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Medical assessment of Swedish smoke diving firefighters includes cardiac evaluation by maximal exercise testing with ECG recording. The exercise ECG procedure for firefighters was introduced in 1986, and remains consistent in the recently updated guidelines from 2019. Exercise ECG is a non-invasive and easily available method for detection of chronic coronary syndromes, but due to the declining population risk in high-income countries, its ability to accurately detect disease has decreased. Thus, the clinical relevance of exercise ECG in firefighters is questioned and the pre-duty medical assessment requires modernization.

Objectives. Exercise electrocardiogram (ExECG) in low risk populations frequently generates false positive ST depression. We aimed to characterize factors that are associated with exercise-induced ST depression in asymptomatic men without coronary artery disease. Design. Cycle ergometer exercise tests from 509 male firefighters without imaging proof of significant coronary artery disease were analysed. Analysed test data included heart rate at rest before exercise, and workload, blood pressure, heart rate, ST depression and ST segment slope at peak exercise. ST depression of amp;gt;0.1 mV was considered significant (STdep). With a mean follow-up of 6.1 +/- 1.7 years, medical records were reviewed for cardiovascular diagnoses, hyperlipidemia and diabetes. Logistic regression analysis was used for risk assessment. Results. In total, 22% had STdep in amp;gt;= 1 lead. Subjects with STdep were older than those with normal ExECG (p amp;lt; .001). Downsloping STdep was more common in extremity leads (9%) than in precordial leads (2%). STdep was categorized according to location (precordial/extremity) and slope direction into eight categories. Larger age-adjusted heart rate increase predicted STdep in seven categories (p amp;lt; .05). Age-adjusted peak heart rate correlated with STdep in five categories, predominantly where the ST slope was positive. Peak blood pressure and exercise capacity were both associated with STdep in few categories. We found no association between STdep and hypertension, hyperlipidemia or diabetes (all p amp;gt; .05). Conclusions. In asymptomatic men with a physically demanding occupation and no coronary artery disease, both age and heart rate response were associated with ST depression, whereas common cardiovascular risk factors, blood pressure response and exercise capacity were not. Funding Agencies|County Council of Ostergotland, Sweden [LIO-711261]; ALF grant [700731]

The fitness of firefighters is regularly evaluated using exercise tests. We aimed to compare, with respect to age and body composition, two test modalities for the assessment work capacity. A total of 424 Swedish firefighters with cycle ergometer (CE) and treadmill (TM) tests available from Jan 2004 to Dec 2010 were included. We compared results from CE (6 min at 200 W, 250 W or incremental ramp exercise) with TM (6 min at 8° inclination, 4·5 km h-1 or faster, wearing 24-kg protective equipment). Oxygen requirements were estimated by prediction equations. It was more common to pass the TM test and fail the supposedly equivalent CE test (20%), than vice versa (0·5%), P

Detecting fluid imbalance in patients with chronic heart failure can be challenging. Use of a pocket-sized ultrasound device (PSUD) in addition to physical examination can be helpful to assess this important information.To evaluate the feasibility for nurses without prior experience of ultrasonography to examine fluid imbalance by the use of a PSUD on heart failure patients.Four heart failure nurses and an expert cardiologist participated. The nurses underwent a four-hour PSUD training programme. One hundred and four heart failure outpatients were included. The examinations obtained information of pulmonary congestion, pleural effusion and the diameter of the vena cava inferior.Examinations took nine minutes on average. In 28% and 14% of the patients, pulmonary congestion and pleural effusion respectively were found by the nurses. The sensitivities and specificities for nurses' findings were 79% and 91%, and, 88% and 93% respectively. The inter-operator agreement between the nurses and the cardiologist reached a substantial level (kappa values: 0.71 and 0.66). The inter-operator agreement for vena cava inferior reached a fair level (kappa value=0.39). Bland-Altman plots of the level of agreement revealed a mean difference of vena cava inferior diameter of 0.11 cm, while the 95% lower and upper limits ranged from -0.78 cm to 1.00 cm.After brief training, heart failure nurses can reliably identify pulmonary congestion and pleural effusion with a PSUD. Assessment of vena cava inferior was less valid. PSUD readings, when added to the history and a physical examination, can improve nurse assessment of fluid status in patients with heart failure.

