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Biomedical subjects

I Tada

Publications and source records attributed to I Tada.

At least 37 records · Page 2Linked to original sources
PubMed1997

Genetic structure of Trypanosoma cruzi in Central America and its comparison with South American strains.

Genetic characterization by isozyme analysis was performed on 68 isolates of Trypanosoma cruzi; 57 from Guatemala in Central America and 11 from South American countries. Ten zymodemes (isozyme patterns) were identified by examining zymograms of 12 enzymes (13 loci). These zymodemes were classified to 3 major distinctive groups: (1) major Guatemalan, (2) minor Guatemalan and (3) unique South American, by the genetic distances and the phylogenetic dendrogram drawn by UPGMA. Based on the results obtained, genetic structures and phylogenetic relations of T. cruzi in Guatemala and South America are discussed. Clonal reproduction seemed to be consistent with the observation of deviation from Hardy-Weinberg equilibrium in several loci.

Animals↗
PubMed1997

Successful control of onchocerciasis vectors in San Vicente Pacaya, Guatemala, 1984-1989.

Between 1984 and 1989, the onchocerciasis-vector control zone on the pilot area of San Vicente Pacaya, Guatemala, which had been subject to experimental control since 1979, was extended from 91.3 to 148.6 km2. Temephos was used as a larvicide against Simulium ochraceum s.l. the target species. As a new strategy, only breeding sites with water discharges of 0.1-10 litres/s were treated, every 2 weeks. This approach provided a substantial reduction in effort, number of treated sites, time and cost. To assess the effect of the temephos, nine sites were selected in which standardized collections of adult Simulium were made twice a month, by human bait. There was an obvious difference between the pre- and post-control mean densities of flies at each site. In the northern area, which includes the Lavaderos, Barretal, Colina and Rodeo sites, the biting density in 1979, before treatment, varied between 10 and 64 flies/man-hour (FMH). Four years later, this had been reduced to 0.1-3.2 FMH, and by the end of the present study, in 1989, the mean density was zero FMH. In the southern area, which lies south-east of Lavaderos (and includes Guachipilin, Ingerto, Pena Blanca and Sierra Morena), the density during the pre-control phase was 24 FMH at one of the two sites investigated at the time and 39.3 FMH at the other. It fell to 0.1-0.5 FMH after 5 years of control and to zero (three sites) or close to zero (< or = 0.5 FMH; one site) for the last 4 years of the present study. To assess the effect of vector control on onchocerciasis prevalence and incidence, 1280 residents from six endemic communities, out of 12,000 permanent inhabitants, were examined. In Santa Cruz, Patrocinio and Los Rios, the prevalence of skin microfilariae in the subjects from each community fell from 8.1%-37.8% during the pretreatment, base-line period to 0.0%-31.5% when the study foci were totally integrated into the vector-control operation following treatment. Incidence among children (aged < or = 9 years) varied from 0%-25% for the period 1982-1984 but, thereafter, not a single case appeared in four of the six study communities (Santa Cruz, Patrocinio, Los Rios and Berlin). Incidence in Guachipilin did not decline appreciably, probably because of human migration into the area from other onchocerciasis foci. The prevalence of nodules followed a similar trend to those of the prevalence and incidence of skin microfilariae, falling from 9.1%-45.0% pre-control to 1.8%-14.3% 10 years later.

Animals↗
PubMed1996

Rapid expulsion of the intestinal trematodes Echinostoma trivolvis and E. caproni from C3H/HeN mice after infection with Nippostrongylus brasiliensis.

The number of goblet cells in the small intestines of C3H/HeN mice increased rapidly following their infection with about 500 third-stage larvae (L3) of the intestinal nematode Nippostrongylus brasiliensis. The number of goblet cells reached its peak on day 9 postinfection (p.i.). Worm burdens in the hosts' small intestines were determined following a challenge infection with encysted metacercariae of the intestinal trematodes Echinostoma trivolvis or E. caproni on days 8 and 16 after primary infections with N. brasiliensis. All metacercariae of E. trivolvis or E. caproni used to challenge the hosts on day 8 p.i. were expelled. Considerable numbers of E. trivolvis (48.6%) and E. caproni (67.1%) remained in the intestines of hosts challenged with these echinostomes on day 16 p.i. All the controls used for E. trivolvis and E. caproni infections without primary infections with N. brasiliensis showed recovery rates greater than 70%. An enzyme-linked immunosorbent assay (ELISA) showed that the IgM titer rose remarkably and plateaued on day 11 p.i. No marked rise in the IgG or IgA titer occurred during the experiment. These results indicate that mucins increased by hyperplastic goblet cells associated with primary infections with N. brasiliensis are responsible for a rapid expulsion of the worms of the challenge infection with E. trivolvis or E. caproni from the mouse host.

