Mediating a host cell signaling pathway linked to overwinter mortality offers a promising therapeutic approach for improving bee health

INTRODUCTION

Honey bees provides valuable pollination services for world food crops and wild flowering plants which are habitats of many animal species and remove carbon dioxide from the atmosphere, a powerful tool in the fight against climate change. Nevertheless, the honey bee population has been declining and the majority of colony losses occur during the winter.

OBJECTIVES

The goal of this study was to understand the mechanisms underlying overwinter colony losses and develop novel therapeutic strategies for improving bee health.

METHODS

First, pathogen prevalence in overwintering bees were screened between 2015 and 2018. Second, RNA sequencing (RNA-Seq) for transcriptional profiling of overwintering honey bees was conducted and qRT-PCR was performed to confirm the results of the differential expression of selected genes. Lastly, laboratory bioassays were conducted to measure the effects of cold challenges on bee survivorship and stress responses and to assess the effect of a novel medication for alleviating cold stress in honey bees.

RESULTS

We identified that sirtuin signaling pathway is the most significantly enriched pathway among the down-regulated differentially expressed genes (DEGs) in overwintering diseased bees. Moreover, we showed that the expression of SIRT1 gene, a major sirtuin that regulates energy and immune metabolism, was significantly downregulated in bees merely exposed to cold challenges, linking cold stress with altered gene expression of SIRT1. Furthermore, we demonstrated that activation of SIRT1 gene expression by SRT1720, an activator of SIRT1 expression, could improve the physiology and extend the lifespan of cold-stressed bees.

CONCLUSION

Our study suggests that increased energy consumption of overwintering bees for maintaining hive temperature reduces the allocation of energy toward immune functions, thus making the overwintering bees more susceptible to disease infections and leading to high winter colony losses. The novel information gained from this study provides a promising avenue for the development of therapeutic strategies for mitigating colony losses, both overwinter and annually.

[The clinical value of multi-target stool fecal immunochemical test-DNA in early screening and diagnosis for colorectal cancer]

Objective: To investigate the clinical diagnostic value of multi-target stool fecal immunochemical test-DNA (FIT-DNA) test in colorectal cancer (CRC) and advanced adenoma (AA). Methods: A total of 235 patients who were undergoing colonoscopy or colorectal cancer surgery in the Cancer Hospital, Chinese Academy of Medical Sciences from April 2021 to January 2022 were prospectively enrolled. There were 141 males and 94 females, with an average age of (55±13) years (22-86). The patients were divided into two groups, including 215 patients who were first diagnosed but not treated (86 cases of CRC, 12 cases of AA, 25 cases of non-advanced adenoma, 8 cases of hyperplastic or other polyps and 84 apparently healthy cases) and 20 patients in the intervention group (2 cases with a history of CRC surgery, 6 cases with a history of endoscopic surgery, 4 non-CRC patients with special diseases and 8 cases with a history of neoadjuvant chemoradiotherapy). Fresh stool samples were collected before intestinal preparation or surgery for FIT-DNA test using the matching kit for sample processing and nucleic acid purification. KRAS mutation and methylation of BMP3 and NDRG4 genes were detected by fluorescence probe method, and FIT method was employed to detect fecal occult blood. Colonoscopy or pathological biopsy results were used as the gold standard. And the screening and diagnostic efficacy of FIT-DNA test for colorectal cancer and advanced adenoma were evaluated by receiver operating curve (ROC). Results: The sensitivity of FIT-DNA test for early colorectal cancer and advanced adenoma was 7/7 and 8/12, respectively. And the negative predictive value was 98.1% (104/106) and 93.7% (104/111), respectively. The overall screening sensitivity for both early colorectal cancer and advanced adenoma was 15/19, and the negative predictive value was 96.3% (104/108). Besides, the area under the curves (AUCs) were 0.982 (95%CI: 0.960-1.000, P<0.05), 0.758 (95%CI: 0.592-0.924, P<0.05) and 0.841 (95%CI: 0.724-0.957, P<0.05), respectively. Moreover, the diagnostic sensitivity of FIT-DNA test was 98.8% (85/86) for colorectal cancer, 8/12 for advanced adenoma, and 94.9% (93/98) for both colorectal cancer and advanced adenoma, with a specificity of 88.9% (104/117). The AUCs were 0.968 (95%CI: 0.937-0.997, P<0.05), 0.758 (95%CI: 0.592-0.924, P<0.05) and 0.942 (95%CI: 0.905-0.979, P<0.05), respectively. After the inclusion of intervention group, the overall diagnostic sensitivity and specificity of FIT-DNA test was 91.6% (98/107) and 89.1% (114/128), respectively. Conclusion: FIT-DNA test has a high early screening and diagnostic efficacy for colorectal cancer.

RNA Interference-Mediated Knockdown of Genes Encoding Spore Wall Proteins Confers Protection against Nosema ceranae Infection in the European Honey Bee, Apis mellifera

Nosema ceranae (Opisthosporidia: Microsporidia) is an emergent intracellular parasite of the European honey bee (Apis mellifera) and causes serious Nosema disease which has been associated with worldwide honey bee colony losses. The only registered treatment for Nosema disease is fumagillin-b, and this has raised concerns about resistance and off-target effects. Fumagillin-B is banned from use in honey bee colonies in many countries, particularly in Europe. As a result, there is an urgent need for new and effective therapeutic options to treat Nosema disease in honey bees. An RNA interference (RNAi)-based approach can be a potent strategy for controlling diseases in honey bees. We explored the therapeutic potential of silencing the sequences of two N. ceranae encoded spore wall protein (SWP) genes by means of the RNAi-based methodology. Our study revealed that the oral ingestion of dsRNAs corresponding to SWP8 and SWP12 used separately or in combination could lead to a significant reduction in spore load, improve immunity, and extend the lifespan of N. ceranae-infected bees. The results from the work completed here enhance our understanding of honey bee host responses to microsporidia infection and highlight that RNAi-based therapeutics are a promising treatment for honey bee diseases.

[Clinical application value of combined detection of serum miR-378 and miR-21 in gastric cancer]

Objective: To investigate the clinical value of combined detection of serum miR-378 and miR-21 in gastric cancer (GC). Methods: Eighty-seven patients with GC and 78 patients with colorectal cancer(CRC) from National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences were selected, 83 individuals undergoing healthy physical examination were selected as the healthy controls. The levels of serum miR-378 and miR-21 were detected by quantitative real-time PCR (RT-qPCR) (result data were transformed as log2 for analysis). Results: Relative expression levels of miR-378 in the serum were -1.24, -3.25 and -2.73 in healthy controls, GC and CRC patients, respectively. Compared with the healthy controls, the levels of serum miR-378 were significantly decreased in GC and CRC patients (both P<0.05). Relative expression levels of miR-21 in the serum were 0.11, 2.34 and 2.47 in healthy controls, GC and CRC patients, respectively. Compared with the healthy controls, the levels of serum miR-21 were significantly up-regulated in GC and CRC patients (both P<0.05). Moreover, the serum level of miR-378 in GC patients was inversely associated with tumor clinical stage (P<0.05). However, the level of miR-21 showed no significant differences among patients with different clinical and pathological characteristics (all P>0.05). The area under the receiver operating characteristic curve (AUC), sensitivity and specificity of miRNA-378 to diagnose GC was 0.770, 82.0% and 66.0%, respectively, and were 0.900, 85.0%, and 88.0% of miR-21, respectively. The AUC, sensitivity and specificity of combined detection of serum miR-378 and miR-21 to diagnose GC were 0.930, 92.0% and 87.0%, respectively, while the AUC of combined detection of serum CEA and CA-199 was 0.767, the AUC of combined all of the four factors was 0.946. Conclusion: The combined detection of serum miR-378 and miR-21 have a certain effect on diagnosis of GC.

New evidence showing that the destruction of gut bacteria by antibiotic treatment could increase the honey bee's vulnerability to Nosema infection

It has become increasingly clear that gut bacteria play vital roles in the development, nutrition, immunity, and overall fitness of their eukaryotic hosts. We conducted the present study to investigate the effects of gut microbiota disruption on the honey bee's immune responses to infection by the microsporidian parasite Nosema ceranae. Newly emerged adult workers were collected and divided into four groups: Group I-no treatment; Group II-inoculated with N. ceranae, Group III-antibiotic treatment, and Group IV-antibiotic treatment after inoculation with N. ceranae. Our study showed that Nosema infection did not cause obvious disruption of the gut bacterial community as there was no significant difference in the density and composition of gut bacteria between Group I and Group II. However, the elimination of gut bacteria by antibiotic (Groups III and IV) negatively impacted the functioning of the honey bees' immune system as evidenced by the expression of genes encoding antimicrobial peptides abaecin, defensin1, and hymenoptaecin that showed the following ranking: Group I > Group II > Group III > Group IV. In addition, significantly higher Nosema levels were observed in Group IV than in Group II, suggesting that eliminating gut bacteria weakened immune function and made honey bees more susceptible to Nosema infection. Based on Group IV having displayed the highest mortality rate among the four experimental groups indicates that antibiotic treatment in combination with stress, associated with Nosema infection, significantly and negatively impacts honey bee survival. The present study adds new evidence that antibiotic treatment not only leads to the complex problem of antibiotic resistance but can impact honey bee disease resistance. Further studies aimed at specific components of the gut bacterial community will provide new insights into the roles of specific bacteria and possibly new approaches to improving bee health.

