Unlocking the observation of different proton populations in fluorinated polymers by solid-state 1H and 19F double resonance NMR spectroscopy.

Nafion proton exchange membranes (PEMs) for fuel cell applications are extensively studied and commercially applied, but their unique proton conduction capabilities are still somewhat unexplained. For studying proton dynamics in situ, molecular level spectroscopic techniques have been of limited utility so far. By solid-state 1H and 19F double resonance nuclear magnetic resonance (NMR) spectroscopy using the recently revived multiple contact cross-polarization (MC-CP) pulse sequence along with double-quantum 1H-1H filtering, high resolution proton populations distinct from the dominant water resonance were observed in Nafion for the first time. This methodology quenches signal decay due to spin-lattice relaxation in the rotating frame and enables magnetization transfer between the relatively mobile 1H and 19F spin baths in Nafion. Further studies of these previously unrevealed proton populations will lead to a better understanding of the Nafion proton conduction mechanism and proton exchange processes in general.

Functionalization of Zr-based MOFs with alkyl and perfluoroalkyl groups: the effect on the water sorption behavior.

Stability and sorption of Metal-Organic Frameworks (MOFs) towards water are critical in many applications, and can a priori be modulated through the introduction of suitable organic functional groups on their backbone. We report here the preparation of a series of Zr(iv)-based MOFs functionalized with alkyl and perfluoroalkyl groups and their characterization by X-ray powder diffraction, multi-nuclei ((1)H, (13)C, (19)F) solid state nuclear magnetic resonance analyses, and nitrogen sorption measurements at 77 K. Their water sorption behavior was evaluated at 298 K and related to their physico-chemical features, highlighting both the effect of the confinement and the nature of the functional groups on the hydrophilic/hydrophobic balance.

Optical anisotropy in self-assembled InAs nanostructures grown on GaAs high index substrate.

We present a study of the optical properties of InAs self-assembled nanostructures grown by molecular beam epitaxy on GaAs(11N)A substrates (N = 3-5). Photoluminescence (PL) measurements revealed good optical properties of InAs quantum dots (QDs) grown on GaAs(115)A compared to those grown on GaAs(113)A and (114)A orientations substrate. An additional peak localized at 1.39 eV has been shown on PL spectra of both GaAs(114)A and (113)A samples. This peak persists even at lower power density. Supporting on the polarized photoluminescence characterization, we have attributed this additional peak to the quantum strings (QSTs) emission. A theoretical study based on the resolution of the three dimensional Schrödinger equation, using the finite element method, including strain and piezoelectric-field effect was adopted to distinguish the observed photoluminescence emission peaks. The mechanism of QDs and QSTs formation on such a high index GaAs substrates was explained in terms of piezoelectric driven atoms and the equilibrium surfaces at edges.

Golestan cohort study of oesophageal cancer: feasibility and first results.

To investigate the incidence of oesophageal cancer (EC) in the Golestan province of North-East Iran, we invited 1349 rural and urban inhabitants of Golestan province aged 35-80 to undergo extensive lifestyle interviews and to provide biological samples. The interview was repeated on a subset of 130 participants to assess reliability of questionnaire and medical information. Temperature at which tea was consumed was measured on two occasions by 110 subjects. Samples of rice, wheat and sorghum were tested for fumonisin contamination. An active follow-up was carried out after 6 and 12 months. A total of 1057 subjects (610 women and 447 men) participated in this feasibility study (78.4% participation rate). Cigarette smoking, opium and alcohol use were reported by 163 (13.8%), 93 (8.8%) and 39 (3.7%) subjects, respectively. Tobacco smoking was correlated with urinary cotinine (kappa = 0.74). Most questionnaire data had kappa > 0.7 in repeat measurements; tea temperature measurement was reliable (kappa = 0.71). No fumonisins were detected in the samples analysed. During the follow-up six subjects were lost (0.6%), two subjects developed EC (one dead, one alive); in all, 13 subjects died (with cause of death known for 11, 84.6%). Conducting a cohort study in Golestan is feasible with reliable information obtained for suspected risk factors; participants can be followed up for EC incidence and mortality.

[Moderately abundant hemoptysis revealing endobronchial hamartochondroma]. / Une hémoptysie de moyenne abondance révélant un hamartochondrome endobronchique.

Hemoptysis is rarely the inaugural sign of endobronchial hamartoma. Abundance may range from moderate to massive, and may be life-threatening. We report the case of a 44-year-old woman who was referred to our center with moderate and persistent hemoptysis. A left upper lobe lobectomy was performed. We discuss the therapeutic options in such cases.

Endoscopic esophageal cancer survey in the western part of the Caspian Littoral.

