[Clinical significance of monitoring NUP98::NSD1 fusion genes before and after allogeneic hematopoietic stem cell transplantation].

Objective: This study aimed to observe the dynamic changes of NUP98::NSD1 expression before and after allogeneic hematopoietic stem cell transplantation (allo-HSCT) . Moreover, the clinical value of measurable residual disease (MRD) was analyzed. Methods: Sixteen AML patients who were diagnosed with the NUP98::NSD1 fusion gene and received allo-HSCT at Peking University People's Hospital were included. The NUP98::NSD1 fusion gene and leukemia-associated immunophenotype (LAIP) were monitored before and after transplantation to evaluate their MRD status. Results: The median follow-up time for all patients was 526 days (139-1136 days) , with four patients (25.0%) experiencing hematological recurrence at a median of 474 days (283-607 days) after transplantation. Three patients (18.8%) died, two of whom (12.5%) died of leukemia recurrence. The median expression level of NUP98::NSD1 in newly diagnosed patients with complete data was 78.5% (18.9%-184.4%) at the time of initial diagnosis. The recurrence rate was higher in NUP98::NSD1-positive patients after transplantation, with 44.4% of patients experiencing recurrence, whereas no recurrence occurred in NUP98::NSD1-negative patients after transplantation. The area under the receiver operating characteristic curve predicted by the NUP98::NSD1 level after transplantation was 1.000 (95% confidence interval: 1.000-1.000, P=0.003) . Among the four patients with recurrence, NUP98::NSD1 was more sensitive than flow cytometry residual (FCM) and Wilms' tumor gene 1 (WT1) . Conclusions: The NUP98::NSD1 fusion gene can be used to evaluate the MRD status of allo-HSCT. NUP98::NSD1-positive patients after transplantation have a high relapse rate and poor prognosis. NUP98::NSD1 was more sensitive than FCM and WT1 in predicting posttransplant relapse.

Author Correction: Correlation between expression levels of lncRNA UCA1 and miR-18a with prognosis of hepatocellular cancer.

Correction to: European Review for Medical and Pharmacological Sciences 2020; 24 (7): 3586-3591-DOI: 10.26355/eurrev_202004_20820-PMID: 32329833, published online on 15 April 2020. After publication, the authors noticed some mistakes in the manuscript and applied to issue the following changes: the legend of Table I, the date of enrollment of the patients in the section titled "Baseline Characteristics of HCC Patients", the date of follow-up reported in the abstract and in the section entitled "Postoperative Follow-Up". The authors also applied to modify the survival curve of Figure 3 due to misuse of data in the statistical analysis. There are amendments to this paper. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/20820.

[Comparison of prognostic significance between multiparameter flow cytometry and real-time quantitative polymerase chain reaction in the detection of minimal residual disease of Philadelphia chromosome-positive acute B lymphocytic leukemia before allogeneic hematopoietic stem cell transplantation].

Objective: To explore the different values of minimal residual disease (MRD) detection by multiparameter flow cytometry (MFC) and real-time quantitative polymerase chain reaction (RQ-PCR) before hematopoietic stem cell transplantation (HSCT) for predicting relapse, leukemia-free survival (LFS) , and overall survival (OS) in Philadelphia chromosome-positive ALL (Ph(+) ALL) . Methods: A retrospective study (n=280) was performed. MRD was determined using multiparameter flow cytometry and RQ-PCR. Results: MRD analysis with MFC and RQ-PCR of the BCR-ABL fusion transcript showed a strong correlation before transplantation. The positive rates of MRD detected by MFC and RQ-PCR before transplantation were 25.7% (72/280) and 60.7% (170/280) , respectively. MFC MRD-positive (MRDpos) Ph(+) ALL patients had a higher 3 year cumulative incidences of relapse (CIR) than did MFC MRD-negative (MRDneg) Ph(+) ALL patients (23.6%vs 8.6%; P<0.001) . However, the RQ-PCR MRDpos group had similar rates of 3 year OS, LFS, and NRM compared with those in the RQ-PCR MRDneg group. Moreover, patients with RQ-PCR MRD ≥1% experienced higher 3 year CIR (23.1%vs 11.4%; P=0.032) , lower LFS (53.8%vs 74.4%; P=0.015) , and OS (57.7% vs 79.1%; P=0.009) compared with the RQ-PCR MRD<1% group. Multivariate analyses confirmed the association of MFC MRD status and RQ-PCR MRD ≥1% with outcomes (P<0.05) . The sensitivity, specificity, positive predictive value (PPV) , and negative predictive value (NPV) of MFC detection MRD to predict recurrence were 48.50%, 77.56%, 23.62%, and 87.16%, respectively. Moreover, the sensitivity, specificity, PPV, and NPV were 23.00%, 88.59%, 17.15%, and 91.84%, respectively, when RQ-PCR MRD ≥1% was used to predict recurrence. Additionally, the sensitivity, specificity, PPV, and NPV were 54.29%, 73.88%, 45.7% and 91.87%, respectively, when MRD-positive status before transplantation (MFC MRDpos or RQ-PCR MRD ≥1%) was used to predict recurrence after transplantation. Conclusions: Both MFC and RQ-PCR detection of pretransplant MRD levels can predict the prognosis of Ph(+) B-ALL patients receiving allogeneic HSCT. MFC MRD-positive status before transplantation is the risk factor of leukemia recurrence after transplantation. The combined use of the two methods (MFC MRDpos or RQ-PCR MRD ≥1%) can improve the sensitivity, PPV, and NPV of predicting recurrence and help to better screen high-risk patients for intervention, thereby improving clinical efficacy.

