The effect of skeletal muscle mass on dose-limiting toxicities during (chemo)radiotherapy in patients with head and neck cancer: A systematic review and meta-analysis.

Radiotherapy (RT) is a standard treatment for head and neck cancer (HNC) and chemoradiotherapy (CRT) is indicated for patients with locally advanced disease. Toxicities during treatment are common and can lead to early cessation of chemotherapy and radiotherapy (RT) interruptions, which can affect oncologic outcomes. Skeletal muscle mass (SMM) is a new biomarker to predict toxicities and overall survival. The aim of this systematic review is to provide an overview of studies towards the associations between SMM and dose limiting toxicity (DLT) and/or RT interruptions in HNC patients. A systematic literature search was conducted and yielded 270 studies. Inclusion criteria were articles published in English that investigated the effect of low SMM measured in humans with HNC on toxicities during CRT or RT. Studies that did not investigate oral cavity, oropharynx, larynx, hypopharynx, nasopharynx cancers or carcinoma of unknown primary were excluded. This led to the inclusion of 22 original studies. The prevalence of low SMM ranged from 19.7 % to 74.7 %. SMM was often assessed by measuring the cross-sectional muscle area at the level of the third cervical vertebra on computed tomography scans. Cut-off values used to categorize patients in SMM groups varied. In the meta-analyses heterogeneity was moderate (I2 = 68 % and 50 % respectively). Patients with low SMM had higher, but only borderline significant, odds of DLT during CRT (OR 1.60; 95 % CI 1.00-2.58; p = 0.0512) and RT interruptions (OR 1.89; 95 % CI 1.00-3.57; p = 0.0510) compared to patients without low SMM. To conclude, in HNC patients low SMM, defined with different methods and cut-off values, is associated with DLT and RT interruptions during (C)RT, although the difference is only borderline statistically significant.

Is locally advanced head and neck cancer 'increasing' in the Netherlands? The paradox of absolute numbers, standardized incidence rates and proportional share.

BACKGROUND: Several reports have indicated that locally advanced head and neck cancer (LAHNC) has increased in the past decade. However, incidence trends cannot be easily compared because slightly different definitions of LAHNC were used. AIM: To investigate if the incidence of locally advanced disease (LAD) in the oral cavity, oropharynx, hypopharynx and larynx is indeed increasing over time, considering the growing and ageing population in the Netherlands. PATIENTS AND METHODS: Data were obtained from the Netherlands Cancer Registry (NCR). Primary head and neck squamous cell carcinomas of the oral cavity, oropharynx, hypopharynx and larynx diagnosed between 1989 and 2017 were included. Yearly numbers and European standardized incidence rates (ESRs) were reported by extent of disease. The annual percentage change (APC) over time in ESRs was calculated to assess trends. RESULTS: Absolute numbers and ESRs of LAD increased over time for oral cavity and most prominently for oropharynx carcinomas (before 1996, APC: 0.4, 95%CI: 0.1; 0.8 and APC: 5.7 (95%CI: 3.1; 8.4) after 1996: 1.5 (1.0; 2.0) respectively. For hypopharynx cancer the absolute number and ESR of LAD increased until 1997 and declined with 0.8% per year since 1997. Absolute numbers of patients with larynx cancer stayed stable over time, while ESR decreased (APC: -0.8 (95%CI: -1.1; -0.6)). CONCLUSION: The perception of an increasing trend in LAD in the Netherlands can be attributed to the increasing incidence of oral cavity and oropharynx carcinomas. For LAD of the hypopharynx a decreasing trend was observed. In larynx cancer, the proportional share of LAD of the larynx increased, even though incidence rates declined.

Determination of the Porosity of PLGA Microparticles by Tracking Their Sedimentation Velocity Using a Flow Imaging Microscope (FlowCAM).