Israeli acute paralysis virus: epidemiology, pathogenesis and implications for honey bee health

Israeli acute paralysis virus (IAPV) is a widespread RNA virus of honey bees that has been linked with colony losses. Here we describe the transmission, prevalence, and genetic traits of this virus, along with host transcriptional responses to infections. Further, we present RNAi-based strategies for limiting an important mechanism used by IAPV to subvert host defenses. Our study shows that IAPV is established as a persistent infection in honey bee populations, likely enabled by both horizontal and vertical transmission pathways. The phenotypic differences in pathology among different strains of IAPV found globally may be due to high levels of standing genetic variation. Microarray profiles of host responses to IAPV infection revealed that mitochondrial function is the most significantly affected biological process, suggesting that viral infection causes significant disturbance in energy-related host processes. The expression of genes involved in immune pathways in adult bees indicates that IAPV infection triggers active immune responses. The evidence that silencing an IAPV-encoded putative suppressor of RNAi reduces IAPV replication suggests a functional assignment for a particular genomic region of IAPV and closely related viruses from the Family Dicistroviridae, and indicates a novel therapeutic strategy for limiting multiple honey bee viruses simultaneously and reducing colony losses due to viral diseases. We believe that the knowledge and insights gained from this study will provide a new platform for continuing studies of the IAPV–host interactions and have positive implications for disease management that will lead to mitigation of escalating honey bee colony losses worldwide.

The mysterious outbreak of honey bee Colony Collapse Disorder (CCD) in the US in 2006–2007 has attracted massive media attention and created great concerns over the effects of various risk factors on bee health. Understanding the factors that are linked to the honey bee colony declines may provide insights for managing similar incidents in the future. We conducted this study to elucidate traits of a key honey bee virus, Israeli acute paralysis virus. We then developed an innovative strategy to control virus levels. The knowledge and insights gained from this study will have positive implications for bee disease management, helping to mitigate worldwide colony losses.

Evaluation of cage designs and feeding regimes for honey bee (Hymenoptera: Apidae) laboratory experiments

The aim of this study was to improve cage systems for maintaining adult honey bee (Apis mellifera L.) workers under in vitro laboratory conditions. To achieve this goal, we experimentally evaluated the impact of different cages, developed by scientists of the international research network COLOSS (Prevention of honey bee COlony LOSSes), on the physiology and survival of honey bees. We identified three cages that promoted good survival of honey bees. The bees from cages that exhibited greater survival had relatively lower titers of deformed wing virus, suggesting that deformed wing virus is a significant marker reflecting stress level and health status of the host. We also determined that a leak- and drip-proof feeder was an integral part of a cage system and a feeder modified from a 20-ml plastic syringe displayed the best result in providing steady food supply to bees. Finally, we also demonstrated that the addition of protein to the bees' diet could significantly increase the level ofvitellogenin gene expression and improve bees' survival. This international collaborative study represents a critical step toward improvement of cage designs and feeding regimes for honey bee laboratory experiments.

Lifetime exposure to cigarette smoking and the development of adult-onset atopic dermatitis

BACKGROUND

Adult-onset atopic dermatitis (AD) has recently been recognized as a distinct disease entity, but its risk factors have not yet been clearly defined. Although gestational and perinatal exposure to tobacco smoking may be associated with the development of classic AD, the association between active/passive smoking and adult-onset AD remains controversial.

OBJECTIVES

To determine if exposure to smoking, including environmental tobacco smoke (ETS), is associated with the risk of adult-onset AD.

METHODS

Tobacco smoking and exposure to ETS were measured in a case-control association analysis in 83 patients with physician-diagnosed adult-onset AD and 142 age- and sex-matched controls.

RESULTS

Multiple logistic regression analyses showed that, among the potential environmental risk factors, both current and ever smoking were significant risk factors for adult-onset AD [odds ratio (OR) 4·994 and 3·619, respectively], compared with never smoking. Also, packs per year was significantly associated with adult-onset AD (OR 1·058, 95% confidence interval 1·028-1·089), suggesting a lifelong cumulative risk in current smokers. Moreover, nonsmokers with adult-onset AD reported significantly more exposure to ETS.

CONCLUSIONS

Early and/or current exposure to cigarette smoking may contribute cumulatively to the development of adult-onset AD. Exposure to ETS in childhood is associated with the development of adult-onset AD. Adults should be discouraged from smoking to prevent adult-onset AD in themselves and their family members.

Antioxidant and pro-oxidant properties of chlorhexidine and its interaction with calcium hydroxide solutions

AIM

To evaluate the antioxidant and pro-oxidant properties of chlorhexidine (CHX).

METHODOLOGY

The scavenging and generation of reactive oxygen species (ROS) by CHX in the presence or absence of saturated Ca(OH)(2) solutions was evaluated. The reaction emitted chemiluminescence in the presence of lucigenin thus was determined by a luminometer to evaluate the levels of ROS production. Changes in DNA conformation were analysed by agarose gel electrophoresis. Paired Student's t-test was used to compare the difference between groups.

RESULTS

Chlorhexidine (0.00002-0.02%) effectively scavenged 56-88% of the superoxide radicals generated by the xanthine/xanthine oxidase reaction. Through analysis of PUC18 DNA conformation changes, CHX was shown to be a mild scavenger of hydroxyl radicals generated by H(2)O(2) plus FeCl(2). However, CHX (>0.083%) decreased the mobility of PUC18 plasmid DNA with potential production of DNA-DNA cross-link and severe DNA breaks (presence of DNA smear) at further higher concentrations. Furthermore, CHX induced ROS production including H(2)O(2) and superoxide radicals in 0.1N NaOH (pH = 12.76) or Ca(OH)(2) (pH = 12.5) solutions.

CONCLUSION

Chlorhexidine exhibited both antioxidant and pro-oxidant properties under different conditions. These events are possibly involved in the killing of root canal and periodontal microorganisms when CHX and Ca(OH)(2) were used in combination or separately. Potential genotoxicity and tissue damage when extruded into the periradicular tissue and at higher concentrations should be considered during periodontal and endodontic practice.

Molecular genetics of human immune responsiveness to allergens

Specific immune responsiveness to certain highly purified allergens is significantly associated with particular HLA-D types. In one striking example, IgE and IgG responsiveness to the ragweed Amb V (Ra5) allergens is strongly associated with HLA-DR2/Dw2. We studied the HLA-D gene sequences of 67 Caucasoid subjects. All Dw2+ (Dw2 +/- in one case) high responders to Amb a V, before or after high-dose ragweed immunotherapy, possessed typical DRB1*2.2 and DRB3*2.2 (Dw2-associated DR beta) gene sequences. Their DQB1 genes all had typical Dw2-associated DQB1*1.2 sequences, with two exceptions (DQB1*1.21 and DQB1*1.18, that are usually associated with Dw21 and Dw18, respectively). The finding of these unusual sequence combinations in these Amb a V responders implicates a DR alpha beta I2.2 or a DR alpha beta III2.2 molecule as the major Amb a V Ir gene product. This conclusion is supported by our finding of one non-responder (after prolonged immunotherapy) who possessed the DQ1.2, but not the DR2.2, sequences. In ragweed-allergic subjects further data suggest that a DR2.2 molecule is generally a necessary and almost always a sufficient requirement for high Amb a V responsiveness. An Amb a V-specific T cell clone obtained from a Dw2+ subject was DR-restricted according to inhibition studies using anti-HLA-D monoclonal antibodies. Also, antigen-presenting cells that were DR2.2+ or DR2.12+, but not DR2.21+ or DR2.22+, were able to present antigen to the cloned T cells, implicating certain DR2 molecules as restriction elements. In similar studies using the rye grass allergen Lol p III we obtained preliminary data implicating the DR beta I sequence E9 YSTS13 (found in DR3, DR5 and DRw6 genotypes) in the recognition of a major Lol p III agretope. Since Lol p I and II are homologous to Lol p III in one region of their amino acid sequences the EYSTS sequence may also be involved in the recognition of similar agretopes of these molecules. These and other studies demonstrate the power of the allergy model for genetic and molecular studies of the human immune response.

Sequence variants of the secreted phosphoprotein 1 gene are associated with total serum immunoglobulin E levels in a Japanese population

BACKGROUND

Secreted phosphoprotein 1 (SPP1) is a cytokine with pleiotrophic immunological activities, including activation of macrophage chemotaxis and T-helper type 1 (Th1) immune responses. SPP1 gene polymorphisms have been shown to be associated with several immune inflammatory diseases including multiple sclerosis (MS), which is characterized by fewer allergic symptoms and lower numbers of allergen sensitizations.

