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H Sawada

Publications and source records attributed to H Sawada.

At least 181 records · Page 10Linked to original sources

Methylphenylpyridium ion (MPP+) enhances glutamate-induced cytotoxicity against dopaminergic neurons in cultured rat mesencephalon.

Parkinson's disease is characterized by chronic progression of dopaminergic neuronal death, the mechanism of which is still unknown. Although methyl-4-phenylpyridium ion (MPP+) or MPP(+)-like substance, that can reduce mitochondrial complex I activity, is supposed to be a causative agent for Parkinson's disease, it is difficult to explain the chronic neuronal degeneration for years. It is important to identify other putative agents capable of causing chronic cell death besides MPP+. We hypothesized that treatment with small doses of MPP+, not causing severe damage to dopaminergic neurons but merely reducing the activity of mitochondrial complex I, can be a model of Parkinson's disease, and that glutamate can be a putative agent causing chronic neuronal degeneration. Using primary culture of the rat mesencephalon, we investigated glutamate-induced cytotoxicity against dopaminergic and non-dopaminergic neurons with or without the pretreatment with MPP+. Brief exposure to glutamate showed similar cytotoxicity against both dopaminergic and non-dopaminergic neurons. An N-methyl-D-aspartate receptor antagonist completely blocked the glutamate-induced cytotoxicity against both dopaminergic and non-dopaminergic neurons. In the dopaminergic neurons, MPP+ caused cytotoxicity that was not blocked by co-administration of MK-801. After pretreatment with small doses of MPP+, sub-lethal doses of glutamate caused severe cell damage restricted to dopaminergic neurons, suggesting that MPP+ potentiates the glutamate-induced cytotoxicity only against dopaminergic neurons. As glutamate is putatively capable of causing cytotoxicity against dopaminergic neurons, the present findings might be important in considering the pathogenesis of dopaminergic neuronal degeneration and a possible therapeutic application of glutamate receptor antagonists in Parkinson's disease.

1-Methyl-4-phenylpyridinium↗

Substrate specificity of ascidian sperm trypsin-like proteases, spermosin and acrosin.

In order to investigate systematically the substrate or subsite specificity of two sperm proteases, acrosin and spermosin (a novel trypsin-like protease) of the ascidian, Halocynthia roretzi, the effects of peptidyl-argininals on the purified enzymes as well as on fertilization were examined. Among four benzyloxycarbonyl (Z)-Leu-X-argininals (X = Pro, Leu, Ser, and Gly), Z-Leu-Pro-argininal showed the strongest inhibition toward the spermosin activity. On the P3 site specificity, Val-Pro-argininal derivatives showed a stronger inhibition than a Leu-Pro-argininal derivative, suggesting the preference of Val rather than Leu residue at the P3 position. Similar results were obtained by analyzing the hydrolyzing activity of the fluorogenic peptide substrates: it hydrolyzed Boc-Val-Pro-Arg-4-methylcoumaryl-7-amide (MCA) most efficiently, and Boc-Asp(O-benzyl)-Pro-Arg-MCA was the next best substrate, but Gly-Pro-Arg (or Lys)-MCAs were hardly hydrolyzed. On the other hand, acrosin was found to prefer Leu or Pro residue rather than Gly or Ser residue at the P2 position as revealed by comparing the Ki values of peptidyl-argininals. Detailed kinetic analysis on the inhibitory abilities of peptidyl-argininals toward the purified enzymes and the ascidian fertilization suggested that both acrosin and spermosin are involved in ascidian fertilization.

Acrosin↗

Effect of total hepatic vascular exclusion during liver resection on hepatic ultrastructure.

The aim of this investigation was to observe ultrastructural changes in the liver in response to warm ischemia during liver surgery. In 11 noncirrhotic patients, hepatic resection was performed under total vascular exclusion (TVE). The mean duration of warm ischemia was 28 minutes (range 16-48 minutes). Three specimens were taken from each patient: before clamping, at the end of TVE, and after reperfusion. Biopsy specimens were studied by light microscopy and by transmission electron microscopy (EM). At the end of the ischemic phase sinusoids were collapsed with resultant loss of normal hepatic architecture. Morphological changes to hepatocytes included focal chromatin condensation at the nuclear margins, distended nuclear envelope, and swelling of both mitochondria and endoplasmic reticulum. After reperfusion these changes reversed. The phenomenon of sinusoidal and hepatocellular recovery after TVE was seen in all the cases of this study, irrespective of age, sex, disease, type and severity of surgical intervention, and duration of TVE. It can be concluded that TVE over a period of 48 minutes has no irreversible deleterious effects on the ultrastructure of the noncirrhotic liver.

