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111.
Christophe Philippe Ccile Arnould Frdrique Sloan Hans van Bokhoven Saskia D. van der Velde-Visser Michle Chery H. Hilger Ropers Simone Gilgenkrantz Anthony P. Monaco Frans P. M. Cremers 《Genomics》1995,27(3)
In a previous study, we have developed a panel of chromosomal rearrangements for the physical mapping of the q13-q21 region of the human X chromosome (Philippe et al., Genomics 17: 147-152, 1993). Here, we report the physical localization of 36 additional polymorphic markers by polymerase chain reaction analysis. The high density of chromosomal breakpoints in Xq21 allows us to map 58 DNA loci in 22 intervals. As a result, this segment of the X chromosome is saturated with approximately three sequence tagged sites per megabase of DNA, which will facilitate the construction of a YAC contig of this region. 相似文献
112.
Expression of platelet membrane glycoproteins and alpha-granule proteins by a human erythroleukemia cell line (HEL) 总被引:28,自引:1,他引:27 下载免费PDF全文
A Tabilio J P Rosa U Testa N Kieffer A T Nurden M C Del Canizo J Breton-Gorius W Vainchenker 《The EMBO journal》1984,3(2):453-459
We demonstrate that HEL, a human erythroleukemic cell line, has numerous megakaryocytic markers which were markedly enhanced following the addition of the inducers dimethyl sulfoxide or 12-O-tetradecanoylphorbol-13-acetate to the culture medium. Ultrastructural and cytochemical studies showed: (i) the presence of organelles morphologically resembling the platelet alpha-granules; and (ii) a peroxidase activity with the same characteristics as that specifically found in platelets. The platelet alpha-granule proteins (von Willebrand factor, platelet factor-4 and beta-thromboglobulin) were immunologically detected in the HEL cell cytoplasm and their amounts increased after induction. Of particular interest was the presence of platelet membrane proteins. A monoclonal antibody specific for glycoprotein Ib bound to HEL cells. Platelet membrane glycoproteins IIb and IIIa were identified on intact cells using specific antibodies in a binding assay or in cell lysates using either crossed immunoelectrophoresis or an immunoblotting procedure following SDS-polyacrylamide gel electrophoresis. Most HEL cells also expressed the platelet alloantigen PIA1. All of the platelet membrane proteins were present in higher amounts after induction. Glycophorin A, specific for the erythroid lineage, was also detected on HEL cells. Thus, while confirming the presence of erythroid markers, our studies provide evidence that the HEL cell line also expresses platelet antigens. As such, HEL cells represent a unique system with which to study the biosynthesis of platelet-specific proteins and glycoproteins. 相似文献
113.
P Pradelles J. Maclouf J. Grassi A. Del Maschio 《Prostaglandins & other lipid mediators》1984,28(5):661
The obtention of icosanoids tracers of high specific radioactivity (e.g. radioiodinated tracers) has been a prerequisite for the development of radioimmunoassays that would allow the detection of femtomoles amount of these substances from biological medium. However, recent attempts to develope immunoassays using haptens (e.g. prostaglandins or thromboxane B2) labeled with enzymes have turned out to be disappointing because of their poor sensitivity. Using the acetylcholinesterase (AChE) from “electrophorus electricus” as a tracer we have labeled LTC4 after coupling it to the enzyme with 1,5-difluoro-2,4-dinitrobenzene as a bifunctional reagent. The use of 96-well microtiter plates coated with pig anti-rabbit immunoglobulin antibodies (purified by affinity chromatography) has allowed to develop a semiautomatized enzyme immunoassay (EIA). A dispenser was used to add all common reagents (antibody, tracer, enzyme substrate); a washer was used to eliminate the unreacted molecules from the immuno-reactions. After addition of the enzyme substrate (Ellman's reagent), the reaction was allowed to proceed during one hour and the optical density was measured at 414 nm using an automatic reader. Using the same antiserum (kind gift of Dr. Rokach, Merck Frosst, Canada) at appropriate dilutions (1/30,000 for LTC4 AChE versus 1/6,000 for 3HLTC4) the sensitivities were compared. LTC4 was detectable in the range of 3.3 to 84 femtomoles/well corresponding to a 12–75% displacement of initial binding (i.e. approximately 2–50 pg/well) with LTC4-AChE as compared with 80–1000 pg/tube for 3H. The 50% inhibition was approximately obtained at 15 pg/tube, respectively. The determination of LTC4 on human neutrophils stimulated by various stimuli was performed without any extraction. The results obtained by this technique have been validated by comparing them to those obtained using a quantitative HPLC method. It was also possible to use the same labeling technique for prostaglandin D2-methoxamine, 6-keto PGFlα and TXB2. For all these EIA, the 50% diplacement of initial binding was 2–3 pg/well. 相似文献
114.
A M Baldassarre A Mastino V Del Gobbo 《Bollettino della Società italiana di biologia sperimentale》1984,60(1):147-151
The effects of a synthetic thymosin alpha1 on the azathioprine-sensitivity of spleen cells and on the thymic-like activity of serum from adult thymectomized mice, were observed. Thymosin alpha1 is able to restore the lowered levels of these T-dependent functions after in vivo administration. 相似文献
115.
