Antigen-specific T lymphocyte proliferation decreases over time in advanced chronic hepatitis C.

To evaluate T cell immunity in advanced liver disease, antigen-specific lymphoproliferative (LP) responses were prospectively studied in the context of the Hepatitis C Antiviral Long-term Treatment against Cirrhosis trial. Peripheral blood responses to hepatitis C virus (HCV), tetanus and Candida protein antigens were measured at baseline, month 12 (M12), M24, M36 and M48 in 186 patients randomized to either low-dose peginterferon-alfa-2a (PEG-IFN) only or observation. Liver histology was evaluated at baseline, M24 and M48. Patients with cirrhosis (Ishak 5-6) were less likely to have positive LP responses to HCV at baseline than patients with fibrosis (15%vs 29%, P = 0.03) and had lower levels of HCV c100 responses at baseline, M24 and M48 (P = 0.11, P = 0.05, P = 0.02, respectively). For 97 patients with complete longitudinal data, the frequency of positive LP responses to HCV, tetanus and Candida antigens declined over time (P < 0.003), and the slope of this decline was greater in the PEG-IFN treatment group than the observation group (P < 0.02). Lower levels of tetanus LP responses were associated with fibrosis progression and clinical outcomes (P = 0.009). Poorer CD4+ T cell proliferative function was associated with more advanced liver disease in chronic hepatitis C and may be further affected by long-term PEG-IFN treatment.

The Challenge study: theory-based interventions for smoking and weight loss.

Both smokers and overweight persons report frequent efforts to change their behavior. Long-term success, however, is achieved by few. Interventions are needed to improve long-term success in smoking cessation and weight loss. Our research program is designed to address this need and to test a novel conceptualization of health behavior change that is based on the premise that the initiation and the maintenance of behavior change involve different decision processes. Positive expectations about the consequences of behavior change are thought to guide decisions to initiate behavior change, whereas satisfaction with the outcomes afforded by one's behavior guides decisions about maintenance. In the first phase of our research program, we are evaluating the effect people's expectations about the benefits of behavior change have on immediate and long-term behavioral outcomes. Specifically, participants are assigned to either an 'optimistic' treatment condition that emphasizes positive expectations for outcomes or a 'balanced' treatment condition that gives equal weight to the benefits and costs associated with behavior change. The impact of manipulating people's expectations about behavior change will be examined in the areas of smoking cessation and weight loss. Results of these studies will advance research on health behavior change by informing practical and theoretical understanding of the factors that control decisions to initiate a new pattern of behavior and to maintain it.

Ambiguity and mistakes in the pediatric cardiology vernacular.

The pediatric cardiology vernacular is replete with ambiguous and erroneous terminology. This article discusses several examples in a plea to bring the accuracy and precision of the scientific method to the clinical pediatric cardiology vernacular.

Induction of T lymphocyte responses to dengue virus by a candidate tetravalent live attenuated dengue virus vaccine.

Development of a safe and immunogenic tetravalent dengue virus (DV) vaccine has been designated as a priority by the World Health Organization. We characterized the T cell response to DV induced by a candidate live attenuated tetravalent DV vaccine as part of a phase I study. Proliferation and cytotoxic T lymphocyte (CTL) responses to multiple DV serotypes were detected in six of six and four of four subjects studied, respectively. Proliferation responses were higher to DV serotypes 1 and 3 than to serotypes 2 and 4. CTL responses were higher to DV serotypes 2 and 3 than to serotype 1, and included serotype cross-reactive responses. Production of interferon-gamma, but not IL-4, was observed in response to DV stimulation. This candidate vaccine is immunogenic for both CD4+ and CD8+ T lymphocytes. However, T cell responses to the four DV serotypes were not equivalent, suggesting that the vaccine could be further optimized.

c-Jun decreases voltage-gated K(+) channel activity in pulmonary artery smooth muscle cells.

