Evidence of local adaptation in plant virus effects on host-vector interactions.

Recent research suggests that plant viruses, and other pathogens, frequently alter host-plant phenotypes in ways that facilitate transmission by arthropod vectors. However, many viruses infect multiple hosts, raising questions about whether these pathogens are capable of inducing transmission-facilitating phenotypes in phylogenetically divergent host plants and the extent to which evolutionary history with a given host or plant community influences such effects. To explore these issues, we worked with two newly acquired field isolates of cucumber mosaic virus (CMV)-a widespread multi-host plant pathogen transmitted in a non-persistent manner by aphids-and explored effects on the phenotypes of different host plants and on their subsequent interactions with aphid vectors. An isolate collected from cultivated squash fields (KVPG2-CMV) induced in the native squash host (Cucurbita pepo) a suite of effects on host-vector interactions suggested by previous work to be conducive to transmission (including reduced host-plant quality for aphids, rapid aphid dispersal from infected to healthy plants, and enhanced aphid attraction to the elevated emission of a volatile blend similar to that of healthy plants). A second isolate (P1-CMV) collected from cultivated pepper (Capsicum annuum) induced more neutral effects in its native host (largely exhibiting non-significant trends in the direction of effects seen for KVPG2-CMV in squash). When we attempted cross-host inoculations of these two CMV isolates (KVPG2-CMV in pepper and P1-CMV in squash), P1-CMV was only sporadically able to infect the novel host; KVPG2-CMV infected the novel pepper host with somewhat reduced success compared with its native host and reached virus titers significantly lower than those observed for either strain in its native host. Furthermore, KVPG2-CMV induced changes in the phenotype of the novel host, and consequently in host-vector interactions, dramatically different than those observed in the native host and apparently maladaptive with respect to virus transmission (e.g., host plant quality for aphids was significantly improved in this instance, and aphid dispersal was reduced). Taken together, these findings provide evidence of adaption by CMV to local hosts (including reduced infectivity and replication in novel versus native hosts) and further suggest that such adaptation may extend to effects on host-plant traits mediating interactions with aphid vectors. Thus, these results are consistent with the hypothesis that virus effects on host-vector interactions can be adaptive, and they suggest that multi-host pathogens may exhibit adaptation with respect to these and other effects on host phenotypes, perhaps especially in homogeneous monocultures.

Incidence of venous thromboembolism after elective knee arthroscopic surgery: a historical cohort study.

BACKGROUND: The incidence of symptomatic venous thromboembolism (VTE) after knee arthroscopy is uncertain. OBJECTIVES: To estimate the incidence of symptomatic VTE after arthroscopic knee surgery. METHODS: In a population-based historical cohort study, all Olmsted County, MN, USA, residents undergoing a first arthroscopic knee surgery during the 18-year period of 1988-2005 were followed for incident deep venous thrombosis or pulmonary embolism. The cumulative incidence of VTE after knee arthroscopy was determined using the Kaplan-Meier product limit estimator. Patient age at surgery, sex, calendar year of surgery, body mass index, anesthesia characteristics, and hospitalization were tested as potential predictors of VTE using Cox proportional hazards modeling, both univariately and adjusted for age and sex. RESULTS: Among 4833 Olmsted County residents with knee arthroscopy, 18 developed postoperative VTE, all within the first 6 weeks after surgery. The cumulative incidence rates of symptomatic VTE at 7, 14, and 35 days were 0.2%, 0.3%, and 0.4%, respectively. The hazard for postoperative VTE was significantly increased for older patient age (hazard ratio = 1.34 for each 10-year increase in patient age; P = 0.03) and hospitalization either before or after knee arthroscopy (hazard ratio = 14.1; P < 0.001). CONCLUSIONS: The incidence of symptomatic VTE after arthroscopic knee surgery is very low. Older age and hospitalization are associated with increased risk. Routine prophylaxis to prevent symptomatic VTE is likely not needed in this patient population.

The decision to accept treatment for osteoporosis following hip fracture: exploring the woman's perspective using a stage-of-change model.

