Biomedical subjects

A U Wells

Publications and source records attributed to A U Wells.

At least 55 records · Page 3Linked to original sources

PubMed2001

Cryptogenic organizing pneumonia.

The terms cryptogenic organizing pneumonia (COP) and idiopathic bronchiolitis obliterans with organizing pneumonia (BOOP) are synonymous. Typical COP should be viewed as a clinicopathological syndrome, consisting of respiratory and systemic symptoms (usually low-grade), patchy consolidation on chest radiography and computed tomography, a restrictive defect on pulmonary function testing, and the presence of buds of granulation tissue within the distal airways and alveolar spaces. In the correct clinical context, the diagnosis can be secured by transbronchial biopsy, with typical bronchoalveolar lavage features providing useful diagnostic support. In typical COP, corticosteroid therapy is highly effective; an early trial of withdrawal of treatment is appropriate because relapse of COP is not associated with a poor long-term outcome. Atypical forms of COP are outlined in this article, including focal, explosive, progressive fibrotic, and nonprogressive fibrotic variants. The occasional evolution of COP into a progressive fibrotic disorder is associated with a poor long-term outcome and poses particular therapeutic difficulties.

Journal Article↗

PubMed2001

Lung fibrosis: new classifications and therapy.

The recent American Thoracic Society/European Respiratory Society consensus classification of idiopathic interstitial pneumonia is equally applicable to pulmonary fibrosis associated with connective tissue disease. The most frequent histopathologic entities are usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP), which is more prevalent than UIP in systemic sclerosis. The prognostic significance of NSIP is unknown in connective tissue disease, although NSIP has a better prognosis than UIP in idiopathic interstitial pneumonia. The use of computed tomography to distinguish between UIP and NSIP requires further refinement. Recent therapeutic studies have reinforced disenchantment amongst clinicians with corticosteroid and immunosuppressive regimens in UIP. UIP is increasingly regarded an "epithelial-fibrotic" disease rather than a primarily inflammatory disorder, accounting for recent widespread interest in antifibrotic agents. This conclusion should not be extrapolated to NSIP, especially in connective tissue disease. Strong circumstantial evidence of a therapeutic benefit justifies the continued use of cyclophosphamide in progressive lung fibrosis in systemic sclerosis.

Connective Tissue Diseases↗

PubMed2001

Nonspecific interstitial pneumonia and usual interstitial pneumonia: comparative appearances at and diagnostic accuracy of thin-section CT.

PURPOSE: To compare the morphologic abnormalities on thin-section computed tomographic (CT) images in a group of patients with histopathologically confirmed nonspecific interstitial pneumonia (NSIP) or usual interstitial pneumonia (UIP) and a clinical presentation of idiopathic pulmonary fibrosis. MATERIALS AND METHODS: Thin-section CT imaging patterns and distribution of disease in 53 patients with histologic diagnoses of NSIP (n = 21) or UIP (n = 32) were quantified retrospectively and independently by four observers. The appearances of NSIP and UIP at CT were compared with univariate and multivariate techniques. RESULTS: The use of thin-section CT proved to have moderate sensitivity (70%), specificity (63%), and accuracy (66%) in the diagnosis of NSIP. An increased proportion of ground-glass attenuation was the cardinal feature of NSIP at CT (odds ratio: 1.04 for each 1% increase in the proportion of ground-glass attenuation). A histologic diagnosis of NSIP was most frequent (in 24 of 35 observations [69%]) when ground-glass attenuation predominated, and was more frequent with mixed (35 of 79 observations [44%]) than with predominantly reticular disease (25 of 98 [26%] observations, P < .005). Logistic regression analysis of the data indicated that misdiagnosis of UIP in patients with NSIP was associated with less ground-glass attenuation (P < .005) at CT and a subpleural disease distribution (P = .02), with the converse being true for UIP cases misdiagnosed as NSIP. CONCLUSION: In patients with a clinical presentation of idiopathic pulmonary fibrosis, the accuracy of thin-section CT in identifying NSIP is considerably higher than previously reported. At CT, NSIP is characterized by more ground-glass attenuation and a finer reticular pattern than is UIP. Nevertheless, considerable overlap in thin-section CT patterns exists between NSIP and UIP.