BACKGROUND: Activity of voltage-gated K(+) (K(v)) channels controls membrane potential (E(m)) that regulates cytosolic free Ca(2+) concentration ([Ca(2+)](cyt)) by regulating voltage-dependent Ca(2+) channel function. A rise in [Ca(2+)](cyt) in pulmonary artery smooth muscle cells (PASMCs) triggers vasoconstriction and stimulates PASMC proliferation. Whether c-Jun, a transcription factor that stimulates cell proliferation, affects K(v) channel activity in PASMCs was investigated. METHODS AND RESULTS: Infection of primary cultured PASMCs with an adenoviral vector expressing c-jun increased the protein level of c-Jun and reduced K(v) currents (I(K(V))) compared with control cells (infected with an empty adenovirus). Using single-cell reverse transcription-polymerase chain reaction, we observed that the mRNA level of Kv1.5 and the current density of I(K(V)) were both attenuated in c-jun-infected PASMCs compared with control cells and cells infected with antisense c-jun. Overexpression of c-Jun also upregulated protein expression of Kvbeta(2) and accelerated I(K(V)) inactivation. Furthermore, E(m) was more depolarized and [(3)H]thymidine incorporation was greater in PASMCs infected with c-jun than in control cells and cells infected with antisense c-jun. CONCLUSIONS: These results suggest that c-Jun-mediated PASMC proliferation is associated with a decrease in I(K(V)). The resultant membrane depolarization increases [Ca(2+)](cyt) and enhances PASMC growth.

The effects of message framing and ethnic targeting on mammography use among low-income women.

The authors examined the effects that differently framed and targeted health messages have on persuading low-income women to obtain screening mammograms. The authors recruited 752 women over 40 years of age from community health clinics and public housing developments and assigned the women randomly to view videos that were either gain or loss framed and either targeted specifically to their ethnic groups or multicultural. Loss-framed, multicultural messages were most persuasive. The advantage of loss-framed, multicultural messages was especially apparent for Anglo women and Latinas but not for African American women. These effects were stronger after 6 months than after 12 months.

Staying up-to-date through distance education: the radiation therapy perspective.

BACKGROUND: Distance education (DE) courses are offered to medical radiation technologists (therapy) [MRT(T)] in Canada for professional development (PD). METHODS: A survey of 300 therapists was conducted to identify potential participants and factors that can influence DE participation and learning. RESULTS: The motivation to take PD is intrinsic, for personal growth and fulfillment, rather than to satisfy employment or provincial requirements. There is interest in DE because of its accessibility. Work constraints appear to be more restrictive than domestic ones and little support for PD is perceived from the cancer centers. CONCLUSIONS: These findings raise implications for professional development in cancer centers that are broader than the original objective of optimizing course design.

Pediatric cutaneous malignant fibrous histiocytoma.

Malignant fibrous histiocytoma (MFH) is an aggressive soft-tissue sarcoma that most commonly occurs in the skeletal muscle of the extremities or retroperitoneum of adults. Although the majority of MFH is located beneath the fascia, the tumor occasionally occurs in the subcutaneous tissue. MFH rarely occurs in children and the disease course, prognosis, and outcome in younger patients has not been well described. We report a case of cutaneous MFH presenting on the thigh of a 12-year-old boy.

Atrial septostomy as a bridge to lung transplantation in patients with severe pulmonary hypertension.

Long waiting times for lung transplantation have limited the survival of patients with advanced pulmonary hypertension. Atrial septostomy has been used in this group of patients in an attempt to prolong survival. We evaluated the results of atrial septostomy in 12 patients using the static graded balloon dilation technique. Between December 1990 and May 1998, 10 women and 2 men (ages 13 to 56 years, mean 37 years) underwent atrial septostomy. Nine patients had primary and 3 patents had secondary pulmonary hypertension. Five patients deteriorated despite long-term intravenous prostacyclin infusions. The atrial septum was crossed with a Brockenbrough needle, followed by an 0.035-J exchange wire and progressively larger catheter balloons for atrial septal dilation, until systemic oxygen saturation decreased 5% to 10%. An atrial septal defect was successfully created in each patient. The mean right atrial pressure decreased from 23 to 18 mm Hg and the mean systemic oxygen saturation decreased from 93% to 85%. The mean cardiac index increased from 1.7 to 2.1 L/min/m2 and the mean systemic oxygen transport increased from 268 to 317 ml/min/m2. Complications occurred in 3 patients: transient hypotension during transesophageal echocardiography, a femoral pseudoaneurysm, and a femoral arteriovenous fistula. After septostomy, 6 patients had clinical improvement (resolution of ascites, edema, and no further episodes of syncope); 5 of these 6 patients underwent lung transplantation a mean of 6.1 months after septostomy. Six patients did not have clinical improvement after septostomy. Atrial septostomy improves the hemodynamic status and may be useful as a bridge to lung transplantation in selected patients with pulmonary hypertension.

