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1.
IJU Case Rep ; 7(5): 364-367, 2024 Sep.
Article in English | MEDLINE | ID: mdl-39224676

ABSTRACT

Introduction: Transverse testicular ectopia is a rare anomaly in which both testes descend toward the same side of the hemiscrotum. Case presentation: A 35-year-old man presented with right inguinal enlargement. Computed tomography showed a normal testis in the right hemiscrotum and a 58 mm heterogeneous mass in the right inguinal area. No testis was observed in the left hemiscrotum. The vascular structures extended from the right inguinal mass to the left renal vein. Consequently, the left testicular tumor was diagnosed as transverse testicular ectopia, and a left orchiectomy was performed. The histological diagnosis was seminoma stage pT2. Furthermore, left para-aortic lymph node metastasis developed 10 months postoperatively. A complete response was obtained after systemic chemotherapy. Conclusion: Awareness of seminomas in transverse testicular ectopia could facilitate appropriate diagnosis and treatment. Furthermore, the location of the lymph node metastasis indicated that the ectopic testis could have originated from the left side.

2.
Reprod Med Biol ; 23(1): e12608, 2024.
Article in English | MEDLINE | ID: mdl-39318590

ABSTRACT

Case: A 40-year-old Japanese man with nonobstructive azoospermia (NOA) was found to carry rare variants in KCTD19, a newly identified causative gene for spermatogenic failure. This patient was identified through mutation screening of KCTD19 in 97 men with etiology-unknown isolated NOA. Outcome: The patient had two heterozygous variants in KCTD19 that affect consensus sequences of splice-donor sites [c.300+2T>A and c.2667C>T (p.E889E)]. Both variants were predicted to cause exon skipping. Long-read sequencing confirmed the compound heterozygosity of the variants. The patient exhibited small testes and a mildly elevated level of follicle-stimulating hormone but no other phenotypic abnormalities. Testicular histology showed borderline findings between spermatocyte maturation arrest and severe hypospermatogenesis. Conclusion: These results provide evidence that biallelic loss-of-function variants of KCTD19 represent rare causes of isolated NOA.

3.
J Mech Behav Biomed Mater ; 159: 106647, 2024 Nov.
Article in English | MEDLINE | ID: mdl-39178822

ABSTRACT

For designing trabecular (Tb) bone substitutes suffering from osteoporosis, finite element model (FEM) simulations were conducted on honeycombs (HCs) of 8 × 8 × 1 (2D) and 8 × 8 × 8 (3D) assemblies of cube cellular units consisting of 0.9 mm long Nylon® 66 (PA, Young's modulus E: 2.83 GPa) and polyethylene (PE, E: 1.1 GPa) right square prisms. Osteoporotic damage to the Tb bone was simulated by removing the inner vertical struts (pillars; the number of removed pillars: Δn ≤ 300) and by thinning the strut (thickness, d: 0.4-0.1 mm), while the six facade lattices were kept flawless. Uniform and uniaxial compressive loads on the HCs induced elastic deformation of the struts. The pillars held almost all the load, while the horizontal struts (beams) shared little. E for PA 3D HCs of all d smoothly decreased with Δn. PA 3D HCs of 0.2 mm struts deserved to be the substitutes for Tb bone, while PE 3D HCs of 0.05 mm struts were only for the Tb bone of the poorest bone quality. For the PA 3D HCs, the maximum von Mises stress (σM) first rapidly increased with Δn and showed a break at Δñ50, then gradually approached the yield stress of PA (50 MPa). Moreover, small portions of the stress were transferred from the façade pillars to the adjacent inner beams, especially those near the lost-pillar sites, denoted as X defects. The floor beams of thinner struts associated with the X-defects were lifted, and similar lifting effects in smaller amounts were propagated to the other floors. The 3DHCs of the thicker struts showed no such flexural deformations. The concept of force percolation through the remaining struts was proposed to interpret those mechanical behaviors of the HCs.


