Biomedical subjects

J Asai

Publications and source records attributed to J Asai.

At least 37 records · Page 2Linked to original sources

PubMed1997

[A case of spontaneous middle cerebral artery occlusion associated with a cerebral aneurysm angiographically disappearing after STA-MCA anastomosis].

We report a case of a rapidly growing cerebral aneurysm in the basal abnormal vascular network associated with spontaneous middle cerebral artery (MCA) occlusion. The aneurysm disappeared spontaneously shortly after performing STA-MCA anastomosis. A 54-year-old female was admitted to our hospital because of repeated attacks of right hemisensory disturbance and dysarthria. CT scan and MRI images showed the infarcted focus in the left parieto-occipital lobe. Bilateral MCAs were undetectable on MRI images. Cerebral angiography revealed that the bilateral MCAs were occluded in their proximal origin with basal abnormal vascular networks. The distal MCA branches were perfused via the vascular networks. A small aneurysm was detected in the distal portion of the left Heubner's artery. There were no abnormalities in the bilateral internal carotid arteries, the anterior cerebral arteries, and the basilar artery. The follow-up angiography performed 29 days after admission revealed a growing aneurysm with a diameter of 3 mm in the distal enhanced lesion consistent with the aneurysm observed in the angiography. An STA-MCA anastomosis was performed for improvement of cerebral misery perfusion. Single photon emission tomography (SPECT) performed 9 days after the bypass operation revealed improvement of cerebral blood flow in the left parieto-occipital lobe, and her TIA attacks disappeared. The aneurysm was undetected in the cerebral angiography performed 24 days after the bypass operation. Spontaneous MCA occlusion is a rare condition of chronic cerebrovascular occlusive diseases. Diagnostic criteria of the disease includes the MCA occlusions or stenosis with basal abnormal vascular networks. Usually the phenomenon is seen unilaterally, which differs from moyamoya disease. Diagnosis must exclude diseases caused by the etiologies such as those of arteriosclerotic origin. There have been 24 reported cases of spontaneous MCA occlusion including our case. Among them, 9 cases presented cerebral aneurysm located in abnormal vascular networks, and all the reported cases presented cerebral hemorrhage at their onset. The abnormal basal vascular network may be developed as collateral vessels to supply blood to the ischemic regions in this disease. An increased hemodynamic stress in the abnormal basal vascular network may produce a true aneurysm in the distal portion of the perforating arteries. STA-MCA anastomosis reduced the TIA attacks, but also decreased the hemodynamic stress on the abnormal basal vascular network and resulted in reduction in size or thrombosis of the aneurysm. STA-MCA anastomosis can be considered effective to treat cerebral aneurysms located in vessels with increased hemodynamic stress.

Arterial Occlusive Diseases↗

PubMed1997

Effect of histamine on human fibroblast in vitro.

The effects of histamine (CAS 51-45-6) on cell growth, collagen synthesis of fibroblasts derived from human foreskin, and on fibroblast-mediated collagen remodelling were studied. The cellmat DNA content was measured 2 days after human fibroblasts were plated at a split ratio of 1:10. Effect of histamine (10(-9)-10(-4) mol/l) on the increase of DNA content was not observed. Fibroblasts at confluence were cultured with histamine only, and with pyrilamine or cimetidine in addition to histamine for 2 h. Type I procollagen C-peptide in the medium was measured by enzyme immunoassay and was corrected by DNA content. Type I collagen synthesis was stimulated by histamine (10(-6)-10(-4) mol/l) and its stimulation was inhibited by cimetidine, but not by pyrilamine. Collagen solution containing fibroblast was incubated until gelation. It was incubated with histamine only, and with pyrilamine or cimetidine in addition to histamine. The gel contraction was stimulated by histamine (10(-4) mol/l) and its stimulation was inhibited by pyrilamine, but not by cimetidine. These facts suggests that histamine stimulates type I collagen synthesis of fibroblast and collagen remodeling via H2 and H1 receptors, respectively.

Cell Division↗

PubMed1997

Structure and function of the hemolymph node in rats.

