Respiratory exposure to diesel exhaust particles decreases the spleen IgM response to a T cell-dependent antigen in female B6C3F1 mice.

We investigated the systemic immunotoxic potential of respiratory exposure to diesel exhaust particles (DEP) in this study. Female B6C3F1 mice (approximately 8 weeks old) were exposed to increasing concentrations of DEP intratracheally, 3 times every two weeks, and sacrificed 2 or 4 weeks after the first exposure. The systemic toxicity and immune status in mice were evaluated. Mice exposed to DEP (1 to 15 mg/kg) showed no significant changes in body, spleen, or liver weights. Lung weights were increased in the mice exposed to 15 mg/kg DEP for 2 or 4 weeks. Except for a decreased platelet count, no significant alterations occurred in hematological parameters following DEP exposure. The number of splenic anti-sheep red blood cell (sRBC) IgM antibody-forming cells (AFC) decreased following DEP exposure for 2 weeks. This effect was less severe following 4 weeks of exposure and was only evident in the high dose group. Exposure to DEP also resulted in a significant decrease in the absolute numbers and the percentages of total spleen cells for total, CD4(+), and CD8(+) T cells, while the numbers of B cells and total nucleated cells in spleen were not significantly changed. The proliferative response of splenocytes to the T-cell mitogen, concanavalin A (ConA), as well as their production of IL-2 and IFN-gamma, was decreased dose-dependently following exposure of mice to DEP for 2 weeks, whereas proliferation was not changed in response to anti-CD3 monoclonal antibody. In summary, short-term respiratory exposure of mice to DEP resulted in systemic immunosuppression with evidence of T cell-mediated and possibly macrophage-mediated mechanisms.     

Variation of Nasal Respiratory Pattern With Age During Growth and Development

The purpose of this study was to determine changes in nasal respiratory pattern with growth and development, particularly to determine the age where upper airway growth ceases. The results on 361 healthy subjects, aged 7 to 24 years, based on aerodynamic measurements during rest breathing, showed clear differences between inspiratory and expiratory phases. Nasal airflow rate and cross-sectional area increased and oral-nasal pressure and nasal resistance decreased with age up to the age of 16, levelling by the age of 20 years. The body size and gender had effect only on nasal airflow rate. This study suggests that the measurements of the nasal respiratory pattern, determining impaired nasal airway, should be done during inspiration and using age-related assesment from a healthy population until the age of 16 years. From then on, guidelines for adults are applicable.     

High frequency oscillatory ventilation in infants with increased intra-abdominal pressure

AIMS—To describe the short term effect of high frequency oscillatory ventilation on infants with severe abdominal distension who could not be conventionally ventilated.METHODS—Eight infants (25 to 38 gestational weeks, birthweight 600-3200 g, postnatal age 1 to 190 days) with a variety of intra-abdominal pathologies, resulting in severe abdominal distension and failure of conventional ventilation, were studied.RESULTS—The oxygenation status of all infants significantly improved within an hour of changing from conventional to high frequency oscillatory ventilation. Infants who were hypercapneic on conventional ventilation also showed a reduction in PaCO₂. As a group, the mean (SD) PaO₂/FIO₂ improved from 4.99 (0.98) kpa to 11.55 (3.8) kpa (P = 0.002), and the PaCO₂ from 6.48 (2.12) kpa to 4.89 (1.22) kpa (P= 0.028). These improvements were sustained throughout the next 48 hours.CONCLUSION—High frequency oscillatory ventilation seems to be an effective rescue measure for infants with respiratory failure secondary to increased intra-abdominal pressure.     

Randomised controlled double blind study of role of recombinant erythropoietin in the prevention of chronic lung disease

AIM—To evaluate the role of recombinant human erythropoietin (R-HuEpo) in reducing iron infusion, which may exacerbate free radical damage, leading to chronic lung disease.METHODS—A multicentre, randomised, placebo controlled, double blind study was carried out in four neonatal intensive care units in Yorkshire. Infants were randomly allocated and received either R-HuEpo (480 U/kg/wk) or placebo by twice weekly subcutaneous injection. The primary outcome measure was the number of days on respiratory support and a secondary outcome the number of blood transfusions required.RESULTS—Forty two very low birthweight (VLBW) infants were randomly allocated. There was little difference in the need for respiratory support one month after randomisation, but subsequently there was a trend towards a reduction in the proportion requiring respiratory support in the R-HuEpo group (difference at three months ?0.50, 95% confidence interval ?1.00, 0.17). During stay in hospital, the median number of blood transfusions was lower for infants in the R-HuEpo group (difference in medians ?2, 95% CI ?4, 0). The study was stopped early because of failure to recruit babies at the expected rate.CONCLUSIONS—R-HuEpo seems to reduce the number of days in oxygen for ill VLBW infants. These data could be used to construct a larger multicentre study to evaluate this effect further.     

Diagnosis of pneumothorax in critically ill adults

The diagnosis of pneumothorax is established from the patients' history, physical examination and, where possible, by radiological investigations. Adult respiratory distress syndrome, pneumonia, and trauma are important predictors of pneumothorax, as are various practical procedures including mechanical ventilation, central line insertion, and surgical procedures in the thorax, head, and neck and abdomen. Examination should include an inspection of the ventilator observations and chest drainage systems as well as the patient's cardiovascular and respiratory systems.Radiological diagnosis is normally confined to plain frontal radiographs in the critically ill patient, although lateral images and computed tomography are also important. Situations are described where an abnormal lucency or an apparent lung edge may be confused with a pneumothorax. These may arise from outside the thoracic cavity or from lung abnormalities or abdominal viscera inside the chest.     

