儿科哮喘临床治疗的研究进展

儿童过敏性疾病包括很多种,过去几年其发病率在发达国家有所上升.这类疾病是一些有遗传倾向的儿童受环境因素而诱发,而现在对于这些环境因素仍不完全清楚.异位三合症（atopic triad）通常是指异位性皮炎、过敏性鼻炎和哮喘,患者常同时出现三种疾病的症状,并且一般由最初的异位性皮炎和食物过敏发展到过敏性鼻炎、环境过敏症和哮喘,我们将此过程称之为“遗传性过敏症进行曲”（atopic march）.     

Effect of LVAD outflow conduit insertion angle on flow through the native aorta

Background and aim: The goal of this study was to evaluate the effect of surgical anastomosis configuration of the aortic outflow conduit (AOC) from a continuous flow left ventricular assist device (LVAD) on the flow fields in the aorta using CFD simulations. The geometry of the surgical integration of the LVAD is an important factor in the flow pattern that develops both in series (aortic valve closed, all flow through LVAD) and in parallel (heart pumping in addition to LVAD).

Methods: CFD models of the AOC junctions simulate geometry as cylindrical tubes that intersect at angles ranging from 30° to 90°. Velocity fields are computed over a range of cardiac output for both series and parallel flow.

Results: Our results demonstrate that the flow patterns are significantly affected by the angle of insertion of the AOC into the native aorta, both during series and parallel flow conditions. Zones of flow recirculation and high shear stress on the aortic wall can be observed at the highest angle, gradually decreasing in size until disappearing at the lowest angle of 30°. The highest velocity and shear stress values were associated with series flow.

Conclusions: The results suggest that connecting the LVAD outflow conduit to the proximal aorta at a shallower angle produces fewer secondary flow patterns in the native cardiovascular system.     

Unequal crossing-over: a common basis of single alpha-globin genes in Asians and American blacks with hemoglobin-H disease

The alpha-globin genes of five black Americans, two Chinese, and five Filipinos with HbH disease (an alpha-thalassemia state in which there is a single functional alpha gene) were analyzed by restriction endonuclease techniques. All subjects were found to have one chromosome 16, lacking both alpha genes, and another containing a single alpha gene (--/-alpha). Restriction endonuclease patterns of the DNA obtained from all 12 subjects were identical and compatible with unequal crossing-over as the mechanism of origin of the single alpha gene in these individuals.     

Intravenous infusion for the treatment of diabetic and ischaemic non-healing pedal ulcers

Diabetic and ischaemic non-healing pedal ulcers have a tendency for chronicity and increased chances of infection, which may threaten the viability of the foot. Systemic administration of therapeutic agents may be insufficient in these cases. We have assessed the role of retrograde venous perfusion (RVP) for the treatment of nine diabetic and 10 ischaemic non-healing pedal ulcers. Agents used were soda bicarbonate, heparin, lignocaine, gentamicin and pentoxiphylline. Five of nine diabetic non-healing ulcers showed complete healing and the remaining four improved. The complete recovery in the cases of diabetic ulcer occurred in 10-24 days (mean 16 days), while ischaemic ulcers took 10-14 days for complete recovery (mean 13.6 days). There was a reduction of rest pain in all 10 patients with ischaemic disease; five patients showed complete healing of ulcers, and the other five improved significantly. In two patients, pre-gangrene changes were reversed. RVP is a useful adjunct to conservative or surgical treatment of non-healing pedal ulcers. Its main impact was in improving ischaemia and promoting healing.     

Functional and phenotypic characterization of human peripheral blood stem cell harvests: a comparative analysis of cells from consecutive collections

