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Biomedical subjects

E Lafontaine

Publications and source records attributed to E Lafontaine.

At least 19 recordsLinked to original sources
PubMed2001

Anatomic landmarks to estimate the length of the diaphragm from chest radiographs: effects of emphysema and lung volume reduction surgery.

STUDY OBJECTIVES: To define anatomic landmarks that can be used to predict insertions of the diaphragm on chest radiographs and to estimate diaphragm length. DESIGN: Prospective clinical trial with a parallel group design. SETTING: Laboratory investigations in normal volunteers recruited by advertisement and in emphysema outpatients being evaluated for elective bilateral lung volume reduction surgery (LVRS). PATIENTS: Twenty-six normal subjects classified into young and older age groups, with a third group of 13 emphysema patients matched for age and sex with the older group. MEASUREMENTS: Identification and between-group comparisons were made of anatomic landmarks on anteroposterior and lateral chest radiographs obtained at total lung capacity. Predicted landmarks were generated from normal subjects. Within-subject and between-group comparisons were made of diaphragm length index (DLI) based on observed anatomic landmarks (DLIobs) and diaphragm length index based on predicted anatomic landmarks (DLIpred) at functional residual capacity. RESULTS: Anatomic landmarks were not different between the three groups or between male and female subjects, and were not different before and after LVRS in emphysema patients. No difference was found between DLIobs and DLIpred in normal subjects and emphysema patients, but both were smaller in emphysema patients than in normal subjects and increased after LVRS in emphysema patients. CONCLUSION: This study validates the use of anatomic landmarks to estimate DLI. Using these landmarks simplifies the determination of diaphragmatic lengths and could be a useful tool for the evaluation of the functional capacity of the diaphragm, and possibly as a prognostic indicator of patients who are candidates for LVRS.

Adult↗
PubMed1999

Influence of abdomen on respiratory mechanics in supine rabbits.

Previous studies showed that abdominal evisceration has no effect on respiratory system compliance. We hypothesized that this could be related to lung distortion in eviscerated animals. Methods were developed for continuous recording of pleural pressure (Ppl) at various sites over the costal (co) and diaphragmatic lung surface (di) in acutely and chronically instrumented rabbits. We compared deltaPpl,co and deltaPpl,di recorded at mid-lung height during inflations in anesthetized, paralyzed supine rabbits before and after evisceration. Cranial and caudal deltaPpl.co were the same under all conditions. In intact animals, deltaPpl.co and deltaPpl,di were equal at all inflation volumes, whilst in eviscerated animals, deltaPpl,di were smaller than deltaPpl,co, the difference increasing with lung inflation. At any given volume, rib cage circumference (Crc) was smaller after evisceration, but the Crc deltaPpl,co relationship remained unchanged. These results are indicative of non-uniform lung expansion after evisceration and are consistent with model predictions based on cylindrical deformation and lung stress-strain relationship. This deformation should mimic the effect of a reduced lung compliance, keeping respiratory system compliance of eviscerated animals nearly normal. Similar deformation should have occurred also in intact rabbits during strong inspiratory efforts and in the erect posture, because lower Ppl,di than Ppl,co values were observed at the same lung height under these conditions.

Abdomen↗
PubMed1994

[Radiological changes of talc pleurodesis in cases of effusion].

This study is based on the observations of 86 pleurodesis done by talc insufflation during thoracoscopy in 82 patients suffering from benign (8%) and malignant (92%) pleural effusions. Serial chest films were obtained on every patient. Chest computed tomography was obtained in ten patients. The most frequent finding seen in the early phase and one month later was the appearance of loculations (94%) in selective areas of the thorax. Occasionally they take the appearance of airfluid levels (22%). These loculations are characteristically located in the axillary (60%), intrafissural (30%) and paramediastinal (34%) areas of the chest. In the late phase with a mean evolution time of 6 months, these loculations evolve in 77% of patients in areas of pleural thickening. CT of the chest demonstrates the presence of characteristic pleural thickening in the form of coarse (5/12) and/or fine linear densities (7/12) corresponding to talc deposits, on the pleural surface. These modifications are shown by light microscopy examination of the pleural done at the autopsy.

Female↗
PubMed1994

Malignant fibrous histiocytoma in a patient with Blackfan-Diamond anemia.

Blackfan-Diamond anemia, a chronic, pure red cell aplasia, is rare. Malignant fibrous histiocytoma is also uncommon; it can arise in pre-existing bone lesions. The authors describe a 23-year-old man with Blackfan-Diamond anemia complicated by hemochromatosis in whom malignant fibrous histiocytoma developed in the distal femur.

Adult↗
PubMed1993

[Surgical treatment of pneumothorax in AIDS patients].

