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Although 210 chemically different polychlorinated dibenzo-p-dioxin and dibenzofuran congeners can be produced during combustion, it is currently believed that fewer than 20 are toxic enough to warrant monitoring. SRI is developing a continuous emissions monitor to study the emission levels of these most toxic dioxins, leading eventually to an improved understanding of the formation of these molecules and to improved means of monitoring and control. We report here the first results of performing congener-specific detection for two dichloro dibenzo-p-dioxins present in low ppt concentrations in a mixture using the supersonic jet/resonantly enhanced multiphoton ionization time-of-flight mass spectrometer technique. In addition, we present preliminary data on the detection of chlorinated aromatic compounds using a two-color REMPI scheme with the same instrument.

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The need for a continuous monitor for environmentally important pollutants at realistic [parts-per-trillion (parts in 10(12))] concentrations measured in real time (minutes) is widely recognized. We developed an instrument that is based on supersonic-jet expansion and cooling, followed by resonantly enhanced multiphoton ionization (REMPI) into a mass spectrometer. This approach furnishes the dual selectivity of narrow-band tuned laser absorption and mass analysis. We initiated a spectroscopic characterization of the jet's collisional cooling behavior to optimize the instrument's sensitivity and selectivity, made measurements of several aromatic compounds (including polychlorinated dioxins) by use of a one-color REMPI scheme, and demonstrated a two-color excitation scheme.

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NASA: Potential conflicts between the use of weightlessness countermeasures during space flight and research into the physiological effects of weightlessness are examined. Research and medical operations goals are presented and experiences reviewed. Anticipated countermeasures for the International Space Station and possible solutions to the conflicts are described.^ieng

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International cooperation in life sciences, as in any other of the space research fields, takes place at two distinct levels: scientist to scientist, or agency to agency. This article is more concerned with the agency to agency level, which involves the arrangements made between two partners for the flying of experiments and/or hardware on space missions. International cooperation is inherent to the European Space Agency (ESA), since it consists of 13 member states (Austria, Belgium, Denmark, France, Ireland, Italy, the Netherlands, Norway, Spain, Sweden, Switzerland, United Kingdom, and West Germany) and one associated member, Finland. ESA also has special cooperative arrangements with Canada. Life sciences research in ESA is carried out within the Microgravity Research Program, an optional program to which member states (in this case all but Austria and Ireland) contribute "a la carte," and receive their "share" accordingly. Therefore, many of the activities are naturally linked to international arrangements within the member states, and also to arrangements between the agencies, with life sciences being the dominant activity between NASA and ESA.

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Using the "mechanical oscillator technique," the mass density of antecubital venous blood and plasma samples was measured 5-20 times in order to study the influence of postural changes (gravity dependence) on human blood mass density with 0.01 g.L-1 precision, while performing tilt table tests in 17 men. Hemoglobin concentration was measured in 10, and hematocrit in all subjects. Postural fluid shifts were mirrored by accompanying changes in all variables. Blood density (BD) was monitored continuously in five additional experiments from one vein each using two independent densitometers. There were linear relations (p less than 0.01) between all possible combinations of BD, plasma density (PD), blood hemoglobin concentration (Hb), and hematocrit (Ht). Hb can be directly computed from BD (range +/- 10%); the accuracy of Ht determinations from BD increases (range +/- 0.02) if the individual erythrocyte density (ED) and the sample PD are used for calculation. ED was calculated and did not change with body position. ED values of different persons ranged between 1085 g.L-1 and 1095 g.L-1 and did not vary in 15 out of 17 individuals with time (5-75 d). We conclude that ED is closely regulated to an individual set point, that Ht can be computed from BD with higher accuracy if the individual ED and the actual PD values are known, and that BD allows for direct Hb calculation. On-line BD monitoring can be performed with high precision and reveals the individual time-course of spontaneous and postural capillary fluid shifts.

