Serial lung scintigraphy: utility in diagnosis of pulmonary embolism

Pairs of sequential perfusion lung scans and pulmonary angiograms obtained in 45 patients were reviewed to investigate the utility of short-term, sequential scintigraphy in the diagnosis of pulmonary embolism (PE). Forty-six sequential scan pairs were reviewed; 13 were ventilation-perfusion (V-P) pairs. Angiograms were obtained within 48 hours of either the first (65%) or second (35%) perfusion scan in each pair. Sequential scintigraphic patterns were classified as showing change (i.e., improvement in defects, new defects), no change, or as being indeterminate. A changing perfusion pattern was associated with a high (20/23) likelihood of PE, but seven of 16 patients with stable perfusion patterns also had PE. The sensitivity of a changing perfusion pattern for PE was 0.74 (20/27) and its specificity was 0.75 (9/12). In two of six patients who had serial V-P studies that showed changing perfusion defects, there were matched changes in regional ventilation and angiograms were negative. The findings suggest that short-term serial perfusion lung scanning may aid the scintigraphic diagnosis of PE in certain circumstances. Serial V-P imaging is needed, however, to maximize diagnostic specificity.     

燃煤烟道蜂窝净化剂除氟效果的研究

针对中国燃煤污染氟中毒分布范围广病情严重的特点，在民用炉灶烟道内装入蜂窝状净化剂除氟措施的可行性进行了初步的探讨。其中对蜂窝状净化剂的材料配比、孔径大小、长度、吸附容量、安装方法的堵塞问题进行了较详细的实验。在现场进行了除氟效果的验证、实验结果表明，烟道内装入蜂窝状净化剂除氟效率为８９．１％，同时对煤烟中的ＳＯ２也有一定的去除效果，除硫率为５３．６％。此项措施与改炉改灶措施结合推广运用，将有助于燃煤氟硫污染问题的解决。     

Inhibition of proliferation and induction of apoptosis in juvenile myelomonocytic leukemic cells by the granulocyte-macrophage colony- stimulating factor analogue E21R

Juvenile myelomonocytic leukemia (JMML) is a malignancy that almost inevitably leads to death before adulthood. Chemotherapy has given disappointing results and a substantial number of patients relapse after bone marrow transplantation. A salient feature of this disease is that the JMML cells produce granulocyte-macrophage colony-stimulating factor (GM-CSF) spontaneously and survive and proliferate without exogeneous GM-CSF. Furthermore, JMML cells are hypersensitive to GM-CSF with addition of this cytokine leading to enhanced proliferation. We have recently generated a human GM-CSF analogue, E21R, that acts as a complete and selective GM-CSF receptor antagonist. We have now tested this molecule as a potential new agent to control the leukemic cell load in JMML with particular emphasis on its role in JMML cell survival. We found that E21R inhibited the spontaneous growth of JMML cells in vitro and caused their apoptosis in a dose- and time-dependent manner in seven of seven cases. In contrast, neither a neutralizing anti-GM-CSF monoclonal antibody (MoAb) nor a selective interleukin-1 (IL-1) receptor antagonist affected JMML cell survival. Furthermore, the apoptotic effect of E21R was seen even in the presence of interleukin-1 beta and tumor necrosis factor-alpha, which have also been implicated in the pathogenesis of JMML. The inhibitory effects of E21R on JMML cell growth and viability offer a novel approach to therapy in this lethal childhood leukemia.     

The role of endothelium in factor Xa regulation: the effect of plasma proteinase inhibitors and hirudin

The role of endothelium in the inhibition of human factor Xa was studied in a plasma environment. Human factor Xa can bind to and function on bovine aortic endothelium in a manner similar to that of bovine factor Xa. Approximately 70% of the bound factor Xa is subject to inhibition by plasma proteinase inhibitors, and the remaining 30% is irreversibly bound as part of a 125 Kd membrane-associated complex not subject to proteolytic degradation. The proportion reversibly bound and its rate of release do not alter with changes in calcium, citrate, heparin, or active proteinase inhibitor concentrations. The principal plasma proteinase inhibitor of human factor Xa was antithrombin III, which accounted for 60% to 65% of factor Xa released from endothelium, with alpha 1-proteinase inhibitor inactivating 20% to 25% and alpha 2- macroglobulin approximately 15%. All of the reversibly bound factor Xa was identified in complex with one of these three proteinase inhibitors. The thrombin active-site inhibitor hirudin was found to markedly accelerate the displacement of reversibly bound factor Xa from the endothelium and to associate specifically with factor Xa without a loss of activity toward chromogenic substrates, perhaps accounting for a novel mechanism of anticoagulation.     

