M. Juráni

Melatonin content in plasma and large intestine of patients with colorectal carcinoma before and after surgery

Abstract: The distinct melatonin rhythm with higher concentrations during the darktime was found in plasma of both control patients and patients with colorectal carcinoma. Moderate surgery did not induce any changes in plasma melatonin levels, but a pronounced increase in both the day‐ and nighttime melatonin concentrations was found after surgical treatment for colon cancer. The melatonin content in the tumor tissue did not differ from that in the proximal and the distal parts of the resected gut, which were without signs of malignant changes. Neither concentrations of serotonin nor 5‐hydroxyindole acetic acid differed among analyzed parts of the gut. Daytime melatonin concentrations in gut tissue (314.7 ± 87.8 pg/g of wet tissue) were more than ten times higher than the daytime levels in circulation. It was hypothesized that increased levels of this hormone in the gastrointestinal tract may play an important protective role against the development of colorectal cancer via stimulation of the immune system, protection against free radicals, and interaction with fatty acid uptake and metabolism.

Chicks from a high and low feather pecking line of laying hens differ in apomorphine sensitivity

Proactive rodents show a larger behavioral response to apomorphine (APO) than reactive copers, suggesting a more sensitive DA system in proactive individuals. Previously, chicks from a high feather pecking (HFP) and low feather pecking line (LFP) have been suggested to display a proactive and reactive coping strategy, respectively. Therefore, at approximately 4 weeks of age, the behavior of 48 LFP and 48 HFP chicks in response to an APO injection was studied using an open field. Another objective of the present study was to determine whether behavioral variation (in an open field) between HFP and LFP birds, after APO injection, is also reflected by variation of D(1) and D(2) receptor densities in the brain. Receptor binding capacities were assessed by measuring specific binding of tritiated D(1) and D(2) receptor ligands in different regions of the brain of control HFP and LFP chicks. In the present study, it is shown that indeed HFP chicks display a more enhanced behavioral response to acute APO treatment (0.5 mg/kg BW) than LFP birds in an open field. This difference was not reflected by variation of D(1) and D(2) receptor densities in the brain between both lines.

Plasma thyroid hormone and growth hormone patterns in precocial Japanese quail and altricial European starlings during postnatal development

Plasma concentrations of thyroid hormones (TH) and growth hormone (GH) during postnatal development in the precocial Japanese quail (Coturnix japonica), and the altricial European starling (Sturnus vulgaris) were measured. Developmental changes in plasma TH found in the starling, differ considerably from those detected in quail. In quail rather high triiodothyronine (T3) values were measured during the first few days after hatching. Subsequently a steady decrease of plasma T3, to adult levels, was observed. Thyroxine (T4) concentrations did not change significantly during the period studied. In starlings, on day 1, plasma T3 was low and T4 was at or below the assay detection limit. An increase in concentrations of both hormones occurred between day 1 and day 5 after hatching. A gradual increase of T4 occurred afterwards, while plasma T3 levels remained nearly constant during this growing period. Plasma GH concentrations showed a similar pattern in both species. There was an increase during first days after hatching and GH concentrations peaked at day 7 in quail and day 5 in starlings. A subsequent decrease was observed in both species. Although the GH profiles in species studied were comparable, there were noticeable differences in their growth rates. Thus different developmental strategies have been reflected in different developmental patterns of TH in precocial Japanese quail and altricial European starling whereas developmental changes of GH levels were similar in both species.

Effect of Rooibos tea (Aspalathus linearis) on chick skeletal muscle cell growth in culture.

Rooibos tea (RT) extract contains natural antioxidants and scavenging agents. We investigated the effects of different concentrations of RT extract in medium on growth and changes of growth parameters of cultured chick embryonic skeletal muscle cells. Presence of 2, 10 and 100% of RT extract in the culture of primary cells significantly inhibited cell proliferation. The inhibition of cell growth reflected on decreased DNA, RNA and protein contents in primary cell culture and fibroblasts and myoblasts. The ability of the primary cells, fibroblasts and myoblasts to synthesize DNA and protein in the presence of RT extract, measured as an amount of [3H]thymidine and [3H]leucine incorporated into DNA and de novo synthesized protein, corresponded with decreasing DNA and protein contents in all three cell types. The inhibition effect of RT rose with increasing concentration of the tea extract in the culture medium. Ornithine decarboxylase activity was significantly affected only by 100% RT extract in every examined cell types. These results suggest that the inhibitory effect of RT extract on the growth of primary cells, fibroblasts and myoblasts is due to the potent scavenging activity of the RT extract.