Biopsy↗

PubMed2001

Acute respiratory distress syndrome caused by pulmonary and extrapulmonary injury: a comparative CT study.

PURPOSE: To determine computed tomographic (CT) differences between acute respiratory distress syndrome (ARDS) due to pulmonary injury (ARDS(p)) and extrapulmonary injury (ARDS(ex)). MATERIALS AND METHODS: CT appearances in 41 patients (27 male, 14 female; mean age, 47.1 years +/- 17.1 [SD]; age range, 17-79 years; those with ARDS(p), n = 16; those with ARDS(ex), n = 25) were categorized as typical or atypical of ARDS by two observers. The extent of individual CT patterns was also quantified. RESULTS: Typical CT appearances were more frequent in ARDS(ex) than ARDS(p) (18 [72%] of 25 vs five [31%] of 16 patients, respectively; P <.01). Sensitivity, specificity, and accuracy of a typical CT pattern for the diagnosis of ARDS(ex) were 72%, 69%, and 71%, respectively. Atypical appearances were characterized by more extensive nondependent intense parenchymal opacification (IPO) (P =.03) and cysts (P =.05), whereas typical CT appearances had more extensive dependent IPO (P =.01). Typical appearances at CT were independently related to the cause of ARDS (odds ratio, 8.9; 95% CI: 1.8, 44.2; P <.01) but were independent of the time from intubation. Foci of nondependent IPO were more extensive in ARDS(p) (P =.05) than ARDS(ex), but this finding was ascribable to differences in time to CT (after intubation) between ARDS(p) and ARDS(ex). CONCLUSION: The differentiation between ARDS(p) and ARDS(ex) can, with some caveats, be based on whether the CT appearances are typical or atypical of ARDS but not on any individual CT pattern in isolation.

Adolescent↗

PubMed2001

Functional consequences of pleural disease evaluated with chest radiography and CT.

PURPOSE: To identify a system for the quantification of pleural thickening with an acceptable level of interobserver variation and good functional correlation in individuals with pleural disease. MATERIALS AND METHODS: The extent of pleural thickening and plaques was assessed in 50 patients by using the following: (a) a radiographic score based on the International Labour Office system, (b) a subjective simple computed tomographic (CT) score, (c) a subjective comprehensive CT score, (d) an objective nonautomated method, and (e) an objective computer-aided semiautomated method. RESULTS: Similar correlations between the extent of diffuse pleural thickening and forced vital capacity were seen for each system (objective CT, r = -0.72, P <.001; simple CT, r = -0.69, P <.001; radiographic, r = -0.67, P <.001; comprehensive CT, r = -0.66, P <.001). Comparable correlations were observed for total lung capacity. After controlling for extent of diffuse pleural thickening, pleural plaque scores were functionally irrelevant. CONCLUSION: Comparable functional-morphologic correlations were achieved by using different CT and radiographic scoring systems for pleural disease. A subjective simple CT system had the advantages of ease of application and potential to aid in the accurate assessment of the lung parenchyma, which may be important in individuals exposed to asbestos.