[Occurrence and related factors of preterm birth in Guangxi Zhuang Autonomous Region during 2017-2019].

Objective: To investigate the incidence of preterm birth in Guangxi Zhuang Autonomous Region and explore the related factors and their combined effects. Methods: The study subjects were women giving birth to live babies at the monitoring points of critical maternal hospital monitoring system in Guangxi Zhuang Autonomous Region from January 1, 2017 to December 31, 2019. The data of general characteristics (age and marital status), pregnancies (parity, number of previous cesarean delivery, the number of prenatal check and number of fetuses in this pregnancy) and disease conditions (placenta previa, placental abruption, hypertension, diabetes, anemia, and heart disease) were collected, and the incidence of preterm birth were calculated according to the definition of preterm birth set by WHO and China, respectively. Logistic regression model was used to explore the factors associated with premature birth and their combined effects. Results: According to definitions of WHO and China, the cumulative incidence of preterm birth in Guangxi from 2017 to 2019 was 7.45% (16 819/225 727) and 7.34% (16 559/225 727), respectively. Advanced age [≤34 years old as reference, OR (95%CI) of 35-39 and ≥40 years old were 1.36 (1.30-1.42) and 1.61 (1.50-1.74), respectively], unmarried (including divorced or widowed) [OR (95%CI): 1.28 (1.17-1.40)], primiparae [OR (95%CI): 1.34 (1.29-1.40)], previous cesarean section [no previous cesarean section as reference, OR (95%CI) of 1 and ≥2 times of previous cesarean section were 1.30 (1.24-1.36) and 1.85 (1.65-2.08), respectively], antenatal examination<8 [OR (95%CI): 2.72 (2.62-2.81)], multiple pregnancies [OR (95%CI): 15.00 (14.01-16.06)], placenta previa [OR (95%CI): 6.90 (6.35-7.50)], placental abruption [OR (95%CI): 8.18 (7.36-9.10)], gestational hypertension [OR (95%CI): 2.29 (2.17-2.42)], gestational diabetes mellitus [OR (95%CI): 1.43 (1.37-1.49)], anemia [OR (95%CI): 1.10 (1.07-1.14)], and heart diseases [OR (95%CI): 2.98(2.43-3.65)] were all positively correlated with preterm birth. The risk of preterm birth in pregnant women exposed to 1, 2, 3, 4, 5, 6 and ≥7 preterm birth related factors was 1.51, 2.29, 4.49, 9.69, 20.87, 46.88 and 192.11 times that of non-exposed women, respectively (all P values<0.001). Conclusion: Preterm birth is associated with maternal general characteristics, pregnancy and disease status, and the combined effect of preterm birth related factors significantly increases the risk of preterm birth.

Correlation between expression levels of lncRNA UCA1 and miR-18a with prognosis of hepatocellular cancer.