OBJECTIVE

The present study examined whether SPP1 gene polymorphisms are associated with total serum IgE levels, atopy and asthma in a Japanese population.

METHODS

This case-control association analysis examined 611 subjects, including 268 subjects with asthma. We genotyped three promoter and two exon polymorphisms at SPP1: -1687A/G; -381T/C; -94 deletion/G; 5891C/T; and 7052T/C. Results Association analyses of SPP1 polymorphisms showed that homozygosities for the 5891T allele (P=0.009) and 7052C allele (P=0.001) were significantly associated with increased levels of total IgE in non-asthmatic subjects. However, these variants were not associated with asthma and atopy. Interestingly, individuals carrying the 5891C allele, which is more prevalent in patients with MS in Japanese populations, displayed significantly lower levels of total serum IgE. Individuals homozygous for the 7052C allele, which is associated with development of systemic lupus erythematosus, displayed significantly higher total serum IgE levels.

CONCLUSION

These findings suggest that genetic polymorphisms in SPP1 may play a role in controlling basal levels of total serum IgE, independent of atopy.

Genetic aspects of asthma

Over the last few years, a significant progress has been made in understanding of the genetic basis of asthma. This has led to the identification of several chromosomal regions and loci showing linkage to and association with asthma and asthma-linked phenotypes. Recent positional cloning approaches have also been informative in identifying several strong candidate genes for asthma. The next challenge will involve validation of these findings and, importantly, identification of the functional basis in the pathophysiology of asthma. This review will describe the power of positional cloning for the identification of asthma genes, highlight the functional importance of the genetic variants, and address the gene-gene and gene-environment interactions that are pertinent to this challenging field.

Modulation of bronchial epithelial cells by IL-17

BACKGROUND

The induction of epithelial cytokines/chemokines is crucial in the migration of leukocytes, and its regulatory mechanisms remain incompletely defined.

OBJECTIVE

To determine the role of IL-17, a CD4(+) T cell-derived cytokine, in modulation of primary bronchial epithelial cells, the expression of IL-6, IL-8, and intercellular adhesion molecule 1 (ICAM-1) and the potential involvement of mitogen-activated protein (MAP) kinases in IL-17-mediated signaling were examined.

METHODS

The levels of gene expression and protein production for IL-6 and IL-8 in IL-17-treated cells, in the presence or absence of MAP kinase inhibitors, were analyzed by RT-PCR and ELISA, respectively, and activation of MAP kinases was determined by Western blot analyses.

RESULTS

We showed first that IL-17 induced time-dependent expression of IL-6 and IL-8 but not of the chemokines eotaxin and RANTES. In addition, IL-17 induced activation of extracellular signal-regulated kinase 1/2 but not of p38 or JNK kinases. A selective MAP kinase kinase inhibitor, PD98059, inhibited IL-17-induced IL-6 and IL-8. A combination of IL-17 and each of the cytokines IL-4, IL-13, and IFN-gamma further enhanced IL-8 expression. IL-17 alone did not induce ICAM-1 expression and showed no effect on IL-4- or IL-13-induced ICAM-1 expression. In contrast, a combination of IL-17 and IFN-gamma augmented IL-6 and ICAM-1 expression.

CONCLUSION

These findings suggest that IL-17, alone or in combination with other cytokines, modulates airway inflammation via-in part-the expression of epithelial IL-6, IL-8, and ICAM-1.

Identification of a novel cytokine, ML-1, and its expression in subjects with asthma

A novel gene, designated ML-1, was identified from a human genomic DNA clone and human T cell cDNA sequences. The second exon of ML-1 gene shares significant sequence identity with the gene encoding IL-17 (IL-17). ML-1 gene expression was up-regulated in activated PBMCs, CD4(+) T cells, allergen-specific Th0, Th1, and Th2 clones, activated basophils, and mast cells. Increased expression of the ML-1 gene, but not IL-17, was seen following allergen challenge in four asthmatic subjects, suggesting its role in allergic inflammatory responses. ML-1 from transiently transfected COS-7 cells was able to induce gene expression and protein production for IL-6 and IL-8 (at 10 ng/ml of ML-1: for IL-6, 599.6 +/- 19.1 pg/ml; for IL-8, 1724.2 +/- 132.9 pg/ml; and at 100 ng/ml of ML-1: for IL-6, 1005.3 +/- 55.6 pg/ml; for IL-8, 4371.4 +/- 280.5 pg/ml; p < 0.05 for both doses vs baseline) in primary bronchial epithelial (PBE) cells. Furthermore, increased expression of ICAM-1 was found in ML-1-stimulated PBE cells (mean fluorescence intensity (MFI) = 31.42 +/- 4.39 vs baseline, MFI = 12.26 +/- 1.77, p < 0.05), a functional feature distinct from IL-17 (MFI = 11.07 +/- 1.22). This effect was not inhibited by a saturating amount of IL-17. These findings demonstrate that ML-1 is a novel cytokine with a distinct function, and suggest a different receptor for ML-1 on PBE cells.

Cutting edge: altered pulmonary eosinophilic inflammation in mice deficient for Clara cell secretory 10-kDa protein

Clara cell secretory protein (CC10) is a steroid-inducible protein, and its in vivo function is currently unclear. The role of CC10 in modulation of pulmonary allergic inflammation was examined in mice deficient for the CC10 gene. Wild-type and homozygous CC10-deficient mice were sensitized with an Ag, OVA, and challenged with either OVA or saline. When compared with that seen in wild-type mice, a significantly higher level of pulmonary eosinophilia was found in Ag-sensitized and challenged CC10-deficient mice. Significantly increased levels of Th2 cytokines IL-4, IL-5, IL-9, and IL-13 were also found in CC10-deficient mice. In addition, an increased level of eotaxin, but not RANTES, was also seen in CC10-deficient mice. No significant difference was observed in the level of a Th1 cytokine, IFN-gamma, between different groups of mice. These results provided the first in vivo evidence that CC10 plays a role in the modulation of pulmonary allergic inflammation.

The human mast cell: functions in physiology and disease

Mast cells are multifunctional, tissue-dwelling cells capable of secreting a wide variety of mediators. They develop from bone marrow-derived progenitor cells, primed with stem cell factor (SCF), which mediates its actions by interacting with the SCF receptor or c-kit on the cell surface. Mast cells continue their maturation and differentiation in peripheral tissue, developing into two well described subsets of cells, MCT and MCTC cells, varying in content of tryptase and chymase as well as in immunobiology. Mast cells are activated by numerous stimuli, including antigen (acting via the high affinity IgE receptor, Fc?RI), superoxides, complement proteins, neuropeptides and lipoproteins resulting in activation and degranulation. Following activation, these cells express mediators such as histamine, leukotrienes and prostanoids, as well as proteases, and many cytokines and chemokines, pivotal to the genesis of an inflammatory response. Recent data suggests that mast cells may play an active role in such diverse diseases as atherosclerosis, malignancy, asthma, pulmonary fibrosis and arthritis. Mast cells directly interact with bacteria and appear to play a vital role in host defense against pathogens. Drugs, such as glucocorticoids, cyclosporine and cromolyn have been demonstrated to have inhibitory effects on mast cell degranulation or mediator release.

New method for predicting efficiency of heating by measuring bioimpedance during radiofrequency catheter ablation in humans

INTRODUCTION

Efficiency of heating (defined as the average temperature divided by the average power) during radiofrequency (RF) catheter ablation (RFCA) can be predicted by the electrode-tissue contact pressure before RFCA. To predict the efficiency of heating during RFCA, we prospectively measured bioimpedance and correlated the bioimpedance with the efficiency of heating in patients undergoing RFCA for supraventricular tachycardias.

METHOD AND RESULTS

Of 239 RF applications in 55 patients, bioimpedance was measured from the distal pair of the electrodes of the ablation catheter using an extremely low current (10 microA at 45 kHz). Tip electrode temperature was measured with a closed-loop RF generator. Efficiency of heating and the difference (delta bioimpedance) between preablation bioimpedance (measured from the target ablation site) and baseline bioimpedance (measured in the right atrium without tissue contact) were calculated. There was significant positive correlation between preablation bioimpedance and efficiency of heating (regression coefficient = 0.053; P = 0.003) and between delta bioimpedance and efficiency of heating (regression coefficient = 0.067; P = 0.003). The highest degree of correlation was found during RFCA of the accessory pathways in the left free wall (regression coefficient = 0.14; P < 0.01). With preablation delta bioimpedance >21.5 ohms, applications targeted at the left free-wall, left posteroseptal, or right septal accessory pathways had a greater likelihood of achieving effective tissue heating (defined as maximal temperature achieved >55 degrees C).

CONCLUSION

Both preablation bioimpedance and delta bioimpedance have positive correlation with efficiency of heating during RFCA of supraventricular tachycardia. Measuring preablation bioimpedance appears to be a useful tool for predicting the efficiency of heating during RFCA.

