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K Tanabe

Publications and source records attributed to K Tanabe.

At least 469 records · Page 26Linked to original sources
PubMed1988

Physical and genetic mapping of the Salmonella dublin virulence plasmid pSDL2. Relationship to plasmids from other Salmonella strains.

Plasmids of approximately 80 kb in size are found in nearly all clinical isolates of Salmonella dublin and are believed to be essential for virulence. We have shown previously that the 80-kb plasmid pSDL2 is required for the S. dublin Lane strain to establish a lethal systemic infection in BALB/c mice after oral or intraperitoneal inoculation. We now present a physical and genetic characterization of pSDL2. We have established a complete restriction endonuclease cleavage map of pSDL2 for five enzymes: Xba I, Bam HI, Xho I, Sal I, and Hind III. The region specifying autonomous replication has been localized to a 10.5-kb region of the Sal I A fragment by subcloning on the vector pBR322. Using transposon insertion mutagenesis with Tn5-oriT, a region encoding the virulence phenotype has been mapped within a 6.4-kb portion of the Sal I B fragment. Deletions generated by partial Eco RI restriction digestion demonstrate that at least 50 kb of the plasmid DNA are not required for replication or virulence functions, confirming the map location of these phenotypes. Plasmids of different sizes and restriction patterns were found in mouse virulent strains of S. dublin Vi+, S. enteritidis, and S. choleraesuis. By Southern hybridization, these putative virulence plasmids share a common 4-kb Eco RI fragment with the virulence region of pSDL2, and the plasmids from S. dublin Vi+ and S. enteritidis were shown to express mouse virulence comparable to pSDL2.

Cloning, Molecular↗
PubMed1988

[Molecular weight and fragmentation of human chorionic gonadotropin in urine in patients with trophoblastic diseases].

Molecular weights (MW) of urinary human chorionic gonadotropin (hCG) from trophoblastic diseases were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), followed by Western blotting using specific antibodies. Although the MW of hCG beta from hydatidiform mole and invasive mole were identical to that of standard hCG beta, those from choriocarcinoma were individually different. These results indicate that the structural changes of carbohydrates, which may be induced by malignant transformation of trophoblast, can be reflected as differences in MW. In SDS-PAGE under nonreducing conditions. Western blotting using anti-hCG beta-carboxy-terminal peptides (CTP) revealed a single band corresponding to hCG beta. Under reducing conditions with dithiothreitol (DTT), however, a second low MW material (CTP') could be observed with anti-hCG beta-CTP. All hCG samples from invasive mole and choriocarcinoma were much more susceptible than standard hCG to release of CTP' by DTT. Estimation of MW and susceptibility to DTT reducing of urinary hCG by Western blotting are useful in the diagnosis of invasive mole and choriocarcinoma.

Chorionic Gonadotropin↗
PubMed1988

Metabolic effects of 3'-deoxyadenosine (cordycepin) and 2-halo-3'-deoxyadenosine on repair of X-ray-induced potentially lethal damage in Chinese hamster V79 cells.

Using cultured Chinese hamster V79 cells, an attempt has been made to examine the phosphorylation of cordycepin and its 2-halo derivatives (2-chloro-3'-deoxyadenosine, 2-bromo-3'-deoxyadenosine, and 2-iodo-3'-deoxyadenosine) by adenosine kinase, within the cells, and to correlate it with their cytotoxicities and abilities to inhibit the repair of X-ray-induced potentially lethal damage (PLDR). Of all compounds, only cordycepin was found to be phosphorylated and showed both potent cytotoxicity and ability to inhibit PLDR.

2-Chloroadenosine↗
PubMed1987

Allelic dimorphism in a surface antigen gene of the malaria parasite Plasmodium falciparum.

Merozoites of the malaria parasite Plasmodium falciparum carry surface proteins processed from a precursor termed p190 or p195. Polymorphism has been reported in this protein. Since the protein is a candidate for a malaria vaccine, it is important to understand the nature of this polymorphism. We have determined the complete nucleotide sequence of the p190 gene from the MAD20 strain (a Papua New Guinea isolate). Comparisons of the gene with that from other strains of P. falciparum allowed us to study the genetic basis of the antigen's polymorphism. The gene consists of sequences distributed in variable blocks, which are separated by conserved or semi-conserved sequences. Variable sequences occur both in regions that code for tripeptide repeats and in regions with no apparent repeats. Interestingly, according to the present data, variable sequences are not widely polymorphic but fall into two distinct types. We argue that the p190 protein is encoded by dimorphic alleles capable of limited genetic exchange and present evidence at the nucleotide level documenting intragenic recombination in Plasmodium.

