The Novel Electrophysiology of Complex Fractionated Atrial Electrograms: Insight from Noncontact Unipolar Electrograms

Unipolar Characteristics of CFAEs. Background: The noncontact mapping (NCM) system possesses the merit of global endocardial recording for unipolar and activation mapping. Objective: We aimed to evaluate the unipolar electrogram characteristics and activation pattern over the bipolar complex fractionated atrial electrogram (CFAE) sites during atrial fibrillation (AF). Methods: Twenty patients (age 55 ± 11 years old, 15 males) who underwent NCM and ablation of AF (paroxysmal/persistent = 13/7) were included. Both contact bipolar (32–300 Hz) and NCM virtual unipolar electrograms (0.5–300 Hz) were simultaneously recorded along with the activation pattern (total 223 sites, 11 ± 4 sites/patient). A CFAE was defined as a mean bipolar cycle length of ≤ 120 ms with an intervening isoelectric interval of more than 50 ms (Group 1A, n = 63, rapid repetitive CFAEs) or continuous fractionated activity (Group 1B, n = 59, continuous fractionated CFAEs), measured over a 7.2‐second duration. Group 2 consisted of those with a bipolar cycle length of more than 120 ms (n = 101). Results: The Group 1A CFAE sites exhibited a shorter unipolar electrogram cycle length (129 ± 11 vs 164 ± 20 ms, P < 0.001), and higher percentage of an S‐wave predominant pattern (QS or rS wave, 63 ± 13% vs 35 ± 13%, P < 0.001) than the Group 2 non‐CFAE sites. There was a linear correlation between the bipolar and unipolar cycle lengths (P < 0.001, R = 0.87). Most of the Group 1A CFAEs were located over arrhythmogenic pulmonary vein ostia or nonpulmonary vein ectopy with repetitive activations from those ectopies (62%) or the pivot points of the turning wavefronts (21%), whereas the Group 1B CFAEs exhibited a passive activation (44%) or slow conduction (31%). Conclusions: The bipolar repetitive and continuous fractionated CFAEs represented different activation patterns. The former was associated with an S wave predominant unipolar morphology which may represent an important focus for maintaining AF. (J Cardiovasc Electrophysiol, Vol. 21, pp. 640‐648, June 2010)     

Homing receptors on human and rodent lymphocytes--evidence for a conserved carbohydrate-binding specificity

Lymphocyte recirculation begins with the attachment of circulating cells to the structurally distinctive postcapillary venules of lymphoid organs termed high-endothelial venules (HEVs). In both rodents and humans, the attachment of lymphocytes to the HEVs of peripheral lymph nodes (PNs) on the one hand and gut-associated lymphoid tissues (GALTs) on the other appears to involve discrete adhesive structures on the surfaces of the interacting cells. In rodents, we previously showed that a carbohydrate-binding receptor at the lymphocyte surface participates in the attachment to the HEV of peripheral nodes. The studies reported herein document the involvement of a similar receptor in the selective attachment of human peripheral blood lymphocytes to the HEVs of PNs. We argue that the close functional relationship between the human and rodent receptors indicates that this component of the adhesive interaction has been conserved through evolution.     

The effect of lithium on growth factor production in long-term bone marrow cultures

