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Biomedical subjects

M Sakaguchi

Publications and source records attributed to M Sakaguchi.

At least 307 records · Page 17Linked to original sources
PubMed1994

Choroid plexus metastasis from gastric cancer--case report.

A 64-year-old male presented with a unique choroid plexus metastasis from gastric cancer. Computed tomography and magnetic resonance imaging demonstrated a moderately enhanced mass in the lateral ventricle. The tumor was totally removed and histological examination revealed adenocarcinoma. Systemic investigation revealed gastric cancer. The differential diagnosis for intraventricular masses should include the possibility of metastasis from unidentified primary lesions.

Adenocarcinoma↗
PubMed1994

Sensitization to cockroach allergens of asthma patients in Japan.

To evaluate the role of allergens from Periplaneta fuliginosa, which is the most predominant cockroach species in homes in Tokyo areas, for asthma sensitization, we measured specific IgE antibodies to two cockroaches, P. fuliginosa and Blattella germanica, and to a mite, Dermatophagoides farinae, in 171 sera from children with asthma by Pharmacia's CAP system. We found that 16% of the sera had anti-P. fuliginosa IgE, whereas 9.9% had anti-B. germanica and 85% anti-D. farinae IgE. Further, we measured the levels of Per f I (Per a I equivalent) allergen in the house dust from living room, kitchen and bedding. We detected the allergen in eight of ten homes. The Per a I equivalent levels in kitchen were higher than in other sites, but they were much lower than Der I and Der II as Dermatophagoides allergens.

Allergens↗
PubMed1994

[Protracted (lasting) presence of Japanese cedar pollen allergen (Cry j I) in house dust].

We investigated the relationship between the amounts of Cry j I in house dust and airborne Cryptomeria japonica pollen in the same location. Cry j I was still detected in house dust collected two weeks after airborne C. japonica pollen had disappeared. Disappearance of Cry j I in house dust coincided with the disappearance of symptoms in the C. japonica pollinosis patients who lived in the same area. Airborne Cupressaceae pollen appeared during the latter half of the C. japonica pollen season. Disappearance of Cupressaceae pollen did not coincided with the disappearance of the symptoms in C. japonica pollinosis patients. Therefore, some symptoms of C. japonica pollinosis patients after C. japonica pollen disappeared from the air may be caused by pollen which had attached to clothes and been brought indoors.

Air Pollution, Indoor↗
PubMed1993

Core glycosylation of cytochrome P-450(arom). Evidence for localization of N terminus of microsomal cytochrome P-450 in the lumen.

It was found that cytochrome P-450(arom) purified from human placenta microsomes is glycosylated, and the sugar chain was cleaved with endoglycosidase H (Endo H). The core glycosylation of P-450(arom) was examined with two heterologous expression systems, cultured insect cells and in vitro translation system. The P-450(arom) protein expressed in the insect cells was glycosylated, and the sugar chain was sensitive to Endo H. It was also glycosylated when translated with the wheat germ cell-free system in the presence of rough microsomal membrane, and the sugar chain could be removed by Endo H treatment. Since the P-450(arom) molecule has two potential glycosylation sites (Asn-12 and Asn-180), we replaced each of the 2 asparagine residues with alanine by site-directed mutagenesis and examined the glycosylation of the two mutant proteins in the cell-free system. The core glycosylation did not occur when the Asn-12 residue was mutated, whereas the mutant protein with modified Asn-180 residue was glycosylated. These results demonstrated that the potential glycosylation site (Asn-12) in the N-terminal portion of P-450(arom) is the site of glycosylation. We conclude that the N terminus of P-450(arom) is translocated across the endoplasmic reticulum membrane to be glycosylated at the luminal side.

Amino Acid Sequence↗
PubMed1993

Radiosensitization by a new potent nucleoside analog: 1-(1',3',4'-trihydroxy-2'-butoxy)methyl-2-nitroimidazole(RP-343).

