The purpose of this study was to test whether pressure in tissue lateral to the upper airway, the lateral pharyngeal fat pad, differs from atmospheric and pharyngeal pressure and whether it changes with breathing. We studied five male pigs by inserting a transducer-tipped catheter into their fat pad space using ...

BACKGROUND: To investigate the theory of decreased myocardial oxygen consumption (MVo2) in dynamic cardiomyoplasty (DCM), previous studies have calculated indices of MVo2 in DCM. These previous studies, however, used left ventricular pressure in formulas that assumed the assumed the heart to be in its native state, with the reference pressure ...

A 100-microliters chamber has been developed to facilitate the use of optical techniques for the study of living cells under conditions of high hydrostatic pressure and other environmental manipulations. The chamber attaches to the mechanical stage of an inverted microscope and is capable of sustaining cells under physiologic conditions over ...

BACKGROUND: To assess the relation between occupational lead exposure and elevated blood pressure with consideration of a possible confounding effect by noise exposure. MATERIALS AND METHOD: Some 112 male and 110 female workers at two lead battery manufacturing factories were recruited for this 1992 study in Taiwan. Study participants received ...

A transportable hyperbaric chamber called the Gamow bag has been reported as an effective means of treating high-altitude illness. The pressure limit of the original bag is set at 2 psi because of the fragility of the fabric. However, improvement of the hardware to make the bag capable of withstanding ...

A 2-year-old male was found unresponsive approximately 40 min after oral exposure to butyrolactone (Figure 1), a solvent used to remove methacrylate glues. The patient was apneic, bradycardic, and flaccid. He was given atropine and orally intubated, and his heart rate increased and blood pressure remained normal. He remained unresponsive ...

A method for retrieving the atmospheric pressure corresponding to the tangent point of an infrared spectrum recorded in the solar occultation mode is described and applied to measurements made by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier-transform spectrometer. Tangent pressure values are inferred from measurements of isolated CO(2) lines with ...

A review of the literature on the relationship between blood pressure and stressor exposure revealed a discrepancy between the results of studies based on objective measures of stressor exposure and studies based on self-reports. Whereas in the studies based on objective measures, a clear predominance of positive associations between blood ...

We have studied pulmonary function before and 2 h after open sea dives to 10 and 50 m and 24 h after the dive to 10 m. Nine trainee divers participated in the dive to 10 m and 17 in the dive to 50 m. Mean time in water was ...

The Galileo probe performed the first in situ measurements of the atmosphere of Jupiter on 7 December 1995. The probe returned data until it reached a depth corresponding to an atmospheric pressure of approximately 24 bars. This report presents a brief overview of the origins and purpose of the mission. ...

The nephelometer experiment carried on the Galileo probe was designed to measure the jovian cloud structure and its microphysical characteristics from entry down to atmospheric pressure levels greater than 10 bars. Before this mission there was no direct evidence for the existence of the clouds below the uppermost cloud layer, ...

Respiratory sinus arrhythmia (RSA) has been used as a non-invasive estimate of vagal tone to determine whether the reduction in resting heart rate commonly seen when humans are exposed to increases in the ambient pressure is associated with changes in vagal autonomic control. Two sets of divers (n = 4) ...

OBJECTIVE: Our purpose was to determine whether there is a relationship between changes in atmospheric pressure and spontaneous onset of labor in term pregnancy. STUDY DESIGN: All women admitted to Medical Center of Central Massachusetts-Memorial Hospital with spontaneous onset of labor at term and who were delivered on the service ...

When human divers and experimental animals are exposed to increasing environmental pressure, they develop the high-pressure neurologic syndrome (HPNS) that has been recently demonstrated to include an increase in striatal dopamine (DA) release. This increase has been correlated with enhanced locomotor and motor activity (LMA). In the present study, we ...

Application of hydrostatic pressure of several atmospheres (atm), such as that applied in diving or hyperbaric treatment, has been previously shown to induce the release of membrane components into the extracellular medium. As the shape of red blood cells (RBC) is sensitive to membrane composition, this might imply a subsequent ...

Closed circuit rebreathers used by divers recirculate the respiratory gases through a scrubber to remove exhaled carbon dioxide. For systems used in deep diving applications, oxygen is mixed with a diluent gas to maintain a preset partial pressure of oxygen (PO2) that is within the physiologically acceptable limits for the ...

The composition of the Earth's early atmosphere is a subject of continuing debate. In particular, it has been suggested that elevated concentrations of atmospheric carbon dioxide would have been necessary to maintain normal surface temperatures in the face of lower solar luminosity in early Earth history. Fossil weathering profiles, known ...

