Biomedical subjects

Y Mimura

Publications and source records attributed to Y Mimura.

189 records · Page 11Linked to original sources

PubMedDate not supplied

Immune response to a hapten of fluorescein isothiocyanate in a single mouse analyzed by two-dimensional affinity electrophoresis.

Immune response to a hapten of fluorescein isothiocyanate (FITC) in a single BALB/c strain mouse was analyzed by two-dimensional affinity electrophoresis (2D-AEP). Anti-FITC antibodies were induced by immunization with FITC-conjugated bovine serum albumin. The antibodies were separated into a large number of spots of IgG due to differences in their isoelectric points(pI) and binding affinities to the FITC ligand. These spots consisted of IgG families which were composed of several spots having an identical affinity to the ligand but a different pI. The spots were not clearly detected in the antiserum taken on day 7 after the primary immunization, but on day 21 the spots of IgG were clearly detected, with a high diversity and specificity for the ligand. The size and number of IgG spots were markedly increased by the secondary immunization; however, the third immunization did not increase the size and number of IgG spots. The IgG spots of each family were specifically stained with an antimouse IgG subclass antibody. Furthermore, a monoclonal antibody (FL-D6) was separated by 2D-AEP into a single family which consisted of seven IgG1 spots having an identical affinity to FITC but different pIs. Therefore, each of the IgG families of anti-FITC antibodies in the antiserum can be generated by a single clone of anti-FITC antibody-producing cells. The substitution of dextran T2000 or lipopolysaccharide for bovine serum albumin as a carrier for FITC induced much smaller amounts of anti-FITC antibodies with a low diversity but high specificity to FITC.

Animals↗

PubMedDate not supplied

Ocular activity of topically administered anandamide in the rabbit.

Marijuana and its psychoactive constituents, cannabinoids, reduce intraocular pressure (IOP) in humans and animals. Because anandamide, a recently discovered endogenous ligand of cannabinoid receptors, reportedly shows cannabimimetic pharmacological activity, we examined its effect on the eye. Varying amounts of anandamide, in 50 microL of light mineral oil, were topically applied to a rabbit eye and changes in IOP and ocular symptoms were monitored. Anandamide (50 micrograms to 1 mg) induced a significant decrease in IOP within 1 hour after administration; maximum reduction occurred at 2 hours; and there was a return to baseline by 7 hours following administration. A noticeable hyperemia of conjunctival blood vessels was also noted 2 hours after administration. Neither mineral oil alone or with palmitylethanolamide (an analogue of anandamide) caused a significant decrease in IOP or conjunctival hyperemia. This study indicates that anandamide does produce cannabimimetic effect in rabbit eyes.

Administration, Topical↗

PubMedDate not supplied

The influence of glycosylation on the thermal stability and effector function expression of human IgG1-Fc: properties of a series of truncated glycoforms.

Antibodies are multifunctional molecules that following the formation of antibody antigen complexes, may activate mechanisms to effect the clearance and destruction of the antigen (pathogen). The IgG molecule is comprised of three globular protein moieties (2Fab+Fc) linked through a flexible hinge region. While the Fabs bind antigens, the Fc triggers effector mechanisms through interactions with specific ligands, e.g. cellular receptors (FcgammaR), and the C1 component of complement. Glycosylation of IgG-Fc has been shown to be essential for efficient activation of FcgammaR and C1. We report the generation of a series of truncated glycoforms of IgG-Fc, and the analysis of the contribution of the residual oligosaccharide to IgG-Fc function and thermal stability. Differential scanning microcalorimetry has been used to compare the stabilities of the homogeneous glycoforms of IgG1-Fc. The results show that all truncated oligosaccharides confer a degree of functional activity, and thermodynamic stability to the IgG1-Fc, in comparison with deglycosylated IgG1-Fc. The same truncated glycoforms of an intact IgG1 anti-MHC Class II antibody are shown to exhibit differential functional activity for FcgammaRI and C1 ligands, relative to deglycosylated IgG1. The minimal glycoform investigated had a trisaccharide attached to each heavy chain and can be expected to influence protein structure primarily in the proximity of the N-terminal region of the C(H)2 domain, implicated as a binding site for multiple effector ligands. These data provide a thermodynamic rationale for the modulation of antibody effector functions by different glycoforms.

Calorimetry, Differential Scanning↗

PubMedDate not supplied

para-Chlorophenylalanine induces lenticular opacities by prenatal, neonatal, and juvenile treatments, but not by adult treatment, in rats.

The lenticular opacities induced by the administration of para-chlorophenylalanine (PCPA) during the different developmental periods were investigated in rats. Rats were given PCPA (100 or 200 mg/kg) during prenatal, neonatal, juvenile, and adult periods, and their lenses were observed ophthalmologically. The prenatal treatment with PCPA on gestation days 14-20 (GD 14-20) produced lenticular opacities that were detected in the area of the lens nucleus (pin-head opacity), and the neonatal treatment on postnatal days 0-40 (PD 0-40) produced mature cataracts. The juvenile treatment on PD 14-40 produced opacities in the posterior area as early as the day following the first treatment (PD 15). When the administration was continued, mature cataract was developed. However, we did not detect any changes in the lens of the adult rat (over 11 weeks of age) treated with the same dose of PCPA. These results suggest that the incidence of a PCPA-induced cataract depends on the age of the animals when PCPA is administered.

Animals↗

PubMedDate not supplied

Inhibitory effect of aldosterone on the natriuretic response to atrial natriuretic peptide in hypocapnic rats.

