An engineered citrus tristeza virus (T36CA)-based vector induces gene-specific RNA silencing and is graft transmissible to commercial citrus varieties.

A protein-expressing citrus tristeza virus (CTV)-based vector construct, pT36CA-V1.3, obtained from a California isolate of the T36 strain (T36CA), was retooled into a virus induced gene silencing (VIGS) system intended for use with studies of California citrus. VIGS constructs engineered with a truncated Citrus macrophylla (Cm) PHYTOENE DESATURASE (PDS) gene sequence in the sense or anti-sense orientation worked equally well to silence the endogenous CmPDS gene. In a parallel effort to optimize vector performance, two non-synonymous nucleotides in open reading frame 1a of pT36CA-V1.3 were replaced with those conserved in the reference sequences from the T36CA cDNA library. The resulting viruses, T36CA-V1.4 (with one amino acid modification: D760N) and T36CA-V1.5 (with two amino acid modifications: D760N and P1174L), along with T36CA-V1.3 were individually propagated in Nicotiana benthamiana and C. macrophylla plants. Enzyme-linked immunosorbent assay (ELISA) measurements of extracts of the newly emerged leaves suggested that all three viruses accumulated to similar levels in N. benthamiana plants at 5 week-post-inoculation. ELISA values of T36CA-V1.4- and -V1.5-infected C. macrophylla samples were significantly higher than that of T36CA-V1.3-infected samples within an 8 to 12 month-post-inoculation (mpi) window, suggesting a higher accumulation of T36CA-V1.4 and -V1.5 than T36CA-V1.3. However, at 36 mpi, the ELISA values suggested that all three viruses accumulated to similar levels. When C. macrophylla plants infected with each of the three viruses were grafted to commercial citrus varieties, a limited number of receptor plants became infected, demonstrating a weak but nonetheless (the first) successful delivery of T36CA to California-grown commercial citrus.

Compost Filling Methods Affect Green Mold Disease Incidence in Commercial Mushrooms.

Green mold (Trichoderma aggressivum) is an invasive disease of commercial mushrooms introduced into the United States from Europe that now has spread to commercial mushrooms throughout North America. We examined potential sources of invasive green mold inoculum and the association with different compost filling technologies on a large actively producing commercial mushroom farm. Green mold foci were sampled bed by bed, which generated 20,906 data points. Logistic regression was used to determine treatment differences. Mechanical filling of compost into the beds reduced green mold incidence over hand filling, apparently due to the reduced incidence of worker contact with the floor and between beds. Lower growing beds located closer to the floor had a higher incidence of green mold for both mechanical and hand-filled beds. We conclude that mechanical filling and generally reducing contact with the floor and between beds will reduce spread of green mold in commercial mushroom production.

The Effectiveness of Cognitive-Behavioral Therapy in Helping People on Sick Leave to Return to Work: A Systematic Review and Meta-analysis.

PURPOSE: Previous research has systematically studied the effectiveness of Cognitive Behavioral Therapy (CBT)-based interventions in managing both mental and physical symptoms of chronic disease including depression, stress-related mental disorders (SMD), and chronic pain that are common causes of sick leave. However, a systematic review focusing on the effectiveness of CBT in facilitating RTW is lacking. This study compiles research on utilizing CBT-based interventions for helping employees on sick leave return to work. METHODS: Randomized controlled trials (RCT) published between 1 January 1990 and 27 June 2022 were searched in MEDLINE, EMBASE, The Cochrane Library, Scopus, PsycINFO, Web of Science, and PubMed. The primary outcome variables included a return to work (RTW) measure and sickness absences. The secondary outcomes include psychological conditions (mental illness, stress, anxiety, and depression) and physical condition (working ability, fatigue, and physical function). RESULTS: Thirty-four RCTs were included in the analysis. Fifteen RCTs with 1727 participants reported on sick leave. Results showed that participants who completed CBT intervention had reduced sick leave in days (mean reduction - 3.654; 95%CI - 5.253, - 2.046; p < 0.001) compared to the control group. Sixteen papers with 2298 participants reported that the intervention group RTW 1.5 days earlier (95%CI 1.019, 1.722; p < 0.05). CBT-based interventions were effective in managing fatigue, mental illness, and depression, and improving physical function while it showed no effects in managing stress, anxiety and working ability. CONCLUSIONS: The findings indicate that CBT-based interventions are effective in reducing the length of sick leave and facilitating the RTW of employees in the intervention group.

