Simultaneous determination of (R)- and (S)-celiprolol in human plasma and urine: high-performance liquid chromatographic assay on a chiral stationary phase with fluorimetric detection

The quantitative enantiospecific determination of the beta 1-selective adrenergic antagonist (R,S)-celiprolol in human plasma and urine is described. It involves a two-step liquid-liquid extraction of celiprolol from biological material and separation of the underivatized enantiomers by high-performance liquid chromatography on a chiral stationary phase (cellulose tris-3,5-dimethylphenyl carbamate, coated on silica gel) with fluorimetric detection. R-(+)-Propranolol was used as an internal standard. The detection limits of 1.5 ng/ml enantiomer in plasma and 2.5 ng/ml enantiomer in urine at signal-to-noise ratios higher than 3 permit the performance of pharmacokinetic studies after therapeutic doses.

A new test for endothelial viability. The Janus green photometry technique

A new in vitro technique was developed to measure, by simple photometry, the amount of Janus green extracted with absolute alcohol from isolated corneas after vital staining. The amount of stain corresponded to the percentage of damaged endothelial cells and was a reliable parameter of endothelial viability. More rapid and easier to perform than the usual cell counting of devitalized cells, this technique can be used to study the endothelial damage induced, for example, by experimental surgery, intraocular solutions, intraocular lens material, corneas storage solutions. As an example of application, results of the endothelial status after medium-term preservation of pig corneas (n = 40) in a modified McCarey-Kaufman medium at 4 degrees C were determined. The mean +/- endothelial damage was 8.5% +/- 1.8% (mean +/- SD) after 4 days, 29.5% +/- 3.7% after 7 days, 45.5% +/- 5.5% after 10 days, 69.3% +/- 3.7% after 14 days, and 100% after 20 days of storage in McCarey-Kaufman medium.

Identification of new mitochondrial genome organizations in wheat plants regenerated from somatic tissue cultures

Plants have been regenerated from short-and long-term in vitro somatic tissue cultures made from immature embryos of the hexaploid wheat cultivar "Chinese Spring". The mitochondrial genome organization of each regenerated plantlet was studied, after one selfing, by probing Sal I-restricted total DNA with cloned Sal I fragments of wheat mitochondrial DNA derived from a segment of the genome, which displays marked structural changes in response to in vitro culture. Short-term in vitro cultures give rise to regenerated plants whose mitochondrial genome organization is either close to that of the parental cultivar or to that of embryogenic callus cultures, except for a single plant which has an organization resembling that of short-term non-embryogenic cultures. In contrast, all but one of the plants regenerated from long-term cultures exhibited a mitochondrial genome organization similar to that of long-term nonembryogenic cultures. In addition, extra labelled bands were detected in some of the regenerated plants with two of the probes used. These results emphasize the importance of the duration of the in vitro step preceding the regeneration process: the longer it is, the higher the probability is of obtaining mitochondrial DNA variability in regenerated plants. Furthermore, since increasing the duration of the in vitro stetp results in the production of regenerated plants with a mitochondrial genome organization resembling that of non-embryogenic tissue cultures, the question is thus raised as to whether regeneration from long-term cultures is suitable for use in plant breeding.

[A new in vitro test of endothelial viability. Vital staining using Janus green with spectrophotometric analysis of the color extract]

A new in vitro technique has been developed to measure by simple photometry the amount of Janus Green extracted with absolute alcohol from isolated corneas after vital staining. The amount of stain corresponds to the percentage of damaged endothelial cells and is a reliable parameter of endothelial viability. More rapid and easier to perform than the usual cell counting of devitalized cells this technique may be used to study the endothelial damage induced e.g. by experimental surgery, intraocular solutions, IOL material, cornea storage solutions.