The intestinal floras of seven deep-sea fish retrieved at depths of from 3,200 to 5,900 m were examined for population sizes and growth responses to pressure. Large populations of culturable bacteria, ranging from 1.1 x 10(sup6) to 3.6 x 10(sup8) cells per ml of contents, were detected when samples were ...

Psychotic-like episodes in divers exposed to high pressure have been attributed to either the high-pressure neurological syndrome, confinement in pressure chamber, the subject's personality, or the addition of nitrogen or hydrogen to the basic helium-oxygen breathing mixture used for deep diving. Alternatively, it is suggested that these disorders are in ...

We analyze the repercussions of air evacuation on the physiopathology of the critically burned patient based on the experience on 63 patients evacuated by air. Clinical repercussions are due to accelerations, vibrations, noise, and, primarily, to altitude. Accelerations are important during take-off and landing, and vibrations may be important in ...

Volcanic eruptions of gassy magmas on Earth, Venus, and Mars produce plumes with markedly different fluid dynamics regimes. In large part the differences are caused by the differing atmospheric pressures and ratios of volcanic vent pressure to atmospheric pressure. For each of these planets, numerical simulations of an eruption of ...

Barrier isolators that enclose aseptic filling equipment are being proposed as a means of: (1) assisting in achieving a 10(-6) sterility assurance level (SAL) in the filling area and (2) minimizing the clean environment required in the manufacturing area. The need for operator and maintenance access to the interior of ...

This study reports on the relationship between minute ventilation (VE) and environmental variables of temperature (T) and pressure (P) during open water diving. The author conducted a total of 38 dives involving either a light (20 dives) or a moderate (18 dives) level of physical activity. Within each of these ...

A new method has been developed for the determination of antimony, arsenic, bismuth, selenium, tellurium and tin by hydride generation-atomic absorption spectrometry in an electrically heated quartz tube furnace under sub-atmospheric pressure. The hydride generator, operating at a pressure lower than atmospheric, is used to generate and collect the hydrides ...

Myriophyllum heterophyllum Michx. is a rhizomatous submersed aquatic plant that produces a short, emergent floral spike. We hypothesized that lacunar pressures in emergent spikes should be at or near atmospheric pressure and that a mass flow of gases from submersed stems through the rhizome to emergent stems may occur as ...

To assess the contribution of hyperoxia to reduced pulmonary function after a deep saturation dive, a shallow saturation dive to a pressure of 0.25 MPa with the same profile of hyperoxic exposure as in a deep saturation dive to 3.7 MPa was conducted. The PO2 was 40 kPa, with periods ...

The National Aeronautics and Space Administration (NASA) Infrared Telescope Facility was used to investigate the collision of comet Shoemaker-Levy 9 with Jupiter from 12 July to 7 August 1994. Strong thermal infrared emission lasting several minutes was observed after the impacts of fragments C, G, and R. All impacts warmed ...

Electrocardiogram (ECG) analysis was performed in three human divers during a 71 atm (7,200 kPa) saturation dive (COMEX HYDRA 10 experiment). The inhaled gas mixture was slightly hyperoxic; its composition was basically helium and oxygen. Hydrogen was introduced during compression and its partial pressure reached 20 atm. ECG changes were ...

Previous attempts to find relationships between weather and parturition (childbirth) and its onset (the beginning of labor pains) have revealed, firstly, limited but statistically significant relationships between weather conditions much colder than the day before, with high winds and low pressure, and increased onsets; and secondly, increased numbers of childbirths ...

This work was performed to study the effect of pressure of various gas breathing mixtures on dopaminergic activity in the striatum by in vivo differential pulse voltammetry using carbon multifiber electrodes chronically implanted in 23 freely moving rats. Compression (0.5 bar/min) in a helium-oxygen mixture induced an increase in striatal ...

Expirograms for CO2 and O2 obtained immediately after 75-s breath holds (BHs) in thermoneutral conditions were studied in 10 subjects. BHs were performed at normal atmospheric pressure in dry condition (dry surface BH), at normal atmospheric pressure submerged (wet surface BH), and during a transient increase of ambient pressure to ...

The microsphere technique was used to determine whether blood flow to the central nervous system and various organs is impaired in rats with spinal cord injury induced by decompression sickness. For this purpose cannulas were placed in the left ventricle of the rats for the injection of microspheres and in ...

An experiment was conducted to determine whether differences in the electrocardiograms (EKGs) of broilers reared at simulated high altitude from the day of hatch can be used to predict which birds are developing ascites. In three replicate experiments, conducted with 100 broilers per replicate, birds were reared at a simulated ...

A simple steady-state photochemical model is developed in order to determine typical molecular oxygen concentrations for a comprehensive range of primitive abiotic atmospheres. Carbon dioxide is assumed to be the dominant constituent in these atmospheres since CO2 photodissociation may potentially result in the enhancement of the O2 partial pressure. The ...