More than 50 % of patients seeking hospital care because of chest pain are diagnosed as having “non-cardiac” symptoms [1, 2]. Many patients are discharged without knowing the cause of their chest pain [3, 4]. Patients with noncardiac chest pain experience psychological distress [5, 6] and use healthcare resources to a great extent, leading to high healthcare costs [7–11]. Despite reassurance [12], many patients think they have an undetected cardiac disease and avoid activities that they believe might be harmful to the heart [13, 14]. Cardiac anxiety is common in patients with recurrent non-cardiac chest pain [6], leading to a vicious cycle, as it leads to maintenance of both anxiety and pain and secondary avoidance of physical activity [15, 16]. Targeting cardiac anxiety with psychological interventions might break the vicious circle and improve patient outcomes. Patients need to evaluate the way they perceive and handle their chest pain; this can be achieved using cognitive behavioural therapy (CBT) [17]. There is strong support for face-to-face CBT in the treatment of mild and moderately severe states of anxiety and depressive disorders [18–20] and non-cardiac chest pain [21, 22]. Previous face-to-face CBT studies [12, 23–26] have shown positive effects on chest pain frequency, activity avoidance, anxiety, and depression among patients with non-cardiac chest pain. Face-to-face CBT can be effective when delivered by experts, but it is time-consuming [27, 28] and therefore not easy to provide to everyone. Internet-delivered CBT seems as a good alternative since it is cheaper, is not time dependent, and requires less therapist involvement [28], and could therefore be given to more patients. Therapist-guided Internet-delivered CBT does not differ from face-to-face treatment with regard to treatment effects [28–30], regardless of the background of the therapist guiding the Internet-delivered CBT [18, 31–33]. As concluded by Sharp et al. [34], Internet-delivered CBT might be a means to increase access to psychological treatment to patients with different chronic somatic conditions, although more research is needed to establish the feasibility and efficacy of Internet-delivered CBT for such populations. However, no Internet-delivered CBT programs have been tested in patients with non-cardiac chest pain. Our hypothesis was that a guided Internetdelivered CBT program targeting cardiac anxiety can help patients modify their beliefs about chest pain, change their cognitive and behavioural strategies, and give them tools to handle their chest pain. Furthermore, a four-week treatment would be preferred by the patients and easier to implement in the healthcare settings than a longer faceto-face treatment. The purpose of the study was to test the feasibility of a short guided Internet-delivered CBT program and explore the effects on cardiac anxiety, fear of body sensations, depressive symptoms, and chest pain in patients with non-cardiac chest pain, compared with usual care.

Significant faunal changes reported fromrecent, coastal environments,which are not directly influenced by urban and industrial impact, are rarely seen. In Gullmar Fjord on the Swedish west coast, a significant foraminiferal fauna change occurred in connectionwith severe low-oxygen conditions that evolved in thewinter of 1979/1980. A foraminiferal fauna marked by common Skagerrak–Kattegat species, which had previously characterised the deep fjord basin, was replaced by the opportunistic, low-oxygen tolerant species Stainforthia fusiformis (Williamsson). To study this phenomenon further we performed stable oxygen and carbon isotope analyses on the indicator species itself, S. fusiformis, both on specimens from sediment cores representing approximately the last 85 years and on living (stained) individuals taken from a transect across the deep fjord basin. Our purpose was to detail how and why S. fusiformis, came to dominate the fauna. The oxygen isotope results suggest that salinities and temperatures in the deep basin have been relatively constant over the last c. 85 years, while the carbon isotopes show a significant change towards more negative values in association with the faunal shift of 1979/1980. The combined results from both the cores and the surface sediments suggest that S. fusiformis did not inhabit the deep basin until 1980. Before then, almost all specimens of S. fusiformis were small sized and their carbon isotope values suggest they were re-deposited shallow-water specimens that had been transported down to the central, deep basin as part of a suspension load. After a major faunal extinction in 1979–1980, S.fusiformis of all sizes suddenly appeared in large numbers and their carbon isotopic values were similar to the signal from registered in the recent, living fauna within the deep basin. This suggests that the opportunistic S. fusiformis established itself in the deep basin as a consequence of the severe low-oxygen event and the faunal crash of the previously dominating Skagerrak–Kattegat fauna. (Less)