OBJECTIVE: To uncover the prognostic potentials of long non-coding RNA (lncRNA) UCA1 and miR-18a in hepatocellular cancer (HCC). PATIENTS AND METHODS: Expression levels of UCA1 and microRNA-18a (miR-18a) in HCC tissues and adjacent normal ones harvested from 55 HCC patients were determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Clinical data of HCC patients were recorded, including pathological grading, tumor staging, intrahepatic metastasis, serum level of α-fetoprotein (AFP), tumor size, tumor number, recurrence, etc. Based on the median levels of UCA1 and miR-18a, enrolled HCC patients were classified into high-level and low-level group. Potential correlation between expression levels of UCA1 and miR-18a with survival of HCC patients was analyzed. The 4-year follow-up data of HCC patients were collected for analyzing factors that may influence prognosis in HCC patients by the Cox regression model. RESULTS: UCA1 was upregulated and miR-18a was downregulated in HCC tissues. HCC patients with stage III-IV, tumor size ≥5 cm or multiple tumors expressed high level of UCA1. Besides, HCC patients with stage I-II, non-intrahepatic metastasis or primarily diagnosed expressed a relatively low level of miR-18a. High-level UCA1 and low-level miR-18a predicted worse prognosis in HCC patients. Cox regression analysis revealed that tumor node metastasis (TNM) staging, intrahepatic metastases, postoperative recurrences, and UCA1 were risk factors for HCC, while miR-18a was the protective factor. CONCLUSIONS: LncRNA UCA1 is upregulated and miR-18a is downregulated in HCC tissues. High-level UCA1 and low-level miR-18a are closely linked to poor prognosis in HCC.

[Success rate and influencing factors of external cephalic version for singleton pregnancies in the third trimester].

Objective: To investigate the factors associated with the success rate of external cephalic version (ECV) for singleton and non-cephalic presentation pregnancies in the third trimester. Methods: A retrospective study of ECV among singleton and non-cephalic presentation pregnant women in 36-40 weeks of gestation at Maternal and Child Health Hospital of Guangxi Zhuang Autonomous Region from January 2016 to June 2018 was analyzed. Results: (1) Totally, 251 cases of 358 pregnant women who underwent ECV were successful, with a total success rate of 70.1% (251/358). The success rate of multipara was 79.1% (129/163), while 62.6% (122/195) in primipara (P<0.01). The total vaginal delivery rate was 52.2% (187/358), the vaginal delivery rate of multipara was 61.3% (100/163), while 44.6% (87/195) in primipara (P<0.01). (2) Spontaneous reversion occurred in 7.6%(19/251) of ECV successful women, the rate of reversion of multipara was 10.9% (14/129), higher than that of the primipara [4.1% (5/122); P<0.01]. (3) Among the 232 pregnant women who did not reverted after successful ECV, 187 cases of successful vaginal delivery, the vaginal delivery rate was 80.6% (187/232); the vaginal delivery rate of the multipara was 87.0%(100/115), which was higher than that of the primipara [74.4%(87/117); P<0.01]. (4) The variables significantly associated with ECV success were parity, type of breech, whether fetal presentation was in pelvic or not (all P<0.05). The complication rate was 2.2% (8/358), among which the incidence of fetal distress, placental abruption and transient fetal heart abnormalities were 0.6% (2/358), 0.3% (1/358) and 1.4% (5/358) respectively. Conclusion: By close monitoring, ECV is a safe and effective procedure in selected appropriate cases, and worthy of clinical application.

Knockdown of IRE1α inhibits colonic tumorigenesis through decreasing ß-catenin and IRE1α targeting suppresses colon cancer cells.

The endoplasmic reticulum (ER) stress occurs frequently in cancers. The unfolded protein response (UPR) is activated to cope with ER stress. This has generated widespread interest in targeting UPR as therapeutic strategies. Inositol-requiring transmembrane kinase/endonuclease 1α (IRE1α), an ER stress sensor, is a key component of UPR. However, the role of IRE1α in tumorigenesis remains unclear. The purpose of this work is to investigate the role of IRE1α in colon cancer and to determine whether IRE1α could serve as a target for therapy. We found that knockdown of IRE1α suppressed the proliferation of colon cancer cells in vitro and xenograft growth in vivo. Inhibition of expression of IRE1α decreased stemness of colon cancer stem cells (CSCs) and attenuated growth of intestinal organoids. Genetic ablation of IRE1α prevented the colitis-associated colonic tumorigenesis in mice. The mechanistic study indicates that knockdown of IRE1α repressed the expression of ß-catenin, a key factor that drives colonic tumorigenesis, through activating pancreatic ER kinase/eukaryotic translation initiation factor 2α signaling. We found that the IRE1a-specific inhibitor 4µ8C could suppress the production of ß-catenin, inhibited the proliferation of colon cancer cells, repressed colon CSCs and prevented xenograft growth. The results suggest that IRE1α has a critical role in colonic tumorigenesis and IRE1α targeting might be a strategy for treatment of colon cancers.

