Combined pH ratiometry and fluorescence lectin-binding analysis (pH-FLBA) for microscopy-based analyses of biofilm pH and matrix carbohydrates

Bacterial biofilms have a complex and heterogeneous three-dimensional architecture that is characterized by chemically and structurally distinct microenvironments. Confocal microscopy-based pH ratiometry and fluorescence lectin-binding analysis (FLBA) are well-established methods to characterize pH developments and the carbohydrate matrix architecture of biofilms at the microscale. Here, we developed a combined analysis, pH-FLBA, to concomitantly map biofilm pH and the distribution of matrix carbohydrates in bacterial biofilms while preserving the biofilm microarchitecture. As a proof of principle, the relationship between pH and the presence of galactose- and fucose-containing matrix components was investigated in dental biofilms grown with and without sucrose. The pH response to a sucrose challenge was monitored in different areas at the biofilm base using the ratiometric pH-sensitive dye C-SNARF-4. Thereafter, the fucose- and galactose-specific fluorescently labeled lectins Aleuria aurantia lectin (AAL) and Morus nigra agglutinin G (MNA-G) were used to visualize carbohydrate matrix components in the same biofilm areas and their immediate surroundings. Sucrose during growth significantly decreased biofilm pH (P < 0.05) and increased the amounts of both MNA-G- and AAL-targeted matrix carbohydrates (P < 0.05). Moreover, it modulated the biofilm composition towards a less diverse community dominated by streptococci, as determined by 16S rRNA gene sequencing. Altogether, these results suggest that the production of galactose- and fucose-containing matrix carbohydrates is related to streptococcal metabolism and, thereby, pH profiles in dental biofilms. In conclusion, pH-FLBA using lectins with different carbohydrate specificities is a useful method to investigate the association between biofilm pH and the complex carbohydrate architecture of bacterial biofilms.IMPORTANCEBiofilm pH is a key regulating factor in several biological and biochemical processes in environmental, industrial, and medical biofilms. At the microscale, microbial biofilms are characterized by steep pH gradients and an extracellular matrix rich in carbohydrate components with diffusion-modifying properties that contribute to bacterial acid-base metabolism. Here, we propose a combined analysis of pH ratiometry and fluorescence lectin-binding analysis, pH-FLBA, to concomitantly investigate the matrix architecture and pH developments in microbial biofilms, using complex saliva-derived biofilms as an example. Spatiotemporal changes in biofilm pH are monitored non-invasively over time by pH ratiometry, while FLBA with lectins of different carbohydrate specificities allows mapping the distribution of multiple relevant matrix components in the same biofilm areas. As the biofilm structure is preserved, pH-FLBA can be used to investigate the in situ relationship between the biofilm matrix architecture and biofilm pH in complex multispecies biofilms.

Does ecological drift explain variation in microbiome composition among groups in a social host species?

Within a given species, considerable inter-individual, spatial, and temporal variation in the composition of the host microbiome exists. In group-living animals, social interactions homogenize microbiome composition among group members, nevertheless divergence in microbiome composition among related groups arise. Such variation can result from deterministic and stochastic processes. Stochastic changes, or ecological drift, can occur among symbionts with potential for colonizing a host and within individual hosts, and drive divergence in microbiome composition among hosts or host groups. We tested whether ecological drift associated with dispersal and foundation of new groups cause divergence in microbiome composition between natal and newly formed groups in the social spider Stegodyphus dumicola. We simulated the initiation of new groups by splitting field-collected nests into groups of 1, 3, and 10 individuals respectively, and compared variation in microbiome composition among and within groups after 6 weeks using 16S rRNA gene sequencing. Theory predicts that ecological drift increases with decreasing group size. We found that microbiome composition among single founders was more dissimilar than among individuals kept in groups, supporting this prediction. Divergence in microbiome composition from the natal nest was mainly driven by a higher number of non-core symbionts. This suggests that stochastic divergence in host microbiomes can arise during the process of group formation by individual founders, which could explain the existence of among-group variation in microbiome composition in the wild. Individual founders appear to harbour higher relative abundances of non-core symbionts compared with founders in small groups, some of which are possible pathogens. These symbionts vary in occurrence with group size, indicating that group dynamics influence various core and non-core symbionts differently.

Determinants of Microscale pH in In Situ-Grown Dental Biofilms

Dental biofilm pH is the most important determinant of virulence for the development of caries lesions. Confocal microscopy-based pH ratiometry allows monitoring biofilm pH with high spatial resolution. Experiments performed on simplified biofilm models under static conditions identified steep pH gradients as well as localized acidogenic foci that promote enamel demineralization. The present work used pH ratiometry to perform a comprehensive analysis of the effect of whole saliva flow on the microscale pH in complex, in situ-grown 48-h and 96-h biofilms (n = 54) from 9 healthy participants. pH was monitored in 12 areas at the biofilm bottom and top, and saliva flow with film thicknesses corresponding to those in the oral cavity was provided by an additively manufactured microfluidic flow cell. Biofilm pH was correlated to the bacterial composition, as determined by 16S rRNA gene sequencing. Biofilm acidogenicity varied considerably between participants and individual biofilms but also between different areas inside one biofilm, with pH gradients of up to 2 units. pH drops were more pronounced in 96-h than in 48-h biofilms (P = 0.0121) and virtually unaffected by unstimulated saliva flow (0.8 mm/min). Stimulated flow (8 mm/min) raised average biofilm pH to near-neutral values but it did not equilibrate vertical and horizontal pH gradients in the biofilms. pH was significantly lower at the biofilm base than at the top (P < 0.0001) and lower downstream than upstream (P = 0.0046), due to an accumulation of acids along the flow path. pH drops were positively correlated with biofilm thickness and negatively with the thickness of the saliva film covering the biofilm. Bacterial community composition was significantly different between biofilms with strong and weak pH responses but not their species richness. The present experimental study demonstrates that stimulated saliva flow, saliva film thickness, biofilm age, biofilm thickness, and bacterial composition are important modulators of microscale pH in dental biofilms.

