Injection and flow control system for microchannels.

In spite of considerable efforts, flow control in micro-channels remains a challenge owing to the very small ratio of channel/supply-system volumes, as well as the induction of spurious flows by extremely small pressure or geometry changes. We present here an inexpensive and robust system for flow control in a microchannel system, based on a dynamic control of reservoir pressures at the end of each channel. This system allows flow equilibration with a time constant smaller than one second, and is also able to maintain stable flux from stopped flow to many microl min(-1) range over several hours. It is robust to changes in ambient pressure and temperature. This system further includes a feature for sub-microliter sample injection during the experiment. We quantify flow control in elastomer and thermoplastic channels, and demonstrate the impact on one application of the system, namely the reproducible, automated separation of large DNA by electrophoresis in a self-organized magnetic bead matrix in a microchannel.

[Host factors in asbestos-associated disease. A study in twins (author's transl)]. / Manifestations thoraciques de l'amiante et génétique. A propos de deux paires de jumeaux univitellins.

Observations in two pairs of identical twins illustrate the importance of genetic factors in determining the outcome of exposure to asbestos in relation to pleural plaques and bronchogenic carcinoma. The first pair of twins, laggers with french railroad (S.N.C.F.), were discovered fortuitously, after only several years exposure, to have bilateral pleural plaques and calcification at the same site on the axillary and diaphragmatic surfaces. The second set of twins developed epidermoïd bronchial carcinoma : one at the right hilum, the other postero-basally on the right in 1969 and 1977 respectively. Both were in ship-building and each had been exposed to asbestos in the same yard for 20 years between 1945 and 1965. Radiographs showed left sided pleural calcification and reticular shadowing at the bases in the two cases. These observations show the role of the host in the generation of asbestos disease. They are in keeping with studies on the presence of certain tissue types (HLA B27, and HLA B8) in those with asbestosis and of non-specific auto-antibodies (anti-nuclear factor, rheumatoid factor) in asbestosis, silicosis and the idiopathic pulmonary fibrosis. The relation between genetic factors and asbestos-induced cancer is suggested by the variable susceptibility of different kinds of animals to carcinogenesis in response to asbestos and by the increased inductibility of the enzyme system Aryl-hydrocarbon-hydroxylase in subjects exposed to this air-born contaminant who develop pleural tumours and/or bronchitis. There are only two other publications of bronchial carcinoma in twins in the literature.

[Methodologic problems concerning pharmacology effect on bronchomotricity in asthma (Raw, V/V) (author's transl)]. / Problèmes méthodologiques pour apprécier l'action pharmacologique sur la bronchomotricité chez les asthmatiques à partir des mesures des Rva et des boucles V/V.

Study of spirometric, flow-rate and Raw modifications in three groups of 5 to 8 asthmatic patients (stage I or II) before and after acetylcholine and pneumallergen (dust) action is made. The same modifications were studied on the action of dust before and after a chemical protector effect. In two control groups the following parameters were verified: 1) the stability of Raw and V/V (normal subjects: 8); 2) the reproductibility of the acetylcholine bronchospasm, before and after the action of chemical protector (asthmatic patients: 11). Some considerations about the methodology in the practice of bronchomotricity data are submitted.

[Study of the regional distribution of inspired gas with radioactive tracers (author's transl)]. / Exploration de la distribution aérienne à l'aide de traceurs radio-isotopiques.

Two different techniques are utilized: aerosol with 198Au particles (size 0.5-15 micron) and different gaz mixtures (air; O2 20% + He 80+; O2 60% + N2 40%; O2 60% + He 40%) with 133Xe and registration of the regional distribution along a wash-in (upper, middle and basal) of every lung (gamma camer, computer, Polaroid photographs, scans), performed in three groups of subjects (normal: 5, bronchogenic carcinoma: 11 and chronic bronchitis: 5). Modifications of the airway distribution and blood gas data according to the technical approach (particularly, variations of densities and viscosities) are compared with results in normal subjects.

[Dermatoglyphics of subjects with bronchial cancers]. / Les dermatoglyphes des sujets atteints de cancers bronchiques.

