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Biomedical subjects

Y Hamaguchi

Publications and source records attributed to Y Hamaguchi.

At least 109 records · Page 6Linked to original sources
PubMed1989

Relationship between antigen levels in middle ear and antigen passage through round window membrane in antigen-induced otitis media.

By using an antigen-induced (Arthus) otitis media (OM) model in chinchillas sensitized with human serum albumin (HSA), we investigated the passage of HSA through the round window membrane (RWM) by measuring HSA levels in both the middle ear fluid (MEF) and the perilymph (PL). The effect of corticosteroid treatment on HSA passage was also studied. Mean HSA levels in both the MEF and the PL were proportional to the HSA dose administered (0.5, 5, 50 mg/ml). The proportion of HSA-positive PL samples was significantly lower in the sensitized group than that of the control (p less than 0.01). HSA levels in the PL appear to depend on HSA levels in the MEF, which were significantly depressed in the sensitized animals. These results suggest that an immunological reaction may be involved in the reduction of antigen (HSA) passage through the RWM by reducing antigen concentrations in the MEF. Corticosteroid treatment reduces the passage of HSA into the PL in non-sensitized animals.

Animals↗
PubMed1988

Accumulation of fluorescently labeled actin in the cortical layer in sea urchin eggs after fertilization.

Actin from sea urchin eggs was fluorescently labeled with fluorescein isothiocyanate (FITC), N-(7-dimethylamino-4-methylcoumarinyl)-maleimide (DACM), or 5-iodoacetamidofluorescein (IAF) and microinjected into sea urchin eggs and oocytes. It distributed evenly in the cytoplasm of unfertilized eggs. Upon fertilization, actin accumulated first around the sperm binding site and, soon afterwards, in the fertilization cone. The accumulation propagated all over the cortex after a latent period of 10-20 sec. In the case of Clypeaster japonicus eggs, propagation of the accumulation coincided with a shape change in the egg, suggesting that the accumulated actin in the cortex generates forces. FITC-actin was incorporated into microvilli and retained in the cortex after cleavage. On the other hand, DACM- or IAF-actin was not incorporated into microvilli and was dispersed from the cortex by cleavage. These differences may be attributable to differences in the properties of the actins labeled at different sites. After photobleaching by laser light irradiation, FITC- or IAF-actin redistributed in the cortex of fertilized egg as quickly as it did before fertilization. When an unfertilized egg was injected with both actin and a calcium buffer (intracellular free Ca2+ concentration 9 microM), the actin accumulation was similar to that during fertilization but without the latent period. This suggests that the accumulation depended on the increase in the intracellular free Ca2+ concentration. When the unfertilized egg was injected with 0.2 M EGTA after injection of labeled actin and then inseminated, it accumulated only in the protrusion of cytoplasm where the sperm had entered, and fertilization was not completed. In immature oocytes, the accumulation was observed in the cortical region, including the huge protrusion of the cytoplasm where the sperm had entered. These results suggest that actin accumulation in the sperm binding site plays an important role in the sperm reception mechanism of the egg.

Actins↗
PubMed1988

Micromanipulation studies of the asymmetric positioning of the maturation spindle in Chaetopterus sp. oocytes: I. Anchorage of the spindle to the cortex and migration of a displaced spindle.

We investigated the nature of the asymmetric positioning and attachment of Chaetopterus oocyte meiotic spindles to the animal pole cortex by micromanipulation. The manipulated spindle's behavior was analyzed in clarified oocyte fragments using video-enhanced polarized light microscopy. As the spindle was drawn towards the cell interior with a microneedle, the cell surface dimpled inwards adjacent to the outer spindle pole. As the spindle was pulled further inwards, the dimple suddenly receded indicating a rupture of a mechanical link between the cell cortex and outer spindle pole. The spindle paused briefly when released from the microneedle; then it spontaneously migrated back to the original attachment site and reassociated with the cell cortex. Positive birefringent astral fibers were seen running between the outer spindle pole and the cortex during the migration. The velocity of the spindle during its migration tended to increase as it came closer to the cortex. Velocities as high as 1.25 micron/sec. were measured. If removed too far from the attachment site cortex (greater than 35 micron), the spindle remained stationary until pushed closer to the original attachment site. Spindles, inverted by micromanipulation, migrated and reattached to the cortical site by their former inner pole; thus either spindle pole can seek out and migrate to the original attachment site. However, spindle poles pushed against other cortical regions did not attach demonstrating that there is only one unique, localized attachment site for spindle attachment.

Animals↗
PubMed1988

The relationship between antigen levels and middle ear inflammation in antigen-induced otitis media in the chinchilla.