Adapting to climate with limited genetic diversity: Nucleotide, DNA methylation and microbiome variation among populations of the social spider Stegodyphus dumicola

Understanding the role of genetic and nongenetic variants in modulating phenotypes is central to our knowledge of adaptive responses to local conditions and environmental change, particularly in species with such low population genetic diversity that it is likely to limit their evolutionary potential. A first step towards uncovering the molecular mechanisms underlying population-specific responses to the environment is to carry out environmental association studies. We associated climatic variation with genetic, epigenetic and microbiome variation in populations of a social spider with extremely low standing genetic diversity. We identified genetic variants that are associated strongly with environmental variation, particularly with average temperature, a pattern consistent with local adaptation. Variation in DNA methylation in many genes was strongly correlated with a wide set of climate parameters, thereby revealing a different pattern of associations than that of genetic variants, which show strong correlations to a more restricted range of climate parameters. DNA methylation levels were largely independent of cis-genetic variation and of overall genetic population structure, suggesting that DNA methylation can work as an independent mechanism. Microbiome composition also correlated with environmental variation, but most strong associations were with precipitation-related climatic factors. Our results suggest a role for both genetic and nongenetic mechanisms in shaping phenotypic responses to local environments.

Fluorescence lectin binding analysis of carbohydrate components in dental biofilms grown in situ in the presence or absence of sucrose

Carbohydrate components, such as glycoconjugates and polysaccharides, are constituents of the dental biofilm matrix that play an important role in biofilm stability and virulence. Exopolysaccharides in Streptococcus mutans biofilms have been characterized extensively, but comparably little is known about the matrix carbohydrates in complex, in situ-grown dental biofilms. The present study employed fluorescence lectin binding analysis (FLBA) to investigate the abundance and spatial distribution of glycoconjugates/polysaccharides in biofilms (n = 306) from 10 participants, grown in situ with (SUC) and without (H2O) exposure to sucrose. Biofilms were stained with 10 fluorescently labeled lectins with different carbohydrate specificities (AAL, ABA, ASA, HPA, LEA, MNA-G, MPA, PSA, VGA and WGA) and analyzed by confocal microscopy and digital image analysis. Microbial composition was determined by 16S rRNA gene sequencing. With the exception of ABA, all lectins targeted considerable matrix biovolumes, ranging from 19.3% to 194.0% of the microbial biovolume in the biofilms, which illustrates a remarkable variety of carbohydrate compounds in in situ-grown dental biofilms. MNA-G, AAL, and ASA, specific for galactose, fucose, and mannose, respectively, stained the largest biovolumes. AAL and ASA biovolumes were increased in SUC biofilms, but the difference was not significant due to considerable biological variation. SUC biofilms were enriched in streptococci and showed reduced abundances of Neisseria and Haemophilus spp., but no significant correlations between lectin-stained biovolumes and bacterial abundance were observed. In conclusion, FLBA demonstrates the presence of a voluminous biofilm matrix comprising a variety of different carbohydrate components in complex, in situ-grown dental biofilms.

Triculamin: An Unusual Lasso Peptide with Potent Antimycobacterial Activity

Lasso peptides are ribosomally synthesized and post-translationally modified peptides (RiPPs) produced by microorganisms. Here we show that the two natural products triculamin and alboverticillin, originally isolated in 1967 and 1958, respectively, with potent and specific activity against mycobacteria are in fact the same lasso peptide. We solved the structure using 2D NMR spectroscopy and expanded on the previously reported bioactivity. Through genome sequencing, we identify the responsible biosynthetic gene clusters, which curiously revealed that, unlike any known lasso peptides, their precursor peptides appear to have a follower instead of a leader peptide.

Metabolite Profiling of the Social Spider Stegodyphus dumicola Along a Climate Gradient

Animals experience climatic variation in their natural habitats, which may lead to variation in phenotypic responses among populations through local adaptation or phenotypic plasticity. In ectotherm arthropods, the expression of thermoprotective metabolites such as free amino acids, sugars, and polyols, in response to temperature stress, may facilitate temperature tolerance by regulating cellular homeostasis. If populations experience differences in temperatures, individuals may exhibit population-specific metabolite profiles through differential accumulation of metabolites that facilitate thermal tolerance. Such thermoprotective metabolites may originate from the animals themselves or from their associated microbiome, and hence microbial symbionts may contribute to shape the thermal niche of their host. The social spider Stegodyphus dumicola has extremely low genetic diversity, yet it occupies a relatively broad temperature range occurring across multiple climate zones in Southern Africa. We investigated whether the metabolome, including thermoprotective metabolites, differs between populations, and whether population genetic structure or the spider microbiome may explain potential differences. To address these questions, we assessed metabolite profiles, phylogenetic relationships, and microbiomes in three natural populations along a temperature gradient. The spider microbiomes in three genetically distinct populations of S. dumicola showed no significant population-specific pattern, and none of its dominating genera (Borrelia, Diplorickettsia, and Mycoplasma) are known to facilitate thermal tolerance in hosts. These results do not support a role of the microbiome in shaping the thermal niche of S. dumicola. Metabolite profiles of the three spider populations were significantly different. The variation was driven by multiple metabolites that can be linked to temperature stress (e.g., lactate, succinate, or xanthine) and thermal tolerance (e.g., polyols, trehalose, or glycerol): these metabolites had higher relative abundance in spiders from the hottest geographic region. These distinct metabolite profiles are consistent with a potential role of the metabolome in temperature response.