Every high smokers are not able to make a lung carcinoma, on the over hand nonsmokers can be able to develop a bronchial carcinoma. It is possible that genetic factors can be involved in the occurrence of this carcinoma. Dermatoglyphic studies are one of the technics to appreciate this problem. The study was done upon 37 bronchial carcinoma and 51 lung diseases (European origin, only man, same age). There are some big differences upon: --The Cummins index: the right index as well as the left are higher in bronchial carcinoma than in controls, but it is significative only for the right one (p less than 0,05) (28,89 +/- 3,7 to 26,88 +/- 4,55). --The frequency of the ten fingerprints: the differences between lung carcinoma and controls are highly significative (p less than 0,01) for the whorls (22,7 to 34,9) and slightly significative (p less than 0,05) for the ulna loops (65,4 to 57,4), the other fingerprints (arch, radial loops) are quite the same in the two groups. The studies upon the other figures (TFRC and the position of the axial tri-radius) do not show any differences. It seems to us that the dermatoglyphic studies of men with bronchial carcinoma differ from controls (hospitalized for lung diseases). These population have the same dermatoglyphic structure than a control population from blood donors of Marseilles. The dermatoglyphic studies can be an aid to identify high risk people.

[Contribution to the study of the phagocytosing ability of broncho-alveolar macrophages in smokers and non-smokers (author's transl)]. / Contribution à l'étude du pouvoir phagocytaire des macrophages broncho-alvéolaire chez les fumeurs et les non fumeurs.

Broncho-alveolar macrophages were obtained by bronchial washing from 20 pairs of matched smokers and non-smokers. The following parameters were studied: phagocytosing ability of macrophages on silica in cell culture in the presence or absence of cotinin, a biocompound of nicotin; migration inhibitory factor (MIF), and power and level of alpha 1-antitrypsin in sera of patients. The results are reported as a function of absolute number of macrophages obtained, their viability, the amount of cigarettes smoked, and the action of cotinin. MIF was stronger in the smokers. There was no difference between the groups as far as power and level of alpha 1-antitrypsin are concerned. Cotinin provokes important lesions in the macrophages. The phagocytic power was not significantly different in smokers and non smokers, but the results were better in non-smokers.

[Respiratory function profile in scleroderma. 20 cases (author's transl)]. / Profil fonctionnel respiratoire dans les sclérodermies.

This study involved 20 patients, 13 female and 7 male, with a mean age of 49 years, suffering from localized (6 cases) scleroderma or generalized without Raynaud's syndrome (6 cas), with Raynaud's syndrome (6 cas) or acrosclerosis (2 cases). Respiratory function tests included study of volumes, flow rates, CO transfer (TLCO) and blood gases. There were 38% normal chest X-rays, 58% ventilatory disturbances (predominance of restrictive syndrome and decrease in (TLCO) was found in only 25% of cases. The authors emphasize the extent of pulmonary vascular lesions in these patients.

[Radiotherapy of localized inoperable bronchial squamous cell carcinoma (author's transl)]. / Radiothérapie et radiochimiothérapie des carcinomes bronchiques épidermoïdes localisés inopérables.

Authors have shown that in some favorable cases radiotherapy of localized bronchial carcinoma could give very good results. The study on the cases from 1960 to 1969 shows that authors have 8% of three years survival upon 105 patients who have been treated by 50 Grays or more in 5 weeks. The survival was better for the small cancers T2 than for the large ones. The study on the cases from 1970 to 1977 shows that to obtain 101 cases of squamous cell carcinoma (T2,4 -N0,2 -M0) authors were obliged to study 564 cases. The three years survival was 3,1% for carcinoma receiving more than 40 Grays/4 weeks. The survival is better for small cancer and for the cases without radiological mediastinal nodes. In conclusion, radiotherapy is the best treatment after surgery, limited disease can be cure, and iterative radiotherapy increases our results.

[Study of simultaneous dosage of carcino-embryonic antigen (C.E.A.) and beta 2-microglobulin in serum and pleural liquid (author's transl)]. / Apport des dosages simultanés de l'antigène carcino-embryonnaire (ACE) et de la beta 2-microglobuline dans le sérum et le liquide pleural.

Simultaneous dosage of carcino-embryonic antigen and beta 2-microglobulin was studied in serum and pleural liquid. Among the 20 patients with non-neoplasic infections, the carcino-embryonic antigen was not increased in the serum and only once at a border-line level in the pleura. The level of beta 2-microglobulin seems to be related to the number of lymphocytes in the pleural liquid (increase in 45% of the cases compared to 20% in the serum). Among the 31 cancer patients, carcino-embryonic antigen is increased in the serum of 36% of the cases and in the pleura of 48%. In 5 observations, the pleural levels were considerably increased compared with serum levels, suggesting the existence of a pleural metastasis. The beta 2-microglobulin is elevated in only 26% of the cases in the pleural liquid and in 13% in the serum. At the present state of knowledge, it therefore seems unnecessary to continue investigations concerning the beta 2-microglobulin. On the contrary, the pleural dosage of carcinoembryonic antigen could contribute to the diagnosis.

