Biomedical subjects

S E Crawford

Publications and source records attributed to S E Crawford.

At least 19 recordsLinked to original sources

PubMed2006

Rotavirus proteins: structure and assembly.

Rotavirus is a major pathogen of infantile gastroenteritis. It is a large and complex virus with a multilayered capsid organization that integrates the determinants of host specificity, cell entry, and the enzymatic functions necessary for endogenous transcription of the genome that consists of 11 dsRNA segments. These segments encode six structural and six nonstructural proteins. In the last few years, there has been substantial progress in our understanding of both the structural and functional aspects of a variety of molecular processes involved in the replication of this virus. Studies leading to this progress using of a variety of structural and biochemical techniques including the recent application of RNA interference technology have uncovered several unique and intriguing features related to viral morphogenesis. This review focuses on our current understanding of the structural basis of the molecular processes that govern the replication of rotavirus.

Antigens, Viral↗

PubMed2006

Rotavirus NSP4 induces a novel vesicular compartment regulated by calcium and associated with viroplasms.

Rotavirus is a major cause of infantile viral gastroenteritis. Rotavirus nonstructural protein 4 (NSP4) has pleiotropic properties and functions in viral morphogenesis as well as pathogenesis. Recent reports show that the inhibition of NSP4 expression by small interfering RNAs leads to alteration of the production and distribution of other viral proteins and mRNA synthesis, suggesting that NSP4 also affects virus replication by unknown mechanisms. This report describes studies aimed at correlating the localization of intracellular NSP4 in cells with its functions. To be able to follow the localization of NSP4, we fused the C terminus of full-length NSP4 with the enhanced green fluorescent protein (EGFP) and expressed this fusion protein inducibly in a HEK 293-based cell line to avoid possible cytotoxicity. NSP4-EGFP was initially localized in the endoplasmic reticulum (ER) as documented by Endo H-sensitive glycosylation and colocalization with ER marker proteins. Only a small fraction of NSP4-EGFP colocalized with the ER-Golgi intermediate compartment (ERGIC) marker ERGIC-53. NSP4-EGFP did not enter the Golgi apparatus, in agreement with the Endo H sensitivity and a previous report that secretion of an NSP4 cleavage product generated in rotavirus-infected cells is not inhibited by brefeldin A. A significant population of expressed NSP4-EGFP was distributed in novel vesicular structures throughout the cytoplasm, not colocalizing with ER, ERGIC, Golgi, endosomal, or lysosomal markers, thus diverging from known biosynthetic pathways. The appearance of vesicular NSP4-EGFP was dependent on intracellular calcium levels, and vesicular NSP4-EGFP colocalized with the autophagosomal marker LC3. In rotavirus-infected cells, NSP4 colocalized with LC3 in cap-like structures associated with viroplasms, the site of nascent viral RNA replication, suggesting a possible new mechanism for the involvement of NSP4 in virus replication.

Calcium↗

PubMed2001

Thrombospondin-1, vascular endothelial growth factor and fibroblast growth factor-2 are key functional regulators of angiogenesis in the prostate.

BACKGROUND: Prostate cells secrete many molecules capable of regulating angiogenesis; however, which of these actually function as essential regulators of neovascularization is not yet clear. METHODS: Functional angiogenic mediators secreted by normal and diseased prostate cells were identified using an in vitro angiogenesis assay. These factors were quantified by immunoblot or ELISA and localized in tissue by immunohistochemistry. RESULTS: Normal prostate epithelial cell secretions were anti-angiogenic due to inhibitory thrombospondin-1 (TSP-1) whereas this inhibitor was decreased in the pro-angiogenic secretions derived from benign prostatic hyperplasia (BPH) and cancer cells. This pro-angiogenic activity depended primarily on fibroblast growth factor-2 (FGF-2) and/or vascular endothelial growth factor (VEGF) whose secretion was increased. Immunolocalization studies confirmed that the changes detected in vitro also occurred in vivo. CONCLUSIONS: During disease progression in the prostate, production of TSP-1, the major inhibitor, is down-regulated while that of stimulatory FGF-2 and/or VEGF rise, leading to the induction of the new vessels necessary to support tumor growth.

