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Biomedical subjects

Y Yokomizo

Publications and source records attributed to Y Yokomizo.

At least 73 records · Page 4Linked to original sources
PubMed1996

Suppressive effect of bronchoalveolar lavage fluid from pigs infected with Mycoplasma hyopneumoniae on chemiluminescence of porcine peripheral neutrophils.

Bronchoalveolar lavage fluid (BALF) from pigs experimentally infected with Mycoplasma hyopneumoniae suppressed the chemiluminescence (CL) response of porcine polymorphonuclear neutrophils (PMN). The suppressive effect was significantly correlated with the concentration of prostaglandin E2 (PGE2) in the BALF. Furthermore, purified human PGE2 suppressed the CL response of porcine PMN. The increased level of PGE2 following infection with M. hyopneumoniae may be responsible for the suppression of PMN function in the airway of infected pigs. The decrease of PMN function may be responsible for exacerbation of mycoplasmal pneumonia by secondary infection with pulmonary bacterial pathogens.

Animals↗
PubMed1996

Relationship of acid phosphatase activity to ultrastructural features in mice inoculated with Mycobacterium paratuberculosis.

Macrophage activation, measured as increased acid phosphatase (AcPase)-positive areas by image analysis, and ultrastructural features were examined in granulomatous mycobacterial lesions of mice innately susceptible (BALB/c mice; Bcg) and innately resistant (C3H/HeJ mice; Bcg) to Mycobacterium paratuberculosis strain ATCC 19698. In the liver and spleen of BALB/c mice 3 weeks after intraperitoneal inoculation with M. paratuberculosis, AcPase activity detected in epithelioid cell nodules was high; it had decreased, however, in the liver and spleen after a further 3 and 6 weeks, respectively. In C3H/HeJ mice, the size of epithelioid cell nodules in the liver and spleen was smaller than in BALB/c mice, and infiltrating macrophages, which had increased by week 9 after inoculation, showed high AcPase activity. Ultrastructurally, by week 32 in BALB/c mice, small phagolysosomes (SPLs) had greatly increased in number in the epithelioid cells. These SPLs contained a few AcPase-positive areas and a small number of bacteria, most of which were surrounded by an electron-translucent space (or electron-transparent zone [ETZ]). In contrast, only a few SPLs were observed in C3H/HeJ mice at week 32; in the liver and spleen, large phagolysosomes (LPLs) showed high AcPase activity and contained many degenerated bacteria, which also had an ETZ. These results suggest that the enzymatic and ultrastructural differences in phagolysosomes between BALB/c mice and C3H/HeJ mice reflect the susceptibility of these mouse strains to M. paratuberculosis.

Acid Phosphatase↗
PubMed1996

Effects of phospholipids on the in vitro percutaneous penetration of prednisolone and analysis of mechanism by using attenuated total reflectance-Fourier transform infrared spectroscopy.

We investigated the effects of 10 phospholipids on the in vitro percutaneous penetration of prednisolone (PR) through the dorsal skin of guinea pigs. A marked enhancing effect of PR penetration was observed in the presence of phospholipids that have unsaturated acyl chains. A maximum of 68-fold enhancement was observed compared to that of control. On the contrary, phospholipids that have saturated acyl chains did not significantly increase the amount of PR passing to the receptor side. Attenuated total reflectance-Fourier transform infrared spectroscopy was used to monitor the outer several microns of stratum corneum (SC) surface. It was observed that phospholipids that have unsaturated acyl chains induced higher and broader absorbance shifts in the C-H bond stretching region while phospholipids that have saturated acyl chains induced lower and sharper absorbance shifts in the C-H bond stretching region. A significant parallel between the amount of PR penetrated and the lipid-chain fluidity of the SC was found. These results suggest that phospholipids may influence the percutaneous penetration of PR by changing the lipid-chain fluidity of the SC.

Animals↗
PubMed1996

Intracellular survival and replication of Erysipelothrix rhusiopathiae within murine macrophages: failure of induction of the oxidative burst of macrophages.