Adaptation of feeding behaviors on two Brassica species by colonizing and noncolonizing Bemisia tabaci (Hemiptera: Aleyrodidae) NW whiteflies.

Bemisia tabaci New World (NW) (Gennadius) (Hemiptera: Aleyrodidae), a whitefly in the B. tabaci species complex, is polyphagous on many plant species. Yet, it has been displaced, albeit not entirely, by other whitefly species. Potential causes could include issues with adaptation, feeding, and the colonization of new-hosts; however, insights that would help clarify these possibilities are lacking. Here, we sought to address these gaps by performing electropenetrography (EPG) recordings of NW whiteflies, designated "Napus" and "Rapa," reared on 2 colony hosts, Brassica napus and B. rapa, respectively. Analysis of 17 probing and pathway (pw) phase-related EPG variables revealed that the whiteflies exhibited unique probing behaviors on their respective colony hosts, with some deterrence being encountered on B. rapa. Upon switching to B. rapa and B. napus, the probing patterns of Napus and Rapa whiteflies, respectively, adapted quickly to these new-hosts to resemble that of whiteflies feeding on their colony hosts. Results for 3 of the EPG variables suggested that B. rapa's deterrence against Napus whitefly was significant prior to the phloem phase. This also suggested that adaptation by Rapa whitefly improved its pw probing on B. rapa. Based on analysis of 24 phloem phase-related EPG variables, Napus and Rapa whiteflies performed equally well once they entered phloem phase and exhibited comparable phloem acceptability on both the colony- and new-hosts. These findings demonstrate that NW whiteflies reared on a colony host are highly adaptable to feeding on a new host despite encountering some deterrence during the nonphloem phases in B. rapa plant.

Differential Activity-Dependent Increase in Synaptic Inhibition and Parvalbumin Interneuron Recruitment in Dentate Granule Cells and Semilunar Granule Cells.

Strong inhibitory synaptic gating of dentate gyrus granule cells (GCs), attributed largely to fast-spiking parvalbumin interneurons (PV-INs), is essential to maintain sparse network activity needed for dentate dependent behaviors. However, the contribution of PV-INs to basal and input-driven sustained synaptic inhibition in GCs and semilunar granule cells (SGCs), a sparse morphologically distinct dentate projection neuron subtype, is currently unknown. In studies conducted in hippocampal slices from mice, we find that although basal IPSCs are more frequent in SGCs and optical activation of PV-INs reliably elicited IPSCs in both GCs and SGCs, optical suppression of PV-INs failed to reduce IPSC frequency in either cell type. Amplitude and kinetics of IPSCs evoked by perforant path (PP) activation were not different between GCs and SGCs. However, the robust increase in sustained polysynaptic IPSCs elicited by paired afferent stimulation was lower in SGCs than in simultaneously recorded GCs. Optical suppression of PV-IN selectively reduced sustained IPSCs in SGCs but not in GCs. These results demonstrate that PV-INs, while contributing minimally to basal synaptic inhibition in both GCs and SGCs in slices, mediate sustained feedback inhibition selectively in SGCs. The temporally selective blunting of activity-driven sustained inhibitory gating of SGCs could support their preferential and persistent recruitment during behavioral tasks.SIGNIFICANCE STATEMENT Our study identifies that feedback inhibitory regulation of dentate semilunar granule cells (SGCs), a sparse and functionally distinct class of projection neurons, differs from that of the classical projection neurons, GCs. Notably, we demonstrate relatively lower activity-dependent increase in sustained feedback inhibitory synaptic inputs to SGCs when compared with GCs which would facilitate their persistent activity and preferential recruitment as part of memory ensembles. Since dentate GC activity levels during memory processing are heavily shaped by basal and feedback inhibition, the fundamental differences in basal and evoked sustained inhibition between SGCs and GCs characterized here provide a framework to reorganize current understanding of the dentate circuit processing.