PURPOSE: To investigate whether particle sedimentation velocity tracking using a flow imaging microscope (FlowCAM) can be used to determine microparticle porosity. METHODS: Two different methods were explored. In the first method the sedimentation rate of microparticles was tracked in suspending media with different densities. The porosity was calculated from the average apparent density of the particles derived by inter- or extrapolation to the density of a suspending medium in which the sedimentation velocity was zero. In the second method, the microparticle size and sedimentation velocity in one suspending fluid were used to calculate the density and porosity of individual particles by using the Stokes' law of sedimentation. RESULTS: Polystyrene beads of different sizes were used for the development, optimization and validation of the methods. For both methods we found porosity values that were in excellent agreement with the expected values. Both methods were applied to determine the porosity of three PLGA microparticle batches with different porosities (between about 4 and 52%). With both methods we obtained microparticle porosity values similar to those obtained by mercury intrusion porosimetry. CONCLUSIONS: We developed two methods to determine average microparticle density and porosity by sedimentation velocity tracking, using only a few milligrams of powder.

Nurses' Perceptions of Pediatric Intensive Care Unit Environment and Work Experience After Transition to Single-Patient Rooms.

BACKGROUND: The architectural design of the pediatric intensive care unit may play a major role in optimizing the environment to promote patients' sleep while improving stress levels and the work experience of critical care nurses. OBJECTIVES: To examine changes in nurses' perceptions of the environment of a pediatric critical care unit for promotion of patients' sleep and the nurses' work experience after a transition from multipatient rooms to single-patient rooms. METHODS: A cross-sectional survey of nurses was conducted before and after the move to a new hospital building in which all rooms in the pediatric critical care unit were single-patient rooms. RESULTS: Nurses reported that compared with multipatient rooms, single-patient private rooms were more conducive to patients sleeping well at night and promoted a more normal sleep-wake cycle (P < .001). Monitors/alarms and staff conversations were the biggest factors that adversely influenced the environment for sleep promotion in both settings. Nurses were less annoyed by noise in single-patient rooms (33%) than in multipatient rooms (79%; P < .001) and reported improved exposure to sunlight. CONCLUSIONS: Use of single-patient rooms rather than multipatient rooms improved nurses' perceptions of the pediatric intensive care unit environment for promoting patients' sleep and the nurses' own work experience.

Bilateral versus unilateral cochlear implantation in young children.

OBJECTIVES: To compare the preverbal communication skills of two groups of young implanted children: those with unilateral implantation and those with bilateral implantation. MATERIAL AND METHODS: The study assessed 69 children: 42 unilaterally and 27 bilaterally implanted with age at implantation less than 3 years. The preverbal skills of these children were measured before and 1 year after implantation, using Tait Video Analysis that has been found able to predict later speech outcomes in young implanted children. RESULTS: Before implantation there was no significant difference between the unilateral group and the bilateral group. There was still no difference at 12 months following implantation where vocal autonomy is concerned, but a strongly significant difference between the groups for vocal turn-taking and non-looking vocal turns, the bilateral group outperforming the unilateral group. Regarding gestural turn-taking and gestural autonomy, there was a strongly significant difference between the two groups at the 12 month interval, and also a difference before implantation for gestural autonomy, the unilateral group having the higher scores. Multiple regression of non-looking vocal turns revealed that 1 year following implantation, bilateral implantation contributed to 51% of the variance (p<0.0001), after controlling for the influence of age at implantation and length of deafness which did not reach statistical significance. CONCLUSIONS: Profoundly deaf bilaterally implanted children are significantly more likely to use vocalisation to communicate, and to use audition when interacting vocally with an adult, compared with unilaterally implanted children. These results are independent of age at implantation and length of deafness.

SP-D-dependent regulation of NO metabolism in lipopolysaccharide-stimulated peritoneal macrophages.

This work was designed to study the role of surfactant protein D in the regulation of NO synthesis by "non-alveolar" microphages. We evaluated whether the effects of surfactant protein D depend on the phenotype of macrophages. In the absence of surfactant protein D, the LPS-induced iNOS response was shown to decrease in macrophages of native and proinflammatory phenotypes by 30%, and in macrophages of the antiinflammatory phenotype (by 63%). Under the influence of lipopolysaccharide in high doses (500 ng/ml), NO(2)*- production by mouse macrophages without surfactant protein D was reduced in native cells (by 25%), but increased in proinflammatory (by 40%) and antiinflammatory phenotypes (by 12% compared to mouse macrophages with surfactant protein D). Our results suggest that surfactant protein D is involved in the immune response in the whole organism, but not only in the lungs. The effect of surfactant protein D depends on the phenotype of macrophages.

