Case report: remedial microdissection testicular sperm extraction after onco-microdissection testicular sperm extraction failure.

BACKGROUND: Testicular cancer (TC) mostly occurs in men aged 14 to 44. Studies have shown that TC seriously damages male fertility, and 6% to 24% of patients with TC were even found to suffer from azoospermia when they are diagnosed. At present, some studies have pointed out that onco-microdissection testicular sperm extraction (mTESE) can extract sperm from tumor testicles. However, there are almost no reports on remedial measures after onco-mTESE failure. Given the valuable opportunity for fertility preservation in patients with TC and azoospermia, it is necessary to provide effective remedial methods for patients with failed onco-mTESE. METHODS: Two young men, who were diagnosed with TC and also found to have azoospermia, tried onco-mTESE while undergoing radical orchiectomy for fertility preservation. However, sperm extraction failed in both patients. Subsequently, the isolated testicular tissue of the patient in case 1 suffered from TC again, and the patient in case 2 was scheduled to receive multiple cycles of gonadotoxic chemotherapy. Because both had a plan to have a birth in the future, we performed remedial mTESE. RESULTS: Sperm was successfully extracted from both patients. The patient recovered well, without complications. The patient couple in case 1 underwent 1 intracytoplasmic sperm injection (ICSI) cycle but did not achieve clinical pregnancy. CONCLUSIONS: There is still an opportunity to extract sperm successfully using onco-mTESE, despite the difficulty of fertility preservation in TC patients with azoospermia. If sperm extraction from the tumor testis fails, implementing remedial mTESE as early as possible would likely preserve the last chance of fertility for these patients.

Genomic and transcriptomic profiling of combined small-cell lung cancer through microdissection: unveiling the transformational pathway of mixed subtype.

BACKGROUND: Combined small-cell lung carcinoma (cSCLC) represents a rare subtype of SCLC, the mechanisms governing the evolution of cancer genomes and their impact on the tumor immune microenvironment (TIME) within distinct components of cSCLC remain elusive. METHODS: Here, we conducted whole-exome and RNA sequencing on 32 samples from 16 cSCLC cases. RESULTS: We found striking similarities between two components of cSCLC-LCC/LCNEC (SCLC combined with large-cell carcinoma/neuroendocrine) in terms of tumor mutation burden (TMB), tumor neoantigen burden (TNB), clonality structure, chromosomal instability (CIN), and low levels of immune cell infiltration. In contrast, the two components of cSCLC-ADC/SCC (SCLC combined with adenocarcinoma/squamous-cell carcinoma) exhibited a high level of tumor heterogeneity. Our investigation revealed that cSCLC originated from a monoclonal source, with two potential transformation modes: from SCLC to SCC (mode 1) and from ADC to SCLC (mode 2). Therefore, cSCLC might represent an intermediate state, potentially evolving into another histological tumor morphology through interactions between tumor and TIME surrounding it. Intriguingly, RB1 inactivation emerged as a factor influencing TIME heterogeneity in cSCLC, possibly through neoantigen depletion. CONCLUSIONS: Together, these findings delved into the clonal origin and TIME heterogeneity of different components in cSCLC, shedding new light on the evolutionary processes underlying this enigmatic subtype.

Predictors of successful salvage microdissection testicular sperm extraction (mTESE) after failed initial TESE in patients with non-obstructive azoospermia: A systematic review and meta-analysis.

