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Biomedical subjects

H Dorner

Publications and source records attributed to H Dorner.

11 recordsLinked to original sources
PubMed1996

V+ fibronectin mRNA is increased in the brains of aged rats: effect of food restriction.

Food restriction increases life-span in rodents. With regard to the central nervous system, underfeeding has been shown to have beneficial effects on synaptic transmission in old rats. However, the molecular events underlying functional changes in the brains of food-restricted rats are largely unknown. In the present study the levels of fibronectin mRNA containing the alternatively spliced segment V (FN-V+) as well as the levels of FN mRNA containing the alternatively spliced segment EIIIB (FN-EIIIB+), were examined by RNA gel blot hybridization in the brains of 3-day-old, 24-day-old, 10-month-old, 18-month-old, 30-month-old ad libitum (AL) fed, 30-month-old food-restricted (FR), and 35-37-month-old, FR rats. The hybridization signal for the FN-EIIIB+ mRNA was relatively abundant at early postnatal stages but very few transcripts were detected in the brains of adult, AL rats. The transcripts coding for FN-V+ mRNA were moderately expressed in the brains of 3-day-old, 24-day-old, 10-month-old, and 18-month-old rats. However, the FN-V+ mRNA signal was then prominently increased (approx. 3-fold) in the brains of the 30-month-old, AL rats vs. 10-month-old, AL rats, and further increased (approx. 2-fold) in the brains of 30-month-old, FR, as compared to 30-month-old, AL rats. However, the levels of FN-V+ mRNA were slightly decreased in the brains of very old (35-37-month) FR rats vs. 30-month-old FR rats. The distribution of fibronectin messenger RNA and protein was also investigated by non-radioactive in situ hybridization and immunohistochemistry, respectively. The most prominent expression of FN-V+ messenger RNA was seen in neurons of the hippocampus, including the granule cells of the dentate gyrus, and in layers III and V of the cortex of 30-month-old, FR rats. FN immunostaining closely paralleled the distribution of FN mRNA and was confined to the neuronal cell periphery. The upregulation of fibronectin gene expression upon exposure to glucocorticoids is well documented. Prolonged food restriction, acting as a stress factor, combined with decreased plasticity of glucocorticoid regulatory responses in the aged rats could cause an increase in the levels of FN mRNA and protein in the brains of old, FR rats. Since FN has been shown to provide an adhesive substrate for extending neurites, we conclude that food restriction may potentiate synaptic plasticity, via glucocorticoid receptor binding elements of the FN gene, in the brains of old rats.

Aging↗
PubMed1996

[Sports as a preventive and rehabilitational measure for the elderly].

Numerous studies have shown a negative correlation between physical activity and cardiovascular morbidity/mortality. On the basis of the results of these studies, the following prophylactic recommendations have been worked out: vigorous physical exercise resulting in an increase in energy consumption of at least 200-300 kcal/day or 2000 kcal/week. In addition, experimental research in the field of sports medicine has shown that besides calorie consumption, minimal qualitative and quantitative requirements must also be met if training is to have a preventive effect. Here, the maximum oxygen uptake capacity (the international reference parameter for physical fitness) is of decisive importance. Against this background, participation in a training program offering for 30 min at least 2-3 times a week is recommended. Many studies have shown the effectiveness of such training programs in both, primary and secondary prevention of various cardiovascular diseases, and in the area of geriatric rehabilitation.

Aged↗
PubMed1996

Training influence on age-dependent changes in the gait of rats.

Stride length, stance width and gait symmetry were measured as parameters of gait analysis in young (5 months) and old (28 months) Sprague-Dawley rats following 3 months of treadmill running as well as in sedentary controls. Stride length decreased significantly with age and increased significantly following training in both young and old rats. Means of stance width increased significantly with age, but were unaffected by training. Gait symmetry declined with age; however, treadmill running counteracted the decline of gait symmetry. It was concluded that treadmill running compensates for or prevents age-related changes in the neuromuscular function of rats, which lead to gait deterioration.

Aging↗
PubMed1995

Fibronectin mRNA (FN-V95+) is increased in the liver of old Sprague-Dawley rats: effect of food restriction.

Because fibronectin (FN) mRNA has been shown to be increased in the brain of old rats and during in vivo and in vitro aging of both endothelial cells and fibroblasts, it was of interest to determine what effect age and caloric restriction have on the ability of liver cells to express FN mRNA. The prevalence of fibronectin mRNA containing the alternatively spliced variant V95 (FN-V95) was examined by RNA gel blot hybridization in the liver of 10-mo, 18-mo, 30-mo ad lib-fed (AL) and 30-mo food-restricted (FR) rats. The transcripts coding for FN-V95 mRNA were well expressed in the liver of 10-mo and 18-mo-old rats. The hybridization signal then increased (1.3-fold, p < .05) in the liver of 30-mo AL rats vs 10-mo-old rats. However, the prevalence of FN-V95 mRNA was dramatically decreased (approximately 4.5-fold, p < .01) in the liver of 30-mo food-restricted rats as compared to 30-mo-old AL rats. The distribution of FN-V95 mRNA was also investigated by non-radioactive in situ hybridization (ISH) on liver frozen sections. The hybridization signal for FN-V95 mRNA was evenly distributed among liver cells of 10-mo and 18-mo-old rats, while weak hybridization signals were sparsely scattered on liver sections derived from 30-mo-old FR rats. In contrast, strong hybridization signals showing a localized distribution were detected on liver sections obtained from 30-mo-old AL rats. Histologic examination of cryostat sections also revealed a massive accumulation of lipid droplets in the liver of 30-mo-old AL rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1995

Influence of age, treadmill running, and food restriction on plasma fibrinogen concentration and expression of gamma chain mRNA in female Sprague-Dawley rats.

