Initial Characteristics and Clinical Severity of Hemophagocytic Lymphohistiocytosis in Pediatric Patients Admitted in the Emergency Department.

OBJECTIVES: The diagnosis and management of children with hemophagocytic lymphohistiocytosis (HLH) admitted in the emergency department (ED) are challenging. The present study aimed at describing the initial characteristics of pediatric patients with HLH upon admission in the ED. Moreover, the clinical severity of the condition was assessed. METHODS: We performed a retrospective study of patients who visited the pediatric ED and were newly diagnosed with HLH during hospitalization between February 2012 and January 2017. The patients were classified in the clinically unstable group if at least 1 of the following conditions was observed upon admission in the ED: hypoxia requiring oxygen supplementation, hypotension requiring inotropic support, coagulopathy with prothrombin time (international normalized ratio, ≥1.5), and seizures or altered consciousness. RESULTS: We enrolled 31 pediatric patients with HLH, with a median age of 6.53 years (interquartile range, 1.35-13.24 years). Abdominal discomfort along with fever (74.2%) was the most common presenting symptom in patients admitted in the ED. Based on the HLH-2004 diagnostic criteria, fever (96.8%), hyperferritinemia (96.8%), splenomegaly (74.2%), hypertriglyceridemia and/or hypofibrinogenemia (67.7%), and bicytopenia (41.9%) were observed in the patients. However, only 8 patients (25.8%) met the criteria. Nineteen patients (61.3%) were included in the clinically unstable group. This group had lower albumin (2.3 vs 3.3 g/dL, P = 0.002) and fibrinogen levels and higher ferritin level and neutrophil count than the clinically stable group. Meanwhile, the number of clinical findings that met the diagnostic criteria was not different between the 2 groups. Lower albumin level was a significant risk factor in the clinically unstable group (odds ratio, 0.040; P = 0.004). CONCLUSIONS: Pediatric patients with HLH often have clinically unstable conditions upon admission in the ED. However, only few patients meet the HLH-2004 diagnostic criteria. Lower albumin level may be useful in assessing clinically unstable patients and preparing for possible deterioration.

Human Cytomegalovirus-Induced Interleukin-10 Production Promotes the Proliferation of Mycobacterium massiliense in Macrophages.

Human cytomegalovirus (HCMV) exploits the interleukin-10 (IL-10) pathway as a part of its infection cycle through the manipulation of the host IL-10 signaling cascade. Based on its immunomodulatory nature, HCMV attenuates the host immune response and facilitates the progression of co-infection with other pathogens in an immune-competent host. To investigate the impact of HCMV infection on the burden of non-tuberculous mycobacteria (NTM), whose prevalence is growing rapidly worldwide, macrophages were infected with HCMV and further challenged with Mycobacterium massiliense in vitro. The results showed that HCMV infection significantly increased host IL-10 synthesis and promoted the proliferation of M. massiliense in an IL-10-dependent manner. Transcriptomic analysis revealed that HCMV infection dampened the regulatory pathways of interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), and interleukin-1 (IL-1), consequently abrogating the immune responses to M. massiliense coinfection in macrophages. These findings provide a mechanistic basis of how HCMV infection may facilitate the development of pathogenic NTM co-infection by upregulating IL-10 expression.

HCMV-induced signaling through gB-EGFR engagement is required for viral trafficking and nuclear translocation in primary human monocytes.

Previous analysis of postentry events revealed that human cytomegalovirus (HCMV) displays a unique, extended nuclear translocation pattern in monocytes. We determined that c-Src signaling through pentamer engagement of integrins is required upon HCMV entry to avoid sorting of the virus into late endosomes and subsequent degradation. To follow up on this previous study, we designed experiments to investigate how HCMV-induced signaling through the other major axis-the epidermal growth factor receptor (EGFR) kinase-regulates viral postentry events. Here we show that HCMV induces chronic and functional EGFR signaling that is distinct to the virus as compared to the natural EGFR ligand: EGF. This chronic EGFR kinase activity in infected monocytes is required for the proper subcellular localization of the viral particle during trafficking events, as well as for promoting translocation of viral DNA into the host nucleus. Our data indicate that HCMV glycoprotein B (gB) binds to EGFR at the monocyte surface, the virus and EGFR are internalized together, and gB remains bound to EGFR throughout viral postentry events until de-envelopment to promote the chronic EGFR kinase activity required for viral trafficking and nuclear translocation. These data highlight how initial EGFR signaling via viral binding is necessary for entry, but not sufficient to promote each viral trafficking event. HCMV appears to manipulate the EGFR kinase postentry, via gB-EGFR interaction, to be active at the critical points throughout the trafficking process that leads to nuclear translocation and productive infection of peripheral blood monocytes.