Adult↗

Differential motility stimulation but not growth stimulation or adhesion of metastatic human colorectal carcinoma cells by target organ-derived liver sinusoidal endothelial cells.

Liver is the most common distant metastatic site for colorectal cancers and when blood-borne colorectal cancer cells reach the liver, they first encounter hepatic capillary and sinusoidal endothelial cells. Thus we studied differences between highly (HT-29LMM) and poorly (HT-29P) liver-metastatic sublines of human colorectal cancer cells by examining the interactions between tumor cells and liver microvessel endothelial cells. Using hepatic sinusoidal endothelial (HSE) and lung microvessel endothelial (MLE) cell-conditioned medium we measured the growth and motility stimulating activities released from these endothelial cells and adhesion of these cancer cells to the endothelial cells. Differences in the ability of HSE-conditioned medium (HSE-CM) or MLE-conditioned medium (MLE-CM) to stimulate HT-29 cell growth were not observed. There was a small but significant increase in the rate of adhesion of highly metastatic HT-29LMM cells to HSE cell monolayers than poorly metastatic HT-29P cells, but there was no difference in adhesion to MLE cell monolayers. HSE-CM stimulated the motility of highly metastatic colorectal cancer cells to a greater extent than the poorly metastatic cells. Motility-stimulating activity for the colorectal cancer cell lines was not detected in MLE-CM. The HSE-CM motility-stimulating activity for human HT-29 cells was not removed using antibodies against hepatocyte growth factor (HGF/SF), complement component C3 or laminin, indicating that it is not related to these known liver-derived motility factors. The results suggest that the ability of highly metastatic HT-29LMM colorectal cancer cells to colonize the liver is related to their ability to respond to liver sinusoidal endothelial cell-derived motility factors and to a lesser degree to adhere to liver sinusoidal endothelial cells.

Animals↗

Distribution of peptidergic nerve fibres in bullfrog lingual papillae demonstrated by a combination of double immunofluorescence labelling and a multiple dye filter.

Immunoreactivity of substance P, calcitonin gene-related peptide, vasoactive intestinal polypeptide, neuropeptide Y, and galanin is localized in nerve fibres distributed in the fungiform and filiform papillae of the tongue of the bullfrog, Rana catesbeiana. A combination of indirect double immunofluorescence labelling and a multiple dye filter system clearly demonstrated that all substance P fibres in the connective tissue core of the fungiform and filiform papillae, and within the rim of ciliated cells located on the top of the fungiform papillae showed coexistence with calcitonin gene-related peptide. A few fibres in the epithelial discs, which are located in the centre of the top of the fungiform papillae, showed the immunoreactivity of calcitonin gene-related peptide alone. There were no substance P fibres which showed coexistence with vasoactive intestinal polypeptide, galanin, and neuropeptide Y. In high magnification images, substance P and vasoactive intestinal polypeptide, and substance P and galanin fibres were recognized as two intertwined fibres within the same thin nerve bundle. No immunoreactivity of leucine- and methionine-enkephalins can be detected. These findings suggest that the chemoreceptor function of the bullfrog gustatory organ may be under the control of complicated peptidergic innervation.

Animals↗

Distribution of substance P and calcitonin gene-related peptide immunoreactive nerve fibers in the trachea of chronically hypoxic rats.