Subject(s)
Bone Substitutes , Finite Element Analysis , Materials Testing , Stress, Mechanical , Cancellous Bone
4.
Cytogenet Genome Res ; : 1-6, 2024 Jul 29.
Article in English | MEDLINE | ID: mdl-39074465

ABSTRACT

INTRODUCTION: Isodicentric Y chromosomes are relatively common structural variants of the human genome. The underlying mechanism of isodicentric Y chromosomes with short arm breakpoints [idic(Yq)] remains to be clarified. CASE PRESENTATION: We encountered a Japanese man with azoospermia and mild short stature. G-banding and array-based comparative genomic hybridization indicated that his karyotype was 45,X/46,X,idic(Y)(qter→p11.32::p11.32→qter) with a ∼1.8 Mb terminal deletion. Whole-genome sequencing suggested that the Y chromosome had four breakpoints in a ∼7 kb region of the pseudoautosomal region 1 (PAR1). CONCLUSION: This case was assumed to have an idic(Yq) resulting from multiple DNA double-strand breaks in PAR1. This rearrangement may have been facilitated by the PAR1-specific chromatin architecture. The clinical features of the patient can be ascribed to SHOX haploinsufficiency and the presence of a 45,X cell line, although copy-number gains of some Yq genes and the size reduction of PAR1 may also contribute to his spermatogenic failure.

5.
Adv Healthc Mater ; 13(22): e2304668, 2024 Sep.
Article in English | MEDLINE | ID: mdl-38925602

ABSTRACT

Healing bone erosions in rheumatoid arthritis (RA) remains greatly challenging via biomaterial strategies. Given the unsuccessful innate bone erosion healing due to an inflammatory disorder, over-activated osteoclasts, and impaired osteoblasts differentiation, RA pathogenesis-guided engineering of an innovative hydrogel platform is needed for remodeling osteoimmune and osteogenic microenvironment of bone erosion healing. Herein, in situ adaptable and injectable interpenetrating polymer network (IPN) hydrogel is developed through an ingenious combination of a bio-orthogonal reaction between hyaluronic acid (HA) and collagen, along with effective electrostatic interactions leveraging bisphosphonate (BP)-functionalized HA macromers (HABP) and nanorod shaped zinc (Zn)-doped biphasic calcium phosphate (ZnBCP). IPN hydrogel exhibits exceptional adaptability to the local shape complexity at bone erosions, and by integrating ZnBCP and HABP, a multi-stage releasing platform is engineered, facilitating controlled cargo delivery for remodeling more anti-inflammatory M2 cells and reducing over-activated osteoclastic activities, thereby reconstructing the bone regeneration microenvironment. Sustainedly co-delivering multiple ions (calcium and phosphate) can display excellent osteogenic properties and be conducive to the bone formation process, by effects of osteogenesis-associated cell differentiation. Overall, the introduced bioactive IPN hydrogel therapy remodels the osteoimmune environment by synergistic pro-inflammation-resolving, osteogenesis, and anti-osteoclastic activities, displaying excellent bone reconstruction in the collagen-induced arthritis rabbit model.


Subject(s)
Arthritis, Rheumatoid , Hydrogels , Osteogenesis , Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/pathology , Animals , Osteogenesis/drug effects , Hydrogels/chemistry , Hydrogels/pharmacology , Rabbits , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/chemistry , Mice , Hyaluronic Acid/chemistry , Hyaluronic Acid/pharmacology , Humans , Bone Regeneration/drug effects , Cell Differentiation/drug effects , Osteoclasts/drug effects , Osteoclasts/metabolism , Bone Remodeling/drug effects , RAW 264.7 Cells
6.
Hum Reprod ; 39(5): 1131-1140, 2024 May 02.
Article in English | MEDLINE | ID: mdl-38511217

