博卡病毒感染流行现状

1概述 在世界范围内,呼吸道感染是儿童发病率和病死率的主要原因之一。儿童下呼吸道感染已成为当前儿科发病率最高的一种疾病,而病毒是小儿下呼吸道感染的重要原因。呼吸道病毒感染病原学十分复杂,目前报道在儿童急性呼吸道感染性疾病中,病毒感染主要病原为呼吸道合胞病毒、人偏肺病毒、     

博卡病毒感染流行现状

1概述在世界范围内,呼吸道感染是儿童发病率和病死率的主要原因之一.儿童下呼吸道感染已成为当前儿科发病率最高的一种疾病,而病毒是小儿下呼吸道感染的重要原因.呼吸道病毒感染病原学十分复杂,目前报道在儿童急性呼吸道感染性疾病中,病毒感染主要病原为呼吸道合胞病毒、人偏肺病毒、冠状病毒、流感病毒A型及腺病毒等.还有一部分儿童的急性呼吸道感染,虽然认为是由病毒感染引起,但是其病原并未被阐明[1].     

呼吸道黏膜免疫及其相关疾病研究进展

呼吸道是空气进入机体的通道,时刻受到非己物质及各种微生物的刺激。呼吸道黏膜免疫系统是呼吸道抵抗外来病原体入侵的重要防线,能很好区分共生菌和致病细菌。由于对呼吸道黏膜免疫系统的了解有限,我们对哮喘、急性肺损伤、慢阻肺和感染等呼吸道疾病的免疫病理机制仍知之甚少。因此,呼吸道黏膜免疫系统的研究不但有助于呼吸道疾病的预防和治疗,而且能够为新型疫苗和药物的研发和设计提供思路。     

春季注意预防呼吸道感染

随着春天的到来,呼吸道疾病尤其是呼吸道感染性疾病也开始增多.春季很容易发生感冒、流感、急性上呼吸道感染、支气管炎和肺炎等疾病,老人和小儿更易患急性呼吸道感染性疾病,特别是流行性感冒.因此,采取预防措施是相当重要的.本文为了预防这些呼吸道疾病应该注意的问题展开了陈述.     

呼吸道感染患儿血清心肌酶变化的临床探讨

目的 探讨呼吸道感染患儿血清心肌酶的变化的临床意义.方法 收集我科2006~2009年患呼吸道感染的患儿184例,所有住院患儿入院第2天空腹抽取静脉血进行心肌酶测定.结果 呼吸道感染的患儿常伴有心肌酶增高.结论 小儿呼吸道感染特别是下呼吸道感染,常伴有心肌、肝脏损害.     

呼吸道合胞病毒研究有新发现

呼吸道合胞病毒研究有新发现蚌埠医学院附属医院儿科承担的安微省卫生厅招标科研项目“双哌达膜治疗呼吸道合胞病毒肺炎基础与临床应用研究”，最近通过了由省卫生厅组织的专家鉴定。呼吸道合胞病毒是婴幼儿最重要的下呼吸道感染病原体，可引起婴幼儿支气管炎及肺炎，日后...     

季节性流感与甲型H1N1流感

流行性感冒（流感）是由流感病毒引起的急性呼吸道传染病。流感病毒传染性强,传播速度快。主要通过呼吸道传播,接触患者的呼吸道分泌物、体液和被污染的物品也可造成传播。     

呼吸道合胞病毒的蛋白特征及抗原变异

呼吸道合胞病毒是非节段性的单链负股RNA病毒，是引起婴幼儿下呼吸道感染的重要原因。本文就近年来对呼吸道合胞病毒的蛋白特征和抗原变异的研究作一综述。     

牛呼吸道合胞病毒的免疫抑制作用

牛呼吸道合胞病毒的免疫抑制作用［英］ＷｏｌｄｅｈｉｗｅｔＺ／／ＳｃａｎｄＪＩｍｍ－ｕｎｏｌ．－１９９２，３６（１１）．－７５～８０呼吸道合胞病毒是婴幼儿呼吸道的主要病原菌，该文利用小羊为实验动物对牛呼吸道合胞病毒的免疫抑制作用进行了研究。所用病毒为牛...     

呼吸道合胞病毒的蛋白特征及抗原变异

呼吸道合胞病毒是非节段性的单链负股RNA病毒,是引起婴幼儿下呼吸道感染的重要原因.本文就近年来对呼吸道合胞病毒的蛋白特征和抗原变异的研究作一综述.     

