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81.
Karl Hård Albert Mekking Johannis P. Kamerling Georges A. A. Dacremont Johannes F. G. Vliegenthart 《Glycoconjugate journal》1991,8(1):17-28
Five brain-derived and 17 urinary oligomannose-type oligosaccharides were isolated by ion-exchange chromatography on Mono Q or Dowex, followed by HPLC on Lichrosorb-NH2 from a Persian cat suffering from -mannosidosis. The structures ofthe carbohydrate chains were determined by 500- or 600-MHz1H-NMR spectroscopy. Different oligosaccharide patterns were found in brain and urine. 99% of the urinary oligosaccharides possess an (1-6)-linked mannose residue attached to -mannose, whereas only 5% of the brain-derived oligosaccharides contain such a residue. Furthermore, of the urinary carbohydrate chains 71% end with Man1-4GlcNAc1-4GlcNAc and 29% end with Man1-4GlcNAc, whereas the corresponding amounts are 23% and 77%, respectively, for the brain-derived oligosaccharides.Abbreviations MLEV-17
composite pulse devised by M. Levitt
- HOHAHA
homonuclear Hartman-Hahn spectroscopy
- TPPI
time-proportional phase incrementation
- 2D
two dimensional
- GlcNAc
N-acetylglucosamine
- Man
mannose
- Fuc
fucose 相似文献
82.
Gerd Wallukat Gyorgy Nemecz Tibor Farkas Hartmut Kuehn Albert Wollenberger 《Molecular and cellular biochemistry》1991,102(1):35-47
Incubation of rocker-cultured neonatal rat heart cells with 3 mM L(+)-lactate led to a sharp increase in the sensitivity of cardiomyocytes to the beta-adrenergic agonist isoprenaline, as measured by their chronotropic response. This effect was accompanied by a reduction in the arachidonic acid content of the total phospholipids. The phospholipase A2-activator melittin as well as free arachidonic acid induced this supersensitivity to the same degree. On the other hand, the L(+)-lactate-evoked supersensitivity could be blocked by the phospholipase A2 inhibitors mepacrine and n-bromophenacyl-bromide, suggesting an involvement of phospholipase A2 in the process of beta-adrenergic sensitization. The sensitizing action of arachidonic acid was blocked by the lipoxygenase inhibitors esculetin and nordihydroguaiaretic acid, but not by the cyclooxygenase inhibitor indomethacin. Supersensitivity was likewise evoked by 15-S-hydroxyeicosatetraenoic acid (15-S-HETE), but not by 5-S-HPETE or 5-S-HETE. These findings suggest that the phospholipase A2-15-lipoxygenase pathway plays a role in the induction of beta-adrenergic supersensitivity in the cultured cardiomyocytes and point to a new physiological role of the lipoxygenase product 15-S-HETE.Abbreviations NDGA
nordihydroguaiaretic acid
- HETE
hydroeicosatetraenoic acid
- HPETE
hydroperoxyeicosatetraenoic acid 相似文献
83.
Niels Gregersen Brage S. Andresen Peter Bross Vibeke Winter Niels Rüdiger Stefan Engst Ernst Christensen Daniel Kelly Arnold W. Strauss Steen Kølvraa Lars Bolund Sandro Ghisla 《Human genetics》1991,86(6):545-551
Summary A series of experiments has established the molecular defect in the medium-chain acyl-coenzyme A (CoA) dehydrogenase (MCAD) gene in a family with MCAD deficiency. Demonstration of intra-mitochondrial mature MCAD indistinguishable in size (42.5-kDa) from control MCAD, and of mRNA with the correct size of 2.4 kb, indicated a point-mutation in the coding region of the MCAD gene to be disease-causing. Consequently, cloning and DNA sequencing of polymerase chain reaction (PCR) amplified complementary DNA (cDNA) from messenger RNA of fibroblasts from the patient and family members were performed. All clones sequenced from the patient exhibited a single base substitution from adenine (A) to guanine (G) at position 985 in the MCAD cDNA as the only consistent base-variation compared with control cDNA. In contrast, the parents contained cDNA with the normal and the mutated sequence, revealing their obligate carrier status. Allelic homozygosity in the patient and heterozygosity for the mutation in the parents were established by a modified PCR reaction, introducing a cleavage site for the restriction endonuclease NcoI into amplified genomic DNA containing G985. The same assay consistently revealed A985 in genomic DNA from 26 control individuals. The A to G mutation was introduced into an E. coli expression vector producing mutant MCAD, which was demonstrated to be inactive, probably because of the inability to form active tetrameric MCAD. All the experiments are consistent with the contention that the G985 mutation, resulting in a lysine to glutamate shift at position 329 in the MCAD polypeptide chain, is the genetic cause of MCAD deficiency in this family. We found the same mutation in homozygous form in 11 out of 12 other patients with verified MCAD deficiency. 相似文献
84.