Stable isotopes of bulk sediment and well preserved tests of planktonic and benthic foraminifera from midlatitude NE Atlantic DSDP Site 551 (Goban Spur) provide the first estimates of carbon isotope gradients within the water column at a lower bathyal site during the Cenomanian/Turonian boundary interval (CTBI). The CTBI carbon isotope excursion is prominent (up to 2parts per thousand shift in delta(13)C) in the bulk (coccolith) signal, but less pronounced (approximately 0.5 parts per thousand shift in delta(13)C) in planktonic and benthic foraminifera. This difference indicates a very steep (13)C gradient in the upper water column and a very efficient biological pump during the CTBI carbon isotope excursion. We suggest significantly increased seasonal primary production in the uppermost water column with an enhanced shallow water chlorophyll maximum as a cause for this steep carbon isotope gradient. Deep-water and surface-water temperature changes during the CTBI are estimated using benthic and planktonic foraminiferal oxygen isotopes. Warm deep-water masses (13-16degreesC) and a low temperature gradient within the water column prevailed in the late Cenomanian. Additional warming (approximately 2degreesC for both surface and deep water) occurred in the latest Cenomanian prior to CTBI black shale deposition. This pattern of CTBI black shale deposition during a temperature maximum is also evident at two low latitude locations (ODP Site 1050, Blake Nose and Tarfaya, southern Morocco). (C) 2003 Published by Elsevier B.V.

Koljö Fjord and Havstens Fjord on the Swedish west coast are, like many silled fjords in Scandinavia, characterized by strong stratification and stagnant bottom water with periodically occurring low-oxygen and anoxic conditions. High organic production together with a stable water-column, very low tidal activity and existence of the sill create an ideal foundation for low-oxygen conditions to develop. The aim of this study was to find out how the fjord environments developed during the later part of the Holocene and, especially, how and when the low-oxygen conditions evolved. To achieve these goals, sediment cores were dated (210Pb and 14C) and x-rayed, the distribution of benthic foraminifera was analysed and their content of the stable isotopes d18O and d13C was investigated. In both fjords, the climate proved to be of importance for the environment and it seems that increased freshwater runoff increased the primary production between 500 bc and ad 500. Increasing freshwater runoff not only increased primary production but, at least since ad 1880, also made the water stratification stronger and the deep water more stagnant. Stagnant conditions are the main cause of the development of periodic anoxia and formation of laminated sediments in Koljö Fjord from ad 1930 to 1980 and in Havstens Fjord from ad 1950. In Koljö Fjord, the isostatic land rise and the shallow sill are the most important reasons for a general change from an almost normal saline deep-water environment to a brackish environment in ad 500. At that time the sill depth passed the pycnocline mean depth of 15 m. For Koljö Fjord, this is a threshold value of the depth for the quality of the deep water, marine or brackish.

The ability of neutrophils to sense and move to sites of infection is essential for our defense against pathogens. For motility, lamellipodium extension and stabilization are prerequisites, but how cells form such membrane protrusions is still obscure. Using contrast-enhanced video microscopy and Transwell® assays, we show that water-selective aquaporin channels regulate lamellipodium formation and neutrophil motility. Addition of anti-aquaporin-9 antibodies, HgCl2, or tetraethyl ammonium inhibited the function(s) of the channels and blocked motility-related shape changes. On human neutrophils, aquaporin-9 preferentially localized to the cell edges, where N-formyl peptide receptors also accumulated, as assessed with fluorescence microscopy. To directly visualize water fluxes at cell edges, cells were loaded with high dilution-sensitive, self-quenching concentrations of fluorophore. In these cells, motile regions always displayed increased fluorescence compared with perinuclear regions. Our observations provide the first experimental support for motility models where water fluxes play a pivotal role in cell-volume increases accompanying membrane extensions.