We investigated the ability of a virulent wild-type parent strain and acapsular avirulent transposon mutants to enter and survive intracellularly within murine peritoneal macrophages. In the presence of normal or immune serum, the parent and mutant strains were both ingested; however, the number of ingested bacteria was three- to fourfold greater in the case of mutant strains than in the case of the parent strain. The parent strain, but not the mutant strains, survived and replicated intracellularly when ingested in the presence of normal serum, whereas both the parent and the mutant strains were readily killed when ingested in the presence of immune serum. To further investigate the mechanism by which the parent strain can survive and replicate within macrophages, we studied the oxidative burst response of macrophages to these strains by measuring chemiluminescence and intracellular reduction of Nitro Blue Tetrazolium dye. Challenge exposure of macrophages with either the parent strain preopsonized with immune serum or the mutant strains preopsonized with normal or immune serum induced a strong oxidative burst, whereas the level was very low when the parent strain was preopsonized with normal serum. Phagocytosis of either the parent strain, in the presence of immune serum, or the mutant strains, in the presence of normal or immune serum, by macrophages reduced large amounts of intracellular Nitro Blue Tetrazolium, whereas minimal amounts were reduced by the parent strain in the presence of normal serum. These results suggest that virulent E. rhusiopathiae can survive and subsequently replicate within murine macrophages when ingested in the presence of normal serum and that the reduced production of reactive oxidative metabolites by macrophages may, in part, be responsible for this occurrence.

Animals↗
PubMed1995

Proliferative response and cytokine production of bovine peripheral blood mononuclear cells induced by the superantigens staphylococcal enterotoxins and toxic shock syndrome toxin-1.

The potential of staphylococcal enterotoxin A (SEA), B (SEB), C(SEC) and toxic shock syndrome toxin-1 (TSST-1) to act as superantigens by inducing polyclonal T-cell mitogenesis and cytokine production was tested on bovine peripheral blood mononuclear cells (PBMC). These four toxins were capable of inducing strong proliferative response of PBMC from calves over a broad dosage range (1 pg/ml to 1 microgram/ml) in vitro. The toxin-activated blast cells consisted of both CD4+ T-cells and CD8+ T-cells, but the T-cell proliferation depended upon the presence of monocytes. Treatment of monocytes with monoclonal antibody to major histocompatibility complex class II antigens substantially inhibited the toxin-induced T-cell proliferative response, but paraformaldehyde-fixation did not abrogate the accessory function. SEA, SEB, SEC and TSST-1, all induced the in vitro release of interleukin-2, interferon gamma and tumor necrosis factor alpha in a dose dependent manner. The results indicate that SEA, SEB, SEC and TSST-1 are capable of acting as superantigens by stimulating bovine T-cells as shown in the human and murine systems. The possible implications of these toxins in the immunopathogenesis of bovine mastitis caused by the infection with Staphylococcus aureus are discussed.

Animals↗
PubMed1995

Establishment of a bovine macrophage cell line from a fetal thymus.

A cell line, FBM-17, was established from a fetal bovine thymus and passaged for more than a year. Electron microscopic examination revealed that the cytoplasm contained many phagosomes and a significant amount of rough endoplasmic reticula. In addition, FBM-17 cells showed non-specific esterase, phagocytosis and surface expression of Fc receptors for IgG and classes I and II MHC antigens. These observations confirmed that this cell line had the morphologic and functional features as a macrophage. MHC expression markedly increased by treatment with recombinant bovine gamma-interferon, showing the cell line to be sensitive to bovine gamma-interferon and functional. These present results suggest that the FBM-17 is a functional bovine macrophage cell line. This line gamma-interferon, showing the cell line to be useful for clarification of roles of macrophages in immunoregulation in cattle.

Animals↗
PubMed1994

Detection of interleukin-6 and prostaglandin E2 in bronchoalveolar lavage fluids of pigs experimentally infected with Mycoplasma hyponeumoniae.

In this study, interleukin-6 (IL-6) and prostaglandin E2 (PGE2) were detected in the bronchoalveolar lavage fluids (BALF) from pigs experimentally infected with Mycoplasma hyopneumoniae. IL-6 was detected at 2 weeks post-inoculation (PI), and significantly increased levels of PGE2 were observed at 4 weeks PI. In the BALF collected from infected pigs at 4 weeks PI, the levels of IL-6 increased significantly in the pigs with pneumonic lesions. However, increased levels of PGE2 were observed in all the infected pigs.

Animals↗
PubMed1994

Histopathological and morphometrical comparison of granulomatous lesions in BALB/c and C3H/HeJ mice inoculated with Mycobacterium paratuberculosis.

Susceptibility to Mycobacterium paratuberculosis strain ATCC 19698 infection was compared histologically and morphometrically in BALB/c (Bcgs) and C3H/HeJ (Bcgr) mice. The granulomatous lesions, containing M. paratuberculosis, in the liver and spleen of BALB/c mice increased progressively until 32 weeks after intraperitoneal inoculation. In contrast, both the granulomatous lesions and number of bacteria decreased drastically in C3H/HeJ mice beginning at 6 weeks after inoculation. There were histological differences in granulomatous lesions between BALB/c and C3H/HeJ mice, indicating differing functional activity of cellular immunity. Intestinal lesions similar to those seen consistently in bovine paratuberculosis were observed first at 6 weeks after infection and later became disseminated widely, especially in BALB/c mice. Our results suggest that the innately susceptible BALB/c mice and the innately resistant C3H/HeJ mice may be useful and convenient models for further studies of immunoregulation and antimicrobial therapy of paratuberculosis.