The distribution of substance P and calcitonin gene-related peptide immunoreactive nerve fibers in the trachea was compared between normoxic and chronically hypoxic rats (at 380 mm Hg for 10 weeks). In the normoxic trachea, the immunoreactivity to either peptide was seen in the nerve fibers in four principal locations: a) within and b) under the ciliated epithelium, c) within the smooth muscle bundles in the posterior wall, and d) in the connective tissue and around blood vessels in the lamina propria and submucosa. These immunoreactive fibers within the epithelium and smooth muscle bundles, in the connective tissue, and around blood vessels were thin and displayed some varicosities, and those under the epithelium appeared as thick nerve bundles. When the distribution and density of immunoreactive fibers were compared between normoxic and chronically hypoxic tracheas, there was a difference in number of substance P and calcitonin gene-related peptide immunoreactive fibers penetrating into the epithelium, although there was no difference in the other three locations. The mean number of substance P and calcitonin gene-related peptide immunoreactive intraepithelial fibers per section of the chronically hypoxic trachea was significantly increased. Because substance P and calcitonin gene-related peptide are predominant signal peptides of primary sensory neurons, the increase of substance P and calcitonin gene-related peptide immunoreactive fibers suggests that altered airway reflexes may be a feature of hypoxic adaptation.

Animals↗

Properties of 26S proteasome purified from rat skeletal muscles: comparison with those of 26S proteasome from the rat brain.

A ubiquitin/ATP-dependent proteolytic complex (26S proteasome) was highly purified from rat skeletal muscles and its enzymatic properties were compared with those of the brain 26S proteasome. The purified 26S proteasome comprises 22-110 kDa subunits characteristic of the typical 26S proteasome on the basis of SDS-PAGE. The two-dimensional PAGE (NEPHGE and SDS-PAGE) pattern revealed that the pI values and molecular masses of the muscle 26S proteasome subunits were similar but not identical to those of the subunits of 26S proteasome purified from the rat brain. The enzymatic properties of the muscle 26S proteasome were very similar to those of the brain enzyme in substrate specificity and inhibitor susceptibility. The specific activities of the muscle 26S proteasome toward three fluorogenic peptide substrates were indistinguishable from those of the brain enzyme.

Animals↗

Vitronectin in the cytoplasm of Leydig cells in the rat testis.

Vitronectin is a multifunctional protein present in serum and in extracellular matrices, but its localization has not been fully elucidated. In the present study, immunoblotting with anti-rat vitronectin antibody showed that rat testes contained vitronectin in both Triton-soluble and -insoluble fractions. Immunofluorescence microscopy demonstrated that this immunoreactivity was localized mainly in the interstitial Leydig cells. Occasionally vitronectin was shown in some spermatocytes and around blood vessels. Immunoelectron microscopy with nanogold probes showed that vitronectin was present in the cytoplasm of Leydig cells but not in the nucleus or in the mitochondria and probably not on the luminal side of the endoplasmic reticulum. In situ hybridization with synthetic oligonucleotides, however, showed that vitronectin mRNA was not present in Leydig cells, although a faint reaction was shown in spermatogonia and/or in early spermatocytes. This observation was supported by the results of reverse transcriptase polymerase chain reaction, which showed that vitronectin mRNA was not present in the Leydig cell fraction, whereas a band corresponding to vitronectin gene product was detected in the seminiferous tubule fraction. These results indicate that Leydig cells contain vitronectin but do not synthesize it. The source of vitronectin in Leydig cells seemed to be either spermatogenic cells or blood.

Animals↗

Phylogenetic analysis of Streptomyces spp. causing potato scab based on 16S rRNA sequences.

The complete 16S rRNA sequences of 12 strains of Streptomyces spp., including potato scab pathogens, were determined. Among the strains of Streptomyces scabies that were isolated from diverse geographical areas and differed in melanoid pigment production, either no difference or one difference in sequence was observed. The sequence of S. scabies was most similar to the sequences of Streptomyces diastatochromogenes, Streptomyces bottropensis, and Streptomyces neyagawaensis, which belong to the Diastatochromogenes group. The levels of similarity of the 16S rRNA sequences of Streptomyces acidiscabies and S. scabies were almost the same as the levels of similarity between S. acidiscabies and other Streptomyces strains. Streptomyces sp. strain 91-Sy-13, which was isolated in Japan from potato scab and belongs to a distinct species on the basis of phenotypic characteristics and DNA relatedness, exhibited lower levels of 16S rRNA sequence similarity with other potato scab pathogens, as well as other Streptomyces species. The phylogenetic tree constructed on the basis of 16S rRNA sequence data showed that the Streptomyces spp. that cause potato scab composed unique branches. The results of our phylogenetic analysis based on complete 16S rRNA sequences confirmed the lack of close relationships among Streptomyces spp. that cause potato scab. Our findings suggest that potato scab is caused by phylogenetically diverse Streptomyces species and that the pathogenicities of these organisms developed independently.