BACKGROUND: There has been no systematic review and meta-analysis to analyze and summarize the predictive factors of successful sperm extraction in salvage microdissection testicular sperm extraction. OBJECTIVES: We aimed to investigate the factors predicting the result of salvage microdissection testicular sperm extraction in patients with non-obstructive azoospermia who failed the initial microdissection testicular sperm extraction or conventional testicular sperm extraction. MATERIALS AND METHODS: We conducted a systematic literature search in PubMed, Web of Science, EMBASE, and the Cochrane Library for literature that described the characteristics of patients with non-obstructive azoospermia who underwent salvage microdissection testicular sperm extraction after failing the initial microdissection testicular sperm extraction or conventional testicular sperm extraction published prior to June 2022. RESULTS: This meta-analysis included four retrospective studies with 332 patients with non-obstructive azoospermia who underwent a failed initial microdissection testicular sperm extraction and three retrospective studies with 177 non-obstructive azoospermia patients who underwent a failed conventional testicular sperm extraction. The results were as follows: among non-obstructive azoospermia patients whose first surgery was microdissection testicular sperm extraction, younger patients (standard mean difference: -0.28, 95% confidence interval [CI]: -0.55 to -0.01) and those with smaller bilateral testicular volume (standard mean difference: -0.55, 95% CI: -0.95 to -0.15), lower levels of follicle-stimulating hormone (standard mean difference: -0.86, 95% CI: -1.18 to -0.54) and luteinizing hormone (standard mean difference: -0.68, 95% CI: -1.16 to -0.19), and whose testicular histological type was hypospermatogenesis (odds ratio: 3.52, 95% CI: 1.30-9.53) were more likely to retrieve spermatozoa successfully, while patients with Sertoli-cell-only syndrome (odds ratio: 0.41, 95% CI: 0.24-0.73) were more likely to fail again in salvage microdissection testicular sperm extraction. Additionally, in patients who underwent salvage microdissection testicular sperm extraction after a failed initial conventional testicular sperm extraction, those with testicular histological type of hypospermatogenesis (odds ratio: 30.35, 95% CI: 8.27-111.34) were more likely to be successful, while those with maturation arrest (odds ratio: 0.39, 95% CI: 0.18-0.83) rarely benefited. CONCLUSION: We found that age, testicular volume, follicle-stimulating hormone, luteinizing hormone, hypospermatogenesis, Sertoli-cell-only syndrome, and maturation arrest were valuable predictors of salvage microdissection testicular sperm extraction, which will assist andrologists in clinical decision-making and minimize unnecessary injury to patients.

A Prediction Model of Sperm Retrieval in Males with Idiopathic Non-obstructive Azoospermia for Microdissection Testicular Sperm Extraction.

Patients with Idiopathic non-obstructive azoospermia (iNOA) can achieve fertility by extracting testicular sperm through microdissection testicular sperm extraction (mTESE). But more than half of iNOA patients still cannot benefit from mTESE. In recent years, some studies had reported that serum hormones may be related to the outcome of sperm retrieval, but few had been verified. We hope to obtain a predictive method that is convenient for clinical application and can help judge the outcome of sperm extraction before implementing mTESE. We performed a retrospective analysis of NOA patients who underwent mTESE in the same andrology center from June 2020 to November 2022. A total of 261 patients with complete data were collected, logistic regression analysis was performed and a predictive model was constructed. Then, from December 2022 to May 2023, one prospective cohort of 48 NOA patients who met the inclusion criteria from the same center was recruited to validate the risk prediction model. We successfully constructed a logistic regression model to predict the outcome of iNOA patients undergoing mTESE and found that higher serum anti-Müllerian hormone (AMH) levels were associated with failure sperm retrieval, resulting in an AMH cut-off of 2.60 ng/ml. The area under the receiver operating curve was 0.811, the sensitivity was 0.870, and the specificity was 0.705. Decision curve analysis demonstrated that the threshold probability was above 4%, and unnecessary mTESE could be reduced using this model. In a prospective cohort at the same center, 85.42% (41/48) of iNOA patients correctly identified the mTESE outcome using this model. A logistic regression model with AMH as an independent predictor can predict mTESE outcomes in iNOA patients. Preoperative selection of mTESE in patients with iNOA using this model had clinical benefit in reducing unnecessary surgery. The model demonstrated good accuracy in a small prospective cohort validation.

Sperm retrieval outcomes of contralateral testis in men with nonobstructive azoospermia and unsuccessful unilateral microdissection testicular sperm extraction.

