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Biomedical subjects

P Collard

Publications and source records attributed to P Collard.

At least 19 recordsLinked to original sources
PubMed2006

Gefitinib monotherapy in advanced nonsmall cell lung cancer: a large Western community implementation study.

Epidermal growth factor receptor tyrosine kinase inhibitors represent a new treatment option for patients with advanced nonsmall cell lung cancer (NSCLC). This retrospective study examined to what extent previous clinical trial experience matches large-scale Western community implementation of this treatment. In the Belgian expanded access programme, the data from 513 patients with advanced or metastatic NSCLC, not suitable for further chemotherapy and receiving oral gefitinib 250 mg.day(-1) until disease progression, death or unacceptable toxicity, were analysed. The median (range) duration of gefitinib treatment was 2.3 months (0.0-32.7). Its use was predominantly in second- or third-line treatment. The overall response and disease control rates were 8.9 and 41.2%, respectively. In univariate analysis, response was more common in females and never-smokers. In multivariate analysis, female sex was the only significant predictive factor (odds ratio (OR) (95% confidence interval (CI)) 0.329 (0.129-0.839)). Symptom improvement was reported in 108 patients of whom 32 (29.6%) had an objective response, 66 (61.1%) experienced disease stabilisation and 10 (9.3%) progressed. Gefitinib was well tolerated; only 7.8% of the patients reported grade 3 or 4 toxicity. The overall median survival was 4.7 months, with a 1-yr survival rate of 21%. Survival was strongly influenced by a better performance status (PS) (good PS: hazard ratio (HR) (95%CI) 0.110 (0.077-0.157)) and adenocarcinoma with bronchioloalveolar carcinoma features histology (HR (95%CI) 0.483 (0.279-0.834)). In conclusion, the activity of gefitinib was confirmed in the present large Western community implementation study. Response, present in a small subgroup, led to a rewarding survival and could be predicted by sex only. Baseline performance status and adenocarcinoma with bronchioloalveolar carcinoma features histology were significant factors for survival.

Adult↗
PubMed2000

Osseointegration of composite calcium phosphate bioceramics.

The resistance of macroporous calcium phosphate ceramics to compressive strength generally is low and depends on, among other factors, porosity percentage and pore size. A compromise always is adopted between high porosity, required for a good integration, and mechanical strength, which increases with material density. We improved the strength of macroporous calcium phosphate ceramics of interconnected porosity by filling the pores with a highly soluble, self-setting calcium phosphate cement made of TCP and DCPD. Cylinders of the resulting material were implanted in sheep condyles and subjected to histological analysis after 20, 60, and 120 days. Microradiographs were made of the histological sections. The control material consisted of ceramic that had not been loaded with cement. Progressive ingrowth of bone into the ceramic pores occurred as the cement was degraded during the first implantation period. Marked degradation of the cement was apparent after 2 months, with fragmentation of the cement in most of the pores and the presence of bone tissue between the fragments. All the cement had been replaced by bone after 4 months. Some fragments of cement still were embedded in the newly formed bone. There was no significant difference between the integration of loaded and nonloaded ceramics. Filling the macroporous ceramic pores with a calcium phosphate cement significantly improved the mechanical strength of these ceramics without modifying their integration in the healing bone.

Animals↗
PubMed2000

Accuracy and precision of in vivo bone mineral measurements in sheep using dual-energy X-ray absorptiometry.

We evaluated the precision and accuracy of in vivo measurements of spine bone mineral density (BMD) and bone mineral content (BMC) in five ewes using dual-energy X-ray absorptiometry (DXA, Lunar DPX-L). The short-term in vivo reproducibility expressed as the coefficient of variation (CV) varied from 0.9 to 1.6% for spine BMD and from 1 to 3.1% for spine BMC. The ex vivo measurements, performed in 20 cm of water to simulate soft tissue thickness, correlated closely with the in vivo measurements, yielding an r value of 0.98 and 0.97 for spine BMD and BMC, respectively. The accuracy was determined by comparing the total BMC of each vertebra measured in vivo with the corresponding ash weight. The correlation coefficient between the two measurements was r = 0.98, with an accuracy error of 5.6%. We concluded that the DXA allows a precise and accurate measurement of spine bone mineral in live ewes using the methodology designed for humans.

