Contraction of bronchial smooth muscle and release of mediators by mast cells are involved in asthmatic attacks and are calcium dependent. Therefore, we investigated the effects of a calcium antagonist, nifedipine, in asthma. Ten patients with asthma and documented exercise-induced bronchoconstriction exercised on 2 separate days after single-blind sublingual administration of 20 mg of placebo or nifedipine. The exercise-induced decreases in forced vital capacity, peak expiratory flow, and maximal expiratory flow after exhalation of 50 and 75% of the forced vital capacity were not modified on placebo but were prevented by nifedipine. Ten other asymptomatic patients with asthma and documented exercise-induced bronchoconstriction were studied at rest before and 45 min after nifedipine. The forced vital capacity, peak expiratory flow, and maximal expiratory flows were initially reduced and did not increase after nifedipine. Thus, nifedipine does not modify the basal bronchial tone of patients with asthma but does prevent exercise-induced asthma.
The paper deals with the design of stainless steel exhaust manifolds, focusing on the development of high temperature ferritic grades and their forming capabilities related to the new forming processes, like bending and hydroforming. In particular, it is shown along the presentation, how a niobium stabilized 14%Cr grade can be used in replacement of austenitic grades in many situations of complex shaped manifolds thanks to its combined improved formability and its high temperature resistance up to 950°C. Finally, the authors present a “virtual” thermomechanical fatigue design approach, using a dedicated post processor, which would permit to optimize the design of the fabricated exhaust manifolds, and would lower the development cost and time by limiting both the number of prototype and motor bench tests and, finally, would reduce the risk of failure.
OBJECTIVES The purpose of this time-domain study was to compare pulmonary artery (PA) pulse pressure and wave reflection in chronic pulmonary thromboembolism (CPTE) and primary pulmonary hypertension (PPH).BACKGROUND Pulmonary artery pressure waveform analysis provides a simple and accurate estimation of right ventricular afterload in the time-domain. Chronic pulmonary thromboembolism and PPH are both responsible for severe pulmonary hypertension. Chronic pulmonary thromboembolism and PPH predominantly involve proximal and distal arteries, respectively, and may lead to differences in PA pressure waveform.METHODS High-fidelity PA pressure was recorded in 14 patients (7 men/7 women, 46 +/- 14 years) with CPTE (n = 7) and PPH (n = 7). We measured thermodilution cardiac output, mean PA pressure (MPAP), PA pulse pressure (PAPP = systolic - diastolic PAP) and normalized PAPP (nPAPP = PPAP/MPAP). Wave reflection was quantified by measuring Ti, that is, the time between pressure upstroke and the systolic inflection point (Pi), DeltaP, that is, the systolic PAP minus Pi difference, and the augmentation index (DeltaP/PPAP).RESULTS At baseline, CPTE and PPH had similar cardiac index (2.4 +/- 0.4 vs. 2.5 +/- 0.5 l/min/m(2)), mean PRP (59 +/- 9 vs. 59 +/- 10 mm Hg), PPAP (57 +/- 13 vs. 53 +/- 13 mm Hg) and nPPAP (0.97 +/- 0.16 vs. 0.89 +/- 0.13). Chronic pulmonary thromboembolism had shorter Ti (90 +/- 17 vs. 126 +/- 16 ms, p < 0.01) and higher P/PPAP (0.26 +/- 0.01 vs. 0.09 +/- 0.07, p < 0.01).CONCLUSIONS Our study indicated that: 1) CPTE and PPH with severe pulmonary hypertension had similar PA pulse pressure, and 2) wave reflection is elevated in both groups, and CPTE had increased and anticipated wave reflection as compared with PPH, thus suggesting differences in the pulsatile component of right ventricular afterload. (J Am Coll Cardiol 2001;37:1085-92) (C) 2001 by the American College of Cardiology.
