Biomedical subjects

D Grill

Publications and source records attributed to D Grill.

At least 19 recordsLinked to original sources

PubMed2006

Cerebral venous sinus thrombosis: Incidence of venous thrombosis recurrence and survival.

OBJECTIVE: To determine whether treatments guidelines for lower extremity venous thrombosis (DVT) could be applied to patients with cerebral venous sinus thrombosis (CVST), the rates of recurrent venous thrombosis and survival for these two diseases were compared. METHODS: The authors studied all patients diagnosed with CVST at the Mayo Clinic between 1978 and 2001. Survival and recurrent venous thrombosis rates (cerebral or noncerebral) were compared with those from patients with DVT. Survival rates were also compared with white US residents. RESULTS: One hundred fifty-four patients (age 40 +/- 19 years) were included (58% women). Warfarin, prescribed in 50% of patients, was continued for an average of 9 months. During a mean of follow up of 36 +/- 47 months (464 patient-years), 20 patients experienced 23 recurrent venous thrombi for an event rate of 5.0/100 patient-years. This recurrence rate was similar to patients with lower extremity DVT (3.8/100 patient-years). Mortality rates were lower for CVST (2.8/100 patient-years) compared with DVT (6.2/100 patient-years; p = 0.001) patients but higher than expected for white US residents (p = 0.001). Increasing age and active malignancy were the only predictors of poor survival. Neither recurrent thrombosis nor survival was influenced by warfarin therapy. CONCLUSIONS: The likelihood of recurrent venous thrombosis is similar after cerebral venous sinus thrombosis (CVST) and lower extremity deep venous thrombosis (DVT). Compared with DVT, survival rates are higher following CVST but are adversely influenced by malignancy and older age.

Adolescent↗

PubMed2006

Sugar-, acid- and phenol contents in apple cultivars from organic and integrated fruit cultivation.

OBJECTIVE: This study was carried out to obtain data about the sugar-, acid- and phenol content of apple cultivars from organic and integrated fruit cultivation, with reference to their role in human health and especially for diet recommendations. SETTING: Styria (Austria) and Slovenia. INTERVENTIONS: HPLC, Spectral Photometry, organoleptic and olfactory tests. RESULTS: The total sugar content of most cultivars from integrated cultivation ranged between 115 and 160 g/kg. Some cultivars from organic growing reached higher values. The acid content of both cultivar types was similar. The phenol content in organically grown cultivars was much higher than that of the ones from integrated cultivation. CONCLUSION: Knowledge of the sugar content is very important for diabetic patients, owing to the assumption of general diet recommendations that 100 g fruit contain 12 g carbohydrates. This applies to most well-known cultivars like Golden Delicious or Gala, but not to most of the regional cultivars. For diabetics, it is necessary to know the carbohydrate content of food precisely, in order to adapt the amount of insulin to the ingestion. So, it is helpful to know the sugar content of each regional cultivar. Moreover, very high levels of phenolic compound in organically grown cultivars, and with it its importance for human health leads to the recommendation to eat regional fruits from organic fruit growing instead of those grown under integrated cultivation.

Acids↗

PubMed2005

Tree age dependence and within-canopy variation of leaf gas exchange and antioxidative defence in Fagus sylvatica under experimental free-air ozone exposure.

We characterized leaf gas exchange and antioxidative defence of two-year-old seedlings and 60-year-old trees of Fagus sylvatica exposed to ambient (1 x O3) or two-fold ambient (2 x O3) O3 concentrations (maximum of 150 ppb) in a free-air canopy exposure system throughout the growing season. Decline in photosynthesis from sun-exposed to shaded conditions was more pronounced in adult than juvenile trees. Seedling leaves and leaves in the sun-exposed canopy had higher stomatal conductance and higher internal CO2 concentrations relative to leaves of adult trees and leaves in shaded conditions. There was a weak overall depression of photosynthesis in the 2 x O3 variants across age classes and canopy positions. Pigment and tocopherol concentrations of leaves were significantly affected by canopy position and tree age, whereas differences between 1 x O3 and 2 x O3 regimes were not observed. Glutathione concentrations were significantly increased under 2 x O3 across both age classes and canopy levels. Seedlings differed from adult trees in relevant physiological and biochemical traits in ozone response. The water-soluble antioxidative systems responded most sensitively to 2 x O3 without regard of tree age or canopy position.

