The biological activity of natural source tocopherols in chickens fed fresh or oxidized fat rich in linoleic acid

Three experiments were carried out with male broiler chickens reared from day- old to 6 weeks of age on semi-purified diets containing 10% fresh (Expt. 1 and 3) or oxidized (Expt. 2) re-esterified triglycerides with a fatty acid composition similar to that of soya bean oil containing increasing concentrations of either a mixture of d-alpha-, gamma-, delta-tocopherylacetate (d-tocopherols) of natural source or dl-alpha- tocopheryl acetate (dl-tocopherol). In Expt. 1 and 2 the mixture of d-tocopherols consisted of 35.7% d-alpha-, 45.3% d-gamma- and 19.0% d-delta-, while in Expt. 3 the distribution was 25.3% d-alpha-, 28.1% d-gamma- and 10.8% d-gamma- in 35.8% re-esterified triglycerides. The relative biopotency of d-alpha-: gamma-: delta-tocopherol was anticipated to be 100:25:1, whereas that of dl-alpha-tocopherol was 74% relative to d-alpha-tocopherol. The experiments demonstrate that the results obtained for the biological activity depend on the response parameters chosen. With respect to gain in weight, feed conversion, relative organ weight, packed cell volume (PCV), ELP (erythrocyte lipid peroxidation), plasma activities of glutamate-oxaloacetate-transaminase (GOT), creatine kinase (CK) and glutathione peroxidase (GSH-Px) and plasma Na+ concentration, the mixture of natural source tocopherols was identical to that of dl-alpha-tocopheryl acetate, although the concentration of alpha-tocopherol was only about one third of that of dl-alpha-tocopherol. Differences between natural source and synthetic tocopherols were expectedly observed with respect to plasma concentrations of alpha-, gamma-, delta-tocopherol. Differences between the two forms as to muscular dystrophy, in vitro haemolysis and potassium concentration in plasma were ambiguous. It is suggested that the function of d-alpha-, gamma-, delta-tocopherol in erythrocyte fragility and skeletal muscle structure should be compared to that of dl-alpha-tocopherol in future investigations.

Changes in mammary blood flow during the lactation period in goats measured by the ultrasound Doppler principle

1. Mammary blood flow was measured during the lactation period in two low- and two high-yielding dairy goats (peak milk yields approx. 1.5 and 3.6 kg/day respectively), using the ultrasound Doppler principle for determination of blood velocity in both milk veins (subcutaneous abdominal veins) of the animals, and ultrasound scanning for measurement of cross-sectional area of the veins. 2. Milk vein cross-sectional area ranged from 0.11 to 0.38 cm2 in the four goats, with a close to significant (P = 0.06) difference between the veins in the two sides of the animals. Cross-sectional area remained constant during the lactation period. Changes in mammary blood flow was therefore caused by changes in blood velocity. 3. Milk vein blood velocities ranged from 4.4 to 34.7 cm/sec independently of the time of the day, and were of the same magnitude in the two sides of the animals. Except in one goat (P = 0.1), blood velocity decreased significantly (P less than 0.01) with progressing lactation, during which period also milk yield was declining. 4. In the two low-yielding goats, a positive linear relationship (R2 = 0.20) was found between milk yield and milk vein blood velocity, whereas a diminishing exponential relationship (R2 = 0.97) was found in the two high-yielding goats. At a given milk vein blood velocity, high-yielding goats obtained a higher milk yield and also responded to changes in blood velocity (up to approx. 15 cm/sec) with greater increases in milk yield than low-yielding goats.(ABSTRACT TRUNCATED AT 250 WORDS)

A double-blind study comparing oxcarbazepine and carbamazepine in patients with newly diagnosed, previously untreated epilepsy

Two hundred and thirty-five patients suffering from newly diagnosed epilepsy were randomly allocated to treatment with either oxcarbazepine or carbamazepine in a double-blind multi-centre study. After a titration phase (between 4 and 8 weeks), the optimal individual dose of trial medication was determined and treatment with that dose was continued for another 48 weeks. The criteria for assessment were: efficacy--seizure frequency, EEG tracings, global evaluation; tolerability--side effects observed by the patient or the investigator, laboratory tests; other assessments--blood pressure and heart rate, carbamazepine and 10,11-dihydro-10-hydroxycarbamazepine trough serum levels. The results of the study showed the following: no significant difference in seizure frequency between oxcarbazepine and carbamazepine; no correlation between the therapeutic effect and the EEG findings in either treatment group; oxcarbazepine caused significantly fewer (P = 0.04) 'severe' side effects than carbamazepine; global evaluation of tolerability demonstrated a trend towards the better tolerability of oxcarbazepine; no correlation was observed between either efficacy or tolerability and the actual serum trough levels of antiepileptic drugs; clinically relevant abnormal laboratory test findings were observed in 2 patients, both on carbamazepine. The authors consider oxcarbazepine to be a valuable alternative to carbamazepine, particularly in patients who develop side effects which prevent optimal seizure control.