Outcome of children with respiratory symptoms without objective evidence of asthma: a two-year, prospective, follow-up study

This study evaluated the outcome of 33 children with asthma-like symptoms without objective evidence of asthma, and the role of certain factors in predicting the development of clinical asthma in these children. Data on symptom histories, lung functions (flow-volume spirometry, free running test and methacholine inhalation challenge test) and atopic sensitization (skin prick tests and markers of eosinophilic inflammation) were collected twice with an interval of 2 y, and the diagnoses were re-evaluated after the follow-up period. Based on the results, it was concluded that one-third of the children with prolonged or recurrent lower airway symptoms, such as cough or wheeze, either have mild asthma or will develop asthma in the near future. Children who had a significant response [≥ 10% fall in forced expiratory volume in 1 s (FEV1)] in the free running test formed a risk group for active asthma, whereas other baseline characteristics seemed not to predict the outcome.     

Differential patterns of circulating adhesion molecules in children with bronchial asthma and acute bronchiolitis

The object of the study was to assess the levels of circulating forms of the cellular adhesion molecules ICAM-I, VCAM-1, E-selectin, L-selectin and P-selectin in young children with asthma and acute bronchiolitis. Thirty-nine children aged 12 to 84 months with mild or moderate asthma were studied at admission for acute asthma (n = 15) or in a stable phase (n = 24). Ten of the children with acute asthma were seen again after one month. Twenty-two children aged 1 to 17 months with acute bronchiolitis and nine non-atopic controls were also included in the study. In children with acute asthma, the mean concentration of circulating soluble ICAM-1 (SICAM-I) was increased compared to children with stable asthma (mean 442 μg/l versus 363 μg/l; p < 0.001) and to controls (363 μg/l; p < 0.05). The levels of SICAM-1 remained high at follow up. In children with stable asthma, the mean serum concentration of soluble L-selectin (sL-selectin) (2080 μg/l) was significantly higher than in the controls (1664 μg/l; p < 0.05). The levels of circulating cellular adhesion molecules were similar in atopic and non-atopic asthmatics. Children with acute bronchiolitis had increased serum levels of soluble VCAM-1 (sVCAM-I) (1637 μg/l versus 1019 μg/l in the controls; p < 0.01) and sL-selectin (2041 μg/l versus 1664 μg/l in the controls; p < 0.05). There was no difference between the levels of circulating cellular adhesion molecules in children with respiratory syncytial virus (RSV) positive and RSV negative bronchiolitis. Soluble E-selectin (sE-se-lectin) and soluble P-selectin (sP-selectin) in serum were not significantly increased in any of the groups studied. In conclusion, our data suggest differential patterns of circulating cellular adhesion molecules in young children with acute asthma, stable asthma, and acute bronchiolitis, which may reflect differences in the underlying inflammatory processes in these obstructive pulmonary diseases.     

Ureaplasma urealyticum, erythromycin and respiratory morbidity in high-risk preterm neonates

We investigated colonization with Ureaplasma urealyticum (Uu) in infants <30 weeks gestation and assessed the relationship to other risk factors influencing respiratory morbidity, plus the effect of treatment with erythromycin. Ventilated preterm infants [ n = 155; median GA 26 (23–29) weeks] were cultured for Uu in endotracheal aspirate and nasopharynx. Colonized infants were randomly assigned to treatment with erythromycin 40mg/kg/d, intravenously or orally. The rate of colonization was 29/155 (19%) and the Uu-colonized infants had lower mean gestational ages than the culture-negative infants (25 vs 26 weeks). For the colonized infants PROM (48% vs12%), chorioamnionitis in the mother (46% vs 17%) and vaginal delivery (71% vs 29%) were more common. More colonized infants needed supplemental oxygen at 36 weeks'postconceptual age ( p < 0:05). Erythromycin treatment was effective in reducing colonization with negative control cultures in 12/14 (86%) of treated infants. No significant differences were found between the colonized treated infants ( n = 14) and those not treated ( n = 14) in time with supplemental oxygen. Oxygen requirement at 36 weeks was related to lower gestational age, late appearance of PDA, late onset sepsis and signs of chorioamnionitis in the mother. We conclude that the Uu colonization is related to increasing immaturity, the presence of prolonged rupture of membranes, signs of chorioamnionitis and vaginal delivery. Treatment with erythromycin reduced colonization but did not significantly alter length of time with supplemental oxygen.     

柴莪退热栓治疗急性病毒性上呼吸道感染临床研究

目的观察柴莪退热栓治疗急性病毒性上呼吸道感染中医辨证属卫分证、卫气同病证的临床疗效,并探讨外感高热卫分证、卫气同病证证候与疗效间的关系.方法将患者 80例随机分为治疗组与对照组,分别予柴莪退热栓和消炎痛栓塞肛,并进行安全性评价.结果两组总体疗效相当,且未发现明显毒副作用.结论 柴莪退热栓治疗急性病毒性上呼吸道感染疗效满意.     

公共卫生危机管理探讨

本文以社会学、心理学的相关原理为理论基点 ,论述了危机、卫生危机及公共卫生危机的概念、因素和影响 ,探讨了政府在公共卫生危机管理中应对策略 ,以资政府相关组织借鉴。