Biomedical subjects

T Mikami

Publications and source records attributed to T Mikami.

At least 73 records · Page 4Linked to original sources

PubMed2001

Diagnosis of equine piroplasmosis in Brazil by serodiagnostic methods with recombinant antigens.

Serum samples from horses in the States of Sao Paulo and Mato Grosso do Sul, Brazil were examined for diagnosis of equine piroplasmosis by both the latex agglutination test (LAT) and enzyme-linked immunosorbent assay (ELISA) with recombinant antigens. Of the 47 samples analyzed, 38 (81%) and 42 (90%) samples were positive for B. equi infection and B. caballi infection, respectively. In addition, 35 (75%) samples were positive for both B. equi and B. caballi infections. These results indicate that equine piroplasmosis is widespread and therefore a cause for serious concern in the States of Sao Paulo and Mato Grosso do Sul, Brazil.

Animals↗

PubMed2001

Reduction of the infectivity of Toxoplasma gondii and Eimeria stiedai sporozoites by treatment with bovine lactoferricin.

Sporozoites of Toxoplasma gondii preincubated with lactoferricin showed decreased activity in penetration of mouse embryonal cells. Mice inoculated with 10(5) sporozoites preincubated with lactoferricin showed a higher survival rate than those inoculated with the same number of untreated sporozoites. Likewise, sporozoites of Eimeria stiedai preincubated with lactoferricin also showed decreased activity in penetration of rabbit hepatobiliary cells. Rabbits inoculated with 10(5) sporozoites preincubated with lactoferricin shed fewer oocysts than those inoculated with the same number of untreated sporozoites. These results indicate that lactoferricin is effective to reduce the infectivity of sporozoites of Toxoplasma gondii and Eimeria stiedai.

Animals↗

PubMed2001

Detection of Cryptosporidium parvum oocysts in environmental water in Hokkaido, Japan.

Control of cryptosporidiosis is important in public health. Rivers that are polluted with Cryptosporidium and drinking water that is treated for drinking water production from polluted rivers could result in the waterborne disease of cryptosporidiosis. We carried out an epidemiological study of natural water supplies in Hokkaido, one of the largest dairy prefectures in Japan. To detect Cryptosporidium oocysts in environmental water, the filtration method was used for 28 samples, which were collected from 10 rivers. A method adapted from the United States Environmental Protection Agency (U.S. EPA) filtration method using a cartridge filter has been used for the collection of samples. Oocysts were separated from a pellet by discontinuous sucrose gradient method. Twelve samples were collected from 10 rivers and parasites were purified by iron (III) flocculation method. Cryptosporidium parvum oocysts were identified with the immunofluorescence antibody technique using DIF kit (Cellabs Pty. Ltd., Sydney/Australia). We detected Cryptosporidium oocysts in 6 out of 10 rivers sampled. Fifty percentage (14/28) of the samples were Cryptosporidium-positive. The average number of Cryptosporidium oocysts was 16.73/100 L (max. 80/100 L).

Animals↗

PubMed2001

Modified protection against Toxoplasma gondii lethal infection and brain cyst formation by vaccination with SAG2 and SRS1.

Numerous studies have supported the importance of immunity to SAG1, the most predominant antigen of Toxoplasma tachyzoite, in protection against Toxoplasma gondii infection. Nevertheless, vaccination with SAGI provides insufficient protection when compared with that of Toxoplasma lysate (TL). In order to screen the Toxoplasma antigens for immunogenic potential shown by modified protection or induction of specific immune response after infection, recombinant antigens were prepared in Eschericha coli using DNA fragments corresponding to SAG1, SAG2, SAG3, SRS1 and P54 of T. gondii RH strain maintained in our laboratory. Each of the recombinant antigen products or a mixture of the five antigens (Mix) was used to vaccinate mice. Mice then received a lethal dose of T. gondii. Up to 25% of the mice vaccinated with SAG2, SRS1, P54 and Mix survived, whereas there were no survivors in gene 10- (negative control), SAG1- and SAG3- vaccinated groups. In all the survivors, brain cysts were not observed. Conversely, vaccination with TL almost completely protected mice in the acute phase but permitted brain cyst formation and resulted in gradual decrease of survivors to 33% during 4 months of experiments. Western blot analysis on convalescent sera showed an extensive IgG induction to a 30 kDa antigen in TL-vaccinated mice, a 22 kDa in SAG2-vaccinated mice and a 55 kDa in P54-vaccinated mice. The protection modified by boost in specific antibody is suggestive of the immunogenic potential of SAG2, SRS1 and possibly P54 against T. gondii infection.