Influenza virus A stimulates expression of eotaxin by nasal epithelial cells

BACKGROUND

Respiratory virus is one of the most common causes of airway inflammation, but its pathogenic mechanisms are not well understood. Eotaxin is a potent eosinophil chemoattractant and is a selective agonist for C-C chemokine receptor 3 (CCR3). Although it has recently been demonstrated that epithelial cells express eotaxin, both in vivo and in vitro, there are few data concerning the expression in viral infection.

OBJECTS

We hypothesized that eotaxin may play an important role in attracting inflammatory cells into the airway after viral infection and analysed whether viral infection induces eotaxin in nasal epithelial cells in vitro.

METHODS

Nasal epithelial cells obtained from polypectomy for nasal polyp were infected with influenza virus A (subtype H3N2). The cells and supernatants were collected 8, 24 and 48 h after infection. Eotaxin mRNA was analysed by RT-PCR. Eotaxin concentration in the supernatants was analysed by enzyme-linked immunosorbent assay. We also examined a blocking assay to analyse the intervention of pro-inflammatory cytokines, TNF-alpha and IL-1beta in eotaxin production induced by influenza virus.

RESULTS

The results showed that eotaxin was expressed constitutively in uninfected cells, but was up-regulated for both mRNA and protein levels in infected cells. Blocking experiments using anti-TNF-alpha and anti-IL-1beta antibodies showed no effects of these agents on the level of eotaxin. In addition, UV-inactivated virus did not enhance the expression of eotaxin.

CONCLUSIONS

These results suggest that influenza virus A infection in nasal epithelial cells stimulates the expression of eotaxin, and may play an important role in the pathogenesis of airway inflammation by inducing eotaxin.

Genome-wide linkage analyses of total serum IgE using variance components analysis in asthmatic families

Variance components models were used to analyze total IgE levels in families ascertained though the Collaborative Study of the Genetics of Asthma (CSGA) using a genome-wide array of polymorphic markers. While IgE levels are known to be associated with clinical asthma and recognized to be under strong genetic control (here the heritability was estimated at 44-60% in the three racial groups), specific genes influencing this trait are still largely unknown. Multipoint analysis of 323 markers yielded little indication of specific regions containing a trait locus controlling total serum IgE levels (adjusted for age and gender). Although a number of regions showed LOD statistics above 1.5 in Caucasian families (chromosome 4) and in African-American families (chromosomes 2 and 4), none yielded consistent evidence in all three racial groups. Analysis of total IgE adjusted for gender, age and Allergy Index (a quantitative score of skin test sensitivity to 14 common aeroallergens) was conducted on these data. In this analysis, a much stronger signal for a trait locus controlling adjusted log[total IgE] was seen on the telomeric end of chromosome 18, but only in Caucasian families. This region accounted for most of the genetic variation in log[total IgE], and may represent a quantitative trait locus for IgE levels independent of atopic response. Oligogenic analysis accounting simultaneously for the contribution of this locus on chromosome 18 and other chromosomal regions showing some evidence of linkage in these Caucasian families (on chromosomes 2, 4 and 20) failed to yield significant evidence for interaction.

Profiling of differential gene expression in activated, allergen-specific human Th2 cells

Th2 cells play a pivotal role in the pathogenesis of allergic diseases, including asthma, but the molecular basis of the Th1/Th2 dichotomy and the precise molecular pathways leading to Th2-dominant immune responses are still unclear. To this end, we have combined suppression subtractive hybridization (SSH) and high throughput analysis of cDNA arrays spotted with IMAGE clones to determine the profile of differential gene expression in human allergen-specific Th2 cells. Allergen-stimulated Th2 cells were used as the tester, and either resting Th2 cells or stimulated Th1 cells were used as the driver. SSH was used to equalize different mRNA levels and remove common sequences between the tester and the driver. Comparison of cDNA arrays probed with subtracted tester and non-subtracted driver provided a profile of Th2-selective gene expression. Analysis of 77 sequence-confirmed and differentially expressed genes in Th2 cells showed predominant EST sequences, representing 80% of sequences analyzed. The pattern of gene expression in 19 selected sequences was further analyzed in additional Th1 and Th2 clones. A total of 15 sequences showed predominant expression in Th2 cells, while the remaining four EST sequences showed no detectable amplification signal. The database containing Th2-selective genes will further our understanding of Th2 cell function and the genetic basis of allergic diseases.

Global distribution of atrial ectopic foci triggering recurrence of atrial tachyarrhythmia after electrical cardioversion of long-standing atrial fibrillation: a bi-atrial basket mapping study

OBJECTIVES

The objective of this study was to assess the spatial distribution of atrial ectopic foci potentially triggering recurrent atrial tachyarrhythmias after electrical cardioversion of long-standing atrial fibrillation (AF).

BACKGROUND

It remains unknown whether targeted ablation of atrial ectopic foci concentrated in the pulmonary veins is feasible in patients with long-standin

Reversal of deteriorated fractal behavior of heart rate variability by beta-blocker therapy in patients with advanced congestive heart failure

INTRODUCTION

The slope of the power spectrum in heart rate variability (HRV) reflects the fractal or scaling behavior in HR dynamics and recently was confirmed as an independent predictor of postmyocardial infarction survival. Whether or not the new measurement in HRV foresees the functional evolution in patients with advanced congestive heart failure treated by beta blockers is unclear.

METHODS AND RESULTS

Sequential 24-hour Holter ECG recordings were obtained at baseline, and 1 and 3 months after addition of atenolol therapy for advanced congestive heart failure in 10 patients. The slope and intercept of the regression line of power-law behavior, the short- and intermediate-term of detrended fluctuated analysis (DFA), the approximate entropy (ApEn), and the standard frequency spectra of the 24-hour HRV were compared sequentially as well as with those in 12 age-matched normal controls. The results showed that the slope (-1.70 +/- 0.45 vs -1.22 +/- 0.21; P < 0.05) and the intercept (5.11 +/- 0.46 vs 5.62 +/- 0.24; P < 0.05) of the regression line of power-law behavior and the short-term DFA (for 4 to 11 beats) (0.78 +/- 0.18 vs 1.13 +/- 0.21; P < 0.05) increased after 3 months of atenolol treatment. However, the change in intermediate-term DFA (>11 beats) and ApEn was not apparent (1.24 +/- 0.21 vs 1.22 +/- 0.15 and 1.34 +/- 0.14 vs 1.36 +/- 0.11; both P > 0.05). The evolution of the slope or intercept of the regression line of the HRV power spectrum did not correlate with the echocardiographic or clinical cardiac function, or with the frequency spectral components of the HRV (P > 0.05).

CONCLUSION

Additional beta-blocker therapy upregulated the fractal behavior control of the HRV in patients with advanced congestive heart failure. The improvement was independent of subjective and objective global cardiac performance.

Antibody targeting of doxorubicin-loaded liposomes suppresses the growth and metastatic spread of established human lung tumor xenografts in severe combined immunodeficient mice

Beta1 integrins, expressed on the cell surface of human non-small cell lung carcinomas, are used here as a target for the selective delivery of anti-cancer drug-loaded liposomes. Fab' fragments of a monoclonal antibody specific for human beta1 integrins were conjugated to sterically stabilized liposomes. Confocal microscopy of beta1 integrin-positive lung tumor cells incubated with fluorescently labeled anti-beta1 Fab immunoliposomes revealed a tumor-specific binding and efficient internalization of the liposomes into the tumor cells. The ability of these liposomes to deliver cytotoxic drugs to the tumor and kill these cells was demonstrated in vitro by incubating tumor cells with doxorubicin-loaded anti-beta1 Fab' immunoliposomes. The drug-loaded immunoliposomes were >30-fold more cytotoxic to the tumor cells than drug-loaded liposomes without antibody, nonspecific Fab' control immunoliposomes with drug or immunoliposomes without drug. The therapeutic efficacy of doxorubicin-loaded immunoliposomes was also evaluated in a metastatic human lung tumor xenograft/severe combined immunodeficient (SCID) mouse model. SCID mice that received i.v. injections of human lung tumor cells developed primary tumor nodules in the lung that subsequently metastasized to the liver and adrenal gland. Treatment of SCID mice bearing established lung tumor xenografts with doxorubicin-loaded anti-beta1 Fab immunoliposomes resulted in a significant suppression of tumor growth (monitored periodically by quantifying serum levels of a tumor marker), whereas tumors grew progressively in mice treated with control formulations. In addition to suppressing the growth of the primary lung tumor nodules, the immunoliposomes prevented the metastatic spread of the tumor to the liver and adrenal glands and increased the median survival time of the tumor-bearing mice. We conclude that Fab' immunoliposomes directed to tumor-associated integrins represent a potentially viable approach clinically for the selective delivery of drugs to solid tumors and may be useful in preventing the metastatic spread of lung cancer.