Developmental changes in structural and functional properties of hippocampal AMPARs parallels the emergence of deliberative spatial navigation in juvenile rats.

The neural mechanisms that support the late postnatal development of spatial navigation are currently unknown. We investigated this in rats and found that an increase in the duration of AMPAR-mediated synaptic responses in the hippocampus was related to the emergence of spatial navigation. More specifically, spontaneous alternation rate, a behavioral indicator of hippocampal integrity, increased at the end of the third postnatal week in association with increases in AMPAR response duration at SC-CA1 synapses and synaptically driven postsynaptic discharge of CA1 pyramidal neurons. Pharmacological prolongation of glutamatergic synaptic transmission in juveniles increased the spontaneous alternation rate and CA1 postsynaptic discharge and reduced the threshold for the induction of activity-dependent synaptic plasticity at SC-CA1 synapses. A decrease in GluA1 and increases in GluA3 subunit and transmembrane AMPAR regulatory protein (TARP) expression at the end of the third postnatal week provide a molecular explanation for the increase in AMPAR response duration and reduced efficacy of AMPAR modulators with increasing age. A shift in the composition of AMPARs and increased association with AMPAR protein complex accessory proteins at the end of the third postnatal week likely "turns on" the hippocampus by increasing AMPAR response duration and postsynaptic excitability and reducing the threshold for activity-dependent synaptic potentiation.

Tessellated fundus occurs earlier than myopia in children aged 3-6 years.

BACKGROUND/OBJECTIVES: Tessellated fundus can exist in normal healthy eyes. This study aims to evaluate the occurrence and influencing factors of tessellated fundus in preschool children aged 3-6 years. SUBJECTS/METHODS: This kindergarten-based cross-sectional study included 1716 children with an age range of 3-6 years. All participants underwent a comprehensive eye examination and a questionnaire. According to the number of quadrants occupied by tessellated fundus around the optic disc in fundus photographs, it was divided into four grades. RESULTS: 600 (35.0%) children had peripapillary tessellation. According to the spherical equivalent (SE), the subjects were divided into three groups: Hyperopia group (SE > + 0.75D, n = 1194)；Pre-myopia group (-0.50D < SE ≤ + 0.75D, n = 455); Myopia group (SE ≤ -0.50D, n = 67). The proportion of peripapillary tessellated fundus was 33.0%, 38.0%, 50.7% respectively. According to the regression analysis, in the non-myopia group (Pre-myopia group and Hyperopia group), the occurrence of peripapillary tessellated fundus was associated with longer axial length (OR, 1.566; 95% CI: 1.229-1.996, p < 0.001) and larger corneal radius of curvature (OR, 1.837; 95% CI: 1.006-3.354, p = 0.048). However, in Pre-myopia group, the corneal radius of curvature was not associated with the occurrence of peripapillary tessellated fundus (p = 0.830). In Hyperopia group, the corneal radius of curvature was associated with the occurrence of peripapillary tessellated fundus (OR, 2.438; 95% CI: 1.160-5.122, p = 0.019). CONCLUSIONS: The occurrence of peripapillary tessellated fundus is more than 30% in 3-6 year old preschool children. Tessellated fundus can also occur in non-myopic children, and is related to the length of axial length and large radius of corneal curvature.

Temporal vascular arcade angle in fundus image was associated with the rate of spherical equivalent refractive error and axial length changes in myopia children with young school age.