The relationship between antigen levels in middle ear effusions (MEE) and the degree of middle ear inflammation was studied in an antigen-induced otitis media model, using chinchillas sensitized with human serum albumin (HSA). The degree of middle ear inflammation was evaluated by both tympanometric analysis, and cytological and biochemical analyses of the MEE. Middle ear inflammation develops after HSA challenge with a remarkable decrease in HSA levels in the MEE. This inflammation persists even when HSA levels are no longer detectable in the MEE. These findings show that local challenges with an antigen induce a certain degree of middle ear inflammation, which continues even after complete elimination of the antigen from the middle ear through an immunological defense mechanism.

Acoustic Impedance Tests↗
PubMed1988

Biochemical and cytological studies of immune-complex-induced otitis media in the chinchilla.

The pathogenesis of immune complex (IC)-induced otitis media in the chinchilla was studied through cytological and biochemical analyses of middle ear fluid (MEF) recovered after instillation of premade IC. The number to total leukocytes was 3.03 +/- 2.13 X 10(6)/cm3, and mainly involved neutrophils (72.3%) and macrophages (22.7%). The mean value of total protein, alpha 1-antitrypsin (alpha 1-AT) and alpha 2-macroglobulin (alpha 2-M) was 27.1 mg/ml, 189.5 and 75.2 mg/dl. The number of leukocytes had a significant correlation with the levels of total protein, alpha 1-AT and alpha 2-M (P less than 0.01). The inflammatory reaction induced by premade IC is characterized by an increased vascular leakage and an infiltration of leukocytes into the locus. The percentage of macrophages in the total leukocytes was larger in IC-induced otitis media than that in antigen-induced otitis media. These findings suggest that cellular events in the early stage of IC-induced otitis media may be different from antigen-induced otitis media.

Animals↗
PubMed1988

Plasma cell leukaemia of non-producer type with missing light chain gene rearrangement.

A case of plasma cell leukaemia of non-producer type is described. The patient presented with typical clinical features of plasma cell myeloma, including multiple osteolytic lesions, hypercalcaemia, renal failure and reduced polyclonal immunoglobulins, except that M-component was not detected in either the serum or urine. Morphological examinations showed a plasmacytoid appearance of the neoplastic cells, while immunological studies failed to detect cytoplasmic immunoglobulin or secretory capacity. The surface phenotype of CD38+, PCA-1+, DR-, CD20-, CD24-, CD9-, CD10- and surface immunoglobulin- was compatible with mature plasma cells. Chromosomal analysis showed the 14q+ marker due to translocation (6;14) and deletion of the short arm of chromosome 1. Analysis of immunoglobulin genes revealed the presence of heavy chain gene rearrangement, but the light chain genes, both kappa and lambda, remained in germline configuration. Such defective immunoglobulin gene rearrangement may be responsible for the failure of immunoglobulin biosynthesis and secretion by the neoplastic plasma cells. Furthermore, it is suggested that the morphological and phenotypic development of B cells may not necessarily depend on immunoglobulin light chain gene rearrangement, and that the oncogenic event in myeloma may occur at an earlier stage of B cell differentiation.

Chromosome Aberrations↗
PubMed1988

Interaction of bacteria with the immune system of Waldeyer's ring in otitis media with effusion.

An in vitro assay was used to study the adherence of Haemophilus influenzae (HI) to human nasal, nasopharyngeal, and buccal mucosal cells from patients with otitis media with effusion (OME). Adherence of unencapsulated HI was stronger than that of type b HI. HI adherence to both nasal and nasopharyngeal mucosal cells is stronger than that of buccal ones, indicating the presence of an important route of HI infection from the nose to the nasopharynx in OME. Specific antibodies against outer membrane vesicles (OMV) of HI were also examined using enzyme-linked immunosorbent assay. No significant correlation could be observed between specific secretory IgA or IgG titers and HI adherence to the nasopharyngeal mucosal cells, which suggests that HI adherence to the mucosal cells seems to depend on various factors including the local immunological defense system in OME patients. Anti-OMV IgA antibody producing cells were identified in the adenoid using the three-step immunoperoxidase method. These results suggest that non-typable strains of HI adhere more readily to epithelial cells and consequently are better suited to colonize the nasopharynx or to cause local infections.

Adolescent↗
PubMed1988

Introduction and expression of the interleukin 2 receptor (Tac) gene in hematopoietic stem cells with retrovirus vectors.