Tunable diffraction-free array in nonlinear photonic crystal.

Diffraction-free beams have attracted increasing research interests because of their unique performances and broad applications in various fields. Although many methods have been developed to produce such beams, it is still challenging to realize a tunable non-diffracting beam. Here, we report the generation of a tunable diffraction-free array through second-harmonic generation in a nonlinear photonic crystal, i.e., a 2D periodically-poled LiTaO3 crystal. In such a crystal, the second-harmonic wave is engineered by properly designing the domain structure based on the Huygens-Fresnel principle. The characteristics of the generated diffraction-free array including its period, propagation length, and wavelength can be tuned by simply changing the input wavelength. Our observation not only enriches the diffraction-free optics, but also has potential applications for photolithography and imaging.

Pravastatin and C reactive protein modulate protease- activated receptor-1 expression in vitro blood platelets.

Protease-activated receptor-1 (PAR-1) plays an important role in mediating activation of human platelets by thrombin. However, mechanism of statin in ADP-induced platelet PAR-1 expression is also unknown. Aggregometry, flow cytometry, immunoblotting and ELISA were used to determine role of pravastatin participating in ADP-induced platelet activation and PAR-1 expression. ADP stimulation significantly increased PAR-1 expression on platelets. PAR-1 antagonist SCH-79797 inhibited platelet aggregation as well as decreased platelet P-selectin expression induced by ADP. CRP inhibited PAR-1 expression induced by ADP in a concentration-dependent manner. Pravastatin treatment reduced PAR-1 expression in a concentration-dependent manner. Combination treatment of CRP and Pravastatin significantly reduced platelet PAR-1 expression induced by ADP. By western-blot analysis, pravastatin treatment did not influence total PAR-1 after ADP treatment. CRP decreased platelet total PAR-1 expression induced by ADP. Pravastatin and CRP reduced TXB2 formation by ADP significantly. CRP decreased thrombin fragment F1+2 level with ADP treatment. Pravastatin, in contrast, did not influence F1+2 level. Upon treatment with Pravastatin reduced platelet LOX-1 expression induced by ADP. In conclusion, PAR-1 served as a critical mechanism to relay platelet activation process induced by ADP. CRP and pravastatin reduce PAR-1 expression in platelet by ADP pathway.

Polarization-free second-order nonlinear frequency conversion using the optical superlattice.

We propose a universal and practical scheme to realize polarization-free second-order nonlinear frequency-conversion processes, including sum-frequency generation, difference-frequency generation, and optical parametric amplification. This scheme is based on the optical superlattice with a noncritical phase-matching condition, which is suitable for optical integration. A chirped dual-period structure is proposed to ensure the efficiency and stability of the conversions.

Poling quality evaluation of optical superlattice using 2D Fourier transform method.

In this article we develop a method to evaluate the poling quality of optical superlattice (OSL) based on two-dimensional (2D) Fourier transform. To demonstrate this method, -Z or +Z face etched OSL samples with desired patterns are fabricated by standard electric field poling technique. By analyzing the processed micrograph of the etched surfaces, the magnitude of the reciprocal vectors of the OSL are calculated directly and rapidly. Second harmonic generation (SHG) experiment is performed to validate the evaluation result.

Frequency self-doubling optical parametric amplification: noncollinear red-green-blue light-source generation based on a hexagonally poled lithium tantalate.

Simultaneous generation of noncollinear red, green, and blue light from a single hexagonally poled lithium tantalate is reported. It results from the frequency self-doubling optical parametric amplification process, a process of second-order harmonic generation cascaded optical parametric amplification in a single-pass setup. The temperature and spectrum detuning characters of each cascaded quasi-phase-matching process are studied. This unique red-green-blue light source has potential applications in laser display and other laser industries.

Ethanol-induced neuronal apoptosis in vivo requires BAX in the developing mouse brain.