Partial agonist effect influences the CTL response to a heterologous dengue virus serotype.

Activation of dengue serotype-cross-reactive memory CTL during secondary dengue virus (DV) infection is thought to be important in the pathogenesis of dengue hemorrhagic fever. To model this effect, we studied the CTL responses to DV types 2 (D2V) and 3 (D3V) in PBMC from an individual previously infected with D3V. DV-specific CD8+ CTL from this donor recognized two HLA-B62-restricted epitopes on the NS3 protein, aa 71-79 (SVKKDLISY) and 235-243 (AMKGLPIRY). Both D3V-specific and D2V/D3V-cross-reactive CTL clones were detected for each epitope; all D2V-reactive CTL clones could lyse D2V-infected autologous cells. CTL responses to both epitopes were detected in bulk cultures stimulated with D3V, but PBMC stimulated with D2V recognized only the 235-243 epitope. IFN-gamma enzyme-linked immunospot assay showed that the D2V (71-79) peptide (DVKKDLISY) did not efficiently activate T cells. Analysis of a CTL clone suggests that the D2V (71-79) peptide acts as a partial agonist, able to sensitize target cells for lysis and inducing only minimal proliferation at high concentrations. These results suggest that variant peptide sequences present in the heterologous DV serotype can influence the CTL response in vivo during secondary DV infection.

Message framing and sunscreen use: gain-framed messages motivate beach-goers.

Prospect theory suggests that people respond differentially to factually equivalent messages depending on how these messages are framed (A. Tversky & D. Kahneman, 1981). A. J. Rothman and P. Salovey (1997) relied on prospect theory to predict that messages highlighting potential "gains" should promote prevention behaviors such as sunscreen use best. This experiment compared the effectiveness of 4 differently framed messages (2 highlighting gains, 2 highlighting losses) to persuade 217 beach-goers to obtain and use sunscreen. Attitudes and intentions were measured before and immediately following the delivery of the framed information, and after completing the questionnaire participants were given a coupon redeemable for a small bottle of sunscreen later that same day. People who read either of the 2 gain-framed brochures, compared with those who read either of the 2 loss-framed brochures, were significantly more likely to (a) request sunscreen, (b) intend to repeatedly apply sunscreen while at the beach, and (c) intend to use sunscreen with a sun protection factor of 15 or higher.

Bystander target cell lysis and cytokine production by dengue virus-specific human CD4(+) cytotoxic T-lymphocyte clones.

Dengue hemorrhagic fever, the severe form of dengue virus infection, is believed to be an immunopathological response to a secondary infection with a heterologous serotype of dengue virus. Dengue virus capsid protein-specific CD4(+) cytotoxic T-lymphocyte (CTL) clones were shown to be capable of mediating bystander lysis of non-antigen-presenting target cells. After activation by anti-CD3 or in the presence of unlabeled antigen-presenting target cells, these clones could lyse both Jurkat cells and HepG2 cells as bystander targets. Lysis of HepG2 cells suggests a potential role for CD4(+) CTL in the liver involvement observed during dengue virus infection. Three CD4(+) CTL clones were demonstrated to lyse cognate, antigen-presenting target cells by a mechanism that primarily involves perforin, while bystander lysis occurred through Fas/Fas ligand interactions. In contrast, one clone used a Fas/Fas ligand mechanism to lyse both cognate and bystander targets. Cytokine production by the CTL clones was also examined. In response to stimulation with D2 antigen, CD4(+) T-cell clones produced gamma interferon, tumor necrosis factor alpha (TNF-alpha) and TNF-beta. The data suggest that CD4(+) CTL clones may contribute to the immunopathology observed upon secondary dengue virus infections through direct cytolysis and/or cytokine production.

Early immune activation in acute dengue illness is related to development of plasma leakage and disease severity.

