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Biomedical subjects

E Grün

Publications and source records attributed to E Grün.

At least 19 recordsLinked to original sources
PubMed2002

[The stability of progesterone in feces of different wild animal species kept in a zoological garden].

Methodical investigations were carried out to monitor especially in what respect external factors (dry mass of faeces, time point of freezing, duration of storage of the frozen samples, multiple defrosting of the samples) influence the progesterone concentration of the faeces of several wild animal species (Baringo giraffe, Black rhinoceros, Dama gazelle, Mountain goat) living in a zoological garden. With reference to one animal species the dry mass of the faeces showed only small variations. Therefore, it is possible to estimate comparable progesterone levels in several faecal samples of the same animal species without drying the samples. In all cases the progesterone concentration was increased after 24 and 48 hour storage of the faecal samples at room temperature compared with samples frozen directly (significant differences for giraffes and rhinoceroses). Samples of rhinoceroses and gazelles showed no significant changes of their progesterone concentration after a long time of storage (one and three months) in the freezing state (-20 degrees C). On the other hand, in faeces of giraffes with high progesterone levels a significant decrease of the initial level was pointed out. In comparison of single and multiple defrosting of the faecal samples, the latter caused a decrease of the progesterone concentration of the faeces of all animal species investigated (significant differences for rhinoceroses and gazelles).

Animals↗
PubMed2000

Growth and form of planetary seedlings: results from a microgravity aggregation experiment.

The outcome of the first stage of planetary formation, which is characterized by ballistic agglomeration of preplanetary dust grains due to Brownian motion in the free molecular flow regime of the solar nebula, is still somewhat speculative. We performed a microgravity experiment flown onboard the space shuttle in which we simulated, for the first time, the onset of free preplanetary dust accumulation and revealed the structures and growth rates of the first dust agglomerates in the young solar system. We find that a thermally aggregating swarm of dust particles evolves very rapidly and forms unexpected open-structured agglomerates.

Models, Theoretical↗
PubMed1999

Deflection of the local interstellar dust flow by solar radiation pressure.

Interstellar dust grains intercepted by the dust detectors on the Ulysses and Galileo spacecrafts at heliocentric distances from 2 to 4 astronomical units show a deficit of grains with masses from 1 x 10(-17) to 3 x 10(-16) kilograms relative to grains intercepted outside 4 astronomical units. To divert grains out of the 2- to 4-astronomical unit region, the solar radiation pressure must be 1.4 to 1.8 times the force of solar gravity. These figures are consistent with the optical properties of spherical or elongated grains that consist of astronomical silicates or organic refractory material. Pure graphite grains with diameters of 0.2 to 0.4 micrometer experience a solar radiation pressure force as much as twice the force of solar gravity.

Cosmic Dust↗
PubMed1998

Capture of interplanetary and interstellar dust by the jovian magnetosphere.

Interplanetary and interstellar dust grains entering Jupiter's magnetosphere form a detectable diffuse faint ring of exogenic material. This ring is composed of particles in the size range of 0. 5 to 1.5 micrometers on retrograde and prograde orbits in a 4:1 ratio, with semimajor axes 3 < a < 20 jovian radii, eccentricities 0. 1 < e < 0.3, and inclinations i less, similar 20 degrees or i greater, similar 160 degrees. The size range and the orbital characteristics are consistent with in situ detections of micrometer-sized grains by the Galileo dust detector, and the measured rates match the number densities predicted from numerical trajectory integrations.

Cosmic Dust↗
PubMed1998

Evidence of the existence of alpha 1B-adrenoceptors on hepatocytes of domestic fowl (Gallus domesticus).

In liver cell membranes of laying hens alpha 1-adrenergic receptors were characterized using 3H-prazosin. Specific binding was saturable and indicative of a single class of high-affinity binding sites with a KD of 0.40 +/- 16 nM and a Bmax of 390 +/- 38 fmol/mg membrane protein. Preincubation of membranes with chlorethylclonidine significantly diminished the binding of 3H-prazosin (Bmax = 99 +/- 14 fmol/mg membrane protein). Furthermore, competition experiments revealed a rank order of prazosin >> phentolamine = oxymetazoline >> WB 4101, with Ki values of 0.71 +/- 0.62, 20 +/- 6, 32 +/- 13, and 119 +/- 48 nM, respectively. These results suggest the existence of alpha 1B-adrenergic receptors in hen liver cell membranes.

Animals↗
PubMed1996

Solar wind magnetic field bending of Jovian dust trajectories.

