Explore the vast range of titles available.

piRNAs are crucial for transposon silencing, germ cell maturation, and fertility in male mice. Here, we report on the genetic landscape of piRNA dysfunction in humans and present 39 infertile men carrying biallelic variants in 14 different piRNA pathway genes, including PIWIL1 , GTSF1 , GPAT2, MAEL, TDRD1 , and DDX4 . In some affected men, the testicular phenotypes differ from those of the respective knockout mice and range from complete germ cell loss to the production of a few morphologically abnormal sperm. A reduced number of pachytene piRNAs was detected in the testicular tissue of variant carriers, demonstrating impaired piRNA biogenesis. Furthermore, LINE1 expression in spermatogonia links impaired piRNA biogenesis to transposon de-silencing and serves to classify variants as functionally relevant. These results establish the disrupted piRNA pathway as a major cause of human spermatogenic failure and provide insights into transposon silencing in human male germ cells. piRNAs are small RNA molecules found primarily in the testes of mice and men. Stallmeyer et al. demonstrate that variants in specific genes can disrupt the formation of piRNAs, impairing spermatogenesis and causing human male infertility.

This article discusses the extensive use of publication counts as indicators of trends in the scientific activities of individual researchers, research groups, and entire disciplines. However, with the growing number of articles in general, these counts might produce false impressions among scientists. We propose a straightforward yet effective normalization method, which enables further context of publication counts by using a query and a reference term. Additionally, an open access implementation is readily available on the PubMed Normalization website.

From a biological and clinical perspective, it is imperative to establish primate spermatogonial cultures. Due to limited availability of human testicular tissues, the macaque (Macaca fascicularis) was employed as non-human primate model. The aim of this study was to characterize the expression of somatic as well as germ cell markers in testicular tissues and to establish macaque testicular primary cell cultures. Characterization of macaque testicular cell population was performed by immunohistochemical analyses for somatic cell markers (SOX9, VIM, SMA) as well as for germ cell markers (UTF1, MAGEA4, VASA). Testicular cells from adult macaque testes (n = 4) were isolated and cultured for 21 days using three stem cell culture media (SSC, PS and SM). An extended marker gene panel (SOX9, VIM, ACTA2; UTF1, FGFR3, MAGEA4, BOLL, DDX4) was then employed to assess the changes in gene expression levels and throughout the in vitro culture period. Dynamics of the spermatogonial population was further investigated by quantitative analysis of immunofluorescence-labeled MAGEA4-positive cells (n = 3). RNA expression analyses of cell cultures revealed that parallel to decreasing SOX9-expressing Sertoli cells, maintenance of VIM and ACTA2-expressing somatic cells was observed. Expression levels of germ cell marker genes UTF1, FGFR3 and MAGEA4 were maintained until day 14 in SSC and SM media. Findings from MAGEA4 immunofluorescence staining corroborate mRNA expression profiling and substantiate the overall maintenance of MAGEA4-positive pre- and early meiotic germ cells until day 14. Our findings demonstrate maintenance of macaque germ cell subpopulations in vitro. This study provides novel perspective and proof that macaques could be used as a research model for establishing in vitro germ cell-somatic cell cultures, to identify ideal culture conditions for long-term maintenance of primate germ cell subpopulation in vitro.

Homologous recombination rearranges genetic information during meiosis, creating new combinations of the genome while also introducing mutations, and influencing GC content. Here we report direct detection of recombination events using highly accurate long-read sequencing from testis tissue of 16 individuals across six primate species and three human sperm samples. Based on methylation patterns, we classify sequencing reads as originating from either somatic or germline cells. We identify 2881 crossovers, 2314 simple gene conversions, and 555 complex events, and analyze their chromosomal distribution. Crossovers are more telomeric, showing stronger concordance with recombination maps than gene conversions. Human samples align with a double-strand break map, whereas other species differ, consistent with variation in PRDM9-directed breaks, although the recombination process is otherwise conserved. Gene conversion tracts are short and of similar length across species (mean 22–95 bp), implying that most non-crossover events are undetectable. We observe GC-biased gene conversion for both single and multiple-SNV events, including sites flanking crossovers. We infer longer gene conversion tracts associated with crossovers (318–688 bp) than with non-crossovers. Highly accurate long-read sequencing combined with methylation-based classification of reads to specific cell types provides a powerful way of studying recombination events in single individuals of any mammalian species. Homologous recombination rearranges genetic information during meiosis to generate new combinations in the genome. Here, the authors report direct, single-individual detection of recombination in primates and humans using long-read sequencing.