After a hiatus of 30 years an attempt is now being made to re-assess the previously reported very high esophageal cancer incidence rates in the Caspian Littoral. The extraordinarily high incidence rates found in the eastern side of the Littoral, were re-confirmed five years ago for the Turkoman region, using esophageal balloon cytology supplemented by esophagoscopy of suspected cases. The focus this time was on the Ardabil province in the western side of the Caspian Littoral, where the rates reported 30 years ago were moderately high. A pilot chromoendoscopic screening program was scheduled for 650 asymptomatic adults from a randomly selected part of the city of Ardabil and adjoining villages, to evaluate the overall patterns of esophageal disease and to establish the utility of endoscopy as an esophageal cancer screening tool. 504 healthy volunteers, giving a compliance rate of 77.5%, submitted to esophagogastroscopy without any mishaps. Contrary to expectation, no dysplasia or esophageal cancer was found in 914 satisfactory biopsy specimens. Total absence of esophageal cancer or precursor dysplastic changes in the surveyed population in the western part of the Caspian Littoral was at variance with the cancer registry findings of three decades ago for the western part of the Littoral. A plausible explanation could be the improved socio-economic conditions and life style changes which have taken place in the recent past all along the Caspian Littoral, except in the Turkoman Plain.

Distinct pattern of TP53 mutations in squamous cell carcinoma of the esophagus in Iran.

Extremely high rates of squamous cell carcinoma of the esophagus (SCCE) are observed in Iran, reflecting unknown, genetic and/or epidemiological risk factors. Among genetic alterations in SCCE, TP53 mutations are the most frequent, vary among populations, and may provide clues on etiological mechanisms. We have analysed mutations in TP53 (exons 5-8) in 98 SCCE from Iran by temporal temperature gel electrophoresis and direct sequencing. We found 58 mutations in 49 patients (50%), with a high prevalence of C to T transitions at CpG dinucleotides (29.3%). The TP53 mutation pattern in Iran was significantly different from that observed in SCCEs from high incidence areas of China and Western Europe (P=0.007). Moreover, the prevalence of mutations at A : T base pairs (transitions and transversions) was higher in men than in women (38.7% vs 11.1%, P=0.033). COX-2 overexpression was detected in 69% of the cases evaluated (24/35), without significant association with TP53 mutation. Accumulation of nitrotyrosine, a marker of protein damage by excess levels of nitric oxide, was observed in tumor cells in six of 18 [corrected] cases analysed. These results are consistent with the hypothesis that several factors are involved in TP53 mutagenesis in Iran. These factors include a baseline of chronic inflammatory stress, which may have a multiplicative impact on the sensitivity of esophageal cells to exogenous factors of risk.

[Bronchopulmonary disease in drug abusers]. / La pathologie bronchopulmonaire des toxicomanes.

Drug abuse is a growing problem in industrialized countries, opening the way to new diseases of the respiratory tract. It has been demonstrated that regular inhalation of cannabis has the same consequences as tobacco smoking. The same cannot be said for other drugs. Cocaine, amphetamines or crack expose the patient to particular toxic effects: in addition to barotrauma related to the administration route, syndromes of acute respiratory distress have been described. These result either from bronchial reactions, asthma exacerbation or eosinophil bronchopneumonia, or alveolar involvement: intra-alveolar bleeding, pulmonary edema or organized pneumonia. Respiratory complications induced by opiates, often used in injections, are related to central alveolar hypoventilation and/or the development of injury from pulmonary edema or pneumonia. The pathophysiology of these lesions is not perfectly understood. Besides these specific conditions, infection is a major problem in drug abusers, irrespective of the drug: bacterial pneumonia, tuberculosis, HIV infection are much more frequent in this high-risk group. Finally repeated intravenous injections of various drugs designed for oral intake can lead to severe complications such as pulmonary hypertension or toxic interstitial lung disease. Summarizing, respiratory diseases in drug abuses can take on a wide range of quite complex presentations. Occasional or regular use of illicit drugs can lead, not exceptionally, to severe respiratory complications requiring rapid management. Knowledge of the principal complications and the appropriate diagnostic procedures is indispensable.

[Lemierre's syndrome: a case report]. / Le syndrome de Lemierre: a propos d'une observation.

We report a case of Lemierre's syndrome with a pleuropulmonary complication. Lemierre's syndrome is a rare etiology of lung abscess. The diagnosis is clinical and microbiological (anaerobic organisms). This syndrome associates an acute oropharyngeal infection with septic thrombophlebitis of the internal jugular vein (sometimes many days before the lung lesion) and pulmonary abscess formation. Clinicians should be aware of this syndrome that is fatal in 10% of patients, usually after delayed or missed diagnosis. The frequency of Lemierre's syndrome would be higher if antibiotics were given only to pharyngitis patients positive for streptococcus.