ABSTRACT

STUDY QUESTION: Do copy-number variations (CNVs) in the azoospermia factor (AZF) regions and monogenic mutations play a major role in the development of isolated (non-syndromic) non-obstructive azoospermia (NOA) in Japanese men with a normal 46, XY karyotype? SUMMARY ANSWER: Deleterious CNVs in the AZF regions and damaging sequence variants in eight genes likely constitute at least 8% and approximately 8% of the genetic causes, respectively, while variants in other genes play only a minor role. WHAT IS KNOWN ALREADY: Sex chromosomal abnormalities, AZF-linked microdeletions, and monogenic mutations have been implicated in isolated NOA. More than 160 genes have been reported as causative/susceptibility/candidate genes for NOA. STUDY DESIGN, SIZE, DURATION: Systematic molecular analyses were conducted for 115 patients with isolated NOA and a normal 46, XY karyotype, who visited our hospital between 2017 and 2021. PARTICIPANTS/MATERIALS, SETTING, METHODS: We studied 115 unrelated Japanese patients. AZF-linked CNVs were examined using sequence-tagged PCR and multiplex ligation-dependent probe amplification, and nucleotide variants were screened using whole exome sequencing (WES). An optimized sequence kernel association test (SKAT-O), a gene-based association study using WES data, was performed to identify novel disease-associated genes in the genome. The results were compared to those of previous studies and our in-house control data. MAIN RESULTS AND THE ROLE OF CHANCE: Thirteen types of AZF-linked CNVs, including the hitherto unreported gr/gr triplication and partial AZFb deletion, were identified in 63 (54.8%) cases. When the gr/gr deletion, a common polymorphism in Japan, was excluded from data analyses, the total frequency of CNVs was 23/75 (30.7%). This frequency is higher than that of the reference data in Japan and China (11.1% and 14.7%, respectively). Known NOA-causative AZF-linked CNVs were found in nine (7.8%) cases. Rare damaging variants in known causative genes (DMRT1, PLK4, SYCP2, TEX11, and USP26) and hemizygous/multiple-heterozygous damaging variants in known spermatogenesis-associated genes (TAF7L, DNAH2, and DNAH17) were identified in nine cases (7.8% in total). Some patients carried rare damaging variants in multiple genes. SKAT-O detected no genes whose rare damaging variants were significantly accumulated in the patient group. LIMITATIONS, REASONS FOR CAUTION: The number of participants was relatively small, and the clinical information of each patient was fragmentary. Moreover, the pathogenicity of identified variants was assessed only by in silico analyses. WIDER IMPLICATIONS OF THE FINDINGS: This study showed that various AZF-linked CNVs are present in more than half of Japanese NOA patients. These results broadened the structural variations of AZF-linked CNVs, which should be considered for the molecular diagnosis of spermatogenic failure. Furthermore, the results of this study highlight the etiological heterogeneity and possible oligogenicity of isolated NOA. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by Grants from the Japan Society for the Promotion of Science (21K19283 and 21H0246), the Japan Agency for Medical Research and Development (22ek0109464h0003), the National Center for Child Health and Development, the Canon Foundation, the Japan Endocrine Society, and the Takeda Science Foundation. The results of this study were based on samples and patient data obtained from the International Center for Reproductive Medicine, Dokkyo Medical University Saitama Medical Center, Koshigaya, Japan. The authors have no conflicts of interest to disclose. TRIAL REGISTRATION NUMBER: N/A.


Subject(s)
Azoospermia , Cell Cycle Proteins , DNA Copy Number Variations , Humans , Azoospermia/genetics , Male , Exome Sequencing , Adult , Mutation , Japan , Karyotyping
7.
Oncol Lett ; 27(3): 130, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38348386

ABSTRACT

Testicular cancer, the most common cancer among young male adults, is associated with infertility. A 38-year-old male patient was admitted to Dokkyo Medical University Saitama Medical Center, Japan, with infertility associated with severe oligozoospermia. Scrotal ultrasonography revealed two distinct tumors in the left testis: A mass with abundant blood flow on the cranial side and a mass with poor blood flow on the caudal side. Additional analysis revealed mild elevation of intact human chorionic gonadotropin (hCG) levels (tumor marker level assessment), high testosterone and low luteinizing hormone and follicle-stimulating hormone levels (hormonal level assessment) and severe oligoasthenozoospermia (semen assessment). The preoperative diagnosis was left-sided testicular cancer and severe oligoasthenozoospermia and the patient underwent left high orchiectomy and oncological testicular sperm extraction. Based on the pathological assessment, the cranial tumor was diagnosed as a seminoma with syncytiotrophoblastic cells, whereas the caudal tumor had only scar tissue with germ cell neoplasia in situ in the adjacent parenchyma. Following surgery, intact hCG and hormone levels of the patient were normalized, and the semen parameters (semen volume, sperm density, and motility) improved dramatically. To the best of our knowledge, the present case is the first report of two types of testicular tumor in a unilateral testis in a patient with a history of cryptorchidism surgery. The present case demonstrated that scrotal ultrasonography should be performed in patients with abnormal semen results to rule out testicular tumors.