PURPOSE: A new hypoxic cell sensitizer has been synthesized; this is a 2-nitroimidazole nucleoside analog having erythritol as a sugar moiety at the N-1 position of the imidazole ring (RP-343). Its possibility as a potent hypoxic cell sensitizer was compared with those of RP-170 and etanidazole. METHODS AND MATERIALS: Radiosensitization was tested in two murine tumors, EMT6 using in vitro and in vivo-in vitro assays and SCCVII using growth delay and TCD50 assays. Pharmacokinetic study was performed in Balb/c mice bearing EMT6 tumors and in Beagle dogs. LD50 of each sensitizer was obtained with ICR mice. RESULTS: As might be expected from the almost identical electron affinities of the three sensitizers, they were equally effective against hypoxic EMT6 cells in vitro. While having the lowest partition coefficient (0.035), RP-343 exhibited almost equally effective distribution to tumors and sensitizing radiation activity. An intravenous (i.v.) injection of 100 mg/kg of RP-343, RP-170 and etanidazole showed an almost equal sensitizer enhancement ratio (SER) of about 1.4 to solid EMT6 tumor under in vivo-in vitro assay and a virtually equal SER of 1.33-1.44 to solid SCCVII tumor under both tumor growth delay assay and TCD50 assay. A great advantage of RP-343 over RP-170 and etanidazole is its very much lower toxicity; their LD50 in mice were > 6.0, 4.3 and 4.8 g/kg, respectively, on i.v. injection. The lower toxicity of RP-343 was supported by its lower concentrations in the brain; the RP-343 AUC for brain was 0.43 times that of RP-170. Three indices were selected to compare the three nitroimidazoles. SER at 5% LD50 doses of RP-343, RP-170 and etanidazole was 1.66, 1.59 and 1.56. At the same toxicity levels, RP-343 was found to have better sensitization of solid tumors over both etanidazole and RP-170. The maximum tumor concentration/AUC for brain (Cmax,tumor/AUCbrain) ratios for RP-343 and RP-170 were 9.62 and 3.98. CONCLUSIONS: This extremely high ratio of RP-343 could explain its lower toxicity than RP-170 or etanidazole. The therapeutic risk index defined as D1.5/LD50 (D1.5 is the sensitizer dose to obtain the SER of 1.5 in vivo) for RP-343, RP-170 and etanidazole were 0.022, 0.033 and 0.036, respectively. Especially, the effectively lower therapeutic risk index for RP-343 presents the possibility of clinical advantage over etanidazole.

Animals↗
PubMed1993

A mitochondrial import factor purified from rat liver cytosol is an ATP-dependent conformational modulator for precursor proteins.

Rat liver cytosol contained an activity that stimulated the import of wheat germ lysate-synthesized precursor proteins into mitochondria. The activity was purified 10,000-fold from the cytosol as a homogeneous heterodimeric protein. This protein (termed mitochondrial import stimulation factor or MSF) stimulated the binding and import of mitochondrial precursor proteins. MSF was also found to recognize the presequence portion of mitochondrial precursors and catalyze the depolymerization and unfolding of in vitro synthesized mitochondrial precursor proteins in an ATP-dependent manner; in this connection, MSF exhibited ATPase activity depending on the important-incompetent mitochondrial precursor protein. The mitochondrial binding and import-stimulating activities were strongly inhibited by the pretreatment of MSF with NEM, whereas the ATP-dependent depolymerization activity was insensitive to the NEM treatment, suggesting that the process subsequent to the unfolding was inhibited with the NEM treatment. We conclude that MSF is a multifunctional cytoplasmic chaperone specific for mitochondrial protein import.

Adenosine Triphosphatases↗
PubMed1993

Marek's disease virus protein kinase gene identified within the short unique region of the viral genome is not essential for viral replication in cell culture and vaccine-induced immunity in chickens.

The open reading frame (ORF) of 1206 bp within the short unique region (Us) of Marek's disease virus type 1 (MDV1) shows significant homology with the herpes simplex virus type 1 US3 gene encoding protein kinase (PK). The lacZ gene of Escherichia coli was inserted within the ORF, designated MDV1-US3, of MDV1 K544 strain DNA by homologous recombination. The plaque-purified recombinant MDV1 stably expressed the beta-galactosidase encoded by the inserted lacZ gene in infected cells and replicated well as the parental K544 strain. Antibodies against both MDV1 antigen and beta-galactosidase were detected in the sera of chickens immunized with recombinant MDV1. Chickens vaccinated with the recombinant MDV1 were protected from challenge with virulent MDV1. The MDV1 US3 gene expressed by a baculovirus vector encoded a 44-kDa protein. Mouse antisera against the 44-kDa protein reacted with two proteins of 44 and 45 kDa in extracts of cells infected with MDV1 but not with MDV types 2 or 3. The PK activity was detected in immune complexes of the anti-44-kDa sera with extracts of cells infected with MDV1 but not with the recombinant MDV1. Thus, PK encoded from the MDV1-US3 is not essential for virus replication in cell culture and vaccine-induced immunity.