PURPOSE: To evaluate temporal vascular arcade angle and its influencing factors in myopic children. METHODS: It was a retrospective study, we reviewed the records of 119 patients aged 6-10 years with myopia (spherical equivalent refractive error (SER) ≤ -0.05D) in the third year of follow-up in Beijing Hyperopia Reserve Research. We measured temporal vascular arcade angles on the fundus photographs and measured 3-year rate of spherical equivalent(D/year) and axial length (AXL) changes(mm/year). RESULTS: Mean age at initial visit was 7.71±1.20 years and mean SER was -1.32±1.09D. Children were divided into two groups according to the refractive status of children at baseline: Myopia onset group (SER>-0.50D at baseline) (n = 107) and Myopia progression group (SER≤-0.50D at baseline) (n = 12). The mean SER in Myopia progression group was much smaller than Myopia onset group (P < 0.001) and mean AXL in Myopia progression group was much longer than Myopia onset group (P = 0.042). AXL (r=-0.320, P < 0.001), SER change rate (r=-0.209, P = 0.022) and AXL change rate (r=-0.232, P = 0.011) were associated with temporal vascular arcade angle in all participants. In Myopia onset group, AXL (r=-0.317, P < 0.001) and AXL change rate (r=-0.190, P = 0.05) were associated with temporal vascular arcade angle. There were no parameters were associated with temporal vascular arcade angle (all P > 0.05) in Myopia progression group. Only AXL (r=-0.306, P = 0.018) was associated with temporal vascular arcade angle in girls while AXL (r=-0.370, P = 0.004), SER change rate (r=-0.317, P = 0.013) and AXL change rate (r=-0.365, P = 0.004) were all associated with the Angle in boys. CONCLUSION: Temporal vascular arcade angle was associated with the rate of SER and AXL changes in myopia onset children, and showed gender differences. These may suggest that lamina cribrosa location has different influencing factors in different genders and different stages of myopia development. Due to the small number of people in Myopia progression group, large sample size studies are still needed in the future.

Relationship between the length of macular Bruch's membrane on fundus photograph and myopia occurrence in pre-myopia children aged 3-6 years: A 3-year longitudinal study.

PURPOSE: To evaluate the occurrence and influencing factors of myopia occurrence in pre-myopia children aged 3-6 years. METHODS: This study included 204 pre-myopia (-0.50D-0.50D). The length of macular BM was shorter in Myopia group than that in Non-myopia group (P < 0.001). Baseline SE and the length of macular BM were independent influencing factors which associated with myopia occurrence (OR, 0.031; 95 % CI, 0.008-0.117, P < 0.001 and OR, 0.204; 95 % CI, 0.055-0.763, P = 0.018, respectively) by multivariate binary logistic regression analysis. SE changing process represented the changes of SE, Myopia group had bigger SE changes (P < 0.001). And in the multivariate liner regression analysis, age was the common influencing factor of SE changing process in total participants, Non-myopia group and Myopia group (B = 0.234, P < 0.001; B = 0.078, P = 0.010; B = 0.161, P = 0.046, respectively) CONCLUSIONS: Initial SE and the length of macular BM in pre-myopia children aged 3-6 years were the independent factors of the occurrence of myopia. And initial age was the common factor that associated with SE changing process.

The determinants of growth failure in children under five in 25 low- and middle-income countries.

Background: Past studies have identified determinants of growth failure (GF) such as socio-economic, nutritional, parenting, and inequality factors. However, few studies investigate the numerous causes of GF across multiple countries. By analysing the data of children under five in 25 low and middle-income countries, this study aims to examine the correlations of determinants with GF to identify the strongest modifiable risk factors. Methods: Cross-sectional study design was used, and data were collected across 25 LMICs by the United Nations Children's Fund in 2019. Regions and households were randomly selected in participating LMICs. The four outcome measures were stunting, wasting, underweight and low body mass index (BMI). Results: Multilevel analysis was performed to identify the impact of country, suburb, and household levels on the variance of outcome variables. GF measures were significantly correlated with low gross domestic product (GDP) per capita (odds ratio (OR) = 2.482), rural areas (OR = 1.223), lack of health insurance (OR = 1.474), low maternal education (OR = 2.260), lack of plain water (OR = 1.402), poor maternal physical caregiving ability (OR = 1.112), low carbohydrate consumption (OR = 1.470), and continued breastfeeding in children >12 months old (OR = 0.802). Conclusions: By identifying key GF risk factors, this study may provide valuable insights for policymaking and interventions. This may allow the prioritisation of resources within countries for preventative measures to be developed.