Venous congestion is common in patients with chronic heart failure (HF). We used a pocket-sized ultrasound imaging device (PID) to assess the patients' congestive status and related our findings to prognosis.One hundred four consecutive outpatients from an HF outpatient clinic were studied. Interstitial lung water (ILW), pleural effusion (PE), and the diameter of the inferior vena cava (VCI) were assessed with the use of a PID. ILW was assessed by demonstration of B-lines (comet tail artifact (CTA). Out of the 104 patients, 28 had CTA and 8 had PE. Median VCI diameter was 18 mm (interquartile range 14-22 mm). Each of these parameters correlated weakly (r = 0.26-0.37; P.05) with the HF biomarker N-terminal pro-B-type natriuretic peptide (NT-proBNP). During the median follow-up time of 530 days, 18 hospitalizations and 14 deaths were registered. Findings of CTA, PE, or both increased the risk of death or hospitalization (hazard ratio 3-4; P.05). After adjustment for age, cardiac systolic function, and NT-proBNP, this difference remained significant for CTA alone and CTA + PE combined, but not for PE alone.With the use of a handheld ultrasound device, signs of pulmonary congestion could be demonstrated. When found, these had a significant prognostic impact in clinically stable HF.

Since the late 1970s, Scandinavian waters have been extensively investigated for human-induced marine pollution, especially marine eutrophication, oxygen deficiency in bottom waters and subsequent benthic mortality. The most serious oxygen deficiencies are noted in the sill fjords along the Swedish west coast, in southern Norway and in large areas of the southern Kattegat and Baltic Sea. One of these sill fjords, Koljo Fjord, is located on the Swedish west coast. This fjord is characterised by frequently occurring episodes of hypoxia/anoxia which last for months or even years. Sediments are laminated and the fjord is generally regarded as seriously affected by human-induced eutrophication. We detail the environmental development of a well-documented fjord by combining high resolution sediment records with long hydrographical and meteorological instrumental data, and we present ultra high-resolution sediment information together with long-term instrumental records of air-temperatures, NAO indices and hydrography from Koljo Fjord. These data show, in contrast to the current opinion focusing on anthropogenic eutrophication, that natural causes are the most important factors controlling the marine environment in this sparsely populated area. Natural variables concerned are fjord physiography, weather and hydrography (including the macro-nutrients DIN and PO 4 -P), sediment laminations and organic carbon. Interactions between fjord physiography, weather and hydrography regulate the possibility for water exchange and deep-water renewals. The present study points to the importance of natural causes for the environmental status of sill basins and semi-enclosed areas along the west coast of Sweden.

Living (stained) benthic foraminifera were studied in the deepest part (116 m) of the classical marine study area, the Gullmar Fjord on the Swedish west coast. This is a silled fjord with a strongly stratified water column where stagnant conditions temporarily develop in the deeper parts. The aim of this study is to determine how the living foraminiferal assemblage develops with seasonal variations in bottom water hydrography and primary production in the surface water. From August 1993 to December 1994, monthly hydrographic and oxygen measurements were made. Parallel undisturbed sediment cores were taken using a Multiple-corer. Foraminifera from the >63 μm fraction were stained with Rose Bengal to separate living from dead specimens. Monthly values of the surface water chlorophyll a content were also available and give a measure of the primary production. During spring 1994 the dominant foraminiferal species, Stainforthia fusiformis, multiplied its population size by seven times during one month as a consequence of food input from the spring phytoplankton bloom. The abundance of this species correlates positively with the surface water chlorophyll a content. Populations of several other species also increased during the spring of 1994. A deep-water inflow in February 1994 may have triggered reproduction of several foraminiferal species, recognized as a temporary population decline. We also compared our results with Hoglund’s (1947) foraminiferal study, performed in the same area in the summer of 1927. We found that a major alteration trending towards a more opportunistic low oxygen tolerant fauna has occurred since then.