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Clinical management of nonobstructive azoospermia: An update.

Approximately 1% of the general male population has azoospermia, and nonobstructive azoospermia accounts for the majority of cases. The causes vary widely, including chromosomal and genetic abnormalities, varicocele, drug-induced causes, and gonadotropin deficiency; however, the cause is often unknown. In azoospermia caused by hypogonadotropic hypogonadism, gonadotropin replacement therapy can be expected to produce sperm in the ejaculate. In some cases, upfront varicocelectomy for nonobstructive azoospermia with varicocele may result in the appearance of ejaculated spermatozoa; however, the appropriate indication should be selected. Each guideline recommends microdissection testicular sperm extraction for nonobstructive azoospermia in terms of successful sperm retrieval and avoidance of complications. Sperm retrieval rates generally ranged from 20% to 70% but vary depending on the causative disease. Various attempts have been made to predict sperm retrieval and improve sperm retrieval rates; however, the evidence is insufficient. Further evidence accumulation is needed for salvage treatment in cases of failed sperm retrieval. In Japan, there is inadequate provision on the right to know the origin of children born from artificial insemination of donated sperm and the rights of sperm donors, as well as information on unrelated family members, and the development of these systems is challenging. In the future, it is hoped that the pathogenesis of nonobstructive azoospermia with an unknown cause will be elucidated and that technology for omics technologies, human spermatogenesis using pluripotent cells, and organ culture methods will be developed.

Microdissection testicular sperm extraction outcomes in azoospermic patients with bilateral orchidopexy.

BACKGROUND: Cryptorchidism is considered to be one of the most common causes of non-obstructive azoospermia. There are several surgical techniques to retrieve sperm in these patients. Microdissection testicular sperm extraction (m-TESE) is a recent sperm retrieval technique which is considered to be a safe, non-blind, and feasible method. OBJECTIVES: This study aimed to investigate sperm retrieval rate (SRR) by the mTESE method in patients who have undergone orchidopexy due to bilateral cryptorchidism. MATERIALS AND METHODS: In this retrospective study, 56 ex-cryptorchid patients, who underwent mTESE due to post orchidopexy azoospermia, were included. Patients with hypogonadotropic hypogonadism, Klinefelter syndrome, azoospermia factors (AZF) microdeletion, or chromosomal translocation were excluded from the study. Data were obtained from medical files. RESULTS: SRR in this study was 46%. Patients were divided into two groups of negative (n = 30) and positive (n = 26) based on the sperm extraction outcomes. There was no statistically significant difference between two groups regarding the mean age at mTESE, mean age at orchidopexy, testicular size, and serum testosterone concentration. However, testicular location, histological patterns, FSH, and LH level showed to have statistically significant relation with sperm retrieval results. But, according to our logistic regression, none of the included variable in the model including FSH, LH, histopathology, and testis location have a significant effect on the presence of the sperm. DISCUSSION: In the present study, SRR was significantly higher in patients with scrotal testis and low level of FSH and LH. CONCLUSIONS: Performing mTESE could be recommended in ex-cryptorchid patients with post orchidopexy NOA. Preoperative testicular biopsy seems to be unnecessary while clinical criteria can perfectly define NOA.

Microdissection and Immunofluorescence Staining of Myocardial Sleeves in Murine Pulmonary Veins.

Pulmonary veins (PVs) are the major source of ectopic beats in atrial arrhythmias and play a crucial role in the development and progression of atrial fibrillation (AF). PVs contain myocardial sleeves (MS) composed of cardiomyocytes. MS are implicated in the initiation and maintenance of AF, as they preserve similarities to the cardiac working myocardium, including the ability to generate ectopic electrical impulses. Rodents are widely used and may represent excellent animal models to study the pulmonary vein myocardium since cardiomyocytes are widely present all over the vessel wall. However, precise microdissection and preparation of murine PVs is challenging due to the small organ size and intricate anatomy. We demonstrate a microscopy-guided microdissection protocol for isolating the murine left atrium (LA) together with the PVs. Immunofluorescence staining using cardiac Troponin-T (cTNT) and connexin 43 (Cx43) antibodies is performed to visualize the LA and PVs in full length. Imaging at 10x and 40x magnification provides a comprehensive view of the PV structure as well as detailed insights into the myocardial architecture, particularly highlighting the presence of connexin 43 within the MS.