Effectiveness of telemonitoring intervention on glycaemic control in patients with type 2 diabetes mellitus: A systematic review and meta-analysis.

BACKGROUND: Type 2 diabetes mellitus (T2DM) is a rising global health concern that requires long-term treatment and close monitoring. Telemonitoring has been shown to be a promising tool to facilitate patient-physician interaction and improve glycaemic control. METHOD: Randomised controlled trials (RCT) of telemonitoring in T2DM published between 1990 and 2021 were searched through multiple electronic databases. The primary outcome variables included HbA1c and fasting blood glucose (FBG), and BMI was a secondary outcome variable. RESULTS: Thirty RCT with a total of 4,678 participants were included in this study. Twenty-six studies reported on HbA1c, which was shown to be significantly lower in participants on telemonitoring when compared to conventional care. Ten studies investigated FBG which collectively showed no statistically significant difference. Subgroup analysis demonstrated the effect of telemonitoring on glycaemic control is influenced by a range of factors concerning system practicality, user engagement, patient characteristics and disease education. CONCLUSION: Telemonitoring exhibited a great potential to improve T2DM management. Several technical features and patient factors may influence the effectiveness of telemonitoring. Further studies are needed to verify the findings and address limitations before its implementation into routine practice.

Synergistic effects of miR-708-5p and miR-708-3p accelerate the progression of osteoporosis.

BACKGROUND: Bone homeostasis is a tightly orchestrated process maintained by osteoblasts and osteoclasts, and a disruption of their steady-state equilibrium can lead to the occurrence of osteoporosis (OP). METHODS: We investigated the differential expression of micro (mi)RNAs in the bone tissues of a postmenopausal osteoporosis rat model induced by ovariectomy (OVX). Real-time PCR was used to verify the differentially expressed miRNAs in bone samples from OP patients and controls. The specific targets of two differentially expressed miRNAs in osteogenic or osteoclast differentiation were determined by bioinformatic prediction, and mRNA and protein detection. RESULTS: miR-708-5p and miR-708-3p were highly expressed in the bone tissue of OVX rats and OP patients. miR-708-5p negatively regulated osteoblast differentiation in bone marrow mesenchymal stem cells by targeting SMAD specific E3 ubiquitin protein ligase 2, while miR-708-3p positively regulated osteoclast differentiation in bone marrow monocytes by targeting cerebellar degeneration associated protein 1 antisense RNA. miR-708-5p and miR-708-3p were shown to originate from the same precursor miRNA and to have a synergistic effect on the development of osteoporosis with different temporal and spatial patterns. CONCLUSION: Our findings provide a referential theoretical basis and targets for the prevention and treatment of osteoporosis.

[Association between TGF-Beta1 in allograft and chronic allograft nephropathy].

OBJECTIVE: To investigate the relation between TGF-beta1 in allograft and chronic allograft nephropathy (CAN). METHODS: The levels of urine TGF-beta1 were tested in 146 recipients whose renal function were normal from September 1, 2000 to January 31, 2001. Twenty recipients with the highest level of urine TGF-beta1 were classified in group A, while 20 other recipients with the lowest level of urine TGF-beta1 were classified in group B. In these two groups biopsies were carried out in 14 cases and 12 cases respectively, and TGF-beta1 mRNA in the biopsies was measured by RT-PCR. The levels of TGF-beta1 in the blood were also measured in the two groups. Three years later, the renal function was compared between the two groups. Biopsies were carried out in renal recipients whose creatinine is higher than normal. RESULTS: The level of TGF-beta1 in the blood showed no significant difference between the two groups; 3 years after transplantation, the loss of renal function in group A was severer than that in group B. The number levels of CAN cases in group A was larger than that in group B. The expression levels of TGF-beta1 and TGF-beta1 mRNA of the allografts were higher in group A than in group B; there were statistically significant differences between the two groups. CONCLUSION: The findings suggest that there is an association between TGF-beta1 in kidneys and CAN. The level of urine TGF-beta1 after renal transplantation may predict future renal function.