Point-of-Care Ultrasound Could Streamline the Emergency Department Workflow of Clinically Nonspecific Intussusception.

OBJECTIVES: The aim of this study was to evaluate whether point-of-care ultrasound (POCUS) for intussusception screening streamlines the workflow of clinically nonspecific intussusception (CNI), an intussusception presenting with only 1 manifestation of the classic triad, and/or vomiting. METHODS: We reviewed 274 consecutive children with intussusception, aged 6 years or younger, who visited a tertiary care hospital emergency department between May 2012 and April 2016. This period was dichotomized by May 2014 (the "PRE" and "POST" groups), starting point of implementation of the POCUS protocol for intussusception screening. All children with CNI who had positive results on or forwent POCUS underwent radiologist-performed ultrasound (US). We measured and compared emergency department length of stay (EDLOS), the sum of door-to-reduction and observation times, and the frequency of POCUS and positive US results between the 2 groups. RESULTS: Of 160 children with CNI, 93 visited the emergency department since May 2014. The POST group showed a shorter median EDLOS (856 vs 630 minutes, P < 0.001), door-to-reduction time (137 vs 111 minutes, P = 0.002), and observation time (700 vs 532 minutes, P < 0.001). The POST group had a higher frequency of POCUS (12% vs 60%, P < 0.001) with positive US results (33% vs 59%, P < 0.001). The PRE group had a higher frequency of severe bowel edema (16% vs 1%, P < 0.001). No significant differences were found in the severity, recurrence, admission, and surgery. One child had a false-negative result on POCUS. CONCLUSIONS: Point-of-care ultrasound could streamline the workflow of CNI via decrease in EDLOS and unnecessary referrals for US.

Delayed adenosine therapy is associated with the refractory supraventricular tachycardia in children.

OBJECTIVES: To study the association of time intervals on adenosine therapy with the occurrence of refractory supraventricular tachycardia (SVT) in children. METHODS: We reviewed 334 episodes of presumed SVT requiring adenosine in children (<18 years) who visited 4 academic hospital emergency departments (EDs) from July 2013 through June 2017. Refractory SVT was defined as an SVT episode persisting after 2 doses of adenosine. Clinical and electrocardiographic findings, and symptom-to-adenosine (symptom-to-ED plus ED-to-adenosine) time of refractory and responsive SVT episodes were compared. Multivariable logistic regression was performed to identify factors associated with the occurrence of refractory SVT. RESULTS: Of 211 SVT episodes, 42 episodes of refractory SVT (19.9%) were noted (overall sinus conversion rate, 79.6%). The refractory episodes were associated with a higher frequency of known structural heart diseases (9.5% vs. 1.8%; P = 0.030) and a longer median ED-to-adenosine time (15.5 vs. 11.0 min; P = 0.018). The association of the ED-to-adenosine time with refractory SVT remained significant after adjustment (for increment of 1 min; aOR, 1.02; 95% CI, 1.007-1.04). CONCLUSIONS: Delayed adenosine therapy is associated with the occurrence of refractory SVT in children, supporting the need for prompt adenosine therapy.

Risk Stratification of Intermediate-Risk Children With Minor Head Injury.

The Pediatric Emergency Care Applied Research Network rule helps emergency physicians identify very low-risk children with minor head injury who can forgo head computed tomography. This rule contributes to reduction in lifetime risk of radiation-induced cancers while minimizing missing clinically important traumatic brain injury. However, in intermediate-risk children, decisions on whether to perform computed tomography remain at the emergency physicians' discretion. To reduce this gray zone, this review summarizes evidence for risk stratification of intermediate-risk children with minor head injury.