Hemolymph nodes (HLs) are unique lymph nodes, in that their lymphatic sinuses contain numerous erythrocytes. In this study, we compared the internal structure and immunologic function of HLs with those of ordinary lymph nodes (OLs) and the spleen. Electron microscopy revealed erythrocytes passing through the walls of blood vessels in the intermediate sinus area (IMSA) of a HL between expanded endothelial cell junctions. However, no direct communication was found between lymphatic sinuses and blood vessels. Numerous carbon particles appeared in the IMSA of HLs on 5 days after intravenous carbon particle injection, while OLs lacked particle deposition. Immunohistochemical studies showed that lipopolysaccharide (LPS) reached the IMSA of HLs and extravasated into medullary cords 4 hours after intravenous LPS injection, resulting in the appearance of more IgM-stained lymphocytes in the IMSA of HLs than in that of OLs on day 5. The ability of organs to produce antibodies was determined by counting the number of plaque forming colonies after intravenous injection of sheep red blood cells (SRBC). The HLs antibody-producing ability was between that of OLs and the spleen. These results suggest that HLs possess functionally open blood vessels in the IMSA and their immunologic capability is between that of OLs and the spleen. These findings suggests that HLs are lymphoid organs that have characteristics between those of the OLs and the spleen, both ultrastructurally and functionally.

Animals↗

PubMed1996

The effects of ultraviolet A and reactive oxygen species on the mRNA expression of 72-kDa type IV collagenase and its tissue inhibitor in cultured human dermal fibroblasts.

The effects of ultraviolet A (UVA) radiation and reactive oxygen species (ROS), generated with a xanthine and xanthine oxidase (XOD) system, on collagen enzymatic degradation involving the matrix metalloproteinase (MMP) and its tissue inhibitor of metalloproteinase (TIMP) were investigated using cultured human dermal fibroblasts. Total RNA was isolated and subjected to Northern blot analysis using cDNA clones for human interstitial collagenase (MMP-1), 72-kDa type IV collagenase (MMP-2) and TIMP-2. UVA irradiation resulted in an increase in MMP-1 mRNA up to 2.3-fold, but did not stimulate MMP-2 or TIMP-2 mRNA expression. In contrast, ROS induced by the xanthine and XOD system resulted in a dose-related increase in the level of MMP-2 mRNA up to 2.1-fold and a decrease in the level of TIMP-2 mRNA by 49% in the same fibroblasts. Catalase, used as scavenger, essentially prevented the ROS-induced alterations in MMP-2 and TIMP-2 mRNA levels. These results suggest that ROS produced in the dermis may contribute to biological changes in the connective tissue matrix observed in photoaging skin by accelerating the MMP-2-related matrix degradation system.

Cells, Cultured↗

PubMed1996

Chronic active Epstein-Barr virus infection with giant coronary aneurysms.

Chronic active Epstein-Barr virus infection (CAEBV) is a nonfamilial syndrome that shows a specific immunodeficiency for the Epstein-Barr virus (EBV). Prolonged fever, hepatosplenomegaly, lymphadenopathy, and liver dysfunction were seen in CAEBV, but cardiac complications are rare. An autopsy case of CAEBV with giant coronary aneurysms and aortic aneurysms is reported. The patient was a 5-year-old Japanese girl. At autopsy, the heart weighed 110 g, and bilateral coronary aneurysms were found. Microscopic studies revealed lymphoid vasculitis of coronary arteries, coronary venules, and aortic arteries. Immunohistochemically, infiltrating small lymphocytes were positive for CD3, CD45RO(UCHL-1), CD43(DF-T1). The presence of EBV in most of these T lymphocytes was proven by in situ hybridization using an EBV-encoded RNA-1 (EBER1) probe. To the best of the author's knowledge, pathology of aneurysms caused by lymphoid vasculitis in CAEBV has not been reported until now.

Child, Preschool↗

PubMed1996

Pyothorax-associated lymphoma. An unusual case with biphenotypic character of T and B cells.

Pyothorax-associated lymphoma is known to develop in patients who received an artificial pneumothorax for pulmonary tuberculosis some 30 to 40 years previously. Such patients exhibit large, immunoblastic lymphoma cells and often have a B-cell phenotype. We present a patient with an artificial pneumothorax and such a late developing lymphoma but with the unique finding of aberrant T- and B-cell phenotypes. Southern blot hybridization using immunoglobulin gene JH and T-cell receptor beta chain receptors revealed germline configurations. Lymphomas developing in immunocompromised patients, such as those with acquired immunodeficiency syndrome, may show such unusual phenotypes. The unusual phenotypes found in this patient provide evidence that his pyothorax-associated lymphoma was related to an immunocompromised state.