Tri-n-butyltin (TBT) has been used in the marine environment as a toxic agent in antifouling paints, but unfortunately it also has negative effects on non-target organisms in the environment. In this study, intact coastal sediment was exposed for seven months to three levels of TBT corresponding to nominal additions of 0.00, 0.02 and 2.00 nmol TBT per g dry sediment. This paper presents the first attempt to find out how living benthic foraminifera respond to TBT. Increased foraminiferal abundance in the 0.02 nmol mesocosm could be an effect of decreased predation (competition), since other representatives of meiofauna and macrofauna tended to be less tolerant to TBT. Increasing toxicity in the most contaminated mesocosm group (2.00 nmol) resulted in a less abundant foraminiferal population suggesting that TBT affects the foraminiferal community.

The deep Gullmar Fjord on the Swedish west coast may be subject to a trend of decreasing oxygen content of the bottom-water. Due to a non-uniform frequency of oxygen measurements before and after 1980, and small differences in the minimum concentrations, it is difficult to assess with certainty if this is true or not. We have used benthic foraminifera from three ultra-high resolution sediment records to try to find out if such a trend exists. The sediment records comprise the time between 1930 and 1996, with an almost year-based temporal resolution. The foraminiferal records show a significant change in faunal composition during the mid-1970's when it altered from a common Skagerrak fauna to an assemblage characterized by an opportunistic, low oxygen tolerant species; Stainforthia fusiformis. This species is an indicator of low oxygen environments of many Scandinavian fjords. The timing of this faunal change coincides with one of the first recorded severe low oxygen events in the Gullmar Fjord in the winter of 1973/1974. The change suggests that the Gullmar Fjord has actually been subject to a decrease in bottom-water oxygen concentrations. The reason for this change is not clear but here, for the first time, we present sediment records that suggest that there is a causal relation between variations in the North Atlantic Oscillation (NAO) indices and the marine environment. In the early 1970s the NAO-indices altered from a mainly negative phase towards a mainly positive period which is still ongoing. Positive NAO-indices (winter values) in the Skagerrak region are generally marked by westerly winds which normally prevent the exchange of bottom-water in the fjords, i.e., the oxygenation of the sea floor and the supply of oxygen to benthic life.

The Koljo fjord on the Swedish west coast is a silled fjord characterised by strong stratification and stagnant bottom water, with periodically occurring hypoxic or anoxic conditions. In the Koljo fjord, renewal of the deep water generally occurs during winter. This study investigates how living benthic foraminifera react to hydrographic variations, periodic oxygen deficiency and variations in primary production. A series of monthly hydrographic measurements was made from August 1993 to December 1994, combined with sediment sampling along a (12–43 m) depth transect at five different sites. Monthly values of surface chlorophyll-a were available. Two periods of hypoxia to anoxia with one intervening period of oxic conditions, together with two autumn phytoplankton blooms and a spring phytoplankton bloom, made it possible to achieve the aims of this study. Below the pycnocline, three foraminiferal species: Elphidium excavatum clavatum , Elphidium incertum and Elphidium magellanicum represented more than 95% of the fauna. When oxygen content was very low, the foraminiferal fauna decreased but did not die out completely. A deep-water inflow in January 1994 caused the oxygen content to rise, but the foraminiferal population did not start to grow until three months later when the spring phytoplankton bloom sedimented out. Under oxic conditions, food availability seemed to limit the foraminiferal population. In itself, a very high organic content in the sediments does not seem to be a suitable food source; it is more likely that fresh phytoplankton is a potent food for these foraminifera. Reproduction of E. excavatum clavatum and E. incertum seems to have been triggered by increased food supply and sudden fluctuations in hydrographic variables. These foraminifera appear to grow from juvenile to adult in less than a month.

RealTimeTalk (RTT) is a design framework for developing distributed real-time applications with both hard and soft requirements. The framework supports design via hierarchical decomposition. We believe that object-orientation is the best way to go about structuring a problem, hence the RTT language is based on Smalltalk with an analysis frontend to infer type information for run-time safety, and to yield more precise estimations of execution times. Unlike most real-time systems, RTT does not force the designer to embed constructs for timing requirements, communication, and synchronization in the code. Rather, such information is specified on a higher level of abstraction using graphical tools. This not only keeps the code “clean” but also simplifies timing analysis and resource allocation. A comparison with other real-time systems concludes the paper.