T lymphocyte activation and increased cytokine levels have been described in retrospective studies of children presenting with dengue hemorrhagic fever (DHF). Serial plasma samples obtained in a prospective study of Thai children presenting with <72 h of fever were studied. Plasma levels of 80-kDa soluble tumor necrosis factor receptors (sTNFRs) were higher in children who developed DHF than in those with dengue fever (DF) or other nondengue febrile illnesses (OFIs) and were correlated with the degree of subsequent plasma leakage. Soluble CD8 and soluble interleukin-2 receptor levels were also elevated in children with DHF compared with those with DF. Interferon-gamma and sTNFR 60-kDa levels were higher in children with dengue than in those with OFIs. TNF-alpha was detectable more often in DHF than in DF or OFIs (P<.05). These results support the hypothesis that immune activation contributes to the pathogenesis of DHF. Further studies evaluating the predictive value of sTNFR80 for DHF are warranted.

High levels of cytokine-producing cells in the lung tissues of patients with fatal hantavirus pulmonary syndrome.

Hantavirus pulmonary syndrome (HPS) is characterized by the rapid onset of pulmonary edema and a high case-fatality rate. Hantavirus antigens have been demonstrated in pulmonary capillary endothelial cells, but the mechanisms causing capillary leakage remain unclear. Immunohistochemical staining was used to enumerate cytokine-producing cells (monokines: interleukin [IL]-1alpha, IL-1beta, IL-6, and tumor necrosis factor [TNF]-alpha; lymphokines: interferon-gamma, IL-2, IL-4, and TNF-beta) in tissues obtained at autopsy from subjects with HPS. High numbers of cytokine-producing cells were seen in the lung and spleen tissues of HPS patients, but only low numbers in the livers and kidneys. A modest increase in the numbers of cytokine-producing cells was detected in the lungs of patients who died with non-HPS acute respiratory distress syndrome (ARDS), and very few (or no) cytokine-producing cells were detected in the lungs of patients who died of causes other than ARDS. These results suggest that local cytokine production may play an important role in the pathogenesis of HPS.

Treating people with information: an analysis and review of approaches to communicating health risk information.

The communication of risk information is a fundamental aspect of nearly all health promotion interventions. However, no consensus exists regarding the most effective way to provide people with risk information. We will review and evaluate the relative merits of two approaches to risk communication. One approach relies on the presentation of numerical information regarding the probability of a health problem occurring, whereas the other relies on the presentation of information about the antecedents and consequences of a health problem. Because people have considerable difficulty understanding and using quantitative information, the effectiveness of interventions that rely solely on numerical probability information has been limited. Interventions that provide people with a broader informational context in which to think about a health problem have had greater success systematically influencing perceptions of personal risk but have several important limitations. However, before any final conclusions can be drawn regarding the relative merits of different communication strategies, investigators must agree on the specific criteria that should be used to identify an effective intervention.

Assessment of human CD4+ and CD8+ T lymphocyte responses in experimental viral vaccine studies.

The traditional in vitro correlate of immunological protection is the induction by a vaccine of neutralizing antibodies against the virus. It was formerly assumed that protection induced by a vaccine was solely due to neutralizing antibodies. Neutralizing antibodies are potent in the prevention of certain diseases, but virus-specific CD4+ T helper cells aid in the proliferation of specific antigen-triggered B cells to make antibodies. CD8+ T cells are responsible for eliminating virus-infected cells during viral illness, and may act as a second line of defence by becoming activated and eliminating any cells that become infected despite the presence of neutralizing antibodies, for example because of a large challenge dose or antigenic variation at the antibody combining sites. We will briefly review our approaches for measuring human virus-specific CD4+ and CD8+ T cell responses to experimental vaccines. It is critically important to have sensitive, quality controlled assays, including positive controls. There are many potential variables in human T cell assays and pitfalls, which usually result in negative CTL results. Uninterpretable data are to be expected unless adequate preliminary testing has been done to establish sensitive, specific and controlled human antigen specific CD4+ and CD8+ T cell assays.

Antisense fosB RNA inhibits thrombin-induced hypertrophy in cultured pulmonary arterial smooth muscle cells.