Adolescent↗

PubMed2001

CD8 T lymphocytes and macrophages infiltrate coronary artery aneurysms in acute Kawasaki disease.

The pathogenesis of coronary arterial inflammation in acute Kawasaki disease (KD) is unclear. To test the hypothesis that the KD vascular lesion is an activated T lymphocyte-dependent process, immunohistochemical studies were done on coronary artery aneurysms from 8 fatal acute KD cases by using antibodies to CD45RO (activated or memory T lymphocyte), CD8 (cytotoxic T lymphocyte), CD4 (helper T lymphocyte), HAM56 (macrophage), and CD20 (B lymphocyte). Acute KD coronary arteritis was characterized by transmural infiltration of CD45RO T lymphocytes with CD8 T lymphocytes predominating over CD4 T lymphocytes. Macrophages were present primarily in the adventitial layer; B lymphocytes were notably absent. These data lend support to the hypotheses that KD results from infection with an intracellular pathogen, such as a virus, whose antigens are presented by major histocompatibility complex class I molecules, and that CD8 T lymphocytes and macrophages are important in the pathogenesis of KD coronary aneurysms.

Antigens, CD20↗

PubMed2001

Prevention of ischemia-induced retinopathy by the natural ocular antiangiogenic agent pigment epithelium-derived factor.

Aberrant blood vessel growth in the retina that underlies the pathology of proliferative diabetic retinopathy and retinopathy of prematurity is the result of the ischemia-driven disruption of the normally antiangiogenic environment of the retina. In this study, we show that a potent inhibitor of angiogenesis found naturally in the normal eye, pigment epithelium-derived growth factor (PEDF), inhibits such aberrant blood vessel growth in a murine model of ischemia-induced retinopathy. Inhibition was proportional to dose and systemic delivery of recombinant protein at daily doses as low as 2.2 mg/kg could prevent aberrant endothelial cells from crossing the inner limiting membrane. PEDF appeared to inhibit angiogenesis by causing apoptosis of activated endothelial cells, because it induced apoptosis in cultured endothelial cells and an 8-fold increase in apoptotic endothelial cells could be detected in situ when the ischemic retinas of PEDF-treated animals were compared with vehicle-treated controls. The ability of low doses of PEDF to curtail aberrant growth of ocular endothelial cells without overt harm to retinal morphology suggests that this natural protein may be beneficial in the treatment of a variety of retinal vasculopathies.

Angiogenesis Inhibitors↗

PubMed2001

Pathogenesis of rotavirus gastroenteritis.

The outcome of intestinal infection with rotaviruses is more complex than initially appreciated, and it is affected by a complex interplay of host and viral factors. Rotaviruses infect intestinal enterocytes, and the early events in infection are mediated by virus-epithelial cell interactions. Diarrhoea may be caused by several mechanisms including (i) malabsorption that occurs secondary to the destruction of enterocytes, (ii) villus ischaemia and activation of the enteric nervous system that may be evoked by release of a vasoactive agent from infected epithelial cells in the absence of significant pathologic lesions or enterocyte damage, and (iii) intestinal secretion stimulated by the intracellular or extracellular action of the rotavirus non-structural protein, NSP4, a novel enterotoxin and secretory agonist with pleiotropic properties. New studies of rotavirus infection of polarized intestinal epithelial cells show that rotaviruses infect cells differently depending on whether or not they require sialic acid for initial binding, and infection alters epithelial cell functions. NSP4 also affects epithelial cell function and interactions. NSP4 (i) induces an age- and dose-dependent diarrhoeal response in young rodents that is similar to virus-induced disease, (ii) stimulates a Ca(2+)-dependent cell permeability where the secretory response is age-dependent, and (iii) alters epithelial cell integrity. Antibody to NSP4 protects mouse pups from diarrhoea induced by homotypic and heterotypic viruses. These data support a new mechanism of rotavirus-induced diarrhoea whereby a viral enterotoxin triggers a signal transduction pathway that alters epithelial cell permeability and chloride secretion. This new information about how a gastrointestinal virus causes disease demonstrates common pathogenic mechanisms for viral and bacterial pathogens not previously appreciated. These results also suggest new approaches to prevent or treat rotavirus-induced diarrhoea.