The stimulus formylmethionyl-leucyl-phenylalanine (FMLP) interacts with neutrophils and generates signal(s) in the cells that induces mobilization of the secretory vesicles as well as activation of the superoxide anion/hydrogen peroxide generating NADPH-oxidase. Binding, at 15 degrees C, of FMLP to its neutrophil surface receptor is followed by an association of the ligand-receptor complex to the cell cytoskeleton, and this association occurs concomitant with a desensitization of the cells with respect to activation of the NADPH-oxidase. Other stimuli can still activate the oxidase (in fact even induce a primed response), indicating that the observed phenomenon is stimulus specific and could not be accounted for by an effect on the oxidase itself, but rather that the association of the ligand-receptor complex to the cytoskeleton eliminates the capacity of the complex to generate the signal(s) that activates the NADPH-oxidase. The cytoskeleton associated ligand-receptor complex generates, however, the signal(s) responsible for mobilization of the secretory vesicles, to the plasma membrane, and this mobilization occurs without any increase in the intracellular concentration of free Ca2+.

The effect of intracellular free Ca2+ ([Ca2+]i) on the intracellular aggregation of Chlamydia trachomatis serovars L2 and E in McCoy and HeLa cells is investigated. Loading the cells with the Ca2+ chelator MAPT/AM (1,2-bis-5-methyl-amino-phenoxylethane-N,N-n'-tetra-acetoxymethyl acetate), thereby decreasing the [Ca2+]i from 67 to 19 nM, decreased the number of cells with a local aggregation of chlamydiae in a dose-dependent manner. Neither the attachment nor the uptake of elementary bodies (EBs) was, however, affected after depletion of Ca2+ from the cells. There was no significant difference in the level of measured [Ca2+]i between infected and uninfected cells. Reducing the [Ca2+]i also significantly inhibited chlamydial inclusion formation. Differences in the organization of the actin filament network were observed in response to [Ca2+]i depletion. In Ca(2+)-depleted cells, where few EB aggregates were formed, few local accumulations of F-actin were observed in the cytosol. These results suggest that the aggregation of EBs in eucaryotic cells requires a normal homeostasis of intracellular Ca2+. By affecting F-actin reorganization and putatively certain Ca(2+)-binding proteins, [Ca2+]i plays a vital role in the infectious process of chlamydiae.

To design Hard Real-Time systems we require predictable time behaviour. With Hard Real-Time systems we mean systems where all tasks have to meet their deadlines. One way to satisfy the deadline requirements is to determine the time behaviour of the Real-Time kernel and the hardware platform. It is difficult to build a time model of todays complex hardware and the software for the Real-Time kernel. An easier way is to test the time performance of the Real-Time kernel on the hardware with small measurement tasks. This article describes an approach of measuring and analyzing the execution time (performance) for the Real-Time kernel on a hardware platform. The approach is to measure the Real-Time kernels performance when it is running on the hardware.

Quantification of lung ultrasound (LUS) artifacts (B-lines) is used to assess pulmonary congestion in emergency medicine and cardiology [1,2]. We investigated B-lines in relation to extravascular lung-water index (EVLWI) from invasive transpulmonary thermodilution in septic shock patients. Our aim was to evaluate the role of LUS in an intensive care setting.

The use of state-of-the-art real-time techniques in industry remains infrequent. The reason for this, we believe, is three-fold: (1) the lack of commercially available tools, (2) the lack of methodologies based on real-time theory throughout the complete development process, and (3) the lack of competence in real-time theory among industrial practitioners. In this paper, we present a case study of the introduction of state-of-the-art real-time techniques in industry. The case study was performed as a collaboration between Malardalen University and the industrial partners Volvo Construction Equipment Components AB (VCE) and TietoEnator ArosTech AB. VCE develops computer control systems for construction equipment vehicles, such as wheel loaders, graders and articulated haulers. TietoEnator ArosTech is a firm of consultants with recognized competence in the field of embedded real-time systems. The contribution of this paper consists of the findings from the introduction of a method and real-time techniques into an industrial project. The main result reported can be summarized as "people (not paper) transfer technology".