Animals↗
PubMed1996

Rapid expulsion of the intestinal trematodes Echinostoma trivolvis and E. caproni from C3H mice by trapping with increased goblet cell mucins.

Echinostoma trivolvis (Cort, 1914) adults were rejected from C3H mice by 15 days post-exposure, corresponding to the increase in the number of goblet cells. Homologous and heterologous infections with the allopatric species E. caproni (Richard, 1964) were used to confirm the effect of increased secretion of goblet cell mucins in rejecting metacercariae of challenge infections of E. trivolvis or E. caproni on days 10, 16 and 20 p.i. after primary infections of E. trivolvis metacercariae. Five-day-old juveniles of E. trivolvis and E. caproni, which were recovered from C3H mice or hamsters, were also used for challenge infections on day 10 p.i. The metacercariae and juveniles, which were challenged homologously and heterologously on day 10 p.i., were almost all expelled. The metacercariae of E. trivolvis, which were challenged homologously on day 16, were completely rejected, but only a few challenged metacercariae of E. caproni in heterologous infection were recovered. Considerable numbers of E. caproni were recovered when challenge infections with the metacercariae were done on day 20 p.i., while only a small number of E. trivolvis was recovered. All controls without primary infections showed a recovery rate of over 50% of the worms. These results indicate that increased secretion of mucins by hyperplastic goblet cells associated with primary infections of E. trivolvis may be responsible for the expulsion of worms challenged homologously with E. trivolvis and heterologously with E. caproni from the mouse host.

Animals↗
PubMed1995

Cross-resistance between Strongyloides venezuelensis and S. ratti in mice.

Cross-resistance between Strongyloides venezuelensis and S. ratti was tested in mice. The mice were immunized with S. ratti and challenged with infective filariform larvae or larvae recovered from the lungs of mice, of a heterologous species, S. venezuelensis. In this system, cross-resistance was expressed to the intestinal stage but not to the migrating stage of the parasite. Anti-interleukin (IL)-5 monoclonal antibody (mAb) treatment showed that peripheral blood eosinophilia after infection with both species of the genus Strongyloides was dependent on IL-5. Cross-resistance expressed to the intestinal stages was inhibited partially by injection of anti-IL-5 mAb.

Animals↗
PubMed1994

Regulatory effect of anti-interleukin-5 monoclonal antibody on intestinal worm burden in a primary infection with strongyloides venezuelensis in mice.

The intestinal worm burden in Strongyloides venezuelensis-infected mice was influenced by treatment with anti-interleukin-5 (IL-5) monoclonal antibody (NC17) when NC17 was given to mice 3-7 days before infection. The present study has examined the involvement of IL-5 in susceptibility at different in the development of the parasite in the host. The results show that the number of tissue-migrating larvae recovered from the lungs in a primary infection was not affected by anti-IL-5 monoclonal antibody treatment, whereas intestinal worm counts increased in mice treated with 0.25-1 mg of NC17. In mice treated with 0.1 mg of NC17, adult worm recovery was not significantly different from non-treated controls. Peripheral and tissue eosinophilia were not observed in the early phase of infection (days 4-8). Six days after transfer of lung-stage larvae to NC17-treated mice, adult worm recovery was higher than that of control mice. These results suggest that non-eosinophil response(s), which were dependent on IL-5, were involved in the initial establishment of the intestinal stage of S. venezuelensis in mice. We discuss the mechanisms that control the susceptibility to the parasite from the viewpoint of host defence.

Animals↗
PubMed1994

The role of IL-5 in the immune responses to nematodes in rodents.

In this review, Masataka Korenoga and Isoo Toda discuss the role of interleukin 5 (IL-5) in immune responses caused by parasitic infections. Recent studies have shown that eosinophilia in parasitic infections is dependent on IL-5. Although eosinophils have been thought to be potent effector cells (from results of experiments, in vitro), their role in protective immunity to parasites is controversial.

Journal Article↗
PubMed1993

Prolonged normothermic ischaemia of human cirrhotic liver during hepatectomy: a preliminary report.

