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Biomedical subjects

C H Marquette

Publications and source records attributed to C H Marquette.

At least 19 recordsLinked to original sources
PubMed2001

Mucinous bronchioloalveolar carcinomas display a specific pattern of mucin gene expression among primary lung adenocarcinomas.

Lung adenocarcinomas are heterogeneous clinically and histologically. Expression of the mucin genes was analyzed as a molecular marker of glandular cytodifferentiation in primary lung adenocarcinomas. Expression was correlated with histopathologic subtypes of World Health Organization classification with the aim of investigating the histogenesis of primary lung adenocarcinomas. Thirty-four primary lung adenocarcinomas were examined by in situ hybridization for mucin gene expression (MUC1-4, MUC5AC, MUC5B, MUC6-7) and by immunohistochemistry for MUC5AC and MUC5B apomucin expression. Mucinous bronchioloalveolar carcinoma (BAC) had a homogeneous pattern of mucin gene expression different from those of other types of lung adenocarcinoma, involving secreted mucins (MUC5AC, MUC5B, and MUC6) and membrane-bound mucins (MUC1, MUC3, and MUC4). Non-BAC adenocarcinoma and mucinous BAC aberrantly expressed mucin genes MUC3, and MUC3 and MUC6, respectively, which are undetectable in normal fetal and adult lung. Our results show the particular phenotype of mucin gene expression in mucinous type of BACs and the heterogeneous expression of respiratory and nonrespiratory mucins in the other types. This finding supports the theory of a common progenitor cell with the potential of multicellular differentiation. From a practical point of view, the aberrant expression of MUC3 and MUC6 could serve as a diagnostic marker in the management of the mucinous type of bronchioloalveolar carcinomas. HUM PATHOL 32:274-281.

Adenocarcinoma↗
PubMed2001

Mechanical ventilation-induced air-space enlargement during experimental pneumonia in piglets.

Mechanical ventilation-induced air-space enlargement was investigated in a porcine model of multifocal pneumonia. Following the intrabronchial inoculation of Escherichia coli, 9 piglets (22 +/- 2 kg) were ventilated with a tidal volume (VT) of 15 ml/kg for 43 +/- 15 h. Five noninoculated piglets ventilated for 60 h with the same VT served as control animals. Following death, the lungs were fixed and lung morphometry was assessed. In inoculated animals, unventilated infected and normally ventilated noninfected pulmonary lobules coexisted. In normally ventilated lung regions (1) emphysema-like lesions were present, (2) mean alveolar area and mean linear intercept were significantly greater in inoculated than in control animals, and (3) the degree of alveolar distension correlated with the decrease in respiratory compliance. In unventilated lung areas (1) pseudocysts were frequent, (2) alveolar edema was rare, (3) bronchiolectasis was frequent, (4) mean bronchiolar area was greater in inoculated than in control animals, and (5) the degree of bronchiolar distension correlated with the increase in inspiratory plateau pressure. In conclusion, in piglets with severe bronchopneumonia, air-space enlargement rather than pulmonary edema was the major feature of mechanical ventilation-induced lung barotrauma and resembled lesions previously reported in critically ill patients ventilated using high inspiratory pressures.

Analysis of Variance↗
PubMed2001

[Diagnosis and treatment of nosocomial pneumonia: bronchial fibroscopy, protected brushing and/or bronchial lavage is not indispensable].

