Optimal Length of Low Reynolds Number Nanopropellers.

Locomotion in fluids at the nanoscale is dominated by viscous drag. One efficient propulsion scheme is to use a weak rotating magnetic field that drives a chiral object. From bacterial flagella to artificial drills, the corkscrew is a universally useful chiral shape for propulsion in viscous environments. Externally powered magnetic micro- and nanomotors have been recently developed that allow for precise fuel-free propulsion in complex media. Here, we combine analytical and numerical theory with experiments on nanostructured screw-propellers to show that the optimal length is surprisingly short-only about one helical turn, which is shorter than most of the structures in use to date. The results have important implications for the design of artificial actuated nano- and micropropellers and can dramatically reduce fabrication times, while ensuring optimal performance.

Attitudes to brain death and organ procurement among university students and critical care physicians in poland.

PURPOSE: The practice of retrieving vital organs from brain-dead heart-beating donors is legally and medically accepted in Poland, but public beliefs and opinions regarding these matters have not been sufficiently explored. The purpose of this study was to evaluate the attitude of university students to the concepts of brain death and organ retrieval, compared with the attitude of critical care physicians. METHODS: The cohorts of 989 students and 139 physicians completed a questionnaire based on a survey instrument developed in an earlier reported study on Ohio residents. Participants assessed 3 scenarios: (1) brain death, (2) coma, and (3) vegetative state. More than 48% of students classified the patient from the brain death scenario as alive, and 51% of them were willing to donate organs of this patient. Ninety percent of students classified the patients in coma and in a vegetative state as alive, but still 34% of them would donate organs of those patients. The group of physicians properly determined the patients' diagnoses, but 10% of them accepted organ procurement from patients in coma and in a vegetative state. CONCLUSION: Our results supported the earlier observations of low public knowledge and inadequate understanding of brain death criteria and organ procurement processes. The majority of students were willing to accept organ procurement from severely ill but alive patients, in contrast with physicians. A considerable increase in public educational activity in this field is urgently recommended.

[The Incidence of occupational asthma in Alsace from 2001 to 2002. Results of intensification of the ONAP project in Alsace (2001-2002). Regional specificities]. / L'asthme professionnel en Alsace: quelques particularités régionales. Résultats de l'intensification locale de l'ONAP en 2001-2002.

INTRODUCTION: A national surveillance programme (ONAP project) was created in France in 1996 by two professional societies to estimate the incidence and identity the characteristics of occupational asthma. MATERIALS AND METHODS: In 2001 and 2002 chest physicians and occupational physicians in Alsace were intensively solicited for better voluntary reporting of cases of occupational asthma. The objective of this study was to evaluate the consequences of such a procedure on the number of cases reported, with a view to collecting comprehensive data. RESULTS: The mean annual incidence of occupational asthma was estimated at 126 cases per million workers with a female predominance (52.4%). Flours and isocyanates represented 40% of the suspected agents. Isocyanate asthma (21% of the total) was reported mainly in workers in the car supply industry, and seems to be a specific feature of the region. Persulfates represented 5.3% of the cases; latex and aldehydes 2.6%. The study also points to emergent aetiologies and work risks, i.e. quaternary ammonium compounds in disinfecting detergent products used by cleaners and healthcare workers. CONCLUSION: This study, which allowed better assessment of the real incidence of OA in Alsace and better detection of substances and occupations at risk, is an incentive to continue our Surveillance programme.

[The diagnosis and management of occupational asthma]. / Diagnostic et prise en charge de l'asthme professionnel.

INTRODUCTION: Occupational asthma (OA), with a latency period induced by multiple exposures, is characterized by immunological sensitization to the responsible agent, based on both an IgE mediated mechanisms and non specific bronchial hyper responsiveness. DIAGNOSTIC METHODS: In the diagnosis of OA, the medical history is obviously the starting-point. Onset of respiratory symptoms at work and resolution on vacation are indications of the diagnosis. After analysis of several publications, this element appears to have the best level of proof (grade 2+) according to the criteria of evidence-based medicine. A visit of the workplace, with the cooperation of the industrial physician, is essential to characterize the nature of the exposure. Positive immunological tests (skin tests and/or specific IgE) associated with objective criteria of symptoms related to work (modification of PEFR, lung function and/or nonspecific bronchial hyper responsiveness) will confirm the aetiological diagnosis of OA. Specific bronchial provocation tests performed in the laboratory allow the identification of new agents involved in OA and are necessary when other investigations are discordant or unavailable. OA needs a stepwise approach including induced sputum eosinophilic counts and measurements of exhaled nitric oxide. MANAGEMENT OF OA: OA requires removal from the workplace because persistence of exposure to respiratory sensitisers may lead to an increase and prolongation of asthma symptoms. However, removal from the workplace can have tremendous professional, financial and social consequences, and sometimes a compromise must be found with reduction of exposure by various methods combined with adequate treatment. The pharmacological treatment of patients with OA should be the same as for patients with non OA, the use of bronchodilators and corticoids depending on the severity of asthma. Concerning the medico-legal aspects, OA can be recognised as an occupational disease. In France OA is included in several tables of work-related diseases.

