Hemorheologic findings in patients with ischemic heart disease

The paper deals with the rheological properties of the blood of 38 male patients affected by ischaemic heart diseases (age: 40-75 years) and 19 healthy test persons of comparable age. The following haemorheological properties were measured. 1. Relative plasma viscosity 2. Erythrocyte aggregation 3. Erythrocyte deformability 4. Thrombocyte aggregation and 5. Whole blood viscosity. For the purpose of representing and assessing the results of measurement obtained a division was made into different groups according to the appearances of ischaemic heart disease (chronic ischaemic heart disease, unstable angina pectoris, acute heart infarct) and risk factors (smoking, diabetes mellitus, blood high pressure and hyperlipidaemia). The methods 1-3 proved to be especially suitable for representing gradual differences in the examined rheological parameters. The results obtained are discussed and evaluated.     

Reproductive interactions between two Australian reptile tick species

In South Australia the two tick species Amblyomma limbatum and Aponomma hydrosauri share the same common reptile host species, but have allopatric distributions which abut along a narrow parapatric boundary. Reproductive interference is a mechanism that has previously been suggested could contribute to maintaining the boundary. Populations of each species were established in pens within the range of Aponomma hydrosauri. Pens held either each species alone, or the two species together. The performance of females in those pens was monitored over 28 months. There was no indication that the proportion of attached females which mated and engorged was reduced by the presence of heterospecifics. There was no indication that the time taken to mate, engorge and detach was any longer in the presence of heterospecifics. The experiment did not support the hypothesis that reproductive interference contributes to maintaining the parapatric boundary. However, Amblyomma limbatum in the pens had a shorter season of reproductive activity, and achieved much smaller numbers of reproductive females. This may inhibit successful colonization of cooler habitats to the south of its distribution.     

Effects of HCO3/CO2 on the cytochrome redox potential and metabolic responses of isolated rat cerebral cortex.

The importance of HCO₃^?/CO₂ to the maintenance of stable metabolic conditions in rat cerebral cortex slices has been investigated. Replacement of bicarbonate buffered media with glycylglycine or phosphate buffered salines resulted in an increased lability of the cytochrome redox potential of brain slices as measured by dual wavelength spectroscopy. Depletion of reduced cytochrome in the electron transport chain was associated with changes in the metabolic responses of tissues to electrical stimulation or elevated concentrations of potassium. This appears primarily as a loss of the late reductive responses of the tissue nicotinamide adenine dinucleotides NAD(P)H to these stimuli and decreased lactic acid output of the tissues. The effects could be largely reversed in a combined glycylglycine and HCO₃^?/CO₂ buffered media. It is suggested that although the reduction of NAD(P) in response to stimulation may be substantially located in the cytosol, it is also modulated by the mitochondrial redox potential. It is suggested that the lability of the redox potential in the absence of HCO₃^?/CO₂ may be related to depletion of TCA cycle intermediates normally replaced by CO₂ fixation.     

Occurrence of 13(S)-Hydroxyoctadecadienoic Acid in Biological Samples

The oxygenated metabolite of linoleic acid, 13(S)-hydroxyoctadecadienoic acid has recently been shown to play a role in cellular regulation. To detect this molecule in biological systems, we recently developed a specific polyclonal antibody. Using this antibody, we report the presence of 13(S)-hydroxyoctadecadienoic acid in human urine, cell culture media, and untreated goat serum for the first time by a specific, sensitive, and rapid enzyme immunoassay. Furthermore, the enzyme linked immunosorbent assay data are verified by gas chromatography/mass spectrometry analysis of the same samples.     

Formation of mutagens following chlorination of humic acid. A model for mutagen formation during drinking water treatment

Aqueous chlorination of humic acids results in the formation of compounds with direct-acting mutagenic activity in the Ames/Salmonella plate assay for tester strains TA98, TA100, TA1535, TA1537 and TA1538. The addition of a rat-liver microsomal fraction (S9) plus cofactors causes a substantial decrease of activity, the extent of which is tester strain dependent. The non-chlorinated humic acids are not mutagenic either in the presence or absence of S9. Formation of mutagenic activity and of total organic halogen (TOX) is linearly related to humic concentration in the range of 0.2-1.6 mg/ml total organic carbon (TOC), and to chlorine concentration in the range of 0.1-1.0 chlorine equivalents per mole of carbon. The mutagenic activity is due predominantly to non-volatile compounds. Mutagenic activity is also detectable, after sample concentration by lyophilization, upon chlorination at a humic acid level of 0.02 mg/ml TOC. The specific mutagenic activities (per mg TOX), and also the degree of chlorine incorporation into humic acid, at 0.02 mg/ml TOC are similar to those present after chlorination at 1 mg/ml TOC. Production of mutagens is greatly dependent on the chlorination pH, with a pattern of decreasing mutagenic activity with increasing pH. This order of activity can be at least partially explained by the alkali liability of the compounds. Chlorination of commercial humic acids is proposed as a model for examination of mutagen formation during water chlorination.     

Effects of anisomycin on brain protein synthesis and passive avoidance learning in newborn chicks

The effects of anisomycin (ANM) on newborn chicks have been studied with respect to brain protein synthesis, growth, EEG, toxicity, and several passive avoidance learning tasks. It was found that intracerebral ANM (80 nmol) gave a maximum inhibition of brain protein synthesis of 30%, while a combination of subcutaneous (10 μmol; 53 mg/kg) plus intracerebral (80 nmol; 21 μg) ANM, inhibited by 91% in the first 2 hr and by 75% in the subsequent 2 hr period. Cycloheximide (CXM) also in combined injections at the same doses as ANM, inhibited by 97% in the 4 hr that followed injection. However, all the CXM-injected chicks were dead by 18 hr, while the lethality of ANM did not differ from that of saline. ANM also did not affect EEG measured at 1, 3, 5, or 24 hr following the subcutaneous plus intracerebral injections, nor did ANM affect body or brain growth curves or brain protein accretion. In the learning experiments, animals were initially trained to peck at water-coated metal spheres (type A learning) or at water-imbibed birdseed (types B and C learning) in less than 1 sec, and were exposed to the same lures treated with the aversant methylanthranilate (MeA) one day later on one occasion (types A and B learning) or exposed twice (type C learning) and tested for learning retention one day later. Learning criterion was set as failure to peck at the lure during the first 20 sec of presentation. If ANM was injected 1 hr prior to MeA exposure, large and highly significant memory deficits were found during the retention test, as compared with saline injected controls. No effect of ANM was seen, however, if it was injected one day after learning, indicating that it did not interfere with retrieval mechanisms. ANM also decreased the external manifestations of fear or displeasure that chicks express during retention testing. Such manifestations have a high correlation with pecking suppression (r = 0.88, P < 0.001).