8.
Transl Cancer Res ; 13(1): 57-64, 2024 Jan 31.
Article in English | MEDLINE | ID: mdl-38410216

ABSTRACT

Background: The hinotoriTM surgical robot system (HSRS) is the first made-in-Japan robotic system used for radical prostatectomy. Here, we report initial results and describe our learning curve (skill development) implementing robot-assisted radical prostatectomy using HSRS (h-RARP). Methods: Between November 2021 and December 2022, 97 patients who underwent h-RARP at our institution were enrolled in this study. We retrospectively evaluated the surgical outcomes of the initial cases using h-RARP, comparing those of RARP using da Vinci surgical robot system (d-RARP) in our institution. Furthermore, the learning curves of two surgeons with the highest number of h-RARP were analyzed. Patients treated by each surgeon were categorized into two groups: 1-15 cases (earlier group) and >15 cases (later group). Preoperative patient characteristics, operation parameters, and complication rates were compared between the two groups. Results: In terms of surgical outcome, h-RARP was comparable to d-RARP. The procedures performed by the HSRS were successfully completed in all cases. There was no complication of grade 3 or higher. Comparing the two surgeons, surgeon 1, who had performed 40 d-RARP procedures, had time using robot system of the later group that was significantly shorter than that of the earlier group. However, for surgeon 2 with more than 100 d-RARP procedures, there was no statistically significant difference in time using robot system between groups. Other parameters showed no difference between earlier and later groups for the two surgeons. Conclusions: Our results show that surgical outcomes of h-RARP are comparable to those of d-RARP during the initial experience of clinical application. In addition, the surgeons' learning curves for the total RARP experience suggest that the experience of d-RARP can carry over to performance using the novel HSRS.

10.
Transplant Proc ; 55(4): 1074-1077, 2023 May.
Article in English | MEDLINE | ID: mdl-37147192

ABSTRACT

For chronic myeloid leukemia (CML), a Philadelphia chromosome-positive myeloproliferative neoplasm, the introduction of tyrosine kinase inhibitors has transformed CML from a lethal disease into a manageable chronic disease with a close-to-normal life expectancy. Active malignancy is an absolute contraindication to kidney transplantation. However, it is controversial whether kidney transplantation can be safely performed in patients with a history of CML who are in remission. We describe the clinical course of a 64-year-old male patient with chronic kidney disease from diabetic nephropathy (DMN) who underwent living donor kidney transplantation. The patient was diagnosed with CML 15 years ago and promptly achieved cytogenetic and molecular biological remission after starting imatinib. After that, he continued imatinib treatment for 15 years and was in remission, but his chronic kidney disease from DMN gradually worsened. A preemptive living donor kidney transplant was performed in July 2020. Imatinib for CML was discontinued because the patient maintained deep molecular remission (DMR) of major molecular response for more than 15 years before kidney transplantation. After kidney transplantation, the transplanted kidney function remained good at approximate serum creatinine levels of 1.1 mg/dL without histopathologic rejection, and the 3 monthly BCR-ABL1 measurement results were negative and are in progress. Thus, he continues to maintain treatment-free remission status without imatinib for 26 months after renal transplantation. In conclusion, this result suggests that CML with long-lasting DMR on imatinib therapy can be considered an inactive malignancy and therefore a relative indication for kidney transplantation.


Subject(s)
Antineoplastic Agents , Kidney Transplantation , Leukemia, Myelogenous, Chronic, BCR-ABL Positive , Renal Insufficiency, Chronic , Male , Humans , Middle Aged , Imatinib Mesylate/therapeutic use , Kidney Transplantation/adverse effects , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/complications , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/surgery , Renal Insufficiency, Chronic/drug therapy , Remission Induction , Antineoplastic Agents/therapeutic use , Protein Kinase Inhibitors/therapeutic use , Treatment Outcome
11.
Transplant Proc ; 55(4): 1071-1073, 2023 May.
Article in English | MEDLINE | ID: mdl-37120342