Animals↗
PubMed1994

Presence of a capsule in Erysipelothrix rhusiopathiae and its relationship to virulence for mice.

Three avirulent insertional mutants of Erysipelothrix rhusiopathiae were obtained by the technique of transposon mutagenesis with the self-conjugative transposon Tn916. The interactions between murine polymorphonuclear leukocytes and parent and mutant strains were studied in vitro. In the presence of normal serum, the virulent parent strain was resistant to phagocytosis, whereas the avirulent mutant strains were efficiently phagocytosed. In the presence of immune serum, the parent and the mutant strains were both efficiently phagocytosed. Electron microscopic examination of the parent strain demonstrated the presence of a structure resembling a capsule which was absent on the mutant strains, suggesting that a capsule may be involved in virulence. This was confirmed in studies in which an avirulent mutant strain reverted to virulence following acquisition of a capsule when the transposon was lost by spontaneous excision. These results strongly suggest that virulence of E. rhusiopathiae is associated, at least in part, with resistance to phagocytosis by polymorphonuclear leukocytes and that this antiphagocytic ability of the bacterium results from its possession of a capsule.

Animals↗
PubMed1993

Increased levels of tumor necrosis factor and interleukin 1 in bronchoalveolar lavage fluids from pigs infected with Mycoplasma hyopneumoniae.

We examined the levels of tumor necrosis factor (TNF)-alpha and interleukin-1 (IL-1) in bronchoalveolar lavage fluids (BALF) from pigs experimentally infected with Mycoplasma hyopneumoniae using biological assays with WEHI-164 cells and D10.G4.1 cells, respectively. Increased TNF-alpha and IL-1 in BALF were found in infected pigs with gross and/or microscopic lesions. A time-course study suggested TNF-alpha and IL-1 to be persistently elevated in infected pigs. Their presence in BALF would thus appear to be associated with the development of pneumonic lesions in M. hyopneumoniae infected pigs.

Animals↗
PubMed1992

Impairment of macrophage function in Mongolian gerbils.

Chemiluminescence studies on superoxide generation by phagosomes using opsonized zymosan showed the highest fluorescence in murine splenic macrophages among four different kinds of splenic or peritoneal macrophages from mice or gerbils. Murine splenic macrophages phagocytized two to three times more latex particles than gerbil splenic macrophages, but peritoneal macrophages did not show a significant difference in phagocytic activity between mice and gerbils. Phagocytosis by macrophages was determined by a technique based on measurement of the release of hydrogen peroxide and myeloperoxidase from phagosomes using microspheres conjugated with 3-(p-hydroxyphenyl) propionic acid (HPPA-MS). HPPA is a substrate of lysosomal myeloperoxidase. The fluorescence of HPPA-HPPA-MS produced by phagocytized HPPA-MS was measured with an immunoreaction analysis system (IMRAS), and the enzyme activities of the four different kinds of peritoneal or splenic macrophages from mice and gerbils were compared. All four kinds of macrophages produced HPPA-HPPA-MS in their phagosomes during phagocytosis and murine splenic macrophages showed the highest level of enzyme activity.

Animals↗
PubMed1991

Suppressive effect of nonviable Mycobacterium paratuberculosis on the delayed-type hypersensitivity reaction to sheep erythrocytes in mice.

The effect of nonviable Mycobacterium paratuberculosis on the delayed-type hypersensitivity reaction to sheep erythrocytes (SRBC) in mice was evaluated by means of delayed-type footpad swelling. Intraperitoneal (i.p.) injection with nonviable M. paratuberculosis into mice from 28 days before to 1 day after immunization with SRBC resulted in a significant suppression of foot-pad swelling to SRBC. The suppressive effect could be transferred by i.p. injection of spleen cells or peritoneal exudate cells from mice which had been pre-treated with nonviable M. paratuberculosis into non-treated recipient mice. The suppressive effect of spleen cells was retained even after passing them through a nylon wool column. The suppressive effect of spleen cells was abolished by treatment with anti-Thy 1.2 monoclonal antibody plus complement or anti-Lyt 2.2 monoclonal antibody plus complement. However, treatment of spleen cells with anti-mouse gamma globulin antiserum plus complement or anti-Lyt 1.2 monoclonal antibody plus complement did not affect the suppressive effect of spleen cells. The suppression of footpad swelling to SRBC induced by pre-treatment with nonviable M. paratuberculosis could be reversed by i.p. administration of cyclophosphamide. Serum antibody response to SRBC in mice was not affected by pre-treatment with nonviable M. paratuberculosis. These findings indicate that T cells appear to be involved in the suppression of delayed-type hypersensitivity reaction to SRBC in mice by pre-treatment with nonviable M. paratuberculosis.

