Case report: Blotchy skin in a puffy neonate: is there a new association?

Introduction: Purpura fulminans in the neonatal population is a rare but potentially life-threatening condition complicated by thrombosis, resultant vital organ necrosis, and gangrene of the extremities. Considering the rapid evolution of the pathogenetic mechanism, an index of suspicion, early identification, and prompt intervention are imperative for improved outcomes. The majority of purpura fulminans cases have an infectious etiology, but it is essential to consider other congenital and acquired causes. Case description: We present a clinical case of a female neonate to emphasize the correlation between purpura fulminans, congenital chylothorax, involvement of the PAK2 gene, and the occurrence of retinal detachment in both eyes. After draining the congenital chylothorax, the neonate developed purpura fulminans due to a loss of protein C, S, and antithrombin factors, previously not reported in the literature. The purpuric lesions resolved after the administration of fresh frozen plasma. Subsequently, no recurring purpura fulminans lesions were noted following the normalization of the antithrombotic factor levels in the serum. Subsequently, the child also developed retinal detachment in both eyes.

Structured Referral Call Handling Process Improves Neonatal Transport Dispatch Times.

OBJECTIVE: In 2019 the Southern Alberta Neonatal Transport Service adopted a transport call handling process change to expedite transport team mobilization. This study compares the impact of this change on neonatal transport decision to dispatch and mobilization times. STUDY DESIGN: This retrospective cohort study was conducted using a historical cohort of neonates referred for transportation between January 2017 and December 2021. The "dispatch time" (DT) was the time from the start of consultation to the time a decision to dispatch the transport team was made, whereas "mobilization time" (MT) referred to the time from start of consultation to the time the team departed the home base. In 2019, a DT target of <3 minutes was implemented to meet a target MT of <15 and <30 minutes for emergent and urgent high-risk transport referral calls, respectively. In 2021 use of the "Situation" component of the SBAR (Situation, Background, Assessment, Recommendation) communication tool was introduced with the transport team asking five questions to determine need for mobilization. Data between 2017 and 2018 represented the preintervention period, 2019, the "washout" period for implementation, and 2020 to 2021, the postintervention period. Data were analyzed to determine trends in DT and MT. RESULTS: The DT was reduced from a median of 5 to 3 minutes following intervention (p < 0.001). DT target goal of 3 minutes was achieved in 67.08% of calls compared with 26.24% in the preintervention period, (p < 0.001). The team achieved MT target goals in 42.71% of urgent and emergent transfers compared with 18.05% prior to intervention (p < 0.001). CONCLUSION: Introduction of a time-sensitive referral call handling process improved dispatch and mobilization time of the neonatal transport team. KEY POINTS: · Time-sensitive triaging of neonatal transport referrals improves dispatch and mobilization time.. · A structured referral call handling process improves the efficiency of neonatal transport decision-making.. · Dedicated neonatal transport vehicles are likely to improve neonatal transport mobilization time..

Neurodevelopmental Outcomes of Preterm Infants Born <29 Weeks with Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension: A Multicenter Study.

OBJECTIVE: This study aimed to determine neurodevelopmental outcomes of preterm infants born at <29 weeks' gestational age (GA) with bronchopulmonary dysplasia and pulmonary hypertension (BPD-PH) at 18 to 24 months' corrected age (CA). STUDY DESIGN: In this retrospective cohort study, preterm infants born at <29 weeks' GA between January 2016 and December 2019, admitted to level 3 neonatal intensive care units, who developed BPD and were evaluated at 18 to 24 months' CA in the neonatal follow-up clinics were included. We compared demographic characteristics and neurodevelopmental outcomes between the two groups: Group I: BPD with PH and Group II: BPD with no PH, using univariate and multivariate regression models. The primary outcome was a composite of death or neurodevelopmental impairment (NDI). NDI was defined as any Bayley-III score < 85 on one or more of the cognitive, motor, or language composite scores. RESULTS: Of 366 eligible infants, 116 (Group I [BPD-PH] =7, Group II [BPD with no PH] = 109) were lost to follow-up. Of the remaining 250 infants, 51 in Group I and 199 in Group II were followed at 18 to 24 months' CA. Group I and Group II had median (interquartile range [IQR]) birthweights of 705 (325) and 815 g (317; p = 0.003) and median GAs (IQR) were 25 (2) and 26 weeks (2; p = 0.015) respectively. Infants in the BPD-PH group (Group I) were more likely to have mortality or NDI (adjusted odds ratio: 3.82; bootstrap 95% confidence interval; 1.44-40.87). CONCLUSION: BPD-PH in infants born at <29 weeks' GA is associated with increased odds of the composite outcome of death or NDI at 18 to 24 months' CA. KEY POINTS: · Long-term neurodevelopmental follow-up of preterm infants born <29 weeks' GA.. · Association of neurodevelopmental outcomes with BPD-associated PH.. · Need for longitudinal follow-up of children with BPD-associated PH..