Oesophageal cancer among the Turkomans of northeast Iran.

A Caspian Littoral Cancer Registry survey in the early 1970s established northern Iran as one of the highest oesophageal cancer incidence regions of the world. To verify this, an oesophageal cancer survey was carried out between 1995 and 1997 in the Turkoman Plain at the southeastern corner of the Caspian Sea. Oesophageal balloon cytology screening was carried out on 4192 asymptomatic adults above age 30 years in one town and three adjoining villages with a total population of 20 392 people at risk. Oesophagoscopy was performed on 183 patients with abnormal cytological findings. The discovery of two asymptomatic small squamous cell cancers and one 'carcinoma- suspect' implied a prevalence ranging from 47.7 per 100 000 to 71.5 per 100 000. During a 1-year active surveillance, 14 patients were found with clinically advanced oesophageal squamous cell cancer, yielding age-standardized incidence rates of 144.09 per 100 000 for men and 48.82 per 100 000 for women. The very high frequency of oesophageal cancer reported for northern Iran 25 years ago stands confirmed. Differences in incidence rates, then and now, can be attributed to survey methods used and diagnostic criteria applied, but not to socioeconomic factors, which have remained relatively stable. Oesophageal balloon cytology is a practical method of mass screening for oesophageal cancer in Iran.

Esophageal exfoliative cytology samplers. A comparison of three types.

OBJECTIVE: To compare three types of esophageal exfoliative cytology samplers in terms of patient acceptability, ease of use, final destination of the sampler tip in the gastrointestinal tract and cellular yield. STUDY DESIGN: A controlled, single-blind, cross-over study was undertaken to compare the balloon, sponge and sponge-mesh samplers in healthy volunteers. After completing the three procedures in random order, participants were asked about their preferred method. Ease of use was defined as the technician's ability to perform the intubation successfully. Final destination of the samplers was assessed fluoroscopically. Cytopathologists determined the cellular yield of each sampler using the Bethesda System. RESULTS: Sixty-two volunteers participated. The two encapsulated samplers were significantly preferred over the balloon (P < .0001). There was no significant difference in ease of use, final destination or cellular yield of the three techniques. All three samplers were successfully intubated on the first attempt and retrieved adequate numbers of squamous and glandular cells in > 78% of cases. CONCLUSION: All three samplers obtained satisfactory yields of squamous and glandular cells, but the encapsulated samplers were more patient acceptable. The sponge-mesh sampler may be the least complicated sampler for field screening use. Larger-scale studies will be required to test the accuracy of these three samplers for detecting esophageal dysplasia and carcinoma.

[Yellow nail syndrome. Three cases]. / Le syndrome des ongles jaunes. A propos de trois observations.

Yellow nail syndrome is an uncommon diagnosis established on the basis of clinical presentation with slow-growing yellow discolored nails, lymphedema, and pulmonary manifestations. We report 3 new cases with their pulmonary component.

A new approach to the palliation of advanced proximal gastric cancer.

BACKGROUND: The operative mortality and morbidity rates of palliative total gastrectomy can be high, and survival is not extended. The quality of a foreshortened life is often marred by distressing postprandial symptoms and relentless weight loss. These problems can be attributed to the conventional manner of reconstruction after total gastrectomy, with small-bowel gastric reservoirs restricting the amount of caloric intake. Large-bowel gastric reservoirs have greater capacity and empty well if positioned upright within the chest for proper emptying. The scope of a combined palliative total gastrectomy, esophagectomy, and colon pull-through must be kept within the limits of patient tolerance. STUDY DESIGN: A palliative total gastrectomy was performed in 70 patients with incurably advanced cancers of the proximal and middle third of the stomach (TNM stages: II, 4%; III, 26%; and IV, 70%) using the large-bowel as a gastric substitute. The trauma of reconstruction by colon pull-through was lowered by avoiding thoracotomy and by positioning the colon within the lumen of the deepithelialized esophagus. Proximal cervical esophagocolostomy, distal duodenocolostomy, and colocolostomy reestablished gastrointestinal continuity. Follow-up focused on subjective gastrointestinal symptoms and nutritional maintenance. RESULTS: The operative mortality rate was 10%, postoperative complications were not inordinately high, and autopsy findings showed no defects in the technique of reconstruction. The normal esophageal mucosa was readily cored out through the neck and the abdomen, and the remaining esophageal muscular tunnel accommodated the pulled-through segment of colon. Quantitative assessment of postoperative quality of life proved impractical, but none of 58 longterm survivors (mean of 17.1 months for combined TNM stages II, III, and IV) suffered from disabling symptoms or pronounced weight loss. The quality of life, but not its length, appeared distinctly improved. CONCLUSIONS: The frequently encountered problems of abdominal distress and weight loss after palliative total gastrectomy can be averted by safely positioning a colonic gastric substitute within the lumen of the normal esophagus from which the mucosal lining has been extracted.