Developing and testing an intervention to prevent homelessness among individuals discharged from psychiatric wards to shelters and 'No Fixed Address'.

Shelter data in a recent study revealed discharges from psychiatric facilities to shelters or the street occurred at least 194 times in 2002 in London, Ontario, Canada. This problem must be addressed to reduce the disastrous effects of such discharge, including re-hospitalization and prolonged homelessness. An intervention was developed and tested to prevent homelessness associated with discharge directly to no fixed address. A total of 14 participants at-risk of being discharged without housing were enrolled, with half randomized into the intervention group. The intervention group was provided with immediate assistance in accessing housing and assistance in paying their first and last month's rent. The control group received usual care. Data was collected from participants prior to discharge, at 31 and 6-months post-discharge. All the individuals in the intervention group maintained housing after 3 and 6 months. All but one individual in the control group remained homeless after 3 and 6 months. The exception joined the sex trade to avoid homelessness. The results of this pilot were so dramatic that randomizing to the control group was discontinued. Discussions are underway to routinely implement the intervention. Systemic improvements can prevent homelessness for individuals being discharged from psychiatric wards.

Susceptibility to ozone-induced airway inflammation is associated with decreased levels of surfactant protein D.

BACKGROUND: Ozone (O3), a common air pollutant, induces exacerbation of asthma and chronic obstructive pulmonary disease. Pulmonary surfactant protein (SP)-D modulates immune and inflammatory responses in the lung. We have shown previously that SP-D plays a protective role in a mouse model of allergic airway inflammation. Here we studied the role and regulation of SP-D in O3-induced inflammatory changes in the lung. METHODS: To evaluate the effects of O3 exposure in mouse strains with genetically different expression levels of SP-D we exposed Balb/c, C57BL/6 and SP-D knockout mice to O3 or air. BAL cellular and cytokine content and SP-D levels were evaluated and compared between the different strains. The kinetics of SP-D production and inflammatory parameters were studied at 0, 2, 6, 12, 24, 48, and 72 hrs after O3 exposure. The effect of IL-6, an O3-inducible cytokine, on the expression of SP-D was investigated in vitro using a primary alveolar type II cell culture. RESULTS: Ozone-exposed Balb/c mice demonstrated significantly enhanced acute inflammatory changes including recruitment of inflammatory cells and release of KC and IL-12p70 when compared with age- and sex-matched C57BL/6 mice. On the other hand, C57BL/6 mice had significantly higher levels of SP-D and released more IL-10 and IL-6. Increase in SP-D production coincided with the resolution of inflammatory changes. Mice deficient in SP-D had significantly higher numbers of inflammatory cells when compared to controls supporting the notion that SP-D has an anti-inflammatory function in our model of O3 exposure. IL-6, which was highly up-regulated in O3 exposed mice, was capable of inducing the expression of SP-D in vitro in a dose dependent manner. CONCLUSION: Our data suggest that IL-6 contributes to the up-regulation of SP-D after acute O3 exposure and elevation of SP-D in the lung is associated with the resolution of inflammation. Absence or low levels of SP-D predispose to enhanced inflammatory changes following acute oxidative stress.

Determination of threshold values for determining the size of the fraction of steroid hormone receptor-positive tumor cells in paraffin-embedded breast carcinomas.