Animals↗

PubMed2001

Comparison of the growth inhibitory effects of canine IFN-alpha, -beta and -gamma on canine cells infected with Neospora caninum tachyzoites.

The growth inhibitory effects of recombinant canine interferon alpha (IFN-alpha), beta (IFN-beta) and gamma (IFN-gamma) were examined on Madin-Darby canine kidney cells infected with Neospora caninum tachyzoites. The parasite growth was inhibited by all IFNs in a dose-dependent manner. IFN-gamma inhibited the parasite growth with greater efficacy than IFN-alpha or IFN-beta. Moreover, the effect of IFNs on N. caninum growth associated with the suppression of the host cell viability. The present study indicates IFN-alpha and -beta, besides IFN-gamma, play a crucial role for N. caninum growth in host cells.

Animals↗

PubMed2001

Ontogeny of pig discrete Peyer's patches: expression of surface antigens.

Leukocyte populations present in the discrete Peyer's patches (PP) of the pig were characterized from birth (Day 0) to day 35 after birth by immunohistochemistry and image analysis. Immediately after birth, cell membrane expression of CD2 and CD3, major histocompatibilty complex (MHC) class 11 (both SLA (swine leukocyte antigen) -DQ+ and SLA-DR+), CD21, 74-22-15 and surface immunoglobulin (sIg) were all demonstrable. Computer assisted morphometric techniques were used to confirm the significant expansion of these cell populations from birth onwards. The distribution of the cell types was not random but suggested a preferential retention of cells at specific sites. This implies a degree of organization of immunological cells within the discrete PP, enhancing the potential to mount immune responses in the most efficient manner.

Animals↗

PubMed2001

Development of a polymerase chain reaction method for diagnosing Babesia gibsoni infection in dogs.

A pair of oligonucleotide primers were designed according to the nucleotide sequence of the P18 gene of Babesia gibsoni (B. gibsoni), NRCPD strain, and were used to detect parasite DNA from blood samples of B. gibsoni-infected dogs by polymerase chain reaction (PCR). PCR was specific for B. gibsoni since no amplification was detected with DNA from B. Canis or normal dog leucocytes. PCR was sensitive enough to detect parasite DNA from 2.5 microl of blood samples with a parasitemia of 0.000002%. PCR detected parasite DNA from 2 to 222 days post-infection in sequential blood samples derived from a dog experimentally infected with B. gibsoni. The detection of B. gibsoni DNA by PCR was much earlier than the detection of antibodies to B. gibsoni in blood samples by the indirect fluorescent antibody test (IFAT) or that of the parasite itself in Giemsa-stained thin blood smear film examined by microscopy. In addition, 28 field samples collected from dogs in Kansai area, Japan, were tested for B. gibsoni infection. Nine samples were positive in blood smears, 9 samples were positive by IFAT and 11 samples were positive for B. gibsoni DNA by PCR. The nucleotide sequences of PCR products from all 11 samples found positive by PCR were completely identical to that of the P18 gene of the B. gibsoni, NRCPD strain. These results suggest that PCR provides a useful diagnostic tool for the detection of B. gibsoni infection in dogs.

Animals↗

PubMed2001

Significant correlations of E-cadherin, catenin, and CD44 variant form expression with carcinoma cell differentiation and prognosis of extrahepatic bile duct carcinomas.