[Is long term medical follow up of tuberculous patients possible? (author's transl)]. / La surveillance hospitalière au long cours des tuberculeux est-elle possible?

Tuberculosis still remains a current disease, of difficult eradication as shown by numerous studies and epidemiological surveys. The authors studied 180 newly affected tuberculous patients admitted to Pr. Laval's department at Marseille and tried to discover why only 91 (50.6%) were still followed or could be traced 3 years after their first hospitalization. Five parameters were studied: origin, sex and age, living area, socio-economical data (change of address, lack of accomodation, profession), tobacco and alcohol addiction. No significant part was played by nationality, living area, or profession. On the other hand, changing of address, chronic tobacco and alcohol addiction were the factors responsible for loosing sight of the patients. An attempt to define this tuberculous patient, which would not be followed up for long, gave the picture of a 40 to 45 years old man, living in a hotel or with no fixed accomodation, smoking more than 20 cigarettes a day and drinking. Such a profile of a tuberculous patient should increase the watchfulness over likely ones.

[Treatment of rhabdomyosarcoma in mice C3H/He by Co 60 and hyperbaric oxygen (author's transl)]. / Traitement du rhabdomyosarcome chez la souris C3H/He par cobalthérapie sous oxygène hyperbare.

UNLABELLED: Experimental study of rhabdomyosarcoma with successive transplantation upon C3H/He mice, treated by irradiation (Co 60) and combined irradiation-hyperbaric oxygen (HBO), dating from 3, 14 and 15 days after transplantation. The data (tumor volume evolution, histological modifications, pulmonary metastases) are compared with controls. CONCLUSIONS: curative radiotherapy depends on starting treatment as soon as possible with or without HBO. After the 14th day, sensitisation to combined HBO and C60 is seen. The extension of pulmonary metastases is a function of tumor growth. Paradoxically metastases were less frequent after HBO only and more frequent after HBO-Co 60.

[Smoking habit at school. First habit at school. First results of a survey done in Marseille and its suburbs (author's transl)]. / Le tabagisme scolaire. Premiers résultats d'une enquête réalisée dans l'agglomération marseillaise.

The authors report the first results of a transversal survey done from the end of November 1976 to the end of April 1977 in 4 secondary schools (CES, CEG) in Marseille and its suburbs. 1.795 children, between 11 and 15, in the first and fourth form, filled up a questionary inquiring into their smoking habits and consumption. Already a certain number of results can be drawn: --in this group of children, mostly girls (926 G/882 B) 181 were regular smokers (10,07%); --among these smokers, 70 smoked every day (38,6%), 60 smoked more than a packet a week (33%), finally 122 inhaled smoke; --they acquired the habit of smoking regularly between the age of 14 and 15, in the 3rd and 4th forms, as there was only 9,4% of smokers in the 3rd and 19% in the 4th form; --finally, parents seem to play a fundamental inducing part in this habit, as among smoking children 32.8% have parents both smoking, 41% a smoking mother, 71.2% a smoking father, while for non smokers the percentage were respectively of 19.9%, 24.9% and 54.3%.

Evaluation of the distribution of air and blood in emphysema patients using radioisotopic tracers.

Continuous recording of the respiratory cycle with the simultaneous or sequential radionucleic exploration (gamma camera) of ventilation (133Xe) and perfusion (MAT-99) was performed to determine the V/Q index in regional areas (Polaroid photography, mini-computer, memory visualization system, Benson incremental tracer, etc.) from the level of 1,024 points. An average ratio per sector was calculated and only three median sectors were retained. The wash-in and wash-out curves were traced by computer, and the calculation of the average T 1/2 for the different compartments of each median sector (apex--middle and base) was done in about 22 observations: in 18 diffuse emphysema, 11 of which were associated with giant cystic emphysema (spirometric, plethysmographic and radiographic data), T 1/2 values were greater than those of normal subjects (compartments C1 and C2) in diffuse emphysema and can become indefinable in zones of cystic emphysema. The values of the index V/Q approach the normal in diffuse emphysema with a tendency toward equalization of the ratios from the apex to the base. Extremely large divergence is observed in the elevated V/Q ratios in cystic emphysema.