UNLABELLED: 1. Previous studies have shown that acute hypocapnia blunts the natriuretic effect of atrial natriuretic peptide (ANP) independently of the renal nerves and that the effect of ANP is restored by total adrenalectomy. We investigated the natriuretic response to ANP in potassium canrenoate (aldosterone receptor antagonist)-treated rats to clarify whether aldosterone contributes to the attenuated natriuretic response to ANP during hypocapnia. 2. Wistar rats, challenged with either canrenoate or saline vehicle, were infused with 10 micrograms/kg per h ANP during acute hypocapnia achieved by mechanical ventilation. 3. In saline-treated hypocapnic rats, ANP infusion failed to increase the fractional excretion of sodium (FENa) (from 3.49 +/- 0.26 to 5.03 +/- 0.42%, respectively; n = 6) which was similar to values for time control rats (from 3.00 +/- 0.61 to 4.41 +/- 0.68%; n = 6). The hyporesponsiveness to ANP during hypocapnia was also evident when the FENa was compared with that of normocapnic rats (from 3.92 +/- 0.69 to 7.87 +/- 0.45%; P < 0.05; n = 6). In canrenoate-treated rats, ANP infusion caused greater increases in sodium excretion (FENA from 3.05 +/- 0.71 to 7.21 +/- 0.45%; P < 0.05; n = 8) than saline infusion (FENA from 4.16 +/- 1.11 to 5.47 +/- 0.66%; n = 6), despite the hypocapnia. The increase in FENA after ANP infusion during hypocapnia (4.16 +/- 0.86%) was similar to the increase seen during normocapnia (3.89 +/- 0.86%; n = 9). 4. IN CONCLUSION: (i) acute hypocapnia blunts the natriuretic effects of ANP; and (ii) this attenuation is restored by potassium canrenoate treatment. The data suggest that aldosterone plays an important role by limiting the renal actions of ANP during acute hypocapnia.

Aldosterone↗

PubMedDate not supplied

VL thalamotomy for the treatment of tremor in patients with thalamic syndrome.

A 59-year-old female who underwent successful thalamotomy for tremor in thalamic syndrome was reported. Thalamic syndrome including tremor of the left limbs and slight dysesthesia over the left side of the face was thought to be due to the vascular lesion located in the right thalamus and adjacent structure by detailed radiological and electrophysiological examination. Significant alleviation of tremor was achieved by right VL thalamotomy without any complication.

Brain Diseases↗

PubMedDate not supplied

Numerical aberrations of chromosome 17 detected by FISH with DNA-specific probe in oral tumors.

Numerical aberrations of chromosomes were investigated in oral tumors by using fluorescence in situ hybridization (F1SH) with 4 chromosome centromere-specific DNA probes. The hybridization signals of the centromere sequence were easily detected and counted within interphase nuclei as well as metaphase chromosomes. The number of hybridized signals for chromosome 17 significantly increased in oral malignant tumors compared to benign tumors, which had two spots as well as normal lymphocytes. Cell lines derived from oral squamous cell carcinoma also showed numerical aberrations of chromosomes 1, 4 and 11, in addition to chromosome 17. These findings suggested that numerical aberrations of chromosomes occur during the development of malignant tumors of the oral cavity.

Carcinoma, Squamous Cell↗

PubMedDate not supplied

Biliary secretion of endotoxin and pathogenesis of primary biliary cirrhosis.

Previous studies suggested endotoxin, derived from the intestine through the portal blood to the liver, was predominantly metabolized by Kupffer cells. In the present study, fluorescent-labeled endotoxin injected into the rat portal vein was demonstrated not only in Kupffer cells but also in hepatocytes. Furthermore a great amount of labeled endotoxin was recovered in bile. In the livers of patients with primary biliary cirrhosis (PBC), immunohistochemistry demonstrated significant retention of endotoxin in the biliary epithelial cells, and treatment with ursodeoxycholic acid significantly reduced the retention in those cells. The study for detection of apoptosis demonstrated increased rates of apoptosis in hepatocytes and biliary epithelial cells in PBC liver, and the rate of apoptosis in biliary epithelial cells was significantly reduced after treatment with ursodeoxycholic acid. Immunohistochemistry in PBC liver demonstrated significant reduction of fluorescence intensity for a 7H6 antigen in biliary epithelial cells, indicating the increased paracellular permeability of bile ducts, because cellular immunolocalization of that antigen has been shown to be inversely correlated with the paracellular permeability of the tight junction. These results suggest that, in biliary epithelial cells, retention of endotoxin, increased apoptosis, and increased permeability of tight junctions may be involved in the pathogenesis of PBC.

Animals↗

PubMedDate not supplied

Morphologic studies on the biologic seal of titanium dental implants. Report II. In vivo study on the defending mechanism of epithelial adhesions/attachment against invasive factors.

Clinical measurements on gingival indices and morphologic observations were performed in this study to verify the defending mechanism of gingival soft tissue against foreign invasions from the perspective of epithelial adhesion/attachment to implant surfaces in the monkey mandible. The following zones were observed using scanning electron microscopy: (1) plaque zone, suggesting susceptibility of the gingival tissue to bacterial invasion; (2) nude zone, demonstrating indirect adhesion of epithelial cells to the implant surface through the mucous layer and preventing bacterial invasion; and (3) epithelial cell attached zone, having greater bond strength of epithelial cells at the cell-implant interface as compared to cell-cell bonding within the epithelial cell layer. This study suggested that epithelial cell attachment/adhesion may play a dominant role in retaining the successful condition of a dental implant.

Animals↗