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1.
Platelet glycerol lysis membranes and α-granule membranes were compared with respect to protein and lipid composition. Crossed immunoelectrophoresis using antibodies against whole platelets, and sodium dodecyl sulphate polyacrylamide gel electrophoresis, revealed the presence of the glycoproteins IIb and IIIa, myosin and an antigen termed G4 in both membrane fractions. The glycoproteins Ia, Ib and IIIb, in addition to β2-microglobulin and actin, appeared specific for the glycerol lysis membranes, whereas two antigens, termed G8 and G18, were observed only in the α-granule membranes. The localization of glycoprotein IIa was inconclusive. Comparison with the surface-located proteins revealed that the glycerol lysis membranes represented a reasonable approximation to a plasma membrane preparation. Radioactively labelled immunoprecipitates obtained after crossed immunoelectrophoresis of 125I-labelled platelets were cut out and applied to sodium dodecyl sulphate electrophoresis on polyacrylamide slab gels. Autoradiography of the dried gels revealed that antigen G4 represented a protein with an average molecular weight of 146 000 in its unreduced state and 132 000 in its reduced state. Antigen G18 represented a protein of molecular weight 130 000–135 000 in the reduced as well as unreduced state. Quantitation of protein and lipids showed that the α-granule membranes contained about one-third as much cholesterol and 2-times as much protein in relation to phospholipids as compared to the glycerol lysis membranes. No significant difference between the two membrane preparations was found as regards the composition of their phospholipids. 相似文献
2.
Monocytes and platelets share the glycoproteins IIb and IIIa that are absent from both cells in Glanzmann''s thrombasthenia type I. 总被引:7,自引:0,他引:7
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The possibility that thyroxine (T4) itself exerts the hormonal effect in vivo on the rat liver nuclear receptor was studied with the aid of iopanoic acid (IOP), an inhibitor of the conversion of T4 into tri-iodothyronine (T3). After administration of 2.4 micrograms of T4/100 g body weight to hypothyroid rats for 7 days, T4 and T3 concentrations in serum and in the liver nuclear non-histone protein (NHP) were all increased to the hyperthyroid range. Hepatic mitochondrial alpha-glycerophosphate dehydrogenase (alpha-GPD) activity and DNA content increased significantly. The equilibrium association constant (Ka) of the nuclear T3 receptor was unchanged and the maximal binding capacity (Cmax.) increased 1.4-fold. Simultaneous administration of IOP (5 mg/100 g body weight) to the rats given 2.4 micrograms of T4/100 g body weight completely blocked the conversion into T3. The serum T4 was even more increased, whereas the serum T3 decreased to the hypothyroid range. Although the NHP-bound T4 was at a concentration comparable with the rats given T4 alone, no NHP-bound T3 was detected. Yet the alpha-GPD activity was elevated 2.8-fold and the DNA content increased to the same extent as observed in the rats given T4 alone. The Ka and Cmax. of the nuclear receptor were significantly decreased. After administration of 48 or 480 micrograms of T4/100 g body weight for 3 days, serum T4 and T3 were markedly increased. The NHP-bound T3 was also increased, but no NHP-bound T4 was detected. The alpha-GPD activity was markedly elevated, but the DNA content was unchanged. The Cmax. per g of liver was increased, whereas the Ka remained unchanged. Simultaneous administration of IOP to these animals could not completely block the T4 conversion. The observed hormonal effects in the absence of nuclear T3 indicate that T4 possesses the intrinsic hormonal activities on the rat liver. T4 is less potent in induction of alpha-GPD activity but as potent in increment of hepatic DNA as T3. Although the binding site for T4 is not fully characterized, it appears to be acidic NHP. T4 is an active hormone, yet is also a prohormone of T3, offering the closest analogy with testosterone. 相似文献
3.
Kealoha Andrea K. Doyle Shawn M. Shamberger Kathryn E. F. Sylvan Jason B. Hetland Robert D. DiMarco Steven F. 《Coral reefs (Online)》2020,39(1):119-132
Coral Reefs - On July 25, 2016, turbid water and dead corals, sponges and other invertebrates were discovered at the East Bank (EB) of the Flower Garden Banks (FGB) National Marine Sanctuary.... 相似文献
4.
The antimicrobial effect of soluble beta-1,3-D-glucan from Sclerotinia sclerotiorum (SSG) was examined in mice experimentally infected intraperitoneally (i.p.) with Streptococcus pneumoniae serotypes 4 and 6B. SSG was administered i.p. either 3 days before challenge or 3-48 h after challenge. The number of bacteria in blood samples and the mouse survival rates were recorded. Pre-challenge SSG administration protected dose-dependently against both S. pneumoniae type 4 and 6B infections. SSG injected 24 h post-challenge had a curative effect against type 6B but not type 4 pneumococcal infection. The data demonstrate that SSG administered systemically protects against pneumococcal infection in mice. 相似文献
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6.