Acclimatization↗

PubMed2002

Tree- and needle-age-dependent variations in antioxidants and photoprotective pigments in Norway spruce needles at the alpine timberline.

To cope with environmental stress, plants are equipped with antioxidative (e.g., ascorbate, glutathione and alpha-tocopherol) and photoprotective (e.g., xanthophyll cycle pigments) defense systems. We investigated the defense capacities of three tree age classes (mature, sapling and seedling) of Norway spruce (Picea abies (L.) Karst.) at a field site near the timberline. Biochemical data were expressed on both a needle dry mass and a surface area basis. Compared with current-year needles, previous-year needles contained higher mass- and area-based concentrations of chlorophylls and alpha-tocopherol, and a larger xanthophyll cycle pool that was in a more epoxidized state. Total glutathione concentration was lower, the glutathione pool was more reduced and the ascorbate pool was more oxidized in previous-year needles than in current-year needles. Needle concentrations of glutathione and alpha-tocopherol increased and chlorophyll concentration decreased with increasing tree age when expressed on a surface area basis. On a dry mass basis, these trends were reversed or nonexistent. The ascorbate pool was more reduced and the glutathione pool was more oxidized in needles of mature trees than in needles of saplings and seedlings. The proportion of protective xanthophyll cycle pigments decreased and the de-epoxidation state increased with increasing tree age. We conclude that tree age and the basis of expression of antioxidant concentration--surface area or dry mass--are important in scaling from seedlings to large trees.

Antioxidants↗

PubMed2001

Multivariate patterns of biochemical responses of Pinus ponderosa trees at field plots in the San Bernardino Mountains, southern California.

Most environmental stress conditions promote the production of potentially toxic active oxygen species in plant cells. Plants respond with changes in their antioxidant and photoprotective systems. Antioxidants and pigments have been widely used to measure these responses. Because trees are exposed to multiple man-made and natural stresses, their responses are not reflected by changes in single stress markers, but by complex biochemical changes. To evaluate such response patterns, explorative multivariate statistics have been used. In the present study, 12 biochemical variables (chloroplast pigments, state of the xanthophyll cycle, alpha-tocopherol, ascorbate and dehydroascorbate, glutathione and oxidized glutathione) were measured in previous-year needles of field-grown Pinus ponderosa Dougl. ex Laws. The trees were sampled in two consecutive years in the San Bernardino Mountains in southern California, where a pollution gradient is overlaid by gradients in natural stresses (drought, altitude). To explore irradiance effects, needle samples were taken directly in the field (sun exposed) and from detached, dark-adapted branches. A principal component analysis on this data set (n = 80) resulted in four components (Components 1-4) that explained 67% of the variance in the original data. Component 1 was positively loaded by concentrations of alpha-tocopherol, total ascorbate and xanthophyll cycle pools, as well as by the proportion of de-epoxides in the xanthophyll cycle. It was negatively loaded by the proportion of dehydroascorbate in the ascorbate pool. Component 2 was negatively loaded by chlorophyll concentrations, and positively loaded by the ratios of lutein and beta-carotene to chlorophyll and by the de-epoxidation state of the xanthophyll cycle. Component 3 was negatively loaded by GSH concentrations and positively loaded by the proportions of GSSG and tocopherol concentrations. Component 4 was positively loaded by neoxanthin and negatively loaded by beta-carotene. The four components could be assigned to the concerted action of the biochemical protection system: high scores on Component 1 represent highly activated antioxidative defense, changes in pigment composition are represented in Components 2 and 4, and the glutathione system, which is important for antioxidant regeneration, is represented in Component 2. Although Component 1 scores were generally higher (indicating activation of antioxidant defense) in light-adapted needles relative to dark-adapted needles, they were also site dependent with increased scores at sites with less pollution, but higher natural stress impacts. High scores of Components 2 and 3 at the highest elevation site, which was only moderately polluted, indicated an increase in photoprotection by pigments and activation of the glutathione system. Significant differences between light- and dark-adapted needles in Components 2 and 3 were only found at the site with the highest pollution. Use of accumulated variables (components) instead of single biochemical variables enabled recognition of response patterns at particular sites and a better comparison with results of other studies is expected. Typical response patterns could be assigned to particular environmental stress combinations, providing a means of assessing potential biological risks within individual forest stands.