Aged↗

PubMed1996

Crystallization of an R-form lipopolysaccharide from Klebsiella pneumoniae.

An R-form lipopolysaccharide (LPS) from Klebsiella pneumoniae strain LEN-111 (03-:K1-) formed crystals, whose shapes were elongated hexagonal plates, trapezoid plates, and rhomboid plates, and whose greatest dimensions were 3.1 x 0.8 microns, when it was suspended in 50 mM Tris buffer at pH 8.5 containing 5 mM MgCl2 and kept at 4 C for as long as 870 days. K. pneumoniae LEN-111 synthesized LPS molecules possessing incomplete repeating units of the O-antigenic polysaccharide portion besides the R-form LPS because of a leaky characteristic, but crystals consisted exclusively of the R-form LPS. Although the size of crystals was not large enough for X-ray analysis and limited crystallographic information was available, it was suggested that the crystals consist of hexagonal lattices with an alpha axis of 4.62 A and c axis of 79.8 +/- 2.6 A. The present results showed that R-form LPS lacking the O-antigenic polysaccharide portion tends to form crystals during long-term incubation in Tris buffer at pH 8.5 containing MgCl2 at 4 C.

Crystallography, X-Ray↗

PubMed1996

Effect of the hydroxyl radical on fibroblast-mediated collagen remodelling in vitro.

1. It has been reported that free radicals prevent wound healing. However, the mechanism of this effect is not yet clear. We attempted to clarify the influence of hydroxyl radicals on wound healing in vitro. 2. We used an ascorbate-copper ion system (ACS) to produce hydroxyl radicals in accordance with variables of time elapsed and concentration of copper ion. The effects of hydroxyl radical on fibroblast-mediated collagen remodelling, cell viability, the functions of fibroblasts and collagen fibrils were studied. 3. With a copper ion concentration of 100 mumol/L ACS significantly reduced contraction, while 10 mumol/L stimulated contraction. Hydrogen peroxide (H2O2) was employed in observing these findings. ACS did not influence cell viability, the expression of alpha 2 beta 1 integrin and cellular fibronectin, or the cytoskeletal organization of fibroblasts involving actin until 3 h. A concentration of ACS at 10 mumol/L of copper ion induced the polymerization of collagen after 30 min, while ACS at 100 mumol/L induced collagen degradation; this finding was also established by using H2O2. Collagen reduced the amount of formaldehyde produced by trapping hydroxyl radical with dimethyl sulfoxide. 4. Our findings suggest that collagen is denatured by scavenging the hydroxyl radical before fibroblasts are damaged, so that the radical may influence the remodelling of collagen.

Cell Survival↗

PubMed1996

Kinetics of monocytoid B lymphocytes in localized inflammatory lesions induced by lipopolysaccharide in mice.

Immunohistochemistry was used to study the kinetics of B lymphocytes (B-lys) in the early stages of the localized inflammatory response induced in SMA mice by the subcutaneous injection of lipopolysaccharide (LPS). At the injection sites, medium-sized B-lys formed early inflammatory lesions with neutrophils and activated macrophages on days 1 and 2. The B-lys were morphologically similar to monocytes, but were not stained with Mac1 antibody. Remarkably the B-lys showed the phenotypes of B220+, IgM+, IgD (slight to negative), Ly-1- and CD23- by double immunohistochemical staining. The B-lys were also positive for alkaline phosphatase. Consequently the B-lys could be identified as monocytoid B-lys or marginal zone B-lys. Plasmacytic B-lys and plasma cells were first observed on days 3 and 4, but no lymphoid follicles were found at the injection sites. In the inguinal lymph nodes, the same B-lys responses were mainly induced in the paracortical lesions (T cell areas) preceding the formation of activated germinal centers (GC). These findings suggested that the B-lys, induced by injections of LPS, matured into plasma cells in the localized inflammatory lesions independent of GC, and that they were different from follicular B-lys.

Animals↗

PubMed1996

Primary gastric lymphomas: morphologic, immunohistochemical and immunogenetic analyses.