A retrospective review of the charts of 26 patients with the acquired immunodeficiency syndrome (AIDS) treated at the Hotel-Dieu de Montréal was performed. Patients presented a total of 37 pneumothoraces. Eleven cases were recurrent. Bilateral pneumothoraces were documented in three patients, most of them (17) were severe (> 75%). Pneumocystis carinii pneumonia was the most frequently associated pathology. The initial treatment consisted in chest tube drainage. A definitive treatment was indicated in 7 patients with prolonged air leaks (> 10 days) or without lung expansion. Two median sternotomies with bilateral pleurectomies, bullae plication, and talcage were done, and 5 unilateral thoracotomies with pleurectomies and bullae plications were completed. The post-operative survival was variable and related to diseases associated with the syndrome. AIDS related pneumothoraces is a morbid condition which should be treated on an individual basis.

AIDS-Related Opportunistic Infections↗
PubMed1992

[Palliative treatment with an endoluminal prosthesis for obstruction of the esophagus and the cardia].

Between December 1984 and September 1991, a total of 68 palliative esophageal intubations were performed in 57 patients. The mean age was 64 years, there were 40 males and 17 females. The more frequent causes of esophageal obstruction were malignant tumors of the esophagus (49%), lung (23%) and cardia (19%). Total dysphagia (24.5%), dysphagia to liquids (47%) and esophagotracheal aspiration (14%) were present in these patients. In 65% of patients insertion of the prosthesis was the first attempt at palliation, in the remaining patients it followed the failure of another type of palliation. The decision to palliate esophageal obstruction was established preoperatively in 86% of patients, in the remaining 14% it was decided at the time of surgery. The intubation by pulsion (Atkinson) [1] was successful in 57% of patients and by traction (Celestin) [2] in 86% of patients. The associated morbidity was 36% for the Atkinson prosthesis and 13% for the Celestin prosthesis, although the latter required a laparotomy. The in hospital mortality was 12.5%. The mean survival was 85 days. A normal or semi-solid diet was tolerated by over 60% of patients following intubation. Palliation of esophageal obstruction by intubation improves the quality of life but is associated with a high morbidity.

Cardia↗
PubMed1990

Radionuclide esophageal transit study in detection of esophageal motor dysfunction: comparison with motility studies (manometry)

Radionuclide esophageal transit study (RETS) has been developed to assess motor function of the esophagus. The purpose of this study was to compare RETS to esophageal motility studies (EMS) in detection of motility disorders. A total of 109 consecutive patients without previous history of surgery on the esophagus underwent both RETS and EMS within one month of each other. Final diagnosis was divided into three categories: I--primary esophageal motor disorders (n = 39); II--reflux disease (n = 48); and III--non-cardiac chest pain and/or dysphagia (n = 22). Using EMS as the standard, the results of RETS were as follows: sensitivity for detection of motor dysfunction was 97%, 92%, and 77% for Groups I, II, and III, respectively, while specificity was 91% for Group II and 100% for Group III. Global sensitivity was 92% and specificity was 88%. No clinically significant motor disorders were missed by RETS. In conclusion, RETS is a useful noninvasive test for the screening of patients with symptoms thought to be of esophageal origin.

Adult↗
PubMed1989

Value of plasma NH2-terminal fragment of pro-opiomelanocortin in marking human lung cancer in various clinical settings.

Plasma concentration of amino-terminal segment of pro-opiomelanocortin (N-POMC) was measured by radioimmunoassay (RIA) in 144 patients with various forms of lung cancer during pneumonectomy, at different times of the day after being newly diagnosed and serially, throughout their treatment (surgery or chemotherapy) in order to assess its value as a biomarker in this disease. Normal volunteers, coal miners smoking but without known lung diseases, and the patients with diverse pulmonary disorders served as comparison groups. A significant transtumoral gradient of N-POMC was found at surgery in 15 of 57 (26%) patients. Subjects without lung afflictions had significantly lower N-POMC levels than patients with pulmonary diseases (benign or malignant) only when the blood was drawn before breakfast. Furthermore, fasting levels in all subgroups of patients were higher at any time of the day than nonfasting ones. Finally, N-POMC levels did not decrease significantly after successful treatment of lung cancer (by surgery or chemotherapy) but were markedly higher after relapse. These results suggest that N-POMC, despite the fact that it cannot be used to discriminate lung cancer patients from controls, is a biomarker which may predict relapse in patients successfully treated by chemotherapy for their pulmonary neoplasm.

Adult↗
PubMed1987

Replacement of the superior vena cava with polytetrafluoroethylene grafts combined with resection of mediastinal-pulmonary malignant tumors. Report of thirteen cases.