BACKGROUND: We have previously reported that fosB mRNA is induced by hypertrophic stimuli (thrombin, angiotensin II) but not proliferative stimuli (platelet-derived growth factor, basic fibroblast growth factor) in pulmonary arterial smooth muscle cells (PASMCs) (J Biol Chem. 1994;9:6399-6404). Our aim in the present study was to investigate the potential role of FosB in PASMC hypertrophy. METHODS AND RESULTS: Adenoviruses carrying sense or antisense fosB RNA expression cassettes were used to infect cultured PASMCs with the aim of increasing or inhibiting fosB expression, respectively. We examined whether fosB expression modification affected the growth of quiescent PASMCs, thrombin-induced hypertrophy, or platelet-derived growth factor-induced proliferation. PASMC growth was assessed by daily cell number count, determination of [3H]leucine incorporation, and quantification of total cellular protein. Neither an increase nor a decrease in FosB protein expression caused a significant change in the growth of quiescent PASMCs over a period of 96 hours, indicating that FosB alone is not sufficient to induce hypertrophy. Modification of FosB levels did not affect platelet-derived growth factor-induced PASMC proliferation. An increase in FosB expression did not augment thrombin-induced hypertrophy; however, inhibition of FosB expression resulted in a diminution of thrombin-induced hypertrophy by 58+/-6% (P<0.005). CONCLUSIONS: These results suggest that FosB is necessary but not sufficient for thrombin-induced hypertrophy in cultured PASMCs.

Percutaneous pulmonary endoarterial biopsy in an experimental model of pulmonary hypertension.

STUDY OBJECTIVES: The aims of this study were: to evaluate the performance of a novel arterial biopsy catheter in obtaining pulmonary endovascular samples in hypertensive dogs; to compare the results of pulmonary endoarterial biopsy in hypertensive vs normotensive dogs; and to assess the histologic changes in the hypertensive model. DESIGN AND INTERVENTIONS: Thirty-four dogs (27 with normal pulmonary arterial pressures and seven with pulmonary hypertension) were catheterized through an external jugular vein to obtain endovascular biopsy samples from distal pulmonary arteries 2 to 3 mm in luminal diameter. To induce pulmonary hypertension, seven dogs were given repeated infusions of 0.6- to 0.9-mm ceramic microspheres into the superior vena cava. Endoarterial samples were obtained at pulmonary systolic arterial pressures ranging from 10 to 110 mm Hg. MEASUREMENTS AND RESULTS: Sixty-two biopsy catheterization procedures were performed in the 34 dogs. After 12 initial procedures of technique refinement, endoarterial samples were obtained in each of the last 50 procedures (21 in normotensive dogs and 29 in hypertensive dogs). The average number of endovascular biopsy samples retrieved was 7.1 (range, 2 to 12) from a mean of 8.6 (range, 2 to 15) biopsy attempts per catheterization (success rate=83%). The average biopsy piece measured 1.13 mm in length, 0.33 mm in depth, and up to 1.0 mm in width. The biopsy success rates and endoarterial sample sizes were similar in normotensive and hypertensive dogs. Smooth muscle cells and endothelial cells were grown from the biopsy samples. There were no significant procedural complications, except for one self-limited hemorrhage. Histologically, samples obtained from dogs with pulmonary hypertension showed characteristic changes when compared with biopsies from normotensive dogs. CONCLUSION: This new endoarterial biopsy catheter was safe and effective when used to obtain pulmonary endoarterial samples in dogs with normal and experimentally elevated pulmonary arterial pressures. The quality and quantity of the biopsy samples allowed identification of pathologic changes.

Percutaneous coil occlusion of ascending aorta to pulmonary artery shunts.

Two patients with pulmonary atresia and intact ventricular septum each underwent early palliative surgery with a pulmonary valvotomy and an ascending aorta to pulmonary artery shunt. Adequate right ventricular growth and relief of pulmonary stenosis rendered the shunts unnecessary. The shunts were successfully occluded percutaneously with Gianturco coils.

Identification of mutations in the human PATCHED gene in sporadic basal cell carcinomas and in patients with the basal cell nevus syndrome.

Mutations in PATCHED (PTC), the human homolog of the Drosophila patched gene, have been identified in most exons of the gene in patients with the basal cell nevus syndrome and in sporadic basal cell carcinomas. We have screened the 23 PTC exons for mutations using single strand conformation polymorphism analysis of DNA from 86 basal cell nevus syndrome probands, 26 sporadic basal cell carcinomas, and seven basal cell nevus syndrome-associated basal cell carcinomas. This screen identified mutations located in eight exons in 13 of the basal cell nevus syndrome patients and in three of the tumors. The most common mutations were frameshifts resulting in premature chain termination. These results provide further evidence for the crucial role of PTC as a tumor suppressor in human keratinocytes.