Animals↗

PubMed2001

Nonadherence is associated with late rejection in pediatric heart transplant recipients.

OBJECTIVES: The objective was to study the impact of nonadherence on late rejection after pediatric heart transplantation. STUDY DESIGN: This was a retrospective cohort study of cardiac transplant recipients surviving >6 months (n = 50). Patients were stratified by episodes of late rejection. End points were defined by cyclosporin A (CSA) level, CSA level variability, and patient admission of nonadherence. RESULTS: In 15 patients there were 49 episodes of late rejection, and 37 (76%) were associated with nonadherence. Of these patients, 7 of 15 died, and 3 of 15 had transplant coronary artery disease. Risk factors for the rejection were single-parent home, non-white, older age, and higher CSA level variability. In 35 nonrejectors there were 4 deaths from sepsis, post-transplant lymphoproliferative disease, renal failure, and encephalomyelitis. CONCLUSION: Late rejection after pediatric heart transplantation is associated with nonadherence, is common during adolescence, and is associated with poor outcome.

Adolescent↗

PubMed2001

Healing of a free tracheal autograft is enhanced by topical vascular endothelial growth factor in an experimental rabbit model.

OBJECTIVE: In 1996, we introduced the free tracheal autograft technique for repair of congenital tracheal stenosis from complete tracheal rings in infants and children. Sources of possible concern with this procedure include the potential for autograft ischemia, patch dehiscence, and recurrent stenosis. Vascular endothelial growth factor is a potent angiogenic inducer (particularly in the setting of ischemia, hypoxia, or both) and is postulated to promote tissue healing. The purpose of this study was to test the hypothesis that pretreatment of tracheal autografts with topical vascular endothelial growth factor would enhance tracheal healing. METHODS: In a rabbit model of tracheal reconstruction (n = 32), an elliptically shaped portion of the anterior tracheal wall was excised. The excised portion of trachea was one third of the tracheal circumference and 2 cm in length (6 tracheal rings). This portion of trachea (the autograft) was soaked in either vascular endothelial growth factor (5 microg/mL, n = 16) or normal saline solution (n = 16) for 15 minutes before being reimplanted in the resultant tracheal opening. Animals were killed and autografts were examined at 2 weeks, 1 month, and 2 months postoperatively for gross and microscopic characteristics. RESULTS: By 2 weeks, and progressing through 1 and 2 months, autografts treated with vascular endothelial growth factor, as compared with control autografts, had reduced luminal stenosis, submucosal fibrosis, and inflammatory infiltrate (P <.05). The autografts tended to become malaligned in control animals, whereas the tracheal architecture was preserved in rabbits treated with vascular endothelial growth factor. Microvascular vessel density was significantly greater in all vascular endothelial growth factor groups (P <.05) at all time intervals. CONCLUSIONS: Topical treatment of free tracheal autografts with vascular endothelial growth factor in a rabbit tracheal reconstruction model enhanced healing, as evidenced by accelerated autograft revascularization, reduced submucosal fibrosis and inflammation, and preservation of the normal tracheal architecture. Topical vascular endothelial growth factor may improve future results of tracheal reconstruction.

Administration, Cutaneous↗

PubMed2001

Trypsin cleavage stabilizes the rotavirus VP4 spike.