Retrovirus vectors provide an efficient carrier for introducing a gene into hematopoietic stem cells although expression of the inserted gene is not always successful. We constructed and compared three retrovirus vectors which carried cDNA encoding the light chain (Tac) of the interleukin 2 receptor under the control of different promoters; long terminal repeat (LTR) of murine retroviruses, the early promoter of simian virus 40 (SV40) and the promoter of the class I antigen gene of the major histocompatibility complex. We made three constructs containing these promoters. A first construct did not contain any additional promoter but LTR. A second and a third constructs contained the SV40 and the class I antigen gene promoters, respectively, in addition to LTR. The LTR of retrovirus vectors is derived from MoMuLV except that the U3 region of the 3'LTR of the third construct is derived from myeloproliferative sarcoma virus (MPSV). The second and third constructs were used for infection of bone marrow stem cells as the first construct was less efficient in expression of the interleukin 2 receptor in fibroblasts. Hematopoietic stem cells infected with the recombinant viruses were transplanted into lethally irradiated mice, and the expression of the transduced gene in hematopoietic progenitor cells was analyzed. Analysis of RNA isolated from spleen colonies showed that substantial amounts of interleukin 2 receptor mRNA were made by the construct containing the class I gene promoter and MPSV LTR. However, we could not detect any transcripts from the constructs containing MoMuLV LTR and SV40 early region promoter.

Animals↗
PubMed1988

[Infarct size related to the distribution and site of coronary artery lesions studied by the unfolded map technique using single photon emission computed tomography].

To assess the relative importance of the anatomical characteristics of the coronary artery distribution and the sites of the arterial stenoses in relation to infarct size, 21 patients with old myocardial infarction and angiographically-proven 90% or greater stenoses (AHA classification) of one of the major coronary arteries were studied. The infarct size was evaluated by a new quantitative method, the unfolded map, derived from single photon emission computed tomography (SPECT). Eleven patients had right coronary artery disease (Group RCA: segment 1; five patients and segment 2; six patients). Seven patients who had the large left anterior descending artery (LAD) which was distributed to the inferior portion of the apical area were defined as Small R, and four patients with large RCA as Large R. Ten patients each had a significant stenosis in the LAD (Group LAD: segment 6; six patients and segment 7; four patients). Four patients with significant stenosis proximal to segment 9 were defined as Pre-9, and seven patients with stenosis distal to the segment, as Post-9. Stress T1-201 scintigraphy with SPECT was performed and the unfolded map was obtained with data of the maximal count circumferential profiles in the redistribution image. Infarction was defined as a defect below 55% of the standard value. The necrotic area ratio expressed as percentage of the defect area to the entire map area was calculated and used as the indicator of infarct size. Although there was no significant difference in the necrotic area ratio between segment 1 and 2 lesions. Large R had the significantly larger necrotic area ratios (24.9 +- 4.6%) than did Small R (9.7 +- 4.4%; p less than 0.01). In the Group LAD, there was no significant difference in the necrotic area ratio between segment 6 and 7 lesions, but Pre-9 had the larger ratio (30.4 +- 3.3%) than did Post-9 (15.4 +- 7.7%; p less than 0.01). These data suggest that the factors related to infarct size are either the distribution of the coronary arteries in the apical area in the Group RCA or the sites of the stenotic lesions relative to the branching portion of the first diagonal branch in the Group LAD.

Adult↗
PubMed1987

Acute promyelocytic leukemia with an intracerebral mass and meningeal involvement after treatment of non-Hodgkin's lymphoma.

After a 3-month leukopenic phase, a patient developed hematologic pictures of acute promyelocytic leukemia (APL). Treatment with chemotherapy and radiotherapy had been given 10 months previously for a non-Hodgkin's lymphoma (NHL) of diffuse large cell type arising in the Waldeyer's ring. A computed tomographic scan demonstrated a high density mass in the left frontal cerebrum, which was enhanced uniformly by the contrast material. Cytocentrifuge examination of cerebrospinal fluid also showed an excess of promyelocytes. From these observations, the mass was considered to be an infiltration of leukemic cells. The intracerebral mass and meningeal involvement were resolved concomitantly with a hematologic remission of APL after intrathecal injection of cytosine arabinoside and systemic combination chemotherapy. This is a particular case of APL previously undescribed, representing an unusual presentation with intracerebral APL mass as well as a rare posttherapeutic APL following NHL.

Adult↗
PubMed1987

Interleukin 4 as an essential factor for in vitro clonal growth of murine connective tissue-type mast cells.