A single episode of ethanol intoxication triggers widespread apoptotic neurodegeneration in the infant rat or mouse brain. The cell death process occurs over a 6-16 h period following ethanol administration, is accompanied by a robust display of caspase-3 enzyme activation, and meets ultrastructural criteria for apoptosis. Two apoptotic pathways (intrinsic and extrinsic) have been described, either of which may culminate in the activation of caspase-3. The intrinsic pathway is regulated by Bax and Bcl-XL and involves Bax-induced mitochondrial dysfunction and release of cytochrome c as antecedent events leading to caspase-3 activation. Activation of caspase-8 is a key event preceding caspase-3 activation in the extrinsic pathway. In the present study, following ethanol administration to infant mice, we found no change in activated caspase-8, which suggests that the extrinsic pathway is not involved in ethanol-induced apoptosis. We also found that ethanol triggers robust caspase-3 activation and apoptotic neurodegeneration in C57BL/6 wildtype mice, but induces neither phenomenon in homozygous Bax-deficient mice. Therefore, it appears that ethanol-induced neuroapoptosis is an intrinsic pathway-mediated phenomenon involving Bax-induced disruption of mitochondrial membranes and cytochrome c release as early events leading to caspase-3 activation.

Apoptosis in the in vivo mammalian forebrain.

Apoptosis is a word originally introduced by Kerr, Wyllie, and colleagues for a cell death process they defined in terms of its ultrastructural appearance in nonneuronal cells from various tissues. There are very few studies providing detailed ultrastructural criteria for recognizing neuronal apoptosis in the in vivo mammalian brain. In the absence of such criteria, the Kerr/Wyllie description pertaining to nonneuronal cells has served as a reference standard. However, contemporary neurobiologists typically rely on cell culture models for studying neuronal apoptosis, and these models are rarely validated ultrastructurally; rather they are assumed to be appropriate models based on unvalidated biochemical tests for apoptosis. Relying on evidence generated in such cell culture models or on nonspecific cytochemical tests applied to brain tissue, many authors have recently suggested that an apoptotic mechanism may mediate neuronal death in a wide variety of human neurodegenerative diseases. Whether the cell death process in neurodegenerative diseases meets ultrastructural criteria for apoptosis has been given very little consideration. Recently, several methods have been described for triggering extensive apoptotic neurodegeneration in the developing in vivo mammalian brain. These methods include head trauma or treatment with several types of drugs (NMDA antagonists, GABAA agonists, or ethanol). We have performed an ultrastructural analysis of the neuronal cell death process triggered in the cerebral cortex and thalamus by these several methods and compared it with physiological cell death (PCD), a prototypic example of neuronal apoptosis that occurs naturally in the developing brain. Our findings, which are reviewed herein, demonstrate that the types and sequence of changes induced by each of the above methods are identical to those that characterize PCD. This confirms that each of these methods produces bona fide in vivo apoptotic neurodegeneration, and it signifies that our description of this neuronal apoptotic process, which differs in some respects from the Kerr/Wyllie description of nonneuronal apoptosis, can serve as a useful reference standard for recognizing the characteristic changes that in vivo neurons undergo when they are dying by an apoptotic mechanism.

Crucial effects of coupling coefficients on quasi-phase-matched harmonic generation in an optical superlattice.

Coupling of optical parametric processes in an optical superlattice through quadratic nonlinearity was analyzed theoretically. Solving the coupled equations, we found that efficient quasi-phase-matched third-harmonic (TH) generation depends not only on the magnitude of the coupling coefficients but also on their ratio. Theoretically, all the fundamental energy can be transferred to the TH at a particular ratio. In other cases, there exists an optimum condition that corresponds to a maximum TH conversion efficiency. The result is of practical importance for the design of TH devices.

Early development and developmental plasticity of the fasciculus gracilis in the North American opossum (Didelphis virginiana).