Trypsin enhances rotavirus infectivity by an unknown mechanism. To examine the structural basis of trypsin-enhanced infectivity in rotaviruses, SA11 4F triple-layered particles (TLPs) grown in the absence (nontrypsinized rotavirus [NTR]) or presence (trypsinized rotavirus [TR]) of trypsin were characterized to determine the structure, the protein composition, and the infectivity of the particles before and after trypsin treatment. As expected, VP4 was not cleaved in NTR particles and was cleaved into VP5(*) and VP8(*) in TR particles. However, surprisingly, while the VP4 spikes were clearly visible and well ordered in the electron cryomicroscopy reconstructions of TR TLPs, they were totally absent in the reconstructions of NTR TLPs. Biochemical analysis with radiolabeled particles indicated that the stoichiometry of the VP4 in NTR particles was the same as that in TR particles and that the VP8(*) portion of NTR, but not TR, particles is susceptible to further proteolysis by trypsin. Taken together, these structural and biochemical data show that the VP4 spikes in the NTR TLPs are icosahedrally disordered and that they are conformationally different. Structural studies on the NTR TLPs after trypsin treatment showed that spike structure could be partially recovered. Following additional trypsin treatment, infectivity was enhanced for both NTR and TR particles, but the infectivity of NTR remained 2 logs lower than that of TR particles. Increased infectivity in these particles corresponded to additional cleavages in VP5(*), at amino acids 259, 583, and putatively 467, which are conserved in all P serotypes of human and animal group A rotaviruses and also corresponded with a structural change in VP7. These biochemical and structural results show that trypsin cleavage imparts order to VP4 spikes on de novo synthesized virus particles, and these ordered spikes make virus entry into cells more efficient.

Amino Acid Sequence↗

PubMed2001

Differential infection of polarized epithelial cell lines by sialic acid-dependent and sialic acid-independent rotavirus strains.

Infection of epithelial cells by some animal rotaviruses, but not human or most animal rotaviruses, requires the presence of N-acetylneuraminic (sialic) acid (SA) on the cell surface for efficient infectivity. To further understand how rotaviruses enter susceptible cells, six different polarized epithelial cell lines, grown on permeable filter membrane supports containing 0.4-microm pores, were infected apically or basolaterally with SA-independent or SA-dependent rotaviruses. SA-independent rotaviruses applied apically or basolaterally were capable of efficiently infecting both sides of the epithelium of all six polarized cell lines tested, while SA-dependent rotaviruses only infected efficiently through the apical surface of five of the polarized cell lines tested. Regardless of the route of virus entry, SA-dependent and SA-independent rotaviruses were released almost exclusively from the apical domain of the plasma membrane of polarized cells before monolayer disruption or cell lysis. The transepithelial electrical resistance (TER) of cells decreased at the same time, irrespective of whether infection with SA-independent rotaviruses occurred apically or basolaterally. The TER of cells infected apically with SA-dependent rotaviruses decreased earlier than that of cells infected basolaterally. Rotavirus infection decreased TER before the appearance of cytopathic effect and cell death and resulted in an increase in the paracellular permeability to [(3)H]inulin as a function of loss of TER. The presence of SA residues on either the apical or basolateral side was determined using a Texas Red-conjugated lectin, wheat germ agglutinin (WGA), which binds SA residues. WGA bound exclusively to SA residues on the apical surface of the cells, confirming the requirement for SA residues on the apical cell membrane for efficient infectivity of SA-dependent rotaviruses. These results indicate that the rotavirus SA-independent cellular receptor is present on both sides of the epithelium, but SA-dependent and SA-independent rotavirus strains infect polarized epithelial cells by different mechanisms, which may be relevant for pathogenesis and selection of vaccine strains. Finally, rotavirus-induced alterations of the epithelial barrier and paracellular permeability suggest that common mechanisms of pathogenesis may exist between viral and bacterial pathogens of the intestinal tract.

Animals↗

PubMed2001

Pigment epithelium-derived factor (PEDF) in neuroblastoma: a multifunctional mediator of Schwann cell antitumor activity.

