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Biomedical subjects

J Remy

Publications and source records attributed to J Remy.

At least 19 recordsLinked to original sources
PubMed1992

Pulmonary arteriovenous malformations: evaluation with CT of the chest before and after treatment.

A total of 109 single or multiple pulmonary arteriovenous malformations (PAVMs) were evaluated with computed tomography (CT) of the chest in 40 patients separated into three groups to study the usefulness of CT (a) in the diagnosis and pretherapeutic management of PAVMs by comparison with selective pulmonary angiography of each lung (group 1: 20 patients), (b) in the follow-up of patients who received treatment (group 2: 27 patients), and (c) as an isolated diagnostic procedure in elderly patients (n = 3) or family members with Osler-Weber-Rendu disease (n = 8) (group 3: 11 patients). Follow-up ranged from several weeks to 10 years (mean follow-up, 4 years). In group 1, conventional and dynamic CT enabled identification of 107 PAVMs (98.2%) (vs 65 PAVMs [59.6%] identified with angiography), with confident segmental location in 56 of 65 PAVMs (86%) and reliable analysis of angioarchitecture in 17 PAVMs (26%) (vs 39 PAVMs [60%] analyzed with angiography). In group 2, progressive aneurysmal retraction was associated with successful occlusion. In group 3, CT enabled noninvasive evaluation of patients unable to undergo treatment and detection of PAVMS in family members.

Adult↗
PubMed1992

Chronic hypersensitivity pneumonitis: high-resolution CT and radiographic features in 16 patients.

To evaluate the manifestations of chronic hypersensitivity pneumonitis at radiography and high-resolution computed tomography (HRCT), findings in 16 patients with this disease were reviewed. To ensure objectivity, 50 patients with other chronic infiltrative lung diseases (fibrosing alveolitis [n = 29], sarcoidosis [n = 16], and miscellaneous conditions [n = 5]) were included. All patients had chronic disease with evidence of fibrosis at HRCT, as indicated by irregular linear areas and architectural distortion. Radiographs and HRCT scans were reviewed separately, in random order, and without knowledge of diagnosis. On radiographs and HRCT scans, the fibrosis in cases of hypersensitivity pneumonitis was situated predominantly in the middle lung zones or showed no zonal predominance. Lung apices and bases were relatively spared in all cases. The distribution of fibrosis in the transverse plane was random in seven cases, subpleural in six, and peri-bronchovascular in three. The distribution of fibrosis can allow distinction of chronic hypersensitivity pneumonitis from other causes of fibrosis in many cases.

Adolescent↗
PubMed1992

Central pulmonary thromboembolism: diagnosis with spiral volumetric CT with the single-breath-hold technique--comparison with pulmonary angiography.

Forty-two patients were prospectively evaluated with spiral volumetric computed tomography (CT) and selective pulmonary angiography of each lung to detect central pulmonary thromboembolism. Spiral volumetric CT images obtained with either 90 mL of 30% contrast material or 120 mL of 12% contrast material were graded as excellent or good in 98% of the examinations (41 patients). Diagnosis of pulmonary embolism with spiral volumetric CT was based on the direct visualization of intraluminal clots: partial filling defects (n = 41; 37%), complete filling defects (n = 51; 46%), "railway track" signs (n = 6; 5%), and mural defects (n = 14; 12%). All 23 patients with normal findings of spiral volumetric CT had normal findings of pulmonary angiography. With spiral volumetric CT, the finding of 112 central emboli (eight main, 28 lobar, and 76 segmental) corresponded exactly to the angiographic findings, but nine intersegmental lymph nodes were erroneously interpreted as filling defects. In one case of normal pulmonary angiographic findings, asymmetry in pulmonary arterial perfusion was misinterpreted as pulmonary embolism with spiral volumetric CT. Spiral volumetric CT can reliably depict thromboemboli in second- to fourth-division pulmonary vessels.

Adult↗
PubMed1992

Computed tomographic evaluation of silicosis and coal workers' pneumoconiosis.