Air Pollution↗

PubMed2000

Image quality assessment in contemporary interventional cardiology laboratories: spatial and low-contrast video resolution.

Two measures of fluoroscopic image quality-high-contrast video spatial resolution and low-contrast video resolution-were assessed in 64 interventional cardiology catheterization laboratories. The results of high-contrast spatial resolution testing indicate variable levels of performance with median values of 1.5, 2.0, and 2.5 line pairs/mm at the three levels of magnification. The results of the low-contrast video resolution testing indicate clinically relevant limitations in performance. This was particularly true when testing was performed in a dynamic mode under simulated large patient conditions. Under these conditions, 50% of systems failed to detect a wire of diameter 0.017". In addition, limited system dynamic range was identified in a substantial fraction of laboratories and may contribute to these important variations in performance. Taken together, these findings serve to characterize overall system performance in the current era of interventional cardiology and reaffirm the continued need for image quality assessment programs.

Cardiac Catheterization↗

PubMed1999

Clopidogrel versus ticlopidine after intracoronary stent placement.

OBJECTIVES: The study compared the safety and efficacy of ticlopidine with clopidogrel in patients receiving coronary stents. BACKGROUND: Stent thrombosis is reduced when ticlopidine is administered with aspirin. Clopidogrel is similar to ticlopidine in chemical structure and function but has fewer side effects; few data are available about its use in stent patients. METHODS: We compared 30-day event rates in 500 consecutive coronary stent patients treated with aspirin and clopidogrel (300 mg loading dose immediately prior to stent placement, and 75 mg/day for 14 days) to 827 consecutive stent patients treated with aspirin and ticlopidine (500 mg loading dose and 250 mg twice daily for 14 days). RESULTS: Patients treated with clopidogrel had more adverse clinical characteristics including older age, more severe angina, and more frequent infarction within the prior 24 h. Nonetheless, mortality was 0.4% in clopidogrel patients versus 1.1% in ticlopidine patients; nonfatal myocardial infarction occurred in 0% versus 0.5%, stent thrombosis in 0.2% versus 0.7%, bypass surgery or repeat angioplasty in 0.4% versus 0.5%, and any event occurred in 0.8% versus 1.6% of patients, respectively (p = NS). Based on the observed 30-day event rate of 1.6% with ticlopidine, the statistical power of the study was 43% to detect an even rate of 0.5% with clopidogrel, and 75% to detect an event rate with of 4% with clopidogrel, with a p value of 0.05. CONCLUSIONS: These data indicate that clopidogrel can be safely substituted for ticlopidine in patients receiving coronary stents.

Aged↗

PubMed1999

Antioxidants and protective pigments of Pinus ponderosa needles at gradients of natural stresses and ozone in the San Bernardino Mountains in California.

At the San Bernardino Mountains, California, a well documented gradient of ozone pollution overlays a natural stress gradient from mesic to dry and from lower elevation to higher elevation sites. In contrast to gradient studies in European regions, the highest ambient ozone levels are observed at low elevation and more mesic locations. In the present study, antioxidative and photoprotective systems in Pinus ponderosa needles were investigated at three plots--DW (1725 m, high ozone impact, mesic site), SW (1200 m, clean air, xeric site) and CO (above 2000 m, clean air and xeric site). Needles from the CO site contained significantly more total GSH (500 vs 300 nmol g(-1) dw in c needles), less alpha-carotene (6-10 vs 14-19 microg mg(-1) total chlorophyll) and chlorophyll (1.7-2 vs 2.5-2.6 mg g(-1) dw in c + 1 needles) than those at the DW site. Furthermore, their xanthophyll cycle pool was in a more de-epoxidized state at midday (up to 60% in c needles), and the carotenoid/chlorophylls ratios were generally higher. These patterns correspond to those observed at higher elevation plots in the Alps. On the other hand, needles from the high ozone site (DW) had a higher proportion of GSSG, indicating the onset of biochemical injury to needles. Needles from the SW site had intermediate proportions of GSSG. The results show the potential of environmental stressors to induce antioxidative and photoprotective responses in the absence of elevated ozone concentrations, but support the oxidative effects of ozone injury to ponderosa pine.