Reported incidence of occupational asthma in France, 1996-99: the ONAP programme.

AIMS: To estimate the general and specific incidence of occupational asthma in France in 1996-99; and to describe the distribution of cases by age, sex, suspected causal agents, and occupation. METHODS: New cases of occupational asthma were collected by a national surveillance programme, based on voluntary reporting, named Observatoire National des Asthmes Professionnels (ONAP), involving a network of occupational and chest physicians. For each case, the reporting form included information on age, sex, location of workplace, occupation, suspected causal agent, and methods of diagnosis. Estimates of the working population, used to calculate incidence rates by age, sex, region, and occupation, were obtained from the Institut National de la Statistique et des Etudes Economiques (INSEE) and from the French Securite Sociale statistics. RESULTS: In 1996-99, 2178 cases of occupational asthma were reported to the ONAP, giving a mean annual rate of 24/million. Rates in men were higher than rates in women (27/million versus 19/million). The highest rate was observed in the 15-29 years age group (30/million). The most frequently incriminated agents were flour (20.3%), isocyanates (14.1%), latex (7.2%), aldehyde (5.9%), persulphate salts (5.8%), and wood dusts (3.7%). The highest risks of occupational asthma were found in bakers and pastry makers (683/million), car painters (326/million), hairdressers (308/million), and wood workers (218/million). CONCLUSION: Despite likely underreporting, the number of cases of occupational asthma reported to the ONAP was approximately twice the number of compensated cases over the same period. The relevance of the programme is confirmed by the reproducibility of the results year after year, and its consistency with other surveillance programmes. The ONAP programme is useful for the identification of targets for primary prevention.

[Asthma from tropical abachi wood]. / L'asthme au bois d'abachi.

We report the case of a 28-year old man suffering from rhinitis and asthma which appeared 8 years after exposure to different woods, especially abachi wood. Serial PEFR monitoring at work and away from work were consistent with occupational asthma. Spirometry showed an airway obstruction, and metacholine inhalation test was positive. Skin prick-tests performed with different woods were only positive to abachi wood extract. The search for specific IgE was positive to abachi wood (4, 98 KU/l, class 3). The diagnosis of occupational asthma caused by exposure to abachi wood was established, the mechanism underlying this asthma was IgE mediated. Despite respiratory protection measures, the patient had persisting symptoms and was laid off. The German service for social cover asked for an expert evaluation: specific nasal and inhalation provocation tests performed by exposure to fine abachi wood dust were positive. This is an observation with a double significance: first, although the mechanisms underlying wood occupational asthma remain largely unknown, an IgE mechanism for abachi wood was demonstrated; second, legislation is different in France and Germany where occupational asthma will only be acknowledged if inhalation tests are positive.

Prevalence of Shiga toxin-producing Escherichia coli in ground beef and cattle feces from King County, Washington.

Shiga toxin-producing Escherichia coli (STEC) is increasingly recognized as a common cause of diarrhea. STEC infection is a major public health threat because of its ability to cause serious and potentially life-threatening illnesses. The main reservoirs of STEC are believed to be the intestinal tracts of animals. Several studies have investigated the prevalence of STEC in various food items. The objective of this study was to determine the prevalence of STEC in the Seattle ground beef supply. In addition, the relative amount of STEC contamination between stores was compared, and possible differences between types of ground beef based on fat content (9, 16, and 23%) were investigated. A survey of Stx-I and/or Stx-II genes in fecal samples from cattle at a local slaughterhouse was also conducted. Of 296 ground beef samples tested from area retail grocery stores, 16.8% were positive for the presence of the toxin genes. Our data showed that there was no statistically significant difference (P > 0.05) in the prevalence of STEC between the ground beef samples of different fat contents and between grocery store chains. Of the 103 cattle fecal samples tested, 19 (18.4%) were found positive for the presence of Stx-I and/or Stx-II genes. The presence of a rather high percentage of STEC in the food supply in the absence of large number of cases suggests that not all STEC lineages are pathogenic for humans.