The introduction of computed tomography (CT) has modified the radiologic approach to silicosis and coal worker's pneumoconiosis considerably, allowing earlier recognition and more precise characterization of pulmonary abnormalities than chest radiography. An optimal approach to CT recognition requires an understanding of the main physiologic and pathologic features that are known to occur in both pneumoconioses. This report focuses on the most common CT features of simple and complicated forms of silicosis and coal worker's pneumoconiosis as well as on the optimal scanning protocol. The respective roles of chest radiographs and CT scans in the recognition of pneumoconiosis and follow-up of exposed workers are discussed.

Coal Mining↗
PubMed1991

Transcatheter occlusion of pulmonary arterial circulation and collateral supply: failures, incidents, and complications.

Failures and complications were analyzed retrospectively in 45 patients treated with embolotherapy or occlusion of pulmonary arterial circulation. Pulmonary arterial branches were occluded with steel coils in 19 patients with pulmonary arteriovenous malformations, 17 with hemoptysis of pulmonary artery (PA) origin, and one with massive parenchymal shunt. Bronchial arterial supply to the lung was embolized with small particles in eight cases of hemoptysis and systemic to pulmonary arterial antegrade shunt secondary to chronic thromboembolism. Asymptomatic incidents included catheterization failures, vascular damage, partial occlusion, partial recanalization of the thrombus, ectopic deposition of a coil, and delayed bacterial contamination of the thrombus. A few cases of transient clinical and radiologic signs of pulmonary infarction were observed after complete occlusion of the PA and bronchial artery embolization. This complication was never observed after complete occlusion of main right or left PA, inferior right or left PA, or segmental branches. The management and prevention of these complications, the role of bronchial arterial collateral pathways, and the importance of the site of PA occlusion in the development of pulmonary infarction are discussed.

Arteriovenous Malformations↗
PubMed1991

Assessment of diffuse infiltrative lung disease: comparison of conventional CT and high-resolution CT.

The diagnostic accuracies of conventional computed tomography (CT) and high-resolution CT (HRCT) in examination of the entire lungs were compared prospectively, and the diagnostic utility of a limited number of HRCT sections in the evaluation of diffuse infiltrative lung disease (DILD) was determined in 150 consecutive patients. Conventional 10-mm CT sections were equivalent to 1.2-mm HRCT sections in the recognition of nodules, masses, nodular irregularities of the interfaces, large cystic air spaces, and architectural distortion. Conventional CT was superior to HRCT in the diagnosis of micronodules and infiltrates. However, 15% of micronodules were recognized only on HRCT images because of their small size and low density. Fine bronchial and parenchymal lesions were best seen on HRCT scans. HRCT was the only technique that allowed assessment of the presence of areas of ground-glass attenuation. HRCT improves visualization of small parenchymal structures and allows a confident evaluation of DILD, providing that the entire lungs are studied. Nevertheless, an optimal CT evaluation of micronodular patterns requires additional thick-section CT scans.

Algorithms↗
PubMed1991

Long-term overproduction of collagen in radiation-induced fibrosis.

Collagen metabolism was investigated in the fibrotic tissue which developed in pig thigh muscle 6 to 15 months after acute gamma irradiation. During this period, total collagen deposits in the fibrotic tissue increased 10-fold compared to the healthy muscle tissue. These deposits were composed mainly of type I and III collagen, and the type I/type III ratio was lower in the fibrotic than in the muscle tissue. Small pieces of both fibrotic and muscle tissue were incubated with [14C]proline. The [14C]hydroxyproline content of the fibrotic tissue reflected large concomitant increases in the synthesis of total collagen, mainly of types I and III, which rose 14- and 17-fold, respectively. Similarly, the level of type I and type III procollagen mRNAs rose 9- and 5-fold, respectively, in the fibrotic tissue versus the muscle tissue. These results suggest that procollagen gene transcription or RNA maturation in the cell nuclei is activated in the fibrotic tissue. The possibility that such activation is due to the long-term inflammatory state of this tissue is discussed.

Animals↗
PubMed1990

Fibronectin and collagen gene expression during in vitro ageing of pig skin fibroblasts.

