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Biomedical subjects

W Goetz

Publications and source records attributed to W Goetz.

13 recordsLinked to original sources
PubMed2004

Pancam multispectral imaging results from the Opportunity Rover at Meridiani Planum.

Panoramic Camera (Pancam) images from Meridiani Planum reveal a low-albedo, generally flat, and relatively rock-free surface. Within and around impact craters and fractures, laminated outcrop rocks with higher albedo are observed. Fine-grained materials include dark sand, bright ferric iron-rich dust, angular rock clasts, and millimeter-size spheroidal granules that are eroding out of the laminated rocks. Spectra of sand, clasts, and one dark plains rock are consistent with mafic silicates such as pyroxene and olivine. Spectra of both the spherules and the laminated outcrop materials indicate the presence of crystalline ferric oxides or oxyhydroxides. Atmospheric observations show a steady decline in dust opacity during the mission. Astronomical observations captured solar transits by Phobos and Deimos and time-lapse observations of sunsets.

Atmosphere↗
PubMed2004

Magnetic properties experiments on the Mars exploration Rover Spirit at Gusev Crater.

The magnetic properties experiments are designed to help identify the magnetic minerals in the dust and rocks on Mars-and to determine whether liquid water was involved in the formation and alteration of these magnetic minerals. Almost all of the dust particles suspended in the martian atmosphere must contain ferrimagnetic minerals (such as maghemite or magnetite) in an amount of approximately 2% by weight. The most magnetic fraction of the dust appears darker than the average dust. Magnetite was detected in the first two rocks ground by Spirit.

Atmosphere↗
PubMed2004

Pancam multispectral imaging results from the Spirit Rover at Gusev Crater.

Panoramic Camera images at Gusev crater reveal a rock-strewn surface interspersed with high- to moderate-albedo fine-grained deposits occurring in part as drifts or in small circular swales or hollows. Optically thick coatings of fine-grained ferric iron-rich dust dominate most bright soil and rock surfaces. Spectra of some darker rock surfaces and rock regions exposed by brushing or grinding show near-infrared spectral signatures consistent with the presence of mafic silicates such as pyroxene or olivine. Atmospheric observations show a steady decline in dust opacity during the mission, and astronomical observations captured solar transits by the martian moons, Phobos and Deimos, as well as a view of Earth from the martian surface.

Atmosphere↗
PubMed2002

Aortic and pulmonary root: are their dynamics similar?

OBJECTIVES: The long-term behavior of the pulmonary autograft in the aortic position (Ross procedure) remains uncertain. Using three-dimensional (3D) sonomicrometry (200 Hz) we compared the dynamics of the aortic and pulmonary roots. METHODS: Twenty-four crystals were implanted in each aortic (eight sheep) and pulmonary roots (six sheep) at: base (3 x 2), commissures (3 x 2), sinotubular junction (3 x 2), ascending aorta (3) and pulmonary trunk (3). Under stable hemodynamic conditions, geometric changes were time-related to left ventricular pressure (LV) and aortic pressure. RESULTS: The expansion of the aortic root is twice that of the pulmonary root. During the cardiac cycle, the aortic root volume increased by 37.7 +/- 2.7% (mean +/- SEM) versus 20.9 +/- 1.0% for the pulmonary root. Both were cone-shaped at end diastole. Because expansion at commissures was twice that of the base, both roots became more cylindrical during ejection. Although both roots started to expand prior to ejection and reached maximal expansion during the first third of ejection, the commissural and sinotubular junction dynamics were different in each root. While in the aortic root, expansion at commissural and sinotubular junction levels was significantly different (63.7 +/- 3.6% versus 37.0 +/- 2.1%), in the pulmonary root, they were similar (29.0 +/- 1.3% versus 27.7 +/- 1.4%). Expansion of the three sinuses was also different (P<0.001). In the aortic root: the right expanded more than the left and more than the non-coronary sinus. In the pulmonary root: the right sinus expanded more than the anterior more than the left. CONCLUSIONS: Dynamic differences might explain the global pulmonary root dilatation when subjected to systemic pressure, particularly at the level of the sinotubular junction which might result in the autograft failure. Differences in the asymmetrical expansion of the aortic and pulmonary roots should be considered for the implantation of the pulmonary autograft in the most physiological position.