Four different brands of bone cement (Palacos R, Simplex P, Sulfix, CMW 1) were tested for exothermic changes during polymerization at atmospheric pressure and under partial vacuum of 0.2 bar. Palacos R was also mixed at four pressure levels (1.0, 0.2, 0.12, and 0.05 bar). The peak temperature in the ...

Because hydrostatic pressure can antagonize the behavioral effects of anesthetics in many organisms, we examined whether ethanol-induced immobility of the nematode Caenorhabditis elegans was antagonized by 100 ATA pressure. Nematode mobility was examined at pressures ranging from 1 ATA to 132 ATA, with and without increasing concentrations of ethanol (0-1 ...

The cellular mechanisms underlying the effects of high pressure, GABAergic presynaptic inhibition, and low [Ca2+]0 on glutamatergic excitatory synaptic transmission were studied in the opener muscle of the lobster walking leg. Excitatory postsynaptic currents (EPSCs) were recorded with or without prior stimulation of the inhibitor using a loose macropatch clamp ...

Divers have worked at 500 m depth in the sea and have reached 700 m in simulated chamber dives. A prerequisite for this has been extensive physiological studies of the body's reactions to pressure and pressure changes. This paper reviews such physiological and pathophysiological studies with emphasis on recent developments.

Atmospheric leakage between a CELSS and its surround is driven by the differential pressure between the two. In an earth-based CELSS, both negative and positive differential pressures of atmosphere are created as the resultant of three influences: thermal expansion/contraction, transition of water between liquid and vapor phases, and external barometric ...

To investigate the possibility of lung injury after long-term saturation dives where oxygen partial pressure was kept between 42 and 50 kPa, we measured lung volumes, diffusing capacity (DLCO/VA), and ethane production in the alveolar expirate on six divers who participated in a 1.1-MPa saturation dive (9 days of total ...

The neurophysiological effects of the novel anticonvulsant lamotrigine on the high pressure neurological syndrome, HPNS, were investigated in the rat and nonhuman primate Papio anubis. Rats were exposed to pressure at a rate of 3 ATA per min in a helium/oxygen environment. They were pretreated with either lamotrigine isethionate 15, ...

Six commercial divers were investigated for neurological and psychosensorimotor responses during an open sea dive to 500 m with a hydrogen-helium-oxygen mixture containing 49% hydrogen. Results showed only moderate neurological symptoms of high-pressure nervous syndrome, whereas the narcotic effect of hydrogen was detectable, as investigated by psychosensorimotor tests. Nevertheless, the ...

Accurate determination of the calibration constant is essential for the reliable determination of indoor radon air concentrations using alpha-track detectors. One possible source of error in the application of this method of radon assay is an effect of air density on the calibration factor. Such an effect, if present, could ...

When human divers or experimental animals are exposed to high pressure, they develop brain and biobehavioural disorders. Since it has been demonstrated that pressure exposure increased striatal DA release, the present experiments were intended to investigate whether it resulted from a release in de novo synthesized DA or from a ...

Suspended cells of the human neuroblastoma line SK-N-SH were exposed to elevated pressures of non-narcotic helium (He) and the narcotic gases nitrogen (N2), and argon (Ar) and stimulated with carbachol. He, 18 and 36 atmospheres absolute (ATA), equivalent to 544 and 1120 feet of seawater, potentiated the increase in [Ca2+]i ...

Nine cats with the cochlear aqueduct surgically blocked were anaesthetised, put in a pressure chamber, and stepwise exposed to hypobaric pressure, each of the two steps lasting 5 min. The chamber pressure was reduced to -5 and -7 kPa. Concluding the experiment the cats were observed for 5 min after ...

Deep saturation diving has been shown to have prolonged effects on pulmonary function. We wanted to assess the relative contribution of various factors that could contribute to these effects. Pulmonary function was, therefore, measured before and after 17 different saturation diving operations to depths of 5-450 m of sea water, ...

Very little is known about the effects of pressure within the vascular system on EC phenotype. To study this, bovine aortic EC were seeded on rat type I collagen plates (2,000/cm2) and allowed to attach for 24 hours. The cells were exposed to either atmospheric, 40, 80, or 120 mm ...

At high cabin pressure [e.g. 1013 hPa (14.7 psi) 21% O2] there are serious issues relative to specification of suit pressure and the need for prebreathing. A high pressure suit will be costly but use of the existing, flexible suit requires up to 6 h of prebreathing. Or one could ...

Impairments of psychomotor, perceptual, and cognitive abilities were determined in nine male subjects exposed to inhaled SF6 partial pressures of 0, 52, 104, and 156 kPa and to inhaled N2 partial pressures of 103, 575, 825, and 1,075 kPa. Also data from a previous study with inhaled N2O partial pressures ...