Two-scale analysis of a tight gas sandstone.

Tight gas sandstones are low porosity media, with a very small permeability (i.e., below 1 mD). Their porosity is below 10%, and it is mainly composed of fine noncemented microcracks, which are present between neighboring quartz grains. While empirical models of permeability are available, their predictions, which do not compare well with macroscopic measurements, are not reliable to assess gas well productivity. The purpose of this work is to compare the permeability measured on centimetric plugs to predictions based on pore structure data. Two macroscopic measurements are performed, namely dry gas permeability and mercury intrusion porosimetry (MIP), together with a series of local measurements including focused ion beam and scanning electron microscopy (FIB-SEM), x-ray computed microtomography (CMT), and standard two-dimensional (2D) SEM. Numerical modeling is performed by combining analyses on two scales, namely the microcrack network scale (given by 2D SEM) and the individual 3D microcrack scale (given by either FIB-SEM or CMT). The network permeability is calculated by means of techniques developed for fracture networks. This permeability is proportional to the microcrack transmissivity, which is determined by solving the Stokes equation in the microcracks measured by FIB-SEM or CMT. Good correlation with experimental permeability values is only found when using transmissivity from 3D CMT data.

[COPD in elderly patients]. / Bronchopneumopathies obstructives chroniques du sujet âgé.

INTRODUCTION: Patients with COPD are growing in number and are getting older, with 75% of deaths occurring after the age of 75; the proportion of women is increasing. STATE OF THE ART: There are few data regarding COPD in the elderly. The related medical and social demands are significant and rise as age and respiratory disability increase. Admission rates to hospital are increasing and, despite the development of services as alternatives to hospital admission, the portion of healthcare resources taken up by elderly COPD patients continues to rise. PERSPECTIVES: Costly therapeutic interventions for COPD should only be employed if they improve the patient's health related quality of life, which is hard to evaluate and correlates poorly with lung function parameters. Although depression is common and more often found in this condition than in others, it cannot be attributed purely to the effects of COPD. CONCLUSION: Preventive measures and new strategies towards more efficient care of elderly patients with COPD must be developed to improve quality of life and to reduce health care costs.

[COPD in elderly patients]. / Bronchopneumopathies obstructives chroniques du sujet âgé

INTRODUCTION: Patients with COPD are growing in number and are getting older, with 75% of deaths occurring after the age of 75; the proportion of women is increasing. STATE OF THE ART: There are few data regarding COPD in the elderly. The related medical and social demands are significant and rise as age and respiratory disability increase. Admission rates to hospital are increasing and, despite the development of services as alternatives to hospital admission, the portion of healthcare resources taken up by elderly COPD patients continues to rise. PERSPECTIVES: Costly therapeutic interventions for COPD should only be employed if they improve the patient's health related quality of life, which is hard to evaluate and correlates poorly with lung function parameters. Although depression is common and more often found in this condition than in others, it cannot be attributed purely to the effects of COPD. CONCLUSION: Preventive measures and new strategies towards more efficient care of elderly patients with COPD must be developed to improve quality of life and to reduce health care costs.

[Lung disease due to Mycobacterium xenopi excluding AIDS. Apropos of 8 cases]. / Atteintes pulmonaires à Mycobacterium xenopi en dehors du SIDA. A propos de 8 cas.

Between 1994 and early 1999, Mycobacterium xenopi was isolated in 11 HIV-negative patients seen at the Respiratory Disease Department of the Dijon University Hospital. Eight of these patients met the criteria of lung infection. Clinical and radiological features simulated pulmonary tuberculosis which delayed diagnosis until the germ was identified. Treatment is considered to be mandatory though it is difficult to manage and often disappointing. In spite of long-term medical care, sometimes associated with surgery, outcome is currently determined by the underlying disease rather than by Mycobacterium xenopi infection.

Organometallic 99mTc-aquaion labels peptide to an unprecedented high specific activity.

UNLABELLED: A new peptide labeling method that uses the organometallic aquaion [99mTc(H2O)3(CO)3]+ has been developed. METHODS: A selection of amino acids was labeled at different concentrations with the organometallic aquaion, and the labeling yield was determined by high-performance liquid chromatography. This investigation has shown histidine to be a very potent ligand, with specific activities of up to 6 TBq/micromol (160 Ci/micromol) ligand. Histidine derivatives have been coupled to neurotensin(8-13) (NT[8-13]) and have been labeled with the aquaion, resulting in high specific activities with (N(alpha)-histidinyl)acetic acid-NT(8-13) similar to those with histidine. RESULTS: Histidine derivatives of NT(8-13) labeled using this approach fully retained their receptor affinity, showing KD values of all investigated NT analogs below 1 nmol/L on colon carcinoma HT29 cells. Biodistrbution experiments in BALB/c mice showed complete clearance of (N(alpha)-histidinyl)acetic acid-NT(8-13) from the blood after 24 h and no unwanted accumulation in any tissue. CONCLUSION: The novel labeling method using the organometallic 99mTc-aquaion combines the advantage of highest specific activities with minimal functionalization of proteins and peptides under retention of biologic affinity.

