Natural zeolite clinoptilolite increases the concentrations of sphingoid bases in the yeast Yarrowia lipolytica

In the present paper, we studied the effect of natural zeolite clinoptilolite on sphingolipid metabolism in the yeast Yarrowia lipolytica. We also investigated if zeolite addition had any impact on cell shape and size, as well as on the pH alterations during the culture growth. High performance liquid chromatography analysis of sphingoid bases obtained by acid hydrolysis of complex sphingolipids from Y. lipolytica showed that their concentrations markedly rose upon the zeolite addition. The largest increase among the identified molecular species of sphingoid bases was seen in C18 phytosphingosine, whose levels rose 6.2-fold and 22.3-fold after culturing cells for 24 and 36 hours respectively in the presence of finely ground zeolite. pH measurements of the culture medium showed a similarity between pH profiles of control and zeolite-supplemented cells, suggesting that ion-exchange capacity was not probably responsible for the observed change in sphingolipid metabolism. Scanning electron microscopy revealed that zeolite affected cell size and shape. Y. lipolytica cells grown in the absence of zeolite were oval-shaped with an average cell size of 0.7-2.7 microns, whereas when cultured with zeolite, they were round-shaped and larger, having an average cell size of 1.3-2.9 microns.     

Thrombotic thrombocytopenic purpura--possibilities of treatment and results

Results of treatment of 13 patients fulfilling the criteria for TTP are presented. Thrombocytopenia was present in all patients (100%). Eleven of 13 patients (84.6%) had conciousness disorder, and seven of 13 patients (53.8%) had renal impairment. Immunosuppressive therapy with plasmapheresis and replacement of removed volume with fresh frozen plasma in a dosage of 25 ml/kg body weight resulted in statistically significant increase of platelet count (p = 0.0033), and significant improvement of consciousness as defined by increased Glasgow Coma Score (GCS) (p = 0.0524). In two patients, renal function recovered and, in one patient, hemodialysis was no longer needed. This improvement in a small patient group has no statistical significance.     

Einfluß der Hibernation auf die Vermehrung und Ausbreitung von Virus Aujeszky

Zusammenfassung Die artifizielle Hibernation hemmt und verzögert die Vermehrung und die Ausbreitung von Virus Aujeszky im ZNS. peripher infizierter Kaninchen erheblich. Hierdurch findet die frühere Beobachtung 1, wonach die Dauer der Inkubationsperiode und des Krankheitsverlaufes des M. Aujeszky bei Kaninchen beträchtlich verlängert ist, eine hinreichende Erklärung.     

Type of isoniazid (INH) acetylation determined in tuberculosis patients treated at the Institute of Tuberculosis and Lung Diseases in Warsaw during the years 1990-1997

The researched has dealt with the type of acetylation in 237 TB patients treated with standard course of chemotherapy with a dose of 300 mg of INH in period 1990-1997 in National Research Institute of Tuberculosis and Lung Disease in Warsaw Blood samples were taken before (time 0) and 1, 3, 6 and 24 h after drug administration. Plasma concentrations of isoniazid were determined with biological methods. Two indies of acetylation rate--I3 and C6 have been used to determine an acetylation type. Majority of the treated patients (68.8%) have shown fast type of INH acetylation. After similar dose of isoniazid different profile of absorption and excretion of the drug and significant differences (p < 0.01) in INH concentrations, acetylation rate and bioavailability between 163 fast and 74 slow acetylators have been observed. In plasma of 38.6% fast acetylators drug concentration 3 h after ingestion of a dose did not achieve the concentration of 1 mcg/ml. In plasma of 29.7% slow acetylators, concentrations of INH 6 h after ingestion were higher than 2 mcg/ml.     