Microbiomes and Specific Symbionts of Social Spiders: Compositional Patterns in Host Species, Populations, and Nests

Social spiders have remarkably low species-wide genetic diversities, potentially increasing the relative importance of microbial symbionts for host fitness. Here we explore the bacterial microbiomes of three species of social Stegodyphus (S. dumicola, S. mimosarum, and S. sarasinorum), within and between populations, using 16S rRNA gene amplicon sequencing. The microbiomes of the three spider species were distinct but shared similarities in membership and structure. This included low overall diversity (Shannon index 0.5–1.7), strong dominance of single symbionts in individual spiders (McNaughton’s dominance index 0.68–0.93), and a core microbiome (>50% prevalence) consisting of 5–7 specific symbionts. The most abundant and prevalent symbionts were classified as Chlamydiales, Borrelia, and Mycoplasma, all representing novel, presumably Stegodyphus-specific lineages. Borrelia- and Mycoplasma-like symbionts were localized by fluorescence in situ hybridization (FISH) in the spider midgut. The microbiomes of individual spiders were highly similar within nests but often very different between nests from the same population, with only the microbiome of S. sarasinorum consistently reflecting host population structure. The weak population pattern in microbiome composition renders microbiome-facilitated local adaptation unlikely. However, the retention of specific symbionts across populations and species may indicate a recurrent acquisition from environmental vectors or an essential symbiotic contribution to spider phenotype.

Gene expression of terminal oxidases in two marine bacterial strains exposed to nanomolar oxygen concentrations

The final step of aerobic respiration is carried out by a terminal oxidase transporting electrons to oxygen (O2). Prokaryotes harbor diverse terminal oxidases that differ in phylogenetic origin, structure, biochemical function, and affinity for O2. Here we report on the expression of high-affinity (cytochrome cbb3 oxidase), low-affinity (cytochrome aa3 oxidase), and putative low-affinity (cyanide-insensitive oxidase (CIO)) terminal oxidases in the marine bacteria Idiomarina loihiensis L2-TR and Marinobacter daepoensis SW-156 upon transition to very low O2 concentrations (<200 nM), measured by RT-qPCR. In both strains, high-affinity cytochrome cbb3 oxidase showed the highest expression levels and was significantly up-regulated upon transition to low O2 concentrations. Low-affinity cytochrome aa3 oxidase showed very low transcription levels throughout the incubation. Surprisingly, however, it was also up-regulated upon transition to low O2 concentrations. In contrast, putative low-affinity CIO had much lower expression levels and markedly different regulation patterns between the two strains. These results demonstrate that exposure to low O2 concentrations regulates the gene expression of different types of terminal oxidases, but also that the type and magnitude of transcriptional response is species-dependent. Therefore, in situ transcriptome data cannot, without detailed knowledge of the transcriptional regulation of the species involved, be translated into relative respiratory activity.

Pulmonary function and blood gases after gastric bypass and lifestyle intervention: a comparative study

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Impaired lung function associated with obesity improves with weight loss.

WHAT THIS STUDY ADDS

This is the first study to compare the effects of obesity surgery and intensive lifestyle intervention on pulmonary function and arterial blood gases. Arterial oxygenation and pulmonary function improved to a greater extent after gastric bypass than after lifestyle intervention. The superiority of surgical treatment might be mediated by greater weight loss after gastric bypass. Impaired lung function associated with obesity improves with weight loss. The effects of obesity surgery and intensive lifestyle intervention on pulmonary function and arterial blood gases have not previously been subjected to comparative examination. In this 1-year non-randomized controlled clinical trial (ClinicalTrials.gov identifier NCT00273104), 139 morbidly obese subjects (19-66 years, mean [standard deviation] body mass index [BMI] 45.1 kg m(-2) [5.6], 107 women) were treated with either Roux-en-Y gastric bypass surgery (n = 76) or intensive lifestyle intervention (n = 63). Mean weight reduction was 30 (8)% and 8 (9)%, respectively. Dynamic and static lung volumes, gas diffusing capacity and arterial blood gases were measured. Compared with lifestyle intervention, surgery resulted in a significantly greater increase in forced vital capacity (mean [95% confidence interval] between-group difference, 7 [4-10]%), forced expiratory volume in 1 s (7 [5-9]%), total lung capacity (5 [1-8]%), vital capacity (7 [4-9]%), functional residual capacity (18 [12-24]%), expiratory reserve volume (48 [30-66]%) and partial pressure of oxygen in arterial blood (0.5 [0.0-1.0] kPa). These associations either disappeared or diminished after adjusting for weight loss. Reduced central adiposity (waist circumference and waist-to-hip ratio) and systemic inflammation (C-reactive protein and adiponectin) had no effect on pulmonary function beyond the effect of reduced general adiposity (BMI). In morbidly obese subjects, gastric bypass surgery is more effective than lifestyle intervention at improving arterial oxygenation and pulmonary function. The effect might be mediated by greater weight loss after surgical treatment.

Severe chronic obstructive pulmonary disease: association with marginal bone loss in periodontitis

An association between chronic marginal periodontitis and chronic obstructive pulmonary disease (COPD) has been suggested. The aim of this study was to investigate whether chronic marginal periodontitis is more prevalent in very severe COPD than in other very severe respiratory diseases, and whether periodontitis in COPD is related to risk factors for periodontitis that are often present in COPD subjects. Orthopantomograms were collected from 130 patients with COPD and 50 patients with non-COPD evaluated for lung transplantation. Chronic marginal periodontitis was defined as a general marginal bone level > or = 4 mm. The prevalence of periodontitis was 44% in the COPD group vs. 7.3% in the non-COPD group. All oral measurements differed significantly between the groups. The difference in mean marginal bone level remained statistically significant when adjusting for age, gender and pack years smoked. In logistic regression analysis mean marginal bone level > or = 4 mm was identified as a factor significantly associated with severe COPD. This study demonstrates that chronic marginal periodontitis is common in patients with severe COPD. The high prevalence of periodontitis in COPD patients appears to be independent of possible risk factors for periodontitis such as age, pack years smoked, body mass index, use of corticosteroids and bone mineral density.

