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Biomedical subjects

K Katakura

Publications and source records attributed to K Katakura.

At least 37 records · Page 2Linked to original sources
PubMed1996

Functional properties of murine macrophages promoted by nerve growth factor.

The stimulating effect of nerve growth factor (NGF) on phagocytosis, parasite killing, and interleukin-1beta (IL-1beta) production of murine peritoneal macrophages was assessed. In the presence of various doses of NGF, macrophages showed the increased phagocytosis of both nonspecific hydrophilic microspheres and sheep red blood cells (SRBC) opsonized with anti-SRBC antibodies (Ab) or complement in a dose-dependent manner. NGF also enhanced killing of Leishmania donovani promastigotes by macrophages, and its ability was comparable with that of an optimal dose of recombinant granulocyte-macrophage colony-stimulating factor or recombinant interferon-gamma. The addition of NGF to peritoneal macrophages and monocyte-macrophage J774A.1 cells led to a significant release of IL-1beta in a dose-dependent manner and expression of IL-1beta mRNA. Because pretreatment of peritoneal macrophages and J774A.1 cells with K-252a, a tyrosine kinase inhibitor, completely suppressed these NGF-mediated stimulating effects and p140trk phosphorylation and because flow cytometric analysis with specific Ab against two distinct NGF receptors showed the expression of p140trk, unlike p75LNGFR, on the surface of macrophages, the stimulating activity of NGF to murine macrophages may be mediated through p140trk. Thus, NGF may act as an activator for murine macrophages in the process of inflammatory and immune actions.

3T3 Cells↗
PubMed1996

Eosinophil chemotactic activity in Leishmania amazonensis promastigotes.

Tissue eosinophilia was observed in the subcutaneous tissue of mice shortly after their inoculation not only with living but also with lysed promastigotes of Leishmania amazonensis. Intraperitoneal inoculation of lysed promastigotes from five different Leishmania species (L. donovani, L. chagasi, L. tropica, L. amazonensis, and L. braziliensis) induced eosinophil accumulation in the mouse peritoneum. This eosinophil infiltration was also detected in C5-deficient AKR mice, indicating complement independent eosinophil chemotaxis by the parasite. The induced eosinophils were hypodense, suggesting activation of the cells. Finally, we demonstrated in vitro eosinophil chemotactic activity in the promastigote lysates using purified eosinophils and blind well chambers. These results suggest the presence of an eosinophil chemotactic factor in Leishmania, a protozoan parasite.

Animals↗
PubMed1995

[A case of multiple cerebral mycotic aneurysms treated with endovascular surgery].

A case of multiple mycotic cerebral aneurysms successfully treated with endovascular surgery is reported. A nine-year-old boy who has suffered from hypertrophic obstructive cardiomyopathy and active infectious endocarditis in the mitral valve developed sudden consciousness disturbance and convulsion. Computerized tomography revealed subarachnoid hemorrhage with subcortical hematoma in the left parietal lobe. Angiography demonstrated four aneurysms at the distal part of the middle cerebral artery on both sides. Since his physical status had been deteriorating, it was difficult to undergo a usual surgical operation. Therefore, endovascular surgery was performed. The catheter was super-selectively advanced to the parent artery of the left posterior parietal artery aneurysm which seemed to be the hemorrhagic source, and the embolization was performed using platinum coils and liquid embolization material. Angiography after embolization showed that the aneurysms had been successfully occupied by the materials while the aneurysm of the right anterior parietal artery had not responded antibiotic therapy. Therefore the second embolization was carried out to the parent artery of the aneurysm of the right anterior parietal artery one month later. The patient had no neurological deficit after embolization and no aneurysms have been detected by the follow-up angiogram after the second embolization. An endovascular approach might be an alternative useful treatment for cases in which the patient has, deteriorated so much that it is considered difficult to perform open craniotomy under general anesthesia.

Aneurysm, Infected↗
PubMed1993

Failure of treatment with alpha-difluoromethylornithine against secondary multilocular echinococcosis in mice.