The fibronectin, collagen type I, and collagen type III genes code for three major proteins of the cell matrix. The age-related alterations in their expression were measured during the in vitro lifespan of pig skin fibroblasts. We observed changes in the transcription rate of these specific genes during ageing. The levels of fibronectin and type III collagen mRNA rose markedly during the senescence phase. The level of collagen type I mRNA decreased during cell ageing, while that of beta-actin did not change. As regards proteins, we observed a sharp increase in the secreted noncollagenous proteins and in the total proteins of the cell layer during senescence. On the contrary, the secretion of the collagenous proteins decreased during senescence. Moreover, most of the newly synthesized molecules of collagen were immediately degraded in the cells, before their extracellular secretion. The terminal phenotype of pig senescent cells was therefore characterized by overexpression of fibronectin and type III collagen genes and reduced expression of the type I collagen gene. Surprisingly, for fibronectin and type III collagen, that terminal phenotype resembled the one normally found in the fibroblasts during the processes of tissue repair, cicatrization, and development.

Aging↗
PubMed1990

Congenital cystic adenomatoid malformation of the lung.

Twenty cases of cystic adenomatoid malformation of the lung were observed: 2 had died in utero; the diagnosis was made at birth in 13 infants of which 3 were premature. A Bochdalek's hernia had been diagnosed before birth in 2 cases by echo-tomography. The correct antenatal diagnosis had been made in 2 cases. Two infants had no symptoms, 3 were dyspneic, 8 were in respiratory distress and had to be intubated and ventilated. Two had a prune belly syndrome. Eight infants had a thoracotomy during their first week of life. Pulmonary resections concerning those 13 patients comprised 10 lower lobectomies, 1 of which was associated with a lingulectomy, and 2 upper lobectomies, 1 of which was associated with a middle lobe resection. Five patients were diagnosed and operated upon between 10 months and 8 years of age; 4 had recurrent bronchitis and 1 was diagnosed during the treatment of a gastroenteritis. They had 3 lower and 2 upper lobectomies. Recovery was uneventful in all patients except for 1 who was reoperated upon for intestinal obstruction. Antenatal diagnosis of cystic adenomatoid malformation should become standard. The malformation may be mistaken for a pulmonary sequestration or bronchogenic cyst. Differential diagnosis of a congenital hernia is important.

Child↗
PubMed1990

Subpleural micronodules in diffuse infiltrative lung diseases: evaluation with thin-section CT scans.

Thin-section computed tomography (CT) was performed in 244 patients with infiltrative lung diseases and 29 healthy control subjects to evaluate the frequency, profusion, and diagnostic value of subpleural parenchymal micronodules. These areas of increased attenuation (less than 7 mm in diameter) were analyzed in four groups: coal miners with chest radiographic findings of coal worker's pneumoconiosis (n = 61), coal miners with no radiographic evidence of pneumoconiosis (n = 73), patients with nonoccupational chronic infiltrative lung disease (n = 110), and healthy adults (n = 29). Subpleural parenchymal micronodules were observed with high frequency in pulmonary lymphangitic carcinomatosis, coal worker's pneumoconiosis, and sarcoidosis but were also seen in 14% of control subjects. Predominant sites of lesions were the posterior subpleural areas in the upper lobes. Subpleural parenchymal micronodules have no diagnostic value when observed as an isolated CT finding but may suggest that diagnosis of pneumoconiosis, sarcoidosis, or pulmonary lymphangitic carcinomatosis when observed in association with mild parenchymal lesions.

Adult↗
PubMed1990

Coal worker's pneumoconiosis: CT assessment in exposed workers and correlation with radiographic findings.