Calcineurin inhibitor-free CD28 blockade-based protocol protects allogeneic islets in nonhuman primates.

Recent success using a steroid-free immunosuppressive regimen has renewed enthusiasm for the use of islet transplantation to treat diabetes. Toxicities associated with the continued use of a calcineurin inhibitor may limit the wide-spread application of this therapy. Biological agents that block key T-cell costimulatory signals, in particular the CD28 pathway, have demonstrated extraordinary promise in animal models. LEA29Y (BMS-224818), a mutant CTLA4-Ig molecule with increased binding activity, was evaluated for its potential to replace tacrolimus and protect allogeneic islets in a preclinical primate model. Animals received either the base immunosuppression regimen (rapamycin and anti-IL-2R monoclonal antibody [mAb]) or the base immunosuppression and LEA29Y. Animals receiving the LEA29Y/rapamycin/anti-IL-2R regimen (n = 5) had significantly prolonged islet allograft survival (204, 190, 216, 56, and >220 days). In contrast, those animals receiving the base regimen alone (n = 2) quickly rejected the transplanted islets at 1 week (both at 7 days). The LEA29Y-based regimen prevented the priming of anti-donor T- and B-cell responses, as detected by interferon-gamma enzyme-linked immunospot and allo-antibody production, respectively. The results of this study suggest that LEA29Y is a potent immunosuppressant that can effectively prevent rejection in a steroid-free immunosuppressive protocol and produce marked prolongation of islet allograft survival in a preclinical model.

Developmental reorganization of the output of a GABAergic interneuronal circuit.

Locally projecting inhibitory interneurons play a crucial role in the patterning and timing of network activity. However, because of their relative inaccessibility, little is known about their development or incorporation into circuits. In this report we demonstrate that the GABAergic R-interneuron circuit undergoes a reorganization in the chick embryo spinal cord between embryonic days 8 and 15 (E8 and E15). R-interneurons receive synaptic input from and project back to motoneurons. By stimulating motoneurons projecting in one ventral root and recording the disynaptic response from motoneurons in adjacent segments, we show that the output of the R-interneuron circuit is reorganized during development. After stimulation of the LS2 ventral root, disynaptic responses observed in whole cell recordings became more common and stronger for LS3 motoneurons and less common for the more distant LS4 motoneurons from E8 to E10. Optical studies demonstrated that R-interneurons activated by LS2 stimulation were restricted to the LS2 segment and had a small glutamatergic component at both E8 and E10, but that more R-interneurons were activated within the segment by E10. The recruitment of more LS2 R-interneurons at E10 is likely to contribute to stronger projections to LS3 motoneurons, but the fact that fewer LS4 motoneurons receive this input is more consistent with a functional refinement of the more distant projection of the GABAergic R-interneuron. Interestingly, this pattern of reorganization was not observed throughout the rostrocaudal extent of the cord, introducing the possibility that refinement could serve to remove connections between functionally unrelated interneurons and motoneurons.

Development of an inhibitory interneuronal circuit in the embryonic spinal cord.