In AKR/J mice inoculated intraperitoneally with protoscoleces of Echinococcus multilocularis, the oral administration of alpha-difluoromethylornithine (DFMO) in drinking water had no obvious effect on the development of hydatid cysts. The DFMO treatment also caused no apparent depletion of three major polyamines (putrescine, spermidine, and spermine) in the cysts, although a slight reduction in the putrescine level was detected. The failure of DFMO treatment to reduce the growth of cysts in mice may result from the absence of ornithine decarboxylase in the parasite.

Animals↗
PubMed1993

Immune defense and eosinophilia in congenitally IgE-deficient SJA/9 mice infected with Angiostrongylus costaricensis.

The roles of IgE in protective immunity and eosinophilia in Angiostrongylus costaricensis infection were examined by comparing IgE-deficient SJA/9 mice and IgE-producing SJL/J mice. In primary infection, mean total IgE levels increased to a maximum of 390 ng/ml, which was more than 10 times greater than the 29 ng/ml measured preinfection in SJL/J mice but less than the 10 ng/ml found in SJA/9 mice throughout the experiment. Immune defense as determined by recovery of adult worms and eosinophilia were similar in SJL/J and SJA/9 mice. Protective immunity was induced by infection with A. costaricensis followed by treatment with levamisole for 4-6 days postinfection. After the challenge infection, the numbers of adult worms and eosinophils in SJA/9 mice were not significantly different from those in SJL/J mice. Anti-A. costaricensis IgE antibody was not detected in either strain of mice during the experiment. These results indicate that A. costaricensis infection induced the production of IgE not specific for parasite antigens in IgE-producing mice. Potentiated nonspecific IgE played no significant role in immune defense and eosinophilia.

Angiostrongylus↗
PubMed1993

Cutaneous leishmaniasis in mast cell-deficient W/Wv mice.

Genetically mast cell-deficient W/Wv mice infected with Leishmania amazonensis showed progressive development of ulcerative skin lesions. However, no significant differences between the W/Wv mice and the normal littermates with respect to size of the lesions, anti-Leishmania immunoglobulin E antibody, and the number of eosinophils accumulated in the lesions were observed.

Animals↗
PubMed1993

Molecular karyotype characterization of Leishmania panamensis, Leishmania mexicana, and Leishmania major-like parasites: agents of cutaneous leishmaniasis in Ecuador.

Molecular karyotypes of Leishmania isolates from patients with cutaneous leishmaniasis in Ecuador were analyzed by pulsed-field gel electrophoresis (PFGE) and Southern blot hybridization. The DNA karyotypes of L. major-like parasites were similar between two human isolates from a lowland coastal and a highland Andean region, but were apparently different from those of eleven World Health Organization reference strains including L. major. The smallest chromosome of 240 kilobases in L. major-like parasites was found to belong to the 715-class of small linear chromosomal DNAs, which have been shown to appear in some lines of Leishmania. Chromosome banding patterns of L. mexicana isolates exhibited a novel, ordered, chromosomal ladder, and were identical among four human isolates and one canine isolate from a restricted geographic region in the Andes. On the other hand, minor chromosome size polymorphisms were observed among three L. panamensis isolates from different endemic regions near the Pacific Coast. Chromosomal locations of dihydrofolate reductase-thymidylate synthetase and P-glycoprotein genes revealed further differences in chromosomal organizations among these Leishmania species in Ecuador. These results indicate that karyotype analysis by PFGE is useful for epidemiologic studies of leishmaniasis in Ecuador.

Animals↗
PubMed1992

[Advances in molecular parasitology].