Retinoic Acid Receptor γ Regulates B and T Lymphopoiesis via Nestin-Expressing Cells in the Bone Marrow and Thymic Microenvironments.

Vitamin A has essential but largely unexplained roles in regulating lymphopoiesis. We have previously shown that retinoic acid receptor (RAR) γ-deficient mice have hematopoietic defects, some phenotypes of which were microenvironment induced. Bone marrow (BM) microenvironment cells identified by either their expression of nestin (Nes) or osterix (Osx) have previously been shown to have roles in regulating lymphopoiesis. We therefore conditionally deleted Rarγ in Nes- or Osx-expressing microenvironment cells. Osx cell-specific deletion of Rarγ had no impact on hematopoiesis. In contrast, deletion of Rarγ in Nes-expressing cells resulted in reductions in peripheral blood B cells and CD4(+) T cells, accompanied by reductions of immature PreB cells in BM. The mice lacking Rarγ in Nes-expressing cells also had smaller thymi, with reductions in double-negative 4 T cell precursors, accompanied by reduced numbers of both TCRß(low) immature single-positive CD8(+) cells and double-positive T cells. In the thymus, Nes expression was restricted to thymic stromal cells that expressed cerebellar degeneration-related Ag 1 and lacked expression of epithelial cell adhesion molecule. These cells expressed platelet-derived growth factor α and high transcript levels of Rars, Cxcl12, and stem cell factor (Scf). Short-term treatment of mice with all-trans retinoic acid resulted in increased PreB lymphopoiesis in BM and an increase in thymic double-negative 4 T cells, inverse to that observed upon Nes cell-specific deletion of Rarγ. Collectively, these studies show that RARγ is a regulator of B and T lymphopoiesis via Nes-expressing cells in the BM and thymic microenvironments, respectively.

Acute liver failure in dengue haemorrhagic fever.

While dengue virus infection leads to a mild to moderate elevation of liver transaminases in almost all cases, hepatic failure rarely dominates the clinical picture in adults. We present a case of dengue haemorrhagic fever in a young adult, leading to the rare complication of acute liver failure. He was managed with supportive care and discharged after 5 days. At follow-up after 1 week, he had complete recovery and no residual symptoms.

Erythroid-extrinsic regulation of normal erythropoiesis by retinoic acid receptors.

Vitamin A and its derivatives (retinoids) are important regulators of haematopoiesis, acting via retinoic acid receptors (RARs). Epidemiological studies indicated an association of vitamin A deficiency with anaemia in humans. To define the requirements of RARs in erythropoiesis, we evaluated erythroid parameters in RAR germ-line deficient and conditional knock out mice with erythroid specific deletion of RARs. Adult RARγ(-/-) mice were anaemic, however, Epor-Cre Rara(fl/fl) , Epor-Cre Rarg(fl/fl) and Epor-Cre Rara(fl/fl) g(fl/fl) mice were normal, indicating a lack of an erythroid intrinsic RAR function. Therefore, erythroid-specific RAR function is dispensable for erythropoiesis and RARγ plays an erythroid extrinsic role in erythropoiesis.

Deciphering hematopoietic stem cells in their niches: a critical appraisal of genetic models, lineage tracing, and imaging strategies.

In recent years, technical developments in mouse genetics and imaging equipment have substantially advanced our understanding of hematopoietic stem cells (HSCs) and their niche. The availability of numerous Cre strains for targeting HSCs and microenvironmental cells provides extensive flexibility in experimental design, but it can also pose significant challenges due to strain-specific differences in cell specificity. Here we outline various genetic approaches for isolating, detecting, and ablating HSCs and niche components and provide a guide for advantages and caveats to consider. We also discuss opportunities and limitations presented by imaging technologies that allow investigation of HSC behavior in situ.

Glypican-3-mediated inhibition of CD26 by TFPI: a novel mechanism in hematopoietic stem cell homing and maintenance.