Morphologic, immunohistochemical and immunogenetic studies were performed on 28 cases of primary gastric lymphoma from fresh frozen tissue. Eight cases were diagnosed as diffuse large B-cell lymphoma, four as follicular center lymphoma (follicular), five as mucosa-associated lymphoid tissue (MALT) lymphoma, three as plasmacytoma, and three as T-cell lymphoma, two as mantle cell lymphoma, one as follicular center lymphoma (diffuse, predominantly small cell), and one as lymphoplasmacytoid lymphoma, and one as Hodgkin's disease. From immunohistochemical studies, four types of morphologically similar low-grade lymphomas can be differentiated by a combination of various monoclonal antibodies. Cases of diffuse large B-cell lymphoma may have a germinal center origin. We observed lympho-epithelial lesions in cases of non-MALT lymphomas. We therefore consider that the current diagnostic criterion for MALT lymphoma may not always be valid. Except for cases of T-cell lymphoma and Hodgkin's disease, 17 out of 22 cases revealed clonal rearrangement bands of the JH gene. In situ hybridization (ISH) and polymerase chain reaction (PCR) studies revealed the presence of Epstein-Barr (EB) virus genomes in two and three cases, respectively. Epstein-Barr virus may play a role in lymphomagenesis, although on relatively rare occasions.

Genes, Viral↗

PubMed1996

Primary cardiac lymphoma. No evidence for an etiologic association with Epstein-Barr virus.

OBJECTIVES: To report two cases of primary cardiac lymphoma, a rare extranodal lymphoma with an unknown pathogenesis, and to compare them to secondary B-cell cardiac lymphoma. DESIGN: Clinicopathologic features are described, using histologic and immunophenotypic examinations. The Epstein-Barr virus genome is detected by in situ hybridization. PATIENTS: Of 80 autopsied cases of malignant lymphoma identified at Nagoya (Japan) University Hospital, two patients with primary cardiac lymphoma and five patients with secondary cardiac B-cell lymphoma were selected. RESULTS: None of the seven selected cases showed immunodeficiency, autoimmune disorders, or chronic inflammatory processes. Primary cardiac lymphomas had B-cell phenotypes with mu and lambda chain monoclonality. Immunostaining for Epstein-Barr virus (latent membrane protein-1) and Epstein-Barr virus-encoded RNA-1 in situ hybridization did not demonstrate an association of these lymphoma with Epstein-Barr virus infection. The majority of secondary cardiac B-cell lymphomas were extranodal lymphomas and extranodal or serosal involvement was more prominent than nodal involvement. CONCLUSION: These findings suggest that primary cardiac lymphoma, unlike pyothorax-associated pleural lymphoma, appears to have no association with chronic inflammation or Epstein-Barr virus infection.

Aged↗

PubMed1996

Expression of perforin in nasal lymphoma. Additional evidence of its natural killer cell derivation.

Eight patients with nasal lymphoma in whom fresh-frozen tissues were available were studied to elucidate the nature of the lymphoma cells. Two cases were diagnosed as diffuse, large cell lymphoma, and the remaining six cases as diffuse, mixed cell types. Immunohistochemical studies revealed that all of the cases were positive for perforin, which is a specific marker for cytotoxic T or natural killer (NK) cells. As all of the cases were CD8 negative, the perforin-positive finding further confirmed the concept that nasal lymphoma is a distinct neoplastic entity derived from NK or NK-related cells. Light microscopic immunohistochemical studies revealed that these nasal lymphoma cases could be classified into Leu19(CD56)+Leu4(CD3)+ (two cases) and Leu19(CD56)+Leu4(CD3)- (six cases) types according to the phenotypes of the proliferating cells. However, simultaneous staining for perforin and Leu4 (CD3) using immunoelectron microscopy on the Leu19+Leu4+ cases showed that the perforin-positive cells were different from the Leu4-positive cells. This finding suggests that the Leu4-positive cells are not neoplastic NK cells but reactive T cells. Six cases were positive for EBER-1 by in situ hybridization analysis. This finding reconfirms the previous studies that Epstein-Barr virus plays a significant role in the pathogenesis of nasal lymphoma.