Variations in long-term wheat somatic tissue culture

Morphological and chromosomal changes were induced among plants regenerated from wheat somatic embryogenic tissues that retain regenerative potential for a long time. An effect of in vitro culture on mitochondrial DNA was also ascertained since variations in mitochrondrial DNA were observed in embryogenic and nonembryogenic genotypes. These variations were detected on restriction patterns. The possible significance of the mtDNA variations in affecting plant fertility and regeneration ability is discussed.

[One year after Chernobyl. Cesium-137 levels in premature, newborn and nursing infants and in younger and older children of Bonn and environs]

From May to August 1987, 137Cs activity was measured in a total-body counter (4 pi counter) in 33 premature and mature newborns (group I), 40 infants and young children up to 2 4/12 years of age (group II), and 15 children between 3 and 6 8/12 years (group III), all from Bonn or its environs. The mean of measurements in group II, at 3.7 Bq/kg body-weight, was lower than that of group I (5.8 Bq) and III (9.4 Bq). Mean radiation exposure, calculated from these data, was 1.7 mrem/a for group I, 1.1 mrem/a for group II, and 2.8 mrem/a for group III. A comparison with present Cs values in adults and measurements made at the end of the 1950's and beginning of 60's showed good agreement. There were no significant differences, as regards Cs activity, between newborns or infants who had been formula-fed or breast-fed. The measured radiation exposure of the three groups is about 1% of natural radiation exposure. Thus, present-day results indicate that there will be no damage to health outside the natural scatter.

Evaluation of daunomycin toxicity on lens epithelium in vitro

Posterior capsule opacification is the major complication of extracapsular cataract extraction (ECCE). Lens epithelial cells derived from the periphery of the lens are thought to migrate posteriorly and contribute significantly to the postoperative proliferations at the posterior pole. We have evaluated the effects of the antiproliferative drug daunomycin on cultured porcine lens epithelial cell viability and proliferation. We observed that the mitotic activity of the cells is suppressed by a single short time treatment with daunomycin at a concentration as low as 2.5 mg/l. Long term effects on the reproductive capacity of the lens epithelial cells may not be as pronounced as the inhibition of other cells examined before e.g. retinal pigment epithelium and fibroblasts. Our results indicate that daunomycin may be useful for the pharmacologic prevention of postoperative proliferations in patients treated by ECCE.

Pyrroloquinoline quinone: a new redox cofactor in eukaryotic enzymes

During the past decade pyrroloquinoline quinone has been shown to be a new redox cofactor for a range of bacterial alcohol dehydrogenases. Recent studies suggest that this cofactor may also be covalently bound to the active site of the eukaryotic copper amine oxidases. In this mini-review we present the evidence in support of pyrroloquinoline quinone as a novel eukaryotic cofactor. As a result of mechanistic advances during the last three years, together with a re-examination of previously existing data, a working model for the role of pyrroloquinoline quinone in enzyme-catalyzed amine oxidation reactions can be proposed.

Endothelial alterations in AIDS with cytomegalovirus infection

We report on a patient in whom a cytomegalovirus infection occurred in connection with AIDS. Together with the alterations of the fundus typical for cytomegalovirus retinitis, reticular deposits were observed on the corneal endothelium. Specular microscopy showed occasional endothelial cells with edema, as well as small, dark, round, mobile structures (probably lymphocytes) and large, bright, spindle-shaped, immobile structures (probably macrophages) located behind the endothelium. Despite treatment with corticosteroids and acyclovir, an increase in the extent of the findings was observed. The deposits are interpreted as a reaction of the endothelium to the cytomegalovirus infection.

Aromatase activity in monolayer cell cultures of human endometrium

Monolayer cell cultures of proliferative human endometrial stromal cells were incubated with 100 nCi 3H-androstenedione or 100 nCi 3H-testosterone for 15 hours. After termination of the incubations 16% of the recovered radioactivity was identified as estrone by thin layer chromatography and subsequent recrystallization. 3H-testosterone was almost quantitatively converted to 3H-androstenedione. 3H-dihydrotestosterone remained unmetabolized. These findings indicate a highly active 17 beta-ol-dehydrogenase and a high aromatizing capacity of human endometrial cells.