Standard combination versus alternating chemotherapy in small cell lung cancer: a randomised clinical trial including 394 patients. 'Petites Cellules' Group.

PURPOSE: to compare standard and alternating administration of chemotherapy combinations in small cell lung cancer (SCLC) patients. MATERIAL AND METHODS: in a multicenter clinical trial, 394 previously untreated SCLC patients were randomised to receive, every 4 weeks, eight courses of either a standard regimen with CCNU, cyclophosphamide, adriamycin (CCA) and VP16 or an alternating regimen (CCA regimen alternating with cisplatin-vindesine-VP16). RESULTS: overall response rate was higher in the standard group (78%) than in the alternating group (64%) (P = 0.0001). Complete response rate was also higher in the standard group (32%) than in the alternating group (18%) (P = 0.004). The median survival in the overall SCLC population was 306 days in the standard group and 272 days in the alternating group (P = 0.08). In limited SCLC patients, median survival was higher in the standard group (421 days) than in the alternating group (328 days) (P = 0.01). Grade III/IV haematological toxicity was lower in patients in the alternating group (25 versus 47%) (P < 0.001). CONCLUSION: the standard regimen was better than the alternating regimen for patients with limited forms of SCLC. The alternating regimen, associated with better haematological safety and ensuring a fairly similar survival, may be considered in patients with extensive SCLC. Pleiomorphic resistance mechanisms to chemotherapy make it difficult to define a non-cross-resistant chemotherapy regimen.

Relative survival analysis of 252 patients with COPD receiving long-term oxygen therapy.

OBJECTIVES: A survival analysis was conducted on patients with COPD receiving long-term oxygen therapy (LTOT) to compare two different statistical methods. METHODS: We used a multivariate crude (observed) survival model (Cox) and a multivariate relative survival model (Hakulinen). Only the latter is able to correct the survival by adjusting it to the normal life expectancy of the studied patients. PATIENTS: Two hundred fifty-two hypoxemic COPD patients (207 male) requiring LTOT were included. Mean PaO2 was <50 mm Hg before oxygen therapy. Mean age was >69 years (SE: 9.9). They had severe bronchial obstruction: mean FEV1 was <33% (10.6) of predicted values, with some CO2 retention: mean PaCO2 was 45.6 (7.1) mm Hg. By December 31, 1995, 189 patients had died (75%) and 13 (5%) were unavailable for follow-up. RESULTS: The overall crude survival was poor: 80.9% after 1 year, 67.1% after 2 years, 34.7% after 5 years, and 7.1% after 10 years. In the crude multivariate analysis (Cox), the negative prognostic factors were age and hypercapnia. The overall relative survival (Hakulinen), corrected for life expectancy, was 82.8% after 1 year, 70.8% after 2 years, 41.5% after 5 years, and 10.25% after 10 years. In the final multivariate relative model, age was no longer significant and the only bad prognostic factor was hypercapnia with a relative risk of 1.97 (1.16 to 3.34). CONCLUSION: This work shows the inadequacy of the Cox observed survival model when it comes to appreciating the real prognostic impact of age, because of the confusing factor associated with a normal life expectancy.

[Synthesis of peptide and pseudo-peptide analogs of cholecystokinin]. / Synthèses d'analogues peptidiques et pseudo-peptidiques de la cholécystokinine.

We describe selective CCKA receptor antagonists, based on the 1-oxo-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid core. Selectivity A vs B is discussed on the basis of molecular modelling. Chemical preparation uses electrophilic cyclization of isocyanates derivating from unnatural tryptophan esters. A stereoselective version of the reaction is given. A few peptides incorporating unnatural tryptophans are prepared, with a view of SAR.

[Unexplained pulmonary edema: demonstration of obstruction to pulmonary venous return by transesophageal echocardiography. Apropos of 4 cases]. / Oedèmes pulmonaires inexpliqués: mise en évidence d'une gêne au retour veineux pulmonaire par échocardiographie transoesophagienne. A propos de quatre observations.

The usual causes of pulmonary edema are left ventricular dysfunction, mitral valve disease or left atrial myxoma. Obstruction to pulmonary venous drainage is a rare and unrecognised diagnosis which should be considered when the usual investigations are unproductive. The authors report four cases in which transesophageal echocardiography showed pulmonary edema to be due to compression of one or more pulmonary veins by a mediastinal mass (2 cases), by the false lumen of dissection of the aorta (1 case) and postoperative stenosis of the pulmonary veins (1 case). These cases underline the diagnostic value of this technique which rapidly provides diagnostic information with privileged visualisation of the pulmonary veins and abnormalities of acceleration of blood velocities in the Doppler mode due to obstruction.

