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Biomedical subjects

Y Fujii

Publications and source records attributed to Y Fujii.

At least 703 records · Page 39Linked to original sources
PubMed1993

Expression of human immunodeficiency virus type 1 Nef antigen on the surface of acutely and persistently infected human T cells.

The authors have previously shown the role of human immunodeficiency virus type 1 (HIV-1) Nef protein as a growth inhibitor to CD4+ T lymphocytes. We now report that the Nef antigen is partly expressed on both acutely and persistently infected human T cells. To investigate the cell surface expression of the Nef antigen, murine monoclonal antibodies (mAbs) were prepared by immunization with a recombinant Nef protein. The recombinant Nef was expressed by a baculovirus expression system as a truncated Nef protein with 22 kDa containing the middle to the C-terminus. Three clones were found to produce mAbs with IgM isotype against Nef protein by ELISA with the same truncated Nef. All these mAbs reacted on immunoblotting with two forms of Nef, 25 kDa and 27 kDa, in an HIV-1-infected human T-cell line and with the 27 kDa Nef in retroviral vector-infected mouse fibroblasts expressing a full-length Nef protein. Membrane immunofluorescence and flow cytometry with these mAbs revealed the Nef antigen to be expressed, at least in part, on the surface of these cells. Thus, the cell-surface form of Nef might play an important role in the selective depletion of CD4+ cells in HIV-1 infection.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Evidence for the role of human immunodeficiency virus type 1 Nef protein as a growth inhibitor to CD4+ T lymphocytes and for the blocking of the Nef function by anti-Nef antibodies.

Human immunodeficiency virus type 1 (HIV-1) can lead to a profound CD4+ T-cell deficiency. To examine the functional role of HIV-1 Nef protein on the marked loss of CD4+ cells, Nef protein was expressed in and purified from Escherichia coli as a fusion protein with T7 phage gene10 product (Nef-gene10). When peripheral blood mononuclear cells (PBMC) from healthy donors were cultivated in the presence of Nef-gene10 or the gene10 product as well as interleukin-2 (IL-2), it was found that the Nef-gene10, but not the gene10 product, induced a remarkable decline in the CD4/CD8 ratio and in the response to phytohaemagglutinin of PBMC as well as of nylon wool-passed purified T cells. Nef-gene10 inhibited the proliferation of CD4+ cells, but did not kill the cells. This suppression of the IL-2-dependent proliferation of CD4+ cells by Nef-gene10 seemed to be due to enhanced production of several lymphokines, especially of interferon-gamma. Thus, Nef protein might be partly responsible for the selective depletion of CD4+ cells in HIV-1 infection. Furthermore, the Nef-induced decline in the CD4/CD8 ratio was interrupted by anti-Nef antibodies, suggesting the possibility that a vaccine which resulted in the production of such functional Nef antibodies would be useful in the treatment of HIV-1-induced immunodysfunction.

Animals↗
PubMed1993

Developmental features of the brain in preterm and fullterm infants on MR imaging.

Normal development and maturation in pre- and postnatal periods were studied using MR imaging. For this purpose, we performed MR imaging at a postmenstrual age of 37-44 weeks in both low-risk preterm and fullterm infants and assessed the myelination pattern and the dimension of the pituitary gland, corpus callosum, pons and cerebellar vermis. There were no differences in stages of myelination and the size of these structures in both groups. MR imaging was also performed in infants with various cerebral injuries. Focal or diffuse areas of hyperintensity on T2-weighted images and delayed myelination were the commonly observed abnormal findings in these infants.

Brain↗
PubMed1993

Uptake of phosphatidylserine liposomes by rat Peyer's patches following intraluminal administration.

Uptake of the nonabsorbable marker 6-carboxyfluorescein was investigated both free and encapsulated in liposomes as a function of their surface charge and hydrodynamic diameter in rat Peyer's patch and nonpatch tissue. Significant uptake of the marker occurred only when encapsulated in liposomes consisting of at least 25 mol% phosphatidylserine and was highest in Peyer's patches. 6-Carboxyfluorescein encapsulated in liposomes equal to or greater than 374 nm was preferentially taken up by Peyer's patches. There was a trend to higher uptake in lower intestinal segments. These findings were supported by fluorescence microscopic observations. Uptake by Peyer's patches was specific for negatively charged liposomes as judged from competition studies.

Analysis of Variance↗
PubMed1993

Expression of the HN, F, NP and M proteins of Sendai virus by recombinant vaccinia viruses and their contribution to protective immunity against Sendai virus infections in mice.