How we do it: the Zurich Microsurgery Lab technique for placenta preparation.

BACKGROUND: Perfused placentas provide an excellent and accessible model for microvascular dissection, microsuturing and microanastomosis training - particularly in the early microsurgical learning curve. This way, a significant amount of live animals can be spared. METHOD: We present the Zurich Microsurgery Lab protocol, detailing steps for obtaining, selecting, cleaning, flushing, cannulating, and preserving human placentas - as well as microsurgical training examples - in a tried-and-true, safe, cost-effective, and high-yield fashion. CONCLUSION: Our technique enables highly realistic microsurgical training (microdissection, microvascular repair, microanastomosis) based on readily available materials. Proper handling, preparation, and preservation of the perfused placenta models is key.

Evolutionary histories of breast cancer and related clones.

Recent studies have documented frequent evolution of clones carrying common cancer mutations in apparently normal tissues, which are implicated in cancer development1-3. However, our knowledge is still missing with regard to what additional driver events take place in what order, before one or more of these clones in normal tissues ultimately evolve to cancer. Here, using phylogenetic analyses of multiple microdissected samples from both cancer and non-cancer lesions, we show unique evolutionary histories of breast cancers harbouring der(1;16), a common driver alteration found in roughly 20% of breast cancers. The approximate timing of early evolutionary events was estimated from the mutation rate measured in normal epithelial cells. In der(1;16)(+) cancers, the derivative chromosome was acquired from early puberty to late adolescence, followed by the emergence of a common ancestor by the patient's early 30s, from which both cancer and non-cancer clones evolved. Replacing the pre-existing mammary epithelium in the following years, these clones occupied a large area within the premenopausal breast tissues by the time of cancer diagnosis. Evolution of multiple independent cancer founders from the non-cancer ancestors was common, contributing to intratumour heterogeneity. The number of driver events did not correlate with histology, suggesting the role of local microenvironments and/or epigenetic driver events. A similar evolutionary pattern was also observed in another case evolving from an AKT1-mutated founder. Taken together, our findings provide new insight into how breast cancer evolves.

Precise microdissection of gastric mixed adeno-neuroendocrine carcinoma dissects its genomic landscape and evolutionary clonal origins.

Gastric mixed adenoneuroendocrine carcinoma (MANEC) is a clinically aggressive and heterogeneous tumor composed of adenocarcinoma (ACA) and neuroendocrine carcinoma (NEC). The genomic properties and evolutionary clonal origins of MANEC remain unclear. We conduct whole-exome and multiregional sequencing on 101 samples from 33 patients to elucidate their evolutionary paths. We identify four significantly mutated genes, TP53, RB1, APC, and CTNNB1. MANEC resembles chromosomal instability stomach adenocarcinoma in that whole-genome doubling in MANEC is predominant and occurs earlier than most copy-number losses. All tumors are of monoclonal origin, and NEC components show more aggressive genomic properties than their ACA counterparts. The phylogenetic trees show two tumor divergence patterns, including sequential and parallel divergence. Furthermore, ACA-to-NEC rather than NEC-to-ACA transition is confirmed by immunohistochemistry on 6 biomarkers in ACA- and NEC-dominant regions. These results provide insights into the clonal origin and tumor differentiation of MANEC.

Prediction of microdissection testicular sperm extraction outcomes of azoospermic patients post-chemotherapy using cyclophosphamide equivalent dose.