Directional migration determines hematopoietic stem/progenitor cell (HSPC) homing, which depends upon the interaction between the chemokine CXCL12 and its receptor CXCR4. CD26 is a widely expressed membrane-bound ectopeptidase that cleaves CXCL12 thereby depleting its chemokine activity. We identified tissue-factor pathway inhibitor (TFPI) as a biological inhibitor of CD26 in murine and human HSPCs. We observed low-level TFPI expression in endothelial cells in the bone marrow (BM), which did not increase following radiation injury. Treatment of HSPCs with TFPI in vitro led to enhanced HSPC migration toward CXCL12, as well as homing and engraftment in the BM upon transplantation. We found that Glypican-3 (GPC3), a heparan sulfate proteoglycan expressed on murine as well as human HSPCs, mediated this effect. TFPI did not affect CD26 activity, migration, or homing of GPC3(-/-) HSPCs, while it affected GPC1(-/-) HSPCs similar to wild-type HSPCs. Moreover, proliferation of GPC3(-/-) but not GPC1(-/-) BM HSPCs was significantly increased, which was associated with a decrease in the primitive HSC pool in BM and an increase in proportion of the circulating HSPCs in the peripheral blood. Hence, we present a novel role for TFPI and GPC3 in regulating HSC homing as well as retention in the BM.

Increased potency of cardiac stem cells compared with bone marrow mesenchymal stem cells in cardiac repair.

Whereas cardiac-derived c-kit(+) stem cells (CSCs) and bone marrow-derived mesenchymal stem cells (MSCs) are undergoing clinical trials testing safety and efficacy as a cell-based therapy, the relative therapeutic and biologic efficacy of these two cell types is unknown. We hypothesized that human CSCs have greater ability than MSCs to engraft, differentiate, and improve cardiac function. We compared intramyocardial injection of human fetal CSCs (36,000) with two doses of adult MSCs (36,000 and 1,000,000) or control (phosphate buffered saline) in nonobese diabetic/severe combined immune deficiency mice after coronary artery ligation. The myocardial infarction-induced enlargement in left ventricular chamber dimensions was ameliorated by CSCs (p < .05 for diastolic and systolic volumes), as was the decline in ejection fraction (EF; p < .05). Whereas 1 × 10(6) MSCs partially ameliorated ventricular remodeling and improved EF to a similar degree as CSCs, 36,000 MSCs did not influence chamber architecture or function. All cell therapies improved myocardial contractility, but CSCs preferentially reduced scar size and reduced vascular afterload. Engraftment and trilineage differentiation was substantially greater with CSCs than with MSCs. Adult-cultured c-kit(+)CSCs were less effective than fetal, but were still more potent than high-dose MSCs. These data demonstrate enhanced CSC engraftment, differentiation, and improved cardiac remodeling and function in ischemic heart failure. MSCs required a 30-fold greater dose than CSCs to improve cardiac function and anatomy. Together, these findings demonstrate a greater potency of CSCs than bone marrow MSCs in cardiac repair.

Slow breathing improves arterial baroreflex sensitivity and decreases blood pressure in essential hypertension.

Sympathetic hyperactivity and parasympathetic withdrawal may cause and sustain hypertension. This autonomic imbalance is in turn related to a reduced or reset arterial baroreflex sensitivity and chemoreflex-induced hyperventilation. Slow breathing at 6 breaths/min increases baroreflex sensitivity and reduces sympathetic activity and chemoreflex activation, suggesting a potentially beneficial effect in hypertension. We tested whether slow breathing was capable of modifying blood pressure in hypertensive and control subjects and improving baroreflex sensitivity. Continuous noninvasive blood pressure, RR interval, respiration, and end-tidal CO2 (CO2-et) were monitored in 20 subjects with essential hypertension (56.4+/-1.9 years) and in 26 controls (52.3+/-1.4 years) in sitting position during spontaneous breathing and controlled breathing at slower (6/min) and faster (15/min) breathing rate. Baroreflex sensitivity was measured by autoregressive spectral analysis and "alpha angle" method. Slow breathing decreased systolic and diastolic pressures in hypertensive subjects (from 149.7+/-3.7 to 141.1+/-4 mm Hg, P<0.05; and from 82.7+/-3 to 77.8+/-3.7 mm Hg, P<0.01, respectively). Controlled breathing (15/min) decreased systolic (to 142.8+/-3.9 mm Hg; P<0.05) but not diastolic blood pressure and decreased RR interval (P<0.05) without altering the baroreflex. Similar findings were seen in controls for RR interval. Slow breathing increased baroreflex sensitivity in hypertensives (from 5.8+/-0.7 to 10.3+/-2.0 ms/mm Hg; P<0.01) and controls (from 10.9+/-1.0 to 16.0+/-1.5 ms/mm Hg; P<0.001) without inducing hyperventilation. During spontaneous breathing, hypertensive subjects showed lower CO2 and faster breathing rate, suggesting hyperventilation and reduced baroreflex sensitivity (P<0.001 versus controls). Slow breathing reduces blood pressure and enhances baroreflex sensitivity in hypertensive patients. These effects appear potentially beneficial in the management of hypertension.