PubMed Health⌕ Search

Biomedical subjects

S Boussat

Publications and source records attributed to S Boussat.

9 recordsLinked to original sources

Vascular endothelial growth factor synthesis in the acute phase of experimental and clinical lung injury.

Vascular endothelial growth factor (VEGF) is a potent angiogenic and endothelial survival factor, which is abundantly expressed in the normal lung. Conceivably, VEGF may be released by numerous cell types found around the airspaces, including alveolar type 2 cells, alveolar macrophages, and polymorphonuclear neutrophils. Using a bacteria-induced lung injury model in rats, VEGF expression in lung was investigated. Both VEGF protein and VEGF messenger ribonucleic acid (mRNA), 4 and 24 h after bacterial challenge (Pseudomonas aeruginosa), were decreased compared with sham rats. VEGF protein was also investigated in bronchoalveolar lavage (BAL) from patients studied within 7 days of acute respiratory distress syndrome (ARDS) onset and in patients without ARDS. VEGF protein levels in BAL were decreased in patients with ARDS versus those without (14.3 +/- 11.1 pg x mL(-1) versus 76.8 +/- 51.1 pg x mL(-1), p = 0.03). In aggregate, these findings show that the initial phase of acute lung injury is associated with a decrease in vascular endothelial growth factor in the lung. This downregulation may represent a protective mechanism aimed at limiting endothelial permeability, and may participate in the decrease in capillary number that is observed during early acute respiratory distress syndrome.

Animals↗

Predictive factors of death in primary lung cancer patients on admission to the intensive care unit.

OBJECTIVE: To assess the lung cancer patient's prognosis in the intensive care unit with early predictive factors of death. DESIGN: Retrospective study from July 1986 to February 1996. SETTING: Medical intensive care unit at a university hospital. PATIENTS: Fifty-seven patients with primary lung cancer admitted to our medical intensive care unit (MICU). MEASUREMENTS AND RESULTS: Data collection included demographic data (age, sex, underlying diseases, MICU admitting diagnosis) and evaluation of tumor (pathologic subtypes, metastases, lung cancer staging, treatment options). Three indexes were calculated for each patient: Karnofsky performance status, Simplified Acute Physiology Score (SAPS) II, and multisystem organ failure score (ODIN score). Mortality was high in the MICU: 66% of patients died during their MICU stay, and hospital mortality reached 75%. In multivariate analysis, acute pulmonary disease and Karnofsky performance status < 70 were associated with a poor MICU and post-MICU prognosis. For the survivors, long-term survival after MICU discharge depended exclusively on the severity of the lung cancer. CONCLUSIONS: We confirmed the high mortality rate of lung cancer patients admitted to the MICU. Two predictive factors of death in MICU were identified: performance status < 70 and acute pulmonary disease.

APACHE↗

Inflammatory cells as well as epithelial cells in nasal polyps express vascular endothelial growth factor.

In nasal polyps (NPs), locally secreted growth factors are involved in the remodelling of the epithelium and extracellular matrix but little is known concerning vessel remodelling. The in situ expression of vascular endothelial growth factor (VEGF) in NPs and control nasal mucosa (CM) were evaluated and in vitro secretion of VEGF from primary human cultures of nasal epithelial cells (HNECs) was quantified. VEGF expression was evaluated in NP (n=14) and CM (n=6) after immunolabelling. In supernatants from HNECs cultured at air/liquid interface, VEGF was quantified by immunoassay, under baseline conditions and after transforming growth factor-beta1 (TGF-beta1) stimulation. In HNEC lysates, VEGF and VEGF messenger ribonucleic acid (mRNA) were detected using Western blot analysis and reverse transcriptase polymerase chain reaction respectively. VEGF positivity was more frequent in inflammatory cells in NPs (14 of 14) than in CM (three of six) (p<0.05) and in the epithelium in NPs (six of 14) than in CM (two of six) (nonsignificant). Under baseline conditions, the VEGF concentration in HNEC culture medium increased from day 2 to 4, then decreased and became undetectable. VEGF concentrations increased significantly after TGF-beta1 stimulation. In HNEC lysates, VEGF and VEGF mRNA were detected on days 4 and 14 of culture. It was concluded that vascular endothelial growth factor is intensely expressed in situ in nasal polyps, mainly in inflammatory cells but also in epithelial cells. Human nasal epithelial cells are able to secrete in vitro vascular endothelial growth factor. Transforming growth factor-beta1 upregulates this secretion. This suggests that vascular endothelial growth factor, inducing oedema and angiogenesis, could be involved in the pathogenesis of nasal polyps.

Endothelial Growth Factors↗

Expression and regulation of vascular endothelial growth factor in human pulmonary epithelial cells.

Vascular endothelial growth factor (VEGF) is a potent endothelial cell growth and permeability factor highly expressed in rodent alveolar epithelium after injury and repair. To investigate VEGF synthesis in human lung epithelial cells, we examined VEGF expression by cultured cells under basal conditions and after cytokine treatment or oxidative stress. Basal VEGF expression was detected in transformed human epithelial cell lines (A549 and 1HAEo-) and in primary human bronchial epithelial cells with RT-PCR, Western blot, and immunocytochemistry. Among the cytokines tested, only transforming growth factor-beta1 increased the levels of excreted VEGF(165) as measured by ELISA. Under hypoxia (0% O(2) for 24 h), the VEGF(165) level increased fivefold, and this effect was O(2) concentration dependent. VEGF concentrations in the medium of all the cell types studied reached values similar to those found in bronchoalveolar lavage fluids from normal patients. Endothelial cells (human umbilical vein endothelial cells) exposed to conditioned medium from primary bronchial epithelial cell cultures showed an increased growth rate, which was inhibited in the presence of a specific neutralizing antibody to VEGF. These results suggest that lung epithelial cells participate in the endothelial repair and angiogenesis that follow lung injury through the synthesis of VEGF.