Plasma fibrinogen concentration and expression of mRNA encoding the gamma-chain of fibrinogen were determined in female Sprague-Dawley rats aged 10, 21 and 30 months. Both parameters increased significantly with age in a parallel fashion. Food restriction was able to reduce the age-dependent increase of both plasma concentration and gene expression to levels below young controls. On the other hand, long-term treadmill running failed to influence the plasma fibrinogen concentration. From these results we conclude that the plasma fibrinogen concentration increases with age due to an increased fibrinogen biosynthesis.

Aging↗
PubMed1993

Effects of exercise on myocardial adenylate cyclase and Gi alpha expression in senescence.

The present study investigated the influence of physical training on alterations leading to reduced adenosine 3',5'-cyclic monophosphate (cAMP) formation in aged myocardium. Senescent (28-mo-old) rats underwent a moderate treadmill exercise program and were compared with sedentary controls. In myocardial membranes from aged rats, isoprenaline-stimulated adenylate cyclase activity (AC) was reduced compared with that in young animals and was accompanied by an increase of pertussis toxin substrates (17.5%) and an increased amount of immunodetectable inhibitory guanine nucleotide-binding proteins (Gi alpha; 72%). Physical training reduced the amount of Gi alpha proteins (30-35%) in young and old animals and enhanced only isoprenaline-stimulated AC in the aged rats, and basal and 5'-guanylylimidodiphosphate [Gpp(NH)p]- as well as isoprenaline-stimulated AC in young rats. Physical training or aging had no effect on the number of beta-adrenoceptors or m-cholinoceptors or on forskolin-stimulated AC in either group. The amount of immunodetectable stimulatory guanine nucleotide-binding proteins (Gs alpha) using an antiserum raised against the COOH-terminal peptide of Gs alpha (RMHLRQYELL) was unchanged in either condition. It is concluded that enhanced Gi alpha expression might be one mechanism leading to depressed cAMP formation in aged myocardium. Depressed AC and increased Gi alpha can be partially reversed by physical training, especially in young myocardium. Gi alpha might serve as a regulator of cardiac AC in a variety of physiological and pathophysiological situations in the absence of beta-adrenoceptor changes.

Adenylate Cyclase Toxin↗
PubMed1990

The effect of a garlic preparation on the composition of plasma lipoproteins and erythrocyte membranes in geriatric subjects.

This study evaluated the effect of a dried garlic powder preparation, standardised to 1.3% alliin, on the composition of plasma lipoproteins and erythrocyte membranes. Forty volunteers, aged 70 years and over, took 600 mg of garlic powder per day for three months. In participants with initially normal plasma cholesterol levels (CH less than 200 mg/dl; n = 11) after three months of garlic tablet administration, little or no change in CH values was registered, as for most of the other parameters. In contrast, in volunteers with initially elevated CH levels (CH greater than 200 mg/dl, n = 29), the CH levels were reduced by -7.7% (p less than 0.001). This reduction took place primarily in the esterified cholesterol fraction (-12%, p less than 0.001), whereas free cholesterol concentrations were not altered significantly. Triglycerides (-15.9%, p less than 0.05) and plasma choline phospholipids (-4.6%, p less than 0.01) were also reduced. No change of the plasma LDL-CH to HDL-CH ratio was observed in this group. Based on the weight of lyophilised, haemoglobin-free erythrocytes, the mean membrane concentration of phospholipids and cholesterol in the total cohort (n = 40) increased by 5.7% (p less than 0.001) and 6.1% (p less than 0.01), respectively. These increases were more pronounced the lower the body mass indices (kg/m2) were, and the longer the duration of garlic administration was. The molar ratio of membrane phospholipids to cholesterol remained unchanged. The results are discussed with regard to a possible role of the garlic-induced membrane effects in the plasma lipid-lowering potency of garlic and preparations made from it.

Aged↗
PubMed1975

[Sephadex induced inflammation in rats (author's transl)].