Genetic and environmental effects on exhaled nitric oxide and airway responsiveness in a population-based sample of twins

Elevated levels of exhaled nitric oxide (eNO) and airway hyperresponsiveness are intermediate phenotypes of asthma. Using population-based data collected from a sample of twins, the present authors estimated the relative contribution of genes, family environment and nonshared environmental influences to variations in eNO and airway responsiveness (AR). In addition, the genetic and environmental sources of covariation between these two asthma-related phenotypes were investigated. The study population comprised a random sample of 377 adult twins identified through the Norwegian Twin Registry. The main outcome variables were eNO and AR to methacholine. Genetic effects accounted for 60% of the variation in eNO. Family environment accounted for 30% of the variation in AR, while nonshared environmental influences explained the remaining variation for both measures. For both eNO and AR, there were significant regression effects for atopy and smoking. The small, but significant association between eNO and AR was primarily explained by genetic factors. Sub-analyses restricted to atopic and nonsmoking twins strengthened the observation. In conclusion, variations in exhaled nitric oxide and airway responsiveness appear to be explained by different genetic and environmental variance structures. Variation in exhaled nitric oxide is explained by genetic and nonshared environmental effects, whereas an environmental model best explains the variation in airway responsiveness. Common genetic effects explain the small but significant association between exhaled nitric oxide and airway responsiveness.

Airway inflammation in aluminium potroom asthma

AIMS

To examine whether asthma induced by exposure to aluminium potroom emissions (potroom asthma) is associated with inflammatory changes in the airways.

METHODS

Bronchial biopsy specimens from 20 asthmatic workers (8 non-smokers and 12 smokers), 15 healthy workers (8 non-smokers and 7 smokers), and 10 non-exposed controls (all non-smokers) were analysed. Immunohistofluorescent staining was performed to identify mucosal total leucocytes (CD45+ leucocytes), neutrophils, and mast cells.

RESULTS

Median RBM thickness was significantly increased in both asthmatic workers (8.2 microm) and healthy workers (7.4 microm) compared to non-exposed controls (6.7 microm). Non-smoking asthmatic workers had significantly increased median density of lamina propria CD45+ leucocytes (1519 cells/mm2 v 660 and 887 cells/mm2) and eosinophils (27 cells/mm2 v 10 and 3 cells/mm2) and significantly increased concentrations of exhaled NO (18.1 ppb v 6.5 and 5.1 ppb) compared to non-smoking healthy workers and non-exposed controls. Leucocyte counts and exhaled NO concentrations varied with smoking habits and fewer leucocytes were observed in asthmatic smokers than in non-smokers Asthmatic smokers had significantly increased numbers of eosinophils in lamina propria compared to non-exposed controls (10 v 3 cells/mm2). Both eosinophilic and non-eosinophilic phenotypes of asthma were recognised in the potroom workers and signs of airway inflammation were also observed in healthy workers.

CONCLUSIONS

Airway inflammation is a central feature of potroom asthma and exposure to potroom emissions induces pathological alterations similar to those described in other types of asthma. Cigarette smoking seems to affect the underlying mechanisms involved in asthma, as the cellular composition of airway mucosa appears different in asthmatic smokers and non-smokers.

Lung function 5 yrs after allogeneic bone marrow transplantation conditioned with busulphan and cyclophosphamide

Long-term data on lung function after bone marrow transplantation (BMT) are inconclusive. Previously, a persistent reduction in gas transfer 1 yr after allogeneic BMT with busulphan and cyclophosphamide conditioning was reported by the current authors. In the present study this reduction was examined to see if it was permanent, transient or progressive. Prospectively, 43 consecutive adult patients with malignant blood disorders undertook lung function measurements prior to BMT, at 3 month intervals during the 1st yr after BMT and finally after 5 yrs. Mean baseline lung function values were >90% predicted. Within the 1st yr after BMT a transient decline in lung volumes and a persistent reduction in gas transfer were observed. After 5 yrs, baseline values were restored for all variables, except in four patients who developed obliterative bronchiolitis. Acute leukaemia and smoking were independently associated with gas transfer reductions at baseline and during the 1st yr after BMT. Allogeneic bone marrow transplantation with busulphan and cyclophosphamide conditioning was associated with a reduction in gas transfer 1 yr after bone marrow transplantation but baseline values were usually restored after 5 yrs. Since recovery may be gradual and slow, an observation period >1 yr is required before drawing conclusions concerning the development of a permanent reduction in lung function after allogeneic bone marrow transplantation conditioned with busulphan and cyclophosphamide.

Cumulative exposure to dust causes accelerated decline in lung function in tunnel workers

OBJECTIVES

To examine whether underground construction workers exposed to tunnelling pollutants over a follow up period of 8 years have an increased risk of decline in lung function and respiratory symptoms compared with reference subjects working outside the tunnel atmosphere, and relate the findings to job groups and cumulative exposure to dust and gases.

METHODS

96 Tunnel workers and a reference group of 249 other heavy construction workers were examined in 1991 and re-examined in 1999. Exposure measurements were carried out to estimate personal cumulative exposure to total dust, respirable dust, alpha-quartz, oil mist, and nitrogen dioxide. The subjects answered a questionnaire on respiratory symptoms and smoking habits, performed spirometry, and had chest radiographs taken. Radiological signs of silicosis were evaluated (International Labour Organisation (ILO) classification). Atopy was determined by a multiple radioallergosorbent test (RAST).