BACKGROUND: For 4 years we used a multiparameter DNA flow cytometric (MP-FCM) technique to assess steroid hormone receptor expression in the diagnostic workup of routinely processed formalin-fixed, paraffin-embedded breast carcinomas as an alternative to immunohistochemistry (IHC) for the quantification of hormone receptor-positive cells. In all cases a positive fraction of hormone receptor-expressing epithelial cells was detected. This observation raised the question of what the cutoff value might be to distinguish receptor-negative from receptor-positive tumors. METHODS: In our search for a possible threshold value of positivity for estrogen receptor (ER) and progesterone receptor (PR) in MP-FCM, we developed four steps. First, we compared IHC results in our own laboratory with the results obtained by MP-FCM on a small series of breast tumors (n = 42). Second, after collecting our first 843 tumors, we made a comparison with the literature of the distribution of receptor positivity according to age classes. Third, using the most likely threshold that resulted from this comparison, we compared a subset of 340 node-negative tumors for their combined ER/PR profiles with the data from a similar group of node-negative tumor cases from the National Cancer Institute's Surveillance, Epidemiology and End-Result (SEER) study. Fourth, with the results of these comparisons, we prospectively collected IHC data and MP-FCM results of the same tumor samples for a period of 1 year. In this way, we collected data for an additional 180 tumors. RESULTS: The first step in this process resulted in an previous publication where 20% of steroid hormone receptor-positive cells seemed to be an acceptable cutoff point for positivity. However, the second step provided the best correlation at approximately 35% of ER reactive cells in the cytokeratin-positive cell population. With this cutoff, the distribution of combined ER/PR profiles in our patient population of node-negative breast cancers also showed a distribution similar to the data from the SEER study. The fourth step, using the 35% threshold value, resulted in a good correlation (r = 0.85, P < 0.0001) for ER and PR between IHC and MP-FCM in the 180 tumors investigated. CONCLUSION: By comparing in-house data with those from large external data collections in the literature, a threshold percentage can be defined that distinguishes steroid hormone receptor-negative from hormone receptor-positive tumors. As a result, information about DNA content and cell cycle distribution can be obtained. This observational study provides additional support to our opinion that MP-FCM is an alternative for IHC determination of ER and PR positivity. It is more objective and quantification can be done more appropriately. The additional value of this approach is that we generate continuous variables of ER/PR content instead of categorical classes, which can be used at different threshold levels for evaluation of clinical relevance.

Surfactant proteins in pulmonary alveolar proteinosis in adults.

Pulmonary alveolar proteinosis (PAP) is a rare disorder characterised histologically by an intra-alveolar accumulation of fine granular eosinophilic and periodic acid-Schiff positive material. In a retrospective study, the composition of the intra-alveolarly accumulated material of adult patients with PAP was analysed by means of immunohistochemistry and Western blotting. In patients with PAP, the current authors found an intra-alveolar accumulation of surfactant protein (SP)-A, precursors of SP-B, SP-B, variable amounts of mono-, di-, and oligomeric SP-C forms, as well as SP-D. Only in one patient was a precursor of SP-C detected. By means of immuno-electron microscopy, the current authors identified not only transport vesicles labelled for precursors of SP-B and SP-C, but also transport vesicles containing either precursors of SP-B or SP-C in type-II pneumocytes in normal human lungs. It is concluded that pulmonary alveolar proteinosis in adults is characterised by an intra-alveolar accumulation of surfactant protein A, precursors of surfactant protein B, and surfactant proteins B, C and D. The current data provide evidence that not only an impairment of surfactant clearance by alveolar macrophages, but also an abnormal secretion of transport vesicles containing precursors of surfactant protein B (but not surfactant protein C) and an insufficient palmitoylation of surfactant protein C, which may lead to the formation of di- and oligomeric surfactant protein C forms, play a role in the pathogenesis of pulmonary alveolar proteinosis.

Interstitial lung disease in a baby with a de novo mutation in the SFTPC gene.