Amino Acid Sequence↗
PubMed1993

Effect of hyperthermia on the activity of 1-[(4'-hydroxy-2'-butenoxy)methyl]-2-nitroimidazole, which is cytotoxic to hypoxic cells.

The effect on EMT6/KU cells of a newly synthesized hypoxic cell sensitizer, 1-[(4'-hydroxy-2'-butenoxy)methyl]-2-nitroimidazole (RK28), combined with heat was determined in vitro under conditions of hypoxia. As compared with aerobic conditions, hypoxia produced a 1.30-fold increase in the cytotoxicity of the drug for mouse mammary EMT6/KU cells induced by 1 h heat treatment at 43 degrees C in medium with a normal pH. Hypoxia also reduced the surviving fraction of cells treated with both RK28 alone for 2 h and the same concentrations of RK28 and heat (43 degrees C) in combination. Those enhancement ratios corresponded to a 20.3- and > 345-fold increase, respectively. Moreover, concomitant treatment with RK28 and heat greatly inhibited the clonogenic activity of the EMT6/KU cells under conditions of in vitro hypoxia and in all experimental groups; there was a statistically significant difference in the time-response curves (P < 0.05). As hypoxic cells in a solid tumor are resistant to various anticancer drugs, RK28 combined with hyperthermia deserves further study for possible clinical applications.

Animals↗
PubMed1993

Phospholipids from the free-living nematode Caenorhabditis elegans.

The phospholipid and the fatty chain compositions of diacyl, alkylacyl and alkenylacyl glycerophospholipids of the free-living nematode, Caenorhabditis elegans, were investigated. The phospholipids were comprised of 54.5% ethanolamine glycerophospholipid (EGP), 32.3% choline glycerophospholipid (CGP), 8.1% sphingomyelin and 5.1% others. The most abundant fatty acid in CGP was eicosapentaenoic acid (20:5n-3). The fatty acids in CGP were more unsaturated than those in EGP. Alkenylacyl and alkylacyl subclasses accounted for 1.0 and 2.6%, respectively, of CGP and 14.0 and 19.6%, respectively, of EGP. At least 80% of the alkenyl and alkyl groups were 18:0 chains and the remaining were odd numbered chains. The potential presence of platelet-activating factor (PAF) was examined by bioassay, but PAF-like activity was not detected in the extracts of this nematode.

Animals↗
PubMed1993

Airborne cat (Fel d I), dog (Can f I), and mite (Der I and Der II) allergen levels in the homes of Japan.

We measured the airborne and floor dust allergen levels of the cat (Fel d I), dog (Can f I), and mite (Der I and Der II) allergens in 13 houses. Airborne allergens were sampled with a low-noise air sampler for 5 to 7 days in the living rooms where the inhabitants were living as usual. The mean levels of airborne Fel d I and Can f I in houses with cats or dogs were 5960 and 2880 pg/m3, respectively, which were about 160 and 100 times higher than levels of airborne Der I. In floor dust the mean levels of Fel d I and Can f I were 322 and 236 micrograms/gm fine dust, respectively, which were 59 and 10 times higher than the levels of Der I. These results suggest that the airborne cat and dog allergens might be important sources of allergens for persons who live in a house with those animals, because the absolute allergen levels in both the air and dust are significantly higher than those of mite.

Air↗
PubMed1993

Vascular reconstruction of carotid artery invaded by extensive parotid gland carcinoma.

A 63-year-old male with the left parotid gland carcinoma was operated with the reconstruction of the left carotid artery after the left radical neck dissection. The greater saphenous vein was used for the vein graft between the left common carotid artery and the medial cerebral artery. Postoperatively, a temporary loss of consciousness and a half body paresis of the contralateral side occurred, but they were recovered completely in 12 hours. Postoperative angiography showed a good blood flow in the reconstructed vessel.