RESULTS

The mean exposure to respirable dust and alpha-quartz in tunnel workers varied from 1.2-3.6 mg/m3 (respirable dust) and 0.019-0.044 mg/m3 (alpha-quartz) depending on job task performed. Decrease in forced expiratory volume in 1 second (FEV1) was associated with cumulative exposure to respirable dust (p<0.001) and alpha-quartz (p=0.02). The multiple regression model predicted that in a worker 40 years of age, the annual decrease in FEV1 would be 25 ml in a non-exposed non-smoker, 35 ml in a non-exposed smoker, and 50-63 ml in a non-smoking tunnel worker (depending on job). Compared with the reference group the odds ratio for the occurrence of new respiratory symptoms during the follow up period was increased in the tunnel workers and associated with cumulative exposure to respirable dust.

CONCLUSIONS

Cumulative exposures to respirable dust and alpha-quartz are the most important risk factors for airflow limitation in underground heavy construction workers, and cumulative exposure to respirable dust is the most important risk factor for respiratory symptoms. The finding of accelerated decline in lung function in tunnel workers suggests that better control of exposures is needed.

Effects of blasting fumes on exposure and short-term lung function changes in tunnel construction workers

OBJECTIVES

This study attempts to determine the effects of exposure to blasting fumes and its influence on the lung function of tunnel workers.

METHODS

Two groups of tunnel workers, one using ammonium nitrate fuel oil (ANFO) as the explosive and the other using size-sensitized emulsion (SSE), with 24 workers per group, were compared with a reference group (N=34) with low exposure. Spirometry was used to determine lung function. Personal exposure to total and respirable dust, alpha-quartz, volatile organic compounds, oil mist and vapors, formaldehyde, nitrogen dioxide, and carbon monoxide was measured.

RESULTS

The ANFO workers were more exposed to all the agents than the reference group and more exposed than the SSE workers to all the agents except total dust and carbon monoxide. The SSE workers were significantly more exposed to total dust and alpha-quartz than the reference group. High peak exposures to nitrogen dioxide (up to 20 ppm) occurred for the ANFO workers in contrast to the SSE workers, whose exposure did not exceed 2 ppm. The lung function of the ANFO workers significantly decreased by 3% for forced vital capacity, 7% for forced expiratory volume in 1 second, and 8% for forced expiratory flow rate from 25% to 75% of the forced vital capacity over the 11-day period. The changes were reversible. There were no significant changes among the SSE workers and the outdoor workers. The ANFO workers had a significant decrease in FEV1.0 when compared with both the SSE and outdoor workers.

CONCLUSIONS

Tunnel workers using ANFO explosive show a temporary reduction in lung function, whereas those using SSE do not. The most likely explanation for the observed changes is peak exposures to nitrogen dioxide.

Late medical complications and fatigue in Hodgkin's disease survivors

PURPOSE

Long-term medical complications, such as cardiac, pulmonary, and thyroid dysfunction, are frequent among Hodgkin's disease survivors (HDSs). Chronic fatigue is also highly prevalent among HDSs. Few studies have explored possible etiologic explanations for fatigue. The aim of this study was to explore whether late cardiac, pulmonary, and thyroid complications after curative treatment for Hodgkin's disease (HD) may explain the high level of fatigue among HDSs.

PATIENTS AND METHODS

Four-hundred fifty-nine patients treated for HD at the Norwegian Radium Hospital from 1971 to 1991 were included in a cross-sectional, follow-up study of subjective health status. Fatigue (physical [PF] and mental), was measured by the Fatigue Questionnaire. A subcohort of the HDSs (116 patients) treated from 1980 to 1988 were included in a separate study in which long-term cardiac, pulmonary, and thyroid complications were assessed. All patients had received radiotherapy, and 63 patients had received additional chemotherapy. The present study comprised 92 patients (mean age, 37 years; range, 23 to 56 years) who participated in both studies.

RESULTS

HDSs with pulmonary dysfunction were more fatigued than HDSs with normal pulmonary function (PF 10.9 v 8.9; P <.05). Gas transfer impairment was the most prevalent pulmonary dysfunction, and three times as many patients with gas transfer impairment reported chronic fatigue (duration, 6 months or longer), compared with patients without pulmonary dysfunction (48% v 17%, P <.01). No associations were found between cardiac sequelae or hypothyroidism and fatigue.

CONCLUSION

Pulmonary dysfunction is associated with fatigue in HDSs. Cardiac sequelae was not associated with fatigue in HDSs. We question the absence of an association between thyroid complications and fatigue.

Gas and dust exposure in underground construction is associated with signs of airway inflammation

Exposure to gases and dust may induce airway inflammation. It was hypothesized that heavy construction workers who had been exposed to dust and gases in underground construction work for 1 yr, would have early signs of upper and lower airway inflammation, as compared to outdoor workers. A study group comprising 29 nonsmoking underground concrete workers (mean +/- SD age 44+/-12 yrs), and a reference group of 26 outdoor concrete workers (39+/-12 yrs) were examined by acoustic rhinometry, nasal and exhaled nitric oxide spirometry and a questionnaire on respiratory symptoms. Exposure measurements were carried out. The underground workers had higher exposure to total and respirable dust, alpha-quartz and nitrogen dioxide than the references (p<0.001). The occurrence of respiratory symptoms was higher in the underground workers than in the references (p<0.05). Exhaled nitric oxide (NO) (geometric mean+/-SEM) was higher in the underground workers than in the references (8.4+/-1.09 versus 5.6+/-1.07 parts per billion (ppb), p = 0.001), whereas spirometric values were comparable. The underground workers had smaller nasal cross-sectional area and volume than the references, and more pronounced increases after decongestion (p<0.001). To conclude the exposure in underground construction may cause nasal mucosal swelling and increased levels of exhaled nitric oxide, indicating signs of upper and lower airway inflammation.

Health-related quality of life in lung transplant candidates and recipients

BACKGROUND

Studies on the health-related quality of life in lung transplantation have used general questionnaires, although lung-specific instruments might be more sensitive to small differences.

OBJECTIVES

To compare the health-related quality of life of lung transplant recipients with lung transplant candidates, using lung-specific and general instruments, and to assess the reliability and validity of these questionnaires.