Air Pollutants↗

PubMed1999

Effects of an oxidizing agent (hydrogen peroxide) on the glutathione system in epidermal cells of Allium cepa L. investigated by histochemical staining.

The glutathione system in epidermal cells of Allium cepa L. was measured by a quantitative image analysis method, using histochemical staining by monochlorobimane. Blockage of thiol groups with N-ethylmaleimide decreased fluorescence to a small rest fluorescence of maximum 5%. Pre-treatment with dithiothreitol increased fluorescence yield in all cells compared to the monochlorobimane treatment alone. These results correspond to the blockage or the reduction of the total pool of glutathione in the cells. After treatment with N-ethylmaleimide and subsequent incubation with dithiothreitol followed by labelling with bimane a low fluorescence yield was observed which correspond to the proportion of GSSG. Specimens that were incubated in H2O2 prior to the treatments described above exhibited a decrease in total glutathione and in reduced glutathione and an increase in the proportion of GSSG compared to the control.

Allium↗

PubMed1998

Variability of radiation output dynamic range in modern cardiac catheterization imaging systems.

Automatic exposure control (AEC) is one of the most important characteristics for optimizing cardiac catheterization imaging; this allows the X-ray system to provide sufficient radiation output under a variety of clinical conditions so that a satisfactory image is obtained. AEC was assessed in 97 cardiac catheterization laboratories using a standard set of phantoms. Three different copper attenuators were used to simulate three patient sizes. As magnification increased, many systems had limited dynamic range and were unable to increase radiation output. With increasing atttenuator thickness, the problem worsened. With the thickest attenuator and largest magnification (4.5"-5.0" FOV), 60% of systems could not achieve the typical 70% increase in exposure while 20% were unable to increase radiation output at all.

Body Burden↗

PubMed1997

Increased stress parameter synthesis in the yeast Saccharomyces cerevisiae after treatment with 4-hydroxy-2-nonenal.

The metabolism of glutathione (GSH), a marker of oxidative stress and trehalose, a rather general physiological stress marker, was examined in exponentially growing Saccharomyces cerevisiae cells after treatment with 4-hydroxynonenal (HNE). GSH was entirely depleted within a 2 h incubation with 250 microM HNE. After removal of the aldehyde it was replenished by de novo synthesis leading to an overshooting GSH level, which later decreased to the basal level. In addition, trehalose was elevated 4-fold in HNE-treated yeast cells compared to control cells. We conclude that increased GSH levels upon HNE treatment are a general phenomenon of eukaryotic cells to ensure protection and survival during further harsh conditions. Furthermore, we have discovered a new indication for the stress marker trehalose in S. cerevisiae.

Aldehydes↗

PubMed1995

Time to reperfusion and other procedural characteristics of emergency coronary artery bypass surgery after unsuccessful coronary angioplasty.

A databank search was performed and 148 consecutive patients (mean age 59.5 +/- 10.4 years) were identified who underwent emergency coronary artery bypass surgery at the Mayo Clinic between November 20, 1979, and February 12, 1992, immediately after unsuccessful coronary angioplasty. At the end of the angioplasty procedure, there was no anterograde coronary blood flow in the treated artery in 54%, ongoing chest pain in 78%, and hemodynamic compromise requiring intravenous vasopressor therapy in 25% of patients; 127 patients (86%) had at least 1 of these adverse characteristics. After leaving the catheterization laboratory, the median time to arrival in the operating room was 12 minutes. Median time from arrival in the operating room to initiation of cardiopulmonary bypass was 86 minutes, to administration of cardioplegia was 98 minutes, and to removal of the aortic cross-clamp was 135 minutes. In-hospital mortality was 11%, and 18% developed nonfatal Q-wave myocardial infarction. Thus, significant time is required to achieve surgical reperfusion after unsuccessful coronary angioplasty.

Aged↗

PubMed1993

A perfusion chamber with temperature regulation.