This study characterized the failure rate of non-operative management (NOM) for complicated appendicitis (CA; perforation, abscess, phlegmon), and compared outcomes among patients undergoing acute appendectomy (AA), elective interval appendectomy (EIA), and unplanned appendectomy after failing to improve with NOM. Adults treated at one facility between 2007 and 2014 were retrospectively studied. Ninety-five patients presented with CA. Sixty individuals underwent AA. The remaining 35 patients initially underwent NOM: 14 underwent EIA, nine (25.7%) failed NOM, 12 never underwent surgery. All patients failing NOM had an open operation with most (55.6%) requiring bowel resection. AA and EIA were comparable in surgical approach, bowel resection and post-operative readmission. However, AA demonstrated a lower incidence of bowel resection (3.3% vs 17.1%, P = 0.048) when compared to all patients initially undergoing NOM. Due to the high incidence of failed NOM and the morbidity associated with failure, AA may be appropriate for CA. •Non-operative management failed in 25.7% of patients with complicated appendicitis.•Most patients who failed non-operative management required major bowel resection.•The incidence and morbidity of failed non-operative management favors acute surgery.

In eukaryotes, the nucleocytoplasmic export of bulk poly(A) + -mRNAs through the nuclear pore complex is mediated by the ubiquitously expressed NXT1-NXF1 heterodimer. In humans, NXT1 has an X-chromosomal paralog, NXT2 , which exhibits testis-enriched expression, suggesting a role in spermatogenesis. Here, we report the in vivo interaction of NXT2 with crucial components of the nuclear export machinery, including NXF1, the testis-specific NXF1 paralogs NXF2 and NXF3, and nuclear pore complex proteins. Binding to NXF2 and NXF3 is mediated by the NTF2-like domain of NXT2. By identifying infertile men with loss-of-function variants in NXT2 and NXF3 , we link the impaired NXT2-NXF activity to disturbed germ cell development. The predominant absence of germ cells in men with NXT2 deficiency indicates its critical function already during fetal or first steps of germ cell development. In contrast, loss of NXF3 affects later stages of spermatogenesis, resulting in quantitatively and qualitatively impaired sperm production. The study introduces NXT2 as a candidate gene for male infertility and shows that the encoded protein is involved in RNA nucleocytoplasmic transport in human testis by interacting with the RNA export factor NXF1 and proteins of the nuclear pore complex. NXT2 also interacts with the human testis-specific NXF1 paralogues NXF2 and NXF3. Mutations in NXT2 and NXF3 are linked to a disruption of nuclear export, leading to defective germ cell development and human male infertility.

Non-obstructive azoospermia, the absence of sperm in the ejaculate due to disturbed spermatogenesis, represents the most severe form of male infertility. De novo microdeletions of the Y-chromosomal AZFa region are one of few well-established genetic causes for NOA and are routinely analysed in the diagnostic workup of affected men. So far, it is unclear which of the three genes located in the AZFa chromosomal region is indispensible for germ cell maturation. Here we present four different likely pathogenic loss-of-function variants in the AZFa gene DDX3Y identified by analysing exome sequencing data of more than 1,600 infertile men. Three of the patients underwent testicular sperm extraction and revealed the typical AZFa testicular Sertoli cell-only phenotype. One of the variants was proven to be de novo. Consequently, DDX3Y represents the AZFa key spermatogenic factor and screening for variants in DDX3Y should be included in the diagnostic workflow. Analysing genetic data from 1,655 men with non-obstructive azoospermia (NOA) reveals four independent loss-of-function variants in DDX3Y , suggesting that it is a key gene in the AZFa region and should be considered in diagnostic workflows for NOA.