Organic brain syndrome treated with oxiracetam. A double-blind randomized controlled trial

In a 12-week double-blind study, oxiracetam (CGP 21690 E), a new nootropic drug, at a dose of 2.4 mg per day, was compared to placebo in the treatment of 106 middle-aged patients suffering from mild to moderate organic brain syndrome due to prolonged exposure to organic solvents. At the beginning of the study and after 12 weeks treatment, the patients underwent a battery of neuropsychological tests to determine their mental and memory functioning. A symptom questionnaire consisting of 21 items was rated pre-treatment, and improvement or worsening of any of the symptoms recorded monthly. At the end of the study a global evaluation was performed by the patients themselves, their relatives, the psychologist and the doctor. The code was not broken until the final writing of this paper. No statistically significant differences were observed between the treatment groups in any of the above-mentioned evaluations; neither were any differences in the neuropsychological tests performance observed. Thus, oxiracetam seems to have no effect in the treatment of organic brain syndrome.

Concentration-dependent effects of potassium dichromate on the cell cycle

Hexavalent chromium is found to be a strong mutagen, and it also is a potential carcinogen in man. DNA flow cytometry, growth measurements, and determinations of mitotic index show that 1-2 microM K2Cr2O7 produces a prolongation of the G2 phase of the cell cycle in NHIK 3025 cells. By increasing the chromate concentrations (greater than 2 microM K2Cr2O7) the cells are also arrested in G2 phase. We have found, using synchronized cells and measuring cell cycle time, that the most chromate-sensitive part of the cell cycle is S phase. This phase is also somewhat prolonged, and the cells became arrested in early S phase at high toxic K2Cr2O7 concentrations (8 microM). Our results thus indicate that K2Cr2O7 has an effect within S phase--maybe on DNA/RNA synthesis--and also interferes with processes necessary for progression through the G2 phase.

Response of bovine alveolar macrophages in vitro to welding fume particles

Alveolar macrophages (AM) from bovine lungs were exposed in culture to manual metal are (MMA) welding fume particles, chromium (Cr), UICC chrysotile A or anatase for 17-20 hr. All the welding particle samples were more cytotoxic to AM than to anatase. Particles from the welding of mild steel with a rutile-coated electrode were less cytotoxic than those produced with a basic-coated electrode. Particles from the welding of stainless steel were slightly more cytotoxic, and much of this activity was probably due to CrVI. Selective release of N-acetyl-beta-glucosaminidase (beta-NAG) was only detected after exposure of AM to chrysotile. Supplementation of the incubation medium with 10% serum increased the viability of all exposed AM cultures, an effect not produced by serum albumin alone. Incubation of particle samples with dipalmitoyl phosphatidylcholine (DPPC) prior to addition to AM reduced the cytotoxicity of the "rutile" welding particles and of chrysotile.

Hexavalent chromium and ascorbic acid interaction on proliferation of the human cell line NHIK3025

When cells from the human cell line NHIK3025 were cultured for 4 days, with hexavalent chromium (K2Cr2O7) at a concentration of 8 . 10(-7)M, the relative cell number was reduced to 38%. This effect of hexavalent chromium was abolished if ascorbic acid and chromate were added simultaneously to the incubation medium, but not if ascorbic acid was added 24 h prior to chromate addition. Dehydroascorbic acid was not able to reduce the effect of K2Cr2O7 either when added simultaneously or when added 24 h prior to chromate exposure. Therefore, the cells could only be protected against the toxic effect of hexavalent chromium when ascorbic acid was added at the same time as K2Cr2O7.

Effects of potassium dichromate on the cell cycle of an established human cell line (NHIK 3025)

The effect of K2Cr2O7 exposure on the cell cycle phases of the human cell line NHIK 3025 has been studied. Inhibition of cell proliferation was found to depend on the concentration and length of exposure. An effect on cell proliferation was observed 6-9 h after addition of K2Cr2O7, whereas cell death was not observed until 3-4 days later. The cells were most sensitive in G2 phase. After exposure to 8 mumol/l K2Cr2O7 the greatest prolongation of the cell cycle was in G2 + M phase, but an increase of S phase was also observed. No prolongation of G1 phase could be measured. Our results thus indicate that K2Cr2O7 delays progression through the cell cycle.

Response of a human tumour cell line to chronic potassium dichromate exposure

Cultures of the human cell line NHIK 3025 were exposed over an 18-month period to 0.5 mumol/1 potassium dichromate (K2Cr2O7) containing 1 mumol/1 hexavalent chromium. The chronically exposed cells increased their tolerance to K2Cr2O7 in comparison to control populations. The doubling time of the chronically exposed cell populations increased even in the absence of K2Cr2O7, but they did not change their morphology (light level), nor contain as many giant cells as newly exposed control populations. Cells returned to control medium for 6 months after 12-months exposure to K2Cr2O7 showed a gradual but incomplete reversal of these effects. The results are compared with those obtained from cells of non-tumour origin.