Effect of restraint upon hypothalamic and adrenal catecholamines in Japanese quail.

1. Changes in catecholamine concentration after periods of restraint up to 48 h in male Japanese quail have been measured. 2. Hypothalamic catecholamines decreased after 10 min restraint. Dopamine concentration increased after 4 h and persisted to 48 h. 3. Plasma catecholamines increased after 10 min, remained high for 2 h and then decreased despite continuing restraint. Catecholamine content of adrenals slightly decreased during restraint. 4. The activity of adrenal phenylethanolamine-N-methyl transferase increased from the 4th hour of restraint.

INFLUENCE OF MELATONIN ON CHICK SKELETAL MUSCLE CELL GROWTH

Melatonin as a highly lipophilic compound readily enters all subcellular compartments and acts by various mechanisms. In the present study, we investigated the effects of different concentrations of melatonin in medium (physiological and supraphysiological doses) at two treatment times (48 and 120 hr) on growth and changes of growth parameters of cultured chick embryonic skeletal muscle cells. The physiological doses of melatonin (100 pg to 10 ng/ml of medium) stimulated proliferation of cells and raised DNA, RNA protein contents and an incorporation of [3H]leucine into cell protein after 48 hr of treatment. The prolongation of exposure to melatonin in the physiological dose to 120 hr or an increase of melatonin dose to a supraphysiological one evoked the inhibition of cell growth and proliferation by decreasing the number of cells and the amount of labeled leucine incorporated into cell protein. Results demonstrate that melatonins action in these cells is time and dose dependent.

Hypergravity‐induced Increase in Plasma Catecholamine and Corticosterone Levels in Telemetrically Collected Blood of Rats during Centrifugation

Rats subjected to various accelerations (+G) exhibited increased levels of plasma epinephrine (EPI), norepinephrine (NE), and corticosterone. However, the collection of blood was performed after a centrifugation finished, and therefore the levels could be affected by the process of deceleration. The aim of this study was to evaluate plasma EPI, NE, and corticosterone levels in blood collected directly during centrifugation after reaching different G (2–6), using newly developed remote‐controlled equipment. Animals placed into the centrifuge cabins had inserted polyethylene tubing in the tail artery, which was connected with a preprogrammed device for blood withdrawals. Plasma EPI, NE, and corticosterone levels were measured at different time intervals of hypergravity of 2–6G. Plasma EPI levels showed a huge, hypergravity‐level–dependent increase. After the last blood collection was completed during hypergravity, the centrifuge was turned off and another blood sampling was performed immediately after the centrifuge stopped (10 min). In these samples, plasma EPI showed significantly lower levels compared to centrifugation intervals. Plasma NE levels were significantly increased after 6G only. The increase in plasma corticosterone was dependent on level of G, however after the centrifuge stopped, corticosterone levels remained elevated. Thus, our data show that hypergravity highly activates the adrenomedullary and hypothalamo‐pituitary‐adrenocortical systems, whereas the sympathoneural system is activated only at high hypergravity. Immediately after centrifugation is over, EPI levels quickly return to control values. Our technique of blood collection during centrifugation allows assessment of the real hormonal levels at the particular hypergravity value.

Effect of rooibos tea ( Aspalathus linearis ) on Japanese quail growth, egg production and plasma metabolites