Despite the availability of medications that reduce fracture risk, most women who sustain a hip fracture are not evaluated or treated for osteoporosis. While a number of studies have attributed this to a lack of physician awareness, no studies have evaluated this problem from the patient's perspective. To explore the process a woman negotiates when deciding to accept pharmacologic treatment for osteoporosis after hip fracture, we used a stage-of-change model to characterize a consecutive series of 70 postmenopausal women (mean age 85 years) admitted to a tertiary care hospital with an acute low-impact hip fracture between May 2000 and August 2000. We measured stage-of-change using a modified form of the Weinstein Precaution Adoption Process Model (PAPM). The majority of patients (65%) were ineligible because of dementia or delirium; only 29 were eligible and 21 were enrolled. Most women (62%) were in stages 1 or 2 of the PAPM, indicating that they were unaware of osteoporosis or had never considered pharmacologic treatment for it. The only factors associated with a more advanced PAPM stage (indicating active consideration or currently taking treatment) were a previous bone mineral density (BMD) evaluation ( p = 0.007) and a diagnosis of osteoporosis ( p = 0.001). Although 48% of women had a previous fragility fracture and osteoporosis knowledge was poor overall (mean score 52% correct), neither was associated with a more advanced PAPM stage in this sample. In conclusion, women evaluated after hip fracture were not ready to accept pharmacologic treatment for osteoporosis; they were unaware that they had osteoporosis or had never considered treatment for it. For a woman to advance through the behavior change process, she must first be made aware of the problem that requires a change in behavior. Physicians play a crucial role in promoting awareness of the diagnosis of osteoporosis after fracture, which in turn is associated with patient advancement through the behavior change process and the decision to accept pharmacologic intervention. The large number of cognitively impaired patients in this population, however, will certainly make efforts to improve osteoporosis awareness, diagnosis and intervention more challenging.

Low multiplicity cytomegalovirus infection of human aortic smooth muscle cells increases levels of major histocompatibility complex class I antigens and induces a proinflammatory cytokine milieu in the absence of cytopathology.

BACKGROUND: Cytomegalovirus has been implicated in the development of allograft vasculopathy in heart transplant recipients. Given that allograft vasculopathy is a form of chronic rejection, it is conceivable that cytomegalovirus somehow alters the allogeneic response to the vasculature. Prior work has demonstrated that smooth muscle cells (SMCs) are highly permissive for cytomegalovirus and exhibit cytopathologic characteristics and alterations in MHC class I antigens in response to cytomegalovirus at a high multiplicity of infection (MOI). METHODS: To determine whether cytomegalovirus at low, more clinically relevant MOI, can alter SMCs phenotypically, human aortic SMCs were infected with approximately 1 plaque forming units/3000 cells of cytomegalovirus strain AD169. RESULTS: One week after infection, human aortic SMCs (compared with human foreskin fibroblasts) demonstrated no cytopathologic characteristics (n = 6), released reduced amounts of intact virion into the culture media (assessed by exposing naive monolayers of human foreskin fibroblasts to media and staining for cytomegalovirus immediate-early antigen, n = 3), yet had at least, if not greater detectable total cytomegalovirus vital DNA levels. Infected HASMCs uniformly increased their expression of MHC class I antigen by 55% +/- 21% above constitutive levels (assessed by flow cytometry (n = 5, p < 0.0001). Cytomegalovirus infection resulted in an increase in interleukin-6 mRNA expression compared to control (297 +/- 63 vs 188 +/- 50, respectively; p = 0.02, n = 6) and reduced the expression of transforming growth factor-beta mRNA (802 +/- 152 vs 1201 +/- 236, respectively; p = 0.05). CONCLUSIONS: These data suggest that low MOI of cytomegalovirus can infect SMCs without producing cell cytolysis and, in spite of this lack of overt infection, modulate cell surface antigens and cytokine mRNA levels that can influence allogeneic responses.

Cardiac allograft vasculopathy: IgM antibody responses to donor-specific vascular endothelium.