When investigating microscopic preparations perfusion chambers allow exchange and regulation of different solutions and ensure their constant flow in the sample chamber. Temperature deviations, however, may be problematic. We describe a new chamber that contains an additional circulation system which regulates the inside temperature using an external thermostat. An integrated thermometer probe records the sample temperature, which appears on a monitor. The glass chamber, measuring 75 x 35 x 3 mm, provides good optical quality and is compatible with every type of microscope.

Microscopy↗

PubMed1990

[Air pollution and sudden infant death in Graz 1982 to 1987].

We correlated the incidence of the sudden infant death syndrome (SIDS) and the degree of air pollution in each district of Graz over a time period of five years. The degree of air pollution was derived from a mapping of epiphytical lichen vegetation by Grill et al. (1988). We found an increased incidence of SIDS in districts with poor air quality. Although this result is not statistically significant a possible increase in SIDS risk because of air pollution cannot be excluded. Some pathophysiological explanations are discussed.

Air Pollution↗

PubMed1990

Physiology of young Norway spruce.

In the Hohenheim experiment young spruce (Picea abies L. Karst.) were exposed to low levels of SO(2) and/or O(3) and acid precipitation. At the end of a five-year experimental period (1983-88) the following physiological parameters were examined: water soluble thiols, ascorbic acid, glutathionereductase activity and pigment content. Exposure to SO(2), leads to an increase in thiol content, to a slight decrease of ascorbic acid and to a pronounced decrease of pigments. O(3) exposure increases the content of ascorbic acid and decreases the thiols and the glutathione-reductase activity with no change in the pigment content. The combined exposure to SO(2), and O(3) results in the most distinct deviations compared to the control chamber response. These needles show the highest increase of ascorbic acid and thiols, the dry weight is decreased as is the glutathione-reductase activity and the pigment content is reduced. Consequences of these physiological alterations for the plant's health are discussed.

Journal Article↗

PubMed1987

Detection of sulphite in plants.

Artificially SO(2)-fumigated plant material was investigated for its sulphite content. Experiments with moderate concentrations of SO(2) (0.15-0.45 mg m(-3) lasting for 3 weeks, showed no detectable amounts of sulphite present in peas. Considering the detection limit of the method, this indicates that the steady state level in plant tissues is below 4 x 10(-5)M sulphite. Only in pea plants exposed to very high SO(2)-doses of 2.6-26mg m(-3) for 12-48 h, was sulphite recorded. We conclude from our results that sulphite dioxide, taken up by pea plants, is very effectively removed by enzymic and non-enzymic processes, and this 'detoxification' prevents accumulation of sulphite in the plant tissue, and so only very small amounts of sulphite are to be expected in SO(2)-damaged plant material. The possible role of very low sulphite concentrations in plant tissues is discussed.

Journal Article↗

PubMed1986

Relationships between respiratory activity and water-soluble sulfhydryl content of Norway spruce needles.

The rate of respiration of spruce needles was affected by the level of foliar glutathione. At 37 degrees C the rate of respiration increased with increasing water-soluble sulfhydryl content up to 1.3 micromol g(-1) fresh weight. Higher thiol concentrations inhibited the rate of respiration. At 25 degrees C no relationship was observed between glutathione content and rate of respiration. It was concluded that the mechanism by which SO(2) affects plants is temperature dependent.

Journal Article↗

PubMed1981

[On the evaluation of health factors in high-rise buildings 1. Behaviour of some environmental factors (author's transl)].

None of the test series carried out with completely different parameters (summation measurements of different type for SO2, fluorine, chlorides as well as germ counts for air) have indicated that the people living on the higher floors of tower blocks are exposed to a greater burden than those living on lower floors. On the contrary, the chloride analyses and also ther germ counts made on the balconies showed that such tower blocks are exposed to dust and dirt swirling up from the streets from the second up to the sixth floor (max. pollution on the third floor). In the stairwell, the highest germ count was made on the ground floor, as was to be expected. Needless to say, these results apply only to the conditions prevailing here. Somewhat different results may be obtained in other places, under different conditions regarding location and building structure. However, the results clearly show that the assumption that the upper storeys of high-rise buildings are exposed to a higher burden cannot be generally valid with respect to the parameters used. This is the least that our results indicate.

Air Microbiology↗