Base Sequence↗

Serial transplantation of adult T cell leukemia cells into severe combined immunodeficient mice.

The precise mechanism of the neoplastic cell growth of adult T cell leukemia (ATL) still remains unclear. In the present study, we have succeeded in serial transplantation of ATL cells from a patient into severe combined immunodeficient (SCID) mice. In this model, we found that only a leukemic cell clone from an ATL patient could be successively transplanted into SCID mice, although it was difficult to maintain leukemic cell clones in vitro, suggesting that the microenvironment provided by SCID mice is suitable for leukemic cell growth. We could not detect human T cell leukemia virus type I (HTLV-I) mRNA or interleukin 2 (IL-2) mRNA in either the tumor cells growing in mice or the original leukemic cells. Thus, it appears that neither HTLV-I viral expression nor the IL-2 autocrine mechanism is directly involved in the neoplastic cell growth of fresh ATL cells as well as HTLV-I-infected cell lines, at least in SCID mice. In addition, we could passage frozen cells and obtain a large number of expanded leukemic cells in this model. Such a serial transplantation model, which can avoid the changes in the nature of leukemic cells that are frequently observed in in vitro culture, and which can propagate leukemic cell clones, would be very suitable not only to study the mechanism of neoplastic cell growth, but also to test potential therapeutic agents for ATL.

Aged↗

Reduced activity of anabolizing enzymes in 5-fluorouracil-resistant human stomach cancer cells.

The mechanism of resistance to 5-fluorourcil (5-FU) was studied with NUGC-3/5FU/L, a human stomach cancer cell line which had acquired resistance as a consequence of repeated 5-day exposures to stepwise-increasing concentrations of 5-FU in vitro. NUGC-3/5FU/L was 200-fold and over 16-fold resistant to 96-h and 1-h exposures to 5-FU, respectively. NUGC-3/5FU/L incorporated less 5-FU into RNA, indicating resistance to the RNA-directed action of 5-FU. On the other hand, NUGC-3/5/5FU/L also showed resistance to in situ thymidylate synthase (TS) inhibition by 5-FU. Polymerase chain reaction-single-strand conformation polymorphism analysis of TS cDNA and a FdUMP ligand binding assay showed that quantitative and qualitative alterations of TS are not responsible for this resistance. In contrast, the ability to metabolize 5-FU to its active metabolites, FUTP and FdUMP, was reduced in NUGC-3/5FU/L. We found that not only the activities of uridine phosphorylase/kinase and orotate phosphoribosyl-transferase (OPRT), but also the level of phosphoribosyl pyrophosphate, a cosubstrate for OPRT, were significantly lower in NUGC-3/5FU/L than in the parent NUGC-3. These results indicated that resistance to 5-FU in NUGC-3/5FU/L is due to reduced activities of 5-FU-anabolizing enzymes, but not to an alteration of TS. 2'-Deoxyinosine effectively enhanced TS inhibition by 5-FU in the resistant cells, thus markedly sensitizing them to 5-FU.

Antimetabolites, Antineoplastic↗

Partial monosomy 10q and partial trisomy 9q with anal atresia due to maternal translocation: t(9;10)(q32;q26).

We report a case of a boy with a partial deletion of the long arm of chromosome 10 and partial duplication of the long arm of chromosome 9 due to maternal balanced translocation. The karyotype was 46,XY,-10, +der(10)t(9;10)(q32;q26)mat. Our patient had imperforate anus and as this finding is usually not observed in association with trisomy 9q, it suggests that partial monosomy of the long arm of chromosome 10 might be associated with anogenital anomalies.

Abnormalities, Multiple↗

Congenital chylothorax in a patient with 21 trisomy syndrome.

