Modulation of vincristine sensitivity of human kidney tumor cells by pharmacological agents interfering with intracellular signals. No apparent relationship to changes in cytoplasmic Ca2+ or pH

The effect of substances proposed to modulate intracellular signal systems on growth and sensitivity to vincristine in the human kidney tumor cell line ACHN was investigated and related to changes in cytoplasmic free Ca2+ concentration ([Ca2+]i) and cytoplasmic pH (pHi). Presence during culture of the protein kinase C (PKC) activator 12-O-tetradecanoyl phorbol 13-acetate (TPA) had no effect on cell growth but significantly increased the EC50 concentration for vincristine inhibited cell growth. There was no indication for endogenous PKC activity being responsible for basal vincristine insensitivity since it was not affected by the PKC inhibitor H-7. The Ca2+ ionophore ionomycin tended to increase cell growth and induced vincristine resistance, whereas the calmodulin inhibitor W-7 had opposite effects. Presence during culture of the adenylate cyclase activator forskolin did not affect basal cell growth but dose-dependently made the cells more sensitive to vincristine. The modulators of vincristine sensitivity had no immediate effect on pHi, whereas after 3 days of incubation ionomycin and forskolin tended to increase pHi. Ionomycin and forskolin induced an immediate increase in [Ca2+]i which remained after 3 days only for ionomycin, whereas TPA decreased [Ca2+]i, a change which tended to remain after 3 days of incubation. It is concluded that perturbation of the intracellular signal system may affect both cell growth and cytotoxic drug sensitivity. However, there is no apparent relationship between immediate or late changes in [Ca2+]i and pHi and vincristine sensitivity.     

Enzymatic catalysis in microemulsions: enzyme reuse and product recovery

A technique for enzyme reuse and product recovery from enzymatic catalysis in microemulsions is demonstrated. The enzymatic reaction is performed in a homogeneous isotropic microemulsion; AOT (sodium bis-(2-ethyl- hexyl)sulfosuccinate)/isooctane/buffer or C(12)E(5)(penta ethylene glycol dodecyl ether)/heptane/buffer. By small temperature changes the systems are shifted to two phase regions, where an oil-rich phase, containing the product, coexists with a water-rich phase containing surfactant and enzyme. The oil-rich phase may be replaced by an oil solution containing new substrate. Thus, the reaction may be continued and the enzyme reused. This procedure was repeated nine times in the present study. Data on phase behavior in presence and in absence of protein, partitioning of the components and a radioactive-labelled protein between the phases, and the repeated use of horse liver alcohol dehydrogenase (HLADH) in the microemulsions are presented.     

Detection of microbial contamination in fermentation processes: mass spectrometric determination of gram-negative bacteria in Leuconostoc mesenteroides cultures

Gas chromatography/mass spectrometry was used to detect the presence of Enterobacter cloacae in cultures of Leuconostoc mesenteroides, an organism used in an industrial process for production of dextrane. The penta-fluorobenzoyl-methyl ester derivative of 3-hydroxy-myristic acid, a characteristic compound of gram-negative bacteria, was used as the analyte. By using gas chromatography/mass spectrometry with selected ion monitoring, E. cloacae was determined over the range of 1 ppm to 1% in cultures of L. mesenteroides. The proposed analytical approach represents a useful alternative to conventional methods for determining contaminating organisms in industrial fermentation processes.     

Human fibroblasts show expression of the leukotriene-A4-hydrolase gene, which is increased after simian-virus-40 transformation

Human fibroblasts in cell culture converted the epoxide intermediate leukotriene A4 into the potent chemotaxin leukotriene B4. The identity of leukotriene B4 was ascertained by its mobility in reverse-phase high performance liquid chromatography, ultraviolet spectroscopy and gas chromatography/mass spectrometry. The presence of the enzyme responsible for the conversion (i.e. leukotriene A4 hydrolase), as well as the corresponding mRNA, were demonstrated by Western and Northern blot analyses. Leukotriene-A4-hydrolase enzyme activity, protein and mRNA were all enhanced (approximately threefold) in human fibroblasts that had been transformed by simian virus 40.     

Muscle hypertrophy in bodybuilders

Muscle biopsy samples were obtained from m. vastus lateralis and m. deltoideus of three high caliber bodybuilders. Tissue specimens were analysed with respect to relative distribution of fast twitch (FT) and slow twitch (ST) fiber types and different indices of fiber area. In comparison to a reference group of competitive power/weight-lifters the following tendencies were observed: the percentage of FT fibers was less, mean fiber area was smaller and selective FT fiber hypertrophy was not evident. Values for fiber type composition and fiber size were more similar to values reported for physical education students and non-strength trained individuals. The results suggest that weight training induced muscle hypertrophy may be regulated by different mechanisms depending upon the volume and intensity of exercise.     