Four healthy non obese young volunteers were observed for a 24-hr period, every other month, over the course of one year. Tolbutamide was injected i.v. each day of the experiment every four hours. Tolbutamide-induced insulin secretion (T.I.I.S.) was evaluated by planimetrically measuring insulin areas above basal levels. Tolbutamide-induced hypoglycemic effect was evaluated by measuring the blood glucose difference between the 5th and 25th minute after the drug injection (delta G5'-25'). The macroscopic evaluation of T.I.I.S. and delta G5'-25' (mean chronograms) permitted the detection of the existence of a circannual variation of both variables. In particular the maximum level of the blood glucose drop (delta G5'-25') was registered in February. Subsequently the quantification of the rhythm of T.I.I.S. was obtained by fitting a sine curve, according to the Cosinor method. The highest insulin release was confirmed in winter. As previously documented, the existence of a statistically significant circadian rhythm of T.I.I.S. was confirmed in the morning, i.e. the same period of the day in which insulin-induced hypoglycemia occurs. 相似文献
116.
Structural requirements in the reaction of morphine uridine diphosphate glucuronyltransferase with opioid substances. 下载免费PDF全文
The influence of the 3-hydroxyl and N-alkyl groups in the reactivity of narcotic compounds with morphine UDP-glucuronyltransferase was studied. Opioids possessing both, one or none of these groups were tested for inhibition of morphine glucuronidation in rabbit liver microsomal preparations. Compounds with only a 3-hydroxyl group (normorphine) or an N-methyl group (codeine, ethylmorphine) were less potent competitive inhibitors than those containing both groups (dextrorphan). Norcodeine, with neither of these groups, had no inhibitory effect. The synthetic narcotics (+)- and (-)-methadone, (-)-alpha-acetylmethadol and meperidine, with only an N-alkyl group, were effective competitive inhibitors. No stereoselectivity of the morphine glucuronyltransferase for opioid isomers was observed, and [methionine]enkephalin does not react with morphine glucuronyltransferase. Differences of pKa values and water/lipid solubility of narcotics could not explain the effects. Results indicate that the N-alkyl group plays a critical role in the interaction of narcotics with the morphine UDP-glucuronyltransferase. 相似文献
117.
Formation and utilization of 3-hydroxy-3-methylglutarate in liver mitochondria of starved and streptozotocin-diabetic rats. 下载免费PDF全文
Kidney and liver mitochondria of rat, rabbit and guinea pig are able to transform 3-hydroxy-3-methylglutarate into acetoacetate, whereas ox liver mitochondria and rat mitochondria of heart, diaphragm and brain do not exhibit such an activity. Starvation and streptozotocin treatment decreases the formation of acetoacetate from 3-hydroxy-3-methylglutarate. Addition of acetoacetate and succinate to the incubation media of mitochondria results in a decrease in the transformation of 3-hydroxy-3-methylglutarate into acetoacetate. A 3-hydroxy-3-methylglutaryl-CoA hydrolase is present in rat liver mitochondria; the activity does not show appreciable changes after starvation or streptozotocin treatment. 相似文献
118.
L. R. Guy Valadon Mohamed Osman Rosemary S. Mummery Simone Jerebzoff-Quintin S. Jerebzoff 《Physiologia plantarum》1982,56(2):199-203
An action spectrum for carotenogenesis in V. agaricinum has maxima at 395, 433, 660 and 737 nm. In a previous study it had been shown that a light-minus-dark difference spectrum of a crude extract from V. agaricinum had maxima at 390 and 420 nm, and furthermore a red, far-red interaction suggesting phytochrome involvement has been proposed. All these data suggest that there may be at least two photoreceptor systems operating in the photoinduction process here; one for the near-ultraviolet (UV-A)-mediated carotenogenesis, presumably a novel pigment, and the other for the red, far-red region, most likely phytochrome. 相似文献
119.
Capillaries of the adrenal cortex possess aminopeptidase A and angiotensin-converting-enzyme activities. 总被引:6,自引:0,他引:6 下载免费PDF全文
The enzymes required to convert the prohormone angiotensin I into angiotensins II and III, secretagogues of aldosterone, are enriched in association with capillary endothelium isolated from rat adrenal cortex. Thus the secretion of aldosterone may be controlled, in part, by processing of peptides occurring within the adrenal gland itself. 相似文献
120.
Mercedes Hernandez-Asensio Francisca F. Del Campo 《Archives of biochemistry and biophysics》1980,200(1):309-318
The rate of α-methylglucoside efflux from wild-type cells of Escherichia coli K-12 is enhanced by different substrates, as long as they are readily respired. A similar enhancement takes place in strains with impaired oxidative phosphorylation (unc mutants), regardless of their being able (strains AN120, N144, and AN382) or unable (strain NR70) to energize the membrane through respiratory electron flow. The uncouplers carbonylcyanide-m-chlorophenylhydrazone and tetrachlorosalicylanilide do not diminish the efflux acceleration in wild-type strains or unc mutants. However, the stimulation of α-methylglucoside efflux does not occur in the mutant AN59 which cannot perform a normal respiratory electron transport due to a defective synthesis of ubiquinone. The failure to stimulate the efflux is observed with succinate, which is a typical substrate of respiration, as well as with substrates which can yield ATP both at respiratory and substrate levels such as gluconate or glycerol. Moreover, potassium cyanide nullifies the acceleration of α-methylglucoside efflux caused in any type of strain and by any substrate. These results show that neither ATP nor an energized state of the membrane appears to be needed for respiration to accelerate α-methylglucoside release from E. coli cells, and question the existence of any energy-requiring reaction for αMG exit, previously proposed by other authors. 相似文献