The relationship of plasma histamine to the activity of bronchial asthma

Venous plasma histamine levels were measured in 60 asthmatic subjects in order to investigate the role of histamine in naturally occurring asthmatic episodes. The patients were divided into 3 groups of 20 according to the degree of disease activity. Group A consisted of asthmatic patients with severe exacerbations. Flow/volume curves demonstrated a forced expiratory volume in 1 sec to forced vital capacity ratio ($\text{FEV}{}_1\text{FVC}$) of less than 55% and a maximum expiratory flow at 50% of FVC (MEF₅₀) of less than 1.0 L/sec. Asthmatics in group B were in partial remission. The patients in this group had $\text{FEV}{}_1\text{FVC}$ ratios between 55% and 75% and MEF₅₀ values between 1.0 and 4.0 L/sec. The remaining asthmatic patients (group C) were in complete remission. They were asymptomatic and had normal physical examinations and flow/volume curves. Venous plasma histamine levels were also measured in 50 normal control subjects (group D). Every asthmatic subject in group A had plasma histamine above 1.25 ng/ml (mean, 1.9 ng/ml ± 0.5). Only 3 asthmatic patients in group B and 3 in group C had venous plasma histamine levels greater than 1 ng/ml. None of the normal subjects in group D had plasma histamine above 1 ng/ml. These data show a relationship between spontaneously occurring asthmatic attacks and elevated plasma histamine and support previous studies suggesting that histamine may play a role in the mediation of bronchial asthma.     

Exercise and isocapnic hyperventilation-induced bronchoconstriction in asthma: relevance of circulating basophils to measurements of plasma histamine

The relationship of airway cooling during exercise to changes in airway caliber, plasma histamine levels, and circulating basophils was investigated in eight allergic asthmatic and eight normal subjects. In asthma matched RHE during exercise and ICH produced almost identical bronchoconstriction with maximum falls in SGaw of 61.0 +/- 4.5% and 57.9 +/- 5.2%, respectively. A similar RHE in normal subjects was associated with a 7.9 +/- 3.3% fall in SGaw. The resting plasma-histamine levels were higher in the asthmatic (0.52 +/- 0.06 ng/ml) than in the normal (0.31 +/- 0.07 ng/ml, p less than 0.05) subjects. No significant change in plasma histamine occurred after exercise in either group nor in the asthmatic subjects with ICH. In contrast, exercise but not ICH stimulated an increase in leukocytes, basophils, and total blood histamine in parallel with the airway response that reached a maximum at 2 to 5 min in both normal and asthmatic subjects. There was a positive correlation between basal plasma and total blood-histamine levels (r = 0.67, p less than 0.01) in normal and asthmatic subjects suggesting that basophils contribute significantly to plasma histamine. The spontaneous basophil release of histamine was greater in asthmatic (13.4 +/- 2%) than in normal subjects (6.46 +/- 7%, p less than 0.005), which is consistent with the higher resting plasma-histamine levels in the asthmatic subjects. These findings suggest that plasma-histamine changes with exercise in asthma but not ICH may be related to the associated basophilia and sample handling rather than intrapulmonary mast cell degranulation.     

Relationship between LTC4 generation of hypodense eosinophils and bronchial hyperreactivity in asthmatic children

In 19 asthmatic children aged 6-16 years, the degree of bronchial hyperreactivity was determined in relationship to the concentration of inhaled histamine which caused a fall of the specific conductance (sGaw) to 60% of the baseline value PC60sGaw. At the time of lung function testing, a sample of heparinized blood was obtained from each patient. Eosinophils were purified and separated into a normodense and hypodense fraction by Percoll gradient centrifugation. After in vitro stimulation by ionophore A 23187, the leukotriene C4 (LTC4) content was determined in the culture supernatants. Hypodense eosinophils of the 13 children with a histamine threshold lower than 1 mg/ml generated significantly (p less than 0.01) larger amounts of LTC4 (0.8-36.3 ng/10(6) cells) when compared to 6 children with a histamine threshold higher than 1 mg/ml (0.7-12.1 ng/10(6) cells) and 12 healthy controls (0.4-8.2 ng/10(6) cells). Preincubation of eosinophils with platelet activating factor (PAF) induced an enhanced LTC4 production, not only in hypodense cells from both asthmatic groups but also in normodense cells from patients with severe hyperresponsiveness. These results are consistent with other results which suggest an important role of eosinophils, their activation by PAF and enhanced release of spasmogenic LTC4 in the pathogenesis of asthma.     