Locally projecting inhibitory interneurons play a crucial role in the patterning and timing of network activity. However, because of their relative inaccessibility, little is known about their development or incorporation into circuits. In this study, we characterized the functional onset, neurotransmitters, rostrocaudal spread, and funicular distribution of one such spinal interneuronal circuit during development. The R-interneuron is the avian homologue of the mammalian Renshaw cell. Both cell types receive input from motoneuron recurrent collaterals and make direct connections back onto motoneurons. By stimulating motoneurons projecting in a given ventral root and recording the response in adjacent ventral roots, we demonstrate that the R-interneuron circuit becomes functional between embryonic day 6 (E6) and E7. This ventral root response is observed at E11 and at E14 until it can no longer be detected at E16. Using bath-applied neurotransmitter receptor antagonists, we were able to demonstrate that the circuit is predominately nicotinic and GABAergic from E7.5 to E15. We also found a glutamatergic component to the pathway throughout this developmental period. The R-interneuron projects three or more segments both rostrally and caudally through the ventrolateral funiculus. The distribution of this circuit may become more locally focused between E7.5 and E15.

Differences in transient outward current properties between neonatal and adult human atrial myocytes.

UNLABELLED: Knowledge of postnatal modulation of I(to) in human atrial myocytes is quite limited. The present study investigated the differences in I(to) properties between neonatal and adult human atrial myocytes. METHODS: Atrial myocytes were dissociated enzymatically from biopsies of human right atrial appendage. I(to) and action potentials were recorded by whole-cell patch-clamp technique. The expressed protein levels of Kv4.3 and KChIP2 in atrial tissue were detected by western blot technique. RESULTS: I(to) was present in all atrial cells (n = 37) from 10 neonatal patients (2.5-7 months). The mean value of I(to) density in neonatal atrial cells was significantly larger than in adult atrial cells. The time constants for I(to) current decay were significantly faster for neonatal cells, compared to adult cells. I(to) recovery from inactivation at holding potential of - 80 mV was significantly slower for neonatal atrial cells than for adult atrial cells. There was no difference in the voltage dependence of I(to) activation between neonatal and adult cells. The voltage-dependent inactivation slope factor was smaller for neonatal compared to adult atrial cells. A more significant frequency-dependent suppression of I(to) peak current and a more significant lengthening of APD(30) were observed in neonatal atrial cells compared to adult atrial cells. Western blots showed both Kv4.3 and KChIP2 are expressed in neonatal atria, but with significantly higher level of Kv4.3 and lower level of KChIP2 protein compared to adult. CONCLUSION: There are significant differences in the properties of I(to) between neonatal and adult human atrial cells, including a larger current density, faster inactivation and slower recovery from inactivation in the neonatal atrial cells. The physiological differences of I(to) are consistent with the different expression protein levels of Kv4.3 and KChIP2.

Prevention of chronic rejection in murine cardiac allografts: a comparison of chimerism- and nonchimerism-inducing costimulation blockade-based tolerance induction regimens.

We have previously described a nonirradiation-based regimen combining costimulation blockade, busulfan, and donor bone marrow cells that promotes stable, high level chimerism, deletion of donor-reactive T cells, and indefinite survival of skin allografts in mice. The purpose of the current study is to determine the efficacy of this tolerance regimen in preventing acute and chronic rejection in a vascularized heart graft model and to compare this regimen with other putative tolerance protocols. Mice receiving costimulation blockade (CTLA4-Ig and anti-CD40 ligand) alone or in combination with donor cells enjoyed markedly prolonged heart graft survival and initially preserved histological structure. However, tolerance was not achieved, as evidenced by the eventual onset of chronic rejection characterized by obliterative vasculopathy and the rejection of secondary skin grafts. In contrast, following treatment with costimulation blockade, busulfan, and bone marrow, heart grafts survived indefinitely without detectable signs of chronic rejection or structural damage, even 100 days after placement of a secondary donor skin graft. We detected multilineage chimerism in peripheral blood, spleen, lymph nodes, and thymus, and peripheral deletion of donor-reactive cells was complete by day 90. These findings indicate that only the CD40/CD28 blockade chimerism induction regimen prevents both acute and chronic rejection of vascularized organ transplants. Further testing of these strategies in a preclinical large animal model is warranted.