Recent studies on molecular biology of parasites revealed novel mechanisms for the control of expression of parasitic genes. In trypanosomatid protozoa, unusual characteristics of gene regulation, including polycistronic transcription, trans-RNA splicing and RNA editing have been discovered. This review describes the recent progress of RNA editing in trypanosomes, and trans-splicing in both trypanosomes and nematodes. Studies of the editing of mRNAs in trypanosomatid mitochondria indicate the involvement of small guide RNA molecules, which are encoded in the minicircles and/or maxicircles of kinetoplast DNA. A proposed transesterification model for RNA editing suggests an analogous reaction between RNA editing and RNA splicing. In addition, the development of stable transfection system and success of homologous gene targeting in Trypanosoma and Leishmania are reported.

Animals↗
PubMed1991

Tunicamycin-resistant variants from five species of Leishmania contain amplified DNA in extrachromosomal circles of different sizes with a transcriptionally active homologous region.

Twelve independent variants were selected from five species of Leishmania for resistance to tunicamycin by exposure of cultured promastigotes to increasing concentrations of this antibiotic, an inhibitor of the microsomal N-acetylglucosamine-1-phosphate transferase in the dolichol pathway of N-glycosylation. All variants obtained from all species, as found previously with Leishmania amazonensis, contain amplified chromosomal DNA exclusively as extrachromosomal circles. These circular amplicons hybridize with amplified DNAs cloned previously from tunicamycin-resistant Leishmania amazonensis, but not with those from Leishmania resistant to other drugs. The amplicons from tunicamycin-resistant cells vary with different species in size from 30 to 70 kb, but all share a homologous region of 20 kb. Multiple independent transcripts are overexpressed from this region. Elevation of the microsomal glycosyltransferase activity is demonstrated in these variants from representative species. The results thus provide further evidence that this enzyme is overexpressed due to amplification of the gene in these cells. The consistent observation of this event in all cases studied also suggests that this is the predominant, if not the only mechanism of tunicamycin resistance in Leishmania.

Animals↗
PubMed1990

Effects of ultraviolet B irradiation on lenticular riboflavin metabolism and high-molecular-weight-protein aggregation.

We investigated the effects of ultraviolet B (UVB) irradiation on the formation of ester forms of riboflavin and of high-molecular-weight (HMW) protein aggregates and on lenticular riboflavin-binding capacity (LRBC). Esterification of riboflavin decreased as the duration of UV irradiation increased, suggesting the irradiation-induced denaturation of the apoenzyme of synthetases of ester forms of riboflavin. UVB irradiation of lens homogenate supplemented with riboflavin increased LRBC and the formation of HMW protein aggregates, while gamma-crystallin was decreased. These results are consistent with those of our earlier studies in which we obtained data suggesting that, upon exposure of rat lens homogenate to fluorescent light, photosensitized riboflavin may bring about cross-linking of lens protein. Our data demonstrate that the photosensitivity of lenticular riboflavin is increased by longer periods of UV irradiation.

Animals↗
PubMed1989

DNA amplification in arsenite-resistant Leishmania.

Arsenite-resistant variants of a trypanosomatid protozoan, Leishmania mexicana amazonensis, were selected in vitro by stepwise increases of sodium arsenite concentrations up to 30 microM in the culture medium. These variants were found to contain amplified DNA as extrachromosomal supercoiled molecules of about 69 kb. They originate from a single chromosome in the wild-type cells. There is evidence of chromosomal changes in these cells associated with the selection for arsenite resistance. The apparent absence of these circular molecules in the wild type and their loss from the drug-sensitive revertants suggest amplification of chromosomal DNA into these extrachromosomal circles as the mechanism of arsenite resistance.

Animals↗
PubMed1988

A new method of measuring in vivo sound speed in the reflection mode.

This paper describes a new method for in vivo sound measurement in the reflection mode. The mean sound speed between the reflector and linear array transducer is measured using the following three parameters: time of flight, time of flight difference, and distance between two receiver elements. To detect time of flight, the system delay-line time compensator is adjusted to obtain the sharpest reflector image. This method was evaluated in vivo in human livers, specifically 26 normal, 27 cirrhotic, and 15 fatty livers. The mean sound speed between diaphragm and the transducer was obtained. The measured sound speed was significantly higher in cirrhotic livers and lower in fatty livers.