We have previously reported that lithium chloride (LiCl) stimulates the production of granulocyte-macrophage colony-forming cells (GM-CFC), pluripotent stem cells (CFU-S), and differentiated granulocytes, macrophages and megakaryocytes in murine Dexter marrow cultures and that this effect appears to be mediated indirectly by a radioresistant adherent marrow cell. In this study we have established that exposure of murine Dexter cultures to LiCl (4 mEq/L) causes an increase of colony-forming cell megakaryocytes (CFU-meg) over 1 to 6 weeks of culture in both supernatant (188% to 611%) and stromal phases (123% to 246%). Moreover, we have shown that lithium treatment of either irradiated (1,100 rad) or unirradiated stromal cells increased production of activities stimulating formation of megakaryocyte, granulocyte, macrophage, and mixed lineage colonies and proliferation of the factor-dependent cell line, FDC-P1. This FDC-P1 stimulatory activity was completely blocked by an antibody to purified recombinant granulocyte-macrophage colony stimulating factor (rGM-CSF). The baseline or lithium-induced--stromal-derived bone marrow colony stimulating activity was partially blocked by the antibody to rGM-CSF and by an antibody to purified colony stimulating factor I (CSF-1); the two antibodies combined resulted in greater than 90% inhibition of the lithium-induced marrow stimulatory activity. In addition, radioimmunoassay (RIA) showed that although CSF-1 was detectable in supernatants of these cultures, exposure to lithium did not increase CSF-1 levels. These data indicate that Dexter stromal cells produce CSF- 1 and GM-CSF and that lithium appears to exert its stimulatory effects on in vitro myelopoiesis by inducing production of GM-CSF.     

三维电解剖系统指导房性心律失常射频导管消融的价值

目的探讨电解剖系统指导在房性心律失常射频导管消融中的作用和优势。方法对25例心房颤动（阵发性15例、持续性10例）在电解剖系统指导下进行重建左心房后行线性消融，7例持续性房性心动过速（右心房性4例、左心房性3例）在电解剖系统指导下重建左／右心房标测激动顺序后行消融。结果25例心房颤动均完成预定的线性消融，其中14例阵发性者在窦性心律下电学隔离成功，10例持续性和1例阵发性者在心房颤动时电学隔离成功。7例持续性房性心动过速均在消融过程中转为窦性心律。电解剖系统指导下平均手术时间心房颤动为220min，房性心动过速为86min；平均X线透视时间心房颤动为48min，房性心动过速为20min。所有患者手术过程中均无并发症。结论在电解剖系统指引下，环肺静脉电隔离治疗心房颤动安全有效；有助于设计房性心动过速消融径线，缩短手术时间，提高成功率。     

Factors affecting the transduction of pluripotent hematopoietic stem cells: long-term expression of a human adenosine deaminase gene in mice

An amphotropic retroviral vector, LgAL(delta Mo + PyF101) containing a human adenosine deaminase (ADA) cDNA was used to optimize procedures for the lasting genetic modification of the hematopoietic system of mice. The highest number of retrovirally infected cells in the hematopoietic tissues of long-term reconstituted mice was observed after transplantation of bone marrow (BM) cells that had been cocultured in the presence of both interleukin-1 alpha (IL-1 alpha) and IL-3. A significantly lower number was detected when IL-1 alpha was omitted from such cocultures. The yield of cells that generate spleen colony-forming cells (CFU-S) in the BM of lethally irradiated recipients (MRA-CFU-S) significantly improved on inclusion of the adherent cell fraction of cocultures in the transplant. Retroviral integration patterns in MRA-CFU-S-derived spleen colonies showed that an MRA-CFU-S can produce many CFU-S during BM regeneration. Expression of hADA was detected in the circulating white blood cells of long-term reconstituted animals, demonstrating that the LgAL(delta Mo + PyF101) vector is capable of directing the sustained expression of hADA, and in approximately 35% of the transduced MRA-CFU-S-derived spleen colonies. These results should facilitate the development of gene therapy protocols for the treatment of severe combined immunodeficiency caused by a lack of functional ADA.     