QUESTION: A single s.c. injection of Dextran is very suitable in producing an inflammatory response in the rat. The Dextran edema has become a standard method. It seems not uhlikely that Sephadex, the Dextran gel widely used in the gelchromatography may have a similar effect. Sephadex, because of its physiochemical properties, would offer some advantages in the studies of inflammatory reactions. But first of all the following questions have to be answered: 1. Does one single s.c. injection of Sephadex produce an inflammation at all and what are the characteristics on the microscopical level? 2 Does it make any difference if Sephadex of different types are injected? MATERIAL AND METHODS: Male and female Wistar rats (100-250 g) in groups of 5 animals each. Diet: Rat pellets "Tagger" and tap water ad libitum. Sephadex (Pharmacia Fine Chemicals) of the types G-25 m, G-50 m, G-100, and G-200 were soaked in 0.9% saline for the prescribed time and afterwards preserved until the Sephadex gel had settled on the bottom of the vessels. 1 ml of this Sephadex gel slurry each were subcutaneously injected to the shaved dorsal skin of the rats (right below). At different intervals (3, 6, 24 and 72 hours: 6, 14, 20 and 28 days) the Sephadex depot and the surrounding tissue were exstirpated and examined histologically. During all the procedures the animals were subjected to ether anesthesia. From the tissue samples frozen sections (Kryocut, -30 degrees C) were prepared and stained with hematoxylin and eosin or after van Gieson. Moreover, several preparations were stained after Pappenheim and Weigert (fibrin) or with PAS and toluidine blue. For recording of probable differences in the effect of the particular Sephadex types always 2 values were determined histometrically. The number of exudate cells emigrated between the Sephadex beads within the area of an ocular-net (edge length 1.66 mm) were counted at 500-fold magnification. Furthermore, the number of eosinophils was determined by the technique. However, because of poor occurrence the eosinophils were counted in 10 fields of view. Tests with Sephadex G-10 were omitted as preliminary tests had shown that it is not suitable for s.c. injections because of its gritty consistency (due to poor soaking properties). RESULTS: One single s.c. injection of Sephadex in the rat induces an acute inflammation. The exudative phase marked by a massive leucocytic infiltration (especially PMN leucocytes) is followed by the appearance of mononuclear leucocytes and fibroblasts after the 2nd day. The inflammation declines within approximately 3 weeks. Thereafter the Sephadex depot is encapsulated by a fibrous tissue. A chronic inflammation was never observed. In the microscopical aspect of the inflammation produced by the different types of Sephadex were detectable. The Sephadex lying in the tissue does not change its original shape, it is insoluble and is not disintegrated. The size of the particles prevents the transport into the blood or lymph vessels...

Animals↗
PubMed1975

[Histological studies on the antiphlogistic effects caused by natural antiinflammatory factors (author's transl)].

QUESTION: The dextran gel Sephadex causes a marked inflammatory response in rats when injected subcutaneously. This effect was used as a model of experimental inflammation. Sephadex and the resulting inflammatory exudate were gained and used again to study their antiphlogistic effects in the identical model. Histological reactions of the Sephadex induced acute inflammation were analyzed with and without presence of the exudate. MATERIAL AND METHODS: Male and female Wistar rats (100-250 g). Sephadex G-200 (Pharmacia Fine Chemicals). Sephadex B-200 (1 ml, swollen in 0.9% NaCl) was injected subcutaneously in the control group (C), whereas the experimental groups were injected with either untreated Sephadex taken from 1,3 and 5 days old inflammatory deposits (group A) or with Sephadex, extracted from those deposits but subsequently washed free by 0.9% NaCl (group B). Only the inner and not yet organized part of the Sephadex deposit was used in both experimental groups. In group A, B and C the histological effects were examined 24h after injection. The number of eosinophils amongst the exudate cells was counted. 100 mast cells of the perifocal region were examined in order to measure the percentage of degranulated cells. A smear differential count was performed using subepidermic parts of the Sephadex deposit. RESULTS: Sephadex injection caused a very marked inflammatory reaction which was studied extensively. Similar results were obtained either using fresh Sephadex or washed Sephadex from inflammatory deposits. However, Sephadex from inflammatory deposits without wash induced only mild inflammatory reactions. All signs of acute inflammation were less pronounced. Hence, the phlogistic efficacy of Sephadex is reduced by the simultaneous presence of exudate. The most significant antiphlogistic effects were seen when exudate containing Sephadex from 3 days old inflammatory deposits was used. The significance of soluble parts of the exudate in these antiphlogistic effects is discussed.

Animals↗
PubMedDate not supplied

A productivity study.

Although the study did not include all of the direct and indirect activities performed in the Processing Department, the study did provide data for the following conclusions. In analyzing the activities surrounding the collection of statistical data, it was determined that the manager was required not only to supervise, but to work in a staffing position. As a result, a supervisor was employed to assist the manager in supervising the daily operation of the department. This enabled the manager to fulfill the responsibility of overall direction of the Processing area. This study was a vehicle for building and maintaining pride and enthusiasm toward the achievement of high levels of performance in the department. The study was an instrument for establishing operational standards. By conducting a time study in each area, an exact amount of time required for decontamination, instrument processing and case cart assembly was determined. A specific time was determined for each activity, thereby providing a workload index. The study was the catalyst for developing an instrument manual with diagrams of instrument trays for increased accuracy and efficiency. Productivity studies play a significant role in establishing credibility between employee and employer in that both can establish mutual goals. Once performance is defined by measurable criteria, steps can be taken to focus on methods of improving productivity. By increasing efficiency and effectiveness, the department will attain "more bang for the buck."

Central Supply, Hospital↗