Upon contact with the eukaryotic cell, Yersinia pseudotuberculosis increased the rate of transcription of virulence genes (yop), as determined by in situ monitoring of light emission from individual bacteria expressing luciferase under the control of the yopE promoter. The microbe-host interaction triggered export of LcrQ, a negative regulator of Yop expression, via the Yop-type III secretion system. The intracellular concentration of LcrQ was thereby lowered, resulting in increased expression of Yops. These results suggest a key role for the type III secretion system of pathogenic bacteria to coordinate secretion with expression of virulence factors after physical contact with the target cell.

The mobilization of intracellular calcium plays an important role in regulating neutrophil activation. With this in mind we investigated the effect of intra- and extracellular calcium on the ability of human neutrophils to kill complement-opsonized Staphylococcus aureus. We found that a rise in intracellular calcium is necessary for efficient killing of phagocytosed S. aureus. In the presence of extracellular calcium, killing of ingested bacteria in calcium-buffered neutrophils compared with normal cells was slightly reduced. Calcium buffering had no effect on phagocytic uptake by the neutrophils, but did decrease the generation of toxic oxygen metabolites, measured as chemiluminescence (CL). In non-depleted and calcium-depleted cells, removal of extracellular calcium did not affect ingestion but did cause a marked decrease in the ability to kill the bacteria. In parallel, the CL response was substantially reduced or completely blocked. These data show that calcium is not a prerequisite for phagocytosis of S. aureus by human neutrophils, but does play a vital role in the post-ingestion killing of the bacteria by regulating the generation of toxic oxygen metabolites.

During the last decade, image-processing techniques have been introduced as a valuable tool in biologically oriented research. In combination with novel fluorescent probes, these techniques permit assessment of subcellular distributions of several intracellularly important cations, such as free calcium ions and protons. Typically, systems used for image processing are located centrally around the experimental setup. This configuration has drawbacks, mainly because the laborious extraction and processing of data that generally follow an experimental session limits the access to the system for other investigators. We describe here the principles of a distributed image processing system, based on IBM-compatible personal computers (PCs), that without extra hardware can cope with all the necessary image processing involved in imaging of intracellular cations. The potential of the PC as an image processor, however, reaches beyond this specific application and many image processing tasks can be carried out successfully on a standard PC. Thus, the centrally located dedicated image processor is used only for image acquisition in the experimental situation. This in turn optimizes the utilization of expensive resources and increases efficiency. The mouse-operated software is described in detail, so that interested investigators can extract useful parts for integration into their own applications and experimental environment.

We have studied the effect of maturation to small intestinal-like epithelial cells of the human colonic carcinoma cell line HT29 on the lateral mobility of different representative membrane components (lipid, proteins), as assessed with fluorescence recovery after photobleaching (FRAP). Maturation was induced in vitro in the HT29 cells by replacing glucose (Glu) with galactose (Gal) in the growth medium (DMEM) during a 21-day period. Scanning electron microscopy revealed an increased number of microvilli in the apical cell membrane, and enzyme analyses (alkaline phosphatase, aminopeptidase) in combination with aqueous countercurrent distribution, indicated that maturation was induced with DMEM-Gal. In comparison to control cells grown in DMEM-Glu medium, the more small intestinal-like cells grown in DMEM-Gal displayed no alteration of the lateral mobility of either cholera toxin (B subunit)-labelled ganglioside GM1 (diffusion coefficient, D [x 10(8)] = 0.8-0.9 cm2s-1; mobile fraction, R = 50-60%) or antibody-stained Class 2 histocompatibility (HLA-DR) antigen (D [x 10(9)] = 2 cm2s-1; R = 60-70%). However, antibody-labelled beta 2-microglobulin of HLA Class 1 antigen displayed increased mobility in HT29-Gal cells; D was x 1.4 and R x 1.8 larger in the HT29-Gal cells. By contrast, the mobility of a neoplastic antigen was reduced; D and R were x0.60 and x0.69 of the values seen in HT29-Glu cells. It is thus concluded that DMEM-Gal-induced differentiation in confluent HT29 cells is accompanied by specific rather than general effects on the lateral mobility of different membrane components.