Analysis of Variance↗
PubMed2002

A four-dimensional study of the aortic root dynamics.

OBJECTIVE: Although aortic root expansion has been well studied, its deformation and physiologic relevance remain controversial. Three-dimensional (3-D) sonomicrometry (200Hz) has made time-related 4-D study possible. METHODS: Fifteen sonomicrometric crystals were implanted into the aortic root of eight sheep at each base (three), commissures (three), sinuses of Valsalva (three), sinotubular junction (three), and ascending aorta (three). In this acute, open-chest model, the aortic root geometric deformations were time related to left ventricular and aortic pressures. RESULTS: During the cardiac cycle, aortic root volume increased by mean+/-1 standard error of the mean (SEM) 33.7+/-2.7%, with 36.7+/-3.3% occurring prior to ejection. Expansion started during isovolumic contraction at the base and commissures followed (after a delay) by the sinotubular junction. At the same time, ascending aorta area decreased (-2.6+/-0.4%). During the first third of ejection, the aortic root reached maximal expansion followed by a slow, then late rapid decrease in volume until mid-diastole. During end-diastole, the aortic root volume re-expanded by 11.3+/-2.4%, but with different dynamics at each area level. Although the base and commissural areas re-expanded, the sinotubular junction and ascending aorta areas kept decreasing. At end-diastole, the aortic root had a truncated cone shape (base area>commissures area by 51.6+/-2.0%). During systole, the root became more cylindrical (base area>commissures area by 39.2+/-2.5%) because most of the significant changes occurred at commissural level (63.7+/-3.6%). CONCLUSION: Aortic root expansion follows a precise chronology during systole and becomes more cylindrical - probably to maximize ejection. These findings might stimulate a more physiologic approach to aortic valve and aortic root surgical procedures.

Animals↗
PubMed1997

Magnetic properties experiments on the Mars Pathfinder lander: preliminary results.

Many of the particles currently suspended in the martian atmosphere are magnetic, with an average saturation magnetization of about 4 A. m2/kg (amperes times square meters per kilogram). The particles appear to consist of claylike aggregates stained or cemented with ferric oxide (Fe2O3); at least some of the stain and cement is probably maghemite (gamma-Fe2O3). The presence of the gamma phase would imply that Fe2+ ions leached from the bedrock, passing through a state as free Fe2+ ions dissolved in liquid water. These particles could be a freeze-dried precipitate from ground water poured out on the surface. An alternative is that the magnetic particles are titanomagnetite occurring in palagonite and inherited directly from a basaltic precursor.

Atmosphere↗
PubMed1996

[Contribution of Aleksander Sapieha (1773-1812) into European galvanization therapy].

For the development of the therapy using electricity as agent two tracks can be identified. On the one side, the indication for applying this therapy was handled more careful, simultaneously the technical equipment was improved. The Polish noble man Alexander Sapieha (1773-1812), the leading natural scientist of the Granddukedom of Warsaw, cooperated with excellent European scientists in order to improve the galvanic battery technologically. Among these scientists were Alexander Volta (1745-1827), the inventor of the battery, and Johann Bartholomaeus Trommsdorff (1770-1837), who is considered as one of the founders of scientific pharmacy in Europe. A. Sapieha supported the publication of galvanic experiences, e.g. in the case of Alexander of Humboldt (1769-1859) by publishing his paper about electric fishes. Sapiehas connections with the scientific centers in Turin and Bologna, Erfurt, Warszaw and Paris accelerated the exchange of information about galvanism. Later the resulting mini-batteries were employed in diathermie, in defibrillators and pacemakers. Details about these connections are presented in the lecture resp. full paper.

Electric Stimulation Therapy↗
PubMed1994

Light and electron microscopical immunohistochemical localization of the small proteoglycan core proteins decorin and biglycan in human knee joint cartilage.

The distribution of decorin and biglycan was investigated at the light and electron microscopical level in adult human articular cartilage. In general, the amount of decorin and biglycan was found to decrease with the depth of the layer of the cartilage. Decorin was found in the interterritorial matrix where most of the collagen is located. This fits in well with the assumption that decorin may modulate collagen metabolism. Biglycan was found next to the chondrocytes in the pericellular matrix and is assumed to be responsible for cellular activities. At the ultrastructural level, decorin was localized in the interterritorial matrix and in vesicles in chondrocytes. Biglycan was found, usually though not exclusively in the pericellular matrix. Both small proteoglycans were detected close to and on the collagen fibres and also associated with the more globular structures of the matrix between the fibrils. A double-staining approach revealed that the two molecules could be located along the same collagen fibril. However, staining for biglycan and decorin was not observed simultaneously within the same region of the fibre.