Plasma histamine and bronchial reactivity in allergic asthma

Histamine is an important mediator of allergic inflammation and bronchial hyperresponsiveness (BHR), a hallmark of asthma. Studies on the relationship between plasma histamine and BHR in allergic asthmatic patients have yielded controversial results. We therefore measured plasma histamine and bronchial reactivity in 30 nonsmoker volunteers taking no medication. Eleven were normal subjects; 19 were stable, mildly allergic asthmatic patients. Venous blood was taken to measure blood cells and basal plasma histamine by radioimmunoassay. After blood sampling, all subjects underwent a measurement of PC₂₀M (concentration of methacholine causing a 20% fall in FEV₁). Mean plasma histamine levels were 0.21 ± 0.1 ng/ml and 0.44 ± 0.3 ng/ml in normal and asthmatic subjects, respectively (P<0.05). We found a significant increase of blood eosinophils and basophils in asthmatic patients, and a positive correlation between plasma histamine and circulating basophils. PC₂₀M was greater than 16 mg in normal volunteers, and mean PC₂₀M was 2.1 ± 2 mg/ml in asthmatic patients. PC₂₀M did not correlate with plasma histamine levels, but it did so negatively with blood eosinophils. The increased plasma histamine concentration in mildly atopic asthmatic patients might be a consequence of the high basophil releasability of atopies and the higher basophil counts in allergic asthma. Plasma histamine is thus unlikely to be a determinant of BHR in asthma.     

Measurement of urinary histamine: comparison of fluorometric and radioisotopic-enzymatic assay procedures

Assessment of urinary histamine may prove useful in determining the role of histamine in human health and disease. Urinary histamine may be accurately estimated by a modified fluorometric assay employing diamine oxidase (DAO) digestion and cation-exchange chromatography. Normal urine histamine values obtained by this assay are: arithmetic means (+/- SEM), 8.6 +/- 0.6 ng/ml and 10.5 +/- 0.7 micrograms/24 hr; geometric means (+/- SEM), 6.2 +/- 1.1 ng/ml and 10.0 +/- 1.3 micrograms/24 hr. However, the radioisotopic-enzymatic assay is less expensive, easier to perform, and possibly more sensitive. Therefore the two procedures were compared. The radioenzyme assay was found to be affected by factors in urine (possibly salt concentrations) requiring extraction of histamine from urine by butanol-heptane. Moreover, it was found to be necessary to compare DAO-digested samples with undigested samples to accurately estimate histamine levels and to run the standard curve of histamine in DAO-digested urine. Even with these modifications, the radioenzyme assay was not as accurate as the fluorometric assay for urine samples having histamine values about 60 ng/ml. Therefore we recommend utilization of the modified fluorometric assay for the measurement of urinary histamine levels.     

Comparison of methodologies to measure human lung histamine.

The measurement of histamine in samples obtained from human lung is important in determining the roles of histamine and mast cells in normal and disease states. We, therefore, compared different assays for the measurement of histamine in human lung samples. Both a single isotope enzymatic assay and a radioimmunoassay (RIA) were capable of accurately measuring the low concentrations of histamine (0.05-2.0 ng/ml) normally found in bronchoalveolar lavage fluid. The RIA was also able to measure histamine levels up to 1500 ng/ml in human lung tissue samples. Moreover, the RIA measurement of high levels of histamine in lung samples compared favorably to an automated spectrofluorometric method. Unlike either the single isotope enzymatic assay or the automated spectrofluorometric assay which have effective capabilities at less than and greater than 2 ng/ml, respectively, the RIA can accurately measure histamine levels from 0.05 to 1500 ng/ml. Since the RIA is easier to perform, less costly, and has a wider range of effectiveness, this assay should prove valuable in assessing histamine levels from a variety of human lung samples, thereby, providing an avenue to elucidate the roles of histamine and mast cells in lung functions.     