Inhalation of on-demand salbutamol (ODS) several times daily is sometimes the only beta2-agonist prescribed in moderate persistent asthma, whereas a long-acting beta2-agonist should be added. This trial aimed to compare the efficacy of formoterol dry-powder capsule 12 microg b.i.d. (Foradil) and ODS in patients with moderate persistent asthma treated with inhaled corticosteroids, in the conditions of real practice. Two hundred and fifty-nine patients were randomized (formoterol; 130; ODS: 129) in this open, parallel-group trial. The mean increases in morning peak expiratory flow (PEF primary variable) and evening PEF over the 3-month treatment period were statistically significantly higher with formoterol: +25.7 and +24.1 l min(-1), respectively vs. +4.5 and +0.5 l min(-1) respectively with ODS. The increase in FEV1 was statistically significantly higher with formoterol at months 1 and 3. Formoterol reduced the use of salbutamol as rescue medication by two-thirds. The percentages of symptom-free days and nights statistically significantly increased with formoterol (+20% and +33% respectively), but did not significantly change with ODS. Clinically relevant and statistically significant improvement in the mean total score of the St George's Hospital Respiratory Questionnaire was observed in the formoterol group. Adverse events were similar in the two groups. The results show that treatment with formoterol has significant advantages over ODS in patients with moderate persistent asthma.
Diminished exercise capacity in advanced pulmonary histiocytosis X does not appear to be related to ventilatory limitation but may be related to pulmonary vascular dysfunction. Pulmonary hemodynamics and respiratory function were studied in 21 consecutive patients with advanced pulmonary histiocytosis X, and compared with parameters of patients with other severe chronic lung diseases (29 patients with chronic obstructive pulmonary disease and 14 patients with idiopathic pulmonary fibrosis). All patients with pulmonary histiocytosis X displayed severe pulmonary hypertension: mean pulmonary arterial pressure, 59 +/- 4 mm Hg; cardiac index, 2.6 +/- 0.8 L/min/m(2); and total vascular pulmonary resistance, 25 +/- 3 IU/m(2) (p < 0.05, as compared with patients with other chronic lung diseases). Pa(O(2)) was similar in the three groups, whereas FEV(1) was lower in patients with other chronic lung diseases (p < 0.05). In contrast to other chronic lung diseases, the degree of pulmonary hypertension was not related to variables of pulmonary function in pulmonary histiocytosis X. Histopathology was available for 12 patients with pulmonary histiocytosis X and revealed proliferative vasculopathy involving muscular arteries and veins, with prominent venular involvement. Two consecutive lung samples (taken before and after the occurrence of pulmonary hypertension) were available for six patients with pulmonary histiocytosis X, and showed that pulmonary vasculopathy worsened, whereas parenchymal and bronchiolar lesions remained relatively unchanged. These results indicate that pulmonary hypertension in pulmonary histiocytosis X might be related to an intrinsic pulmonary vascular disease, in which the pulmonary circulation is involved independent of small airway and lung parenchyma injury.
Churg-Strauss syndrome is an eosinophil-associated, small vessel granulomatous vasculitis, characterized by late onset asthma, upper airways disease, eosinophilia, and clinical manifestations of systemic vasculitis. Several cases of Churg-Strauss syndrome have been recognized in patients treated with cysteinyl leukotriene-receptor antagonists and weaned off systemic corticosteroids. These cases have led to a general warning on the possible development of Churg-Strauss syndrome after taking cysteinyl leukotriene-receptor antagonists. The authors report five cases of Churg-Strauss syndrome in severe steroid dependent asthmatics in whom inhaled corticosteroids allowed systemic corticosteroid withdrawal. It is concluded that physicians should monitor patients carefully when severe asthma is controlled with any substance allowing withdrawal from (or even avoidance) of systemic corticosteroids. Case-control studies should identify more precisely the risk factors of Churg-Strauss syndrome.
Using an inductive definition of normal terms of the theory of Cartesian Closed Categories with a given graph of distinguished morphisms, we give a reduction free proof of the decidability of this theory. This inductive definition enables us to show via functional completeness that extensions of such a theory by new constants ("indeterminates") are conservative. AMS Subject Classification. 03F05, 03B25, 18D15.