Neuroblastoma is notable for its cellular heterogeneity and unpredictable outcome. Tumors are a variable mixture of primitive malignant neuroblasts, more differentiated ganglionic cells, Schwann and endothelial cells. Although often fatal, neuroblastomas can spontaneously regress, possibly due to favorable autocrine and paracrine interactions among these cells. Here, pigment epithelium-derived factor (PEDF), a potent inhibitor of angiogenesis and inducer of neural differentiation, is shown to be produced by ganglionic cells and Schwann cells, but not by more primitive tumor cells. Although undifferentiated neuroblastoma tumor cell secretions were angiogenic primarily due to vascular endothelial growth factor, secretions of Schwann cells were anti-angiogenic due to PEDF. In addition, PEDF was the major factor responsible for Schwann cell's ability to induce tumor cell differentiation in vitro and recombinant PEDF had the same effect in vitro and in vivo. Both the growth and the survival of Schwann cells were enhanced by PEDF. Thus PEDF may serve as a multifunctional antitumor agent in neuroblastomas, inhibiting angiogenesis while promoting the numbers of Schwann cells and differentiated tumor cells that in turn produce PEDF, suggesting that its clinical administration could stimulate a multifaceted antitumor feedback loop with the potential to limit and possibly regress tumor growth.

Angiogenesis Inhibitors↗

PubMed2000

IgA plasma cell infiltration of proximal respiratory tract, pancreas, kidney, and coronary artery in acute Kawasaki disease.

The etiology and pathogenesis of Kawasaki disease (KD) remain unknown. As previously reported, in US patients with acute KD, IgA plasma cells (PCs) infiltrate the vascular wall. To determine whether IgA PCs are increased at mucosal sites in KD and to determine whether other nonvascular KD tissues are infiltrated by IgA PCs, the cells were immunolocalized and quantitated in tissue sections taken from 18 US and Japanese patients who died of acute KD and from 10 age-matched controls. IgA PCs were significantly increased in the trachea of patients who died of acute KD, compared with controls (P<.01), a finding that was similar to findings in children with fatal respiratory viral infection. IgA PCs also infiltrated coronary artery, pancreas, and kidney in all KD patients. These findings strongly support entry of the KD etiologic agent through the upper respiratory tract, resulting in an IgA immune response, with systemic spread to vascular tissue, pancreas, and kidney.

Acute Disease↗

PubMed2000

Reversal of severe late left ventricular failure after pediatric heart transplantation and possible role of plasmapheresis.

Late acute cardiac graft failure carries a high mortality in adults. Vascular mediators and factors other than classic T-cell-mediated rejection may play a role in this process, and aggressive multimodality therapy may improve survival. We report experience with plasmapheresis in treating late severe acute left ventricular dysfunction in a group of pediatric heart transplant recipients. We retrospectively reviewed clinical records, echocardiograms, hemodynamics, coronary angiograms, biopsy specimens, and treatment regimens for 5 patients with 7 episodes of late-onset severe graft failure who recovered. Plasmapheresis was applied in all cases, in addition to methylprednisolone, cyclophosphamide, lympholytic agents, and aggressive supportive care including mechanical ventilation and hemofiltration. All patients presented with acute severe left ventricular dysfunction 1.4 to 7.9 years (mean 3.6) after orthotopic heart transplantation. Mean shortening fraction at presentation was 13 to 23% (mean 16), initial endomyocardial biopsy specimens were grade 0 to 3B, and immunofluorescence studies were negative. Treatment included plasmapheresis, cyclophosphamide, mechanical ventilation, hemofiltration, and inotropes. Clinical recovery was slow, with 4 to 8 weeks until left ventricular function normalized, and 2.2 to 9.4 (mean 4.6) weeks to hospital discharge. At follow-up (50 to 38 months, mean 24), all are alive. Two patients are well, whereas coronary vasculopathy developed in 3. Thus, survival may improve in patients with late graft failure with low biopsy score and plasmapheresis combined with multimodality therapy.

Adolescent↗

PubMed2000

Dexamethasone reduces the inflammatory response to cardiopulmonary bypass in children.