Bronchoalveolar Lavage Fluid↗

Relation between respiratory changes in arterial pulse pressure and fluid responsiveness in septic patients with acute circulatory failure.

In mechanically ventilated patients with acute circulatory failure related to sepsis, we investigated whether the respiratory changes in arterial pressure could be related to the effects of volume expansion (VE) on cardiac index (CI). Forty patients instrumented with indwelling systemic and pulmonary artery catheters were studied before and after VE. Maximal and minimal values of pulse pressure (Pp(max) and Pp(min)) and systolic pressure (Ps(max) and Ps(min)) were determined over one respiratory cycle. The respiratory changes in pulse pressure (DeltaPp) were calculated as the difference between Pp(max) and Pp(min) divided by the mean of the two values and were expressed as a percentage. The respiratory changes in systolic pressure (DeltaPs) were calculated using a similar formula. The VE-induced increase in CI was >/= 15% in 16 patients (responders) and < 15% in 24 patients (nonresponders). Before VE, DeltaPp (24 +/- 9 versus 7 +/- 3%, p < 0.001) and DeltaPs (15 +/- 5 versus 6 +/- 3%, p < 0.001) were higher in responders than in nonresponders. Receiver operating characteristic (ROC) curves analysis showed that DeltaPp was a more accurate indicator of fluid responsiveness than DeltaPs. Before VE, a DeltaPp value of 13% allowed discrimination between responders and nonresponders with a sensitivity of 94% and a specificity of 96%. VE-induced changes in CI closely correlated with DeltaPp before volume expansion (r(2) = 0. 85, p < 0.001). VE decreased DeltaPp from 14 +/- 10 to 7 +/- 5% (p < 0.001) and VE-induced changes in DeltaPp correlated with VE-induced changes in CI (r(2) = 0.72, p < 0.001). It was concluded that in mechanically ventilated patients with acute circulatory failure related to sepsis, analysis of DeltaPp is a simple method for predicting and assessing the hemodynamic effects of VE, and that DeltaPp is a more reliable indicator of fluid responsiveness than DeltaPs.

Adolescent↗

Oxygen toxicity and tolerance.

Normobaric oxygen toxicity is well described in all animal species. However susceptibility to oxygen exposure is highly variable according to age, species and strains. Similarly in humans, prolonged high oxygen exposure is reported to induce cough, shortness of breath, decrease vital capacity and increase alveolo-capillary permeability. The toxic FIO2 threshold (length of exposure and level) is still debated. In patients with previous lung injury, this threshold is even more difficult to delineate as pathologic pulmonary lesions might result from hyperoxia or primary lung insult. Oxygen free-radicals play a key role in the pathophysiology of oxygen toxicity. Oxygen resistance or tolerance is obtained with intraperitoneal, intravenous and intratracheal endotoxin or cytokines administration. Previous exposure to high oxygen concentration is also reported to increase survival rate and decrease pulmonary lesions in animal models. Protection may rely on antioxidant enzymes synthesis, nitric oxide production, neutrophils recruitment and modulation of alveolar macrophages activity. In humans, oxygen tolerance might be suspected through several clinical studies reporting favorable outcome after long term-oxygen exposure. Better knowledge of the risks of prolonged high oxygen exposure is important to re-evaluate the goals of mechanical ventilation (FIO2, SaO2, PEEP) and/or to develop treatments to prevent oxygen toxicity (surfactant, antioxidant enzymes).

Animals↗

"I will not bring science to the Bantou country" or how to remedy the medical-cultural conflict in north-south cooperation.

The purely technologic realm of modern medicine is not, at first glance, compatible with the expectations of populations that still considered disease to have a magical dimension. The gap is obvious between physicians and patients coming from different cultures but it can also be detected even when the two parties are from the same background. This medico-cultural conflict is probably one of the main causes of resistance, reticence, omissions, and disappointments that have hindered efforts to better public health. Improvement of individual well-being and sanitary conditions depends not only on available facilities but also on the mentality of those that implement their use. Cultural context should be given serious consideration in strategic decision-making. More extensive use of quality-of-life surveys could be helpful in this regard.

Anthropology, Cultural↗

[Everything is relative...about the Hanoi Institute of Traditional Medicine].

At the Symposium entitled "Health, Culture, and Quality of Life" held in Hanoi in 1993, the authors of this report met the physicians in charge of the Traditional Medicine Institute of Hanoi which works with the World Health Organization for traditional medicine. After an historical overview of the foundation of this center providing research, care, and training under the auspices of the Hanoi School of Medicine, Professor Hoang Bao Chau described a practice based on revision of ancestral traditions in accordance with scientific methods, the resulting synthesis being up-to-date yet in keeping with heritage. This novel and pragmatic approach, which takes into account the complexity of man, offers an opportunity to reflect on the current status of medical practices in the world and on their adaptation to each population at a time when the experience of the Other seems almost impossible to communicate.

Academies and Institutes↗