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The notochord is a major regulator of embryonic patterning in vertebrates and abnormal notochordal development is associated with a variety of birth defects in man. Proper knowledge of the development of the human notochord, therefore, is important to understand the pathogenesis of these birth defects. Textbook descriptions vary significantly and seem to be derived from both human and animal data whereas the lack of references hampers verification of the presented data. Therefore, a verifiable and comprehensive description of the development of the human notochord is needed. Our analysis and three-dimensional (3D) reconstructions of 27 sectioned human embryos ranging from Carnegie Stage 8 to 15 (17-41 days of development), resulted in a comprehensive and verifiable new model of notochordal development. Subsequent to gastrulation, a transient group of cells briefly persists as the notochordal process which is incorporated into the endodermal roof of the gut while its dorsal side attaches to the developing neural tube. Then, the notochordal process embeds entirely into the endoderm, forming the epithelial notochordal plate, which remains intimately associated with the neural tube. Subsequently, the notochordal cells detach from the endoderm to form the definitive notochord, allowing the paired dorsal aortae to fuse between the notochord and the gut. We show that the formation of the notochordal process and plate proceeds in cranio-caudal direction. Moreover, in contrast to descriptions in the modern textbooks, we report that the formation of the definitive notochord in humans starts in the middle of the embryo, and proceeds in both cranial and caudal directions.

The detailed morphology of human development has intrigued scientists and the medical field alike. However, the scarcity of specimens hampers detailed mapping of tissue architecture. Furthermore, inaccuracies in the description of human development have crept into textbooks from observations of animal models that are extrapolated to humans. By mapping normal developmental processes and patterns, such as the growth and relative placement of organs, congenital anomalies can be better understood. de Bakker et al. generated interactive three-dimensional digital reconstructions based on the Carnegie collection of histologically sectioned human embryos spanning the first 2 months of gestation. These interactive models will serve as educational and scientific resources for normal and abnormal human development. Science , this issue p. 10.1126/science.aag0053 Interactive three-dimensional models unveil early human development. Current knowledge about human development is based on the description of a limited number of embryonic specimens published in original articles and textbooks, often more than 100 years ago. It is exceedingly difficult to verify this knowledge, given the restricted availability of human embryos. We created a three-dimensional digital atlas and database spanning the first 2 months of human development, based on analysis of nearly 15,000 histological sections of the renowned Carnegie Collection of human embryonic specimens. We identified and labeled up to 150 organs and structures per specimen and made three-dimensional models to quantify growth, establish changes in the position of organs, and clarify current ambiguities. The atlas provides an educational and reference resource for studies on early human development, growth, and congenital malformations.

Background In the Netherlands most patients are currently seen in an outpatient clinic after an anterior cervical discectomy, which is an effective neurosurgical procedure with relatively low rate of severe complications. In this back sight, the need for patients returning to the post-operative outpatient clinic could be questioned. The aim of the study is to evaluate whether a post-operative outpatient appointment after anterior cervical discectomy could be replaced by an alternative or be omitted without adversely impacting, or increasing, the value of healthcare and patient satisfaction for this procedure. Methods A narrative review was performed to evaluate the quality of care and patient satisfaction for patients with and without a post-operative outpatient appointment after spinal surgery. A literature search of the previous ten years was performed in Pubmed, CENTRAL and EMBASE. Results A total of 403 articles were identified. Four studies remained after title and abstract selection by 3 independent reviewers. No papers were selected for further analysis, due to the absence of interventional studies that compared the utility of a post-operative outpatient clinic appointment with an intervention after spinal surgery. Conclusions Currently, there is a lack of evidence for the need of a post-operative follow-up after anterior cervical discectomy. Nor is there any literature in favor of omitting these appointments. No determinants which patients benefits from these outpatient appointments could be identified. Potential harmful and beneficial effects of omitting these post-operative follow-ups should be investigated to identify possible determinant for patients who might benefit from a post-operative appointment.

Abstract Background The treatment of patients with symptomatic spinal metastasis is challenging, and it warrants a multi-disciplinary approach. When surgery is considered, the expected survival time at three months might be an important argument in the discussion. With the advent of new treatment modalities, however, validation of an existing prediction model is warranted. Methods Validation study with inclusion of patients after informed consent from May 2021 through December 2023 in one academic hospital and two large non-academic medical centers. Information was collected on the following variables: sex, primary tumor type, treatment of the primary tumor with curative intention, cervical location of the metastasis, and the highest Karnofsky Performance Score in 24 hours before presentation. The validation set included 378 patients with symptomatic spinal metastasis. The derivation set consisted of 567 patients. The main outcome are C-index, calibration slope, D-statistic, R2D, Brier score, joint test for misspecification Reults The model had a C-index value of 0.68 ± 0.02 (95% CI: 0.64–0.72). Calibration analysis yielded a calibration slope of 0.66 ± 0.09 (95% CI: 0.50–0.83). The D-statistic was 0.92, and the R2D value was 0.17. The model performed well, especially at three months, with a Brier score of 0.44. Although no mismatch was observed graphically, the joint test for misspecification yielded a statistically significant value. The model was therefore adjusted slightly, based on all 945 patients included in the original model and the current study. Conclusion The prediction model performed reasonably well in estimating survival at three months in patients with symptomatic spinal metastasis.