PURPOSE: We determined the sperm retrieval rate in men with persistent azoospermia post-chemotherapy in relation to cyclophosphamide equivalent dose (CED), a unit for quantifying alkylating agent exposure. METHODS: Medical records were retrospectively reviewed of 1098 patients diagnosed with non-obstructive azoospermia who had undergone microdissection testicular sperm extraction (mTESE) between January 2010 and 2021 at our institution. Twenty-three patients with a prior history of chemotherapy were included in the study. Oncological data, chemotherapy regime, and dosage were reviewed. The pretreatment hormone profile, CED, and mTESE outcomes were analyzed. RESULTS: Testicular spermatozoa were successfully retrieved from 11 patients (47%). The mean patient age was 37.3 years (range, 27-41 years), and mean time interval from chemotherapy to mTESE, 11.8 years (range, 1-45 years). Patients exposed to alkylating agents had significantly lower sperm retrieval rates than those not exposed to alkylating agents (1/9, 11% vs. 10/14, 71%, p = 0.009). No men with CED > 4000 mg/m2 (n = 6) had viable sperm in the testes during mTESE. Moreover, patients diagnosed with testicular non-seminomatous germ cell tumors had a favorable sperm retrieval rate (67%) compared to patients with lymphoma (20%) or leukemia (33%). CONCLUSION: Patients with permanent azoospermia post-chemotherapy have a lower testicular sperm retrieval rate when the chemotherapy regimen included alkylating agents. In cases where patients have undergone more intensive gonadotoxic treatments, such as higher CED, the likelihood of successful sperm retrieval is low. It is advisable to counsel such patients using the CED model prior to considering surgical sperm retrieval.

Comparison of unilateral and bilateral microdissection testicular sperm extraction (MD-TESE) in patients with non-obstructive azoospermia: a prospective study.

OBJECTIVE: To compare sperm retrieval rates between unilateral and bilateral microdissection testicular sperm extraction (MD-TESE) procedures in patients with non-obstructive azoospermia and to contribute to the literature by comparing them with literature data. METHODS: This prospective study included 84 males with primary infertility who had azoospermic NOA, who had been married for at least one year, and whose female partners did not have a history of infertility. The study was conducted between January 2019 and January 2020. MD-TESE was applied bilaterally to 48% (n:41) (Group 1) and unilaterally to 52% (n:43) (Group 2) of the patients, and sperm retrieval rates were compared. RESULTS: There was no statistically significant difference between Group 1 patients and Group 2 patients in terms of sperm availability (61%, 56.5%, p=0.495, respectively). In addition, while no complications were observed in unilateral MD-TESEs, 3 complications were observed in bilateral MD-TESEs. CONCLUSIONS: In our study, it was determined that there was no significant difference between the groups in terms of sperm availability in patients with NOA. Considering the operative time and complication rates of bilateral MD-TESE in patients diagnosed with NOA and the possible MD-TESE procedures that may be performed later, we believe that unilateral MD TESE is a more preferable procedure for the patient and surgeon in this patient group.

Technical report: surgical preparation of human brain tissue for clinical and basic research.