Requirement for Head Magnetic Resonance Imaging in Children Who Present to the Emergency Department With Acute Nontraumatic Visual Disturbance.

OBJECTIVES: This study aimed to investigate the clinical features and head magnetic resonance imaging (MRI) findings in children who presented to the emergency department with acute nontraumatic visual disturbance and to study related clinical factors for discovering positive lesions on head MRI. METHODS: We performed a retrospective study of 1-month to 15-year-old children who underwent head MRI as an evaluation for acute nontraumatic visual disturbance as a chief complaint in our pediatric emergency department between March 2010 and March 2015. The symptoms of visual disturbance were blurred vision, diplopia, loss of vision, and visual hallucination. Head MRI findings were considered positive when lesions could explain the symptoms. RESULTS: We identified 39 patients (25 with blurred vision, 9 with diplopia, 3 with loss of vision, and 2 with visual hallucination) with a mean age of 8.35 ± 4.06 years. Positive head MRI findings were identified in 13 patients (33.3%). Brain tumors were most common (53.8%), followed by optic nerve inflammations (23.1%), congenital brain lesions (15.4%), and hypertensive encephalopathy (7.7%). Compared with the negative head MRI group, the positive head MRI group showed significantly less transient visual disturbance (duration <1 hour to complete recovery) (P = 0.001), more limited eye movement (P = 0.003), and more pupillary abnormalities (P = 0.030). CONCLUSIONS: We suggest performing urgent head MRI in children with acute nontraumatic visual disturbance if the symptoms last longer than 1 hour without complete recovery and are accompanied by limited eye movement or pupillary abnormality.

Human Cytomegalovirus Encodes a Novel FLT3 Receptor Ligand Necessary for Hematopoietic Cell Differentiation and Viral Reactivation.

The ability of human cytomegalovirus (HCMV) to reactivate from latent infection of hematopoietic progenitor cells (HPCs) is intimately linked to cellular differentiation. HCMV encodes UL7 that our group has shown is secreted from infected cells and induces angiogenesis. In this study, we show that UL7 is a ligand for Fms-like tyrosine kinase 3 receptor (Flt-3R), a well-known critical factor in HPC differentiation. We observed that UL7 directly binds Flt-3R and induces downstream signaling cascades, including phosphatidylinositol 3-kinase (PI3K)/Akt and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathways. Importantly, we show that UL7 protein induces differentiation of both CD34+ HPCs and CD14+ monocytes. Last, we show that an HCMV mutant lacking UL7 fails to reactivate in CD34+ HPCs in vitro as well as in humanized mice. These observations define the first virally encoded differentiation factor with significant implications not only for HCMV reactivation but also for alteration of the hematopoietic compartment in transplant patients.IMPORTANCE Human cytomegalovirus (HCMV) remains a significant cause of morbidity and mortality in allogeneic hematopoietic stem cell transplant recipients. CD34+ hematopoietic progenitor cells (HPCs) represent a critical reservoir of latent HCMV in the transplant population, thereby providing a source of virus for dissemination to visceral organs. HCMV reactivation has been linked to HPC/myeloid cellular differentiation; however, the mechanisms involved in these events are poorly understood at the molecular level. In this study, we show that a viral protein is a ligand for Fms-like tyrosine kinase 3 receptor (Flt-3R) and that the binding of HCMV UL7 to the Flt-3R triggers HPC and monocyte differentiation. Moreover, the loss of UL7 prevents viral reactivation in HPCs in vitro as well as in humanized mice. These observations define the first virally encoded differentiation factor with significant implications not only for HCMV reactivation but also for alteration of the hematopoietic compartment in transplant patients.

Reactive oxygen species-induced parthanatos of immunocytes by human cytomegalovirus-associated substance.