Mutations in the surfactant protein C gene (SFTPC) were recently reported in patients with interstitial lung disease. In a 13-month-old infant with severe respiratory insufficiency, a lung biopsy elicited combined histological patterns of nonspecific interstitial pneumonia and pulmonary alveolar proteinosis. Immunohistochemical and biochemical analyses showed an intra-alveolar accumulation of surfactant protein (SP)-A, precursors of SP-B, mature SP-B, aberrantly processed proSP-C, as well as mono- and dimeric SP-C. Sequencing of genomic DNA detected a de novo heterozygous missense mutation of the SFTPC gene (g.1286T>C) resulting in a substitution of threonine for isoleucine (173T) in the C-terminal propeptide. At the ultrastructural level, abnormal transport vesicles were detected in type-II pneumocytes. Fusion proteins, consisting of enhanced green fluorescent protein and wild-type or mutant proSP-C, were used to evaluate protein trafficking in vitro. In contrast to wild-type proSP-C, mutant proSP-C was routed to early endosomes when transfected into A549 epithelial cells. In contrast to previously reported mutations, the 173T represents a new class of surfactant protein C gene mutations, which is marked by a distinct trafficking, processing, palmitoylation, and secretion of the mutant and wild-type surfactant protein C. This report heralds the emerging diversity of phenotypes associated with the expression of mutant surfactant C proteins.

Methicillin-resistant Staphylococcus aureus bacteraemia in Western Australian teaching hospitals, 1997-1999: risk factors, outcomes and implications for management.

The aim of this study was to document the evolution of methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia at teaching hospitals in Perth, Western Australia (WA), and determine the risk factors and outcomes of the disease. We performed a retrospective case series analysis of all laboratory-confirmed episodes of S. aureus bacteraemia at Perth teaching hospitals between 1 July 1997 and 30 June 1999 by linking laboratory data with hospitalization data from the state's Hospital Morbidity Data System. Episodes of S. aureus bacteraemia were stratified according to methicillin susceptibility and the relationship between methicillin resistance and key factors or outcomes was determined. Almost 11% of episodes of S. aureus bacteraemia (55/509) were caused by MRSA. On age-adjusted multivariate analysis, Aboriginality (RR 6.71, 95% CI 3.20-14.10, P<0.001), geriatric unit admission (RR 5.74, 95% CI 2.01-16.37, P=0.001), female sex (RR 1.88, 95% CI 1.03-3.42, P=0.04) and healthcare-associated disease (RR 1.93, 95% CI 1.01-3.70, P=0.05) were independently associated with MRSA bacteraemia. Outcomes among those with MRSA bacteraemia included death in 15 patients and re-admission for an MRSA-related complication in five. Empirical use of vancomycin needs consideration in at-risk patients in whom Gram-positive bacteraemia is suspected clinically, with prompt review of therapy once antibiotic susceptibility results are known. The rates of re-admission after discharge for MRSA bacteraemia could be used as a clinical indicator to monitor the quality of care in hospitals.

Pilot study of antibiotic cycling in a pediatric intensive care unit.

OBJECTIVE: This pilot study was performed to determine the safety and size of effect of antibiotic cycling to reduce colonization and infection with antibiotic-resistant bacteria. DESIGN: Open, observational study. SETTING: The study was performed in a 16-bed pediatric medical-surgical intensive care unit. PATIENTS: Critically ill children requiring antibiotic therapy. INTERVENTIONS: Three antibiotic classes were systematically cycled for 3-month intervals over 18 months. Antibiotic regimens were used for all empirical therapy and continued if the bacterial isolate was susceptible. MEASUREMENTS: The primary outcome was colonization with antibiotic-resistant bacteria, determined by surveillance cultures obtained twice monthly from all patients in the unit. Rates of antibiotic-resistant, nosocomial blood stream infections, and risks of colonization over calendar time in the intensive care unit were also evaluated. MAIN RESULTS: The cycling of broad-spectrum, empirical antibiotics was safe and did not generate increased antibiotic resistance nor select for new organisms. Over the study period, the trend in prevalence of children colonized with antibiotic-resistant bacteria was from 29% to 24% (p =.41). The effect on prevalence of resistant blood stream infections was similar (p =.29). Changes in individual risks of colonization with resistant bacteria over calendar time were consistent with the ecologic effect in size and direction. CONCLUSIONS: Results of this pilot intervention suggest that cycling antibiotics may be a safe and viable strategy to minimize the emergence of antibiotic resistance in intensive care units. A definitive study will require a randomized and controlled trial of only four pediatric intensive care units over an 18-month period.

The impact of diagnosis by legionella urinary antigen test on the epidemiology and outcomes of Legionnaires' disease.