Nosocomial pneumonia in ventilated patients is a frequent and serious complication of ventilatory assistance. The causal role of these lung infections in the overmortality observed in ventilated patients remains a question of debate, but the therapeutic cost (antibiotics and longer stay in intensive care) is considerable. Unlike the spontaneously ventilating patient, fever and new radiologic opacities in ventilated patients can be caused by many non-infectious conditions often concomitant with bacterial pneumonia. The association of clinical signs (fever, purulent tracheal secretions) and laboratory (leukocytosis, leukopenia, hypoxia) or radiographic (recent persistent alveoloar opacities) findings are suggestive of bacterial pneumonia but do not provide bacteriological proof. In order to avoid unjustified treatments (in patients without bacterial pneumonia) or poorly adapted treatments (broad spectrum empiric antibiotics) that can generate high costs in terms of therapy and epidemiology (emergence of resistance), a certain number of fibroscopic techniques have been proposed to improve the diagnosis of nosocomial pneumonia in ventilated patients. These sophisticated and attractive techniques have however provided rather disappointing results and do not allow sufficiently sure positive diagnosis nor bacteriological proof. Moreover, despite their cost and the difficulty of implementing fibroscopic techniques, no reduction in the mortality of nosocomial pneumonia in ventilated patients has been achieved.

Anti-Bacterial Agents↗
PubMed2000

From normal respiratory mucosa to epidermoid carcinoma: expression of human mucin genes.

Mucous cells in the respiratory tract contribute to the maintenance of the normal epithelial cell population via mechanisms of cell proliferation and differentiation. Mucous cell hyperplasia often occurs as a basic response to injury in the tracheobronchial epithelium. These cells are also thought to be involved in the histogenesis of epidermoid metaplasia. A typical biochemical feature of these cells is mucus secretion. Aberrant glycosylation or under-glycosylation of mucins is well known in cancer; however, the specific role played by mucin genes is at present unclear. To provide information regarding the expression of these genes in squamous metaplasia and squamous cell carcinoma, we analyzed and compared the expression of MUC1-MUC7 genes by in situ hybridization in control respiratory mucosa and lesions associated with neoplasia (hyperplasia, metaplasia and dysplasia) and squamous cell carcinomas. MUC4 was expressed independently of mucus secretion since it was expressed weakly by basal cells and probably by ciliated cells as well as collecting ducts, epidermoid metaplasia with complete squamous cell differentiation, and most of epidermoid carcinomas even well differentiated and keratinized. In squamous metaplasia and dysplasia, MUC4 gene expression was diffuse and less intense than in normal epithelium. MUC5AC was overexpressed in dysplasia as well as in mucous cell and basal cell hyperplasia and undetectable when squamous differentiation was achieved.

Biomarkers, Tumor↗
PubMed2000

Obstructive fibrinous tracheal pseudomembrane. A potentially fatal complication of tracheal intubation.

A series of 10 consecutive cases presenting an obstructive fibrinous tracheal pseudomembrane (OFTP) as a complication of endo-tracheal intubation is presented. The patients developed a thick tubular, rubber-like, whitish pseudomembrane moulding the tracheal wall as a result of short-duration endotracheal intubation. This pseudomembrane firmly adhered to the tracheal wall at the site of the endotracheal cuff. Shortly after extubation, partial detachment of the proximal part of the pseudomembrane produced intermittent positional acute respiratory failure due to valve-manner tracheal obstruction. Immediate mechanical ablation was curative in nine patients, without secondary development of tracheal stenosis. One patient died from acute asphyxiation. The history and the pathological findings of these cases support the hypothesis that this lesion represents an early stage of ischemic tracheal wall injury related to the cuff pressure. Pulmonary physicians should be alerted on this poorly known complication of endotracheal intubation.

Adolescent↗
PubMed1999

Multidisciplinary approach to management of postintubation tracheal stenoses.

The optimal management of postintubation tracheal stenosis is not well defined. A therapeutic algorithm was designed by thoracic surgeons, ear, nose and throat (ENT) surgeons, anaesthetists and pulmonologists. Rigid bronchoscopy with neodymium-yttrium aluminium garnet (Nd-YAG) laser resection or stent implantation (removable stent) was proposed as first-line treatment, depending on the type of stenosis (web-like versus complex stenosis). In patients with web-like stenoses, sleeve resection was proposed when laser treatment (up to three sessions) failed. In patients with complex stenoses, operability was assessed 6 months after stent implantation. If the patient was judged operable, the stent was removed and the patient underwent surgery if the stenosis recurred. This algorithm was validated prospectively in a series of 32 consecutive patients. Three patients died from severe coexistent illness shortly after the first bronchoscopy. Of the 15 patients with web-like stenosis, laser resection was curative in 10 (66%). Among the 17 patients with complex stenoses, three remained symptom-free after stent removal. Bronchoscopy alone was thus curative in more than one-third of the patients. Six patients underwent surgery, two after failure of laser resection and four after failure of temporary stenting. Surgery was always performed with the patient in good operative condition. Palliative stenting was the definitive treatment in nine cases. Tracheostomy was the definitive solution in two cases. This approach, including an initial conservative treatment, depending on the type of the stenosis, appears to be applicable to almost all patients and allows secondary surgery to be performed with the patient in good condition.