Adult↗

PubMed2001

Analysis of tumor necrosis factor-alpha, lymphotoxin-alpha, tumor necrosis factor receptor II, and interleukin-6 polymorphisms in patients with idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is characterized by chronic inflammation that is associated with structural damage of the lung and fibrosis. Although the etiology of IPF is unknown, it is likely to involve an interaction between environmental and multiple genetic components. Animal models of pulmonary fibrosis have shown that proinflammatory mediators are critical at both the inflammatory and fibrotic stages of the disease. Genetic variants exist in genes encoding proinflammatory mediators, as well as in genes encoding their receptors, which makes these genes candidates for the pathogenesis of IPF. In the present study, we examined 12 biallelic polymorphisms in the genes for tumor necrosis factor (TNF)-alpha (+488[G/A], -238[G/A], -308[G/A]), lymphotoxin (LT)-alpha (+720[C/A], +365[C/G], and +249[A/G], determining haplotypes LT-alpha1 to LT-alpha4), tumor necrosis factor-receptor 2 (TNF-RII) (gb:M32315: 676[T/G], 1663[A/G], 1668[T/G], 1690[C/T]), and interleukin- (IL)-6 (promoter -174[G/C], intron 4[A/G]). We also examined the haplotypes determined by the three biallelic polymorphisms in each of the TNF-alpha and LT-alpha genes. As compared with a normal control population, the IPF group showed no significant deviations in genotype, allele, or haplotype frequencies. Surprisingly, in the IPF population, but not in the control population, an increased frequency of cocarriage of the IL-6 intron 4G and the TNF-RII 1690C alleles was observed, despite the location of the two genes on different chromosomes. Moreover, using impairment of carbon monoxide transfer (DL(CO)) adjusted for duration of dyspnea as a marker of rapidity of disease progression, we found that the IL-6 intron 4GG genotype was the only genotype independently associated with lower DL(CO) levels. These findings, if independently confirmed, will be the first to suggest that disease progression in IPF may be linked to a particular genetic marker or to functional polymorphisms in other genes near that marker.

Antigens, CD↗

PubMed2001

Lung biopsy in diffuse parenchymal lung disease.

This review sets out to define the role of surgical biopsy in the diagnosis and prognosis of diffuse parenchymal lung disease, the pros and cons of each procedure and the interpretation of the results in the context of clinical and other investigative data. Surgical lung biopsy remains the investigation with the greatest overall diagnostic sensitivity for diffuse parenchymal lung disease. Rates of diagnosis are approximately 90-95%, compared with approximately 70% for both high-resolution computed tomography (HRCT) and transbronchial biopsy. Although open lung biopsy, and more recently videoassisted thoracoscopic surgery, have good safety records, neither technique has been utilised as frequently as might be expected, with wide regional variation for various reasons. More recently, HRCT used in conjunction with clinical and other investigative modalities, has increased the accuracy of diagnosis for some diseases, including the majority of cases of cryptogenic fibrosing alveolitis (HRCT & bronchoalveolar lavage), Langerhans' cell histiocytosis (HRCT), lymphangioleiomyomatosis (HRCT), and silicosis (HRCT). At present, the vasculitides and the idiopathic interstitial pneumonias, other than cryptogenic fibrosing alveolitis, always require a surgical biopsy. As experience with high resolution computed tomography grows, it is possible that other diseases will be able to be diagnosed without surgical biopsy. These newer modalities of investigation do have appreciable limitations and where sufficient doubt exists about diagnosis, surgical lung biopsy must continue to be utilised.

Biopsy, Needle↗

PubMed2001

The application of high-resolution CT to diagnosis in diffuse parenchymal lung disease.

High resolution computed tomography (CT) now has a central role in the evaluation of diffuse lung disease. It is of particular use in the formulation of a differential diagnosis. Whilst CT often conveys sufficient information to allow non-invasive diagnosis, it sometimes reveals atypical appearances, contributing to the continuing reclassification of diffuse lung disease and justifying histological evaluation in some patients. Thus, CT as a new technology does not always replace conventional diagnostic methods, but is best integrated with clinical assessment, other non-invasive investigations and surgical lung biopsy: this applies equally to clinical diagnosis and to the definition and reclassification of disease entities. In this article, we explore the optimal diagnostic use of CT. The limitations of CT series in simulating the clinical application of CT in the management of diffuse parenchymal lung disease highlight the need for an integrated approach to diagnosis, including corroborative data drawn from many sources. High-resolution computed tomography, when interpreted in the context of the pre-test probability, obviates invasive investigation in many cases. As descriptions of the CT appearances of individual diffuse lung diseases are refined, ongoing re-evaluation is required to establish which features can be regarded as pathognomonic, for diagnostic purposes, and how CT can be integrated into revised disease definitions so that the most clinically relevant diagnostic criteria are formulated.

Female↗

PubMed2001

Interstitial lung diseases: an epidemiological overview.