Comparison of four different measures of bronchial responsiveness in asthmatic children

Although several tests are available to assess the presence and severity of bronchial hyperresponsiveness (BHR), there is no agreement on the most appropriate stimulus. The most commonly used stimuli are methacholine, histamine, and exercise. Daily peak expiratory flow (PEF) variation has been reported to correlate with the severity of BHR, and in recent years this has been widely used because of its noninvasiveness and ease of performance. This study was carried out to determine the relationship among these four commonly used measures of bronchial responsiveness in asthmatic children. For this purpose, 12 asthmatic children of varying disease severity were recruited. Subjects underwent three challenges on 3 separate days in 1 week. During the week preceding the challenges (methacholine, histamine, and exercise), patients recorded PEF three times a day. All patients had PC₂₀ less than 8 mg/ml with methacholine and histamine. Patients with PC₂₀ greater than 3.5 mg/ml for both methacholine or histamine had negative exercise challenges. The strongest correlation was between histamine and methacholine ( r =0.95). Exercise-induced bronchospasm had substantial and significant correlation with the other three measures. No significant correlation was observed between PEF variability and histamine or methacholine. The varying degrees of relationships among the four commonly used measures suggests that each method yields information on different but related phenomena. More than one measure may be required to detect the different aspects of asthmatic bronchial responsiveness.     

Effects of infused histamine: correlation of plasma histamine levels and symptoms

Plasma and urine histamine levels were measured during sequential infusions of histamine (0.05, 0.1, 0.25, 0.5, and 1.0 microgram/kg/min histamine base for 30 min each) to determine the plasma level required to elicit flushing, headaches, tachycardia, and diastolic hypotension. Each study was performed with subjects on no medications or after pretreatment with hydroxyzine and/or cimetidine in order to confirm the receptor subtype involved in each of the responses. Resting plasma histamine levels were 0.62 +/- 0.12 ng/ml, and levels rose progressively indirect proportion to the concentration of infused histamine. Plasma levels of histamine required to elicit symptoms were as follows: 1.61 +/- 0.30 ng/ml = 30% increase in heart rate, 2.39 +/- 0.52 ng/ml = significant flush and headache, and 2.45 +/- 0.13 ng/ml = 30% increase in pulse pressure. Cimetidine pretreatment failed to influence the histamine level required to elicit symptoms, hydroxyzine pretreatment significantly raised the level required to increase heart rat by 30%, and the combination of antihistamines significantly raised the threshold for histamine to elicit all the response. Urine histamine was increased in direct proportion to the histamine infusions, and because of stability, accessibility, and the capacity for retrospective diagnosis, urine is the suggested fluid to employ to measure histamine release in humans.     

Enzyme-linked immunosorbent assay for detection of respiratory syncytial virus infection: development and description

An indirect enzyme-linked immunosorbent assay for detection of respiratory syncytial virus (RSV) antigens was developed, using commercially available antisera. Horse anti-RSV and calf antiserum to bovine RSV were used as capture and detector antibodies, respectively. The assay could detect as few as 50 PFU of unpurified RSV per ml in infected cell culture supernatant fluids and as little as 10 ng of affinity-purified RSV antigen per ml. No cross-reactions were observed with heterologous virus types. Freeze-thaw treatment had no effect on RSV enzyme-linked immunosorbent assay titers, but viral transport medium inhibited RSV enzyme-linked immunosorbent assay titers from 10- to 100-fold. The assay can be easily performed in 24 h and is a sensitive and specific method for the detection of RSV antigens.     

Measurement of urinary histamine: Development of methodology and normal values

A small portion of the histamine that circulates through the kidney is excreted intact. Thus, the measurement of histamine in urine may be employed to monitor fluctuations in plasma histamine and has several advantages: stability, accessibility, and the opportunity for retrospective analysis. A method for measuring urine histamine was developed based on cation-exchange chromatography, organic solvent extraction, o-phthalaldehyde condensation, and measurement of fluorescence. However, because the histamine measured by this procedure was higher than that measured by other techniques, a portion of each sample was digested with diamine oxidase and the difference between the two portions of each sample, after isolation and fluorescent assay, was taken to reflect histamine. Normal urinary histamine levels of 13 ± 8 ng/ml, 14 ± 9 μg/24 hr, or 14 ± 72 ng/mg creatinine/ml were found. Male and female subjects excreted equivalent concentrations; spot, short-timed, or 24-hr collections provided equivalent results; and histamine in frozen urine was stable ?6 mo. Two patients with systemic mastocytosis and two with idiopathic anaphylaxis had elevated urine histamine levels. Monitoring urine histamine may be useful in assessment of conditions in which histamine plays a role.