Algorithms↗
PubMed1999

Morphological changes induced by extensive endobronchial electrocautery.

Due to recent improvements of safety conditions for therapeutic devices, electrocautery is being considered with renewed interest in the field of therapeutic bronchoscopy. The efficiency of this technique for destructing intraluminal tumours is well documented and makes it an attractive alternative to Yttrium aluminium garnet (YAG) laser photo-coagulation. Little is known, however, about the morphologic changes induced by electrocautery within the bronchial wall structures. This information is, however, important since electrocautery has been proposed as an alternative to other techniques to treat superficial tumours of the bronchial wall. Soft coagulation, with autostop, using two different power setting (40 and 120 W), produced by a new generation of high frequency voltage regulated generators was applied circumferentially to the trachea or left main bronchus, in a series of 52 piglets. Early (48 h) and late effects (6 weeks) were assessed through gross examination (bronchoscopy and autopsy) and light microscopy. Early effects of electrocautery included coagulation necrosis of the mucosa only and intense acute inflammation extending deep into the bronchial structure. The inflammatory phase progressively resolved while extensive transmural fibrosis and deterioration of the cartilage plates developed. The nature and extent of these lesions did not depend upon the energy delivered (40 W versus 120 W). Retractile scar formation and loss of cartilaginous support then produced iatrogenic secondary stenoses. These results do not question the use of electrocautery to palliate endoluminal tumours but should make operators careful when treating extensive infiltration of the bronchial wall.

Animals↗
PubMed1999

Balance between proinflammatory cytokines and their inhibitors in bronchial lavage from patients with status asthmaticus.

Status asthmaticus (SA) is an acute respiratory failure combining an acute bronchospastic reaction with a severe airway inflammation. We previously reported an important influx of neutrophils and an increased secretion of interleukin-8 (IL-8) in patients with SA. The aim of this prospective study was to evaluate in bronchial lavage (BL) of patients with SA (n = 9) under mechanical ventilation (MV) the concentrations of cytokines and related mediators which have the ability to modulate inflammation, either proinflammatory (interleukin-1beta [IL-1beta], IL-6, tumor necrosis factor-alpha [TNF-alpha]), or anti-inflammatory mediators (IL-10, transforming growth factor-beta1 [TGF-beta1]), interleukin-1 receptor antagonist [IL-1Ra], soluble TNF receptor I and II [sTNFRI and II]). To determine the relative importance of both pro- and anti-inflammatory mediators, the net inflammatory activity was analyzed by the capacity of BL fluids (BLF) to increase intercellular adhesion molecule-1 (ICAM-1) expression in the human lung A549 epithelial cell line. These data were compared with those obtained from patients who required MV without respiratory disease (V, n = 4), controlled asthma (A, n = 11), and nonsmoking healthy volunteers (C, n = 8). Levels of IL-1, IL-6, TNF-alpha, and of the active form of TGF-beta1 were significantly higher in SA compared with the other groups. The concentrations of IL-1Ra, IL-10, the latent form of TGF-beta1, and of the sTNFRI and II were not significantly different between SA and V, albeit higher in SA than in A and C. The ratio between IL-1Ra and IL-1beta was significantly higher in patients with SA compared with the other groups, whereas there was no difference for the ratio between both types of sTNFR and TNF-alpha. Despite a marked increase of anti-inflammatory mediators in BL from patients with SA, the net inflammatory activity was found to be proinflammatory and mainly due to the presence of bioactive IL-1beta (79% inhibition of ICAM-1 expression with anti-IL-1beta antibodies) and to a lesser extent TNF-alpha (32% inhibition with anti-TNF-alpha antibodies).