A female infant with 21 trisomy syndrome associated with congenital chylothorax was reported. She was born at a gestational age of 34 weeks by Cesarean section because of fetal hydrothorax and hydrops fetus, confirmed by ultrasonography at 32 weeks. Emergent resuscitation and immediate thoracentesis were performed soon after birth. After beginning breast feeding, the serous pleural fluid became opalescent and a diagnosis of congenital chylothorax was made. Feeding was changed to medium-chain triglyceride (MCT) feeding and the production of pleural effusion disappeared after thoracentesis was performed several times. Accumulating evidence suggested that MCT feeding and intermittent thoracentesis under echo guide were effective. Some reports on patients, including this one, suggest that there may be more patients with 21 trisomy associated with congenital hydrothorax. Therefore, congenital hydrothorax might be listed as a complication of 21 trisomy.

Chylothorax↗

The composition of wide-spaced collagen in normal and diseased Descemet's membrane.

Descemet's membrane, the specialised basement membrane of the corneal endothelium, contains a form of extracellular matrix described as wide-spaced collagen. In healthy human Descemet's membrane, wide-spaced collagen forms a highly ordered array in a region called the anterior banded zone. However, in corneal endotheliopathies such as Fuchs' endothelial dystrophy and the iridocorneal-endothelial syndrome large amounts of wide-spaced collagen are deposited posterior to Descemet's membrane in a grotesque parody of the anterior banded zone termed a posterior collagenous layer. The purpose of this study was to identify the composition of the wide-spaced collagen found in the Descemet's membrane of normal and diseased human corneas. Tissue from three normal human corneas, three from patients with Fuchs' endothelial dystrophy and five from patients with the iridocorneal-endothelial syndrome was prepared for immuno-electron microscopy by freezing or embedding in Lowicryl K4M resin. Immunocytochemistry on ultrathin sections was performed with antibodies to collagen Types I, III, V, VI and VIII, fibronectin, laminin, P component and tenascin. Ultrastructural labelling of the wide-spaced collagen in the anterior banded zone of normal and diseased corneas and also of the wide-spaced collagen in the posterior collagenous layer of all the diseased corneas was demonstrated with antibody to collagen Type VIII. Wide-spaced collagen was not labelled by any of the other antibodies used. Large amounts of Type VIII collagen are present in discrete regions of healthy and diseased Descemet's membrane. The deposition of Type VIII collagen may significantly influence the pathobiology of the corneal endotheliopathies.

Collagen↗

Angiomyolipoma arising in the colon.

Extrarenal angiomyolipomas are very rare. Here we report the first case of surgically resected angiomyolipoma of the descending colon that developed in a 50-yr-old man. The patient had no signs of or family history of tuberous sclerosis. He underwent a partial colectomy because the tumor obstructed the colon. Histologically, the tumor consisted of three components: mature fat cells, blood vessels, and smooth muscle cells, and was thereby diagnosed as an angiomyolipoma. Immunohistochemically, the proliferating smooth muscle cells were positive for vimentin, alpha-smooth muscle actin, and desmin. The tumor cells were negative for HMB-45, which is consistently expressed in renal angiomyolipomas.

Angiomyolipoma↗

[A clinical evaluation of fluconazole in deep seated fungal infections associated with hematological disorders].

The effectiveness of fluconazole on deep seated fungal infections associated with hematological disorders was evaluated in a multicenter clinical study. The underlying diseases included acute myeloblastic leukemia, acute lymphocytic leukemia, malignant lymphoma, adult T cell leukemia, multiple myeloma and others. Fluconazole (FLCZ) was administrated 100-400 mg/day intravenously or orally to 79 patients with systemic fungal infections complicated with hematological disorders and it was possible to evaluate clinical efficacies in 60 patients. 27 patients were diagnosed as having determinate systemic fungal infections and 33 patients suspected fungal infections. The clinical efficacies were 81.5% (22/27) in patients with diagnosed fungal infections and 57.6% (19/33) in patients with suspected fungal infections. The overall clinical efficacy was 68.3% (41/60). No side effects such as gastrointestinal symptoms, vascular pain and renal dysfunction were observed in this study. As for abnormal laboratory test, transient increases in GOT, GPT, Al-P, LDH, serum Na, Cl and decrease in serum K were observed in 9 patients (11.4%). These results indicated that FLCZ has a high therapeutic efficacy on deep seated fungal infections in patients with hematological disorders.

Aged↗