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With the advent of Europe's commitment to contribute the European Space Agency (ESA) to the NASA Space Transportation System (STS) by means of the Spacelab programme, a new area for research opportunities on Life Sciences has been created for the European scientific community. Although considered as a young and new discipline, the goals of Life Sciences research in space had soon been defined by the ESA advising Life Sciences Working Group in the beginning of 1977. The programme proposals of the various subdisciplines concentrated on the advantageous use of the microgravity environment, to study in more depth the gravity relevance of biological systems. It included, however, also the use of other factors during space flight which cannot be reproduced or adequately simulated on the ground: cosmic radiation in its total spectrum, particularly HZE particles, solar and UV radiation, vacuum, and the combination of radiation and weightlessness, etc. On this basis, call for proposals in the various subdisciplines resulted in experiments also in the field of radiation biology which were flown on the Spacelab 1 mission and which were selected for later missions. In particular, ESA is providing the science community with mission opportunities on Spacelab, either European or International, with platforms to be launched by STS, and with so called multi-user facilities (e.g. Biorack). Typically, the experiments will be the responsibility of the scientists, the integration and mission phase the responsibility of ESA. Both mission definition and experiment selection rests with the ultimate decision of the responsible ESA Programme Board. A further description of missions envisioned, the Spacelab facility, platforms, multi-user facilities and areas of research applicable to radiobiology will be given. ESA's continuing interaction with the scientific community through the Life Sciences Working Group, and the advice on future programmes will be stressed as a vital factor contributing to a European Life Sciences Programme in Space.

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The results of a prospective study comparing the rigid and flexible fibreoptic bronchoscopic techniques in the diagnosis and assessment of bronchial carcinoma are reported. One hundred and nine patients underwent fibreoptic bronchoscopy and these were compared with a similar group of 111 patients in whom the rigid bronchoscope was used. Bronchoscopic diagnosis of malignancy was achieved in 73.4% of patients in the fibreoptic group and in 73% using the rigid bronchoscope.

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Lung cancer of the right upper lobe not infrequently invades the right lower trachea. A tracheobronchoplastic procedure is described that makes it possible to reconstruct the tracheal defect after excision of the growth, while preserving the uninvolved lobes of the right lung.

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Six hundred and sixty-three patients with bronchial carcinoma underwent lung resection after mediastinoscopy had shown no apparent involvement of the mediastinal nodes. The average age was 65 years. Ninety-five percent of the patients could be followed up. A resectability rat of 97.3% was achieved. The operative mortality was 5.5%, irrespective of whether a lobe or whole lung was removed. The 5 year survival rate could be determined in 417 patients. Staging of the disease was done at the time of operation, which makes is possible to analyze the factors influencing survival. Mediastinal node involvement is associated with a high operative mortality and a very poor outlook after resection. Selection by routine preoperative mediastinoscopy has not improved the long-term survival rates as compared with other series in which such selection was not carried out. This confirms that the biological behavior of the tumor and not the initial selection determines the long-term survival. The prognosis is very grave with mediastinal node involvement.

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Seven children, aged 4 months to 10 years, with bronchial compression due to tuberculous hilar lymphadenitis have been treated surgically since 1974. The indications for surgical treatment were lack of response to chemotherapy and in particular the development of respiratory distress. Excision or curettage of the affected nodes was found to be a safe and sure method of relieving the acute symptoms and preventing permanent damage to the lung.

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This paper presents a comparative study of two methods of fundoplication, a Belsey-like procedure and a Nissen-Rossetti operation in the management of 283 cases of hiatal hernia from 1962 to 1974. The methods, history, and preoperative findings are described, and the mortality and morbidity rates, particularly related to recurrence, are discussed. A short historical review is included in the discussion, which also deals with the anatomic and physiologic factors thought to be involved in the maintenance of the competence of the cardia. The author's reasons for preferring a Nissen operation are outlined. The management of peptic stricture and of shortening due to periesophagitis by modification of this technique is described.

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