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PubMedDate not supplied

The fluorescence properties of hypocrellin B and its amino-substituted derivative: photoinduced intramolecular proton transfer and photoinduced intramolecular electron transfer.

We report on the emission spectra and emission quantum yields of a newly synthesized hypocrellin dye, 2-demethoxy-2,3-ethylenediamino hypocrellin B (EDAHB), and its parent HB in different solvents of varying polarity. Our results demonstrate that EDAHB is one of the few dyes that exhibit highly solvent polarity-dependent fluorescence in the useful region (680-730 nm). Therefore, it offers some applications in the biomedical field as a fluorescent probe molecule. The solvatochromic effect of EDAHB is proposed to be due to a distinct change in the dipole moment of the dye on excitation. A photoinduced intramolecular proton transfer and a photoinduced intramolecular electron transfer process are considered relevant for the fluorescence properties of HB and EDAHB, respectively.

Electrons↗
PubMed1994

Placental transfer, lacteal transfer and plasma protein binding of gemcitabine.

1. The placental transfer, lacteal transfer and plasma protein binding of gemcitabine have been studied in rat and dog after single intravenous administration of 10 mg/kg 14C-gemcitabine. 2. Radioactivity was distributed to the foetuses at 5 min after administration to rat on days 12 and 18 of gestation. The concentrations of radioactivity in the foetal liver, lung and kidney on day 18 of gestation were 4.0-6.4 times higher than in the maternal blood at 4 h after administration. Relatively high levels of radioactivity were noted in foetal tissues 24 h after administration, indicating slow elimination from the foetus. 3. The concentration of radioactivity in milk reached a maximum at 15 min after administration to the lactating rat on day 10 after delivery, then declined in a biphasic manner, and was below the detection limit at 48 h. The concentrations of radioactivity in milk were lower than plasma concentrations of radioactivity. 4. Plasma protein binding ratios were 10-16 and 1-7% between 5 min and 8 h after administration to the male rat and dog respectively. When fresh plasma from male rat, dog and adult man was spiked with 14C-gemcitabine at concentrations of 0.1-25 micrograms/ml, the plasma protein binding ratios were about 7% in both rat and dog, and 10% in man.

Animals↗
PubMed2002

[Experimental study on adenovirus-mediated transfer of p53 or adenovirus- mediated transfer of p53 combined with radiotherapy for human cervical cancer cell line HeLa cells].

OBJECTIVE: To evaluate the therapeutic efficiency of adenovirus-mediated transfer of p53(Ad-p53) or Ad-p53 combined with radiotherapy for human cervical cancer cell line HeLa cells. METHODS: HeLa cells were either transfected with Ad-p53 alone or with Ad-p53 combining with radiotherapy. Reverse transcription polymerase chain reaction(RT-PCR), the cell growth, morphological changes, cell cycle, apoptosis and molecular changes were measured using cell counting, microscopy, flow cytometry, DNA ladder, and in vivo therapy experiments to evaluate the therapeutic efficiency of the regimens. RESULTS: Ad-p53 could be transfected into HeLa cells and p53 mRNA could be expressed more in the targeted HeLa cells. Ad-p53 transfer had strong therapeutic effects to HeLa cells in vitro and in vivo (the inhibition rates were 61.8% and 54.8%, respectively), moreover, the combined administration of Ad-p53 and radiotherapy had stronger therapeutic effects in vitro and in vivo (the inhibition rate was 85.5% in vitro, and the inhibition rate was 77.4% in vivo). The inhibition rate by radiotherapy alone was 44.6% in vitro and 58.4% in vivo. Massive apoptosis of HeLa cells was induced by these regimens. Cell cycle analysis demonstrated that all these regimens could arrested HeLa cells in G(2)-M. CONCLUSIONS: After introduced into HeLa cells, Ad-p53 shows therapeutic efficiency for HeLa cells both in vitro and in vivo. Moreover, Ad-p53 could enhance therapeutic efficiency for HeLa cells when combined with radiotherapy.

Adenoviridae↗
PubMed1992

Vascularized bone transfer for tibial pseudarthrosis. Part II: Vascularized bone and muscle transfers. Exclusive free fibular bone graft.

The techniques of vascularized transfer of a bone segment, or of revascularization of a conventional bone autograft by a pedicle or a microsurgical muscular flap represent one of the most significant advances made during the last years for the treatment of large bone defects of the tibia with associated skin injury. The authors present their experience with 16 cases, including 5 microsurgical transfers.

Adult↗
PubMed1989

Transfer of the adenosine deaminase (ADA) gene of a B-lymphoblastoid cell line (LCL) to an ADA-deficient LCL by a microcell-mediated chromosome transfer technique.