ABSTRACT

BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is associated with several cardiovascular disorders, including aortic dissection, which preferentially occurs at the thoracic or abdominal level. Because there are few case reports describing surgical repair for aortic dissection followed by renal transplantation in patients with ADPKD, kidney transplantation performed after repair for aortic dissection remains challenging. CASE PRESENTATION: A 34-year-old Japanese man with end-stage renal disease secondary to ADPKD underwent thoracic endovascular aortic repair for complicated acute type B aortic dissection 12 months earlier. A contrast computed tomography scan before transplantation revealed an aortic dissection involving the descending aorta proximal to the common iliac arteries and confirmed multiple large bilateral renal cysts. After simultaneous right native nephrectomy, the patient underwent preemptive living-donor kidney transplantation obtained from his mother. Intraoperatively, we noted that dissection of the external iliac vessels was difficult because of dense adhesions. Arterial clamping was performed immediately below the bifurcation of the internal iliac artery to prevent further aortic dissection of the external iliac artery. After end-to-end anastomosis to the internal iliac artery was completed and the vascular clamp was released, the kidney began to produce urine immediately. CONCLUSION: This case suggests that kidney transplantation in patients undergoing endovascular aortic repair for aortic dissection can be performed by adequately applying a vascular clamp proximal to the internal iliac artery during vascular anastomosis.


Subject(s)
Aortic Aneurysm, Thoracic , Aortic Dissection , Blood Vessel Prosthesis Implantation , Endovascular Procedures , Kidney Transplantation , Polycystic Kidney, Autosomal Dominant , Male , Humans , Adult , Kidney Transplantation/adverse effects , Polycystic Kidney, Autosomal Dominant/complications , Polycystic Kidney, Autosomal Dominant/surgery , Endovascular Aneurysm Repair , Kidney/surgery , Aortic Dissection/diagnostic imaging , Aortic Dissection/etiology , Aortic Dissection/surgery , Aortic Aneurysm, Thoracic/diagnostic imaging , Aortic Aneurysm, Thoracic/etiology , Aortic Aneurysm, Thoracic/surgery , Endovascular Procedures/methods
12.
Transplant Proc ; 55(4): 1078-1080, 2023 May.
Article in English | MEDLINE | ID: mdl-37105827

ABSTRACT

BACKGROUND: Aortoiliac lesions can influence the results of kidney transplantation and increase technical difficulties during surgery. Aortic dissection (AD) is a rare and infrequently reported event before transplantation, whereas immediate optimal perfusion is paramount for kidney transplantation. Thus, adequate blood flow imposed by the flow from the true lumen must be considered when choosing a target inflow vessel. CASE PRESENTATION: A 67-year-old man on dialysis with end-stage renal disease caused by immunoglobulin A nephropathy was referred for kidney transplantation. He had successfully undergone conventional Stanford type A AD surgery 3 years ago. Pretransplant contrast-enhanced computed tomography angiography revealed termination of the distal intimal flaps within the common iliac arteries. Dilation of the descending aorta was also observed. Based on the meticulous vascular assessment, including consultation with the cardiovascular surgery department, the right internal iliac artery (IIA) was considered usable for anastomosis. He underwent living unrelated kidney transplantation from his 66-year-old wife. The patency and blood flow in the right IIA were also verified using intraoperative findings. Without any special procedure, we used a side-to-end arterial anastomosis between the donor renal artery and recipient IIA. After vascular clamp removal, the allograft was perfused homogeneously and immediately functioned. CONCLUSION: Patients receiving previous surgery for type A AD can successfully undergo kidney transplantation if the patency of the iliac arteries from the true lumen is confirmed by perioperative evaluation, and the artery can be carefully clamped to avoid possible further dissection.


Subject(s)
Aortic Dissection , Kidney Failure, Chronic , Kidney Transplantation , Male , Humans , Aged , Kidney Transplantation/adverse effects , Renal Dialysis , Kidney , Aortic Dissection/complications , Aortic Dissection/diagnostic imaging , Kidney Failure, Chronic/complications , Kidney Failure, Chronic/surgery , Iliac Artery/diagnostic imaging , Iliac Artery/surgery
13.
IJU Case Rep ; 6(2): 97-100, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36874990

ABSTRACT

Introduction: Regressed germ cell tumors are a rare disease commonly diagnosed with metastatic symptoms without local symptoms in the testis. Case presentation: A 33-year-old man with azoospermia was referred to our hospital. His right testis was slightly swollen, and ultrasonography revealed hypoechogenicity of the right testis with decreased blood flow. Right high orchiectomy was performed. Pathologically, the seminiferous tubules were absent or highly atrophied with vitrification degeneration; however, no neoplastic lesion was confirmed. One-month post-surgery, the patient noticed a mass in the left supraclavicular fossa, of which a biopsy revealed seminoma. The patient was diagnosed with a regressed germ cell tumor and underwent systemic chemotherapy. Conclusion: We reported the first case of a regressed germ cell tumor discovered due to complaints of azoospermia.

