Comparison of viral load and duration of virus shedding in symptomatic and asymptomatic neonatal rotavirus infections

A single rotavirus strain causing asymptomatic infections as well as severe gastrointestinal disease has been described in the neonatal nurseries of the Christian Medical College, Vellore. In this study, quantitative real‐time RT‐PCR was used to determine the association of viral load with the presence of gastrointestinal symptoms in neonates. Viral load was estimated in terms of the crossing point [C(t) value] at which the amplicon could be detected in the real‐time PCR assay. The study was carried out on 103 neonates, including 33 asymptomatic neonates and 70 neonates with different gastrointestinal symptoms. The duration of virus shedding was also compared between five symptomatic and four asymptomatic neonates using real‐time RT‐PCR. There was no significant difference in viral load between symptomatic and asymptomatic neonates (P = 0.087). Among neonates with different gastrointestinal symptoms, those presenting with feed intolerance and abdominal distension had a significantly higher viral load than those with other gastrointestinal symptoms (P = 0.02). For the study on virus shedding, nine neonates were followed up for a median duration of 53 days, with a median of 31 samples tested per child. Extended shedding of low copies of rotavirus was found, with no significant differences in pattern of shedding between symptomatic and asymptomatic neonates. The lack of correlation between viral load and gastrointestinal disease demonstrates yet another difference between neonatal rotavirus infection and infection in older children where higher viral load correlates with severe disease. J. Med. Virol. 82:1803–1807, 2010. © 2010 Wiley‐Liss, Inc.     

Systemic sclerosis in childhood: clinical and immunologic features of 153 patients in an international database

OBJECTIVE: To determine the clinical and immunologic features of systemic sclerosis (SSc) in a large group of children and describe the clinical evolution of the disease and compare it with the adult form. METHODS: Data on 153 patients with juvenile SSc collected from 55 pediatric rheumatology centers in Europe, Asia, and South and North America were analyzed. Demographic, clinical, and immunologic characteristics of children with juvenile SSc at the onset, at diagnosis, and during the disease course were evaluated. RESULTS: Raynaud's phenomenon was the most frequent symptom, followed by skin induration in approximately 75% of patients. Musculoskeletal symptoms were present in one-third of patients, and the most frequently involved internal organs were respiratory and gastrointestinal, while involvement of renal, cerebral, and cardiovascular systems was extremely rare. Antinuclear antibodies were present in the sera of 81% of patients. Anti-topoisomerase I (Scl-70) and anticentromere antibodies were found to be positive in 34% and 7.1% of patients, respectively. Involvement of the respiratory, gastrointestinal, and cardiovascular systems was more frequent and occurred earlier in patients who died than in those who survived. Compared with the adult form, juvenile SSc appears to be less severe, with the involvement of fewer internal organs, particularly at the time of diagnosis, and has a less characterized immunologic profile. CONCLUSION: This study provides information on the largest collection of patients with juvenile SSc ever reported. Juvenile SSc appears to be less severe than in adults because children have less internal organ involvement, a less specific autoantibody profile, and a better long-term outcome.     

PLA(2) signaling is involved in calpain-mediated degradation of synaptic dihydropyrimidinase-like 3 protein in response to NMDA excitotoxicity

Dihydropyrimidinase-like 3 (DPYSL3) is believed to play a role in neuronal differentiation, axonal outgrowth and neuronal regeneration, as well as cytoskeleton organization. Recently we have shown that glutamate excitotoxicity and oxidative stress result in calpain-dependent cleavage of DPYSL3, and that NOS plays a role in this process [R. Kowara, Q. Chen, M. Milliken, B. Chakravarthy, Calpain-mediated truncation of dihydropyrimidinase-like 3 protein (DPYSL3) in response to NMDA and H2O2 toxicity, J. Neurochem. 95 (2005) 466–474; R. Kowara, K.L. Moraleja, B. Chakravarthy, Involvement of nitric oxide synthase and ROS-mediated activation of L-type voltage-gated Ca(2+) channels in NMDA-induced DPYSL3 degradation, Brain Res. 1119 (2006) 40–49]. The present study investigates the involvement of PLA₂ signaling in NMDA-induced DPYSL3 degradation. Exposure of rat primary cortical neurons (PCN) to PLA₂ and COX-2 inhibitors significantly prevented NMDA-induced DPYSL3 degradation. Since the metabolic product of PLA₂ signaling, PGE₂, which augments toxic effect of NMDA, is known to stimulate cAMP, the effect of adenyl cyclase activator (forskolin plus IBMX) and inhibitor (MDL12,300) on NMDA-induced DPYSL3 degradation was tested. Our data indicate that the activation of adenyl cyclase contributes to NMDA-induced DPYSL3 degradation. Furthermore, cAMP-dependent protein kinase (PKA) inhibitor PKI (14–22) provided additional evidence of PKA involvement in NMDA-induced DPYSL3 degradation. In summary, the obtained data show the contribution of PLA₂ signaling to NMDA-induced calpain activation and subsequent degradation of synaptic protein DPYSL3.     