Alleles↗
PubMed1987

Estimation of the distribution profile of airway resistance in the lungs.

The distribution profile of resistance in a series lung model consisting of airways of 23 generations with alveoli was estimated in 10 healthy subjects and 7 subjects with chronic pulmonary emphysema. Forced oscillation was applied to the subjects at the mouth using a complex wave composed of sine waves at frequencies through the range 4 to 20 Hz in 1-Hz steps. The pleural pressure was measured with a catheter-tip micromanometer, which was installed in an esophageal balloon. The frequency dependency of the pulmonary impedance was analyzed using a penalty function method, and a stable estimate of the distribution profile of resistance in the lungs was thus obtained. The central airway resistance (defined as the resistance from generation 0 to generation 7) was estimated as 1.18 +/- 0.37 cm H2O/liter/sec in the healthy subjects and 1.03 +/- 1.13 cm H2O/liter/sec in the subjects with chronic pulmonary emphysema. The peripheral airway resistance (defined as the resistance from generation 8 to generation 23) was estimated as 0.06 +/- 0.03 cm H2O/liter/sec in the healthy subjects and 6.38 +/- 3.77 cm H2O/liter/sec in the subjects with chronic pulmonary emphysema.

Adult↗
PubMed1987

A method for monitoring the viability of malaria parasites (Plasmodium yoelii) freed from the host erythrocytes.

The viability of erythrocyte-free malaria parasites (Plasmodium yoelii) was assessed with the cationic fluorescent dye, rhodamine 123 (R123). Parasites were freed from infected mouse erythrocytes either by saponin lysis or by Tris-ammonium chloride lysis and incubated with R123 at 37 degrees C. The parasite-associated dye was extracted with iso-butanol and measured with a fluorescent spectrophotometer. R123 accumulated intensely in free parasites prepared by saponin lysis but only weakly in those prepared by Tris-NH4Cl. Very little dye accumulated in free parasites fixed with 2% glutaraldehyde or with 3.7% formaldehyde, or in those heated at 50 degrees C for 15 min. Similar results were obtained by observations with an epifluorescent microscope. Free parasites incubated in hypotonic solutions did not accumulate the dye. Only parasites intensely accumulating R123 incorporated [3H] hypoxanthine. These results indicate that only living parasites are stained with R123, which can therefore be used to monitor the viability of erythrocyte-free malaria parasites.

Animals↗
PubMed1987

Detection of circulating antigens of Pneumocystis carinii in human sera by a sandwich enzyme-immunoassay.

A countercurrent immunoelectrophoresis test has been used for detection of circulating antigens of Pneumocystis carinii in humans; however, this study describes another experiment by sandwich enzyme-immunoassay. Antiserum was prepared by immunizing rabbits with P. carinii cysts which had been propagated in athymic nude rats. Profiles of time course in patients with the positive antigenemia show that P. carinii antigens are detectable prior to an onset of acute pneumonia. Since the sandwich enzyme-immunoassay has an ability of comparing serially monitored levels of the antigen in a quantitative value, the method is to be widely used as a clinical laboratory examination.

Animals↗
PubMed1987

Clinical evaluation of antimalarial regimens in Japan.

The actual situation of the treatment of malaria for the past 10 years in Japan was investigated and analyzed. As a result, it was revealed that there were not a few cases which had been treated improperly probably because of the difficulty of getting antimalarial agents. Moreover, it was made clear that the death rate on falciparum malaria was constantly high, 8.7%, as expected and the relapse rate of vivax malaria was still as high as 18.0%. There was the recrudescence of falciparum malaria at 8.1%, maybe because of the influence of the prevalence of the drug-resistant strains of Plasmodium falciparum. The trouble in getting antimalarial agents has been overcome since 1980. Study Group on Pharmacotherapy of Imported Tropical Diseases was organized by the Ministry of Health and Welfare in 1980, and antimalarial agents have been supplied free of charge through the Study Group for the treatment of the disease. The number of cases of imported malaria has increased in our country. There are a lot of problems to be solved quickly to cope with the situation: people who travel abroad should be enlightened on the danger of the infection of malaria and take prophylactics for the disease and physicians should get familiar with the disease being supplied with information about it.

Animals↗
PubMed1987

Modifications of primaquine as antimalarials. 4. 5-Alkoxy derivatives of primaquine.

Thirty-two 5-alkoxyprimaquines have been synthesized and evaluated as blood schizonticides (Plasmodium berghei, mouse) and tissue schizonticides (Plasmodium cynomolgi, monkey). Several of these compounds were extremely active in both screens. Such a broad spectrum of antimalarial efficacy offers the possibility of a single drug that could cure the various relapsing and nonrelapsing malarias.

Animals↗