The majority of the US population live in urban areas, yet more than half of all trauma deaths occur in rural areas. The Rural Trauma Team Development Course (RTTDC) is developed to improve the outcomes of rural trauma and we aimed to study its effect on patient transfer. Trauma referrals 2 years before the RTTDC training were compared with referrals 2 years after the course. Of the 276 studied patients, 97 were referred before the RTTDC training and 179 patients were referred after the course. Transfer acceptance time was significantly shorter after the RTTDC training (139.2 ± 87.1 vs 110 ± 66.3 min, P = .003). The overall transfer time was also significantly reduced following the RTTDC training (257.4 ± 110.8 vs 219.2 ± 86.5 min, P = .002). Patients receiving pretransfer imaging had a significantly higher transfer time both before and after RTTDC training (all Ps < .01). Mortality was nearly halved (6.2% vs 3.4%) after the RTTDC training. The RTTDC training was associated with reduced transfer acceptance time and reduced transfer time. •In US, most people live in urban areas, yet more than half of all trauma deaths occur in rural areas.•The ACS Committee on Trauma developed the Rural Trauma Team Development Course (RTTDC).•RTTDC detects those requiring care at higher level trauma centers within 15 minutes.•We aimed to determine if RTTDC training is associated with early evaluation and transfer.•Transfer acceptance time was significantly shorter after the RTTDC training.•The overall transfer time was also significantly reduced following the RTTDC training.•Mortality was nearly halved after the RTTDC training.•RTTDC training was associated with reduced transfer acceptance time and shorter transfer time.

In mice the chemokine Cxcl12 and its receptor Cxcr4 participate in maintenance of the spermatogonial population during postnatal development. More complexity arises since Cxcl12 also binds to the non-classical/atypical chemokine receptor Cxcr7. We explored the expression pattern of Cxcl12, Cxcr4 and Cxcr7 during postnatal development in mouse testes and investigated the response of Cxcl12, Cxcr4, Cxcr7 and SSC-niche associated factors to busulfan-induced germ cell depletion and subsequent recovery by RNA expression analysis and localization of the proteins. In neonatal testes transcript levels of Cxcl12, Cxcr4 and Cxcr7 were relatively low and protein expression of Cxcr7 was restricted to gonocytes and spermatogonia. During development, RNA expression of Cxcl12 remained stable but that of Cxcr4 and Cxcr7 increased. Cxcr7 was expressed in germ cells located at the basement membrane of the seminiferous tubules. In adult testes, transcript levels of Cxcl12 were highest while the localization of Cxcr7 did not change. Following germ cell depletion, a significantly increased expression of Cxcl12 and a decreased expression of Cxcr7 were observed. Germ cells repopulating the seminiferous tubules were immunopositive for Cxcr7. We conclude that Cxcr7 expression to be restricted to premeiotic germ cells throughout postnatal testicular development and during testicular recovery. Hence, the spermatogonial population may not only be simply controlled by interaction of Cxcl12 with Cxcr4 but may also involve Cxcr7 as an important player.

Grafting of immature monkey testis tissue enables generation of sperm and offspring An increasing number of adult men face subfertility or even permanent infertility due to a loss of spermatogonial stem cells as a side effect of pediatric gonadotoxic treatments, including cancer therapies as well as treatments for benign sickle cell disease or thalassemia ( 1 , 2 ). Adult men can cryopreserve sperm as a fertility reserve, but prepubertal patients do not have this option. Removal and cryobanking of testicular tissue containing spermatogonia could offer a strategy to preserve the prepubertal individual's germline ( 1 ). Although cryobanking has started, there are currently no protocols available to derive sperm from the banked tissue. Advances in this research field are imperative. The primary treatment of severe male infertility is intracytoplasmic sperm injection (ICSI) into an oocyte. Although after its first description in 1992 the implications and risks associated with ICSI have been intensely debated, the technique has developed into a globally accepted therapy and has meanwhile led to the birth of hundreds of thousands of children ( 3 ). A major difference of ICSI to natural fertilization is that only a few spermatozoa are required to achieve successful fertilization. Therefore, even inefficient strategies to generate limited numbers of sperm allow treatment of male infertility. On page 1314 of this issue, Fayomi et al. ( 4 ) show that sperm isolated from grafted macaque testicular tissue fragments have the full potential to produce a healthy baby by using ICSI. Therefore, autografting of immature testicular tissue may become an option for human male fertility preservation.