Occupational asthma in France: a 1-yr report of the observatoire National de Asthmes Professionnels project.

Observatoire National des Asthmes Professionnels (ONAP) was created in 1996 by two French professional societies to estimate the incidence of occupational asthma and to promote preventive measures against it. Occupational and chest physicians were asked to report newly diagnosed cases of work-related asthma and reactive airway dysfunction syndrome (RADS), the information collected included age, sex, occupation, suspected causal agents and diagnostic methods. In 1997, 82.3% of 559 cases reported (64% males, mean age 36 +/- 13 yrs) involved occupational asthma, 4.7% RADS and 12.7% atypical asthma syndromes. Incidence rates (expressed as number of cases per million workers) showed a regional variation that ranged from 4 to 73 (national mean: 25.7). The most frequently suspected agents were flour (23.3%), followed by isocyanates (16.6%), latex (7.5%), aldehydes (5.5%), and persulphates (4.1%). Occupations at risk were bakers (23.9%), healthcare workers (12%), painters (9.1%), hairdressers (5.2%), wood industry workers (4.8%) and cleaners (3.5%). These results are compared to those of other systems set up in Europe and North America. Because of the considerable bias inherent in a surveillance system based on voluntary, reporting, the number of occupational asthma cases reported is probably lower than the real incidence. Nevertheless, the French National Observatory for Occupational Asthma encourages physician awareness of occupational asthma and provides an estimate of its incidence and aetiologies in France.

Anaphylactic reactions after therapeutic injection of mistletoe (Viscum album L.).

Mistletoe (Viscum album) is a plant that is semiparasitic of several trees: apple, oak, pine trees, etc. Because of the probable cytolytic action of one of the leaf's most abundant composites, in some countries mistletoe is used as a complementary medicine. Although only a few adverse reactions have been noted (cephalea, fever), cases of anaphylactic shock have been described. We present three cases of severe reaction after injection of mistletoe extract. Two of the patients had cancer. The third, whose brother had cancer, used the plant for preventive purposes. We discuss the danger of possible severe reactions due to the use of products employed in so-called alternative therapies.

Quaternary ammonium compounds and occupational asthma.

OBJECTIVE: Quaternary ammonium compounds, among which benzalkonium chloride is one of the best-known, are commonly used as antiseptics, disinfectants, detergents and preservatives. They can cause occupational asthma, which however, has been rarely reported so far, despite wide use of these products. We report three such cases. Possible mechanisms causing asthma are discussed, taking into account their characteristics. METHODS AND RESULTS: Our patients, all female nurses, manifested asthma symptoms upon handling disinfectant solutions containing benzalkonium chloride. Work-related fall in PEFR was observed in all of them. The diagnosis was confirmed by challenge tests where the patients were exposed, in a closed chamber, to suspected disinfectant contained in a tray. All of the women developed early or delayed symptoms upon exposure. Similar challenge tests to placebo or other disinfectants devoid of quaternary ammonium compound were negative. CONCLUSION: These three cases, in addition to others reported in the literature, point out an as yet poorly known etiology of occupational asthma to quaternary ammonium compounds in hospital employees. The exact mechanism of the action remains unexplained.

[Occupational asthma caused by a coloring reagent]. / Asthme et rhinite professionnels à un colorant réactif.

A case of occupational asthma associated with rhinitis and conjunctivitis occurred in a patient working in a textile factory and exposed to different coloring reagents is reported. Symptoms appeared in phases correlated with changes in the use of the coloring reagents. Prick tests were carried out with the different coloring reagents and were positive for the yellow color. The test was followed by a clear increase in bronchial hyperreactivity to methacholine. Some individual preventive measures, such as wearing a face mask, led to reduction then disappearence of the symptoms.

Identification of a novel Ran binding protein 2 related gene (RANBP2L1) and detection of a gene cluster on human chromosome 2q11-q12.

The giant 358-kDa protein Ran binding protein 2 (RanBP2/Nup358) is localized at the cytoplasmic side of the nuclear pore complex and likely constitutes the Ran-GTP binding site at the cytoplasmic face of the complex. RanBP2/Nup358 furthermore acts as a chaperone for red/green opsin molecules. Here, we report on the physical mapping of human RanBP2 between markers D2S340 and D2S1893. A duplication of the 5'-end sequence of RanBP2 occurs within 3 Mb distal to RanBP2. Detailed sequence analysis resulted in primers specific for this distal duplication. Polymerase chain reaction-based screening of cDNA libraries indicates that this transcript, called RanBP2alpha (HGMW-approved symbol RANBP2L1), is expressed in several tissues. Screening of a fetal brain cDNA library yielded a 4057-bp partial cDNA clone for RanBP2alpha. Its 5'-end is almost identical to RanBP2, whereas its 3'-part is distinct from RanBP2. Northern blot analysis using a probe of the 3'-untranslated sequence of RanBP2alpha detected in several tissues an 8-kb transcript representing the full length of the transcript. In pancreas and placenta, an additional transcript of 14 kb was detected. PAC clones containing the bona fide RanBP2 sequences were localized to 2q11-q12 by FISH analysis, and a region of high similarity was detected on 2p11-p12. In summary, we have identified a RanBP2 gene cluster on 2q11-q12 together with a novel gene termed RanBP2alpha, with high sequence similarity to RanBP2.