As a model of somatic cell gene therapy, a normal adenosine deaminase (ADA) gene was introduced into a B-lymphoblastoid cell line (LCL) established from a patient with ADA deficiency by microcell-mediated chromosome transfer (MMCT). A LCL derived from his mother was used as a gene donor. Seven fusion experiments were performed and hybrid cells were pipetted into 123 wells. After selection in the presence of deoxyadenosine, cells grew in 12 wells at Week 9 after fusion. Among these wells, ADA activity of hybrids was low in 4 wells, 130-280% of that of the donor LCL in 7 wells and very high in one well. Hybrid cells in 4 wells with ADA-positive cells were investigated for the time-course of expression of ADA activity. In one well, ADA activity was expressed until Week 36, while, in 3 wells, ADA activity decreased or was lost between 21-36 weeks after fusion. These findings indicate the transfer of chromosome 20 containing a normal ADA gene into recipient cells and the deletion of this chromosome from some part of the hybrid cells. Karyotyping at Week 35 or 37 revealed 47 chromosomes in about 30% of the cells in 2 wells, which suggests that these hybrids were relatively stable in culture.

Adenosine Deaminase↗
PubMed1987

Applications of ammonium formate-catalytic transfer hydrogenation. Part V (1). Transfer hydrogenolysis of peptides containing p-chlorophenylalanine as a convenient method for preparation of deuterium labeled peptides.

Dehalogenation of chlorine bound to aromatic nuclei has been achieved using ammonium formate-catalytic transfer hydrogenation (AF-CTH) techniques. The use of deuterated ammonium formate as the transfer agent in the CTH process when performed in a deuterated solvent medium results in the predominant formation of the labeled product. Thus, ND+4 DCOO(-)-CTH of [D-Ala2, p-ClPhe4]-Leu-enkephalin in 80% CD3COOD/D2O yielded [D-Ala2, Phe (4D)4]-Leu-enkephalin. Levels of D-incorporation were measured by fast atom bombardment-mass spectrometry (FAB-MS) and/or by 13C n.m.r. spectroscopy. Using D-labeled and unlabeled ammonium formate in stoichiometrically similar reactions, it was concluded that the hydrogenation exhibited a primary kinetic isotope effect. Reactant and product concentrations were determined by amino acid analysis and reversed phase HPLC.

Deuterium↗
PubMed1985

Adoptive transfer of transplantation tolerance in the H-2 compatible mouse system CBA/C3H. Transfer of lymphocyte subpopulations into irradiated and non-irradiated mice.

Transfer of neonatally induced tolerance in the H-2 compatible CBA/C3H strain combination is possible with different efficiency by injection of adherent and non-adherent spleen cells, unseparated spleen cells and lymph node cells from C3H-tolerant CBA mice into sublethal irradiated CBA mice. The most efficient cell populations are adherent spleen cells and lymph node cells. Successful transfer of transplantation tolerance is not possible to non-irradiated mice. The adherent fraction of spleen cells and lymph node cells contains a suppressor cell population responsible for transplantation tolerance against non-H-2 antigens. The induced transplantation tolerance is not due to a chimaeric state of C3H-tolerant CBA mice.

Animals↗
PubMed1981

Adoptive transfer of experimental autoimmune thyroiditis (EAT) with in vitro activated lymph node cells from thyroglobulin-sensitized guinea pigs: characterization of the cell that transfers EAT.

Relatively low numbers of lymph node cells (LNC) from Strain 2 or Strain 13 guinea pigs sensitized with guinea pig thyroglobulin (GPTG) could transfer experimental autoimmune thyroiditis (EAT) to normal syngeneic recipients after in vitro culture with GPTG. The EAT induced in recipients of cultured LNC was similar in incidence and severity to EAT induced by active immunization with GPTG in complete Freund's adjuvant. The cells that were effective in transferring EAT were shown to be immunoglobulin-negative, nylon wool nonadherent, and Ia-negative. The effector cells were sensitive to irradiation after in vitro activation, indicating that cell proliferation in the recipient is required for development of EAT. Recipient animals often developed moderate to severe lesions of EAT yet none had detectable delayed hypersensitivity to GPTG and the majority also had no detectable anti-GPTG antibody.

Animals↗
PubMed1988

Fluorimetric distance determination by resonance energy transfer. Ribosome-bound transfer RNA.

Using the technique of singlet-singlet (Förster-type) resonance energy transfer, we have determined five distances in the programmed ribosome, either with the P site or with both the A and the P sites occupied. Two of the distances are new and two agree with earlier measurements; the fifth showed disagreement in detail with earlier results of others, but a consistent general trend. The distances substantiate a current model for the location of ribosomally bound tRNA, except in regard of the position of the 3' end of P-site tRNA, which seems according to our results to lie too far away from the 3' terminus of the 16 S RNA to be accommodated in the model. We present new evidence for the hypothesis that anomalously charged tRNA does not bind to the cognately programmed A site in the same way as does tRNA charged with an amino acid. Occupation of the A site restricts mobility of the 3' end of tRNA in the P site.