Previous studies have examined various immune evasion strategies of human cytomegalovirus (HCMV) to gain understanding of its pathogenesis. Although the mechanism that underlies immunocyte destruction near HCMV-infected lesions has yet to be established, it is here shown that substances produced by HCMV-infected cells induce death in several types of immunocytes, but not in fibroblasts or astrocytomas. These substances contain HCMV proteins and were termed HCMV-associated insoluble substance (HCMVAIS). The mechanism by which HCMVAIS induces cell death was characterized to improve understanding the death of immunocytes near HCMV-infected lesions. HCMVAIS were found to trigger production of intracellular nicotinamide adenine dinucleotide phosphate oxidase-derived reactive oxygen species (ROS), resulting in cell death, this effect being reversed following treatment with ROS inhibitors. Cell death was not induced in splenocytes from NOX-2 knockout mice. It was hypothesized that DNA damage induced by oxidative stress initiates poly ADP-ribose polymerase-1 (PARP-1)-mediated cell death, or parthanatos. HCMVAIS-induced cell death is accompanied by PARP-1 activation in a caspase-independent manner, nuclear translocation of apoptosis-inducing factor (AIF), and DNA fragmentation, which are typical features of parthanatos. Treatment with an AIF inhibitor decreased the rate of HCMVAIS-induced cell death, this being confirmed by hematoxylin and eosin staining; cell death in most HCMV-positive foci in serial section samples of a large intestine with HCMV infection was TUNEL-positive, cleaved caspase 3-negative and CD45-positive. Taken together, these data suggest that HCMV inhibits local immune responses via direct killing of immunocytes near HCMV-infected cells through ROS-induced parthanatos by HCMVAIS.

Human Cytomegalovirus Utilizes a Nontraditional Signal Transducer and Activator of Transcription 1 Activation Cascade via Signaling through Epidermal Growth Factor Receptor and Integrins To Efficiently Promote the Motility, Differentiation, and Polarization of Infected Monocytes.

Human cytomegalovirus (HCMV) infects peripheral blood monocytes and triggers biological changes that promote viral dissemination and persistence. We have shown that HCMV induces a proinflammatory state in infected monocytes, resulting in enhanced monocyte motility and transendothelial migration, prolonged monocyte survival, and differentiation toward a long-lived M1-like macrophage phenotype. Our data indicate that HCMV triggers these changes, in the absence of de novo viral gene expression and replication, through engagement and activation of epidermal growth factor receptor (EGFR) and integrins on the surface of monocytes. We previously identified that HCMV induces the upregulation of multiple proinflammatory gene ontologies, with the interferon-associated gene ontology exhibiting the highest percentage of upregulated genes. However, the function of the HCMV-induced interferon (IFN)-stimulated genes (ISGs) in infected monocytes remained unclear. We now show that HCMV induces the enhanced expression and activation of a key ISG transcriptional regulator, signal transducer and activator of transcription (STAT1), via an IFN-independent but EGFR- and integrin-dependent signaling pathway. Furthermore, we identified a biphasic activation of STAT1 that likely promotes two distinct phases of STAT1-mediated transcriptional activity. Moreover, our data show that STAT1 is required for efficient early HCMV-induced enhanced monocyte motility and later for HCMV-induced monocyte-to-macrophage differentiation and for the regulation of macrophage polarization, suggesting that STAT1 may serve as a molecular convergence point linking the biological changes that occur at early and later times postinfection. Taken together, our results suggest that HCMV reroutes the biphasic activation of a traditionally antiviral gene product through an EGFR- and integrin-dependent pathway in order to help promote the proviral activation and polarization of infected monocytes.IMPORTANCE HCMV promotes multiple functional changes in infected monocytes that are required for viral spread and persistence, including their enhanced motility and differentiation/polarization toward a proinflammatory M1 macrophage. We now show that HCMV utilizes the traditionally IFN-associated gene product, STAT1, to promote these changes. Our data suggest that HCMV utilizes EGFR- and integrin-dependent (but IFN-independent) signaling pathways to induce STAT1 activation, which may allow the virus to specifically dictate the biological activity of STAT1 during infection. Our data indicate that HCMV utilizes two phases of STAT1 activation, which we argue molecularly links the biological changes that occur following initial binding to those that continue to occur days to weeks following infection. Furthermore, our findings may highlight a unique mechanism for how HCMV avoids the antiviral response during infection by hijacking the function of a critical component of the IFN response pathway.

Human Cytomegalovirus Requires Epidermal Growth Factor Receptor Signaling To Enter and Initiate the Early Steps in the Establishment of Latency in CD34+ Human Progenitor Cells.