From 1979 to 1986, we replaced the superior vena cava with polytetrafluoroethylene grafts in 13 patients to enable resection of malignant mediastinal or pulmonary tumors. Five prostheses could be interposed between a tumor-free proximal superior vena cava and right atrium while eight required separate innominate anastomoses (Y grafts constructed intraoperatively). There were no deaths. Phlebograms obtained 15 to 30 days after the operation demonstrated patency in 12 of 13 patients. Long-term (average 24 months) patency was evident in eight. Five patients are alive at 1, 3, 40, 49, and 60 months, a cumulative survival rate of 27% at 3 years.

Adult↗
PubMed1986

Nuclear medicine and esophageal surgery.

The principal radionuclide procedures involved in the evaluation of esophageal disorders that are amenable to surgery are illustrated and briefly described. The role of the radionuclide esophagogram (RE) in the diagnosis and management of achalasia, oculopharyngeal muscular dystrophy and its complications, tracheoesophageal fistulae, pharyngeal and esophageal diverticulae, gastric transposition, and fundoplication is discussed. Detection of columnar-lined esophagus by Tc-99m pertechnetate imaging and of esophageal carcinoma by Ga-67 citrate and Tc-99m glucoheptonate studies also is presented.

Barrett Esophagus↗
PubMed1984

Effect of paraesophageal hernia on sphincter function and its implication on surgical therapy.

Fifteen patients with a paraesophageal hernia were studied with 24 hour esophageal pH monitoring and esophageal manometry to clarify the physiologic aspects of the cardia and resolve controversies over the type of surgical repair. The results were compared with those obtained in 34 randomly selected patients with a sliding hernia and 18 normal control subjects. Sixty percent of the patients with a paraesophageal hernia had an incompetent cardia on 24 hour pH studies which was associated with a lower esophageal sphincter of normal pressure, short overall length, and a small segment exposed to abdominal pressure. In comparison, 70 percent of patients with a sliding hernia had an incompetent cardia which was associated with a lower esophageal sphincter of low pressure, normal overall length, and a short segment exposed to abdominal pressure. With either type of hernia, symptoms were not helpful in determining the competency of the cardia. When urgent surgery is necessary, repair should include an antireflux procedure. If facilities and time permit, more specific evaluation of the cardia can be performed, and if competent, the repair should be limited to reduction of the stomach and closure of the defect.

Adult↗
PubMed1981

Relationship of a hiatal hernia to the function of the body of the esophagus and the gastroesophageal junction.

One hundred two patients referred to our Esophageal Function Laboratory without endoscopic evidence of esophagitis were divided into two groups on the basis of the presence of a hiatal hernia on endoscopic examination. Fifty-three patients had a hiatal hernia and 49 did not. Both groups and 30 normal volunteer subjects had esophageal manometry and 24 hour esophageal pH monitoring. The incompetency of the cardia in patients with a hiatal hernia was dependent upon loss of components responsible for the antireflux mechanism, mainly a decrease in distal esophageal sphincter pressure and a decrease in the length of the sphincter exposed to the positive-pressure environment of the abdomen. These deficiencies were not related to the presence of a hiatal hernia and were similar to those of patients with an incompetent cardia without a hiatal hernia. Patients with a hiatal hernia and an incompetent cardia had significantly more esophageal exposure to refluxed acid than without a hiatal hernia. On the basis of the number of reflux episodes that lasted 5 minutes or longer and radioisotope transit studies, this increased acid exposure was due to both a loss of competency of the cardia and poor esophageal clearance secondary to the presence of a hiatal hernia. Reduction of the hernia and anchoring the distal esophagus into the abdomen not only may improve the antireflux mechanism, but corrects the clearance abnormality as well. The presence of a hiatal hernia has a detrimental effect on the clearance function of the body of the esophagus and may aggravate the effects of gastroesophageal reflux due to an incompetent cardia.

Adolescent↗
PubMed1978

The Concorde and cosmic rays.

In 1976, Air France's Concordes operated 2,642 h of flight time during 772 commercial flights to Rio de Janeiro, Caracas, and Washington. The cosmic radiation dose equivalent rate was measured during each of these flights. The average amount recorded was 0.99 mrems/h. A distinction must be made between the high latitudes (Washington route), on which an average dose equivalent rate of 1.49 mrem/h was recorded, and low latitudes (Rio de Janeiro and Caracas routes), on which the average dose equivalent rate was only 0.78 mrems/h. These figures show that 1976 Concorde passengers and crews were exposed to very low quantities of radiation--very much lower than the maximum value recommended for the general public, which is 500 mrems per year.

Aerospace Medicine↗