Epidemiological studies on interstitial lung diseases (ILDs) may be schematically subdivided into the following major types: 1) quantifications of disease, broken down into incidence, prevalence and mortality data; 2) identification of aetiological factors; and 3) clinical epidemiological studies. Epidemiological data may be obtained from different sources or population groups, using different study designs such as systematic national statistics, population-based data and registries, and large case series of specific diseases. Differences in results between epidemiological studies may be due to real differences in incidence, but may also be due to changes in disease definitions and classifications, differences in the epidemiological design of the studies, or even registration bias. Comparative epidemiological data of different ILDs are almost limited to the general population study in Bernalillo County and to national mortality statistics, which should be interpreted with great caution. Also, some, mostly national registries of the different ILDs have been carried out by specific medical profession groups (especially pulmonologists), which clearly underestimate the real incidence of ILDs, but in which the comparison of the relative frequencies is probably accurate. Based on all these comparative studies, sarcoidosis and idiopathic pulmonary fibrosis appear to be the most frequent ILDs, followed by hypersensitivity pneumonitis and ILD in collagen vascular disease, when classical pneumoconioses are not included. There is also a relatively large group of nonspecific fibrosis. Much more data have been published on the epidemiology of specific forms of interstitial lung disease. Most information is available on the epidemiology of sarcoidosis, and those data are probably the most accurate. Data on idiopathic pulmonary fibrosis have the disadvantage of the recent changes in definition and classification of this disease. Hypersensitivity pneumonitis has been studied epidemiologically, especially in some exposure groups such as farmers and pigeon breeders, and in some regions in North America, UK, France and Scandinavia. Estimates of frequencies of interstitial lung disease in collagen vascular disease or of drug-induced interstitial lung disease are less accurate and more variable, depending on diagnostic criteria. Notwithstanding the aforementioned problems, this report tries to provide a balanced overview of the epidemiology of different interstitial lung diseases.

Humans↗

PubMed2001

Cryptogenic fibrosing alveolitis/idiopathic pulmonary fibrosis.

Cryptogenic fibrosing alveolitis (CFA), synonymous with idiopathic pulmonary fibrosis (IPF), remains a life-threatening disease: 50% of patients die within 5 yrs. Historically, many diseases that are now considered to be quite distinct have been "labelled" as CFA. More recently, high-resolution computed tomography and new appreciation of the histopathological patterns of idiopathic interstitial pneumonias have enabled disease variants to be defined according to their different responses to therapy and survival. CFA is believed to be induced by an external agent, although it is not clear whether CFA represents the final common outcome of numerous pathogenetic mechanisms or has a single cause. In addition, there are currently no prospective double-blind, placebo-controlled trials of treatment showing superiority of one drug regimen over another. This review attempts to dissect the different patterns of cryptogenic fibrosing alveolitis, illustrate the major features of each, and refine the clinico-radiological-pathological descriptors that together define cryptogenic fibrosing alveolitis as it is understood today.

Humans↗

PubMed2000

Lateral cavity wall thickening as an early radiographic sign of mycetoma formation.

The sensitivity of chest radiography for the early detection of mycetoma formation within fibrotic cavities is poor. The purpose of this study was to determine the predictive value of the secondary sign of lateral cavity wall thickening for the detection of a radiographically occult mycetoma. The chest radiographs and CT scans of 70 patients who had a total of 109 fibrotic cavities on CT were reviewed by two observers. Dimensions of the cavity, mycetoma, and cavity wall thickness on chest radiography and CT scans were recorded. Mycetomas were visible in 41 of 99 cavities on chest radiographs and in 61 of 109 cavities on CT. Using CT as the gold standard for detecting the presence of mycetomas, the sensitivity of chest radiography for the presence of a mycetoma was 62 % and the specificity 94 %, and the positive and negative predictive values were 93 and 66 %, respectively. On logistic regression analysis, lateral wall thickness on chest radiography was predictive of the presence of a mycetoma (p < 0.0005) independent of other radiographic features. In patients with chronic fibrocavitary disease on chest radiography, the presence of lateral wall thickening is highly suggestive of an underlying mycetoma.

Aspergillosis↗

PubMed2000

Evaluation of patients undergoing lung volume reduction surgery: ancillary information available from computed tomography.

