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281.
R H Ward B Modell M Petrou F Karag?zlu E Douratsos 《BMJ (Clinical research ed.)》1983,286(6377):1542-1544
Samples of chorionic villi were obtained in the first trimester by aspiration using a cannula passed transcervically under the guidance of real time ultrasound. In initial studies in 47 anaesthetised patients immediately before therapeutic abortion a method was developed giving a success rate of 89%. In 10 patients successful sampling was performed as an outpatient procedure without anaesthesia. In all, seven diagnostic procedures were undertaken and four of the five unaffected pregnancies continued. The technique of chorionic villous sampling using real time ultrasound is simple to learn and yields material for biochemical analysis and chromosomal study without the need for tissue culture. The exact obstetric risk, however, remains to be defined. 相似文献
282.
Within the past year, it has become apparent, in connection with its use on automatic flow cytometers, that the quality of commercially available Alcian Blue has significantly declined. A homologous series of alkylated (C1-C7) Astra Blue quaternary ammonium halides was prepared, characterized, and evaluated for the detection of basophils in whole blood. On the Technicon H6000 flow cytometer, the resolution of the basophil cluster from the main population of unstained white blood cells was found to depend on the chain length of the quaternizing alkyl group. Optimal basophil resolution was observed for the n-propyl derivative. Correlation of the new method vs Alcian Blue as the reference on the H6000 was expressed as follows: %Baso (Astra Blue) = 0.89% Baso (Alcian Blue) + 0.12% for 180 fresh whole blood samples. Within-run precision at a basophil differential count of 0.73% was characterized by SD = 0.11, identical to that obtained for Alcian Blue. Aqueous solutions of n-propyl Astra Blue iodide, in contrast to Alcian Blue, are thermally stable. Heating the reagent for 1 h at 100 degrees C did not alter solubility or cytochemical behavior. In contrast, parallel treatment of Alcian Blue yielded insoluble material by hydrolysis of the isothiouronium groups. The reagent for basophil detection comprises n-propyl Astra Blue iodide, lanthanum chloride, sodium chloride, Tween 20, and cetylpyridinium chloride. The Astra Blue derivatives were characterized by uv-vis, ir, percentage halide, paper chromatography, and 13C NMR. 相似文献
283.
284.
Summary The horseradish-peroxidase (HRP) technique was used to visualize the cell bodies of axons projecting to the goldfish pituitary. Following intravenous injections of HRP, HRP reaction products were observed in axons of the rostral pars distalis, proximal pars distalis, neurointermediate lobe, pituitary stalk and in axons coursing from the pituitary into the hypothalamus. HRP-labelled cells in the brain were localized in two regions only — the nucleus preopticus (NPO) pars magnocellularis and pars parvocellularis, and the nucleus lateralis tuberis (NLT) of the hypothalamus. These observations suggest that the NPO and NLT are the source of the neurosecretory innervation of the goldfish pituitary. 相似文献
285.
Introduction of valinomycin into erythrocyte incubation medium increased the cell stability to water-induced hemolysis. In these conditions the erythrocytes of spontaneously hypertensive and normotensive (control) rats release 63.2 +/- 1.5% and 80.9 +/- 1.6%, respectively, of the total hemoglobin content. Valinomycin effect is completely abolished with K+ substitution for Na+ and is independent of extracellular Ca2+ concentration. Valinomycin had no effect on human erythrocyte osmotic stability. It has been shown that valinomycin-induced kinetics of Na+ and K+ redistribution was different in human and rat erythrocytes. The distinctions are thought to be related to specific anion transport mediated by the third band protein--the main component of membrane cytoskeleton. 相似文献
286.
The primate cochlear nuclear complex exhibits several characteristic morphological differences in the various primate families from Lorisidae through Hominidae. The most striking differences occur in the organization of the dorsal cochlear nucleus in which the laminar pattern becomes progressively obscured. Granule cells form an external granular layer as well as being intermixed within the molecular and pyramidal layers in slow lorises and squirrel and rhesus monkeys. Whereas a prominent external granular layer remains in chimpanzees, granule cells are scant in other portions of the nucleus. Human adults lack an external granular layer. A small number of granule cells occur but with inconstant distribution. Primates lack the linear array of pyramidal cells oriented perpendicularly to the epithelial surface as seen in cats. The granule cell layer exhibits similar regression in development of the human cochlear complex. The external granular layer is prominent in the fetus but rapidly decreases in size after birth. It achieves its adult form prior to 18 months. The data suggest that neuronal attrition, or programmed cell death, may be the major mechanism accounting for the alterations that occur in the human granule cell layer. Other differences in cytoarchitecture, within the great apes and humans, include decreases in the small and giant cell populations of the cochlear complex. These changes, in consort with the organizational changes and reduction of granule cells as noted above, suggest a trend towards reduced intranuclear integration at the level of the cochlear nucleus coupled with encephalization of the auditory system. 相似文献
287.
