertilization. The concordance rate of karyotype analysis results between whole embryos (WEs), spent culture mediums (SCMs), and trophectoderms after 8, 16, and 24 h of culture was examined. Next, zona pellucida (ZP)‐free blastocysts and then early blastocysts were cultured for 24 h each.Results: Regarding the optimal culture times, the concordance rate between WEs and SCMs was 20%, 60%, and 100% at 8, 16, and 24 h, respectively. Significant differences were found between 8 and 24 h. The concordance rate with ZP cultures was 40.0%, and no significant differences were found. The concordance rate of early blastocysts thawed and cultured for 24 h was 40.0%, which was significantly lower than that of day 5 blastocysts.Conclusions: The optimal culture times for niPGT‐A were 24 h, and the concordance rate with free ZP was higher. The concordance rate for early blastocysts was low, suggesting that optimization of the conditions may be necessary.

1 April 2022 in Journal of Adolescent and Young Adult Oncology
Verified
Journal Article
Closed access
TMTadashi Maezawa
Tadashi Maezawa
NSNao Suzuki
Nao Suzuki
HTHiroki Takeuchi
Hiroki Takeuchi
CKChikako Kiyotani
Chikako Kiyotani
KAKeishiro Amano
Keishiro Amano
KMKimikazu Matsumoto
Kimikazu Matsumoto
Purpose: We conducted a questionnaire survey in 15 pediatric oncology hospitals in Japan to better understand the current status of fertility preservation in childhood and adolescents. Methods: The survey period was from September 2020 to December 2020. We mailed questionnaires to 64 departments involved in pediatric cancer treatments at the 15 hospitals. The primary outcomes were the timing of providing explanations on fertility preservation, presence of health care provider while providing explanations, cooperation between medical staff, and cooperation between hospitals. Results: The response rate was 100% (64/64). Regarding the time at which this information was provided, 79.6% of patients (43/54) received it before cancer treatment; 5.6% (3/54), after remission; and 14.8% (8/54), both time points. Nurses were mostly in attendance (70%) when oncologists provided information to patients. Nine (60%) hospitals did not have a reproductive department. Among these, 28.6% of the respondents referred patients to a reproductive facility that performed fertility preservation. Providing information about fertility preservation was challenging owing to the shortage of specific explanatory materials (35.1%) and the lack of cooperation between pediatric oncologists and reproductive endocrinologists (24.6%). Conclusion: Based on this survey, educational activities regarding fertility preservation centered on pediatric oncologists and nurses are needed. Furthermore, a system for providing explanatory materials for fertility preservation and encouraging cooperation at the physician and hospital levels is also needed (IRB No. H2020-111).

7 November 2023 in Cells
Verified
Journal Article
Open access
PDF file
RTRyota Tachibana
Ryota Tachibana
HTHiroki Takeuchi
Hiroki Takeuchi
KYKento Yoshikawa-Terada
Kento Yoshikawa-Terada
TMTadashi Maezawa
Tadashi Maezawa
MNMikiko Nishioka
Mikiko Nishioka
TITomoaki Ikeda
Tomoaki Ikeda
Sperm DNA fragmentation (SDF) that occurs during the freezing–thawing of sperm may negatively impact the treatment outcomes of assisted reproductive technologies (ART). In a previous study, we developed a human sperm cryopreservation reagent containing carboxylated poly-L-lysine (CPLL) that reduced SDF after freeze-thawing compared with clinically popular cryopreservation reagents containing human serum albumin. However, it is unclear whether CPLL reduces SDF, as it differed from the constituents of the commercial cryopreservation reagents used for comparison. Therefore, here, we examined whether CPLL reduces the SDF of human sperm and evaluated reactive oxygen species (ROS) levels and lipid peroxidation (LPO), which are the causes of SDF; mitochondrial injury, ROS production; and impaired sperm motility. Furthermore, optimal antioxidants and their concentrations that could further enhance the reduction in SDF were determined for future clinical application in ART and underwent the same functional evaluations. CPLL can reduce SDF via inhibition of intracytoplasmic ROS and LPO. Furthermore, the addition of 0.1 mM resveratrol avoided the enhancement of SDF, which potentially affects mitochondrial and cytoplasmic ROS and LPO. This novel human sperm cryopreservation reagent containing CPLL and resveratrol has the potential to improve treatment outcomes in ART using frozen sperm.

1 June 2023 in Journal of Adolescent and Young Adult Oncology
Verified
Journal Article
Closed access
TMTadashi Maezawa
Tadashi Maezawa
STSeido Takae
Seido Takae
HTHiroki Takeuchi
Hiroki Takeuchi
MTMotoki Takenaka
Motoki Takenaka
Kuniaki OtaKuniaki Ota
Kuniaki Ota
NSNao Suzuki
Nao Suzuki
Purpose: The demand for fertility preservation continues to grow as cancer treatment outcomes improve. The specimen storage period is longer for fertility preservation than for conventional fertility treatment; therefore, a robust management system for stored specimens is required. We conducted the first national survey in Japan on the management of cryopreserved specimens in fertility preservation facilities. Methods: Questionnaires were mailed to 130 fertility preservation facilities. Primary outcomes included the official position of the storage manager, support system in case of facility closure, disaster countermeasures, management and operating system for liquid nitrogen storage containers, preservation costs, and method to confirm the intention to continue storage. Results: The response rate was 63.8%. The facility director most commonly functioned as the storage manager (59.0%). In case of facility closure, 20.5% had an approved transfer site; 59.0% had not made any decisions. In the management of liquid nitrogen containers, 83.1% regularly replenished the liquid nitrogen, 65.1% regularly checked the amount, and 16.9% had alarm monitoring systems. Regarding disaster countermeasures, 70.9% had taken measures to protect specimens. Conclusion: This survey revealed issues such as disparities among facilities regarding long-term specimen storage systems. Accordingly, management standards for fertility preservation facilities should be established.

1 February 2024 in Journal of Adolescent and Young Adult Oncology
Verified
Journal Article
Closed access
TMTadashi Maezawa
Tadashi Maezawa
NSNao Suzuki
Nao Suzuki
HTHiroki Takeuchi
Hiroki Takeuchi
MNMikiko Nishioka
Mikiko Nishioka
MHMoe Hidaka
Moe Hidaka
KMKimikazu Matsumoto
Kimikazu Matsumoto
Purpose : Although fertility preservation for pediatric cancer patients is becoming more widespread in Japan, some facilities do not provide sufficient information regarding fertility. This study aimed to elucidate the problems pertaining to the lack of information about fertility among patients. Methods: Based on a 2020 survey, seminars addressing fertility preservation were held from the Designated Pediatric Cancer Care Hospitals in each of the seven blocks in Japan to their partner hospital (pediatric cancer hospitals). The seminar consisted of lectures and group discussions, and a questionnaire was also administered after each seminar. Results: In the group discussions, a lack of explanations to patients and explanatory materials for children were cited as issues by many facilities. The survey results revealed a lack of material explaining fertility preservation and a lack of knowledge among health care providers. There were also many requests to use the patient explanation videos presented at the seminar. Conclusion: The results indicate that further education for health care providers by seminar and other sources and enhancement of explanatory materials are important for fertility preservation in pediatric cancer hospitals in Japan.