METHODS

The study is a cross-sectional postal survey of 31 lung transplant recipients and 15 candidates, using the following outcome measures: St. George's Respiratory Questionnaire (SGRQ), a lung-specific health status instrument; the Short Form 36 (SF-36), a general measure, and the Hospital Anxiety and Depression scale (HAD).

RESULTS

The SGRQ showed a significantly better score (p < 0.05) for transplant recipients in the impacts and activity dimensions and the total score than for candidates. SF-36 scores showed a similar improvement in all subscales of the SF-36 except bodily pain. Cronbach's alpha for all dimensions of the SGRQ, SF-36, and HAD were 0.77-0.95.

CONCLUSIONS

Patients surviving lung transplantations can expect a considerable improvement in most dimensions of health-related quality of life. This finding was consistent using both lung-specific and general measures. The reliability of the questionnaires was acceptable. The associations between scales support the validity of the questionnaires in this setting.

Increased nitric oxide in exhaled air: an early marker of asthma in non-smoking aluminium potroom workers?

OBJECTIVES

To study exhaled nitric oxide (NO) as a marker of airway inflammation caused by potroom exposure, hypothesising that (a) workers exposed to potroom pollutants would have higher concentrations of NO in expired air than control subjects employed at the same plant but working outside of the potroom atmosphere, and (b) that concentrations of exhaled NO in potroom employees might be positively associated with concentrations of fluoride and exposure to dust.

METHODS

A study group comprising 186 male subjects (aged 24-63 years), employed in the potrooms of one Norwegian aluminium smelter, and 40 comparable control subjects (aged 25-60 years) recruited from the same plant, were examined by measurements of exhaled and nasal concentrations of NO, spirometry, and a questionnaire on respiratory symptoms as a part of an annual health surveillance programme. Estimates of exposure to fluorides and dust for selected job categories were obtained by means of personal samplers carried by the workers.

RESULTS

In the non-smokers, the concentrations of exhaled NO were higher in the potroom workers than in the controls (median (interquartile range) 9.3 (6.2-15.6) v 5.7 (4.6-8.3) ppb, p=0.001). The two groups did not differ in spirometry and asthma-like symptoms. Non-smoking potroom workers with asthma-like symptoms had higher concentrations of exhaled NO than those with no symptoms (median (interquartile range) 21.0 (19.3-41. 4) v 8.5 (5.9-12.8) ppb, p=0.001), but had comparable spirometric values. In subjects who smoked, the concentrations of exhaled NO did not differ significantly between potroom workers and controls (median (interquartile range) 4.6 (3.3-8.0) v 4.0 (3.4-5.1) ppb. Exhaled NO was not significantly associated with either duration of employment or routine measurements of dust and fluorides.

CONCLUSIONS

Exposure to potroom pollutants is associated with increased concentrations of exhaled NO in non-smoking subjects. Nitric oxide in exhaled air may be an early marker of airway inflammation in aluminium potroom workers.

Increased risk of obstructive pulmonary disease in tunnel workers

BACKGROUND

Tunnel workers are exposed to gases and particles from blasting and diesel exhausts. The aim of this study was to assess the occurrence of respiratory symptoms and airflow limitation in tunnel workers and to relate these findings to years of exposure.

METHODS

Two hundred and twelve tunnel workers and a reference group of 205 other heavy construction workers participated in a cross sectional investigation. Exposure measurements were carried out to demonstrate the difference in exposure between the two occupational groups. Spirometric tests and a questionnaire on respiratory symptoms and smoking habits were applied. Atopy was determined by a multiple radioallergosorbent test (RAST). Radiological signs of silicosis were evaluated. Respiratory symptoms and lung function were studied in relation to years of exposure and adjusted for smoking habits and atopy.

RESULTS

Compared with the reference subjects the tunnel workers had a significant decrease in forced vital capacity (FVC) % predicted and forced expiratory volume in one second (FEV(1)) % predicted when related to years of exposure. Adjusted FEV(1) decreased by 17 ml for each year of tunnel work exposure compared with 0.5 ml in outdoor heavy construction workers. The tunnel workers also reported significantly higher occurrence of respiratory symptoms. The prevalence of chronic obstructive pulmonary disease (COPD) was 14% in the tunnel workers compared with 8% in the reference subjects.

CONCLUSION

Exposure to dust and gases from diesel exhaust, blasting, drilling and rock transport in tunnel work enhances the risk for accelerated decline in FEV(1), respiratory symptoms, and COPD in tunnel workers compared with other heavy construction workers.

Late medical sequelae after therapy for supradiaphragmatic Hodgkin's disease

A total of 221 consecutive early stage Hodgkin's disease (HD) patients were given mantle field irradiation only or in combination with chemotherapy in 1971-1991. In 1994 these patients responded to a mailed self-report questionnaire covering items on late medical symptoms. Of 200 patients (91%) who reported that their thyroid function had been tested, 110 patients (55% of those tested) had thyroid hypofunction at follow-up in 1994. Ninety-five patients (86% of patients with biochemical hypothyreosis) had started hormonal substitution. In 1993 and 1994, 101 of these patients who had received mantle field irradiation in 1980-1988 were called in for interview, clinical examination and thyroid function tests. Eighteen patients (18%) had started hormonal substitution treatment earlier, but 58 (70%) of the other 83 patients were found to have biochemical hypothyreosis. Of the 221 patients who completed the questionnaire, 66 patients (30%) reported dyspnoea on exertion for more than 3 years after treatment, 8 patients (4%) reported a history of myocardial infarction, 6 patients (3%) reported pericardial disease and 25 patients (11%) heart valve disease. Increased expenses incurred for dental care were reported by 106 patients (48%), increasing to 55% when Waldeyer's ring had been irradiated. The consequences of late sequelae after mantle field irradiation for future treatment are discussed.