To clarify the relation between alteration of expression of cell adhesion molecules and progression of extrahepatic bile duct carcinomas. 55 cases were immunohistochemically examined for E-cadherin, alpha-catenin, beta-catenin, and CD44, with additional reverse transcription-polymerase chain reaction and Southern blotting hybridization (RT-PCR/SBH) assays. Levels of E-cadherin, alpha-catenin, and beta-catenin proteins were lower in carcinomas than in normal mucosa, while CD44 variants 3 and 6 were upregulated. Well-differentiated carcinoma showed higher expression of E-cadherin and alpha-catenin than moderately to poorly differentiated types. Macroscopically papillary lesions had higher expression of E-cadherin than their nonpapillary counterparts. RT-PCR/SBH for CD44 revealed the CD44 variant form to be more prevalent in carcinoma than in normal mucosa, correlating with the immunohistochemical results, and with more exon variety. The Cox proportional hazards test identified histologic type and E-cadherin expression as prognostic factors. Among the examined molecules, E-cadherin was especially related to papillary mass formation and a good prognosis.

Bile Duct Neoplasms↗

PubMed2001

Histological changes of thyroid tissues in patients with liver cirrhosis.

Alterations in thyroid hormone regulation and metabolism, such as low serum T3 and T4 with normal TSH, are frequently noted in liver cirrhosis, but few morphological studies have ever been done on thyroid tissue in liver cirrhosis. In this study we analyzed the histological changes of thyroid tissue in the patients with liver cirrhosis. Specimens of thyroid gland obtained from autopsies in 16 cirrhotic patients were examined, and compared with those of two control groups. Control group I consisted of 7 patients with diabetes mellitus and control group II, 12 patients who died from sudden onset of cardiovascular problems. We measured follicular diameter and epithelial width on light micrographs of the central portion of thyroid specimens. We graded the degree of colloid vacuole, lipofuscin deposition in follicular epithelia, regenerative reaction and perivascular fibrosis in 10 consecutive light microscopic fields of the specimen. In the cirrhotic group, mean follicular diameter and epithelial width were significantly shorter and thinner, respectively, than those in the two control groups. Perivascular fibrosis was more prominent in the cirrhosis group than in the controls. These findings suggest that thyroid glands in patients with liver cirrhosis have the characteristic features of hypoactivity.

Cardiovascular Diseases↗

PubMed2001

Characterization of phagocytic hemocytes in Ornithodoros moubata (Acari: Ixodidae).

Effects of fetal bovine serum (FBS) and complement on phagocytic activity in Ornithodaros moubata (Murray 1877) hemocytes and protease activity in the hemocytes were examined. At least three morphologically different cell types, granulocytes, plasmatocytes, and prohemocytes, were detected in hemolymph of O. moubata, and granulocytes and plasmatocytes showed phagocytic activity. FBS altered phagocytic activity of granulocytes, and complement affected phagocytic activity of plasmatocytes. Ticks were inoculated with fluorescent polystyrene beads in combination with FBS or complement. The average number of beads in granulocytes was significantly higher in the FBS injected group than the control (P < 0.01). The percentage of bead-ingesting plasmatocytes in complement inoculated ticks was significantly lower than that in heat-inactivated complement inoculated and control ticks (P < 0.05). Proteases of tick hemocytes localized in small granules in the cytoplasm not only in phagocytic hemocytes but also in prohemocytes. Results suggested modulation of tick hemocyte function through serum components, and digestion of phagocytosed foreign bodies in the hemocytes.

Animals↗

PubMed2001

Identification and the role of soluble antigens detected in bile from Eimeria stiedai-infected rabbits.