We investigated the biological activity of IL-4 to murine connective tissue-type mast cells (CTMC). When purified peritoneal mast cells, typical CTMC, were incubated with pokeweed mitogen-stimulated spleen cell-conditioned medium (PWM-SCM) in methylcellulose, about one-fifth of mast cells showed clonal growth. Recombinant IL-4 alone did not stimulate the clonal growth, and purified IL-3 alone induced development of a small number of tiny clusters. In contrast, addition of IL-4 to IL-3 increased the number of clusters by a factor of 10. The number and size of clusters induced by the combination of IL-3 and IL-4 were comparable to those of mast cell clusters induced by PWM-SCM. The present results indicate that IL-4 is an essential factor for in vitro clonal growth of CTMC.

Animals↗
PubMed1987

Vascular permeability of the middle ear mucosa in otitis media with effusion.

Vascular permeability (VP) of the middle ear mucosa (MEM) in chronic otitis media with effusion (OME) was estimated in both pediatric and adult patients by calculating the middle ear effusion (MEE) to serum concentration ratios of albumin and of four protease inhibitors: alpha 1-antitrypsin (alpha 1-AT), alpha 1-antichymotrypsin (alpha 1-X), inter-alpha-trypsin inhibitor (I-alpha-I) and alpha 2-macroglobulin (alpha 2-M). The levels of albumin and alpha 1-AT in MEE were higher while those of I-alpha-I and alpha 2-M were lower than their serum levels in both adult serous and pediatric mucoid groups. There was a negative correlation between molecular weight and the mean value of the ratio (MEE/serum) of the four inhibitors in both serous (r = -0.989) and mucoid (r = -0.924) groups. Vascular permeability of the MEM seems to be variable in both serous and mucoid groups during middle ear inflammation. Selective leakage of proteins by molecular weight appears to occur in MEM. Our findings further indicate that a high level of the high-molecular-weight inhibitor alpha 2-M in MEE may be a significant index reflecting the remarkably enhanced VP of the MEM.

Adult↗
PubMed1987

Redistribution of fluorescently labeled tubulin in the mitotic apparatus of sand dollar eggs and the effects of taxol.

Fluorescently labeled tubulin was quickly incorporated into the mitotic apparatus when injected into a live sand dollar egg. After a rectangular area (1.6 X 16 microns) of the mitotic spindle was photobleached at metaphase or anaphase by the irradiation of a laser microbeam, redistribution of fluorescence was almost complete within 30 sec. The photobleached area did not change in shape during the redistribution. During the period of redistribution, the bleached area moved slightly toward the near pole at metaphase and anaphase (means: 1.6 and 1.8 micron/min, respectively). These results indicate that redistribution was not due to the exchange of tubulin subunits only at the ends of microtubules but to their rapid exchange at sites along the microtubules in the bleached region. Furthermore, treadmilling of tubulin molecules along with the spindle microtubules possibly occurred at the rate of 1.6 micron/min at metaphase. Birefringence of the mitotic apparatus increased with a large increase in both the number and length of astral rays shortly after taxol was injected. However, the microtubules did not all seem to elongate at the same rate but appeared to become equalized in length. Chromosome movement stopped within 60 sec after the injection. Centrospheres became large and the labeled tubulin already incorporated into the centrospheres was excluded from the enlarged centrospheres. Shortly after the labeled tubulin was injected following the injection of taxol, it accumulated in the peripheral region of the centrospheres, suggesting that microtubules first assembled at this region. Fluorescently labeled tubulin in the mitotic apparatus in the egg after injection of taxol was redistributed much more slowly after photobleaching than in uninjected eggs.

Alkaloids↗
PubMed1987

Suppression of adjuvant arthritis in rats by cholesterol.

Dietary cholesterol suppressed adjuvant arthritis, a chronic inflammatory disease, in rats, but did not significantly affect carrageenin edema, an acute inflammation. When rats were fed a high-cholesterol diet beginning 10 days before injection of adjuvant, the development of the adjuvant-induced arthritis was greatly suppressed. Cholesterol feeding prevented hypertrophy of the adrenal gland in arthritic rats, but had little influence on the serum corticosterone level. A significant positive correlation was observed between the adrenal weight and the severity of the arthritis. These findings suggest that the effect of cholesterol feeding is not due to increased adrenal sterol synthesis. Dietary cholesterol also prevented hypertrophy of the spleen, but had no effect on atrophy of the thymus in adjuvant-treated rats. Cholesterol-fed rats showed a significant decrease in the serum lipid peroxide level and a significant increase in the serum copper level. Adjuvant treatment not only enhanced hypercholesterolemia produced by cholesterol feeding, but also the level of free cholesterol in serum. These results suggest that dietary cholesterol may exert some effect on the immune response through changes in spleen and liver functions.

Adrenal Glands↗