AIM: A number of imaging techniques have been used for the pre-operative assessment of patients for lung volume reduction surgery (LVRS). We evaluated whether data currently acquired from perfusion scintigrams and cine MR of the diaphragm are obtainable from high resolution CT (HRCT) of the thorax. MATERIALS AND METHODS: Thirty patients taking part in a randomized controlled trial of LVRS against maximal medical therapy were evaluated. HRCT examinations (n= 30) were scored for (i) the extent and distribution of emphysema; (ii) the extent of normal pulmonary vasculature; and (iii) diaphragmatic contour, apparent defects and herniation. On scintigraphy, (n= 28), perfusion of the lower thirds of both lungs, as a proportion of total lung perfusion (LZ/T(PERF)), was expressed as a percentage of predicted values (derived from 10 normal control subjects). On cine MR (n= 25) hemidiaphragmatic excursion and coordination were recorded. RESULTS: Extensive emphysema was present on HRCT (60% +/- 13.2%). There was strong correlation between the extent of normal pulmonary vasculature on HRCT and on perfusion scanning (r(s)= 0.85, P< 0.00005). Hemidiaphragmatic incoordination on MR was weakly associated with hemidiaphragmatic eventration on HRCT (P= 0.04). CONCLUSION: The strong correlation between lung perfusion assessed by HRCT and lung perfusion on scintigraphy suggests that perfusion scintigraphy is superfluous in the pre-operative evaluation of patients with emphysema for LVRS.

Adult↗

PubMed2000

Airflow obstruction in bronchiectasis: correlation between computed tomography features and pulmonary function tests.

BACKGROUND: An obstructive defect is usual in bronchiectasis, but the pathophysiological basis of airflow obstruction remains uncertain. High resolution computed tomographic (CT) scanning now allows quantitation of static morphological abnormalities, as well as dynamic changes shown on expiratory CT scans. The aim of this study was to determine which static and dynamic structural abnormalities on the CT scan are associated with airflow obstruction in bronchiectasis. METHODS: The inspiratory and expiratory features on the CT scan of 100 patients with bronchiectasis undergoing concurrent lung function tests were scored semi-quantitatively by three observers. RESULTS: On univariate analysis the extent and severity of bronchiectasis, the severity of bronchial wall thickening, and the extent of decreased attenuation on the expiratory CT scan correlated strongly with the severity of airflow obstruction; the closest relationship was seen between decreased forced expiratory volume in one second (FEV(1)) and the extent of decreased attenuation on the expiratory CT scan (R(s) = -0.55, p<0. 00005). On multivariate analysis bronchial wall thickness and decreased attenuation were consistently the strongest independent determinants of airflow obstruction. The extent of decreased attenuation was positively associated with the severity of bronchial wall thickness, but was not independently linked to gas transfer levels. Endobronchial secretions seen on CT scanning had no functional significance; the severity of bronchial dilatation was negatively associated with airflow obstruction after adjustment for other morphological features. CONCLUSIONS: These findings indicate that airflow obstruction in bronchiectasis is primarily linked to evidence of intrinsic disease of small and medium airways on CT scanning and not to bronchiectatic abnormalities in large airways, emphysema, or retained endobronchial secretions.

Adult↗

PubMed2000

Nonspecific interstitial pneumonia: variable appearance at high-resolution chest CT.

PURPOSE: To describe the computed tomographic (CT) findings in patients with nonspecific interstitial pneumonia (NSIP) and to compare these with the CT findings of other chronic infiltrative lung diseases. MATERIALS AND METHODS: Findings in 50 patients with biopsy-proved NSIP and a CT scan were reviewed by two thoracic radiologists in consensus. After the findings were described, the observers judged whether the findings were compatible with previously published descriptions of NSIP or whether the findings would support the diagnosis of a different chronic infiltrative lung disease. RESULTS: Eleven (22%) of the 50 patients had CT findings that were compatible with previous descriptions of NSIP. Sixteen (32%) patients had CT findings that were more compatible with usual interstitial pneumonia. The other 23 (46%) patients had findings that were nondiagnostic or most compatible with the diagnosis of another chronic infiltrative lung disease. CONCLUSION: Contrary to previously published articles, there are a wide variety of CT findings in cases of NSIP.