BACKGROUND: The study of the distinct structure and function of the human central nervous system, both in healthy and diseased states, is becoming increasingly significant in the field of neuroscience. Typically, cortical and subcortical tissue is discarded during surgeries for tumors and epilepsy. Yet, there is a strong encouragement to utilize this tissue for clinical and basic research in humans. Here, we describe the technical aspects of the microdissection and immediate handling of viable human cortical access tissue for basic and clinical research, highlighting the measures needed to be taken in the operating room to ensure standardized procedures and optimal experimental results. METHODS: In multiple rounds of experiments (n = 36), we developed and refined surgical principles for the removal of cortical access tissue. The specimens were immediately immersed in cold carbogenated N-methyl-D-glucamine-based artificial cerebrospinal fluid for electrophysiology and electron microscopy experiments or specialized hibernation medium for organotypic slice cultures. RESULTS: The surgical principles of brain tissue microdissection were (1) rapid preparation (<1 min), (2) maintenance of the cortical axis, (3) minimization of mechanical trauma to sample, (4) use of pointed scalpel blade, (5) avoidance of cauterization and blunt preparation, (6) constant irrigation, and (7) retrieval of the sample without the use of forceps or suction. After a single round of introduction to these principles, multiple surgeons adopted the technique for samples with a minimal dimension of 5 mm spanning all cortical layers and subcortical white matter. Small samples (5-7 mm) were ideal for acute slice preparation and electrophysiology. No adverse events from sample resection were observed. CONCLUSION: The microdissection technique of human cortical access tissue is safe and easily adoptable into the routine of neurosurgical procedures. The standardized and reliable surgical extraction of human brain tissue lays the foundation for human-to-human translational research on human brain tissue.

Microdissection of the Rodent Eye.

The ocular micro-dissection of the rodent eye involves the segmentation of the enucleated eyeball with the attached nictitating membrane, or third eyelid, to obtain the anterior and posterior eyecups. With this technique, the sub-parts of the eye, including the corneal tissue, neural tissue, retinal pigment epithelial (RPE) tissue, and lens, can be obtained for wholemounts, cryo-sectioning, and/or single-cell suspensions of a specific ocular tissue. The presence of the third eyelid presents unique and significant advantages, as it benefits the maintenance of the orientation of the eye, which is important for understanding eye physiology following any localized intervention or in studies involving ocular analysis relating to the eye's spatial topography. In this method, we enucleated the eyeball at the socket along with the third eyelid by carefully and slowly cutting through the extraocular muscles and severing the optic nerve. The eyeball was pierced through the corneal limbus using a microblade. The incision was used as the point of entry, allowing for cutting along the corneal-scleral junction by inserting micro-scissors through the incision point. Small and continuous cuts along the circumference were made until the cups separated. These could be further dissected by gently peeling the translucent layer of the neural retina using Colibri suturing forceps to obtain the neural retina and RPE layers. Further, three/four equidistant cuts were made from the periphery perpendicularly to the optic center until the optic nerve was reached. This opened the hemispherical cups into a floret shape so that they fell flat and could be easily mounted. This technique has been used in our lab for corneal wholemounts and retinal sections. The presence of the third eyelid delineates the nasal-temporal orientation, which allows for the study of various cell therapy interventions post-transplantation and, thus, the targeted physiological validation vital for visualization and accurate representation in such studies.

Analysis of the efficacy of microdissection of paravebous sinus meningiomas invading large venous sinuses.

OBJECTIVE: The management of paravebous sinus meningiomas that invade major venous sinuses is a subject of debate, particularly concerning the necessity of complete resection of the tumor and reconstruction of the venous sinus. This article aims to demonstrate the outcomes of total removal of the lesion (including the invading venous sinus portion) and the effects of restoring or not restoring venous circulation in terms of recurrence of the tumor, mortality, and post-operative complications. METHODS: The authors conducted a study involving 68 patients with paravebous sinus meningiomas. Of the 60 parasagittal meningiomas, 23 were located in the anterior third, 30 in the middle third, and 7 in the posterior third. Additionally, 3 lesions were located in the sinus confluence area, and 5 in the transverse sinus. All patients underwent surgery, and the degree of venous sinus involvement was classified into six types. For type I meningiomas, the outer layer of the sinus wall was stripped off. For types II to VI, two strategies were employed: non-constitutional, wherein the tumor and affected venous sinuses were removed without repair, and reconstructive, wherein the tumor was completely removed and the venous sinuses were sutured or repaired. Karnofsky Performance Status (KPS) scale and Magnetic Resonance Venography (MRV) were utilized to assess the outcomes of the surgical procedures. RESULTS: The study group of 68 patients underwent complete tumor resection in 97.1%, with sinus reconstruction attempted in 84.4% of cases with sinus wall and sinus cavity invasion. The recurrence rate of this group was 5.9%, with follow-up ranging from 33 to 57 months. It was found that the recurrence rate was significantly higher in cases with incomplete resection than in those with complete resection. The overall mortality rate was 4.4%, with all cases resulting from malignant brain swelling due to the failure to perform venous reconstruction after resectioning of the meningioma type VI. Furthermore, 10.3% of patients experienced worsening symptoms of neurological deficits or complete loss of neurological function, with a significantly higher incidence in those without venous reconstruction than in the venous reconstruction group (P < 0.0001, Fisher test). No statistically significant pre-operative and post-operative KPS differences were observed in patients with type I to V. However, in patients with type VI (who did not receive venous reconstruction), the post-operative KPS score was significantly worse. CONCLUSION: The results of this study suggest the necessity of a complete resection of the tumor, including the invasive venous sinus component, as the recurrence rate was found to be relatively low at 5.9%. Moreover, patients who did not undergo venous reconstruction showed significant deterioration in their clinical condition compared to other subgroups, thus highlighting the importance of venous sinus reconstruction.