To study the signs of coal worker's pneumoconiosis (CWP) at computed tomography (CT), the authors obtained thoracic CT scans in 170 coal-dust-exposed workers who were concomitantly evaluated with conventional posteroanterior and lateral radiography. The profusion and extent of disease was assessed by means of CT in two groups of miners: group 1 (n = 86), miners with worker's compensation and radiographic evidence of CWP, and group 2(n = 84), miners who had applied for compensation without radiographic evidence of CWP. The CT signs of CWP consisted of micronodules, nodules, and progressive massive fibrosis. The comparative analysis demonstrates the superiority of an optimal CT technique over chest radiography in the evaluation of simple silicosis, with improved sensitivity in the detection of small parenchymal opacities. CT provides additional information on the stage of the disease but also clarifies some ambiguities of the ILO classification of small opacities. CT was equivalent to radiography for complicated silicosis, except in the identification of necrosis. CT evaluations are complementary to plain radiography in the assessment of CWP, and the addition of high-resolution CT is useful in achieving a more accurate evaluation of the small parenchymal opacities.

Adolescent↗
PubMed1989

Heparin fragments modulate the collagen phenotype of fibroblasts from radiation-induced subcutaneous fibrosis.

Acute local gamma irradiation of porcine skin induces, as in human skin, an extensive and mutilating sclerosis characterized by continuous expansion of the fibrosis invading the adjacent muscle and by accumulation of the macromolecular components of the extracellular matrix. Collagen synthesis, content, and types were studied in the presence of heparin fragments (100 micrograms/10(6) cells) in the culture medium, by measuring the incorporation of the radiolabeled precursor [3H]proline into confluent primary cultures of porcine fibroblasts obtained from normal and irradiated fibrotic dermis. Enhancement in collagen biosynthesis and deposition and preferential increase in collagen type III synthesis were observed in fibrotic fibroblast cultures when compared to those in normal dermis fibroblasts. The total collagen synthesis and the rate of collagen hydroxylation appear unmodified by heparin fragments both in normal and in fibrotic fibroblast cultures. But heparin fragments induce a 10- and 2-fold decrease, respectively, in collagen type III and type V syntheses by fibrosis fibroblasts. As only minor effects upon collagen type III and V are observed in cultures of normal dermis fibroblasts, these results highly suggest that heparin fragments are capable of specifically modulating the collagen phenotype of fibroblasts derived from radiation-induced dermis fibrosis and thus are able to regulate the fibrotic process.

Animals↗
PubMed1989

Collagen synthesis and deposition in cultured fibroblasts from subcutaneous radiation-induced fibrosis. Modification as a function of cell aging.

Acute local gamma-irradiation of porcine skin induces, as in human skin, extensive mutilating sclerosis, characterized by continuous expansion of the fibrosis invading the adjacent muscle and by accumulation of extracellular matrix macromolecules. Collagen synthesis, content, and types were studied by measuring the incorporation of the radiolabeled precursor [3H]-proline into confluent primary cultures and subcultures of porcine fibroblasts obtained from normal and irradiated fibrotic dermis. A significant increase in collagen biosynthesis and deposition, with a preferential enhancement of type III collagen, was observed in primary cultures of fibrotic fibroblasts when compared to those of normal dermis. However, the percentage (36%) of neosynthesized collagen in relation to the total neosynthesized non-collagenous and collagenous proteins remained unchanged. In subcultures of normal cells, collagen synthesis and content remained constant until about the 10th passage and then progressively declined until death of the fibroblasts, at around the 15th passage. During the senescence phase, normal fibroblasts acquired the capacity to synthesize higher levels of non-collagenous proteins. On the contrary, collagen synthesis and content diminished in subcultures of fibrosis-induced fibroblasts from the second passage, and then progressively declined as a function of aging; particularly the ratio of type III to type I collagen returned to normal values from the second passage. Moreover, these fibroblasts did not become senescent, persisted in synthesizing low levels of collagen, and acquired later (around the 40th passage) a higher capacity to synthesize non-collagenous proteins. These results demonstrate that primary cultures of porcine fibroblasts obtained from normal or radiation-induced fibrotic dermis reproduce the in vivo situation. The results strongly suggest that: 1) the modification of collagen synthesis, content, and types observed in primary cultures of fibroblasts might be due to factors causing long-lasting changes in phenotypic expression and/in stimulation of the expansion of some fibroblast clones engaged in the accelerated synthesis of extracellular matrix macromolecules, such as collagen or non-collagenous proteins. 2) the rapid decrease in this active capacity to synthesize and accumulate collagen, observed in subcultures of fibrosis-induced fibroblasts, might be related to the loss of some activation factors or to the dedifferentiation of the cells. 3) the switch from collagen to non-collagenous protein synthesis during later subcultures of fibroblasts obtained from radiation-induced fibrosis, might be due to molecular modification at the transcriptional or DNA level.

