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Biomedical subjects

K Shimada

Publications and source records attributed to K Shimada.

At least 1,531 records · Page 85Linked to original sources
PubMed1979

Lambda bacteriophage-mediated transduction of ColE1 deoxyribonucleic acid having a lambda bacteriophage-cohesive end site: selection of packageable-length deoxyribonucleic acid.

An in vitro recombinant ColE1-cos lambda deoxyribonucleic acid (DNA) molecule, pKY96, has 70% of the length of lambda phage DNA. The process of lambda phage-mediated transduction of pKY96 generated a small amount of transducing phage particles containing ColE1-cos lambda DNA molecules of 80 or 101% of the length of lambda phage DNA, in addition to those containing original pKY96 DNA molecules. The newly isolated larger plasmid DNAs were transduced 100 times more efficiently than pKY96 DNA. Their structures were compared with that of a prototype pKY96 DNA, and the mechanism of the formation of these molecules is discussed.

Bacteriophage lambda↗
PubMed1979

Location of a ColE1 deoxyribonucleic acid region that affects the plaque-forming ability of lambda-ColE1 hybrid bacteriophage.

The plaque-forming ability of a hybrid phage between plasmidColE1 and phage lambda carrying amber mutations in genes O and P was inhibited by the presence of ColE1 in suppressor-deficient Escherichia coli cells. ColE1 deoxyribonucleic acid regions concerned with this inhibition were examined by using various deletion and transposon insertion derivatives of ColE1, and it was found that the presence of the deoxyribonucleic acid region extending between 420 and 613 base pairs upstream from the initiation site of ColE1 deoxyribonucleic acid replication (J. Tomizawa, H. Ohmori, and R. E. Bird, Proc. Natl. Acad. Sci. U. S. A. 74: 1865--1869, 1977) was essential for this function.

Bacteriophage lambda↗
PubMed1979

Cardiac atrial myosin adenosine triphosphatase of animals and humans: distinctive enzymatic properties compared with cardiac ventricular myosin.

Cardiac myosin obtained from atria had a higher Ca2+-activated ATPase activity than did cardiac myosin from ventricles in various species of animals and in humans. The increased specific activity of Ca2+-activated adenosine triphosphatase (ATPase) of atrial myosin appeared to correlate with the level of the activity of ventricular myosin ATPase in the animal, since the same order in ATPase activity, as observed in ventricular myosins from various animals, was noted in atrial myosins. The enzymatic properties of atrial myosin also were characterized by no activation by N-ethylmaleimide, low activating energy, and a lower rate of inactivation at alkaline pH compared with the same properties of ventricular myosin. These findings suggest a difference in the myosin molecule at or near the active site, involving some sulfhydryl groups, between the two types of cardiac myosin. The Mg2+-activated ATPase activity, both in the presence and absence of actin (which is thought to be closely related to the basic contraction mechanism), also was enhanced in atrial myosin. Thus, the ATPase activities of atrial and ventricular myosins were different with special reference to the reaction pathway involving calcium and magnesium ions and appear to account for the difference in the velocity of contraction between the atria and the ventricles.

Adenosine Triphosphatases↗
PubMed1979

[Bacteriological and clinical studies on metronidazole in Bacteroides fragilis infections (author's transl)].

The antimicrobial activity of 24 Bacteroides fragilis, 13 Bacteroides thetaiotaomicron and 5 Bacteroides vulgatus, all of which were recent clinical isolates, was determined by the agar dilution technique. These three species had similar susceptibility patterns, but the B. thetaiotaomicron strains were generally less susceptible than the B. fragilis strains. Clindamycin was very active against 81% of the Bacteroides strains at 3.1 mcg/ml of less while 21% of the Bacteroides strains had MICs of 100 mcg/ml or above. Metronidazole was active against all Bacteroides strains at 1.6 mcg/ml or less. The patients with decubitus ulcers and B. fragilis septicemia, who responded satisfactorily to the combination of metronidazole and tobramycin, were presented.

Aged↗
PubMed1979

A determination of H2O2 release by the treatment of human blood polymorphonuclear leukocytes with myristate.

Free H2O2 released from human blood leukocytes during phagocytosis into the extracellular medium was highly reactive with the ferric form of HRP, forming an enzyme-substrate complex which was identical to HRP-H2O2 compound II. The formation of HRP-H2O2 compound II was employed for assaying the rates of H2O2 release by leukocytes upon addition of bacteria or myristate. The treatment of normal human blood leukocytes with myristate resulted in a marked stimulation of H2O2 release compared to phagocytizing cells. The activity of H2O2 release in response to myristate was found to be deficient in the leukocytes of two patients with chronic granulomatous disease. This assay method with myristate supplementation is so sensitive and specific that it should be useful for the diagnosis of chronic granulomatous disease.

Adult↗
PubMed1979

Complement response after experimental bacterial infection in various nutritional states.

In malnourished rats, nutritionally rehabilitated rats at various stages, and in well nourished rats, levels of serum complement after bacterial infection caused by Staphylococcus aureus, as well as tuberculin reactivity, were examined. The elevation of complement showed a peak 2--3 days after infection, herein called the first complement response. A reelevation occurred at a later stage, 7--14 days after infection, and is referred to as the second complement response. The first complement response was observed in all the rats after Staphylococcus aureus infection but it was greater in well nourished rats. In malnourished rats, only the first complement response was observed and the tuberculin reaction and second complement response were lacking. After 1 week of nutritional rehabilitation, 40% of the rats showed recovery of tuberculin responses and both the first and second complement responses were observed. Nutritionally rehabilitated rats treated longer than 2 weeks, together with the well nourished control rats, showed positive tuberculin reactivity. The second complement response was also observed in such rats when bacterial infection was severe but not with mild infection.

Animals↗