IL-10 kinetics in thyroiditis-prone BB/Wor rats

Cytokines modulate the course of autoimmunity, but their role in the evolution of spontaneous disease is unclear. This study compared the cytokine kinetics of T cell cultures from thyroiditis (LT)-prone NB line BB/Wor rats with those of Wistar (Wis) rat controls following activation with the thyroid-specific antigen thyroglobulin (Tg) or Concanavalin A (Con A).

DESIGN

T cell enhanced splenocytes from 60 day old Wis and NB rats were activated with 0.5 microg/ml rat thyroglobulin (Tg) or Con A in the presence of homologous irradiated splenocytes as antigen presenting cells (APC's). In addition, the effect of APC's was determined in a crisscross experiment which examined NB T cell responses to Con A in the presence of Wis APC's. ELISA and RT-PCR were used to examine IL-2, IL-4, IL-10, TNFalpha, IFNgamma, IL-I0 concentrations and mRNA expression in the supernatant and cells from parallel cultures harvested at specific intervals. Frozen thyroids from 60 day old NB, Wis and Fisher rats were examined for the presence of IL-10 by immunohistochemistry. T cell proliferation was measured by 3H thymidine uptake.

RESULTS

Following activation with either Tg or Con A, IL-10 concentrations exceeded IFNgamma in NB rat cultures, but IFNgamma exceeded IL-10 in Wis cultures. Wis splenocytes significantly enhanced NB T cell proliferation and cytokine responses to Con A. Thyroids from 60 day NB rats contained IL-10, but no IFNgamma. There was no IL-10 in thyroids from Wistar or Fisher rats.

CONCLUSION

Splenocyte responses in LT-prone BB/Wor rats favor IL-10 production. Future investigations will examine the source of intrathyroidal IL-10 and its role in LT.

Association and linkage of atopic dermatitis with chromosome 13q12-14 and 5q31-33 markers

Atopic dermatitis is a chronic inflammatory skin disease that affects 10-20% of the population. Linkage of atopy, asthma, allergic rhinitis, and total serum IgE levels to several different chromosomal regions have been described extensively, but little is known about the genetic control of atopic dermatitis. We tested for the association and linkage between atopic dermatitis and five chromosomal regions: 5q31-33, 6p21.3, 12q15-24.1, 13q12-31, and 14q11.2/14q32.1-32.3. Marker analysis was performed in two Caucasian populations: (i) 192 unrelated German children with atopic dermatitis and 59 non-atopic children from a German birth cohort study (MAS'90), parental DNA was tested in 77 of 192 children with atopic dermatitis; (ii) 40 Swedish families with at least one family member with atopic dermatitis selected from the International Study of Asthma and Allergy in Children. Evidence for linkage and allelic association for atopic dermatitis was observed for markers on chromosome 13q12-14 and 5q31-33.

Successful treatment of aconitine induced life threatening ventricular tachyarrhythmia with amiodarone

With the increasing trend of cross mixing of populations, aconitine induced poisoning and its related arrhythmias may be more frequently encountered worldwide. However, the clinical experience is often too limited to draw any conclusion on the optimal treatment for tachycardia induced by aconitine intoxication. The clinical presentation, serial electrocardiographic changes, and responses to antiarrhythmic agents are reported in a patient with aconitine induced life threatening ventricular tachyarrhythmia. Amiodarone was effective in suppressing polymorphic ventricular tachycardia, which might provide an example of successful pharmacological intervention in aconitine induced ventricular tachyarrhythmia.

Changes in the mRNA levels of delayed rectifier potassium channels in human atrial fibrillation

INTRODUCTION

We measured mRNA levels of delayed rectifier potassium channels in human atrial tissue to investigate the mechanism of the shortening of the atrial effective refractory period and the loss of rate-adaptive shortening of the atrial effective refractory period in human atrial fibrillation.

METHODS AND RESULTS

A total of 34 patients undergoing open heart surgery were included. Atrial tissue was obtained from the right atrial free wall, right atrial appendage, left atrial free wall and left atrial appendage, respectively. The mRNA amounts of KVLQT1 (IKs), minK (beta-subunit of IKs), HERG (IKr), and KV1.5 (IKur) were measured by reverse transcription-polymerase chain reaction and normalized to the mRNA amount of GAPDH. We found that the mRNA levels of KV1.5, HERG and KVLQT1 were all significantly decreased in patients with persistent atrial fibrillation for more than 3 months. In contrast, the mRNA level of minK was significantly increased in patients with persistent atrial fibrillation for more than 3 months. We further showed that these changes were independent of the underlying cardiac disease, atrial filling pressure, gender and age. We also found that there was no spatial dispersion of mRNA levels among the four atrial sampling sites.

CONCLUSIONS

Because the decrease in potassium currents results in a prolonged action potential, the shortening of the atrial effective refractory period in atrial fibrillation should be attributed to other factors. However, the decrease in IKs might contribute, at least in part, to the loss of rate-adaptive shortening of the atrial refractory period.

An IL13 coding region variant is associated with a high total serum IgE level and atopic dermatitis in the German multicenter atopy study (MAS-90)

BACKGROUND

Allergic diseases are one of the major causes of morbidity in the developed countries today, and the prevalence of these diseases is increasing steadily. Study of total serum gE level is important in understanding the genetics of allergic iseases because IgE levels are considered to be a crucial pathogenic component. IL-13 plays an important role in the induction of IgE synthesis and in the pathogenesis of allergic diseases.

OBJECTIVE

We sought to examine potential variation at the IL13 gene and estimate its effect on elevated IgE level and atopic dermatitis (AD).

METHODS

We conducted mutational analyses of the IL13 gene by using single-stranded conformation polymorphism and DNA sequencing. Case control studies for high-IgE phenotype and AD were performed by using subjects from the German MAS-90 cohort.

RESULTS

A novel IL13 coding region variant at 4257 bp (G to A, fourth exon) was identified. Case control studies of a German sample from the MAS-90 cohort showed significant associations between the presence of the A allele and two atopic phenotypes: high IgE (odds ratio, 2.38; 95% confidence interval, 1.35-4.21; P =.0026) and AD (odds ratio, 1.77; 95% confidence interval, 1.06-2.96; P =.03).

CONCLUSION

This IL13 coding region variant may be involved in the pathogenesis of AD and high total serum IgE level in a study population of white subjects.

Intravenous sotalol decreases transthoracic cardioversion energy requirement for chronic atrial fibrillation in humans: assessment of the electrophysiological effects by biatrial basket electrodes

OBJECTIVES

This study was undertaken to assess the effects of sotalol on the transthoracic cardioversion energy requirement for chronic atrial fibrillation (AF) and on the atrial electrograms during AF recorded by two basket electrodes.

BACKGROUND

The effects of sotalol infusion on transthoracic electrical cardioversion for chronic atrial fibrillation in humans have not been well investigated.

METHODS

We included 18 patients with persistent AF for more than three months. Atrial electrograms were recorded by two basket electrodes positioned in each atrium respectively. Transthoracic cardioversion was performed before and after sotalol 1.5 mg/kg i.v. infusion.

RESULTS

In the 14 patients whose AF could be terminated by cardioversion before sotalol infusion, the atrial defibrillation energy was significantly reduced after sotalol infusion (236 +/- 74 jules [J] vs. 186 +/- 77 J; p < 0.01). Atrial fibrillation was refractory to cardioversion in four patients at baseline and was converted to sinus rhythm by cardioversion after sotalol infusion in two of them. We further divided the patients into two groups. Group A consisted of 10 patients in whom the energy requirement was decreased by sotalol while group B consisted of eight patients in whom the energy requirement was not decreased. The mean A-A (atrial local electrogram) intervals during AF were significantly increased after sotalol infusion in both groups, but the increment of A-A interval was significantly larger in group A than it was in group B patients (36 +/- 13 ms vs. 22 +/- 8 ms for the right atrium; 19 +/- 7 ms vs. 9 +/- 7 ms for the left atrium; both p < 0.05). The spatial and temporal dispersions of A-A intervals were not significantly changed after sotalol infusion in both atria in both groups.

CONCLUSIONS

Sotalol decreases the atrial defibrillation energy requirement by increasing atrial refractoriness but not by decreasing the dispersion of refractoriness.

Distal end of the atrioventricular nodal artery predicts the risk of atrioventricular block during slow pathway catheter ablation of atrioventricular nodal re-entrant tachycardia

OBJECTIVE

To search for a reliable anatomical landmark within Koch's triangle to predict the risk of atrioventricular (AV) block during radiofrequency slow pathway catheter ablation of AV nodal re-entrant tachycardia (AVNRT).