Absorptiometry, Photon↗
PubMed1999

Rupture of aortic aneurysm with right-sided haemothorax.

A 62-yr-old male with a history of high blood pressure was admitted for persistent dyspnoea and a right-sided pleural effusion, complicated by a recent episode of shock. There was no history of trauma and the patient denied any thoracic pain. A chest tube was inserted which released nonclotting bloody fluid. A thoracic computed tomographic scan of the chest revealed an aneurysm of the inferior third of the descending thoracic aorta. The patient underwent a successful prosthetic graft replacement. We emphasize that rupture of aortic aneurysms should be considered in the evaluation of spontaneous haemothorax even if it is right-sided and not associated with pain.

Aortic Aneurysm, Thoracic↗
PubMed1998

Cytopathological features of solitary fibrous tumor of the pleura: a study of 5 cases.

Solitary fibrous tumor is a rare lesion of serosal membranes. In a pleural location, it may be confused clinically with a localized mesothelioma or a peripheral lung tumor. A transthoracic needle aspiration can be done to obtain material for a diagnosis in these easily accessible tumors. In the literature, there are only sporadic reports of cytology of solitary fibrous tumor in pleural fluid or in material obtained by percutaneous fine-needle aspiration. We had the opportunity to study five such cases by cytology and biopsy and in four cases we could study the resected specimen as well. We want to emphasize the possibilities of approaching diagnosis by cytologic material. A more precise diagnosis can be made if immunohistochemistry can be applied on a cell block or a concomitant biopsy specimen. We shall discuss the differential diagnosis of these tumors on cytologic material and/or biopsy and the usefulness of the CD34 antibody.

Aged↗
PubMed1998

Nocturnal oxymetry in patients with total nasal packing.

Nocturnal oxymetry was recorded in ten otherwise healthy patients undergoing different types of nasal surgery with total nasal packing. Postoperative nocturnal oxymetry was worse than preoperative one in seven patients and judged as abnormal in four. These results indicate that in otherwise healthy subjects, nasal surgery and total nasal packing induce immediate significant changes in nocturnal breathing.

Adult↗
PubMed1997

Solitary fibrous tumor of the pleura: a report of five cases diagnosed by transthoracic cutting needle biopsy.

Five patients had a solitary fibrous tumor of the pleura; a well-known but rare entity. In all cases, biopsy by a transthoracic cutting needle (Tru-Cut; Travenol; Deerfield, IL) yielded specimens adequate for histologic analysis and gave the clue to the diagnosis. In four patients, surgical resection confirmed the diagnosis. The opportunity for and interest in diagnosing these tumors by transthoracic cutting needle biopsy before surgery are discussed. An accurate diagnosis of solitary fibrous tumors of the pleura can be made by a minimally invasive procedure; this allows for a more informed allocation of surgical resources.

Aged↗
PubMed1997

Compliance with nasal CPAP in obstructive sleep apnea patients.

Continuous positive airway pressure (CPAP) is currently the treatment of choice for the majority of patients with obstructive sleep apnea (OSA). After a CPAP trial, the initial acceptance rate is 70-80%. Patients who derive no subjective benefit from such a trial are poor candidates for home treatment with CPAP because they are likely to exhibit lower adherence and compliance rates. About 90% of OSA patients provided with CPAP apparatus will adhere to long-term CPAP treatment. Patients abandoning CPAP do so during the first few months of home therapy, a period during which close monitoring and support is warranted. Because of the strong correlation between the machine run time and effective pressure delivered at the nasal mask (90-95%), the time-counter of the CPAP device is sufficient to monitor compliance in clinical practice, allowing for early intervention in cases of suboptimal use. Longterm acceptors of CPAP display a satisfactory compliance (5-6.5 h of average daily use) which compares favourably with compliance with treatment in other chronic diseases. Lower acceptance and compliance rates have been reported in North America as compared to Europe. This could be related to cultural differences or different routines of prescription and follow-up.