A considerable number of patients with malignancies who are treated with high-dose therapy and hematopoietic stem cell transplantation subsequently relapse. Analyses of peripheral blood stem cell (PBSC) harvests obtained from 49 cancer patients showed that the PBSC harvest contained precursors for antitumor effector cells. Ex vivo manipulation of these harvests to maximize the antitumor effector cell activity may provide a new therapeutic approach to decrease or eliminate any minimal residual disease that remains after high-dose therapy. Characterization of PBSC from consecutive collections determined the collections best suited for ex vivo augmentation of antitumor cytotoxic effector cells. We report the results of a functional and phenotypical characterization of PBSC obtained from six consecutive collections from 18 cancer patients receiving granulocyte-macrophage colony-stimulating factor (GM- CSF) for hematopoietic stem/progenitor cell mobilization. The PBSC were evaluated for their cytotoxicity using the 51Cr-release assay. The frequency and subsets of lymphocytes were determined using flow cytometry with appropriate specific marker antibodies and differential cell counts. The content of hematopoietic progenitor cells in each collection was determined using a colony-forming unit granulocyte- macrophage (CFU-GM) culture assay. The frequency of cytotoxic effector cells including lymphokine-activated killer (LAK) cell precursors and lymphocytes was significantly greater (P < .05) in the early collections, whereas the later collections contained significantly (P < .05) more CFU-GM progenitor cells and fewer cytotoxic effector cells. Thus, our results show that PBSC obtained from advanced cancer patients do contain considerable levels of precursor cells for the generation of LAK cell populations. These results suggest that cells from the earlier collections are best suited for ex vivo manipulation to augment the antitumor effects.     

Percutaneous injury, blood exposure, and adherence to standard precautions: are hospital-based health care providers still at risk?

To examine factors associated with blood exposure and percutaneous injury among health care workers, we assessed occupational risk factors, compliance with standard precautions, frequency of exposure, and reporting in a stratified random sample of 5123 physicians, nurses, and medical technologists working in Iowa community hospitals. Of these, 3223 (63%) participated. Mean rates of hand washing (32%-54%), avoiding needle recapping (29%-70%), and underreporting sharps injuries (22%-62%; overall, 32%) varied by occupation (P<.01). Logistic regression was used to estimate the adjusted odds of percutaneous injury (aOR(injury)), which increased 2%-3% for each sharp handled in a typical week. The overall aOR(injury) for never recapping needles was 0.74 (95% CI, 0.60-0.91). Any recent blood contact, a measure of consistent use of barrier precautions, had an overall aOR(injury) of 1.57 (95% CI, 1.32-1.86); among physicians, the aOR(injury) was 2.18 (95% CI, 1.34-3.54). Adherence to standard precautions was found to be suboptimal. Underreporting was found to be common. Percutaneous injury and mucocutaneous blood exposure are related to frequency of sharps handling and inversely related to routine standard-precaution compliance. New strategies for preventing exposures, training, and monitoring adherence are needed.     

Surgical treatment for scoliosis extending to main thoracic spine by keyvertebral-screws technique （KVST）

Objective ：To introduce a key-vertebral-screws technique （KVST） in the surgical treatment of scoliosis extending to main thoracic levels, and to find the role of fulcrum bending in predicting the result of surgical treatment for scoliosis by this technique. Methods： Seventeen consecutive patients with scoliosis extending to main thoracic spine, who underwent pure posterior fusion without anterior or posterior release by KVST between January 2004 and July 2005 were evaluated for fulcrum bending flexibility, surgical correction rate, fulcrum bending correction index （FBCI） in main thoracic curves. Universal Spine System （USS） instrumentation was used in 15 cases, Monarch in another 2 cases. The severity of the curves was measured by Cobb＇s method using RadWork 6.0 software. Preoperative standing AP radiographs, preoperative fulcrum bending anterioposterior （AP） radiographs, postoperative standing AP radiographs, and most recent follow-up standing AP radiographs for spine were measured and recorded. All the data were analyzed with two-sample paired t-test by Origin 7.0 software. Results： Infection and neurological complications were not noted. No major complications were found. Just one case had some axial back pain, which got a full recovery from physiotherapy for 2 weeks. In the X-ray, there was an average correction of 71.5 % of the fused main thoracic curves, which had no significant lose of correction in final follow-up. For the whole fused main thoracic curves, the fulcrum bending flexibility were lower to operation correction rate （P=0. 013）. The average FBCI was 123%. From the data, the more rigid curves （especially fulcrum bending flexibility 〈50%）, the more correction rate operation could get, compared with fulcrum bending flexibility. Conclusion： （1） KVST is a good method in the surgical treatment of thoracic scoliosis, which can get satisfying result with lower medical cost. （2） Fulcrum bending flexibility is lower than operative correction rate by KVST in main