Legionnaires' disease is an uncommon but important cause of life-threatening community-acquired or nosocomial pneumonia. The urinary antigen enzyme immunoassay test, used in Victoria since 1995, now accounts for the majority of initial laboratory notifications (81% in 1999). We review the impact of the test on the disease epidemiology and the public health investigative process. We focus on the major subgroup of cases due to Legionella pneumophila serogroup 1, comparing delays until notification and mortality for urinary antigen detected cases with culture detected cases. The urinary antigen test facilitates a 5-day reduction for the delay between onset of illness and notification. We observed that there was minimal clinical heterogeneity of urinary antigen detected cases whether they were subsequently culture confirmed or not. We encourage clinician use of the urinary antigen test in cases of community-acquired pneumonia where Legionnaires' disease is a possible diagnosis, in conjunction with culture of clinical specimens.

Synthesis and post-translational processing of surfactant protein C.

Traditional thinking about surfactant proteins has centered around their effects on the biophysical properties of surfactant phospholipids. Accumulated data now suggests that the four major surfactant proteins (SPs) are a biochemically and functionally diverse group of mammalian peptides that have function beyond modification of alveolar surface tension. Alveolar SP-C (SP-C3.7, Mr 21,000) is 35 amino acid peptide isolated from lung surfactant that is synthesized and processed from a 191-197 amino acid precursor (proSP-C21). Although its solubility in organic solvents and avidity for lipid membranes impart properties important for its biophysical activity, SP-C represents a structurally and functionally challenging protein for the alveolar type II cell that must synthesize and traffic the peptide through the regulated secretory pathway. Despite technical and analytical difficulties imposed by its unique structure, our current understanding of SP-C biosynthesis has evolved over the past 10 years. Recent data now require us to consider proSP-C21 as a hybrid molecule incorporating structural and functional features both of bitopic integral membrane proteins as well us more classically recognized propeptide hormones. Our article highlights major developments related to characterization of molecular and cellular mechanisms underlying expression, post-translational processing, and targeting of proSP-C21 that result in production of secreted SP-C3.7.

Maintenance of differentiated function of the surfactant system in human fetal lung type II epithelial cells cultured on plastic.

We report a simplified culture system for human fetal lung type II cells that maintains surfactant expression. Type II cells isolated from explant cultures of hormone-treated lungs (18-22 wk gestation) by collagenase + trypsin digestion were cultured on plastic for 4 days in serum-free medium containing dexamethasone (Dex, 10 nM) + 8-bromo-cAMP (0.1 mM + isobutylmethylxanthine (0.1 mM) or were untreated (control). Surfactant protein (SP) mRNAs decreased markedly in control cells between days 1 and 4 of culture, but mRNA levels were high in treated cells on day) 4 (SP-A, SP-B, SP-C, SP-D; 600%, 100%, 85%, 130% of day 0 content, respectively). Dex or cAMP alone increased SP-B, SP-C, and SP-D mRNAs and together had additive effects. The greatest increase in SP-A mRNA occurred with cAMP alone. Treated cells processed pro-SP-B and pro-SP-C proteins to mature forms and had a higher rate of phosphatidylcholine (PC) synthesis (2-fold) and higher saturation of PC (approximately 34% versus 27%) than controls. Only treated cells maintained secretagogue-responsive phospholipid synthesis. By electron microscopy, the treated cells retained lamellar bodies and extensive microvilli. We conclude that Dex and cAMP additively stimulate expression of surfactant components in isolated fetal type II cells, providing a simplified culture system for investigation of surfactant-related, and perhaps other, type II cell functions.

Abattoir-associated Q fever: a Q fever outbreak during a Q fever vaccination program.