Adult↗

PubMed2000

The prognostic significance of the histologic pattern of interstitial pneumonia in patients presenting with the clinical entity of cryptogenic fibrosing alveolitis.

Lone cryptogenic fibrosing alveolitis (CFA) is a progressive interstitial lung disease, with a median survival of 3 to 6 yr from the onset of dyspnea. CFA can be subdivided into prognostically significant histopathologic patterns, including nonspecific interstitial pneumonia (NSIP). We reviewed 78 patients with a clinicopathologic diagnosis of CFA, biopsied between 1978 and 1989, to evaluate the prevalence and prognostic significance of these histopathologic patterns, in particular NSIP. Biopsy appearances were reclassified by two pulmonary histopathologists as usual interstitial pneumonia (UIP) (47%), NSIP (36%), or desquamative interstitial pneumonia (DIP)/respiratory bronchiolitis-associated interstitial lung disease (RBILD) (17%). The kappa coefficient of agreement between pathologists was 0.49. In 67 cases, follow-up was complete to death or 10 yr after biopsy, with 50 deaths during a median follow-up of 42 mo (UIP, 89%; NSIP, 61%, DIP/RBILD, 0%). Survival was highest in DIP/RBILD and higher in NSIP than UIP, p < 0.0005. When analysis was confined to patients with UIP or NSIP, the mortality of UIP remained higher, p < 0.01, but the 5-yr survival in patients with fibrotic NSIP was only 45%, indicating that this histologic appearance is often associated with a poor outcome. A response to treatment was more frequent in DIP/RBILD than in NSIP (p < 0.01) or UIP (p < 0.0005). This study confirms the prognostic value of subclassifying patients with CFA according to histopathologic pattern. However, in patients with clinically typical CFA, a histologic diagnosis of fibrotic NSIP needs to be interpreted with caution and does not necessarily denote a good outcome.

Biopsy↗

PubMed2000

Allergic bronchopulmonary aspergillosis in the asthma clinic. A prospective evaluation of CT in the diagnostic algorithm.

OBJECTIVE: Allergic bronchopulmonary aspergillosis (ABPA) occurs in cases of atopic asthma and may result in important lung disease. Early diagnosis is essential as this disease is responsive to steroids. However, while asthma is common, ABPA is infrequently diagnosed. CT allows precision in the diagnosis of central bronchiectasis (which is virtually pathognomonic of ABPA) and may enable earlier diagnosis. DESIGN: A prospective evaluation of 255 patients with asthma for ABPA, using skin prick testing (SPT) for Aspergillus fumigatus (AF) as a screening tool and incorporating CT into the diagnostic algorithm. SETTING: Asthma clinic, Green Lane Hospital, Auckland, New Zealand. PARTICIPANTS: Patients with asthma. INTERVENTIONS: ABPA was diagnosed using "essential" criteria (ie, asthma, SPT positivity to AF, elevated serum total IgE, elevated serum AF-specific IgE, and pulmonary infiltrates seen on chest radiography or central bronchiectasis seen on CT scan) and "minimal essential" criteria (ie, asthma, SPT positivity, and central bronchiectasis). MEASUREMENTS AND RESULTS: Two hundred fifty-five consecutive patients with asthma who consented to SPT were studied: 218 of 255 patients (86.8%) were atopic; and 47 of 255 patients (21.6%) were AF-positive, of whom 35 accepted further evaluation including CT scanning. A secure diagnosis of ABPA, satisfying all essential criteria, was evident in 9 of 35 patients (25.7%), a proportion that increased to 13 of 35 patients (37.1%) by using the minimal essential diagnostic criteria. CONCLUSIONS: SPT positivity to AF was present in approximately 20% of patients in the asthma clinic. A diagnosis of ABPA is disclosed by CT in 25 to 40% of SPT-positive patients, depending on the selection of diagnostic criteria. These findings support the use of SPT as a screening tool in the asthma clinic and indicate that a routine CT scan is warranted in SPT-positive patients.