We have previously demonstrated that heightened cell-mediated immunity to donor-specific endothelium was associated with an increased incidence of cardiac allograft vasculopathy (CAV) at 1 year postcardiac transplantation. We further demonstrated that the development of IgG antibody directed to donor-specific HLA antigens was extremely uncommon and, furthermore, had no relationship to the development of CAV. Subsequent studies have demonstrated a correlation between IgM antibody directed against endothelial cell antigens and the development of CAV. Accordingly, recipient serum obtained between 6 and 8 weeks (early) and 1 year (late) after transplantation were reacted with recombinant human interferon (rhIFN)-gamma pretreated donor-specific human aortic endothelial cells (HAECs) in 10 recipients with and 10 recipients without CAV at 1 year after transplantation. HAEC IgM binding was assessed by flow cytometry and complement fixation and HAEC lysis was measured using standard chromium release assays. Seven of 10 and 5 of 10 patients with CAV had IgM detected by flow at early and late time points, respectively (14+/-2 and 16+/-5 mean channel shift), whereas 5 of 10 and 6 of 10 patients without CAV had IgM detected by flow at early and late time points, respectively (15+/-4 and 14+/-3 mean channel shift). This finding was not different between groups. Despite between 50% and 70% of all patients having detectable IgM binding to ECs, no patient's serum was cytotoxic to its donor-specific HAECs. We conclude that IgM antibody to endothelial cells is common (at low titers) after transplantation. This antibody is not cytotoxic and in this study provided no discrimination between those with and without chronic rejection.

[Pars plana implantation of a ganciclovir drug carrier in patients with cytomegalovirus retinitis and AIDS. Indications, follow-up and postoperative complications]. / Pars-plana-Implantation eines Ganciclovir-Medikamententrägers bei Patienten mit Zytomegalievirusretinitis und AIDS. Indikation, Krankheitsverlauf und postoperative Komplikationen.

UNLABELLED: We performed an open clinical trial to assess the safety and efficacy of a 1 microgram/h ganciclovir implant for the treatment of newly and pretreated cytomegalovirus (CMV) retinitis in patients with the acquired immunodeficiency syndrome (AIDS). PATIENTS AND METHODS: Thirty-two eyes (20 patients) received the ganciclovir intraocular device and were prospectively followed up from 30 to 365 days. We used a modified technique for fixation of the device in half of the patients. The modification improved the fixation of the implant with a two-hole technique in the strut. RESULTS: Thirty eyes showed stabilization of the retinitis over the time, but in two patients resistance against ganciclovir and other nucleoside analogue compounds developed. Postoperative complications included vitreous hemorrhage (n = 1), cataract (n = 1), and uveitis anterior (n = 1). Late retinal detachment was seen in five eyes (25%) at 30 to 60 days after implantation. Followup until 1 year after implantation did not show progression of CMV retinitis in 18 to 20 patients. All received antiviral CMV therapy to protect noninfected eyes and intestinum against CMV infection. CONCLUSIONS: The ganciclovir intraocular device seemed to be effective in most cases of CMV retinitis and offers a promising alternative for cytomegalovirus retinitis. Patients pretreated longer than 6 months with i.v. ganciclovir have to be carefully selected for implantation, because resistance against ganciclovir could be three times more likely than in i.v.-therapy naive patients.

[Effect of cataracts on contrast pattern reversal stimuli exemplified by the pattern electroretinogram]. / Katarakteinfluss auf Kontrastmusterumkehrreize am Beispiel des Musterelektroretinogramms (M-ERG).

A cataract changes pattern-evoked contrast responses to a mostly unknown extent by a blurred retinal image. Pattern electroretinograms (P-ERG), evoked by a reversing checkerboard pattern, were measured (a) in 12 healthy volunteers with a cataract simulated by Bangerter foils; (b) pre- and postoperatively in 44 cataract eyes without retinal damage; and (c) in 13 healthy contralateral eyes. Slight media opacities (visual acuity 1.0 to 0.8) already diminished the amplitudes of the pattern ERG significantly, whereas the latencies did not react significantly. This can be explained by a decrease more in contrast than in luminance. Postoperatively, the amplitudes continued to increase during the first 10 weeks, when the visual acuity remained stable. The postoperative amplitudes did not reach the amplitudes of comparable healthy contralateral eyes. It is recommended that eyes be checked for cataracts before an interpretation is made.

The bronchial epithelium: a potential allogeneic target for chronic rejection after lung transplantation.