14.
Andrologia ; 54(11): e14588, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36100572

ABSTRACT

This study aimed to assess outcomes of microdissection testicular sperm extraction (MD-TESE) and identify predictors for sperm retrieval (SR) in patients with non-mosaic Klinefelter syndrome (NM-KFS). We retrospectively evaluated 37 patients with NM-KFS who underwent MD-TESE. Data of age at operation, body mass index (BMI), testicular volume, serum luteinizing hormone (LH), follicle stimulating hormone (FSH), preoperative and postoperative testosterone levels with reduction ratio between the two values, and FSH/preoperative testosterone ratio were analysed. These patients were divided into two groups according to success or failure of SR: the successful and failure groups. Factors related to SR were evaluated by statistical analyses using the Mann-Whitney U test and logistic regression modelling. Regarding these factors, the cut-off level was specified using the receiver operating characteristics (ROC) curve. Moreover, the percentage of SR at that level was assessed. A simple scoring model was developed based on the multivariate analysis. Fourteen patients underwent successful SR, whereas 23 experienced failure SR. Statistical analysis found preoperative testosterone and FSH levels to be significant factors associated with SR. On the ROC curve, the cut-off levels for preoperative testosterone and FSH were 2.34 ng/ml and 33.2 mIU/ml respectively. A new scoring model was developed, consisting of preoperative testosterone (≥2.34 ng/ml) and FSH (≤33.2 mIU/ml). The sperm retrieval rates (SRRs) were clearly discriminated by stratification according to the scoring model. The SRR of the cases of scores of 2, 1 and 0 were 87.5%, 31.6% and 10% respectively. At our hospital, the SRR of MD-TESE in patients with NM-KFS was 37.8%. The patients with high testosterone and low FSH levels tended to demonstrate successful SR.


Subject(s)
Azoospermia , Klinefelter Syndrome , Humans , Male , Sperm Retrieval , Microdissection , Klinefelter Syndrome/surgery , Klinefelter Syndrome/complications , Testosterone , Retrospective Studies , Semen , Testis/surgery , Spermatozoa , Follicle Stimulating Hormone
15.
Pharmaceutics ; 14(5)2022 May 23.
Article in English | MEDLINE | ID: mdl-35631697

ABSTRACT

Chitosan is a cationic polymer that forms polymerized membranes upon reaction with anionic polymers. Chitosan-carboxymethyl cellulose (CMC) capsules are drug delivery carrier candidates whose mechanical strength and permeability must be controlled to achieve sustained release. In this study, the capsules were prepared from chitosan-γ-glycidoxypropyltrimethoxysilane (GPTMS)-CMC. The mechanical stability of the capsules was improved by crosslinking the chitosan with GPTMS. The capsules were then coated with hydroxyapatite (HAp) by alternately soaking them in calcium chloride solution and disodium hydrogen phosphate solution to prevent rapid initial drug release. Cytochrome C (CC), as a model drug, was introduced into the capsules via two routes, impregnation and injection, and then the CC released from the capsules was examined. HAp was found to be deposited on the internal and external surfaces of the capsules. The amount of CC introduced, and the release rate were reduced by the HAp coating. The injection method was found to result in the greatest CC loading.