A mechanism for offshore initiation of harmful algal blooms in the coastal Gulf of Maine 总被引:6,自引:0,他引:6
Mcgillicuddy D. J. Jr; Signell R. P.; Stock C. A.; Keafer B. A.; Keller M. D.; Hetland R. D.; Anderson D. M. 《Journal of plankton research》2003,25(9):1131-1138
A combination of observations and model results suggest a mechanismby which coastal blooms of the toxic dinoflagellate Alexandriumfundyense can be initiated from dormant cysts located in offshoresediments. The mechanism arises from the joint effects of organismbehavior and the wind-driven response of a surface-trapped plumeof fresh water originating from riverine sources. During upwelling-favorablewinds, the plume thins vertically and extends offshore; downwellingwinds thicken the plume and confine it to the nearshore region.In the western Gulf of Maine, the offshore extent of the riverplume during upwelling conditions is sufficient to entrain upward-swimmingA. fundyense cells germinated from offshore cyst beds. Subsequentdownwelling conditions then transport those populations towardsthe coast. 相似文献
7.
William M. Reichmann Elena Losina George R. Seage III Christian Arbelaez Steven A. Safren Jeffrey N. Katz Adam Hetland Rochelle P. Walensky 《PloS one》2010,5(1)
Background
In the context of a randomized controlled trial (RCT) on HIV testing in the emergency department (ED) setting, we evaluated preferences for survey modality and data quality arising from each modality.Methods
Enrolled participants were offered the choice of answering a survey via audio computer assisted self-interview (ACASI) or pen and paper self-administered questionnaire (SAQ). We evaluated factors influencing choice of survey modality. We defined unusable data for a particular survey domain as answering fewer than 75% of the questions in the domain. We then compared ACASI and SAQ with respect to unusable data for domains that address sensitive topics.Results
Of 758 enrolled ED patients, 218 (29%) chose ACASI, 343 chose SAQ (45%) and 197 (26%) opted not to complete either. Results of the log-binomial regression indicated that older (RR = 1.08 per decade) and less educated participants (RR = 1.25) were more likely to choose SAQ over ACASI. ACASI yielded substantially less unusable data than SAQ.Conclusions
In the ED setting there may be a tradeoff between increased participation with SAQ versus better data quality with ACASI. Future studies of novel approaches to maximize the use of ACASI in the ED setting are needed. 相似文献8.
Rune Aune Mentzoni Bj?rn S?trevik Helge Molde Nora Wiium J?rn Hetland Ida Fagerland Linn Tinnesand Nordnes Sunniva Straume Storemark Ingrid Nesdal Fossum St?le Pallesen 《PloS one》2014,9(10)
The use of nicotine in the form of “snus” is substantial and increasing in some geographic areas, in particular among young people. It has previously been suggested that addictions may operate through a mechanism of attentional bias, in which stimuli representative of the dependent substance increase in salience, thus increasing the addictive behavior. However, this hypothesis has not been tested for the case of snus. The current experiment used a modified Stroop task and a dot-probe task to investigate whether 40 snus users show an attentional bias towards snus-relevant stimuli, compared to 40 non-snus users. There were no significant differences between the two groups on reaction times or accuracy on either Stroop or dot-probe task, thus failing to show an attentional bias towards snus-relevant stimuli for snus users. This could imply that other mechanisms may contribute to maintenance of snus use than for other addictions. However, this is the first experimental study investigating attentional bias in snus users, and more research is warranted. 相似文献
9.
The synthesis of thromboplastin, a potent trigger of blood coagulation, can be induced in human peripheral blood monocytes. Indirect evidence suggests that newly synthesized thromboplastin becomes in part available on the cell surface. We have attempted to study the localization and availability of thromboplastin more directly by isolating plasma membranes from isolated human peripheral blood monocytes. The specific activities of the plasma membrane markers increased 16-22-fold in these preparations with a recovery of about 15%. The contamination by mitochondria, lysosomes, nuclei and endoplasmic reticulum was low as estimated by marker enzymes and electron microscopy. In both unstimulated and stimulated monocytes thromboplastin was largely recovered in this plasma membrane fraction, providing direct evidence for its membrane localization. Phospholipase C (E.C. 3.1.4.3) is a potent inactivator of thromboplastin through its hydrolysis of the phospholipids necessary for thromboplastin activity [Otnaess, Prydz, Bjørklid & Berre (1972) Eur. J. Biochem. 27, 238-243]. About 70% of the total membrane thromboplastin activity was inactivated when whole cells were treated with phospholipase C and the membranes subsequently isolated. Following stimulation to induce thromboplastin synthesis, the plasma membranes showed a shift in their relative content of phosphatidylcholine and phosphatidylethanolamine consistent with a transmethylation process. 相似文献
10.
Tue Wenzel Kragstrup Babak Jalilian Kresten Krarup Keller Xianwei Zhang Julie Kristine Laustsen Kristian Stengaard-Pedersen Merete Lund Hetland Kim H?rslev-Petersen Peter Junker Mikkel ?stergaard Ellen-Margrethe Hauge Malene Hvid Thomas Vorup-Jensen Bent Deleuran 《PloS one》2016,11(2)