Energy Transfer↗
PubMed1998

Secondary donation of frozen embryos is more common after pregnancy initiation with donated eggs than after in vitro fertilization-embryo transfer and gamete intrafallopian transfer.

OBJECTIVE: To determine the availability of donated cryopreserved embryos. DESIGN: Retrospective review. SETTING: Community hospital-based donor oocyte program. PATIENT(S): Eighty-nine consecutive infertile couples and women who had 94 sets of embryos cryopreserved after pregnancy initiation with unfertilized donated eggs between January 1, 1991 and December 31, 1996. INTERVENTION(S): Cryopreservation of fertilized ova or cleaving embryos. MAIN OUTCOME MEASURE(S): Disposition of frozen embryos as of June 1, 1997. RESULT(S): Of the 94 sets of frozen embryos, 52 (55.3%) were thawed into the original recipient. At an average of 30 months since the treatment cycle, 26 (27.7%) sets of embryos remain in storage. Of the 16 sets of embryos not thawed for transfer, 11 sets (11.7%) were donated and 5 sets (5.3%) were destroyed. The fraction of spare embryos donated was much higher after pregnancy initiation with unfertilized donated eggs than after IVF-ET and GIFT (68.8% versus 19.1%, respectively). CONCLUSION(S): Couples and women who did not use their frozen embryos after pregnancy initiation with unfertilized donated eggs were twice as likely to donate them as to have them destroyed. Secondary donation of cryopreserved embryos was much more common after pregnancy initiation with unfertilized donated eggs than after standard IVF-ET and GIFT.

Adult↗
PubMed1981

Position of transfer ribonucleic acid on Escherichia coli ribosomes. Distance from the 3' end of 16S ribonucleic acid to three points on phenylalanine-accepting transfer ribonucleic acid in the donor site of 70S ribosomes.

Escherichia coli 16S RNA from 30S ribosomal subunits was isolated, oxidized at the 3' end, and labeled with the thiosemicarbazide derivatives of fluorescein or eosin. Labeled 16S RNA was reconstituted into 30S subunits. They were almost fully active compared to 30S subunits reconstituted from unlabeled 16S RNA by using a poly(uridylic acid)-directed polyphenylalanine synthesis assay. Fluorophores were placed at three different positions of tRNAPhe. E. coli and yeast tRNAPhe were oxidized at the 3' end and labeled with the thiosemicarbazide derivative of fluorescein or with the hydrazide of N-methylanthranilic acid. The Y base in the anticodon loop of yeast tRNAPhe was replaced by proflavin or 1-aminoanthracene. Also, E. coli tRNAPhe was photochemically cross-linked between 4-thiouridine at position 8 and cytidine at position 13. After reduction, this site was used as a fluorescent probe. The labeled tRNAs were bound into the peptidyl site of 70S ribosomes, and then the distances from the fluorophore in the modified tRNA to the fluorophore at the 3' end of 16S RNA were measured by nonradiative energy transfer. Calculations were based on measurements of fluorescence lifetimes. The distances to the 3' end of 16S RNA were found to be as follows: 3' end of tRNA, 67-74 A; cross-linked t RNA, 53-60 A; anticodon loop of tRNA, greater than 61 A.

Binding Sites↗
PubMed1980

Excited indole-3-aldehyde from the peroxidase-catalyzed aerobic oxidation of indole-3-acetic acid. Reaction with and energy transfer to transfer ribonucleic acid.

The horseradish peroxidase catalyzed aerobic oxidation of the auxin indole-3-acetic acid generates triplet indole-3-aldehyde in high yield. The excited species is quenched by oxygen with formation of singlet oxygen, which is responsible for the observed photon emission and can be trapped by suitable agents. tRNA dramatically enhances the emission as a result of energy transfer from triplet indole-3-aldehyde to a 4-thiouridine group in tRNA. Triplet indole-3-aldehyde also adds covalently to tRNA. The results provide a possible mechanism for the auxin-tRNA interaction in vivo.

Aldehydes↗
PubMed1973

Analysis of isoaccepting transfer ribonucleic acid species of Bacillus subtilis: changes in chromatography of transfer ribonucleic acids associated with stage of development.