Antibodies against Eimeria stiedai sporozoites and merozoites were detected in the sera of rabbits immunized with bile obtained from infected rabbits on the 15th day post-infection. The trails made by gliding sporozoites were also detected by the sera. After penetration into the host cell, an antibody-binding region was observed on the parasitophorous vacuole membranes of the parasites. Rabbits administered a combination of the bile and cholera toxin shed fewer oocysts in the feces after infection than control rabbits. The immunized rabbits developed a high level of IgA antibody against soluble antigens in the bile. By immunoblotting, antigens with molecular masses of 32, 37, and 49 kDa were detected in the bile obtained from infected rabbits on the 15th day postinfection. Absorption treatment with sporozoites reduced or abolished the antibody reactivity to the 32-kDa antigen of merozoites and the bile antigens. However, antibody reactivity to the 37- and 49-kDa antigens still remained. These results indicate that soluble antigens are present in the bile of rabbits in the acute phase of infection, and these may be produced and released by merozoites during the host cell invasion process.

Animals↗

PubMed2001

Analysis of a growth-promoting factor for Babesia caballi cultivation.

Serum-free media were examined to culture Babesia caballi. Daigo's T (DT) basal medium supplemented with Daigo's GF21 (GF21) or GIT medium, which already contains GF21, supported the parasite propagation at 37 C in a humidified atmosphere under 5% CO2 in air. Growth of B. caballi was dependent of the suitable concentration (10-20%) of GF21. Therefore, GF21 was suggested as the growth-promoting factor for B. caballi. However, GIT medium did not support the growth of parasites from cryopreserved stabilates, and serum supplementation was essential for the retrieval of parasites.

Animals↗

PubMed2001

Isolation of Neospora caninum from the brain of a pregnant sheep.

Neospora caninum was isolated from the brain of a naturally infected pregnant sheep by inoculation of immunodeficient mice with a homogenate of the brain tissue. The ewe showed no clinical signs. Tachyzoites were observed in the tissues of the nu/nu mice injected with the brain tissue homogenate and the diagnosis was confirmed by immunohistochemical staining with anti-N. caninum antibodies and by detecting N. caninum-specific DNA by polymerase chain reaction.

Animals↗

PubMed2001

[Successful non-surgical treatment of acute coronary syndrome involving the left main coronary trunk in four elderly patients].

We encountered 4 patients aged over 80 with acute coronary syndrome involving the left main coronary trunk (LMT) who obtained a successful outcome by non-surgical management. CASE 1: An 80-year-old women suffered acute myocardial infarction. A coronary stent was placed at the orifice of the LMT for dilatation of severe 90% stenosis. Cardiac function was markedly improved after treatment during the chronic period. CASE 2: An 81-year-old man who developed non-sustained ventricular tachycardia. Coronary angiography demonstrated severe stenosis with haziness of the LMT. Intra-aortic balloon pumping was performed for one whole day after the attack and the follow-up study performed one month later revealed that the stenosis was markedly diminished to an insignificant grade without residual ischemia. CASE 3: An 81-year-old man developed acute inferior wall infarction with a background of severe triple vessel disease accompanied by an LMT lesion. Coronary stents were placed at three sites, i.e., the right coronary, LMT, and left anterior descending branch. Though initial treatment was successful, this patient died due to severe arrhythmia. Patients in who CABG is strongly indicated due to LMT lesion complicated with multiple organ disorders will increase as the population of the aged continues to increase in Japan. We obtained satisfactory results by intensive intense non-surgical management including PTCA. From our experience, adequate selection of therapeutic regimens for individual patients is important to improve the long-term prognosis as well as the immediate outcome in the acute stage.

Aged↗

PubMed2001

[Cardiovascular ultrasound: applications for the assessment of cardiac function].