Adult↗
PubMed1999

Characterization of an animal model of ventilator-acquired pneumonia.

To develop an experimental model of ventilator-acquired pneumonia (VAP), we investigated whether healthy piglets could develop endogenously acquired pulmonary infection as a result of prolonged mechanical ventilation (MV). Thirty-three piglets underwent MV with anesthesia, analgesia, and paralysis produced by continuous infusion of midazolam, fentanyl, and pancuronium bromide. Ten animals received antibioprophylaxis with ceftriaxone (ATB group) and 23 received no antibiotics (control group). Eighteen control animals and 9 ceftriaxone-treated animals completed the 4-day study protocol. The presence of pneumonia on day 4 was ascertained by multiple pulmonary biopsy specimens, processed for microscopic examination and quantitative cultures. The anesthetic regimen provided satisfactory electrolyte balance and cardiovascular stability. Under these circumstances, 17 of 18 animals and 4 of 9 animals developed VAP in the control and the ATB groups, respectively. Lesions of different grades of severity were unevenly distributed through both lungs with a predominance and a higher severity in dependent lung segments. Noninfectious lesions frequently associated with VAP in humans were not observed. Pneumonia was usually polymicrobial with a predominance of Gram-negative organisms. Most of the causative organisms originated from the oropharynx. Histologic lesions and lung bacterial concentrations were less in the ATB group than in control animals. We then investigated the effects of intrabronchial challenge with bacterial pathogens in the absence of MV. Intrabronchial bacterial inoculation resulted in the development of pneumonia that spontaneously resolved even when using very highly titrated inocula. Therefore, MV seems to be the main predisposing factor in the development of pneumonia in this model. This model that resembles human VAP in its histologic, bacteriologic, and pathogenic aspects may be useful to further study pathogenesis, diagnosis, prevention, and therapy of VAP.

Animals↗
PubMed1999

Inter-alpha-inhibitor (IalphaI) concentration in pig plasma is independent of acute phase protein response.

Human inter-alpha-inhibitor (IalphaI) has been shown to exert a beneficial therapeutic effect in a porcine model of endotoxin shock. It is therefore useful to have a better understanding of IalphaI metabolism during severe inflammatory syndromes. Experimental bacterial pneumonia was induced in pigs. The acute phase response was highlighted by an increase in pig major acute phase protein (pig-MAP) and haptoglobin concentrations in plasma collected daily over 4 days. In the same samples, the IalphaI levels remained unchanged. Moreover, crossed-immunoelectrophoretic and immunoblot analyses did not show any qualitative modification of IalphaI throughout the experiment. IalphaI has been reported to be a negative acute phase protein in both humans and rats. Here we demonstrated that IalphaI behavior clearly differs in humans and pigs and is definitively species specific.

Acute-Phase Proteins↗
PubMed1999

[Post-intubation tracheal stenosis].

Post intubation tracheal stenosis (STPI) is a rare but serious complication of tracheal intubation and/or tracheotomy. The epidemiology has changed over the last twenty years. The diagnosis is sometimes difficult to establish on clinical grounds alone. Flexible bronchoscopy is often necessary to confirm the diagnosis and to influence treatment. The ideal curative treatment is surgical resection of the stenosis with end-to-end tracheal anastomosis. In patients presenting with definitive or transitory contraindications to this treatment there is a place for interventional endoscopy. Rigid bronchoscopy enables mechanical dilatation of the STPI which can be associated with Nd-Yag laser ortracheal endoprostheses. In certain cases interventional bronchoscopy may be curative. However in all cases the management of such lesions remains multi-disciplinary involving pulmonologists, thoracic surgeons, otolaryngologists and anaesthetists.

Algorithms↗