From September 1991 to October 1992, the cosmic dust detector on the Ulysses spacecraft recorded 11 short bursts, or streams, of dust. These dust grains emanated from the jovian system, and their trajectories were strongly affected by solar wind magnetic field forces. Analyses of the on-board measurements of these fields, and of stream approach directions, show that stream-associated dust grain masses are of the order of 10(-18) gram and dust grain velocities exceed 200 kilometers per second. These masses and velocities are, respectively, about 10(3) times less massive and 5 to 10 times faster than earlier reported.

Cosmic Dust↗
PubMed1995

[Artificial lactation induction in 12- to 19-month-old heifers with regard to the behavior of the concentration of sex hormones and lactogenic proteohormones in the blood plasma].

In 24 prepubertal heifers the lactation was artificially induced by two different methods of hormone application. The changes in milk yield and the concentrations of estradiol-17 beta (E), progesterone (P), prolactin, somatotropin and insulin-like growth factor I in blood plasma during the first 55 days of lactation were analyzed. Depending on the age, the animals were divided in three experimental groups (EG) of eight animals each: 12 months old (EG I), 15 months old (EG II) and 19 months (EG III). Four animals of each EG were treated similarly: group E and P, which was injected by estradiol benzoate and P for 7 days, or group E, which received only estradiol benzoate for 10 days. The oldest heifers (EG III) showed an induction rate of 100% with E and P treatment and of 75% with E alone. On the other hand, in heifers of EG I and EG II the induction rate was only 50% irrespectively of the treatment. The animals of EG III had the highest milk yield. The daily milk yield on the 50th day of lactation was 7.0 kg and 4.0 kg in group E and P or group E, respectively. Comparable levels in 15 months old heifers (EG II) were 4.8 kg and 1.4 kg, and in 12 months old heifers (EG I) 2.5 kg and 2.5 kg. The changes of the concentrations of the hormones in blood plasma are demonstrated in diagrams, their effect on the milk production is discussed.

Animals↗
PubMed1995

[The composition of milk after artificial lactation induction in 12- to 19-month-old heifers].

In 24 prepubertal heifers the composition of milk after an artificial induction of lactation was investigated. Depending on the age, the animals were divided in 3 experimental groups (EG) of 8 animals each: 12 months old (EG I), 15 months old (EG II), and 19 months old (EG III). Four animals of each EG were treated similarly: either with estradiol benzoate and progesterone for 7 days (group E and P) or only with estradiol benzoate for 10 days (group E). During the first 18 days of lactation the protein and lactose content of the milk showed similar changes compared to the period of milk maturation during natural lactation of same duration. However, a typical colostral period with high concentrations of immunoglobulins in the milk was not observed. After the artificial induction of lactation, in the period until to the 53rd day of lactation no age dependent differences in the composition of milk were found, except whey proteins. Formation of milk substances, which are synthesized in the mammary gland, is much more induced by treatment with E and P than by treatment of E alone, with the exception of caseins.

Animals↗
PubMed1995

[Lactoperoxidase activity and thiocyanate content of milk from cows with mastitis in different lactation stages].

During three lactational periods (start, middle and end of lactation) of 35 milk cows suffering from mastitis and compared with 34 healthy milk cows of comparable milk production the activity of lactoperoxidase (LPO) and the SCN-content of the milk in each udder quarter were determined. Both components showed no alterations in the subclinical form of the disease. There exists a decrease of the LPO activity in the secretion of ill udder quarters, which will be distinct only in the individual animal and a strong increase of the SCN-content, which is also significant in comparison with the milk of healthy cows.

Animals↗
PubMed1995

[Thiocyanate content in blood plasma, udder lymph and milk from healthy cows and cows with mastitis].

After storage for more than one year the SCN(-)-content of udder lymph was not changed seriously, but in blood serum and mainly in milk, there is an evident decrease. In lactational cows with healthy udders the SCN(-)-content of blood plasma is higher than in milk (in average twice). There is no difference of the SCN(-)-content of the four udder parts of healthy cows. Decrease of milk production (10. to 13. lactational month) causes an increase of the SCN(-)-content of the milk, it is not changed in subclinical mastitis. In lactational cows with healthy udders the SCN(-)-content of udder lymph is nearly triple higher in average than in milk of the corresponding quarter of the udder. The existence of a common compartment of SCN- in blood and udder lymph is assumed, which is separated from them of the milk by the blood udder barrier.

Animals↗
PubMed1993

[Does the administration of derivatives of vitamin D to dairy cows in late pregnancy for the prevention of parturient paresis affect the maternal-fetal mineral metabolism?].