Curtis J. Condon Su-Hua Chang Albert S. Feng 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1991,168(6):709-725
Summary Response characteristics of 130 single neurons in the superior olivary nucleus of the northern leopard frog (Rana pipiens pipiens) were examined to determine their selectivity to various behaviorally relevant temporal parameters [rise-fall time, duration, and amplitude modulation (AM) rate of acoustic signals. Response functions were constructed with respect to each of these variables. Neurons with different temporal firing patterns such as tonic, phasic or phasic-burst firing patterns, participated in time domain analysis in specific manners. Phasic neurons manifested preferences for signals with short rise-fall times, thus possessing low-pass response functions with respect to this stimulus parameter; conversely, tonic and phasic-burst units were non-selective and possessed all-pass response functions. A distinction between temporal firing patterns was also observed for duration coding. Whereas phasic units showed no change in the mean spike count with a change in stimulus duration (i.e., all-pass duration response functions), tonic and phasic-burst units gave higher mean spike counts with an increase in stimulus duration (i.e., primary-like high-pass response functions). Phasic units manifested greater response selectivity for AM rate than did tonic or phasic-burst units, and many phasic units were tuned to a narrow range of modulation rates (i.e., band-pass). The results suggest that SON neurons play an important role in the processing of complex acoustic patterns; they perform extensive computations on AM rate as well as other temporal parameters of complex sounds. Moreover, the response selectivities for rise-fall time, duration, and AM rate could often be shown to contribute to the differential responses to complex synthetic and natural sounds.Abbreviations
SON
superior olivary nucleus
-
DMN
dorsal medullary nucleus
-
TS
torus semicircularis
-
FTC
frequency threshold curve
-
BF
best excitatory frequency
-
PAM
pulsatile amplitude modulation
-
SAM
sinusoidal amplitude modulation
-
SQAM
square-wave amplitude modulation
-
MTF
modulation transfer function
-
PSTH
peri-stimulus time histogram 相似文献
85.
Albert Faradji Alain Bohbot Marion Schmitt-Goguel Norbert Roeslin Serge Dumont Marie-Louise Wiesel Christian Lallot Michel Eber Jacques Bartholeyns Philippe Poindron Georges Morand Jean-Paul Witz Francis Oberling 《Cancer immunology, immunotherapy : CII》1991,33(5):319-326
Summary The purpose of this phase I study was to evaluate the toxicity and biological activity of autologous blood-derived macrophages activated ex-vivo with recombinant human interferon (rhuIFN) [monokine-activated killer (MAK) cells] and administered intravenously to 11 lung cancer patients once a week for 6 consecutive weeks. Peripheral blood monocytes were collected by leukapheresis and then purified by counterflow elutriation. The MAK cells were generated by culturing the purified monocytes in Teflon bags for 7 days and adding rhuIFN to the cultured cells for the last 18 h. These MAK cells expressed differentiation-associated surface antigen MAX1, and were cytotoxic in vitro against tumour cell line U937. The MAK cells were infused at dose levels from 1 × 107 to 5 × 108 on an intrapatient dose-escalating schedule. No severe adverse side-effects occurred. Toxicity was mild to moderate [primarly fever (75%) and chills (32%)], non-dose-dependent, and non-cumulative. No consistent change in haemostatic function, or liver or renal function was observed. Dose-limiting toxicity was not reached at 5 × 108 cells (optimal dose reproduced for each patient). The maximum tolerated dose was not determined. The immunomodulatory activity of i.v. infused MAK cells was demonstrated both in vivo by significant increases in granulocyte count and neopterin level in the patients' peripheral blood postinfusion and in vitro by secretory products (IL-1. TNF, neopterin, and thromboplastin-like substance) in the culture supernatants. The in vivo traffic patterns of autologous MAK