Carcinoma↗
PubMed1993

Bilateral carcinomas of the maxillary sinus.

We report a 68-year-old male with a rare case of synchronous bilateral carcinomas of the maxillary sinus. A CT scan revealed a large tumour mass that extruded from the left maxillary sinus; tissue of soft density filled the right antrum which had intact bony walls. A probe antrostomy on the right side disclosed a tumour which was diagnosed histologically as the same poorly differentiated squamous cell carcinoma as that in the left antrum. The incidence and aetiology of this disorder are presented, and its diagnosis and management are discussed.

Aged↗
PubMed1993

Detection of a novel 9-kDa endoplasmic reticulum membrane protein in mammalian cells by chemical cross-linking with translocating nascent peptides.

It is widely accepted that a proteinous channel participates in the co-translational translocation of proteins across the endoplasmic reticulum (ER) membrane. Truncated mRNAs encoding N-terminal 70, 75, 88, and 110 amino acids of interleukin 2 were translated with wheat germ cell-free system in the presence of rough microsomal membrane (RM), and integral membrane proteins were probed with the translocating nascent peptides by using a cross-linking reagent (DSS). Two membrane proteins, 9 kDa (Cp9, cross-linking partner 9 k) and 39 kDa (Cp39, cross-linking partner 39 k), were cross-linked with the 75 amino acids nascent peptide. When NEM-treated RM was used for the translocation reaction, neither Cp9 nor Cp39 proteins were cross-linked. When the translation products were treated with puromycin before the cross-linking, both proteins were not cross-linked. The cross-linked products of Cp9 and Cp39 were not extracted by alkaline extraction of the membrane, not sensitive to endoglycosidase H, and did not bind to Con A-Sepharose. These results indicate that both of the cross-linking partners were nonglycosylated integral membrane proteins. Cp39 was cross-linked with the 70, 88, and 110 amino acid nascent peptides as well as the 75 amino acid peptide, whereas Cp9 reacted only with the nascent peptides consisting of 70 and 75 amino acid residues. Even after the digitonin treatment of the RM with the translocating intermediates, the cross-linked products with Cp9 and Cp39 were detected. Cp9 and Cp39 seem to be tightly associated with the ribosome-nascent peptide complex.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Importance of the proline-rich region following signal-anchor sequence in the formation of correct conformation of microsomal cytochrome P-450s.

A proline-rich region is present following the signal-anchor sequence in the amino-terminal portion of all known microsomal cytochrome P-450s. To assess the functional significance of the proline residues in this region, we systematically altered these residues of cytochrome P450(M1) (P450 2C11); one, two, and three proline residues out of the five in the region were exchanged for alanine residues. The wild-type and the mutated proteins were expressed in the fission yeast Schizosaccharomyces pombe under the control of nmt1 promoter. The wild-type and the mutated proteins were all highly expressed in the yeast cells (5-9% of the total membrane protein). The expressed wild-type P450(M1) showed a typical carbon monoxide difference spectrum of P-450 and the activity of testosterone hydroxylation, whereas all the mutated proteins constructed in the present study showed no characteristic P-450 spectrum, suggesting that the substitution of the proline residues in this region resulted in a defect of proper heme incorporation. Furthermore, the mutated proteins in which more than one proline residues had been exchanged were more sensitive to trypsin digestion than the wild type. From these results, we propose that the proline residues in the proline-rich region are crucial for the formation of the correct conformation of microsomal P-450 molecules.

Amino Acid Sequence↗
PubMed1993

A new method of counting airborne Japanese cedar (Cryptomeria japonica) pollen allergens by immunoblotting.

We have devised a new method of counting pollen allergen particles, modified from the fluorescent immunoblotting technique of Schumacher et al. Airborne Japanese cedar pollen allergens collected on Burkard's sampling tape were transferred onto a nitrocellulose membrane. The membrane was then treated with antiallergen mouse monoclonal antibody conjugated with alkaline phosphatase. Pollen allergens were detected as purple spots on the nitrocellulose membrane after phosphate substrate staining was performed. Pollen allergen particles were visible under a stereoscopic microscope or to the naked eye and could thus be counted easily. This new counting method takes less time than previous methods and requires no special skill.

Air↗