Gametoclonal variation detected in the nuclear ribosomal DNA from doubled haploid lines of a spring wheat (Triticum aestivum L., cv. 'César')

The organization of the nuclear ribosomal DNA from a parental line of wheat (Triticum aestivum L., cv. 'César') and its anther-derived first cycle and second cycle doubled haploid lines has been analyzed by DNA-DNA molecular hybridization. Restricted DNA has been probed by three subclones of wheat nuclear ribosomal DNA covering the entire repeat unit. No significant difference was detected in the extent of methylation of ribosomal DNA of the doubled haploid lines with respect to the parental line. On the other hand, a variation has been found in the organization of the nontranscribed spacer region of ribosomal DNA of the first cycle doubled haploid line. This variation remains stable after a second cycle of in vitro androgenesis. However, one out of five second cycle doubled haploid lines so far tested showed an additional hybridization band present in the parental line but lacking in the first cycle doubled haploid line.

Reductive trapping of substrate to bovine plasma amine oxidase

Plasma amine oxidases catalyze the oxidative deamination of amines to aldehydes, followed by a 2e- reduction of O2 to H2O2. Pyrroloquinoline quinone (PQQ), previously believed to be restricted to prokaryotes, has recently been proposed to be the cofactor undergoing reduction in the first half-reaction of bovine plasma amine oxidase (Ameyama, M., Hayashi, U., Matsushita, K., Shinagawa, E., and Adachi, O. (1984) Agric. Biol. Chem. 48, 561-565; Lobenstein-Verbeek, C. L., Jongejan, J. A., Frank, J., and Duine, J. A. (1984) FEBS Lett. 170, 305-309). This result is unexpected, since model studies with PQQ implicate Schiff's base formation between a reactive carbonyl and substrates, whereas experiments with bovine plasma amine oxidase have failed to provide evidence for a carbonyl cofactor. We have, therefore, re-examined putative adducts between substrate and enzyme-bound cofactor, employing a combination of [14C]benzylamine and [3H]NaCNBH3. The use of the relatively weak reductant, NaCNBH3, affords Schiff's base specificity and permits the study of enzyme below pH 7.0. As we show, enzyme can only be inactivated by NaCNBH3 in the presence of substrate, leading to the incorporation of 1 mol of [14C]benzylamine/mol of enzyme subunit at complete inactivation. By contrast, we are unable to detect any labeling with [3H]NaCNBH3, analogous to an earlier study with [3H]NaCNBH4 (Suva, R. H., and Abeles, R. H. (1978) Biochemistry 17, 3538-3545). We conclude, first, that our inability to obtain adducts containing both carbon 14 and tritium rules out the reductive trapping either of amine substrate with pyridoxal phosphate or of aldehyde product with a lysyl side chain and, second, that the observed pattern of labeling is fully consistent with the presence of PQQ at the active site of bovine plasma amine oxidase.

Small tandemly repeated DNA sequences of higher plants likely originate from a tRNA gene ancestor

Several monomers (177 bp) of a tandemly arranged repetitive nuclear DNA sequence of Brassica oleracea have been cloned and sequenced. They share up to 95% homology between one another and up to 80% with other satellite DNA sequences of Cruciferae, suggesting a common ancestor. Both strands of these monomers show more than 50% homology with many tRNA genes; the best homologies have been obtained with Lys and His yeast mitochondrial tRNA genes (respectively 64% and 60%). These results suggest that small tandemly repeated DNA sequences of plants may have evolved from a tRNA gene ancestor. These tandem repeats have probably arisen via a process involving reverse transcription of polymerase III RNA intermediates, as is the case for interspersed DNA sequences of mammalians. A model is proposed to explain the formation of such small tandemly repeated DNA sequences.