Changes in chromatographic profiles of tyrosyl-, leucyl-, tryptophanyl-, and lysyl-transfer ribonucleic acids (tRNAs) are presented as a function of the growth stage in Bacillus subtilis. All of the tRNA groups investigated expressed different temporal patterns of change in isoaccepting species. Tyrosyl-tRNAs were the earliest to change and were followed by changes in leucyl- and then tryptophanyl-tRNAs. Lysyl-tRNAs were unique in having two times of change: one early and one very late. As an aid in understanding the temporal aspect of tRNA alterations during sporulation, the chromatographic profiles of aminoacyl tRNAs from an early blocked asporogenous mutant were studied. The asporogenous mutant used was blocked at the axial filament stage, stage 0 of sporulation. Nevertheless, those tRNAs which showed differences between the spore and cells in exponential growth exhibited similar changes in the asporogenous mutant after 24 h of growth. The data suggest that several tRNA changes occur during development in B. subtilis but that the events leading to these changes are either independent of, or occur before, stage 0 of sporulation, except in the case of lysyl-tRNA.

Amino Acyl-tRNA Synthetases↗
PubMed2002

Molecular characterization of rabbit phospholipid transfer protein: choroid plexus and ependyma synthesize high levels of phospholipid transfer protein.

Phospholipid transfer protein (PLTP) plays an important role in plasma lipoprotein metabolism. However, PLTP is expressed in a wide range of tissues suggesting additional local functions. To analyze the tissue distribution of PLTP in an animal with high-level expression of the structurally and functionally related CETP, we have cloned the full-length cDNA of rabbit PLTP (1,796 bp). Rabbit PLTP cDNA shows high homology to human, murine, and porcine PLTP cDNA, averaging 86.1%, 80.4%, and 86.1%, respectively. Interestingly, the C-terminus contains a unique seven amino acid insertion not found in previously characterized mammalian PLTPs. In clear contradistinction to human PLTP, rabbit PLTP mRNA was prominent in brain. In situ hybridization studies revealed specific, high-level synthesis of PLTP mRNA in choroid plexus and ependyma, the organs responsible for production of cerebrospinal fluid. Consistent with these findings, PLTP activity in cerebrospinal fluid amounted to 23% +/- 3% of that in rabbit plasma. In contrast, neither CETP mRNA nor CETP activity were detectable in rabbit brain.A role of PLTP in the central nervous system could involve some of its actions previously established in vitro, like proteolysis of apolipoproteins, and be physiologically relevant for neurodegenerative disorders such as Alzheimer's disease.

Amino Acid Sequence↗
PubMed1993

A continuous spectrophotometric assay for the aminoacylation of transfer RNA by alanyl-transfer RNA synthetase.

A continuous spectrophotometric assay is described for the aminoacylation reaction catalyzed by Escherichia coli alanyl-transfer RNA synthetase. The assay is based on coupling the alanyl-tRNA synthetase-dependent formation of AMP to the lactate dehydrogenase oxidation of NADH. Oxidation of NADH, as monitored at 340 nm, is shown to be stoichiometric with the formation of alanyl-tRNA(Ala). This assay will facilitate the rapid accumulation and analysis of kinetic data for alanyl-tRNA synthetase and should be applicable to aminoacyl-tRNA synthetases in general.

Acylation↗
PubMed1996

Retroviral vector-mediated transfer of the galactocerebrosidase (GALC) cDNA leads to overexpression and transfer of GALC activity to neighboring cells.

Galactocerebrosidase (GALC) is responsible for the lysosomal catabolism of certain galactolipids, including galactosylceramide and psychosine. Patients with GALC deficiency have an autosomal recessive disorder known as globoid cell leukodystrophy (GLD) or Krabbe disease. Storage of undegraded glycolipids results in defective myelin and the characteristic globoid cells observed on pathological examination of the central and peripheral nervous systems. Most patients have the infantile form of GLD, although older individuals are also diagnosed. Recently the human, mouse, and canine GALC genes were cloned, and mutations causing GLD have been identified. We now describe the construction of a vector containing human GALC cDNA (MFG-GALC), and the transduction of cultured skin fibroblasts from molecularly characterized Krabbe disease patients, as well as rat brain astrocytes and human CD34(+) hematopoietic cells, using retrovirus produced by the psi-CRIP amphotropic packaging cell line. The transduced fibroblasts showed extremely high GALC activity (up to 20,000 times pretreatment levels, about 100 times normal). GALC was secreted into the media and was taken up by untransduced fibroblasts from the same or a different patient. Mannose-6-phosphate receptor-mediated uptake was only partially responsible for the efficient transfer of GALC to neighboring cells. Additional studies confirmed the presence of normal GALC cDNA and mRNA in the transduced cells. The GALC produced by the transduced cells and donated to neighboring untransduced cells was localized to lysosomes as demonstrated by the normal metabolism of [14C]stearic acid-labeled galactosylceramide produced from endocytosed [14C]sulfatide.

Animals↗