Animals↗
PubMed1989

Abnormal proliferation and aging of cultured fibroblasts from pigs with subcutaneous fibrosis induced by gamma irradiation.

In vivo, fibrotic disorders, which may be due either to injury or disease, are characterized by overproliferation of fibroblasts and overproduction of connective tissue. In vitro, however, most of the fibrotic cell lines studied exhibited no differences in growth potential compared with control cell lines derived from normal skin. In the present study, we investigated the in vitro behavior of fibroblasts derived from pigs with subcutaneous fibrosis induced by gamma irradiation. The cells were isolated from the scar tissue six to 20 months after irradiation. In primary cultures, the cells derived from the fibrotic lesions exhibited greater attachment efficiency and faster proliferation than those of the cells derived from the normal skin of the same animal. In long-term cultures, the differences between normal and fibrotic cells were still greater: the normal skin cells underwent 17 population doublings and then died, whereas the fibrotic cells exhibited a prolonged lifespan, and were still actively proliferating after 80 population doublings. Cell morphology and the number of chromosomes were modified throughout subcultures. These results imply that in the scar tissue active fibrotic cell proliferation continued for years after irradiation and that this activation was expressed in vitro. Therefore, in this pig fibrosis model, the data acquired in the present in vitro studies closely resemble that obtained from earlier in vivo observations.

Animals↗
PubMed1989

Fibronectin and glycosaminoglycan synthesis by fibrotic pig fibroblasts in primary culture.

Synthesis of fibronectin and glycosamingoglycans (GAGs) was studied in fibroblasts from pigs with post-irradiation subcutaneous fibrosis. Fibrosis was developed in the femoral muscle by local gamma irradiation with a dose of 60 Gy. Normal fibroblasts were obtained from the healthy skin of the same animal. To measure GAG and fibronectin synthesis fibrotic and normal fibroblasts were labeled with 3H-glucosamine, 35S-sulfate and 35S-methionine. Fibrotic fibroblasts synthesized 2.5 times as much fibronectin as normal skin fibroblasts but total protein synthesis did not change. Parallel enhanced secretion of hyaluronic acid and dermatan sulfate into the cell culture medium were also observed. GAGs from the pericellular layer of trypsin-digested fibrotic fibroblasts exhibited increased 3H incorporation, but reduced 35S-sulfate incorporation. The largest reduction in the latter was observed for heparan sulfate. These results indicate that the fibroblasts from the well developed fibrotic tissue maintain enhanced synthesis of matrix macromolecules in primary cultures. Structural and/or metabolic changes in secreted GAGs, combined with the stimulation of tissue repair by growth factors may be responsible for the excessive deposition of collagen in post-irradiation fibrosis.

Animals↗
PubMed1988

Control of hemoptysis: systemic angiography and anastomoses of the internal mammary artery.

Twenty-three patients with massive and recurrent hemoptysis were examined with angiography. Particular attention was directed to the internal mammary arteries. Specific causes for the bleeding were tuberculosis (n = 9), aspergilloma (n = 8), bronchiectasis (n = 1), primary systemic amyloidosis (n = 1), congenital and acquired pulmonary venous obstruction (n = 2), chronic pulmonary embolism (n = 1), and bilateral congenital pulmonary artery stenosis (n = 1). Eleven of these 23 patients were treated with systemic arterial embolization, and immediate cessation of bleeding occurred in nine. The recognition of the numerous collateral vessels and anastomoses of the internal mammary arteries is essential for successful percutaneous embolization for hemoptysis. The authors outline these various pathways and collateral vessels.

Adult↗