Congestive heart failure(CHF) is usually associated with impaired left ventricular(LV) systolic function, and thus, the measurement of systolic function is an essential component of the evaluation of any patients with known or suspected cardiac disease. Among many parameters, most frequently used are LV percent fractional shortening and ejection fraction(EF), which can be easily measured from an M-mode echocardiogram. However, these M-mode measurements may be inaccurate in patients with asymmetrical LV due to myocardial infarction, right ventricular overload or sigmoid septum. Especially in such cases, EF should be measured using two-dimensional echocardiography. Usually, LV volumes and EF are calculated using the disc-summation method through the manual tracing of apical two-chamber and four-chamber echocardiograms. On the other hand, it has been recognized that congestive heart failure may arise in the absence of any systolic dysfunction and CHF due to systolic dysfunction never occurs in the absence of concomitant diastolic dysfunction. Although the analysis of pulsed-Doppler transmitral flow velocity has been most widely used for the noninvasive assessment of LV diastolic function, an increase in left atrial pressure during CHF can pseudonormalize an abnormal flow pattern and mask LV diastolic dysfunction. Recently, we proposed a new index for assessing LV diastolic function, flow propagation velocity, which can be measured with color M-mode Doppler echocardiography and baseline-shift technique. Recent studies have shown that the flow propagation velocity is a unique noninvasive parameter of LV diastolic function which can accurately detect the diastolic impairment in patients with different types of cardiac diseases with various loading conditions.

Diastole↗

PubMed2001

Clinical significance of noninvasive assessment of left ventricular diastolic function by Doppler echocardiography.

Transmitral flow velocity pattern obtained by the pulsed Doppler technique reflects left ventricular (LV) diastolic function, but an increase in left atrial pressure pseudonormalizes the flow pattern and masks diastolic dysfunction. We propose an index to assess LV diastolic function using color M-mode Doppler echocardiography and the base-line shift technique. This index, flow propagation velocity, represents the average velocity of early diastolic LV filling flow from the mitral orifice to mid-ventricle. In patients with ischemic heart disease and dilated cardiomyopathy including those with pseudonormalized transmitral flow pattern, flow propagation velocity had a good correlation with the time constant of early diastolic LV pressure decay (Tau), indicating that flow propagation velocity is a useful noninvasive parameter of diastolic function which does not pseudonormalize. We also found a significant correlation between flow propagation velocity and Tau in hypertrophic cardiomyopathy patients in contrast to inadequate or no correlation between each of the conventional parameters and Tau. In addition, our recent data suggest that flow propagation velocity was distinctly decreased even in the patients with hypertension who did not show significant increase in LV mass index. Flow propagation velocity is a unique noninvasive parameter of LV diastolic function, which can sensitively and accurately detect the diastolic impairment in patients with different types of cardiac diseases with various loading conditions.

Blood Flow Velocity↗

PubMed2001

[Ruptured cerebral aneurysm in childhood--report of two cases].

We report two pediatric patients with rupture of cerebral aneurysm developing subarachnoid hemorrhage. These two patients complained of headache and vomiting. Patient 1 was a 15-year-old girl. Cranial computed tomography (CT) showed a high density area in the left sylvian fissure, suggesting subarachnoid hemorrhage. Left carotid arteriography revealed an aneurysm at the left internal carotid artery bifurcation. Surgical pathology showed a saccular type aneurysm with disappearance of internal elastic membrane. Patient 2 was a 14-year-old girl. Cranial CT exhibited a high density area in the basal cistern and hematoma in the right frontal lobe, penetrating to the right lateral ventricle. Right carotid arteriography showed a right anterior cerebral aneurysm in the right anterior cerebral artery. Both patients underwent craniotomy and trapping successfully, and their subsequent clinical courses were uneventful.

Adolescent↗

PubMed2000

Predominance of canine parvovirus (CPV) in unvaccinated cat populations and emergence of new antigenic types of CPVs in cats.

Serological, sequence, and in vitro host range analyses of feline parvovirus (FPV) isolates in Vietnam and Taiwan revealed that more than 80% of the isolates were of the canine parvovirus (CPV) type, rather than feline panleukopenia virus (FPLV). Although parvovirus isolates from three Vietnamese leopard cats were genetically related to CPV type 2a or 2b, they had a natural mutation of VP2 residue 300 Gly to an Asp, resulting in remarkable changes in their antigenic properties. These results indicated the possibility that CPV-2a/2b-type viruses can spread in cats more efficiently than conventional FPLV under natural conditions and that CPV-2a/2b viruses are further evolving in cats.

Amino Acid Sequence↗