The objective of this study was to determine the direction of membrane lipid flow in locomoting cells. The plasma membrane of human polymorphonuclear leukocytes was stained with a fluorescent lipid analog dihexadecanoyl indocarbocyanine. A line was photobleached on the cell surface perpendicular to the direction of cell motion. Low-light-level fluorescence microscopy and digital image-processing techniques were used to analyze a series of images taken at short intervals after photobleaching. The bleached line remained visible for about 5 seconds before being erased by diffusional recovery. Examination of fluorescence intensity profiles allowed a comparison to be made between the velocities of line and cell movement. Results indicate that the bleached line moves forward with the same velocity as the cell during locomotion, refuting the retrograde lipid flow model of locomotion. Instead, the plasma membrane lipid appears to move forward according to either the unit movement of membrane or the tank track model of locomotion.

The lateral diffusion of the secretory component (SC), acting as a receptor for dimeric IgA in the basolateral side of intestinal epithelial cells, was studied in the human colonic carcinoma cell line HT29. The HT29 cells were grown in Dulbecco's modified Eagle's medium in which galactose had been substituted for glucose to promote development of small intestine-like cells, with a distinct separation of the basolateral side from the apical surface. The SC was stained with rhodamine-labeled polyclonal anti-human SC rabbit antibodies (Ig) or Fab fragments, and the lateral mobility was assessed with the fluorescence recovery after photobleaching technique. The average lateral diffusion was consistent with a diffusion constant of 7.7 +/- 2.0 (mean value +/- SD; n = 29) and 7.1 +/- 2.3 (n = 30) x 10(-10) cm2s-1 for Ig-and Fab-labeled receptors, respectively, which is slower than lipid diffusion but is similar to that found for other membrane receptors. The corresponding values for the fraction of mobile receptors were 66 +/- 13% and 71 +/- 12%, respectively. Cells were labeled from the top of the culture plate, and cells adjacent to a mechanically made rift or a natural opening in the cell monolayer were labeled more strongly, confirming the microscope-based impression that the basolateral surface primarily harboured the SC receptor.

In a previous 16-month seasonal study on living (stained) benthic foraminifera from two fjords on the Swedish west coast, it was reported that foraminifera proliferated in response to phytodetritus input; the strongest response came from the opportunistic species Stainforthia fusiformis. In this study, our objective was to find out if that phytodetritus input resulted in a change in the carbon isotopic composition of the foraminiferal tests. We also wanted to examine if variations in salinity and temperature (due to seasonality or deep-water exchanges) were reflected in the δ18O values. From S. fusiformis that were obtained from the Havstens Fjord (20 m) and the Gullmar Fjord (119 m) during the 16-month study, we developed a time series of δ18O and δ13C. After the spring blooms in the Havstens and the Gullmar Fjord, decreases of about 0.2‰ to 0.3‰ in the foraminiferal δ13C values were noted; in the Gullmar Fjord after the autumn blooms, decreases of the same order were also noted. Comparing the Havstens and the Gullmar Fjord, we found a 1‰ difference in both δ13C and δ18O; we attribute this to hydrographic differences between the two fjords. Using calculated values of δ18O, together with the measured ones, we noticed that S. fusiformis in the Gullmar Fjord seems to calcify close to equilibrium with respect to the oxygen isotopes. During autumn, water temperatures were relatively high in the Havstens Fjord, and foraminiferal abundance in the fjord was also high after a phytodetritus input; but, the measured δ18O values do not reflect these higher temperatures. This apparently contradictory combination of results might be explained by a varying δ18O composition of the water during the year, which counterbalances the temperature effect.