Generation of hydroxyeicosatetraenoic acids by human inflammatory cells: analysis by thermospray liquid chromatography-mass spectrometry

Arachidonic acid was converted to a series of hydroxyeicosatetraenoic acids (HETEs) by mixed human inflammatory cells following stimulation with the calcium ionophore A23187. HETEs were purified by a simple one-step extraction procedure followed by HPLC. The HPLC was coupled to a Finnigan quadrupole mass spectrometer using the now commercially available thermospray liquid chromatography-mass spectrometry interface. The HPLC eluant was monitored 'on line' by the mass spectrometer. Soft ionisation occurs, generating intense molecular ion species in the negative ion mode (M - H-:m/z 319) for each of the isomeric HETEs. The (M + H+ - H2O) ion at m/z 303 is the major species in the positive ion spectra of HETEs. Mass spectra were obtained on-line post-HPLC for HETEs formed by the human cells, and the HPLC-MS profile compared with that obtained from standards; species corresponding to the 11-, 9- and 5-HETEs were observed.     

Autonomic nervous system regulation of epicardial coronary vein systolic and diastolic blood velocity as measured by a laser Doppler velocimeter

The velocity of blood in a major epicardial coronary vein accompanying the left anterior descending coronary artery of dogs was measured by means of a 140-micron fiber optic probe connected to a laser Doppler velocimeter. Right atrial pressure, left ventricular intramyocardial and cavity pressures, aortic pressure, as well as peripheral and central coronary venous pressures were compared with the velocity of blood measured in the epicardial coronary vein midway between the sites of the catheters measuring proximal and distal coronary vein pressures. During control conditions, coronary vein velocity was 14-18 cm/s during systole and 1.0-2.1 cm/s during diastole. Right stellate ganglion stimulation, norepinephrine or isoproterenol increased diastolic coronary vein velocity significantly, whereas left stellate ganglion stimulation did not. Average peak systolic velocity was not affected by these interventions. During these positive inotropic interventions, the peak coronary vein velocity usually occurred later in the cardiac cycle than during control conditions. Positive inotropic interventions appeared to decrease coronary vein velocity during systole and increase it during diastole. Left vagosympathetic trunk stimulation decreased diastolic but not systolic coronary vein velocity and usually caused peak coronary vein velocity to occur earlier in the cardiac cycle than during control states. Changes induced by vagosympathetic trunk stimulation usually occurred within one cardiac cycle. It is concluded that coronary vein blood velocity can be influenced by the autonomic nervous system.     

Effects of extremely low frequency (ELF) electric fields on cell growth and DNA repair in human skin fibroblasts

A number of physical and chemical agents in the environment have been studied for their ability to induce or alter DNA repair mechanisms in human cells. We have investigated the effects of 60 Hz, 1000 V/cm electric fields on DNA repair in normal human fibroblasts in vitro. An examination was done on the ability of electric fields suspected to cause damage which could be repaired by thymine dimer excision and measurable by the bromodeoxyuridine photolysis assay. The thymine dimer assay with enzyme-sensitive site analysis was used to measure the cells' capacity for removing ultraviolet light (u.v.)-induced pyrimidine dimers; during exposure to electric field 24 hr before u.v. irradiation; 24 hr after u.v. irradiation; and up to 48 hr continuously after u.v. irradiation. Cell growth and cell survival following electric field exposure were also studied. Within the limits of these experiments, it was found that exposure to such electric fields did not alter cell growth or survival, and no DNA repair or alteration in DNA excision repair capacity was observed as compared with unexposed control cultures.     

The effect of salts in fermenting mashes on the microbiological assay ofl-lysine

During a study of the effects of high concentrations of NaCl, NaNO₃ and KC1 on the production of lysine bySaccharomyces cerevisiae during the fermentation of glucose (Richmond 1980) it was learned that amounts of salt greater than 0.6 M in the microbiological assay sample could change the apparent concentration of lysine in the sample. This could be corrected by adding to the lysine assay broth sufficient salt to match the concentration in the sample tube and then developing a revised standard curve. The additional salt, in turn, required that the microbiological assay time be lengthened.     

Ultrastructure of the frontal organ in Convoluta and Macrostomum spp.: significance for models of the turbellarian archetype

Present models of turbellarian evolution depict the organism with a frontal organ — a complex of glands whose necks emerge at the anterior tip of the body — and therefore imply that this organ is homologous throughout the Turbellaria. However, comparisons of representatives of the Acoela and Macrostomida, two putatively primitive orders of the Turbellaria, show that frontal organs in these two are not similar in ultrastructure or histochemistry. The acoel Convoluta pulchra had a prominent cluster of frontal mucous glands whose necks emerged together in a frontal pore at the exact apical pole of the organism, and an array of smaller glands of at least five other types opened at the anterior end, separately from and ventral to this pore. The frontal organs (Stirndrüsen) of two species of Macrostomum on the other hand, comprised an array of discretely emerging necks of at least two gland types including one with rhabdiform (rhammite) and one with globular mucous secretion granules neither of which emerge at the apical pole. In neither species did the organ appear to be sensory. Our findings indicate a low probability of homology between the frontal glands of the Acoela and Macrostomida.     