Rb intrinsically promotes erythropoiesis by coupling cell cycle exit with mitochondrial biogenesis

Regulation of the cell cycle is intimately linked to erythroid differentiation, yet how these processes are coupled is not well understood. To gain insight into this coordinate regulation, we examined the role that the retinoblastoma protein (Rb), a central regulator of the cell cycle, plays in erythropoiesis. We found that Rb serves a cell-intrinsic role and its absence causes ineffective erythropoiesis, with a differentiation block at the transition from early to late erythroblasts. Unexpectedly, in addition to a failure to properly exit the cell cycle, mitochondrial biogenesis fails to be up-regulated concomitantly, contributing to this differentiation block. The link between erythropoiesis and mitochondrial function was validated by inhibition of mitochondrial biogenesis. Erythropoiesis in the absence of Rb resembles the human myelodysplastic syndromes, where defects in cell cycle regulation and mitochondrial function frequently occur. Our work demonstrates how these seemingly disparate pathways play a role in coordinately regulating cellular differentiation.     

Vasoactive agents modulate migration of monocytes across glomerular endothelial cells.

BACKGROUND: Macrophages seem to play an important role in the development of glomerulosclerosis. In both human and experimental animal models of focal glomerulosclerosis (FSGS), infiltration of macrophages in the mesangium has been considered key in the development of FSGS. METHODS: In the present study, we evaluated the effect of vasoactive agents on the migration of monocytes across a filter in a modified Boyden chamber as well as across a cultured glomerular endothelial cell layer (in vitro model of glomerular mesangium). Both light as well as scanning electron microscopic studies were performed. We evaluated the effect of vasoactive agents including histamine, prostaglandin (PG) E2, angiotensin II, endothelin-1, platelet-activating factor, and interleukin-1 (IL) on the migration of monocytes/macrophages across an endothelial cell layer as well as a gelatin-coated filter. In addition, we evaluated the effect of cyclic adenosine 3',5' cyclic monophosphate (cAMP) and PGE2 on vasoactive-induced migration of monocytes. RESULTS: Histamine increased (P < 0.003) the migration of monocytes across the filter. This effect of histamine was dose-dependent. Histamine at concentrations of 10(-8) to 10(-5) mol/L induced optimal migration across the filter (control, 16.6 +/- 1.1 vs histamine, 10(-8) mol/L, 40.9 +/- 0.9 monocytes/high power field). Cimetidine, an H2 receptor blocker, attenuated (P < 0.001) the effect of histamine on the migration of monocytes. PGE2 inhibited the migration of monocytes in a dose-dependent manner. Histamine increased (P < 0.001) the passage of monocytes across the glomerular endothelial cell layer (control, 1012 +/- 37 vs 1711 +/- 163 cpm/well). Histamine also increased the migration of murine macrophages across the glomerular endothelial cell layer. PGE2 inhibited the migration of monocytes across the endothelial cell layer under basal as well as histamine-stimulated states. Dibutyryl cyclic (DBc) AMP also attenuated the migration of monocytes under basal as well as histamine-stimulated states. Both PGE2 and DBcAMP also attenuated the IL-1 beta-stimulated migration of monocytes. Angiotensin II, endothelin-1, and platelet-activating factor did not modulate the migration of monocytes. CONCLUSIONS: Vasoactive agents directly modulate the transmigration of monocytes. The present in vitro study provides a basis for a hypothesis that vasoactive agents may also be modulating the migration of monocytes across the glomerular endothelial cell layer (into the mesangium).