[Late complications after treatment of Hodgkin's disease]

Treatment of Hodgkin's disease involves chemotherapy and radiation. Both modalities may cause cardiac, pulmonary and thyroid side-effects. In a cross-sectional study, we aimed to assess the occurrence and severity of such complications. From 1980 to 1989, 129 Norwegian patients (< 50 years old) had curative treatment for Hodgkin's disease 116 (90%) of them participated in the study (follow-up period 5-13 years). Methods included lung function tests, chest X-rays, bicycle exercise tests, echocardiography and thyroid function tests. Nearly 30% of the patients reported dyspnoea on exertion and had associated reductions in lung function. Evidence of fibrosis occurred in 68%, but was associated with reduced lung function in only 12%. Pathological left-sided heart valve regurgitations were detected in 24% of the patients, pericardial thickening in 15%, and coronary artery disease in 5%. Biochemical hypothyreosis was found in 67% of the patients. We conclude that cardiac, pulmonary and thyroid dysfunctions are frequent long-term side-effects after treatment for Hodgkin's disease. We recommend annual screening of thyroid function and echocardiographic examination in patients who have received standard mantle field radiotherapy without cardiac shielding. Lung function testing should be done in individuals who require further radiation, chemotherapy or thoracic surgery.

[Measurement of exhaled nitric oxide. A new lung function test?]

Nitric oxide (NO) is a gas molecule produced endogenously in the lungs. It can be detected in the exhaled air of animals and humans. Nitric oxide can be generated in the air passages by a synthase which is induced in several cell types by exposure to proinflammatory cytokines. Its induction is blocked by glucocorticoids. An increased concentration of nitric oxide can be found in the exhaled air of patients with asthma and other inflammatory lung disorders. Gas analysers for measuring nitric oxide in exhaled air have recently been made commercially available. The test is non-invasive, simple to perform, and can also be used in patients with reduced lung function. The method seems to provide a unique non-invasive means of diagnosing and monitoring inflammation of the air passages, and in the future the test may become a useful tool in a clinical setting. Preliminary recommendations for measurements and technical standardization have recently been proposed by the European Respiratory Society.

Increased risk of heart valve regurgitation after mediastinal radiation for Hodgkin's disease: an echocardiographic study

OBJECTIVE

To assess by echocardiography the occurrence and degree of late cardiac sequelae after treatment for Hodgkin's disease by radiation and chemotherapy.

PATIENTS AND METHODS

In Norway from 1980 to 1988, 129 patients < 50 years old with Hodgkin's disease had curative treatment with mediastinal radiation, with or without chemotherapy. 116 (90%) of these patients (mean (SD) age 37 (7) years, 67 males) were examined by echocardiography 5-13 years after treatment. 40 healthy individuals (mean (SD) age 40 (11), 20 males) were examined as controls. All those examined were in regular sinus rhythm.

RESULTS

Grade > 1 (scale 0-3) aortic and/or mitral valvar regurgitation was found in 24% of the patients (15% aortic, 7% mitral, and 2% aortic+mitral), affecting 46% of the females v 16% of the males (P < 0.001). Female gender was a significant risk factor for aortic and mitral regurgitation (odds ratio 4.7, 95% confidence interval 2.0 to 11.2), whereas age, period of follow up, radiation dose, and chemotherapy were not. Thickened pericardium was diagnosed in 15% of the patients. No risk factors were identified. No cases of pericardial thickening or valvar regurgitation grade > 1 were recorded in the control group. Mean values for measured and calculated indices of systolic and diastolic function were within the normal range for patients and controls. The patients had reduced E/A ratio compared with the healthy controls (E/A 1.1 v 2.0, P < 0.001).

CONCLUSIONS

Abnormal left sided valvar regurgitation was detected in one fourth of the patients, affecting the aortic valve in more than half of the cases. Females had an increased risk of valvar regurgitation. Echocardiographic screening after high-dose mediastinal radiation is recommended.

Cardiopulmonary sequelae after treatment for Hodgkin's disease: increased risk in females?

BACKGROUND

The treatment of Hodgkin's disease (HD) involves irradiation and chemotherapy. Both modalities may cause heart and lung injury. We aimed to assess 1) the occurrence of such injury, 2) the extent to which combined versus single-organ-affection resulted in disability, and 3) whether determinants for cardiopulmonary injury could be identified.

PATIENTS AND METHODS

A national cohort (n = 116) of HD patients (mean age 37 +/- 7 (SD) years, 67 males) was examined by interview, echocardiography, bicycle exercise test and lung function tests, 5-13 years after mediastinal irradiation with or without chemotherapy.

RESULTS

Cardiac, pulmonary or combined sequelae occurred, respectively, in 21%, 15% and 19% of the patients affecting 75% of the females versus 41% of the males (P < 0.001). Of the patients with combined sequelae, 27% were disabled versus 4% of the rest (P < 0.05). Combined sequelae was associated with dyspnoea (P < 0.001) and reduced maximal exercise heart rate (P < 0.05). Compared to males, females had an increased risk of heart valve regurgitation (46% versus 16%, P < 0.001), pericardial thickening (22% versus 10%, P = 0.07) and reduced gas transfer (41% versus 22%, P = 0.03). Female gender was a significant risk factor for cardiac and/or pulmonary sequelae (OR 6.1, 95% CI 2.4-15.7), whereas age, follow-up period, smoking habits, histology, bulky mediastinal disease, radiation dose and chemotherapy were not. Mean exercise work capacity and O2-saturation were within normal limits.

CONCLUSIONS

Although cardiac and/or pulmonary sequelae were detected in more than half of the patients, only combined injury was associated with disability, dyspnoea and reduced performance. Females had an increased risk of cardiopulmonary sequelae, which could not be explained by treatment-related differences between the genders.