Journal Article↗
PubMed1997

Residual effect of nCPAP applied for part of the night in patients with obstructive sleep apnoea.

The aim of the present study was to assess whether nasal continuous positive airway pressure (nCPAP) treatment, applied for only a few hours at the beginning of the night, has any residual effect on sleep and breathing during the ensuing hours of unassisted sleep in patients with obstructive sleep apnoea syndrome (OSAS). In 27 patients with newly-diagnosed OSAS, effective nCPAP was applied during the first part of the night and then withdrawn. Polysomnographic parameters after nCPAP withdrawal were compared with those of the corresponding part of the diagnostic polysomnography performed a few days or weeks before and with those of the first part of night on nCPAP. After 255+/-63 (mean+/-SD) min of sleep with normalization of sleep and breathing parameters under nCPAP, there was partial improvement of OSAS severity during the remaining 124+/-56 min of nocturnal sleep without treatment; mean oxygen saturation, desaturation index (equivalent to the apnoea/hypopnoea index) and movement arousal index all improved significantly with respect to the diagnostic night (p=0.001). This improvement was not accounted for by a change in sleep architecture. We conclude that there is an improvement in severity of obstructive sleep apnoea syndrome after only 4 h of nasal continuous positive airway pressure. This carryover effect could explain why a number of patients with obstructive sleep apnoea syndrome apply nasal continuous positive airway pressure for only part of the night or not every night.

Adult↗
PubMed1997

Subjective results after uvulo-palato-pharyngoplasty.

The subjective effect of uvulo-palato-pharyngoplasty surgery (U.P.P.P) for snoring was evaluated in 31 patients. Results were obtained following a questionnaire sent to patients after a median follow-up of 10 months, as well as through follow-up visits. Seventy seven point five percent of the patients and their partners were satisfied with the operation. No major complications were noted. Minor complications included pain, transient pharyngonasal reflux and sensitvity problems of the posterior wall of the pharynx.

Adult↗
PubMed1996

Why should we enlarge the pharynx in obstructive sleep apnea?

Patency of the collapsible segment of the pharynx is dependent upon the interplay of anatomic and physiologic factors. The upper airway of the typical patient with obstructive sleep apnea (OSA) is structurally narrowed by fat deposits in the lateral pharyngeal walls. During wakefulness, the upper airway dilator muscles compensate for the structurally reduced pharyngeal size by increasing their activity, thereby pulling the tongue and soft palate forward. As a consequence, the cross-sectional area is relatively preserved, but the shape of the pharynx becomes elliptical along the anteroposterior axis. In the awake patient with OSA, patency of the pharynx is largely dependent upon increased dilator muscle activity. During sleep, the activity of the muscular apparatus of the pharynx decreases causing a critical narrowing. Because anatomic narrowing appears to be a basic feature, enlarging the pharynx should be beneficial, particularly if its lateral diameter can be increased. Whereas facial advancement surgery structurally increases the anteroposterior diameter of the pharynx, thereby accounting for the good results reported with this technique, it is doubtful that uvulopalatopharyngoplasty has a similar effect on either the anter-oposterior or lateral diameters of the pharynx.

Humans↗
PubMed1996

Respiratory failure due to tracheobronchomalacia.

A case is described of tracheobronchomegaly progressing to extensive tracheomalacia, complicated by episodic choking, recurrent pulmonary infections, and irreversible hypercapnic respiratory failure. A Y-shaped tracheobronchial stent was placed endoscopically to splint the trachea open, with excellent clinical and physiological improvement. New stent designs may provide long term palliation in selected cases of diffuse tracheal collapse or stenosis, and offer an alternative to surgical repair.

Airway Obstruction↗
PubMed1996

Movement arousals and sleep-related disordered breathing in adults.