Intramuscular injection of 1 alpha-hydroxyvitamin D3 (with or without 25-hydroxyvitamin D3) to highly pregnant dairy cows caused a significant increase of ionized calcium in blood and of total calcium and inorganic phosphate with a concomitant decrease of magnesium in blood plasma 3,5 +/- 1,9 days later (resp. 12-48 h a.p.). This brought about a higher Ca level at parturition preventing parturient paresis. The changes of maternal mineral and vitamin D status had no effect on the mineral concentrations of blood in newborn calves. However, the increase in calcium and phosphate concentrations in maternal blood after injection was accompanied by an increase of the minerals in the amniotic fluid reflecting their strong reciprocal exchange. On the other hand, the composition of allantoic fluid showed no significant changes. Therefore, analysis of both fetal fluids does not refer to disorders of fetal mineral metabolism. As a consequence, there seems to be no potential risk of intoxication after a prepartal injection of the substances to the mother for their offspring.

Animals↗
PubMed1992

Ulysses dust measurements near Jupiter.

Submicrometer- to micrometer-sized particles were recorded by the Ulysses dust detector within 40 days of the Jupiter flyby. Nine impacts were recorded within 50 Jupiter radii with most of them recorded after closest approach. Three of these impacts are consistent with particles on prograde orbits around Jupiter and the rest are believed to have resulted from gravitationally focused interplanetary dust. From the ratio of the impact rate before the Jupiter flyby to the impact rate after the Jupiter flyby it is concluded that interplanetary dust particles at the distance of Jupiter move on mostly retrograde orbits. On 10 March 1992, Ulysses passed through an intense dust stream. The dust detector recorded 126 impacts within 26 hours. The stream particles were moving on highly inclined and apparently hyperbolic orbits with perihelion distances of >5 astronomical units. Interplanetary dust is lost rather quickly from the solar system through collisions and other mechanisms and must be almost continuously replenished to maintain observed abundances. Dust flux measurements, therefore, give evidence of the recent rates of production from sources such as comets, asteroids, and moons, as well as the possible presence of interstellar grains.

Dust↗
PubMed1992

[Comparative studies of diagnostically significant enzymes in plasma, udder lymph and milk of healthy cows and cows with udder diseases].

Different secretions (colostrum, milk, dry udder secretion) of every quarter, peripheral lymph from superficial lymph vessels of the mammary gland and blood from the V. epigastrica superficialis were obtained in 43 cows at different stages of lactation. In these samples the activity of 5 enzymes (LDH, NAG, AP, LAP, GGT) was determined. Levels of LDH and NAG were highest in blood plasma and udder lymph. Levels of LAP, AP and GGT were highest in milk increasing in this order. LDH, NAG, AP and LAP were correlated in both compartments. Changes of the functional state (dry or colostral period) and tissue disturbances of the mammary gland were accompanied by marked changes of enzyme activity in the secretions, but were without obvious influence on enzyme levels in blood plasma and udder lymph.

Animals↗
PubMed1985

[The physiological and diagnostic importance of lysozyme in cow's milk].

The enzyme lysozyme (earlier muramidase) is one of the factors of the non-specific defense mechanism of the mammary gland. It represents a regular constituent of milk, which despite its very low content in milk determines the health condition of the udder and its defending ability against infectious agents. Therefore, a review is given on the factors influencing the lysozyme content in bovine milk, its significance for the bactericidal effects of milk, its changes in mastitis and the resulting possibility of its introduction in diagnostic work, and the therapeutical use of milk rich in lysozyme.

Animals↗
PubMed1984

[Activity of gluconeogenetic enzymes in swine myocardium and skeletal muscles].

The activity of the gluconeogenic enzyme phosphoenolpyruvate carboxykinase (PEPCK) was determined radiometrically in heart and skeletal muscle (M. semitendinosus) of 21 fetuses of the last third of gestation (80th-112th day), 17 piglets from birth until the 9th day of life and 7 fattening pigs. Simultaneously the activity of the enzymes glucose-6-phosphatase (G6Pase) and fructosebisphosphatase (FDPase) was measured colorimetrically in heart and skeletal muscle of piglets and in skeletal muscles of fattening pigs. Heart and skeletal muscle have only a low PEPCK activity. During the last third of gestation PEPCK in heart remains on a constant level, which can be demonstrated also in fattening pigs, but doubled immediately after birth. During the last two weeks of gestation, at birth and during the first days of life the PEPCK activity in the skeletal muscle is 3-fold higher than at the 80th day of gestation and in fattening pigs. G6Pase and FDPase activity of the heart remains at a constant level during the first days of life. It was impossible to detect G6Pase in the skeletal muscle of piglets. The specific FDPase activity of the skeletal muscle remains constant also postnatally. In fattening pigs skeletal muscles with different types of fibres have the same FDPase and PEPCK activity.

Age Factors↗