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Biomedical subjects

R Eliasson

Publications and source records attributed to R Eliasson.

At least 73 records · Page 4Linked to original sources
PubMed1978

Inhibition of primase, the dnaG protein of Escherichia coli by 2'-deoxy-2'-azidocytidine triphosphate.

2'-Deoxy-2'-azidocytidine-5'-triphosphate was investigated as an inhibitor in two reconstructed enzyme systems which catalyze the replication of two viral DNAs. During replication of the duplex replicative form of phiX174 DNA, DNA polymerase III holoenzyme was weakly inhibited and inhibition was reversed by dCTP. A more pronounced inhibition, not reversed by either dCTP or CTP, was observed during replication of the single-stranded DNA of the bacteriophage G4, a close relative of phiX174. This effect depended on the incorporation of 2'-deoxy-2'-azidocytidine-5'-triphosphate by primase (dnaG protein) which synthesizes a 29-residue RNA primer at the unique origin of bacteriophage G4 DNA replication. Extension of the primer strand, terminated by 2'-deoxy-2'-azidocytidine-5'-triphosphate is then severely inhibited. Primase was also inhibited by the 2'-deoxy-2'-azido derivatives of ATP, GTP, and UTP.

Coliphages↗
PubMed1978

Formation of Okazaki fragments in polyoma DNA synthesis caused by misincorporation of uracil.

When dUTP replaced dTTP during polyoma DNA replication in isolated cell nuclei, radioactivity from labeled deoxynucleoside triphosphates was almost exclusively recovered in very short Okazaki fragments and incorporation ceased after a short time. Addition of uracil, a known inhibitor of the enzyme uracil-DNA glycosidase (Lindahl et al., 1977), increased total synthesis and shifted the incorporation to longer progeny strands. The presence of as little as 2.5% of dUTP in a dTTP-containing system gave a distinct increase in isotope incorporation into Okazaki pieces accompanied by a corresponding decrease in longer strands. This effect was reversed completely by uracil. The short strands formed from dUTP could be chased efficiently into long strands. Our results suggest that dUTP can be incorporated in place of dTTP into polyoma DNA, and that polyoma-infected nuclei, similar to E. coli (Tye et al., 1977), contain an excision-repair system which by removal of uracil causes strand breakage and under certain circumstances may contribute to the formation of Okazaki fragments.

DNA, Viral↗
PubMed1978

On the pathogenesis of obstructive lung disease. A study on the immotile-cilia syndrome.

The role of mucociliary transport in man can be evaluated by studying persons with the recently recognised "immotile-cilia syndrome". Such persons have chronic or recurrent infections of the upper and lower airways and have ultrastructural defects of cilia and sperm tails. Men suffering from the syndrome usually are sterile and have immotile spermatozoa. About half of the subjects have complete situs inversus. Fourteen persons with the immotile-cilia syndrome have been studied here in an attempt to evaluate the role of an impaired mucociliary transport for the development of obstructive lung disease. Age range was 25-40 years; there were ten men and four women. Mucociliary transport in the lungs was extremely slow in all subjects. Spirometry demonstrated airway obstruction in nine subjects. Two of these subjects had radiological evidence of pulmonary emphysema. The results indicate that an absent mucociliary transport predisposes to the development of obstructive lung disease. Patients with classic chronic bronchitis have earlier been shown to have a severely impaired mucociliary transport. The present findings in subjects with primary ciliary immotility make it probable that this impaired mucociliary transport is of pathogenetic importance for development of the obstructive lung disease often found in patients with chronic bronchitis.

Adult↗
PubMed1977

The immotile-cilia syndrome. A congenital ciliary abnormality as an etiologic factor in chronic airway infections and male sterility.

We investigated six men and a woman suspected of suffering from congenital immotility of cilia. All had chronic airway infections, and the men had immotile spermatozoa. The woman and three men had Kartagener's syndrome. The investigations included measurements of the mucociliary transport in the lower airways and ultrastructural studies of the sperm tails or respiratory cilia (or both). Mucociliary transport was significantly delayed. Sperm tails lacked dynein arms in five patients. Respiratory cilia from the women and two men lacked dynein arms and were irregularly oriented. The results support the hypothesis that a congenital defect in the cilia and sperm tails will cause chronic respiratory-tract infections and male sterility--the immotile-cilia syndrome. In about half these patients there will also be a situs inversus--i.e., Kartagener's syndrome.

Adult↗
PubMed1976

Concentrations of doxycycline in human seminal plasma.

Single oral doses of 200 mg doxycycline was given to 16 healthy test subjects. The concentrations of the drug were measured in blood plasma and seminal plasma and related to the zinc content. Measurable concentrations of doxycycline were obtained in seminal plasma one to two hours after drug intake. The maximum level was reached after 4 to 6 hours and measurable concentrations were recorded in both blood plasma and seminal plasma after 24 hours. This means that measurable concentrations were maintained during almost the entire dose interval. In split ejaculate experiments it was shown that doxycycline is excreted mainly through the prostate gland. The mean concentration ratio for "prostatic fluid" vs. blood plasma in healthy volunteers was about 0.6. Indirect evidence is presented that the concentrations in the fluids from the accessory genital glands are higher if patients with prostatitis are given daily doses of 100 mg doxycycline.

Administration, Oral↗
PubMed1975

Lack of dynein arms in immotile human spermatozoa.

Sermatozoa from two brothers who are not twins were found to be straight and immotile. Examinations of the sperm showed that oxygen consumption and lactic acid production were normal; viability tests showed that the percentage of dead sperm was not increased. The ultrastructural appearance of the sperm tail was normal except for a complete lack of dynein arms and some irregularities in the arrangement of the accessory fibers and the longitudinal columns of the fibrous sheath. The mitochondrial apparatus and the sperm head conform to the conventional model. According to the sliding-filament hypothesis first proposed by Afzelius (1959. J. Biophys. Biochem. Cytol. 5:269.), the arms are responsible for the bending movements of the tail. The simplest explanation for the simultaneous lack of arms and sperm motility appears to be that the two brothers have a genetic disorder involving production, assembly, or attachment of the dynein arms.

Adult↗
PubMed1975

Semen cahracteristics before and after ligation of the left internal spermatic veins in men with varicocele.

The semen from 20 men with varicocele was studied before and after surgical correction of the varicocele. The effect on sperm quality was only marginal and could not explain the fairly high conception rate (20%) after operation. The recommendation that varicocele in men with long-term infertility should be eliminated by ligation of the internal spermatic veins is still justified despite the absence of positive effects on sperm quality.

Acid Phosphatase↗
PubMed1975

Absorption activity of the blood group substances in various fractions of split ejaculates from man.

Antigens of the ABO system have been determined in the various fractions of split ejaculates from three A and two O (H) men who were secretors. The activity of the antigen was determined by a hemagglutination inhibition test. Within a split ejaculate the various fractions contained almost the same antigen activity, indicating that the antigens were secreted from all the glands contributing to the seminal plasma.

ABO Blood-Group System↗