Adult↗

PubMed1996

Poor correlation between clonal immunoglobulin gene rearrangement and immunoglobulin gene transcription in Hodgkin's disease.

It recently has been suggested that some cases of Hodgkin's disease (HD) are derived from B lymphocytes. We therefore examined immunoglobulin heavy chain gene rearrangement and transcription by polymerase chain reaction in 30 cases of HD and compared them with 25 cases of non-Hodgkin's B-cell lymphoma. Clonal VDJ gene rearrangements were observed in 6 cases of HD. Of these 6 cases, clonal VDJ gene transcription was found by RNA-dependent polymerase chain reaction in only 2 cases. One of these 2 cases histologically showed composite lymphoma of HD and diffuse large B cell lymphoma. We performed in situ hybridization with a clonal VDJ gene probe in this case to determine the localization of the genetic clonality. The large lymphoma cells reacted positively, but Hodgkin's and Reed-Sternberg cells showed only nonspecific staining. No discrepancy between immunoglobulin gene rearrangement and transcription was observed in 24 of the 25 cases of non-Hodgkin's B-cell lymphoma. The discordance between clonal gene rearrangement and transcription in HD contrasts sharply with the high correlation of those processes in non-Hodgkin's B-cell lymphoma.

Gene Rearrangement↗

PubMed1996

Evaluation of handling methods in the histological diagnosis of Helicobacter pylori: the effect of filter paper.

OBJECTIVES: Few studies have evaluated the handling methods used in the histological diagnosis of Helicobacter pylori. Filter paper has conventionally been used as a receptacle for the biopsy specimen before fixation. The aim of this study was to determine the presence of any effect caused by the use of filter paper. METHODS: The study population consisted of 104 consecutive patients undergoing endoscopic examination. Two antral biopsy specimens from the same area were obtained from each patient. One specimen was put onto a piece of filter paper, and the other into a plastic case. The specimens were fixed overnight in buffered formalin, embedded in paraffin, sectioned, and stained with hematoxylin and eosin and Giemsa. A direct smear was also prepared from 77 patients by vigorously rubbing the filter paper on a glass slide and staining it with Giemsa. RESULTS: The detection rate of H. pylori was 47.1% (49 of 104) for the filter paper method, 56.7% (59 of 104) for the plastic case method, and 57.7% (60 of 104) for either of the two methods. Of the 60 positive patients, 11 filter paper specimens were negative, whereas only one plastic case specimen was negative. Statistical analysis revealed a significant difference between the two groups (p < 0.01). On the amount of H. pylori, the filter paper method showed a significantly lower grade than the plastic case method (p < 0.05). In the Giemsa-stained smears, H. pylori was identified in 17 (22.1%) of the 77 patients studied. CONCLUSIONS: Use of filter paper may decrease the sensitivity for detection of H. pylori infection. We recommend not using filter paper in the histological diagnosis of H. pylori.

Biopsy↗

PubMed1995

Spatial and temporal expression of the ret proto-oncogene product in embryonic, infant and adult rat tissues.

Immunohistochemical analysis with the anti-Ret antibody was performed to investigate the expression of the c-ret proto-oncogene product (c-Ret protein) in embryonic, infant and adult rat tissues. During embryogenesis, the c-Ret expression became detectable by day 11.5 in the developing peripheral and central nervous systems as well as in the excretory system. In the peripheral nervous system of the trunk, it was expressed at high levels in the enteric neuroblasts and the autonomic and dorsal root ganglia. c-Ret positive cells appeared in the mesenchyme around the foregut and the dorsal aorta at day 11.5 and formed the myenteric plexus of the whole embryonic gut and the sympathetic trunk at later stages respectively. Examination of the cranial region revealed that the c-Ret protein was expressed in neural crest cells migrating from rhombomere 4 at day 11.5 and then became positive in the facial, glossopharyngeal and vagus cranial ganglia at day 12.5-13.5. After day 16.5 of gestation, the c-Ret expression was also observed in the trigeminal ganglion. In the central nervous system, the c-Ret protein was expressed in the neuroepithelial cells of the ventral neural tube (day 11.5-14.5), the motor neurons of the spinal cord (day 18.5) as well as in the embryonic neuroretina (day 18.5). In addition to the nervous system, the c-Ret expression was detected in the nephric duct (day 11.5), the ureteric bud (day 13.5) and the collecting ducts of the kidney (day 16.5). After birth, neurons in the nervous systems mentioned above continued to express the c-Ret protein at variable levels while no c-Ret expression was observed in the kidney of adult rats. Furthermore, the c-Ret expression was found in the acinar cells of the salivary gland, the epithelial cells of the thymus and the follicular dendritic cells of the spleen and lymph node in infant and adult rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1995

Basic fibroblast growth factor-heparan sulphate complex in the human dialysis-related amyloidosis.