1. Birds have been proposed as a suitable model for studies on ageing because of their long life in comparison with similar-sized mammals. However, some weak fliers, such as Galliformes, are the exception to this rule. The aim of the present study was to determine the effects of the treatment with rooibos tea (Aspalathus linearis), a natural source of flavonoid antioxidants and compounds with phyto-oestrogenic activity, on postnatal development and egg production of aged Japanese quail (Coturnix coturnix japonica). 2. Substitution of drinking water with traditional rooibos tea or diet supplementation with ground rooibos tea affected body weight of Japanese quail up to 100 d of age. The body weight of males drinking rooibos tea or eating rooibos-supplemented food decreased significantly. There was a trend toward increased body weight of tea drinking females and a significant increase in the body weight of hens fed the rooibos-supplemented diet. Although rooibos treatment did not significantly increase egg production in young hens, the decrease in egg production of rooibos-treated aged hens (360 d of age) was significantly reduced, regardless of the egg production levels (high—80%; low—20%) before the treatment. 3. The results suggest that treatment with rooibos tea positively affected body weight and egg production in quail hens and prolonged the productive period of aged animals. Further studies would be needed to address the question whether these effects are due to the antioxidant or phyto-oestrogenic activities of rooibos.

Selection of Japanese Quail for Resistance to Hypodynamy and Physiological Consequences of Selection

Ivanova I. Ye., T. A. Derendiayeva, G. I. Meleshko, Yeo Ya. Shepelev: Higher Plants in a Biological Life SupportSystemfor Man. Acta vet. Bmo 1996,65: 27-32. A model of human biological life support system (BLSS) was created with a photoautotrophic link including unicellular algae and higher plants having an equal oxygen production. This system model supported the vital activities of two people at the biomass regeneration of 92% from that consumed by them. The plant cultures studied were wheat grown on 11.25 m2 (of a total 15 m2) and several vegetable species. The total photosynthetic productivity of the plants was high, stable over the studied time span, and independent on the composition of the system. However, the grain productivity of wheat decreased periodically, and during certain harvests it decreased to almost zero. A detailed analysis revealed that this decrease was not caused by any of the systems adjacent links as a similar decrease in yield was also found in the control period with an autonomous growth of the plants in a closed volume of a chamber. Inclusion of bigher plants into BLSS led to a considerable improvement od food supply regeneration for man as compared to the previous model with only 26% regeneration effect. This inclusion did not exert any marked effect upon the general closure of the cycle. However, the biological value of the food for man was increased dramatically. This improvement is the main goal of designing and operating such BLSS systems. Regeneration. ecosystem. photosynthesis, photoautotroph link, unicellular algae. higher p.lants The prospect of long-teon existence of man outside the Earths biosphere (interplanetary flights, lunar and planetary bases) is connected with creating an artificial environment with the help of regenerating it from the products of vital activity. This environment must correspond to the evolutionarily conditioned biological needs of the humans and to provide their lives for generations. The fact of adaptive biology shows that the full-value environment for humans and other terrestrial organisms is the natural environment of the Earth. In order to recreate that environment artificially it is necessary to reproduce the mechanisms existing on Earth, i. e. to foon closed ecological systems including man. The lack of our knowledge about the natural environment of the humans prevents us from reproducing it by non-biological means, even if it were possible. The investigation of the problem of creating biological life-support systems (BLSS) of man began as early as in the 60ies. By the present time, experimental BLSS models have been created with different structures and different degrees of the cycle closure. , The creation of the systems was based on the ecological concept according to which strategy and tactics were worked out providing the organisms and populations were studied and then united into biocenoses, including also humans. The main method of solving the problem was the method of experimental modelling from the simple to the complex (Rashevski 1966).

Effects of thyroid hormones on chick embryo muscle cell culture.

The importance of thyroid hormones (TH) in the normal development of muscles has been repeatedly postulated. The effects of physiological TH doses on ornithine decarboxylase (ODC) and protein synthesis in muscle cells have been studied using cell cultures prepared from 11-day-old chick embryos. Triiodothyronine nuclear receptors in primary muscle cell culture were characterized on the basis of the specific binding analysis as a single receptor class with the equilibrium dissociation constant Kd = 1.2 +/- 0.4 x 10(-10) mol/l and binding capacity Bmax = 0.21 +/- 0.09 fmol/micrograms DNA. While the physiological amounts of both triiodothyronine (T3) and thyroxine (T4) stimulated ODC activity after 2 hr of treatment, only T3 had the same stimulatory effect after 4 hr of treatment. Twenty-four hour exposure of muscle cell culture to TH did not change ODC activity. The incorporation of [3H]leucine into proteins was elevated only after 120 hr incubation in the presence of T4. Application of T4 caused also an increase in the protein content after 24 hr.