PATIENTS AND METHODS

To test the hypothesis that the distal end of the AV nodal artery represents the anatomical location of the AV node, and thus could be a useful landmark for predicting the risk of AV block, 128 consecutive patients with AVNRT receiving slow pathway catheter ablation were prospectively studied in two phases. In phase I (77 patients), angiographic demonstration of the AV nodal artery and its ending was performed at the end of the ablation procedure, whereas in the subsequent phase II study (51 patients), the angiography was performed immediately before catheter ablation to assess the value of identifying this new landmark in reducing the risk of AV block. Multiple electrophysiologic and anatomical parameters were analysed. The former included the atrial activation sequence between the His bundle recording site (HBE) and the coronary sinus orifice or the catheter ablation site, either during AVNRT or during sinus rhythm. The latter included the spatial distances between the distal end of the AV nodal artery and the HBE and the final catheter ablation site, and the distance between the HBE and the tricuspid border at the coronary sinus orifice floor.

RESULTS

In phase I, nine of the 77 patients had complications of transient (seven patients) or permanent (two patients) complete AV block during stepwise, anatomy guided slow pathway catheter ablation. These nine patients had a wider distance between the HBE and the distal end of the AV nodal artery, and a closer approximation of the catheter ablation site to the distal end of the AV nodal artery, which independently predicted the risk of AV block. In contrast, none of the available electrophysiologic parameters were shown to be reliable. When the distance between the distal end of the AV nodal artery and the ablation target site was more than 2 mm, the complication of AV block virtually never occurred. In phase II, all 51 patients had successful elimination of the slow pathways without complication when the ablation procedure was guided by preceding angiography with identification of the distal end of the AV nodal artery.

CONCLUSIONS

The distal end of the AV nodal artery shown by angiography serves as a useful landmark for the prediction of the risk of AV block during slow pathway catheter ablation of AVNRT.

Interferon-beta induces selective enhancement of antigen-specific T cell responses

Interferon-beta (IFN-beta) inhibits mitogen-induced T cell responses, in part through downregulation of interleukin-12 (IL-12) or upregulation of IL-10. We have reexamined these findings using ragweed (RW) stimulated or tetanus toxoid (TT)-stimulated human peripheral blood mononuclear cells (PBMC) and nontransformed, antigen-specific, human Th0, Th1, and Th2 clones. IFN-beta induced concentration-dependent inhibition of phytohemagglutinin (PHA)-stimulated PBMC proliferation and enhancement of RW-stimulated or TTstimulated PBMC proliferation. Monocyte depletion of PBMC isolates resulted in concentration-dependent inhibition of RW-driven or TT-driven proliferation by IFN-beta. This response was unaltered by the addition of either exogenous recombinant human IL-12 (rHuIL-12) or saturating concentrations of anti-IL-10. Moreover, addition of exogenous rHuIL-10 to nondepleted RW-driven or TT-driven PBMC cultures did not alter the concentration-dependent enhancement of antigen-driven proliferation induced by IFN-beta. Th0, Th1, and Th2 clones stimulated in the presence of antigen and autologous, irradiated PBMC displayed concentration-dependent inhibition of proliferation in the presence of IFN-beta that was unaltered by the addition of either exogenous rHuIL-12 or a saturating concentration of anti-IL-10. Finally, whereas IFN-beta inhibited antigen-driven generation of IL-5, IL-12, IL-13, and IFN-gamma, IFN-beta enhanced generation of both IL-4 and IL-10. Thus, IFN-beta, induces a selective, IL-10-independent and IL-12-independent upregulation of antigen-specific T cell responses, supporting the role of IFN-beta as an immunomodulatory rather than an antiproliferative/immunosuppressive cytokine.

Remodeling of the vascular bed and progressive loss of capillaries in denervated skeletal muscle

Very little is known regarding structural and functional responses of the vascular bed of skeletal muscle to denervation and about the role of microcirculatory changes in the pathogenesis of post-denervation muscle atrophy. The purpose of the present study was to investigate the changes of the anatomical pattern of vascularization of the extensor digitorum longus muscle in WI/HicksCar rats 1, 2, 4, 7, 12, and 18 months following denervation of the limb. We found that the number of capillaries related to the number of muscle fibers, i.e. the capillary-to-fiber ratio (CFR), decreased by 88%, from 1.55 +/- 0.35 to 0.19 +/- 0.04, during the first 7 months after denervation and then slightly declined at a much lower rate during the next 11 months of observation to 10% of the CFR in normal muscle. Between months 2 and 4 after denervation, the CRF decreased by 2.4 times, from 58% to 24% of the control value. The loss of capillaries during the first 4 months following nerve transection was nearly linear and progressed with an average decrement of 4.16% per week. Electron microscopy demonstrated progressive degeneration of capillaries following nerve transection. In muscle cells close to degenerating capillaries, the loss of subsarcolemmal and intermyofibrillar mitochondria, local disassembly of myofibrils and other manifestations of progressive atrophy were frequently observed. The levels of devascularization and the degree of degenerative changes varied greatly within different topographical areas, resulting in significant heterogeneity of intercapillary distances and local capillary densities within each sample of denervated muscle. Perivascular and interstitial fibrosis that rapidly developed after denervation resulted in the spatial separation of blood vessels from muscle cells and their embedment in a dense lattice of collagen. As a result of this process, diffusion distances between capillaries and the surfaces of muscle fibers increased 10-400 times. Eighteen months after denervation most of the capillaries were heavily cushioned with collagen, and on the average 40% of the muscle cells were completely avascular. Devascularization of the tissue was accompanied by degeneration and death of muscle cells that had become embedded in a dense lattice of collagen. Immunofluorescent staining for the vascular isoform of alpha-actin revealed preservation of major blood vessels and a greater variability in thickness of their medial layer. Hyperplastic growth of the medial layer in some blood vessels resulted in narrowing of their lumens. By the end of month 7 after denervation, large deposits of collagen around arterioles often exceeded their diameters. Identification of oxidative muscle fibers after immunostaining for slow-twitch myosin, as well as using ultrastructural criteria, has shown that after 2 months of denervation oxidative muscle fibers were less susceptible to atrophy than glycolytic fibers. The lower rate of atrophy of type I muscle fibers at early stages of denervation may be explained by their initially better vascularization in normal muscle and their higher capacity to retain capillaries shortly after denervation. Thus, degeneration and loss of capillaries after denervation occurs more rapidly than the loss of muscle fibers, which results in progressive decrease of the CFR in denervated muscle. The change of capillary number in denervated muscle is biphasic: the phase of a rapid decrease of the CFR during the first 7 months after nerve transection is followed by the phase of stabilization. The presence of areas completely devoid of capillaries in denervated muscle and the virtual absence of such areas in normal muscle indicate the development of foci of regional hypoxia during long-term denervation. The anatomical pattern of muscle microvascularization changes dramatically after nerve transection. Each muscle fiber in normal muscle directly contacts on average 3-5 capillaries. (ABSTRACT TRUNCATED)

Interleukin-13 modulates collagen homeostasis in human skin and keloid fibroblasts

Interleukin (IL)-13 has been implicated in the pathogenesis of various diseases characterized by fibrosis. We describe the effects of IL-13 on collagen homeostasis from normal (NF) and keloid (KF) fibroblasts and compare these effects with those of IL-4 and transforming growth factor (TGF)-beta(1). Total collagen generation was up-regulated in NF after 48 h of stimulation by IL-13; in KF, IL-13 stimulated a more rapid collagen response. The kinetics and magnitude of collagen generation induced by IL-13 were equivalent to those induced by similar concentrations of IL-4 and TGF-beta(1). Collagen type I production paralleled total collagen generation from both NF and KF; however, IL-4-induced collagen type I and total collagen production from KF was more transient than that induced by either IL-13 or TGF-beta(1). Procollagen 1alpha1 gene expression was induced in KF by stimulation with IL-13 for 24 h. Moreover, IL-13 was unique among these three cytokines in its ability to induce gene expression for procollagen 3alpha1. Finally, IL-13 inhibited IL-1beta-induced matrix metalloproteinase (MMP)-1 and MMP-3 production and enhanced tissue inhibitor of metalloproteinase (TIMP)-1 generation from NF; although similar effects were observed with IL-4, TGF-beta(1) transiently enhanced MMP-1 and MMP-3 generation without effecting TIMP-1. In KF, IL-13 and IL-4 inhibited MMP-3, whereas TGF-beta(1) enhanced MMP-3; TIMP-1 was unaffected by any of the three cytokines. These data demonstrate both the profibrotic effects of IL-13 on collagen homeostasis and the potential differential regulation of collagen homeostasis in fibroblast subtypes by IL-13.

Atopic dermatitis is associated with a functional mutation in the promoter of the C-C chemokine RANTES

Up-regulation of C-C chemokine expression characterizes allergic inflammation and atopic diseases. A functional mutation in the proximal promoter of the RANTES gene has been identified, which results in a new consensus binding site for the GATA transcription factor family. A higher frequency of this allele was observed in individuals of African descent compared with Caucasian subjects (p < 0.00001). The mutant allele was associated with atopic dermatitis in children of the German Multicenter Allergy Study (MAS-90; p < 0.037), but not with asthma. Transient transfections of the human mast cell line HMC-1 and the T cell line Jurkat with reporter vectors driven by either the mutant or wild-type RANTES promoter showed an up to 8-fold higher constitutive transcriptional activity of the mutant promoter. This is the first report to our knowledge of a functional mutation in a chemokine gene promoter. Our findings suggest that the mutation contributes to the development of atopic dermatitis. Its potential role in other inflammatory and infectious disorders, particularly among individuals of African ancestry, remains to be determined.