Recombinant vaccinia viruses (RVVs) expressing each of the haemagglutinin-neuraminidase (HN), fusion (F), nucleocapsid (NP) and matrix (M) proteins of Sendai virus were constructed to investigate their capacities to induce protective immunity against Sendai virus infections. The proteins expressed in cultured cells appeared to be authentic with respect to their antigenicity, electrophoretic mobility, surface expression of the HN and F proteins and, in the case of the HN protein, biological activities. Mice inoculated intranasally with these RVVs developed serum antibodies to the respective Sendai virus proteins, suggesting their in vivo expression. In mice immunized with RVV carrying either the HN or the F gene, growth of the challenging Sendai virus was almost completely suppressed in the lung, indicating their capacities to induce effective protective immunity against Sendai virus infections. In contrast, in mice immunized with RVV carrying the NP or M gene, the challenging virus propagated as well as in the control mice, but the virus titres were significantly lower at the late stage of infection than those in the control mice, suggesting that they can also induce protective immunity especially at the late stage of the challenge infection.

Animals↗
PubMed1993

Functional properties of pro region of Escherichia coli heat-stable enterotoxin.

Escherichia coli heat-stable enterotoxin Ip (STp) is synthesized as the 72-amino-acid residue precursor consisting of three regions: pre region (amino acid residues 1 to 19), pro region (amino acid residues 20 to 54), and mature ST (mST) region (amino acid residues 55 to 72). We examined the role of the pro sequence of STp in enterotoxigenicity of a strain by deleting the gene fragment encoding amino acids 22 to 57. This deletion caused a remarkable reduction of its enterotoxic activity of culture supernatant. In order to analyze the sequence responsible for the function of the pro region, two additional deletion mutants were made. The deletion of the sequence covering amino acids 29 to 38, which is conserved in all sequences of ST reported, brought about a significant reduction of enterotoxic activity but the deletion of the non-conserved sequence (amino acids 40 to 53) did not. This result shows that conserved sequence is mainly responsible for the function. Subsequently, to examine the mechanism of action of the pro region, plasmids carrying DNA sequences of hybrid proteins consisting of pre-pro-nuclease, pre-mST-nuclease, pre-pro-mST-nuclease and pre-pro-nuclease-mST were constructed. Amino acid sequence determination and SDS-polyacrylamide gel analysis revealed that these fusion proteins were cleaved between pre sequence and pro sequence during secretion and the cleaved fusion proteins were accumulated in periplasmic space. But the amount of hybrid protein accumulated in the periplasmic space varied among the strains. That is, the amount of the pre-pro-nuclease gene product that accumulated in the periplasmic space was the highest of all fusion gene products. These results indicate that the existence of the mST region strongly interferes with the translocation of the gene product into the periplasmic space and that the pro region functions to guide the mST region into the periplasmic space.

Amino Acid Sequence↗
PubMed1993

Identification and characterization of heat-stable enterotoxin II-producing Escherichia coli from patients with diarrhea.

Stock strains of Escherichia coli isolated from patients with traveller's diarrhea were examined for production of heat-stable enterotoxin II (STII). Of 400 strains examined, 3 were found to produce STII. The nucleotide sequence of the STII gene of these human strains was shown to be identical to that of porcine strains. Cultured cells of these strains induced fluid accumulation in ligated mouse intestinal loops and the activity was neutralized by anti-STII antiserum. These results suggest that STII-producing enterotoxigenic E. coli can cause human diarrhea.

Animals↗
PubMed1993

Establishment and characterization of BALB/c retroperitoneal sarcoma with spontaneous liver metastases.

The objective of this study was to examine the identity and characteristics of a spontaneously occurring murine retroperitoneal tumor of BALB/c mouse origin that selectively metastasized to the liver. From the primary tumor, a permanent cell line, termed LMFS (liver metastasis from sarcoma) was established in vivo and in vitro. After a subcutaneous injection of more than 1 x 10(5) cells in the side back of mice, the LMFS cells proliferated at the inoculation site (100% take) and induced metastatic nodules spontaneously in the liver, but not in the lung. By the limiting dilution technique, a cloned cell line, LMFS-1, was established in vitro. The LMFS-1 cell line had similar morphological characteristics to the LMFS cells both in vitro and in vivo. The doubling time of the LMFS-1 cell line was 10 h in passage 60. The number of chromosomes ranged from 71 to 108 and 93% of metaphases showed near-tetraploidy. In microscopic examination, no specific arrangement of the LMFS tumor cells was seen; the LMFS cell had medium- to large-sized atypical nuclei and clear and large cytoplasm. Electronmicroscopy showed that the cytoplasm of the LMFS cell had a moderate amount of rough-surfaced endoplasmic reticulum but no desmosomes or microvilli. Immunohistochemically, the LMFS cells were positive for vimentin, but showed no reaction for keratin or cytokeratin. Therefore, the LMFS tumor was considered to be an undifferentiated sarcoma. The LMFS cell line should be a useful tool not only for studies of metastasis, but also for experiments on the therapy of hepatic tumors.