The establishment of human cytomegalovirus (HCMV) latency and persistence relies on the successful infection of hematopoietic cells, which serve as sites of viral persistence and contribute to viral spread. Here, using blocking antibodies and pharmacological inhibitors, we document that HCMV activation of the epidermal growth factor receptor (EGFR) and downstream phosphatidylinositol 3-kinase (PI3K) mediates viral entry into CD34+ human progenitor cells (HPCs), resulting in distinct cellular trafficking and nuclear translocation of the virus compared to that in other immune cells, such as we have documented in monocytes. We argue that the EGFR allows HCMV to regulate the cellular functions of these replication-restricted cells via its signaling activity following viral binding. In addition to regulating HCMV entry/trafficking, EGFR signaling may also shape the early steps required for the successful establishment of viral latency in CD34+ cells, as pharmacological inhibition of EGFR increases the transcription of lytic IE1/IE2 mRNA while curbing the expression of latency-associated UL138 mRNA. EGFR signaling following infection of CD34+ HPCs may also contribute to changes in hematopoietic potential, as treatment with the EGFR kinase (EGFRK) inhibitor AG1478 alters the expression of the cellular hematopoietic cytokine interleukin 12 (IL-12) in HCMV-infected cells but not in mock-infected cells. These findings, along with our previous work with monocytes, suggest that EGFR likely serves as an important determinant of HCMV tropism for select subsets of hematopoietic cells. Moreover, our new data suggest that EGFR is a key receptor for efficient viral entry and that the ensuing signaling regulates important early events required for successful infection of CD34+ HPCs by HCMV.IMPORTANCE HCMV establishes lifelong persistence within the majority of the human population without causing overt pathogenesis in healthy individuals. Despite this, reactivation of HCMV from its latent reservoir in the bone marrow causes significant morbidity and mortality in immunologically compromised individuals, such as bone marrow and solid organ transplant patients. Lifelong persistent infection has also been linked with the development of various cardiovascular diseases in otherwise healthy individuals. Current HCMV therapeutics target lytic replication, but not the latent viral reservoir; thus, an understanding of the molecular basis for viral latency and persistence is paramount to controlling or eliminating HCMV infection. Here, we show that the viral signalosome activated by HCMV binding to its entry receptor, EGFR, in CD34+ HPCs initiates early events necessary for successful latent infection of this cell type. EGFR and associated signaling players may therefore represent promising targets for mitigating HCMV persistence.

Viral binding-induced signaling drives a unique and extended intracellular trafficking pattern during infection of primary monocytes.

We initiated experiments to examine the infection of monocytes postentry. New data show that human cytomegalovirus (HCMV) DNA is detected in the nucleus beginning only at 3 d postinfection in monocytes, compared with 30 min postinfection in fibroblasts and endothelial cells, suggesting that HCMV nuclear translocation in monocytes is distinct from that seen in other cell types. We now show that HCMV is initially retained in early endosomes and then moves sequentially to the trans-Golgi network (TGN) and recycling endosomes before nuclear translocation. HCMV is retained initially as a mature particle before deenvelopment in recycling endosomes. Disruption of the TGN significantly reduced nuclear translocation of viral DNA, and HCMV nuclear translocation in infected monocytes was observed only when correct gH/gL/UL128-131/integrin/c-Src signaling occurred. Taken together, our findings show that viral binding of the gH/gL/UL128-131 complex to integrins and the ensuing c-Src signaling drive a unique nuclear translocation pattern that promotes productive infection and avoids viral degradation, suggesting that it represents an additional viral evasion/survival strategy.

Human Cytomegalovirus Promotes Survival of Infected Monocytes via a Distinct Temporal Regulation of Cellular Bcl-2 Family Proteins.