Genetic markers of atopy in infancy: results from the German Multicenter Allergy Study

Genetic studies of atopy-associated traits require unambiguous phenotypes to avoid both type 1 and 2 errors. The German Multicenter Allergy Study has provided a birth cohort with longitudinally well defined and stable phenotypes. We summarize data on candidate gene studies on chromosomes 12q, 5q, and 13q using high total IgE and atopic dermatitis (AD) as the most common atopy associated phenotypes in early childhood. We also present data on a functional RANTES promoter polymorphism that we recently identified. A significantly higher frequency of the mutant allele was seen in individuals of African descent compared to Caucasian subjects. In addition, an association of the polymorphism with AD could be demonstrated in the MAS cohort. Although the statistical approaches are limited, the MAS cohort has provided a valuable population for candidate gene studies in atopy.

RNA melanoma vaccine: induction of antitumor immunity by human glycoprotein 100 mRNA immunization

An RNA melanoma vaccine was investigated to induce protective immunity in a mouse-melanoma model. LacZ mRNA was synthesized in vitro by pSFV3 expression vector and introduced into the spleen of mice, using HVJ-liposomes. A high level of beta-galactosidase activity was detected for 10 days in mouse spleen. The human melanoma-associated antigen gp100 mRNA was synthesized in vitro by pSFV3 vector and encapsulated in HVJ-liposomes. Immunization by direct injection of the gp100 mRNA HVJ-liposomes into mouse spleen induced both anti-gp100 Ab and CTL responses against B16 melanoma. Immunization by administration of gp100 mRNA into the spleen delayed tumor growth and significantly prolonged survival compared with control treated mice. These preclinical studies demonstrate that an RNA tumor antigen vaccine strategy has potential application for human cancer treatment and prevention.

Regulation of antigen-induced human T-lymphocyte responses by calcineurin antagonists

BACKGROUND

Cyclosporin A (CS) and tacrolimus (FK506, FK) are calcineurin antagonists used widely as T-cell immunosuppressants; however, their relative efficacy on antigen-stimulated T-cell subsets remains undefined.

OBJECTIVE

We have examined the effects of CS and FK on antigen-driven proliferation and cytokine generation from human PBMCs and T-cell clones.

METHODS

Proliferation was assessed by tritiated thymidine incorporation. Cytokine generation was assessed by reverse transcription-PCR and ELISA.

RESULTS

Ragweed- and tetanus toxoid-driven proliferation of PBMCs was down-regulated equally by CS or FK. Gene expression for proinflammatory cytokines (IL-4, IL-5, IL-13, and IFN-gamma) assessed by reverse transcription-PCR was down-regulated in a concentration-dependent manner by either drug. Antigen-induced proliferation of ragweed-specific Th0, Th1, or Th2 clones was inhibited by either CS or FK. Cytokine gene expression and protein secretion into culture supernatants (IL-4, IL-5, IL-13, and IFN-gamma) were down-regulated in a concentration-dependent manner by either CS or FK in all relevant T-cell subsets. Interestingly, down-regulation of IL-5 protein generation from Th0 and Th2 clones was consistently less sensitive to either drug than was the effect on either IL-4 or IL-13 protein generation.

CONCLUSION

CS and FK promote equivalent down-regulation of Th0, Th1, and Th2 responses; however, IL-5 generation is relatively insensitive to the immunomodulatory effects of calcineurin antagonists.

Usefulness of intravenous propofol anesthesia for radiofrequency catheter ablation in patients with tachyarrhythmias: infeasibility for pediatric patients with ectopic atrial tachycardia

General anesthesia is sometimes required during radiofrequency catheter ablation (RFCA) of various tachyarrhythmias because of an anticipated prolonged procedure and the need to ensure stability during critical ablation. In this study, we examine the feasibility of using propofol anesthesia for RFCA procedure. There were 150 patients (78 male, 72 female; mean age 30 years, range 4-96 years) in the study. Electrophysiologic study was performed before and during propofol infusion in the initial 20 patients and was performed only during propofol infusion in the remaining 130 patients. In the initial 20 patients, propofol infusion increased the sinus rate and facilitated AV nodal conduction. The accessory pathway effective refractory period, as well as the sinus node recovery time, atrial effective refractory period, and ventricular effective refractory period were not significantly changed. There were 152 tachyarrhythmias in 150 patients (24 atrial flutter, 31 AV nodal reentrant tachycardia, 68 AV reciprocating tachycardia, 12 ventricular tachycardia, and 17 atrial tachycardia). Most (148/152) tachycardias remained inducible after anesthesia and RFCA was performed uneventfully. However, in four of the seven pediatric patients with ectopic atrial tachycardia, the tachycardia terminated after propofol infusion and could not be induced by isoproterenol infusion. Consequently, RFCA could not be performed. Intravenous propofol anesthesia is feasible during RFCA for most tachyarrhythmias except for ectopic atrial tachycardia in children.

New detachable poly(ethylene glycol) conjugates: cysteine-cleavable lipopolymers regenerating natural phospholipid, diacyl phosphatidylethanolamine

A new strategy for the reversible attachment of methoxypoly(ethylene glycol) (mPEG) to an amino-containing substrate is described. The strategy is based on formation of a benzyl carbamate linkage substituted with a disulfide in the para or ortho position. While being stable under nonreducing conditions, the dithiobenzyl (DTB) urethane linkage is susceptible to cleavage by mild thiolysis with cysteine resulting in release of the parent amino component of the conjugate in its original form. The method is exemplified by preparation of mPEG-DTB-alcohol, its activation and attachment to distearoylphosphatidylethanolamine (DSPE). The resulting lipopolymer incorporates into liposomes, which are capable of losing their polymer coating under conditions approximating those existing in vivo. Implications for drug delivery are briefly discussed.

Determination of Duffy genotypes in three populations of African descent using PCR and sequence-specific oligonucleotides

The expression of the Duffy Antigen/Receptor for Chemokines (DARC) on red blood cells (RBC) has been commonly determined using hemagglutination tests. Because the vast majority of African individuals are Duffy-negative, screening for DARC expression on RBC is a valuable tool to assess Caucasian admixture in populations of African descent. Furthermore, blood group antigens have been frequently tested as potential risk factors for complex diseases. We established a dot-blotting protocol using sequence-specific oligonucleotides (SSOs) for the DARC-46T ("Duffy-positive") and -46C ("Duffy-negative") alleles. With this method, but not with serological methods, Duffy-positive individuals can be further characterized as homozygous or heterozygous for the dominant Duffy-positive allele, allowing more precise estimation of allele frequencies and admixture in heterogeneous populations. In unrelated African American (n = 235), Afro-Caribbean (n = 90) and Colombian (n = 93) subjects, the frequency of the -46T allele was 21.7%, 12.2% and 74.7%, respectively. The percentage of Duffy-positive individuals (homozygous or heterozygous for the -46T allele) in each population was in accordance with published frequencies. As expected, the -46C allele was not detected in 20 Caucasian subjects. This sensitive and specific method allows for the rapid and inexpensive screening of large samples for Duffy genotypes using small quantities of genomic DNA.

Consulting with radiologists outside the hospital by using Java

A Java-based teleradiology system that makes use of the Internet has been developed. Using this system, an on-call, off-duty radiologist can make diagnoses and perform consultations easily by reviewing the transferred images at home. The image accessibility of the system allows a hospital with such a system to assist an affiliated rural hospital without a full-time radiologist. The system consists of three components: the image server subsystem, the database server subsystem, and the client subsystem. All client subsystems of the system are designed to be symmetric. Users may retrieve images, manipulate them, and perform remote consultations. In addition, a user may add annotations to an image area of interest. Screen synchronization is achieved by means of the command-passing technique and local command execution to reduce the network bandwidth and transmission demands; user interaction is achieved by means of a synchronized indicator for pointing out areas of interest and dialog windows for conversation. Because Java programs can run on heterogeneous platforms, the need for system maintenance and user training is minimized. Although the drawback of Internet bandwidth still exists, the system enables platform-independent teleradiology via the Internet and allows easy and cost-effective remote consultation.

Measurement of funny current (I(f)) channel mRNA in human atrial tissue: correlation with left atrial filling pressure and atrial fibrillation

INTRODUCTION

The funny current (I(f)) contributes to phase IV spontaneous depolarization in cardiac pacemaker tissue. Enhanced I(f) activity in myocardial tissue may lead to increased automaticity and therefore tachyarrhythmia. We measured the amount of I(f) activity in the messenger ribonucleic acid (mRNA) in human atrial tissue and correlated the mRNA amount to left atrial filling pressure and atrial fibrillation (AF).