AIDS-related Pneumocystis carinii pneumonia in the era of adjunctive steroids: implication of BAL neutrophilia.

Factors predictive of mortality in patients with AIDS and Pneumocystis carinii pneumonia (PCP) were identified before the introduction of adjunctive steroids, but they have not been reevaluated since. Because PCP still occurs in AIDS, remaining fatal in some cases, we conducted a multivariate analysis of factors predicting mortality in patients with HIV-positive PCP managed from 1990 to 1995, i.e., after the consensus conference on the use of adjunctive steroids. The predictive value of clinical, laboratory, and bronchoalveolar lavage (BAL) data at admission and during the course of PCP was studied retrospectively using multivariate methods, in 144 patients with AIDS. Overall mortality was 21.5%. The univariate analysis identified seven factors predictive of 90-d mortality: Pa(O(2)) on room air < 60 mm Hg, lactate dehydrogenase > 1,000 IU, albuminemia < 30 g/L, BAL neutrophilia > 10%, nosocomial infection, pneumothorax, and a need for mechanical ventilation. Four of these factors were independently associated with 90-d mortality in the multivariate analysis; among them, two were evaluable at admission, namely, Pa(O(2)) < 60 mm Hg on room air and BAL neutrophilia > 10%, and two during hospitalization, namely, the development of pneumothorax and a need for mechanical ventilation. Moreover, BAL neutrophilia was correlated to occurrence of pneumothorax and a need for mechanical ventilation. In the era of adjunctive steroid use, AIDS-related PCP remains fairly common. Two independent factors evaluable at admission, Pa(O(2)) on room air and BAL neutrophilia, are predictive of death.

[Acute respiratory distress in a patient with sickle-cell anemia]. / Détresse respiratoire aiguë chez une patiente drépanocytaire.

The acute chest syndrome is a frequent complications of sickle-cell disease characterized by chest pain, fever, and new infiltrate on chest x-ray image. Pathophysiologic factors appear to be multifactorial and better known. We report the case of a 28-year-old woman with homozygous sickle cell anemia who developed acute chest syndrome probably secondary to fat embolism.

Cardiac cause of hypoxaemia in a kyphoscoliotic patient.

This report presents the case of a 73 yr-old female in whom kyphoscoliosis, osteoporotic vertebra compression fractures and sternal injury resulted in severe respiratory failure and hypoxaemia. Pulmonary function testing showed moderate restrictive pattern and rare mismatches were found on lung ventilation/perfusion scanning. Transoesophageal echocardiography with contrast studies showed abnormal anatomic mediastinal interactions which led to right-to-left interatrial shunt, through patent foremen ovale. First-intention treatment, because of orthopaedic and respiratory surgical restraints, was to close the shunt using transcatheter devices. Follow-up after 6 months demonstrated that these interauricular umbrella devices corrected arterial hypoxaemia. True right-to-left interatrial shunts can be found in kyphoscoliotic patients, as a result of thoracic deformation, and can be safely treated with percutaneous trancatheter closure.

[Role of thoracic radiography in the management of community-acquired pneumonia]. / Place de la radiographie de thorax pour la prise en charge des pneumonies communautaires.

In patients presenting with a lower respiratory tract infection, it is generally recommended to order a chest X-ray in two circumstances: when the clinical signs suggest the diagnosis of pneumonia or in case of rather atypical symptoms suggesting a potential risk of complications. Indeed, the presence of one or more recent opacities, and more specifically, homogeneous alveolar infiltration(s) remains the gold standard criterion for the diagnosis of pneumonia. One must not however let this rule overshadow certain limitations of the chest X-ray reported in the literature: 1. the misdiagnosis of certain cases of pneumonia or bronchopneumonia seen early; 2. the extent of the infiltration gives only a very relative assessment of severity; 3. the characteristics of the infiltration are only relatively specific for etiological diagnosis. In patients with community acquired pneumonia diagnosed on the basis of clinical signs and radiographic findings, systematically performed series of follow-up X-rays have shown that the initial extension of the infiltration and the rate of its resolution contribute quite variably to the diagnosis of complications. The best indication for ordering a follow-up X-ray before 6 weeks remains an unfavorable clinical course.