16.
Materials (Basel) ; 15(5)2022 Feb 25.
Article in English | MEDLINE | ID: mdl-35268978

ABSTRACT

Titanium alloy is widely applied in aerospace, medical, shipping and other fields due to its high specific strength and low density. The purpose of this study was to analyze the formability of Ti6Al4V alloys at elevated temperatures. An accurate constitutive model is the basic condition for accurately simulating the plastic forming of materials, and it is an important basis for optimizing the parameters of the hot forging forming process. In this study, the optimization algorithm was used to accurately identify the high-temperature constitutive model parameters of Ti6Al4V titanium alloy, and the hot working diagram was established to optimize the hot forming process parameters. The optimal forming conditions of Ti6Al4V titanium alloy are given. Ti6Al4V alloy was subjected to high-temperature compression tests at 800-1000 °C and at strain rates of 0.01-5 s-1 on a Gleeble-1500D thermal/mechanical simulation machine. Each parameter of the Hansel-Spittel constitutive model was taken as an independent variable, and the accumulated error between the stress calculated by the constitutive model and the stress obtained by experimentation was used as an objective function. Based on response surface methodology, an inverse optimization method for identifying the parameters of the high-temperature constitutive model of Ti6Al4V alloy is proposed in this paper. An orthogonal test design was adopted to obtain sample point data, and a third-order response surface approximate model was established. The genetic algorithm (GA) was applied to reversely optimize the parameters of the constitutive model. To verify the accuracy of the optimized constitutive model, the average absolute relative error (AARE) and correlation coefficient (R) were used to evaluate the reliability of optimized constitutive model. The R value of the model was 0.999, and the AARE value was 0.048, respectively, indicating that the established high-temperature constitutive model for Ti6Al4V alloy has good calculation accuracy. The flow stress behavior of the material could be accurately delineated. Meanwhile, in order to study the formability of Ti6Al4V alloy, the hot processing map of the alloy, based on a dynamic material model, was established in this paper. The optimum hot working domains of the Ti6Al4V alloy were determined within 840-920 °C/0.01-0.049 s-1 and 940-980 °C/0.11-1.65 s-1; the hot processing map was verified in combination with the microstructure, and the fine and equiaxed grains and a large amount of ß phase could be found at 850 °C/0.01 s-1.

17.
Transplant Proc ; 54(2): 325-328, 2022 Mar.
Article in English | MEDLINE | ID: mdl-35065833

ABSTRACT

PURPOSE: This study aimed to analyze the incidence of subclinical rejection (SCR) in kidney transplantation patients and risk factors associated with SCR. METHODS: We assessed 80 protocol biopsies taken within 2 years postoperatively in 41 adult patients who underwent living donor kidney transplantation between 2017 and 2020. All patients were on immunosuppressant therapy that included tacrolimus, mycophenolate mofetil, and steroids. RESULTS: The prevalence of Banff Borderline classification at 3, 6, and 12 months after transplantation was 4%, 5%, and 8 %, respectively, whereas none of the biopsies met the Banff criteria for acute T cell-mediated rejection throughout the study period. Active antibody-mediated rejection (ABMR) was only present in 8% of patients at 3 months after transplantation and chronic active ABMR at 6, 12, and 24 months after transplantation was detected in 10%, 13%, and 11% of the patients, respectively. Subgroup analysis revealed that 50% of the 6 patients with preformed anti-donor specific antibodies (DSAs) developed clinical or subclinical active ABMR within 3 months after transplantation, followed by chronic active ABMR according to serial histologic assessment. Conversely, only a small proportion of patients (3%) without preformed DSAs exhibited clinically active ABMR. CONCLUSIONS: SCR occurs too infrequently in patients with low immunologic risk and strong contemporary immunosuppression therapy to justify the diagnostic effort of serial protocol biopsies. However, protocol biopsies remain an indispensable tool in renal transplant monitoring and may be especially important in immunologically high-risk patients with pre-existing DSAs.


Subject(s)
Kidney Transplantation , Adult , Allografts , Biopsy , Graft Rejection , Humans , Kidney/pathology , Kidney Transplantation/adverse effects , Tacrolimus/therapeutic use
18.
Asian J Androl ; 24(1): 40-44, 2022.
Article in English | MEDLINE | ID: mdl-34121749