Parturient Paresis in the Cow

Serum ionized calcium concentrations (CaF) were determined in 87 Swedish red-and-white cows and 10 Swedish Friesian cows with clinical signs of parturient paresis. All cows were in the week prior to or after parturition. A classification of the severity of hypocalcemia in terms of serum ionized calcium was devised. Eight cows had normal serum ionized calcium concentrations (Cap 1.06–1.26 mmol/1); 15 had slight (CaF 0.80–1.05 mmol/1); 43 a moderate (CaF 0.50–0.79 mmol/1), and 31 asevere (CaF < 0.50 mmol/1) hypocalcemia. All cows were given 8 or 8.3 g of calcium intravenously. Of 8 normocalcemic cows 7 (87.5 %) reached a maximum posttreatment serum ionized calcium concentration > 1.80 mmol/1 (severe hypercalcemia). This was also found in 13 of 15 (86.7 %) slightly hypocalcemic cows and in 31 of 43 (72.1 %) moderately hypocalcemic cows. In the severe hypocalcemia group 14 of 31 (45.2 %) had maximum posttreatment Cap > 1.80 mmol/1). These findings emphazise the need of a rapid pretreatment evaluation of the degree of hypocalcemia. The present study also underlined the difficulty in predicting serum ionized calcium from serum total calcium concentrations.     

Morphological studies of Asian rice and its related wild species and the recognition of a new Australian taxon

In order to clarify the taxonomy and the interrelationships among Asiatic cultivated rice, Oryza sativa , and its related wild species ( O. rufipogon, O. nivara and O . barthii ), 41 morphological characters were examined. Numerical taxonomic methods were used to analyse the data and to illustrate species relationships.
Distinctive differences among the materials studied suggest the retention of O. rufipogoon, O. nivara and O . sativa as three distinct species. The origin of O. sativa from O. nivara through domestication is discussed. An annual wild taxon from Australia, which had been classified as a form of O. nivara , is shown to be distinct from typical O. nivnra and is raised to specific rank. This species has been named O. meridionalis Ng.     

Analysis of glucose catabolites by using head-space gas chromatography for differentiation of some Gram-negative species

Volatile products from the degradation of glucose by a total of 66 strains ofEnterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Proteus vulgaris, andPseudomonas aeruginosa were analyzed by head-space gas chromatography. The bacteria were incubated for 1 h in a glucose-containing buffer solution before being analyzed by gas chromatography, using manual, semiautomatic, and automatic head-space injection. From the chromatographic patterns obtained, all strains could be differentiated as to species, with the exception of two strains ofProteus mirabilis, which gave chromatograms similar to those produced byProteus vulgaris. The gas chromatographic head-space technique developed provides a rapid and easily performed means for identification of bacteria, particularly when using an automatic injection unit, as exemplified in this study on some of the Gram-negative species commonly encountered in urinary tract infections.     

Prostaglandins and thromboxanes in amniotic fluid during rivanol-induced abortion and labour

Abortion or delivery were induced by extra-amniotic instillation of Rivanol during the second trimester in twelve patients and during the third trimester in two patients with fetal death and one patient with fetal acrania. Serial sampling of amniotic fluid was performed through a transabdominal catheter and the levels of free arachidonic acid (AA), prostaglandin F₂α (PGF₂α), prostaglandin E₂ (PGE₂), 6-keto-prostaglandin F₁α (6-keto-PGF₁α) and thromboxane B₂ (TXB₂) were determined. The levels of AA, PGF₂α, PGE₂, 6-keto-PGF₁α and TXB₂ in amniotic fluid increased significantly during induction with the exception of AA in fetal death which was high and remained constant during induction. Furthermore, PGF₂α, 6-keto-PGF₁α and TXB₂ were all significantly correlated to AA.These observations suggested that free AA is released during Rivanol-induction of abortion and labour giving an increased synthesis of PGF₂α, PGE₂ prostacyclin and thromboxane A₂ in the fetal membranes and the decidua but not in the fetus. This increase might be relevant for the initiation and progress of abortion and labour in these patients.     

Vitamin analysis with use of a yeast electrode

A vitamin B₁ (thiamin)-sensitive electrode has been devised by combining an oxygen electrode with a yeast-containing membrane. The assembly was used for assaying thiamin at concentrations down to 10^?11 gl^?1. The analytical procedure developed should allow the measurement of 10–20 samples per hour. The performance of the yeast electrode was improved when alginate membranes reinforced with a nylon network were used. An apparatus for preparing such membranes is described together with a magnetic membrane holder facilitating handling of membranes in combination with electrodes.