Biochemical changes in the sublingual and submandibular glands after interruption of chorda tympani

The left chorda tympani nerve was interrupted through meatus acusticus externus in ten dogs. In total, 40 dog salivary glands (20 submandibular and 20 sublingual) innervated via chorda tympani were examined. Twenty glands (10 submandibular and 10 sublingual) on the left side were deprived of parasympathetic innervation by chordectomy, whereas contraleteral glands, on the right side, served as controls. Biochemical analysis showed that the interruption of chorda tympani did not cause any significant changes in the concentrations of eight enzymes investigated, i.e. lactate dehydrogenase, alkaline phosphatase, acid phosphatase, amylase, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase and creatine kinase. There were no significant changes in the concentrations of most important extracellular ions (sodium, potassium, chloride and phosphorus) in the right glands, but the loss of parasympathetic innervation in the left glands was found to cause a statistically significant decrease in the concentration of potassium as intracellular cation and of phosphorus as extracellular anion.     

Progressive loss of lambda prophage recombinogenicity in UV-irradiated Escherichia coli: the role of RecBCD enzyme

RecBCD enzyme is involved in the radiation-induced process known as prophage inactivation. The process leads to the inability of lambda prophage to excise itself from the Escherichia coli chromosome via site-specific recombination. In this work we sought to further characterize the role of RecBCD enzyme in this process. In addition, we examined the ability of irradiated prophage to recombine with the infecting homologous phage. We used several E. coli mutants differentially altered in RecBCD's activities. The results showed that in the mutants carrying either recB2109 or recD1903, which do not exhibit significant nuclease activities, the prophage progressively loses its capacity for both site-specific and general recombination. In the recB268 null mutant, however, prophage recombinogenicity remained fully preserved. We also showed that the prophage unable to recombine retained its ability to complement the mutant infecting phage and that the recombination frequencies in phage x phage crosses were not affected by postirradiation incubation. Our results suggest that the helicase activity of RecBCD is responsible for the progressive loss of prophage recombinogenicity. This loss is most probably a consequence of the unsuccessful RecBCD-dependent recombinational repair of double-stranded breaks in the cell chromosome, during which some structures unsuitable for further recombination reactions may be produced.     

Dithiothreitol prevents age-associated decrease in oocyte/conceptus viability in vitro

The present study was designed to ascertain whether the negative effects on reproductive potential of post-ovulatory ageing in vitro of oocytes can be prevented by antioxidant therapy. Mouse metaphase II (MII) oocytes were aged in vitro for 12 h prior to insemination in the presence of varying concentrations of L-ascorbic acid, 6-methoxy- 2,5,7,8-tetramethylchromane-2-carboxylic acid (Trolox), L-cystine dihydrochloride, ethylenediaminetetraacetic acid (EDTA), beta- mercaptoethanol and DL-dithiothreitol (DTT). In-vitro ageing of oocytes was associated with lower fertilization rate, higher proportion of concepti exhibiting cellular fragmentation at 24 h post-insemination and lower percentage of concepti reaching the blastocyst stage. Ascorbic acid, Trolox and EDTA had no effect on cellular fragmentation or potential of oocytes for development. However, the probability of an oocyte reaching the blastocyst stage was decreased (P < or = or = 0.05) in oocytes incubated in the presence of L-cystine (50 and 500 microM) and beta-mercaptoethanol (5, 50 and 500 microM) when compared to control aged oocytes. Age-associated cellular fragmentation at 24 h post-insemination was partially prevented (P < or = 0.05) by incubating oocytes in the presence of beta-mercaptoethanol (500 microM). DTT (50 and 500 microM) increased (P < or = 0.05) fertilization rate and number of cells at 81 h post-insemination to levels similar to those exhibited by control oocytes. Furthermore, both age-associated fragmentation at 24 h post-insemination (P < or = 0.05) and decreased potential of oocytes for development to the blastocyst stage (P < or = 0.05) were prevented, at least in part, by culturing oocytes in the presence of DTT (50 microM). Although the mechanism by which DTT exerts its beneficial effects on aged oocytes remains to be elucidated, it may protect oocytes by preventing oxidation of free thiol groups and/or altering a redox-independent signalling pathway that mediates cellular fragmentation and death.