Immunization with influenza A NP-expressing vaccinia virus recombinant protects mice against experimental infection with human and avian influenza viruses

Summary. Two-fold immunization of Balb/c mice with a vaccinia virus recombinant expressing the NP protein of influenza A/PR8/34 (H1N1) virus under the control of a strong synthetic promoter induced specific antibodies and protected animals against low-dose challenge by mouse-adapted heterosubtypic variants of human A/Aichi2/68 (H3N2) and avian A/Mallard/Pennsylvania/10218/84 (H5N2) influenza virus strains. The surviving immunized animals had lower anti-hemagglutinin antibody titers compared to non-immunized mice. There was no difference in viral titers in lungs of immunized and non-immunized animals that succumbed to the infection. In order to try to increase immune system presentation of NP-protein-derived peptides, and thereby increase their immunogenicity, we constructed another vaccinia-based NP-expressing recombinant containing a rapid proteolysis signal covalently bound to the NP protein. This sequence, derived from the mouse ornithine decarboxylase gene has been shown to increase degradation of various proteins. However, we found that when used as part of a recombinant NP, this signal neither increased its proteolytic degradation, nor was it more efficient in the induction of a protective response against influenza infection.     

Localization of Left Atrial Ganglionated Plexi in Patients with Atrial Fibrillation

Background. The intrinsic cardiac autonomic nervous system (ICANS), which forms a neural network, has been shown to be a critical element responsible for the initiation and maintenance of atrial fibrillation (AF). We developed a technique to localize and ablate the ganglionated plexi (GP), which serves as the "integration centers" of the ICANS.
Method. The four major atrial GP are localized by delivering high frequency stimulation (HFS; 20 Hz, 10–150 V, 1–10 ms pulse width) to atrial tissue where GP are presumed to be located. Sites showing a parasympathetic response, which is arbitrarily defined as ≥50% increase in mean R-R interval during AF, was assigned as a GP site. Radiofrequency current is then applied to that site to eliminate the parasympathetic response. All patients received ablation of the four major atrial GP, followed by pulmonary vein antrum ablation.
Results. Our preliminary results showed that all the four major atrial GP can be identified in the vast majority of patients. The parasympathetic response can be eliminated by applying radiofrequency current. In the first 83 patients, the percent of patients free of symptomatic AF or atrial tachycardia after a single ablation procedure was 80% at 12 months and 86% at a mean follow-up of 22 months.
Conclusion. These results indicate additional benefits of GP ablation to PV antrum ablation and improvement with time, particularly ≥ 12 months after ablation. We postulate that this late benefit may result from destruction of the autonomic neurons in the GP that cannot regenerate.     

Diabetes mellitus in Danish cystic fibrosis patients: prevalence and late diabetic complications

Lanng S, Thorsteinsson B, Lund-Andersen C, Nerup J, Schiatz PO, Koch C. Diabetes mellitus in Danish cystic fibrosis patients: prevalence and late diabetic complications. Acta Pzdiatr 1994;83: 72–7. Stockholm. ISSN 0803–5253.
The prevalences of impaired glucose tolerance (IGT), diabetes mellitus and late diabetic complications were studied in all Danish cystic fibrosis (CF) patients. A total of 311 CF patients were identified with an estimated ascertainment rate above 98%. Glucose tolerdnce was classified in 278 (89%) patients: the prevalences of IGT and diabetes mellitus were 13.7% (38 patients) and 14.7% (41 patients), respectively, with no sex differences. The prevalence of diabetes mellitus increased with age but not with the severity of CF as compared with age- and sex-matched non-diabetic CF patients. Diabetes was diagnosed at a median age of 20 years (range 3–40 years) and the duration of diabetes was 1.7 years (0.1–17 years). Twenty-eight of the diabetic patients (70%) were trcated with insulin, on average 20 (4–90) IU per day. Late diabetic complications were identified in 4 patients (10%) with a duration of diabetes mellitus of 1–17 years: background retinopathy (2 patients), diabetic nephropathy (1 patient), microalbuminuria (1 patient) and neuropathy (2 patients). Thus diabetic CF patients are probably not less prone to develop late diabetic complications than patients with other types of diabetes of equally long duration and comparable glycemic control.