UNLABELLED: Monocytes play a key role in the hematogenous dissemination of human cytomegalovirus (HCMV) to target organ systems. To infect monocytes and reprogram them to deliver infectious virus, HCMV must overcome biological obstacles, including the short life span of monocytes and their antiviral proapoptotic response to infection. We have shown that virally induced upregulation of cellular Mcl-1 promotes early survival of HCMV-infected monocytes, allowing cells to overcome an early apoptotic checkpoint at around 48 h postinfection (hpi). Here, we demonstrate an HCMV-dependent shift from Mcl-1 as the primary antiapoptotic player to the related protein, Bcl-2, later during infection. Bcl-2 was upregulated in HCMV-infected monocytes beginning at 48 hpi. Treatment with the Bcl-2 antagonist ABT-199 only reduced the prosurvival effects of HCMV in target monocytes beginning at 48 hpi, suggesting that Mcl-1 controls survival prior to 48 hpi, while Bcl-2 promotes survival after 48 hpi. Although Bcl-2 was upregulated following viral binding/signaling through cellular integrins (compared to Mcl-1, which is upregulated through binding/activation of epidermal growth factor receptor [EGFR]), it functioned similarly to Mcl-1, adopting the early role of Mcl-1 in preventing caspase-3 cleavage/activation. This distinct, HCMV-induced shift from Mcl-1 to Bcl-2 occurs in response to a cellular upregulation of proapoptotic Bax, as small interfering RNA (siRNA)-mediated knockdown of Bax reduced the upregulation of Bcl-2 in infected monocytes and rescued the cells from the apoptotic effects of Bcl-2 inhibition. Our data demonstrate a distinct survival strategy whereby HCMV induces a biphasic regulation of cellular Bcl-2 proteins to promote host cell survival, leading to viral dissemination and the establishment of persistent HCMV infection. IMPORTANCE: Hematogenous dissemination of HCMV via infected monocytes is a crucial component of the viral survival strategy and is required for the establishment of persistent infection and for viral spread to additional hosts. Our system of infected primary human blood monocytes provides us with an opportunity to answer specific questions about viral spread and persistence in in vivo-relevant myeloid cells that cannot be addressed with the more traditionally used replication-permissive cells. Our goal in examining the mechanisms whereby HCMV reprograms infected monocytes to promote viral dissemination is to uncover new targets for therapeutic intervention that would disrupt key viral survival and persistence strategies. Because of this important role in maintaining survival of HCMV-infected monocytes, our new data on the role of Bcl-2 regulation during viral infection represents a promising molecular target for mitigating viral spread and persistence.

Induction of PERV antigen in porcine peripheral blood mononuclear cells by human herpesvirus 1.

BACKGROUND: Xenotransplantation represents one of alternative candidates for allotransplantation due to the chronic shortage of suitable human tissues; however, many obstacles remain. Expression and release of endogenous retroviral antigens by porcine cells after transplantation may evoke adverse immune responses in human subjects. Here, we examined whether human herpesvirus 1 (HHV-1) could induce the production of porcine endogenous retrovirus (PERV) antigens in porcine peripheral blood mononuclear cells (PBMCs). METHODS: Porcine PBMCs were infected with HHV-1 and examined for the production of PERV Gag protein and HHV-1 using antigen-capture ELISA and quantitative real-time polymerase chain reaction (PCR), respectively. RESULTS: HHV-1 infection resulted in a 1.7- to 33.2-fold induction of PERV Gag relative to mock infection controls, compared to a 2.9- to 12.9-fold induction following treatment with PMA. Expression of PERV Gag was detected in porcine PBMCs and PK-15 cells after HHV-1 infection by double immunofluorescence staining of PERV Gag and HHV-1 antigen. The viability of HHV-1-infected porcine PBMCs was significantly lower than that of mock-infected cells. The HHV-1 level in the culture supernatant increased 5.2-fold relative to controls 24-h post-infection, indicative of active replication within these cells; decreased levels of HHV-1 were detected 72-h post-infection. CONCLUSIONS: These results suggest that HHV-1 may be capable of infecting transplanted porcine cells, resulting in strong direct induction of PERV antigen.

HCMV reprogramming of infected monocyte survival and differentiation: a Goldilocks phenomenon.