Aneuploidy↗
PubMed1993

F0-containing noninfectious Sendai virus can initiate replication in mouse lungs but requires a relatively long incubation period.

The replication of LLC-MK2-grown noninfectious Sendai virus, containing exclusively fusion (F) glycoprotein precursors, was examined in the mouse lung to study the accessibility of virus inoculated intranasally to the virus activator present in the lung. When mice were intranasally inoculated with various doses of the virus after in vitro activation with trypsin, the 50% mouse infectious dose (MID50) was determined to be 0.7 cell-infectious units (CIU) per mouse, indicating that one infectious unit of Sendai virus is enough to initiate replication in the mouse lung and that the present experimental system is highly sensitive. On the other hand, in mice inoculated with virus not treated with trypsin, virus replication in the lung was recognized even in mice inoculated with samples containing no infectious virus, and the MID50 was determined to be 67.5 CIU per mouse (here, CIU were assayed after in vitro trypsin treatment). When mice were infected with 20 MID50 of trypsin-treated infectious and untreated noninfectious viruses (an approximately 100-fold greater amount of noninfectious virus than of infectious virus was used), the noninfectious virus was found to require 2 more days of incubation than the infectious virus, and many of the F proteins synthesized in the lungs of mice infected with the F0-containing virus were present in the cleaved form. In addition, the infection of mice with noninfectious virus was strongly suppressed by aprotinin, a serine protease inhibitor. These results indicate that Sendai virus can initiate replication in the mouse lung even with the F0-containing noninfectious virus and strongly suggest that this infection process is mediated by cleavage activation of the F0 proteins of inoculated viruses by a serine protease(s) present in the lumen of the mouse respiratory tract but that activation of the noninfectious virus is an inefficient process.

Animals↗
PubMed1993

Increased serum levels of monosialo-alpha-fetoprotein in hepatocellular carcinoma and other malignancies.

Serum alpha-fetoprotein (AFP) from cord blood and from patients with hepatitis, cirrhosis, hepatocellular carcinoma, gastrointestinal tumors and yolk sac tumor was analyzed by extended agarose gel electrophoresis coupled with our sensitive detection method of antibody-affinity blotting. AFP was separated into AFP-A, AFP-B and AFP-C from the anode to the cathode, corresponding to disialo-, monosialo- and asialo-AFP, respectively, as revealed by the results of neuraminidase digestion of serum AFP. AFP-Af, which migrated ahead of AFP-A as band or leading smear and varied widely in intensity, was eliminated in calculating the proportions of other band intensities. Disialo-AFP was the major component and monosialo-AFP the minor one in benign conditions, the latter being 4.2 +/- 6.0% in chronic hepatitis and 9.0 +/- 8.9% in cirrhosis. Monosialo-AFP in hepatocellular carcinoma was increased significantly, the proportion being 29.9 +/- 11.2%. AFP in other malignancies was further characterized by the appearance of asialo-AFP.

Carcinoma, Hepatocellular↗
PubMed1993

Urinary growth hormone excretion in preterm neonates.

We measured urinary growth hormone (U-GH), beta 2-microglobulin (U-B2) and serum growth hormone (S-GH) in preterm neonates on days 1, 4, 7, 14 and 28 of age. U-GH as well as U-B2 were high, particularly in the more premature and sick neonates with respiratory failure requiring mechanical ventilation. U-GH showed significant positive correlations with U-B2 throughout the study but with S-GH only on day 7. Therefore, we conclude that in preterm neonates, U-GH mainly reflects the degree of renal proximal tubular function, which is determined by the degree of renal maturation of the subject and of tubular injury due to disease states such as respiratory failure.

Aging↗
PubMed1993

Measurement of lumbar spinal bone mineral density in preterm infants by dual-energy X-ray absorptiometry.