cells labelled ex-vivo with111In oxine were studied in 7 patients. Gamma imaging showed an immediate but transient lung uptake (<24 h), and a progressive uptake of radioactivity in the liver and spleen was seen from 6 h to 72 h post-infusion. Our results indicate that the preparation of high numbers of autologous, blood-derived MAK cells is a feasible procedure, and their transfusion is safe for patients. This immunotherapeutic approach seems to be encouraging from the point of view of establishing an adjuvant therapeutic modality in cancer patients with minimal residual disease.This work was supported in part by a grant 6911 from the Association pour la Recherche contre le Cancer (ARC), grants from the Ligue Nationale contre le cancer and the Ligues Regionales (Bas-Rhin, Haut-Rhin) contre le cancer, and contract 891013 from the Institut National pour la Santé et la Recherche Médicale (INSERM), France 相似文献
86.
Expression of membrane activation antigens on murine B lymphocytes stimulated with lipopolysaccharide 总被引:1,自引:0,他引:1
The expression of two membrane glycoproteins, RL388 antigen and transferrin receptor (TfR), was examined on murine B cells stimulated with lipopolysaccharide (LPS) in vitro. Immunofluorescent staining with monoclonal antibodies and flow cytofluorometric analysis were used to monitor the expression of these markers as a function of the time in culture, the state of membrane Ia antigen expression, the position in cell cycle, and the degree of B-cell differentiation. Freshly explanted splenic B cells expressed low levels of RL388 antigen and TfR. Following LPS stimulation, increased expression of RL388 antigen was detectable by 8 to 12 hr of culture, a time span characterized by increased Ia antigen expression, blast transformation, and G0 to G1 phase transition. The increased expression of TfR was apparent later and correlated with entry into late G1 phase and the onset of S phase. LPS-stimulated cell cultures treated with actinomycin D (G0/G1 block) exhibited increased expression of Ia antigen, but neither RL388 antigen nor TfR, whereas hydroxyurea treatment (G1/S block) allowed expression of all three markers. These results indicate that hyperexpression of RL388 antigen and TfR occurs during G1 phase and that these events are subsequent to Ia antigen hyperexpression. Finally, B cells in late G1 through M phase of the cell cycle simultaneously express high levels of RL388 antigen and TfR. These findings suggest that the expression patterns of RL388 antigen and TfR might be useful parameters for defining compartments of the murine B-cell cycle. 相似文献
87.
R E Hausman E T Dobi E J Woodford S Petrides M Ernst E B Nichols 《Developmental biology》1986,113(1):40-48
Myoblast aggregates provide a system for studying cell interactions which have several advantages over standard, stationary cultures. In gyrotory rotation, aggregate size can be controlled and is independent of cell migration. In muscle aggregates, fibroblasts are excluded, yet myoblast differentiation and fusion occur in a highly synchronous fashion. Specific PG binding occurs in chick or quail myoblast aggregates: in chick the peak of binding is at 35-36 hr. Aggregation is complete 16 hr before PG binding activity appears. This suggests either that gyrotory aggregation is not identical to myoblast recognition, or that PG binding activity occurs subsequent to myoblast recognition. Myoblast aggregates begin to release PG before 18 hr. The amount detected remains constant until binding begins at 34 hr when PG binding to the aggregates begins. Thus, both the release of PG and PG receptor activity are characteristics of the myoblasts and release of prostaglandin precedes appearance of the binding activity. As a first step in identifying the PG receptor and determining its appearance on the myoblast cell surface, we have prepared antisera against myoblast surfaces which blocks receptor-ligand interaction and have absorbed it against both peripheral and intrinsic membrane fractions. The results indicate that the PG receptor is a myoblast peripheral membrane macromolecule. 相似文献
88.