Segment-Dependent Gene Expression Profiling of the Cartilaginous Fish Nephron Using Laser Microdissection for Functional Characterization of Nephron at Segment Levels.

For adaptation to a high salinity marine environment, cartilaginous fishes have evolved a ureosmotic strategy. They have a highly elaborate "four-loop nephron" in the kidney, which is considered to be important for reabsorption of urea from the glomerular filtrate to maintain a high concentration of urea in the body. However, the function and regulation, generally, of the "four-loop nephron" are still largely unknown due to the complicated configuration of the nephron and its many subdivided segments. Laser microdissection (LMD) followed by RNA-sequencing (RNA-seq) analysis is a powerful technique to obtain segment-dependent gene expression profiles. In the present study, using the kidney of cloudy catshark, Scyliorhinus torazame, we tested several formaldehyde-free and formaldehyde-based fixatives to optimize the fixation methods. Fixation by 1% neutral buffered formalin for 15 min resulted in sufficient RNA and structural integrities, which allowed LMD clipping of specific nephron segments and subsequent RNA-seq analysis. RNA-seq from the LMD samples of the second-loop, the fourth-loop, and the five tubular segments in the bundle zone revealed a number of specific membrane transporter genes that can characterize each segment. Among them, we examined expressions of the Na + -coupled cotransporters abundantly expressed in the second loop samples. Although the proximal II segment of the second loop is known for the elimination of excess solutes, the present results imply that the PII segment is also crucial for reabsorption of valuable solutes. Looking ahead to future studies, the segment-dependent gene expression profiling will be a powerful technique for unraveling the renal mechanisms and regulation in euryhaline elasmobranchs.

Factors influencing the sperm retrieval rate of microdissection testicular sperm extraction in patients with nonmosaic Klinefelter syndrome.

To investigate the factors affecting the sperm retrieval rate of microdissection testicular sperm extraction (micro-TESE) in patients with nonmosaic Klinefelter syndrome (KS), 64 patients with nonmosaic KS who underwent micro-TESE in the Center for Reproductive Medicine of Peking University Third Hospital (Beijing, China) between January 2016 and December 2017 were included in the study. Data on medical history, physical examination and laboratory examination results, and micro-TESE outcomes were collected. Patients were divided into two groups according to micro-TESE outcomes. The following factors were compared between the two groups by the Mann‒Whitney U test or Student's t-test based on the distribution (nonnormal or normal) of the factors: age, testicular size, follicle-stimulating hormone level, luteinizing hormone level, testosterone level, and anti-Müllerian hormone level. The overall success rate of sperm retrieval was 50.0%. Correlation analysis showed that testicular volume was positively correlated with testosterone level. Using a logistic regression model, age and anti-Müllerian hormone levels were found to be better predictors for the sperm retrieval rate than the other parameters.