Adult↗
PubMed1987

Multicenter hypothermia survey.

A multicenter survey evaluated the clinical presentation, treatment, and outcome of accidental hypothermia. Data were collected from 13 emergency departments, with 401 of the 428 cases presenting during a two-year study period. Core temperatures ranged from 35 C to 15.6 C (mean, 30.57 C +/- 3.53) with 272 cases (63.6%) less than or equal to 32.2 C. There were no significant differences by age in presenting temperature, rewarming strategies, or mortality. The first hour rewarming rate was significantly (P less than .05) faster in the population less than or equal to 59 years (1.08 +/- 1.39 C/hr) than in those greater than or equal to 60 years (0.75 +/- 1.16 C/hr). Male core temperatures averaged 30.27 +/- 3.44 C versus female temperatures of 31.1 +/- 3.61 C. There were no clinically significant differences in male (N = 296) versus female (N = 132) profiles. High ethanol levels (315 to 800 mg%) did not affect outcome. Nine of 27 (33%) patients who received CPR initiated in the field survived, versus six of 14 (43%) with CPR begun in the ED. The profile of the CPR versus non-CPR population differed significantly (P less than .05) in location (outdoors), initial temperature (24.8 +/- 3.77 C vs 30.94 +/- 3.12 C), third-hour rewarming rate (2.28 +/- 1.53 C vs 1.17 +/- 1.18 C/hr), and numerous laboratory parameters. Tracheal intubation was performed without incident in 117 cases, of which 97 were less than or equal to 32.2 C. There were 73 fatalities (17.1%). Of these, 84.9% (N = 62) were less than or equal to 32.2 C. Predisposing conditions in this group included "serious" illness (30), systemic infection (28), trauma (15), immersion (ten), frostbite (seven), and overdose (two). The initial pulse, hemoglobin, and first-hour rewarming rate was lower in the deceased population, while the potassium, urea nitrogen, creatinine, and phosphorus were elevated. Excluding treatment combinations, outcome with exclusive use of a single rewarming strategy was passive external rewarming, 14 deaths below 32.2 C, 13 above; active external rewarming, six deaths below 32.2 C, two above; active core rewarming, 38 deaths below 32.2 C, none above. Refinements of the American Heart Association's CPR standards in hypothermia and a Hypothermia Survival Index are proposed.

Age Factors↗
PubMed1986

Hemodynamic oxygen transport and 2,3-diphosphoglycerate changes after transfusion of patients in acute respiratory failure.

The goals of management of patients with respiratory failure include improving arterial oxygenation with PEEP and red cell transfusion to maintain oxygen carrying capacity, both of which contribute to improving tissue oxygen delivery. However, standard CPD-stored blood is rapidly depleted of 2,3 diphosphoglycerate (2,3 DPG) and ATP, with resultant inadequacy of the red cell oxygen transport function. In 15 patients requiring mechanical ventilation with PEEP whose initial Hct less than or equal to 35%, we studied the effect of transfusion of 7 ml/kg of CPD-stored packed red blood cells on hemodynamic and oxygen delivery variables, pulmonary venous admixture (QA/QT), and erythrocytic P50, 2,3 DPG and ATP concentrations. Hemodynamics were not significantly altered by transfusion. 2,3 DPG decreased significantly from 14.5 +/- 1.1 to 13.1 +/- 1.5 mcmol/g Hb (mean +/- SD, p less than 0.05). There was no significant change in P50 or ATP. QA/QT rose significantly, from 20.1 +/- 7.8 to 28.9 +/- 12.3% (mean +/- SD, p less than 0.02). In our patients, an increase in arterial oxygen content obtained by transfusion was not followed by any associated decrease in cardiac work, as implied by solution of equations for oxygen delivery and oxygen consumption. The rise in QA/QT is undesirable in patients requiring PEEP, since it complicates management of their mechanical ventilatory support.

2,3-Diphosphoglycerate↗