OBJECTIVES: To investigate an abattoir outbreak of Q fever in southem New South Wales with reference to the protective effect and safety of the formalin-inactivated Q fever vaccine (Q Vax) administered before and during the outbreak. METHODS: In September 1998, after notification of four Q fever cases in the abattoir, a cohort investigation of 103 workers was undertaken. Data on age, sex, immune status, vaccination status and main work area were obtained from the medical officer administering the vaccination program and abattoir records. Symptoms and occupational risk factors for illness were obtained from interview of 63 (61%) employees. RESULTS: Of 103 abattoir employees, 16 (16%) had immunity from previous Q fever exposure and 19 (18 %) had been vaccinated at least six weeks before the first case of Q fever exposure in the abattoir. Of the remaining 68 workers who were susceptible to primary infection, 29 (43%) had laboratory confirmed acute primary Q fever and eight were suspected cases. No workers vaccinated before the likely period of exposure developed Q fever. Of 32 workers vaccinated post-exposure, four developed laboratory-confirmed Q fever within eight days of vaccination. Vaccination administered 10 or more days after the likely period of exposure showed no significant protective effect (RR=0.57; 95% CI 0.13-2.57; p=0.60). CONCLUSIONS: Q-Vax was highly effective when administered in advance of the likely period of Q fever exposure. Post exposure vaccination was not shown to be protective. IMPLICATIONS: This study reinforces meat industry vaccination guidelines for abattoir employees. The optimal time to vaccinate workers is before they are put at occupational risk.

Respiratory distress after intratracheal bleomycin: selective deficiency of surfactant proteins B and C.

Intratracheal bleomycin in rats is associated with respiratory distress of uncertain etiology. We investigated the expression of surfactant components in this model of lung injury. Maximum respiratory distress, determined by respiratory rate, occurred at 7 days, and surfactant dysfunction was confirmed by increased surface tension of the large-aggregate fraction of bronchoalveolar lavage (BAL). In injured animals, phospholipid content and composition were similar to those of controls, mature surfactant protein (SP) B was decreased 90%, and SP-A and SP-D contents were increased. In lung tissue, SP-B and SP-C mRNAs were decreased by 2 days and maximally at 4--7 days and recovered between 14 and 21 days after injury. Immunostaining of SP-B and proSP-C was decreased in type II epithelial cells but strong in macrophages. By electron microscopy, injured lungs had type II cells lacking lamellar bodies and macrophages with phagocytosed lamellar bodies. Surface activity of BAL phospholipids of injured animals was restored by addition of exogenous SP-B. We conclude that respiratory distress after bleomycin in rats results from surfactant dysfunction in part secondary to selective downregulation of SP-B and SP-C.

Aspergillus fumigatus-induced allergic airway inflammation alters surfactant homeostasis and lung function in BALB/c mice.

The differential regulation of pulmonary surfactant proteins (SPs) is demonstrated in a murine model of Aspergillus fumigatus (Af )-induced allergic airway inflammation and hyperresponsiveness. BALB/c mice were sensitized intraperitoneally and challenged intranasally with Af extract. Enzyme-linked immunosorbent assay analysis of serum immunoglobulin (Ig) levels in these mice showed markedly increased total IgE and Af-specific IgE and IgG1. This was associated with peribronchial/perivascular tissue inflammation, airway eosinophilia, and secretion of interleukin (IL)-4 and IL-5 into the bronchoalveolar lavage fluid (BALF). Functional analysis revealed that in comparison with nonsensitized mice, allergic sensitization and challenge resulted in significant increases in acetylcholine responsiveness. To analyze levels of SPs, the cell-free supernate of the BALF was further fractionated by high-speed (20,000 x g) centrifugation. After sensitization and challenges, the pellet (large-aggregate fraction) showed a selective downregulation of hydrophobic SPs SP-B and SP-C by 50%. This reduction was reflected by commensurate decreases in SP-B and SP-C messenger RNA (mRNA) expression of the lung tissue of these animals. In contrast, there was a 9-fold increase in SP-D protein levels in the 20,000 x g supernate without changes in SP-D mRNA. The increased levels of SP-D showed a significant positive correlation with serum IgE (r = 0.85, P < 0.001). Tissue mRNA and protein levels of SP-A in either the large- or the small-aggregate fractions were unaffected. Our data indicate that allergic airway inflammation induces selective inhibition of hydrophobic SP synthesis accompanied by marked increases in the lung collectin SP-D protein content of BALF. These changes may contribute significantly to the pathophysiology of Af-induced allergic airway hyperresponsiveness.