Animals↗
PubMed1991

Evaluation of enzyme-linked immunosorbent assay in comparison with complement fixation test for the diagnosis of subclinical paratuberculosis in cattle.

An enzyme-linked immunosorbent assay (ELISA) was evaluated and compared in parallel with the standard complement fixation test (CFT) for the diagnosis of bovine subclinical paratuberculosis. Bovine sera preabsorbed with the mixture of Mycobacterium phlei and kaolin suspension were assayed for antibody activities to the crude protoplasmic antigen of Mycobacterium paratuberculosis in the ELISA. ELISA antibody titer was expressed as ELISA antibody index (EAI) value: EAI = (At-An)/(Ap-An), where At, Ap and An are the absorbance values of a 1:200 dilution of unknown test sera, a 1:400 dilution of positive control serum, and a 1:200 dilution of negative control serum. An EAI of 0.6 or greater was established as a reasonable cutoff point for a positive antibody titer by ELISA. Of the 156 sera from cattle with subclinical M. paratuberculosis-infection, 106 (67.9%) were positive by ELISA and 41 (26.3%) by CFT. Of the 3,880 sera from cattle in the herds which had no history or evidence of paratuberculosis, 3,875 (99.9%) were negative by ELISA, and 3,787 (97.6%) by CFT. Positive ELISA titers were detectable 1 to 5 months earlier than positive CFT titers in experimentally infected cattle, and 7 to 10 months earlier in naturally infected cattle. These results indicate that the ELISA should replace the CFT as the routine test of choice for the diagnosis of bovine paratuberculosis.

Animals↗
PubMed1990

Relationship between glycemic control and orthostatic hypotension in type 2 diabetes mellitus--a survey by the Fukuoka Diabetes Clinic Group.

We examined the prevalence of orthostatic hypotension and its association with glycemic control, as assessed by hemoglobin A1 (HbA1) concentration, in type 2 diabetic patients. The prevalence of orthostatic hypotension in 886 diabetics who were referred to our study and in 587 diabetics who were not given any antihypertensive drugs was 7% and 6%, respectively. The relationship between orthostatic hypotension and HbA1 levels was evaluated only in subjects not receiving antihypertensive drugs, since antihypertensive agents might induce orthostatic hypotension. HbA1 levels were 11.0 +/- 2.1% in the diabetic patients with orthostatic hypotension, which was significantly higher than the HbA1 levels of 9.9 +/- 2.2% in the diabetic patients without orthostatic hypotension. Multivariate analysis also revealed that the association remained significant after adjustment for the treatment and duration of diabetes, age, sex and body mass index. These findings suggest that glycemic control contributes to the development of orthostatic hypotension in type 2 diabetic patients.

Analysis of Variance↗
PubMed1989

Diuretics and other antihypertensive drugs and glycemic control in non-insulin-dependent diabetics with hypertension. A survey by the Fukuoka Diabetes Clinic Group.

We compared the levels of fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA1) in non-insulin-dependent diabetics with hypertension who were treated with monotherapy of diuretics or other antihypertensive drugs (AHD) and in those who were not given any AHD. Total 162 patients were divided into the four groups; the control group without AHD (n = 45), the diuretics group (n = 42), the beta-blocker group (n = 30) and the Ca-antagonist group (n = 45). FPG and HbA1 levels were 153 +/- 44 mg/dl and 10.0 +/- 2.3% for the control group, 145 +/- 55 mg/dl and 9.8 +/- 2.2% for the diuretics, 165 +/- 63 mg/dl and 10.2 +/- 2.1% for the beta-blocker and 158 +/- 42 mg/dl and 10.4 +/- 2.0% for the Ca-antagonist, respectively. There were no significant differences in the levels of FPG and HbA1 among the four groups. Multivariate analysis also revealed no difference in glycemic control even when anti-diabetic treatment (diet alone, oral hypoglycemic agents or insulin), body mass index, serum potassium, systolic and diastolic blood pressures and age were taken into account. Blood pressure levels did not differ among the groups except control and they were well controlled at the low doses of AHD. Our results suggest that the choice of low dose diuretics for the treatment of hypertension in non-insulin-dependent diabetics might not be necessarily excluded by the only reason of the possible deleterious influence on glycemic control.

Adrenergic beta-Antagonists↗