[Trypan blue and alizarin red S sequential staining with subsequent fixation. A modified technic for the study of the corneal endothelium]

A sequential corneal endothelium staining technique with trypan blue (TB)--alizarin red S (ARS)--ethanol-trypan blue is described which can be performed in a few minutes. The first step permits the TB exclusion to be determined as a criterion of normal endothelial cell function. The two following steps permit intercellular staining by ARS and nuclear staining by TB. After each staining procedure, fixation can be performed by methanol or ethanol, both with full-thickness corneal preparations or endothelial flat mounts. In flat preparations, the focussing problems and optical artifacts of full-thickness mounts can be avoided. These modifications render simple sequential staining with subsequent fixation a complement and alternative to specular microscopy and to the customary complicated silver staining of corneal endothelium.

Gene conversion as a mechanism for divergence of a chloroplast tRNA gene inserted in the mitochondrial genome of Brassica oleracea

We have characterized a 1.7 kb sequence, containing a tRNA Leu2 gene shared by the ct and mt genomes of Brassica oleracea. The two sequences are completely homologous except in two short regions where two distinct gene conversion events have occurred between two sets of direct repeats leading to the insertion of 5 bp in the T loop of the mt copy of the ct gene. This is the first evidence that gene conversion represents the initial evolutionary step in inactivation of transferred ct genes in the mt genome. We also indicate that organelle DNA transfer by organelle fusion is an ongoing process which could be useful in genetic engineering.

Organelle genome stability in anther-derived doubled haploids of wheat (Triticum aestivum L., cv. 'Moisson')

Chloroplast and mitochondrial compartments of a parental line of wheat (Triticum aestivum L., cv. 'Moisson') and its anther-derived doubled haploid lines have been analyzed and compared on the basis of their DNA restriction patterns. The results obtained show that no noticeable difference can be detected between doubled haploid lines and parental line at the level of ctDNA and mtDNA organization. It may be concluded that in vitro culture by itself does not systematically generate a cytoplasmic variation in germ cells.

Follow-up study of 100 malignant pleural mesotheliomas

One hundred malignant pleural mesotheliomas have been treated in our hospital since 1955. Clinical and autopsy findings are analyzed and compared to X-ray changes. The most common symptoms were dyspnea (49%), pain (40%) and cough (36%). The main initial X-ray signs were pleural effusion (62%), pleural thickening (29%) and solitary nodules (6%). Prior to death a combination of effusion and pleural thickening was the usual finding. Histologically there were 49 biphasic, 32 mesenchymal and 18 epithelial malignant pleural mesotheliomas. At autopsy 82% of the cases had distant metastases, most of which had not been expected clinically. The median survival time was 7.3 months following the first clinical symptoms, and only 4 months after the first radiological signs.

Possible effect of the cell synchronization method on the pattern of 5-bromodeoxyuridine incorporation into early synthesized DNA

Synchronously and asynchronously growing chick embryo fibroblasts have been used to study the pattern of 5-bromodeoxyuridine (BrdU) incorporation into DNA. In the synchronous cell system, the density of unifilarly substituted DNA is about 0.010 g/ml higher during first half of S phase than during second half of S phase. The density of unifilarly substituted DNA isolated from asynchronously growing cells is similar to that of DNA synthesized during the second half of S phase of synchronously growing cells for a given concentration of analogue in culture medium. Reassociation kinetics experiments have shown the oversubstitution to occur at the level of early synthesized repeated and/or intermediate DNA sequences. It is then assumed that the oversubstitution is due to some metabolic changes caused by the synchronization procedure itself. As BrdU incorporation into early replicating DNA is known to induce alterations of the cell metabolism, the implication of this phenomenon is discussed at the level of the inhibition of transformation which takes place when chick embryo fibroblasts are infected with Rous sarcoma virus during G1 and subsequently treated with BrdU during early S phase.