BACKGROUND: A randomized, prospective, double-blind study of 29 children was performed to evaluate the hypothesis that dexamethasone administration prior to cardiopulmonary bypass would decrease the inflammatory mediator release and improve the postoperative clinical course. METHODS: Fifteen children received dexamethasone (1 mg/kg intravenously) and 14 (controls) received saline solution 1 hour prior to CPB. Serial blood analyses for interleukin-6, tumor necrosis factor-alpha, complement component C3a, and absolute neutrophil count were performed. Postoperative variables evaluated included temperature, supplemental fluids, alveolar-arterial oxygen gradient, and days of mechanical ventilation. RESULTS: Dexamethasone caused an eightfold decrease in interleukin-6 levels and a greater than threefold decrease in tumor necrosis factor-alpha levels after CPB (p < 0.05). Complement component C3a and absolute neutrophil count were not affected by dexamethasone. The mean rectal temperature for the first 24 hours postoperatively was significantly lower in the group given dexamethasone than in the controls (37.2 degrees +/- 0.4 degrees C versus 37.7 degrees +/- 4 degrees C; p = 0.007). Dexamethasone-treated patients required less supplemental fluid during the first 48 hours (22 +/- 28 mL/kg versus 47 +/- 34 mL/kg; p = 0.04). Compared with controls, dexamethasone-treated children had significantly lower alveolar-arterial oxygen gradients during the first 24 hours (144 +/- 108 mm Hg versus 214 +/- 118 mm Hg; p = 0.02) and required less mechanical ventilation (median duration, 3 days versus 5 days; p = 0.02). CONCLUSIONS: Dexamethasone administration prior to CPB in children leads to a reduction in the postbypass inflammatory response as assessed by cytokine levels and clinical course.

Anti-Inflammatory Agents↗

PubMed2000

Signals leading to apoptosis-dependent inhibition of neovascularization by thrombospondin-1.

Thrombospondin-1 (TSP-1) is a naturally occurring inhibitor of angiogenesis that limits vessel density in normal tissues and curtails tumor growth. Here, we show that the inhibition of angiogenesis in vitro and in vivo and the induction of apoptosis by thrombospondin-1 all required the sequential activation of CD36, p59fyn, caspase-3 like proteases and p38 mitogen-activated protein kinases. We also detected increased endothelial cell apoptosis in situ at the margins of tumors in mice treated with thrombospondin-1. These results indicate that thrombospondin-1, and possibly other broad-spectrum natural inhibitors of angiogenesis, act in vivo by inducing receptor-mediated apoptosis in activated microvascular endothelial cells.

Angiostatins↗

PubMed2000

Gata3 loss leads to embryonic lethality due to noradrenaline deficiency of the sympathetic nervous system.

Mouse embryos deficient in Gata3 die by 11 days post coitum (d.p.c.) from pathology of undetermined origin. We recently showed that Gata3-directed lacZ expression of a 625-kb Gata3 YAC transgene in mice mimics endogenous Gata3 expression, except in thymus and the sympathoadrenal system. As this transgene failed to overcome embryonic lethality (unpublished data and ref. 3) in Gata3-/- mice, we hypothesized that a neuroendocrine deficiency in the sympathetic nervous system (SNS) might cause embryonic lethality in these mutants. We find here that null mutation of Gata3 leads to reduced accumulation of Th (encoding tyrosine hydroxylase, Th) and Dbh (dopamine beta-hydroxylase, Dbh) mRNA, whereas several other SNS genes are unaffected. We show that Th and Dbh deficiencies lead to reduced noradrenaline in the SNS, and that noradrenaline deficiency is a proximal cause of death in mutants by feeding catechol intermediates to pregnant dams, thereby partially averting Gata3 mutation-induced lethality. These older, pharmacologically rescued mutants revealed abnormalities that previously could not be detected in untreated mutants. These late embryonic defects include renal hypoplasia and developmental defects in structures derived from cephalic neural crest cells. Thus we have shown that Gata3 has a role in the differentiation of multiple cell lineages during embryogenesis.

Animals↗

PubMed2000

Intranasal administration of 2/6-rotavirus-like particles with mutant Escherichia coli heat-labile toxin (LT-R192G) induces antibody-secreting cell responses but not protective immunity in gnotobiotic pigs.