BACKGROUND: The presumptive target of the immune response in chronic pulmonary allograft rejection is the bronchial epithelium. METHODS: To further characterize human bronchial epithelial cells with regard to their ability to function as immunologic targets, cell surface antigen expression, lymphocyte proliferation, and messenger ribonucleic acid coding for a panel of mesenchymal growth factors were determined in the BET-1A human bronchial epithelial cell line. RESULTS: Interferon-gamma up-regulated cell surface intercellular adhesion molecule 1 and major histocompatibility class I and class II antigen expression by flow cytometry. Of note, tumor necrosis factor-alpha had no effect on these cell surface antigens. With the use of purified T cells from buffy coats obtained from normal volunteers, both resting and, to a greater extent, interferon-gamma-pretreated BET-1A cells stimulated lymphocyte proliferation. Finally, resting BET-1A cells expressed messenger ribonucleic acid coding for a number of mesenchymal growth factors known to stimulate smooth muscle cell migration and proliferation, the hallmark of the obliterative bronchial lesion. CONCLUSIONS: Bronchial epithelium is capable of eliciting an allogeneic immune response and expresses a number of growth factors that could potentially play a role in the development of obliterative bronchiolitis.

Cardiac allograft vasculopathy. Preferential regulation of endothelial cell-derived mesenchymal growth factors in response to a donor-specific cell-mediated allogeneic response.

We have previously reported that cell-mediated immunity to vascular endothelium is associated with the development of cardiac allograft vasculopathy (CAV). The mechanism by which a cell-mediated immune response to the coronary vascular is translated into the development of CAV is, however unknown. Peripheral blood mononuclear cells (PBMCs) obtained serially following cardiac transplantation were cocultured with donor-specific human aortic endothelial cells (HAECs) in 47 allograft recipients, 9 of whom had CAV (CAV+) at 1 year by angiography. At 20 hr following coculture, HAEC poly (A+) RNA was isolated, reverse-transcribed, and the cDNA-amplified (PCR) for a panel of growth factors (GFs) known to alter smooth muscle cell proliferation or migration. Relative quantitation of PCR product was performed using high-pressure liquid chromatography (HPLC). Three patterns of GF regulation were observed depending on the GF, the time posttransplant, and whether the patient had CAV: (1) no regulation (TGF-beta, PDGF-A early post-tx); (2) upregulation irrespective of CAV (bFGF, PDGF-B, TGF-alpha early post-tx); and (3) preferential or exclusive upregulation by CAV+ patients (PDGF-A and TGF-alpha late post-tx, HB-EGF early and late post-tx). For example, using PBMCs as stimulators, obtained 6 months posttransplant from CAV+ patients, increases in HAEC-derived PDGF-A chain (31 +/- 7 to 69 +/- 11), TGF-alpha (97 +/- 27 to 201 +/- 23), and HB-EGF (78 +/- 16 to 173 +/- 27) mRNA were demonstrated (all P<0.05 or greater using HPLC peak area as units). These data demonstrate that cell-mediated activation of vascular endothelial cells in patients with CAV results in preferential upregulation of certain endothelial-derived mesenchymal growth factors capable of stimulating smooth muscle cell proliferation and migration.

Temporal reduction in acute rejection after heart transplantation is not associated with a reduction in cell-mediated responses to donor-specific vascular endothelium.

BACKGROUND: Over the first 6 months after clinical transplantation, the incidence of rejection falls despite typically substantial decreases in maintenance immunosuppression. Despite this, chronic vascular rejection, manifested by an accelerated form of coronary artery disease is usually evident by the first annual angiogram and continues to progress over subsequent years. METHODS: To investigate this phenomenon further, peripheral blood mononuclear cells were prepared from blood samples obtained from 42 cardiac allograft recipients at 1 week, 3 months, and 6 months after transplantation and co-cultured with endothelial cells isolated and cultured from the aortas of their specific cardiac allograft donors. Donor-specific alloreactivity was assessed by (1) peripheral blood mononuclear cell proliferation (3H-thymidine incorporation) and (2) up-regulation of endothelial cell major histocompatibility complex class I and class II antigens and ICAM-1 expression (flow cytometry) at all three time points. RESULTS: Over this 6-month period, rejection incidence fell from 0.68 rejections/patient to 0.12 rejection/patient. Cyclosporine dose was reduced from 5.6 +/- 0.3 mg/kg (mean +/- standard error of the mean) to 4.5 +/- 0.2 mg/kg, prednisone dose was reduced from 0.58 +/- 0.08 mg/kg to 0.17 +/- 0.02 mg/kg, and azathioprine remained constant at approximately 2 mg/kg over the 6-month period. Despite this reduction in rejection and immunosuppression, no measure of in vitro donor-specific cell-mediated response to endothelial cells decreased over the 6-month time period. Peripheral blood mononuclear cell proliferation in response to donor-specific endothelial cells was unchanged between 1 week (916 +/- 139 counts/min [cpm]) and 3 months (896 +/- 135 cpm) and increased at 6 months (1738 +/- 243 cpm, p < 0.01). The increase in endothelial cell major histocompatibility complex class II expression in response to recipient peripheral blood mononuclear cells likewise was unchanged between 1 week (42.5 +/- 7.8 mean channel shift [mcs]) and 3 months (34.7 +/- 6.6 mcs) and increased substantially at 6 months (95.4 +/- 17.2 mcs, p < 0.02). The magnitude of the increase in endothelial cell major histocompatibility complex class I antigen and ICAM-1 expression in response to co-culture with recipient peripheral blood mononuclear cells did not change over the 6-month period. CONCLUSIONS: These data suggest an important dichotomy between cell-mediated responses to allograft parenchyma versus those to allograft vasculature and may provide an explanation for progressive vascular disease despite the absence of acute rejection.