Construction of a gene map of the nephronophthisis type 1 (NPHP1) region on human chromosome 2q12-q13.

A gene for the autosomal recessive kidney disorder juvenile nephronophthisis (NPH) is located on chromosome 2q between markers D2S1893 and D2S1888. Recently, the presence of large homozygous deletions was described in the majority of NPH patients. We constructed an integrated YAC/PAC contig of 54 markers and 30 PAC clones that encompasses this deletion and the flanking inverted duplication. Thirty-six novel sequence-tagged site markers were generated for this region of 2-3 Mb, 22 of which represent PAC ends. Ten of 18 multiplex NPH families show a homozygous deletion for 8 consecutive markers. BlastN database search and expressed sequence tag (EST) mapping led to the localization of 18 EST clones to the integrated contig, representing 11 putative transcribed sequences. Seven EST clones were localized to the NPHP1 region between D2S1893 and D2S1888. Two EST clones, zc07a11 from a human parathyroid tumor library and yy63e10 from a multiple sclerosis lesion library, are located in the deletion region. PCR amplification experiments indicate that zc07a11 represents a chimeric cDNA. Through FISH analysis the NPHP1 deletion region was localized to 2q12-q13. In summary, our study provides a high-resolution physical map of the NPHP1 region with 7 precisely localized expressed sequences, 2 of which have recently been shown to be part of a gene for NPH. These data will alleviate the identification of further genes of a homozygous gene deletion syndrome in patients with NPH and oculomotor apraxia and will be instrumental in the characterization of the molecular mechanism leading to the large homozygous deletion in this region. The data furthermore provide an important step toward the construction of a sequence-ready PAC contig of this region.

Increase in non-specific bronchial hyperresponsiveness without specific response to isocyanate in isocyanate-induced asthma: a pilot study.

Increased non-specific bronchial hyperresponsiveness (BHR) has been reported after positive reaction to isocyanates in patients with isocyanate-sensitive asthma. The increased responsiveness may, however, also precede the asthma attack. We therefore compared non-specific BHR to a cholinergic agent before and after exposure to toluene-diisocyanate (TDI) that induced no asthma symptoms in 11 workers with isocyanate-related asthma. Patients were exposed for 3 consecutive days to progressively increasing doses of TDI (5, 10, and 20 ppb min-1 for 20 min) in an exposure chamber with continuous TDI monitoring. No immediate nor late asthmatic bronchial reaction was observed in any patient after any dose of TDI during or after challenge. A significant increase in non-specific BHR was noted 24 h after the last dose of TDI challenge, however. This increase was at least one doubling dose for seven of 11 patients. In conclusion, our study shows that, in patients with isocyanate-induced asthma, exposure to TDI induces a slight but significant increase in non-specific BHR in the absence of any immediate or late bronchial response to isocyanate. This result, which requires further confirmation, may justify a proposal to measure non-specific BHR, even after a negative specific inhalation test to TDI, as an additional diagnostic element for TDI-induced occupational asthma, to help lower the percentage of the undetected occupational asthma cases.

Molecular cloning of the interleukin-1 gene cluster: construction of an integrated YAC/PAC contig and a partial transcriptional map in the region of chromosome 2q13.

Genes of the interleukin-1 (IL-1) gene cluster localized on chromosome 2q13 are implicated in many physiological and pathophysiological processes. We present here a high-resolution physical map of this region between markers D2S2008 and D2S4/PAX8. An integrated YAC/PAC contig and a partial transcriptional map were constructed by STS-constent mapping using the CEPH YAC library and three PAC libraries. A total of 3 YACs, 34 PACs, and 56 STSs were integrated: 33 newly generated probes to PAC end sequences, 9 polymorphic and 4 nonpolymorphic markers, 5 known genes, 4 expressed sequence tags, and 1 pseudogene. Within the map, a complete PAC contig of > 1 Mb encompasses the IL-1 gene cluster and PAX8, a paired-box-containing gene. This allowed us to define the transcriptional orientation of GLVR1, IL1B, and IL1RN and to show that PAX8 is localized outside the IL-1 gene cluster. FISH analysis localized PAC clones containing the IL-1 gene cluster to 2q12-q13. The data provide the basis for further characterization of the IL-1 gene cluster and for the construction of a sequence-ready PAC contig of this region.