Primary pulmonary hypertension (PPH) is characterized by intimal fibrosis and cell proliferation (including fibroblasts, smooth muscle and endothelial cells) in the distal pulmonary arterial tree. Considerable interest has been generated by recent reports of PPH in human immunodeficiency virus (HIV)-1-infected individuals. Although the lack of evidence for a pulmonary artery infection has suggested that in such cases HIV may act through mediator release rather than by direct endothelial infection, the mechanisms underlying HIV-associated PPH remain poorly defined. Platelet-derived growth factor (PDGF) has the ability to induce smooth muscle cell and fibroblast proliferation and migration. Given these considerations, we have attempted to document a possible role for PDGF in PPH occurring in HIV seropositive and seronegative patients. Using semiquantitative polymerase chain reaction (PCR), PDGF A-chain messenger ribonucleic acid (mRNA) expression was analysed in surgical lung biopsies from 13 HIV seronegative patients and one HIV seropositive patient, all displaying severe PPH. In parallel, lung samples from two patients with HIV-1-associated PPH were studied by immunohistochemistry and in situ hybridization. Results were compared to those obtained in three HIV-1-infected individuals with no pulmonary complication (as demonstrated by clinical, radiological, bacteriological, and necropsy findings) and five control lung biopsies. As compared to controls, PDGF A-chain mRNA expression is elevated in lung biopsies from patients displaying PPH (p=0.029). In HIV-1-associated PPH, interstitial perivascular cells expressing PDGF A-chain mRNA and protein could be detected by in situ hybridization and immunohistochemistry, respectively. Platelet-derived growth factor expression is elevated in lung biopsies of patients displaying primary pulmonary hypertension. Growth factors such as platelet-derived growth factor may play a part in the initiation and/or progression of primary pulmonary hypertension.
BACKGROUND Prognostic evaluation of patients with primary pulmonary hypertension (PPH) requires right heart catheterisation. The development of accurate non-invasive methods for monitoring these patients remains an important task. Cyclic guanosine monophosphate (cGMP) is an indicator of the action of natriuretic peptides and nitric oxide on target cells. Plasma and urinary cGMP concentrations are raised in patients with congestive heart failure in whom they correlate closely with haemodynamic parameters and disease severity. The aim of the present study was to determine whether the urinary concentration of cGMP could be used as a non-invasive marker of haemodynamic impairment in patients with severe PPH. METHODS Urinary cGMP concentrations were measured in 19 consecutive patients with PPH, seven with acute asthma, and 30 normal healthy controls. RESULTS Patients with PPH had higher urinary cGMP concentrations than asthmatic patients or normal healthy controls (p = 0.001). Urinary cGMP concentrations were higher in patients with severe haemodynamic impairment—that is, those with a cardiac index (CI) of ⩽2 l/min/m2 (p = 0.002)—and urinary cGMP concentrations were inversely correlated with CI (r = –0.69, p = 0.002) and venous oxygen saturation (r = –0.65, p = 0.003). CONCLUSION Urinary cGMP concentrations may represent a non-invasive indicator of the haemodynamic status of patients with severe PPH.
The wide spectrum of pulmonary vascular disorders in liver disease and portal hypertension ranges from the hepatopulmonary syndrome characterized by intrapulmonary vascular dilatations, to pulmonary hypertension (portopulmonary hypertension), in which pulmonary vascular resistance is elevated. Since hepatopulmonary syndrome and portopulmonary hypertension have been reported in patients with nonhepatic portal hypertension, the common factor that determines their development must be portal hypertension. The clinical presentations are very different, with gas exchange impairment in the hepatopulmonary syndrome and haemodynamic failure in portopulmonary hypertension. The severity of hepatopulmonary syndrome seems to parallel the severity of liver failure, whereas no simple relationship has been identified between hepatic impairment and the severity of portopulmonary hypertension. Resolution of hepatopulmonary syndrome is common after liver transplantation, which has an uncertain effect in portopulmonary hypertension. The pathophysiology of both syndromes may involve vasoactive mediators and angiogenic factors.