Adult↗

PubMed1999

Human in vitro immune responses to Mycobacterium tuberculosis.

SETTING: T helper cells can be divided into 2 subsets on the basis of their cytokine generation. T helper 1 cells secreting gamma interferon and interleukin 2 appear to be more prominent in patients with limited tuberculous disease. OBJECTIVE: The purpose of this study was to evaluate human T helper cell immune responses to mycobacterial antigens in vitro and correlate these with the clinical features of patients with tuberculous infection or disease. DESIGN: We studied 51 subjects and 11 controls who were grouped according to disease involvement as follows: 1) Mantoux negative, BCG negative, no disease; 2) Mantoux positive, no disease; 3) localized extrapulmonary; 4) healed pulmonary; 5) active pulmonary; and 6) miliary/disseminated. Peripheral blood mononuclear cells were cultured with PHA, PPD or Tetanus Toxoid, proliferation assessed and the supernatant analysed using an ELISA for IFN gamma. ELISA was also used to measure M. tuberculosis specific antibodies in the serum. RESULTS: Mantoux size correlated with PPD proliferation r = 0.5, P = 0.005 and gamma IFN production r = 0.36, P < 0.01. All groups produced abundant gamma IFN although there was a trend toward higher production in groups 3 and 4. M. tuberculosis specific IgA (P = 0.003) and IgG1 (P = 0.002) was higher in groups 5 and 6. Those patients with limited disease (groups 2-4) had significantly lower levels of IgG4 than patients with severe disease (groups 5 & 6) (P < 0.02). CONCLUSION: In conclusion patients with healed or extrapulmonary disease have immune responses in vitro suggestive of a TH1 (cell mediated immune) response, whereas patients with miliary/disseminated disease have antibody production suggestive of a TH2 response, together with high gamma IFN production. Both TH1 and TH2 responses may be necessary for host protection if there is a high bacillary load.

Acute Disease↗

PubMed1999

A CT sign of chronic pulmonary arterial hypertension: the ratio of main pulmonary artery to aortic diameter.

The aim of this study was to determine whether the ratio of the diameters of the main pulmonary artery and of the ascending aorta (rPA), as assessed on computed tomography (CT), is predictive of pulmonary arterial hypertension (PAH). We undertook a retrospective review of 50 patients with a wide range of pulmonary and cardiovascular diseases, who had undergone both chest CT and pulmonary arterial pressure measurements at right heart catheterization. Two independent observers made measurements of the diameter of the main pulmonary artery and of the ascending aorta on a single defined CT section. Body surface area (BSA, n = 48), pulmonary arteriolar resistance (n = 39), total lung capacity (n = 40), and aortic pressures (n = 50) were also recorded. rPA and pulmonary arterial diameter (dPA) were positively related to mean pulmonary artery pressure (Rs = 0.74, p < 0.0005 for both analyses). For patients younger than 50 years of age, mean pulmonary artery pressure correlated more strongly with rPA than dPA (Rs = 0.77, p < 0.00005, compared with Rs = 0.59, p < 0.005); and vice versa for patients older than 50 years of age (Rs = 0.63, p < 0.005, compared with Rs = 0.75, p < 0.00005). Using a mean pulmonary artery pressure greater than 20 mm Hg as indicative of PAH and a value of rPA > 1, the sensitivity, specificity, and positive and negative predictive values for determining PAH were 70% (26/37), 92% (12/13), 96% (26/27), and 52% (12/23), respectively. On multivariate analysis, rPA was positively related to mean pulmonary artery pressure (p < 0.0005), and negatively related to age (p < 0.0005), but was not related to BSA. By contrast, dPA showed some dependency on BSA (p < 0.0005), as well as on mean pulmonary arterial pressure. In patients younger than 50 years of age, we have found a strong correlation between rPA and mean pulmonary artery pressure in a heterogeneous study population, and this relationship is independent of BSA and sex. The presence of the sign "rPA > 1" is simple in practical CT reading to determine; if this is identified, there is a very high probability of pulmonary arterial hypertension, and clinicians should be alerted to this possibility.

Adolescent↗