To evaluate the tolerance of the cirrhotic liver to extended warm ischaemia, 47 patients with cirrhosis who underwent liver resection over a 4-year period were studied retrospectively. Three groups of patients were identified. In group 1 (14 patients) liver resection was performed under conditions of portal triad occlusion ranging from 50 to 75 (mean 57.1) min. Group 2 (12 patients) was treated with portal occlusion for a period ranging from 30 to 42 (mean 33.1) min. Group 3 comprised 21 patients who underwent hepatectomy using conventional techniques. Mean blood loss was significantly reduced by portal triad occlusion (819 ml in group 1, 523 ml in group 2) compared with the conventional technique (1652 ml in group 3) (P < 0.05, group 1 versus group 3; P < 0.01, group 2 versus group 3). Hospital death occurred in three of the 21 patients in group 3 but in no patient who underwent portal triad occlusion. The morbidity rate was lower in the two occlusion groups (four of 26 patients) than in group 3 (six of 21). Bilirubin metabolism was substantially better after surgery in the occlusion groups (P < 0.05, groups 1 and 2 versus group 3 at day 14). Although the serum levels of transaminases were significantly raised until day 3 in patients undergoing long-term occlusion, the cirrhotic liver withstood the ischaemia-reperfusion insult, as assessed by changes in hepatic microcirculation, lipid peroxidation and the morphology of hepatic sinusoids. It is concluded that prolonged ischaemia during liver resection can be sustained in patients with cirrhosis and without high-risk factors.

Adult↗
PubMed1993

Fibrolamellar hepatocellular carcinoma coexistent with a hepatocellular carcinoma of common type: report of a case.

A case of small fibrolamellar hepatocellular carcinoma (HCC) coexistent with a HCC of common type is herein reported. A 56-year-old man was diagnosed as having multi-nodular type HCC with liver cirrhosis. The serum alpha-fetoprotein (AFP) level was slightly increased. The patient underwent a partial caudate lobectomy and lateral segmentectomy. Histologically, both resected tumors were small HCCs measuring less than 2 cm in diameter. One was a fibrolamellar type located in the caudate lobe, while the other was the common type in the lateral segment of the liver. Positive immunohistochemical staining for AFP was observed in the tumor cells of the HCC of common type but was not observed in the fibrolamellar HCC. We also reviewed previously reported cases of fibrolamellar HCC in Japan, and discussed the clinicopathologic implications of this disease.

Carcinoma, Hepatocellular↗
PubMed1993

The expulsion of Echinostoma trivolvis: worm kinetics and intestinal cytopathology in conventional and congenitally athymic BALB/c mice.

The infectivity and distribution of Echinostoma trivolvis were studied in male, conventional and congenitally athymic nude mice, each infected with 30 metacercarial cysts. In conventional mice, worm recoveries at 6 and 8 days post-exposure were 58.3 and 54.0%, respectively. Worm recovery declined to 44.0% by day 10, to 4.3% by day 13, and 0% by day 17. In athymic mice, worm recoveries at 6 and 8 days post-exposure were 61.7 and 36.3%, respectively. Worm recovery declined to 27.7% by day 10, to 0.7% by day 13, and 0% by day 17. The distribution of worms demonstrated a posteriad migration over time in both groups. Kinetic changes in the number of goblet and mucosal mast cells in the upper ileum of mice infected with E. trivolvis were examined. In conventional mice, the number of goblet cells increased rapidly to reach a peak at day 13 and then declined gradually. The number of goblet cells in athymic mice also increased to reach a peak at day 13, and then declined rapidly. However, the number of goblet cells in athymic mice was always less than that in conventional mice. The mast cell number in infected conventional mice increased rapidly to reach a peak at day 17 and then declined. There was no increase in the mast cell number of infected athymic mice throughout the experiment. Whereas common pathological changes occurred in the intestines of both mice groups infected with echinostomes some ultrastructural differences were observed in the gut epithelial cells of conventional versus athymic mice.

Animals↗
PubMed1991

Morphological features of spermatozoa of Paragonimus ohirai (Trematoda: Platyhelminthes) examined by a silver nitrate staining technique.

The mature thread-like spermatozoon of Paragonimus ohirai was shown to be composed of 7 distinct segments which have morphologically different characteristics, following staining with silver nitrate. The first segment (1S) is a needle-shaped structure with a perforatorium. The 2S is composed of two filaments loosely paired; 3S consists of a somewhat coarse thread (vestige of the cytoplasmic projection); 4S is composed of two flagella tightly paired; in 5S, two silver-positive filaments are independently seen as in 2S; 6S has a 'spiral' structure composed of two flagella; in 7S, two filaments are seen dissociated from each other. The sperm nucleus exists within the 'spiral' structure of 6S and this structure may serve to hold and/or protect the nucleus. The technique presented here is useful for gross morphological observations of the long sperm of flatworms.

Animals↗
PubMed1991

[Efficacy of anticancer agent-lipiodol emulsion for hepatic arterial infusion and regional hyperthermia in patients with nonresectable hepatoma].