Fatal ball-valve airway obstruction by an extensive blood clot during mechanical ventilation.

A ball-valve airway obstruction by a blood clot cast of almost the whole bronchial tree occurred in a small-cell lung cancer patient, who had been on mechanical ventilation for 9 days. Chest radiographs revealed overinflated lungs. Attempts to remove the cast via fibreoptic bronchoscopy were unsuccessful and the patient died. A postmortem extraction of the clot was performed with a rigid tube. This case is rare because of absence of severe haemoptysis and lung volume reduction.

[Evaluation of the ventilatory function in elderly subjects]. / Evaluation de la fonction ventilatoire chez le sujet âgé.

OBJECTIVES: Many elderly subjects are at risk of respiratory failure due to effect of age on ventilatory system and the deleterious effects of toxins and respiratory diseases. As spirometry is the main technique currently used to detect altered ventilatory function we first used this method in very elderly subjects then compared the results with clinical measurements of chest and abdominal ampliation. METHODS: Among 65 subjects over 75 years of age, with no cardiorespiratory or neuropsychologic impairment and who had undergone spirometry and chest and abdominal ampliation measurements in 1991, 24 were re-examined in 1994 using exactly the same techniques. Forced vital capacity and maximum expiratory volume/second were measured at the patient's home with a previously calibrated spirometer. All tests were run according to the recommendations of the European Respiratory Society. Variations in upper chest, lower chest and abdominal circumferences were also recorded. RESULTS: Mean age of the subjects was 84.1 +/- 3.7 years and all spirometric tests were reproductible within a given measurement session. There was no significant difference for forced vital capacity or for maximum expiratory volume/second between the 1991 and the 1994 values with variations of 2.1 +/- 0.4 and 9.4 +/- 3.4% respectively. Four of the 24 initially asymptomatic subjects had signs of obstruction which resolved in 2 with the salbutamol and/or ipratropium bromide. The correlations between spirometric data and chest and abdominal ampliations were significative. CONCLUSIONS: Spirometry can be an effective tool in elderly patients. In addition to frequent discovery of reversible bronchial obstruction (7 to 41% according to the series), it can be used to screen for reduced ventilatory "reserve". Chest ampliations measures also appear to be simple means of determining which subjects could benefit from physical therapy aimed at improving chest and abdominal musculature.

[Comparison of relative survival vs. classical survival. Apropos of primary bronchial cancer]. / Les apports de la survie relative par rapport à la survie classique. A propos du cancer bronchique primitif.

The aim of the study is to compare the usefulness of a recent relative survival model versus more classical methods for univariate and multivariate survival analysis, applied to a population of patients with surgically cured non small cell lung cancer, in determination of prognostic factors and appreciation of the exact role of age on survival. We studied 156 patients surgically treated between 1975 and 1988. Both univariate and multivariate analysis were performed, using the actuarial method and the Cox model for crude survival and the additive Hakulinen model (1985) for relative survival (total risk of death equal to natural risk of death in general population plus disease specific risk of death) which is an age-adjusted survival corrected for normal life expectancy. In addition, the loss in life expectancy was also calculated. Our 156 patients (including six females), whose age ranged from 30 to 78 (mean age 59) were almost all current or former smokers (97%) and 63% had clinical trouble. Squamous cell carcinoma was the most common histology (76%) before adenocarcinomas (20%). Pneumonectomy and lobectomy were equally performed. Post surgical TNM staging was stage I = 78 (50.3%), II = 23 (14.8%), IIIa = 44 (28.4%), IIIb = 10 (6.5%). By 31 December 1990, 116 patients had died, 24 were alive and 16 lost to follow-up. In univariate analysis, overall survival is (crude/relative): 1 year (75.8%/77.5%), 2 years (53.8%/56.0%), 5 years (28.7%/32.5%), 10 years (14.4%/18.9%). Univariate prognostic factors are histopathology, surgical procedure and post operative TNM staging. The overall loss in life expectancy is 71.4% (5.5 years of life expectancy vs 19.21). The loss is higher for the younger patients than for the older ones (73% for the 30-49 year old group--59.2% for the more than 70 year old group). In multivariate analysis, prognostic factors are: Cox model: post-surgical TNM staging, histopathology and age (RR = 2.18 [1.13-4.23] for patients over 65); Hakulinen model: TNM staging. In this model, age is no longer a significant prognostic factor. In conclusion, this study confirmed the poor prognosis of NSCLC, even if a curative surgical procedure has been possible, with a 5-year survival of 48% for stage I tumours but only 6% for stage III tumours. The most significant prognostic factor is the post-surgical TNM staging. The relative survival model of Hakulinen dismissed age as a significant prognostic factor.(ABSTRACT TRUNCATED AT 400 WORDS)