The first objective of the present study was to ask when axons of the fasciculus gracilis reach the nucleus gracilis in the North American opossum (Didelphis virginiana). When Fast Blue (FB) was injected into the lumbar cord on postnatal day (PD) 1 and the pups were killed 2 days later, labeled axons were present within a distinct fasciculus gracilis at thoracic and cervical levels of the cord. When comparable injections were made at PD3 or 5 and the pups were allowed to survive for the same time period, a few labeled axons could be followed to the caudal medulla where they were located dorsal to the presumptive nucleus gracilis. In order to verify these observations and to determine if any of the axons which innervate the nucleus gracilis early in development originate within dorsal root ganglia, we also employed cholera toxin conjugated to horseradish peroxidase (CT-HRP) to label dorsal root axons transganglionically. When CT-HRP was injected into the hindlimb on PD1 and the pups were maintained for 1 day prior to death and HRP histochemistry, labeled axons were present within the fasciculus gracilis at thoracic and cervical levels, but they could not be traced into the medulla. When comparable injections were made on PD3, and the pups were maintained for 2 days, labeled axons were present within the caudal medulla. Our second objective was to determine whether axons of the fasciculus gracilis grow through a lesion of their spinal pathway during early development. In one group of animals, the thoracic cord was transected at PD5, 8, 12, 20 and 26 and bilateral injections of Fast Blue (FB) were made four segments caudal to the lesion 30-40 days later. After a 3-5 day survival, the pups were killed and perfused so that the spinal cord and brainstem could be removed and sectioned for fluorescence microscopy. In all of the cases lesioned at PD5, axons of the fasciculus gracilis were labeled rostral to the site of transection and they could be followed to the nucleus gracilis. Evidence for growth of fasciculus gracilis axons into the caudal medulla was also seen in cases lesioned at PD8. In contrast, labeled axons were not observed rostral to the lesion when it was made at PD12 or at later stages of development. In order to verify that some of the axons which crossed the lesion originated within dorsal root ganglia, the thoracic cord was transected at PD5 in another group of animals and 7 days later, injections of CT-HRP were made into one of the hindlimbs. After a 3 day survival, labeled axons could be traced through the lesion site and into the caudal medulla. We conclude that axons of the fasciculus gracilis reach the nucleus gracilis by at least PD5 in the opossum and that they grow through a lesion of their spinal pathway when it is made at the same age or shortly thereafter. The critical period for such growth appears to end between PD8 and PD12.

Developmental plasticity of reticulospinal and vestibulospinal axons in the north American opossum, Didelphis virginiana.

We have shown previously that rubral axons grow around a lesion of their spinal pathway in the North American opossum if it is made at early stages of development. In the present experiments, we have asked whether reticular and vestibular axons have the same ability. The spinal cord was hemisected at postnatal day 20, 12, or 5, well within the critical period for rubrospinal plasticity, and, approximately 30 days later, bilateral injections of fast blue were made about four segments caudal to the lesion. The pups were killed 4 or 5 days after the injections. In most of the animals lesioned on postnatal day 20, labeled neurons were not found in the medial part of the pontine reticular nucleus or the dorsal part of the lateral vestibular nucleus ipsilateral to the lesion. The spinal projections from both areas are exclusively ipsilateral. When the lesions were made at postnatal day 12 or 5, however, labeled neurons were present in both areas, suggesting that they supported axons that had grown caudal to the lesion. As was expected from previous studies, rubral neurons were labeled contralateral to the lesion in all three groups. In the opossum, as in other species, the red nucleus projects contralaterally. We conclude that reticular and vestibular axons, like axons from the red nucleus, grow around a lesion of their pathway during development and that the critical period for their plasticity ends earlier than that for rubrospinal axons.

The early development of major projections from caudal levels of the spinal cord to the brainstem and cerebellum in the gray short-tailed Brazilian opossum, Monodelphis domestica.

The Brazilian short-tailed opossum, Monodelphis domestica, is born 14-15 days after copulation and is available for experimentation at stages of development corresponding to those which occur in utero in placental mammals. In the present study, we took advantage of the opossum's embryology to study the development of projections from caudal levels of the spinal cord to the brainstem and cerebellum using axonal tracing methods. In all cases, a 2-3 day survival time was used for axonal transport. When injections of Fast blue (FB) were made into caudal levels of the thoracic cord at postnatal day (PD) 1 or 2, axonal labeling could not be identified at supraspinal levels. When injections were made at PD3, however, labeled axons were found in the fasciculus gracilis at caudal medullary levels, within the ventrolateral medulla and pons, within an incipient inferior cerebellar peduncle, and within the cerebellar anlage. The dorsal root origin of at least some of the axons within the fasciculus gracilis was evidenced by the transganglionic transport of cholera toxin conjugated to horseradish peroxidase from the hindlimbs. After FB injections at PD7, a few labeled axons could be traced from the fasciculus gracilis into the nucleus gracilis and from the ventrolateral pathway to the inferior olive. Generally comparable results were obtained using wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP). In cases injected with FB at PD9, the pattern of brainstem labeling was adult-like. Although labeled axons were present within the cerebellum of animals injected with FB on PD3, they were limited to the marginal zone. Axonal labeling was present within an identifiable internal granular layer in cases injected with either FB or WGA-HRP at PD16, and it appeared to be limited to specific bands which foreshadowed those seen at later stages of development and in the adult animal. In some cases, labeled axons were present within the molecular layer where they were not seen in the adult animal. Our results provide a timetable for the normal development of projections from caudal levels of the spinal cord to the brainstem and cerebellum in Monodelphis and show that such development occurs postnatally rather than prenatally, as in placental mammals.