Fatty Liver↗
PubMed1988

Protective immunity and eosinophilia in IgE-deficient SJA/9 mice infected with Nippostrongylus brasiliensis and Trichinella spiralis.

To elucidate the roles of IgE antibody in host responses to helminth infection, selective IgE-deficient SJA/9 mice were infected with the nematode parasites Nippostrongylus brasiliensis, which elicits remarkable potentiated IgE production, and Trichinella spiralis, which induces strong anti-Trichinella IgE antibody production in normal mice. The kinetics of blood eosinophilia, worm burden after primary infection, and resistance to secondary infection in SJA/9 mice were the same in both infections as those in congenic SJL/J mice used as an IgE-producing control. These results indicate that the host responses examined here operate under IgE-independent mechanisms.

Animals↗
PubMed1988

Acid phosphatase activity of virulent and avirulent clones of Leishmania donovani promastigotes.

Virulent and avirulent clones of Leishmania donovani promastigotes were examined for their acid phosphatase activity. The acid phosphatase activity of whole-cell lysates of virulent clones was 1.5 to 2.0 times higher than that of avirulent clones. Pellet fractions (260,000 x g, 30 min) from sonicated promastigotes of a virulent clone and an avirulent clone contained 60 and 40% of the total enzyme activity, respectively. Membrane-bound acid phosphatase was extracted with Triton X-100 from the pellet. This membrane-bound phosphatase activity was 2.4-fold higher in virulent organisms than in avirulent organisms. The membrane acid phosphatase exhibited two distinct bands on polyacrylamide gels stained for enzyme activity. One diffuse, faster-migrating band showed identical electrophoretic mobility in both virulent and avirulent clones, although a higher enzymatic activity was observed with the extract from virulent cells. In contrast, a slower-migrating band was different between the two clones in the mobility. These results suggest that membrane-bound acid phosphatase was quantitatively and qualitatively different between virulent and avirulent promastigotes of L. donovani. In addition, virulent cells produced a relatively high level of acid phosphatase throughout the growth in culture.

Acid Phosphatase↗
PubMed1986

Human case of dracunculiasis in Japan.

Dracunculus medinensis was recovered from a 42-year-old man residing in Shizuoka, Japan. Part of an adult female worm was removed from an abscess in the subcutaneous tissue on his right gastrocnemial muscle. The worm's morphology and that of the embryos found in its uterus revealed that the parasite was Dracunculus medinensis. This is the first human case of dracunculiasis acquired in Japan.

Adult↗
PubMed1984

[Surgical treatment of cerebral paragonimiasis miyazakii].

An operated case of cerebral paragonimiasis miyazakii was reported. A 25-year-old man was admitted to our hospital on Jan. 25, 1982, because of weakness, sensory disorder and focal convulsion of the right upper limb. He complained of slight headache but had no sign of meningeal irritation nor inflammation. CT scan revealed a left parietal low density mass with irregular ring-like contrast enhancement. Left carotid angiogram showed stretched arteries around the mass. Laboratory findings were normal except for eosinophilie (17%). Chest X-P was normal. Operation was performed under diagnosis of glioblastoma on Aug. 6, 1982. The tumor was well-circumscribed and had a firm capsule which containing necrotic substance. The tumor was removed totally and the bone flap was also removed since slight brain swelling was seen. Histologically it proved to be a granuloma and four eggs of helminth were found in the necrotic tissue. Post operative state of the patient was satisfactory and cranioplasty was performed 3 weeks later. On Aug. 31, he began to complain of chest pain, cough and hemosputum, and chest X-P disclosed a nodular shadow in the lower lobe of the right lung. Paragonimiasis was strongly suspected because he had a history of having three fresh-water crabs (Potamon dehaani) 18 months before. But not egg was found in either sputum nor stool. Skin test with paragonimus westermani antigen was highly positive.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