In a pilot study of 29 patients treated for localized small cell lung cancer, three new approaches were introduced, i.e. an increased initial drug dose, an early alternation of chemotherapy and thoracic radiotherapy and initial accelerated and hyperfractionated irradiation. The results were interesting. However, a high rate of fatal toxicity (21%) was observed.
BACKGROUND:The short-term vasodilator response to prostacyclin (PGI2) in patients with primary pulmonary hypertension (PPH) is not only unpredictable but also extremely variable in magnitude. In this retrospective study, we attempted to evaluate in a nonselected population of patients with PPH the degree of vasodilatation achieved during short-term infusion of PGI2 and to investigate whether patients with PPH differed in terms of baseline characteristics and prognoses, according to the level of vasodilatation achieved during initial testing with PGI2. METHODS AND RESULTS:Between 1984 and 1992, 91 consecutive patients with PPH underwent catheterization of the right side of the heart with a short-term vasodilator trial with PGI2 (5 to 10 ng.kg-1.min-1). According to the level of vasodilatation achieved during PGI2 infusion, patients were divided into three groups: nonresponding (NR, n = 40), moderately responding (MR, n = 42), and highly responding (HR, n = 9) patients. All three groups were defined by a decrease in total pulmonary resistance index (TPRi) of < 20%, between 20% and 50%, and > 50%, respectively, relative to control values. Prolonged oral vasodilator therapy was subsequently started only in MR and HR patients. All patients had long-term oral anticoagulant therapy. The survival rate at 2 years (transplant recipients excluded) was significantly higher in HR patients compared with NR and MR patients (62% versus 38% and 47% survivors, respectively; P < .05). Comparisons between groups showed no significant differences in baseline hemodynamics or clinical characteristics except for a longer time between onset of symptoms and diagnosis (ie, first catheterization) of PPH in HR patients than in NR and MR patients (71 +/- 61 versus 35 +/- 34 and 21 +/- 21 months, respectively; P < .05). CONCLUSIONS:In this study, patients with PPH exhibiting a decrease in TPRi > 50% during short-term PGI2 challenge at the time of diagnosis had longer disease evolutions and better prognoses than patients with a lower vasodilator response.
Short-acting beta 2 agonists have a rapid and potent bronchodilating effect and represent the basis of treatment of acute asthma. Whatever the level of severity, the inhaled route is preferred because of its high efficacy/tolerance ratio. The doses and modes of administration depend on the severity of the airway obstruction, the site of management and the available devices. Long-acting beta 2 agonists are administered as regular treatment in moderately-severe to severe chaonic asthma in association to inhaled corticosteroids, mainly by the inhaled route whereas the oral route may be considered for the administration of prodrugs.
PURPOSE: Pulmonary hypertension can occur in patients who have disorders associated with altered platelet serotonin storage, including collagen vascular disease and platelet storage pool disease. We tested the hypothesis that primary pulmonary hypertension (PPH) may be also associated with impaired handling of serotonin by platelets, resulting in increased plasma serotonin levels.PATIENTS AND METHODS: We used radioenzymatic assays to measure serotonin in platelets and plasma and serotonin released during in vitro platelet aggregation in 16 patients with PPH, and in 16 normal controls matched for age and sex. Six patients were restudied after heart-lung transplantation to determine whether serotonin abnormalities persisted after pulmonary arterial pressure returned to normal.RESULTS: Patients had decreased platelet serotonin concentration (1.8 +/- 0.6 x 10(-18) mol/ platelet versus 3.2 +/- 0.2 X 10(-18) mol/platelet in controls; P <0.01) and increased plasma serotonin concentration (30.1 +/- 9.2 x 10(-9) mol/L versus 0.6 +/- 0.1 x 10(-9) mol/L in controls; P <0.001). Serotonin released during in vitro platelet aggregation was higher in patients than in controls. After heart-lung transplantation, platelet serotonin concentrations remained decreased and plasma levels remained increased.CONCLUSIONS: Abnormal handling of serotonin by platelets leading to an increase in plasma serotonin occurs in PPH. The persistent decrease in platelet storage of serotonin after heart-lung transplantation suggests that this platelet abnormality is not secondary to PPH.