The wide range of disease pathologies seen in multiple organ sites associated with human cytomegalovirus (HCMV) infection results from the systemic hematogenous dissemination of the virus, which is mediated predominately by infected monocytes. In addition to their role in viral spread, infected monocytes are also known to play a key role in viral latency and life-long persistence. However, in order to utilize infected monocytes for viral spread and persistence, HCMV must overcome a number of monocyte biological hurdles, including their naturally short lifespan and their inability to support viral gene expression and replication. Our laboratory has shown that HCMV is able to manipulate the biology of infected monocytes in order to overcome these biological hurdles by inducing the survival and differentiation of infected monocytes into long-lived macrophages capable of supporting viral gene expression and replication. In this current review, we describe the unique aspects of how HCMV promotes monocyte survival and differentiation by inducing a "finely-tuned" macrophage cell type following infection. Specifically, we describe the induction of a uniquely polarized macrophage subset from infected monocytes, which we argue is the ideal cellular environment for the initiation of viral gene expression and replication and, ultimately, viral spread and persistence within the infected host.

Pulmonary thromboembolectomy for acute pulmonary thromboembolism.

BACKGROUND: Acute pulmonary thromboembolism is fatal because of abruptly occurring hypoxemia and right ventricular failure. There are several treatment modalities, including anticoagulation, thrombolytics, ECMO (extracorporeal membrane oxygenator), and thromboembolectomy, for managing acute pulmonary thromboembolism. MATERIALS AND METHODS: Medical records from January 1999 to December 2004 at our institution were retrospectively reviewed for pulmonary thromboembolectomy. There were 7 patients (4 men and 3 women), who underwent a total of 8 operations because one patient had post-operative recurrent emboli and underwent reoperation. Surgery was indicatedfor mild hypoxemia and performed with CPB (cardiopulmonary bypass) in a beating heart state. RESULTS: The patients had several symptoms, such as dyspnea, chest discomfort, and palpitation. Four patients had deep vein thromboembolisms and 3 had psychotic problems, specifically schizophrenia. Post-operative complications included hemothorax, pleural effusion, and pericardial effusion. There were two hospital deaths, one each by brain death and right heart failure. CONCLUSION: Emergency operation should be performed when medical treatments are no longer effective.

Human cytomegalovirus (HCMV) infection in osteosarcoma cell line suppresses GM-CSF production by induction of TGF-beta.

This study was performed to elucidate the possible mechanism of the disturbance of hemopoiesis by HCMV infection. Saos-2 cells constitutively express mRNA of GM-CSF, and its expression was profoundly decreased by HCMV infection, which required full replication of the virus and was mediated by soluble factors released from the HCMV-infected Saos-2 cells. TGF-beta1 production was statistically and significantly increased from one day after HCMV infection. Expression and production of GM-CSF in Saos-2 cells were restored when a culture supernatant of HCMV-infected Saos-2 cells was reacted with neutralizing anti-TGF-beta antibody. Conclusively, HCMV inhibits GM-CSF expression in Saos-2 cells partly by the increased production of TGF-beta1.

Human cytomegalovirus (HCMV) IE1 plays role in resistance to apoptosis with etoposide in cancer cell line by Cdk2 accumulation.

Human cytomegalovirus (HCMV) has many strategies to survive the attack of the host. HCMV infection of host cells induces cellular activation and disturbance of the cell cycle. It is possible that HCMV modulates the behavior of certain cancer cells that are susceptible to HCMV infection. This study was performed to identify the possible mechanism of resistance to apoptotic stimuli in some cancer cell lines by HCMV infection. HCMV-infected cancer cells showed resistance to apoptosis induced by the topoisomerase II inhibitor etoposide. UMG1-2, which constitutively expresses HCMV immediate-early protein-1 (IE1), had resistance to apoptosis induced by etoposide as compared with the parental cell line U373MG. Measurement of caspases activity with fluorogenic substrates in etoposide-treated U373MG and UMG1-2 cells and the direct activation of caspase-3 with peptides containing arginine-glycine-aspartate in U373MG and UMG1-2 cells revealed that the inhibition level of apoptosis by HCMV IE1 would be upstream of caspase-3 in the caspase cascade pathway. Cellular expression of Cdk2 was increased in UMG1- 2 after etoposide treatment while the expression of E2F-1 in UMG1-2 was decreased as compared with that in U373MG. The Cdk2 inhibitor, roscovitine, decreased the resistance to apoptosis on etoposide-treated UMG1-2. These results suggest that aberrant HCMV infection confers resistance to anticancer drugs on some cancer cells and protects cells from apoptosis, possibly due to the deregulation of cyclin-dependent kinase by HCMV immediate-early protein.