The efficacy of combination therapy of anticancer agent-Lipiodol Emulsion for hepatic arterial infusion and regional hyperthermia was studied in 102 patients with nonresectable hepatoma. 5-FU, MFA, CDDP and MFA-CDDP were used as anticancer agents in 13, 44, 26 and 19 patients, respectively. One year survival rates of the each group were 9% (1/13, 5-FU-treated), 29% (12/44, MFA-treated), 43% (11/26, CDDP-treated) and 55% (10/19, MFA-CDDP-treated). Tumor regression was found in one out of 11 (9.1%), 11 out 41 (26.8%), 6 out of 23 (26.1) and 9 out of 19 patients (47.4%), respectively. The regional hyperthermia was particularly efficacious for patients with advanced hepatoma (E3 and E4) and clinical stage II, III; 5 out of 32 patients (16%) receiving arterial infusion and hyperthermia survived more than 1 year while all 15 patients without hyperthermia died within 11 months (p less than 0.01). Our data indicate that repeated arterial infusion of MFA and CDDP Lipiodol Emulsion was most effective for nonresectable liver cell cancer, and the regional hyperthermia prolonged the survival of patients who had advanced hepatoma with poor liver function.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Hematopoietic recovery in a patient with acute lymphoblastic leukemia after an autologous marrow graft purged by combined hyperthermia and interferon in vitro.

We describe a patient with acute lymphoblastic leukemia (ALL) in whom hemopoiesis recovered after an autologous marrow graft purged by in vitro hyperthermia. A 17-year-old woman was diagnosed as having ALL in April 1985. After clinical remission was induced, marrow cells were harvested. The marrow cells were treated with hyperthermia at 42.0 degrees C for 1 h in the presence of alpha-interferon to eliminate residual leukemic cells, and then cryopreserved. In January 1990, during her fourth remission she was treated with busulfan and cyclophosphamide, and then received the thawed autologous marrow. Her hematopoietic recovery was prompt with normal trilineage regeneration without any life-threatening complications. She is in good health without evidence of a leukemic relapse at 6 months after autologous bone marrow transplantation. This case suggests that human multilineage progenitor cells retain self-renewal capacity in vivo even after treatment with heat and alpha-interferon in vitro followed by the freezing and thawing procedures.

Adolescent↗
PubMed1991

[Quantitative measuring method for fibers using image processing and analysis].

Previously, the radioisotope labeling and morphometric techniques have been used for the quantitative determination of growth of mandibular condyle by measuring the DNA synthesis or the increased number of cells. However, it is difficult to analyze the dynamics of ESFs (Elastic System Fibers) in the mandibular condyle related to aging, because of changes in the amount, distribution, number of fibers, and density of ESFs. In the present study, therefore, the video-scanning image analyzing technique was used for the quantitative measurement of ESFs in the mouse mandibular condyle. The objects under selected suitable illumination are scanned and focused by the TV camera and lens. The focused image is converted and amplified to obtain the most reliable electric signal by sequential scanning with the relative electronic beam. The original shaded image (electric signals) generated and converted by photo electric converter was filtered by the input slope (detective sensitivity) to detect the relative objects. Next, by inputted contrast, a secondary black-and-white image was detected. Meanwhile, a suitable compensation was also used to eliminate electric noise and dusts by inputting size discrimination. The next step was designed to obtain various quantitative data by measuring areas and diameters of the relative objects after treatment and analyzing of the secondary image, which was outputted from the photo electric converter. The connected LED display showed the measured and counted data, and at the same time the obtained data was automatically printed out for recording. There are many samples that are impossible to distinguish without using specific staining methods, like the ESFs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

The role of interleukin-5 in protective immunity to Strongyloides venezuelensis infection in mice.

We depleted or neutralized interleukin-5 (IL-5) and IL-5 receptor of C57BL/6 mice, using rat anti-murine IL-5 monoclonal antibody (NC17) and anti-murine IL-5 receptor monoclonal antibody (H7). Mice treated with these monoclonal antibodies were infected with Strongyloides venezuelensis larvae. The time-course of faecal egg output and peripheral eosinophilia were monitored. In a primary infection, anti-IL-5 treatment did not affect faecal egg output, although the eosinophil count in peripheral blood was markedly reduced. There was no difference in intestinal worm burden or faecal egg output between anti-IL-5 treated and non-treated mice. In a secondary infection, worms were expelled from the small intestine of anti-IL-5-treated mice as well as from non-treated mice. Worm recovery from the lungs of mice treated with either anti-IL-5 or anti-IL-5 receptor monoclonal antibody was the same as that of normal controls. However, a marked reduction in worm recovery was observed in re-infected mice that had not been treated with monoclonal antibodies. Treatment with anti-IL-5 or anti-IL-5 receptor monoclonal antibody suppressed blood and tissue eosinophilia. Thus the results suggested that the host's protective immunity against tissue-migrating larvae was IL-5-dependent but intestinal immunity was not.

Animals↗