Vitamin and calcium supplement use is associated with decreased adenoma recurrence in patients with a previous history of neoplasia

INTRODUCTION: Although some have suggested that certain vitamins or calcium supplements may reduce adenoma recurrence, our own prior retrospective study found no such effects. The purpose of this case-control study was to further investigate whether regular vitamin or calcium supplement intake influenced the incidence of recurrent adenomatous polyps in patients with previous neoplasia who were undergoing follow-up colonoscopy. METHODS: This study enrolled 1,162 patients who underwent colonoscopy by one of three surgeons at Columbia-Presbyterian Medical Center in New York City between March 1993 and February 1997. Of these patients 448 (250 males) had a previous diagnosis of colorectal neoplasia (cancer, adenomas, or dysplasia). Of these, 183 (40.8 percent) had an adenoma at the index colonoscopy. Information was collected on personal and family history of colonic diseases, cigarette smoking, medication, and vitamin and micronutrient supplement usage on a questionnaire that was completed by the patients before the colonoscopy. Odds ratios were obtained by unconditional logistic regression analysis, adjusting for age and gender, and used adenoma recurrence at index colonoscopy as the outcome. RESULTS: The mean interval between colonoscopic examinations was 37 months for the recurrent adenoma group and 38 months for the nonrecurrent group of patients (P = not significant). In this case-control study we found a protective effect for the use of vitamin supplements in general (any vitamin) on the recurrence of adenomas (odds ratio, 0.41; 95 percent confidence interval, 0.27–0.61). Specifically, this protective effect was observed for the use of multivitamins (odds ratio, 0.47; 95 percent confidence interval, 0.31–0.72), vitamin E (odds ratio, 0.62; 95 percent confidence interval, 0.39–0.98), and for calcium supplementation (odds ratio, 0.51; 95 percent confidence interval, 0.27–0.96). Nonsignificant protective effects were noted for carotene/vitamin A, vitamin D, and vitamin C. CONCLUSIONS: The use of multivitamins, vitamin E, and calcium supplements were found to be associated with a lower incidence of recurrent adenomas in a population of patients with history of previous colonic neoplasia. Prospective, randomized trials are needed to better assess the impact of these agents and to determine whether the use of these supplements is associated with a protective effect against recurrent adenomas.Supported by United States Surgical Corporation, Norwalk, Connecticut.Read at the meeting of The American Society of Colon and Rectal Surgeons, San Antonio, Texas, May 2 to 7, 1998.     

Rural Emergency Medical Services: Patients, Destinations, Times, and Services

This study sought to describe the volume of use, mix of patients, origin and destination of runs, times and distances to care, and the volume of clinical services provided in a rural emergency medical services region. This study summarizes all 6,080 rural emergency ambulance trip reports filed from April through September 1991 from the 12 rural counties surrounding Augusta, GA. Rural ambulances are regularly used and are used extensively by elderly populations. The pattern of services provided suggests that while advanced care may or may not have been indicated, it was rarely provided and that rural emergency medical service programs should consider a greater reliance on basic life support teams.     

Case mix measures and diagnosis-related groups: opportunities and threats for inpatient dermatology

OBJECTIVE: The changing healthcare environment world-wide is leading to extensive use of per case payment systems based on diagnosis-related groups (DRG). The aim of this study was to examine the impact of application of different DRG systems used in the German healthcare system. METHODS: We retrospectively analysed 2334 clinical data sets of inpatients discharged from an academic dermatological inpatient unit in 2003. Data were regarded as providing high coding quality in compliance with the diagnosis and procedure classifications as well as coding standards. The application of the Australian AR-DRG version 4.1, the German G-DRG version 1.0, and the German G-DRG version 2004 was considered in detail. To evaluate more specific aspects, data were broken down into 11 groups based on the principle diagnosis. MAIN OUTCOME MEASURE: DRG cost weights and case mix index were used to compare coverage of inpatient dermatological services. Economic impacts were illustrated by case mix volumes and calculation of DRG payments. RESULTS: Case mix index results and the pending prospective revenues vary tremendously from the application of one or another of the DRG systems. The G-DRG version 2004 provides increased levels of case mix index that encourages, in particular, medical dermatology. CONCLUSIONS: The AR-DRG version 4.1 and the first German DRG version 1.0 appear to be less suitable to adequately cover inpatient dermatology. The G-DRG version 2004 has been greatly improved, probably due to proceeding calculation standards and DRG adjustments. The future of inpatient dermatology is subject to appropriate depiction of well-established treatment standards.