Lumbar spinal bone mineral density (BMD) was measured in 40 preterm infants by dual-energy X-ray absorptiometry (DXA). During the first several months of life, their BMD was considerably lower than that of normal term infants and the osteopenia was more pronounced in the more preterm and smaller infants. Weak (inverse) correlations were found between the BMD and urinary calcium/creatinine or tubular phosphorus reabsorption ratio. Rickets-like changes in the forearm bones did not predict the greater spinal osteopenia. Follow-up study was performed in 10 preterms. In 3 of the 4 who underwent the last DXA between 8 and 12 months, BMD had improved remarkably. Our present study shows the potential of DXA for the assessment and management of osteopenia of prematurity.

Absorptiometry, Photon↗
PubMed1993

Quadraparesis after a shunting procedure in a case of cervical spinal neurinoma associated with hydrocephalus: case report.

The authors report a rare case of cervical spinal neurinoma in a patient who presented with symptoms originating from hydrocephalus. Her symptoms improved after a ventriculoperitoneal shunt was inserted, although progressive quadraparesis appeared when she began to walk. Magnetic resonance imaging revealed a cervical tumor. When it was removed, the patient's quadraparesis improved. Associated spinal tumors should be considered in the treatment of hydrocephalus of unknown origin.

Cerebrospinal Fluid Shunts↗
PubMed1993

Pharmacokinetics of cyproheptadine and its metabolites in rats.

To investigate the pharmacokinetics of cyproheptadine (CPH) and its metabolites, the plasma concentration and urinary excretion of CPH and its detectable metabolites were determined after intravenous (i.v.) administration of parent or synthesized metabolites to rats. The plasma CPH concentration-time course was subjected to biexponential calculation following the i.v. administration of CPH, producing the temporal and low plasma concentrations of desmethylcyproheptadine (DMCPH) and the sustained plasma concentrations of desmethylcyproheptadine-epoxide (DMCPHepo). DMCPH was also eliminated, according to the biexponential equation, after i.v. administration of performed DMCPH, forming DMCPHepo in plasma. On the other hand, no detectable DMCPHepo was found in plasma after the i.v. administration of cyproheptadine epoxide (CPHepo). All compounds administered had large distribution volumes and were almost entirely excreted as DMCPHepo in urine; this excretion continued for a long time. However, the urinary excretion pattern of DMCPHepo after CPHepo was different from those after CPH and DMCPH. The mean residence times of the epoxidized metabolites estimated from the urinary data were much longer than those from the plasma concentration data, suggesting either a gradual reflux of the metabolites from a tissue depot into systemic circulation under those plasma concentrations close of detection limit, or some interaction which delays excretion into the urine. This study suggests that both metabolic pathways of CPH, through DMCPH and CPHepo, to DMCPHepo are possible, but that the demethylation of CPH largely occurs prior to epoxidation; also that the extensive and persistent distribution of DMCPHepo to tissues may relate to the toxicity of CPH reported in rats.

Animals↗
PubMed1993

Isolation of camelliaside C from "tea seed cake" and inhibitory effects of its derivatives on arachidonate 5-lipoxygenase.

A new flavonol glycoside, camelliaside C, was isolated from "tea seed cake" prepared from the defatted seeds of Camellia sinensis O. Kuntze. The structure was determined as kaempferol 3-O-beta-D-galactopyranosyl-(1-->2)-beta-D-glucopyranoside by spectroscopic methods (FAB-MS, UV, IR, 1H- and 13C-NMR) and the enzymatic transformation of camelliaside C to astragalin. Camelliaside C showed an inhibitory effect on the arachidonate 5-lipoxygenase of RBL-1 cells (IC50:1.4 x 10(-4)M) as did camelliaside A and B isolated from the same product.

Animals↗
PubMed1993

Absolute configuration of L-methionine sulfoximine as a toxic principle in Cnestis palala (Lour.) Merr.

An unusual amino acid, L-methionine sulfoximine (1), has been isolated from the fresh seeds of Cnestis palala (Lour.) Merr. [Connaraceae]. The absolute configuration of the natural sulfoximine (1) was confirmed to be 2(S)-methionine S(S)-sulfoximine [(2S,SS)-2-amino-4-(S-methylsulfonimidoyl)-n-butanoic acid] by comparison of the [alpha]D value and IR spectrum with those of authentic samples obtained through the optical resolution of synthetic materials. Acute toxicity of the seeds of C. palala in a beagle dog was also studied.

Animals↗