Avian hepatic T3 generation by 5'-monodeiodination: characterization of two enzymatic pathways and the effects of goitrogens 总被引:1,自引:0,他引:1
F M McNabb L J Lyons T E Hughes 《Comparative biochemistry and physiology. A, Comparative physiology》1986,85(2):249-255
The enzymatic nature of 5'-monodeiodination (5'-D) in avian liver homogenates was demonstrated by abolishment of activity by iopanoic acid (IOP). T3 production from T4 was dependent on enzyme and substrate concentrations, incubation time, incubation temperature, and pH. Two pathways of 5'-D activity were present in avian liver and exhibited characteristics similar to those described in mammalian tissues. Type II activity was identified as propylthiouracil (PTU)-insensitive activity. Type I (PTU-sensitive) was determined by difference between Total and Type II. Km values were 1.58 microM T4 for Total activity and 0.90 nM T4 for Type II, corresponding to the characteristics of the mammalian pathways. The effects of goitrogens on avian hepatic 5'-D were equivalent to those reported for the mammalian enzyme. 相似文献
288.
289.
Fairman R. P.; Sessler C. N.; Bierman M.; Glauser F. L. 《Journal of applied physiology》1987,62(4):1363-1367
The polycation protamine sulfate increases microvascular permeability in the kidney by reducing glomerular charge. We have exposed the pulmonary vasculature to protamine sulfate to determine whether electrical charges play a role in protein permeability in lung vascular beds. In anephric rats, protamine sulfate increased hematocrit approximately 25%. With protamine sulfate doses of 0.08 and 0.04 mg/g body wt, lung blood-free wet-to-dry weight ratios were increased (5.24 +/- 0.8 and 4.89 +/- 0.7) compared with control (3.85 +/- 0.3) (P less than 0.05). In isolated, ventilated, and perfused lungs 0.04 mg/g body wt protamine sulfate increased pulmonary arterial pressure from 5.2 +/- 1.4 to 16.3 +/- 3.9 mmHg (P less than 0.01). These lungs gained weight and lung wet-to-dry weight ratios were significantly increased (15.33 +/- 4.26 compared with 6.04 +/- 0.24 for control lungs). Poly-L-lysine, another polycation, also caused significant increases in pulmonary arterial pressure, lung weight, and lung wet-to-dry weight ratios. The addition of diphenhydramine to the perfusate 10 min before the addition of protamine sulfate did not prevent these changes. Heparin (90 U/mg protamine sulfate) reversed the abnormalities. Pulmonary arterial pressure (7.0 +/- 1.1 mmHg) was not significantly different from the control value, lung weight did not increase, and the lung wet-to-dry weight ratio was 6.24 +/- 0.23 (P greater than 0.05). We conclude that polycations have a significant effect on pulmonary vascular resistance and perhaps on permeability. 相似文献
290.
S Ronchi M Galliano L Minchiotti B Curti N G Rudie D J Porter H J Bright 《The Journal of biological chemistry》1980,255(13):6044-6046
The flavoenzyme D-amino acid oxidase (Eo) is rapidly chlorinated by N-chloro-D-leucine (Rudie, N.G., Porter, D.J.T., and Bright, H.J. (1980) J. Biol. Chem. 255, 498-508). We have carried out chymotryptic digestion of E0-36Cl2 and find that all of the radiolabel is located in a heptapeptide having [3.5-36Cl2]chlorotyrosine as the COOH-terminal residue. This heptapeptide, having the sequence -Asp-Leu-Glu-Arg-Gly-Ile-Tyr-, is located within a larger fragment obtained previously from cyanogen bromide cleavage of E0. These results demonstrate that the target for chlorination in E0 must be a single tyrosine residue and provide, when taken together with previous findings, the first clear evidence for the identity and location of an active site residue in the polypeptide chain of D-amino oxidase. 相似文献