Sequence homologies of glucose-dehydrogenases of Bacillus megaterium and Bacillus subtilis 总被引:1,自引:0,他引:1
Peter Fortnagel Keith A. Lampel Klaus-Dieter Neitzke Ernst Freese 《Journal of theoretical biology》1986,120(4):489-497
The sequence homologies of the glucose dehydrogenase subunits of B. megaterium and B. subtilis are compared. From the known B. megaterium aminoacid sequence and the base sequence of the cloned B. subtilis structural gene we predict the B. megaterium structural glucose dehydrogenase gene. Assuming the minimal mutational changes to convert one gene into the other 23 transitions, 30 transversions, 1 inversion, 3 insertion-deletions, but no frameshifts are postulated necessary to interconvert the structural genes. The homology of both enzyme subunits of 85% reflects the close evolutionary distance between B. subtilis and B. megaterium. 相似文献
89.
Immunoreactivity and ouabain-dependent phosphorylation of (Na+ + K+)-adenosinetriphosphatase catalytic subunit doublets 总被引:2,自引:0,他引:2
Sodium dodecyl sulfate-polyacrylamide gel electrophoresis with 6% polyacrylamide was used to resolve the 100-kDa catalytic (alpha subunit) polypeptide of (Na+ + K+)-adenosinetriphosphatase from various tissues. The catalytic subunit was identified on immunoblots with antisera against mouse brain catalytic subunit and lamb kidney holoenzyme. Immunoblots and Coomassie Blue-stained companion gels showed double species of the 100-kDa subunit in sucrose gradient fractions of mouse brain and kidney, bovine grey and white matter, purified lamb kidney and duck salt gland holoenzyme, electroplax microsomes, and NaI-extracted microsomes of goldfish and rat brain. The apparent molecular mass differences between the two species in each tissue all ranged between 5 and 8 kDa. Both forms in rat brain and lamb kidney enzyme contain common epitopes reactive with antibodies immunoaffinity-purified on either species from mouse brain. In addition, ouabain-dependent acid-stable inorganic phosphate incorporation was tested with mouse brain, lamb kidney, and electroplax enzyme. Ouabain-dependent phosphorylation was demonstrated in both species in lamb kidney and electroplax and in the larger of the two forms in mouse brain. These results suggest that double species of the phosphorylatable subunit are present generally in epithelial as well as excitable tissues and in fish and avian as well as mammalian species. Work is needed to elucidate their qualitative and quantitative characteristics in different tissues. 相似文献
90.
Little is known of the selectivity of the blood-brain barrier at birth. Hexoses are transported through the barrier by a facilitating mechanism. To study the capacity of this mechanism to distinguish between analogs of D-glucose, we compared the transport of fluorodeoxyglucose, deoxyglucose, glucose, methylglucose, mannose, galactose, mannitol, and iodoantipyrine across the cerebral capillary endothelium in newborn Wistar rats. Cerebral blood flow, glucose consumption, and the blood-brain permeabilities of the hexoses were 25-50% of the adult values but the ratios between the permeabilities of the individual hexoses were similar to the ratios observed in adult rats. The mannitol clearance into brain was considerably higher than in adult rats (about 10-fold), indicating a higher endothelial permeability to small polar nonelectrolytes. The brain water content was higher in newborn than in adult rats and was associated with a higher steady-state distribution of labeled methylglucose between brain and blood. Hexose concentrations were determined relative to whole blood because the apparent erythrocyte membrane permeability to glucose was as high as in humans and thus considerably higher than in adult rats. The half-saturation concentration of glucose transport across the blood-brain barrier was considerably higher than in adult rats, about three-fold, suggesting that net blood-brain glucose transfer is less sensitive to blood glucose fluctuation in newborn than in adult rats. 相似文献