A major constituent of the amyloid fibrils in dialysis-related amyloidosis is beta 2-microglobulin (beta 2-MG). Heparan sulphates (HS) co-localize with the amyloid fibrils and monocytes/macrophages are commonly found around amyloid deposits, but the role of HS in amyloidogenesis is not yet defined. HS have variable saccharide sequences and can interact specifically with basic fibroblast growth factor (bFGF), a potent chemotactic factor for the monocyte/macrophage. The present investigation was undertaken to look for a functional link between co-localized HS and the pathogenesis of dialysis-related amyloidosis. Using amyloid-enriched ligament, immunohistochemical localization was tested for beta 2-MG, endogenous bFGF, and bFGF-binding portions of HS. For the detection of bFGF-binding portions of HS, the ligament sections were incubated with exogenous bFGF and then with anti-bFGF antibody. The specificity of the interaction between bFGF and HS was established by confirming a concomitant loss of immunoreactivity during selective removal of HS with heparitinase. beta 2-MG, endogenous bFGF, and bFGF-binding portions of HS were detected between bundles of collagen. Endogenous bFGF and bFGF-binding portions of HS were not detected in more advanced amyloid lesions, whereas beta 2-MG and other portions of HS were detected. We propose that beta 2-MG, endogenous bFGF, and bFGF-binding portions of HS form a complex and localize in the early amyloid lesions of dialysis-related amyloidosis.

Amyloidosis↗

PubMed1995

Immunohistochemical characteristics of chicken spleen ellipsoids using newly established monoclonal antibodies.

Ellipsoids, the extra-vasculature sites surrounding penicilliary capillaries of the chicken spleen, play critical roles in the immune response and also in the clearance of pathogens or other particles. The meshwork of ellipsoids is formed by fibroblastic reticular cells. To characterize ellipsoidal reticular cells, a series of monoclonal antibodies against the chicken spleen have been developed. Of these antibodies, CSA-1 antibody reacts with fibroblastic reticular cells in ellipsoids and with endothelial cells. The reticular nature of positive cells in ellipsoids is indicated by immuno-electron microscopy, and by double staining with anti-heat-shock protein 47 kDa (hsp47) antibody. The reaction of CSA-1 with reticular cells is limited in ellipsoids; CSA-1 does not react with reticular cells in other lymphoid organs. These findings indicate that ellipsoidal reticular cells share the antigen with endothelial cells. Ontogenic studies reveal that, on embryonic day 18, the development of ellipsoids is completed, penicilliary capillaries become fenestrated, and CSA-1 expression in ellipsoids begins. These findings suggest that CSA-1 is expressed on the cell surface of ellipsoidal reticular cells once they are exposed to blood flow.

Animals↗

PubMed1995

Two phenotypically distinct B lymphocytes (IgMhighIgDlow and IgMlowIgDhigh) in chronic gastric ulcer in the rat.

We determined the kinetics and phenotypes of infiltrating B cells in gastric ulcer in the rat induced by gastric injection of acetic acid (day 0). Few B cells were found in the lesion in the early stages of ulceration. On day 40, two kinds of B cells with phenotypes of IgMhighIgDlowOX33 (CD45)+OX19 (CD5)- and IgMlowIgDhighOX33 (CD45)+OX19 (CD5)- were scattered in the granulation tissue of open ulcers, but not in the healed scar tissue. On day 180, those two kinds of B cells formed primary follicles in the granulation tissue of open ulcers, but were absent from the healed scar tissue. The IgMhighIgDlowOX33 (CD45)+OX19 (CD5)- B cell was considered to be identical to the marginal zone B cell of rat spleen. This phenotype of B cell might be associated with inflammatory process in chronic gastric ulcer.

Acetates↗