Sleep fragmentation (an increase in the number of short EEG arousals) is considered a major determinant of excessive daytime sleepiness but is seldom quantified in sleep studies, and reference values are scarce at best. We present data on the movement arousal index (MAI) in five groups of subjects: normals, simple snorers, patients with the sleep apnea-hypopnea syndrome (SAHS), and patients with sleep-related oxygen desaturations due to chronic obstructive pulmonary disease or neuromusculoskeletal disorders. In normal subjects, the MAI was 13 +/- 7 (mean +/- SD). MAI was distinctly increased in most patients with SAHS and was strongly correlated with the apnea-hypopnea index and loss of both slow wave and REM sleep. It was corrected to normal by nasal continuous positive airway pressure (CPAP). There was some overlap of MAI between SAHS patients and snorers, suggesting that a minority of nonapneic snorers may suffer from daytime sleepiness due to upper airway dysfunction. Sleep fragmentation is not a feature of sleep-related hypoventilation due to COPD or neuromusculoskeletal disorders, and an increase of the number of movement arousals (MA) is very suggestive of upper airway dysfunction and of potential success of CPAP. Quantification of sleep fragmentation is feasible and clinically useful; it should be included in the assessment of sleep-related breathing disorders.

Adult↗
PubMed1996

Acceptance and long-term compliance with nCPAP in patients with obstructive sleep apnoea syndrome.

Previous studies have generally shown poor effective long-term compliance with nasal continuous positive airway pressure (nCPAP) in patients with obstructive sleep apnoea syndrome (OSAS). We performed a retrospective study of patients treated with nCPAP for more than one year. Compliance was defined as the average number of hours of nCPAP use per day, where hours of use were obtained from the built-in time counter of the nCPAP device, after deduction of the 10% difference between effective use and time counters previously shown by others. We present data on the first 95 patients for whom results were available. The follow-up period was 784 +/- 366 (mean +/- SD) days for the whole group. Compliance was 5 +/- 1.8 h. For a subgroup of 36 patients, we had data on two consecutive follow-up periods (673 +/- 235 and 390 +/- 147 days for the first and second period, respectively). Compliance remained stable (5.2 +/- 1.5 and 5 +/- 2.3 h, respectively). For the whole group, a significant correlation was found between compliance and sleep fragmentation expressed as the movement arousal index (r = 0.226). During a similar 3 year period, 155 patients with a confirmed diagnosis of OSAS were offered a nCPAP trial. CPAP was actually delivered for home use to 117 patients (76%). During this same 3 year period, only 21 patients out of a total of 192 followed-up in our institution quit treatment, mainly due to intolerance or cure. These results indicate that in a nonselected group of obstructive sleep apnoea syndrome patients a high and stable compliance with nasal continuous positive pressure can be achieved, contradicting recent results of other series.

Adult↗
PubMed1996

The single-breath diffusing capacity for carbon monoxide in obstructive sleep apnea and obesity.

BACKGROUND: We have observed high values of single-breath diffusing capacity for carbon monoxide (Dco) in patients with obstructive sleep apnea (OSA). STUDY OBJECTIVES: To confirm this observation and to determine the factors influencing diffusion indices in patients with OSA. As weight excess was found to be the major determinant of increased diffusion indices, the adequacy of various prediction equations was evaluate in obese subjects. DESIGN: Retrospective data collection. SETTING: University hospital. METHODS: DCO was measured in patients with OSA and in nonapneic subjects who served as control SUBJECTS: The results were expressed with respect to our own reference values and also to other prediction equations. RESULTS: In moderate/severe OSA (apnea/hypopnea index [AHI] > or = 30), both DCO and transfer coefficient (KCO) were increased and KCO was positively correlated with AHI and body mass index (BMI). Diffusion indices were not different between patients with moderate/severe OSA and nonapneic control subjects matched for age and BMI. In the latter group, KCO was also correlated with BMI. In our obese patients (BMI, 36.7 +/- 5.6 kg/m2), DCO was about 10% and KCO was 20 to 25% greater than predicted by standard reference equations. CONCLUSIONS: DCO and KCO are increased in a typical population of patients with moderate/severe OSA. This appears to be due to weight excess and not to OSA itself. In obese subjects, whether apneic or not, BMI is a determinant of diffusion indices that are higher than predicted by equations relying on age and stature alone.

Adult↗