Is the Turbellaria polyphyletic?

Within the last two decades, syntheses of both light-microscopic and ultrastructural characters have shown that there are three well-defined monophyletic groups within the Platyhelminthes: 1) the Catenulidale, 2) the Nemertodermatida-Acoela, and 3) the Haplopharyngida-Macrostomida-Polycladida-Neoophora (+ parasitic platyhelminth classes). However, the relationships among these three groups are problematic. The possible apomorphies that would unite them are either not true homologues (i.e. frontal organ), are mutually conflicting (i.e. 9+1 axoneme in spermatozoa vs. biflagellate spermatozoa, epidermal ciliary rootlet structure, and protonephridia), or are unrooted with any outgroup and hence untestable or uncertain as apomorphies (protonephridia, mode of epidermal replacement, absence of accessory centrioles on cilia). The chief obstacle to deciphering the relationships of these groups is the lack of information on them; presently available information is insufficient to test potential synapomorphies and insufficient also to allow agreement upon a narrowly defined outgroup for the Turbellaria.A view consistent with the present evidence (and admittedly an unsatisfactory view) is to regard the Turbellaria (and hence the Platyhelminthes) as polyphyletic, consisting of three separate and unrelatable groups.     

Is the large-male mating advantege in anurans an epiphenomenon?

Summary This study examines the idea that variation in forelimb length among male anurans influences reproductive success, and does so independently of body size. Analyses of covariance and multivariate analyses of morphological data for five species of explosives breeders are used to test the prediction that for species in which male-male displacements contribute to variation in male reproductive success, amplectant males have longer forelimbs than do non-amplectant males at any body length. The findings for four of five species are in agreement with expectation. The results lend support to the suggestion that for explosive-breeding anurans, the large-male mating advantage may not be a consequence of large body size per se, but rather is due to the fact that large males have longer forelimbs with which to grasp females securely during amplexus and thus resist displacements by competing males.     

Amino Acid Analysis Demonstrates that Increased Plasma Free Tryptophan Causes the Increase of Brain Tryptophan During Exercise in the Rat

Rats were trained to run on a horizontal treadmill for 2 h at 20 m/min. This activity considerably increased plasma free tryptophan (TRP) (+70%) but did not alter plasma total TRP levels and had little or no effect on plasma concentrations of the other large neutral amino acids (LNAAs) that compete with TRP for entry into the brain. Brain TRP levels increased by 80%. The only other brain LNAA to be affected by exercise was threonine, which rose moderately. The results indicate that increased plasma free TRP was specifically responsible for the increase of brain TRP after 2 h of exercise. Brain lysine was also increased whereas glycine, alanine, and gamma-aminobutyric acid were decreased. The differences between the present findings and those previously obtained following 2 h immobilization stress are discussed.     

Treatment of dialysis membranes for simultaneous dialysis and concentration

Dialysis membranes used for simultaneous dialysis-concentration required pretreatment to remove uv-absorbing compounds leached from the membranes and to reduce the absorption of protein to the membranes. This was accomplished with sodium carbonate and ethanol or with "sulfur-removal solutions." Protein determinations were made with a micro-Bradford protein reaction and with uv absorbance at 280 nm. Soluble membrane components contributed to aberrant uv spectra and altered the ratio of 280/260-nm absorbance. Simultaneous dialysis and concentration in the micro protein dialyzer-concentrator apparatus, combining aspects of thin-layer dialysis and ultrafiltration, resulted in rapid removal of salts from the protein solutions. Prior treatment of membranes reduced uncertainties in retentate recoveries, eliminated uv-absorbing components of membranes, and improved recoveries of protein.     

Adaptation, Readaptation and Synthesis of Hydrogenases in Scenedesmus obliquus

Scenedesmus cells reach full hydrogen activity after 2.5 h ofanaerobic adaptation. Exposure to oxygen inactivates the hydrogenaseimmediately. Readaptation occurs with the same kinetics as primaryadaptation. The fast activation and reactivation as well asthe insensibility to cycloheximide suggest that hydrogenase,inactive or activated, is present in the chloroplast all thetime. The activation and even more the readaptation are sensitiveto chloramphenicol. Thus, we propose that hydrogenase itselfor an activating protein in the chloroplast have a rather fastturnover. ¹ Present address: Pharathiar University, Dept. of Botany, Coimbatore,India.