Initiation of antiretroviral therapy (ART) during primary HIV-1 infection (PHI) has been proposed to limit the formation of HIV-1 reservoirs. However, it remains unknown whether temporary ART initiated during PHI has a long-term effect on viral persistence. Here, we longitudinally quantify HIV-1 persistence markers and immunological parameters in the participants ( n  = 64) of a randomized controlled trial comparing 24 or 60 weeks of temporary ART vs. no treatment during PHI, who subsequently (re)initiated ART during chronic HIV-1 infection (CHI) after a median period of 116 weeks without treatment (ISRCTN59497461). Levels of several HIV-1 persistence markers (cell-associated unspliced RNA, total DNA, and intact DNA) do not significantly differ and strongly positively correlate between early and CHI ART periods in the same participants. Early ART is associated with lower HIV-1 proviral sequence diversity and superior restoration of the CD4/CD8 ratio, as well as lower levels of monocyte activation markers, compared to CHI ART, in the same participants. At CHI ART, intact HIV-1 DNA negatively correlates with HIV-specific T-cell responses. Finally, levels of HIV-1 persistence markers during CHI ART are lower in participants who had been pre-treated during PHI, indicating a long-term suppressive effect of temporary early ART on the persistence of HIV-1 reservoir. Initiating antiretroviral therapy (ART) during primary HIV-1 infection (PHI) may influence long-term viral persistence, yet its enduring effects remain unclear. Here, Pasternak and colleagues demonstrate that temporary ART started early in infection reduces HIV-1 proviral diversity and monocyte activation, and sustains lower levels of viral persistence markers, suggesting a lasting suppressive impact on the HIV-1 reservoir.

Antiretroviral therapy (ART) initiated in the acute phase of HIV infection (AHI) results in a smaller viral reservoir. However, the impact of early HIV-specific T-cell responses on long-term reservoir dynamics is less well characterized. Therefore, we measured the size of the viral reservoir and functionality of HIV-specific CD8+ T-cell responses after the acute phase at 24 and 156 weeks after ART initiation in people with HIV who started treatment during AHI. A significant reduction in total and defective HIV DNA and a trend toward a reduction in intact HIV DNA were observed between 24 and 156 weeks. Functional CD8+ T-cell responses against HIV peptides Env, Gag, Nef, and Pol were maintained over 3 years after treatment initiation. The proliferative capacity of HIV-specific CD8+ T-cells at 24 weeks of ART was predictive of the degree of reduction in total and defective HIV DNA between 24 and 156 weeks, suggesting HIV-specific CD8+ T-cells may at least partially drive the decline of the viral reservoir. Therefore, enforcing HIV-specific immune responses as early as possible after diagnosis of AHI should be a central focus of HIV cure strategies.

Antiretroviral therapy (ART) initiated in the acute phase of HIV infection (AHI) results in a smaller viral reservoir. However, the impact of early HIV-specific T-cell responses on long-term reservoir dynamics is less well characterized. Therefore, we measured the size of the viral reservoir and functionality of HIV-specific CD8+ T-cell responses after the acute phase at 24 and 156 weeks after ART initiation in people with HIV who started treatment during AHI. A significant reduction in total and defective HIV DNA and a trend toward a reduction in intact HIV DNA were observed between 24 and 156 weeks. Functional CD8+ T-cell responses against HIV peptides Env, Gag, Nef, and Pol were maintained over 3 years after treatment initiation. The proliferative capacity of HIV-specific CD8+ T-cells at 24 weeks of ART was predictive of the degree of reduction in total and defective HIV DNA between 24 and 156 weeks, suggesting HIV-specific CD8+ T-cells may at least partially drive the decline of the viral reservoir. Therefore, enforcing HIV-specific immune responses as early as possible after diagnosis of AHI should be a central focus of HIV cure strategies.

Antiretroviral therapy (ART) initiated in the acute phase of HIV infection (AHI) results in a smaller viral reservoir. However, the impact of early HIV-specific T-cell responses on long- term reservoir dynamics is less well characterized. Therefore, we measured the size of the viral reservoir and functionality of HIV-specific CD8+ T-cell responses after the acute phase at 24 and 156 weeks after ART initiation in individuals who started treatment during AHI. A significant reduction in total and defective HIV DNA and a trend towards a reduction in intact HIV DNA were observed between 24 and 156 weeks. Functional CD8+ T-cell responses against HIV peptides Env, Gag, Nef, and Pol were maintained over three years after treatment initiation. The proliferative capacity of HIV-specific CD8+ T cells at 24 weeks of ART was predictive of the degree of reduction in total and defective HIV DNA between 24 and 156 weeks, suggesting HIV-specific CD8+ T-cells may at least partially drive the decline of the viral reservoir. Therefore, enforcing HIV-specific immune responses as early as possible after diagnosis of AHI should be a central focus of HIV cure strategies.

Antiretroviral therapy (ART) initiated in the acute phase of HIV infection (AHI) results in a smaller viral reservoir. However, the impact of early HIV-specific T-cell responses on long-term reservoir dynamics is less well characterized. Therefore, we measured the size of the viral reservoir and functionality of HIV-specific CD8+ T-cell responses after the acute phase at 24 and 156 weeks after ART initiation in individuals who were diagnosed during AHI. A significant decline in total and defective HIV DNA and a trend towards a decline in intact HIV DNA were observed between 24 and 156 weeks. Functional CD8+ T-cell responses against HIV peptides Env, Gag, Nef, and Pol were maintained over three years after treatment initiation. The proliferative capacity of HIV-specific CD8+ T-cells at 24 weeks was associated with the decline of total and defective HIV DNA reservoir, suggesting that HIV-specific CD8+ T-cells may at least partially drive the decline of the viral reservoir. Therefore, enforcing HIV-specific immune responses as early as possible after diagnosis of AHI should be a central focus of HIV cure strategies.Competing Interest StatementThe authors have declared no competing interest.