Cardiac allograft vasculopathy. Association with cell-mediated but not humoral alloimmunity to donor-specific vascular endothelium.

BACKGROUND: Cardiac allograft vasculopathy (CAV) is an accelerated form of coronary artery disease responsible for the majority of late deaths after cardiac transplantation. Although most consider this complication a manifestation of chronic allograft rejection, it has not been established whether this disease is a consequence of humoral or cell-mediated alloreactivity. METHODS AND RESULTS: Human aortic endothelial cells (HAECs) were isolated from donor aortas obtained at the time of organ acquisition for 52 cardiac allograft recipients. Serum and peripheral blood mononuclear cells were obtained from these 52 allograft recipients at several time points during the first year after transplantation. Lymphocyte proliferation (LP) in response to donor-specific HAECs and alloantibody binding to interferon-gamma-treated donor-specific HAECs were performed and correlated with clinical parameters, including HLA matching, acute cellular rejection, and coronary artery disease on surveillance angiography. Ten of the 52 patients studied had angiographic or autopsy evidence of coronary artery disease in the first posttransplantation year (CAV+ group). The CAV+ group had higher LP responses to their donor HAECs at 1 week, 3 months, and 6 months after transplantation compared with the CAV- group (1 week: 1439 +/- 222 versus 824 +/- 141 counts per minute [cpm], P = .026; 3 months: 1282 +/- 388 versus 884 +/- 94 cpm, P = .07; 6 months: 2504 +/- 635 versus 1540 +/- 209 cpm, P = .036; CAV+ versus CAV-, respectively). Only 8 of the 52 patients had donor-specific alloantibodies, and there was no relation between antibody presence and CAV. Other clinical parameters that correlated with CAV included the level of HLA-DR mismatch and the presence of late acute rejection. CONCLUSIONS: CAV is associated with donor-specific cell-mediated alloreactivity to vascular endothelium. Humoral immunity does not appear to have a major role in this disease.

Phenotypic variations in resting and activated levels of ICAM-1 expression by cultured human aortic endothelial cells.

ICAM-1 is an inducible glycoprotein important in the adhesion, activation, and transmigration of circulating leukocytes across the vascular endothelial monolayer, and it likely plays a key role in the allogeneic response. To determine the reproducibility and significance of variations in resting levels of cell surface ICAM-1, 3 individual measurements of ICAM-1 levels were performed on 26 individual isolates of human aortic endothelial cells (HAECs) both at rest and following activation by allogeneic lymphocytes, using flow cytometry. Resting HAEC ICAM-1 levels varied 10-fold (range 6-60 mean fluorescence channels) depending on the isolate studied. There were strong correlations (r = 0.71 to 0.77, P < 0.0001) between the three measurements (performed no closer than weekly intervals on separate cultures), attesting to the consistency of the phenotypic expression. Constitutive expression of ICAM-1 was not affected by cell age, based upon comparing a subset of these isolates across 3 population doublings. Levels of HAEC ICAM-1 following allogeneic lymphocyte activation varied 15-fold (range 20-300 mean fluorescent channels) and, more important, correlated with resting ICAM-1 levels (r = 0.58, P = 0.002). Finally, constitutive ICAM-1 expression was related to TNF-alpha-induced ICAM-1 levels based upon a subset of the isolates studied. These data suggest that phenotypic, and likely genetic, differences in quiescent endothelial cell adhesion molecule expression can influence inflammatory responses including alloresponsiveness to the vasculature.