METHODS AND RESULTS

A total of 34 patients undergoing open heart surgery were included (15 men and 19 women, aged 55+/-10 years). Atrial tissue was obtained from the right atrial free wall, the right atrial appendage, the left atrial free wall, and the left atrial appendage, respectively. The mRNA amount of the I(f) channel was measured by reverse transcription polymerase chain reaction and was normalized to the mRNA levels of glyceraldehyde 3-phosphate dehydrogenase. We found that the I(f) channel mRNA was present at all the atrial sampling sites. A higher left atrial filling pressure, an indicator of congestive heart failure, was associated with a higher I(f) mRNA level (r2 = 0.446, P < 0.01 by linear regression). We also found that the mRNA amount was significantly higher in patients with AF than in patients without AF (1.68+/-0.49 vs 1.27+/-0.43; P < 0.05). Age, sex, right atrial filling pressure, left atrial dimension, and left ventricular ejection fraction had no significant effect on the mRNA level.

CONCLUSION

The mRNA of the I(f) channel is present in the free-wall area and appendage area from both atria. Increased left atrial filling pressure and clinical AF are associated with increased I(f) mRNA level.

The analysis of alkyl-capped alcohol ethoxylates and alcohol ethoxycarboxylates from alcohol ethoxylates by atmospheric pressure chemical ionization mass spectrometry

Alcohol ethoxylates (AEs) are nonionic surfactants. They are industrially important compounds that have historically been difficult to analyze, with the best results to date achieved through derivatization (e.g., silylation) followed by analysis by gas chromatography/mass spectrometry (GC/MS). Recently, mass spectrometric techniques such as field desorption (FD), time-of-flight secondary ion mass spectrometry (TOF-SIMS), fast atom bombardment (FAB), electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) have been employed to analyze surfynol(R) 4xx. In an effort to produce low-cost alkyl-capped AEs and anionic detergents from AEs, a fast and reliable measure of the product yields and conversions from AEs is required in research. We found that the product yields and conversions from reactions of AEs, obtained by the employment of atmospheric pressure chemical ionization (APCI), were in good agreement with those obtained from proton nuclear magnetic resonance spectroscopy ((1)H-NMR). Therefore, APCI can be used as a validated tool for studying AE reactions. Mixtures that contain either silylated or unsilylated ethoxylates and/or carboxylates yield the same APCI mass spectra. Copyright -Copyright 1999 John Wiley & Sons, Ltd.

Electrophysiologic study and radiofrequency catheter ablation of isthmus-independent atrial flutter

INTRODUCTION

We report the electrophysiologic study and radiofrequency catheter ablation of isthmus-independent atrial flutter in 2 patients. The isthmus-independent atrial flutter in these 2 patients had similar ECG and electrophysiologic findings. Both were reproducibly induced by rapid atrial pacing. The atrial activation sequence and entrainment study proved that these atrial flutters were not isthmus-dependent. A high-right atrial site was identified as the critical site of the slow conduction zone of the tachycardia in both. This site showed double potentials and mid-diastolic potentials. Radiofrequency catheter ablation at this site successfully eliminated the isthmus-independent atrial flutter in both patients.

Oral gene delivery with chitosan--DNA nanoparticles generates immunologic protection in a murine model of peanut allergy

Food allergy is a common and often fatal disease with no effective treatment. We describe here a new immunoprophylactic strategy using oral allergen-gene immunization to modulate peanut antigen-induced murine anaphylactic responses. Oral administration of DNA nanoparticles synthesized by complexing plasmid DNA with chitosan, a natural biocompatible polysaccharide, resulted in transduced gene expression in the intestinal epithelium. Mice receiving nanoparticles containing a dominant peanut allergen gene (pCMVArah2) produced secretory IgA and serum IgG2a. Compared with non-immunized mice or mice treated with 'naked' DNA, mice immunized with nanoparticles showed a substantial reduction in allergen-induced anaphylaxis associated with reduced levels of IgE, plasma histamine and vascular leakage. These results demonstrate that oral allergen-gene immunization with chitosan-DNA nanoparticles is effective in modulating murine anaphylactic responses, and indicate its prophylactic utility in treating food allergy.

Down-regulation of L-type calcium channel and sarcoplasmic reticular Ca(2+)-ATPase mRNA in human atrial fibrillation without significant change in the mRNA of ryanodine receptor, calsequestrin and phospholamban: an insight into the mechanism of atrial electrical remodeling

OBJECTIVES

We investigated the gene expression of calcium-handling genes including L-type calcium channel, sarcoplasmic reticular calcium adenosine triphosphatase (Ca(2+)-ATPase), ryanodine receptor, calsequestrin and phospholamban in human atrial fibrillation.

BACKGROUND

Recent studies have demonstrated that atrial electrical remodeling in atrial fibrillation is associated with intracellular calcium overload. However, the changes of calcium-handling proteins remain unclear.

METHODS

A total of 34 patients undergoing open heart surgery were included. Atrial tissue was obtained from the right atrial free wall, right atrial appendage, left atrial free wall and left atrial appendage, respectively. The messenger ribonucleic acid (mRNA) amount of the genes was measured by reverse transcription-polymerase chain reaction and normalized to the mRNA levels of glyceraldehyde 3-phosphate dehydrogenase.

RESULTS

The mRNA of L-type calcium channel and of Ca(2+)-ATPase was significantly decreased in patients with persistent atrial fibrillation for more than 3 months (0.36+/-0.26 vs. 0.90+/-0.88 for L-type calcium channel; 0.69+/-0.42 vs. 1.21+/-0.68 for Ca(2+)-ATPase; both p < 0.05, all data in arbitrary unit). We further demonstrated that there was no spatial dispersion of the gene expression among the four atrial tissue sampling sites. Age, gender and underlying cardiac disease had no significant effects on the gene expression. In contrast, the mRNA levels of ryanodine receptor, calsequestrin and phospholamban showed no significant change in atrial fibrillation.

CONCLUSIONS

L-type calcium channel and the sarcoplasmic reticular Ca(2+)-ATPase gene were down-regulated in atrial fibrillation. These changes may be a consequence of, as well as a contributory factor for, atrial fibrillation.

An economical, personal computer-based picture archiving and communication system

Taichung Veterans General Hospital has been developing a hospital-wide picture archiving and communication system (PACS) since 1993. A personal computer-based environment was implemented to reduce costs (only $2,500 for each view station) and take advantage of distributed system techniques. Other features of the PACS are automatic image acquisition, hierarchic storage management, efficient image transmission, robust fault tolerance, and user-friendly image manipulation. The system is integrated with the hospital information system so that Chinese-language patient data can be automatically transferred. A four-tier storage hierarchy and a multipath search strategy are used to improve reliability and efficiency. Image compression and efficient image transmission techniques (autorouting and prefetching) are used to reduce the response time. Robust fault tolerance is achieved with fault-tolerant hardware, image replication, and a system watchdog. User-friendly image manipulation features include easy adjustment of the brightness, contrast, or quality of the displayed image; several windows for image display; and image measurement capability. The PACS currently supports computed tomography, ultrasound, magnetic resonance imaging, computed radiography, and digital fluoroscopy; almost all appropriate personal computers in the hospital can be used as view stations. Users are satisfied with the quality, reliability, and performance of the system.

Differential regulation of antigen-induced IL-4 and IL-13 generation from T lymphocytes by IFN-alpha

BACKGROUND

IL-4 and IL-13 are related cytokines with similar functional properties. Differential regulation of IL-4 and IL-13 has not been described.

OBJECTIVE

We have examined the effects of IFN-alpha on antigen-driven proliferation, IL-4 generation, and IL-13 generation from human PBMCs and T-cell clones.

METHODS

Proliferation was assessed by 3H-thymidine incorporation. Cytokine generation was assessed by reverse transcription PCR and ELISA. Messenger RNA stability was assessed in the presence of actinomycin D.

RESULTS

IFN-alpha induced a concentration-dependent inhibition of antigen-driven proliferation of TH1 and TH2 clones (median effective concentration, 150 to 200 U/mL); the sensitivity of TH1 and TH2 clones to IFN-alpha was not significantly different (P =.6). IFN-alpha induced an analogous concentration-dependent inhibition of antigen-driven IL-13 generation from TH1 and TH2 clones (median effective concentration, 100 U/mL); this effect was evident by 12 hours of culture and persisted beyond 48 hours. However, IL-4 generation from TH2 clones was insensitive to IFN-alpha at all concentrations and times tested (1 to 10,000 U/mL). A similar inhibitory effect of IFN-alpha on mitogen-driven proliferation and IL-13 generation from PBMCs was demonstrated; once again, IL-4 generation from PBMCs was insensitive to IFN-alpha. IL-13 mRNA stability was unaffected by IFN-alpha, suggesting transcriptional regulation.

CONCLUSION

IFN-alpha differentially regulates antigen-stimulated IL-4 and IL-13 generation.