ABSTRACT

Semen analysis has long been used to evaluate male fertility. Recently, several sperm function tests have been developed. Of those, the sperm DNA fragmentation index (DFI), which describes the status of the sperm DNA, is thought to be a suitable parameter for evaluating male fertility. However, there have been no large-scale studies on the sperm DFI of Japanese men. Therefore, we investigated the feasibility of using an in-house flow cytometry-based sperm DFI analysis based on the sperm DNA fragmentation test of sperm chromatin structure assay (SCSA) to assess male fertility in Japan. This study enrolled 743 infertile and 20 fertile Japanese men. To evaluate reproducibility, inter- and intraobserver precision was analyzed. A receiver operating characteristic curve analysis was used to set a cutoff value for the sperm DFI to identify men who could father children by timed intercourse or intrauterine insemination. The variability of the sperm DFI among fertile volunteers was determined. The relationship between semen parameters and the sperm DFI was assessed by Spearman's rho test. A precision analysis revealed good reproducibility of the sperm DFI. The cutoff value of sperm DNA fragmentation in infertile men was 24.0%. Semen volume had no relationship with the sperm DFI. Sperm concentration, sperm motility, total motile sperm count, and percentage of normal-shaped sperm were significantly and negatively correlated with the sperm DFI. The median sperm DFI was smaller in fertile volunteers (7.7%) than that in infertile men (19.4%). Sperm DNA fragmentation analysis can be used to assess sperm functions that cannot be evaluated by ordinary semen analysis.


Subject(s)
Infertility, Male , Sperm Motility , Child , Chromatin , DNA Fragmentation , Flow Cytometry , Humans , Infertility, Male/diagnosis , Infertility, Male/genetics , Japan , Male , Reproducibility of Results , Spermatozoa
19.
Hum Fertil (Camb) ; 25(1): 142-146, 2022 Feb.
Article in English | MEDLINE | ID: mdl-31955637

ABSTRACT

Varicocele is a common cause of male infertility. It is reported that low sperm concentration, motility and morphology are indicative of increased sperm DNA fragmentation index (DFI) in men with varicocele. Although research has been conducted into the relationship between varicocele and DFI, little is known about seminal oxidation-reduction potential (ORP) in varicocele patients. We assessed the relationship between varicocele with seminal ORP and sperm DFI in both fertile and infertile men. This prospective case-control study compared the findings from infertile men with varicocele to those of men with normal spermatogenesis without varicocele. Semen samples were collected and assessed using the WHO (2010) guidelines. ORP was measured (mV) and normalized to sperm concentration (mV/106 sperm/mL). DFI was measured using the sperm chromatin structure assay (SCSA) method. For group comparisons, only samples with a concentration >1 × 106 sperm/mL were included. Infertile men with varicocele had significantly lower mean sperm concentration, motility and total sperm count. Conversely, infertile men with varicocele had a significantly higher mean serum FSH level, and higher ORP and DFI values than fertile controls. ORP was higher in patients with varicocele and positively correlated with DFI (p < 0.01). ORP and DFI showed significant negative correlations with semen parameters (sperm concentration, motility and total sperm count) in infertile men with a varicocele.


Subject(s)
Infertility, Male , Varicocele , Case-Control Studies , DNA Fragmentation , Humans , Infertility, Male/genetics , Male , Oxidation-Reduction , Semen , Sperm Count , Sperm Motility , Spermatozoa/metabolism , Varicocele/complications
20.
Materials (Basel) ; 14(8)2021 Apr 14.
Article in English | MEDLINE | ID: mdl-33919911

ABSTRACT

In order to avoid the stress shielding phenomenon in orthopedic bionic bone implantation, it is necessary to consider the design of mechanical compatible implants imitating the host bone. In this study, we developed a novel cancellous bone structure design method aimed at ensuring the mechanical compatibility between the bionic bone and human bone by means of computer-aided design (CAD) and finite element analysis technology (specifically, finite element modeling (FEM)). An orthogonal lattice model with volume porosity between 59% and 96% was developed by means of CAD. The effective equivalent elastic modulus of a honeycomb structure with square holes was studied by FEM simulation. With the purpose of verifying the validity of the cancellous bone structure design method, the honeycomb structure was fabricated by selective laser sintering (SLS) and the actual equivalent elastic modulus of the honeycomb structure was measured with a uniaxial compression test. The experimental results were compared with the FEM values and the predicted values. The results showed that the stiffness values of the designed structures were within the acceptable range of human cancellous bone of 50-500 MPa, which was similar to the stiffness values of human vertebrae L1 and L5. From the point of view of mechanical strength, the established cellular model can effectively match the elastic modulus of human vertebrae cancellous bone. The functional relationship between the volume porosity of the nylon square-pore honeycomb structure ranging from 59% to 96% and the effective elastic modulus was established. The effect of structural changes related to the manufacture of honeycomb structures on the equivalent elastic modulus of honeycomb structures was studied quantitatively by finite element modeling.

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