Lung auscultation in airway challenge testing.

The appearance of wheezes and changes in inspiratory breath (vesicular) sound intensity (BSI) were monitored in patients undergoing routine methacholine challenge test (MCT). The results were compared with changes in spirometry and to airway hyper-responsiveness (AH). Fifty-four patients were examined. Spirometry was performed before and after the inhalation of cumulative doses of methacholine starting from 25 micrograms; a fall in forced expiratory volume in 1 s (FEV1) by 20% or more was considered as significant. Lung auscultation was performed by two observers simultaneously using a special stethoscope placed sequentially over the posterior right and left upper (interscapular region, 5 cm from the fourth thoracic vertebra) and lower lung zones (5 cm below the scapulae). Symptoms were recorded by the patients on a visual analogue scale. In 27 patients, the MCT was positive (MCT+) and in 27 patients it was negative (MCT-). Wheezes were identified at PD20 in 12 MCT+ patients while reduced BSI alone was found in 11 patients; in four patients, auscultation was normal. In 20 MCT+ patients, either wheezes, diminished BSI or both were heard, one to several steps before reaching PD20. In the MCT- group, wheezes were detected in two patients and diminished BSI in four. In MCT+ patients, the mean (+/-SD) perception of symptoms at end-challenge was 33% (+/-26), whereas in MCT- patients, it was 13.6% (+/-22). Complete inter-observer agreement was found in 95.7% of auscultations performed (Kappa coefficient = 0.846). Coupled to spirometry, lung auscultation may prove useful in airway challenge testing provided the concept is accepted that wheeze appearance and, by extension, an acute decrease in BSI, is as legitimate a manifestation of AH as a fall in FEV1.

[Asthma, rhinitis and urticaria following occupational exposure to cyanoacrylate glues]. / Asthme, rhinite et urticaire secondaires à l'exposition professionnelle aux colles cyano-acrylates.

Cyanoacrylate glues are more and widely used in the industry because of easy handling and great sticking power. These very volatile and chemically reactive glues may not only cause contact eczema, but also rhinitis and asthma. Nineteen cases of asthma have been reported to date. We report two new cases of occupational asthma as well as one case of urticaria, a clinical symptom not yet described, to our knowledge. In the three cases, diagnosis was made based on a compatible medical history and positive realistic exposure tests. The mechanism is still unknown, due to the physical properties of cyanoacrylate glues; in fact, it is not possible to perform prick tests or specific IgE measurements. Besides the usual preventive measures, maintaining a relative humidity greater than 55% seems to induce polymerization of free monomers of alkyl cyanoacrylate, thereby reducing their volatility. Rhinitis and asthma due to cyanoacrylate glue may receive compensation as occupational diseases in France.

[Study by questionnaire of the influence of weather conditions, particularly fog, on the symptomatology of asthmatic subjects]. / Etude par questionnaire de i'influence des conditions météorologiques, en particulier du brouillard sur la symptomatologie des sujets asthmatiques.

The role of fog in the symptomatology in asthmatic subjects has been assessed by a questionnaire concerning respiratory complaints linked to meteorological conditions and to non-specific irritant factors. In a population of 121 asthmatics (59 men and 62 women) 74.4% complained that fog was a factor aggravating their symptoms while only 3% of a group of 30 non-asthmatic subjects expressed discomfort during episodes of fog. The chemical analysis of fog during 32 episodes of local fog (pH, chloride, nitrate, sulphate, sodium, ammonia, potassium, magnesium, calcium) has shown a greater concentration of pollutants and greater acidity in the smaller particles (2-6 microns) which are able to penetrate the bronchial tree. This acidity could explain the role of fog in respiratory physiology. Certain authors have suggested that the aggravation of respiratory symptoms observed during peaks of pollution could be induced by aerosols containing sulphuric acid while others have described effects on respiratory function at the time of exposure to acid aerosols in asthmatic subjects but the results of the different studies have not all been concordant. Putting aside the role of the susceptible individual, other factors may intervene at the time inhalation of pollutants, notably the ambient humidity, the neutralising effect of endogenous ammonia and the synergystic effect between acid aerosols and atmospheric pollutants.