Decreased lung function in one year survivors of allogeneic bone marrow transplantation conditioned with high-dose busulphan and cyclophosphamide

Conditioning with busulphan (BU) and cyclophosphamide (CY) prior to allogeneic bone marrow transplantation (BMT) is an alternative to regimens that include total body irradiation (TBI). The aim of the study was to assess the occurrence and degree of lung function impairment after this treatment. Prospectively, 43 consecutive patients, aged 17-51 (median 31) yrs, were examined by lung function measurements and clinical and radiographic evaluation, prior to BMT and at 3 month intervals up to 1 yr after BMT. All patients had normal chest radiographs before BMT and at the 12 month follow-up. Mean baseline values were above 100% of predicted normal for lung volumes and above 90% for gas transfer. Excluded from the lung function follow-up analyses were nine patients who had suffered infectious pneumonia and/or developed obliterative bronchiolitis. For the remaining patients (n = 34), mean alveolar volume (VA), forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) had dropped by nearly 10% compared with baseline 3 months after BMT, but were restored within 1 yr. FEV1/FVC x 100 (FEV1%) was increased, reflecting the restrictive pattern. Hb-adjusted transfer factor of the lungs for carbon monoxide (TL,CO) had dropped by 20% after 3 months, and remained reduced by 15% after 1 year. Prior to BMT the smokers had significantly lower TL,CO than the nonsmokers, and after BMT the difference was accentuated. Reductions in lung function were independent of sex, age and type of haematological disorder. We conclude that BMT with BU/CY is associated with transient declines in lung volumes and a persistent reduction in gas transfer 1 yr after therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Lung function impairment in long-term survivors of Hodgkin's disease

BACKGROUND

Treatment of Hodgkin's disease (HD) involves radiation and chemotherapy, modalities known to cause lung injury.

PATIENTS AND METHODS

In Norway, between 1980 and 1988, 129 patients aged less than 50 years at the time of diagnosis, had curative treatment with thoracic radiation alone or combined-modality therapy for supradiaphragmatic HD. We have examined 116 (90%) of these patients by interview, chest X-ray and lung function tests, 5-13 years after treatment.

RESULTS

Nearly 30% of the patients had dyspnoea on exertion and associated reductions in total lung capacity (TLC), forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1) and gas transfer (TLCO) (p < 0.05). Radiographic evidence of no, slight or moderate fibrosis occurred in 32%, 54% and 14% of the patients, respectively. Moderate fibrosis was associated with reductions in FVC, FEV1 and TLCO (p < 0.05). Radiation plus chemotherapy containing bleomycin-anthracyclines (median cumulative bleomycin dose 120 mg) was associated with decreases in FVC and TLCO (p < 0.05). In the multivariate analysis, chemotherapy with bleomycin-anthracyclines was the only significant predictor for lung function impairment.

CONCLUSION

More than five years after therapy, respiratory symptoms and reduction in lung function were diagnosed in nearly one-third of otherwise healthy HD survivors.

[Mortality in operable lung cancer]

We have retrospectively examined the medical records and prospectively studied the survival of the 50 men and 26 women who underwent surgery for primary non-small cell lung cancer at our hospital during the period 1982 to 1986. Adenocarcinoma was the predominant histologic type of tumour (55%). Pneumonectomy was performed in only 17% of the cases. Surgery was considered to be radical in 54 patients. This was not dependent on sex, histology or type of resection. 60% of the patients were alive after three years. Almost all of them had undergone radical resection. The surviving patients (at follow-up 1 July, 1990) had been younger at the time of surgery and had a lower erythrocyte sedimentation rate than those who had died. As a group, however, they had not lived longer than those who died.

[Gastrointestinal cytomegalovirus infection in patients with heart transplants]

Cytomegalovirus (CMV) infection is a major cause of morbidity in organ transplant recipients. Gastrointestinal CMV disease is a serious and potentially lethal complication requiring treatment with antiviral agents. The symptoms and endoscopic findings are nonspecific. The diagnosis may be decided by histological examination, since CMV inclusions can be verified immunohistochemically in routine sections. In a series of 132 heart transplant recipients, 26 developed CMV-infection. Three of these patients had serious gastrointestinal disease. This report describes the patients with gastrointestinal CMV infection, and briefly discusses symptomatology, diagnostic considerations and suggested treatment.

The effect on pulmonary function of tangential field technique in radiotherapy for carcinoma of the breast

Twenty-five patients treated by lumpectomy and radiotherapy for Stage I breast cancer were enrolled in a prospective study to measure the effects of tangential field irradiation on pulmonary function. Fractional doses of 2 Gy to a total of 50 Gy were administered with the tangential technique. An additional 10 Gy (2 Gy x 5) was given as direct booster. Dynamic and static lung volumes, distribution of ventilation and gas transfer were measured before irradiation and at varying intervals up to 1 year after the completion of therapy. There was a small, but statistically significant decrease in the forced vital capacity (mean 63 ml) and the forced expiratory volume in 1 second (mean 79 ml) measured 3 months after irradiation (p less than 0.05). These changes were reversed within 1 year. The reduction in total lung capacity (mean 240 ml) after 3 months was nearly significant (p = 0.06). The remaining variables did not change to a significant degree. We conclude that a slight restrictive ventilatory impairment may occur when a combined tangential and direct booster technique is applied. The changes are, however, small and reversible, and imply no clinical importance.

[Combined lung and heart surgery]

Patients with concomitant pulmonary carcinoma and serious heart disease represent a therapeutic challenge. With the introduction of combined lung-heart surgery, both conditions may be treated adequately and safely. At Rikshospitalet, combined surgery was performed in four cases during the period 1984-88. In three patients heart surgery and lung resection were performed in one anesthetic session. In the fourth case the heart disease was corrected first and the tumor removed a few weeks later. After 1-4 years follow-up none of the patients has clinical manifestations of either condition. Combined surgery is only applicable if tumor removal is confined to wedge resection or lobectomy.