We investigated the immunogenicity of recombinant double-layered rotavirus-like particle (2/6-VLPs) vaccines derived from simian SA11 or human (VP6) Wa and bovine RF (VP2) rotavirus strains. The 2/6-VLPs were administered to gnotobiotic pigs intranasally (i.n.) with a mutant Escherichia coli heat-labile toxin, LT-R192G (mLT), as mucosal adjuvant. Pigs were challenged with virulent Wa (P1A[8],G1) human rotavirus at postinoculation day (PID) 21 (two-dose VLP regimen) or 28 (three-dose VLP regimen). In vivo antigen-activated antibody-secreting cells (ASC) (effector B cells) and in vitro antigen-reactivated ASC (derived from memory B cells) from intestinal and systemic lymphoid tissues (duodenum, ileum, mesenteric lymph nodes [MLN], spleen, peripheral blood lymphocytes [PBL], and bone marrow lymphocytes) collected at selected times were quantitated by enzyme-linked immunospot assays. Rotavirus-specific immunoglobulin M (IgM), IgA, and IgG ASC and memory B-cell responses were detected by PID 21 or 28 in intestinal and systemic lymphoid tissues after i.n. inoculation with two or three doses of 2/6-VLPs with or without mLT. Greater mean numbers of virus-specific ASC and memory B cells in all tissues prechallenge were induced in pigs inoculated with two doses of SA11 2/6-VLPs plus mLT compared to SA11 2/6-VLPs without mLT. After challenge, anamnestic IgA and IgG ASC and memory B-cell responses were detected in intestinal lymphoid tissues of all VLP-inoculated groups, but serum virus-neutralizing antibody titers were not significantly enhanced compared to the challenged controls. Pigs inoculated with Wa-RF 2/6-VLPs (with or without mLT) developed higher anamnestic IgA and IgG ASC responses in ileum after challenge compared to pigs inoculated with SA11 2/6-VLPs (with or without mLT). Three doses of SA 11 2/6-VLP plus mLT induced the highest mean numbers of IgG memory B cells in MLN, spleen, and PBL among all groups postchallenge. However, no significant protection against diarrhea or virus shedding was evident in any of the 2/6-VLP (with or without mLT)-inoculated pigs after challenge with virulent Wa human rotavirus. These results indicate that 2/6-VLP vaccines are immunogenic in gnotobiotic pigs when inoculated i.n. and that the adjuvant mLT enhanced their immunogenicity. However, i.n. inoculation of gnotobiotic pigs with 2/6-VLPs did not confer protection against human rotavirus challenge.

Animals↗

PubMed2000

Serum vascular endothelial growth factor is elevated in cystic fibrosis and decreases with treatment of acute pulmonary exacerbation.

Chronic bacterial infection and neutrophilic inflammation characterize cystic fibrosis (CF) pulmonary disease. In many disorders, inflammation and angiogenesis are codependent phenomena. We previously noted excessive angiogenesis in CF tissues and elevated vascular endothelial growth factor (VEGF) in random serum samples from subjects with CF. To further explore this finding, we measured serum VEGF in 38 subjects with stable CF and in 25 subjects with other pulmonary diseases. Mean VEGF was elevated in both groups compared with reference values, but it was higher in CF: 403 +/- 280 versus 255 +/- 169 pg/ml, p = 0.02. VEGF was negatively correlated with FEV(1) in CF, r = -0.51, p = 0.007. To assess the effect of airway infection on VEGF, 10 subjects with CF were studied before and after intravenous antibiotic therapy for pulmonary exacerbation. VEGF levels decreased with antibiotic therapy, from 537 +/- 220 to 259 +/- 176 pg/ml, p = 0.001. We conclude that circulating VEGF is increased in subjects with CF and other inflammatory pulmonary disorders. In CF, VEGF elevation is related to airway infection. We speculate that increased circulating VEGF is related to chronic inflammation, which is robust in CF. Elevated circulating VEGF may result in tissue angiogenesis, furthering the progression of pulmonary disease.

Adolescent↗